US4608118A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reactive sputter etching of metal silicide structures
Assignee: Intersil Corp
•
Filing: 1985-02-15
•
Granted: 1986-08-26
•
Expires: 2005-02-15
Abstract
Abstract Polycide structures are etched with silicon tetrachloride. The etch is preferably carried out at a pressure of about 20 to 60 mtorr and overetching to remove stringers is then carried out at an increased pressure, i.e. at least about 100 mtorr. There is obtained an anisotropic etch with substantially no stringers or linewidth loss. When selectivity of etch vis-a-vis an underlying layer of gate oxide must be enhanced, from about 60 to 90 percent by volume of the silicon tetrachloride is replaced with chlorine just prior to completion of the etch.
Inventors
- 👤 Bernard J. Curtis
- 👤 Hans R. Brunner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 15:57
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/20; H10P50/26; H10P50/264; H10P50/266; H10P50/267; H10P50/268
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
59 words
A process of forming a patterned layer of a metal silicide on a substrate comprising: (a) depositing the metal silicide on the substrate; (b) providing a patterned layer of a resist material overlying the metal silicide layer; and (c) anisotropically reactive sputter etching the exposed portion of the metal silicide layer with an etchant consisting essentially of silicon tetrachloride.
Claim 2
Dependent Claim
59 words
A process of forming a patterned layer of a metal silicide on a substrate comprising: (a) depositing the metal silicide on the substrate; (b) providing a patterned layer of a resist material overlying the metal silicide layer; and (c) anisotropically reactive sputter etching the exposed portion of the metal silicide layer with an etchant consisting essentially of silicon tetrachloride.
Claim 3
Dependent Claim
14 words
A process in accordance with claim 1, wherein the metal silicide is tantalum silicide.
Claim 4
Dependent Claim
19 words
A process in accordance with claim 1, wherein the layer of metal silicide is annealed after the etching step.
Claim 5
Dependent Claim
65 words
A process of forming a patterned polycide structure on a substrate comprising: (a) providing a layer of doped silicon on the substrate; (b) depositing a layer of a metal silicide thereover; (c) providing a patterned layer of a resist material overlying the metal silicide layer; and (d) anisotropically reactive sputter etching the exposed portion of the structure with an etchant consisting essentially of silicon tetrachloride.
Claim 6
Dependent Claim
65 words
A process of forming a patterned polycide structure on a substrate comprising: (a) providing a layer of doped silicon on the substrate; (b) depositing a layer of a metal silicide thereover; (c) providing a patterned layer of a resist material overlying the metal silicide layer; and (d) anisotropically reactive sputter etching the exposed portion of the structure with an etchant consisting essentially of silicon tetrachloride.
Claim 7
Dependent Claim
22 words
A process in accordance with claim 4, wherein the structure is etched at a pressure of from about 20 to 120 millitorr.
Claim 8
Dependent Claim
22 words
A process in accordance with claim 5, wherein the structure is etched at a pressure of from about 20 to 60 millitorr.
Claim 9
Dependent Claim
38 words
A process in accordance with claim 6, wherein, after the etching of the structure is substantially complete, the pressure is increased and etching is extended for a period of time sufficient to remove stringers from the etched structure.
Claim 10
Dependent Claim
23 words
A process in accordance with claim 7, wherein said extended etch is carried out at a pressure of at least about 100 millitorr.
Claim 11
Dependent Claim
27 words
A process in accordance with claim 7, wherein said extended etch comprises from about 50 to about 150 percent of the time required to etch the structure.
Claim 12
Dependent Claim
17 words
A process in accordance with claim 4, wherein the structure is annealed prior to said etching step.
Claim 13
Dependent Claim
17 words
A process in accordance with claim 4, wherein the structure is annealed subsequent to said etching step.
Claim 14
Dependent Claim
48 words
A process in accordance with claim 4, wherein after the metal silicide layer and a major portion of the silicon layer have been etched, from about 60 to about 90 percent by volume of the silicon tetrachloride is replaced with chlorine and the etching step is thereafter completed.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-08-25 | 1990-02-24 | 1990-08-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-08-25 | 1994-02-24 | 1994-08-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-08-25 | 1998-02-24 | 1998-08-26 | $7700.00 | Window Closed / Lapsed |