US4921157A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fluxless soldering process
Assignee: RTI International
•
Filing: 1989-03-15
•
Granted: 1990-05-01
•
Expires: 2009-03-15
Abstract
Abstract A method of soldering without the need for fluxing agents, high temperature, hydrogen, laser excitation or sputtering techniques. The method uses plasma excitation to remove surface oxides from solder surfaces, thereby eliminating the need for post-soldering cleaning in an accurate and efficient manner, resulting in a higher quality and long term reliability solder joint. In addition, serious environmental problems caused by cleaning solvents are avoided.
Inventors
- 👤 Giora Dishon
- 👤 Stephen M. Bobbio
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 18:59
CPC Classifications
B; B23; B23K; B23K1/00; B23K1/20; B23K1/206; B23K35/00; B23K35/22; B23K35/38; C; C23; C23G; C23G5/00; H; H05; H05K; H05K3/00; H05K3/30; H05K3/32; H05K3/34; H05K3/3489; B23K2101/00; B23K2101/36; B23K2101/40
Claims Analysis
Total Claims: 47
Claim 1
Independent Claim
45 words
A method of soldering without the need for fluxing agents, comprising the steps of: a. depositing solder on a first surface, said solder having a surface oxide layer; b. performing fluorine-containing plasma excitation on said solder; and c. reflowing said solder on said first surface.
Claim 2
Independent Claim
45 words
A method of soldering without the need for fluxing agents, comprising the steps of: a. depositing solder on a first surface, said solder having a surface oxide layer; b. performing fluorine-containing plasma excitation on said solder; and c. reflowing said solder on said first surface.
Claim 3
Dependent Claim
35 words
The method of claim 1 wherein said reflowing step comprises placing said solder in contact with a second surface, to thereby solder join together said first and second surfaces without the need for post-soldering cleaning.
Claim 4
Dependent Claim
25 words
The method of claim 2 wherein said placing step is preceded by the step of coating both of said first and second surfaces with solder.
Claim 5
Dependent Claim
13 words
The method of claim 1 wherein said reflowing step occurs in a vacuum.
Claim 6
Dependent Claim
16 words
The method of claim 1 wherein said performing and reflowing steps occur in a continuous vacuum.
Claim 7
Dependent Claim
21 words
The method of claim 1 wherein said performing a fluorine plasma excitation step occurs at a temperature of approximately 34°-50° C.
Claim 8
Dependent Claim
25 words
The method of claim 1 wherein said performing a fluorine plasma excitation step comprises performing said fluorine plasma excitation for approximately one-half to three minutes.
Claim 9
Dependent Claim
13 words
The method of claim 1 wherein said reflow step occurs at low pressure.
Claim 10
Dependent Claim
13 words
The method of claim 1 wherein said reflow step occurs at high pressure.
Claim 11
Dependent Claim
23 words
The method of claim 1 wherein said performing a fluorine-containing plasma excitation step comprises the use of fluorine radicals as a reactive species.
Claim 12
Dependent Claim
14 words
The method of claim 1 wherein said performing and said reflowing steps occur simultaneously.
Claim 13
Dependent Claim
17 words
The method of claim 1 wherein said reflowing step occurs at a temperature of approximately 200° C.
Claim 14
Dependent Claim
25 words
The method of claim 1 wherein said performing step converts at least some of the surface oxides to a compound of the solder and fluorine.
Claim 15
Dependent Claim
16 words
The method of claim 1 wherein said performing step is preceded by an oxygen plasma treatment.
Claim 16
Independent Claim
68 words
A method of soldering without the need for fluxing agents, comprising the steps of: a. depositing a layer of solder on a first surface, said solder having a surface oxide layer; b. performing a fluorine-containing plasma excitation at room temperature on said solder to convert said surface oxides to a compound of solder and fluorine; and c. reflowing said solder on said first surface in a non-oxidizing ambient.
Claim 17
Independent Claim
68 words
A method of soldering without the need for fluxing agents, comprising the steps of: a. depositing a layer of solder on a first surface, said solder having a surface oxide layer; b. performing a fluorine-containing plasma excitation at room temperature on said solder to convert said surface oxides to a compound of solder and fluorine; and c. reflowing said solder on said first surface in a non-oxidizing ambient.
Claim 18
Dependent Claim
30 words
The method of claim 15 wherein said reflowing step comprises placing said solder in contact with a second surface to form a solder bond between said first and second surfaces.
Claim 19
Dependent Claim
17 words
The method of claim 15 wherein said reflowing step occurs at a temperature of approximately 200° C.
Claim 20
Dependent Claim
13 words
The method of claim 15 wherein said reflowing step occurs in a vacuum.
Claim 21
Dependent Claim
20 words
The method of claim 15 wherein said performing a fluorine-containing plasma treatment and reflowing steps occur in a continuous vacuum.
Claim 22
Dependent Claim
25 words
The method of claim 15 wherein said performing a fluorine-containing plasma excitation step comprises performing said fluorine plasma excitation for approximately one-half to three minutes.
Claim 23
Dependent Claim
14 words
The method of claim 15 wherein said reflow step occurs in a low pressure.
Claim 24
Dependent Claim
13 words
The method of claim 15 wherein said reflow step occurs at high pressure.
Claim 25
Dependent Claim
23 words
The method of claim 15 wherein said performing a fluorine-containing plasma excitation step comprises the use of fluorine radicals as a reactive species.
Claim 26
Dependent Claim
18 words
The method of claim 15 wherein said performing a fluorine-containing plasma excitation and said reflowing steps occur simultaneously.
Claim 27
Dependent Claim
16 words
The method of claim 15 wherein said performing step is preceded by an oxygen plasma treatment.
Claim 28
Independent Claim
67 words
A method of soldering which removes surface oxides from exposed solder surfaces without the need for fluxing agents, comprising the steps of: a. depositing solder on a first surface to be soldered; b. performing a fluorine-containing plasma excitation on said solder until sufficient fluorine compound forms on the exposed surface of said solder to permit wetting to occur; and c. reflowing said solder on said first surface.
Claim 29
Independent Claim
67 words
A method of soldering which removes surface oxides from exposed solder surfaces without the need for fluxing agents, comprising the steps of: a. depositing solder on a first surface to be soldered; b. performing a fluorine-containing plasma excitation on said solder until sufficient fluorine compound forms on the exposed surface of said solder to permit wetting to occur; and c. reflowing said solder on said first surface.
Claim 30
Dependent Claim
33 words
The method of claim 26 wherein said placing step comprises placing said treated solder in contact with a second surface to form a physical and electrical contact between said first and second surfaces.
Claim 31
Dependent Claim
17 words
The method of claim 26 wherein said reflowing step occurs at a temperature of approximately 200° C.
Claim 32
Dependent Claim
13 words
The method of claim 26 wherein said reflowing step occurs in a vacuum.
Claim 33
Dependent Claim
23 words
The method of claim 26 wherein said performing a plasma excitation step comprises performing said plasma excitation for approximately one-half to three minutes.
Claim 34
Dependent Claim
14 words
The method of claim 26 wherein said reflow step occurs in a low pressure.
Claim 35
Dependent Claim
14 words
The method of claim 26 wherein said reflow step occurs in a high pressure.
Claim 36
Dependent Claim
17 words
The method of claim 26 wherein said performing a plasma excitation step occurs at approximately 34°-50° C.
Claim 37
Dependent Claim
22 words
The method of claim 26 wherein said performing a plasma excitation step comprises the use of fluorine radicals as the reactive species.
Claim 38
Dependent Claim
17 words
The method of claim 26 wherein said performing a plasma excitation and said reflowing steps occur simultaneously.
Claim 39
Dependent Claim
25 words
The method of claim 29 wherein said placing step is preceded by the step of coating both of said first and second surfaces with solder.
Claim 40
Dependent Claim
16 words
The method of claim 26 wherein said performing step is preceded by an oxygen plasma treatment.
Claim 41
Dependent Claim
54 words
A fluxless soldering method for first and second surfaces comprising the steps of: a. providing a first surface having solder thereon, said solder having a surface oxide layer; and b. performing fluorine-containing plasma excitation on said solder; whereby said first surface may be soldered to a second surface without the need for post-soldering cleaning.
Claim 42
Dependent Claim
54 words
A fluxless soldering method for first and second surfaces comprising the steps of: a. providing a first surface having solder thereon, said solder having a surface oxide layer; and b. performing fluorine-containing plasma excitation on said solder; whereby said first surface may be soldered to a second surface without the need for post-soldering cleaning.
Claim 43
Dependent Claim
24 words
The method of claim 38 wherein said performing a fluorine-containing plasma excitation step comprises performing fluorine plasma excitation for approximately one-half to three minutes.
Claim 44
Dependent Claim
15 words
The method of claim 38 wherein said performing excitation step occurs at approximately 34°-50° C.
Claim 45
Dependent Claim
22 words
The method of claim 38 wherein said performing a plasma excitation step comprises the use of fluorine radicals as the reactive species.
Claim 46
Dependent Claim
28 words
The method of claim 38 wherein said performing a fluorine-containing plasma excitation step is performed until sufficient fluorine compound forms in said solder to permit wetting to occur.
Claim 47
Dependent Claim
16 words
The method of claim 38 wherein said performing step is preceded by an oxygen plasma treatment.
References Cited (Backward Citations)
US4081121A
Cited
EP0034041A1
Cited
US4405379A
Cited
US4504007A
Cited
US4498046A
Cited
DE3442538A1
Cited
US4577398A
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 |