US5655703A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Solder hierarchy for chip attachment to substrates
Assignee: International Business Machines Corp
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Filing: 1995-05-25
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Granted: 1997-08-12
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Expires: 2015-05-25
Abstract
Abstract The method for soldering a chip to a substrate to form a module and then soldering the module to a circuit board includes selecting a three level hierarchy of solders by the temperature required to melt. By this method, a module can be soldered to and de-soldered from a circuit board without affecting adversely the solder between the chip and the substrate. The package formed by this method is free of faults that are caused frequently during both manufacture and service.
Inventors
- 👤 Miguel Angel Jimarez
- 👤 Amit Kumar Sarkhel
- 👤 Lawrence Harold White
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 18:14
CPC Classifications
B; B23; B23K; B23K1/00; B23K1/0008; B23K1/0016; B23K35/00; B23K35/22; B23K35/24; B23K35/26; B23K35/262; B23K35/268; H; H05; H05K; H05K3/00; H05K3/30; H05K3/32; H05K3/34; H05K3/346; H10; H10W; H10W74/00; H10W74/01; H10W74/012; H10W74/10; H10W74/15; B23K2101/00; B23K2101/36; B23K2101/40; B23K35/001; H05K2201/00; H05K2201/09; H05K2201/09209; H05K2201/09372; H05K2201/094; H05K3/341; H05K3/3431; H10W72/00; H10W72/071; H10W72/072; H10W72/07231; H10W72/07236; H10W72/20; H10W72/251; H10W72/252; H10W72/851; H10W72/853; H10W72/856; H10W90/00; H10W90/701; H10W90/731; H10W90/734; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49117; Y10T29/49124; Y10T29/4913; Y10T29/49144
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
167 words
A method of forming a solder attachment between a chip and a substrate to fabricate a module that permits the module to be attached by soldering to a circuit board without affecting adversely the solder attachment of the chip, comprising: selecting a three level hierarchy of solders by the temperature required to melt, the first level being the highest temperature, and the third level being the lowest; applying a solder ball of said first level solder in said three level hierarchy at a point of attachment of a chip; applying solder of said second level solder in said three level hierarchy of solders at a point of attachment of said solder ball to a substrate to produce a module; and using solder of a third level solder in said three level hierarchy of solders for connecting said module to a circuit board; whereby said module may be soldered to or de-soldered from said circuit board without melting either said first level solder or said second level solder.
Claim 2
Independent Claim
167 words
A method of forming a solder attachment between a chip and a substrate to fabricate a module that permits the module to be attached by soldering to a circuit board without affecting adversely the solder attachment of the chip, comprising: selecting a three level hierarchy of solders by the temperature required to melt, the first level being the highest temperature, and the third level being the lowest; applying a solder ball of said first level solder in said three level hierarchy at a point of attachment of a chip; applying solder of said second level solder in said three level hierarchy of solders at a point of attachment of said solder ball to a substrate to produce a module; and using solder of a third level solder in said three level hierarchy of solders for connecting said module to a circuit board; whereby said module may be soldered to or de-soldered from said circuit board without melting either said first level solder or said second level solder.
Claim 3
Dependent Claim
27 words
A method as defined by claim 1 wherein said third level solder in said three level hierarchy of solders is solder composed of approximately 37% Pb--63% Sn.
Claim 4
Dependent Claim
27 words
A method as defined by claim 1 wherein said second level solder in said three level hierarchy of solders is solder composed of approximately 96.5% Sn--3.5% Ag.
Claim 5
Dependent Claim
28 words
A method as defined by claim 1 wherein said second level solder in said three level hierarchy of solders has a melting temperature of about 220-240 degrees C.
Claim 6
Dependent Claim
28 words
A method as defined by claim 1 wherein said third level solder in said three level hierarchy of solders has a melting temperature of about 180 degrees C.
Claim 7
Dependent Claim
37 words
A method as defined by claim 1 wherein said second level solder in said three level hierarchy of solders has a melting temperature intermediate the melting temperatures of said first level solder and said third level solder.
Claim 8
Dependent Claim
31 words
A method as defined by claim 1 wherein said first level solder in said three level hierarchy of solders is solder composed of approximately 90% to 97% Pb--10% to 3% Sn.
Claim 9
Dependent Claim
46 words
A method as defined by claim 7 wherein said second level solder in said three level hierarchy of solders is solder composed of approximately 96.5% Sn--3.5% Ag, and said third level solder in said three level hierarchy of solders is composed of approximately 37% Pb--63% Sn.
Claim 10
Dependent Claim
29 words
A method as defined by claim 1 wherein said first level solder in said three level hierarchy of solders has a melting temperature of at least 300 degrees C.
Claim 11
Dependent Claim
49 words
A method as defined by claim 9 wherein said second level solder in said three level hierarchy of solders has a melting temperature of about 220-240 degrees C, and said third level solder in said three level hierarchy of solders has a melting temperature of about 180 degrees C.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-08-11 | 2001-02-10 | 2001-08-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-08-11 | 2005-02-10 | 2005-08-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-08-11 | 2009-02-10 | 2009-08-12 | $7700.00 | Window Closed / Lapsed |