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Method of Protecting Circuit Lines by Tampon Printing

IP.com Disclosure Number: IPCOM000102371D
Original Publication Date: 1990-Nov-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 46K

Publishing Venue

IBM

Related People

Daley, LR: AUTHOR [+2]

Abstract

Disclosed is a method of protecting electroplated copper lines from an etchant by applying a polymeric resist to the tops of the lines after the photoresist is stripped, but before the electroless copper is etched.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 70% of the total text.

Method of Protecting Circuit Lines by Tampon Printing

       Disclosed is a method of protecting electroplated copper
lines from an etchant by applying a polymeric resist to the tops of
the lines after the photoresist is stripped, but before the
electroless copper is etched.

      The manufacture of circuit cards by the semi-additive process
normally involves the steps of:  (1) flash plating electroless copper
on the card; (2) applying, exposing and developing a photoresist to
leave bare copper in the line areas; (3) electroplating the bare
copper to the thickness of the resist; (4) tinning the copper lines;
(5) stripping the resist; (6) flash etching the electroless copper;
and (7) stripping the tin from the lines.  When used on injection
molded cards, the process of stripping the tin from the lines damages
the bond between the lines and the polyetherimide card material.  Not
applying tin causes the line thickness to be reduced when the flash
copper is etched.

      This method gives protection to the electroplated copper lines
by applying a polymeric resist to the tops of the lines after the
photoresist is stripped, but before the electroless copper is etched.
This avoids the problem of reducing adhesion of the lines to the
card, while solving the problem of protecting the lines from etching.

      The method is as follows:  (1) flash plating electroless copper
on the card; (2) applying resist by the tampon (or pad) printing
process, in which resis...