Semiconductor device
AssigneeHitachi, Ltd.
InventorsKoji Sasaki, Shinji Hiramitsu, Tadaaki Kariya, Satoshi Matsuyoshi, Ryouichi Kajiwara, Shosaku Ishihara
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Abstract
A semiconductor device is provided, in which buffer layers having a coefficient of linear expansion of 3×10−6/° C. to 8×10−6/° C. are joined to upper and lower surfaces of a silicon chip through a Pb-free solder having a thickness of not more than 0.05 mm and a melting point of not less than 250° C. The upper surface of the upper buffer layer and the lower surface of the lower buffer layer are respectively joined to a lead and a base through Pb-free solders having a thickness of not less than 0.15 mm and a melting point of not less than 250° C.
Claims8
A semiconductor device comprising:
- a silicon chip having a rectifying function;
- an upper, conductive buffer layer having a low coefficient of linear expansion and joined to an upper side of the silicon chip through a Pb-free solder containing no Pb;
- a lower, conductive buffer layer having a low coefficient of linear expansion and joined to a lower side of the silicon chip through a Pb-free solder containing no Pb;
- a conductive lead joined to an upper side of the upper buffer layer through a Pb-free solder containing no Pb;
- and
- a conductive base joined to a lower side of the lower buffer layer through a Pb-free solder containing no Pb,
- wherein the solder on the upper and lower sides of the silicon chip has a thickness of not more than 0.05 mm,
- wherein the solder on the upper side of the upper buffer layer has a thickness of not less than 0.15 mm, and the solder on the lower side of the lower buffer layer has a thickness of not less than 0.15 mm, and wherein the Pb-free solder containing no Pb has a melting point of not less than 250° C.
Dependencies are inferred from the claim text.