JPWO2011158687A1 - Pattern forming method and radiation-sensitive resin composition - Google Patents

Abstract

The present invention provides a method for stably forming a high-precision fine pattern used in a semiconductor manufacturing process such as an IC, a circuit board such as a liquid crystal or a thermal head, and other photofabrication processes. It is an object to provide a radiation-sensitive resin composition to be used. The invention made in order to solve the above problems includes (1) a step of applying a radiation-sensitive resin composition on a substrate to form a resist film, (2) a step of exposing the resist film, and (3) A method of forming a pattern including a hole or a trench having a step of developing the exposed resist film with a developer, wherein the radiation-sensitive resin composition has a content of a structural unit having a [A] carboxy group The pattern forming method is characterized in that it contains a polymer that is 10 mol% or less and whose polarity increases by the action of an acid, and the developer contains an organic solvent.

Description

  The present invention relates to a pattern forming method used in a semiconductor manufacturing process such as an IC, a circuit board such as a liquid crystal or a thermal head, and a lithography process for other photo applications, and a radiation sensitivity used in the pattern forming method. The present invention relates to a resin composition. In particular, the present invention relates to a pattern forming method suitable for exposure with an ArF exposure apparatus and an immersion projection exposure apparatus using far ultraviolet light having a wavelength of 300 nm or less as a light source, and a radiation-sensitive resin composition used in the pattern forming method. .

  Since the development of resists for KrF excimer laser (248 nm), an image forming method called chemical amplification has been used as an image forming method for resists in order to compensate for sensitivity reduction due to light absorption. For example, in a positive chemical amplification image forming method, an acid is generated from an acid generator in an exposed area by exposure, and an alkali-insoluble group is converted into an alkali by using the above acid as a reaction catalyst by baking after exposure (PEB: Post Exposure Bake). This is an image forming method in which an exposed portion is removed by alkali development after changing to a soluble group.

With the miniaturization of semiconductor elements, the exposure light source has become shorter in wavelength and the projection lens has a higher numerical aperture (high NA). Currently, an exposure machine using an ArF excimer laser having a 193 nm wavelength as a light source is used. These resolutions and the obtained depth of focus can be expressed by the following equations as is generally well known.
(Resolution) = k1 · (λ / NA)
(Depth of focus) = ± k2 · λ / NA
Where λ is the wavelength of the exposure light source, NA is the numerical aperture of the projection lens, and k1 and k2 are coefficients related to the process.

As a technique for increasing the resolving power, a so-called immersion method has been proposed in which a high refractive index liquid (hereinafter also referred to as “immersion liquid”) is filled between the projection lens and the sample. According to this immersion method, when λ0 is the wavelength of the exposure light in the air, n is the refractive index of the immersion liquid with respect to the air, θ is the convergence angle of the light beam, and NA0 = sin θ, the above-described resolving power and depth of focus are It can be expressed by a formula.
(Resolving power) = k1 · (λ0 / n) / NA0
(Depth of focus) = ± k2 · (λ0 / n) / NA0
That is, the effect of the immersion method is equivalent to using an exposure wavelength having a wavelength of 1 / n. In other words, in the case of a projection optical system having the same NA, the depth of focus can be increased by n times by the immersion method. Further, this is effective for all pattern shapes, and can be combined with super-resolution techniques such as a phase shift method and a modified illumination method which are currently being studied.

  Furthermore, double exposure technology (Double Exposure Technology) and double patterning technology (Double Patterning Technology) have been proposed as techniques for increasing the resolution. According to these techniques, k1 in the above resolving power equation can be reduced, and the resolving power can be increased.

  Conventionally, pattern formation of an electronic device such as a semiconductor element is performed by reducing and transferring a mask or reticle pattern, which is 4-5 times the size of the pattern to be formed, to an object to be exposed such as a wafer using a reduction projection exposure apparatus. Has been done. However, with the miniaturization of dimensions, in the conventional exposure method, there is a case where light irradiated to adjacent patterns interferes with each other and the optical contrast is reduced. In view of this, a technique has been devised in which the design of an exposure mask is divided into two or more, each mask is exposed independently, and an image is synthesized. However, in these double exposure systems, it is necessary to devise division of the mask design so that the pattern on the reticle is faithfully reproduced on the object to be exposed. An example in which the effect of these double exposure methods is studied for transferring a fine image pattern of a semiconductor element is introduced in Patent Document 1 (Japanese Patent Laid-Open No. 2006-156422) and the like. In addition, the recent progress in double exposure technology is described in Non-Patent Document 1 (SPIE Proc 5754, 1508 (2005)), Non-Patent Document 2 (SPIE Proc 5377, 1315 (2004)), Non-Patent Document 3 (SPIE Proc 61571K- 1 (2006)).

  On the other hand, there are a positive type and a negative type as a method of forming a pattern. Both the positive type and the negative type are systems utilizing the fact that the solubility of the resist film in the developer changes due to a chemical reaction triggered by light irradiation. The case where the exposed portion is dissolved in the developer is called a positive type, and the case where the unexposed portion is dissolved in the developer is called a negative type.

At present, as a developer for g-line, I-line, KrF, ArF, EB, and EUV lithography, an aqueous alkaline developer of 2.38% by mass TMAH (tetramethylammonium hydroxide) is used.
As the developer other than the above, for example, an organic solvent is used (see Patent Documents 4 to 10). In particular, Patent Document 10 describes that a line-and-space pattern can be obtained by using a developer mainly composed of an organic solvent as a negative resist developer. Furthermore, a resist composition used for that purpose includes a resin containing a resin whose side chain is decomposed by the action of an acid to increase the solubility in an alkali developer and decrease the solubility in an organic solvent.

  Further, when forming a pattern including holes, it is necessary to further increase the solubility of the resin in the photoresist film in the developer as compared with the case of forming a line and space pattern.

JP 2006-156422 A JP 2001-109154 A JP 2003-76019 A JP 2001-215731 A JP 2006-227174 A JP-A-6-194847 Japanese translation of PCT publication No. 2002-525683 JP-T-2006-518779 JP 2000-199953 A JP 2008-292975 A

SPIE Proc 5754, 1508 (2005) SPIE Proc 5377, 1315 (2004) SPIE Proc 61561K-1 (2006)

  The present invention has been made based on the above situation, and a method for stably forming a high-precision fine pattern including holes in order to manufacture highly integrated and high-precision electronic devices and the like. The purpose is to provide.

The invention made to solve the above problems is
[1] (1) A step of applying a composition for forming a resist film on a substrate to form a resist film,
(2) A method of forming a pattern including a hole or a trench having a step of exposing the resist film, and (3) a step of developing the exposed resist film with a developer,
The resist film forming composition is
[A] containing a polymer whose content of structural units having a carboxy group is 10 mol% or less and whose polarity is increased by the action of an acid,
The pattern forming method is characterized in that the developer contains an organic solvent.

[2] The pattern forming method according to [1], wherein the polymer [A] has a monocyclic or polycyclic alicyclic hydrocarbon structure.

（上記式（１ａ）中、Ｒ^ｐ１１は、炭素数１〜２０の直鎖状、分岐状又は環状の１価の炭化水素基である。ｎは、１〜４の整数である。）[3] The pattern forming method according to the above [1] or [2], wherein the [A] polymer has an acid dissociable group represented by the following formula (1a).

(In said formula (1a), ^Rp11 is a C1-C20 linear, branched or cyclic monovalent hydrocarbon group. N is an integer of 1-4.)

[4] The pattern forming method according to [1], [2] or [3], in which the [A] polymer has a structural unit containing a lactone group.

（上記式中、ｎ_２は、０〜４の整数である。Ｒｂ^２は、置換基である。ｎ_２が２以上のとき、複数のＲｂ^２は、同一でも異なっていてもよく、複数のＲｂ^２が互いに結合して環を形成してもよい。）[5] The pattern formation method according to [4], wherein the lactone group is one or more groups selected from the group consisting of groups represented by the following formulas (LC1-1) to (LC1-16). is there.

(In the above formula, _{n 2,} the .rb ² is an integer of 0 to 4, when it .n ₂ is 2 or more substituents, the plurality of Rb ² may be the same or different, a plurality of Rb ² may be bonded to each other to form a ring.)

[6] The group represented by the above formula (LC1-1), (LC1-4), (LC1-5), (LC1-6), (LC1-13) or (LC1-14) The pattern forming method according to the above [4] or [5], which is one or more groups selected from the group consisting of:

[7] The above [4], [5] or [6], wherein the lactone group is a group represented by the formula (LC1-4) and n ₂ in the formula (LC1-4) is 0. ] Is a pattern forming method described in the above.

[8] The pattern forming method according to any one of [1] to [7], wherein the step (2) is performed a plurality of times.

[9] The pattern forming method according to any one of [1] to [8], further including a step (2 ′) of heating the exposed resist film after the step (2) and before the step (3). is there.

[10] The pattern forming method according to [9], wherein the step (2 ′) is performed a plurality of times.

[11] The organic solvent contained in the developer is one or more organic solvents selected from the group consisting of ketone solvents, ester solvents, alcohol solvents, amide solvents, and ether solvents [1] ] To the pattern forming method according to any one of [10].

（上記式（１）中、Ｒ及びＲ’は、それぞれ独立して、水素原子、アルキル基、シクロアルキル基、アルコキシル基、アルコキシカルボニル基、カルボキシ基、ヒドロキシル基、シアノ基又はハロゲン原子である。但し、Ｒ及びＲ’は、互いに結合して環を形成してもよい。）[12] The pattern forming method according to any one of [1] to [11], wherein the organic solvent contained in the developer is represented by the following formula (1).

(In the above formula (1), R and R ′ are each independently a hydrogen atom, alkyl group, cycloalkyl group, alkoxyl group, alkoxycarbonyl group, carboxy group, hydroxyl group, cyano group or halogen atom. However, R and R ′ may combine with each other to form a ring.)

（上記式（２）中、Ｒ’’及びＲ’’’’は、それぞれ独立して、水素原子、アルキル基、シクロアルキル基、アルコキシル基、アルコキシカルボニル基、カルボキシ基、ヒドロキシル基、シアノ基又はハロゲン原子である。但し、Ｒ’’及びＲ’’’’は、互いに結合して環を形成してもよい。Ｒ’’’は、アルキレン基又はシクロアルキレン基である。）[13] The pattern forming method according to any one of [1] to [12], wherein the organic solvent contained in the developer is represented by the following formula (2).

(In the above formula (2), R ″ and R ″ ″ each independently represent a hydrogen atom, alkyl group, cycloalkyl group, alkoxyl group, alkoxycarbonyl group, carboxy group, hydroxyl group, cyano group or A halogen atom, provided that R ″ and R ″ ″ may be bonded to each other to form a ring. R ′ ″ is an alkylene group or a cycloalkylene group.)

[14] The pattern forming method according to [12], wherein the organic solvent represented by the formula (1) is alkyl acetate.

[15] The pattern forming method according to [14], wherein the alkyl acetate is butyl acetate.

[16] The pattern forming method according to any one of [1] to [15], wherein the content of the organic solvent not containing a halogen atom in the developer is 60% by mass or more.

[17] The pattern forming method according to any one of [1] to [16], further including a step of (4) washing with a rinse liquid containing an organic solvent after the step (3).

[18] The organic solvent included in the rinse liquid is one or more organic solvents selected from the group consisting of hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents, and ether solvents. The pattern forming method according to [17] above.

[19] The pattern forming method according to [17] or [18], wherein the organic solvent contained in the rinse liquid is an alcohol solvent.

[20] The pattern forming method according to [19], wherein the alcohol solvent is a linear, branched or cyclic monovalent alcohol solvent having 6 to 8 carbon atoms.

[21] The pattern forming method according to any one of [17] to [20], wherein the water content of the rinse liquid is 30% by mass or less.

[22] A radiation-sensitive resin composition used in the pattern forming method described in [1] to [21].

  According to the present invention, it is possible to provide a method for stably forming a high-precision fine pattern including holes, and a radiation-sensitive resin composition used in this method.

  Hereinafter, modes for carrying out the present invention will be described. In addition, in the description of group (atomic group), the description which does not describe substitution and non-substitution includes what does not have a substituent and what has a substituent. For example, the alkyl group includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group). A hole refers to a pattern formed after development that is a circular hole, an elliptical hole, a short trench, or the like.

<Pattern formation method>
The pattern forming method of the present invention comprises:
(1) A step of applying a radiation-sensitive resin composition on a substrate to form a resist film,
(2) A method of forming a pattern including a hole or a trench having a step of exposing the resist film, and (3) a step of developing the exposed resist film with a developer,
The radiation sensitive resin composition is
[A] containing a polymer whose content of structural units having a carboxy group is 10 mol% or less and whose polarity is increased by the action of an acid,
The developer contains an organic solvent.

  In addition to the above steps, the pattern forming method of the present invention includes (2 ′) a step of heating the exposed resist film (hereinafter, “(2 ′)” after the step (2) and before the step (3). It is preferable to further include a “step”. In addition to the above steps, the pattern forming method of the present invention includes (4) a step of washing with a rinsing solution containing an organic solvent after the step (3) (hereinafter also referred to as “(4) step”). It is preferable that it is further included.

  According to the pattern forming method of the present invention, it is possible to stably form a high-precision fine pattern including a hole having a good shape excellent in resolution and circularity. Hereinafter, each step will be described.

  In the pattern forming method of the present invention, (1) a step of applying a radiation-sensitive resin composition on a substrate to form a resist film (hereinafter also referred to as “(1) step”), (2) the resist film Step (hereinafter also referred to as “(2) step”), (2 ′) Step of heating (PEB; Post exposure bake) the exposed resist film (hereinafter also referred to as “(2 ′) step”). ) And (3) The step of developing the exposed resist film with a negative developer (hereinafter, also referred to as “(3) step”) can be performed by a generally known method. In addition, about the radiation sensitive resin composition used in (1) process, it explains in full detail at the term of a radiation sensitive resin composition.

In the step (1) in the present invention, the substrate on which the resist film is formed is not particularly limited, and silicon, SiN, inorganic substrates such as SiO ₂ and SiN, coated inorganic substrates such as SOG, and the like, semiconductors such as IC A substrate generally used in a manufacturing process, a manufacturing process of a circuit board such as a liquid crystal or a thermal head, or a lithography process of other photo application can be used. Further, if necessary, an organic antireflection film may be formed between the resist film and the substrate.

  As the organic antireflection film, any one of a light absorber and an organic film made of a polymer material can be used. For example, DUV-30 series and DUV-40 series manufactured by Brewer Science, AR-2, AR manufactured by Shipley -3, AR-5, ARC series such as ARC29A manufactured by Nissan Chemical Co., Ltd., and other commercially available organic antireflection films can be used. In addition, an inorganic antireflection film can be used as the antireflection film, and examples thereof include antireflection films such as titanium, titanium dioxide, titanium nitride, chromium oxide, carbon, and amorphous silicon.

  In the step (2) of the present invention, the wavelength of the light source used in the exposure apparatus is not limited, but the KrF excimer laser wavelength (248 nm), ArF excimer laser wavelength (193 nm), F2 excimer laser wavelength (157 nm), EUV light (13) .5 nm) can be applied.

In the step (2) of the present invention, an immersion exposure method can be applied. Here, the immersion exposure method is a technology for filling and exposing a liquid having a high refractive index (hereinafter also referred to as “immersion liquid”) between the projection lens and the sample as a technique for increasing the resolving power. According to this immersion method, when λ0 is the wavelength of the exposure light in the air, n is the refractive index of the immersion liquid with respect to the air, θ is the convergence angle of the light beam, and NA0 = sin θ, the above-described resolving power and depth of focus are as follows: It can be expressed by a formula.
(Resolving power) = k1 · (λ0 / n) / NA0
(Depth of focus) = ± k2 · (λ0 / n) / NA0
That is, the immersion effect is equivalent to using an exposure wavelength having a wavelength of 1 / n. In other words, in the case of a projection optical system having the same NA, the depth of focus can be increased by n times by the immersion method. Further, this is effective for all pattern shapes, and can be combined with super-resolution techniques such as a phase shift method and a modified illumination method which are currently being studied. In addition, it is preferable that this process is performed several times.

  The PEB condition in the step (2 ′) can be appropriately selected depending on the composition of the photoresist composition, but is usually about 50 ° C. to 180 ° C. By this step, it is possible to smoothly remove the acid dissociable group of the polymer component [A]. In addition, this step is preferably performed a plurality of times. For example, when the exposure step is performed a plurality of times, this step may be performed for each exposure step, or after the exposure step, this step may be performed continuously a plurality of times. It is preferable to perform this process for each exposure process when it is performed once.

  When performing immersion exposure, a step of washing the surface of the resist film with an aqueous chemical solution may be performed before the resist film is heated after the step (2) and / or (2). .

  The immersion liquid is preferably a liquid that is transparent to the exposure wavelength and has a refractive index temperature coefficient as small as possible so as to minimize distortion of the optical image projected onto the resist film. Is an ArF excimer laser (wavelength: 193 nm), it is more preferable to use water from the viewpoints of availability and ease of handling in addition to the above-mentioned viewpoints.

  When water is used as the immersion liquid, an additive (liquid) that decreases the surface tension of water and increases the surface activity may be added in a small proportion. The additive is preferably one that does not dissolve the resist film on the wafer and can ignore the influence on the optical coating on the lower surface of the lens element.

  As such an additive, for example, an aliphatic alcohol having a refractive index substantially equal to that of water is preferable, and specific examples include methyl alcohol, ethyl alcohol, isopropyl alcohol and the like. By adding an alcohol having a refractive index substantially equal to that of water to water, even if the alcohol component in the water evaporates and the concentration of the content changes, there is an advantage that the refractive index change as a whole liquid can be made extremely small.

  On the other hand, distilled water is preferable as the water used as the immersion liquid because it causes distortion of the optical image projected on the resist when an opaque substance or impurities whose refractive index is significantly different from that of water are mixed with 193 nm light. Further, pure water filtered through an ion exchange filter or the like may be used.

  In the pattern forming method of the present invention, negative development using a developer containing an organic solvent is performed.

  As the organic solvent, polar solvents such as ketone solvents, ester solvents, alcohol solvents, amide solvents, ether solvents, and hydrocarbon solvents can be used.

  In the present invention, the ketone solvent is a solvent having a ketone group in the molecule. The ester solvent is a solvent having an ester group in the molecule. The alcohol solvent is a solvent having an alcoholic hydroxyl group in the molecule. An amide solvent is a solvent having an amide group in the molecule. The ether solvent is a solvent having an ether bond in the molecule. Among these, there is a solvent having a plurality of types of the above functional groups in one molecule. In that case, it corresponds to any solvent type including the functional group of the solvent. For example, diethylene glycol monomethyl ether corresponds to both alcohol solvents and ether solvents in the above classification. Further, the hydrocarbon solvent is a hydrocarbon solvent having no substituent.

  Examples of the ketone solvent include 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 4-heptanone, 1-hexanone, 2-hexanone, diisobutyl ketone, cyclohexanone, methylcyclohexanone, phenylacetone, and methyl ethyl ketone. And methyl isobutyl ketone, acetylacetone, acetonylacetone, ionone, diacetonyl alcohol, acetylcarbinol, acetophenone, methylnaphthylketone, isophorone, propylene carbonate, γ-butyrolactone, methyl amyl ketone, and the like. Of these, methyl amyl ketone is preferred.

  Examples of the ester solvents include methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, amyl acetate, isoamyl acetate, ethyl methoxyacetate, ethyl ethoxy acetate, propylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono Propyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monophenyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monopropyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monophenyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene Recall monoethyl ether acetate, 2-methoxybutyl acetate, 3-methoxybutyl acetate, 4-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-ethyl-3-methoxybutyl acetate, propylene glycol monomethyl ether acetate, Propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, 2-ethoxybutyl acetate, 4-ethoxybutyl acetate, 4-propoxybutyl acetate, 2-methoxypentyl acetate, 3-methoxypentyl acetate, 4-methoxypentyl acetate, 2-methyl-3-methoxypentyl acetate, 3-methyl-3-methoxypentyl acetate, 3-methyl-4-methoxy Nethyl acetate, 4-methyl-4-methoxypentyl acetate, propylene glycol diacetate, methyl formate, ethyl formate, butyl formate, propyl formate, ethyl lactate, butyl lactate, propyl lactate, ethyl carbonate, propyl carbonate, butyl carbonate, pyrubin Methyl acid, ethyl pyruvate, propyl pyruvate, butyl pyruvate, methyl acetoacetate, ethyl acetoacetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, methyl 2-hydroxypropionate, 2-hydroxypropionate Examples include ethyl acid, methyl-3-methoxypropionate, ethyl-3-methoxypropionate, ethyl-3-ethoxypropionate, and propyl-3-methoxypropionate.

  Examples of the alcohol solvent include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, n-hexyl alcohol, n-heptyl alcohol, alcohols such as n-octyl alcohol, n-decanol, 3-methoxy-1-butanol; glycol solvents such as ethylene glycol, diethylene glycol, triethylene glycol; ethylene glycol monomethyl ether, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, triethylene Glycol monoethyl ether, methoxymethylbutanol, ethylene glycol monoethyl ether, ethyl Glycol monopropyl ether, ethylene glycol monobutyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, may be mentioned glycol ether solvent or the like for containing a hydroxyl group such as propylene glycol monomethyl ether. Among these, it is preferable to use a glycol ether solvent.

  Examples of the ether solvent include, in addition to the glycol ether solvent containing the hydroxyl group, a glycol ether solvent not containing a hydroxyl group such as propylene glycol dimethyl ether, propylene glycol diethyl ether, diethylene glycol dimethyl ether, and diethylene glycol diethyl ether, dioxane, tetrahydrofuran, Anisole, perfluoro-2-butyltetrahydrofuran, perfluorotetrahydrofuran, 1,4-dioxane and the like can be mentioned. Of these, anisole is preferred.

  Examples of the amide solvent include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, hexamethylphosphoric triamide, 1,3-dimethyl-2-imidazolidinone and the like. Can be mentioned.

  Examples of the hydrocarbon solvent include aromatic hydrocarbon solvents such as toluene and xylene; pentane, hexane, octane, decane, 2,2,4-trimethylpentane, 2,2,3-trimethylhexane, and perfluorohexane. Aliphatic hydrocarbon solvents such as perfluoroheptane; toluene, xylene, ethylbenzene, propylbenzene, 1-methylpropylbenzene, 2-methylpropylbenzene, dimethylbenzene, diethylbenzene, ethylmethylbenzene, trimethylbenzene, ethyldimethylbenzene, Aromatic hydrocarbon solvents such as dipropylbenzene. Of these, aromatic hydrocarbon solvents are preferred.

  Among these, as a developing solution that can be used in the pattern forming method of the present invention, an ester solvent is preferable, an organic solvent represented by the above formula (1) or (2) is more preferable, and the above formula (1). Of these, alkyl acetate is particularly preferable, and butyl acetate is most preferable.

  In said formula (1), R and R 'are respectively independently a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxyl group, an alkoxycarbonyl group, a carboxy group, a hydroxyl group, a cyano group, or a halogen atom. However, R and R ′ may be bonded to each other to form a ring.

  As said R and R 'in the said Formula (1), a hydrogen atom or an alkyl group is preferable. In addition, the alkyl groups of R and R ′ may be substituted with a hydroxyl group, a carbonyl group, a cyano group, or the like.

  Examples of the organic solvent represented by the above formula (1) include methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, amyl acetate, isoamyl acetate, methyl formate, ethyl formate, butyl formate, propyl formate, ethyl lactate, and butyl lactate. , Propyl lactate, ethyl carbonate, propyl carbonate, butyl carbonate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, butyl pyruvate, methyl acetoacetate, ethyl acetoacetate, methyl propionate, ethyl propionate, propyl propionate, propion Examples include isopropyl acid, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, and the like.

  Of these, solvents in which R and R 'are unsubstituted alkyl groups are preferred, alkyl acetates are more preferred, and butyl acetate is more preferred.

  The organic solvent represented by the above formula (1) may be used in combination with one or more other organic solvents. In this case, the combined solvent is not particularly limited as long as it can be mixed with the organic solvent represented by the above formula (1) without being separated, and the organic solvents represented by the above formula (1) may be used in combination. The organic solvent represented by the above formula (1) is mixed with an organic solvent selected from the group consisting of other ester solvents, ketone solvents, alcohol solvents, amide solvents, ether solvents and hydrocarbon solvents. May be used. One or more combined solvents can be used, but one is preferable from the viewpoint of obtaining stable performance. When mixing and using 1 type of combined use solvent, the mixing ratio of the organic solvent represented by the said Formula (1) and a combined use solvent is 20: 80-99: 1 normally, Preferably it is 50: 50-97: 3, More preferably, it is 60: 40-95: 5, More preferably, it is 60: 40-90: 10.

  As described above, the organic solvent represented by the above formula (2) is also preferable as the organic solvent contained in the developer used in the pattern forming method of the present invention.

  In the above formula (2), R ″ and R ″ ″ each independently represent a hydrogen atom, alkyl group, cycloalkyl group, alkoxyl group, alkoxycarbonyl group, carboxy group, hydroxyl group, cyano group or halogen. Is an atom. However, R ″ and R ′ ″ ″ may be bonded to each other to form a ring. R ′ ″ is an alkylene group or a cycloalkylene group.

  In the above formula (2), R ″ and R ′ ″ ″ are preferably a hydrogen atom or an alkyl group. R ′ ″ is preferably a hydrogen atom or an alkyl group. The alkyl group represented by R ″ and R ′ ″ ″ may be substituted with a hydroxyl group, a carbonyl group, a cyano group or the like. R ″ ″ may have an ether bond in the alkylene chain.

  Examples of the organic solvent represented by the above formula (2) include propylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monophenyl ether acetate, diethylene glycol monomethyl. Ether acetate, diethylene glycol monopropyl ether acetate, diethylene glycol monophenyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol Nopropyl ether acetate, methyl-3-methoxypropionate, ethyl-3-methoxypropionate, ethyl-3-ethoxypropionate, propyl-3-methoxypropionate, ethyl methoxyacetate, ethyl ethoxyacetate, 2 -Methoxybutyl acetate, 3-methoxybutyl acetate, 4-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-ethyl-3-methoxybutyl acetate, 2-ethoxybutyl acetate, 4-ethoxybutyl acetate, 4 -Propoxybutyl acetate, 2-methoxypentyl acetate, 3-methoxypentyl acetate, 4-methoxypentyl acetate, 2-methyl-3-methoxypentyl acetate, 3-methyl-3-methoxypentyl acetate 3-methyl-4-methoxy pentyl acetate, 4-methyl-4-methoxy pentyl acetate, and the like.

  The organic solvent represented by the above formula (2) may be used in combination with one or more other organic solvents. The combined solvent in this case is not particularly limited as long as it can be mixed without being separated into the organic solvent represented by the above formula (2), and the organic solvents represented by the above formula (2) may be used in combination. The organic solvent represented by the above formula (2) is mixed with another organic solvent selected from ester solvents, ketone solvents, alcohol solvents, amide solvents, ether solvents and hydrocarbon solvents. May be. One or more solvents can be used in combination, but it is preferably one solvent in order to obtain stable performance. When mixing and using 1 type of combined use solvent, the mixing ratio of the organic solvent represented by the said Formula (2) and a combined use solvent is 20: 80-99: 1 normally, Preferably it is 50: 50-97: 3, More preferably, it is 60: 40-95: 5, More preferably, it is 60: 40-90: 10.

  The developer used in the pattern forming method of the present invention may be used by mixing a plurality of the above organic solvents, or may be used by mixing with other solvents or water.

  As the organic solvent contained in the developer used in the pattern forming method of the present invention, an organic solvent containing no halogen atom is preferably used from the viewpoint of cost reduction and environmental consideration. The content of the organic solvent not containing halogen atoms in the total weight of all solvents used in the negative development is usually 60% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, More preferably, it is 97 mass% or more.

  The boiling point of the organic solvent contained in the developer in the pattern forming method of the present invention is preferably 50 ° C. or higher and lower than 250 ° C. Further, the ignition point of the organic solvent is preferably 200 ° C. or higher.

  An appropriate amount of a surfactant can be added to the developer used in the pattern forming method of the present invention, if necessary.

  As the surfactant, for example, an ionic or nonionic fluorine-based and / or silicon-based surfactant can be used. Examples of these fluorine and / or silicon surfactants include, for example, JP-A No. 62-36663, JP-A No. 61-226746, JP-A No. 61-226745, JP-A No. 62-170950, JP 63-34540 A, JP 7-230165 A, JP 8-62834 A, JP 9-54432 A, JP 9-5988 A, US Pat. No. 5,405,720, etc. The surfactants described in US Pat. Nos. 5,360,692, 5,529,881, 5,296,330, 5,346,098, 5,576,143, 5,294,511, and 5,824,451 can be mentioned. . Among these, nonionic surfactants are preferable, and among them, fluorine-based surfactants and silicon-based surfactants are more preferable.

  The amount of the surfactant used is usually 0.001 to 5% by mass, preferably 0.005 to 2% by mass, and more preferably 0.01 to 0.5% by mass, based on the total amount of the developer.

  As a developing method in the pattern forming method of the present invention, for example, a method in which a substrate is immersed in a tank filled with a developer (dip method) for a certain time, a developer is raised on the surface of the substrate by surface tension, and is allowed to stand for a certain time. Developing method (paddle method), spraying developer solution onto the substrate surface (spray method), and applying developer solution while scanning the developer application nozzle at a constant speed on a substrate rotating at a constant speed A continuing method (dynamic dispensing method) or the like can be applied.

  Further, after the step of performing the development, a step of stopping the development may be performed while substituting with another solvent.

  Furthermore, it is preferable to include the process ((4) process) wash | cleaned using the rinse liquid containing an organic solvent after the process of performing the said image development.

  In the step (4), a rinsing liquid usually containing at least one organic solvent selected from the group consisting of hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents and ether solvents. Can be used.

  Examples of ketone solvents include 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 4-heptanone, 1-hexanone, 2-hexanone, diisobutylketone, cyclohexanone, methylcyclohexanone, phenylacetone, methylethylketone, Examples include methyl isobutyl ketone, acetylacetone, acetonylacetone, ionone, diacetonyl alcohol, acetylcarbinol, acetophenone, methylnaphthyl ketone, isophorone, propylene carbonate, and the like.

  Examples of the ester solvent include methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, amyl acetate, propylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl-3-ethoxypropyl Pionate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, methyl formate, ethyl formate, butyl formate, propyl formate, ethyl lactate, butyl lactate, propyl lactate and the like can be mentioned.

  Examples of alcohol solvents include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, n-hexyl alcohol, n-heptyl alcohol, n- Alcohols such as octyl alcohol and n-decanol, glycol solvents such as ethylene glycol, diethylene glycol, triethylene glycol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol, propylene glycol, diethylene glycol monomethyl ether, triethylene glycol mono List glycol ether solvents such as ethyl ether and methoxymethylbutanol. Can.

  Examples of the ether solvent include dioxane, tetrahydrofuran and the like in addition to the glycol ether solvent.

  As the amide solvent, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, hexamethylphosphoric triamide, 1,3-dimethyl-2-imidazolidinone and the like can be used. .

  Examples of the hydrocarbon solvent include aromatic hydrocarbon solvents such as toluene and xylene, and aliphatic hydrocarbon solvents such as pentane, hexane, octane and decane.

  As the rinsing liquid containing an organic solvent, it is preferable to use at least one solvent selected from the above hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents and amide solvents, alcohol solvents and It is more preferable to use at least one solvent selected from ester solvents, and alcohol solvents are more preferable. Of these, it is particularly preferable to use a monohydric alcohol having 6 to 8 carbon atoms. Examples of the monohydric alcohol having 6 to 8 carbon atoms include linear, branched, and cyclic monohydric alcohols, specifically, 4-methyl-2-pentanol, 1-hexanol, and 1-heptanol. 1-octanol, 2-hexanol, 2-heptanol, 2-octanol, 3-hexanol, 3-heptanol, 3-octanol, 4-octanol, benzyl alcohol, etc., among these, 4-methyl- 2-Pentanol, 1-hexanol, 2-heptanol and 2-hexanol are preferred, and 4-methyl-2-pentanol, 1-hexanol and 2-hexanol are more preferred.

  A plurality of the rinse solutions may be mixed, or may be used by mixing with an organic solvent other than the above. The rinsing liquid may be mixed with water, but the water content in the rinsing liquid is usually 30% by mass or less, preferably 10% by mass or less, more preferably 5% by mass or less, and further preferably 3% by mass. % Or less. By setting the water content to 30% by mass or less, good development characteristics can be obtained.

  An appropriate amount of a surfactant can be added to the rinsing liquid as necessary. As the surfactant, for example, an ionic or nonionic fluorine-based and / or silicon-based surfactant can be used. The amount of the surfactant used is usually 0.001 to 5% by mass, preferably 0.005 to 2% by mass, and more preferably 0.01 to 0.5% by mass with respect to the total amount of the developer.

  (4) Although there is no particular limitation on the cleaning method used when the resist after negative development in the step is cleaned using the rinsing liquid containing the organic solvent, the resist rotates at a constant speed, for example. A method of continuing to apply the rinse solution onto the substrate (rotary coating method), a method of immersing the substrate in a bath filled with the rinse solution for a certain period of time (dip method), and a method of spraying the rinse solution onto the substrate surface (spray method) Etc. can be applied.

  Further, after the development process or the rinsing process, a process of removing the developer or the rinsing liquid adhering to the pattern with a supercritical fluid can be performed.

  Furthermore, after the development processing, the rinsing processing or the processing with the supercritical fluid, a heat processing can be performed in order to remove the solvent remaining in the pattern. The heating temperature is not particularly limited as long as a good resist pattern can be obtained, and is usually 40 ° C to 160 ° C. The heat treatment may be performed a plurality of times.

  In the pattern forming method of the present invention, positive development can also be performed following the negative development. When performing positive development, an alkali developer is preferably used.

  Examples of the alkali developer used for positive development include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia, ethylamine, and n-propylamine. Primary amines; secondary amines such as diethylamine and di-n-butylamine; tertiary amines such as triethylamine and methyldiethylamine; alcohol amines such as dimethylethanolamine and triethanolamine; tetramethylammonium hydroxide and tetraethyl Examples include quaternary ammonium salts such as ammonium hydroxide; alkaline aqueous solutions such as cyclic amines such as pyrrole and pihelidine.

  Furthermore, an appropriate amount of alcohol, surfactant or the like can be added to the alkaline aqueous solution.

  The alkali concentration of the alkali developer is usually 0.1 to 20% by mass. The pH of the alkali developer is usually from 10.0 to 15.0. As the positive developer in the present invention, a 2.38% aqueous solution of tetramethylammonium hydroxide is particularly desirable.

  As the rinsing liquid in the rinsing treatment performed after the positive development, pure water is used, and an appropriate amount of a surfactant can be added and used.

<Radiation sensitive resin composition>
The radiation sensitive resin composition of this invention is a radiation sensitive resin composition used suitably for the pattern formation method of this invention, Comprising: The content rate of the structural unit which has [A] carboxy group is 10 mol% or less. And a polymer whose polarity is increased by the action of an acid. The radiation sensitive resin composition may contain other components in addition to the [A] polymer as long as the effects of the present invention are not impaired. Hereinafter, each component will be described in detail.

<[A] polymer>
Since the polarity of the polymer [A] is increased by the action of an acid, the composition for forming a resist film contains the polymer [A], whereby the solubility in an organic solvent-containing developer is reduced in the exposed area. , A desired pattern can be formed. Examples of such a polymer [A] include a group (hereinafter referred to as “an alkali-soluble group”) that decomposes in the main chain and / or side chain of the polymer by the action of an acid to generate a polar group (hereinafter also referred to as “alkali-soluble group”). A polymer having an "acid-dissociable group" (hereinafter also referred to as an "acid-dissociable polymer") is preferable. [A] When the polymer has the acid dissociable group, the radiation-sensitive resin composition uses a developer containing an organic solvent in which the polarity of the polymer changes greatly before and after irradiation with radiation. Thus, the dissolution contrast in the case of development is improved, and it is suitably used as a radiation-sensitive resin composition for negative development.

  In addition, since the content of the structural unit having a carboxy group in the [A] polymer is 10 mol% or less, the composition for forming a resist film has high solubility in a developer containing an organic solvent, and exposure. Excellent dissolution contrast between the part and the unexposed part.

  Furthermore, the [A] polymer preferably has a monocyclic or polycyclic alicyclic hydrocarbon structure. Since the polymer having the monocyclic or polycyclic alicyclic hydrocarbon structure generally has high hydrophobicity, the [A] polymer has the monocyclic or polycyclic alicyclic hydrocarbon structure, so that the radiation sensitivity is increased. The developable resin composition can improve developability with a developer containing an organic solvent.

  [A] The polymer preferably has a structural unit containing a lactone group. [A] When the polymer has a structural unit containing a lactone group, the adhesion of the resist film formed using the resist film-forming composition to the substrate can be improved. Here, the lactone group refers to a group obtained by removing one hydrogen atom of the lactone ring, and the lactone ring refers to a monocyclic or polycyclic ring having a structure represented by —O—C (O) —. .

  The radiation sensitive resin composition of the present invention containing the [A] polymer as described above can be suitably used in the case of irradiation with ArF excimer laser light.

  [A] an acid-dissociable group of a polymer, a monocyclic or polycyclic alicyclic hydrocarbon structure, a structural unit having a carboxy group having a content of 10 mol% or less, and a structural unit suitably containing a lactone group Is described in detail below. In addition, unless the effect of this invention is impaired, the [A] polymer may have other structures other than the above.

<Acid dissociable group>
[A] The acid dissociable group of the polymer is preferably a group in which the hydrogen atom of the alkali-soluble group is substituted with a group capable of leaving with an acid.

  Examples of the alkali-soluble groups include phenolic hydroxyl groups, carboxylic acid groups, fluorinated alcohol groups, sulfonic acid groups, sulfonamido groups, sulfonylimide groups, (alkylsulfonyl) (alkylcarbonyl) methylene groups, and (alkylsulfonyl) (alkyl Carbonyl) imide group, bis (alkylcarbonyl) methylene group, bis (alkylcarbonyl) imide group, bis (alkylsulfonyl) methylene group, bis (alkylsulfonyl) imide group, tris (alkylcarbonyl) methylene group, tris (alkylsulfonyl) Examples include a group having a methylene group.

  Of these, a carboxylic acid group, a fluorinated alcohol group (more preferably hexafluoroisopropanol), and a sulfonic acid group are preferable.

Examples of the group capable of leaving by the acid, for example, ^{-C (R 36) (R 37} ) (R 38), - C (R 36) (R 37) (OR 39), - C (R 01) (R 02 ) (OR ³⁹ ) and the like. However, R < ³⁶ > -R < ³⁹ > is respectively independently an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or an alkenyl group. R ³⁶ and R ³⁷ may be bonded to each other to form a ring. R ^{01 to} R ⁰² are each independently a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or an alkenyl group. Therefore, as a specific acid dissociable group, a cumyl ester group, an enol ester group, an acetal ester group, and a tertiary alkyl ester group are preferable, and a tertiary alkyl ester group is more preferable.

  The [A] polymer preferably has a monocyclic or polycyclic alicyclic hydrocarbon structure described later, and the acid dissociable groups are represented by the following formulas (pI) to (pV) described later. It is contained in at least one structural unit among the structural unit (I) having an alicyclic hydrocarbon structure, the structural unit (II) represented by the following formula (II-AB), and the structural unit of the copolymer component described later. obtain. Among these, the acid dissociable group is preferably contained in the structural unit (I) including an alicyclic hydrocarbon structure represented by the following formulas (pI) to (pV). Each specific example will be described in the description of each structure described later.

<Monocyclic or polycyclic alicyclic hydrocarbon structure>
[A] The polymer preferably has a monocyclic or polycyclic alicyclic hydrocarbon structure. [A] The polymer may have the above monocyclic or polycyclic alicyclic hydrocarbon structure at any site such as a main chain or a side chain in the polymer. [A] When the polymer has a monocyclic or polycyclic alicyclic hydrocarbon structure, the radiation-sensitive resin composition can improve solubility in a developer containing an organic solvent.

  [A] The polymer is a polymer whose polarity is increased by the action of an acid, but is preferably an alicyclic hydrocarbon-based acid dissociable polymer further having a monocyclic or polycyclic alicyclic hydrocarbon structure. . Such [A] polymer is the structural unit (I) and / or having at least one structure selected from the group consisting of alicyclic hydrocarbon structures represented by the following formulas (pI) to (pV). It is more preferable to have a structural unit (II) represented by the following formula (II-AB).

[Structural unit (I)]
The structural unit (I) is a structural unit having at least one structure selected from the group consisting of alicyclic hydrocarbon structures represented by the following formulas (pI) to (pV).

In the above formulas (pI) to (pV), R ¹¹ is a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group or a sec-butyl group. Z is an atomic group necessary for forming a cycloalkyl group together with the carbon atom to which R ¹¹ is bonded. R ^{12 to} R ¹⁶ are each independently a linear or branched alkyl group having 1 to 4 carbon atoms or a cycloalkyl group. However, at least one of R ^{12 to} R ¹⁴ , or any of R ¹⁵ and R ¹⁶ is a cycloalkyl group. R ^{17 to} R ²¹ are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, or a cycloalkyl group. However, at least one of R ^{17 to} R ²¹ is a cycloalkyl group. In addition, any one of R ¹⁹ and R ²¹ is a linear or branched alkyl group having 1 to 4 carbon atoms, or a cycloalkyl group. R ^{22 to} R ²⁵ are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, or a cycloalkyl group. However, at least one of R ^{22 to} R ²⁵ is a cycloalkyl group. R ²³ and R ²⁴ may be bonded to each other to form a ring.

The cycloalkyl group represented by R ^{11 to} R ²⁵ in the above formulas (pI) to (pV) or the cycloalkyl group formed together with the carbon atom to which Z and R ¹¹ are bonded may be monocyclic or polycyclic. . Specifically, a group having a monocyclo, bicyclo, tricyclo, tetracyclo structure or the like having 5 or more carbon atoms is preferable. The carbon number is preferably 6-30, more preferably 7-25. Moreover, these cycloalkyl groups may have a substituent.

  Among these, adamantyl group, noradamantyl group, decalin residue, tricyclodecanyl group, tetracyclododecanyl group, norbornyl group, cedrol group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclodecanyl group, A cyclododecanyl group is more preferable, and an adamantyl group, a norbornyl group, a cyclohexyl group, a cyclopentyl group, a tetracyclododecanyl group, and a tricyclodecanyl group are particularly preferable.

  As said substituent, a C1-C4 alkyl group, a halogen atom, a hydroxyl group, a C1-C4 alkoxy group, a carboxy group, a C2-C6 alkoxycarbonyl group, etc. are mentioned. The alkyl group, alkoxy group, alkoxycarbonyl group and the like may further have a substituent, and examples of the substituent include a hydroxyl group, a halogen atom and an alkoxy group.

  The structural unit (I) preferably includes a structure in which an alkali-soluble group is protected by a structure represented by the above formulas (pI) to (pV). In the radiation-sensitive resin composition containing the [A] polymer having such a structural unit (I), the structure represented by the above formulas (pI) to (pV) is dissociated by the action of an acid. Alkali-soluble groups appear, the polarity increases, and it becomes hardly soluble or insoluble in a developer containing an organic solvent. Examples of the alkali-soluble group include various groups known in this technical field. For example, the groups exemplified as the alkali-soluble group in the description of the acid-dissociable group can be given.

  Examples of the structure in which the alkali-soluble group is protected by the structure represented by the above formulas (pI) to (pV) include, for example, a hydrogen atom of a carboxylic acid group, a sulfonic acid group, a phenol group, and a thiol group. The structure substituted by the structure represented by (pV), etc. are mentioned, The structure by which the hydrogen atom of the carboxylic acid group and the sulfonic acid group was substituted by the structure represented by the said formula (pI)-(pV) is preferable. .

  As the structural unit (I), a structural unit represented by the following formula (pA) is more preferable.

In said formula (pA), R is a hydrogen atom, a halogen atom, or a C1-C4 linear or branched alkyl group. A plurality of R may be the same or different. A is a single bond, an alkylene group, an ether group, a thioether group, a carbonyl group, an ester group, an amide group, a sulfonamide group, a urethane group, a urea group, or a group formed by combining these groups. R ^p1 is any group of the above formulas (pI) to (pV).

  As A in the formula (pA), a single bond is preferable.

  Examples of the structural unit (I) represented by the above formula (pA) include a structural unit represented by the following formula.

In the above formula, R ^x is a hydrogen atom, CH ₃ or CH ₂ OH. R ^xa and R ^xb are alkyl groups having 1 to 4 carbon atoms.

R ^p1 in the above formula (pA) is preferably a group represented by the above formula (1a). [A] When a polymer has group represented by the said Formula (1a), when forming the pattern containing a hole, high resolution can be expressed.

In the above formula (1a), R ^p11 is a hydrogen atom, a linear, branched or cyclic monovalent hydrocarbon group having 1 to 20 carbon atoms. n is an integer of 1 to 4.

  Of the structural unit (I) represented by the above formula (pA), a structural unit having a group represented by the above formula (1a) is preferable, and examples thereof include a structural unit represented by the following formula.

  In said formula, R is synonymous with the said formula (pA).

  [A] The content of the structural unit (I) in the polymer is 10 mol% to 95 mol%, preferably 20 mol% to 90 mol%, more preferably 40 mol% to 90 mol%, 40 mol% or more is more preferable.

  As a monomer which gives structural unit (I), the compound etc. which are represented by a following formula are mentioned, for example.

[Structural unit (II)]
The structural unit (II) is represented by the following formula (II-AB). [A] When the polymer has the structural unit (II) having the acid dissociable alicyclic hydrocarbon structure having the above specific structure, the radiation-sensitive resin composition has excellent resolution and is organic. The developability with a developer containing a solvent can be improved.

In the above formula (II-AB), R ^{11 ′} and R ^{12 ′} each independently represent a hydrogen atom, a cyano group, a halogen atom or an alkyl group. Z ′ is an atomic group for forming an alicyclic structure together with the carbon atom to which R ^{11 ′} is bonded and the carbon atom to which R ^{12 ′} is bonded.

In the above formula (II-AB), examples of the halogen atom represented by R ^{11 ′} and R ^{12 ′} include a chlorine atom, a bromine atom, a fluorine atom, and an iodine atom.

In said formula (II-AB), as an alkyl group represented by R < ^{11 '>} , R <^12'>, a C1-C10 linear or branched alkyl group etc. are mentioned, for example.

  In the above formula (II-AB), the atomic group for forming the alicyclic structure of Z ′ is an atomic group that forms an alicyclic hydrocarbon which may have a substituent. An atomic group for forming an alicyclic hydrocarbon of the formula is preferred.

  Examples of the alicyclic structure formed include those similar to the alicyclic hydrocarbon structures of the general formulas (pI) to (pV). The alicyclic structure may have a substituent.

  As the structural unit (II), a structural unit represented by the following formula (II-AB1) or (II-AB2) is preferable.

In the formulas (II-AB1) and (II-AB2), R ^{13 ′ to} R ^{16 ′} are each independently decomposed by the action of a hydrogen atom, a halogen atom, a cyano group, —COOH, —COOR ⁵ , or an acid. Group, —C (═O) —XA′—R ^{17 ′} , an alkyl group, or a cycloalkyl group. However, any two or more groups of R ^{13 ′ to} R ^{16 ′} may combine to form a ring. R ⁵ is a group having an alkyl group, a cycloalkyl group or a lactone structure. X represents an oxygen atom, a sulfur atom, -NH -, - NHSO ₂ - or -NHSO ₂ NH-. A ′ is a single bond or a divalent linking group. R ^{17 ′} is a group having —COOH, —COOR ⁵ , —CN, a hydroxyl group, an alkoxy group, —CO—NH—R ⁶ , —CO—NH—SO 2 —R ⁶ or a lactone structure. R ⁶ is an alkyl group or a cycloalkyl group. n is 0 or 1.

In the formula (II-AB1) and the formula (II-AB2), R ^{13 ′ to} R ^{16 ′} are an atomic group or a bridged type fat for forming an alicyclic structure in the formula (II-AB). It can also be a substituent of the atomic group Z ′ for forming a cyclic structure.

  Examples of the structural unit represented by the above formula (II-AB1) or (II-AB2) include a structural unit represented by the following formula.

  In the [A] polymer, the acid dissociable group is a structural unit (I) having an alicyclic hydrocarbon structure represented by the above formulas (pI) to (pV), or the above formula (II-AB). It may be contained in the structural unit (II) represented or the structural unit of the copolymerization component described later. Among these, the acid dissociable group is preferably contained in the structural unit (I) having a partial structure including the alicyclic hydrocarbon represented by the above formulas (pI) to (pV).

<Structural unit having carboxy group>
[A] In the polymer, the content of the structural unit having a carboxy group (hereinafter also referred to as “structural unit (III)”) is 10 mol% or less. It is preferable that the content rate of the structural unit (III) in the [A] polymer which the said radiation sensitive resin composition contains is 0-5 mol% with respect to all the structural units, and has structural unit (III). More preferably not. When the content of the structural unit (III) is in the above range, when forming a pattern having a hole portion such as a contact hole, the solubility in a negative developer containing an organic solvent as a main component is improved. Can do.

  Further, when the [A] polymer includes a structural unit having a lactone group, which will be described later, the total content of the structural unit having a lactone group and the structural unit (III) is the total structural unit constituting the [A] polymer. 100 mol% is usually 20 mol% to 65 mol%, preferably 30 to 60 mol%, and the molar ratio of the structural unit having a lactone group to the structural unit (III) is usually 50/50, preferably 75 / 25, particularly preferably 100/0. When the total content of the structural unit having a lactone group and the structural unit (III) and the molar ratio of the structural unit having the lactone group to the structural unit (III) are within the above ranges, the exposed area is insoluble and unexposed to the negative developer. The solubility balance of the exposed area becomes good and a good pattern shape can be obtained.

  The structural unit (III) includes a structural unit in which a carboxy group is directly bonded to the main chain of the polymer, such as a structural unit of acrylic acid or methacrylic acid, or a carboxy group in the main chain of the polymer via a linking group. The structural unit etc. which are couple | bonded are mentioned.

  As a monomer which gives structural unit (III), the compound etc. which are represented by a following formula are mentioned, for example.

<Structural unit containing lactone group>
The [A] polymer of the present invention preferably has a structural unit containing a lactone group. [A] When the polymer contains a structural unit having a lactone group, the radiation-sensitive resin composition can improve adhesion to a substrate or the like. The lactone group may be any group as long as it contains a lactone structure, but is preferably a group containing a 5- to 7-membered ring lactone structure, and forms a bicyclo structure or a spiro structure in the 5- to 7-membered ring lactone structure. In this way, a group in which another ring structure is condensed is more preferable.

  Specifically, the lactone group is preferably a lactone group represented by any one of the above formulas (LC1-1) to (LC1-16). Of these, groups represented by the above formulas (LC1-1), (LC1-4), (LC1-5), (LC1-6), (LC1-13), and (LC1-14) are more preferable. By using the specific lactone group, line edge roughness and development defects are improved.

In the above formulas (LC1-1) to (LC1-16), Rb ² is a monovalent organic group. n ² is an integer of 0-4. However, when n ² is 2 or more, the plurality of Rb ² may be the same or different, and the plurality of Rb ² may be bonded to each other to form a ring.

In the above formulas (LC1-1) to (LC1-16), the monovalent organic group represented by Rb ² is an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 4 to 7 carbon atoms, or the number of carbon atoms. Examples thereof include an alkoxy group having 1 to 8 carbon atoms, an alkoxycarbonyl group having 1 to 8 carbon atoms, a carboxy group, a halogen atom, a hydroxyl group, a cyano group, and an acid dissociable group.

Examples of the structural unit containing the lactone group include structural units having a lactone group represented by any one of the above formulas (LC1-1) to (LC1-16), such as the above formula (II-AB1) or (II-AB2) wherein at least one of ^{R 13 '~R 16'} in Although ^{R 5} in the structural unit (e.g., -COOR ⁵ having a group represented by the formula (LC1-1) ~ (LC1-16) And a structural unit represented by the following formula (AI), and the like.

In the above formula (AI), Rb ⁰ represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 4 carbon atoms. Ab is a divalent group formed by a single bond, an alkylene group, a divalent linking group having a monocyclic or polycyclic alicyclic hydrocarbon structure, an ether group, an ester group, a carbonyl group, a carboxy group, or a combination thereof. is there. V is a group represented by any one of the above formulas (LC1-1) to (LC1-16).

In the above formula (AI), preferred examples of the substituent that the alkyl group represented by Rb ⁰ may have include a hydroxyl group and a halogen atom.

In the above formula (AI), examples of the halogen atom for Rb ⁰ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

Rb ⁰ is preferably a hydrogen atom or a methyl group.

In the above formula (AI), Ab is preferably a single bond or a linking group represented by -Ab ¹ -COO-. Ab ¹ is a linear or branched alkylene group or a monocyclic or polycyclic cycloalkylene group, preferably a methylene group, an ethylene group, a cyclohexylene group, an adamantylene group, or a norbornylene group.

  The structural unit containing a lactone group usually has an optical isomer, but any optical isomer may be used. One optical isomer may be used alone, or a plurality of optical isomers may be mixed and used. When one kind of optical isomer is mainly used, the optical purity (ee) thereof is preferably 90 or more, more preferably 95 or more.

  Examples of the structural unit containing a lactone group include a structural unit represented by the following formula.

In the above formula, R ^x is CH ₃ , CH ₂ OH or CF ₃ .

<Polar group>
[A] The polymer may have a polar group as another structure. [A] When the polymer has a polar group, the radiation-sensitive resin composition can improve adhesion to a substrate or the like. Examples of the structural unit having a polar group that is preferable in the present invention include a structural unit having an alicyclic hydrocarbon structure substituted with a polar group. The structural unit (I) and the structural unit (II) may be monocyclic or polycyclic. The structural unit etc. in which the alicyclic hydrocarbon structure of the ring has the polar group as a substituent also correspond to these.

  As the alicyclic hydrocarbon structure of the alicyclic hydrocarbon structure substituted with the polar group, an adamantyl group, a diamantyl group, and a norbornane group are preferable. The polar group is preferably a hydroxyl group or a cyano group.

  As the alicyclic hydrocarbon structure substituted with the polar group, partial structures represented by the following formulas (VIIa) to (VIId) are preferable.

In the formulas (VIIa) to (VIIc), R ^{2c to} R ^4c are each independently a hydrogen atom, a hydroxyl group, or a cyano group. However, at least one of R ^{2c to} R ^4c is a hydroxyl group or a cyano group. Preferably, one or two of R ^{2c to} R ^4c are hydroxyl groups, and the rest are hydrogen atoms. More preferably, two of R ^{2c to} R ^4c are hydroxyl groups and the rest are hydrogen atoms.

As the structural unit having a polar group, structural units having groups represented by general formulas (VIIa) to (VIId) are preferable, and R ^{13 ′ to} R in the above formula (II-AB1) or (II-AB2) are preferable. ^At least one of ^{16 ′} has a group represented by the above formula (VII) (for example, R ⁵ in —COOR ⁵ represents a group represented by general formulas (VIIa) to (VIId)), or the following Examples include structural units represented by general formulas (AIIa) to (AIId).

In the above formulas (AIIa) to (AIId), R ^1c is a hydrogen atom, a methyl group, a trifluoromethyl group or a hydroxymethyl group. R ^{2c to} R ^4c have the same ^meanings as the above formulas (VIIa) to (VIIc).

  Examples of the structural unit represented by the above formulas (AIIa) to (AIId) include a structural unit represented by the following formula.

<Other structural units>
[A] The polymer may have a structural unit represented by the following formula (VIII) as another structural unit.

In the above formula (VIII), Z ² is —O— or —N (R ⁴¹ ) —. R ⁴¹ is a hydrogen atom, a hydroxyl group, an alkyl group, or —OSO ₂ —R ⁴² . ^R42 is an alkyl group, a cycloalkyl group, or a camphor residue. The alkyl group of R ⁴¹ and R ⁴² may be substituted with a halogen atom (preferably a fluorine atom) or the like.

  Examples of the structural unit represented by the above formula (VIII) include a structural unit represented by the following formula.

  [A] The polymer may have a structural unit having 1 to 3 groups represented by the following formula (F1) as another structural unit. Thereby, the line edge roughness performance of the said radiation sensitive resin composition improves.

In the formula (F1), R ^{50 to} R ⁵⁵ are each independently a hydrogen atom, a fluorine atom, or an alkyl group. However, at least one of R ^{50 to} R ⁵⁵ is a fluorine atom or an alkyl group in which at least one hydrogen atom is substituted with a fluorine atom. R ^x is a hydrogen atom or an organic group (preferably an acid dissociable protecting group, an alkyl group, a cycloalkyl group, an acyl group, or an alkoxycarbonyl group).

In the above formula (F1), the alkyl group of R ^{50 to} R ⁵⁵ may be substituted with a halogen atom such as a fluorine atom or a cyano group, and has 1 to 3 carbon atoms such as a methyl group or a trifluoromethyl group. Alkyl groups are preferred.

In the above formula (F1), it is preferable that all of R ^{50 to} R ⁵⁵ are fluorine atoms.

In the above formula (F1), as the organic group represented by R ^x , an acid dissociable protecting group, an alkyl group, a cycloalkyl group, an acyl group, an alkylcarbonyl group, an alkoxycarbonyl group, which may have a substituent, An alkoxycarbonylmethyl group, an alkoxymethyl group, and a 1-alkoxyethyl group are preferable.

  As a preferred structural unit having a group represented by the above formula (F1), a structural unit represented by the following formula (F2) and the like can be mentioned.

In said formula (F2), ^Rx is a hydrogen atom, a halogen atom, or a C1-C4 alkyl group. F ^a is a single bond, a linear or branched alkylene group. F ^b is a monocyclic or polycyclic hydrocarbon group. F ^c is a single bond, a linear or branched alkylene group. F ¹ is a group represented by the general formula (F1). p ¹ is an integer of 1 to 3.

In the above formula (F2), preferred substituents that the alkyl group represented by R ^x may have include a hydroxyl group and a halogen atom.

In the above formula (F2), F ^a is preferably a single bond.

In the above formula (F2), the cyclic hydrocarbon group for F ^b is preferably a cyclopentyl group, a cyclohexyl group, or a norbornyl group.

In the above formula (F2), F ^c is preferably a single bond or a methylene group.

  Examples of the structural unit having a group represented by the formula (F1) include a structural unit represented by the following formula.

  The acid dissociable [A] polymer may further contain a structural unit that has an alicyclic hydrocarbon structure and does not exhibit acid dissociability as another structural unit. This can reduce the elution of low molecular components from the resist film to the immersion liquid during immersion exposure. Examples of such a structural unit include 1-adamantyl (meth) acrylate, tricyclodecanyl (meth) acrylate, cyclohexyl (meth) acrylate, and the like.

  [A] In addition to the above structural units, the polymer [A] is used for the purpose of adjusting dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and general resist characteristics such as resolution, heat resistance, and sensitivity. Other structural units can be contained.

  Due to these other structural units, the performance required for [A] polymer, in particular, (1) solubility in coating solvent, (2) film-forming property (glass transition temperature), (3) solubility in developer (4) Fine film adjustment (hydrophobicity), (5) Adhesion of unexposed part to substrate, (6) Dry etching resistance, etc. can be finely adjusted.

  Examples of such structural units include structural units corresponding to the following monomers.

  Examples of such a monomer include compounds having one addition polymerizable unsaturated bond such as acrylic acid esters, methacrylic acid esters, acrylamides, methacrylamides, allyl compounds, vinyl ethers, vinyl esters and the like. Can be mentioned.

  In addition, as long as it is an addition polymerizable unsaturated compound copolymerizable with monomers corresponding to the above various structural units, these may be copolymerized.

  [A] In the polymer, the content of each structural unit is the resist dry etching resistance, the standard developer suitability, the substrate adhesion, the resist profile, and the general required performance of the resist, such as resolution, heat resistance, and sensitivity. It is set appropriately to adjust.

[A] Preferred embodiments of the polymer include the following.
(1) One having a structural unit containing an alicyclic hydrocarbon structure represented by the above formulas (pI) to (pV) (side chain type). Preferably, it contains a (meth) acrylate structural unit having a structure of (pI) to (pV).
(2) Containing a structural unit represented by the above formula (II-AB) (main chain type). However, in (2), for example, the following can be further mentioned.
(3) A structural unit represented by the above formula (II-AB), a maleic anhydride derivative and a (meth) acrylate structure (hybrid type).

  [A] When the polymer is a polymer having an alicyclic hydrocarbon structure and an acid dissociable group, the content of the structural unit having an acid dissociable group in [A] polymer is 10 to 10 in all the structural units. 95 mol% is preferable, More preferably, it is 20-90 mol%, More preferably, it is 40-90 mol%.

  [A] When the polymer is a polymer having an acid dissociable group, the content of the structural unit having an acid dissociable group in the [A] polymer is preferably 10 to 95 mol% in all the structural units, More preferably, it is 20-90 mol%, More preferably, it is 40-90 mol%.

  [A] When the polymer is a polymer having an alicyclic hydrocarbon structure and an acid-dissociable group, the alicyclic hydrocarbon structure represented by the above formulas (pI) to (pV) in the [A] polymer. The content of the structural unit to be included is preferably 10 to 95 mol%, more preferably 20 to 90 mol%, still more preferably 40 to 90 mol%.

  [A] When the polymer is a polymer having an alicyclic hydrocarbon structure and an acid dissociable group, the content of the structural unit represented by the general formula (II-AB) in the [A] polymer is 10-60 mol% is preferable in a repeating structural unit, More preferably, it is 15-55 mol%, More preferably, it is 20-50 mol%.

[A] When the polymer is a polymer having an acid dissociable group, the content of the structural unit having a lactone structure in the [A] polymer is preferably 10 to 70 mol% in all the structural units. 65 mol% is more preferable.
[A] When the polymer is a polymer having an acid dissociable group, the content of the structural unit having a polar group in the polymer [A] is preferably 1 to 40 mol% in all repeating structural units. -30 mol% is more preferable, and 5-20 mol% is further more preferable.

  The content of the other structural units in the [A] polymer can be appropriately set according to the performance of the desired resist, but is generally represented by the above formulas (pI) to (pV). 99 mol% or less is preferable, more preferably 90 mol% or less, and more preferably 90 mol% or less, based on the total number of moles of the structural unit including the alicyclic hydrocarbon structure and the structural unit represented by the above formula (II-AB). Preferably it is 80 mol% or less.

  When the radiation sensitive resin composition of the present invention is for ArF exposure, the polymer preferably has no aromatic group from the viewpoint of transparency to ArF light.

  [A] When the polymer is a polymer having an alicyclic hydrocarbon structure and an acid-dissociable group, it is preferable that all of the structural units are composed of (meth) acrylate structural units. In this case, all of the structural units can be used as a methacrylate structural unit, all of the structural units are acrylate structural units, and all of the structural units can be any mixture of methacrylate structural units / acrylate structural units. The acrylate-based structural unit is preferably 50 mol% or less of the total structural units.

  [A] When the polymer is a polymer having an alicyclic hydrocarbon structure and an acid dissociable group, it is substituted with at least one of a (meth) acrylate structural unit having a lactone group, a hydroxyl group, and a cyano group A copolymer having three types of structural units, ie, a (meth) acrylate structural unit having an organic group and a (meth) acrylate structural unit having an acid dissociable group is preferable.

  [A] As a polymer, 20-60 mol% of structural units containing an alicyclic hydrocarbon structure represented by the above formulas (pI) to (pV), 20-60 mol% of structural units having a lactone group, polar groups A ternary copolymer containing 5 to 30% of structural units having an alicyclic hydrocarbon structure substituted with or a quaternary copolymer containing 0 to 20% of other structural units is preferred.

  Moreover, as a [A] polymer, 20-60 mol% of structural units which have an acid dissociable group represented by following formula (ARA-1)-(ARA-7), following formula (ARL-1)-( A copolymer having 20 to 60 mol% of a structural unit having a lactone group represented by ARL-6) and 5 to 20 mol% of a structural unit having an alicyclic hydrocarbon structure and not having acid dissociability is preferable. .

In the above formula, R ^xy1 represents a hydrogen atom or a methyl group. R ^xa1 and R ^xb1 are each independently a methyl group or an ethyl group. R ^xc1 is a hydrogen atom or a methyl group.

  [A] Resist composition for performing negative development using a developer containing an organic solvent by irradiating the polymer with KrF excimer laser light, electron beam, X-ray, high energy light (EUV, etc.) having a wavelength of 50 nm or less When used in the above, the [A] polymer preferably has a hydroxystyrene-based structural unit such as a structural unit based on hydroxystyrene. More preferably, it is a polymer having a hydroxystyrene structural unit and a structural unit having an acid dissociable group (hereinafter, also referred to as “hydroxystyrene acid dissociable polymer”). The structural unit having an acid dissociable group is preferably a hydroxystyrene structural unit protected with an acid dissociable group or an acid dissociable (meth) acrylic acid tertiary alkyl ester structural unit.

  As the hydroxystyrene-based structural unit protected with an acid-dissociable group, structural units such as 1-alkoxyethoxystyrene, t-butylcarbonyloxystyrene and the like are preferable. Examples of the alkyl group in the acid dissociable (meth) acrylic acid tertiary alkyl ester structural unit include a chain alkyl group and a monocyclic or polycyclic cyclic alkyl group. The acid dissociable (meth) acrylic acid tertiary alkyl ester structural unit is preferably t-butyl (meth) acrylate, 2-alkyl-2-adamantyl (meth) acrylate, 2- (1-adamantyl) -2. Examples include structural units such as -propyl (meth) acrylate, 1-alkyl-1-cyclohexyl (meth) acrylate, 1-alkyl-1-cyclopentyl (meth) acrylate, and the like.

  Hereinafter, specific examples of the hydroxystyrene-based acid dissociable polymer include polymers described in paragraph [0198] of Japanese Patent Application Laid-Open No. 2008-292975.

  The content of the acid dissociable group in the hydroxystyrene-based acid dissociable polymer is protected by the number of acid dissociable groups (B) in the hydroxystyrene-based acid dissociable polymer and a group capable of leaving with an acid. With no number of alkali-soluble groups (S), it is expressed as B / (B + S). The content is preferably 0.01 to 0.7, more preferably 0.05 to 0.50, and still more preferably 0.05 to 0.40.

  [A] polymer in this invention is compoundable according to a conventional method (for example, radical polymerization). For example, as a general synthesis method, a monomer polymerization method in which a monomer species and an initiator are dissolved in a solvent and the polymerization is performed by heating, and a solution of the monomer species and the initiator is dropped into the heating solvent over 1 to 10 hours. The dropping polymerization method is added, and the dropping polymerization method is preferable. Examples of the reaction solvent include ethers such as tetrahydrofuran, 1,4-dioxane and diisopropyl ether, ketones such as methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate, amide solvents such as dimethylformamide and dimethylacetamide, Furthermore, the solvent which melt | dissolves the composition of this invention like the below-mentioned propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, and cyclohexanone is mentioned. More preferably, polymerization is performed using the same solvent as the solvent used in the resist composition of the present invention. Thereby, generation | occurrence | production of the particle at the time of a preservation | save can be suppressed.

  The polymerization reaction is preferably performed in an inert gas atmosphere such as nitrogen or argon. As the polymerization initiator, a commercially available radical initiator (azo-based initiator, peroxide, etc.) is used to initiate the polymerization. As the radical initiator, an azo initiator is preferable, and an azo initiator having an ester group, a cyano group, or a carboxy group is preferable. Preferred initiators include azobisisobutyronitrile, azobisdimethylvaleronitrile, dimethyl 2,2'-azobis (2-methylpropionate) and the like. If desired, an initiator is added or added in portions, and after completion of the reaction, it is put into a solvent and a desired polymer is recovered by a method such as powder or solid recovery. The concentration of the reaction is 5 to 50% by mass, preferably 10 to 30% by mass. The reaction temperature is usually 10 ° C to 150 ° C, preferably 30 ° C to 120 ° C, more preferably 60-100 ° C.

  For purification, a method similar to that for the [F] polymer described later can be used, and a liquid-liquid extraction method for removing residual monomers and oligomer components by combining water washing and an appropriate solvent, those having a specific molecular weight or less. A purification method in a solution state such as ultrafiltration for extracting and removing only the resin, a reprecipitation method for removing residual monomers by coagulating the resin in the poor solvent by dropping the resin solution into the poor solvent, Ordinary methods such as a purification method in a solid state such as washing the resin slurry separated by filtration with a poor solvent can be applied.

  [A] The weight average molecular weight of the polymer is preferably from 1,000 to 200,000, more preferably from 3,000 to 20,000, and even more preferably from 5,000 to 200 as a polystyrene-converted value by the GPC method. 15,000. By setting the weight average molecular weight to 1,000 to 200,000, deterioration of heat resistance and dry etching resistance can be prevented, and developability is deteriorated, and viscosity is increased, resulting in deterioration of film forming property. Can be prevented.

  [A] Another particularly preferable form of the weight average molecular weight of the polymer is 3,000 to 14,000 in terms of polystyrene by GPC method. By setting the weight average molecular weight to 3,000 to 14,000, resist residues (hereinafter also referred to as “scum”) are particularly suppressed, and a better pattern can be formed.

  The degree of dispersion (molecular weight distribution) is usually 1 to 5, preferably 1 to 3, more preferably 1.2 to 3.0, and still more preferably 1.2 to 2.0. . The smaller the degree of dispersion, the better the resolution and the resist shape, the smoother the side wall of the resist pattern, and the better the roughness.

  In the radiation-sensitive resin composition of the present invention, the blending amount of the [A] polymer is preferably 50 to 99.9% by mass, more preferably 60 to 99.0% by mass in the total solid content. In the present invention, the resins may be used alone or in combination.

  [A] It is preferable that a polymer does not contain a fluorine atom and a silicon atom from a compatible viewpoint with the [F] polymer mentioned later.

<[B] Compound that generates acid upon irradiation>
The radiation-sensitive resin composition of the present invention preferably contains a compound that generates an acid upon irradiation with radiation (hereinafter also referred to as “[B] acid generator”).

  [B] As an acid generator, photocationic photoinitiator, photoinitiator of radical photopolymerization, dye photodecoloring agent, photochromic agent, or by irradiation with radiation used for micro resist Known compounds that generate acids and mixtures thereof can be appropriately selected and used.

  [B] Examples of the acid generator include diazonium salts, phosphonium salts, sulfonium salts, iodonium salts, imide sulfonates, oxime sulfonates, diazodisulfones, disulfones, and o-nitrobenzyl sulfonates.

  [B] As the acid generator, a group in which an acid is generated by irradiation of these radiations or a compound in which a compound is introduced into the main chain or side chain of the polymer can be used. Examples of these compounds include U.S. Pat. No. 3,849,137, German Patent 3,914,407, JP-A 63-26653, JP-A 55-164824, JP-A 62-69263, and JP-A 63-146038. And compounds described in JP-A-63-163452, JP-A-62-153853, JP-A-63-146029, and the like.

  Further, compounds that generate an acid by light described in US Pat. No. 3,777,778, European Patent 126712 and the like can also be used as the [B] acid generator in the present invention.

  Preferable [B] acid generators include compounds represented by the following formulas (ZI), (ZII), and (ZIII).

In the above formula (ZI), R ²⁰¹ , R ²⁰² and R ²⁰³ are each independently an organic group. X ⁻ is a non-nucleophilic anion, and preferably a sulfonate anion, a carboxylate anion, a bis (alkylsulfonyl) amide anion, a tris (alkylsulfonyl) methide anion, BF ₄ —, PF ₆ —, SbF ₆ — and the like. More preferably, it is an organic anion containing a carbon atom.

  A preferable organic anion includes an organic anion represented by the following formula.

In the above formula, R ^c1 is an organic group.

Examples of the organic group represented by R ^c1 include those having 1 to 30 carbon atoms, and preferably an optionally substituted aliphatic hydrocarbon group, aromatic group, or a plurality of these groups are a single bond, — _{O -, - CO 2 -,} - S -, - SO 3 -, - SO 2 N (R d1) - , and the like linked group linking group. R ^d1 represents a hydrogen atom or an alkyl group. R ^c3 , R ^c4 and R ^c5 are each independently an organic group. Preferred ^examples of the organic group for R ^c3 , R ^c4 , and R ^c5 include the same groups as the preferred organic group for R ^c1 , and most preferred is a perfluoroalkyl group having 1 to 4 carbon atoms. However, R ^c3 and R ^c4 may be bonded to form a ring. ^{Examples of the} group formed by combining R ^c3 and R ^c4 include an alkylene group and an arylene group. Preferably, it is a C2-C4 perfluoroalkylene group. The organic group of R ^c1 and R ^{c3 to} R ^c5 is particularly preferably an alkyl group substituted at the 1-position with a fluorine atom or a fluoroalkyl group, or a phenyl group substituted with a fluorine atom or a fluoroalkyl group. By having a fluorine atom or a fluoroalkyl group, the acidity of the acid generated by light irradiation is increased and the sensitivity is improved. Further, when R ^c3 and R ^c4 are bonded to form a ring, the acidity of the acid generated by light irradiation is increased, and the sensitivity is improved.

In the formula ^(ZI), the carbon number of the organic group as R ^{201, R 202} and ^{R 203} is generally from 1 to 30, preferably 1 to 20.
Two of R ^{201 to} R ²⁰³ may be bonded to form a ring structure, and the ring may contain an oxygen atom, a sulfur atom, an ester bond, an amide bond, or a carbonyl group. Examples of the group formed by combining two of R ^{201 to} R ²⁰³ include a cycloalkylene group (for example, a cyclobutylene group and a cyclopentylene group).
Specific examples of the organic group as R ²⁰¹ , R ²⁰² and R ²⁰³ include corresponding groups in the compounds (ZI-1), (ZI-2) and (ZI-3) described later.

A compound having a plurality of structures represented by the above formula (ZI) may be used. For example, at least one of ^R 201 ^{to R 203} of a compound represented by the formula (ZI) is a structure bonded to at least one of ^R 201 ^{to R 203} of another compound represented by formula (ZI) It may be a compound.

  Furthermore, examples of the compound represented by the formula (ZI) include compounds (ZI-1), (ZI-2), and (ZI-3) described below.

The compound (ZI-1) is at least one of the aryl groups ^R 201 ^{to R 203} in formula (ZI), arylsulfonium compound, i.e., a compound having arylsulfonium as a cation.
In the arylsulfonium compound, all of R ^{201 to} R ²⁰³ may be an aryl group, or a part of R ^{201 to} R ²⁰³ may be an aryl group, and the rest may be an alkyl group or a cycloalkyl group. Examples of the arylsulfonium compound include triarylsulfonium compounds, diarylalkylsulfonium compounds, aryldialkylsulfonium compounds, diarylcycloalkylsulfonium compounds, aryldicycloalkylsulfonium compounds, and the like.

  The aryl group of the arylsulfonium compound is preferably an aryl group such as a phenyl group or a naphthyl group, or a heteroaryl group such as an indole residue or a pyrrole residue, and more preferably a phenyl group or an indole residue. When the arylsulfonium compound has two or more aryl groups, the two or more aryl groups may be the same or different.

  The alkyl group that the arylsulfonium compound has as necessary is preferably a linear or branched alkyl group having 1 to 15 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, sec. -A butyl group, a t-butyl group, etc. can be mentioned. The cycloalkyl group that the arylsulfonium compound has as necessary is preferably a cycloalkyl group having 3 to 15 carbon atoms, and examples thereof include a cyclopropyl group, a cyclobutyl group, and a cyclohexyl group.

The aryl group, alkyl group, and cycloalkyl group of R ^{201 to} R ²⁰³ may have an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group, a halogen atom, a hydroxyl group, or a phenylthio group as a substituent. Among these, preferable substituents are a linear or branched alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, and a linear, branched or cyclic alkoxy group having 1 to 12 carbon atoms. More preferably, they are a C1-C4 alkyl group and a C1-C4 alkoxy group. Any one of the three R ^{201 to} R ²⁰³ described above may be present, or all three may be present. In the case where R ^{201 to} R ²⁰³ are an aryl group, the substituent is preferably bonded to the p-position of the aryl group.

The compound (ZI-2) is a compound in which R ^{201 to} R ²⁰³ in the above formula (ZI) are each independently an organic group not containing an aromatic ring. Here, the aromatic ring also includes an aromatic ring containing a hetero atom.

In the formula ^(ZI), the organic group having no aromatic ring as R 201 ^{to R 203} is a 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms.

In the above formula (ZI), R ^{201 to} R ²⁰³ are each independently preferably an alkyl group, a cycloalkyl group, an aryl group or a vinyl group, more preferably a linear, branched or cyclic 2- An oxoalkyl group or an alkoxycarbonylmethyl group, more preferably a linear or branched 2-oxoalkyl group.

In the above formula (ZI), the alkyl group represented by R ^{201 to} R ²⁰³ may be either linear or branched, preferably linear or branched having 1 to 10 carbon atoms. It is an alkyl group (for example, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group), and more preferably a linear or branched 2-oxoalkyl group or an alkoxycarbonylmethyl group.

In the above formula (ZI), the cycloalkyl group represented by R ^{201 to} R ²⁰³ is preferably a cycloalkyl group having 3 to 10 carbon atoms (cyclopentyl group, cyclohexyl group, norbornyl group). The cycloalkyl group as R ^{201 to} R ²⁰³ is preferably a cyclic 2-oxoalkyl group.

In the formula ^(ZI), linear represented by R 201 ^{to R 203,} a 2-oxoalkyl group branched or cyclic, said alkyl group, the 2-position of the cycloalkyl group> C = O at The group having is preferable.

In the above formula (ZI), the alkoxy group in the alkoxycarbonylmethyl group represented by R ^{201 to} R ²⁰³ is an alkoxy group having 1 to 5 carbon atoms (methoxy group, ethoxy group, propoxy group, butoxy group, pentoxy group). Is preferred.

In the above formula (ZI), R ^{201 to} R ²⁰³ may be substituted with a halogen atom, an alkoxy group having 1 to 5 carbon atoms, a hydroxyl group, a cyano group, or a nitro group.

  The compound (ZI-3) is a compound represented by the following formula (ZI-3) and is a compound having a phenacylsulfonium salt structure.

In the above formula (ZI-3), R ^{1c to} R ^5c each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, or a halogen atom. R ^6c and R ^7c are each independently a hydrogen atom, an alkyl group, or a cycloalkyl group. R ^x and R ^y are each independently an alkyl group, a cycloalkyl group, an allyl group, or a vinyl group. Any two or more of R ^{1c to} R ^7c , and R ^x and R ^y may be bonded to each other to form a ring structure, and this ring structure includes an oxygen atom, a sulfur atom, an ester bond, an amide Bonds may be included. Examples of the group formed by combining any two or more of R ^{1c to} R ^7c and R ^x and R ^y include a butylene group and a pentylene group. X ⁻ is a non-nucleophilic anion, and examples thereof include the same as the non-nucleophilic anion of X ⁻ in the above formula (ZI).

In the above formula (ZI-3), the alkyl group represented by R ^{1c to} R ^7c may be either linear or branched, for example, linear or branched alkyl having 1 to 20 carbon atoms. A straight chain having 1 to 12 carbon atoms such as a methyl group, an ethyl group, a linear or branched propyl group, a linear or branched butyl group, a linear or branched pentyl group, or the like; Branched alkyl groups are preferred.

In said formula (ZI-3), as a cycloalkyl group represented by R ^{< 1c} > -R <^7c> , C3-C8 cycloalkyl groups, such as a cyclopentyl group and a cyclohexyl group, are preferable.

In the above formula (ZI-3), the alkoxy group represented by R ^{1c to} R ^5c may be linear, branched or cyclic, and examples thereof include an alkoxy group having 1 to 10 carbon atoms. Alkoxy groups having 1 to 5 carbon atoms such as methoxy group, ethoxy group, linear or branched propoxy group, linear or branched butoxy group, linear or branched pentoxy group, cyclopentyloxy group, cyclohexyl C3-C8 cyclic alkoxy groups, such as an oxy group, are preferable.

In the above formula (ZI-3), any one of R ^{1c to} R ^5c is preferably a linear or branched alkyl group, a cycloalkyl group, or a linear, branched or cyclic alkoxy group, It is more preferable that the sum of the carbon numbers of R ^{1c to} R ^5c is 2 to 15. Thereby, the solvent solubility of the said radiation sensitive resin composition improves more, and generation | occurrence | production of a particle is suppressed at the time of a preservation | save.

In the above formula (ZI-3), examples of the alkyl group represented by R ^x and R ^y include the same alkyl groups represented by R ^{1c to} R ^7c . Of these, a linear or branched 2-oxoalkyl group and an alkoxycarbonylmethyl group are preferable.

In the above formula (ZI-3), examples of the cycloalkyl group represented by R ^x and R ^y include the same cycloalkyl groups represented by R ^{1c to} R ^7c . Of these, a cyclic 2-oxoalkyl group is preferred. Examples of the linear, branched, and cyclic 2-oxoalkyl group include the same alkyl groups represented by the above R ^{1c to} R ^7c . Of these, a group having> C═O at the 2-position of the cycloalkyl group is preferred.

The alkoxy group in the alkoxycarbonylmethyl group may be the same as the alkoxy group represented by R ^1c to R ^5c.

In the above formula (ZI-3), R ^x and R ^y are preferably an alkyl group having 4 or more carbon atoms, more preferably an alkyl group having 6 or more carbon atoms, and an alkyl group having 8 or more carbon atoms. More preferably.

In the above formulas (ZII) and (ZIII), R ^{204 to} R ²⁰⁷ are each independently an aryl group, an alkyl group, or a cycloalkyl group.

In the above formula ^(ZII), (ZIII), the aryl group of R 204 ^{to R 207,} a phenyl group, a naphthyl group are preferred, the phenyl group is more preferable.

In the above formulas (ZII) and (ZIII), the alkyl group represented by R ^{204 to} R ²⁰⁷ may be linear or branched, and may be a methyl group, an ethyl group, a propyl group, a butyl group, A linear or branched alkyl group having 1 to 10 carbon atoms such as a pentyl group is preferred.

In the above formula ^(ZII), (ZIII), the cycloalkyl group represented by R 204 ^{to R 207,} a cyclopentyl group, a cyclohexyl group, a cycloalkyl group having 3 to 10 carbon atoms such as norbornyl group.

In the above formulas (ZII) and (ZIII), R ^{204 to} R ²⁰⁷ may have a substituent. The R ²⁰⁴ to R ²⁰⁷ substituents which may have include an alkyl group having 1 to 15 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms, an aryl group having 6 to 15 carbon atoms, 1 to carbon atoms 15 alkoxy groups, halogen atoms, hydroxyl groups, phenylthio groups, and the like.

In the formula (ZII), X ⁻ is a non-nucleophilic anion, and examples thereof include the same as the non-nucleophilic anion of X ⁻ in the formula (ZI).

  Among the compounds that generate an acid upon irradiation with radiation, preferred compounds include those represented by the following formulas (ZIV), (ZV), and (ZVI).

In the above formulas (ZIV) to (ZVI), Ar ³ and Ar ⁴ each independently represents an aryl group. R ²⁰⁸ is an alkyl group or an aryl group. R ²⁰⁹ and R ²¹⁰ are each independently an alkyl group, an aryl group, or an electron-withdrawing group.

In the above formula (ZVI), R ²⁰⁹ is preferably an aryl group, R ²¹⁰ is preferably an electron-withdrawing group, more preferably a cyano group, and still more preferably a fluoroalkyl group. In the above formula (ZV), A represents an alkylene group, an alkenylene group or an arylene group.

  As the compound that generates an acid upon irradiation with radiation, compounds represented by the above formulas (ZI) to (ZIII) are preferable.

  [B] The acid generator contained in the radiation-sensitive resin composition is preferably a compound that generates an aliphatic sulfonic acid having a fluorine atom or a benzenesulfonic acid having a fluorine atom upon irradiation with radiation.

  [B] The acid generator preferably has a triphenylsulfonium structure.

  [B] The acid generator is preferably a triphenylsulfonium salt compound having an alkyl group or a cycloalkyl group not substituted with fluorine in the cation moiety.

  [B] Examples of particularly preferred acid generators include those described in paragraphs [0236] to [0241] of JP2008-292975A.

  [B] An acid generator can be used individually by 1 type or in combination of 2 or more types. When two or more types are used in combination, it is preferable to combine two types of compounds that generate two types of organic acids that differ in the total number of atoms excluding hydrogen atoms by two or more.

  [B] The content of the acid generator is preferably 0.1 to 20% by mass, more preferably 0.5 to 15% by mass, and 1 to 12% by mass based on the total solid content of the radiation-sensitive resin composition. Is more preferable.

<Solvent>
The radiation sensitive resin composition usually contains a solvent. Solvents that can be used in dissolving the above components and preparing the radiation-sensitive resin composition include, for example, alkylene glycol monoalkyl ether carboxylate, alkylene glycol monoalkyl ether, alkyl lactate ester, alkoxypropionic acid Examples thereof include organic solvents such as alkyl, cyclic lactones having 4 to 10 carbon atoms, monoketone compounds having 4 to 10 carbon atoms which may contain a ring, alkylene carbonate, alkyl alkoxyacetate, and alkyl pyruvate.

  Examples of alkylene glycol monoalkyl ether carboxylates include propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, propylene glycol monomethyl ether propionate, propylene glycol monoethyl ether pro Pionate, ethylene glycol monomethyl ether acetate, and ethylene glycol monoethyl ether acetate are preferred.

  As the alkylene glycol monoalkyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, ethylene glycol monomethyl ether, and ethylene glycol monoethyl ether are preferable.

  As alkyl lactate, methyl lactate, ethyl lactate, propyl lactate and butyl lactate are preferred.

  As the alkyl alkoxypropionate, ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, methyl 3-ethoxypropionate, and ethyl 3-methoxypropionate are preferable.

  Examples of the cyclic lactone having 4 to 10 carbon atoms include β-propiolactone, β-butyrolactone, γ-butyrolactone, α-methyl-γ-butyrolactone, β-methyl-γ-butyrolactone, γ-valerolactone, γ-caprolactone, γ-octanoic lactone and α-hydroxy-γ-butyrolactone are preferred.

  Examples of the monoketone compound having 4 to 10 carbon atoms which may contain a ring include 2-butanone, 3-methylbutanone, pinacolone, 2-pentanone, 3-pentanone, 3-methyl-2-pentanone, 4-methyl-2 -Pentanone, 2-methyl-3-pentanone, 4,4-dimethyl-2-pentanone, 2,4-dimethyl-3-pentanone, 2,2,4,4-tetramethyl-3-pentanone, 2-hexanone, 3-hexanone, 5-methyl-3-hexanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-methyl-3-heptanone, 5-methyl-3-heptanone, 2,6-dimethyl-4-heptanone, 2-octanone, 3-octanone, 2-nonanone, 3-nonanone, 5-nonanone, 2-decanone, 3-decanone, 4-decanone, 5-hexene-2 ON, 3-penten-2-one, cyclopentanone, 2-methylcyclopentanone, 3-methylcyclopentanone, 2,2-dimethylcyclopentanone, 2,4,4-trimethylcyclopentanone, cyclohexanone, 3-methylcyclohexanone, 4-methylcyclohexanone, 4-ethylcyclohexanone, 2,2-dimethylcyclohexanone, 2,6-dimethylcyclohexanone, 2,2,6-trimethylcyclohexanone, cycloheptanone, 2-methylcycloheptanone, 3 -Methylcycloheptanone is preferred.

  As the alkylene carbonate, propylene carbonate, vinylene carbonate, ethylene carbonate, and butylene carbonate are preferable.

  Examples of alkyl alkoxyacetate include 2-methoxyethyl acetate, 2-ethoxyethyl acetate, 2- (2-ethoxyethoxy) ethyl acetate, 3-methoxy-3-methylbutyl acetate, and 1-methoxy-2-acetic acid. Propyl is preferred.

  As the alkyl pyruvate, methyl pyruvate, ethyl pyruvate, and propyl pyruvate are preferable.

  As a solvent which can be preferably used, a solvent having a boiling point of 130 ° C. or higher under normal temperature and normal pressure can be mentioned. Specifically, cyclopentanone, γ-butyrolactone, cyclohexanone, ethyl lactate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, ethyl 3-ethoxypropionate, ethyl pyruvate, 2-ethoxyethyl acetate, acetic acid -2- (2-ethoxyethoxy) ethyl and propylene carbonate are mentioned. In the present invention, the above solvents may be used alone or in combination of two or more.

  In this invention, you may use the mixed solvent which mixed the solvent which contains a hydroxyl group in a structure, and the solvent which does not contain a hydroxyl group as an organic solvent.

  Examples of the solvent containing a hydroxyl group include ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, and ethyl lactate. Of these, propylene glycol monomethyl ether and ethyl lactate are more preferable.

  Examples of the solvent not containing a hydroxyl group include propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, butyl acetate, N-methylpyrrolidone, N, N-dimethylacetamide, dimethyl sulfoxide and the like. Can be mentioned. Among these, propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, and butyl acetate are more preferable, and propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, and 2-heptanone are more preferable. .

  The mixing ratio (mass) of the solvent containing a hydroxyl group and the solvent not containing a hydroxyl group is from 1/99 to 99/1, preferably from 10/90 to 90/10, more preferably from 20/80 to 60 /. 40. A mixed solvent containing 50% by mass or more of a solvent not containing a hydroxyl group is particularly preferable from the viewpoint of coating uniformity.

  Of these, the solvent that can be contained in the radiation-sensitive resin composition is preferably a mixed solvent of two or more containing propylene glycol monomethyl ether acetate.

<[F] Polymer having fluorine atom and / or silicon atom>
It is preferable that the radiation sensitive resin composition of this invention contains the [F] polymer which has a fluorine atom and / or a silicon atom. [F] The fluorine atom or silicon atom in the polymer may be contained in the polymer main chain or in the side chain.

  [F] As a partial structure having a fluorine atom, the polymer preferably has an alkyl group having a fluorine atom, a cycloalkyl group having a fluorine atom, or an aryl group having a fluorine atom.

  The alkyl group having a fluorine atom is a linear or branched alkyl group in which at least one hydrogen atom of the alkyl group is substituted with a fluorine atom, and may further have another substituent. As said alkyl group, C1-C10 is preferable and C1-C4 is more preferable.

  The cycloalkyl group having a fluorine atom is a monocyclic or polycyclic cycloalkyl group in which at least one hydrogen atom of the cycloalkyl group is substituted with a fluorine atom, and may have another substituent. Good.

  The aryl group having a fluorine atom is an aryl group in which at least one hydrogen atom of the aryl group is substituted with a fluorine atom, and may further have another substituent. Examples of the aryl group include a phenyl group and a naphthyl group.

  Specific examples of the alkyl group having a fluorine atom, a cycloalkyl group having a fluorine atom, or an aryl group having a fluorine atom are shown below.

In the above formulas (f-1) to (f-3), R ^{57 to} R ⁶⁸ are each independently a hydrogen atom, a fluorine atom or an alkyl group. Provided that at least one of R ^{57 to} R ⁶¹ , at least one of R ^{62 to} R ⁶⁴ and at least one of R ^{65 to} R ⁶⁸ are a fluorine atom or an alkyl group in which at least one hydrogen atom is substituted with a fluorine atom. It is.

All of R ^{57 to} R ⁶¹ in the formula (f-1) and R ^{65 to} R ⁶⁷ in the formula (f-3) are preferably fluorine atoms. R ⁶² , R ⁶³ and R ⁶⁴ in the formula (f-2) are preferably an alkyl group having 1 to 4 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom, More preferably, it is a 4 perfluoroalkyl group. R ⁶² and R ⁶³ may be bonded to each other to form a ring.

  Specific examples of the group represented by the formula (f-1) include a p-fluorophenyl group, a pentafluorophenyl group, and a 3,5-di (trifluoromethyl) phenyl group.

  Examples of the group represented by the formula (f-2) include trifluoroethyl group, pentafluoropropyl group, pentafluoroethyl group, heptafluorobutyl group, hexafluoroisopropyl group, heptafluoroisopropyl group, hexafluoro (2 -Methyl) isopropyl group, nonafluorobutyl group, octafluoroisobutyl group, nonafluorohexyl group, nonafluoro-t-butyl group, perfluoroisopentyl group, perfluorooctyl group, perfluoro (trimethyl) hexyl group, 2,2 , 3,3-tetrafluorocyclobutyl group, perfluorocyclohexyl group and the like. Among these, a hexafluoroisopropyl group, a heptafluoroisopropyl group, a hexafluoro (2-methyl) isopropyl group, an octafluoroisobutyl group, a nonafluoro-t-butyl group, and a perfluoroisopentyl group are preferable, and a hexafluoroisopropyl group, a hepta Even more preferred is a fluoroisopropyl group.

The group represented by the formula (f-3), for _{example, -C (CF 3) 2 OH} , -C (C 2 F 5) 2 OH, -C (CF 3) (CH 3) OH, - CH _(CF 3) OH and the like. Of these, -C _{(CF 3)} 2 OH is preferred.

  [F] The partial structure having a silicon atom in the polymer is preferably an alkylsilyl structure or a cyclic siloxane structure. Of the alkylsilyl structures, a trialkylsilyl group is preferred.

  Examples of the alkylsilyl structure or the cyclic siloxane structure include groups represented by the following formulas (CS-1) to (CS-3).

In the above formulas (CS-1) to (CS-3), R ^{12 to} R ²⁶ are each independently a linear or branched alkyl group (preferably having 1 to 20 carbon atoms) or a cycloalkyl group (preferably Is a carbon number of 3-20). L ^{3 to} L ⁵ are a single bond or a divalent linking group. n is an integer of 1-5.

In the formula (CS-1) ~ (CS -3), the alkyl group represented by R 12 ^{to R 26,} preferably an alkyl group having 1 to 20 carbon atoms. Moreover, as a cycloalkyl group represented by said R < ¹² > -R < ²⁶ >, a C3-C20 cycloalkyl group is preferable.

In the above formulas (CS-1) to (CS-3), examples of the divalent linking group represented by L ^{3 to} L ⁵ include an alkylene group, a phenyl group, an ether group, a thioether group, a carbonyl group, and an ester group. Amide group, urethane group, urea group or a group formed by combining these groups.

  Examples of the [F] polymer include polymers having at least one structural unit selected from the group consisting of structural units represented by the following formulas (CI) to (CV).

In the above formulas (CI) to (CV), R ^{1 to} R ³ are each independently a hydrogen atom, a fluorine atom, a linear or branched alkyl group having 1 to 4 carbon atoms, or A linear or branched fluorinated alkyl group having 1 to 4 carbon atoms. W ^{1 to} W ² are organic groups having a fluorine atom and / or a silicon atom. R ^{4 to} R ⁷ are each independently a hydrogen atom, a fluorine atom, a linear or branched alkyl group having 1 to 4 carbon atoms, or a linear or branched fluorinated group having 1 to 4 carbon atoms. It is an alkyl group. However, at least one of R ^{4 to} R ⁷ is a fluorine atom. R ⁴ and R ⁵ and R ⁶ and R ⁷ may be bonded to each other to form a ring. R ⁸ is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. R ⁹ is a linear or branched alkyl group having 1 to 4 carbon atoms, or a linear or branched fluorinated alkyl group having 1 to 4 carbon atoms. L < ¹ > -L < ² > is a single bond or a bivalent coupling group. Q is a monocyclic or polycyclic cycloaliphatic group, containing two bonded carbon atoms (C—C), and an atomic group for forming an alicyclic structure. R ³⁰ and R ³¹ are each independently a hydrogen atom or a fluorine atom. R ³² and R ³³ are each independently an alkyl group, a cycloalkyl group, a fluorinated alkyl group or a fluorinated cycloalkyl group. However, in the structural unit represented by the above formula (CV), at least one of R ³⁰ , R ³¹ , R ³² and R ³³ has a fluorine atom.

Examples of the divalent linking group represented by L ^{1 in the} above formula (CI) and L ² in the above formula (C-III) include L ^{3 in the} above formulas (CS-1) to (CS-3). It includes the same groups as the groups exemplified as the divalent linking group represented by ~L ^5.

  [F] The polymer preferably has a structural unit represented by the above formula (CI), and more preferably has a structural unit represented by the following formulas (C-Ia) to (C-Id). preferable.

In the above formulas (C-Ia) to (C-Id), R ¹⁰ and R ¹¹ are a hydrogen atom, a fluorine atom, a linear or branched alkyl group having 1 to 4 carbon atoms, or a carbon number 1 to 4 These are linear or branched fluorinated alkyl groups. W ^{3 to} W ⁶ are organic groups having a fluorine atom and / or a silicon atom.

In the above formulas (C-Ia) to (C-Id), when W ^{3 to} W ⁶ are organic groups having a fluorine atom, a fluorinated alkyl group having 1 to 20 carbon atoms or fluorine having 1 to 20 carbon atoms An alkyl ether group is preferable.

  Examples of the structural unit represented by the formula (C-Ia) include a structural unit represented by the following formula (3).

In said formula (3), R is a hydrogen atom, a methyl group, or a trifluoromethyl group. R ² is a hydrocarbon group of (m + 1) -valent C1-20, oxygen atoms at the ends of ^{R 3} side of the ^{R 2,} a sulfur atom, -NR'-, carbonyl group, -CO-O-or - Also includes a structure in which CO—NH— is bonded. R ′ is a hydrogen atom or a monovalent organic group. R ³ is a single bond, a divalent chain hydrocarbon group having 1 to 10 carbon atoms, or a divalent alicyclic group having 4 to 20 carbon atoms. X ² is a single bond or a divalent chain hydrocarbon group having 1 to 20 carbon atoms and having at least one fluorine atom. A is an oxygen atom, —NR ″ —, —CO—O— * or —SO ₂ —O— *. R ″ is a hydrogen atom or a monovalent organic group. Further, “*” represents a site that binds to R ⁴ . R ⁴ is a hydrogen atom or a monovalent organic group. m is an integer of 1-3. However, when m is 2 or 3, the plurality of R ³ , X ² , A and R ⁴ are independent of each other.

In the above formula (3), as the monovalent organic group represented by R ⁴ , an acid-dissociable group, a hydrocarbon group having 1 to 30 carbon atoms which may have a substituent, the following formula (W-1 ) To (W-4) and the like.

  Examples of the acid dissociable group include t-butoxycarbonyl group, tetrahydropyranyl group, tetrahydrofuranyl group, (thiotetrahydropyranylsulfanyl) methyl group, (thiotetrahydrofuranylsulfanyl) methyl group, alkoxy-substituted methyl group, alkylsulfanyl group. Examples include substituted methyl groups. In addition, as an alkoxyl group in an alkoxy substituted methyl group, a C1-C4 alkoxyl group etc. are mentioned, for example. Moreover, as an alkyl group in an alkylsulfanyl substituted methyl group, a C1-C4 alkyl group etc. are mentioned, for example. Moreover, as an acid dissociable group, group represented by the formula (Y-1) described in the term of the structural unit (IV) mentioned later may be sufficient. Among these, when A is an oxygen atom or —NR ″ — in the above formula (3), the acid dissociable group is preferably a t-butoxycarbonyl group or an alkoxy-substituted methyl group. Moreover, in Formula (3), when A is -CO-O-, it is preferable that it is group represented by Formula (Y-1) described in the term of the structural unit (IV) mentioned later.

In the above formula (3), examples of the group represented by R ⁴ include groups represented by the following formulas (W-1) to (W-4).

In Formula (W-1), Rf ¹ is a monovalent chain hydrocarbon group having 1 to 30 carbon atoms having at least one fluorine atom, or monovalent having 3 to 30 carbon atoms having at least one fluorine atom. Of the alicyclic group. In said formula (W-2) and (W-3), ^R41 is a substituent, and when two or more exist, they may be the same or different. m ₁ is an integer of 0 to 5. m ₂ is an integer of 0-4. In the formula ^{(W-4), R 42} and ^{R 43} are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon ^atoms, cycloaliphatic having 4 to 20 carbon atoms attached ^{R 42} and ^{R 43} are mutually A cyclic structure may be formed.

In the formula (W-2) and ^(W-3), examples of the substituent represented as ^{R 41, -R P1, -R P2} -O-R P1, -R P2 -CO-R P1, -R ^{P2 -CO-OR P1, -R P2} -O-CO-R P1, -R P2 -OH, -R P2 -CN, include -R P2 -COOH. R ^P1 is a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms, a monovalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms. And some or all of the hydrogen atoms of these groups may be substituted with fluorine atoms. ^RP2 is a single bond, a divalent chain saturated hydrocarbon group having 1 to 10 carbon atoms, a divalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or a divalent aromatic group having 6 to 30 carbon atoms. A hydrocarbon group or a group in which some or all of the hydrogen atoms of these groups are substituted with fluorine atoms. n _S is an integer of 0 to 3.

In addition, in the above formula (W-4), R ⁴² and R ⁴³ are bonded to each other and the alicyclic structure formed together with the carbon atoms to which they are bonded include a cyclopentyl group, a cyclopentylmethyl group, and 1- (1-cyclopentyl). Ethyl) group, 1- (2-cyclopentylethyl) group, cyclohexyl group, cyclohexylmethyl group, 1- (1-cyclohexylethyl) group, 1- (2-cyclohexylethyl group), cycloheptyl group, cycloheptylmethyl group, Examples include 1- (1-cycloheptylethyl) group, 1- (2-cycloheptylethyl) group, 2-norbornyl group and the like.

  Examples of the group represented by the formula (W-4) include a methyl group, an ethyl group, a 1-propyl group, a 2-propyl group, a 1-butyl group, a 2-butyl group, a 1-pentyl group, and 2-pentyl. Group, 3-pentyl group, 1- (2-methylbutyl) group, 1- (3-methylbutyl) group, 2- (3-methylbutyl) group, neopentyl group, 1-hexyl group, 2-hexyl group, 3-hexyl Group, 1- (2-methylpentyl) group, 1- (3-methylpentyl) group, 1- (4-methylpentyl) group, 2- (3-methylpentyl) group, 2- (4-methylpentyl) Group, 3- (2-methylpentyl) group and the like. Among these, a methyl group, an ethyl group, a 1-propyl group, a 2-propyl group, a 1-butyl group, and a 2-butyl group are preferable.

In the above formula (3), when m is 2 or 3, a plurality of R ³ may be bonded to the same carbon atom of R ² or may be bonded to different carbon atoms.

  Examples of the structural unit represented by the above formula (3) include structural units represented by the following formulas (3-1a) to (3-1c).

In the formula (3-1a) ~ (3-1c), R 5 is a divalent linear 1 to 20 carbon atoms, branched or cyclic, saturated or unsaturated hydrocarbon radical. The definitions of X ² , R ⁴ and m are the same as in the above formula (3). When m is 2 or 3, the plurality of X ² and R ⁴ are independent of each other.

  Examples of the monomer that gives the structural unit represented by the above formula (3) include compounds represented by the following formulas (3m-1) to (3m-6).

In said formula (3m-1)-(3m-6), R is synonymous with said formula (3). Each R ⁴ is independently a hydrogen atom or a monovalent organic group.

In the above formulas (CI), (C-III), and (C-Ia) to (C-Id), examples of the fluorinated alkyl group represented by W ^{1 to} W ⁶ include a trifluoroethyl group and pentafluoro group. Propyl group, hexafluoroisopropyl group, hexafluoro (2-methyl) isopropyl group, heptafluorobutyl group, heptafluoroisopropyl group, octafluoroisobutyl group, nonafluorohexyl group, nonafluoro-t-butyl group, perfluoroisopentyl group Perfluorooctyl group, perfluoro (trimethyl) hexyl group, and the like.

In the above formulas (CI), (C-III), and (C-Ia) to (C-Id), when W ^{1 to} W ⁶ are an organic group having a silicon atom, an alkylsilyl structure or a cyclic siloxane A structure is preferred. Specific examples include groups represented by the above formulas (CS-1) to (CS-3).

  Specific examples of the structural unit represented by the above formula (CI) are shown below.

  In said formula, X is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R is a hydrocarbon group having 1 to 4 carbon atoms.

[F] The polymer is preferably any polymer selected from the following (F-1) to (F-6).
(F-1) A polymer having a structural unit (a) having a fluoroalkyl group (preferably having 1 to 4 carbon atoms), more preferably a polymer having only a structural unit (a).
(F-2) A polymer having a structural unit (b) having a trialkylsilyl group or a cyclic siloxane structure, more preferably a polymer having only a structural unit (b).
(F-3) Structural unit (a) having a fluoroalkyl group (preferably having 1 to 4 carbon atoms), a branched alkyl group (preferably having 4 to 20 carbon atoms), a cycloalkyl group (preferably having 4 carbon atoms) To 20), a structural unit (c) having a branched alkenyl group (preferably having 4 to 20 carbon atoms), a cycloalkenyl group (preferably having 4 to 20 carbon atoms) or an aryl group (preferably having 4 to 20 carbon atoms). And more preferably a copolymer of the structural unit (a) and the structural unit (c).
(F-4) a structural unit (b) having a trialkylsilyl group or a cyclic siloxane structure, a branched alkyl group (preferably having 4 to 20 carbon atoms), a cycloalkyl group (preferably having 4 to 20 carbon atoms), And a structural unit (c) having a branched alkenyl group (preferably having 4 to 20 carbon atoms), a cycloalkenyl group (preferably having 4 to 20 carbon atoms) or an aryl group (preferably having 4 to 20 carbon atoms). Copolymer, more preferably a copolymer of the structural unit (b) and the structural unit (c).
(F-5) A polymer having a structural unit (a) having a fluoroalkyl group (preferably having 1 to 4 carbon atoms) and a structural unit (b) having a trialkylsilyl group or a cyclic siloxane structure, more preferably A copolymer of the structural unit (a) and the structural unit (b).
(F-6) a structural unit (a) having a fluoroalkyl group (preferably having 1 to 4 carbon atoms), a structural unit (b) having a trialkylsilyl group or a cyclic siloxane structure, and a branched alkyl group (preferably Is a C4-20), cycloalkyl group (preferably C4-20), branched alkenyl group (preferably C4-20), cycloalkenyl group (preferably C4-20) or aryl. A polymer having a structural unit (c) having a group (preferably having 4 to 20 carbon atoms), more preferably a copolymer of the structural unit (a), the structural unit (b) and the structural unit (c).

  Structural unit (c) having a branched alkyl group, a cycloalkyl group, a branched alkenyl group, a cycloalkenyl group, or an aryl group in the polymers (F-3), (F-4), and (F-6) ) Can be introduced with an appropriate functional group in consideration of hydrophilicity / hydrophobicity, interaction property, etc., but is a functional group having no polar group from the viewpoint of immersion liquid followability and receding contact angle. Is preferred.

  In the polymers (F-3), (F-4), and (F-6), the structural unit (a) having a fluoroalkyl group and / or the structural unit (b) having a trialkylsilyl group or a cyclic siloxane structure Is preferably 20 to 99 mol%.

  The receding contact angle is a contact angle measured when the contact line at the droplet-substrate interface recedes, and is useful for simulating the ease of movement of the droplet in a dynamic state. It is generally known that In simple terms, it can be defined as the contact angle when the droplet interface recedes when the droplet discharged from the needle tip is deposited on the substrate and then sucked into the needle again. It can be measured by using a contact angle measuring method generally called an expansion / contraction method. In the immersion exposure process, the immersion head needs to move on the wafer following the movement of the exposure head to scan the wafer at high speed to form the exposure pattern. In this case, the contact angle of the immersion liquid with respect to the resist film is important, and the resist is required to follow the high-speed scanning of the exposure head without remaining droplets.

  [F] The polymer is preferably a polymer having a structural unit represented by the following formula (Ia).

In the above formula (Ia), R ^f is a fluorine atom or an alkyl group in which at least one hydrogen atom is substituted with a fluorine atom. R ¹ is an alkyl group. R ² is a hydrogen atom or an alkyl group.

In the above formula (Ia), the alkyl group in which at least one hydrogen atom represented by R ^f is substituted with a fluorine atom preferably has 1 to 3 carbon atoms, and more preferably a trifluoromethyl group. The alkyl group represented by R ¹ in the above formula (Ia) is preferably a linear or branched alkyl group having 3 to 10 carbon atoms, and more preferably a branched alkyl group having 3 to 10 carbon atoms. R ² in the formula (Ia) is preferably a linear or branched alkyl group having 1 to 10 carbon atoms, and more preferably a linear or branched alkyl group having 3 to 10 carbon atoms.

  Examples of the structural unit represented by the formula (Ia) include a structural unit represented by the following formula.

  In the above formula, X is a fluorine atom or a trifluoromethyl group.

  Examples of the monomer that gives the structural unit represented by the formula (Ia) include compounds represented by the following formula (I).

In the above formula ^{(I), R f, R} 1 and ^{R 2} is as defined in the above formula (Ia).

  As the compound represented by the above formula (I), a commercially available product or a synthesized product may be used. In the case of synthesis, 2-trifluoromethylmethacrylic acid can be obtained by acidification and then esterification.

  The [F] polymer having a structural unit represented by the above formula (Ia) preferably further has a structural unit represented by the following formula (III).

In the above formula (III), R ⁴ is an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, a trialkylsilyl group, or a group having a cyclic siloxane structure. L ⁶ is a single bond or a divalent linking group.

In the above (III), the alkyl group represented by R ⁴ is preferably a linear or branched alkyl group having 3 to 20 carbon atoms.
As said cycloalkyl group, a C3-C20 cycloalkyl group is preferable.
As said alkenyl group, a C3-C20 alkenyl group is preferable.
As said cycloalkenyl group, a C3-C20 cycloalkenyl group is preferable.
As said trialkylsilyl group, a C3-C20 trialkylsilyl group is preferable.
The group having a cyclic siloxane structure is preferably a group having a cyclic siloxane structure having 3 to 20 carbon atoms.
The divalent linking group of L6 is preferably an alkylene group (preferably having 1 to 5 carbon atoms) or an oxy group.

  Specific examples of the [F] polymer having the structural unit represented by the above formula (Ia) include those described in paragraphs [0270] to [0275] of JP2008-292975A. .

  [F] The polymer is preferably a polymer having a structural unit represented by the following formula (II) and a structural unit represented by the following formula (III).

In the above formula, R ^f is a fluorine atom or an alkyl group in which at least one hydrogen atom is substituted with a fluorine atom. R ³ is an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, or a group formed by combining two or more thereof. R ⁴ is an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, a trialkylsilyl group, a group having a cyclic siloxane structure, or a group formed by combining two or more thereof. L ⁶ is a single bond or a divalent linking group. m is an integer of 0-100. n is an integer of 0-100.

A functional group can be introduced into the alkyl group, cycloalkyl group, alkenyl group, cycloalkenyl group, and trialkylsilyl group of R ³ in the above formula (II) and R ⁴ in the above formula (III). From the viewpoint of liquid followability, a functional group having no polar group is preferred, and unsubstituted is more preferred.

The alkyl group for R ³ and R ⁴ is preferably a linear or branched alkyl group having 3 to 20 carbon atoms.
As said cycloalkyl group, a C3-C20 cycloalkyl group is preferable.
As said alkenyl group, a C3-C20 alkenyl group is preferable.
As said cycloalkenyl group, a C3-C20 cycloalkenyl group is preferable.
L ⁶ in the above formula (III) is preferably a single bond, a methylene group, an ethylene group or an ether group.
As m in said formula (II), 30-70 are preferable and 40-60 are more preferable. As said n, 30-70 are preferable and 40-60 are more preferable.

  Specific examples of the [F] polymer having the structural unit represented by the above formula (II) and the structural unit represented by the above formula (III) include, for example, JP-A-2008-292975 [0291] to [0291] 0293] can be mentioned.

  [F] The polymer may have a structural unit represented by the following formula (VIII).

In the above formula (VIII), Z ² is —O— or —N (R ⁴¹ ) —. R ⁴¹ is a hydrogen atom, an alkyl group, or —OSO ₂ —R ⁴² . ^R42 is an alkyl group, a cycloalkyl group, or a camphor residue. The alkyl group of R ⁴¹ and R ⁴² may be substituted with a halogen atom (preferably a fluorine atom) or the like.

  [F] The polymer is preferably solid at room temperature (25 ° C.). Furthermore, the glass transition temperature (Tg) is preferably 50 to 200 ° C, more preferably 80 to 160 ° C.

  Being solid at room temperature (25 ° C.) means that the melting point is 25 ° C. or higher. In addition, the glass transition temperature (Tg) can be measured by scanning calorimetry, for example, the specific volume when the sample is heated once and cooled and then heated again at 5 ° C./min. It can be measured by analyzing the changed value.

  [F] The polymer is preferably stable to an acid and insoluble in an alkaline developer.

  [F] The polymer preferably has no alkali-soluble group from the viewpoint of affinity for the developer. [F] The total amount of structural units having an alkali-soluble group in the polymer is preferably 20 mol% or less, more preferably 0 to 10 mol, based on all structural units constituting the [F] polymer. %, And more preferably 0 to 5 mol%.

  Examples of alkali-soluble groups include phenolic hydroxyl groups, carboxylic acid groups, fluorinated alcohol groups, sulfonic acid groups, sulfonamido groups, sulfonylimide groups, (alkylsulfonyl) (alkylcarbonyl) methylene groups, (alkylsulfonyl) (alkylcarbonyl). ) Imide group, bis (alkylcarbonyl) methylene group, bis (alkylcarbonyl) imide group, bis (alkylsulfonyl) methylene group, bis (alkylsulfonyl) imide group, tris (alkylcarbonyl) methylene group, tris (alkylsulfonyl) methylene And a group having a group.

  Examples of the group that decomposes by the action of an alkali (alkaline developer) and increases the solubility in the alkali developer include a lactone group, an ester group, a sulfonamide group, an acid anhydride, and an acid imide group.

  Examples of the group that decomposes by the action of an acid and increases the solubility in a developer include the same groups as the acid dissociable groups in the [A] polymer.

  However, the structural unit represented by the following formula (pA-C) has no or very small decomposability due to the action of acid as compared with the acid dissociable group of the [A] polymer, and is substantially non-acid dissociated. It can be regarded as equivalent to gender.

In the above formula (pA-c), R ^p2 is a hydrocarbon group having a tertiary carbon atom bonded to an oxygen atom in the formula.

  When the [F] polymer has a silicon atom, the content of the silicon atom is preferably 2 to 50% by mass and more preferably 2 to 30% by mass with respect to the molecular weight of the [F] polymer. preferable. Moreover, it is preferable that the structural unit containing a silicon atom is 10-100 mass% in a [F] polymer, and it is more preferable that it is 20-100 mass%.

  When the [F] polymer has a fluorine atom, the content of the fluorine atom is preferably 5 to 80% by mass and more preferably 10 to 80% by mass with respect to the molecular weight of the [F] polymer. preferable. Moreover, it is preferable that the structural unit containing a fluorine atom is 10-100 mass% in a [F] polymer, and it is more preferable that it is 30-100 mass%.

  [F] The weight average molecular weight of the polymer in terms of standard polystyrene is preferably 1,000 to 100,000, more preferably 1,000 to 50,000, still more preferably 2,000 to 15,000, and particularly preferably. Is 3,000 to 15,000.

  [F] The polymer preferably has a residual monomer amount of 0 to 10% by mass, more preferably 0 to 5% by mass, and still more preferably 0 to 1% by mass. Further, from the viewpoint of resolution, resist shape, resist pattern side wall, roughness, etc., the molecular weight distribution (Mw / Mn) is preferably 1 to 5, more preferably 1 to 3, and still more preferably 1 to 1.5.

  It is preferable that the addition amount of the [F] polymer in a radiation sensitive resin composition is 0.1-20 mass% on the basis of the total solid of a radiation sensitive resin composition, 0.1-10 More preferably, it is mass%. More preferably, it is 0.1-5 mass%, 0.2-3.0 mass% is especially preferable, 0.3-2.0 mass% is the most preferable.

  The [F] polymer, like the [A] polymer, naturally has few impurities such as metals, but the residual monomer and oligomer components are not more than predetermined values, for example, 0.1% by mass or the like by HPLC. It is preferable that not only the sensitivity, resolution, process stability, pattern shape and the like as a resist can be further improved, but also a resist having no change over time such as foreign matter in liquid or sensitivity can be obtained.

  As the [F] polymer, various commercially available products can be used, and the polymer can be synthesized according to a conventional method (for example, radical polymerization). For example, as a general synthesis method, a monomer polymerization method in which a monomer species and an initiator are dissolved in a solvent and the polymerization is performed by heating, and a solution of the monomer species and the initiator is dropped into the heating solvent over 1 to 10 hours. The dropping polymerization method is added, and the dropping polymerization method is preferable. Examples of the reaction solvent include ethers such as tetrahydrofuran, 1,4-dioxane and diisopropyl ether, ketones such as methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate, amide solvents such as dimethylformamide and dimethylacetamide, Furthermore, the solvent which melt | dissolves the composition of this invention like the below-mentioned propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, and cyclohexanone is mentioned. More preferably, polymerization is performed using the same solvent as the solvent used in the resist composition of the present invention. Thereby, generation | occurrence | production of the particle at the time of a preservation | save can be suppressed.

  The polymerization reaction is preferably performed in an inert gas atmosphere such as nitrogen or argon. As the polymerization initiator, a commercially available radical initiator (azo-based initiator, peroxide, etc.) is used to initiate the polymerization. As the radical initiator, an azo initiator is preferable, and an azo initiator having an ester group, a cyano group, or a carboxy group is preferable. Preferred initiators include azobisisobutyronitrile, azobisdimethylvaleronitrile, dimethyl 2,2'-azobis (2-methylpropionate) and the like. A chain transfer agent can also be used as needed. The density | concentration of reaction is 5-50 mass% normally, Preferably it is 20-50 mass%, More preferably, it is 30-50 mass%. The reaction temperature is usually 10 ° C to 150 ° C, preferably 30 ° C to 120 ° C, more preferably 60-100 ° C.

  After completion of the reaction, the mixture is allowed to cool to room temperature and purified. Purification can be accomplished by a liquid-liquid extraction method that removes residual monomers and oligomer components by combining water and an appropriate solvent, and a purification method in a solution state such as ultrafiltration that extracts and removes only those having a specific molecular weight or less. , Reprecipitation method that removes residual monomer by coagulating resin in poor solvent by dripping resin solution into poor solvent and purification in solid state such as washing filtered resin slurry with poor solvent A normal method such as a method can be applied. For example, the resin is precipitated as a solid by contacting a solvent (poor solvent) in which the resin is hardly soluble or insoluble in a volume amount of 10 times or less, preferably 10 to 5 times that of the reaction solution.

  The solvent (precipitation or reprecipitation solvent) used in the precipitation or reprecipitation operation from the polymer solution may be a poor solvent for the polymer. For example, hydrocarbon (pentane, hexane, Aliphatic hydrocarbons such as heptane and octane; Cycloaliphatic hydrocarbons such as cyclohexane and methylcyclohexane; Aromatic hydrocarbons such as benzene, toluene and xylene), halogenated hydrocarbons (methylene chloride, chloroform, carbon tetrachloride, etc.) Halogenated aliphatic hydrocarbons; halogenated aromatic hydrocarbons such as chlorobenzene and dichlorobenzene), nitro compounds (nitromethane, nitroethane, etc.), nitriles (acetonitrile, benzonitrile, etc.), ethers (diethyl ether, diisopropyl ether, dimethoxyethane) Chain ethers such as tetrahydro Lan, cyclic ethers such as dioxane), ketones (acetone, methyl ethyl ketone, diisobutyl ketone, etc.), esters (ethyl acetate, butyl acetate, etc.), carbonates (dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, etc.), alcohols (methanol, Ethanol, propanol, isopropyl alcohol, butanol and the like), carboxylic acid (such as acetic acid), water, a mixed solvent containing these solvents, and the like. Among these, as the precipitation or reprecipitation solvent, a solvent containing at least an alcohol (particularly methanol or the like) or water is preferable. In such a solvent containing at least hydrocarbon, the ratio of alcohol (particularly methanol, etc.) to other solvent (eg, ester such as ethyl acetate, ether such as tetrahydrofuran) is, for example, the former / the latter (volume ratio). 25 ° C.) = 10/90 to 99/1, preferably the former / the latter (volume ratio; 25 ° C.) = 30/70 to 98/2, more preferably the former / the latter (volume ratio; 25 ° C.) = 50 / It is about 50 to 97/3.

  The amount of the precipitation or reprecipitation solvent can be appropriately selected in consideration of efficiency, yield, and the like, but is generally 100 to 10,000 parts by mass with respect to 100 parts by mass of the polymer solution, and 200 to 2, 000 parts by mass is preferable, and 300 to 1,000 parts by mass is more preferable.

  The nozzle diameter at the time of supplying the polymer solution to the precipitation or reprecipitation solvent (poor solvent) is preferably 4 mmφ or less (for example, 0.2 to 4 mmφ). Moreover, the supply speed (dropping speed) of the polymer solution into the poor solvent is, for example, about 0.1 to 10 m / second, preferably about 0.3 to 5 m / second, as the linear speed.

  The precipitation or reprecipitation operation is preferably performed with stirring. As a stirring blade used for stirring, for example, a desk turbine, a fan turbine (including a paddle), a curved blade turbine, an arrow blade turbine, a fiddler type, a bull margin type, an angled blade fan turbine, a propeller, a multistage type, an anchor type (or Horseshoe type), gate type, double ribbon, screw, etc. can be used. Stirring is preferably further performed for 10 minutes or more, particularly 20 minutes or more after the supply of the polymer solution. When the stirring time is short, the monomer content in the polymer particles may not be sufficiently reduced. Further, the polymer solution and the poor solvent can be mixed and stirred using a line mixer instead of the stirring blade.

  The temperature for precipitation or reprecipitation can be appropriately selected in consideration of efficiency and operability, but is usually about 0 to 50 ° C., preferably around room temperature (for example, about 20 to 35 ° C.). The precipitation or reprecipitation operation can be performed by a known method such as a batch method or a continuous method using a conventional mixing vessel such as a stirring tank.

  The precipitated or re-precipitated particulate polymer is usually subjected to conventional solid-liquid separation such as filtration and centrifugation, and dried before use. Filtration is performed using a solvent-resistant filter medium, preferably under pressure. Drying is performed at a temperature of about 30 to 100 ° C., preferably about 30 to 50 ° C. under normal pressure or reduced pressure (preferably under reduced pressure).

  In addition, once the resin is precipitated and separated, it may be dissolved again in a solvent, and the resin may be brought into contact with a hardly soluble or insoluble solvent. That is, after completion of the radical polymerization reaction, a solvent in which the polymer is hardly soluble or insoluble is brought into contact, the resin is precipitated (step a), the resin is separated from the solution (step b), and dissolved again in the solvent. (Step c), and then contact the resin solution A with a solvent in which the resin is hardly soluble or insoluble in a volume amount less than 10 times that of the resin solution A (preferably 5 times or less volume). This may be a method including precipitating a resin solid (step d) and separating the precipitated resin (step e). The solvent used in the preparation of the resin solution A can be the same solvent as the solvent that dissolves the monomer in the polymerization reaction, and may be the same as or different from the solvent used in the polymerization reaction.

<[C] Acid diffusion controller>
The radiation-sensitive resin composition of the present invention preferably contains a [C] acid diffusion controller in order to reduce changes in performance over time from exposure to heating. As the acid diffusion controller, a compound represented by the following formula (A) and a compound having a structure represented by formulas (B) to (E) are preferable.

In the above formulas (A) to (E), R ³⁰⁰ , R ³⁰¹ and R ³⁰² are each independently a hydrogen atom, an alkyl group (preferably having 1 to 20 carbon atoms), a cycloalkyl group (preferably having a carbon number). 3 to 20) or an aryl group (preferably having 6 to 20 carbon atoms). However, R ³⁰¹ and R ³⁰² may be bonded to each other to form a ring. R ^{303 to} R ³⁰⁶ are each independently an alkyl group having 1 to 20 carbon atoms.

  Regarding the alkyl group, the alkyl group having a substituent is preferably an aminoalkyl group having 1 to 20 carbon atoms, a hydroxyalkyl group having 1 to 20 carbon atoms, or a cyanoalkyl group having 1 to 20 carbon atoms. The alkyl groups in the above formulas (A) to (E) are more preferably unsubstituted.

  [C] As the acid diffusion controller, guanidine, aminopyrrolidine, pyrazole, pyrazoline, piperazine, aminomorpholine, aminoalkylmorpholine, piperidine and the like are preferable, imidazole structure, diazabicyclo structure, onium hydroxide structure, onium carboxylate structure, A compound having a trialkylamine structure, an aniline structure or a pyridine structure, an alkylamine derivative having a hydroxyl group and / or an ether bond, an aniline derivative having a hydroxyl group and / or an ether bond, and the like are more preferable.

  Examples of the compound having an imidazole structure include imidazole, 2,4,5-triphenylimidazole, and benzimidazole.

  Examples of the compound having a diazabicyclo structure include 1,4-diazabicyclo [2,2,2] octane, 1,5-diazabicyclo [4,3,0] non-5-ene, and 1,8-diazabicyclo [5,4. 0] Undecaker 7-ene and the like.

  Examples of the compound having an onium hydroxide structure include triarylsulfonium hydroxide, phenacylsulfonium hydroxide, sulfonium hydroxide having a 2-oxoalkyl group, specifically, triphenylsulfonium hydroxide, tris (t-butylphenyl). ) Sulfonium hydroxide, bis (t-butylphenyl) iodonium hydroxide, phenacylthiophenium hydroxide, 2-oxopropylthiophenium hydroxide, and the like.

  Examples of the compound having an onium carboxylate structure are compounds in which the anion portion of the compound having an onium hydroxide structure is converted to a carboxylate, and examples thereof include acetate, adamantane-1-carboxylate, and perfluoroalkylcarboxylate.

  Examples of the compound having a trialkylamine structure include tri (n-butyl) amine and tri (n-octyl) amine.

  Examples of the aniline compound include 2,6-diisopropylaniline, N, N-dimethylaniline, N, N-dibutylaniline, N, N-dihexylaniline and the like.

  Examples of the alkylamine derivative having a hydroxyl group and / or an ether bond include ethanolamine, diethanolamine, triethanolamine, and tris (methoxyethoxyethyl) amine.

  Examples of the aniline derivative having a hydroxyl group and / or an ether bond include N, N-bis (hydroxyethyl) aniline.

  [C] Preferred examples of the acid diffusion controller include an amine compound having a phenoxy group and an ammonium salt compound having a phenoxy group.

As the amine compound, primary, secondary, and tertiary amine compounds can be used, and an amine compound in which at least one alkyl group is bonded to a nitrogen atom is preferable. The amine compound is more preferably a tertiary amine compound. As long as at least one alkyl group (preferably having 1 to 20 carbon atoms) is bonded to a nitrogen atom, the amine compound has an cycloalkyl group (preferably having 3 to 20 carbon atoms) or an aryl group (preferably having 3 to 20 carbon atoms). Preferably C6-C12) may be bonded to a nitrogen atom. The amine compound preferably has an oxygen atom in the alkyl chain and an oxyalkylene group is formed. The number of oxyalkylene groups is one or more in the molecule, preferably 3 to 9, and more preferably 4 to 6. Among the oxyalkylene groups, an oxyethylene group (—CH ₂ CH ₂ O—) or an oxypropylene group (—CH (CH ₃ ) CH ₂ O— or —CH ₂ CH ₂ CH ₂ O—) is preferable, and more preferably oxy Ethylene group.

As the ammonium salt compound, primary, secondary, tertiary, and quaternary ammonium salt compounds can be used, and an ammonium salt compound in which at least one alkyl group is bonded to a nitrogen atom is preferable. As long as at least one alkyl group (preferably having 1 to 20 carbon atoms) is bonded to a nitrogen atom, the ammonium salt compound has a cycloalkyl group (preferably having 3 to 20 carbon atoms) or an aryl group in addition to the alkyl group. (Preferably having 6 to 12 carbon atoms) may be bonded to a nitrogen atom. The ammonium salt compound preferably has an oxygen atom in the alkyl chain and an oxyalkylene group is formed. The number of oxyalkylene groups is one or more in the molecule, preferably 3 to 9, and more preferably 4 to 6. Among the oxyalkylene groups, an oxyethylene group (—CH ₂ CH ₂ O—) or an oxypropylene group (—CH (CH ₃ ) CH ₂ O— or —CH ₂ CH ₂ CH ₂ O—) is preferable, and more preferably oxy Ethylene group.

  Examples of the anion of the ammonium salt compound include halogen atoms, sulfonates, borates, and phosphates. Among them, halogen atoms and sulfonates are preferable. As the halogen atom, chloride, bromide, and iodide are particularly preferable. As the sulfonate, an organic sulfonate having 1 to 20 carbon atoms is particularly preferable. Examples of the organic sulfonate include alkyl sulfonates having 1 to 20 carbon atoms and aryl sulfonates. The alkyl group of the alkyl sulfonate may have a substituent, and examples of the substituent include fluorine, chlorine, bromine, alkoxy groups, acyl groups, and aryl groups. Specific examples of the alkyl sulfonate include methane sulfonate, ethane sulfonate, butane sulfonate, hexane sulfonate, octane sulfonate, benzyl sulfonate, trifluoromethane sulfonate, pentafluoroethane sulfonate, and nonafluorobutane sulfonate. Examples of the aryl group of the aryl sulfonate include a benzene ring, a naphthalene ring, and an anthracene ring. The benzene ring, naphthalene ring and anthracene ring may have a substituent, and the substituent is preferably a linear or branched alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms. Specific examples of the linear or branched alkyl group and cycloalkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, i-butyl, t-butyl, n-hexyl, cyclohexyl and the like. Examples of the other substituent include an alkoxy group having 1 to 6 carbon atoms, a halogen atom, cyano, nitro, an acyl group, and an acyloxy group.

  The amine compound having a phenoxy group and the ammonium salt compound having a phenoxy group are those having a phenoxy group at the terminal opposite to the nitrogen atom of the alkyl group of the amine compound or ammonium salt compound. The phenoxy group may have a substituent. Examples of the substituent of the phenoxy group include an alkyl group, an alkoxy group, a halogen atom, a cyano group, a nitro group, a carboxy group, a carboxylic acid ester group, a sulfonic acid ester group, an aryl group, an aralkyl group, an acyloxy group, and an aryloxy group. Etc. The substitution position of the substituent may be any of the 2-6 positions. The number of substituents may be any in the range of 1 to 5.

It is preferable to have at least one oxyalkylene group between the phenoxy group and the nitrogen atom. The number of oxyalkylene groups is one or more in the molecule, preferably 3 to 9, and more preferably 4 to 6. Among the oxyalkylene groups, an oxyethylene group (—CH ₂ CH ₂ O—) or an oxypropylene group (—CH (CH ₃ ) CH ₂ O— or —CH ₂ CH ₂ CH ₂ O—) is preferable, and more preferably oxy Ethylene group.

  The amine compound having a phenoxy group is prepared by reacting a primary or secondary amine having a phenoxy group with a haloalkyl ether by heating, and then adding an aqueous solution of a strong base such as sodium hydroxide, potassium hydroxide or tetraalkylammonium. It can be obtained by extraction with an organic solvent such as ethyl acetate or chloroform. Alternatively, after reacting by heating a primary or secondary amine and a haloalkyl ether having a phenoxy group at the end, an aqueous solution of a strong base such as sodium hydroxide, potassium hydroxide, tetraalkylammonium, etc. is added, and then ethyl acetate, It can be obtained by extraction with an organic solvent such as chloroform.

  These [C] acid diffusion controllers may be used alone or in combination of two or more.

  [C] The usage-amount of an acid diffusion control body is 0.001-10 mass% normally based on solid content of a radiation sensitive resin composition, Preferably it is 0.01-5 mass%.

  The use ratio of the acid generator and the [C] acid diffusion controller in the composition is preferably acid generator / [C] acid diffusion controller (molar ratio) = 2.5 to 300. In other words, the molar ratio is preferably 2.5 or more from the viewpoint of sensitivity and resolution, and is preferably 300 or less from the viewpoint of suppressing the reduction in resolution due to the thickening of the resist pattern over time until post-exposure heat treatment.

<Surfactant>
The radiation-sensitive resin composition of the present invention preferably further contains a surfactant, and a fluorine-based and / or silicon-based surfactant (fluorine-based surfactant, silicon-based surfactant, fluorine atom and silicon atom) It is more preferable to contain any one or two or more surfactants having both.

  When the radiation-sensitive resin composition of the present invention contains the above surfactant, a resist pattern with good sensitivity and resolution and less adhesion and development defects can be obtained when using an exposure light source of 250 nm or less, particularly 220 nm or less. It becomes possible to give.

  Examples of the fluorine-based and / or silicon-based surfactant include, for example, JP-A No. 62-36663, JP-A No. 61-226746, JP-A No. 61-226745, JP-A No. 62-170950, JP 63-34540 A, JP 7-230165 A, JP 8-62834 A, JP 9-54432 A, JP 9-5988 A, JP 2002-277862 A, US Patent Nos. 5,405,720, 5,360,692, 5,529,881, 5,296,330, 5,436,098, 5,576,143, 5,294,511, 5,824,451 Surfactant can be mentioned, The following commercially available surfactant can also be used as it is.

  Examples of commercially available surfactants that can be used include F-top EF301 and EF303 (manufactured by Shin-Akita Kasei Co., Ltd.), Florard FC430, 431 and 4430 (manufactured by Sumitomo 3M), MegaFuck F171, F173, F176, F189, F113 and F110. , F177, F120, R08 (Dainippon Ink Chemical Co., Ltd.), Surflon S-382, SC101, 102, 103, 104, 105, 106 (Asahi Glass Co., Ltd.), Troisol S-366 (Troy Chemical Co., Ltd.), GF -300, GF-150 (manufactured by Toa Gosei Chemical Co., Ltd.), Surflon S-393 (manufactured by Seimi Chemical Co., Ltd.), EFtop EF121, EF122A, EF122B, RF122C, EF125M, EF135M, EF351, 352, EF801, EF802, EF601 (Gemco) Company ), PF636, PF656, PF6320, PF6520 (manufactured by OMNOVA), FTX-204D, 208G, 218G, 230G, 204D, 208D, 212D, 218, 222D (manufactured by Neos), etc. Mention may be made of activators. Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) can also be used as a silicon surfactant.

  In addition to the known surfactants described above, the surfactant is derived from a fluoroaliphatic compound produced by a telomerization method (also called telomer method) or an oligomerization method (also called oligomer method). A surfactant using a polymer having a fluoroaliphatic group can be used. The fluoroaliphatic compound can be synthesized by the method described in JP-A-2002-90991.

  As the polymer having a fluoroaliphatic group, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate and / or (poly (oxyalkylene)) methacrylate is preferable and distributed irregularly. Or may be block copolymerized. Examples of the poly (oxyalkylene) group include a poly (oxyethylene) group, a poly (oxypropylene) group, a poly (oxybutylene) group, and the like, and a poly (oxyethylene, oxypropylene, and oxyethylene group). A unit having different chain lengths in the same chain length, such as a block link) or poly (block link of oxyethylene and oxypropylene) may be used. Furthermore, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate (or methacrylate) is not only a binary copolymer but also a monomer having two or more different fluoroaliphatic groups, Further, it may be a ternary or higher copolymer obtained by simultaneously copolymerizing two or more different (poly (oxyalkylene)) acrylates (or methacrylates).

  Examples of commercially available surfactants include Megafac F178, F-470, F-473, F-475, F-476, and F-472 (Dainippon Ink & Chemicals, Inc.). Further, a copolymer of an acrylate (or methacrylate) having a C6F13 group and (poly (oxyalkylene)) acrylate (or methacrylate), an acrylate (or methacrylate) having a C3F7 group and (poly (oxyethylene)) acrylate (or And a copolymer of (methacrylate) and (poly (oxypropylene)) acrylate (or methacrylate).

  In the present invention, other surfactants other than fluorine-based and / or silicon-based surfactants can also be used. Specifically, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, polyoxyethylene alkyl ethers such as polyoxyethylene oleyl ether, polyoxyethylene octylphenol ether, polyoxyethylene nonylphenol ether, etc. Sorbitans such as polyoxyethylene alkyl allyl ethers, polyoxyethylene / polyoxypropylene block copolymers, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, sorbitan tristearate Fatty acid esters, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopal Te - DOO, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, may be mentioned polyoxyethylene sorbitan tristearate nonionic surfactants of polyoxyethylene sorbitan fatty acid esters such as such.

  These surfactants may be used alone or in combination of two or more.

  The amount of the surfactant used is preferably 0.01 to 10% by mass, more preferably 0.1 to 5% by mass, based on the total amount of the radiation-sensitive resin composition (excluding the solvent).

<Carboxylic acid onium salt>
The radiation sensitive resin composition in the present invention may contain a carboxylic acid onium salt. Examples of the carboxylic acid onium salt include a carboxylic acid sulfonium salt, a carboxylic acid iodonium salt, and a carboxylic acid ammonium salt. In particular, as the carboxylic acid onium salt, iodonium salts and sulfonium salts are preferable. Furthermore, in this invention, it is preferable that the carboxylate residue of carboxylic acid onium salt does not contain an aromatic group and a carbon-carbon double bond. More preferred anion moieties include linear, branched, monocyclic or polycyclic alkyl carboxylic acid anions having 1 to 30 carbon atoms. More preferably, an anion of a carboxylic acid in which part or all of these alkyl groups are fluorine-substituted is used. These alkyl chains may contain an oxygen atom. This ensures transparency with respect to light of 220 nm or less, improves sensitivity and resolution, and improves density dependency and exposure margin.

  Fluorine-substituted carboxylic acid anions include fluoroacetic acid, difluoroacetic acid, trifluoroacetic acid, pentafluoropropionic acid, heptafluorobutyric acid, nonafluoropentanoic acid, perfluorododecanoic acid, perfluorotridecanoic acid, perfluorocyclohexanecarboxylic acid, 2 , 2-bistrifluoromethylpropionic acid anion and the like.

  These carboxylic acid onium salts can be synthesized by reacting sulfonium hydroxide, iodonium hydroxide, ammonium hydroxide and carboxylic acid with silver oxide in a suitable solvent.

  The content of the carboxylic acid onium salt in the composition is generally from 0.1 to 20% by mass, preferably from 0.5 to 10% by mass, more preferably from 1 to 20% by mass, based on the total solid content of the composition. 7% by mass.

<Other additives>
In the resist composition of the present invention, a dye, a plasticizer, a photosensitizer, a light absorber, an alkali-soluble resin, a dissolution inhibitor, and a compound that promotes solubility in a developer (for example, a molecular weight of 1000) may be added to the resist composition of the present invention. The following phenol compounds, alicyclic compounds having a carboxy group, or aliphatic compounds) can be included.

  Such phenol compounds having a molecular weight of 1000 or less can be easily obtained by those skilled in the art with reference to the methods described in, for example, JP-A-4-1222938, JP-A-2-28531, US Pat. No. 4,916,210, European Patent 219294, and the like. Can be synthesized.

  Specific examples of alicyclic or aliphatic compounds having a carboxy group include carboxylic acid derivatives having a steroid structure such as cholic acid, deoxycholic acid, lithocholic acid, adamantane carboxylic acid derivatives, adamantane dicarboxylic acid, cyclohexane carboxylic acid, cyclohexane Examples thereof include, but are not limited to, dicarboxylic acids.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples. In the examples and comparative examples, “parts” and “%” are based on mass unless otherwise specified. Moreover, the measuring method of various physical-property values and the evaluation method of various characteristics are shown below.

[Weight average molecular weight (Mw) and number average molecular weight (Mn)]
A gel based on monodisperse polystyrene using GPC columns (2 G2000HXL, 1 G3000HXL, 1 G4000HXL) manufactured by Tosoh Corporation, with flow rate: 1.0 ml / min, elution solvent: tetrahydrofuran, column temperature: 40 ° C. It was measured by permeation chromatography (GPC). The degree of dispersion (Mw / Mn) was calculated from the measurement results.

[ ¹³ C-NMR]
^{The 13} C-NMR analysis was measured using “JNM-EX270” manufactured by JEOL Ltd.

<[A] Synthesis of polymer>
The monomer compounds used in the synthesis of [A] polymer and [F] polymer described below are shown below.

Synthesis Example 1 Synthesis of Polymer (A-1) 8.5 g (35 mol%) of Compound (M-1), 5.4 g (15 mol%) of Compound (M-4), and Compound (M-6) 16 0.1 g (50 mol%) was dissolved in 2-butanone 60 g, and a monomer solution charged with 1.2 g of dimethylazobisisobutyronitrile was prepared. On the other hand, a 200 mL three-necked flask charged with 30 g of 2-butanone was purged with nitrogen for 30 minutes, and then the reaction kettle was heated to 80 ° C. with stirring, and the monomer solution prepared in advance was added using a dropping funnel. It was added dropwise over time. The polymerization start was carried out for 6 hours with the start of dropping as the polymerization start time. After the completion of the polymerization, the polymerization solution was cooled with water to 30 ° C. or less, poured into 600 g of methanol, and the precipitated white powder was filtered off. The filtered white powder was washed twice with 150 g of methanol in the form of a slurry and then filtered again and dried at 50 ° C. for 17 hours to obtain a white powder copolymer. Mw of the obtained copolymer was 6,800, Mw / Mn was 1.38, and the yield was 84.5%. As a result of ¹³ C-NMR analysis, the content of the structural unit derived from the compound (M-1) / the structural unit derived from the compound (M-4) / the structural unit derived from the compound (M-6) is mol. % And was 35.2 / 14.8 / 50.0. This copolymer is referred to as “polymer (A-1)”. Table 1 shows the types of compounds used in Synthesis Example 1 and the formulation. Further, Table 2 shows the measurement results of Mw, Mw / Mn, yield, and the ratio of the structural unit derived from each monomer in the copolymer.

[Synthesis Examples 2 to 18] Synthesis of Polymers (A-2) to (A-18) Synthesis Example 1 except that the monomers shown in Table 1 were used in the formulation shown in Table 1. A copolymer was prepared by the same method. In addition, Table 2 shows the Mw, Mw / Mn, yield, and ratio of the structural unit derived from each monomer in the copolymer. Let each copolymer be a polymer (A-2)-(A-18).

[Synthesis Example 19]
Compound (M-1) 50 mol%, Compound (M-14) 10 mol%, Compound (M-6) 40 mol%, As a polymerization initiator, 2,2'-azobisisobutyronitrile 5 mol% A monomer solution dissolved in 60 g of methyl ethyl ketone was prepared. In addition, mol% of each monomer compound is a ratio with respect to all the monomer compounds, and mol% of the polymerization initiator is a ratio with respect to the total number of moles of all the monomer compounds and the polymerization initiator. The total mass of the monomer compounds was adjusted to 30 g. Meanwhile, 30 g of methyl ethyl ketone was added to a 500 mL three-necked flask equipped with a thermometer and a dropping funnel, and a nitrogen barge was performed for 30 minutes. Then, it heated so that it might become 80 degreeC, stirring the inside of a flask with a magnetic stirrer. Next, the monomer solution was dropped into the flask over 3 hours using a dropping funnel. The dripping start was set as the polymerization reaction start time, and the polymerization reaction was carried out for 6 hours. Then, it cooled until it became 30 degrees C or less, and obtained the polymerization solution. This polymerization solution was put into 600 g of methanol, and the precipitated white powder was separated by filtration. The filtered white powder was washed twice with 120 g of methanol as a slurry, washed, filtered and dried at 50 ° C. for 17 hours to obtain a white powder polymer (A-19) (yield). Rate: 71.5%). As a result of ¹³ C-NMR analysis, structural unit derived from compound (M-1) in polymer (A-19): structural unit derived from compound (M-14): inclusion of structural unit derived from compound (M-6) The rate (mol%) was 47.8: 11: 41.2, respectively. Moreover, Mw of the polymer (A-19) was 5,900, and Mw / Mn was 1.42.

[Synthetic Examples 20 to 34] Synthesis of Polymers (A-20) to (A-34) Synthetic Examples 19 and 19 except that the types of monomers shown in Table 5 were used in the formulation shown in Table 3. A copolymer was prepared by the same method. Table 4 shows the Mw, Mw / Mn, yield, and measurement results of the proportion of structural units derived from each monomer in the copolymer. Let each copolymer be resin (A-20)-(A-34).

<Synthesis of [F] polymer>
[Synthesis Example 35] Polymer (F-1)
37.4 g (40 mol%) of the compound (M-8) and 62.6 g (60 mol%) of the compound (M-9) were dissolved in 100 g of 2-butanone to obtain a dissolved solution. 4.8 g of dimethyl-2,2′-azobisisobutyrate was added to the resulting dissolved solution to prepare a monomer solution.
Next, a 500 mL three-necked flask charged with 100 g of 2-butanone was purged with nitrogen for 30 minutes. After purging with nitrogen, the reactor was heated to 80 ° C. with stirring, and the monomer solution prepared in advance was dropped into the three-necked flask over 3 hours using a dropping funnel. A polymerization solution was obtained by carrying out the polymerization reaction for 6 hours with the start of dropping as the polymerization start time. After completion of the polymerization, the polymerization solution was cooled with water and cooled to 30 ° C. or lower, and charged into 800 g of methanol / water = 19/1 to precipitate a white substance. After removing the supernatant solution, it was washed with 800 g of methanol / water = 19/1. Thereafter, the solvent was replaced with propylene glycol monomethyl ether acetate to obtain a polymer solution. (47.0 g in terms of solid content, yield 47%). This copolymer has a molecular weight (Mw) of 4,000, an Mw / Mn of 1.35, and as a result of ¹³ C-NMR analysis, a structural unit derived from the compound (M-8): the compound (M-9) The content rate (mol%) of the derived structural unit was 40.2: 59.8. Let the copolymer obtained by this synthesis example be a polymer (F-1).

Synthesis Example 36 Synthesis of Polymer (F-2) 35.8 g (70 mol%) of the compound (M-2) and 14.2 g (30 mol%) of the compound (M-18) were dissolved in 100 g of methyl ethyl ketone. As a polymerization initiator, 3.2 g of dimethyl 2,2′-azobisisobutyrate was added to prepare a monomer solution. A 500 mL three-necked flask containing 100 g of methyl ethyl ketone was purged with nitrogen for 30 minutes, then heated to 80 ° C. with stirring, and the prepared monomer solution was added dropwise over 3 hours using a dropping funnel. The dripping start was set as the polymerization reaction start time, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization reaction, the polymerization solution is cooled with water and cooled to 30 ° C. or lower, washed with 825 g of a methanol / methyl ethyl ketone / hexane = 2/1/8 (mass ratio) mixed solution, and then solvent with propylene glycol monomethyl ether acetate. Substitution was carried out to obtain a polymer (F-2) solution (38.0 g in terms of solid content, yield 76.0%). As a result of ¹³ C-NMR analysis, the structural unit derived from the compound (M-2) in the polymer (F-2): the content (mol%) of the structural unit derived from the compound (M-18) is 70.2: 29.8. Moreover, Mw of the polymer (F-2) was 7,000, and Mw / Mn was 1.40.

[Synthesis Example 37] Synthesis of Polymer (F-3) 25.5 g (60 mol%) of Compound (M-12), 15.0 g (25 mol%) of Compound (M-19) and Compound (M-20) 9.5 g (15 mol%) was dissolved in 100 g of methyl ethyl ketone, and 1.8 g of 2,2′-azobisisobutyronitrile was added as a polymerization initiator to prepare a monomer solution. A 500 mL three-necked flask containing 100 g of methyl ethyl ketone was purged with nitrogen for 30 minutes, then heated to 80 ° C. with stirring, and the prepared monomer solution was added dropwise over 3 hours using a dropping funnel. The dripping start was set as the polymerization reaction start time, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization reaction, the polymerization solution is cooled with water and cooled to 30 ° C. or lower, washed with 825 g of a methanol / methyl ethyl ketone / hexane = 2/1/8 (mass ratio) mixed solution, and then solvent with propylene glycol monomethyl ether acetate. Substitution was carried out to obtain a polymer (F-3) solution (35.0 g in terms of solid content, yield 70.0%). As a result of ¹³ C-NMR analysis, structural unit derived from compound (M-12) in polymer (F-3): structural unit derived from compound (M-19): inclusion of structural unit derived from compound (M-20) The ratio (mol%) was 63.2: 21.4: 15.4. Moreover, Mw of the polymer (F-3) was 6,200, and Mw / Mn was 1.55.

[Synthesis Example 38] Synthesis of Polymer (F-4) 27.1 g (60 mol%) of Compound (M-8), 14.0 g (25 mol%) of Compound (M-19) and Compound (M-20) 8.9 g (15 mol%) was dissolved in 100 g of methyl ethyl ketone, and 1.7 g of 2,2′-azobisisobutyronitrile was added as a polymerization initiator to prepare a monomer solution. A 500 mL three-necked flask containing 100 g of methyl ethyl ketone was purged with nitrogen for 30 minutes, then heated to 80 ° C. with stirring, and the prepared monomer solution was added dropwise over 3 hours using a dropping funnel. The dripping start was set as the polymerization reaction start time, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization reaction, the polymerization solution is cooled with water and cooled to 30 ° C. or lower, washed with 825 g of a methanol / methyl ethyl ketone / hexane = 2/1/8 (mass ratio) mixed solution, and then solvent with propylene glycol monomethyl ether acetate. Substitution was carried out to obtain a polymer (F-4) solution (33.2 g in terms of solid content, yield 66.4%). As a result of ¹³ C-NMR analysis, structural unit derived from compound (M-8) in polymer (F-4): structural unit derived from compound (M-19): inclusion of structural unit derived from compound (M-20) The ratio (mol%) was 62.2: 22.4: 15.4. Moreover, Mw of the polymer (F-4) was 6,700, and Mw / Mn was 1.58.

<Preparation of radiation-sensitive resin composition>
[Example 1]
The [B] acid generator, [C] acid diffusion controller and solvent used for the preparation of the radiation sensitive resin composition are shown below.

[B] Acid generators (B-1) to (B-3): compounds represented by the following formulae

[C] Acid diffusion control agents (C-1) to (C-8): compounds represented by the following formulae

Solvent (E-1): Propylene glycol monomethyl ether acetate (E-2): Cyclohexanone (E-3): γ-butyrolactone

[Example 1]
100 parts by mass of polymer (A-1), 10.8 parts by mass of acid generator (B-1), 4.3 parts by mass of acid diffusion controller (C-1), 2 parts by mass of polymer (F-1) Then, 2185 parts by mass of the solvent (E-1), 935 parts by mass of the solvent (E-2), and 30 parts by mass of the solvent (E-3) were mixed to prepare a radiation sensitive resin composition.

[Examples 2-16 and Comparative Examples 1-2]
A radiation-sensitive resin composition was prepared in the same manner as in Example 1 except that the formulation shown in Table 5 was used.

[Example 17]
100 parts by mass of polymer (A-4), 10 parts by mass of acid generator (B-1), 2.1 parts by mass of compound (C-1), 3 parts by mass of polymer (F-2), solvent (E- 1) 2200 mass parts, solvent (E-2) 950 mass parts, and solvent (E-3) 30 mass parts were mixed, and the radiation sensitive resin composition was prepared.

[Examples 18 to 36 and Preparation Examples 1 and 2]
A radiation sensitive resin composition was prepared in the same manner as in Example 17 except that the formulation shown in Table 6 was used.

<Evaluation of radiation-sensitive resin composition>
About the radiation sensitive resin composition of Examples 1-16 and Comparative Examples 1-2, various evaluation was performed as follows. These evaluation results are shown in Table 5.

[Sensitivity (mJ / cm ² )]
When exposure is performed with an ArF light source, a silicon wafer having an ARC29 (Nissan Chemical Industry Co., Ltd.) film with a film thickness of 77 nm formed on the wafer surface is used, and the prepared radiation-sensitive resin composition solution is cleaned on the substrate. It was applied by spin coating using ACT8 (manufactured by Tokyo Electron), and PB was performed on the hot plate under the conditions shown in Table 5 to form a resist film having a thickness of 0.10 μm. The formed resist film was exposed using an ArF excimer laser exposure apparatus “S306C” (numerical aperture: 0.78) manufactured by Nikon Corporation through a mask pattern having a reduced projection exposure pattern with a diameter of 0.10 μm. After carrying out PEB under the conditions shown in Table 5, development was carried out with a butyl acetate solvent at 23 ° C. for 30 seconds, rinse treatment with 4 methyl 2-pentanol solvent was carried out for 10 seconds, and then drying to obtain a negative resist pattern (1H / 1S). At this time, the exposure amount that gave a hole size of 0.10 μm in diameter was the optimum exposure amount, and this optimum exposure amount was taken as the sensitivity.

[Evaluation of cross-sectional shape of pattern]
The cross-sectional shape of the 0.10 μm hole pattern in the above sensitivity measurement was observed with “S-4800” manufactured by Hitachi High-Technologies Corporation, and the line width Lb in the middle of the resist pattern and the line width La in the upper part of the film were observed. Was evaluated as “A (good)” when it was in the range of 0.9 ≦ (La / Lb) ≦ 1.1, and “B (defective)” when it was out of the range.

[Evaluation of roundness]
At the optimum exposure dose, the hole pattern of 0.10 μm formed on the resist film on the substrate is observed from the top of the pattern using a length measuring SEM (manufactured by Hitachi, Ltd., model number “S9380”), and the diameter is set at an arbitrary point. When the measurement variation was expressed by 3σ, the case of 9.0 nm or less was evaluated as “A (good)”, and the case of being over 9.0 nm was evaluated as “B (defect)” .

[Evaluation of resolution]
In the evaluation of [sensitivity], “A ⁺ (best)” when the minimum hole size obtained when the exposure amount is increased is 50 nm or less, and “A (good) when it is in the range of 70 to 50 nm. In the case of 70 nm or more, it was evaluated as “B (defect)”.

  As can be seen from Table 5, the radiation-sensitive resin composition containing a resin having a carboxy group-containing structural unit content of 10 mol% or less based on the total structural units is excellent in pattern shape, circularity and resolution performance. A resist pattern can be formed. On the other hand, the radiation-sensitive resin composition containing a resin in which the content of the structural unit having a carboxy group in Comparative Examples 1 and 2 exceeds 10 mol% with respect to the total structural units is improved in shape, circularity, and resolution performance. There is room for.

  Various evaluation was performed as follows as Examples 37-95 and Comparative Examples 3-8 using the radiation sensitive resin composition (J-1 to J-22). These evaluation results are shown in Tables 7 to 9.

<Pattern formation>
Using a silicon wafer on which an ARC66 (BREWER SCIENCE) lower-layer antireflection film having a thickness of 105 nm was formed as a substrate, the radiation-sensitive resin compositions prepared in Examples 17 to 36 and Preparation Examples 1 and 2 were respectively used as substrates. On top of this, a clean track ACT12 (Tokyo Electron) was applied by spin coating, and PB was performed on a hot plate at 80 ° C. for 60 seconds to form a resist film having a thickness of 0.10 μm. The formed resist film was subjected to reduced projection exposure through a mask pattern and immersion water using an ArF immersion exposure apparatus (S610C, Nikon Corporation, numerical aperture 1.30). Next, after performing PEB for 60 seconds at the PEB temperature (° C.) described in Table 7, development was performed at 23 ° C. for 30 seconds using methyl amyl ketone as a developer, and then 4-methyl-2-pentanol (MIBC). The substrate was rinsed for 10 seconds and then dried to form a negative resist pattern. Note that the exposure amount that would result in a hole pattern with a diameter of 0.060 μm on the wafer after reduced projection was taken as the optimum exposure amount, and this optimum exposure amount was taken as sensitivity (mJ / cm ² ). Table 8 shows the results of using n-butyl acetate developer as the developer, and Table 9 shows the same evaluation results using anisole developer. The following evaluation results are also shown in Tables 7 to 9.

[DOF (Depth Of Focus; depth of focus (nm))]
Using a silicon wafer on which an ARC66 (BREWER SCIENCE) underlayer antireflection film having a thickness of 105 nm was formed, each radiation-sensitive resin composition was spin-coated on each substrate using a clean track ACT12 (Tokyo Electron). This was applied and PB was performed on a hot plate at 80 ° C. for 60 seconds to form a resist film having a thickness of 0.10 μm. The formed resist film was subjected to reduced projection exposure through a mask pattern and immersion water using an ArF immersion exposure apparatus (S610C, Nikon Corporation, numerical aperture 1.30). With respect to the obtained hole pattern, the exposure amount represented by the sensitivity described in the columns of methyl amyl ketone developer of Table 7, n-butyl acetate developer of Table 8, and anisole developer of Table 9, the following pitch size and The DOF to be the pattern size was obtained, and the common DOF area was calculated as the common DOF. For DOD, a CD value that falls within a range of ± 10% of the target pattern size is defined as a focus margin and calculated as a DOF value.
Pitch size and pattern size: 0.060 μm hole 0.104 μm pitch, 0.060 μm hole 0.800 μm pitch Note that the dimension measurement of the hole pattern was observed from the top of the pattern using a length measuring SEM (Hitachi High-Technologies Corporation, CG4000). did.

[Evaluation of roundness]
Using the ArF immersion exposure apparatus (S610C, Nikon Corporation, numerical aperture 1.30) on the resist film formed according to the method described in the pattern formation method, the optimum exposure amount (sensitivity) described in Tables 7 to 9, A 0.060 μm hole 0.104 μm pitch hole pattern formed using a developer was observed from above the pattern using a length measurement SEM (Hitachi High-Technologies Corporation, CG4000). The hole diameter is measured at an arbitrary 24 points, and the measurement variation is evaluated by 3σ. When it is 0.002 μm or less, it is judged as “A (good)”, and when it exceeds 0.002 μm, “B (bad) I decided.

[Evaluation of resolution]
Using the mask pattern in which the pitch size of the pattern after reduced projection exposure was 0.104 μm, reduced projection exposure was performed through immersion water, and the minimum size of holes obtained when the exposure amount was increased was measured. When the minimum hole size was 0.045 μm or less, it was judged as “(A) good”, and when it exceeded 0.045 μm, it was judged as “(B) bad”.

[Evaluation of cross-sectional shape]
At the optimum exposure amount represented by the sensitivity described in Tables 7 to 9, the cross-sectional shape of the 0.060 μm hole pattern formed on the resist film on the substrate was observed (Hitachi High-Technologies Corporation, S-4800), and the resist The line width Lb in the middle of the pattern and the line width La at the top of the film are measured, and the case where it is within the range of 0.9 ≦ (La / Lb) ≦ 1.1 is evaluated as “(A) good”, The case outside the range was evaluated as “(B) defective”.

<Formation of contact hole pattern by multiple exposure>
[Example 96]
Using the composition described in Example 1 above, exposure is performed through a mask having a target size of 100 nm line / 200 nm pitch (100 nm 1L1S) to form a resist pattern latent image, and then orthogonal to the resist pattern latent image. As described above, a negative resist pattern was formed in the same manner as in the above [sensitivity] evaluation except that the target size was exposed through a mask of 100 nm line / 100 nm pitch (100 nm1L1S). It was confirmed that a hole pattern (1H / 1S) having a diameter of 100 nm can be formed with an optimum exposure amount.

[Examples 97 to 98 and Comparative Examples 9 to 10]
An antireflection film forming agent (Burewer Science, trade name “ARC66”) was spin-coated on a 12-inch silicon wafer using “CLEAN TRACK Lithius Pro i” (Tokyo Electron), and then at 205 ° C. Pre-baking (PB) was performed for 60 seconds to form a lower antireflection film having a thickness of 105 nm. Spin a radiation sensitive resin composition of J-2, J-5, J-18, J-21, and J-22 on this substrate using “CLEAN TRACK Lithius Pro i” (manufactured by Tokyo Electron). After coating and pre-baking (PB) at 90 ° C. for 60 seconds, the resist layer having a thickness of 100 nm was formed by cooling at 23 ° C. for 30 seconds. Next, using an ArF immersion exposure apparatus (trade name “NSR-S610C”, manufactured by Nikon Seiki Co., Ltd.), the first through a line and space pattern mask under the optical conditions of NA = 1.3 and dipole Y Reduced projection exposure is performed at the sensitivity described in Table 10, and then, the line described in Table 10 is set so that the line intersects with the exposed portion where the first exposure is performed under the conditions of NA = 1.3 and dipole X. A second reduced projection exposure was performed with sensitivity. After exposure, post exposure bake (PEB) is performed for 60 seconds at a temperature shown in Table 10 on a hot plate of the trade name “CLEAN TRACK Lithius Pro i”, and after cooling at 23 ° C. for 30 seconds, methyl amyl ketone Was developed as a developing solution for 30 seconds and rinsed with 4-methyl-2-pentanol for 7 seconds. By spin-drying by shaking off at 2,000 rpm for 15 seconds, a resist pattern having a 40 nm hole / 80 nm pitch was formed, and the following evaluation was performed. In addition, the exposure amount which becomes a hole pattern with a diameter of 40 nm on the wafer after the reduced projection was defined as the optimum exposure amount, and this optimum exposure amount was defined as the sensitivity (mJ / cm ² ). The same evaluation was performed using n-butyl acetate developer and anisole developer as the developer. The results are shown in Table 10.

[Evaluation of roundness]
A resist pattern having a 40 nm hole / 80 nm pitch was observed from above the pattern using a length measurement SEM (Hitachi High-Technologies Corporation, CG4000). The hole diameter is measured at an arbitrary 24 points, and the measurement variation is evaluated by 3σ. When it is 0.002 μm or less, it is judged as “A (good)”, and when it exceeds 0.002 μm, “B (bad) I decided.

[Evaluation of cross-sectional shape]
The cross-sectional shape of the resist pattern with 40 nm holes / 80 nm pitch was observed (Hitachi High-Technologies Corporation, S-4800), and the line width Lb in the middle of the resist pattern and the line width La at the upper part of the film were measured. The case of (La / Lb) ≦ 1.1 was evaluated as “A (good)”, and the case of being out of the range was evaluated as “B (defective)”.

  As can be seen from Table 10, in any case used as a methyl amyl ketone developer, an n-butyl acetate developer and an anisole developer, the content of the structural unit having a carboxy group is 10 moles relative to the total structural unit. % Of the radiation-sensitive resin composition containing a resin of not more than 1% can form a resist pattern excellent in pattern shape, circularity and resolution performance. On the other hand, the radiation-sensitive resin composition containing a resin in which the content of the structural unit having a carboxy group in Comparative Examples 9 and 10 exceeds 10 mol% with respect to the total structural units is improved in shape, circularity, and resolution performance. There is room for.

  The radiation-sensitive resin composition of the present invention can be suitably used for photoresists that require increasingly finer line widths of resist patterns in the future.

Claims (22)

(1) A step of applying a radiation-sensitive resin composition on a substrate to form a resist film,
(2) A method of forming a pattern including a hole or a trench having a step of exposing the resist film, and (3) a step of developing the exposed resist film with a developer,
The radiation sensitive resin composition is
[A] containing a polymer whose content of structural units having a carboxy group is 10 mol% or less and whose polarity is increased by the action of an acid,
The pattern forming method, wherein the developer contains an organic solvent.   [A] The pattern forming method according to claim 1, wherein the polymer has a monocyclic or polycyclic alicyclic hydrocarbon structure. [A] The pattern forming method according to claim 1 or 2, wherein the polymer has an acid dissociable group represented by the following formula (1a).

(In formula (1a), R ^p11 is a linear, branched or cyclic monovalent hydrocarbon group having 1 to 20 carbon atoms. N is an integer of 1 to 4.)   [A] The pattern forming method according to claim 1, wherein the polymer has a structural unit containing a lactone group. The pattern formation method according to claim 4, wherein the lactone group is one or more groups selected from the group consisting of groups represented by the following formulas (LC1-1) to (LC1-16).

(Wherein, _{n 2,} the .rb ² is an integer of 0 to 4, when it .n ₂ is 2 or more substituents, the plurality of Rb ² may be the same or different, a plurality of Rb ² may combine with each other to form a ring.)   The lactone group is a group consisting of groups represented by the above formulas (LC1-1), (LC1-4), (LC1-5), (LC1-6), (LC1-13) and (LC1-14). The pattern forming method according to claim 4, wherein the pattern forming method is one or more selected from the group. The lactone group is a group represented by the above formula (LCI -4), and _{n 2} in the formula (LCI -4) is, according to claim 4 is zero, according to claim 5 or claim 6 Pattern forming method.   The pattern forming method according to claim 1, wherein the step (2) is performed a plurality of times.   9. The pattern forming method according to claim 1, further comprising: (2 ′) heating the exposed resist film after the step (2) and before the step (3).   The pattern forming method according to claim 9, wherein the step (2 ′) is performed a plurality of times.   The organic solvent contained in the developer is at least one organic solvent selected from the group consisting of ketone solvents, ester solvents, alcohol solvents, amide solvents, and ether solvents. The pattern forming method according to any one of 10. The pattern forming method according to claim 1, wherein the organic solvent contained in the developer is represented by the following formula (1).

(In Formula (1), R and R ′ are each independently a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxyl group, an alkoxycarbonyl group, a carboxy group, a hydroxyl group, a cyano group, or a halogen atom. , R and R ′ may be bonded to each other to form a ring.) The pattern formation method according to any one of claims 1 to 12, wherein the organic solvent contained in the developer is represented by the following formula (2).

(In formula (2), R ″ and R ″ ″ each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxyl group, an alkoxycarbonyl group, a carboxy group, a hydroxyl group, a cyano group, or a halogen atom. (However, R ″ and R ″ ″ may be bonded to each other to form a ring. R ′ ″ is an alkylene group or a cycloalkylene group.)   The pattern formation method according to claim 12, wherein the organic solvent represented by the formula (1) is alkyl acetate.   The pattern formation method according to claim 14, wherein the alkyl acetate is butyl acetate.   The pattern forming method according to any one of claims 1 to 15, wherein a content of the organic solvent not containing a halogen atom in the developer is 60% by mass or more. After the step (3),
(4) The pattern forming method according to any one of claims 1 to 16, further comprising a step of washing the developed resist film with a rinse liquid containing an organic solvent.   The organic solvent contained in the rinsing liquid is at least one organic solvent selected from the group consisting of hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents, and ether solvents. Item 18. The pattern forming method according to Item 17.   The pattern forming method according to claim 17 or 18, wherein the organic solvent contained in the rinse liquid is an alcohol solvent.   The pattern formation method according to claim 19, wherein the alcohol solvent is a linear, branched or cyclic monovalent alcohol solvent having 6 to 8 carbon atoms.   The pattern formation method according to any one of claims 17 to 20, wherein a moisture content of the rinse liquid is 30% by mass or less.   The radiation sensitive resin composition used for the pattern formation method of any one of Claim 1 to Claim 21.