US4943344A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Etching method
Assignee: Renesas Technology Corp
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Filing: 1989-06-06
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Granted: 1990-07-24
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Expires: 2009-06-06
Abstract
Abstract A deep trench is formed by carrying out etching by using an etching gas free of carbon and silicon, which contains at least one member selected from the group consisting of fluorine, chlorine and bromine, while maintaining an article to be etched at such a temperature that the reaction probability between silicon and fluorine, chlorine or bromine contained in the etching gas is less than 1/10 of the reaction probability at 20° C. According to this method, a deep trench having a very narrow width and a large aspect ratio, which cannot be formed according to the conventional method, can be formed very promptly with much reduced side etching.
Inventors
- 👤 Shinichi Tachi
- 👤 Kazunori Tsujimoto
- 👤 Sadayuki Okudaira
- 👤 Kiichiro Mukai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:11
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/20; H10P50/24; H10P50/242
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
160 words
An etching method for etching a single crystal silicon substrate, comprising: providing an organic film as an etching mask on the silicon substrate, having at least one opening which exposes at least one portion of the silicon substrate, etching at least one exposed portion with a plasma of an etching gas and forming at least one trench on the silicon substrate by continued etching of the at least one exposed portion, wherein the etching gas contains neither carbon nor silicon but is sulphur hexafloride (SF 6 ), and wherein etching is carried out while the silicon substrate is maintained at a temperature lower than -100° C. so that the reaction probability between the fluorine which is contained in the plasma and the surface atoms of the silicon substrate is less than 1/10 of the reaction probability at 20° C., thereby achieving a high selection ratio of etching speed of said silicon substrate to etching speed of said organic resist film.
Claim 2
Dependent Claim
160 words
An etching method for etching a single crystal silicon substrate, comprising: providing an organic film as an etching mask on the silicon substrate, having at least one opening which exposes at least one portion of the silicon substrate, etching at least one exposed portion with a plasma of an etching gas and forming at least one trench on the silicon substrate by continued etching of the at least one exposed portion, wherein the etching gas contains neither carbon nor silicon but is sulphur hexafloride (SF 6 ), and wherein etching is carried out while the silicon substrate is maintained at a temperature lower than -100° C. so that the reaction probability between the fluorine which is contained in the plasma and the surface atoms of the silicon substrate is less than 1/10 of the reaction probability at 20° C., thereby achieving a high selection ratio of etching speed of said silicon substrate to etching speed of said organic resist film.
Claim 3
Dependent Claim
24 words
An etching method according to claim 1, wherein said at least one trench has an opening having a width not larger than 1.0 μm.
Claim 4
Dependent Claim
31 words
An etching method according to claim 1, wherein a difference between a width of said trench and a width of said at least one opening is not larger than 0.1 μm.
Claim 5
Dependent Claim
120 words
An etching method for etching a silicon substrate, comprising: etching at least one exposed portion of the silicon substrate by contacting the at least one exposed portion with a plasma of an etching gas and forming at least one trench on the silicon substrate by continued etching of the at least one exposed portion, wherein the etching gas contains neither carbon nor silicon but is a chlorine-containing gas, and wherein etching is carried out while the silicon substrate is maintained at a temperature lower than -40° C. so that the reaction probability between the chlorine which is contained in the plasma and the surface atoms of the silicon substrate is less than 1/10 of the reaction probability at 20° C.
Claim 6
Dependent Claim
120 words
An etching method for etching a silicon substrate, comprising: etching at least one exposed portion of the silicon substrate by contacting the at least one exposed portion with a plasma of an etching gas and forming at least one trench on the silicon substrate by continued etching of the at least one exposed portion, wherein the etching gas contains neither carbon nor silicon but is a chlorine-containing gas, and wherein etching is carried out while the silicon substrate is maintained at a temperature lower than -40° C. so that the reaction probability between the chlorine which is contained in the plasma and the surface atoms of the silicon substrate is less than 1/10 of the reaction probability at 20° C.
Claim 7
Dependent Claim
15 words
An etching method according to claim 4, wherein the chlorine-containing gas is Cl 2 .
Claim 8
Dependent Claim
120 words
An etching method for etching a silicon substrate, comprising: etching at least one exposed portion of the silicon substrate by contacting the at least one exposed portion with a plasma of an etching gas and forming at least one trench on the silicon substrate by continued etching of the at least one exposed portion, wherein the etching gas contains neither carbon nor silicon but is a bromine-containing gas, and wherein etching is carried out while the silicon substrate is maintained at a temperature lower than -10° C. so that the reaction probability between the bromine which is contained in the plasma and the surface atoms of the silicon substrate is less than 1/10 of the reaction probability at 20° C.
Claim 9
Dependent Claim
120 words
An etching method for etching a silicon substrate, comprising: etching at least one exposed portion of the silicon substrate by contacting the at least one exposed portion with a plasma of an etching gas and forming at least one trench on the silicon substrate by continued etching of the at least one exposed portion, wherein the etching gas contains neither carbon nor silicon but is a bromine-containing gas, and wherein etching is carried out while the silicon substrate is maintained at a temperature lower than -10° C. so that the reaction probability between the bromine which is contained in the plasma and the surface atoms of the silicon substrate is less than 1/10 of the reaction probability at 20° C.
Claim 10
Dependent Claim
15 words
An etching method according to claim 6, wherein the bromine-containing gas is Br 2 .
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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) | 1993-07-23 | 1994-01-22 | 1994-07-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-07-23 | 1998-01-22 | 1998-07-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-07-23 | 2002-01-22 | 2002-07-24 | $7700.00 | Window Closed / Lapsed |