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US5017267A
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Composition and method for stripping tin or tin-lead alloy from copper surfaces
Assignee: MacDermid Acumen Inc
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Filing: 1990-07-17
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Granted: 1991-05-21
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Expires: 2010-07-17
Abstract
Abstract An aqueous composition for stripping tin or solder, as well as any underlying copper-tin alloy, from copper surfaces, containing an alkane sulfonic acid, preferably methane sulfonic acid, ferric nitrate, and a source of chlorate ion. The composition effects stripping without any appreciable formation of sludge or precipitate or suspended particles, and the chlorate component enables significant reduction in the concentration of alkane sulfonic acid otherwise needed for the stripping. Also described are stripping compositions containing a source of chlorate ion and an acid for solubilizing stripped tin or tin-lead, such as alkane sulfonic acid, acetic acid, formic acid and the like.
Inventors
- 👤 John L. Cordani
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 17:36
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/10; C23F1/14; C23F1/16; C23F1/30; C23F1/44; H; H05; H05K; H05K3/00; H05K3/02; H05K3/06; H05K3/067
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
82 words
A composition for stripping tin or tin-lead alloy, and any underlying copper-tin alloy, from a copper surface, without bringing about significant formation of sludge, precipitate or suspended by-products, comprising an aqueous solution of an alkane sulfonic acid, ferric nitrate and a solution-soluble source of chlorate ion, each in amounts such that the composition is effective to strip said tin or tin-lead alloy, and any underlying copper-tin alloy, from said copper surface without bringing about significant formation of sludge, precipitate or suspended by-products.
Claim 2
Dependent Claim
82 words
A composition for stripping tin or tin-lead alloy, and any underlying copper-tin alloy, from a copper surface, without bringing about significant formation of sludge, precipitate or suspended by-products, comprising an aqueous solution of an alkane sulfonic acid, ferric nitrate and a solution-soluble source of chlorate ion, each in amounts such that the composition is effective to strip said tin or tin-lead alloy, and any underlying copper-tin alloy, from said copper surface without bringing about significant formation of sludge, precipitate or suspended by-products.
Claim 3
Dependent Claim
70 words
A composition according to claim 1 wherein said alkane sulfonic acid is present in said aqueous solution in an amount of from about 10 to about 1500 g/l, said ferric nitrate is present in said aqueous solution in an amount of from about 1 g/l to saturation, and, wherein said source of chlorate ion is present in said aqueous solution in an amount of from about 0.1 g/l to saturation.
Claim 4
Dependent Claim
23 words
A composition according to claim 2 wherein the amount of alkane sulfonic acid in said aqueous solution is less than about 500 g/l.
Claim 5
Dependent Claim
17 words
A composition according to claim 1 consisting essentially of alkane sulfonic acid, ferric nitrate and solution-soluble chlorate.
Claim 6
Dependent Claim
10 words
A composition according to claim 4 further containing nitric acid.
Claim 7
Dependent Claim
15 words
A composition according to claim 1 wherein said alkane sulfonic acid is methane sulfonic acid.
Claim 8
Dependent Claim
15 words
A composition according to claim 1 wherein said source of chlorate ion is sodium chlorate.
Claim 9
Dependent Claim
71 words
A composition for stripping tin or tin-lead alloy, and any underlying copper-tin alloy, from a copper surface, consisting essentially of an aqueous solution of methane sulfonic acid, ferric nitrate, sodium chlorate and nitric acid, each in amounts such that the composition is effective to strip said tin or tin-lead alloy, and any underlying copper-tin alloy, from said copper surface, without bringing about substantial formation of sludge, precipitate or suspended by products.
Claim 10
Dependent Claim
71 words
A composition for stripping tin or tin-lead alloy, and any underlying copper-tin alloy, from a copper surface, consisting essentially of an aqueous solution of methane sulfonic acid, ferric nitrate, sodium chlorate and nitric acid, each in amounts such that the composition is effective to strip said tin or tin-lead alloy, and any underlying copper-tin alloy, from said copper surface, without bringing about substantial formation of sludge, precipitate or suspended by products.
Claim 11
Dependent Claim
24 words
A composition according to claim 8 wherein the amount of said alkane sulfonic acid in said aqueous solution is less than about 500 g/l.
Claim 12
Independent Claim
82 words
A method for stripping tin or tin-lead alloy, and any underlying copper-tin alloy, from a copper surface, comprising contacting said surface with a composition comprising an aqueous solution of an alkane sulfonic acid, ferric nitrate and a solution-soluble source of chlorate ion, each present in said composition in amounts such that the composition is effective for said stripping without bringing about substantial formation of sludge, precipitate or suspended by-products, for a time and at a temperature effective to bring about said stripping.
Claim 13
Independent Claim
82 words
A method for stripping tin or tin-lead alloy, and any underlying copper-tin alloy, from a copper surface, comprising contacting said surface with a composition comprising an aqueous solution of an alkane sulfonic acid, ferric nitrate and a solution-soluble source of chlorate ion, each present in said composition in amounts such that the composition is effective for said stripping without bringing about substantial formation of sludge, precipitate or suspended by-products, for a time and at a temperature effective to bring about said stripping.
Claim 14
Dependent Claim
39 words
A method according to claim 10 wherein said composition contains from about 10 to about 1500 g/l alkane sulfonic acid, from about 1 g/l to saturation ferric nitrate, and from about 0.1 g/l to saturation source of chlorate ion.
Claim 15
Dependent Claim
18 words
A method according to claim 11 wherein said composition contains less than about 500 g/l alkane sulfonic acid.
Claim 16
Dependent Claim
13 words
A method according to claim 12 wherein said composition further comprises nitric acid.
Claim 17
Dependent Claim
26 words
A method according to claim 10 wherein said composition consists essentially of an aqueous solution of methane sulfonic acid, ferric nitrate, sodium chlorate and nitric acid.
Claim 18
Dependent Claim
15 words
A method according to claim 10 wherein said temperature is less than about 120° F.
Claim 19
Dependent Claim
32 words
A method according to claim 10 wherein said copper surface is a copper surface of a printed circuit board, and wherein said printed circuit board further contains a patterned organic resist thereon.
Claim 20
Dependent Claim
29 words
A method according to claim 10 wherein said contacting is selected from the group consisting of immersing said surface in said solution and spraying said solution on said surface.
Claim 21
Dependent Claim
36 words
A composition for stripping tin or tin-lead alloy from a copper surface, comprising an aqueous solution of a solution-soluble source of chlorate ion and an acid effective to solubilize tin or tin-lead stripped from said surface.
Claim 22
Dependent Claim
36 words
A composition for stripping tin or tin-lead alloy from a copper surface, comprising an aqueous solution of a solution-soluble source of chlorate ion and an acid effective to solubilize tin or tin-lead stripped from said surface.
Claim 23
Dependent Claim
14 words
A composition according to claim 18 wherein said solubilizing acid is an organic acid.
Claim 24
Dependent Claim
22 words
A composition according to claim 19 wherein said organic acid is selected from the group consisting of acetic acid and formic acid.
Claim 25
Dependent Claim
15 words
A composition according to claim 18 wherein said solubilizing acid is an alkane sulfonic acid.
Claim 26
Dependent Claim
19 words
A composition according to claim 18 consisting essentially of an aqueous solution of sodium chlorate and methane sulfonic acid.
References Cited (Backward Citations)
US3677949A
Cited
US3926699A
Cited
US4004956A
Cited
US3990982A
Cited
US4306933A
Cited
US4297257A
Cited
US4374744A
Cited
US4424097A
Cited
US4439338A
Cited
US4397753A
Cited
US4673521A
Cited
US4687545A
Cited
US4713144A
Cited
US4919752A
Cited
US4957653A
Cited
US4944851A
Cited
US4921571A
Cited
US4921571B1
Cited
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