Resin composition for forming a phase-separated structure, and method for manufacturing a structure containing a phase-separated structure

Abstract

The present invention provides a resin composition for forming a phase-separated structure that provides a well-separated film while suppressing the occurrence of defects in the film, even when forming a thick film with a uniform film thickness and having a phase-separated structure, and a method for manufacturing a structure including a phase-separated structure using the same. [Solution] A resin composition for forming a phase-separated structure containing a block copolymer (A) and an organic solvent (S), wherein the organic solvent (S) comprises propylene glycol monomethyl ether acetate (S1) and a solvent (S2) having an ester group and a boiling point of 225°C or higher and 275°C or lower at atmospheric pressure.

Description

Technical Field

[0001] The present invention relates to a resin composition for forming a phase-separation structure and a method for manufacturing a structure including the phase-separation structure using the same.

Background Art

[0002] In recent years, with the further miniaturization of large-scale integrated circuits (LSIs), a technology for processing more delicate structures has been demanded. In response to such demands, a technology for forming a finer pattern has been developed by utilizing a phase-separation structure formed by self-organization of a block copolymer in which blocks that are mutually incompatible are bonded to each other (for example, see Patent Document 1).

[0003] The above block copolymer separates (phase-separates) in microscopic regions due to repulsion between blocks that are mutually incompatible, and by performing heat treatment or the like, a structure having a regular periodic structure is formed. Specific examples of this periodic structure include cylinders (columnar), lamellae (plate-like), spheres (spherical), and the like.

[0004] In order to utilize the phase-separation structure of the block copolymer, it is essential to form a self-organized nanostructure formed by microphase separation only in a specific region and to arrange it in a desired direction. In order to achieve such position control and orientation control, processes such as graphoepitaxy that controls the phase-separation pattern by a guide pattern and chemical epitaxy that controls the phase-separation pattern due to differences in the chemical state of the substrate have been proposed (for example, see Non-Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Non-Patent Documents

[0006]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] A film having a phase-separated structure formed by self-assembly of a block copolymer (hereinafter, the film having a phase-separated structure is also referred to as a "phase-separated film") can be used for forming a patterned etching mask. In this case, in order to secure an etching margin, the phase-separated film may need to be relatively thick (for example, a film thickness of 50 nm or more).

[0008] In addition, the phase-separated film is also required to have few defects. Here, "defects" refer to, for example, all defects detected when observing the phase-separation pattern directly from above with a scanning electron microscope or the like. These defects include, for example, defects caused by the adhesion of foreign substances or deposits such as scum (residue of the resin composition), bubbles, and dust on the surface of the phase-separation pattern after the formation of the phase-separation pattern, and defects related to the pattern shape such as bridges between line patterns and filling of the holes in contact hole patterns.

[0009] Furthermore, the resin composition for forming a phase-separated structure used for forming the phase-separated structure is applied by spin coating or the like, and it is necessary to form a film with a uniform film thickness.

[0010] The present invention has been made in view of the above circumstances, and provides a resin composition for forming a phase-separated structure that gives a coating film with a uniform film thickness and forms a thick film having a phase-separated structure, and suppresses the generation of defects in the film while providing a well-phase-separated film, and a method for manufacturing a structure including a phase-separated structure using the same.

Means for Solving the Problems

[0011] To solve the above problems, the inventors conducted extensive research and found that the above problems can be solved by using propylene glycol monomethyl ether acetate (S1) as the organic solvent (S) and a solvent (S2) having an ester group and a boiling point of 225°C or higher and 275°C or lower at atmospheric pressure, and thus completed the present invention. Specifically, the present invention provides the following.

[0012] The first embodiment is a resin composition for forming a phase-separated structure, comprising a block copolymer (A) and an organic solvent (S), The aforementioned organic solvent (S) is a resin composition for forming a phase separation structure, comprising propylene glycol monomethyl ether acetate (S1) and a solvent (S2) having an ester group and a boiling point of 225°C or higher and 275°C or lower at atmospheric pressure.

[0013] A second embodiment is a method for manufacturing a structure having a phase-separated structure, comprising: applying a resin composition for forming a phase-separated structure according to the first embodiment onto a support to form a layer containing a block copolymer; and phase-separating the layer containing the block copolymer. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a resin composition for forming a phase-separated structure that provides a well-separated film while suppressing the occurrence of defects in the film, even when forming a thick film having a phase-separated structure with a uniform film thickness, and a method for manufacturing a structure including a phase-separated structure using the same. [Brief explanation of the drawing]

[0015] [Figure 1] This is a schematic process diagram illustrating one embodiment of a method for manufacturing a structure including a phase-separated structure. [Figure 2] This is a diagram illustrating one embodiment of an optional process. [Modes for carrying out the invention]

[0016] The embodiments of the present invention will be described in detail below, but the present invention is not limited to the embodiments described below and can be implemented with appropriate modifications within the scope of the object of the present invention.

[0017] ≪Resin composition for forming phase-separated structure≫ The resin composition for forming a phase-separated structure according to the first embodiment contains a block copolymer (A) and an organic solvent (S). The organic solvent (S) includes propylene glycol monomethyl ether acetate (S1) and a solvent (S2) having an ester group and a boiling point of 225°C or higher and 275°C or lower at atmospheric pressure. This allows for uniform film formation, and even when forming a thick film with a phase-separated structure, it is possible to form a phase-separated structure while suppressing the occurrence of defects in the film.

[0018] Although the reason for these effects is not entirely clear, it is thought that in layers containing block copolymers formed by the phase-separated structure-forming resin composition of the first embodiment, the solvent (S2) tends to remain, improving the mobility of the block copolymers during annealing, thereby suppressing the occurrence of defects. Furthermore, because it also contains propylene glycol monomethyl ether acetate (S1), it is thought that the film formation becomes more uniform.

[0019] <Block copolymer (A)> Block copolymer (A) is a polymer formed by the bonding of multiple types of blocks. The blocks constituting block copolymer (A) may consist of two types or three or more types. The multiple types of blocks constituting block copolymer (A) are not particularly limited as long as a combination occurs in which phase separation occurs, but it is preferable that the combination consists of blocks that are incompatible with each other.

[0020] The block copolymer (A) preferably contains at least one selected from the group consisting of block copolymer (A1), block copolymer (A2), and block copolymer (A3).

[0021] Block copolymer (A1) comprises block (A1-1) and block (A1-2). Block (A1-1) is composed of a polymer consisting of a repeating structure of a constituent unit represented by the following formula (a1). Block (A1-2) is composed of a polymer consisting of a repeating structure of a constituent unit represented by the following formula (a3). Block copolymer (A2) comprises block (A2-1) and block (A2-2). Block (A2-1) is composed of a polymer consisting of a repeating structure of constituent units represented by the following formula (a1). Block (A2-2) is composed of a random copolymer consisting of a structure in which constituent units represented by the following formula (a2) and constituent units represented by the following formula (a3) ​​are randomly arranged. Block copolymer (A3) comprises block (A3-1), block (A3-2), and block (A3-3). Block (A3-1) is composed of a polymer consisting of a repeating structure of constituent units represented by the following formula (a1). Block (A3-2) is composed of a polymer consisting of a repeating structure of constituent units represented by the following formula (a2). Block (A3-3) is composed of a polymer consisting of a repeating structure of constituent units represented by the following formula (a3). [ka] (In formula (a1), R a1 is an alkyl group which may have substituents, and n is an integer between 0 and 5, In formula (a2), R a2 R is an alkyl group which may have a silyl group, a fluorine atom, a carboxyl group, an amino group, a hydroxyl group, or a phosphate group. a3 This is an alkylene group which may have a hydroxyl group, In formula (a3), R a4 is an alkyl group which may have substituents, In formulas (a1) to (a3), R a (This is a hydrogen atom or a methyl group.)

[0022] [Constituent units represented by formula (a1)] R a1The number of carbon atoms of the alkyl group as [specified] is preferably 1 or more and 5 or less. However, the number of carbon atoms of the substituent is not included in this number of carbon atoms. R a1 Examples of the alkyl group as [specified] include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, and a tert-butyl group. R a1 Examples of the substituent that the alkyl group as [specified] may have include an alkoxy group, an alkylsilyl group, an alkylsilyloxy group, an alkoxysilyl group, and a halogen atom.

[0023] When n is an integer of 2 or more, the plurality of R a1 may be the same or different from each other.

[0024] [Structural unit represented by formula (a2)] R a2 The number of carbon atoms of the alkyl group as [specified] is preferably 1 or more and 20 or less, more preferably 1 or more and 10 or less, and even more preferably 1 or more and 5 or less. R a2 The alkyl group as [specified] may be linear or branched, but is preferably linear. R a2 Examples of the alkyl group as [specified] include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, and the like. Among these, a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, or an n-octyl group is preferable, and a methyl group, an ethyl group, or an n-propyl group is more preferable.

[0025] R a2 When the alkyl group as [specified] has a silyl group, a fluorine atom, a carboxy group, an amino group, a hydroxy group, or a phosphoric acid group, the silyl group or the like is a substituent that replaces a hydrogen atom of the alkyl group. The number of hydrogen atoms to be replaced may be 1 or more and 5 or less, or 1 or more and 3 or less. R a2Examples of silyl groups that the alkyl group may have include monoalkylsilyl groups, dialkylsilyl groups, and alkylsilyl groups such as trialkylsilyl groups. Among these, trialkylsilyl groups are preferred. The number of carbon atoms in the alkyl group in the alkylsilyl group is preferably 1 to 5, more preferably 1 to 3. Examples of alkyl groups in the alkylsilyl group include methyl groups, ethyl groups, n-propyl groups, isopropyl groups, n-butyl groups, isobutyl groups, sec-butyl groups, tert-butyl groups, and n-pentyl groups. Among these, methyl groups or ethyl groups are preferred, and methyl groups are more preferred.

[0026] R a3 The number of carbon atoms in the alkylene group is preferably 2 or more, more preferably 3 or more. Furthermore, the number of carbon atoms in the alkylene group is preferably 10 or less, more preferably 8 or less, even more preferably 5 or less, and particularly preferably 4 or less, from the viewpoint of phase separation performance. The number of carbon atoms in the alkylene group is most preferably 3. a3 The alkylene group may be linear or branched, but linear is preferred.

[0027] R a3 When the alkylene group has hydroxyl groups, the number of hydroxyl groups is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1.

[0028] [Constituent units represented by formula (a3)] R a4 The number of carbon atoms in the alkyl group is preferably 1 to 10, more preferably 1 to 5. However, this number of carbon atoms does not include the number of carbon atoms in the substituents. a4 Examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl groups. Among these, the methyl group is preferred.

[0029] [Block copolymer (A1)] In block copolymer (A1), the ratio of the number of moles of the constituent units of block (A1-1) to the total number of moles of the constituent units of block (A1-2) is preferably 20 mol% to 80 mol%, more preferably 30 mol% to 70 mol%, and even more preferably 40 mol% to 60 mol%.

[0030] In block copolymer (A1), the ratio of moles of constituent units of block (A1-2) to the total number of moles of constituent units of block (A1-2) is preferably 20 mol% to 80 mol%, more preferably 30 mol% to 70 mol%, and even more preferably 40 mol% to 60 mol%.

[0031] The block copolymer (A1) may have other blocks in addition to block (A1-1) and block (A1-2). In a preferred embodiment, the block copolymer (A1) is a diblock copolymer composed of block (A1-1) and block (A1-2).

[0032] [Block copolymer (A2)] In block copolymer (A2), the ratio of moles of constituent units of block (A2-1) to the total number of moles of constituent units of block (A2-2) is preferably 20 mol% to 80 mol%, more preferably 30 mol% to 70 mol%, and even more preferably 40 mol% to 60 mol%.

[0033] In block copolymer (A2), the ratio of moles of block (A2-2) to the total number of moles of block (A2-2) is preferably 20 mol% to 80 mol%, more preferably 30 mol% to 70 mol%, and even more preferably 40 mol% to 60 mol%.

[0034] In block (A2-2), the ratio of the number of moles of the constituent unit represented by formula (a2) to the total number of moles of the constituent unit represented by formula (a3) ​​is preferably 90 mol% or less, more preferably 30 mol% or less, and even more preferably 1 mol% or more and 10 mol% or less.

[0035] The block copolymer (A2) may have other blocks in addition to block (A2-1) and block (A2-2). In a preferred embodiment, the block copolymer (A2) is a diblock copolymer composed of block (A2-1) and block (A2-2).

[0036] [Block copolymer (A3)] In block copolymer (A3), the ratio of moles of constituent units of block (A3-1) to the total number of moles of constituent units of block (A3-1), block (A3-2), and block (A3-3) is preferably 20 mol% to 80 mol%, more preferably 30 mol% to 70 mol%, and even more preferably 40 mol% to 60 mol%.

[0037] In block copolymer (A3), the ratio of moles of constituent units of block (A3-2) to the total number of moles of constituent units of block (A3-1), block (A3-2), and block (A3-3) is preferably 0.5 mol% to 8 mol%, more preferably 1 mol% to 7 mol%, and even more preferably 1.5 mol% to 6 mol%.

[0038] In block copolymer (A3), the ratio of moles of constituent units of block (A3-3) to the total number of moles of constituent units of block (A3-1), block (A3-2), and block (A3-3) is preferably 10 mol% to 70 mol%, more preferably 15 mol% to 65 mol%, and even more preferably 20 mol% to 60 mol%.

[0039] The block copolymer (A3) preferably has blocks (A3-1), block (A3-2), and block (A3-3) in that order, or blocks (A3-1), block (A3-3), and block (A3-2) in that order.

[0040] The block copolymer (A3) may have other blocks in addition to blocks (A3-1), (A3-2), and (A3-3). In a preferred embodiment, the block copolymer (A3) is a triblock copolymer composed of blocks (A3-1), (A3-2), and (A3-3).

[0041] The number-average molecular weight (Mn) of the block copolymer (A) is not particularly limited, but is preferably 10,000 to 300,000, more preferably 20,000 to 200,000, and even more preferably 30,000 to 100,000. The molecular weight dispersion (Mw / Mn) of the block copolymer (A) is preferably 1.0 or more and 1.5 or less, more preferably 1.0 or more and 1.4 or less, and even more preferably 1.0 or more and 1.3 or less. In this specification, "number-average molecular weight" (Mn) and "weight-average molecular weight" (Mw) refer to the number-average molecular weight and weight-average molecular weight in terms of standard polystyrene, determined by gel permeation chromatography (GPC), unless otherwise specified. The unit (gmol) is used for the value of Mn or Mw. -1 If a parentheses is present, the value represents the molar mass.

[0042] <Organic solvent (S)> The organic solvent (S) includes propylene glycol monomethyl ether acetate (S1) and a solvent (S2) having an ester group and a boiling point of 225°C or higher and 275°C or lower at atmospheric pressure.

[0043] [Solvent (S2)] The boiling point of the solvent (S2) at atmospheric pressure is 225°C or higher and 275°C or lower, preferably 227°C or higher and 273°C or lower, and more preferably 229°C or higher and 271°C or lower. A boiling point of 225°C or higher at atmospheric pressure can suppress the occurrence of defects. A boiling point of 275°C or lower at atmospheric pressure can enable uniform film formation.

[0044] The number of ester groups in the solvent (S2) is not particularly limited, but is preferably 1 to 3, and more preferably 1 or 2.

[0045] As the solvent (S2), a compound represented by the following formula (s2-1) is preferred. R S1 -X S1 -R S2 -X S2 -R S3 (s2-1) (In formula (s2-1), R S1 R is a hydrogen atom or an alkyl group which may have substituents, S2 R is a single bond or an alkylene group which may have substituents, S3 X is an alkyl group which may have substituents, S1 X is a single bond or an ester group. S2 (This is an ester group.)

[0046] R S1 , and R S3 The number of carbon atoms in the alkyl group is preferably 1 to 10, more preferably 1 to 5, and even more preferably 1 to 3. However, this number of carbon atoms does not include the number of carbon atoms in the substituents. S1 , and R S3 The alkyl group may be linear or branched, but linear is preferred. S1, and R S3 Examples of alkyl groups include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, and n-decyl group. Among these, methyl group, ethyl group, n-propyl group, n-butyl group, or n-pentyl group are preferred, and methyl group or ethyl group are more preferred.

[0047] R S1 , and R S3 Substituents that the alkyl group may have include silyl groups, fluorine atoms, fluorinated alkyl groups, acyl groups, and alkoxy groups. Examples of silyl groups include trialkylsilyl groups such as trimethylsilyl and triethylsilyl groups. Examples of fluorinated alkyl groups include trifluoromethyl groups. Examples of acyl groups include acetyl groups. Examples of alkoxy groups include methoxy and ethoxy groups.

[0048] R S2 The number of carbon atoms in the alkylene group is preferably 1 to 30, more preferably 2 to 20, and even more preferably 3 to 10. S2 The alkylene group may be linear or branched, but linear is preferred. S2 Examples of alkylene groups include methylene, ethane-1,2-diyl, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, and decane-1,10-diyl. S2 The substituents that the alkylene group may have include R S1 , and R S3 Examples of substituents similar to those that the alkyl group may have include.

[0049] X S1 , and X S2In this case, the orientation of the ester group is not particularly limited and can be either -C(=O)-O- or -OC(=O)-.

[0050] Examples of solvents (S2) include ethyl decanoate (boiling point 243°C), ethyl undecanoate (boiling point 260°C), dimethyl suberate (boiling point 270°C), 1,4-diacetoxybutane (boiling point 230°C), and dibutyl oxalate (boiling point 246°C). These may be used individually or in combination of two or more.

[0051] [Solvent (S3)] The organic solvent (S) may include propylene glycol monomethyl ether acetate (S1) and a solvent other than solvent (S2) (S3).

[0052] Examples of solvents (S3) include lactones such as γ-butyrolactone; ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-pentyl ketone, methyl isopentyl ketone, and 2-heptanone; polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol; monoacetates of polyhydric alcohols such as ethylene glycol monoacetate, diethylene glycol monoacetate, and propylene glycol monoacetate; and compounds having ether bonds such as monoalkyl ethers, monoethyl ethers, monopropyl ethers, monobutyl ethers, or monophenyl ethers of the aforementioned polyhydric alcohols or monoacetates of the aforementioned polyhydric alcohols. Examples include derivatives of polyhydric alcohols [of which propylene glycol monomethyl ether (PGME) is preferred]; cyclic ethers such as dioxane, monoacetates of polyhydric alcohols such as methyl lactate, ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, and ethyl ethoxypropionate, and esters other than the aforementioned derivatives of polyhydric alcohols; and aromatic organic solvents such as anisole, ethyl benzyl ether, cresyl methyl ether, diphenyl ether, dibenzyl ether, phenethole, butylphenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, and mesitylene. These may be used individually or in combination of two or more.

[0053] The organic solvent (S) is appropriately set according to the coating thickness so that the concentration of the resin composition for forming the phase separation structure is at a concentration that can be applied. Generally, the organic solvent (S) is used so that the solid content concentration of the resin composition for forming the phase separation structure is in the range of 0.2% by mass or more and 70% by mass or less, preferably 0.2% by mass or more and 50% by mass or less.

[0054] The ratio of propylene glycol monomethyl ether acetate (S1) to the total mass of the organic solvent (S) is preferably 40% to 95% by mass, more preferably 45% to 90% by mass, and even more preferably 50% to 85% by mass. Within this numerical range, the desired effect is more likely to be obtained.

[0055] The ratio of the mass of solvent (S2) to the total mass of organic solvent (S) is preferably 5% to 60% by mass, more preferably 10% to 55% by mass, and even more preferably 15% to 50% by mass. Within this numerical range, the desired effect is more likely to be obtained.

[0056] The ratio of the mass of solvent (S2) to the total mass of propylene glycol monomethyl ether acetate (S1) is preferably 5% to 60% by mass, more preferably 10% to 55% by mass, and even more preferably 15% to 50% by mass. A ratio of 5% or more by mass tends to suppress the occurrence of defects. A ratio of 60% or less by mass facilitates uniform film formation.

[0057] The ratio of the total mass of propylene glycol monomethyl ether acetate (S1) and the total mass of solvent (S2) to the total mass of organic solvent (S) is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more, from the standpoint of easily obtaining the desired effect.

[0058] <Other ingredients> The resin composition for forming phase-separated structures may contain components other than the block copolymer (A) and the organic solvent (B). Other components include other resins such as homopolymers, surfactants, dissolution inhibitors, plasticizers, stabilizers, colorants, anti-halation agents, dyes, sensitizers, base enhancers, and basic compounds.

[0059] ≪Method for manufacturing a structure containing a phase-separated structure≫ A method for manufacturing a structure including a phase-separated structure according to a second embodiment includes: applying a resin composition for forming a phase-separated structure according to a first embodiment onto a support to form a layer containing a block copolymer (hereinafter referred to as "step (i)"), and phase-separating the layer containing the block copolymer (hereinafter referred to as "step (ii)"). The manufacturing method for a structure including such a phase-separated structure will be described in detail below with reference to Figure 1. However, the manufacturing method for a structure including a phase-separated structure is not limited to the embodiment specifically shown in Figure 1.

[0060] Figure 1 shows an example of one embodiment of a method for manufacturing a structure including a phase-separated structure. In the embodiment shown in Figure 1, first, a primer is applied to the support 1 to form a primer layer 2 (Figure 1(I)). Next, a resin composition for forming a phase-separated structure is applied to the primer layer 2 to form a layer containing a block copolymer (BCP layer) 3 (Figure 1(II); step (i) above). Next, the BCP layer 3 is heated and annealed to separate it into phases 3a and 3b (Figure 1(III); step(ii)). According to the manufacturing method of this embodiment, that is, the manufacturing method having steps (i) and (ii), a structure 3' including a phase separation structure is manufactured on a support 1 on which a primer layer 2 is formed.

[0061] <Process (i)> In step (i), a resin composition for forming a phase separation structure is applied to the support 1 to form a BCP layer 3. In the embodiment shown in Figure 1, first, a primer is applied to the support 1 to form a primer layer 2. By providing a primer layer 2 on the support 1, a hydrophilic-hydrophobic balance can be achieved between the surface of the support 1 and the layer containing the block copolymer (BCP layer) 3. In other words, if the primer layer 2 contains a resin component having a structural unit that constitutes one of the blocks of the block copolymer, the adhesion between the phase of the BCP layer 3 consisting of that block and the support 1 is increased. Consequently, the phase separation of the BCP layer 3 facilitates the formation of a phase-separated structure oriented perpendicular to the surface of the support 1.

[0062] Primer: A resin composition can be used as a primer. The resin composition for the primer can be appropriately selected from conventionally known resin compositions used for thin film formation, depending on the type of block constituting the block copolymer. The resin composition for the primer may be, for example, a thermopolymerizable resin composition, or a photosensitive resin composition such as a positive-type resist composition or a negative-type resist composition. Alternatively, a compound may be used as a surface treatment agent, and a non-polymerizable film formed by coating the compound may be used as the primer layer. For example, a siloxane-based organic monolayer formed with phenethyltrichlorosilane, octadecyltrichlorosilane, hexamethyldisilazane, etc., as a surface treatment agent can also be suitably used as the primer layer.

[0063] Examples of such resin compositions include resin compositions containing resins that have all of the constituent units that make up each block constituting the block copolymer, and resin compositions containing resins that have all of the constituent units that have high affinity with each of the blocks constituting the block copolymer. As a resin composition for a primer, it is preferable to use, for example, a composition containing a resin having both styrene and methyl methacrylate as constituent units, or a compound or composition containing both a part with high affinity for styrene, such as an aromatic ring, and a part with high affinity for methyl methacrylate (such as a highly polar functional group). Resins containing both styrene and methyl methacrylate as constituent units include random copolymers of styrene and methyl methacrylate, and alternating polymers of styrene and methyl methacrylate (polymers in which each monomer is copolymerized alternately). Furthermore, a composition containing both a moiety highly compatible with styrene and a moiety highly compatible with methyl methacrylate is, for example, a composition containing a resin obtained by polymerizing at least a monomer having an aromatic ring and a monomer having a highly polar functional group. Examples of monomers having an aromatic ring include aryl groups, such as phenyl groups, biphenyl groups, fluorenyl groups, naphthyl groups, anthryl groups, and phenanthryl groups, which are aromatic hydrocarbon rings with one hydrogen atom removed, or heteroaryl groups, in which some of the carbon atoms constituting the ring of these groups are substituted with heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. Examples of monomers having a highly polar functional group include monomers having trimethoxysilyl groups, trichlorosilyl groups, epoxy groups, glycidyl groups, carboxyl groups, hydroxyl groups, cyano groups, and hydroxyalkyl groups, in which some of the hydrogen atoms of an alkyl group are substituted with hydroxyl groups. Other examples of compounds containing both a moiety highly compatible with styrene and a moiety highly compatible with methyl methacrylate include compounds containing both an aryl group and a highly polar functional group, such as phenethyltrichlorosilane, and compounds containing both an alkyl group and a highly polar functional group, such as alkylsilane compounds.

[0064] The resin composition for the primer can be manufactured by dissolving the aforementioned resin in a solvent. Such a solvent can be any solvent that can dissolve each component used to form a homogeneous solution, and examples include solvents similar to the organic solvent components exemplified in the description of the resin composition for forming a phase separation structure.

[0065] The support 1 is not particularly limited in type, as long as a resin composition can be applied to its surface. Examples include substrates made of inorganic materials such as silicon, metals (copper, chromium, iron, aluminum, etc.), glass, titanium oxide, silica, and mica; substrates made of oxides such as SiO2; substrates made of nitrides such as SiN; substrates made of oxidized nitrides such as SiON; and substrates made of organic materials such as acrylic resin, polystyrene, cellulose, cellulose acetate, and phenolic resin. Among these, silicon substrates (Si substrates) or metal substrates are preferred, Si substrates or copper substrates (Cu substrates) are more preferred, and Si substrates are particularly preferred. The size and shape of the support 1 are not particularly limited. The support 1 does not necessarily need to have a smooth surface, and various shapes of substrates can be appropriately selected. Examples include substrates with curved surfaces, flat plates with uneven surfaces, and substrates in the shape of thin flakes.

[0066] The surface of the support 1 may be provided with an inorganic and / or organic film. Examples of inorganic films include inorganic anti-reflective coatings (inorganic BARC). Examples of organic films include organic anti-reflective coatings (organic BARC). Inorganic films can be formed, for example, by coating an inorganic anti-reflective film composition, such as a silicon-based material, onto a support and then firing it. Organic films can be formed, for example, by applying an organic film-forming material, which is obtained by dissolving resin components constituting the film in an organic solvent, onto a substrate using a spinner or the like, and then baking it under heating conditions of preferably 200°C to 300°C, preferably 30 seconds to 300 seconds, and more preferably 60 seconds to 180 seconds. This organic film-forming material does not necessarily need to be sensitive to light or electron beams, like a resist film; it may or may not be sensitive. Specifically, resists and resins commonly used in the manufacture of semiconductor devices and liquid crystal display devices can be used. Furthermore, to form an organic film pattern, it is preferable that the organic film forming material is capable of forming an organic film that can be etched, particularly dry etched, by etching an organic film using a pattern made of block copolymer formed by processing the BCP layer 3. In particular, it is preferable that the material is capable of forming an organic film that can be etched, such as by oxygen plasma etching. Such an organic film forming material may be a material that has been conventionally used to form organic films such as organic BARC. Examples include the ARC series from Nissan Chemical Industries, Ltd., the AR series from Rohm & Haas, and the SWK series from Tokyo Ohka Kogyo Co., Ltd.

[0067] The method for applying the primer onto the support 1 to form the primer layer 2 is not particularly limited and can be formed by conventionally known methods. For example, a primer layer 2 can be formed by applying a primer onto a support 1 using a conventionally known method such as spin coating or using a spinner to form a coating film, and then drying it. The drying method for the coating film can be any method that allows the solvent contained in the primer to volatilize, such as baking. In this case, the baking temperature is preferably 80°C to 300°C, more preferably 180°C to 270°C, and even more preferably 220°C to 250°C. The baking time is preferably 30 seconds to 600 seconds, and more preferably 60 seconds to 600 seconds. The thickness of the primer layer 2 after the coating film has dried is preferably between 5 nm and 100 nm.

[0068] Before forming the primer layer 2 on the support 1, the surface of the support 1 may be pre-cleaned. Cleaning the surface of the support 1 improves the applicability of the primer. Conventional known methods can be used for the cleaning process, such as oxygen plasma treatment, ozone oxidation treatment, acid-alkali treatment, and chemical modification treatment.

[0069] After forming the primer layer 2, the primer layer 2 may be rinsed with a rinsing solution such as a solvent if necessary. This rinsing removes uncrosslinked portions and other imperfections in the primer layer 2, thereby improving the affinity with at least one block constituting the block copolymer and facilitating the formation of a phase separation structure consisting of a cylinder structure oriented perpendicular to the surface of the support 1. The rinsing solution only needs to be able to dissolve the uncrosslinked portion, and solvents such as propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), ethyl lactate (EL), or commercially available thinners can be used. Furthermore, after the cleaning, a post-bake may be performed to evaporate the rinse solution. The temperature conditions for this post-bake are preferably 80°C to 300°C, and more preferably 100°C to 270°C. The baking time is preferably 30 seconds to 500 seconds, and more preferably 60 seconds to 240 seconds. The thickness of the primer layer 2 after such post-bake is preferably about 1 nm to 10 nm, and more preferably about 2 nm to 7 nm.

[0070] Next, a layer containing a block copolymer (BCP layer) 3 is formed on top of the primer layer 2. The method for forming the BCP layer 3 on the primer layer 2 is not particularly limited, and includes, for example, a conventionally known method such as using spin coating or a spinner to apply the resin composition for forming the phase separation structure of the above embodiment onto the primer layer 2 to form a coating film and then dry it.

[0071] The thickness of the BCP layer 3 should be sufficient for phase separation to occur. Considering the type of support 1, the structural period size of the formed phase separation structure, or the uniformity of the nanostructure, a thickness of 10 nm to 100 nm is preferred, and 20 nm to 80 nm is more preferred. In the present invention, even when forming a thick phase separation film, the occurrence of defects in the phase separation film can be suppressed, so a thickness of 30 nm to 80 nm is even more preferred, 40 nm to 80 nm is particularly preferred, and 50 nm to 80 nm is most preferred.

[0072] <Process (ii)> In step (ii), the BCP layer 3 formed on the support 1 is phase-separated. By heating the support 1 after step (i) and performing an annealing treatment, a phase-separated structure is formed such that at least a portion of the surface of the support 1 is exposed by selective removal of the block copolymer. That is, a structure 3' containing a phase-separated structure divided into phase 3a and phase 3b is manufactured on the support 1. The temperature conditions for the annealing treatment are preferably above the glass transition temperature of the block copolymer used, but below the thermal decomposition temperature. For example, if the block copolymer is polystyrene-polymethyl methacrylate (PS-PMMA) block copolymer (mass average molecular weight 5,000 to 100,000), then 180°C to 270°C is preferred. The heating time is preferably 30 seconds to 3,600 seconds. Furthermore, the annealing process is preferably carried out in a low-reactivity gas such as nitrogen.

[0073] <Optional process> The method for manufacturing a structure including a phase-separated structure is not limited to the embodiments described above, and may include steps other than steps (i) and (ii) (optional steps).

[0074] Such optional steps include a step of selectively removing a phase consisting of at least one type of block from among the blocks constituting the block copolymer from the BCP layer 3 (hereinafter referred to as "step (iii)"), a guide pattern formation step, and the like.

[0075] Regarding process (iii): In step (iii), a phase consisting of at least one type of block from among the blocks constituting the block copolymer is selectively removed from the BCP layer formed on the base coat layer 2. This forms a fine pattern (polymer nanostructure).

[0076] Methods for selectively removing the block-based phase include treating the BCP layer with oxygen plasma or hydrogen plasma. For example, after phase separation of a BCP layer containing block copolymer (A1), the BCP layer is subjected to oxygen plasma treatment or hydrogen plasma treatment, thereby selectively removing the phase consisting of block (A1-1) while selectively removing the phase consisting of block (A1-2).

[0077] Figure 2 shows an example of one embodiment of process (iii). In the embodiment shown in Figure 2, the structure 3' manufactured on the support 1 in step (ii) is subjected to oxygen plasma treatment, thereby selectively removing phase 3a and forming a pattern (polymer nanostructure) consisting of separated phases 3b. In this case, phase 3b is a phase consisting of a first block, and phase 3a is a phase consisting of a second block.

[0078] As described above, the support 1, on which a pattern has been formed by the phase separation of the BCP layer 3 made of the block copolymer, can be used as is, but the shape of the pattern (polymer nanostructure) on the support 1 can also be changed by further heating. The heating temperature should preferably be above the glass transition temperature of the block copolymer used, and below its thermal decomposition temperature. Furthermore, heating is preferably carried out in a low-reactivity gas such as nitrogen.

[0079] • Regarding the guide pattern formation process In a method for manufacturing a structure including a phase-separated structure, a step of providing a guide pattern on the primer layer (guide pattern formation step) may be included between the above-described steps (i) and (ii). This makes it possible to control the arrangement structure of the phase-separated structure. For example, even with a block copolymer that forms a random fingerprint-like phase separation structure when no guide pattern is provided, a phase separation structure oriented along the grooves can be obtained by providing a groove structure of the resist film on the surface of the undercoat layer. Guide patterns may be provided on the undercoat layer 2 based on this principle. Furthermore, if the surface of the guide pattern has affinity with any of the blocks constituting the block copolymer, it becomes easier to form a phase separation structure consisting of a cylinder structure oriented perpendicular to the support surface.

[0080] Guide patterns can be formed, for example, using a resist composition. The resist composition for forming the guide pattern can be selected from among resist compositions and modifications thereof commonly used for forming resist patterns, and can be appropriately chosen to have affinity with any of the blocks constituting the block copolymer. The resist composition may be either a positive-type resist composition that forms a positive-type pattern in which the exposed portion of the resist film is dissolved and removed, or a negative-type resist composition that forms a negative-type pattern in which the unexposed portion of the resist film is dissolved and removed, but a negative-type resist composition is preferred. As a negative-type resist composition, for example, a resist composition containing an acid generator and a base component whose solubility in a developer containing an organic solvent is reduced by the action of the acid, and the base component having a resin component whose polarity increases when it decomposes by the action of the acid, is preferred. After the BCP composition is poured onto the primer layer on which the guide pattern has been formed, an annealing treatment is performed to induce phase separation. For this reason, the resist composition used to form the guide pattern is preferably a composition that can form a resist film with excellent solvent resistance and heat resistance.

[0081] As described above, the inventors provide the following (1) to (8). (1) A resin composition for forming a phase-separated structure, comprising a block copolymer (A) and an organic solvent (S), A resin composition for forming a phase-separated structure, wherein the organic solvent (S) comprises propylene glycol monomethyl ether acetate (S1) and a solvent (S2) having an ester group and a boiling point of 225°C or higher and 275°C or lower at atmospheric pressure. (2) The resin composition for forming a phase separation structure according to (1), wherein the ratio of the mass of the solvent (S2) to the sum of the mass of the propylene glycol monomethyl ether acetate (S1) and the mass of the solvent (S2) is 5% by mass or more and 60% by mass or less. (3) The resin composition for forming a phase separation structure according to (1) or (2), wherein the ratio of the total mass of the propylene glycol monomethyl ether acetate (S1) and the total mass of the solvent (S2) to the total mass of the solvent (S) is 90% by mass or more. (4) The resin composition for forming a phase separation structure according to any one of (1) to (3), wherein the solvent (S2) is a compound represented by the following formula (s2-1). R S1 -X S1 -R S2 -X S2 -R S3 (s2-1) (In formula (s2-1), R S1 R is a hydrogen atom or an alkyl group which may have substituents, S2 R is a single bond or an alkylene group which may have substituents, S3 X is an alkyl group which may have substituents, S1 X is a single bond or an ester group. S2 (This is an ester group.) (5) The block copolymer (A) comprises at least one selected from the group consisting of block copolymer (A1), block copolymer (A2), and block copolymer (A3), The block copolymer (A1) comprises block (A1-1) and block (A1-2), wherein block (A1-1) is composed of a polymer consisting of a repeating structure of a structural unit represented by the following formula (a1), and block (A1-2) is composed of a polymer consisting of a repeating structure of a structural unit represented by the following formula (a3). The block copolymer (A2) comprises block (A2-1) and block (A2-2), wherein block (A2-1) is composed of a polymer consisting of a repeating structure of structural units represented by the following formula (a1), and block (A2-2) is composed of a random copolymer having a structure in which structural units represented by the following formula (a2) and structural units represented by the following formula (a3) ​​are randomly arranged. The phase separation structure forming resin composition according to any one of (1) to (4), wherein the block copolymer (A3) comprises block (A3-1), block (A3-2), and block (A3-3), wherein block (A3-1) is composed of a polymer consisting of a repeating structure of a structural unit represented by the following formula (a1), block (A3-2) is composed of a polymer consisting of a repeating structure of a structural unit represented by the following formula (a2), and block (A3-3) is composed of a polymer consisting of a repeating structure of a structural unit represented by the following formula (a3). [ka] (In formula (a1), R a1 is an alkyl group which may have substituents, and n is an integer between 0 and 5, In formula (a2), R a2 R is an alkyl group which may have a silyl group, a fluorine atom, a carboxyl group, an amino group, a hydroxyl group, or a phosphate group. a3 This is an alkylene group which may have a hydroxyl group, In formula (a3), R a4 is an alkyl group which may have substituents, In formulas (a1) to (a3), R a (This is a hydrogen atom or a methyl group.) (6) Applying a resin composition for forming a phase separation structure according to any one of (1) to (5) onto a support to form a layer containing a block copolymer, The process involves separating the layer containing the aforementioned block copolymer, A method for manufacturing a structure having a phase-separated structure. [Examples]

[0082] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0083] The block copolymers and organic solvents used in the examples and comparative examples are described below.

[0084] [Block copolymer] BCP-1: Represented by the following formula, this is a block copolymer having a block made of polystyrene and a block made of polymethyl methacrylate (Mn 60,000, x:y = 48:52 (mol%)). [ka] BCP-2: Represented by the following formula, this is a block copolymer having a block made of polystyrene and a block made of a random copolymer of 2-hydroxy-3-(ethylsulfanyl)propyl methacrylate and methyl methacrylate (Mn 56,000, x:y:z = 45:3:52 (mol%)). [ka] BCP-3: Represented by the following formula, this is a block copolymer having a block made of polystyrene, a block made of poly(2-hydroxy-3-(ethylsulfanyl)propyl methacrylate), and a block made of polymethyl methacrylate (Mn 56,000, x:y:z = 47:3:50 (mol%)). [ka]

[0085] [organic solvent] (S1)-1: Propylene glycol monomethyl ether acetate (boiling point 146°C) (S2)-1: Ethyl decanoate (boiling point 243°C) [ka] (S2)-2: Dimethyl suberate (boiling point 270°C) [ka] (S2)-3: 1,4-diacetoxybutane (boiling point 230°C) [ka]

[0086] (S3)-1:3-Methoxybutyl acetate (boiling point 172°C) (S3)-2: Gamma-butyrolactone (boiling point 204°C) (S3)-3: Triethylene glycol butyl methyl ether (boiling point 261°C) [ka] (S3)-4: Heptyl enanthate (boiling point: 277°C)

[0087] <Preparation of resin composition for forming phase-separated structures> Each example of a resin composition for forming a phase-separated structure was prepared by mixing and dissolving 100 parts by mass of a block copolymer (BCP) of the type shown in Tables 1-3 with an organic solvent of the type and amount (parts by mass) shown in Tables 1-3.

[0088] <Evaluation of film-forming properties> Each example of a resin composition for forming a phase-separated structure was applied to an 8-inch silicon wafer using a spinner, and baked at 90°C for 1 minute to dry, forming a layer containing a block copolymer (BCP layer) with a thickness of 50 nm. The BCP layer was observed visually and evaluated as A if it was uniformly formed across the entire wafer, and B if unevenness was observed. The results are shown in Tables 1-3 as "Film Formability".

[0089] <Manufacturing of structures including phase-separated structures> After forming a guide pattern with a resist composition, a structure containing a phase-separated structure was obtained using the phase-separated structure-forming resin composition of each example by a manufacturing method comprising the following steps (i) and (ii). In the case where the film-forming performance evaluation was B, uniform film formation could not be achieved, so the manufacturing of the structure containing the phase-separated structure and the evaluation of defects were not performed.

[0090] (Formation of guide patterns) An organic anti-reflective coating composition "ARC-29A" (trade name, manufactured by Brewer Sciences) was applied to a 12-inch silicon wafer substrate using a spinner, and dried by baking on a hot plate at 205°C for 60 seconds to form an organic anti-reflective coating with a thickness of 89 nm. A cross-linked neutral coating composition solution was spin-coated onto the organic anti-reflective coating, and then heated at 250°C for 600 seconds. This formed a 6 nm thin film of the cross-linked neutral coating composition on the substrate surface. A guide pattern formation resist coating composition was applied to the thin film using a spinner, and a 90 nm thick guide pattern formation resist coating was formed by pre-bake (PAB) treatment on a hot plate and drying. The resist coating was selectively irradiated with an ArF excimer laser (193 nm) through a mask pattern using an ArF exposure system "XT-1900Gi" (trade name, manufactured by ASML). Post-exposure heating (PEB) treatment was then performed, followed by development with butyl acetate and complete drying. Next, a post-bake treatment was performed at 100°C for 1 minute, followed by 200°C for 5 minutes, to form a guide pattern that matched a space dimension four times the d value (d spacing determined by small-angle X-ray scattering) of the block copolymer used.

[0091] (Step (i)) After spin-coating each example of the resin composition for forming the phase separation structure onto a substrate with a guide pattern, the mixture was pre-baked at 90°C for 60 seconds under a nitrogen atmosphere to form a layer containing a block copolymer with a thickness of 50 nm (BCP layer).

[0092] (Step (ii)) A BCP layer formed on a substrate was annealed at 200°C for 5 minutes under a nitrogen atmosphere to form a phase-separated structure.

[0093] <Pattern Defect Evaluation> The patterns after process (ii) were observed from above using a measuring SEM (scanning electron microscope, product name: CG6300, Hitachi High-Technologies Corporation) at a magnification of 100,000x, and the number of defects was counted. Based on the results of this count, pattern defects were evaluated according to the evaluation criteria below. The results are shown as "defects" in Tables 1 to 3. (Evaluation Criteria) A: Total number of defects is less than 5 B: Total number of defects is 5 or more but less than 10. C: Total number of defects is 10 or more

[0094] [Table 1]

[0095] [Table 2]

[0096] [Table 3]

[0097] As shown in Tables 1-3, when using the composition of the examples, which includes propylene glycol monomethyl ether acetate (S1) and a solvent (S2) having an ester group and a boiling point of 225°C to 275°C at atmospheric pressure, a uniform film could be formed, and the occurrence of defects in the phase separation film was suppressed when forming a thick phase separation film. On the other hand, when using the comparative example composition, which includes only either propylene glycol monomethyl ether acetate (S1) or the solvent (S2) as the organic solvent (S), the film formation was uneven or the number of defects was high.

Claims

1. A resin composition for forming a phase-separated structure, comprising a block copolymer (A) and an organic solvent (S), A resin composition for forming a phase-separated structure, wherein the organic solvent (S) comprises propylene glycol monomethyl ether acetate (S1) and a solvent (S2) having an ester group and a boiling point of 225°C or higher and 275°C or lower at atmospheric pressure.

2. The resin composition for forming a phase-separated structure according to claim 1, wherein the ratio of the mass of the solvent (S2) to the sum of the mass of the propylene glycol monomethyl ether acetate (S1) and the mass of the solvent (S2) is 5% by mass or more and 60% by mass or less.

3. The resin composition for forming a phase-separated structure according to claim 1, wherein the ratio of the total mass of the propylene glycol monomethyl ether acetate (S1) and the total mass of the solvent (S2) to the total mass of the solvent (S) is 90% by mass or more.

4. The resin composition for forming a phase-separated structure according to claim 1, wherein the solvent (S2) is a compound represented by the following formula (s2-1). R Ｓ１ -X Ｓ１ -R Ｓ２ -X Ｓ２ -R Ｓ３ (s2-1) (In formula (s2-1), R Ｓ１ is a hydrogen atom or an alkyl group which may have a substituent, R Ｓ２ is a single bond or an alkylene group which may have a substituent, R Ｓ３ is an alkyl group which may have a substituent, X Ｓ１ is a single bond or an ester group, X Ｓ２ is an ester group.)

5. The block copolymer (A) comprises at least one selected from the group consisting of block copolymer (A1), block copolymer (A2), and block copolymer (A3), The block copolymer (A1) comprises block (A1-1) and block (A1-2), wherein block (A1-1) is composed of a polymer consisting of a repeating structure of a structural unit represented by the following formula (a1), and block (A1-2) is composed of a polymer consisting of a repeating structure of a structural unit represented by the following formula (a3). The block copolymer (A2) comprises a block (A2-1) and a block (A2-2), wherein the block (A2-1) is composed of a polymer consisting of a repeating structure of a structural unit represented by the following formula (a1), and the block (A2-2) is composed of a random copolymer having a structure in which a structural unit represented by the following formula (a2) and a structural unit represented by the following formula (a3) ​​are randomly arranged. The resin composition for forming a phase-separated structure according to claim 1, wherein the block copolymer (A3) comprises block (A3-1), block (A3-2), and block (A3-3), wherein block (A3-1) is composed of a polymer consisting of a repeating structure of a structural unit represented by the following formula (a1), block (A3-2) is composed of a polymer consisting of a repeating structure of a structural unit represented by the following formula (a2), and block (A3-3) is composed of a polymer consisting of a repeating structure of a structural unit represented by the following formula (a3). 【Chemistry 1】 (In formula (a1), R ａ１ is an alkyl group which may have substituents, and n is an integer between 0 and 5, In formula (a2), R ａ２ R is an alkyl group which may have a silyl group, a fluorine atom, a carboxyl group, an amino group, a hydroxyl group, or a phosphate group. ａ３ This is an alkylene group which may have a hydroxyl group, In formula (a3), R ａ４ is an alkyl group which may have substituents, In formulas (a1) to (a3), R ａ (This is a hydrogen atom or a methyl group.)

6. A layer containing a block copolymer is formed by applying the phase separation structure-forming resin composition according to any one of claims 1 to 5 onto a support, The process involves separating the layer containing the aforementioned block copolymer, A method for manufacturing a structure having a phase-separated structure.

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