US4741799A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Anisotropic silicon etching in fluorinated plasma
Assignee: International Business Machines Corp
•
Filing: 1986-11-17
•
Granted: 1988-05-03
•
Expires: 2006-11-17
Abstract
Abstract A method of high rate anisotropic etching of silicon in a high pressure plasma is described. In one embodiment the etching ambient is a mixture of either NF 3 or SF 6 , an inert gas such as nitrogen, and a polymerizing gas such as CHF 3 that creates conditions necessary for anisotropy not normally possible with nonpolymerizing fluorinated gases in a high pressure regime. The etch process is characterized by high etch rates and good uniformity utilizing photoresist or similar materials as a mask. The present process may advantageously be used to etch deep trenches in silicon using a photoresist mask.
Inventors
- 👤 Lee Chen
- 👤 Gangadhara S. Mathad
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:59
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/20; H10P50/24; H10P50/242
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
68 words
A mehtod of anisotropically etching a silicon body in a single etching step, comprising: placing said silicon body in a gaseous plasma environment at a constant gas pressure and composition consisting essentially of a chlorine-free fluorine-containing etchant gas, and a polymer-forming gas for substantially limiting lateral etching of said silicon body, said polymer-forming gas consisting of one or more halogenated hydrocarbons wherein the halogen in each is fluorine.
Claim 2
Dependent Claim
68 words
A mehtod of anisotropically etching a silicon body in a single etching step, comprising: placing said silicon body in a gaseous plasma environment at a constant gas pressure and composition consisting essentially of a chlorine-free fluorine-containing etchant gas, and a polymer-forming gas for substantially limiting lateral etching of said silicon body, said polymer-forming gas consisting of one or more halogenated hydrocarbons wherein the halogen in each is fluorine.
Claim 3
Dependent Claim
25 words
The method of claim 1, wherein said etchant gas is selected from the group consisting of NF 3 , SF 6 and the combination thereof.
Claim 4
Dependent Claim
13 words
The method of claim 1, wherein said polymer-forming gas comprises CHF 3 .
Claim 5
Dependent Claim
33 words
The method of claim 1, wherein said gaseous plasma environment comprises a pressure of about 1-5 torr and a power density of about 2-5 watts/cm 2 at the surface of said silicon body.
Claim 6
Dependent Claim
26 words
The method of claim 1, wherein said silicon body to be etched comprises multiple layers of differently doped monocrystalline silicon or polycrystalline silicon or combinations thereof.
Claim 7
Independent Claim
72 words
A method of anisotropically etching a silicon body in a single etching step, comprising: placing said silicon body in a gaseous plasma environment at a constant gas pressure and composition consisting essentially of an inert gas, and a chlorine-free fluorine-containing etchant gas, and a polymer-forming gas for substantially limiting lateral etching of said silicon body, said polymer-forming gas consisting of one or more halogenated hydrocarbons wherein the halogen in each is fluorine.
Claim 8
Independent Claim
72 words
A method of anisotropically etching a silicon body in a single etching step, comprising: placing said silicon body in a gaseous plasma environment at a constant gas pressure and composition consisting essentially of an inert gas, and a chlorine-free fluorine-containing etchant gas, and a polymer-forming gas for substantially limiting lateral etching of said silicon body, said polymer-forming gas consisting of one or more halogenated hydrocarbons wherein the halogen in each is fluorine.
Claim 9
Dependent Claim
11 words
The method of claim 6, wherein said inert gas comprises nitrogen.
References Cited (Backward Citations)
US4473435A
Cited
US4529475A
Cited
US4431477A
Cited
US4522681A
Cited
US4534816A
Cited
US4528066A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-05-03 | 1991-11-02 | 1992-05-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-05-03 | 1995-11-02 | 1996-05-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-05-03 | 1999-11-02 | 2000-05-03 | $7700.00 | Window Closed / Lapsed |