At+t Corp.

At&t Bell Laboratories

Kim L Morton

Donald Dinella

Sudarshan Lal

David A Nicol

John E George

Roy K Durnwirth, Jr

Disclosed is a method for testing solder mask material for suitability with an electroless plating process. The Emix potential of the electroless bath is measured. A test substrate including the mask material is then immersed in an electrolyte, and a constant potential at least equal to the Emix potential is applied to a pair of electrodes also immersed in the electrolyte. The test substrate is then inspected to determine adherence of the mask material.

Method for testing solder mask material

Disclosed is a method of providing solder on selected portions of a printed circuit board. Solder is first electroplated over copper conductor patterns on the board by means of a first photoresist layer. After stripping the first photoresist, a second photoresist layer is laminated over the board and developed to expose selected portions of the solder. The exposed portions are selectively stripped. The copper exposed by the selective stripping is then subjected to a scrubbing while the photoresist protects the remaining solder, and the second photoresist is removed.

Selective solder formation on printed circuit boards

Growing community of inventors

Richmond, VA, United States of America

Kim L Morton