US4686002A
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Stabilized choline base solutions
Assignee: EKC Technology Inc
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Filing: 1986-07-18
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Granted: 1987-08-11
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Expires: 2006-07-18
Abstract
Abstract Solutions of choline base, (2-hydroxyethyl)trimethylammonium hydroxide, in water and/or lower alkanols may be stabilized by the addition of a stabilizing concentration of formaldehyde or paraformaldehyde. The stabilized solutions may be used as cleaning solutions, etchants for semiconductors and metal layers, and developers and strippers for positive working photoresists, and for other uses where a metal ion-free base is desired.
Inventors
- 👤 Carl J. Tasset
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:41
CPC Classifications
H; H10; H10P; H10P70/00; H10P70/10; H10P70/15; C; C11; C11D; C11D7/00; C11D7/22; C11D7/32; C11D7/3209; C11D7/3218; C23; C23F; C23F1/00; C23F1/10; C23F1/14; C23F1/32; G; G03; G03F; G03F7/00; G03F7/26; G03F7/30; G03F7/32; G03F7/42; G03F7/422; G03F7/425; H10P50/00; H10P50/60; H10P50/66; H10P50/663; H10P50/667
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
41 words
A stabilized choline base solution comprising choline base; a solvent selected from the group consisting of water, lower alkanols, and mixtures thereof; and a stabilizing concentration of a stabilizer selected from the group consisting of formaldehyde, paraformaldehyde, and a mixture thereof.
Claim 2
Dependent Claim
41 words
A stabilized choline base solution comprising choline base; a solvent selected from the group consisting of water, lower alkanols, and mixtures thereof; and a stabilizing concentration of a stabilizer selected from the group consisting of formaldehyde, paraformaldehyde, and a mixture thereof.
Claim 3
Dependent Claim
22 words
The solution of claim 1 wherein the concentration of choline base is between about 1% and 60% by weight of the solution.
Claim 4
Dependent Claim
21 words
The solution of claim 2 wherein the concentration of choline base is at least about 10% by weight of the solution.
Claim 5
Dependent Claim
10 words
The solution of claim 1 wherein the solvent is water.
Claim 6
Dependent Claim
19 words
The solution of claim 4 wherein the concentration of choline base is between about 10% and 40% by weight.
Claim 7
Dependent Claim
12 words
The solution of claim 3 wherein the solvent is a lower alkanol.
Claim 8
Dependent Claim
10 words
The solution of claim 6 wherein the solvent is methanol.
Claim 9
Dependent Claim
19 words
The solution of claim 7 wherein the concentration of choline base is between about 10% and 50% by weight.
Claim 10
Dependent Claim
17 words
The solution of claim 1 wherein the solvent is a mixture of water and a lower alkanol.
Claim 11
Dependent Claim
15 words
The solution of claim 9 wherein the solvent is a mixture of water and methanol.
Claim 12
Dependent Claim
19 words
The solution of claim 10 wherein the concentration of choline base is between about 10% and 50% by weight.
Claim 13
Dependent Claim
12 words
The solution of claim 1 wherein the stabilizer consists essentially of formaldehyde.
Claim 14
Dependent Claim
22 words
The solution of claim 12 wherein the concentration of stabilizer is between about 0.2% and 20% by weight of the choline base.
Claim 15
Dependent Claim
22 words
The solution of claim 13 wherein the concentration of stabilizer is between about 0.5% and 10% by weight of the choline base.
Claim 16
Dependent Claim
12 words
The solution of claim 1 wherein the stabilizer consists essentially of paraformaldehyde.
Claim 17
Dependent Claim
22 words
The solution of claim 15 wherein the concentration of stabilizer is between about 0.2% and 20% by weight of the choline base.
Claim 18
Dependent Claim
22 words
The solution of claim 16 wherein the concentration of stabilizer is between about 0.5% and 10% by weight of the choline base.
Claim 19
Dependent Claim
12 words
The solution of claim 1 which is substantially free of metal ions.
Claim 20
Independent Claim
87 words
A method of removing a photoresist film from a substrate which comprises contacting a substrate having a positive-working photoresist film thereon with a solution at a temperature and for a time sufficient to remove at least a portion of the photoresist film from the substrate, the solution comprising an effective amount of choline base; a solvent selected from the group consisting of water, lower alkanols, and mixtures thereof; and a stabilizing concentration of a stabilizer selected from the group consisting of formaldehyde, paraformaldehyde, and a mixture thereof.
Claim 21
Independent Claim
87 words
A method of removing a photoresist film from a substrate which comprises contacting a substrate having a positive-working photoresist film thereon with a solution at a temperature and for a time sufficient to remove at least a portion of the photoresist film from the substrate, the solution comprising an effective amount of choline base; a solvent selected from the group consisting of water, lower alkanols, and mixtures thereof; and a stabilizing concentration of a stabilizer selected from the group consisting of formaldehyde, paraformaldehyde, and a mixture thereof.
Claim 22
Independent Claim
107 words
A method of etching a metal layer in the surface of an intermediate product obtained in the manufacture of a semiconductor device which comprises contacting the surface of an intermediate product obtained in the manufacture of a semiconductor device having a metal layer thereon with a solution at a temperature and for a time sufficient to etch at least a portion of the metal layer, the solution comprising an effective amount of choline base; a solvent selected from the group consisting of water, lower alkanols, and mixtures thereof; and a stabilizing concentration of a stabilizer selected from the group consisting of formaldehyde, paraformaldehyde, and a mixture thereof.
Claim 23
Independent Claim
107 words
A method of etching a metal layer in the surface of an intermediate product obtained in the manufacture of a semiconductor device which comprises contacting the surface of an intermediate product obtained in the manufacture of a semiconductor device having a metal layer thereon with a solution at a temperature and for a time sufficient to etch at least a portion of the metal layer, the solution comprising an effective amount of choline base; a solvent selected from the group consisting of water, lower alkanols, and mixtures thereof; and a stabilizing concentration of a stabilizer selected from the group consisting of formaldehyde, paraformaldehyde, and a mixture thereof.
Claim 24
Independent Claim
77 words
A method of cleaning the surface of an substrate which comprises contacting the surface of the substrate with a solution at a temperature and for a time sufficient to clean the surface of the substrate, the solution comprising an effective amount of choline base; a solvent selected from the group consisting of water, lower alkanols, and mixtures thereof; and a stabilizing concentration of a stabilizer selected from the group consisting of formaldehyde, paraformaldehyde, and a mixture thereof.
Claim 25
Independent Claim
77 words
A method of cleaning the surface of an substrate which comprises contacting the surface of the substrate with a solution at a temperature and for a time sufficient to clean the surface of the substrate, the solution comprising an effective amount of choline base; a solvent selected from the group consisting of water, lower alkanols, and mixtures thereof; and a stabilizing concentration of a stabilizer selected from the group consisting of formaldehyde, paraformaldehyde, and a mixture thereof.
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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) | 1990-08-10 | 1991-02-09 | 1991-08-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-08-10 | 1995-02-09 | 1995-08-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-08-10 | 1999-02-09 | 1999-08-11 | $7700.00 | Window Closed / Lapsed |