Resist topcoat compositions and methods of forming patterns using the same

Abstract

To provide a resist topcoat composition capable of reducing pattern distribution by preventing or reducing pattern deterioration.SOLUTION: A topcoat composition according to one embodiment includes a copolymer including first and second structural units, represented by the following chemical formulae, respectively, an amide-based matting agent, and a solvent.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a composition for a resist upper layer film and a pattern forming method using the same. [Background technology]

[0002] Recently, the semiconductor industry has been evolving from patterns of hundreds of nanometers to ultra-fine technology with patterns of several to tens of nanometers. To realize such ultra-fine technology, an effective photolithography process is essential.

[0003] A typical photolithography process includes forming a material layer on a semiconductor substrate, coating a photoresist layer thereon, exposing and developing the material layer to form a photoresist pattern, and then etching the material layer using the formed photoresist pattern as a mask.

[0004] As photolithography technology advances, the degree of pattern integration increases, and new materials and technologies are required to solve various problems that arise during this process.

[0005] In particular, when EUV is irradiated onto photoresist, it is known that photo shot noise occurs, where areas are randomly irradiated with more or less light due to the large energy per photon, or pattern variation degradation such as pattern roughness (LER: Line Edge Roughness, LWR: Line Width Roughness) or IPU occurs due to the difference in EUV absorption between the top and bottom of the photoresist, and technological development to improve this is required. Summary of the Invention [Problem to be solved by the invention]

[0006] A composition for a resist upper layer film is provided that can prevent pattern deterioration and reduce pattern variation.

[0007] Another embodiment provides a pattern forming method using a resist top layer film composition. [Means for solving the problem]

[0008] One embodiment is a copolymer including a first structural unit represented by the following chemical formula M-1 and a second structural unit represented by the following chemical formula M-2: Amide-based quenchers, and A composition for a resist top layer film is provided, which contains a solvent. [Chemical formula M-1] [ka] [Chemical formula M-2] [ka] In the above chemical formula M-1 and chemical formula M-2, R 1 and R 2 are each independently a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, L 1 and L 2 each independently represents a single bond or a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, X 1 is a single bond, -O-, -S-, -S(O)-, -S(O)2-, -C(O)-, -(CO)O-, -O(CO), -O(CO)O-, -NR a -(where R a is hydrogen, deuterium, or a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms; R 3 is hydrogen, fluorine, a hydroxy group, or a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, R 4 is hydrogen, or C(=O)R b and R b is a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, R 3 , L 1 and L 2 at least one of which contains fluorine and a hydroxy group; R 5 is hydrogen, halogen, a hydroxy group, or a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, m1 is an integer from 1 to 4; * is the link position.

[0009] Another embodiment provides a pattern forming method including the steps of applying a photoresist composition onto a substrate and heating it to form a photoresist film, applying the above-described resist upper layer film composition onto the photoresist film and heating it to form an upper layer film, and exposing and developing the upper layer film and the photoresist film to form a resist pattern. [Effects of the Invention]

[0010] When the composition for a resist top layer film according to one embodiment is exposed to EUV, it removes excessively activated acid at the top of the photoresist, thereby preventing deterioration of pattern variations such as pattern roughness (LER, LWR) or IPU due to the difference in EUV absorption between the top and bottom of the photoresist, thereby improving variations and significantly improving IPU of pillar patterns, thereby advantageously being used for forming fine photoresist patterns. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram illustrating a pattern formation method using a resist upper layer film composition according to one embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] Although the present invention may be embodied in many different forms and is not limited to the embodiments set forth herein, the present invention will be described in detail below so that those skilled in the art can easily practice the present invention.

[0013] In the drawings, thicknesses of various layers and regions are exaggerated for clarity, and similar parts are designated by the same reference numerals throughout the specification. When a layer, film, region, plate, or other part is said to be "on" another part, this includes not only the case where it is "directly on" another part, but also the case where there is another part between them. Conversely, when a part is said to be "directly on" another part, it means that there is no other part between them.

[0014] Unless otherwise defined in this specification, "substituted" means that a hydrogen atom in a compound has been replaced with a halogen atom (F, Br, Cl, or I), a hydroxy group, a thiol group, a nitro group, a cyano group, an amino group, a substituted or unsubstituted amino group having 1 to 30 carbon atoms, an azido group, an amidino group, a hydrazino group, a hydrazono group, a carbonyl group, a carbamoyl group, a thiol group, an ester group, a carboxyl group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a vinyl group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, a carbonyl group, a carboxylic acid group or a salt thereof ... It means that the group is substituted with a substituent selected from an alkynyl group having 2 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms, an arylalkyl group having 7 to 30 carbon atoms, an alkoxy group having 1 to 30 carbon atoms, a sulfide group having 1 to 30 carbon atoms, a heteroalkyl group having 1 to 20 carbon atoms, a heteroarylalkyl group having 3 to 20 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, a cycloalkenyl group having 3 to 15 carbon atoms, a cycloalkynyl group having 6 to 15 carbon atoms, a heterocycloalkyl group having 3 to 30 carbon atoms, and combinations thereof.

[0015] In this description, unless otherwise defined, the term "alkyl group" refers to a straight-chain or branched-chain aliphatic hydrocarbon group. The alkyl group may be a "saturated alkyl group" that does not contain any double or triple bonds.

[0016] The alkyl group may be an alkyl group having 1 to 20 carbon atoms. More specifically, the alkyl group may be an alkyl group having 1 to 10 carbon atoms or an alkyl group having 1 to 6 carbon atoms. For example, an alkyl group having 1 to 5 carbon atoms means that the alkyl chain contains 1 to 5 carbon atoms and is selected from the group consisting of methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl groups.

[0017] Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, and a hexyl group.

[0018] In the chemical formulas described herein, t-Bu refers to a tert-butyl group.

[0019] In this description, unless otherwise defined, the term "cycloalkyl group" refers to a monovalent cyclic aliphatic hydrocarbon group.

[0020] The cycloalkyl group means a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and the like.

[0021] The cycloalkyl group may be a cycloalkyl group having 3 to 10 carbon atoms, for example, a cycloalkyl group having 3 to 8 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, or a cycloalkyl group having 3 to 6 carbon atoms. For example, the cycloalkyl group may be, but is not limited to, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, or a cyclohexyl group.

[0022] In this description, unless otherwise defined, the term "alkenyl group" refers to a straight-chain or branched-chain aliphatic hydrocarbon group containing one or more double bonds and an aliphatic unsaturated alkenyl group.

[0023] In this description, unless otherwise defined, the term "alkynyl group" refers to a straight-chain or branched-chain aliphatic hydrocarbon group, an aliphatic unsaturated alkynyl group containing one or more triple bonds.

[0024] In this description, "aryl group" means a substituent in which all elements of the cyclic substituent have p-orbitals and these p-orbitals form conjugation, including monocyclic or fused-ring polycyclic (i.e., rings that share adjacent pairs of carbon atoms) functional groups.

[0025] Unless otherwise defined in this specification, the term "hetero" means containing 1 to 10 heteroatoms independently selected from N, O, S, and P.

[0026] In this description, unless otherwise defined, the term "heterocycloalkyl group" means that the cycloalkyl group contains at least one heteroatom selected from the group consisting of N, O, S, P, and Si.

[0027] In this description, the term "heteroaryl group" refers to an aryl group containing at least one heteroatom selected from the group consisting of N, O, S, P, and Si. Two or more heteroaryl groups can be directly linked through a sigma bond, or, if the heteroaryl group contains two or more rings, the two or more rings can be fused together. If the heteroaryl group is a fused ring, each ring can contain 1 to 3 heteroatoms.

[0028] In this specification, the term "acrylic polymer" is a general term for acrylic polymers and methacrylic polymers.

[0029] Unless otherwise specified in this specification, the "weight average molecular weight" is measured by dissolving a powder sample in tetrahydrofuran (THF) and then using a 1200 series gel permeation chromatography (GPC) manufactured by Agilent Technologies (using a Shodex LF-804 column and Shodex polystyrene as the standard sample).

[0030] Additionally, unless otherwise defined in this specification, "*" indicates the linking position of a structural unit of a compound or a moiety of a compound.

[0031] A photoresist upper layer film composition according to one embodiment will be described below.

[0032] The present invention relates to a photoresist top layer film composition that can improve the sensitivity of photoresists during a fine pattern formation process in photolithography using high-energy rays such as EUV (Extreme ultraviolet; wavelength 13.5 nm) and simultaneously selectively reduce the acid concentration in the upper layer of the photoresist, thereby improving the in-point uniformity (IPU) of contact hole (C / H) patterns, the line edge roughness (LER) / line width roughness (LWR) of line and space (L / S) patterns, and the IPU of pillar patterns, and a method for forming a photoresist pattern using such a top layer film.

[0033] Specifically, a composition for a resist upper layer film according to one embodiment includes a copolymer including a first structural unit represented by the following chemical formula M-1 and a second structural unit represented by the following chemical formula M-2, an amide-based quencher, and a solvent. [Chemical formula M-1] [ka] [Chemical formula M-2] [ka] In the above chemical formula M-1 and chemical formula M-2, R 1 and R 2 are each independently a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, L 1 and L 2 each independently represents a single bond or a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, X 1 is a single bond, -O-, -S-, -S(O)-, -S(O)2-, -C(O)-, -(CO)O-, -O(CO), -O(CO)O-, -NR a -(where R a is hydrogen, deuterium, or a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms; R 3 is hydrogen, fluorine, a hydroxy group, or a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, R 4 is hydrogen, or C(=O)R b and R b is a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, R 3 , L 1 and L 2 at least one of which contains fluorine and a hydroxy group; R 5 is hydrogen, halogen, a hydroxy group, or a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, m1 is an integer from 1 to 4; * indicates the linking position.

[0034] The photoresist top layer composition according to one embodiment is applied to the top of a photoresist layer to not only increase the sensitivity of the photoresist but also significantly improve the LER / LWR of an L / S pattern, the IPU of a C / H pattern, and the IPU of a pillar pattern.

[0035] In addition, by using an amide-based quencher, exposure of the upper part of the photoresist layer selectively exposes amino groups in the exposed area, and the exposed amine selectively removes the activated acid in the exposed area, thereby improving the deteriorated area at the top of the pattern generated by the exposure process, i.e., the rounded profile of the upper layer of the photoresist, to a rectangular shape, thereby improving the IPU or LWR of the pattern.

[0036] The first structural unit contained in the copolymer in the composition is highly soluble in solvents that have little reactivity with photoresists, thereby minimizing the impact on the photoresist and protecting the photoresist, and the second structural unit enhances EUV absorption, thereby improving sensitivity.

[0037] Therefore, the copolymer has excellent solubility in a solvent, allowing for uniform coating of the pattern and minimizing the influence on the resist.

[0038] As an example, the copolymer may include a first structural unit represented by the chemical formula M-1 and a second structural unit represented by the chemical formula M-2.

[0039] In the chemical formula M-2, when m1 is 2 or more, each OR 4 may be the same as or different from each other.

[0040] In the chemical formula M-2, when 5-m1 is 2 or more, each R 5 may be the same as or different from each other.

[0041] R 3 , L 1 and L 2 At least one of the above contains fluorine and a hydroxy group. R 3 is an alkyl group having 1 to 20 carbon atoms substituted with at least one fluorine atom and at least one hydroxyl group, or L 1 and L 2at least one of which is an alkylene group having 1 to 10 carbon atoms substituted with one or more fluorine atoms and one or more hydroxy groups; or L 1 and L 2 at least one of the groups is an alkylene group having 1 to 10 carbon atoms substituted with one or more fluorine atoms, and at least one of the remaining groups is an alkylene group having 1 to 10 carbon atoms substituted with one or more hydroxy groups, or R 3 is fluorine and L 1 and L 2 at least one of which is an alkylene group having 1 to 10 carbon atoms substituted with one or more hydroxy groups, or R 3 is a hydroxy group, and L 1 and L 2 at least one of which is an alkylene group having 1 to 10 carbon atoms substituted with one or more fluorine atoms, or R 3 is an alkyl group having 1 to 10 carbon atoms substituted with one or more fluorine atoms and one or more hydroxy groups, or R 3 may include a case where the alkyl group has 1 to 10 carbon atoms and is substituted with one or more hydroxy groups and one or more fluoroalkyl groups having 1 to 10 carbon atoms.

[0042] As a specific example, the first structural unit is represented by the following chemical formula 1. [Chemical formula 1] [ka] In the above chemical formula 1, R 1 is hydrogen or a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, R k , R l , R m , R n , and R 3 are each independently hydrogen, fluorine, a hydroxy group, or a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, m2 and m3 each independently represent an integer from 1 to 10; X 1 is a single bond, -O-, -S-, -S(O)-, -S(O)2-, -C(O)-, -(CO)O-, -O(CO), -O(CO)O-, -NR a -(where R a is hydrogen, deuterium, or a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms; R k , R l , R m , R n , and R 3 At least one of the groups contains fluorine and a hydroxy group.

[0043] In Chemical Formula 1, when m2 is 2 or more, each R k may be the same as or different from each other.

[0044] In Chemical Formula 1, when m2 is 2 or more, each R l may be the same as or different from each other.

[0045] In chemical formula 1, when m3 is 2 or more, each R m may be the same as or different from each other.

[0046] In chemical formula 1, when m3 is 2 or more, each R n may be the same as or different from each other.

[0047] R k , R l , R m , R n , and R 3 At least one of the above contains fluorine and a hydroxy group. R k , R l , R m , R n , and R 3 at least one of which is independently a fluorine atom and a hydroxy group; or R k , Rl , R m , R n , and R 3 at least one of which independently contains an alkyl group having 1 to 10 carbon atoms substituted with one or more fluorine atoms and an alkyl group having 1 to 10 carbon atoms substituted with one or more hydroxy groups, or R k , R l , R m , R n , and R 3 at least one of which independently contains one or more hydroxy groups and one or more fluorine-substituted alkyl groups having 1 to 10 carbon atoms; or R k , R l , R m , R n , and R 3 at least one of which independently contains an alkyl group having 1 to 5 carbon atoms substituted with one or more hydroxy groups and one or more fluoroalkyl groups having 1 to 5 carbon atoms; or R k , R l , R m , R n , and R 3 at least one of the groups is fluorine and at least one of the remaining groups is a hydroxy group; or R k , R l , R m , R n , and R 3 at least one of the groups is fluorine, and at least one of the remaining groups contains an alkyl group having 1 to 10 carbon atoms substituted with one or more hydroxy groups, or R k , R l , R m , R n , and R 3 at least one of the groups is a hydroxy group, and at least one of the remaining groups contains an alkyl group having 1 to 10 carbon atoms substituted with one or more fluorine atoms, or R k , R l , R m , R n , and R3 and at least one of the remaining groups is an alkyl group having 1 to 20 carbon atoms substituted with one or more hydroxy groups.

[0048] For example, R 1 is hydrogen or a methyl group, X 1 is a single bond, -O- or -NR a -(where R a is hydrogen, deuterium, or a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms; R 3 may be a fluorine atom, a hydroxy group, an alkyl group having 1 to 10 carbon atoms substituted with at least one fluorine atom, or an alkyl group having 1 to 10 carbon atoms substituted with at least one hydroxy group.

[0049] As an example, R in Formula 1 m , R n , and R 3 At least one of the groups may contain fluorine and a hydroxy group.

[0050] As a specific example, R in Chemical Formula 1 m and R n At least one of R is fluorine or an alkyl group having 1 to 10 carbon atoms substituted with at least one fluorine atom, 5 may be a hydroxy group or an alkyl group having 1 to 10 carbon atoms substituted with at least one hydroxy group.

[0051] As a specific example, R in Chemical Formula 1 m and R n at least one of R is a hydroxy group or an alkyl group having 1 to 10 carbon atoms substituted with at least one hydroxy group; 3 may be fluorine or an alkyl group having 1 to 10 carbon atoms substituted with at least one fluorine atom.

[0052] As a specific example, R in Chemical Formula 1m is a hydroxy group or an alkyl group having 1 to 10 carbon atoms substituted with at least one hydroxy group, and R n is a fluorine atom or an alkyl group having 1 to 10 carbon atoms and substituted with at least one fluorine atom, and R 3 may be a hydroxy group, fluorine, or an alkyl group having 1 to 10 carbon atoms substituted with at least one of a fluorine group and a hydroxy group.

[0053] As a specific example, R in Chemical Formula 1 m and R n At least one of R is fluorine or an alkyl group having 1 to 10 carbon atoms substituted with at least one fluorine atom, 3 may be a hydroxy group, or an alkyl group having 1 to 5 carbon atoms substituted with at least one of a hydroxy group and a fluoroalkyl group having 1 to 5 carbon atoms.

[0054] For example, the first structural unit can be selected from Group I below. [Group I] [ka] In Group I above, R 1 are each independently hydrogen or a methyl group; * is the link position.

[0055] As a specific example, the second structural unit is represented by any one of the following chemical formulas 2-1 to 2-4. [Formula 2-1] [Formula 2-2] [Formula 2-3] [Formula 2-4] [ka] In the above chemical formulas 2-1 to 2-4, R 2 is hydrogen or a methyl group, R 4 , R 4a , and R 4bare each independently hydrogen or C(=O)R b and R b is a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms, R 5a , R 5b , R 5c , and R 5d are each independently a hydrogen atom, a halogen atom, a hydroxy group, or a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, * is the link position.

[0056] As an example, R 5 At least one of them may be a halogen.

[0057] As a specific example, R 5 At least one of the groups may be an iodo group.

[0058] When the second structural unit contains an iodine group, the sensitivity can be further improved.

[0059] For example, the second structural unit can be selected from Group II below. [Group II] [ka] [ka] In Group II above, R 2 are each independently hydrogen or a methyl group; * is the link position.

[0060] The copolymer can contain 50 to 99 mol % of the first structural unit and 1 to 50 mol % of the second structural unit.

[0061] For example, the copolymer may contain 70 to 99 mol% of the first structural unit and 1 to 30 mol% of the second structural unit, and most specifically, may contain 80 to 95 mol% of the first structural unit and 5 to 20 mol% of the second structural unit.

[0062] When the molar ratio of each structural unit contained in the copolymer is within the above range, the copolymer has excellent solubility in organic solvents and can be uniformly coated on a pattern.

[0063] The copolymer may have a weight-average molecular weight (Mw) of 1,000 g / mol to 50,000 g / mol. For example, the weight-average molecular weight may be, but is not limited to, about 2,000 g / mol to 30,000 g / mol, for example, about 3,000 g / mol to 20,000 g / mol, or about 4,000 g / mol to 10,000 g / mol. When the weight-average molecular weight of the copolymer is within the above range, the carbon content and solubility in a solvent of a composition for a resist top layer film containing the copolymer can be adjusted to optimize the composition.

[0064] The copolymer may be contained in an amount of 0.1 to 10% by weight based on the total weight of the composition for the resist top layer film. By containing the copolymer in this range, removal of the resist top layer film may be facilitated.

[0065] In a most specific embodiment, the copolymer may be selected from those listed in Group III below. [Group III] [ka] In the above Group III, x:y may be 99:1 to 90:10, specifically 99:1, 96:4, 95:5, 91:9 or 90:10.

[0066] According to an embodiment, the amide-based quencher may be a cyclic amide or a derivative thereof. More specifically, the amide-based quencher may be one selected from a cyclic amine protected by a protecting group, a derivative thereof, and a cyclic amide or a derivative thereof. The amide-based quencher is exposed as an amino group during exposure, thereby selectively quenching acid generated on the photoresist in the region where the amino group is exposed, thereby improving the pattern profile and IPU or LWR.

[0067] The amide-based quencher according to an embodiment may be at least one of compounds represented by the following Formula 3 and Formula 4: [Chemical formula 3] [Chemical formula 4] [ka] In Chemical Formula 3 and Chemical Formula 4, R 7 is a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms or a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms, R 8 ~R 20 each independently represents a hydrogen atom, a halogen atom, a hydroxy group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a combination thereof; n1 is an integer between 1 and 3, n2 is an integer from 1 to 4.

[0068] As an example, R 7 and R 16 may each independently be a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms or a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms.

[0069] As a specific example, R 7 and R 16may each independently be a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, a tert-pentyl group, a neo-pentyl group, an iso-pentyl group, a sec-pentyl group, a cyclobutyl group, a cyclopentyl group, or a cyclohexyl group.

[0070] In one embodiment, R 7 may be a tert-butyl group.

[0071] The amide-based quencher may be at least one of the compounds listed in Group IV below. [Group IV] [ka] .

[0072] The amide-based quencher is included in an amount of 0.1 to 40 parts by weight, for example, 0.1 to 30 parts by weight, for example, 0.5 to 30 parts by weight, based on 100 parts by weight of the copolymer. By including the amide-based quencher in the amount within the above range, the solubility can be optimized and the pattern LWR improvement effect can be ensured.

[0073] In addition, the composition for the resist top layer film may further include one or more different polymers selected from the group consisting of an acrylic resin, an epoxy resin, a novolac resin, a glycoluril resin, and a melamine resin, but is not limited thereto.

[0074] The resist top layer film composition may further include additives including a surfactant, a thermal acid generator, a plasticizer, or a combination thereof.

[0075] Examples of surfactants that can be used include, but are not limited to, alkylbenzene sulfonates, alkylpyridinium salts, polyethylene glycols, and quaternary ammonium salts.

[0076] Examples of the thermal acid generator that can be used include, but are not limited to, acidic compounds such as p-toluenesulfonic acid, trifluoromethanesulfonic acid, pyridinium p-toluenesulfonate, salicylic acid, sulfosalicylic acid, citric acid, benzoic acid, hydroxybenzoic acid, and naphthalenecarboxylic acid, and / or benzoin tosylate, 2-nitrobenzyl tosylate, and other organic sulfonic acid alkyl esters.

[0077] The amount of these additives used can be easily adjusted depending on the desired physical properties, and they can also be omitted.

[0078] The solvent may be an ether solvent, for example, represented by the following chemical formula 5. [Chemical formula 5] [ka] In the above chemical formula 5, R 21 and R 22 are each independently a substituted or unsubstituted alkyl group having 3 to 20 carbon atoms.

[0079] For example, the ether solvent may be selected from diisopropyl ether, dipropyl ether, diisoamyl ether, diamyl ether, dibutyl ether, diisobutyl ether, di-sec-butyl ether, dihexyl ether, bis(2-ethylhexyl) ether, didecyl ether, diundecyl ether, didodecyl ether, ditetradecyl ether, hexadecyl ether, butyl methyl ether, butyl ethyl ether, butyl propyl ether, tert-butyl methyl ether, tert-butyl ethyl ether, tert-butyl propyl ether, di-tert-butyl ether, cyclopentyl methyl ether, cyclohexyl methyl ether, cyclopentyl ethyl ether, cyclohexyl ethyl ether, cyclopentyl propyl ether, cyclopentyl-2-propyl ether, cyclohexyl propyl ether, cyclohexyl-2-propyl ether, cyclopentyl butyl ether, cyclopentyl-tert-butyl ether, cyclohexyl butyl ether, cyclohexyl-tert-butyl ether, and combinations thereof.

[0080] The ether solvent may have sufficient solubility or dispersibility for the above-mentioned composition.

[0081] According to another embodiment, there is provided a method for forming a pattern using the composition for a resist top layer film described above. For example, the formed pattern may be a photoresist pattern.

[0082] According to one embodiment, the method for forming a pattern includes the steps of applying a photoresist composition on a substrate and heating the composition to form a photoresist film, applying the composition for a photoresist upper layer film described above on the photoresist film and heating the composition to form an upper layer film, and exposing and developing the upper layer film and the photoresist film to form a resist pattern.

[0083] A method for forming a pattern using the above-described composition for a photoresist upper layer film will now be described with reference to Fig. 1. Fig. 1 is a schematic diagram for explaining the method for forming a pattern using the composition for a photoresist upper layer film according to the present invention.

[0084] Referring to FIG. 1, first, an etching target 100 is prepared. An example of the etching target may be a thin film formed on a semiconductor substrate. The following description will be limited to the case where the etching target is a thin film. The surface of the thin film is cleaned to remove contaminants remaining on the thin film. The thin film may be, for example, a silicon nitride film, a polysilicon film, or a silicon oxide film.

[0085] A photoresist composition is applied onto the thin film and heated to form a photoresist film 101 (1). Next, the above-described photoresist upper layer film composition is applied onto the photoresist film and heated to form a photoresist upper layer film 30 (2).

[0086] Heating can be carried out at a temperature of 80°C to 500°C.

[0087] The photoresist top layer and the photoresist film are then exposed to high energy radiation.

[0088] For example, high-energy radiation that can be used in the exposure step includes light having a high-energy wavelength such as EUV (Extreme UltraViolet; wavelength 13.5 nm) and E-Beam (electron beam).

[0089] Next, a post-exposure bake (PEB) step is performed. The post-exposure bake step can be performed at a temperature of about 80° C. to about 200° C. By performing the post-exposure bake step, the exposed areas of the photoresist film, i.e., the areas not covered by the patterned mask, are changed to have a property of being soluble in a developer, and thus have a different solubility from the unexposed areas of the photoresist film.

[0090] The photoresist film and the photoresist upper layer film corresponding to the exposed area are dissolved and removed using a developer, thereby forming a photoresist pattern 102b (3).

[0091] Specifically, the developer may be an alkaline developer or a developer containing an organic solvent (hereinafter referred to as an organic developer).

[0092] As the alkaline developer, a quaternary ammonium salt, typically tetramethylammonium hydroxide, is usually used, but other alkaline aqueous solutions such as inorganic alkalis, primary to tertiary amines, alcohol amines, and cyclic amines can also be used.

[0093] The alkaline developer may contain an appropriate amount of alcohols and / or surfactants. The alkaline developer may have an alkali concentration of, for example, 0.1 to 20% by mass, and a pH of, for example, 10 to 15.

[0094] The organic developer may be a developer containing at least one organic solvent selected from the group consisting of ketone solvents, ester solvents, alcohol solvents, amide solvents, ether solvents, and hydrocarbon solvents.

[0095] Examples of ketone solvents include 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 2-heptanone (methyl amyl ketone), 4-heptanone, 1-hexanone, 2-hexanone, diisobutyl ketone, cyclohexanone, methylcyclohexanone, phenylacetone, methyl ethyl ketone, methyl isobutyl ketone, acetylacetone, acetonylacetone, ionone, diacetonyl alcohol, acetylcarbinol, acetophenone, methyl naphthyl ketone, isophorone, and propylene carbonate.

[0096] Examples of ester-based solvents include methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, pentyl acetate, isopentyl acetate, amyl acetate, propylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl-3-ethoxypropionate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, methyl formate, ethyl formate, butyl formate, propyl formate, ethyl lactate, butyl lactate, propyl lactate, butyl butanoate, methyl 2-hydroxyisobutyrate, isoamyl acetate, isobutyl isobutyrate, and butyl propionate.

[0097] As the alcohol solvent, amide solvent, ether solvent, and hydrocarbon solvent, known solvents can be used.

[0098] The developer as a whole preferably has a water content of less than 50% by weight, more preferably less than 20% by weight, and even more preferably less than 10% by weight, and particularly preferably has a water content of substantially no water.

[0099] The content of the organic solvent in the organic developer is preferably 50 to 100% by weight, more preferably 80 to 100% by weight, further preferably 90 to 100% by weight, and particularly preferably 95 to 100% by weight, based on the total amount of the developer.

[0100] The organic developer may contain an appropriate amount of a known surfactant, if necessary.

[0101] The content of the surfactant is usually 0.001 to 5% by weight, preferably 0.005 to 2% by weight, and more preferably 0.01 to 0.5% by weight, based on the total amount of the developer.

[0102] The organic developer may contain the inhibitors described above.

[0103] The photoresist pattern is then applied as an etching mask to etch the exposed thin film, resulting in the thin film being formed into a thin film pattern.

[0104] The thin film can be etched by dry etching using an etching gas, such as CHF3, CF4, Cl2, BCl3, or a mixture thereof.

[0105] The thin film pattern formed using the photoresist pattern formed by the previous exposure process using an EUV light source may have a width corresponding to the photoresist pattern. For example, it may have a width of 5 nm to 100 nm, the same as the photoresist pattern. For example, the thin film pattern formed by the exposure process using an EUV light source may have a width of 5 nm to 90 nm, 5 nm to 80 nm, 5 nm to 70 nm, 5 nm to 60 nm, 5 nm to 50 nm, 5 nm to 40 nm, 5 nm to 30 nm, or 5 nm to 20 nm, similar to the photoresist pattern, and more specifically, may have a width of 20 nm or less. [Example]

[0106] The present invention will be described in more detail below through examples of the synthesis of the above-mentioned polymer and the preparation of a composition for a photoresist upper layer film containing the same, but the present invention is not technically limited by the following examples.

[0107] Synthesis Example Synthesis Example 1: Synthesis of Compound 1a Under a nitrogen atmosphere, 20 g (59.86 mmol) of hexafluoro-2,3-bis(trifluoromethyl)-2,3-butanediol (perfluoropinacol), 7.79 g (59.86 mmol) of 2-(hydroxyethyl)methacrylate, and 18.84 g (71.84 mmol) of triphenylphosphine (PH3P) were mixed with 110 mL of diethyl ether and stirred. After stirring for 30 minutes, the mixture was cooled to 0°C, and a mixture of 14.52 g (71.84 mmol) of diisopropyl azodicarboxylate (DIAD) and 35 mL of diethyl ether was slowly added dropwise over 2 hours. After stirring at room temperature (23°C) for 24 hours, the mixture was concentrated. The concentrated mixture was dissolved in dichloromethane and the synthesized product was isolated by column chromatography using silica gel. The mixture was again distilled under reduced pressure to synthesize 2-[3,3,3-Trifluoro-2-hydroxy-1,1,2-tris(trifluoromethyl)propoxy]ethyl 2-methyl-2-propenoate, represented by the following chemical formula 1a.

[0108] *1 H-NMR (Acetone-d6): δ1.90 (3H, t), 4.36 (4H, m), 5.63 (1H, t), 6.09 (1H, t), 8.34 (1H, s) *19 F-NMR (Acetone-d6): δ -70.12 (6F, m), -65.38 (6F, m)

[0109] [Chemical formula 1a] [ka]

[0110] Synthesis Example 2: Preparation of Copolymer R1 A 250 mL two-neck round bottom flask was charged with the compound represented by Formula 1a (16.1 g, 36 mmol), the compound represented by Formula 1b (DIVPA, manufactured by Songwon) (1.7 g, 4 mmol), and 110 g of diisoamyl ether (DIAE) under a nitrogen atmosphere and heated to an internal temperature of 85°C. Once the internal temperature reached 85°C, 14.7 g of a 25 wt% V-601 / DIAE solution (3.7 g, 16 mmol of V-601) was slowly added. After 6 hours, the reaction mixture was cooled to room temperature and concentrated to a solids content of 50%. 270 g of heptane was added to the concentrated solution, and the resulting polymer was filtered. The filtered polymer was completely dissolved in 34 g of DIAE, and then 270 g of heptane was added to precipitate it twice. After that, it was completely dried to finally prepare copolymer R1 (Mw = 4,000).

[0111] [Formula 1b] [ka] [ka] (x:y=90:10)

[0112] Synthesis Example 3: Preparation of Copolymer R2 Copolymer R2 (Mw=9,000) was prepared in the same manner as in Synthesis Example 2, except that a compound represented by the following Chemical Formula 2b (2,4-diiodo-6-vinylphenol, manufactured by Accela Chembio) (1.5 g, 16 mmol) was used instead of the compound represented by Chemical Formula 1b.

[0113] [Chemical formula 2b] [ka] [ka] (x:y=96:4)

[0114] Synthesis Example 4: Preparation of Copolymer R3 Copolymer R3 (Mw=5,000) was prepared in the same manner as in Synthesis Example 2, except that the compound represented by the following Chemical Formula 2a (10.6 g, 36 mmol) was used instead of the compound represented by Chemical Formula 1a.

[0115] [Chemical formula 2a] [ka] [ka] (x:y=90:10)

[0116] Synthesis Example 5: Preparation of Copolymer R4 Copolymer R4 (Mw=6,000) was prepared in the same manner as in Synthesis Example 2, except that the compound represented by Chemical Formula 2a (16.1 g, 36 mmol) was used instead of the compound represented by Chemical Formula 1a, and the compound represented by Chemical Formula 2b (1.5 g, 4 mmol) was used instead of the compound represented by Chemical Formula 1b.

[0117] [ka] (x:y=91:9)

[0118] Synthesis Example 6: Preparation of Copolymer R5 Copolymer R5 (Mw=5,000) was prepared in the same manner as in Synthesis Example 2, except that a compound represented by the following Chemical Formula 3a (MA-TTBD, manufactured by HALOCARBON) (10.1 g, 36 mmol) was used instead of the compound represented by Chemical Formula 1a.

[0119] [Chemical formula 3a] [ka] [ka] (x:y=90:10)

[0120] Synthesis Example 7: Preparation of Copolymer R6 Copolymer R6 (Mw=5,000) was prepared in the same manner as in Synthesis Example 2, except that the compound represented by Chemical Formula 3a (10.1 g, 36 mmol) was used instead of the compound represented by Chemical Formula 1a, and the compound represented by Chemical Formula 2b (1.5 g, 4 mmol) was used instead of the compound represented by Chemical Formula 1b.

[0121] [ka] (x:y=90:10)

[0122] Synthesis Example 8: Preparation of Copolymer R7 Copolymer R7 (Mw=5,000) was prepared in the same manner as in Synthesis Example 2, except that the compound represented by Chemical Formula 1b was not used. [ka] (x=100)

[0123] Production of composition for resist top layer film Example 1 0.98 g (0.5 wt %) of the copolymer R1 prepared in Synthesis Example 2 and 1.47 mg (0.15 wt %) of an amide-based quencher represented by Q1 below were dissolved in 199 g (w / w=97 / 30) of a DIAE / PGME mixed solvent, and the resulting mixture was stirred at room temperature (23° C.) for 24 hours. The mixture was then filtered through a Teflon filter with a 0.45 μm pore size to prepare a composition for a resist top layer film. Q1: [ka]

[0124] Examples 2 to 18 Each composition for a resist upper layer film was prepared in the same manner as in Example 1, except that the types of copolymer and amide-based quencher were changed as shown in Table 1 below. Q2: [ka] Q3: [ka] Q4: [ka]

[0125] Comparative Example 1 Each composition for a resist upper layer film was prepared in the same manner as in Example 1, except that the amide-based quencher was not used.

[0126] Comparative Example 2 Each composition for a resist upper layer film was prepared in the same manner as in Example 1, except that copolymer R7 prepared in Synthesis Example 8 was used instead of copolymer R1.

[0127] Evaluation 1: Solubility evaluation The compositions of Examples 1 to 10 and Comparative Example 1 were stirred for 24 hours, and then visually observed for the presence or absence of precipitate formation. The results are shown in Table 1 below. (No precipitate - Solubility ○, Precipitation - Solubility X)

[0128] Evaluation 2: Developability evaluation The photoresist top layer compositions prepared in the Examples and Comparative Examples were applied to silicon substrates by spin-on coating and then heat-treated on a hot plate at 110°C for 1 minute to form photoresist top layers with a thickness of approximately 5 nm. The substrates were then rinsed with a 2.38% tetramethylammonium hydroxide solution and heat-treated on a hot plate at 110°C for 1 minute. The thickness change of the top layer was measured, and the results are shown in Table 1 below. * Remaining film after development (%) = [Thickness of upper layer film before development (nm) - Thickness of upper layer film after development (nm)] × 100 / Thickness of upper layer film before development (nm) (Remaining film after development ≦ 20% - Developability OK, Remaining film after development > 20% - Developability X)

[0129] Evaluation 3: Sensitivity and LWR evaluation A resist underlayer film (50 Å thick) and an EUV photoresist thin film (700 Å thick) were formed on a 12-inch silicon substrate, and then the photoresist upper layer film compositions prepared in the Examples and Comparative Examples were applied by spin-on coating and then heat-treated on a hot plate at 110°C for 1 minute to form a photoresist upper layer film with a thickness of approximately 5 nm.

[0130] A line and space pattern was formed on a wafer with a photoresist top layer using the NXE3400B EUV equipment in the Focus-Energy Matrix (FEM) format. The optimum sensitivity for forming a critical dimension (CD) of 26.0 nm was confirmed using the interpolation method, and the results are shown in Table 1 below.

[0131] After confirming the optimum sensitivity, the line width roughness (LWR) variation was measured using a Hitachi CD-SEM device at the corresponding energy shot. To increase the reliability of the variation value, the same pattern was measured at 500 points within the shot, and the final average value is shown in Table 1 below.

[0132] [Table 1]

[0133] Referring to Table 1, it can be seen that when the composition for a resist top layer film according to the embodiment of the present invention is applied, not only is solubility, developability, and sensitivity excellent, but pattern deterioration is also suppressed and the LWR improvement effect is excellent.

[0134] On the other hand, in the case of the resist top layer film composition according to the comparative example, the LWR improvement effect was not observed or the sensitivity was reduced.

[0135] Although specific embodiments of the present invention have been described and illustrated above, it will be apparent to those skilled in the art that the present invention is not limited to the described embodiments and that various modifications and variations can be made without departing from the spirit and scope of the present invention. Therefore, such modifications and variations should not be understood separately from the technical spirit and perspective of the present invention, and the modified embodiments should be considered to fall within the scope of the claims of the present invention. [Explanation of symbols]

[0136] 1: Step of forming a photoresist film 2: Step of forming a photoresist upper layer film 3. Step 3: Exposing and developing the photoresist film and the photoresist top layer film to form a resist pattern. 30: Photoresist upper layer film 100: Substrate 101: Photoresist film 102b: Photoresist pattern

Claims

1. A copolymer comprising a first structural unit represented by the following chemical formula M-1 and a second structural unit represented by the following chemical formula M-2: Amide-based quenchers, and A composition for a resist upper layer film containing a solvent: [Chemical formula M-1] 【Chemical 1】 [Chemical formula M-2] 【Chemistry 2】 In the above chemical formula M-1 and chemical formula M-2, R １ and R ２ are each independently hydrogen or a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, L １ and L ２ each independently represents a single bond or a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, X １ is a single bond, -O-, -S-, -S(O)-, -S(O) ２ -, -C(O)-, -(CO)O-, -O(CO), -O(CO)O-, -NR ａ - (where R ａ is hydrogen, deuterium, or a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms; R ３ is hydrogen, fluorine, a hydroxy group, or a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, R ４ is hydrogen, or C(=O)R ｂ and R ｂ is a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, R ３ , L １ and L ２ at least one of which contains fluorine and a hydroxy group; R ５ is hydrogen, halogen, a hydroxy group, or a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms; m1 is one of the integers from 1 to 4; ＊ is the link position.

2. 2. The composition for a resist upper layer film according to claim 1, wherein the first structural unit is represented by the following chemical formula 1: [Chemical formula 1] 【Chemistry 3】 In the above chemical formula 1, R １ is hydrogen or a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, R ｋ , R ｌ , R ｍ , R ｎ , and R ３ are each independently hydrogen, fluorine, a hydroxy group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, or a combination thereof; m2 and m3 are each independently an integer from 1 to 10; X １ is a single bond, -O-, -S-, -S(O)-, -S(O) ２ -, -C(O)-, -(CO)O-, -O(CO), -O(CO)O-, -NR ａ - (where R ａ is hydrogen, deuterium, or a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms; R ｋ , R ｌ , R ｍ , R ｎ , and R ３ At least one of the groups contains fluorine and a hydroxy group.

3. 2. The composition for a resist upper layer film according to claim 1, wherein the first structural unit is at least one selected from the following Group I: [Group I] 【Chemistry 4】 In Group I, R １ are each independently hydrogen or a methyl group; ＊ is the link position.

4. The composition for a resist upper layer film according to claim 1, wherein the second structural unit is represented by any one of the following chemical formulas 2-1 to 2-4: [Chemical formula 2-1] [Chemical formula 2-2] [Chemical formula 2-3] [Chemical formula 2-4] 【Chemistry 5】 In the above chemical formulas 2-1 to 2-4, R ２ is hydrogen or a methyl group, R ４ , R ４ａ , and R ４ｂ are each independently hydrogen or C(═O)R ｂ and R ｂ is a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms, R ５ａ , R ５ｂ , R ５ｃ , and R ５ｄ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, or a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, ＊ is the link position.

5. The R ５ａ , R ５ｂ , R ５ｃ , and R ５ｄ The composition for a resist upper layer film according to claim 4 , wherein at least one of the groups is an iodo group.

6. 2. The composition for a resist upper layer film according to claim 1, wherein the second structural unit is at least one selected from the following Group II: [Group II] 【Chemistry 6】 【Chemistry 7】 In Group II, R ２ are each independently hydrogen or a methyl group; ＊ is the link position.

7. 2. The resist upper layer film composition according to claim 1, wherein the copolymer contains the first structural unit in an amount of 50 to 99 mol % and the second structural unit in an amount of 1 to 50 mol %.

8. 2. The composition for a resist upper layer film according to claim 1, wherein the weight average molecular weight of the copolymer is 1,000 g / mol to 50,000 g / mol.

9. 2. The composition for a resist upper layer film according to claim 1, wherein the amide-based quencher is a cyclic amide or a derivative thereof.

10. 2. The composition for a resist upper layer film according to claim 1, wherein the amide-based quencher is at least one of compounds represented by the following Chemical Formula 3 and Chemical Formula 4: [Chemical formula 3] [Chemical formula 4] 【Chemistry 8】 In Chemical Formula 3 and Chemical Formula 4, R ７ is a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms or a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms, R ８ ~R ２０ each independently represents a hydrogen atom, a halogen atom, a hydroxy group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a combination thereof; n1 is an integer from 1 to 3; n2 is an integer from 1 to 4.

11. 2. The composition for a resist upper layer film according to claim 1, wherein the amide-based quencher is at least one of the compounds listed in Group IV below: [Group IV] 【Chemistry 9】 。

12. 2. The composition for a resist upper layer film according to claim 1, wherein the amide-based quencher is contained in an amount of 0.1 to 50 parts by weight based on 100 parts by weight of the copolymer.

13. The composition for a resist upper layer film according to claim 1 , wherein the solvent is an ether-based solvent.

14. applying a photoresist composition onto a substrate and heating the composition to form a photoresist film; A step of applying the composition for a resist upper layer film according to any one of claims 1 to 13 onto the photoresist film and heating the composition to form an upper layer film; and The method for forming a pattern includes exposing and developing the upper layer film and the photoresist film to form a resist pattern.

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