Metallizing a substrate in a selective pattern utilizing a noble metal colloid catalytic to the metal to be deposited

Abstract

Abstract A PROCESS FOR THE DEPOSITION OF ELECTROLESS METAL ON SELECTED AREAS OF A SUBSTRATE USING A COLLOIDAL CATALYST SOLUTION OF A METAL CATALYTIC TO THE ELECTROLESS METAL TO SENSITIZE THE SUBSTRATE. THE CATALYST IS PREFERABLY A NOBLE METALSTANNIC ACID COLLOID AND MOST PREFERABLY A PALLADIUMSTANNIC ACID COLLOID. THE PROCESS TAKES ADVANTAGE OF THE DISCOVERY THAT THE SURFACE OF A SUBSTRATE MAY BE TREATED TO ABSORB AND/OR RETAIN A COLLOIDAL CATALYST TO A GREATER EXTENT THAN AN UNTREATED SURFACE. THE PROCESS, IN ONE OF ITS SIMPLEST EMBODIMENTS, COMPRISES PROVIDING A SUBSTRATE HAVING TREATED AND UNTREATED SURFACE AREAS, SENSITIZING THE SUBSTRATE WITH A COLLOIDAL CATALYST, CONTACTING THE SUBSUBSTRATE WITH A STRIPPER FOR THE ADSORBED COLLOIDAL CATALYST FOR A TIME SUFFICIENT TO STRIP SUBSTANTIALLY ALL OF THE ADSORBED COLLOID FROM THE UNTREATED SURFACE AREAS AND INSUFFICIENT TO STRIP THE ADSORBED COLLOID FROM THE TREATED SURFACES, AND DEPOSITING ELECTROLESS METAL SELECTIVELY OVER THE TREATED AREAS OF THE SUBSTRATE. THE PROCESS IS ESPECIALLY WELL ADAPTED FOR THE FORMATION OF PRINTED CIRCUIT BOARDS AND IS PARTICULARLY USEFUL FOR FORMING CONDUCTIVE THROUGH HOLES BETWEEN SURFACES OF A PRINTED CIRCUIT BOARD.

Inventors

• 👤 Charles R Shipley Jr
• 👤 Michael Gulla

Bibliographic Details