DE102004032533A1 - Production of multiple layer ceramic composite used in electronics industry comprises forming metallic layer structures on film-like intermediate support, positioning support between films and forming composite - Google Patents

Abstract

The production of a multiple layer ceramic composite comprises forming metallic layer structures on a film-like intermediate support (2) made from a material which is fired, vaporized and/or sublimed in a region between the baking temperature of the binder materials and the sintering temperature of the ceramic foils, positioning the intermediate support between at least two films or plates made from non-fired ceramic and forming a composite under the influence of pressure and temperature. A baking and sintering process is carried out, in which the intermediate support is fired, vaporized and/or sublimed and removed from the composite. A force exerting a uniaxial pressure is applied to the composite temporarily during the baking and sintering process.

Description

The The invention relates to a method for producing a multilayered Ceramic composite with internal metallic structures according to the features of the first claim.

To the prior art are metallic layer structures, the mainly as tracks for Electricity can be used directly on unfired ceramic or glass-ceramic foils with the aid of at least partially of metal particles applied to existing pastes or slips. This happens mainly through Screen printing, sometimes in combination with photolithographic Method. The provided with the metallic structures ceramic films are then submerged Influence of pressure and temperature connected. In the following burnout and sintering process creates a ceramic composite with internal Channels and possibly with active structures such as resistors, capacitances and the like. To during the manufacturing process the ceramic composite to reduce its lateral shrinkage or to prevent on the outside of the association of higher - order Applied ceramic films and / or during the firing process uniaxial pressure on the composite to be produced.

disadvantage This known method is that the application of the metal-containing layer structures on the unfired ceramic or glass ceramic foils only with process can be done, which does not chemically the unfired ceramic films strain. As a result, the geometric and electrical Properties of the generated metallic layer structures in comparison significantly limited to layer structures on other substrates and the general benefits ceramic multilayer systems can consequently only partially used.

to Minimization of these chemical stresses are known methods where for the application of the layer structures intermediate carrier can be used. In the structured a first step on the intermediate carrier Layers are subsequently mechanically transferred to the unfired ceramic films.

at These methods are the layer structures as well as the unfired ones Ceramic films exposed to correspondingly strong mechanical loads.

From the DE 100 39 296.2 a method for the production of ceramic components is known, in which an intermediate carrier is positioned with the applied layer structures between the ceramic films and decomposed during the subsequent Ausbrenn- and sintering process of the intermediate carrier almost residue-free. The starting mixture for the coating is likewise a paste or a slip in this process. During the subsequent burn-out and sintering process, sintering of the ceramic films and the applied layer structures takes place, which is associated with a shrinkage of the ceramic films and the layer structures.

The by means of all these known methods applied active structures from at least partially made of metal particles pastes or slip with regard to their resolution, layer thickness, Contour, shape and electrical parameters disadvantages. You own a low dimensional stability and due to the sintering shrinkage their final shape is very tolerant. In addition, they have a low conductivity and a poor noise performance.

To overcome These disadvantages are the applied active structures of a solid metallic or full metallic material are made. Problematic in the production of these fully metallic structures is, however, that necessary for their application chemical or electrochemical processes and / or thin-film processes, such as vapor deposition and sputtering, only with great effort or under heavy use of the unsintered ceramic films can be performed.

task Therefore, the present invention is a process for production to provide a multilayer ceramic composite, with the the chemical and mechanical loading of the unfired ceramic films and the applied active structures minimized and simultaneously the electrical and the shaping properties of the active structures be improved.

According to the invention succeeds the solution this task with the features of the first claim.

advantageous Embodiments of the method according to the invention are in the dependent claims specified.

The The invention is explained in more detail below with reference to drawings. The associated Drawings show:

1 Generation of metallic structures on an intermediate carrier

2 Production of a composite under the influence of pressure and temperature

3 Burn-out and sintering process with outgassing of the intermediate carrier and bonding the ceramic films under uniaxial pressure

4 Sintered ceramic composite with internal metallic structures

In the first step of the process according to the invention ( 1 ) is a non-pasty or slip-shaped metallic structure ( 1 ) on a preferably foil-shaped intermediate carrier ( 2 ) applied. This can be done by vapor deposition, sputtering, pressing, gluing and / or chemical or electrochemical processes, if necessary in combination with lithographic processes. A particular advantage of the proposed method is that the intermediate carrier used can be selected so that structuring processes can be used which are not or only to a limited extent possible on unsintered ceramic or glass ceramic foil. The material from which the film-shaped intermediate carrier is designed must burn, vaporize and / or sublime at temperatures which are in the range between the burnout temperature of the binder materials and the sintering temperature of the ceramic films. The intermediate carrier may also contain other organic or inorganic layers or structures which serve as adhesion promoters or to increase the chemical resistance.

The foil-shaped intermediate carrier ( 2 ) with the generated structures ( 1 ) is then between at least two unfired ceramic sheets or plates ( 3 ) ( 2 ). Under the influence of pressure and temperature, intermediate carriers and ceramic films are connected to each other. On the outer sides of the composite, special unfired ceramic films (release tape) ( 6 ), which have a higher sintering temperature and serve the purpose of limiting the lateral (xy shrinkage) and preventing the adhesion of the composite to the pressing tools. They can be removed after the sintering process.

In the next step ( 3 ) takes place a burn-out and sintering process, wherein at least temporarily a preferably uniaxial pressure is exerted on the composite, which completely or partially prevents the formation of voids in the composite and supports a close together sintering of the ceramic or glass ceramic sheets or plates. The result is a mechanically stable ceramic composite, without the need for additional adhesion promoters (eg low-melting glasses, etc.) ( 4 ). During the firing process, a temperature range occurs in which the initially unfired ceramic films become partially porous by burning out of the binder materials contained. Due to the material properties of the intermediate carrier, at the same time or later, it also begins to burn, evaporate and / or sublime in this temperature range and thus escape from the composite via the resulting pores. After reaching the sintering temperature of the ceramic films, the pores close and the resulting ceramic composite contains the desired internal metallic structures.

at the production process according to the invention becomes the so-called pressure-assisted 0-shrinkage process, during that the Ausbrenn- and sintering process at least temporarily a uniaxial Pressure exerted on the substrate is applied. This can reduce the sintering shrinkage of the ceramic materials be controlled so that the production of multilayer ceramic composites internal active structures made of fully metallic materials, unlike pastes or slips during the sintering process or shrink only minimally (<10%), in combination with a while of the sintering process dissolving support material possible becomes.

Of the Burn-out and sintering process can be achieved by the use of oxidizing, reducing or inert gases or by working under vacuum to be controlled.

By The method described makes it possible to have a multilayer ceramic composite with internal metallic structures in high precision and structural resolution manufacture. It can the metallic structures made on the foil-shaped intermediate carrier be without the unfired ceramic films chemically or mechanically be claimed. The solution the generated structures from the subcarrier takes place during the Burning process within the composite, which fixes the structures and by the slow removal (outgassing) of the intermediate carrier material are hardly exposed to mechanical stress.

The inventive method is an embodiment explained in more detail.

On an intermediate carrier made of polyimide film, a conductive starting layer required for the electrodeposition is applied by sputtering on silver. This is then provided with a resist, which is structured photolithographically. Subsequently, the silver layer is galvanically reinforced in the openings of the resist. Then resist and uncovered parts of the starting layer are removed, so that only the galvanically reinforced structures remain. Subsequently, the intermediate carrier between several layers of unfired ceramic films, in the special case LTCC (Low Temperature Cofired Ceramics) positioned. At the top and bottom of each still designated as a release tape unfired ceramic film (eg alumina ceramic) is applied, on the one hand reduces the lateral sintering shrinkage and on the other hand prevents subsequent adhesion of the composite pressure sintering or the pressure distribution plates. By compressing the stacked films, these are bonded together at temperatures above 30 ° C. The LTCC material itself may still contain metallic and / or non-metallic structures as well as feedthroughs.

Subsequently, will subjected the substrate to a sintering process, in accordance with the invention a uniaxial Force on that substrate is exercised becomes. From a certain temperature (about 250 ° C) is a burnout of the organic Binder of the LTCC material. At the same time or later begins the subcarrier to burn and / or sublimate. In this case, the resulting, mainly gaseous waste products through the now porous Leak LTCC material. After the intermediate carrier largely from the substrate escaped and the burnout of the binder materials is completed, remain the former on the intermediate carrier structures in the LTCC composite and this is under temperatures between 800 ° C and sintered at 1000 ° C.

At the End of the process is a multi-layer ceramic composite with inside metallic structures in front of the on conventional Improved manner produced ceramic composites electrical and shaping properties (resolution, dimensional stability, contour, Layer thickness).

1

metallic structures

2

subcarrier

3

unfired "green" ceramic films

4

unfired Ceramic films (release tape) with

higher sintering temperature

5

versinterter ceramic Composition

Claims (9)

A method for producing a multilayer ceramic composite with internal metallic structures of unfired ceramic films, characterized in that • on a preferably foil-shaped intermediate carrier of a material which burns in a range between the burn-off of the binder materials and the sintering temperature of the ceramic films evaporated and / or sublimated, metallic Layered structures are produced, • the intermediate carrier is positioned between at least two sheets or plates of unfired ceramic and is produced under the influence of pressure and temperature, a composite, • a burn-out and sintering process takes place, in which the intermediate carrier burns, evaporates and / or sublimated and escapes from the composite, wherein at least temporarily acts a force on the composite during this burn-out and sintering process, which preferably produces a uniaxial pressure. Method according to claim 1, characterized in that the bonding of the ceramic foils to the one positioned therebetween subcarrier under pressure and temperature and the burnout and sintering process with at least temporarily uniaxial pressure applied to the composite, at the same time respectively. Method according to one of claims 1 or 2, characterized that the metallic structures on the subcarrier through chemical or electrochemical processes and / or by thin-film techniques, partially in combination with lithographic processes become. Method according to one of claims 1 to 3, characterized that on the subcarrier applied further organic or inorganic layers or structures become. Method according to one of Claims 1 to 4, characterized that on the outsides of the Composite unfired ceramic films or pastes are applied, their sintering temperatures over the process temperatures are. Method according to one of claims 1 to 5, characterized that the ceramic films used mainly in one direction (z-direction) while of the sintering process shrink. Method according to one of Claims 1 to 6, characterized that while the burn-out and sintering oxidizing, reducing or inert gases or vacuum can be used. Method according to one of claims 1 to 7, characterized that the unfired ceramic films with metallic or non-metallic layer structures and bushings are provided. Method according to one of claims 1 to 8, characterized that several intermediate carriers and ceramic sheets are stacked.