Browse Prior Art Database

Selective Plating on Closely Spaced Metal Areas

IP.com Disclosure Number: IPCOM000093466D
Original Publication Date: 1967-Oct-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Herbst, A: AUTHOR [+2]

Abstract

Selective plating on closely spaced metal regions, e.g., conductive electrodes composed of silver-palladium, molybdenum-manganese, copper, etc., on electronic modules to prepare the electrodes for dip-soldering and to increase the conductivity of such electrodes can be effected using a specialized aqueous electroless plating bath. Standard plating baths operate at such high plating rates that the deposited metal tends to bridge over the narrow gaps between the electrodes and to deposit on the insulating substrate. The following electroless plating bath is typical of the class of baths which overcomes this problem.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 1

Selective Plating on Closely Spaced Metal Areas

Selective plating on closely spaced metal regions, e.g., conductive electrodes composed of silver-palladium, molybdenum-manganese, copper, etc., on electronic modules to prepare the electrodes for dip-soldering and to increase the conductivity of such electrodes can be effected using a specialized aqueous electroless plating bath. Standard plating baths operate at such high plating rates that the deposited metal tends to bridge over the narrow gaps between the electrodes and to deposit on the insulating substrate. The following electroless plating bath is typical of the class of baths which overcomes this problem. Operative

Preferred Millimols/

Millimols/liter liter

Sodium hypophosphite 140 30-400 NaH(2)PO(2).H(2)O
Nickel chloride 50 10-100 NiCl(2).6H(2)O
Tartrate or citrate 120 30-300 complexing agent
Sufficient ammonia in the aqueous solution to bring the pH to about 9 6-13

The nickel salt in the bath can be replaced completely or in part by an iron or cobalt salt. The hypophosphite can be replaced by dimethylamineborane or other reducing agent. The plating rate at 25 degrees C is about 100 angstroms per minute. The plated electrodes can be readily tinned by dip-soldering.

1