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Method of Producing Printed Circuits by the Additive Process

IP.com Disclosure Number: IPCOM000041659D
Original Publication Date: 1984-Feb-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Schneider, J: AUTHOR [+2]

Abstract

A method is described which, in addition to generating a thin copper layer on prepregs, provides the walls of the throughholes with a perfect copper coating. By means of a numerically controlled tool, the epoxy resin prepregs are provided with throughholes, through which the X- and Y-planes of printed circuits are later conductively connected by copper plating. The throughholes are cleaned in a plasma process, while the epoxy resin surface is roughened. By means of magnetron DC sputtering, the epoxy resin surface and the walls of the throughholes are then coated with a thin adhesive copper layer. For this purpose, the circuit boards move in a vacuum perpendicular between two cathodes and are simultaneously sputtered with copper on both sides.

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Method of Producing Printed Circuits by the Additive Process

A method is described which, in addition to generating a thin copper layer on prepregs, provides the walls of the throughholes with a perfect copper coating. By means of a numerically controlled tool, the epoxy resin prepregs are provided with throughholes, through which the X- and Y-planes of printed circuits are later conductively connected by copper plating. The throughholes are cleaned in a plasma process, while the epoxy resin surface is roughened. By means of magnetron DC sputtering, the epoxy resin surface and the walls of the throughholes are then coated with a thin adhesive copper layer. For this purpose, the circuit boards move in a vacuum perpendicular between two cathodes and are simultaneously sputtered with copper on both sides. The printed circuit is subsequently generated by known methods on both sides of the epoxy resin prepreg. The described method replaces the expensive wet process for activation of the walls of the throughholes by means of palladium tin chloride as a seeder.

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