WO2010050520A1 - Euvリソグラフィ用反射型マスクブランク - Google Patents
Euvリソグラフィ用反射型マスクブランク Download PDFInfo
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- WO2010050520A1 WO2010050520A1 PCT/JP2009/068519 JP2009068519W WO2010050520A1 WO 2010050520 A1 WO2010050520 A1 WO 2010050520A1 JP 2009068519 W JP2009068519 W JP 2009068519W WO 2010050520 A1 WO2010050520 A1 WO 2010050520A1
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- layer
- mask blank
- low
- reflective
- reflective layer
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- 238000001900 extreme ultraviolet lithography Methods 0.000 title claims abstract description 40
- 238000000034 method Methods 0.000 claims abstract description 82
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 48
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 45
- 239000000758 substrate Substances 0.000 claims abstract description 45
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 36
- 239000001257 hydrogen Substances 0.000 claims abstract description 36
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 29
- 239000001301 oxygen Substances 0.000 claims abstract description 29
- 229910052715 tantalum Inorganic materials 0.000 claims abstract description 25
- 238000004519 manufacturing process Methods 0.000 claims abstract description 21
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 claims abstract description 15
- 239000010410 layer Substances 0.000 claims description 380
- 239000006096 absorbing agent Substances 0.000 claims description 116
- 238000007689 inspection Methods 0.000 claims description 59
- 239000011241 protective layer Substances 0.000 claims description 44
- 229910052757 nitrogen Inorganic materials 0.000 claims description 33
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 28
- 238000004544 sputter deposition Methods 0.000 claims description 25
- 229910052786 argon Inorganic materials 0.000 claims description 22
- 239000000203 mixture Substances 0.000 claims description 22
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 20
- 230000003746 surface roughness Effects 0.000 claims description 14
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 12
- 239000011261 inert gas Substances 0.000 claims description 12
- 229910052710 silicon Inorganic materials 0.000 claims description 12
- 239000010703 silicon Substances 0.000 claims description 12
- 239000004065 semiconductor Substances 0.000 claims description 11
- 239000001307 helium Substances 0.000 claims description 10
- 229910052734 helium Inorganic materials 0.000 claims description 10
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 claims description 10
- 229910052743 krypton Inorganic materials 0.000 claims description 10
- DNNSSWSSYDEUBZ-UHFFFAOYSA-N krypton atom Chemical compound [Kr] DNNSSWSSYDEUBZ-UHFFFAOYSA-N 0.000 claims description 10
- 229910052754 neon Inorganic materials 0.000 claims description 10
- GKAOGPIIYCISHV-UHFFFAOYSA-N neon atom Chemical compound [Ne] GKAOGPIIYCISHV-UHFFFAOYSA-N 0.000 claims description 10
- 229910052724 xenon Inorganic materials 0.000 claims description 10
- FHNFHKCVQCLJFQ-UHFFFAOYSA-N xenon atom Chemical compound [Xe] FHNFHKCVQCLJFQ-UHFFFAOYSA-N 0.000 claims description 10
- 239000013078 crystal Substances 0.000 claims description 9
- 229910052796 boron Inorganic materials 0.000 claims description 6
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims description 4
- 229910052732 germanium Inorganic materials 0.000 claims description 3
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 claims description 3
- 229910052735 hafnium Inorganic materials 0.000 claims description 3
- VBJZVLUMGGDVMO-UHFFFAOYSA-N hafnium atom Chemical compound [Hf] VBJZVLUMGGDVMO-UHFFFAOYSA-N 0.000 claims description 3
- VSZWPYCFIRKVQL-UHFFFAOYSA-N selanylidenegallium;selenium Chemical compound [Se].[Se]=[Ga].[Se]=[Ga] VSZWPYCFIRKVQL-UHFFFAOYSA-N 0.000 claims description 3
- 238000012546 transfer Methods 0.000 abstract description 10
- 238000002310 reflectometry Methods 0.000 abstract description 8
- 239000007789 gas Substances 0.000 description 75
- 239000000463 material Substances 0.000 description 27
- 238000000151 deposition Methods 0.000 description 20
- 230000008021 deposition Effects 0.000 description 19
- 238000005259 measurement Methods 0.000 description 15
- 239000011521 glass Substances 0.000 description 14
- 230000015572 biosynthetic process Effects 0.000 description 12
- 230000007547 defect Effects 0.000 description 12
- 238000005530 etching Methods 0.000 description 12
- 238000003795 desorption Methods 0.000 description 11
- 238000001755 magnetron sputter deposition Methods 0.000 description 10
- 239000011248 coating agent Substances 0.000 description 8
- 238000000576 coating method Methods 0.000 description 8
- 150000001875 compounds Chemical class 0.000 description 8
- 238000001659 ion-beam spectroscopy Methods 0.000 description 8
- 229910003071 TaON Inorganic materials 0.000 description 6
- 239000011651 chromium Substances 0.000 description 6
- 238000000206 photolithography Methods 0.000 description 6
- 230000007261 regionalization Effects 0.000 description 6
- 229910052707 ruthenium Inorganic materials 0.000 description 6
- 229910004298 SiO 2 Inorganic materials 0.000 description 5
- 230000031700 light absorption Effects 0.000 description 5
- 238000000059 patterning Methods 0.000 description 5
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 4
- 239000000460 chlorine Substances 0.000 description 4
- 229910052801 chlorine Inorganic materials 0.000 description 4
- 238000001312 dry etching Methods 0.000 description 4
- 238000011156 evaluation Methods 0.000 description 4
- 150000002431 hydrogen Chemical class 0.000 description 4
- -1 hydrogen ions Chemical class 0.000 description 4
- 150000002500 ions Chemical class 0.000 description 4
- 239000012528 membrane Substances 0.000 description 4
- 238000005001 rutherford backscattering spectroscopy Methods 0.000 description 4
- 229910000521 B alloy Inorganic materials 0.000 description 3
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 3
- 229910019895 RuSi Inorganic materials 0.000 description 3
- 229910010413 TiO 2 Inorganic materials 0.000 description 3
- XTDAIYZKROTZLD-UHFFFAOYSA-N boranylidynetantalum Chemical compound [Ta]#B XTDAIYZKROTZLD-UHFFFAOYSA-N 0.000 description 3
- 229910052804 chromium Inorganic materials 0.000 description 3
- 238000004140 cleaning Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 2
- 238000002441 X-ray diffraction Methods 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 230000001133 acceleration Effects 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 238000007687 exposure technique Methods 0.000 description 2
- 229910052731 fluorine Inorganic materials 0.000 description 2
- 239000011737 fluorine Substances 0.000 description 2
- 238000007654 immersion Methods 0.000 description 2
- 238000001459 lithography Methods 0.000 description 2
- 150000004767 nitrides Chemical class 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 229910004162 TaHf Inorganic materials 0.000 description 1
- 229910004200 TaSiN Inorganic materials 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
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- 238000007599 discharging Methods 0.000 description 1
- 238000009713 electroplating Methods 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 238000001579 optical reflectometry Methods 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 238000001020 plasma etching Methods 0.000 description 1
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- 238000004439 roughness measurement Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000005477 sputtering target Methods 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- 239000011135 tin Substances 0.000 description 1
- 238000001771 vacuum deposition Methods 0.000 description 1
- 238000001039 wet etching Methods 0.000 description 1
- 229910000500 β-quartz Inorganic materials 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F1/00—Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
- G03F1/68—Preparation processes not covered by groups G03F1/20 - G03F1/50
- G03F1/82—Auxiliary processes, e.g. cleaning or inspecting
- G03F1/84—Inspecting
- G03F1/86—Inspecting by charged particle beam [CPB]
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F1/00—Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
- G03F1/22—Masks or mask blanks for imaging by radiation of 100nm or shorter wavelength, e.g. X-ray masks, extreme ultraviolet [EUV] masks; Preparation thereof
- G03F1/24—Reflection masks; Preparation thereof
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y10/00—Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y40/00—Manufacture or treatment of nanostructures
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F1/00—Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
- G03F1/38—Masks having auxiliary features, e.g. special coatings or marks for alignment or testing; Preparation thereof
- G03F1/46—Antireflective coatings
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F1/00—Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
- G03F1/54—Absorbers, e.g. of opaque materials
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F1/00—Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
- G03F1/68—Preparation processes not covered by groups G03F1/20 - G03F1/50
-
- 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
- H01L21/027—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34
- H01L21/0271—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34 comprising organic layers
- H01L21/0273—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34 comprising organic layers characterised by the treatment of photoresist layers
- H01L21/0274—Photolithographic processes
- H01L21/0275—Photolithographic processes using lasers
Definitions
- the present invention relates to a reflective mask blank for EUV (Extreme Ultra Violet) lithography (hereinafter referred to as “EUV mask blank” in the present specification) used in semiconductor manufacturing and the like.
- EUV mask blank Extreme Ultra Violet
- a photolithography method using visible light or ultraviolet light has been used as a technique for transferring a fine pattern necessary for forming an integrated circuit having a fine pattern on a Si substrate or the like.
- the limits of conventional photolithography methods have been approached.
- the resolution limit of the pattern is about 1 ⁇ 2 of the exposure wavelength, and it is said that the immersion wavelength is about 1 ⁇ 4 of the exposure wavelength, and the immersion of ArF laser (193 nm) is used. Even if the method is used, the limit of about 45 nm is expected.
- EUV lithography which is an exposure technique using EUV light having a wavelength shorter than that of an ArF laser, is promising as an exposure technique for 45 nm and beyond.
- EUV light refers to light having a wavelength in the soft X-ray region or the vacuum ultraviolet region, and specifically refers to light having a wavelength of about 10 to 20 nm, particularly about 13.5 nm ⁇ 0.3 nm.
- a conventional refractive optical system such as photolithography using visible light or ultraviolet light may be used. Can not. For this reason, in the EUV light lithography, a reflective optical system, that is, a reflective photomask and a mirror are used.
- the mask blank is a layered product before patterning used for manufacturing a photomask.
- a reflective layer that reflects EUV light and an absorber layer that absorbs EUV light are formed in this order on a substrate such as glass.
- a multilayer reflective film is generally used in which a high refractive layer and a low refractive layer are alternately laminated to increase the light reflectivity when EUV light is irradiated onto the layer surface.
- the absorber layer a material having a high absorption coefficient for EUV light, specifically, for example, a material mainly composed of Ta or Cr is used.
- a low reflection layer for mask pattern inspection light is usually provided on the absorber layer of the EUV mask blank.
- light in the wavelength region of deep ultraviolet light 190 to 260 nm
- the reflectance difference between the region where the low reflection layer and the absorber layer are removed by the patterning process and the region where the low reflection layer and the absorber layer remain, that is, The presence or absence of pattern defects is inspected by the contrast of reflected light on the surfaces of these regions.
- the low reflection layer has low reflection characteristics with respect to the above wavelength range, that is, with respect to the above wavelength range. It is usually required that the reflectivity be 15% or less.
- Patent Document 1 a low reflective layer made of a tantalum boron alloy oxide (TaBO) or a tantalum boron alloy oxynitride (TaBNO) is formed on an absorber layer made of a tantalum boron alloy nitride (TaBN).
- TaBO tantalum boron alloy oxide
- TaBNO tantalum boron alloy oxynitride
- Patent Document 2 discloses that metal, silicon (Si), oxygen (O) and nitrogen (N) are formed on the absorber layer in order to adjust the reflectance of the mask pattern with respect to the wavelength range (190 nm to 260 nm) of the inspection light. It is preferable to provide a low reflection layer made of
- JP 2004-6798 A (US Pat. No. 7,390,596) JP 2006-228767 A
- Patent Document 1 and Patent Document 2 when the low reflection layer is a TaBO film or TaBNO film, a material made of metal, silicon (Si), oxygen (O), and nitrogen (N) (for example, TaSiON, ZrSiON, etc.) It is described that sufficient contrast is obtained for the wavelength 257 nm of the inspection light of the mask pattern currently used. However, in the mask manufacturing process and the pattern transfer process, not only the reflectance at the mask pattern inspection wavelength (190 to 260 nm) but also the reflectance to the wavelength of 400 to 1200 nm is important.
- Light having a wavelength of 400 to 1200 nm is usually used as a “position sensor” during mask transportation and handling, and if it is not in the desired reflectance range, the substrate position accuracy deteriorates, that is, the pattern accuracy deteriorates. May occur.
- the reflectance with respect to the wavelength of the light used as the position sensor varies depending on the apparatus used in each process (inspection, pattern drawing, etching, exposure), but in general, “less than 40% at 405 nm”, “600 ⁇ “30 to 50% at 650 nm”, “greater than 50% at 800 to 900 nm”, and “less than 90% at 1000 to 1200 nm” are often required.
- the present invention has excellent characteristics as an EUV mask blank, that is, has a low reflectance with respect to the wavelength region (190 to 260 nm) of the EUV light and the inspection light of the mask pattern, and
- An object of the present invention is to provide an EUV mask blank having a low reflection layer capable of satisfying the above desired reflectance in a wavelength range (400 to 1200 nm) required in a mask manufacturing process and a pattern transfer process.
- the low reflection layer is a film containing at least tantalum (Ta), oxygen (O), and hydrogen (H) (hereinafter referred to as “TaOH film”).
- a film containing at least Ta, N, O, and H (hereinafter referred to as a “TaONH film”) has low reflection characteristics with respect to EUV light and mask pattern inspection light (wavelength 190 to 260 nm).
- the present inventors have found that the desired reflectance can be satisfied in a wavelength region (400 to 1200 nm) required for a mask manufacturing process and a pattern transfer process.
- a reflective layer that reflects EUV light On the substrate, a reflective layer that reflects EUV light, an absorber layer that absorbs EUV light, and mask pattern inspection light (wavelength 190 to 260 nm).
- the total content of Ta and O is 85 to 99.9 at% (atomic percentage, the same applies hereinafter), and the content of H is 0.1 to 15 at%
- the EUV mask blank of the present invention is provided.
- the composition ratio means an atomic ratio.
- the EUV blank of the present invention includes a reflective layer for reflecting EUV light, an absorber layer for absorbing EUV light, and a low reflective layer for mask pattern inspection light (wavelength 190 to 260 nm) on a substrate.
- a reflective mask blank for EUV lithography formed in order, The low reflection layer contains at least tantalum (Ta), oxygen (O), nitrogen (N) and hydrogen (H);
- the low reflection layer (TaONH film) has a total content of Ta, O and N of 85 to 99.9 at% and a content of H of 0.1 to 15 at%
- a reflective mask blank is provided.
- the low reflection layer (TaOH film and TaONH film) preferably has a surface roughness (rms) of 0.5 nm or less.
- the crystal structure of the low reflective layer (TaOH film and TaONH film) is preferably amorphous.
- the film thickness of the low reflective layer is preferably 3 to 30 nm.
- the absorber layer is preferably an absorber layer containing tantalum (Ta) as a main component.
- the absorber layer contains tantalum (Ta) as a main component, hafnium (Hf), silicon (Si), zirconium (Zr), germanium (Ge), boron (B), nitrogen ( N) and at least one element selected from hydrogen (H) may be included.
- the absorber layer preferably has an oxygen (O) content of less than 25 at%.
- the absorber layer and the low reflection layer preferably have a thickness of 30 to 200 nm.
- a protective layer for protecting the reflective layer is formed between the reflective layer and the absorber layer when forming a pattern on the absorber layer
- the contrast between the reflected light on the surface of the protective layer and the reflected light on the surface of the low reflective layer (TaOH film and TaONH film) with respect to the wavelength (190 to 260 nm) of the inspection light of the mask pattern is 60% or more.
- the hydrogen content in the low reflection layer is preferably 1 at% or more higher than the hydrogen content in the absorber layer.
- the reflectance of the surface of the low reflection layer (TaOH film and TaONH film) with respect to the wavelength (190 to 260 nm) of the inspection light of the mask pattern is preferably 15% or less.
- the low reflective layer contains at least one of helium (He), argon (Ar), neon (Ne), krypton (Kr), and xenon (Xe). It is preferably formed by performing a sputtering method using a Ta target in an atmosphere containing gas, oxygen (O), and hydrogen (H).
- the low reflective layer is an inert material containing at least one of helium (He), argon (Ar), neon (Ne), krypton (Kr), and xenon (Xe). It is preferably formed by performing a sputtering method using a Ta target in an atmosphere containing a gas and oxygen (O), nitrogen (N), and hydrogen (H).
- a reflective layer that reflects EUV light, an absorber layer that absorbs EUV light, and a low reflective layer for mask pattern inspection light are formed in this order on the substrate.
- a method of manufacturing a reflective mask blank for EUV lithography The low reflective layer includes an inert gas containing at least one of helium (He), argon (Ar), neon (Ne), krypton (Kr), and xenon (Xe), oxygen (O), and hydrogen (H).
- a reflective mask blank for EUV lithography characterized by being formed by performing a sputtering method using a Ta target in an atmosphere containing benzene.
- a reflective layer that reflects EUV light, an absorber layer that absorbs EUV light, and a low reflective layer for mask pattern inspection light are formed in this order on the substrate.
- a method of manufacturing a reflective mask blank for EUV lithography The low reflective layer includes an inert gas containing at least one of helium (He), argon (Ar), neon (Ne), krypton (Kr), and xenon (Xe), oxygen (O), and nitrogen (N).
- a reflective mask blank for EUV lithography which is formed by performing a sputtering method using a Ta target in an atmosphere containing hydrogen (H).
- the present invention also provides a reflective mask for EUV lithography, wherein the absorber layer and the low reflective layer of the reflective mask blank for EUV lithography of the present invention are patterned.
- the present invention also provides a method for manufacturing a semiconductor integrated circuit, characterized in that a semiconductor integrated circuit is manufactured by exposing an object to be exposed using the reflective mask for EUV lithography of the present invention.
- the EUV mask blank of the present invention has a low reflectance in the wavelength range (190 to 260 nm) of the EUV light and the inspection light of the mask pattern, and also has a wavelength range (400 ⁇ 1200 nm) to satisfy a desired reflectance (405 nm: ⁇ 40%, 600-650 nm: 30-50%, 800-900 nm:> 50%, 1000-1200 nm: ⁇ 90%).
- the manufacturing process and the pattern transfer process have the advantage of being stabilized.
- FIG. 1 is a schematic cross-sectional view showing an embodiment of the EUV mask blank of the present invention.
- FIG. 2 shows a state where the absorber layer 14 and the low reflection layer 15 of the EUV mask blank 1 shown in FIG. 1 are patterned.
- FIG. 1 is a schematic cross-sectional view showing an embodiment of the EUV mask blank of the present invention.
- a reflective layer 12 that reflects EUV light and an absorber layer 14 that absorbs EUV light are formed on a substrate 11 in this order.
- a protective layer 13 is formed between the reflective layer 12 and the absorber layer 14 to protect the reflective layer 12 when forming a pattern on the absorber layer 14.
- On the absorber layer 14, a low reflection layer 15 for the inspection light of the mask pattern is formed.
- the protective layer 13 is an optional component. .
- individual components of the mask blank 1 will be described.
- the substrate 11 is required to satisfy the characteristics as a substrate for an EUV mask blank. Therefore, the substrate 11, the low thermal expansion coefficient (specifically, it is preferable that the thermal expansion coefficient at 20 ° C. is 0 ⁇ 0.05 ⁇ 10 -7 / °C , particularly preferably 0 ⁇ 0.03 ⁇ 10 - 7 / ° C.) and excellent in smoothness, flatness, and resistance to a cleaning liquid used for cleaning a mask blank or a photomask after pattern formation.
- the substrate 11 is made of glass having a low thermal expansion coefficient, such as SiO 2 —TiO 2 glass, but is not limited to this. Crystallized glass, quartz glass, silicon or the like on which ⁇ quartz solid solution is precipitated is used. A substrate made of metal or the like can also be used.
- the hydrogen molecule concentration is 1 ⁇ 10 16 molecules / cm 3 , 5 ⁇ 10 16 molecules / cm 3 , 1 ⁇ 10 17 molecules / in terms of the cleaning effect of carbon contamination and the reduction effect of the oxidized film.
- it is cm 3 , 5 ⁇ 10 17 molecules / cm 3 or more.
- the hydrogen molecule concentration is 1 ⁇ 10 18 molecules / cm 3 or more, more preferably 5 ⁇ 10 18 molecules / cm 3 or more, and particularly preferably 1 ⁇ 10 19 molecules / cm 3 or more.
- it is preferably 5 ⁇ 10 19 molecules / cm 3 or more.
- the measurement of the hydrogen molecule concentration is preferably performed as follows using a thermal desorption spectrometer (TDS) manufactured by Electronic Science Co., Ltd. based on Japanese Patent No. 3298974.
- TDS thermal desorption spectrometer
- a glass sample into which hydrogen molecules have been introduced is placed in a thermal desorption analyzer, the inside of the measurement chamber is evacuated to 5 ⁇ 10 ⁇ 7 Pa or less, the glass sample is heated, and the mass number of the generated gas is analyzed Measure with an internal mass spectrometer.
- TDS thermal desorption spectrometer
- a peak is observed around 200 to 800 ° C. with a maximum around 420 ° C. as the maximum.
- the peak observed around 100 to 200 ° C. with a maximum at around 150 ° C. in the desorption profile of water molecules is thought to be due to desorption of water physically adsorbed on the glass surface.
- a glass sample into which no hydrogen molecule has been introduced is similarly placed in a temperature-programmed desorption analyzer, the inside of the measurement chamber is evacuated to 5 ⁇ 10 ⁇ 7 Pa or less and heated, and the mass number of the generated gas Measure.
- a peak considered to be due to desorption of physically adsorbed water is observed in the vicinity of 100 to 200 ° C.
- no peak with a maximum around 420 ° C. was observed. Therefore, it can be considered that the peak observed around 200 ° C. to 800 ° C. with the maximum around 420 ° C. is due to the desorption of hydrogen molecules introduced into the glass.
- the number of desorbed hydrogen molecules of the measurement sample can be calculated from the integrated intensity ratio of the desorption peak of the hydrogen molecule between the measurement sample and a standard sample with a known hydrogen concentration.
- silicon ion-implanted silicon used as the standard sample
- the measurement method is as follows.
- 1 ⁇ 10 16 hydrogen ion-implanted silicon manufactured by Electronic Science Co., Ltd.
- 1 ⁇ 10 16 hydrogen ion-implanted silicon manufactured by Electronic Science Co., Ltd.
- was placed in a temperature programmed desorption analyzer was placed in a temperature programmed desorption analyzer and the inside of the measurement chamber was evacuated to 5 ⁇ 10 ⁇ 7 Pa or less and then heated.
- a desorption peak was observed around 350 to 750 ° C. with the maximum around 550 ° C. This peak is generated when 1 ⁇ 10 16 hydrogen ions in silicon are desorbed.
- the substrate 11 preferably has a smooth surface with a surface roughness (rms) of 0.15 nm or less and a flatness of 100 nm or less in order to obtain high reflectivity and transfer accuracy in a photomask after pattern formation. .
- the size, thickness, etc. of the substrate 11 are appropriately determined by the design value of the mask. In the examples described later, SiO 2 —TiO 2 glass having an outer shape of 6 inches (152 mm) square and a thickness of 0.25 inches (6.3 mm) was used. It is preferable that the surface of the substrate 11 on the side where the reflective layer 12 is formed has no defects.
- the depth of the concave defect and the height of the convex defect are not more than 2 nm so that the phase defect does not occur due to the concave defect and / or the convex defect. It is preferable that the half width of the defect and the convex defect is 60 nm or less.
- the reflective layer 12 is not particularly limited as long as it has desired characteristics as a reflective layer of an EUV mask blank.
- the characteristic particularly required for the reflective layer 12 is a high EUV light reflectance.
- the maximum value of light reflectance near a wavelength of 13.5 nm is preferably 60% or more, More preferably, it is 65% or more.
- the maximum value of the light reflectance near the wavelength of 13.5 nm is preferably 60% or more, and 65% or more. It is more preferable that
- the reflective layer 12 can achieve high EUV light reflectance, a multilayer reflective film in which a high refractive layer and a low refractive index layer are alternately laminated a plurality of times is usually used as the reflective layer 12.
- a multilayer reflective film in which a high refractive layer and a low refractive index layer are alternately laminated a plurality of times is usually used as the reflective layer 12.
- Mo is widely used for the high refractive index layer
- Si is widely used for the low refractive index layer. That is, the Mo / Si multilayer reflective film is the most common.
- the multilayer reflective film is not limited to this, and Ru / Si multilayer reflective film, Mo / Be multilayer reflective film, Mo compound / Si compound multilayer reflective film, Si / Mo / Ru multilayer reflective film, Si / Mo / Ru / A Mo multilayer reflective film and a Si / Ru / Mo / Ru multilayer reflective film can also be used.
- each layer constituting the multilayer reflective film constituting the reflective layer 12 and the number of repeating units of the layers can be appropriately selected according to the film material used and the EUV light reflectance required for the reflective layer.
- the multilayer reflective film is composed of a Mo layer having a film thickness of 2.3 ⁇ 0.1 nm, A Si layer having a thickness of 4.5 ⁇ 0.1 nm may be stacked so that the number of repeating units is 30 to 60.
- each layer which comprises the multilayer reflective film which comprises the reflective layer 12 so that it may become desired thickness using well-known film-forming methods, such as a magnetron sputtering method and an ion beam sputtering method.
- film-forming methods such as a magnetron sputtering method and an ion beam sputtering method.
- an Si / Mo multilayer reflective film is formed by ion beam sputtering
- an Si target is used as a target and Ar gas (gas pressure 1.3 ⁇ 10 ⁇ 2 Pa to 2.7 ⁇ 10 ⁇ as a sputtering gas). 2 Pa)
- an Si film is formed to have a thickness of 4.5 nm at an ion acceleration voltage of 300 to 1500 V and a film formation rate of 0.03 to 0.30 nm / sec.
- the Si / Mo multilayer reflective film is formed by laminating the Si film and the Mo film for 40 to 50 periods.
- the uppermost layer of the multilayer reflective film forming the reflective layer 12 is preferably a layer made of a material that is not easily oxidized.
- the layer of material that is not easily oxidized functions as a cap layer of the reflective layer 12.
- a Si layer can be exemplified.
- the uppermost layer can be made to function as a cap layer by making the uppermost layer an Si layer. In that case, the thickness of the cap layer is preferably 11 ⁇ 2 nm.
- the protective layer 13 is provided for the purpose of protecting the reflective layer 12 so that the reflective layer 12 is not damaged by the etching process when the absorber layer 14 is patterned by an etching process, usually a dry etching process. . Therefore, as the material of the protective layer 13, a material that is not easily affected by the etching process of the absorber layer 14, that is, the etching rate is slower than that of the absorber layer 14 and is not easily damaged by the etching process is selected. Examples of the material satisfying this condition include Cr, Al, Ta and nitrides thereof, Ru and Ru compounds (RuB, RuSi, etc.), and SiO 2 , Si 3 N 4 , Al 2 O 3 and mixtures thereof. Is done.
- the thickness of the protective layer 13 is preferably 1 to 60 nm.
- the protective layer 13 is formed using a known film formation method such as magnetron sputtering or ion beam sputtering.
- a Ru film is formed by magnetron sputtering
- a Ru target is used as a target
- Ar gas gas pressure: 1.0 ⁇ 10 ⁇ 2 Pa to 10 ⁇ 10 ⁇ 1 Pa
- the characteristic particularly required for the absorber layer 14 is that the EUV light reflectance is extremely low. Specifically, when the surface of the absorber layer 14 is irradiated with light in the wavelength region of EUV light, the maximum light reflectance near a wavelength of 13.5 nm is preferably 0.5% or less, 0.1% The following is more preferable. In the EUV mask blank 1 of the present invention, even when the surface of the low reflection layer 15 is irradiated with light in the wavelength region of EUV light, the maximum light reflectance near a wavelength of 13.5 nm may be 0.5% or less. Preferably, it is 0.1% or less.
- the absorber layer 14 is made of a material having a high EUV light absorption coefficient.
- a material having a high EUV light absorption coefficient a material mainly composed of tantalum (Ta) is preferably used.
- a material containing tantalum (Ta) as a main component means a material containing Ta in the material at 40 at% or more, preferably 50 at% or more, more preferably 55 at% or more.
- the material mainly composed of Ta used for the absorber layer 14 is not only Ta but also hafnium (Hf), silicon (Si), zirconium (Zr), germanium (Ge), boron (B), nitrogen (N) and hydrogen ( It may contain at least one element selected from H).
- the material containing the above elements other than Ta include, for example, TaN, TaNH, TaHf, TaHfN, TaBSi, TaBSiH, TaBSiN, TaBSiNH, TaB, TaBH, TaBN, TaBNH, TaSi, TaSiN, TaGe, TaGeN, TaZr, TaZrN, etc. are mentioned.
- the content of B is preferably 3 at% or less, more preferably 1 at% or less, and particularly preferably B is not included.
- the absorber layer 14 does not contain oxygen (O). Specifically, the O content in the absorber layer 14 is preferably less than 25 at%.
- O content in the absorber layer 14 is preferably less than 25 at%.
- a dry etching process is usually used.
- an etching gas a chlorine-based gas (or a mixed gas including a chlorine-based gas) or a fluorine gas (or a mixed gas including a fluorine-based gas) is used. Gas) is usually used.
- a film containing Ru or a Ru compound is formed as a protective layer on the reflective layer for the purpose of preventing the reflective layer from being damaged by the etching process, the protective layer is less damaged, so that it is mainly used as an etching gas.
- Chlorine-based gas is used. However, when the dry etching process is performed using a chlorine-based gas, if the absorber layer 14 contains oxygen, the etching rate is lowered, and resist damage is increased, which is not preferable.
- the oxygen content in the absorber layer 14 is preferably 15 at% or less, more preferably 10 at% or less, and even more preferably 5 at% or less.
- the thickness of the absorber layer 14 is preferably set so that the total thickness of the absorber layer 14 and the low reflective layer 15 is 30 to 200 nm, more preferably 35 to 200 nm, and even more preferably 50 to 200 nm. .
- the absorber layer 14 having the above-described configuration can be formed by performing a known film forming method, for example, a magnetron sputtering method or an ion beam sputtering method.
- a known film forming method for example, a magnetron sputtering method or an ion beam sputtering method.
- a TaNH film is formed as the absorber layer 14 using a magnetron sputtering method, it may be performed under the following conditions.
- Sputtering target Ta target Sputtering gas: Mixed gas of Ar, N 2 and H 2 (H 2 gas concentration 1 to 50 vol%, preferably 1 to 30 vol%, N 2 gas concentration 1 to 80 vol%, preferably 5 to 75 vol% , Ar gas concentration 5 to 95 vol%, preferably 10 to 94 vol%, gas pressure 1.0 ⁇ 10 ⁇ 1 Pa to 50 ⁇ 10 ⁇ 1 Pa, preferably 1.0 ⁇ 10 ⁇ 1 Pa to 40 ⁇ 10 ⁇ 1 Pa, more preferably 1.0 ⁇ 10 ⁇ 1 Pa to 30 ⁇ 10 ⁇ 1 Pa.)
- Input power 30 to 1000 W, preferably 50 to 750 W, more preferably 80 to 500 W
- Deposition rate 0.5 to 60 nm / min, preferably 1.0 to 45 nm / min, more preferably 1.5 to 30 nm / min
- the low reflection layer 15 is composed of a film exhibiting low reflection characteristics with respect to the wavelength of inspection light used for inspection of the mask pattern.
- an inspection machine using light of about 257 nm is currently used as inspection light. That is, the difference in reflectance with respect to the inspection light having such a wavelength, specifically, the surface where the absorber layer 14 is removed by pattern formation and the surface of the absorber layer 14 that remains without being removed by pattern formation. And the difference in reflectivity, that is, the contrast of reflected light on these surfaces.
- the former is the surface of the reflective layer 12.
- the protective layer 13 is formed on the reflective layer 12, it is the surface of the protective layer 13. Therefore, if the difference in reflectance between the surface of the reflective layer 12 or the protective layer 13 and the surface of the absorber layer 14 with respect to the wavelength of the inspection light is small, the contrast at the time of inspection deteriorates and accurate inspection cannot be performed. .
- the absorber layer 14 having the above-described configuration has extremely low EUV light reflectance, and has excellent characteristics as the absorber layer of the EUV mask blank 1, but when viewed with respect to the wavelength of inspection light, the light reflectance is low. It is not necessarily low enough. As a result, the difference between the reflectance on the surface of the absorber layer 14 and the reflectance on the surface of the protective layer 13 with respect to the wavelength of the inspection light becomes small, and there is a possibility that sufficient contrast at the time of inspection cannot be obtained. If sufficient contrast at the time of inspection is not obtained, pattern defects cannot be sufficiently determined in the inspection of the mask pattern, and accurate defect inspection cannot be performed.
- the low reflection layer 15 with respect to the inspection light of the mask pattern is formed on the absorber layer 14, whereby the contrast at the time of inspection becomes good.
- the contrast of the reflected light is the difference in reflectance between the surface of the reflective layer 12 and the surface of the low reflective layer 15 with respect to the wavelength of the inspection light.
- the protective layer 13 is formed on the reflective layer 12, this is the difference in reflectance between the surface of the protective layer 13 and the surface of the low reflective layer 15.
- the light reflectance is extremely low with respect to the wavelength range (190 to 260 nm) of the inspection light of the mask pattern.
- the light reflectance of the surface of the low reflection layer 15 is preferably 15% or less. It is more preferably 10% or less, and further preferably 8% or less. If the maximum light reflectance on the surface of the low reflective layer 15 is 15% or less with respect to the wavelength range (190 to 260 nm) of the inspection light of the mask pattern, the contrast at the time of inspection is good.
- the contrast between the reflected light) and the reflected light on the surface of the low reflection layer 15 is 60% or more.
- Contrast (%) ((R 2 ⁇ R 1 ) / (R 2 + R 1 )) ⁇ 100
- R 2 is the reflectance at the surface of the reflective layer 12 with respect to the wavelength of the inspection light.
- R 1 is the reflectance at the surface of the low reflection layer 15 with respect to the wavelength of the inspection light.
- the above R 1 and R 2 are, as shown in FIG. 2, is measured in a state of forming a pattern on the absorber layer 14 and the low reflective layer 15 of the EUV mask blank 1 shown in Figure 1.
- the R 2 is a value measured on the surface of the reflective layer 12 or the protective layer 13 exposed to the outside after the absorber layer 14 and the low reflective layer 15 are removed by pattern formation in FIG. 2, and R 1 is the pattern formation. This is a value measured on the surface of the low reflective layer 15 remaining without being removed by.
- the contrast represented by the above formula is more preferably 65% or more, and further preferably 70% or more.
- the low reflective layer 15 needs to satisfy a desired reflectance in a wavelength range (400 to 1200 nm) required in a mask manufacturing process and a pattern transfer process, and preferably satisfies the following requirements.
- the low reflective layer 15 of the EUV mask blank 1 of the present invention preferably contains the elements described below in a specific ratio.
- the first aspect of the low reflection layer 15 is a TaOH film containing at least tantalum (Ta), oxygen (O), and hydrogen (H).
- Ta tantalum
- O oxygen
- H hydrogen
- the composition (atomic) ratio of Ta and O is preferably 1: 8 to 3: 1.
- the H content is preferably 1 to 15 at%, more preferably 3 to 15 at%, 5 to 15 at%, 5 to 12 at%, and 5 to 10 at%.
- the total content of Ta and O is more preferably 85 to 99 at%, further preferably 85 to 95 at%, and particularly preferably 90 to 95 at%.
- the composition ratio of Ta and O is preferably 1: 7 to 2: 1, more preferably 1: 6 to 1: 1, and particularly preferably 1: 5 to 1: 1.
- the second aspect of the low reflective layer 15 is a TaONH film containing at least tantalum (Ta), oxygen (O), nitrogen (N), and hydrogen (H).
- Ta tantalum
- O oxygen
- N nitrogen
- H hydrogen
- the total content of Ta, O and N is 85 to 99.9 at%
- the content of H is 0.1 to 15 at%.
- H is a material having a low EUV light absorption coefficient, if the H content of the low reflective layer 15 exceeds 15 at%, it depends on the H content and film thickness of the absorber layer 14.
- the composition (atomic) ratio of Ta to (O + N) is preferably 1: 8 to 3: 1.
- the H content is more preferably 1 to 15 at%, further preferably 3 to 15 at%, and further preferably 5 to 15 at%. It is particularly preferred. Further, the total content of Ta, O and N is more preferably 85 to 99 at%, further preferably 85 to 95 at%, and particularly preferably 90 to 95 at%.
- the composition ratio of Ta and (O + N) is preferably 1: 7 to 2: 1, more preferably 1: 6 to 1: 1, 1: 5 to 1: 1, 1: 4 to Particularly preferred is 1: 2.
- the film may contain elements other than these elements.
- the TaONH film is a film containing at least Ta, O, N and H, the film may contain other elements other than these elements.
- the content of other elements is preferably 5 at% or less, preferably 2 at% or less, and preferably 1 at% or less. Is particularly preferred.
- the Cr content in the low reflection layer is preferably 3 at% or less, preferably 2 at% or less, and particularly preferably 1 at% or less.
- the content of Ti in the low reflection layer is preferably 3 at% or less, preferably 2 at% or less, and particularly preferably 1 at% or less.
- the content of B in the low reflection layer is preferably 5 at% or less, preferably 3 at% or less, particularly preferably 1 at% or less, and particularly preferably B is not contained.
- the hydrogen content in the low reflection layer is 1 at% or more, 2.5 at% or more, and 4 to 8 at% more than the hydrogen content in the absorber layer in terms of low reflection performance. preferable.
- the low reflective layer 15 (TaOH film, TaONH film) is preferably amorphous because of the above structure.
- the phrase “crystalline state is amorphous” includes a microcrystalline structure other than an amorphous structure having no crystal structure.
- the surface roughness (rms) of the surface of the low reflection layer 15 is preferably 0.5 nm or less.
- the surface roughness of the surface of the absorber layer 15 can be measured using an atomic force microscope (Atomic Force Microscope).
- the surface of the low reflection layer 15 is required to be smooth. If the surface roughness (rms) of the surface of the low reflection layer 15 is 0.5 nm or less, the surface of the low reflection layer 15 is sufficiently smooth, and there is no possibility that the dimensional accuracy of the pattern is deteriorated due to the influence of edge roughness.
- the surface roughness (rms) of the surface of the low reflective layer 15 is more preferably 0.4 nm or less, and further preferably 0.3 nm or less.
- the crystal state of the low reflective layer 15 (TaOH film, TaONH film) is amorphous, that is, an amorphous structure or a microcrystalline structure. Can do. If the crystal state of the low reflective layer 15 is an amorphous structure or a microcrystalline structure, a sharp peak is not observed in a diffraction peak obtained by XRD measurement.
- the low reflection layer may be formed by oxidizing the surface of the absorber layer by oxygen plasma treatment or the like.
- the total film thickness of the absorber layer 14 and the low reflection layer 15 is preferably 30 to 200 nm, more preferably 35 to 200 nm, and even more preferably 50 to 200 nm. .
- the thickness of the low reflective layer 15 is larger than the thickness of the absorber layer 14, the EUV light absorption characteristics in the absorber layer 14 may be deteriorated. It is preferably smaller than the film thickness of the layer. Therefore, the thickness of the low reflection layer 15 is preferably 3 to 30 nm, and more preferably 5 to 20 nm. Moreover, it is preferable that the low reflection layer 15 is in direct contact with the absorber layer in terms of low reflection performance.
- the low reflection layer 15 (TaOH film, TaONH film) having the above-described configuration can be formed by performing a sputtering method using a Ta target, for example, a magnetron sputtering method or an ion beam sputtering method.
- a sputtering method using a Ta target, for example, a magnetron sputtering method or an ion beam sputtering method.
- a Ta target for example, a magnetron sputtering method or an ion beam sputtering method.
- an inert gas containing at least one of helium (He), argon (Ar), neon (Ne), krypton (Kr), and xenon (Xe), and oxygen (O)
- a Ta target is discharged in an atmosphere containing hydrogen (H).
- an inert gas containing at least one of helium (He), argon (Ar), neon (Ne), krypton (Kr), and xenon (Xe), oxygen ( O), nitrogen (N), and hydrogen (H) are formed by discharging a Ta target in an atmosphere.
- the following film formation conditions may be used.
- Deposition conditions of low reflective layer 15 (TaOH film) Sputtering gas Ar, O 2 and H 2 mixed gas (H 2 gas concentration 1 to 50 vol%, preferably 1 to 30 vol%, O 2 gas concentration 1 to 80 vol%, Preferably 5 to 75 vol%, Ar gas concentration 5 to 95 vol%, preferably 10 to 94 vol%, gas pressure 1.0 ⁇ 10 ⁇ 1 Pa to 50 ⁇ 10 ⁇ 1 Pa, preferably 1.0 ⁇ 10 ⁇ 1 Pa To 40 ⁇ 10 ⁇ 1 Pa, more preferably 1.0 ⁇ 10 ⁇ 1 Pa to 30 ⁇ 10 ⁇ 1 Pa.)
- Input power 30 to 1000 W, preferably 50 to 750 W, more preferably 80 to 500 W
- Deposition rate 0.01 to 60 nm / min, preferably 0.05 to 45 nm / min, more preferably 0.1 to 30 nm / min
- Deposition conditions of the low reflection layer 15 (TaONH film) Sputtering gas Ar, O 2 , N 2 and H 2 mixed gas (H 2 gas concentration 1 to 50 vol%, preferably 1 to 30 vol%, O 2 gas concentration 1 ⁇ 80 vol%, preferably 5 ⁇ 75vol%, N 2 gas concentration 1 ⁇ 80 vol%, preferably 5 ⁇ 75vol%, Ar gas concentration 5 ⁇ 95 vol%, preferably 10 ⁇ 89vol%, gas pressure 1.0 ⁇ 10 - 1 Pa to 50 ⁇ 10 ⁇ 1 Pa, preferably 1.0 ⁇ 10 ⁇ 1 Pa to 40 ⁇ 10 ⁇ 1 Pa, more preferably 1.0 ⁇ 10 ⁇ 1 Pa to 30 ⁇ 10 ⁇ 1 Pa.)
- Input power 30 to 1000 W, preferably 50 to 750 W, more preferably 80 to 500 W
- Deposition rate 0.01 to 60 nm / min, preferably 0.05 to 45 nm / min, more preferably 0.1 to 30 nm / min
- an inert gas other than Ar
- the EUV mask blank 1 of the present invention may have a functional film known in the field of EUV mask blanks in addition to the reflective layer 12, the protective layer 13, the absorber layer 14, and the low reflective layer 15.
- a functional film for example, as described in Japanese Patent Application Publication No. 2003-501823, a high dielectric material applied to the back side of the substrate in order to promote electrostatic chucking of the substrate.
- a functional coating here, the back surface of the substrate refers to the surface of the substrate 11 in FIG. 1 opposite to the side on which the reflective layer 12 is formed.
- the electrical conductivity and thickness of the constituent material are selected so that the sheet resistance is 100 ⁇ / ⁇ or less.
- the constituent material of the high dielectric coating can be widely selected from those described in known literature.
- a high dielectric constant coating described in JP-A-2003-501823 specifically, a coating made of silicon, TiN, molybdenum, chromium, or TaSi can be applied.
- the thickness of the high dielectric coating can be, for example, 10 to 1000 nm.
- the high dielectric coating can be formed using a known film formation method, for example, a sputtering method such as a magnetron sputtering method or an ion beam sputtering method, a CVD method, a vacuum evaporation method, or an electrolytic plating method.
- the patterning method of the absorber layer is not particularly limited, and for example, a method of applying a resist on the absorber layer to form a resist pattern and etching the absorber layer using this as a mask can be employed.
- the resist material and the resist pattern drawing method may be appropriately selected in consideration of the material of the absorber layer and the like.
- the method for etching the absorber layer is not particularly limited, and dry etching such as reactive ion etching or wet etching can be employed.
- the EUV mask is obtained by stripping the resist with a stripping solution.
- the present invention can be applied to a method for manufacturing a semiconductor integrated circuit by a photolithography method using EUV light as an exposure light source.
- a substrate such as a silicon wafer coated with a resist is placed on a stage, and the EUV mask is installed in a reflective exposure apparatus configured by combining a reflecting mirror.
- the EUV light is irradiated from the light source to the EUV mask through the reflecting mirror, and the EUV light is reflected by the EUV mask and irradiated to the substrate coated with the resist.
- the circuit pattern is transferred onto the substrate.
- the substrate on which the circuit pattern has been transferred is subjected to development to etch the photosensitive portion or the non-photosensitive portion, and then the resist is removed.
- a semiconductor integrated circuit is manufactured by repeating such steps.
- Example 1 the EUV mask blank 1 shown in FIG. 1 was produced.
- a SiO 2 —TiO 2 glass substrate (outer diameter 6 inches (152 mm) square, thickness 6.3 mm) was used.
- This glass substrate has a thermal expansion coefficient of 0.2 ⁇ 10 ⁇ 7 / ° C., a Young's modulus of 67 GPa, a Poisson's ratio of 0.17, and a specific rigidity of 3.07 ⁇ 10 7 m 2 / s 2 .
- This glass substrate was polished to form a smooth surface with a surface roughness (rms) of 0.15 nm or less and a flatness of 100 nm or less.
- a high dielectric coating having a sheet resistance of 100 ⁇ / ⁇ was applied to the back side of the substrate 11 by depositing a Cr film having a thickness of 100 nm using a magnetron sputtering method.
- a substrate 11 (outer diameter 6 inches (152 mm) square, thickness 6.3 mm) is fixed to a flat electrostatic chuck having a flat plate shape by using the formed Cr film, and ion beam sputtering is performed on the surface of the substrate 11.
- the Si / Mo multilayer reflective film (reflective layer 12) having a total film thickness of 272 nm ((4.5 nm + 2.3 nm) ⁇ 40) is obtained by repeating 40 cycles of alternately forming the Si film and the Mo film using the method. Formed.
- a protective layer 13 was formed by forming a Ru film (film thickness: 2.5 nm) on the Si / Mo multilayer reflective film (reflective layer 12) using an ion beam sputtering method.
- the deposition conditions for the Si film, the Mo film, and the Ru film are as follows. Conditions for forming the Si film Target: Si target (boron doped) Sputtering gas: Ar gas (gas pressure 0.02 Pa) Voltage: 700V Deposition rate: 0.077 nm / sec Film thickness: 4.5nm Conditions for forming the Mo film Target: Mo target Sputtering gas: Ar gas (gas pressure 0.02 Pa) Voltage: 700V Deposition rate: 0.064 nm / sec Film thickness: 2.3 nm Ru film formation conditions Target: Ru target sputtering gas: Ar gas (gas pressure 0.02 Pa) Voltage: 500V Deposition rate: 0.023 nm / sec Film thickness: 2.5nm
- the absorber layer 14 (TaNH film) was formed by the following method.
- the film composition includes an X-ray photoelectron spectrometer (manufactured by PERKIN ELEMER-PHI), a secondary ion mass spectrometer (secondary ion mass spectrometer) (manufactured by PHI-ATOMIKA), and Rutherford backscattering spectrometer (manufactured by Rutherford). Measurement is performed using Ruferford Back Scattering Spectroscopy (manufactured by Kobe Steel).
- the O content in the absorber layer is 0.05 at% or less.
- Film formation conditions for absorber layer 14 (TaNH film)
- Target Ta target Sputter gas: Mixed gas of Ar, N 2 and H 2 (Ar: 89 vol%, N 2 : 8.3 vol%, H 2 : (2.7 vol%, gas pressure: 0.46 Pa)
- Input power 300W Deposition rate: 1.5 nm / min Film thickness: 70nm
- a low reflection layer 15 (TaONH film) containing Ta, O, N, and H is formed on the absorber layer 14 by using a magnetron sputtering method, whereby the reflection layer 12 and the protective layer are formed on the substrate 11.
- the film forming conditions of the low reflective layer 15 (TaONH film) are as follows.
- Ta target Sputtering gas mixed gas of Ar and O 2 N 2 and H 2 (Ar: 48vol%, O 2: 36vol%, N 2 : 14 vol%, H 2 : 2 vol%, gas pressure: 0.3 Pa)
- Input power 450W Deposition rate: 1.5 nm / min Film thickness: 10nm
- the following evaluations (1) to (5) were performed on the low reflective layer 15 (TaONH film) of the EUV mask blank obtained by the above procedure.
- (1) Film composition The composition of the low-reflection layer 15 (TaONH film) is determined using an X-ray photoelectron spectrometer (manufactured by PERKIN ELEMER-PHI), Rutherford backscattering spectrometer (Rutherford Back Scattering Spectroscopy). Measured using Kobe Steel).
- the surface roughness of the low reflective layer 15 is measured by a dynamic force mode using an atomic force microscope (SII, SPI-3800).
- the surface roughness measurement area is 1 ⁇ m ⁇ 1 ⁇ m, and SI-DF40 (manufactured by SII) is used as the cantilever.
- the surface roughness (rms) of the low reflection layer is 0.30 nm.
- the contrast at a wavelength of 257 nm was 79.9%.
- the contrast between the surface of the protective layer 13 and the surface of the low reflection layer 15 was 70% or more with respect to the wavelength of the inspection light of the mask pattern, and a sufficient contrast was obtained.
- the EUV light (wavelength 13.5nm) is irradiated to the surface of the low reflection layer 15 (TaONH film
- Example 2 In this example, the same procedure as in Example 1 was performed except that the low reflective layer 15 was TaOH, and the reflective layer 12, the protective layer 13, the absorber layer 14 (TaNH), and the low reflective layer were formed on the substrate 11.
- An EUV mask blank 1 in which 15 (TaOH) is formed in this order is obtained.
- the film forming conditions for the low reflective layer 15 (TaOH) are as follows.
- the surface roughness (rms) of the low reflective layer 15 (TaOH film) was examined by the same procedure as in Example 1, it was 0.31 nm.
- the reflection characteristics of the EUV blanks obtained by the above procedure are evaluated in the same manner as in Example 1.
- the reflectance with respect to the wavelength of 257 nm on the surface of the low reflective layer 15 (TaOH film) was evaluated in the same manner as in Example 1, it was 5.9% and was 15% or less. From these results, the contrast at a wavelength of 257 nm is 80.9%.
- the contrast between the surface of the protective layer 13 and the surface of the low reflection layer 15 is 70% or more with respect to the wavelength of the inspection light of the mask pattern, and a sufficient contrast can be obtained.
- the EUV light (wavelength 13.5nm) is irradiated to the surface of the low reflection layer 15 (TaOH film), and the reflectance of EUV light is measured. As a result, the reflectance of EUV light is 0.5%.
- the reflectance with respect to the wavelength of 400 to 1200 nm on the surface of the low reflective layer 15 (TaOH film) is evaluated in the same manner as in Example 1.
- the reflectance for a predetermined wavelength is as follows.
- Example 3 In this example, the same procedure as in Example 1 is performed except that the absorber layer 14 is a TaN film.
- the O content in the absorber layer is 0.05 at% or less.
- the film forming conditions of the absorber layer 14 (TaN) are as follows.
- Ta target Sputtering gas mixed gas of Ar and N 2 (Ar: 86vol%, N 2: 14vol%, gas pressure: 0.37 Pa)
- Input power 300W
- Deposition rate 1.1 nm / min
- Film thickness 60nm
- a low reflective layer 15 is formed on the absorber layer 14 in the same procedure as in Example 1, and the reflective layer 12, the protective layer 13, the absorber layer 14 (TaN), low on the substrate 11 is formed.
- the EUV mask blank 1 in which the reflective layer 15 (TaONH) is formed in this order is obtained.
- the reflection characteristics of the EUV blanks obtained by the above procedure are evaluated in the same manner as in Example 1.
- the reflectance with respect to the wavelength of 257 nm on the surface of the low reflective layer 15 was evaluated in the same manner as in Example 1, it was 6.0% and 15% or less. From these results, the contrast at a wavelength of 257 nm is 80.6%.
- the contrast between the surface of the protective layer 13 and the surface of the low reflection layer 15 is 70% or more with respect to the wavelength of the inspection light of the mask pattern, and a sufficient contrast can be obtained.
- the EUV light (wavelength 13.5nm) is irradiated to the surface of the low reflection layer 15 (TaONH film
- the reflectance with respect to the wavelength of 400 to 1200 nm on the surface of the low reflective layer 15 is evaluated in the same manner as in Example 1.
- the reflectance for a predetermined wavelength is as follows. [Target value] ⁇ 405 nm: ⁇ 40% ⁇ 600 to 650 nm: 30 to 50% ⁇ 800-900nm:> 50% ⁇ 1000-1200nm: ⁇ 90% [Measurement result] ⁇ 405 nm: 30% ⁇ 600 to 650 nm: 43 to 46% ⁇ 800-900nm: 51-56% ⁇ 1000-1200nm: ⁇ 65%
- the reflectance is within the range of the target value for any wavelength.
- Example 4 In this example, the same procedure as in Example 2 is performed except that the absorber layer 14 is a TaN film.
- the absorber layer 14 (TaN film) is manufactured in the same procedure as in Example 3, and the reflective layer 12, the protective layer 13, the absorber layer 14 (TaN), and the low reflective layer 15 (TaOH) are formed on the substrate 11 in this manner.
- the EUV mask blank 1 formed in this order is obtained.
- the reflection characteristics of the EUV blanks obtained by the above procedure are evaluated in the same manner as in Example 1. When the reflectance with respect to the wavelength of 257 nm on the surface of the low reflective layer 15 (TaOH film) was evaluated in the same manner as in Example 1, it was 6.1% and 15% or less.
- the contrast at a wavelength of 257 nm is 80.3%.
- the contrast between the surface of the protective layer 13 and the surface of the low reflection layer 15 is 70% or more with respect to the wavelength of the inspection light of the mask pattern, and a sufficient contrast can be obtained.
- the EUV light (wavelength 13.5nm) is irradiated to the surface of the low reflection layer 15 (TaOH film), and the reflectance of EUV light is measured. As a result, the reflectance of EUV light is 0.4%.
- the reflectance with respect to the wavelength of 400 to 1200 nm on the surface of the low reflective layer 15 (TaOH film) is evaluated in the same manner as in Example 1.
- the reflectance for a predetermined wavelength is as follows.
- Example 5 In this example, the same procedure as in Example 1 is performed except that the absorber layer 14 is a TaBN film.
- the O content in the absorber layer is 0.05 at% or less.
- the film forming conditions of the absorber layer 14 (TaBN) are as follows.
- TaBN layer target TaB compound target (composition ratio: Ta 80 at%, B 20 at%)
- Sputtering gas Ar and N 2 mixed gas (Ar: 80 vol%, N 2 : 20 vol%, gas pressure: 0.46 Pa)
- Input power 300W
- Deposition rate 1.2 nm / min
- Film thickness 60nm
- a low reflective layer 15 is formed on the absorber layer 14 in the same procedure as in Example 1, and the reflective layer 12, the protective layer 13, the absorber layer 14 (TaBN), low on the substrate 11 is formed.
- the EUV mask blank 1 in which the reflective layer 15 (TaONH) is formed in this order is obtained.
- the reflection characteristics of the EUV blanks obtained by the above procedure are evaluated in the same manner as in Example 1.
- the contrast between the surface of the protective layer 13 and the surface of the low reflection layer 15 is 70% or more with respect to the wavelength of the inspection light of the mask pattern, and a sufficient contrast can be obtained.
- the EUV light (wavelength 13.5nm) is irradiated to the surface of the low reflection layer 15 (TaONH film
- the reflectance with respect to the wavelength of 400 to 1200 nm on the surface of the low reflective layer 15 (TaONH film) is evaluated in the same manner as in Example 1.
- the reflectance for a predetermined wavelength is as follows.
- Example 6 In this example, the same procedure as in Example 1 is performed except that the absorber layer 14 is a TaBNH film.
- the O content in the absorber layer is 0.05 at% or less.
- the film formation conditions of the absorber layer 14 (TaBNH) are as follows.
- TaB compound target Composition ratio: Ta 80 at%, B 20 at%)
- Sputtering gas Mixed gas of Ar, N 2 and H 2 (Ar: 80 vol%, N 2 : 17.3 vol%, H 2 : 2.7 vol%, gas pressure: 0.46 Pa)
- Input power 300W
- Deposition rate 1.5 nm / min
- Film thickness 60nm
- a low reflective layer 15 is formed on the absorber layer 14 in the same procedure as in Example 1, and the reflective layer 12, the protective layer 13, the absorber layer 14 (TaBNH), low on the substrate 11 is formed.
- the EUV mask blank 1 in which the reflective layer 15 (TaONH) is formed in this order is obtained.
- the reflection characteristics of the EUV blanks obtained by the above procedure are evaluated in the same manner as in Example 1.
- the reflectance with respect to the wavelength of 257 nm on the surface of the low reflective layer 15 (TaONH film) was evaluated in the same manner as in Example 1, it was 6.2% and was 15% or less. From these results, the contrast at a wavelength of 257 nm is 80.0%.
- the contrast between the surface of the protective layer 13 and the surface of the low reflection layer 15 is 70% or more with respect to the wavelength of the inspection light of the mask pattern, and a sufficient contrast can be obtained.
- the EUV light (wavelength 13.5nm) is irradiated to the surface of the low reflection layer 15 (TaONH film
- the reflectance with respect to the wavelength of 400 to 1200 nm on the surface of the low reflective layer 15 (TaONH film) is evaluated in the same manner as in Example 1.
- the reflectance for a predetermined wavelength is as follows.
- Comparative Example 1 In this comparison, the same procedure as in Example 1 was performed except that the low reflective layer 15 was not a hydrogen (H) but a TaON film containing tantalum (Ta), oxygen (O), and nitrogen (N). .
- the film forming conditions of the low reflective layer 15 (TaON film) are as follows.
- the reflection characteristics of the low reflective layer 15 (TaON film) of the EUV mask blank obtained by the above procedure were evaluated in the same manner as in Example 1.
- the reflectance with respect to the wavelength of 257 nm on the surface of the low reflective layer 15 (TaON film) was 9.0%, which was 15% or less.
- the contrast at a wavelength of 257 nm was 72.3%.
- the contrast between the surface of the protective layer 13 and the surface of the low reflection layer 15 was 70% or more with respect to the wavelength of the inspection light of the mask pattern, and a sufficient contrast was obtained.
- the reflectivity with respect to the wavelength of 400 to 1200 nm on the surface of the low reflective layer 15 (TaON film) was as follows.
- the mask blank of the present invention can be used for manufacturing a semiconductor integrated circuit by a photolithography method using EUV light as an exposure light source. It should be noted that the entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2008-279899 filed on Oct. 30, 2008 are cited here as disclosure of the specification of the present invention. Incorporated.
- EUV mask blank 11 Substrate 12: Reflective layer (multilayer reflective film) 13: Protective layer 14: Absorber layer 15: Low reflective layer
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Abstract
Description
また、特許文献2には、マスクパターンの検査光の波長域(190nm~260nm)に対する反射率を調整するために、吸収体層上に金属、珪素(Si)、酸素(O)および窒素(N)からなる低反射層を設けることが好ましいとされている。
しかしながら、マスク作製プロセスおよびパターン転写プロセスにおいて、マスクパターン検査波長(190~260nm)の反射率だけでなく、400~1200nmの波長に対する反射率も重要である。400~1200nmの波長を有する光は、マスクの搬送時やハンドリング時の「位置センサー」として通常用いられており、所望の反射率範囲にない場合、基板位置精度の悪化すなわちパターン精度の悪化という問題が生じる可能性がある。位置センサーとして使用される光の波長に対する反射率は、各プロセス(検査、パターン描画、エッチング、露光)で用いられる装置によって異なるが、一般的には、「405nmで40%未満」、「600~650nmで30~50%」、「800~900nmで50%超」、「1000~1200nmで90%未満」が求められることが多い。
前記低反射層が、タンタル(Ta)、酸素(O)および水素(H)を少なくとも含有し、
前記低反射層(TaOH膜)において、TaおよびOの合計含有率が85~99.9at%(原子百分率、以下同じ)であり、Hの含有率が0.1~15at%であることを特徴とするEUVリソグラフィ用反射型マスクブランク(以下、「本発明のEUVマスクブランク」という。)を提供する。
なお、本発明において、組成比とは、原子比を意味する。
前記低反射層が、タンタル(Ta)、酸素(O)、窒素(N)および水素(H)を少なくとも含有し、
前記低反射層(TaONH膜)において、Ta、OおよびNの合計含有率が85~99.9at%であり、Hの含有率が0.1~15at%であることを特徴とするEUVリソグラフィ用反射型マスクブランクを提供する。
本発明のEUVマスクブランクにおいて、前記低反射層(TaOH膜およびTaONH膜)の結晶構造が、アモルファスであることが好ましい。
本発明のEUVマスクブランクにおいて、前記低反射層(TaOH膜およびTaONH膜)の膜厚が、3~30nmであることが好ましい。
本発明のEUVマスクブランクにおいて、前記吸収体層が、タンタル(Ta)を主成分とし、ハフニウム(Hf)、珪素(Si)、ジルコニウム(Zr)、ゲルマニウム(Ge)、硼素(B)、窒素(N)および水素(H)から選ばれる少なくとも1種類の元素を含んでも良い。
本発明のEUVマスクブランクにおいて、前記吸収体層は、酸素(O)の含有率が25at%未満であることが好ましい。
本発明のEUVマスクブランクにおいて、前記吸収体層および前記低反射層の膜厚が、30~200nmであることが好ましい。
前記マスクパターンの検査光の波長(190~260nm)に対する前記保護層表面での反射光と、前記低反射層(TaOH膜およびTaONH膜)表面での反射光と、のコントラストが、60%以上であることが好ましい。
本発明のEUVマスクブランクにおいて、前記低反射層中の水素の含有量は、前記吸収体層中の水素の含有量よりも、1at%以上多いことが好ましい。
前記低反射層が、ヘリウム(He)、アルゴン(Ar)、ネオン(Ne)、クリプトン(Kr)、キセノン(Xe)のうち少なくともひとつを含む不活性ガスと、酸素(O)および水素(H)を含む雰囲気中でTaターゲットを用いたスパッタリング法を行うことにより形成されることを特徴とするEUVリソグラフィ用反射型マスクブランクの製造方法を提供する。
前記低反射層が、ヘリウム(He)、アルゴン(Ar)、ネオン(Ne)、クリプトン(Kr)、キセノン(Xe)のうち少なくともひとつを含む不活性ガスと、酸素(O)、窒素(N)および水素(H)を含む雰囲気中でTaターゲットを用いたスパッタリング法を行うことにより形成されることを特徴とするEUVリソグラフィ用反射型マスクブランクの製造方法を提供する。
図1は、本発明のEUVマスクブランクの1実施形態を示す概略断面図である。図1に示すマスクブランク1は、基板11上にEUV光を反射する反射層12と、EUV光を吸収する吸収体層14とがこの順に形成されている。反射層12と吸収体層14との間には、吸収体層14へのパターン形成時に反射層12を保護するための保護層13が形成されている。吸収体層14上には、マスクパターンの検査光に対する低反射層15が形成されている。但し、本発明のEUVマスクブランク1において、図1に示す構成中、基板11、反射層12、吸収体層14および低反射層15のみが必須であり、保護層13は任意の構成要素である。
以下、マスクブランク1の個々の構成要素について説明する。
そのため、基板11は、低熱膨張係数(具体的には、20℃における熱膨張係数が0±0.05×10-7/℃であることが好ましく、特に好ましくは0±0.03×10-7/℃)を有し、平滑性、平坦度、およびマスクブランクまたはパターン形成後のフォトマスクの洗浄等に用いる洗浄液への耐性に優れたものが好ましい。基板11としては、具体的には低熱膨張係数を有するガラス、例えばSiO2-TiO2系ガラス等を用いるが、これに限定されず、β石英固溶体を析出した結晶化ガラスや石英ガラスやシリコンや金属などの基板を用いることもできる。
水素分子を導入したガラス試料を昇温脱離分析装置内に入れ、その測定室内部を5×10-7Pa以下まで真空引きした後ガラス試料を加熱し、発生したガスの質量数を分析装置内部に設置された質量分析計にて測定する。水素分子の脱離プロファイルにおいて、420℃付近を最大とし200~800℃付近にピークが観測される。また水分子の脱離プロファイルにおいて150℃付近を最大とし100~200℃付近に観測されたピークは、ガラス表面に物理吸着した水が脱離したものによると考えられる。
よって、420℃付近を最大とし200~800℃付近に観測されたピークは、ガラス中に導入した水素分子が脱離したことによるものと考えることができる。したがって、測定サンプルと水素濃度が既知の標準サンプルとの上記水素分子の脱離ピークの積分強度比より、測定サンプルの脱離した水素分子数を算出することができる。
例えば、標準サンプルとして水素イオン注入したシリコンを用いた場合、以下のような測定方法となる。1×1016個の水素イオン注入したシリコン(電子科学社製)を、同様に、昇温脱離分析装置内に入れ測定室内部を5×10-7Pa以下まで真空引きした後加熱した。550℃付近を最大とし350~750℃付近に脱離ピークが観測された。このピークはシリコン中の1×1016個の水素イオンが脱離した際に発生したものである。
基板11の大きさや厚みなどはマスクの設計値等により適宜決定されるものである。後で示す実施例では外形6インチ(152mm)角で、厚さ0.25インチ(6.3mm)のSiO2-TiO2系ガラスを用いた。
基板11の反射層12が形成される側の表面には欠点が存在しないことが好ましい。しかし、存在している場合であっても、凹状欠点および/または凸状欠点によって位相欠点が生じないように、凹状欠点の深さおよび凸状欠点の高さが2nm以下であり、かつこれら凹状欠点および凸状欠点の半値幅が60nm以下であることが好ましい。
保護層13の厚さは1~60nmであることが好ましい。
本発明のEUVマスクブランク1においては、EUV光の波長領域の光線を低反射層15表面に照射した際にも、波長13.5nm付近の最大光線反射率が0.5%以下であることが好ましく、0.1%以下であることがより好ましい。
吸収体層14に用いるTaを主成分とする材料は、Ta以外にハフニウム(Hf)、珪素(Si)、ジルコニウム(Zr)、ゲルマニウム(Ge)、硼素(B)、窒素(N)および水素(H)から選ばれる少なくとも1種類の元素を含んでも良い。Ta以外の上記の元素を含有する材料の具体例としては、例えば、TaN、TaNH、TaHf、TaHfN、TaBSi、TaBSiH、TaBSiN、TaBSiNH、TaB、TaBH、TaBN、TaBNH、TaSi、TaSiN、TaGe、TaGeN、TaZr、TaZrNなどが挙げられる。
ただし、吸収体層において、Bの含有量は3at%以下が好ましく、1at%以下がより好ましく、特にBを含まないことが好ましい。
例えば、吸収体層14として、マグネトロンスパッタリング法を用いてTaNH膜を形成する場合、以下の条件で実施すればよい。
スパッタリングターゲット:Taターゲット
スパッタガス:ArとN2とH2の混合ガス(H2ガス濃度1~50vol%、好ましくは1~30vol%、N2ガス濃度1~80vol%、好ましくは5~75vol%、Arガス濃度5~95vol%、好ましくは10~94vol%、ガス圧1.0×10-1Pa~50×10-1Pa、好ましくは1.0×10-1Pa~40×10-1Pa、より好ましくは1.0×10-1Pa~30×10-1Pa。)
投入電力:30~1000W、好ましくは50~750W、より好ましくは80~500W
成膜速度:0.5~60nm/min、好ましくは1.0~45nm/min、より好ましくは1.5~30nm/min
マスクパターンの検査光の波長域(190~260nm)に対して低反射層15表面の最大光線反射率が15%以下であれば、検査時のコントラストが良好である。具体的には、マスクパターンの検査光の波長域(190~260nm)に対して、反射層12表面における反射光(反射層12上に保護層13が形成されている場合は保護層13表面における反射光)と、低反射層15表面における反射光と、のコントラストが60%以上となる。
コントラスト(%)=((R2-R1)/(R2+R1))×100
ここで、R2は検査光の波長に対する反射層12表面での反射率である。但し、反射層12上に保護層13が形成されている場合は保護層13表面での反射率である。R1は検査光の波長に対する低反射層15表面での反射率である。なお、上記R1およびR2は、図2に示すように、図1に示すEUVマスクブランク1の吸収体層14および低反射層15にパターンを形成した状態で測定する。上記R2は、図2中、パターン形成によって吸収体層14および低反射層15が除去され、外部に露出した反射層12表面または保護層13表面で測定した値であり、R1はパターン形成によって除去されずに残った低反射層15表面で測定した値である。
本発明において、上記式で表されるコントラストが65%以上であることがより好ましく、70%以上であることがさらに好ましい。
・405nm :<40%
・600~650nm :30~50%
・800~900nm :>50%
・1000~1200nm :<90%
上記の特性を達成するため、本発明のEUVマスクブランク1の低反射層15では、以下に述べる元素を特定の比率で含有することが好ましい。
Hの含有率が、0.1at%未満であると、マスク製造プロセスおよびパターン転写プロセスで必要とされる波長域(400~1200nm)で所望の反射率を満たすことができない。また、HはEUV光の吸収係数が低い材料であるため、低反射層15のHの含有率が15at%超であると、吸収体層14のHの含有率や膜厚にもよるが、EUV光線反射率を0.5%以下とするのに必要な吸収体層14および低反射層15の膜厚の合計が大きくなってしまうため好ましくない。
なお、低反射層15がTaOH膜である場合、TaとOの組成(原子)比が1:8~3:1であることが好ましい。
また、TaとOの合計含有率は、85~99at%であることがより好ましく、85~95at%であることがさらに好ましく、90~95at%であることが特に好ましい。
またTaとOの組成比は、1:7~2:1であることが好ましく、1:6~1:1であることがさらに好ましく、1:5~1:1であることが特に好ましい。
なお、低反射層15がTaONH膜である場合、Taと(O+N)の組成(原子)比が1:8~3:1であることが好ましい。
低反射性能の点で、低反射層中のCrの含有量は3at%以下、2at%以下であることが好ましく、1at%以下であることが特に好ましい。また、低反射層中のTiの含有量は3at%以下、2at%以下であることが好ましく、1at%以下であることが特に好ましい。低反射層中のBの含有量は、5at%以下、3at%以下であることが好ましく、1at%以下、さらにBを含まないことが特に好ましい。また、低反射層中の水素の含有量は、吸収体層中の水素の含有量よりも、1at%以上、2.5at%以上、さらには4~8at%多いことが低反射性能の点で好ましい。
低反射層15(TaOH膜、TaONH膜)がアモルファス構造の膜または微結晶構造の膜であることにより、低反射層15表面の表面粗さ(rms)が0.5nm以下であることが好ましい。ここで、吸収体層15表面の表面粗さは原子間力顕微鏡(Atomic Force Microscope)を用いて測定することができる。低反射層15表面の表面粗さが大きいと、低反射層15に形成されるパターンのエッジラフネスが大きくなり、パターンの寸法精度が悪くなる。パターンが微細になるに従いエッジラフネスの影響が顕著になるため、低反射層15表面は平滑であることが要求される。
低反射層15表面の表面粗さ(rms)が0.5nm以下であれば、低反射層15表面が十分平滑であるため、エッジラフネスの影響によってパターンの寸法精度が悪化するおそれがない。低反射層15表面の表面粗さ(rms)は0.4nm以下であることがより好ましく、0.3nm以下であることがさらに好ましい。
また、低反射層は、吸収体層の表面を、酸素プラズマ処理などにより酸化して作成してもよい。
また、低反射層15の膜厚が吸収体層14の膜厚よりも大きいと、吸収体層14でのEUV光吸収特性が低下するおそれがあるので、低反射層15の膜厚は吸収体層の膜厚よりも小さいことが好ましい。このため、低反射層15の厚さは3~30nmであることが好ましく、5~20nmであることがより好ましい。
また、低反射層15は、吸収体層と直接接していることが低反射性能の点で好ましい。
低反射層15がTaOH膜である場合、ヘリウム(He)、アルゴン(Ar)、ネオン(Ne)、クリプトン(Kr)、キセノン(Xe)のうち少なくともひとつを含む不活性ガスと、酸素(O)および水素(H)を含む雰囲気中でTaターゲットを放電させることによって形成する。
一方、低反射層15がTaONH膜である場合、ヘリウム(He)、アルゴン(Ar)、ネオン(Ne)、クリプトン(Kr)、キセノン(Xe)のうち少なくともひとつを含む不活性ガスと、酸素(O)、窒素(N)および水素(H)を含む雰囲気中でTaターゲットを放電させることによって形成する。
低反射層15(TaOH膜)の成膜条件
スパッタガス:ArとO2とH2混合ガス(H2ガス濃度1~50vol%、好ましくは1~30vol%、O2ガス濃度1~80vol%、好ましくは5~75vol%、Arガス濃度5~95vol%、好ましくは10~94vol%、ガス圧1.0×10-1Pa~50×10-1Pa、好ましくは1.0×10-1Pa~40×10-1Pa、より好ましくは1.0×10-1Pa~30×10-1Pa。)
投入電力:30~1000W、好ましくは50~750W、より好ましくは80~500W
成膜速度:0.01~60nm/min、好ましくは0.05~45nm/min、より好ましくは0.1~30nm/min
なお、Ar以外の不活性ガスを使用する場合、その不活性ガスの濃度が上記したArガス濃度と同じ濃度範囲にする。
低反射層15(TaONH膜)の成膜条件
スパッタガス:ArとO2とN2とH2の混合ガス(H2ガス濃度1~50vol%、好ましくは1~30vol%、O2ガス濃度1~80vol%、好ましくは5~75vol%、N2ガス濃度1~80vol%、好ましくは5~75vol%、Arガス濃度5~95vol%、好ましくは10~89vol%、ガス圧1.0×10-1Pa~50×10-1Pa、好ましくは1.0×10-1Pa~40×10-1Pa、より好ましくは1.0×10-1Pa~30×10-1Pa。)
投入電力:30~1000W、好ましくは50~750W、より好ましくは80~500W
成膜速度:0.01~60nm/min、好ましくは0.05~45nm/min、より好ましくは0.1~30nm/min
なお、Ar以外の不活性ガスを使用する場合、その不活性ガスの濃度が上記したArガス濃度と同じ濃度範囲にする。
高誘電性コーティングは、公知の成膜方法、例えば、マグネトロンスパッタリング法、イオンビームスパッタリング法といったスパッタリング法、CVD法、真空蒸着法、又は電解メッキ法を用いて形成することができる。
実施例1
本実施例では、図1に示すEUVマスクブランク1を作製した。
成膜用の基板11として、SiO2-TiO2系のガラス基板(外形6インチ(152mm)角、厚さが6.3mm)を使用した。このガラス基板の熱膨張率は0.2×10-7/℃、ヤング率は67GPa、ポアソン比は0.17、比剛性は3.07×107m2/s2である。このガラス基板を研磨により、表面粗さ(rms)が0.15nm以下の平滑な表面と100nm以下の平坦度に形成した。
平板形状をした通常の静電チャックに、形成したCr膜を用いて基板11(外形6インチ(152mm)角、厚さ6.3mm)を固定して、該基板11の表面上にイオンビームスパッタリング法を用いてSi膜およびMo膜を交互に成膜することを40周期繰り返すことにより、合計膜厚272nm((4.5nm+2.3nm)×40)のSi/Mo多層反射膜(反射層12)を形成した。
さらに、Si/Mo多層反射膜(反射層12)上に、イオンビームスパッタリング法を用いてRu膜(膜厚2.5nm)と成膜することにより、保護層13を形成した。
Si膜の成膜条件
ターゲット:Siターゲット(ホウ素ドープ)
スパッタガス:Arガス(ガス圧0.02Pa)
電圧:700V
成膜速度:0.077nm/sec
膜厚:4.5nm
Mo膜の成膜条件
ターゲット:Moターゲット
スパッタガス:Arガス(ガス圧0.02Pa)
電圧:700V
成膜速度:0.064nm/sec
膜厚:2.3nm
Ru膜の成膜条件
ターゲット:Ruターゲット
スパッタガス:Arガス(ガス圧0.02Pa)
電圧:500V
成膜速度:0.023nm/sec
膜厚:2.5nm
吸収体層14(TaNH膜)は以下の方法で成膜した。膜組成は、X線光電子分光装置(X-ray Photoelectron Spectrometer)(PERKIN ELEMER-PHI社製)、二次イオン質量分析装置(Secondary Ion Mass Spectrometer)(PHI-ATOMIKA製)、ラザフォード後方散乱分光装置(Rutherford Back Scattering Spectroscopy)(神戸製鋼社製)を用いて測定する。吸収体層の組成は、Ta:N:H=55:42:3である。吸収体層におけるO含有率は0.05at%以下である。
吸収体層14(TaNH膜)の成膜条件
ターゲット:Taターゲット
スパッタガス:ArとN2とH2の混合ガス(Ar:89vol%、N2:8.3vol%、H2:2.7vol%、ガス圧:0.46Pa)
投入電力:300W
成膜速度:1.5nm/min
膜厚:70nm
低反射層15(TaONH膜)の成膜条件は以下の通りである。
低反射層15(TaONH膜)の成膜条件
ターゲット:Taターゲット
スパッタガス:ArとO2とN2とH2の混合ガス(Ar:48vol%、O2:36vol%、N2:14vol%、H2:2vol%、ガス圧:0.3Pa)
投入電力:450W
成膜速度:1.5nm/min
膜厚:10nm
(1)膜組成
低反射層15(TaONH膜)の組成を、X線光電子分光装置(X-ray Photoelectron Spectrometer)(PERKIN ELEMER-PHI社製)、ラザフォード後方散乱分光装置(Rutherford Back Scattering Spectroscopy)(神戸製鋼社製)を用いて測定する。低反射層の組成比(at%)は、Ta:O:N:H=22:65:5:8である。
吸収体層15(TaONH膜)の結晶状態を、X線回折装置(X-Ray Diffractmeter)(RIGAKU社製)で確認した。得られる回折ピークにはシャープなピークが見られないことから、低反射層15(TaONH膜)の結晶状態がアモルファス構造または微結晶構造であることを確認した。
低反射層15(TaONH膜)の表面粗さは、原子間力顕微鏡(SII社製、SPI-3800)を用いて、dynamic force modeで測定する。表面粗さの測定領域は1μm×1μmであり、カンチレバーには、SI-DF40(SII社製)を用いる。低反射層の表面粗さ(rms)は0.30nmである。
本実施例では、保護層13(Ru膜)まで形成した段階で、該保護層13表面におけるマスクパターンの検査光(波長257nm)の反射率を分光光度計(HITACH UV-4100)を用いて測定した。また、低反射層15(TaONH膜)を形成した後、該低反射層表面におけるマスクパターンの検査光の反射率を測定した。その結果、保護層13層表面での波長257nmに対する反射率は、56.0%であった。一方、低反射層15(TaONH膜)表面での波長257nmに対する反射率は、6.2%であり、15%以下であった。これらの結果と上記した式を用いてコントラストを求めたところ、波長257nmにおけるコントラストは79.9%であった。
マスクパターンの検査光の波長に対して、保護層13表面と低反射層15表面のコントラストは70%以上であり、十分なコントラストが得られた。得られたEUVマスクブランク1について、低反射層15(TaONH膜)表面にEUV光(波長13.5nm)を照射してEUV光の反射率を測定する。その結果、EUV光の反射率は0.4%である。
低反射層15(TaONH膜)表面の、400~1200nmの波長に対する反射率を分光光度計(HITACH UV-4100)を用いて測定した。所定の波長に対する反射率は下記の通りであった。
[目標値]
・405nm :<40%
・600~650nm :30~50%
・800~900nm :>50%
・1000~1200nm :<90%
[測定結果]
・405nm :27%
・600~650nm :44~46%
・800~900nm :51~55%
・1000~1200nm :<65%
いずれの波長に対しても、目標値の範囲内の反射率であった。
本実施例では、低反射層15をTaOHとした以外は、実施例1と同様の手順で実施し、基板11上に反射層12、保護層13、吸収体層14(TaNH)、低反射層15(TaOH)がこの順で形成されたEUVマスクブランク1を得る。低反射層15(TaOH)の組成比(at%)は、実施例1と同様の方法で測定した結果、Ta:O:H=30:61:9である。
低反射層15(TaOH)の成膜条件は以下の通りである。
低反射層15(TaOH膜)の成膜条件
ターゲット:Taターゲット
スパッタガス:ArとO2とH2混合ガス(Ar:60vol%、O2:37.3vol%、H2:2.7vol%、ガス圧:0.3Pa)
投入電力:450W
成膜速度:2.0nm/sec
膜厚:10nm
上記の手順で得られた低反射層15(TaOH膜)の結晶状態を、実施例1と同様の手順で調べたところ、結晶状態がアモルファス構造または微結晶構造であることを確認する。
次に、上記の手順で得られるEUVブランクスに対して、実施例1と同様に反射特性を評価する。低反射層15(TaOH膜)表面での波長257nmに対する反射率を実施例1と同様に評価したところ、5.9%であり、15%以下である。これらの結果から、波長257nmにおけるコントラストは80.9%である。
マスクパターンの検査光の波長に対して、保護層13表面と低反射層15表面のコントラストは70%以上であり、十分なコントラストが得られる。得られたEUVマスクブランク1について、低反射層15(TaOH膜)表面にEUV光(波長13.5nm)を照射してEUV光の反射率を測定する。その結果、EUV光の反射率は0.5%である。
次に、低反射層15(TaOH膜)表面の、400~1200nmの波長に対する反射率を実施例1と同様に評価する。所定の波長に対する反射率は下記の通りである。
[目標値]
・405nm :<40%
・600~650nm :30~50%
・800~900nm :>50%
・1000~1200nm :<90%
[測定結果]
・405nm :31%
・600~650nm :42~45%
・800~900nm :51~56%
・1000~1200nm :<65%
いずれの波長に対しても、目標値の範囲内の反射率である。
本実施例では、吸収体層14をTaN膜とする以外は、実施例1と同様の手順で実施する。吸収体層14(TaN)の組成比(at%)は、実施例1と同様の方法で測定した結果、Ta:N=55:45である。吸収体層におけるO含有率は0.05at%以下である。
吸収体層14(TaN)の成膜条件は以下の通りである。
TaN層の成膜条件
ターゲット:Taターゲット
スパッタガス:ArとN2の混合ガス(Ar:86vol%、N2:14vol%、ガス圧:0.37Pa)
投入電力:300W
成膜速度:1.1nm/min
膜厚:60nm
次に、吸収体層14上に、低反射層15(TaONH)を実施例1と同様の手順で形成し、基板11上に反射層12、保護層13、吸収体層14(TaN)、低反射層15(TaONH)がこの順で形成されたEUVマスクブランク1を得る。
上記の手順で得られるEUVブランクスに対して、実施例1と同様に反射特性を評価する。低反射層15(TaONH膜)表面での波長257nmに対する反射率を実施例1と同様に評価したところ、6.0%であり、15%以下である。これらの結果から、波長257nmにおけるコントラストは80.6%である。
マスクパターンの検査光の波長に対して、保護層13表面と低反射層15表面のコントラストは70%以上であり、十分なコントラストが得られる。得られたEUVマスクブランク1について、低反射層15(TaONH膜)表面にEUV光(波長13.5nm)を照射してEUV光の反射率を測定する。その結果、EUV光の反射率は0.5%である。
[目標値]
・405nm :<40%
・600~650nm :30~50%
・800~900nm :>50%
・1000~1200nm :<90%
[測定結果]
・405nm :30%
・600~650nm :43~46%
・800~900nm :51~56%
・1000~1200nm :<65%
いずれの波長に対しても、目標値の範囲内の反射率である。
本実施例では、吸収体層14をTaN膜とする以外は、実施例2と同様の手順で実施する。吸収体層14(TaN膜)は、実施例3と同様の手順で作製し、基板11上に反射層12、保護層13、吸収体層14(TaN)、低反射層15(TaOH)がこの順で形成されたEUVマスクブランク1を得る。
上記の手順で得られるEUVブランクスに対して、実施例1と同様に反射特性を評価する。低反射層15(TaOH膜)表面での波長257nmに対する反射率を実施例1と同様に評価したところ、6.1%であり、15%以下である。これらの結果から、波長257nmにおけるコントラストは80.3%である。
マスクパターンの検査光の波長に対して、保護層13表面と低反射層15表面のコントラストは70%以上であり、十分なコントラストが得られる。得られたEUVマスクブランク1について、低反射層15(TaOH膜)表面にEUV光(波長13.5nm)を照射してEUV光の反射率を測定する。その結果、EUV光の反射率は0.4%である。
次に、低反射層15(TaOH膜)表面の、400~1200nmの波長に対する反射率を実施例1と同様に評価する。所定の波長に対する反射率は下記の通りである。
[目標値]
・405nm :<40%
・600~650nm :30~50%
・800~900nm :>50%
・1000~1200nm :<90%
[測定結果]
・405nm :30%
・600~650nm :42~46%
・800~900nm :51~57%
・1000~1200nm :<65%
いずれの波長に対しても、目標値の範囲内の反射率である。
本実施例では、吸収体層14をTaBN膜とする以外は、実施例1と同様の手順で実施する。吸収体層14(TaBN)の組成比(at%)は、実施例1と同様の方法で測定した結果、Ta:B:N=50:10:40である。吸収体層におけるO含有率は0.05at%以下である。
吸収体層14(TaBN)の成膜条件は以下の通りである。
TaBN層の成膜条件
ターゲット:TaB化合物ターゲット(組成比:Ta80at%、B20at%)
スパッタガス:ArとN2の混合ガス(Ar:80vol%、N2:20vol%、ガス圧:0.46Pa)
投入電力:300W
成膜速度:1.2nm/min
膜厚:60nm
次に、吸収体層14上に、低反射層15(TaONH)を実施例1と同様の手順で形成し、基板11上に反射層12、保護層13、吸収体層14(TaBN)、低反射層15(TaONH)がこの順で形成されたEUVマスクブランク1を得る。
上記の手順で得られるEUVブランクスに対して、実施例1と同様に反射特性を評価する。低反射層15(TaONH膜)表面での波長257nmに対する反射率を実施例1と同様に評価したところ、6.3%であり、15%以下である。これらの結果から、波長257nmにおけるコントラストは79.7%である。
次に、低反射層15(TaONH膜)表面の、400~1200nmの波長に対する反射率を実施例1と同様に評価する。所定の波長に対する反射率は下記の通りである。
[目標値]
・405nm :<40%
・600~650nm :30~50%
・800~900nm :>50%
・1000~1200nm :<90%
[測定結果]
・405nm :29%
・600~650nm :42~46%
・800~900nm :51~56%
・1000~1200nm :<65%
いずれの波長に対しても、目標値の範囲内の反射率である。
本実施例では、吸収体層14をTaBNH膜とする以外は、実施例1と同様の手順で実施する。吸収体層14(TaBNH)の組成比(at%)は、実施例1と同様の方法で測定した結果、Ta:B:N:H=60:3:33:4である。吸収体層におけるO含有率は0.05at%以下である。
吸収体層14(TaBNH)の成膜条件は以下の通りである。
TaBNH層の成膜条件
ターゲット:TaB化合物ターゲット(組成比:Ta80at%、B20at%)
スパッタガス:ArとN2とH2の混合ガス(Ar:80vol%、N2:17.3vol%、H2:2.7vol%、ガス圧:0.46Pa)
投入電力:300W
成膜速度:1.5nm/min
膜厚:60nm
次に、吸収体層14上に、低反射層15(TaONH)を実施例1と同様の手順で形成し、基板11上に反射層12、保護層13、吸収体層14(TaBNH)、低反射層15(TaONH)がこの順で形成されたEUVマスクブランク1を得る。
上記の手順で得られるEUVブランクスに対して、実施例1と同様に反射特性を評価する。低反射層15(TaONH膜)表面での波長257nmに対する反射率を実施例1と同様に評価したところ、6.2%であり、15%以下である。これらの結果から、波長257nmにおけるコントラストは80.0%である。
次に、低反射層15(TaONH膜)表面の、400~1200nmの波長に対する反射率を実施例1と同様に評価する。所定の波長に対する反射率は下記の通りである。
[目標値]
・405nm :<40%
・600~650nm :30~50%
・800~900nm :>50%
・1000~1200nm :<90%
[測定結果]
・405nm :31%
・600~650nm :42~47%
・800~900nm :51~55%
・1000~1200nm :<65%
いずれの波長に対しても、目標値の範囲内の反射率である。
本比較では、低反射層15を水素(H)を含まず、タンタル(Ta)と酸素(O)と窒素(N)を含むTaON膜とした以外は、実施例1と同様の手順で実施した。低反射層15の組成比(at%)は、実施例1と同様の方法で測定した結果、Ta:O:N=24:70:6であった。
低反射層15(TaON膜)の成膜条件は以下の通りである。
低反射層15(TaON膜)の成膜条件
ターゲット:Taターゲット
スパッタガス:ArとO2とN2の混合ガス(Ar:36vol%、O2:50vol%、N2:14vol%、ガス圧:0.3Pa)
投入電力:450W
成膜速度:1.1nm/min
膜厚:10nm
低反射層15(TaON膜)表面での、波長257nmに対する反射率は、9.0%であり、15%以下であった。これらの結果と上記した式を用いてコントラストを求めたところ、波長257nmにおけるコントラストは72.3%であった。マスクパターンの検査光の波長に対して、保護層13表面と低反射層15表面のコントラストは70%以上であり、十分なコントラストが得られた。
低反射層15(TaON膜)表面での、波長400~1200nmに対する反射率は、下記の通りであった。
[目標値]
・405nm :<40%
・600~650nm :30~50
・800~900nm :>50%
・1000~1200nm :<90%
[測定結果]
・405nm :31%
・600~650nm :41~44%
・800~900nm :49~53%
・1000~1200nm :<65%
波長800~900nmに対して、十分な反射率が得られなかった。
なお、2008年10月30日に出願された日本特許出願2008-279899号の明細書、特許請求の範囲、図面及び要約書の全内容をここに引用し、本発明の明細書の開示として、取り入れるものである。
11:基板
12:反射層(多層反射膜)
13:保護層
14:吸収体層
15:低反射層
Claims (20)
- 基板上に、EUV光を反射する反射層と、EUV光を吸収する吸収体層と、マスクパターンの検査光(波長190~260nm)に対する低反射層と、が、この順に形成されたEUVリソグラフィ用反射型マスクブランクであって、
前記低反射層が、タンタル(Ta)、酸素(O)および水素(H)を少なくとも含有し、
前記低反射層において、TaおよびOの合計含有率が85~99.9at%であり、Hの含有率が0.1~15at%であることを特徴とするEUVリソグラフィ用反射型マスクブランク。 - 前記低反射層において、TaとOの組成比がTa:O=1:8~3:1である請求項1に記載のEUVリソグラフィ用反射型マスクブランク。
- 基板上に、EUV光を反射する反射層と、EUV光を吸収する吸収体層と、マスクパターンの検査光(波長190~260nm)に対する低反射層と、が、この順に形成されたEUVリソグラフィ用反射型マスクブランクであって、
前記低反射層が、タンタル(Ta)、酸素(O)、窒素(N)および水素(H)を少なくとも含有し、
前記低反射層において、Ta、OおよびNの合計含有率が85~99.9at%であり、Hの含有率が0.1~15at%であることを特徴とするEUVリソグラフィ用反射型マスクブランク。 - 前記低反射層において、Taと(O+N)の組成比がTa:(O+N)=1:8~3:1である請求項3に記載のEUVリソグラフィ用反射型マスクブランク。
- 前記低反射層表面の表面粗さ(rms)が、0.5nm以下である請求項1ないし4のいずれかに記載のEUVリソグラフィ用反射型マスクブランク。
- 前記低反射層表面の結晶構造が、アモルファスである請求項1ないし5のいずれかに記載のEUVリソグラフィ用反射型マスクブランク。
- 前記低反射層の膜厚が、3~30nmである請求項1ないし6のいずれかに記載のEUVリソグラフィ用反射型マスクブランク。
- 前記吸収体層が、タンタル(Ta)を主成分とする請求項1ないし7のいずれかに記載のEUVリソグラフィ用反射型マスクブランク。
- 前記吸収体層が、タンタル(Ta)を主成分とし、ハフニウム(Hf)、珪素(Si)、ジルコニウム(Zr)、ゲルマニウム(Ge)、硼素(B)、窒素(N)および水素(H)から選ばれる少なくとも1種類の元素を含む請求項1ないし8のいずれかに記載のEUVリソグラフィ用反射型マスクブランク。
- 前記吸収体層は、酸素(O)の含有率が25at%未満である請求項1ないし9のいずれかに記載のEUVリソグラフィ用反射型マスクブランク。
- 前記吸収体層および前記低反射層の合計膜厚が、30~200nmである請求項1ないし10のいずれかに記載のEUVリソグラフィ用反射型マスクブランク。
- 前記反射層と前記吸収体層との間に、前記吸収体層へのパターン形成時に前記反射層を保護するための保護層が形成されており、
前記マスクパターンの検査光の波長(190~260nm)に対する前記保護層表面での反射光と、前記低反射層表面での反射光と、のコントラストが、60%以上である請求項1ないし11のいずれかに記載のEUVリソグラフィ用反射型マスクブランク。 - 前記低反射層中の水素の含有量は、前記吸収体層中の水素の含有量よりも、1at%以上多い請求項1ないし12のいずれかに記載のEUVリソグラフィ用反射型マスクブランク。
- 前記マスクパターンの検査光の波長(190~260nm)に対する、前記低反射層表面の反射率が15%以下である請求項1ないし13のいずれかに記載のEUVリソグラフィ用反射型マスクブランク。
- 前記低反射層が、ヘリウム(He)、アルゴン(Ar)、ネオン(Ne)、クリプトン(Kr)、キセノン(Xe)のうち少なくともひとつを含む不活性ガスと、酸素(O)および水素(H)を含む雰囲気中でTaターゲットを用いたスパッタリング法を行うことにより形成される請求項1または2に記載のEUVリソグラフィ用反射型マスクブランク。
- 前記低反射層が、ヘリウム(He)、アルゴン(Ar)、ネオン(Ne)、クリプトン(Kr)、キセノン(Xe)のうち少なくともひとつを含む不活性ガスと、酸素(O)、窒素(N)および水素(H)を含む雰囲気中でTaターゲットを用いたスパッタリング法を行うことにより形成される請求項3または4に記載のEUVリソグラフィ用反射型マスクブランク。
- 基板上に、EUV光を反射する反射層、EUV光を吸収する吸収体層、および、マスクパターンの検査光(波長190~260nm)に対する低反射層をこの順に形成することによりEUVリソグラフィ用反射型マスクブランクを製造する方法であって、
前記低反射層が、ヘリウム(He)、アルゴン(Ar)、ネオン(Ne)、クリプトン(Kr)、キセノン(Xe)のうち少なくともひとつを含む不活性ガスと、酸素(O)および水素(H)を含む雰囲気中でTaターゲットを用いたスパッタリング法を行うことにより形成されることを特徴とするEUVリソグラフィ用反射型マスクブランクの製造方法。 - 基板上に、EUV光を反射する反射層、EUV光を吸収する吸収体層、および、マスクパターンの検査光(波長190~260nm)に対する低反射層をこの順に形成することによりEUVリソグラフィ用反射型マスクブランクを製造する方法であって、
前記低反射層が、ヘリウム(He)、アルゴン(Ar)、ネオン(Ne)、クリプトン(Kr)、キセノン(Xe)のうち少なくともひとつを含む不活性ガスと、酸素(O)、窒素(N)および水素(H)を含む雰囲気中でTaターゲットを用いたスパッタリング法を行うことにより形成されることを特徴とするEUVリソグラフィ用反射型マスクブランクの製造方法。 - 請求項1~16のいずれかに記載のEUVリソグラフィ用反射型マスクブランクの吸収体層および低反射層にパターニングを施したことを特徴とするEUVリソグラフィ用反射型マスク。
- 請求項19に記載のEUVリソグラフィ用反射型マスクを用いて、被露光体に露光を行うことにより半導体集積回路を製造することを特徴とする半導体集積回路の製造方法。
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WO2020256062A1 (ja) * | 2019-06-20 | 2020-12-24 | Hoya株式会社 | 反射型マスクブランク、反射型マスク、並びに反射型マスク及び半導体装置の製造方法 |
JPWO2020256062A1 (ja) * | 2019-06-20 | 2020-12-24 | ||
JP7002700B2 (ja) | 2019-06-20 | 2022-01-20 | Hoya株式会社 | 反射型マスクブランク、反射型マスク、並びに反射型マスク及び半導体装置の製造方法 |
US12019366B2 (en) | 2019-06-20 | 2024-06-25 | Hoya Corporation | Reflective mask blank, reflective mask, and method for manufacturing reflective mask and semiconductor device |
Also Published As
Publication number | Publication date |
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JPWO2010050520A1 (ja) | 2012-03-29 |
CN102203906B (zh) | 2013-10-09 |
US20110200920A1 (en) | 2011-08-18 |
KR101669690B1 (ko) | 2016-10-27 |
KR20110079618A (ko) | 2011-07-07 |
TWI434131B (zh) | 2014-04-11 |
TW201022838A (en) | 2010-06-16 |
JP5348141B2 (ja) | 2013-11-20 |
US8227152B2 (en) | 2012-07-24 |
CN102203906A (zh) | 2011-09-28 |
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