JP5737211B2 - Composition for forming liquid immersion upper layer film and method for forming resist pattern - Google Patents

Description

  The present invention relates to a composition for forming a liquid immersion upper layer film and a method for forming a resist pattern.

  With the miniaturization of various electronic device structures such as semiconductor devices and liquid crystal devices, pattern miniaturization in the lithography process is required. At present, it is possible to form a fine pattern with a line width of about 90 nm using, for example, an ArF excimer laser, but further fine pattern formation will be required in the future.

  In response to such demands, the use of an immersion exposure method in which exposure is performed by filling a space between a lens and a resist film with an immersion medium such as pure water or a fluorine-based inert liquid is expanding. This immersion exposure method has the advantage that the numerical aperture (NA) of the lens can be increased and high resolution can be obtained.

  In this pattern formation method by the immersion exposure method, it is required to suppress elution of the resist film component into the immersion medium, and to suppress pattern defects caused by droplets of the immersion medium remaining on the resist film surface. As a technique for satisfying these requirements, it has been proposed to provide a protective film (immersion upper layer film) between a resist film and an immersion medium (Japanese Patent Laid-Open No. 2006-91798, International Publication No. 2008/2008). 47678 and International Publication No. 2009/41270). In these publications, a liquid immersion upper layer film is formed on a resist film using a water-insoluble and alkali-soluble polymer, and at the time of exposure, elution of resist film components is suppressed by the water repellency of the liquid immersion upper film. In addition, in the subsequent alkali development process, it is disclosed that the liquid immersion upper layer film is removed from the resist film surface by dissolving the liquid immersion upper film in the developer.

  However, when the water repellency of the liquid immersion upper layer film is increased, there is a tendency that development defects such as bridge defects in which a part of the patterns are connected in the formed resist pattern and blob defects due to adhesion of development residues increase. Thus, development of a composition for forming a liquid immersion upper layer film that is capable of simultaneously forming a liquid immersion upper layer film exhibiting high water repellency and suppressing the occurrence of defects in the formed resist pattern is desired.

JP 2006-91798 A International Publication No. 2008/47678 International Publication No. 2009/41270

  The present invention has been made on the basis of the above-described circumstances, and the purpose thereof is to form a liquid immersion upper layer film exhibiting high water repellency, and to generate development defects such as a bridge defect and a blob defect in a resist pattern. It is an object to provide a composition for forming a liquid immersion upper layer film that can suppress the above.

（式（１）中、Ｒ^１は、水素原子又はメチル基である。Ｒ^２及びＲ^３は、それぞれ独立して、水素原子、フッ素原子、ヒドロキシ基又は炭素数１〜６のアルキル基である。但し、Ｒ^２及びＲ^３が共にヒドロキシ基である場合はない。Ｒ^４及びＲ^５は、それぞれ独立して、水素原子又は炭素数１〜２０の１価の有機基であり、互いに結合して、これらが結合している炭素原子と共に炭素数３〜２０の環構造を形成してもよい。この環構造が有する水素原子の一部又は全部は、置換されていてもよい。ｎは、１〜４の整数である。ｎが２以上の場合、複数のＲ^２及びＲ^３は、それぞれ同一でも異なっていてもよい。） The invention made to solve the above problems is
[A] a polymer component containing a polymer (a) having a structural unit (I) represented by the following formula (1) (hereinafter also referred to as “[A] polymer component”), and [B] a solvent. A composition for forming a liquid immersion upper layer film.

(In Formula (1), R ¹ is a hydrogen atom or a methyl group. R ² and R ³ are each independently a hydrogen atom, a fluorine atom, a hydroxy group, or an alkyl group having 1 to 6 carbon atoms. Provided that R ² and R ³ are not both hydroxy groups, and R ⁴ and R ⁵ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms and bonded to each other. Then, together with the carbon atom to which they are bonded, a ring structure having 3 to 20 carbon atoms may be formed, part or all of the hydrogen atoms of the ring structure may be substituted. It is an integer of 1 to 4. When n is 2 or more, the plurality of R ² and R ³ may be the same or different.

  The composition for forming a liquid immersion upper layer film has high water repellency by containing the polymer (a) having the structural unit (I) represented by the above formula (1) as the [A] polymer component. The liquid immersion upper layer film shown can be formed, and the occurrence of development defects such as bridge defects and blob defects in the resist pattern can be suppressed.

At least one of R ⁴ and R ⁵ in the above formula (1) is preferably a monovalent organic group containing a fluorine atom. When at least one of R ⁴ and R ⁵ is a monovalent organic group having a fluorine atom, a liquid immersion upper film exhibiting higher water repellency can be formed, and a resist pattern bridge defect, blob defect, etc. The occurrence of development defects can be further suppressed.

The monovalent organic group containing a fluorine atom is represented by -R ^E -R ^f , -R ^E -OR ^f or -R ^E -OCOR ^f , and R ^E is a single bond or a divalent linking group, and R ^f Is preferably a fluorinated alkyl group or a hydroxyfluorinated alkyl group. Such an organic group has ^Rf dissociated by an alkali developer, and the fluorine atom content of the [A] polymer component after development is reduced. Therefore, according to the composition for forming a liquid immersion upper layer film, Occurrence of development defects such as defects and blob defects can be further suppressed.

（式（１−１）中、Ｒ^１、Ｒ^２、Ｒ^３及びｎは、上記式（１）と同義である。Ｒ^Ａは、ラクトン環を構成している炭素原子と共に炭素数３〜２０の脂環式炭化水素基を形成する（ｍ＋２）価の基である。但し、上記脂環式炭化水素基は、その構造中に−ＣＯ−、−ＣＯＯ−、−ＯＣＯ−、−Ｏ−、−ＮＲ−、−ＣＳ−、−Ｓ−、−ＳＯ−及び−ＳＯ_２−からなる群より選ばれる少なくとも１種の基を含んでいてもよい。Ｒは、水素原子又は炭素数１〜１０の１価の有機基である。Ｒ^Ｂは、フッ素原子、ヒドロキシ基又は炭素数１〜２０の１価の有機基である。ｍは、１〜６の整数である。ｍが２以上の場合、複数のＲ^Ｂは、同一でも異なっていてもよい。但し、Ｒ^Ｂのうち少なくとも１つは、フッ素原子又はフッ素原子を含む有機基である。） The structural unit (I) is preferably represented by the following formula (1-1).

(In the formula (1-1), R ¹ , R ² , R ³ and n have the same meanings as in the above formula (1). R ^A together with the carbon atom constituting the lactone ring has 3 to 20 carbon atoms. The (m + 2) -valent group that forms an alicyclic hydrocarbon group of the above formula, provided that the alicyclic hydrocarbon group includes —CO—, —COO—, —OCO—, —O—, It may contain at least one group selected from the group consisting of —NR—, —CS—, —S—, —SO— and —SO ₂ —, wherein R is a hydrogen atom or a C 1-10 carbon atom. R ^B is a fluorine atom, a hydroxy group, or a monovalent organic group having 1 to 20 carbon atoms, m is an integer of 1 to 6. When m is 2 or more, the plurality of R ^B, may be the same or different. However, at least one of R ^B is an organic group containing a fluorine atom or a fluorine atom A.)

  By using the structural unit (I) as the specific structural unit, it is possible to form a liquid immersion upper layer film having higher water repellency, and to further develop development defects such as bridge defects and blob defects in the resist pattern. Can be suppressed.

^{R B} in the formula (1-1) is represented by ^{-R E -R f, -R E -OR} f or ^{-R E} -OCOR ^{f, R} E is a single bond or a divalent linking group and ^{R f,} Is preferably a fluorinated alkyl group or a hydroxyfluorinated alkyl group. R ^B in the formula (1-1) is, that it is the specific group, reduction of drainage during development of the immersion upper layer film is formed becomes larger, solubility in an alkali developer of the immersion upper layer film More improved.

（式（１−２）中、Ｒ^１、Ｒ^２、Ｒ^３及びｎは、上記式（１）と同義である。Ｒ^Ｃは、ラクトン環を構成している炭素原子と共に炭素数３〜２０の脂環式炭化水素基を形成する（ｐ＋２）価の基である。但し、上記脂環式炭化水素基は、その構造中に−ＣＯ−、−ＣＯＯ−、−ＯＣＯ−、−Ｏ−、−ＮＲ−、−ＣＳ−、−Ｓ−、−ＳＯ−及び−ＳＯ_２−からなる群より選ばれる少なくとも１種の基を含んでいてもよい。Ｒは、水素原子又は炭素数１〜１０の１価の有機基である。Ｒ^Ｄは、ヒドロキシ基又は炭素数１〜２０の１価の有機基である。ｐは、０〜６の整数である。ｐが２以上の場合、複数のＲ^Ｄは、同一でも異なっていてもよい。但し、Ｒ^Ｄは、フッ素原子を含まない。） The structural unit (I) is also preferably represented by the following formula (1-2).

(In the formula (1-2), R ¹ , R ² , R ³ and n have the same meaning as in the above formula (1). R ^C has 3 to 20 carbon atoms together with the carbon atoms constituting the lactone ring. A (p + 2) -valent group which forms an alicyclic hydrocarbon group of the above-mentioned alicyclic hydrocarbon group, wherein -CO-, -COO-, -OCO-, -O-, It may contain at least one group selected from the group consisting of —NR—, —CS—, —S—, —SO— and —SO ₂ —, wherein R is a hydrogen atom or a C 1-10 carbon atom. ^RD is a hydroxy group or a monovalent organic group having 1 to 20 carbon atoms, p is an integer of 0 to 6. When p is 2 or more, a plurality of R ^D may be the same or different, provided that R ^D does not contain a fluorine atom.

  Even when the structural unit (I) is represented by the above formula (1-2), it is possible to form a liquid immersion upper layer film having high water repellency, and to develop development defects such as a bridge defect and a blob defect in a resist pattern. Occurrence can be suppressed.

（式（２）中、Ｒ^６は、水素原子、メチル基、フッ素原子又はトリフルオロメチル基である。Ｒ^７は、フッ素原子を有する炭素数１〜６の直鎖状若しくは分岐状のアルキル基又はフッ素原子を有する炭素数４〜２０の１価の脂環式炭化水素基である。但し、上記アルキル基及び脂環式炭化水素基が有する水素原子の一部又は全部は置換されていてもよい。） [A] The polymer preferably further has a structural unit (II) represented by the following formula (2) in the same or different polymer as the polymer (a).

(In the formula (2), R ⁶ is a hydrogen atom, a methyl group, a fluorine atom or a trifluoromethyl group. R ⁷ is a C 1-6 linear or branched alkyl group having a fluorine atom. Or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms having a fluorine atom, provided that a part or all of the hydrogen atoms of the alkyl group and alicyclic hydrocarbon group may be substituted. Good.)

  Thus, when the [A] polymer component further has the structural unit (II), the water repellency of the formed liquid immersion upper layer film can be increased.

  [A] The polymer component is at least selected from the group consisting of a structural unit containing a fluorinated sulfonamide group and a structural unit containing an α-trifluoromethyl alcohol group in the same or different polymer as the polymer (a). It is preferable to further have one type of structural unit (III). In the composition for forming a liquid immersion upper film, the [A] polymer component further has the structural unit (III), whereby the removability of the formed liquid immersion upper film can be improved.

  [A] The polymer component preferably further has a structural unit (IV) containing a sulfo group in the same or different polymer as the polymer (a). In the composition for forming a liquid immersion upper layer film, the [A] polymer component further has the structural unit (IV), whereby the removability and the peeling resistance of the formed liquid immersion upper film can be improved.

（式（ｖ）中、Ｒ^８は、水素原子、ハロゲン原子、ニトロ基、アルキル基、１価の脂環式炭化水素基、アルコキシ基、アシル基、アラルキル基又はアリール基である。上記アルキル基、脂環式炭化水素基、アルコキシ基、アシル基、アラルキル基及びアリール基が有する水素原子の一部又は全部は置換されていてもよい。Ｒ^９は、−Ｃ（＝Ｏ）−Ｒ^１０、−Ｓ（＝Ｏ）_２−Ｒ^１１、−Ｒ^１２−ＣＮ又は−Ｒ^１３−ＮＯ_２である。Ｒ^１０及びＲ^１１は、それぞれ独立して、水素原子、アルキル基、フッ素化アルキル基、１価の脂環式炭化水素基、アルコキシ基、シアノ基、シアノメチル基、アラルキル基又はアリール基である。但し、Ｒ^１０又はＲ^１１とＲ^８とが互いに結合して環構造を形成していてもよい。Ｒ^１２及びＲ^１３は、それぞれ独立して、単結合、メチレン基又は炭素数２〜５のアルキレン基である。） [A] The polymer component is at least selected from the group consisting of a structural unit containing a carboxy group and a structural unit containing a group represented by the following formula (v) in the same or different polymer as the polymer (a). It is preferable to further have one type of structural unit (V).

(In the formula (v), R ⁸ 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. The above alkyl group A part or all of hydrogen atoms of the alicyclic hydrocarbon group, alkoxy group, acyl group, aralkyl group and aryl group may be substituted, and R ⁹ is —C (═O) —R ¹⁰ , —S (═O) ₂ —R ¹¹ , —R ¹² —CN or —R ¹³ —NO ₂ , wherein R ¹⁰ and R ¹¹ are each independently a hydrogen atom, an alkyl group, a fluorinated alkyl group, 1 A valent alicyclic hydrocarbon group, an alkoxy group, a cyano group, a cyanomethyl group, an aralkyl group or an aryl group, provided that R ¹⁰ or R ¹¹ and R ⁸ may be bonded to each other to form a ring structure. good ^{.R 12} and ^{R 13} Each, independently, a single bond, a methylene group or an alkylene group having 2 to 5 carbon atoms.)

  In the composition for forming a liquid immersion upper layer film, the [A] polymer component further has the structural unit (V), whereby the removability and the peeling resistance of the formed liquid immersion upper film can be improved.

  [B] The solvent preferably contains an ether solvent. Since the resist film is difficult to dissolve in an ether solvent, the resist film surface is eroded by the solvent in the composition for forming an upper liquid immersion film when the composition for forming the upper liquid film is applied on the resist film. Can prevent the inconvenience. Moreover, since the ether solvent has a low viscosity, the viscosity of the composition for forming a liquid immersion upper layer film can be reduced, and the coating amount can be reduced.

The resist pattern forming method of the present invention comprises:
(1) forming a resist film on the substrate;
(2) forming a liquid immersion upper film on the resist film using the liquid immersion upper film forming composition;
(3) a step of irradiating the resist film on which the liquid immersion upper layer film is laminated with radiation through a photomask to perform liquid immersion exposure; and (4) a step of developing the liquid immersion exposed resist film.

  When the resist pattern forming method is used, development defects such as bridge defects and blob defects can be suppressed, and a resist pattern that is more excellent in pattern shape can be formed.

  Here, the “organic group” refers to a group containing at least one carbon atom.

  The composition for forming a liquid immersion upper film of the present invention can form a liquid immersion upper film exhibiting high water repellency, and can suppress the occurrence of development defects such as bridge defects and blob defects in resist patterns. . Therefore, the composition for forming a liquid immersion upper layer film can be suitably used in a lithography process that requires further miniaturization.

<Composition for forming liquid immersion upper layer film>
The composition for forming an immersion upper layer film of the present invention contains [A] a polymer component and [B] a solvent. Moreover, the said composition for liquid immersion upper film formation may contain arbitrary components in the range which does not impair the effect of this invention. Hereinafter, each component will be described in detail.

<[A] Polymer component>
[A] The polymer component includes a polymer (a) having the structural unit (I) represented by the above formula (1). [A] The polymer component may consist only of the polymer (a), and may contain a polymer (b) having no structural unit (I) in addition to the polymer (a). .

  [A] The polymer component preferably contains a polymer having a fluorine atom. Thereby, the water repellency of the formed liquid immersion upper layer film can be increased. As a form of the polymer having a fluorine atom, the polymer (a) may have a fluorine atom, and the polymer (b) may have a fluorine atom. [A] The polymer component may contain one or more polymers.

  [A] In the polymer (a), in addition to the structural unit (I), the polymer component includes a structural unit (II) represented by the above formula (2), a structural unit containing a fluorinated sulfonamide group, and At least one structural unit (III) selected from the group consisting of structural units containing an α-trifluoromethyl alcohol group, a structural unit (IV) containing a sulfo group, a structural unit containing a carboxy group, and the above formula (v) You may further have at least 1 type of structural unit (V) etc. chosen from the group which consists of a structural unit containing group represented. Moreover, as a polymer (b) which the polymer component [A] may contain, the polymer etc. which have the said structural unit (II)-(V) etc. are mentioned, for example. Hereinafter, each structural unit will be described in detail.

[Structural unit (I)]
The structural unit (I) is a structural unit represented by the above formula (1). When the polymer (a) has the structural unit (I), the liquid immersion upper film forming composition can form a liquid immersion upper film exhibiting high water repellency, and resist pattern bridging defects and blob defects. The occurrence of development defects such as the above can be suppressed.

In said formula (1), R < ¹ > is a hydrogen atom or a methyl group. R ² and R ³ are each independently a hydrogen atom, a fluorine atom, a hydroxy group or an alkyl group having 1 to 6 carbon atoms. However, there is no case where R ² and R ³ are both hydroxy groups. R ⁴ and R ⁵ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, bonded to each other, and a ring having 3 to 20 carbon atoms together with the carbon atom to which they are bonded. A structure may be formed. Some or all of the hydrogen atoms of the ring structure may be substituted. n is an integer of 1 to 4. When n is 2 or more, the plurality of R ² and R ³ may be the same or different.

The alkyl group having 1 to 6 carbon atoms represented by R ² and R ^3, for example a methyl group, an ethyl group, and a n- propyl group.

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by R ⁴ and R ⁵ include a hydrocarbon group having 1 to 20 carbon atoms, —CO—, —COO—, —OCO—, and —O—. , —NR—, —CS—, —S—, —SO—, and —SO ₂ —, a monovalent group composed of at least one group selected from the group consisting of —SO ₂ — and a hydrocarbon group having 1 to 20 carbon atoms. And those having a substituent. However, said R is a hydrogen atom or a C1-C10 monovalent organic group. Examples of the substituent include a fluorine atom, a hydroxy group, a carboxy group, and a cyano group.

  Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms include a linear or branched chain hydrocarbon group, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, and an aromatic group having 6 to 20 carbon atoms. There may be mentioned hydrocarbon groups.

  Examples of the linear or branched chain hydrocarbon group having 1 to 20 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, an octyl group, and a dodecyl group. It is done.

  Examples of the alicyclic hydrocarbon group having 3 to 20 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclooctyl group, and a cyclododecyl group.

  As said C6-C20 aromatic hydrocarbon group, a phenyl group, a tolyl group, a naphthyl group etc. are mentioned, for example.

Examples of the ring structure having 3 to 20 carbon atoms that may be formed by combining R ⁴ and R ⁵ with each other include, for example, cyclopropane structure, cyclobutane structure, cyclopentane structure, cyclohexane structure, cycloheptane structure, cyclooctane structure Monocyclic saturated hydrocarbon structures such as cyclodecane structure, methylcyclohexane structure, and ethylcyclohexane structure;
Monocyclic unsaturated hydrocarbon structures such as cyclobutene structure, cyclopentene structure, cyclohexene structure, cycloheptene structure, cyclooctene structure, cyclodecene structure, cyclopentadiene structure, cyclohexadiene structure, cyclooctadiene structure, cyclodecadiene structure;
Bicyclo [2.2.1] heptane structure, bicyclo [2.2.2] octane structure, tricyclo [5.2.1.0 ^2,6 ] decane structure, tricyclo [3.3.1.1 ^3,7 ] Decane structure, tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] polycyclic saturated hydrocarbon structures such as dodecane structure and adamantane structure;
Bicyclo [2.2.1] heptene structure, bicyclo [2.2.2] octene structure, tricyclo [5.2.1.0 ^2,6 ] decene structure, tricyclo [3.3.1.1 ^3,7 ] Decene structure, tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecene structure and the like, and polycyclic unsaturated hydrocarbon structures and the like, and -CO-, -COO-, -OCO-, -O-, -NR-, -CS- , —S—, —SO—, and —SO ₂ —, which contain at least one group selected from the group consisting of —. R is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms. The ring structure having 3 to 20 carbon atoms which R ⁴ and R ⁵ may be bonded to each other may contain a substituent. Examples of this substituent include a hydroxy group, a carboxy group, and a cyano group.

  Examples of the ring structure composed of -CO- and a hydrocarbon group having 1 to 20 carbon atoms include a cyclic ketone structure having 3 to 8 carbon atoms.

  Examples of the ring structure composed of the -COO- and a hydrocarbon group having 1 to 20 carbon atoms include a lactone structure having 3 to 8 carbon atoms.

  Examples of the ring structure composed of -O- and a hydrocarbon group having 1 to 20 carbon atoms include a cyclic ether structure having 3 to 8 carbon atoms.

  Examples of the ring structure composed of -NR- and a hydrocarbon group having 1 to 20 carbon atoms include a cyclic amine structure having 3 to 8 carbon atoms. Examples of the organic group having 1 to 10 carbon atoms represented by R include a chain hydrocarbon group having 1 to 10 carbon atoms, an aliphatic cyclic hydrocarbon group, an aromatic hydrocarbon group, an epoxy group, a cyano group, and a carboxyl group. Etc.

  Examples of the ring structure composed of -S- and a hydrocarbon group having 1 to 20 carbon atoms include a cyclic thioether structure having 3 to 8 carbon atoms.

  Examples of the ring structure composed of -SO- and a hydrocarbon group having 1 to 20 carbon atoms include a cyclic sulfoxide structure having 3 to 8 carbon atoms.

Examples of the ring structure composed of the —SO ₂ — and the hydrocarbon group having 1 to 20 carbon atoms include a cyclic sulfonyl structure having 3 to 8 carbon atoms.

As the ring structure formed together with the carbon atom to which R ⁴ and R ⁵ are bonded, a 5-membered or 6-membered ring structure is preferable from the viewpoint of ease of synthesis.

  n is preferably 1 or 2, and more preferably 1.

At least one of R ⁴ and R ⁵ in the above formula (1) is preferably a monovalent organic group containing a fluorine atom. When at least one of R ⁴ and R ⁵ in the above formula (1) is a monovalent organic group containing a fluorine atom, a liquid immersion upper film showing higher water repellency can be formed, and a bridge defect of a resist pattern Further, development defects such as blob defects can be further suppressed.

Examples of the monovalent organic group having a fluorine atom include a fluorinated hydrocarbon group having 1 to 20 carbon atoms such as a trifluoromethyl group and a trifluoroethyl group, -CO-, -COO-, -OCO-,- Composed of at least one group selected from the group consisting of O—, —NR—, —CS—, —S—, —SO—, and —SO ₂ —, and a hydrocarbon group having 1 to 20 carbon atoms; Examples thereof include monovalent organic groups in which a part of hydrogen atoms are substituted with at least fluorine atoms, and those having a substituent. Examples of the substituent include a hydroxy group, a carboxy group, and a cyano group. R is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms.

The monovalent organic group containing a fluorine atom is represented by -R ^E -R ^f , -R ^E -OR ^f or -R ^E -OCOR ^f , where R ^E is a single bond or a divalent linking group, and R ^f is preferably a fluorinated alkyl group or a hydroxyfluorinated alkyl group. Such an organic group can form a liquid immersion upper layer film having higher water repellency, and can further suppress development defects such as a bridge defect and a blob defect of a resist pattern.

Examples of the divalent linking group represented by R ^E include a divalent chain hydrocarbon group, a divalent alicyclic hydrocarbon group, a divalent aromatic hydrocarbon group, or a group thereof and —CO. -, - COO -, - OCO -, - O -, - NR -, - CS -, - S -, - SO-, and -SO ₂ - one of the at least one group selected from the group consisting of Or the group which combined 2 or more is mentioned. R is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms.

As the R ^E, a single bond is more preferable.

Examples of the fluorinated alkyl group represented by R ^f include trifluoromethyl group, 2,2,2-trifluoroethyl group, 2,2,3,3,3-pentafluoron-propyl group, 1- Examples thereof include trifluoromethyl-2,2,2-trifluoroethyl group, 2,2,3,3,4,4,4-heptafluoro n-butyl group.

Examples of the hydroxyfluorinated alkyl group represented by R ^f include a 2-hydroxy-2-trifluoromethyl-3,3,3-trifluoropropyl group.

Among these, ^Rf is preferably a trifluoromethyl group, a trifluoroethyl group, or a 2-hydroxy-2-trifluoromethyl-3,3,3-trifluoropropyl group.

  The structural unit (I) is preferably a structural unit represented by the above formula (1-1). When the structural unit (I) is the specific structural unit, the liquid immersion upper layer film-forming composition can form a liquid immersion upper layer film exhibiting higher water repellency, and resist pattern bridging defects, blob defects, etc. The occurrence of development defects can be further suppressed.

In formula (1-1), R ¹ , R ² , R ³ and n have the same meaning as in formula (1). R ^A is a (m + 2) -valent group that forms an alicyclic hydrocarbon group having 3 to 20 carbon atoms together with the carbon atoms constituting the lactone ring. However, the alicyclic hydrocarbon group has —CO—, —COO—, —OCO—, —O—, —NR—, —CS—, —S—, —SO— and —SO _{2 in its structure.} It may contain at least one group selected from the group consisting of-. R is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms. R ^B is a fluorine atom, a hydroxy group, or a monovalent organic group having 1 to 20 carbon atoms. m is an integer of 1-6. When m is 2 or more, the plurality of R ^B may be the same or different. However, at least one of R ^B is a fluorine atom or an organic group containing a fluorine atom.

Examples of the ring structure of the alicyclic hydrocarbon group having 3 to 20 carbon atoms formed by R ^A and the carbon atom constituting the lactone ring include, for example, a cyclopropane structure, a cyclobutane structure, a cyclopentane structure, a cyclohexane structure, Monocyclic saturated hydrocarbon structures such as cycloheptane structure, cyclooctane structure, cyclodecane structure, methylcyclohexane structure, ethylcyclohexane structure;
Monocyclic unsaturated hydrocarbon structures such as cyclobutene structure, cyclopentene structure, cyclohexene structure, cycloheptene structure, cyclooctene structure, cyclodecene structure, cyclopentadiene structure, cyclohexadiene structure, cyclooctadiene structure, cyclodecadiene structure;
Bicyclo [2.2.1] heptane structure, bicyclo [2.2.2] octane structure, tricyclo [5.2.1.0 ^2,6 ] decane structure, tricyclo [3.3.1.1 ^3,7 ] Decane structure, tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecane structure, spiro [4.5] decane structure, spiro [4.4] nonane structure, spiro [3.5] nonane structure, adamantane structure, etc .;
Bicyclo [2.2.1] heptene structure, bicyclo [2.2.2] octene structure, tricyclo [5.2.1.0 ^2,6 ] decene structure, tricyclo [3.3.1.1 ^3,7 ] Decene structure, tetracyclo [6.2.1.1 ^3,6 . 0 ^{2, 7} ] dodecene structure and the like, and polycyclic unsaturated hydrocarbon structures and the like are included, and a carbon-carbon bond in a part of these structures further includes —CO—, —COO—, —OCO—, —O And those containing at least one group selected from the group consisting of —, —NR—, —CS—, —S—, —SO—, and —SO ₂ —. Of these, C3-C20 alicyclic structures, heterocyclic structures, and the like are preferable. R is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms.

The R As the organic group having 1 to 20 carbon atoms represented by ^B, for example, the R ⁴ and same groups containing a fluorine atom in the monovalent organic group having 1 to 20 carbon atoms exemplified as R ^5, etc. Is mentioned.

In addition, it is preferable that m in the said Formula (1-1) is 1. By setting m to 1, the bulkiness of this ring structure containing ^RA can be suppressed, the rigidity of the [A] polymer can be appropriately controlled, and the resolution performance can be further improved.

R ^B in the above formula (1-1) is represented by —R ^E —R ^f , —R ^E —OR ^f , —R ^E —OCOR ^f , and R ^E is a single bond or a divalent linking group; R ^f is preferably a fluorinated alkyl group or a hydroxyfluorinated alkyl group. R ^E is preferably a single bond. The fluorinated alkyl group represented by R ^f is preferably a trifluoromethyl group or a trifluoroethyl group. R ^B in the formula (1-1) is, that it is the specific group, a higher water repellency can be formed an immersion upper layer film exhibiting, and resist pattern bridging defects, development defects such as blob defects Can be further suppressed.

  The structural unit (I) is also preferably a structural unit represented by the above formula (1-2). Even when the structural unit (I) is a structural unit represented by the above formula (1-2), it is possible to form a liquid immersion upper layer film exhibiting high water repellency, and to prevent bridging defects, blob defects, etc. Occurrence of development defects can be suppressed.

In formula (1-2), R ¹ , R ² , R ³ and n have the same meaning as in formula (1). R ^C is a (p + 2) -valent group that forms an alicyclic hydrocarbon group having 3 to 20 carbon atoms together with the carbon atoms constituting the lactone ring. However, the alicyclic hydrocarbon group has —CO—, —COO—, —OCO—, —O—, —NR—, —CS—, —S—, —SO— and —SO _{2 in its structure.} It may contain at least one group selected from the group consisting of-. R is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms. ^RD is a hydroxy group or a monovalent organic group having 1 to 20 carbon atoms. p is an integer of 0-6. When p is 2 or more, the plurality of R ^D may be the same or different. However, ^RD does not contain a fluorine atom. )

Examples of R ^C include the groups exemplified for R ^A in the above formula (1-1).

Examples of ^RD include a group containing no fluorine atom in the organic group having 1 to 20 carbon atoms exemplified by R ⁴ and R ⁵ in the above formula (1-1).

  Examples of the structural unit (I) include structural units represented by the following formulas (I-1) to (I-29).

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

  Among the above structural units, structural units represented by the above formulas (I-1) to (I-8) are preferable, and the formulas (I-1), (I-2), (I-4), (I— 6), structural units represented by (I-7) and (I-8) are more preferred, and structural units represented by formulas (I-4), (I-6) and (I-7) are particularly preferred. preferable.

  [A] The content ratio of the structural unit (I) in the polymer component is preferably 3 mol% or more and 100 mol% or less, and preferably 5 mol% or more and 95 mol% with respect to all the structural units constituting the [A] polymer component. % Or less is more preferable. [A] By setting the content of the structural unit (I) in the polymer component in the above range, a liquid immersion upper layer film having higher water repellency can be formed, and a resist pattern bridge defect, blob defect, etc. The occurrence of development defects can be further suppressed.

  Moreover, as content rate of the structural unit (I) in a polymer (a), 10 mol%-100 mol% are preferable with respect to all the structural units which comprise a polymer (a), 20 mol%-99 mol % Is more preferable, and 30 mol% to 98 mol% is more preferable. By setting the content ratio of the structural unit (I) in the polymer (a) within the above range, a liquid immersion upper layer film exhibiting higher water repellency can be formed, and resist pattern bridging defects, blob defects, etc. The occurrence of development defects can be further suppressed.

[Structural unit (II)]
The structural unit (II) is a structural unit represented by the above formula (2). [A] When the polymer component further has the structural unit (II), the composition for forming a liquid immersion upper layer film can increase the water repellency of the liquid immersion upper layer film to be formed.

In the formula (2), R ⁶ is a hydrogen atom, a methyl group, a fluorine atom or a trifluoromethyl group. R ⁷ is a C 1-6 linear or branched alkyl group having a fluorine atom or a C 4-20 monovalent alicyclic hydrocarbon group having a fluorine atom. However, one part or all part of the hydrogen atom which the said alkyl group and alicyclic hydrocarbon group have may be substituted. Examples of the substituent include a fluorine atom, a hydroxy group, a carboxy group, and an amino group.

Among the linear or branched alkyl groups having 1 to 6 carbon atoms having the fluorine atom represented by R ⁷ , as the linear or branched alkyl group having 1 to 6 carbon atoms, for example, a methyl group , Ethyl group, propyl group, butyl group and the like.

Among the monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms having a fluorine atom represented by R ⁷ , examples of the monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms include a cyclopentyl group. , Cyclopentylpropyl group, cyclohexyl group, cyclohexylmethyl group, cycloheptyl group, cyclooctyl group, cyclooctylmethyl group and the like.

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

In the above formula (2-1) ~ (2-6), ^{R 6} is as defined in the above formula (2).

  Among these, the structural units represented by the above formulas (2-1) and (2-3) are preferable.

  [A] The content ratio of the structural unit (II) in the polymer component is preferably 0 mol% to 50 mol%, preferably 1 mol% to 40 mol, with respect to all structural units constituting the [A] polymer component. % Is more preferable, and 2 mol% to 30 mol% is more preferable. [A] By setting the content ratio of the structural unit (II) in the polymer component within the above range, the water repellency and removability of the liquid immersion upper film formed from the liquid immersion upper film forming composition are further improved. .

  The content ratio of the structural unit (II) in the polymer (a) is preferably 0 mol% to 70 mol%, and preferably 5 mol% to 65 mol% with respect to all the structural units constituting the polymer (a). More preferably, it is more preferably 10 mol% to 60 mol%. By making the content rate of structural unit (II) in a polymer (a) into the said range, the water repellency and removability of the liquid immersion upper film formed from the said composition for liquid immersion upper film formation improve more.

[Structural unit (III)]
The structural unit (III) includes a structural unit containing a fluorinated sulfonamide group (hereinafter also referred to as “structural unit (III-1)”) and a structural unit containing an α-trimethyl alcohol group (hereinafter referred to as “structural unit (III-)”. 2) is also a structural unit selected from the group consisting of: In the composition for forming a liquid immersion upper film, the [A] polymer component has the structural unit (III), whereby the water repellency and removability of the formed liquid immersion upper film are further improved.

  Examples of the structural unit (III-1) include a structural unit represented by the following formula (3-1) (hereinafter also referred to as “structural unit (III-1a)”).

In the formula ^{(3-1), R 14} is a hydrogen atom, a methyl group, a fluorine atom or a trifluoromethyl group. R ⁿ¹ is a divalent linking group. R ⁿ² is a fluorinated alkyl group having 1 to 20 carbon atoms.

R ¹⁴ is preferably a hydrogen atom or a methyl group, and more preferably a methyl group, from the viewpoint of the copolymerizability of the monomer that gives the structural unit (III-1a).

Examples of the divalent linking group represented by R ⁿ¹ include a divalent chain hydrocarbon group having 1 to 6 carbon atoms and a divalent alicyclic hydrocarbon group having 4 to 12 carbon atoms. It is done.

  Examples of the divalent chain hydrocarbon group having 1 to 6 carbon atoms include methanediyl group, 1,2-ethanediyl group, 1,1-ethanediyl group, 1,3-propanediyl group, and 1,2-propane. Diyl 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. Saturated chain hydrocarbon groups, unsaturated chain hydrocarbon groups such as 1,2-ethenediyl group, 1,3-propenediyl group, 1,2-propenediyl group, and the like.

Examples of the divalent alicyclic hydrocarbon group having 4 to 12 carbon atoms include a cyclobutanediyl group such as a 1,3-cyclobutanediyl group; a cyclopentanediyl group such as a 1,3-cyclopentanediyl group; Cyclohexanediyl groups such as 1,4-cyclohexanediyl group and 1,2-cyclohexanediyl group; monocyclic hydrocarbon groups such as cyclooctanediyl group such as 1,5-cyclooctanediyl group;
1,4-norbornanediyl group, norbornanediyl group such as 2,5-norbornanediyl group, polycyclic hydrocarbon group such as 1,3-adamantanediyl group, adamantanediyl group such as 2,4-adamantanediyl group, etc. Is mentioned. Among these, a monocyclic hydrocarbon group is preferable, a cyclohexanediyl group is more preferable, and a 1,2-cyclohexanediyl group is more preferable.

Among these, R ⁿ¹ is preferably a C 1-3 divalent chain hydrocarbon group, more preferably a 1,2-ethanediyl group.

Examples of the fluorinated alkyl group having 1 to 20 carbon atoms represented by R ⁿ² include a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a trifluoroethyl group, a pentafluoromethyl group, a heptafluoropropyl group, and a nona group. A fluorobutyl group etc. are mentioned. Of these, a trifluoromethyl group is preferred.

In the structural unit (III-2), the trifluoromethyl alcohol group means a —C (R) (OH) (CF ₃ ) group (where R is a monovalent organic group). Examples of the structural unit (III-2) include a structural unit represented by the following formula (3-2) (hereinafter also referred to as “structural unit (III-2a)”).

In the formula ^{(3-2), R 15} is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ^t1 is a divalent linking group.

R ¹⁵ is preferably a hydrogen atom or a methyl group, and more preferably a methyl group, from the viewpoint of copolymerizability of the monomer that gives the structural unit (III-2a).

Examples of the divalent linking group represented by R ^t1 include the same groups as those exemplified as R ⁿ¹ in the above formula (3-1). Moreover, the methylene group (—CH ₂ —) in these chain hydrocarbon groups and alicyclic hydrocarbon groups may be substituted with an oxygen atom, a carbonyl group or an ester group. R ^t1 is preferably a divalent chain hydrocarbon group having 1 to 3 carbon atoms, a divalent alicyclic hydrocarbon group having 4 to 12 carbon atoms, a propanediyl group, a divalent group containing a cyclohexane skeleton, A divalent group containing a norbornene skeleton and a divalent group containing an adamantane skeleton are more preferred, and a 1,2-propanediyl group and a 1-cyclohexyl-1,2-ethanediyl group are more preferred.

  Examples of the structural unit (III-2a) include structural units represented by the following formulas (3-2-1) to (3-2-8).

In the formulas (3-2-1) to (3-2-8), R ¹⁵ has the same meaning as the formula (3-2).

  Among these, the structural units represented by the above formulas (3-2-4) and (3-2-8) are preferable.

  [A] The content of the structural unit (III) in the polymer component is preferably 0 mol% to 90 mol%, preferably 1 mol% to 80 mol, based on all structural units constituting the [A] polymer component. % Is more preferable, 4 mol% to 75 mol% is further preferable, and 20 mol% to 70 mol% is particularly preferable. [A] By making the content ratio of the structural unit (III) in the polymer component in the above range, the water repellency and the upper layer removability of the liquid upper layer film formed from the liquid upper layer film forming composition are more improved. improves.

  As a content rate of structural unit (III) in a polymer (a), 0-90 mol% is preferable with respect to all the structural units which comprise a polymer (a), and 0 mol%-85 mol% are more preferable. 0 mol% to 65 mol% is more preferable. By making the content ratio of the structural unit (III) in the polymer (a) within the above range, the water repellency and the upper layer removability of the liquid upper layer film formed from the liquid upper layer film forming composition are further improved. To do.

[Structural unit (IV)]
The structural unit (IV) is a structural unit containing a sulfo group. Examples of the structural unit (IV) include a structural unit represented by the following formula (4).

In the formula (4), R ¹⁶ is a hydrogen atom, a methyl group, a fluorine atom or a trifluoromethyl group. R ^s1 is a single bond, oxygen atom, sulfur atom, divalent chain hydrocarbon group having 1 to 6 carbon atoms, divalent alicyclic hydrocarbon group having 4 to 12 carbon atoms, or 6 to 12 carbon atoms. A divalent aromatic hydrocarbon group or a —C (═O) —X′—R′— group. However, X 'is an oxygen atom, a sulfur atom, or NH group. R ′ is a single bond, a divalent chain hydrocarbon group having 1 to 6 carbon atoms, a divalent alicyclic hydrocarbon group having 4 to 12 carbon atoms, or a divalent aromatic carbon group having 6 to 12 carbon atoms. It is a hydrogen group.

R ¹⁶ is preferably a hydrogen atom or a methyl group from the viewpoint of, for example, the copolymerizability of the monomer that gives the structural unit (IV).

Examples of the divalent chain hydrocarbon group having 1 to 6 carbon atoms and the divalent alicyclic hydrocarbon group having 4 to 12 carbon atoms represented by R ^s1 and R ′ include, for example, the above formula (3- Examples thereof include the same groups as those exemplified as R ^{n1 in} 1).

As a C6-C12 bivalent aromatic hydrocarbon group represented by said ^Rs1 , arylene groups, such as a phenylene group and a tolylene group, etc. are mentioned, for example.

As R ^s1 , a single bond, a divalent chain hydrocarbon group having 1 to 6 carbon atoms, a divalent aromatic hydrocarbon having 6 to 12 carbon atoms, or R ′ is divalent having 1 to 6 carbon atoms. —C (═O) —NH—R ′, which is a chain hydrocarbon group, is preferably a single bond, a methanediyl group, a phenylene group, or —C (═O) —NH—CH (CH ₃ ) —CH ₂ —. more preferably, a single bond, -C (= O) -NH- CH (CH 3) -CH 2 - is more preferred.

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

In the above formulas (4-1) to (4-4), R ¹⁶ has the same meaning as the above formula (4).

  Among these, the structural units represented by the above formulas (4-1) and (4-4) are preferable.

  [A] The content of the structural unit (IV) in the polymer component is preferably 0 mol% to 10 mol%, preferably 0.1 mol% to the total structural unit constituting the [A] polymer component. 5 mol% is more preferable, and 0.2 mol% to 2 mol% is more preferable. [A] By setting the content ratio of the structural unit (IV) in the polymer component in the above range, blob defects can be further suppressed.

  As a content rate of structural unit (IV) in a polymer (a), 0 mol%-20 mol% are preferable with respect to all the structural units which comprise a polymer (a), 0.2 mol%-10 mol % Is more preferable, and 0.5 mol% to 7 mol% is more preferable. A blob defect can be further suppressed by making the content rate of the structural unit (IV) in a polymer (a) into the said range.

[Structural unit (V)]
The structural unit (V) includes a structural unit containing a carboxy group (hereinafter also referred to as “structural unit (V-1)”) and a structural unit containing the group represented by the above formula (v) (hereinafter referred to as “structural unit ( V-2) ") is at least one structural unit selected from the group consisting of: [A] Since the polymer component has the structural unit (V), the composition for forming a liquid immersion upper layer film can improve the removability and the peeling resistance of the liquid immersion upper layer film to be formed.

  As the structural unit (V-1), for example, structural units represented by the following formulas (5-1-1) to (5-1-3) (hereinafter referred to as “structural unit (V-1a)”) Also referred to).

In the above formulas (5-1-1) to (5-1-3), R ¹⁷ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.
In the above formulas (5-1-1) and (5-1-2), R ^c1 and R ^c2 are each independently a divalent chain hydrocarbon group having 1 to 6 carbon atoms and 4 to 4 carbon atoms. 12 divalent alicyclic hydrocarbon groups or divalent aromatic hydrocarbon groups having 6 to 12 carbon atoms.

R ¹⁷ 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 (V-1a).

Examples of the divalent chain hydrocarbon group having 1 to 6 carbon atoms represented by R ^c1 and R ^c2 include the same groups as those exemplified as R ⁿ¹ in the above formula (3-1). Of these, a saturated chain hydrocarbon group is preferred, and a 1,2-ethanediyl group is more preferred.

Examples of the divalent alicyclic hydrocarbon group having 4 to 12 carbon atoms represented by R ^c1 and R ^c2 include groups similar to those exemplified as R ⁿ¹ in the above formula (3-1). . Among these, a monocyclic hydrocarbon group is preferable, a cyclohexanediyl group is more preferable, and a 1,2-cyclohexanediyl group is more preferable.

Examples of the divalent aromatic hydrocarbon group having 6 to 12 carbon atoms represented by R ^c1 and R ^c2 include the same groups as those exemplified as R ^s1 in the above formula (4).

  As the structural unit (V-1a), for example, structural units represented by the following formulas (5-1-1-1) to (5-1-1-3) and the following formula (5-1-2-) Examples thereof include structural units represented by 1) and (5-1-2-2).

In the above formulas (5-1-1-1) to (5-1-2-2), R ¹⁷ has the same meaning as the above formulas (5-1-1) to (5-1-3).

  As the structural unit (V-1a), structural units represented by the above formulas (5-1-1) and (5-1-3) are preferable. Moreover, among the structural units represented by the formula (5-1-1), the structural unit represented by the formula (5-1-1-1) is more preferable.

  The structural unit (V-2) is a structural unit having a group represented by the above formula (v) (hereinafter also referred to as “group (v)”).

In the above formula (v), R ⁸ 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 ⁹ is —C (═O) —R ¹⁰ , —S (═O) ₂ —R ¹¹ , —R ¹² —CN or —R ¹³ —NO ₂ . R ¹⁰ and R ¹¹ 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 ¹⁰ or R ¹¹ and R ⁸ may be bonded to each other to form a ring structure. R ¹² and R ¹³ 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 ⁸ 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 ⁸ 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. Group, branched alkyl groups such as t-butyl group, and the like. As said alkyl group, a C1-C20 alkyl group is preferable.

Examples of the monovalent alicyclic hydrocarbon group represented by R ⁸ include monocyclic alicyclic hydrocarbon groups such as cyclopentyl group and cyclohexyl group; adamantyl group, norbornyl group, tetracyclodecanyl group and the like. Examples include polycyclic alicyclic hydrocarbon groups. As said alicyclic hydrocarbon group, a C3-C20 alicyclic hydrocarbon group is preferable.

Examples of the alkoxy group represented by R ⁸ include a methoxy group and an ethoxy group. As said alkoxy group, a C1-C20 alkoxy group is preferable.

Examples of the acyl group represented by R ⁸ include an acetyl group and a propionyl group. As said acyl group, a C2-C20 acyl group is preferable.

Examples of the aralkyl group represented by R ⁸ include a benzyl group, a phenethyl group, and a naphthylmethyl group. As said aralkyl group, a C7-C12 aralkyl group is preferable.

Examples of the aryl group represented by R ⁸ include a phenyl group, a tolyl group, a dimethylphenyl group, a 2,4,6-trimethylphenyl group, and a naphthyl group. As said aryl group, a C6-C10 aryl group 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 ⁸ may have include a fluorine atom and a chlorine atom. And a halogen atom, a hydroxyl group, a nitro group, a cyano group, and the like.

R ⁸ is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a carbon number from the viewpoint of balancing the developer solubility and peeling resistance of the upper film formed from the immersion upper film forming composition. A 1-5 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 ⁹ is —C (═O) —R ¹⁰ or —S (═O) ₂ —R ¹¹ , the alkyl group represented by R ¹⁰ and R ¹¹ , a monovalent alicyclic hydrocarbon group, or an alkoxy group Examples of the aralkyl group and aryl group include the same groups as those exemplified as the respective groups for R ⁸ . Examples of the fluorinated alkyl group represented by R ¹⁰ and R ¹¹ include groups in which at least one of the hydrogen atoms exemplified as the alkyl group for R ⁸ 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 ¹⁰ or R ¹¹ and R ⁸ to each other includes the carbon atom to which R ¹⁰ or R ¹¹ and R ⁸ are bonded, and having an oxo group. A divalent alicyclic hydrocarbon group of 5 to 12 is preferred.

When R ⁹ is —R ¹² —CN or —R ¹³ —NO ₂ , R ¹² and R ¹³ are preferably a single bond, a methanediyl group or an ethanediyl group.

  As the group (v), groups represented by the following formulas (v-1) to (v-8) are preferable.

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

  Examples of the structural unit (V-2) include structural units derived from (meth) acrylic acid ester derivatives having a group (v), (meth) acrylamide derivatives, vinyl ether derivatives, olefin derivatives, styrene derivatives, and the like. In this, the structural unit derived from a (meth) acrylic acid ester derivative is preferable. That is, as the structural unit (V-2), a structural unit (V-2a) represented by the following formula (5-2) is preferable.

In the formula (5-2), ^{R 8} and ^{R 9} is as defined in the above formula (v). k is an integer of 1 to 3. When k is 2 or more, the plurality of R ⁸ and R ⁹ may be the same or different. L ¹ is a (k + 1) -valent linking group. R ¹⁸ is a hydrogen atom, a methyl group, a fluorine atom or a trifluoromethyl group.

R ¹⁸ 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 (V-2a).

As the (k + 1) -valent linking group represented by L ¹ , for example, as a divalent linking group (when k is 1), an alkanediyl group, a divalent alicyclic hydrocarbon group, an alkenediyl group, And arenediyl groups. 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 methanediyl group, ethanediyl group, propanediyl group, butanediyl group, hexanediyl group, and octanediyl group. As said alkanediyl group, a C1-C8 alkanediyl group is preferable.

  Examples of the divalent alicyclic hydrocarbon group include monocyclic alicyclic hydrocarbon groups such as cyclopentanediyl group and cyclohexanediyl group; polycyclic alicyclic carbon groups such as norbornanediyl group and adamantanediyl group. Hydrogen etc. are mentioned. As said 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. As said alkenediyl group, a C2-C6 alkenediyl group is preferable.

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

Among these, as L ¹ , 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 L ¹ is a divalent alicyclic hydrocarbon group, it is preferable from the viewpoint of improving the water repellency of the obtained upper layer film.

  As the structural unit (V-2a), structural units represented by the following formulas (5-2-1) to (5-2-10) are preferable.

In the formulas (5-2-1) to (5-2-10), R ¹⁸ has the same meaning as the formula (5-2).

  [A] The content ratio of the structural unit (V) in the polymer component is preferably 0 mol% to 30 mol%, preferably 1 mol% to 20 mol, with respect to all the structural units constituting the [A] polymer component. % Is more preferable, and 4 mol% to 15 mol% is more preferable. [A] By making the content rate of the structural unit (V) in a polymer component into the said range, the removability and peeling resistance of the liquid immersion upper film formed from the said composition for liquid immersion upper film formation improve.

  As a content rate of the structural unit (V) in a polymer (a), 0 mol%-60 mol% are preferable with respect to all the structural units which comprise a polymer (a), and 10 mol%-55 mol% are preferable. More preferably, it is more preferably 25 mol% to 50 mol%. By making the content rate of the structural unit (V) in a polymer (a) into the said range, the removability and peeling resistance of the liquid immersion upper film formed from the said composition for liquid immersion upper film formation improve.

[Other structural units]
[A] The polymer component may have other structural units in addition to the structural units (I) to (V) as long as the effects of the present invention are not impaired. As the other structural unit, for example, from the viewpoint of improving water repellency, a structure derived from alkyl (meth) acrylate such as propyl (meth) acrylate, butyl (meth) acrylate, lauryl (meth) acrylate, etc. Examples include units. [A] From the viewpoint of controlling the molecular weight of the polymer component, the glass transition point, the solubility in a solvent, and the like, a structural unit having an acid-dissociable group is exemplified. [A] The content ratio of the other structural units in the polymer component is usually 20 mol% or less and preferably 10 mol% or less with respect to all the structural units constituting the [A] polymer component. As a content rate of the said other structural unit in a polymer (a), it is 20 mol% or less normally with respect to all the structural units which comprise a polymer (a), and 10 mol% or less is preferable.

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

Examples of the solvent used for the polymerization include alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane;
Cycloalkanes such as cyclohexane, cycloheptane, cyclooctane, decalin, norbornane;
Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene;
Halogenated hydrocarbons such as chlorobutanes, bromohexanes, dichloroethanes, hexamethylene dibromide, chlorobenzene;
Saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, i-butyl acetate and methyl propionate;
Ketones such as acetone, 2-butanone, 4-methyl-2-pentanone, 2-heptanone;
Ethers such as tetrahydrofuran, dimethoxyethanes, diethoxyethanes;
Examples include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, and 4-methyl-2-pentanol. In addition, these solvents may use 2 or more types together.

  As reaction temperature in the said superposition | polymerization, it is 40 to 150 degreeC normally, Preferably it is 50 to 120 degreeC. The reaction time is usually 1 hour to 48 hours, preferably 1 hour to 24 hours.

  [A] The weight average molecular weight (Mw) in terms of polystyrene by gel permeation chromatography (GPC) of the polymer component is preferably 2,000 or more and 50,000 or less, more preferably 2,000 or more and 30,000 or less, 5,000 or more and 20,000 or less are more preferable. [A] By making Mw of the polymer component 2,000 or more, water resistance and mechanical properties as a liquid immersion upper layer film can be improved, and by making Mw 50,000 or less, Solubility can be increased. As Mw of a polymer (a), 2,000-50,000 are preferable, 3,000-30,000 are more preferable, 5,000-20,000 are further more preferable. By setting the Mw of the polymer (a) to 2,000 or more, water resistance and mechanical properties as a liquid immersion upper layer film can be improved, and by setting the Mw to 50,000 or less, the polymer can be used with respect to the solvent. Solubility can be increased.

  [A] The ratio (Mw / Mn) of Mw of the polymer component to the number average molecular weight (Mn) in terms of polystyrene by GPC method is preferably 1 to 5, more preferably 1 to 3, and 1 to 2.5. Further preferred. The Mw / Mn of the polymer (a) is preferably 1 to 5, more preferably 1 to 3, and still more preferably 1 to 2.5.

  The liquid immersion upper layer film-forming composition is more preferable as it contains less impurities such as halogen ions and metals. By reducing the impurities, it is possible to improve the coating property as a liquid immersion upper layer film and the uniform solubility in an alkali developer. 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 content of the polymer component is preferably 70% by mass to 100% by mass and more preferably 80% by mass to 100% by mass with respect to the total solid content in the composition for forming an immersion upper layer film. 90 mass% to 100 mass% is more preferable.

<[B] Solvent>
The composition for forming a liquid immersion upper layer film contains a [B] solvent. [B] The solvent can be used as long as it can dissolve or disperse the [A] polymer component and optional components contained as necessary, but the liquid immersion upper layer film-forming composition is formed on the resist film. In the application, those having almost no deterioration in lithography performance due to excessive intermixing with the resist film are preferably used. Two or more of these solvents may be used in combination.

  [B] Examples of the solvent include alcohol solvents, ether solvents, hydrocarbon solvents, ketone solvents, ester solvents, water, and the like.

Examples of alcohol solvents include monohydric alcohols such as butanol and pentanol;
Examples thereof include polyhydric alcohols such as ethylene glycol and propylene glycol.

Examples of ether solvents include partial alkyl ethers of polyhydric alcohols such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether;
Alkyl ethers of polyhydric alcohols such as ethylene glycol dimethyl ether, ethylene glycol methyl ethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether;
Alkyl ether acetates of polyhydric alcohols such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate;
Aliphatic ethers such as diethyl ether, dipropyl ether, dibutyl ether, butyl methyl ether, butyl ethyl ether, diisoamyl ether, hexyl methyl ether, octyl methyl ether, cyclopentyl methyl ether, dicyclopentyl ether;
Aliphatic-aromatic ethers such as anisole and phenylethyl ether;
Examples include cyclic ethers such as tetrahydrofuran, tetrahydropyran, and dioxane.

Examples of hydrocarbon solvents include lower hydrocarbons such as hexane, cyclohexane, heptane;
Higher hydrocarbons such as decane, dodecene, and undecane are listed.

Examples of ketone solvents include dialkyl ketones such as acetone and methyl ethyl ketone;
And cyclic ketones such as cyclopentanone and cyclohexanone.

  Examples of the ester solvent include ethyl acetate and butyl acetate.

  Of these, ether solvents are preferred. [B] When the solvent contains an ether solvent, elution of the resist film component to the liquid immersion upper layer film during the formation of the liquid immersion upper layer film can be suppressed, and intermixing can be reduced. Moreover, since the ether solvent has a low viscosity, the viscosity of the composition for forming a liquid immersion upper layer film can be reduced, and the coating amount can be reduced. As a result, cost can be reduced.

<Optional component>
The composition for forming a liquid immersion upper layer film may contain an optional component in addition to the [A] polymer component and the [B] solvent. As said arbitrary component, surfactant etc. which can improve the applicability | paintability on the resist film of the said composition for liquid immersion upper film formation, etc. are mentioned, for example.

  Examples of the surfactant include commercially available fluorine such as BM-1000, BM-1100 (above, manufactured by BM Chemie), MegaFac F142D, F172, F173, F183 (above, manufactured by Dainippon Ink and Chemicals). And surface active agents. As content of the said surfactant, 5 mass parts or less are preferable with respect to 100 mass parts of [A] polymer components.

<Method for preparing composition for forming liquid immersion upper layer film>
The composition for forming a liquid immersion upper layer film can be prepared, for example, by mixing the [A] polymer component, the [B] solvent and, if necessary, optional components at a predetermined ratio.

  When the composition for forming an immersion upper layer film is prepared as a solution, the ratio of the total amount of the [A] polymer, [B] solvent, and optional components depends on the purpose of use, the required film thickness, etc. Can be set to any density. As solid content concentration of the composition for liquid immersion upper film formation, it is 0.5 mass%-30 mass% normally, and 1 mass%-20 mass% are preferable.

<Resist pattern formation method>
The resist pattern forming method of the present invention comprises:
(1) a step of forming a resist film on the substrate (hereinafter also referred to as “step (1)”),
(2) a step of forming a liquid immersion upper layer film on the resist film using the liquid immersion upper layer film forming composition (hereinafter also referred to as “step (2)”);
(3) a step of irradiating the resist film on which the liquid immersion upper layer film is laminated with a radiation through a photomask to perform liquid immersion exposure (hereinafter also referred to as “step (3)”); and (4) the liquid immersion Step of developing the exposed resist film (hereinafter also referred to as “step (4)”)
Have

  According to the resist pattern forming method, since the liquid immersion upper layer film forming composition is used, a liquid immersion upper layer film exhibiting high water repellency can be formed, and the resist pattern has a bridge defect, a blob defect, etc. The occurrence of development defects can be suppressed. Hereinafter, each process is explained in full detail.

[Step (1)]
In this step, a photoresist composition is applied on the substrate to form a resist film. As the substrate, for example, a conventionally known substrate such as a silicon wafer or a wafer coated with aluminum can be used. Further, for example, an organic or inorganic lower antireflection film disclosed in Japanese Patent Publication No. 6-12452, Japanese Patent Application Laid-Open No. 59-93448, etc. may be formed on the substrate.

  Examples of the photoresist composition include a positive-type or negative-type chemically amplified resist composition containing an acid generator, a positive-type resist composition comprising an alkali-soluble resin and a quinonediazide-based photosensitizer, and an alkali-soluble resin and a crosslinking agent. And negative resist compositions composed of an agent. A commercially available photoresist composition can also be used as the photoresist composition. Although it does not specifically limit as a coating method of a photoresist composition, For example, it can apply | coat by well-known methods, such as a spin coat method. In addition, when apply | coating a photoresist composition, the quantity of the photoresist composition to apply | coat is adjusted so that the resist film formed may become a desired film thickness. The thickness of the resist film to be formed is usually 0.01 μm to 1 μm, preferably 0.01 μm to 0.5 μm.

  After applying the photoresist composition on the substrate, the solvent in the coating film may be volatilized by pre-baking (hereinafter also referred to as “PB”) in order to volatilize the solvent. The heating conditions for PB are appropriately selected depending on the composition of the photoresist composition, but are usually about 30 ° C to 200 ° C, preferably 50 ° C to 150 ° C.

[Step (2)]
In this step, the liquid immersion upper layer film-forming composition is applied onto the resist film to form a liquid immersion upper layer film. In this step, it is preferable that the liquid immersion upper layer film forming composition is applied and then baked. Since the immersion medium and the resist film are not in direct contact with each other by this baking, the lithography performance of the resist film due to the immersion medium penetrating into the resist film is deteriorated or the components eluted from the resist film into the immersion medium This effectively prevents the lens of the projection exposure apparatus from being contaminated. As a method for forming the liquid immersion upper layer film, a method similar to the method for forming the resist film can be employed except that the liquid immersion upper layer film forming composition is used instead of the photoresist composition. .

  The thickness of the immersion upper layer film is preferably as close as possible to an odd multiple of λ / 4m (where λ is the wavelength of radiation and m is the refractive index of the protective film). By doing in this way, the reflection suppression effect in the upper interface of a resist film can be enlarged.

[Step (3)]
In this step, an immersion medium is disposed between the immersion upper layer film and the lens, and the resist film and the immersion upper layer film are irradiated with radiation through the immersion medium and a mask having a predetermined pattern, The resist film and the liquid immersion upper layer film are exposed.

  As the immersion medium, a liquid having a higher refractive index than air is usually used. Specifically, water is preferably used, and pure water is more preferably used. In a state where the immersion medium is interposed, that is, in a state where the immersion medium is filled between the lens and the immersion upper layer film, radiation is irradiated from the exposure apparatus, and the resist film is passed through a mask having a predetermined pattern. And exposing the liquid immersion upper layer film.

  Examples of the radiation include visible light; ultraviolet rays such as g rays and i rays; far ultraviolet rays such as excimer lasers; X rays; Among these, an ArF excimer laser (wavelength 193 nm) and a KrF excimer laser (wavelength 248 nm) are preferable. Irradiation conditions such as radiation dose can be appropriately set according to the resist composition, the composition for forming an immersion upper layer film, and the like.

  Post exposure baking (PEB) is preferably performed after exposure. By performing PEB, the dissociation reaction of the acid dissociable group in the photoresist composition can proceed smoothly. As a heating condition of PEB, it is 30 degreeC-200 degreeC normally, and 50 degreeC-170 degreeC is preferable.

[Step (4)]
In this step, the exposed resist film and immersion upper layer film are developed with a developing solution to form a resist pattern. Since the liquid immersion upper film is formed from the composition for forming the liquid immersion upper film, the liquid immersion upper film can be easily removed with a developer, and a special process for removing the liquid immersion upper film is required. And not.

  Examples of the developer include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, dimethylethanolamine. , Triethanolamine, tetraalkylammonium hydroxide (TMAH), tetraalkylammonium hydroxides such as tetraethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene An alkaline aqueous solution in which at least one alkaline compound such as 1,5-diazabicyclo- [4.3.0] -5-nonane is dissolved is preferable. Among these, tetraalkylammonium hydroxide aqueous solutions are more preferable.

  An appropriate amount of a water-soluble organic solvent such as alcohols such as methanol and ethanol, and a surfactant can be added to the developer. In addition, when developing using alkaline aqueous solution, it is preferable to wash with water after image development, and you may dry after washing with water.

  In order to improve the resolution and the like of the resist film, it is preferable to perform baking (hereinafter also referred to as “PEB”) after development after exposure. The baking temperature can be appropriately set depending on the resist composition to be used, the composition for forming a liquid immersion upper layer film, and the like, but is preferably 30 to 200 ° C, more preferably 50 to 150 ° C.

  EXAMPLES Hereinafter, although this invention is explained in full detail based on an Example, this invention is not limited to this Example. The measuring method of various physical property values is shown below.

[ ¹ H-NMR analysis and ¹³ C-NMR analysis]
¹ H-NMR analysis of the compound and ¹³ C-NMR analysis of the polymer were performed using a nuclear magnetic resonance apparatus (JNM-EX400, manufactured by JEOL Ltd.), using CDCl ₃ as a measurement solvent, and tetramethylsilane (TMS). Measured as an internal standard.

[Mw and Mn measurement]
Mw and Mn of the polymer were measured by gel permeation chromatography (GPC) under the following conditions.

Column: 2 G2000HXL, 1 G3000HXL, and 1 G4000HXL (manufactured by Tosoh)
Mobile phase: Tetrahydrofuran Column temperature: 40 ° C
Flow rate: 1.0 mL / min Detector: Differential refractometer Standard material: Monodisperse polystyrene

<Synthesis of monomer>
[Synthesis Example 1]
To a dry 1 L three-neck reactor equipped with a dropping funnel and a condenser, 13.1 g (200 mmol) of zinc powder (manufactured by Aldrich, particle diameter of 150 μm or less) was added, and after making the nitrogen atmosphere, 240 mL of tetrahydrofuran (THF) was added. While stirring with a magnetic stirrer, 1.9 mL (15 mmol) of chlorotrimethylsilane was added, and the mixture was stirred at 20 ° C. to 25 ° C. for 30 minutes. A solution prepared by dissolving 33.2 g (200 mmol) of hexafluoroacetone in 40 mL of THF was added thereto. Next, a solution of 34.8 g (180 mmol) of ethyl (2-bromomethyl) acrylate in 50 mL of THF was added dropwise. After dropping, the mixture was stirred at room temperature for 2 hours. After confirming the completion of the reaction by gas chromatography, an aqueous ammonium chloride solution and ethyl acetate were added to separate the layers. The obtained organic layer was washed successively with water and saturated brine. Thereafter, the organic layer was dried and concentrated under reduced pressure. Thereafter, purification by column chromatography was performed to synthesize 14.9 g of a compound represented by the following formula (S-1) (64 mmol, yield 32%).

¹ H-NMR data is shown below.
¹ H-NMR (CDCl ₃ ) δ: 2.21-2.43 (m, 2H), 5.51-5.61 (m, 1H), 6.00-6.18 (m, 1H)

[Synthesis Example 2]
In Synthesis Example 1, except that 33.2 g of 4-trifluoromethylcyclohexanone was used instead of 33.2 g of hexafluoroacetone, the same operation as in Synthesis Example 1 was carried out, and represented by the following formula (S-2). 31.9 g of the above compound was synthesized (136 mmol, yield 68%).

¹ H-NMR data is shown below.
¹ H-NMR (CDCl ₃ ) δ: 1.53-2.11 (m, 8H), 2.16-2.31 (m, 1H), 2.70 (t, J = 2.8 Hz, 1H) 2.75 (t, J = 2.8 Hz, 1H), 5.60-5.65 (m, 1H), 6.20-6.27 (m, 1H)

[Synthesis Example 3]
First, 1,004 g (8.64 mol) of 1,4-cyclohexanediol was added to a 20 L reactor, and 4,320 mL of THF was added thereto, followed by stirring with a mechanical stirrer. To the reactor was added 21.71 g (86.39 mmol) of pyridinium p-toluenesulfonate, followed by 726.73 g (8.64 mol) of 3,4-dihydro-2H-pyran and allowed to react at room temperature for 12 hours. Thereafter, 17.28 g (170.77 mmol) of triethylamine was added to stop the reaction, and the mixture was concentrated. The concentrated solution was partitioned between hexane and water, and NaCl was added to the obtained aqueous layer until saturation, followed by extraction with methylene chloride. The obtained organic layer was dried over magnesium sulfate and then concentrated under reduced pressure to synthesize 737 g of a compound represented by the following formula (S-3-A) (3.68 mol, yield 43%).

¹ H-NMR data is shown below.
¹ H-NMR (CDCl ₃ ) δ: 1.24-1.91 (m, 13H), 1.94-2.05 (m, 2H), 3.45-3.53 (m, 1H), 3 .59-3.70 (m, 1H), 3.71-3.78 (m, 1H), 3.87-3.95 (m, 1H), 4.67-4.71 (m, 1H)

  Next, 300 g (1.5 mol) of the above synthesized (S-3-A) was added to a 5 L three-necked reactor, to which 1,200 mL of methylene chloride and 0.228 g of 2-azaadamantane-N-oxyl ( 1.5 mmol), 17.85 g (150 mmol) of potassium bromide, and 450 mL of a saturated aqueous sodium hydrogen carbonate solution were sequentially added, and the mixture was stirred with a mechanical stirrer. The reactor was cooled to 0 ° C., and a solution prepared by mixing 1,913 g of a 7 mass% sodium hypochlorite aqueous solution and 450 mL of a saturated sodium hydrogen carbonate aqueous solution was added dropwise over 3 hours. After completion of dropping, the mixture was stirred at 0 ° C. for 30 minutes, and then 100 mL of a saturated aqueous sodium thiosulfate solution was added to stop the reaction and liquid separation was performed. The obtained organic layer was washed with saturated brine, dried over magnesium sulfate and concentrated under reduced pressure to synthesize 214 g of the compound represented by the following formula (S-3-B) (1.08 mol, yield 72). %).

¹ H-NMR data is shown below.
¹ H-NMR (CDCl ₃ ) δ: 1.51-2.16 (m, 10H), 2.22-2.35 (m, 2H), 2.50-2.69 (m, 2H), 3 .49-3.56 (m, 1H), 3.88-3.95 (m, 1H), 4.05-4.11 (m, 1H), 4.74-4.78 (m, 1H)

  Subsequently, the same procedure as in Synthesis Example 1 was carried out except that 39.7 g of (S-3-B) synthesized above was used in place of 33.2 g of hexafluoroacetone in Synthesis Example 1, and the resulting crude After the product was dissolved in 500 mL of ethanol, 9.51 g (50 mmol) of paratoluenesulfonic acid monohydrate was added and reacted at room temperature for 3 hours. This was extracted with methylene chloride, washed with water and saturated brine, and then purified by column chromatography to synthesize 25.1 g of a compound represented by the following formula (S-3) (138 mmol, yield 69). %).

¹ H-NMR data is shown below.
¹ H-NMR (CDCl ₃ ) δ: 1.55-2.09 (m, 8H), 2.72 (t, J = 2.8 Hz, 1H), 2.76 (t, J = 2.8 Hz, 1H), 3.67-3.77 (m, 0.5H), 3.96-4.04 (m, 0.5H), 5.62-5.68 (m, 1H), 6.22- 6.28 (m, 1H)

[Synthesis Example 4]
Under a nitrogen atmosphere, 18.2 g (100 mmol) of (S-3) synthesized above was added to a 500 mL three-necked reactor, and 100 mL of methylene chloride was added thereto. After the reactor was cooled to 0 ° C., 23.1 g (110 mmol) of trifluoroacetic anhydride was added dropwise over 15 minutes. After completion of dropping, the mixture was stirred at 0 ° C. for 2 hours, and 300 mL of saturated aqueous sodium hydrogen carbonate solution was added to stop the reaction and liquid separation was performed. The obtained organic layer was washed with saturated brine, dried over magnesium sulfate, concentrated under reduced pressure, and purified by column chromatography to synthesize 19.7 g of a compound represented by the following formula (S-4). (70.8 mmol, 71% yield).

¹ H-NMR data is shown below.
¹ H-NMR (CDCl ₃ ) δ: 1.62-2.01 (m, 8H), 2.22 (s, 3H), 2.75-2.89 (m, 2H), 4.81-4 .95 (m, 0.5H), 5.02-5.16 (m, 0.5H), 5.64-5.72 (m, 1H), 6.27-6.33 (m, 1H)

[Synthesis Example 5]
In Synthesis Example 4, the procedure is the same as in Synthesis Example 4 except that 11.2 g of acetic anhydride is used instead of 23.1 g of trifluoroacetic anhydride, and represented by the following formula (S-5). 16.0 g of compound was synthesized (71.4 mmol, 71% yield).

¹ H-NMR data is shown below.
¹ H-NMR (CDCl ₃ ) δ: 1.40-1.90 (m, 8H), 2.00-2.4 (m, 5H), 5.50-6.00 (m, 1H), 6 .10-6.50 (m, 1H)

[Synthesis Example 6]
In Synthesis Example 4, the same procedure as in Synthesis Example 4 was performed except that 23.8 g of 3,3,3-trifluoropropionic anhydride was used instead of 23.1 g of trifluoroacetic anhydride. 14.9 g of a compound represented by (S-6) was synthesized (51.0 mmol, yield 51%).

¹ H-NMR data is shown below.
¹ H-NMR (CDCl ₃ ) δ: 1.61-2.00 (m, 8H), 2.61-2.91 (m, 4H), 4.86-4.99 (m, 0.5H) , 5.06-5.19 (m, 0.5H), 5.63-5.70 (m, 1H), 6.21-6.30 (m, 1H)

[Synthesis Example 7]
First, in Synthesis Example 4, except that 16.6 g of 5-hydroxyadamantan-2-one was used instead of 18.2 g of (S-3), the same operation as in Synthesis Example 4 was performed. 22.0 g of the compound represented by -7-A) was synthesized (83.9 mmol, 84% yield).

¹ H-NMR data is shown below.
¹ H-NMR (CDCl ₃ ) δ: 1.13-2.69 (m, 13H)

  Next, in Synthesis Example 1, instead of 33.2 g of hexafluoroacetone, except that 52.4 g of (S-7-A) synthesized above was used, the same operation as in Synthesis Example 1 was performed, and the following formula ( 21.8 g of the compound represented by S-7) was synthesized (66.0 mmol, yield 33%).

¹ H-NMR data is shown below.
¹ H-NMR (CDCl ₃ ) δ: 1.10-2.68 (m, 13H), 2.77-2.91 (m, 2H), 5.63-5.70 (m, 1H), 6 .21-6.30 (m, 1H)

[Synthesis Example 8]
In Synthesis Example 1, 4,4,4-trifluoro-3-hydroxy-3-trifluoromethylbutanal synthesized according to the literature (Chemische Berichte 1986, 119, 3502-3506) instead of 33.2 g of hexafluoroacetone Except for using 45.0 g, the same operation as in Synthesis Example 1 was performed to synthesize 11.8 g of a compound represented by the following formula (S-8) (42.4 mmol, yield 21%).

¹ H-NMR data is shown below.
¹ H-NMR (CDCl ₃ ) δ: 1.55-1.65 (m, 3H), 2.35-2.65 (m, 2H), 2.75-3.05 (m, 1H), 3 .10-3.45 (m, 1H), 5.55-5.75 (m, 1H), 6.00-6.20 (m, 1H)

<[A] Synthesis of polymer component>
[A] Each monomer used for the synthesis of the polymer (a) and the polymer (b) constituting the polymer component is shown below.

  Monomers (S-1) to (S-8) are structural units (I), monomers (M-4) and (M-5) are structural units (II), monomers ( M-1) to (M-3) are structural units (III), monomers (M-6) and (M-7) are structural units (IV), monomers (M-8) and (M-8) M-9) gives structural units (V), respectively.

<Synthesis of polymer (a)>
[Synthesis Example 9]
A polymerization initiator solution was prepared by dissolving 0.7 g of dimethyl 2,2-azobis (2-methylpropionate) as a polymerization initiator in 0.7 g of methyl ethyl ketone. Meanwhile, in a 200 mL three-necked flask equipped with a thermometer and a dropping funnel, 6.1 g (50 mol%) of the monomer (S-1) and 10.6 g (50 mol%) of the monomer (M-1). , And 19.3 g of methyl ethyl ketone were added and purged with nitrogen for 30 minutes. After purging with nitrogen, the flask was heated to 75 ° C. while stirring with a magnetic stirrer. Subsequently, using the dropping funnel, the polymerization initiator solution prepared above was dropped over 5 minutes and aged for 360 minutes. Then, it cooled to 30 degrees C or less, and obtained the polymerization reaction liquid.

Subsequently, after concentrating the obtained polymerization reaction liquid to 40 g, it moved to the separatory funnel. The separation funnel was charged with 44 g of methanol and 220 g of n-hexane to carry out separation purification. After separation, the lower layer solution was recovered. Into the recovered lower layer liquid, 220 g of n-hexane was added to carry out liquid separation purification. After separation, the lower layer solution was recovered. The recovered lower layer solution was replaced with 4-methyl-2-pentanol to obtain a solution containing the polymer (a-1). 0.5 g of the polymer solution was placed on an aluminum dish, and the solid content concentration of the solution containing the polymer (a-1) was calculated from the mass of the residue after heating for 30 minutes on a hot plate heated to 155 ° C. Then, the value of the solid content concentration was used for the subsequent preparation of the composition for forming the upper layer film and the yield calculation. The obtained polymer (a-1) had Mw of 10,000, Mw / Mn of 2.1, and the yield was 75%. ^{As a result of 1} H-NMR, ¹³ C-NMR and ¹⁹ F-NMR analyses, the content ratio of the structural unit (I) and the content ratio of the structural unit (III) were 50 mol% and 50 mol%, respectively. .

[Synthesis Examples 10 to 16]
Each polymer was synthesized in the same manner as in Synthesis Example 9 except that the types and amounts of monomers shown in Table 1 were used. Table 1 shows the yield (%), Mw, and Mw / Mn of each polymer synthesized. “-” Indicates that the corresponding monomer was not used.

<Synthesis of polymer (b)>
[Synthesis Example 17]

  19.0 g (85 mol%) of the monomer (M-1) and 0.8 g of dimethyl 2,2-azobis (2-methylpropionate) as a polymerization initiator were dissolved in 20.0 g of isopropanol. A monomer solution was prepared. On the other hand, 20 g of isopropanol was put into a 200 mL three-necked flask equipped with a thermometer and a dropping funnel, and purged with nitrogen for 30 minutes. After purging with nitrogen, the inside of the flask was heated to 80 ° C. while stirring with a magnetic stirrer. Then, using the dropping funnel, the monomer solution prepared above was dropped over 2 hours. After completion of the dropwise addition, the reaction was further continued for 1 hour, and then 2 g of an isopropanol solution of 1.0 g (15 mol%) of monomer (M-7) was added dropwise over 30 minutes. Then, after reacting further for 1 hour, it cooled to 30 degrees C or less, and obtained the polymerization reaction liquid.

The resulting polymerization reaction solution was concentrated to 44 g and then transferred to a separatory funnel. The separation funnel was charged with 44 g of methanol and 264 g of n-hexane, and separated and purified. After separation, the lower layer solution was recovered. This lower layer solution was again transferred to a separatory funnel. Thereafter, 264 g of n-hexane was put into the above separatory funnel, separation and purification were performed, and the lower layer liquid was recovered after separation. The recovered lower layer solution was replaced with 4-methyl-2-pentanol, and the total amount was adjusted to 80 g. After the preparation, 80 g of water was added for separation and purification. After separation, the upper layer liquid was recovered. The recovered upper layer liquid was substituted with 4-methyl-2-pentanol to obtain a solution containing the polymer (b-1). Mw of the obtained polymer (b-1) was 10,000, Mw / Mn was 1.7, and the yield was 80%. Moreover, the content rate of each structural unit derived from (M-1) and (M-7) was 98 mol% and 2 mol%, respectively.
[Synthesis Examples 18 and 20-22]

  Polymers (b-2) and (b-4) to (b-6) were synthesized in the same manner as in Synthesis Example 17 except that the types and amounts of monomers shown in Table 2 were used.

[Synthesis Example 19]
A polymer (b-3) was synthesized in the same manner as in Synthesis Example 9 except that the types and amounts of monomers shown in Table 2 were used.

  Table 2 shows the yield, Mw, and Mw / Mn of each of the synthesized polymers (b). “-” Indicates that the corresponding monomer was not used.

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

[[B] solvent]
B-1: 4-Methyl-2-pentanol B-2: Diisoamyl ether

[Example 1]
[A] (a-1) 20 parts by mass and (b-1) 80 parts by mass as polymer components, and [B] (B-1) 1,000 parts by mass and (B-2) 4 as solvents. 1,000 parts by mass were mixed to prepare a composition for forming a liquid immersion upper layer film.

[Examples 2 to 14]
Except having mixed each component of the kind and quantity shown in Table 3, it operated like Example 1 and prepared each composition for liquid immersion upper film formation.

<Preparation of photoresist composition>
A photoresist composition for forming a resist film was prepared by the following method.

[[P] Synthesis of polymer for photoresist composition]
[P] Monomers used for the synthesis of the polymer for the photoresist composition are shown below.

[Synthesis Example 23]
The above compound (r-1) 53.93 g (50 mol%), compound (r-2) 35.38 g (40 mol%), compound (r-3) 10.69 g (10 mol%) was converted into 2-butanone 200 g. A monomer solution in which 5.58 g of dimethyl 2,2′-azobis (2-methylpropionate) was further dissolved was prepared. A 500 mL three-necked flask charged with 100 g of 2-butanone was purged with nitrogen for 30 minutes. After the nitrogen purge, the reaction kettle was heated to 80 ° C. with stirring, and the monomer solution prepared above was added dropwise 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 reaction, the polymerization solution was cooled with water and cooled to 30 ° C. or lower. The cooled polymerization solution was put into 2,000 g of methanol, and the precipitated white powder was filtered off. The filtered white powder was washed twice with 400 g of methanol, filtered, and dried at 50 ° C. for 17 hours to synthesize a white powder polymer (P-1) (74 g, yield 74%). ). Mw of the polymer (P-1) was 6,900, and Mw / Mn was 1.70. Moreover, as a result of ¹³ C-NMR analysis, the content ratio of each structural unit derived from (r-1), (r-2) and (r-3) was 53.0 mol%, 37.2 mol%, respectively. And 9.8 mol%.

<Preparation of photoresist composition (α)>
The [Q] acid generator, [R] acid diffusion controller and [S] solvent used for the preparation of the photoresist composition (α) are shown below.

[[Q] acid generator]
Q-1: Triphenylsulfonium nonafluoro-n-butanesulfonate Q-2: 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium nonafluoro-n-butanesulfonate

[[R] acid diffusion controller]
R-1: R-(+)-(t-butoxycarbonyl) -2-piperidinemethanol

[[T] solvent]
T-1: Propylene glycol monomethyl ether acetate T-2: Cyclohexanone T-3: γ-Butyrolactone

[Synthesis Example 24]
[P] 100 parts by mass of (P-1) polymer, [Q] 1.5 parts by mass and (Q-2) 6 parts by mass of acid generator, and [R] acid diffusion 0.65 parts by mass of (R-1) as a control agent is mixed, and (T-1) 2,900 parts by mass, (T-2) 1,250 parts by mass as a [T] solvent and (T-3) A photoresist composition (α) was prepared by adding 100 parts by mass, adjusting the total solid content concentration to 5% by mass, and filtering through a filter having a pore diameter of 30 nm.

<Evaluation>
Various evaluations shown below were performed on the composition for forming a liquid immersion upper layer film of the above example. The evaluation results are shown in Table 3 below.

[Composition stability]
The presence / absence of white turbidity of the composition for forming a liquid immersion upper layer film was evaluated. After stirring the composition for forming a liquid immersion upper layer film for 30 minutes, the presence or absence of cloudiness was visually observed. The composition stability was evaluated as “◯” when no white turbidity was observed, and “×” when white turbidity was observed.

[Removability of upper layer film]
The removability of the immersion upper layer film with an alkaline developer was evaluated. A coating / development apparatus (CLEAN TRACK ACT8, manufactured by Tokyo Electron Co., Ltd.) spin-coats the composition for forming a liquid immersion upper layer film on an 8-inch silicon wafer, performs PB for 60 seconds at 90 ° C., and performs liquid immersion with a film thickness of 90 nm. An upper layer film was formed. The film thickness was measured using a film thickness measuring device (Lambda Ace VM90, manufactured by Dainippon Screen). This liquid immersion upper layer film was subjected to paddle development for 60 seconds using a 2.38 mass% TMAH aqueous solution as a developer with the above coating / developing apparatus, spin-dried by shaking, and the wafer surface was observed. The upper layer film removability was evaluated as “◯” when no residue was observed, and “x” when the residue was observed.

[Backward contact angle]
The value of the receding contact angle of water on the surface of the liquid immersion upper layer was measured. A composition for forming a liquid immersion upper 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 a liquid immersion upper film having a thickness of 30 nm. Thereafter, using a contact angle meter (DSA-10, manufactured by KRUS), the receding contact angle was measured promptly under the environment of room temperature 23 ° C., humidity 45%, normal pressure by the following procedure. 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 can 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 withdrawn from the water droplet, and the needle was pulled down to the initial position again 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 (°)). The measured values of the receding contact angle are shown in Table 3 below.

[Elution volume]
The amount of elution of the resist film component from the resist film on which the immersion upper layer film was formed was evaluated. Silicon centered on a circular shape with a diameter of 11.3 cm at the center on an 8-inch silicon wafer that has been subjected to hexamethyldisilazane (HMDS) treatment (100 ° C. for 60 seconds) with the above coating / developing apparatus. A rubber sheet (made of Kureha elastomer, thickness 1.0 mm, square of 30 cm on one side) was placed. 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, apart from the silicon wafer, an 8-inch silicon wafer on which a lower antireflection film, a resist film and a liquid immersion upper film are formed is prepared, and the liquid immersion upper film is positioned on the silicon rubber sheet side. That is, in other words, the ultra-pure water was placed so as not to leak while contacting the immersion upper layer film and the ultra-pure water. The silicon wafer on which the lower antireflection film, the resist film, and the liquid immersion upper film are formed is obtained by applying the lower antireflection film composition (ARC29A, manufactured by Brewer Science) on the 8-inch silicon wafer. The lower layer antireflection film having a film thickness of 77 nm is formed by spin coating, and then the photoresist composition (α) is spin coated on the lower layer antireflection film using the coating / developing apparatus. Then, a resist film having a film thickness of 205 nm is formed by baking at 115 ° C. for 60 seconds. After that, a composition for forming a liquid immersion upper film is applied onto this resist film, PB is applied at 90 ° C. for 60 seconds, and a film thickness of 30 nm is formed. It was obtained by forming a liquid immersion upper layer film.

  After placing the liquid immersion upper layer film, this 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.

Subsequently, the peak intensity of the anion part of the photoacid generator in the ultrapure water obtained above was measured using a liquid chromatograph-mass spectrometer (LC-MS) (LC part: SERIES 1100 (manufactured by AGILENT), MS part: Mariner (Perseptive Biosystems, Inc.)) under the following measurement conditions. At that time, a calibration curve was prepared by measuring the peak intensities of the 1 ppb, 10 ppb, and 100 ppb aqueous solutions of the photoacid generator used in the photoresist composition (α) under the following measurement conditions. The amount of elution was calculated from the peak intensity. Further, the amount of elution was measured in the same manner for the acid diffusion controller. When these elution amounts were 5.0 × 10 ⁻¹² mol / cm ² or less, the resist composition elution suppression performance was “◯”, which was larger than 5.0 × 10 ⁻¹² mol / cm ^2. And evaluated as “x”.

(Measurement condition)
Column used: CAPCELL PAK MG (manufactured by Shiseido), 1 Flow rate: 0.2 mL / min Outflow solvent: Water / methanol (3/7) with 0.1% by mass of formic acid Measurement temperature: 35 ° C.

[Peeling resistance]
The difficulty of peeling the liquid immersion upper layer film from the substrate was evaluated. As the substrate, an 8-inch silicon wafer not subjected to HMDS treatment was used. A liquid immersion upper layer film-forming composition was spin-coated on the substrate by the coating / developing apparatus, and then subjected to PB at 90 ° C. for 60 seconds to form a 30 nm-thick coating film (immersion upper layer film). Thereafter, rinsing with pure water was performed for 60 seconds in the coating / developing apparatus, followed by drying by shaking. As for peeling resistance, when peeling of the liquid immersion upper layer film is recognized over the entire wafer surface after rinsing, it is indicated as `` X '', and when peeling is recognized only at the edge part, `` ○ '' is completely recognized. The case where there was not was evaluated as "◎".

[Pattern shape]
The goodness of the pattern shape of the resist pattern formed from the resist film on which the liquid immersion upper layer film was formed was evaluated. An underlayer antireflection film-forming composition (ARC29A, manufactured by Brewer Science) is applied to a 12-inch silicon wafer substrate to form a 77 nm-thick underlayer antireflection film, and then a photoresist composition (α) is spun. After coating, a resist film having a film thickness of 150 nm is formed by performing PB at 115 ° C. for 60 seconds, and then a liquid immersion upper film forming composition is applied on the resist film, and PB is performed at 90 ° C. for 60 seconds. As a result, a liquid immersion upper layer film having a thickness of 30 nm was formed. Next, the formed resist film is exposed through a mask pattern for forming a line and space pattern (1L / 1S) having a line width of 60 nm using an ArF excimer laser immersion exposure apparatus (S610C, manufactured by NIKON). went. Next, after performing PEB at 115 ° C. for 60 seconds, a 2.38 mass% TMAH aqueous solution was used as a developing solution, developed at 23 ° C. for 60 seconds, washed with water, and dried to form a positive resist pattern. At this time, the exposure amount at which a line and space pattern (1L / 1S) having a line width of 60 nm was formed was determined as the optimum exposure amount. The cross-sectional shape of the resist pattern formed with this optimum exposure dose was observed with a scanning electron microscope (S-4800, manufactured by Hitachi High-Technologies). A case where the resist pattern has a rectangular cross-sectional shape was evaluated as “◯”, and a case where the resist pattern was a shape other than a rectangle such as a T-top shape, a top round shape, and a skirt shape was evaluated as “X”.

[Blob defect]
The number of occurrences of blob defects in the resist pattern obtained by developing the resist film on which the liquid immersion upper layer film was formed was measured. A 12-inch silicon wafer subjected to hexamethyldisilazane (HMDS) treatment at 100 ° C. for 60 seconds was prepared using a coating / developing apparatus (Lithius, manufactured by Tokyo Electron). A photoresist composition (α) was spin-coated on this 12-inch silicon wafer, and PB was performed on a hot plate at 90 ° C. for 60 seconds to form a resist film having a thickness of 120 nm. On this resist film, a composition for forming a liquid immersion upper film was spin-coated, and PB was performed at 90 ° C. for 60 seconds to form a liquid immersion upper film having a thickness of 30 nm. Then, it exposed through the frosted glass in which the pattern is not formed. This 12-inch silicon wafer was used for evaluation of blob defects.

  In the evaluation of the blob defect, first, ultrapure water was discharged from a rinse nozzle of a coating / developing apparatus (Lithius, manufactured by Tokyo Electron) for 60 seconds onto a liquid immersion upper layer film of a 12-inch silicon wafer for evaluation, and 4,000 rpm Spin dry by shaking off for 15 seconds. Next, paddle development was performed for 30 seconds using the (Lithius) LD nozzle, and the liquid immersion upper layer film was removed. In this paddle development, a 2.38% TMAH aqueous solution was used as a developer. After development, the number of blob defects was measured using a defect inspection apparatus (KLA2351, manufactured by KLA Tencor). When the number of detected blob defects is 200 or less per wafer, it is evaluated as “◯”, when it exceeds 200 and is 500 or less, “△”, and when it exceeds 500, it is evaluated as “×”. did.

[Bridge defect]
The number of occurrences of bridge defects in the resist pattern obtained by developing the resist film on which the liquid immersion upper layer film was formed was measured. A 12-inch silicon wafer surface was spin-coated with a lower antireflection film (ARC66, manufactured by Nissan Chemical Co., Ltd.) using a coating / developing apparatus (Lithius, manufactured by Tokyo Electron), and then PB was applied to form a coating film having a film thickness of 105 nm. Formed. Next, the photoresist composition (α) was spin-coated using the above (Lithius), PB was applied at 100 ° C. for 60 seconds, and then cooled at 23 ° C. for 30 seconds to form a photoresist film having a thickness of 100 nm. . Thereafter, a composition for forming a liquid immersion upper film was spin-coated on this resist film, and PB was performed at 90 ° C. for 60 seconds to form a liquid immersion upper film having a thickness of 30 nm.

  Next, using an ArF immersion exposure apparatus (S610C, manufactured by NIKON), exposure was performed through a pattern forming mask having a 45 nm line / 90 nm pitch under the optical conditions of NA: 1.30 and Crosspore. Next, PEB is performed on the above-mentioned “Lithius” hot plate at 100 ° C. for 60 seconds and cooled at 23 ° C. for 30 seconds. Paddle development was performed and rinsed with ultrapure water. Thereafter, spin drying was performed by shaking off at 2,000 rpm for 15 seconds to obtain a substrate on which a resist pattern was formed. At this time, the exposure amount at which a resist pattern having a 45 nm line / 90 nm pitch was formed was determined as the optimum exposure amount. In the resist pattern formation at this optimum exposure amount, a case where no bridge defect was observed was evaluated as “◯”, and a case where a bridge defect was observed was evaluated as “x”.

  As is apparent from the results in Table 3, according to the composition for forming an immersion upper layer film of the present invention, an immersion upper layer film exhibiting high water repellency while maintaining performance such as upper layer film removability and peeling resistance. It can be formed and the occurrence of defects such as bridge defects and blob defects in the resist pattern can be suppressed.

  The composition for forming a liquid immersion upper film of the present invention can form a liquid immersion upper film exhibiting high water repellency, and can suppress the occurrence of development defects such as bridge defects and blob defects in resist patterns. . Therefore, the composition for forming a liquid immersion upper layer film can be suitably used in a lithography process that requires further miniaturization.

Claims (12)

(1) forming a resist film on the substrate;
(2) forming a liquid immersion upper film on the resist film using the composition for forming a liquid immersion upper film;
(3) a step of irradiating the resist film on which the liquid immersion upper layer film is laminated with radiation through a photomask to perform liquid immersion exposure; and
(4) Step of developing the immersion-exposed resist film
A liquid immersion upper layer film forming composition used for a resist pattern forming method comprising:
[A] A polymer component containing the polymer (a) having the structural unit (I) represented by the following formula (1), and [B] a composition for forming an immersion upper film containing a solvent.

(In Formula (1), R ¹ is a hydrogen atom or a methyl group. R ² and R ³ are each independently a hydrogen atom, a fluorine atom, a hydroxy group, or an alkyl group having 1 to 6 carbon atoms. Provided that R ² and R ³ are not both hydroxy groups, and R ⁴ and R ⁵ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms and bonded to each other. Then, together with the carbon atom to which they are bonded, a ring structure having 3 to 20 carbon atoms may be formed, part or all of the hydrogen atoms of the ring structure may be substituted. It is an integer of 1 to 4. When n is 2 or more, the plurality of R ² and R ³ may be the same or different. The composition for forming an immersion upper layer film according to claim 1, wherein at least one of R ⁴ and R ⁵ in the formula (1) is a monovalent organic group containing a fluorine atom. The monovalent organic group containing a fluorine atom is represented by -R ^E -R ^f , -R ^E -OR ^f or -R ^E -OCOR ^f , and R ^E is a single bond or a divalent linking group, and R ^f The composition for forming a liquid immersion upper layer film according to claim 2, wherein is a fluorinated alkyl group or a hydroxyfluorinated alkyl group. The composition for forming a liquid immersion upper layer film according to claim 1, wherein the structural unit (I) is represented by the following formula (1-1).

(In the formula (1-1), R ¹ , R ² , R ³ and n have the same meanings as in the above formula (1). R ^A together with the carbon atom constituting the lactone ring has 3 to 20 carbon atoms. The (m + 2) -valent group that forms an alicyclic hydrocarbon group of the above formula, provided that the alicyclic hydrocarbon group includes —CO—, —COO—, —OCO—, —O—, It may contain at least one group selected from the group consisting of —NR—, —CS—, —S—, —SO— and —SO ₂ —, wherein R is a hydrogen atom or a C 1-10 carbon atom. R ^B is a fluorine atom, a hydroxy group, or a monovalent organic group having 1 to 20 carbon atoms, m is an integer of 1 to 6. When m is 2 or more, the plurality of R ^B, may be the same or different. However, at least one of R ^B is an organic group containing a fluorine atom or a fluorine atom A.) R ^B in the above formula (1-1) is represented by —R ^E —R ^f , —R ^E —OR ^f or —R ^E —OCOR ^f , R ^E is a single bond or a divalent linking group, and R ^f The composition for forming a liquid immersion upper layer film according to claim 4, wherein is a fluorinated alkyl group or a hydroxyfluorinated alkyl group. The composition for forming a liquid immersion upper layer film according to claim 1, wherein the structural unit (I) is represented by the following formula (1-2).

(In the formula (1-2), R ¹ , R ² , R ³ and n have the same meaning as in the above formula (1). R ^C has 3 to 20 carbon atoms together with the carbon atoms constituting the lactone ring. A (p + 2) -valent group which forms an alicyclic hydrocarbon group of the above-mentioned alicyclic hydrocarbon group, wherein -CO-, -COO-, -OCO-, -O-, It may contain at least one group selected from the group consisting of —NR—, —CS—, —S—, —SO— and —SO ₂ —, wherein R is a hydrogen atom or a C 1-10 carbon atom. ^RD is a hydroxy group or a monovalent organic group having 1 to 20 carbon atoms, p is an integer of 0 to 6. When p is 2 or more, a plurality of R ^D may be the same or different, provided that R ^D does not contain a fluorine atom. [A] The polymer component further comprises a structural unit (II) represented by the following formula (2) in the same or different polymer as the polymer (a). Item 4. A composition for forming a liquid immersion upper film according to Item.

(In the formula (2), R ⁶ is a hydrogen atom, a methyl group, a fluorine atom or a trifluoromethyl group. R ⁷ is a C 1-6 linear or branched alkyl group having a fluorine atom. Or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms having a fluorine atom, provided that a part or all of the hydrogen atoms of the alkyl group and alicyclic hydrocarbon group may be substituted. Good.)   [A] The polymer component is at least selected from the group consisting of a structural unit containing a fluorinated sulfonamide group and a structural unit containing an α-trifluoromethyl alcohol group in the same or different polymer as the polymer (a). The composition for forming a liquid immersion upper layer film according to any one of claims 1 to 7, further comprising one type of structural unit (III).   [A] The liquid according to any one of claims 1 to 8, wherein the polymer component further has a structural unit (IV) containing a sulfo group in the same or different polymer as the polymer (a). A composition for forming a submerged layer film. [A] The polymer component is at least selected from the group consisting of a structural unit containing a carboxy group and a structural unit containing a group represented by the following formula (v) in the same or different polymer as the polymer (a). The composition for forming a liquid immersion upper layer film according to any one of claims 1 to 9, further comprising one type of structural unit (V).

(In the formula (v), R ⁸ 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. The above alkyl group A part or all of hydrogen atoms of the alicyclic hydrocarbon group, alkoxy group, acyl group, aralkyl group and aryl group may be substituted, and R ⁹ is —C (═O) —R ¹⁰ , —S (═O) ₂ —R ¹¹ , —R ¹² —CN or —R ¹³ —NO ₂ , wherein R ¹⁰ and R ¹¹ are each independently a hydrogen atom, an alkyl group, a fluorinated alkyl group, 1 A valent alicyclic hydrocarbon group, an alkoxy group, a cyano group, a cyanomethyl group, an aralkyl group or an aryl group, provided that R ¹⁰ or R ¹¹ and R ⁸ may be bonded to each other to form a ring structure. good ^{.R 12} and ^{R 13} Each, independently, a single bond, a methylene group or an alkylene group having 2 to 5 carbon atoms.)   [B] The composition for forming a liquid immersion upper layer film according to any one of claims 1 to 10, wherein the solvent contains an ether solvent. (1) forming a resist film on the substrate;
(2) A step of forming a liquid immersion upper film on the resist film using the composition for liquid immersion upper film formation according to any one of claims 1 to 11,
(3) a step of irradiating the resist film on which the liquid immersion upper layer film is laminated with a radiation through a photomask to perform liquid immersion exposure; and (4) a resist having a process of developing the liquid immersion exposed resist film. Pattern forming method.