JP2016200761A - Method for forming negative resist pattern and composition for forming overlay film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming a negative resist pattern and a composition for forming an overlay film, by which water repellency on a surface of an overlay film can be increased and a resist pattern with fewer development defects can be formed.SOLUTION: The method for forming a negative resist pattern includes steps of: forming a resist film; forming an overlay film from a composition for forming an overlay film on one surface of the resist film; subjecting the resist film with the overlay film formed to immersion exposure; and developing the resist film subjected to the immersion exposure by use of a developer containing an organic solvent. The composition for forming an overlay film comprises: a polymer component comprising a first polymer having a first structural unit containing an alicyclic structure and a second structural unit containing a fluorine atom except for the first structural unit; and a solvent. The content percentage of fluorine atoms in the polymer component is 2 mass% or more and 30 mass% or less.SELECTED DRAWING: None

Description

  The present invention relates to a negative resist pattern forming method and an upper layer film forming composition.

  Along with miniaturization of various electronic device structures such as semiconductor devices and liquid crystal devices, miniaturization of resist patterns in lithography processes is required. At present, a fine resist pattern having a line width of about 90 nm can be formed using, for example, an ArF excimer laser. However, in the future, a finer resist pattern will be required.

  In response to the above requirements, as a technique for improving the resolution of a conventional chemically amplified radiation-sensitive resin composition without increasing the number of processes using an existing apparatus, a negative polarity is obtained by using an organic solvent having a polarity lower than that of an alkaline aqueous solution as a developer. A technique for forming a mold resist pattern is known (see Japanese Patent Application Laid-Open No. 2000-199953). In other words, when forming a resist pattern using an alkaline aqueous solution as a developer, it is difficult to form a fine resist pattern due to poor optical contrast. Since the optical contrast can be increased, a finer resist pattern can be formed.

  Also in the development using such an organic solvent, immersion exposure is used to form a finer resist pattern. In this immersion exposure, an upper layer film (top coat) is formed on the resist film. (See JP 2008-309878).

  However, when an organic solvent is used as a developer as described above, when a resist pattern is formed, a bridge defect, a residue defect, a blob that is considered to be caused by undissolved residues in the developer such as a resist film and an upper layer film, etc. There is an inconvenience that a defect, and further, a development defect such as a disconnection defect considered to be caused by high solubility of the resist film and the upper layer film in the developing solution occurs. In addition, it is difficult to achieve both suppression of development defects by controlling solubility in a developing solution and increasing water repellency of the upper layer film surface during immersion exposure, and further increase the scanning speed of immersion exposure. It cannot meet the demand for improvement.

JP 2000-199953 A JP 2008-309878 A

  The present invention has been made based on the circumstances as described above, and the object thereof is to form a negative resist pattern that can increase the water repellency of the upper layer film surface and can form a resist pattern with few development defects. The object is to provide a method and a composition for forming an upper layer film.

  The invention made in order to solve the above problems includes a step of forming a resist film (hereinafter also referred to as “resist film forming step”), and an upper layer film is formed on one surface of the resist film by the upper layer film forming composition. A step (hereinafter also referred to as “upper layer forming step”), a step of performing immersion exposure on the resist film on which the upper layer film is formed (hereinafter also referred to as “immersion exposure step”), and a development containing an organic solvent. A step of developing the immersion-exposed resist film with a liquid (hereinafter also referred to as “development step”), which is also referred to as the upper layer film forming composition (hereinafter referred to as “upper layer film forming composition (I)”). ) In the same or different polymers, a first structural unit containing an alicyclic structure (hereinafter also referred to as “structural unit (I)”) and a second structural unit containing a fluorine atom other than the first structural unit (Hereinafter also referred to as “structural unit (II)”) Containing a polymer component (hereinafter also referred to as “[A] polymer component”) and a solvent (hereinafter also referred to as “[B] solvent”), and the fluorine atom content in the [A] polymer component Is a negative resist pattern forming method in which is 2 mass% or more and 30 mass% or less.

  Another invention made to solve the above problems is a composition for forming an upper layer film used in a negative resist pattern forming method using a developer containing an organic solvent, in the same or different polymers, A polymer component having a first structural unit containing an alicyclic structure and a second structural unit containing a fluorine atom other than the first structural unit, and a solvent, the fluorine atom content in the polymer component is It is 2 mass% or more and 30 mass% or less, It is characterized by the above-mentioned.

  According to the method for forming a negative resist pattern and the composition for forming an upper layer film of the present invention, in forming a negative pattern using a developer containing an organic solvent, the water repellency on the surface of the upper layer film can be increased and development defects can be achieved. A resist pattern with less can be formed. Therefore, the negative resist pattern forming method and the composition for forming an upper layer film can be suitably used for pattern formation in the field of semiconductor devices and the like that will require further miniaturization and higher quality in the future.

<Negative resist pattern forming method>
The negative resist pattern forming method of the present invention includes a resist film forming step, an upper layer film forming step, an immersion exposure step, and a developing step. In the negative resist pattern forming method, the upper layer film forming composition (I) is used as the upper layer film forming composition.

  The negative resist pattern forming method may further include a step of removing the upper layer film (hereinafter also referred to as “upper layer film removing step”) after the liquid immersion exposure step and before or at the same time as the development step. it can.

  According to the negative resist pattern forming method, since the composition for forming an upper layer film (I) is used, the water repellency on the surface of the upper layer film can be increased and a resist pattern with few development defects can be formed. Hereinafter, each step of the negative resist pattern forming method and the composition for forming an upper layer film (I) will be described.

[Resist film forming step]
In this step, a resist film is formed. The resist film is usually formed on a substrate using a radiation sensitive resin composition (hereinafter also referred to as “radiation sensitive resin composition (I)”). As a substrate to be used, a silicon wafer, a silicon wafer coated with aluminum, and the like are usually mentioned. Further, in order to maximize the characteristics of the resist film to be formed, an organic or inorganic antireflection film described in, for example, Japanese Patent Publication No. 6-12458 is formed on the surface of the substrate in advance. Is preferred.

  The type of the radiation-sensitive resin composition (I) is not particularly limited. Among the radiation-sensitive resin compositions (I) conventionally used for forming a resist film, the intended use of the resist It can be appropriately selected and used depending on the situation. Among these, the radiation sensitive resin composition (I) containing the polymer (P) containing an acid dissociable group and the acid generator (Q) is preferable.

  In the polymer (P), examples of the structural unit containing an acid dissociable group (hereinafter, also referred to as “structural unit (p)”) include a structural unit represented by the following formula (A).

In the above formula (A), R ^P represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ^p1 is a monovalent chain hydrocarbon group having 1 to 10 carbon atoms. R ^p2 and R ^p3 are each independently a monovalent chain hydrocarbon group having 1 to 10 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or these groups are It represents an alicyclic structure having 3 to 20 carbon atoms which is constituted together with the carbon atoms to which they are bonded.

The R ^P, from the viewpoint of copolymerizability of the monomer giving the structural units (p), preferably a hydrogen atom or a methyl group, more preferably a methyl group.

Examples of the monovalent chain hydrocarbon group having 1 to 10 carbon atoms represented by R ^p1 , R ^p2 and R ^p3 include a methyl group, an ethyl group, an n-propyl group, an i-butyl group and an n-butyl group. And an alkyl group.

Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms represented by R ^p2 and R ^p3 include monocyclic cycloalkyl groups such as a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group; a norbornyl group, an adamantyl group, and the like And a polycyclic cycloalkyl group.

  Examples of the ring structure having 3 to 20 carbon atoms formed together with the carbon atom to which these groups are bonded to each other include a monocyclic cycloalkane structure such as a cyclopentane structure and a cyclohexane structure; a norbornane structure and an adamantane structure And a polycyclic cycloalkane structure.

  Examples of the structural unit (p) include 1-alkyl-1-monocyclic cycloalkyl (meth) acrylates such as 1-ethyl-1-cyclopentyl (meth) acrylate; 2-i-propyl-2-adamantyl (meth) acrylate And other structural units derived from 2-alkyl-2-polycyclic cycloalkyl (meth) acrylates.

  In addition to the structural unit (p), the polymer (P) further has a structural unit containing a lactone structure, a cyclic carbonate structure, a sultone structure, or a combination thereof (hereinafter also referred to as “structural unit (q)”). Is preferred.

Examples of the structural unit (q) include a lactone structure, a norbornane lactone structure, a butyrolactone structure, and the like;
As cyclic carbonate structure, ethylene carbonate structure, propylene carbonate structure, etc .;
Examples of the sultone structure include structural units derived from (meth) acrylic acid esters including a norbornane sultone structure and a propane sultone structure.

  Moreover, the polymer (P) may have other structural units other than the structural unit (p) and the structural unit (q). Examples of other structural units include a structural unit containing a hydrocarbon group having 4 to 20 carbon atoms (hereinafter also referred to as “structural unit (r)”), a hydroxy group, a carboxy group, a sulfo group, a sulfonamide group, and the like. Examples thereof include a structural unit containing a polar group.

  As a minimum of the content rate of a structural unit (p), 20 mol% is preferable with respect to all the structural units which comprise a polymer (P), and 30 mol% is more preferable. As an upper limit of the said content rate, 70 mol% is preferable and 60 mol% is more preferable. By making the content rate of a structural unit (p) into the said range, lithography performance, such as the resolution of a resist pattern, can be improved.

  As a minimum of the content rate of a structural unit (q), 20 mol% is preferable with respect to all the structural units which comprise a polymer (P), and 30 mol% is more preferable. As an upper limit of the said content rate, 70 mol% is preferable and 60 mol% is more preferable. By setting the content ratio of the structural unit (q) in the above range, the solubility of the resist film formed from the radiation-sensitive resin composition (I) in the developer containing the organic solvent can be appropriately adjusted. In addition, the adhesion of the resist film to the substrate can be improved. As a result, the lithography performance such as the resolution of the resist pattern can be further improved.

  As an upper limit of the content rate of another structural unit, 20 mol% is preferable with respect to all the structural units which comprise a polymer (P), and 15 mol% is more preferable.

  The acid generator (Q) is a substance that generates an acid by radiation irradiation (exposure). Due to the action of the generated acid, the acid-dissociable group protecting the acidic group such as the carboxy group of the polymer (P) is dissociated in the exposed area to generate an acidic group. As a result, the polymer (P) has a reduced solubility in a developer containing an organic solvent in the exposed portion, and a negative resist pattern is formed.

  Examples of the acid generator (Q) include sulfonium salts, tetrahydrothiophenium salts, iodonium salts, phosphonium salts, diazonium salts, pyridinium salts and other onium salts, N-sulfonyloxyimide compounds, halogen-containing compounds, diazoketone compounds, and the like. Can be mentioned.

  Examples of the sulfonium salt include triphenylsulfonium nonafluoro-n-butanesulfonate, 4-cyclohexylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate, triphenylsulfonium 2- (bicyclo [2.2.1] hepta-2′- Yl) -1,1,2,2-tetrafluoroethanesulfonate, triphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1-difluoroethanesulfonate, and the like.

  Examples of the tetrahydrothiophenium salt include 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (4-n-butoxynaphthyl) tetrahydrothiophenium 2 -(Bicyclo [2.2.1] hepta-2'-yl) -1,1,2,2-tetrafluoroethanesulfonate and the like.

  The radiation sensitive resin composition (I) may contain other components such as an acid diffusion controller (R) and a surfactant in addition to the polymer (P) and the acid generator (Q). . Examples of the acid diffusion controller (R) include amine compounds such as trioctylamine and triethanolamine; R-(+)-(t-butoxycarbonyl) -2-piperidinemethanol, Nt-butoxycarbonyl-4- Examples include Nt-alkoxycarbonyl-containing amide compounds such as hydroxypiperidine; photodegradable bases such as triphenylsulfonium 10-camphorsulfonate and triphenylsulfonium salicylate.

  The radiation sensitive resin composition (I) is prepared by, for example, dissolving the polymer (P), the acid generator (Q) and, if necessary, the acid diffusion controller (R) in a solvent, and preferably the obtained mixture. Can be prepared by filtering with a filter having a pore size of about 0.2 μm. The lower limit of the total solid content concentration of the radiation-sensitive resin composition (I) is preferably 0.2% by mass, more preferably 0.5% by mass, and further preferably 1% by mass from the viewpoint of ease of application. The upper limit of the total solid content concentration is preferably 50% by mass, more preferably 30% by mass, and still more preferably 10% by mass.

  Examples of the coating method of the radiation sensitive resin composition (I) include conventionally known coating methods such as spin coating, cast coating, and roll coating. After applying on the substrate, pre-baking (PB) may be performed to volatilize the solvent. As a minimum of the temperature of PB, 50 degreeC is preferable and 80 degreeC is more preferable. As an upper limit of the said temperature, 150 degreeC is preferable and 120 degreeC is more preferable. The lower limit of the PB time is preferably 10 seconds, and more preferably 30 seconds. The upper limit of the time is preferably 600 seconds, and more preferably 300 seconds. As a minimum of average thickness of the resist film formed, 10 nm is preferred, 20 nm is more preferred, and 50 nm is still more preferred. The upper limit of the average thickness is preferably 1,000 nm, more preferably 500 nm, and even more preferably 200 nm.

[Upper layer formation process]
In this step, an upper layer film is formed on one surface of the resist film with the upper layer film forming composition (I). Examples of the method for applying the upper layer film-forming composition (I) include the same method as the method for applying the radiation-sensitive resin composition (I) in the resist film forming step. In this step, it is preferable to perform pre-baking (PB) after applying the upper layer film-forming composition (I). As a minimum of the temperature of PB, 50 degreeC is preferable and 80 degreeC is more preferable. As an upper limit of the said temperature, 150 degreeC is preferable and 120 degreeC is more preferable. The lower limit of the PB time is preferably 10 seconds, and more preferably 30 seconds. The upper limit of the time is preferably 600 seconds, and more preferably 300 seconds. As a minimum of the film thickness of the upper layer film formed, 10 nm is preferred, 20 nm is more preferred, and 50 nm is still more preferred. The upper limit of the film thickness is preferably 300 nm, more preferably 200 nm, and even more preferably 150 nm. Further, the thickness of the upper layer film to be formed is preferably as close as possible to λ / 4m (λ: wavelength of radiation, m: refractive index of the upper layer film). By doing in this way, the reflection suppression effect in the upper interface of a resist film can be enlarged.

  By forming an upper film on one side of the resist film, the immersion liquid and the resist film are not in direct contact with each other, so that the lithography performance of the resist film is reduced due to the immersion liquid penetrating the resist film. And contamination of the lens of the projection exposure apparatus by components eluted from the resist film into the immersion liquid is effectively suppressed.

[Immersion exposure process]
In this step, the resist film on which the upper layer film is formed is subjected to immersion exposure. This immersion exposure is performed by placing an immersion liquid on the upper layer film and exposing through the immersion liquid.

  As the immersion liquid, a liquid having a refractive index higher than that of air is usually used. As the immersion liquid, water is preferably used, and pure water is more preferably used. Note that the pH of the immersion liquid may be adjusted as necessary. In a state where the immersion liquid is interposed, that is, in a state where the immersion liquid is filled between the lens and the upper layer film of the exposure apparatus, exposure light is irradiated from the exposure apparatus and is passed through a mask having a predetermined pattern. To expose the resist film.

  The exposure light used for this immersion exposure can be appropriately selected according to the type of the resist film and the upper layer film. For example, visible light; ultraviolet light such as g-line and i-line; far ultraviolet light such as excimer laser light; Electromagnetic waves such as X-rays such as radiation; particle beams such as charged particle beams such as electron beams. Among these, far ultraviolet rays are preferable, ArF excimer laser light (wavelength 193 nm) and KrF excimer laser light (wavelength 248 nm) are more preferable, and ArF excimer laser light is more preferable. Moreover, the irradiation conditions of exposure light, for example, the exposure amount, etc. are appropriately determined according to the blended composition of the radiation-sensitive resin composition (I) and the upper layer film-forming composition (I), the types of additives contained therein, and the like. Can be set.

  After the immersion exposure, post-exposure baking (PEB) is preferably performed in order to improve the resolution, pattern shape, developability, and the like of the resulting resist pattern. The temperature of PEB can be appropriately set depending on the type of the radiation-sensitive resin composition (I) and the upper layer film-forming composition used. As a minimum of the temperature of PEB, 30 ° C is preferred and 50 ° C is more preferred. As an upper limit of the said temperature, 200 degreeC is preferable and 150 degreeC is more preferable. The lower limit of the PEB time is preferably 5 seconds, and more preferably 10 seconds. The upper limit of the time is preferably 600 seconds, and more preferably 300 seconds.

[Development process]
In this step, the immersion-exposed resist film is developed with a developer containing an organic solvent. Thereby, a desired negative resist pattern can be obtained.

  Examples of the organic solvent contained in the developer include alcohol solvents, ether solvents, ketone solvents, amide solvents, ester solvents, hydrocarbon solvents, and the like. As the organic solvent for the developer, those containing an ester solvent, a ketone solvent or a combination thereof are preferable. The said developing solution may contain the organic solvent individually by 1 type, and may contain 2 or more types.

Examples of the alcohol solvent include aliphatic monoalcohol solvents having 1 to 18 carbon atoms such as 4-methyl-2-pentanol and n-hexanol;
An alicyclic monoalcohol solvent having 3 to 18 carbon atoms such as cyclohexanol;
A C2-C18 polyhydric alcohol solvent such as 1,2-propylene glycol;
Examples thereof include C3-C19 polyhydric alcohol partial ether solvents such as propylene glycol monomethyl ether.

Examples of ether solvents include dialkyl ether solvents such as diethyl ether, dipropyl ether, dibutyl ether, dipentyl ether, diisoamyl ether, dihexyl ether, and diheptyl ether;
Cyclic ether solvents such as tetrahydrofuran and tetrahydropyran;
And aromatic ring-containing ether solvents such as diphenyl ether and anisole.

Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-iso-butyl ketone, 2-heptanone, ethyl-n-butyl ketone, methyl-n-hexyl ketone, Chain ketone solvents such as di-iso-butyl ketone and trimethylnonanone:
Cyclic ketone solvents such as cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone and methylcyclohexanone:
2,4-pentanedione, acetonylacetone, acetophenone and the like can be mentioned.

Examples of the amide solvent include cyclic amide solvents such as N, N′-dimethylimidazolidinone and N-methylpyrrolidone;
Examples thereof include chain amide solvents such as N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, and N-methylpropionamide.

Examples of ester solvents include monocarboxylic acid ester solvents such as n-butyl acetate and ethyl lactate;
Polyhydric alcohol carboxylate solvents such as propylene glycol acetate;
Polyhydric alcohol partial ether carboxylate solvents such as propylene glycol monomethyl ether acetate;
Polycarboxylic acid diester solvents such as diethyl oxalate;
Examples thereof include carbonate solvents such as dimethyl carbonate and diethyl carbonate.

Examples of the hydrocarbon solvent include aliphatic hydrocarbon solvents having 5 to 12 carbon atoms such as n-pentane and n-hexane;
Examples thereof include aromatic hydrocarbon solvents having 6 to 16 carbon atoms such as toluene and xylene.

  Among these, ester solvents, ketone solvents, ether solvents and combinations thereof are preferable, and ester solvents, ketone solvents and combinations thereof are more preferable. As the ester solvent, n-butyl acetate, isopropyl acetate and amyl acetate are preferable. As the ketone solvent, 2-butanone, methyl-n-butyl ketone and methyl-n-amyl ketone are preferable. As the ether solvent, anisole is preferable.

  As a minimum of content of the organic solvent in a developing solution, 80 mass% is preferred, 90 mass% is more preferred, 99 mass% is still more preferred, and 100 mass% is especially preferred. By setting the content of the organic solvent in the developer within the above range, the dissolution contrast between the exposed area and the unexposed area can be improved, and as a result, a resist pattern having better lithography performance can be formed. Can do. Examples of components other than the organic solvent include water and silicone oil.

  The developer may contain a nitrogen-containing compound. When the developer contains a nitrogen-containing compound, film loss in the formed resist pattern can be further reduced.

  As a nitrogen-containing compound, the compound etc. which were illustrated as a [C] compound of composition (I) for upper layer film formation mentioned below, for example are mentioned.

  An appropriate amount of a surfactant can be added to the developer as necessary. Examples of the surfactant include ionic and nonionic fluorine-based surfactants and silicon-based surfactants.

  As a developing method, for example, a method in which a substrate is immersed in a tank filled with a developer for a certain period of time (dip method), a method in which the developer is raised on the surface of the substrate by surface tension and is left stationary for a certain time (paddle method) ), A method of spraying the developer on the substrate surface (spray method), a method of continuously applying the developer while scanning the developer coating nozzle on the substrate rotating at a constant speed (dynamic dispensing method) Etc.

  In the development step, the resist film is preferably washed with a rinsing liquid after the development. An organic solvent can be used as the rinse liquid. By using an organic solvent as the rinsing liquid, the generated scum can be efficiently washed.

  Examples of the organic solvent used as the rinse liquid include hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents, and the like. Of these, alcohol solvents and ester solvents are preferred, and alcohol solvents are more preferred. As the alcohol solvent, a monovalent alcohol solvent having 6 to 8 carbon atoms is preferable.

  Examples of the monovalent alcohol solvent having 6 to 8 carbon atoms include linear, branched or cyclic monohydric alcohols, and specifically, 1-hexanol, 1-heptanol, 1-octanol. 4-methyl-2-pentanol, 2-hexanol, 2-heptanol, 2-octanol, 3-hexanol, 3-heptanol, 3-octanol, 4-octanol, benzyl alcohol and the like. Of these, 1-hexanol, 2-hexanol, 2-heptanol and 4-methyl-2-pentanol are preferred.

  The organic solvent contained in a rinse liquid may be used individually by 1 type, and may use 2 or more types together. The upper limit of the moisture content in the rinse liquid is preferably 10% by mass, more preferably 5% by mass, and still more preferably 3% by mass. By setting the water content in the rinsing liquid to the upper limit or less, good development characteristics can be obtained. A surfactant can be added to the rinse liquid.

  As a cleaning treatment method using a rinsing liquid, for example, a method of continuously applying the rinsing liquid onto a substrate rotating at a constant speed (rotary coating method), or a method of immersing the substrate in a tank filled with the rinsing liquid for a certain period of time (Dip method), a method (spray method) of spraying a rinsing liquid on the substrate surface, and the like.

[Upper layer removal process]
In this step, after the immersion exposure step, the upper layer film formed in the upper layer film formation step is removed simultaneously with or before the development step.

  The method for removing the upper layer film is not particularly limited, but a method that does not impair the lithography performance of the resist pattern is preferable. According to the negative resist pattern forming method, since the upper layer film is formed using the upper layer film forming composition (I), the upper layer film can be easily formed with a developer and / or a rinsing liquid in the development step. Can be removed. That is, the upper layer film can be removed in the development step, and a step for removing the upper layer film is not required separately from the development step.

<Upper layer film forming composition (I)>
The composition for forming an upper layer film (I) contains a [A] polymer component and a [B] solvent, and the fluorine atom content in the [A] polymer component is 2% by mass or more and 30% by mass or less. .

  By using the composition for forming an upper layer film (I), in forming a negative pattern using a developer containing an organic solvent, it is possible to increase the water repellency of the upper layer film surface and form a resist pattern with few development defects. can do. The reason why the composition for forming an upper layer film (I) in the negative resist pattern forming method has the above-described configuration to achieve the above-mentioned effects is not necessarily clear, but can be inferred as follows, for example. That is, the [A] polymer component has the structural unit (I) containing an alicyclic structure and the structural unit (II) containing a fluorine atom, so that each of these structural units is appropriately phase-separated in the upper layer film. Arrange. As a result, it is possible to suppress the occurrence of development defects by improving the solubility in a developer containing an organic solvent by the structural unit (I), and to further increase the water repellency of the upper layer film surface by the structural unit (II). It is considered possible.

  The upper film-forming composition (I) is used in a negative resist pattern forming method using a developer containing an organic solvent. According to the negative resist pattern forming method using a developer containing an organic solvent, the optical contrast can be increased as compared with the positive resist pattern forming method using a developer such as an alkaline aqueous solution. A resist pattern can be formed.

  The upper layer film-forming composition (I) contains a [A] polymer component and a [B] solvent, and as a suitable component, [C] a basic compound, a compound that generates a basic compound by the action of an acid, or these (Hereinafter also referred to as “[C] compound”) may be contained, and other components may be contained as long as the effects of the present invention are not impaired. Hereinafter, each component will be described.

<[A] Polymer component>
[A] The polymer component has the structural unit (I) and the structural unit (II) in the same or different polymers.

[A] As an aspect of a polymer component, the following [A1] polymer component, [A2] polymer component, etc. are mentioned, for example.
[A1] Polymer component: a first polymer having a structural unit (I) (hereinafter also referred to as “polymer (a)”) and a second polymer having a structural unit (II) (hereinafter referred to as “polymer”). (B) ").
[A2] Polymer component: includes a third polymer having a structural unit (I) and a structural unit (II) (hereinafter also referred to as “polymer (c)”).

  The polymer (a) may have other structural units such as structural units (III) to (V) described later in addition to the structural unit (I). The polymer (b) may have other structural units such as the structural units (III) to (V) in addition to the structural unit (II). The polymer (c) may have other structural units such as the structural units (III) to (V) in addition to the structural unit (I) and the structural unit (II).

  [A1] The polymer component may contain a polymer other than the polymer (a) and the polymer (b). [A2] The polymer component may contain a polymer other than the polymer (c). Hereinafter, each structural unit will be described.

[Structural unit (I)]
The structural unit (I) is a structural unit containing an alicyclic structure.

Examples of the alicyclic structure include monocyclic cycloalkane structures such as a cyclopropane structure, a cyclobutane structure, a cyclopentane structure, a cyclohexane structure, a cyclooctane structure, a cyclodecane structure, and a cyclododecane structure;
Monocyclic structures such as monocyclic cycloalkene structures such as cyclopropene structure, cyclobutene structure, cyclopentene structure, cyclohexene structure, cyclooctene structure, cyclodecene structure, cyclododecene structure,
Polycyclic cycloalkane structures such as norbornane structure, adamantane structure, tricyclodecane structure and tetracyclododecane structure;
Examples thereof include polycyclic structures such as a polycyclic cycloalkene structure such as a norbornene structure, a tricyclodecene structure, and a tetracyclododecene structure.

Among these, a polycyclic structure is preferable, a polycyclic cycloalkane structure is more preferable, a structure having three rings is more preferable, a tricyclodecane structure is particularly preferable, and tricyclo [5.2.1.0 ^{2, 6} ] A decane structure is more particularly preferred.

  Examples of the structural unit (I) include a structural unit derived from a (meth) acrylic acid ester having an alicyclic structure (hereinafter also referred to as “structural unit (I-1)”), and exo-methylene lactone having an alicyclic structure. And a structural unit derived from cycloolefin (hereinafter, also referred to as “structural unit (I-3)”), and the like. Examples of the structural unit (I-1) include a structural unit represented by the following formula (1-1) (hereinafter also referred to as “structural unit (I-1a)”). Examples of the structural unit (I-2) include a structural unit represented by the following formula (1-2) (hereinafter also referred to as “structural unit (I-2a)”). Examples of the cycloolefin include substituted or unsubstituted norbornene, substituted or unsubstituted tricyclodecene, substituted or unsubstituted tetracyclododecene, and the like.

In said formula (1-1), R < ¹ > is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. L is a single bond or a divalent organic group having 1 to 20 carbon atoms. R ² is a substituted or unsubstituted monovalent alicyclic hydrocarbon group having 3 to 20 ring members.
In said formula (1-2), R < ^{1 '>} is a hydrogen atom or a methyl group. Y ¹ , Y ² and Y ³ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. a is an integer of 1 to 4. When a is 2 or more, the plurality of Y ¹ may be the same or different, and the plurality of Y ² may be the same or different. L ′ is a single bond or a divalent organic group having 1 to 20 carbon atoms. R ^{2 ′} is a substituted or unsubstituted monovalent alicyclic hydrocarbon group having 3 to 20 ring members.

R ¹ is preferably a hydrogen atom or a methyl group, more preferably a methyl group, from the viewpoint of copolymerization of the monomer that gives the structural unit (I-1). R ^{1 ′} is preferably a hydrogen atom from the viewpoint of the copolymerizability of the monomer giving the structural unit (I-2).

  Examples of the divalent organic group having 1 to 20 carbon atoms represented by L and L ′ include, for example, a divalent hydrocarbon group having 1 to 20 carbon atoms, a carbon-carbon boundary of this hydrocarbon group or a bond side. Examples include a group (α) containing a divalent heteroatom-containing group at the terminal, a group obtained by substituting part or all of the hydrogen atoms of the hydrocarbon group and the group (α) with a monovalent heteroatom-containing group. It is done.

  L and L ′ are preferably a single bond and a chain hydrocarbon group having 1 to 5 carbon atoms, more preferably a single bond and a methanediyl group, and even more preferably a single bond.

Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 ring members represented by R ² and R ^{2 ′} include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclooctyl group, a cyclodecyl group, a cyclo Monocyclic cycloalkyl groups such as dodecyl groups;
A monocyclic alicyclic hydrocarbon group such as a monocyclic cycloalkenyl group such as cyclopropenyl group, cyclobutenyl group, cyclopentenyl group, cyclohexenyl group, cyclooctenyl group, cyclodecenyl group, cyclododecenyl group,
A polycyclic cycloalkyl group such as a norbornyl group, an adamantyl group, a tricyclodecyl group, a tetracyclododecyl group;
And polycyclic alicyclic hydrocarbon groups such as a polycyclic cycloalkenyl group such as a norbornenyl group, a tricyclodecenyl group, and a tetracyclododecyl group.

  Examples of the substituent for the alicyclic hydrocarbon group include a hydrocarbon group having 1 to 10 carbon atoms, a hydroxy group, a cyano group, a nitro group, and a sulfanyl group.

R ² and R ^{2 ′} are preferably an unsubstituted alicyclic hydrocarbon group, more preferably a polycyclic alicyclic hydrocarbon group, still more preferably a polycyclic cycloalkyl group, and a cyclohexane having three rings. An alkyl group is more preferable, a tricyclodecanyl group is particularly preferable, and a tricyclo [5.2.1.0 ^2,6 ] decanyl group is further particularly preferable.

  Examples of the structural unit (I-1) include structural units represented by the following formulas (1-1-1) to (1-1-9) (hereinafter referred to as “structural units (I-1a-1) to (I -1a-9) ") and the like. Examples of the structural unit (I-2) include structural units represented by the following formulas (1-2-1) and (1-2-2) (hereinafter referred to as “structural units (I-2a-1), (I -2a-2) "etc. Examples of the structural unit (I-3) include structural units represented by the following formulas (1-3-1) and (1-3-2) (hereinafter" structure "). Units (I-3-1) and (I-3-2) ”).

In the formulas (1-1-1) to (1-1-9), R ¹ has the same meaning as the formula (1-1).
As the structural unit (I), structural units (I-1) and (I-2) are preferred, and the structural units (I-1a-1) to (I-1a-9), (I-2a-1) and (I-2a-2) is more preferred, and structural units (I-1a-1), (I-1a-9) and (I-2a-1) are more preferred.

  [A] The lower limit of the content ratio of the structural unit (I) in the polymer component is preferably 5 mol%, more preferably 10 mol%, based on all structural units constituting the [A] polymer component, 20 More preferred is mol%, particularly preferred is 30 mol%, more particularly preferred is 35 mol%, and most preferred is 40 mol%. The upper limit of the content is preferably 95 mol%, more preferably 90 mol%, further preferably 80 mol%, particularly preferably 75 mol%, further particularly preferably 70 mol%, and most preferably 65 mol%.

  When the polymer component [A] is the polymer component [A1], the lower limit of the content ratio of the structural unit (I) is preferably 10 mol% with respect to all the structural units constituting the polymer (a). , 20 mol% is more preferable, 30 mol% is more preferable, and 40 mol% is particularly preferable. As an upper limit of the said content rate, 100 mol% is preferable, 90 mol% is more preferable, 80 mol% is further more preferable, 75 mol% is especially preferable.

  When the [A] polymer component is the [A2] polymer component, the lower limit of the content ratio of the structural unit (I) is preferably 5 mol% with respect to all the structural units constituting the polymer (c). 10 mol% is more preferable, 20 mol% is further more preferable, and 30 mol% is especially preferable. As an upper limit of the said content rate, 80 mol% is preferable, 75 mol% is more preferable, 70 mol% is further more preferable, 65 mol% is especially preferable.

  By making the content rate of structural unit (I) into the said range, the solubility to the developing solution of a [A] polymer component can be adjusted more appropriately, As a result, according to the said resist pattern formation method, The water repellency on the surface of the upper layer film and the suppression of development defects can both be enhanced.

[Structural unit (II)]
The structural unit (II) is a structural unit containing a fluorine atom other than the structural unit (I). That is, the structural unit having an alicyclic structure and containing a fluorine atom is included in the structural unit (I).

  Examples of the structural unit (II) include the structural unit (II-1) containing a group represented by the following formula (2), the structural unit (II-2) containing a fluorinated alkyl group, and the following formula (4). And a structural unit (II-3) containing the group to be formed.

(Structural unit (II-1))
The structural unit (II-1) is a structural unit containing a group represented by the following formula (2) (hereinafter also referred to as “group (2)”). [A] By having the structural unit (II-1), the polymer component can adjust water repellency and solubility in a developer more appropriately. As a result, the water repellency and defect suppression of the upper layer film surface can be further improved.

In said formula (2), ^RA is a hydrogen atom or a C1-C20 monovalent organic group. R ^B and R ^C are each independently a fluorine atom or a fluorinated alkyl group having 1 to 20 carbon atoms.

The monovalent organic group having 1 to 20 carbon atoms represented by ^RA is, for example, one in the bond of the group exemplified as the divalent organic group having 1 to 20 carbon atoms of L in the above formula (1). And a group formed by bonding the hydrogen atoms.

^RA is preferably a hydrogen atom from the viewpoint of adjusting the solubility in the developer to a more appropriate level and further improving the suppression of development defects.

The fluorinated alkyl group having 1 to 20 carbon atoms represented by R ^B and R ^C, for example fluoromethyl group, difluoromethyl group, difluoroethyl group, trifluoroethyl group, trifluoropropyl group, pentafluoropropyl group, A partially fluoro-substituted alkyl group such as a heptafluorobutyl group and a nonafluoropentyl group;
Examples thereof include perfluoroalkyl groups such as a trifluoromethyl group, a pentafluoroethyl group, a hexafluoropropyl group, a nonafluorobutyl group, and an undecafluoropentyl group. Among these, a perfluoroalkyl group is preferable and a trifluoromethyl group is more preferable.

  Examples of the group (2) include groups represented by the following formulas (2-1) to (2-8) (hereinafter also referred to as “groups (2-1) to (2-8)”). .

  As the group (2), a hydroxybis (perfluoroalkyl) methyl group is preferable, groups (2-1) to (2-3) are more preferable, and a group represented by the group (2-1) is more preferable.

  Examples of the structural unit (II-1) include a structural unit represented by the following formula (2-a) (hereinafter, also referred to as “structural unit (II-1a)”), and a structural unit (II-b). Structural units (hereinafter also referred to as “structural units (II-1b)”) and the like.

In said formula (2-a), ^RD is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ^E is a divalent linking group. R ^X is the group (2).
In the above formula (2-b), R ^Y is the group (2). R ^F is a single bond or a divalent linking group. R ^G is a hydrogen atom or a monovalent organic group.

^RD is preferably a hydrogen atom and a methyl group, more preferably a methyl group, from the viewpoint of copolymerization of the monomer that gives the structural unit (II-1a).

Examples of the divalent linking group represented by R ^E, for example, a divalent chain hydrocarbon group having 1 to 6 carbon atoms, a divalent alicyclic hydrocarbon group having 4 to 12 carbon atoms, said chain hydrocarbon Examples include a group containing a group between —O—, —S—, —CO—, —CS—, or a combination thereof, between carbon-carbon of a hydrogen group and an alicyclic hydrocarbon group.

Examples of the divalent chain hydrocarbon group having 1 to 6 carbon atoms include a methanediyl group, a 1,1-ethanediyl group, a 1,2-ethanediyl group, a 1,1-propanediyl group, and a 1,2-propanediyl group. 1,3-propanediyl group, 2,2-propanediyl group, 1,4-propanediyl group, 1,5-pentanediyl group, 1,6-hexanediyl group, 1-methyl-1,3-propanediyl Group, 2-methyl-1,3-propanediyl group, 2-methyl-1,2-propanediyl group, 1-methyl-1,4-butanediyl group, 2-methyl-1,4-butanediyl group, etc. Diyl group;
Alkenediyl groups such as 1,2-ethenediyl group, 1,3-propenediyl group, 1,2-propenediyl group;
Examples include alkynediyl groups such as 1,2-ethynediyl group and 1,3-propynediyl group.
Of these, alkanediyl groups are preferred, methanediyl groups, ethanediyl groups and propanediyl groups are more preferred, methanediyl groups, 1,1-ethanediyl groups, 1,2-ethanediyl groups, 1,2-propanediyl groups and 1 1,3-propanediyl group is more preferable, and 1,2-propanediyl group is particularly preferable.

Examples of the divalent alicyclic hydrocarbon group having 4 to 12 carbon atoms include cyclobutanediyl groups such as 1,3-cyclobutanediyl groups, cyclopentanediyl groups such as 1,3-cyclopentanediyl groups, 1,4 -Cyclohexanediyl group such as cyclohexanediyl group, 1,2-cyclohexanediyl group, cyclooctanediyl group such as 1,5-cyclooctanediyl group, 1,1-cyclopentylethanediyl group, 1,2-cyclopentylethanediyl group A monocyclic cycloalkanediyl group such as a cyclohexylethanediyl group such as a cyclopentylethanediyl group such as 1,1-cyclohexylethanediyl group, 1,2-cyclohexylethanediyl group;
1,4-norbornanediyl group, norbornanediyl group such as 2,5-norbornanediyl group, 1,3-adamantanediyl group, adamantanediyl group such as 2,4-adamantanediyl group, 2,7-tetracyclododecanediyl And a polycyclocycloalkanediyl group such as a tetracyclododecanediyl group, a norbornylmethanediyl group, an adamantylmethanediyl group, and the like.
Among these, norbornanediyl group, tetracyclododecanediyl group and cyclohexylethanediyl group are preferable, and 2,5-norbornanediyl group, 2,7-tetracyclododecanediyl group and 1,2-cyclohexylethanediyl group are more preferable. A 1,2-cyclohexylethanediyl group is more preferable.

  As the structural unit (II-1a), for example, structural units represented by the following formulas (2-a-1) to (2-a-5) (hereinafter referred to as “structural units (II-1a-1) to (II)”) -1a-5) ") and the like.

In the above formulas (2-a-1) to (2-a-5), R ^A has the same meaning as the above formula (2). ^RD is synonymous with the formula (2-a).

Examples of the divalent linking group represented by R ^F include a divalent chain hydrocarbon group having 1 to 20 carbon atoms, a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, and the above chain carbon group. Examples include a group in which one or more of a hydrogen group and an alicyclic hydrocarbon group are combined with -O-.

  Examples of the divalent chain hydrocarbon group having 1 to 20 carbon atoms include methanediyl group, ethanediyl group, propanediyl group, butanediyl group, pentanediyl group, hexanediyl group, octanediyl group, decandidiyl group, dodecanediyl group, and tetradecandiyl group. Group, hexadecandiyl group, octadecandiyl group, icosanediyl group and the like.

  Examples of the divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include a cyclopropanediyl group, a cyclobutanediyl group, a cyclopentanediyl group, a cyclohexanediyl group, a cyclooctanediyl group, and a cyclodecandidiyl group.

  Examples of the group in which one or more of a chain hydrocarbon group and an alicyclic hydrocarbon group are combined with -O- include, for example, a methanediyloxy group, an ethanediyloxy group, a propanediyloxy group, and butane. Alkanediyloxy groups such as diyloxy group, pentanediyloxy group, hexanediyloxy group, octanediyloxy group; methanediyloxymethanediyl group, methanediyloxyethanediyl group, methanediyloxy (1,2-propanediyl) A group containing one —O— such as a group, a methanediyloxybutanediyl group, a methanediyloxycyclohexanediyl group; a group containing two or more —O— such as a propanediyloxyethanediyloxyethanediyl group, etc. Can be mentioned.

Among these, R ^F is preferably a single bond, a methanediyl group, an alkanediyloxy group having 2 to 4 carbon atoms, or a cycloalkanediyloxy group having 7 to 10 carbon atoms. -Ethanediyloxy group, 1,2-propanediyloxy group and 2,6-norbornanediyloxy group are more preferable, and 1,2-ethanediyloxy group is more preferable.

Examples of the monovalent organic group represented by ^RG include a monovalent chain hydrocarbon group having 1 to 20 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, and 6 to 6 carbon atoms. 20 monovalent aromatic hydrocarbon groups or one or more of them and a linking group containing a heteroatom such as -O-, -CO-, -OCO-, -COO-, -S- And a combination of these and the like. Some or all of the hydrogen atoms of these groups may be substituted with a fluorine atom, a hydroxy group, a carboxy group, an amino group, a cyano group, or the like.

R ^G includes a hydrogen atom, a monovalent chain hydrocarbon group, a monovalent alicyclic hydrocarbon group, a monovalent fluorinated chain hydrocarbon group, a monovalent fluorinated alicyclic hydrocarbon group, A monovalent hydroxy chain hydrocarbon group, a group containing a hydroxybis (perfluoroalkyl) methyl group and a group having a monovalent lactone structure are preferred, and a hydrogen atom, a methyl group, an ethyl group, an i-propyl group, an n- Butyl group, cyclohexylmethyl group, hexafluoro-2-propyl group, 2-hydroxyethyl group, hydroxybis (perfluoroalkyl) butyl group, hydroxybis (perfluoroalkyl) methylnorbornyl group, α-butyrolactone-yl group Norbornanelactone-yl group and trifluoromethylnorbornanelactone-yl group are more preferable, and methyl group and ethyl group are more preferable. .

  As the structural unit (II-1b), for example, structural units represented by the following formulas (2-b-1) to (2-b-13) (hereinafter referred to as “structural units (II-1b-1) to (II)”) -1b-13) ") and the like.

In the above formulas (2-b-1) to (2-b-13), R ^A has the same meaning as the above formula (2).

  Among these, the structural units (II-1b-1) to (II-1b-9), the structural unit (II-1b-13) and the structural unit (II-1b-16) are preferable, and the structural unit (II- 1b-1) and the structural unit (II-1b-2) are more preferable.

  [A] The lower limit of the content ratio of the structural unit (II-1) in the polymer component is preferably 10 mol%, more preferably 20 mol% with respect to all the structural units constituting the [A] polymer component. 35 mol% is more preferable, and 45 mol% is particularly preferable. As an upper limit of the said content rate, 90 mol% is preferable, 80 mol% is more preferable, 75 mol% is further more preferable, 60 mol% is especially preferable.

  When the [A] polymer component is the [A1] polymer component, the lower limit of the content ratio of the structural unit (II-1) is 10 mol% with respect to all the structural units constituting the polymer (b). Is preferable, 20 mol% is more preferable, 30 mol% is further more preferable, and 40 mol% is especially preferable. As an upper limit of the said content rate, 100 mol% is preferable, 90 mol% is more preferable, 80 mol% is further more preferable, 75 mol% is especially preferable.

  [A] When the polymer component is the [A2] polymer component, the lower limit of the content ratio of the structural unit (II-1) is 5 mol% with respect to all the structural units constituting the polymer (c). Is preferable, 10 mol% is more preferable, 20 mol% is further more preferable, and 30 mol% is especially preferable. As an upper limit of the said content rate, 80 mol% is preferable, 75 mol% is more preferable, 70 mol% is further more preferable, 65 mol% is especially preferable.

  By making the content rate of structural unit (II-1) into the said range, both the water repellency and defect inhibitory property of the upper film surface can be improved further.

(Structural unit (II-2))
The structural unit (II-2) is a structural unit containing a fluorinated alkyl group. [A] Since the polymer component has the structural unit (II-2), the water repellency of the upper layer film can be further increased.

  Examples of the fluorinated alkyl group include a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a fluoroethyl group, a difluoroethyl group, a trifluoroethyl group, a pentafluoroethyl group, a fluoro-n-propyl group, and a difluoro-n-. Propyl group, trifluoro-n-propyl group, pentafluoro-n-propyl group, heptafluoro-n-propyl group, fluoro-i-propyl group, trifluoro-i-propyl group, hexafluoro-i-propyl group, Examples include a fluoro-n-butyl group, an octafluoro-n-butyl group, a nonafluoro-n-butyl group, an undecafluoro-n-pentyl group, and a heptadecafluoro-n-decyl group.

  As the structural unit (II-2), from the viewpoint of copolymerization of the monomer that gives the structural unit (II-2), a structural unit represented by the following formula (3) (hereinafter, “structural unit (II- 2a) ") is preferred.

In said formula (3), ^RH is a hydrogen atom, a methyl group, a fluorine atom, or a trifluoromethyl group. R ^I is a monovalent fluorinated alkyl group.

As said ^RH , a hydrogen atom and a methyl group are preferable and a methyl group is more preferable from a viewpoint of the copolymerizability of the monomer which gives a structural unit (I-2a).

Examples of the monovalent fluorinated alkyl group represented by R ^I include the groups exemplified as the above-described fluorinated alkyl group.

  Examples of the structural unit (II-2a) include structural units represented by the following formulas (3-1) to (3-6) (hereinafter referred to as “structural units (II-2a-1) to (II-2a-6)”. ) ")) And the like.

In the above formulas (3-1) to (3-6), ^RH is synonymous with the above formula (3).

  [A] The lower limit of the content ratio of the structural unit (II-2) in the polymer component is preferably 10 mol%, more preferably 20 mol%, based on all structural units constituting the [A] polymer component. 30 mol% is more preferable. As an upper limit of the said content rate, 80 mol is preferable, 70 mol% is more preferable, and 60 mol% is further more preferable.

  [A] When the polymer component is the [A1] polymer component, the lower limit of the content ratio of the structural unit (II-2) is 20 mol% with respect to all the structural units constituting the polymer (b). Is preferable, 40 mol% is more preferable, and 60 mol% is further more preferable. As an upper limit of the said content rate, 100 mol% is preferable, 90 mol% is more preferable, and 80 mol% is further more preferable.

  When the [A] polymer component is the [A2] polymer component, the lower limit of the content ratio of the structural unit (II-2) is 10 mol% with respect to all the structural units constituting the polymer (c). Is preferable, 20 mol% is more preferable, and 30 mol% is further more preferable. As an upper limit of the said content rate, 80 mol% is preferable, 70 mol% is more preferable, and 60 mol% is further more preferable.

  By making the content rate of structural unit (II-2) into the said range, the water repellency of the surface of an upper layer film | membrane can further be improved.

(Structural unit (II-3))
The structural unit (II-3) is a structural unit containing the group (4). The group (4) is a fluorinated sulfonamide group represented by the following formula (4). [A] A polymer component can improve the solubility to the developing solution containing an organic solvent by having structural unit (II-3). As a result, the water repellency and defect suppression of the upper layer film surface can both be enhanced.

In the formula (4), ^{R 3} is a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms.

Examples of the monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by R ³ include the same groups as the fluorinated hydrocarbon group exemplified as R ¹ above.

Examples of the group (4) include a fluoromethylsulfonamide group, a difluoromethylsulfonamide group, a trifluoromethylsulfonamide group, a difluoroethylsulfonamide group, a trifluoroethylsulfonamide group, a pentafluoroethylsulfonamide group, and a trifluoro- n-propylsulfonamide group, heptafluoro-n-sulfonamide group, trifluoro-i-propylsulfonamide group, hexafluoro-i-propylsulfonamide group, nonafluoro-n-butylsulfonamide group, undecafluoro-n -A pentyl sulfonamide group etc. are mentioned.
Among these, a perfluoroalkylsulfonamide group is preferable, a trifluoromethylsulfonamide group, a pentafluoroethylsulfonamide group, a trifluoro-n-propylsulfonamide group, and a nonafluoro-n-butylsulfonamide group are more preferable, A trifluoromethylsulfonamide group is more preferred.

  Examples of the structural unit (II-3) include a structural unit represented by the following formula (4-a) (hereinafter also referred to as “structural unit (II-3a)”).

In the above formula (4-a), R ^J represents a hydrogen atom, a methyl group, a fluorine atom or a trifluoromethyl group. ^RK is a divalent linking group. R ³ has the same meaning as the above formula (4).

R ^J is preferably a hydrogen atom or a methyl group, more preferably a methyl group, from the viewpoint of copolymerization of the monomer that gives the structural unit (II-3a).

Examples of the divalent linking group represented by R ^K, for example, a divalent chain hydrocarbon group having 1 to 6 carbon atoms, a divalent alicyclic hydrocarbon group having 4 to 12 carbon atoms, 6 carbon atoms 14 divalent aromatic hydrocarbon group, a group in which the chain hydrocarbon group and —O— are combined, and a hydrogen atom in the group in which the chain hydrocarbon group and —O— are combined is an oxo group. Examples include substituted groups.

Examples of the divalent chain hydrocarbon group having 1 to 6 carbon atoms include a methanediyl group, a 1,2-ethanediyl group, a 1,1-ethanediyl group, a 1,3-propanediyl group, and a 1,2-propanediyl group. 1,1-propanediyl group, 2,2-propanediyl group, 1,4-propanediyl group, 1,5-pentanediyl group, 1,6-hexanediyl group, 1-methyl-1,3-propanediyl Group, 2-methyl-1,3-propanediyl group, 2-methyl-1,2-propanediyl group, 1-methyl-1,4-butanediyl group, 2-methyl-1,4-butanediyl group, etc. Diyl group;
Examples include alkenediyl groups such as 1,2-ethenediyl group, 1,3-propenediyl group, and 1,2-propenediyl group.

Examples of the divalent alicyclic hydrocarbon group having 4 to 12 carbon atoms include a cyclobutanediyl group such as 1,3-cyclobutanediyl group; a cyclopentanediyl group such as 1,3-cyclopentanediyl group; -Cyclohexanediyl group such as cyclohexanediyl group, 1,2-cyclohexanediyl group; monocyclic cycloalkanediyl group such as cyclooctanediyl group such as 1,5-cyclooctanediyl group;
1,4-norbornanediyl group, norbornanediyl group such as 2,5-norbornanediyl group, polycyclic alkanediyl group such as adamantanediyl group such as 1,3-adamantanediyl group, 2,4-adamantanediyl group, etc. Can be mentioned.

Examples of the divalent aromatic hydrocarbon group having 6 to 14 carbon atoms include arenediyl groups such as benzenediyl group, toluenediyl group, naphthalenediyl group;
Arenediylalkanediyl groups such as benzenediylmethanediyl group, naphthalenediylmethanediyl group;
Examples include alkanediylarenediylalkanediyl groups such as methanediylbenzenediylmethanediyl group and methanediylnaphthalenediylmethanediyl group.

  Examples of the group obtained by combining a chain hydrocarbon group and —O— include ethanediyloxy, ethanediyl group, and propanediyloxypropanediyl group.

  Examples of the group obtained by substituting a hydrogen atom of a group in which a chain hydrocarbon group and —O— are combined with an oxo group include a methanediylcarbonylmethanediylcarbonyloxyethanediyl group and an ethanediylcarbonylmethanediylcarbonyloxypropanediyl group. Etc.

The R ^K, among these, a divalent chain hydrocarbon group, an aromatic divalent alicyclic hydrocarbon group and C6-10 C5-8 1 to 3 carbon atoms carbide A hydrogen group is preferable, 1,2-ethanediyl group, 1,3-propanediyl group, 1,6-cyclohexanediyl group and methanediylbenzenediylmethanediyl group are more preferable, and 1,2-ethanediyl group is more preferable.

  As the structural unit (II-3a), for example, structural units represented by the following formulas (4-a-1) to (4-a-7) (hereinafter referred to as “structural units (II-3a-1) to (II) -3a-7) ”) and the like.

In the above formulas (4-a-1) to (4-a-7), R ^J has the same meaning as the above formula (4-a).

  Among these, the structural units (II-3a-1) to (II-3a-4) are preferable, the structural units (II-3a-1) to (II-3a-3) are more preferable, and the structural unit (II -3a-1) is more preferred.

  [A] The lower limit of the content ratio of the structural unit (II-3) in the polymer component is preferably 5 mol% and more preferably 10 mol% with respect to all the structural units constituting the [A] polymer component. . As an upper limit of the said content rate, 90 mol% is preferable and 70 mol% is more preferable.

  When the [A] polymer component is the [A1] polymer component, the lower limit of the content ratio of the structural unit (II-3) is 10 mol% with respect to all the structural units constituting the polymer (b). Is preferable, and 20 mol% is more preferable. As an upper limit of the said content rate, 60 mol% is preferable and 50 mol% is more preferable.

  [A2] The lower limit of the content ratio of the structural unit (II-3) in the polymer component is preferably 5 mol% and more preferably 10 mol% with respect to all the structural units constituting the polymer (c). As an upper limit of the said content rate, 90 mol% is preferable and 70 mol% is more preferable.

  By making the content rate of structural unit (II-3) into the said range, according to the said negative resist pattern formation method, both the water repellency and development defect inhibitory property of an upper layer film surface can be improved further.

(Structural units containing other fluorine atoms)
[A] The polymer component may have a structural unit containing a fluorine atom other than the structural units (II-1) to (II-3) as the structural unit (II). Examples of the structural unit containing another fluorine atom include a structural unit containing a fluorinated aromatic hydrocarbon group. As an upper limit of the content rate of the structural unit containing another fluorine atom, 20 mol% is preferable with respect to all the structural units which comprise a [A] polymer component, and 10 mol% is more preferable.

  [A] The lower limit of the content ratio of the structural unit (II) in the polymer component is preferably 5 mol%, more preferably 10 mol%, based on all structural units constituting the [A] polymer component, 15 More preferred is mol%, and particularly preferred is 20 mol%. As an upper limit of the said content rate, 70 mol% is preferable, 60 mol% is more preferable, 50 mol% is further more preferable, 40 mol% is especially preferable.

  [A] When the polymer component is the [A1] polymer component, the lower limit of the content ratio of the structural unit (II) is preferably 10 mol% with respect to all the structural units constituting the polymer (b). , 20 mol% is more preferable, 30 mol% is more preferable, and 40 mol% is particularly preferable. As an upper limit of the said content rate, 100 mol% is preferable, 90 mol% is more preferable, 80 mol% is further more preferable, 70 mol% is especially preferable.

  [A] When the polymer component is the [A2] polymer component, the lower limit of the content ratio of the structural unit (II) is preferably 5 mol% with respect to all the structural units constituting the polymer (c). 10 mol% is more preferable, 15 mol% is further more preferable, and 20 mol% is especially preferable. As an upper limit of the said content rate, 70 mol% is preferable, 60 mol% is more preferable, 50 mol% is further more preferable, 40 mol% is especially preferable.

  By making the content rate of structural unit (II) into the said range, according to the said negative resist pattern formation method, both the water repellency of the upper film surface and development defect inhibitory property can be improved further.

[Other structural units]
Examples of other structural units include a structural unit (III) containing a carboxy group, a sulfo group or a combination thereof, a structural unit (IV) containing a group represented by the following formula (8), and a structural unit containing a basic group And a structural unit (V) containing a group that generates a basic group by the action of an acid, a lactone structure, a cyclic carbonate structure, a sultone structure, or a structural unit (VI) containing a combination thereof.

(Structural unit (III))
The structural unit (III) is a structural unit containing a carboxy group, a sulfo group, or a combination thereof.

  Examples of the structural unit containing a carboxy group (hereinafter also referred to as “structural unit (III-1)”) include structural units represented by the following formulas (5-1) to (5-3) (hereinafter referred to as “structural units”). (III-1-1) to (III-1-3) "and the like.

In the above formulas (5-1) to (5-3), R ″ represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.
In the above formulas (5-1) and (5-2), R ^c1 and R ^c2 each independently represent a linear or branched divalent hydrocarbon group having 1 to 6 carbon atoms, or 4 carbon atoms. Or a divalent alicyclic hydrocarbon group having 12 to 12 carbon atoms or a divalent aromatic hydrocarbon group having 6 to 12 carbon atoms.

C 1-6 linear or branched divalent hydrocarbon group represented by R ^c1 and R ^c2 , C 4-12 divalent alicyclic hydrocarbon group, and C 6-6 Examples of the divalent aromatic hydrocarbon group of 12 include the same as those of L ² in formula (6) described later.

  As the structural unit (III-1-1), for example, the structural unit represented by the following formulas (5-1-1) and (5-1-2) may be used as the structural unit (III-1-2): The structural unit represented by the following formula (5-1-3) is represented by the following formulas (5-2-1) and (5-2-2) as the structural unit (III-1-3). Each structural unit may be mentioned.

  In the above formulas (5-1-1) to (5-2-2), R ″ has the same meaning as the above formulas (5-1) to (5-3).

  Examples of the structural unit containing a sulfo group (hereinafter, also referred to as “structural unit (III-2)”) include a structural unit represented by the following formula (6).

In the above formula (6), R ^W is a hydrogen atom, a methyl group, a fluorine atom or a trifluoromethyl group. L ² is a single bond, an oxygen atom, a sulfur atom, a divalent linear or branched hydrocarbon group having 1 to 6 carbon atoms, a divalent alicyclic hydrocarbon group having 4 to 12 carbon atoms, carbon number 6-12 divalent aromatic hydrocarbon group or ^{-C (= O) -X-R} a - a group. X is an oxygen atom, a sulfur atom or an NH group. R ^a is a single bond, a divalent linear or branched hydrocarbon group having 1 to 6 carbon atoms, ^a divalent alicyclic hydrocarbon group having 4 to 12 carbon atoms, or 2 having 6 to 12 carbon atoms. Valent aromatic hydrocarbon group.

Examples of the divalent linear or branched hydrocarbon group having 1 to 6 carbon atoms represented by L ² and R ^a, is preferably a saturated hydrocarbon group such as methylene group, ethylene group, 1,3 Propylene group, 1,2-propylene group, 1,1-propylene group, 2,2-propylene group, tetramethylene group, pentamethylene group, hexamethylene group, 1-methyl-1,3-propylene group, 2-methyl Examples include -1,3-propylene group, 2-methyl-1,2-propylene group, 1-methyl-1,4-butylene group, 2-methyl-1,4-butylene group and the like.

Examples of the divalent alicyclic hydrocarbon group having 4 to 12 carbon atoms represented by L ² and R ^a, may be either monocyclic or polycyclic, in the polycyclic have a crosslinked structure Good. Examples of the monocyclic hydrocarbon group include cyclobutylene groups such as 1,3-cyclobutylene groups, cyclopentylene groups such as 1,3-cyclopentylene groups, and cyclohexylene groups such as 1,4-cyclohexylene groups. Group, a cyclooctylene group such as a 1,5-cyclooctylene group, and the like. Examples of the polycyclic hydrocarbon group include a hydrocarbon group having a 2- to 4-membered ring, a norbornylene group such as a 1,4-norbornylene group and a 2,5-norbornylene group, and a 1,5-adamantylene group. And adamantylene groups such as 2,6-adamantylene group.

Examples of the divalent aromatic hydrocarbon group having 6 to 12 carbon atoms represented by L ² and R ^a, for example, a phenylene group, such as an arylene group such as a tolylene group. In addition, the alicyclic hydrocarbon group and the aromatic hydrocarbon group do not need to be constituted only by a ring structure, and a part thereof may include a chain structure.

L ² is a single bond, a divalent linear or branched hydrocarbon group having 1 to 6 carbon atoms, ^a divalent aromatic hydrocarbon having 6 to 12 carbon atoms, or ^Ra has 1 to 6 carbon atoms. divalent ^{-C (= O) -NH-R} a is preferably a straight-chain or branched hydrocarbon group, a single bond, a methylene group, a phenylene group, -C (= O) -NH- C ( CH ₃ ) ₂ —CH ₂ — is more preferred.

  Examples of the structural unit (III-2) include structural units represented by the following formulas (6-1) to (6-4).

In the above formula (6-1) ~ (6-4), ^{R W} is as defined in the above formula (6).

  As the structural unit (III), the structural unit (III-1) is preferable from the viewpoint that the solubility of the [A] polymer component in the developer can be adjusted more appropriately.

  [A] When the polymer component has the structural unit (III), the lower limit of the content ratio of the structural unit (III) is preferably 5 mol% with respect to all the structural units constituting the [A] polymer component. 10 mol% is more preferable, 15 mol% is further more preferable, and 20 mol% is especially preferable. As an upper limit of the said content rate, 70 mol% is preferable, 60 mol% is more preferable, 50 mol% is further more preferable, 40 mol% is especially preferable.

  [A] When the polymer component is the [A1] polymer component, the lower limit of the content ratio of the structural unit (III) is preferably 5 mol% with respect to all the structural units constituting the polymer (a). 10 mol% is more preferable, 15 mol% is further more preferable, and 20 mol% is especially preferable. As an upper limit of the said content rate, 50 mol% is preferable, 40 mol% is more preferable, 30 mol% is further more preferable, 25 mol% is especially preferable. Moreover, as a minimum of the content rate of structural unit (III), 5 mol% is preferable with respect to all the structural units which comprise a polymer (b), 10 mol% is more preferable, 15 mol% is further more preferable, 20 mol% is particularly preferred. As an upper limit of the said content rate, 50 mol% is preferable, 40 mol% is more preferable, 30 mol% is further more preferable, 25 mol% is especially preferable.

  [A] When the polymer component is the [A2] polymer component, the lower limit of the content ratio of the structural unit (III) is preferably 5 mol% with respect to all the structural units constituting the polymer (c). 10 mol% is more preferable, 15 mol% is further more preferable, and 20 mol% is especially preferable. As an upper limit of the said content rate, 50 mol% is preferable, 40 mol% is more preferable, 30 mol% is further more preferable, 25 mol% is especially preferable.

(Structural unit (IV))
The structural unit (IV) is a structural unit containing a group represented by the following formula (7) (hereinafter also referred to as “group (7)”). The composition (I) for forming the upper layer film can form a resist pattern with fewer development defects because the [A] polymer component has the structural unit (IV).

In the above formula (7), R ⁴ is a hydrogen atom, a halogen atom, a nitro group, an alkyl group, a monovalent alicyclic hydrocarbon group, an alkoxy group, an acyl group, an aralkyl group or an aryl group. Some or all of the hydrogen atoms of the alkyl group, alicyclic hydrocarbon group, alkoxy group, acyl group, aralkyl group and aryl group may be substituted. R ⁵ is —C (═O) —R ⁶ , —S (═O) ₂ —R ⁷ , —R ⁸ —CN or —R ⁹ —NO ₂ . R ⁶ and R ⁷ are each independently a hydrogen atom, alkyl group, fluorinated alkyl group, monovalent alicyclic hydrocarbon group, alkoxy group, cyano group, cyanomethyl group, aralkyl group or aryl group. However, R ⁶ or R ⁷ and R ⁴ may be bonded to each other to form a ring structure. R ⁸ and R ⁹ are each independently a single bond, a methylene group or an alkylene group having 2 to 5 carbon atoms.

Examples of the halogen atom represented by R ⁴ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Among these, a fluorine atom and a chlorine atom are preferable.

Examples of the alkyl group represented by R ⁴ include linear alkyl groups such as a methyl group, an ethyl group, an n-propyl group, and an n-butyl group; an i-propyl group, an i-butyl group, and a sec-butyl group. And a branched alkyl group such as t-butyl group. As an alkyl group, a C1-C20 alkyl group is preferable.

Examples of the monovalent alicyclic hydrocarbon group represented by R ⁴ include monocyclic alicyclic hydrocarbon groups such as a cyclopentyl group and a cyclohexyl group; and many examples such as an adamantyl group, a norbornyl group, and a tetracyclodecanyl group. And ring alicyclic hydrocarbon groups. As an alicyclic hydrocarbon group, a C3-C20 alicyclic hydrocarbon group is preferable.

Examples of the alkoxy group represented by R ⁴ include a methoxy group and an ethoxy group. As an alkoxy group, a C1-C20 alkoxy group is preferable.

Examples of the acyl group represented by R ⁴ include an acetyl group and a propionyl group. As the acyl group, an acyl group having 2 to 20 carbon atoms is preferable.

Examples of the aralkyl group represented by R ⁴ include a benzyl group, a phenethyl group, and a naphthylmethyl group. As the aralkyl group, an aralkyl group having 7 to 12 carbon atoms is preferable.

Examples of the aryl group represented by R ⁴ include a phenyl group, a tolyl group, a dimethylphenyl group, a 2,4,6-trimethylphenyl group, and a naphthyl group. As the aryl group, an aryl group having 6 to 10 carbon atoms is preferable.

Examples of the substituent that the alkyl group, monovalent alicyclic hydrocarbon group, alkoxy group, acyl group, aralkyl group and aryl group represented by R ⁴ may have include a fluorine atom and a chlorine atom. A halogen atom, a hydroxyl group, a nitro group, a cyano group, etc. are mentioned.

As R ⁴ , among these, from the viewpoint of balancing the developer solubility and the peel resistance of the upper layer film formed from the upper layer film-forming composition (I), among them, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, A C1-C5 alkoxy group and a C2-C5 acyl group are preferable, and a hydrogen atom, a methyl group, an ethyl group, and an acetyl group are more preferable.

When R ⁵ is —C (═O) —R ⁶ and —S (═O) ₂ —R ⁷ , an alkyl group represented by R ⁶ and R ⁷ , a monovalent alicyclic hydrocarbon group, an alkoxy group Examples of the aralkyl group and aryl group include the same groups as those exemplified as the respective groups for R ⁴ . Examples of the fluorinated alkyl group represented by R ⁶ and R ⁷ include groups in which at least one of the hydrogen atoms exemplified as the alkyl group for R ⁴ is substituted with a fluorine atom. Among these, as R ⁶ and R ⁷ , a hydrogen atom and an alkyl group are preferable, and a hydrogen atom, a methyl group, and an ethyl group are more preferable.

The group containing a ring structure formed by bonding R ⁶ or R ⁷ and R ⁴ to each other contains a carbon atom to which R ⁶ or R ⁷ and R ⁴ are bonded, and has 5 carbon atoms having an oxo group. ~ 12 divalent alicyclic hydrocarbon groups are preferred.

When R ⁵ is —R ⁸ —CN and —R ⁹ —NO ₂ , R ⁸ and R ⁹ are preferably a single bond, a methanediyl group or an ethanediyl group.

  As the group (7), groups represented by the following formulas (7-1) to (7-8) (hereinafter also referred to as “groups (7-1) to (7-8)”) are preferable.

  In the above formulas (7-1) to (7-8), * represents a binding site.

  Examples of the structural unit (IV) include a structural unit derived from a (meth) acrylic acid ester derivative having a group (7), a (meth) acrylamide derivative, a vinyl ether derivative, an olefin derivative, and a styrene derivative. In this, the structural unit derived from the (meth) acrylic acid ester derivative which has group (7) from a copolymerizable viewpoint of the monomer which gives structural unit (III) is preferable. That is, as the structural unit (IV), a structural unit represented by the following formula (7-a) (hereinafter also referred to as “structural unit (IV-a)”) is preferable.

In the above formula (7-a), R ^S represents a hydrogen atom, a methyl group, a fluorine atom or a trifluoromethyl group. R ^T is a (m + 1) -valent linking group. R ⁴ and R ⁵ are as defined in the above formula (7). m is an integer of 1-3. When R ⁴ and R ⁵ is plural, respectively, it may be different in each of a plurality of R ⁴ and R ⁵ are the same.

As ^RS , a hydrogen atom and a methyl group are preferable, and a methyl group is more preferable, from the viewpoint of copolymerization of the monomer that gives the structural unit (7-a).

As the (m + 1) -valent linking group represented by ^RT , for example, as a divalent linking group (when n is 1), an alkanediyl group, a divalent alicyclic hydrocarbon group, an alkenediyl group, an arenediyl group Groups and the like. Note that some or all of the hydrogen atoms contained in these groups may be substituted with a halogen atom such as a fluorine atom or a chlorine atom, a cyano group, or the like.

  Examples of the alkanediyl group include a methanediyl group, an ethanediyl group, a propanediyl group, a butanediyl group, a hexanediyl group, and an octanediyl group. As the alkanediyl group, an alkanediyl group having 1 to 8 carbon atoms is preferable.

  Examples of the divalent alicyclic hydrocarbon group include monocyclic alicyclic hydrocarbon groups such as cyclopentanediyl group and cyclohexanediyl group; polycyclic alicyclic hydrocarbons such as norbornanediyl group and adamantanediyl group Etc. As a bivalent alicyclic hydrocarbon group, a C5-C12 alicyclic hydrocarbon group is preferable.

  Examples of the alkenediyl group include an ethenediyl group, a propenediyl group, and a butenediyl group. The alkenediyl group is preferably an alkenediyl group having 2 to 6 carbon atoms.

  Examples of the arenediyl group include a phenylene group, a tolylene group, and a naphthylene group. As the arenediyl group, an arenediyl group having 6 to 15 carbon atoms is preferable.

Among these, as ^RT , an alkanediyl group, a divalent alicyclic hydrocarbon group is preferable, an alkanediyl group having 1 to 4 carbon atoms, and a divalent alicyclic hydrocarbon group having 6 to 11 carbon atoms. Is more preferable. When ^RT is a divalent alicyclic hydrocarbon group, it is preferable from the viewpoint of improving the water repellency of the resulting upper layer film.

  As the structural unit (IV-a), structural units represented by the following formulas (7-a-1) to (7-a-8) (hereinafter referred to as “structural units (IV-a-1) to (IV-a)”). −8) ”) is preferred.

In the above formulas (7-a-1) to (7-a-8), R ^S has the same meaning as the above formula (7-a).

  [A] When the polymer component has a structural unit (IV), the lower limit of the content ratio of the structural unit (IV) is preferably 5 mol% with respect to all the structural units constituting the [A] polymer component. 10 mol% is more preferable, 15 mol% is further more preferable, and 20 mol% is especially preferable. As an upper limit of the said content rate, 70 mol% is preferable, 60 mol% is more preferable, 50 mol% is further more preferable, 40 mol% is especially preferable.

  [A] When the polymer component is the [A1] polymer component, the lower limit of the content ratio of the structural unit (IV) is preferably 5 mol% with respect to all the structural units constituting the polymer (a). 10 mol% is more preferable, 15 mol% is further more preferable, and 20 mol% is especially preferable. As an upper limit of the said content rate, 50 mol% is preferable, 40 mol% is more preferable, 30 mol% is further more preferable, 25 mol% is especially preferable. Moreover, as a minimum of the said content rate, 5 mol% is preferable with respect to all the structural units which comprise a polymer (b), 10 mol% is more preferable, 15 mol% is further more preferable, and 20 mol% is especially preferable. preferable. As an upper limit of the said content rate, 50 mol% is preferable, 40 mol% is more preferable, 30 mol% is further more preferable, 25 mol% is especially preferable.

  [A] When the polymer component is the [A2] polymer component, the lower limit of the content ratio of the structural unit (IV) is preferably 5 mol% with respect to all the structural units constituting the polymer (c). 10 mol% is more preferable, 15 mol% is further more preferable, and 20 mol% is especially preferable. As an upper limit of the said content rate, 50 mol% is preferable, 40 mol% is more preferable, 30 mol% is further more preferable, 25 mol% is especially preferable.

  By making the content rate of structural unit (IV) into the said range, a resist pattern with few development defects can be formed.

(Structural unit (V))
The structural unit (V) is a structural unit containing a basic group, a structural unit containing a group that generates a basic group by the action of an acid, or a combination thereof. [A] Since the polymer component has the structural unit (V), deprotection (generation of acidic groups due to dissociation of acid dissociable groups) is suppressed by the action of the basic group, and as a result, exposure of the resist film The film loss can be suppressed at the portion.

  The basic group is not particularly limited as long as it is a basic group, and examples thereof include an amino group, a monohydrocarbon group-substituted amino group, a dihydrocarbon group-substituted amino group, a cyclic amino group, and an amide group.

Examples of the monohydrocarbon group-substituted amino group include monoalkylamino groups such as a methylamino group, an ethylamino group, and a propylamino group;
A monocycloalkylamino group such as a cyclopentylamino group and a cyclohexylamino group;
Monoarylamino groups such as a phenylamino group and a naphthylamino group;
Examples thereof include monoaralkylamino groups such as benzylamino group and phenethylamino group.

Examples of the dihydrocarbon group-substituted amino group include dialkylamino groups such as dimethylamino group, methylethylamino group, diethylamino group and dipropylamino group;
A dicycloalkylamino group such as a dicyclopentylamino group, a dicyclohexylamino group, a dinorbornylamino group;
Diarylamino groups such as diphenylamino group, ditolylamino group, dinaphthylamino group, phenyltolylamino group;
Examples thereof include diaralkylamino groups such as dibenzylamino group, diphenethylamino group, and di (naphthylmethyl) amino group.

  Examples of the cyclic amino group include an azacyclopentyl group (pyrrolidinyl group), an azacyclohexyl group (piperidinyl group), an azacyclooctyl group, and the like.

  Examples of the amide group include a dimethylamide group and a diethylamide group.

  Of these, the basic group is preferably a dihydrocarbon group-substituted amino group, more preferably a dialkylamino group, and even more preferably a dimethylamino group.

  Examples of the group that generates a basic group by the action of an acid include a group obtained by substituting a hydrogen atom of the above basic group with an alkoxycarbonyl group. As the group that generates basicity by the action of an acid, a t-alkoxycarbonylmonohydrocarbon group-substituted amino group and a t-alkoxycarbonyl-substituted cyclic amino group are preferable, a t-alkoxycarbonyl-substituted cyclic amino group is more preferable, and Nt -Alkoxycarbonyl azacycloalkyl group is more preferable, and Nt-butoxycarbonyl azacyclohexyl group is particularly preferable.

  Examples of the structural unit (V) include a structural unit represented by the following formula (8) (hereinafter also referred to as “structural unit (Va)”).

In said formula (8), ^RU is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ^V is a group containing a group containing a basic group or a group that generates a basic group by the action of an acid.

The R ^U, from the viewpoint of copolymerizability of the monomer giving the structural unit (IV), preferably a hydrogen atom or a methyl group, more preferably a methyl group.

The group containing a group resulting a basic group by the action of radicals and an acid containing a basic group represented by R ^V, for example, groups formed basic groups by the action of the aforementioned basic group and an acid is bonded 1 Valent hydrocarbon group and the like. Among these, a dihydrocarbon group-substituted amino hydrocarbon group and an Nt-alkoxycarbonyl-substituted cyclic amino group are preferable, a dialkylaminoalkyl group and an Nt-alkoxycarbonylazacycloalkyl group are more preferable, and dimethylaminoethyl And more preferred are Nt-butoxycarbonyl azacyclohexyl group.

  Examples of the structural unit (V) include structural units represented by the following formulas (8-1) to (8-8) (hereinafter, “structural units (Va-1) to (Va-8)”). Also).

In the above formula (8-1) ~ (8-8), ^{R U} is as defined in the above formula (8).

  Among these, the structural units (Va-1) to (Va-5) and the structural unit (Va-8) are preferable, and the structural units (Va-1) to (V-) are preferable. a-5) is more preferred, and structural units (Va-1) and (Va-5) are more preferred.

  [A] When the polymer component has a structural unit (V), the lower limit of the content ratio of the structural unit (V) is preferably 5 mol% with respect to all the structural units constituting the [A] polymer component. 10 mol% is more preferable, 15 mol% is further more preferable, and 20 mol% is especially preferable. As an upper limit of the said content rate, 50 mol% is preferable, 40 mol% is more preferable, 30 mol% is further more preferable, 25 mol% is especially preferable.

  [A] When the polymer component is the [A1] polymer component, the lower limit of the content ratio of the structural unit (V) is preferably 5 mol% with respect to all the structural units constituting the polymer (a). 10 mol% is more preferable, 15 mol% is further more preferable, and 20 mol% is especially preferable. As an upper limit of the said content rate, 50 mol% is preferable, 40 mol% is more preferable, 30 mol% is further more preferable, 25 mol% is especially preferable. Moreover, as a minimum of the content rate of a structural unit (V), 5 mol% is preferable with respect to all the structural units which comprise a polymer (b), 10 mol% is more preferable, 15 mol% is further more preferable, 20 mol% is particularly preferred. As an upper limit of the said content rate, 50 mol% is preferable, 40 mol% is more preferable, 30 mol% is further more preferable, 25 mol% is especially preferable.

  [A] When the polymer component is the [A2] polymer component, the lower limit of the content ratio of the structural unit (V) is preferably 5 mol% with respect to all the structural units constituting the polymer (c). 10 mol% is more preferable, 15 mol% is further more preferable, and 20 mol% is especially preferable. As an upper limit of the said content rate, 50 mol% is preferable, 40 mol% is more preferable, 30 mol% is further more preferable, 25 mol% is especially preferable.

  By making the content rate of a structural unit (V) into the said range, the film loss in the exposure part of a resist film can be suppressed more.

(Structural unit (VI))
The structural unit (VI) is a structural unit including a lactone structure, a cyclic carbonate structure, a sultone structure, or a combination thereof.

  Examples of the structural unit (VI) include the structural unit (q) of the polymer (P) of the above-mentioned radiation sensitive resin composition (I).

  As the structural unit (VI), a structural unit containing a lactone structure is preferred, a structural unit containing a butyrolactone structure is more preferred, and a structural unit derived from butyrolactone-yl (meth) acrylate is more preferred.

  [A] When the polymer component has a structural unit (VI), the lower limit of the content ratio of the structural unit (VI) is preferably 5 mol% with respect to all the structural units constituting the [A] polymer component. 10 mol% is more preferable, 15 mol% is further more preferable, and 20 mol% is especially preferable. As an upper limit of the said content rate, 50 mol% is preferable, 40 mol% is more preferable, 30 mol% is further more preferable, 25 mol% is especially preferable.

  [A] When the polymer component is the [A1] polymer component, the lower limit of the content ratio of the structural unit (VI) is preferably 5 mol% with respect to all the structural units constituting the polymer (a). 10 mol% is more preferable, 15 mol% is further more preferable, and 20 mol% is especially preferable. As an upper limit of the said content rate, 50 mol% is preferable, 40 mol% is more preferable, 30 mol% is further more preferable, 25 mol% is especially preferable. Moreover, as a minimum of the content rate of structural unit (VI), 5 mol% is preferable with respect to all the structural units which comprise a polymer (b), 10 mol% is more preferable, 15 mol% is further more preferable, 20 mol% is particularly preferred. As an upper limit of the said content rate, 50 mol% is preferable, 40 mol% is more preferable, 30 mol% is further more preferable, 25 mol% is especially preferable.

  [A] When the polymer component is the [A2] polymer component, the lower limit of the content ratio of the structural unit (VI) is preferably 5 mol% with respect to all the structural units constituting the polymer (c). 10 mol% is more preferable, 15 mol% is further more preferable, and 20 mol% is especially preferable. As an upper limit of the said content rate, 50 mol% is preferable, 40 mol% is more preferable, 30 mol% is further more preferable, 25 mol% is especially preferable.

  [A] The polymer component may have other structural units in addition to the structural units (I) to (VI). Examples of other structural units include a structural unit containing a non-dissociable chain hydrocarbon group or aromatic hydrocarbon group, and a structural unit containing a hydroxy group. Examples of the non-dissociable chain hydrocarbon group include a methyl group, an ethyl group, a propyl group, a butyl group, and a pentyl group. Examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, a benzyl group, and a naphthylmethyl group. As an upper limit of the content rate of another structural unit, 20 mol% is preferable with respect to all the structural units which comprise a [A] polymer component, and 10 mol% is more preferable.

  [A1] The lower limit of the mass ratio of the polymer (a) to the polymer (b) in the polymer component is preferably 10/90, more preferably 30/70, further preferably 50/50, and 60/40. Particularly preferred, 65/35 is even more preferred, and 70/30 is most preferred. The upper limit of the mass ratio is preferably 95/5, more preferably 90/10, and still more preferably 85/15. By setting the mass ratio of the polymer (a) and the polymer (b) in the above range, the upper film forming composition (I) containing the polymer component [A1] Both aqueous properties and development defect suppression can be further enhanced.

[Other polymers]
The composition for forming an upper layer film (I) may contain a polymer other than the polymer (a) and the polymer (b) as the [A1] polymer component. The composition for forming an upper layer film (I) may contain a polymer other than the polymer (c) as the [A2] polymer component. Examples of the other polymer include polymers having no structural unit (I) and no structural unit (II), and are composed of at least one of the structural units (III) to (V) and other structural units. A polymer etc. are mentioned.

[A] The lower limit of the fluorine atom content in the polymer component is 2% by mass, preferably 5% by mass, more preferably 7% by mass, and particularly preferably 10% by mass. The upper limit of the fluorine atom content is 30% by mass, preferably 25% by mass, more preferably 20% by mass, and particularly preferably 15% by mass. [A] By making the fluorine atom content rate of a polymer component into the said range, the water repellency and development defect inhibitory property of the surface of an upper layer film | membrane can be improved together. [A] The fluorine atom content (% by mass) in the polymer component is determined by ¹ H-NMR, ¹³ C-NMR, ¹⁹ F-NMR, etc. to determine the structure of the polymer constituting the [A] polymer component, It can be calculated from the structure.

<[A] Polymer component synthesis method>
[A] The polymer (a), polymer (b), polymer (c) and other polymers constituting the polymer component are, for example, a predetermined monomer, an appropriately selected polymerization initiator or chain. It can be synthesized by polymerization such as radical polymerization in a polymerization solvent in the presence of a transfer agent.

Examples of the polymerization solvent include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, ethylene glycol, diethylene glycol, and propylene glycol;
Cyclic ethers such as tetrahydrofuran and dioxane;
Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl Alkyl ethers of polyhydric alcohols such as ethers;
Alkyl ether acetates of polyhydric alcohols such as ethylene glycol ethyl ether acetate, diethylene glycol ethyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol monomethyl ether acetate;
Aromatic hydrocarbons such as toluene and xylene;
Ketones such as acetone, 2-butanone, methyl isobutyl ketone, cyclohexanone, 4-hydroxy-4-methyl-2-pentanone, diacetone alcohol;
Ethyl acetate, butyl acetate, methyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, 2-hydroxy-3-methylbutane And esters such as methyl acid, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, and the like. Of these, cyclic ethers, polyhydric alcohol alkyl ethers, polyhydric alcohol alkyl ether acetates, ketones or esters are preferred. In addition, the said polymerization solvent can use 1 type (s) or 2 or more types.

  [A] The lower limit of the Mw of the polymer component is preferably 2,000, more preferably 3,000, still more preferably 4,000, and particularly preferably 5,000. The upper limit of Mw is preferably 50,000, more preferably 30,000, still more preferably 20,000, and particularly preferably 10,000.

  When the [A] polymer component is the [A1] polymer component, the lower limit of the weight average molecular weight (Mw) in terms of polystyrene by gel permeation chromatography (GPC) of the polymer (a) is preferably 2,000. 3,000 is more preferable, 4,000 is further more preferable, and 5,000 is particularly preferable. The upper limit of Mw is preferably 50,000, more preferably 30,000, still more preferably 20,000, and particularly preferably 10,000. Moreover, as a minimum of Mw of a polymer (b), 2,000 is preferable, 3,000 is more preferable, 4,000 is further more preferable, 5,000 is especially preferable. The upper limit of Mw is preferably 50,000, more preferably 30,000, still more preferably 20,000, and particularly preferably 10,000.

  When the [A] polymer component is the [A2] polymer component, the lower limit of the Mw of the polymer (c) is preferably 2,000, more preferably 3,000, still more preferably 4,000, 5 Is particularly preferred. The upper limit of Mw is preferably 50,000, more preferably 30,000, still more preferably 20,000, and particularly preferably 10,000.

  [A] By setting the Mw of the polymer in the polymer component in the above range, the solubility of the polymer in the developer can be appropriately adjusted, and as a result, the occurrence of development defects in the resist pattern is further suppressed. be able to.

  [A] The upper limit of the Mw / Mn ratio of the polymer component is preferably 5, more preferably 3, more preferably 2.5, and particularly preferably 2. The lower limit of the ratio is usually 1 and preferably 1.1.

  When the polymer component [A] is the polymer component [A1], the upper limit of the ratio (Mw / Mn) of the Mw of the polymer (a) to the number average molecular weight (Mw) in terms of polystyrene by GPC is preferably 5. 3 is more preferable, 2.5 is more preferable, and 2 is particularly preferable. The lower limit of the ratio is usually 1 and preferably 1.1. Further, the upper limit of the Mw / Mn ratio of the polymer (b) is preferably 5, more preferably 3, more preferably 2.5, and particularly preferably 2. The lower limit of the ratio is usually 1 and preferably 1.1.

  [A] When the polymer component is the [A2] polymer component, the upper limit of the Mw / Mn ratio of the polymer (c) is preferably 5, more preferably 3, more preferably 2.5, and 2 Particularly preferred. The lower limit of the ratio is usually 1 and preferably 1.1.

  By setting the Mw / Mn ratio in the above range, the solubility of the polymer in the developer can be further increased, and as a result, both the water repellency and the development defect suppression of the upper film surface can be further enhanced. .

  The upper layer film-forming composition (I) is preferably as less as possible as impurities such as halogen ions and metals. By reducing the impurities, it is possible to improve the applicability as the composition (I) for forming the upper film and the uniform solubility of the upper film in the developer containing the organic solvent. Examples of methods for purifying the polymer component [A] in order to reduce impurities include chemical purification methods such as water washing, liquid-liquid extraction, and demetalization filter passage, and these chemical purification methods and ultrafiltration and centrifugation. A combination with a physical purification method such as separation may be mentioned.

  [A] The lower limit of the content of the polymer component is preferably 90% by mass, more preferably 95% by mass, and further 99% by mass with respect to the total solid content in the composition for forming an upper layer film (I). preferable. The upper limit of the content is usually 100% by mass.

<[B] Solvent>
The upper layer film-forming composition (I) contains a [B] solvent. [B] The solvent is not particularly limited as long as it can dissolve or disperse the [A] polymer component and other components of the [C] compound contained as necessary.

  [B] Examples of the solvent include the solvents exemplified as the organic solvent contained in the developer in the development step. The composition (I) for forming the upper layer film can contain the [B] solvent alone or in combination of two or more.

  [B] The solvent is preferably an ester solvent, a ketone solvent, an amide solvent, a cyclic ether solvent, an alcohol solvent, or a combination thereof. As the alcohol solvent, those having 5 or more carbon atoms are preferable. In particular, when the [A] polymer component is the [A3] polymer component, the solvent is preferably used from the viewpoint of further improving the water repellency of the upper film surface.

<Other ingredients>
The composition (I) for forming the upper layer film may contain other components in addition to the [A] polymer component and the [B] solvent. Examples of other components include [C] basic compounds and surfactants.

[[C] Compound]
[C] The compound is a basic compound, a compound that generates a basic compound by the action of an acid, or a combination thereof. The compound [C] acts on the exposed portion of the resist film below the upper layer film to be formed, thereby suppressing the deprotection, thereby further reducing the film loss in resist pattern formation. Moreover, the inhibitory property of the blob defect in a resist pattern can be improved.

  Examples of the basic compound include a (cyclo) alkylamine compound, a nitrogen-containing heterocyclic compound, an amide group-containing compound, a urea compound, a photodegradable base compound, and the like.

  Examples of (cyclo) alkylamine compounds include compounds having one nitrogen atom, compounds having two nitrogen atoms, compounds having three or more nitrogen atoms, and the like.

Examples of the compound having one nitrogen atom include mono (cyclo) alkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, 1-aminodecane, and cyclohexylamine;
Di-n-butylamine, di-n-pentylamine, di-n-hexylamine, di-n-heptylamine, di-n-octylamine, di-n-nonylamine, di-n-decylamine, cyclohexylmethylamine, Di (cyclo) alkylamines such as dicyclohexylamine;
Triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri -Tri (cyclo) alkylamines such as n-decylamine, cyclohexyldimethylamine, methyldicyclohexylamine, tricyclohexylamine;
Substituted alkylamines such as triethanolamine and tri (n-hexyloxyethyl) amine;
Aniline, N-methylaniline, N, N-dimethylaniline, 2-methylaniline, 3-methylaniline, 4-methylaniline, N, N-dibutylaniline, 4-nitroaniline, diphenylamine, triphenylamine, naphthylamine, 2 , 4,6-tri-tert-butyl-N-methylaniline, N-phenyldiethanolamine, 2,6-diisopropylaniline, 2- (4-aminophenyl) -2- (3-hydroxyphenyl) propane, 2- ( And aromatic amines such as 4-aminophenyl) -2- (4-hydroxyphenyl) propane.

  Examples of the compound having two nitrogen atoms include ethylenediamine, tetramethylethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether, 4,4′-diaminobenzophenone, 4 , 4′-diaminodiphenylamine, 2,2-bis (4-aminophenyl) propane, 2- (3-aminophenyl) -2- (4-aminophenyl) propane, 1,4-bis [1- (4- Aminophenyl) -1-methylethyl] benzene, 1,3-bis [1- (4-aminophenyl) -1-methylethyl] benzene, bis (2-dimethylaminoethyl) ether, bis (2-diethylaminoethyl) Ether, 1- (2-hydroxyethyl) -2-imidazolidinone, - quinoxalinium linoleic, N, N, N ', N'- tetrakis (2-hydroxypropyl) ethylenediamine, and the like.

  Examples of the compound having 3 or more nitrogen atoms include polyethyleneimine, polyallylamine, 2-dimethylaminoethylacrylamide polymer, and the like.

  Examples of the nitrogen-containing heterocyclic compound include nitrogen-containing aromatic heterocyclic compounds and nitrogen-containing aliphatic heterocyclic compounds.

Examples of the nitrogen-containing aromatic heterocyclic compound include imidazole, 4-methylimidazole, 4-methyl-2-phenylimidazole, benzimidazole, 2-phenylbenzimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2. Imidazoles such as methyl-1H-imidazole;
Pyridine, 2-methylpyridine, 4-methylpyridine, 2-ethylpyridine, 4-ethylpyridine, 2-phenylpyridine, 4-phenylpyridine, 2-methyl-4-phenylpyridine, nicotine, nicotinic acid, nicotinamide, Examples thereof include pyridines such as quinoline, 4-hydroxyquinoline, 8-oxyquinoline, acridine, and 2,2 ′: 6 ′, 2 ″ -terpyridine.

Examples of the nitrogen-containing aliphatic heterocyclic compound include piperazines such as piperazine and 1- (2-hydroxyethyl) piperazine;
Pyrazine, pyrazole, pyridazine, quinosaline, purine, pyrrolidine, proline, piperidine, piperidine ethanol, 3-piperidino-1,2-propanediol, morpholine, 4-methylmorpholine, 1- (4-morpholinyl) ethanol, 4-acetylmorpholine , 3- (N-morpholino) -1,2-propanediol, 1,4-dimethylpiperazine, 1,4-diazabicyclo [2.2.2] octane, and the like.

  Examples of the amide group-containing compound include formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide, benzamide, pyrrolidone, N-methylpyrrolidone, N- Examples include acetyl-1-adamantylamine, isocyanuric acid tris (2-hydroxyethyl), and the like.

  Examples of urea compounds include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, tri-n-butylthiourea and the like. Is mentioned.

  As a compound which produces | generates a basic compound by the effect | action of an acid, the compound etc. which substituted the hydrogen atom couple | bonded with the nitrogen atom of the said basic compound with the t-alkoxycarbonyl group etc. are mentioned, for example. .

Examples of the compound that generates a basic compound by the action of an acid include Nt-butoxycarbonyldi-n-octylamine, Nt-butoxycarbonyldi-n-nonylamine, Nt-butoxycarbonyldi-n- Decylamine, Nt-butoxycarbonyldicyclohexylamine, Nt-butoxycarbonyl-1-adamantylamine, Nt-butoxycarbonyl-2-adamantylamine, Nt-butoxycarbonyl-N-methyl-1-adamantylamine , (S)-(−)-1- (t-butoxycarbonyl) -2-pyrrolidinemethanol, (R)-(+)-1- (t-butoxycarbonyl) -2-pyrrolidinemethanol, Nt-butoxy Carbonyl-4-hydroxypiperidine, Nt-butoxycarbonylpyrrolidine, N- t-butoxycarbonylpiperazine, N, N-di-t-butoxycarbonyl-1-adamantylamine, N, N-di-t-butoxycarbonyl-N-methyl-1-adamantylamine, Nt-butoxycarbonyl-4 , 4′-diaminodiphenylmethane, N, N′-di-t-butoxycarbonylhexamethylenediamine, N, N, N ′, N′-tetra-t-butoxycarbonylhexamethylenediamine, N, N′-di-t -Butoxycarbonyl-1,7-diaminoheptane, N, N'-di-t-butoxycarbonyl-1,8-diaminooctane, N, N'-di-t-butoxycarbonyl-1,9-diaminononane, N, N′-di-t-butoxycarbonyl-1,10-diaminodecane, N, N′-di-t-butoxycarbonyl-1,12-diaminodode N, N′-di-t-butoxycarbonyl-4,4′-diaminodiphenylmethane, Nt-butoxycarbonylbenzimidazole, Nt-butoxycarbonyl-2-methylbenzimidazole, Nt-butoxycarbonyl N-t-alkoxycarbonyl group-substituted nitrogen-containing compounds such as 2-phenylbenzimidazole and the like, and their t-amyloxycarbonyl-substituted products.

  The photodegradable basic compound is a compound having basicity, and is a compound which is exposed to light upon exposure to produce a weak acid and the basicity is lowered. Examples of the photodegradable base compound include onium salt compounds. Examples of the onium salt compound include a sulfonium salt compound represented by the following formula (K1) and an iodonium salt compound represented by the following formula (K2).

In the above formulas (K1) and (K2), R ^{10 to} R ¹⁴ are each independently a hydrogen atom, an alkyl group, an alkoxy group, a hydroxy group, or a halogen atom. Z ^{- is, OH -, R α -COO -} , R β -SO 2 -N - -R α, R α -SO 3 - is an anion represented by or the following formula (K3). ^Rα is a linear or branched alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms, or an aralkyl group having 7 to 30 carbon atoms. Some or all of the hydrogen atoms of the alkyl group, cycloalkyl group, aryl group and aralkyl group may be substituted. ^Rβ is a linear or branched alkyl group having 1 to 10 carbon atoms or a cycloalkyl group having 3 to 20 carbon atoms which may have a substituent. Some or all of the hydrogen atoms of the alkyl group and cycloalkyl group may be substituted with fluorine atoms. However, when Z ⁻ is R ^α —SO ₃ ^— , a fluorine atom is not bonded to a carbon atom to which SO ₃ ^— is bonded.

In the above formula (K3), R ¹⁵ is a linear or branched alkyl group having 1 to 12 carbon atoms in which part or all of the hydrogen atoms may be substituted with fluorine atoms, or 1 to 12 carbon atoms. These are linear or branched alkoxy groups. u is an integer of 0-2.

  Examples of the photodegradable base include compounds represented by the following formulas.

  [C] The compound is preferably a (cyclo) alkylamine compound, a nitrogen-containing heterocyclic compound, a compound that produces a (cyclo) alkylamine compound by the action of an acid, or a compound that produces a nitrogen-containing heterocyclic compound by the action of an acid. , (Cyclo) alkylamine compounds and compounds that generate nitrogen-containing heterocyclic compounds by the action of acids are more preferred, substituted alkylamines and Nt-alkoxycarbonyl substituted nitrogen-containing aliphatic heterocyclic compounds are more preferred, and tri ( n-hexyloxyethyl) amine and Nt-amyloxycarbonyl-4-hydroxypiperidine are particularly preferred.

  When composition (I) for upper layer film formation contains a [C] compound, as a minimum of content of a [C] compound, 0.01 mass part is with respect to 100 mass parts of [A] polymer components. Preferably, 0.1 mass part is more preferable, 0.2 mass part is further more preferable, and 0.5 mass part is especially preferable. The upper limit of the content is preferably 10 parts by mass, more preferably 5 parts by mass, further preferably 3 parts by mass, and particularly preferably 2 parts by mass. By setting the content of the [C] compound in the above range, film loss in resist pattern formation can be further reduced. [C] A compound can be used individually by 1 type or in mixture of 2 or more types.

[Surfactant]
The surfactant is a component for improving the coating property of the upper layer film-forming composition (I). A commercial item can also be used as said surfactant. As an upper limit of content of the said surfactant, 5 mass parts is preferable with respect to 100 mass parts of [A] polymer components, and 2 mass parts is more preferable.

<Method for Preparing Composition for Forming Upper Film (I)>
The composition for forming the upper layer film (I) is preferably obtained by mixing, for example, the [A] polymer component and, if necessary, the other component such as the [C] compound with the [B] solvent and dissolving them. The obtained mixture can be prepared by filtering through a membrane filter of about 0.2 μm. As a minimum of solid content concentration of composition (I) for upper layer film formation, 0.1 mass% is preferred, 0.3 mass% is more preferred, and 0.5 mass% is still more preferred. As an upper limit of the said solid content concentration, 30 mass% is preferable, 20 mass% is more preferable, and 10 mass% is further more preferable.

<Composition for forming upper layer film>
The composition for forming an upper layer film of the present invention is a composition for forming an upper layer film used in a negative resist pattern forming method using a developer containing an organic solvent, and the structural unit ( [A] A polymer component containing a structural unit (II) and a solvent, and a fluorine atom content in the [A] polymer component is 2% by mass or more and 30% by mass or less. It is characterized by.

  It is preferable that the organic solvent of the developer includes an ester solvent, a ketone solvent, and a combination thereof.

  The upper layer film forming composition is described as the upper layer film forming composition (I) in the negative resist pattern forming method.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. The measuring method of various physical property values is shown below.

[Measurement of Mw and Mn]
Mw and Mn of the polymer were measured by gel permeation chromatography (GPC) under the following conditions.
GPC column: 2 Tosoh “G2000HXL”, 1 “G3000HXL” and 1 “G4000HXL” Elution solvent: Tetrahydrofuran Flow rate: 1.0 mL / min Column temperature: 40 ° C.
Standard material: Monodisperse polystyrene Detector: Differential refractometer

[ ¹ H-NMR, ¹³ C-NMR analysis and ¹⁹ F-NMR analysis]
For the ¹ H-NMR and ¹³ C-NMR analysis of the polymer, a nuclear magnetic resonance apparatus (“JNM-ECX400” manufactured by JEOL Ltd.) was used, acetone-d6 was used as a measurement solvent, and tetramethylsilane (TMS). Was measured as an internal standard.

<[A] Synthesis of polymer component>
[A] The monomers used for the synthesis of the polymer component are shown below.

  Monomers (M-1) to (M-4) are structural units (I), monomers (M-5) to (M-9) are structural units (II), M-10) and (M-11) represent the structural unit (V), the monomer (M-12) represents the structural unit (IV), and the monomer (M-13) represents the structural unit (VI). give.

[Synthesis Example 1]
100 g of the above monomer (M-1) was dissolved in 200 g of 2-butanone, and 4.11 g of 2,2′-azobis (methyl 2-methylpropionate) as a radical polymerization initiator (total amount of monomers) 3 mol%) was added to prepare a monomer solution. A 1,000-mL three-necked flask containing 100 g of 2-butanone was purged with nitrogen for 30 minutes, and then the flask was heated to 80 ° C. while stirring with a magnetic stirrer, and the prepared monomer solution was added using a dropping funnel for 3 hours. It was dripped over. The dripping start was set as the polymerization reaction start time, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization reaction, the polymerization reaction solution was cooled with water and cooled to 30 ° C. or lower. A polymerization reaction solution cooled in 2,000 g of methanol was added, and the precipitated white powder was separated by filtration. The filtered white powder was washed twice with 400 g of methanol, filtered, and dried at 60 ° C. for 17 hours to obtain a white powdery polymer (a-1) (yield 79.9 g, yield). 79.9%). Mw of the obtained polymer (a-1) was 12,000, and Mw / Mn was 1.76.

[Synthesis Examples 2 to 9]
Polymers (a-2) to (a-9) were synthesized in the same manner as in Synthesis Example 1 except that the types and amounts of monomers listed in Table 1 were used. The total mass of the monomers used was 100 g. In Table 1, “-” indicates that the corresponding component was not used. The content ratio, yield, Mw, and Mw / Mn of each structural unit of the obtained polymer are shown in Table 1.

[Synthesis Example 10]
36.4 g of the monomer (M-6) and 63.6 g of the monomer (M-8) were dissolved in 200 g of 2-butanone, and 2,2′-azobis- (2- 2.99 g of methyl methyl propionate (3 mol% based on the total amount of monomers) was added to prepare a monomer solution. A 1,000-mL three-necked flask containing 100 g of 2-butanone was purged with nitrogen for 30 minutes, and then the flask was heated to 80 ° C. while stirring with a magnetic stirrer, and the prepared monomer solution was added using a dropping funnel for 3 hours. It was dripped over. The dripping start was set as the polymerization reaction start time, and the polymerization reaction was carried out for 6 hours. Next, the obtained polymerization reaction liquid was transferred to a separatory funnel, and 56 g of methanol and 240 g of heptane were added to the separatory funnel to carry out separation purification. After separation, the lower layer solution was recovered. The recovered lower layer liquid was replaced with 4-methyl-2-pentanol to obtain a liquid containing the polymer (b-1). 0.5 g of the liquid containing the polymer (b-1) is placed on an aluminum dish and heated on a hot plate heated to 155 ° C. for 30 minutes, and then the liquid containing the polymer (b-1) is obtained from the mass of the residue. The solid content concentration was calculated, and the value of the solid content concentration was used in the subsequent preparation of the composition for forming an upper layer film and the yield calculation.

[Synthesis Examples 11 to 14]
The polymers (b-2), (c-1), (c-2) and (d) were prepared in the same manner as in Synthesis Example 10 except that the types and amounts of monomers listed in Table 1 were used. -1) was synthesized respectively. The total mass of the monomers used was 100 g. In Table 1, “-” indicates that the corresponding component was not used. The content ratio, yield, Mw, and Mw / Mn of each structural unit of the obtained polymer are shown in Table 1.

<Preparation of composition for forming upper layer film>
[B] solvent used for preparation of the composition for forming the upper layer film is shown below.

[[B] solvent]
B-1: 4-methyl-2-pentanol B-2: 2-heptanol B-3: Diisoamyl ether B-4: n-decane

[Example 1]
[A] A liquid containing 70 parts by mass of the polymer (a-1) as a polymer component and 30 parts by mass of the polymer (b-1), and [B] 1,410 parts by mass as a solvent (B-1) Part and (B-3) 5,630 parts by mass, and the resulting mixture was filtered through a 0.2 μm membrane filter to prepare an upper layer film-forming composition (J-1). [A] The mass content of fluorine atoms in the polymer component was 13.7% by mass.

[Examples 2 to 16 and Comparative Examples 1 to 5]
Except having used each component of the kind and content shown in following Table 2, it is the same as that of Example 1, and the composition for upper layer film formation (J-2)-(J-16) and (CJ-1)-( CJ-5) was prepared. Table 2 shows the value of the mass content (% by mass) of fluorine atoms in the [A] polymer component of the composition for forming an upper layer film.

<Preparation of radiation-sensitive resin composition>
The radiation sensitive resin composition used for resist film formation was prepared by the following method.

[Synthesis of polymer containing [P] acid dissociable group]
The monomer used for the synthesis | combination of the polymer containing a [P] acid dissociable group is shown below.

[Synthesis Example 15]
37.5 g (50 mol%) of the monomer (r-1) and 62.5 g (50 mol%) of the monomer (r-2) were dissolved in 200 g of 2-butanone, and further 2,2′-azobis A monomer solution in which 3.7 g of methyl 2-methylpropionate (5 mol% based on the total amount of monomers) was dissolved was prepared. A 500 mL three-necked flask charged with 100 g of 2-butanone was purged with nitrogen for 30 minutes. After purging with nitrogen, the reaction kettle was heated to 80 ° C. with stirring, and the monomer solution prepared above was dropped over 3 hours using a dropping funnel. The polymerization start was carried out for 6 hours with the start of dropping as the polymerization start time. After completion of the polymerization, the polymerization reaction liquid was cooled to 30 ° C. or lower by water cooling, and then poured into 2,000 g of methanol, and the precipitated white powder was filtered off. The filtered white powder was washed twice in a slurry using 400 g of methanol, filtered, and dried at 50 ° C. for 17 hours to obtain a white powder polymer (P-1). Obtained (yield 70.5 g, yield 70.5%). Mw of this polymer (P-1) was 6,500, and Mw / Mn was 1.40. As a result of ¹³ C-NMR analysis, the content ratios of the structural units derived from (r-1) and (r-2) were 49 mol% and 51 mol%, respectively.

[Preparation of radiation-sensitive resin composition]
The [Q] acid generator, [R] acid diffusion controller and [S] solvent used for the preparation of the radiation sensitive resin composition are shown below.

[[Q] acid generator]
Q-1: Triphenylsulfonium 2- (norbornan-2-yl) -1,1-difluoroethane-1-sulfonate (compound represented by the following formula (Q-1))

[[R] acid diffusion controller]
R-1: Nt-butoxycarbonyl-4-hydroxypiperidine (compound represented by the following formula (R-1))

[[S] solvent]
S-1: Propylene glycol monomethyl ether acetate S-2: Cyclohexanone S-3: γ-butyrolactone

[Synthesis Example 16]
[P] (P-1) 100 parts by mass as a polymer, [Q] (Q-1) 7.8 parts by mass as an acid generator, [R] (R-1) 1 as an acid diffusion controller (S-1) 2,110 parts by weight as [S] solvent, (S-2) 900 parts by weight and (S-3) 30 parts by weight are mixed, and the resulting mixture has a pore size of 0.2 μm. A radiation sensitive resin composition (α) was prepared by filtering through a membrane filter.

<Evaluation>
Various evaluations shown below were performed on the prepared composition for forming an upper layer film. The evaluation results are shown in Table 3 below.

[Composition stability]
The presence or absence of white turbidity of the composition for forming an upper layer film over time was evaluated. After stirring the upper layer film-forming composition for 30 minutes, the presence or absence of cloudiness was visually observed. The composition stability was evaluated as “A (good)” when no cloudiness was observed, and “B (bad)” when any cloudiness was observed.

[Backward contact angle]
The receding contact angle value of water on the upper film surface was measured. The composition for forming an upper layer film was spin-coated on an 8-inch silicon wafer, and PB was performed on a hot plate at 90 ° C. for 60 seconds to form an upper layer film having an average thickness of 30 nm. Thereafter, using a contact angle meter (“DSA-10” manufactured by KRUS), the receding contact angle was quickly measured by the following procedure in an environment of room temperature 23 ° C., humidity 45%, and normal pressure.
First, the wafer stage position of the contact angle meter was adjusted, and the wafer was set on the adjusted stage. Next, water was injected into the needle, and the position of the needle was finely adjusted to an initial position where water droplets could be formed on the set wafer. Thereafter, water was discharged from the needle to form a 25 μL water droplet on the wafer. The needle was once pulled out from the water droplet and then pulled down again at the initial position and placed in the water droplet. Subsequently, a water droplet was sucked with a needle at a speed of 10 μL / min for 90 seconds, and at the same time, the contact angle was measured once per second for a total of 90 times. Among these, the average value for the contact angle for 20 seconds from the time when the measured value of the contact angle was stabilized was calculated and set as the receding contact angle (unit: degree (°)).
When the receding contact angle is 80 ° or more, it can be judged as “good”, and when it is less than 80 °, it can be judged as “bad”.

[Elution suppression]
The elution amount of the resist component from the resist film on which the upper layer film was formed was measured. In the center of an 8-inch silicon wafer that has been subjected to hexamethyldisilazane (HMDS) processing (100 ° C. for 60 seconds) using a coating / developing apparatus (“CLEAN TRACK ACT8” manufactured by Tokyo Electron Ltd.), the center has a diameter of 11 A silicon rubber sheet (Kureha Elastomer Co., Ltd., 1.0 mm thick, 30 cm square) was placed on a 3 cm circle. Next, 10 mL of ultrapure water was filled in the hollowed out portion at the center of the silicon rubber using a 10 mL hole pipette. On the other hand, separately from the silicon wafer, an 8-inch silicon wafer on which a lower antireflection film, a resist film, and an upper film are formed is prepared, and the 8-inch silicon wafer is placed so that the upper film is positioned on the silicon rubber sheet side, The upper layer membrane and ultrapure water were brought into contact with each other while being placed so that the ultrapure water did not leak. The silicon wafer on which the lower antireflection film, the resist film and the upper film were formed was coated / developed with the composition for forming the lower antireflection film (“ARC29A” from Brewer Science) on an 8-inch silicon wafer. The lower antireflection film having an average thickness of 77 nm is formed by spin coating using an apparatus, and then the radiation sensitive resin composition (α) is spin coated on the lower antireflection film using the coating / developing apparatus. Then, a resist film having an average thickness of 90 nm is formed by performing PB at 90 ° C. for 60 seconds, and then, an upper layer film-forming composition is applied on this resist film, and PB is performed at 90 ° C. for 60 seconds. It was obtained by forming an upper layer film having an average thickness of 30 nm. After placing the upper layer film, the state was maintained for 10 seconds. Thereafter, the other 8-inch silicon wafer was removed, and ultrapure water was collected with a glass syringe, which was used as a sample for analysis. Note that the recovery rate of ultrapure water after the experiment was 95% or more. Next, the peak intensity of the anion part of the photoacid generator in the ultrapure water obtained above was measured by liquid chromatography mass spectrometer (LC-MS) (LC part: “SERIES1100” from AGILENT, MS part: Perseptive Biosystems. , Inc. "Mariner") under the following measurement conditions. At that time, the peak intensity of the 1 ppb, 10 ppb, and 100 ppb aqueous solutions of the [Q] acid generator used in the radiation sensitive resin composition (α) was measured under the following measurement conditions to prepare a calibration curve. The elution amount was calculated from the peak intensity using a line. When the dissolution amount is 5.0 × 10 ⁻¹² mol / cm ² or less, the dissolution inhibition property is “A (good)”, and when the dissolution amount is larger than 5.0 × 10 ⁻¹² mol / cm ² It was evaluated as “B (defect)”.
(Measurement condition)
Column used: “CAPCELL PAK MG” manufactured by Shiseido Co., Ltd. Flow rate: 0.2 mL / min Eluent: Water / methanol (volume ratio: 3/7) with 0.1% by mass of formic acid Measurement temperature: 35 ℃

[Peeling resistance]
The difficulty of peeling the upper layer film from the substrate was evaluated. As the substrate, an 8-inch silicon wafer not subjected to HMDS treatment was used. The composition for forming an upper layer film was spin-coated on the substrate using the coating / developing apparatus, and then PB was performed at 90 ° C. for 60 seconds to form an upper layer film having an average thickness of 30 nm. Next, rinsing with pure water was performed for 60 seconds in the coating / developing apparatus, and drying was performed by shaking off. The peel resistance is “A (good)” when no peeling of the upper layer film is visually observed after rinsing, and “B (slightly good)” when peeling of only the edge portion is recognized. When peeling of was recognized, it was evaluated as “C (defect)”.

[Bridge defect suppression and disconnection defect suppression]
The number of occurrences of bridge defects and disconnection defects in the resist pattern obtained by exposing and developing the resist film on which the upper layer film was formed was evaluated.
A 12-inch silicon wafer surface was spin-coated using a coating / developing apparatus (“Lithius Pro-i” from Tokyo Electron) with a composition for forming an underlayer antireflection film (“ARC66” from Nissan Chemical Co., Ltd.) By performing PB, a lower antireflection film having an average thickness of 105 nm was formed. Next, using the above coating / developing apparatus, the radiation-sensitive resin composition (α) was spin-coated, PB was performed at 90 ° C. for 60 seconds, and then cooled at 23 ° C. for 30 seconds, so that the average thickness was 90 nm. The resist film was formed. Then, the composition for upper layer film formation was apply | coated on this resist film, and the upper layer film of average thickness 30nm was formed by performing PB for 60 second at 90 degreeC.
Next, using an ArF immersion exposure apparatus (“S610C” manufactured by NIKON), exposure was performed through a mask for pattern formation of 45 nm line / 90 nm pitch under the optical conditions of NA: 1.30 and Dipole. Next, PEB was performed at 90 ° C. for 60 seconds on the hot plate of the coating / developing apparatus, cooled at 23 ° C. for 30 seconds, and then subjected to paddle development for 30 seconds using butyl acetate as a developer. Thereafter, spin drying was performed by swinging off at 2,000 rpm for 15 seconds to obtain a substrate on which a resist pattern was formed. The substrate on which the obtained resist pattern is formed is subjected to defect inspection using a defect inspection apparatus (“KLA2810” from KLA-Tencor), and using a scanning electron microscope (“RS6000” from Hitachi High-Technologies Corporation). Observation and measurement of bridge defects and disconnection defects. The bridge defect suppression property and the disconnection defect suppression property can be evaluated as “good” when the number of defects is less than 50 per wafer, and as “bad” when the number of defects is 50 or more.

  From the results of Table 3, according to the composition for forming the upper layer film and the negative resist pattern forming method of the examples, the upper layer having a high receding contact angle and excellent peeling resistance while maintaining the composition stability and the elution suppression property. It can be seen that a film can be formed and a resist pattern with few bridge defects and disconnection defects can be formed. On the other hand, when the composition for forming an upper layer film of the comparative example and the negative resist pattern forming method were used, at least any one of the receding contact angle, the peeling resistance, the bridge defect suppressing property and the disconnection defect suppressing property was poor.

  According to the method for forming a negative resist pattern and the composition for forming an upper layer film of the present invention, in forming a negative pattern using a developer containing an organic solvent, the water repellency on the surface of the upper layer film can be increased and development defects can be achieved. A resist pattern with less can be formed. Therefore, the negative resist pattern forming method and the composition for forming an upper layer film can be suitably used for pattern formation in the field of semiconductor devices and the like that will require further miniaturization and higher quality in the future.

Claims (15)

Forming a resist film;
A step of forming an upper layer film on one surface of the resist film with the upper layer film forming composition;
A step of immersion exposure of the resist film on which the upper layer film is formed; and a step of developing the resist film subjected to the immersion exposure with a developer containing an organic solvent,
The composition for forming an upper layer film is
In the same or different polymer, a polymer component having a first structural unit containing an alicyclic structure and a second structural unit containing a fluorine atom other than the first structural unit, and a solvent,
The negative resist pattern formation method whose fluorine atom content rate in the said polymer component is 2 to 30 mass%. The negative resist pattern forming method according to claim 1, wherein the first structural unit is represented by the following formula (1-1) or (1-2).

(In Formula (1-1), R ¹ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. L is a single bond or a divalent organic group having 1 to 20 carbon atoms. ² is a substituted or unsubstituted monovalent alicyclic hydrocarbon group having 3 to 20 ring members.
In formula (1-2), R ^{1 ′} represents a hydrogen atom or a methyl group. Y ¹ , Y ² and Y ³ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. a is an integer of 1 to 4. When a is 2 or more, the plurality of Y ¹ may be the same or different, and the plurality of Y ² may be the same or different. L ′ is a single bond or a divalent organic group having 1 to 20 carbon atoms. R ^{2 ′} is a substituted or unsubstituted monovalent alicyclic hydrocarbon group having 3 to 20 ring members. ) The negative resist pattern forming method according to claim 2, wherein R ² in the formula (1-1) and R ^{2 ′} in the formula (1-2) are unsubstituted.   The negative resist pattern forming method according to claim 1, wherein the fluorine atom content in the polymer component is 25% by mass or less.   The negative type according to any one of claims 1 to 4, wherein the polymer component includes a first polymer having the first structural unit and a second polymer having the second structural unit. Resist pattern forming method.   The negative resist pattern forming method according to claim 5, wherein a mass ratio of the first polymer to the second polymer is 10/90 or more and 95/5 or less.   The negative resist pattern forming method according to any one of claims 1 to 4, wherein the polymer component includes a third polymer having the first structural unit and the second structural unit.   The negative resist pattern formation according to any one of claims 1 to 7, wherein the solvent is an ester solvent, a ketone solvent, an amide solvent, a cyclic ether solvent, an alcohol solvent, or a combination thereof. Method.   The negative resist pattern forming method according to any one of claims 1 to 8, wherein the alicyclic structure is a polycyclic structure.   The negative resist pattern according to any one of claims 1 to 9, wherein a content ratio of the first structural unit with respect to all structural units constituting the polymer component is 20 mol% or more and 95 mol% or less. Forming method. The negative resist pattern forming method according to any one of claims 1 to 10, wherein the second structural unit includes a group represented by the following formula (2).

(In Formula (2), R ^A is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. R ^B and R ^C are each independently a fluorine atom or fluorine having 1 to 20 carbon atoms. Alkyl group.)   The negative resist pattern forming method according to any one of claims 1 to 11, wherein the organic solvent of the developer used in the developing step includes an ester solvent, a ketone solvent, or a combination thereof.   The negative resist pattern forming method according to any one of claims 1 to 12, further comprising a step of removing the upper layer film after the immersion exposure step and simultaneously with or before the development step. An upper layer film-forming composition used in a negative resist pattern forming method using a developer containing an organic solvent,
In the same or different polymer, a polymer component having a first structural unit containing an alicyclic structure and a second structural unit containing a fluorine atom other than the first structural unit, and a solvent,
The composition for forming an upper layer film, wherein a fluorine atom content in the polymer component is 2% by mass or more and 30% by mass or less.   The composition for forming an upper layer film according to claim 14, wherein the organic solvent of the developer contains an ester solvent, a ketone solvent, or a combination thereof.