US3970239A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fluxing technique for removing lead oxide
Assignee: Arris Technology Inc
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Filing: 1975-08-14
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Granted: 1976-07-20
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Expires: 1995-08-14
Abstract
Abstract A process for removing lead oxide from the surface of the lead solder of a semiconductor assembly in the inert atmosphere of a joining furnace by introducing into the joining furnace an acetate compound capable of reacting with lead oxide at the joining furnace temperature to form a coordinated lead compound. Both the acetate compound and the coordinated lead compound are gases at the joining furnace temperature. The acetate compound is preferably glacial acetic acid, acetic anhydride, or mixtures thereof.
Inventors
- 👤 Michael Hill
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 09:08
CPC Classifications
B; B23; B23K; B23K35/00; B23K35/22; B23K35/38
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
79 words
A process for removing lead oxide from the surface of the lead solder of a semiconductor assembly in the inert atmosphere of a joining furnace comprising the step of: introducing into said joining furnace an acetate compound, said acetate compound being capable of reacting with said lead oxide at the temperature of said joining furnace to form at least one coordinated lead compound, said acetate compound and said coordinated lead compound both being gases at said joining furnace temperature.
Claim 2
Dependent Claim
79 words
A process for removing lead oxide from the surface of the lead solder of a semiconductor assembly in the inert atmosphere of a joining furnace comprising the step of: introducing into said joining furnace an acetate compound, said acetate compound being capable of reacting with said lead oxide at the temperature of said joining furnace to form at least one coordinated lead compound, said acetate compound and said coordinated lead compound both being gases at said joining furnace temperature.
Claim 3
Dependent Claim
13 words
The process of claim 1 wherein said acetate compound is glacial acetic acid.
Claim 4
Dependent Claim
12 words
The process of claim 1 wherein said acetate compound is acetic anhydride.
Claim 5
Dependent Claim
22 words
The process of claim 1 including the additional step of maintaining said joining furnace atmosphere at a temperature of at least 328°C.
Claim 6
Dependent Claim
21 words
The process of claim 1 including the additional step of maintaining said joining furnace atmosphere at a temperature of about 328°-420°C.
Claim 7
Dependent Claim
35 words
The process of claim 1 wherein said acetate compound is selected from the group consisting of glacial acetic acid, acetic anhydride, and mixtures thereof, and wherein said joining furnace temperature is maintained at about 328°-420°C.
Claim 8
Dependent Claim
17 words
The process of claim 1 wherein said acetate compound is introduced directly into said joining furnace atmosphere.
Claim 9
Dependent Claim
21 words
The process of claim 1 wherein said acetate compound is introduced into said joining furnace atmosphere along with said inert atmosphere.
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) | 1979-07-20 | 1980-01-19 | 1980-07-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-07-20 | 1984-01-19 | 1984-07-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-07-20 | 1988-01-19 | 1988-07-20 | $7700.00 | Window Closed / Lapsed |