JP2010286618A - Pattern forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pattern forming method useful for forming a fine pattern. <P>SOLUTION: The pattern forming method includes: (i) a process for forming a resist pattern 3 on a support in which a lower-layer film 2 is laminated on a substrate 1; (ii) a process for applying an inversion pattern forming material to the support on which the resist pattern 3 has been formed to form a film 4 for pattern inversion; and (iii) a process for removing the resist pattern 3 by etching to form an inversion pattern 4a. The inversion pattern forming material contains titanium-containing polymer (T) which is formed by the dehydro-condensation of a hydrolysate of tetra-alkoxy titanium. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a pattern forming method including a step of forming a reverse pattern.

A technique (pattern formation technique) for forming a fine pattern on a support and etching the lower layer of the pattern by using this as a mask is widely adopted for the creation of IC devices in the semiconductor field. Has attracted attention.
The fine pattern is usually made of an organic material, and is formed by a technique such as a lithography method or a nanoimprint method. For example, in a lithography method, a resist film made of a resist composition containing a base component such as a resin is formed on a support such as a substrate, and the resist film is selectively irradiated with radiation such as light or an electron beam. A step of forming a resist pattern having a predetermined shape on the resist film is performed by performing exposure and developing. And a semiconductor element etc. are manufactured through the process of processing a board | substrate by an etching using the said resist pattern as a mask.

In recent years, the miniaturization of patterns has been rapidly progressed by the advancement of lithography technology.
As a technique for miniaturizing a resist pattern, generally, the wavelength of an exposure light source is shortened. Specifically, conventionally, ultraviolet rays typified by g-line and i-line have been used, but now mass production of semiconductor elements using KrF excimer laser and ArF excimer laser has been started. Lithography using an ArF excimer laser enables pattern formation with a resolution of 45 nm. In addition, in order to further improve the resolution, studies have been made on F ₂ excimer lasers, electron beams, EUV (extreme ultraviolet rays), X-rays, and the like having shorter wavelengths than these excimer lasers.
Resist materials are required to have lithography characteristics such as sensitivity to these exposure light sources and resolution capable of reproducing a pattern with fine dimensions. As a resist material that satisfies such requirements, a chemically amplified resist composition containing an acid generator that generates an acid upon exposure is used. In the chemically amplified resist composition, a base material component whose solubility in an alkali developer is changed by the action of an acid generated from the acid generator is usually blended together with the acid generator. A resist material in which the exposed portion changes to a property that dissolves in the developer is referred to as a positive type, and a resist material that changes to a property in which the exposed portion does not dissolve in the developer is referred to as a negative type. For example, as a base material component of a positive chemically amplified resist, a material whose solubility in an alkaline developer is increased by the action of an acid is used (for example, see Patent Document 1). Resins are mainly used as the base component of the chemically amplified resist composition.

One of the pattern forming techniques proposed in recent years is a pattern inversion method (for example, Patent Documents 2 to 5). In the pattern inversion method, for example, a resist pattern is formed on a substrate provided with a lower layer film, the resist pattern is coated with a silicon (Si) -containing film, and then the upper portion of the Si-containing film is removed by etching or the like. The resist pattern is exposed and the resist pattern is etched by oxygen plasma or the like. As a result, the resist pattern is removed, and a pattern (reversal pattern) in which the image of the initially formed resist pattern is reversed is formed on the Si-containing film.
When the Si-containing film on which the reverse pattern is formed is used as an etching mask and the lower layer film on the lower side is etched, the reverse pattern is transferred to the lower layer film, and a pattern is formed on the substrate.
Conventionally, as a method for forming a Si-containing film in the pattern reversal method, a SOG (spin-on-glass) method or a method of applying an organic solvent solution of a silicon-containing polymer such as polysiloxane is used. The SOG method is generally a method for forming a film containing SiO ₂ as a main component by applying a solution (SOG solution) in which a silicon compound is dissolved in an organic solvent and performing a heat treatment.

JP 2003-241385 A JP-A-5-267253 JP 2002-110510 A JP 2004-363371 A JP 2008-287176 A

When forming a space pattern or a hole pattern using a resist composition, especially in the case of a positive type, compared to the case of forming a line pattern or a dot pattern, it is forced to form a pattern under a weak light incident intensity. Also, the contrast of the intensity of light incident on the unexposed area is small. Therefore, it is easy to limit the pattern forming ability such as resolution and lithography margin (for example, margin to exposure amount and depth of focus (EL margin and DOF margin), pattern shape verticality, etc.) in forming a resist pattern, and a fine pattern is formed. Tend to be difficult to do.
In order to form such a space pattern or hole pattern with high resolution, it is conceivable to use the pattern inversion method as described above.
However, miniaturization of the pattern usually accompanies miniaturization of the resist film. For example, when a resist pattern having a pattern dimension of 100 nm or less is to be formed, the thickness of the resist film is usually 150 nm or less. When trying to form a reversal pattern using a fine resist pattern formed on such a thin resist film, it is difficult to form a fine reversal pattern satisfactorily with conventional techniques.
For example, when an inorganic film (SiO ₂ film) is to be formed as a Si-containing film, the gap between the resist patterns is narrow, so that the material for forming the SiO ₂ film cannot be embedded well in the gap portion. There's a problem. Further, in the case of the SOG method, it is necessary to heat at a high temperature when forming a film, which may adversely affect the shape of the resist pattern. In addition, as the resist film becomes thinner, the thickness of the Si-containing film needs to be reduced, but in the case of the Si-containing film formed using a silicon-containing polymer, etching is performed as compared with the inorganic film (SiO ₂ film). The resistance is low, and a part of the resist pattern or the lower layer film is damaged during etching, or the Si-containing film disappears before the etching is completed.
These problems cause a shape defect of the inverted pattern remaining after etching. Since pattern shape defects may adversely affect the formation of semiconductor elements and the like, alternative techniques that can solve such problems are required.
This invention is made | formed in view of the said situation, Comprising: It aims at provision of the pattern formation method useful for formation of a fine pattern.

The first aspect of the present invention for solving the above problems is a step (i) of forming a resist pattern on a support using a resist composition;
(Ii) forming a pattern reversal film by applying a reversal pattern forming material on the support on which the resist pattern is formed;
Removing the resist pattern by etching to form a reverse pattern (iii),
The pattern forming method is characterized in that the reverse pattern forming material contains a titanium-containing polymer (T) formed by dehydration condensation of a hydrolyzate of tetraalkoxy titanium.

Here, in the present specification and claims, “exposure” is a concept including general irradiation of radiation.
“Constituent unit” means a monomer unit (monomer unit) constituting a resin component (polymer, copolymer).
Unless otherwise specified, the “alkyl group” includes linear, branched and cyclic monovalent saturated hydrocarbon groups.
Unless otherwise specified, the “alkylene group” includes linear, branched and cyclic divalent saturated hydrocarbon groups.
The “halogenated alkyl group” is a group in which part or all of the hydrogen atoms of the alkyl group are substituted with a halogen atom, and examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
“Aliphatic” is a relative concept with respect to aromatics, and is defined to mean groups, compounds, and the like that do not have aromaticity.

  ADVANTAGE OF THE INVENTION According to this invention, the pattern formation method useful for formation of a fine pattern can be provided.

It is a schematic process drawing explaining the 1st embodiment of the pattern formation method of this invention. It is a schematic process drawing explaining the 2nd embodiment of the resist pattern formation method of this invention.

≪Pattern formation method≫
The pattern forming method of the present invention includes a step (i) of forming a resist pattern on a support using a resist composition;
(Ii) forming a pattern reversal film by applying a reversal pattern forming material on the support on which the resist pattern is formed;
Removing the resist pattern by etching to form a reverse pattern (iii).
In the present invention, in particular, in the step (ii), the pattern reversal film is formed with a film thickness thicker than the height of the resist pattern, and then the resist pattern is removed by etching in the step (iii). Further, it is preferable that the upper portion of the pattern reversal film is removed to expose the resist pattern. As a result, the pattern reversal film is equivalent to the height of the resist pattern, and thus the etching selectivity can be obtained. However, the present invention is not limited to this, and the pattern reversal film may be formed with a film thickness thinner than the height of the resist pattern. In this case, it is not necessary to remove the upper portion of the pattern reversal film and expose the resist pattern, and the number of steps can be reduced.
In the present invention, the etching in the step (iii) is preferably dry etching from the viewpoint of simplicity such as etching selectivity control.
Hereinafter, embodiments of a resist pattern forming method of the present invention will be described with reference to the drawings. However, the present invention is not limited to this.

<First Embodiment>
In the first embodiment of the present invention, first, a support in which a lower layer film 2 is laminated on a substrate 1 is prepared, and on the lower layer film 2, as shown in FIG. A plurality of resist patterns 3 are formed (resist pattern forming step).
Next, as shown in FIG. 1B, a pattern reversal coating 4 is formed on the lower layer film 2 by applying the reversal pattern forming material of the present invention and filling the gaps between the plurality of resist patterns 3. Form (pattern reversal film forming step). In this embodiment, the pattern reversal coating 4 is formed with a film thickness thicker than the height of the resist pattern 3, and the upper surface of the resist pattern 3 is also covered with the reversal pattern reversal coating 4.
Next, as shown in FIG. 1C, the upper portion of the pattern reversal coating 4 is removed to expose the resist pattern 3 (resist pattern exposure step).
Next, as shown in FIG. 1D, the resist pattern 3 is etched from above the pattern reversal coating 4 to remove the resist pattern 3 (first etching step). As a result, a pattern (reversal pattern) 4 a in which the image of the resist pattern 3 is reversed is formed on the pattern reversal coating 4. For example, when the resist pattern 3 is a line pattern, a space pattern having the same width as the line pattern is formed as the reversal pattern 4a. When the resist pattern 3 is a dot pattern, the reversal pattern 4a is the same as the dot pattern. A hole pattern with a diameter is formed.
Subsequently, as shown in FIG. 1E, the lower layer film 2 is etched from above the pattern reversal coating 4 (second etching step). At this time, the pattern reversal film 4 on which the reversal pattern 4a is formed functions as an etching mask, and the lower layer film 2 below the reversal pattern 4a is removed. As a result, the reverse pattern 4 a is transferred to the lower layer film 2.
Hereinafter, each process will be described in more detail.

(Resist pattern formation process)
The substrate 1 is not particularly limited, and a conventionally known substrate can be used. For example, a substrate for an electronic component or a substrate on which a predetermined wiring pattern is formed can be exemplified. More specifically, a silicon substrate, a metal substrate such as copper, chromium, iron, and aluminum, a glass substrate, and the like can be given. As a material for the wiring pattern, for example, copper, aluminum, nickel, gold or the like can be used.

The lower layer film 2 is not particularly limited, and a known layer can be used as a layer provided under the resist film. The lower layer film 2 may be an inorganic film or an organic film. May be. An inorganic antireflection film (inorganic BARC) is an example of the inorganic film. Examples of the organic film include an organic antireflection film (organic BARC) and a lower layer film in a multilayer resist method.
Here, the multilayer resist method is a method in which at least one organic film and at least one resist film are provided on a substrate, and a lower layer patterning is performed using a resist pattern formed on the upper resist film as a mask. It is said that a pattern with a high aspect ratio can be formed. The multilayer resist method basically includes a method of forming a two-layer structure of an upper resist film and a lower organic film, and one or more intermediate layers (metal thin film, etc.) between the resist film and the organic film. ) And a method of forming a multilayer structure of three or more layers. According to the multilayer resist method, the required thickness is ensured by the lower organic film, so that the resist film can be thinned and a fine pattern with a high aspect ratio can be formed.
The inorganic film can be formed, for example, by applying an inorganic antireflective film composition such as a silicon-based material on a substrate and baking it.
The organic film is formed by, for example, applying an organic film forming material in which a resin component or the like constituting the film is dissolved in an organic solvent to a substrate with a spinner or the like, preferably 200 to 300 ° C., preferably 30 to 300 seconds, More preferably, it can be formed by baking under heating conditions of 60 to 180 seconds.
The organic film forming material for forming the organic film is not particularly limited, and a resist or resin generally used in manufacturing a semiconductor element or a liquid crystal display element can be used. However, the organic film forming material does not necessarily require sensitivity to an electron beam or light like a resist film.
The organic film forming material forms an organic film that can be etched, especially dry-etched, so that the reverse pattern can be transferred to the organic film by etching the organic film using the pattern reversal film on which the reverse pattern is formed. A material that can be used is preferable. Among these, a material capable of forming an organic film capable of etching such as oxygen plasma etching is preferable.
The lower layer film 2 is preferably an organic film because it has an excellent etching selectivity with the pattern reversal coating 4. In addition, it is preferable that an organic film is provided as the lower layer film 2 because it is easy to form a pattern with a high aspect ratio on the substrate as described above, and is useful in manufacturing semiconductors.

  In this embodiment, a laminated body in which the lower layer film 2 is laminated on the substrate 1 is used as the support. However, the present invention is not limited to this, and the substrate 1 is used as the support. The resist pattern 3 may be directly formed thereon.

The resist composition used for forming the resist pattern 3 is not particularly limited, and a resist composition proposed so far can be used.
As the resist composition, a chemically amplified resist composition is preferably used because it is particularly excellent in sensitivity, resolution, and the like. However, the present invention is not limited to this, and a non-chemically amplified resist composition may be used. The composition of the resist composition will be described later in detail.

As a method of forming the resist pattern 3 using the resist composition, a conventionally known method can be used. For example, a resist pattern is formed by a method including a step of forming a resist film on a support using the resist composition, a step of exposing the resist film, and a step of developing the resist film to form a resist pattern. it can.
What is necessary is just to set suitably the specific conditions at the time of this resist pattern formation according to the kind of resist composition to be used. As a specific example, when a chemically amplified resist composition is used, for example, the resist pattern forming method can be performed as follows. That is, first, the resist composition is coated on the support 1 with a spinner or the like, and pre-baked (post-apply bake (PAB)) for 40 to 120 seconds, preferably 60 to 90 seconds under a temperature condition of 80 to 150 ° C. To form a resist film, for example, using an exposure apparatus such as an ArF exposure apparatus, an electron beam drawing apparatus, an EUV exposure apparatus, or the like, through a photomask (mask pattern) on which a predetermined pattern is formed, or After selective exposure by drawing or the like by direct irradiation with an electron beam without passing through a mask pattern, PEB (post-exposure heating) is applied for 40 to 120 seconds, preferably 60 to 90 seconds, at a temperature of 80 to 150 ° C. Subsequently, this is developed using an alkali developer, for example, an aqueous solution of 0.1 to 10% by mass of tetramethylammonium hydroxide (TMAH), preferably rinsed with pure water and dried. In some cases, a baking process (post-bake) may be performed after the development process. In this way, the resist pattern 2 can be obtained.

The film thickness of the resist film is not particularly limited, and can be appropriately selected in consideration of the target dimension of the resist pattern to be formed.
The film thickness is preferably 150 nm or less, more preferably 120 nm or less, and even more preferably 100 nm or less because a fine resist pattern (for example, a resist pattern having a dimension of 100 nm or less) can be easily formed and the effectiveness of the present invention is high.
Although the minimum of this film thickness is not specifically limited, Preferably it is 50 nm or more. When the film thickness is 50 nm or more, the pattern reversal coating 4 can be formed with a film thickness sufficient to function as an etching mask when the resist pattern 3 and the lower layer film 2 are etched.

The wavelength used for the exposure is not particularly limited, and ArF excimer laser, KrF excimer laser, F ₂ excimer laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), EB (electron beam), X-ray, soft X-ray, etc. Can be done using radiation. When using a chemically amplified resist composition, among these, KrF excimer laser, ArF excimer laser, EB or EUV is preferably used.

The exposure may be performed by normal exposure (dry exposure) performed in an inert gas such as air or nitrogen, or may be performed by immersion exposure.
In immersion exposure, a solvent (immersion medium) having a refractive index larger than the refractive index of air is applied to a portion between a lens and a resist film on a wafer, which is conventionally filled with an inert gas such as air or nitrogen. This is a method of performing exposure in a state where More specifically, the immersion exposure is a solvent (immersion medium) having a refractive index larger than the refractive index of air between the resist film obtained as described above and the lowermost lens of the exposure apparatus. And in that state, exposure can be performed through a desired photomask (immersion exposure).
As the immersion medium, a solvent having a refractive index larger than the refractive index of air and smaller than the refractive index of the resist film exposed by the immersion exposure is preferable. The refractive index of such a solvent is not particularly limited as long as it is within the above range.
Examples of the solvent having a refractive index larger than the refractive index of air and smaller than the refractive index of the resist film include water, a fluorine-based inert liquid, a silicon-based solvent, and a hydrocarbon-based solvent.
Specific examples of the fluorinated inert liquid include fluorinated compounds such as C ₃ HCl ₂ F ₅ , C ₄ F ₉ OCH ₃ , C ₄ F ₉ OC ₂ H ₅ , and C ₅ H ₃ F ₇ as main components. Examples thereof include liquids, and those having a boiling point of 70 to 180 ° C are preferable, and those having a boiling point of 80 to 160 ° C are more preferable. It is preferable that the fluorine-based inert liquid has a boiling point in the above range since the medium used for immersion can be removed by a simple method after the exposure is completed.
As the fluorine-based inert liquid, a perfluoroalkyl compound in which all hydrogen atoms of the alkyl group are substituted with fluorine atoms is particularly preferable. Specific examples of the perfluoroalkyl compound include a perfluoroalkyl ether compound and a perfluoroalkylamine compound. More specifically, examples of the perfluoroalkyl ether compound include perfluoro (2-butyl-tetrahydrofuran) (boiling point 102 ° C.), and examples of the perfluoroalkylamine compound include perfluorotributylamine (boiling point). 174 ° C.).

In the present invention, the resist pattern 3 may be formed by a double patterning process. The double patterning process is a method of forming a resist pattern by performing patterning twice or more (for example, “Proceedings of SPIE, 5256, 985-994 (2003).”). , "Proceedings of SPIE, 6153, 615301-1-19 (2006)."). According to the double patterning process, even if a light source having the same exposure wavelength is used as compared with single patterning in which a series of steps (lithography steps) from formation of the resist film to development are performed once to form a resist pattern, Even when the same resist composition is used, it is possible to form a resist pattern with higher resolution at a higher density. The double patterning process can be performed using an existing exposure apparatus.
There are several types of double patterning processes. For example, (1) a method of forming a pattern by repeating a lithography process (from application of a resist composition to exposure and development) and an etching process at least twice, and (2) a lithography process And (3) a method of forming a resist film after forming a resist film, performing selective exposure to the resist film twice or more, and developing to form a resist pattern (multiple exposure method). Among these, (2) or (3) is preferable, and (2) is particularly preferable.
The method for forming a resist pattern by the double patterning process (2) will be described in detail in a second embodiment described later.

(Pattern forming process for pattern reversal)
In this step, a pattern reversal film 4 is formed by applying a reversal pattern forming material on the lower layer film 2 on which the resist pattern 3 is formed in the step (i), and filling gaps between the plurality of resist patterns 3. Form.
As the reverse pattern forming material, a material containing a titanium-containing polymer (T) formed by dehydration condensation of a hydrolyzate of tetraalkoxy titanium is used. The reverse pattern forming material will be described later in detail.
The method for applying the reverse pattern forming material onto the lower layer film 2 is not particularly limited, and known means such as a spinner, a coater, a dispenser and the like can be used.
The application may be performed so that a film for pattern reversal having a desired film thickness can be formed.
The application is performed so that at least the resist pattern 3 in the region where the reversal pattern 4 a is to be formed is covered with the pattern reversal coating 4. At this time, the pattern reversal coating 4 may be performed so that the entire lower film 2 is covered, or a part of the lower film 2 may be covered. For example, application to a region where the resist pattern 3 is not formed may be omitted.
The difference between the film thickness of the pattern reversal coating 4 and the height of the resist pattern 3 is preferably 1 to 20 nm and more preferably 1 to 10 nm in consideration of the subsequent resist pattern exposure step.
After coating, baking is preferably performed for the purpose of drying the coating film (volatilization of the organic solvent) and the like. 80-250 degreeC is preferable and, as for the baking temperature in a baking process, 80-200 degreeC is more preferable. The baking time is not particularly limited, and may be set as appropriate in consideration of the baking temperature and the like.

It is preferable that the pattern reversal coating 4 has a certain thickness so that sufficient etching resistance can be obtained when the resist pattern is etched in the (first etching step). From this viewpoint, the film thickness of the pattern reversal coating 4 is preferably 5 nm or more, and more preferably 10 nm or more.
Further, considering the ease of exposing the resist pattern in the subsequent resist pattern exposure step, the upper limit of the film thickness of the pattern reversal coating 4 is preferably the height of the resist pattern 3 +20 nm. It is more preferable that the height is 3 + 10 nm.
Preferably, the film thickness of the pattern reversal coating 4 is in the range of 5 nm to the height of the resist pattern 3 +20 nm, and particularly preferably in the range of 10 nm to the height of the resist pattern 3 +10 nm.

(Resist pattern exposure process)
In the resist pattern exposing step, the upper portion of the pattern reversal film 4 is removed and the upper surface of the resist pattern 3 is exposed.
The method for removing the upper portion of the pattern reversal coating 4 is not particularly limited, and may be performed by, for example, etching (etchback), or a known smoothing method may be used. Examples of the smoothing method include chemical mechanical polishing (CMP).

In the resist pattern exposure step, the upper portion of the pattern reversal film 4 is preferably removed by etch back.
A known etching method can be used as the etching back method.
In the present invention, the etch-back of the pattern reversal coating 4 is preferably performed by dry etching from the viewpoint of simplicity of the processing step.
Known dry etching methods include chemical etching such as downflow etching and chemical dry etching; physical etching such as sputter etching and ion beam etching; and chemical and physical etching such as RIE (reactive ion etching). This method can be used.
The most common dry etching is parallel plate RIE. In this method, first, a multilayer laminate is put into a chamber of an RIE apparatus, and a necessary etching gas is introduced. When a high frequency voltage is applied to the holder of the multilayer stack placed in parallel with the upper electrode in the chamber, the etching gas is turned into plasma. In plasma, there are charged particles such as positive and negative ions and electrons, and etching species such as neutral active species. When these etching species are adsorbed on the lower resist layer, a chemical reaction occurs, the reaction product is detached from the surface and exhausted to the outside, and etching proceeds.
As an etching gas used for etch back, a halogen-based gas is preferable. Examples of the halogen-based gas include hydrocarbon gases in which some or all of the hydrogen atoms are substituted with halogen atoms such as fluorine atoms and chlorine atoms, and specifically, fluorocarbon gases and carbon chloride gases. Etc. Examples of the fluorocarbon gas include a CF gas such as tetrafluoromethane (CF ₄ ) gas, a CHF gas such as trifluoromethane (CHF ₃ ) gas, and the like. Examples of the carbon chloride-based gas include tetrachloromethane (CCl ₄ ) gas. Any one of these etching gases may be used alone, or two or more thereof may be mixed and used. Further, a nitrogen gas, a rare gas (such as argon gas), or the like may be mixed with the etching gas.
As an etching gas used for the etch back, a fluorocarbon gas is preferable, and CF ₄ gas and / or CHF ₃ gas is particularly preferable.

(First etching process)
In the first etching step, etching is performed until the material of the resist pattern 3 is removed and the surface of the lower layer film 2 is exposed under the condition that the pattern reversal coating 4 is difficult to remove. As a result, the resist pattern 3 is removed, and as a result, a reversal pattern 4a is formed in the pattern reversal film 4 as shown in FIG.
The resist pattern 3 can be etched by a known etching method.
In the present invention, the resist pattern 3 is preferably etched by dry etching. As a dry etching method, a known method similar to the above can be used.
The type of etching gas used at this time is not particularly limited as long as the etching selectivity can be obtained between the pattern reversal film 4 serving as an etching mask and the resist pattern 3, for example, oxygen (O ₂ ) gas or sulfur dioxide gas. And the halogen-based gas mentioned above. Any one of these etching gases may be used alone, or two or more thereof may be mixed and used. Further, a nitrogen gas, a rare gas (such as argon gas), or the like may be mixed with the etching gas.
As an etching method in the first etching step, oxygen plasma etching (dry etching using plasma obtained from O ₂ gas) is particularly preferable because of high etching selectivity with the pattern reversal coating 4.

(Second etching process)
In the second etching step, etching is performed until the surface of the substrate 1 is exposed under the condition that the material constituting the lower layer film 2 is removed and the pattern reversal coating 4 is difficult to remove. Thereby, the pattern reversal film 4 (upper layer pattern 4A) on which the reversal pattern 4a is formed serves as an etching mask, and the lower layer film 2 below the reversal pattern 4a is removed. As a result, as shown in FIG. The inversion pattern 4a is transferred to the lower layer film 2.
The resist pattern 3 can be etched by a known etching method.
In the present invention, the lower layer film 2 is preferably etched by dry etching. As a dry etching method, a known method similar to the above can be used.
The type of etching gas used at this time may be any as long as the etching selectivity can be obtained between the pattern reversal coating 4 serving as an etching mask and the lower layer film 2, and can be appropriately set in consideration of each material. Good. For example, when the lower layer film 2 is an organic film such as an organic antireflection film, the same film as the first etching process can be used, and in particular, the etching selectivity with the pattern reversal film 4 is high. Therefore, oxygen plasma etching is preferable.
The second etching step may be performed continuously following the first etching step. For example, when the lower layer film 2 is an organic film such as an organic antireflection film, the etching can be continuously performed under the same conditions as in the first etching step.
After the etching, a step of removing the residue or cleaning the substrate can be performed as necessary.

A pattern in which the pattern reversal film 4 (upper layer pattern 4A) on which the reversal pattern 4a is formed and the lower layer film 2 (lower layer pattern 2A) having a pattern to which the reversal pattern 4a is transferred are laminated as described above. (Laminated pattern) is formed on the substrate 1.
The laminated pattern can be used for various purposes. For example, it can be used as it is as a structure (for example, a circuit) on the substrate 1 or as a mask for transferring the same pattern as the laminated pattern to the substrate 1.
Moreover, it is good also as only a lower layer pattern by removing an upper layer pattern among this laminated pattern. The lower layer pattern can be used for various purposes in the same manner as the laminated pattern. For example, a semiconductor device or the like can be manufactured by etching the substrate 1 using the lower layer pattern as a mask.

As shown in the first embodiment, since the space pattern or the hole pattern can be obtained as an inverted pattern, the resist pattern 3 is preferably a line pattern and / or a dot pattern.
Such a reverse pattern has a resolution, a shape, and a lithography margin (for example, a margin with respect to the exposure amount and the depth of focus (EL) compared to the case where an isolated space pattern (trench pattern), a space and line pattern, a hole pattern, or the like is directly formed. The pattern forming ability of the margin and the DOF margin) and the perpendicularity of the pattern shape is excellent. In other words, since these patterns need to remove a very small part of the resist film and a fine region, as described above, pattern formation under weak light incident intensity is forced and the pattern forming ability is greatly limited. However, since the pattern forming ability when forming the reverse pattern depends on the pattern forming ability when forming a resist pattern (isolated line pattern, line and space pattern, dot pattern, etc.), the trench pattern and space and line Compared to the case where the pattern and hole pattern are directly formed, the pattern forming ability is less limited, and a good resist pattern can be formed.

<Second Embodiment>
Next, a second embodiment of the present invention will be described.
The present embodiment is performed in the same procedure as the first embodiment except that in the (resist pattern forming step) in the first embodiment, a resist pattern of a hole pattern is formed as a resist pattern 3 by a double patterning process. it can.
The formation of the resist pattern by the double patterning process is preferably performed by the method (2).
The resist pattern can be formed by, for example, applying a first resist composition on a support to form a first resist film, selectively exposing the first resist film, and performing alkali development. Forming a first resist pattern;
On the support on which the first resist pattern is formed, a second resist composition is applied to form a second resist film, the second resist film is selectively exposed, and alkali development is performed. And forming a second resist pattern;
It can implement by the method of including.
According to this method, a resist pattern composed of the first resist pattern and the second resist pattern is formed on the support.

Hereinafter, this embodiment will be described in more detail with reference to FIG.
In the present embodiment, first, the first patterning step is performed as shown in FIGS.
In the first patterning step, first, as shown in FIG. 2A, a first resist composition 11 is formed by applying a first resist composition on a substrate 1 on which a lower layer film 2 is laminated. Then, the first resist film 11 is exposed through a photomask 21 on which a predetermined pattern is formed.
At this time, in the case of the positive type, the solubility of the exposed portion in the alkaline developer increases, and in the case of the negative type, the solubility of the exposed portion in the alkaline developer decreases.
Therefore, by developing the first resist film 11 with an alkali developer, a plurality of dot patterns 11a are formed on the lower layer film 2 as shown in FIG.

Next, a second patterning step is performed as shown in FIGS.
In the second patterning step, first, as shown in FIG. 2C, a second resist composition is applied on the lower layer film 2 on which the dot pattern 11a is formed, and the second pattern composition covers the dot pattern 11a. The resist film 12 is formed, and the second resist film 12 is exposed through a photomask 22 on which a predetermined pattern is formed.
At this time, in the case of the positive type, the solubility of the exposed portion in the alkaline developer increases, and in the case of the negative type, the solubility of the exposed portion in the alkaline developer decreases.
Therefore, when the second resist film 12 is developed with an alkaline developer, a dot pattern 11a derived from the first resist film 11 is formed on the lower layer film 2 as shown in FIG. As a result, the dot pattern 12a derived from the second resist film 12 remains.
The resist pattern (resist pattern composed of the dot pattern 11a and the dot pattern 12a) formed on the lower layer film 2 in this way is narrower than the resist pattern (only the dot pattern 11a) formed in one patterning step. The dense thing.

The subsequent steps can be carried out in the same manner as the (pattern inversion film forming step), (first etching step) and (second etching step) of the first embodiment.
That is, the reverse pattern forming material of the present invention is applied on the lower layer film 2 on which the dot pattern 11a and the dot pattern 12a are formed, and as shown in FIG. A pattern reversal coating 4 filling the gap is formed.
Next, as shown in FIG. 2F, the upper portion of the pattern reversal coating 4 is removed by etch back using CF ₄ gas or the like to expose the dot pattern 11a and the dot pattern 12a.
Next, as shown in FIG. 2G, etching (etching with O ₂ gas or the like) is performed on the dot pattern 11a and the dot pattern 12a from above the pattern reversal coating 4. Thereby, the dot pattern 11a and the dot pattern 12a are removed, and a reverse pattern is formed. Subsequently, the reverse pattern is transferred to the lower layer film 2 by performing etching on the lower layer film 2.
As a result, a hole pattern having the same dimensions as the initial resist pattern (dot pattern 11a and dot pattern 12a) is formed on the substrate 1 with a higher aspect ratio.

Specifically, the first patterning step and the second patterning step can be performed in the same manner as in the (resist pattern forming step) of the first embodiment, respectively.
Each of the first resist composition and the second resist composition used in each step may be a positive type or a negative type.
In the second patterning step, the thickness of the second resist film 12 is preferably at least the same as or higher than the height of the dot pattern 11a. That is, when the substrate 1 is viewed from the second resist film 12 side, the surface is preferably flat.
The selective exposure of the second resist film 4 is performed so that the dot pattern 12a is formed at a position different from the position where the dot pattern 11a is formed.
Such selective exposure can be performed, for example, by using a photomask different from the photomask 21 as the photomask 22. Further, when using positive types as the first resist composition and the second resist composition, or using negative types, respectively, for example, the position of the photomask 21 used in the first patterning step. This can also be implemented by slightly deviating and using this as the photomask 22.

Thus, in the second patterning step, by performing selective exposure so that the position of the second resist pattern and the position of the first resist pattern do not overlap at all, the pattern is more effective than the first resist pattern. A narrow pitch resist pattern having a narrow interval (pitch) is obtained.
For example, in the case of forming a line and space resist pattern instead of the dot pattern as shown in FIG. 2, in the first patterning step, a line and space pattern in which a plurality of lines are arranged at a constant pitch is used. After forming a line-and-space resist pattern using a photomask, in the second patterning step, a line pattern is formed at an intermediate position between the line pattern and the line pattern formed in the first patterning step. A line and space resist pattern (dense pattern) arranged in a line with a narrower pitch than the line and space resist pattern (sparse pattern) formed in (1) is formed. The “sparse pattern” is preferably a line and space pattern having a line width: space width = 1: 2 or larger in the line and space resist pattern.
However, the present invention is not limited to this, and the position of the second resist pattern formed in the second patterning step and the position of the first resist pattern formed in the first patterning step partially overlap. Also good.
In the second patterning step, the photomask 21 is used by rotating and moving as the photomask 22, or a photomask having a pattern different from that of the photomask 21 (for example, a line and space pattern in the first patterning step). Various resist patterns can be formed by using a photomask, a mask pattern of holes in the second patterning step, or the like.

In this embodiment, the selective exposure is performed by exposure through the photomasks 21 and 22, but the present invention is not limited to this, and exposure without passing through the photomasks 21 and 22, for example, drawing by EB or the like. May be performed.
Further, after the second patterning step, the same patterning step as the second patterning step may be repeated a plurality of times. That is, on the lower layer film 2 on which the resist pattern is formed in the second patterning step, a resist composition is applied to form a resist film, the resist film is selectively exposed and developed to form a resist pattern. The forming operation may be performed a plurality of times. Thereby, a denser pattern with a narrower pitch or a pattern with a complicated shape can be formed.

<Inverted pattern forming material>
The material for forming a reverse pattern used in the present invention contains a titanium-containing polymer (T) (hereinafter referred to as (T) component) formed by dehydration condensation of a hydrolyzate of tetraalkoxy titanium. Such a material has a good embedding property to a fine resist pattern, and the formed pattern reversal film has a high etching selectivity with respect to the resist film (resist pattern). Therefore, by using the reverse pattern forming material, it is possible to form a pattern having an excellent shape such as a high cross-sectional rectangularity.

As the component (T), a polymer produced by mixing and reacting tetraalkoxytitanium, an organic solvent containing an alcoholic organic solvent, and an acid is preferably used.
In the reaction, first, an alcohol-based organic solvent and an acid react to produce water. The acid also acts as a catalyst, and tetraalkoxytitanium is hydrolyzed. At this time, Ti—O—R (R is an alkyl group) in tetraalkoxytitanium is decomposed to become Ti—OH. At the same time, Ti—OH reacts to cause an intermolecular dehydration condensation reaction to form a Ti—O—Ti bond. Thus, the target polymer is obtained by the hydrolysis reaction and the accompanying dehydration condensation reaction proceeding.
The polymer thus obtained is suitable for the present invention in terms of the etching rate. However, this invention is not limited to this, You may use a well-known thing as (T) component.

Examples of the tetraalkoxy titanium include those represented by the following general formula (t-1).
Ti (OR ¹ ) (OR ² ) (OR ³ ) (OR ⁴ ) (t−1)
[Wherein, R ^{1 to} R ⁴ are each independently an alkyl group which may have a substituent. ]

In the formula, the alkyl group in R ^{1 to} R ⁴ may be linear, branched or cyclic, and is preferably linear or branched, and preferably branched. Particularly preferred. 1-10 are preferable and, as for carbon number of this alkyl group, 1-5 are more preferable. However, the carbon number does not include the carbon number in the substituent. Specifically, methyl group, ethyl group, propyl group (n-propyl group, isopropyl group), butyl group (n-butyl group, isobutyl group, sec-butyl group, tert-butyl group), pentyl group (n- Pentyl group, isopentyl group, neopentyl group, etc.). Among these, an isopropyl group and a tert-butyl group are preferable.
The alkyl group may have a substituent. Here, “the alkyl group has a substituent” means that part or all of the hydrogen atoms bonded to the ring of the alkyl group are substituted with the substituent.
Specific examples of the substituent that the alkyl group may have include an alkoxy group.
The alkoxy group as the substituent is preferably an alkoxy group having 1 to 5 carbon atoms, preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group or a tert-butoxy group. Most preferred is an ethoxy group.
In formula (t-1), R ^{1 to} R ⁴ may be the same or different.

  Specific examples of tetraalkoxy titanium include tetramethoxy titanium, tetraethoxy titanium, tetrapropoxy titanium, tetrabutoxy titanium, tetrapentoxy titanium, tetrahexoxy titanium, tetranonoxy titanium, trimethoxyethoxy titanium, triethoxybutoxy titanium. , Dimethoxydiethoxytitanium, dimethoxydipropoxytitanium, diethoxydipropoxytitanium, diethoxydibutoxytitanium tetrakis (methoxypropoxy) titanium and the like. Any one of these tetraalkoxy titaniums may be used alone, or two or more thereof may be mixed and used.

The “alcohol-based organic solvent” is a compound in which at least one hydrogen atom of an aliphatic hydrocarbon is substituted with a hydroxyl group, and is a compound that is liquid at normal temperature and normal pressure.
The alcohol-based organic solvent used for the hydrolysis reaction is not particularly limited, and known alcohol-based organic solvents can be used. For example, it may be a monohydric alcohol or a polyhydric alcohol, which is a polyhydric alcohol derivative in which a part of the hydrogen atoms of the hydroxyl group of the polyhydric alcohol is substituted with a substituent such as an alkyl group or an acetyl group. May be. Specifically, monohydric alcohols such as methanol, ethanol, propanol and butanol; polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, glycerin, trimethylolpropane and hexanetriol; monoethers of the polyhydric alcohol (for example, Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether ,propylene Recall monopropyl ether, propylene glycol monobutyl ether, etc.) or mono acetates; and the like. Among these, a lower alcohol having 1 to 5 carbon atoms is preferable, and a monohydric alcohol is particularly preferable. Of these, ethanol is preferred. Any one of these organic solvents may be used alone, or two or more thereof may be used in combination.

As the organic solvent, the above-mentioned alcohol-based organic solvent may be used alone, or may be used by mixing with other organic solvents.
The other organic solvent is not particularly limited as long as it can dissolve tetraalkoxytitanium and its reaction product, and can be appropriately selected from, for example, known organic solvents. Specifically, esters such as methyl acetate, ethyl acetate, and butyl acetate; ketones such as acetone, methyl ethyl ketone, and methyl isoamyl ketone; ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, ethylene glycol dibutyl ether, And polyhydric alcohol ethers obtained by alkylating polyhydric alcohol ethers such as propylene glycol dimethyl ether, propylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, and diethylene glycol methyl ethyl ether.

Any acid can be used as long as it can generate water by reacting with the alcohol-based organic solvent. Either an organic acid or an inorganic acid can be used.
Examples of the inorganic acid include sulfuric acid, phosphoric acid, nitric acid, hydrochloric acid and the like. Of these, phosphoric acid and nitric acid are preferable.
Examples of organic acids include formic acid, oxalic acid, fumaric acid, maleic acid, acetic acid, acetic anhydride, propionic acid, n-butyric acid and the like; organic acids having sulfur-containing acid residues; esterified products thereof; It is done.
Examples of the organic acid having a sulfur-containing acid residue include organic sulfonic acids. Examples of the organic sulfonic acid include a general formula: R ⁵ —SO ₃ H [wherein R ⁵ is a hydrocarbon group which may have a substituent. ] Is represented. Examples of the hydrocarbon group in include an alkyl group and an aryl group. Examples of the substituent that the hydrocarbon group may have include a halogen atom such as a fluorine atom, a sulfonic acid group, a carboxy group, a hydroxyl group, an amino group, and a cyano group. Specific examples of the organic sulfonic acid include, for example, nonafluorobutanesulfonic acid, methanesulfonic acid, trifluoromethanesulfonic acid, dodecylbenzenesulfonic acid and the like from the viewpoint of the shape improvement effect under the resist pattern. Can be mentioned.
Examples of the esterified organic acid having a sulfur-containing acid residue include organic sulfates and organic sulfites.
As described above, the acid functions as a water generation source together with the alcohol solvent in the above reaction, and also functions as a catalyst (acid catalyst) for hydrolysis reaction and dehydration condensation reaction. From this viewpoint, the amount of acid used in the above reaction is preferably such that the concentration in the reaction system (ratio of the mass of the acid to the total mass of the reaction system) is 1-1000 ppm, and the amount is 5-800 ppm. More preferred.

The above reaction (hydrolysis / dehydration condensation) proceeds only by mixing, for example, tetraalkoxytitanium, an alcohol-based organic solvent, and an acid.
The reaction can be stopped by adding a chelating agent to the reaction system.
An aging step may be provided in order to grow the polymer at an appropriate polymerization rate before the addition of the chelating agent.

The reaction conditions in the above reaction may be appropriately determined in consideration of production efficiency, characteristics of the polymer to be obtained (for example, hydrolysis rate, chelate rate, etc.), reaction temperature, and the like.
For example, considering the production efficiency, the reaction temperature is preferably 15 to 30 ° C.
Moreover, the usage-amount of an alcohol type organic solvent and an acid is set in consideration of the hydrolysis rate of (T) component.
Here, the “hydrolysis rate” is the ratio of the “number of water molecules (number of moles)” to the “total number of alkoxy groups (number of moles)” present in the reaction system when hydrolyzing tetraalkoxytitanium ( Unit:%). The total number (number of moles) of the alkoxy group is determined as the number of moles of tetraalkoxytitanium used × 4.
The hydrolysis rate of the component (T) is preferably 25 to 200%, more preferably 50 to 150%, and further preferably 75 to 125%. By setting it within the above range, the masking property of the obtained film for pattern reversal becomes good.
The hydrolysis rate corresponds to the amount of water present in the reaction system at the time of reaction. When the amount of water is small, the hydrolysis rate is low, and when the amount of water is large, the hydrolysis rate is high. For example, when the amount of water in the reaction system is 1 to 8 mol times the molar amount of tetraalkoxytitanium, the hydrolysis rate of the TiO polymer is 25 to 200% (for example, 1 mol of tetraalkoxytitanium in the reaction system). If 4 moles of water are present, the hydrolysis rate is 100%.)
As described above, in the above reaction, water generated in the reaction between the alcoholic organic solvent and the acid is used for the hydrolysis reaction. Therefore, the reaction system can be adjusted by adjusting the amount of the alcoholic organic solvent and the acid used. The amount of water inside can be adjusted. For example, when 1 mol of ethanol and 1 mol of acetic acid are used, they react to produce 1 mol of water, so that either or both of the amounts used correspond to the desired amount of water. By setting the number, the amount of water in the reaction system can be set to a desired number of moles.
What is necessary is just to determine reaction time (time until a chelating agent is added after reaction start) suitably.

The chelating agent is not particularly limited, and a known chelating agent can be used. Specific examples include β-diketone compounds and glycol compounds.
Examples of β-diketone compounds include acetylacetone, trifluoroacetylacetone, hexafluoroacetylacetone, benzoylacetone, benzoyltrifluoroacetone, dibenzoylmethane, acetoacetate methyl ester, acetoacetate ethyl ester, acetoacetate butyl ester, etc. It is done.
Examples of the glycol compound include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, trimethylene glycol, butanediol, hexylene glycol and the like.
Any one of these may be used alone, or two or more thereof may be mixed and used.
The chelating agent is usually used so that the resulting (T) component has a chelate rate of 25 to 200%. Here, the “chelation rate” corresponds to the ratio (unit:%) of “total number of hydroxyl groups that can be capped with a chelating agent” to “total number of hydroxyl groups (number of moles)” that can exist in the reaction system. It is calculated from the amount charged.

After completion of the reaction, the resultant reaction solution contains the synthesized (T) component and the organic solvent used for the reaction. The reaction solution can be used as a reversal pattern forming material as it is. In consideration of the film thickness of the pattern reversal film to be formed, the coating method, and the like, dilution or concentration with an organic solvent may be performed. The organic solvent used for the dilution may be the same as the organic solvent used in the reaction, or another organic solvent may be used. Moreover, you may substitute a part or all of the used organic solvent by another organic solvent. For example, considering that the reverse pattern forming material is applied onto the resist pattern, the reverse pattern forming material preferably contains an organic solvent that does not dissolve the resist pattern as the organic solvent. The organic solvent will be described later in detail.
Concentration and solvent replacement can be carried out by known methods.

  The solid content concentration of the (T) component in the reverse pattern forming material is usually preferably about 1 to 20% by mass and more preferably about 3 to 10% by mass.

[Organic solvent]
In the pattern forming method of the present invention, the reverse pattern forming material is applied on a support on which a resist pattern is formed, and therefore needs to have fluidity (for example, liquid) suitable for application. From this point of view, the reversal pattern forming material preferably contains an organic solvent (hereinafter referred to as (S ′) component).
The component (S ′) may be any component that can dissolve the component contained in the reversal pattern forming material, and can be appropriately selected from known organic solvents.
Considering that the reverse pattern forming material is applied on the resist pattern, the component (S ′) is preferably an organic solvent that does not dissolve the resist pattern (hereinafter referred to as “S1 ′) component”. Thus, when the pattern reversal film is formed by applying the reversal pattern forming material on the support on which the resist pattern is formed, the resist pattern shape is kept good.
Here, whether or not the organic solvent to be used is “does not dissolve the resist pattern” can be determined by the following method.
A resist composition is applied on a support and dried to form a resist film having a thickness of 0.2 μm under a condition of 23 ° C., which is immersed in the organic solvent. At this time, even after 60 minutes from the start of immersion, the resist film disappears or the film thickness does not change significantly (preferably the film thickness of the resist film is not less than 0.16 μm). Is not dissolved ".

Specific examples of the component (S1 ′) include alcohol-based organic solvents, ether-based organic solvents having no hydroxyl group, and fluorine-based organic solvents.
As described above, the “alcohol-based organic solvent” is a compound in which at least one hydrogen atom of an aliphatic hydrocarbon is substituted with a hydroxyl group and is a liquid at normal temperature and normal pressure. The aliphatic hydrocarbon may be saturated or unsaturated, and is preferably saturated. Further, it may be any of linear, branched and cyclic, and is preferably linear or branched.
The alcohol organic solvent used as the component (S1 ′) is more preferably a monohydric alcohol. Among them, although depending on the number of carbons, a primary or secondary monohydric alcohol is preferable. Alcohol is most preferred. Here, the monohydric alcohol means a case where the number of hydroxy groups contained in the alcohol molecule is 1, and does not include a dihydric alcohol, a trihydric alcohol, or a derivative thereof.
The alcohol-based organic solvent has a functional group other than a hydroxyl group (for example, an ether bond (C—O—C), an ester bond (C—C (═O) —O—C), a carboxy group, etc.) in the structure. ) Is preferred.
The alcoholic organic solvent used as the component (S1 ′) preferably has a boiling point of 80 to 160 ° C., more preferably 90 to 150 ° C., and preferably 100 to 135 ° C. From the viewpoint of the stability of the heat treatment and the heating temperature of the PAB process or PEB process, it is most preferable. Specific examples of such alcohol-based organic solvents include n-pentyl alcohol (boiling point 138.0 ° C.), s-pentyl alcohol (boiling point 119.3 ° C.), t-pentyl alcohol (101.8 ° C.), isopentyl alcohol ( Boiling point 130.8 ° C), isobutanol (also called isobutyl alcohol or 2-methyl-1-propanol) (boiling point 107.9 ° C), isopropyl alcohol (boiling point 82.3 ° C), 2-ethylbutanol (boiling point 147 ° C) Neopentyl alcohol (boiling point 114 ° C), n-butanol (boiling point 117.7 ° C), s-butanol (boiling point 99.5 ° C), t-butanol (boiling point 82.5 ° C), 1-propanol (boiling point 97. 2 ° C), n-hexanol (boiling point 157.1 ° C), 2-heptanol (boiling point 160.4 ° C), 3-heptanol (Boiling point 156.2 ° C), 2-methyl-1-butanol (boiling point 128.0 ° C), 2-methyl-2-butanol (boiling point 112.0 ° C), 4-methyl-2-pentanol (boiling point 131. 8 ° C.). In particular, isobutanol (2-methyl-1-propanol), 4-methyl-2-pentanol, n-butanol, and the like are preferable because the effect of containing the component (S1 ′) is good. Among these, isobutanol and n-butanol are preferable, and isobutanol is most preferable.
However, this invention is not limited to this, You may use the alcoholic organic solvent whose boiling point is less than 80 degreeC as an alcoholic organic solvent. Examples of the alcohol organic solvent include methanol, ethanol and the like.
Any one of these alcohol-based organic solvents may be used alone, or two or more thereof may be used in combination.

The “ether-based organic solvent having no hydroxyl group” is a compound that has an ether bond (C—O—C) in its structure, has no hydroxyl group, and is liquid at normal temperature and pressure. The ether-based organic solvent having no hydroxyl group preferably further has no carbonyl group in addition to the hydroxyl group.
Preferred examples of the ether organic solvent having no hydroxyl group include compounds represented by the following general formula (s1′-1).
R ⁴⁰ —O—R ⁴¹ (s1′-1)
[Wherein, R ⁴⁰ and R ⁴¹ each independently represent a hydrocarbon group. Alternatively, R ⁴⁰ and R ⁴¹ may be bonded to form a ring. -O- represents an ether bond. ]

In the above formula, examples of the hydrocarbon group for R ⁴⁰ and R ⁴¹ include an alkyl group and an aryl group, and an alkyl group is preferred. Among ^them, it is preferable that any of R ^{40, R 41} is an alkyl ^group, more preferably a ^{R 40} and ^{R 41} are the same alkyl group.
As each of the alkyl groups of R ^40, R ^41, not particularly limited, for example, straight, branched or cyclic alkyl group, and the like. In the alkyl group, part or all of the hydrogen atoms may or may not be substituted with a halogen atom or the like.
The alkyl group preferably has 1 to 15 carbon atoms, and more preferably 1 to 10 carbon atoms because the coating properties of the negative resist composition are good. Specific examples include an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-pentyl group, an isopentyl group, a cyclopentyl group, and a hexyl group, and an n-butyl group and an isopentyl group are particularly preferable. .
The halogen atom that may be substituted for the hydrogen atom of the alkyl group is preferably a fluorine atom.
Each aryl group for R ⁴⁰ and R ⁴¹ is not particularly limited, and is, for example, an aryl group having 6 to 12 carbon atoms, in which part or all of the hydrogen atoms are alkyl groups, alkoxy groups, It may or may not be substituted with a halogen atom or the like.
The aryl group is preferably an aryl group having 6 to 10 carbon atoms because it can be synthesized at a low cost. Specifically, a phenyl group, a benzyl group, a naphthyl group, etc. are mentioned, for example.
The alkyl group that may be substituted for the hydrogen atom of the aryl group is preferably an alkyl group having 1 to 5 carbon atoms, and is a methyl group, ethyl group, propyl group, n-butyl group, or tert-butyl group. Is more preferable.
As the alkoxy group which may substitute the hydrogen atom of the said aryl group, a C1-C5 alkoxy group is preferable and a methoxy group and an ethoxy group are more preferable.
The halogen atom that may substitute the hydrogen atom of the aryl group is preferably a fluorine atom.
In the above formula, R ⁴⁰ and R ⁴¹ may combine to form a ring.
R ⁴⁰ and R ⁴¹ are each independently a linear or branched alkylene group (preferably an alkylene group having 1 to 10 carbon atoms), and the end of R ^{40 and} the end of R ⁴¹ are bonded to each other. To form a ring. In addition, the carbon atom of the alkylene group may be substituted with an oxygen atom.
Specific examples of such ether-based organic solvents include 1,8-cineol, tetrahydrofuran, dioxane and the like.

The boiling point (under normal pressure) of the ether-based organic solvent having no hydroxyl group is preferably 30 to 300 ° C, more preferably 100 to 200 ° C, and further preferably 140 to 180 ° C. By being equal to or higher than the lower limit of the temperature range, the component (S ′) is less likely to evaporate during spin coating during application of the negative resist composition, so that coating unevenness is suppressed and coating properties are improved. On the other hand, by being below the upper limit, the (S ′) component is sufficiently removed from the resist film by pre-baking, and the formability of the second resist film is improved. Moreover, when the temperature is within this range, the effect of reducing the film thickness of the resist pattern and the stability of the composition during storage are further improved. Moreover, it is preferable also from a viewpoint of the heating temperature of a PAB process or a PEB process.
Specific examples of ether organic solvents having no hydroxyl group include, for example, 1,8-cineol (boiling point 176 ° C.), dibutyl ether (boiling point 142 ° C.), diisopentyl ether (boiling point 171 ° C.), dioxane (boiling point 101 ° C.). ), Anisole (boiling point 155 ° C.), ethyl benzyl ether (boiling point 189 ° C.), diphenyl ether (boiling point 259 ° C.), dibenzyl ether (boiling point 297 ° C.), phenetole (boiling point 170 ° C.), butyl phenyl ether, tetrahydrofuran (boiling point 66 ° C.) ), Ethyl propyl ether (boiling point 63 ° C.), diisopropyl ether (boiling point 69 ° C.), dihexyl ether (boiling point 226 ° C.), dipropyl ether (boiling point 91 ° C.) and the like.
The ether-based organic solvent having no hydroxyl group is preferably a cyclic or chain-shaped ether-based organic solvent because it has a good effect of reducing the film loss of the resist pattern, and among them, 1,8-cineole, dibutyl ether. And at least one selected from the group consisting of diisopentyl ether is preferred.

The “fluorine-based organic solvent” is a compound containing a fluorine atom and is a liquid at normal temperature and normal pressure.
Examples of the fluorine-based solvent include perfluoro-2-butyltetrahydrofuran.

Any one of these (S1 ′) components may be used alone, or two or more thereof may be mixed and used.
The component (S1 ′) is at least one selected from the group consisting of an alcohol solvent and an ether organic solvent having no hydroxyl group, from the viewpoint of applicability and solubility of materials such as the component (T). Are preferred, and ether-based organic solvents having no hydroxyl group are more preferred.

When the component (S1 ′) is included as the component (S ′), the component (S ′) is an organic solvent other than the component (S1 ′) as long as the effects of the present invention are not impaired (hereinafter referred to as (S2 ′)). May be included). The component (S2) may be any component that can dissolve each component to be used, and examples thereof include the same components as those described as the component (S) in the resist composition described later.
However, in order to sufficiently obtain the effect of including the (S1 ′) component, the ratio of the (S1 ′) component in the (S ′) component is 50 to 100 with respect to the total mass of the (S ′) component. % By mass is preferable, 80 to 100% by mass is more preferable, and 100% by mass is most preferable. That is, the (S ′) component is most preferably composed of only the (S1 ′) component.

  The amount of the (S ′) component used in the reverse pattern forming material is not particularly limited, and may be set as appropriate so that the reverse pattern forming material becomes a liquid that can be applied onto the support.

[Other ingredients]
In addition to the above, the reversal pattern forming material may contain additives such as an antifoaming agent, a surfactant, and a stabilizer as necessary.
A conventionally well-known thing can be utilized as an antifoamer, for example, a silicone type compound, a fluorine-type compound, etc. are mentioned.
As the surfactant, conventionally known ones such as an anionic surfactant, a cationic surfactant, a nonionic surfactant, and an amphoteric surfactant can be used.

  The reversal pattern forming material can be prepared, for example, by mixing the above components with a stirrer and, if necessary, filtering with a filter such as a 5 μm membrane filter.

<Resist composition>
The resist composition used in the pattern forming method of the present invention is not particularly limited, and resist compositions that have been proposed so far can be used.
Resist compositions include a positive type in which alkali solubility increases upon exposure and a negative type in which alkali solubility decreases upon exposure. In the present invention, the resist composition may be a positive type or a negative type. A positive resist composition is preferably used.
The type of resist composition may be chemically amplified or non-chemically amplified, but it is excellent in sensitivity, resolution, etc., and can form a fine resist pattern. The product is preferably used.
There is no restriction | limiting in particular as a chemically amplified resist composition, It can select suitably from many chemically amplified resist compositions proposed until now and can use it. The chemically amplified resist composition includes a base material component (A) whose solubility in an alkaline developer is changed by the action of an acid (hereinafter referred to as the component (A)) and acid generation that generates an acid upon irradiation with radiation. What contains an agent component (B) (henceforth (B) component) is common.
Here, the “base component” of the resist composition refers to an organic compound having film forming ability. In general, a base material component (for example, a component (A) described later) is blended in the resist composition in order to form a resist film.
As the base material component, an organic compound having a molecular weight of 500 or more is generally used. When the molecular weight of the organic compound is 500 or more, the film-forming ability is improved and a nano-level resist pattern is easily formed.
“Organic compounds having a molecular weight of 500 or more” used as the base component are roughly classified into non-polymers and polymers.
As the non-polymer, those having a molecular weight of 500 or more and less than 4000 are usually used. Hereinafter, a nonpolymer having a molecular weight of 500 or more and less than 4000 is referred to as a low molecular compound.
As the polymer, those having a molecular weight of 1000 or more are usually used. Hereinafter, a polymer having a molecular weight of 1000 or more may be simply referred to as “resin”. In the case of a resin, as the “molecular weight”, a mass average molecular weight in terms of polystyrene by GPC (gel permeation chromatography) is used.
Conventionally, a resin is generally used as a base component of a resist composition.

<(A) component>
When the chemically amplified resist composition is a negative resist composition, as the component (A), a base component soluble in an alkali developer is used, and a crosslinking agent is further blended. In such a negative resist composition, when an acid is generated from the component (B) by exposure, the acid acts to cause crosslinking between the base material component and the crosslinking agent, resulting in poor solubility in an alkali developer. To do. Therefore, in the formation of the resist pattern, when the resist film obtained by applying the negative resist composition on the substrate is selectively exposed, the exposed portion turns into poorly soluble in an alkaline developer, while unexposed. Since the portion remains soluble in the alkali developer and does not change, a resist pattern can be formed by alkali development.
As the component (A) of the negative resist composition, a resin that is soluble in an alkali developer (hereinafter referred to as an alkali-soluble resin) is usually used.
Examples of the alkali-soluble resin include α- (hydroxyalkyl) acrylic acid or alkyl esters of α- (hydroxyalkyl) acrylic acid (preferably alkyl having 1 to 5 carbon atoms) disclosed in JP-A No. 2000-206694. Resin having a unit derived from at least one selected from ester), (meth) acrylic resin or polycycloolefin resin having a sulfonamide group, disclosed in US Pat. No. 6,949,325, US Pat. (Meth) acrylic resin containing a fluorinated alcohol, disclosed in JP-A No. 2005-336442, JP-A-2006-317803, and polycycloolefin resin having a fluorinated alcohol disclosed in JP-A-2006-259582 Etc. Good with little swelling A resist pattern can be formed, which is preferable. The α- (hydroxyalkyl) acrylic acid is composed of acrylic acid in which a hydrogen atom is bonded to the α-position carbon atom to which the carboxy group is bonded, and a hydroxyalkyl group (preferably having a carbon number) in the α-position carbon atom. One or both α-hydroxyalkylacrylic acids to which 1-5 hydroxyalkyl groups) are bonded.
As the crosslinking agent, for example, it is usually preferable to use an amino crosslinking agent such as glycoluril having a methylol group or an alkoxymethyl group, a melamine crosslinking agent, or the like because a good resist pattern with less swelling can be formed.
It is preferable that the compounding quantity of a crosslinking agent is 1-50 mass parts with respect to 100 mass parts of alkali-soluble resin.

When the chemically amplified resist composition is a positive resist composition, as the component (A), a base material component whose solubility in an alkaline developer is increased by the action of an acid is used.
Such a positive resist composition is poorly soluble in an alkali developer before exposure, and when an acid is generated from the component (B) by exposure, the component (A) is insensitive to the alkali developer by the action of the acid. It turns into soluble. Therefore, in the formation of the resist pattern, when the resist film formed using the positive resist composition is selectively exposed, the exposed portion turns soluble in an alkali developer, while the unexposed portion is Since it remains hardly soluble in the alkali developer, the exposed portion is removed by alkali development, and a resist pattern is formed.
The component (A) may be a resin component (A1) (hereinafter also referred to as component (A1)) whose solubility in an alkaline developer is increased by the action of an acid. It may be a low molecular compound (A2) (hereinafter sometimes referred to as the component (A2)) whose solubility in a liquid is increased, or a mixture thereof.
Hereinafter, preferred embodiments of the component (A1) and the component (A2) will be described more specifically.

[(A1) component]
Component (A1) is proposed as a base resin for conventional chemically amplified KrF positive resist compositions, ArF positive resist compositions, EB positive resist compositions, EUV positive resist compositions, etc. Among these, it can be appropriately selected according to the type of exposure light source used when forming the resist pattern.
As the base resin, a resin having a structural unit containing an acid dissociable, dissolution inhibiting group is usually used. Examples of the resin include novolak resins, polyhydroxystyrene resins (for example, the later-described (A12) component), Examples thereof include acrylic resins (for example, (A11) component described later).
Here, the acid dissociable, dissolution inhibiting group is acid dissociable that can be dissociated by the action of an acid generated from the component (B), and the entire component (A) before the dissociation is hardly soluble in an alkali developer. It is a group having alkali dissolution inhibiting properties. Therefore, in the component (A), when an acid is generated from the component (B) by exposure, the acid dissociable, dissolution inhibiting group is dissociated by the action of the acid, and as a result, the entire component (A) changes to alkali-soluble. .
As the acid dissociable, dissolution inhibiting group, those proposed so far as the acid dissociable, dissolution inhibiting group of the base resin for chemically amplified resist can be used. In general, a group that forms a cyclic or chain tertiary alkyl ester with a carboxy group in (meth) acrylic acid or the like; an acetal-type acid dissociable, dissolution inhibiting group such as an alkoxyalkyl group is widely known. . The “(meth) acrylic acid ester” means one or both of an acrylic acid ester having a hydrogen atom bonded to the α-position and a methacrylic acid ester having a methyl group bonded to the α-position.
Here, the “tertiary alkyl ester” is an ester formed by replacing a hydrogen atom of a carboxy group with a chain or cyclic alkyl group, and the carbonyloxy group (—C (O)). A structure in which the tertiary carbon atom of the chain or cyclic alkyl group is bonded to the terminal oxygen atom of -O-). In this tertiary alkyl ester, when an acid acts, a bond is cut between an oxygen atom and a tertiary carbon atom.
The chain or cyclic alkyl group may have a substituent.
Hereinafter, a group that is acid dissociable by constituting a carboxy group and a tertiary alkyl ester is referred to as a “tertiary alkyl ester type acid dissociable, dissolution inhibiting group” for convenience.

Examples of the tertiary alkyl ester type acid dissociable, dissolution inhibiting group include an aliphatic branched acid dissociable, dissolution inhibiting group and an acid dissociable, dissolution inhibiting group containing an aliphatic cyclic group.
Here, “aliphatic branched” means having a branched structure without aromaticity. The structure of the “aliphatic branched acid dissociable, dissolution inhibiting group” is not limited to a group consisting of carbon and hydrogen (hydrocarbon group), but is preferably a hydrocarbon group. The “hydrocarbon group” may be either saturated or unsaturated, but is usually preferably saturated.
Examples of the aliphatic branched acid dissociable, dissolution inhibiting group include a group represented by -C (R ⁷¹ ) (R ⁷² ) (R ⁷³ ). ^Wherein, R 71 ^{to R 73} each independently represents a linear alkyl group of 1 to 5 carbon atoms. The group represented by —C (R ⁷¹ ) (R ⁷² ) (R ⁷³ ) preferably has 4 to 8 carbon atoms, specifically, a tert-butyl group or a 2-methyl-2-butyl group. 2-methyl-2-pentyl group, 3-methyl-3-pentyl group, and the like. A tert-butyl group is particularly preferable.

The “aliphatic cyclic group” means a monocyclic group or a polycyclic group having no aromaticity.
The aliphatic cyclic group may or may not have a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (= O). , Etc.
The basic ring structure excluding the substituent of the “aliphatic cyclic group” is not limited to a group consisting of carbon and hydrogen (hydrocarbon group), but is preferably a hydrocarbon group. The “hydrocarbon group” may be either saturated or unsaturated, but is usually preferably saturated.
Examples of the aliphatic cyclic group include one or more hydrogens from a monocycloalkane which may or may not be substituted with an alkyl group having 1 to 5 carbon atoms, a fluorine atom or a fluorinated alkyl group. Examples thereof include a group in which one or more hydrogen atoms have been removed from a polycycloalkane such as bicycloalkane, tricycloalkane, and tetracycloalkane. More specifically, a group obtained by removing one or more hydrogen atoms from a monocycloalkane such as cyclopentane or cyclohexane or one or more polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane or tetracyclododecane. And a group in which hydrogen atom is removed. Further, a part of carbon atoms constituting the ring of a group obtained by removing one or more hydrogen atoms from these monocycloalkanes or a group obtained by removing one or more hydrogen atoms from polycycloalkane is an etheric oxygen atom (- O-) may be substituted.
In the present invention, the aliphatic cyclic group is preferably a polycyclic group.

Examples of the acid dissociable, dissolution inhibiting group containing an aliphatic cyclic group include:
(I) a group having a tertiary carbon atom on the ring skeleton of a monovalent aliphatic cyclic group;
(Ii) a group having a monovalent aliphatic cyclic group and a branched alkylene having a tertiary carbon atom bonded thereto, and the like.
(I) Specific examples of the group having a tertiary carbon atom on the ring skeleton of the monovalent aliphatic cyclic group are represented by the following general formulas (1-1) to (1-9). Groups and the like.
(Ii) Specific examples of the group having a monovalent aliphatic cyclic group and a branched alkylene group having a tertiary carbon atom bonded thereto include, for example, the following general formulas (2-1) to (2-1) And the group represented by (2-6).

［式中、Ｒ^１４はアルキル基であり、ｇは０〜８の整数である。］

^{Wherein, R 14} represents an alkyl group, g is an integer of 0-8. ]

［式中、Ｒ^１５およびＲ^１６は、それぞれ独立してアルキル基である。］

[Wherein, R ¹⁵ and R ¹⁶ each independently represents an alkyl group. ]

The alkyl group for R ¹⁴ is preferably a linear or branched alkyl group.
The linear alkyl group preferably has 1 to 5 carbon atoms, more preferably 1 to 4, and still more preferably 1 or 2. Specific examples include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, and an n-pentyl group. Among these, a methyl group, an ethyl group or an n-butyl group is preferable, and a methyl group or an ethyl group is more preferable.
The branched alkyl group preferably has 3 to 10 carbon atoms, and more preferably 3 to 5 carbon atoms. Specific examples include isopropyl group, isobutyl group, tert-butyl group, isopentyl group, neopentyl group and the like, and isopropyl group is most preferable.
g is preferably an integer of 0 to 3, more preferably an integer of 1 to 3, and still more preferably 1 or 2.
Examples of the alkyl group for R ^{15 to} R ¹⁶ include the same alkyl groups as those for R ¹⁴ .
In the above formulas (1-1) to (1-9) and (2-1) to (2-6), some of the carbon atoms constituting the ring are substituted with etheric oxygen atoms (—O—). May be.
In formulas (1-1) to (1-9) and (2-1) to (2-6), a hydrogen atom bonded to a carbon atom constituting the ring may be substituted with a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a fluorine atom, and a fluorinated alkyl group.

The “acetal-type acid dissociable, dissolution inhibiting group” is generally bonded to an oxygen atom by substituting a hydrogen atom at the terminal of an alkali-soluble group such as a carboxy group or a hydroxyl group. When an acid is generated by exposure, the acid acts to break the bond between the acetal acid dissociable, dissolution inhibiting group and the oxygen atom to which the acetal acid dissociable, dissolution inhibiting group is bonded.
Examples of the acetal type acid dissociable, dissolution inhibiting group include a group represented by the following general formula (p1).

［式中、Ｒ^１’，Ｒ^２’はそれぞれ独立して水素原子または炭素数１〜５のアルキル基を表し、ｎは０〜３の整数を表し、Ｙは炭素数１〜５のアルキル基または脂肪族環式基を表す。］

[Wherein, R ¹ 'and R ² ' each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, n represents an integer of 0 to 3, and Y represents an alkyl group having 1 to 5 carbon atoms. Or represents an aliphatic cyclic group. ]

In the formula (p1), n is preferably an integer of 0 to 2, more preferably 0 or 1, and most preferably 0.
Examples of the alkyl group having 1 to 5 carbon atoms of R ¹ ′ and R ² ′ include the same alkyl groups as those described above for R. A methyl group or an ethyl group is preferable, and a methyl group is most preferable.
In the present invention, it is preferable that at least one of R ¹ ′ and R ² ′ is a hydrogen atom. That is, the acid dissociable, dissolution inhibiting group (p1) is preferably a group represented by the following general formula (p1-1).

［式中、Ｒ^１’、ｎ、Ｙは上記と同じである。］

[Wherein R ¹ ′, n and Y are the same as described above. ]

Examples of the alkyl group for Y include the same alkyl groups as those described above for R.
The aliphatic cyclic group for Y can be appropriately selected from monocyclic or polycyclic aliphatic cyclic groups conventionally proposed in a number of ArF resists and the like. For example, the above “aliphatic ring” Examples thereof are the same as those in the formula group.

  Examples of the acetal type acid dissociable, dissolution inhibiting group also include a group represented by the following general formula (p2).

［式中、Ｒ^１７、Ｒ^１８はそれぞれ独立して直鎖状若しくは分岐鎖状のアルキル基または水素原子であり；Ｒ^１９は直鎖状、分岐鎖状若しくは環状のアルキル基である。または、Ｒ^１７およびＲ^１９がそれぞれ独立に直鎖状若しくは分岐鎖状のアルキレン基であって、Ｒ^１７の末端とＲ^１９の末端とが結合して環を形成していてもよい。］

[Wherein, R ¹⁷ and R ¹⁸ each independently represents a linear or branched alkyl group or a hydrogen atom; and R ¹⁹ represents a linear, branched or cyclic alkyl group. Alternatively, R ¹⁷ and R ¹⁹ may be each independently a linear or branched alkylene group, and the end of R ^{17 and} the end of R ¹⁹ may be bonded to form a ring. ]

In R ¹⁷ and R ¹⁸ , the alkyl group preferably has 1 to 15 carbon atoms, may be linear or branched, and is preferably an ethyl group or a methyl group, and most preferably a methyl group.
In particular, it is preferable that one of R ¹⁷ and R ¹⁸ is a hydrogen atom and the other is a methyl group.
R ¹⁹ is a linear, branched or cyclic alkyl group, preferably having 1 to 15 carbon atoms, and may be any of linear, branched or cyclic.
When R ¹⁹ is linear or branched, it preferably has 1 to 5 carbon atoms, more preferably an ethyl group or a methyl group, and most preferably an ethyl group.
When R ¹⁹ is cyclic, it preferably has 4 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, one or more polycycloalkanes such as monocycloalkane, bicycloalkane, tricycloalkane, tetracycloalkane, which may or may not be substituted with a fluorine atom or a fluorinated alkyl group. And the like, in which a hydrogen atom is removed. Specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among them, a group obtained by removing one or more hydrogen atoms from adamantane is preferable.
In the above formula ^(p2), a ^{R 17} and ^{R 19} are each independently a linear or branched alkylene group (preferably an alkylene group having 1 to 5 carbon ^atoms), and the terminal of ^{R 19} The terminal of R ¹⁷ may be bonded.
In this case, a cyclic group is formed by R ¹⁷ , R ¹⁹ , the oxygen atom to which R ¹⁹ is bonded, and the carbon atom to which the oxygen atom and R ¹⁷ are bonded. The cyclic group is preferably a 4-7 membered ring, and more preferably a 4-6 membered ring. Specific examples of the cyclic group include a tetrahydropyranyl group and a tetrahydrofuranyl group.

  Specific examples of the acetal type acid dissociable, dissolution inhibiting group include groups represented by the following formulas (p3-1) to (p3-12).

［式中、Ｒ^１３は水素原子またはメチル基であり、ｇは前記と同じである。］

[Wherein, R ¹³ represents a hydrogen atom or a methyl group, and g is the same as defined above. ]

More specifically, examples of the structural unit containing an acid dissociable, dissolution inhibiting group include structural units (a1) and (a7) described later.
The component (A1) may contain a constituent unit other than the constituent unit containing an acid dissociable, dissolution inhibiting group. As the other structural unit, any structural unit proposed for use in a base resin for a chemically amplified resist can be used. Examples of the structural unit include structural units (a2) to (a7) described later. ) And the like.

-Structural unit (a1):
The structural unit (a1) is a structural unit derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group.
The acid dissociable, dissolution inhibiting group in the structural unit (a1) has an alkali dissolution inhibiting property that makes the entire component (A1) hardly soluble in an alkali developer before dissociation, and an acid generated by exposure from an acid generator. To increase the solubility of the entire component (A1) in an alkaline developer.

Here, the “structural unit derived from an acrylate ester” means a structural unit formed by cleavage of an ethylenic double bond of an acrylate ester.
“Acrylic acid esters” include those in which a hydrogen atom is bonded to the carbon atom at the α-position, and those in which a substituent (atom or group other than a hydrogen atom) is bonded to the carbon atom in the α-position. Include concepts. Examples of the substituent include an alkyl group and a halogenated alkyl group. Note that the α-position (α-position carbon atom) of a structural unit derived from an acrylate ester means a carbon atom to which a carbonyl group is bonded, unless otherwise specified.
The alkyl group as a substituent bonded to the α-position carbon atom is preferably an alkyl group having 1 to 5 carbon atoms, specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, Examples thereof include linear or branched alkyl groups such as isobutyl group, tert-butyl group, pentyl group, isopentyl group, and neopentyl group.
Specific examples of the halogenated alkyl group include groups in which some or all of the hydrogen atoms of the alkyl group have been substituted with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable.
In the structural unit derived from an acrylate ester, the α-position of the acrylate ester is bonded to a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. It is more preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms, and from the viewpoint of industrial availability, it is preferably a hydrogen atom or a methyl group. Most preferred.

Examples of the acid dissociable, dissolution inhibiting group in the structural unit (a1) include the same groups as described above.
As the structural unit (a1), one or more selected from the group consisting of structural units represented by the following general formula (a1-0-1) and structural units represented by the following general formula (a1-0-2): Is preferably used.

［式中、Ｒは水素原子、炭素数１〜５のアルキル基またはハロゲン化アルキル基を示し；Ｘ^１およびＸ^２はそれぞれ独立に酸解離性溶解抑制基を示し；Ｙ^２は２価の連結基を示す。］

[Wherein, R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group; X ¹ and X ² each independently represent an acid dissociable, dissolution inhibiting group; Y ² represents a divalent linkage. Indicates a group. ]

In General Formula (a1-0-1), the alkyl group having 1 to 5 carbon atoms or the halogenated alkyl group represented by R is an alkyl group having 1 to 5 carbon atoms that may be bonded to the α-position of the acrylate ester or The thing similar to what was mentioned as a halogenated alkyl group is mentioned.
X ¹ is not particularly limited as long as it is an acid dissociable, dissolution inhibiting group, and examples thereof include the above-described tertiary alkyl ester type acid dissociable, dissolution inhibiting group and acetal type acid dissociable, dissolution inhibiting group. And tertiary alkyl ester type acid dissociable, dissolution inhibiting groups are preferred.
In general formula (a1-0-2), R is the same as defined above.
X ² is the same as X ¹ in formula (a1-0-1).

Preferred examples of Y ² include a divalent hydrocarbon group which may have a substituent, a divalent linking group containing a hetero atom, and the like.
In the “divalent hydrocarbon group optionally having substituent (s)” in Y ^2, the hydrocarbon group has “substituent” means that part or all of the hydrogen atoms in the hydrocarbon group are It means substituted with a group or atom other than a hydrogen atom.
The hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. An aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity.
The aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated.
More specifically, examples of the aliphatic hydrocarbon group include a linear or branched aliphatic hydrocarbon group, an aliphatic hydrocarbon group containing a ring in the structure, and the like.

The linear or branched aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 8, more preferably 1 to 5, and most preferably 1 to 2.
As the linear aliphatic hydrocarbon group, a linear alkylene group is preferable. Specifically, a methylene group [—CH ₂ —], an ethylene group [— (CH ₂ ) ₂ —], a trimethylene group [ — (CH ₂ ) ₃ —], tetramethylene group [— (CH ₂ ) ₄ —], pentamethylene group [— (CH ₂ ) ₅ —] and the like can be mentioned.
As the branched aliphatic hydrocarbon group, a branched alkylene group is preferred, and specifically, —CH (CH ₃ ) —, —CH (CH ₂ CH ₃ ) —, —C (CH ₃ ). Alkylmethylene groups such as _2- , —C (CH ₃ ) (CH ₂ CH ₃ ) —, —C (CH ₃ ) (CH ₂ CH ₂ CH ₃ ) —, —C (CH ₂ CH ₃ ) ₂ —; _{CH (CH 3) CH 2 -} , - CH (CH 3) CH (CH 3) -, - C (CH 3) 2 CH 2 -, - CH (CH 2 CH 3) CH 2 -, - C (CH 2 CH _{3) 2} -CH ₂ - alkyl groups such _{as; -CH (CH 3) CH 2} CH 2 -, - CH 2 CH (CH 3) CH 2 - alkyl trimethylene groups such as; -CH _(CH 3) _{CH 2 CH 2 CH 2 -,} - CH 2 CH (CH 3) CH 2 CH 2 - And the like alkyl alkylene group such as an alkyl tetramethylene group of. The alkyl group in the alkyl alkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.
The linear or branched aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (= O).

Examples of the aliphatic hydrocarbon group containing a ring in the structure include a cyclic aliphatic hydrocarbon group (a group obtained by removing two hydrogen atoms from an aliphatic hydrocarbon ring), and the cyclic aliphatic hydrocarbon group described above. Examples thereof include a group bonded to the terminal of a chain aliphatic hydrocarbon group or interposed in the middle of a chain aliphatic hydrocarbon group.
The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms.
The cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. As the monocyclic group, a group in which two hydrogen atoms have been removed from a monocycloalkane having 3 to 6 carbon atoms is preferable, and examples of the monocycloalkane include cyclopentane and cyclohexane.
As the polycyclic group, a group in which two hydrogen atoms are removed from a polycycloalkane having 7 to 12 carbon atoms is preferable. Specific examples of the polycycloalkane include adamantane, norbornane, isobornane, tricyclodecane, tetra And cyclododecane.
The cyclic aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (= O).

Examples of the aromatic hydrocarbon group include aromatics of monovalent aromatic hydrocarbon groups such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, and a phenanthryl group. A divalent aromatic hydrocarbon group obtained by removing one hydrogen atom from the nucleus of the aromatic hydrocarbon;
An aromatic hydrocarbon group in which a part of carbon atoms constituting the ring of the divalent aromatic hydrocarbon group is substituted with a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom;
An arylalkyl group such as benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, etc., and a hydrogen atom from the nucleus of the aromatic hydrocarbon Further, an aromatic hydrocarbon group from which one is removed;
The aromatic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (= O).

The hetero atom in the “divalent linking group containing a hetero atom” is an atom other than a carbon atom and a hydrogen atom, and examples thereof include an oxygen atom, a nitrogen atom, a sulfur atom, and a halogen atom.
Specific examples of the divalent linking group containing a hetero atom include —O—, —C (═O) —, —C (═O) —O—, and a carbonate bond (—O—C (═O) —. O—), —NH—, —NR ⁰⁴ (R ⁰⁴ is an alkyl group) —, —NH—C (═O) —, ═N— and the like. Moreover, the combination etc. of these "divalent coupling groups containing a hetero atom" and a bivalent hydrocarbon group are mentioned. Examples of the divalent hydrocarbon group include the same hydrocarbon groups that may have a substituent as described above, and a linear or branched aliphatic hydrocarbon group is preferable.

In the present invention, the divalent linking group for Y ² is preferably an alkylene group, a divalent aliphatic cyclic group or a divalent linking group containing a hetero atom. Among these, an alkylene group is particularly preferable.
When Y ² is an alkylene group, the alkylene group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms. It is most preferable that it is number 1-3. Specific examples include the same linear alkylene groups and branched alkylene groups as mentioned above.
When Y ² is a divalent aliphatic cyclic group, the aliphatic cyclic group is the same as the cyclic aliphatic hydrocarbon group mentioned in the above “aliphatic hydrocarbon group containing a ring in the structure”. Can be mentioned.
The aliphatic cyclic group is particularly preferably a group in which two or more hydrogen atoms have been removed from cyclopentane, cyclohexane, norbornane, isobornane, adamantane, tricyclodecane or tetracyclododecane.

When Y ² is a divalent linking group containing a hetero atom, preferred examples of the linking group include —O—, —C (═O) —O—, —C (═O) —, and —O—C. (═O) —O—, —C (═O) —NH—, —NH— (H may be substituted with a substituent such as an alkyl group or an acyl group), —S—, —S ( ═O) ₂ —, —S (═O) ₂ —O—, a group represented by the general formula —A—O—B—, a general formula — [A—C (═O) —O] _d —B— The group etc. which are represented by these are mentioned. Here, A and B are each independently a divalent hydrocarbon group which may have a substituent, and d is an integer of 0 to 3.
When Y ² is —NH—, H may be substituted with a substituent such as an alkyl group or an acyl group. The substituent (alkyl group, acyl group, etc.) preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and particularly preferably 1 to 5 carbon atoms.

In the general formula —A—O—B— or — [A—C (═O) —O] _d —B—, each of A and B independently represents a divalent group that may have a substituent. It is a hydrocarbon group.
Examples of the divalent hydrocarbon group which may have a substituent in A and B are the same as those described above as the “divalent hydrocarbon group which may have a substituent” in R ² . Can be mentioned.
As A, a linear aliphatic hydrocarbon group is preferable, a linear alkylene group is more preferable, a linear alkylene group having 1 to 5 carbon atoms is more preferable, and a methylene group or an ethylene group is particularly preferable. .
B is preferably a linear or branched aliphatic hydrocarbon group, more preferably a methylene group, an ethylene group or an alkylmethylene group. The alkyl group in the alkylmethylene group is preferably a linear alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group having 1 to 3 carbon atoms, and most preferably a methyl group.
In the group represented by the formula — [A—C (═O) —O] _d —B—, d is an integer of 0 to 3, preferably an integer of 0 to 2, and 0 or 1 is more. Preferably 1 is most preferred.

  More specifically, examples of the structural unit (a1) include structural units represented by the following general formulas (a1-1) to (a1-4).

［式中、Ｘ’は第３級アルキルエステル型酸解離性溶解抑制基を表し、Ｙは炭素数１〜５のアルキル基、または脂肪族環式基を表し；ｎは０〜３の整数を表し；Ｙ^２は２価の連結基を表し；Ｒは前記と同じであり、Ｒ^１’、Ｒ^２’はそれぞれ独立して水素原子または炭素数１〜５のアルキル基を表す。］

[Wherein, X ′ represents a tertiary alkyl ester-type acid dissociable, dissolution inhibiting group, Y represents an alkyl group having 1 to 5 carbon atoms, or an aliphatic cyclic group; n represents an integer of 0 to 3; Y ² represents a divalent linking group; R is the same as defined above; R ¹ ′ and R ² ′ each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. ]

Wherein, X 'include the same tertiary alkyl ester-type acid dissociable, dissolution inhibiting groups as those described above for X ^{1.
R 1 ', R 2',} n, as the Y, respectively, ^{R 1} in the general formula listed in the description of "acetal-type acid dissociable, dissolution inhibiting group" described above ^{(p1) ', R 2'} , n, Y The same thing is mentioned.
The Y ^2, the same groups as those described above for ^{Y 2} in the general formula (a1-0-2).
Specific examples of the structural units represented by the general formulas (a1-1) to (a1-4) are shown below.
In the following formulas, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

As the structural unit (a1), one type may be used alone, or two or more types may be used in combination.
Among the above, the structural unit represented by the general formula (a1-1) or (a1-3) is preferable, and specifically, (a1-1-1) to (a1-1-4), (a1-1) −20) to (a1-1-23) and (a1-3-25) to (a1-3-28) are used, and at least one selected from the group consisting of structural units represented by any one of them is used. More preferred.
Furthermore, as the structural unit (a1), in particular, the following general formula (a1-1-01) including the structural units represented by any of the formulas (a1-1-1) to (a1-1-3) And structural units represented by any of formulas (a1-1-16) to (a1-1-17) and formulas (a1-1-20) to (a1-1-23) The following general formula (a1) including the structural unit represented by any of the following general formula (a1-1-02) and any of formulas (a1-3-25) to (a1-3-26) -3-01), or the following general formula (a1-3-02) including structural units represented by any of formulas (a1-3-27) to (a1-3-28) What is represented by these is also preferable. Moreover, the following general formula including the structural unit represented by any one of the formulas (a1-3-13) to (a1-3-24) and (a1-3-29) to (a1-3-32) What is represented by (a1-3-03) is also preferable.

［式中、Ｒは前記と同じであり、Ｒ^１１は炭素数１〜５のアルキル基であり、Ｒ^１２は炭素数１〜５のアルキル基であり、ｈは１〜６の整数である。］

[Wherein, R is the same as above, R ¹¹ is an alkyl group having 1 to 5 carbon atoms, R ¹² is an alkyl group having 1 to 5 carbon atoms, and h is an integer of 1 to 6]. ]

In general formula (a1-1-01), R is the same as defined above.
As the alkyl group for R ^11, a linear or branched alkyl group is preferable, and examples thereof include the same alkyl groups as those described above for R. R ¹⁴ is preferably a methyl group, an ethyl group or an isopropyl group.
In general formula (a1-1-02), R is the same as defined above.
As the alkyl group for R ^12, a linear or branched alkyl group is preferable, and examples thereof include the same alkyl groups as those described above for R. R ¹⁴ is preferably a methyl group, an ethyl group or an isopropyl group.
h is preferably 1 or 2, and most preferably 2.

［式中、Ｒおよび前期と同様水素原子、炭素数１〜５のアルキル基またはハロゲン化アルキル基を示し；Ｒ^１４はアルキル基であり、Ｒ^１３は水素原子またはメチル基であり、ａは１〜１０の整数であり、ｎ’は１〜６の整数である。］

[Wherein, R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group as in the previous period; R ¹⁴ represents an alkyl group, R ¹³ represents a hydrogen atom or a methyl group, and a represents 1 Is an integer of -10, and n 'is an integer of 1-6. ]

In the general formula (a1-3-01) or (a1-3-02), R is the same as described above.
R ¹³ is preferably a hydrogen atom.
The alkyl group for R ¹⁴ is preferably a linear or branched alkyl group, and examples thereof include the same alkyl groups as those described above for R. R ¹⁴ is preferably a methyl group, an ethyl group or an isopropyl group.
a is preferably an integer of 1 to 8, more preferably an integer of 2 to 5, and most preferably 2.

［式中、ＲおよびＸ^２はそれぞれ前記と同じであり、Ｙ^２’およびＹ^２”はそれぞれ独立して２価の連結基であり、ｎ”は０〜３の整数である。］

[Wherein, R and X ² are the same as defined above, Y ² ′ and Y ² ″ are each independently a divalent linking group, and n ″ is an integer of 0 to 3. ]

In formula (a1-3-03), examples of the divalent linking group for Y ² ′ and Y ² ″ include the same groups as those described above for Y ² .
Y ² ′ is preferably a divalent hydrocarbon group which may have a substituent, more preferably a linear aliphatic hydrocarbon group, and still more preferably a linear alkylene group. Among these, a linear alkylene group having 1 to 5 carbon atoms is preferable, and a methylene group or an ethylene group is most preferable.
Y ² ″ is preferably a divalent hydrocarbon group which may have a substituent, more preferably a linear aliphatic hydrocarbon group, and still more preferably a linear alkylene group. A linear alkylene group of 1 to 5 is preferable, and a methylene group and an ethylene group are most preferable.
Examples of the acid dissociable, dissolution inhibiting group for X ² are the same as those described above.
X ² in formula (a1-3-03) is preferably a tertiary alkyl ester-type acid dissociable, dissolution inhibiting group, and the above-mentioned (i) the third group on the ring skeleton of the monovalent aliphatic cyclic group. A group having a secondary carbon atom is more preferable, and a group in which the aliphatic cyclic group is a polycyclic group (aliphatic polycyclic group) is particularly preferable. Among these, a group represented by the general formula (1-1) is preferable.
n ″ is an integer of 0 to 3, preferably an integer of 0 to 2, more preferably 0 or 1, and most preferably 0.

Structural unit (a2):
The structural unit (a2) is a structural unit derived from an acrylate ester containing a lactone-containing cyclic group.
Here, the lactone-containing cyclic group refers to a cyclic group containing one ring (lactone ring) containing an —O—C (O) — structure. The lactone ring is counted as the first ring. When only the lactone ring is present, it is called a monocyclic group. When it has another ring structure, it is called a polycyclic group regardless of the structure.
When the component (A1) is used for forming a resist film, the lactone cyclic group of the structural unit (a2) increases the adhesion of the resist film to the substrate or has an affinity for a developer containing water. It is effective in raising.
As the structural unit (a2), any unit can be used without any particular limitation.
Specifically, the lactone-containing monocyclic group is a group in which one hydrogen atom is removed from a 4- to 6-membered ring lactone, for example, a group in which one hydrogen atom is removed from β-propionolactone, or γ-butyrolactone. Examples thereof include a group in which one hydrogen atom has been removed, and a group in which one hydrogen atom has been removed from δ-valerolactone. Examples of the lactone-containing polycyclic group include groups in which one hydrogen atom has been removed from a bicycloalkane, tricycloalkane, or tetracycloalkane having a lactone ring.
More specifically, examples of the structural unit (a2) include structural units represented by general formulas (a2-1) to (a2-5) shown below.

［式中、Ｒは水素原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基であり；Ｒ’はそれぞれ独立に水素原子、炭素数１〜５のアルキル基、炭素数１〜５のアルコキシ基または−ＣＯＯＲ”であり、Ｒ”は水素原子またはアルキル基であり；Ｒ^２９は単結合または２価の連結基であり、ｓ”は０〜２の整数であり；Ａ”は酸素原子もしくは硫黄原子を含んでいてもよい炭素数１〜５のアルキレン基、酸素原子または硫黄原子であり；ｍは０または１である。］

[Wherein, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms; R ′ is independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, carbon An alkoxy group of 1 to 5 or —COOR ″, R ″ is a hydrogen atom or an alkyl group; R ²⁹ is a single bond or a divalent linking group, and s ″ is an integer of 0 to 2; A ″ is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom or a sulfur atom; m is 0 or 1. ]

R in the general formulas (a2-1) to (a2-5) is the same as R in the structural unit (a1).
Examples of the alkyl group having 1 to 5 carbon atoms of R ′ include a methyl group, an ethyl group, a propyl group, an n-butyl group, and a tert-butyl group.
Examples of the alkoxy group having 1 to 5 carbon atoms of R ′ include a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, and a tert-butoxy group.
R ′ is preferably a hydrogen atom in view of industrial availability.
The alkyl group in R ″ may be linear, branched or cyclic.
When R ″ is a linear or branched alkyl group, it preferably has 1 to 10 carbon atoms, and more preferably 1 to 5 carbon atoms.
When R ″ is a cyclic alkyl group, it preferably has 3 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, a fluorine atom Or a group in which one or more hydrogen atoms are removed from a polycycloalkane such as monocycloalkane, bicycloalkane, tricycloalkane, tetracycloalkane, which may or may not be substituted with a fluorinated alkyl group Specifically, a group in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane, or a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Etc.
Examples of A ″ include the same as A ′ in the general formula (3-1). A ″ represents an alkylene group having 1 to 5 carbon atoms, an oxygen atom (—O—) or a sulfur atom (— S-) is preferable, and an alkylene group having 1 to 5 carbon atoms or -O- is more preferable. The alkylene group having 1 to 5 carbon atoms is more preferably a methylene group or a dimethylmethylene group, and most preferably a methylene group.

R ²⁹ is a single bond or a divalent linking group. Examples of the divalent linking group include the same divalent linking groups as those described above for R ² in the general formula (a0-1) can be given. Among these, an alkylene group, an ester bond (—C (═O) —O—), or a combination thereof is preferable. The alkylene group as the divalent linking group for R ²⁹ is more preferably a linear or branched alkylene group. Specifically, the same as the linear alkylene group and the branched alkylene group mentioned as the aliphatic hydrocarbon group for R ² can be used.
As R ²⁹ , in particular, a single bond or —R ²⁹ ′ —C (═O) —O— [wherein R ²⁹ ′ is a linear or branched alkylene group. ] Is preferable.
The linear or branched alkylene group for R ²⁹ ′ preferably has 1 to 10 carbon atoms, more preferably 1 to 8, more preferably 1 to 5, particularly preferably 1 to 3. ~ 2 is most preferred.
As the linear alkylene group for R ²⁹ ′, a methylene group or an ethylene group is preferable, and a methylene group is particularly preferable. The branched alkylene group for R ²⁹ ′ is preferably an alkylmethylene group or an alkylethylene group, and —CH (CH ₃ ) —, —C (CH ₃ ) ₂ — or —C (CH ₃ ) ₂ CH ₂ — Is particularly preferred.
In formula (a2-1), s ″ is preferably 1 to 2.
Specific examples of the structural units represented by the general formulas (a2-1) to (a2-5) are shown below. In the following formulas, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

In the component (A1), as the structural unit (a2), one type may be used alone, or two or more types may be used in combination.
In the present invention, the component (A1) is at least one selected from the group consisting of structural units represented by any one of the general formulas (a2-1) to (a2-5) as the structural unit (a2). It is preferable that at least one selected from the group consisting of structural units represented by any one of the general formulas (a2-1) to (a2-3) is more preferable. It is particularly preferable to have at least one selected from the group consisting of structural units represented by 1) or (a2-2).

-Structural unit (a3):
The structural unit (a3) is a structural unit derived from an acrylate ester containing a polar group-containing aliphatic hydrocarbon group.
When the component (A1) has the structural unit (a3), the hydrophilicity of the component (A) is increased, the affinity with the developer is increased, the alkali solubility in the exposed area is improved, and the resolution is improved. Contributes to improvement.
Examples of the polar group include a hydroxyl group, a cyano group, a carboxy group, and a fluorinated alcohol group (a hydroxyalkyl group in which a part of the hydrogen atoms of the alkyl group is substituted with a fluorine atom). A hydroxyl group is particularly preferable.
In the structural unit (a3), the number of polar groups bonded to the aliphatic hydrocarbon group is not particularly limited, but is preferably 1 to 3, and most preferably 1.
The aliphatic hydrocarbon group to which the polar group is bonded may be saturated, unsaturated, or saturated.
Examples of the aliphatic hydrocarbon group include a linear or branched hydrocarbon group having 1 to 10 carbon atoms (preferably an alkylene group) and a polycyclic aliphatic hydrocarbon group (polycyclic group). It is done. As the polycyclic group, for example, a resin for a resist composition for ArF excimer laser can be appropriately selected from among many proposed ones. The polycyclic group preferably has 7 to 30 carbon atoms.
Among them, a structural unit derived from an acrylate ester containing an aliphatic polycyclic group containing a hydroxyalkyl group in which a part of hydrogen atoms of a hydroxyl group, a cyano group, a carboxy group, or an alkyl group is substituted with a fluorine atom Is more preferable. Examples of the polycyclic group include groups in which two or more hydrogen atoms have been removed from bicycloalkane, tricycloalkane, tetracycloalkane and the like. Specific examples include groups in which two or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among these polycyclic groups, there are groups in which two or more hydrogen atoms have been removed from adamantane, groups in which two or more hydrogen atoms have been removed from norbornane, and groups in which two or more hydrogen atoms have been removed from tetracyclododecane. Industrially preferable.

  The structural unit (a3) is derived from a hydroxyethyl ester of acrylic acid when the hydrocarbon group in the polar group-containing aliphatic hydrocarbon group is a linear or branched hydrocarbon group having 1 to 10 carbon atoms. The structural unit is preferred. When the hydrocarbon group is a polycyclic group, the structural unit represented by the following formula (a3-1), the structural unit represented by the formula (a3-2), and the formula (a3-3) And the like.

［式中、Ｒは前記に同じであり、ｊは１〜３の整数であり、ｋは１〜３の整数であり、ｔ’は１〜３の整数であり、ｌは１〜５の整数であり、ｓは１〜３の整数である。］

[Wherein, R is as defined above, j is an integer of 1 to 3, k is an integer of 1 to 3, t ′ is an integer of 1 to 3, and l is an integer of 1 to 5] And s is an integer of 1 to 3. ]

In formula (a3-1), j is preferably 1 or 2, and more preferably 1. When j is 2, it is preferable that the hydroxyl group is bonded to the 3rd and 5th positions of the adamantyl group. When j is 1, it is preferable that the hydroxyl group is bonded to the 3-position of the adamantyl group.
In formula (a3-2), k is preferably 1. The cyano group is preferably bonded to the 5th or 6th position of the norbornyl group.
In formula (a3-3), t ′ is preferably 1. l is preferably 1. s is preferably 1.
In formula (a3-3), the oxygen atom (—O—) of the carbonyloxy group is preferably bonded to the 2nd or 3rd position of the norbornane ring. The fluorinated alkyl alcohol group is preferably bonded to the 5th or 6th position of the norbornyl group.
As the structural unit (a3), one type may be used alone, or two or more types may be used in combination.

-Structural unit (a4):
The structural unit (a4) is a structural unit derived from other acrylate esters not classified into the above-described structural units (a1) to (a3).
As the structural unit (a4), for example, a structural unit derived from an acrylate ester containing a non-acid-dissociable aliphatic polycyclic group is preferable. Examples of the polycyclic group include those exemplified in the case of the structural unit (a1), and for ArF excimer laser and KrF excimer laser (preferably for ArF excimer laser). A number of hitherto known materials can be used as the resin component of the resist composition.
In particular, at least one selected from a tricyclodecyl group, an adamantyl group, a tetracyclododecyl group, an isobornyl group, and a norbornyl group is preferable in terms of industrial availability. These polycyclic groups may have a linear or branched alkyl group having 1 to 5 carbon atoms as a substituent.
Specific examples of the structural unit (a4) include those represented by the following general formulas (a4-1) to (a4-5).

［式中、Ｒは前記と同じである。］

[Wherein, R is the same as defined above. ]

-Structural unit (a5):
The structural unit (a5) is a structural unit derived from hydroxystyrene.
Here, “structural unit derived from hydroxystyrene” means a structural unit formed by cleavage of an ethylenic double bond of hydroxystyrene.
“Hydroxystyrene” refers to hydroxystyrene (= a compound in which at least one hydroxyl group is bonded to the benzene ring of vinylbenzene; hereinafter referred to as unsubstituted hydroxystyrene) as well as α of the unsubstituted hydroxystyrene. It is a concept that includes a hydrogen atom bonded to a carbon atom at the position substituted with a substituent (α-substituted hydroxystyrene) and derivatives thereof. That is, it is simply referred to as “hydroxystyrene”, and if not particularly limited, the “hydroxystyrene” may be any of unsubstituted hydroxystyrene, α-substituted hydroxystyrene, and derivatives thereof. The α-position carbon atom of hydroxystyrene means a carbon atom to which a benzene ring is bonded unless otherwise specified.
Examples of the substituent that may be bonded to the α-position carbon atom in the α-substituted hydroxystyrene include an alkyl group having 1 to 5 carbon atoms, and an alkyl group having 1 to 5 carbon atoms is particularly preferable. The alkyl group is preferably a linear or branched alkyl group, and specifically includes a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, and pentyl. Group, isopentyl group, neopentyl group and the like.
Examples of the derivative include compounds in which a substituent is bonded to the benzene ring of unsubstituted hydroxystyrene or α-substituted hydroxystyrene.

  Preferred examples of the structural unit (a5) include structural units represented by general formula (a5-1) shown below.

［式（ａ５−１）中、Ｒ’は水素原子または炭素数１〜５のアルキル基であり；Ｒ^６はハロゲン原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基であり；ｐは１〜３の整数であり；ｑは０〜４の整数であり、ｐ＋ｑは１〜５である。］

[In the formula (a5-1), R ′ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; R ⁶ is a halogen atom, an alkyl group having 1 to 5 carbon atoms or an alkyl halide having 1 to 5 carbon atoms; P is an integer of 1 to 3; q is an integer of 0 to 4, and p + q is 1 to 5. ]

In formula (a5-1), R ′ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.
Examples of the alkyl group for R ′ include the same groups as those described above for the alkylstyrene that may be bonded to the α-position carbon atom of the α-substituted hydroxystyrene.
R ′ is preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, particularly preferably a hydrogen atom or a methyl group.
p is an integer of 1 to 3, q is an integer of 0 to 4, and p + q is 1 to 5. However, p + q is 1-5.
p is most preferably 1.
q is preferably an integer of 0 to 2, more preferably 0 or 1, and industrially particularly preferably 0.

In formula (a5-1), the bonding position of the hydroxyl group in the phenyl group is not particularly limited. When p is 1, any of the o-position, m-position and p-position may be used, and the p-position is preferred because it is readily available and inexpensive. When p is 2 or 3, any bonding position can be combined.
Moreover, the bonding position of R ^{2 in} the phenyl group is not particularly limited. When q is 1, any of the o-position, m-position, and p-position may be used. When q is an integer greater than or equal to 2, arbitrary bond positions can be combined.
When q is an integer of 2 or more, the plurality of R ² may be the same or different from each other.

R ⁶ is a halogen atom, a halogenated alkyl group of 1 to 5 alkyl group or a C1-5 carbon.
Examples of the halogen atom for R ⁶ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable.
As the alkyl group for R ^6, the same alkyl groups as those for R ¹ can be used.
Examples of the halogenated alkyl group for R ^6, part or all of the hydrogen atoms in the alkyl group of the R ⁶ are mentioned group substituted by a halogen atom, Examples of the halogen atom, mentioned as the halogen atom of R ⁶ The thing similar to a thing is mentioned. The halogenated alkyl group for R ⁶ is preferably a fluorinated alkyl group.

  As the structural unit (a5), one type of structural unit may be used alone, or two or more types of structural units may be used in combination.

Structural unit (a6):
The structural unit (a6) is a structural unit derived from styrene.
Here, in the present specification, the “structural unit derived from styrene” means a structural unit formed by cleavage of an ethylenic double bond of styrene.
“Styrene” means styrene in a narrow sense (= vinylbenzene; hereinafter sometimes referred to as unsubstituted styrene), and a hydrogen atom bonded to the α-position carbon atom of the unsubstituted styrene is substituted with a substituent. The concept includes products (α-substituted styrene) and derivatives thereof. That is, it is simply referred to as “styrene”, and there is no particular limitation. The “styrene” may be any of unsubstituted styrene, α-substituted styrene, and derivatives thereof. The α-position carbon atom of styrene means a carbon atom to which a benzene ring is bonded unless otherwise specified.
In the α-substituted styrene, examples of the substituent which may be bonded to the α-position carbon atom include an alkyl group having 1 to 5 carbon atoms, and an alkyl group having 1 to 5 carbon atoms is particularly preferable. The alkyl group is preferably a linear or branched alkyl group, and specifically includes a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, and pentyl. Group, isopentyl group, neopentyl group and the like.
Examples of the derivative include those in which a substituent is bonded to the benzene ring of unsubstituted styrene or α-substituted styrene.
As the structural unit (a6), for example, a structural unit represented by general formula (a6-1) shown below can be exemplified.

［式（ａ６−１）中、Ｒ’は前記と同じであり；Ｒ^７はハロゲン原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基であり；ｒは０〜５の整数である。］
［式中、Ｒ^１は前記と同じであり、Ｒ^３はハロゲン原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基であり、ｒは０〜５の整数である。］

[In the formula (a6-1), R ′ is the same as above; R ⁷ is a halogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms; It is an integer of 5. ]
[Wherein, R ¹ is as defined above, R ³ is a halogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, and r is an integer of 0 to 5] . ]

In formula (a6-1), examples of R ′ and R ⁷ are the same as R ′ and R ^{6 in} formula (a5-1).
r is preferably an integer of 0 to 3, more preferably 0 or 1, and most preferably 0 industrially.
When r is 1, the substitution position of R ⁷ may be any of the o-position, m-position and p-position of the phenyl group.
When r is 2 or 3, any substitution position can be combined. The plurality of R ⁷ may be the same or different.
As the structural unit (a6), one type may be used alone, or two or more types may be used in combination.

-Structural unit (a7):
The structural unit (a7) is a structural unit derived from hydroxystyrene, and at least one of the hydrogen atoms of the hydroxyl group contained in the structural unit includes an acid dissociable, dissolution inhibiting group or an acid dissociable, dissolution inhibiting group. A structural unit substituted with an organic group.
As the structural unit (a7), it is preferable that the hydrogen atom of the hydroxyl group in the general formula (a5-1) is substituted with an acid dissociable, dissolution inhibiting group or an organic group containing an acid dissociable, dissolution inhibiting group. Is mentioned.
The acid dissociable, dissolution inhibiting group in the structural unit (a7) is not particularly limited, and may be appropriately selected from many proposed resins for resist compositions such as for KrF excimer laser and ArF excimer laser. Examples thereof include those similar to those exemplified in the structural unit (a1).
As preferred acid dissociable, dissolution inhibiting groups, specifically, tertiary alkyl groups exemplified below as acid dissociable, dissolution inhibiting groups (7-1) and the following acid dissociable, dissolution inhibiting group-containing groups (7-3) A containing group.
The organic group having an acid dissociable, dissolution inhibiting group is not particularly limited. For example, a resin for resist compositions such as for KrF excimer laser and ArF excimer laser is appropriately selected and used. be able to. Specific examples include organic groups having the acid dissociable, dissolution inhibiting groups listed above. Examples include the following acid dissociable, dissolution inhibiting groups as organic groups having an acid dissociable, dissolution inhibiting group (7-1). An organic group (7-2) having a tertiary alkyl group-containing group exemplified by the following acid dissociable, dissolution inhibiting group-containing group (7-3) (for example, a tertiary alkyl group, a tertiary alkyloxycarbonyl group, A tertiary alkyloxycarbonylalkyl group, etc.).

Acid dissociable, dissolution inhibiting group (7-1):
Examples of the acid dissociable, dissolution inhibiting group (7-1) include a group represented by the following general formula (7-1a) and a group represented by the following general formula (7-1b).

［式（７−１ａ）中、Ｒ^２７は直鎖状又は分岐鎖状のアルキレン基を表し；Ｘ^０は脂肪族環式基、芳香族環式炭化水素基又は炭素数１〜５のアルキル基を表す。式（７−１ｂ）中、Ｘ^０は前記式（７−１ａ）におけるＸ^０と同じであり；Ｒ^４は水素原子若しくは炭素数１〜５のアルキル基を表し、又は、Ｘ^０およびＲ^４がそれぞれ独立に炭素数１〜５のアルキレン基であって、Ｘ^０の末端とＲ^４の末端とが結合していてもよく；Ｒ^５は水素原子又は炭素数１〜５のアルキル基を表す。］

[In the formula (7-1a), R ²⁷ represents a linear or branched alkylene group; X ⁰ is an aliphatic cyclic group, an aromatic cyclic hydrocarbon group or an alkyl group having 1 to 5 carbon atoms. Represents. In Formula (7-1b), X ⁰ is the same as X ⁰ in Formula (7-1a); R ⁴ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, or X ⁰ and R ⁴ Each independently represents an alkylene group having 1 to 5 carbon atoms, and the end of X ⁰ may be bonded to the end of R ⁴ ; R ⁵ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. . ]

In the general formula (7-1a), R ²⁷ represents a linear or branched alkylene group.
The alkylene group preferably has 1 to 5 carbon atoms, more preferably 1 to 3 carbon atoms, and still more preferably 1 to 2 carbon atoms.
In the formulas (7-1a) and (7-1b), X ⁰ each independently represents an aliphatic cyclic group, an aromatic cyclic hydrocarbon group, or an alkyl group having 1 to 5 carbon atoms.
Here, the “aliphatic cyclic group” in the present specification and claims means a monocyclic group or a polycyclic group having no aromaticity, and is either saturated or unsaturated. Usually, it is usually preferable to be saturated.
The aliphatic cyclic group for X ⁰ is a monovalent aliphatic cyclic group. The aliphatic cyclic group can be appropriately selected from, for example, those proposed in a number of conventional ArF resists. Specific examples of the aliphatic cyclic group include an aliphatic monocyclic group having 5 to 7 carbon atoms and an aliphatic polycyclic group having 10 to 16 carbon atoms.
Examples of the aliphatic monocyclic group having 5 to 7 carbon atoms include groups in which one hydrogen atom has been removed from a monocycloalkane, specifically, one hydrogen atom has been removed from cyclopentane, cyclohexane and the like. Group.
Examples of the aliphatic polycyclic group having 10 to 16 carbon atoms include groups in which one hydrogen atom has been removed from bicycloalkane, tricycloalkane, tetracycloalkane and the like. Specific examples include groups in which one hydrogen atom has been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among these, an adamantyl group, a norbornyl group, and a tetracyclododecyl group are industrially preferable, and an adamantyl group is particularly preferable.
Examples of the aromatic cyclic hydrocarbon group for X ⁰ include aromatic polycyclic groups having 10 to 16 carbon atoms. Specific examples include groups in which one hydrogen atom has been removed from naphthalene, anthracene, phenanthrene, pyrene, and the like. Specific examples include 1-naphthyl group, 2-naphthyl group, 1-anthryl group, 2-anthryl group, 1-phenanthryl group, 2-phenanthryl group, 3-phenanthryl group, 1-pyrenyl group, and the like. A naphthyl group is particularly preferred industrially.
Examples of the alkyl group for X ⁰ include the same groups as the alkyl group for R ′ in the general formula (a5-1), more preferably a methyl group or an ethyl group, and most preferably an ethyl group.

In the formula (7-1b), examples of the alkyl group for R ⁴ include the same groups as the alkyl group for R ′ in the general formula (a5-1). Industrially, a methyl group or an ethyl group is preferable, and a methyl group is particularly preferable.
R ⁵ represents an alkyl group or a hydrogen atom. As the alkyl group for R ^5, the same alkyl groups as those for R ⁴ can be used. R ⁵ is preferably industrially a hydrogen atom.
In particular, it is preferable that either one of R ⁴ and R ⁵ is a hydrogen atom and the other is a methyl group.
In the general formula (7-1b), X ⁰ and R ⁴ are each independently an alkylene group having 1 to 5 carbon atoms, and the end of X ^{0 and} the end of R ⁴ are bonded to each other. Also good. In this case, in the general formula (7-1b), a cyclic group is formed by R ⁴ , X ⁰ , the oxygen atom to which X ⁰ is bonded, and the carbon atom to which the oxygen atom and R ⁴ are bonded. ing. The cyclic group is preferably a 4-7 membered ring, and more preferably a 4-6 membered ring. Specific examples of the cyclic group include a tetrahydropyranyl group and a tetrahydrofuranyl group.

As the acid dissociable, dissolution inhibiting group (7-1), R ⁵ is a hydrogen atom and R ⁴ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms because of excellent resist pattern shape and the like. Is preferred.
Specific examples of the acid dissociable, dissolution inhibiting group (7-1) include, for example, a group in which X ⁰ is an alkyl group, that is, a 1-alkoxyalkyl group such as a 1-methoxyethyl group, a 1-ethoxyethyl group, 1- Examples include iso-propoxyethyl group, 1-n-butoxyethyl group, 1-tert-butoxyethyl group, methoxymethyl group, ethoxymethyl group, iso-propoxymethyl group, n-butoxymethyl group, tert-butoxymethyl group, etc. It is done.
In addition, examples of the group in which X ⁰ is an aliphatic cyclic group include a 1-cyclohexyloxyethyl group, a 1- (2-adamantyl) oxymethyl group, and 1- (represented by the following formula (7-1-1). 1-adamantyl) oxyethyl group and the like.
Examples of the group in which X ⁰ is an aromatic cyclic hydrocarbon group include a 1- (2-naphthyl) oxyethyl group represented by the following formula (7-1-2).
Of these, a 1-ethoxyethyl group is particularly preferable.

Organic group having acid dissociable, dissolution inhibiting group (7-2):
Examples of the organic group (7-2) having an acid dissociable, dissolution inhibiting group include a group represented by the following general formula (7-2). In the organic group (7-2) having such a structure, when an acid is generated from the component (B1) by exposure, an oxygen atom bonded to Y and a carbon atom bonded to R ⁴ and R ⁵ are generated by the acid. broken bond ^{between, -C (R 4) (R} 5) -OX 0 dissociates.

［式（７−２）中、Ｘ^０は脂肪族環式基、芳香族環式炭化水素基または炭素数１〜５のアルキル基を表し；Ｒ^４は水素原子若しくはアルキル基を表し、又は、Ｘ^０およびＲ^４がそれぞれ独立に炭素数１〜５のアルキレン基であって、Ｘ^０の末端とＲ^４の末端とが結合していてもよく；Ｒ^５はアルキル基または水素原子を表し；Ｙは２価の脂肪族環式基を表す。］

[In Formula (7-2), X ⁰ represents an aliphatic cyclic group, an aromatic cyclic hydrocarbon group, or an alkyl group having 1 to 5 carbon atoms; R ⁴ represents a hydrogen atom or an alkyl group, or X ⁰ and R ⁴ are each independently an alkylene group having 1 to 5 carbon atoms, and the end of X ^{0 and} the end of R ⁴ may be bonded; R ⁵ represents an alkyl group or a hydrogen atom; Y represents a divalent aliphatic cyclic group. ]

In the general formula ^(7-2), as the X ^{0, R 4,} R ^5, respectively the same as ^{X 0, R 4,} R ⁵ in the general formula (7-1b).
Examples of the divalent aliphatic cyclic group for Y, include further groups in which one hydrogen atom has been removed from an aliphatic cyclic group for the X ^0.

Acid-dissociable, dissolution inhibiting group-containing group (7-3)
The acid dissociable, dissolution inhibiting group-containing group (7-3) includes the acid dissociable, dissolution inhibiting group (7-1) and the organic group (7-2) having an acid dissociable, dissolution inhibiting group (hereinafter collectively referred to as these). It is an acid dissociable, dissolution inhibiting group-containing group that is not classified as “acid dissociable, dissolution inhibiting group, etc. (7-1) to (7-2)”.
As the acid dissociable, dissolution inhibiting group-containing group (7-3), among the conventionally known acid dissociable, dissolution inhibiting group-containing groups, the above-mentioned acid dissociable, dissolution inhibiting groups, etc. (7-1) to (7-2) Any acid dissociable, dissolution inhibiting group-containing group that is not classified can be used.
Specific examples of the acid dissociable, dissolution inhibiting group-containing group (7-3) include a tertiary alkyl group-containing group.
Here, in the present specification, the “tertiary alkyl group” refers to an alkyl group having a tertiary carbon atom. As described above, the “alkyl group” represents a monovalent saturated hydrocarbon group, and includes a chain (straight chain or branched chain) alkyl group and an alkyl group having a cyclic structure.
The “tertiary alkyl group-containing group” refers to a group containing a tertiary alkyl group in its structure.
The tertiary alkyl group-containing group may be composed only of a tertiary alkyl group, or may be composed of a tertiary alkyl group and another atom or group other than the tertiary alkyl group. .
Examples of the “other atom or group other than the tertiary alkyl group” that constitutes the tertiary alkyl group-containing group together with the tertiary alkyl group include a carbonyloxy group, a carbonyl group, an alkylene group, and an oxygen atom. .

  Examples of the tertiary alkyl group-containing group include a tertiary alkyl group-containing group having no cyclic structure and a tertiary alkyl group-containing group having a cyclic structure.

The tertiary alkyl group-containing group having no cyclic structure is a group containing a branched tertiary alkyl group as the tertiary alkyl group and having no cyclic structure in the structure.
Examples of the branched tertiary alkyl group include a group represented by the following general formula (7-3a).

In formula (7-3a), R ^{21 to} R ²³ are each independently a linear or branched alkyl group. 1-5 are preferable and, as for carbon number of this alkyl group, 1-3 are more preferable.
Specific examples of the alkyl group having 1 to 5 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, and neopentyl group. Can be mentioned.
Moreover, as the general type total number of carbon atoms of the group represented by (7-3a) is 4 to 7, it is preferable to combine the above-described alkyl group ^R 21 ^{to R 23,} the total number of carbon atoms is 4 to 6 It is more preferable to combine the alkyl groups so that the total number of carbon atoms is 4 to 5, and it is most preferable to combine the alkyl groups. Specific examples of the group represented by the general formula (7-3a) include a tert-butyl group and a tert-pentyl group, and a tert-butyl group is more preferable.

Examples of the tertiary alkyl group-containing group that does not have a cyclic structure include the above-described branched tertiary alkyl group; the above-described branched tertiary alkyl group is a linear or branched alkylene group A tertiary alkyl group-containing chain alkyl group bonded to the above; a tertiary alkyloxycarbonyl group having the branched tertiary alkyl group described above as the tertiary alkyl group; And tertiary alkyloxycarbonylalkyl groups having a branched tertiary alkyl group.
The alkylene group in the tertiary alkyl group-containing chain alkyl group is preferably an alkylene group having 1 to 5 carbon atoms, more preferably an alkylene group having 1 to 4 carbon atoms, and still more preferably an alkylene group having 1 to 2 carbon atoms. .
As the chain-like tertiary alkyloxycarbonyl group, for example, a group represented by general formula (7-3b) shown below can be mentioned. ^R 21 ^{to R} in the formula (7-3b) ²³ are respectively similar to the formula (7-3a) in ^R 21 ^{to R 23.} The chain-like tertiary alkyloxycarbonyl group is preferably a tert-butyloxycarbonyl group (t-boc) or a tert-pentyloxycarbonyl group.
As the chain-like tertiary alkyloxycarbonylalkyl group, for example, a group represented by general formula (7-3c) shown below can be mentioned. ^R 21 ^{to R} in the formula (7-3c) ²³ are respectively similar to the formula (7-3a) in ^R 21 ^{to R 23.} f is an integer of 1 to 3, and 1 or 2 is preferable. As the chain-like tertiary alkyloxycarbonylalkyl group, a tert-butyloxycarbonylmethyl group, a tert-pentyloxycarbonylmethyl group, or a tert-butyloxycarbonylethyl group is preferable.

  Of these, the tertiary alkyl group-containing group having no cyclic structure is preferably a tertiary alkyloxycarbonyl group or a tertiary alkyloxycarbonylalkyl group, more preferably a tertiary alkyloxycarbonyl group. And tert-butyloxycarbonyl group (t-boc) is particularly preferable.

The tertiary alkyl group-containing group having a cyclic structure is a group having a tertiary carbon atom and a cyclic structure in the structure.
In the tertiary alkyl group-containing group having a cyclic structure, the cyclic structure preferably has 4 to 12 carbon atoms, more preferably 5 to 10 carbon atoms, and more preferably 6 to 10 carbon atoms constituting the ring. Most preferred. Examples of the cyclic structure include groups in which one or more hydrogen atoms have been removed from a polycycloalkane such as monocycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane. Preferable examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

Examples of the tertiary alkyl group-containing group having a cyclic structure include a group having the following group (1) or (2) as a tertiary alkyl group.
(1) A group in which a linear or branched alkyl group is bonded to a carbon atom constituting a ring of a cyclic alkyl group (cycloalkyl group), and the carbon atom is a tertiary carbon atom.
(2) A group in which an alkylene group having a tertiary carbon atom (branched alkylene group) is bonded to the carbon atom constituting the ring of the cycloalkyl group.

The linear or branched alkyl group in the group (1) preferably has 1 to 5 carbon atoms, more preferably 1 to 4 carbon atoms, and most preferably 1 to 3 carbon atoms. .
Specific examples of the group (1) include 2-methyl-2-adamantyl group, 2-ethyl-2-adamantyl group, 1-methyl-1-cycloalkyl group, 1-ethyl-1-cycloalkyl group and the like. More specifically, 1-methylcyclopentyl group, 1-ethylcyclopentyl group, 1-methylcyclohexyl group, 1-ethylcyclohexyl group, 2-methyl-2-adamantyl group, 2-ethyl-2-adamantyl group Etc.

In the group (2), the cycloalkyl group to which the branched alkylene group is bonded may have a substituent. Examples of the substituent include a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (= O).
Specific examples of the group (2) include groups represented by the following general formula (IV).

In the formula (IV), R ²⁴ is a cycloalkyl group which may or may not have a substituent. Examples of the substituent that the cycloalkyl group may have include a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (═O).
R ²⁵ and R ²⁶ are each independently a linear or branched alkyl group, and the alkyl group is the same as the alkyl group of R ^{21 to} R ²³ in the formula (7-3a). Can be mentioned.

  In the acid dissociable, dissolution inhibiting group-containing group (7-3), as the tertiary alkyl group-containing group, the general formula (7 A chain-like tertiary alkyloxycarbonyl group represented by -3b) is more preferred, and a tert-butyloxycarbonyl group (t-boc) is most preferred.

The component (A1) may include a structural unit (a8) that does not fall under any of the structural units (a1) to (a7).
The structural unit (a8) is not particularly limited as long as it is another structural unit that is not classified into the structural units (a1) to (a7) described above. Many known hitherto used as resist resins such as for excimer laser) can be used.

As the component (A1) used in the present invention, the following resins (A11) and resins (A12) are preferable. However, the present invention is not limited to these.
Resin (A11): a structural unit derived from hydroxystyrene (a5), a structural unit derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group (a1) and / or a structural unit derived from hydroxystyrene A resin having a structural unit (a7) in which at least one of the hydrogen atoms of the hydroxyl group contained in the structural unit is substituted with an acid dissociable, dissolution inhibiting group or an organic group containing an acid dissociable, dissolution inhibiting group.
Resin (A12): An acrylic resin having a structural unit (a1) derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group.
The resin (A11) is suitable for electron beams and EUV.
Resin (A12) is suitable for ArF excimer laser.

"Resin (A11)"
In the resin (A11), as the structural unit (a5), one type of structural unit may be used, or two or more types may be used in combination.
The proportion of the structural unit (a5) in the resin (A11) is preferably 50 to 90 mol%, and preferably 55 to 85 mol%, based on the total of all structural units constituting the resin (A11). More preferably, it is more preferably 60 to 80 mol%. When it is at least the lower limit of the range, moderate alkali solubility is obtained, and the effect of containing the structural unit (a5) is sufficiently obtained. When it is below the upper limit of the range, the balance with other structural units is good.

The resin (A11) may have only one of the structural units (a1) and (a7), or may have both. As the structural units (a1) and (a7), one type may be used alone, or two or more types may be used in combination.
When the resin (A11) has the structural unit (a1) and does not have the structural unit (a7), the proportion of the structural unit (a1) in the resin (A11) is all the structural units constituting the resin (A11). Is preferably 5 to 50 mol%, more preferably 10 to 40 mol%, still more preferably 15 to 35 mol%. When it is at least the lower limit of the range, a pattern can be obtained when it is a resist composition, and when it is at most the upper limit, the balance with other structural units is good.
When the resin (A11) has the structural unit (a7) and does not have the structural unit (a1), the proportion of the structural unit (a7) in the resin (A11) is the total structural unit constituting the resin (A11). Is preferably 5 to 50 mol%, more preferably 10 to 45 mol%, still more preferably 15 to 40 mol%. When it is at least the lower limit of the range, a pattern can be obtained when it is a resist composition, and when it is at most the upper limit, the balance with other structural units is good.

Moreover, resin (A11) may have structural units other than structural unit (a5), (a1), and (a7) arbitrarily.
Examples of the other structural unit include the structural unit (a6).
When the resin (A11) has the structural unit (a6), the proportion of the structural unit (a6) in the resin (A11) is 1 to 20 mol% with respect to the total of all the structural units constituting the resin (A11). Preferably, 3-15 mol% is more preferable, and 5-15 mol% is further more preferable. The effect by having a structural unit (a6) as it is more than the lower limit of this range is high, and the balance with another structural unit is favorable as it is below an upper limit.
Moreover, resin (A11) may have structural unit (a2)-(a4), (a8) etc. arbitrarily.

  In the present invention, preferred examples of the resin (A11) include, for example, a copolymer having the structural unit (a5) and the structural unit (a1), and a copolymer having the structural unit (a5) and the structural unit (a7). Etc. Examples of these copolymers include a copolymer composed of the structural unit (a5) and the structural unit (a1), a copolymer composed of the structural unit (a5) and the structural unit (a7), a structural unit (a5), and a structural unit. Examples thereof include a copolymer composed of (a1) and the structural unit (a6), a copolymer composed of the structural unit (a5), the structural unit (a1) and the structural unit (a7).

"Resin (A12)"
The “acrylic resin” is a resin that includes a structural unit derived from an acrylate ester such as the structural unit (a1) and does not include a styrenic structural unit such as the structural units (a5) to (a7). is there.
In the resin (A12), as the structural unit (a1), one type of structural unit may be used, or two or more types may be used in combination.
In the resin (A12), the proportion of the structural unit (a1) is preferably 10 to 80 mol%, more preferably 20 to 70 mol%, based on the total of all the structural units constituting the resin (A12). More preferred is mol%. By setting it to the lower limit value or more, a pattern can be easily obtained when the resist composition is used, and by setting it to the upper limit value or less, it is possible to balance with other structural units.

The resin (A12) preferably further has a structural unit (a2) in addition to the structural unit (a1).
In the resin (A12), as the structural unit (a2), one type of structural unit may be used alone, or two or more types may be used in combination.
The proportion of the structural unit (a2) in the resin (A12) is preferably 5 to 60 mol%, more preferably 10 to 50 mol%, with respect to the total of all structural units constituting the resin (A12). 50 mol% is more preferable. By setting it to the lower limit value or more, the effect of containing the structural unit (a2) is sufficiently obtained, and by setting the upper limit value or less, it is possible to balance with other structural units.

The resin (A12) preferably has a structural unit (a3) in addition to the structural unit (a1) or in addition to the structural unit (a1) and the structural unit (a2).
In the resin (A12), as the structural unit (a3), one type of structural unit may be used, or two or more types may be used in combination.
In the resin (A12), the proportion of the structural unit (a3) is preferably 5 to 50 mol%, more preferably 5 to 40 mol%, based on the total of all structural units constituting the resin (A12). 5 to 25 mol% is more preferable.

The resin (A12) may optionally have other structural units other than the structural units (a1) to (a3). Examples of the other structural unit include the structural unit (a4).
When the structural unit (a4) is contained in the resin (A12), the ratio is preferably 1 to 30 mol%, more preferably 10 to 20 mol%, based on the total of all the structural units constituting the resin (A12). preferable.

  In the present invention, the resin (A12) is preferably a copolymer having the structural units (a1), (a2) and (a3). Examples of such a copolymer include a copolymer composed of the structural units (a1), (a2) and (a3), and a copolymer composed of the structural units (a1), (a2), (a3) and (a4). A polymer etc. can be illustrated.

The mass average molecular weight (Mw) of the component (A1) (polystyrene conversion standard by gel permeation chromatography) is not particularly limited, but is preferably 1000 to 50000, more preferably 1500 to 30000, and 2500 to 20000. Most preferred. When it is smaller than the upper limit of this range, it has sufficient solubility in a resist solvent to be used as a resist, and when it is larger than the lower limit of this range, dry etching resistance and resist pattern cross-sectional shape are good.
Further, the dispersity (Mw / Mn) is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and most preferably 1.2 to 2.5. In addition, Mn shows a number average molecular weight.

The component (A1) can be obtained by polymerizing a monomer for deriving each structural unit by a known radical polymerization using a radical polymerization initiator such as azobisisobutyronitrile (AIBN).
Further, for the component (A1), in the polymerization, a chain transfer agent such as HS—CH ₂ —CH ₂ —CH ₂ —C (CF ₃ ) ₂ —OH is used in combination, so that the terminal A —C (CF ₃ ) ₂ —OH group may be introduced into the. As described above, a copolymer into which a hydroxyalkyl group in which a part of hydrogen atoms of an alkyl group is substituted with a fluorine atom is introduced has reduced development defects and LER (line edge roughness: uneven unevenness of line side walls). It is effective in reducing

[(A2) component]
The component (A2) is preferably a low molecular compound having a molecular weight of 500 or more and less than 4000 and having an acid dissociable, dissolution inhibiting group and a hydrophilic group as exemplified in the description of the component (A1). Specifically, a compound in which a part of hydrogen atoms of a hydroxyl group of a compound having a plurality of phenol skeletons is substituted with the acid dissociable, dissolution inhibiting group can be mentioned.
The component (A2) is, for example, a part of the hydrogen atom of the hydroxyl group of a low molecular weight phenol compound known as a sensitizer in a non-chemically amplified g-line or i-line resist or a heat resistance improver. Those substituted with a soluble dissolution inhibiting group are preferred and can be arbitrarily used.
Examples of such low molecular weight phenol compounds include bis (4-hydroxyphenyl) methane, bis (2,3,4-trihydroxyphenyl) methane, and bis (4-hydroxy-3-methylphenyl) -3,4-dihydroxy. Phenylmethane, bis (3-cyclohexyl-4-hydroxy-6-methylphenyl) -4-hydroxyphenylmethane, bis (3-cyclohexyl-4-hydroxy-6-methylphenyl) -3,4-dihydroxyphenylmethane, 1 -[1- (4-hydroxyphenyl) isopropyl] -4- [1,1-bis (4-hydroxyphenyl) ethyl] benzene, bis (2,3, -trihydroxyphenyl) methane, bis (2,4- Dihydroxyphenyl) methane, 2,3,4-trihydroxyphenyl-4′-hydroxy Siphenylmethane, 2- (2,3,4-trihydroxyphenyl) -2- (2 ′, 3 ′, 4′-trihydroxyphenyl) propane, 2- (2,4-dihydroxyphenyl) -2- ( 2 ', 4'-dihydroxyphenyl) propane, 2- (4-hydroxyphenyl) -2- (4'-hydroxyphenyl) propane, 2- (3-fluoro-4-hydroxyphenyl) -2- (3'- Fluoro-4'-hydroxyphenyl) propane, 2- (2,4-dihydroxyphenyl) -2- (4'-hydroxyphenyl) propane, 2- (2,3,4-trihydroxyphenyl) -2- (4 Bisphenol-type conversion such as '-hydroxyphenyl) propane and 2- (2,3,4-trihydroxyphenyl) -2- (4'-hydroxy-3', 5'-dimethylphenyl) propane Compound: Tris (4-hydroxyphenyl) methane, bis (4-hydroxy-3-methylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-2,3,5-trimethylphenyl) -2-hydroxy Phenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -4-hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -3-hydroxyphenylmethane, bis (4-hydroxy-3) , 5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -4-hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -3-hydroxy Phenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -2-hydro Siphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -3,4-dihydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -3,4-dihydroxyphenylmethane, bis ( 4-hydroxy-2,5-dimethylphenyl) -2,4-dihydroxyphenylmethane, bis (4-hydroxyphenyl) -3-methoxy-4-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-2-) Methylphenyl) -4-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -3-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -2- Hydroxyphenylmethane and bis (5-cyclohexyl- Trisphenol type compounds such as -hydroxy-2-methylphenyl) -3,4-dihydroxyphenylmethane; 2,4-bis (3,5-dimethyl-4-hydroxybenzyl) -5-hydroxyphenol, and 2,6 -Linear trinuclear phenol compounds such as bis (2,5-dimethyl-4-hydroxybenzyl) -4-methylphenol; 1,1-bis [3- (2-hydroxy-5-methylbenzyl) -4- Hydroxy-5-cyclohexylphenyl] isopropane, bis [2,5-dimethyl-3- (4-hydroxy-5-methylbenzyl) -4-hydroxyphenyl] methane, bis [2,5-dimethyl-3- (4) -Hydroxybenzyl) -4-hydroxyphenyl] methane, bis [3- (3,5-dimethyl-4-hydroxybenzyl) -4- Hydroxy-5-methylphenyl] methane, bis [3- (3,5-dimethyl-4-hydroxybenzyl) -4-hydroxy-5-ethylphenyl] methane, bis [3- (3,5-diethyl-4-) Hydroxybenzyl) -4-hydroxy-5-methylphenyl] methane, bis [3- (3,5-diethyl-4-hydroxybenzyl) -4-hydroxy-5-ethylphenyl] methane, bis [2-hydroxy-3 -(3,5-dimethyl-4-hydroxybenzyl) -5-methylphenyl] methane, bis [2-hydroxy-3- (2-hydroxy-5-methylbenzyl) -5-methylphenyl] methane, bis [4 -Hydroxy-3- (2-hydroxy-5-methylbenzyl) -5-methylphenyl] methane and bis [2,5-dimethyl-3- (2- Linear type tetranuclear phenol compounds such as droxy-5-methylbenzyl) -4-hydroxyphenyl] methane; 2,4-bis [2-hydroxy-3- (4-hydroxybenzyl) -5-methylbenzyl] -6 -Cyclohexylphenol, 2,4-bis [4-hydroxy-3- (4-hydroxybenzyl) -5-methylbenzyl] -6-cyclohexylphenol, and 2,6-bis [2,5-dimethyl-3- ( 2-hydroxy-5-methylbenzyl) -4-hydroxybenzyl] -4-polyphenols such as linear polyphenol compounds such as 5-nuclear phenol compounds; 1- [1- (4-hydroxyphenyl) isopropyl]- 4- [1,1-bis (4-hydroxyphenyl) ethyl] benzene, and 1- [1- (3-methyl-4) Polynuclear branched compounds such as hydroxyphenyl) isopropyl] -4- [1,1-bis (3-methyl-4-hydroxyphenyl) ethyl] benzene; phenols such as phenol, m-cresol, p-cresol or xylenol Examples thereof include 2-12 nuclei of formalin condensate. Of course, it is not limited to these.
The acid dissociable, dissolution inhibiting group is not particularly limited, and examples thereof include those described above.

(A) A component may be used individually by 1 type and may use 2 or more types together.
In the present invention, the component (A) preferably contains the component (A1) because the lithography properties are improved.

<(B) component>
The component (B) is not particularly limited, and those that have been proposed as acid generators for chemically amplified resists can be used. Examples of such acid generators include onium salt acid generators such as iodonium salts and sulfonium salts, oxime sulfonate acid generators, bisalkyl or bisarylsulfonyldiazomethanes, and poly (bissulfonyl) diazomethanes. There are various known diazomethane acid generators, nitrobenzyl sulfonate acid generators, imino sulfonate acid generators, disulfone acid generators, and the like.

  As the onium salt acid generator, for example, a compound represented by the following general formula (b-1) or (b-2) can be used.

［式中、Ｒ^１”〜Ｒ^３”，Ｒ^５”〜Ｒ^６”は、それぞれ独立に、置換基を有していてもよいアリール基またはアルキル基を表し；式（ｂ−１）におけるＲ^１”〜Ｒ^３”のうち、いずれか２つが相互に結合して式中のイオウ原子と共に環を形成してもよく；Ｒ^４”は、置換基を有していても良いアルキル基、ハロゲン化アルキル基、アリール基、またはアルケニル基を表し；Ｒ^１”〜Ｒ^３”のうち少なくとも１つはアリール基を表し、Ｒ^５”〜Ｒ^６”のうち少なくとも１つはアリール基を表す。］

[Wherein, R ¹ ″ to R ³ ″ and R ⁵ ″ to R ⁶ ″ each independently represents an aryl group or an alkyl group which may have a substituent; R in the formula (b-1) Any one of ¹ ″ to R ³ ″ may be bonded to each other to form a ring together with the sulfur atom in the formula; R ⁴ ″ represents an alkyl group which may have a substituent, a halogen atom; An alkyl group, an aryl group, or an alkenyl group; at least one of R ¹ ″ to R ³ ″ represents an aryl group, and at least one of R ⁵ ″ to R ⁶ ″ represents an aryl group.]

In formula (b-1), R ¹ ″ to R ³ ″ each independently represents an aryl group or an alkyl group which may have a substituent. In addition, any two of R ¹ ″ to R ³ ″ in formula (b-1) may be bonded to each other to form a ring together with the sulfur atom in the formula.
Further, at least one of R ¹ ″ to R ³ ″ represents an aryl group. Of R ¹ ″ to R ³ ″, two or more are preferably aryl groups, and most preferably all of R ¹ ″ to R ³ ″ are aryl groups.

The aryl group for R ¹ ″ to R ³ ″ is not particularly limited, and examples thereof include an aryl group having 6 to 20 carbon atoms. The aryl group is preferably an aryl group having 6 to 10 carbon atoms because it can be synthesized at a low cost. Specific examples include a phenyl group and a naphthyl group.
The aryl group may have a substituent. “Having a substituent” means that part or all of the hydrogen atoms of the aryl group are substituted with a substituent, and examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a hydroxyl group, An alkoxyalkyloxy group, —O—R ⁵⁰ —CO—O—R ^{51 wherein} R ⁵⁰ is an alkylene group and R ⁵¹ is an acid-dissociable group; ] Etc. are mentioned.
The alkyl group that may be substituted for the hydrogen atom of the aryl group is preferably an alkyl group having 1 to 5 carbon atoms, and is a methyl group, ethyl group, propyl group, n-butyl group, or tert-butyl group. Is most preferred.
As the alkoxy group that may be substituted for the hydrogen atom of the aryl group, an alkoxy group having 1 to 5 carbon atoms is preferable, and a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, A tert-butoxy group is preferable, and a methoxy group and an ethoxy group are most preferable.
The halogen atom that may be substituted with the hydrogen atom of the aryl group is preferably a fluorine atom.

Examples of the alkoxyalkyloxy group in which the hydrogen atom of the aryl group may be substituted include, for example, —O—C (R ⁴⁷ ) (R ⁴⁸ ) —O—R ^{49 wherein} R ⁴⁷ and R ⁴⁸ are each It is independently a hydrogen atom or a linear or branched alkyl group, R ⁴⁹ is an alkyl group, and R ⁴⁸ and R ⁴⁹ may be bonded to each other to form one ring structure. Provided ^that at least one of ^{R 47} and ^{R 48} are hydrogen atoms. ].
In R ⁴⁷ and R ⁴⁸ , the alkyl group preferably has 1 to 5 carbon atoms, preferably an ethyl group or a methyl group, and most preferably a methyl group.
One of R ⁴⁷ and R ⁴⁸ is preferably a hydrogen atom, the other is preferably a hydrogen atom or a methyl group, and both R ⁴⁷ and R ⁴⁸ are particularly preferably hydrogen atoms.
The alkyl group for R ⁴⁹ preferably has 1 to 15 carbon atoms and may be linear, branched or cyclic.
The linear or branched alkyl group for R ⁴⁹ preferably has 1 to 5 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, an n-butyl group, and a tert-butyl group. Can be mentioned.
The cyclic alkyl group for R ⁴⁹ preferably has 4 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms.
Specifically, monocycloalkane, bicycloalkane, tricycloalkane, tetracycloalkane, etc., which may or may not be substituted with an alkyl group having 1 to 5 carbon atoms, a fluorine atom or a fluorinated alkyl group, etc. And a group obtained by removing one or more hydrogen atoms from the polycycloalkane. Examples of the monocycloalkane include cyclopentane and cyclohexane. Examples of the polycycloalkane include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among them, a group obtained by removing one or more hydrogen atoms from adamantane is preferable.
R ⁴⁸ and R ⁴⁹ may be bonded to each other to form one ring structure. In this case, the R ⁴⁸ and R ^49, the oxygen atom having R ⁴⁹ is bonded, a cyclic group is formed by the carbon atom having the oxygen atom and R ⁴⁸ are bonded. The cyclic group is preferably a 4-7 membered ring, and more preferably a 4-6 membered ring.

In —O—R ⁵⁰ —CO—O—R ⁵¹ in which the hydrogen atom of the aryl group may be substituted, the alkylene group in R ⁵⁰ is preferably a linear or branched alkylene group, and the carbon number thereof Is preferably 1-5. Examples of the alkylene group include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, and a 1,1-dimethylethylene group.
The acid dissociable group in R ⁵¹ is not particularly limited as long as it is an organic group that can be dissociated by the action of an acid (acid generated from the component (B) at the time of exposure). Examples include the same acid dissociable, dissolution inhibiting groups. Among them, the tertiary alkyl ester type is preferable.

The alkyl group for R 1 ^{"~R 3",} is not particularly limited, for example, linear C1-10, branched or cyclic alkyl group, and the like. It is preferable that it is C1-C5 from the point which is excellent in resolution. Specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-pentyl group, a cyclopentyl group, a hexyl group, a cyclohexyl group, a nonyl group, and a decyl group. A methyl group is preferable because it is excellent in resolution and can be synthesized at low cost.
The alkyl group may have a substituent. “Having a substituent” means that part or all of the hydrogen atoms of the alkyl group are substituted with a substituent, and the substituent may be a substituent that the aryl group may have. The thing similar to what was mentioned as a group is mentioned.

When any two of R ¹ ″ to R ³ ″ in formula (b-1) are bonded to each other to form a ring together with the sulfur atom in the formula, a 3 to 10 membered ring including the sulfur atom is formed. It is preferable that a 5- to 7-membered ring is formed.
When any two of R ¹ ″ to R ³ ″ in formula (b-1) are bonded to each other to form a ring together with the sulfur atom in the formula, the remaining one may be an aryl group preferable. Examples of the aryl group are the same as the aryl groups of R ¹ ″ to R ³ ″.

Of the cation moieties of the compound represented by formula (b-1), when R ¹ ″ to R ³ ″ are all phenyl groups that may have a substituent, that is, the cation moiety is triphenylmethane. Specific examples of preferred skeletons include cation moieties represented by the following formulas (I-1-1) to (I-1-8).
Moreover, what substituted a part or all of the phenyl group in these cation parts with the naphthyl group which may have a substituent is mentioned as a preferable thing. Of the three phenyl groups, 1 or 2 is preferably substituted with the naphthyl group.

Moreover, among the cation moieties of the compound represented by the formula (b-1), any two of R ¹ ″ to R ³ ″ are bonded to each other to form a ring together with the sulfur atom in the formula. Preferable specific examples of the case include, for example, cation moieties represented by the following formulas (I-1-10) to (I-1-11).
In the following formula (I-1-10), R ⁹ is a phenyl group, a naphthyl group, or an alkyl group having 1 to 5 carbon atoms which may have a substituent.
In the following formula (I-1-11), R ¹⁰ represents a phenyl group, a naphthyl group, an alkyl group having 1 to 5 carbon atoms, an alkoxy group, or a hydroxyl group, which may have a substituent.
u is an integer of 1 to 3, and 1 or 2 is most preferable.

［式中、Ｒ^９は、置換基を有していてもよいフェニル基、ナフチル基または炭素数１〜５のアルキル基であり、Ｒ^１０は、置換基を有していてもよいフェニル基、ナフチル基、炭素数１〜５のアルキル基、アルコキシ基または水酸基であり、ｕは１〜３の整数である。］

[Wherein, R ⁹ is a phenyl group optionally having a substituent, a naphthyl group or an alkyl group having 1 to 5 carbon atoms, and R ¹⁰ is a phenyl group optionally having a substituent, A naphthyl group, an alkyl group having 1 to 5 carbon atoms, an alkoxy group or a hydroxyl group, and u is an integer of 1 to 3; ]

R 4 ^"is an optionally substituted alkyl group, a halogenated alkyl group, an aryl group or an alkenyl group.
The alkyl group for R ⁴ ″ may be linear, branched or cyclic.
The linear or branched alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 4 carbon atoms.
The cyclic alkyl group preferably has 4 to 15 carbon atoms, more preferably 4 to 10 carbon atoms, and most preferably 6 to 10 carbon atoms.
Examples of the halogenated alkyl group for R ⁴ ″ include groups in which part or all of the hydrogen atoms of the linear, branched, or cyclic alkyl group have been substituted with halogen atoms. A fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, A fluorine atom is preferable.
In the halogenated alkyl group, the ratio of the number of halogen atoms to the total number of halogen atoms and hydrogen atoms contained in the halogenated alkyl group (halogenation rate (%)) is preferably 10 to 100%. 50 to 100% is preferable, and 100% is most preferable. The higher the halogenation rate, the better the acid strength.
The aryl group for R ⁴ ″ is preferably an aryl group having 6 to 20 carbon atoms.
The alkenyl group in R ⁴ ″ is preferably an alkenyl group having 2 to 10 carbon atoms.
In the above R ⁴ ″, “optionally substituted” means one of hydrogen atoms in the linear, branched or cyclic alkyl group, halogenated alkyl group, aryl group, or alkenyl group. It means that part or all may be substituted with a substituent (an atom or group other than a hydrogen atom).
The number of substituents in R ⁴ ″ may be one or two or more.

Examples of the substituent include a halogen atom, a hetero atom, an alkyl group, and a formula: XQ ^1- [wherein Q ¹ is a divalent linking group containing an oxygen atom, and X has a substituent. And a hydrocarbon group having 3 to 30 carbon atoms. ] Etc. which are represented by these.
Examples of the halogen atom and alkyl group include the same groups as those described above for R ⁴ ″ as the halogen atom and alkyl group in the halogenated alkyl group.
Examples of the hetero atom include an oxygen atom, a nitrogen atom, and a sulfur atom.

X-Q 1 ^- In the group represented by, Q ¹ represents a divalent linking group containing an oxygen atom.
Q ¹ may contain an atom other than an oxygen atom. Examples of atoms other than oxygen atoms include carbon atoms, hydrogen atoms, oxygen atoms, sulfur atoms, and nitrogen atoms.
Examples of the divalent linking group containing an oxygen atom include an oxygen atom (ether bond; —O—), an ester bond (—C (═O) —O—), and an amide bond (—C (═O) —NH. -), A carbonyl group (-C (= O)-), a non-hydrocarbon oxygen atom-containing linking group such as a carbonate bond (-O-C (= O) -O-); the non-hydrocarbon oxygen atom Examples include a combination of a containing linking group and an alkylene group.
Examples of the combination include —R ⁹¹ —O—, —R ⁹² —O—C (═O) —, —C (═O) —O—R ⁹³ —, —C (═O) —O—R. ⁹³ —O—C (═O) — (wherein R ^{91 to} R ⁹³ are each independently an alkylene group).
The alkylene group for R ^{91 to} R ⁹³ is preferably a linear or branched alkylene group, and the alkylene group preferably has 1 to 12 carbon atoms, more preferably 1 to 5 carbon atoms, and particularly preferably 1 to 3 carbon atoms. preferable.
Specific examples of the alkylene group include a methylene group [—CH ₂ —]; —CH (CH ₃ ) —, —CH (CH ₂ CH ₃ ) —, —C (CH ₃ ) ₂ —, —C ( _{CH 3) (CH 2 CH 3} ) -, - C (CH 3) (CH 2 CH 2 CH 3) -, - C (CH 2 CH 3) 2 - ; alkylethylene groups such as ethylene group _[-CH 2 CH _2— ]; —CH (CH ₃ ) CH ₂ —, —CH (CH ₃ ) CH (CH ₃ ) —, —C (CH ₃ ) ₂ CH ₂ —, —CH (CH ₂ CH ₃ ) CH ₂ —, Alkylethylene groups such as —CH (CH ₂ CH ₃ ) CH ₂ —; trimethylene group (n-propylene group) [—CH ₂ CH ₂ CH ₂ —]; —CH (CH ₃ ) CH ₂ CH ₂ —, —CH _{2 CH (CH 3) CH 2} - alkyl trimethylene group and the like; Toramechiren group _{[-CH 2 CH 2 CH 2 CH} 2 -]; - CH (CH 3) CH 2 CH 2 CH 2 -, - CH 2 CH (CH 3) CH 2 CH 2 - alkyl tetramethylene group and the like; penta And methylene group [—CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ —] and the like.
Q ¹ is preferably a divalent linking group containing an ester bond or an ether bond. Among them, —R ⁹¹ —O—, —R ⁹² —O—C (═O) —, —C (═O) — O—, —C (═O) —O—R ⁹³ — or —C (═O) —O—R ⁹³ —O—C (═O) — is preferred.

In the group represented by XQ ^1- , the hydrocarbon group of X may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group.
The aromatic hydrocarbon group is a hydrocarbon group having an aromatic ring. The aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30, more preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 12. However, the carbon number does not include the carbon number in the substituent.
Specific examples of the aromatic hydrocarbon group include a hydrogen atom from an aromatic hydrocarbon ring such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, and a phenanthryl group. Examples include aryl groups such as aryl group, benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, etc., from which one is removed. The number of carbon atoms of the alkyl chain in the arylalkyl group is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.
The aromatic hydrocarbon group may have a substituent. For example, a part of carbon atoms constituting the aromatic ring of the aromatic hydrocarbon group may be substituted with a hetero atom, and the hydrogen atom bonded to the aromatic ring of the aromatic hydrocarbon group is substituted with the substituent. May be.
Examples of the former include heteroaryl groups in which some of the carbon atoms constituting the ring of the aryl group are substituted with heteroatoms such as oxygen atoms, sulfur atoms and nitrogen atoms, and aromatic hydrocarbons in the arylalkyl groups Examples include heteroarylalkyl groups in which some of the carbon atoms constituting the ring are substituted with the above heteroatoms.
Examples of the substituent of the aromatic hydrocarbon group in the latter example include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and an oxygen atom (═O).
The alkyl group as a substituent of the aromatic hydrocarbon group is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. preferable.
The alkoxy group as a substituent of the aromatic hydrocarbon group is preferably an alkoxy group having 1 to 5 carbon atoms, and is a methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, n-butoxy group, tert- A butoxy group is preferable, and a methoxy group and an ethoxy group are most preferable.
Examples of the halogen atom as a substituent for the aromatic hydrocarbon group include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
Examples of the halogenated alkyl group as the substituent of the aromatic hydrocarbon group include groups in which part or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms.

The aliphatic hydrocarbon group for X may be a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group. The aliphatic hydrocarbon group may be linear, branched or cyclic.
In X, the aliphatic hydrocarbon group may have a part of the carbon atoms constituting the aliphatic hydrocarbon group substituted by a substituent containing a hetero atom, and the hydrogen atom constituting the aliphatic hydrocarbon group May be substituted with a substituent containing a hetero atom.
The “heteroatom” in X is not particularly limited as long as it is an atom other than a carbon atom and a hydrogen atom, and examples thereof include a halogen atom, an oxygen atom, a sulfur atom, and a nitrogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, an iodine atom, and a bromine atom.
The substituent containing a hetero atom may be composed only of the hetero atom, or may be a group containing a group or atom other than the hetero atom.
Specific examples of the substituent for substituting a part of carbon atoms include, for example, —O—, —C (═O) —O—, —C (═O) —, —O—C (═O) —O. -, - C (= O) -NH -, - NH- (H is an alkyl group, may be substituted with a substituent such as an acyl group), - S -, - S (= O) 2 -, - S (= O) ₂ —O— and the like can be mentioned. When the aliphatic hydrocarbon group is cyclic, these substituents may be included in the ring structure.
Specific examples of the substituent that substitutes part or all of the hydrogen atoms include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, an oxygen atom (═O), and a cyano group.
The alkoxy group is preferably an alkoxy group having 1 to 5 carbon atoms, preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group, and a methoxy group or an ethoxy group. Is most preferred.
As said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, A fluorine atom is preferable.
As the halogenated alkyl group, a part or all of hydrogen atoms of an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, a tert-butyl group, etc. And a group substituted with a halogen atom.

Examples of the aliphatic hydrocarbon group include a linear or branched saturated hydrocarbon group, a linear or branched monovalent unsaturated hydrocarbon group, or a cyclic aliphatic hydrocarbon group (aliphatic ring). Formula group) is preferred.
The linear saturated hydrocarbon group (alkyl group) preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 10 carbon atoms. Specifically, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, isotridecyl group, tetradecyl group Group, pentadecyl group, hexadecyl group, isohexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, heicosyl group, docosyl group and the like.
The branched saturated hydrocarbon group (alkyl group) preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10 carbon atoms. Specifically, for example, 1-methylethyl group, 1-methylpropyl group, 2-methylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1-ethylbutyl group, 2-ethylbutyl group, Examples include 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group and the like.

As an unsaturated hydrocarbon group, it is preferable that carbon number is 2-10, 2-5 are preferable, 2-4 are preferable, and 3 is especially preferable. Examples of the linear monovalent unsaturated hydrocarbon group include a vinyl group, a propenyl group (allyl group), and a butynyl group. Examples of the branched monovalent unsaturated hydrocarbon group include a 1-methylpropenyl group and a 2-methylpropenyl group.
Among the above, the unsaturated hydrocarbon group is particularly preferably a propenyl group.

The aliphatic cyclic group may be a monocyclic group or a polycyclic group. The number of carbon atoms is preferably 3 to 30, more preferably 5 to 30, further preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 12.
Specifically, for example, a group in which one or more hydrogen atoms have been removed from a monocycloalkane; a group in which one or more hydrogen atoms have been removed from a polycycloalkane such as bicycloalkane, tricycloalkane, tetracycloalkane, etc. Can be mentioned. More specifically, a group in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane; one or more polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Examples include a group excluding a hydrogen atom.
When the aliphatic cyclic group does not contain a substituent containing a hetero atom in the ring structure, the aliphatic cyclic group is preferably a polycyclic group, and one or more hydrogen atoms from the polycycloalkane are substituted. Excluded groups are preferred, and groups obtained by removing one or more hydrogen atoms from adamantane are most preferred.
When the aliphatic cyclic group includes a substituent containing a hetero atom in the ring structure, examples of the substituent containing a hetero atom include —O—, —C (═O) —O—, —S—. , —S (═O) ₂ — and —S (═O) ₂ —O— are preferable. Specific examples of the aliphatic cyclic group include the following formulas (L1) to (L5), (S1) to (S4), and the like.

［式中、Ｑ”は炭素数１〜５のアルキレン基、−Ｏ−、−Ｓ−、−Ｏ−Ｒ^９４−または−Ｓ−Ｒ^９５−であり、Ｒ^９４およびＲ^９５はそれぞれ独立に炭素数１〜５のアルキレン基であり、ｍは０または１の整数である。］

[Wherein, Q ″ is an alkylene group having 1 to 5 carbon atoms, —O—, —S—, —O—R ⁹⁴ — or —S—R ⁹⁵ —, wherein R ⁹⁴ and R ⁹⁵ are each independently carbon. An alkylene group of 1 to 5 and m is an integer of 0 or 1.]

In the formula, examples of the alkylene group for Q ″, R ⁹⁴ and R ⁹⁵ include the same alkylene groups as those described above for R ^{91 to} R ⁹³ .
In these aliphatic cyclic groups, a part of hydrogen atoms bonded to carbon atoms constituting the ring structure may be substituted with a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and an oxygen atom (═O).
The alkyl group is preferably an alkyl group having 1 to 5 carbon atoms, particularly preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group.
Examples of the alkoxy group and the halogen atom are the same as those exemplified as the substituent for substituting part or all of the hydrogen atoms.

In the present invention, X is preferably a cyclic group which may have a substituent. The cyclic group may be an aromatic hydrocarbon group which may have a substituent, an aliphatic cyclic group which may have a substituent, or a substituent. It is preferably an aliphatic cyclic group that may be used.
The aromatic hydrocarbon group is preferably a naphthyl group which may have a substituent or a phenyl group which may have a substituent.
As the aliphatic cyclic group which may have a substituent, a polycyclic aliphatic cyclic group which may have a substituent is preferable. The polycyclic aliphatic cyclic group is preferably a group obtained by removing one or more hydrogen atoms from the polycycloalkane, the above (L2) to (L5), (S3) to (S4), and the like.

In the present invention, ^{R 4} ", ^{X-Q 1} - as a substituent preferably has the case, ^{R 4."} The, ^{X-Q 1} -Y 1 - in the Formula, ^{Q 1} and X are the Y ¹ is an optionally substituted alkylene group having 1 to 4 carbon atoms or an optionally substituted fluorinated alkylene group having 1 to 4 carbon atoms. ] Is preferable.
In the group represented by XQ ¹ -Y ^1- , the alkylene group for Y ¹ includes the same alkylene groups as those described above for Q ¹ having 1 to 4 carbon atoms.
Examples of the fluorinated alkylene group include groups in which part or all of the hydrogen atoms of the alkylene group have been substituted with fluorine atoms.
As Y ^1, _{specifically, -CF 2 -, - CF 2} CF 2 -, - CF 2 CF 2 CF 2 -, - CF (CF 3) CF 2 -, - CF (CF 2 CF 3) -, _{-C (CF 3) 2 -,} - CF 2 CF 2 CF 2 CF 2 -, - CF (CF 3) CF 2 CF 2 -, - CF 2 CF (CF 3) CF 2 -, - CF (CF 3) CF (CF ₃ ) —, —C (CF ₃ ) ₂ CF ₂ —, —CF (CF ₂ CF ₃ ) CF ₂ —, —CF (CF ₂ CF ₂ CF ₃ ) —, —C (CF ₃ ) (CF _{2 CF 3) -; - CHF} -, - CH 2 CF 2 -, - CH 2 CH 2 CF 2 -, - CH 2 CF 2 CF 2 -, - CH (CF 3) CH 2 -, - CH (CF 2 _{CF 3) -, - C (} CH 3) (CF 3) -, - CH 2 CH 2 CH 2 CF 2 -, - C H ₂ CH ₂ CF ₂ CF ₂ —, —CH (CF ₃ ) CH ₂ CH ₂ —, —CH ₂ CH (CF ₃ ) CH ₂ —, —CH (CF ₃ ) CH (CF ₃ ) —, —C ( _{CF 3) 2 CH 2 -;} - CH 2 -, - CH 2 CH 2 -, - CH 2 CH 2 CH 2 -, - CH (CH 3) CH 2 -, - CH (CH 2 CH 3) -, - _{C (CH 3) 2 -,} - CH 2 CH 2 CH 2 CH 2 -, - CH (CH 3) CH 2 CH 2 -, - CH 2 CH (CH 3) CH 2 -, - CH (CH 3) CH _{(CH 3) -, - C} (CH 3) 2 CH 2 -, - CH (CH 2 CH 3) CH 2 -, - CH (CH 2 CH 2 CH 3) -, - C (CH 3) (CH 2 CH ₃ ) — and the like.

Y ¹ is preferably a fluorinated alkylene group, and particularly preferably a fluorinated alkylene group in which the carbon atom bonded to the adjacent sulfur atom is fluorinated. Examples of such fluorinated alkylene _{group, -CF 2 -, - CF 2} CF 2 -, - CF 2 CF 2 CF 2 -, - CF (CF 3) CF 2 -, - CF 2 CF 2 CF 2 CF 2 _{-, - CF (CF 3)} CF 2 CF 2 -, - CF 2 CF (CF 3) CF 2 -, - CF (CF 3) CF (CF 3) -, - C (CF 3) 2 CF 2 -, _{-CF (CF 2 CF 3) CF} 2 -; - CH 2 CF 2 -, - CH 2 CH 2 CF 2 -, - CH 2 CF 2 CF 2 -; - CH 2 CH 2 CH 2 CF 2 -, - CH ₂ CH ₂ CF ₂ CF ₂ —, —CH ₂ CF ₂ CF ₂ CF ₂ — and the like can be mentioned.
Of _{these, -CF 2 -, - CF 2} CF 2 -, - CF 2 CF 2 CF 2 -, or _CH 2 _CF 2 CF ₂ - is _{preferable, -CF 2 -, - CF 2} CF 2 - or -CF ₂ CF ₂ CF ₂ - is more preferable, -CF ₂ - is particularly preferred.

The alkylene group or fluorinated alkylene group may have a substituent. An alkylene group or a fluorinated alkylene group has a “substituent” means that part or all of the hydrogen atom or fluorine atom in the alkylene group or fluorinated alkylene group is substituted with an atom or group other than a hydrogen atom and a fluorine atom. Means that
Examples of the substituent that the alkylene group or fluorinated alkylene group may have include an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a hydroxyl group.

In formula (b-2), R ⁵ ″ to R ⁶ ″ each independently represents an aryl group or an alkyl group. At least one of R ⁵ ″ to R ⁶ ″ represents an aryl group. It is preferable that all of R ⁵ ″ to R ⁶ ″ are aryl groups.
As the aryl group for R ⁵ ″ to R ⁶ ″, the same as the aryl groups for R ¹ ″ to R ³ ″ can be used.
Examples of the alkyl group for R ⁵ ″ to R ⁶ ″ include the same as the alkyl group for R ¹ ″ to R ³ ″.
Among these, it is most preferable that all of R ⁵ ″ to R ⁶ ″ are phenyl groups.
"As ^{R 4} in the formula (b-1)" ^{R 4} in the In the formula (b-2) include the same as.

Specific examples of the onium salt acid generators represented by formulas (b-1) and (b-2) include diphenyliodonium trifluoromethanesulfonate or nonafluorobutanesulfonate; bis (4-tert-butylphenyl) iodonium. Trifluoromethane sulfonate or nonafluorobutane sulfonate; triphenylsulfonium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; tri (4-methylphenyl) sulfonium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its Nonafluorobutanesulfonate; dimethyl (4-hydroxynaphthyl) sulfonium trifluoromethanesulfonate, its heptaful Lopropane sulfonate or its nonafluorobutane sulfonate; trifluoromethane sulfonate of monophenyldimethylsulfonium, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; trifluoromethane sulfonate of diphenyl monomethylsulfonium, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate (4-methylphenyl) diphenylsulfonium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; (4-methoxyphenyl) diphenylsulfonium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; Trifluoromethanesulfonate of tri (4-tert-butyl) phenylsulfonium, its heptafluoropropane sulfonate or its nonafluorobutanesulfonate; trifluoromethanesulfonate of diphenyl (1- (4-methoxy) naphthyl) sulfonium, its heptafluoropropane Sulfonate or its nonafluorobutane sulfonate; trifluoromethane sulfonate of di (1-naphthyl) phenylsulfonium, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1-phenyltetrahydrothiophenium trifluoromethane sulfonate, its heptafluoropropane sulfonate Or nonafluorobutanesulfonate thereof; 1- (4-methylphenyl) ) Tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropane sulfonate 1- (4-methoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate; 1- (4-ethoxynaphthalene-1- Yl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonaflu 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate; 1-phenyltetrahydrothiopyranium trifluoromethanesulfonate , Its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- (4-hydroxyphenyl) tetrahydrothiopyranium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- (3,5-dimethyl -4-Hydroxyphenyl) tetrahydrothiopyranium trifluoromethanesulfonate, its heptafluoropropanes Honeto or nonafluorobutanesulfonate; 1- (4-methylphenyl) trifluoromethanesulfonate tetrahydrothiophenium Pila chloride, heptafluoropropane sulfonate or its nonafluorobutane sulfonate, and the like.
In addition, the anion part of these onium salts is methanesulfonate, n-propanesulfonate, n-butanesulfonate, n-octanesulfonate, 1-adamantanesulfonate, 2-norbornanesulfonate, d-camphor-10-sulfonate, benzenesulfonate, Onium salts substituted with alkyl sulfonates such as fluorobenzene sulfonate and p-toluene sulfonate can also be used.
Moreover, the onium salt which replaced the anion part of these onium salts by the anion part represented by either of following formula (b1)-(b8) can also be used.

［式中、ｐは１〜３の整数であり、ｖ０は０〜３の整数であり、ｑ１〜ｑ２はそれぞれ独立に１〜５の整数であり、ｑ３は１〜１２の整数であり、ｒ１〜ｒ２はそれぞれ独立に０〜３の整数であり、ｇは１〜２０の整数であり、ｔ３は１〜３の整数であり、Ｒ^７は置換基である。］

[Wherein, p is an integer of 1 to 3, v0 is an integer of 0 to 3, q1 to q2 are each independently an integer of 1 to 5, q3 is an integer of 1 to 12, and r1 ~r2 are each independently an integer of 0 to 3, g is an integer of 1 to 20, t3 is an integer from 1 to 3, ^{R 7} is a substituent. ]

［式中、ｐ、Ｒ^７、Ｑ”はそれぞれ前記と同じであり、ｎ１〜ｎ５はそれぞれ独立に０または１であり、ｖ１〜ｖ５はそれぞれ独立に０〜３の整数であり、ｗ１〜ｗ５はそれぞれ独立に０〜３の整数である。］

[Wherein, p, R ⁷ and Q ″ are the same as defined above, n1 to n5 are each independently 0 or 1, v1 to v5 are each independently an integer of 0 to 3, w1 to w5 Are each independently an integer of 0 to 3.]

Examples of the substituent for R ⁷ are the same as those described above as the substituent that the aliphatic hydrocarbon group may have and the substituent that the aromatic hydrocarbon group may have in X. Can be mentioned.
Code (r1 and r2, w1 to w5) attached to R ⁷ when is an integer of 2 or more, a plurality of the ^{R 7} groups may be the same, respectively, may be different.
r1 to r2 and w1 to w5 are each preferably an integer of 0 to 2, and more preferably 0 or 1.
v0 to v5 are preferably 0 to 2, and most preferably 0 or 1.
t3 is preferably 1 or 2, and most preferably 1.
q3 is preferably 1 to 5, more preferably 1 to 3, and most preferably 1.

  Moreover, as an onium salt type | system | group acid generator, in the said general formula (b-1) or (b-2), an anion part is represented by the following general formula (b-3) or (b-4). An onium salt-based acid generator replaced with can also be used (the cation moiety is the same as (b-1) or (b-2)).

［式中、Ｘ”は、少なくとも１つの水素原子がフッ素原子で置換された炭素数２〜６のアルキレン基を表し；Ｙ”、Ｚ”は、それぞれ独立に、少なくとも１つの水素原子がフッ素原子で置換された炭素数１〜１０のアルキル基を表す。］

[Wherein X ″ represents an alkylene group having 2 to 6 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom; Y ″ and Z ″ each independently represent at least one hydrogen atom as a fluorine atom; Represents an alkyl group having 1 to 10 carbon atoms substituted with

X ″ is a linear or branched alkylene group in which at least one hydrogen atom is substituted with a fluorine atom, and the alkylene group has 2 to 6 carbon atoms, preferably 3 to 5 carbon atoms, Most preferably, it has 3 carbon atoms.
Y ″ and Z ″ are each independently a linear or branched alkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and the alkyl group has 1 to 10 carbon atoms, Has 1 to 7 carbon atoms, more preferably 1 to 3 carbon atoms.
The carbon number of the alkylene group of X ″ or the carbon number of the alkyl group of Y ″ and Z ″ is preferably as small as possible because the solubility in the resist solvent is good within the above carbon number range.
In addition, in the alkylene group of X ″ or the alkyl group of Y ″ and Z ″, the strength of the acid increases as the number of hydrogen atoms substituted with fluorine atoms increases, and high-energy light or electron beam of 200 nm or less The ratio of fluorine atoms in the alkylene group or alkyl group, that is, the fluorination rate is preferably 70 to 100%, more preferably 90 to 100%, and most preferably all. Are a perfluoroalkylene group or a perfluoroalkyl group in which a hydrogen atom is substituted with a fluorine atom.

In the general formula (b-1) or (b-2), the anion moiety (R ⁴ ″ SO ₃ ⁻ ) is R ⁷ ″ -COO ⁻ [wherein R ⁷ ″ is an alkyl group or a fluorinated alkyl group. An onium salt-based acid generator replaced with a cation group can be used (the cation moiety is the same as (b-1) or (b-2)).
Examples of R ⁷ ″ include the same as R ⁴ ″ described above.
Specific examples of the “R ⁷ ″ —COO ⁻ ” include trifluoroacetate ion, acetate ion, 1-adamantanecarboxylate ion and the like.

  Moreover, the sulfonium salt which has a cation part represented by the following general formula (b-5) or (b-6) can also be used as an onium salt type | system | group acid generator.

［式中、Ｒ^４１〜Ｒ^４６はそれぞれ独立してアルキル基、アセチル基、アルコキシ基、カルボキシ基、水酸基またはヒドロキシアルキル基であり；ｎ_１〜ｎ_５はそれぞれ独立して０〜３の整数であり、ｎ_６は０〜２の整数である。］

[Wherein R ^{41 to} R ⁴⁶ are each independently an alkyl group, acetyl group, alkoxy group, carboxy group, hydroxyl group or hydroxyalkyl group; n _{1 to} n ₅ are each independently an integer of 0 to 3; There, _{n 6} is an integer of 0-2. ]

In R ^{41 to} R ⁴⁶ , the alkyl group is preferably an alkyl group having 1 to 5 carbon atoms, more preferably a linear or branched alkyl group, and a methyl group, an ethyl group, a propyl group, an isopropyl group, n A butyl group or a tert-butyl group is particularly preferable.
The alkoxy group is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a linear or branched alkoxy group, and particularly preferably a methoxy group or an ethoxy group.
The hydroxyalkyl group is preferably a group in which one or more hydrogen atoms in the alkyl group are substituted with a hydroxy group, and examples thereof include a hydroxymethyl group, a hydroxyethyl group, and a hydroxypropyl group.
When the symbols n _{1 to} n ₆ attached to R ^{41 to} R ⁴⁶ are integers of 2 or more, the plurality of R ^{41 to} R ⁴⁶ may be the same or different.
n ₁ is preferably 0 to 2, more preferably 0 or 1, and still more preferably 0.
n ₂ and n ₃ are preferably each independently 0 or 1, more preferably 0.
n ₄ is preferably 0 to 2, more preferably 0 or 1.
n ₅ is preferably 0 or 1, more preferably 0.
n ₆ is preferably 0 or 1, more preferably 1.

The anion part of the sulfonium salt having a cation part represented by the formula (b-5) or (b-6) is not particularly limited, and is the same as the anion part of the onium salt acid generators proposed so far. It may be a thing. Such anion portion, for example, the general formula (b-1) or the onium salt-based acid generator represented by (b-2) (R 4 "SO 3 -) fluorinated such as alkyl sulfonate ion The anion part represented by the general formula (b-3) or (b-4) and the like.

  In this specification, the oxime sulfonate acid generator is a compound having at least one group represented by the following general formula (B-1), and has a property of generating an acid upon irradiation with radiation. is there. Such oxime sulfonate-based acid generators are frequently used for chemically amplified resist compositions, and can be arbitrarily selected and used.

（式（Ｂ−１）中、Ｒ^３１、Ｒ^３２はそれぞれ独立に有機基を表す。）

(In formula (B-1), R ³¹ and R ³² each independently represents an organic group.)

The organic groups of R ³¹ and R ³² are groups containing carbon atoms, and atoms other than carbon atoms (for example, hydrogen atoms, oxygen atoms, nitrogen atoms, sulfur atoms, halogen atoms (fluorine atoms, chlorine atoms, etc.), etc.) You may have.
As the organic group for R ^31, a linear, branched, or cyclic alkyl group or aryl group is preferable. These alkyl groups and aryl groups may have a substituent. There is no restriction | limiting in particular as this substituent, For example, a fluorine atom, a C1-C6 linear, branched or cyclic alkyl group etc. are mentioned. Here, “having a substituent” means that part or all of the hydrogen atoms of the alkyl group or aryl group are substituted with a substituent.
As an alkyl group, C1-C20 is preferable, C1-C10 is more preferable, C1-C8 is more preferable, C1-C6 is especially preferable, and C1-C4 is the most preferable. As the alkyl group, a partially or completely halogenated alkyl group (hereinafter sometimes referred to as a halogenated alkyl group) is particularly preferable. The partially halogenated alkyl group means an alkyl group in which a part of hydrogen atoms is substituted with a halogen atom, and the fully halogenated alkyl group means that all of the hydrogen atoms are halogen atoms. Means an alkyl group substituted with Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable. That is, the halogenated alkyl group is preferably a fluorinated alkyl group.
The aryl group preferably has 4 to 20 carbon atoms, more preferably 4 to 10 carbon atoms, and most preferably 6 to 10 carbon atoms. As the aryl group, a partially or completely halogenated aryl group is particularly preferable. The partially halogenated aryl group means an aryl group in which a part of hydrogen atoms is substituted with a halogen atom, and the fully halogenated aryl group means that all of the hydrogen atoms are halogen atoms. Means an aryl group substituted with.
R ³¹ is particularly preferably an alkyl group having 1 to 4 carbon atoms having no substituent or a fluorinated alkyl group having 1 to 4 carbon atoms.
As the organic group for R ^32, a linear, branched, or cyclic alkyl group, aryl group, or cyano group is preferable. As the alkyl group and aryl group for R ^32, the same alkyl groups and aryl groups as those described above for R ³¹ can be used.
R ³² is particularly preferably a cyano group, an alkyl group having 1 to 8 carbon atoms having no substituent, or a fluorinated alkyl group having 1 to 8 carbon atoms.

  More preferable examples of the oxime sulfonate-based acid generator include compounds represented by the following general formula (B-2) or (B-3).

［式（Ｂ−２）中、Ｒ^３３は、シアノ基、置換基を有さないアルキル基またはハロゲン化アルキル基である。Ｒ^３４はアリール基である。Ｒ^３５は置換基を有さないアルキル基またはハロゲン化アルキル基である。］

[In Formula (B-2), R ³³ represents a cyano group, an alkyl group having no substituent, or a halogenated alkyl group. R ³⁴ is an aryl group. R ³⁵ represents an alkyl group having no substituent or a halogenated alkyl group. ]

［式（Ｂ−３）中、Ｒ^３６はシアノ基、置換基を有さないアルキル基またはハロゲン化アルキル基である。Ｒ^３７は２または３価の芳香族炭化水素基である。Ｒ^３８は置換基を有さないアルキル基またはハロゲン化アルキル基である。ｐ”は２または３である。］

[In Formula (B-3), R ³⁶ represents a cyano group, an alkyl group having no substituent, or a halogenated alkyl group. R ³⁷ is a divalent or trivalent aromatic hydrocarbon group. ^R38 is an alkyl group having no substituent or a halogenated alkyl group. p ″ is 2 or 3.]

In the general formula (B-2), alkyl or halogenated alkyl group having no substituent group for R ³³ preferably has 1 to 10 carbon atoms, 1 to 8 carbon atoms, more preferably, carbon Numbers 1 to 6 are most preferable.
R ³³ is preferably a halogenated alkyl group, more preferably a fluorinated alkyl group.
The fluorinated alkyl group for R ³³ is preferably such that the hydrogen atom of the alkyl group is 50% or more fluorinated, more preferably 70% or more fluorinated, and 90% or more fluorinated. Particularly preferred.
As the aryl group of R ³⁴ , one hydrogen atom is removed from an aromatic hydrocarbon ring such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, or a phenanthryl group. And a heteroaryl group in which a part of carbon atoms constituting the ring of these groups is substituted with a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom. Among these, a fluorenyl group is preferable.
The aryl group of R ³⁴ may have a substituent such as an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group, or an alkoxy group. The alkyl group or halogenated alkyl group in the substituent preferably has 1 to 8 carbon atoms, and more preferably 1 to 4 carbon atoms. The halogenated alkyl group is preferably a fluorinated alkyl group.
Alkyl group or halogenated alkyl group having no substituent group for R ³⁵ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, 1 to 6 carbon atoms are most preferred.
R ³⁵ is preferably a halogenated alkyl group, more preferably a fluorinated alkyl group.
The fluorinated alkyl group for R ³⁵ is preferably such that the hydrogen atom of the alkyl group is 50% or more fluorinated, more preferably 70% or more fluorinated, and 90% or more fluorinated. Particularly preferred is the strength of the acid generated. Most preferably, it is a fully fluorinated alkyl group in which a hydrogen atom is 100% fluorine-substituted.

In the general formula (B-3), the alkyl group or halogenated alkyl group having no substituent for R ³⁶ is the same as the alkyl group or halogenated alkyl group having no substituent for R ^33. Is mentioned.
Examples of the divalent or trivalent aromatic hydrocarbon group for R ³⁷ include groups obtained by further removing one or two hydrogen atoms from the aryl group for R ³⁴ .
Examples of the alkyl group or halogenated alkyl group having no substituent of R ³⁸ include the same alkyl groups or halogenated alkyl groups having no substituent as R ³⁵ described above.
p ″ is preferably 2.

Specific examples of the oxime sulfonate acid generator include α- (p-toluenesulfonyloxyimino) -benzyl cyanide, α- (p-chlorobenzenesulfonyloxyimino) -benzyl cyanide, α- (4-nitrobenzenesulfonyloxy). Imino) -benzylcyanide, α- (4-nitro-2-trifluoromethylbenzenesulfonyloxyimino) -benzylcyanide, α- (benzenesulfonyloxyimino) -4-chlorobenzylcyanide, α- (benzenesulfonyl) Oxyimino) -2,4-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -2,6-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -4-methoxybenzyl cyanide, α- ( 2-Chlorobenzenesulfonyloxyimino) 4-methoxybenzylcyanide, α- (benzenesulfonyloxyimino) -thien-2-ylacetonitrile, α- (4-dodecylbenzenesulfonyloxyimino) -benzylcyanide, α-[(p-toluenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α-[(dodecylbenzenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α- (tosyloxyimino) -4-thienyl cyanide, α- (methylsulfonyloxyimino) -1-cyclo Pentenyl acetonitrile, α- (methylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -1-cycloheptenylacetonitrile, α- (methylsulfonyloxyimino) -1-cyclooctene Acetonitrile, α- (trifluoromethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -cyclohexylacetonitrile, α- (ethylsulfonyloxyimino) -ethylacetonitrile, α- (propyl Sulfonyloxyimino) -propylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclopentylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclohexylacetonitrile, α- (cyclohexylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- ( Ethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclope N-tenyl acetonitrile, α- (n-butylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (ethylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclohexenylacetonitrile , Α- (n-butylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -phenylacetonitrile, α- (methylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (trifluoro Methylsulfonyloxyimino) -phenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (ethylsulfonyloxyimino) -p- Butoxy phenylacetonitrile, alpha-(propylsulfonyl oxyimino)-p-methylphenyl acetonitrile, alpha-like (methylsulfonyloxyimino)-p-bromophenyl acetonitrile.
Also, an oxime sulfonate-based acid generator disclosed in JP-A-9-208554 (paragraphs [0012] to [0014] [chemical formula 18] to [chemical formula 19]), WO 2004 / 074242A2 (pages 65 to 85). The oxime sulfonate acid generators disclosed in Examples 1 to 40) of No. 1 can also be suitably used.
Moreover, the following can be illustrated as a suitable thing.

Among diazomethane acid generators, specific examples of bisalkyl or bisarylsulfonyldiazomethanes include bis (isopropylsulfonyl) diazomethane, bis (p-toluenesulfonyl) diazomethane, bis (1,1-dimethylethylsulfonyl) diazomethane, Examples include bis (cyclohexylsulfonyl) diazomethane, bis (2,4-dimethylphenylsulfonyl) diazomethane, and the like.
Further, diazomethane acid generators disclosed in JP-A-11-035551, JP-A-11-035552, and JP-A-11-035573 can also be suitably used.
Examples of poly (bissulfonyl) diazomethanes include 1,3-bis (phenylsulfonyldiazomethylsulfonyl) propane and 1,4-bis (phenylsulfonyldiazo) disclosed in JP-A-11-322707. Methylsulfonyl) butane, 1,6-bis (phenylsulfonyldiazomethylsulfonyl) hexane, 1,10-bis (phenylsulfonyldiazomethylsulfonyl) decane, 1,2-bis (cyclohexylsulfonyldiazomethylsulfonyl) ethane, 1,3 -Bis (cyclohexylsulfonyldiazomethylsulfonyl) propane, 1,6-bis (cyclohexylsulfonyldiazomethylsulfonyl) hexane, 1,10-bis (cyclohexylsulfonyldiazomethylsulfonyl) decane, etc. Door can be.

(B) As a component, these acid generators may be used individually by 1 type, and may be used in combination of 2 or more type.
In the present invention, it is particularly preferable to use an onium salt having a fluorinated alkyl sulfonate ion as an anion as the component (B).
In the resist composition, the content of the component (B) is preferably 0.5 to 50 parts by mass and more preferably 1 to 40 parts by mass with respect to 100 parts by mass of the component (A). By setting it within the above range, pattern formation is sufficiently performed. Moreover, since a uniform solution is obtained and storage stability becomes favorable, it is preferable.

<Optional component>
A nitrogen-containing organic compound component (D) (hereinafter referred to as “component (D)”) can be added to the resist composition as an optional component.
The component (D) is not particularly limited as long as it acts as an acid diffusion control agent, that is, a quencher that traps the acid generated from the component (B) by exposure. Therefore, any known one may be used, and aliphatic amines, particularly secondary aliphatic amines and tertiary aliphatic amines are particularly preferable. An aliphatic amine is an amine having one or more aliphatic groups, and the aliphatic groups preferably have 1 to 12 carbon atoms.
Examples of the aliphatic amine include an amine (alkyl amine or alkyl alcohol amine) or a cyclic amine in which at least one hydrogen atom of ammonia NH ₃ is substituted with an alkyl group or hydroxyalkyl group having 12 or less carbon atoms.
Specific examples of alkylamines and alkyl alcohol amines include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine; diethylamine, di-n-propylamine, di- -Dialkylamines such as n-heptylamine, di-n-octylamine, dicyclohexylamine; trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-hexylamine, tri-n-pentylamine Trialkylamines such as tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decylamine, tri-n-dodecylamine; diethanolamine, triethanolamine, diisopropanolamine, Li isopropanolamine, di -n- octanol amines, alkyl alcohol amines tri -n- octanol amine. Among these, a trialkylamine having 5 to 10 carbon atoms is more preferable, and a tri-n-alkylamine having 5 to 10 carbon atoms is most preferable.
Examples of the cyclic amine include heterocyclic compounds containing a nitrogen atom as a hetero atom. The heterocyclic compound may be monocyclic (aliphatic monocyclic amine) or polycyclic (aliphatic polycyclic amine).
Specific examples of the aliphatic monocyclic amine include piperidine and piperazine.
As the aliphatic polycyclic amine, those having 6 to 10 carbon atoms are preferable. Specifically, 1,5-diazabicyclo [4.3.0] -5-nonene, 1,8-diazabicyclo [5. 4.0] -7-undecene, hexamethylenetetramine, 1,4-diazabicyclo [2.2.2] octane, and the like.
These may be used alone or in combination of two or more.
(D) component is normally used in 0.01-5.0 mass parts with respect to 100 mass parts of (A) component. By setting the content in the above range, the resist pattern shape, the stability over time, and the like are improved.

In addition, the resist composition includes, as an optional component, a group consisting of an organic carboxylic acid, a phosphorus oxo acid, and derivatives thereof for the purpose of preventing sensitivity deterioration and improving the resist pattern shape and stability with time. At least one compound (E) selected from (hereinafter referred to as component (E)) can be contained.
As the organic carboxylic acid, for example, acetic acid, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, salicylic acid and the like are suitable.
Examples of phosphorus oxo acids and derivatives thereof include phosphoric acid, phosphonic acid, phosphinic acid and the like, and among these, phosphonic acid is particularly preferable.
Examples of the oxo acid derivative of phosphorus include esters in which the hydrogen atom of the oxo acid is substituted with a hydrocarbon group, and the hydrocarbon group includes an alkyl group having 1 to 5 carbon atoms and 6 to 6 carbon atoms. 15 aryl groups and the like.
Examples of phosphoric acid derivatives include phosphoric acid esters such as di-n-butyl phosphate and diphenyl phosphate.
Examples of phosphonic acid derivatives include phosphonic acid esters such as phosphonic acid dimethyl ester, phosphonic acid-di-n-butyl ester, phenylphosphonic acid, phosphonic acid diphenyl ester, and phosphonic acid dibenzyl ester.
Examples of phosphinic acid derivatives include phosphinic acid esters such as phenylphosphinic acid.
(E) A component may be used individually by 1 type and may use 2 or more types together.
As the component (E), an organic carboxylic acid is preferable, and salicylic acid is particularly preferable.
(E) A component is used in the ratio of 0.01-5.0 mass parts per 100 mass parts of (A) component.

  If desired, the resist composition may further contain miscible additives such as an additional resin for improving the performance of the resist film, a surfactant for improving the coating property, a dissolution inhibitor, a plasticizer, and a stabilizer. A coloring agent, a coloring agent, an antihalation agent, a dye, and the like can be appropriately added and contained.

The resist composition can be produced by dissolving the material in an organic solvent (hereinafter sometimes referred to as (S) component).
As the component (S), any component can be used as long as it can dissolve each component to be used to form a uniform solution. It can be appropriately selected and used.
For example, lactones such as γ-butyrolactone;
Ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-pentyl ketone, methyl isopentyl ketone, 2-heptanone;
Polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol;
Compounds having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, dipropylene glycol monoacetate, monomethyl ether, monoethyl ether, monopropyl of the polyhydric alcohols or the compound having an ester bond Derivatives of polyhydric alcohols such as ethers, monoalkyl ethers such as monobutyl ether or compounds having an ether bond such as monophenyl ether [in these, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME) Is preferred];
Cyclic ethers such as dioxane and esters such as methyl lactate, ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate;
Aromatic organic solvents such as anisole, ethyl benzyl ether, cresyl methyl ether, diphenyl ether, dibenzyl ether, phenetol, butyl phenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, mesitylene, etc. be able to.

These organic solvents may be used independently and may be used as 2 or more types of mixed solvents.
Of these, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), and EL are preferable.
Moreover, the mixed solvent which mixed PGMEA and the polar solvent is also preferable. The blending ratio (mass ratio) may be appropriately determined in consideration of the compatibility between PGMEA and the polar solvent, preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. It is preferable to be within the range.
More specifically, when EL is blended as a polar solvent, the mass ratio of PGMEA: EL is preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. Moreover, when mix | blending PGME as a polar solvent, the mass ratio of PGMEA: PGME becomes like this. Preferably it is 1: 9-9: 1, More preferably, it is 2: 8-8: 2, More preferably, it is 3: 7-7: 3.
In addition, as the component (S), a mixed solvent of at least one selected from PGMEA and EL and γ-butyrolactone is also preferable. In this case, the mixing ratio of the former and the latter is preferably 70:30 to 95: 5.

In the pattern formation method, when the resist pattern is formed by a double patterning process, the second resist composition is applied onto the first resist pattern, so that the (S) component of the second resist composition is used. It is preferable to use an organic solvent that does not dissolve the first resist pattern. Examples of the organic solvent include the same solvents as those described above for the component (S ′) of the material for forming a reverse pattern of the present invention.
However, in this case, as the (S ′) component of the material for forming an inverted pattern, it is used for these resist compositions so that both the first resist pattern and the resist pattern formed with the second resist composition are not dissolved. It is preferable to use a different organic solvent. For example, when an alcohol-based organic solvent is used as the (S) component of the second resist composition, an ether-based organic solvent having no hydroxyl group is preferably used as the (S ′) component of the reversal pattern forming material.

  The amount of the component (S) used is not particularly limited, but is a concentration that can be applied to a substrate or the like and is appropriately set according to the coating film thickness. In general, the solid content concentration of the resist composition is 0. .5 to 20% by mass, preferably 1 to 15% by mass.

  Although the chemical amplification resist composition has been described in detail above, the present invention is not limited to this, and a non-chemical amplification resist composition may be used as the resist composition. As the non-chemically amplified resist composition, those conventionally proposed as radiation-sensitive compositions can be used, such as alkali-soluble resins such as novolak resins and hydroxystyrene resins, and naphthoquinonediazide group-containing compounds. And a resist composition containing a photosensitive component. The resist composition may contain a sensitizer as necessary.

  EXAMPLES Hereinafter, the present invention will be described with reference to examples, but the scope of the present invention is not limited to these examples.

[Preparation of resist composition]
Each component shown in Table 1 was mixed and dissolved to prepare a resist composition (positive type).

Each abbreviation in Table 1 has the following meaning. Moreover, the numerical value in [] of Table 1 is a compounding quantity (mass part).
(A) -1: a copolymer having a mass average molecular weight (Mw) of 7000 and a dispersity of 1.4 represented by the following chemical formula (A) -1. In the formula, the symbol at the lower right of () indicates the ratio (mol%) of the structural unit to which the symbol is attached, and is a1 / a2 / a3 = 30/50/20.
(B) -1: Di (1-naphthyl) phenylsulfonium nonafluoro-n-butanesulfonate.
(D) -1: tri-n-pentylamine.
(E) -1: salicylic acid.
(S) -1: γ-butyrolactone.
(S) -2: Mixed solvent of PGMEA / PGME = 6/4 (mass ratio).

[Preparation of reversal pattern forming material (Ti-based)]
Tetraisopropoxytitanium 18.8 g, ethanol 5.6 g, and acetic acid 6.7 g were added to the flask, reacted at 25 ° C. for 3 hours with stirring, and aged for 12 hours. Thereafter, 19.9 g of acetylacetone was added and reacted at 25 ° C. for 6 hours.
Polymer (X) -1 contained in the reaction solution thus obtained had a hydrolysis rate of 100% and a chelate rate of 100%.
Ethanol was added to the reaction solution to adjust the solid content concentration to 7% by mass, and this was used as a pattern reversal coating material (Ti-1).

[Preparation of reverse pattern forming material (Si-based)]
The following Si-containing polymer (X ′)-1 was dissolved in diisopentyl ether (DIAE) to prepare a reversal pattern forming material (Si-1) having a resin concentration of 5 mass%.
(X ′)-1: a copolymer represented by the following chemical formula (X) -2 [where m / n = 70/30 (mol%)] (manufactured by Toray Fine Co., Ltd., Mw = 10000, silicon content) : 15%).

[Test Example 1 (Evaluation of etching selectivity)]
(1)
Using the organic antireflection film composition “ARC29” (trade name, manufactured by Brewer Science Co., Ltd.), the resist composition 1, the pattern reversal coating material (Ti-1), and (Si-1), Film formation with a film thickness of 500 nm (single solid film formation without a pattern) was performed.
Formation of organic antireflection film ARC29: An organic antireflection film composition “ARC29A” is applied onto a silicon wafer by using a spinner, and baked at 205 ° C. on a hot plate and dried. An antireflection film was formed.
Formation of resist film 1: The resist composition 1 was applied onto a silicon wafer using a spinner, and baked at 110 ° C. on a hot plate and dried to form a resist film.
Formation of pattern reversal coating (Ti-1): The pattern reversal coating material (Ti-1) is applied onto a silicon wafer at a rotational speed of 1500 rpm using a spinner, and baked at 90 ° C. on a hot plate. Then, a pattern reversal coating (Ti-1) having a film thickness of about 500 nm was formed by drying.
Formation of pattern reversal coating (Si-1): The pattern reversal coating (Ti-1) except that the pattern reversal coating material (Si-1) is used instead of the pattern reversal coating material (Ti-1). A pattern reversal coating (Si-1) having a film thickness of about 500 nm was formed by the same procedure as the formation of.

(2)
Using a plasma etching apparatus (manufactured by Tokyo Ohka Kogyo Co., Ltd., apparatus name: TCA-2400), a mixed gas (flow rate) of O ₂ gas and N ₂ gas is applied to the wafer on which each film is formed in (1) above. Oxygen plasma etching treatment (pressure: 300 mTorr (about 40 Pa); RF: 200 W; temperature: 60 ° C .; treatment time: 30 seconds) by a ratio: O ₂ / N ₂ = 60/40).
The amount of film loss at this time is measured, and the value converted into the amount of film reduction per minute is calculated as an etch rate (etch rate (thickness of the film etched per unit time) (unit: nm / min)). did.
From the obtained results, it was evaluated how many times the resist film 1 had an etching rate (etching selectivity) of each pattern reversal film. The results are shown in Table 2.

As shown in the above results, the pattern reversal film (Ti-1) formed using the pattern reversal film material (Ti-1) has high etching selectivity with respect to the organic antireflection film and the resist film. It was.
Thus, since the etching selectivity with respect to the resist film and the organic antireflection film during O ₂ plasma etching is large, the pattern reversal coating material (Ti-1) is a pattern reversal coating material for forming a reversal pattern. It was confirmed that it was useful as.

  DESCRIPTION OF SYMBOLS 1 ... Board | substrate, 2 ... Underlayer film, 3 ... Resist pattern, 4 ... Pattern reversal film, 4a ... Reverse pattern, 11 ... 1st resist film, 12 ... 2nd resist film, 21 ... Photomask, 22 ... Photo mask.

Claims (3)

A step (i) of forming a resist pattern on the support using a resist composition;
(Ii) forming a pattern reversal film by applying a reversal pattern forming material on the support on which the resist pattern is formed;
Removing the resist pattern by etching to form a reverse pattern (iii),
The pattern forming method, wherein the reverse pattern forming material contains a titanium-containing polymer (T) formed by dehydration condensation of a hydrolyzate of tetraalkoxytitanium.   The pattern forming method according to claim 1, wherein the reverse pattern forming material contains an organic solvent (S1) that does not dissolve the resist pattern.   The pattern forming method according to claim 2, wherein the organic solvent (S1) is at least one selected from the group consisting of an alcohol-based organic solvent and an ether-based organic solvent having no hydroxyl group.

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