JPS6016885A - Metallization of ceramic - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to metal-plated ceramic articles, and
The present invention relates to metal-plated conductor patterns bonded directly or adhesively onto the surface of a ceramic substrate, and to an improved method of manufacturing the same. More particularly, the present invention relates to printed circuit patterns directly but adhesively bonded onto the surface of a ceramic substrate, using a substance in a molten state to promote adsorption of a catalyst in a metal plating reservoir. The present invention relates to an improved method of manufacturing a sump.

Prior Art A metal-plated conductor pattern on a ceramic substrate is
It has been widely used in the electronic industry. For many years, molten metal-
Ceramics have been metal plated using high cost methods such as galanuvene and thin film bonding techniques. Attempts to reproducibly create circuit patterns by direct electroless plating have been unsuccessful due to poor adhesion of the metal film to the substrate and reproducible and uneven surface coverage.

Printing time #5 on ceramic containing alumina is 19
It was already published in 1947. One system, known as thin film circuitry, consists of a thin film of metal deposited onto a ceramic substrate by a type of vacuum plating technique. In this method, a chromium or molybdenum film having a thickness of approximately 0.02 microns serves as a binder for a copper or gold conductor reservoir. Photolithography is used to create high resolution patterns etched from thin metal films. Such conductive patterns can be electroplated up to 7 microns thick. Due to the high loft, thin film circuits have been limited to high frequency and military applications requiring high resolution patterns.

Another type of printed circuit, known as a thick film circuit, consists of a metal and glass film baked onto a ceramic substrate. Typically, the membrane has a thickness of about 15 microns. Thick film circuits have been widely used. Thick film in organic gear? [Manufactured by Nuclean printing on a circuit pattern with a base containing conductive metal powder and glass frit.]

After printing, the ceramic part is fired in an oven to burn off the carrier, sinter the conductive metal particles, and melt the glass, thus forming a Galanu metal stand-up conductor.

The electrical conductor is firmly bonded to the ceramic by the glass, so that components can be connected to the electrical conductor by soldering, wire bonding, etc.

The electrical conductors in thick film circuits have only 30 to 60 percent of the conductivity of pure metals. The high electrical conductivity of pure metals is required to provide the interconnections of high speed logic circuits. The conductors in thick film circuits do not have such high conductivity, so
They do not provide optimal interconnection of high speed logic circuits.

The minimum conductor width and minimum conductor spacing obtained by screen printing and baking in a particularly high quality manner are 1.25 and 2oO microns, respectively. However, under normal manufacturing conditions, these minimum values are 200 and 250 microns, respectively. Multilayer methods are used for ceramic circuits requiring high interconnect density or high connectivity.

In the thick film multilayer process, a first layer of metal powder and glass frit is printed onto a ceramic substrate and deposited in a furnace, typically 8
Can be baked at 50″C.

An insulating dielectric layer is then screen printed over the conductor pattern, leaving only the points exposed where contact will be made to the next metal plating layer. This dielectric pattern is also baked at 850"C. A second dielectric layer is then printed and baked. The two dielectric layers must be printed and baked to ensure there are no pinholes. The two dielectric layers After the dielectric layer is printed and baked, the next conductor layer is printed and baked to make contact with the underlying conductor layer, if necessary, through apertures left in the dielectric layer.

A typical multilayer ceramic package includes two to six metal plating layers. Eight layers are not uncommon. For two layers of metal plating, the board was printed 4 times and 4 times 85
Baked at 0"C. On a 3-layer metal plating reservoir, the board is printed in 7 turns and baked at 850"C. and 10 for 4-layer thick film multilayer ceramic.
times. According to the method of the present invention, the same connectivity as a three-way four-layer multilayer ceramic can be achieved with a conductor pattern plated through holes on one and both sides.

In order to achieve high electrical conductivity in ceramic based circuit patterns, attempts have been made to bond pure metal conductors directly to ceramic substrates containing alumina. - (U.S. Pat. No. 3,744,120 and U.S. Pat. No. 3,7
66,634). U.S. Patent No. 3,994,43
No. 0, etc., discloses a method of bonding copper to alumina by heating copper in air to form an oxide film on the surface. The copper sheet is then bonded to the alumina through this coating in a nitrogen furnace at a temperature between 1065"C and 10'75"C. In order to obtain a well-adhered copper 2^ without bubbles, 2],)
The copper foil must be carefully oxidized at the neck resulting in a black surface. The thickness of the copper oxide must be carefully adjusted; 3) The amount of oxygen in the copper foil must be adjusted;
4) The amount of oxygen in the nitrogen furnace must be kept at a regulated level to maintain a very mildly oxidizing atmosphere, and 5) The temperature must be regulated to within 1 percent. This ultra-high temperature operation is difficult and expensive to tool, operate, and control.

If the very tight controls described above are not maintained, air bubbles and other poor adhesion of the copper foil to the substrate will clearly occur. Despite the difficult operating conditions, these methods are being introduced into commercial applications due to the demand for metal plated products.

Although the synutems described above are in commercial use, simple metal plating of ceramics with pure metal conductors such as copper inspired a series of patents and proposed prosenuses. For example, German Patent No. 2,004,133
German Patent No. 2°, 453,192, German Patent No. 2.4.53, 27.7. See also US Pat. No. 3,296,012, which discloses a method of creating a microporous surface for non-electroplating alumina. Attempts to simply apply electroless metal plating directly to ceramic substrates have continued, but have never been commercially successful. Even potent and corrosive substances such as hydrogen fluoride have been tried to directly bond metals non-electrically without extreme baking temperatures (J, EI).
ectrocl+em, Soc.

120.1518 (19'i'3)). However, the hydrogen fluoride etching weakened the strength due to excessive impact on the ceramic surface.

Another attempt, disclosed in a US patent, involves sensitizing the surface with a stannous chloride sensitizer, activating the surface with palladium chloride, and first etching the ceramic surface before non-electroplating the surface. molten sodium hydroxide. Although the sodium hydroxide etch provided good bond strength to the metal coating, it never achieved commercial production. The problem was poor surface coverage of non-electrodeposited metals. Although the metal layer typically covered 90% or more of the surface area, this was insufficient. Any defect in the metal film will result in an open circuit or complete lack of operation if the defect occurs in the fine wire conductor pattern.

US Pat. No. 4,428,986 discloses a method for the direct autocatalytic plating of metal films onto Beryliya. This method involves soaking Berilya in 50% sodium hydroxide solution at 250°C for 7 to 20 minutes to make the surface of Berilya uniformly rough, washing with water, and etching the surface of the Berilya substrate with fluoroboric acid for 5 to 2Q minutes. and washed with water, soaked beryllia in 5g/4 stannous chloride solution and 3N hydrochloric acid, washed with water, ○. 19/(l) It consists of treating the beryllium with a palladium chloride solution, washing with water and then electrolessly plating nickel on the beryllium. However, the etching step removes silica and magnesium from the beryllium treatment border, weakening the beryllium surface. As a result, this method produces only 250 bonds per square inch (1,'i'
Only a bond strength of MPa) is achieved. This coupling strength is small, about one-third of the coupling strength typical for thick-film circuits.
It is.

Other methods of forming printed circuit patterns on ceramic substrates are described in U.S. Patent No. 3. '772,056, No. 3
9'7”i' No. 2,078, No. 3.90 '7,62
No. 1, No. 3,925,578, No. 3,930,903
No. 3,959.54 'i' No. 3,993. s
... No. 02, and No. 3,994. It is disclosed in 'i' 2 '7.

However, these patents do not teach how to solve the problem of poor surface coverage and inadequate bond strength of ceramics.

Ceramic packages have been widely used to protect microelectronic circuits, such as integrated circuits and hybrid circuits, from contamination by the outside environment.

A seal is required between the ceramic substrate of the package and its cover to exclude the outside environment.

To date, hermetic seals have been provided for ceramic dual-in-line packages used in the microelectronic industry by the following method. In one method,
A refractory metal paste, usually Moly Manganese, is applied to the ceramic substrate. In order to fuse the moly-manganese alloy to the ceramic surface, the paste and ceramic substrate were heated to 1500 to 18
The refractory metal alloy is then plated with gold, or nickel and gold. The microelectronic circuit is inserted into the ceramic cavity through the opening in the substrate. are connected to fill holes provided in the substrate.

The opening in the ceramic body is hermetically sealed by covering it with a soldered cover around the opening.

A gilded copal lid or a ceramic lid with a gilded moly-manganese surface is used as the cover.

Soldering is performed in a nitrogen atmosphere using gold-silk solder or gold-silver antimony solder. Although this method can produce a good hermetic seal, it has the disadvantage that it is extremely expensive due to the difficulty of plating the refractory metal and the extremely high deposition temperatures.

Epoxy adhesives have also been used to provide a seal between the ceramic package and the package indigo. This method is unsatisfactory because organic vapors from the epoxy sealant l- can contaminate the microelectronic circuits.

Forms a hermetic seal for ceramic package reservoirs,
Yet another method is to use a low melting point glass applied as a glass paste with a carrier solvent.

Galanuveneto is applied to the sealing surface of the ceramic package and then melted in a furnace. This method is less turbulent because it encapsulates the solvent from the glass paste inside the package along with some of the glass itself.

The high reliability of the circuit can be destroyed due to contamination by solvents trapped within the glass interlayer.

OBJECTS OF THE INVENTION An object of the present invention is to apply a metal film to a ceramic substrate,
The object is to provide a method for obtaining excellent surface coverage and a bond strength of at least 3 MPa, preferably at least 5 MPa.

It is an object of the present invention to create a metal plated ceramic substrate that can be used in fine line circuit applications with high purity metal conductors.

It is an object of the present invention to provide a method for making non-electrically attached, directly bonded conductors and metallized ceramic substrates with excellent adhesion to ceramic substrates.

It is an object of the present invention to provide a plated ceramic substrate and a method for making a plated substrate with missing electrical conductors in the interconnects of high speed logic circuits.

It is an object of the present invention to provide a double-sided plated ceramic substrate with a through-hole conductor pattern and conductor density comparable to three or four layer thick film multilayer ceramics.

It is also an object of the present invention to provide a method of joining ceramic articles or other plated ceramics by soldering, brazing or welding. .

Structure of the Invention The present invention is directed to a method for forming a metal film on a ceramic substrate containing alumina, and is directed to a method for forming a metal film on a ceramic substrate containing alumina.
It has excellent surface coverage and bond strength (ie, at least 3 MPa, preferably at least 5 MPa) as measured by the "pull test".

The present invention also includes ceramic substrates having printed circuit patterns formed from such coatings. Ceramic substrates - at least 0.2 microns,
Preferably a metal deposit having a thickness of at least 2 microns is obtained, which typically has a conductor shape having a width of no more than 25 microns, preferably 50 microns.

The process of the invention consists of the following steps: (a) treating or adhesion promoting the surface of the ceramic with at least one molten inorganic compound; (1) applying the adhesion promoted surface to the treated surface -\; It is brought into contact with a solution capable of promoting catalyst adsorption and deposited during the day.

In other embodiments, the process of the present invention also includes bonding the gold plated ceramic substrate with metal and yet other metal plated ceramic substrates by soldering, brazing, or welding. .

According to the present invention, any metal film can be deposited on the surface of the ceramic substrate. Typically, metal films of copper, nickel, silver or cobalt are electrolessly plated.

The ceramic surface is first treated at high temperatures with a substance that provides the etched surface necessary to create a strong bond between the deposited metal layer and the ceramic substrate. Preferred materials for this purpose are at least one alkali metal compound in the molten state. Preferred alkali metal compounds include hydroxide l-
'Jumium, potassium hydroxide, sulfur and lithium carbonate and potassium nitrate, and potassium hydrogen sulfate.

A proposed method for etching with molten alkali is shown in U.S. Pat. Many alkali metal compounds are suitable for promoting adhesion of ceramics, such as etching. It is preferred to use compounds with low melting points. As an alternative, preferably up to about 50% by weight of a low melting point substance or liquid is incorporated into the alkali metal compound. The melting point of the alkali metal compound may be lowered by dissolving the compound at a concentration of 20% by weight. Examples of such melting point lowering agents include sodium chloride, nitric acid, water, sodium and potassium formate, potassium acetate, It is believed to contain V4, borax, and hydrates of lithium bromide, iodide, and phosphate, and potassium pyro9ophosphate.

At times it may be preferable to avoid hydroxides for safety and ease of neutralization. Representative alkali metal compounds suitable for use in the present invention and their melting points are listed in Lang's Chemistry Handbook, 11th Edition (19'i'2
) and is as follows.

1 Touch Point C Co-mixtures such as a mixture of potassium hydroxide and sodium hydroxide or a mixture of sodium carbonate and potassium nitrate can also be used to etch the substrate. Mixtures of the former type preferably have a weight ratio of KOH to NaOH of 59.
:41 and has a melting point of ]70″C.

Typical ceramic substrates etched by the molten compounds used herein include 7/l/min.
Silicates, beryllia, titanates, humelstellite, mullite, nutequite, porcelain and mixtures thereof.

Typical metal plating solutions used are electroless, plating solutions such as nickel, cobalt, gold and copper (
U.S. Patent No. 3,485,643, No. 3,607-17
No. 3,589,916, etc.). Electroplating solutions are also used in the practice of this invention.

In the method described by Elmore, sodium hydroxide is washed from the ceramic surface with water, the ceramic surface is then neutralized with dilute sulfuric acid, washed again with water, the surface is sensitized with stannous chloride, and the ceramic surface is washed with water and electroless. Seeded with palladium chloride to catalyze for metal plating.

This method is unreliable and often results in incomplete surface coverage with non-electronically generated metal deposits. This condition is completely impractical. With prolonged immersion in both the stannous chloride sensitizer solution and the palladium chloride seeding solution, and with an incomplete water wash step, it is sometimes possible to obtain complete surface coverage with metal.

However, this stage is not practical for production.

Prolonged immersion in the sensitizer hinders the economical performance of the work, and incomplete water washing after stannous chloride leads to poor adhesion formed in the seeding solution and in the electroless plating solution. This results in precipitated particles and rapid decomposition of these solutions.

The use of a single catalyst solution prepared from both stannous chloride and palladium chloride is well known in the art of printed circuits and plating on plastics. Representative catalyst solutions are shown in US JF/L No. 4.18 'i', 198 and US Patent No. 3.96.1°109.

Such a catalyst solution can be used more advantageously in ceramic plating than the two-step sensitized seeding solution described by Elmore.

The inventors have discovered that sensitizing species (Sensitilizing 5 species) are adsorbed onto the ceramic surface and distributed over the entire surface.
By treating the etched ceramic surface with a compound that promotes the adsorption of metals (tfU) and, surprisingly, gives a complete coverage, the surface can be treated with a species that makes the surface receptive to metals (t fU, i.e. sensitizers, species Adsorption of the sensitizer or catalyst and, ultimately, the surface coating of the metal has been found to be greatly promoted. Compounds that are adsorbed and promote adsorption of the sensitizer include single chlorides, bromides, and There are iodides and complexes of chlorides, bromides and iodides.

The invention is further illustrated by describing the use of acidic chloride, bromide and iodide solutions greater than 0.5 molar as the halide to promote uniform adsorption onto the ceramic surface. These acid halide solutions do not attack the glass phase of the ceramic substrate.

Acidic chloride, bromide or iodide solutions may be used as pre-treatment or pre-soak solutions after adhesion promotion, washing, neutralization and re-washing; and before treatment with e.g. stannous chloride sensitizers. I can do it. After such pretreatment, the sensitizer is quickly adsorbed onto the etched ceramic substrate and is reliably adsorbed, so that it cannot be inadvertently removed even during conventional water washing steps.

Preferably, the acidic chloride, bromide or iodide presoak or pretreatment solution contains more than 2 moles of halide ions, more preferably 3 moles of halide ions.
More than moles. The acidity of the halide solution is preferably
More than 0.001 moles as hydrogen ions, more preferably more than 0.01 moles as hydrogen ions, most preferably between 0.1 and 12 moles as hydrogen ions.

Alternatively, the inventor may increase the chloride, bromide, and iodide concentrations of the sensitizer solution to achieve a similar effect, i.e., stronger sensitizer adsorption onto the ceramic substrate. I discovered that.

High acidity prevents adsorption of the tin sensitizer. The halide to acid ratio in the stannous ion sensitizer is preferably at least 15:1. Lower ratios, such as a 2 to 1 halide to acid ratio, may be used, but this is not preferred as it requires a high g concentration, i.e. 17 g.

Although we do not wish to be bound by theory, in the case of tin-containing solutions, the beneficial species adsorbed onto the alumina is the tetrahalostannate moiety.

For example, high chloride ion concentrations relative to acidity favor the formation of tetrachlorostan(It) salts, whereas high acid concentrations favor the formation of trichloro and dichlorostan(II) salt complexes. For example, the stability constant of metal ion complexes,
5 pec, pub 17.

5illen and Martel, The Ch.
emical 5oci-ety, London (
1964), pp. 296-7.

When using a single catalyst solution consisting of palladium chlorides, bromides, or iodides, tin and halides, acidic or alkali metal halide salts without an acidic halide presoak solution, the halide concentration is ○o5 The acidity may vary from 0.03 to 6 mole/l, but preferably more than 1.5 mole/l, preferably less than 4 mole/l. /1//β, but preferably more than 0.37 l/l;
Preferably less than 4 mo/L//β.

In order to increase machining tolerance and minimize machining errors,
Acid halide pretreatment may be combined with a sensitizer solution formulated with halide and acid concentrations according to the invention.

Additionally, acid halide presoaks may also be used with a single catalyst solution.

By using an acid halide pre-soak, the first
Other catalytic noble metals or metals can be adsorbed to the ceramic surface, including Group A metals, silver and gold, and other Group 1 metals.

Numerous processes are used to manufacture printed circuit boards.

As will be readily understood by those skilled in the art, these printed circuit manufacturing processes can be combined with the adhesion promotion step of the present invention to produce metal-plated ceramic printed circuit boards, and also metal-plated ceramic surfaces. may be used in combination with the step of making it acceptable.

In accordance with the present invention, articles and methods are formed that provide a hermetic seal of gold r7AN to a ceramic substrate. The present invention
Provides a hermetically sealed ceramic package for microcircuits and other uses. Additionally, the process of the present invention provides a method for applying an adhesive metal film to a ceramic surface, in which metal-plated ceramic surfaces are bonded together by standard metal bonding techniques such as soldering, brazing, and welding. It can be used to bond or bond a dimensionally metal-plated ceramic surface to a metal article.

As used throughout this specification, a “hermetic seal” (HEPM
The word M I f, -
S TD-883T3, Method 1014
, 3 (May 16.1 (1'i'9) fine leak tests).

As those skilled in the art will appreciate, these hermetic seals adorn hybrid packages, chip carriers, bond circuit packages, flat packs, dual-in-line packages, and optoelectronic packages. In forming a hermetic seal on a ceramic substrate according to the process of the invention, the surface of the ceramic substrate is first provided with a metal layer by the method described above. The metal layer on the ceramic surface is then bonded to the metal or other gold lfi plated ceramic substrate by standard metal bonding techniques, typically soldering.

Other embodiments of carrying out the invention are disclosed inter alia in the Examples.

Example [■] This example shows how a pre-soak containing chloride or bromide provides uniform surface coverage.

0.5■+ containing 90% alumina (the rest is other oxides)
A thick flat black ceramic substrate was washed with 7)V caustic cleaning solution (BA, SF-Wyando+le).

1 at a temperature of 60"C in Altrex, commercially available from
Adhesion is promoted by soaking for 0 minutes.

The substrates are then rinsed with water at 25° C. for 1 minute, immersed in sodium hydroxide solution (7609/e), removed and drained. The resulting wet ceramic substrate is placed on the edge of the support fixture. Next, the substrate was dried at 1'75'C for 10 minutes to remove moisture in the sodium hydroxide film on the substrate, and then heated in an oven at 450°C for 15 minutes to hydrate it. melts the aluminum, roughens the surface and promotes adhesion. Wait for 5 minutes and then wash the ceramic board with water.
After rinsing in 0% sulfuric acid at 25°C for 2 minutes, an adhesive copper coating was electrolessly plated in deionized water as described in Section 25.

a) Soak for 2 minutes at room temperature in the 11 chloride or bromide dipping solution shown in Table 1.

0.12mo) V Immersion for 10 minutes at room temperature in a sensitizer solution consisting of 59 g of stannous chloride dissolved in 1β hydrochloric acid solution.

C) Rinse with deionized water at room temperature.

d) 0.0 ], 2-c-Jv Immersion for 2 minutes at room temperature in an active agent solution of 0.1 g palladium chloride dissolved in 1 l of hydrochloric acid.

e) Copper sulfate 10 9/1 Ethylenecyamine titraformaldehyde 6 g/l Block copolymer wetting agent 10 yn9/12 Thorium cyanide 10 mfl/1 Sodium hydroxide at pH 13 Kj at room temperature Plate for minutes.

The effect of a halide pre-dip on the surface coating of a ceramic substrate is shown in Table 1.

Table 1 None Acceptable or some bare spots 2 1, 2 MHCl Unacceptable or some bare spots 3 4 M l-ICβ Complete metal film 4 6 MHCl
Complete metal film 5 9M1-IC1 Complete metal film 6 12MHCβ Complete metal film '7 1M NaC, 5pi-1 <:t Acceptable, poor, some bare spots 8 3.4M NaC4 pH < 1 Good - complete 1 mK film 9
5M NaBr pH (L good - complete metal film 103
．． 8MNa (4 Good - complete metal film ○, cMI- (CI Q, 25M5nC42) An unacceptable coating has good color and adhesion but some skipped plating or copper deposits with bare spots By complete metal coating we mean a copper coating with good color and adhesion and complete coverage with no bare spots or skipped plating.

In all cases, the adhesion of metal to ceramic was excellent, even with incomplete surface coverage.

EXAMPLE [■] This example shows the effect of pH of the halide pre-soak solution.

The halide pre-soak solution and the results obtained were used in the first example [■] except where indicated in the table.

Table 13゜8M NaCβ pH (↓ Good - Complete metal film 2
3, sr~iN; +C summon, QH: 5 Uke is receiving row 1
Ichiwakasen's exposed spots 3 3 . 81! The method of Example [■] was repeated except that the halides were omitted and the sensitizing solution of step (1) was modified with sodium chloride. .

The sensitizer solution was: stannous chloride 5o g/12 hydrochloric acid s mt/(1 sodium chloride 180g/β) In other words, by increasing the chloride concentration in the sensitizer solution compared to Example (I), another halide 11J immersion solution step was obtained. Complete coverage of the ceramic substrate with the copper film is achieved without the use of copper film.

This example further illustrates the importance of halide concentration in the ceramic pretreatment step prior to electroless plating.

Ceramic substrates are adhesion promoted in a manner as in Example (I).

A catalyst concentrate was prepared according to the method disclosed in US Pat. No. 3,961,109. Paranrum chloride, m chloride
- An aqueous solution containing thorium chloride, hydrochloric acid and resorcinol is prepared and heated to 7 Irl. After cooling, the solution was washed with additional sodium chloride, sodium chloride, and hydrochloric acid to obtain a standard C thick catalyst solution. 1 ml of this concentrated liquid
] to obtain a catalyst solution for actual use.

For a catalyst solution with a high chloride content, 31 ml of the concentrate was diluted with a solution of 3.8 m)V sodium chloride, 0°11 m)v hydrochloric acid and 0.025 mz+/dichloride. . For a low chloride catalyst solution, 31ynl of the concentrate was diluted with a 0.18 molar sulfuric acid solution. 31 ml of the 'a thick solution was diluted with a 0.36 m/V hydrochloric acid solution and an o, 36 molar hydrochloric acid solution with 1 molar sodium chloride added, respectively, to prepare two types with medium chloride concentrations. A catalyst solution was prepared. These four catalyst solutions had the following compositions.

Chloride: High Medium Low Palladium 0.15 0.15 0.15 0.15
Stannous chloride 23 18 18 18 Sodium chloride 226 63°85°65°6 Water chloride purple 4°611°7 11.7 0.6 Resorcinol 1
．． 2 1+2 1.2 1.2 Total chloride 150 56
21 10 These catalyst solutions are stable, active catalysts and are widely used in the plastic plating industry for the production of printed circuits with plated through holes using bulk epoxy resin laminates.

The etched ceramic substrate was metal plated in the following manner.

1) Immerse the substrate in the catalyst for 5 minutes at room temperature.

2) Wash with deionized water.

3) Soak in an accelerator solution consisting of 3% fluoroboric acid in water.

4) Wash with deionized water.

After electroless metal plating, the substrates contacted with a high halide catalyst and a medium catalyst containing 56 crumbs/4 chloride were completely coated with a uniform film of metal, whereas the substrates with low halide Ceramic substrates contacted with medium catalyst and chloride containing only 21 grams/β became skip plating, ie, had small areas of ceramic without copper plating.

EXAMPLE (V) The adhesion of electrolessly plated gold films to ceramic substrates was tested in a "dot pull test".

Instead of plating the substrate with the electroless copper solution of Example CI) at room temperature, the following substrate was plated so as to deposit 10 micrometers of copper on the substrate.

Ethylene dinitrilotetra-2-propatur 18'f/l Copper sulfate pentahydrate '10 g/β Formaldehyde 1°6! /l Wetting agent" 0.01 9/β Sodium cyanide 25 mg/(12-mercaptobenzothiazo-/I10.0177+ 9/l Sodium hydroxide to pH 12.8 Temperature 52°C *Gafac RE610 from GAFCorp Nonylphenoxypolyglycide-/l/phosphate ester substrates, commercially available as Nonylphenoxypolyglycide-/l/phosphate ester substrates, were adhesion promoted in the same manner as described in Example (I).

Adhesion promoted ceramic substrates were metal plated in the following manner: 1) 3.8 moles of sodium chloride per 14, ○.

Soak for 2 minutes in a room temperature aqueous halide presoak solution containing 1M hydrochloric acid and 0.025M stannous chloride.

2) Add 15% to the chloride-rich catalyst solution of Example [Ba] at room temperature.
Soak for minutes.

3) Wash with deionized water.

4) Immerse in the accelerator solution of Example [Ba].

5) Wash with deionized water.

6) Plating with non-electrocontoured deposition solution.

7) Rinse and dry.

The substrate was then imaged and etched using conventional photolithography to create copper dots 2.5 microns in diameter. An electric wire was soldered to a copper dot, and when the dot was torn off from the ceramic surface, an average bond strength of 10.8 MPa was measured.
10 minutes in a molar hydrochloric acid solution, a 1 minute rinse in deionized water, a 10 minute rinse in deionized water, a 0.1 molar silver nitrate solution, a deionized water rinse, and a non-electrical metal adhesion solution of Example CI). 3
It was immersed for 0 minutes. The substrate was completely and uniformly coated with an adhesive copper metal film.

This procedure was repeated, except that after immersion in 3 molar hydrochloric acid and rinsing with water, the substrate was immersed in a 0.9 molar nitric acid solution for 2 minutes before being immersed in a 0.9 molar silver nitrate solution. The ceramic substrate was then washed with water and immersed in an electroless copper plating solution, but no copper adhesion occurred. A 0.9 molar nitric acid solution was tested for the presence of chloride by dropwise addition of silver nitrate.

A white precipitate formed. This indicates that the halides of the present invention are required on the ceramic surface to generate the catalytic silver sites (5ites) that initiate electroless copper plating, and that halides on the ceramic surface are easily removed by improper treatment. This shows that it can be removed.

This also suggests that since AlCl is less easily removed by water washing than 5nC12, insoluble 9cl is less likely to be present when the chloride ion concentration on the surface is low, i.e., when the halide presoak and h
This shows that the effect can be exhibited even with water washing between the gc4 catalysts.

Example (Vll) A white ceramic substrate was promoted by the method of Example [1]; it was immersed in a 3 molar hydrochloric acid solution for 10 minutes, washed with deionized water for 1 minute, and immersed in a 0.91 molar silver nitrate solution. , washed with deionized water and dried. Then, the two ceramic n plates were exposed.

The surface turned black, indicating that the adsorbed silver chloride was reduced by light and became a metallic silver seat.

Alternatively, silver chloride is reduced to silver with a reducing agent.

Example [■] Instead of a 90% alumina black substrate, alumina 96%,
The method of Example [■] was repeated except that a white ceramic substrate of O-4 thickness was used. Similar results were obtained.

Adhesion of a 96% alumina white substrate of 3Q 7JU

Then, it was coated with copper using the method described below.

1) Contains an amphoteric surfactant (tallow betaine surfactant), a nonionic surfactant (nonylphenoquine polyethoxyethanol) and exonolamine, pI-I
Immerse for 5 minutes in an aqueous regulator solution adjusted to 2.

2) Wash with water.

3) Soak for 2 minutes in the halide pre-soak solution of Example (V).

4. Immerse in the catalyst solution of Example [■] for 5 minutes.

5) Wash with water.

6) Copper is non-electrically deposited using the electroless copper solution of Example [J].

Sky I! i? A uniform copper coating without voids and skip gelation was obtained. Copper-clad ceramics are polyvinyl cinnamate polymers (Eastman
K commercially available from Kodak Company
PR), exposed and developed with KPR developer to obtain a negative resist image of the chip carrier on a copper clad substrate.

The exposed copper surface is the desired chip carrier pattern and is coated with a copper methane solution (L-ea Ronal,
C0I)I)-er commercially available from J-ITc,
Copper thickness 0. ○I IrLM-
Electroplated with 4. Next, 1 volume of Resis 1 is removed, and the non-electrical copper film on the side 1 of the chip carrier image pattern is removed by immersing it in thorium persulfate solution, thus fanning out to 0.36+IIJI+pitch 0. A finish 9 chip carrier with 132 conductors on a ゜l 4 +fZ#I pitch was produced.

Example (X) '7511L71+X'' 5 Vljl+, 0.47
90% alumina and 90% alumina
The method of Example (IX) was repeated for both 6% substrates.

In place of the chip carrier conductor strips, eight copies of the patterned conductor pattern for the hybrid circuit A,/I) (analog to digital) converter were fabricated on each board.

The hybrid circuit conductor pattern has 125 micrometer wide pure copper conductors, input/output connections, and interconnects for six integrated circuits and associated chip capacitors and resistors.

After removing the background non-electrical copper film and completing the circuit lean, each individual hybrid circuit is heated to 75 T by a laser.
The wafer force 1 of Im×'i'57'J+ was cut. Alternatively, individual circuit patterns are laser cut after the integrated circuit and chip resistors and capacitors are installed.

Example (n) Example [X] was repeated, except that the hybrid circuit conductor pattern was electroplated with nickel and gold over the electrically bonded copper. This resulted in a circuit with a clean, smooth pure gold surface that was better at bonding wires than a six-layer thick-film circuit printed with NuClean.

Example (Xl) Made on a 64 pinch tube carrier. A chip carrier was fabricated in the manner of Example [IX] except that the substrate was drilled with a 0.4 um diameter die cut hole and the conductor was plated on the back side through the conductor hole.

EXAMPLE (Xli) Additional hybrid circuit conductor patterns were formed by treatment with a ceramic substrate adhesion promoter and modifier, catalyst and example (Xli).
prepared by subsequent rinsing of the catalyst solution as in V).

Then dry the substrate and perform polymer dry photoresis)
(E, I. Ris+ commercially available from Dupont 7
on 1401) is applied to the substrate, exposed to ultraviolet light,
Developed in a conventional manner to form an image of the hybrid circuit conductor pattern.

Next, the substrate was tested (■) and 10 micrometers
A pure copper conductor pattern with a thickness of -/- is deposited. To complete the circuit, the background residue is removed with a solvent.

Example (XIV) Example (V) except that instead of the etched dot pattern, a hybrid circuit conductor pattern is produced by photolithography.
Don't change the method.

Example (XV) Adhesion of a 96% alumina ceramic substrate was promoted by the following method.

a) Soak in alkaline cleaning solution at 60°C.

1) Rinse with water.

C) Dry in a hot air oven at 160°C.

d) Soak the substrate in a molten solution of 205 grams of sodium hydroxide and 295 grams of potassium hydroxide at 210° C. for 10 minutes.

C) After cooling, wash with water for 5 minutes at room temperature.

f) Neutralize with 3M/I/hydrochloric acid solution for 2 minutes.

g) Wash with deionized water.

The adhesion-promoted substrates were then plated with adhesive cast steel coatings in the manner described in Example (IX) Steps 1-6. A uniform and adhesive copper coating was obtained without voids, blisters, bubbles and skip brating.

Example (XH 1) immersed in hot alkaline cleaning solution, 2) washed with water,
3) immersed in a 2.8 molar aqueous solution of potassium hydrogen sulfate; 4)
Dry the ceramic substrate in an oven at 160″C, 5)
Dissolve potassium hydrogen sulfate on the substrate surface at 450"C;
This promotes adhesion of 90% alumina ceramic substrates. The substrate is then washed with water, immersed in a 10% sulfuric acid solution, and washed again.

The substrate subjected to the accelerated contact is then plated with metal by the method of Example (XV). A uniform, adhesive copper coating is obtained without blisters, voids and skip brating.

Example (XVII) 4 grams of sodium carbonate were ground with 1 gram of potassium nitrate. This dry mixed powder was poured onto a 90% alumina black ceramic substrate (commercially available from NOK Nupark Plug Co., Ltd. as B A-912).

Place the powder-covered substrate in an oven at 700”C.
The powder was melted by heating for 20 minutes.

After cooling, the substrate was washed with water, immersed in a 10% octopus acid solution, and rinsed with water. Next, the adhesion-promoted substrate was used as Example (XVf
) was metal-plated in the same way.

A uniform, adhesive copper level without blisters, voids, and skip brating was obtained.

Example (XVf) An adhesive hybrid circuit pattern of pure copper conductor was applied to a ceramic substrate made of silicon carbide and beryllia by the method of Example [1]. This created a strongly bonded copper circuit pattern on a perilla-rich substrate with excellent thermal conductivity.

EXAMPLE CXTX) The method of Example (I) is repeated except that an electroless nickel plating bath is used in place of the electroless copper plating bath. Electroless nickel plating baths are well known. Electroless nickel plating bath (e 〃〃ηI'l'd Z X , r f3
W.R.I.C.I.A.R.D.S. on Co.

(commercially available as N1klad 'i'94) contains nickel salts, sodium hypophosphite, am7nium hydroxide, and has a pT-1 (measured at 25°C) of 4°5 to
5.2 and is operated at 90”C.”j! (After immersion in the electrolytic nickel plating bath for 30 minutes, the ceramic substrate is removed. It is completely coated without skip brating by a uniform and adhesive nickel coat of lO micrometers thick.

Adhesion of a ceramic substrate (alumina 96%) was promoted by the method of Example [■]. It was given a conductive border by applying silver paint to the edges. 1) Immerse the substrate in the aqueous regulator solution of Example (, IX) for 5 minutes.
Washing with water: 3) Immersion in the halide pre-soaking solution of Example [V] for 5 minutes; 4) Immersion in the catalyst solution of Example (V) at 40"C.
Soak for 10 minutes in: 5 ml of water; 6) Soak for 5 seconds in an aqueous solution of 3.5% fluoroboric acid and 04% hydroxyethyl/leethylene dinitrilotriacetic acid; B7) 75 g/β copper sulfate, ]90 g / (l sulfuric acid, 50mg/β chloride ion and 19/l Pluronic F-1
27 (a polyoxyethylene, polyoxypropylene block copolymer commercially available from BASF-Wyandotte Corp.) with copper in an aqueous solution.

The current density was 0,35 ynh/++u+''.

EXAMPLE [HI] A ceramic lid made to fit over the opening of a hybrid circuit package was adhesion promoted using the method of Example (1).

The ceramic lid was then metal plated with copper in the following manner: a) Chloride presoak containing 3.87 mol of sodium chloride, 0.91 mol of hydrochloric acid, and 11 parts of 0.025 mol of sodium chloride. Immerse in an aqueous solution for 2 minutes at room temperature.

b) Immersion for 15 minutes in the chloride-rich catalyst solution of Example (IV).

C) Wash with water.

d) Immersion in the accelerator solution of Example (IV).

C) Wash with water.

f) Plating copper from the electroless copper plating solution of Example (V).

g) Rinse and dry.

The metal-plated ceramic lid is replaced with the conventional fluoroboric acid lid.
Electroplated with tin-lead (solder) alloy from lead electroplating solution. The lead-lead alloy had a eutectic composition.

The electroplated solder was reflowed by heat.

A metal plated ceramic lid was placed on top of the hybrid circuit package opening to close the package.

The area around the opening had a full metal plating layer covered with solder.

A weight was applied to the top of the ceramic lid.

The metal-plated ceramic lid is hermetically sealed to the hybrid circuit package by passing the package and lid under a nitrogen atmosphere through a belt furnace maintained at 20°C, which is higher than the eutectic point of the solder alloy. Ta. The assembly was cooled to room temperature and the weight was removed.

When testing the seal with the lid of a hybrid circuit package,
It was a hermetic seal defined in MIL-8TD-ss3.

Patent Applicant: Kollmorgen Technologies Corporation Agent: Kenbu Arata (1 other person) Written by Kofu Ko IE (2) August 3, 1980 Director General of the Patent Office 2. Name of Invention: Metallization of Ceramic 3.? IIi Relationship with the case of the person making the correction Patent applicant name Kollmorgen Technologies Corporation 4, Agent 5, Date of amendment order (= 1 Voluntary amendment 6, Number of inventions increased by amendment 7, Subject of amendment Full text of the specification 7・−・ −゛

Claims (1)

[Claims] (1) The surface is treated to adhesively accept all the metal,
A method for metallizing a ceramic substrate comprising depositing metal on the treated surface, the surface being treated with a melt consisting of one or more alkali metal compounds; in a later step, chloride ○ per liter of one or more halides selected from the group consisting of , bromide and iodide. 5 molar dihalides or more and in an amount sufficient to promote the adsorption of soot to the surface and to eliminate bare spots in the bonded metal layer that have formed on the surface or selected portions of the surface. exposing the surface to an acidic halide solution containing the solution, either as a component of a solution used in a catalytic process to render the surface receptive to metal deposition, or immediately followed by the solution; exposing the surface used in a pretreatment step and so treated, or selected portions of the surface, to a metal deposition bath solution to form a uniform metal layer over the surface or selected portions of the surface; A method for fully bending a ceramic substrate, characterized in that: (2) The alkali metal compound is a hydroxide, a carbonate,
A method according to claim 1, wherein the salt is selected from nitrates and hydrogen sulfates and mixtures thereof. (3) The method of claim (1), wherein the melt further contains one or more substances that lower the melting point of the alkali metal compound. (4) The above melt is A%'j of an alkali metal compound! The method of claim 1, wherein the alkali metal compound is a J:A acid salt. and nitrates and mixtures thereof. (6) The acidic halide solution is selected from hydrochloric acid, hydrobromic acid and acidic alkali metal halide solutions, and the alkali metal The method according to claim (1), wherein the halide is selected from sodium and potassium and the halide is selected from bromide, chloride and iodide. (7) The acidic halide i@ solution further contains stannous chloride. (8) The acidic halide solution contains stannous chloride, and the sensitizer is added to the solution before treating the surface with a seeding solution selected from noble metal containing solutions. Claim No. 1 (1) used as a solution
) Method described in section (9) Acidic halide solution is chlorinated! (11) and a mixture obtained from the reaction of a noble metal halide to form a compound suitable for rendering a surface amenable to electroless plating of metals. (101) After treating the surface with an acidic halide solution selected from chlorides, bromides and iodides, the entire surface is further treated with a silver nitrate solution to make it acceptable for electroless plating of metal. The method described in section 1). (11) After treating the surface with an acidic halide solution selected from chloride, bromide, and iodide, the halogen (1-silver) is reduced to metal with light or a reducing agent. Claim No. (1) further comprising treating the surface with a silver nitrate solution.
The method described in section. 02) The first metal layer is formed electrolessly, and the layer is further plated with one or more metals using electroless plating or electroplating methods.
The method described in section 1). (13) The method according to claim (1), wherein the alkali metal compound is heated to 150°C or higher. The method according to claim 1, wherein the alkali metal compound is heated to a temperature of 300"C or higher. t15) The method according to claim 1, wherein the alkali metal compound is heated to 600°C or higher. (I6) The acid halide solution is used as a pretreatment step before the catalytic process, and the ceramic substrate proceeds from the pretreatment process to the catalytic process without rinsing.
The method described in section 1). u7) a) Treat the ceramic surface with a molten alkali metal compound to promote surface adhesion and deep etching; . having a halide concentration of 5 mol/l, sufficient to erase bare spots in the adhesive metal layer formed on the surface or selected portions of the surface;
treating the surface with an acidic halide solution containing one or more halides selected from the group consisting of chloride, bromide and iodide, the acidic halide solution being selected from chloride, bromide and iodide; c) treating a ceramic surface exposed to an acidic halide solution with a catalyst for non-electrometallic (-1) deposition; d) depositing metal 4 on the catalyzed surface; - J put on; e) (9
A method for making a printed circuit on a ceramic substrate, characterized by removing the adhered metal parts and making a metal printed circuit (L) conductor pattern adhered to the surface of the ceramic substrate. 08) The method of claim 11'0, wherein the acidic halide solution contains a catalyst. (191 Catalyticize with a catalyst for electroless metal plating @
The method according to claim t17), wherein the substrate is exposed to an acidic halide solution. (20) The method according to claim 09), wherein the substrate is transferred from the acidic halide solution to the catalyst solution without rinsing. The method according to claim u7, wherein the 2υ metal is deposited by electroplating. (2z+) The method according to claim 07, in which the deposited metal portion is removed by etching. 3) The printed circuit includes a plated hole with a fully plated wall. The method according to claim t17). (2aa) Exposing the surface to a molten alkali metal compound to roughen or promote adhesion. l)) on the adhesion 1 formed on selected parts of the surface in an amount sufficient to erase any bare spots in the metal layer and to promote adsorption of the catalyst for electroless metal plating. C) exposing the surface to an acidic/halogenide solution containing one or more halides, the halides being selected from chlorides, bromides and iodides; C) forming a reservoir for non-electrometal deposition; d) catalyzing the exposed surface with a catalyst; d) non-electrically depositing metal on the portions of the catalyzed surface not printed with resist, thus depositing adhesive metal printed circuit conductors on the substrate; A method for making a printed circuit on a ceramic substrate, characterized by: c! 5) contacting the surface of the substrate with a solution consisting of an alkali metal compound for a sufficient period of time to etch the surface; rinsing the surface with an aqueous solution; neutralizing the surface with an acid and removing the enemy. Repeating the rinsing step; contacting the surface with an acidic halide solution containing one to eight or more halides, the halides being from the group consisting of chlorides, bromides, and iodides. The selected solution facilitates adsorption of the chlorinated sensitizer, erases bare spots in the adhesive metal layer formed on the surface or selected portions of the surface, and containing sufficient halide ions to give a pl-1 of less than about 2; in the presence of the acidic halide solution, the surface is exposed to a sensitizer solution that provides secondary ions and a seeding solution that provides noble metal ions; contacting the surface such that the surface is receptive to electroless plating of a metal, and contacting the surface or selected portions of the surface with a metal plating solution for a sufficient period of time to form a metal layer thereon. ; A method for making a metal-plated conductor pattern on a ceramic substrate, characterized by: (2G) A method according to claim 2, in which the surface is contacted with an acidic halide solution and then, without intermediate rinsing, with a sensitizer solution. The ceramic surface of the ceramic substrate is treated with a melt containing a metal compound, and in a later stage one or more halides selected from the group consisting of chloride, bromide and iodide are added to the surface by 0.5
an amount sufficient to promote adsorption of the catalyst to the surface and to eliminate bare spots in the adhesive metal layer that forms on the surface or selected portions of the surface. A ceramic article comprising a ceramic substrate having a uniform coating of metal formed by exposing the surface to an acidic halide solution comprising: (28) The ceramic article according to claim 127, wherein the metal coating is partially removed to form a metal conductor pattern, and electronic components consisting of semiconductors, resistors, and capacitors are connected thereto. A process for metal plating of ceramic substrates that involves treating a surface to adhesively accept a metal and depositing the metal on the treated surface. treating the surface with; 0,5 mole of a halide selected from the group of chlorides, bromides or iodides which provides the surface with a conductive connector area for cathodic connection in subsequent electroplating; 1//l
Facilitates the adsorption of metal ions selected from groups Ib and Vlll of the Periodic Table of the Elements and eliminates bare spots in the adhesive metal layer that forms on the surface or on selected parts of the surface. Expose the surface to a solution of acid 11 and halogenide in an amount sufficient to erase the surface. Treating the surface with a solution containing a metal selected from Group II) and Group V of the Periodic Table of the Elements and placing metal seats on the surface; Connecting the connector area to the cathode of a power source; contacting a surface with a solution in a pot for electroplating a second metal, contacting the anode of a power source with the solution, and electroplating a second metal on the surface onto the surface or selected portions of the surface; A method for metal plating a ceramic substrate, characterized in that a complete layer of the second metal is formed. (30) consisting of a ceramic material having at least one surface provided with a blank coating of metal adhesively bonded;
The metal forms a hermetic seal at the surface of the ceramic substrate and at its interface, and the coating of the metal blank is prepared by treating the ceramic surface with a melt of one or more alkali metal compounds and, at a later stage, One or more halides selected from chloride, bromide or iodide.
5 mol/4 halide, sufficient to promote adsorption of the catalyst to the surface and to eliminate bare spots in the adhesive metal layer that forms on the surface or on selected portions of the surface. exposing the surface to an acidic halide solution containing a
by adsorbing the catalyst on the surface; and by metallurgically bonding the upper layer that provides a honey-seal at the interface with the ceramic substrate. 31. The method of claim 30, further comprising a metal or metal-plated ceramic top layer bonded to the metallization. (321) treating at least a portion of the surface of the first ceramic article with a melt consisting of one or more alkali metal compounds; If you have more than 0.5-e halides,
/l//l in an acidic halide solution containing in an amount sufficient to promote adsorption of the catalyst onto the surface and to eliminate bare spots in the adhesive metal layer formed on parts of the surface. adsorbing a catalyst onto the treated surface of the first ceramic article and depositing a metal coating on the treated surface in a metal deposition bath; bonding the coated portion to a metal plated portion of a second ceramic article or to a metal article; How to combine.