HIGH-RELIABILITY SUBSTRATE FOR SEMICONDUCTOR

Japanese Patent JP3932343

B2

PROBLEM TO BE SOLVED: To provide a high-reliability substrate for a semiconductor having high heat cycle characteristics suitable as substrates for automobiles and electric trains or the like.
SOLUTION: A bonded body is obtained by contacting a copper plate having a thickness of 0.3 mm as a circuit substrate 3 with both faces of aluminum nitride and an alumina substrate as a ceramic substrate 1 on which an active metal solder paste is applied over the entire faces, by contacting a copper plate for a heat radiation plate 4 having a thickness of 0.25 mm with the opposite side, and by bonding by heating it at 850°C in a vacuum furnace. Next, an etching resist is applied onto the circuit substrate, a circuit pattern is formed by etching with iron chloride solution, unnecessary solder is removed, and two-stepped ends are formed by applying a second resist and by applying the etching with the iron chloride solution. Further, in order to form three-stepped ends, it is similarly applied with a third resist applied with the etching with the iron chloride solution, and a circuit having the ends made of solder at the lowermost step. The obtained circuit substrate having the three-stepped ends shows high heat cycle characteristics of 1,500 cycles or more which can not be obtained in a conventional product.

Masami Sakuraba
Kimura Masami
Junji Nakamura
Masaya Takahara

JP2003401987A

June 20, 2007

December 01, 2003

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DOWA Metal Tech Co., Ltd.

H01L23/12; (IPC1-7): H01L23/12

JP7106757A
JP5051271A
JP64059986A

Kenji Wada

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