Fishing – trapping – and vermin destroying
Patent
1989-10-24
1992-02-11
Chaudhuri, Olik
Fishing, trapping, and vermin destroying
437210, 437220, 148DIG17, 361421, 428620, H01L 2160
Patent
active
050875906
ABSTRACT:
With a method of and an apparatus for manufacturing semiconductor devices using copper-type lead frames with no silver plating, semiconductor devices are continuously manufactured in the following steps: first, a semiconductor pellet having electrodes on its surface is bonded, through a resin material, to a die pad on a copper-alloy lead frame which is not silver-plated. The resin material used for the bonding is then cured by heating it for 120 seconds or less in a non-oxidizing-gas atmosphere having an oxygen density of 1000 ppm or less. Then, the thickness of the oxide film which is formed on the surface of the lead frame while curing the resin material is reduced to 20 .ANG. or less by keeping the lead frame in a deoxidizing-gas atmosphere having an oxygen density of 500 ppm or less. Afterwards, wire-bonding is effected between the electrodes of the semiconductor pellet and the inner leads of the lead frame in 12 seconds or less in a deoxidizing-gas atmosphere while keeping the oxygen density around the surface of the lead frame at 3000 ppm or less.
REFERENCES:
patent: 4732733 (1988-03-01), Sakamoto et al.
patent: 4894752 (1990-01-01), Muraya et al.
"VLSI & GaAs Chip Packaging Workshop", Sep. 12-14, 1988, p. 8.
Fujimoto Hitoshi
Masuda Hisao
Osaka Shuichi
Uwagawa Noriaki
Chaudhuri Olik
Griffis Andrew
Mitsubishi Denki & Kabushiki Kaisha
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