Title of Invention	METHOD FOR FIXING AN ELECTRONIC COMPONENT ON A PRINTED CIRCUIT BOARD AND SYSTEM COMPRISING A PRINTED CIRCUIT BOARD AND AT LEAST ONE ELECTRONIC COMPONENT
Abstract	In a method for fixing an electronic component (3) on a printed circuit board (2), and contact-connecting the electronic component (3) to the printed circuit board (2), the following steps are provided: - providing the printed circuit board (2) having a plurality of contact and connection pads (8), - providing the electronic component (3) having a number of contact and connection locations (5) corresponding to the plurality of contact and connection pads (8) of the printed circuit board (2), with a mutual spacing reduced in comparison with the spacing of the contact and connection pads (8) of the printed circuit board (2), and - arranging or forming at least one interlayer (4) for routing the contact and connection locations (5) of the electronic component (3) between the contact and connection pads (8) of the printed circuit board (2) and the contact and connection locations (5) of the electronic component (3). A method for producing an interlayer (4) for routing and a system having a printed circuit board (2) and an electronic component (3) using the interlayer (4) for routing are also provided.

Title of Invention

METHOD FOR FIXING AN ELECTRONIC COMPONENT ON A PRINTED CIRCUIT BOARD AND SYSTEM COMPRISING A PRINTED CIRCUIT BOARD AND AT LEAST ONE ELECTRONIC COMPONENT

Abstract

In a method for fixing an electronic component (3) on a printed circuit board (2), and contact-connecting the electronic component (3) to the printed circuit board (2), the following steps are provided: - providing the printed circuit board (2) having a plurality of contact and connection pads (8), - providing the electronic component (3) having a number of contact and connection locations (5) corresponding to the plurality of contact and connection pads (8) of the printed circuit board (2), with a mutual spacing reduced in comparison with the spacing of the contact and connection pads (8) of the printed circuit board (2), and - arranging or forming at least one interlayer (4) for routing the contact and connection locations (5) of the electronic component (3) between the contact and connection pads (8) of the printed circuit board (2) and the contact and connection locations (5) of the electronic component (3). A method for producing an interlayer (4) for routing and a system having a printed circuit board (2) and an electronic component (3) using the interlayer (4) for routing are also provided.

Full Text	METHOD FOR FIXING AN ELECTRONIC COMPONENT ON A PRINTED CIRCUIT BOARD AND SYSTEM COMPRISING A PRINTED CIRCUIT BOARD AND AT LEAST ONE ELECTRONIC COMPONENT The present invention relates to a process for attaching or fixing an electronic component on a circuit board and/or contacting the electronic component with the circuit board, as well as a process for producing an intermediate layer for disentangling contact or connection sites of an electronic component from contact or connection surfaces of a circuit board. The present invention further relates to a system including a circuit board and at least one electronic component. Electronic components to be applied on circuit boards have become increasingly complex, which has, above all, resulted in an increase of the required number of connections to the circuit board, which has in turn led to a reduction of the distances between individual or neighboring connections such as, for instance, conductive pins with an unchanged size of the electronic component. In this connection, printed circuit board manufacturers started to perform disentanglements of such components, or individual components, via conductive passages or microvias through several circuit board layers in so-called high-density interconnects or HDI boards or printed boards. With a further increase in the complexity of electronic components and the thus involved increase in the number of connections to a circuit board, and/or a further reduction of the dimensions of such electronic components, which will likewise lead to reduced distances between neighboring connections, a large increase in the number of circuit board layers is expected for the necessary disentanglement. Moreover, an increase in the complexity of such an electronic component together with reduced mutual distances linked with enhanced connections will minimize the options for realizing or arranging conductive tracks or conductive structures between individual connections, or render an arrangement impossible at all, which will immediately call for a further increase in the number of necessary circuit board layers. Additional layers of such a circuit board will, however, result in an increased thickness of the circuit board and, moreover, in increased production costs. A way of reducing the number of circuit boards is by using very fine or ultra-fine conductive structures, wherein, however, for the time being, even with the possible availability of processes for producing such fine or ultra- fine conductive structures, it is to be anticipated that the production of multilayer circuit boards including such ultra-fine conductive structures in usual production formats of high-density interconnects, such as, e.g., 18 x 24 inch, does not enable the orientation of circuit board layers with sufficient precision in order to, for instance, provide conductive connections between individual board layers where such ultra-fine conductive tracks or conductive structures are provided. From WO 01/43190 Al there has become known a liquid crystal display, wherein a substrate having connecting or contact surfaces is coupled or connected with an electronic component by using an intermediate device. From US 2005/0133891 Al there has become known a system consisting of a circuit board or printed circuit board and an electronic component, wherein the electronic component is coupled with the circuit board or the substrate via intermediate connecting locations. Moreover, from US 6,429,534 Bl there can be taken a frame-like element for coupling a circuit board and an electronic component to be fixed on the circuit board, wherein the frame-like element surrounds the electronic component being fixed on the circuit board and a coupling is provided between the connecting locations or sites of the electronic component facing away from the circuit board and respective connecting or contact surfaces of the circuit board by wire connections, which are provided between the connecting or contact surfaces of the electronic component and respective wiring paths or tracks on the frame-like element on the one side and between the wiring paths on the frame-like element and the respective contact surfaces of the circuit board on the other hand, so that much effort is necessary for coupling the connecting areas of the electronic component with respective or dedicated connecting areas of the circuit board by arranging a very large number of wire connections. Based on a process of the initially defined kind as well as a system of the initially defined kind, the present invention, therefore, aims to avoid the above-mentioned problems with regard to the use of electronic components of increased complexity and/or reduced size, and hence the reduction of the small mutual distances between connections to the circuit board, by a substantially unchanged circuit board design and, in particular, to enable the disentanglement of such highly complex components of, in particular, small dimensions while avoiding additionally required circuit board layers. To achieve the above-mentioned objects, a process for attaching or fixing an electronic component on a circuit board and/or contacting the electronic component with the circuit board is essentially characterized by the steps of: - providing the circuit board with a plurality of contact or connection surfaces; - providing the electronic component with a number of contact or connection sites corresponding to the plurality of contact or connection surfaces of the circuit board, at mutual distances reduced relative to the distances of the contact or connection surfaces of the circuit board; and - arranging or forming between the contact or connection surfaces of the circuit board and the contact or connection sites of the electronic component at least one intermediate layer for disentangling the contact or connection sites of the electronic component. Due to the fact that according to the invention, after having provided the circuit board or printed circuit board with a plurality of contact or connection surfaces and the electronic component with a corresponding number of contact or connection sites, an or at least one intermediate layer for disentangling the contact or connection sites of the electronic component is arranged or formed between the contact or connection surfaces of the circuit board and the associated contact or connection sites of the electronic component, it has become feasible to couple with, or attach to, the circuit board, or contact the latter with, an electronic component comprising an optionally higher complexity and, consequently, a larger number of connections to the circuit board at simultaneously reduced distances between the individual connections, and/or an electronic component having reduced dimensions, without increasing the number of circuit board layers for the disentanglement between the connection sites of the electronic component and the connection sites or surfaces of the circuit board. The intermediate layer provided according to the invention may have a thickness reduced relative to the thickness of a circuit board layer, particularly of the dielectric layer or film, such that a negligible increase in the thickness of the entire circuit board will do, particularly in consideration of the fact that a circuit board of this type would usually comprise a plurality of, for instance, more than 4 and, in particular, more than 6 circuit board layers, while, at the same time, enabling the safe disentanglement in a preferably single layer or ply of the intermediate layer. If highly complex components including extremely large numbers of contact or connection sites are employed, more than one intermediate layer including the respective feedthroughs may be provided, wherein, however, even with the provision of more than one intermediate layer, unalteredly great advantages relative to the provision of an elevated number of additional board layers will be attainable, bearing in mind the strongly reduced thickness as compared to conventional circuit boards and the simplified structuring of the circuit board. It is, thus, feasible to resort to presently available techniques for forming circuit boards having a plurality of circuit board layers, in particular when taking into account the precision requirements for the alignment of individual subregions of such circuit board layers, while the appropriate, very fine or ultra-fine conductive tracks or structures may be provided in the region of the intermediate layer for disentanglement, while accordingly- large partial regions or contact zones may be provided on the intermediate layer for the respective contacting or connection of the contact or connection sites of the electronic component as well as the connection or contact surfaces of the circuit boards. As already indicated above, it will do for disentanglement to use an intermediate layer having a simplified structure as compared to usual circuit board layers, it being preferably proposed in this respect that the intermediate layer is formed with conductive tracks or structures between contact zones corresponding to the contact or connection sites of the electronic component and corresponding to the contact or connection surfaces of the circuit board. Since the intermediate layer is merely formed with conductive tracks or structures between contact zones corresponding to the contact or connection sites of the electronic component and corresponding to the contact or connection surfaces of the circuit board, the arrangement or formation of very fine or ultra-fine conductive tracks or structures may be provided, which can, for instance, be formed by known techniques on or in the intermediate layer such that the mutual distances of the connections of such components, which are reduced when using complex components, do not constitute any restriction in view of the possibility of realizing or providing conductive tracks in the intermediate layer. In order to ensure reliable contacting between the electronic component and the intermediate layer for disentanglement, it is proposed according to a preferred embodiment that contacting between the contact or connection sites of the electronic component and the intermediate layer is realized via contacts of the electronic component. According to a modified embodiment, it is preferably- proposed by the invention that contact or connection sites of the electronic component are directly contacted with contact zones of the intermediate layer, thus enabling a further reduction of costs for the attachment of the electronic component to the circuit board, and also an improved connection or fixation of electronic components on a circuit board while interposing the intermediate layer for disentanglement, by a reduction of connections, for instance welds or bonds. According to a further preferred embodiment, it is proposed that the intermediate layer is merely formed in the region of the contact or connection surfaces of the circuit board as well as the contact or connection sites of the electronic component, so that accordingly reduced material expenditures will be involved in the formation of the intermediate layer, since the latter merely need be provided in the region of the attachment of the or an electronic component on the circuit board while, at the same time, taking into account the increased distances between the individual contact or connection surfaces of the circuit board relative to the distances of the contact or connection sites of the electronic component. For a further cost reduction and/or formation of a compact overall structure, in particular when assembling the electronic component and the circuit board, it is proposed according to a further preferred embodiment that the electronic component is attached on the circuit board with contact or connection surfaces oriented away from the circuit board, and is overlaid by the intermediate layer for disentanglement and connection to the contact or connection surfaces of the circuit board. Thus, in addition to offering the chance of disentanglement via the intermediate layer having an extremely small thickness, also a supporting function for the electronic component will be fulfilled such that an additional carrier substrate for the electronic component will be obviated so as to not only enable a reduction of the size of the overall system comprised of the circuit board and the at least one electronic component, but also a reduction of the overall costs. To achieve the objects mentioned in the beginning, a process for producing an intermediate layer for disentangling contact or connection sites of an electronic component from contact or connection surfaces of a circuit board is, moreover, essentially characterized by the steps of: - providing the circuit board with a plurality of contact or connection surfaces; - forming a base material of the intermediate layer at least in the region of the contact or connection surfaces of the circuit board; structuring the intermediate layer to form conductive tracks or structures and contact sites for contacting with contact or connection surfaces of the circuit board and with contact or connection sites of an electronic component to be attached on the circuit board. As already pointed out above, it is feasible in a simple manner, after having provided the circuit board with a plurality of contact or connection sites, to make the at least one intermediate layer for disentanglement available for an electronic component to be subsequently attached. For a reliable formation of the intermediate layer comprising, in particular, very fine or ultra-fine conductive tracks or structures, it is, moreover, proposed that the structuring of the intermediate layer is performed by subtractive techniques, semi-additive techniques, additive techniques and/or embossing techniques or laser structuring techniques known per se, as in correspondence with a preferred embodiment of the process for producing the intermediate layer for disentanglement according to the invention. For receiving, or fulfilling the function of a support for, an electronic component to be subsequently attached to the circuit board upon interposition of the intermediate layer for disentanglement, it is proposed according to a further preferred embodiment that, after the structuring of the intermediate layer, an additional support layer for the attachment or contacting of the electronic component is applied on the intermediate layer for disentanglement and provided with contacts for the electronic component. As already mentioned above, it may preferably be provided according to the invention, particularly in consideration of the fact that the intermediate layer for disentanglement merely contains very fine or ultra-fine conductive tracks or structures in addition to the contact zones to be provided for contacting with the electronic component as well as the circuit board, that the intermediate layer is formed with a thickness reduced- relative to the thickness of a circuit board layer. In this connection, it is proposed according to a particularly preferred embodiment that the thickness of the intermediate layer is selected to be less than half, in particular less than a third, of the thickness of a circuit board layer. It is, thus, feasible to do, for instance, with intermediate layers having dielectric film thicknesses of below, e.g. 35 to 40 μm, in particular down to 10 μm or less, while a typical dielectric film thickness of an HDI circuit board amounts to at least 60 μm, e.g. more than 80 μm. For the disentanglement of the junction, or contact or connection sites of the electronic component, very fine or ultra-fine conductive structures will do in the intermediate layer, wherein it is proposed in this respect according to a further preferred embodiment that the intermediate layer is provided with conductive tracks or conductive structures whose widths are selected to be less than 50 μm, in particular less than 30 μm. As already indicated above, it is feasible according to a further preferred embodiment, in particular with a view to further reducing costs and simplifying the formation and attachment of the electronic component, that the intermediate layer is used as a support and/or enclosure for the electronic component. To achieve the initially mentioned objects, a system including a circuit board and at least one electronic component, moreover, is essentially characterized in that at least one intermediate layer for the disentanglement of contact or connection sites of the electronic component from contact or connection surfaces of the circuit board is arranged or formed between the contact or connection sites of the electronic component and the contact or connection surfaces of the circuit board, and that the contact or connection sites of the electronic component comprise mutual distances reduced relative to the contact or connection sites of the circuit board. It is, thus, feasible to ensure disentanglement merely by providing at least one intermediate layer having a comparatively small thickness, said intermediate layer being preferably provided or providable merely partially in the region of the contact or connection surfaces of the circuit board and of the contact or connection sites of the electronic component to be connected therewith, as already indicated above. According to a preferred embodiment, it is proposed in this respect that the intermediate layer is formed with conductive tracks or structures between contact zones corresponding to the contact or connection sites of the electronic component and corresponding to the contact or connection surfaces of the circuit board. To simplify the attachment and contacting of the electronic component, it is, moreover, proposed that an additional support layer for the attachment and contacting of the electronic component is applied on the intermediate layer for disentanglement and provided with contacts for the electronic component, as in correspondence with a further preferred embodiment of the system according to the invention. As already indicated several times, it may preferably be provided that the intermediate layer is formed with a thickness reduced relative to the thickness of a circuit board layer, wherein it is proposed according a particularly preferred embodiment that the thickness of the intermediate layer is less than half, in particular less than a third, of the thickness of a circuit board layer. In addition, it is preferably proposed that the intermediate layer is provided with conductive tracks or conductive structures whose widths are less than 50 μm, in particular less than 30 μm. For the use of unpackaged electronic components and in order to facilitate the attachment to a circuit board and contacting with the same, it is proposed according to a further preferred embodiment that the intermediate layer is used as a support and/or enclosure for the electronic component. As already indicated several times, the intermediate layer for disentanglement according to the invention is preferably usable, in particular, in connection with a circuit board having a plurality of circuit board layers, wherein it is, moreover, proposed that the circuit board in a manner known per se is formed with a plurality of superimposed circuit board layers which are at least partially interconnected by conductive passages or microvias connecting individual circuit board layers, as in correspondence with a further preferred embodiment of the system according to the invention. In the following, the invention will be explained in more detail by way of exemplary embodiments schematically illustrated in the accompanying drawing. Therein: Fig. 1 is a partial section through a system according to the invention, which is comprised of a circuit board and an electronic component attached thereto, using an intermediate layer according to the invention for disentanglement; Fig. 2 schematically illustrates individual steps for carrying out the process according to the invention for attaching an electronic component to a circuit board while forming or arranging an intermediate layer for disentanglement; Fig. 3 schematically illustrates individual process steps for forming an intermediate layer for disentanglement to be used in the process according to the invention and in the system according to the invention, respectively; Fig. 4, in an illustration similar to that of Fig. 1, depicts in detail an electronic component of a system according to the invention, on a scale reduced relative to that of Fig. 1; Fig. 5, in an illustration similar to that of Fig. 4, depicts a further modified embodiment of a system according to the invention, with an unpackaged electronic component being integrated; Fig. 6, in an illustration similar to those of Figs. 4 and 5, depicts a further modified embodiment of a system according to the invention, with the electronic component being directly applied on the intermediate layer for disentanglement; and Fig. 7, in an illustration again similar to those of Figs. 4 to 6, depicts a further modified embodiment of the system according to the invention, with the intermediate layer for disentanglement being applied on a component integrated in the circuit board. Fig. 1 schematically illustrates a system 1 which is comprised of a printed circuit board, in particular an HDI board 2 having a plurality of board layers, and an electronic component 3 to be contacted with, and attached to, the former with an intermediate layer 4 for disentanglement arranged between the electronic component 3 and the circuit board 2. As is apparent from Fig. 1, the intermediate layer 4 comprises a plurality of contact or connection zones 6 corresponding to the number of contact or connection sites 5 of the electronic component 3, which contact or connection zones 6 are either substantially directly coupled with contact or connection zones 7 corresponding to contact or connection surfaces 8 provided on the circuit board 2. From Fig. 1, it is apparent that the distances between neighboring contact or connection sites 5 of the electronic component 3 are smaller than the distances between neighboring contact or connection surfaces 8 of the circuit board 2 such that, for a disentanglement in the intermediate layer 4, very fine or ultra-fine conductive tracks or conductive structures are additionally included to provide connections with further contact or connection zones 7 of the intermediate layer 4, via which contacting with connection or contact surfaces 8 of the circuit board 2 is subsequently effected. As opposed to the known prior art, where immediate contacting between the connection or contact sites or connections 5 of the electronic component 3 with the associated connection or contact surfaces 8 of the circuit board 2 is realized, optionally by providing conductive passages or microvias for the disentanglement of the connection or contact sites 5 of the highly complex electronic component 3, the configuration according to Fig. 1 ensures complete disentanglement via the intermediate layer 4. In the configuration according to Fig. 1, the intermediate layer 4 for disentanglement is merely provided in the region of the contact or connection sites 5 of the electronic component 3 as well as the connection or contact surfaces 7 of the circuit board 2 such that a partial formation of the intermediate layer 4 will do. Moreover, the thickness of the intermediate layer is not represented to scale relative to the size or dimensions of both the circuit board 2 and the electronic component 3 in any of the Figures. Taking into account the very fine or ultra-fine conductive tracks or conductive structures 9, which may, for instance, have widths of less than 50 μm, e.g. about 25 μm, a thickness of the dielectric film for the intermediate layer 4 in the order of about 35 μm will do, this being less than half of the usual thickness of the dielectric film of a board layer of a circuit board 2. Moreover, thicknesses for the dielectric film of the intermediate layer 4 of up to 10 μm or therebelow are usable or applicable. The circuit board 2 illustrated in the Figures is, moreover, for instance, comprised of a plurality of circuit board layers, which are, however, not illustrated or indicated separately. In the embodiment represented in Fig. 1, contacting between the intermediate layer 4 for disentanglement and the connection or contact sites 5 of the component 3 is realized via conductive contacts 10, which are received or provided in a carrier layer or support structure schematically indicated by 11. Instead of the merely partial arrangement of the intermediate layer 4 for disentanglement in correspondence with the contact or connection surfaces 8 of the circuit board 2 as well as the contact or connection sites 5 of the electronic component 3, the intermediate layer 4 and, in particular, the base material of the same may be applied or provided substantially all-over the surface of the circuit board 2, the respective structuring with the contact zones 6 and 7, respectively, as well as the conductive tracks 9 being merely provided or formed in the region of the attachment or contacting of the or an electronic component 3 on the circuit board 2. Fig. 2 schematically depicts a process sequence for producing a system 1 comprised of a circuit board and an electronic component, while using or forming an intermediate layer 4 for disentanglement. In step (a), a circuit board, in particular a HDI board 2, is provided, wherein appropriate connection or contact surfaces 8 are already formed and indicated. In step (b), a base material for the intermediate layer 4 is applied, whereupon in step (c) the structuring of the contact or connection zones 6 and 7, respectively, as well as the conductive tracks 9 of the intermediate layer 4 is performed, an exemplary process for structuring the intermediate layer 4 being discussed below with reference to Fig. 3. Following the structuring or formation of the intermediate layer 4 for disentanglement, the application of additional plies or support layers 11 and 12 is effected in step (d), whereupon, according to step (e), the structuring and finishing of the support layers or plies 11 and 12 is carried out, for instance by providing contacts 10. Finally, in step (f), the electronic component 3 is coupled or connected to the intermediate layer 4 for disentanglement, and subsequently with the circuit board 2, via the connection or contact sites 5, while interposing contacts 10. Fig. 3 schematically illustrates the partial steps of a process for structuring or forming an intermediate layer 4, using, for instance, an embossing technique known per se. It should further be noted that, for the formation or structuring of the intermediate layer 4 for disentanglement, structuring is merely performed on just one side as opposed to the double-sided structuring of an extremely fine conductor structure generally indicated in Fig. 3. In step (a) according to Fig. 3, embossing of the intermediate layer 4 is carried out using, for instance, an embossing tool 13 to emboss a relief structure on a thermo- plastic foil. In step (b), possibly remaining residual materials are, for instance, removed by reactive ion etching in order to enable the production of throughgoing holes or microvias 14, whereupon, according to step (c), the application of a seed layer of a thin, conductive material is realized over the entire surface. Such an application may, for instance, be effected by sputtering or thermal vapor deposition. After this, the relief structure is coppered according to step (d), and the projecting copper built up by the galvanization process is removed in step (e), for instance by chemical or mechanical processes, so as to enable, as a function of the desired structure of the intermediate layer 4, the formation of contact zones 6 and 7 according to the positions of the contact or connection sites 5 of the electronic component 3 and the contact or connection surfaces 8 of the circuit board 2 as well as the required ultra-fine conductive tracks 9. For the production of the intermediate layer 4, thermoplastic materials like, e.g., polyetherimide, liquid crystal polymer (LCP) may be used. Alternatively to the use of thermoplastic materials, thermally or UV-curable materials may be employed for the structuring of the intermediate layer 4. Furthermore, the application of a conductive layer described in steps (c) and (d) may be replaced with the filling of the depressions or recesses with a conductive material. Instead of using an embossing technique, the removal of the polymer material used for the intermediate layer 4 may, for instance, be done by the aid of laser light. For the structuring of the circuit board or the arrangement of the conductive connection or contact zones 6 and 7, respectively, as well as the conductive tracks 9, known subtractive techniques, semi-additive techniques or additive techniques may, moreover, be employed. In the exemplary embodiments illustrated in Figs. 4 to 7, the reference numerals of the preceding Figures, in particular those of Fig. 1, have been retained for identical components. According to the illustration of Fig. 4, the attachment of the electronic component 3 is again realized via contacts 10 on the intermediate layer 4 for contacting with the circuit board 2, wherein Fig. 4, in addition, depicts the electronic component 3 in greater detail, from which it is, in particular, apparent that the latter is arranged on a plate-shaped support structure 15 and surrounded by a sheathing 16. From the modified illustration according to Fig. 5, it is apparent that an electronic component again denoted by 3 is inserted without the support structure and sheathing structure 15 and 16, respectively, illustrated in Fig. 4, but is directly connected or coupled, via connection or contact sites again denoted by 5, with the respective contact zones 6 of the intermediate layer 4 for disentanglement, via which a connection or junction to the circuit board again denoted by 2 is subsequently realized via the connection or contact surfaces 8. In the configuration according to Fig. 5, the intermediate layer 4 for disentanglement, moreover, serves directly as a support structure and, hence, fulfils a supporting or carrying function for the electronic component 3 such that additional contacts may be obviated. This results in a reduction of costs and, at the same time, an enhanced connection of the electronic component 3 to the intermediate layer 4 and, hence, to the circuit board 2. For the proper fixation and protection of the unpackaged component 3, a sheathing 17 surrounding the electronic component 3 and supported on the intermediate layer 4 for disentanglement is indicated in the embodiment according to Fig. 5. In the embodiment according to Fig. 6, an unpackaged electronic component 3 is employed, which is directly coupled with the intermediate layer 4 for disentanglement. Further layers 18 and 19 are indicated above the component 3, wherein, in particular in the region of these layers, additional contacts or connections 20 are indicated, which serve for the attachment of further components not shown in Fig. 6. The contacting of such further components via the connections or contacts 20 in the embodiment illustrated in Fig. 6 is again realized upon interposition of the intermediate layer 4 for disentanglement. In the embodiment represented in Fig. 7, the electronic component 3 is arranged with the connection or contact sites facing away from the circuit board 2, the intermediate layer 4 for disentanglement being arranged above the electronic component 3 and subsequent contacting being again effected with connection or contact surfaces 8 of the circuit board 2. In the embodiments according to Figs. 6 and 7, an integration of the electronic component 3 is, thus, immediately enabled, this resulting in a further integration of embedded components and an increased compactness at the simultaneous reduction of the overall size of the system. By using the intermediate layer 4 for disentanglement between the connection or contact sites 5 of the electronic component 3 and also the contact or connection surfaces 8 of the circuit board 2, an intermediate layer 4 having a reduced thickness, in particular in respect to the dielectric layer, particularly as compared to the thickness of usual circuit board layers, will thus, be enough such that, in the main, only a negligible increase in the thickness of the overall circuit board will occur. Furthermox-e, a single intermediate layer 4 for disentanglement will do in most cases, said intermediate layer 4, as opposed to usual circuit board layers, for disentanglement only comprising contact zones 6 and 7 as well as very fine or ultra-fine conductive tracks or conductive structures 9 which are adaptable to the small distances of connections or connection sites 5 of highly complex electronic components 3, without requiring a plurality of layers and, in particular, additional circuit board layers for the disentanglement of such highly complex components 3. When using electronic components 3 comprising extremely large numbers of connection or contact sites, whose number may range from some hundreds to some thousands, it may, moreover, be provided that a further intermediate layer is applied or deposited on an intermediate layer 4, for instance according to the process schematically illustrated in Fig. 3, wherein appropriate feedthroughs or microvias are provided for contacting with the circuit board 2 arranged therebelow, or the circuit board layers forming the circuit board 2. Bearing in mind the fact that the thickness of such an optionally required, additional intermediate layer 4 is again strongly reduced as compared to the thickness of an additional circuit board layer and, in particular, its dielectric layer, and further bearing in mind that, due to the simplified structuring of such an intermediate layer 4 for disentanglement, the latter substantially comprises but very fine or ultra-fine conductive track structures 9, a negligible increase in the overall thickness of the circuit board 2 along with the intermediate layers 4 will do even if more than one intermediate layer 4 is provided for disentanglement in the region of highly complex components 3. By contrast, it will have to be taken into account that, with an optionally sought disentanglement via additional circuit board layers, the number of circuit board layers will have to be considerably increased on account of the more complex structures of the latter as compared to the simple structure, of the intermediate layer 4 such that an accordingly high increase in the overall thickness of the circuit board 2 as well as the production costs will be involved. In addition, the arrangement of the thin intermediate layer 4 renders feasible the provision of larger connection sites or zones so as to meet the requirements of a registering accuracy of the individual layers even when using large- sized production formats of printed circuit boards and, in particular, HDI boards. The tapering or conically shaped bores provided in the region of passages will require little space considering the thickness reduction, thus lowering the requirements of a registration or orientation accuracy. Claims 1. A process for attaching an electronic component (3) on a circuit board (2) and/or contacting the electronic component (3) with the circuit board (2), characterized by the steps of: - providing the circuit board (2) with a plurality of contact or connection surfaces (8); - providing the electronic component (3) with a number of contact or connection sites (5) corresponding to the plurality of contact or connection surfaces (8) of the circuit board, at mutual distances reduced relative to the distances of the contact or connection surfaces (8) of the circuit board (2); and - arranging or forming between the contact or connection surfaces (8) of the circuit board (2) and the contact or connection sites (5) of the electronic component (3) at least one intermediate layer (4) for disentangling the contact or connection sites (5) of the electronic component (3) . 2. A process according to claim 1, characterized in that the intermediate layer (4) is formed with conductive tracks or structures (9) between contact zones corresponding to the contact or connection sites (5) of the electronic component (3) and corresponding to the contact or connection surfaces (8) of the circuit board (2). 3. A process according to claim 1 or 2, characterized in that contacting between the contact or connection sites (5) of the electronic component (3) and the intermediate layer (4) is effected via contacts of the electronic component (3). 4. A process according to claim 1 or 2, characterized in that contact or connection sites (5) of the electronic component (3) are directly contacted with contact zones of the intermediate layer (4). 5. A process according to any one of claims 1 to 4, characterized in that the intermediate layer (4) is merely formed in the region of the contact or connection surfaces (8) of the circuit board (2) as well as the contact or connection sites (5) of the electronic component (3). 6. A process according to any one of claims 1 to 5, characterized in that the electronic component (3) is attached on the circuit board (2) with contact or connection sites (5) oriented away from the circuit board (2), and is overlaid by the intermediate layer (4) for disentanglement and connection to the contact or connection surfaces (8) of the circuit board (2). 7. A process for producing an intermediate layer (4) for disentangling contact or connection sites (5) of an electronic component (3) from contact or connection surfaces (8) of a circuit board (2), characterized by the steps of: - providing the circuit board (2) with a plurality of contact or connection surfaces (8); - forming a base material of the intermediate layer (4) at least in the region of the contact or connection surfaces (8) of the circuit board (2); - structuring the intermediate layer (4) to form conductive tracks or structures (9) and contact sites (6, 7) for contacting with contact or connection surfaces (8) of the circuit board (2) and with contact or connection sites (5) of an electronic component (3) to be attached on the circuit board (2). 8. A process according to claim 7, characterized in that the structuring of the intermediate layer (4) is performed by subtractive techniques, semi-additive techniques, additive techniques and/or embossing techniques or laser structuring techniques known per se. 9. A process according to claim 7 or 8, characterized in that, after the structuring of the intermediate layer (4), an additional support layer (11) for the attachment or contacting of the electronic component (3) is applied on the intermediate layer (4) for disentanglement and provided with contacts (10) for the electronic component (3). 10. A process according to claim 7, 8 or 9, characterized in that the intermediate layer (4) is formed with a thickness reduced relative to the thickness of a circuit board layer. 11. A process according to claim 10, characterized in that the thickness of the intermediate layer (4) is selected to be less than half, in particular less than a third, of the thickness of a circuit board layer. 12. A process according to any one of claims 7 to 11, characterized in that the intermediate layer (4) is provided with conductive tracks or conductive structures (9) whose widths are selected to be less than 50 μm, in particular less than 3 0 μm. 13. A process according to any one of claims 7 to 11, characterized in that the intermediate layer (4) is used as a support, and/or enclosure for the electronic component (3). 14. A system including a circuit board (2) and at least one electronic component (3), characterized in that at least one intermediate layer (4) for the disentanglement of contact or connection sites (5) of the electronic component (3) from contact or connection surfaces (8) of the circuit board (2) is arranged or formed between the contact or connection sites (5) of the electronic component (3) and the contact or connection surfaces (8) of the circuit board (2) , and that the contact or connection sites (5) of the electronic component (3) comprise mutual distances reduced relative to the contact or connection sites (8) of the circuit board (2). 15. A system according to claim 14, characterized in that the intermediate layer (4) is formed with conductive tracks or structures (9) between contact zones (6, 7) corresponding to the contact or connection sites (5) of the electronic component (3) and corresponding to the contact or connection surfaces (8) of the circuit board (2). 16. A system according to claim 14 or 15, characterized in that an additional support layer (11) for the attachment and contacting of the electronic component (3) is applied on the intermediate layer (4) for disentanglement and provided with contacts (10) for the electronic component (3) . 17. A system according to claim 14, 15 or 16, characterized in that the intermediate layer (4) is formed with a thickness reduced relative to the thickness of a circuit board layer. 18. A system according to claim 17, characterized in that the thickness of the intermediate layer (4) amounts to less than half, in particular less than a third, of the thickness of a circuit board layer. 19. A system according to any one of claims 14 to 18, characterized in that the intermediate layer is provided with conductive tracks or conductive structures (9) whose widths are less than 50 μm, in particular less than 30 μm. 20. A system according to any one of claims 14 to 19, characterized in that the intermediate layer (4) is used as a support and/or enclosure for the electronic component (3). 21. A system according to any one of claims 14 to 20, characterized in that the circuit board (2) in a manner known per se is formed with a plurality of superimposed circuit board layers which are at least partially interconnected by conductive passages or microvias connecting individual circuit board layers. In a method for fixing an electronic component (3) on a printed circuit board (2), and contact-connecting the electronic component (3) to the printed circuit board (2), the following steps are provided: - providing the printed circuit board (2) having a plurality of contact and connection pads (8), - providing the electronic component (3) having a number of contact and connection locations (5) corresponding to the plurality of contact and connection pads (8) of the printed circuit board (2), with a mutual spacing reduced in comparison with the spacing of the contact and connection pads (8) of the printed circuit board (2), and - arranging or forming at least one interlayer (4) for routing the contact and connection locations (5) of the electronic component (3) between the contact and connection pads (8) of the printed circuit board (2) and the contact and connection locations (5) of the electronic component (3). A method for producing an interlayer (4) for routing and a system having a printed circuit board (2) and an electronic component (3) using the interlayer (4) for routing are also provided.

Full Text

METHOD FOR FIXING AN ELECTRONIC COMPONENT ON A PRINTED
CIRCUIT BOARD AND SYSTEM COMPRISING A PRINTED CIRCUIT BOARD
AND AT LEAST ONE ELECTRONIC COMPONENT
The present invention relates to a process for attaching or
fixing an electronic component on a circuit board and/or
contacting the electronic component with the circuit board,
as well as a process for producing an intermediate layer
for disentangling contact or connection sites of an
electronic component from contact or connection surfaces of
a circuit board. The present invention further relates to a
system including a circuit board and at least one
electronic component.
Electronic components to be applied on circuit boards have
become increasingly complex, which has, above all, resulted
in an increase of the required number of connections to the
circuit board, which has in turn led to a reduction of the
distances between individual or neighboring connections
such as, for instance, conductive pins with an unchanged
size of the electronic component. In this connection,
printed circuit board manufacturers started to perform
disentanglements of such components, or individual
components, via conductive passages or microvias through
several circuit board layers in so-called high-density
interconnects or HDI boards or printed boards.
With a further increase in the complexity of electronic
components and the thus involved increase in the number of
connections to a circuit board, and/or a further reduction
of the dimensions of such electronic components, which will
likewise lead to reduced distances between neighboring
connections, a large increase in the number of circuit

board layers is expected for the necessary disentanglement.
Moreover, an increase in the complexity of such an
electronic component together with reduced mutual distances
linked with enhanced connections will minimize the options
for realizing or arranging conductive tracks or conductive
structures between individual connections, or render an
arrangement impossible at all, which will immediately call
for a further increase in the number of necessary circuit
board layers. Additional layers of such a circuit board
will, however, result in an increased thickness of the
circuit board and, moreover, in increased production costs.
A way of reducing the number of circuit boards is by using
very fine or ultra-fine conductive structures, wherein,
however, for the time being, even with the possible
availability of processes for producing such fine or ultra-
fine conductive structures, it is to be anticipated that
the production of multilayer circuit boards including such
ultra-fine conductive structures in usual production
formats of high-density interconnects, such as, e.g., 18 x
24 inch, does not enable the orientation of circuit board
layers with sufficient precision in order to, for instance,
provide conductive connections between individual board
layers where such ultra-fine conductive tracks or
conductive structures are provided.
From WO 01/43190 Al there has become known a liquid crystal
display, wherein a substrate having connecting or contact
surfaces is coupled or connected with an electronic
component by using an intermediate device.
From US 2005/0133891 Al there has become known a system
consisting of a circuit board or printed circuit board and

an electronic component, wherein the electronic component
is coupled with the circuit board or the substrate via
intermediate connecting locations. Moreover, from US
6,429,534 Bl there can be taken a frame-like element for
coupling a circuit board and an electronic component to be
fixed on the circuit board, wherein the frame-like element
surrounds the electronic component being fixed on the
circuit board and a coupling is provided between the
connecting locations or sites of the electronic component
facing away from the circuit board and respective
connecting or contact surfaces of the circuit board by wire
connections, which are provided between the connecting or
contact surfaces of the electronic component and respective
wiring paths or tracks on the frame-like element on the one
side and between the wiring paths on the frame-like element
and the respective contact surfaces of the circuit board on
the other hand, so that much effort is necessary for
coupling the connecting areas of the electronic component
with respective or dedicated connecting areas of the
circuit board by arranging a very large number of wire
connections.
Based on a process of the initially defined kind as well as
a system of the initially defined kind, the present
invention, therefore, aims to avoid the above-mentioned
problems with regard to the use of electronic components of
increased complexity and/or reduced size, and hence the
reduction of the small mutual distances between connections
to the circuit board, by a substantially unchanged circuit
board design and, in particular, to enable the
disentanglement of such highly complex components of, in
particular, small dimensions while avoiding additionally
required circuit board layers.

To achieve the above-mentioned objects, a process for
attaching or fixing an electronic component on a circuit
board and/or contacting the electronic component with the
circuit board is essentially characterized by the steps of:
- providing the circuit board with a plurality of contact
or connection surfaces;
- providing the electronic component with a number of
contact or connection sites corresponding to the plurality
of contact or connection surfaces of the circuit board, at
mutual distances reduced relative to the distances of the
contact or connection surfaces of the circuit board; and
- arranging or forming between the contact or connection
surfaces of the circuit board and the contact or connection
sites of the electronic component at least one intermediate
layer for disentangling the contact or connection sites of
the electronic component.
Due to the fact that according to the invention, after
having provided the circuit board or printed circuit board
with a plurality of contact or connection surfaces and the
electronic component with a corresponding number of contact
or connection sites, an or at least one intermediate layer
for disentangling the contact or connection sites of the
electronic component is arranged or formed between the
contact or connection surfaces of the circuit board and the
associated contact or connection sites of the electronic
component, it has become feasible to couple with, or attach
to, the circuit board, or contact the latter with, an
electronic component comprising an optionally higher
complexity and, consequently, a larger number of
connections to the circuit board at simultaneously reduced
distances between the individual connections, and/or an

electronic component having reduced dimensions, without
increasing the number of circuit board layers for the
disentanglement between the connection sites of the
electronic component and the connection sites or surfaces
of the circuit board. The intermediate layer provided
according to the invention may have a thickness reduced
relative to the thickness of a circuit board layer,
particularly of the dielectric layer or film, such that a
negligible increase in the thickness of the entire circuit
board will do, particularly in consideration of the fact
that a circuit board of this type would usually comprise a
plurality of, for instance, more than 4 and, in particular,
more than 6 circuit board layers, while, at the same time,
enabling the safe disentanglement in a preferably single
layer or ply of the intermediate layer. If highly complex
components including extremely large numbers of contact or
connection sites are employed, more than one intermediate
layer including the respective feedthroughs may be
provided, wherein, however, even with the provision of more
than one intermediate layer, unalteredly great advantages
relative to the provision of an elevated number of
additional board layers will be attainable, bearing in mind
the strongly reduced thickness as compared to conventional
circuit boards and the simplified structuring of the
circuit board.
It is, thus, feasible to resort to presently available
techniques for forming circuit boards having a plurality of
circuit board layers, in particular when taking into
account the precision requirements for the alignment of
individual subregions of such circuit board layers, while
the appropriate, very fine or ultra-fine conductive tracks
or structures may be provided in the region of the

intermediate layer for disentanglement, while accordingly-
large partial regions or contact zones may be provided on
the intermediate layer for the respective contacting or
connection of the contact or connection sites of the
electronic component as well as the connection or contact
surfaces of the circuit boards.
As already indicated above, it will do for disentanglement
to use an intermediate layer having a simplified structure
as compared to usual circuit board layers, it being
preferably proposed in this respect that the intermediate
layer is formed with conductive tracks or structures
between contact zones corresponding to the contact or
connection sites of the electronic component and
corresponding to the contact or connection surfaces of the
circuit board. Since the intermediate layer is merely
formed with conductive tracks or structures between contact
zones corresponding to the contact or connection sites of
the electronic component and corresponding to the contact
or connection surfaces of the circuit board, the
arrangement or formation of very fine or ultra-fine
conductive tracks or structures may be provided, which can,
for instance, be formed by known techniques on or in the
intermediate layer such that the mutual distances of the
connections of such components, which are reduced when
using complex components, do not constitute any restriction
in view of the possibility of realizing or providing
conductive tracks in the intermediate layer.
In order to ensure reliable contacting between the
electronic component and the intermediate layer for
disentanglement, it is proposed according to a preferred
embodiment that contacting between the contact or

connection sites of the electronic component and the
intermediate layer is realized via contacts of the
electronic component.
According to a modified embodiment, it is preferably-
proposed by the invention that contact or connection sites
of the electronic component are directly contacted with
contact zones of the intermediate layer, thus enabling a
further reduction of costs for the attachment of the
electronic component to the circuit board, and also an
improved connection or fixation of electronic components on
a circuit board while interposing the intermediate layer
for disentanglement, by a reduction of connections, for
instance welds or bonds.
According to a further preferred embodiment, it is proposed
that the intermediate layer is merely formed in the region
of the contact or connection surfaces of the circuit board
as well as the contact or connection sites of the
electronic component, so that accordingly reduced material
expenditures will be involved in the formation of the
intermediate layer, since the latter merely need be
provided in the region of the attachment of the or an
electronic component on the circuit board while, at the
same time, taking into account the increased distances
between the individual contact or connection surfaces of
the circuit board relative to the distances of the contact
or connection sites of the electronic component.
For a further cost reduction and/or formation of a compact
overall structure, in particular when assembling the
electronic component and the circuit board, it is proposed
according to a further preferred embodiment that the

electronic component is attached on the circuit board with
contact or connection surfaces oriented away from the
circuit board, and is overlaid by the intermediate layer
for disentanglement and connection to the contact or
connection surfaces of the circuit board. Thus, in addition
to offering the chance of disentanglement via the
intermediate layer having an extremely small thickness,
also a supporting function for the electronic component
will be fulfilled such that an additional carrier substrate
for the electronic component will be obviated so as to not
only enable a reduction of the size of the overall system
comprised of the circuit board and the at least one
electronic component, but also a reduction of the overall
costs.
To achieve the objects mentioned in the beginning, a
process for producing an intermediate layer for
disentangling contact or connection sites of an electronic
component from contact or connection surfaces of a circuit
board is, moreover, essentially characterized by the steps
of:
- providing the circuit board with a plurality of contact
or connection surfaces;
- forming a base material of the intermediate layer at
least in the region of the contact or connection surfaces
of the circuit board;
structuring the intermediate layer to form conductive
tracks or structures and contact sites for contacting with
contact or connection surfaces of the circuit board and
with contact or connection sites of an electronic component
to be attached on the circuit board.

As already pointed out above, it is feasible in a simple
manner, after having provided the circuit board with a
plurality of contact or connection sites, to make the at
least one intermediate layer for disentanglement available
for an electronic component to be subsequently attached.
For a reliable formation of the intermediate layer
comprising, in particular, very fine or ultra-fine
conductive tracks or structures, it is, moreover, proposed
that the structuring of the intermediate layer is performed
by subtractive techniques, semi-additive techniques,
additive techniques and/or embossing techniques or laser
structuring techniques known per se, as in correspondence
with a preferred embodiment of the process for producing
the intermediate layer for disentanglement according to the
invention.
For receiving, or fulfilling the function of a support for,
an electronic component to be subsequently attached to the
circuit board upon interposition of the intermediate layer
for disentanglement, it is proposed according to a further
preferred embodiment that, after the structuring of the
intermediate layer, an additional support layer for the
attachment or contacting of the electronic component is
applied on the intermediate layer for disentanglement and
provided with contacts for the electronic component.
As already mentioned above, it may preferably be provided
according to the invention, particularly in consideration
of the fact that the intermediate layer for disentanglement
merely contains very fine or ultra-fine conductive tracks
or structures in addition to the contact zones to be
provided for contacting with the electronic component as

well as the circuit board, that the intermediate layer is
formed with a thickness reduced- relative to the thickness
of a circuit board layer.
In this connection, it is proposed according to a
particularly preferred embodiment that the thickness of the
intermediate layer is selected to be less than half, in
particular less than a third, of the thickness of a circuit
board layer. It is, thus, feasible to do, for instance,
with intermediate layers having dielectric film thicknesses
of below, e.g. 35 to 40 μm, in particular down to 10 μm or
less, while a typical dielectric film thickness of an HDI
circuit board amounts to at least 60 μm, e.g. more than 80
μm.
For the disentanglement of the junction, or contact or
connection sites of the electronic component, very fine or
ultra-fine conductive structures will do in the
intermediate layer, wherein it is proposed in this respect
according to a further preferred embodiment that the
intermediate layer is provided with conductive tracks or
conductive structures whose widths are selected to be less
than 50 μm, in particular less than 30 μm.
As already indicated above, it is feasible according to a
further preferred embodiment, in particular with a view to
further reducing costs and simplifying the formation and
attachment of the electronic component, that the
intermediate layer is used as a support and/or enclosure
for the electronic component.
To achieve the initially mentioned objects, a system
including a circuit board and at least one electronic

component, moreover, is essentially characterized in that
at least one intermediate layer for the disentanglement of
contact or connection sites of the electronic component
from contact or connection surfaces of the circuit board is
arranged or formed between the contact or connection sites
of the electronic component and the contact or connection
surfaces of the circuit board, and that the contact or
connection sites of the electronic component comprise
mutual distances reduced relative to the contact or
connection sites of the circuit board. It is, thus,
feasible to ensure disentanglement merely by providing at
least one intermediate layer having a comparatively small
thickness, said intermediate layer being preferably
provided or providable merely partially in the region of
the contact or connection surfaces of the circuit board and
of the contact or connection sites of the electronic
component to be connected therewith, as already indicated
above.
According to a preferred embodiment, it is proposed in this
respect that the intermediate layer is formed with
conductive tracks or structures between contact zones
corresponding to the contact or connection sites of the
electronic component and corresponding to the contact or
connection surfaces of the circuit board.
To simplify the attachment and contacting of the electronic
component, it is, moreover, proposed that an additional
support layer for the attachment and contacting of the
electronic component is applied on the intermediate layer
for disentanglement and provided with contacts for the
electronic component, as in correspondence with a further

preferred embodiment of the system according to the
invention.
As already indicated several times, it may preferably be
provided that the intermediate layer is formed with a
thickness reduced relative to the thickness of a circuit
board layer, wherein it is proposed according a
particularly preferred embodiment that the thickness of the
intermediate layer is less than half, in particular less
than a third, of the thickness of a circuit board layer.
In addition, it is preferably proposed that the
intermediate layer is provided with conductive tracks or
conductive structures whose widths are less than 50 μm, in
particular less than 30 μm.
For the use of unpackaged electronic components and in
order to facilitate the attachment to a circuit board and
contacting with the same, it is proposed according to a
further preferred embodiment that the intermediate layer is
used as a support and/or enclosure for the electronic
component.
As already indicated several times, the intermediate layer
for disentanglement according to the invention is
preferably usable, in particular, in connection with a
circuit board having a plurality of circuit board layers,
wherein it is, moreover, proposed that the circuit board in
a manner known per se is formed with a plurality of
superimposed circuit board layers which are at least
partially interconnected by conductive passages or
microvias connecting individual circuit board layers, as in

correspondence with a further preferred embodiment of the
system according to the invention.
In the following, the invention will be explained in more
detail by way of exemplary embodiments schematically
illustrated in the accompanying drawing. Therein:
Fig. 1 is a partial section through a system according to
the invention, which is comprised of a circuit board and an
electronic component attached thereto, using an
intermediate layer according to the invention for
disentanglement;
Fig. 2 schematically illustrates individual steps for
carrying out the process according to the invention for
attaching an electronic component to a circuit board while
forming or arranging an intermediate layer for
disentanglement;
Fig. 3 schematically illustrates individual process steps
for forming an intermediate layer for disentanglement to be
used in the process according to the invention and in the
system according to the invention, respectively;
Fig. 4, in an illustration similar to that of Fig. 1,
depicts in detail an electronic component of a system
according to the invention, on a scale reduced relative to
that of Fig. 1;
Fig. 5, in an illustration similar to that of Fig. 4,
depicts a further modified embodiment of a system according
to the invention, with an unpackaged electronic component
being integrated;
Fig. 6, in an illustration similar to those of Figs. 4 and
5, depicts a further modified embodiment of a system
according to the invention, with the electronic component
being directly applied on the intermediate layer for
disentanglement; and

Fig. 7, in an illustration again similar to those of Figs.
4 to 6, depicts a further modified embodiment of the system
according to the invention, with the intermediate layer for
disentanglement being applied on a component integrated in
the circuit board.
Fig. 1 schematically illustrates a system 1 which is
comprised of a printed circuit board, in particular an HDI
board 2 having a plurality of board layers, and an
electronic component 3 to be contacted with, and attached
to, the former with an intermediate layer 4 for
disentanglement arranged between the electronic component 3
and the circuit board 2.
As is apparent from Fig. 1, the intermediate layer 4
comprises a plurality of contact or connection zones 6
corresponding to the number of contact or connection sites
5 of the electronic component 3, which contact or
connection zones 6 are either substantially directly
coupled with contact or connection zones 7 corresponding to
contact or connection surfaces 8 provided on the circuit
board 2. From Fig. 1, it is apparent that the distances
between neighboring contact or connection sites 5 of the
electronic component 3 are smaller than the distances
between neighboring contact or connection surfaces 8 of the
circuit board 2 such that, for a disentanglement in the
intermediate layer 4, very fine or ultra-fine conductive
tracks or conductive structures are additionally included
to provide connections with further contact or connection
zones 7 of the intermediate layer 4, via which contacting
with connection or contact surfaces 8 of the circuit board
2 is subsequently effected.

As opposed to the known prior art, where immediate
contacting between the connection or contact sites or
connections 5 of the electronic component 3 with the
associated connection or contact surfaces 8 of the circuit
board 2 is realized, optionally by providing conductive
passages or microvias for the disentanglement of the
connection or contact sites 5 of the highly complex
electronic component 3, the configuration according to Fig.
1 ensures complete disentanglement via the intermediate
layer 4.
In the configuration according to Fig. 1, the intermediate
layer 4 for disentanglement is merely provided in the
region of the contact or connection sites 5 of the
electronic component 3 as well as the connection or contact
surfaces 7 of the circuit board 2 such that a partial
formation of the intermediate layer 4 will do.
Moreover, the thickness of the intermediate layer is not
represented to scale relative to the size or dimensions of
both the circuit board 2 and the electronic component 3 in
any of the Figures. Taking into account the very fine or
ultra-fine conductive tracks or conductive structures 9,
which may, for instance, have widths of less than 50 μm,
e.g. about 25 μm, a thickness of the dielectric film for
the intermediate layer 4 in the order of about 35 μm will
do, this being less than half of the usual thickness of the
dielectric film of a board layer of a circuit board 2.
Moreover, thicknesses for the dielectric film of the
intermediate layer 4 of up to 10 μm or therebelow are
usable or applicable.

The circuit board 2 illustrated in the Figures is,
moreover, for instance, comprised of a plurality of circuit
board layers, which are, however, not illustrated or
indicated separately.
In the embodiment represented in Fig. 1, contacting between
the intermediate layer 4 for disentanglement and the
connection or contact sites 5 of the component 3 is
realized via conductive contacts 10, which are received or
provided in a carrier layer or support structure
schematically indicated by 11.
Instead of the merely partial arrangement of the
intermediate layer 4 for disentanglement in correspondence
with the contact or connection surfaces 8 of the circuit
board 2 as well as the contact or connection sites 5 of the
electronic component 3, the intermediate layer 4 and, in
particular, the base material of the same may be applied or
provided substantially all-over the surface of the circuit
board 2, the respective structuring with the contact zones
6 and 7, respectively, as well as the conductive tracks 9
being merely provided or formed in the region of the
attachment or contacting of the or an electronic component
3 on the circuit board 2.
Fig. 2 schematically depicts a process sequence for
producing a system 1 comprised of a circuit board and an
electronic component, while using or forming an
intermediate layer 4 for disentanglement.
In step (a), a circuit board, in particular a HDI board 2,
is provided, wherein appropriate connection or contact
surfaces 8 are already formed and indicated.

In step (b), a base material for the intermediate layer 4
is applied, whereupon in step (c) the structuring of the
contact or connection zones 6 and 7, respectively, as well
as the conductive tracks 9 of the intermediate layer 4 is
performed, an exemplary process for structuring the
intermediate layer 4 being discussed below with reference
to Fig. 3.
Following the structuring or formation of the intermediate
layer 4 for disentanglement, the application of additional
plies or support layers 11 and 12 is effected in step (d),
whereupon, according to step (e), the structuring and
finishing of the support layers or plies 11 and 12 is
carried out, for instance by providing contacts 10.
Finally, in step (f), the electronic component 3 is coupled
or connected to the intermediate layer 4 for
disentanglement, and subsequently with the circuit board 2,
via the connection or contact sites 5, while interposing
contacts 10.
Fig. 3 schematically illustrates the partial steps of a
process for structuring or forming an intermediate layer 4,
using, for instance, an embossing technique known per se.
It should further be noted that, for the formation or
structuring of the intermediate layer 4 for
disentanglement, structuring is merely performed on just
one side as opposed to the double-sided structuring of an
extremely fine conductor structure generally indicated in
Fig. 3.

In step (a) according to Fig. 3, embossing of the
intermediate layer 4 is carried out using, for instance, an
embossing tool 13 to emboss a relief structure on a thermo-
plastic foil.
In step (b), possibly remaining residual materials are, for
instance, removed by reactive ion etching in order to
enable the production of throughgoing holes or microvias
14, whereupon, according to step (c), the application of a
seed layer of a thin, conductive material is realized over
the entire surface. Such an application may, for instance,
be effected by sputtering or thermal vapor deposition.
After this, the relief structure is coppered according to
step (d), and the projecting copper built up by the
galvanization process is removed in step (e), for instance
by chemical or mechanical processes, so as to enable, as a
function of the desired structure of the intermediate layer
4, the formation of contact zones 6 and 7 according to the
positions of the contact or connection sites 5 of the
electronic component 3 and the contact or connection
surfaces 8 of the circuit board 2 as well as the required
ultra-fine conductive tracks 9.
For the production of the intermediate layer 4,
thermoplastic materials like, e.g., polyetherimide, liquid
crystal polymer (LCP) may be used.
Alternatively to the use of thermoplastic materials,
thermally or UV-curable materials may be employed for the
structuring of the intermediate layer 4.

Furthermore, the application of a conductive layer
described in steps (c) and (d) may be replaced with the
filling of the depressions or recesses with a conductive
material.
Instead of using an embossing technique, the removal of the
polymer material used for the intermediate layer 4 may, for
instance, be done by the aid of laser light.
For the structuring of the circuit board or the arrangement
of the conductive connection or contact zones 6 and 7,
respectively, as well as the conductive tracks 9, known
subtractive techniques, semi-additive techniques or
additive techniques may, moreover, be employed.
In the exemplary embodiments illustrated in Figs. 4 to 7,
the reference numerals of the preceding Figures, in
particular those of Fig. 1, have been retained for
identical components.
According to the illustration of Fig. 4, the attachment of
the electronic component 3 is again realized via contacts
10 on the intermediate layer 4 for contacting with the
circuit board 2, wherein Fig. 4, in addition, depicts the
electronic component 3 in greater detail, from which it is,
in particular, apparent that the latter is arranged on a
plate-shaped support structure 15 and surrounded by a
sheathing 16.
From the modified illustration according to Fig. 5, it is
apparent that an electronic component again denoted by 3 is
inserted without the support structure and sheathing
structure 15 and 16, respectively, illustrated in Fig. 4,

but is directly connected or coupled, via connection or
contact sites again denoted by 5, with the respective
contact zones 6 of the intermediate layer 4 for
disentanglement, via which a connection or junction to the
circuit board again denoted by 2 is subsequently realized
via the connection or contact surfaces 8.
In the configuration according to Fig. 5, the intermediate
layer 4 for disentanglement, moreover, serves directly as a
support structure and, hence, fulfils a supporting or
carrying function for the electronic component 3 such that
additional contacts may be obviated. This results in a
reduction of costs and, at the same time, an enhanced
connection of the electronic component 3 to the
intermediate layer 4 and, hence, to the circuit board 2.
For the proper fixation and protection of the unpackaged
component 3, a sheathing 17 surrounding the electronic
component 3 and supported on the intermediate layer 4 for
disentanglement is indicated in the embodiment according to
Fig. 5.
In the embodiment according to Fig. 6, an unpackaged
electronic component 3 is employed, which is directly
coupled with the intermediate layer 4 for disentanglement.
Further layers 18 and 19 are indicated above the component
3, wherein, in particular in the region of these layers,
additional contacts or connections 20 are indicated, which
serve for the attachment of further components not shown in
Fig. 6. The contacting of such further components via the
connections or contacts 20 in the embodiment illustrated in
Fig. 6 is again realized upon interposition of the
intermediate layer 4 for disentanglement.

In the embodiment represented in Fig. 7, the electronic
component 3 is arranged with the connection or contact
sites facing away from the circuit board 2, the
intermediate layer 4 for disentanglement being arranged
above the electronic component 3 and subsequent contacting
being again effected with connection or contact surfaces 8
of the circuit board 2. In the embodiments according to
Figs. 6 and 7, an integration of the electronic component 3
is, thus, immediately enabled, this resulting in a further
integration of embedded components and an increased
compactness at the simultaneous reduction of the overall
size of the system.
By using the intermediate layer 4 for disentanglement
between the connection or contact sites 5 of the electronic
component 3 and also the contact or connection surfaces 8
of the circuit board 2, an intermediate layer 4 having a
reduced thickness, in particular in respect to the
dielectric layer, particularly as compared to the thickness
of usual circuit board layers, will thus, be enough such
that, in the main, only a negligible increase in the
thickness of the overall circuit board will occur.
Furthermox-e, a single intermediate layer 4 for
disentanglement will do in most cases, said intermediate
layer 4, as opposed to usual circuit board layers, for
disentanglement only comprising contact zones 6 and 7 as
well as very fine or ultra-fine conductive tracks or
conductive structures 9 which are adaptable to the small
distances of connections or connection sites 5 of highly
complex electronic components 3, without requiring a
plurality of layers and, in particular, additional circuit

board layers for the disentanglement of such highly complex
components 3.
When using electronic components 3 comprising extremely
large numbers of connection or contact sites, whose number
may range from some hundreds to some thousands, it may,
moreover, be provided that a further intermediate layer is
applied or deposited on an intermediate layer 4, for
instance according to the process schematically illustrated
in Fig. 3, wherein appropriate feedthroughs or microvias
are provided for contacting with the circuit board 2
arranged therebelow, or the circuit board layers forming
the circuit board 2. Bearing in mind the fact that the
thickness of such an optionally required, additional
intermediate layer 4 is again strongly reduced as compared
to the thickness of an additional circuit board layer and,
in particular, its dielectric layer, and further bearing in
mind that, due to the simplified structuring of such an
intermediate layer 4 for disentanglement, the latter
substantially comprises but very fine or ultra-fine
conductive track structures 9, a negligible increase in the
overall thickness of the circuit board 2 along with the
intermediate layers 4 will do even if more than one
intermediate layer 4 is provided for disentanglement in the
region of highly complex components 3. By contrast, it will
have to be taken into account that, with an optionally
sought disentanglement via additional circuit board layers,
the number of circuit board layers will have to be
considerably increased on account of the more complex
structures of the latter as compared to the simple
structure, of the intermediate layer 4 such that an
accordingly high increase in the overall thickness of the

circuit board 2 as well as the production costs will be
involved.
In addition, the arrangement of the thin intermediate layer
4 renders feasible the provision of larger connection sites
or zones so as to meet the requirements of a registering
accuracy of the individual layers even when using large-
sized production formats of printed circuit boards and, in
particular, HDI boards. The tapering or conically shaped
bores provided in the region of passages will require
little space considering the thickness reduction, thus
lowering the requirements of a registration or orientation
accuracy.

Claims
1. A process for attaching an electronic component (3) on a
circuit board (2) and/or contacting the electronic
component (3) with the circuit board (2), characterized by
the steps of:
- providing the circuit board (2) with a plurality of
contact or connection surfaces (8);
- providing the electronic component (3) with a number of
contact or connection sites (5) corresponding to the
plurality of contact or connection surfaces (8) of the
circuit board, at mutual distances reduced relative to the
distances of the contact or connection surfaces (8) of the
circuit board (2); and
- arranging or forming between the contact or connection
surfaces (8) of the circuit board (2) and the contact or
connection sites (5) of the electronic component (3) at
least one intermediate layer (4) for disentangling the
contact or connection sites (5) of the electronic component
(3) .
2. A process according to claim 1, characterized in that
the intermediate layer (4) is formed with conductive tracks
or structures (9) between contact zones corresponding to
the contact or connection sites (5) of the electronic
component (3) and corresponding to the contact or
connection surfaces (8) of the circuit board (2).
3. A process according to claim 1 or 2, characterized in
that contacting between the contact or connection sites (5)
of the electronic component (3) and the intermediate layer
(4) is effected via contacts of the electronic component
(3).

4. A process according to claim 1 or 2, characterized in
that contact or connection sites (5) of the electronic
component (3) are directly contacted with contact zones of
the intermediate layer (4).
5. A process according to any one of claims 1 to 4,
characterized in that the intermediate layer (4) is merely
formed in the region of the contact or connection surfaces
(8) of the circuit board (2) as well as the contact or
connection sites (5) of the electronic component (3).
6. A process according to any one of claims 1 to 5,
characterized in that the electronic component (3) is
attached on the circuit board (2) with contact or
connection sites (5) oriented away from the circuit board
(2), and is overlaid by the intermediate layer (4) for
disentanglement and connection to the contact or connection
surfaces (8) of the circuit board (2).
7. A process for producing an intermediate layer (4) for
disentangling contact or connection sites (5) of an
electronic component (3) from contact or connection
surfaces (8) of a circuit board (2), characterized by the
steps of:
- providing the circuit board (2) with a plurality of
contact or connection surfaces (8);
- forming a base material of the intermediate layer (4) at
least in the region of the contact or connection surfaces
(8) of the circuit board (2);
- structuring the intermediate layer (4) to form conductive
tracks or structures (9) and contact sites (6, 7) for
contacting with contact or connection surfaces (8) of the

circuit board (2) and with contact or connection sites (5)
of an electronic component (3) to be attached on the
circuit board (2).
8. A process according to claim 7, characterized in that
the structuring of the intermediate layer (4) is performed
by subtractive techniques, semi-additive techniques,
additive techniques and/or embossing techniques or laser
structuring techniques known per se.
9. A process according to claim 7 or 8, characterized in
that, after the structuring of the intermediate layer (4),
an additional support layer (11) for the attachment or
contacting of the electronic component (3) is applied on
the intermediate layer (4) for disentanglement and provided
with contacts (10) for the electronic component (3).

10. A process according to claim 7, 8 or 9, characterized
in that the intermediate layer (4) is formed with a
thickness reduced relative to the thickness of a circuit
board layer.
11. A process according to claim 10, characterized in that
the thickness of the intermediate layer (4) is selected to
be less than half, in particular less than a third, of the
thickness of a circuit board layer.
12. A process according to any one of claims 7 to 11,
characterized in that the intermediate layer (4) is
provided with conductive tracks or conductive structures
(9) whose widths are selected to be less than 50 μm, in
particular less than 3 0 μm.

13. A process according to any one of claims 7 to 11,
characterized in that the intermediate layer (4) is used as
a support, and/or enclosure for the electronic component
(3).
14. A system including a circuit board (2) and at least one
electronic component (3), characterized in that at least
one intermediate layer (4) for the disentanglement of
contact or connection sites (5) of the electronic component
(3) from contact or connection surfaces (8) of the circuit
board (2) is arranged or formed between the contact or
connection sites (5) of the electronic component (3) and
the contact or connection surfaces (8) of the circuit board
(2) , and that the contact or connection sites (5) of the
electronic component (3) comprise mutual distances reduced
relative to the contact or connection sites (8) of the
circuit board (2).
15. A system according to claim 14, characterized in that
the intermediate layer (4) is formed with conductive tracks
or structures (9) between contact zones (6, 7)
corresponding to the contact or connection sites (5) of the
electronic component (3) and corresponding to the contact
or connection surfaces (8) of the circuit board (2).
16. A system according to claim 14 or 15, characterized in
that an additional support layer (11) for the attachment
and contacting of the electronic component (3) is applied
on the intermediate layer (4) for disentanglement and
provided with contacts (10) for the electronic component
(3) .

17. A system according to claim 14, 15 or 16, characterized
in that the intermediate layer (4) is formed with a
thickness reduced relative to the thickness of a circuit
board layer.
18. A system according to claim 17, characterized in that
the thickness of the intermediate layer (4) amounts to less
than half, in particular less than a third, of the
thickness of a circuit board layer.

19. A system according to any one of claims 14 to 18,
characterized in that the intermediate layer is provided
with conductive tracks or conductive structures (9) whose
widths are less than 50 μm, in particular less than 30 μm.
20. A system according to any one of claims 14 to 19,
characterized in that the intermediate layer (4) is used as
a support and/or enclosure for the electronic component
(3).
21. A system according to any one of claims 14 to 20,
characterized in that the circuit board (2) in a manner
known per se is formed with a plurality of superimposed
circuit board layers which are at least partially
interconnected by conductive passages or microvias
connecting individual circuit board layers.

In a method for fixing an electronic component (3) on a
printed circuit board (2), and contact-connecting the
electronic component (3) to the printed circuit board (2),
the following steps are provided: - providing the printed
circuit board (2) having a plurality of contact and
connection pads (8), - providing the electronic component
(3) having a number of contact and connection locations (5)
corresponding to the plurality of contact and connection
pads (8) of the printed circuit board (2), with a mutual
spacing reduced in comparison with the spacing of the
contact and connection pads (8) of the printed circuit
board (2), and - arranging or forming at least one
interlayer (4) for routing the contact and connection
locations (5) of the electronic component (3) between the
contact and connection pads (8) of the printed circuit
board (2) and the contact and connection locations (5) of
the electronic component (3). A method for producing an
interlayer (4) for routing and a system having a printed
circuit board (2) and an electronic component (3) using the
interlayer (4) for routing are also provided.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=n+ckdOGnkv7exeUMu1UxLA==&loc=wDBSZCsAt7zoiVrqcFJsRw==

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Patent Number

271929

Indian Patent Application Number

4583/KOLNP/2008

PG Journal Number

11/2016

Publication Date

11-Mar-2016

Grant Date

10-Mar-2016

Date of Filing

12-Nov-2008

Name of Patentee

AT & S AUSTRIA TECHNOLOGIE & SYSTEMTECHNIK AKTIENGESELLSCHAFT

Applicant Address

FABRIKGASSE 13, 8700 LEOBEN-HINTERBERG

Inventors:

#	Inventor's Name	Inventor's Address
1	GERHARD SCHMID	IN DER TULL 13, 8793 TROFAIACH
2	HANNES VORABERGER	EICHENHAINGASSE 11E, 8045 GRAZ
3	MARKUS RIESTER	HUMMELBERGWEG 8, 8054 SEIERSBERG
4	JOHANNES STAHR	MURPARK 1, 8600 BRUCK

PCT International Classification Number

H01L 23/498

PCT International Application Number

PCT/AT2007/000234

PCT International Filing date

2007-05-15

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	GM 393/2006	2006-05-16	Austria