US5950907A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ternary solder for the enhancement of C-4 fatigue life
Assignee: International Business Machines Corp
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Filing: 1997-03-26
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Granted: 1999-09-14
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Expires: 2017-03-26
Abstract
Abstract An enhanced fatigue life solder comprising, by weight, about 1-3% tin, about 1-3% silver and the balance essentially lead is provided. The solder is particularly useful for joining electronic components and in particular for making C-4 interconnections. A method for using the solder to make electronic components and electric components made using the method are also provided.
Inventors
- 👤 Giulio DiGiacomo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 12:57
CPC Classifications
H; H10; H10W; H10W72/00; B; B23; B23K; B23K35/00; B23K35/22; B23K35/24; B23K35/26; B23K35/268; H10W72/071; H10W72/072; H10W72/07231; H10W72/07236; H10W72/20; H10W72/251; H10W72/252
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
110 words
A method for making solder bump electrical interconnections between pads on a first substrate and corresponding pads on a second substrate comprising the steps of: applying the solder to pads on the first substrate, the solder comprising, by weight, about 1-3% tin, about 1-3% silver and the balance essentially lead; aligning the pads of the second substrate to be joined to the corresponding pads and solder bumps of the first substrate; heating the aligned first and second substrate to a temperature sufficient to form a solder interconnection between the pads of the first and second substrates and wherein the solder interconnection contains Ag 3 Sn precipitate distributed throughout the solder.
Claim 2
Independent Claim
110 words
A method for making solder bump electrical interconnections between pads on a first substrate and corresponding pads on a second substrate comprising the steps of: applying the solder to pads on the first substrate, the solder comprising, by weight, about 1-3% tin, about 1-3% silver and the balance essentially lead; aligning the pads of the second substrate to be joined to the corresponding pads and solder bumps of the first substrate; heating the aligned first and second substrate to a temperature sufficient to form a solder interconnection between the pads of the first and second substrates and wherein the solder interconnection contains Ag 3 Sn precipitate distributed throughout the solder.
Claim 3
Dependent Claim
21 words
The method of claim 1 wherein the first substrate is a semiconductor chip and the second substrate is a multilayer ceramic.
Claim 4
Dependent Claim
17 words
The method of claim 2 wherein the tin is about 1-2% and the silver is about 1-2%.
Claim 5
Dependent Claim
16 words
The method of claim 3 wherein the solder comprises about 1.25%-1.75% tin and about 1.25%-1.75% silver.
Claim 6
Dependent Claim
16 words
The method of claim 3 wherein the solder comprises about 1.4%-1.6% tin and about 1.4%-1.6% silver.
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) | 2002-09-13 | 2003-03-15 | 2003-09-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-09-13 | 2007-03-15 | 2007-09-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-09-13 | 2011-03-15 | 2011-09-14 | $7700.00 | Window Closed / Lapsed |