US4941941A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of anisotropically etching silicon wafers and wafer etching solution
Assignee: International Business Machines Corp
•
Filing: 1989-10-03
•
Granted: 1990-07-17
•
Expires: 2009-10-03
Abstract
Abstract An improved method for anisotropically etching the (100) crystallographic plane of silicon wafers, involves immersing the wafers in an etching solution containing an aromatic compound having at least two adjacent hydroxyl groups and a polar functional group on the ring, an amine and water. A quality etch at an appreciably greater rate is achieved.
Inventors
- 👤 Larry W. Austin
- 👤 Harold G. Linde
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 19:28
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/60; H10P50/64; H10P50/642; H10P90/00; H10P90/12; H10P90/126; H10P50/644
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
37 words
A method of etching silicon, comprising contacting said silicon with an etching solution which comprises an aromatic compound having at least two adjacent hydroxyl groups and a polar functional group on the ring, an amine and water.
Claim 2
Independent Claim
37 words
A method of etching silicon, comprising contacting said silicon with an etching solution which comprises an aromatic compound having at least two adjacent hydroxyl groups and a polar functional group on the ring, an amine and water.
Claim 3
Dependent Claim
12 words
The method of claim 1, wherein said polar functional group is COOH.
Claim 4
Dependent Claim
12 words
The method of claim 2, wherein said aromatic compound is gallic acid.
Claim 5
Dependent Claim
33 words
The method of claim 1, wherein said amine is selected from the group consisting of a diamine having 2-4 carbon atoms and an alkanolamine in which each alkanol group contains 2-3 carbon atoms.
Claim 6
Dependent Claim
10 words
The method of claim 4, wherein said amine is monoethanolamine.
Claim 7
Dependent Claim
14 words
The method of claim 1, wherein said etching solution further comprises pyrazine or piperidine.
Claim 8
Dependent Claim
14 words
The method of claim 1, wherein hydrogen peroxide is added to said etching solution.
Claim 9
Dependent Claim
14 words
The method of claim 1, wherein a surfactant is added to said etching solution.
Claim 10
Dependent Claim
32 words
The method of claim 1, wherein said etching solution comprises about 4-6 mole percent of said aromatic compound, about 39-56 mole percent of said amine and about 57-38 mole percent of water.
Claim 11
Dependent Claim
23 words
The method of claim 1, wherein said etching solution has a temperature of about 115°-125° C. and has a pH of about 11-12.
Claim 12
Independent Claim
77 words
A method of etching a silicon wafer, comprising introducing said wafer into an etching solution which comprises about 4-6 mole percent of an aromatic compound having at least two adjacent hydroxyl groups and a COOH group on the ring, about 39-56 mole percent of an amine selected from the group consisting of a diamine having 2-4 carbon atoms and an alkanolamine in which each alkanol group contains 2-3 carbon atoms and about 57-38 mole percent of water.
Claim 13
Independent Claim
77 words
A method of etching a silicon wafer, comprising introducing said wafer into an etching solution which comprises about 4-6 mole percent of an aromatic compound having at least two adjacent hydroxyl groups and a COOH group on the ring, about 39-56 mole percent of an amine selected from the group consisting of a diamine having 2-4 carbon atoms and an alkanolamine in which each alkanol group contains 2-3 carbon atoms and about 57-38 mole percent of water.
Claim 14
Dependent Claim
17 words
The method of claim 11, wherein said aromatic compound is gallic acid and said amine is monoethanolamine.
Claim 15
Dependent Claim
23 words
The method of claim 12, wherein said etching solution has a temperature of about 115°-125° C. and has a pH of about 11-12.
Claim 16
Dependent Claim
14 words
The method of claim 13, wherein said etching solution further comprises pyrazine or piperidine.
Claim 17
Dependent Claim
14 words
The method of claim 14, wherein hydrogen peroxide is added to said etching solution.
Claim 18
Dependent Claim
14 words
The method of claim 15, wherein a surfactant is added to said etching solution.
Claim 19
Dependent Claim
28 words
An etching solution for silicon, comprising an aromatic compound having at least two adjacent hydroxyl groups and a polar functional group on the ring, an amine and water.
Claim 20
Dependent Claim
28 words
An etching solution for silicon, comprising an aromatic compound having at least two adjacent hydroxyl groups and a polar functional group on the ring, an amine and water.
Claim 21
Dependent Claim
13 words
The etching solution of claim 17, wherein said polar functional group is COOH.
Claim 22
Dependent Claim
13 words
The etching solution of claim 18, wherein said aromatic compound is gallic acid.
Claim 23
Dependent Claim
34 words
The etching solution of claim 17, wherein said amine is selected from the group consisting of a diamine having 2-4 carbon atoms and an alkanolamine in which each alkanol group contains 2-3 carbon atoms.
Claim 24
Dependent Claim
11 words
The etching solution of claim 20, wherein said amine is monoethanolamine.
Claim 25
Dependent Claim
11 words
The etching solution of claim 17, further comprising pyrazine or piperidine.
Claim 26
Dependent Claim
10 words
The etching solution of claim 17, further comprising a surfactant.
Claim 27
Dependent Claim
29 words
The etching solution of claim 17, comprising about 4-6 mole percent of said aromatic compound, about 39-56 mole percent of said amine and about 57-38 mole percent of water.
Claim 28
Dependent Claim
66 words
An etching solution for silicon, comprising about 4-6 mole percent of an aromatic compound having at least two adjacent hydroxyl groups and a COOH group on the ring, about 39-56 mole percent of an amine selected from the group consisting of a diamine having 2-4 carbon atoms and an alkanolamine in which each alkanol group contains 2-3 carbon atoms and about 57-38 mole percent of water.
Claim 29
Dependent Claim
66 words
An etching solution for silicon, comprising about 4-6 mole percent of an aromatic compound having at least two adjacent hydroxyl groups and a COOH group on the ring, about 39-56 mole percent of an amine selected from the group consisting of a diamine having 2-4 carbon atoms and an alkanolamine in which each alkanol group contains 2-3 carbon atoms and about 57-38 mole percent of water.
Claim 30
Dependent Claim
18 words
The etching solution of claim 25, wherein said aromatic compound is gallic acid and said amine is monoethanolamine.
Claim 31
Dependent Claim
11 words
The etching solution of claim 26, further comprising pyrazine or piperidine.
Claim 32
Dependent Claim
10 words
The etching solution of claim 27, further comprising a surfactant.
References Cited (Backward Citations)
US3160539A
Cited
US3650957A
Cited
US3873203A
Cited
US4229979A
Cited
US4293373A
Cited
US4342817A
Cited
US4417946A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-07-16 | 1994-01-15 | 1994-07-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-07-16 | 1998-01-15 | 1998-07-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-07-16 | 2002-01-15 | 2002-07-17 | $7700.00 | Window Closed / Lapsed |