DE2531199A1 - CONDUCTIVE METALLIC COMPOSITION FOR COATING CERAMIC SUBSTRATES AND PROCESS FOR MANUFACTURING THE SOUL - Google Patents

Description

heb-aa

Applicant: International Business Machines

Corporation, Armonk, N.Y. 10504

Official file number: New registration file number of the applicant ι FI 973 075

Conductive metallic material composition to be coated of ceramic substrates and methods of making the same

The invention relates to an electrically conductive metallic material composition and a method for its production, Ceramic materials are widely used today in electrical engineering in the manufacture of electrical devices. A such application area is the production of multilayer ceramic modules (hereinafter referred to as MLC), which in the generally from a number of layers of a ceramic, insulating material, internal electrically conductive Metallizations and corresponding metallizations exist on the surface. Such multilayer structures and similar materials are described, for example, in "Laminated Ceramics" by Schwartz et al., Ceramic Age, June 1967, rarely 40 to 44; "Ceramics for Packaging", Wilcox, Solid State Technology, Parts 1 and 2, January, February 1971, starting on pages 40 and 55; "A Fabrication Technique for Multi-Layer Ceramic Modules," Kaiser and Others, Solid State Technology, May 1972 beginning on page 35; "Metal-Ceramic Constraints for Multi-Layer Electronic Packages ",

50 9887/1038 originally inspected

Chance et al, in Proceedings of the IEEE, 59, pp. 1455 ff, (1971).

Components such as multilayer ceramic modules or MLC are often used when there is high temperature, high humidity and / or other harmful environmental influences are present. The metallization used under these conditions must be Operation highly resistant to such environmental influences to avoid failure of the device and to ensure that the original electrical Properties of the device obtained for a considerable period of time with no significant or noticeable deviations stay.

While conducting metallization Stoffzusamraensetzungen generally known _r yet few of these compositions are currently available, which simultaneously have both a high resistance to high temperatures and high humidity and / or other harmful environmental world influences, while with ceramic dielectric materials as used in electronic Components are used, are well tolerated and can also be produced at affordable costs. For example, US Pat. No. 3,497,384 shows a platinum-ruthenium alloy with a content of 60 to 100% platinum. US Pat. No. 3,679,439 discloses a frit made of a noble metal and glass with a lead content of 1 up to 25% and US Pat. No. 3,708,313 indirectly discloses the use of metallizing compositions of matter made from platinum and ruthenium.

The compositions of matter mentioned in US Pat. No. 3,497,384 for metallizations are expensive and crack when fired in a reducing atmosphere.

The frits disclosed in US Pat. No. 3,679,439 are made with ceramic, dielectric,

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do not see materials as compatible, as they use materials contain a low melting point and can evaporate and condense at the high firing temperatures or sintering temperatures. In addition, very high shrinkage can occur with these materials at the high firing or sintering temperatures.

The compositions of matter disclosed in U.S. Patent 3,708,313 either have the disadvantages outlined above or are exceptionally expensive

Other compositions of matter or conductive elements of the most varied Art are described in the following US patents:

U.S. Patent 2,793,273

U.S. Patent 3,329,526

U.S. Patent 3,407,081

U.S. Patent 3,620,840 and U.S. Patent 3,679,606.

The object of the invention is therefore, to provide a novel _f electrically conductive composition for the coating and the metallization of multilayer ceramic substrates which do not have the above disadvantages and have good compatibility with highly refractory, sintered at high temperatures ceramic materials. The present invention provides an electrically conductive metallization material composition which is particularly suitable for the production of metallizations on and / or in a ceramic substrate which is used for electrical components. The electrically conductive metallization material composition consists essentially of ruthenium with molybdenum and / or tungsten *

In a further embodiment of the invention, the electrically conductive material composition contains for metallizations also a ceramic frit. The ceramic frit serves to improve the adhesion between the metallization and the

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increase ceramic substrate. The presence of a small amount of glass frit gives more uniform adhesion.

Particularly favorable results are achieved if you work in an electrical component carries out the metallization on the surface with a high proportion of ruthenium, while the internal metallizations have a corresponding content of molybdenum and / or tungsten.

This electrically conductive composition of matter for metallization can be applied to both unfired and fired ceramic substrates. In the first case will the composition of matter is usually applied as a paste and sintered together with the ceramic substrate.

Electrically conductive compositions of matter for metallizations according to the present invention are particularly suitable for the application and production of metallizations inside and outside of multilayer ceramic bodies,

The invention is now based on exemplary embodiments described in more detail in connection with the accompanying drawings. The features of the invention to be protected can be found in detail in the attached claims.

In Figs, 1 _f 2, and 3 are sectional views of multilayered ceramic structures using a metallization according to the invention are shown schematically.

To simplify the description, the following terms should be used in the following «

The expression "electrically conductive material composition for metallizations" generally refers to any material

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composition, the ruthenium, Molydbän and / or tungsten according to of the present invention. In some embodiments a ceramic material is also used, and when the description refers to such an embodiment, the The term "metal-ceramic material composition" is used.

The term "metallization" refers to the from a conductive composition of matter for metallization electrically conductive tracks, regardless of whether they are outside or inside a ceramic substrate. Unless otherwise stated, this term refers to a conductive path present in the finished component i.e. when using a conductive metallic composition in the case of an unfired ceramic substrate to the state after sintering «

The term "metallic constituents" relates in particular to ruthenium, molybdenum and / or tungsten which are present in the conductive Compositions of substances for metallizations according to the present invention Invention are included

The electroconductive metallization composition of matter according to the present invention is generally used for manufacture used by metallic conductors on ceramic materials and can not only be used for the formation of internal or external cable runs, but also for connections in between, i.e. e.g. for seals between insert the ceramic material and metal *

In particular, the electrically conductive, metallic composition of matter according to the present invention is suitable for Application in the manufacture of complex components and assemblies for data processing technology, especially for MLC (Multi-Layer-Ceramlcs), which are commonly used in the the aforementioned literature references are described. Accordingly, the following description essentially refers to

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the use of the electrically conductive compositions of matter according to the invention for use in MLC ¹ p.

First of all, the graded MLCs to be discussed later will not be discussed. The simplest electrically conductive Composition of matter for metallizations according to the invention consists of ruthenium and at least one of the two metals molybdenum or tungsten, i.e. ruthenium-molybdenum, ruthenium-tungsten or ruthenium-molybdenum-tungsten.

In such a system, the ruthenium is preferably represented with 5 percent by weight to about 40 percent by weight of the metallic constituents. However, if desired, smaller proportions of ruthenium can also be used. Thereby, since both the cost is reduced and the electrical resistance _f which is both desired, but the concomitant decrease in resistance speaks of the material to high temperatures, high humidity and harmful environmental influences clearly against the use of Rutheniumanteilen substantially below 5 weight percent of metallic constituents That is, approximately on the order of 1% by weight. It is also possible to use a proportion of ruthenium greater than 40% by weight of the metallic constituents. However, this increases the cost and increases the electrical resistance for most of these systems.

If the proportion of ruthenium approaches that of pure ruthenium, a low electrical resistance is found. Although such a system is useful for some areas of application, the use of such is out of the question Due to the high cost of the system, a high level of shrinkage in the metallization can also be observed when ruthenium is applied Interfaces with molybdenum and / or tungsten meets. However, such a ruthenium metallization can be used in combination Use graded metallization to form excellent MLCs; that is, metallization goes from one to the other

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The ruthenium metallization on the surface is made of pure or almost pure ruthenium in steps into an internal one Metallization from molybdenum and / or tungsten over.

If you weigh the costs, the electrical resistance, the resilience against harmful environmental influences and the compatibility with commonly used MLC substrates against each other particularly favorable results are obtained with 8 to 25 weight percent ruthenium based on the content of metallic components, with an optimal balance of the properties at about 10 percent by weight ruthenium on the basis of the metallic components.

The remaining metallic components of the electrically conductive material composition for metallizations consists of 95 to about 60% molybdenum and / or tungsten.

Molybdenum and tungsten can either be used alone or in mixtures with all of the mixing ratios in between can be used because they act in the same way in the metallization and form a complete solid solution with one another.

Electrically conductive material compositions for metallizations that only consist of ruthenium _f molybdenum and / or tungsten, i.e. without a ceramic base, are particularly important in the production of metallic cable runs, such as cables on surfaces, internal cables, internal plated connections and the like ( electrically conductive tracks between the individual layers in an MLC) useful when the adhesion to the substrate is less important.

The electrically conductive material composition for metallizations according to the invention can also be a ceramic Material included. The same mixing ratios are used in such systems used as mentioned earlier.

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The only change is the presence of a ceramic component,

The main task of the ceramic component is to ensure the adhesion between the metallization and that of the metallization to improve load-bearing ceramic substrate. A composition of matter made up of conductive metal and ceramic material according to the invention is used in particular when the adhesiveness is of paramount importance and a certain increase in electrical resistance due to the ceramic component is permissible i.e. when soldering to a terminal or the like, for example.

Since ceramic materials are actually insulators, care should be taken not to use too high a proportion of ceramic Material are present in the composition of matter consisting of metal and ceramic material.

If you use too much ceramic material, the metallization made from it is suitable for use in one MLC actually non-conductive, D, h, but that one does not exceed 75 percent by volume of the total volume of the metallic-ceramic Compositions of substances should use ceramic material.

On the other hand, if the ratio of ceramic material to metal is reduced, the adhesive effect and the Resistance of the metallization produced therefrom, the lowest resistance value being reached when the ceramic The proportion of metallization is approaching 0 percent by volume.

If one weighs the effects just described of increasing adhesiveness and decreasing resistance against each other starting, one will preferably use the ceramic material with about 5 to about 50 percent by volume of all ceramic and metallic

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Choose components, whereby one should only move to higher proportions of ceramic material if the adhesion is of particularly critical importance. An optimal balance between adhesion and resistance is obtained for most Tasks occurring in MLCs with a ratio of ceramic material to metallic components of 30 percent by volume at 70 percent by volume.

A person skilled in the art will readily understand that in the manufacture of an MLC the ceramic or glass-ceramic system of the substrate is generally selected first for the required electrical properties exhibited by the device target. Then the required metallurgy is selected that should be compatible with the ceramic substrate.

With these assumptions in mind, one will generally preferably the same ceramic material in the electrically conductive material composition for the metallization as in the ceramic substrate to ensure full compatibility. For example, if you use an alumina substrate, then one would call it a ceramic material, which is the electrically conductive composition of matter for Metallization is added, also select alumina.

If desired, the two ceramic materials can also be different if the following boundary conditions be respected"

a) that in the electrically conductive composition of matter Ceramic material contained in metallizations should have a material shrinkage and have a coefficient of thermal expansion sufficient to that of the ceramic substrate comes close so that the resulting metallization does not become detached from the substrate and

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b) the two ceramic materials should be mutually exclusive do not trigger any undesirable and harmful chemical reaction,

Examples of preferred ceramic materials that can be used both for the formation of a ceramic substrate and in that of conductive Metal and ceramic material composition can be used according to the invention are, for example, alumina, mullite, beryllium, titanium, fosterite, zircon, Steatite and the like. All of these ceramic materials are dielectric ceramics as they are commonly used as is the case with all ceramic materials used in connection with the invention.

In a further embodiment of the invention, a small Part of the ceramic material can also be replaced by a glass, which results in a more uniform adhesion.

Such glass should be liquid in particular at a temperature below the sintering temperature of the ceramic substrate temperature, so that it begins to flow and to be sintered pores and gaps in the electrically conductive, for the metallization used composition fills _f should in no way with other Components react in a harmful way and do not change adversely under sintering conditions.

Since the glass is intended in particular to improve the adhesion for the ceramic material, it is generally only used with a small amount Proportions used, with the best results with proportions of about 5 volume percent to about 20 volume percent or less glass, based on the volume of ceramic material and glass, can be achieved.

If the ceramic substrate does not contain glass, for example consists of pure clay, then one will in general

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for the electrically conductive composition of matter preferably do not use glass and this may also be undesirable in connection with relatively porous ceramic substrates, since the glass in the electrically conductive material composition to be sintered, preferably during the sintering process, penetrate into these pores can.

Although there are no particular restrictions on the glass used, it is preferable to use glasses such as e.g., aluminosilicate glasses such as those described in the above Essay by Kaiser and others are described. These are high-temperature glasses that are used in a Temperature below the sintering temperature of the ceramic material soften. Such glasses consist essentially of alumina and silica or silicon dioxide with minor amounts Constituents of modifying oxides, such as, for example, alkaline earth metal oxides and the same.

If the electrically conductive substance composition is determined according to Invention is applied to an unfired or unsintered, i.e. green ceramic substrate, and the two are intended to be sintered together then this material is preferably used as a paste in the screen printing process or with a metallic Mask or stencil applied using known binders, such as those in the US patent 3,374,110.

The binder used for the paste generally contains a binder resin and a solvent for the binder resin. The binder causes the metallic constituents of the conductive material composition to adhere to or in the substrate in the desired position when the solvent is driven off. Such binders are for example natural rubbers, synthetic resins and cellulose-based manufactured resinous materials and the like. The solvent gives the paste the desired viscosity. Included the solvent is selected in such a way that it is the

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Dissolves binder «Commonly used solvents are the higher-boiling paraffins, cycloparaffins and aromatic hydrocarbons or mixtures thereof, or one or more of the mono- and di-alkyl ethers or diethylglycol or their derivatives such as diethylene glycol monobutyl ether acetate. the Components of the binding agent of the paste are preferably mixed with one another beforehand before the solid components added · The binders are thermoplastic.

The paste is usually made by mixing the solid components, i.e. the metallic components, with the Ceramic material to be added on request and the glass to be used on request mixed with the binding agent of the paste. The order of this mixing is not important and, if desired, the binder for make the paste and then mix it with the desired solid ingredients.

The metallic components and the optionally added ceramic material and glass are generally in particulate form mixed with one another, into which they have either been brought or classified beforehand «The metallic components are mostly in the form of a metal powder or metal oxide powder (the metal oxide becomes during sintering reduced to metal when working in a reducing atmosphere; in the present application, the expression "Metal powder" in the following includes both cases), the ceramic The material and the glass are in the form of a frit. The particle size of the metal powder, the ceramic material and the glass frit is for monitoring shrinkage and for Constant properties of the paste are important and are generally of the order of 0.5 to about 4 micrometers. Smaller or larger average particle sizes can also be used, but a gradual decrease is seen stuck to the desired results when working outside this area. That is, if, for example,

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cozy little particles are used, then you get one On the other hand, excessively large shrinkage and the load on the binding agent, the paste with metal, is reduced ! large particles, so the particles can settle. These factors are known to the person skilled in the art and will be taken into account by him.

Since the binder is only temporarily present and during the drying and the heating of the Ceramic substrate is removed, the proportion of solid constituents to the binder is selected so that the Paste for a surface and / or side metallization and a good filling of the through holes in the MLC can be easily applied.

If only metallization is required on the outside surface or inside on the sides, then one generally will the proportions of solid constituents known from the prior art, as for example in the US patent 3 374 110 are described. If a complete filling of the through holes is required, one achieves excellent results with solids content of about 80 to 90 percent by weight and this percentage is generally used in the present invention.

The limit values given above are not absolute and you can also use higher and lower proportions of solid components, as long as the following errors are avoided. The proportion of solid components should not be so low that that shrinkage occurs with the formation of pits in the through holes during sintering (which leads to the formation of internal voids in the MLC and poor electrical conductivity) or that the metal content is so low that it results in unacceptable conduction ratios. The proportion of solid components should not be so high that for applying the paste with screen printing or with

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blonen not enough binder is present.

Of course, it is immediately obvious to the person skilled in the art that in some cases a certain shrinkage, a reduction in conductivity and some difficulty in applying the paste can be allowed and thus it is impossible to absolute Specify limit values for the content of solid components.

The solvent to binder ratio is used only in accordance with known procedures and is in no way particular critical. Viscosities of around 2000 or 40,000 cps are normal «

The electrically conductive material composition for metallization according to the invention is generally applied to an unfired or green ceramic substrate then applied when the ceramic substrate is punched out and with alignment holes is provided and after the through holes are made.

Although one screen printing process is successful for applying paste, the conductive fabric composition is usually created using a metal masking stencil introduced into the through holes.

In general, the screen printing process of metal mask stencils for green, unfired ceramic substrates is used at the same time, around the ceramic, which is used for metallization To apply the composition of matter, but these two, Methods that are intrinsically independent of one another can also be carried out separately in any order.

After the paste has been applied, the substrate is subjected to the usual procedures, namely;

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a) a drying process at approximately 60 ^° C. to drive off the solvent in the electrically conductive material composition;

b) Stacking of the individual unfired ceramic platelets, each with its own special metallization wear;

c) lamination of the stack of green, unfired flakes at elevated temperature and pressure,

d) sizing and removing excess ceramic material at the location of the alignment holes and

e) Firing or sintering the laminate, whereby one monolithic MLC with metallizations serving the connection is given »

During sintering, a cycle of heating, firing and cooling is run through. The period j during which the temperature of the conductive material composition located on the substrate is gradually increased up to the sintering temperature is called the heating-up period. During this first part of the heating-up period, the last traces of the solvent _r, if present, are evaporated. If the temperature is increased further, the binder decomposes and is removed from the conductive material composition as gaseous combustion products.

After the heating period, sintering is carried out at an elevated temperature, i.e. the ceramic body and the Conductive compositions of matter for metallization are sintered and compacted, thereby finalizing the device Get shape with their metallization. The sintering or firing is generally carried out in a reducing atmosphere, whereby oxidation of the metallic components is prevented.

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The multilayer ceramic body is then cooled and subjected to various post-processing steps, for example Electrolessly metallized with nickel, palladium or the like to provide a connection for the various To create lines to the metallization, further components are soldered and the whole thing is cleaned and checked.

As already indicated, all essential procedural steps are in the production of MLC are known and are sufficiently described in various literature references and patents. Having thus generally described the invention, some special examples are given to illustrate the invention,

Example I.

The following ingredients were placed in a three roll grinder mixed together to give a conductive composition of matter for metallizations, which consisted of 86 percent by weight of solid components and 14 percent by weight of binder.

Solid components

(Percent by weight) binder

Wetting RU Mo solvent binder medium

10 90 75 20 5

Ru is ruthenium metal powder with an average

Particle size of about 3.0 yam,
Mo is molybdenum metal powder of about 2.0 µm average particle size,

The solvent was butyl carbitol acetate; the binder was ethyl cellulose;
the wetting agent was Sarkosyl-0 (oleyl sarcosine); and the viscosity of the binder was 3000 cp.

Ten identical, unfired ceramic flakes were produced

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provides, as for example in the above-mentioned article is described by Kaiser and others. Before applying the metallization, each of the ceramic flakes was drilled with alignment holes and provide the required through holes.

The conductive composition of matter was then passed through a metal mask Applied as a template for filling the through holes in each ceramic flake and four of the ceramic Leaflets were screen printed to a thickness of about 0.0254 mm and a width of 0.178 mm for the production of the various Metallization printed.

This conductive material deposited in this way was ^{dried at 60 °} C. for 30 min.

The ten ceramic flakes were stacked, aligned, and laminated at 182 kg / cm and 40 ° C. and up cut to the required size so that the areas with the alignment holes are omitted.

This unfired structure is then sintered according to the following plan: an essentially uniform temperature rise over 3 hours from room temperature to about 350 ^° C. in a flowing, reducing gas, in this case hydrogen, for complete removal of the binder,

An essentially uniform temperature rise from 350 ^° C. to 700 ^° C. over about 3 hours in a wet hydrogen stream (average dew point at 45 ^° C.), followed by a uniform temperature increase up to about 1560 ^° C. over a period of 5 1/2 to 6 hours under the same conditions to remove the binder.

Then the temperature is for about 3 hours to about 1560 ⁰ C in a wet hydrogen atmosphere of about

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kept the same dew point.

The fired MLC is then cooled to room temperature, whereby first the cooling under a wet hydrogen atmosphere similar to the firing atmosphere is carried out very slowly in order to prevent extreme temperature differences arise, for example around 200 ° / h, followed by natural cooling, whereupon the furnace with hydrogen is flushed through.

Wet hydrogen is used in sufficient quantities to to decompose the existing organic binder and to oxidize any carbon residues that may be present.

The metallization was then examined and found to be firmly adhered. The substrate did not have thrown and no cracks in the substrate or in the metallization were found. When considering the following is described, it was found that the metallization is highly resistant to high temperatures, high humidity and harmful environmental influences,

Test method for resistance to high temperatures and high humidity

A sample produced according to the method described above was ^{exposed to a temperature of 85 °} C. and a relative humidity of 81%. After 1000 hours under these conditions, the electrical resistance of the metallization formed in this way had increased by less than 1% and the external metallization was clean and electrically conductive.

Another sample was then prepared in exactly the same way, except that the ruthenium was replaced with molybdenum, using the same test procedure. After 1000 hours at 85 ^° C. and a relative humidity

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from 81% the electrical resistance had increased by 18.1% and the exposed surface of the metallization was dark and had insulating properties, allowing local cleaning was necessary in order to be able to measure the electrical resistance.

A monolithic, multilayer ceramic module made from ten ceramic layers according to this example, is shown schematically in sectional view in FIG. The module | is denoted by the reference numeral 10, each of the ceramic Layers, although no longer separated from one another since the MLC are monolithic, are denoted by the reference numeral 11 designated. The line runs lying on the surface are denoted by 12, the inner lines by 13 and the metallizations filling the holes with 14,

A metallization according to Example 1 is particularly suitable for through-metallizing bores, since the high metal content can avoid undesirably high shrinkage during sintering. A major advantage of the conductive composition of matter for metallizations according to the invention occurs when one has to metallize closely adjacent holes in MLCs. In this case, in the prior art, for example Use of molybdenum for the metallization often in Sin-! tern to cracks in the ceramic material between the holes came. With the conductive material composition for metallization according to the invention, in particular the composition of matter particularly suitable for the metallization of bores of Example 1, the formation of such cracks is avoided.

Example 2

Following the procedure of Example 1, it was described below electrically conductive material composition for metallization with a solid matter content of 83

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weight percent and a content of binder of 17 weight percent formed.

Solid constituents binders

(% By weight) (% by weight)

Sä SS UUS ³ SIf§ ^{hes Ma} * erial _{same values as}

8.7 77.9 13.4 Example 1

The ruthenium and molybdenum had the same properties as in Example 1. The ceramic material with the glass had the following properties;

89% by weight of alumina frits

11% by weight aluminosilicate glass frit with the composition ί

CaO 7.10

MgO 8 _f 85

SiO ₂ 54.90

O ₃ - 29 _f OO

The ceramic platelets were formed as in Example 1, j

Following the procedure described in Example 1, the conductive Composition of substances for the formation of the surface metallization and the internal metallizations including the filling of the holes. The composition of matter According to the present invention, which contains a ceramic material, has been screen printed to apply a solder support point 1.5 mm in diameter and 0.0254 mm thick is used directly on one of the holes.

The structure produced in this way was then treated exactly as in Example 1, except that in the present example after sintering Terminal pins were soldered to the soldering post, and

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as follows: Palladium was applied electrolessly to the metallization of the connection with a thickness of 0.075 mm. A The wettable pen was made using a gold-tin alloy soldered to the palladium.

Upon examination, it was found that the stick adhered to the substrate excellently, and no cracks or cracks were found Distortions of the substrate under the metallization were found.

The resulting module is shown schematically in FIG. 2, which differs from the module created by example 1 only in the parts that are required for soldering or welding on a pin. The module is denoted by the reference number 20, the sintered ceramic layers, although they are already in monolithic form, are denoted by 21, the surface metallization with 22, the internal cable runs with 23, the metallized bores with 24, the metal-ceramic-glass connection with 25, the electroless palladium metallization with 26, the gold-tin solder with 27 and the pin with 28. Although the ceramic material was identical for substrate and metallization, one could have used different ceramic materials _f and one would also have mixtures of ceramic materials can use for the substrate and / or the metallization. In general, it will not be preferable to use mixtures of ceramic materials.

The metallization shown in Example 2 can be used to advantage, in particular, when it comes to excellent adhesion goes.

Example 3

Following the procedure of Example 1, the following was made conductive material composition for metallizations with manufactured with a solid component content of 80% and a binder content of 20%,

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Solid constituents binders

(% By weight) (% by weight)

Ru Mo solvent binder wetting agent 10 9O 75 20 5

The ruthenium, molybdenum, solvent and wetting agent were the same as in Example 1. The binder was ethyl cellulose, the binder had a viscosity of about 30,0OO cp.

The procedure of Example 2 was observed in all respects, with the exception that the conduit shown in FIG. 1 was applied by screen printing 12 _f using a conductive material composition according to the present example.

Results equivalent to Example 2 were obtained, but the higher viscosity of the binder allowed one more precise screen printing to form very fine lines, for which the conductive material composition for metallizations according to Example 3 is particularly suitable.

Example 4

This example shows the formation of a graded MLC.

Following the procedure of Example 1, the following conductive metallization composition is formed.

Ruthenium compound the same as in Example 1, only that

all molybdenum has been replaced by ruthenium. !

Ru / Mo graded composition of matter: the same as in ^! Example 1·

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Molybdenum compositionχ the same as in Example 1 except that

all ruthenium has now been replaced by molybdenum.

These compositions of matter were used for a gradation of the metallization in the MLC from pure ruthenium on surface j via ruthenium / molybdenum to an internal molybdenum metallization used by metallizing the ceramic foils to form the final module according to the following flow chart. In this context, the Explanation referring to Fig. 3, in which the module formed by this example is shown schematically in cross section and

is provided with the reference numeral 30. ]

Although the module is basically a monolithic one after sintering Structure, the model of a graded MLC can best be seen by looking at the ceramic Illustrate foils in such a way that they are still individually distinguishable, i.e. as if they were just piled up and still are not laminated.

The two outer ceramic foils A and J are made using a metallic mask as a template Holes 31 provided and the surface metallization 32 is using the ruthenium material composition through sieve I pressure applied ·;

The next two ceramic foils B and X will be the bores 33 are filled in via a metal mask as a template using a material composition of ruthenium / molybdenum. The ceramic foils C, E, G and H are provided with holes 34 and then using a metal mask as a template and provided the molybdenum material composition with a metallization «

The ceramic foils D and F receive holes 35 and these

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are stenciled with the molybdenum material composition through a metal mask filled in, while the line 36 by screen printing also with the molybdenum material composition is applied. The module shown schematically in FIG. 3 accordingly has three graduated metallizations, starting out from a ruthenium metallization at 31, 32 to a ruthenium Molybdenum metallization 33 to a molybdenum metallization at 34.

The gradation of a ruthenium metallization on the surface over a ruthenium-molybdenum and a molybdenum metallization inside has the following advantages »Ruthenium is very resistant to high temperatures, high humidity and harmful environmental influences and serves as protection for the Molybdenum, the molybdenum * that forms the bulk of the metallization, is cheaper than ruthenium and therefore reduces the cost of the module,

The graduated area between ruthenium and molybdenum metallization avoids possible difficulties with a smooth meeting of the two metals when sintering Ruthenium and molybdenum directly collide, D, h ,, during sintering there would be a separation between these two metals occur, so that there are bad within the metallization Conductivity can result.

All process conditions and materials used with the exception of the composition of the conductive material compositions were exactly the same as in example 1

When testing the module produced in this way, results equivalent to those of Example 1 were obtained. According to the test procedure Example 1 gave excellent results, i.e. excellent resistance to high temperatures and high humidity.

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Although a surface metallization in the above-mentioned embodiment As shown in pure ruthenium, such a graded metallization can be achieved with all metallizations perform whose ruthenium content is greater than 80 percent by weight. The remainder, if any, generally consists of Molybdenum and / or tungsten.

The gradation represents a metallization, the metallic components of which, as already indicated, are approximately 5 to 40 percent by weight Ruthenium and the remainder of molybdenum and / or tungsten in any ratio, regardless of whether the internal metallization consists of molybdenum or tungsten.

Example 5

Example 1 was repeated with the exception that instead of the metallic components used there, 75% tungsten and 25% ruthenium were used. Good results were obtained, the resistance change after a test at 85 ⁰ C and 81% relative humidity at a test period of 1,000 hours was less than 1%,

Example 6

Example 4 was made again, but the surface metallization was replaced by the solder terminal of Example 2 and the terminal pin described in Example 2 became soldered on.

Excellent results were obtained as in Example 4, and the stick showed exceptionally good adhesion on the hole below, filled with ruthenium.

Example 7

The procedure of Example 1 was repeated with the exception that the surface metallization was not applied to the prior to sintering

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the outermost ceramic substrate was applied by screen printing.

After sintering or firing, the surface metallization was applied to the fired module by screen printing, as in the example 1 dried and the module metallized in this way sintered according to the sequence of example 1.

The resulting module was essentially that of Example 1 equivalent, in which the various metallizations were sintered together.

Although screen printing or metal mask stencils are generally used for simultaneous sintering of metallizations used, the metallization can be on an already sintered ceramic substrate, for example a module, Apply in such a way that the material is first brushed on, sprayed on or distributed by spinning, or through Applying cathode sputtering, or by applying the material in powder form, for example if a hole is made in a already fired or sintered ceramic substrate is to be metallized,

Example 8

The procedure of Example 4 was repeated except that the surface metallization from the. conductive metallic Composition of matter of Example 1 instead of the ruthenium composition of matter of example 4 was produced and that all internal metallizations (holes and cable runs) formed from the molybdenum composition of matter of Example 4 became.

Excellent results have been obtained, showing that that the metallization according to the present invention as a surface metallization to protect an interior from Molybdenum existing metallization can be used and

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is compatible with this.

Example 9

The procedure of Example 8 was repeated with the exception that instead of the surface metallization in Example 8, the solder terminals according to the procedure of Example 2 were applied. After soldering on a pin as in Example 2, the Check that the pin adhered excellently to the substrate and the hole filled with molybdenum. The results showed therefore suggest that the ceramic / conductive metallic compositions of matter of the present invention are compatible with this when adhering to a molybdenum metallized bore.

In all embodiments of the invention, one provides on ruthenium built-up metallization has a high resistance to high temperatures and high humidity as well as harmful Environmental influences. A ruthenium-based metallization is the metallization made of molybdenum, tungsten or Molybdenum-tungsten in its resistance to harmful environmental influences, such as Sg, sulfur dioxide, ammonia, chlorine, Superior to hydrogen sulfide, nitric oxide, and nitrous acid.

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Claims (18)

PATENT CLAIMS 1. Conductive material composition for metallizations for
Application and sintering on a ceramic dielectric to form electrically conductive elements and coatings, j characterized by a homogeneous mixture of ruthenium | and molybdenum and / or tungsten, 2. A composition according to claim 1, characterized in that about 5 to about 40 weight percent ruthenium on \ based on ruthenium, molybdenum and / or tungsten
are included « 3. A composition of matter according to claim 2, characterized in that about 95 to about 60 percent by weight of molybdenum
and / or tungsten are contained together with about 5 to about 40 percent by weight of ruthenium, 4. The composition of matter according to claim 3, characterized in that that the ruthenium content is between 8 and 25 percent by weight * 5. The composition of matter according to claim 2, characterized in that that also a dielectric, ceramic materiali included 1st, 6. A composition according to claim 5, characterized in j-net that the proportion of the ceramic material is no longer \ than 75 percent of the total volume of dielectric
ceramic material, ruthenium, molybdenum and / or WoI- .fram is. FI 973 075 609887/1038 7, composition of matter according to claim 6, characterized in that that the proportion of dielectric ceramic material from about 5 to about 50 volume percent of the total volume amounts to. 8, composition of matter according to claim 7, characterized in that that the dielectric ceramic material is selected from a group consisting of alumina, mullite, berryllium, Consists of titanium, fosterite, zirconium and steatite, 9, composition of matter according to claim 8, characterized in that that alumina is used as dielectric ceramic material, 10, composition of matter according to claim 7 _f, characterized in that about 5 to about 20 percent by volume of the ceramic material is replaced by glass, 11, composition of matter according to claim 10, characterized in that that the glass is an alumina silicate glass, 12, composition of matter according to claim 1 _f, characterized in that a thermoplastic resin is also included as a binder, 13, composition of matter according to claim 12, characterized in that that the binder contains a volatile solvent, 14, composition of matter according to claim 13, characterized in that that the content of solid components is between 80 and -90 percent by weight, 15, Application of a composition of matter for metallization multilayer, ceramic modules for the production of cable runs on the outer surface and in the FI 973 075 509807/1038 Inside the module, characterized in that the outside Metallization consists of at least 80 percent by weight of ruthenium, that the further inside Metallization consists of molybdenum and / or tungsten and that the internal metallization is at least a zone in the vicinity of the surface metallization consists of ruthenium and molybdenum and / or tungsten. 16. Application of the substance composition according to claim 1 to 15 to a multilayer ceramic module with external and internal metallization, characterized in that that the internal metallization consists of molybdenum. 17. Use according to claim 16, characterized in that the remaining proportion of the metal of the inner metallization consists of tungsten. 18. Application according to claim 17, characterized in that the inner metallization consists of tungsten. FI 973 075 509887/1038