| 摘要 |
PROBLEM TO BE SOLVED: To obtain a printed wiring board capable of obtaining highly reliable electric connection independently of a difference between the thermal expansion coefficients of a PKG and the printed wiring board. SOLUTION: A board 2 is constituted so as to have two board grooves 6, 6 on the tip of a land 3. A ball 5 is arranged on the upper part of the land 3 between these two grooves 6, 6 and the PKG 4 is arranged on the ball 5. The grooves 6, 6 cross a straight line connecting the center of the PKG 4, and the land 3 and the grooves 6, 6 are made non-parallel with the straight line. No groove 6 exists just under the land 3 connected to the PKG (terminal) 4. In the constitution, an influence caused by a difference between the thermal expansion coefficients of the PKG (semiconductor package or a semiconductor chip) and the printed wiring board can be reduced as much as possible, and highly reliable electric connection can be obtained. COPYRIGHT: (C)2005,JPO&NCIPI
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