| 摘要 |
<p>PROBLEM TO BE SOLVED: To improve connection reliability in a connection part between a small semiconductor device and a printed wiring board, which changes owing to an environment, by providing plural non-circular lands which are arranged in a grating form and whose distances from the centers of the lands differ in a vertical direction and a lateral direction. SOLUTION: A small semiconductor device 1 is provided with plural lands 5 which are arranged in a grating form, whose distance from the centers of the lands differ in a vertical direction and a lateral direction and which are formed in different non- circular forms. The non-circular forms are rectangles, ellipses and flat ovals. In the lands 5, longitudinal directions where the distances from the centers of the lands 5 are arranged in a direction where the coefficient of thermal expansion on a carrier 3 constituting the small semiconductor 1 is large. Thus, a solder connection part is made rigid and strength against thermal stress is improved by making solder quality in the direction where the coefficient of thermal expansion is larger to be much. Consequently, the semiconductor device where connection reliability in the connection part between a printed wiring board and the small semiconductor device is improved is installed.</p> |
