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Lift-Off Process for Metallizing Multilayer Ceramic Substrates Using Alumina-Based Paste As a Resist

IP.com Disclosure Number: IPCOM000038801D
Original Publication Date: 1987-Mar-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Lamelas, FJ: AUTHOR

Abstract

This invention discloses a method and materials for forming stencils of circuit patterns, on ceramic substrates, capable of withstanding metal deposition at temperatures higher than normally tolerated by common, polymeric resist materials. The stencil is written by a laser beam into a deposited layer of a paste or slurry consisting of a suitable inorganic powder such as alumina, thermally depolymerizable binders such as polyvinyl butaryl, polymethyl methacrylate, etc., and volatile solvents commonly used in preparing such slurries or pastes. Typically such slurries or pastes will be composed of 60-70% by weight of the inorganic powder (e.g., alumina), 5-10% by weight of the polymeric binder (e.g., polymethyl methacrylate), with the solvent (e.g., amyl acetate) making up the remainder.

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Lift-Off Process for Metallizing Multilayer Ceramic Substrates Using Alumina-Based Paste As a Resist

This invention discloses a method and materials for forming stencils of circuit patterns, on ceramic substrates, capable of withstanding metal deposition at temperatures higher than normally tolerated by common, polymeric resist materials. The stencil is written by a laser beam into a deposited layer of a paste or slurry consisting of a suitable inorganic powder such as alumina, thermally depolymerizable binders such as polyvinyl butaryl, polymethyl methacrylate, etc., and volatile solvents commonly used in preparing such slurries or pastes. Typically such slurries or pastes will be composed of 60-70% by weight of the inorganic powder (e.g., alumina), 5-10% by weight of the polymeric binder (e.g., polymethyl methacrylate), with the solvent (e.g., amyl acetate) making up the remainder. The steps involved in forming the stencil are as follows: 1. The substrate surface 1 is coated with .002-.005 cm thick layer of paste 2 by spraying, screening or spin coating techniques, as shown in Fig. 1.

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2. The coating is dried in an oven at a temperature of 75-80oC to drive off the volatile solvents, leaving behind a monolithic coating consisting of alumina particles held together by the binder. 3. A programmable laser beam device, equipped with a laser that can impart sufficient heating to the coating to completely depolymerize and thereby volatilize the binder at the point of its incidence, is used to write the desired circuit pattern 3 into coating, as shown in Fig. 2. This step is similar to the pho...