Composition for forming metal oxide film, pattern forming method, and metal oxide film forming method

Abstract

The present invention relates to a composition for forming a metal oxide film, a pattern forming method, and a metal oxide film forming method. The present invention provides a composition for forming a metal oxide film, which has excellent dry etching resistance to known organic underlayer film materials, excellent filling characteristics to known metal hard masks, can reduce cracks accompanying thick film formation, and has excellent storage stability. A composition for forming a metal oxide film, comprising: metal oxide nanoparticles, a fluidity promoter containing a resin having a structural unit represented by the following general formula (1), a dispersion stabilizer composed of an aromatic-containing compound having two or more benzene rings, or one benzene ring and a structure represented by the following general formula (C-1) and having a molecular weight of 500 or less, an organic solvent, the content of the fluidity promoter relative to the whole composition is 9% by mass or more, Mw / Mn is 2.50 ≤ Mw / Mn ≤ 9.00, and does not contain a cardo structure.

Description

Technical Field

[0001] The present invention relates to a composition for forming a metal oxide film, a patterning method, and a method for forming a metal oxide film. Background Art

[0002] With the high integration and high speed of LSIs, the miniaturization of pattern sizes has advanced rapidly. In lithography technology, with this miniaturization, by shortening the wavelength of the light source and appropriately selecting the corresponding resist composition, the formation of fine patterns has been achieved. At the center of this is a positive photoresist composition used in a single layer. This single-layer positive photoresist composition has a skeleton in the resist resin that has etching resistance to dry etching using chlorine-based or fluorine-based gas plasmas and a switching mechanism that causes the exposed portion to dissolve. By this, the exposed portion is dissolved to form a pattern, and the remaining resist pattern is used as an etching mask to dry-etch the substrate to be processed.

[0003] However, if the film thickness of the photoresist film used is directly miniaturized, that is, if the pattern width is further reduced, the resolution performance of the photoresist film will decrease, and if the photoresist film is to be pattern-developed using a developer, the so-called aspect ratio will become too large, and as a result, there will be a problem of pattern collapse. Therefore, with the miniaturization of patterns, the photoresist film becomes thinner and thinner.

[0004] On the other hand, the processing of the substrate to be processed is usually a method of using the photoresist film with a formed pattern as an etching mask and dry-etching the substrate, but in reality, there is no dry-etching method that can achieve complete etching selectivity between the photoresist film and the substrate to be processed. Therefore, in substrate processing, there is a problem that even the photoresist film is damaged and collapses, and the resist pattern cannot be correctly transferred to the substrate to be processed. With the miniaturization of patterns, higher dry-etching resistance is required for the resist composition. However, on the other hand, in order to improve the resolution, the resin used in the photoresist composition increasingly requires a resin with low light absorption at the exposure wavelength. Therefore, as the exposure light progresses to shorter wavelengths such as i-ray, KrF, and ArF, the resin also changes to novolak resin, polyhydroxystyrene, and a resin with an aliphatic polycyclic skeleton. However, in reality, the etching rate under the dry-etching conditions during substrate processing becomes faster, and the latest photoresist compositions with high resolution tend to have weaker etching resistance instead.

[0005] Therefore, it is necessary to dry-etch the substrate to be processed with a thinner and weaker-etching-resistant photoresist film, and ensuring the materials and processes in this processing step has become an urgent matter.

[0006] As one of the methods for solving such problems, there is a multilayer resist method. In this method, an interlayer resist film (i.e., the upper resist film) with different etching selectivity from the upper resist film and the substrate to be processed is inserted between the upper resist film and the substrate to be processed. After obtaining a pattern on the upper resist film, the pattern of the upper resist film is used as a dry etching mask, and the pattern is transferred to the interlayer resist film by dry etching using the upper resist film pattern as a dry etching mask. Then, the interlayer resist film is used as a dry etching mask, and the pattern is transferred to the substrate to be processed by dry etching.

[0007] One of the multilayer resist methods is a three-layer resist method that can be implemented using a general resist composition used in a single-layer resist method. In this three-layer resist method, for example, an organic film obtained by forming a novolak resin or the like on the substrate to be processed is used as the lower resist film, a silicon-containing interlayer resist film is formed thereon as the interlayer resist film, and a normal organic photoresist film is formed thereon as the upper resist film. When dry etching is performed using a fluorine-based gas plasma, the organic upper resist film can achieve a good etching selectivity ratio with respect to the silicon-containing interlayer resist film. Therefore, the pattern of the upper resist film can be transferred to the silicon-containing interlayer resist film by dry etching using the fluorine-based gas plasma. According to this method, even if a resist composition that is difficult to form a pattern with a sufficient film thickness for directly processing the substrate or a resist composition that does not have sufficient dry etching resistance for substrate processing is used, if the pattern can be transferred to the silicon-containing interlayer resist film (interlayer resist film), and then the pattern is transferred by dry etching using an oxygen-based or hydrogen-based gas plasma, a pattern of an organic film (lower resist film) made of novolak resin or the like with sufficient dry etching resistance for substrate processing can be obtained. As described above, the lower resist film, for example, those described in Patent Document 1, are already known.

[0008] On the other hand, in recent years, the high stacking of 3D-NAND memories has accelerated, and the necessity of a thick film lower resist film material that can balance the filling characteristics of high aspect ratio patterns of a substrate without voids and excellent dry etching resistance for transferring fine structure patterns with high precision to the substrate to be processed has increased. There have been reports of thick film organic lower film materials with excellent filling characteristics, such as those described in Patent Document 2, etc. However, when expected to be used in an advanced era, there are concerns about dry etching resistance, and the applicable limit of known coating-type organic lower film materials has been approached.

[0009] In response to the problem of the dry etching resistance of the underlying film material of a coating-type organic resist, attention has been paid to the method of using a metal oxide film for the underlying resist film. However, with only a metal oxide material, the fluidity is insufficient, and it is difficult to fill a high aspect ratio pattern substrate. To improve the fluidity, a composition containing an organic material is preferably used. Regarding a composition in which an organic material is added to a metal oxide compound, reports have been made in Patent Document 3 and Patent Document 4. Although the filling characteristics are not mentioned, the metal oxide dicarboxylate used in Patent Document 3 and the hydrolysis condensate of the metal alkoxide used in Patent Document 4 have a large thermal shrinkage, which will induce a significant deterioration in the filling property, and there are concerns that it may not be perfect as a resist underlying film material that requires a high degree of filling characteristics.

[0010] In response to this, a composition for forming a metal oxide film in which a high-carbon polymer is added to metal oxide nanoparticles has been proposed (Patent Document 5). By using metal oxide nanoparticles with a small thermal shrinkage for the metal oxide compound, it is reported that the filling characteristics of the metal oxide compound can be improved. Also, a high-carbon polymer has been proposed as a fluidity promoter for metal oxide nanoparticles, but the above high-carbon polymer is insufficient in terms of thermal fluidity, and there are concerns that it may not be perfect in filling a high aspect ratio pattern substrate. Also, since the above high-carbon polymer has a high carbon content and a rigid structure, there are concerns that cracks may occur during thick film formation.

[0011] As an organic material having excellent dry etching resistance and thermal fluidity, materials having a cardo structure and a fluorene skeleton can be cited. There is a known resist underlying film material that combines a compound or polymer having a cardo structure as a thermal fluidity promoter with metal oxide nanoparticles. However, although the above materials have excellent dry etching resistance and filling characteristics, the above thermal fluidity promoter has a high carbon content and a rigid cardo structure, so cracks will occur during thick film formation. Also, for the filling sacrificial film for advanced 3D-NAND, the filling property of a high aspect ratio pattern substrate is insufficient. In addition, if the concentration of the composition is increased to a concentration capable of forming a thick film, there will be a situation where the nanoparticles aggregate and defects occur, resulting in unsatisfactory storage stability.

[0012] Prior Art Documents

[0013] Patent Documents

[0014] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-205685

[0015] [Patent Document 2] Japanese Patent No. 6550760

[0016] [Patent Document 3] Japanese Patent No. 6342998

[0017] [Patent Document 4] Japanese Patent Publication No. 5756134

[0018] [Patent Document 5] Japanese Patent Publication No. 7008075 Summary of the Invention

[0019] [Problems to be Solved by the Invention]

[0020] In view of the above circumstances, an object of the present invention is to provide a composition for forming a metal oxide film, a pattern forming method using this material, and a method for forming a metal oxide film (an underlayer film for a resist), which have excellent dry etching resistance to known organic underlayer film materials, excellent filling characteristics for known metal hard masks, can reduce cracks accompanying thick film formation, and have excellent storage stability.

[0021] [Means for Solving the Problems]

[0022] In order to solve the above problems, the present invention provides a composition for forming a metal oxide film, which is characterized by containing:

[0023] (A) Metal oxide nanoparticles,

[0024] (B) A fluidity promoter of a resin containing a structural unit represented by the following general formula (1),

[0025] (C) A dispersion stabilizer composed of an aromatic compound containing two or more benzene rings, or one benzene ring and a structure represented by the following general formula (C-1) and having a molecular weight of 500 or less in terms of molecular formula, and

[0026] (D) An organic solvent,

[0027] The content of the (B) fluidity promoter in the whole composition is 9% by mass or more, the ratio Mw / Mn of the weight average molecular weight Mw to the number average molecular weight Mn in terms of polystyrene measured by gel permeation chromatography is 2.50 ≤ Mw / Mn ≤ 9.00, and it does not contain compounds and polymers having a cardo structure,

[0028] [Chemical Formula 1]

[0029]

[0030] In the general formula (1), R a is a saturated monovalent organic group having 1 to 30 carbon atoms or an unsaturated monovalent organic group having 2 to 30 carbon atoms, X is a divalent organic group having 1 to 30 carbon atoms, p is an integer of 0 to 5, q 1 is an integer of 1 to 6, p + q 1 is an integer of 1 or more and 6 or less, q 2 is 0 or 1,

[0031] [Chemical formula 2]

[0032]

[0033] In the formula, * represents the bonding position, and W is an organic group having 1 to 4 carbon atoms.

[0034] If it is a composition for forming a metal oxide film, it can be used as a resist underlayer film material used in the multilayer resist method, and contains a fluidity promoter with excellent cracking resistance. Therefore, it can form a thick film to show excellent dry etching resistance from metal oxide nanoparticles. Also, due to the synergistic effect of the fluidity promoter and the dispersion stabilizer, it can exhibit excellent thermal fluidity, and can provide a resist underlayer film material that can fill a high aspect ratio pattern substrate without voids, which is difficult to achieve when only metal oxide nanoparticles are used. Furthermore, by using a dispersion stabilizer with a specific structure, a composition for forming a metal oxide film can be provided, in which even in a high-concentration solution with a resin content of 9% by mass or more, the nanoparticles can still maintain a good dispersion state and have excellent storage stability.

[0035] The aforementioned (B) fluidity promoter is preferably a fluidity promoter containing a resin having a structural unit represented by the aforementioned general formula (1) and further containing a resin having a structural unit represented by the following general formula (2), or a resin having both a structural unit represented by the aforementioned general formula (1) and a structural unit represented by the following general formula (2).

[0036] [Chemical formula 3]

[0037]

[0038] In the general formula (2), R a is a saturated monovalent organic group having 1 to 30 carbon atoms or an unsaturated monovalent organic group having 2 to 30 carbon atoms, R b is a saturated hydrocarbon group having 1 to 30 carbon atoms or an unsaturated hydrocarbon group having 2 to 10 carbon atoms, X is a divalent organic group having 1 to 30 carbon atoms, p is an integer from 0 to 5, q 1 is an integer from 1 to 6, p + q 1 is an integer of 1 or more and 6 or less, q 2 is 0 or 1.

[0039] If the aforementioned fluidity promoter contains a resin having a structural unit represented by the aforementioned general formula (2), or contains both a resin having a structural unit represented by the aforementioned general formula (1) and a structural unit represented by the aforementioned general formula (2), the fluidity increases, which is effective for filling a higher aspect ratio pattern substrate. Also, due to its low affinity for polar solvents, it is effective for reducing the amount of residual solvent in the filled film.

[0040] In the aforementioned general formula (2), it is preferable that R bIt is an alkyl group having 1 to 30 carbon atoms or any one of the structures represented by the following general formula (3). When the proportion of the general formula (1) is a and the proportion of the general formula (2) is b, the content of the general formula (2) satisfies the relationship of a + b = 1 and 0.2 ≤ b ≤ 0.8.

[0041] [Chemical formula 4]

[0042]

[0043] In the general formula (3), * represents the bonding site to the oxygen atom, and R A is a divalent organic group having 1 to 10 carbon atoms which may also be substituted, and R B is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms which may also be substituted.

[0044] When it is a composition for forming a metal oxide film containing such a (B) fluidity promoter, the fluidity further increases, so it is more effective for filling a high aspect ratio pattern substrate. When the contents of the above general formula (1) and the above general formula (2) are within the above ranges, various physical properties required when forming a metal oxide film, such as filling characteristics, dry etching resistance, and substrate adhesion, are adjusted within an appropriate range. Moreover, by adjusting the contents of the general formula (1) and the general formula (2) in accordance with the surface state of the metal oxide nanoparticles, the dispersion stability of the metal oxide nanoparticles in the composition can be improved.

[0045] The aforementioned (C) dispersion stabilizer preferably has a weight reduction rate of less than 30% at 30 °C to 190 °C and a weight reduction rate of 98% or more between 30 °C and 350 °C.

[0046] Since it has the characteristics of a weight reduction rate of less than 30% at 30 °C to 190 °C and a weight reduction rate of 98% or more between 30 °C and 350 °C, it helps to improve the fluidity during the coating of the composition and is removed from the film after baking at 350 °C. Therefore, the filling / planarization characteristics can be improved without deteriorating the dry etching resistance. In addition, it can also suppress the occurrence of defects caused by drying and contribute to the improvement of the semiconductor manufacturing yield.

[0047] The aforementioned (C) dispersion stabilizer preferably contains one or more compounds selected from the following general formulas (I) to (III).

[0048] [Chemical formula 5]

[0049]

[0050] In the formula, R 1 are each independently a hydrogen atom, a hydroxyl group, or an organic group having 1 to 10 carbon atoms which may also be substituted. W 1 is a phenylene group or a divalent group represented by the following general formula (I-1). W2 , W 3 is a single bond or any divalent group represented by the following general formula (I-2). m 1 is an integer from 1 to 10, and n 1 is an integer from 0 to 5.

[0051] [Chemical formula 6]

[0052]

[0053] In the formula, * represents the bonding position, and R 10 , R 11 , R 12 , R 13 is a hydrogen atom, a hydroxyl group, or an organic group having 1 to 10 carbon atoms. W 10 , W 11 each independently represents a single bond or a carbonyl group. m 10 , m 11 is an integer from 0 to 10, and m 10 + m 11 ≥ 1.

[0054] [Chemical formula 7]

[0055]

[0056] In the formula, * represents the bonding position.

[0057] [Chemical formula 8]

[0058]

[0059] In the formula, R 2 each independently is a hydrogen atom, or an organic group having 1 to 10 carbon atoms which may also be substituted. W 4 is any divalent group represented by the following general formula (II-1). W 5 is a single bond or a divalent group represented by the following general formula (II-2). m 2 is an integer from 2 to 10, and n 3 is an integer from 0 to 5.

[0060] [Chemical formula 9]

[0061]

[0062] In the formula, * represents the bonding position, and R 20 , R 21 , R 22 , R 23 is a hydrogen atom, a hydroxyl group, or an organic group having 1 to 10 carbon atoms. m 20 , m 21 is an integer from 0 to 10, and m 20 + m21 ≥1.

[0063] [Chemical formula 10]

[0064]

[0065] In the formula, * represents the bonding position.

[0066] [Chemical formula 11]

[0067]

[0068] In the formula, R 3 , R 4 is a hydrogen atom, a hydroxyl group, or an optionally substituted organic group having 1 to 10 carbon atoms, and may also be bonded to form a cyclic structure. R 5 , R 6 is an organic group having 1 to 10 carbon atoms, R 5 is a group containing either an aromatic ring or a divalent group represented by the following general formula (III-1). W 6 , W 7 is a single bond or any divalent group represented by the following general formula (III-2), and at least one is a divalent group represented by the following general formula (III-2).

[0069] [Chemical formula 12]

[0070]

[0071] In the formula, * represents the bonding position, and W 30 is an organic group having 1 to 4 carbon atoms.

[0072] [Chemical formula 13]

[0073]

[0074] In the formula, * represents the bonding position.

[0075] By using a dispersion stabilizer having an aromatic ring as the hydrophobic part and a structure having an oxygen atom such as the (C-1) structure as the hydrophilic part, a composition for forming a metal oxide film excellent in dispersibility / stability of metal oxide nanoparticles can be prepared even in a composition in which the concentration of the resin for promoting fluidity is 9% by mass or more.

[0076] Preferably, the aforementioned (A) metal oxide nanoparticles are one or more of metal oxide nanoparticles selected from the group consisting of zirconium, hafnium, aluminum, tungsten, titanium, copper, tin, cerium, indium, zinc, yttrium, lanthanum, chromium, cobalt, platinum, iron, antimony, and germanium.

[0077] By using such metal oxide nanoparticles, a composition for forming a metal oxide film with excellent dispersibility / stability of metal nanoparticles can be prepared.

[0078] The aforementioned (A) metal oxide nanoparticles are preferably at least one selected from the group consisting of zirconium oxide nanoparticles, hafnium oxide nanoparticles, tungsten oxide nanoparticles, titanium oxide nanoparticles, and tin oxide nanoparticles.

[0079] By using such metal oxide nanoparticles, a metal oxide film with excellent etching resistance can be formed.

[0080] The aforementioned (A) metal oxide nanoparticles preferably have an average primary particle size of 100 nm or less.

[0081] By using such metal oxide nanoparticles, a composition for forming a metal oxide film with excellent dispersibility and fluidity of metal nanoparticles can be prepared.

[0082] The weight ratio of the aforementioned (A) metal oxide nanoparticles to the aforementioned (B) fluidity promoter is preferably 80 / 20 to 10 / 90.

[0083] For the composition for forming a metal oxide film with the ratio of (A) to (B) in such a range, various physical properties required for forming a metal oxide film, such as filling characteristics, dry etching resistance, and substrate adhesion, can be adjusted within an appropriate range. Moreover, a composition for forming a metal oxide film can be provided without impairing the dispersion stability of the metal oxide nanoparticles in the composition.

[0084] The aforementioned composition for forming a metal oxide film preferably further contains at least one of a crosslinking agent, a surfactant, and an acid generator.

[0085] For the composition for forming a metal oxide film containing the above additives, the coating property, dry etching resistance, and filling characteristics are more excellent.

[0086] Furthermore, the present invention is a patterning method, a method for forming a pattern on a substrate to be processed, including the following steps:

[0087] (I-1) After coating the above composition for forming a metal oxide film on the substrate to be processed, heat treatment is performed to form a metal oxide film.

[0088] (I-2) An upper resist film is formed on the metal oxide film using a photoresist material.

[0089] (I-3) After pattern exposure of the upper resist film, development is performed with a developer to form a pattern on the upper resist film.

[0090] (I-4) Using the resist upper layer film with the formed pattern as a mask, transfer the pattern onto the metal oxide film by dry etching, and

[0091] (I-5) Using the metal oxide film with the formed pattern as a mask, process the substrate to be processed to form a pattern on the substrate to be processed.

[0092] According to the above-described pattern formation method using two-layer resist treatment, a fine pattern can be formed on the object to be processed (substrate to be processed).

[0093] Furthermore, the present invention is a pattern formation method, which is a method for forming a pattern on a substrate to be processed, and includes the following steps:

[0094] (II-1) After coating the above-described composition for forming a metal oxide film on the substrate to be processed, perform heat treatment to form a metal oxide film,

[0095] (II-2) Form a silicon-containing resist intermediate film on the metal oxide film using a silicon-containing resist intermediate film material,

[0096] (II-3) Form a resist upper layer film on the silicon-containing resist intermediate film using a photoresist material,

[0097] (II-4) After subjecting the resist upper layer film to pattern exposure, develop it with a developer to form a pattern on the resist upper layer film,

[0098] (II-5) Using the resist upper layer film with the formed pattern as a mask, transfer the pattern onto the silicon-containing resist intermediate film by dry etching,

[0099] (II-6) Using the silicon-containing resist intermediate film with the transferred pattern as a mask, transfer the pattern onto the metal oxide film by dry etching step, and

[0100] (II-7) Using the metal oxide film with the formed pattern as a mask, process the substrate to be processed to form a pattern on the substrate to be processed.

[0101] According to the above-described pattern formation method using three-layer resist treatment, a fine pattern can be formed on the substrate to be processed with high precision.

[0102] Furthermore, the present invention is a pattern formation method, which is a method for forming a pattern on a substrate to be processed, and includes the following steps:

[0103] (III-1) After coating the above-described composition for forming a metal oxide film on the substrate to be processed, perform heat treatment to form a metal oxide film,

[0104] (III-2) Form an inorganic hard mask intermediate film selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film on the metal oxide film,

[0105] (III-3) Form an organic thin film on the inorganic hard mask intermediate film.

[0106] (III-4) Form an upper resist film on the organic thin film using a photoresist material.

[0107] (III-5) After pattern exposure of the upper resist film, develop it with a developer to form a pattern on the upper resist film.

[0108] (III-6) Use the patterned upper resist film as a mask and transfer the pattern to the organic thin film and the inorganic hard mask intermediate film by dry etching.

[0109] (III-7) Use the inorganic hard mask intermediate film with the transferred pattern as a mask and transfer the pattern to the metal oxide film step by dry etching, and

[0110] (III-8) Use the patterned metal oxide film as a mask and process the substrate to be processed to form a pattern on the substrate to be processed.

[0111] According to the above pattern formation method using a four-layer resist process, a fine pattern can be formed on the substrate to be processed with high precision.

[0112] Furthermore, the present invention is a pattern formation method for forming a pattern on a substrate to be processed, comprising the following steps:

[0113] (IV-1) Form a lower resist film on the substrate to be processed.

[0114] (IV-2) Form a resist intermediate film, or a combination of an inorganic hard mask intermediate film selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film and an organic thin film, on the lower resist film.

[0115] (IV-3) Use a photoresist material to form an upper resist film on the resist intermediate film, or the combination of the inorganic hard mask intermediate film and the organic thin film.

[0116] (IV-4) After pattern exposure of the upper resist film, develop it with a developer to form a pattern on the upper resist film.

[0117] (IV-5) Use the patterned upper resist film as a mask and transfer the pattern to the resist intermediate film, or the organic thin film and the inorganic hard mask intermediate film, by dry etching.

[0118] (IV-6) Use the resist intermediate film with the transferred pattern, or the inorganic hard mask intermediate film, as a mask and transfer the pattern to the lower resist film by dry etching.

[0119] (IV-7) After coating the above-described composition for forming a metal oxide film on the resist underlayer film having the formed pattern, heat treatment is performed to coat the metal oxide film, and the spaces between the patterns of the resist underlayer film are filled with the metal oxide film.

[0120] (IV-8) The metal oxide film coated on the resist underlayer film having the formed pattern is etched back by chemical stripping or dry etching to expose the top surface of the resist underlayer film having the formed pattern.

[0121] (IV-9) The resist intermediate film or the inorganic hard mask intermediate film remaining on the top surface of the resist underlayer film is removed by dry etching.

[0122] (IV-10) The resist underlayer film having the formed pattern whose surface is exposed is removed by dry etching to form an inverted pattern of the original pattern on the metal oxide film.

[0123] (IV-11) Using the metal oxide film having the formed inverted pattern as a mask, the substrate to be processed is processed to form a tone-inverted pattern on the substrate to be processed.

[0124] According to the pattern forming method using the above-described inversion process, a fine pattern can be formed on the substrate to be processed with higher precision.

[0125] Provided is a pattern forming method using a composition for forming a metal oxide film in a pattern forming method of a sacrificial film, including the following steps:

[0126] (V-1) After coating the above-described composition for forming a metal oxide film on the substrate to be processed having a structure or height difference, heat treatment is performed to fill the metal oxide film.

[0127] (V-2) The metal oxide film outside the structure or height difference on the substrate to be processed is removed by CMP, and the metal oxide film is removed from the surface of the substrate to be processed.

[0128] (V-3) An insulating film and a conductive film are alternately laminated on the substrate to be processed filled with the metal oxide film.

[0129] (V-4) An organic resist underlayer film is formed on the laminated film of the insulating film and the conductive film formed on the substrate to be processed filled with the metal oxide film.

[0130] (V-5) A 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, or a combination of the inorganic hard mask intermediate film and an organic thin film is formed on the organic resist underlayer film.

[0131] (V-6) On the resist intermediate film, or the inorganic hard mask intermediate film, or a combination of the inorganic hard mask intermediate film and the organic thin film, a resist upper layer film is formed using a photoresist material.

[0132] (V-7) After the resist upper layer film is pattern-exposed, it is developed with a developer to form a pattern on the resist upper layer film.

[0133] (V-8) Using the patterned resist upper layer film as a mask, the pattern is transferred to the resist intermediate film, or the inorganic hard mask intermediate film, or the organic thin film and the inorganic hard mask intermediate film by dry etching.

[0134] (V-9) Using the resist intermediate film or the inorganic hard mask intermediate film with the transferred pattern as a mask, the pattern is transferred to the resist lower layer film by dry etching.

[0135] (V-10) Using the resist lower layer film with the transferred pattern as a mask, the pattern is transferred to the stacked film of the insulating film and the conductive film by dry etching.

[0136] (V-11) Using the stacked film of the insulating film and the conductive film with the transferred pattern as a mask, the metal oxide film filled on the substrate to be processed is removed.

[0137] According to the above pattern formation method, a multi-stack structure in 3D-NAND manufacturing can be formed, which can contribute more to high stacking.

[0138] The above insulating film can be formed of any suitable (a plurality of) insulating materials. For example, although not limited, the insulating material may contain silicon oxide (e.g., SiO2). The conductive film can be formed of any suitable (a plurality of) conductive materials. It may contain one or more of polysilicon, and metals such as tungsten, nickel, titanium, platinum, aluminum, gold, tungsten nitride, tantalum nitride, titanium nitride, and silicon nitride. The formation methods of each conductive material and insulating material are not described in detail in this specification, but can be formed according to known techniques.

[0139] It is preferable to use a substrate having a structure with an aspect ratio of 5 or more or a height difference for the substrate to be processed.

[0140] In the present invention, the substrate to be processed can be, for example, the above-mentioned one.

[0141] Further, the present invention provides a method for forming a metal oxide film, which is a method for forming a metal oxide film acting as a planar film used in the manufacturing process of a semiconductor device. The substrate coated with the above-mentioned composition for forming a metal oxide film on the substrate to be processed is heat-treated at a temperature of 100 °C or more and 600 °C or less for 10 to 600 seconds to form a hardened film.

[0142] Furthermore, the present invention provides a method for forming a metal oxide film, which is a method for forming a metal oxide film serving as a planarizing film used in the manufacturing process of a semiconductor device. A substrate coated with the composition for forming the metal oxide film on a processed substrate is heat-treated in a gas environment with an oxygen concentration of 1% by volume or more and 21% by volume or less to form a hardened film.

[0143] According to such a method, the crosslinking reaction of the composition for forming the metal oxide film during the formation of the underlayer film of the resist is promoted, and the mixing with the upper layer film is more highly suppressed. Further, by appropriately adjusting the heat treatment temperature, time, and oxygen concentration within the above ranges, the filling / planarizing characteristics and hardening characteristics of the metal oxide film suitable for the intended use can be obtained.

[0144] Furthermore, the present invention provides a method for forming a metal oxide film, which is a method for forming a metal oxide film serving as a planarizing film used in the manufacturing process of a semiconductor device. A substrate coated with the composition for forming the metal oxide film on a processed substrate is heat-treated in a gas environment with an oxygen concentration of less than 1% by volume to form a hardened film.

[0145] According to such a method, even when the processed substrate contains a material that is unstable to heating in an oxygen environment, the deterioration of the processed substrate can be prevented, the crosslinking reaction of the composition for forming the metal oxide film during the formation of the metal oxide film is promoted, and the mixing with the upper layer film is more highly suppressed, which is useful.

[0146] [Effects of the Invention]

[0147] As described above, the composition for forming a metal oxide film, the pattern forming method, and the metal oxide film forming method of the present invention are particularly suitable for multi-layer resist processing including a filling / planarization step of a processed substrate having height differences and unevenness, and are extremely useful for fine patterning in semiconductor device manufacturing. Specifically, since it contains a flowability promoter with excellent cracking resistance, a film with excellent dry etching resistance derived from metal oxide nanoparticles can be formed as a thick film. Further, since it has a dispersion stabilizer capable of further enhancing the thermal flowability of the resin for the flowability promoter, a composition for forming a metal oxide film can be provided as a resist underlayer film material for a high aspect ratio pattern substrate that cannot be filled without voids by metal oxide nanoparticles alone. Moreover, due to the dispersion stabilizer having a specific structure, even in a high-concentration liquid composition with a resin content of 9% by mass or more, the nanoparticles can maintain a good dispersed state, and a composition for forming a metal oxide film with excellent storage stability can be provided. In the fine patterning process using the multi-layer resist method in the semiconductor device manufacturing step, even on a processed substrate having a portion with difficult filling / planarization such as a high aspect ratio pattern substrate typified by a 3D-NAND memory where high stacking progresses, it can be filled without generating defects such as voids and peeling. Further, for a known coating-type organic resist underlayer film material, a film with extremely excellent dry etching resistance can be formed as a thick film, and fine patterns can be formed with higher precision on the workpiece. BRIEF DESCRIPTION OF THE DRAWINGS

[0148] Figure 1 (A) to (F) are explanatory diagrams of an example (3-layer resist process) of the pattern forming method of the present invention.

[0149] Figure 2 (G) to (P) are explanatory diagrams of an example of the tone inversion type pattern forming method of the present invention (inversion of the SOC pattern in the 3-layer resist process).

[0150] Figure 3 (Q) to (Z) are explanatory diagrams of an example of the pattern forming method using the sacrificial film of the present invention.

[0151] Figure 4 (AA) to (AC) are explanatory diagrams of the filling property evaluation method. DETAILED DESCRIPTION OF THE INVENTION

[0152] As described above, in the fine patterning process using a multilayer resist method in the semiconductor device manufacturing step, even on a substrate to be processed in a portion where filling / planarization is difficult, such as a dense portion of a fine pattern structure having a high aspect ratio typified by a 3D-NAND memory in which high stacking progress has occurred, it is possible to perform filling / planarization without generating defects such as voids and peeling, and it has excellent dry etching resistance for a known coating-type organic resist underlayer film material, and a thick film resist underlayer film material capable of transferring a resist pattern to the substrate to be processed with higher precision.

[0153] The inventors of the present application have diligently explored the above problems. In the multilayer resist method using a resist underlayer film, in order to achieve both a high degree of filling / planarization achieved by forming the underlayer film and excellent dry etching resistance, various resist underlayer film materials and pattern formation methods have been explored. As a result, it has been found that a pattern formation method using a metal oxide film-forming composition composed of metal oxide nanoparticles having excellent dry etching resistance, a fluidity promoter containing a resin having a specific structure with excellent cracking resistance, and a dispersion stabilizer that effectively enhances the resin fluidity and storage stability is very effective, and thus the present invention has been completed.

[0154] That is, the present invention is a metal oxide film-forming composition, characterized by comprising:

[0155] (A) Metal oxide nanoparticles,

[0156] (B) A fluidity promoter containing a resin having a structural unit represented by the following general formula (1),

[0157] (C) A dispersion stabilizer composed of an aromatic-containing compound having two or more benzene rings, or one benzene ring and a structure represented by the following general formula (C-1) and having a molecular weight of 500 or less in terms of molecular formula, and

[0158] (D) An organic solvent,

[0159] The content of the (B) fluidity promoter in the entire composition is 9% by mass or more, the ratio Mw / Mn of the weight average molecular weight Mw to the number average molecular weight Mn in terms of polystyrene measured by gel permeation chromatography is 2.50 ≤ Mw / Mn ≤ 9.00, and it does not contain a compound or polymer having a cardo structure.

[0160] [Chemical formula 14]

[0161]

[0162] In the aforementioned general formula (1), R ais a saturated monovalent organic group having 1 to 30 carbon atoms or an unsaturated monovalent organic group having 2 to 30 carbon atoms, X is a divalent organic group having 1 to 30 carbon atoms, p is an integer from 0 to 5, q 1 is an integer from 1 to 6, p + q 1 is an integer greater than or equal to 1 and less than or equal to 6, q 2 is 0 or 1.

[0163] [Chemical Formula 15]

[0164]

[0165] In the formula, * represents the bonding position, and W is an organic group having 1 to 4 carbon atoms.

[0166] The following is a detailed description of the present invention, but the present invention is not limited to these contents.

[0167] <Composition for forming metal oxide film>

[0168] The composition for forming a metal oxide film of the present invention contains (A) metal oxide nanoparticles described below, (B) a fluidity promoter represented by a specific general formula, (C) a dispersion stabilizer composed of an aromatic compound having two or more benzene rings, or one benzene ring and a structure represented by the following general formula (C-1) and having a molecular weight of 500 or less in terms of molecular formula, and (D) an organic solvent.

[0169] The content of the (B) fluidity promoter relative to the entire composition is 9% by mass or more, the ratio Mw / Mn of the weight average molecular weight Mw to the number average molecular weight Mn in terms of polystyrene measured by gel permeation chromatography is 2.50 ≤ Mw / Mn ≤ 9.00, and it does not contain compounds and polymers having a cardo structure. The composition for forming a metal oxide film of the present invention may also contain additives such as surfactants and crosslinking agents as needed. The components contained in the composition of the present invention are described below.

[0170] <(A) Metal oxide nanoparticles>

[0171] The aforementioned (A) metal oxide nanoparticles contained in the composition for forming a metal oxide film of the present invention are preferably one or more of metal oxide nanoparticles selected from the group consisting of zirconium, hafnium, aluminum, tungsten, titanium, copper, tin, cerium, indium, zinc, yttrium, lanthanum, chromium, cobalt, platinum, iron, antimony, and germanium. Among them, from the viewpoints of dispersibility and dry etching resistance, zirconia nanoparticles, hafnia nanoparticles, tungsten oxide nanoparticles, titanium oxide nanoparticles, and tin oxide nanoparticles are more desirable.

[0172] By selecting the above metal oxides, a metal oxide film having excellent dispersibility and dry etching resistance can be formed.

[0173] The aforementioned (A) metal oxide nanoparticles preferably have an average primary particle diameter of 100 nm or less, more preferably 50 nm or less, still more preferably 30 nm or less, and particularly preferably 15 nm or less. The average primary particle diameter of the aforementioned metal oxide nanoparticles before being dispersed in an organic solvent can be determined by a method of directly measuring the size of primary particles from an electron microscope photograph. Specifically, the minor axis diameter and major axis diameter of each primary particle are measured, and their average is taken as the particle diameter of this particle. Then, for 100 or more particles, the volume (mass) of each particle is obtained by approximating the cuboid of the obtained particle diameter, and the volume average diameter is obtained and defined as the average diameter. Also, the same result can be obtained using a transmission type (TEM), a scanning type (SEM), or a scanning transmission type (STEM) electron microscope.

[0174] If in such a particle diameter range, good dispersibility can be exhibited in the composition for forming a metal oxide film, and a metal oxide film with excellent filling / flattening characteristics for a dense portion of a fine pattern structure can be formed.

[0175] The (A) metal oxide nanoparticles contained in the composition for forming a metal oxide film of the present invention can use commercially available metal oxide nanoparticles.

[0176] Titanium oxide nanoparticles, for example, TTO series (TTO-51(A), TTO-51(C), etc.), TTO-S, V series (TTO-S-1, TTO-S-2, TTO-V-3, etc.) manufactured by Ishihara Sangyo Co., Ltd.; MT series (MT-01, MT-05, MT-100SA, MT-500SA, NS405, etc.) manufactured by TAYCA Corporation; STR-100A-LP manufactured by Sakai Chemical Industry Co., Ltd.

[0177] Zirconium oxide nanoparticles, for example: PCS (manufactured by Nippon Denko Corporation), JS-01, JS-03, JS-04 (manufactured by Nippon Denko Corporation), UEP, UEP-50, UEP-100 (manufactured by Daiichi Rare Earth Chemical Industry Co., Ltd.); PCPB-2-50-PGA and PCPA-2-502-PGA (manufactured by Pixelligent Technologies); ZrO 2 nanoparticles 915505 (manufactured by Sigma-Aldrich), SZR-M, SZR-K, SZR-En10 (manufactured by Sakai Chemical Industry Co., Ltd.); zirconium oxide nanoparticle dispersion ZIRCOSTAR ZP-153, HR-101 (manufactured by Nippon Catalyst Co., Ltd.), etc.

[0178] The above-mentioned (A) metal oxide nanoparticles contained in the composition for forming a metal oxide film of the present invention can be used alone or in combination of two or more, and any combination can be selected according to the required performance. The component (A) can be set to 11 to 400 parts by mass relative to 100 parts by mass of the fluidity promoter in the composition.

[0179] <(B) Fluidity promoter>

[0180] The composition for forming a metal oxide film of the present invention is characterized in that it contains a (B) fluidity promoter which is a resin having a structural unit represented by the following general formula (1), contains 9% by mass or more relative to the whole composition, and does not contain a compound or polymer having a cardo structure.

[0181] [Chemical formula 16]

[0182]

[0183] In the above general formula (1), R a is a saturated monovalent organic group having 1 to 30 carbon atoms or an unsaturated monovalent organic group having 2 to 30 carbon atoms, X is a divalent organic group having 1 to 30 carbon atoms, p is an integer of 0 to 5, q 1 is an integer of 1 to 6, p + q 1 is an integer of 1 or more and 6 or less, q 2 is 0 or 1.

[0184] If the content of the above-mentioned (B) fluidity promoter is 9% by mass or more, a metal oxide film with a large thickness can be formed. Therefore, it is considered that even on a processed substrate having a portion with a large aspect ratio and particularly difficult to fill, the filling characteristics are excellent, and a resist underlayer film can be formed without defects such as pores and peeling. Considering the higher aspect ratio of the filling pattern accompanying the further high stacking of 3D-NAND, the content of the above-mentioned (B) fluidity promoter is preferably 15% by mass or more, and more preferably 20% by mass or more.

[0185] By the above-mentioned (B) fluidity promoter not containing a compound or polymer having a cardo structure, a thick film metal oxide film with excellent cracking resistance can be formed. The fluorene ring having a cardo structure has a rigid structure and a large steric hindrance, and can form a film with excellent heat resistance. However, high-carbon materials are likely to crack due to thermal shrinkage during baking and are not suitable for forming thick films.

[0186] Not limited to the cardo structure, it is preferably not to contain a resin with a high carbon content. Using a composition that dissolves only the fluidity promoter in the solvent component without using the nanoparticle component to form a coating film on the substrate, and the carbon content rate of the above-mentioned (B) fluidity promoter measured after baking the formed film at 350 °C for about 60 seconds is preferably 90% by mass or less, and more preferably 85% by mass or less as measured by elemental analysis.

[0187] In the above general formula (1), R a represents a saturated monovalent organic group having 1 to 30 carbon atoms or an unsaturated monovalent organic group having 2 to 30 carbon atoms. For example: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, tert-pentyl and other monovalent saturated hydrocarbon groups, vinyl, propenyl, butenyl, pentenyl, ethynyl, propynyl and other monovalent unsaturated chain hydrocarbon groups, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl and other monocyclic saturated cyclic hydrocarbon groups, cyclobutenyl, cyclopentenyl, cyclohexenyl and other monovalent monocyclic unsaturated cyclic hydrocarbon groups, norbornyl, adamantyl and other monovalent polycyclic cyclic hydrocarbon groups, phenyl, methylphenyl, naphthyl, methylnaphthyl, anthryl, methylanthryl and other monovalent aromatic hydrocarbon groups, etc.

[0188] The above R a representative organic groups may include alkoxy groups such as methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentyloxy, n-hexyloxy, etc., alkoxycarbonyl groups such as methoxycarbonyl, ethoxycarbonyl, n-propoxycarbonyl, isopropoxycarbonyl, n-butoxycarbonyl, isobutoxycarbonyl, sec-butoxycarbonyl, tert-butoxycarbonyl, n-pentyloxycarbonyl, n-hexyloxycarbonyl, etc.

[0189] Some or all of the hydrogen atoms possessed by the above saturated hydrocarbon groups, unsaturated chain hydrocarbon groups, monocyclic saturated cyclic hydrocarbon groups, monocyclic unsaturated cyclic hydrocarbon groups, polycyclic cyclic hydrocarbon groups, aromatic hydrocarbon groups, alkoxy groups, alkoxycarbonyl groups, etc. may also be substituted, and the substituents are, for example: halogen atoms such as fluorine atom, chlorine atom, bromine atom, iodine atom, hydroxyl group, cyano group, carboxyl group, nitro group, amino group, alkoxy group, alkoxycarbonyl group, acyl group, alkoxycarbonyloxy group, aryl group, aliphatic heterocyclic groups such as lactone group, aromatic heterocyclic groups such as furyl group, pyridyl group, etc.

[0190] Regarding the organic group represented by the above R a from the perspective of obtaining raw materials, for example, methyl is preferred.

[0191] In the above general formula (1), the divalent organic group having 1 to 30 carbon atoms represented by X, for example: methylene, ethanediyl, propanediyl, butanediyl, pentanediyl, hexanediyl, octanediyl, decanediyl and other alkanediyl groups, cyclopropanediyl, cyclobutanediyl, cyclopentanediyl, cyclohexanediyl, cycloheptanediyl, cyclooctanediyl, cyclodecanediyl, methylcyclohexanediyl, ethylcyclohexanediyl and other monocyclic cycloalkanediyl groups, bicyclo[2.2.1]heptanediyl, bicyclo[2.2.2]octanediyl, tricyclo[5.2.1.0 2,6 decane diyl (bicyclopentylene), tricyclo[3.3.1.1 3，7 decane diyl, tetracyclo[6.2.1.13,6 .0 2,7 Dicycloalkylene such as dodecylene and adamantylene, and aromatic (arene) diyl such as phenylene and naphthylene.

[0192] The alkyldiyloxy represented by X above, for example: a group formed by combining the above alkyldiyl with an oxygen atom. Further, the cycloalkyldiyloxy represented by X above, for example, a group formed by combining the above cycloalkyldiyl with an oxygen atom.

[0193] Part or all of the hydrogen atoms possessed by the above alkyldiyl, cycloalkyldiyl, alkyldiyloxy, cycloalkyldiyloxy, and aromatic diyl may also be substituted, and examples of the substituents may be the same as those of the organic group represented by R above. a Examples of the substituents that the organic group represented by R above may also possess are the same groups.

[0194] Examples of the organic group represented by X above are groups represented by the following formula.

[0195] [Chemical formula 17]

[0196]

[0197] In the above formula, * represents an atomic bond.

[0198] Regarding X above, from the perspective of obtaining raw materials, methylene is preferred.

[0199] (B) Resins having a structural unit represented by the above general formula (1) are specifically listed as follows.

[0200] [Chemical formula 18]

[0201]

[0202] [Chemical formula 19]

[0203]

[0204] The ratio Mw / Mn of the weight-average molecular weight Mw to the number-average molecular weight Mn in terms of polystyrene obtained by gel permeation chromatography of the above (B) flowability promoter is 2.50 ≤ Mw / Mn ≤ 9.00, and 3.00 ≤ Mw / Mn ≤ 8.00 is preferred.

[0205] If the dispersion degree is such, the thermal flowability of the resin contained in the flowability promoter will become better, and when blended into the composition, it can well fill the fine structure already formed on the substrate. Moreover, it can form a flat anti-reflective coating film on the entire substrate.

[0206] The weight-average molecular weight Mw in terms of polystyrene obtained by gel permeation chromatography of the above-mentioned (B) flow promoter is preferably 1,500 ≤ Mw ≤ 20,000, more preferably 3,000 ≤ Mw ≤ 15,000, and particularly preferably 4,000 ≤ Mw ≤ 12,000.

[0207] If it is within such a molecular weight range, the thermal fluidity of the resin contained in the flow promoter will become better. When blended in the composition, it can well fill the fine structure formed on the substrate. Moreover, it can form an underlayer film of the resist that is flat over the entire substrate. Also, it can form a metal oxide film with excellent film thickness uniformity and a small amount of sublimated substances.

[0208] In addition to the resin having the structural unit represented by the above general formula (1), the above-mentioned (B) flow promoter may further contain a resin having the structural unit represented by the following general formula (2).

[0209] [Chemical formula 20]

[0210]

[0211] In the above general formula (2), R a is a saturated monovalent organic group having 1 to 30 carbon atoms or an unsaturated monovalent organic group having 2 to 30 carbon atoms, R b is a saturated hydrocarbon group having 1 to 30 carbon atoms or an unsaturated hydrocarbon group having 2 to 10 carbon atoms, X is a divalent organic group having 1 to 30 carbon atoms, p is an integer of 0 to 5, q 1 is an integer of 1 to 6, p + q 1 is an integer of 1 or more and 6 or less, q 2 is 0 or 1.

[0212] In the above general formula (2), R b is a saturated monovalent organic group having 1 to 30 carbon atoms or an unsaturated monovalent organic group having 2 to 10 carbon atoms, for example, the same as R a .

[0213] If the above-mentioned flow promoter contains a resin having the structural unit represented by the above general formula (2), the fluidity increases, which is effective for filling a substrate with a higher aspect ratio pattern. Also, because of its low affinity for polar solvents, it is effective for reducing the amount of residual solvent in the filling film.

[0214] Furthermore, the preferred form of the above general formula (2) may include a resin having R b being an alkyl group having 1 to 30 carbon atoms or a structural unit represented by any one of the structures represented by the following general formula (3).

[0215] [Chemical formula 21]

[0216]

[0217] In the general formula (3) above, * represents the bonding site to the oxygen atom, and R A is a divalent organic group having 1 to 10 carbon atoms which may also be substituted, and R B is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms which may also be substituted.

[0218] In the general formula (3) above, the divalent organic group having 1 to 10 carbon atoms represented by R A includes, for example, alkylene groups such as methylene, ethane-1,2-diyl, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, octane-1,8-diyl, decane-1,10-diyl, etc., arylene groups such as phenylene, methylphenylene, naphthalene-1,2-diyl, etc.

[0219] In the general formula (3) above, the monovalent organic group having 1 to 10 carbon atoms represented by R B includes, for example, alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-decyl, etc., aryl groups such as phenyl, tolyl, xylyl, mesityl, naphthyl, etc.

[0220] Part or all of the hydrogen atoms possessed by the above alkylene groups, arylene groups, alkyl groups, aryl groups, etc. may also be substituted, and examples of the substituents are the same groups as those which the organic groups represented by the above R a may also possess.

[0221] Particularly preferred examples include the structures represented below. When having such a structure, a composition for forming a metal oxide film which can provide a filling film having excellent filling properties capable of forming a pattern with a high aspect ratio can be provided. Further, it has good heat resistance and film-forming properties, the generation of sublimates during heat hardening is suppressed, the contamination of the apparatus due to sublimates is suppressed, and the occurrence of coating defects is suppressed.

[0222] [Chemical formula 22]

[0223]

[0224] In the above formula, * represents the bonding site to the oxygen atom.

[0225] By having such a crosslinking group, the fluidity can be further improved, and a cured film having excellent film-forming properties and less outgassing can be formed.

[0226] Polymers having the structural unit represented by the general formula (2) above include, specifically, the following.

[0227] [Chemical formula 23]

[0228]

[0229] When the proportion of the resin having the structural unit of the above general formula (2) is such that, when the proportion of the resin having the structural unit of the above general formula (1) is a and the proportion of the resin having the structural unit of the above general formula (2) is b, it is preferably in the relationship of a + b = 1 and 0.2 ≤ b ≤ 0.8, and more preferably in the relationship of 0.3 ≤ b ≤ 0.7.

[0230] By controlling the proportion of the resin of the above general formula (2) within such a range, the fluidity and the substrate adhesion can be highly exhibited, and a resist underlayer film material with improved filling / planarization characteristics can be provided. When it is desired to improve the film-forming property and the adhesion of the film to the substrate, it is only necessary to increase the proportion a of the resin having a hydroxyl group, that is, a > b. Also, when it is desired to improve the curability, heat resistance, and planarization characteristics, it is only necessary to make a < b, and they can be adjusted to any proportion according to the required performance. Further, by adjusting the contents of the above general formula (1) and the above general formula (2) in accordance with the surface state of the metal oxide nanoparticles, the dispersion stability of the metal oxide nanoparticles in the composition can be improved.

[0231] As described above, not only can two kinds of resins be mixed in a desired proportion, but also an equivalent composition can be prepared by controlling the proportion of substituents in one kind of resin. Specifically, it is a resin having the structural unit represented by the above general formula (1) and the structural unit represented by the following general formula (2) at the same time. In this case, it is preferably prepared by controlling the proportion of the structure constituting R c using the resin represented by the following general formula (4). Specifically, when the proportion of the hydrogen atoms in the structure constituting R c is a and the proportion of the alkyl group having 1 to 30 carbon atoms or the structure represented by the above general formula (3) is b, in terms of the ratio, it is preferably in the relationship of a + b = 1 and the proportion at this time is preferably in the relationship of 0.2 ≤ b ≤ 0.8, and more preferably in the relationship of 0.3 ≤ b ≤ 0.7.

[0232] [Chemical formula 24]

[0233]

[0234] In the above general formula (4), R a , p, q1, q2, and X are the same as above, and R c is a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, or any one of the structures represented by the above general formula (3). Among the structures constituting the above R c , when the proportion of the hydrogen atoms is a and the proportion of the alkyl group having 1 to 30 carbon atoms or the structure represented by the above general formula (3) is b, it is in the relationship of a + b = 1.

[0235] In the composition for forming a metal oxide film of the present invention, the weight ratio of the aforementioned (A) metal oxide nanoparticles to the aforementioned (B) fluidity promoter is preferably 80 / 20 to 10 / 90, more preferably 70 / 30 to 20 / 80, and even more preferably 70 / 30 to 30 / 70.

[0236] By controlling the ratio of the (A) metal oxide nanoparticles and the (B) fluidity promoter within the above range, dry etching resistance and filling / flattening characteristics can be highly exhibited. If it is within the range of 80 / 20 to 10 / 90, a decrease in heat resistance and dry etching resistance will not occur, and thick film formation can be easily achieved. When it is desired to improve dry etching resistance, the ratio of the (A) metal oxide nanoparticles is increased. Also, when it is desired to improve filling / flattening characteristics, the ratio of the (B) fluidity promoter can be increased, and they can be adjusted to any ratio according to the required performance. The amount of the (B) component can be 25 to 900 parts by mass relative to 100 parts by mass of the metal oxide nanoparticles in the composition.

[0237] <(C) Dispersion stabilizer>

[0238] The (C) dispersion stabilizer used in the present invention is a compound represented by a molecular formula having a molecular weight of 500 or less, preferably an aromatic compound containing an oxygen atom and having an aromatic ring.

[0239] When the above (C) dispersion stabilizer is within the above molecular weight range, it exhibits sufficient thermal fluidity during baking, can exhibit a high degree of filling characteristics, and the residue in the baked metal oxide film is reduced. It is more ideal that the molecular weight represented by the molecular formula of the aforementioned dispersion stabilizer is 180 to 500, more ideal is 200 to 450, and particularly preferably 240 to 400.

[0240] When the dispersion stabilizer has a molecular weight of 180 or more, since the dispersion stabilizer is not easily reduced due to evaporation or the like by heat treatment, the thermal fluidity is excellent and the filling / flattening characteristics are sufficient. When the molecular weight exceeds 500, evaporation or the like of the aforementioned dispersion stabilizer caused by heat treatment is suppressed, so the crosslinking reaction of the metal oxide nanoparticles and the fluidity promoter in the composition for forming a metal oxide film and the evaporation of the dispersion stabilizer occur simultaneously, resulting in deterioration of film-forming properties and in-plane uniformity. Also, there is a concern that the dispersion stabilizer remains in the film, leading to deterioration of etching resistance.

[0241] The above aromatic ring needs to be a benzene ring. In addition, for example, aromatic carbocyclic rings such as naphthalene rings, and aromatic heterocyclic rings such as furan rings, pyrrole rings, thiophene rings, phosphazole rings, pyrazole rings, oxazole rings, isoxazole rings, thiazole rings, pyridine rings, pyrazine rings, pyrimidine rings, pyridazine rings, and triazine rings.

[0242] In the composition for forming a metal oxide film of the present invention, a thermal fluidity promoter having an aromatic skeleton is used. If the dispersion stabilizer is an aromatic-containing compound, its compatibility with the resin of the thermal fluidity promoter is excellent, and film formation defects such as pinholes are less likely to occur during film formation, so it is ideal. Furthermore, among aromatic rings, an aromatic carbocyclic ring is more ideal, and a benzene ring is even more ideal.

[0243] Also, examples of the (C) dispersion stabilizer include compounds containing two or more benzene rings, or compounds containing one benzene ring and a structure represented by the following general formula (C-1).

[0244] [Chemical formula 25]

[0245]

[0246] In the formula, * represents the bonding position, and W is an organic group having 1 to 4 carbon atoms.

[0247] More specifically, examples of W include methylene, ethylene, propylene, butylene, trimethylene, and tetramethylene. Among these, ethylene is more ideal.

[0248] For the above-mentioned (C) dispersion stabilizer, it is preferable that the weight reduction rate from 30°C to 190°C is less than 30%, and the weight reduction rate between 30°C and 350°C is 98% or more.

[0249] When the weight reduction rate of the dispersion stabilizer from 30°C to 190°C is less than 30% and the weight reduction rate between 30°C and 350°C is 98% or more, evaporation during heat treatment is suppressed. Thereby, a low viscosity can be sufficiently maintained, the thermal fluidity is excellent, and the residue of the dispersion stabilizer in the metal oxide film after calcination is small, so it is ideal. In this specification, the weight reduction rate is a value obtained based on TG (thermogravimetric) measurement using a differential thermal balance.

[0250] The upper limit of the temperature range in which the weight reduction rate of the dispersion stabilizer is less than 30% is more preferably 210°C, and even more preferably 230°C. By setting the temperature range in which the weight reduction rate of the dispersion stabilizer is less than 30% to the above temperature range, the filling / planarization characteristics can be further improved.

[0251] The temperature at which the weight reduction rate of the dispersion stabilizer becomes 98% or more is more preferably 330°C, and particularly preferably 310°C. By setting the temperature at which the weight reduction rate of the dispersion stabilizer becomes 98% or more to the above temperature range, the residue of the dispersion stabilizer in the metal oxide film after calcination can be further reduced.

[0252] By blending a dispersion stabilizer as described above, the thermal fluidity is improved from the heat treatment of the composition for forming a metal oxide film until hardening due to crosslinking reaction, so the filling / planarization characteristics are excellent. On the other hand, since the dispersion stabilizer is reduced by heat treatment, evaporation, etc., the etching resistance and optical characteristics are not impaired.

[0253] Furthermore, more preferable embodiments of the dispersion stabilizer include one or more compounds selected from the following general formulas (I) to (III).

[0254] [Chemical formula 26]

[0255]

[0256] In the formulas, R 1 are each independently a hydrogen atom, a hydroxyl group, or an optionally substituted organic group having 1 to 10 carbon atoms. W 1 is a phenylene group or a divalent group represented by the following general formula (I-1). W 2 , W 3 is a single bond or any of the divalent groups represented by the following general formula (I-2). m 1 is an integer from 1 to 10, and n 1 is an integer from 0 to 5.

[0257] [Chemical formula 27]

[0258]

[0259] In the formulas, * represents the bonding position, and R 10 , R 11 , R 12 , R 13 are a hydrogen atom, a hydroxyl group, or an organic group having 1 to 10 carbon atoms. W 10 , W 11 each independently represents a single bond or a carbonyl group. m 10 , m 11 are integers from 0 to 10, and m 10 +m 11 ≥1.

[0260] [Chemical formula 28]

[0261]

[0262] In the formulas, * represents the bonding position.

[0263] [Chemical formula 29]

[0264]

[0265] In the formulas, R 2Each independently is a hydrogen atom, or an optionally substituted organic group having 1 to 10 carbon atoms. W 4 Is any divalent group represented by the following general formula (II-1). W 5 Is a single bond or a divalent group represented by the following general formula (II-2). m 2 Is an integer from 2 to 10, n 3 Is an integer from 0 to 5.

[0266] [Chemical formula 30]

[0267]

[0268] In the formula, * represents the bonding position, R 20 , R 21 , R 22 , R 23 Are a hydrogen atom, a hydroxyl group, or an organic group having 1 to 10 carbon atoms. m 20 , m 21 Are integers from 0 to 10, m 20 +m 21 ≥1.

[0269] [Chemical formula 31]

[0270]

[0271] In the formula, * represents the bonding position.

[0272] [Chemical formula 32]

[0273]

[0274] In the formula, R 3 , R 4 Are a hydrogen atom, a hydroxyl group, or an optionally substituted organic group having 1 to 10 carbon atoms, and may also bond to form a ring structure. R 5 , R 6 Are organic groups having 1 to 10 carbon atoms, R 5 Is a group containing either an aromatic ring or a divalent group represented by the following general formula (III-1). W 6 , W 7 Is a single bond or any divalent group represented by the following general formula (III-2), and at least one is a divalent group represented by the following general formula (III-2).

[0275] [Chemical formula 33]

[0276]

[0277] In the formula, * represents the bonding position, W 30 Is an organic group having 1 to 4 carbon atoms.

[0278] [Chemical formula 34]

[0279]

[0280] In the formula, * represents the bonding position.

[0281] In the above general formula (I), R 1 are each independently a hydrogen atom, a hydroxyl group, or an organic group having 1 to 10 carbon atoms which may also be substituted.

[0282] Here, in the present invention, an "organic group" means a group containing at least 1 carbon atom, further containing hydrogen, and may also contain nitrogen, oxygen, sulfur, silicon, halogen atoms, etc.

[0283] R 1 can be a single type or a mixture of multiple types. R 1 More specifically, for example, a hydrogen atom, a hydroxyl group, a methyl group, an ethyl group, a vinyl group, a 2,2,2-trifluoroethyl group, a propyl group, an isopropyl group, an allyl group, a butyl group, a sec-butyl group, a tert-butyl group, an isobutyl group, a pentyl group, a cyclopentyl group, a hexyl group, a cyclohexyl group, a cyclohexenyl group, a decyl group, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a sec-butoxy group, a tert-butoxy group, a norbornyl group, an adamantyl group, a phenyl group, a tolyl group, a xylyl group, a naphthyl group, a benzyl group, a 2-furyl group, a 2-tetrahydrofuryl group. Among these, a hydrogen atom is more preferable.

[0284] W 1 is a phenylene group or a divalent group represented by the above general formula (I-1). W 2 , W 3 is a single bond or any divalent group represented by the above general formula (I-2). m 1 is an integer from 1 to 10, and n 1 are each independently an integer from 0 to 5.

[0285] R 10 , R 11 , R 12 , R 13 are a hydrogen atom, a hydroxyl group, or an organic group having 1 to 10 carbon atoms. More specifically, for example, a hydrogen atom, a hydroxyl group, a methyl group, an ethyl group, a vinyl group, a 2,2,2-trifluoroethyl group, a propyl group, an isopropyl group, an allyl group, a butyl group, a sec-butyl group, a tert-butyl group, an isobutyl group, a pentyl group, a cyclopentyl group, a hexyl group, a cyclohexyl group, a cyclohexenyl group, a decyl group, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a sec-butoxy group, a tert-butoxy group, a norbornyl group, an adamantyl group, a phenyl group, a tolyl group, a xylyl group, a naphthyl group, a benzyl group, a 2-furyl group, a 2-tetrahydrofuryl group. Among these, a hydrogen atom and a methyl group are better, and a hydrogen atom is more preferable.

[0286] W 10 , W 11 each independently represents a single bond or a carbonyl group. m 10, m 11 is an integer from 0 to 10, m 10 +m 11 ≥1.

[0287] R 2 can be a single type or a mixture of multiple types. R 2 More specifically, for example, a hydrogen atom, methyl group, ethyl group, vinyl group, 2,2,2-trifluoroethyl group, propyl group, isopropyl group, allyl group, butyl group, sec-butyl group, tert-butyl group, isobutyl group, pentyl group, cyclopentyl group, hexyl group, cyclohexyl group, cyclohexenyl group, decyl group, methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, sec-butoxy group, tert-butoxy group, norbornyl group, adamantyl group, phenyl group, tolyl group, xylyl group, naphthyl group, benzyl group, 2-furyl group, 2-tetrahydrofuryl group. Among these, a hydrogen atom is more preferable.

[0288] W 4 is a divalent group represented by the above general formula (II-1). W 5 is a single bond or any divalent group represented by the above general formula (II-2). m 2 is an integer from 2 to 10, n 3 is an integer from 0 to 5.

[0289] R 20 , R 21 , R 22 , R 23， More specifically, for example, a hydrogen atom, hydroxyl group, methyl group, ethyl group, vinyl group, 2,2,2-trifluoroethyl group, propyl group, isopropyl group, allyl group, butyl group, sec-butyl group, tert-butyl group, isobutyl group, pentyl group, cyclopentyl group, hexyl group, cyclohexyl group, cyclohexenyl group, decyl group, methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, sec-butoxy group, tert-butoxy group, norbornyl group, adamantyl group, phenyl group, tolyl group, xylyl group, naphthyl group, benzyl group, 2-furyl group, 2-tetrahydrofuryl group. Among these, a hydrogen atom and a methyl group are more preferable, and a hydrogen atom is more ideal.

[0290] m 20 , m 21 is an integer from 0 to 10, m 20 +m 21 ≥1.

[0291] R 3 , R 4is a hydrogen atom, a hydroxyl group, or an organic group having 1 to 10 carbon atoms which may also be substituted. More specifically, for example, a hydrogen atom, a hydroxyl group, a methyl group, an ethyl group, a vinyl group, a 2,2,2-trifluoroethyl group, a propyl group, an isopropyl group, an allyl group, a butyl group, a sec-butyl group, a tert-butyl group, an isobutyl group, a pentyl group, a cyclopentyl group, a hexyl group, a cyclohexyl group, a cyclohexenyl group, a decyl group, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a sec-butoxy group, a tert-butoxy group, a norbornyl group, an adamantyl group, a phenyl group, a tolyl group, a xylyl group, a naphthyl group, a benzyl group, a 2-furyl group, a 2-tetrahydrofuryl group. Among these, a hydrogen atom is more preferable.

[0292] R 6 is an organic group having 1 to 10 carbon atoms. R 5 is an organic group having 1 to 10 carbon atoms, and is a group containing either an aromatic ring or a divalent group represented by the above general formula (III-1). Examples of the organic group having 1 to 10 carbon atoms are the groups exemplified for the above R 3 、R 4 listed groups.

[0293] W 6 、W 7 is a single bond or any of the divalent groups represented by the above general formula (III-2), and at least one of these is a divalent group represented by any of the above general formula (III-2).

[0294] W 30 is an organic group having 1 to 4 carbon atoms. More specifically, for example, a methylene group, an ethylene group, a propylene group, a butylene group, a trimethylene group, a tetramethylene group. Among these, an ethylene group is more preferable.

[0295] The compounds represented by the above general formula (I) can be more specifically exemplified as follows, but are not limited to these.

[0296] [Chemical formula 35]

[0297]

[0298] The compounds represented by the above general formula (II) can be more specifically exemplified as follows, but are not limited to these.

[0299] [Chemical formula 36]

[0300]

[0301] The compounds represented by the above general formula (III) can be more specifically exemplified as follows but are not limited to these.

[0302] [Chemical formula 37]

[0303]

[0304] If the improvement of the dispersion stability of the metal oxide nanoparticles in the metal oxide film forming composition, the film-forming properties, the filling / planarization performance of the substrate, etc. are comprehensively considered, the (C) dispersion stabilizer used in the metal oxide film forming composition of the present invention is preferably an aromatic compound having a benzyl group or a benzoyl group, especially the following aromatic compounds are preferred.

[0305] (i) (Poly)ethylene glycol dibenzoate

[0306] (ii) (Poly)ethylene glycol dibenzyl ether

[0307] (iii) (Poly)propylene glycol dibenzyl ether

[0308] (iv) (Poly)butylene glycol dibenzyl ether

[0309] (v) Straight-chain aliphatic dicarboxylic acid dibenzyl ester

[0310] (vi) (Poly)ethylene glycol monobenzyl ether

[0311] (vii) (Poly)phenylene ether

[0312] [Chemistry 38]

[0313]

[0314] In the above formulae (i) to (vii), n is an integer within the range of 500 or less molecular weight, and is applicable only to these formulae.

[0315] The (C) dispersion stabilizer used in the metal oxide film-forming composition of the present invention has a structure having both a hydrophobic portion composed of an aromatic ring and a hydrophilic portion composed of an O-containing structure such as the (C-1) structure, so even if a high concentration of a fluidity promoter resin necessary for thick film formation is contained, the dispersion stability of the metal oxide nanoparticles is still excellent. Therefore, a metal oxide film-forming composition with excellent storage stability can be provided.

[0316] (C) The amount of the dispersion stabilizer added is preferably 0.1 to 50 parts by mass, more preferably 0.5 to 30 parts by mass, and even more preferably 1 to 10 parts by mass, relative to 100 parts by mass of the metal oxide nanoparticles. If the amount of the dispersion stabilizer added is 0.1% by mass or more, the fluidity of the metal oxide film-forming composition and the dispersion stability effect of the metal oxide nanoparticles can be fully obtained. When the content of the dispersion stabilizer relative to the metal nanoparticles is sufficiently high, the dispersion stabilization effect of the nanoparticles and the effect of improving the thermal fluidity of the metal oxide film are sufficiently high. In addition, when the content of the dispersion stabilizer is not too much, there is no risk of adverse effects on the film-forming properties and dry etching resistance of the obtained coating film.

[0317] The dispersion stabilizer of the present invention can be used alone one of the above aromatic-containing compounds or in combination of two or more thereof.

[0318] <(D) Organic solvent>

[0319] The (D) organic solvent that can be used in the composition for forming a metal oxide film of the present invention is not particularly limited as long as it can disperse the above (A) metal oxide nanoparticles and dissolve the (B) fluidity promoter, (C) dispersion stabilizer, and optionally the crosslinking agent, surfactant, acid generator, and other additives described later. Specifically, solvents with a boiling point of less than 180°C such as those described in paragraphs

[0091] to

[0092] of Japanese Patent Laid-Open No. 2007-199653 can be used. Among them, it is preferable to use propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, 2-heptanone, cyclopentanone, cyclohexanone, and a mixture of two or more of these. The blending amount of the organic solvent is preferably 50 to 1,000 parts, more preferably 70 to 900 parts, and still more preferably 100 to 850 parts with respect to 100 parts of the (B) fluidity promoter.

[0320] If it is such a composition for forming a metal oxide film, the (A) metal oxide nanoparticles can be well dispersed and can be coated by spin coating, so a metal oxide film having both dry etching resistance and a high degree of filling / planarization characteristics can be formed.

[0321] <Other components>

[0322] [Crosslinking agent]

[0323] Furthermore, in the composition for forming a metal oxide film of the present invention, a crosslinking agent may be added in order to improve the curability and further suppress the cross-mixing with the upper layer film. The crosslinking agent is not particularly limited, and various known crosslinking agents of various systems can be widely used. For example, hydroxymethyl or alkoxymethyl type crosslinking agents of polynuclear phenols (polynuclear phenol-based crosslinking agents), 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, and epoxy-based crosslinking agents. When adding the crosslinking agent, the addition amount is preferably 1 to 100 parts, more preferably 5 to 50 parts, with respect to the aforementioned (B) fluidity promoter.

[0324] Specifically, melamine-based crosslinking agents include, for example, hexamethoxymethylated melamine, hexabutoxymethylated melamine, alkoxy and / or hydroxy substituents thereof, and partial self-condensates thereof.

[0325] Specifically, glycoluril-based crosslinking agents include, for example, tetramethoxymethylated glycoluril, tetrabutoxymethylated glycoluril, alkoxy and / or hydroxy substituents thereof, and partial self-condensates thereof.

[0326] Benzoguanamine-based crosslinking agents, specifically, for example, tetramethoxymethylated benzoguanamine, tetrabutoxymethylated benzoguanamine, alkoxy and / or hydroxy substituents thereof, and partial self-condensates thereof.

[0327] Urea-based crosslinking agents, specifically, for example, dimethoxymethylated dimethoxyethyleneurea, alkoxy and / or hydroxy substituents thereof, and partial self-condensates thereof.

[0328] β-Hydroxyalkylamide-based crosslinking agents, specifically, for example, N,N,N’,N’-tetrakis(2-hydroxyethyl)adipamide.

[0329] Isocyanurate-based crosslinking agents, specifically, for example, tris(2,3-epoxypropyl)isocyanurate, triallyl isocyanurate.

[0330] Aziridine-based crosslinking agents, specifically, for example, 4,4’-bis(ethyleneiminocarbonylamino)diphenylmethane, 2,2-bis(hydroxymethyl)butanol-tris[3-(1-aziridinyl)propionate].

[0331] Oxazoline-based crosslinking agents, specifically, for example, 2,2’-isopropylidenebis(4-benzyl-2-oxazoline), 2,2’-isopropylidenebis(4-phenyl-2-oxazoline), 2,2’-methylenebis4,5-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), 2-isopropenyl oxazoline copolymer.

[0332] Epoxy-based crosslinking agents, specifically, for example, 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, pentaerythritol tetraglycidyl ether.

[0333] Polynuclear phenol-based crosslinking agents, specifically, for example, compounds represented by the following general formula (XL-1).

[0334] [Chemical formula 39]

[0335]

[0336] In the formula, Q is a single bond or a q-valent hydrocarbon group having 1 to 20 carbon atoms. R 3 is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. q is an integer of 1 to 5.

[0337] Q is a single bond or an s-valent hydrocarbon group having 1 to 20 carbon atoms. q is an integer of 1 to 5, more preferably 2 or 3. Specifically, Q is, for example, a group obtained by removing q hydrogen atoms from methane, ethane, propane, butane, isobutane, pentane, cyclopentane, hexane, cyclohexane, methylpentane, methylcyclohexane, dimethylcyclohexane, trimethylcyclohexane, benzene, toluene, xylene, ethylbenzene, ethylisopropylbenzene, diisopropylbenzene, methylnaphthalene, ethylnaphthalene, eicosane. R 3 is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. The alkyl group having 1 to 20 carbon atoms is, specifically, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, isopentyl, hexyl, octyl, ethylhexyl, decyl, eicosyl, and a hydrogen atom or methyl is preferred.

[0338] Examples of the compound represented by the above general formula (XL-1) are, specifically, the following compounds. Among them, from the viewpoint of improving the hardening property and film thickness uniformity of the organic film, tris(phenol)methane, tris(phenol)ethane, 1,1,1-tris(4-hydroxyphenyl)ethane, and the hexa(methoxymethyl)ated product of tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene are preferred. R 3 Same as above.

[0339] [Chemical formula 40]

[0340]

[0341] [Chemical formula 41]

[0342]

[0343] [Surfactant]

[0344] In the composition for forming a metal oxide film of the present invention, a surfactant may be added in order to improve the coating property of spin coating. As the surfactant, for example, the surfactants described in

[0142] to

[0147] of Japanese Patent Application Laid-Open No. 2009-269953 can be used. When adding the surfactant, the addition amount is preferably 0.01 to 10 parts, more preferably 0.05 to 5 parts, relative to 100 parts by mass of the aforementioned (B) fluidity promoter.

[0345] [Acid generator]

[0346] In the composition for forming a metal oxide film of the present invention, an acid generator may be added in order to further promote the hardening reaction. As the acid generator, an acid generator that generates acid by thermal decomposition and an acid generator that generates acid by light irradiation can both be added. Specifically, the materials described in paragraphs

[0061] to

[0085] of Japanese Patent Application Laid-Open No. 2007-199653 can be added, but are not limited thereto.

[0347] The above acid generator can be used alone or in combination of two or more. The addition amount of the acid generator, based on 100 parts by mass of the aforementioned (B) fluidity promoter, is preferably 0.05 to 50 parts, more preferably 0.1 to 10 parts.

[0348] [Plasticizer]

[0349] Furthermore, in the composition for forming a metal oxide film of the present invention, in order to further improve the planarization / embedding characteristics, a plasticizer can be added. There is no particular limitation on the plasticizer, and various known plasticizers of various systems can be widely used. For example, low molecular compounds such as phthalates, adipates, phosphates, trimellitates, citrates, etc., polymers such as polyether-based, polyester-based, and polyacetal-based polymers described in JP-A-2013-253227. The addition amount of the plasticizer, based on 100 parts by mass of the aforementioned (B) fluidity promoter, is preferably 1 to 100 parts, more preferably 5 to 30 parts.

[0350] Furthermore, in the composition for forming a metal oxide film of the present invention, as an additive that imparts the same embedding / planarization characteristics as the plasticizer, for example, a liquid additive having a polyethylene glycol or polypropylene glycol structure, or a thermal decomposable polymer having a weight reduction rate of 40% by mass or more between 30°C and 250°C and a weight average molecular weight of 300 to 200,000 is preferably used. This thermal decomposable polymer preferably contains a repeating unit having an acetal structure represented by the following general formulas (DP1) and (DP1a).

[0351] [Chemical formula 42]

[0352]

[0353] In the formula, R 6 is a hydrogen atom or a saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms which may be substituted. Y is a saturated or unsaturated divalent organic group having 2 to 30 carbon atoms.

[0354] [Chemical formula 43]

[0355]

[0356] In the formula, R 6a is an alkyl group having 1 to 4 carbon atoms. Y a is a saturated or unsaturated divalent hydrocarbon group having 4 to 10 carbon atoms, which may also have an ether bond. n represents the average number of repeating units and is 3 to 500.

[0357] [Dispersant]

[0358] In the composition for forming a metal oxide film of the present invention, a general dispersant can be added separately from the above-mentioned (C) dispersion stabilizer. There is no particular limitation on the type of dispersant used, and known dispersants can be used. For example: low molecular weight dispersants such as alkylamines, alkylthiols, alkyl diols, phosphate esters, etc., high molecular weight dispersants having various functional groups, silane coupling agents, etc. Also, high molecular weight dispersants, for example: styrene-based resins (styrene-(meth)acrylic acid copolymers, styrene-maleic anhydride copolymers, etc.), acrylic-based resins ((meth)acrylic acid methyl ester-(meth)acrylic acid copolymers, poly((meth)acrylic acid) and other (meth)acrylic acid-based resins, etc.), water-soluble urethane resins, water-soluble acrylic-based urethane resins, water-soluble epoxy resins, water-soluble polyester-based resins, cellulose derivatives (nitrocellulose; alkyl celluloses such as ethyl cellulose, alkyl-hydroxyalkyl celluloses such as ethyl hydroxyethyl cellulose, hydroxyalkyl celluloses such as hydroxyethyl cellulose, hydroxypropyl cellulose, carboxyalkyl celluloses such as carboxymethyl cellulose and other cellulose ethers, etc.), polyvinyl alcohol, polyalkylene glycols (liquid polyethylene glycol, polypropylene glycol, etc.), natural polymers (polysaccharides such as gelatin, casein, dextrin, gum arabic, etc.), polyvinyl sulfonic acid or its salts, polystyrene sulfonic acid or its salts, formalin condensates of naphthalene sulfonic acid, nitrogen atom-containing high molecular compounds [for example: polyalkyleneimines (polyethyleneimine, etc.), polyvinylpyrrolidone, polyallylamine, polyether polyamines (polyoxyethylene polyamines, etc.) and other high molecular compounds having amino groups], etc. The blending amount of the dispersant is preferably 0.1 to 50 parts by mass, more preferably 0.5 to 30 parts by mass, and even more preferably 1 to 10 parts by mass with respect to 100 parts by mass of the metal oxide nanoparticles.

[0359] By adding the above-mentioned dispersant separately from the above-mentioned (C) dispersion stabilizer, the anti-aggregation property of the metal nanoparticles can be further improved.

[0360] Also, the composition for forming a metal oxide film of the present invention can be used alone or in combination of two or more. The above-mentioned composition for forming a metal oxide film can be used in the applications of metal oxide film materials or planarization materials for semiconductor device manufacturing.

[0361] As described above, in the case of the composition for forming a metal oxide film of the present invention, since it contains the (B) fluidity promoter having excellent cracking resistance, a film having excellent dry etching resistance derived from the (A) metal oxide nanoparticles can be formed as a thick film. Further, since it has the (C) dispersion stabilizer capable of further enhancing the thermal fluidity of the resin for the fluidity promoter, a resist underlayer film material capable of filling a high aspect ratio pattern substrate, which is difficult to achieve with metal oxide nanoparticles alone, without voids can be provided. Furthermore, by having the dispersion stabilizer having a specific structure, even in a high-concentration composition solution having a resin content of 9% by mass or more, the nanoparticles remain in a good dispersed state, and a composition for forming a metal oxide film having excellent storage stability can be provided.

[0362] (Pattern formation method)

[0363] Further, in the present invention, as a pattern formation method using such a composition for forming a metal oxide film by a two-layer resist process,

[0364] A pattern formation method is provided, which is a method for forming a pattern on a substrate to be processed, and has the following steps:

[0365] (I-1) After coating the above-described composition for forming a metal oxide film on the substrate to be processed, heat treatment is performed to form a metal oxide film.

[0366] (I-2) A resist upper layer film is formed on the above-described metal oxide film using a photoresist material.

[0367] (I-3) After pattern exposure of the above-described resist upper layer film, development is performed with a developer to form a pattern on the above-described resist upper layer film.

[0368] (I-4) Using the above-described patterned resist upper layer film as a mask, dry etching is performed to transfer the pattern to the above-described metal oxide film, and

[0369] (I-5) Using the above-described patterned metal oxide film as a mask, the above-described substrate to be processed is processed to form a pattern on the above-described substrate to be processed.

[0370] The resist upper layer film in the above-described two-layer resist process shows resistance to etching with a chlorine-based gas. Therefore, in the above-described two-layer resist process, for the dry etching of the metal oxide film using the resist upper layer film as a mask, it is preferably performed using an etching gas mainly composed of a chlorine-based gas.

[0371] Further, in the present invention, as a pattern formation method using such a composition for forming a metal oxide film by a three-layer resist process,

[0372] A pattern formation method is provided, which is a method for forming a pattern on a substrate to be processed, and has the following steps:

[0373] (II-1) After coating the composition for forming the metal oxide film on the substrate to be processed, heat treatment is performed to form the metal oxide film.

[0374] (II-2) A silicon-containing resist intermediate film is formed on the aforementioned metal oxide film using a silicon-containing resist intermediate film material.

[0375] (II-3) A resist upper film is formed on the aforementioned silicon-containing resist intermediate film using a photoresist material.

[0376] (II-4) After pattern exposure of the aforementioned resist upper film, development is carried out with a developer to form a pattern on the aforementioned resist upper film.

[0377] (II-5) Using the aforementioned patterned resist upper film as a mask, the pattern is transferred to the aforementioned silicon-containing resist intermediate film by dry etching.

[0378] (II-6) Using the aforementioned silicon-containing resist intermediate film with the transferred pattern as a mask, the pattern is transferred to the aforementioned metal oxide film by dry etching, and

[0379] (II-7) Using the aforementioned patterned metal oxide film as a mask, the aforementioned substrate to be processed is processed to form a pattern on the aforementioned substrate to be processed.

[0380] Regarding an example of the three-layer resist process, if Figure 1 is specifically disclosed, it is as follows. In the three-layer resist process, as Figure 1 (A) shown, on the processed layer 2 laminated on the substrate to be processed 1, a metal oxide film (metal-containing resist lower film) 3 is formed using the metal oxide film forming material of the present invention. Thereafter, a resist intermediate film 4 containing silicon atoms is formed, and a resist upper film 5 is formed thereon.

[0381] Next, as Figure 1 (B) shown, the used portion (exposed portion) 6 of the resist upper film 5 is exposed, PEB and development are carried out to form a resist upper film pattern 5a ( Figure 1 (C) shown). Using the obtained resist upper film pattern 5a as a mask, the resist intermediate film 4 containing silicon atoms is etched using a CF-based gas to form a resist intermediate film pattern 4a containing silicon atoms ( Figure 1 (D) shown). After removing the resist upper film pattern 5a, using the obtained resist intermediate film pattern 4a containing silicon atoms as a mask, the metal oxide film 3 is plasma-etched with a chlorine-based gas to form a metal oxide film pattern (metal-containing resist lower film pattern) 3a ( Figure 1(E)). Subsequently, after removing the resist intermediate film pattern 4a containing silicon atoms, the metal oxide film pattern 3a is used as a mask, and the layer to be processed 2 is etched to form a pattern 2a on the layer to be processed. Figure 1 (F)).

[0382] The above three-layer resist-treated silicon-containing resist intermediate film shows resistance to etching with chlorine-based gases. Therefore, in the above three-layer resist treatment, for the dry etching of the metal oxide film using the silicon-containing resist intermediate film as a mask, it is preferably carried out using an etching gas mainly composed of chlorine-based gas.

[0383] The silicon-containing resist intermediate film of the above three-layer resist treatment is also preferably a polysiloxane-based intermediate film. By giving the silicon-containing resist intermediate film an antireflection effect, reflection can be suppressed. Especially for 193 nm exposure applications, if the organic film uses a material containing a large amount of aromatic groups and having a high etching selectivity with respect to the substrate, the k value increases and the substrate reflection increases. However, by giving it an absorption that will result in an appropriate k value for the silicon-containing resist intermediate film, reflection can be suppressed and the substrate reflection can be made 0.5% or less. For the silicon-containing resist intermediate film with an antireflection effect, for 248 nm and 157 nm exposure applications, it is preferably a polysiloxane crosslinked by acid or heat with a suspended anthracenyl group, and for 193 nm exposure applications, it is preferably a polysiloxane with a suspended phenyl group or a light-absorbing group having a Si-Si bond and crosslinked by acid or heat.

[0384] In addition, in the present invention, as a pattern forming method using such a composition for forming a metal oxide film by a four-layer resist treatment, a pattern forming method is provided, which is characterized by having the following steps: forming a metal oxide film on the substrate to be processed using the above composition for forming a metal oxide film, forming a silicon-containing resist intermediate film on the resist underlayer film using a silicon-containing resist intermediate film material, forming an organic antireflection film (BARC) or a conformal film on the silicon-containing resist intermediate film, forming a resist upper layer film on the BARC using a photoresist material, after pattern exposure of the resist upper layer film, developing it with a developer to form a pattern on the resist upper layer film, using the patterned resist upper layer film as a mask, transferring the pattern to the BARC or conformal film and the silicon-containing resist intermediate film by dry etching, using the silicon-containing resist intermediate film with the transferred pattern as a mask, transferring the pattern to the metal oxide film by dry etching, using the metal oxide film with the formed pattern as a mask, processing the substrate to be processed, and forming a pattern on the substrate to be processed.

[0385] Alternatively, an inorganic hard mask may be formed without forming a silicon-containing resist intermediate film. In this case, at least on the object to be processed, a metal oxide film is formed using the composition for forming a metal oxide film of the present invention, an inorganic hard mask selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film is formed on the metal oxide film, a resist upper film is formed on the inorganic hard mask using a photoresist composition, a circuit pattern is formed on the resist upper film, the patterned resist upper film is used as a mask to etch the inorganic hard mask, the patterned inorganic hard mask is used as a mask to etch the metal oxide film, and then the patterned metal oxide film is used as a mask to etch the object to be processed to form a pattern on the object to be processed, whereby a semiconductor device circuit pattern can be formed on the substrate.

[0386] Further, the present invention provides a pattern forming method, which is a method for forming a pattern on a substrate to be processed, and has the following steps:

[0387] (III-1) After coating the above composition for forming a metal oxide film on the substrate to be processed, heat treatment is performed to form a metal oxide film.

[0388] (III-2) An inorganic hard mask intermediate film selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film is formed on the metal oxide film.

[0389] (III-3) An organic film is formed on the inorganic hard mask intermediate film.

[0390] (III-4) A resist upper film is formed on the organic film using a photoresist material.

[0391] (III-5) After pattern exposure of the resist upper film, development is performed with a developer to form a pattern on the resist upper film.

[0392] (III-6) The patterned resist upper film is used as a mask, and the pattern is transferred to the organic film and the inorganic hard mask intermediate film by dry etching.

[0393] (III-7) The patterned inorganic hard mask intermediate film is used as a mask, and the pattern is transferred to the metal oxide film by dry etching, and

[0394] (III-8) The patterned metal oxide film is used as a mask, and the substrate to be processed is processed to form a pattern on the substrate to be processed.

[0395] In this case, it is preferable to form the above inorganic hard mask by CVD method or ALD method.

[0396] If the above inorganic hard mask is formed by CVD method or ALD method, a fine pattern can be formed on the object to be processed with higher precision.

[0397] As described above, when forming an inorganic hard mask on a metal oxide film, a silicon oxide film, a silicon nitride film, and a silicon oxynitride film (SiON film) can be formed by a CVD method, an ALD method, etc. For example, a method for forming a silicon nitride film is described in Japanese Patent Laid-Open No. 2002-334869 and International Publication No. 2004 / 066377. The film thickness of the inorganic hard mask is preferably 5 to 200 nm, more preferably 10 to 100 nm. Also, it is most ideal to use a SiON film having a high effect as an antireflection film for the inorganic hard mask. Since the substrate temperature when forming the SiON film becomes 300 to 500 °C, the metal oxide film needs to be able to withstand a temperature of 300 to 500 °C. The composition for forming a metal oxide film used in the present invention has high heat resistance and can withstand a high temperature of 300 °C to 500 °C, so it can be a combination of an inorganic hard mask formed by a CVD method or an ALD method and a metal oxide film formed by a spin coating method.

[0398] As described above, a photoresist film can also be formed as an upper resist film on the inorganic hard mask, but an organic antireflection film (BARC) or a spacer film can also be spin-coated on the inorganic hard mask, and a photoresist film can be formed thereon. In particular, when using a SiON film as the inorganic hard mask, by using a two-layer antireflection film of SiON film and BARC, reflection can be suppressed even in immersion exposure with a high NA exceeding 1.0. Another advantage of forming the BARC is that it has an effect of reducing the tailing of the photoresist pattern directly above the SiON film.

[0399] The upper resist film of the three-layer resist process described above can be either positive or negative, and the same as the commonly used photoresist composition can be used. After spin-coating the photoresist composition, pre-baking is performed, but it is preferably in the range of 60 to 180 °C for 10 to 300 seconds. Thereafter, exposure is performed in the usual manner, and then post-exposure baking (PEB) and development are performed to obtain a resist pattern. Also, the thickness of the upper resist film is not particularly limited, preferably 30 to 500 nm, more preferably 50 to 400 nm.

[0400] Also, the exposure light can include high-energy rays having a wavelength of 300 nm or less. Specifically, for example, excimer lasers of 248 nm, 193 nm, and 157 nm, soft X-rays of 3 to 20 nm, electron beams, X-rays, etc.

[0401] If the above method is used as a method for forming a circuit pattern on the above upper resist film, a fine pattern can be formed on the workpiece with higher precision.

[0402] The method for forming a pattern of the above upper resist film is preferably to form a pattern by using optical lithography having a wavelength of 5 nm or more and 300 nm or less, direct drawing using an electron beam, nanoimprinting, or a combination thereof.

[0403] Further, the development method of the above-described pattern formation method is preferably alkali development or development using an organic solvent. Specifically, in the above-described pattern formation method, in order to form a circuit pattern on the upper resist film, exposure and development are performed, and the aforementioned development is preferably alkali development or development using an organic solvent.

[0404] If alkali development or development using an organic solvent is used as the development method, a fine pattern can be formed with higher precision on the object to be processed.

[0405] Then, the obtained resist pattern is used as a mask for etching. For the etching of the silicon-containing resist intermediate film and the inorganic hard mask in the three-layer resist process, a fluorocarbon-based gas is used, and the upper resist pattern is used as a mask. Thereby, a silicon-containing resist intermediate film pattern and an inorganic hard mask pattern are formed.

[0406] Next, using the obtained silicon-containing resist intermediate film pattern and inorganic hard mask pattern as masks, etching of the metal oxide film is performed. It is preferable to use a chlorine-based gas for the etching of the metal oxide film.

[0407] The subsequent etching of the object to be processed can be carried out by a conventional method. For example, if the object to be processed is SiO 2 , SiN, or a silicon dioxide-based low dielectric constant insulating film, etching mainly using a chlorofluorocarbon-based gas is performed. When etching the substrate using a chlorofluorocarbon-based gas, the silicon-containing resist intermediate film pattern in the three-layer resist process is peeled off simultaneously during the substrate processing.

[0408] The metal oxide film obtained using the composition for forming a metal oxide film of the present invention has the characteristic of excellent etching resistance during the etching of these objects to be processed.

[0409] Further, the object to be processed (substrate to be processed) is not particularly limited, and substrates such as Si, α-Si, p-Si, SiO 2 , SiN, SiON, W, TiN, Al, etc., and substrates on which a processed layer has been formed on the substrate can be used. As the processed layer, various Low-k films such as Si, SiO 2 , SiON, SiN, p-Si, α-Si, W, W-Si, Al, Cu, Al-Si, and their barrier films can be used, and they can usually be formed with a thickness of 50 to 10,000 nm, particularly 100 to 5,000 nm. Further, when forming the processed layer, different materials are used for the substrate and the processed layer.

[0410] The work piece preferably uses a semiconductor device substrate, or a substrate on which any one of a metal film, a metal carbide film, a metal oxide film, a metal nitride film, a metal oxycarbide film, and a metal oxynitride film is formed. More specifically, without particular limitation, Si, α-Si, p-Si, SiO 2 , SiN, SiON, W, TiN, Al and other substrates, and those on which the above metal films and the like have been formed as the processed layer, etc.

[0411] The processed layer can use various Low-k films such as Si, SiO 2 , SiON, SiN, p-Si, α-Si, W, W-Si, Al, Cu, Al-Si and their barrier films, and can usually be formed with a thickness of 50 to 10,000 nm, especially 100 to 5,000 nm. Also, when forming the processed layer, substrates and processed layers of different materials are used.

[0412] Also, the metal constituting the work piece is preferably silicon, titanium, tungsten, hafnium, zirconium, chromium, germanium, copper, silver, gold, aluminum, indium, gallium, arsenic, palladium, iron, tantalum, iridium, cobalt, manganese, molybdenum, ruthenium, or an alloy of these.

[0413] These metals can be used as the above metals. Thus, if a pattern is formed using the composition for forming a metal oxide film of the present invention, the pattern of the upper photoresist can be transferred and formed on the work piece with high precision.

[0414] The pattern formation method of the present invention preferably uses a work piece substrate having a structure or height difference with an aspect ratio of 5 or more. As described above, the composition for forming a metal oxide film of the present invention has excellent filling / planarizing characteristics. Therefore, even if the work piece substrate has a structure or height difference (concavity and convexity) with an aspect ratio of 5 or more, it can be filled without pores, and a flat hardened film can be formed. It is more ideal that the aspect ratio of the structure or height difference of the above work piece substrate is 5 or more, and more preferably 10 or more. In the processing method of the work piece substrate having the structure or height difference with an aspect ratio, by forming the composition for forming a metal oxide film of the present invention and performing filling / planarizing, the film thicknesses of the resist intermediate film and the resist upper film formed thereafter can be uniform, so it is easy to ensure the exposure depth tolerance (DOF) during optical lithography, which is very ideal.

[0415] Also, in the present invention, regarding the tone inversion type pattern formation method using such a composition for forming a metal oxide film, a pattern formation method is provided, which is a method for forming a pattern on a work piece substrate and has the following steps:

[0416] (IV-1) Forming a resist lower layer film on the work piece substrate,

[0417] (IV-2) An antireflective intermediate film, or a combination of an inorganic hard mask intermediate film selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film and an organic thin film, is formed on the foregoing antireflective lower film.

[0418] (IV-3) An antireflective upper film is formed on the foregoing antireflective intermediate film, or the combination of the inorganic hard mask intermediate film and the organic thin film, using a photoresist material.

[0419] (IV-4) After the foregoing antireflective upper film is pattern-exposed, it is developed with a developer to form a pattern on the foregoing antireflective upper film.

[0420] (IV-5) Using the foregoing patterned antireflective upper film as a mask, the pattern is transferred to the foregoing antireflective intermediate film, or the foregoing organic thin film and the foregoing inorganic hard mask intermediate film, by dry etching.

[0421] (IV-6) Using the foregoing patterned antireflective intermediate film, or the inorganic hard mask intermediate film, as a mask, the pattern is transferred to the foregoing antireflective lower film by dry etching.

[0422] (IV-7) After the foregoing composition for forming a metal oxide film is coated on the foregoing patterned antireflective lower film, heat treatment is performed to coat a metal oxide film, and the spaces between the patterns of the foregoing antireflective lower film are filled with the foregoing metal oxide film.

[0423] (IV-8) The foregoing metal oxide film coated on the foregoing patterned antireflective lower film is etched back by chemical stripping or dry etching to expose the top surface of the patterned antireflective lower film.

[0424] (IV-9) The remaining antireflective intermediate film, or the inorganic hard mask intermediate film, on the top surface of the foregoing antireflective lower film is removed by dry etching.

[0425] (IV-10) The foregoing patterned antireflective lower film with the surface exposed is removed by dry etching to form an inverted pattern of the original pattern on the metal oxide film.

[0426] (IV-11) Using the foregoing metal oxide film with the inverted pattern formed thereon as a mask, the foregoing substrate to be processed is processed to form a tone-inverted pattern on the foregoing substrate to be processed.

[0427] For an example of the formation of a tone-inverted pattern, if Figure 2 is specifically disclosed as follows. As Figure 2 shown in (G), after an antireflective lower film 7 made of a coating-type organic lower film material is formed on a processed layer 2 laminated on a substrate to be processed 1, an antireflective intermediate film 4 containing silicon atoms is formed, and an antireflective upper film 5 is formed thereon.

[0428] Next, as shown in (H) of Figure 2 , the used portion (exposed portion) 6 of the upper resist film 5 is exposed, and PEB and development are performed to form an upper resist film pattern 5a ( Figure 2 in (I)). Using the obtained upper resist film pattern 5a as a mask, the resist intermediate film 4 containing silicon atoms is etched using a CF-based gas to form a resist intermediate film pattern 4a containing silicon atoms ( Figure 2 in (J)). After removing the upper resist film pattern 5a, using the obtained resist intermediate film pattern 4a containing silicon atoms as a mask, the lower resist film 7 made of a coating-type organic lower film material is subjected to oxygen plasma etching to form a lower resist film pattern 7a made of a coating-type organic lower film material ( Figure 2 in (K)).

[0429] After coating the composition for forming a metal oxide film of the present invention on the lower resist film pattern 7a made of a coating-type organic lower film material, the metal oxide film 8 is formed by heat treatment, and the space between the lower resist film patterns 7a made of a coating-type organic lower film material is filled with the metal oxide film ( Figure 2 in (L)). Then, the metal oxide film 8 covering the lower resist film pattern 7a made of a coating-type organic lower film material is etched back using chemical stripping or dry etching to expose the top surface of the lower resist film pattern 7a made of a coating-type organic lower film material, and a metal oxide film pattern 8a formed by inverting the lower resist film pattern remains between the lower resist film patterns 7a made of a coating-type organic lower film material ( Figure 2 in (M)). Next, the resist intermediate film pattern 4a containing silicon atoms remaining on the top surface of the lower resist film pattern 7a made of a coating-type organic lower film material is removed by dry etching ( Figure 2 in (N)). Then, the lower resist film pattern 7a made of a coating-type organic lower film material is removed by dry etching, and after the step of forming an inverted pattern of the original pattern on the metal oxide film (forming a metal oxide film pattern 8a formed by inverting the lower resist film pattern) ( Figure 2 in (O)), the metal oxide film pattern 8a formed by inverting the lower resist film pattern is used as a mask to process the aforementioned substrate to be processed, and a tone-inverted pattern 2a is formed on the aforementioned substrate to be processed ( Figure 2 in (P)).

[0430] As described above, when forming an organic resist underlayer film on a substrate to be processed, the organic resist underlayer film can be formed by a method using a coating-type organic underlayer film material, a CVD method, or the like. Examples of the coating-type organic underlayer film material include resins and compositions disclosed in Japanese Patent Application Laid-Open Nos. 2012-1687, 2012-77295, 2004-264710, 2005-043471, 2005-250434, 2007-293294, 2008-65303, 2004-205685, 2007-171895, 2009-14816, 2007-199653, 2008-274250, 2010-122656, 2012-214720, 2014-29435, International Publication Nos. WO2012 / 077640, WO2010 / 147155, WO2012 / 176767, Japanese Patent Application Laid-Open Nos. 2005-128509, 2006-259249, 2006-259482, 2006-293298, 2007-316282, 2012-145897, 2017-119671, 2019-44022, etc. The organic resist underlayer film formed by the CVD method is, for example, an amorphous carbon film.

[0431] In the above-described tone inversion type pattern forming method, after coating the obtained resist underlayer film pattern with a composition for forming a metal oxide film, in order to expose the top surface of the resist underlayer film pattern, it is preferably to remove the metal oxide film by dry etching using a chlorine-based gas. Thereafter, the resist intermediate film or the hard mask intermediate film remaining on the resist underlayer film is removed by dry etching using a chlorofluorocarbon-based gas, and the exposed resist underlayer film pattern on the surface is removed by dry etching using an oxygen-based gas to form a metal oxide film pattern.

[0432] In the above-described tone inversion type pattern forming method, it is preferable to use a work substrate having a structure or height difference with an aspect ratio of 5 or more. As described above, the composition for forming a metal oxide film of the present invention has excellent filling / planarizing characteristics, so that even if there is a structure or height difference (concavo-convex) with an aspect ratio of 5 or more, a flat cured film can be formed. It is more desirable that the aspect ratio of the structure or height difference of the work substrate is 5 or more, more preferably 50 nm or more, and still more preferably 100 nm or more. In the method of inverting the resist underlayer film pattern of the pattern having the above height, by forming the composition for forming a metal oxide film of the present invention and performing filling / planarization, pattern inversion / transfer can be performed with high precision, which is very desirable. Compared with a resist underlayer film using a known coating type organic underlayer film material, it has excellent dry etching resistance using a chlorofluorocarbon-based gas. By inverting the resist underlayer film pattern with the above-described composition for forming a metal oxide film, it is possible to form a desired resist pattern with high precision on the work film, which is an advantage.

[0433] In the above-described two-layer resist pattern forming method, three-layer resist pattern forming method, four-layer resist pattern forming method, and tone inversion type pattern forming method of the present invention, it is preferable to form a pattern with an aspect ratio of 5 or more on the above-described work substrate. As described above, the composition for forming a metal oxide film of the present invention can form a metal oxide film with excellent dry etching resistance in a thick film, so that a high aspect ratio pattern can be transferred to the work substrate with high precision. The aspect ratio of the pattern formed on the work substrate using the above-described metal oxide film as a hard mask is preferably 5 or more, and more preferably 10 or more. In order to transfer a high aspect ratio pattern with high precision, the hard mask requires an expanded thick film forming tolerance and excellent dry etching resistance. The composition for forming a metal oxide film of the present invention can form a metal oxide film with a thickness of 1 μm or more by using a fluidity promoter with excellent cracking resistance.

[0434] Furthermore, the present invention provides a pattern forming method, which is a pattern forming method using a composition for forming a metal oxide film on a sacrificial film, and includes the following steps:

[0435] (V-1) After coating the above-described composition for forming a metal oxide film on a work substrate having a structure or height difference, heat treatment is performed to fill the metal oxide film.

[0436] (V-2) The metal oxide film outside the structure or height difference on the work substrate is removed by CMP method, and the metal oxide film is removed from the surface of the work substrate.

[0437] (V-3) An insulating film and a conductive film are alternately laminated on the work substrate filled with the metal oxide film.

[0438] (V-4) An organic resist underlayer film is formed on a stacked film of an insulating film and a conductive film formed on a processed substrate filled with the metal oxide film.

[0439] (V-5) A resist intermediate film, an inorganic hard mask intermediate film selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film, or a combination of the inorganic hard mask intermediate film and an organic thin film is formed on the organic resist underlayer film.

[0440] (V-6) On the resist intermediate film, the inorganic hard mask intermediate film, or the combination of the inorganic hard mask intermediate film and the organic thin film, a resist upper layer film is formed using a photoresist material.

[0441] (V-7) After the resist upper layer film is pattern-exposed, it is developed with a developer to form a pattern on the resist upper layer film.

[0442] (V-8) Using the patterned resist upper layer film as a mask, the pattern is transferred to the resist intermediate film, the inorganic hard mask intermediate film, or the organic thin film and the inorganic hard mask intermediate film by dry etching.

[0443] (V-9) Using the patterned resist intermediate film or inorganic hard mask intermediate film as a mask, the pattern is transferred to the resist underlayer film by dry etching.

[0444] (V-10) Using the patterned resist underlayer film as a mask, the pattern is transferred to the stacked film of the insulating film and the conductive film by dry etching.

[0445] (V-11) Using the patterned stacked film of the insulating film and the conductive film as a mask, the metal oxide film filled on the processed substrate is removed.

[0446] Regarding an example of the pattern formation method using the metal oxide film-forming composition for use on a sacrificial film, use Figure 3 is specifically disclosed as follows. As Figure 3 shown in (Q), the insulating film pattern 10a and the conductive film pattern 9a are alternately stacked, and after coating the composition for forming a metal oxide film of the present invention on the height difference formed in the alternately stacked film (lower layer) 100 of the insulating film pattern 10a and the conductive film pattern 9a containing the upper and lower continuous insulating film 11, heat treatment is performed to coat the metal oxide film 12 ( Figure 3 in (R)), the aforementioned metal oxide film 12 located outside the height difference is removed by CMP method, and the metal oxide film 12 is removed from the surface of the processed substrate to be flattened ( Figure 3 in (S)). The metal oxide film located outside the height difference is removed by the aforementioned CMP planarization, and then, an alternately stacked film (upper layer) 200 of the insulating film 10 and the conductive film 9 is formed ( Figure 3(T)), an organic resist lower layer film 13 is formed on the above-mentioned alternating laminated film, and a resist intermediate film 14 containing silicon atoms is formed on the organic resist lower layer film 13 (forming a polysiloxane-based 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, or a combination of the aforementioned inorganic hard mask intermediate film and an organic thin film), and a resist upper layer film 15 is formed on the resist intermediate film 14( Figure 3 (U)).

[0447] Next, the resist upper layer film 15 is exposed, and PEB and development are performed to form a resist upper layer film pattern 15a( Figure 3 (V)). Using the obtained resist upper layer film pattern 15a as a mask, the resist intermediate film 14 containing silicon atoms is etched using a CF-based gas to form a resist intermediate film pattern 14a containing silicon atoms( Figure 3 (W)). After removing the resist upper layer film pattern 15a, using the obtained resist intermediate film pattern 14a containing silicon atoms as a mask, the organic resist lower layer film 13 is subjected to oxygen plasma etching to form an organic resist lower layer film pattern 13a( Figure 3 (X)). Using the resist lower layer film pattern 13a as a mask, the alternating laminated film (upper layer) 200 of the insulating film 10 and the conductive film 9 is dry-etched using a CF-based gas to form a high aspect ratio pattern( Figure 3 (Y)). After that, the metal oxide film 12a after CMP planarization filling the height difference of the processed layer 100 is removed by dry etching using a chlorine-based gas, so that the pattern formed on the laminated film 200 and the pattern 16 formed on the alternating laminated film (lower layer) 100 of the insulating film pattern 10 and the conductive film pattern 9a (forming a through pattern 16 of the 100th layer and the 200th layer) are penetrated( Figure 3 (Z)).

[0448] The laminated film 100 of the insulating film pattern 10a and the conductive film pattern 9a, and the above-mentioned alternating laminated film 200 of the insulating film 10 and the conductive film 9 are deposited on the substrate using a deposition precursor suitable for the CVD method or the atomic layer volume method (ALD). The above-mentioned insulating film pattern 10a and insulating film 10 can be formed using any appropriate (multiple) insulating materials. For example, without limitation, the insulating material may contain silicon oxide (for example: SiO 2 ). The conductive film pattern 9a and conductive film 9 can be formed from any appropriate (multiple) conductive materials. It may contain polysilicon, and one or more of tungsten, nickel, titanium, platinum, aluminum, gold, tungsten nitride, tantalum nitride, titanium nitride, silicon nitride and other metals.

[0449] As described above, when forming the organic resist underlayer film 13 on the alternating laminated film 200 of the insulating film 10 and the conductive film 9, the organic resist underlayer film can be formed by a method using a coating-type organic underlayer film material, a CVD method, or the like. Examples of the coating-type organic underlayer film material include those disclosed in JP-A-2012-1687, JP-A-2012-77295, JP-A-2004-264710, JP-A-2005-043471, JP-A-2005-250434, JP-A-2007-293294, JP-A-2008-65303, JP-A-2004-205685, JP-A-2007-171895, JP-A-2009-14816, JP-A-2007-199653, JP-A-2008-274250, JP-A-2010-122656, JP-A-2012-214720, JP-A-2014-29435, International Publication WO2012 / 077640, International Publication WO2010 / 147155, International Publication WO2012 / 176767, JP-A-2005-128509, JP-A-2006-259249, JP-A-2006-259482, JP-A-2006-293298, JP-A-2007-316282, JP-A-2012-145897, JP-A-2017-119671, JP-A-2019-44022, etc. Further, the organic resist underlayer film may be one containing metal atoms of zirconium, hafnium, aluminum, tungsten, titanium, copper, tin, cerium, indium, zinc, yttrium, lanthanum, chromium, cobalt, platinum, iron, antimony, and germanium, or a combination thereof, and the composition for forming the metal oxide film of the present invention may also be used.

[0450] The organic resist underlayer film formed by the CVD method contains, for example, an amorphous carbon film or a doped carbon film containing metal atoms of zirconium, hafnium, aluminum, tungsten, titanium, copper, tin, cerium, indium, zinc, yttrium, lanthanum, chromium, cobalt, platinum, iron, antimony, and germanium, or a combination thereof.

[0451] Regarding the height difference formed by the alternating stacked film 100 of the above-mentioned insulating film pattern 10a and conductive film pattern 9a, it is preferably to form a pattern with an aspect ratio of 5 or more. As described above, the composition for forming a metal oxide film of the present invention has excellent filling / planarization characteristics. Therefore, even when the substrate to be processed has a structure or height difference (concave and convex) with an aspect ratio of 5 or more, it can be filled without pores and a flat hardened film can be formed. It is more ideal that the aspect ratio of the structure or height difference possessed by the substrate to be processed is 5 or more, more preferably 10 or more, still more preferably 20 or more, and particularly preferably 50 or more. In the method of filling the substrate to be processed with a structure or height difference having the above aspect ratio, by forming and filling / planarizing the composition for forming a metal oxide film of the present invention, the film thickness of the alternating layers of the insulating film and conductive film formed later, and the photoresist formed on the above alternating layers can be uniform. Therefore, it is easy to ensure the exposure depth tolerance (DOF) during optical lithography, which is very ideal during the multi-stack manufacturing process of 3D-NAND. Also, the composition for forming a metal oxide film of the present invention has excellent heat resistance. Therefore, even after the process of forming the alternating layers of the insulating film and conductive film on the substrate to be processed filled with the metal oxide film, no pores or peeling occur in the filled film, and a high aspect ratio pattern can be formed with high precision.

[0452] The thickness of the above-mentioned organic resist underlayer film 13 can be determined in consideration of the thickness of the alternating stacked film 200 of the above-mentioned insulating film 10 and conductive film 9 of the film to be etched. For example, it can be formed with a thickness of 10,000 to 100,000 angstroms.

[0453] The resist upper layer film for the above-mentioned multi-layer resist treatment can be either positive or negative, and the same as the commonly used photoresist composition can be used. After spin-coating the photoresist composition, pre-baking is performed, and it is preferably in the range of 60 to 180 °C for 10 to 300 seconds. Then, exposure is performed according to the usual method, and furthermore, post-exposure baking (PEB) and development are performed to obtain a resist pattern. Also, the thickness of the resist upper layer film is not particularly limited, and it is more ideal to be 30 to 1,000 nm, and particularly preferably 50 to 500 nm.

[0454] Also, the exposure light is high-energy rays with a wavelength of 300 nm or less. Specifically, for example, excimer lasers of 248 nm, 193 nm, 157 nm, soft X-rays of 3 to 20 nm, electron beams, X-rays, etc.

[0455] If the above method is used as the method for forming a circuit pattern on the above-mentioned resist upper layer film, then a finer pattern can be formed on the substrate to be processed with higher precision.

[0456] The method for forming a pattern on the above-mentioned resist upper layer film is preferably to form a pattern by optical lithography with a wavelength of 5 nm or more and 300 nm or less, direct drawing using an electron beam, nanoimprinting, or a combination of these.

[0457] Furthermore, in the above-described pattern formation method, the development method is preferably alkali development or development using an organic solvent. Specifically, in the above-described pattern formation method, in order to form a circuit pattern on the upper layer of the resist, exposure and development are performed, and the above-mentioned development is preferably alkali development or development using an organic solvent.

[0458] Regarding the development method, if alkali development or development using an organic solvent is used, a fine pattern can be formed on the workpiece with higher precision.

[0459] (Method for forming metal oxide film)

[0460] The present invention provides a method for forming an underlayer resist film for a multilayer resist film used in lithography or a filling film serving as a planarization film (organic planar film) for semiconductor manufacturing using the above-described composition for forming a metal oxide film.

[0461] Specifically, a method for forming a metal oxide film is provided, which is a method for forming a metal oxide film serving as a planarization film in the manufacturing process of a semiconductor device. By heat-treating a substrate coated with the above-described composition for forming a metal oxide film on a workpiece substrate at a temperature of 100°C or higher and 600°C or lower for a range of 10 to 600 seconds, a hardened film is formed.

[0462] Furthermore, a method for forming a metal oxide film is provided, which is a method for forming a metal oxide film serving as a planarization film in the manufacturing process of a semiconductor device. By heat-treating a substrate coated with the above-described composition for forming a metal oxide film on a workpiece substrate in a gas environment with an oxygen concentration of 1% by volume or higher and 21% by volume or lower, a hardened film is formed.

[0463] Furthermore, a method for forming a metal oxide film is provided, which is a method for forming a metal oxide film serving as a planarization film in the manufacturing process of a semiconductor device. By heat-treating a substrate coated with the above-described composition for forming a metal oxide film on a workpiece substrate in a gas environment with an oxygen concentration of less than 1% by volume, a hardened film is formed.

[0464] According to such a method, even when the workpiece substrate contains a material that is unstable to heating in an oxygen environment, deterioration of the workpiece substrate will not occur, and the crosslinking reaction of the above-described composition for forming a metal oxide film during the formation of the metal oxide film is promoted, and mixing with the upper layer film can be suppressed to a greater extent, which is useful.

[0465] The method for forming a metal oxide film using the composition for forming a metal oxide film of the present invention is to coat the above-described composition for forming a metal oxide film on a substrate to be processed by a spin coating method (spin coating) or the like. By using a spin coating method or the like, good filling characteristics can be obtained. After spin coating, baking (heat treatment) is performed in order to evaporate the solvent and prevent mixing with the upper resist film and the intermediate resist film, and to promote the crosslinking reaction. The baking is preferably performed in the range of 100°C or higher and 600°C or lower for 10 to 600 seconds, more preferably in the range of 200°C or higher and 500°C or lower for 10 to 300 seconds. Considering device damage and the influence on wafer deformation, the upper limit of the heating temperature for wafer processing in lithography is preferably set to 600°C or lower, more preferably 500°C or lower.

[0466] Furthermore, in the method for forming a metal oxide film using the composition for forming a metal oxide film of the present invention, the composition for forming a metal oxide film of the present invention and the above can be coated on a substrate to be processed by a spin coating method or the like, and the composition for forming a metal oxide film is calcined in a gas environment with an oxygen concentration of 0.1% by volume or higher and 21% by volume or lower to be hardened to form a metal oxide film.

[0467] By calcining the composition for forming a metal oxide film of the present invention in such an oxygen environment, a sufficiently hardened film can be obtained. The gas environment during baking may be air. In order to reduce oxygen, an inert gas such as N 2 , Ar, or He is preferably sealed in advance to prevent oxidation of the metal oxide film, which is ideal. In order to prevent oxidation, it is necessary to control the oxygen concentration, preferably 1000 ppm or lower, more preferably 100 ppm or lower (volume basis). If oxidation of the metal oxide film during baking is prevented, there will be no increase in absorption or decrease in etching resistance, which is ideal.

[0468] Examples

[0469] Synthesis examples, examples, and comparative examples are given below for a more specific description of the present invention, but the present invention is not limited to these. Furthermore, the molecular weight and dispersity are obtained by measuring the weight average molecular weight (Mw) and number average molecular weight (Mn) in terms of polystyrene measured by gel permeation chromatography (GPC) using tetrahydrofuran as an eluent, and the dispersity (Mw / Mn) is calculated.

[0470] The resins (B-1) to (B-6) for the resist underlayer film material are synthesized using the resin raw materials (b-1) to (b-6) shown below, and (B-7) to (B-8) are synthesized using the resin (B-4). The resin (R-1) for the comparative example is synthesized using the resin (B-3), the resin (R-3) for the comparative example is synthesized using the raw material (G-1) of the comparative example resin, and the resin (R-4) for the comparative example is synthesized using the raw material (G-2) of the comparative example resin, and the reaction rate is controlled by using the modifiers (c-1) to (c-2) for synthesis.

[0471] Resin raw materials:

[0472] [Chemical formula 44]

[0473]

[0474] Resin used as an intermediate:

[0475] [Chemical formula 45]

[0476]

[0477] Raw materials for the comparative example resin:

[0478] [Chemical formula 46]

[0479]

[0480] Modifier:

[0481] [Chemical formula 47]

[0482]

[0483] The resins (B-1) to (B-6) shown above are synthesized in the following manner.

[0484] (Synthesis Example 1)

[0485] Synthesis of resin (B-1)

[0486] [Chemical formula 48]

[0487]

[0488] Under a nitrogen atmosphere, 188.2 g of the resin raw material (b-1), 113.6 g of the resin raw material (b-5), 9.0 g of oxalic acid, and 100 g of dioxane were added, and the reaction was carried out at an internal temperature of 100 °C for 24 hours. After the reaction was completed, it was cooled to room temperature, 2,000 ml of MIBK was added, and it was washed 6 times with 500 ml of pure water. The organic layer was recovered, and the pressure was reduced to 2 mmHg at an internal temperature of 150 °C, and water, solvent, and residual monomers were removed under reduced pressure to obtain the resin (B-1).

[0489] The weight-average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the results are as follows.

[0490] (B-1): Mw = 6,500, Mw / Mn = 2.87

[0491] (Synthesis Example 2)

[0492] Synthesis of Resin (B-2)

[0493] [Chemical Formula 49]

[0494]

[0495] Under a nitrogen atmosphere, 94.1 g of resin raw material (b-1), 89.8 g of resin raw material (b-6), and 400 g of dichloromethane were added, and a homogeneous dispersion was prepared at an internal temperature of 30°C. Then, 211 g of methanesulfonic acid was added over 2 hours, and the reaction was carried out at an internal temperature of 30°C for 24 hours. After the reaction was completed, it was cooled to room temperature, 2,000 ml of MIBK was added, and it was washed 6 times with 500 ml of pure water. The organic layer was dried under reduced pressure. 300 g of THF was added to the residue to form a homogeneous solution, and then it was crystallized in 2,000 g of hexane. The precipitated crystals were separated by filtration, washed 2 times with 500 g of hexane and recovered. The recovered crystals were dried in vacuo at 70°C to obtain Resin (B-2).

[0496] The weight-average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the results are as follows.

[0497] (B-2): Mw = 6,300, Mw / Mn = 3.11

[0498] (Synthesis Example 3)

[0499] Synthesis of Resin (B-3)

[0500] [Chemical Formula 50]

[0501]

[0502] Under a nitrogen atmosphere, 216.3 g of resin raw material (b-2), 113.6 g of resin raw material (b-5), 10.8 g of oxalic acid, and 200 g of dioxane were added, and the reaction was carried out at an internal temperature of 100°C for 24 hours. After the reaction was completed, it was cooled to room temperature, 2,000 ml of MIBK was added, and it was washed 6 times with 500 ml of pure water. The organic layer was recovered, and the pressure was reduced to 2 mmHg at an internal temperature of 150°C to remove water, solvent, and residual monomers under reduced pressure to obtain Resin (B-3).

[0503] The weight-average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the results are as follows.

[0504] (B-3): Mw = 7,000, Mw / Mn = 3.50

[0505] (Synthesis Example 4)

[0506] Synthesis of Resin (B-4)

[0507] [Chemical Formula 51]

[0508]

[0509] Under a nitrogen atmosphere, 108.2 g of resin raw material (b-2), 89.8 g of resin raw material (b-6), and 400 g of dichloromethane were added to obtain a homogeneous dispersion at an internal temperature of 30°C. Subsequently, 211 g of methanesulfonic acid was added over 2 hours, and the reaction was carried out at an internal temperature of 30°C for 24 hours. After the reaction was completed, it was cooled to room temperature, 2,000 ml of MIBK was added, and it was washed 6 times with 500 ml of pure water, and the organic layer was dried under reduced pressure. 300 g of THF was added to the residue to form a homogeneous solution, and then crystallized in 2,000 g of hexane. The precipitated crystals were separated by filtration, washed 2 times with 500 g of hexane and recovered. The recovered crystals were dried in vacuo at 70°C to obtain Resin (B-4).

[0510] The weight-average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the results were as follows.

[0511] (B-4): Mw = 6,900, Mw / Mn = 3.34

[0512] (Synthesis Example 5)

[0513] Synthesis of Resin (B-5)

[0514] [Chemical Formula 52]

[0515]

[0516] Under a nitrogen atmosphere, 144.2 g of resin raw material (b-3), 56.8 g of resin raw material (b-5), and 300 g of PGME (propylene glycol monomethyl ether) were added to homogenize at an internal temperature of 100°C. Subsequently, a mixed solution of 7.1 g of p-toluenesulfonic acid monohydrate and 7.1 g of PGME, which had been previously mixed and homogenized, was slowly added dropwise, and the reaction was carried out at an internal temperature of 100°C for 8 hours. After the reaction was completed, it was cooled to room temperature, 2,000 ml of MIBK was added, and it was washed 6 times with 500 ml of pure water, and the organic layer was dried under reduced pressure. 300 g of THF was added to the residue to form a homogeneous solution, and then crystallized in 2,000 g of hexane. The precipitated crystals were separated by filtration, washed 2 times with 500 g of hexane and recovered. The recovered crystals were dried in vacuo at 70°C to obtain Resin (B-5).

[0517] The weight-average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the results are as follows.

[0518] (B-5): Mw = 2,900, Mw / Mn = 2.76

[0519] (Synthesis Example 6)

[0520] Synthesis of Resin (B-6)

[0521] [Chemical Formula 53]

[0522]

[0523] Under a nitrogen atmosphere, 160.2 g of resin raw material (b-4), 56.8 g of resin raw material (b-5), and 300 g of PGME (propylene glycol monomethyl ether) were added and homogenized at an internal temperature of 100 °C. Subsequently, a mixed solution of 8.0 g of p-toluenesulfonic acid monohydrate and 8.0 g of PGME, which had been previously mixed and homogenized, was slowly added dropwise, and the reaction was carried out at an internal temperature of 80 °C for 8 hours. After the reaction was completed, it was cooled to room temperature, 2,000 ml of MIBK was added, and it was washed 6 times with 500 ml of pure water. The organic layer was dried under reduced pressure. 300 g of THF was added to the residue to form a homogeneous solution, and then it was crystallized in 2,000 g of hexane. The precipitated crystals were separated by filtration, washed 2 times with 500 g of hexane, and recovered. The recovered crystals were dried in vacuo at 70 °C to obtain Resin (B-6).

[0524] The weight-average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the results are as follows.

[0525] (B-6): Mw = 3,300, Mw / Mn = 2.54

[0526] (Synthesis Example 7)

[0527] Synthesis of Resin (B-7)

[0528] [Chemical Formula 54]

[0529]

[0530] Under a nitrogen atmosphere, 20.0 g of Resin (B-4), 15.8 g of potassium carbonate, and 100 g of DMF were added to form a homogeneous dispersion at an internal temperature of 50 °C. 7.9 g of modifier (c-1) was slowly added, and the reaction was carried out at an internal temperature of 50 °C for 24 hours. 300 ml of methyl isobutyl ketone and 300 g of pure water were added to the reaction solution to dissolve the precipitated salt, and then the separated aqueous layer was removed. The organic layer was washed 6 times with 100 g of 3% nitric acid aqueous solution and 100 g of pure water, and then the organic layer was dried under reduced pressure to obtain Resin (B-7).

[0531] The weight-average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the results are as follows.

[0532] (B-7): Mw = 7,700, Mw / Mn = 3.35

[0533] (Synthesis Example 8)

[0534] Synthesis of Resin (B-8)

[0535] [Chemical Formula 55]

[0536]

[0537] Under a nitrogen atmosphere, 20.0 g of Resin (B-4), 15.8 g of potassium carbonate, and 100 g of DMF were added, and a homogeneous dispersion was prepared at an internal temperature of 50°C. 8.1 g of the modifier (c-2) was slowly added, and the reaction was carried out at an internal temperature of 50°C for 24 hours. 300 ml of methyl isobutyl ketone and 300 g of pure water were added to the reaction solution to dissolve the precipitated salt, and then the separated aqueous layer was removed. The organic layer was washed 6 times with 100 g of 3% nitric acid aqueous solution and 100 g of pure water, and then the organic layer was dried under reduced pressure to obtain Resin (B-8).

[0538] The weight-average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the results are as follows.

[0539] (B-8): Mw = 7,500, Mw / Mn = 3.37

[0540] (Synthesis Example 9)

[0541] Synthesis of Resin (R-1)

[0542] [Chemical Formula 56]

[0543]

[0544] Under a nitrogen atmosphere, 20.0 g of Resin (B-3), 34.5 g of potassium carbonate, and 100 g of DMF were added, and a homogeneous dispersion was prepared at an internal temperature of 50°C. 23.8 g of the modifier (c-1) was slowly added, and the reaction was carried out at an internal temperature of 50°C for 24 hours. 300 ml of methyl isobutyl ketone and 300 g of pure water were added to the reaction solution to dissolve the precipitated salt, and then the separated aqueous layer was removed. The organic layer was washed 6 times with 100 g of 3% nitric acid aqueous solution and 100 g of pure water, and then the organic layer was dried under reduced pressure to obtain Resin (R-1).

[0545] The weight-average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the results are as follows.

[0546] (R-1): Mw = 9,400, Mw / Mn = 3.59

[0547] (Synthesis Example 10)

[0548] Synthesis of Resin (R-2)

[0549] [Chemical Formula 57]

[0550]

[0551] 23.3 g of PGMEA was heated and stirred at 80 °C under a nitrogen atmosphere. A mixture of 25.8 g of glycidyl methacrylate, 12.0 g of 2-phenoxyethyl acrylate, 12.9 g of tricyclodecanyl acrylate, 46.7 g of PGMEA, and a mixture of 4.45 g of dimethyl 2,2-azobis(2-methylpropionate) and 46.7 g of PGMEA were added thereto simultaneously and each over a period of 2 hours. After further heating and stirring for 16 hours, the mixture was cooled to 60 °C, 200 g of heptane was added, and then the mixture was cooled to room temperature and allowed to stand for 2 hours. The upper layer was separated off, 100 g of PGMEA was added, and then heptane was distilled off under reduced pressure to obtain a PGMEA solution of the target polymer (R-2).

[0552] The weight-average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the results were as follows.

[0553] (R-2): Mw = 7700, Mw / Mn = 1.90

[0554] (Synthesis Example 11)

[0555] Synthesis of Resin (R-3)

[0556] [Chemical Formula 58]

[0557]

[0558] 10.0 g of the compound (G-1) in the raw material group and 30 ml of 1-methoxy-2-propanol were weighed into a 200-ml three-necked flask, stirred in an oil bath at 75 °C under a nitrogen atmosphere to dissolve them. 0.25 g of paraformaldehyde was added, and a 1-methoxy-2-propanol solution of 2.5 g of 20 mass% p-toluenesulfonic acid monohydrate was added dropwise. After the addition was completed, the temperature of the oil bath was raised to 85 °C and the reaction was carried out for 4 hours. After cooling to room temperature, it was diluted with 100 ml of methyl isobutyl ketone, the insoluble components were separated by filtration, transferred to a separatory funnel, and washed 8 times by liquid separation with 30 ml of ultrapure water. The organic layer was concentrated under reduced pressure to recover the polymer, and dried under reduced pressure to obtain the polymer (R-3) for the fluidity promoter.

[0559] The weight-average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the results were as follows.

[0560] (R-3): Mw = 4920, Mw / Mn = 1.75

[0561] (Synthesis Example 12)

[0562] Synthesis of Resin (R-4)

[0563] [Chemical Formula 59]

[0564]

[0565] Under a nitrogen atmosphere, 42.8 g of compound (G-2) in the raw material group, 15.7 g of potassium carbonate, and 150 g of DMF were added to form a homogeneous dispersion at an internal temperature of 50°C. 28.2 g of modifier (c-1) was slowly added, and the reaction was carried out at an internal temperature of 50°C for 24 hours. 300 ml of methyl isobutyl ketone and 300 g of pure water were added to the reaction solution to dissolve the precipitated salt, and then the separated aqueous layer was removed. The organic layer was washed 6 times with 100 g of 3% nitric acid aqueous solution and 100 g of pure water, and then the organic layer was dried under reduced pressure to obtain the compound (R-4) for the fluidity promoter.

[0566] The weight-average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the results were as follows.

[0567] (R-4): Mw = 560, Mw / Mn = 1.01

[0568] (Synthesis Example 13)

[0569] Synthesis of Resin (R-5)

[0570] [Chemical Formula 60]

[0571]

[0572] 90 g of 2-phenylphenol, 15.6 g of 9-anthracenemethanol, and 9.8 g of divinylbenzene were dissolved in 25 g of cyclopentyl methyl ether and 90 g of diethylene glycol dimethyl ether. Under a nitrogen atmosphere, the mixture was stirred at room temperature for 5 minutes. Then, 1.14 g of trifluoromethanesulfonic acid was added, and the mixture was stirred for another 5 minutes. Subsequently, the mixture was stirred at 140°C for 3 hours. The reaction mixture was cooled, diluted with 250 ml of cyclopentyl methyl ether, transferred to a separatory funnel, washed with ultrapure water, and then the polymer was precipitated with hexane. The precipitated polymer was filtered, recovered, and dried under reduced pressure to obtain the target polymer (R-5).

[0573] The weight-average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the results were as follows.

[0574] (R-5): Mw = 1960, Mw / Mn = 1.45.

[0575] (Synthesis Example 14)

[0576] Synthesis of Resin (R-6)

[0577] [Chemical Formula 61]

[0578]

[0579] A mixture of 5.63 g of 9,9-bis(6-glycidyloxy-2-naphthyl)fluorene, 3.76 g of 6-hydroxy-2-naphthoic acid, 0.1 g of benzyltriethylammonium chloride, and 40 g of N-methylpyrrolidone was stirred at 120 °C for 20 hours. After cooling, 2.76 g of potassium carbonate and 2.62 g of propargyl bromide were added, and the mixture was stirred at 60 °C for 20 hours. It was diluted with ethyl acetate, washed three times with water, and concentrated under reduced pressure to synthesize an intermediate. To the obtained intermediate, 40 g of N-methylpyrrolidone and 1.99 g of acryloyl chloride were added, stirred, and 2.23 g of triethylamine was added dropwise thereto, and the mixture was stirred for 20 hours. It was diluted with ethyl acetate, washed three times with water, concentrated under reduced pressure, and purified by silica gel column chromatography to obtain 8.98 g of compound (R-6).

[0580] The weight-average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the results were as follows.

[0581] (R-6): Mw = 1613, Mw / Mn = 1.10.

[0582] The structure of the obtained resin for promoting fluidity, the weight-average molecular weight (Mw), and the dispersity (Mw / Mn) are shown in Tables 1 to 3.

[0583] [Table 1]

[0584]

[0585] [Table 2]

[0586]

[0587] [Table 3]

[0588]

[0589] [(A) Metal Oxide Nanoparticles]

[0590] The (A) metal oxide nanoparticles (A-1) used in the composition for forming a metal oxide film were ZrO 2 nanoparticles (5 nm core, 915505, Sigma-Aldrich Corp).

[0591] [(A) Comparative Metal Compound]

[0592] The comparative metal compound (A-2) used in the composition for forming a metal oxide film was synthesized according to the following procedure with reference to [Synthesis Example A-II] of Japanese Patent Publication No. 5756134.

[0593] To a mixture of 32.7 g of zirconium tetraisopropoxide, 50 g of isopropyl alcohol, and 50 g of acetylacetone, a mixture of 2.7 g of pure water and 50 g of isopropyl alcohol was added dropwise. After the addition was completed, the mixture was stirred for 2 hours for hydrolysis and condensation, and then refluxed for 2 hours. 200 g of PGMEA was added thereto, and the mixture was concentrated under reduced pressure to obtain 250 g of a PGMEA solution containing the zirconium-containing compound (A-2).

[0594] (A-2) is a hydrolysis condensate of a metal alkoxide and becomes a polymer having a main chain skeleton of polymetalloxane. Therefore, it can be clearly distinguished from metal oxide nanoparticles in terms of structure. Thus, it is used in the comparative example.

[0595] [(C) Dispersion stabilizer]

[0596] The compounds described in Tables 4 and 5.

[0597] C-1: The compound represented by the following formula (C-1)

[0598] C-2: The compound represented by the following formula (C-2)

[0599] C-3: The compound represented by the following formula (C-3)

[0600] C-4: The compound represented by the following formula (C-4)

[0601] C-5: The compound represented by the following formula (C-5)

[0602] RC-1: The compound represented by the following formula (RC-1)

[0603] RC-2: The compound represented by the following formula (RC-2)

[0604] RC-3: The compound represented by the following formula (RC-3) [Table 4]

[0605]

[0606] [Table 5]

[0607]

[0608] [(E) Crosslinking agent]

[0609] The (E) crosslinking agent used in the composition for forming a metal oxide film is as follows.

[0610] [Chemical Formula 62]

[0611]

[0612] [(F) Thermal acid generator]

[0613] The (F) thermal acid generator used in the composition for forming a metal oxide film is as follows.

[0614] [Chemical formula 63]

[0615]

[0616] [Composition UDL-1 for forming a metal oxide film]

[0617] The metal oxide nanoparticles (A-1) and the fluidity promoter (B-1) were dissolved in propylene glycol monomethyl ether acetate (PGMEA) containing 0.5 mass% of the surfactant FC-4430 (manufactured by Sumitomo 3M Co., Ltd.) in the proportions shown in Table 6, and filtered through a 0.02 μm membrane filter to prepare a composition for forming a metal oxide film (UDL-1).

[0618] [Compositions UDL-2 to 14 for forming a metal oxide film and Comparative Examples UDL-1 to 14]

[0619] The types and contents of the respective components were set as shown in Tables 6 and 7, and the respective liquid medicines were prepared by the same operations as UDL-1 except for this. Also, in Tables 6 and 7, "-" represents that the component was not used. The additive (G'-1) used was pentaerythritol triacrylate.

[0620] [Table 6]

[0621]

[0622] [Table 7]

[0623]

[0624] [Evaluation of crack resistance (Examples 1-1 to 1-14, Comparative Examples 1-1 to 1-18)]

[0625] The above compositions for forming a metal oxide film (UDL-1 to 14 and Comparative UDL-1 to 18) were coated on a silicon substrate, and a coating film was formed by baking at 350 °C for 60 seconds in the atmosphere, and the film thickness a was measured. PGMEA solvent was dropped thereon, left for 30 seconds and spun dry, and baked at 100 °C for 60 seconds to evaporate the PGMEA solvent, and the film thickness b was measured, and the film thickness difference before and after the PGMEA treatment was obtained to evaluate the solvent resistance. Also, it was evaluated whether there were cracks in each coating film before and after dropping the PGMEA solvent. When no cracks were observed, it was rated as "○" (good), and when cracks occurred, it was rated as "×" (bad).

[0626] The results are shown in Tables 8 and 9.

[0627] [Table 8]

[0628]

[0629] [Table 9]

[0630]

[0631] As shown in Tables 8 and 9, in Examples 1-1 to 1-14 using the composition for forming a metal oxide film (UDL-1 to 14) of the present invention, the film-forming property was good and there was almost no film loss due to solvent treatment, and it was found that a film with good solvent resistance was obtained. The content of the fluidity promoter in Example UDL-14 was 25%, and the content of the metal oxide film nanoparticles in Example UDL-12 was 38% at a high concentration. In each case, a metal oxide film with a film thickness of 2 μm could be formed without cracks. That is, when the content of the (B) fluidity promoter of the present invention is 9% or more, preferably the weight ratio of the (A) metal oxide nanoparticles to the aforementioned (B) fluidity promoter is 80 / 20 to 10 / 90, a metal oxide film can be formed with a thick film with excellent coatability. On the other hand, in Comparative UDL-3 to 4, Comparative UDL-11 to 14 using R-3 and R-4 having a cardo structure as the fluidity promoter, and Comparative UDL-5 using R-5 which is a high-carbon polymer, crack generation was observed.

[0632] In Comparative UDL-7 in which the metal oxide nanoparticles of UDL-1 were changed to Polymer A-2 which is a hydrolysis condensate of a metal alkoxide and has a main chain skeleton of a polymetaloxane, crack generation was also observed. A metal compound having a polymer structure such as A-2 has low heat resistance and large thermal shrinkage during baking, and it is presumed that cracks occurred. On the other hand, in Comparative UDL-8 using only metal oxide nanoparticles A-1, cracks were also observed. Thus, in order to form a metal oxide film with excellent coatability in a thick film, it is necessary to add a fluidity promoter, and it can be said that this fluidity promoter is a resin having a structural unit represented by the general formula (1) of the present invention, and it is necessary that it does not contain a compound / polymer having a cardo structure and a high-carbon polymer.

[0633] [Evaluation of storage stability (Examples 2-1 to 2-14, Comparative Examples 2-1 to 2-9)]

[0634] Regarding the metal oxide films of Examples UDL-1 to 14 and Comparative UDL-1 to 2, Comparative UDL-6, Comparative UDL-9 to 10, Comparative UDL-15 to 18 with good coatability in the above-mentioned crack resistance evaluation, the number of defects with a size of 100 nm was confirmed using an SP2 (defect inspection device) manufactured by KLA-TENCOR Corporation. Also, the particles in the liquid of the composition for forming the metal oxide film were measured using a KS-41 (liquid particle counter) manufactured by KRION Co., Ltd. The counting of particles with a size of 0.15 μm or more contained in 1 mL was performed 5 times, and the average value was used as the measured value. Furthermore, after storing for 6 months in an environment at 10°C, the same method as above was carried out to confirm the number of defects and the number of particles in the liquid.

[0635] The results are shown in Table 10.

[0636] [Table 10]

[0637]

[0638] As shown in Table 10, in Examples 2-1 to 2-14 using the composition for forming a metal oxide film (UDL-1 to 14) of the present invention, the number of particles in the liquid and the number of defects after coating were small after storing for 6 months, indicating excellent storage stability. On the other hand, in Comparative Example 2-6 using Comparative UDL-15 in which the (C) dispersion stabilizer was removed from UDL-13, and in Comparative Examples 2-7 to 2-9 using RC-1 to 3 as the (C) dispersion stabilizer, an increase in the number of particles and the number of defects after coating was observed after 6 months. It is speculated that this is due to poor dispersion stability of the metal oxide nanoparticles in the composition, resulting in aggregation of the nanoparticles during long-term storage.

[0639] [Etching Resistance Evaluation (Examples 3-1 to 3-11, Comparative Examples 3-1 to 3-5)]

[0640] The compositions for forming metal oxide films of Examples UDL-1 to 11 and Comparative UDL-1 to 2, Comparative UDL-6, Comparative UDL-9 to 10 with good coatability in the above-mentioned crack resistance evaluation were coated on a silicon substrate, baked in the atmosphere at 350°C for 60 seconds to form a coating film with a thickness of 1000 nm, and the film thickness a was measured. Then, etching was performed for 1 minute using a CF 4 gas and O 2 gas using an etching device Telius manufactured by Tokyo Electron Limited, and the film thickness b was measured.

[0641] Calculate the film thickness etched by the CF 4 gas within 1 minute (film thickness b - film thickness a), and define it as relative to CF 4The etching resistance of the gas is rated as "A" (extremely good) when the film thickness difference between b and a is less than 60 nm, "B" (good) when it is 60 nm or more and less than 70 nm, and "C" (poor) when it is 70 nm or more.

[0642] Calculate the film thickness etched by O 2 gas within 1 minute (film thickness d - film thickness c), which is defined as relative to O 2 The etching resistance of the gas is rated as "A" (extremely good) when the film thickness difference between c and d is less than 75 nm, "B" (good) when it is 75 nm or more and less than 85 nm, and "C" (poor) when it is 85 nm or more.

[0643] The results are shown in Table 11.

[0644] For dry etching with CF 4 gas conditions

[0645] Chamber pressure: 100 mT

[0646] RF power (upper): 500 W

[0647] RF power (lower): 400 W

[0648] CF 4 Gas flow rate: 300 sccm

[0649] Time: 60 sec

[0650] For dry etching with O 2 gas conditions

[0651] Chamber pressure: 15 mT

[0652] RF power (upper): 300 W

[0653] RF power (lower): 50 W

[0654] O 2 Gas flow rate: 30 sccm

[0655] N 2 Gas flow rate: 270 sccm

[0656] Time: 60 sec

[0657] [Table 11]

[0658]

[0659] As shown in Table 11, when comparing the compositions where (A) the content of metal oxide nanoparticles is 6% and (B) the content of the fluidity promoter is 15%, in Examples 3-1 to 3-10 using the composition for forming a metal oxide film of the present invention, it was confirmed that, compared with Comparative Examples 3-2 to 3-3, the etching resistance to CF 4 gas and O 2 gas is more excellent. Excellent etching resistance is shown for both CF 4 gas and O 2 gas, thus suggesting its usefulness as a mask when etching an Si-based substrate to be processed with CF 4 -based gas, and in the reversal process of removing an organic resist underlayer film pattern with O 2 -based gas and reversing the above pattern into a metal oxide film, etc.

[0660] For example, the composition of Comparative Example 3-4 which contains only a fluidity promoter without metal oxide nanoparticles cannot form a film with excellent dry etching resistance. On the other hand, even for compositions containing metal oxide nanoparticles, depending on the selected fluidity promoter, the dry etching resistance varies. In Comparative Example 3-2, since an acrylic resin is used as the fluidity promoter, the dry etching resistance deteriorates. On the other hand, in Comparative Example 3-3, the fluidity promoter R-6 used is a compound with a cardo structure having excellent dry etching resistance, but since the crosslinking group has a highly flexible acrylate, it is presumed that a dense cured film cannot be formed and the dry etching resistance deteriorates. In Comparative Example 3-5, a composition using trimethylolpropane triacrylate which is generally used as a UV curing binder instead of a fluidity promoter, like Comparative Example 3-2 and Comparative Example 3-3, is not suitable for forming a film with excellent dry etching resistance.

[0661] That is to say, in order to achieve a composition with excellent dry etching resistance and cracking resistance capable of forming a thick film, it can be said that it is important to use a resin having a structural unit represented by the above general formula (1) as the fluidity promoter.

[0662] [Evaluation of filling characteristics (21 Examples 4-1 to 4-14, 18 Comparative Examples 4-1 to 4-18)]

[0663] The above composition for forming a metal oxide film (UDL-1 to 14 and Comparative Example UDL-1 to 18) was coated on a SiO 2 wafer substrate having a dense hole pattern (hole diameter 0.16 μm, hole depth 2.0 μm, distance between the centers of two adjacent holes 0.40 μm), and heated at 350 °C for 60 seconds using a hot plate to form a metal oxide film. Similarly, it was heated at 350 °C for 60 seconds in the atmosphere, and then baked at 450 °C for 60 seconds under a nitrogen gas flow with an oxygen concentration controlled to be 0.2% or less to form a metal oxide film. The substrate used had a structure as Figure 4The base substrate 17 (SiO 2 wafer substrate) shown in (AA) (bird's-eye view) and (AB) (cross-sectional view) and having a dense hole pattern. The cross-sectional shape of each wafer substrate was observed using an electron microscope (S-4700) manufactured by Hitachi, Ltd., and it was confirmed whether there were pores (voids) inside the metal oxide film filled in the holes. The results are shown in Tables 12 and 13. When a metal oxide film-forming composition with poor filling characteristics was used, pores appeared inside the metal oxide film filled in the holes in this evaluation. When a metal oxide film-forming composition with good filling characteristics was used, as shown in Figure 4 (AC), the metal oxide film 18 can be filled in the holes without pores and peeling.

[0664] [Table 12]

[0665]

[0666] [Table 13]

[0667]

[0668] As shown in Tables 12 and 13, in Examples 4-1 to 4-14 using the metal oxide film-forming composition (UDL-1 to 14) of the present invention, high-aspect-ratio dense hole patterns can be filled without pores, and good filling characteristics are confirmed. On the other hand, in Comparative Example 4-8 of Comparative UDL-8 using only metal oxide nanoparticles, the fluidity was insufficient, so significant pores were observed.

[0669] In Comparative Example 4-15 without using a dispersion stabilizer, several minute pores were observed. Also, in Comparative Examples 4-16 to 4-18 using a dispersion stabilizer with a weight reduction rate of more than 30% from 30 °C to 190 °C, perhaps the effect on promoting the thermal fluidity effect of the fluidity promoter was weak, and minute pores were also observed. That is, in order to achieve a metal oxide film-forming composition with excellent filling properties for high-aspect-ratio patterns, it is preferably to add not only a fluidity promoter but also a dispersion stabilizer having an effect of further enhancing the thermal fluidity of the resin for the thermal fluidity promoter. The dispersion stabilizer used in the present invention not only improves the dispersion stability of the metal oxide nanoparticles in the composition but also has the effect of enhancing the thermal fluidity of the composition.

[0670] As in Examples 4-7 to 4-8, by using B-7 and B-8 in the fluidity promoter, the modification rate of the hydroxyl group can be appropriately controlled, and good filling properties and substrate adhesion can be achieved to a high degree. In Example 4-10, by combining and adjusting the resin R-1 with a propargyloxy group and the resin B-1 with a hydroxyl group, the same effect as in Example 4-7 can be obtained. On the other hand, in Comparative Examples 4-1, 4-4, and 4-6, no pores were observed inside the holes, but the amount of hydroxyl groups in the fluidity promoter was insufficient, so deterioration of adhesion to the substrate was observed. It can be said that in order to exhibit adhesion to the substrate, it is better to contain a certain amount of hydroxyl groups.

[0671] Comparative UDL-7, in which the metal oxide nanoparticles of UDL-1 were changed to polymer A-2 which is a hydrolysis condensate of metal alkoxide and has a main chain skeleton of polymetalloxane, has low heat resistance and large thermal shrinkage during baking, so it is speculated that it will not fill up to the bottom of the substrate and significant pores will be observed. In Comparative Example 4-2, the heat resistance of R-2 used as the fluidity promoter was insufficient, and it is considered that pores occurred during baking at 350 °C. In Comparative Example 4-10, since the heat resistance of neopentyl glycol triacrylate used instead of the fluidity promoter was insufficient, pores were presumably observed. On the other hand, in Comparative Examples 4-3 and 4-5, R-3 and R-5 with excellent heat resistance were used as the fluidity promoter, but they lacked fluidity, and it was speculated that pores occurred in the filling of high aspect ratio patterns. In Comparative Example 4-13, the film was thickened by increasing the content of the fluidity promoter from 15% to 20% compared with Comparative Example 4-3, but no improvement in pores was seen. Also, in Comparative Example 4-14, where the weight ratio of the fluidity promoter to the metal oxide nanoparticles was set to 90 / 10 to increase the ratio of the fluidity promoter, pore formation was also observed. In Comparative Examples 4-11 and 4-12 using Comparative UDL-11 and 12 with R-3, pores were also observed.

[0672] That is, in order to form a metal oxide with excellent filling properties that can well fill high aspect ratio patterns, the presence of a fluidity promoter is indispensable. However, high-carbon polymers such as polymers R-3 and R-5 with a rigid cardo structure have poor fluidity, so they are not suitable. It can be said that it is important to use a resin having a structural unit represented by the general formula (1) of the present invention.

[0673] [Pattern formation method (Examples 5-1 to 5-11, Comparative Examples 5-1 to 5-5)]

[0674] The metal oxide film-forming compositions of Examples UDL-1 to 11 and Comparative UDL-1 to 2, Comparative UDL-6, Comparative UDL-9 to 10 with good coatability in the above crack resistance evaluation were respectively coated on 1000 nm SiO which had been formed with a trench pattern (trench width 10 μm, trench depth 0.50 μm).2 On the silicon wafer substrate of the film, in the atmosphere, calcination is carried out at 350 °C for 60 seconds to form a metal-containing film with a film thickness of 1000 nm. A resist intermediate layer material (SOG-1) containing silicon atoms is coated thereon, baked at 220 °C for 60 seconds to form a resist intermediate layer film with a film thickness of 40 nm. A single-layer resist for ArF is coated on the resist intermediate layer film as the resist upper layer film material, baked at 105 °C for 60 seconds to form a photoresist film with a film thickness of 100 nm.

[0675] The resist intermediate layer material (SOG-1) containing silicon atoms is prepared by dissolving an ArF silicon-containing intermediate film polymer (SiP1) and a crosslinking catalyst (CAT1) in an organic solvent containing 0.1% by mass of FC-4430 (manufactured by Sumitomo 3M Limited) in the ratio shown in Table 14, and filtering with a fluororesin filter having a pore size of 0.1 μm to prepare the resist intermediate layer material (SOG-1) containing silicon atoms.

[0676] [Table 14]

[0677]

[0678] The structural formulas of the ArF silicon-containing intermediate film polymer (SiP1) and the crosslinking catalyst (CAT1) used are shown below.

[0679] [Chemical formula 64]

[0680]

[0681] The resist upper layer film material (single-layer resist for ArF) is prepared by dissolving a polymer (RP1), an acid generator (PAG1), and a basic compound (Amine1) in a solvent containing 0.1% by mass of a surfactant FC-4430 (manufactured by Sumitomo 3M Co., Ltd.) in the ratio of Table 15, and filtering with a 0.1 μm fluororesin filter.

[0682] [Table 15]

[0683]

[0684] The polymer (RP1), the acid generator (PAG1), and the basic compound (Amine1) used in the resist upper layer film material (single-layer resist for ArF) are as follows.

[0685] [Chemical formula 65]

[0686]

[0687] Next, exposure was performed using an ArF immersion exposure apparatus (manufactured by Nikon Corporation; NSR-S610C, NA 1.30, σ 0.92 / 0.74, 35-degree crosspole, 6% halftone phase shift mask), followed by baking at 100 °C for 60 seconds (PEB), and development for 30 seconds with a 2.38 mass% aqueous solution of tetramethylammonium hydroxide (TMAH) to obtain a 100 nm 1:1 positive line-and-space pattern (resist pattern).

[0688] Then, dry etching using an etching apparatus CE-300I manufactured by ULVAC was performed, with the resist pattern as a mask to etch the organic antireflective film and the silicon atom-containing resist intermediate layer material (SOG-1) to form a hard mask pattern. The obtained SOG-1 pattern was used as a mask to etch the metal oxide film to form a metal oxide film pattern, and the obtained metal oxide film pattern was used as a mask to etch the SiO 2 film. The etching conditions are as follows.

[0689] Transfer conditions of the resist pattern to the silicon atom-containing resist intermediate layer material (SOG-1).

[0690] For dry etching conditions in CF 4 gas

[0691] Pressure: 1 Pa

[0692] Antenna RF power: 100 W

[0693] Bias RF power: 15 W

[0694] CF 4 Gas flow rate: 15 sccm

[0695] Time: 60 sec

[0696] Transfer conditions of the silicon atom-containing resist intermediate layer material (SOG-1) pattern to the metal oxide film.

[0697] For dry etching conditions in Cl 2 gas

[0698] Pressure: 1 Pa

[0699] Antenna RF power: 320 W

[0700] Bias RF power: 30 W

[0701] Cl 2 Gas flow rate: 25 sccm

[0702] Time: 1200 sec

[0703] Metal oxide film pattern for SiO2 Transfer conditions of the film

[0704] For CF 4 Dry etching conditions of the gas

[0705] Pressure: 1 Pa

[0706] Antenna RF power: 100 W

[0707] Bias RF power: 15 W

[0708] CF 4 Gas flow rate: 15 sccm

[0709] Time: 450 sec

[0710] The pattern cross-section was observed with an electron microscope (S-4700) manufactured by Hitachi, Ltd., and the results are shown in Table 16.

[0711] [Table 16]

[0712]

[0713] As shown in Table 16, in Examples 5-1 to 5-11 using the composition for forming a metal oxide film (UDL-1 to 11) of the present invention, the resist upper layer film patterns were all finally transferred well to the substrate, and a line and space pattern with a depth of 1 μm was formed. That is, it was confirmed that the composition for forming a metal oxide film of the present invention is suitable for microfabrication using the multilayer resist method.

[0714] On the other hand, in Comparative Example 5-1 using Comparative UDL-1 in which the adhesion to the substrate was confirmed to be insufficient in the landfill property evaluation, pattern collapse occurred during pattern processing, and finally a good pattern could not be obtained. Also, in Comparative Examples 5-2 to 5-5 using Comparative UDL-2, 6, 9, and 10 in which the performance was confirmed to be insufficient in the dry etching resistance evaluation, the pattern shape was distorted during pattern processing, and finally a good pattern could not be obtained.

[0715] [SOC pattern inversion method (Examples 6-1 to 6-11, Comparative Examples 6-1 to 6-6)]

[0716] On the SiO where 2000 nm has been formed 2A coating-type organic underlayer film material (SOC-1) as an underlayer film for a resist is coated on a silicon wafer substrate of the film, baked at 350 °C for 60 seconds to form an underlayer film for a resist with a film thickness of 1500 nm. An ArF resist intermediate layer material containing silicon atoms (SOG-1) is coated thereon, baked at 220 °C for 60 seconds to form an intermediate layer film for a resist with a film thickness of 45 nm. A single-layer resist for ArF is coated as an upper layer resist film material thereon, baked at 105 °C for 60 seconds to form a photoresist film with a film thickness of 100 nm. An immersion protective film material (TC-1) is coated on the photoresist film, baked at 90 °C for 60 seconds to form a protective film with a film thickness of 50 nm.

[0717] As the upper layer resist film material (single-layer resist for ArF), the same material as that used in the above-described pattern formation method (Example 5) is used.

[0718] The coating-type organic underlayer film material (SOC-1) is prepared by dissolving a polymer for an underlayer film for a resist (SOP1) in an organic solvent containing 0.5 mass% of FC-4430 (manufactured by Sumitomo 3M Limited) at the ratio shown in Table 17, and filtering through a fluororesin filter with a pore diameter of 0.2 μm to prepare the coating-type organic underlayer film material (SOC-1).

[0719] [Table 17]

[0720]

[0721] The structural formula of the polymer for an underlayer film for a resist (SOP1) used is shown in Table 18.

[0722] [Table 18]

[0723]

[0724] The ArF silicon-containing intermediate film polymer (SiP1) and the crosslinking catalyst (CAT1) are dissolved in an organic solvent containing 0.1 mass% of FC-4430 (manufactured by Sumitomo 3M Limited) at the ratio shown in Table 19, and filtered through a fluororesin filter with a pore diameter of 0.1 μm to prepare the ArF silicon-containing intermediate film polymer (SiP1) and the crosslinking catalyst (CAT1).

[0725] [Table 19]

[0726]

[0727] The structural formulas of the ArF silicon-containing intermediate film polymer (SiP1) and the crosslinking catalyst (CAT1) used are shown below.

[0728] [Chemical formula 66]

[0729]

[0730] Next, exposure was performed using an ArF immersion exposure apparatus (manufactured by Nikon Corporation; NSR-S610C, NA 1.30, σ 0.92 / 0.74, 35-degree crosspole, 6% half-tone phase shift mask), followed by baking at 100 °C for 60 seconds (PEB), and development for 30 seconds with a 2.38 mass% aqueous solution of tetramethylammonium hydroxide (TMAH) to obtain a 100 nm 1:1 positive line-and-space pattern (resist pattern).

[0731] Next, using the etching apparatus Telius manufactured by Tokyo Electron Limited, the resist pattern was used as a mask to etch and process a resist intermediate layer material containing silicon atoms (SOG-1) by dry etching to form a hard mask pattern, and the obtained hard mask pattern was used as a mask to etch the underlying resist film (SOC-1) to form an SOC-1 film pattern. The etching conditions are shown below.

[0732] Transfer conditions of the resist pattern to the resist intermediate layer material containing silicon atoms (SOG-1).

[0733] Chamber pressure: 50 mT

[0734] RF power (upper): 500 W

[0735] RF power (lower): 300 W

[0736] CF 4 Gas flow rate: 150 sccm

[0737] CHF 3 Gas flow rate: 50 sccm

[0738] Time: 20 sec

[0739] Transfer conditions of the resist intermediate layer material containing silicon atoms (SOG-1) pattern to the underlying resist film (SOC-1).

[0740] Chamber pressure: 10 mT

[0741] RF power (upper): 1,000 W

[0742] RF power (lower): 300 W

[0743] CO 2 Gas flow rate: 150 sccm

[0744] CO gas flow rate: 50 sccm

[0745] N 2 Gas flow rate: 50 sccm

[0746] H 2 Gas flow rate: 150 sccm

[0747] Time: 600 sec

[0748] Next, the composition for forming the metal oxide film (UDL-1 to 11, Comparative UDL-1, 2, 6, 9, 10) is coated on the obtained SOC-1 film pattern, and calcined at 350 °C for 60 seconds in the atmosphere to form a metal oxide film with a film thickness of 1000 nm. After that, the metal oxide film covering the SOC-1 film pattern is etched to expose the top surface of the SOC-1 film pattern. The remaining SOG-1 film on the surface of the SOC-1 film pattern with the top surface exposed is etched away, and then the exposed SOC-1 is etched away. The pattern is inverted on the metal oxide film, and the obtained metal oxide film pattern is used as a mask for SiO 2 film etching. For the comparative example, without using the composition for forming the metal oxide film, using the SOC-1 film pattern as a mask, SiO 2 film etching is also performed (Comparative Example 6-6). The etching conditions are as follows.

[0749] Etching back of the metal oxide film (exposure of the SOC-1 film pattern).

[0750] Pressure: 1 Pa

[0751] Antenna RF power: 320 W

[0752] Bias RF power: 30 W

[0753] Cl 2 Gas flow rate: 25 sccm

[0754] Time: 300 sec

[0755] Removing the resist intermediate layer material (SOG-1) film containing silicon atoms from the SOC-1 film pattern.

[0756] Pressure: 1 Pa

[0757] Antenna RF power: 100 W

[0758] Bias RF power: 15 W

[0759] CF 4 Gas flow rate: 15 sccm

[0760] Time: 60 sec Removal of the SOC-1 film pattern.

[0761] Pressure: 1 Pa

[0762] Antenna RF power: 300 W

[0763] Bias RF power: 0 W

[0764] O 2 Gas flow rate: 25 sccm

[0765] Time: 500 sec

[0766] Metal oxide film pattern for SiO 2 Transfer conditions for the film.

[0767] Pressure: 1 Pa

[0768] Antenna RF power: 100 W

[0769] Bias RF power: 15 W

[0770] CF 4 Gas flow rate: 15 sccm

[0771] Time: 900 sec

[0772] Comparative Example 6-6: Transfer conditions for the SOC-1 film pattern for SiO 2 film.

[0773] Pressure: 1 Pa

[0774] Antenna RF power: 100 W

[0775] Bias RF power: 15 W

[0776] CF 4 Gas flow rate: 15 sccm

[0777] Time: 900 sec

[0778] The pattern cross-section was observed with a scanning electron microscope (S-4700) manufactured by Hitachi, Ltd., and the results are shown in Table 20.

[0779] [Table 20]

[0780]

[0781] As shown in Table 20, in Examples 6-1 to 6-11 using the composition for forming a metal oxide film (UDL-1 to 11) of the present invention, the SOC-1 film patterns were all inverted with good accuracy, without pattern collapse, and the inverted patterns were finally well transferred to the substrate. Thus, it was confirmed that the composition for forming a metal oxide film of the present invention is suitable for microfabrication using a tone inversion etching method in a multilayer resist process. On the other hand, the SOC-1 film pattern was directly transferred to SiO 2In Comparative Example 6-6 of the film, the etching resistance of the SOC-1 film was not satisfactory, so the distortion of the pattern shape was confirmed. Also, in Comparative Example 6-1 where insufficient adhesion to the substrate was confirmed in the filling property evaluation, pattern collapse occurred during pattern processing, and finally a good inverted pattern could not be obtained. On the other hand, in Comparative Examples 6-2 to 6-5 where insufficient performance was confirmed in the dry etching resistance evaluation, the etching selectivity for the SOC-1 film was not satisfactory, and it was speculated that the formation of the pattern could not be confirmed.

[0782] As can be understood from the above, if it is the composition for forming a metal oxide film of the present invention, not only is the storage stability excellent, a thick film with excellent crack resistance can be formed, and a high level of filling property and dry etching resistance are taken into account. Therefore, it is extremely useful as a resist underlayer film material used in the multilayer resist method and a reversal agent used in the tone inversion etching method. Also, if it is the pattern forming method of the present invention using this composition, even if the object to be processed is a substrate with height differences, fine patterns can be formed with high precision.

[0783] This specification includes the following aspects.

[0784] [1]: A composition for forming a metal oxide film, characterized by comprising:

[0785] (A) Metal oxide nanoparticles;

[0786] (B) A fluidity promoter of a resin containing a structural unit represented by the following general formula (1),

[0787] (C) A dispersion stabilizer composed of an aromatic-containing compound having two or more benzene rings, or one benzene ring and a structure represented by the following general formula (C-1) and having a molecular weight of 500 or less in terms of molecular formula, and

[0788] (D) An organic solvent,

[0789] The content of the (B) fluidity promoter relative to the whole composition is 9% by mass or more, the ratio Mw / Mn of the weight-average molecular weight Mw to the number-average molecular weight Mn measured by gel permeation chromatography is 2.50 ≤ Mw / Mn ≤ 9.00, and it does not contain a compound or polymer having a cardo structure.

[0790] [Chemical formula 67]

[0791]

[0792] In the general formula (1), R a is a saturated monovalent organic group having 1 to 30 carbon atoms or an unsaturated monovalent organic group having 2 to 30 carbon atoms, X is a divalent organic group having 1 to 30 carbon atoms, p is an integer of 0 to 5, q 1 is an integer of 1 to 6, p + q1 is an integer from 1 to 6, q 2 is 0 or 1,

[0793] [Chemical Formula 68]

[0794]

[0795] In the formula, * represents the bonding position, and W is an organic group having 1 to 4 carbon atoms.

[0796] [2]: A composition for forming a metal oxide film as in [1], wherein the (B) fluidity promoter is a fluidity promoter containing a resin having a structural unit represented by the general formula (1) and further containing a resin having a structural unit represented by the following general formula (2), or is a resin having both the structural unit represented by the general formula (1) and the structural unit represented by the following general formula (2).

[0797] [Chemical Formula 69]

[0798]

[0799] In the general formula (2), R a is a saturated monovalent organic group having 1 to 30 carbon atoms or an unsaturated monovalent organic group having 2 to 30 carbon atoms, R b is a saturated hydrocarbon group having 1 to 30 carbon atoms or an unsaturated hydrocarbon group having 2 to 10 carbon atoms, X is a divalent organic group having 1 to 30 carbon atoms, p is an integer from 0 to 5, q 1 is an integer from 1 to 6, p + q 1 is an integer from 1 to 6, q 2 is 0 or 1.

[0800] [3]: A composition for forming a metal oxide film as in [2], wherein in the general formula (2), R b is an alkyl group having 1 to 30 carbon atoms or any one of the structures represented by the following general formula (3). When the proportion of the general formula (1) is a and the proportion of the general formula (2) is b, the content of the general formula (2) satisfies the relationship of a + b = 1 and 0.2 ≤ b ≤ 0.8.

[0801] [Chemical Formula 70]

[0802]

[0803] In the general formula (3), * represents the bonding site to the oxygen atom, R A is a divalent organic group having 1 to 10 carbon atoms which may be substituted, R B is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms which may be substituted.

[0804] [4]: A composition for forming a metal oxide film according to any one of [1] to [3], wherein the weight reduction rate of the (C) dispersion stabilizer at 30°C to 190°C is less than 30%, and the weight reduction rate between 30°C and 350°C is 98% or more.

[0805] [5]: A composition for forming a metal oxide film according to any one of [1] to [4], wherein the (C) dispersion stabilizer contains one or more compounds selected from the following general formulas (I) to (III),

[0806] [Chemical formula 71]

[0807]

[0808] In the formula, R 1 are each independently a hydrogen atom, a hydroxyl group, or an optionally substituted organic group having 1 to 10 carbon atoms, and W 1 is a phenylene group or a divalent group represented by the following general formula (I-1), and W 2 , W 3 is a single bond or any divalent group represented by the following general formula (I-2), m 1 is an integer from 1 to 10, and n 1 is an integer from 0 to 5.

[0809] [Chemical formula 72]

[0810]

[0811] In the formula, * represents the bonding position, and R 10 , R 11 , R 12 , R 13 are a hydrogen atom, a hydroxyl group, or an organic group having 1 to 10 carbon atoms, and W 10 , W 11 each independently represents a single bond or a carbonyl group, and m 10 , m 11 are integers from 0 to 10, and m 10 +m 11 ≥1.

[0812] [Chemical formula 73]

[0813]

[0814] In the formula, * represents the bonding position.

[0815] [Chemical formula 74]

[0816]

[0817] In the formula, R 2Each independently represents a hydrogen atom, or an optionally substituted organic group having 1 to 10 carbon atoms, W 4 represents any divalent group represented by the following general formula (II-1), W 5 is a single bond or a divalent group represented by the following general formula (II-2), m 2 is an integer from 2 to 10, n 3 is an integer from 0 to 5,

[0818] [Chemical formula 75]

[0819]

[0820] In the formula, * represents the bonding position, R 20 、R 21 、R 22 、R 23 are a hydrogen atom, a hydroxyl group, or an organic group having 1 to 10 carbon atoms, m 20 、m 21 are integers from 0 to 10, m 20 +m 21 ≥1,

[0821] [Chemical formula 76]

[0822]

[0823] In the formula, * represents the bonding position,

[0824] [Chemical formula 77]

[0825]

[0826] In the formula, R 3 、R 4 are a hydrogen atom, a hydroxyl group, or an optionally substituted organic group having 1 to 10 carbon atoms, and may also bond to form a cyclic structure, R 5 、R 6 are organic groups having 1 to 10 carbon atoms, R 5 is a group containing any one of an aromatic ring or a divalent group represented by the following general formula (III-1), W 6 、W 7 is a single bond or any divalent group represented by the following general formula (III-2), and at least one is a divalent group represented by the following general formula (III-2),

[0827] [Chemical formula 78]

[0828]

[0829] In the formula, * represents the bonding position, W 30 is an organic group having 1 to 4 carbon atoms,

[0830] [Chemical 79]

[0831]

[0832] In the formula, * represents the bonding position.

[0833] [6]: A composition for forming a metal oxide film according to any one of [1] to [5], wherein the (A) metal oxide nanoparticles are one or more of metal oxide nanoparticles selected from the group consisting of zirconium, hafnium, aluminum, tungsten, titanium, copper, tin, cerium, indium, zinc, yttrium, lanthanum, chromium, cobalt, platinum, iron, antimony, and germanium.

[0834] [7]: A composition for forming a metal oxide film according to [6], wherein the (A) metal oxide nanoparticles are one or more selected from the group consisting of zirconium oxide nanoparticles, hafnium oxide nanoparticles, tungsten oxide nanoparticles, titanium oxide nanoparticles, and tin oxide nanoparticles.

[0835] [8]: A composition for forming a metal oxide film according to any one of [1] to [7], wherein the (A) metal oxide nanoparticles have an average primary particle size of 100 nm or less.

[0836] [9]: A composition for forming a metal oxide film according to any one of [1] to [8], wherein the weight ratio of the (A) metal oxide nanoparticles to the (B) fluidity promoter is 80 / 20 to 10 / 90.

[0837]

[10] : A composition for forming a metal oxide film according to any one of [1] to [9], wherein the composition for forming a metal oxide film further contains one or more of a crosslinking agent, a surfactant, and an acid generator.

[0838]

[11] : A pattern forming method, which is a method for forming a pattern on a substrate to be processed, characterized by including the following steps:

[0839] (I-1) After coating a composition for forming a metal oxide film according to any one of [1] to

[10] on the substrate to be processed, heat treatment is performed to form a metal oxide film.

[0840] (I-2) An upper resist film is formed on the metal oxide film using a photoresist material.

[0841] (I-3) After pattern exposure of the upper resist film, development is performed with a developer to form a pattern on the upper resist film.

[0842] (I-4) Using the patterned upper resist film as a mask, dry etching is performed to transfer the pattern to the metal oxide film, and

[0843] (I-5) Using the formed-pattern metal oxide film as a mask, processing the substrate to be processed to form a pattern on the substrate to be processed.

[0844]

[12] : A pattern formation method, which is a method for forming a pattern on a substrate to be processed, characterized by including the following steps:

[0845] (II-1) After coating a composition for forming a metal oxide film according to any one of [1] to

[10] on the substrate to be processed, performing heat treatment to form a metal oxide film.

[0846] (II-2) Forming a silicon-containing resist intermediate film on the metal oxide film using a silicon-containing resist intermediate film material.

[0847] (II-3) Forming a resist upper layer film on the silicon-containing resist intermediate film using a photoresist material.

[0848] (II-4) After subjecting the resist upper layer film to pattern exposure, developing it with a developer to form a pattern on the resist upper layer film.

[0849] (II-5) Using the formed-pattern resist upper layer film as a mask, transferring the pattern to the silicon-containing resist intermediate film by dry etching.

[0850] (II-6) Using the silicon-containing resist intermediate film with the transferred pattern as a mask, transferring the pattern to the metal oxide film step by dry etching, and

[0851] (II-7) Using the formed-pattern metal oxide film as a mask, processing the substrate to be processed to form a pattern on the substrate to be processed.

[0852]

[13] : A pattern formation method, which is a method for forming a pattern on a substrate to be processed, characterized by including the following steps:

[0853] (III-1) After coating a composition for forming a metal oxide film according to any one of [1] to

[10] on the substrate to be processed, performing heat treatment to form a metal oxide film.

[0854] (III-2) Forming an inorganic hard mask intermediate film selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film on the metal oxide film.

[0855] (III-3) Forming an organic thin film on the inorganic hard mask intermediate film.

[0856] (III-4) Forming a resist upper layer film on the organic thin film using a photoresist material.

[0857] (III-5) After pattern exposure of the upper resist film, develop it with a developer to form a pattern in the upper resist film.

[0858] (III-6) Use the patterned upper resist film as a mask and transfer the pattern to the intermediate organic film and inorganic hard mask film by dry etching.

[0859] (III-7) Use the inorganic hard mask intermediate film with the transferred pattern as a mask and transfer the pattern to the metal oxide film step by dry etching, and

[0860] (III-8) Use the patterned metal oxide film as a mask to process the substrate to be processed and form a pattern on the substrate to be processed.

[0861]

[14] : A pattern forming method, which is a method for forming a pattern on a substrate to be processed, characterized by including the following steps:

[0862] (IV-1) Form a lower resist film on the substrate to be processed.

[0863] (IV-2) Form a resist intermediate film or a combination of an inorganic hard mask intermediate film selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film and an organic film on the lower resist film.

[0864] (IV-3) Use a photoresist material to form an upper resist film on the resist intermediate film or the combination of the inorganic hard mask intermediate film and the organic film.

[0865] (IV-4) After pattern exposure of the upper resist film, develop it with a developer to form a pattern in the upper resist film.

[0866] (IV-5) Use the patterned upper resist film as a mask and transfer the pattern to the resist intermediate film or the organic film and the inorganic hard mask intermediate film by dry etching.

[0867] (IV-6) Use the patterned resist intermediate film or the inorganic hard mask intermediate film as a mask and transfer the pattern to the lower resist film by dry etching.

[0868] (IV-7) After coating the composition for forming a metal oxide film according to any one of [1] to

[10] on the patterned lower resist film, perform heat treatment to coat the metal oxide film and fill the spaces between the patterns of the lower resist film with the metal oxide film.

[0869] (IV-8) Etch back the metal oxide film coated on the patterned lower resist film by chemical stripping or dry etching to expose the top surface of the patterned lower resist film.

[0870] (IV-9) The resist intermediate film or inorganic hard mask intermediate film remaining on the top surface of the resist underlayer film is removed by dry etching.

[0871] (IV-10) The formed-patterned resist underlayer film with its surface exposed is removed by dry etching, and an inverted pattern of the original pattern is formed on the metal oxide film.

[0872] (IV-11) Using the metal oxide film with the inverted pattern formed thereon as a mask, the substrate to be processed is processed to form a tone-inverted pattern on the substrate to be processed.

[0873]

[15] : A pattern forming method, which is a pattern forming method using a metal oxide film forming composition on a sacrificial film, characterized by including the following steps:

[0874] (V-1) After coating the metal oxide film forming composition according to any one of [1] to

[10] on a substrate to be processed having a structure or height difference, heat treatment is performed to fill the metal oxide film.

[0875] (V-2) The metal oxide film outside the structure or height difference on the substrate to be processed is removed by CMP method, and the metal oxide film is removed from the surface of the substrate to be processed.

[0876] (V-3) An insulating film and a conductive film are alternately laminated on the substrate to be processed on which the metal oxide film has been filled.

[0877] (V-4) An organic resist underlayer film is formed on the laminated film of the insulating film and the conductive film formed on the substrate to be processed on which the metal oxide film has been filled.

[0878] (V-5) A 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, or a combination of the inorganic hard mask intermediate film and an organic thin film is formed on the organic resist underlayer film.

[0879] (V-6) On the resist intermediate film, or the inorganic hard mask intermediate film, or the combination of the inorganic hard mask and the organic thin film, a resist upper layer film is formed using a photoresist material.

[0880] (V-7) After the resist upper layer film is pattern-exposed, it is developed with a developer to form a pattern on the resist upper layer film.

[0881] (V-8) Using the formed-patterned resist upper layer film as a mask, the pattern is transferred to the resist intermediate film, or the inorganic hard mask intermediate film, or the organic thin film and the inorganic hard mask intermediate film by dry etching.

[0882] (V-9) Using the resist intermediate film or the inorganic hard mask intermediate film of the transferred pattern as a mask, transfer the pattern to the lower resist film by dry etching.

[0883] (V-10) Using the lower resist film of the transferred pattern as a mask, transfer the pattern to the stacked film of the insulating film and the conductive film by dry etching.

[0884] (V-11) Using the stacked film of the insulating film and the conductive film of the transferred pattern as a mask, remove the metal oxide film filled on the substrate to be processed.

[0885]

[16] : According to the pattern forming method of any one of claims 11 to 15, use a substrate having a structure or height difference with an aspect ratio of 5 or more as the substrate to be processed.

[0886]

[17] : A method for forming a metal oxide film, which is a method for forming a metal oxide film acting as a planarizing film used in the manufacturing process of a semiconductor device, characterized in that:

[0887] Heat-treat the substrate coated with the metal oxide film forming composition of any one of [1] to

[10] on the substrate to be processed at a temperature of 100 °C or more and 600 °C or less for 10 to 600 seconds to form a hardened film.

[0888]

[18] : A method for forming a metal oxide film, which is a method for forming a metal oxide film acting as a planarizing film used in the manufacturing process of a semiconductor device,

[0889] characterized in that heat-treat the substrate coated with the metal oxide film forming composition of any one of [1] to

[10] on the processed substrate in a gas environment with an oxygen concentration of 1 vol% or more and 21 vol% or less to form a hardened film.

[0890]

[19] : A method for forming a metal oxide film, which is a method for forming a metal oxide film acting as a planarizing film used in the manufacturing process of a semiconductor device,

[0891] characterized in that heat-treat the substrate coated with the metal oxide film forming composition of any one of [1] to

[10] on the substrate to be processed in a gas environment with an oxygen concentration of less than 1 vol% to form a hardened film.

[0892] Further, the present invention is not limited to the above embodiments. The above embodiments are illustrative, and those having substantially the same configuration as the technical idea described in the claims of the present invention and exhibiting the same effects are all included in the technical scope of the present invention.

[0893] Explanation of reference numerals

[0894] 1: Substrate to be processed

[0895] 2: Layer to be processed

[0896] 2a: Pattern (pattern formed on the layer to be processed)

[0897] 3: Metal-containing underlayer resist film (metal oxide film)

[0898] 3a: Metal-containing underlayer resist film pattern

[0899] 4: Silicon atom-containing intermediate resist film

[0900] 4a: Silicon atom-containing intermediate resist film pattern

[0901] 5: Upper resist film

[0902] 5a: Upper resist film pattern

[0903] 6: Exposed part

[0904] 7: Underlayer resist film composed of a coating-type organic underlayer film material

[0905] 7a: Underlayer resist film pattern composed of a coating-type organic underlayer film material

[0906] 8: Metal oxide film

[0907] 8a: Metal oxide film pattern formed by inverting the underlayer resist film pattern

[0908] 9: Conductive film

[0909] 9a: Conductive film pattern

[0910] 10: Insulating film

[0911] 10a: Insulating film pattern

[0912] 11: Continuously upper and lower insulating film

[0913] 12: Metal oxide film

[0914] 12a: Metal oxide film after CMP planarization

[0915] 13: Organic underlayer resist film

[0916] 13a: Organic underlayer resist film pattern

[0917] 14: Silicon atom-containing intermediate resist film

[0918] 14a: Silicon atom-containing intermediate resist film pattern

[0919] 15: Upper resist film

[0920] 15a: Resist upper layer film pattern

[0921] 16: Through pattern between 100 - layer and 200 - layer

[0922] 100: Alternating stacked film of insulating film pattern 10a and conductive film pattern 9a (lower layer)

[0923] 200: Alternating stacked film of insulating film 10 and conductive film 9 (upper layer)

[0924] 17: Substrate with dense hole pattern

[0925] 18: Metal oxide film

Claims

1. A composition for forming a metal oxide film, characterized by comprising: (A) Metal oxide nanoparticles; (B) A fluidity promoter containing a resin having a structural unit represented by the following general formula (1), (C) A dispersion stabilizer composed of an aromatic compound containing two or more benzene rings, or one benzene ring and a structure represented by the following general formula (C-1) and having a molecular weight of 500 or less in terms of molecular formula, and (D) An organic solvent, The content of the (B) fluidity promoter relative to the whole composition is 9% by mass or more, the ratio Mw / Mn of the weight-average molecular weight Mw to the number-average molecular weight Mn measured by gel permeation chromatography is 2.50 ≤ Mw / Mn ≤ 9.00, and it does not contain compounds and polymers with a cardo structure, In the general formula (1), R a is a saturated monovalent organic group having 1 to 30 carbon atoms or an unsaturated monovalent organic group having 2 to 30 carbon atoms, X is a divalent organic group having 1 to 30 carbon atoms, p is an integer of 0 to 5, q 1 is an integer of 1 to 6, p + q 1 is an integer of 1 or more and 6 or less, q 2 is 0 or 1, In the formula, * represents the bonding position, and W is an organic group having 1 to 4 carbon atoms; The weight loss rate of the (C) dispersion stabilizer from 30 °C to 190 °C is less than 30%, and the weight loss rate between 30 °C and 350 °C is 98% or more.

2. The composition for forming a metal oxide film according to claim 1, wherein, The (B) fluidity promoter is a fluidity promoter containing a resin having a structural unit represented by the general formula (1) and further containing a resin having a structural unit represented by the following general formula (2), or is a resin having both the structural unit represented by the general formula (1) and the structural unit represented by the following general formula (2), In the general formula (2), R a is a saturated monovalent organic group having 1 to 30 carbon atoms or an unsaturated monovalent organic group having 2 to 30 carbon atoms, and R b is a saturated hydrocarbon group having 1 to 30 carbon atoms or an unsaturated hydrocarbon group having 2 to 10 carbon atoms, X is a divalent organic group having 1 to 30 carbon atoms, p is an integer from 0 to 5, q 1 is an integer from 1 to 6, p + q 1 is an integer of 1 or more and 6 or less, and q 2 is 0 or 1.

3. The composition for forming a metal oxide film according to claim 2, wherein, In the general formula (2), R b is an alkyl group having 1 to 30 carbon atoms or any one of the structures represented by the following general formula (3). When the proportion of the general formula (1) is a and the proportion of the general formula (2) is b, the content of the general formula (2) satisfies the relationship of a + b = 1 and 0.2 ≤ b ≤ 0.

8. In the general formula (3), * represents the bonding site to the oxygen atom, and R A is a divalent organic group having 1 to 10 carbon atoms which may also be substituted, and R B is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms which may also be substituted.

4. The composition for forming a metal oxide film according to claim 1, wherein, The (C) dispersion stabilizer contains one or more compounds selected from the following general formulas (I) to (III), In the formula, R 1 each independently represents a hydrogen atom, a hydroxyl group, or an organic group having 1 to 10 carbon atoms which may be substituted, and W 1 represents a phenylene group or a divalent group represented by the following general formula (I-1), and W 2 , W 3 represents a single bond or any divalent group represented by the following general formula (I-2), m 1 is an integer from 1 to 10, and n 1 is an integer from 0 to 5. In the formula, * represents the bonding position, and R 10 , R 11 , R 12 , R 13 is a hydrogen atom, a hydroxyl group, or an organic group having 1 to 10 carbon atoms. W 10 , W 11 each independently represents a single bond or a carbonyl group. m 10 , m 11 is an integer from 0 to 10, and m 10 + m 11 ≥ 1 In the formula, * represents the bonding position, In the formula, R 2 each independently represents a hydrogen atom or an optionally substituted organic group having 1 to 10 carbon atoms, and W 4 represents any divalent group represented by the following general formula (II-1), and W 5 represents a single bond or a divalent group represented by the following general formula (II-2), and m 2 is an integer of 2 to 10, and n 3 is an integer of 0 to 5. In the formula, * represents the bonding position, and R 20 , R 21 , R 22 , R 23 is a hydrogen atom, a hydroxyl group, or an organic group having 1 to 10 carbon atoms, and m 20 , m 21 is an integer from 0 to 10, and m 20 + m 21 ≥ 1 In the formula, * represents the bonding position, In the formula, R 3 , R 4 is a hydrogen atom, a hydroxyl group, or an organic group having 1 to 10 carbon atoms which may be substituted, and may also be bonded to form a cyclic structure, R 5 , R 6 is an organic group having 1 to 10 carbon atoms, R 5 is a group containing an aromatic ring or any one of the divalent groups represented by the following general formula (III-1), W 6 , W 7 is a single bond or any one of the divalent groups represented by the following general formula (III-2), and at least one is a divalent group represented by the following general formula (III-2). In the formula, * represents the bonding position, and W 30 is an organic group having 1 to 4 carbon atoms, In the formula, * represents the bonding position.

5. The composition for forming a metal oxide film according to claim 1, wherein, The (A) metal oxide nanoparticles are one or more of metal oxide nanoparticles selected from the group consisting of zirconium, hafnium, aluminum, tungsten, titanium, copper, tin, cerium, indium, zinc, yttrium, lanthanum, chromium, cobalt, platinum, iron, antimony, and germanium.

6. The composition for forming a metal oxide film according to claim 5, wherein, The (A) metal oxide nanoparticles are one or more selected from the group consisting of zirconium oxide nanoparticles, hafnium oxide nanoparticles, tungsten oxide nanoparticles, titanium oxide nanoparticles, and tin oxide nanoparticles.

7. The composition for forming a metal oxide film according to claim 1, wherein, The (A) metal oxide nanoparticles have an average primary particle size of 100 nm or less.

8. The composition for forming a metal oxide film according to claim 1, wherein, The weight ratio of the (A) metal oxide nanoparticles to the (B) fluidity promoter is 80 / 20 to 10 / 90.

9. The composition for forming a metal oxide film according to claim 1, wherein, The composition for forming a metal oxide film further contains one or more of a crosslinking agent, a surfactant, and an acid generator.

10. A pattern forming method, which is a method for forming a pattern on a substrate to be processed, characterized by including the following steps: (I-1) After coating the composition for forming a metal oxide film according to Claim 1 on the substrate to be processed, performing heat treatment to form a metal oxide film, (I-2) Forming a resist upper layer film on the metal oxide film using a photoresist material, (I-3) After subjecting the resist upper layer film to pattern exposure, developing it with a developer to form a pattern on the resist upper layer film, (I-4) Using the patterned resist upper layer film as a mask, transferring the pattern to the metal oxide film by dry etching, and (I-5) Using the patterned metal oxide film as a mask, processing the substrate to be processed to form a pattern on the substrate to be processed.

11. A pattern forming method, which is a method for forming a pattern on a substrate to be processed ， characterized by including the following steps: (II-1) Coating on the substrate to be processed After the composition for forming a metal oxide film according to Claim 1, performing heat treatment to form a metal oxide film, (II-2) Forming a silicon-containing resist intermediate film on the metal oxide film using a silicon-containing resist intermediate film material, (II-3) Forming a resist upper layer film on the silicon-containing resist intermediate film using a photoresist material, (II-4) After subjecting the resist upper layer film to pattern exposure, developing it with a developer to form a pattern on the resist upper layer film, (II-5) Using the patterned resist upper layer film as a mask, transferring the pattern to the silicon-containing resist intermediate film by dry etching, (II-6) Using the silicon-containing resist intermediate film with the transferred pattern as a mask, transferring the pattern to the metal oxide film by dry etching step, and (II-7) Using the patterned metal oxide film as a mask, processing the substrate to be processed to form a pattern on the substrate to be processed.

12. A pattern forming method, which is a method for forming a pattern on a substrate to be processed ， characterized by including the following steps: (III-1) Coating on the substrate to be processed After the composition for forming a metal oxide film according to Claim 1, performing heat treatment to form a metal oxide film, (III-2) Forming an inorganic hard mask intermediate film selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film on the metal oxide film, (III-3) Forming an organic thin film on the inorganic hard mask intermediate film, (III-4) Forming a resist upper layer film on the organic thin film using a photoresist material, (III-5) After subjecting the resist upper layer film to pattern exposure, developing it with a developer to form a pattern on the resist upper layer film, (III-6) Using the patterned resist upper layer film as a mask, transferring the pattern to the organic thin film and the inorganic hard mask intermediate film by dry etching, (III-7) Using the inorganic hard mask intermediate film with the transferred pattern as a mask, transferring the pattern to the metal oxide film by dry etching step, and (III-8) Using the patterned metal oxide film as a mask, processing the substrate to be processed to form a pattern on the substrate to be processed.

13. A pattern forming method is a method for forming a pattern on a substrate to be processed. ， It is characterized by including the following steps: (IV-1) Forming an underlayer resist film on the substrate to be processed. (IV-2) Forming an intermediate resist film on the underlayer resist film, or a combination of an inorganic hard mask intermediate film selected from silicon oxide films, silicon nitride films, and silicon oxynitride films and an organic thin film. (IV-3) Using a photoresist material to form an upper layer resist film on the intermediate resist film, or the combination of the inorganic hard mask intermediate film and the organic thin film. (IV-4) After subjecting the upper layer resist film to pattern exposure, developing it with a developer to form a pattern on the upper layer resist film. (IV-5) Using the patterned upper layer resist film as a mask, transferring the pattern to the intermediate resist film, or the organic thin film and the inorganic hard mask intermediate film by dry etching. (IV-6) Using the patterned intermediate resist film, or the inorganic hard mask intermediate film as a mask, transferring the pattern to the underlayer resist film by dry etching. (IV-7) Coating on the patterned underlayer resist film After coating the composition for forming a metal oxide film according to claim 1, performing heat treatment to coat a metal oxide film, and filling the spaces between the patterns of the underlayer resist film with the metal oxide film. (IV-8) Etching back the metal oxide film coated on the patterned underlayer resist film by chemical stripping or dry etching to expose the top surface of the patterned underlayer resist film. (IV-9) Removing the remaining intermediate resist film, or the inorganic hard mask intermediate film on the top surface of the underlayer resist film by dry etching. (IV-10) Removing the exposed surface of the patterned underlayer resist film by dry etching to form an inverted pattern of the original pattern on the metal oxide film. (IV-11) Using the metal oxide film with the inverted pattern formed as a mask, processing the substrate to be processed to form a tone-inverted pattern on the substrate to be processed.

14. A pattern forming method is a pattern forming method for a sacrificial film using a composition for forming a metal oxide film, which is characterized by including the following steps: (V-1) After coating the composition for forming a metal oxide film according to claim 1 on a substrate to be processed having a structure or height difference, performing heat treatment to fill the metal oxide film. (V-2) Removing the metal oxide film outside the structure or height difference on the substrate to be processed by CMP method, and removing the metal oxide film from the surface of the substrate to be processed. (V-3) Alternately laminating an insulating film and a conductive film on the substrate to be processed filled with the metal oxide film. (V-4) Forming an organic underlayer resist film on the laminated film of the insulating film and the conductive film formed on the substrate to be processed filled with the metal oxide film. (V-5) Forming an intermediate resist film on the organic underlayer resist film, or an inorganic hard mask intermediate film selected from silicon oxide films, silicon nitride films, and silicon oxynitride films, or a combination of the inorganic hard mask intermediate film and an organic thin film. (V-6) On the resist intermediate film, or the inorganic hard mask intermediate film, or a combination of the inorganic hard mask intermediate film and the organic film, a resist upper layer film is formed using a photoresist material. (V-7) After pattern exposure of the resist upper layer film, development is performed with a developer to form a pattern in the resist upper layer film. (V-8) Using the patterned resist upper layer film as a mask, the pattern is transferred to the resist intermediate film, or the inorganic hard mask intermediate film, or the organic film and the inorganic hard mask intermediate film by dry etching. (V-9) Using the resist intermediate film or the inorganic hard mask intermediate film with the transferred pattern as a mask, the pattern is transferred to the resist lower layer film by dry etching. (V-10) Using the resist lower layer film with the transferred pattern as a mask, the pattern is transferred to the stacked film of the insulating film and the conductive film by dry etching. (V-11) Using the stacked film of the insulating film and the conductive film with the transferred pattern as a mask, the metal oxide film filled on the processed substrate is removed.

15. The pattern forming method according to any one of claims 10 to 14, wherein a substrate having a structure with an aspect ratio of 5 or more or a height difference is used as the processed substrate.

16. A method for forming a metal oxide film, which is a method for forming a metal oxide film acting as a planarizing film used in the manufacturing process of a semiconductor device. Characterized in that: The substrate coated with the composition for forming a metal oxide film according to any one of claims 1 to 9 on the processed substrate is heat-treated at a temperature of 100 °C or higher and 600 °C or lower for 10 to 600 seconds to form a hardened film.

17. A method for forming a metal oxide film, which is a method for forming a metal oxide film acting as a planarizing film used in the manufacturing process of a semiconductor device. Characterized in that the substrate coated with the composition for forming a metal oxide film according to any one of claims 1 to 9 on the processed substrate is heat-treated in a gas environment with an oxygen concentration of 1 vol% or more and 21 vol% or less to form a hardened film.

18. A method for forming a metal oxide film, which is a method for forming a metal oxide film acting as a planarizing film used in the manufacturing process of a semiconductor device. Characterized in that the substrate coated with the composition for forming a metal oxide film according to any one of claims 1 to 9 on the processed substrate is heat-treated in a gas environment with an oxygen concentration of less than 1 vol% to form a hardened film.

Images