DE19963850A1 - Method and device for producing a conductive structure on a substrate - Google Patents

Abstract

The invention relates to a method and to a device for producing a conductive structure (8) on a substrate (10) by means of a transfer/transmission method. According to the inventive method, first a metal layer is chemically or electrochemically deposited on a structured metal layer (6) in a selective manner so as to produce a conductive structure, said structured metal layer being provided on a reusable support (2). The conductive structure (8) produced is transferred to the substrate (10) and the reusable support (2) is separated from the substrate (10).

Description

The present invention relates to methods and Devices for producing conductive structures a substrate or on a circuit carrier.

Different manufacturing processes currently exist development of conductor tracks, which are basically two basic Have steps, namely the application of a conductive Material on a substrate and the structuring of the same. These two basic steps can also be done in one Step summarized what, for example, with the Lei Web production by screen printing using conductive polymer pastes is the case.

In the production of conductor tracks from pure metals, for example copper (Cu) or aluminum (Al), and Me valley alloys, two steps are required. First, the metal is applied to the entire surface of the substrate rial applied. Mechanical processes are involved in for example rolling metal foils, chemical or electrochemical deposition processes or evaporation processes drive, for example sputtering, PVD, CVD (PVD = Physical Vaper deposition; CVD = Chemical Vaper Deposition) turns. The structure is then carried out in a second step ration by means of mechanical methods, for example by Milling, or by a combination of photolithographi processes and etching processes. The latter two Procedures are often the cost determining factors PCB manufacturing. These expensive steps need for the structure for each individual substrate tion can be applied. In the known Ver driving are therefore cost reductions only by summarizing Solution of several substrates possible for one benefit, because here all  Substrates of use at the same time a process step run through.

After structuring the metallization, the Lei orbits on chemical or electrochemical processes reinforced or with additional functional layers, at for example made of nickel or gold.

The above-described metal conductor formation Substrates, i. H. Circuit carriers, has crucial Disadvantage. First of all, all substrates must be the appropriate ones go through the process steps described. This means ever but that the substrate materials for the processes mentioned must be suitable, or alternatively the processes on the Materials must be coordinated. Correspondingly inexpensive other materials, such as those for the manufacturer smart card or label inlets are only comparatively complex with pure metal alloys Manufacture sheets or alloys or layer structures bar. Furthermore, the high costs for the Lithogra fall structuring for each substrate or sub stratnutzen, so that the cost share of this process on finished substrate is very high.

For the production of conductor tracks in the production of Smart card or label inlets are often filled Polymer pastes used. However, it should be noted that that to produce very fine structures up to about 100 µm Lei distance between the tracks is usually unprinted suitable is. Rather, here is a structuring of Me tall layers on the substrate carrier by means of photolithography phie and subsequent etching process necessary. Here it can especially when creating conductor tracks on flexible Circuit boards that are only of small use or of role are editable to role due to process variation increased tolerances for the conductor geometry.

In addition to the above methods, direct  Generation of metal conductor tracks on the substrate by hot emboss. The ladder structure is created using ei punched out of a metal foil and the substrate at the same time by means of pressure and temperature transferred, or partially inserted into the substrate material presses. This process, as is the case with so-called "MIDs" (Molded-In terconnect devices) is mainly used visibly the usable substrate materials and he the smallest structure sizes that can be produced are severely restricted.

The object of the present invention is a Inexpensive method for producing a conductive To create structure on a substrate that also the Erzeu enables very fine, highly precise structures, and Devices used in such a method can be create.

This object is achieved by a method according to claim 1 and Devices according to claims 12, 13 and 15 solved.

The present invention provides a method of making a conductive structure on a substrate, in which to next a material on or in structures of a re-used reversible tool holder is applied or introduced, to the conductive structure on or in the reusable to produce their tool carrier. In the following it will be generated te conductive structure of the reusable tool transfer carrier to the substrate.

A first embodiment of a reusable Tool carrier that can be used in the above method is a support element and a primary metallization, the is formed on the carrier element and depending on the is structured to be generated conductive structure which can selectively deposit the conductive structure. On second embodiment of a reusable work witness carrier has a primary metallization and a cover layer that is formed on the primary metallization and off  depending on the conductive structure to be produced up to the original metallization. Finally around summarizes a third embodiment of a reusable ren tool carrier for creating a conductive structure Recesses depending on the conductivity to be generated gene structure are formed in the pasty or rivers material and can be brought into a solid state is feasible to thereby generate the conductive structure.

The present invention thus provides a method that is made up of two basic processes. The first reason process is the manufacture of a conductive structure, before preferably a structured metallization layer, under Use a reusable tool. The second The basic process is then the transfer of these generated conductive capable structure on a substrate, preferably a scarf executives.

In contrast to the usual manufacturers described above Structured circuits are invented According to the structuring process of the metallization represents the later trace, not directly on the sub strat, but in a separate step. So that's what happens Substrate not with the required structuring processes in touch. In contrast to conventional processes neither the metallization layer on the substrate applied and then structured, the Metalli layer in a structuring process on the sub strat, as is the case with the generation of Conductor tracks made of filled polymer pastes using screen printing or when hot stamping metal foils.

Rather, according to the invention, the conductive is generated structure on a reusable tool carrier, the same only after completion on the substrate is transmitted. This is possible according to the invention because it is fixed was made that peelable conductive structures like of the usable tool carriers. This  is possible, for example, if a metallization layer chemically or electrochemically on a primary metallization is divorced. It has been shown that this is removable speed occurs with a variety of materials, for example as a primary metallization, preferably stainless steel, Titanium, tungsten, vanadium, palladium, chrome or alloys the same can be used. The conductive structure can then produced, for example, from copper, aluminum or gold become. One has excellent peelability preferred embodiment when using a TiW layer as primary metallization and chemical deposition copper as a conductive structure on the same shows.

When transferring the generated conductive structure from the reusable tool holder on the substrate or an intermediate carrier must be sufficient for the conductive structure on the substrate or the intermediate carrier be taken care of. For this purpose an adhesive layer can be applied the substrate or the intermediate carrier can be provided. Al Alternatively, it is possible to at least use the conductive structure partially press into the substrate material.

After the conductive structure has been detached, it is there again usable tool carriers again for re-application gene or introduction of a material to produce a conductive structure available as long as the same is not is damaged by wear. So is the same a permanent structuring of the track layout Carrier not required. At the reusable work Witness carrier is therefore a so-called majority specialist tool.

The method of producing the conductive structures or conductor tracks on an external Carrier, d. H. the reusable tool holder, and that subsequent transmission procedures have decisive advantages parts compared to conventional methods for conductor tracks  on substrates. The tool carrier is for several pros reflows are reusable, according to the respective Wear. Through this reusability of the carrier who the costs and environmental impact of the compared to structuring process that is not required by conventional methods se, d. H. Lithography and etching processes, saved. Erfin According to the substrates come on which the conductive Structure should be applied with the structuring process not in contact, so that a reduced load of the substrates takes place. In addition, are fiction according to the structuring or the minimal structure that can be generated door widths and distances regardless of the substrate that the appropriate conductive structure are applied should.

Preferred embodiments of the present invention are referred to below with reference to the attached drawing nations explained in more detail.

Show it:

Fig. 1 shows schematically the steps of a preferred method for creating a conductive pattern on a substrate according to the present invention, and

Fig. 2 shows schematically the steps of a method for the manufacture of a preferred embodiment of a reusable tool carrier according to the invention.

1, a preferred embodiment of a method according to the invention for producing a conductor track metallization on a substrate is first explained in more detail with reference to FIG. 1. The inventive method ren can, for example, produce coil metallizations on ticking foils for labels or contactless chip cards before. After generating the Spulenmetalli sinations by the method according to the invention, the films can then still with appropriate components, for. B. a transponder IC, and then laminated who the.

As shown in Fig. 1 in a step S1, a reusable tool carrier 2 is first provided, which in the illustrated embodiment has a carrier element 4 and a primary metallization 6 formed on the carrier element 4 . The primary metallization 6 is structured depending on the conductive structure to be produced, so that the conductive structure can be selectively deposited thereon. A method of manufacturing such a reusable tool carrier as shown in FIG. 1 will be explained later with reference to FIG. 2. The carrier element 4 can be formed, for example, by a silicon wafer, a ceramic, a metal plate or a rigid or flexible carrier made of plastic. In the preferred exemplary embodiment of the present invention, the structured primary metallization 6 is formed from titanium-tungsten.

On the Urmetallisierung 6 Leiterbahnmetallisierung 8 is now generated by a selective metal deposition is carried out in a chemical or electrochemical process in the illustrated embodiment. At this point, it should be noted that the metallization of the reusable tool carrier referred to herein as the primary metallization has to be made in such a way that the metallizations can be deposited on it in a chemical or electrochemical process, which later the conductor track on the substrate carrier, ie the Conductor metallization, result. However, the adhesion of these metallizations to be deposited on the primary metallization must be sufficiently low to enable the conductor metallization to be removed later. Furthermore, the deposition of the metallization must be carried out selectively on the primary metallization, with a deposition on the carrier element 4 having to be prevented. In a preferred embodiment of the present invention, the interconnect metallization 8 is produced by chemically depositing a copper layer on the structured titanium-tungsten primary metallization.

The tool carrier 2 , on which the conductor metallization 8 is generated, is shown at 52 in FIG. 1. This Leiterbahnme tallisierung 8 is now transferred to the actual substrate 10 , which is shown at 53 in Fig. 1. For this purpose, in the illustrated embodiment on a lower surface of the substrate, ie the circuit carrier 10 , an adhesive middle layer 12 , preferably an adhesive layer, is provided. As indicated by the arrows 14 , 16 and 18 in Fig. 1, the surface of the tool carrier 2 on which the interconnect metallization 8 is formed and the surface of the substrate 10 on which the adhesive layer 12 is formed are now brought together, as in 54 in Fig. 1 shows ge. Subsequently, as indicated by the arrows 20 and 22 , the reusable tool holder 2 and the substrate 10 are separated, whereby the conductor track metallization 8 due to the detachability thereof from the primary metal coating 6 and due to the adhesive effect of the adhesive layer 12 is detached from the tool holder 2 and remains on the substrate 10 . Thus, after the completion of the process, the reusable tool carrier 2 is available for a new metal deposition, as shown at 55 in FIG. 1. On the other hand, as shown at 56 in FIG. 1, there is the substrate 10 provided with the interconnect metallization 8 .

In the illustrated embodiment, the reusable tool carrier can be used many times as long as the primary metallization 6 is not damaged. The substrate shown at 56 in FIG. 1 can then be processed further, for example by applying a transponder IC over the schematically illustrated conductor ends 8 ′ and 8 ″ of the schematically illustrated coil metallization 8 .

In the following, referring to FIG. 2, briefly refer to a process for producing the reusable tool carrier 2 shown in FIG. 1. First, the carrier element 4 is provided in a step S10. As indicated above, this can be a silicon wafer, a ceramic, a metal plate or a rigid or flexible carrier made of plastic. On this Trägerele element 4 then a Urme tallisierung 30 is applied over the entire surface in a step S12. The preferred exemplary embodiment of the present invention is titanium tungsten. Alternatively, however, other materials can be used, on which further conductive materials can be deposited electrochemically or after germination by chemical means, but which have a low adhesion to the primary metallization. For example, stainless steel, titanium, tungsten, vanadium, palladium, chromium or alloys thereof can be used as the primary metallization.

The application of the full-surface primary metallization 30 can be carried out in any conventional manner, for example the rolling on of metal foils, a chemical or electrochemical deposition or vapor deposition processes, such as, for example. B. Sput tern, PVD and CVD, are applied.

Subsequently, in a step S14, the original metallization 30 applied over the entire surface is structured using a photoresist 32 which is exposed via a mask 34 , as indicated schematically by the illustration of an incandescent lamp 36 . After exposure, a corresponding etching is carried out to complete the structuring, so that after the structuring step S14 the finished, reusable tool carrier 2 , which has a carrier element 4 on which the structured primary metallization 6 is formed, is present.

In addition to the structuring described above by means of photolithography, the primary metallization layer 30 can, for example, also by mechanical methods, such as. B. milling or laser evaporation, structured. In each case, the structure which remains when the plan view of the carrier element is viewed from above is a mirrored image of the conductor track to be produced later on the substrate carrier.

At this point, it should be noted that the procedure described with reference to FIG. 2 is merely an example for the manufacture of the reusable tool carrier 2 , alternatively other methods that are known from the prior art for applying a structured metallization are used for generation the originalization 6 can be used on the carrier element 4 .

In the method according to the invention described above with reference to FIG. 1, the interconnect metallization 8 was produced by means of selective deposition on a structured primary metallization 6 . Alternatively, it is possible to produce the conductor track metallization using a reusable tool carrier which has a full-surface primary metallization which has recesses up to the primary metalization due to a covering layer which is formed thereon and, depending on the conductive structure to be produced, is covered. In other words, a full-surface primary metallization is covered with a mask, or a structured covering layer is produced thereon. The part of the material of the primary metallization not belonging to the conductor path structure to be produced is covered by this cover layer, while the openings of this cover layer, which extend to the surface of the primary metallization, represent the corresponding mirror image of the later conductor path. In this case, the desired prevention of the deposition of the conductor metallization to be applied later in the areas in which no conductor structures are to be achieved is achieved by the mask above the primary metallization. The Leiterbahnme tallisierung then grows, starting from the surface of the primary metallization, only in the openings of the mask or cover layer. The cover layer can, for example, by applying a photoresist, e.g. B. by Aufschleu, and a subsequent photostructuring of the same are generated. In such a case, it is not necessary to provide a separate support element; rather, the carrier element can itself be formed by the primary metallization. The above-mentioned materials are again suitable as the primary metallization material, with, for example, stainless steel, which is used for galvanic deposition, being suitable if the external carrier is formed by the primary metallization itself. In the exemplary embodiment described above of a reusable tool carrier, a coating of a separately manufactured carrier with a primary metallization is no longer necessary.

Again, alternatively, the reusable tool holder ger be a one-piece element in which, depending on the recesses are to be formed for the conductive structure to be produced are in the pasty or liquid material can be brought and brought into a solid state in order to be there to generate through the conductive structure. The educated Recesses correspond to a mirror image, d. H. a negative, the conductive structure to be produced. Here, the production of the conductor track by the Ver pastes or dispersed liquids are used conditions that are conductive, at least in the solidified state. Examples of these are conductive polymer pastes call. For this purpose, the corresponding conductor track shape in the Tool holder incorporated, for example by mechani cal processes such. B. milling, chemical processes, such as e.g. B. etching, or electrochemical or other methods, such as e.g. B. lasering or eroding. It is brought into this form then introduced the paste or liquid, for example by printing, casting or dispensing. After the evaluation or solidification process becomes the conductor track in the over Transfer process transferred to the actual substrate. Also the prerequisite here is that the solidified conductor track can be detached from the tool carrier. This is preferable verse the surface of the tool carrier with a material hen on which the conductor track adheres poorly. This Ma material depends on the conductor paste or Lei used  rail fluid. For example, here Partly use Teflon (PTFE = polytetrafluoroethylene) after structuring on the reusable tool carrier is applied. Alternatively, the entire carrier or at least parts thereof are made of PTFE.

In the preferred exemplary embodiment of the method according to the invention described above with reference to FIG. 1, the surface of the substrate 10 to which the conductor track structure 8 was to be applied was provided with an adhesive layer 12 . As a result, after the substrate has been brought into extensive contact with the tool carrier, the conductor track is detached from the tool carrier and adheres to the substrate due to the adhesive force of the adhesive layer of the substrate and the low adhesive strength of the conductor track metallization on the primary metallization. This peeling can take place simultaneously over the entire area or step by step by rolling or obliquely pulling the substrate from the tool holder. Alternatively, the adhesive layer can also be provided on the conductor track metallization still located on the tool carrier. However, the adhesive layer is preferably applied to the entire surface of the substrate. Alternatively, it is possible for the substrate to be selectively provided with the adhesive layer only on partial surfaces, for example the areas on which the conductor tracks come to lie. In any case, however, the adhesion between the substrate and the respective free surfaces on the tool carrier, on which there is no interconnect metallization, must be as low as possible so that only the interconnect metallizations are detached.

The required adhesive effect between the interconnect metallisie tion and destination substrate to which it is applied can be generated in other ways. At for example, the conductor track when contacting substrate and external carrier under pressure and possibly simultaneously Exposure to temperature at least partially in the substrate material are pressed in, so that the Haf  between the substrate and the conductor track metallization is fathered.

Although according to the above description, the trace metal in each case directly from the tool carrier onto the loading mood substrate has been applied, it is possible to To use intermediate carrier, so that is contrary to the above described single transfer process a double transfer process results. In any case, it is necessary that the Haf between primary metallization and interconnect metallization is less than that between interconnect metallization and substrate on which the conductor track metallization is applied bring is present.

Claims (16)

1. A method for producing a conductive structure ( 8 ) on a substrate ( 10 ) with the following steps:
Application or introduction of a material on or in structures ( 6 ) of a reusable tool carrier ( 2 ) for producing the conductive structure ( 8 ) on or in the reusable tool carrier ( 2 ) and
Transfer the generated conductive structure ( 8 ) from the reusable tool carrier ( 2 ) to the sub strat ( 10 ). 2. The method according to claim 1, wherein the reusable tool carrier ( 2 ) has a primary metallization ( 6 ) on which a structured metallization as the conductive structure ( 8 ) is deposited. 3. The method according to claim 2, wherein the primary metallization ( 6 ) is structured depending on the conductive structure to be produced ( 8 ), and in which the metallization is deposited selectively on the primary metallization ( 6 ). 4. The method of claim 2, wherein the reusable Tool carrier a cover layer on the primary metal tion, depending on the one to be generated conductive structure recesses up to the primary metal are formed. 5. The method according to any one of claims 2-4, wherein the original metallization ( 6 ) consists of a material selected from the group consisting of stainless steel, titanium, tungsten, vanadium, palladium, chromium or alloys thereof. 6. The method according to any one of claims 1-5, wherein the  conductive structure made of copper, aluminum or gold is forming. 7. The method of claim 1, wherein the conductive structure generated in the reusable tool carrier is made by using a pasty or liquid material in recesses of the reusable tool holder introduced and brought into a solid state. 8. The method according to claim 7, wherein at least the upper area of the recesses of the reusable tool are coated with Teflon. 9. The method according to any one of claims 1-7, wherein the conductive structure ( 8 ) is transferred to an intermediate carrier before transfer to the substrate ( 10 ). 10. The method according to any one of claims 1-9, wherein the sub strate ( 10 ) or the intermediate carrier are provided with an adhesive ( 12 ) before the step of transferring. 11. The method according to any one of claims 1-6, wherein the conductive structure when transferred to the substrate in the substrate is pressed. 12. Reusable tool carrier ( 2 ) for producing a conductive structure, with the following features:
a carrier element ( 4 ) and
a primary metallization ( 6 ) which is formed on the carrier element ( 4 ) and which is structured as a function of the conductive structure ( 8 ) to be produced, on which the conductive structure ( 8 ) can be selectively deposited. 13. Reusable tool carrier for creating a conductive structure, with the following features:
a primary metallization and
a cover layer which is formed on the primary metallization and which, depending on the conductive structure to be produced, has recesses up to the primary metallization. 14. Reusable tool carrier according to claim 12 or 13, wherein the primary metallization ( 6 ) consists of a material selected from the group consisting of stainless steel, titanium, tungsten, vanadium, palladium, chromium or alloys thereof. 15. Reusable tool carrier to create a conductive structure, the recesses that depend on of the conductive structure to be produced, has in the pasty or liquid material can be introduced and brought into a solid state, to thereby create the conductive structure. 16. Reusable tool carrier according to claim 15, at which at least the surfaces of the recesses with Tef lon are coated.