US5407788A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photoresist stripping method
Assignee: AT&T Inc
•
Filing: 1993-06-24
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Granted: 1995-04-18
•
Expires: 2013-06-24
Abstract
Abstract The solubility of tetramethylammonium hydroxide pentahydrate in dimethyl sulfoxide is significantly increased by adding to the solution a quantity of dipropyleneglycol monomethylether. This permits up to twelve percent of the tetramethylammonium hydroxide pentahydrate to be dissolved in dimethyl sulfoxide, rather than the maximum of two percent that would otherwise be the case, which enhances the capacity of the solution to strip photoresist. Particularly, if the concentration of dipropyleneglycol monomethylether is in the range of ten to thirty percent, one can obtain both a high stripping rate and a much higher stripping capacity. For example, stripping capacity may be increased from one hundred forty substrates per gallon to six hundred substrates per gallon.
Inventors
- 👤 Treliant Fang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 07:43
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/26; G03F7/42; G03F7/422; G03F7/425
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
110 words
An improved method for making an electronic device comprising the steps of: coating part of a substrate with a photoresist coating; selectively exposing the photoresist to actinic light; developing the photoresist coating in accordance with said selective exposure to actinic radiation; using the developed photoresist coating as a mask to permit selective operation on part of the underlying substrate; and removing the developed photoresist coating by exposing the coating to a solution comprising tetramethylammonium hydroxide and dimethyl sulfoxide; wherein the improvement comprises: including dipropyleneglycol monomethylether in said solution; and increasing the proportion of tetramethylammonium hydroxide in the solution beyond that which could be dissolved in the absence of dipropyleneglycol monomethylether.
Claim 2
Dependent Claim
110 words
An improved method for making an electronic device comprising the steps of: coating part of a substrate with a photoresist coating; selectively exposing the photoresist to actinic light; developing the photoresist coating in accordance with said selective exposure to actinic radiation; using the developed photoresist coating as a mask to permit selective operation on part of the underlying substrate; and removing the developed photoresist coating by exposing the coating to a solution comprising tetramethylammonium hydroxide and dimethyl sulfoxide; wherein the improvement comprises: including dipropyleneglycol monomethylether in said solution; and increasing the proportion of tetramethylammonium hydroxide in the solution beyond that which could be dissolved in the absence of dipropyleneglycol monomethylether.
Claim 3
Dependent Claim
12 words
The method of claim 1 wherein: the photoresist is an electrophoretic photoresist.
Claim 4
Dependent Claim
25 words
The method of claim 1 wherein: the substrate comprises a metal coating on a solid body; and the photoresist is coated on the metal layer.
Claim 5
Dependent Claim
23 words
The method of claim 3 wherein: the step of selectively operating on the substrate comprises the step of selectively etching said metal coating.
Claim 6
Dependent Claim
14 words
The method of claim 4 wherein: the upper surface of the metal comprises titanium.
Claim 7
Dependent Claim
15 words
The method of claim 4 wherein: the solution contains ten to thirty percent dipropyleneglycol monomethylether.
Claim 8
Dependent Claim
15 words
The method of claim 1 wherein: the solution contains ten to thirty percent dipropyleneglycol monomethylether.
Claim 9
Dependent Claim
12 words
The method of claim 7 wherein: the photoresist is an electrophoretic photoresist.
Claim 10
Dependent Claim
15 words
The method of claim 8 wherein: the electrophoretic photoresist is coated on a metal layer.
Claim 11
Dependent Claim
15 words
The method of claim 9 wherein: the metal layer is coated on a polymer layer.
Claim 12
Dependent Claim
21 words
The method of claim 10 wherein: the polymer layer is a triazine-based polymer and the photoresist is a polymethyl methacrylate-based polymer.
Claim 13
Dependent Claim
47 words
The method of claim 11 wherein: the metal layer comprises a lower layer of titanium, a middle layer of copper, and an upper layer of titanium, the lower titanium layer being coated on the polymer layer, and the electrophoretic photoresist being coated on the upper titanium layer.
Claim 14
Dependent Claim
15 words
The method of claim 1 wherein: the solution contains fifteen to twenty-seven percent dipropyleneglycol monomethylether.
Claim 15
Dependent Claim
19 words
The method of claim 1 wherein: the tetramethylammonium hydroxide is added to the solution by adding tetramethylammonium hydroxide pentahydrate.
Claim 16
Dependent Claim
25 words
The method of claim 14 wherein: the solution contains ten to thirty percent tetramethylammonium hydroxide dipropyleneglycol monomethylether and two to twelve percent tetramethylammonium hydroxide pentahydrate.
Claim 17
Dependent Claim
25 words
The method of claim 14 wherein: the solution consists of about 9.7% tetramethylammonium hydroxide pentahydrate, about twenty-one percent dipropyleneglycol monomethylether and about 69.3% dimethyl sulfoxide.
References Cited (Backward Citations)
US4518675A
Cited
JPS61163342A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-04-17 | 1998-10-17 | 1999-04-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-04-17 | 2002-10-17 | 2003-04-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-04-17 | 2006-10-17 | 2007-04-18 | $7700.00 | Window Closed / Lapsed |