Process of producing plated through-hole printed circuit boards

Abstract

Abstract PLATED THROUGH-HOLE PRINTED CIRCUIT BOARDS ARE PRODUCED BY PRINTING A FIRST RESIST MATERIAL (I.E. PHOTORESIST) ONTO APPROPRIATE METAL-CLAD LAMINATE BOARD SURFACES IN A PATTERN PREDETERMINED BY THE DESIRED CIRCUITS AND THEN UNIFORMLY COATING ALL OF THE BOARD SURFACES WITH A SECOND RESIST MATERIAL (I.E. A NITROCELLULOSE LACQUER) AND PRODUCING DESIRED THROUGH-HOLES BETWEEN SELECTED AREAS OF THE COATED BOARD SURFACES. THEREAFTER A LAYER OF A FIRST METAL (I.E. CU) IS APPLIED ONTO THE THROUGH-HOLE WALLS AND ON THE COATED SURFACES BY A METAL-REDUCTION PROCESS AND SUCH METAL LAYER IS THEN REMOVED FROM ONLY THE COATED SURFACES AND A LAYER OF A SECOND METAL (I.E. AU) IS ELECTROPLATED ONTO METAL-RECEPTIVE HOLE WALLS AND/OR BOARD SURFACES. THEN THE SECOND RESIST MATERIAL IS REMOVED FROM THE BOARD SURFACES AND THEN PORTIONS OF THE METAL-CLAD ARE REMOVED FROM THE BOARD SURFACES IN A PATTERN PREDETERMINED BY THE DESIRED CIRCUITS. THE ELECTROPLATING CAN OCCUR BEFORE OR AFTER THE REMOVAL OF THE SECOND RESIST MATERIAL; WHEN OCCURRING BEFORE, THE SECOND METAL IS ELECTROPLATED ONLY ON THE COATED THROUGH-HOLE WALLS AND WHEN OCCURRING AFTER, THE SECOND METAL IS ELECTROPLATED ON THE COATED THROUGH-HOLE WALLS AND ON THE METAL-CLAD BOARD SURFACES FREE OF RESIST MATERIAL.

Inventors

• 👤 Hans-Hermann Merkenschlager

Bibliographic Details