| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent cracks on a solder ball or a wiring board, disconnection of an electric wiring and peeling-off of a land. SOLUTION: A land 16 of a BGA-IC 10 is formed into a double layer structure of a first land 31 and a second land 32. The land 32 is formed of a copper plating coating on a through hole 35 of a solder resist film 17 coating the outer peripheral part of a first land 31 patterned on a base 12 to laminate the land 32 on the land 31. Solder balls 18 are soldered on the land 32 protruded from the film 17. Thus, since the land 31 is reinforced with the film 17, the entire land can be prevented from peeling off. Also, since the electric wiring can be prevented from being exposed between the adjacent lands, insulation- resistance and moisture-resistance can be improved. Further, the concentration of the stress on the solder ball 18 soldered on the land 32 can be prevented, cracks in the solder ball can be prevented.</p> |
