SEMICONDUCTOR DEVICE, AND STRUCTURE AND METHOD FOR MOUNTING SAME

PROBLEM TO BE SOLVED: To mount an LSI with many pins, and to ensure high reliability even if no underfill is applied for reinforcement when a semiconductor device is mounted to a mother board, in a semiconductor wherein high density is established by using a flexible substrate. SOLUTION: An interposer 12 to which an LSI 11 is mounted is a combination of a rigid wiring board 121and a flexible wiring board 122, and the combined section of both wiring boards is an element mounting part to which the LSI 11 is mounted. A section projecting from the element mounting part of the flexible wiring board 122is folded back, and a solder ball 15 is mounted to the folded area. The solder ball 15 is used to mount a semiconductor device 100 to a mother board 16. COPYRIGHT: (C)2007,JPO&INPIT