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:
Jan. 04, 1994
Filed:
Mar. 25, 1991
Ryohei Satoh, Yokohama, JP;
Fumiyuki Kobayashi, Sagamihara, JP;
Yutaka Watanabe, Hadano, JP;
Tositada Netsu, Hadano, JP;
Mitugu Shirai, Hadano, JP;
Kenji Takeda, Kamakura, JP;
Masahide Harada, Fujisawa, JP;
Kiyoshi Matsui, Yokohama, JP;
Hideaki Sasaki, Hadano, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
The present invention provides a multistep electronic circuit device comprising a plurality of parts and elements mechanically or electrically bonded in sequence to each other and to a substrate with a plurality of solders, which comprises as the parts and elements the substrate, input and output pins and LSI chips, and optionally packages and a cooler bonded through multistep bonding, the bondings of the parts and elements including at least one CCB bonding and at least one sealing, the solders each having a lower melting point than the heatproof temperature of the part or element to be bonded with the solder, and one of the solders having a melting point of at least 10.degree. C. lower than that of the other solder used at the bonding step immediately before. The solders used are selected from Au10-15wt%Ge alloy (melting point: 356.degree.-450.degree. C.), Pb1-5wt%Sn alloy (melting point: 314.degree.-325.degree. C.), Pb10-13wt%Sn alloy (melting point: 270.degree.-300.degree. C.), Au20wt%Sn alloy (melting point: 280.degree. C.), Sn3-6wt%Sb alloy (melting point: 232.degree.-243.degree. C.), Sn2-8wt%Ag alloy (melting point: 221.degree.-235.degree. C.), Sn35-55wt%Pb alloy (melting point: 183.degree. -200.degree. C.) and Sn45wt%Pb18wt%Bi (melting point: 135.degree.-160.degree. C.).