US5288332A
Expired / Lapsed
US
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A process for removing corrosive by-products from a circuit assembly
Assignee: CHAMPION RONALD E
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Filing: 1993-02-05
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Granted: 1994-02-22
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Expires: 2013-02-05
Abstract
Abstract The invention is a process for removing corrosive by-products from semiconductor assembly by applying an aqueous spray comprising a saponifying agent to release and dissolve flux constituents and applying an acidic aqueous spray to the assembly to dissolve metal contaminants. While the acid source in the aqueous spray may be any number of constituents, preferably carbon dioxide is used. Metal released by the aqueous acid spray is inactivated and bound by a chelating agent which is introduced into the wash. The invention is applicable to any semiconductor device or assembly made through processes using bonding materials such as solder which may have by-products which are corrosive or otherwise deleterious to the device or device assembly once placed in the chosen environment of use.
Inventors
- 👤 Cecil S. Pustilnik
- 👤 George E. Shannon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 15:23
CPC Classifications
H; H10; H10W; H10W99/00; C; C23; C23G; C23G1/00; H05; H05K; H05K3/00; H05K3/22; H05K3/26; H10W70/00; H10W70/01; H10W70/05; H10W70/097; H05K2203/00; H05K2203/07; H05K2203/0779; H05K2203/0786; H05K2203/0789; H05K2203/0793; H05K2203/12; H05K2203/121
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
60 words
A process for removing corrosive by-products from a circuit assembly, said process comprising the steps of: (a) applying an aqueous flush to the assembly, said aqueous flush comprising an effective saponifying amount of an alkaline agent; (b) applying an acidic aqueous wash to the assembly; and (c) treating the acid aqueous wash with an effective amount of a chelating agent.
Claim 2
Dependent Claim
60 words
A process for removing corrosive by-products from a circuit assembly, said process comprising the steps of: (a) applying an aqueous flush to the assembly, said aqueous flush comprising an effective saponifying amount of an alkaline agent; (b) applying an acidic aqueous wash to the assembly; and (c) treating the acid aqueous wash with an effective amount of a chelating agent.
Claim 3
Dependent Claim
24 words
The process of claim 1 wherein said aqueous alkaline flush is applied for a time period ranging from about 5 minutes to 30 minutes.
Claim 4
Dependent Claim
23 words
The process of claim 1 wherein said aqueous alkaline flush is applied at a temperature ranging from about 40° C. to 70° C.
Claim 5
Dependent Claim
28 words
The process of claim 1 wherein said alkaline agent is selected from the group consisting of an amine source, an inorganic hydroxide, an amine hydroxide, or mixtures thereof.
Claim 6
Dependent Claim
14 words
The process of claim 1 wherein said aqueous alkaline flush is applied through agitation.
Claim 7
Dependent Claim
22 words
The process of claim 5 wherein said aqueous alkaline flush is applied at pressure ranging from about 20 psi to 100 psi.
Claim 8
Dependent Claim
23 words
The process of claim 1 wherein said alkaline agent source comprises ammonium in a concentration ranging from about 1 wt-% to 10 wt-%.
Claim 9
Dependent Claim
23 words
The process of claim 1 wherein said acidic aqueous wash comprises carbon dioxide present at a pH ranging from about 3 to 5.
Claim 10
Dependent Claim
23 words
The process of claim 1 wherein said aqueous acid wash is applied for a period ranging from about 1 minute to 5 minutes.
Claim 11
Dependent Claim
23 words
The process of claim 1 wherein said aqueous acidic wash is applied at a pressure ranging from about 10 psi to 40 psi.
Claim 12
Dependent Claim
17 words
The process of claim 1 comprising the additional step of rinsing the assembly with water after saponification.
Claim 13
Dependent Claim
68 words
A process for removing corrosion producing by-products, from a circuit assembly said process comprising the steps of: (a) applying an aqueous spray, said aqueous spray comprising an effective saponifying amount of an ammonium hydroxide source; (b) rinsing with water; (c) applying an aqueous spray comprising an effective acidifying amount of carbon dioxide; and (d) treating said acidified aqueous spray wash with an effective amount of ethylene diamine tetraacetate.
Claim 14
Dependent Claim
68 words
A process for removing corrosion producing by-products, from a circuit assembly said process comprising the steps of: (a) applying an aqueous spray, said aqueous spray comprising an effective saponifying amount of an ammonium hydroxide source; (b) rinsing with water; (c) applying an aqueous spray comprising an effective acidifying amount of carbon dioxide; and (d) treating said acidified aqueous spray wash with an effective amount of ethylene diamine tetraacetate.
Claim 15
Dependent Claim
16 words
The process of claim 12 wherein said saponifying aqueous ammonium hydroxide spray is applied through agitation.
Claim 16
Dependent Claim
23 words
The process of claim 12 wherein said saponifying ammonium hydroxide spray is applied at pressure ranging from about 10 psi to 70 psi.
Claim 17
Dependent Claim
26 words
The process of claim 12 wherein said aqueous spray comprising an alkaline agent comprises ammonium in a concentration ranging from about 1 wt-% to 10 wt-%.
Claim 18
Dependent Claim
22 words
The process of claim 12 wherein said aqueous spray comprises carbon dioxide present at a pH ranging from about 3 to 5.
Claim 19
Dependent Claim
27 words
The method of claim 12 wherein said ethylene diamine tetraacetate is present in the acidic spray in a concentration ranging from about 0.1 wt-% to 1 wt-%.
Claim 20
Dependent Claim
74 words
A process for removing corrosion producing by-products from a circuit assembly, said process comprising the steps of: (a) applying an alkaline aqueous spray, said aqueous spray comprising ammonium hydroxide present in a concentration ranging from about 1 wt-% to 10 wt-%; (b) applying an aqueous spray comprising a carbon dioxide present at a pH concentration ranging from about 1 to 7; and (c) treating said carbon dioxide containing aqueous spray with a chelating agent.
Claim 21
Dependent Claim
74 words
A process for removing corrosion producing by-products from a circuit assembly, said process comprising the steps of: (a) applying an alkaline aqueous spray, said aqueous spray comprising ammonium hydroxide present in a concentration ranging from about 1 wt-% to 10 wt-%; (b) applying an aqueous spray comprising a carbon dioxide present at a pH concentration ranging from about 1 to 7; and (c) treating said carbon dioxide containing aqueous spray with a chelating agent.
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