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Patent US5755859A successfully refreshed from Google Patents.
US5755859A
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US
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Cobalt-tin alloys and their applications for devices, chip interconnections and packaging
Assignee: International Business Machines Corp
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Filing: 1995-08-24
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Granted: 1998-05-26
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Expires: 2015-08-24
Abstract
Abstract A process for electrolessly depositing cobalt-tin alloys with adjustable tin contents from 1 to over 25 atomic percent tin is disclosed. The deposited alloy is useful in the electronics and computer industries for device, chip interconnection and packaging applications. When used for chip interconnection applications, for example, the invention replaces the currently used complicated ball-limiting-metallurgy. The invention may also be used to inhibit hillock formation and electromigration in copper wire structures found in computers and micron dimension electronic devices.
Inventors
- 👤 Vlasta A. Brusic
- 👤 Jeffrey Robert Marino
- 👤 Eugene John O'Sullivan
- 👤 Carlos Juan Sambucetti
- 👤 Alejandro Gabriel Schrott
- 👤 Cyprian Emeka Uzoh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:30
CPC Classifications
C; C23; C23C; C23C18/00; C23C18/16; C23C18/48; C23C18/50; H; H05; H05K; H05K3/00; H05K3/22; H05K3/24; H05K3/244; H10; H10W; H10W72/00; H10W72/01; H10W72/012; H10W72/019; H10W72/20; H10W72/251; H10W72/252; H10W72/29; H10W72/90; H10W72/921; H10W72/923; H10W72/951; H10W72/952
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
31 words
A solution for the electroless deposition of cobalt-tin-phosphorus alloys comprising: a) a cobalt salt plus a tin salt; b) a complexing agent; c) a phosphorus-bearing reducing agent; and d) a buffer.
Claim 2
Dependent Claim
31 words
A solution for the electroless deposition of cobalt-tin-phosphorus alloys comprising: a) a cobalt salt plus a tin salt; b) a complexing agent; c) a phosphorus-bearing reducing agent; and d) a buffer.
Claim 3
Dependent Claim
19 words
The solution of claim 1 wherein said cobalt salt is cobalt sulfate and said tin salt is sodium stannate.
Claim 4
Dependent Claim
11 words
The solution of claim 1 wherein said reducing agent is hypophosphite.
Claim 5
Dependent Claim
12 words
The solution of claim 1 wherein said complexing agent is sodium citrate.
Claim 6
Dependent Claim
11 words
The solution of claim 1 wherein said buffer is ammonium hydroxide.
Claim 7
Dependent Claim
48 words
A method for the selective deposition of a Co-Sn-P alloy onto one or more device structures in a device comprising: (a) preparing the plating bath of claim 1; (b) activating the surfaces of said device structures; (c) rinsing said device; (d) immersing said device in said plating bath.
Claim 8
Dependent Claim
41 words
A solution for the electroless deposition of cobalt-tin-phosphorus alloys comprising: a) about 85 mm tri-sodium citrate; b) about 4 mM sodium stannate; c) about 0.1 M ammonium hydroxide; d) about 22 mM cobalt sulfate; and e) about 95 mM sodium hypophosphite.
Claim 9
Dependent Claim
41 words
A solution for the electroless deposition of cobalt-tin-phosphorus alloys comprising: a) about 85 mm tri-sodium citrate; b) about 4 mM sodium stannate; c) about 0.1 M ammonium hydroxide; d) about 22 mM cobalt sulfate; and e) about 95 mM sodium hypophosphite.
Claim 10
Dependent Claim
11 words
The solution of claim 7 further including about 1 mM surfactant.
Claim 11
Dependent Claim
11 words
The solution of claim 7 having a pH of about 8.6.
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) | 2001-05-25 | 2001-11-24 | 2002-05-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-05-25 | 2005-11-24 | 2006-05-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-05-25 | 2009-11-24 | 2010-05-26 | $7700.00 | Window Closed / Lapsed |