US6451703B1
Expired / Lapsed
US
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Magnetically enhanced plasma etch process using a heavy fluorocarbon etching gas
Assignee: Applied Materials Inc
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Filing: 2000-03-10
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Granted: 2002-09-17
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Expires: 2020-03-10
Abstract
Abstract An oxide etch process practiced in magnetically enhanced reactive ion etch (MERIE) plasma reactor. The etching gas includes approximately equal amounts of a hydrogen-free fluorocarbon, most preferably C4F6, and oxygen and a much larger amount of argon diluent gas. The magnetic field is preferably maintained above about 50 gauss and the pressure at 40 milliTorr or above with chamber residence times of less than 70 milliseconds. A two-step process may be used for etching holes with very high aspect ratios. In the second step, the magnetic filed and the oxygen flow are reduced. Other fluorocarbons may be substituted which have F/C ratios of less than 2 and more preferably no more than 1.6 or 1.5.
Inventors
- 👤 Jingbao Liu
- 👤 Takehiko Komatsu
- 👤 Hongqing Shan
- 👤 Keji Horioka
- 👤 Bryan Y Pu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 10:28
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/20; H10P50/24; H10P50/242; H10P50/28; H10P50/282; H10P50/283; H10W; H10W20/00; H10W20/01; H10W20/071; H10W20/081
Claims Analysis
Total Claims: 54
Claim 1
Independent Claim
141 words
A method for etching an oxide layer with increased selectivity to photoresist, comprising the steps of: providing a magnetically enhanced plasma etch reactor chamber having a pedestal electrode supporting a substrate having said oxide layer to be etched; flowing into said chamber an etching gas mixture comprising (a) hexafluorobutadiene, (b) oxygen, and (c) a chemically inactive carrier gas selected from the group consisting of argon and xenon and containing essentially no carbon monoxide; applying a magnetic field substantially parallel to said pedestal electrode; and applying RF electrical power to said pedestal electrode to provide the only significant power to excite said etching gas mixture into a plasma to thereby etch a hole into said oxide layer defined by a patterned photomask comprising photoresist overlying said oxide layer with an etching selectivity to a facet of said photoresist of at least 5:1.
Claim 2
Independent Claim
141 words
A method for etching an oxide layer with increased selectivity to photoresist, comprising the steps of: providing a magnetically enhanced plasma etch reactor chamber having a pedestal electrode supporting a substrate having said oxide layer to be etched; flowing into said chamber an etching gas mixture comprising (a) hexafluorobutadiene, (b) oxygen, and (c) a chemically inactive carrier gas selected from the group consisting of argon and xenon and containing essentially no carbon monoxide; applying a magnetic field substantially parallel to said pedestal electrode; and applying RF electrical power to said pedestal electrode to provide the only significant power to excite said etching gas mixture into a plasma to thereby etch a hole into said oxide layer defined by a patterned photomask comprising photoresist overlying said oxide layer with an etching selectivity to a facet of said photoresist of at least 5:1.
Claim 3
Independent Claim
216 words
A method for etching an oxide layer with increased selectivity to photoresist, comprising the steps of: providing a magnetically enhanced plasma etch reactor chamber having a pedestal electrode supporting a substrate having said oxide layer to be etched in opposition to a showerhead and further including at least one magnetic coil positioned on a side of said showerhead towards said pedestal electrodes; flowing through said showerhead into said chamber an etching gas mixture comprising (a) a fluorocarbon having at least four carbon atoms and an F/C ratio of less than 2, (b) oxygen, and (c) a chemically inactive carrier gas selected from the group consisting of argon and xenon; applying a magnetic field substantially parallel to said pedestal electrode by powering said at least one magnetic coil; and applying RF electrical power to said pedestal electrode to excite said etching gas mixture into a plasma to thereby etch a hole into said oxide layer defined by a patterned photomask comprising photoresist overlying said oxide layer with an etching selectivity to a facet of said photoresist of at least 5:1; wherein in a first step said magnetic field is applied to a first field strength and wherein in a second step said magnetic field is applied to a second field strength less than said first field strength.
Claim 4
Independent Claim
216 words
A method for etching an oxide layer with increased selectivity to photoresist, comprising the steps of: providing a magnetically enhanced plasma etch reactor chamber having a pedestal electrode supporting a substrate having said oxide layer to be etched in opposition to a showerhead and further including at least one magnetic coil positioned on a side of said showerhead towards said pedestal electrodes; flowing through said showerhead into said chamber an etching gas mixture comprising (a) a fluorocarbon having at least four carbon atoms and an F/C ratio of less than 2, (b) oxygen, and (c) a chemically inactive carrier gas selected from the group consisting of argon and xenon; applying a magnetic field substantially parallel to said pedestal electrode by powering said at least one magnetic coil; and applying RF electrical power to said pedestal electrode to excite said etching gas mixture into a plasma to thereby etch a hole into said oxide layer defined by a patterned photomask comprising photoresist overlying said oxide layer with an etching selectivity to a facet of said photoresist of at least 5:1; wherein in a first step said magnetic field is applied to a first field strength and wherein in a second step said magnetic field is applied to a second field strength less than said first field strength.
Claim 5
Dependent Claim
26 words
The method of claim 1 , wherein a ratio of a flow of said oxygen to a flow of said hexafluorobutadiene is between 0.4:1 and 2:1.
Claim 6
Dependent Claim
18 words
The method of claim 2 , wherein said fluorocarbon has an F/C ratio of no more than 1.6.
Claim 7
Dependent Claim
14 words
The method of claim 4 , said fluorocarbon comprises C 4 F 6 .
Claim 8
Dependent Claim
27 words
The method of claim 1 , wherein a second ratio of a flow of said carrier gas to a flow of said hexafluorobutadiene is at least 10.
Claim 9
Independent Claim
168 words
A method for etching an oxide layer with increased selectivity to photoresist, comprising the steps of: providing a magnetically enhanced plasma etch reactor chamber having a pedestal electrode supporting a substrate having said oxide layer to be etched; flowing into said chamber an etching gas mixture comprising (a) a fluorocarbon having at least four carbon atoms and an F/C ratio of less than 2, (b) oxygen, and (c) a chemically inactive carrier gas selected from the group consisting of argon and xenon; applying a magnetic field substantially parallel to said pedestal electrode; and applying RF electrical power to said pedestal electrode to excite said etching gas mixture into a plasma to thereby etch a hole into said oxide layer defined by a patterned photomask comprising photoresist overlying said oxide layer with an etching selectivity to a facet of said photoresist of at least 5:1; and vacuum pumping said chamber to maintain a residence time of said etching gas mixture in said chamber of no more than 70 milliseconds.
Claim 10
Independent Claim
168 words
A method for etching an oxide layer with increased selectivity to photoresist, comprising the steps of: providing a magnetically enhanced plasma etch reactor chamber having a pedestal electrode supporting a substrate having said oxide layer to be etched; flowing into said chamber an etching gas mixture comprising (a) a fluorocarbon having at least four carbon atoms and an F/C ratio of less than 2, (b) oxygen, and (c) a chemically inactive carrier gas selected from the group consisting of argon and xenon; applying a magnetic field substantially parallel to said pedestal electrode; and applying RF electrical power to said pedestal electrode to excite said etching gas mixture into a plasma to thereby etch a hole into said oxide layer defined by a patterned photomask comprising photoresist overlying said oxide layer with an etching selectivity to a facet of said photoresist of at least 5:1; and vacuum pumping said chamber to maintain a residence time of said etching gas mixture in said chamber of no more than 70 milliseconds.
Claim 11
Dependent Claim
16 words
The method of claim 7 , wherein said etching gas mixture contains essentially no carbon monoxide.
Claim 12
Dependent Claim
15 words
The method of claim 7 , wherein said etching gas mixture additionally comprises carbon monoxide.
Claim 13
Independent Claim
95 words
A method of etching a hole in an oxide layer, comprising the steps of: providing a magnetically enhanced reactive ion plasma etch reactor; flowing into said reactor an etching gas mixture comprising a first amount of C 4 F 6 , a second amount of O 2 , and a third amount of argon and containing essentially no carbon monoxide; applying a magnetic field in said reactor; applying RF power to a pedestal electrode supporting a substrate containing said oxide layer to excite said etching gas mixture into a plasma to etch said oxide layer.
Claim 14
Independent Claim
95 words
A method of etching a hole in an oxide layer, comprising the steps of: providing a magnetically enhanced reactive ion plasma etch reactor; flowing into said reactor an etching gas mixture comprising a first amount of C 4 F 6 , a second amount of O 2 , and a third amount of argon and containing essentially no carbon monoxide; applying a magnetic field in said reactor; applying RF power to a pedestal electrode supporting a substrate containing said oxide layer to excite said etching gas mixture into a plasma to etch said oxide layer.
Claim 15
Dependent Claim
22 words
The method of claim 10 , wherein a ratio of said second amount to said first amount is between 0.5:1 and 1.2:1.
Claim 16
Dependent Claim
21 words
The method of claim 11 , wherein a ratio of said third amount to said first amount is greater than 20.
Claim 17
Dependent Claim
20 words
The method of claim 10 , further comprising vacuum pumping said reactor to a pressure of at least 40 milliTorr.
Claim 18
Dependent Claim
29 words
The method of claim 12 , wherein said vacuum pumping step maintains a residence time of said etching gas mixture in said reactor of no more than 70 milliseconds.
Claim 19
Dependent Claim
20 words
The method of claim 10 , wherein said magnetic field is applied to a level of at least 35 gauss.
Claim 20
Dependent Claim
25 words
The method of claim 10 , wherein said RF power is applied in an amount between 1650 and 2100W normalized to a 200 mm-diameter wafer.
Claim 21
Dependent Claim
42 words
The method of claim 10 , wherein said applying step applies said magnetic field in a first step to a level of at least 50 gauss and applies said magnetic field in a second step to a level less than 50 gauss.
Claim 22
Dependent Claim
36 words
The method of claim 10 , wherein said oxide layer is patterned with a layer of photoresist and wherein said plasma etches said oxide layer selectively to a facet of said photoresist of at least 5:1.
Claim 23
Dependent Claim
40 words
The method of claim 10 , wherein a first ratio of said second amount to said first amount is between 0.4:1 to 2:1 and wherein a second ratio of said third amount to said first amount is at least 10.
Claim 24
Dependent Claim
19 words
The method of claim 1 , wherein said magnetic field has a field strength of greater than 35 Gauss.
Claim 25
Dependent Claim
18 words
The method of claim 2 , wherein said plasma etch reactor is capacitively coupled to form said plasma.
Claim 26
Dependent Claim
11 words
The method of claim 2 , wherein said fluorocarbon is hydrogen-free.
Claim 27
Dependent Claim
16 words
An The method of claim 22 , wherein said fluorocarbon comprises C 4 F 6 .
Claim 28
Dependent Claim
17 words
The method of claim 2 , wherein said first field strength level is greater than 50 Gauss.
Claim 29
Dependent Claim
17 words
The method of claim 24 , wherein said second field strength level is greater than 35 Gauss.
Claim 30
Dependent Claim
11 words
The method of claim 7 , wherein said fluorocarbon is hydrogen-free.
Claim 31
Dependent Claim
15 words
The method of claim 26 , wherein said fluorocarbon comprises C 4 F 6 .
Claim 32
Dependent Claim
19 words
The method of claim 7 , wherein said magnetic field has a field strength of greater than 35 Gauss.
Claim 33
Dependent Claim
164 words
In a magnetically enhanced plasma etch reactor chamber having a pedestal electrode in opposition to a showerhead, a method for etching an oxide layer in a substrate supported on said pedestal electrode in said chamber, comprising two sequentially performed steps each comprising the sub-steps of: flowing into said chamber through said showerhead an etching gas mixture comprising (a) a fluorocarbon and (b) a chemically inactive carrier gas selected from the group consisting of argon and xenon; applying a magnetic field adjacent to said pedestal electrode; and applying RF electrical power to said pedestal electrode to excite said etching gas mixture into a plasma to thereby etch a hole into said oxide layer defined by a patterned photomask comprising photoresist overlying said oxide layer; wherein during a first one of said steps said magnetic field has a first field strength level and during a second one of said steps said magnetic field has a second field strength level less than said first field strength level.
Claim 34
Dependent Claim
164 words
In a magnetically enhanced plasma etch reactor chamber having a pedestal electrode in opposition to a showerhead, a method for etching an oxide layer in a substrate supported on said pedestal electrode in said chamber, comprising two sequentially performed steps each comprising the sub-steps of: flowing into said chamber through said showerhead an etching gas mixture comprising (a) a fluorocarbon and (b) a chemically inactive carrier gas selected from the group consisting of argon and xenon; applying a magnetic field adjacent to said pedestal electrode; and applying RF electrical power to said pedestal electrode to excite said etching gas mixture into a plasma to thereby etch a hole into said oxide layer defined by a patterned photomask comprising photoresist overlying said oxide layer; wherein during a first one of said steps said magnetic field has a first field strength level and during a second one of said steps said magnetic field has a second field strength level less than said first field strength level.
Claim 35
Dependent Claim
17 words
The method of claim 29 , wherein said magnetic field is substantially parallel to said pedestal electrode.
Claim 36
Dependent Claim
35 words
The method of claim 29 , wherein said step of applying a magnetic field comprises applying a current to at least one magnetic coil disposed on a side of said showerhead toward said pedestal electrode.
Claim 37
Dependent Claim
32 words
The method of claim 31 , wherein a plurality of said magnetic coils surround said chamber and cause said magnetic field to rotate and to be substantially parallel to said pedestal electrode.
Claim 38
Dependent Claim
14 words
The method of claim 29 , wherein said etching gas mixture additionally comprises oxygen.
Claim 39
Dependent Claim
23 words
The method of claim 29 , wherein said fluorocarbon has at least four carbon atoms and an F/C ratio of less than 2.
Claim 40
Dependent Claim
11 words
The method of claim 34 , wherein said fluorocarbon comprises hexafluorobutadiene.
Claim 41
Dependent Claim
14 words
The method of claim 34 , wherein said etching gas mixture additionally comprises oxygen.
Claim 42
Dependent Claim
164 words
In a magnetically enhanced plasma etch reactor chamber having a pedestal electrode, a method for etching an oxide layer in a substrate supported on said pedestal electrode in said chamber, comprising two sequentially performed steps each comprising the sub-steps of: flowing into said chamber an etching gas mixture comprising (a) a fluorocarbon having at least four carbon atoms and an F/C ratio of less than 2, (b) oxygen, and (c) a chemically inactive carrier gas selected from the group consisting of argon and xenon; applying a magnetic field substantially parallel to said pedestal electrode; and applying RF electrical power to said pedestal electrode to excite said etching gas mixture into a plasma to thereby etch a hole into said oxide layer defined by a patterned photomask comprising photoresist overlying said oxide layer; wherein a ratio of a flow of said oxygen to a flow of said fluorocarbon is higher in a first one of said steps than in a second one of said steps.
Claim 43
Dependent Claim
164 words
In a magnetically enhanced plasma etch reactor chamber having a pedestal electrode, a method for etching an oxide layer in a substrate supported on said pedestal electrode in said chamber, comprising two sequentially performed steps each comprising the sub-steps of: flowing into said chamber an etching gas mixture comprising (a) a fluorocarbon having at least four carbon atoms and an F/C ratio of less than 2, (b) oxygen, and (c) a chemically inactive carrier gas selected from the group consisting of argon and xenon; applying a magnetic field substantially parallel to said pedestal electrode; and applying RF electrical power to said pedestal electrode to excite said etching gas mixture into a plasma to thereby etch a hole into said oxide layer defined by a patterned photomask comprising photoresist overlying said oxide layer; wherein a ratio of a flow of said oxygen to a flow of said fluorocarbon is higher in a first one of said steps than in a second one of said steps.
Claim 44
Dependent Claim
11 words
The method of claim 37 , wherein said fluorocarbon is hydrogen-free.
Claim 45
Dependent Claim
15 words
The method of claim 38 , wherein said fluorocarbon comprises C 4 F 6 .
Claim 46
Dependent Claim
15 words
The method of claim 37 , wherein said fluorocarbon comprises C 5 F 8 .
Claim 47
Dependent Claim
15 words
The method of claim 26 , wherein said fluorocarbon comprises C 5 F 8 .
Claim 48
Dependent Claim
15 words
The method of claim 34 , wherein said fluorocarbon comprises C 5 F 8 .
Claim 49
Independent Claim
144 words
A method for etching an oxide layer, comprising the steps of: providing a magnetically enhanced plasma etch reactor chamber having a pedestal electrode supporting in opposition to a showerhead a substrate having said oxide layer to be etched; flowing through said showerhead into said chamber an etching gas comprising (a) a fluorocarbon selected from the group consisting of C 4 F 6 , C 5 F 8 , and C 6 F 6 , (b) oxygen, and (c) a chemically inactive carrier gas selected from the group consisting of argon and xenon, said etching gas including essentially no CO; applying a magnetic field parallel to said pedestal electrode; and applying RF electrical power to said pedestal electrode to excite said etching gas mixture into a plasma to thereby etch a hole into said oxide layer defined by a patterned photomask overlying said oxide layer.
Claim 50
Independent Claim
144 words
A method for etching an oxide layer, comprising the steps of: providing a magnetically enhanced plasma etch reactor chamber having a pedestal electrode supporting in opposition to a showerhead a substrate having said oxide layer to be etched; flowing through said showerhead into said chamber an etching gas comprising (a) a fluorocarbon selected from the group consisting of C 4 F 6 , C 5 F 8 , and C 6 F 6 , (b) oxygen, and (c) a chemically inactive carrier gas selected from the group consisting of argon and xenon, said etching gas including essentially no CO; applying a magnetic field parallel to said pedestal electrode; and applying RF electrical power to said pedestal electrode to excite said etching gas mixture into a plasma to thereby etch a hole into said oxide layer defined by a patterned photomask overlying said oxide layer.
Claim 51
Dependent Claim
35 words
The method of claim 43 , wherein said photomask comprises photoresist and wherein said plasma of said etching gas mixture etches said oxide layer with an etching selectivity to said photoresist of at least 5:1.
Claim 52
Dependent Claim
15 words
The method of claim 43 , wherein said fluorocarbon comprises C 4 F 6 .
Claim 53
Dependent Claim
15 words
The method of claim 43 , wherein said fluorocarbon comprises C 5 F 8 .
Claim 54
Dependent Claim
39 words
The method of claim 43 : wherein at least one magnetic coil is disposed on a side of said showerhead towards said pedestal electrode; and a wherein said step of applying said magnetic field comprises powering said magnetic coil.
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