Patent US2471579A successfully refreshed from Google Patents.
US5656128A
Expired / Lapsed
US
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Reduction of reflection by amorphous carbon
Assignee: Fujitsu Ltd
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Filing: 1994-03-24
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Granted: 1997-08-12
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Expires: 2014-03-24
Abstract
Abstract A pattern forming method having a step of forming an amorphous carbon film on a patterning layer formed on a substrate, a step of forming a photoresist film on the amorphous carbon film, a step of selectively exposing and developing the photoresist film to form a photoresist pattern, and a step of successively dry-etching the amorphous carbon film and the patterning layer by using the photoresist film as an etching mask. Desired optical constants of an amorphous carbon film formed by sputtering can be obtained by controlling a substrate temperature and other parameters.
Inventors
- 👤 Koichi Hashimoto
- 👤 Toshiyuki Ohtsuka
- 👤 Fumihiko Shinpuku
- 👤 Daisuke Matsunaga
- 👤 Takayuki Enda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 13:39
CPC Classifications
G; G03; G03F; G03F7/00; H; H10; H10P; H10P50/00; H10P50/71; H10P50/20; H10P50/26; H10P50/264; H10P50/266; H10P50/267; H10P50/268; H10P50/28; H10P50/286; H10P50/287; H10P76/00; H10P76/20; H10P76/204; H10P76/2041; H10P76/2043; Y; Y10; Y10S; Y10S438/00; Y10S438/942; Y10S438/948; Y10S438/95; Y10S438/952
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
73 words
A pattern forming method comprising the steps of: forming an amorphous carbon film on a patterning layer formed on a substrate; forming a photoresist film on said amorphous carbon film; selectively exposing and developing said photoresist film to form a photoresist pattern; successively dry-etching said amorphous carbon film and said patterning layer in one etching step using said photoresist film as an etching mask; and removing said photoresist pattern and said amorphous carbon.
Claim 2
Dependent Claim
73 words
A pattern forming method comprising the steps of: forming an amorphous carbon film on a patterning layer formed on a substrate; forming a photoresist film on said amorphous carbon film; selectively exposing and developing said photoresist film to form a photoresist pattern; successively dry-etching said amorphous carbon film and said patterning layer in one etching step using said photoresist film as an etching mask; and removing said photoresist pattern and said amorphous carbon.
Claim 3
Dependent Claim
43 words
A method according to claim 1, wherein said successive dry-etching step includes an etching step using an etching gas in the form of plasma containing at least one of fluorine and chlorine for etching both said amorphous carbon film and said patterning layer.
Claim 4
Dependent Claim
19 words
A method according to claim 2, wherein said etching gas consists essentially of Cl 2 and O 2 .
Claim 5
Dependent Claim
21 words
A method according to claim 2, wherein said etching gas consists essentially of CF 4 , CHF 3 , and Ar.
Claim 6
Dependent Claim
17 words
A method according to claim 2, wherein said etching gas consists essentially of CF 4 and Ar.
Claim 7
Dependent Claim
23 words
A method according to claim 2, wherein said etching gas consists essentially of Cl 2 , BCl 3 , and N 2 .
Claim 8
Dependent Claim
38 words
A method according to claim 2, wherein said patterning layer is a layer formed on an underlying layer made of a material different from said patterning layer, and said dry etching step does not etch said underlying layer.
Claim 9
Dependent Claim
26 words
A method according to claim 7, wherein said patterning layer is polycrystalline silicon, refractory metal silicide, or polycide, and said underlying layer is an insulating material.
Claim 10
Dependent Claim
22 words
A method according to claim 7, wherein said patterning layer is an insulating material, and said underlying layer is a conductive material.
Claim 11
Dependent Claim
28 words
A method according to claim 2, wherein said step of removing said photoresist pattern and said amorphous carbon film comprises ashing with oxygen plasma after said dry-etching step.
Claim 12
Dependent Claim
17 words
A method according to claim 1, wherein said amorphous carbon film forming step is a sputtering process.
Claim 13
Dependent Claim
16 words
A method according to claim 11, wherein said sputtering process is a DC magnetron sputtering process.
Claim 14
Dependent Claim
62 words
A method according to claim 11, wherein said sputtering process is performed by setting a substrate temperature so as to make the real part of a complex refractive index of said amorphous carbon film fall in a range from 1.5 to 2.1 and make the imaginary part fall in a range from 0.6 to 1.0, respectively at a wavelength of 365 nm.
Claim 15
Dependent Claim
24 words
A method according to claim 13, wherein said amorphous carbon film is formed to a thickness in a range from 10 to 100 nm.
Claim 16
Dependent Claim
70 words
A method according to claim 11, wherein said sputtering process is performed by setting a substrate temperature, an atmospheric gas pressure, and a sputtering power so as to make the real part of a complex refractive index of said amorphous carbon film fall in a range from 1.5 to 2.1 and make the imaginary part fall in a range from 0.8 to 1.0, respectively at a wavelength of 365 nm.
Claim 17
Dependent Claim
62 words
A method according to claim 11, wherein said sputtering process is performed by setting a substrate temperature so as to make the real part of a complex refractive index of said amorphous carbon film fall in a range from 0.5 to 2.0 and make the imaginary part fall in a range from 0.3 to 1.8, respectively at a wavelength of 248 nm.
Claim 18
Dependent Claim
24 words
A method according to claim 16, wherein said amorphous carbon film is formed to a thickness in a range from 10 to 100 nm.
Claim 19
Dependent Claim
70 words
A method according to claim 11, wherein said sputtering process is performed by setting a substrate temperature, an atmospheric gas pressure, and a sputtering power so as to make the real part of a complex refractive index of said amorphous carbon film fall in a range from 0.5 to 2.0 and make the imaginary part fall in a range from 0.3 to 1.8, respectively at a wavelength of 248 nm.
Claim 20
Dependent Claim
21 words
A method according to claim 13, further comprising a step of pre-heating said substrate before said amorphous carbon film forming step.
Claim 21
Dependent Claim
21 words
A method according to claim 16, further comprising a step of pre-heating said substrate before said amorphous carbon film forming step.
Claim 22
Dependent Claim
31 words
An etching method wherein an amorphous carbon film exposed in an opening of a resist pattern is selectively etched by using an etching gas containing chlorine in the form of plasma.
Claim 23
Dependent Claim
31 words
An etching method wherein an amorphous carbon film exposed in an opening of a resist pattern is selectively etched by using an etching gas containing chlorine in the form of plasma.
Claim 24
Dependent Claim
17 words
A method according to claim 2, wherein said etching gas comprises CF 4 and CHF 3 .
Claim 25
Dependent Claim
14 words
A method according to claim 2, wherein said etching gas comprises CF 4 .
Claim 26
Dependent Claim
17 words
A method according to claim 2, wherein said etching gas comprises Cl 2 and BCl 3 .
Claim 27
Dependent Claim
28 words
A method according to claim 7, further comprising a step of etching said underlying layer, before said step of removing the photoresist pattern and the amorphous carbon film.
Claim 28
Dependent Claim
31 words
A method according to claim 9, further comprising a step of etching said underlying layer of conductive material, before said step of removing the photoresist pattern and the amorphous carbon film.
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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) | 2000-08-11 | 2001-02-10 | 2001-08-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-08-11 | 2005-02-10 | 2005-08-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-08-11 | 2009-02-10 | 2009-08-12 | $7700.00 | Window Closed / Lapsed |