Metal-containing film-forming compound, metal-containing film-forming composition, and pattern formation method

Abstract

To provide a metal-containing film-forming compound that provides a resist intermediate film capable of obtaining a good pattern profile in a fine patterning process in semiconductor device fabrication step, exhibiting high adhesion to a resist upper layer and preventing collapse of fine patterns, as well as a metal-containing film-forming composition using the compound and a pattern formation method using the composition.SOLUTION: A metal-containing film-forming compound includes at least one metal atom selected from the group consisting of Ti, Zr, and Hf, and a ligand coordinated to the metal atom via an oxygen atom, and the ligand has a ring structure (t) selected from a ring having 4 or more carbon atoms and containing one or more oxygen atoms, a ring having 3 or more carbon atoms and containing two or more oxygen atoms, and a ring having 3 or more carbon atoms and containing one or more oxygen atoms and one or more hetero atoms different from oxygen atoms.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a compound for forming a metal-containing film, a composition for forming a metal-containing film using the compound, and a pattern formation method using the composition. [Background technology]

[0002] As LSIs become more highly integrated and faster, pattern dimensions are becoming increasingly fine. Lithography technology has achieved this by shortening the wavelength of light sources and selecting appropriate resist compositions to match. Single-layer positive photoresist compositions have become the key to this. These single-layer positive photoresist compositions incorporate a backbone that provides etching resistance to dry etching with chlorine- or fluorine-based gas plasma, and a switching mechanism that dissolves exposed areas. This allows the exposed areas to be dissolved to form a pattern, and the remaining resist pattern is then used as an etching mask to dry etch the substrate.

[0003] However, if the thickness of the photoresist film used is made finer, i.e., the pattern width is made smaller, the resolution of the photoresist film decreases, and when an attempt is made to develop the photoresist film into a pattern using a developer, the aspect ratio becomes too large, resulting in pattern collapse. For this reason, photoresist films have been made thinner as patterns become finer.

[0004] On the other hand, substrate processing typically involves dry etching using a patterned photoresist film as an etching mask. However, in reality, no dry etching method can achieve perfect etching selectivity between the photoresist film and the substrate. As a result, the photoresist film can be damaged and disintegrated during substrate processing, preventing accurate transfer of the resist pattern to the substrate. Therefore, as patterns become finer, resist compositions are required to have higher dry etching resistance. However, to improve resolution, resins used in photoresist compositions must have low light absorption at the exposure wavelength. As a result, as exposure light wavelengths have become shorter (i-line, KrF, and ArF), resins have evolved, such as novolac resins, polyhydroxystyrenes, and resins with aliphatic polycyclic skeletons. However, in reality, the etching rates under dry etching conditions during substrate processing have become faster, and recent photoresist compositions with high resolution tend to have weaker etching resistance.

[0005] This means that substrates to be processed must be dry etched using thinner photoresist films with weaker etching resistance, and there is an urgent need to secure the materials and processes required for this processing step.

[0006] One method for solving these problems is the multilayer resist method, in which a resist intermediate film having an etching selectivity different from that of a photoresist film (i.e., a resist upper layer film) is interposed between the resist upper layer film and the substrate to be processed, a pattern is formed on the resist upper layer film, and then the pattern is transferred to the resist intermediate film by dry etching using the resist upper layer film pattern as a dry etching mask, and the pattern is further transferred to the substrate to be processed by dry etching using the resist intermediate film as a dry etching mask.

[0007] One type of multilayer resist method is the three-layer resist method, which can be performed using a typical resist composition used in single-layer resist methods. In this three-layer resist method, for example, an organic film made of a novolac resin or the like is deposited on a substrate to be processed as a resist underlayer, a silicon-containing resist intermediate film is deposited on top of that as a resist intermediate film, and a conventional organic photoresist film is deposited on top of that as a resist upper layer. When dry etching is performed using a fluorine-based gas plasma, the organic resist upper layer exhibits a favorable etching selectivity relative to the silicon-containing resist intermediate film, allowing the resist upper layer pattern to be transferred to the silicon-containing resist intermediate film by dry etching with a fluorine-based gas plasma. This method allows for pattern transfer to the silicon-containing resist intermediate film (resist intermediate film) even when using a resist composition that is difficult to directly form a pattern with a sufficient thickness for processing the substrate or that does not have sufficient dry etching resistance for substrate processing. Subsequent pattern transfer by dry etching with an oxygen- or hydrogen-based gas plasma allows for the formation of a pattern in an organic film (resist underlayer) made of a novolac resin or the like that has sufficient dry etching resistance for substrate processing. Many of the above-mentioned resist underlayer films are already known, such as those described in Patent Document 1.

[0008] The silicon-containing resist intermediate film used in the three-layer resist method described above includes silicon-containing inorganic films prepared by CVD, such as SiO2 films (e.g., Patent Document 2) and SiON films (e.g., Patent Document 3), and films obtained by spin coating include SOG (spin-on-glass) films (e.g., Patent Document 4 and Non-Patent Document 1) and cross-linked silsesquioxane films (e.g., Patent Document 5). Polysilane films (e.g., Patent Document 6) may also be used. Among these, SiO2 films and SiON films have high performance as dry etching masks when dry etching the underlying organic film, but require special equipment for film formation. In contrast, SOG films, cross-linked silsesquioxane films, and polysilane films can be formed simply by spin coating and heating, and are considered to have high process efficiency.

[0009] The silicon-containing films traditionally used in multilayer resist processes have several problems. For example, when attempting to form resist patterns using optical lithography, it is well known that exposure light reflects off the substrate and interferes with the incident light, resulting in the so-called standing wave problem. Therefore, to obtain fine patterns without edge roughness in resist films under cutting-edge ArF immersion and high-NA exposure conditions, anti-reflective properties are essential for the interlayer. Furthermore, as photoresists become thinner in cutting-edge semiconductor processes, thinner interlayers are also required. Next-generation exposure processes require anti-reflective properties at thicknesses of 30 nm or less. Furthermore, the dry etching rate with oxygen gas plasma, which is commonly used to process resist underlayers, should be low to increase the etching selectivity between the interlayer and underlayer films. This trend toward thinner films necessitates improved dry etching resistance for interlayers.

[0010] Metal hard mask films containing Ti or Zr have been attracting attention as a resist intermediate film that satisfies these requirements for anti-reflection effect and dry etching properties, replacing conventional silicon-containing films. TiO2 and ZrO2 are known as high refractive index materials, and including them in the film can improve anti-reflection effect under high NA exposure conditions. In addition, the inclusion of metal-oxygen bonds is expected to provide excellent dry etching resistance to oxygen gas.

[0011] Furthermore, because metal hard mask films have excellent dry etching resistance not only to oxygen gas but also to fluorine gas, they are also promising candidates for a two-layer resist method in which a metal hard mask film is deposited on the substrate to be processed as a resist underlayer, and then a resist overlayer is formed on top of that.

[0012] However, when such a metal hard mask film is used directly under a resist top layer, improving adhesion to the resist pattern becomes an issue. The cured metal hard mask film has a much higher surface energy (or a lower water contact angle) than the subsequently applied photoresist. This surface energy mismatch can cause poor adhesion between the metal hard mask film and the subsequently applied photoresist, resulting in pattern collapse.

[0013] To prevent photoresist pattern collapse on a metal hard mask film, surface modification of the metal hard mask film is necessary. For example, Patent Document 7 reports a metal hard mask containing a surface-modified organic polymer. It has been reported that the difference in free energy between the organic polymer and the metal compound can be exploited to unevenly distribute the organic polymer on the surface, thereby improving adhesion to the resist pattern. To prevent pattern collapse, organic polymers containing surface-treated moieties selected from hydroxyl, protected hydroxyl, protected carboxyl, and mixtures thereof have been used. However, given the current demand for finer pattern formation, these materials are not sufficient in preventing pattern collapse. Furthermore, the inclusion of an organic polymer may reduce dry etching resistance to oxygen gas, so there is a need for the development of a compound for forming a metal-containing film that has excellent adhesion to the resist overlayer film.

[0014] Recently, it has been reported that the interaction at the interface between the resist top layer and the underlying layer directly below the resist top layer in a fine pattern affects the resist sensitivity, pattern shape (rectangularity and space residues), etc., and from these perspectives as well, there is a demand for improved performance of the underlying layer directly below the resist top layer (Non-Patent Document 2). [Prior art documents] [Patent documents]

[0015] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-205685 [Patent Document 2] Japanese Patent Application Publication No. 7-183194 [Patent Document 3] Japanese Patent Application Publication No. 7-181688 [Patent Document 4] Japanese Patent Application Publication No. 5-291208 [Patent Document 5] Special Publication No. 2005-520354 [Patent Document 6] Japanese Patent Application Publication No. 11-60735 [Patent Document 7] Patent Publication No. 6463600 [Non-patent literature]

[0016] [Non-Patent Document 1] J.Appl.Polym. Sci.,Vol.88,636-640(2003) [Non-patent document 2] Proc. SPIE Vol. 7273,72731J(2009) Summary of the Invention [Problem to be solved by the invention]

[0017] The present invention has been made in view of the above circumstances, and aims to provide a metal-containing forming compound that can obtain a good pattern shape in a fine patterning process in a semiconductor device manufacturing process and that can provide a resist intermediate film that has high adhesion to a resist upper layer film and prevents collapse of the fine pattern, a metal-containing forming composition using the compound, and a pattern forming method using the composition. [Means for solving the problem]

[0018] In order to solve the above problems, the present invention provides: A metal-containing film-forming compound, the metal-containing film-forming compound contains at least one metal atom selected from the group consisting of Ti, Zr, and Hf, and a ligand coordinated to the metal atom via an oxygen atom; The ligand is a ring having 4 or more carbon atoms and containing one or more oxygen atoms; a ring having 3 or more carbon atoms and containing 2 or more oxygen atoms, and A ring with 3 or more carbon atoms containing one or more oxygen atoms and one or more heteroatoms different from oxygen atoms The present invention provides a compound for forming a metal-containing film, which has a ring structure (t) selected from the following:

[0019] When such a compound for forming a metal-containing film is used in a composition for forming a metal-containing film, it is possible to improve adhesion to a resist upper layer film and to form a resist pattern having a rectangular shape after exposure and development, thereby enabling substrate processing with fine patterns.

[0020] The ring structure (t) is preferably a structure containing a ring having 4 or more carbon atoms and containing two or more oxygen atoms, or a structure containing a ring having 4 or more carbon atoms and one or more oxygen atoms and one or more heteroatoms different from oxygen atoms.

[0021] When such a compound for forming a metal-containing film is used in a composition for forming a metal-containing film, it is possible to further improve adhesion to a resist upper layer film and to form a resist pattern having a rectangular shape after exposure and development, thereby enabling substrate processing with fine patterns.

[0022] The ring structure (t) is preferably one that is bonded to one or more of a cyclic hydrocarbon having 4 to 6 carbon atoms and optionally containing a heteroatom, a cyclic hydrocarbon having 5 to 6 carbon atoms and optionally containing a heteroatom having one or more carbon-carbon double bonds, an aromatic ring, or an aromatic heterocycle to form a polycyclic structure.

[0023] When such a compound for forming a metal-containing film is used in a composition for forming a metal-containing film, it is possible to improve heat resistance, further improve adhesion to a resist upper layer film, and form a resist pattern having a rectangular shape after exposure and development, thereby enabling substrate processing with fine patterns.

[0024] The ring structure (t) is preferably derived from an organic acid containing the ring structure (t).

[0025] Such a ligand exhibits a strong coordination effect on metal atoms, and when used in a metal-containing film-forming composition, a composition with excellent storage stability can be provided.

[0026] The organic acid is preferably derived from a carboxylic acid.

[0027] Such a ligand exhibits a strong coordination effect to metal atoms, and therefore, when used in a metal-containing film-forming composition, a composition with excellent storage stability can be provided. This is also preferable from the viewpoint of raw material availability.

[0028] The ligand is preferably derived from the following structure:

[0029] [ka] (In the formula, Ra is a monovalent organic group containing the ring structure (t), X is a group selected from a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, a substituted or unsubstituted branched alkylene group having 3 to 10 carbon atoms, a substituted or unsubstituted alkylene group having 2 to 10 carbon atoms and containing a carbon-carbon double bond, and a substituted or unsubstituted branched alkylene group having 3 to 10 carbon atoms and containing a carbon-carbon double bond, and n is 0 or 1.)

[0030] When such a compound for forming a metal-containing film is used in a composition for forming a metal-containing film, it is possible to further improve adhesion to a resist upper layer film and to form a resist pattern having a rectangular shape after exposure and development, thereby enabling substrate processing with fine patterns.

[0031] It is preferable that the compound for forming a metal film further contains a ligand derived from a silicon compound represented by the following general formula (w). [ka] (In the formula, R A , R B and R C is any organic group selected from an organic group having 2 to 30 carbon atoms and a crosslinking group having any of the structures represented by the following general formulas (w-1) to (w-3), a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, and an aryl group having 6 to 20 carbon atoms. [ka] (In the above general formulae (w-1) to (w-3), Rs represents a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, q represents 0 or 1, and * represents a bond.)

[0032] When the compound further contains a ligand derived from the silicon compound represented by the general formula (w), the stability of the metal compound in solution can be improved.

[0033] The compound for forming a metal-containing film is preferably a reaction product of a metal compound represented by the following formula (a) or a metal-containing compound containing any one of a hydrolysate, a condensate, and a hydrolysis condensate of the metal compound represented by the following formula (a) with a compound having the ring structure (t): [ka] (wherein M is any one of Ti, Zr, and Hf; L is a monodentate or polydentate ligand having 1 to 30 carbon atoms; X is a halogen atom, an alkoxy group, a carboxylate group, an acyloxy group, or —NR 1 R 2 R is a hydrolyzable group selected from 1 and R 2 are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms; a+b=2 to 4, and a and b are integers of 0 to 4.

[0034] By using such a metal compound, a metal-containing film having excellent resistance to dry etching with fluorine gas and oxygen gas can be formed.

[0035] The formula (a) preferably has a structure of the following formula (a-1). [ka] (Wherein, M is any one of Ti, Zr, and Hf; R 1A is a monovalent organic group having 1 to 20 carbon atoms.

[0036] A metal compound having such a structure is preferable from the viewpoints of productivity and availability of raw materials.

[0037] The present invention also provides a metal-containing film-forming composition that functions as a metal-containing film material used in semiconductor manufacturing, the metal-containing film-forming composition containing the above-described (A) metal-containing film-forming compound and (B) organic solvent.

[0038] Such a composition for forming a metal-containing film can form a metal-containing film that has excellent dry etching resistance compared to conventional resist underlayer film materials and also has excellent wet strippability.

[0039] The composition may further contain one or more of (C) a crosslinking agent, (D) an acid generator, and (E) a surfactant.

[0040] A metal-containing film-forming composition containing the above additives will have better coatability, dry etching resistance, and filling and / or planarization properties.

[0041] The (B) organic solvent preferably contains, as the (B1) high boiling point solvent, one or more organic solvents having a boiling point of 180° C. or higher.

[0042] By adding a high-boiling point solvent to the metal-containing film-forming compound, fluidity is imparted, thereby making it possible to suppress the occurrence of coating defects caused by drying of the metal-containing film-forming composition.

[0043] The present invention also provides a method for forming a pattern on a substrate to be processed, comprising the steps of: (I-1) a step of directly or indirectly applying the metal-containing film-forming composition of the present invention onto a substrate to be processed, followed by heat treatment to form a metal-containing film; (I-2) forming a resist top layer film directly or indirectly on the metal-containing film using a photoresist material; (I-3) a step of pattern-exposing the resist upper layer film and then developing it with a developer to form a pattern on the resist upper layer film; (I-4) a step of transferring the pattern to the metal-containing film directly or indirectly by dry etching using the resist upper layer film on which the pattern has been formed as a mask; and (I-5) A step of directly or indirectly processing the substrate to be processed using the metal-containing film on which the pattern has been formed as a mask to form a pattern on the substrate to be processed. The present invention provides a pattern forming method comprising the steps of:

[0044] Such a pattern forming method can be suitably used in a pattern forming method such as a multilayer resist process.

[0045] The pattern forming method of the present invention may further include at least one organic resist underlayer film between the substrate to be processed and the metal-containing film.

[0046] Such a pattern forming method makes it possible to transfer a pattern onto a substrate to be processed with high precision.

[0047] In the pattern forming method of the present invention, it is preferable to form a resist upper layer film directly on the metal-containing film.

[0048] A metal-containing film formed using the compound for forming a metal-containing film of the present invention has excellent adhesion to a resist upper layer film, and therefore a resist upper layer film pattern with high rectangularity can be obtained.

[0049] The pattern formation method of the present invention may further include a step of removing the metal-containing film with a chemical solution after a step of forming a pattern by processing a film directly below the metal-containing film using the metal-containing film as a mask.

[0050] Such a pattern formation method makes it possible to easily remove the metal-containing film while minimizing damage to the substrate, and therefore makes it possible to form a pattern with excellent rectangular cross-sectional shape.

[0051] The chemical solution is preferably a solution containing hydrogen peroxide and an acid, or a solution containing a base, hydrogen peroxide, and water.

[0052] Such a chemical solution can easily remove a metal-containing film formed using the compound for forming a metal-containing film of the present invention. [Effects of the Invention]

[0053] As described above, the metal-containing film-forming compound of the present invention contains a ligand having a specific ring structure (t), and therefore, when a metal-containing film is formed using this compound, adhesion to the resist overlying film can be improved, and the resist pattern obtained after exposure and development has a rectangular shape. Therefore, a metal-containing film-forming composition using the metal-containing film-forming compound and a pattern formation method using this composition can be suitably used in pattern formation methods such as multilayer resist processes. [Brief explanation of the drawings]

[0054] [Figure 1] FIG. 1 is an explanatory diagram of an example of the pattern forming method of the present invention (three-layer resist process). [Figure 2] FIG. 2 is an explanatory diagram of an example of a pattern formation method (three-layer resist process) using wet peeling according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0055] As described above, there has been a need for the development of a metal-containing film-forming compound that has high adhesion to a resist overcoat film and is effective in preventing collapse of a fine pattern, a metal-containing film-forming composition using the compound, and a pattern formation method using the composition.

[0056] Since metal-containing films formed using conventional metal-containing film-forming compounds have a much higher surface energy (or a lower water contact angle) than the subsequently applied photoresist, this surface energy mismatch can cause poor adhesion between the metal-containing film and the subsequently applied photoresist, resulting in pattern collapse. Furthermore, when an organic polymer is mixed as a surface modifier, the dry etching resistance during processing of the organic underlayer film can be insufficient, potentially leading to poor pattern transfer.

[0057] As a result of extensive research into the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by a compound for forming a metal-containing film containing a ligand of a specific structure, a composition for forming a metal-containing film using the compound, and a pattern formation method using the composition, and have thus completed the present invention.

[0058] That is, the present invention provides: A metal-containing film-forming compound, the metal-containing film-forming compound contains at least one metal atom selected from the group consisting of Ti, Zr, and Hf, and a ligand coordinated to the metal atom via an oxygen atom; The ligand is a ring having 4 or more carbon atoms and containing one or more oxygen atoms; a ring having 3 or more carbon atoms and containing 2 or more oxygen atoms, and A ring with 3 or more carbon atoms containing one or more oxygen atoms and one or more heteroatoms different from oxygen atoms The compound for forming a metal-containing film has a ring structure (t) selected from the following:

[0059] The present invention will be described in detail below, but the present invention is not limited thereto.

[0060] <Compounds for forming metal-containing films> The present invention provides a compound for forming a metal-containing film, the metal-containing film-forming compound contains at least one metal atom selected from the group consisting of Ti, Zr, and Hf, and a ligand coordinated to the metal atom via an oxygen atom; The ligand is a ring having 4 or more carbon atoms and containing one or more oxygen atoms; a ring having 3 or more carbon atoms and containing 2 or more oxygen atoms, and A ring with 3 or more carbon atoms containing one or more oxygen atoms and one or more heteroatoms different from oxygen atoms The compound for forming a metal-containing film has a ring structure (t) selected from the following:

[0061] Here, in the ring structure (t), the number of carbon atoms in a ring containing one or more oxygen atoms and having 4 or more carbon atoms refers to the number of carbon atoms that directly contribute to the formation of one ring structure containing an oxygen atom, and does not include the number of carbon atoms that contribute to the formation of an adjacent ring structure.

[0062] The ring structure (t) is a structure selected from a ring having 4 or more carbon atoms and containing one or more oxygen atoms, a ring having 3 or more carbon atoms and containing two or more oxygen atoms, and a ring having 3 or more carbon atoms and containing one or more oxygen atoms and one or more heteroatoms other than the oxygen atoms, and is more preferably a ring structure having 4 to 6 carbon atoms. The ring structure may have one or more unsaturated bonds, or may be a ring structure corresponding to a heterocyclic aromatic ring. Such a ring structure is preferable because it can provide a metal compound having excellent storage stability in the composition.

[0063] When such a metal compound is used in a composition for forming a metal-containing film, it is possible to form a metal-containing film that has superior dry etching resistance compared to conventional resist underlayer film materials and has excellent adhesion to the resist upper layer film.

[0064] Preferred examples of the ring structure (t) include the following.

[0065] [ka]

[0066] The ligand has a ring structure (t) selected from a ring having 4 or more carbon atoms and containing one or more oxygen atoms, a ring having 3 or more carbon atoms and containing one or more oxygen atoms and one or more heteroatoms other than the oxygen atoms, and preferably has a ring structure having two or more oxygen atoms, or a ring structure (t-1) containing one or more oxygen atoms and one or more heteroatoms other than the oxygen atoms. That is, the ring structure (t) is preferably a structure containing a ring having 4 or more carbon atoms and containing two or more oxygen atoms, or a ring having 4 or more carbon atoms and containing one or more oxygen atoms and one or more heteroatoms other than the oxygen atoms.

[0067] When the ligand contains the ring structure (t-1), adhesion to the resist upper layer film can be further improved, and an excellent resist pattern shape can be formed when developed with an alkaline developer or an organic developer, and a rectangular resist pattern can be transferred to the lower layer by subsequent dry etching. The heteroatom other than the oxygen atom is not particularly limited as long as it is other than an oxygen atom, but a nitrogen atom or a sulfur atom is preferred, and a nitrogen atom is more preferred.

[0068] The ring structure (t) preferably forms a polycyclic structure by bonding with one or more of a cyclic hydrocarbon having 4 to 6 carbon atoms and optionally containing a heteroatom, a cyclic hydrocarbon having 5 to 6 carbon atoms and optionally containing a heteroatom having one or more carbon-carbon double bonds, an aromatic ring, or an aromatic heterocycle. Examples of the polycyclic structure include a fused ring, a bicyclic ring, a tricyclic ring, a fused ring containing a bridged structure, a fused ring containing a bridged ring containing a heteroatom, and a spiro ring.

[0069] When the ligand contains a polycyclic structure, heat resistance is improved, and adhesion to the resist upper layer film can be further improved.

[0070] The polycyclic structure preferably does not contain an acid anhydride unit, which prevents the acid anhydride structure from ring-opening and coordinating with a metal atom during synthesis of a metal compound, thereby preventing problems with adhesion to an upper resist film when used in a metal-containing film-forming composition.

[0071] The ligand is preferably derived from an organic acid. That is, the ring structure (t) is preferably derived from an organic acid containing the ring structure (t). The organic acid is preferably any one of carboxylic acid, sulfonic acid, phosphinic acid, and phosphonic acid, and is more preferably carboxylic acid from the viewpoint of coordination effect to metal atoms and availability of raw materials, and more specifically, is preferably derived from the following structure: [ka] (In the above formula, Ra is a monovalent organic group containing the ring structure (t), X is a group selected from a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, a substituted or unsubstituted branched alkylene group having 3 to 10 carbon atoms, a substituted or unsubstituted alkylene group having 2 to 10 carbon atoms and containing a carbon-carbon double bond, and a substituted or unsubstituted branched alkylene group having 3 to 10 carbon atoms and containing a carbon-carbon double bond, and n is 0 or 1.)

[0072] In the above formula (1), X is a group selected from a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, a substituted or unsubstituted branched alkylene group having 3 to 10 carbon atoms, a substituted or unsubstituted alkyl group having 2 to 10 carbon atoms and containing a carbon-carbon double bond, and a substituted or unsubstituted branched alkyl group having 3 to 10 carbon atoms and containing a carbon-carbon double bond, and is preferably a substituted or unsubstituted linear alkylene group having 1 to 10 carbon atoms or a substituted or unsubstituted alkylene group having 2 to 10 carbon atoms and containing a carbon-carbon double bond, and more preferably an unsubstituted alkylene group having 1 to 5 carbon atoms.

[0073] A preferred structure of Ra in the above formula (1) can be shown below. [ka] (The * above indicates the bond to X.)

[0074] From the viewpoint of raw material availability, n is preferably 0 in the above formula (1).

[0075] The compound for forming a metal-containing film is preferably a reaction product of a metal compound represented by the following formula (a) or a metal-containing compound containing any one of a hydrolysate, a condensate, and a hydrolysis condensate of the metal compound represented by the following formula (a) with a compound having the ring structure (t): [ka] (wherein M is any one of Ti, Zr, and Hf; L is a monodentate or polydentate ligand having 1 to 30 carbon atoms; X is a halogen atom, an alkoxy group, a carboxylate group, an acyloxy group, or —NR 1 R 2 R is a hydrolyzable group selected from 1 and R 2 are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms; a+b=2 to 4, and a and b are integers of 0 to 4.

[0076] When such a compound for forming a metal-containing film is used in a composition for forming a metal-containing film, a metal-containing film having excellent resistance to dry etching with fluorine gas and oxygen gas can be formed.

[0077] [(a) Metal-containing compound] (hydrolyzable group) Examples of the hydrolyzable group X in the above formula (a) include a halogen atom, an alkoxy group, a carboxylate group, an acyloxy group, and —NR 1 R 2 Examples include: R 1 and R 2 are preferably each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms.

[0078] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0079] Examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, and a t-butoxy group.

[0080] Examples of the carboxylate group include an acetate group, a propionate group, a butyrate group, an n-hexanecarboxylate group, and an n-octanecarboxylate group.

[0081] Examples of the acyloxy group include an acetoxy group, an ethyryloxy group, a propionyloxy group, a butyryloxy group, a t-butyryloxy group, a t-amylyloxy group, an n-hexanecarbonyloxy group, and an n-octanecarbonyloxy group.

[0082] Above -NR 1 R 2 Examples of the amino group include an unsubstituted amino group, a methylamino group, a dimethylamino group, a diethylamino group, and a dipropylamino group.

[0083] The hydrolyzable group X is preferably an alkoxy group, more preferably an i-propoxy group, an n-butoxy group, or a t-butoxy group.

[0084] (monodentate ligand) Examples of the monodentate ligand include a hydroxo ligand, a carboxy ligand, an amide ligand, an amine ligand, an ammonia ligand, and an olefin ligand.

[0085] Examples of the amide ligand include an unsubstituted amide ligand (NH2), a methylamide ligand (NHMe), a dimethylamide ligand (NMe2), a diethylamide ligand (NEt2), and a dipropylamide ligand (NPr2).

[0086] Examples of the amine ligand include pyridine, trimethylamine ligand, and piperidine ligand.

[0087] Examples of the olefin ligand include chain olefins such as ethylene and propylene, and cyclic olefins such as cyclopentene, cyclohexene and norbornene.

[0088] (polydentate ligand) Examples of the polydentate ligand include a ligand derived from a hydroxy acid ester, a ligand derived from a β-diketone, a ligand derived from a β-ketoester, a ligand derived from an α,α-dicarboxylic acid ester, a hydrocarbon having a π bond, and a diphosphine.

[0089] Examples of the hydroxy acid ester include glycolic acid ester, lactic acid ester, 2-hydroxycyclohexane-1-carboxylic acid ester, salicylic acid ester, and the like.

[0090] Examples of the β-diketone include acetoacetic ester, α-alkyl-substituted acetoacetic ester, β-ketopentanoic ester, benzoylacetic ester, and 1,3-acetonedicarboxylic ester.

[0091] Examples of the α,α-dicarboxylic acid ester include malonic acid diester, α-alkyl-substituted malonic acid diester, α-cycloalkyl-substituted malonic acid diester, and α-aryl-substituted malonic acid diester.

[0092] Examples of the hydrocarbon having a π bond include chain dienes such as butadiene and isoprene, cyclic dienes such as cyclopentadiene, methylcyclopentadiene, pentamethylcyclopentadiene, cyclohexadiene and norbornadiene, and aromatic hydrocarbons such as benzene, toluene, xylene, hexamethylbenzene, naphthalene and indene.

[0093] Examples of the diphosphines include 1,1-bis(diphenylphosphino)methane, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl, and 1,1′-bis(diphenylphosphino)ferrocene.

[0094] In the above general formula (a), a+b=2 to 4, and a and b are integers of 0 to 4. a is preferably 0 to 4, and more preferably 2 or 4. b is preferably 0 to 4, and more preferably 0, 2, or 4. By setting a and b within the above ranges, the stability of the metal-containing film-forming compound can be increased.

[0095] Preferred examples of the metal compound represented by formula (a) include the following.

[0096] Examples of titanium-containing compounds include diisopropoxybis(2,4-pentanedionato)titanium(IV), tetra-n-butoxytitanium(IV), tetra-n-propoxytitanium(IV), tetraisopropoxytitanium(IV), tri-n-butoxymonostearate titanium(IV), titanium(IV) butoxide oligomer, aminopropyltrimethoxytitanium(IV), triethoxymono(2,4-pentanedionato)titanium(IV), tri-n-propoxymono(2,4-pentanedionato)titanium(IV), triisopropoxymono(2,4-pentanedionato)titanium, and di-n-butoxybis(2,4-pentanedionato)titanium(IV).

[0097] Compounds containing zirconium include dibutoxybis(ethylacetoacetate)zirconium(IV), di-n-butoxybis(2,4-pentanedionato)zirconium(IV), tetra-n-butoxyzirconium(IV), tetra-n-propoxyzirconium(IV), tetraisopropoxyzirconium(IV), aminopropyltriethoxyzirconium(IV), 2-(3,4-epoxycyclohexyl)ethyltrimethoxyzirconium(IV), γ-glycidoxy ... Examples of suitable methoxyzirconium compounds include methoxyzirconium(IV), 3-isocyanopropyltrimethoxyzirconium(IV), triethoxymono(2,4-pentanedionato)zirconium(IV), tri-n-propoxymono(2,4-pentanedionato)zirconium(IV), triisopropoxymono(2,4-pentanedionato)zirconium(IV), tri(3-methacryloxypropyl)methoxyzirconium(IV), and tri(3-acryloxypropyl)methoxyzirconium(IV).

[0098] Examples of compounds containing hafnium include diisopropoxybis(2,4-pentanedionato)hafnium(IV), tetrabutoxyhafnium(IV), tetraisopropoxyhafnium(IV), tetraethoxyhafnium(IV), and dichlorobis(cyclopentadienyl)hafnium(IV).

[0099] Among the above, metal alkoxides, metal carboxylates, and metal acetates are more preferred, and from the viewpoint of raw material availability, a structure of the following formula (a-1) is even more preferred. [ka] (Wherein, M is any one of Ti, Zr, and Hf; R 1A is a monovalent organic group having 1 to 20 carbon atoms.

[0100] In the formula (a-1), R 1Arepresents a monovalent organic group having 1 to 20 carbon atoms, and is preferably a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, or a t-butyl group, and more preferably an isopropyl group, an n-butyl group, or a t-butyl group.

[0101] During the synthesis reaction of a compound for forming a metal-containing film, in addition to the (a) metal compound, a compound that can become a monodentate or polydentate ligand in the compound for forming a metal-containing film (hereinafter referred to as (b) ligand-forming compound) may be added.

[0102] Examples of the (b) ligand-forming compound include organic compounds derived from hydroxo ligands, carboxy ligands, amide ligands, amine ligands, ammonia ligands, olefin ligands, etc., which are listed as L in the general formula (a), organic compounds derived from ligands derived from hydroxy acid esters, ligands derived from β-diketones, ligands derived from β-ketoesters, ligands derived from α,α-dicarboxylic acid esters, etc., as well as compounds having compounds with multiple hydroxy groups.

[0103] In the metal-containing film-forming compound, the content of the ligand having the ring structure (t) is preferably 10 mol % to 90 mol %, more preferably 20 mol % to 80 mol %, and even more preferably 25 mol % to 75 mol % of the total ligands coordinated to the metal atom. The content of ligands other than the compound having the ring structure (t), such as (b) the ligand-forming compound and ligands derived from an alkoxy group having 1 to 10 carbon atoms, is preferably 0 mol % to 90 mol %, more preferably 20 mol % to 80 mol %, of the total ligands coordinated to the metal atom.

[0104] Furthermore, during the synthesis reaction of the metal-containing film-forming compound, (c) a silicon-containing compound may be added in addition to (b) the ligand-forming compound.

[0105] (a) By substituting the hydrolyzable group of the metal compound with a silicon-containing compound, the stability of the metal-containing film-forming compound in the metal-containing film-forming composition can be improved.

[0106] (c) Examples of the silicon-containing compound include a structure of the following formula (w): [ka] (In the formula, R A , R B and R C is any organic group selected from an organic group having 2 to 30 carbon atoms and a crosslinking group having any of the structures represented by the following general formulas (w-1) to (w-3), a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, and an aryl group having 6 to 20 carbon atoms. [ka] (In the above general formulas (w-1) to (w-3), R s represents a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, q represents 0 or 1, and * represents a bond.

[0107] As the (c) silicon-containing compound, any of the compounds of the following formulae is more preferred, and trimethylsilanol is more preferred from the viewpoint of productivity. [ka]

[0108] When the metal-containing film-forming compound contains the ligand having the ring structure (t) and (c) a ligand derived from a silicon-containing compound, the content of the ligand having the ring structure (t) in the metal-containing film-forming compound is preferably 10 mol% to 100 mol%, more preferably 20 mol% to 80 mol%, and even more preferably 25 mol% to 75 mol%, of the total ligands coordinated to the metal atom. The content of the ligand derived from the silicon-containing compound (c) is preferably 10 mol% to 90 mol%, more preferably 20 mol% to 80 mol%, and even more preferably 25 mol% to 75 mol%, of the total ligands coordinated to the metal atom. The content of the ligand other than (b) the ligand-forming compound and (c) the silicon-containing compound, for example, a ligand derived from an alkoxy group having 1 to 10 carbon atoms, is preferably 0 mol % to 90 mol %, more preferably 0 mol % to 75 mol %, of the total ligands coordinated to the metal atom.

[0109] The synthesis method for the metal-containing film-forming compound is not particularly limited. For example, a metal alkoxide, metal carboxylate, or metal acetylacetonate (acac) can be used as the (a) metal compound, and the compound can be obtained by reacting the alkoxy, carboxy, or acac metal with a ligand having the ring structure (t). The (a) metal compound may be hydrolyzed and condensed, followed by reaction with the ligand having the ring structure (t), or the (a) metal compound may be reacted with the ligand having the ring structure (t) followed by hydrolysis and condensation. If it is difficult to control the hydrolysis and condensation, the compound may be reacted with the ligand having the ring structure (t) in a non-aqueous environment. These are preferably adjusted appropriately depending on the properties required for the metal-containing film-forming compound and the metal-containing film. When the (c) silicon-containing compound and the compound having the ring structure (t) are used as ligands, it is preferable to react the (a) metal compound with the (c) silicon-containing compound, followed by reaction with the ligand having the ring structure (t).

[0110] Examples of methods for carrying out a hydrolysis condensation reaction using an (a) metal compound include a method in which the (a) metal compound is subjected to a hydrolysis condensation reaction in a solvent containing water. In this case, other compounds having hydrolyzable groups may be added as necessary. Furthermore, an acid such as acetic acid may be added as a catalyst for the hydrolysis condensation reaction. The lower limit of the amount of water used in this hydrolysis condensation reaction is preferably 0.2 times by mole, more preferably 1 time by mole, and even more preferably 3 times by mole, relative to the hydrolyzable groups of the (a) metal compound or the like. The upper limit of the amount of water is preferably 20 times by mole, more preferably 15 times by mole, and even more preferably 10 times by mole.

[0111] The solvent used in the synthesis reaction of the metal-containing film-forming compound is not particularly limited, and examples thereof include the same solvents as those exemplified as (B) organic solvents described below. Typical solvents and solvent mixtures include those containing ester, ether, or alcohol functional groups, such as a 70 / 30 volume mixture of propylene glycol monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME). Examples of other solvents that can be used include butanediol monomethyl ether, ethylene glycol monomethyl ether, butanediol monoethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, butanediol monopropyl ether, propylene glycol monopropyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, 1-butanol, 2-butanol, 2-methyl-1- Examples include propanol, 4-methyl-2-ethanol, acetone, tetrahydrofuran, toluene, hexane, ethyl acetate, cyclohexanone, methyl amyl ketone, propylene glycol dimethyl ether, diethylene glycol dimethyl ether, diamyl ether, isoamyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, t-butyl acetate, t-butyl propionate, propylene glycol mono t-butyl ether acetate, γ-butyrolactone, methyl isobutyl ketone, and cyclopentyl methyl ether.

[0112] <Metal-containing film forming composition> The present invention also provides a metal-containing film-forming composition that functions as a metal-containing film material used in semiconductor manufacturing, the metal-containing film-forming composition containing the above-described (A) metal-containing film-forming compound and (B) organic solvent.

[0113] <(B) Organic solvent> The (B) organic solvent that can be used in the metal-containing film-forming composition of the present invention is not particularly limited as long as it dissolves the above-mentioned (A) metal-containing film-forming compound, and, if contained, the later-described (C) crosslinking agent, (D) acid generator, (E) surfactant, and other additives.

[0114] Specifically, the organic solvents described in paragraphs

[0091] and

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

[0115] The amount of the organic solvent to be added is preferably 200 to 10,000 parts by mass, more preferably 250 to 5,000 parts by mass, per 100 parts by mass of the (A) compound for forming a metal-containing film.

[0116] <(B1) High-boiling point solvent> In the metal-containing film-forming composition of the present invention, the (B) organic solvent may contain (B1) a high-boiling point solvent.

[0117] That is, it is preferable that the (B) organic solvent contains at least one organic solvent having a boiling point of 180° C. or higher as the (B1) high boiling point solvent.

[0118] For example, the (B) organic solvent may be a mixture of one or more organic solvents having a boiling point of less than 180° C. and one or more organic solvents having a boiling point of 180° C. or higher ((B1) high boiling point solvents).

[0119] The (B1) high-boiling point solvent is not particularly limited as long as it can dissolve each component of the metal-containing film-forming composition of the present invention, and may be any of hydrocarbons, alcohols, ketones, esters, ethers, chlorinated solvents, etc., but specific examples include 1-octanol, 2-ethylhexanol, 1-nonanol, 1-decanol, 1-undecanol, ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4-heptanediol, 2-ethyl-1,3-Hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, glycerin, n-nonyl acetate, monohexyl ether, ethylene glycol mono-2-ethylhexyl ether, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, diethylene glycol monoethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol monoisobutyl ether, diethylene glycol monohexyl ether, diethylene glycol monophenyl ether, diethylene glycol monobenzyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol butyl methyl ether, triethylene glycol dimethyl ether, triethylene glycol monomethyl ether, triethylene glycol-n-butyl ether, triethylene glycol butyl methyl ether, tetraethylene glycol dimethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-n-butyl ether, tripropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, tripropylene glycol mono-n-propyl ether, tripropylene glycol mono-n-butyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, triacetin, propylene glycol diacetate, dipropylene glycol methyl-n-propyl ether, dipropylene glycol methyl ether acetate, 1,4-butanediol diacetate, 1,3-butylene glycol diacetate, 1,Examples of the diester include 6-hexanediol diacetate, triethylene glycol diacetate, γ-butyrolactone, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, dihexyl malonate, diethyl succinate, dipropyl succinate, dibutyl succinate, dihexyl succinate, dimethyl adipate, diethyl adipate, and dibutyl adipate, and these may be used alone or in combination.

[0120] The (B1) high-boiling-point solvent may be appropriately selected from, for example, those listed above, depending on the temperature at which the metal-containing film-forming composition of the present invention is heat-treated. The (B1) high-boiling-point solvent preferably has a boiling point of 180°C to 300°C, and more preferably 200°C to 300°C. Such a boiling point prevents excessively rapid evaporation during baking (heat treatment), thereby suppressing the occurrence of defects due to drying during film formation. Furthermore, such a boiling point prevents the solvent from remaining in the film after baking without volatilizing, thereby eliminating the risk of adversely affecting film properties such as etching resistance.

[0121] When a (B1) high-boiling point solvent is used, the blending amount is preferably 1 to 30 parts by mass per 100 parts by mass of the organic solvent having a boiling point of less than 180° C. This blending amount is preferable because it can impart sufficient thermal fluidity during baking and does not remain in the film, leading to deterioration of film properties such as etching resistance.

[0122] <Other ingredients> The composition may further contain one or more of (C) a crosslinking agent, (D) an acid generator, and (E) a surfactant.

[0123] Hereinafter, components that may be contained in the composition for forming a metal-containing film of the present invention other than the (A) compound for forming a metal-containing film and the (B) organic solvent will be described.

[0124] [(C) Crosslinking agent] A (C) crosslinking agent can also be added to the metal-containing film-forming composition of the present invention to enhance curability and further suppress intermixing with the resist upper layer film. The crosslinking agent is not particularly limited, and a wide variety of known crosslinking agents can be used. Examples include melamine-based crosslinking agents, glycoluril-based crosslinking agents, benzoguanamine-based crosslinking agents, urea-based crosslinking agents, β-hydroxyalkylamide-based crosslinking agents, isocyanurate-based crosslinking agents, aziridine-based crosslinking agents, oxazoline-based crosslinking agents, epoxy-based crosslinking agents, and phenol-based crosslinking agents. The (C) crosslinking agent can be used alone or in combination of two or more. When a crosslinking agent is added, the amount added is preferably 5 to 50 parts by mass, more preferably 10 to 40 parts by mass, per 100 parts by mass of the (A) metal-containing film-forming compound. Addition of 5 parts by mass or more ensures sufficient curability and suppresses intermixing with the resist upper layer film. On the other hand, if the amount added is 50 parts by mass or less, there is no risk of deterioration in dry etching resistance due to a decrease in the proportion of the (A) metal-containing film-forming compound in the composition.

[0125] Specific examples of the melamine-based crosslinking agent include hexamethoxymethylated melamine, hexabutoxymethylated melamine, alkoxy- and / or hydroxy-substituted products thereof, and partial self-condensates thereof.

[0126] Specific examples of glycoluril crosslinking agents include tetramethoxymethylated glycoluril, tetrabutoxymethylated glycoluril, alkoxy and / or hydroxy substituted products thereof, and partial self-condensates thereof.

[0127] Specific examples of benzoguanamine-based crosslinking agents include tetramethoxymethylated benzoguanamine, tetrabutoxymethylated benzoguanamine, alkoxy- and / or hydroxy-substituted products thereof, and partial self-condensates thereof.

[0128] Specific examples of urea-based crosslinking agents include dimethoxymethylated dimethoxyethylene urea, its alkoxy and / or hydroxy substituted derivatives, and partial self-condensates thereof.

[0129] A specific example of the β-hydroxyalkylamide crosslinking agent is N,N,N',N'-tetra(2-hydroxyethyl)adipamide.

[0130] Specific examples of the isocyanurate crosslinking agent include triglycidyl isocyanurate and triallyl isocyanurate.

[0131] Specific examples of the aziridine crosslinking agent include 4,4'-bis(ethyleneiminocarbonylamino)diphenylmethane and 2,2-bishydroxymethylbutanol-tris[3-(1-aziridinyl)propionate].

[0132] Specific examples of the oxazoline-based crosslinking agent include 2,2'-isopropylidenebis(4-benzyl-2-oxazoline), 2,2'-isopropylidenebis(4-phenyl-2-oxazoline), 2,2'-methylenebis(4,5-diphenyl-2-oxazoline), 2,2'-methylenebis(4-phenyl-2-oxazoline), 2,2'-methylenebis(4-tert-butyl-2-oxazoline), 2,2'-bis(2-oxazoline), 1,3-phenylenebis(2-oxazoline), 1,4-phenylenebis(2-oxazoline), and 2-isopropenyloxazoline copolymer.

[0133] Specific examples of epoxy-based crosslinking agents include diglycidyl ether, ethylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,4-cyclohexanedimethanol diglycidyl ether, poly(glycidyl methacrylate), trimethylolethane triglycidyl ether, trimethylolpropane triglycidyl ether, and pentaerythritol tetraglycidyl ether.

[0134] Specific examples of phenol-based crosslinking agents include compounds represented by the following general formula (10). [ka] (wherein Q is a single bond or a q 1 R is a 2-valent hydrocarbon group. 16 is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. 1 is an integer between 1 and 5.)

[0135] Q is a single bond or a q having 1 to 20 carbon atoms 1 q is a valent hydrocarbon group. 1 is an integer of 1 to 5, and more preferably 2 or 3. Specific examples of Q include methane, ethane, propane, butane, isobutane, pentane, cyclopentane, hexane, cyclohexane, methylpentane, methylcyclohexane, dimethylcyclohexane, trimethylcyclohexane, benzene, toluene, xylene, ethylbenzene, ethylisopropylbenzene, diisopropylbenzene, methylnaphthalene, ethylnaphthalene, and eicosane. 1 Examples of R include groups in which two hydrogen atoms have been removed. 16 is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. Specific examples of the alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, an isopentyl group, a hexyl group, an octyl group, an ethylhexyl group, a decyl group, and an eicosanyl group, and a hydrogen atom or a methyl group is preferred.

[0136] Specific examples of the compound represented by the general formula (10) include the following compounds: Among these, hexamethoxymethylated triphenolmethane, triphenolethane, 1,1,1-tris(4-hydroxyphenyl)ethane, and tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene are preferred from the viewpoint of improving the curability and thickness uniformity of the metal-containing film.

[0137] [ka] (In the formula, R 16 is the same as the above equation (10).

[0138] [ka] (In the formula, R 16 is the same as the above equation (10).

[0139] <(D) Acid generator> In the metal-containing film-forming composition of the present invention, an acid generator (D) can be added to further accelerate the curing reaction of the metal-containing film-forming compound (A). Acid generators include those that generate acid upon thermal decomposition and those that generate acid upon light irradiation, and either can be added. Specifically, materials described in paragraphs

[0061] to

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

[0140] The acid generators can be used alone or in combination of two or more. When an acid generator is added, the amount added is preferably 0.05 to 50 parts by mass, more preferably 0.1 to 10 parts by mass, per 100 parts by mass of the (A) compound for forming a metal-containing film.

[0141] <(E) Surfactant> To the metal-containing film-forming composition of the present invention, a surfactant (E) can be added to improve the coating properties in spin coating. Examples of the surfactant include those described in JP-A-2009-269953.

[0142] The surfactant may be added in an amount of preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, per 100 parts by mass of the (A) compound for forming a metal-containing film.

[0142] <Metal-containing film formation method> The present invention provides a method for forming a metal-containing film that functions as a resist underlayer film of a multilayer resist film used in lithography or a planarizing film for semiconductor manufacturing, using the above-mentioned metal-containing film-forming composition.

[0143] In the method for forming a metal-containing film using the metal-containing film-forming composition of the present invention, the metal-containing film-forming composition is coated onto a substrate to be processed by spin coating or the like. By using spin coating or the like, excellent embedding properties can be obtained. After spin coating, the solvent is evaporated, and baking (heat treatment) is performed to promote crosslinking reactions and prevent mixing with the resist top layer film or resist intermediate film. Baking is preferably performed at 100°C or higher and 600°C or lower for 10 to 600 seconds, more preferably 150°C or higher and 500°C or lower for 10 to 300 seconds. Considering the effects on device damage and wafer deformation, the upper limit of the heating temperature in lithography wafer processing is preferably 600°C or lower, more preferably 500°C or lower.

[0144] Furthermore, in a method for forming a metal-containing film using the metal-containing film-forming composition of the present invention, the metal-containing film can be formed by coating the metal-containing film-forming composition of the present invention onto a substrate to be processed by a spin coating method or the like, as described above, and then baking and curing the metal-containing film-forming composition in an atmosphere having an oxygen concentration of 0.1 vol.% or more and 21 vol.% or less, thereby forming a metal-containing film.

[0145] By baking the metal-containing film-forming composition of the present invention in such an oxygen atmosphere, a sufficiently cured film can be obtained. Although air can be used as the atmosphere during baking, it is preferable to seal in an inert gas such as N2, Ar, or He to reduce the oxygen content and prevent oxidation of the metal-containing film. To prevent oxidation, the oxygen concentration must be controlled, preferably to 1000 ppm or less, more preferably 100 ppm or less (volume basis). Preventing oxidation of the metal-containing film during baking is preferable because it prevents increased absorption and reduced etching resistance.

[0146] <Pattern Forming Method Using Metal-Containing Film-Forming Composition> In addition, in the present invention, a pattern formation method by a multilayer resist process using the above-mentioned metal-containing film-forming composition includes: A method for forming a pattern on a workpiece substrate, comprising: (I-1) a step of directly or indirectly applying the metal-containing film-forming composition onto a substrate to be processed, followed by heat treatment to form a metal-containing film; (I-2) forming the resist top layer film directly or indirectly on the metal-containing film using a photoresist material; (I-3) a step of pattern-exposing the resist upper layer film and then developing it with a developer to form a pattern on the resist upper layer film; (I-4) a step of transferring the pattern to the metal-containing film directly or indirectly by dry etching using the resist upper layer film on which the pattern has been formed as a mask; and (I-5) A step of directly or indirectly processing the substrate to be processed using the metal-containing film on which the pattern has been formed as a mask to form a pattern on the substrate to be processed. The present invention provides a pattern forming method comprising the steps of:

[0147] In the pattern formation method of the present invention, it is preferable that at least one organic resist underlayer film is included between the substrate to be processed and the metal-containing film, and it is preferable that a resist toplayer film is formed directly on the metal-containing film.

[0148] (3-layer resist process) For example, the present invention provides a pattern formation method using the above-mentioned metal-containing film-forming composition through a three-layer resist process, which includes forming an organic resist underlayer film on a substrate to be processed using an organic resist underlayer film material, forming a metal-containing film on the organic resist underlayer film using the metal-containing film-forming composition of the present invention, forming a resist upper layer film on the metal-containing film using a photoresist material, pattern-exposing the resist upper layer film and developing it with a developer to form a pattern in the resist upper layer film, transferring the pattern to the metal-containing film by dry etching using the resist upper layer film on which the pattern has been formed as a mask, transferring the pattern to the organic resist underlayer film by dry etching using the metal-containing film on which the pattern has been transferred as a mask, and processing the substrate to be processed using the organic resist underlayer film on which the pattern has been formed as a mask to form a pattern on the substrate to be processed.

[0149] A pattern formation method using a three-layer resist process is shown in Figure 1. First, an organic resist underlayer film 2 is formed on a substrate 1 using an organic resist underlayer film material (IA). Next, a metal-containing film 3 is formed on the organic resist underlayer film 2 using a metal-containing film-forming composition of the present invention (IB). Next, a resist upper layer film 4 is formed on the metal-containing film 3 using a photoresist material (IC). Exposure P is performed using a mask 5 (ID), and after exposing the resist upper layer film 4 and the metal-containing film 3 (IE), a resist upper layer film pattern 4a is formed on the resist upper layer film 4 (IF). Using the resulting resist upper layer film pattern 4a as a mask, the pattern is transferred to the metal-containing film 3 by dry etching (IG). After removing the resist upper layer film pattern 4a, the pattern is transferred to the organic resist underlayer film 2 by dry etching using the resulting metal-containing film pattern 3a as a mask, transferring the organic resist underlayer film pattern 2a (IH). After removing the metal-containing film pattern 3a, the substrate 1 is processed using the obtained organic resist underlayer film pattern 2a as a mask to form a pattern 1a on the substrate (II).

[0150] The resist top layer film in the three-layer resist process exhibits etching resistance to halogen-based gases such as chlorine-based gases and fluorine-based gases. Therefore, in the three-layer resist process, dry etching of the metal-containing film using the resist top layer film as a mask is preferably performed using an etching gas mainly containing a halogen-based gas.

[0151] The metal-containing film in the three-layer resist process exhibits resistance to etching by oxygen-based gases. Therefore, in the three-layer resist process, the dry etching of the organic resist underlayer film using the metal-containing film as a mask is preferably performed using an etching gas mainly containing an oxygen-based gas.

[0152] The organic resist underlayer film in the above three-layer resist process exhibits etching resistance against fluorine-based gases, and therefore, in the above three-layer resist process, dry etching of the substrate to be processed using the organic resist underlayer film as a mask is preferably performed using an etching gas mainly containing a fluorine-based gas.

[0153] Examples of organic resist underlayer film materials that can be used for the organic resist underlayer film include those already known as underlayer films for three-layer resist methods or two-layer resist methods using a silicon resist composition, the 4,4'-(9-fluorenylidene)bisphenol novolac resin (molecular weight 11,000) described in JP 2005-128509 A, and many other resins, including novolac resins, that are known as resist underlayer film materials for two-layer and three-layer resist methods. Furthermore, if higher heat resistance than that of ordinary novolacs is desired, a polycyclic skeleton such as 6,6'-(9-fluorenylidene)-di(2-naphthol) novolac resin can be incorporated, and polyimide-based resins can also be selected (for example, JP 2004-153125 A).

[0154] The organic resist underlayer film can be formed on a substrate to be processed by spin coating or the like using a composition solution, similar to the photoresist composition. After forming the organic underlayer film by spin coating or the like, it is desirable to bake it to evaporate the organic solvent. The baking temperature is preferably in the range of 80 to 400°C, and the baking time is preferably in the range of 10 to 300 seconds.

[0155] Instead of the organic resist underlayer film, an organic hard mask formed by a CVD method or an ALD method can also be used.

[0156] In the pattern formation method, the resist top layer film may be either positive or negative, and the same photoresist composition as commonly used may be used. When the resist top layer film is formed from the photoresist composition, it may be formed by a spin coating method or a deposition process using CVD or ALD.

[0157] When forming a photoresist composition by spin coating, the resist is prebaked after application, preferably at 60 to 180°C for 10 to 300 seconds. Then, exposure is performed according to a conventional method, followed by post-exposure baking (PEB) and development to obtain a resist pattern. The thickness of the resist top layer film is not particularly limited, but is preferably 10 to 500 nm, and more preferably 20 to 400 nm.

[0158] Examples of exposure light include high energy rays with a wavelength of 300 nm or less, specifically excimer lasers with wavelengths of 248 nm, 193 nm, and 157 nm, soft X-rays with wavelengths of 3 to 20 nm, electron beams, and X-rays.

[0159] The resist upper layer film can be patterned by photolithography with a wavelength of 5 nm or more and 300 nm or less, direct writing with an electron beam, nanoimprinting, or a combination thereof, but EUV light is most preferred in the present invention.

[0160] In the pattern forming method, the development method is preferably alkaline development or development using an organic solvent.

[0161] Next, etching is performed using the obtained resist pattern as a mask. In the three-layer resist process, etching of the metal-containing film is performed using a chlorine-based or fluorocarbon-based gas, with the upper resist pattern as a mask. This results in the formation of a metal-containing film pattern.

[0162] Next, the organic resist underlayer film is etched using the resulting metal-containing film pattern as a mask, preferably using an etching gas mainly containing an oxygen-based gas.

[0163] The metal-containing film obtained using the metal-containing film-forming composition of the present invention is characterized by excellent etching resistance when etching these organic resist underlayer films.

[0164] The next etching of the workpiece can also be carried out by a conventional method. For example, if the workpiece is made of SiO2, SiN, or a silica-based low dielectric constant insulating film, etching is carried out using mainly fluorocarbon gases.

[0165] The workpiece (substrate) is not particularly limited, and may be a substrate such as Si, α-Si, p-Si, SiO2, SiN, SiON, W, TiN, or Al, or a substrate with a workpiece layer formed thereon. The workpiece layer may be a low-k film or a stopper film thereof, such as Si, SiO2, SiON, SiN, p-Si, α-Si, W, W-Si, Al, Cu, or Al-Si, and may be formed to a thickness of typically 50 to 10,000 nm, particularly 100 to 5,000 nm. When forming a workpiece layer, the substrate and workpiece layer are made of different materials.

[0166] (two-layer resist process) Furthermore, the present invention can provide a pattern formation method by a two-layer resist process using the above-mentioned metal-containing film-forming composition, which includes forming a metal-containing film on a workpiece substrate using the metal-containing film-forming composition, forming a resist upper layer film on the metal-containing film using a photoresist material, exposing the resist upper layer film to light and developing it with a developer to form a pattern in the resist upper layer film, transferring the pattern to the metal-containing film by dry etching using the resist upper layer film on which the pattern has been formed as a mask, and processing the workpiece substrate by dry etching using the metal-containing film on which the pattern has been transferred as a mask to form a pattern on the workpiece substrate.

[0167] The metal-containing film obtained using the metal-containing film-forming composition of the present invention is characterized by excellent etching resistance during etching of the substrate to be processed. Therefore, in the above-mentioned two-layer resist process, the dry etching of the substrate to be processed using the metal-containing film as a mask is preferably performed using an etching gas mainly containing a fluorine-based gas.

[0168] (Metal-containing film peeling process) Furthermore, in the pattern formation method of the present invention, it is preferable that after the step of processing a film directly below the metal-containing film (hereinafter referred to as the processed film; for example, this refers to an organic resist underlayer film in the case of the three-layer resist process, or to the processed substrate in the case of the two-layer resist process) to form a pattern in the processed film, the metal-containing film remaining on the processed film pattern is removed with a chemical solution. When this step is performed after the processed film etching step, the metal-containing film remaining on the upper side of the substrate is removed. Furthermore, this step can also be performed on a patterned or unpatterned metal-containing film before the substrate etching step.

[0169] The wet stripping method is shown in Figure 2. In a workpiece having an organic resist underlayer film 2, a metal-containing film 3, and a resist toplayer film 4 formed on a workpiece substrate 1, first, mask exposure is performed on the resist toplayer film 4. Development and rinsing are then performed to form a resist toplayer film pattern 4a. The resulting resist toplayer film pattern 4a is then used as a mask to transfer the pattern to the metal-containing film 3 by dry etching, thereby obtaining a metal-containing film pattern 3a. The resist toplayer film pattern 4a is then removed, and the resulting metal-containing film pattern 3a is used as a mask to transfer the pattern to the organic resist underlayer film 2 by dry etching, thereby obtaining an organic resist underlayer film pattern 2a. The metal-containing film pattern 3a is then removed by wet stripping.

[0170] The metal-containing film of the present invention can be removed by wet processing using a chemical solution, and therefore, a pattern can be formed without damaging the substrate to be processed.

[0171] Examples of methods for removing the metal-containing film include a method of dry etching the metal-containing film and a method of bringing the metal-containing film into contact with a liquid such as a basic liquid or an acidic liquid.

[0172] The acid-containing removal liquid is not particularly limited as long as it is an acidic solution containing an acid, but from the viewpoint of further improving the removability of the metal-containing film, a liquid containing hydrogen peroxide and an acid is preferable, and more specifically, an aqueous solution containing hydrochloric acid and hydrogen peroxide (SC-2 chemical solution), an aqueous solution containing sulfuric acid and hydrogen peroxide (SPM chemical solution), or an aqueous solution containing hydrofluoric acid and hydrogen peroxide (FPM chemical solution) is particularly preferable.

[0173] The base-containing removal solution is not particularly limited as long as it is a basic solution containing a base. Examples of bases include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, dimethylethanolamine, triethanolamine, tetramethylammonium hydroxide (hereinafter also referred to as "TMAH"), tetraethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo[5.4.0]-7-undecene, and 1,5-diazabicyclo[4.3.0]-5-nonene. Among these, ammonia is preferred from the viewpoint of avoiding damage to the substrate.

[0174] As the base-containing removal liquid, from the viewpoint of further improving the removability of the metal-containing film, a liquid containing a base and water, or a liquid containing a base, hydrogen peroxide solution, and water is preferred, and more specifically, a mixed aqueous solution of ammonia and hydrogen peroxide (such as a mixed aqueous solution of 25% ammonia solution / 30% hydrogen peroxide solution / water=1 / 2 / 40 or a mixed aqueous solution of 25% ammonia solution / 30% hydrogen peroxide solution / water=1 / 1 / 5 (SC1)) is particularly preferred.

[0175] The wet stripping method is not particularly limited as long as it allows the metal-containing film and the stripping solution to come into contact with each other for a certain period of time under heated conditions, and examples thereof include a method of immersing a substrate having a metal-containing film in heated alkaline hydrogen peroxide solution, a method of spraying alkaline hydrogen peroxide solution in a heated environment, a method of coating heated alkaline hydrogen peroxide solution, etc. After each of these methods, the substrate may be washed with water and dried.

[0176] When the metal-containing film removal step is performed using a stripping solution, the lower limit of the temperature is preferably 23° C., more preferably 40° C., and more preferably 50° C. The upper limit of the temperature is preferably 100° C., and more preferably 90° C.

[0177] In the immersion method, the lower limit of the immersion time is preferably 1 second, more preferably 10 seconds, even more preferably 20 seconds, and particularly preferably 30 seconds. From the viewpoint of suppressing the influence on the substrate, the upper limit of the immersion time is preferably 60 minutes, more preferably 30 minutes, even more preferably 20 minutes, and particularly preferably 10 minutes. [Example]

[0178] The present invention will be explained in more detail below by showing synthesis examples, examples, and comparative examples, but the present invention is not limited to these.

[0179] [Synthesis example] In the following synthesis examples, the following organic group raw material group G: (G1) to (G12) and silicon-containing organic group raw material group H: (H1) to (H2) were used.

[0180] The organic group raw materials G: (G1) to (G12) are shown below. [ka]

[0181] The silicon-containing organic group raw materials H: (H1) to (H2) are shown below. [ka]

[0182] As the metal source M, the following metal compounds were used. (M1): Titanium tetraisopropoxide (Sigma-Aldrich Corp, 377996) (M2): Zr(OBu)4: Zirconium(IV) tetrabutoxide (80% by mass solution in 1-butanol) (Tokyo Chemical Industry Co., Ltd., Z0016) (M3): Hf(OBu)4: Hafnium(IV) n-butoxide (Sigma-Aldrich Corp, 667943)

[0183] [Synthesis Example 1] Synthesis of metal-containing film-forming compound (A-1) Under a nitrogen atmosphere, 7.10 g of titanium tetraisopropoxide (M1) was dissolved in 15.0 g of PGMEA / PGME (weight ratio 70 / 30) solution, and the reaction temperature was increased to 60 ° C. with stirring. A mixture of 2.90 g of compound G1 suspended in 5.50 g of PGMEA / PGME (weight ratio 70 / 30) solution was added to the reaction system, and stirring was continued for 1 hour while maintaining the reaction temperature at 60 ° C. After cooling to room temperature, the resulting reaction solution was filtered through a 0.45 μm PTFE filter to obtain a PGMEA / PGME solution of the metal-containing film-forming compound (A-1).

[0184] [Synthesis Examples 2 to 12] Synthesis of metal-containing film-forming compounds (A-2) to (A-9) and (R-1) to (R-3) The metal-containing film-forming compounds (A-2) to (A-9) and (R-1) to (R-3) shown in Table 1 were obtained under the same reaction conditions as in [Synthesis Example 1], except that the metal source M and the organic group raw material group G were used in the amounts shown in Table 1. Table 1 also shows (A-1). [Table 1]

[0185] [Synthesis Example 13] Synthesis of metal-containing film-forming compound (A-10) Under a nitrogen atmosphere, 7.10 g of titanium tetraisopropoxide (M1) was dissolved in 15.00 g of a PGMEA / PGME (70 / 30 weight ratio) solution. The reaction temperature was increased to 50°C while stirring, and 6.76 g of compound H1 was added dropwise to the solution. After the dropwise addition, the reaction temperature was increased to 60°C and stirring was continued for 2 hours. Next, a mixture obtained by suspending 4.50 g of compound G4 in 5.50 g of a PGMEA / PGME (70 / 30 weight ratio) solution was added to the reaction system, and stirring was continued for 1 hour while maintaining the reaction temperature at 60°C. After cooling to room temperature, the resulting reaction solution was filtered through a 0.45 μm PTFE filter to obtain a PGMEA / PGME solution of the metal-containing film-forming compound (A-10).

[0186] [Synthesis Example 14] Synthesis of metal-containing film-forming compound (A-11) Compound (A-11) shown in Table 2 was obtained under the same reaction conditions as in Synthesis Example 13, except that the metal source M, organic group raw material group G, and silicon-containing organic group raw material group H were used in the amounts shown in Table 2. Compound (A-10) is also shown. [Table 2]

[0187] [Synthesis Example 15] Synthesis of metal-containing film-forming compound (A-12) Under a nitrogen atmosphere, 35.53 g of titanium tetraisopropoxide (M1) was dissolved in 50.00 g of 2-propanol. A solution of 1.69 g of deionized water and 70.0 g of 2-propanol was added dropwise to the resulting solution over 2 hours at room temperature while stirring. 22.52 g of compound G4 was added to the resulting solution and stirred at room temperature for 30 minutes. The solution was concentrated under reduced pressure at 30°C and then heated to 60°C and continued to be heated under reduced pressure until no more distillate was produced. When no more distillate was observed, 100.50 g of a PGMEA / PGME (70 / 30 weight ratio) solution was added and heated at 40°C under reduced pressure until no more IPA was produced, yielding a PGMEA / PGME solution of the metal-containing film-forming compound (A-12).

[0188] [Synthesis Example 16] Synthesis of metal-containing film-forming compound (A-13) Compound (A-13) shown in Table 3 was obtained under the same reaction conditions as in Synthesis Example 15, except that the metal source M and the organic group raw material group G were used in the amounts shown in Table 3. Compound (A-12) is also shown. [Table 3]

[0189] Preparation of metal-containing film-forming compositions (UDL-1 to 16, comparative UDL-1 to 3) The metal-containing film-forming compositions were prepared using the above-mentioned metal-containing film-forming compounds (A-1) to (A-13), acid generator (D-1), crosslinkers (XL-1) to (XL-2), and high-boiling-point solvent (B1) (F1: ethylene glycol dibenzyl ether, boiling point 364°C). The compositions were dissolved in organic solvents in the proportions shown in Table 4, and then filtered through a 0.1 μm fluororesin filter to prepare the metal-containing film-forming compositions (UDL-1 to 16, Comparative Examples UDL-1 to 3). [ka]

[0190] [Table 4]

[0191] [Etching Resistance Evaluation (Examples 1-1 to 1-16, Comparative Examples 1-1 to 1-5)] The metal-containing film-forming compositions (UDL-1 to 16 and comparative examples UDL-1 to 3) were applied to silicon substrates and heated at 250°C for 60 seconds using a hot plate to form metal-containing films with a thickness of 30 nm (film thickness a). In Comparative Example 1-4, the following silicon atom-containing resist intermediate film material (SOG-1) was applied and baked at 220° C. for 60 seconds to form a resist intermediate film having a thickness of 30 nm (film thickness a). The silicon-containing resist interlayer material (SOG-1) was prepared by dissolving a polymer designated as ArF silicon-containing interlayer polymer (SiP1) and a thermal crosslinking catalyst (CAT1) in a solvent containing 0.1 mass% of FC-4430 (manufactured by Sumitomo 3M) in the proportions shown in Table 5, and filtering the solution through a fluororesin filter with a pore size of 0.1 μm.

[0192] [Table 5]

[0193] The structural formulae of the ArF silicon-containing intermediate film polymer (SiP1) and thermal crosslinking catalyst (CAT1) used are shown below. [ka]

[0194] In Comparative Example 1-5, the following organic resist underlayer film material (SOC-1) was applied and baked at 350° C. for 60 seconds to form a resist underlayer film with a film thickness of 50 nm (film thickness a). The organic resist underlayer film material (SOC-1) was prepared by dissolving the polymer indicated as organic underlayer film polymer (CP1) in a solvent containing 0.1 mass % of FC-4430 (manufactured by Sumitomo 3M Limited) in the proportions shown in Table 6, and filtering the resultant solution through a fluororesin filter having a pore size of 0.1 μm.

[0195] [Table 6]

[0196] The structural formula of the organic underlayer polymer (CP1) used is shown below. [ka] Mw=7,000, Mw / Mn=3.50

[0197] Next, etching was performed using CF4 gas and O2 gas under the following conditions using a ULVAC etching system CE-300I, and the film thickness b was measured. The film thickness etched per minute using each gas was calculated as the etching rate (nm / min) from the film thickness etched over a specified time (film thickness a - film thickness b). The etching rate for CF4 gas was judged as "A (very good)" when it was less than 20 nm / min, "B (good)" when it was 20 nm / min or more but less than 30 nm / min, and "C (poor)" when it was 30 nm / min or more. The etching rate for O2 gas was judged as "A (very good)" when it was less than 20 nm / min, "B (good)" when it was 20 nm / min or more but less than 30 nm / min, and "C (poor)" when it was 30 nm / min or more. The results are shown in Table 7.

[0198] Dry etching conditions with CF4 gas Pressure: 3Pa Antenna RF power: 100W Bias RF power: 15W CF4 gas flow rate: 15sccm Time: 30sec

[0199] Dry etching conditions with O2 gas Pressure: 3Pa Antenna RF power: 300W Bias RF power: 10W O2 gas flow rate: 25sccm Time: 30sec

[0200] [Table 7]

[0201] As shown in Table 7, it was found that all of the metal-containing film-forming compositions of the present invention (UDL-1 to 16) exhibited excellent etching resistance to CF4 gas and O2 gas. The results of the examples show that the SOG-1 used in Comparative Examples 1-4 has superior resistance to etching using CF4 gas, and therefore it can be said that the SOG-1 is suitable for a three-layer resist process in which a resist pattern is transferred to a substrate to be processed in combination with an organic resist underlayer film. The results of the examples show that the etching resistance to O2 gas is superior to that of SOC-1 used in Comparative Examples 1-5, and therefore it can be said that the examples are suitable for a two-layer resist process in which a resist pattern is transferred to a substrate to be processed in combination with a photoresist top layer film.

[0202] [Coated Film Wet Etching Test (Examples 2-1 to 2-16, Comparative Examples 2-1 to 2-4)] The metal-containing film-forming compositions (UDL-1 to 16 and comparative examples UDL-1 to 3) were applied to silicon substrates and heated at 250°C for 60 seconds using a hot plate to form 30-nm-thick metal-containing films. These metal-containing films were then immersed in a basic solution (a 1:1:5 mixture of 25% aqueous ammonia, 30% aqueous hydrogen peroxide, and water) at 65°C for 2 minutes. The remaining film thickness was measured using a JA Woollam M-2000 high-speed spectroscopic ellipsometer to evaluate whether or not the film thickness changed before and after immersion in the basic solution. Films with a change in film thickness of 70% or more were rated "good," and films with a change in film thickness of less than 70% were rated "poor." The results are shown in Table 8.

[0203] [Table 8]

[0204] As shown in Table 8, the metal-containing film-forming compositions (UDL-1 to 16) of the present invention exhibited better strippability using a basic solution than the metal-containing films formed using comparative examples UDL-1 to 3, which do not contain a ligand having the specific ring structure (t), and the silicon-containing film formed from SOG-1. It is believed that the inclusion of a ligand having the specific ring structure (t) improves the penetration of the stripping solution. Comparative UDL-2 uses R-2, which contains a ligand derived from G11. However, although G11 contains the ring structure (t), the ligand derived from it is ring-opened and does not contain the ring structure (t).

[0205] [Patterning Test (Examples 3-1 to 3-16, Comparative Examples 3-1 to 3-4)] An organic resist underlayer film was spin-coated onto a silicon wafer with a 100 nm SiO2 film using an SOC film (ODL-306, carbon content 61 atomic%) manufactured by Shin-Etsu Chemical Co., Ltd., and baked at 350°C for 60 seconds to produce a 50 nm thick carbon film. Next, the above metal-containing film-forming compositions (UDL-1 to 16 and comparative examples UDL-1 to 3) and SOG-1 were coated onto the organic resist underlayer film, and heated at 250°C or 220°C for 60 seconds using a hot plate to form a 30 nm thick resist intermediate film.

[0206] Next, the resist material shown in Table 9 was spin-coated onto the metal-containing film and pre-baked on a hot plate at 105°C for 60 seconds to produce a 40 nm thick resist film. This was then exposed using an ASML EUV scanner NXE3300 (NA 0.33, σ 0.9 / 0.6, dipole illumination, L / S pattern with a 36 nm pitch on the wafer), subjected to PEB on a hot plate at 100°C for 60 seconds, and developed for 30 seconds in a 2.38 mass% TMAH aqueous solution to obtain a pattern with a line dimension of 22 nm. The line dimensions were measured using a length-measuring SEM (CG5000) manufactured by Hitachi High-Technologies Corporation, and pattern collapse was observed. Pattern collapse was evaluated as "good" when no pattern collapse was observed, and as "poor" when pattern collapse was observed. The cross-sectional shape was observed using an electron microscope (S-4800) manufactured by Hitachi High-Technologies Corporation, and the results were evaluated as "good" when no footing was observed, and as "poor" when a clear footing was observed. In addition, the exposure dose required to obtain a line dimension of 18 nm was evaluated as the sensitivity, and it was determined that a lower exposure dose contributed to higher sensitivity of the resist top layer film. The results are shown in Table 10.

[0207] [ka] [ka] Surfactant: 3M FC-4430

[0208] [Table 9] Organic solvent: PGMEA (propylene glycol monomethyl ether acetate) CyHO (cyclohexanone) PGME (Propylene Glycol Monomethyl Ether)

[0209] [Table 10]

[0210] As shown in Table 10, the metal-containing film-forming compositions of the present invention (UDL-1 to 16) were able to obtain vertically shaped pattern cross sections in the formation of a 22 nm line width pattern using EUV exposure, and no pattern collapse was observed. It is believed that the metal-containing film-forming compounds of the present invention contain a ligand having a specific ring structure (t), which improves adhesion to the resist pattern. It is also believed that the developer permeability was improved, resulting in a highly rectangular resist pattern after development. Furthermore, it was found that when a metal-containing film obtained from the metal-containing film-forming composition of the present invention is used as a resist underlayer film, a resist pattern can be formed with high sensitivity. On the other hand, it was found that the metal-containing films formed using compounds for forming metal-containing films different from those of the present invention (Comparative Examples 3-1 to 3-3) were less effective in suppressing collapse of fine line patterns than the metal-containing films obtained from the metal-containing film-forming compositions of the present invention (Examples 3-1 to 3-16).In Comparative Example 3-4 using SOG-1, no pattern collapse was observed, but the cross-sectional shape of the resist showed a footing shape.

[0211] As described above, the metal-containing film-forming composition containing the metal-containing film-forming compound of the present invention has excellent adhesion to the upper layer resist, and therefore is highly effective in suppressing the collapse of fine line patterns.Furthermore, it can form a metal-containing film that can contribute to improving the sensitivity of the upper layer resist, and can also be easily removed, making it highly useful in the field of EUV lithography.

[0212] The present specification includes the following aspects. [1] A metal-containing film-forming compound, the metal-containing film-forming compound contains at least one metal atom selected from the group consisting of Ti, Zr, and Hf, and a ligand coordinated to the metal atom via an oxygen atom; The ligand is a ring having 4 or more carbon atoms and containing one or more oxygen atoms; a ring having 3 or more carbon atoms and containing 2 or more oxygen atoms, and A ring with 3 or more carbon atoms containing one or more oxygen atoms and one or more heteroatoms different from oxygen atoms A compound for forming a metal-containing film, characterized by having a ring structure (t) selected from the following: [2] The compound for forming a metal-containing film according to [1], wherein the ring structure (t) is a structure containing a ring having 4 or more carbon atoms and containing two or more oxygen atoms, or a structure containing a ring having 4 or more carbon atoms and one or more oxygen atoms and one or more heteroatoms different from oxygen atoms. [3] The compound for forming a metal-containing film according to [1] or [2], characterized in that the ring structure (t) is bonded to one or more of a cyclic hydrocarbon having 4 to 6 carbon atoms and optionally containing a heteroatom, a cyclic hydrocarbon having 5 to 6 carbon atoms and optionally containing a heteroatom having one or more carbon-carbon double bonds, an aromatic ring, or an aromatic heterocycle to form a polycyclic structure. [4] The compound for forming a metal-containing film according to any one of [1] to [3], wherein the ring structure (t) is derived from an organic acid containing the ring structure (t). [5] The compound for forming a metal-containing film according to [4], wherein the organic acid is a carboxylic acid. [6] The compound for forming a metal-containing film according to any one of [1] to [5], wherein the ligand is derived from the following structure: [ka] (In the above formula, Ra is a monovalent organic group containing the ring structure (t), X is a group selected from a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, a substituted or unsubstituted branched alkylene group having 3 to 10 carbon atoms, a substituted or unsubstituted alkylene group having 2 to 10 carbon atoms and containing a carbon-carbon double bond, and a substituted or unsubstituted branched alkylene group having 3 to 10 carbon atoms and containing a carbon-carbon double bond, and n is 0 or 1.) [7] The compound for forming a metal-containing film according to any one of [1] to [6], further comprising a ligand derived from a silicon compound represented by the following general formula (w): [ka] (In the formula, R A , R B and R C is any organic group selected from an organic group having 2 to 30 carbon atoms and a crosslinking group having any of the structures represented by the following general formulas (w-1) to (w-3), a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, and an aryl group having 6 to 20 carbon atoms. [ka] (In the above general formulas (w-1) to (w-3), R s represents a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, q represents 0 or 1, and * represents a bond. [8] The compound for forming a metal-containing film according to any one of [1] to [7], characterized in that the compound for forming a metal-containing film is a reaction product of a metal-containing compound containing a metal compound represented by the following formula (a) or any of a hydrolysate, a condensate, and a hydrolysis condensate of a metal compound represented by the following formula (a) and a compound having the ring structure (t): [ka] (wherein M is any one of Ti, Zr, and Hf; L is a monodentate or polydentate ligand having 1 to 30 carbon atoms; X is a halogen atom, an alkoxy group, a carboxylate group, an acyloxy group, or —NR 1R 2 R is a hydrolyzable group selected from 1 and R 2 are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms; a+b=2 to 4, and a and b are integers of 0 to 4. [9] The compound for forming a metal-containing film according to [8], wherein the formula (a) is a structure of the following formula (a-1): [ka] (Wherein, M is any one of Ti, Zr, and Hf; R 1A is a monovalent organic group having 1 to 20 carbon atoms.

[10] A composition for forming a metal-containing film, which functions as a metal-containing film material used in semiconductor manufacturing, characterized by containing (A) the compound for forming a metal-containing film according to any one of [1] to [9] and (B) an organic solvent.

[11] The metal-containing film-forming composition according to

[10] , further comprising one or more of (C) a crosslinking agent, (D) an acid generator, and (E) a surfactant.

[12] The metal-containing film-forming composition according to

[10] or

[11] , wherein the (B) organic solvent contains one or more organic solvents having a boiling point of 180°C or higher as the (B1) high-boiling-point solvent.

[13] A method for forming a pattern on a workpiece substrate, comprising: (I-1) A step of directly or indirectly applying the metal-containing film-forming composition according to any one of

[10] to

[12] onto a substrate to be processed, followed by heat treatment to form a metal-containing film; (I-2) forming a resist top layer film directly or indirectly on the metal-containing film using a photoresist material; (I-3) a step of pattern-exposing the resist upper layer film and then developing it with a developer to form a pattern on the resist upper layer film; (I-4) a step of transferring the pattern to the metal-containing film directly or indirectly by dry etching using the resist upper layer film on which the pattern has been formed as a mask; and (I-5) A step of directly or indirectly processing the substrate to be processed using the metal-containing film on which the pattern has been formed as a mask to form a pattern on the substrate to be processed. A pattern forming method comprising the steps of:

[14] The pattern forming method according to

[13] , further comprising at least one organic resist underlayer film between the substrate to be processed and the metal-containing film.

[15] The pattern forming method according to

[13] or

[14] , wherein a resist upper layer film is formed directly on the metal-containing film.

[16] The pattern formation method according to any one of

[13] to

[15] , further comprising the step of removing the metal-containing film with a chemical solution after the step of forming a pattern by processing a film directly below the metal-containing film using the metal-containing film as a mask.

[17] The pattern formation method according to

[16] , wherein the chemical solution is a solution containing hydrogen peroxide and an acid, or a solution containing a base, hydrogen peroxide, and water.

[0213] The present invention is not limited to the above-described embodiments, which are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that provides similar effects is included within the technical scope of the present invention. [Explanation of symbols]

[0214] 1... substrate to be processed, 1a... pattern (pattern to be formed on the substrate to be processed), 2...organic resist underlayer film, 2a...organic resist underlayer film pattern, 3...metal-containing film, 3a...metal-containing film pattern, 4...resist upper layer film, 4a...resist upper layer film pattern, 5...mask, P...exposure.

Claims

1. A metal-containing film-forming compound, the metal-containing film-forming compound contains at least one metal atom selected from the group consisting of Ti, Zr, and Hf, and a ligand coordinated to the metal atom via an oxygen atom; The ligand is a ring having 4 or more carbon atoms and containing one or more oxygen atoms; a ring having 3 or more carbon atoms and containing two or more oxygen atoms, and A ring having 3 or more carbon atoms containing one or more oxygen atoms and one or more heteroatoms different from oxygen atoms. A compound for forming a metal-containing film, characterized in that it has a ring structure (t) selected from the following:

2. 2. The compound for forming a metal-containing film according to claim 1, wherein the ring structure (t) is a structure including a ring having 4 or more carbon atoms and containing two or more oxygen atoms, or a ring having 4 or more carbon atoms and containing one or more oxygen atoms and one or more heteroatoms other than oxygen atoms.

3. 2. The metal-containing film-forming compound according to claim 1, wherein the ring structure (t) is bonded to one or more of a cyclic hydrocarbon having 4 to 6 carbon atoms and optionally containing a heteroatom, a cyclic hydrocarbon having 5 to 6 carbon atoms and optionally containing a heteroatom having one or more carbon-carbon double bonds, an aromatic ring, or an aromatic heterocycle to form a polycyclic structure.

4. 2. The compound for forming a metal-containing film according to claim 1, wherein the ring structure (t) is derived from an organic acid containing the ring structure (t).

5. 5. The compound for forming a metal-containing film according to claim 4, wherein the organic acid is a carboxylic acid.

6. 2. The compound for forming a metal-containing film according to claim 1, wherein the ligand is derived from the following structure: 【Chemistry 1】 (In the above formula, Ra is a monovalent organic group containing the ring structure (t), X is a group selected from a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, a substituted or unsubstituted branched alkylene group having 3 to 10 carbon atoms, a substituted or unsubstituted alkylene group having 2 to 10 carbon atoms and containing a carbon-carbon double bond, and a substituted or unsubstituted branched alkylene group having 3 to 10 carbon atoms and containing a carbon-carbon double bond, and n is 0 or 1.)

7. The compound for forming a metal-containing film according to claim 1, further comprising a ligand derived from a silicon compound represented by the following general formula (w): 【Chemistry 2】 (In the formula, R Ａ , R Ｂ and R Ｃ is any organic group selected from an organic group having 2 to 30 carbon atoms and a crosslinking group having any of the structures represented by the following general formulas (w-1) to (w-3), a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, and an aryl group having 6 to 20 carbon atoms. 【Transformation 3】 (In the above general formulas (w-1) to (w-3), R ｓ represents a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, q represents 0 or 1, and * represents a bond.

8. 2. The compound for forming a metal-containing film according to claim 1, wherein the compound for forming a metal-containing film is a reaction product of a metal compound represented by the following formula (a), or a metal-containing compound containing any one of a hydrolysate, a condensate, and a hydrolysis condensate of the metal compound represented by the following formula (a), and a compound having the ring structure (t): 【Chemistry 4】 (wherein M is any one of Ti, Zr, and Hf; L is a monodentate or polydentate ligand having 1 to 30 carbon atoms; X is a halogen atom, an alkoxy group, a carboxylate group, an acyloxy group, or —NR １ R ２ R is a hydrolyzable group selected from １ and R ２ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms; a+b=2 to 4, and a and b are integers of 0 to 4.

9. 9. The compound for forming a metal-containing film according to claim 8, wherein the formula (a) has a structure represented by the following formula (a-1): 【Transformation 5】 (wherein M is any one of Ti, Zr, and Hf; R １Ａ is a monovalent organic group having 1 to 20 carbon atoms.

10. 10. A metal-containing film-forming composition that functions as a metal-containing film material used in semiconductor manufacturing, the metal-containing film-forming composition comprising (A) the metal-containing film-forming compound according to claim 1 and (B) an organic solvent.

11. 11. The metal-containing film-forming composition according to claim 10, further comprising one or more of (C) a crosslinking agent, (D) an acid generator, and (E) a surfactant.

12. 11. The metal-containing film-forming composition according to claim 10, wherein the (B) organic solvent contains, as the (B1) high-boiling-point solvent, one or more organic solvents having a boiling point of 180° C. or higher.

13. A method for forming a pattern on a workpiece substrate, comprising: (I-1) A step of forming a metal-containing film by directly or indirectly applying the metal-containing film-forming composition according to claim 10 onto a substrate to be processed, and then performing a heat treatment; (I-2) forming a resist top layer film directly or indirectly on the metal-containing film using a photoresist material; (I-3) a step of pattern-exposing the resist upper layer film and then developing it with a developer to form a pattern on the resist upper layer film; (I-4) a step of transferring the pattern to the metal-containing film directly or indirectly by dry etching using the resist upper layer film on which the pattern has been formed as a mask; and (I-5) A step of directly or indirectly processing the substrate to be processed using the metal-containing film on which the pattern has been formed as a mask to form a pattern on the substrate to be processed. A pattern forming method comprising the steps of:

14. 14. The pattern forming method according to claim 13, further comprising at least one organic resist underlayer film between the substrate to be processed and the metal-containing film.

15. The pattern forming method according to claim 13, wherein a resist upper layer film is formed directly on the metal-containing film.

16. 14. The pattern formation method according to claim 13, further comprising the step of removing the metal-containing film with a chemical solution after the step of forming a pattern by processing a film directly below the metal-containing film using the metal-containing film as a mask.

17. 17. The pattern formation method according to claim 16, wherein the chemical solution is a solution containing hydrogen peroxide and an acid, or a solution containing a base, hydrogen peroxide, and water.

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