Pattern formation method and laminate

Abstract

To provide a pattern formation method capable of contributing to sensibility improvement while holding LWR of a resist upper layer film, and to provide a laminate.SOLUTION: A pattern formation method using an EUV lithography includes steps of: forming a resist upper layer film on at least one surface side of a base plate; irradiating the resist upper layer film with EUV light; and developing the resist upper layer film to form a pattern. In the pattern formation method, a multilayer reflection coating layer is included between the base plate and the resist upper layer film, and as the multilayer reflection coating layer, there is used a layer having a structure in which two or more kinds of materials having different refraction indexes n in a wavelength of the EUV light are alternately laminated.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a pattern forming method and a laminate. [Background technology]

[0002] As LSIs become more highly integrated and faster, pattern rules are becoming increasingly miniaturized. Logic devices used in smartphones and other devices are driving this miniaturization, and 10nm-node logic devices are being mass-produced using the ArF lithography multiple exposure (multi-patterning lithography) process.

[0003] Lithography for the next 7nm and 5nm nodes is facing problems such as high costs due to multiple exposures and problems with overlay accuracy in multiple exposures, and there are high hopes for the arrival of EUV lithography, which can reduce the number of exposures.

[0004] Extreme ultraviolet (EUV) light, with a wavelength of 13.5 nm, is less than one-tenth the wavelength of ArF excimer lasers (193 nm). Therefore, EUV lithography is expected to achieve high optical contrast and high resolution. Because EUV light has a short wavelength and high energy density, acid generators are exposed to a small number of photons. The number of photons in EUV exposure is said to be one-fourteenth that of ArF exposure. Problems with EUV exposure include degradation of line width roughness (LWR) and critical dimension uniformity (CDU) due to photon variations (Non-Patent Document 1). Furthermore, possible influences of uneven distribution and aggregation of base polymers and acid generators, and diffusion of acid generated from acid generators have also been pointed out.

[0005] To address this issue, it is possible to reduce the LWR by lowering the post-exposure bake (PEB) temperature, but this reduces the sensitivity of the EUV resist. Furthermore, increasing the amount of quencher added also reduces the LWR, but this method also reduces the sensitivity. For practical use of EUV resists, it is necessary to overcome the trade-off between sensitivity and LWR.

[0006] Various studies have been conducted to address the above-mentioned issues. Patent Document 1 reports a high-sensitivity laminated resist film in which a metal layer is disposed on a resist layer, which enhances the light irradiated onto the resist layer when exposed, in order to improve the sensitivity of the EUV resist. Patent Document 2 reports a pattern formation method using a resist underlayer film containing a sensitizer that absorbs EUV light and generates secondary electrons. However, these methods that utilize secondary electrons are difficult to control and can cause deterioration of the resist shape. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Special Publication No. 2021-508071 [Patent Document 2] Patent No. 5705103 [Non-patent literature]

[0008] [Non-Patent Document 1] SPIE Vol.3331 p.531 (1998) Summary of the Invention [Problem to be solved by the invention]

[0009] Many issues must be resolved before EUV lithography can be put into practical use as a mass production process for semiconductor devices. Among these, the characteristic that needs particular improvement is increasing sensitivity while maintaining LWR.

[0010] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a pattern forming method and a laminate that can contribute to improving sensitivity while maintaining the LWR of the resist top layer film. [Means for solving the problem]

[0011] In order to solve the above problems, the present invention provides a method for manufacturing a photoresist substrate, comprising the steps of: forming a resist top layer film on at least one surface of a substrate; irradiating the resist top layer film with EUV light; developing the resist top layer film to form a pattern; A pattern formation method using EUV lithography, comprising: a multilayer reflective film layer between the substrate and the resist top layer; The present invention provides a pattern forming method using, as the multilayer reflective film layer, a structure in which two or more types of materials with different refractive indices n at the wavelength of EUV light are alternately laminated.

[0012] Such a pattern formation method can contribute to improving sensitivity while maintaining the LWR of the resist top layer film.

[0013] In the present invention, it is preferable that the multilayer reflective film layer includes a structure in which two or more materials having refractive indices n at the wavelength of EUV light that differ by 0.01 or more are alternately laminated.

[0014] A pattern formation method using a multilayer reflective film layer having such a structure can contribute to improving sensitivity while maintaining the LWR of the resist top layer film.

[0015] In addition, in the present invention, it is preferable to use, as the multilayer reflective film layer, one or more high refractive index films made of a material containing Si and one or more elements selected from nitrogen, carbon, hydrogen, and oxygen, and one or more low refractive index films made of a material containing one or more metals selected from Ti, Cr, Ni, Zr, Nb, Mo, Ru, Rh, Hf, Ta, W, and Bi.

[0016] A pattern formation method using a multilayer reflective film layer with such a structure can further increase the reflectivity of EUV light, which can contribute to improving sensitivity while maintaining the LWR of the resist top layer film.

[0017] In addition, in the present invention, it is preferable to use, as the multilayer reflective film layer, one or more high refractive index films made of a material containing carbon and one or more elements selected from nitrogen, hydrogen, and oxygen, and one or more low refractive index films made of a material containing one or more metals selected from Ti, Cr, Ni, Zr, Nb, Mo, Ru, Rh, Hf, Ta, W, and Bi.

[0018] A pattern formation method using a multilayer reflective film layer with such a structure can further increase the reflectivity of EUV light, which can contribute to improving sensitivity while maintaining the LWR of the resist top layer film.

[0019] In the present invention, it is preferable to use a multilayer reflective film layer that includes two or more low refractive index films made of a material containing one or more metals selected from the group consisting of Ti, Cr, Ni, Zr, Nb, Mo, Ru, Rh, Hf, Ta, W, and Bi.

[0020] A pattern formation method using a multilayer reflective film layer with such a structure can further increase the reflectivity of EUV light, which can contribute to improving sensitivity while maintaining the LWR of the resist top layer film.

[0021] In this case, it is preferable that the low refractive index film has a refractive index n of 0.97 or less at the wavelength of the EUV light.

[0022] By using a film with such a refractive index, the reflectance of EUV light can be further increased.

[0023] In this case, it is preferable that the low refractive index film has a thickness of 10 nm or less per layer.

[0024] A multilayer reflective film layer having such a low refractive index film can further increase the reflectance of EUV light.

[0025] In the present invention, it is preferable that at least one adhesion film selected from a silicon-containing hard mask film made of a material containing Si and one or more elements selected from nitrogen, carbon, hydrogen, and oxygen, and a carbon-containing hard mask film made of a material containing carbon and one or more elements selected from nitrogen, hydrogen, and oxygen be included between the resist top layer film and the multilayer reflective film layer.

[0026] By including at least one adhesion film selected from a silicon-containing hard mask film and a carbon-containing hard mask film between the resist top layer film and the multilayer reflective film layer, it is possible to improve the effect of suppressing collapse of the resist top layer film pattern and the accuracy of pattern transfer to the processed layer.

[0027] In addition, the present invention preferably includes a step of transferring the pattern to the processing layer on the substrate by dry etching using the resist upper layer film on which the pattern has been formed as a mask.

[0028] Such a pattern forming method makes it possible to form a fine pattern on a workpiece (substrate) with high precision.

[0029] The present invention also provides a laminate comprising a substrate to be processed on which a pattern is to be formed, a multilayer reflective film layer on the substrate to be processed, and a resist top layer film on the multilayer reflective film layer, wherein the multilayer reflective film layer is formed by alternately laminating two or more types of materials having different refractive indices n at the wavelength of EUV light.

[0030] With such a laminate, it is possible to improve the sensitivity while maintaining the LWR of the resist upper layer film when a pattern is formed. [Effects of the Invention]

[0031] As described above, the pattern formation method of the present invention includes a multilayer reflective film layer having high reflectivity to EUV light, which makes it possible to effectively utilize EUV light in photolithography. Therefore, in EUV lithography using EUV light as exposure light, the resist top layer film can be made highly sensitive while maintaining the inherent LWR performance. [Brief explanation of the drawings]

[0032] [Figure 1] FIG. 1 is an explanatory diagram of an example of the pattern forming method of the present invention (processing of a processable layer). [Figure 2] FIG. 2 is an explanatory diagram of an example of a multilayer reflective film layer in the pattern formation method of the present invention. [Figure 3] FIG. 3 is an explanatory diagram of an example of a conventional pattern forming method (tri-layer process). DETAILED DESCRIPTION OF THE INVENTION

[0033] As described above, in the fine patterning process using the multilayer resist method, there has been a demand for the development of a pattern formation method and a laminate that can contribute to improving sensitivity while maintaining the LWR of the resist top layer film.

[0034] The present inventors have focused on a multilayer reflective film layer capable of reflecting EUV light and conducted extensive research. As a result, they have found that a structure including a multilayer reflective film layer between a resist top layer and a substrate, in which two or more materials having different refractive indices n at the wavelength of EUV light are stacked, can improve sensitivity while maintaining the inherent LWR performance of the resist top layer in EUV lithography using EUV light as exposure light, and have completed the present invention.

[0035] That is, the present invention provides a method for manufacturing a photoresist substrate, comprising the steps of: forming a resist top layer film on at least one surface of a substrate; irradiating the resist top layer film with EUV light; developing the resist top layer film to form a pattern; A pattern formation method using EUV lithography, comprising: a multilayer reflective film layer between the substrate and the resist top layer; The pattern forming method uses a multilayer reflective film layer having a structure in which two or more materials with different refractive indices n at the wavelength of EUV light are alternately laminated.

[0036] The present invention also provides a laminate comprising a substrate to be processed on which a pattern is to be formed, a multilayer reflective film layer on the substrate to be processed, and a resist top layer film on the multilayer reflective film layer, wherein the multilayer reflective film layer is formed by alternately stacking two or more types of materials having different refractive indices n at the wavelength of EUV light.

[0037] The present invention will be described in detail below, but the present invention is not limited thereto.

[0038] <Laminate> The laminate of the present invention comprises a substrate to be processed on which a pattern is to be formed, a multilayer reflective film layer on the substrate to be processed, and a resist top layer film on the multilayer reflective film layer, and the multilayer reflective film layer is formed by alternately laminating two or more materials having different refractive indices n at the wavelength of EUV light.

[0039] The substrate to be processed, the multilayer reflective film layer, and the resist upper layer film used in the laminate of the present invention can be the same as those used in the pattern forming method of the present invention described below.

[0040] <Pattern formation method using a multilayer reflective film layer> The present invention includes a step of forming a resist top layer film on at least one surface side of a substrate; irradiating the resist top layer film with EUV light; developing the resist top layer film to form a pattern; A pattern formation method using EUV lithography, comprising: a multilayer reflective film layer between the substrate and the resist top layer; The pattern forming method uses a multilayer reflective film layer having a structure in which two or more materials with different refractive indices n at the wavelength of EUV light are alternately laminated.

[0041] Such a pattern formation method has high reflectivity with respect to EUV light, and therefore the sensitivity of the resist upper layer film can be improved.

[0042] In the pattern formation method, the resist upper layer film may be either positive or negative, and the composition for forming the resist upper layer film may be the same as a commonly used photoresist composition. The photoresist composition may also contain metal atoms such as Sn, In, Ga, Ge, Al, Ce, La, Cs, Zr, Hf, Ti, Bi, Sb, and Zn. When forming the resist upper layer film using the photoresist composition, it may be formed by spin coating or by vapor deposition using a CVD method or an ALD method.

[0043] When forming a resist upper layer film by spin coating, the photoresist composition is applied and then prebaked, preferably at 60 to 180°C for 10 to 300 seconds. Then, exposure is performed according to a conventional method, followed by post-exposure baking (PEB) and development to obtain a resist upper layer film pattern. The thickness of the resist upper layer film is not particularly limited, but is preferably 10 to 500 nm, and more preferably 20 to 400 nm.

[0044] When the resist top layer is formed by deposition using a CVD or ALD method, the resist top layer can be an EUV-sensitive metal oxide-containing film, where the metal is selected from Sn, Zr, Hf, Ti, Bi, Sb, etc., with Sn being preferred due to its excellent EUV sensitivity. The metal oxide-containing film can be a photosensitive organometallic oxide-containing film such as an organotin oxide (e.g., haloalkyltin, alkoxyalkyltin, or amidoalkyltin). Specific examples of suitable precursors include trimethyltin chloride, dimethyltin dichloride, methyltin trichloride, tris(dimethylamino)methyltin(IV), and (dimethylamino)trimethyltin(IV).

[0045] Metal oxide-containing films may be deposited by PECVD or PEALD, for example, using a Lam Vector® tool. In the ALD example, the Sn oxide precursor is separated from the O precursor / plasma. The deposition temperature is preferably in the range of 50°C to 600°C. The deposition pressure is preferably between 100 and 6,000 mTorr. The metal oxide-containing film precursor liquid flow rate (e.g., organotin oxide precursor) may be 0.01 to 10 cm / s, and the gas flow rate (CO2, CO, Ar, N2) may be 100 to 10,000 sccm. The plasma power may be 200 to 1,000 W per 300 mm wafer station using a high frequency plasma (e.g., 13.56 MHz, 27.1 MHz, or higher). The deposition thickness is preferably 100 to 2,000 Å.

[0046] The wavelength of the EUV light used in EUV lithography, which uses EUV light as exposure light, is preferably 13 to 14 nm, and light with a wavelength of about 13.5 nm is more preferable.

[0047] In the pattern forming method, the development method is preferably alkaline development or development using an organic solvent.

[0048] The substrate (substrate to be processed) is not particularly limited, and may be a substrate such as Si, α-Si, p-Si, SiO2, SiN, SiON, W, TiN, or Al, or a substrate with a processable layer formed thereon. The processable layer may be a low-k film such as Si, SiO2, SiON, SiN, p-Si, α-Si, W, W-Si, Al, Cu, or Al-Si, or a stopper film thereof, and may be formed to a thickness of typically 50 to 10,000 nm, particularly 100 to 5,000 nm. When a processable layer is formed, the substrate and the processable layer are made of different materials.

[0049] The substrate may be a substrate for semiconductor manufacturing on which a layer to be processed (portion to be processed) made of a metal film, a metal carbide film, a metal oxide film, a metal nitride film, or a composite of these films is formed.

[0050] Silicon substrates are generally used as substrates for semiconductor manufacturing, but are not particularly limited thereto, and substrates made of a material different from the layer to be processed, such as Si, amorphous silicon (α-Si), p-Si, SiO2, SiN, SiON, W, TiN, and Al, may also be used.

[0051] The metal constituting the work layer can be any of silicon, titanium, tungsten, hafnium, zirconium, chromium, germanium, copper, aluminum, and iron, or an alloy thereof. Examples of work layers containing such metals include Si, SiO2, SiN, SiON, SiOC, p-Si, α-Si, TiN, WSi, BPSG, SOG, Cr, CrO, CrON, MoSi, W, W-Si, Al, Cu, and Al-Si, as well as various low dielectric films and their etching stopper films, and can be formed to a thickness of typically 50 to 10,000 nm, and particularly 100 to 5,000 nm.

[0052] In the pattern formation method of the present invention, in order to increase the reflectance to EUV light, a multilayer reflective film layer having a structure in which two or more materials having different refractive indices n at the wavelength of EUV light are alternately laminated is used.

[0053] The refractive index n in the EUV region can be obtained from BL Henke, EM Gullikson and JC Viss, X-ray interactions: photoabsorption, scattering, transmission and reflection at E=50-30,000 eV, Z=1-92, Atomic Data and Nuclear Data Tables Vol. 54 (No. 2), 181-342 (July 1993). In fact, to calculate specific values, please refer to the CXRO (The Center for X-ray Optics) web page.<http: / / henke.lbl.gov / optical_constants / getdb2.html> was used.

[0054] The multilayer reflective film preferably includes a structure in which two or more materials having refractive indices n at the wavelength of EUV light that differ by 0.01 or more are alternately laminated.

[0055] If the refractive index n of the multilayer reflective film layers differs by 0.01 or more, the reflectance of EUV light increases in EUV lithography using EUV light as exposure light, and the sensitivity of the resist can be improved.

[0056] The difference in refractive index n between the multilayer reflective film layers is preferably 0.01 or more, more preferably 0.02 or more, even more preferably 0.03 or more, and particularly preferably 0.04 or more. The upper limit is preferably 0.15 or less, more preferably 0.1 or less.

[0057] As long as the difference in refractive index n of the multilayer reflective film layer is 0.01 or more, the film species (element composition ratio) in each layer may be the same or different, but from the viewpoint of etching processing, it is preferable that the film species in each layer be the same.

[0058] The multilayer reflective film preferably has one or more high refractive index films made of a material containing Si and one or more elements selected from nitrogen, carbon, hydrogen, and oxygen, and one or more low refractive index films made of a material containing one or more metals selected from Ti, Cr, Ni, Zr, Nb, Mo, Ru, Rh, Hf, Ta, W, and Bi.

[0059] The high refractive index film containing Si is preferably a film made of a material containing Si and one or more elements selected from nitrogen, carbon, hydrogen, and oxygen, and the Si content in the high refractive index film is preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, and particularly preferably 30% by mass or more.

[0060] A higher Si content is preferable because the refractive index n can be increased as the Si content increases.

[0061] The high-refractive-index film containing Si can be a polysiloxane-based silicon-containing resist intermediate film or an inorganic hard mask intermediate film selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film. When forming an inorganic hard mask intermediate film, a silicon oxide film, a silicon nitride film, or a silicon oxynitride film (SiON film) can be formed by a CVD method, an ALD method, or the like. For example, methods for forming a silicon nitride film are described in JP 2002-334869 A and WO 2004 / 066377 A.

[0062] When the high-refractive-index film containing Si is formed by spin coating, the spin coating is followed by baking (heat treatment) to evaporate the solvent, prevent mixing with the overlying film, and promote the crosslinking reaction. Baking is preferably performed at a temperature of 100°C to 600°C for 10 to 600 seconds, more preferably at a temperature of 200°C to 500°C for 10 to 300 seconds. Considering the effects on device damage and wafer deformation, the upper limit of the heating temperature in the lithography wafer process is preferably 600°C or less, more preferably 500°C or less.

[0063] The multilayer reflective film preferably has one or more high refractive index films made of a material containing carbon and one or more elements selected from nitrogen, hydrogen, and oxygen, and one or more low refractive index films made of a material containing one or more metals selected from Ti, Cr, Ni, Zr, Nb, Mo, Ru, Rh, Hf, Ta, W, and Bi.

[0064] The high refractive index film containing carbon is preferably a film made of a material containing carbon and one or more elements selected from nitrogen, hydrogen, and oxygen, and the carbon content in the high refractive index film is preferably 60 mass % or more, more preferably 70 mass % or more, even more preferably 80 mass % or more, and particularly preferably 85 mass % or more.

[0065] A higher carbon content is preferable because the refractive index n can be increased as the carbon content increases.

[0066] The carbon-containing high refractive index film can be formed using a coating-type resist underlayer film material. Examples of coating-type resist underlayer film materials include those disclosed in International Publication Nos. 2007 / 105776, 2009 / 072465, 2010 / 061774, 2010 / 147155, 2011 / 125839, 2012 / 050064, 2012 / 077640, 2013 / 005797, 2013 / 047106, 2013 / 047516, 2013 / 080929, 2013 / 115097, and 2014 / 115098. No. 2013 / 146670, International Publication No. 2014 / 024836, International Publication No. 2014 / 208324, International Publication No. 2014 / 208499, International Publication No. 2015 / 170736, International Publication No. 2015 / 194273, International Publication No. 2016 / 147989, JP 2001-040293 A, JP 2002-214777 A, JP 2002-296789 A, JP 2004-205685 A, JP 2004-264710 A, JP 2005-043471 A, JP 2005-250434 A , JP 2005-128509 A, JP 2006-259249 A, JP 2006-285046 A, JP 2007-171895 A, JP 2007-199653 A, JP 2007-293294 A, JP 2008-065303 A, JP 2008-065081 A, JP 2008-274250 A, JP 2009-014816 A, JP 2009-229666 A, JP 2009-251130 A, JP 2010-122656 A, JP 2010-015112 A , JP 2010-271654 A, JP 2011-107684 A, JP 2011-170059 A, JP 2012-001687 A, JP 2012-077295 A, JP 2012-214720 A, JP 2012-215842 A, JP 2013-083939 A, JP 2014-024831 A, JP 2014-157169 A, JP 2015-131954 A, JP 2015-183406 A, JP 2016-029160 A, JP 2016-044272 A,Examples of resins and compositions include those disclosed in JP 2016-060886 A, JP 2016-145849 A, JP 2016-167047 A, JP 2016-216367 A, JP 2017-003959 A, JP 2017-119670 A, JP 2017-119671 A, JP 2013-516643 A, JP 2015-515112 A, and JP 2019-044022 A. In the present invention, preferred are resins containing aromatic skeleton-containing compounds such as naphthalene skeleton-containing compounds, fluorene skeleton-containing compounds, carbazole skeleton-containing compounds, acenaphthylene skeleton-containing compounds, naphthol skeleton-containing compounds, and bisnaphthol skeleton-containing compounds.

[0067] When the carbon-containing high refractive index film is formed by spin coating, the spin coating is followed by baking (heat treatment) to evaporate the solvent, prevent mixing with the overlying film, and promote the crosslinking reaction. Baking is preferably performed at a temperature of 100°C to 600°C for 10 to 600 seconds, more preferably at a temperature of 200°C to 500°C for 10 to 300 seconds. Considering the effects on device damage and wafer deformation, the upper limit of the heating temperature in the lithography wafer process is preferably 600°C or less, more preferably 500°C or less.

[0068] Alternatively, a resist underlayer film can be formed as the high refractive index film containing carbon by coating a resist underlayer film-forming composition on a workpiece layer by spin coating or the like, as described above, and then curing the resist underlayer film-forming composition by baking it in an atmosphere having an oxygen concentration of 0.1% by volume or more and 21% by volume or less.

[0069] By baking the resist underlayer film-forming composition in such an oxygen atmosphere, a sufficiently cured resist underlayer film can be obtained. Although air may be used as the atmosphere during baking, it is preferable to seal in an inert gas such as N2, Ar, or He to reduce oxygen and prevent oxidation of the resist underlayer film. To prevent oxidation, the oxygen concentration must be controlled, preferably to 1,000 ppm or less, more preferably 100 ppm or less (volume basis). Preventing oxidation is preferable because it prevents increased absorption and reduced etching resistance.

[0070] Alternatively, amorphous carbon or diamond-like carbon formed by the PVD method, CVD method, or ALD method can also be used.

[0071] The multilayer reflective film preferably includes two or more low refractive index films made of a material containing one or more metals selected from the group consisting of Ti, Cr, Ni, Zr, Nb, Mo, Ru, Rh, Hf, Ta, W, and Bi.

[0072] From the viewpoint of etching selectivity with respect to the metal-containing film that becomes the low refractive index film, the high refractive index film contained in the multilayer reflective film layer is more preferably a material containing carbon and one or more elements selected from nitrogen, hydrogen, and oxygen.

[0073] A low refractive index film made of a material containing one or more metals selected from Ti, Cr, Ni, Zr, Nb, Mo, Ru, Rh, Hf, Ta, W, and Bi can be formed by a method such as spin coating, PVD (physical vapor deposition), CVD (chemical vapor deposition), or ALD (atomic layer deposition).

[0074] The low refractive index film containing the metal is not particularly limited as long as it contains one or more metals selected from Ti, Cr, Ni, Zr, Nb, Mo, Ru, Rh, Hf, Ta, W, and Bi. It may be a metal film alone, or may contain one or more elements selected from nitrogen, carbon, and oxygen in addition to the metal. Examples include metal-containing films containing two or more elements selected from nitrogen, carbon, and oxygen, such as oxide films, nitride films, carbide films, oxycarbonate films, and oxynitride films containing the metals. It may contain multiple types of metals, and in this case, it is preferable for the metal-containing film to contain two or more metal elements.

[0075] Such a metal-containing film can be provided as a low refractive index film having a low refractive index n for EUV light, thereby further improving the reflectance.

[0076] The metal-containing low refractive index film is preferably an amorphous film, since an amorphous film does not deteriorate the line width roughness (LWR) of the pattern when etched.

[0077] When a metal oxide film is used as the low refractive index film, it is preferable to use a spin coating method using a metal-containing film-forming composition described later from the viewpoint of productivity. When a metal monolayer film, a metal nitride film, a metal carbide film, or the like is used as the low refractive index film, it is preferable to use a PVD method, a CVD method, or an ALD method.

[0078] When using spin coating, after spin coating, the solvent is evaporated and baking (heat treatment) is performed to promote the crosslinking reaction and prevent mixing with the resist upper layer film and resist intermediate film. Baking is preferably performed at 100°C or higher and 600°C or lower for 10 to 600 seconds, and more preferably at 200°C or higher and 500°C or lower for 10 to 300 seconds. Considering the effects on device damage and wafer deformation, the upper limit of the heating temperature in the lithography wafer process is preferably 600°C or lower, and more preferably 500°C or lower.

[0079] Alternatively, the metal-containing film can be formed by coating the metal-containing film-forming composition by spin coating or the like, as described above, and curing it by baking in an atmosphere with an oxygen concentration of 0.1% by volume or more and 21% by volume or less.

[0080] By baking the metal-containing film-forming composition in such an oxygen atmosphere, a fully cured metal-containing film can be obtained. Although air can be used as the atmosphere during baking, it is preferable to seal in an inert gas such as N2, Ar, or He to reduce oxygen and prevent oxidation of the metal-containing film. To prevent oxidation, the oxygen concentration must be controlled, preferably to 1,000 ppm or less, more preferably 100 ppm or less (volume basis). Preventing oxidation of the metal-containing film during baking is preferable because it prevents increased absorption and reduced etching resistance.

[0081] Examples of the metal-containing film-forming composition include the following.

[0082] <Metal-containing film forming composition> The metal-containing film-forming composition preferably contains (A) a metal compound and (B) a solvent, and the (A) metal compound preferably contains one or more of Ti, Cr, Ni, Zr, Nb, Mo, Ru, Rh, Hf, Ta, W, and Bi. The metal-containing film-forming composition may contain optional components depending on the object of the present invention. Each component will be described below.

[0083] <(A) Metal compounds> The (A) metal compound is not particularly limited, and any known metal compound, whether organic or inorganic, can be used. The metal compound is preferably a metal salt, a metal complex, or a combination thereof. Metal salts and metal complexes also include hydrates.

[0084] The (A) metal compound preferably contains one or more of the following metals: Ti, Cr, Ni, Zr, Nb, Mo, Ru, Rh, Hf, Ta, W, and Bi. By using the (A) metal compound as a metal atom of one of the above elements, the metal-containing film formed from the metal-containing film-forming composition has a low refractive index with respect to EUV light. The metal atoms may be composed of atoms of one element or atoms of two or more elements. However, from the viewpoint of ensuring in-plane uniformity on the nanometer order in the etching rate during etching transfer processing of the metal-containing film after micropattern formation, the metal atoms are preferably composed of atoms of one element.

[0085] The components other than the metal atom that constitute the (A) metal compound preferably include one or more ligands derived from a compound containing one or more selected from the group consisting of a hydrolyzable group, an organic acid (hereinafter also referred to as "(a) organic acid"), a hydroxy acid ester, a β-diketone, a β-ketoester, an α,α-dicarboxylic acid ester, an amine, an amide, an olefin, a π-bond-containing hydrocarbon, and a diphosphine. Here, "organic acid" refers to an organic compound that exhibits acidity, and "organic compound" refers to a compound having at least one carbon atom.

[0086] Examples of the hydrolyzable group include a halogen atom, an alkoxy group, and an acyloxy group.

[0087] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0088] The alkoxy group is preferably an alkoxy group having 1 to 10 carbon atoms, and examples thereof include a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, a butoxy group, and an octyl group.

[0089] Examples of the acyloxy group include an acetoxy group, an ethyryloxy group, a propionyloxy group, a butyryloxy group, a t-butyryloxy group, a t-amylyloxy group, an n-hexanecarbonyloxy group, and an n-octanecarbonyloxy group.

[0090] The hydrolyzable group is preferably an alkoxy group or an acyloxy group, and more preferably an n-propoxy group, an i-propoxy group, a butoxy group, or an octyl group.

[0091] (a) Examples of organic acids include carboxylic acids, sulfonic acids, sulfinic acids, organic phosphinic acids, organic phosphonic acids, phenols, enols, thiols, acid imides, oximes, and sulfonamides.

[0092] Examples of the carboxylic acid include monocarboxylic acids such as formic acid, acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, 2-ethylhexanoic acid, oleic acid, acrylic acid, methacrylic acid, trans-2,3-dimethylacrylic acid, stearic acid, linoleic acid, linolenic acid, arachidonic acid, salicylic acid, benzoic acid, p-aminobenzoic acid, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, trifluoroacetic acid, pentafluoropropionic acid, gallic acid, and shikimic acid; dicarboxylic acids such as oxalic acid, malonic acid, maleic acid, methylmalonic acid, fumaric acid, adipic acid, sebacic acid, phthalic acid, and tartaric acid; and carboxylic acids having three or more carboxy groups, such as citric acid.

[0093] Examples of the sulfonic acid include benzenesulfonic acid and p-toluenesulfonic acid.

[0094] Examples of the sulfinic acid include benzenesulfinic acid and p-toluenesulfinic acid.

[0095] Examples of the organic phosphinic acid include diethylphosphinic acid, methylphenylphosphinic acid, and diphenylphosphinic acid.

[0096] Examples of the organic phosphonic acid include methylphosphonic acid, ethylphosphonic acid, t-butylphosphonic acid, cyclohexylphosphonic acid, and phenylphosphonic acid.

[0097] Examples of the phenols include monohydric phenols such as phenol, cresol, 2,6-xylenol, and naphthol; dihydric phenols such as catechol, resorcinol, hydroquinone, and 1,2-naphthalenediol; and trihydric or higher phenols such as pyrogallol and 2,3,6-naphthalenetriol.

[0098] Examples of the enol include 2-hydroxy-3-methyl-2-butene and 3-hydroxy-4-methyl-3-hexene.

[0099] Examples of the thiol include mercaptoethanol and mercaptopropanol.

[0100] Examples of the acid imide include carboxylic acid imides such as maleimide and succinimide, and sulfonic acid imides such as di(trifluoromethanesulfonic acid)imide and di(pentafluoroethanesulfonic acid)imide.

[0101] Examples of the oxime include aldoximes such as benzaldoxime and salicylaldoxime, and ketoximes such as diethylketoxime, methylethylketoxime and cyclohexanoneoxime.

[0102] Examples of the sulfonamide include methylsulfonamide, ethylsulfonamide, benzenesulfonamide, and toluenesulfonamide.

[0103] (a) The organic acid is preferably a carboxylic acid having 1 to 10 carbon atoms.

[0104] Examples of the hydroxy acid ester include glycolic acid ester, lactic acid ester, 2-hydroxycyclohexane-1-carboxylic acid ester, salicylic acid ester, and the like.

[0105] Examples of the β-diketone include 2,4-pentanedione, 3-methyl-2,4-pentanedione, and 3-ethyl-2,4-pentanedione.

[0106] Examples of the β-ketoester include acetoacetic ester, α-alkyl-substituted acetoacetic ester, β-ketopentanoic ester, benzoylacetic ester, and 1,3-acetonedicarboxylic ester.

[0107] Examples of the α,α-dicarboxylic acid ester include malonic acid diester, α-alkyl-substituted malonic acid diester, α-cycloalkyl-substituted malonic acid diester, and α-aryl-substituted malonic acid diester.

[0108] Examples of the amine compound include pyridine, trimethylamine, piperidine, diethanolamine, and triethanolamine.

[0109] Examples of compounds containing amide include compounds containing unsubstituted amide (NH2), methylamide (NHMe), dimethylamide (NMe2), diethylamide (NEt2), dipropylamide (NPr2), and the like.

[0110] Examples of the olefin-containing compound include chain olefins such as ethylene and propylene, and cyclic olefins such as cyclopentene, cyclohexene and norbornene.

[0111] Examples of the π-bond-containing hydrocarbon include chain dienes such as butadiene and isoprene, cyclic dienes such as cyclopentadiene, methylcyclopentadiene, pentamethylcyclopentadiene, cyclohexadiene and norbornadiene, and aromatic hydrocarbons such as benzene, toluene, xylene, hexamethylbenzene, naphthalene and indene.

[0112] Examples of the diphosphines include 1,1-bis(diphenylphosphino)methane, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl, and 1,1′-bis(diphenylphosphino)ferrocene.

[0113] Preferred examples of the (A) metal compound include the following.

[0114] Examples of compounds containing Ti include diisopropoxybis(2,4-pentanedionato)titanium(IV), tetra-n-butoxytitanium(IV), tetra-n-propoxytitanium(IV), tetraisopropoxytitanium(IV), tri-n-butoxymonostearatetitanium(IV), tetrakis(2-ethylhexyl) orthotitanate, dihydroxybis(hydrogen lactato)titanium(IV), titanium(IV) butoxide oligomer, aminopropyltrimethoxytitanium(IV), triethoxymono(2,4-pentanedionato)titanium(IV), tri-n-propoxymono(2,4-pentanedionato)titanium(IV), triisopropoxymono(2,4-pentanedionato)titanium, and di-n-butoxybis(2,4-pentanedionato)titanium(IV).

[0115] Examples of compounds containing Cr include chromium(III) tris(2-ethylhexanoate), chromium(III) tris(2,4-pentanedionato), chromium(III) tris(trifluoro-2,4-pentanedionato), chromium(III) pyridine-2-carboxylate, chromium(III) chloride, and chromium(II) chloride.

[0116] Examples of compounds containing Ni include nickel(II) acetate, nickel chloride, nickel(II) 2-ethylhexanoate, bis(2,4-pentanedionato)nickel(II) hydrate, bis(hexafluoroacetylacetonato)nickel(II), 2-amino-5-methylbenzenesulfonate nickel(II), and nickel(II) trifluoromethanesulfonate.

[0117] Compounds containing Zr include dibutoxybis(ethylacetoacetate)zirconium(IV), di-n-butoxybis(2,4-pentanedionato)zirconium(IV), tetra-n-butoxyzirconium(IV), tetra-n-propoxyzirconium(IV), tetraisopropoxyzirconium(IV), aminopropyltriethoxyzirconium(IV), 2-(3,4-epoxycyclohexyl)ethyltrimethoxyzirconium(IV), γ-glycidoxypropyltrimethoxyzirconium(IV), 3-isocyanopropyltrimethoxyzirconium(IV), and triethoxymono(2,4-pentanedionato). Examples of suitable oxidizing agents include zirconium(IV), tri-n-propoxymono(2,4-pentanedionato)zirconium(IV), triisopropoxymono(2,4-pentanedionato)zirconium(IV), tri(3-methacryloxypropyl)methoxyzirconium(IV), tri(3-acryloxypropyl)methoxyzirconium(IV), zirconium acetate(IV), zirconium acetate oxide(IV), bis(2-ethylhexanoate)zirconium(II), tetra(2-ethylhexanoate)zirconium(IV), bis(2-ethylhexanoate)oxozirconium(IV), zirconium nitrate, and zirconium chloride(IV).

[0118] Examples of compounds containing Nb include niobium(V) ethoxide, niobium n-butoxide, niobium phenoxide, tetrakis(2,2,6,6-tetramethyl-3,5-heptanedionato)niobium(IV), pentakis(dimethylamino)niobium(V), niobium(V) chloride, niobium(V) fluoride, niobium(III) triacetate, and niobium(IV) 2-ethylhexanoate.

[0119] Compounds containing Mo include pentaethoxymolybdenum(V), molybdenum(VI) hexaethoxide, molybdenum(V) isopropoxide, molybdenum(II) acetate dimer, bis(acetylacetonato)molybdenum(IV) oxide, bis(2,2,6,6-tetramethyl-3,5-heptanedionato)molybdenum(VI) oxide, molybdenum 2-ethylhexanoate, molybdenum(V) chloride, and molybdenum(III) chloride.

[0120] Examples of compounds containing Ru include diacetato[(S)-(-)-2,2'-bis(diphenylphosphino)-1,1'-binaphthyl]ruthenium(II), tris(2,4-pentanedionato)ruthenium(III), bis(2,2,6,6-tetramethyl-3,5-heptanedionato)(1,5-cyclooctadiene)ruthenium(II), ruthenium chloride(III), bis(ethylcyclopentadienyl)ruthenium(II), dichloro(1,5-cyclooctadiene)ruthenium(II), and pentamethylcyclopentadienylruthenium(III) chloride polymer.

[0121] Rh-containing compounds include acetylacetonatobis(ethylene)rhodium(I), (acetylacetonato)(norbornadiene)rhodium(I), dirhodium(II) tetraacetate, tetrakis(octanoato)dirhodium(II), rhodium(III) chloride, rhodium(III) nitrate, rhodium(II) acetate dimer, rhodium(II) trimethylacetate dimer, rhodium(II) trifluoroacetate dimer, rhodium(II) octanoate dimer, rhodium(II) triphenylacetate dimer, acetylacetonatobis(ethylene)rhodium(I), (acetylacetonato)(norbornadiene)rhodium(I), and (acetylacetonato)(1,5-cyclooctadiene)rhodium(I).

[0122] Examples of compounds containing Hf include diisopropoxybis(2,4-pentanedionato)hafnium(IV), tetrabutoxyhafnium(IV), tetraisopropoxyhafnium(IV), tetraethoxyhafnium(IV), dichlorobis(cyclopentadienyl)hafnium(IV), hafnium chloride(IV), tetrakis(dimethylamido)hafnium(IV), tetrakis(ethylmethylamido)hafnium(IV), hafnium carboxyethyl acrylate, bis(cyclopentadienyl)hafnium(IV) dichloride, and hafnium(IV) trifluoromethanesulfonate hydrate.

[0123] Compounds containing Ta include tantalum(V) methoxide, tantalum(V) ethoxide, tetrabutoxytantalum(IV), pentabutoxytantalum(V), pentaethoxytantalum(V), tantalum(V) chloride, pentakis(dimethylamino)tantalum(V), tris(diethylamido)(tert-butylimido)-tantalum(V), and bis(2-ethylhexanoate)tantalum(II).

[0124] Compounds containing W include tungsten(VI) ethoxide, tetrabutoxytungsten(IV), pentabutoxytungsten(V), pentamethoxytungsten(V), hexabutoxytungsten(VI), hexaethoxytungsten(VI), and dichlorobis(cyclopentadienyl)tungsten(IV).

[0125] Examples of compounds containing Bi include bismuth(III)-n-butoxide, tri-t-amyloxybismuth(III), triethoxybismuth(III), bismuth(III) tris(β-diketonate), bismuth(III) neodecanoate, tris(2-naphthol)bismuth(III), bismuth fluoride(III), bismuth(III) bromide, bismuth(III) iodide, bismuth(III) oxychloride, bismuth(III) acetate, bismuth(III) subsalicylate, bismuth(III) 2-ethylhexanoate, and bismuth(III) trifluoromethanesulfonate.

[0126] Specific examples of the metal compound (A) include compounds represented by the following general formula (A-1): By using such a metal compound (A-1), a metal-containing film-forming composition containing the metal compound (A-1) can form a stable metal-containing film and improve dry etching resistance. [ka] In the general formula (A-1), M is at least one of Ti, Cr, Ni, Zr, Nb, Mo, Ru, Rh, Hf, Ta, W, and Bi. L is a monodentate or polydentate ligand having 0 to 30 carbon atoms. X is a halogen atom, an alkoxy group, a carboxylate group, an acyloxy group, or -NR A R B R is a hydrolyzable group selected from A and R B are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. a+c=an integer of 1 to 6, a is an integer of 0 to 4, b is an integer of 0 to 2, and c is an integer of 0 to 6.

[0127] The hydrolyzable group X in the general formula (A-1) is a halogen atom, an alkoxy group, a carboxylate group, an acyloxy group, or —NR A R B Examples include: R A and R B are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms.

[0128] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0129] Examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, and a t-butoxy group.

[0130] Examples of the carboxylate group include monocarboxylic acids such as formic acid, acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, 2-ethylhexanoic acid, oleic acid, acrylic acid, methacrylic acid, trans-2,3-dimethylacrylic acid, stearic acid, linoleic acid, linolenic acid, arachidonic acid, salicylic acid, benzoic acid, p-aminobenzoic acid, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, trifluoroacetic acid, pentafluoropropionic acid, gallic acid, and shikimic acid; dicarboxylic acids such as oxalic acid, malonic acid, maleic acid, methylmalonic acid, fumaric acid, adipic acid, sebacic acid, phthalic acid, and tartaric acid; and carboxylic acids having three or more carboxylate groups, such as citric acid.

[0131] Examples of the acyloxy group include an acetoxy group, an ethyryloxy group, a propionyloxy group, a butyryloxy group, a t-butyryloxy group, a t-amylyloxy group, an n-hexanecarbonyloxy group, and an n-octanecarbonyloxy group.

[0132] Above -NR A R B Examples of the amino group include an unsubstituted amino group, a methylamino group, a dimethylamino group, a diethylamino group, and a dipropylamino group.

[0133] The hydrolyzable group X is preferably an alkoxy group, more preferably an i-propoxy group, an n-butoxy group, or a t-butoxy group.

[0134] In the above general formula (A-1), L is a monodentate or polydentate ligand having 0 to 30 carbon atoms.

[0135] (monodentate ligand) Examples of the monodentate ligand include a hydroxo ligand, a carboxy ligand, an amide ligand, an amine ligand, and an olefin ligand.

[0136] Examples of the carboxy ligand include ligands derived from monocarboxylic acids such as formic acid, acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, 2-ethylhexanoic acid, oleic acid, acrylic acid, methacrylic acid, trans-2,3-dimethylacrylic acid, stearic acid, linoleic acid, linolenic acid, arachidonic acid, salicylic acid, benzoic acid, p-aminobenzoic acid, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, trifluoroacetic acid, pentafluoropropionic acid, gallic acid, and shikimic acid; ligands derived from dicarboxylic acids such as oxalic acid, malonic acid, maleic acid, methylmalonic acid, fumaric acid, adipic acid, sebacic acid, phthalic acid, and tartaric acid; and ligands derived from carboxylic acids having three or more carboxy groups, such as citric acid.

[0137] Examples of the amide ligand include an unsubstituted amide ligand (NH2), a methylamide ligand (NHMe), a dimethylamide ligand (NMe2), a diethylamide ligand (NEt2), and a dipropylamide ligand (NPr2).

[0138] Examples of the amine ligand include pyridine, trimethylamine ligand, and piperidine ligand.

[0139] Examples of the olefin ligand include chain olefins such as ethylene and propylene, and cyclic olefins such as cyclopentene, cyclohexene and norbornene.

[0140] (polydentate ligand) Examples of the polydentate ligand include a ligand derived from a hydroxy acid ester, a ligand derived from a β-diketone, a ligand derived from a β-ketoester, a ligand derived from an α,α-dicarboxylic acid ester, a hydrocarbon having a π bond, and a diphosphine.

[0141] Examples of the hydroxy acid ester include glycolic acid ester, lactic acid ester, 2-hydroxycyclohexane-1-carboxylic acid ester, salicylic acid ester, and the like.

[0142] Examples of the β-diketone include 2,4-pentanedione, 3-methyl-2,4-pentanedione, and 3-ethyl-2,4-pentanedione.

[0143] Examples of the β-ketoester include acetoacetic ester, α-alkyl-substituted acetoacetic ester, β-ketopentanoic ester, benzoylacetic ester, and 1,3-acetonedicarboxylic ester.

[0144] Examples of the α,α-dicarboxylic acid ester include malonic acid diester, α-alkyl-substituted malonic acid diester, α-cycloalkyl-substituted malonic acid diester, and α-aryl-substituted malonic acid diester.

[0145] Examples of the hydrocarbon having a π bond include chain dienes such as butadiene and isoprene, cyclic dienes such as cyclopentadiene, methylcyclopentadiene, pentamethylcyclopentadiene, cyclohexadiene and norbornadiene, and aromatic hydrocarbons such as benzene, toluene, xylene, hexamethylbenzene, naphthalene and indene.

[0146] Examples of the diphosphines include 1,1-bis(diphenylphosphino)methane, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl, and 1,1'-bis(diphenylphosphino)ferrocene.

[0147] The (A) metal compound may be, for example, an anion of an oxoacid (phosphate ion, sulfate ion, chromate ion, tungstate ion (WO4 2- ), molybdate ion (MoO4 2- ) or a compound containing an inorganic anion such as a polyacid anion formed by condensation of a plurality of oxo acids, or a mixture thereof.

[0148] The polyacid may be an isopolyacid anion (M m’ O n’ ) c- Even if the heteropoly acid anion (X l’ M m’ O n’ ) c- In the above ionic formula, M is a polyatom, X is a heteroatom, m' is the composition ratio of polyatoms, n' is the composition ratio of oxygen atoms, and l' is the composition ratio of heteroatoms. Examples of polyatoms M include Mo, W, Ti, and Nb. Examples of heteroatoms X include Si, P, As, S, Fe, and Co. In addition, Na may be used as a part of the polyatoms. + and H + Among them, a polyoxoanion containing at least one of tungsten (W) and molybdenum (Mo) is preferred in terms of excellent heat resistance.

[0149] Examples of polyacid anions containing at least one of tungsten (W) and molybdenum (Mo) include tungstate ions [W 10 O 32 ] 4- , molybdate ion [MoO 19 ] 2- and heteropolyacid, phosphotungstate ion [PW 12 O 40 ] 3- , [P2W 18 O 62 ] 6- , silicotungstate ion [SiW 12 O 40 ] 4- , phosphomolybdate ion [PMo 12 O 40 ] 3- , silicomolybdate ion [SiMo 12 O 40 ] 4- , phosphotungstomolybdate ion [PW 12-x Mo x O 40 ] 3- (x is an integer between 1 and 11), [P2W 18-y Mo y O62 ] 6- (y is an integer from 1 to 17), silicotungstomolybdate ion [SiW 12-x Mo x O 40 ] 4- (x is an integer of 1 to 11). Among the above polyacid anions containing at least one of tungsten (W) and molybdenum (Mo), heteropolyacid anions are preferred, and heteropolyacid anions containing phosphorus (P) are more preferred, from the viewpoints of heat resistance and ease of raw material availability.

[0150] Furthermore, phosphotungstomolybdate ions [PW 10 Mo2O 40 ] 3- , [PW 11 Mo1O 40 ] 3- , phosphotungstate ion [PW 12 O 40 ] 3- From the viewpoint of heat resistance, it is more preferable that the material is one of the above.

[0151] The (A) metal compound may be used alone or in combination of two or more kinds.

[0152] The (A) metal compound may contain one or more (a) organic acids.

[0153] The metal compound (A) may be a hydrolysis product of a metal compound containing a hydrolyzable group, a hydrolysis-condensation product of a metal compound containing a hydrolyzable group, or a combination thereof. Here, the term "hydrolysis-condensation reaction" refers to a reaction in which a hydrolyzable group of a metal compound is hydrolyzed to convert it to -OH, and the two resulting -OH groups undergo dehydration-condensation to form -O-.

[0154] Alternatively, it is also possible to use compounds obtained by reacting these compounds with a substance that can become a monodentate ligand or a polydentate ligand through a ligand exchange reaction, and it is also possible to use a hydrolysis condensation reaction product of a metal-containing compound having a hydrolyzable group, or a compound obtained by reacting a hydrolysis condensation reaction product of a metal-containing compound having a hydrolyzable group with a substance that can become a monodentate ligand or a polydentate ligand.

[0155] <(B) Solvent> In the present invention, the solvent (B) that can be used in the metal-containing film-forming composition is not particularly limited as long as it dissolves or disperses the metal compound (A) and other additives contained therein.

[0156] Specifically, the organic solvents described in paragraphs

[0091] and

[0092] of JP 2007-199653 A can be added. More specifically, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, 2-heptanone, cyclopentanone, cyclohexanone, and γ-butyrolactone, or a mixture containing one or more of these, are preferably used.

[0157] Examples of other solvents that can be used include butanediol monomethyl ether, ethylene glycol monomethyl ether, butanediol monoethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, butanediol monopropyl ether, propylene glycol monopropyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, 1-butanol, 2-butanol, 2-methyl Examples of the solvent include methyl-1-propanol, 4-methyl-2-pentanol, acetone, tetrahydrofuran, toluene, hexane, ethyl acetate, cyclohexanone, methyl amyl ketone, propylene glycol dimethyl ether, diethylene glycol dimethyl ether, diamyl ether, isoamyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, t-butyl acetate, t-butyl propionate, propylene glycol mono t-butyl ether acetate, methyl isobutyl ketone, and cyclopentyl methyl ether.

[0158] The blending amount of (B) solvent is preferably 200 to 10,000 parts by mass, more preferably 250 to 5,000 parts by mass, per 100 parts by mass of (A) metal compound.

[0159] <(B1) High-boiling point solvent> In the metal-containing film-forming composition, the (B) solvent may include (B1) a high-boiling organic solvent.

[0160] (B1) The high-boiling organic solvent can be one or more organic solvents having a boiling point of 180° C. or higher.

[0161] For example, the (B) solvent may be a mixture of one or more organic solvents having a boiling point of less than 180° C. and one or more organic solvents having a boiling point of 180° C. or higher ((B1) high boiling point solvent).

[0162] The (B1) high-boiling point solvent is not particularly limited as long as it can dissolve or disperse each component of the metal-containing film-forming composition, and may be any of hydrocarbons, alcohols, ketones, esters, ethers, chlorinated solvents, etc., but specific examples include 1-octanol, 2-ethylhexanol, 1-nonanol, 1-decanol, 1-undecanol, ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4-heptanediol, 2-ethyl-1,3-Hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, glycerin, n-nonyl acetate, monohexyl ether, ethylene glycol mono-2-ethylhexyl ether, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, diethylene glycol monoethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol monoisobutyl ether, diethylene glycol monohexyl ether, diethylene glycol monophenyl ether, diethylene glycol monobenzyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol butyl methyl ether, triethylene glycol dimethyl ether, triethylene glycol monomethyl ether, triethylene glycol-n-butyl ether, triethylene glycol butyl methyl ether, tetraethylene glycol dimethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-n-butyl ether, tripropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, tripropylene glycol mono-n-propyl ether, tripropylene glycol mono-n-butyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, triacetin, propylene glycol diacetate, dipropylene glycol methyl-n-propyl ether, dipropylene glycol methyl ether acetate, 1,4-butanediol diacetate, 1,3-butylene glycol diacetate, 1,Examples of the diester include 6-hexanediol diacetate, triethylene glycol diacetate, γ-butyrolactone, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, dihexyl malonate, diethyl succinate, dipropyl succinate, dibutyl succinate, dihexyl succinate, dimethyl adipate, diethyl adipate, and dibutyl adipate, and these may be used alone or in combination.

[0163] The (B1) high-boiling-point solvent may be appropriately selected from, for example, those listed above, depending on the temperature at which the metal-containing film-forming composition is heat-treated. The (B1) high-boiling-point solvent preferably has a boiling point of 180°C to 300°C, more preferably 200°C to 300°C. Such a boiling point prevents excessive evaporation during baking (heat treatment), thereby suppressing the occurrence of defects due to drying during film formation. Furthermore, such a boiling point prevents evaporation after baking and does not remain in the film, thereby not adversely affecting film properties such as etching resistance.

[0164] When a (B1) high-boiling point solvent is used, the blending amount is preferably 1 to 30 parts by mass per 100 parts by mass of an organic solvent having a boiling point of less than 180° C. This blending amount is preferable because it can impart sufficient thermal fluidity during baking and does not remain in the film, preventing deterioration of film properties such as etching resistance.

[0165] <Other additives> The metal-containing film-forming composition may contain at least one selected from (C) a crosslinking agent, (D) an acid generator, and (E) a surfactant, as needed.

[0166] Hereinafter, components that may be contained in the metal-containing film-forming composition other than the (A) metal compound and (B) solvent will be described.

[0167] [(C) Crosslinking agent] A (C) crosslinking agent can also be added to the metal-containing film-forming composition to enhance curability and further suppress intermixing with the resist upper layer film. The (C) crosslinking agent is not particularly limited, and a wide variety of known crosslinking agents can be used. Examples include melamine-based crosslinking agents, glycoluril-based crosslinking agents, benzoguanamine-based crosslinking agents, urea-based crosslinking agents, β-hydroxyalkylamide-based crosslinking agents, isocyanurate-based crosslinking agents, aziridine-based crosslinking agents, oxazoline-based crosslinking agents, epoxy-based crosslinking agents, and phenol-based crosslinking agents. The (C) crosslinking agent can be used alone or in combination of two or more. When a (C) crosslinking agent is added, the amount added is preferably 5 to 50 parts by mass, more preferably 10 to 40 parts by mass, per 100 parts by mass of the (A) metal compound. Addition of 5 parts by mass or more ensures sufficient curability and suppresses intermixing with the resist upper layer film. On the other hand, if the amount added is 50 parts by mass or less, the proportion of the (A) metal compound in the composition will not decrease, and therefore the dry etching resistance will not deteriorate.

[0168] Specific examples of the melamine-based crosslinking agent include hexamethoxymethylated melamine, hexabutoxymethylated melamine, alkoxy- and / or hydroxy-substituted products thereof, and partial self-condensates thereof.

[0169] Specific examples of glycoluril crosslinking agents include tetramethoxymethylated glycoluril, tetrabutoxymethylated glycoluril, alkoxy and / or hydroxy substituted products thereof, and partial self-condensates thereof.

[0170] Specific examples of benzoguanamine-based crosslinking agents include tetramethoxymethylated benzoguanamine, tetrabutoxymethylated benzoguanamine, alkoxy- and / or hydroxy-substituted products thereof, and partial self-condensates thereof.

[0171] Specific examples of urea-based crosslinking agents include dimethoxymethylated dimethoxyethylene urea, its alkoxy and / or hydroxy substituted derivatives, and partial self-condensates thereof.

[0172] A specific example of the β-hydroxyalkylamide crosslinking agent is N,N,N',N'-tetra(2-hydroxyethyl)adipamide.

[0173] Specific examples of the isocyanurate crosslinking agent include triglycidyl isocyanurate and triallyl isocyanurate.

[0174] Specific examples of the aziridine crosslinking agent include 4,4'-bis(ethyleneiminocarbonylamino)diphenylmethane and 2,2-bishydroxymethylbutanol-tris[3-(1-aziridinyl)propionate].

[0175] Specific examples of the oxazoline-based crosslinking agent include 2,2'-isopropylidenebis(4-benzyl-2-oxazoline), 2,2'-isopropylidenebis(4-phenyl-2-oxazoline), 2,2'-methylenebis(4,5-diphenyl-2-oxazoline), 2,2'-methylenebis(4-phenyl-2-oxazoline), 2,2'-methylenebis(4-tert-butyl-2-oxazoline), 2,2'-bis(2-oxazoline), 1,3-phenylenebis(2-oxazoline), 1,4-phenylenebis(2-oxazoline), and 2-isopropenyloxazoline copolymer.

[0176] Specific examples of epoxy-based crosslinking agents include diglycidyl ether, ethylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,4-cyclohexanedimethanol diglycidyl ether, poly(glycidyl methacrylate), trimethylolethane triglycidyl ether, trimethylolpropane triglycidyl ether, and pentaerythritol tetraglycidyl ether.

[0177] Specific examples of phenol-based crosslinking agents include compounds represented by the following general formula (10). [ka] In the general formula (10), Q is a single bond or a q group having 1 to 20 carbon atoms. 1 R is a 2-valent hydrocarbon group. 16 is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. 1 is an integer between 1 and 5.)

[0178] In the general formula (10), Q is a single bond or a q group having 1 to 20 carbon atoms. 1 q is a valent hydrocarbon group. 1 is an integer of 1 to 5, preferably 2 or 3. Specific examples of Q include methane, ethane, propane, butane, isobutane, pentane, cyclopentane, hexane, cyclohexane, methylpentane, methylcyclohexane, dimethylcyclohexane, trimethylcyclohexane, benzene, toluene, xylene, ethylbenzene, ethylisopropylbenzene, diisopropylbenzene, methylnaphthalene, ethylnaphthalene, and eicosane. 16 is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. Specific examples of the alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, an isopentyl group, a hexyl group, an octyl group, an ethylhexyl group, a decyl group, and an eicosanyl group, and a hydrogen atom or a methyl group is preferred.

[0179] Specific examples of the compound represented by the general formula (10) include the following compounds: Among these, hexamethoxymethylated products of triphenolmethane, triphenolethane, 1,1,1-tris(4-hydroxyphenyl)ethane, and tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene are preferred from the viewpoint of improving the curability and thickness uniformity of the metal-containing film.

[0180] [ka]

[0181] [ka] (In the formula, R 16 is the same as above.)

[0182] <(D) Acid Generator> To further accelerate the curing reaction of the metal compound (A), an acid generator (D) can be added to the metal-containing film-forming composition. The acid generator (D) can be one that generates an acid by thermal decomposition or one that generates an acid by light irradiation, and either can be added. Specifically, the materials described in paragraphs

[0061] to

[0085] of JP 2007-199653 A can be added, but are not limited to these.

[0183] The acid generator (D) can be used alone or in combination of two or more. When the acid generator (D) is added, the amount of the acid generator (D) added is preferably 0.05 to 50 parts by mass, more preferably 0.1 to 10 parts by mass, per 100 parts by mass of the metal compound (A).

[0184] <(E) Surfactant> A (E) surfactant can be added to the metal-containing film-forming composition to improve the coating properties during spin coating. Examples of (E) surfactants that can be used include those described in paragraphs

[0142] to

[0147] of JP-A No. 2009-269953. When (E) surfactant is added, the amount added is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, per 100 parts by mass of the (A) metal compound.

[0185] The number of the metal-containing low refractive index films contained in the multilayer reflective film layer is preferably one or more, more preferably two or more, even more preferably three or more, and particularly preferably five or more.

[0186] Such a multilayer reflective film layer can increase the refractive index for EUV light, thus further improving the sensitivity of the resist upper layer film.

[0187] Depending on the number of low refractive index film layers in the multilayer reflective film layer, the number of high refractive index film layers in the pair also increases. From the perspective of etching process, the relationship between the number of low refractive index film layers s and the number of high refractive index film layers m included in the multilayer reflective film layer is preferably s = m or s < m.

[0188] As the low refractive index film, it is preferable to use one with a refractive index n at the wavelength of the EUV light being 0.97 or less, more preferably 0.965 or less, and even more preferably 0.96 or less.

[0189] Such a multilayer reflective film layer including a low refractive index film with such a refractive index has a high reflectivity for EUV light, thus further improving the sensitivity of the resist upper layer film.

[0190] As the low refractive index film, it is preferable to use one with a film thickness of 10 nm or less for one layer, more preferably 8 nm or less, even more preferably 6 nm or less, and particularly preferably 5 nm or less. As the lower limit value of the film thickness, it is preferably 1 nm or more, more preferably 2 nm or more, and even more preferably 3 nm or more.

[0191] By setting the film thickness of the low refractive index film within the above range, the reflectivity for EUV light can be further increased.

[0192] The film thicknesses of the low refractive index film and the high refractive index film in the multilayer reflective film layer may be the same or different for each layer. In order to improve the reflectivity, it is preferable that the film thicknesses of each layer of the low refractive index film are the same.

[0193] It is preferable that at least one adhesion film selected from a silicon-containing hard mask film made of a material containing Si and one or more elements selected from nitrogen, carbon, hydrogen, and oxygen, and a carbon-containing hard mask film made of a material containing carbon and one or more elements selected from nitrogen, hydrogen, and oxygen is included between the resist top layer film and the multilayer reflective film layer.

[0194] By including the adhesive film between the resist top layer and the multilayer reflective film, pattern collapse of the resist can be suppressed, which is preferable.

[0195] The adhesive film preferably has a composition of either a silicon-containing hard mask film made of a material containing Si and one or more elements selected from nitrogen, carbon, hydrogen, and oxygen, or a carbon-containing hard mask film made of a material containing carbon and one or more elements selected from nitrogen, hydrogen, and oxygen.

[0196] The thickness of the adhesive film is preferably 15 nm or less, more preferably 10 nm or less, even more preferably 8 nm or less, and particularly preferably 5 nm or less.

[0197] It is preferable to include a step of transferring the pattern to the processing layer on the substrate by dry etching using the resist upper layer film on which the pattern has been formed as a mask.

[0198] The layer to be processed is preferably provided immediately above with a high refractive index film made of a material containing carbon and one or more elements selected from nitrogen, hydrogen, and oxygen.

[0199] The high refractive index film containing carbon is preferably a material containing carbon and one or more elements selected from nitrogen, hydrogen, and oxygen, and the carbon content in the high refractive index film is preferably 60 mass % or more, more preferably 70 mass % or more, even more preferably 80 mass % or more, and particularly preferably 85 mass % or more.

[0200] By using such a high refractive index film directly on the workpiece layer, the resist pattern can be transferred to the workpiece layer with high precision. As explained above, a high refractive index film containing carbon and one or more elements selected from nitrogen, hydrogen, and oxygen can be formed by a method such as spin coating, PVD, CVD, or ALD.

[0201] An example of the pattern formation method of the present invention will be described with reference to FIG. 1. In the present invention, as a pattern formation method using a multilayer reflective film layer, as shown in FIG. 1(A), a high-refractive index film 3 is formed on a processable layer 2 on a substrate 1, a low-refractive index film 4 having a different refractive index n at the wavelength of EUV light than the high-refractive index film 3 is formed on the high-refractive index film 3, and a high-refractive index film 3 having a different refractive index n at the wavelength of EUV light than the low-refractive index film 4 is formed on the low-refractive index film 4, thereby forming a multilayer reflective film 100. Next, a resist upper layer film 6 is formed on the multilayer reflective film 100, and preferably an adhesion film 5 is formed to improve the effect of suppressing collapse of the resist film pattern. Subsequently, as shown in FIG. 1(B), an exposed portion 7 of the resist upper layer film is pattern-exposed. Next, as shown in FIG. 1(C), development is performed with a developer to form a resist upper layer film pattern 6a in the resist upper layer film.

[0202] Next, as shown in FIG. 1(D), the pattern is transferred to the adhesive film by dry etching using the patterned resist top layer film as a mask, forming an adhesive film pattern 5a. Next, as shown in FIG. 1(E), the pattern is transferred to the high-refractive-index film by dry etching using the patterned adhesive film as a mask, forming a high-refractive-index film pattern 3a. Next, as shown in FIG. 1(F), the pattern is transferred to the low-refractive-index film by dry etching using the patterned high-refractive-index film as a mask, forming a low-refractive-index film pattern 4a. Next, as shown in FIG. 1(G), the pattern is transferred to the high-refractive-index film by dry etching using the patterned low-refractive-index film as a mask, forming a high-refractive-index film pattern 3a. Next, as shown in FIG. 1(H), the processable layer 2 is processed by dry etching using the patterned high-refractive-index film as a mask, forming a processable layer pattern 2a.

[0203] When the high refractive index film is made of a material containing Si and one or more elements selected from nitrogen, carbon, hydrogen, and oxygen, it is preferable that the dry etching of the high refractive index film is performed using an etching gas mainly containing a fluorine-based gas.

[0204] When the high-refractive-index film is made of a material containing carbon and one or more elements selected from nitrogen, hydrogen, and oxygen, it is preferable that the dry etching of the high-refractive-index film be performed using an etching gas mainly containing an oxygen-based gas.

[0205] The dry etching of the low refractive index film is preferably carried out using an etching gas mainly containing a chlorine-based or bromine-based gas.

[0206] When the adhesion film is a silicon-containing hard mask film made of a material containing Si and one or more elements selected from nitrogen, carbon, hydrogen, and oxygen, the dry etching of the adhesion film is preferably performed using an etching gas mainly containing a fluorine-based gas.

[0207] When the adhesion film is a carbon-containing hard mask film made of a material containing carbon and one or more elements selected from nitrogen, hydrogen, and oxygen, the dry etching of the adhesion film is preferably performed using an etching gas mainly containing an oxygen-based gas.

[0208] The processing of the processing target layer is preferably carried out using an etching gas mainly containing a fluorine-based gas.

[0209] Specific examples of multilayer structures including a multilayer reflective film layer that can be used in the pattern formation method of the present invention include structures (A-1) to (A-4) in Figure 2, but the present invention is not limited to these. [Example]

[0210] EXAMPLES The present invention will be specifically explained below using examples and comparative examples, but the present invention is not limited to these.

[0211] [Pattern Formation Method and Reflectance Calculation (Examples 1-1 to 1-6, Comparative Example 1-1)] <Pattern formation method 1 (structure of Figure 2(A-1))> On an SiO2 substrate 1 having a processable layer 2, (1) ODL-301 manufactured by Shin-Etsu Chemical Co., Ltd. is applied by spin coating, and the substrate is heated at 350°C for 60 seconds. The substrate is then further heated at 500°C for 60 seconds in a nitrogen atmosphere (oxygen concentration 0.01%) to form a high refractive index film 3 having a film thickness of 35 nm. (2) A 4 nm thick Mo film (low refractive index film 4) is formed thereon by sputtering. (3) ODL-301 is applied thereon by spin coating, and the substrate is heated at 350°C for 60 seconds. The substrate is then further heated at 500°C for 60 seconds in a nitrogen atmosphere (oxygen concentration 0.01%) to form a high refractive index film 3 with a film thickness of 14 nm. (4) A silicon-containing resist intermediate film material (SOG-1) was applied onto the resist by spin coating and then heat-treated at 220°C for 60 seconds to form a silicon-containing resist intermediate film (adhesion film 5) with a thickness of 5 nm.

[0212] The silicon-containing resist interlayer material (SOG-1) was prepared by dissolving a silicon-containing interlayer polymer (SiP1) and a crosslinking catalyst (CAT1) in an organic solvent containing 0.1 mass% FC-4430 (manufactured by Sumitomo 3M) in the proportions shown in Table 1, and filtering the solution through a fluororesin filter with a pore size of 0.1 μm.

[0213] [Table 1]

[0214] The structural formulae of the silicon-containing interlayer polymer (SiP1) and crosslinking catalyst (CAT1) used are shown below. [ka]

[0215] <Pattern formation method 2 (structure of Figure 2(A-2))> On an SiO2 substrate 1 having a processable layer 2, (1) ODL-301 manufactured by Shin-Etsu Chemical Co., Ltd. is applied by spin coating, and the substrate is heated at 350°C for 60 seconds. The substrate is then further heated at 500°C for 60 seconds in a nitrogen atmosphere (oxygen concentration 0.01%) to form a high refractive index film 3 having a film thickness of 35 nm. (2) A 4 nm thick Mo film (low refractive index film 4) is formed thereon by sputtering. (3) ODL-301 is applied thereon by spin coating, and the substrate is heated at 350°C for 60 seconds. The substrate is then further heated at 500°C for 60 seconds in a nitrogen atmosphere (oxygen concentration 0.01%) to form a high refractive index film 3 with a film thickness of 10 nm. (4) A 4 nm thick Mo film (low refractive index film 4) is formed thereon by sputtering. (5) A silicon-containing resist intermediate film material (SOG-1) was applied onto the resist by spin coating and then heat-treated at 220°C for 60 seconds to form a silicon-containing resist intermediate film (adhesion film 5) with a thickness of 5 nm.

[0216] <Pattern formation method 3 (structure of Figure 2(A-3))> On an SiO2 substrate 1 having a processable layer 2, (1) ODL-301 manufactured by Shin-Etsu Chemical Co., Ltd. is applied by spin coating, and the substrate is heated at 350°C for 60 seconds. The substrate is then further heated at 500°C for 60 seconds in a nitrogen atmosphere (oxygen concentration 0.01%) to form a high refractive index film 3 having a film thickness of 35 nm. (2) A bismuth-containing material (BiO-1) is applied thereon by spin coating, and then heat-treated at 450°C for 60 seconds to form a low refractive index film 4 with a thickness of 5 nm. (3) ODL-301 is applied thereon by spin coating, and the substrate is heated at 350°C for 60 seconds. The substrate is then further heated at 500°C for 60 seconds in a nitrogen atmosphere (oxygen concentration 0.01%) to form a high refractive index film 3 with a film thickness of 15 nm. (4) A bismuth-containing material (BiO-1) is applied thereon by spin coating, and then heat-treated at 450°C for 60 seconds to form a low refractive index film 4 with a thickness of 5 nm. (5) ODL-301 is applied thereon by spin coating, and the substrate is heated at 350°C for 60 seconds. The substrate is then further heated at 500°C for 60 seconds in a nitrogen atmosphere (oxygen concentration 0.01%) to form a high refractive index film 3 having a film thickness of 15 nm. (6) A silicon-containing resist intermediate film material (SOG-1) was applied onto the resist by spin coating and then heat-treated at 220°C for 60 seconds to form a silicon-containing resist intermediate film (adhesion film 5) with a thickness of 5 nm.

[0217] The bismuth-containing material (BiO-1) was prepared by dissolving bismuth (III) 2-ethylhexanoate in an organic solvent in the proportions shown in Table 2 and filtering the solution through a fluororesin filter with a pore size of 0.1 μm.

[0218] [Table 2]

[0219] <Pattern formation method 4 (structure of Figure 2(A-4))> On an SiO2 substrate 1 having a processable layer 2, (1) ODL-301 manufactured by Shin-Etsu Chemical Co., Ltd. is applied by spin coating, and the substrate is heated at 350°C for 60 seconds. The substrate is then further heated at 500°C for 60 seconds in a nitrogen atmosphere (oxygen concentration 0.01%) to form a high refractive index film 3 having a film thickness of 35 nm. (2) A bismuth-containing material (BiO-1) is applied thereon by spin coating, and then heat-treated at 450°C for 60 seconds to form a low refractive index film 4 with a thickness of 4 nm. (3) ODL-301 is applied thereon by spin coating, and the substrate is heated at 350°C for 60 seconds. The substrate is then further heated at 500°C for 60 seconds in a nitrogen atmosphere (oxygen concentration 0.01%) to form a high refractive index film 3 with a film thickness of 10 nm. (4) A bismuth-containing material (BiO-1) is applied thereon by spin coating, and then heat-treated at 450°C for 60 seconds to form a low refractive index film 4 with a thickness of 4 nm. (5) ODL-301 is applied thereon by spin coating, and the substrate is heated at 350°C for 60 seconds. The substrate is then further heated at 500°C for 60 seconds in a nitrogen atmosphere (oxygen concentration 0.01%) to form a high refractive index film 3 having a thickness of 10 nm. (6) A bismuth-containing material (BiO-1) is applied thereon by spin coating, and then heat-treated at 450°C for 60 seconds to form a low refractive index film 4 with a thickness of 4 nm. (7) ODL-301 is applied thereon by spin coating, and the substrate is heated at 350°C for 60 seconds. The substrate is then further heated at 500°C for 60 seconds in a nitrogen atmosphere (oxygen concentration 0.01%) to form a high refractive index film 3 having a film thickness of 10 nm. (8) A bismuth-containing material (BiO-1) is applied thereon by spin coating, and then heat-treated at 450°C for 60 seconds to form a low refractive index film 4 with a thickness of 4 nm. (9) ODL-301 is applied thereon by spin coating, and the substrate is heated at 350°C for 60 seconds. The substrate is then further heated at 500°C for 60 seconds in a nitrogen atmosphere (oxygen concentration 0.01%) to form a high refractive index film 3 having a film thickness of 10 nm. (10) A bismuth-containing material (BiO-1) is applied thereon by spin coating, and then heat-treated at 450°C for 60 seconds to form a low refractive index film 4 with a thickness of 4 nm. (11) A silicon-containing resist intermediate film material (SOG-1) was applied onto the resist by spin coating and then heat-treated at 220°C for 60 seconds to form a silicon-containing resist intermediate film (adhesion film 5) with a thickness of 5 nm.

[0220] <Pattern formation method 5 (structure of Figure 2(A-4))> On an SiO2 substrate 1 having a processable layer 2, (1) ODL-301 manufactured by Shin-Etsu Chemical Co., Ltd. is applied by spin coating, and the substrate is heated at 350°C for 60 seconds. The substrate is then further heated at 500°C for 60 seconds in a nitrogen atmosphere (oxygen concentration 0.01%) to form a high refractive index film 3 having a film thickness of 35 nm. (2) A hafnium-containing material (HfO-1) is applied thereon by spin coating, and then heat-treated at 450°C for 60 seconds to form a low refractive index film 4 with a thickness of 4 nm; (3) ODL-301 is applied thereon by spin coating, and the substrate is heated at 350°C for 60 seconds. The substrate is then further heated at 500°C for 60 seconds in a nitrogen atmosphere (oxygen concentration 0.01%) to form a high refractive index film 3 with a film thickness of 10 nm. (4) A hafnium-containing material (HfO-1) is applied thereon by spin coating, and then heat-treated at 450°C for 60 seconds to form a low refractive index film 4 with a thickness of 4 nm. (5) ODL-301 is applied thereon by spin coating, and the substrate is heated at 350°C for 60 seconds. The substrate is then further heated at 500°C for 60 seconds in a nitrogen atmosphere (oxygen concentration 0.01%) to form a high refractive index film 3 having a thickness of 10 nm. (6) A hafnium-containing material (HfO-1) is applied thereon by spin coating, and then heat-treated at 450°C for 60 seconds to form a low refractive index film 4 with a thickness of 4 nm; (7) ODL-301 is applied thereon by spin coating, and the substrate is heated at 350°C for 60 seconds. The substrate is then further heated at 500°C for 60 seconds in a nitrogen atmosphere (oxygen concentration 0.01%) to form a high refractive index film 3 having a film thickness of 10 nm. (8) A hafnium-containing material (HfO-1) is applied thereon by spin coating, and then heat-treated at 450°C for 60 seconds to form a low refractive index film 4 with a film thickness of 4 nm. (9) ODL-301 is applied thereon by spin coating, and the substrate is heated at 350°C for 60 seconds. The substrate is then further heated at 500°C for 60 seconds in a nitrogen atmosphere (oxygen concentration 0.01%) to form a high refractive index film 3 having a film thickness of 10 nm. (10) A hafnium-containing material (HfO-1) is applied thereon by spin coating, and then heat-treated at 450°C for 60 seconds to form a low refractive index film 4 having a thickness of 4 nm; (11) A silicon-containing resist intermediate film material (SOG-1) was applied onto the resist by spin coating and then heat-treated at 220°C for 60 seconds to form a silicon-containing resist intermediate film (adhesion film 5) with a thickness of 5 nm.

[0221] The hafnium-containing material (HfO-1) was prepared by dissolving the hafnium-containing polymer (HfP1) synthesized below in an organic solvent in the proportions shown in Table 3 and filtering the solution through a fluororesin filter with a pore size of 0.1 μm.

[0222] (Synthesis of hafnium-containing polymer (HfP1)) Under a nitrogen atmosphere, a solution of 54.4 g of hafnium(IV) n-butoxide in 40.5 g of n-butanol was added dropwise over 2 hours at room temperature while stirring. 17.4 g of allyl acetoacetate was added to the resulting solution and stirred at room temperature for 30 minutes. The solution was concentrated under reduced pressure at 30°C and then heated to 60°C and continued to be heated under reduced pressure until no more distillate was produced. When no more distillate was observed, 69.0 g of a PGMEA / PGME (70 / 30 mass ratio) solution was added and heated at 40°C under reduced pressure until no more IPA was produced, yielding a PGMEA / PGME solution of the hafnium-containing polymer (HfP1). The concentration of components other than the solvent in the solution was 16% by mass.

[0223] [Table 3]

[0224] <Pattern formation method 6 (structure of Figure 2(A-4))> On an SiO2 substrate 1 having a processable layer 2, (1) ODL-301 manufactured by Shin-Etsu Chemical Co., Ltd. is applied by spin coating, and the substrate is heated at 350°C for 60 seconds. The substrate is then further heated at 500°C for 60 seconds in a nitrogen atmosphere (oxygen concentration 0.01%) to form a high refractive index film 3 having a film thickness of 35 nm. (2) A molybdenum-containing material (MoO-1) is applied thereon by spin coating, and then heat-treated at 450°C for 60 seconds to form a low refractive index film 4 with a thickness of 4 nm. (3) ODL-301 is applied thereon by spin coating, and the substrate is heated at 350°C for 60 seconds. The substrate is then further heated at 500°C for 60 seconds in a nitrogen atmosphere (oxygen concentration 0.01%) to form a high refractive index film 3 with a film thickness of 10 nm. (4) A molybdenum-containing material (MoO-1) is applied thereon by spin coating, and then heat-treated at 450°C for 60 seconds to form a low refractive index film 4 with a thickness of 4 nm. (5) ODL-301 is applied thereon by spin coating, and the substrate is heated at 350°C for 60 seconds. The substrate is then further heated at 500°C for 60 seconds in a nitrogen atmosphere (oxygen concentration 0.01%) to form a high refractive index film 3 having a thickness of 10 nm. (6) A molybdenum-containing material (MoO-1) is applied thereon by spin coating, and then heat-treated at 450°C for 60 seconds to form a low refractive index film 4 with a thickness of 4 nm. (7) ODL-301 is applied thereon by spin coating, and the substrate is heated at 350°C for 60 seconds. The substrate is then further heated at 500°C for 60 seconds in a nitrogen atmosphere (oxygen concentration 0.01%) to form a high refractive index film 3 having a film thickness of 10 nm. (8) A molybdenum-containing material (MoO-1) is applied thereon by spin coating, and then heat-treated at 450°C for 60 seconds to form a low refractive index film 4 with a thickness of 4 nm. (9) ODL-301 is applied thereon by spin coating, and the substrate is heated at 350°C for 60 seconds. The substrate is then further heated at 500°C for 60 seconds in a nitrogen atmosphere (oxygen concentration 0.01%) to form a high refractive index film 3 having a film thickness of 10 nm. (10) A molybdenum-containing material (MoO-1) is applied thereon by spin coating, and then heat-treated at 450°C for 60 seconds to form a low refractive index film 4 having a thickness of 4 nm. (11) A silicon-containing resist intermediate film material (SOG-1) was applied onto the resist by spin coating and then heat-treated at 220°C for 60 seconds to form a silicon-containing resist intermediate film (adhesion film 5) with a thickness of 5 nm.

[0225] The molybdenum-containing material (MoO-1) was prepared by dissolving bis(acetylacetonato)dioxomolybdenum(VI) in an organic solvent in the proportions shown in Table 4 and filtering the solution through a fluororesin filter with a pore size of 0.1 μm.

[0226] [Table 4]

[0227] <Comparative Pattern Forming Method 1 (Structure of FIG. 3(R-1))> On an SiO2 substrate 1 having a processable layer 2, (1) ODL-301 manufactured by Shin-Etsu Chemical Co., Ltd. is applied by spin coating, and the substrate is heated at 350°C for 60 seconds. The substrate is then further heated at 500°C for 60 seconds in a nitrogen atmosphere (oxygen concentration 0.01%) to form a high refractive index film 8 having a film thickness of 35 nm. (2) A silicon-containing resist intermediate film material (SOG-1) was applied onto the resist by spin coating and then heat-treated at 220°C for 60 seconds to form a silicon-containing resist intermediate film (adhesion film 9) with a thickness of 10 nm.

[0228] To calculate the refractive index n and extinction coefficient k for each film in EUV light, see the CXRO (The Center for X-ray Optics) website.<http: / / henke.lbl.gov / optical_constants / getdb2.html> The results are shown in Table 5.

[0229] [Table 5]

[0230] The photoresist material prepared according to the composition shown in Table 6 was applied to the adhesive film prepared above to form a 40 nm thick photoresist film. The photoresist film was then exposed to EUV light (NA 0.33, σ 0.8 / 0.5, hexapole illumination) and the reflectance of EUV light from the multilayer reflective film to the photoresist film was calculated. The reflectance was calculated using PROLITH 2020a (Litho Tech Japan Co., Ltd.). The results are shown in Table 7.

[0231] [Table 6]

[0232] The polymer, quencher, sensitizer, surfactant, and organic solvent used in the photoresist material are as follows.

[0233] [ka]

[0234] [ka]

[0235] Surfactant: 3M FC-4430 Organic solvent: PGMEA (propylene glycol monomethyl ether acetate) CyHO (cyclohexanone) PGME (Propylene Glycol Monomethyl Ether)

[0236] [Table 7]

[0237] As shown in Table 7, the pattern forming method of the present invention (Examples 1-1 to 1-6) was able to achieve high reflection of EUV light compared to the conventional tri-layer structure (Comparative Example 1-1). In particular, it was found that high reflectivity can be obtained by including two or more layers of metal-containing films that serve as low refractive index films in the multilayer reflective film (comparison between Example 1-1 and Example 1-2, and Example 1-3 and Example 1-4).

[0238] [EUV Lithography Evaluation (Examples 2-1 to 2-3, Comparative Example 2-1)] The photoresist material used in Example 1 was applied to the adhesion film prepared by the above pattern formation method to form a 40 nm thick photoresist film. The photoresist film was then exposed to EUV (NA 0.33, σ 0.8 / 0.5, hexapole illumination), subjected to PEB on a hot plate at 100°C for 60 seconds, and developed with a 2.38 mass% TMAH aqueous solution for 30 seconds to obtain a hole pattern with a dimension of 23 nm. Using a critical dimension SEM (CG5000) manufactured by Hitachi High-Technologies Corporation, the exposure dose when holes were formed with a dimension of 23 nm was measured and used as the sensitivity. The dimensions of 50 holes were also measured and the dimension variation (CDU, 3σ) was calculated. The results are shown in Table 8.

[0239] [Table 8]

[0240] As shown in Table 8, the pattern formation method of the present invention (Examples 2-1 to 2-3) was able to form patterns with high sensitivity without degradation of the CDU compared to the conventional tri-layer structure (Comparative Example 2-1). It is presumed that the sensitivity of the resist was improved by the reflection of EUV light from the multilayer reflective film layer to the photoresist film.

[0241] As described above, the present invention can provide a pattern formation method and a laminate that can break the trade-off between sensitivity and LWR and contribute to improving sensitivity while maintaining the LWR of the resist top layer film, and therefore is highly useful in the field of EUV lithography.

[0242] The present specification includes the following aspects. [1]: forming a resist top layer film on at least one surface of a substrate; irradiating the resist top layer film with EUV light; developing the resist top layer film to form a pattern; A pattern formation method using EUV lithography, comprising: a multilayer reflective film layer between the substrate and the resist top layer; A pattern forming method characterized in that the multilayer reflective film layer has a structure in which two or more types of materials with different refractive indices n at the wavelength of EUV light are alternately laminated. [2]: The pattern forming method of [1] above, characterized in that the multilayer reflective film layer includes a structure in which two or more materials having refractive indices n at the wavelength of EUV light that differ by 0.01 or more are alternately stacked. [3]: The pattern forming method of [1] or [2] above, characterized in that the multilayer reflective film layer has one or more high refractive index films made of a material containing Si and one or more elements selected from nitrogen, carbon, hydrogen, and oxygen, and one or more low refractive index films made of a material containing one or more metals selected from Ti, Cr, Ni, Zr, Nb, Mo, Ru, Rh, Hf, Ta, W, and Bi. [4]: The pattern forming method of [1] or [2] above, characterized in that the multilayer reflective film layer has one or more high refractive index films made of a material containing carbon and one or more elements selected from nitrogen, hydrogen, and oxygen, and one or more low refractive index films made of a material containing one or more metals selected from Ti, Cr, Ni, Zr, Nb, Mo, Ru, Rh, Hf, Ta, W, and Bi. [5]: The pattern forming method according to [1] or [2], characterized in that the multilayer reflective film layer includes two or more low refractive index films made of a material containing one or more metals selected from the group consisting of Ti, Cr, Ni, Zr, Nb, Mo, Ru, Rh, Hf, Ta, W, and Bi. [6]: The pattern forming method according to any one of [3] to [5], wherein the low refractive index film has a refractive index n of 0.97 or less at the wavelength of the EUV light. [7]: The pattern forming method according to any one of [3] to [6], wherein the low refractive index film has a thickness of 10 nm or less per layer. [8]: The pattern formation method according to any one of [1] to [7] above, characterized in that at least one adhesion film selected from a silicon-containing hard mask film made of a material containing Si and one or more elements selected from nitrogen, carbon, hydrogen, and oxygen, and a carbon-containing hard mask film made of a material containing carbon and one or more elements selected from nitrogen, hydrogen, and oxygen is included between the resist top layer film and the multilayer reflective film layer. [9]: A pattern forming method according to any one of [1] to [8], characterized in that it comprises a step of transferring the pattern to the processing layer on the substrate by dry etching using the resist top layer film on which the pattern has been formed as a mask.

[10] : A laminate comprising a substrate to be processed on which a pattern is to be formed, a multilayer reflective film layer on the substrate to be processed, and a resist top layer on the multilayer reflective film layer, wherein the multilayer reflective film layer is formed by alternately laminating two or more materials having different refractive indices n at the wavelength of EUV light.

[0243] The present invention is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits similar effects is included within the technical scope of the present invention. [Explanation of symbols]

[0244] 1...Substrate, 2...Layer to be processed, 2a...pattern (pattern formed on the processing layer), 3...high refractive index film, 3a...high refractive index film pattern, 4...low refractive index film, 4a...low refractive index film pattern, 5...adhesive film, 5a...adhesive film pattern, 6...resist upper layer film, 6a...resist upper layer film pattern, 7...exposed portion, 8...High refractive index film, 9...Adhesive film, 100...Multilayer reflective film.

Claims

1. forming a resist top layer film on at least one surface of the substrate; irradiating the resist top layer film with EUV light; developing the resist top layer film to form a pattern; A pattern formation method using EUV lithography, comprising: a multilayer reflective film layer between the substrate and the resist top layer; A pattern forming method characterized in that the multilayer reflective film layer has a structure in which two or more types of materials having different refractive indices n at the wavelength of EUV light are alternately laminated.

2. 2. The pattern formation method according to claim 1, wherein the multilayer reflective film layer includes a structure in which two or more materials having refractive indices n at the wavelength of the EUV light that differ by 0.01 or more are alternately stacked.

3. 2. The pattern formation method according to claim 1, wherein the multilayer reflective film layer comprises one or more high-refractive-index films made of a material containing Si and one or more elements selected from nitrogen, carbon, hydrogen, and oxygen, and one or more low-refractive-index films made of a material containing one or more metals selected from Ti, Cr, Ni, Zr, Nb, Mo, Ru, Rh, Hf, Ta, W, and Bi.

4. 2. The pattern formation method according to claim 1, wherein the multilayer reflective film layer comprises one or more high-refractive-index films made of a material containing carbon and one or more elements selected from nitrogen, hydrogen, and oxygen, and one or more low-refractive-index films made of a material containing one or more metals selected from Ti, Cr, Ni, Zr, Nb, Mo, Ru, Rh, Hf, Ta, W, and Bi.

5. 2. The pattern forming method according to claim 1, wherein the multilayer reflective film layer includes two or more low refractive index films made of a material containing one or more metals selected from the group consisting of Ti, Cr, Ni, Zr, Nb, Mo, Ru, Rh, Hf, Ta, W, and Bi.

6. 4. The pattern formation method according to claim 3, wherein the low refractive index film has a refractive index n of 0.97 or less at the wavelength of the EUV light.

7. 5. The pattern formation method according to claim 4, wherein the low refractive index film has a refractive index n of 0.97 or less at the wavelength of the EUV light.

8. 6. The pattern formation method according to claim 5, wherein the low refractive index film has a refractive index n of 0.97 or less at the wavelength of the EUV light.

9. 4. The pattern forming method according to claim 3, wherein the low refractive index film has a thickness of 10 nm or less per layer.

10. 5. The pattern forming method according to claim 4, wherein the low refractive index film has a thickness of 10 nm or less per layer.

11. 6. The pattern forming method according to claim 5, wherein the low refractive index film has a thickness of 10 nm or less per layer.

12. 2. The pattern formation method according to claim 1, further comprising at least one adhesion film selected from the group consisting of a silicon-containing hard mask film made of a material containing Si and one or more elements selected from nitrogen, carbon, hydrogen, and oxygen, and a carbon-containing hard mask film made of a material containing carbon and one or more elements selected from nitrogen, hydrogen, and oxygen, between the resist top layer film and the multilayer reflective film layer.

13. 13. The pattern forming method according to claim 1, further comprising a step of transferring the pattern to the workpiece layer on the substrate by dry etching using the resist top layer film on which the pattern has been formed as a mask.

14. A laminate comprising: a substrate to be processed on which a pattern is to be formed; a multilayer reflective film layer on the substrate to be processed; and a resist top layer film on the multilayer reflective film layer, wherein the multilayer reflective film layer is formed by alternately laminating two or more types of materials having different refractive indices n at the wavelength of EUV light.

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