US4921550A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Delayed reflow alloy mix solder paste
Assignee: Texas Instruments Inc
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Filing: 1989-07-21
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Granted: 1990-05-01
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Expires: 2009-07-21
Abstract
Abstract A solder paste mixture for soldering surface mount devices to a circuit board using a reflow soldering process which utilizes a vapor phase furnace. The solder paste mixture has a metallic content which is 63% tin and 37% lead. The metallic content of the paste consists of 150 micron particles of 100% tin and 150 micron particles of an alloy of 10% tin and 90% lead. Included in the process of soldering components to the circuit board is the step of prebaking the circuit board with solder paste and components in their proper place on the board.
Inventors
- 👤 Neil R. McLellan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 05:18
CPC Classifications
H; H05; H05K; H05K3/00; H05K3/30; H05K3/32; H05K3/34; H05K3/3465; H05K3/3485; B; B23; B23K; B23K35/00; B23K35/22; B23K35/24; B23K35/26; B23K35/36; H05K2201/00; H05K2201/02; H05K2201/0203; H05K2201/0263; H05K2201/0272; H05K3/346
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
49 words
A process for delaying solder melt and for minimizing the number and size of voids in a solder joint, comprising the steps of: prebaking a circuit board with solder paste on the circuit board footpads, and then soldering surface mount devices to the board in a vapor phase furnace.
Claim 2
Dependent Claim
49 words
A process for delaying solder melt and for minimizing the number and size of voids in a solder joint, comprising the steps of: prebaking a circuit board with solder paste on the circuit board footpads, and then soldering surface mount devices to the board in a vapor phase furnace.
Claim 3
Dependent Claim
56 words
The process of claim 1 in which the solder paste metal content is approximately sixty-three percent tin and thirty-seven percent lead, by weight, and wherein the solder paste metal is in the form of particles of one hundred percent tin and particles of an alloy of approximately ten percent tin and ninety percent lead by weight.
Claim 4
Dependent Claim
31 words
The process of claim 3 in which the prebaking is done with the surface mount integrated circuit devices on the circuit board in their proper positions for soldering to the board.
Claim 5
Dependent Claim
21 words
The process of claim 2 in which the prebaking takes place at a temperature of approximately one hundred five degrees centigrade.
Claim 6
Dependent Claim
16 words
The process of claim 4 in which the prebaking lasts for approximately one to four hours.
References Cited (Backward Citations)
US4373974A
Cited
US4509994A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-04-30 | 1993-10-30 | 1994-05-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-04-30 | 1997-10-30 | 1998-05-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-04-30 | 2001-10-30 | 2002-05-01 | $7700.00 | Window Closed / Lapsed |