Patent ID: 7044357

Claim:
A bump formation method comprising a sequence of: a first step that forms a ball on a tip end of a wire that passes through a capillary and joins said ball to a conductor to form a press-bonded ball; a second step that raises and then moves said capillary in a horizontal direction to a first position so that a flat portion on a lower end of said capillary on a side of said capillary opposite to said horizontal-direction movement is positioned to face said press-bonded ball; a third step that lowers said capillary so that said press-bonded ball is pressed by said flat portion of said capillary to form a first bump; a fourth step that raises and moves said capillary in an opposite horizontal direction from said horizontal-direction movement of said capillary in said second step to a second position so that a flat portion on said lower end of said capillary on a side of said capillary opposite to said opposite horizontal-direction movement is positioned to face said first bump; a fifth step that lowers said capillary so that said wire is bent and pressed against a surface of said first bump by said flat portion of said capillary, thus forming a second bump; and a sixth step that cuts said wire from said second bump.