The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 10, 2015
Filed:
Mar. 03, 2009
Minoru Ueshima, Matsudo, JP;
Masayuki Suzuki, Soka, JP;
Yoshie Yamanaka, Tokyo, JP;
Shunsaku Yoshikawa, Soka, JP;
Tokuro Yamaki, Kobe, JP;
Tsukasa Ohnishi, Koshigaya, JP;
Minoru Ueshima, Matsudo, JP;
Masayuki Suzuki, Soka, JP;
Yoshie Yamanaka, Tokyo, JP;
Shunsaku Yoshikawa, Soka, JP;
Tokuro Yamaki, Kobe, JP;
Tsukasa Ohnishi, Koshigaya, JP;
Senju Metal Industry Co., Ltd., Tokyo, JP;
Abstract
Solder used for flip chip bonding inside a semiconductor package was a Sn—Pb solder such as a Pb-5Sn composition. Lead-free solders which have been studied are hard and easily form intermetallic compounds with Sn, so they were not suitable for a flip chip connection structure inside a semiconductor package, which requires stress relaxation properties. This problem is eliminated by a flip chip connection structure inside a semiconductor package using a lead-free solder which is characterized by consisting essentially of 0.01-0.5 mass percent of Ni and a remainder of Sn. 0.3-0.9 mass percent of Cu and 0.001-0.01 mass percent of P may be added to this solder composition.