US Patent No. 9,661,758

METHODS OF SEGMENTED THROUGH HOLE FORMATION USING DUAL DIAMETER THROUGH HOLE EDGE TRIMMING


Patent No. 9,661,758
Issue Date May 23, 2017
Title Methods Of Segmented Through Hole Formation Using Dual Diameter Through Hole Edge Trimming
Inventorship Douglas Ward Thomas, Pacific Grove, CA (US)
Shinichi Iketani, Sunnyvale, CA (US)
Assignee SANMINA CORPORATION, San Jose, CA (US)

Claim of US Patent No. 9,661,758

1. A method for forming a segmented through hole in a printed circuit board using dual diameter through hole edge trimming,
comprising:
drilling a first hole in the printed circuit board, the first hole having a first diameter;
drilling a second hole within the first hole, the second hole having a second diameter where the second diameter is larger
than the first diameter, and where a ledge is formed at a point between an end of the second hole and the first hole;

applying an electroless copper plating to an inner surface of the first hole and the second hole;
trimming material formed on the ledge of the segmented through hole when applying the copper plating; and
applying an electrolytic copper to the inner surface of the first hole and the second hole.