CN118160076A - Etching gas and etching method using the same - Google Patents
Etching gas and etching method using the same Download PDFInfo
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- CN118160076A CN118160076A CN202280071727.1A CN202280071727A CN118160076A CN 118160076 A CN118160076 A CN 118160076A CN 202280071727 A CN202280071727 A CN 202280071727A CN 118160076 A CN118160076 A CN 118160076A
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- 238000005530 etching Methods 0.000 title claims abstract description 167
- 238000000034 method Methods 0.000 title claims description 11
- 229910004298 SiO 2 Inorganic materials 0.000 claims abstract description 57
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 33
- 229910052814 silicon oxide Inorganic materials 0.000 claims abstract description 33
- 229910003481 amorphous carbon Inorganic materials 0.000 claims abstract description 31
- 239000007789 gas Substances 0.000 claims description 105
- 150000002927 oxygen compounds Chemical class 0.000 claims description 19
- 239000011261 inert gas Substances 0.000 claims description 16
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 9
- 239000002210 silicon-based material Substances 0.000 claims description 5
- 229910052799 carbon Inorganic materials 0.000 abstract description 4
- -1 1,2,3, 4-tetrafluoro-5- (fluoromethylene) cyclopent-1, 3-diene Chemical compound 0.000 description 17
- ZSWFCLXCOIISFI-UHFFFAOYSA-N cyclopentadiene Chemical compound C1C=CC=C1 ZSWFCLXCOIISFI-UHFFFAOYSA-N 0.000 description 11
- 230000001965 increasing effect Effects 0.000 description 9
- WACNXHCZHTVBJM-UHFFFAOYSA-N 1,2,3,4,5-pentafluorobenzene Chemical compound FC1=CC(F)=C(F)C(F)=C1F WACNXHCZHTVBJM-UHFFFAOYSA-N 0.000 description 8
- USPWUOFNOTUBAD-UHFFFAOYSA-N 1,2,3,4,5-pentafluoro-6-(trifluoromethyl)benzene Chemical compound FC1=C(F)C(F)=C(C(F)(F)F)C(F)=C1F USPWUOFNOTUBAD-UHFFFAOYSA-N 0.000 description 7
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- HWEQKSVYKBUIIK-UHFFFAOYSA-N cyclobuta-1,3-diene Chemical compound C1=CC=C1 HWEQKSVYKBUIIK-UHFFFAOYSA-N 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- TXEYQDLBPFQVAA-UHFFFAOYSA-N tetrafluoromethane Chemical compound FC(F)(F)F TXEYQDLBPFQVAA-UHFFFAOYSA-N 0.000 description 4
- 238000001312 dry etching Methods 0.000 description 3
- 238000009616 inductively coupled plasma Methods 0.000 description 3
- 125000002023 trifluoromethyl group Chemical group FC(F)(F)* 0.000 description 3
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 2
- 239000003054 catalyst Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- 235000012431 wafers Nutrition 0.000 description 2
- 238000010792 warming Methods 0.000 description 2
- LRUSRUZKYAWVRB-UHFFFAOYSA-N 1,2,3,4,5,6,7,7-octafluorocyclohepta-1,3,5-triene Chemical compound FC1=C(F)C(F)=C(F)C(F)(F)C(F)=C1F LRUSRUZKYAWVRB-UHFFFAOYSA-N 0.000 description 1
- TXCAZKMXLKWUTK-UHFFFAOYSA-N 1,2,3,5-tetrafluoro-4-(trifluoromethyl)benzene Chemical compound FC1=CC(F)=C(C(F)(F)F)C(F)=C1F TXCAZKMXLKWUTK-UHFFFAOYSA-N 0.000 description 1
- KJOHHPPNYVMWRE-UHFFFAOYSA-N 1,2,3-trifluoro-4-(trifluoromethyl)benzene Chemical compound FC1=CC=C(C(F)(F)F)C(F)=C1F KJOHHPPNYVMWRE-UHFFFAOYSA-N 0.000 description 1
- ZVPAJILXQHMKMT-UHFFFAOYSA-N 1,2,4,5-tetrafluoro-3-(trifluoromethyl)benzene Chemical compound FC1=CC(F)=C(F)C(C(F)(F)F)=C1F ZVPAJILXQHMKMT-UHFFFAOYSA-N 0.000 description 1
- AJNDNWYVKZRHBE-UHFFFAOYSA-N 1-(difluoromethyl)-2,3,4,5,6-pentafluorobenzene Chemical compound FC(F)C1=C(F)C(F)=C(F)C(F)=C1F AJNDNWYVKZRHBE-UHFFFAOYSA-N 0.000 description 1
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 1
- XPDWGBQVDMORPB-UHFFFAOYSA-N Fluoroform Chemical compound FC(F)F XPDWGBQVDMORPB-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- RWRIWBAIICGTTQ-UHFFFAOYSA-N difluoromethane Chemical compound FCF RWRIWBAIICGTTQ-UHFFFAOYSA-N 0.000 description 1
- 125000001028 difluoromethyl group Chemical group [H]C(F)(F)* 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 238000010494 dissociation reaction Methods 0.000 description 1
- 230000005593 dissociations Effects 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- XMBWDFGMSWQBCA-UHFFFAOYSA-N hydrogen iodide Chemical compound I XMBWDFGMSWQBCA-UHFFFAOYSA-N 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 229910052743 krypton Inorganic materials 0.000 description 1
- DNNSSWSSYDEUBZ-UHFFFAOYSA-N krypton atom Chemical compound [Kr] DNNSSWSSYDEUBZ-UHFFFAOYSA-N 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052754 neon Inorganic materials 0.000 description 1
- GKAOGPIIYCISHV-UHFFFAOYSA-N neon atom Chemical compound [Ne] GKAOGPIIYCISHV-UHFFFAOYSA-N 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- UXPOJVLZTPGWFX-UHFFFAOYSA-N pentafluoroethyl iodide Chemical compound FC(F)(F)C(F)(F)I UXPOJVLZTPGWFX-UHFFFAOYSA-N 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 229910052724 xenon Inorganic materials 0.000 description 1
- FHNFHKCVQCLJFQ-UHFFFAOYSA-N xenon atom Chemical compound [Xe] FHNFHKCVQCLJFQ-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
- H01L21/306—Chemical or electrical treatment, e.g. electrolytic etching
- H01L21/3065—Plasma etching; Reactive-ion etching
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Plasma & Fusion (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Manufacturing & Machinery (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Drying Of Semiconductors (AREA)
Abstract
An etching gas comprising C 7F8, further comprising C 7F7 H and/or C 6F5 H. An etching gas containing C 7F8 to 99.9% by volume, wherein the total amount of the etching gas is 100% by volume. A novel etching gas having a large ratio (SiO 2/ACL) of the etching rate of an Amorphous Carbon Layer (ACL) to the etching rate of a silicon oxide film (SiO 2).
Description
Technical Field
The present invention relates to an etching gas and an etching method using the same.
Background
As an etching gas using octafluorotoluene having a Global Warming Potential (GWP) as low as 4665, non-patent document 1 discloses an etching gas containing a composition of octafluorotoluene, ar, and O 2.
Prior art literature
Non-patent literature
Non-patent document 1: MATERIALS EXPRESS, vol.10, no.6,2020,903-908.
Disclosure of Invention
Technical problem to be solved by the invention
The purpose of the present invention is to provide a novel etching gas having a large ratio (SiO 2/ACL) between the etching rate of an Amorphous Carbon Layer (ACL) and the etching rate of a silicon oxide film (SiO 2).
Technical means for solving the technical problems
The present invention includes the following means.
Item 1. An etching gas comprising C 7F8, further comprising C 7F7 H and/or C 6F5 H.
The etching gas according to item 2, wherein the total amount of the etching gas is 100% by volume and C 7F8 to 99.9% by volume is contained.
Item 3. The etching gas according to item 1 or 2, further comprising an oxygen compound.
The etching gas according to item 3, wherein the oxygen compound contains water.
The etching gas according to item 4, wherein the total amount of the etching gas is 100 vol%, and the water content is 0.01 to 200 vol ppm.
The etching gas according to any one of items 1 to 5, further comprising an inert gas.
An etching method of etching a silicon-based material including a silicon oxide film (SiO 2 film) having an Amorphous Carbon Layer (ACL) formed on all or a part of the surface thereof by using the gas plasma of the etching gas described in any one of items 1 to 6.
Effects of the invention
According to the present invention, there is provided a novel etching gas having a large ratio (SiO 2/ACL) of the etching rate of an Amorphous Carbon Layer (ACL) to the etching rate of a silicon oxide film (SiO 2).
Detailed Description
In the present specification, the term "containing" includes any of "comprising", "consisting essentially of … … (consist essentially of) and" consisting of … … (consist of) only ".
In the present specification, when the numerical ranges "a to B" are represented, a is not less than a and not more than B.
In the process of manufacturing a 3d nand flash memory and the process of forming a contact hole of an insulating film such as SiO 2, it is necessary to etch a silicon oxide film (SiO 2) selectively to an Amorphous Carbon Layer (ACL) as a mask. Although Perfluorocarbon (PFC) is used for the etching, a technique has been conventionally demanded that SiO 2 has a sufficient etching selectivity to ACL and that can suppress defects.
Non-patent document 1 shows that when octafluorotoluene is 30sccm, ar is 30sccm, and O 2 is 30 to 60sccm, the SiO 2/ACL etching selectivity (etching rate ratio) is higher than when the flow rate of O 2 is smaller. However, non-patent document 1 does not disclose the use of octafluorotoluene in combination with other etching gases, nor does it disclose further increasing the content of octafluorotoluene.
In contrast, in the present invention, by using C 7F8 and using C 7F8 in combination with a predetermined etching gas or increasing the content of C 7F8, the silicon oxide film (SiO 2) can be selectively etched with respect to the Amorphous Carbon Layer (ACL).
And, by using C 7F8(GWP100 =4665) instead of C-C 4F8(GWP100＝9540)、CHF3(GWP100 =12400), and the like, also contributes to prevention of global warming.
1. Etching gas (first mode)
The etching gas according to the first embodiment of the present invention (particularly, the dry etching gas) contains C 7F8, and further contains C 7F7 H and/or C 6F5 H.
The C 7F8 used in the etching gas according to the first embodiment of the present invention is not particularly limited, and any etching gas may be used. Specifically, octafluorotoluene, octafluoro-1, 3, 5-cycloheptatriene, 1,2,3,4, 5-pentafluoro-5- (1, 2-trifluoroethyl) cyclopent-1, 3-diene, 1,2,3,5,5-pentafluoro-4- (1, 2-trifluoroethyl) cyclopent-1, 3-diene, 1,2,4,5,5-pentafluoro-3- (1, 2-trifluoroethyl) cyclopent-1, 3-diene, 1, 2-difluoro-3- (trifluoromethyl) -4- (1, 2-trifluoroethyl) cyclobut-1, 3-diene, and the like can be cited. These C 7F8 may be used alone or in combination of 2 or more. Further, these C 7F8 may be known or commercially available ones.
In the etching gas according to the first aspect of the present invention, the total amount of the etching gas according to the first aspect of the present invention is preferably 0.01 to 99.9% by volume, and the content of C 7F8 may be 10 to 99.9% by volume, 20 to 99.9% by volume, 30 to 99.9% by volume, 40 to 99.9% by volume, 50 to 99.8% by volume, 60 to 99.7% by volume, 70 to 99.6% by volume, or the like, based on the total amount of the etching gas according to the first aspect of the present invention, from the viewpoint of the ratio (SiO 2/ACL) of the etching rate of the Amorphous Carbon Layer (ACL) to the etching rate of the silicon oxide film (SiO 2) or the like. For example, when the catalyst is used in combination with an inert gas to be described later, the content of C 7F8 is preferably small (for example, 40 to 70% by volume, preferably 42 to 60% by volume, etc.); when the catalyst is not used in combination with an inert gas, the content of C 7F8 is preferably large (for example, 60 to 99.7 vol%, preferably 70 to 99.6 vol%, more preferably 80 to 99.4 vol%, etc.). In the case where a plurality of types of C 7F8 are contained in the etching gas according to the first aspect of the present invention, the total amount is preferably within the above range.
The etching gas according to the first embodiment of the present invention contains C 7F7 H and/or C 6F5 H as another etching gas. Thus, the etching rate of the Amorphous Carbon Layer (ACL) can be easily adjusted, and the ratio (SiO 2/ACL) of the etching rate to the silicon oxide film (SiO 2) can be easily further improved.
In the case where C 6F5 H is contained as another etching gas, C 6F5 H is not particularly limited, and any isomer may be used. Specifically, there may be mentioned pentafluorobenzene, pentafluoro-1, 3, 5-cyclohexatriene, 1,2,3, 4-tetrafluoro-5- (fluoromethylene) cyclopent-1, 3-diene, 5- (difluoromethylene) -1,2, 3-trifluorocyclopent-1, 3-diene, 5- (difluoromethylene) -1,2, 4-trifluorocyclopent-1, 3-diene, 3- (difluoromethylene) -1, 2-difluoro-4- (fluoromethylene) cyclobut-1-ene, 3, 4-bis (difluoromethylene) -1-fluorocyclobut-1-ene and the like. These C 6F5 H may be used alone or in combination of 2 or more. As these C 6F5 H, known ones or commercially available ones can be used.
In the case where C 7F7 H is contained as another etching gas, C 7F7 H is not particularly limited, and any isomer may be used. Specifically, 2H-heptafluorotoluene, 3H-heptafluorotoluene, 4H-heptafluorotoluene, difluoromethylpentafluorobenzene, (E) -1- (1, 2-difluorovinyl) -2,3,4,5,5-pentafluorocyclopenta-1, 3-diene, (Z) -1- (1, 2-difluorovinyl) -2,3,4,5,5-pentafluorocyclopenta-1, 3-diene, 1- (2, 2-difluorovinyl) -2,3,4,5,5-pentafluorocyclopenta-1, 3-diene, 1,2,3, 5-tetrafluoro-4- (1, 2-trifluorovinyl) cyclopent-1, 3-diene, 2,3, 5-tetrafluoro-1- (1, 2-trifluorovinyl) cyclopent-1, 3-diene, 2,4,5,5-tetrafluoro-1- (1, 2-trifluoroethyl) cyclopent-1, 3-diene, 1,2,5,5-tetrafluoro-4- (1, 2-trifluoroethyl) cyclopent-1, 3-diene, (E) -2- (1, 2-difluorovinyl) -1,3,4,5,5-pentafluorocyclopenta-1, 3-diene, (Z) -2- (1, 2-difluorovinyl) -1,3,4,5,5-pentafluorocyclopenta-1, 3-diene, 2- (2, 2-difluorovinyl) -1,3,4,5,5-pentafluorocyclopenta-1, 3-diene, 1,2,5,5-tetrafluoro-3- (1, 2-trifluorovinyl) cyclopent-1, 3-diene, 1,2,4, 5-tetrafluoro-3- (1, 2-trifluoroethyl) cyclopent-1, 3-diene, 1,3, 5-tetrafluoro-2- (1, 2-trifluoroethyl) cyclopent-1, 3-diene, 1,4,5,5-tetrafluoro-2- (1, 2-trifluoroethyl) cyclopent-1, 3-diene 1- (difluoromethyl) -3, 4-difluoro-2- (1, 2-trifluoroethyl) cyclobut-1, 3-diene, 3-fluoro-1- (trifluoromethyl) -2- (1, 2-trifluoroethyl) cyclobut-1, 3-diene, 3-fluoro-2- (trifluoromethyl) -1- (1, 2-trifluoroethyl) cyclobut-1, 3-diene, (Z) -1- (1, 2-difluorovinyl) -3, 4-difluoro-2- (trifluoromethyl) cyclobut-1, 3-diene, (E) -1- (1, 2-difluorovinyl) -3, 4-difluoro-2- (trifluoromethyl) cyclobut-1, 3-diene, 1- (2, 2-difluorovinyl) -3, 4-difluoro-2- (trifluoromethyl) cyclobut-1, 3-diene, and the like. These C 7F7 H may be used alone or in combination of 2 or more. As these C 7F7 H, known ones or commercially available ones can be used.
In the etching gas according to the first aspect of the present invention, the total amount of the etching gas according to the first aspect of the present invention is preferably 0.01 to 30% by volume, more preferably 0.02 to 20% by volume, even more preferably 0.03 to 10% by volume, and particularly preferably 0.05 to 5% by volume, based on 100% by volume of the total amount of the etching gas according to the first aspect of the present invention, in terms of the ratio (SiO 2/ACL) between the etching rate of the Amorphous Carbon Layer (ACL) and the etching rate of the silicon oxide film (SiO 2), and the like. In the case where the etching gas according to the first embodiment of the present invention contains a plurality of types of C 7F7 H and/or C 6F5 H, the total amount thereof is preferably within the above range.
The effect can be provided by adding another etching gas to the etching gas according to the first aspect of the present invention.
As another etching gas, for example, when a hydrofluorocarbon compound (HFC) such as CF2H2、C2F2H2、C2F2H4、C3F4H2 is added, the etching rate of the Amorphous Carbon Layer (ACL) can be adjusted; when a perfluorocarbon compound (PFC) such as CF4、C2F6、C3F8、C4F8、C3F6、C4F6、C5F8 is added, the etching rate of the silicon oxide film (SiO 2) can be adjusted. Further, when iodide such as CF 3I、C2F5I、C3F7 I is added, the etching rate of the silicon oxide film (SiO 2) can be adjusted, and the electron temperature of the plasma can be reduced because dissociation is easy, and thus the etching rate of the Amorphous Carbon Layer (ACL) can be increased, and the ratio (SiO 2/ACL) between the etching rate of the Amorphous Carbon Layer (ACL) and the etching rate of the silicon oxide film (SiO 2) can be easily increased. These other etching gases may be used alone or in combination of 2 or more. Further, these other etching gases may be known or commercially available ones. The other etching gas is not limited as long as it can be used for etching.
When the etching gas according to the first aspect of the present invention contains another etching gas, the total amount of the etching gas according to the first aspect of the present invention is set to 100% by volume, and the content of the other etching gas is preferably 0.01 to 30% by volume, more preferably 0.02 to 20% by volume, still more preferably 0.03 to 10% by volume, and particularly preferably 0.05 to 5% by volume, from the viewpoint of the ratio (SiO 2/ACL) between the etching rate of the Amorphous Carbon Layer (ACL) and the etching rate of the silicon oxide film (SiO 2). In the case where the etching gas according to the first aspect of the present invention contains a plurality of other etching gases, the total amount thereof is preferably within the above-described range.
The etching gas according to the first aspect of the present invention may contain an oxygen compound.
By containing an oxygen compound in the etching gas according to the first embodiment of the present invention, the ratio (SiO 2/ACL) between the etching rate of the Amorphous Carbon Layer (ACL) and the etching rate of the silicon oxide film (SiO 2) can be easily increased. In the case where the etching gas according to the first aspect of the present invention contains the other etching gas, it is particularly preferable to contain an oxygen compound.
Examples of the oxygen compound include O 2、O3、NO、N2O、NO2、SO2、COS、CO、CO2、H2 O (water). These oxygen compounds may be used alone or in combination of 2 or more. Among them, O 2 is preferable from the viewpoint of increasing the ratio (SiO 2/ACL) of the etching rate of the Amorphous Carbon Layer (ACL) to the etching rate of the silicon oxide film (SiO 2) by a small amount.
When the etching gas according to the first aspect of the present invention contains an oxygen compound, the total amount of the etching gas according to the first aspect of the present invention is preferably 0 to 20% by volume, more preferably 0.01 to 15% by volume, still more preferably 0.1 to 10% by volume, and particularly preferably 1 to 7% by volume. In the case where the etching gas according to the first aspect of the present invention contains a plurality of oxygen compounds, the total amount thereof is preferably within the above-described range. Thereby, siO 2/ACL can be increased. In addition, the etching rate can be easily adjusted by setting the content of the oxygen compound to 0 to 20% by volume.
When H 2 O (water) is contained as the oxygen compound, the total amount of the etching gas according to the first embodiment of the present invention is set to 100% by volume, and the content of H 2 O (water) is preferably 0.01 to 200 ppm by volume, more preferably 0.1 to 150 ppm by volume, and still more preferably 1 to 100 ppm by volume. Thus, the ratio (SiO 2/ACL) between the etching rate of the Amorphous Carbon Layer (ACL) and the etching rate of the silicon oxide film (SiO 2) can be further increased. The content of H 2 O (water) in the etching gas according to the first embodiment of the present invention is measured by a karl fischer moisture meter.
The etching gas according to the first aspect of the present invention may contain an inert gas as necessary.
The inert gas may be 1 or 2 or more kinds of rare gas, nitrogen gas, or the like, and the rare gas may be helium, neon, argon, xenon, krypton, or the like, and is preferably a rare gas, more preferably argon, from the viewpoint of the ratio (SiO 2/ACL) of the etching rate of the Amorphous Carbon Layer (ACL) to the etching rate of the silicon oxide film (SiO 2), or the like. These inert gases may be used alone or in combination of 2 or more. Further, these inert gases may be used as known products or commercially available products.
These inert gases can change the electron temperature and electron density of the plasma, can control the balance of fluorocarbon radicals and fluorocarbon ions, can adjust the etching rate of the silicon oxide film (SiO 2 film), and can increase the ratio (SiO 2/ACL) of the etching rate of the Amorphous Carbon Layer (ACL) to the etching rate of the silicon oxide film (SiO 2).
When the etching gas according to the first aspect of the present invention contains an inert gas, the total amount of the etching gas according to the first aspect of the present invention is set to 100% by volume, and the inert gas content is preferably 1 to 60% by volume, more preferably 10 to 58% by volume, still more preferably 20 to 57% by volume, and particularly preferably 30 to 55% by volume. In the case where the etching gas according to the first aspect of the present invention contains a plurality of inert gases, the total amount thereof is preferably within the above-described range. Thus, the ratio (SiO 2/ACL) of the etching rate of the Amorphous Carbon Layer (ACL) to the etching rate of the silicon oxide film (SiO 2) can be increased.
The etching gas according to the first aspect of the present invention may further contain the following additional gases.
The gas containing F 2、NF3 or the like as a fluorine source can partially fluorinate the CH 2 segment to form CHF, CF 2 or the like, thereby improving the etching rate.
In addition, by containing H 2 or NH 3, a good etching shape can be obtained.
The content of these additional gas components is preferably within a range that does not impair the effects of the present invention, and for example, the total amount of the etching gas according to the first embodiment of the present invention is set to 100% by volume, preferably 0 to 10% by volume, and particularly 0 to 5% by volume.
A preferred etching gas and its volume according to the first embodiment of the present invention are as follows.
·C7F8/C7F7H
60 To 99.7% by volume (preferably 70 to 99.6% by volume, more preferably 80 to 99.4% by volume) per 0.3 to 40% by volume (preferably 0.4 to 30% by volume, more preferably 0.6 to 20% by volume).
·C7F8/C7F7H/O2
60 To 99.7% by volume (preferably 70 to 99.6% by volume, more preferably 80 to 99.4% by volume) per 0.02 to 20% by volume (preferably 0.03 to 10% by volume, more preferably 0.05 to 5% by volume) per 0.01 to 15% by volume (preferably 0.1 to 10% by volume, more preferably 1 to 7% by volume).
·C7F8/C7F7H/O2/Ar
40 To 70% (preferably 41 to 65%, more preferably 42 to 60%) by volume/0.02 to 20% (preferably 0.03 to 10%, more preferably 0.05 to 5%) by volume/0.01 to 15% (preferably 0.1 to 10%, more preferably 1 to 7%) by volume/10 to 58% (preferably 20 to 57%, more preferably 30 to 55%).
·C7F8/C6F5H
60 To 99.7% by volume (preferably 70 to 99.6% by volume, more preferably 80 to 99.4% by volume) per 0.3 to 40% by volume (preferably 0.4 to 30% by volume, more preferably 0.6 to 20% by volume).
·C7F8/C6F5H/O2
60 To 99.7% by volume (preferably 70 to 99.6% by volume, more preferably 80 to 99.4% by volume) per 0.02 to 20% by volume (preferably 0.03 to 10% by volume, more preferably 0.05 to 5% by volume) per 0.01 to 15% by volume (preferably 0.1 to 10% by volume, more preferably 1 to 7% by volume).
·C7F8/C6F5H/O2/Ar
40 To 70% (preferably 41 to 65%, more preferably 42 to 60%) by volume/0.02 to 20% (preferably 0.03 to 10%, more preferably 0.05 to 5%) by volume/0.01 to 15% (preferably 0.1 to 10%, more preferably 1 to 7%) by volume/10 to 58% (preferably 20 to 57%, more preferably 30 to 55%).
As described above, the etching gas according to the first aspect of the present invention satisfying such conditions is an etching gas capable of etching the silicon oxide film (SiO 2) selectively to the Amorphous Carbon Layer (ACL), and therefore can be used for etching a silicon-based material including the silicon oxide film (SiO 2 film) having the Amorphous Carbon Layer (ACL) formed on the entire surface or a part of the surface. Specifically, the ratio (SiO 2/ACL) of the etching rate of the Amorphous Carbon Layer (ACL) to the etching rate of the silicon oxide film (SiO 2) is preferably 3.0 or more, more preferably 3.0 to 5.0, and still more preferably 3.1 to 4.0.
The ratio (SiO 2/ACL) of the etching rate of the Amorphous Carbon Layer (ACL) to the etching rate of the silicon oxide film (SiO 2) can be adjusted by the content of C 7F8, the kind of other etching gas and the content thereof, the content of the oxygen compound, the content of the inert gas, and the like. In particular, the content of the oxygen compound can be easily adjusted by reducing the content to, for example, 0 to 20% by volume.
2. Etching gas (second mode)
The etching gas (particularly, dry etching gas) according to the second aspect of the present invention contains C 7F8 to 99.9% by volume, based on 100% by volume of the total etching gas.
As C 7F8 used in the etching gas according to the second aspect of the present invention, C 7F8 described in the first aspect can be used. The same applies to preferred embodiments.
The etching gas according to the second aspect of the present invention is such that the total amount of the etching gas according to the second aspect of the present invention is 100% by volume, and the content of C 7F8 is 60 to 99.9% by volume, preferably 70 to 99.6% by volume, and more preferably 80 to 99.4% by volume. When the content of C 7F8 in the etching gas according to the second aspect of the present invention is less than 60% by volume, the silicon oxide film (SiO 2) cannot be selectively etched with respect to the Amorphous Carbon Layer (ACL). In the case where a plurality of types of C 7F8 are contained in the etching gas according to the second aspect of the present invention, the total amount is preferably within the above range.
The effect can be imparted by adding C 7F7H、C6F5 H, another etching gas, or the like to the etching gas according to the second aspect of the present invention. The etching gas according to the second aspect of the present invention may contain an oxygen compound, an inert gas, an additive gas, or the like.
As the C 7F7H、C6F5 H, other etching gases, oxygen compounds, inert gases, and additional gases used in the etching gas according to the second aspect of the present invention, the ones described in the above first aspect can be used. The preferred specific examples and contents are also the same.
A preferred etching gas and its volume according to the second aspect of the present invention are as follows.
·C7F8/C7F7H
60 To 99.9% by volume (preferably 70 to 99.6% by volume, more preferably 80 to 99.4% by volume) per 0.1 to 40% by volume (preferably 0.4 to 30% by volume, more preferably 0.6 to 20% by volume).
·C7F8/C7F7H/O2
60 To 99.9% by volume (preferably 70 to 99.6% by volume, more preferably 80 to 99.4% by volume) per 0.02 to 20% by volume (preferably 0.03 to 10% by volume, more preferably 0.05 to 5% by volume) per 0.01 to 15% by volume (preferably 0.1 to 10% by volume, more preferably 1 to 7% by volume).
·C7F8/C6F5H
60 To 99.9% by volume (preferably 70 to 99.6% by volume, more preferably 80 to 99.4% by volume) per 0.3 to 40% by volume (preferably 0.4 to 30% by volume, more preferably 0.6 to 20% by volume).
·C7F8/C6F5H/O2
60 To 99.9% by volume (preferably 70 to 99.6% by volume, more preferably 80 to 99.4% by volume) per 0.02 to 20% by volume (preferably 0.03 to 10% by volume, more preferably 0.05 to 5% by volume) per 0.01 to 15% by volume (preferably 0.1 to 10% by volume, more preferably 1 to 7% by volume).
As described above, the etching gas according to the second aspect of the present invention satisfying such conditions is an etching gas capable of etching the silicon oxide film (SiO 2) selectively to the Amorphous Carbon Layer (ACL), and therefore can be used for etching a silicon-based material including the silicon oxide film (SiO 2 film) having the Amorphous Carbon Layer (ACL) formed on the entire surface or a part of the surface. Specifically, the ratio (SiO 2/ACL) of the etching rate of the Amorphous Carbon Layer (ACL) to the etching rate of the silicon oxide film (SiO 2) is preferably 3.0 or more, more preferably 3.0 to 5.0, and still more preferably 3.1 to 4.0.
The ratio (SiO 2/ACL) of the etching rate of the Amorphous Carbon Layer (ACL) to the etching rate of the silicon oxide film (SiO 2) can be adjusted by the content of C 7F8, the kind of other etching gas and the content thereof, the content of the oxygen compound, the content of the inert gas, and the like. In particular, the content of the oxygen compound can be easily adjusted by reducing the content to, for example, 0 to 20% by volume.
3. Etching method
By using the gas plasma of the etching gas of the present invention, a silicon-based material including a silicon oxide film (SiO 2 film) having an Amorphous Carbon Layer (ACL) formed on the entire surface or a part of the surface can be etched. The etching method (in particular, the dry etching method) may be performed under the same conditions as in the conventional method except that the etching gas of the present invention is used.
The etching conditions may be set as follows:
The flow rate is 5-2000 sccm, preferably 10-1000 sccm;
the discharge power is 200-20000W, preferably 400-10000W;
bias power 25-15000W, preferably 100-10000W;
the pressure is 30mTorr or less (3.99 Pa or less), preferably 2-10 mTorr (0.266-1.33 Pa);
Electron density 10 9～1013cm-3, preferably 10 10～1012cm-3;
Electron temperature 2-9 eV, preferably 3-8 eV;
the wafer temperature is-40-100 ℃, preferably-30-50 ℃;
the chamber wall temperature is-30 to 300 ℃, preferably 20 to 200 ℃.
The pressure means gauge pressure unless otherwise specified.
In addition, the discharge power and the bias power are different depending on the size of the chamber, the size of the electrode, and the like. The preferable etching conditions for etching the pattern of the contact hole or the like on the silicon oxide film or the like by using the Inductively Coupled Plasma (ICP) etching apparatus for small diameter wafers (chamber volume 3500cm 3) can be set as follows:
The discharge power is 200-1000W, preferably 300-600W;
bias power is 50-500W, preferably 100-300W.
The embodiments of the present invention have been described above, and various modifications may be made in the modes and details without departing from the spirit and scope of the invention as claimed.
Examples
Hereinafter, the present invention will be described specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.
Examples 1 to 5 and comparative examples 1 to 2
Under the etching conditions of ICP (Inductive Coupled Plasma, inductively coupled plasma), discharge power 1000W, bias power 300W, pressure 10mTorr, electron density 8×10 10～2×1011cm-3, and electron temperature 5 to 7eV, the etching rates of a 1000 μm thick silicon oxide (SiO 2) film (SiO 2) formed on a silicon substrate and a 5000 μm thick amorphous carbon film (ACL) formed on a silicon substrate were measured, and the ratio of the etching rates of the SiO 2 film and the ACL film at this time was regarded as a ratio to ACL selection (etching rate of SiO 2 film/etching rate of ACL film). Among them, the SiO 2 film was formed according to a conventional method, and the ACL film was formed according to the reported (registered trademark) APF TM PECVD-APPLIED MATERIALS. The results are shown in Table 1. The water content measured using a karl fischer moisture meter is also shown in table 1.
In table 1, C7F8 represents octafluorotoluene, C7F7H represents hexafluorotoluene, and C6F5H represents pentafluoroethylene.
TABLE 1
Claims (7)
1. An etching gas, characterized in that,
Contains C 7F8, and also contains C 7F7 H and/or C 6F5 H.
2. An etching gas, characterized in that,
The total amount of the etching gas is set to 100% by volume, and C 7F8 is contained in an amount of 60 to 99.9% by volume.
3. The etching gas according to claim 1 or 2, wherein,
Also contains oxygen compound.
4. The etching gas of claim 3,
The oxygen compound contains water.
5. The etching gas of claim 4,
The total amount of the etching gas is set to 100 vol% and the water content is set to 0.01 to 200 vol ppm.
6. The etching gas according to claim 1to 5, wherein,
And also contains inert gas.
7. An etching method, characterized in that,
A silicon material comprising a silicon oxide film (SiO 2 film) having an Amorphous Carbon Layer (ACL) formed on the entire surface or a part of the surface thereof is etched by using the gas plasma of the etching gas according to any one of claims 1 to 6.
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| JP2021-178863 | 2021-11-01 | ||
| PCT/JP2022/039026 WO2023074511A1 (en) | 2021-11-01 | 2022-10-20 | Etching gas and etching method using same |
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| JP2006049771A (en) * | 2004-08-09 | 2006-02-16 | Tokyo Electron Ltd | Etching gas, etching method, and method for estimating etching gas |
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