Formation of bump

Abstract

Abstract PURPOSE:To obtain a favorably bonding bump by a method wherein a ball is formed at the tip of a wire inserted in a capillary and after the ball is pressed and bonded to the part to be bonded, the wire is cut off just over the ball to make the length of the wire remaining on the ball constant. CONSTITUTION:An electric torch 3 is made to oppose to the tip of a wire 2 consisting of such a material as gold, copper or Al, inserted in a capillary 1, sparks are grown between the electric torch 3 and the wire 2 and a ball 4 is formed at the tip of the wire 2. Then, the capillary 1 is made to descend, the ball 4 is pressed on an electrode pad 6, which is used as the part to be bonded, of a semiconductor element 5 and the ball 4 is fused by ultrasonic heating and is fixed to the pad 6. Then, when the capillary 1 is made to ascend, a pair of cutters 7 come entering into the upper side of the ball 4 and cut the wire just over the ball 4. A bump 12 is formed in such a way that its bonding strength and connecting height can be made constant when an external terminal 14 elongated outside from a synthetic resin film 13 is connected, because the wire 2 is cut by a cutting jig 8.

Inventors

• 👤 Tetsuo Ando
• 👤 安藤　鉄男
• 👤 Koichiro Atsumi
• 👤 幸一郎 渥美

Bibliographic Details