Patent ID: 8053351

Claim:
A method of forming at least one bonding structure, comprising: forming a ball at a front end of a wire outside a capillary; vertically moving the ball, the wire, and the capillary downwardly to attach the ball to one side of a first pad; pressing the capillary against a center of the ball to form a preliminary compressed ball and a neck portion extending from the preliminary compressed ball; vertically moving the capillary upwardly to expose the preliminary compressed ball and the neck portion; obliquely moving the capillary downwardly with respect to the neck portion to compress the neck portion toward an edge of the preliminary compressed ball to form a compressed ball, the compressed ball substantially covering an entire surface of the first pad and having a wrinkle on an upper surface thereof; moving the capillary from the first pad to a second pad to extend the wire from the compressed ball; and forming a rear end of the at least one bonding structure by moving the capillary towards the second pad to press the wire against the second pad.