| 摘要 |
PROBLEM TO BE SOLVED: To reduce flaking of a solder ball at a reinforcement pad, even if mechanical stress is applied. SOLUTION: In the semiconductor device, a reinforcement pad is formed at each corner of a substrate mounting face in a main base in CSP structure, and a plurality of solder balls are provided on each reinforcement pad. The rectangular reinforcement pad 21 or a triangular reinforcement pad 22 has a mounting part for the solder ball 12 on the outer sides. At lest the mounting part is chamfered to be round, along the outer side of a prescribed region in contact with the main CSP part of the solder ball 12. Mechanical stresses will not be concentrated at the chamfered mounting part to generate acute angles. As a result, flaking of the solder ball 12 can be reduced. |
