| 摘要 |
PROBLEM TO BE SOLVED: To raise the temperature resistance cycle property by reinforcing the strength of a board. SOLUTION: This device 1 is composed of a circuit pattern and a solder ball mounting lands 3, 3,... which are made on a board, and a solder ball mounting land 5 of normal size which is made in larger area than a normal size of land 3 for mounting solder ball, in a region 4 where a semiconductor integrated circuit chip is mounted, at the center of the board 2. The solder ball mounting land 5 is made in such area as to include the four places of the solder ball mounting land 3 having a normal size. This device 1 is secondarily mounted on a mother board, and it can withstand the stress by temperature cycle enough since it is reinforced by the solder ball mounting land 5 even if it is subjected to the repeated stress of expansion and contraction by heat.
|
