Thickening composition, method for manufacturing a thickened resist pattern, and method for manufacturing a processed substrate

Abstract

To provide a thick-film composition. [Solution] The thick-film composition according to the present invention comprises a polymer (A) containing repeating units (A1) represented by formula (a1) and a solvent (B).

Description

[Technical Field]

[0001] This invention relates to a thick-film composition, a method for manufacturing a thick-film resist pattern, and a method for manufacturing a processed substrate. [Background technology]

[0002] In recent years, the need for higher integration in LSIs has increased, requiring miniaturization of resist patterns. To meet these needs, lithography processes using short-wavelength lasers such as KrF excimer lasers, ArF excimer lasers, extreme ultraviolet rays, X-rays, and electron beams are being put into practical use.

[0003] To obtain finer patterns, there is a method (for example, Patent Document 1) in which a resist pattern formed within a range stably obtainable by conventional methods after development is covered with a polymer-containing composition to thicken the resist pattern and refine the hole diameter or separation width. This method is mainly aimed at thickening the width of the resist pattern, and involves developing the resist pattern once and then applying the polymer-containing composition. Furthermore, in response to the demand for thicker resist patterns with higher aspect ratios, compositions containing vinyl resin and amine compounds are also being developed (Patent Document 2). Furthermore, a technique for producing thick-film resist patterns using a solution containing a polymer and a solvent is being investigated (Patent Document 3). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2014-170190 [Patent Document 2] Japanese Patent Publication No. 2017-165846 [Patent Document 3] Japanese Patent Publication No. 2022-096214 [Overview of the Initiative]

Problems to be Solved by the Invention

[0005] The inventors focused on the fact that in EUV lithography, which is expected as a high-definition technology, when used as an etching mask, it may not be able to fulfill the durability as a mask and may be eroded to the object to be masked at the end of the etching process.

[0006] Therefore, the inventors considered that there were one or more problems that still required improvement in the method for manufacturing a resist pattern. These include, for example: thickening a fine resist pattern; obtaining a fine resist pattern useful as an etching mask; suppressing the dissolution of the resist after application of the thickening composition onto the resist; enabling the exposed portion of the thickening layer to be sufficiently dissolved in the developer; obtaining a resist pattern with sufficient etching resistance; obtaining sufficient resolution even when using an exposure machine with an increased numerical aperture; obtaining a fine pattern with suppressed variation in pattern width; obtaining a resist pattern with a high aspect ratio; widening the process window; improving the manufacturing yield.

Means for Solving the Problems

[0007] The thickening composition according to the present invention comprises a polymer (A) containing a repeating unit (A1) represented by the formula (a1) and a solvent (B).

Chemical Formula

[0008] The method for producing a thickened resist pattern according to the present invention comprises the following steps. (1) Applying a resist composition to a substrate to form a resist layer from the resist composition; (2a) Exposing the resist layer; (2b) Applying the above-mentioned thickening composition to the resist layer to form a thickened layer; and (2c) Develop the resist layer and the thickened film layer.

[0009] The method for manufacturing a processed substrate according to the present invention comprises the following steps. Forming the above-mentioned thickened resist pattern; and (3) Processing using a thickened resist pattern as a mask.

[0010] A method for manufacturing the device according to the present invention includes the method described above.

[0011] The present invention relates to the use of a composition comprising a polymer (A) containing repeating units (a1) represented by formula (a1) and a solvent (B) for film formation on a resist layer. The structure of polymer (A) is as described above. [Effects of the Invention]

[0012] According to the present invention, one or more of the following effects can be desired: to make fine resist patterns thicker; to obtain fine resist patterns useful as etching masks; to suppress the dissolution of the resist after the application of the thickening composition to the resist; to allow the exposed areas of the thickening layer to dissolve sufficiently in the developer; to obtain a resist pattern with sufficient etching resistance; to obtain sufficient resolution even when using an exposure machine with an increased numerical aperture; to obtain fine patterns with suppressed pattern width variations; to obtain resist patterns with a high aspect ratio; to widen the process window; and to improve manufacturing yield. [Brief explanation of the drawing]

[0013] [Figure 1] A conceptual diagram illustrating one method for manufacturing thick-film resist patterns. [Modes for carrying out the invention]

[0014] [Definition] In this specification, unless otherwise specified, the definitions and examples set forth in this paragraph shall prevail. The singular form includes the plural form, and "one" or "that" means "at least one." An element of a certain concept can be expressed by multiple types, and when a quantity (e.g., mass %) is given, that quantity represents the sum of those multiple types. "and / or" includes all combinations of elements, as well as their use individually. When a numerical range is indicated using "~" or "-", it includes both endpoints and has the same unit. For example, 5~25 mol% means between 5 mol% and 25 mol%. "C x-y "C x ~C y " and "C x The notation, such as "...", refers to the number of carbon atoms in the molecule or substituent. For example, C 1-6 Alkyl refers to an alkyl chain having between 1 and 6 carbon atoms (such as methyl, ethyl, propyl, butyl, pentyl, and hexyl). When a polymer has multiple types of repeating units, these repeating units copolymerize. These copolymerizations may be alternating copolymerization, random copolymerization, block copolymerization, graft copolymerization, or a mixture of these. When polymers and resins are shown in structural formulas, the n, m, etc., in parentheses indicate the number of repeating units. The unit of temperature used is Celsius. For example, 20 degrees means 20 degrees Celsius. An additive refers to the compound itself that has the function (for example, in the case of a base generator, it is the compound itself that generates a base). The compound may also be added to the composition in the form of being dissolved or dispersed in a solvent. In one embodiment of the present invention, it is preferable that such a solvent is included in the composition according to the present invention as solvent (B) or other component. The term "aryl" refers to a group containing one or more aromatic rings, and includes, but is not limited to, phenyl, anthracenyl, naphthyl, phenantrenyl, fluorenyl, and pyrenyl. Aralkyl refers to alkyl groups substituted with aryl, and includes, but is not limited to, benzyl and phenylethyl.

[0015] The embodiments of the present invention will be described in detail below.

[0016] [Thick-film composition] The thick-film composition according to the present invention comprises a polymer (A) having repeating units (a1) represented by formula (a1) and a solvent (B). The thick-film composition according to the present invention may be applied to the resist layer before development or to the resist layer after development. In a preferred embodiment, the thickening composition according to the present invention is applied to the resist layer before development and not to the resist patterns after development. However, "development" as used here does not include development when patterning a resist layer that has already been removed. For example, in a design where multiple resist patterning steps are performed consecutively, it is possible to use the thickening composition of the present invention to thicken the resist layer in a later step, even if it is after the development of the resist in the previous step.

[0017] (A) Polymer The polymer (A) used in the present invention comprises a repeating unit (A1) represented by formula (a1). One of the features of the thick-film composition according to the present invention is that it contains a polymer (A) comprising repeating units (A1), which is thought to enable the achievement of a thicker film.

[0018] The repeating unit (A1) represented by formula (a1) is as follows: [ka] Here, L 1 , L 2 and L 3 Each of them is independently a single bond, C 1-10 Linear alkylene, C 3-10 Branched-chain alkylenes, or C 3-10 It is a cyclic alkylene (preferably single-bonded or methyl; more preferably single-bonded). R 1 , R 2and R 3 These are H and C, respectively, independently. 1-10 Linear alkyl, C 3-10 Branched-chain alkyl, C 3-10 Cyclic alkyl, C 6-15 Aryl, or C 6-15 It is aralkyl (preferably H or methyl; more preferably H). R 4 C 1-15 Linear alkyl, C 3-15 Branched-chain alkyl, C 3-15 Cyclic alkyl, C 6-15 Ariel, C 6-15 Aralquil, or any combination thereof. Here, R 4 One or more hydrogen atoms inside are C 1-5 It may be replaced by a linear alkyl group, -COOH, or -OH. Here, R 4 C 1-15 It is a linear alkyl group, and one or more hydrogen atoms of the linear alkyl group are C 1-5 When replaced with a linear alkyl group, R 4 It may also be a branched alkyl group. L 1 , L 2 , L 3 , R 1 , R 2 , R 3 and R 4 Among them, one or more non-adjacent methylene (-CH2-) groups are -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -CR 5 =CR 6 - or -C≡C- may be used as substitutes, but it is preferable that they are not used. R 5 and R 6 These are, independently, H or C 1-6 It is a linear alkyl group, preferably hydrogen or methyl. X is either O or S, and is preferably O. n is 0 or 1, preferably 1.

[0019] Specific examples of the compounds that can be read by formula (a1) will be described in detail below. The following compounds can be read by formula (a1). L 1 、L 2 and L 3 are single bonds, R 1 、R 2 and R 3 are H, X is O, R 4 is a C 10 cyclic alkyl (adamantyl) in which one hydrogen atom is replaced by a C2 straight-chain alkyl (ethyl), and n is 1.

Chemical formula

[0020] The following compounds can also be read by formula (a1). L 1 、L 2 and L 3 are single bonds, R 1 、R 2 and R 3 are H, X is O, R 4 is a combination of a C1 straight-chain alkyl, a C6 cyclic alkyl, and a C1 straight-chain alkyl in which one hydrogen atom is replaced by -OH, and n is 1. As shown in this example, when R 4 is a combination of multiple substituents, a monovalent substituent can be regarded as a divalent substituent with one hydrogen atom removed and combined with other substituents.

Chemical formula

[0021] R 4 may be represented by formula (a2). -(R 7 ) p -(R 8 ) q -R 9 (a2) Here, R 7 is a C 1-15 straight-chain alkylene, a C 3-15 branched-chain alkylene, a C 3-15It is a cyclic alkylene or phenylene, R 8 C 1-15 Linear alkylene, C 3-15 Branched-chain alkylene, C 3-15 It is a cyclic alkylene or phenylene, R 9 C 1-15 Linear alkyl, C 3-15 Branched-chain alkyl, C 3-15 It is a cyclic alkyl, phenyl, or benzyl, Here, R 7 , R 8 , or R 9 One or more hydrogens in any of the C 1-5 It may be replaced by a linear alkyl group, -COOH, or -OH. p and q are independently either 0 or 1. Here, R 7 , R 8 , or R 9 C 1-15 It is a linear alkyl group, and one or more hydrogen atoms of the linear alkyl group are C 1-5 When replaced with a linear alkyl group, R 7 , R 8 , or R 9 It may also be a branched alkyl group.

[0022] One preferred form is when p and q are 0, and R 9 C 1-15 Linear alkyl, C 3-15 Branched-chain alkyl, C 3-15 It is a cyclic alkyl, phenyl, or benzyl, and R 9 One or more hydrogen atoms are C 1-5 It may be replaced by a linear alkyl, -COOH, or -OH. More preferably, p and q are 0, and R 9 C 1-10 Linear alkyl, C 3-10 Branched-chain alkyl, C 3-10 It is a cyclic alkyl, phenyl, or benzyl, and R 9 One or more hydrogen atoms are C 1-5It may be replaced by a linear alkyl, -COOH, or -OH. More preferably, p and q are 0, and R 9 C 1-8 Linear alkyl, C 3-8 Branched-chain alkyl, C 3-10 It is a cyclic alkyl, phenyl, or benzyl, and R 9 One or more hydrogen atoms may be replaced by -OH groups. One preferred form is when p and q are 1, and R 7 C 1-10 Linear alkylene, R 8 C 3-10 Cyclic alkylene, R 9 C 3-10 It is a linear alkyl group, R 9 One or more hydrogen atoms may be replaced by -OH groups.

[0023] R 4 Examples include n-propyl, n-butyl, isopropyl, isobutyl, cycloalkyl, 2-ethylhexyl, hydroxyethyl, hydroxypropyl, hydroxybutyl, 4-(hydroxymethyl)cyclohexylmethyl, adamantyl, benzyl, phenyl, and 4-hydroxyphenyl.

[0024] Examples of repeating units (A1) include the following: [ka]

[0025] For the repeating unit (A1), the carbon atom parameter represented by formula (I) is preferably 2.0 to 5.0, more preferably 2.0 to 4.0, and even more preferably 2.0 to 3.5. Carbon atom parameter = (Total number of atoms in repeating unit (A1)) / (Number of C atoms in repeating unit (A1) - Number of O atoms in repeating unit (A1)) (I) For the polymer (A) as a whole, formula (I)' is preferably 2.0 to 5.0, more preferably 2.0 to 4.0, and even more preferably 2.0 to 3.5. Carbon atom parameter = (Total number of atoms in polymer (A)) / (Number of C atoms in polymer (A) - Number of O atoms in polymer (A)) (I)'

[0026] For the repeating unit (A1), the cyclic structure ratio represented by formula (II) is preferably 5 to 80%, and more preferably 20 to 80%, in order to achieve a thicker film. Cyclic structure ratio = (Sum of atomic weights of all atoms constituting the cyclic structure in the repeating unit (A1)) / (Sum of atomic weights of all atoms constituting the repeating unit (A1)) × 100 (II) For the polymer (A) as a whole, formula (II)' is preferably present in 5-80%, and more preferably in 20-80%. Cyclic structure ratio = (Sum of atomic weights of all atoms constituting the cyclic structure in polymer (A)) / (Sum of atomic weights of all atoms constituting polymer (A)) × 100 (II)'

[0027] The polymer (A) may contain repeating units other than repeating units (A1) as long as it does not impair the scope of the present invention. The proportion of repeating units (A1) is preferably 60-100%, more preferably 80-100%, and even more preferably 95-100%, based on the total number of repeating units constituting the polymer (A). In a more preferred embodiment, the polymer (A) is substantially composed of repeating units (A1), more preferably of repeating units (A1).

[0028] In the molecular weight distribution curve of polymer (A) obtained by gel permeation chromatography (GPC), the ratio of the amount with a polystyrene-equivalent molecular weight of 500 to 10,000 to the total amount of polymer (A) (hereinafter sometimes referred to as "molecular weight ratio of 500 to 10,000") is preferably 60% or more, more preferably 70 to 100%, and even more preferably 80 to 100%.

[0029] The molecular weight ratio of 500 to 10,000 can be determined as follows. First, in the molecular weight distribution curve of the thick film composition obtained by GPC, the peak with the largest area ratio among the peaks in the molecular weight distribution curve is identified as the peak of polymer (A). For the identified polymer (A), the area under the peaks in the molecular weight distribution curve (representing molecular weight on a logarithmic scale) in the range of 500 to 10,000 can be determined. Dividing this area by the total area of ​​the peaks for polymer (A) and multiplying by 100 gives the ratio of the amount of polymer (A) with a polystyrene-equivalent molecular weight of 500 to 10,000.

[0030] The mass-average molecular weight of polymer (A) is preferably 500 to 20,000, more preferably 500 to 8,000, even more preferably 800 to 5,000, and even more preferably 1,000 to 3,000. In this invention, mass-average molecular weight (Mw) refers to the polystyrene-represented average mass molecular weight measured using GPC.

[0031] Although not bound by theory, it is thought that the effects of the present invention are better realized when the carbon atom parameter of polymer (A) in the repeating unit (A1) is 5.0 or less, the cyclic structure ratio is 5% or more, the molecular weight ratio of 500 to 10,000 is 60% or more, or the mass average molecular weight is 500 or more, and the following points can be inferred. First, when a thickening composition is applied to the resist layer and a thickened layer is formed by heating or other means, it is thought that the polymers of the thickened layer and the resist layer penetrate each other (intermixing) at the point of contact, forming a mixed layer. It is thought that the resist pattern can be made thicker by the formation of this mixed layer. Furthermore, since the amount of the thickening composition that penetrates the resist layer is reduced after applying the thickening composition to the resist layer, it is thought that the dissolution of the resist can be sufficiently suppressed. Furthermore, it is believed that a thick film layer with sufficient etching resistance can be formed.

[0032] Although not bound by theory, it is thought that the solubility of the exposed portion of the thick film layer in the developer can be further improved if the carbon atom parameter of polymer (A) in the repeating unit (A1) is 2.0 or higher, the cyclic structure ratio is 80% or lower, or the mass-average molecular weight is 10,000 or lower. Furthermore, it is thought that the solubility of polymer (A) in solvent (B) can be further improved.

[0033] The polymer (A) content is preferably 0.01 to 30% by mass, more preferably 0.5 to 20% by mass, and even more preferably 1 to 10% by mass, based on the total mass of the thick film composition. The thick-film composition contains polymer (A), but may also contain polymers other than polymer (A). The content of polymers other than polymer (A) is preferably 0 to 20% by mass, more preferably 0 to 10% by mass, even more preferably 0 to 5% by mass, and even more preferably 0% by mass (not included) based on the total mass of the thick-film composition.

[0034] (B) Solvent Solvent (B) is for dissolving polymer (A) and other components as needed.

[0035] The solvent (B) preferably comprises a solvent (B1) represented by formula (b1). R 21 -O―R 22 (b1) Here, R 21 and R 22 Each of them is independent of C 1-8 It is alkyl. Preferably C 3-6They are alkyl groups. More preferably methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, n-pentyl, isopentyl, cyclopentyl, or cyclohexyl. Even more preferably methyl, n-butyl, n-pentyl, isopropyl, cyclopentyl, or cyclohexyl. Even more preferably n-butyl. These are linear, branched, or cyclic, preferably linear or cyclic, and more preferably linear. R 21 and R 22 They may be different or the same, but preferably they are the same.

[0036] Examples of solvents (B1) include dibutyl ether, dipentyl ether, diisopentyl ether, dicyclopentyl ether, disicyclohexyl ether, and cyclopentyl methyl ether. In one preferred embodiment, solvent (B) preferably consists substantially of solvent (B1) and more preferably consists solely of solvent (B1).

[0037] In another preferred embodiment, solvent (B) preferably comprises a solvent (B2) different from solvent (B1), and more preferably consists only of solvent (B1) and solvent (B2). Preferably, the solvent (B2) is cyclohexanone, cyclopentanone, propylene glycol monomethyl ether (PGME), propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, γ-butyrolactone, ethyl lactate, 2-propanol (IPA), or any combination thereof. The solvent (B2) is preferably PGME, PGMEA, or a combination thereof. If there are two types of solvents in solvent (B2), their mass ratio is preferably 100:1 to 1:100, more preferably 50:1 to 1:50, and even more preferably 30:1 to 1:30. The solvent (B2) may contain water. The water content is preferably 5% by mass or less, more preferably 1% by mass or less, and even more preferably 0.001% by mass or less, based on the solvent (B). It is also a preferred embodiment of the present invention that the solvent (B2) does not contain water (0.000% by mass). Although not bound by theory, it is believed that the solvent (B) of the composition according to the present invention can contribute to the formation of a thick film pattern by dissolving the solid components (components other than solvent (B)) while avoiding dissolving the underlying resist film.

[0038] The content of solvent (B) is preferably 70 to 99.99% by mass, more preferably 80 to 99.99% by mass, even more preferably 95 to 99.99% by mass, and even more preferably 95 to 99.90% by mass, based on the composition according to the present invention. The content of solvent (B1) is preferably 70 to 100% by mass, more preferably 80 to 100% by mass, and even more preferably 90 to 100% by mass, based on solvent (B). The content of solvent (B2) is preferably 0 to 30% by mass, more preferably 0 to 20% by mass, and even more preferably 0.1 to 10% by mass, based on solvent (B).

[0039] (C) Surfactants The thick-film composition according to the present invention may further contain a surfactant (C). Including surfactant (C) can improve the applicability. Examples of surfactants that can be used in the present invention include (I) anionic surfactants, (II) cationic surfactants, or (III) nonionic surfactants, more specifically (I) alkyl sulfonates, alkylbenzene sulfonic acid, and alkylbenzene sulfonates, (II) laurylpyridinium chloride and laurylmethylammonium chloride, and (III) polyoxyethylene octyl ether, polyoxyethylene lauryl ether, polyoxyethylene acetylene glycol ether, fluorine-containing surfactants (e.g., Florard (3M), MEGAFACE (DIC), Sulfuron (Asahi Glass), and organosiloxane surfactants (e.g., KF-53, KP341 (Shin-Etsu Chemical Co., Ltd.)). These surfactants can be used individually or in combination of two or more.

[0040] The content of surfactant (C) is preferably 0 to 5% by mass; more preferably 0.001 to 2% by mass; and even more preferably 0.01 to 1% by mass, based on the total mass of the thick-film composition. The absence of surfactant (C) (0% by mass) is also an embodiment of the present invention.

[0041] (D) Additives The thick-film composition according to the present invention may further contain an additive (D) other than the components (A) to (C) described above. The additive (D) is preferably a plasticizer, a crosslinking agent, an antibacterial agent, a bactericide, a preservative, an antifungal agent, an acid, a base, an organic salt, or a mixture of at least one of these.

[0042] The content of additive (D) is preferably 0 to 10% by mass; more preferably 0.001 to 5% by mass; even more preferably 0.01 to 4% by mass; and even more preferably 0.1 to 3% by mass, based on the total mass of the thick-film composition. A preferred embodiment of the present invention is that the thick-film composition according to the present invention does not contain additive (D) (0% by mass).

[0043] <Method for manufacturing thickened resist patterns> The method for producing a thickened resist pattern according to the present invention comprises the following steps. (1) Applying a resist composition to a substrate to form a resist layer from the resist composition; (2a) Exposing the resist layer; (2b) Applying the thick-film composition according to the present invention to the resist layer to form a thick-film layer; and (2c) Develop the resist layer and the thickened film layer. The following steps will be explained using diagrams. For clarity, steps (1), (2a), (2b), and (2c) are performed before step (3). The numbers in parentheses indicating the steps indicate their order. However, the order of steps (2a), (2b), and (2c) is arbitrary. The same applies hereafter.

[0044] Step (1) In step (1), the resist composition is applied to the substrate to form a resist layer. Examples of substrates include silicon / silicon dioxide coated substrates, silicon nitride substrates, silicon wafer substrates, glass substrates, and ITO substrates. The resist composition is not particularly limited, but from the viewpoint of forming a fine, high-resolution resist pattern, it is preferably a chemically amplified resist composition, for example, a chemically amplified PHS-acrylate hybrid EUV resist composition. It is also preferable that the resist composition contains a photoacid generator. A preferred resist composition of the present invention is a positive-type chemically amplified resist composition. The resist composition of the present invention can also use a negative-type resist composition. Known negative-type resist compositions and processes can be used.

[0045] The resist composition is applied to the substrate by an appropriate method. Here, in this invention, "on top of the substrate" includes application directly on the substrate and application via other layers. For example, a resist underlayer (e.g., SOC (Spin On Carbon) and / or adhesion-enhancing film) may be formed directly on the substrate, and the resist composition may be applied directly on top of it. Preferably, the resist composition is applied directly on the substrate. In another preferred embodiment, an SOC is formed directly on the substrate, an adhesion-enhancing film is formed directly on top of the SOC, and the resist composition is applied directly on top of them. The application method is not particularly limited, but one example is coating by spin coating. A substrate to which a resist composition has been applied is preferably heated to form a resist layer. This heating is also called pre-baking and is performed, for example, by a hot plate. The heating temperature is preferably 100 to 250°C; more preferably 100 to 200°C; even more preferably 100 to 160°C. Here, the temperature is the heating surface temperature of the hot plate. The heating time is preferably 30 to 300 seconds; more preferably 30 to 120 seconds; even more preferably 45 to 90 seconds. The heating is preferably performed in an atmosphere of air or nitrogen gas; more preferably in an atmosphere of air. Figure 1(i) is a schematic diagram showing a resist layer 2 formed on a substrate 1. The thickness of the resist layer is selected according to the purpose, but is preferably 10 to 100 nm; more preferably 10 to 40 nm; and even more preferably 10 to 30 nm.

[0046] Step (2a) In step (2a), the resist layer is exposed, optionally through a mask. The wavelength of the radiation (light) used for exposure is not particularly limited, but exposure with light having a wavelength of 13.5 to 248 nm is preferred. Specifically, KrF excimer lasers (wavelength 248 nm), ArF excimer lasers (wavelength 193 nm), and EUV (extreme ultraviolet, wavelength 13.5 nm) can be used. EUV light is more preferred. A range of ±1% in these wavelengths is acceptable. After exposure, post-exposure heating (PEB) can be performed as needed. The PEB temperature can be selected from a range of 70 to 150°C, preferably 80 to 120°C. The PEB heating time can be selected from a range of 0.3 to 5 minutes, preferably 0.5 to 2 minutes. Figure 1(ii) is a schematic diagram showing the state of the resist layer 2 in a case using a typical positive-type chemically amplified resist composition after exposure through a mask. Acid is released from the photoacid generator in the exposed area 4, which deprotects the polymer and increases its alkali solubility. The alkali solubility of the polymer in the unexposed area 3 remains unchanged.

[0047] Step (2b) In step (2b), a thick-film composition comprising polymer (A) and solvent (B) is applied to the resist layer to form a thick-film layer. The application method is not particularly limited, but one example is coating by spin coating. A substrate to which a thick-film composition has been applied is preferably heated or spin-dried (more preferably by heating) to form a thick-film layer. Heating is performed, for example, using a hot plate. The heating temperature is preferably 45 to 150°C; more preferably 60 to 130°C. The heating time is preferably 30 to 180 seconds; more preferably 45 to 90 seconds. Heating is preferably carried out in an atmosphere of air or nitrogen gas; more preferably in an atmosphere of air. The heating in (2b) is also called a mixing bake. Figure 1(iii) is a schematic diagram showing a state in which a thickened film layer 5 is formed on the resist layer 2.

[0048] In step (2b), preferably, an insolubilized layer is formed in the vicinity of the contact area between the thickened film layer and the resist layer. Although not bound by theory, it is thought that in the area where the thickened film layer and the resist layer are in contact, the polymers of each layer penetrate each other (intermixing), forming a mixed layer. Whether the mixed layer is soluble or insoluble in the developer in the subsequent developing step depends on whether the underlying resist layer is soluble or insoluble in the developer. If the area of ​​the underlying resist layer is insoluble in the developer, the mixed layer becomes an insolubilized layer. If the area of ​​the underlying resist layer is soluble in the developer, the mixed layer also becomes soluble. Let's explain using the example of a positive-type resist layer. Since the exposed portion of the resist layer is soluble in the developer, the resist layer (matrix component, preferably polymer) that has penetrated the mixed layer in that region dissolves, and the mixed layer also dissolves. The exposed portion of the resist layer below the mixed layer also dissolves. On the other hand, the unexposed portion of the resist layer is insoluble in the developer (for example, it is not deprotected). Therefore, the resist layer that has penetrated the mixed layer in that region is insoluble, and the mixed layer does not dissolve. The unexposed portion of the resist layer below the mixed layer also does not dissolve. Figure 1(iv) is a schematic diagram showing the state in which the insolubilized layer 6 is formed. A mixed layer is also formed in the dissolving region (the exposed area in positive type), but it is not shown in (iv) for simplicity because it is dissolved and removed during the development process.

[0049] In step (2b), it is also preferable to rinse after forming the thickened layer to remove the upper part of the thickened layer (the thickened layer above the mixed layer). The rinse can be one which has the same composition as the solvent (B) of the thickened composition. The rinsing in this invention is different from the developing described later. That is, the rinsing is not for dissolving the soluble regions of the resist layer to form a resist pattern.

[0050] Step (2c) In step (2c), the resist layer, or the resist layer and the thickened layer, are developed. Methods for applying the developer include, for example, the paddle method, the dip method, and the spray method. The developer temperature is preferably 5 to 50°C; more preferably 25 to 40°C, and the development time is preferably 15 to 120 seconds; more preferably 30 to 60 seconds. After application of the developer, it is removed. The resist pattern after development can also be rinsed. Rinsing can preferably be done with water (DIW). The developing solution is preferably an alkaline aqueous solution or an organic solvent; more preferably an alkaline aqueous solution. Examples of alkaline aqueous solutions include aqueous solutions containing inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, and sodium silicate; organic amines such as ammonia, ethylamine, propylamine, diethylamine, diethylaminoethanol, and triethylamine; and quaternary amines such as tetramethylammonium hydroxide (TMAH); more preferably an aqueous TMAH solution; and even more preferably a 2.38% by mass TMAH aqueous solution. The developer can also be further enriched by adding the surfactants mentioned above.

[0051] The order of (2a), (2b), and (2c) is arbitrary. The process of performing (2b) after (2a) is more preferable because it is not necessary to expose while transmitting through the thickened film layer. The process of performing (2a) after (2b) is also possible, in which case it is preferable to perform exposure while controlling the effect of transmitting through the thickened film layer. Since the development process only needs to be done once, it is preferable to perform (2c) after (2a) and (2b). In a preferred embodiment of the present invention, the steps are performed in the order of (2a), (2b), and (2c).

[0052] Figure 1(v) shows the state in which the developer solution has been applied to the resist layer and the thickened layer, the developer solution has been removed, and the thickened resist pattern 7 has been formed. If the amount of thickening is defined as (height of the thickened resist pattern) - (height of a resist pattern formed similarly except that the thickening composition is not applied), then the amount of thickening is preferably 2 to 20 nm; more preferably 2 to 15 nm; even more preferably 5 to 10 nm; and even more preferably 5.5 to 8 nm. Although not bound by theory, in high-resolution lithography techniques such as EUV exposure, the thickness of the resist film is generally thin. However, by thickening the film according to the present invention, it is considered possible to ensure durability as a mask when used in a later process, for example, as an etching mask.

[0053] <Manufacturing methods for processed substrates and devices> The method for manufacturing a processed substrate according to the present invention comprises the following steps. Forming the thickened resist pattern described above; and (3) Processing using a thickened resist pattern as a mask.

[0054] Step (3) In step (3), the processing is carried out using the thickened resist pattern as a mask. The thickened resist pattern is preferably used for processing the resist underlayer or substrate (more preferably the substrate). Specifically, the resist pattern can be used as a mask to process various substrates using methods such as dry etching, wet etching, ion implantation, and metal plating. Because the resist pattern is thickened, it can function as a mask even under more stringent conditions, making it suitable for processing by dry etching. When processing the resist underlayer using a thickened resist pattern, the processing may be carried out in steps. For example, the resist pattern may be used to process the adhesion-enhancing film and the SOC, and the SOC pattern may be used to process the substrate. For example, SiARC (Si anti-reflective coating) can be used as the adhesion-enhancing film.

[0055] A method for manufacturing a device according to the present invention comprises the above-described method and further comprises the step of forming wiring on an optionally processed substrate. Known methods can be applied to these processing steps. Subsequently, the substrate is cut into chips as needed, connected to a lead frame, and packaged with resin. In the present invention, this packaged product is referred to as a device. Examples of devices include semiconductor devices, liquid crystal display elements, organic EL display elements, plasma display elements, and solar cell elements, and semiconductor devices are preferred.

[0056] The present invention relates to the use of a composition comprising a polymer (A) containing repeating units (A1) represented by formula (a1) and a solvent (B) for film formation on a resist layer. Preferred forms of the polymer (A) and solvent (B) are as described above. The composition comprising the polymer (A) and solvent (B) is preferably a thick-film composition, and preferred forms are as described above. [Examples]

[0057] The present invention will be described below with reference to various examples. However, the embodiments of the present invention are not limited to these examples.

[0058] [Synthesis of polymer (A)] (1) Synthesis of poly(cyclohexyl vinyl ether) A 100 mL three-necked flask is dried for 10 minutes using a heat gun under a nitrogen atmosphere. Then, n-butylammonium bromide and dichloromethane are added to the three-necked flask to prepare 32 mL of a 5.25 mmol / L solution. Next, 4 mL of a 40 mmol / L trifluoromethanesulfonic acid dichloromethane solution is added to the three-necked flask using a dry syringe. This solution is brought to -40°C, 4 mL of cyclohexyl vinyl ether is added, and the mixture is reacted for 27 hours. Then, a mixture of 5 mL of 0.1% by mass aqueous ammonia and 5 mL of ethanol is added to stop the reaction. The mixture is washed three times with 30 mL of water, 10 g of magnesium sulfate is added and the mixture is stirred for 5 minutes, and the solid is filtered to remove the solvent from the resulting mixture under reduced pressure. Then, the mixture is dried under reduced pressure using a vacuum at room temperature for more than 3 hours to obtain poly(cyclohexyl vinyl ether) (Mw: 1800, PDI (Poly Dispersity Index) = 1.9) in a yield of 82%. (2) Synthesis of poly(isobutyl vinyl ether) The synthesis is carried out using the same method as in synthesis (1), except that cyclohexyl vinyl ether is replaced with isobutyl vinyl ether. The resulting poly(isobutyl vinyl ether) has a Mw of 1960, a PDI of 2.1, and a yield of 76%. (3) Synthesis of poly(isopropyl vinyl ether) The synthesis is carried out using the same method as in synthesis (1), except that cyclohexyl vinyl ether is replaced with isopropyl vinyl ether. The resulting poly(isopropyl vinyl ether) has a Mw of 2040, a PDI of 2.0, and a yield of 73%.

[0059] [Preparation of compositions for Examples 1-3 and Reference Example 1] The polymer (A) listed in Table 1 is dissolved in the solvent (B), which is dibutyl ether. The content of polymer (A) is 1.0% by mass relative to the total mass of the composition. The resulting solution is stirred at room temperature for 60 minutes. After visually confirming that the solute is completely dissolved, the solution is filtered through a 0.2 μm fluorine resin filter to obtain the compositions of Examples 1 to 3. In Reference Example 1, instead of polymer (A), a monomer, cyclohexyl vinyl ether (molecular weight 126.2, carbon atom parameter 3.3), is used, and the composition of Reference Example 1 is obtained by preparing it in the same manner as above. [Table 1] In the table, P1: Poly(cyclohexyl vinyl ether), Mw 1,800, carbon atom parameter 3.3, cyclic structure ratio 65%, [ka] P2: Poly(isobutyl vinyl ether), Mw 1,960, carbon atom parameter 3.8, [ka] • P3: Poly(isopropyl vinyl ether), Mw 2,040, carbon atom parameter 4.0, [ka] M1: Cyclohexyl vinyl ether, molecular weight 126.2, carbon atom parameter 3.3.

[0060] [Measurement of mass-average molecular weight (Mw)] The mass-average molecular weight (Mw) of the compositions of Examples 1-3 and Reference Example 1 was measured by gel permeation chromatography (detector: differential refractometer) using monodisperse polystyrene as the standard, under analytical conditions of a flow rate of 1.0 ml / min, elution solvent tetrahydrofuran (Kishida Chemical), and column temperature of 40°C, using GPC columns (two "G2000HXL" and one "G3000HXL" from Tosoh Corporation). The sample to be analyzed was prepared by dissolving the polymer in tetrahydrofuran to make a 0.5 wt% solution, filtering it through a 0.2 μm pore size PTFE filter, and then analyzing it.

[0061] [Calculation of molecular weight ratios between 500 and 10,000] The compositions of Examples 1-3 and Reference Example 1 were measured by gel permeation chromatography in the same manner as described above to obtain molecular weight distribution curves. The peak with the largest area percentage among the peaks in the molecular weight distribution curve was defined as the peak of polymer (A). For polymer (A), determine the area under the peaks in the molecular weight distribution curve (representing molecular weight on a logarithmic scale) in the range of 500 to 10,000. Divide this area by the total area of ​​polymer (A) peaks and multiply by 100 to determine the ratio of polymer (A) whose polystyrene-equivalent molecular weight is between 500 and 10,000. The obtained results are shown in Table 1.

[0062] [Evaluation of film thickness variation] A silicon substrate is treated with HMDS (hexamethyldisilazane) at 90°C for 30 seconds. An EUV chemically amplified PHS-acrylate hybrid resist composition (positive type) is applied to the HMDS-treated substrate by spin coating and heated on a hot plate at 110°C for 60 seconds to form a resist layer with a thickness of 35 nm. The composition from Example 1 is poured onto the resist layer, covering the resist layer with the composition from Example 1, and left to stand for 60 seconds. The substrate is then rotated at high speed to dry. The film thickness at this time is measured using an ellipsometer M-2000 (JAWoollam). The amount of film thickening is obtained by subtracting the film thickness of the resist layer (35 nm) from the film thickness at this time, and the obtained results are shown in Table 1. Film thickness variation is evaluated according to the following criteria, and the results obtained are listed in Table 1. A:5.0nm<thickening amount≦10.0nm B: Thickening amount ≦5.0nm The compositions of Examples 2 and 3 and Reference Example 1 are evaluated in the same manner.

[0063] [LWR rating] A silicon substrate is subjected to HMDS treatment at 90°C for 30 seconds. A chemically amplified PHS-acrylate hybrid resist composition (positive type) for EUV is applied to the HMDS-treated substrate by spin coating and heated on a hot plate at 110°C for 60 seconds to form a resist layer with a thickness of 35 nm. The resist layer is exposed using an EUV lithography apparatus (NXE:3300B, ASML) through an 18 nm (line:space = 1:1) mask while varying the exposure amount. After that, post-exposure heating (PEB) is performed at 100°C for 60 seconds. Then, the composition from Example 1 is applied on top of the resist layer by spin coating and heated at 90°C for 60 seconds to form a thick film layer. Then, paddle development is performed for 30 seconds using a 2.38 mass% TMAH aqueous solution as the developer. Water is then dropped while the developer is paddled on the substrate, and the water is continued while rotating the substrate to replace the developer with water. Subsequently, the substrate is rotated at high speed to dry the thickened resist pattern of Example 1. The obtained thickened resist pattern is observed using a SEM device CG6300 (Hitachi High-Technologies), and the line width and LWR (Line Width Roughness) value are measured. ((LWR value / line width) × 100) is calculated, and this value is designated as X. The results are evaluated according to the following criteria and recorded in Table 1. A:X≦20 B:X>20 The compositions of Examples 2 and 3 and Reference Example 1 are evaluated in the same manner.

[0064] [Evaluation of etching resistance] A silicon substrate is subjected to HMDS treatment at 90°C for 30 seconds. A chemically amplified PHS-acrylate hybrid resist composition (positive type) for EUV is applied to the HMDS-treated substrate by spin coating and heated on a hot plate at 110°C for 60 seconds to form a resist layer with a thickness of 35 nm. The composition from Example 1 is applied on top of the resist layer by spin coating and heated at 90°C for 60 seconds to form a thick film layer. The resulting substrate is placed in a dry etching apparatus and subjected to CF 4(Plasma etching is performed for 15 seconds at a substrate temperature of 23°C using a mixed gas of 5 mL / min (O2), 10 mL / min (O2), and 500 mL / min (Ar). Afterward, the amount of residual resist film is measured using an ellipsometer M-2000 (JAWoollam). This residual film amount is denoted as Y1. A larger residual film amount indicates better plasma etching resistance. For comparison, a resist layer with a thickness of 35 nm was also etched in the same manner as described above, and the amount of remaining film was measured. This amount of remaining film was denoted as Y2. Calculate Y = Y1 / Y2 × 100, evaluate it according to the following criteria, and record the results in Table 1. A:110 <Y B:100 <Y≦110 The compositions of Examples 2 and 3 and Reference Example 1 are evaluated in the same manner. [Explanation of symbols]

[0065] 1. Circuit board 2. Resist layer 3. Unexposed areas 4. Exposure area 5.Thickened layer 6. Immobilization layer 7. Thickened resist pattern 8. Height of the thickened resist pattern

Claims

1. A thick-film composition comprising a polymer (A) containing repeating units (A1) represented by formula (a1) and a solvent (B): 【Chemistry 1】 (Here, L １ , L ２ and L ３ Each of them is independently a single bond, C １－１０ Linear alkylene, C 3－１０ Branched-chain alkylenes, or C 3－１０ It is a cyclic alkylene; R １ 、 R ２ and R ３ are each independently H, C １－１０ linear alkyl, C ３－１０ branched alkyl, C ３－１０ cyclic alkyl, C ６－１５ aryl or C ６－１５ aralkyl; R ４ C １－１５ Linear alkyl, C ３－１５ Branched-chain alkyl, C ３－１５ Cyclic alkyl, C ６－１５ Ariel, C ６－１５ Aralkill, or any combination thereof; Here, R ４ One or more hydrogen atoms in the middle are C １－５ It may be replaced by a linear alkyl group, -COOH, or -OH; Here, L １ , L ２ , L ３ , R １ , R ２ , R ３ and R ４ One or more non-adjacent methylene (-CH) ２ -) is -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -CR ５ =CR ６ It may also be replaced by - or -C≡C-; R ５ and R ６ These are, independently, H or C １－６ It is a linear alkyl group; X is either O or S; n is either 0 or 1.

2. R ４ The thick-film composition according to claim 1, which is represented by formula (a2). -(R ７ ) ｐ -(R ８ ) ｑ -R ９ (a2) (Here, R ７ C １－１５ Linear alkylene, C ３－１５ Branched-chain alkylene, C ３－１５ It is a cyclic alkylene or phenylene, R ８ C １－１５ Linear alkylene, C ３－１５ Branched-chain alkylene, C ３－１５ It is a cyclic alkylene or phenylene, R ９ C １－１５ Linear alkyl, C ３－１５ Branched-chain alkyl, C ３－１５ It is a cyclic alkyl, phenyl, or benzyl, Here, R ７ , R ８ , or R ９ One or more hydrogen atoms in any of the C １－５ It may be replaced by a linear alkyl group, -COOH, or -OH. p and q are either 0 or 1, independently of each other.

3. The thick-film composition according to claim 1 or 2, wherein the mass-average molecular weight of polymer (A) is 500 to 20,000.

4. The thick-film composition according to any one of claims 1 to 3, wherein, in the molecular weight distribution curve of polymer (A) obtained by gel permeation chromatography, the amount of polymer (A) with a polystyrene-equivalent molecular weight of 500 to 10,000 is 60% or more of the total amount of polymer (A).

5. The thick-film composition according to any one of claims 1 to 4, wherein the carbon atom parameter represented by formula (I) is 2.0 to 5.

0. Carbon atom parameter = (Total number of atoms in repeating unit (A1)) / (Number of C atoms in repeating unit (A1) - Number of O atoms in repeating unit (A1)) (I)

6. The thick-film composition according to any one of claims 1 to 5, wherein the proportion of the cyclic structure represented by formula (II) is 5 to 80%. Cyclic structure ratio = (Sum of atomic weights of all atoms constituting the cyclic structure in the repeating unit (A1)) / (Sum of atomic weights of all atoms constituting the repeating unit (A1)) × 100 (II)

7. L １ , L ２ and L ３ A thick-film composition according to any one of claims 1 to 6, wherein the bond is a single bond.

8. R １ , R ２ and R ３ A thick-film composition according to any one of claims 1 to 7, wherein is H.

9. The thick-film composition according to any one of claims 1 to 8, wherein the content of polymer (A) is 0.01 to 30% by mass, based on the total mass of the thick-film composition.

10. The solvent (B) contains the solvent (B1) represented by formula (b1), Optionally, the content of solvent (B) is 70 to 99.99% by mass based on the thick film composition, or The thick-film composition according to any one of claims 1 to 9, wherein the content of solvent (B1) is optionally 70 to 100% by mass based on solvent (B). R ２１ -O―R ２２ (A1) (Here, R ２１ and R ２２ Each is independently a linear, branched, or cyclic C １－８ (It is alkyl.)

11. A method for manufacturing a thickened resist pattern comprising the following steps: (1) Applying a resist composition to a substrate and forming a resist layer from the resist composition (preferably by heating); (2a) Exposing the resist layer (preferably with EUV light); (2b) Applying the thickening composition according to any one of claims 1 to 10 to the resist layer to form a thickening layer (preferably by heating or spin-drying); and (2c) Develop the resist layer and the thickened film layer (preferably with an alkaline aqueous solution or an organic solvent; more preferably with an alkaline aqueous solution).

12. The method according to claim 11, further comprising rinsing after forming a thickened film layer in step (2b) to remove the upper part of the thickened film layer.

13. The method according to claim 11 or 12, wherein the resist composition is a chemically amplified resist composition.

14. The method according to any one of claims 11 to 13, wherein the resist composition further comprises a photoacid generator.

15. A method for manufacturing a processed substrate comprising the following steps: To form a thickened resist pattern according to at least one of claims 11 to 14; and (3) Processing using the thickened resist pattern as a mask.

16. A method for manufacturing a device comprising the method of claim 15: Optionally, further comprising the step of forming wiring on a processed substrate; or The device is, arbitrarily, a semiconductor device.

17. Use of a composition comprising a polymer (A) containing repeating units (a1) represented by formula (a1) and a solvent (B) for film formation on a resist layer. 【Chemistry 2】 (Here, L １ , L ２ and L ３ Each of them is independently a single bond, C １－１０ Linear alkylene, C 3－１０ Branched-chain alkylenes, or C 3－１０ It is a cyclic alkylene, R １ , R ２ and R ３ These are H and C, respectively, independently. １－１０ Linear alkyl, C ３－１０ Branched-chain alkyl, C ３－１０ Cyclic alkyl, C ６－１５ Aryl or C ６－１５ It is Aralkir, R ４ C １－１５ Linear alkyl, C ３－１５ Branched-chain alkyl, C ３－１５ Cyclic alkyl, C ６－１５ Ariel, C ６－１５ Aralquil, or any combination thereof, Here, R ４ one or more hydrogen atoms in １－５ may be replaced by a C linear alkyl, -COOH or -OH, Here, L １ 、 L ２ 、 L ３ 、 R １ 、 R ２ 、 R ３ and R ４ Among them, one or more non - adjacent methylene (-CH ２ -) may be replaced by -O-, -S-, -CO-, -CO - O-, -O - CO-, -O - CO - O-, -CR ５ =CR ６ -, or -C≡C-, R ５ and R ６ These are, independently, H or C １－６ It is a linear alkyl group, X is either O or S, n is either 0 or 1.

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