METALLIZING A SUBSTRATE IN A SELECTIVE PATTERN UTILIZING A NOBLE METAL COLLOID CATALYTIC TO THE METAL TO BE DEPOSITED

• US 3,562,038 A
• Filed: 05/15/1968
• Issued: 02/09/1971
• Est. Priority Date: 05/15/1968
• Status: Expired due to Term

• Current Assignee: Charles R. Shipley Jr, Michael Gulla
• Original Assignee: Charles R. Shipley Jr, Michael Gulla
• Inventors: Shipley, Charles R. Jr., Gulla, Michael
• Application Number:
  US04/729,431
• Time in Patent Office: 1,000 Days
• US Class Current: 216/18
• CPC Class Codes: A43B 13/02 characterised by the material
• CPC Class Codes: C23C 18/1605 by masking
• CPC Class Codes: C23C 18/1608 from pretreatment step, i.e. selective pre-treatment
• CPC Class Codes: C23C 18/285 Sensitising or activating with tin based compound or composition
• CPC Class Codes: C23C 18/30 Activating or accelerating or sensitising with palladium or other noble metal
• CPC Class Codes: H05K 3/184 using masks
• CPC Class Codes: Y10S 428/901 Printed circuit

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.

Claims