US5858879A
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Method for etching metal lines with enhanced profile control
Assignee: Taiwan Semiconductor Manufacturing Co TSMC Ltd
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Filing: 1997-06-06
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Granted: 1999-01-12
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Expires: 2017-06-06
Abstract
Abstract The present invention discloses a method for enhancing profile control in a metal line etching process in which a main etching step and an over etching step are used by incorporating a charge neutralization step for the photoresist layer by an inert gas plasma such that plasma ions aimed at the horizontal surface on the semiconductor substrate is not distorted to bombard the sidewalls on the metal lines. The anisotropic etching of the metal lines is improved to provide metal lines on a device that has enhanced profile control and without the void or cavity defect.
Inventors
- 👤 L. C. Chao
- 👤 M. H. Huang
- 👤 C. H. Yu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 13:08
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/20; H10P50/26; H10P50/264; H10P50/266; H10P50/267; H10P50/71
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
80 words
A method for etching metal lines with enhanced profile control comprising the steps of: providing a semiconductor device having a metal layer deposited on top, depositing and patterning a photoresist layer on top of said metal layer, plasma etching lines in said metal layer and stopping at a metal/TiN interface in a first etching step, neutralizing charges in said photoresist layer by an inert gas plasma, and plasma etching said lines through said TiN layer in a second etching step.
Claim 2
Independent Claim
80 words
A method for etching metal lines with enhanced profile control comprising the steps of: providing a semiconductor device having a metal layer deposited on top, depositing and patterning a photoresist layer on top of said metal layer, plasma etching lines in said metal layer and stopping at a metal/TiN interface in a first etching step, neutralizing charges in said photoresist layer by an inert gas plasma, and plasma etching said lines through said TiN layer in a second etching step.
Claim 3
Dependent Claim
25 words
A method according to claim 1, wherein said metal layer comprises a metal stack of TiN/Metal/TiN/Ti with the Ti layer next to the semiconductor device.
Claim 4
Dependent Claim
25 words
A method according to claim 1, wherein said metal layer is deposited of a material selected from the group consisting of Al, AlCu and AlCuSi.
Claim 5
Dependent Claim
20 words
A method according to claim 1, wherein said photoresist layer generates a passivation material when bombarded by a gas plasma.
Claim 6
Dependent Claim
40 words
A method according to claim 1, wherein said photoresist layer generates a passivation material for coating the sidewalls of the metal line when bombarded by a gas plasma of N 2 , BCl 3 or N 2 /BCl 3 .
Claim 7
Dependent Claim
17 words
A method according to claim 1, wherein said first etching step is stopped by an end-point mode.
Claim 8
Dependent Claim
17 words
A method according to claim 1, wherein said second etching step is stopped by a time mode.
Claim 9
Dependent Claim
25 words
A method according to claim 1, wherein said first etching step is a main etching step and said second etching step is an over-etching step.
Claim 10
Dependent Claim
25 words
A method according to claim 6, wherein said first etching step is stopped when a drop in Al emission is detected in an end mode.
Claim 11
Dependent Claim
22 words
A method according to claim 7, wherein said second etching step is stopped after between about 30 seconds and about 120 seconds.
Claim 12
Dependent Claim
19 words
A method according to claim 1, wherein said inert gas plasma is an argon plasma or a helium plasma.
Claim 13
Dependent Claim
29 words
A method according to claim 1, wherein said neutralization step for said charges in the photoresist layer substantially eliminates distortion in ion paths during said second plasma etching step.
Claim 14
Independent Claim
95 words
A method for enhancing profile control in a metal line etching process comprising the steps of: providing a semiconductor device having a metal layer deposited on top, depositing and patterning a photoresist layer on top of said metal layer, said photoresist layer produces a passivation material in a gas plasma, anisotropically etching lines in said metal layer in a first etching step stopped by an end-point mode, neutralizing electrostatic charges built-up in said photoresist layer by an inert gas plasma, and anisotropically etching said lines in a second etching step stopped by a time mode.
Claim 15
Independent Claim
95 words
A method for enhancing profile control in a metal line etching process comprising the steps of: providing a semiconductor device having a metal layer deposited on top, depositing and patterning a photoresist layer on top of said metal layer, said photoresist layer produces a passivation material in a gas plasma, anisotropically etching lines in said metal layer in a first etching step stopped by an end-point mode, neutralizing electrostatic charges built-up in said photoresist layer by an inert gas plasma, and anisotropically etching said lines in a second etching step stopped by a time mode.
Claim 16
Dependent Claim
24 words
A method according to claim 13, wherein said metal layer comprises a metal stack of TiN/Metal/Tin/Ti with the Ti layer contacting said semiconductor substrate.
Claim 17
Dependent Claim
25 words
A method according to claim 13, wherein said metal layer is deposited of a material selected from the group consisting of Al, AlCu and AllCuSi.
Claim 18
Dependent Claim
17 words
A method according to claim 13, wherein said inert gas plasma is generated by argon or helium.
Claim 19
Dependent Claim
28 words
A method according to claim 13, wherein the plasma that produces the passivation material is generated by N 2 , BCl 3 or N 2 /BCl 3 .
Claim 20
Dependent Claim
22 words
A method according to claim 13, wherein said first and said second etching steps are conducted in a reactive ion etching chamber.
Claim 21
Dependent Claim
32 words
A method according to claim 13, wherein said first and said second etching steps are carried out by an etchant gas mixture of Cl 2 , BCl 3 and N 2 .
Claim 22
Dependent Claim
29 words
A method according to claim 14, wherein said first and said second etching steps are carried out for a time period sufficient to remove substantially all the metal stack.
References Cited (Backward Citations)
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