Patent US4537799A successfully refreshed from Google Patents.
US4537799A
Expired / Lapsed
US
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Selective metallization process
Assignee: AT&T Inc
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Filing: 1984-04-16
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Granted: 1985-08-27
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Expires: 2004-04-16
Abstract
Abstract A selective metallization process particularly suited for making printed circuit boards comprises the step of treating a substrate having a negative mask thereon with a reactant, e.g., acetic acid, which modifies the surface of the mask without affecting the substrate so as to remove or prevent an active catalytic layer from remaining on the surface of the mask thereby preventing electroless plating on the mask.
Inventors
- 👤 II John K. Dorey
- 👤 Steven L. Schmidt
- 👤 Wesley P. Townsend
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 20:55
CPC Classifications
H; H05; H05K; H05K3/00; H05K3/10; H05K3/18; H05K3/181; H05K3/182; H05K3/184; C; C23; C23C; C23C18/00; C23C18/16; C23C18/1601; C23C18/1603; C23C18/1605; C23C18/1633; C23C18/1646; C23C18/165; C23C18/1651; C23C18/1653; C23C18/18; C23C18/20; C23C18/2006; C23C18/2046; C23C18/2053; C23C18/206; C23C18/2066; C23C18/22; C23C18/24; C23C18/26; C23C18/28; C23C18/30; H05K2203/00; H05K2203/07; H05K2203/0703; H05K2203/0706; H05K2203/0779; H05K2203/0783; H05K2203/0786; H05K2203/0789; H05K2203/14; H05K2203/1415
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
83 words
A selective metallization process comprising the steps of providing a patterned mask on a substrate, treating the patterned substrate so as to provide a catalytic layer thereon and electrolessly plating the catalyzed substrate with the patterned mask thereon, including the step of treating the patterned substrate with a weak acid reactant which modifies the surface of the mask without substantial attack or modification of the exposed substrate before catalyzation and prior to electroless plating so as to prevent electroless plating on the mask.
Claim 2
Dependent Claim
83 words
A selective metallization process comprising the steps of providing a patterned mask on a substrate, treating the patterned substrate so as to provide a catalytic layer thereon and electrolessly plating the catalyzed substrate with the patterned mask thereon, including the step of treating the patterned substrate with a weak acid reactant which modifies the surface of the mask without substantial attack or modification of the exposed substrate before catalyzation and prior to electroless plating so as to prevent electroless plating on the mask.
Claim 3
Dependent Claim
22 words
The method recited in claim 1, wherein the step of electroless plating comprises plating to the full desired thickness in one step.
Claim 4
Dependent Claim
37 words
The method recited in claim 1, wherein the electroless plating is a thin flash electroless deposit and wherein the full desired thickness is achieved by a second plating step, said plating step being either electroplatingor electroless plating.
Claim 5
Dependent Claim
30 words
The method recited in claim 1, wherein the substrate surface comprises an epoxy resin and including the step of swelling and etching said substrate prior to treatment with said reactant.
Claim 6
Dependent Claim
107 words
A selective metallization process comprising the steps of providing a patterned mask on a substrate, treating the patterned substrate so as to provide a catalytic layer thereon and electrolessly plating the catalyzed substrate with the patterned mask thereon, including the step of treating the patterned substrate with a weak acid reactant which modifies the surface of the mask without substantial attack or modification of the exposed substrate before and/or after catalyzation and prior to electroless plating so as to prevent electroless plating on the mask, said weak acid comprising an aqueous solution of a member of the group consisting of acetic acid, formic acid and propionic acid.
Claim 7
Dependent Claim
107 words
A selective metallization process comprising the steps of providing a patterned mask on a substrate, treating the patterned substrate so as to provide a catalytic layer thereon and electrolessly plating the catalyzed substrate with the patterned mask thereon, including the step of treating the patterned substrate with a weak acid reactant which modifies the surface of the mask without substantial attack or modification of the exposed substrate before and/or after catalyzation and prior to electroless plating so as to prevent electroless plating on the mask, said weak acid comprising an aqueous solution of a member of the group consisting of acetic acid, formic acid and propionic acid.
Claim 8
Dependent Claim
16 words
The method recited in claim 5, wherein the reactant is an aqueous solution of acetic acid.
Claim 9
Dependent Claim
30 words
The method recited in claim 5 wherein the substrate surface comprises an epoxy resin and including the step of swelling and etching said substrate with an etchant comprising chromic acid.
Claim 10
Dependent Claim
12 words
The method recited in claim 7, wherein the acid is acetic acid.
Claim 11
Dependent Claim
41 words
The method recited in claim 7, including the steps of neutralizing the chromic acid with a caustic solution subsequent to etching and prior to treatment with said reactant and further treating the substrate with a hydrochloric acid accelerator subsequent to catalyzation.
Claim 12
Dependent Claim
98 words
A selective metallization process comprising providing a patterned negative mask on at least one surface of a substrate, said surface comprising an epoxy resin, treating the patterned substrate so as to create micropores on the exposed substrate, treating the patterned substrate with a weak acid reactant which modifies the surface of the mask without attacking the substrate surface, so as to prevent electroless plating on the mask then catalyzing the patterned substrate and electrolessly plating the catalyzed substrate with the mask still intact thereon such that said plating occurs on the exposed substrate but not on the mask.
Claim 13
Dependent Claim
98 words
A selective metallization process comprising providing a patterned negative mask on at least one surface of a substrate, said surface comprising an epoxy resin, treating the patterned substrate so as to create micropores on the exposed substrate, treating the patterned substrate with a weak acid reactant which modifies the surface of the mask without attacking the substrate surface, so as to prevent electroless plating on the mask then catalyzing the patterned substrate and electrolessly plating the catalyzed substrate with the mask still intact thereon such that said plating occurs on the exposed substrate but not on the mask.
Claim 14
Dependent Claim
27 words
The process recited in claim 10, wherein the weak acid is at least one member of the group consisting of acetic acid, formic acid and propionic acid.
Claim 15
Dependent Claim
30 words
The process recited in claim 10, wherein the micropores are formed in the substrate by etching the substrate in a chromic acid bath and wherein said reactant is acetic acid.
Claim 16
Dependent Claim
28 words
The process recited in claim 12 including the step of neutralizing the chromic acid on the substrate with a caustic solution prior to treatment with said acetic acid.
Claim 17
Dependent Claim
23 words
The process recited in claim 13, including the step of treating the catalyzed substrate with a hydrochloric acid solution prior to electroless plating.
Claim 18
Dependent Claim
18 words
The process recited in claim 13, wherein a thin flash electroless deposit is formed over the catalyzed substrate.
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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) | 1988-08-26 | 1989-02-25 | 1989-08-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-08-26 | 1993-02-25 | 1993-08-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-08-26 | 1997-02-25 | 1997-08-27 | $7700.00 | Window Closed / Lapsed |