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Method for Printed Circuit Plating

IP.com Disclosure Number: IPCOM000092334D
Original Publication Date: 1967-Dec-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Rahemba, FJ: AUTHOR

Abstract

The method is for adding additional plating to closely spaced printed circuit lines. The method comprises placing a filler material 11, such as asphaltum, over the selected area of the printed circuit 12 where further plating is to be added to the circuit lines. Material 11 must be sufficiently liquid to completely fill the small spaces between the printed circuit lines which in most cases are obtained by the known etching process.

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Method for Printed Circuit Plating

The method is for adding additional plating to closely spaced printed circuit lines. The method comprises placing a filler material 11, such as asphaltum, over the selected area of the printed circuit 12 where further plating is to be added to the circuit lines.

Material 11 must be sufficiently liquid to completely fill the small spaces between the printed circuit lines which in most cases are obtained by the known etching process.

Material 11 is then dried to its solid state. In the case of asphaltum, the drying is done at 150 degrees F for five minutes. Circuits 12 are then thoroughly cleaned by removing the filler material and the KPR* left from the etching of the circuits. This can most easily be accomplished by scraping with a scalpel blade and then polishing the circuit line surfaces with, e.g., steel wool. The area is then thoroughly rinsed. The area, in which the circuit lines to be plated are located, is then placed in a electroplating bath where the electroplating takes place.

This results in a smooth surface plating on the circuit lines which has a uniform wall buildup without any bridging, migration or other shorting deposits between the lines. One electroplating bath consists of a copper pyrophosphate bath which is maintained at a temperature of 120 degrees F for three hours while the electroplating takes place. The method can use various types of fillers and plating baths. The particular choice depends on the parti...