Flush printed circuit apparatus

Claim 2

THE PROCESS FOR PRODUCING PLATED THROUGH HOLES IN A FLUSH SURFACE PRINTED CIRCUIT BOARD HAVING CONDUCTIVE PATH THEREON COMPRISING THE STEPS OF: APPLYING AN ELECTROLESS PLATED FLASH TO THE ENTIRE BOARD INCLUDING THE OPENINGS DEFINING THE HOLES; APPLYING AND DEVELOPING A RESIST MATERIAL ON THE BOARD WHEREIN THE AREA IN THE IMMEDIATE VICINITY OF THE HOLES IS LEFT UNPROTECTED; ELECTROPLATING CONDUCTIVE MATERIAL TO THE ELECTROLESS FLASH MATERIAL FOR PLATING THE SURFACE OF THE OPENINGS; REMOVING THE PHOTORESIST AND ANY EXTENSIONS OF THE ELECTROPLATED MATERIAL FROM THE SURFACE OF THE BOARD; REMOVING THE EXPOSED ELECTROLESS FLASH MATERIAL WHEREBY THE SURFACE OF THE BOARD AND THE CONDUCTIVE PATHS REMAIN SUBSTANTIALLY FLUSH; REMOVING CONDUCTIVE MATERIAL FROM THE PATHS AND HOLES OF THE PLATED CIRCUIT BOARD TO A DEPTH BELOW THE SURFACE OF THE BOARD; AND OVERPLATING THE CONDUCTIVE MATERIAL.

Claim 3

A printed circuit board produced in accordance with the steps of: applying and developing a resist material to a double cladded copper flushing type printed circuit board wherein the developed resist material defines conductive paths and patterns on the cladded surfaces; etching the cladded material to leave only the conductive patterns and paths; removing the resist material; applying pressure to recess the conductive paths and patterns flush with the surface openings of the board; applying heat to cure the base material; removing material from the board to define openings extending from conductive material on one surface of the board to conductive material on the other surface of the board; attaching a conductive flashing to the board; applying and developing a resist material to define the areas of the openings in the board wherein it is desired that there be permanent conductive paths from one side of the board to the other; electrically applying further conductive copper material, in the area of the opening, on the exposed flash; removing the remaining resist material; removing the flashing exposed by the removal of the last mentioned resist material; the board being further processed by etching the circuit paths after the removal of the last mentioned resist material below the surface of the board; and attaching an overplating to all exposed copper paths and patterns.

Claim 4

A printed circuit board produced in accordance with the steps of: applying and developing a resist material to a double cladded copper flushing type printed circuit board wherein the developed resist material defines conductive paths and patterns on the cladded surfaces; etching the cladded material to leave only the conductive patterns and paths; removing the resist material; applying pressure to recess the conductive paths and patterns flush with the surface openings of the board; applying heat to cure the base material; removing material from the board to define openings extending from conductive material on one surface of the board to conductive material on the other surface of the board; attaching a conductive flashing to the board; applying and developing a resist material to define the areas of the openings in the board wherein it is desired that there be permanent conductive paths from one side of the board to the other; electrically applying further conductive copper material, in the area of the opening, on the exposed flash; removing the remaining resist material; removing the flashing exposed by the removal of the last mentioned resist material; the board being further processed by etching the circuit paths after the removal of the last mentioned resist material below the surface of the board; and attaching an overplating to all exposed copper paths and patterns.