Browse Prior Art Database

Multilayer Circuit Board

IP.com Disclosure Number: IPCOM000073503D
Original Publication Date: 1970-Dec-01
Included in the Prior Art Database: 2005-Feb-22
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Canizzaro, JR: AUTHOR [+2]

Abstract

Circuit board 10 comprises laminated layers of conductive material 11, such as copper, and dielectric material 12, such as epoxy glass. Conductive layers 11 have circuit patterns formed therein prior to lamination or may be continuous sheets which serve as voltage or ground planes. The upper and lower parts of board 10 are separated by dielectric layer 13 which is not plated by conductive material 15 within thru-hole 14, i.e. the plating 15 in thru-hole 14 is discontinuous. The preferred material for layer 13 is a polyimide. Other materials which can be used are fluorocarbon, polyethylene, polypropylene, polyphenylene oxide, and polysulfone. An adhesive 16 (e.g. pre-preg) bonds layer 13 to conductive layers 11.

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Multilayer Circuit Board

Circuit board 10 comprises laminated layers of conductive material 11, such as copper, and dielectric material 12, such as epoxy glass. Conductive layers 11 have circuit patterns formed therein prior to lamination or may be continuous sheets which serve as voltage or ground planes. The upper and lower parts of board 10 are separated by dielectric layer 13 which is not plated by conductive material 15 within thru-hole 14, i.e. the plating 15 in thru-hole 14 is discontinuous. The preferred material for layer 13 is a polyimide. Other materials which can be used are fluorocarbon, polyethylene, polypropylene, polyphenylene oxide, and polysulfone. An adhesive 16 (e.g. pre-preg) bonds layer 13 to conductive layers
11.

The method for plating thru-hole 14 with discontinuities in conductive coating 15 where KAPTON* polyimide material is used comprises the steps of initially cleaning hole 14 after drilling with an ammonium persulphate solution and one or more acid rinses to remove grease and other contaminants from the copper and dielectric materials which might inhibit deposition. The epoxy glass and pre-preg of layers 12 and 16 are then sensitized with acid solutions of stannous-chloride and palladium chloride to produce metallic nucleating sites for the electroless deposition of a light layer of copper from a basic copper bath. Conductive layer 15 is then deposited on the light pre-layer by electroplating copper from an acid solution of copper py...