Polymerizable monomer, high molecular compound, chemical amplification type resist composition, photomask blank, and method for producing resist pattern

Abstract

To provide a chemical amplification type resist composition capable of suppressing a development residue defect that causes a mask defect, while satisfying excellent resolution, a pattern shape, and line edge roughness, and a method for forming a resist pattern therewith.SOLUTION: A chemical amplification type resist composition that contains (A) a polymer compound comprising one or more types of repeating units, wherein at least one type of the repeating units contains the polymer compound in which residual oligomer of dimer-hexamer is a repeating unit obtained by polymerizing 1000 ppm or less of a polymerizable monomer.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a chemically amplified resist composition and a method of forming a resist pattern using the same. [Background technology]

[0002] In recent years, with the increasing integration and speed of LSIs, pattern rules have been rapidly becoming finer. Chemically amplified resists using acid as a catalyst are used exclusively for processing patterns of 0.2 μm or less. High-energy beams such as ultraviolet, far ultraviolet, and electron beams (EB) are also used as exposure sources. EB lithography, which is used as an ultrafine processing technology, is also indispensable as a processing method for photomask blanks when producing photomasks for semiconductor manufacturing.

[0003] Polymers with a large amount of aromatic skeletons with acidic side chains, such as polyhydroxystyrene, are useful as resist materials for KrF excimer lasers, but have not been used as resist materials for ArF excimer lasers because they exhibit high absorption at wavelengths around 200 nm. However, they are important materials for resist materials for EB, a powerful technology for forming patterns smaller than the processing limit of ArF excimer lasers, and for resist materials for extreme ultraviolet (EUV) light, as they offer high etching resistance.

[0004] Resist compositions used in such photolithography include positive-type resists that dissolve exposed areas to form a pattern, and negative-type resists that leave exposed areas to form a pattern, with the more convenient type being selected depending on the type of resist pattern required. Chemically amplified negative-type resist compositions typically contain a polymeric compound that dissolves in an aqueous alkaline developer, an acid generator that is decomposed by exposure light to generate an acid, and a crosslinking agent that uses acid as a catalyst to form crosslinks between the polymeric compounds to make them insoluble in the developer (in some cases, the polymeric compound and the crosslinking agent are integrated), or a compound that changes the polarity of the polymeric compound to make it insoluble in the developer. Furthermore, a basic compound is typically added to control the diffusion of the acid generated by exposure.

[0005] Examples of alkali-soluble units constituting the polymeric compound that dissolves in the aqueous alkaline developer include units derived from phenols. Many positive resist compositions and negative resist compositions of this type have been developed, particularly for exposure with KrF excimer laser light. However, these resist compositions have not been used for ArF excimer laser light because the units derived from phenols do not transmit light when the exposure light has a wavelength of 150 to 220 nm. However, in recent years, these resist compositions have once again attracted attention as positive and negative resist compositions for short-wavelength exposure, such as EB and EUV, which are exposure methods for obtaining finer patterns. For example, Patent Documents 1, 2, 3, and 4 have been reported.

[0006] In the photolithography, various improvements have been investigated to control resist sensitivity and pattern profile by selecting and combining basic compounds, which are acid generators and acid diffusion controllers used in resist compositions, and by changing process conditions, etc. For example, Patent Documents 5 and 6 have been reported.

[0007] On the other hand, as patterns become finer, defects caused by resist residues after development become a problem, causing scum residues and bridging between resist patterns, which can lead to a significant decrease in yield in the semiconductor manufacturing process, and improvements to reduce defects are strongly desired. As improved methods, removal of unreacted monomers from polymers is described in Patent Documents 7 and 8, and removal by filtration is described in Patent Documents 9 and 10. However, methods for removing unreacted monomers from polymers involve special crystallization processes or water washing separation, but these methods have problems such as the risk of removing necessary components and changing the properties of the polymer, a decrease in yield, and in some cases, difficulty in removing low-molecular-weight components from the polymer as intended.

[0008] Furthermore, column chromatography and filtration have productivity issues and are difficult to completely remove oligomers of about 2 to 8 monomers. Removal of oligomer components, which have a significant impact on development residues, is more important than removal of monomer components. These methods are insufficient, particularly for advanced lithography in semiconductor processes at the 14 nm node and beyond, and further improvements are needed. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-201532 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-215180 [Patent Document 3] Japanese Patent Application Laid-Open No. 2008-249762 [Patent Document 4] Japanese Patent Application Laid-Open No. 2008-95009 [Patent Document 5] Japanese Patent Application Laid-Open No. 2016-65016 [Patent Document 6] Japanese Patent Application Laid-Open No. 2016-200805 [Patent Document 7] Japanese Patent Application Laid-Open No. 2003-270788 [Patent Document 8] Japanese Patent Application Laid-Open No. 2006-274276 [Patent Document 9] Japanese Patent Application Laid-Open No. 2011-70033 [Patent Document 10] Japanese Patent Application Laid-Open No. 2005-189789 Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a chemically amplified resist composition that can suppress development residue defects that cause mask defects while satisfying good resolution, pattern shape, and line edge roughness, and a method of forming a resist pattern using the same. [Means for solving the problem]

[0011] In order to solve the above problems, the present invention provides: A chemically amplified resist composition, (A) A polymer compound containing one or more types of repeating units, wherein at least one of the repeating units is a repeating unit obtained by polymerizing a polymerizable monomer having a residual oligomer content of 2 to 6 monomers of 1000 ppm or less. The present invention provides a chemically amplified resist composition comprising:

[0012] In such a case, instead of purification being carried out at the polymer stage, the resist composition is a polymer of a material in which the content of oligomer components has been suppressed at the pre-polymerization monomer stage, and therefore, a chemically amplified resist composition can be obtained that satisfies good resolution, pattern shape, and line edge roughness, while suppressing development residue defects that cause mask defects.

[0013] The chemically amplified resist composition is a chemically amplified positive resist composition, and The component (A) is preferably a polymer compound containing a repeating unit A1 represented by the following general formula (A1), and the repeating unit A1 is preferably a repeating unit polymerized from a polymerizable monomer having a residual oligomer content of 1000 ppm or less, which is a dimer to hexamer: [ka] (In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 12 are each independently a halogen atom, an optionally halogen-substituted linear, branched, or cyclic acyloxy group having 2 to 8 carbon atoms, an optionally halogen-substituted linear, branched, or cyclic alkyl group having 1 to 6 carbon atoms, or an optionally halogen-substituted linear, branched, or cyclic alkoxy group having 1 to 6 carbon atoms. 2 is a single bond or a linear, branched or cyclic alkylene group having 1 to 11 carbon atoms, and an ether bond or an ester bond may be present between the carbon-carbon bond. s is 0 or 1. t is an integer of 0 to 2. c is an integer satisfying 0≦c≦5+2t-e. d is 0 or 1. e is an integer of 1 to 3. r is 0 or 1. X is an acid labile group when e is 1, and is a hydrogen atom or an acid labile group when e is 2 or more, provided that at least one X is an acid labile group.

[0014] The chemically amplified resist composition is a chemically amplified negative resist composition, and The component (A) is preferably a polymer compound containing a repeating unit A2 represented by the following general formula (A2), and the repeating unit A2 is preferably a repeating unit polymerized from a polymerizable monomer having a residual oligomer content of 2 to 6 monomers of 1000 ppm or less. [ka] (In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 1R is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and one -CH2- constituting the saturated hydrocarbylene group may be substituted with -O-. 1 are each independently a halogen atom, a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom. 1 represents a hydrogen atom, an aliphatic hydrocarbyl group having 1 to 10 carbon atoms, or an aryl group which may have a substituent, and the -CH2- constituting the aliphatic hydrocarbyl group may be replaced with -O-, -C(=O)-, -OC(=O)-, or -C(=O)-O-. Rx and Ry each independently represent a hydrogen atom, a saturated hydrocarbyl group having 1 to 15 carbon atoms which may be substituted with a hydroxy group or a saturated hydrocarbyloxy group, or an aryl group which may have a substituent. However, Rx and Ry cannot simultaneously be hydrogen atoms. Rx and Ry may also be bonded to each other to form a ring together with the carbon atoms to which they are attached. y is an integer of 0 to 2. u is 0 or 1. f is an integer which satisfies 0≦f≦5+2y-g. g is an integer of 1 to 3.

[0015] These repeating units that undergo a reaction due to the action of acid generated by exposure have a significant impact on defects in the resist composition, and therefore, the effects of the present invention can be maximized by suppressing the formation of oligomers in the polymerizable monomers that give rise to these repeating units.

[0016] The component (A) may also be a polymer compound containing a repeating unit A3 represented by the following general formula (A3). [ka] (In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 11are each independently a halogen atom, a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom. 1 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and one -CH2- constituting the saturated hydrocarbylene group may be substituted with -O-. s is 0 or 1. w is an integer of 0 to 2. a is an integer satisfying 0≦a≦5+2w-b. b is an integer of 1 to 3.

[0017] Furthermore, the component (A) may be a polymer compound containing at least one repeating unit selected from repeating units A4 to A11 represented by the following general formulas (A4) to (A11). [ka] (In the formula, R B are each independently a hydrogen atom or a methyl group. 1 represents a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these groups; -OZ 11 -, -C(=O)-OZ 11 - or -C(=O)-NH-Z 11 - and Z 11 Z is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, or a phenylene group, naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. 2 is a single bond or -Z 21 -C(=O)-O-, and Z 21 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. 3 represents a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -OZ 31 -, -C(=O)-OZ 31- or -C(=O)-NH-Z 31 - and Z 31 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, or a group having 7 to 20 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. 4 is a single bond or a hydrocarbylene group having 1 to 30 carbon atoms which may contain a heteroatom. 1 and k 2 are each independently 0 or 1, but Z 4 When is a single bond, k 1 and k 2 is 0. R 21 ~R 38 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 21 and R 22 may be bonded to each other to form a ring together with the sulfur atom to which they are attached, and R 23 and R 24 , R 26 and R 27 or R 29 and R 30 may be bonded to each other to form a ring together with the sulfur atom to which they are attached. HF is a hydrogen atom or a trifluoromethyl group. - is a non-nucleophilic counterion.

[0018] Furthermore, the component (A) may be a polymer compound containing at least one repeating unit selected from the group consisting of repeating units A12 to A14 represented by the following general formulae (A12), (A13) and (A14). [ka] (In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 13 and R 14are each independently a hydroxy group, a halogen atom, an acetoxy group, an optionally halogen-substituted linear, branched, or cyclic acyloxy group having 2 to 8 carbon atoms, an optionally halogen-substituted linear, branched, or cyclic alkyl group having 1 to 8 carbon atoms, an optionally halogen-substituted linear, branched, or cyclic alkoxy group having 1 to 8 carbon atoms, or an optionally halogen-substituted linear, branched, or cyclic alkylcarbonyloxy group having 2 to 8 carbon atoms. 15 A is an acetyl group, an acetoxy group, a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms, a linear, branched, or cyclic alkoxy group having 1 to 20 carbon atoms, a linear, branched, or cyclic acyloxy group having 2 to 20 carbon atoms, a linear, branched, or cyclic alkoxyalkyl group having 2 to 20 carbon atoms, an alkylthioalkyl group having 2 to 20 carbon atoms, a halogen atom, a nitro group, a cyano group, a sulfinyl group, or a sulfonyl group. 3 is a single bond or a linear, branched or cyclic alkylene group having 1 to 10 carbon atoms, and an ether bond may be present between the carbon-carbon bond. o and p are each independently an integer of 0 to 4. h is an integer of 0 or 1. j is an integer of 0 to 5. k is an integer of 0 to 2.

[0019] Such polymeric compounds can be suitably used as the component (A) in the present invention.

[0020] The chemically amplified resist composition is a chemically amplified positive resist composition, and The component (A) is preferably a polymeric compound that contains a repeating unit A1 represented by the general formula (A1) and a repeating unit A3 represented by the following general formula (A3), but does not contain repeating units A4 to A11 represented by the following general formulas (A4) to (A11). [ka] (In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 11are each independently a halogen atom, a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom. 1 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and one -CH2- constituting the saturated hydrocarbylene group may be substituted with -O-. s is 0 or 1. w is an integer of 0 to 2. a is an integer satisfying 0≦a≦5+2w-b. b is an integer of 1 to 3. [ka] (In the formula, R B are each independently a hydrogen atom or a methyl group. 1 represents a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these groups; -OZ 11 -, -C(=O)-OZ 11 - or -C(=O)-NH-Z 11 - and Z 11 Z is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, or a phenylene group, naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. 2 is a single bond or -Z 21 -C(=O)-O-, and Z 21 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. 3 represents a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -OZ 31 -, -C(=O)-OZ 31 - or -C(=O)-NH-Z 31 - and Z 31is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, or a group having 7 to 20 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. 4 is a single bond or a hydrocarbylene group having 1 to 30 carbon atoms which may contain a heteroatom. 1 and k 2 are each independently 0 or 1, but Z 4 When is a single bond, k 1 and k 2 is 0. R 21 ~R 38 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 21 and R 22 may be bonded to each other to form a ring together with the sulfur atom to which they are attached, and R 23 and R 24 , R 26 and R 27 or R 29 and R 30 may be bonded to each other to form a ring together with the sulfur atom to which they are attached. HF is a hydrogen atom or a trifluoromethyl group. - is a non-nucleophilic counterion.

[0021] When the chemically amplified resist composition of the present invention is a chemically amplified positive resist composition, the component (A) can be one of the above.

[0022] The chemically amplified resist composition is a chemically amplified negative resist composition, and The component (A) is preferably a polymeric compound that contains a repeating unit A2 represented by the general formula (A2) and a repeating unit A3 represented by the following general formula (A3), but does not contain repeating units A4 to A11 represented by the following general formulas (A4) to (A11). [ka] (In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 11 are each independently a halogen atom, a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom. 1 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and one -CH2- constituting the saturated hydrocarbylene group may be substituted with -O-. s is 0 or 1. w is an integer of 0 to 2. a is an integer satisfying 0≦a≦5+2w-b. b is an integer of 1 to 3. [ka] (In the formula, R B are each independently a hydrogen atom or a methyl group. 1 represents a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these groups; -OZ 11 -, -C(=O)-OZ 11 - or -C(=O)-NH-Z 11 - and Z 11 Z is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, or a phenylene group, naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. 2 is a single bond or -Z 21 -C(=O)-O-, and Z 21 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. 3 represents a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -OZ 31 -, -C(=O)-OZ 31 - or -C(=O)-NH-Z 31 - and Z 31is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, or a group having 7 to 20 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. 4 is a single bond or a hydrocarbylene group having 1 to 30 carbon atoms which may contain a heteroatom. 1 and k 2 are each independently 0 or 1, but Z 4 When is a single bond, k 1 and k 2 is 0. R 21 ~R 38 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 21 and R 22 may be bonded to each other to form a ring together with the sulfur atom to which they are attached, and R 23 and R 24 , R 26 and R 27 or R 29 and R 30 may be bonded to each other to form a ring together with the sulfur atom to which they are attached. HF is a hydrogen atom or a trifluoromethyl group. - is a non-nucleophilic counterion.

[0023] Furthermore, the component (A) is preferably a polymeric compound containing one or both of a repeating unit represented by the following general formula (A2-1) and a repeating unit represented by the following general formula (A2-2), a repeating unit represented by the following general formula (A3-1), and a repeating unit represented by the following general formula (A5-1). [ka] (In the formula, R Ais a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Rx and Ry each independently represent a hydrogen atom, a saturated hydrocarbyl group having 1 to 15 carbon atoms which may be substituted with a hydroxy group or a saturated hydrocarbyloxy group, or an aryl group which may have a substituent. However, Rx and Ry cannot simultaneously be hydrogen atoms. Rx and Ry may be bonded to each other to form a ring together with the carbon atoms to which they are bonded. g is an integer of 1 to 3. b is an integer of 1 to 3. R B are each independently a hydrogen atom or a methyl group. 2 is a single bond or -Z 21 -C(=O)-O-, and Z 21 R is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. 23 ~R 25 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 23 and R 24 may be bonded to each other to form a ring together with the sulfur atom to which they are attached.

[0024] When the chemically amplified resist composition of the present invention is a chemically amplified negative resist composition, the component (A) can be one of the above.

[0025] It is also preferred that the polymer compound of component (A) is a polymer of two or more polymerizable monomers, and that the total amount of residual dimer to hexamer oligomers contained in all of the polymerizable monomers is 5000 ppm or less.

[0026] If the component (A) is such, the occurrence of development residue defects can be more reliably suppressed.

[0027] Furthermore, the chemically amplified resist composition of the present invention preferably further contains (B) an acid generator.

[0028] This makes the composition more suitable as a chemically amplified resist composition.

[0029] The present invention also provides a photomask blank coated with the above-mentioned chemically amplified resist composition.

[0030] The chemically amplified resist composition of the present invention is particularly useful for pattern formation using photomask blanks as substrates.

[0031] In addition, in the present invention, (1) forming a resist film on a substrate using the chemically amplified resist composition; (2) irradiating the resist film with a pattern using high-energy radiation; and (3) A step of developing the patterned resist film using an alkaline developer. The present invention provides a method for forming a resist pattern, comprising the steps of:

[0032] In such a pattern formation method, since the chemically amplified resist composition of the present invention is used, it is possible to suppress development residue defects that cause mask defects while satisfying good resolution, pattern shape, and line edge roughness.

[0033] In this case, the high energy beam is preferably an ArF excimer laser beam, a KrF excimer laser beam, extreme ultraviolet light, or an electron beam.

[0034] Such high energy rays can be suitably used.

[0035] It is also preferable that the outermost surface of the substrate is made of a material containing at least one of chromium, silicon, tantalum, molybdenum, cobalt, nickel, tungsten, and tin.

[0036] The chemically amplified resist composition of the present invention can reduce development residues regardless of the type of substrate.

[0037] In addition, in the present invention, A method for producing a polymer compound containing one or more repeating units used in a chemically amplified resist composition, comprising: The present invention provides a method for producing a polymer compound by polymerizing at least one polymerizable monomer having a residual oligomer content of 2 to 6 monomers of 1000 ppm or less to obtain the polymer compound.

[0038] In this manner, rather than purifying at the polymer stage, a material in which the content of oligomer components is suppressed at the pre-polymerization monomer stage can be used to produce a polymer compound that can be used in a chemically amplified resist composition that satisfies good resolution, pattern shape, and line edge roughness, while suppressing development residue defects that cause mask defects.

[0039] It is also preferred that at least one of the repeating units obtained from the polymerizable monomers having a residual oligomer content of 2 to 6 monomers of 1000 ppm or less is a repeating unit A1 represented by the following general formula (A1). [ka] (In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 12 are each independently a halogen atom, an optionally halogen-substituted linear, branched, or cyclic acyloxy group having 2 to 8 carbon atoms, an optionally halogen-substituted linear, branched, or cyclic alkyl group having 1 to 6 carbon atoms, or an optionally halogen-substituted linear, branched, or cyclic alkoxy group having 1 to 6 carbon atoms. 2 is a single bond or a linear, branched or cyclic alkylene group having 1 to 11 carbon atoms, and an ether bond or an ester bond may be present between the carbon-carbon bond. s is 0 or 1. t is an integer of 0 to 2. c is an integer satisfying 0≦c≦5+2t-e. d is 0 or 1. e is an integer of 1 to 3. r is 0 or 1. X is an acid labile group when e is 1, and is a hydrogen atom or an acid labile group when e is 2 or more, provided that at least one X is an acid labile group.

[0040] It is also preferred that at least one of the repeating units obtained from the polymerizable monomers having a residual oligomer content of 2 to 6 monomers of 1000 ppm or less is a repeating unit A2 represented by the following general formula (A2). [ka] (In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 1 R is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and one -CH2- constituting the saturated hydrocarbylene group may be substituted with -O-. 1 are each independently a halogen atom, a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom. 1 represents a hydrogen atom, an aliphatic hydrocarbyl group having 1 to 10 carbon atoms, or an aryl group which may have a substituent, and the -CH2- constituting the aliphatic hydrocarbyl group may be replaced with -O-, -C(=O)-, -OC(=O)-, or -C(=O)-O-. Rx and Ry each independently represent a hydrogen atom, a saturated hydrocarbyl group having 1 to 15 carbon atoms which may be substituted with a hydroxy group or a saturated hydrocarbyloxy group, or an aryl group which may have a substituent. However, Rx and Ry cannot simultaneously be hydrogen atoms. Rx and Ry may also be bonded to each other to form a ring together with the carbon atoms to which they are attached. y is an integer of 0 to 2. u is 0 or 1. f is an integer which satisfies 0≦f≦5+2y-g. g is an integer of 1 to 3.

[0041] These repeating units that undergo a reaction due to the action of acid generated by exposure have a large effect on defects in the resist composition, so it is preferable to suppress the formation of oligomers in the polymerizable monomers that give rise to these repeating units. [Effects of the Invention]

[0042] The chemically amplified resist composition of the present invention does not undergo purification at the polymer stage, but rather contains a polymer of a material in which the content of oligomer components is suppressed at the pre-polymerization monomer stage. This makes it possible to provide a chemically amplified resist composition and a method for forming a resist pattern that can suppress development residue defects that cause mask defects while achieving good resolution, pattern shape, and line edge roughness.

[0043] A pattern formation method using the chemically amplified resist composition of the present invention can suppress development residue defects while satisfying the requirements of pattern formation with high resolution and reduced LER, and therefore can be suitably used in microfabrication techniques, particularly ArF, KrF, EUV, and EB lithography. DETAILED DESCRIPTION OF THE INVENTION

[0044] As described above, there has been a need for the development of a chemically amplified resist composition that can suppress development residue defects that cause mask defects while satisfying the requirements for good resolution, pattern shape, and line edge roughness.

[0045] As a result of extensive investigations into achieving the above-mentioned object, the inventors have discovered that when a polymeric compound having a repeating unit polymerized using a specific polymerizable monomer is incorporated into a resist composition, it is possible to achieve good resolution, pattern shape, and line edge roughness while suppressing development residue defects that cause mask defects, and have thereby completed the present invention.

[0046] That is, the present invention provides a chemically amplified resist composition, (A) A polymer compound containing one or more types of repeating units, wherein at least one of the repeating units is a repeating unit obtained by polymerizing a polymerizable monomer having a residual oligomer content of 2 to 6 monomers of 1000 ppm or less. The chemically amplified resist composition contains the above.

[0047] The present invention will be described in detail below, but the present invention is not limited thereto.

[0048] [Chemically amplified resist composition] The resist composition of the present invention is a chemically amplified resist composition that contains (A) a polymeric compound containing one or more types of repeating units, wherein at least one or more of the repeating units is a repeating unit formed by polymerization of a polymerizable monomer in which a residual oligomer of 2 to 6 is 1000 ppm or less.

[0049] [(A) Polymer compound] In order to obtain the polymer compound (A) used in the present invention, the polymerizable monomer synthesized for polymerizing the polymer compound is generally purified by any method, including, but not limited to, washing with water, separation, distillation, recrystallization, filtration, ultrafiltration, centrifugation, high performance liquid chromatography, column chromatography, etc.

[0050] In at least one repeating unit of component (A), the residual dimer to hexamer oligomer contained in the polymerizable monomer is 1000 ppm or less, more preferably 500 ppm or less, even more preferably 300 ppm or less, extremely preferably 200 ppm or less, and particularly preferably 100 ppm or less. It is preferable to control the dimer to hexamer oligomer, and particularly the dimer to tetramer oligomer.

[0051] Furthermore, if heating is required for solution formation during the purification step or extraction after purification, or if the product is to be stored for a long period after purification, a polymerization inhibitor such as TBC or BHT may be added as a stabilizer.

[0052] When a polymer compound polymerized using only polymerizable monomers in which the above oligomer component content exceeds 1000 ppm is used as a resist composition, development residue defects may occur, which may result in a significant decrease in yield in the semiconductor manufacturing process.

[0053] The remaining oligomers can be analyzed by LC-MS.

[0054] In the polymer compound of component (A), the proportion of repeating units polymerized from polymerizable monomers having a residual oligomer content of 2 to 6 monomers of 1000 ppm or less is not particularly limited, but is preferably 5 mol % or more, more preferably 10 mol % or more, even more preferably 20 mol % or more, extremely preferably 30 mol % or more, particularly preferably 40 mol % or more, even more preferably 80 mol % or more, and even more preferably 100 mol %.

[0055] Furthermore, any repeating unit among the one or more repeating units contained in the polymer compound of component (A) can be selected as a repeating unit polymerized from a polymerizable monomer having a residual oligomer content of 1000 ppm or less, i.e., any repeating unit described below as a repeating unit contained in the polymer compound of component (A).

[0056] The polymerizable monomer used in the present invention preferably contains a polymerizable monomer that provides a unit having a mechanism in which an acid-leaving group undergoes a elimination reaction under the action of acid generated by exposure, thereby rendering the resist composition soluble in an alkaline developer, or a polymerizable monomer that provides a unit having an acid-leaving group undergoes a elimination reaction, thereby rendering the resist composition insoluble in an alkaline developer, in a concentration of 2- to 6-mer residual oligomers of 1000 ppm or less, more preferably 500 ppm or less, even more preferably 300 ppm or less, extremely preferably 200 ppm or less, and particularly preferably 100 ppm or less. Control of oligomers is also preferably limited to 2- to 4-mer oligomers. Units that undergo a reaction under the action of acid generated by exposure have a significant impact on defects in the resist composition, so suppression of oligomers is important.

[0057] <Repeating unit A1> When the chemically amplified resist composition of the present invention is a chemically amplified positive resist composition, it preferably contains a repeating unit A1 represented by the following general formula (A1) as a unit having a mechanism for causing an elimination reaction of an acid-leaving group to become soluble in an alkaline developer. In this case, it is also preferable that the repeating unit A1 is a repeating unit polymerized from a polymerizable monomer having a residual oligomer content of 1000 ppm or less of dimer to hexamer.

[0058] [ka] (In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 12 are each independently a halogen atom, an optionally halogen-substituted linear, branched, or cyclic acyloxy group having 2 to 8 carbon atoms, an optionally halogen-substituted linear, branched, or cyclic alkyl group having 1 to 6 carbon atoms, or an optionally halogen-substituted linear, branched, or cyclic alkoxy group having 1 to 6 carbon atoms. 2 is a single bond or a linear, branched or cyclic alkylene group having 1 to 11 carbon atoms, and an ether bond or an ester bond may be present between the carbon-carbon bond. s is 0 or 1. t is an integer of 0 to 2. c is an integer satisfying 0≦c≦5+2t-e. d is 0 or 1. e is an integer of 1 to 3. r is 0 or 1. X is an acid labile group when e is 1, and is a hydrogen atom or an acid labile group when e is 2 or more, provided that at least one X is an acid labile group.

[0059] The repeating unit A1 is one in which at least one phenolic hydroxy group bonded to an aromatic ring is protected with an acid labile group, one in which a carboxyl group bonded to an aromatic ring is protected with an acid labile group, or one in which a carboxyl group contained in a (meth)acrylate is protected with an acid labile group. Such an acid labile group is not particularly limited, and any acid labile group that has been used in many known chemically amplified resist compositions and that is cleaved by an acid to give an acidic group can be used.

[0060] Among the repeating units contained in the polymer compound of component (A) according to the present invention, the repeating unit having an acid labile group represented by the repeating unit in general formula (A1) above is one in which a hydrogen atom of a phenolic hydroxyl group, preferably a hydroxyl group of hydroxystyrene or hydroxyphenyl(meth)acrylate, has been substituted. Examples of monomers from which this can be obtained include the monomers described in paragraph

[0029] of JP 2014-219657 A. When d is 1, the repeating unit having an acid labile group represented by the repeating unit in general formula (A1) above is one in which a hydrogen atom of a carboxyl group, particularly a hydroxyl group of (meth)acrylate, has been substituted. Examples of monomers from which this can be obtained include the monomers described in paragraph

[0028] of JP 2014-219657 A.

[0061] Examples of the structure of the acid labile group include the monomers described in paragraphs

[0030] to

[0082] of JP-A No. 2014-219657. Specific examples of preferred structures of the acid labile group include those of formulas (H-3)-1 to (H-3)-19 shown below.

[0062] [ka]

[0063] In formulas (H-3)-1 to (H-3)-19, R L43 R represents the same or different saturated hydrocarbyl groups or aryl groups having 6 to 20 carbon atoms, such as phenyl groups. L44 , R L46 is a hydrogen atom or a saturated hydrocarbyl group having 1 to 20 carbon atoms. L45 R represents an aryl group having 6 to 20 carbon atoms, such as a phenyl group. The saturated hydrocarbyl group may be linear, branched, or cyclic. The aryl group is preferably a phenyl group. F is a fluorine atom or a trifluoromethyl group, and n is an integer of 1 to 5.

[0064] Selecting a tertiary alkyl group as the acid labile group is preferable because it provides a pattern with a small LER even when the resist film is formed to a thickness of, for example, 10 to 100 nm and a fine pattern with a line width of 45 nm or less is formed. The tertiary alkyl group preferably has 4 to 18 carbon atoms so that the resulting polymerization monomer can be obtained by distillation. Examples of alkyl substituents on the tertiary carbon of the tertiary alkyl group include linear, branched, or cyclic alkyl groups having 1 to 20 carbon atoms, which may contain an oxygen-containing functional group such as an ether group or a carbonyl group, and the alkyl substituents on the tertiary carbon may be bonded to each other to form a ring.

[0065] Specific examples of the alkyl substituent on the tertiary carbon include a methyl group, an ethyl group, a propyl group, an adamantyl group, a norbornyl group, a tetrahydrofuran-2-yl group, a 7-oxanorbornan-2-yl group, a cyclopentyl group, a 2-tetrahydrofuryl group, a tricyclo[5.2.1.0 2,6 ]decyl group, tetracyclo[4.4.0.1 2,5 .1 7,10 ]dodecyl group, and 3-oxo-1-cyclohexyl group.

[0066] Examples of tertiary alkyl groups having these as substituents include tert-butyl, tert-pentyl, 1-ethyl-1-methylpropyl, 1,1-diethylpropyl, 1,1,2-trimethylpropyl, 1-adamantyl-1-methylethyl, 1-methyl-1-(2-norbornyl)ethyl, 1-methyl-1-(tetrahydrofuran-2-yl)ethyl, 1-methyl-1-(7-oxanorbornan-2-yl)ethyl, 1-methylcyclopentyl, 1-ethylcyclopentyl, 1-propyl Pyrcyclopentyl group, 1-isopropylcyclopentyl group, 1-cyclopentylcyclopentyl group, 1-cyclohexylcyclopentyl group, 1-(2-tetrahydrofuryl)cyclopentyl group, 1-(7-oxanorbornan-2-yl)cyclopentyl group, 1-methylcyclohexyl group, 1-ethylcyclohexyl group, 1-cyclopentylcyclohexyl group, 1-cyclohexylcyclohexyl group, 2-methyl-2-norbornyl group, 2-ethyl-2-norbornyl group, 8-methyl-8-tricyclo[5.2.1.0] 2,6 ]decyl group, 8-ethyl-8-tricyclo[5.2.1.0 2,6 ]decyl group, 3-methyl-3-tetracyclo[4.4.0.1 2,5 .1 7,10 ]dodecyl group, 3-ethyl-3-tetracyclo[4.4.0.1 2,5 .1 7,10 ]dodecyl group, 2-methyl-2-adamantyl group, 2-ethyl-2-adamantyl group, 2-isopropyl-2-adamantyl group, 1-methyl-3-oxo-1-cyclohexyl group, 1-methyl-1-(tetrahydrofuran-2-yl)ethyl group, 5-hydroxy-2-methyl-2-adamantyl group, 5-hydroxy-2-ethyl-2-adamantyl group, and the like, and preferably the structure shown below.

[0067] [ka]

[0068] [ka]

[0069] [ka]

[0070] [ka]

[0071] Furthermore, an acetal group represented by the following general formula (B2-1) is often used as an acid labile group, and is a useful option as an acid labile group that stably gives a pattern in which the interface between the pattern and the substrate is relatively rectangular.

[0072] [ka]

[0073] In the formula, R 16 is a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms. Y is a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms.

[0074] R 16 is selected appropriately depending on the design of the sensitivity of the decomposable group to acid. For example, if the design is to ensure relatively high stability while being decomposed by strong acid, a hydrogen atom is selected, and if the design is to use relatively high reactivity to achieve high sensitivity to pH changes, a straight-chain alkyl group is selected. Depending on the combination with the acid generator and basic compound to be compounded in the resist composition, if a relatively large alkyl group is substituted at the end and a large change in solubility due to decomposition is designed, R 16 Preferably, the carbon bonded to the acetal carbon is a secondary carbon. 16 Examples of the alkyl group include an isopropyl group, a sec-butyl group, a cyclopentyl group, and a cyclohexyl group.

[0075] In order to obtain higher resolution, Y of the acetal group is preferably a polycyclic alkyl group having 7 to 30 carbon atoms. Furthermore, when Y is a polycyclic alkyl group, it is preferable that a bond is formed between a secondary carbon constituting the polycyclic ring structure and the acetal oxygen. When Y is bonded to a secondary carbon of the ring structure, the polymer becomes a more stable compound than when Y is bonded to a tertiary carbon, resulting in better storage stability as a resist composition and no deterioration in resolution. Furthermore, compared to when Y is bonded to a primary carbon via a linear alkyl group having 1 or more carbon atoms, the polymer has a better glass transition temperature (Tg), and the developed resist pattern does not suffer from shape defects due to baking.

[0076] Preferred examples of the acetal group represented by general formula (B2-1) include, but are not limited to, the following: 16 is the same as above.

[0077] [ka]

[0078] The repeating unit A1 is preferably introduced in a range of 5 to 70 mol %, more preferably 5 to 60 mol %, based on all repeating units of the polymer compound of component (A).

[0079] <Repeating unit A2> In the case of a chemically amplified negative resist composition of the present invention, it is preferable that the chemically amplified resist composition contains a repeating unit A2 represented by the following general formula (A2) as a unit having a mechanism in which an acid-leaving group undergoes an elimination reaction and becomes insoluble in an alkaline developer. In this case, it is also preferable that the repeating unit A2 is a repeating unit polymerized from a polymerizable monomer having a residual oligomer content of 1000 ppm or less of dimer to hexamer.

[0080] [ka] (In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 1 R is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and one -CH2- constituting the saturated hydrocarbylene group may be substituted with -O-. 1 are each independently a halogen atom, a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom. 1 represents a hydrogen atom, an aliphatic hydrocarbyl group having 1 to 10 carbon atoms, or an aryl group which may have a substituent, and the -CH2- constituting the aliphatic hydrocarbyl group may be replaced with -O-, -C(=O)-, -OC(=O)-, or -C(=O)-O-. Rx and Ry each independently represent a hydrogen atom, a saturated hydrocarbyl group having 1 to 15 carbon atoms which may be substituted with a hydroxy group or a saturated hydrocarbyloxy group, or an aryl group which may have a substituent. However, Rx and Ry cannot simultaneously be hydrogen atoms. Rx and Ry may also be bonded to each other to form a ring together with the carbon atoms to which they are attached. y is an integer of 0 to 2. u is 0 or 1. f is an integer which satisfies 0≦f≦5+2y-g. g is an integer of 1 to 3.

[0081] The repeating unit A2 is a repeating unit that, when irradiated with high-energy rays, causes the acid-leaving group to undergo a elimination reaction due to the action of the acid generated from the acid generator, thereby inducing alkali insolubilization and crosslinking between polymers. The action of the repeating unit A2 makes the negative conversion reaction more efficient, thereby improving resolution performance.

[0082] W 1Examples of the aliphatic hydrocarbyl group having 1 to 10 carbon atoms represented by the formula (I) or the aryl group (aliphatic monovalent hydrocarbon group or monovalent aromatic ring group) which may have a substituent include a methyl group, an ethyl group, a propyl group, an isopropyl group, a cyclopentyl group, a cyclohexyl group, an adamantyl group, a methylcarbonyl group, and a phenyl group.

[0083] Preferred examples of Rx or Ry include a methyl group, an ethyl group, a propyl group, a butyl group, and structural isomers thereof, as well as isomers in which some of the hydrogen atoms are substituted with a hydroxy group or an alkoxy group.

[0084] y is an integer of 0 to 2, and when y is 0 it is a benzene ring, when y is 1 it is a naphthalene ring, and when y is 2 it is an anthracene ring.

[0085] A 1 Examples of alkylene groups represented by the formula (A2) include methylene, ethylene, propylene, butylene, pentylene, hexylene, and structural isomers of carbon skeletons having a branched or cyclic structure. When the alkylene group contains an ether bond, when u in general formula (A2) is 1, the ether bond may be located anywhere except between the carbon at the α-position and the carbon at the β-position relative to the ester oxygen. When u is 0, the atom bonding to the main chain may be an ether bond, and a second ether bond may be located anywhere except between the carbon at the α-position and the carbon at the β-position relative to the ether bond.

[0086] The repeating unit A2 is preferably a repeating unit represented by the following general formula (A2-1) or (A2-2).

[0087] [ka] (In the formula, R A , Rx, Ry and g are the same as above.)

[0088] Preferred examples of the repeating unit A2 include, but are not limited to, the following: In the following examples, Me is a methyl group, and Ac is an acetyl group.

[0089] [ka]

[0090] [ka]

[0091] [ka]

[0092] [ka]

[0093] [ka]

[0094] The content of the repeating unit A2 in all repeating units constituting the polymer compound of component (A) is preferably 5 mol % or more preferably 10 mol %, and the upper limit is preferably 70 mol %, more preferably 60 mol %.

[0095] <Repeating unit A3> The polymeric compound of the component (A) used in the chemically amplified resist composition of the present invention preferably further contains a repeating unit A3 represented by the following general formula (A3).

[0096] [ka] (In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 11are each independently a halogen atom, a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom. 1 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and one -CH2- constituting the saturated hydrocarbylene group may be substituted with -O-. s is 0 or 1. w is an integer of 0 to 2. a is an integer satisfying 0≦a≦5+2w-b. b is an integer of 1 to 3.

[0097] Linker (-CO-OA 1 -) (i.e., in the general formula (A3), s is 0 and A 1 is a single bond), preferred examples of the repeating unit A3 include units derived from 3-hydroxystyrene, 4-hydroxystyrene, 5-hydroxy-2-vinylnaphthalene, 6-hydroxy-2-vinylnaphthalene, etc. Among these, more preferred are repeating units represented by the following general formula (A3-1):

[0098] [ka] (In the formula, R A and b are the same as above.)

[0099] Linker (-CO-OA 1 When the repeating unit A3 has a repeating unit A3-(-), preferred examples of the repeating unit A3 include, but are not limited to, those shown below.

[0100] [ka]

[0101] The repeating unit A3 may be used alone or in combination of two or more types. The repeating unit A3 is preferably introduced in an amount of 10 to 95 mol %, more preferably 30 to 85 mol %, of all repeating units in the polymer compound of component (A). However, when the polymer contains at least one repeating unit represented by general formula (A12) or (A13), which is used in the present invention and described below and which imparts high etching resistance to the polymer, and this unit has a phenolic hydroxy group as a substituent, the proportion of the repeating unit A3 should also be within the above range.

[0102] <Repeating units A4 to A11> The chemically amplified resist composition of the present invention may further contain at least one repeating unit selected from the repeating units represented by the following general formulas (A4) to (A11).

[0103] [ka] (In the formula, R B are each independently a hydrogen atom or a methyl group. 1 represents a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these groups; -OZ 11 -, -C(=O)-OZ 11 - or -C(=O)-NH-Z 11 - and Z 11 Z is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, or a phenylene group, naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. 2 is a single bond or -Z 21 -C(=O)-O-, and Z 21 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. 3 represents a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -OZ 31-, -C(=O)-OZ 31 - or -C(=O)-NH-Z 31 - and Z 31 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, or a group having 7 to 20 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. 4 is a single bond or a hydrocarbylene group having 1 to 30 carbon atoms which may contain a heteroatom. 1 and k 2 are each independently 0 or 1, but Z 4 When is a single bond, k 1 and k 2 is 0. R 21 ~R 38 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 21 and R 22 may be bonded to each other to form a ring together with the sulfur atom to which they are attached, and R 23 and R 24 , R 26 and R 27 or R 29 and R 30 may be bonded to each other to form a ring together with the sulfur atom to which they are attached. HF is a hydrogen atom or a trifluoromethyl group. - is a non-nucleophilic counterion.

[0104] In general formula (A5, A9), Z 2 Ga-Z 21 -C(=O)-O-, Z 21 Examples of hydrocarbylene groups (divalent hydrocarbon groups) having 1 to 20 carbon atoms and optionally containing a heteroatom, represented by the following formula, include, but are not limited to, those shown below.

[0105] [ka] (In the formula, the dashed lines represent bonds.)

[0106] In the repeating units A4 and A8, Xa - Examples of non-nucleophilic counter ions represented by the formula (I) include those described in JP-A-2010-113209 and JP-A-2007-145797. HF Specific examples of when R is a hydrogen atom include those described in JP-A-2010-116550. HF Specific examples of repeating units A6 and A10 in which is a trifluoromethyl group include those described in JP-A No. 2010-77404. Examples of repeating units A6 and A10 include those described in JP-A No. 2012-246265 and JP-A No. 2012-246426.

[0107] Preferred examples of the anionic moiety of the monomer that provides the repeating units A7 and A11 include, but are not limited to, the following.

[0108] [ka]

[0109] [ka]

[0110] In general formulas (A4) to (A11), R 21 ~R 38are each independently a hydrocarbyl group having 1 to 20 carbon atoms, which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated and may be linear, branched, or cyclic. Specific examples include those exemplified in paragraphs

[0022] and

[0023] of JP 2010-116550 A. In addition, some or all of the hydrogen atoms in the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, nitrogen atom, or halogen atom. A group containing a heteroatom such as an oxygen atom, sulfur atom, or nitrogen atom may be present between the carbon-carbon bonds of the hydrocarbyl group, resulting in the hydrocarbyl group containing a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, or the like.

[0111] Also, R 21 and R 22 may be bonded to each other to form a ring together with the sulfur atom to which they are attached, and R 23 and R 24 , R 26 and R 27 , or R 29 and R 30 However, they may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. Examples of the ring formed in this case include the rings shown below.

[0112] [ka] (In the formula, R 32 is R 21 ~R 38 is the same as the group represented by

[0113] In the general formulae (A5) to (A7), specific structures of the sulfonium cation include, but are not limited to, those shown below.

[0114] [ka]

[0115]

change

[0116]

change

[0117]

change

[0118]

change

[0119]

change

[0120]

change

[0121]

change

[0122]

change

[0123]

change

[0124]

change

[0125] [ka]

[0126] [ka]

[0127] [ka]

[0128] [ka]

[0129] [ka]

[0130] [ka]

[0131] [ka]

[0132] In the general formulae (A9) to (A11), specific structures of the iodonium cation include, but are not limited to, those shown below.

[0133] [ka]

[0134] The repeating units A4 to A11 are units that generate acid upon irradiation with high-energy rays. It is believed that the inclusion of these units in the polymer appropriately suppresses acid diffusion, resulting in a pattern with reduced LER. Furthermore, the inclusion of these units in the polymer suppresses the phenomenon in which acid volatilizes from exposed areas and reattaches to unexposed areas during baking in a vacuum. This is believed to be effective in reducing LER and, in the case of negative-type films, in reducing defects due to unwanted negativity reactions in unexposed areas. It is also believed to be effective in reducing shape deterioration due to film loss in the case of positive-type films. The content of the repeating units A4 to A11 is preferably 0.1 to 30 mol %, more preferably 0.5 to 20 mol %, of the total repeating units constituting the polymer compound.

[0135] <Repeating units A12 to A14> The polymer compound of component (A) may contain at least one repeating unit selected from repeating units A12 to A14 represented by the following general formulas (A12) to (A14) for the purpose of improving etching resistance.

[0136] [ka] (In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 13 and R 14 are each independently a hydroxy group, a halogen atom, an acetoxy group, an optionally halogen-substituted linear, branched, or cyclic acyloxy group having 2 to 8 carbon atoms, an optionally halogen-substituted linear, branched, or cyclic alkyl group having 1 to 8 carbon atoms, an optionally halogen-substituted linear, branched, or cyclic alkoxy group having 1 to 8 carbon atoms, or an optionally halogen-substituted linear, branched, or cyclic alkylcarbonyloxy group having 2 to 8 carbon atoms. 15A is an acetyl group, an acetoxy group, a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms, a linear, branched, or cyclic alkoxy group having 1 to 20 carbon atoms, a linear, branched, or cyclic acyloxy group having 2 to 20 carbon atoms, a linear, branched, or cyclic alkoxyalkyl group having 2 to 20 carbon atoms, an alkylthioalkyl group having 2 to 20 carbon atoms, a halogen atom, a nitro group, a cyano group, a sulfinyl group, or a sulfonyl group. 3 is a single bond or a linear, branched or cyclic alkylene group having 1 to 10 carbon atoms, and an ether bond may be present between the carbon-carbon bond. o and p are each independently an integer of 0 to 4. h is an integer of 0 or 1. j is an integer of 0 to 5. k is an integer of 0 to 2.

[0137] A 3 Examples of alkylene groups represented by the formula (A14) include methylene, ethylene, propylene, butylene, pentylene, and hexylene, as well as structural isomers of carbon skeletons having a branched or cyclic structure. When the alkylene group contains an ether bond, if h in general formula (A14) is 1, the ether bond may be located at any position except between the carbon at the α-position and the carbon at the β-position relative to the ester oxygen. If h is 0, the atom bonded to the main chain may be an ether oxygen, and a second ether bond may be located at any position except between the carbon at the α-position and the carbon at the β-position relative to the ether oxygen. Note that the alkylene group preferably has 10 or fewer carbon atoms, since this allows for sufficient solubility in an alkaline developer.

[0138] R 15Preferred examples of the halogen atom include a chlorine atom, a bromine atom, and an iodine atom; preferred examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and structural isomers thereof, a cyclopentyl group, and a cyclohexyl group; and preferred examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, and structural isomers of the hydrocarbon moiety thereof, a cyclopentyloxy group, and a cyclohexyloxy group. Of these, methoxy and ethoxy groups are particularly useful. Furthermore, acyloxy groups can be easily introduced by a chemical modification method even after polymerization of the polymer, and can be advantageously used to finely adjust the solubility of the base polymer in an alkaline developer. Examples of the acyloxy group include methylcarbonyloxy, ethylcarbonyloxy, propylcarbonyloxy, butylcarbonyloxy, pentylcarbonyloxy, hexylcarbonyloxy, and their structural isomers, cyclopentylcarbonyloxy, cyclohexylcarbonyloxy, and benzoyloxy. When the carbon number is 20 or less, the effect of controlling and adjusting (mainly the effect of reducing) the solubility of the base resin in an alkaline developer can be appropriately achieved, and the occurrence of scum (development defects) can be suppressed. Among the preferred substituents mentioned above, particularly useful substituents that are easy to prepare as a monomer include a chlorine atom, a bromine atom, an iodine atom, a methyl group, an ethyl group, and a methoxy group.

[0139] In general formula (A14), k is an integer of 0 to 2, and represents a benzene skeleton when it is 0, a naphthalene skeleton when it is 1, and an anthracene skeleton when it is 2. When k is 0, j is preferably an integer of 0 to 3, and when k is 1 or 2, j is preferably an integer of 0 to 4.

[0140] h is 0 and A 3is a single bond, that is, the aromatic ring is directly bonded to the main chain of the polymer compound, that is, there is no linker, preferred examples of the repeating unit A14 include units derived from styrene, 4-chlorostyrene, 4-methylstyrene, 4-methoxystyrene, 4-bromostyrene, 4-acetoxystyrene, 2-hydroxypropylstyrene, 2-vinylnaphthalene, 3-vinylnaphthalene, etc.

[0141] Furthermore, when h is 1, that is, when the repeating unit A14 has an ester skeleton as a linker, preferred examples of the repeating unit A14 include, but are not limited to, those shown below.

[0142] [ka]

[0143] [ka]

[0144] When at least one of the repeating units A12 to A14 is used as a structural unit, the addition of a ring structure to the main chain provides the effect of improving resistance to electron beam irradiation during etching and pattern inspection, in addition to the etching resistance of the aromatic ring.

[0145] The repeating units A12 to A14 may be used singly or in combination of two or more. To obtain the effect of improving etching resistance, the content of the repeating units A12 to A14, based on all repeating units constituting the polymer compound of component (A), is preferably 2 mol % or more, and more preferably 5 mol %, and the upper limit is preferably 35 mol %, more preferably 20 mol %.

[0146] <Repeating units of (meth)acrylic acid esters with adhesive groups> The polymer compound of component (A) may contain a repeating unit of a (meth)acrylic acid ester having an adhesive group such as a lactone structure or a hydroxy group other than a phenolic hydroxy group, or other repeating unit, in order to fine-tune the properties of the resist film. Examples of the repeating unit of a (meth)acrylic acid ester having an adhesive group include units represented by the following formulas (b1) to (b3).

[0147] [ka] (In the formula, R A is the same as above. 1 is —O— or a methylene group. 2 is a hydrogen atom or a hydroxy group. 3 is a linear, branched or cyclic alkyl group having 1 to 4 carbon atoms, and n is an integer of 0 to 3.

[0148] These units do not exhibit acidity and can be used as auxiliary units for imparting adhesion to a substrate or for adjusting solubility.

[0149] When the polymer compound of component (A) does not contain repeating units A4 to A11, the content of repeating unit A3 in the polymer compound is preferably 25 to 95 mol %, more preferably 40 to 85 mol %. The content of repeating units A12 to A14 is preferably 0 to 30 mol %, more preferably 3 to 20 mol %. The content of repeating unit A1 or A2 is preferably 5 to 70 mol %, more preferably 5 to 60 mol %. The polymer compound may contain other repeating units in an amount of 0 to 30 mol %, preferably 0 to 20 mol %.

[0150] When the polymer compound of component (A) contains repeating units A4 to A11, the content of repeating unit A3 in the polymer compound is preferably 25 to 94.5 mol %, more preferably 36 to 85 mol %. The content of repeating units A12 to A14 is preferably 0 to 30 mol %, more preferably 3 to 20 mol %. The content of repeating unit A1 or A2 is preferably 5 to 70 mol %, more preferably 5 to 60 mol %. The total content of repeating units A1 or A2, A12, A13, and A14 is preferably 60 to 99.5 mol %. The content of repeating units A4 to A11 is preferably 0.5 to 20 mol %, more preferably 1 to 10 mol %. The polymer compound may contain other repeating units in an amount of 0 to 30 mol %, preferably 0 to 20 mol %.

[0151] When constructing a positive resist, the polymer compound of component (A) preferably contains a repeating unit represented by the following general formula (A1-1), a repeating unit represented by the following general formula (A3-1), and a repeating unit represented by the following general formula (A7-1).

[0152] [ka] (In the formula, R A , R B , Z 4 , R 29 , R 30 , R 31 , and b are the same as above. 50 is an acid labile group.

[0153] Furthermore, when constructing a positive resist, the polymer compound of component (A) is preferably a polymer compound that contains a repeating unit A1 represented by general formula (A1) and a repeating unit A3 represented by general formula (A3), but does not contain any of the repeating units A4 to A11 represented by general formulas (A4) to (A11).

[0154] Furthermore, when constructing a negative resist, the polymer compound of component (A) preferably contains a repeating unit represented by the following general formula (A2-1) or the following general formula (A2-2), a repeating unit represented by the following general formula (A3-1), and a repeating unit represented by the following general formula (A5-1).

[0155] [ka] (In the formula, R A , R B , Z 2 , R 23 , R 24 , R 25 , Rx, Ry, b, and g are the same as above.)

[0156] Furthermore, when constructing a negative resist, the polymer compound of component (A) is preferably a polymer compound that contains a repeating unit A2 represented by general formula (A2) and a repeating unit A3 represented by general formula (A3), but does not contain any of the repeating units A4 to A11 represented by general formulas (A4) to (A11).

[0157] The polymer compound of component (A) may be a combination of one that does not contain repeating units A4 to A11 and one that does contain repeating units A4 to A11. In this case, the amount of the polymer that does not contain repeating units A4 to A11 is preferably 2 to 5,000 parts by mass, and more preferably 10 to 1,000 parts by mass, per 100 parts by mass of the polymer that contains repeating units A4 to A11.

[0158] Furthermore, when the polymeric compound of component (A) used in the present invention is a polymer of two or more polymerizable monomers, the total amount of residual dimer to hexamer oligomers contained in all the polymerizable monomers used is preferably 5000 ppm or less, more preferably 3000 ppm or less, and it is particularly preferable to control the amount of dimer to tetramer oligomers. If the total amount of residual dimer to hexamer oligomers contained in all the polymerizable monomers is 5000 ppm or less, it is possible to more reliably prevent the occurrence of development residue defects, which can lead to a decrease in yield, which is important for the semiconductor manufacturing process.

[0159] Of all the repeating units constituting the polymer compound of component (A), repeating units A1 to A14 preferably account for 70 mol % or more, and more preferably 80 mol % or more, thereby ensuring that the properties required for the chemically amplified resist composition of the present invention, particularly for use in producing photomask substrates, are obtained.

[0160] When a positive resist composition is used to fabricate a photomask, the coating thickness for the most advanced generation is 150 nm or less, preferably 100 nm or less. The base polymer constituting the positive resist composition is designed to have a dissolution rate in an alkaline developer of 8 nm / min or less, preferably 6 nm / min or less, and more preferably 5 nm / min or less. In the most advanced generation, when the coating film on the substrate is in the thin region (100 nm or less), the impact of pattern film loss due to alkaline development becomes significant. If the alkaline dissolution rate of the polymer is greater than 8 nm / min, the pattern collapses, making it impossible to form a fine pattern. This is particularly noticeable in the fabrication of photomasks, which require defect-free operation, since the development process tends to be intense. In this invention, the dissolution rate of the base polymer in an alkaline developer is calculated from the amount of film loss when a polymer solution is spin-coated on a 200 mm (8 inch) diameter silicon wafer, baked at 100°C for 90 seconds, and then developed for 100 seconds in a 2.38% TMAH aqueous solution.

[0161] Furthermore, when a negative resist composition is used to produce a photomask, the coating film thickness for the most advanced generation is 150 nm or less, preferably 100 nm or less. The dissolution rate of the base polymer constituting the negative resist composition in an alkaline developer (a 2.38% by mass aqueous solution of tetramethylammonium hydroxide (TMAH)) is preferably 80 nm / sec or less, more preferably 50 nm / sec or less, in order to form a fine pattern, which is generally achieved using a strong development process to minimize defects caused by resist residues. Furthermore, when using the negative resist composition of the present invention in an EUV exposure process, for example, when producing an LSI chip from a wafer, the coating film thickness is often 100 nm or less because it is necessary to pattern fine lines of 50 nm or less. Because the film is thin, pattern degradation due to development is anticipated. Therefore, the dissolution rate of the polymer used is preferably 80 nm / sec or less, more preferably 50 nm / sec or less. On the other hand, in the KrF exposure process, although it depends on the purpose, the coating thickness is often as thick as 200 nm or more, and in such cases it is preferable to design the dissolution rate of the polymer used to be 90 nm / sec or more.

[0162] The polymer compound of component (A) can be synthesized by copolymerizing each monomer, optionally protected with a protecting group, using a known method, followed by a deprotection reaction as needed. The copolymerization reaction is not particularly limited, but is preferably radical polymerization or anionic polymerization. For these methods, reference can be made to WO 2006 / 121096, JP 2008-102383 A, JP 2008-304590 A, and JP 2004-115630 A.

[0163] The polymer compound of component (A) preferably has a weight-average molecular weight (Mw) of 1,000 to 50,000, more preferably 2,000 to 25,000. If Mw is 1,000 or more, there is no risk of the conventionally known phenomenon of pattern heads becoming rounded, reducing resolution and LER degradation. On the other hand, if Mw is 50,000 or less, there is no risk of LER increasing, particularly when forming patterns with line widths of 100 nm or less. In the present invention, Mw is a value measured using gel permeation chromatography (GPC) in terms of polystyrene.

[0164] The polymer compound of component (A) preferably has a narrow molecular weight distribution (Mw / Mn) of 1.0 to 2.5, particularly 1.0 to 2.2, such that foreign matter does not appear on the pattern after development, and the pattern shape does not deteriorate.

[0165] [(B) Acid generator] The chemically amplified resist composition of the present invention may contain (B) an acid generator, particularly a photoacid generator, in order to function as a chemically amplified resist composition. The photoacid generator is not particularly limited as long as it is a compound that generates an acid upon exposure to high-energy rays. Suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, and oxime-O-sulfonate-type acid generators. These may be used alone or in combination of two or more.

[0166] Specific examples of photoacid generators include nonafluorobutanesulfonate, the partially fluorinated sulfonates described in JP-A-2012-189977, paragraphs

[0247] to

[0251] , the partially fluorinated sulfonates described in JP-A-2013-101271, paragraphs

[0261] to

[0265] , the partially fluorinated sulfonates described in JP-A-2008-111103, paragraphs

[0122] to

[0142] , and the partially fluorinated sulfonates described in JP-A-2010-215608, paragraphs

[0080] to

[0081] . Among these examples, arylsulfonate- or alkane sulfonate-type photoacid generators are preferred because they generate an acid of sufficient strength to deprotect the acid-labile group in the repeating unit represented by formula (A1). Preferred photoacid generators include compounds having a sulfonium anion with the structure shown below. Examples of the counter cation include those mentioned above as specific examples of the sulfonium cation in the general formulae (A5) to (A7).

[0167] [ka]

[0168] [ka]

[0169] [ka]

[0170] [ka]

[0171] [ka]

[0172] [ka]

[0173] [ka]

[0174] The content of the (B) acid generator, particularly the photoacid generator, is preferably 1 to 30 parts by mass, more preferably 2 to 20 parts by mass, per 80 parts by mass of the polymer compound of component (A). The preferred anion has an acid strength of pKa of -1.5 or higher. The pKa value was calculated using the pKa DB in ACD / Chemsketch ver. 9.04 software from Advanced Chemistry Development, Inc.

[0175] [(C) Basic compound (quencher)] The chemically amplified resist composition of the present invention preferably contains a basic compound. Suitable basic compounds include conventional basic compounds.

[0176] Examples of conventional basic compounds include primary, secondary, and tertiary aliphatic amines, mixed amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxyl group, nitrogen-containing compounds having a sulfonyl group, nitrogen-containing compounds having a hydroxyl group, nitrogen-containing compounds having a hydroxyphenyl group, alcoholic nitrogen-containing compounds, amides, imides, and carbamates. Particularly preferred are the primary, secondary, and tertiary amine compounds described in paragraphs

[0146] to

[0164] of JP 2008-111103 A, particularly amine compounds having a hydroxyl group, an ether bond, an ester bond, a lactone ring, a cyano group, or a sulfonate ester bond, and compounds having a carbamate group described in Japanese Patent No. 3790649 A. Preferred examples include tris[2-(methoxymethoxy)ethyl]amine, tris[2-(methoxymethoxy)ethyl]amine N-oxide, dibutylaminobenzoic acid, morpholine derivatives, and imidazole derivatives. By adding such a basic compound, for example, it is possible to further suppress the diffusion rate of the acid in the resist film and correct the shape.

[0177] Further, examples of the quencher include onium salts such as sulfonium salts, iodonium salts, and ammonium salts of carboxylic acids not fluorinated at the α-position, as described in JP-A-2008-158339. Sulfonic acids, imide acids, or methide acids fluorinated at the α-position are necessary for deprotecting acid labile groups, and salt exchange with onium salts not fluorinated at the α-position releases carboxylic acids not fluorinated at the α-position. Carboxylic acids not fluorinated at the α-position hardly undergo deprotection reactions, and therefore function as quenchers.

[0178] Examples of onium salts of carboxylic acids that are not fluorinated at the α-position include compounds represented by the following general formula (H1).

[0179] [ka]

[0180] In general formula (H1), R 101 represents a hydrocarbyl group having 1 to 40 carbon atoms which may contain a hydrogen atom or a heteroatom, but excludes those in which the hydrogen atom bonded to the carbon atom at the α-position of the sulfo group is substituted with a fluorine atom or a fluoroalkyl group.

[0181] The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, and tricyclo[5.2.1.0]. 2,6cyclic saturated hydrocarbyl groups such as a ]decanyl group, adamantyl group, and adamantylmethyl group; alkenyl groups such as a vinyl group, allyl group, propenyl group, butenyl group, and hexenyl group; cyclic unsaturated aliphatic hydrocarbyl groups such as a cyclohexenyl group; aryl groups such as a phenyl group, a naphthyl group, an alkylphenyl group (2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-ethylphenyl group, 4-tert-butylphenyl group, 4-n-butylphenyl group, etc.), a dialkylphenyl group (2,4-dimethylphenyl group, etc.), a trialkylphenyl group (2,4,6-triisopropylphenyl group, etc.), an alkylnaphthyl group (methylnaphthyl group, ethylnaphthyl group, etc.), and a dialkylnaphthyl group (dimethylnaphthyl group, diethylnaphthyl group, etc.); and aralkyl groups such as a benzyl group, a 1-phenylethyl group, and a 2-phenylethyl group.

[0182] Furthermore, some of the hydrogen atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the carbon atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, and nitrogen atoms, resulting in the group containing a hydroxy group, a cyano group, a carbonyl group, an ether bond, a thioether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, or the like. Examples of the hydrocarbyl group containing a heteroatom include heteroaryl groups such as a thienyl group; alkoxyphenyl groups such as a 4-hydroxyphenyl group, a 4-methoxyphenyl group, a 3-methoxyphenyl group, a 2-methoxyphenyl group, a 4-ethoxyphenyl group, a 4-tert-butoxyphenyl group, and a 3-tert-butoxyphenyl group; alkoxynaphthyl groups such as a methoxynaphthyl group, an ethoxynaphthyl group, an n-propoxynaphthyl group, and an n-butoxynaphthyl group; dialkoxynaphthyl groups such as a dimethoxynaphthyl group and a diethoxynaphthyl group; and aryloxoalkyl groups such as a 2-aryl-2-oxoethyl group, a 2-(1-naphthyl)-2-oxoethyl group, and a 2-(2-naphthyl)-2-oxoethyl group.

[0183] In general formula (H1), Mq + is an onium cation. The onium cation is preferably a sulfonium cation, an iodonium cation, or an ammonium cation, and more preferably a sulfonium cation or an iodonium cation. Preferred examples include the specific examples of the sulfonium cations in the above general formulas (A5) to (A7). Specific examples of the anion structure of the salt represented by the above general formula (H1) are listed below, but the present invention is not limited to these.

[0184] [ka]

[0185] [ka]

[0186] As the quencher, a sulfonium salt of an iodinated benzene ring-containing carboxylic acid represented by the following general formula (H2) can also be suitably used.

[0187] [ka]

[0188] In general formula (H2), R 201 represents a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an amino group, a nitro group, a cyano group, or a saturated hydrocarbyl group having 1 to 6 carbon atoms, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms, or a saturated hydrocarbylsulfonyloxy group having 1 to 4 carbon atoms, in which some or all of the hydrogen atoms may be substituted with halogen atoms, or -NR 201A -C(=O)-R 201B or -NR 201A -C(=O)-OR 201B R 201A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 201Bis a saturated hydrocarbyl group having 1 to 6 carbon atoms or an unsaturated aliphatic hydrocarbyl group having 2 to 8 carbon atoms.

[0189] In the general formula (H2), x is an integer of 1 to 5. y is an integer of 0 to 3. z is an integer of 1 to 3. L 1 is a single bond or a (z+1)-valent linking group having 1 to 20 carbon atoms, and may contain at least one selected from an ether bond, a carbonyl group, an ester bond, an amide bond, a sultone ring, a lactam ring, a carbonate group, a halogen atom, a hydroxy group, and a carboxy group. The saturated hydrocarbyl group, saturated hydrocarbyloxy group, saturated hydrocarbylcarbonyloxy group, and saturated hydrocarbylsulfonyloxy group may be linear, branched, or cyclic. When y and / or z is 2 or more, each R 201 may be the same or different from each other.

[0190] In general formula (H2), R 202 , R 203 and R 204 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, and an aralkyl group having 7 to 20 carbon atoms. Some or all of the hydrogen atoms in these groups may be substituted with a hydroxy group, a carboxy group, a halogen atom, an oxo group, a cyano group, a nitro group, a sultone group, a sulfone group, or a sulfonium salt-containing group. Some of the carbon atoms in these groups may be substituted with an ether bond, an ester bond, a carbonyl group, an amide bond, a carbonate group, or a sulfonate ester bond. Furthermore, R 202 and R 203 may be bonded to each other to form a ring together with the sulfur atom to which they are attached.

[0191] Specific examples of the compound represented by general formula (H2) include those described in JP 2017-219836 A. These compounds also have high absorption, a high sensitizing effect, and a high acid diffusion control effect.

[0192] Furthermore, the quencher may also be a nitrogen-containing carboxylate compound described in JP-A-2016-200805. Specific examples include, but are not limited to, the compounds shown below.

[0193] [ka]

[0194] [ka]

[0195] [ka]

[0196] [ka]

[0197] [ka]

[0198] Furthermore, a weak acid betaine type compound can also be used as the quencher. Specific examples thereof include, but are not limited to, the following:

[0199] [ka]

[0200] Further examples of the quencher include the polymer-type quencher described in JP 2008-239918 A. This quencher enhances the rectangularity of the resist after patterning by orienting on the surface of the resist film after application of the resist composition. The polymer-type quencher also has the effect of preventing film loss and rounding of the pattern top when a protective film for immersion lithography is applied.

[0201] When the chemically amplified resist composition of the present invention contains a quencher, the content thereof is preferably 0 to 50 parts by mass, more preferably 0.1 to 40 parts by mass, relative to 80 parts by mass of the base polymer (e.g., the polymer compound (A)). The quenchers may be used singly or in combination of two or more.

[0202] [(D) Fluorine-containing polymer] The chemically amplified resist composition of the present invention may contain, as component (D), a fluorine-containing polymer containing at least one repeating unit selected from the group consisting of a repeating unit represented by the following general formula (D1) (hereinafter also referred to as repeating unit D1) and repeating units represented by the following general formulas (D2), (D3), (D4), and (D5) (hereinafter also referred to as repeating units D2, D3, D4, and D5, respectively) for the purposes of achieving high contrast, shielding against acid chemical flare upon high-energy radiation exposure, and preventing acid mixing from the antistatic film during the process of applying an antistatic film material to the resist, thereby suppressing unexpected and unnecessary pattern degradation. The fluorine-containing polymer also has a surfactant function, which prevents insoluble matter from reattaching to the substrate during the development process, thereby effectively reducing development defects.

[0203] [ka]

[0204] In the formula, R B are each independently a hydrogen atom or a methyl group. C are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.41 R is a hydrogen atom or a linear or branched monovalent hydrocarbon group having 1 to 5 carbon atoms, which may have a heteroatom interposed between its carbon-carbon bond. 42 R is a linear or branched monovalent hydrocarbon group having 1 to 5 carbon atoms, which may have a heteroatom between its carbon-carbon bonds. 43a , R 43b , R 45a and R 45b are each independently a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms. 44 , R 46 , R 47 and R 48 are each independently a hydrogen atom, a linear, branched, or cyclic monovalent hydrocarbon group or fluorinated monovalent hydrocarbon group having 1 to 15 carbon atoms, or an acid labile group; R 44 , R 46 , R 47 and R 48 When the group is a monovalent hydrocarbon group or a fluorinated monovalent hydrocarbon group, an ether group or a carbonyl group may be present between the carbon-carbon bond. x is an integer of 1 to 3. y is an integer that satisfies 0≦y≦5+2z−x. z is 0 or 1. m is an integer of 1 to 3. X 1 is a single bond, —C(═O)—O—, or —C(═O)—NH—. X 2 is a linear, branched or cyclic hydrocarbon group or fluorinated hydrocarbon group having 1 to 20 carbon atoms and a valence of (m+1).

[0205] R 41 , R 42 , R 44 , R 46 , R 47 , R 48 Examples of the monovalent hydrocarbon group include alkyl groups, alkenyl groups, and alkynyl groups, with alkyl groups being preferred. Examples of the alkyl group include methyl groups, ethyl groups, n-propyl groups, isopropyl groups, n-butyl groups, isobutyl groups, sec-butyl groups, and n-pentyl groups. Furthermore, a heteroatom-containing group such as an oxygen atom, sulfur atom, or nitrogen atom may be present between the carbon-carbon bonds of these groups.

[0206] In general formula (D1), -OR 41 is preferably a hydrophilic group. In this case, R 41 As the alkyl group, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms and an oxygen atom intervening between the carbon-carbon bonds, and the like are preferred.

[0207] Examples of the repeating unit D1 include, but are not limited to, those shown below. B is the same as above.

[0208] [ka]

[0209] [ka]

[0210] In the repeating unit D1, X 1 is preferably -C(=O)-O- or -C(=O)-NH-. B is preferably a methyl group. 1 The presence of a carbonyl group in R improves the acid trapping ability of the antistatic film. B When the methyl group is used, the polymer becomes more rigid with a higher glass transition temperature (Tg), which suppresses acid diffusion, resulting in good stability of the resist film over time and preventing degradation of resolution and pattern shape.

[0211] In general formulas (D2) and (D3), R 43a , R 43b , R 45a and R 45bExamples of the alkyl group represented by the formula (I) include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a cyclopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a cyclobutyl group, an n-pentyl group, a cyclopentyl group, an n-hexyl group, a cyclohexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an adamantyl group, a norbornyl group, etc. Among these, a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms is preferred.

[0212] In general formulas (D2) to (D5), R 44 , R 46 , R 47 and R 48 Examples of the monovalent hydrocarbon group represented by the formula (I) include alkyl groups, alkenyl groups, and alkynyl groups, with alkyl groups being preferred. Examples of the alkyl group include those mentioned above, as well as n-undecyl groups, n-dodecyl groups, tridecyl groups, tetradecyl groups, and pentadecyl groups. Examples of the fluorinated monovalent hydrocarbon group include groups in which some or all of the hydrogen atoms bonded to carbon atoms of the aforementioned monovalent hydrocarbon groups have been substituted with fluorine atoms.

[0213] X 2 Examples of the linear, branched, or cyclic hydrocarbon group or fluorinated hydrocarbon group having 1 to 20 carbon atoms and a valence of (m+1) include groups in which m hydrogen atoms have been further removed from the aforementioned monovalent hydrocarbon group or fluorinated monovalent hydrocarbon group.

[0214] Specific examples of the repeating units D2 to D5 include, but are not limited to, the following: C is the same as above.

[0215] [ka]

[0216] [ka]

[0217] The content of the repeating unit D1 is preferably 5 to 85 mol %, more preferably 15 to 80 mol %, of all repeating units in the fluorine-containing polymer (D). The repeating units D2 to D5 may be used singly or in combination of two or more, and is preferably 15 to 95 mol %, more preferably 20 to 85 mol %, of all repeating units in the fluorine-containing polymer (D).

[0218] The (D) fluorine-containing polymer may contain repeating units other than the repeating units described above. Examples of such repeating units include those described in paragraphs

[0046] to

[0078] of JP 2014-177407 A. When the (D) fluorine-containing polymer contains other repeating units, the content of such other repeating units is preferably 50 mol % or less of all repeating units.

[0219] The (D) fluorine-containing polymer can be synthesized by copolymerizing each monomer, optionally protected with a protecting group, using a known method, followed by a deprotection reaction as needed. The copolymerization reaction is not particularly limited, but is preferably radical polymerization or anionic polymerization. For these methods, reference can be made to JP-A-2004-115630.

[0220] The weight-average molecular weight (Mw) of the (D) fluorine-containing polymer is preferably 2,000 to 50,000, more preferably 3,000 to 20,000. If Mw is 2,000 or more, acid diffusion can be prevented and resolution and stability over time can be sufficiently maintained. If Mw is 50,000 or less, solubility in solvents is sufficiently high and coating defects do not occur. Furthermore, the (D) fluorine-containing polymer preferably has a molecular weight distribution (Mw / Mn) of 1.0 to 2.2, more preferably 1.0 to 1.7.

[0221] The content of the (D) fluorine-containing polymer is preferably 0.01 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, and even more preferably 0.5 to 10 parts by mass, relative to 80 parts by mass of the base polymer (e.g., the (A) polymer compound). The content is not limited to the above, and the fluorine-containing polymers described in, for example, paragraphs

[0027] to

[0041] of Japanese Patent Publication No. 4466881 can also be used.

[0222] [(E) Organic solvent] The chemically amplified resist composition of the present invention may contain an organic solvent as component (E). There are no particular restrictions on the organic solvent, so long as it is capable of dissolving the individual components contained in the composition.

[0223] Examples of such organic solvents include ketones such as cyclohexanone and methyl-2-n-pentyl ketone; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and diacetone alcohol; propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, and ethylene glycol monoethyl ether, as described in paragraphs

[0144] and

[0145] of JP-A-2008-111103. Examples of suitable solvents include ethers such as propylene glycol dimethyl ether and diethylene glycol dimethyl ether; esters such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol monotert-butyl ether acetate; lactones such as γ-butyrolactone; and mixed solvents thereof. When an acetal-based acid labile group is used, a high-boiling alcohol solvent, specifically, diethylene glycol, propylene glycol, glycerin, 1,4-butanediol, 1,3-butanediol, or the like, can be added to accelerate the deprotection reaction of the acetal.

[0224] Among these organic solvents, 1-ethoxy-2-propanol, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, cyclohexanone, ethyl lactate, γ-butyrolactone, and mixed solvents thereof are preferred.

[0225] The content of the (E) organic solvent is preferably 200 to 10,000 parts by mass, and more preferably 400 to 5,000 parts by mass, per 100 parts by mass of the base polymer (for example, the (A) polymer compound). The (E) organic solvent may be used alone or in combination of two or more.

[0226] [(F) Crosslinking agent] When the chemically amplified resist composition of the present invention is a negative resist composition, and the polymeric compound of component (A) does not contain a repeating unit represented by general formula (A2), it is preferable to incorporate a crosslinking agent. On the other hand, when the polymeric compound of component (A) contains a repeating unit represented by general formula (A2), it is not necessary to incorporate a crosslinking agent.

[0227] Specific examples of crosslinking agents that can be used in the present invention include melamine compounds, guanamine compounds, glycoluril compounds, urea compounds, epoxy compounds, isocyanate compounds, azide compounds, and compounds containing double bonds such as alkenyl ether groups, all of which are substituted with at least one group selected from a methylol group, an alkoxymethyl group, and an acyloxymethyl group. These may be used as additives or may be introduced as pendant groups into polymer side chains. Compounds containing hydroxy groups may also be used as crosslinking agents.

[0228] Among the crosslinking agents, examples of the epoxy compounds include tris(2,3-epoxypropyl)isocyanurate, trimethylolmethane triglycidyl ether, trimethylolpropane triglycidyl ether, and triethylolethane triglycidyl ether.

[0229] Examples of the melamine compound include compounds in which 1 to 6 methylol groups are methoxymethylated, such as hexamethylol melamine, hexamethoxymethyl melamine, and hexamethylol melamine, or mixtures thereof; and compounds in which 1 to 6 methylol groups are acyloxymethylated, such as hexamethoxyethyl melamine, hexaacyloxymethyl melamine, and hexamethylol melamine, or mixtures thereof.

[0230] Examples of the guanamine compound include compounds in which 1 to 4 methylol groups are methoxymethylated, such as tetramethylolguanamine, tetramethoxymethylguanamine, and tetramethylolguanamine, and mixtures thereof; and compounds in which 1 to 4 methylol groups are acyloxymethylated, such as tetramethoxyethylguanamine, tetraacyloxyguanamine, and tetramethylolguanamine, and mixtures thereof.

[0231] Examples of glycoluril compounds include compounds in which 1 to 4 methylol groups are methoxymethylated, such as tetramethylol glycoluril, tetramethoxyglycoluril, tetramethoxymethyl glycoluril, and tetramethylol glycoluril, or mixtures thereof; and compounds in which 1 to 4 methylol groups are acyloxymethylated in tetramethylol glycoluril, or mixtures thereof.

[0232] Examples of the urea compound include tetramethylol urea, tetramethoxymethyl urea, compounds in which 1 to 4 methylol groups are methoxymethylated, such as tetramethylol urea, or mixtures thereof, and tetramethoxyethyl urea.

[0233] Examples of the isocyanate compound include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and cyclohexane diisocyanate.

[0234] Examples of the azide compound include 1,1'-biphenyl-4,4'-bisazide, 4,4'-methylidenebisazide, and 4,4'-oxybisazide.

[0235] Examples of compounds containing an alkenyl ether group include ethylene glycol divinyl ether, triethylene glycol divinyl ether, 1,2-propanediol divinyl ether, 1,4-butanediol divinyl ether, tetramethylene glycol divinyl ether, neopentyl glycol divinyl ether, trimethylolpropane trivinyl ether, hexanediol divinyl ether, 1,4-cyclohexanediol divinyl ether, pentaerythritol trivinyl ether, pentaerythritol tetravinyl ether, sorbitol tetravinyl ether, sorbitol pentavinyl ether, and trimethylolpropane trivinyl ether.

[0236] The amount of the crosslinking agent is preferably 0.5 to 50 parts by mass, more preferably 5 to 30 parts by mass, relative to 80 parts by mass of the polymer compound of component (A). Within this range, there is little risk of patterns being connected together and resolution decreasing. The crosslinking agents can be used alone or in combination of two or more.

[0237] [(G) Surfactant] A commonly used surfactant may be added to the chemically amplified resist composition of the present invention to improve its coatability onto a substrate. Many surfactants are known, including those described in JP-A-2004-115630, and can be selected with reference to these. The surfactant content is preferably 0 to 5 parts by weight per 80 parts by weight of the polymer compound of component (A). However, if component (D) is included in the resist, component (D) also functions as a surfactant, so it need not be added to the resist.

[0238] The positive resist composition is designed to have a dissolution rate of the resist coating film in an alkaline developer of 10 nm / min or less, preferably 8 nm / min or less, and more preferably 6 nm / min or less. When the coating film on the substrate is thin (100 nm or less), the impact of pattern film loss due to alkaline development becomes significant. If the alkaline dissolution rate of the positive resist composition exceeds 10 nm / min, the pattern collapses, making it impossible to form a fine pattern. This is particularly noticeable in the production of photomasks, which require a defect-free environment, since the development process tends to be intense. The dissolution rate in an alkaline developer in this invention is a value calculated from the amount of film loss when a 6-inch silicon wafer is spin-coated with the positive resist composition of the invention, baked at 110°C for 240 seconds, and then developed for 80 seconds in a 2.38% TMAH aqueous solution.

[0239] Furthermore, in the design of negative resist compositions, taking into account development residues after alkaline development in advanced lithography, the dissolution rate of the resist coating film in an alkaline developer is 0.5 nm / sec or higher, preferably 1 nm / sec or higher. If the alkaline dissolution rate of a negative resist composition is 0.5 nm / sec or higher, there is even less risk of development residues being generated after alkaline development, which could lead to defects. In the present invention, the dissolution rate in an alkaline developer is a value calculated from the amount of film loss when a 6-inch silicon wafer is spin-coated with the negative resist composition of the present invention, baked at 110°C for 240 seconds, and then developed for 60 seconds in a 2.38% TMAH aqueous solution.

[0240] [Method of manufacturing polymer compounds] The present invention also provides a method for producing a polymeric compound that contains one or more repeating units and is used in a chemically amplified resist composition, by polymerizing at least one polymerizable monomer having a residual oligomer content of 2 to 6 monomers of 1000 ppm or less to obtain the polymeric compound.

[0241] In this case, it is preferable that at least one of the repeating units obtained from the polymerizable monomers having a residual oligomer content of 2 to 6 monomers of 1000 ppm or less is the repeating unit A1 represented by the general formula (A1) or the repeating unit A2 represented by the general formula (A2).

[0242] In this manner, rather than purifying at the polymer stage, a material in which the content of oligomer components is suppressed at the pre-polymerization monomer stage can be used to produce a polymer compound that can be used in a chemically amplified resist composition that satisfies good resolution, pattern shape, and line edge roughness, while suppressing development residue defects that cause mask defects.

[0243] [Method for forming resist pattern] The present invention also provides a method for forming a resist pattern, comprising the steps of: (1) forming a resist film on a substrate using the above-described chemically amplified resist composition; (2) irradiating the resist film with a pattern using high-energy rays; and (3) developing the resist film that has been irradiated with the pattern using an alkaline developer.

[0244] The substrate may be, for example, a substrate for manufacturing integrated circuits (Si, SiO, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflective coating, etc.), or a substrate for manufacturing mask circuits (Cr, CrO, CrON, MoSi2, Si, SiO, SiO2, SiON, SiONC, CoTa, NiTa, TaBN, SnO2, etc.). The chemically amplified resist composition of the present invention is applied to the substrate by a method such as spin coating to a film thickness of, for example, 0.03 to 2 μm, and the composition is then pre-baked on a hot plate preferably at 60 to 150°C for 1 to 20 minutes, more preferably at 80 to 140°C for 1 to 10 minutes, to form a resist film.

[0245] Next, the resist film is exposed to high-energy radiation to form a pattern. Examples of the high-energy radiation include ultraviolet radiation, far ultraviolet radiation, excimer laser light (KrF, ArF, etc.), extreme ultraviolet radiation (EUV), X-rays, gamma rays, synchrotron radiation, and electron beams. In the present invention, exposure using EUV or electron beams (EB) is preferred.

[0246] When ultraviolet rays, far ultraviolet rays, excimer laser light, EUV, X-rays, gamma rays, or synchrotron radiation is used as the high-energy rays, a mask for forming a desired pattern is used, and the exposure dose is preferably 1 to 500 mJ / cm. 2 , more preferably 10 to 400 mJ / cm 2 When EB is used, the exposure dose is preferably 1 to 500 μC / cm 2 directly to form the desired pattern. 2 , more preferably 10 to 400 μC / cm 2 Irradiate so that

[0247] The exposure can be performed by a conventional exposure method, or in some cases by an immersion method in which the space between the mask and the resist is immersed in liquid. In this case, a water-insoluble protective film can be used.

[0248] Next, post-exposure baking (PEB) is carried out on a hot plate, preferably at 60 to 150° C. for 1 to 20 minutes, more preferably at 80 to 140° C. for 1 to 10 minutes.

[0249] Thereafter, the substrate is developed using a developer such as an aqueous alkaline solution of 0.1 to 5 mass %, preferably 2 to 3 mass %, TMAH, etc., by a conventional method such as dipping, puddling, or spraying for preferably 0.1 to 3 minutes, more preferably 0.5 to 2 minutes, to form a desired pattern on the substrate.

[0250] It is also preferable that the outermost surface of the substrate is made of a material containing at least one of chromium, silicon, tantalum, molybdenum, cobalt, nickel, tungsten, and tin.

[0251] The chemically amplified resist composition of the present invention is particularly useful because it can suppress development defects that can lead to mask defects. Furthermore, the chemically amplified resist composition of the present invention can effectively reduce development defects even if there are differences in adhesion depending on the type of substrate. Examples of such substrates include substrates having a sputtering film formed on the outermost surface by sputtering metal chromium or a chromium compound containing one or more light elements selected from oxygen, nitrogen, and carbon, SiO , SiO x , a tantalum compound, a molybdenum compound, a cobalt compound, a nickel compound, a tungsten compound, or a tin compound in the outermost layer. The chemically amplified resist composition of the present invention is particularly useful for pattern formation using a photomask blank as the substrate. In this case, the photomask blank may be either a transmissive or reflective type.

[0252] With the method for forming a resist pattern of the present invention, even when a substrate (e.g., a photomask blank) is used whose outermost surface is made of a material that is likely to affect the shape of the resist pattern, such as a material containing chromium, silicon, or tantalum, a pattern with high resolution and in which the effects of development defects are suppressed can be obtained.

[0253] [Photomask blank] Therefore, the present invention provides a photomask blank coated with the above-mentioned chemically amplified resist composition. The chemically amplified resist composition of the present invention is particularly useful for pattern formation using a photomask blank as a substrate. [Example]

[0254] The present invention will be specifically explained below with reference to synthesis examples, working examples, and comparative examples, but the present invention is not limited by these descriptions. In the following examples, Me represents a methyl group. The copolymer composition ratio is a molar ratio, and the weight average molecular weight (Mw) represents the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC). The oligomer values ​​are calculated concentrations obtained in terms of each monomer measured by LC-MS (apparatus name: Thermo Fisher SCIENTIFIC / Vanquish (LC system), Q-Exactive (MS)).

[0255] [1] Monomer synthesis [Synthesis Example 1] Synthesis of Monomer (1) and Monomer (2) A 3 L four-neck flask was charged with 42.1 g of magnesium and 50 mL of THF under a nitrogen atmosphere. A solution of 200 g of 4-chlorostyrene in 200 mL of THF was added dropwise at room temperature over 1 hour. The mixture was then heated to 80°C and stirred for 3 hours to prepare a Grignard reagent. The resulting Grignard reagent was cooled in an ice bath, and a solution of 100.6 g of acetone in 200 mL of THF was added dropwise over 1 hour. After overnight stirring, the reaction was quenched by adding 1,000 g of 15% by weight aqueous ammonium chloride solution. A typical aqueous work-up was then performed. 0.02 g of 4-tert-butylcatechol was then added to the crude product, which was then purified by vacuum distillation at 90°C and 20 Pa to obtain 145.2 g of the target monomer (1) with the following structure (62% yield). The dimer to hexamer oligomer content was 1700 ppm. [ka]

[0256] After aqueous post-treatment, 0.2 g of 4-tert-butylcatechol was added and purified by vacuum distillation at a bath temperature of 70°C and 5 Pa. The same procedure as for the synthesis of Monomer (1) was used to obtain 140.5 g of the target Monomer (2) (yield 60%). The content of dimer to hexamer oligomers was 90 ppm.

[0257] [Synthesis Example 2] Synthesis of Monomer (3) and Monomer (4) A 3L four-neck flask was charged with 27.8g of magnesium and 50mL of THF under a nitrogen atmosphere. A solution of 200g of 1-chloro-4-[(1-methylcyclopentyl)oxy]benzene in 200mL of THF was added dropwise at room temperature over 1 hour. The mixture was then heated to 80°C and stirred for 3 hours to prepare the Grignard reagent. The resulting Grignard reagent was cooled in an ice bath, and 2.5g of dichloro(1,3-bis(diphenylphosphino)propane)nickel was added. After aging for 30 minutes, a solution of 151.2g of vinyl bromide in 200mL of THF was added dropwise over 1 hour. After stirring overnight, the reaction was quenched by the dropwise addition of 1,000g of 15% by weight aqueous ammonium chloride solution. A typical aqueous work-up was performed. Thereafter, 0.02 g of 4-tert-butylcatechol was added to the crude product, and the mixture was purified by vacuum distillation at a bath temperature of 100°C and 20 Pa to obtain 111.3 g of the target monomer (3) having the following structure (yield: 58%). The content of dimer to hexamer oligomers was 1600 ppm. [ka]

[0258] After aqueous post-treatment, 0.2 g of 4-tert-butylcatechol was added and purified by vacuum distillation at a bath temperature of 80°C and 5 Pa. The same procedure as for the synthesis of monomer (3) was used to obtain 105.6 g of the target monomer (4) (yield: 55%). The concentration of dimer to hexamer oligomers was 110 ppm.

[0259] [Synthesis Example 3] Synthesis of Monomer (5) and Monomer (6) 200 g of 4-acetoxystyrene (Tokyo Chemical Industry Co., Ltd.) was dissolved in 800 g of ethyl acetate, and a solution of 73.5 g of sodium methoxide in 200 mL of methanol was added dropwise over 1 hour under ice cooling. After stirring for 3 hours, 800 g of water was added dropwise to quench the reaction. A typical aqueous work-up was then performed. 0.02 g of 4-tert-butylcatechol was then added to the crude product, and the mixture was concentrated at a bath temperature of 50°C to obtain 121.5 g of the target monomer (5) with the following structure (yield: 82%). The concentration of dimer to hexamer oligomers was 1650 ppm. [ka]

[0260] After aqueous workup, 0.2 g of 4-tert-butylcatechol was added and the mixture was concentrated at a bath temperature of 35°C. The same procedure as for the synthesis of monomer (5) was used to obtain 118.5 g of the target monomer (6) (yield 80%). The concentration of dimer to hexamer oligomers was 160 ppm.

[0261] [Synthesis Example 4] Synthesis of Monomer (7) and Monomer (8) 49.0 g (0.1 mol) of triphenylsulfonium 1,1,3,3,3-pentafluoro-2-hydroxypropane-1-sulfonate was dissolved in 200 g of dichloromethane, and 10.1 g (0.10 mol) of triethylamine and 2.4 g (0.2 mol) of N,N-dimethylaminopyridine were added. The mixture was stirred under ice cooling. 10.0 g (0.10 mol) of methacrylic anhydride was added dropwise at a temperature not exceeding 10°C. The mixture was further aged for 15 minutes, followed by separation with dilute hydrochloric acid. The organic layer was washed three times with 200 g of water, concentrated, and the residue was crystallized with diethyl ether. The crystals were filtered and purified by silica gel column chromatography (eluent: dichloromethane-methanol mixed solvent). After recrystallization with diethyl ether, the product was filtered and dried to obtain Monomer (7) with the following structure (yield: 51%). The dimer-hexamer oligomer content was 1540 ppm. [ka]

[0262] 15 g of the monomer (7) synthesized by the above method was dissolved in 30 g of methanol, and the solution was added dropwise to 600 g of water to crystallize it. After filtration and drying, 12.3 g of the target monomer (8) was obtained. The content of dimer to hexamer oligomers was 130 ppm.

[0263] [Synthesis Example 5] Synthesis of Monomer (9) and Monomer (10) 4-chlorostyrene (manufactured by Tokyo Chemical Industry Co., Ltd.) having the following structure was used (monomer (9)). The content of dimer to hexamer oligomers was 1800 ppm. [ka]

[0264] 0.1 g of 4-tert-butylcatechol was added to 100 g of the monomer (9), and the mixture was purified by vacuum distillation at a bath temperature of 50°C and 5 Pa to obtain 95.0 g of the target monomer (10). The content of dimer to hexamer oligomers was 280 ppm.

[0265] [Polymer synthesis example 1] Synthesis of polymer 3 Under a nitrogen atmosphere, a solution was prepared by adding 49.3 g of 4-acetoxystyrene, 7.1 g of acenaphthylene, 23.6 g of Monomer (4), 8.6 g of dimethyl-2,2'-azobis-(2-methylpropionate) (Wako Pure Chemical Industries, Ltd., product name V601), and 124 g of methyl ethyl ketone as a solvent to a 300 mL dropping cylinder. Further, under a nitrogen atmosphere, 62 g of methyl ethyl ketone was added to a separate 500 mL polymerization flask, heated to 80 °C, and the solution prepared above was added dropwise over 4 hours. After the addition, stirring was continued for 18 hours while maintaining the polymerization temperature at 80 °C, and then the mixture was cooled to room temperature. The resulting polymerization solution was added dropwise to 1300 g of hexane, and the precipitated copolymer was filtered off. The filtered copolymer was washed twice with 500 g of hexane. The resulting copolymer was dissolved in a mixed solvent of 144 g of tetrahydrofuran and 48 g of methanol in a 1 L flask under a nitrogen atmosphere, and 22.3 g of ethanolamine was added and stirred at 60°C for 3 hours. The reaction solution was concentrated under reduced pressure, and the resulting concentrate was dissolved in a mixed solvent of 240 g of ethyl acetate and 60 g of water. The resulting solution was transferred to a separatory funnel, and 11.1 g of acetic acid was added and separated. The lower layer was distilled off, and 60 g of water and 14.8 g of pyridine were added to the resulting organic layer and separated. The lower layer was distilled off, and 60 g of water was added to the resulting organic layer, followed by washing and separation (a total of five times). The organic layer after separation was concentrated and then dissolved in 130 g of acetone. The resulting acetone solution was added dropwise to 1200 g of water, and the resulting crystallized precipitate was filtered and washed with water. After suction filtration for 2 hours, the filtered product was again dissolved in 130 g of acetone. The resulting acetone solution was added dropwise to 1200 g of water, and the resulting crystallized precipitate was filtered, washed with water, and dried to obtain 51.0 g of a white polymer. 13 C-NMR, 1 Measurement by H-NMR and GPC gave the following analytical results. [ka]

[0266] [Polymer synthesis example 2] Synthesis of polymer 22 Under a nitrogen atmosphere, 890 g of a 50.0 mass% propylene glycol monomethyl ether acetate (PGMEA) solution of 4-hydroxystyrene, 47.7 g of acenaphthylene, 310 g of a 54.7 mass% PGMEA solution of monomer (2), 87.0 g of triphenylsulfonium-1,1,3,3,3-pentafluoro-2-methacryloyloxypropane-1-sulfonate, 96.1 g of dimethyl-2,2'-azobis-(2-methylpropionate) (Wako Pure Chemical Industries, Ltd., V-601), and 360 g of γ-butyrolactone and 220 g of PGMEA were added to a 3,000 mL dropping cylinder to prepare a solution. Furthermore, 580 g of γ-butyrolactone was added to another 5,000 mL polymerization flask under a nitrogen atmosphere, and the solution prepared above was added dropwise over 4 hours while the flask was heated to 80 °C. After the dropwise addition was completed, stirring was continued for 18 hours while maintaining the polymerization temperature at 80°C, and then the mixture was cooled to room temperature. The resulting polymerization solution was added dropwise to 22.5 kg of diisopropyl ether, causing the copolymer to aggregate. The diisopropyl ether was removed by decantation, and the copolymer was dissolved in 2,250 g of acetone. This acetone solution was added dropwise to 22.5 kg of diisopropyl ether, and the precipitated copolymer was separated by filtration. The filtered copolymer was again dissolved in 2,250 g of acetone, and this acetone solution was added dropwise to 22.5 kg of water, and the precipitated copolymer was separated by filtration. The mixture was then dried at 40°C for 40 hours, yielding 700 g of a white polymer, Polymer 22. The resulting polymer was 13 C-NMR, 1 Measurement by H-NMR and GPC gave the following analytical results. [ka]

[0267] [Polymer Synthesis Example 3] Synthesis of Polymers 1 to 2, 4 to 21, 23 to 32, and Comparative Polymers 1 to 5 Polymers 1-2, 4-21, 23-32, and Comparative Polymers 1-5 were synthesized using the same procedures as in Polymer Synthesis Example 1 or 2, except that the type and molar ratio of each polymerizable monomer was changed. Tables 1-1 to 1-3 summarize the types and molar ratios of the monomers used in Polymers 1-32 and Comparative Polymers 1-5. Tables 2-6 show the polymerizable monomer structures of the repeating units introduced into the polymers. The Mw values ​​of the polymers were measured using GPC with tetrahydrofuran as the solvent, relative to polystyrene standards. However, for polymers containing P-1 to P-6, the Mw values ​​of Polymers 1-32 and Comparative Polymers 1-5 were measured using dimethylformamide as the solvent, relative to polystyrene standards. The Mw values ​​were 2,500 to 21,000, and the Mw / Mn values ​​were between 1.4 and 2.2.

[0268] [Table 1-1]

[0269] [Table 1-2]

[0270] [Table 1-3]

[0271] [Table 2] (The above-mentioned monomers (5) and (6) were used as polymerizable monomers to obtain A-1.)

[0272] [Table 3] (The above-mentioned monomers (9) and (10) were used as polymerizable monomers to obtain B-3.)

[0273] [Table 4] (The above-mentioned monomers (3) and (4) were used as polymerizable monomers to obtain C-1.)

[0274] [Table 5] (The above-mentioned monomers (1) and (2) were used as polymerizable monomers to obtain E-1.)

[0275] [Table 6] (The above-mentioned monomers (7) and (8) were used as polymerizable monomers to obtain P-1.)

[0276] Preparation of Resist Composition [Examples 1-1 to 1-41, Comparative Examples 1-1 to 1-5] The polymers synthesized in the Synthesis Examples (Polymers 1 to 32, Comparative Polymers 1 to 5), acid generators (PAG-A to PAG-F), and acid diffusion controllers (Q-1 to Q-4) were dissolved in organic solvents in the compositions shown in Table 7, and the resulting solutions were filtered through a 10 nm nylon filter and a 3 nm UPE filter to prepare resist compositions (R-1 to R-41, CR-1 to CR-5).

[0277] The organic solvent used in the resist compositions prepared in Examples 1-1 to 1-41 and Comparative Examples 1-1 to 1-5 in Tables 7-1 to 7-3 was a mixed solvent of 1,204 parts by mass of PGMEA, 1,204 parts by mass of ethyl lactate (EL), and 1,606 parts by mass of propylene glycol monomethyl ether (PGME). Some compositions also contained a fluorine-containing polymer (D) (polymers D1 and D2) as an additive and tetramethoxymethylglycoluril (TMGU) as a crosslinker. Some compositions also contained PF-636 (manufactured by OMNOVA SOLUTIONS) as a surfactant.

[0278] The structures of Q-1 to Q-4, PAG-A to PAG-F, and polymers D1 and D2 are as follows:

[0279] [ka]

[0280] [ka]

[0281] [ka]

[0282] [Table 7-1]

[0283] [Table 7-2]

[0284] [Table 7-3]

[0285] <Evaluation of development residue> The prepared resist compositions (R-1 to R-41, CR-1 to CR-5) were spin-coated using ACT-M (Tokyo Electron Ltd.) onto a 152 mm square mask blank with a silicon oxide outer surface that had been vapor primed with hexamethyldisilazane (HMDS). The mask was then pre-baked on a hot plate at 110°C for 600 seconds to produce a resist film with a thickness of 80 nm. The thickness of the resulting resist film was measured using an optical measuring device, Nanospec (Nanometrics). Measurements were performed at 81 locations on the blank substrate, excluding the outer edge extending 10 mm inward from the outer periphery, and the average thickness and thickness range were calculated.

[0286] The resist compositions (R-16 to R-41, CR-3 to CR-5) were baked at 120°C for 600 seconds without patterning, then developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide. The resulting development residue was evaluated using a mask defect inspection system (M9650, manufactured by Lasertec Corporation). The resist compositions (R-1 to R-15, CR-1 to CR-2) were patterned using an electron beam exposure system (EBM-5000plus, manufactured by NuFlare Technology, Inc., accelerating voltage 50 keV), subjected to PEB at 120°C for 600 seconds, and developed with a 2.38% by weight aqueous solution of TMAH. The resulting development residue was evaluated using a mask defect inspection system (M9650, manufactured by Lasertec Corporation). The total number of defects after development is shown in Table 8.

[0287] [Table 8]

[0288] As is clear from the results in Table 8, the chemically amplified resist composition of the present invention, which contains a polymer that is a polymer of a polymerizable monomer with reduced residual oligomers, can significantly reduce the number of defects caused by development residues compared to conventional resist compositions.

[0289] In addition, the above resist compositions (R-1 to R-41, CR-1 to CR-5) were spin-coated onto a 152 mm square mask blank whose outermost surface was a silicon oxide film, which had been treated with hexamethyldisilazane (HMDS) vapor prime using ACT-M (Tokyo Electron Limited) in the same manner as above, and pre-baked on a hot plate at 110°C for 600 seconds to produce a resist film with a thickness of 80 nm. The resist film was then exposed using an electron beam exposure system (EBM-5000plus, NuFlare Technology Inc., accelerating voltage 50 kV), subjected to PEB at 110°C for 600 seconds, and developed with a 2.38 mass% TMAH aqueous solution to obtain negative and positive patterns.

[0290] The obtained resist patterns were evaluated as follows: The prepared patterned mask blanks were observed with a top-down SEM (scanning electron microscope), and the exposure dose required to resolve a 200 nm 1:1 line and space (LS) at 1:1 was determined as the optimal exposure dose (μC / cm 2 ) and the minimum dimension at the exposure dose required to resolve a 200 nm LS at 1:1 was taken as the resolution (limiting resolution). All resists achieved high resolution performance of 60 nm or less at 1:1 line and space (LS).

[0291] The use of the chemically amplified resist composition of the present invention makes it possible to suppress post-development residues that can cause mask defects, and the method of forming a resist pattern using the same is useful for semiconductor device manufacturing, particularly photolithography in the processing of photomask blanks.

[0292] The present invention is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits similar effects is included within the technical scope of the present invention.

Claims

1. A polymerizable monomer that provides a repeating unit contained in a polymer compound contained in a chemically amplified negative resist composition, The polymerizable monomer provides a repeating unit A2 represented by the following general formula (A2), A polymerizable monomer, characterized in that the content of residual dimer to hexamer oligomers contained in the polymerizable monomer is 1000 ppm or less. 【Chemistry 1】 (In the formula, R Ａ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. １ is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and —CH ２ - may be replaced by -O-. １ are each independently a halogen atom, a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom. １ is a hydrogen atom, an aliphatic hydrocarbyl group having 1 to 10 carbon atoms, or an aryl group which may have a substituent, and —CH ２ - may be substituted with -O-, -C(=O)-, -O-C(=O)-, or -C(=O)-O-. Rx and Ry are each independently a hydrogen atom, a saturated hydrocarbyl group having 1 to 15 carbon atoms which may be substituted with a hydroxy group or a saturated hydrocarbyloxy group, or an aryl group which may have a substituent. However, Rx and Ry are not hydrogen atoms at the same time. Rx and Ry may be bonded to each other to form a ring together with the carbon atom to which they are bonded. y is an integer of 0 to 2. u is 0 or 1. f is an integer which satisfies 0≦f≦5+2y-g. g is an integer of 1 to 3.)

2. A polymer compound contained in a chemically amplified negative resist composition, The polymer compound is a polymerized product of the polymerizable monomer according to claim 1 .

3. A chemically amplified negative resist composition comprising: (A) The polymer compound according to claim 2 A chemically amplified negative resist composition comprising:

4. 4. The chemically amplified negative resist composition according to claim 3, wherein the component (A) is a polymeric compound containing a repeating unit A3 represented by the following general formula (A3): 【Chemistry 2】 (In the formula, R Ａ R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. １１ are each independently a halogen atom, a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom. １ is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and —CH ２ - may be replaced by -O-. s is 0 or 1. w is an integer of 0 to 2. a is an integer satisfying 0≦a≦5+2w-b. b is an integer of 1 to 3.

5. 5. The chemically amplified negative resist composition according to claim 3, wherein the component (A) is a polymeric compound containing at least one repeating unit selected from A4 to A11 represented by the following general formulas (A4) to (A11): 【Chemistry 3】 (In the formula, R Ｂ are each independently a hydrogen atom or a methyl group. １ represents a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these groups; １１ -, -C(=O)-O-Z １１ - or -C(=O)-NH-Z １１ - and Z １１ Z is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, or a phenylene group, naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. ２ is a single bond or -Z ２１ -C(=O)-O-, and Z ２１ is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. ３ represents a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -O-Z ３１ -, -C(=O)-O-Z ３１ - or -C(=O)-NH-Z ３１ - and Z ３１ Z is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, or a group having 7 to 20 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. ４ is a single bond or a hydrocarbylene group having 1 to 30 carbon atoms which may contain a heteroatom. １ and k ２ are each independently 0 or 1, ４ When is a single bond, k １ and k ２ is 0. ２１ ~R ３８ are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. ２１ and R ２２ may be bonded to each other to form a ring together with the sulfur atom to which they are attached, R ２３ and R ２４ , R ２６ and R ２７ Or R ２９ and R ３０ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. ＨＦ is a hydrogen atom or a trifluoromethyl group. － is a non-nucleophilic counterion.)

6. The chemically amplified negative resist composition according to any one of claims 3 to 5, wherein the component (A) is a polymeric compound containing at least one repeating unit selected from A12 to A14 represented by the following general formulas (A12), (A13), and (A14): 【Chemistry 4】 (In the formula, R Ａ R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. １３ and R １４ are each independently a hydroxy group, a halogen atom, an acetoxy group, a linear, branched or cyclic acyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen, a linear, branched or cyclic alkyl group having 1 to 8 carbon atoms which may be substituted with a halogen, a linear, branched or cyclic alkoxy group having 1 to 8 carbon atoms which may be substituted with a halogen, or a linear, branched or cyclic alkylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen. １５ is an acetyl group, an acetoxy group, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, a linear, branched or cyclic alkoxy group having 1 to 20 carbon atoms, a linear, branched or cyclic acyloxy group having 2 to 20 carbon atoms, a linear, branched or cyclic alkoxyalkyl group having 2 to 20 carbon atoms, an alkylthioalkyl group having 2 to 20 carbon atoms, a halogen atom, a nitro group, a cyano group, a sulfinyl group, or a sulfonyl group. A ３ is a single bond, or a linear, branched or cyclic alkylene group having 1 to 10 carbon atoms, and an ether bond may be present between the carbon-carbon bonds. o and p are each independently an integer of 0 to 4. h is an integer of 0 or 1. j is an integer of 0 to 5. k is an integer of 0 to 2.

7. The chemically amplified negative resist composition according to claim 3, wherein the component (A) is a polymeric compound that contains a repeating unit A2 represented by general formula (A2) and a repeating unit A3 represented by the following general formula (A3), but does not contain repeating units A4 to A11 represented by the following general formulas (A4) to (A11): 【Chemistry 5】 (In the formula, R Ａ R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. １１ are each independently a halogen atom, a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom. １ is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and —CH ２ - may be replaced by -O-. s is 0 or 1. w is an integer of 0 to 2. a is an integer satisfying 0≦a≦5+2w-b. b is an integer of 1 to 3. 【Chemistry 6】 (In the formula, R Ｂ are each independently a hydrogen atom or a methyl group. １ represents a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these groups; １１ -, -C(=O)-O-Z １１ - or -C(=O)-NH-Z １１ - and Z １１ Z is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, or a phenylene group, naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. ２ is a single bond or -Z ２１ -C(=O)-O-, and Z ２１ is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. ３ represents a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -O-Z ３１ -, -C(=O)-O-Z ３１ - or -C(=O)-NH-Z ３１ - and Z ３１ Z is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, or a group having 7 to 20 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. ４ is a single bond or a hydrocarbylene group having 1 to 30 carbon atoms which may contain a heteroatom. １ and k ２ are each independently 0 or 1, ４ When is a single bond, k １ and k ２ is 0. ２１ ~R ３８ are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. ２１ and R ２２ may be bonded to each other to form a ring together with the sulfur atom to which they are attached, R ２３ and R ２４ , R ２６ and R ２７ Or R ２９ and R ３０ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. ＨＦ is a hydrogen atom or a trifluoromethyl group. － is a non-nucleophilic counterion.)

8. The chemically amplified negative resist composition according to claim 3, wherein the component (A) is a polymeric compound containing either or both of a repeating unit represented by the following general formula (A2-1) and a repeating unit represented by the following general formula (A2-2), a repeating unit represented by the following general formula (A3-1), and a repeating unit represented by the following general formula (A5-1): 【Chemistry 7】 (In the formula, R Ａ is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Rx and Ry are each independently a hydrogen atom, a saturated hydrocarbyl group having 1 to 15 carbon atoms which may be substituted with a hydroxy group or a saturated hydrocarbyloxy group, or an aryl group which may have a substituent. However, Rx and Ry cannot be hydrogen atoms at the same time. Rx and Ry may be bonded to each other to form a ring together with the carbon atom to which they are bonded. g is an integer of 1 to 3. b is an integer of 1 to 3. R Ｂ are each independently a hydrogen atom or a methyl group. ２ is a single bond or -Z ２１ -C(=O)-O-, and Z ２１ R is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. ２３ ~R ２５ are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. ２３ and R ２４ may be bonded to each other to form a ring together with the sulfur atom to which they are attached.)

9. 9. The chemically amplified negative resist composition according to claim 3, wherein the polymeric compound of component (A) is a polymer of two or more polymerizable monomers, and the total amount of residual dimer-to-hexamer oligomers contained in all of the polymerizable monomers is 5,000 ppm or less.

10. 10. The chemically amplified negative resist composition according to claim 3, further comprising (B) an acid generator.

11. A photomask blank, comprising a coating of the chemically amplified negative resist composition according to any one of claims 3 to 10.

12. (1) A step of forming a resist film on a substrate using the chemically amplified negative resist composition according to any one of claims 3 to 10; (2) irradiating the resist film with a pattern using high energy radiation; and (3) A step of developing the patterned resist film using an alkaline developer.

1. A method for forming a resist pattern comprising:

13. 13. The method for forming a resist pattern according to claim 12, wherein the high energy beam is an ArF excimer laser beam, a KrF excimer laser beam, an extreme ultraviolet ray or an electron beam.

14. 14. The method for forming a resist pattern according to claim 12, wherein the outermost surface of the substrate is made of a material containing at least one of chromium, silicon, tantalum, molybdenum, cobalt, nickel, tungsten, and tin.

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