# US 5,703,341 A · Method for adhesion of metal films to ceramics > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,703,341 A - Document ID: US5703341A - Status: Granted - Kind: A - Application number: 08/443,275 - Filed: 1995-05-17 - Granted: 1997-12-30 - Earliest claimed: 1993-11-23 - Assignees: Lockheed Martin Energy Systems, Inc. - Inventors: Douglas H. Lowndes; Anthony J. Pedraza; Melvin J. DeSilva; Rajagopalan A. Kumar - Web page: https://patentgrep.com/patent/US5703341A ## CPC - B23K 26/34: Laser welding for purposes other than joining - B23K 26/32: taking account of the properties of the material involved - C04B 41/0036: {Laser treatment (working by laser beam B23K26/00)} - C04B 41/80: of only ceramics - H05K 3/381: {by special treatment of the substrate} - B23K 2103/08: Non-ferrous metals or alloys - B23K 2103/12: Copper or alloys thereof - B23K 2103/26: {Alloys of Nickel and Cobalt and Chromium} - B23K 2103/52: {Ceramics} - B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM - C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS ## Abstract Methods for making strongly bonded metal-ceramic materials. The methods include irradiating a portion of the surface of the ceramic material with a pulsed ultraviolet laser having an energy density sufficient to effect activation of the irradiated surface of the ceramic material so that adhesion of metals subsequently deposited onto the irradiated surface is substantially increased. Advantages of the invention include (i) the need for only a small number of laser pulses at relatively low focused energy density, (ii) a smoother substrate surface, (iii) activation of the laser-treated surface which provides a chemical bond between the surface and a metal deposited thereon, (iv) only low temperature annealing is required to produce the strong metal-ceramic bond; (v) the ability to obtain strong adhesion between ceramic materials and oxidation resistant metals; (vi) ability to store the laser treated ceramic materials for later deposition of metals thereon. ## Claims ### Claim 1 A method for improving adhesion between an oxide-based ceramic material and metal deposited thereon comprising: irradiating a metal bonding surface of the oxide-based ceramic material with a laser for a period of time and at an energy density above an energy density required to initiate melting of the irradiated surface of the oxide-based ceramic material in order to decrease the surface roughness of the metal bonding surface; depositing one or more metals on the irradiated surface of the ceramic material; and subsequently heat treating the ceramic material containing the metal at a temperature ranging from about 250.degree. to about 700.degree. C. for a period of time sufficient to increase the adhesion between the metal and the oxide-based ceramic material relative to the adhesion of the metal to the oxide-based ceramic material in the absence of heat treating. ### Claim 2 (depends on 1) The method of claim 1 wherein the laser is a pulsed ultraviolet laser. ### Claim 3 (depends on 1) The method of claim 1 wherein the oxide-based ceramic material is selected from the group consisting of polycrystalline alumina, strontium-titanium oxide, beryllium oxide, iron oxide, chrome oxide and zirconium oxide. ### Claim 4 (depends on 3) The method of claim 3 wherein the oxide-based ceramic material is polycrystalline alumina. ### Claim 5 (depends on 4) The method of claim 4 wherein the energy density is in a range of from about 0.7 to about 1.5 J/cm.sup.2. ### Claim 6 (depends on 1) The method of claim 1 wherein the irradiation is conducted under an oxidizing atmosphere. ### Claim 7 (depends on 6) The method of claim 6 wherein the heat treating step is conducted under an oxidizing atmosphere. ### Claim 8 (depends on 1) The method of claim 1 wherein the heat treating step is conducted under an oxidizing atmosphere. ### Claim 9 (depends on 1) The method of claim 1 wherein the metal has an oxide formation energy of greater than 0. ### Claim 10 (depends on 1) The method of claim 1 wherein the metal is selected from the group consisting of gold, copper and nickel. ### Claim 11 (depends on 1) The method of claim 1 wherein the heat treating step is conducted at a temperature within the range of from about 300.degree. to about 500.degree. C. ### Claim 12 (depends on 11) The method of claim 11 wherein the heating treating step is conducted for a period of time ranging from about 5 minutes to about 60 minutes. ### Claim 13 (depends on 1) An oxide-based ceramic material having a deposit of metal chemically bonded thereto made by the method of claim 1 wherein the metal bonding surface is irradiated with an energy density ranging from about 0.5 to about 1.5 J/cm.sup.2 and the adhesion strength between the metal and ceramic is greater than about 20 MPa. ### Claim 14 A process for adhering metal to a surface of a ceramic material comprising: irradiating at least a portion of the surface of the ceramic material with a pulsed ultraviolet laser at an energy density above an energy density required to initiate melting of the irradiated portion of the ceramic material in order to decrease the surface roughness of the metal bonding surface; and depositing metal on the irradiated portion of the ceramic material. ### Claim 15 (depends on 14) The process of claim 14 wherein the ceramic material is an oxide-based ceramic material. ### Claim 16 (depends on 15) The process of claim 15 wherein the ceramic material is irradiated under an oxidizing atmosphere. ### Claim 17 (depends on 15) The process of claim 15 wherein the oxide-based ceramic material is polycrystalline alumina. ### Claim 18 (depends on 17) The process of claim 17 wherein the energy density is in a range of from about 0.7 to about 1.5 J/cm.sup.2. ### Claim 19 (depends on 15) The process of claim 15 wherein the oxide-based ceramic material is selected from the group consisting of polycrystalline alumina, strontium-titanium oxide, beryllium oxide, iron oxide, chrome oxide and zirconium oxide. ### Claim 20 (depends on 14) The process of claim 14 further comprising the step of heat treating the ceramic material and metal deposit at a temperature and for a period of time sufficient to increase the adhesion between the metal and ceramic material relative to the adhesion of the metal to the ceramic material in the absence of heat treating. ### Claim 21 (depends on 20) The process of claim 20 wherein the heat treating step is conducted under an oxidizing atmosphere. ### Claim 22 (depends on 20) The method of claim 20 wherein the heat treating step is conducted at a temperature within the range of from about 300.degree. to about 500.degree. C. ### Claim 23 (depends on 20) The method of claim 20 wherein the heating treating step is conducted for a period of time ranging from about 5 minutes to about 60 minutes. ### Claim 24 (depends on 20) An oxide-based ceramic material having a deposit of a non-oxide forming metal chemically bonded thereto made by the method of claim 20 wherein the metal bonding surface is irradiated with an energy density ranging from about 0.5 to about 1.5 J/cm.sup.2 and the adhesion strength between the metal and ceramic is greater than about 20 MPa. ### Claim 25 (depends on 14) The process of claim 14 wherein the metal has an oxide formation energy of greater than 0. ### Claim 26 (depends on 14) The process of claim 14 wherein the metal is selected from the group consisting of gold, copper and nickel. ### Claim 27 (depends on 14) An oxide-based ceramic material having a deposit of a non-oxide forming metal chemically bonded thereto made by the method of claim 14 wherein the metal bonding surface is irradiated with an energy density ranging from about 0.5 to about 1.5 J/cm.sup.2 and the adhesion strength between the metal and ceramic is greater than about 20 MPa. ### Claim 28 A method for preparing a surface of an oxide-based ceramic material for deposition of one or more metals thereon comprising irradiating at least a portion of a metal bonding surface of the oxide-based ceramic material wherein the irradiating is conducted with a pulsed ultraviolet laser for a period of time and at an energy density which is sufficient to initiate melting of the irradiated surface in order to decrease the surface roughness of the metal bonding surface and to provide a surface which forms chemical bonds with metal deposited thereon. ### Claim 29 (depends on 28) The method of claim 28 wherein the irradiating is conducted in an oxidizing atmosphere. ### Claim 30 (depends on 29) The method of claim 29 wherein the oxide-based ceramic material is selected from the group consisting of polycrystalline alumina, strontium-titanium oxide, beryllium oxide, iron oxide, chrome oxide and zirconium oxide. ### Claim 31 (depends on 30) The method of claim 30 wherein the irradiating is conducted in an oxidizing atmosphere. ### Claim 32 (depends on 29) The method of claim 29 wherein the oxide-based ceramic material is polycrystalline alumina. ### Claim 33 (depends on 32) The method of claim 32 wherein the irradiating is conducted in an oxidizing atmosphere. ### Claim 34 (depends on 33) The method of claim 33 wherein the laser energy density ranges from about 0.7 to about 1.5 J/cm.sup.2. ### Claim 35 (depends on 28) An oxide-based ceramic material for use in electronics applications made by the process of claim 28 wherein the metal bonding surface is irradiated with an energy density ranging from about 0.5 to about 1.5 J/cm.sup.2 to produce an activated surface which provides an adhesive strength between the surface and a metal subsequently deposited thereon of greater than about 20 MPa.