Pattern Formation Method

Abstract

A patterning method that shows good results is provided. [Solution] This pattern formation method includes a step of forming a resist layer by applying a metal-containing resist composition onto a substrate; a removal step of applying an edge bead removal composition to the resist layer along the outer periphery of the substrate and performing an edge bead removal process; a first heat treatment step of drying and heating the resist layer that has been subjected to the removal process in the removal step; and a resist pattern formation step of performing an exposure process and a development process on the resist layer that has been subjected to the drying and heating processes in the first heat treatment step to form a resist pattern, wherein after the first heat treatment step and before the resist pattern formation step, the maximum height of humps in the resist layer in a region from 1 mm to 30 mm from the outer periphery edge toward the center of the substrate is 300 nm or less.

Description

[Technical Field]

[0001] The present invention relates to a pattern forming method including a step of applying an edge bead removal composition and performing an edge bead removal treatment. [Background technology]

[0002] In recent years, the semiconductor industry has experienced a continuous reduction in critical dimensions, which has led to the need for new types of high performance resist materials and patterning methods to meet the demands of processing and patterning smaller and smaller features.

[0003] Furthermore, with the recent rapid development of the semiconductor industry, semiconductor devices are required to have higher operating speeds and larger memory capacities, and technologies to improve the integration, reliability, and response speed of semiconductor devices are also being developed to meet these demands. In particular, it is important to precisely control / inject impurities into active regions of a silicon substrate and interconnect these regions to form elements and ultra-high density direct circuits, which is made possible by the photolithography process. That is, it is becoming increasingly important to consider integration in the photolithography process, which involves coating a resist on a substrate, selectively exposing it to ultraviolet (including extreme ultraviolet), electron beams, or X-rays, and then developing it.

[0004] In particular, in the process of forming a resist layer, the resist is coated onto the substrate while the silicon substrate is rotated, and during this process, the resist is also coated on the edge and backside of the substrate. This can cause indenter induction and pattern defects in subsequent semiconductor processes such as etching and ion implantation. Therefore, a process called EBR (Edge Bead Removal) is performed to strip and remove the resist coated on the edge and backside of the silicon substrate using a thinner composition, etc.

[0005] The EBR process uses a composition that exhibits excellent solubility in resist, effectively removes beads and resist remaining on the substrate, and does not leave any resist residue. Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a pattern forming method that reduces the defect rate when forming a fine pattern. [Means for solving the problem]

[0007] A pattern forming method according to one aspect of the present invention includes the steps of: 1. A step of applying a metal-containing resist composition onto a substrate to form a resist layer; a removing step of applying an edge bead removing composition to the resist layer along the outer periphery of the substrate to remove the edge bead; a first heat treatment step of drying and heating the resist layer that has been subjected to the removal treatment in the removal step; and a resist pattern forming step of performing an exposure process and a development process on the resist layer that has been subjected to the drying process and the heating process in the first heat treatment step to form a resist pattern; After the first heat treatment step and before the resist pattern forming step, the maximum height of a hump in the resist layer in a region from 1 mm to 30 mm from the outer circumferential edge toward the center of the substrate is 300 nm or less.

[0008] 2. In the pattern formation method described in 1 above, the maximum height of the hump may be 10 nm or more and 300 nm or less.

[0009] 3. In the pattern formation method described in 1. or 2. above, the difference between the surface energy of the resist layer and the surface tension of the edge bead removal composition may be 2 mN / m or more and 15 mN / m or less.

[0010] 4. In the pattern formation method according to any one of the above 1. to 3., the surface tension of the edge bead removal composition may be 25.0 mN / m or more and 40.0 mN / m or less.

[0011] 5. In the pattern formation method according to any one of the above 1. to 4., the surface tension of the edge bead removal composition may be 27.0 mN / m or more and 36.0 mN / m or less.

[0012] 6. In the pattern formation method according to any one of the above 1. to 5., the viscosity of the edge bead removing composition may be 1 cPs or more and 10 cPs or less.

[0013] 7. In the pattern formation method according to any one of the above 1. to 6., the removal treatment in the removing step may be carried out while rotating the substrate at a speed of 500 rpm or more and 4,500 rpm or less.

[0014] 8. In the pattern formation method described in any one of 1. to 7. above, the metal compound contained in the metal-containing resist composition may include at least one selected from the group consisting of organic oxy group-containing tin compounds and organic carbonyloxy group-containing tin compounds.

[0015] 9. In the pattern formation method according to any one of the above items 1 to 8, the metal-containing resist composition may contain a metal compound represented by the following chemical formula 1 or a condensate thereof.

[0016] [ka]

[0017] In the above Chemical Formula 1, R 1is a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted arylalkyl group having 6 to 30 carbon atoms, or -L a -OR a (Here, L a is a single bond or a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, and R a is a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, R 2 ~R 4 are each independently a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, a substituted or an unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted arylalkyl group having 6 to 30 carbon atoms, -OR b and -OC(=O)R c and R 2 ~R 4 At least one of the is -OR b and OC(=O)R c is selected from In this case, R b is a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a combination thereof; R c is a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a combination thereof. [Effects of the Invention]

[0018] According to the present invention, it is possible to provide a pattern formation method that reduces the defect rate when forming a fine pattern. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a schematic diagram showing a resist coating apparatus. [Figure 2] FIG. 1 is a schematic diagram for explaining a hump. [Figure 3] 1 is an image taken by an electron microscope of a resist layer according to an embodiment after an edge bead removal composition is sprayed onto the resist layer on a substrate, as measured by a profiler device. [Figure 4] 1 is an image of a resist layer according to a comparative example, taken by an electron microscope, after an edge bead removal composition is sprayed onto the resist layer on a substrate, as measured by a profiler device. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, in describing the present invention, descriptions of functions or configurations that are already known will be omitted in order to clarify the gist of the description.

[0021] In order to clarify the present description, parts unnecessary for the description will be omitted, and the same or similar components will be designated by the same reference numerals throughout the specification. Furthermore, the size and thickness of each component shown in the drawings are arbitrarily shown for the convenience of explanation, and the present invention is not necessarily limited to those shown in the drawings.

[0022] In the drawings, the thicknesses of various layers and regions are exaggerated to clearly show them. Also, for the sake of clarity, the thicknesses of some layers and regions are exaggerated in the drawings. When a layer, film, region, plate, or other portion is "on" or "on" another portion, this includes not only when it is "directly on" the other portion, but also when there is another portion between them.

[0023] In this description, "substituted" means that a hydrogen atom is substituted with a deuterium atom, a halogen atom, a hydroxyl group, an amino group, a substituted or unsubstituted amine group having 1 to 30 carbon atoms, a nitro group, a substituted or unsubstituted silyl group having 1 to 40 carbon atoms, an alkyl group having 1 to 30 carbon atoms, a haloalkyl group having 1 to 10 carbon atoms, an alkylsilyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or a cyano group. "Unsubstituted" means that the hydrogen atom is not substituted with another substituent and remains as a hydrogen atom.

[0024] In this description, the term "alkyl group" refers to a straight-chain alkyl group unless otherwise defined. The alkyl group may be a "saturated alkyl group" that does not contain any double or triple bonds.

[0025] The alkyl group may be an alkyl group having 1 to 20 carbon atoms. More specifically, the alkyl group may be an alkyl group having 1 to 10 carbon atoms or an alkyl group having 1 to 6 carbon atoms. For example, an alkyl group having 1 to 5 carbon atoms means that the alkyl chain contains 1 to 5 carbon atoms and is selected from the group consisting of methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-pentyl, isopentyl, tert-pentyl, and neopentyl.

[0026] Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a t-butyl group, a pentyl group, and a hexyl group.

[0027] In this specification, unless otherwise defined, the term "cycloalkyl group" refers to a monovalent cyclic aliphatic hydrocarbon group. The cycloalkyl group refers to a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, etc.

[0028] As used herein, unless otherwise defined, the term "alkenyl group" refers to a straight-chain or branched-chain aliphatic hydrocarbon group that is an aliphatic unsaturated alkenyl group containing one or more double bonds.

[0029] As used herein, unless otherwise defined, the term "alkynyl group" refers to a straight-chain or branched-chain aliphatic hydrocarbon group that is an aliphatic unsaturated alkynyl group containing one or more triple bonds.

[0030] As used herein, the term "aryl group" refers to a cyclic substituent in which all elements have p-orbitals and these p-orbitals form conjugation, and includes monocyclic and fused-ring polycyclic (i.e., rings that share adjacent pairs of carbon atoms) functional groups.

[0031] More specifically, the substituted or unsubstituted aryl group having 6 to 30 carbon atoms may be, but is not limited to, a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted anthracenyl group, a substituted or unsubstituted phenanthrenyl group, a substituted or unsubstituted naphthacenyl group, a substituted or unsubstituted pyrenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted p-terphenyl group, a substituted or unsubstituted m-terphenyl group, a substituted or unsubstituted o-terphenyl group, a substituted or unsubstituted chrysenyl group, a substituted or unsubstituted benzophenanthrenyl group, a substituted or unsubstituted triphenylene group, a substituted or unsubstituted perylenyl group, a substituted or unsubstituted fluorenyl group, a substituted or unsubstituted indenyl group, or a combination thereof.

[0032] 1 is a schematic diagram showing a photoresist coating apparatus. In this specification, photoresist is also simply referred to as resist.

[0033] 1, the resist coating apparatus is provided with a substrate support 1 on which a substrate (W) is placed. The substrate support 1 includes a spin chuck or a spin coater.

[0034] The substrate support 1 rotates in a first direction at a predetermined rotation speed, and applies centrifugal force to the substrate (W). A spray nozzle 2 is located above the substrate support 1. The spray nozzle 2 is located in an area away from above the substrate (W), and moves above the substrate during the solution supply process to spray the resist solution 10. As a result, the resist solution 10 is sprayed onto the substrate surface by centrifugal force. At this time, the resist solution 10 supplied to the center of the substrate (W) is spread to the edge of the substrate (W) by centrifugal force, and part of it moves to the side surface of the substrate and the underside of the edge of the substrate.

[0035] That is, in the process of forming a resist layer on a substrate, the resist solution 10 is mainly applied to the substrate by spin coating, in which a predetermined amount of viscous resist solution 10 is supplied to the center of the substrate (W), and the resist solution 10 gradually spreads toward the edge of the substrate by centrifugal force.

[0036] Therefore, the resist is formed to a constant thickness by the rotation of the substrate support part 1.

[0037] However, as the solvent evaporates, the viscosity of the resist solution 10 increases, and a relatively large amount of resist accumulates at the edge of the substrate due to the action of surface tension. Even more serious, the resist accumulates on the underside of the edge of the substrate, which is called an edge bead 12.

[0038] A pattern forming method according to one embodiment of the present invention will be described below. Note that, hereinafter, the resist solution 10 will also be referred to as a metal-containing resist composition.

[0039] In this specification, a hump refers to a raised portion of the resist layer that occurs at the boundary between the flat area extending from the center of the resist layer toward the edge and the removed area after the edge bead is removed, as shown in the schematic diagram of Figure 2.

[0040] A pattern forming method according to one embodiment of the present invention includes the steps of: applying a metal-containing resist composition onto a substrate to form a resist layer; a removal step of applying an edge bead removal composition to the resist layer along the outer periphery of the substrate to remove the edge bead; a first heat treatment step of drying and heating the resist layer that has been subjected to the removal step; and a resist pattern forming step of exposing and developing the resist layer that has been dried and heated in the first heat treatment step to form a resist pattern. After the first heat treatment step and before the resist pattern forming step, the maximum height of humps in the resist layer in a region from the outer peripheral edge of the substrate toward the center of the substrate is 300 nm or less.

[0041] Here, the maximum height of the hump refers to the difference in level (ΔThickness) between the flat portion of the resist layer other than the hump and the most elevated portion of the hump, as shown in Figure 2b. The maximum height of the hump can be measured, for example, using a Tencor Profiler P17OF device.

[0042] The maximum value of the maximum height of the humps in a region 1 mm to 30 mm from the outer peripheral edge of the substrate toward the center is 300 nm or less, but may be 250 nm or less, 200 nm or less, 150 nm or less, or 100 nm or less. Alternatively, the minimum value of the maximum height of the humps may be 10 nm or more, or 20 nm or more. That is, the maximum height of the humps may be 10 nm to 300 nm, 20 nm to 300 nm, 10 nm to 250 nm, 20 nm to 250 nm, 10 nm to 200 nm, 20 nm to 200 nm, 10 nm to 150 nm, 20 nm to 150 nm, 10 nm to 100 nm, or 20 nm to 100 nm.

[0043] (Step of forming a resist layer) The step of forming a resist layer by applying a metal-containing resist composition onto a substrate is more specifically The method may include a step of applying a metal-containing resist composition onto a substrate by spin coating, slit coating, inkjet printing, or the like, and a step of drying the applied metal-containing resist composition to form a resist layer.

[0044] <Metal-containing resist composition> The metal compound contained in the metal-containing resist composition may be, for example, a tin compound, and the tin compound may include, for example, at least one selected from the group consisting of organic oxy group-containing tin compounds and organic carbonyloxy group-containing tin compounds.

[0045] An example of the metal compound contained in the metal-containing resist is a compound represented by the following chemical formula 1 or a condensate thereof.

[0046] [ka]

[0047] In chemical formula 1, R 1is a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted arylalkyl group having 6 to 30 carbon atoms, or -L a -OR a (Here, L a is a single bond or a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, and R a is a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, R 2 ~R 4 each independently represents a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted arylalkyl group having 6 to 30 carbon atoms, -OR b and -OC(=O)R c and R 2 ~R 4 At least one of the is -OR b and -OC(=O)R c is selected from In this case, R b is a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a combination thereof; R c is a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a combination thereof.

[0048] The metal compound contained in the metal-containing resist composition according to one embodiment may be a compound represented by the following chemical formula C or D.

[0049] [ka]

[0050] [ka]

[0051] The metal-containing resist composition according to an embodiment may include a solvent. The solvent is not particularly limited and may be any solvent known in the art for use in resist compositions, including, but not limited to, aromatic compounds (e.g., xylene, toluene), alcohols (e.g., 4-methyl-2-pentanol, 4-methyl-2-propanol, 1-butanol, methanol, isopropyl alcohol, 1-propanol), ethers (e.g., anisole, tetrahydrofuran), esters (n-butyl acetate, propylene glycol monomethyl ether acetate, ethyl acetate, ethyl lactate), ketones (e.g., methyl ethyl ketone, 2-heptanone), and mixtures thereof.

[0052] In addition, the metal-containing resist composition according to an embodiment may include at least one selected from the group consisting of a surfactant, a dispersant, a moisture absorbent, and a coupling agent.

[0053] The surfactant can improve the coating uniformity and wetting properties of the resist composition. In one embodiment, the surfactant may be, but is not limited to, a sulfate salt, a sulfonate salt, a phosphate ester, a soap, an amine salt, a quaternary ammonium salt, polyethylene glycol, an alkylphenol ethylene oxide adduct, a polyhydric alcohol, a nitrogen-containing vinyl polymer, or a combination thereof. For example, the surfactant may include an alkylbenzenesulfonate salt, an alkylpyridinium salt, polyethylene glycol, or a quaternary ammonium salt. When the resist composition includes a surfactant, the surfactant is included in an amount of about 0.001 wt % to about 3 wt % based on the total weight of the resist composition.

[0054] The dispersant may serve to uniformly disperse each component of the resist composition within the resist composition. In one embodiment, the dispersant may be selected from the group consisting of epoxy resin, polyvinyl alcohol, polyvinyl butyral, polyvinyl pyrrolidone, glucose, sodium dodecyl sulfate, sodium citrate, Examples of dispersants include, but are not limited to, oleic acid, linoleic acid, and a combination thereof. When the resist composition contains a dispersant, the dispersant is contained in an amount of about 0.001 wt % to about 5 wt % based on the total weight of the resist composition.

[0055] The moisture absorbent can prevent adverse effects of moisture on the resist composition. For example, the moisture absorbent can prevent metals contained in the resist composition from being oxidized by moisture. In one embodiment, the moisture absorbent is selected from polyoxyethylene nonylphenol ether, polyethylene glycol, polypropylene glycol, polyacrylamide, and combinations thereof, but is not limited to these. When the resist composition includes a moisture absorbent, the moisture absorbent is included in an amount of about 0.001 wt % to about 10 wt % based on the total weight of the resist composition.

[0056] The coupling agent can improve adhesion between the resist composition and an underlying film when the resist composition is coated on the underlying film. In one embodiment, the coupling agent can include a silane coupling agent. Examples of the silane coupling agent include, but are not limited to, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltrichlorosilane, vinyltris(β-methoxyethoxy)silane, 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, and trimethoxy[3-(phenylamino)propyl]silane. When the resist composition includes a coupling agent, the coupling agent is included in an amount of about 0.001 wt % to about 5 wt % based on the total weight of the resist composition.

[0057] (Removal process) Next, in the pattern formation method according to one embodiment of the present invention, a removing step is carried out in which an edge bead removing composition is applied to the resist layer along the outer periphery of the substrate to remove the edge bead.

[0058] In this process, after the edge bead removal composition is applied and the edge bead is removed, a hump occurs at the boundary between the flat area extending from the center of the resist layer toward the edge and the removed area.

[0059] The hump can cause cracks or film peeling during firing of the layer, leading to mask contamination and non-uniformity in subsequent processes. Therefore, there is a need for an edge bead removal composition that can provide a resist layer (resist film) with a better edge cut shape after application of the edge bead removal composition.

[0060] In the process of applying an edge bead removal composition according to one embodiment of the present invention, we investigated hump heights that are unlikely to cause problems in subsequent processes by adjusting the major physical properties of the resist and the edge bead removal composition, particularly the difference in viscosity and surface energy, and the process conditions for the edge bead removal process, and we also investigated an optimized method for achieving the hump heights. Here, the difference in surface energy refers to the difference between the surface energy of the resist layer and the surface tension of the edge bead removal composition.

[0061] The difference between the surface energy of the resist layer and the surface tension of the edge bead removal composition may be 2 mN / m or more and 15 mN / m or less. When the difference between the surface energy of the resist layer and the surface tension of the edge bead removal composition is 15 mN / m or less, the wetting property is low, making it difficult for the edge bead removal composition to dissolve the resist, and therefore, the cleaning power is low. In addition, a surface energy difference of 15 mN / m or less can solve the problem of low resist adhesion at the interface, which can lead to a larger hump due to the mutual repulsive force acting when the affinity at the interface is low, and the dissolved resist can remain in a solidified form near the interface without being removed. In addition, a difference of 2 mN / m or more between the surface energy of the resist layer and the surface tension of the edge bead removal composition can solve the problem of rapid penetration of the edge bead removal composition into the resist, which can cause damage to the resist layer and expansion development. In a pattern formation method according to one embodiment of the present invention, the difference between the surface energy of the resist layer and the surface tension of the edge bead removal composition is appropriate, which minimizes the impact on the resist layer and reduces metal substrate contamination, thereby meeting the demands for processing and patterning of smaller features. In addition, the difference between the surface energy of the resist layer and the surface tension of the edge bead removal composition may be 3 mN / m or more and 15 mN / m or less, 3 mN / m or more and 10 mN / m or less, 4 mN / m or more and 15 mN / m or less, or 4 mN / m or more and 10 mN / m or less.

[0062] The difference in surface energy between the resist layer and the edge bead removal composition can be measured by the method described in the examples.

[0063] The surface energy of the resist layer is 25.0 mN / m or more and 50.0 mN / m or less. The surface energy of the resist layer may be 30.0 mN / m or more and 45.0 mN / m or less. When the surface energy of the resist layer is in the above range, edge beads can be more effectively removed, and the maximum height of the hump can also be effectively suppressed. The surface energy of the resist layer can be measured by the method described in the Examples.

[0064] The surface tension of the edge bead removal composition may be 25.0 mN / m or more and 40.0 mN / m or less, 27.0 mN / m or more and 40.0 mN / m or less, 27.0 mN / m or more and 36.0 mN / m or less, or 27.0 mN / m or more and 33.0 mN / m or less. When the surface tension of the edge bead removal composition is within the above range, the edge bead can be removed more effectively, and the maximum height of the hump can also be effectively suppressed.

[0065] The surface tension of the edge bead removal composition can be measured using a K11-MK1 (KRUSS) surface tension system. More specifically, the surface tension of the edge bead removal composition can be measured by the method described in the Examples.

[0066] The viscosity of the edge bead removal composition may be 1 cPs or more and 10 cPs or less. Alternatively, the viscosity of the edge bead removal composition may be 1 cPs or more and 9 cPs or less, 1 cPs or more and 8 cPs or less, 1 cPs or more and 7 cPs or less, 1 cPs or more and 6 cPs or less, 1 cPs or more and 5 cPs or less, 1 cPs or more and 4 cPs or less, or 1 cPs or more and 3 cPs or less. Having the viscosity of the edge bead removal composition within the above range allows for more effective removal of edge beads and also effectively suppresses the maximum height of humps, thereby further reducing the rate of pattern defects.

[0067] For example, when the resist layer contains a metal compound represented by chemical formula C, the viscosity of the edge bead removal composition may be 1 cPs or more and 10 cPs or less, or 1 cPs or more and 9 cPs or less, 1 cPs or more and 8 cPs or less, 1 cPs or more and 7 cPs or less, 1 cPs or more and 6 cPs or less, 1 cPs or more and 5 cPs or less, 1 cPs or more and 4 cPs or less, or 1 cPs or more and 3 cPs or less. When the resist layer contains a metal compound represented by chemical formula C, having the viscosity of the edge bead removal composition in the above range allows for more sufficient removal of the edge bead and also allows for more effective suppression of the maximum height of the hump.

[0068] The viscosity of the edge bead removal composition can be measured using LVDV-III-UCP (manufactured by Brookfield Corp.) More specifically, the viscosity of the edge bead removal composition can be measured by the method described in the examples.

[0069] The edge bead removal composition according to one embodiment of the present invention may include an additive and a solvent. The additive and solvent are substances that are known in the art for use in edge bead removal compositions and may be selected within a range that satisfies the above-mentioned conditions. When the viscosity of the edge bead removal composition is within the above-mentioned range, the edge bead can be effectively removed and the maximum height of the hump can be reduced.

[0070] The additive contained in the edge bead removal composition according to one embodiment may be at least one of an acid compound such as carboxylic acid, phosphoric acid, phosphorous acid, phosphonic acid, sulfuric acid, or sulfonic acid, an alcohol compound, or a ketone compound. From the viewpoint of more efficiently removing the edge bead, the additive may be at least one selected from the group consisting of ethanesulfonic acid, methanesulfonic acid, butylphosphonic acid, methylphosphonic acid, trifluoroacetic acid, propionic acid, glycolic acid, difluoroacetic acid, vinylphosphonic acid, stearic acid, oleic acid, 4-nitrocatechol, tropolone, and acetylacetone.

[0071] The solvent contained in the edge bead removal composition according to one embodiment is not particularly limited, but may include at least one selected from the group consisting of ethers, alcohols, glycol ethers, aromatic hydrocarbon compounds, ketones, esters, amides, sulfoxides, and nitriles, and in particular, may include at least one selected from the group consisting of ethers, glycol ethers, esters, and alcohols. Examples of the solvent include propylene glycol methyl ether (PGME), propylene glycol methyl ether acetate (PGMEA), propylene glycol butyl ether (PGBE), ethylene glycol methyl ether, diethylene glycol ethyl methyl ether, dipropylene glycol dimethyl ether, ethanol, 2-butoxyethanol, n-propanol, isopropanol, n-butanol, isobutyl alcohol, hexanol, ethylene glycol, propylene glycol, heptanone, propylene carbonate, butylene carbonate, diethyl ether, dibutyl ether, ethyl acetate, n-butyl acetate (nBA), methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, diisopentyl ether, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, dimethyl sulfoxide, dimethylformamide, acetonitrile, diacetone alcohol, 3,3-dimethyl-2-butanone, N-methyl-2-pyrrolidone, dimethylacetamide, cyclohexanone methyl-2-hydroxy-2-methylpropionate (HBM), gamma-butyrolactone (GBL), 1-butanol (n-butanol), ethyl lactate (EL), dibutyl ether (DBE), diisopropyl ether (DIAE), acetylacetone, butyl lactate (n-butylactate), 4-methyl-2-pentanol (or methyl isobutyl carbinol (MIBC), 1-methoxy-2-propanol, 1-ethoxy-2-propanol, toluene, cyclopentanone, cyclohexanone, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, methyl pyruvate, ethyl pyruvate, butyl acetate, methyl 2-hydroxyisobutyrate, methoxybenzene, Examples of the solvent include, but are not limited to, n-butyl acetate, 1-methoxy-2-propyl acetate, methoxyethoxypropionate, ethoxyethoxypropionate, and mixtures thereof. Among these, from the viewpoint of more efficient edge bead removal, the solvent is preferably one or more selected from the group consisting of propylene glycol methyl ether (PGME), propylene glycol methyl ether acetate (PGMEA), gamma butyrolactone (GBL), ethyl lactate (EL), and 4-methyl-2-pentanol (MIBC).

[0072] The combination of the solvent and additive is not particularly limited, but when the solvent is an ether, the additive to be combined may be an acid compound (particularly, a carboxylic acid). For example, when the solvent is propylene glycol methyl ether (PGME), the additive to be combined may be one or more selected from the group consisting of propionic acid and difluoroacetic acid.

[0073] When the solvent is a glycol ether, the additive to be combined may be one selected from the group consisting of an alcohol compound and an acid compound. For example, when the solvent is propylene glycol methyl ether acetate (PGMEA), the additive may be one or more selected from the group consisting of 4-nitrocatechol, butylphosphonic acid, methylphosphonic acid, tropolone, vinylphosphonic acid, and oleic acid.

[0074] Furthermore, when the solvent is an ester, the additive to be combined may be one or more selected from an acid compound and a ketone compound, or the ester solvent may be used alone without any additive. For example, when the solvent is ethyl lactate (EL), the additive may be one or more selected from the group consisting of ethanesulfonic acid, glycolic acid, acetylacetone, and stearic acid, or ethyl lactate (EL) may be used alone without any additive. Furthermore, when the solvent is gamma butyrolactone (GBL), the additive may be one or more selected from the group consisting of trifluoroacetic acid and propionic acid.

[0075] When the solvent is an alcohol, the additive may be an acid compound. For example, when the solvent is 4-methyl-2-pentanol (MIBC), the additive may be methanesulfonic acid.

[0076] In one embodiment, the edge bead removal composition may contain 0.01 to 50% by weight of the additives described above, and 50 to 99.99% by weight of the solvent.

[0077] The edge bead removal composition may further include at least one selected from the group consisting of a surfactant, a dispersant, a moisture absorbent, and a coupling agent. When these are included, the solvent is included in the amount remaining after excluding the included components. The surfactants, dispersants, moisture absorbents, and coupling agents included in the edge bead removal composition may be appropriately selected from those described in the section on metal-containing resist compositions.

[0078] The step of applying an edge bead removal composition according to one embodiment and performing an edge bead removal process can be performed while spinning the substrate at a speed of, for example, 800 rpm to 4,500 rpm. The speed at which the substrate is rotated may be 1000 rpm to 4500 rpm, 1500 rpm to 4500 rpm, 2000 rpm to 4500 rpm, 2500 rpm to 4500 rpm, 1000 rpm to 4000 rpm, 1500 rpm to 4000 rpm, 2000 rpm to 4000 rpm, or 2500 rpm to 4000 rpm. By keeping the substrate rotation speed within the above range, the maximum height of the bumps can be reduced. In one embodiment, the time for rotating the substrate at the above speed is preferably 10 seconds or more and 100 seconds or less, and more preferably 20 seconds or more and 60 seconds or less.

[0079] In one embodiment, the process of applying the edge bead removal composition to the edge and backside of the substrate can be repeated several times to reduce the metal base contamination and resist to the desired level.

[0080] Furthermore, the area to which the edge bead removal composition of one embodiment is applied is not particularly limited as long as it is along the outer periphery of the substrate so that the edge bead can be removed. For example, the composition may be applied to a position within 30 mm from the outer periphery of the substrate toward the center, within 25 mm, within 20 mm, within 15 mm, within 10 mm, within 5 mm, within 4 mm, within 3 mm, within 2 mm, or within 1 mm.

[0081] A pattern formation method including the step of applying the edge bead removal composition of the present invention and removing the edge bead is particularly effective for removing metal-containing resists, and more specifically, for removing undesired metal residues, such as tin-based metal residues.

[0082] (First heat treatment step) Next, a first heat treatment step is performed to dry and heat the substrate on which the resist layer is formed. The first heat treatment step is not particularly limited, but can be performed at a temperature of 70°C to 170°C, or 80°C to 160°C. The heating time at this temperature is not particularly limited, but can be 30 seconds to 120 seconds, or 40 seconds to 80 seconds. During this process, the solvent is evaporated, and the resist layer is more firmly adhered to the substrate.

[0083] (Resist pattern formation process) Subsequently, the resist layer that has been subjected to the drying treatment and heat treatment in the first heat treatment step is subjected to an exposure treatment and a development treatment to form a resist pattern (resist pattern formation step).

[0084] In the exposure process, the resist layer can be selectively exposed.

[0085] For example, examples of light that can be used in the exposure process include light with short wavelengths such as activation irradiation conductor i-line (wavelength 365 nm), KrF excimer laser (wavelength 248 nm), and ArF excimer laser (wavelength 193 nm), as well as light with high-energy wavelengths such as EUV (Extreme Ultra Violet; wavelength 13.5 nm) and E-Beam (electron beam).

[0086] More specifically, the exposure light according to one embodiment may be short wavelength light having a wavelength range of 5 nm to 150 nm, or may be light having a high energy wavelength such as EUV (Extreme Ultra Violet; wavelength 13.5 nm) or E-Beam (electron beam).

[0087] In the resist pattern forming step, a negative pattern can be formed.

[0088] The exposed areas of the resist layer form a polymer through a crosslinking reaction such as condensation between metal compounds, and thus have a different solubility from the unexposed areas of the resist layer.

[0089] Subsequently, in one embodiment of the resist pattern forming process, the substrate can be subjected to a second heat treatment process. The second heat treatment process can be performed at a temperature of 90°C to 200°C. The heating time is not particularly limited, but may be 30 seconds to 120 seconds, or 40 seconds to 80 seconds. By performing the second heat treatment process, the exposed area of ​​the resist layer becomes difficult to dissolve in a developer.

[0090] Subsequently, in the development process, development can be carried out using a developer composition.

[0091] Specifically, the resist layer corresponding to the unexposed area is dissolved using a developer composition and then removed, thereby completing a resist pattern corresponding to a negative tone image.

[0092] The developer composition used in the development process may be, for example, an organic solvent, such as ketones such as methyl ethyl ketone, acetone, cyclohexanone, and 2-hydroxybenzoic acid; Examples of suitable solvents include alcohols such as 2-methyl-2-propanol, 1-butanol, isopropanol, 1-propanol, methanol, propylene glycol methyl ether (PGME), and methyl isobutyl carbinol (MIBC); esters such as propylene glycol methyl ether acetate, ethyl acetate, ethyl lactate, n-butyl acetate, methyl-2-hydroxyisobutyrate, and butyrolactone; aromatic compounds such as benzene, xylene, and toluene; and combinations thereof.

[0093] As described above, resist patterns formed by exposure to high-energy light such as EUV (Extreme Ultra Violet; wavelength 13.5 nm) and E-Beam (electron beam), as well as light having wavelengths such as i-line (wavelength 365 nm), KrF excimer laser (wavelength 248 nm), and ArF excimer laser (wavelength 193 nm), can have a thickness range of 5 nm to 100 nm. For example, the resist pattern can be formed with a thickness range of 5 nm to 90 nm, 5 nm to 80 nm, 5 nm to 70 nm, 5 nm to 60 nm, 5 nm to 50 nm, 5 nm to 40 nm, 5 nm to 30 nm, or 5 nm to 20 nm.

[0094] On the other hand, the resist pattern can have a half-pitch of about 50 nm or less, for example, 40 nm or less, for example, 30 nm or less, for example, 20 nm or less, for example, 15 nm or less, and a pitch with a line width roughness of about 10 nm or less, about 5 nm or less, about 3 nm or less, or about 2 nm or less.

[0095] Although the embodiments of the present invention have been described in detail above, it is clear that these are explanatory and exemplary and are not limiting, and the scope of the present invention should be interpreted by the appended claims. For example, the pattern formation method according to one embodiment of the present invention also includes the following embodiments. (i) applying a metal-containing resist composition onto a substrate to form a resist layer; applying an edge bead removal composition along an edge of the substrate; a heat treatment step of drying and heating; and A step of forming a resist pattern by exposure and development Including, The method for forming a pattern, wherein after applying the edge bead removing composition, the resist layer has a maximum hump height of 300 nm or less in a region of 1 mm to 30 mm from the periphery of the substrate toward the center of the substrate. (ii) The pattern formation method according to (i), wherein the maximum hump height is 10 nm to 300 nm. (iii) The pattern forming method according to (i) or (ii), wherein the difference between the surface energy of the resist layer and the surface tension of the edge bead removing composition is 2 mN / m to 15 mN / m. (iv) The pattern formation method according to any one of (i) to (iii), wherein the surface tension of the composition for removing edge beads is 25.0 mN / m to 40.0 mN / m. (v) The pattern formation method according to any one of (i) to (iv), wherein the surface tension of the composition for removing edge beads is 27.0 mN / m to 36.0 mN / m. (vi) The pattern formation method according to any one of (i) to (v), wherein the viscosity of the composition for removing edge beads is 1 to 10 cPs. (vii) The pattern forming method according to any one of (i) to (vi), wherein the step of applying the edge bead removing composition is carried out while rotating the substrate at a speed of 1,000 to 4,000 rpm. (viii) The pattern forming method according to any one of (i) to (vii), wherein the metal compound contained in the metal-containing resist includes at least one of an organic oxy group-containing tin compound and an organic carbonyloxy group-containing tin compound. (ix) The pattern forming method according to any one of (i) to (viii), wherein the metal compound contained in the metal-containing resist is represented by the following chemical formula 1:

[0096] [ka]

[0097] In the above Chemical Formula 1, R 1 is a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, a substituted or unsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C6 to C30 arylalkyl group, and -L a -OR a (Here, L a is a single bond or a substituted or unsubstituted C1 to C20 alkylene group, and R a is a substituted or unsubstituted C1-C20 alkyl group; R 2 ~R 4 are each independently a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, a substituted or unsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C6 to C30 arylalkyl group, -OR b and -OC(=O)R c and R 2 ~R 4 At least one of the is -OR b and OC(=O)R c is selected from In this case, R b is a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, a substituted or unsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C6 to C30 aryl group, or a combination thereof; R cis a hydrogen atom, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, a substituted or unsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C6 to C30 aryl group, or a combination thereof. [Example]

[0098] Hereinafter, the present invention will be described in more detail with reference to examples of the above-mentioned pattern forming method, but the technical features of the present invention are not limited to the following examples.

[0099] (Production of Metal-Containing Resist Composition) <Manufacturing example A> A metal compound having the structure of the following chemical formula C was dissolved in 4-methyl-2-pentanol at a concentration of 1 wt % and filtered through a 0.1 μm PTFE syringe filter to prepare a resist composition.

[0100] [ka]

[0101] <Manufacturing example B> A resist composition was prepared in the same manner as in Preparation Example A, except that a metal compound having the structure of the following chemical formula D was used.

[0102] [ka]

[0103] (Production of edge bead removal composition) Manufacturing Examples 1 to 22 The additives and solvents were mixed according to the compositions shown in Table 1 below, then shaken at room temperature (25°C) to completely dissolve. The mixture was then passed through a PTFE filter with a pore size of 1 μm to obtain a final edge bead removal composition. In the table, PGMEA stands for propylene glycol methyl ether acetate, EL stands for ethyl lactate, GBL stands for gamma-butyrolactone, MIBC stands for 4-methyl-2-pentanol, PGME stands for propylene glycol methyl ether, and nBA stands for n-butyl acetate.

[0104] [Table 1]

[0105] (Manufacturing of developing solutions) <Manufacturing example C> A developer was prepared by dissolving 1.0 wt % of acetic acid in PGMEA.

[0106] (Creating a resist layer) 2.0 mL of the metal-containing resist compositions from Preparation Example A and Preparation Example B was applied to an 8-inch silicon wafer, allowed to stand for 20 seconds, and then spin-coated at 1500 rpm for 30 seconds. In Table 2, the metal-containing resist composition used in Preparation Example A is designated PR(A), and the metal-containing resist composition used in Preparation Example B is designated PR(B). Next, 10 mL of an edge bead removal composition according to a Preparation Example listed in Table 2 below was applied to the wafer 1 mm above the outer periphery, rotated at the rotation speed (rpm) listed in Table 2 for 30 seconds, and then dried at 160°C for 60 seconds.

[0107] [Evaluation 1: Measurement of the surface energy (surface tension) (mN / m) of the resist layer] 2.0 mL of the metal compound-containing resist composition according to the manufacturing example was poured onto an 8-inch silicon wafer, allowed to stand for 20 seconds, then spin-coated at 1500 rpm for 30 seconds, and then heat-treated at 100°C for 60 seconds to form a resist layer.

[0108] After cleaning the surface of the resist layer, a DSA100 (KRUSS) was placed on the surface to measure the contact angle of deionized water (DIW), the contact angle of diiodomethane, and the surface energy (surface tension) calculated by the geometric mean method (OWRK method). The same measurement was repeated five times to determine the upper limit and The average value of three measurements excluding the lower limit was measured and is shown in Table 2.

[0109] [Evaluation 2: Measurement of surface tension (mN / m) of edge bead removal composition] Using a K11-MK1 (KRUSS) surface tension tester, the surface tension of the edge bead removal compositions of Preparation Examples 1 to 22 at 25°C was measured five times, and the average value of three measurements excluding the upper and lower limits was measured and shown in Table 2.

[0110] The difference in surface energy (mN / m) was calculated by subtracting the surface energy value of the resist layer obtained in Evaluation 1 from the surface tension value of the edge bead removal composition obtained in Evaluation 2. The results are shown in Table 2.

[0111] [Evaluation 3: Viscosity measurement of edge bead removal composition] The absolute viscosity of the edge bead removal compositions of Preparation Examples 1 to 22 was measured five times using LVDV-III-UCP (manufactured by Brookfield Corporation) at 25°C and Torque % 45, and the average value of three measured values ​​excluding the upper and lower limits was measured. The results are shown in Table 2.

[0112] [Rating 4: Hump rating] Fig. 2 is a schematic diagram of a hump. Referring to Fig. 2, a hump refers to a convexly raised portion at the end of a metal compound-containing resist thin film (resist layer) that is generated when an edge bead removal composition is sprayed and the edge bead is removed.

[0113] Here, the maximum height of the hump was measured. The maximum height of the hump means the difference in level (ΔThickness) between the flat part of the resist layer other than the hump and the most elevated part of the hump, as shown in Figure 2b. The maximum height of the hump was measured using a Tencor Profiler P17OF device. The measured values ​​are listed in Table 2 below.

[0114] The maximum height of the measured hump was evaluated according to the following criteria, and the results were also recorded.

[0115] A: Maximum hump height ≦100nm B: 100nm<Maximum height of hump≦300nm C: 300 nm < maximum hump height ≦ 1,000 nm D: 1,000 nm < maximum hump height [Evaluation 5: Defective rate evaluation of edge patterns] After the edge bead removal was completed, the wafers of each example were exposed to a 40 mJ dose using an ArF scanner (XT1250D manufactured by ASML) in a 1 cm x 1 cm square pattern, and then cured at 170°C for 60 seconds. Subsequently, a development process was carried out using a developer composition (Preparation Example C) at 1500 rpm for 30 seconds, and then cured at 240°C for 60 seconds.

[0116] After the curing process, the patterned wafer with the Line / Space CD pattern formed was transferred to CD-SEM measurement equipment to measure the critical dimension (CD). The critical dimension was determined as the average value after measuring 12 points on the CD-SEM image, with the target critical dimension set to 80 nm. Points that deviated from the error range (±10%) from the target critical dimension or where bridges or scombs occurred were considered to be defective shots, and the failure rate was calculated using the following formula 1. A failure rate of 1.5% or less was evaluated as good, and a failure rate of over 1.5% was evaluated as bad, as shown in Table 2.

[0117]

number

[0118] [Table 2]

[0119] Referring to Table 2, the maximum height of the humps of the patterned wafers formed in Examples 1 to 18 was measured to be lower than that of Comparative Examples 1 to 11, and therefore the pattern defect rate was lower. It can be confirmed that this is the case.

[0120] As described above, specific embodiments of the present invention have been described and illustrated, but the present invention is not limited to the described embodiments, and it will be apparent to those skilled in the art that various modifications and variations are possible without departing from the spirit and scope of the present invention. Therefore, such modifications or variations should not be understood separately from the technical spirit or perspective of the present invention, and the modified embodiments should be considered to fall within the scope of the claims of the present invention. [Explanation of symbols]

[0121] 1. Substrate support 2 spray nozzles 10 Resist solution 12 Edge bead a Resist layer b Maximum hump height c and W substrates

Claims

1. A step of applying a metal-containing resist composition onto a substrate to form a resist layer; a removing step of applying an edge bead removing composition to the resist layer along the outer periphery of the substrate to remove the edge bead; a first heat treatment step of drying and heating the resist layer that has been subjected to the removal treatment in the removal step; and a resist pattern forming step of performing an exposure process and a development process on the resist layer that has been subjected to the drying process and the heating process in the first heat treatment step to form a resist pattern, a maximum height of a hump in the resist layer in a region extending from the outer peripheral edge of the substrate toward the center of the substrate to 1 mm or more and 30 mm or less after the first heat treatment step and before the resist pattern forming step, the maximum height of the hump in the resist layer is 300 nm or less.

2. The pattern formation method according to claim 1 , wherein the maximum height of the hump is 10 nm or more and 300 nm or less.

3. 2. The pattern forming method according to claim 1, wherein a difference between the surface energy of the resist layer and the surface tension of the edge bead removal composition is 2 mN / m or more and 15 mN / m or less.

4. 2. The pattern formation method according to claim 1, wherein the surface tension of the edge bead removal composition is 25.0 mN / m or more and 40.0 mN / m or less.

5. 2. The pattern formation method according to claim 1, wherein the surface tension of the edge bead removal composition is 27.0 mN / m or more and 36.0 mN / m or less.

6. 2. The pattern formation method according to claim 1, wherein the viscosity of the edge bead removal composition is 1 cPs or more and 10 cPs or less.

7. 2. The pattern formation method according to claim 1, wherein the removing process in the removing step is performed while rotating the substrate at a speed of 800 rpm or more and 4,500 rpm or less.

8. 2. The pattern formation method according to claim 1, wherein the metal compound contained in the metal-containing resist composition comprises at least one selected from the group consisting of organic oxy group-containing tin compounds and organic carbonyloxy group-containing tin compounds.

9. 2. The pattern formation method of claim 1, wherein the metal-containing resist composition comprises a metal compound represented by the following Chemical Formula 1 or a condensate thereof: 【Chemistry 1】 In the above Chemical Formula 1, R １ represents a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms, or a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms. a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted arylalkyl group having 6 to 30 carbon atoms, or -L ａ -O-R ａ (Here, L ａ is a single bond or a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, R ａ is a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, R ２ ~R ４ each independently represents a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted arylalkyl group having 6 to 30 carbon atoms, -OR ｂ and —OC(═O)R ｃ and R ２ ~R ４ At least one of the ｂ and OC(=O)R ｃ is selected from At this time, R ｂ is a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a combination thereof; R ｃ is a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a combination thereof.

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