US5304252A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of removing a permanent photoimagable film from a printed circuit board
Assignee: Oliver Sales Co
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Filing: 1992-08-28
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Granted: 1994-04-19
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Expires: 2012-08-28
Abstract
Abstract A method to remove permanent photoimagable solder mask simultaneously from the insulating laminate and conductive metal traces of a printed circuit board comprising the steps of heating a photoimagable solder mask removing solution comprised of an aqueous alkaline solution, an organic penetrating and softening agent and a tarnish and corrosion inhibitor, contacting the solution with the permanent photoimagable solder mask on the printed circuit board, allowing the permanent photoimagable solder mask to soften, and removing the photoimagable solder mask removing solution and softened permanent photoimagable solder mask simultaneously from the insulating laminate and conductive metal traces of the circuit board by rinsing the board with water.
Inventors
- 👤 Richard C. Condra
- 👤 Paul C. Healey
- 👤 Michael R. Cochren
- 👤 Eddie L. Wright
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 18:52
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/26; G03F7/42; G03F7/422; G03F7/425; H; H05; H05K; H05K3/00; H05K3/22; H05K3/28; H05K3/288; H05K2203/00; H05K2203/07; H05K2203/0756; H05K2203/0769; H05K2203/0779; H05K2203/0786; H05K2203/0793; H05K3/285; H05K3/287
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
160 words
A method for removing a epoxy acrylic copolymer photoimagable solder mask of a negative resist simultaneously from the insulating laminate and conductive metal braces of a printed circuit board comprising the steps of: (a) contacting the permanent photoimagable solder mask on the insulating laminate and conductive metal traces of the printed circuit board with solder mask removing solution containing water and an activator compound chosen from a group consisting of a hydroxide or alkali metal silicate and of a concentration greater than twelve pars per hundred by weight; (b) heating the solder mask removing solution to a temperature between 140 and 210 degrees Fahrenheit; (c) allowing the solder mask removing solution to continue contact with the permanent photoimagable solder mask for a period of time of one hour to soften the permanent photoimagable solder mask; and (d) removing the solder mask removing solution and softened permanent photoimagable solder mask from the laminate and conductive metal traces on the circuit board.
Claim 2
Independent Claim
160 words
A method for removing a epoxy acrylic copolymer photoimagable solder mask of a negative resist simultaneously from the insulating laminate and conductive metal braces of a printed circuit board comprising the steps of: (a) contacting the permanent photoimagable solder mask on the insulating laminate and conductive metal traces of the printed circuit board with solder mask removing solution containing water and an activator compound chosen from a group consisting of a hydroxide or alkali metal silicate and of a concentration greater than twelve pars per hundred by weight; (b) heating the solder mask removing solution to a temperature between 140 and 210 degrees Fahrenheit; (c) allowing the solder mask removing solution to continue contact with the permanent photoimagable solder mask for a period of time of one hour to soften the permanent photoimagable solder mask; and (d) removing the solder mask removing solution and softened permanent photoimagable solder mask from the laminate and conductive metal traces on the circuit board.
Claim 3
Dependent Claim
24 words
The method called or in claim 1 wherein the hydroxide is chosen from a group comprised of alkali metal hydroxides, or quaternary ammonium hydroxide.
Claim 4
Dependent Claim
29 words
The method called for in claim 1 wherein the aqueous solution contains a corrosion inhibiting and tarnish retarding compound of between 0.001 to 5.0 parts per hundred by weight.
Claim 5
Dependent Claim
40 words
The method called for in claim 1 wherein the solder mask removing solution includes an organic penetrating and softening agent is chosen from a group consisting of pyrrolidones, lower molecular weight amides or glycol ethers of lower molecular weight alcohols.
Claim 6
Dependent Claim
17 words
The method called for in claim 1 including the step of agitating the solder mask removing solution.
Claim 7
Dependent Claim
20 words
The method called for in claim 1 including the step of spraying the solder mask removing solution onto the board.
Claim 8
Dependent Claim
29 words
The method called for in claim 1 wherein the step of removing the solder mask removing solution and softened permanent photoimagable solder mask comprises rinsing the board in water.
Claim 9
Dependent Claim
19 words
The method called for in claim 7 including the step of heating the water prior to rinsing the board.
Claim 10
Dependent Claim
20 words
The method called for in claim 7 including the step of agitating the water during the rinse of the board.
Claim 11
Dependent Claim
17 words
The method called for in claim 7 including the step of spraying the water on the board.
Claim 12
Independent Claim
157 words
A method for removing an epoxy acrylic copolymer, photoimagable solder mask of a negative resist simultaneously from the insulating laminate and conductive metal traces of a printed circuit board comprising the steps of: (a) contacting the permanent photoimagable solder ask on the insulating laminate and conductive metal traces of a printed circuit board with solder mask removing solution containing water and an activator compound chosen from a group consisting of a hydroxide or alkali metal silicate and of a concentration greater than twelve parts per hundred by weight; (b) heating the solder mask removing solution to a temperature between 160 and 210 degrees Fahrenheit; (c) allowing the solder mask removing solution to continue contact with the permanent photoimagable solder mask for a sufficient time to soften the permanent photoimagable solder mask; and (d) removing the solder mask removing solution and softened permanent photoimagable solder mask simultaneously from the insulating laminate and conducive traces of the circuit board.
Claim 13
Independent Claim
157 words
A method for removing an epoxy acrylic copolymer, photoimagable solder mask of a negative resist simultaneously from the insulating laminate and conductive metal traces of a printed circuit board comprising the steps of: (a) contacting the permanent photoimagable solder ask on the insulating laminate and conductive metal traces of a printed circuit board with solder mask removing solution containing water and an activator compound chosen from a group consisting of a hydroxide or alkali metal silicate and of a concentration greater than twelve parts per hundred by weight; (b) heating the solder mask removing solution to a temperature between 160 and 210 degrees Fahrenheit; (c) allowing the solder mask removing solution to continue contact with the permanent photoimagable solder mask for a sufficient time to soften the permanent photoimagable solder mask; and (d) removing the solder mask removing solution and softened permanent photoimagable solder mask simultaneously from the insulating laminate and conducive traces of the circuit board.
Claim 14
Independent Claim
180 words
A method for removing a epoxy acrylic copolymer photoimagable solder mask of a negative resist simultaneously from the insulating laminate and conductive metal traces of a printed circuit board comprising the steps of: (a) contacting the permanent photoimagable solder mask on the insulating laminate and conductive traces of the printed circuit board with solder mask removing solution containing water, sodium hydroxide of a concentration between twelve and forty parts per hundred by weight, a softening agent of N-methyl pyrrolidone of 7.5 to 12 parts per hundred by weight and a corrosion inhibitor of tolyltriazole of between 0.025 and 1 part per hundred by weight; (b) heating the solder mask removing solution to a temperature between 160 and 210 degrees Fahrenheit; (c) allowing the solder mask removing solution to continue contact with the permanent photoimagable solder mask for a period of time of less than one hour to soften the permanent photoimagable solder mask; and (d) removing the solder mask removing solution and softened permanent photoimagable solder mask simultaneously from the insulating laminate and conducive metal traces of the circuit board.
Claim 15
Independent Claim
180 words
A method for removing a epoxy acrylic copolymer photoimagable solder mask of a negative resist simultaneously from the insulating laminate and conductive metal traces of a printed circuit board comprising the steps of: (a) contacting the permanent photoimagable solder mask on the insulating laminate and conductive traces of the printed circuit board with solder mask removing solution containing water, sodium hydroxide of a concentration between twelve and forty parts per hundred by weight, a softening agent of N-methyl pyrrolidone of 7.5 to 12 parts per hundred by weight and a corrosion inhibitor of tolyltriazole of between 0.025 and 1 part per hundred by weight; (b) heating the solder mask removing solution to a temperature between 160 and 210 degrees Fahrenheit; (c) allowing the solder mask removing solution to continue contact with the permanent photoimagable solder mask for a period of time of less than one hour to soften the permanent photoimagable solder mask; and (d) removing the solder mask removing solution and softened permanent photoimagable solder mask simultaneously from the insulating laminate and conducive metal traces of the circuit board.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-04-18 | 1997-10-18 | 1998-04-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-04-18 | 2001-10-18 | 2002-04-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-04-18 | 2005-10-18 | 2006-04-19 | $7700.00 | Window Closed / Lapsed |