| 摘要 |
PROBLEM TO BE SOLVED: To accomplish a highly reliable semiconductor device on which the fatigue life of a solder bump can be extended. SOLUTION: The diameter of the area equal to the area of the part, which comes in contact with the pad 9 or the pad 10 of a lead-free solder bump 7, is set as A size and the diameter of the sphere of the cubic volume equal to the cubic volume of the lead-free solder bump 7 is set as B size. In this case, when the A size of the solder bump 7 is formed in the size which is 0.8 to 1.1 times of the B size, the contact surface of the solder bump 7 and the pads 9 and 10 is increased, and the intensity of junction interface is increased. Also, in proportion to the A-size becoming larger, it becomes cylindrical shape, the regidity of the solder bump 7 itself becomes higher, and the amount of thermal deformation added to the solder bump 7 becomes small.
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