US4646424A
Expired / Lapsed
US
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Deposition and hardening of titanium gate electrode material for use in inverted thin film field effect transistors
Assignee: General Electric Co
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Filing: 1985-08-02
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Granted: 1987-03-03
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Expires: 2005-08-02
Abstract
Abstract The gate electrode in an inverted field effect transistor (FET) is fabricated with titanium to provide an FET which is particularly suitable for use as the switching element in a matrix addressed liquid crystal display. More particularly, the resist employed in gate electrode patterning is plasma ashed in an oxygen atmosphere to toughen the titanium gate material and render it more amenable to subsequent processing steps.
Inventors
- 👤 Harold G. Parks
- 👤 George E. Possin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 22:25
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/031; H10D30/0312; H10D30/0316; G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/136; G02F1/1362; G02F1/1368; H10D30/0321; H10D30/60; H10D30/67; H10D30/6729; H10D30/6737; H10D30/6739; Y; Y10; Y10S; Y10S148/00; Y10S148/131
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
96 words
A method for deposition of gate electrode material in an inverted thin film field effect transistor, said method comprising the steps of: disposing a layer of silicon oxide on an insulative substrate; disposing a layer of titanium over said silicon oxide layer; coating said titanium layer with a positive photoresist; exposing said photoresist through a desired pattern mask to create a pattern of exposed resist material; developing said resist layer; plasma etching said titanium beneath said exposed resist; plasma ashing at least some of the remaining resist in an oxygen atmosphere; and stripping any remaining resist.
Claim 2
Independent Claim
96 words
A method for deposition of gate electrode material in an inverted thin film field effect transistor, said method comprising the steps of: disposing a layer of silicon oxide on an insulative substrate; disposing a layer of titanium over said silicon oxide layer; coating said titanium layer with a positive photoresist; exposing said photoresist through a desired pattern mask to create a pattern of exposed resist material; developing said resist layer; plasma etching said titanium beneath said exposed resist; plasma ashing at least some of the remaining resist in an oxygen atmosphere; and stripping any remaining resist.
Claim 3
Dependent Claim
15 words
The method of claim 1 in which the silicon oxide is disposed by sputter deposition.
Claim 4
Dependent Claim
19 words
The method of claim 1 in which said silicon oxide is disposed to a thickness of approximately 1,200 Angstroms.
Claim 5
Dependent Claim
12 words
The method of claim 1 in which said insulative substrate comprises glass.
Claim 6
Dependent Claim
21 words
The method of claim 1 in which said silicon oxide disposition includes cleaning said substrate prior to deposition of said oxide.
Claim 7
Dependent Claim
15 words
The method of claim 1 in which said titanium is deposed by electron beam evaporation.
Claim 8
Dependent Claim
18 words
The method of claim 1 in which said titanium is disposed to a thickness of approximately 800 Angstroms.
Claim 9
Dependent Claim
16 words
The method of claim 1 further including cleaning said substrate after deposition of said silicon oxide.
Claim 10
Dependent Claim
19 words
The method of claim 1 further including the step of cleaning said substrate after deposition of said titanium layer.
Claim 11
Dependent Claim
22 words
The method of claim 1 in which the plasma etching of said titanium occurs in an atmosphere of carbon tetrafluoride and oxygen.
Claim 12
Dependent Claim
16 words
The method of claim 10 in which said oxygen comprises 4% by volume of said atmosphere.
Claim 13
Dependent Claim
21 words
The method of claim 1 in which said plasma ashing occurs at temperatures from about 80° C. to about 150° C.
Claim 14
Dependent Claim
20 words
The method of claim 1 in which said plasma ashing occurs at pressures from about 0.1 to about 10 torr.
Claim 15
Dependent Claim
23 words
The method of claim 1 in which said plasma ashing occurs at radio frequency power levels from about 50 to about 300 watts.
Claim 16
Independent Claim
86 words
A method for deposition of gate electrode material in an inverted thin film field effect transistor, said method comprising the steps of: disposing a layer of titanium on an insulative substrate layer; coating said titanium mayer with a positive photoresist; exposing said photoresist through a desired pattern mask to create a pattern of exposed resistor material; developing said resist layer; plasma etching said titanium beneath said exposed resist; plasma ashing at least some of the remaining resist in an oxygen atmosphere; and stripping any remaining resist.
Claim 17
Independent Claim
86 words
A method for deposition of gate electrode material in an inverted thin film field effect transistor, said method comprising the steps of: disposing a layer of titanium on an insulative substrate layer; coating said titanium mayer with a positive photoresist; exposing said photoresist through a desired pattern mask to create a pattern of exposed resistor material; developing said resist layer; plasma etching said titanium beneath said exposed resist; plasma ashing at least some of the remaining resist in an oxygen atmosphere; and stripping any remaining resist.
Claim 18
Dependent Claim
21 words
The method of claim 15 in which said plasma ashing occurs at temperatures from about 80° C. to about 150° C.
Claim 19
Dependent Claim
20 words
The method of claim 15 in which said plasma ashing occurs at pressures from about 0.1 to about 10 torr.
Claim 20
Dependent Claim
23 words
The method of claim 15 in which said plasma ashing occurs at radio frequency power levels from about 50 to about 300 watts.
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) | 1990-03-02 | 1990-09-01 | 1991-03-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-03-02 | 1994-09-01 | 1995-03-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-03-02 | 1998-09-01 | 1999-03-03 | $7700.00 | Window Closed / Lapsed |