| 摘要 |
PROBLEM TO BE SOLVED: To prevent the generation of solder cracks, to prevent its development and disconnection of wire between connection pads due to the change of temperature after the wiring board, having great difference in thermal expansion coefficient, are BGA connected. SOLUTION: Each connection pad 3 is divided by a non-solder wetting material 4, and a plurality of solder wetting surfaces 3a and 3a are provided. When solder ball 6 is soldered on the solder wetting parts 3a and 3a, solder 5 is repelled by the non-solder wetting material 4, and the solder 5 is soldered astriding the solder wetting surfaces 3a and 3a. When BGA junction is formed, the solder 5 maintains a void G the solder wetting surface 4 and the solder 5 astrides each split surface 3a. The thermal stress caused by temperature change is despersed to each split surface 3a, and cracks are hardly generated fundamentally, and even when cracks K are generated on the solder 5 and they develop to the split surface 3a, they stop at the void 5 of the non-solder wetting material 4. The split surface 3a remaining on the opposite side is firmly connected, and disconnection of wire can be prevented. |
