US3839083A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Selective metallization process
Assignee: Texas Instruments Inc
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Filing: 1972-10-06
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Granted: 1974-10-01
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Expires: 1992-10-06
Abstract
Abstract A process is disclosed for effecting selective metal deposition on insulating substrates. The substrate surface is conditioned and sensitized with suitable chemical solutions. The surface is then patterned by selective application of heat, such that unexposed areas are effective to reduce a precious metal from a precious metal salt solution. Electroless plating is then effective to form continuous metallic patterns. In a preferred embodiment this substrate is immersed in a solution containing tin chloride, the oxidation state of the metal ion thereof being alterable by exposure to heat. Subsequent to patterning, the unaltered metal ion is effective to reduce palladium from a palladium salt solution. The substrate surface is first conditioned to produce uniform metallization by immersing it in a solution containing a sodium salt of a strong base and a relatively weaker acid to produce a high density of nucleation sites.
Inventors
- 👤 Y Sihvonen
- 👤 J Woodham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 08:56
CPC Classifications
H; H05; H05K; H05K3/00; H05K3/10; H05K3/18; H05K3/181; H05K3/182; C; C23; C23C; C23C18/00; C23C18/16; C23C18/1601; C23C18/1603; C23C18/1607; C23C18/1608; C23C18/1612; C23C18/1633; C23C18/1646; C23C18/165; C23C18/1653; H05K2203/00; H05K2203/10; H05K2203/107; H05K3/185
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
127 words
IN A METHOD FOR SELECTIVELY DEPOSITING A PRECIOUS METAL ON AN INSULATING SUBSTRATE, THE STEPS OF: IMMERSING SAID SUBSTRATE IN A SOLUTION CONTAINING A SALT OF A METAL SELECTED FROM THE GROUP CONSISTING OF TIN, TITANIUM AND LEAD, THE OXIDATION STATE OF THE METAL IONS THEREOF BEING ALTERABLE BY EXPOSURE TO HEAT, TO PROVIDE A COATING OF SAID SOLUTION ON SAID SUBSTRATE, AND PRODUCING A PATTERN CAPABLE OF REDUCING SAID PECIOUS METAL FROM A PRECIOUS METAL SALT THEREOF BY SELECTIVELY EXPOSING PORTIONS OF SAID COATED SUBSTRATE TO HEAT TO EFFECTIVELY CHANGE THE OXIDATION STATE OF SAID METAL IONS AT SAID PORTIONS WITH THE RESULT THAT SAID METLA IONS OF SAID PORTIONS OF SAID COATED SUBSTRATE SO EXPOSED TO HEAT ARE RENDERED INCAPABLE OF REDUCING SAID PRECIOUS METAL.
Claim 2
Dependent Claim
127 words
IN A METHOD FOR SELECTIVELY DEPOSITING A PRECIOUS METAL ON AN INSULATING SUBSTRATE, THE STEPS OF: IMMERSING SAID SUBSTRATE IN A SOLUTION CONTAINING A SALT OF A METAL SELECTED FROM THE GROUP CONSISTING OF TIN, TITANIUM AND LEAD, THE OXIDATION STATE OF THE METAL IONS THEREOF BEING ALTERABLE BY EXPOSURE TO HEAT, TO PROVIDE A COATING OF SAID SOLUTION ON SAID SUBSTRATE, AND PRODUCING A PATTERN CAPABLE OF REDUCING SAID PECIOUS METAL FROM A PRECIOUS METAL SALT THEREOF BY SELECTIVELY EXPOSING PORTIONS OF SAID COATED SUBSTRATE TO HEAT TO EFFECTIVELY CHANGE THE OXIDATION STATE OF SAID METAL IONS AT SAID PORTIONS WITH THE RESULT THAT SAID METLA IONS OF SAID PORTIONS OF SAID COATED SUBSTRATE SO EXPOSED TO HEAT ARE RENDERED INCAPABLE OF REDUCING SAID PRECIOUS METAL.
Claim 3
Dependent Claim
19 words
The method as set forth in claim 1 wherein said metal ions are capable of reducing said precious metal.
Claim 4
Dependent Claim
18 words
The method as set forth in claim 2 wherein said metal salt in said solution is a halide.
Claim 5
Dependent Claim
36 words
The method as set forth in claim 3 wherein said portions of said coated substrate are selectively exposed to heat so as to raise the temperature thereof to a minimum temperature on the order of 150*C.
Claim 6
Dependent Claim
58 words
The method as set forth in claim 4 including the step of immersing said substrate in a nucleating solution containing a sodium salt of a strong base and a relatively weaker acid prior to the immersion of said substrate in the solution containing a salt of a metal selected from the group consisting of tin, titanium, and lead.
Claim 7
Dependent Claim
15 words
The method as set forth in claim 5 wherein said nucleating solution comprises sodium pyrophosphate.
Claim 8
Dependent Claim
15 words
The method as set forth in claim 5 wherein said nucleating solution comprises sodium hypophosphite.
Claim 9
Dependent Claim
15 words
The method as set forth in claim 5 wherein said nucleating solution comprises sodium hydroxide.
Claim 10
Independent Claim
211 words
A method for selectively depositing a metal at least partially by electroless plating on an insulating substrate to form a metallic pattern comprising the steps of: immersing said substrate in a first solution containing a sodium salt of a strong base and a relatively weaker acid to produce a high density of nucleation sites; immersing said substrate in a second solution containing a salt of a metal selected from the group consisting of tin, titanium and lead, the oxidation state of the metal ions thereof being alterable by exposure to heat, to provide a coating of said second solution on said substrate; producing a pattern capable of reducing a precious metal from a precious metal salt by selectively exposing portions of said coated substrate to heat to effectively change the oxidation state of said metal ions at said portions with the result that said metal ions of said portions of said coated substrate so exposed to heat are rendered incapable of reducing said precious metal; immersing said substrate in a precious metal salt solution to reduce said precious metal on said pattern; and placing said precious metal pattern in an electroless plating bath which is catalyzed by said reduced precious metal to produce a selective metal deposit forming the metallic pattern.
Claim 11
Independent Claim
211 words
A method for selectively depositing a metal at least partially by electroless plating on an insulating substrate to form a metallic pattern comprising the steps of: immersing said substrate in a first solution containing a sodium salt of a strong base and a relatively weaker acid to produce a high density of nucleation sites; immersing said substrate in a second solution containing a salt of a metal selected from the group consisting of tin, titanium and lead, the oxidation state of the metal ions thereof being alterable by exposure to heat, to provide a coating of said second solution on said substrate; producing a pattern capable of reducing a precious metal from a precious metal salt by selectively exposing portions of said coated substrate to heat to effectively change the oxidation state of said metal ions at said portions with the result that said metal ions of said portions of said coated substrate so exposed to heat are rendered incapable of reducing said precious metal; immersing said substrate in a precious metal salt solution to reduce said precious metal on said pattern; and placing said precious metal pattern in an electroless plating bath which is catalyzed by said reduced precious metal to produce a selective metal deposit forming the metallic pattern.
Claim 12
Dependent Claim
15 words
A method as set forth in claim 9 wherein said metal salt is tin chloride.
Claim 13
Dependent Claim
14 words
A method as set forth in claim 10 wherein said precious metal is palladium.
Claim 14
Dependent Claim
15 words
The method as set forth in claim 11 wherein said first solution comprises sodium pyrophosphate.
Claim 15
Dependent Claim
15 words
The method as set forth in claim 11 wherein said first solution comprises sodium hypophosphite.
Claim 16
Dependent Claim
15 words
The method as set forth in claim 11 wherein said first solution comprises sodium hydroxide.
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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) | 1977-09-30 | 1978-04-01 | 1978-10-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-30 | 1982-04-01 | 1982-10-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-30 | 1986-04-01 | 1986-10-01 | $7700.00 | Window Closed / Lapsed |