Method for producing polymer compound

Abstract

To provide a chemical amplification-type resist composition capable of suppressing development residue defect which causes mask defect while satisfying good resolution, pattern figuration, and line edge roughness, and a method of forming a resist pattern using the same.SOLUTION: A chemical amplification-type resist composition includes a polymeric compound (A) including one or two or more kinds of repeating units, where at least one or more kinds of repeating units of the repeating units contain a polymeric compound of a repeating unit obtained by polymerizing a polymerizable monomer having a residual oligomer of dimer to hexamer of 1,000 ppm or lower.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, pattern rules have become finer with the increasing integration and speed of LSI. Chemically amplified resists using acid as a catalyst are used exclusively for processing patterns of 0.2 μm or less. High-energy rays such as ultraviolet rays, far ultraviolet rays, and electron beams (EB) are used as exposure sources. In particular, 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 for light with wavelengths of around 200 nm. However, they are important materials for EB resist materials, which are a powerful technology for forming patterns smaller than the processing limit of ArF excimer lasers, and for extreme ultraviolet (EUV) resist materials because they provide high etching resistance.

[0004] Resist compositions used in such photolithography include positive types that dissolve the exposed parts to form a pattern, and negative types that leave the exposed parts to form a pattern, and the one that is easier to use is selected depending on the form of the resist pattern required. Chemically amplified negative resist compositions usually include those that contain a polymer compound that dissolves in an aqueous alkaline developer, an acid generator that is decomposed by exposure light to generate acid, and a crosslinking agent that uses an acid as a catalyst to form crosslinks between the polymer compounds to make the polymer compounds insoluble in the developer (in some cases, the polymer compound and the crosslinking agent are integrated), or those that contain those that make the polymer compounds insoluble in the developer by changing the polarity of the polymer compound, and further, usually a basic compound is added to control the diffusion of the acid generated by exposure.

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

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

[0007] On the other hand, as patterns become finer, defects caused by resist residues after development become a problem, and since they become a cause of scum residues and bridges between resist patterns, there is a risk of a significant decrease in yield in the semiconductor manufacturing process, and improvements in defect reduction are strongly desired. As an improvement method, Patent Document 7 and Patent Document 8 show the removal of unreacted monomers in the polymer, and Patent Document 9 and Patent Document 10 show a removal method by filtration. However, as a method for removing unreacted monomers in a polymer, a special crystallization process or water washing separation is used, but there are problems such as the possibility that necessary components are removed and the characteristics of the polymer are changed, the yield is reduced, and in some cases it is difficult to remove low molecular weight components from the polymer as intended.

[0008] In addition, column chromatography and filtration have productivity problems, and it is difficult to completely remove oligomers of about 2 to 8 monomers. It is actually more important to remove oligomer components that affect development residues than monomer components, and these methods are insufficient, especially for advanced lithography in semiconductor processes at the 14 nm node and beyond, and further improvements are required. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2006-201532 A [Patent Document 2] JP 2006-215180 A [Patent Document 3] JP 2008-249762 A [Patent Document 4] JP 2008-95009 A [Patent Document 5] JP 2016-65016 A [Patent Document 6] JP 2016-200805 A [Patent Document 7] JP 2003-270788 A [Patent Document 8] JP 2006-274276 A [Patent Document 9] JP 2011-70033 A [Patent Document 10] JP 2005-189789 A 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 is capable of suppressing development residue defects that cause mask defects while satisfying good resolution, pattern shape, and line edge roughness, and a method for 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 comprising: (A) A polymer compound containing one or more kinds of repeating units, at least one of which is a repeating unit formed by polymerization of a polymerizable monomer having a residual oligomer content of 1000 ppm or less of dimer to hexamer. The present invention provides a chemically amplified resist composition comprising:

[0012] In such a case, purification is not performed at the polymer stage, but rather the product is a polymer of a material in which the oligomer components are 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 polymeric 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 of dimer to hexamer. [ka] (In the formula, R A R 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, with at least one being an acid labile group.

[0014] The chemically amplified resist composition is a chemically amplified negative resist composition, 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 1000 ppm or less of dimer to hexamer. [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 -CH2- constituting the saturated hydrocarbylene group 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 the -CH2- constituting the aliphatic hydrocarbyl group may be substituted with -O-, -C(=O)-, -OC(=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.

[0015] These repeating units that undergo a reaction due to the action of the acid generated by exposure have a large impact on the occurrence of 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 these repeating units.

[0016] The component (A) may be a polymer compound containing a repeating unit A3 represented by the following general formula (A3). [ka] (In the formula, R A R 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 -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] The component (A) is preferably a repeating unit represented by the following general formulas (A4) to (A11): rank It may be a polymer compound containing at least one selected from 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 hydroxyl group. 2 is a single bond or -Z 21 -C(=O)-O-, and Z 21 Z is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. 3 is 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)-OZ31 - 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. 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, 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] The component (A) may further comprise repeating units represented by the following general formulae (A12), (A13) and (A14): rank It may be a polymer compound containing at least one selected from A12 to A14. [ka] (In the formula, R A R 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, 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. 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] As the component (A) in the present invention, such a polymer compound can be suitably used.

[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 general formula (A1) above 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 R 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 -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 hydroxyl group. 2 is a single bond or -Z 21 -C(=O)-O-, and Z 21 Z is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. 3 is 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 31Z 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. 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, 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 intended to be a chemically amplified positive resist composition, the component (A) can be such a compound.

[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 general formula (A2) above 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 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 -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 hydroxyl group. 2 is a single bond or -Z 21 -C(=O)-O-, and Z 21 Z is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. 3 is 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 31Z 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. 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, 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] In addition, the component (A) is preferably 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). [ka] (In the formula, R Ais 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.

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

[0025] It is also preferred that the polymer compound of the 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 5,000 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 a photomask blank as a substrate.

[0031] In the present invention, (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 radiation; and (3) 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] Such a pattern formation method uses the chemically amplified resist composition of the present invention, so 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, an extreme ultraviolet ray, or an electron beam.

[0034] Such a beam can be suitably used as the high energy beam.

[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 is capable of reducing development residues regardless of the type of substrate.

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

[0038] In this manner, by using a material in which the content of oligomers is suppressed at the pre-polymerization monomer stage, rather than performing purification at the polymer stage, it is possible to produce a polymer compound for use in 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.

[0039] At least one of the repeating units obtained from the polymerizable monomers having a residual oligomer content of 2-6 is preferably a repeating unit A1 represented by the following general formula (A1). [ka] (In the formula, R A R 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, with at least one being an acid labile group.

[0040] At least one of the repeating units obtained from the polymerizable monomers having a residual oligomer content of 2-6 is preferably 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 -CH2- constituting the saturated hydrocarbylene group 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 the -CH2- constituting the aliphatic hydrocarbyl group may be substituted with -O-, -C(=O)-, -OC(=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.

[0041] These repeating units which 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 which give these repeating units. Effect 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, making 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 satisfying good resolution, pattern shape, and line edge roughness.

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

[0044] As described above, there has been a demand for the development of 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.

[0045] Means for Solving the Problems The present inventors have conducted intensive research in order to achieve the above-mentioned object and 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 suppress development residue defects that cause mask defects while still achieving good resolution, pattern shape, and line edge roughness, and have thus completed the present invention.

[0046] That is, the present invention is a chemically amplified resist composition, (A) A polymer compound containing one or more kinds of repeating units, at least one of which is a repeating unit formed by polymerization of a polymerizable monomer having a residual oligomer content of 1000 ppm or less of dimer to hexamer. The chemically amplified resist composition comprises:

[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, at least one or more of the repeating units being a repeating unit formed by polymerization of a polymerizable monomer having a residual oligomer content of 1000 ppm or less of dimer to hexamer.

[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. The purification method is not particularly limited, but can be performed by washing with water, separation, distillation, recrystallization, filtration, ultrafiltration, centrifugation, high performance liquid chromatography, column chromatography, etc.

[0050] In at least one kind of repeating unit in the component (A), the residual oligomers of dimers to hexamers contained in the polymerizable monomer are 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 oligomers of dimers to hexamers, and particularly dimers to tetramers.

[0051] In addition, when heating is required for dissolution in the purification step or for extraction after purification, or when storing 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 is present in an amount exceeding 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 2-6 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, among the one or more kinds of repeating units contained in the polymer compound of component (A), which repeating unit is a repeating unit polymerized with a polymerizable monomer having a residual oligomer content of 1000 ppm or less of dimer to hexamer can be selected arbitrarily. That is, for example, it may be any of the repeating units contained in the polymer compound of component (A) described below.

[0056] As the polymerizable monomer used in the present invention, the polymerizable monomer which gives a unit having a mechanism of solubility in an alkaline developer by the action of an acid generated by exposure, in which an acid-leaving group undergoes a elimination reaction, or the polymerizable monomer which gives a unit having a mechanism of insolubility in an alkaline developer by the action of an acid-leaving group undergoes a elimination reaction, preferably contains 1000 ppm or less of residual dimer to hexamer oligomers, 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, and as for the control of oligomers, it is preferable to control dimer to tetramer oligomers. Units which undergo a reaction by the action of an acid generated by exposure have a large effect on defects in the resist composition, so it is important to suppress the oligomers.

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

[0058] [ka] (In the formula, R A R 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, with at least one being an acid labile group.

[0059] The repeating unit A1 is one in which at least one of the phenolic hydroxyl groups 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. As such an acid labile group, there is no particular limitation and any acid labile group can be used as long as it is one that has been used in many known chemically amplified resist compositions and that is eliminated by an acid to give an acidic group.

[0060] Of 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 has a phenolic hydroxyl group, preferably a hydrogen atom of a hydroxyl group of hydroxystyrene or hydroxyphenyl (meth)acrylate, substituted therein. Examples of monomers for obtaining this include the monomers described in paragraph

[0029] of JP2014-219657A. The repeating unit having an acid labile group when d represented by the repeating unit in general formula (A1) above has a hydrogen atom of a carboxyl group, particularly a hydroxyl group of (meth)acrylate, substituted therein. Examples of monomers for obtaining this include the monomers described in paragraph

[0028] of JP2014-219657A.

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

[0030] to

[0082] of JP 2014-219657 A. Preferred structures of the acid labile group include the following formulas (H-3)-1 to (H-3)-19.

[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 a phenyl group. L44 , R L46 R 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] When a tertiary alkyl group is selected as the acid labile group, it is preferable because a pattern with a small LER can be obtained even when a resist film is formed to have 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 obtained monomer for polymerization is obtained by distillation. In addition, the alkyl substituent on the tertiary carbon of the tertiary alkyl group may be a linear, branched or cyclic alkyl group 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 of 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, 1-propyl-2-methyl ... Pyrcyclopentyl group, 1-isopropylcyclopentyl group, 1-cyclopentylcyclopentyl group, 1-cyclohexylcyclopentyl group, 1-(2-tetrahydrofuryl)cyclopentyl group, 1-(7-oxanorborn-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 are included, and the structure shown below is preferable.

[0067] [ka]

[0068] [ka]

[0069] [ka]

[0070] [ka]

[0071] In addition, 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 appropriately selected depending on the design of the sensitivity of the decomposable group to acid. For example, if the design is to ensure relatively high stability and be 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 blended in the resist composition, when 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 aryl group include an isopropyl group, a sec-butyl group, a cyclopentyl group, and a cyclohexyl group.

[0075] Of the acetal groups, in order to obtain higher resolution, Y is preferably a polycyclic alkyl group having 7 to 30 carbon atoms. When Y is a polycyclic alkyl group, it is preferable that a bond is formed between the secondary carbon constituting the polycyclic ring structure and the acetal oxygen. When bonded on the secondary carbon of the ring structure, the polymer becomes a stable compound, the storage stability of the resist composition is good, and the resolution is not deteriorated, compared with when Y is bonded on the tertiary carbon. Furthermore, the glass transition temperature (Tg) of the polymer is good, and the resist pattern after development does not cause shape defects due to baking, even when compared with when Y is bonded on the primary carbon intervening a linear alkyl group having 1 or more carbon atoms.

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

[0077] [ka]

[0078] The repeating unit A1 is preferably introduced in an amount of 5 to 70 mol %, and more preferably 5 to 60 mol %, based on all repeating units in 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 preferable that the repeating unit A2 is a repeating unit formed by polymerization of 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 -CH2- constituting the saturated hydrocarbylene group 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 the -CH2- constituting the aliphatic hydrocarbyl group may be substituted with -O-, -C(=O)-, -OC(=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.

[0081] The repeating unit A2 is a repeating unit that, when irradiated with high-energy rays, causes an acid-removable group to undergo a elimination reaction due to the action of the acid generated by the acid generator, thereby inducing alkali insolubilization and a crosslinking reaction between polymers. The action of the repeating unit A2 makes it possible to more efficiently proceed with the negative reaction, thereby improving the 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 and 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; when it is 0 it is a benzene ring; when it is 1 it is a naphthalene ring; and when it is 2 it is an anthracene ring.

[0085] A 1 Examples of the alkylene group represented by the formula include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, and structural isomers of a carbon skeleton having a branched or cyclic structure. When the alkylene group contains an ether bond, when u in the general formula (A2) is 1, the ether bond may be present at any position 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 bonded to the main chain may be an ether bond, and a second ether bond may be present at any position 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 such that the lower limit is 5 mol %, 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 R 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 -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), etc.

[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 group A1, 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 kinds. The repeating unit A3 is preferably introduced in a range of 10 to 95 mol %, more preferably in a range of 30 to 85 mol %, of all repeating units of the polymer compound of component (A). However, when the repeating unit A3 contains at least one of the repeating units represented by general formula (A12) and general formula (A13) used in the present invention described later, which give the polymer high etching resistance, and the unit has a phenolic hydroxy group as a substituent, the ratio of the repeating unit A3 is also preferably 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 hydroxyl group. 2 is a single bond or -Z 21 -C(=O)-O-, and Z 21 Z is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. 3 is 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 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. 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, 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 Heteroatom represented by Child Examples of the hydrocarbylene group (divalent hydrocarbon group) having 1 to 20 carbon atoms that may be contained 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 the non-nucleophilic counter ion 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 2010-116550 A. HF Specific examples of the repeating units A6 and A10 in the case where is a trifluoromethyl group include those described in JP-A-2010-77404. Examples of the repeating units A6 and A10 in the case where is a trifluoromethyl group include those described in JP-A-2012-246265 and JP-A-2012-246426.

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

[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 thereof include those exemplified in paragraphs

[0022] and

[0023] of JP-A-2010-116550. In addition, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom may be interposed between the carbon-carbon bonds of the hydrocarbyl group, and as a result, the hydrocarbyl group may contain a hydroxyl 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, 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. 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 formulas (A5) to (A7), specific examples of the sulfonium cation structure 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 examples of the iodonium cation structure include, but are not limited to, those shown below.

[0133] [ka]

[0134] The repeating units A4 to A11 are units that generate acid by irradiation with high energy rays. It is considered that the inclusion of these units in the polymer appropriately suppresses acid diffusion, and thus a pattern with reduced LER can be obtained. In addition, the inclusion of these units in the polymer suppresses the phenomenon in which acid volatilizes from the exposed area during baking in a vacuum and reattaches to the unexposed area, which is considered to be effective in reducing LER, and in reducing defects due to suppression of undesired negative reaction in the unexposed area in the case of a negative type, and in reducing shape deterioration due to film loss in the case of a positive type. 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 the component (A) may contain at least one repeating unit selected from the 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 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. 15is 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 the alkylene group represented by the formula (A14) include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, and structural isomers of a carbon skeleton having a branched or cyclic structure. When the alkylene group contains an ether bond, when h in the general formula (A14) is 1, the ether bond may be present at any position except between the carbon at the α-position and the carbon at the β-position relative to the ester oxygen. When h is 0, the atom bonded to the main chain may be an ether oxygen, and a second ether bond may be present at any position except between the carbon at the α-position and the carbon at the β-position relative to the ether oxygen. It is preferable that the number of carbon atoms in the alkylene group is 10 or less, since sufficient solubility in an alkaline developer can be obtained.

[0138] R 15As the halogen atom, preferably, chlorine atom, bromine atom, iodine atom; as the alkyl group, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group and its structural isomer, cyclopentyl group, cyclohexyl group; as the alkoxy group, methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group and its structural isomer of the hydrocarbon part, cyclopentyloxy group, cyclohexyloxy group, etc. are mentioned. Among these, methoxy group and ethoxy group are particularly useful. In addition, acyloxy group can be easily introduced by chemical modification method even after polymerization of polymer, and can be advantageously used for fine adjustment of solubility of base polymer in alkaline developer. Examples of the acyloxy group include methylcarbonyloxy group, ethylcarbonyloxy group, propylcarbonyloxy group, butylcarbonyloxy group, pentylcarbonyloxy group, hexylcarbonyloxy group and its structural isomers, cyclopentylcarbonyloxy group, cyclohexylcarbonyloxy group, and benzoyloxy group. If the number of carbon atoms is 20 or less, the effect of controlling and adjusting the solubility in an alkaline developer as a base resin (mainly the effect of lowering) can be made appropriate, and the occurrence of scum (development defects) can be suppressed. In addition, among the above-mentioned preferable substituents, examples of the substituents that are particularly easy to prepare as a monomer and are usefully used 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 when k is 0 it represents a benzene skeleton, when it is 1 it represents a naphthalene skeleton, and when it is 2 it represents an anthracene skeleton. 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, i.e., 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 structure 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 an 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 alone or in combination of two or more. In order to obtain the effect of improving etching resistance, the content of the repeating units A12 to A14 in 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 %, or more preferably 20 mol %.

[0146] <Repeating units of (meth)acrylic acid esters having 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 finely adjust the properties of the resist film. Examples of the repeating unit of the (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. n is an integer of 0 to 3.

[0148] These units do not exhibit acidity and can be used auxiliary as units that impart adhesion to a substrate or units that adjust 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 units A1 or A2 is preferably 5 to 70 mol %, more preferably 5 to 60 mol %. Other repeating units may be contained 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 units 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 the 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 the 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 the component (A) preferably contains a repeating unit represented by the following general formula (A2-1) or (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 the 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 not containing the repeating units A4 to A11 and one containing the repeating units A4 to A11. In this case, the amount of the polymer not containing the repeating units A4 to A11 is preferably 2 to 5,000 parts by mass, more preferably 10 to 1,000 parts by mass, per 100 parts by mass of the polymer containing the repeating units A4 to A11.

[0158] In addition, when the polymer compound of component (A) used in the present invention is a polymer of two or more polymerizable monomers, the total amount of the dimer to hexamer remaining 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 dimer to tetramer oligomers. If the total amount of the dimer to hexamer remaining 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 are an important factor in reducing the yield of the semiconductor manufacturing process.

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

[0160] When a positive resist composition is used to prepare a photomask, the coating thickness in 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. is the base When the coating film on the plate is in the thin region (100 nm or less), the effect of pattern film loss due to alkaline development becomes large, and when the alkaline dissolution rate of the polymer is greater than 8 nm / min, the pattern collapses and fine patterns cannot be formed. This is particularly noticeable in photomask production, which requires a defect-free process, since the development process tends to be strong. In this invention, the dissolution rate of the base polymer in an alkaline developer is a value calculated from the amount of film loss when a polymer solution is spin-coated on a silicon wafer with a diameter of 200 mm (8 inch), baked at 100°C for 90 seconds, and then developed for 100 seconds with a 2.38% TMAH aqueous solution.

[0161] In addition, when the negative resist composition is used to prepare a photomask, the coating film thickness in 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 (aqueous solution of 2.38% by mass tetramethylammonium hydroxide (TMAH)) is generally a strong development process in order to reduce defects caused by resist residues, and is preferably 80 nm / sec or less, more preferably 50 nm / sec or less, in order to form a fine pattern. In addition, for example, when preparing an LSI chip from a wafer, when the negative resist composition of the present invention is used in an EUV exposure process, it is necessary to pattern a fine line of 50 nm or less, so the coating film thickness is often 100 nm or less, and since the pattern is likely to deteriorate due to development due to the thin film, 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 that case, 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 protected by a protecting group as necessary by a known method, and then carrying out a deprotection reaction as necessary. The copolymerization reaction is not particularly limited, but is preferably radical polymerization or anionic polymerization. For these methods, reference can be made to International Publication No. 2006 / 121096, JP-A No. 2008-102383, JP-A No. 2008-304590, and JP-A No. 2004-115630.

[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 phenomenon that the head of the pattern becomes rounded, the resolution decreases, and the LER deteriorates, as has been known in the past. On the other hand, if Mw is 50,000 or less, there is no risk of the LER increasing, particularly when forming a pattern with a pattern line width of 100 nm or less. In the present invention, Mw is a value measured in terms of polystyrene by gel permeation chromatography (GPC).

[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, in which case the molecular weight distribution is narrow. When the molecular weight distribution is narrow, no foreign matter is generated on the pattern after development, and the shape of the pattern is not deteriorated.

[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, partially fluorinated sulfonates described in JP-A-2012-189977, paragraphs

[0247] to

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

[0261] to

[0265] , JP-A-2008-111103, paragraphs

[0122] to

[0142] , and JP-A-2010-215608, paragraphs

[0080] to

[0081] . Among the specific examples, arylsulfonate-type or alkane sulfonate-type photoacid generators are preferred because they generate an acid of suitable strength for deprotecting the acid labile group of the repeating unit represented by general formula (A1). As such photoacid generators, compounds having a sulfonium anion of the structure shown below are preferred. 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, relative to 80 parts by mass of the polymer compound of the (A) component. In addition, the acid strength of the preferred anion is pKa of -1.5 or more. The pKa value is calculated using pKa DB in the software ACD / Chemsketch ver: 9.04 manufactured by 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 carboxy group, nitrogen-containing compounds having a sulfonyl group, nitrogen-containing compounds having a hydroxy group, nitrogen-containing compounds having a hydroxyphenyl group, alcoholic nitrogen-containing compounds, amides, imides, and carbamates. In particular, the primary, secondary, and tertiary amine compounds described in paragraphs

[0146] to

[0164] of JP-A-2008-111103, particularly amine compounds having a hydroxy group, an ether bond, an ester bond, a lactone ring, a cyano group, or a sulfonate ester bond, or compounds having a carbamate group described in JP-A-3790649 are preferred. Preferable 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 to correct the shape.

[0177] Further, the quencher may be an onium salt such as a sulfonium salt, an iodonium salt, or an ammonium salt of a carboxylic acid not fluorinated at the α-position, as described in JP-A-2008-158339. A sulfonic acid, an imide acid, or a methide acid fluorinated at the α-position is necessary for deprotecting an acid labile group, but a carboxylic acid not fluorinated at the α-position is released by salt exchange with an onium salt not fluorinated at the α-position. A carboxylic acid not fluorinated at the α-position hardly undergoes a deprotection reaction, and therefore functions as a quencher.

[0178] Examples of onium salts of carboxylic acids 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]. 2,6] cyclic saturated hydrocarbyl groups such as decanyl group, adamantyl group, and adamantylmethyl group; alkenyl groups such as vinyl group, allyl group, propenyl group, butenyl group, and hexenyl group; cyclic unsaturated aliphatic hydrocarbyl groups such as cyclohexenyl group; aryl groups such as phenyl group, naphthyl group, alkylphenyl group (2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-ethylphenyl group, 4-tert-butylphenyl group, 4-n-butylphenyl group, etc.), dialkylphenyl group (2,4-dimethylphenyl group, etc.), trialkylphenyl group (2,4,6-triisopropylphenyl group, etc.), alkylnaphthyl group (methylnaphthyl group, ethylnaphthyl group, etc.), dialkylnaphthyl group (dimethylnaphthyl group, diethylnaphthyl group, etc.); and aralkyl groups such as benzyl group, 1-phenylethyl group, and 2-phenylethyl group.

[0182] In addition, a portion of the hydrogen atoms of these groups may be substituted with a heteroatom-containing group such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, and a portion of the carbon atoms of these groups may be substituted with a heteroatom-containing group such as an oxygen atom, a sulfur atom or a nitrogen atom, and as a result, these groups may contain 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 of the sulfonium cations in the above general formulas (A5) to (A7) are given. 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 thereto.

[0184] [ka]

[0185] [ka]

[0186] As the quencher, a sulfonium salt of an iodized 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. 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, the saturated hydrocarbyloxy group, the saturated hydrocarbylcarbonyloxy group, and the 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. In addition, some or all of the hydrogen atoms of 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, and some of the carbon atoms of 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. In addition, 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 formula (H2) include those described in JP 2017-219836 A. These also have high absorption, a high sensitizing effect, and a high acid diffusion control effect.

[0192] In addition, the quencher may be a nitrogen atom-containing carboxylate compound described in JP 2016-200805 A. Specific examples include, but are not limited to, the following:

[0193] [ka]

[0194] [ka]

[0195] [ka]

[0196] [ka]

[0197] [ka]

[0198] Alternatively, a weak acid betaine type compound may be used as the quencher, specific examples of which include, but are not limited to, those shown below.

[0199] [ka]

[0200] Further examples of the quencher include polymer-type quenchers described in JP 2008-239918 A. These improve the rectangularity of the resist after patterning by orienting on the surface of the resist film after application of the resist composition. Polymer-type quenchers also have the effect of preventing film loss of the pattern and rounding of the pattern top when a protective film for immersion exposure 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 quencher may be used alone or in combination of two or more kinds.

[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 selected from the repeating unit represented by the following general formula (D1) (hereinafter also referred to as repeating unit D1) and the 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 purpose of increasing contrast, shielding chemical flare of acid during high-energy radiation and mixing of acid from the antistatic film during the process of applying an antistatic film material onto the resist, and suppressing unexpected and unnecessary pattern deterioration. The fluorine-containing polymer also has a surface active function, and therefore can prevent reattachment of insoluble matter that may occur during the development process to the substrate, thereby exerting an effect against development defects.

[0203] [ka]

[0204] In the formula, R B R is each independently a hydrogen atom or a methyl group. C R 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 the carbon-carbon bonds. 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 R 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 a 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 x 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 satisfying 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-. 2 is a linear, branched or cyclic hydrocarbon group or a 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 an alkyl group, an alkenyl group, and an alkynyl group, with an alkyl group being preferred. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and an n-pentyl group. In addition, a heteroatom-containing group such as an oxygen atom, a sulfur atom, or a 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 is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms and an oxygen atom intervening between the carbon-carbon bonds, or the like.

[0207] Examples of the repeating unit D1 include, but are not limited to, those shown below. In the following formula, R 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 the diffusion of acid. This improves the stability of the resist film over time, and the resolution and pattern shape do not deteriorate.

[0211] In the 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 an alkyl group, an alkenyl group, and an alkynyl group, with an alkyl group being preferred. Examples of the alkyl group include those mentioned above, as well as an n-undecyl group, an n-dodecyl group, a tridecyl group, a tetradecyl group, and a pentadecyl group. Examples of the fluorinated monovalent hydrocarbon group include groups in which some or all of the hydrogen atoms bonded to the carbon atoms of the above-mentioned monovalent hydrocarbon group 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 removed from the above-mentioned monovalent hydrocarbon group or fluorinated monovalent hydrocarbon group. 。

[0214] Specific examples of the repeating units D2 to D5 include, but are not limited to, those shown below. 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 of the fluorine-containing polymer (D). The repeating units D2 to D5 may be used alone or in combination of two or more, and is preferably 15 to 95 mol %, more preferably 20 to 85 mol %, of all repeating units of the fluorine-containing polymer (D).

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

[0046] to

[0078] of JP2014-177407A. When (D) fluorine-containing polymer contains other repeating units, the content of such units is preferably 50 mol% or less of all repeating units.

[0219] (D) The fluorine-containing polymer can be synthesized by copolymerizing each monomer protected by a protecting group as necessary by a known method, and then carrying out a deprotection reaction as necessary. The copolymerization reaction is not particularly limited, but is preferably radical polymerization or anionic polymerization. For these methods, JP-A-2004-115630 can be referred to.

[0220] The weight average molecular weight (Mw) of the fluorine-containing polymer (D) is preferably 2,000 to 50,000, more preferably 3,000 to 20,000. If Mw is 2,000 or more, the diffusion of acid can be prevented, and the resolution and stability over time can be sufficiently maintained. If Mw is 50,000 or less, the solubility in a solvent is sufficiently high, and no coating defects occur. In addition, the molecular weight distribution (Mw / Mn) of the fluorine-containing polymer (D) is preferably 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). In addition, the content is not limited to the above, and the fluorine-containing polymers described in, for example, paragraphs

[0027] to

[0041] of Japanese Patent 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 the component (E). There are no particular limitations on the organic solvent as long as it is capable of dissolving each of the components contained in the composition.

[0223] Examples of such organic solvents include ketones such as cyclohexanone and methyl-2-n-pentyl ketone, as described in paragraphs

[0144] and

[0145] of JP-A-2008-111103; 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, ethylene glycol monoethyl ether, Examples of the solvent 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, etc., can also 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, relative to 100 parts by mass of the base polymer (e.g., the (A) polymer compound). The (E) organic solvent may be used alone or in combination of two or more kinds.

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

[0227] Specific examples of crosslinking agents that can be used in the present invention include melamine compounds substituted with at least one group selected from methylol groups, alkoxymethyl groups, and acyloxymethyl groups, guanamine compounds, glycoluril compounds, urea compounds, epoxy compounds, isocyanate compounds, azide compounds, and compounds containing double bonds such as alkenyl ether groups. These may be used as additives, or may be introduced as pendant groups into polymer side chains. Compounds containing hydroxyl 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 tetramethylol guanamine, tetramethoxymethyl guanamine, and tetramethylol guanamine, or mixtures thereof; and compounds in which 1 to 4 methylol groups are acyloxymethylated, such as tetramethoxyethyl guanamine, tetraacyloxyguanamine, and tetramethylol guanamine, or mixtures thereof.

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

[0232] Examples of the urea compound include tetramethylol urea, tetramethoxymethyl urea, tetramethylol urea, and other compounds in which 1 to 4 methylol groups are methoxymethylated, 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 the above range, there is little risk of patterns being connected together and the resolution being reduced. The crosslinking agent can be used alone or in combination of two or more types.

[0237] [(G) Surfactant] A surfactant commonly used for improving the coating property on a substrate to be processed may be added to the chemically amplified resist composition of the present invention. When using a surfactant, many surfactants are known, as described in JP-A-2004-115630, and the surfactant can be selected by referring to them. The content of the surfactant is preferably 0 to 5 parts by mass per 80 parts by mass of the polymer compound of the component (A), but when the component (D) is contained in the resist, the component (D) also plays the role of a surfactant, so it is not necessary to add the surfactant to the resist.

[0238] In designing the positive resist composition, the dissolution rate of the resist coating film in an alkaline developer is 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 in the thin film region (100 nm or less), the effect of pattern film loss in alkaline development becomes large, and when the alkaline dissolution rate of the positive resist composition is greater than 10 nm / min, the pattern collapses and fine patterns cannot be formed. This is particularly noticeable in photomask production, which is required to be defect-free, because the development process tends to be strong. In the present invention, the dissolution rate in an alkaline developer is a value calculated from the amount of film loss when the positive resist composition of the present invention is spin-coated on a 6-inch silicon wafer, baked at 110° C. for 240 seconds, and then developed for 80 seconds with a 2.38% TMAH aqueous solution.

[0239] In addition, in terms of designing a negative resist composition, in consideration of 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 more, preferably 1 nm / sec or more. If the alkaline dissolution rate of the negative resist composition is 0.5 nm / sec or more, there is even less risk of development residues being generated after alkaline development, which leads to defects. In the present invention, the dissolution rate in an alkaline developer is a value calculated from the amount of film loss when the negative resist composition of the present invention is spin-coated on a 6-inch silicon wafer, baked at 110°C for 240 seconds, and then developed for 60 seconds with 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 types of repeating units and is used in a chemically amplified resist composition, comprising polymerizing at least one polymerizable monomer having a residual oligomer content of 1000 ppm or less of dimer to hexamer to obtain the polymeric compound.

[0241] In this case, it is preferable that at least one of the repeating units obtained from the polymerizable monomer having a residual oligomer content of 1000 ppm or less of dimer to hexamer 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, by using a material in which the content of oligomers is suppressed at the pre-polymerization monomer stage, rather than performing purification at the polymer stage, it is possible to produce a polymer compound for use in 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.

[0243] [Method of 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-mentioned 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 an integrated circuit (Si, SiO, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflective film, etc.), or a substrate for manufacturing a mask circuit (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 onto the substrate by a method such as spin coating so that the film thickness is, for example, 0.03 to 2 μm, and the composition is prebaked 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 a high-energy ray to irradiate a pattern. Examples of the high-energy ray include ultraviolet ray, far ultraviolet ray, excimer laser light (KrF, ArF, etc.), EUV (extreme ultraviolet ray), X-ray, gamma ray, synchrotron radiation, EB, etc. In the present invention, it is preferable to use EUV or EB (electron beam) for exposure.

[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 may 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 may be used.

[0248] Next, post-exposure baking (PEB) is performed 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 of an alkaline aqueous solution of 0.1 to 5 mass %, preferably 2 to 3 mass %, TMAH or the like, for preferably 0.1 to 3 minutes, more preferably 0.5 to 2 minutes, by a conventional method such as a dip method, a puddle method or a spray method, 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 become mask defects. The chemically amplified resist composition of the present invention can effectively reduce development defects even if there is a difference in adhesion depending on the type of substrate. Examples of such substrates include substrates having a sputtering film formed on the outermost surface of metallic 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 transmission type or a reflection type.

[0252] According to the method for forming a resist pattern of the present invention, even when a substrate (e.g., a photomask blank) 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, is used, 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. EXAMPLES

[0254] The present invention will be specifically described below with reference to synthesis examples, 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 a polystyrene-equivalent weight average molecular weight measured by gel permeation chromatography (GPC). The oligomer values ​​are calculated concentrations obtained by measuring each monomer using LC-MS (apparatus name: Thermo Fisher SCIENTIFIC / Vanquish (LC system), Q-Exactive (MS)).

[0255] [1] Synthesis of monomer [Synthesis Example 1] Synthesis of Monomer (1) and Monomer (2) In a 3L four-neck flask under nitrogen atmosphere, 42.1g of magnesium and 50mL of THF were placed, and a solution of 200g of 4-chlorostyrene dissolved in 200mL of THF was dropped at room temperature over 1 hour, and the mixture was heated to 80°C and stirred for 3 hours to prepare a Grignard reagent. The obtained Grignard reagent was cooled in an ice bath, and a solution of 100.6g of acetone dissolved in 200mL of THF was dropped therein over 1 hour. After stirring overnight, a 15% by mass aqueous solution of ammonium chloride (1,000g) was dropped to stop the reaction. A normal aqueous work-up was performed. Then, 0.02g of 4-tertiary butyl catechol was added to the crude product, and the mixture was purified by vacuum distillation at a bath temperature of 90°C and 20 Pa, and 145.2g of the target monomer (1) having the following structure was obtained (yield 62%). The dimer to hexamer oligomer was 1700ppm. [ka]

[0256] After the aqueous post-treatment, 0.2 g of 4-tert-butylcatechol was added, and the mixture was purified by vacuum distillation at a bath temperature of 70°C and 5 Pa. The same procedure as in 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) In a 3L four-neck flask under nitrogen atmosphere, 27.8g of magnesium and 50mL of THF were placed, and a solution of 200g of 1-chloro-4-[(1-methylcyclopentyl)oxy]benzene dissolved in 200mL of THF was added dropwise at room temperature over 1 hour, and the mixture was heated to 80°C and stirred for 3 hours to prepare a Grignard reagent. The obtained Grignard reagent was cooled in an ice bath, and 2.5g of dichloro(1,3-bis(diphenylphosphino)propane)nickel was added thereto and aged for 30 minutes, after which a solution of 151.2g of vinyl bromide dissolved in 200mL of THF was added dropwise over 1 hour. After stirring overnight, a 15% by mass aqueous solution of ammonium chloride (1,000g) was added dropwise to stop the reaction. A normal 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 amount of dimer to hexamer oligomers was 1600 ppm. [ka]

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

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

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

[0261] [Synthesis Example 4] Synthesis of Monomer (7) and Monomer (8) 49.0g (0.1 mol) of triphenylsulfonium 1,1,3,3,3-pentafluoro-2-hydroxypropane-1-sulfonate was dissolved in 200g of dichloromethane, and 10.1g (0.10 mol) of triethylamine and 2.4g (0.2 mol) of N,N-dimethylaminopyridine were added and stirred under ice cooling. 10.0g (0.10 mol) of methacrylic anhydride was added dropwise at a temperature not exceeding 10°C. The mixture was further aged for 15 minutes, diluted hydrochloric acid was added to separate the liquid, and the organic layer was washed three times with 200g of water, then concentrated, and diethyl ether was added to the residue to crystallize. The crystals were filtered and purified by silica gel column chromatography (eluent: dichloromethane-methanol mixed solvent), and then recrystallized again with diethyl ether, filtered, and dried to obtain monomer (7) having the following structure (yield 51%). The dimer to hexamer oligomer was 1540ppm. [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 cause crystallization. The crystallized product was filtered and dried to obtain 12.3 g of the target monomer (8). 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) (manufactured by 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, 62 g of methyl ethyl ketone was added to another 500 mL polymerization flask under a nitrogen atmosphere, and the solution prepared above was dropped over 4 hours while heating to 80 ° C. After the dropwise addition, stirring was continued for 18 hours while maintaining the polymerization temperature at 80 ° C., and then cooled to room temperature. The obtained polymerization liquid was dropped into 1300 g of hexane, and the precipitated copolymer was filtered off. The filtered copolymer was washed twice with 500 g of hexane. The copolymer obtained was dissolved in a mixed solvent of 144g of tetrahydrofuran and 48g of methanol in a 1L flask under a nitrogen atmosphere, and 22.3g 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 240g of ethyl acetate and 60g of water, and the resulting solution was transferred to a separatory funnel, and 11.1g of acetic acid was added to perform a separation operation. The lower layer was distilled off, and 60g of water and 14.8g of pyridine were added to the obtained organic layer, and a separation operation was performed. The lower layer was distilled off, and 60g of water was added to the obtained organic layer, and water washing and separation were performed (water washing and separation were performed a total of 5 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 dissolved in 130 g of acetone again, and 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 In 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) (V-601 manufactured by Wako Pure Chemical Industries, Ltd.), and 360 g of γ-butyrolactone and 220 g of PGMEA were added to a 3,000 mL dropping cylinder to prepare a solution. In addition, 580 g of γ-butyrolactone was added to another 5,000 mL polymerization flask under a nitrogen atmosphere, and the prepared solution was dropped over 4 hours while being heated to 80 ° C. After the dropwise addition, the mixture was stirred for 18 hours while maintaining the polymerization temperature at 80°C, and then cooled to room temperature. The obtained polymerization liquid was dropped into 22.5 kg of diisopropyl ether, whereby the copolymer flocculated. The diisopropyl ether was removed by decantation, and the copolymer was dissolved in 2,250 g of acetone. This acetone solution was dropped into 22.5 kg of diisopropyl ether, and the precipitated copolymer was separated by filtration. The filtered copolymer was dissolved again in 2,250 g of acetone, and this acetone solution was dropped into 22.5 kg of water, and the precipitated copolymer was separated by filtration. The mixture was then dried at 40°C for 40 hours, to obtain 700 g of a white polymer, Polymer 22. The obtained 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 1-2, 4-21, 23-32, and Comparative Polymers 1-5 Except for changing the type and introduction ratio (molar ratio) of each polymerizable monomer, polymers 1 to 2, 4 to 21, 23 to 32, and comparative polymers 1 to 5 were synthesized by the same procedure as polymer synthesis example 1 or 2. Tables 1-1 to 1-3 show the types and introduction ratios of the monomers of polymers 1 to 32 and comparative polymers 1 to 5. Tables 2 to 6 show the polymerizable monomer structures of the repeating units introduced into the polymers. The Mw of the polymers is a polystyrene-equivalent measured value by GPC using tetrahydrofuran as a solvent. However, for the polymers containing P-1 to P-6, the Mw of polymers 1 to 32 and comparative polymers 1 to 5 is a polystyrene-equivalent measured value by GPC using dimethylformamide as a solvent, and was 2500 to 21000, and Mw / Mn was 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 the polymerizable monomers for obtaining A-1.)

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

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

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

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

[0276] Preparation of the resist composition [Examples 1-1 to 1-41, Comparative Examples 1-1 to 1-5] 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 an organic solvent in the composition 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] As the organic solvent for 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, 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) was used. In addition, fluorine-containing polymer (D) (polymers D1 to D2) was added as an additive, and tetramethoxymethylglycoluril (TMGU) was added as a crosslinking agent to some of the compositions. In addition, PF-636 (manufactured by OMNOVA SOLUTIONS) was added as a surfactant to some of the compositions.

[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 film as the outermost surface that had been treated with hexamethyldisilazane (HMDS) vapor prime, 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 thickness of the resulting resist film was measured using an optical measuring device Nanospec (Nanometrics). The measurement was performed on the blank substrate The measurement was performed at 81 locations on the surface of the blank substrate, excluding the outer edge portion extending 10 mm inward from the outer periphery, and the average film thickness and film 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 drawing, and developed with a 2.38 mass% aqueous solution of tetramethylammonium hydroxide, and then the development residue was evaluated using a mask defect inspection device (M9650 manufactured by Lasertec Corporation). In addition, the resist compositions (R-1 to R-15, CR-1 to CR-2) were fully drawn using an electron beam exposure device (EBM-5000plus manufactured by NuFlare Technology, Inc., acceleration voltage 50 keV), PEB was performed at 120°C for 600 seconds, and development was performed with a 2.38 mass% aqueous solution of TMAH, and the development residue was evaluated using a mask defect inspection device (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 having a silicon oxide film as the outermost surface, which had been treated with hexamethyldisilazane (HMDS) vapor prime using ACT-M (Tokyo Electron Ltd.) 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 exposed using an electron beam exposure device (EBM-5000plus, NuFlare Technology Inc., acceleration 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 an overhead SEM (scanning electron microscope), and the exposure dose required to resolve 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 defined as the resolution (limiting resolution).All resists achieved high resolution performance of 60 nm or less in a 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. In addition, a method for forming a resist pattern using the composition 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 embodiment. The above-described embodiment is merely an example, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits similar effects is included in the technical scope of the present invention.

Claims

[Claim 1] A method for producing a polymeric compound containing one or more repeating units for use in a chemically amplified negative resist composition, comprising the steps of: A method for producing a polymer compound by polymerizing at least one polymerizable monomer having a residual oligomer content of 1000 ppm or less of dimer to hexamer to obtain the polymer compound, comprising the steps of: a repeating unit A2 represented by the following general formula (A2): 【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.)

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