US5087590A
Expired / Lapsed
US
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Method of manufacturing semiconductor devices
Assignee: Mitsubishi Electric Corp
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Filing: 1989-10-24
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Granted: 1992-02-11
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Expires: 2009-10-24
Abstract
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 Å 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.
Inventors
- 👤 Hitoshi Fujimoto
- 👤 Hisao Masuda
- 👤 Shuichi Osaka
- 👤 Noriaki Uwagawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:51
CPC Classifications
H; H10; H10W; H10W70/00; H10W70/01; H10W70/04; H10W70/041; H10W72/00; H10W72/071; H10W72/073; H10P; H10P72/00; H10P72/04; H10P72/0431; H10P72/0438; H10W70/40; H10W70/411; H10W70/417; H10W70/456; H10W70/457; H10W72/0711; H10W72/07141; H10W72/075; H10W72/07541; H10W72/30; H10W72/351; H10W72/353; H10W72/354; H10W72/50; H10W72/531; H10W72/536; H10W72/5363; H10W72/541; H10W72/5449; H10W72/551; H10W72/552; H10W72/5522; H10W72/59; H10W72/851; H10W72/874; H10W72/884; H10W72/90; H10W72/951; H10W72/952; H10W74/00; H10W90/00; H10W90/701; H10W90/731; H10W90/736; H10W90/751; H10W90/756; Y; Y10; Y10S; Y10S148/00; Y10S148/017; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49117; Y10T29/49121; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12528
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
164 words
A method of manufacturing semiconductor devices comprising: bonding a semiconductor pellet having electrodes to a die pad of an unplated copper-alloy lead frame with a resin; curing said resin by heating said lead frame, resin, and semiconductor pellet in a non-oxidizing atmosphere having an oxygen concentration of no more than 1000 ppm; reducing the thickness of an oxide film formed on the surface of said lead frame during the curing of said resin in a deoxidizing atmosphere having an oxygen concentration of no more than 500 ppm; transferring said lead frame with the reduced thickness oxide film to a deoxidizing atmosphere having an oxygen concentration at the surface of said lead frame of no more than 3000 ppm; and wire-bonding wires between said electrodes of said semiconductor pellet and leads of said lead frame within 12 seconds of transfer of said lead frame to the deoxidizing atmosphere having an oxygen concentration at the surface of said lead frame of no more than 3000 ppm.
Claim 2
Independent Claim
164 words
A method of manufacturing semiconductor devices comprising: bonding a semiconductor pellet having electrodes to a die pad of an unplated copper-alloy lead frame with a resin; curing said resin by heating said lead frame, resin, and semiconductor pellet in a non-oxidizing atmosphere having an oxygen concentration of no more than 1000 ppm; reducing the thickness of an oxide film formed on the surface of said lead frame during the curing of said resin in a deoxidizing atmosphere having an oxygen concentration of no more than 500 ppm; transferring said lead frame with the reduced thickness oxide film to a deoxidizing atmosphere having an oxygen concentration at the surface of said lead frame of no more than 3000 ppm; and wire-bonding wires between said electrodes of said semiconductor pellet and leads of said lead frame within 12 seconds of transfer of said lead frame to the deoxidizing atmosphere having an oxygen concentration at the surface of said lead frame of no more than 3000 ppm.
Claim 3
Dependent Claim
13 words
A method as claimed in claim 1 wherein said non-oxidizing gas is nitrogen.
Claim 4
Dependent Claim
18 words
A method as claimed in claim 1 wherein said deoxidizing gas is a mixture of hydrogen and nitrogen.
Claim 5
Dependent Claim
34 words
A method as claimed in claim 1 including limiting the thickness of the oxide film on the surface of said lead frame during curing of said resin to no more than 50Å or less.
Claim 6
Dependent Claim
17 words
A method as claimed in claim 1 including curing said resin for no more than 120 seconds.
Claim 7
Dependent Claim
20 words
A method as claimed in claim 1 including reducing the thickness of the oxide film to no more than 20Å.
Claim 8
Independent Claim
182 words
A method of manufacturing semiconductor devices comprising: plating the surface of a copper-alloy lead frame with copper; bonding a semiconductor pellet having electrodes to the copper plating on a die pad of said plated lead frame with a resin; curing said resin by heating said lead frame, said resin, and said semiconductor pellet in a non-oxidizing atmosphere having an oxygen concentration of no more than 1000 ppm; reducing the thickness of an oxide film formed on said plated lead frame during the curing of said resin in a deoxidizing atmosphere having an oxygen concentration of no more than 500 ppm; transferring said plated lead frame with the reduced thickness oxide film to a deoxidizing atmosphere having an oxygen concentration at the surface of said plated lead frame of no more than 3000 ppm; and wire-bonding wires between said electrodes of said semiconductor pellet and leads of said plated lead frame within 12 seconds of transfer of said plated lead frame to the deoxidizing atmosphere having an oxygen concentration at the surface of said plated lead frame of no more than 3000 ppm.
Claim 9
Independent Claim
182 words
A method of manufacturing semiconductor devices comprising: plating the surface of a copper-alloy lead frame with copper; bonding a semiconductor pellet having electrodes to the copper plating on a die pad of said plated lead frame with a resin; curing said resin by heating said lead frame, said resin, and said semiconductor pellet in a non-oxidizing atmosphere having an oxygen concentration of no more than 1000 ppm; reducing the thickness of an oxide film formed on said plated lead frame during the curing of said resin in a deoxidizing atmosphere having an oxygen concentration of no more than 500 ppm; transferring said plated lead frame with the reduced thickness oxide film to a deoxidizing atmosphere having an oxygen concentration at the surface of said plated lead frame of no more than 3000 ppm; and wire-bonding wires between said electrodes of said semiconductor pellet and leads of said plated lead frame within 12 seconds of transfer of said plated lead frame to the deoxidizing atmosphere having an oxygen concentration at the surface of said plated lead frame of no more than 3000 ppm.
Claim 10
Dependent Claim
13 words
A method as claimed in claim 7 wherein said non-oxidizing gas is nitrogen.
Claim 11
Dependent Claim
18 words
A method as claimed in claim 7 wherein said deoxidizing gas is a mixture of hydrogen and nitrogen.
Claim 12
Dependent Claim
33 words
A method as claimed in claim 7 including limiting the thickness of the oxide film on the surface of said plated lead frame during curing of said resin to no more than 50Å.
Claim 13
Dependent Claim
17 words
A method as claimed in claim 7 including curing said resin for no more than 120 seconds.
Claim 14
Dependent Claim
20 words
A method as claimed in claim 7 including reducing the thickness of the oxide film to no more than 20Å.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-02-10 | 1995-08-12 | 1996-02-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-02-10 | 1999-08-12 | 2000-02-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-02-10 | 2003-08-12 | 2004-02-11 | $7700.00 | Window Closed / Lapsed |