Screenable paste for use as a barrier layer on a substrate during maskless cladding
April 24, 2006. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3726002 Method for making multilayer devices using only a single critical masking step Firing process for forming a multilayer glass-metal module Multilayered glass-ceramic substrate for mounting of semiconductor device Maskless coating of metallurgical features of a dielectric substrate Selective coating of metallurgical features of a dielectric substrate with diverse metals Metallization of a ceramic substrate Diffusion isolation layer for maskless cladding process Patent #: 4582722 InventorsApplicationNo. 06/855263 filed on 04/24/1986US Classes:427/560, Sonic or ultrasonic (e.g., cleaning or removing material from substrate, etc.)106/316, Miscellaneous204/192.15, Specified deposition material or use204/192.17, Electrical contact material216/18, Filling or coating of groove or through hole with a conductor to form an electrical interconnection216/52, MECHANICALLY SHAPING, DEFORMING, OR ABRADING OF SUBSTRATE257/E23.075, Conductive materials containing organic materials or pastes, e.g., for thick films (EPO)29/846, Manufacturing circuit on or in base427/259, Including a masking coating427/264, Deforming the base or coating or removing a portion of the coating427/266, Glass or ceramic base427/97.5, Polymer deposited427/98.5With pretreatment of substrateExaminersPrimary: Powell, William A.Attorney, Agent or FirmInternational ClassesH05K 3/04 (20060101)H05K 3/02 (20060101) H01L 23/48 (20060101) H01L 21/02 (20060101) H01L 21/48 (20060101) H01L 23/498 (20060101) H05K 3/14 (20060101) AbstractDisclosed is a screening paste for covering a selected portion of a metallurgical pattern on a substrate while leaving other metallurgy uncovered. The paste is free of polymers and consists, in one example, of 75-80% of a ceramic particulate (such as alumina), 2-8% amorphous fumed silica and 15-20% of linear alcohol. The linear alcohol serves as a vehicle to deliver the solid particles in the paste. In use, after covering the selected portion of the metallurgical pattern with the paste, the alcohol content therein is expelled by subjecting to vacuum treatment at room temperature or heating to a low temperature below about 275° C. thereby obtaining an inert, dry and crack-free protective coating. Upon evaporation of a new metal layer onto the substrate and removal of the protective coating and new metal layer from everywhere except the uncovered metallurgy, the metallurgical pattern is selectively coated with the new metal.Other References
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