Patent ID: 6193134
Filing Date: 2001-02-27
Classification: B23K

Abstract:
A method for determining quality of bonding between a conductive ball comprised of a first conductive material and a conductive pad comprised of a second conductive material, said conductive ball being bonded to said conductive pad by formation of an intermediary material formed from said first conductive material of said conductive ball and said second conductive material of said conductive pad, the method including the steps of:A. etching said intermediary material between said conductive ball and said conductive pad such that said conductive ball is decoupled from said conductive pad, said conductive ball having a first color in areas where said intermediary material was not abutting said conductive ball and having a second color in areas where said intermediary material was abutting said conductive ball when said conductive ball was bonded to said conductive pad;and wherein said intermediary material was abutting an intermediary material area of said conductive ball when said conductive ball was bonded to said conductive pad;B. capturing a magnified image of said intermediary material area on said conductive ball with said intermediary material area being substantially centered within said magnified image while said conductive ball is decoupled from said conductive pad;and wherein said intermediary material area appears as said second color within said magnified image and wherein an area of said conductive ball wherein said intermediary material was not abutting said conductive ball appears as said first color within said magnified image; andC. analyzing said magnified image of said intermediary material area on said conductive ball to determine quality of bonding between said conductive ball and said conductive pad.