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US5658472A
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Method for producing deep vertical structures in silicon substrates
Assignee: International Business Machines Corp
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Filing: 1995-06-07
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Granted: 1997-08-19
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Expires: 2015-06-07
Abstract
Abstract A method is provided for producing deep substantially vertical structures in silicon substrates, wherein in a first step, the silicon substrate is anisotropically plasma etched to a first predetermined depth, thereby creating a first structure. Subsequently, the surface of the substrate is covered conformally with an etch-resistant coating, and the horizontal parts of said coating are selectively removed. Following this removal, the substrate is anisotropically plasma etched at low temperatures to a second predetermined depth with a mixture of SF 6 /O 2 , whereby a second structure is created. Finally, the vertical parts of the coating are removed.
Inventors
- 👤 Johann Bartha
- 👤 Johann Greschner
- 👤 Robert Junginger
- 👤 Georg Kraus
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 19:49
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/20; H10P50/24; H10P50/242; H10P50/244; H10P50/69; H10P50/691; H10P50/692
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
100 words
A method for producing deep substantially vertical structures in silicon substrates, comprising the steps of a) anisotropically plasma etching a portion of the silicon substrate to a first depth, b) conformally coating the surface of said silicon substrate and said anisotropically etched portion with an etch-resistant coating, c) selectively removing the horizontal parts of said coating, d) anisotropically plasma etching said anisotropically etched portion of said silicon substrate at low temperatures to a second depth with a mixture of SF 6 /O 2 , and e) removing the vertical parts of said coating, thereby forming a deep substantially vertical structure.
Claim 2
Independent Claim
100 words
A method for producing deep substantially vertical structures in silicon substrates, comprising the steps of a) anisotropically plasma etching a portion of the silicon substrate to a first depth, b) conformally coating the surface of said silicon substrate and said anisotropically etched portion with an etch-resistant coating, c) selectively removing the horizontal parts of said coating, d) anisotropically plasma etching said anisotropically etched portion of said silicon substrate at low temperatures to a second depth with a mixture of SF 6 /O 2 , and e) removing the vertical parts of said coating, thereby forming a deep substantially vertical structure.
Claim 3
Dependent Claim
36 words
The method according to claim 1 wherein said mixture of SF 6 /O 2 contains 5% to 30% O 2 and 95 to 70% SF 6 , preferably 20% O 2 and 80% SF 6 .
Claim 4
Dependent Claim
30 words
The method according to claim 1, wherein the temperature of the etching in step d) is in the range between -80° C. and -120° C., and especially is -100° C.
Claim 5
Dependent Claim
37 words
The method according to claim 1 wherein said etching in step a) is performed for 10 minutes using a microwave power of 1500 W, and a substrate bias of -25 V at a pressure of 1 Pa.
Claim 6
Dependent Claim
28 words
The method according to claim 1, wherein the etching in step a) is performed by RIE or by using a gas mixture of SF 6 /O 2 .
Claim 7
Dependent Claim
15 words
The method according to claim 1, wherein said etch-resistant coating consists of an ice film.
Claim 8
Dependent Claim
15 words
The method according to claim 1, wherein said etch-resistant coating is a thermal oxide coating.
Claim 9
Dependent Claim
23 words
The method according to claim 6, wherein the ice film is applied by condensing water vapor on the surface of the first structure.
Claim 10
Dependent Claim
17 words
The method according to claim 8, wherein the water partial pressure is between 0.1 and 0.5 Pa.
Claim 11
Dependent Claim
21 words
The method according to claim 6, wherein the horizontal parts of the ice film are removed by sputter etching with argon.
Claim 12
Dependent Claim
19 words
The method according to claim 1, wherein the step of conformally coating is controlled by means of an interferometer.
Claim 13
Dependent Claim
18 words
The method according to claim 10, wherein the step of removing is controlled my means of an interferometer.
Claim 14
Dependent Claim
47 words
The method according to claim 1, wherein the thickness of said coating on the horizontal parts of the substrate is between 1 and 1.5 micrometers and wherein the thickness of said coating on the vertical parts is half the thickness of said coating on the horizontal parts.
Claim 15
Dependent Claim
37 words
The method according to claim 10, wherein said sputter etching is performed with an argon flow of 20 sccm, a reactor pressure of 0.4 Pa, a microwave power of 1500 W and a DC-bias of -200 V.
Claim 16
Dependent Claim
20 words
The method according to claim 1, wherein the first depth is 10 to 50 μm, preferably 20 to 40 μm.
Claim 17
Dependent Claim
19 words
The method according to claim 1, wherein the second depth is about 30 to 90 μm, preferably 50 μm.
Claim 18
Dependent Claim
14 words
The method according to claim 1, wherein steps a) to e) are performed repeatedly.
Claim 19
Dependent Claim
18 words
The method according to claim 1, wherein said silicon substrate is a guide plate for a test probe.
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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) | 2000-08-18 | 2001-02-17 | 2001-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-08-18 | 2005-02-17 | 2005-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-08-18 | 2009-02-17 | 2009-08-19 | $7700.00 | Window Closed / Lapsed |