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US5059243A
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Tetra aza ligand systems as complexing agents for electroless deposition of copper
Assignee: International Business Machines Corp
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Filing: 1989-04-28
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Granted: 1991-10-22
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Expires: 2009-04-28
Abstract
Abstract An electroless copper plating bath uses a series of tetradentate nitrogen ligands. The components of the bath may be substituted without extensive re-optimization of the bath. The Cu-tetra-aza ligand baths operates over a pH range between 7 and 12. Stable bath formulations employing various buffers, reducing agents and ligands have been developed. The process can be used for metal deposition at lower pH and provides the capability to use additive processing for metallization in the presence of polyimide, positive photoresist and other alkali sensitive substrates.
Inventors
- 👤 Rangarajan Jagannathan
- 👤 Randolph F. Knarr
- 👤 Mahadevaiyer Krishnan
- 👤 Gregory P. Wandy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 14:27
CPC Classifications
C; C23; C23C; C23C18/00; C23C18/16; C23C18/31; C23C18/38; C23C18/40
Claims Analysis
Total Claims: 44
Claim 1
Independent Claim
125 words
An electroless copper plating bath comprising: 4 to 15 grams per liter of a copper salt 40 to 200 mM of a tetra-aza ligand 3 to 10G/l of an amine borane 25 to 100 ml/l of a buffer, wherein said copper salt is selected from the group consisting of copper sulfate, a cetate, nitrate, and fluoroborate, said tetra-aza ligand is selected from the group consisting of 1,5,8,12 tetraazadodecane, 1,4,8,11 tetraazaundecane, 1,4,8,11 tetraazacyclotetradecane and 1,4,8,12 tetraazacyclopentadecane, said amine borane is selected from the group consisting of DMAB, morpholine borane, t-butylamineborane and pyridineborane, said buffer is selected from the group consisting of valine, Tris (hydroxymethyl), aminomethane, borax, triethanolamine, NaOH, triisopropanolamine and ethanolamine wherein the pH of the bath is in the range substantially between 7 and 12.
Claim 2
Dependent Claim
125 words
An electroless copper plating bath comprising: 4 to 15 grams per liter of a copper salt 40 to 200 mM of a tetra-aza ligand 3 to 10G/l of an amine borane 25 to 100 ml/l of a buffer, wherein said copper salt is selected from the group consisting of copper sulfate, a cetate, nitrate, and fluoroborate, said tetra-aza ligand is selected from the group consisting of 1,5,8,12 tetraazadodecane, 1,4,8,11 tetraazaundecane, 1,4,8,11 tetraazacyclotetradecane and 1,4,8,12 tetraazacyclopentadecane, said amine borane is selected from the group consisting of DMAB, morpholine borane, t-butylamineborane and pyridineborane, said buffer is selected from the group consisting of valine, Tris (hydroxymethyl), aminomethane, borax, triethanolamine, NaOH, triisopropanolamine and ethanolamine wherein the pH of the bath is in the range substantially between 7 and 12.
Claim 3
Dependent Claim
15 words
An electroless copper plating bath as set forth in claim 1, further comprising a surfactant.
Claim 4
Dependent Claim
31 words
An electroless copper plating bath as set forth in claim 2, wherein said surfactant is selected from the group consisting of sodium lauryl sulfate, FC95 surfactant and hexadecyl trimethyl ammonium hydroxide.
Claim 5
Dependent Claim
16 words
An electroless copper plating bath as set forth in claim 1 further comprising an addition agent.
Claim 6
Dependent Claim
29 words
An electroless copper plating bath as set forth in claim 4 wherein said addition agent is selected from the group consisting of 1,10 phenanthroline, 2,2 bipyridine and sodium cyanide.
Claim 7
Dependent Claim
16 words
An electroless copper plating bath as set forth in claim 2, further comprising an addition agent.
Claim 8
Dependent Claim
29 words
An electroless copper plating bath as set forth in claim 6 wherein said addition agent is selected from the group consisting of 1,10 phenanthroline, 2,2 bipyridine and sodium cyanide.
Claim 9
Dependent Claim
29 words
An electroless copper plating bath as set forth in claim 1 or 2 or 4 or 6 wherein the pH is in the range substantially between 7 and 9.
Claim 10
Dependent Claim
34 words
An electroless copper plating bath as set forth in claim 1 or 2 or 4 or 6 wherein the bath stable over at a temperature in the range between 45° C. and 70° C.
Claim 11
Dependent Claim
24 words
An electroless copper plating bath as set forth in claim 1 or 2 or 4 or 6 for providing copper deposits on a substrate.
Claim 12
Dependent Claim
19 words
An electroless copper plating bath as set forth in claim 10 wherein said substrate is an alkali sensitive substrate.
Claim 13
Dependent Claim
18 words
An electroless copper plating bath as set forth in claim 11 wherein said alkali sensitive substrate is polyimide.
Claim 14
Dependent Claim
18 words
An electroless copper plating bath as set forth in claim 11 wherein said alkali substrate includes positive photoresist.
Claim 15
Dependent Claim
23 words
An electroless copper plating bath as set forth in claim 10 wherein said substrate contains a copper seed layer on a Si/Cr substrate.
Claim 16
Dependent Claim
19 words
A electroless copper plating bath as set forth in claim 10 wherein said substrate is Pd/Sn seeded non-metallic substrate.
Claim 17
Dependent Claim
20 words
An electroless copper plating bath as set forth in claim 1, wherein the plating bath is agitated by bubbling air.
Claim 18
Dependent Claim
25 words
An electroless copper plating bath as set forth in claim 1, wherein the plating bath is agitated by bubbling a mixture of nitrogen and oxygen.
Claim 19
Dependent Claim
91 words
An electroless copper plating bath consisting of 64 mM--tetra-aza ligand 32 mM--Copper sulfate 68 mM--DMAB 10 to 50 mg/l--hexadecyl Trimethyl ammonium hydroxide 30 to 600 mg/l--2,2 Bipyridine and a sufficient quantity of buffering agent selected from the group consisting of valine, Tris (hydroxymethyl), aminomethane, borax, NaOH, triethanolamine, triisopropanolamine and ethanolamine and wherein said tetra-aza ligand is selected from the group consisting of 1,5,8,12 tetraazadodecane, 1,4,8,11 tetraazaundecane, 1,4,8,11 tetraazacyclotetradecane and 1,4,8,12 tetraazacyclopentadecane and a sufficient amount, of acid to adjust the pH to be in the range substantially between 7 and 12.
Claim 20
Dependent Claim
91 words
An electroless copper plating bath consisting of 64 mM--tetra-aza ligand 32 mM--Copper sulfate 68 mM--DMAB 10 to 50 mg/l--hexadecyl Trimethyl ammonium hydroxide 30 to 600 mg/l--2,2 Bipyridine and a sufficient quantity of buffering agent selected from the group consisting of valine, Tris (hydroxymethyl), aminomethane, borax, NaOH, triethanolamine, triisopropanolamine and ethanolamine and wherein said tetra-aza ligand is selected from the group consisting of 1,5,8,12 tetraazadodecane, 1,4,8,11 tetraazaundecane, 1,4,8,11 tetraazacyclotetradecane and 1,4,8,12 tetraazacyclopentadecane and a sufficient amount, of acid to adjust the pH to be in the range substantially between 7 and 12.
Claim 21
Dependent Claim
26 words
An electroless copper plating bath as set forth in claim 18, wherein the pH is adjusted to be in the range substantially between 7.0 to 9.0.
Claim 22
Dependent Claim
22 words
An electroless copper plating bath as set forth in claim 18, wherein said sufficient quantity of buffering agent is 50 ml/l triethanolamine.
Claim 23
Dependent Claim
22 words
An electroless copper plating bath as set forth in claim 18, wherein said sufficient quantity of buffering agent is 0.1 molar borax.
Claim 24
Dependent Claim
23 words
An electroless copper plating bath as set forth in claim 18, wherein said sufficient quantity of buffering agent is 15 g/l boric acid.
Claim 25
Dependent Claim
24 words
An electroless copper plating bath as set forth in claims 20, 21, or 22 wherein said tetra-aza ligand is 1, 5, 8, 12 tetraazadodecane.
Claim 26
Dependent Claim
24 words
An electroless copper plating bath as set forth in claims 20, 21 or 22 wherein said tetra-aza ligand is 1, 4, 8, 11 tetraazaundecane.
Claim 27
Dependent Claim
24 words
An electroless copper plating bath as set forth in claims 20, 21 or 22 wherein said tetra-aza ligand is 1, 4, 8, 11 tetraazacyclotetradecane.
Claim 28
Dependent Claim
24 words
An electroless copper plating bath as set forth in claims 20, 21 or 22 wherein said tetra-aza ligand is 1, 4, 8, 12 tetraazacyclopentadecane.
Claim 29
Dependent Claim
20 words
An electroless copper plating bath as set forth in claim 18, wherein the plating bath is agitated by bubbling air.
Claim 30
Dependent Claim
25 words
An electroless copper plating bath as set forth in claim 18, wherein the plating bath is agitated by bubbling a mixture of nitrogen and oxygen.
Claim 31
Dependent Claim
47 words
An electroless copper plating bath comprising: a copper salt; a complexing system comprising a tetra-aza ligand which forms tetra-dentate complexes with copper having high stability constants; a buffer system which when changed does not substantially affect the bath characteristics, and a reducing system comprising an amine borane.
Claim 32
Dependent Claim
47 words
An electroless copper plating bath comprising: a copper salt; a complexing system comprising a tetra-aza ligand which forms tetra-dentate complexes with copper having high stability constants; a buffer system which when changed does not substantially affect the bath characteristics, and a reducing system comprising an amine borane.
Claim 33
Dependent Claim
12 words
A bath as set forth in claim 29, further comprising a surfactant.
Claim 34
Dependent Claim
13 words
A bath as set forth in claim 29, further comprising an addition agent.
Claim 35
Dependent Claim
28 words
A bath as set forth in claim 29, wherein said copper salt is selected from the group consisting of copper sulfate, copper acetate, copper nitrate, and copper fluoroborate.
Claim 36
Dependent Claim
28 words
A bath as set forth in claim 29, wherein said complexing agent is selected from the group consisting of 1,5,8,12 tetraazadodecane, 1,4,8,11 tetraazaundecane, 1,4,8,11 tetraazacyclotetradecane, and 1,4,8,12 tetraazacyclopentadecane.
Claim 37
Dependent Claim
28 words
A bath as set forth in claim 29, wherein said buffer system is selected from the group consisting of valine, Tris(hydroxymethyl), aminomethane, borax, triethanolamine, NaOH, triisopropanolamine and ethanolamine.
Claim 38
Dependent Claim
25 words
A bath as set forth in claim 29, wherein said reducing system is selected from the group consisting of DMAB, morpholine borane, t-butylamineborane and pyridineborane.
Claim 39
Dependent Claim
84 words
A bath as set forth in claim 29, wherein said copper salt is selected from the group consisting of copper sulfate, copper acetate, copper nitrate, and copper fluoroborate, said complexing system is selected from the group consisting of 1,5,8,12 tetraazadodecane, 1,4,8,11 tetraazaundecane, 1,4,8,11 tetraazacyclotetradecane and 1,4,8,12 tetraazacyclopentadecane, said buffer system is selected from the group consisting of valine, Tris (hydroxymethyl), aminomethane, borax, triethanolamine, NaOH, triisopropanolamine and ethanolamine, and said reducing system is selected from the group consisting of DMAB, morpholine borane, t-butylamineborane and pyridineborane.
Claim 40
Dependent Claim
20 words
A bath as set forth in claim 29, wherein the pH is in the range substantially between 7 and 12.
Claim 41
Dependent Claim
20 words
A bath as set forth in claim 37, wherein the pH is in the range substantially between 7 and 9.
Claim 42
Dependent Claim
29 words
A bath as set forth in claim 29, wherein said buffer system provides a stable bath over a temperature range between approximately 45 degrees C. and 70 degrees C.
Claim 43
Dependent Claim
28 words
A bath as set forth in claim 30, wherein said surfactant is selected from the group consisting of sodium lauryl sulfate, FC 95 surfactant, and hexadecyl trimethylammonium hydroxide.
Claim 44
Dependent Claim
26 words
A bath as set forth in claim 31, wherein said addition agent is selected from the group consisting of 1,10 phenanthroline, 2,2 bipyridine, and sodium cyanide.
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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) | 1994-10-21 | 1995-04-22 | 1995-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-10-21 | 1999-04-22 | 1999-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-10-21 | 2003-04-22 | 2003-10-22 | $7700.00 | Window Closed / Lapsed |