Metallization of ceramics

Claim 2

In a process for metallizing a surface of a ceramic substrate which includes treating the surface to adherently receive metal and depositing metal on the treated surface, the improvement which comprises: treating the surface with a melt comprising one or more alkali metal compounds; exposing said surface, in a later step, to an acidic halide solution containing one or more halides selected from the group consisting of chlorides, bromides and iodides and having an acidity and a halide concentration sufficient to promote adsorption of catalyst on the surface and eliminate bare spots in an adherent metal layer formed on the surface or selected parts thereof, wherein said acidic halide solution is greater than 1.5 molar in halide ion and has an acidity greater than 0.001 molar in hydrogen ion; treating said surface with a catalyst solution for rendering said surface receptive to deposition of metal; and exposing the thus treated surface or selected parts of said surface to a metal depositing bath solution thus forming a uniform metal layer on said surface or selected parts thereof.

Claim 3

The process of claim 1 wherein said acidic halide solution is greater than 3 molar in halide ion.

Claim 4

The process of claim 1 wherein said acidic halide solution has an acidity greater than 0.01 molar in hydrogen ion.

Claim 5

The process of claim 1 wherein said acidic halide solution constitutes part of said catalyst solution used for rendering said surface receptive to deposition of metal and said catalyst solution contains from 1.5 to 6 moles of halide per liter and has an acidity from 0.03 to 6 moles per liter.

Claim 6

The process of claim 4 wherein said catalyst solution contains less than 4 moles of halide per liter.

Claim 7

The process of claim 4 wherein said catalyst solution has an acidity from 0.03 to 4 moles per liter.

Claim 8

A process as defined in claim 1 wherein said alkali metal compound is selected from hydroxides, carbonates, nitrates and hydrogen sulfates and mixtures thereof.

Claim 9

A process as defined in claim 1 wherein said melt further includes one or more materials which depress the melting point of said alkali metal compound(s).

Claim 10

A process as defined in claim 1 wherein said melt further includes up to about 20% by weight of one or more materials which depress the melting point of said alkali metal compound(s).

Claim 11

A process as defined in claim 1 wherein said alkali metal compound is selected from carbonates and nitrates and mixtures thereof.

Claim 12

A process as defined in claim 1 wherein the acidic halide solution is selected from hydrochloric acid, hydrobromic acid, and acidic alkali metal halide solutions, said alkali metal selected from sodium and potassium, and said halide selected from bromide, chloride and iodide.

Claim 13

A process as defined in claim 1 wherein the said acidic halide solution is a solution which further includes stannous chloride.

Claim 14

A process as defined in claim 1 wherein the acidic halide solution comprises stannous chloride and is employed as the sensitizer solution prior to treating the surface with seeding solution selected from noble metal comprising solutions.

Claim 15

A process as defined in claim 4 wherein said acidic halide solution comprises an admixture resulting from reacting tin (II) chloride and a precious metal halide forming a compound suitable for rendering surfaces receptive to electroless depositing of metal.

Claim 16

A process as defined in claim 1 wherein subsequent to treating the surface with the acidic halide solution selected from chlorides, bromides and iodides, it is further treated with a silver nitrate solution to render it receptive to electroless deposition of metal.

Claim 17

A process as defined in claim 1 wherein subsequent to treating the surface with the acidic halide solution selected from chloride, bromides and iodides, it is further treated with a silver nitrate solution forming silver halide which is reduced to metal with light or a reducing agent.

Claim 18

A process as defined in claim 1 wherein a first metal layer is electrolessly formed and said layer is further plated up with one or more metals employing electroless or electroplating methods.

Claim 19

A process as defined in claim 1 wherein the alkali metal compound is heated above 150° C.

Claim 20

A process as defined in claim 1 wherein the alkali metal compound is heated above 300° C.

Claim 21

A process as defined in claim 1 wherein the alkali metal compound is heated above 600° C.

Claim 22

A process as defined in claim 1 wherein the acidic halide solution is used as a pretreatment step before the catalyzing sequence, and the ceramic substrate proceeds from the pretreatment step to the catalyzing sequence without rinsing.

Claim 23

Method of making a printed circuit on a surface of a ceramic substrate comprising: treating the ceramic substrate with a molten alkali metal compound to adhesion promote or etch the surface; exposing the surface to acidic halide solution containing one or more halides selected from the group consisting of chlorides, bromides, and iodides having an acidity and a halide concentration sufficient to eliminate bare spots in an adherent metal layer formed on the surface or selected parts thereof, wherein the acidic halide solution contains at least 1.5 moles of halide per liter; treating the ceramic surface with a catalyst for electroless metal deposition; depositing metal onto the catalyzed surface; and removing portions of the deposited metal to produce a metal printed circuit conductor pattern adhering to the surface of the ceramic substrate.

Claim 24

Method of making a printed circuit on a surface of a ceramic substrate comprising: treating the ceramic substrate with a molten alkali metal compound to adhesion promote or etch the surface; exposing the surface to acidic halide solution containing one or more halides selected from the group consisting of chlorides, bromides, and iodides having an acidity and a halide concentration sufficient to eliminate bare spots in an adherent metal layer formed on the surface or selected parts thereof, wherein the acidic halide solution contains at least 1.5 moles of halide per liter; treating the ceramic surface with a catalyst for electroless metal deposition; depositing metal onto the catalyzed surface; and removing portions of the deposited metal to produce a metal printed circuit conductor pattern adhering to the surface of the ceramic substrate.

Claim 25

Method of claim 22 wherein the acidic halide solution comprises the catalyst and said solution contains from 1.5 to 6 moles of halide per liter and has acidity from 0.03 to 6 moles per liter.

Claim 26

Method of claim 22 wherein the substrate is exposed to the acidic halide solution prior to catalyzing with a catalyst for electroless metal deposition and the acidic halide solution is greater than 2 molar in halide ion and has an acidity greater than 0.001 molar in hydrogen ion.

Claim 27

Method of claim 24 wherein the substrate is transferred from the acidic halide solution to a catalyst solution without rinsing.

Claim 28

Method of claim 22 wherein metal is deposited by electroplating.

Claim 29

Method of claim 22 wherein portions of the deposited metal are removed by etching.

Claim 30

Method of claim 22 wherein the printed circuit comprises plates holes with metal plated walls.

Claim 31

Method of making printed circuit on a surface of a ceramic substrate comprising: exposing the surface to a molten alkali metal compound to roughen or adhesion promote the surface; exposing the surface to an acidic halide solution having an acidity and containing one or more halides in an amount sufficient to eliminate bare spots in an adherent metal layer formed on selected parts of the surface, and sufficient to promote adsorption of a catalyst for electroless metal deposition, the halides selected from chlorides, bromides, and iodides, wherein the acidic halide solution contains at least 1.5 moles of halide per liter; catalyzing the exposed surface with a catalyst for electroless metal deposition; printing a resist outlining a conductor pattern on the catalyzed surface; and electrolessly depositing metal on the part of the catalyzed surface not printed with resist, thus making an adherent metal printed circuit conductor pattern on the substrate.

Claim 32

Method of making printed circuit on a surface of a ceramic substrate comprising: exposing the surface to a molten alkali metal compound to roughen or adhesion promote the surface; exposing the surface to an acidic halide solution having an acidity and containing one or more halides in an amount sufficient to eliminate bare spots in an adherent metal layer formed on selected parts of the surface, and sufficient to promote adsorption of a catalyst for electroless metal deposition, the halides selected from chlorides, bromides, and iodides, wherein the acidic halide solution contains at least 1.5 moles of halide per liter; catalyzing the exposed surface with a catalyst for electroless metal deposition; printing a resist outlining a conductor pattern on the catalyzed surface; and electrolessly depositing metal on the part of the catalyzed surface not printed with resist, thus making an adherent metal printed circuit conductor pattern on the substrate.

Claim 33

A process for producing a metallized conductor pattern on a ceramic substrate comprising: contacting a surface of said substrate with a melt comprised of an alkali metal compound for a time period sufficient to etch said surface; rinsing said surface with an aqueous solution; neutralizing said surface with an acid; repeating said rinsing step; contacting said surface with an acidic halide solution containing one or more halides, the halides being selected from the group consisting of chlorides, bromides and iodides, the solution containing sufficient halide ions to promote adsorption of a stannous chloride sensitizer, eliminate bare spots in an adherent metal layer formed on the surface or selected parts thereof, and provide a pH below about 2 at said surface, wherein said acidic halide solution is greater than 2 molar in halide ion contacting said surface with a sensitizer solution providing stannous tin ions and a seeding solution providing precious metal ions, in the presence of said acidic halide solution, to render said surface receptive to electroless deposition of a metal; and contacting said surface or selected parts thereof with a metal depositing solution for a time period sufficient to form a metal layer thereon.

Claim 34

A process for producing a metallized conductor pattern on a ceramic substrate comprising: contacting a surface of said substrate with a melt comprised of an alkali metal compound for a time period sufficient to etch said surface; rinsing said surface with an aqueous solution; neutralizing said surface with an acid; repeating said rinsing step; contacting said surface with an acidic halide solution containing one or more halides, the halides being selected from the group consisting of chlorides, bromides and iodides, the solution containing sufficient halide ions to promote adsorption of a stannous chloride sensitizer, eliminate bare spots in an adherent metal layer formed on the surface or selected parts thereof, and provide a pH below about 2 at said surface, wherein said acidic halide solution is greater than 2 molar in halide ion contacting said surface with a sensitizer solution providing stannous tin ions and a seeding solution providing precious metal ions, in the presence of said acidic halide solution, to render said surface receptive to electroless deposition of a metal; and contacting said surface or selected parts thereof with a metal depositing solution for a time period sufficient to form a metal layer thereon.

Claim 35

A process defined in claim 30 wherein after contacting the surface with the acidic halide solution, it is contacted with the sensitizer solution without an intermediate rinse.

Claim 36

In a process for metallizing a surface of a ceramic substrate which includes treating the surface to adherently receive a metal, and depositing metal on the treated surface, the improvement which comprises: treating the surface with a melt comprising one or more alkali metal compounds; providing the surface with a conductive connector area for cathodic connection in subsequent electroplating; exposing said surface to an acidic halide solution having an acidity from 0.03 to 6 moles per liter and containing halide selected from the group of chlorides, bromides or iodides in an amount greater than 0.5 moles per liter and sufficient to promote adsorption of metal ions selected from Group Ib and Group VIII of the Periodic Table of Elements and to eliminate bare spots in an adherent metal layer formed on the surface or selected parts thereof; treating said surface with a solution comprising a metal selected from Group Ib and Group VIII of the Periodic Table of Elements to deposit metallic sites on the surface; connecting said connectors area to the cathode pole of a power supply; contacting the surface with a solution for electroplating a second metal the anode of the power supply being in contact with said solution; and electroplating the second metal on the surface to form a complete layer of said second metal on said surface or selected parts thereof.

Claim 37

In a process for metallizing a surface of a ceramic substrate which includes treating the surface to adherently receive a metal, and depositing metal on the treated surface, the improvement which comprises: treating the surface with a melt comprising one or more alkali metal compounds; providing the surface with a conductive connector area for cathodic connection in subsequent electroplating; exposing said surface to an acidic halide solution having an acidity from 0.03 to 6 moles per liter and containing halide selected from the group of chlorides, bromides or iodides in an amount greater than 0.5 moles per liter and sufficient to promote adsorption of metal ions selected from Group Ib and Group VIII of the Periodic Table of Elements and to eliminate bare spots in an adherent metal layer formed on the surface or selected parts thereof; treating said surface with a solution comprising a metal selected from Group Ib and Group VIII of the Periodic Table of Elements to deposit metallic sites on the surface; connecting said connectors area to the cathode pole of a power supply; contacting the surface with a solution for electroplating a second metal the anode of the power supply being in contact with said solution; and electroplating the second metal on the surface to form a complete layer of said second metal on said surface or selected parts thereof.