| 摘要 |
PROBLEM TO BE SOLVED: To make hard the generation of the faultiness of the disconnection of an electrode wiring in a BGA type semiconductor device in the case of its mounting, by providing on its electrode a buffer layer made of a high-melting-point solder wherewith the whole of its electrode is covered and whose peripheral edge portion extends to the rear surface of its package board, and by providing a seating layer on the buffer layer. SOLUTION: A BGA type semiconductor device 1 has a rectangular-plate-like package board 2 comprising the structure of a multilayer circuit board the middle of whose top surface is recessed in the form of two stages. An external terminal 11 is formed out of an electrode 15 comprising a wiring formed on the rear surface of the package board 2, a buffer layer 14 made of a high-melting-point solder layer with a predetermined thickness wherewith the whole of the electrode 15 is covered, and a metallic sphere 17 fixed on the buffer layer 14 via a seating layer 16 made of a solder. The electrode 15 is covered completely with the buffer layer 14, and the peripheral edge portion of the buffer layer 14 extends to the package board 2 over a predetermined length. Thereby, the reliability of the mounting structure of the BGA type semiconductor device 1 can be improved and its long life time can be achieved. |
