Patent US4511403A successfully refreshed from Google Patents.
US4511403A
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US
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Immersion tin composition and process for using
Assignee: Shipley Co Inc
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Filing: 1980-01-16
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Granted: 1985-04-16
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Expires: 2000-01-16
Abstract
Abstract This invention is for an immersion tin plating composition capable of depositing tin over metallic surfaces displaceable by tin and to processes using the same. The composition is characterized by an inhibitor that improves the plating characteristics of the solution and permits an increased ratio of thiourea to tin at a relatively high tin concentration without formation of "black tin". The tin plating compositions of this invention are capable of providing an increased yield of good quality tin compared to prior art tin plating compositions.
Inventors
- 👤 Alfred P. Orio
- 👤 Leonard R. Levy
- 👤 Michael Gulla
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 15:11
CPC Classifications
C; C23; C23C; C23C18/00; C23C18/16; C23C18/31
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
90 words
In an immersion plating solution for tin that plates over a base metal by displacement, said solution containing stannous ions in an amount of at least 0.05 moles per liter, thiourea in an amount such that the mole ratio of thiourea to stannous tin is at least 10:1, and a mineral acid in an amount sufficient to reduce the solution pH to below 1, the improvement comprising an aromatic mononuclear sulfonic acid in solution in an amount sufficient to prevent the formation of a loosely adherent, discolored immersion tin deposit.
Claim 2
Dependent Claim
90 words
In an immersion plating solution for tin that plates over a base metal by displacement, said solution containing stannous ions in an amount of at least 0.05 moles per liter, thiourea in an amount such that the mole ratio of thiourea to stannous tin is at least 10:1, and a mineral acid in an amount sufficient to reduce the solution pH to below 1, the improvement comprising an aromatic mononuclear sulfonic acid in solution in an amount sufficient to prevent the formation of a loosely adherent, discolored immersion tin deposit.
Claim 3
Dependent Claim
8 words
The solution of claim 1 containing a hypophosphite.
Claim 4
Dependent Claim
14 words
The solution of claim 1 where the sulfonic acid is a phenol sulfonic acid.
Claim 5
Dependent Claim
22 words
The solution of claim 1 where the stannous ions are present in an amount of from 0.05 to 0.2 moles per liter.
Claim 6
Dependent Claim
17 words
The solution of claim 4 where the ratio of thiourea to stannous ions is at least 12:1.
Claim 7
Dependent Claim
19 words
The solution of claim 4 where the ratio of thiourea to stannous ions varies between about 18:1 and 30:1.
Claim 8
Dependent Claim
28 words
The solution of claim 6 where the sulfonic acid is present in an amount varying between 0.01 grams per liter and that amount that retards the displacement reaction.
Claim 9
Dependent Claim
22 words
The solution of claim 7 where the sulfonic acid is present in an amount of from 0.1 to 3 grams per liter.
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) | 1988-04-15 | 1988-10-15 | 1989-04-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-04-15 | 1992-10-15 | 1993-04-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-04-15 | 1996-10-15 | 1997-04-16 | $7700.00 | Window Closed / Lapsed |