EP0849789A2
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EP
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Method of etching a multilayer IC dielectric structure
Assignee: Texas Instruments Inc
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Filing: 1997-12-22
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Granted: —
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Expires: 2017-12-22
Abstract
Abstract A method of etching an integrated circuit structure in which the gas flows into the etch plasma are changed to compensate for the change in the etch chemistry which occurs when deep features (high aspect ratio) or multilayer structures are etched. This innovative process divides the etch into multiple steps and changes the etch parameters during each stage of the etch in response to the materials being etched during that stage of the etch. <IMAGE>
Inventors
- 👤 David B. Aldrich
- 👤 Peter S. Mcanally
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 21:36
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/20; H10P50/28; H10P50/282; H10P50/283; H10P50/73; H10W; H10W20/00; H10W20/01; H10W20/071; H10W20/081
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
100 words
A method of etching a multilayer integrated circuit
dielectric structure which includes, in at least some locations,
an upper portion overlying a lower portion, and wherein said
upper portion contains a higher net excess of polymer-etchant
atoms over polymer-precursor atoms than does said lower portion,
comprising the steps of: etching said upper portion using plasma-excitation of a
first fluorine-containing chemistry; and etching said lower portion using plasma-excitation of a
second fluorine-containing chemistry which contains a larger net
excess of polymer etchant atoms over polymer-precursor atoms
than said first chemistry; whereby the formation of polymers on said lower portion is
prevented.
Claim 2
Dependent Claim
14 words
The method of Claim 1, wherein said second chemistry
predominantly comprises C2F6 and oxygen.
Claim 3
Dependent Claim
15 words
The method of Claim 1 or Claim 2, wherein said first
chemistry predominantly comprises C2F6.
Claim 4
Independent Claim
22 words
The method of any of Claims 1 to 3, wherein said first
chemistry and said second chemistry are alternated more than
once.
Claim 5
Independent Claim
21 words
The method of any of Claims 1 to 4, wherein said lower
portion substantially comprises SiOx with x less than 1.9.
Claim 6
Independent Claim
23 words
The method of any of Claims 1 to 5, wherein said second
chemistry contains a higher fraction of oxygen than said first
chemistry.
Claim 7
Independent Claim
23 words
The method of any of Claims 1 to 6, wherein said second
chemistry contains a lower fraction of carbon than said first
chemistry.
Claim 8
Independent Claim
24 words
The method of any of Claims 1 to 7, further comprising the
subsequent step of: further etching using plasma-excitation of said first
fluorine-containing chemistry.
Claim 9
Independent Claim
21 words
The method of any of Claims 1 to 8, wherein said lower
portion comprises at least ten percent atomic of carbon.
Claim 10
Independent Claim
19 words
The method of any of any of Claims 1 to 9, wherein said
lower portion is an organic polymer.
Claim 11
Independent Claim
14 words
The method of Claims 1 to 10, wherein said upper portion
predominantly comprises SiO2.
Claim 12
Independent Claim
95 words
A method of etching a multilayer integrated circuit
dielectric structure which includes, in at least some locations,
an upper oxide portion overlying a lower portion, both said
portions comprising silicon and oxygen, said lower portion
containing a smaller atomic fraction of oxygen than said upper
portion, comprising the steps of: etching said upper portion using plasma-excitation of a
first fluorine-containing chemistry; and etching said lower portion using plasma-excitation of a
second fluorine-containing chemistry which contains a higher
fraction of oxygen than said first chemistry; whereby the formation of polymers on said lower portion is
prevented.
Claim 13
Dependent Claim
14 words
The method of Claim 12, wherein said second chemistry
predominantly comprises C2F6 and oxygen.
Claim 14
Dependent Claim
15 words
The method of Claim 12 or Claim 13, wherein said first
chemistry predominantly comprises C2F6.
Claim 15
Independent Claim
22 words
The method of any of Claims 12 to 14, wherein said first
chemistry and said second chemistry are alternated more than
once.
Claim 16
Independent Claim
128 words
A method of etching a multilayer integrated circuit
dielectric structure which includes an upper portion overlying a
lower portion and wherein said upper portion contains a higher
net excess of polymer-etchant atoms over polymer-precursor atoms
than does said lower portion, comprising the steps of: first etching through said upper portion using plasma-excitation
of a first fluorine-containing chemistry which does
not form polymers on horizontal portions of said upper layer,
but forms polymers on horizontal portions of said lower layer
and substantially stops etching; and second etching through said lower portion using plasma-excitation
of a second fluorine-containing chemistry which
contains a higher net excess of polymer etchant atoms over
polymer-precursor atoms than does said first chemistry; whereby said lower portion provides an etch stop for said
first etching step.
Claim 17
Dependent Claim
12 words
The method of Claim 16, wherein said first chemistry
predominantly comprises C2F6.
Claim 18
Dependent Claim
20 words
The method of Claim 16 or Claim 17, wherein said lower
portion substantially comprises SiOx with x less than 1.9.
Claim 19
Independent Claim
23 words
The method of any of Claims 16 to 18, wherein said lower
portion substantially comprises a high-organic-contact Siox
with x less than 1.9.
References Cited (Backward Citations)
No citation records indexed.
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