JP6515658B2 - Method for forming resist pattern and radiation sensitive resin composition - Google Patents

Description

  The present invention relates to a method of forming a resist pattern and a radiation sensitive resin composition.

  With the miniaturization of various electronic device structures such as semiconductor devices and liquid crystal devices, miniaturization of the resist pattern in the lithography process is required, and a fine resist with a line width of about 90 nm is required using ArF excimer laser which is radiation of short wavelength. It is considered to form a pattern. Various resist compositions that can respond to such short wavelength radiation are being studied, and as these resist compositions, an acid is generated in the exposed area by irradiation (exposure) of radiation, and the acid action of the acid causes exposure A radiation sensitive resin composition is known which causes a difference in dissolution rate of a part and a non-exposed part in a developing solution to form a resist pattern on a substrate.

  On the other hand, as a technology for enhancing the resolution using such characteristics of the radiation sensitive resin composition and without increasing the number of steps using an existing apparatus, a technology using an organic solvent having a polarity lower than that of an alkaline aqueous solution as a developer is known. (See Japanese Patent Application Laid-Open No. 2000-199953). Thus, when an organic solvent is used, the optical contrast can be increased, and as a result, a fine pattern can be formed.

  In the resist pattern forming method using such an organic solvent as a developer, when a conventional radiation sensitive resin composition is used, the shrinkage of the resist film tends to be manifested due to the use of the organic solvent in the developer. is there. That is, although the resist film in the exposed area tends to shrink by post-exposure baking (PEB) performed after exposing the resist film, in the development with an alkaline aqueous solution, the shrunk exposed area is removed. It is difficult for contraction to manifest. On the other hand, when developing with an organic solvent after PEB, since the resist pattern of the shrunk exposed part remains, the shrinkage of the resist film tends to be apparent.

  In addition, as described above, when shrinkage of the resist film becomes apparent, it is considered that LWR (Line Width Roughness), resolution, rectangularity of sectional shape, depth of focus (DOF), etc. It's getting harder to improve.

JP 2000-199953 A

  The present invention has been made based on the above circumstances, and an object thereof is to suppress the shrinkage of a resist film at the time of PEB while enhancing optical contrast by using a developer containing an organic solvent. It is an object of the present invention to provide a method for forming a resist pattern and a radiation sensitive resin composition which can improve LWR, resolution, rectangularity in cross section and depth of focus.

（式（１）中、Ｒ^１は、１価又は２価の有機基である。＊は、上記アダマンタン環に結合する部位を示す。） The invention made in order to solve the above problems comprises the steps of forming a resist film with a radiation sensitive resin composition, exposing the resist film, and developing the exposed resist film with a developer containing an organic solvent. And the radiation sensitive resin composition contains a polymer, a radiation sensitive acid generator, and a solvent, the solubility of which in the developer decreases due to the action of an acid. The polymer is characterized in that it has a structural unit containing a first group, and the first group contains an adamantane ring substituted by a substituent represented by the following formula (1).

(In formula (1), R ¹ is a monovalent or divalent organic group. * Represents a site to be bonded to the adamantane ring.)

（式（２−１）中、Ｒ^２は、炭素数１〜２０の１価の有機基である。Ｒ^３は、シアノメチル基、ヒドロキシエチル基、炭素数３〜２０の１価の鎖状有機基、炭素数３〜２０の１価の脂環式炭化水素基、シアノ基若しくはヒドロキシ基で置換された炭素数３〜２０の１価の脂環式炭化水素基、炭素数３〜２０の１価の脂肪族複素環基又は炭素数３〜２０の１価の脂肪族複素環基で置換された炭素数１〜２０の１価の炭化水素基である。ｐ１は、１〜１４の整数である。ｐ１が２以上の場合、複数のＲ^３は同一でも異なっていてもよく、複数の−ＯＲ^３のうちの２つ以上が互いに合わせられこれらが結合する炭素原子又は炭素鎖と共に環員数３〜２０の環構造を形成していてもよい。Ｒ^４は、−ＯＲ^３以外の炭素数１〜２０の１価の有機基又は＝Ｏである。ｐ２は、０〜１３の整数である。ｐ２が２以上の場合、複数のＲ^４は同一でも異なっていてもよく、複数のＲ^４のうちの２つ以上が互いに合わせられこれらが結合する炭素原子又は炭素鎖と共に環員数３〜２０の環構造を形成していてもよい。ただし、ｐ１＋ｐ２は１４以下である。＊は、上記構造単位の第１基以外の部分に結合する部位を示す。）

（式（２−２）中、Ｒ^５及びＲ^６は、それぞれ独立して炭素数１〜２０の１価の有機基であるか、又はこれらの基が互いに合わせられこれらが結合する炭素原子と共に構成される環員数３〜２０の環構造の一部を表す。Ｒ^７及びＲ^８は、それぞれ独立して水素原子又は炭素数１〜２０の１価の有機基である。ｑ１は、０〜５の整数である。ｑ１が２以上の場合、複数のＲ^７は同一でも異なっていてもよく、複数のＲ^８は同一でも異なっていてもよい。１又は複数のＲ^７及び１又は複数のＲ^８のうちの２つ以上は、これらの基が互いに合わせられこれらが結合する炭素原子又は炭素鎖と共に環員数３〜２０の環構造を形成していてもよい。Ｒ^９は、シアノメチル基、ヒドロキシエチル基、炭素数３〜２０の１価の鎖状有機基、炭素数３〜２０の１価の脂環式炭化水素基、シアノ基若しくはヒドロキシ基で置換された炭素数３〜２０の１価の脂環式炭化水素基、炭素数３〜２０の１価の脂肪族複素環基又は炭素数３〜２０の１価の脂肪族複素環基で置換された炭素数１〜２０の１価の炭化水素基である。ｑ２は、１〜１５の整数である。ｑ２が２以上の場合、複数のＲ^９は同一でも異なっていてもよく、複数の−ＯＲ^９のうちの２つ以上が互いに合わせられこれらが結合する炭素原子又は炭素鎖と共に環員数３〜２０の環構造を形成していてもよい。Ｒ^１０は、−ＯＲ^９以外の炭素数１〜２０の１価の有機基又は＝Ｏである。ｑ３は、０〜１４の整数である。ｑ３が２以上の場合、複数のＲ^１０は同一でも異なっていてもよく、複数のＲ^１０のうちの２つ以上が互いに合わせられこれらが結合する炭素原子又は炭素鎖と共に環員数３〜２０の環構造を形成していてもよい。ただし、ｑ２＋ｑ３は１５以下である。＊は、上記構造単位の第１基以外の部分に結合する部位を示す。）

（式（３）中、Ｒ^１１及びＲ^１２は、それぞれ独立して炭素数１〜２０の１価の有機基である。Ｒ^１３は、炭素数１〜２０の１価の有機基又は＝Ｏである。ｒは、０〜１５の整数である。ｒが２以上の場合、複数のＲ^１３は同一でも異なっていてもよく、複数のＲ^１３のうちの２つ以上が互いに合わせられこれらが結合する炭素原子又は炭素鎖と共に環員数３〜２０の環構造を形成していてもよい。Ｌ^１は、単結合又は炭素数１〜２０の２価の有機基である。Ｒ^１１、Ｒ^１２及びＬ^１のうちの２つ以上が互いに合わせられこれらが結合する炭素原子と共に環員数３〜２０の環構造を形成していてもよい。＊は、上記構造単位の第１基以外の部分に結合する部位を示す。） Another invention made in order to solve the above-mentioned subject is a radiation sensitive resin containing a polymer, a radiation sensitive acid generator, and a solvent whose solubility to a developing solution containing an organic solvent falls by the action of an acid. A composition, wherein the polymer has a structural unit containing a first acid dissociable group represented by the following formula (2-1), the following formula (2-2) or the following formula (3) It features.

(In formula (2-1), R ² is a monovalent organic group having 1 to 20 carbon atoms. R ³ is a cyanomethyl group, a hydroxyethyl group, a monovalent chain organic having 3 to 20 carbon atoms Group, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms substituted with a cyano group or a hydroxy group, 1 having 3 to 20 carbon atoms A monovalent hydrocarbon group of 1 to 20 carbon atoms substituted with a divalent aliphatic heterocyclic group or a monovalent aliphatic heterocyclic group of 3 to 20 carbon atoms, p 1 is an integer of 1 to 14 When p1 is 2 or more, a plurality of R ^{3 s} may be the same or different, and two or more of a plurality of —OR ³ are combined with each other and the carbon atom or carbon chain to which they are bonded has 3 ring members optionally form a ring structure to 20 .R ⁴ is a monovalent organic group or the carbon atoms other than -OR ³ 1 to 20 = Is O .P2 the case of .P2 2 or more is an integer of 0 to 13, a plurality of R ⁴ may be the same or different, two or more of the plurality of R ⁴ are combined with each other They may form a ring structure having 3 to 20 ring members together with a carbon atom or a carbon chain to which they are attached, provided that p1 + p2 is 14 or less. * Is a bond to a moiety other than the first group of the structural unit Indicate the location of

(In formula (2-2), R ⁵ and R ⁶ are each independently a monovalent organic group having 1 to 20 carbon atoms, or these groups are combined with each other and together with the carbon atom to which they are bonded] R ⁷ and R ⁸ each independently represent a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, and q 1 is a group of 0 to 20. When q1 is 2 or more, a plurality of R ⁷ may be the same or different, and a plurality of R ⁸ may be the same or different 1 or more R ⁷ and one or more two or more of R ⁸ is optionally .R ⁹ to form a ring structure of ring members 3 to 20, together with keyed these groups with each other carbon atom or carbon chain they are attached, a cyanomethyl group, Hydroxyethyl group, monovalent linear organic group having 3 to 20 carbon atoms, 3 to 3 carbon atoms A monovalent alicyclic hydrocarbon group of 0, a monovalent alicyclic hydrocarbon group of 3 to 20 carbon atoms substituted with a cyano group or a hydroxy group, a monovalent aliphatic heterocyclic ring of 3 to 20 carbon atoms It is a C1-C20 monovalent hydrocarbon group substituted by the group or C3-C20 monovalent aliphatic heterocyclic group q2 is an integer of 1-15 q2 is 2 or more In the case of a plurality of R ⁹ may be the same or different, and two or more of a plurality of -OR ⁹ are combined with each other and together with the carbon atom or carbon chain to which they are attached R ¹⁰ is a monovalent organic group having 1 to 20 carbon atoms other than —OR ⁹ or OO, q 3 is an integer of 0 to 14. q 3 is 2 or more , the plurality of R ¹⁰ may be the same or different, combined two or more of the plurality of R ¹⁰ are mutually Or a carbon atom to which they are attached or a carbon chain may form a ring structure having 3 to 20 ring members, provided that q 2 + q 3 is 15 or less. * Is a moiety other than the first group of the structural unit Indicates the binding site.)

(In formula (3), R ¹¹ and R ¹² are each independently a monovalent organic group having 1 to 20 carbon atoms. R ¹³ is a monovalent organic group having 1 to 20 carbon atoms or OO R is an integer of 0 to 15. When r is 2 or more, a plurality of R ¹³ may be the same or different, and 2 or more of a plurality of R ¹³ may be combined with one another. It may form a ring structure having 3 to 20 ring members together with the carbon atom or carbon chain to be bound.L ¹ is a single bond or a divalent organic group having 1 to 20 carbon atoms, R ¹¹ and R ¹² And two or more of L ¹ may be combined with each other to form a ring structure of 3 to 20 ring members with a carbon atom to which they are bonded. * Represents a moiety other than the first group of the above structural units Indicates the binding site.)

（式（４−１）中、Ｒ^１４及びＲ^１５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１〜２０の１価の有機基である。ｓ１は、０〜５の整数である。ｓ１が２以上の場合、複数のＲ^１４は同一でも異なっていてもよく、複数のＲ^１５は同一でも異なっていてもよい。１又は複数のＲ^１４及び１又は複数のＲ^１５のうちの２つ以上は、これらの基が互いに合わせられこれらが結合する炭素原子又は炭素鎖と共に環員数３〜２０の環構造を形成していてもよい。Ｒ^１６は、炭素数１〜２０の１価の有機基である。ｓ２は、１〜１４の整数である。ｓ２が２以上の場合、複数のＲ^１６は同一でも異なっていてもよく、複数の−ＯＲ^１６のうちの２つ以上が互いに合わせられこれらが結合する炭素原子又は炭素鎖と共に環員数３〜２０の環構造を形成していてもよい。Ｒ^１７は、−ＯＲ^１６以外の炭素数１〜２０の１価の有機基又は＝Ｏである。ｓ３は、０〜１３の整数である。ｓ３が２以上の場合、複数のＲ^１７は同一でも異なっていてもよく、複数のＲ^１７のうちの２つ以上が互いに合わせられこれらが結合する炭素原子又は炭素鎖と共に環員数３〜２０の環構造を形成していてもよい。ただし、ｓ２＋ｓ３は１４以下である。＊１は、上記構造単位の第１基以外の部分に結合する部位を示す。＊２は、上記構造単位に隣接する構造単位に結合する部位を示す。）

（式（４−２）中、Ｒ^１８及びＲ^１９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１〜２０の１価の有機基である。ｔ１は、０〜５の整数である。ｔ１が２以上の場合、複数のＲ^１８は同一でも異なっていてもよく、複数のＲ^１９は同一でも異なっていてもよい。１又は複数のＲ^１８及び１又は複数のＲ^１９のうちの２つ以上は、これらの基が互いに合わせられこれらが結合する炭素原子又は炭素鎖と共に環員数３〜２０の環構造を形成していてもよい。Ｒ^２０は、炭素数１〜２０の１価の有機基である。Ｌ^２は、単結合又は炭素数１〜２０の２価の有機基である。Ｒ^２０及びＬ^２が互いに合わせられこれらが結合する炭素原子と共に環員数３〜２０の環構造を形成していてもよい。Ｒ^２１は、炭素数１〜２０の１価の有機基である。ｔ２は、１〜１４の整数である。ｔ２が２以上の場合、複数のＲ^２１は同一でも異なっていてもよく、複数の−ＯＲ^２１のうちの２つ以上が互いに合わせられこれらが結合する炭素原子又は炭素鎖と共に環員数３〜２０の環構造を形成していてもよい。Ｒ^２２は、−ＯＲ^２１以外の炭素数１〜２０の１価の有機基又は＝Ｏである。ｔ３は、０〜１３の整数である。ｔ３が２以上の場合、複数のＲ^２２は同一でも異なっていてもよく、複数のＲ^２２のうちの２つ以上が互いに合わせられこれらが結合する炭素原子又は炭素鎖と共に環員数３〜２０の環構造を形成していてもよい。ただし、ｔ２＋ｔ３は１４以下である。＊１は、上記構造単位の第１基以外の部分に結合する部位を示す。＊２は、上記構造単位に隣接する構造単位に結合する部位を示す。） Still another invention made to solve the above-mentioned problems is a radiation-sensitive polymer containing a polymer, a radiation-sensitive acid generator, and a solvent in which the solubility in a developer containing an organic solvent is reduced by the action of an acid. It is a resin composition, and the above-mentioned polymer is characterized by having a structural unit containing the 1st group denoted by a following formula (4-1) or a following formula (4-2).

(In formula (4-1), R ¹⁴ and R ¹⁵ each independently represent a hydrogen atom, a fluorine atom, a hydroxy group or a monovalent organic group having 1 to 20 carbon atoms. S1 is 0 to 5) When s1 is 2 or more, a plurality of R ¹⁴ may be the same or different, and a plurality of R ¹⁵ may be the same or different 1 or more R ¹⁴ and one or more R ¹⁵ two or more of, good .R ¹⁶ to form a ring structure of ring members 3 to 20, together with keyed these groups together carbon atoms or a carbon chain which they are attached, having from 1 to 20 carbon atoms S2 is an integer of 1 to 14. When s2 is 2 or more, a plurality of R ¹⁶ may be the same or different, and two of a plurality of -OR ¹⁶ The above are combined together with the carbon atom or carbon chain to which they are attached Good ^.R 17 also form a ring structure membered 3-20 is a monovalent organic group or = O at carbon atoms other than ^{-OR 16 1~20 .s3} is an integer of 0 to 13 If there .s3 is 2 or more, plural R ¹⁷ may be the same or different, ring members 3 together with the carbon atom or carbon chain two or more of the plurality of R ¹⁷ are combined they are bound to each other It may form a ring structure of 20. However, s 2 + s 3 is 14 or less * 1 represents a site to be bonded to a moiety other than the first group of the structural unit * 2 represents the structural unit Indicates a site binding to an adjacent structural unit.)

(In formula (4-2), R ¹⁸ and R ¹⁹ each independently represent a hydrogen atom, a fluorine atom, a hydroxy group or a monovalent organic group having 1 to 20 carbon atoms. T1 is 0 to 5) When t1 is 2 or more, a plurality of R ¹⁸ may be the same or different, and a plurality of R ¹⁹ may be the same or different 1 or more R ¹⁸ and one or more R ¹⁹ two or more of, good .R ²⁰ to form a ring structure of ring members 3 to 20, together with keyed these groups together carbon atoms or a carbon chain which they are attached, having from 1 to 20 carbon atoms L ² is a single bond or a divalent organic group having 1 to ²⁰ carbon atoms, and R ²⁰ and L ² are combined with each other, and together with the carbon atom to which they are bonded, 3 to 3 ring members. optionally form a ring structure of 20 ^{.R 21} is 1 to carbon atoms 0 is a monovalent organic group .t2 the case of .t2 2 or more is an integer of 1 to 14, a plurality of ^{R 21} may be the same or different, two of the plurality of ^{-OR 21} One or more may be combined with each other to form a ring structure having 3 to 20 ring members with a carbon atom or a carbon chain to which they are attached. R ²² is a monovalent having 1 to 20 carbon atoms other than -OR ²¹ . organic group or a = a O .T3 the case of .T3 2 or more is an integer of 0 to 13, a plurality of ^{R 22} may be the same or different, two or more of the plurality of ^{R 22} is They may be combined with each other to form a ring structure having 3 to 20 ring members together with carbon atoms or carbon chains to which they are bonded, provided that t2 + t3 is 14 or less. * 1 is other than the first group of the structural units Indicates a site binding to the moiety of * .2 is adjacent to the above structural unit Indicates the site bound to the adjacent structural unit.)

  Here, "organic group" refers to a group containing at least one carbon atom. The "chain organic group" refers to an organic group which does not contain a cyclic structure and is constituted only by a chain structure, and includes both a linear organic group and a branched organic group. The "hydrocarbon group" includes a chain hydrocarbon group, an alicyclic hydrocarbon group and an aromatic hydrocarbon group. The "hydrocarbon group" may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. "Chain chain hydrocarbon group" refers to a hydrocarbon group that does not contain a cyclic structure and is composed only of a chain structure, and includes both a linear hydrocarbon group and a branched hydrocarbon group. "Alicyclic hydrocarbon group" refers to a hydrocarbon group containing only an alicyclic structure as a cyclic structure and not containing an aromatic ring structure, and a monocyclic alicyclic hydrocarbon group and polycyclic alicyclic carbonization Includes both hydrogen groups. However, it does not need to be comprised only with an alicyclic structure, and the chain-like structure may be included in the one part. The "aromatic hydrocarbon group" refers to a hydrocarbon group containing an aromatic ring structure as a cyclic structure, and includes both a monocyclic aromatic hydrocarbon group and a polycyclic aromatic hydrocarbon group. However, it is not necessary to be composed of only an aromatic ring structure, and a chain structure or an alicyclic structure may be included in part thereof. The "heterocyclic group" refers to a group containing a cyclic structure composed of carbon atoms and atoms other than carbon atoms. The "aliphatic heterocyclic group" refers to a heterocyclic group not containing an aromatic ring structure, and includes both a monocyclic aliphatic heterocyclic group and a polycyclic aliphatic heterocyclic group. However, it is not necessary to be composed only of a heterocycle, and at least one of a hydrocarbon group and = O may be bonded to the heterocycle. The “number of ring members” refers to the number of atoms constituting a cyclic structure, and in the case of a polycyclic ring, refers to the number of atoms constituting this polycyclic ring. The "acid dissociable group" is a group that substitutes a hydrogen atom of a polar group such as a hydroxy group or a carboxy group, and is a group that can be dissociated by the action of an acid.

  According to the resist pattern forming method and the radiation sensitive resin composition of the present invention, it is possible to suppress the shrinkage of the resist film at the time of PEB while enhancing the optical contrast by using the developing solution containing the organic solvent, and LWR , Resolution, rectangularity in cross-sectional shape, and depth of focus can be improved.

<Method for forming resist pattern>
The said resist pattern formation method is a process (henceforth a "resist film formation process") of forming a resist film with a radiation sensitive resin composition, a process (henceforth, an exposure process) of exposing the said resist film. And a step of developing the exposed resist film with a developer containing an organic solvent (hereinafter, also referred to as “developing step”), wherein the radiation sensitive resin composition is And a polymer, a radiation-sensitive acid generator and a solvent whose solubility in the developer decreases due to the action of an acid, the polymer having a structural unit containing a first group, and the first group Are characterized in that they contain an adamantane ring substituted by a substituent represented by the formula (1) described later. Hereinafter, the said resist pattern formation method is demonstrated.

[Resist film formation process]
In this step, a resist film is formed of a radiation sensitive resin composition described later. Examples of the substrate on which the resist film is formed include a silicon wafer, a wafer coated with aluminum or the like. Examples of the coating method include spin coating, cast coating, and roll coating. The lower limit of the film thickness of the resist film to be formed is preferably 10 nm. The upper limit of the film thickness is preferably 1,000 nm, and more preferably 500 nm.

  After applying a radiation sensitive resin composition described later, heat treatment (hereinafter, also referred to as “pre-baking (PB)”) may be performed, for example, at a temperature of 70 ° C. or more and 160 ° C. or less.

  In order to reduce the influence of basic impurities and the like contained in the environmental atmosphere, for example, a protective film described in JP-A-5-188598 can be provided on the resist film.

[Exposure process]
At this process, the resist film formed at the said resist film formation process is exposed. This exposure is performed, for example, through a predetermined mask pattern.

  As radiation used for the above-mentioned exposure, electromagnetic waves such as visible light, ultraviolet light, far ultraviolet light, extreme ultraviolet light (wavelength 13.5 nm, EUV), X-rays, etc., charged particles such as electron beams and α-rays are appropriately selected. However, far ultraviolet rays represented by ArF excimer laser light (wavelength 193 nm) and KrF excimer laser light (wavelength 248 nm) are preferable, and in particular, KrF excimer laser light is preferable. Exposure conditions, such as an exposure amount, are suitably selected according to the compounding composition of a radiation sensitive resin composition, the kind of additive, etc.

  In order to stably form a fine resist pattern with high accuracy, it is preferable to perform post-exposure bake (PEB) after exposure. By performing PEB, the dissociation reaction of the acid dissociable group in the radiation sensitive resin composition can smoothly proceed. As a minimum of heating temperature of PEB from a viewpoint of making a dissociation reaction of an acid dissociatable group advance smoothly, 30 ° C is preferred and 50 ° C is more preferred. From the same viewpoint, the upper limit of the temperature is preferably 200 ° C., and more preferably 170 ° C.

[Development process]
At this process, the resist film exposed at the said exposure process is developed using the developing solution containing the organic solvent, and a resist pattern is formed. In addition, the developing solution which can be used for the said resist pattern formation method is a developing solution which melt | dissolves or removes a low exposure part and a non-exposure part selectively. From the viewpoint of improving the contrast of the resist pattern, the organic solvent contained in such a developing solution is preferably an alcohol solvent, an ether solvent, a ketone solvent, an amide solvent, an ester solvent, a hydrocarbon solvent, or two of them. Combinations of species or more are preferred.

Examples of alcohol solvents include methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, sec-butanol, tert-butanol, n-pentanol, i-pentanol, 2-methylbutanol, sec-pentanol, tert-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, 3-heptanol, n-octanol, 2-ethylhexanol Sec-octanol, n-nonyl alcohol, 2,6-dimethyl-4-heptanol, n-decanol, sec-undecyl alcohol, trimethyl nonyl alcohol, sec-tetradecyl alcohol, sec-heptadec Monoalcohol solvents such as alcohol, furfuryl alcohol, phenol, cyclohexanol, methylcyclohexanol, 3,3,5-trimethylcyclohexanol, benzyl alcohol and diacetone alcohol;
Ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4-heptanediol, 2 -Polyhydric alcohol solvents such as ethyl 1,3-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol and the like;
Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, ethylene glycol mono-2-ethyl butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl Ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol Monomethyl ether, dipropylene glycol monoethyl ether, and polyhydric alcohol partial ether solvents such as dipropylene glycol monopropyl ether.

  Examples of the ether solvents include diethyl ether, dipropyl ether, dibutyl ether, diphenyl ether, methoxybenzene and the like.

  Examples of ketone solvents include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, methyl-n-amyl ketone, diethyl ketone, methyl-i-butyl ketone, methyl-n-pentyl ketone, ethyl-n- Butyl ketone, methyl n-hexyl ketone, di-i-butyl ketone, trimethylnonanone, cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, methylcyclohexanone, 2,4-pentanedione, acetonylacetone, acetophenone, etc. It can be mentioned.

  Examples of amide solvents include N, N'-dimethylimidazolidinone, N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, N-methyl propionamide, N-methyl pyrrolidone etc. are mentioned.

  As ester solvents, for example, diethyl carbonate, propylene carbonate, amyl acetate, methyl acetate, ethyl acetate, γ-butyrolactone, γ-valerolactone, n-propyl acetate, i-propyl acetate, n-butyl acetate, i-butyl acetate , Sec-butyl acetate, n-pentyl acetate, sec-pentyl acetate, 3-methoxybutyl acetate, methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methyl acetate cyclohexyl, n-nonyl acetate Methyl acetoacetate, ethyl acetoacetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene acetate Glycol mono-n-butyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, diacetic acid Glycol, methoxytriglycol acetate, ethyl propionate, n-butyl propionate, i-amyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl lactate, ethyl lactate, n-butyl lactate, n-amyl lactate , Diethyl malonate, dimethyl phthalate, diethyl phthalate and the like.

Examples of hydrocarbon solvents include n-pentane, i-pentane, n-hexane, i-hexane, n-heptane, i-heptane, 2,2,4-trimethylpentane, n-octane, i-octane and cyclohexane , Aliphatic hydrocarbon solvents such as methylcyclohexane;
Aromatics such as benzene, toluene, xylene, mesitylene, ethylbenzene, trimethylbenzene, methylethylbenzene, n-propylbenzene, i-propylbenzene, diethylbenzene, i-butylbenzene, triethylbenzene, di-i-propylbenzene, n-amylnaphthalene Group hydrocarbon solvents and the like.

  Among these organic solvents, n-butyl acetate, i-propyl acetate, amyl acetate, methyl ethyl ketone, methyl n-butyl ketone and methyl n-amyl ketone are preferable from the viewpoint of improving the contrast of the resist pattern. These organic solvents may be used alone or in combination of two or more.

  From the viewpoint of improving the contrast of the resist pattern, the lower limit of the content of the organic solvent in the developer is preferably 70% by mass, more preferably 80% by mass, and still more preferably 90% by mass. From the same viewpoint, 100% by mass is preferable as the upper limit of the content. In addition, as a component which can be mix | blended except the organic solvent in a developing solution, water, a silicone oil, surfactant etc. are mentioned, for example.

  As the above-mentioned surfactant, for example, an ionic or nonionic fluorine-based surfactant and / or a silicon-based surfactant can be used.

  As a developing method, for example, a method of immersing a substrate in a bath filled with a developer for a certain time (dip method), a method of raising a developer on the substrate surface by surface tension and developing by standing for a certain time (paddle method A method of spraying a developer onto the substrate surface (spray method), a method of continuously coating a developer onto a substrate rotating at a constant speed while scanning a developer coating nozzle at a constant speed (dynamic dispense method) Etc.

  In the said resist pattern formation method, it is preferable to wash | clean a resist film by rinse agent after a development process. As the rinse solution in the rinse step, it is preferable to use an organic solvent in order to efficiently wash the generated scum. As the rinse solution, hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents and the like are preferable. Among these, alcohol solvents and ester solvents are preferable, and a C 6-8 monohydric alcohol solvent is more preferable. Examples of the C 6-8 monohydric alcohol include linear, branched or cyclic monohydric alcohols, such as 1-hexanol, 1-heptanol, 1-octanol, 4-methyl-2-pentanol 2-hexanol, 2-heptanol, 2-octanol, 3-hexanol, 3-heptanol, 3-octanol, 4-octanol, benzyl alcohol and the like. Among these, 1-hexanol, 2-hexanol, 2-heptanol and 4-methyl-2-pentanol are preferable.

  Each component of the rinse solution may be used alone or in combination of two or more. The water content in the rinse solution is preferably 10% by mass or less, more preferably 5% by mass or less, and still more preferably 3% by mass or less. By setting the water content to 10% by mass or less, good development characteristics can be obtained. A surfactant can be added to the rinse solution.

  As a method of cleaning treatment, for example, a method of continuously applying a rinse liquid on a substrate rotating at a constant speed (rotation coating method), a method of immersing a substrate in a bath filled with a rinse liquid for a predetermined time (dip method) And a method (spray method) of spraying a rinse liquid on the substrate surface.

Radiation-sensitive resin composition
Next, a radiation sensitive resin composition (hereinafter, also referred to as “a radiation sensitive resin composition (I)”) used in the above-described resist pattern forming method will be described. The radiation sensitive resin composition (I) is a polymer (hereinafter, also referred to as "[A] polymer") whose solubility in the above developer decreases due to the action of an acid, a radiation sensitive acid generator (hereinafter referred to as And [(B) acid generator] and a solvent (hereinafter, also referred to as "(C) solvent"). The radiation sensitive resin composition (I) may contain a [D] acid diffusion controller, and may contain other components as long as the effects of the present invention are not impaired. .

  [A] The polymer has a structural unit (hereinafter also referred to as "structural unit (I)") containing a first group (hereinafter also referred to as "group (I)"), and the group (I) is And an adamantane ring substituted by a substituent represented by the following formula (1).

In the above formula (1), R ¹ is a monovalent or divalent organic group. * Represents a site bound to the above adamantane ring.

As the ^{R 1,} preferably an organic group having 1 to 30 carbon atoms. The substituent may be bonded to either the 1-position carbon atom or the 2-position carbon atom constituting the adamantane ring. In addition, one or more of the substituents may be bonded to the adamantane ring. When two or more of the above substituents are bound to the above adamantane ring, plural R ^{1 s} may be the same or different.

  In the resist pattern formation method, when the radiation sensitive resin composition (I) is used, in the exposed part, the action of the acid generated from the [B] acid generator in the radiation sensitive resin composition (I) A) The polarity of the polymer is increased and the polymer becomes poorly soluble in a developer containing an organic solvent, whereby a negative resist pattern is obtained. In the said resist pattern formation method, in addition to being able to suppress shrinkage | contraction of the resist film at the time of PEB by using radiation sensitive resin composition (I), LWR, resolution, the rectangularity of a cross-sectional shape, and a focus The depth can be improved.

  The reason why the shrinkage of the resist film at the PEB can be suppressed by using the radiation sensitive resin composition (I) is not necessarily clear, but it can be presumed, for example, as follows. Since the radiation sensitive resin composition (I) contains an adamantane ring whose bulkiness is increased by the introduction of a substituent via an oxygen atom, it is presumed that the shrinkage of the resist film at the time of PEB can be suppressed. . Further, even when the group (I) containing an adamantane ring is an acid dissociable group, the separated group (I) becomes difficult to evaporate due to the bulkiness of the adamantane ring, and the group (I) becomes in the resist film. Since it is easy to stay, it is thought that the same effect as the above can be obtained. Further, with regard to the reasons for the improvement of LWR, resolution, rectangularity of cross-sectional shape and depth of focus (hereinafter collectively referred to as “LWR etc.”), in addition to suppressing the above-mentioned film contraction, Since the oxygen atom bonded to the ring interacts appropriately with the acid generated from the [B] acid generator, the diffusion length of the acid is appropriately shortened, and as a result, it is presumed that LWR and the like are improved. Furthermore, in the case where the acid generator [B] acid generator is described later, since the oxygen atom bonded to the adamantane ring interacts appropriately with the acid generator, the distribution of the acid generator in the resist film is As a result, it is presumed that LWR and the like will be further improved. Hereinafter, each component of radiation sensitive resin composition (I) is demonstrated.

<[A] polymer>
[A] The polymer is a polymer in which the solubility in the developer decreases by the action of an acid, and has a structural unit (I) containing a group (I). [A] The polymer preferably has a structural unit containing an acid dissociable group. The structural unit containing the acid dissociable group may be the structural unit (I) or another structural unit in the polymer [A]. Examples of other structural units containing an acid dissociable group include structural units (II) described later. When the structural unit (I) contains an acid dissociable group, the group (I) may be an acid dissociable group, or a part of the group (I) may be an acid dissociable group. [A] The polymer may have the above-mentioned structural unit (II) and a structural unit (III) described later, in addition to the structural unit (I), and structural units (I), (II) and (A) In addition to III), other structural units may be included. [A] The polymer may have one or more of each structural unit. Each structural unit will be described below.

[Structural unit (I)]
Structural unit (I) contains group (I). From the viewpoint of further suppressing the shrinkage of the resist film and the viewpoint of further improving LWR and the like, it is preferable that the group (I) contains a tertiary carbon atom bonded to one oxygen atom. The group (I) may or may not be an acid dissociable group, but when the group (I) is an acid dissociable group, a group dissociated by the action of an acid ( Since the polar part in a resist film increases moderately by I's staying without transpiration | evaporation, the diffusion length of the acid generated from [B] acid generator can be shortened moderately. Thereby, LWR etc. can be improved more. In addition, when the group (I) is an acid dissociable group, the contraction of the resist film can be further suppressed because the group (I) dissociated by the action of the acid remains without transpiration.

  When the group (I) is an acid dissociable group, an acid dissociable group represented by the following formula (2-1) is preferable from the viewpoint of further suppressing the shrinkage of the resist film and the viewpoint of further improving LWR and the like. .

In the above formula (2-1), ^{R 2} is a monovalent organic group having 1 to 20 carbon atoms. R ³ is substituted with cyanomethyl group, hydroxyethyl group, monovalent chain organic group having 3 to 20 carbon atoms, monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, cyano group or hydroxy group Carbon substituted with a C3-C20 monovalent alicyclic hydrocarbon group, a C3-C20 monovalent aliphatic heterocyclic group, or a C3-C20 monovalent aliphatic heterocyclic group It is a number 1-20 monovalent hydrocarbon group. p1 is an integer of 1-14. When p1 is 2 or more, a plurality of R ^{3 s} may be the same or different, and two or more of a plurality of —OR ³ are combined with each other and the carbon atom or carbon chain to which they are bonded together has 3 to 20 ring members May form a ring structure of R ⁴ is a C 1-20 monovalent organic group other than —OR ³ or OO. p2 is an integer of 0 to 13. If p2 is 2 or more, plural R ⁴ may be the same or different, ring members 3 to 20 together with the carbon atom or carbon chain two or more of the plurality of R ⁴ are combined they are bound to each other It may form a ring structure. However, p1 + p2 is 14 or less. * Shows the site | part couple | bonded with parts other than group (I) of structural unit (I).

As a C1-C20 monovalent organic group represented by said R < ² >, a C1-C20 monovalent hydrocarbon group, the terminal of the carbon-carbon of this hydrocarbon group, or the bond side is mentioned, for example And groups having a hetero atom-containing group, and groups in which some or all of the hydrogen atoms of these groups are substituted with a substituent, and the like.

  As said C1-C20 monovalent hydrocarbon group, a monovalent | monohydric chain | strand-shaped hydrocarbon group, a monovalent | monohydric alicyclic hydrocarbon group, a monovalent | monohydric aromatic hydrocarbon group etc. are mentioned, for example.

Examples of the monovalent chain hydrocarbon group include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, an sec-butyl group, an n-butyl group and an n-butyl group. Alkyl groups such as pentyl group;
Alkenyl groups such as ethenyl, propenyl, butenyl and pentenyl;
And alkynyl groups such as ethynyl group, propynyl group, butynyl group and pentynyl group.

As said monovalent | monohydric alicyclic hydrocarbon group, monocyclic cycloalkyl groups, such as a cyclopropyl group, cyclobutyl group, a cyclopentyl group, a cyclohexyl group etc .;
Polycyclic cycloalkyl groups such as norbornyl group, adamantyl group and the like;
Monocyclic cycloalkenyl groups such as cyclopropenyl group, cyclobutenyl group, cyclopentenyl group and cyclohexenyl group;
And polycyclic cycloalkenyl groups such as norbornenyl group.

Examples of the monovalent aromatic hydrocarbon group include aryl groups such as phenyl group, tolyl group, xylyl group, naphthyl group and anthryl group;
And aralkyl groups such as benzyl group, phenethyl group, phenylpropyl group and naphthylmethyl group.

  The said hetero atom containing group means group which has a bivalent or more hetero atom in a structure. The hetero atom-containing group may have one hetero atom, or may have two or more hetero atoms.

  The divalent or higher valence of the hetero atom-containing group is not particularly limited as long as it is a hetero atom having a divalent or higher valence, and examples thereof include an oxygen atom, a nitrogen atom, a sulfur atom, a silicon atom, and a phosphorus atom And boron atoms.

Examples of the hetero atom-containing group include groups consisting only of hetero atoms such as -O-, -SO-, -SO _2- , -SO ₂ O-, etc .;
-CO-, -COO-, -COS-, -CONH-, -OCOO-, -OCOS-, -OCONH-, -SCONH-, -SCSNH-, -SCSS-, etc. combining a carbon atom and a hetero atom Groups and the like.

As a substituent which substitutes one part or all part of the hydrogen atom of said group, halogen atoms, such as a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, for example;
Examples thereof include hydroxy, carboxy, amino, cyano, nitro, sulfonamide, oxo and the like.

As a C1-C20 monovalent organic group represented by said R < ² >, a C1-C20 monovalent hydrocarbon group is preferable among the above-listed groups, and a C1-C10 1 More preferred are hydrocarbon groups having a valence.

The monovalent chain organic group having 3 to 20 carbon atoms represented by R ^3, for example cyanoethyl group, a monovalent chain-like hydrocarbon group having 3 to 20 carbon atoms, the carbon of the chain hydrocarbon group -A group having a hetero atom-containing group at the end between carbons or at the side of the bond, and a group in which part or all of hydrogen atoms of these groups are substituted with a substituent, and the like. Examples of the monovalent chain hydrocarbon groups of 3 to 20 carbon atoms, for example, among those exemplified as the group represented by R ^2, and the like chain hydrocarbon group having 3 to 20 carbon atoms. The hetero atom-containing group and the substituent are the same as in the case of the group represented by R ² above.

Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms represented by R ^3, for example, among those exemplified as the group represented by R ^2, alicyclic having 3 to 20 carbon atoms carbide A hydrogen group etc. are mentioned.

The monovalent aliphatic heterocyclic group having 3 to 20 carbon atoms represented by R ³ includes, for example, a constituent atom of a linking group represented by —O—C (O) — as a constituent atom of the ring structure Lactone structure; Cyclic carbonate structure containing a constituent atom of the linking group represented by -O-C (O) -O- as a constituent atom of the ring structure; Cyclic ether in which one or more ether bonds are contained in part of the ring structure Structure; a cyclic sulfide structure in which one or more sulfide bonds are contained in part of the ring structure; a sultone structure containing a constituent atom of the linking group represented by -O-S (O ₂ )-as a constituent atom of the ring structure Examples thereof include groups having a ring structure, and groups obtained by substituting part or all of hydrogen atoms of these groups with a hydrocarbon group. As said hydrocarbon group, a C1-C20 monovalent hydrocarbon group illustrated as group represented by said R < ² > is preferable, and a C1-C10 monovalent hydrocarbon group is more preferable. When two or more of the hydrogen atoms are substituted with a hydrocarbon group, the two or more of the plurality of hydrocarbon groups are combined with one another and the atoms to which they are bonded or a part of the above ring structure and 3 to 10 ring members. May form a ring structure of

Examples of the monovalent hydrocarbon group which monovalent aliphatic heterocyclic carbon is substituted with a group having 1 to 20 3 to 20 carbon atoms represented by R ^3, for example the recited number from 3 to 20 carbon A C1-C20 monovalent hydrocarbon group etc. which were substituted by one or two or more groups among monovalent aliphatic heterocyclic groups are mentioned. Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms include such monovalent hydrocarbon group having 1 to 20 carbon atoms exemplified as the group represented by R ² are exemplified.

Further, R ³ may be a group containing an acid dissociable group. In this case, the solubility in the developer containing the organic solvent is increased by further increasing the polarity of the exposed area, so that the dissolution contrast between the exposed area and the non-exposed area can be further improved.

When R ³ is a group containing an acid dissociable group, examples of R ³ include a group represented by the following formula (2-1-a).

R < ³⁰ > is a methylene group or a C2-C10 alkylene group in said Formula (2-1-a). R ³¹ , R ³² and R ³³ are each independently an alkyl group having 1 to 10 carbon atoms, or two or more of these groups are combined together and formed together with the carbon atom to which they are attached It represents a part of the ring structure having 3 to 10 ring members. * Is a bonding site to the oxygen atom bonded to the adamantane ring.

The monovalent organic group having 1 to 20 carbon atoms represented by R ⁴ is not particularly limited as long as it is a group other than —OR ³ , and for example, those exemplified as the group represented by R ² above Similar groups and the like can be mentioned.

  As said p1, 1-4 are preferable and 1 and 2 are more preferable. As said p2, 0-4 are preferable and 0-2 are more preferable.

  As a specific example of group (I) represented by said Formula (2-1), group etc. which are represented by a following formula are mentioned, for example.

  Another preferable example in which the group (I) is an acid dissociable group is an acid dissociable group represented by the following formula (2-2). Even if this acid dissociable group is used, the same effect as the acid dissociable group represented by the above formula (2-1) can be obtained.

In the above formula (2-2), R ⁵ and R ⁶ each independently represent a monovalent organic group having 1 to 20 carbon atoms, or these groups are combined with each other together with the carbon atom to which they are bonded It represents a part of the ring structure having 3 to 20 ring members. R ⁷ and R ⁸ each independently represent a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. q1 is an integer of 0 to 5; When q1 is 2 or more, the plurality of R ⁷ may be the same or different, and the plurality of R ⁸ may be the same or different. Two or more of one or more of R ⁷ and one or more of R ⁸ together with the carbon atom or carbon chain to which these groups are combined to bind to each other form a ring structure having 3 to 20 rings. May be R ⁹ is substituted with cyanomethyl group, hydroxyethyl group, monovalent chain organic group having 3 to 20 carbon atoms, monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, cyano group or hydroxy group Carbon substituted with a C3-C20 monovalent alicyclic hydrocarbon group, a C3-C20 monovalent aliphatic heterocyclic group, or a C3-C20 monovalent aliphatic heterocyclic group It is a number 1-20 monovalent hydrocarbon group. q2 is an integer of 1-15. When q2 is 2 or more, a plurality of R ^{9 s} may be the same or different, and two or more of a plurality of -OR ⁹ are combined with each other and together with the carbon atom or carbon chain to which they are bonded, 3 to 20 ring members May form a ring structure of R ¹⁰ is a C 1-20 monovalent organic group other than —OR ⁹ or OO. q3 is an integer of 0-14. q3 is the case of 2 or more, the plurality of R ¹⁰ may be the same or different, ring members 3 to 20 together with the carbon atom or carbon chain two or more of the plurality of R ¹⁰ are combined they are bound to each other It may form a ring structure. However, q2 + q3 is 15 or less. * Shows the site | part couple | bonded with parts other than group (I) of structural unit (I).

As a C1-C20 monovalent organic group represented by said R < ⁵ >, R < ⁶ >, R < ⁷ > and R < ⁸ >, what was illustrated as group represented by R < ² > of said Formula (2-1), for example And the like. Among these, a C1-C20 monovalent hydrocarbon group is preferable, and a C1-C10 monovalent hydrocarbon group is more preferable.

Specific examples of the group represented by R ^9, for example, the type or the like same groups as those exemplified as the group represented by R ³ in (2-1) can be mentioned.

Further, R ⁹ may be a group containing an acid dissociable group. In this case, the solubility in the developer containing the organic solvent is increased by further increasing the polarity of the exposed area, so that the dissolution contrast between the exposed area and the non-exposed area can be further improved.

When R ⁹ is a group containing an acid dissociable group, examples of R ⁹ include a group represented by the above formula (2-1-a).

The monovalent organic group having 1 to 20 carbon atoms, which is represented by R ¹⁰ above, is not particularly limited as long as it is a group other than —OR ⁹ , and it is represented, for example, by R ² of the above formula (2-1) And the same groups as those exemplified as the group.

  As said q1, 0 is preferable. As said q2, 1-4 are preferable and 1 and 2 are more preferable. As said q3, 0-4 are preferable and 0-2 are more preferable.

  As a specific example of group (I) represented by said Formula (2-2), group etc. which are represented by a following formula are mentioned, for example.

  As another preferable example in case group (I) is an acid dissociative group, the acid dissociative group represented by following formula (3) is mentioned. Even if this acid dissociable group is used, the same effect as the acid dissociable group represented by the above formula (2-1) can be obtained, and an oxygen atom is present between the site dissociable by the action of acid and the adamantane ring. Being present, the mobility of the group (I) can be moderately improved. Thereby, the diffusion length of the acid generated from the [B] acid generator can be more appropriately controlled.

In the formula ^{(3), R 11} and ^{R 12} is a monovalent organic group having 1 to 20 carbon atoms independently. R ¹³ is a C 1-20 monovalent organic group or OO. r is an integer of 0 to 15; when r is 2 or more, plural R ¹³ may be the same or different, ring members 3 to 20 together with the carbon atom or carbon chain two or more of the plurality of R ¹³ are combined they are bound to each other It may form a ring structure. L ¹ is a single bond or a divalent organic group having 1 to 20 carbon atoms. Two or more of R ¹¹ , R ¹² and L ¹ may be combined with each other to form a ring structure having 3 to 20 ring members with the carbon atom to which they are attached. * Shows the site | part couple | bonded with parts other than group (I) of structural unit (I).

As a C1-C20 monovalent organic group represented by said R < ¹¹ >, R < ¹² > and R < ¹³ >, it is the same as what was illustrated as group represented by R < ² > of said Formula (2-1), for example And the like. Among these, a C1-C20 monovalent hydrocarbon group is preferable, and a C1-C10 monovalent hydrocarbon group is more preferable.

Examples of the divalent organic group having 1 to 20 carbon atoms represented by ^{L 1,} for example from the equation monovalent organic group exemplified having 1 to 20 carbon atoms as in ^{R 2} 1 one of (2-1) A group etc. except a hydrogen atom are mentioned. Among these, a C1-C20 bivalent hydrocarbon group is preferable, and a C1-C10 bivalent hydrocarbon group is more preferable.

  As said r, 0-4 are preferable and 0-2 are more preferable.

  As a specific example of group (I) represented by said Formula (3), group etc. which are represented by a following formula are mentioned, for example.

  When group (I) is represented by said Formula (2-1), Formula (2-2), or Formula (3), as structural unit (I), the structural unit etc. which are represented by a following formula are mentioned, for example Be

In said formula, Y ¹ is group (I) represented by said Formula (2-1), Formula (2-2), or Formula (3). The formula (2-1), (2-2) and formula (3) in the * indicates the binding site to the ester group adjacent to ^{Y 1.}

When the group (I) is not an acid dissociable group, a bulky adamantane ring is not detached in the exposed portion, so that the shrinkage of the resist film in PEB can be suppressed more effectively. In the present specification, the above “when the group (I) is not an acid dissociable group” means that the portion containing the adamantane ring is not eliminated by the action of an acid. Therefore, even when R ¹ in the substituent represented by the above formula (1) bonded to the adamantane ring contains an acid dissociable group, as long as the portion containing the adamantane ring is not eliminated by the action of acid, “group “(I) is not an acid dissociable group”.

  As such a group (I) which is not an acid dissociable group, a group represented by the following formula (4-1) is preferable from the viewpoint of further suppressing the shrinkage of the resist film and the viewpoint of further improving LWR and the like.

In the formula ^{(4-1), R 14} and ^{R 15} are each independently a hydrogen atom, a fluorine atom, a monovalent organic group for a hydroxy group or a C 1-20. s1 is an integer of 0-5. When s1 is 2 or more, the plurality of R ¹⁴ may be the same or different, and the plurality of R ¹⁵ may be the same or different. Two or more of one or more of R ¹⁴ and one or more of R ¹⁵ together with the carbon atom or carbon chain to which these groups are combined to bind to each other form a ring structure having 3 to 20 rings. May be R ¹⁶ is a C 1-20 monovalent organic group. s2 is an integer of 1-14. When s2 is 2 or more, a plurality of R ¹⁶ may be the same or different, and two or more of a plurality of -OR ¹⁶ are combined with each other and together with the carbon atom or carbon chain to which they are bonded, 3 to 20 ring members May form a ring structure of R ¹⁷ is a C 1-20 monovalent organic group other than —OR ¹⁶ or OO. s3 is an integer of 0 to 13. If s3 is 2 or more, plural R ¹⁷ may be the same or different, ring members 3 to 20 together with the carbon atom or carbon chain, two or more are combined they are bound to each other of the plurality of R ¹⁷ It may form a ring structure. However, s2 + s3 is 14 or less. * 1 shows the site | part couple | bonded with parts other than group (I) of structural unit (I). * 2 shows the site | part which couple | bonds with the structural unit adjacent to structural unit (I).

As a C1-C20 monovalent organic group represented by said R <^14> , R < ¹⁵ > and R < ¹⁶ >, it is the same as what was illustrated as group represented by R < ² > of said Formula (2-1), for example And the like.

Further, R ¹⁶ may be a group containing an acid dissociable group. In this case, the polarity of the part containing the adamantane ring in the exposed part is increased, and it becomes poorly soluble in the developer containing the organic solvent, whereby a negative resist pattern can be obtained.

When R ¹⁶ is a group containing an acid dissociable group, examples of R ¹⁶ include a group represented by the above formula (2-1-a).

The monovalent organic group having 1 to 20 carbon atoms represented by R ¹⁷ is not particularly limited as long as it is a group other than —OR ¹⁶ , and is represented, for example, by R ² of the above formula (2-1) And the same groups as those exemplified as the group.

  As said s1, 1 and 2 are preferable. As said s2, 1-4 are preferable and 1 and 2 are more preferable. As said s3, 0-4 are preferable and 0-2 are more preferable.

  The structural unit adjacent to the structural unit is the structural unit (I) when the structural units (I) are adjacent to each other, and the structural unit (I) is adjacent to another structural unit. It is another structural unit. The same applies to a group represented by the following formula (4-2) described later.

  As a specific example of group (I) represented by said Formula (4-1), group etc. which are represented by a following formula are mentioned, for example.

  Another preferable example in which the group (I) is not an acid dissociable group is a group represented by the following formula (4-2). Even when this group is used, the same effect as that of the group represented by the above formula (4-1) can be obtained.

In the above formula ^{(4-2), R 18} and ^{R 19} are each independently a hydrogen atom, a fluorine atom, a monovalent organic group for a hydroxy group or a C 1-20. t1 is an integer of 0-5. When t1 is 2 or more, the plurality of R ¹⁸ may be the same or different, and the plurality of R ¹⁹ may be the same or different. Two or more of one or more of R ¹⁸ and one or more of R ¹⁹ together with the carbon atom or carbon chain to which these groups are combined to form a ring having 3 to 20 ring members May be R ²⁰ is a monovalent organic group having 1 to 20 carbon atoms. L ² is a single bond or a divalent organic group having 1 to 20 carbon atoms. R ²⁰ and L ² may be combined with each other to form a ring structure having 3 to 20 ring members with a carbon atom to which they are bonded. R ²¹ is a monovalent organic group having 1 to 20 carbon atoms. t2 is an integer of 1-14. When t2 is 2 or more, a plurality of R ^{21 s} may be the same or different, and two or more of a plurality of -OR ²¹ may be combined with each other and the carbon atom or carbon chain to which they are bonded together has 3 to 20 ring members May form a ring structure of R ²² is a C 1-20 monovalent organic group other than —OR ²¹ or OO. t3 is an integer of 0 to 13. For t3 is 2 or more, plural R ²² may be the same or different, ring members 3 to 20 together with the carbon atom or carbon chain two or more of the plurality of R ²² are combined they are bound to each other It may form a ring structure. However, t2 + t3 is 14 or less. * 1 shows the site | part couple | bonded with parts other than group (I) of structural unit (I). * 2 shows the site | part which couple | bonds with the structural unit adjacent to structural unit (I).

The monovalent organic group of the ^{R 18,} R ^{19, R 20} and having 1 to 20 carbon atoms represented by ^{R 21,} for example, those exemplified as the groups represented by ^{R 2} in the formula (2-1) And the like.

Further, R ²¹ may be a group containing an acid dissociable group. In this case, the polarity of the part containing the adamantane ring in the exposed part is increased, and it becomes poorly soluble in the developer containing the organic solvent, whereby a negative resist pattern can be obtained.

When R ²¹ is a group containing an acid dissociable group, examples of R ²¹ include a group represented by the above formula (2-1-a).

Monovalent organic above ^L divalent organic group having 1 to 20 carbon atoms represented by ^2, for example, the formula (2-1) carbon atoms exemplified as the group represented by ^{R 2} of 20 Examples thereof include groups in which one hydrogen atom has been removed from the group. Among these, a C1-C20 bivalent hydrocarbon group is preferable, and a C1-C10 bivalent hydrocarbon group is more preferable.

The ester group located between L ² and the adamantane ring is preferably bonded to the 1-position carbon atom constituting the adamantane ring or to the 2-position secondary carbon atom.

The monovalent organic group having 1 to 20 carbon atoms represented by R ²² is not particularly limited as long as it is a group other than —OR ²¹ , and for example, it is represented by R ² of the above formula (2-1) And the same groups as those exemplified as the group.

  As said t1, 1 and 2 are preferable. As said t2, 1-4 are preferable and 1 and 2 are more preferable. As said t3, 0-4 are preferable and 0-2 are more preferable.

  As a specific example of group (I) represented by said Formula (4-2), group etc. which are represented by a following formula are mentioned, for example.

  When group (I) is represented by said Formula (4-1) or Formula (4-2), as structural-unit (I), the structural unit etc. which are represented by a following formula are mentioned, for example.

In the above formulae, R ^Y1 and R ^Y2 are each independently a hydrogen atom or a methyl group. Y ² is a group represented by Formula (4-1) or Formula (4-2) above. * 1 in the said Formula (4-1) and Formula (4-2) shows the coupling | bonding site | part to the carbon atom to which ^RY1 and ^RY2 couple ^| bond. * 2 in the said Formula (4-1) and Formula (4-2) shows the coupling | bonding site | part to the structural unit adjacent to Structural-unit (I).

  The lower limit of the content ratio of the structural unit (I) is preferably 1 mol%, more preferably 2 mol%, still more preferably 5 mol%, based on all structural units constituting the polymer [A]. Moreover, as an upper limit of the said content rate, 80 mol% is preferable, 50 mol% is more preferable, and 20 mol% is more preferable. By making the content rate of structural unit (I) into the said specific range, shrinkage of a resist film can be suppressed more and LWR etc. can be improved more.

[Structural unit (II)]
[A] The polymer may have a structural unit (II) containing an acid dissociable group. Examples of the structural unit (II) include structural units represented by the following formula (5). The structural unit (II) does not contain the group (I).

In said Formula (5), ^R35 is a hydrogen atom or a methyl group. R ³⁶ is a monovalent acid dissociable group.

As said R ^<35> , a hydrogen atom is preferable.

Examples of the monovalent acid-dissociable group represented by the above R ³⁶ include t-butyl group, 1-methylcyclopentyl group, 1-ethylcyclopentyl group, 2-methyladamantyl group, 2-ethyladamantyl group and the like. .

  Examples of the monomer giving the structural unit (II) include t-butyl (meth) acrylate, 1-methylcyclopentyl (meth) acrylate, 1-ethylcyclopentyl (meth) acrylate, 2-methacrylic acid (meth) acrylate Methyl adamantyl, 2-ethyl adamantyl (meth) acrylate, etc. are mentioned.

  When the polymer (A) has a structural unit (II), the lower limit of the content ratio of the structural unit (II) is preferably 10 mol%, based on all structural units constituting the polymer (A), The mole% is more preferable, and 30 mole% is more preferable. Moreover, as an upper limit of the said content rate, 80 mol% is preferable, 70 mol% is more preferable, and 60 mol% is more preferable. If the content of the structural unit (II) exceeds 80 mol%, the dry etching resistance may be insufficient.

[Structural unit (III)]
[A] The polymer preferably further has a structural unit having a lactone structure, a cyclic carbonate structure, a sultone structure or a combination thereof (hereinafter also referred to as “structural unit (III)”). [A] When the polymer further includes the structural unit (III), the basic resist characteristics such as the adhesion between the resist film and the substrate can be further improved. In addition, the solubility of the resist film in the developer can be enhanced. Structural unit (III) does not include group (I).

  As structural unit (III) which has the said lactone structure, the structural unit etc. which are represented by a following formula are mentioned, for example.

In the above formula, R ^L1 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

  As structural unit (III) which has the said cyclic carbonate structure, the structural unit etc. which are represented by a following formula are mentioned, for example.

In the above formula, R ^L1 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

  As structural unit (III) which has the said sultone structure, the structural unit etc. which are represented by a following formula are mentioned, for example.

In the above formula, R ^L1 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

  When the polymer [A] has the structural unit (III), the lower limit of the content ratio of the structural unit (III) is preferably 10 mol%, based on all structural units constituting the [A] polymer, The mole% is more preferable, and 20 mole% is more preferable. Moreover, as an upper limit of the said content rate, 80 mol% is preferable, 70 mol% is more preferable, and 60 mol% is more preferable. By making the content rate of structural unit (III) into the said specific range, the adhesiveness of a resist film and a board | substrate and the solubility to the developing solution of a resist film can be improved more.

[Other structural unit]
[A] The polymer may have other structural units in addition to the structural units (I) to (III). Examples of the other structural units include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, n-butyl (meth) acrylate, and the like (Meth) acrylic acid 2-methylpropyl, (meth) acrylic acid 1-methylpropyl, (meth) acrylic acid n-pentyl, (meth) acrylic acid n-hexyl, (meth) acrylic acid 2-ethylhexyl, (meth) 2-Hydroxyethyl acrylate, 2-hydroxy-n-propyl (meth) acrylate, 3-hydroxy-n-propyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, (meth) (Meth) acrylics such as 1-methyl-2-adamantyl acrylate, 1-ethyl-2-adamantyl (meth) acrylate Acid esters;
Unsaturated carboxylic acids (anhydrides) such as (meth) acrylic acid, crotonic acid, maleic acid, maleic anhydride, fumaric acid, cinnamic acid and the like;
Carboxyalkyl esters of unsaturated carboxylic acids such as 2-carboxyethyl (meth) acrylate, 2-carboxy-n-propyl (meth) acrylate, 3-carboxy-n-propyl (meth) acrylate;
Unsaturated nitrile compounds such as (meth) acrylonitrile, α-chloroacrylonitrile, croton nitrile, maleic nitrile, fumaronitrile and the like;
Unsaturated amide compounds such as (meth) acrylamide, N, N-dimethyl (meth) acrylamide, crotonamide, maleic amide, fumaramide;
Unsaturated imide compounds such as maleimide, N-phenyl maleimide, N-cyclohexyl maleimide and the like;
Derived from monomers such as nitrogen-containing vinyl compounds such as N-vinyl-ε-caprolactam, N-vinylpyrrolidone, 2-vinylpyridine, 3-vinylpyridine, 4-vinylpyridine, 2-vinylimidazole, 4-vinylimidazole and the like Structural unit (IV). The structural unit (IV) does not contain the group (I).

  The upper limit of the content ratio of the structural unit (IV) is usually 25 mol%, preferably 15 mol%, based on all structural units constituting the polymer [A]. When the content rate of structural unit (IV) exceeds the said upper limit, the resolution of the resist pattern formed may fall.

<[A] Synthesis Method of Polymer>
[A] The polymer can be produced, for example, by polymerizing a monomer corresponding to each predetermined structural unit in a suitable solvent using a radical initiator. For example, a method in which a solution containing a monomer and a radical initiator is added dropwise to a reaction solvent or a solution containing a monomer to cause a polymerization reaction; a solution containing a monomer and a solution containing a radical initiator Separately by adding the reaction solvent or the solution containing the monomers to the polymerization reaction; plural kinds of solutions containing the respective monomers and the solution containing the radical initiator It is preferable to synthesize | combine by methods, such as the method of dripping to the solution containing a solvent or a monomer, and making a polymerization reaction.

  The resin obtained by the polymerization reaction is preferably recovered by reprecipitation. That is, after completion of the polymerization reaction, the target resin is recovered as powder by charging the polymerization solution into the reprecipitation solvent. As the reprecipitation solvent, alcohols and alkanes can be used alone or in combination of two or more. Other than the reprecipitation method, low molecular weight components such as monomers and oligomers can be removed by liquid separation operation, column operation, ultrafiltration operation or the like to recover the resin.

  [A] The lower limit of the polystyrene equivalent weight average molecular weight (Mw) by gel permeation chromatography (GPC) of the polymer is preferably 1,000, more preferably 2,000, and still more preferably 3,000. Moreover, as an upper limit of said Mw, 50,000 are preferable, 40,000 are more preferable, 30,000 are more preferable. [A] By making Mw of a polymer more than the said lower limit, the heat resistance when it is set as a resist can be improved. On the other hand, by setting the Mw of the polymer [A] to the above upper limit or less, the developability when used as a resist can be improved.

  The lower limit of the ratio (Mw / Mn) of the Mw to the polystyrene-equivalent number average molecular weight (Mn) of the [A] polymer by GPC is usually 1. Moreover, as an upper limit of the said ratio (Mw / Mn), 5 is preferable, 3 is more preferable, and 2 is more preferable. By setting Mw / Mn in the above range, the resist film becomes excellent in resolution performance.

  Mw and Mn in the present specification, for example, using a Tosoh GPC column (two G2000HXL, one G3000HXL, one G4000HXL), under the analysis conditions of flow rate 1.0 mL / min, elution solvent tetrahydrofuran, column temperature 40 ° C. The value is measured by GPC using monodispersed polystyrene as a standard.

  The lower limit of the content of the polymer [A] in the radiation sensitive resin composition (I) is preferably 70% by mass, based on the total solids (the total mass of components other than the [C] solvent), and 80% by mass. % Is more preferable, and 90% by mass is further preferable. Moreover, as an upper limit of the said content, 99 mass% is preferable. By setting the content ratio of the polymer [A] to the above specific range, the shrinkage of the resist film can be further suppressed, and LWR and the like can be further improved. The polymer [A] may be used alone or in combination of two or more.

<[B] acid generator>
[B] The acid generator generates an acid upon exposure to light, and the acid causes the acid dissociable group present in the polymer [A] to dissociate. As a result, the polarity of the polymer [A] is increased. The form of the [B] acid generator contained in the radiation sensitive resin composition (I) is heavy even in the form of a compound as described later (hereinafter sometimes referred to as "[B] acid generator" as appropriate). It may be in the form of being incorporated as a part of coalescence or both of these forms.

  Examples of the acid generator (B) include onium salt compounds, N-sulfonyloxyimide compounds, halogen-containing compounds, and diazoketone compounds. Of these [B] acid generators, onium salt compounds are preferred.

  Examples of the onium salt compounds include sulfonium salts (including tetrahydrothiophenium salts), iodonium salts, phosphonium salts, diazonium salts, pyridinium salts and the like.

  As a sulfonium salt, for example, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, triphenylsulfonium perfluoro-n-octanesulfonate, triphenylsulfonium 2-bicyclo [2.2.1] hept- 2-yl-1,1,2,2-tetrafluoroethanesulfonate, triphenylsulfonium camphorsulfonate, 4-cyclohexylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-cyclohexylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate, 4-cyclohexyl Phenyl diphenyl sulfonium perfluoro-n-octane sulfonate, 4-cyclohexylphenyl dipheny Sulfonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethane sulfonate, 4-cyclohexylphenyl diphenyl sulfonium camphor sulfonate, 4-methanesulfonyl phenyl diphenyl sulfonium trifluoromethane sulfonate, 4-methanesulfonylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium perfluoro-n-octanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium 2-bicyclo [2.2.1] hept-2 -Yl-1,1,2,2-tetrafluoroethanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium camphorsulfonate, toffee Ruhosuhoniumu 1,1,2,2-tetrafluoro-6- (1-adamantanecarbonyloxy) - hexane-1-sulfonate, and the like. Among these sulfonium salts, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate and triphenylphosphonium 1,1,2,2-tetrafluoro-6- (1-adamantanecarbonyloxy)- Hexane-1-sulfonate is preferred.

  Examples of tetrahydrothiophenium salts include 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium nona Fluoro-n-butanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophen -Bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium camphorsulfonate , 1- (6-n-butoxynaphthalen-2-yl) Trahydrothiophenium trifluoromethanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydro Thiophenium perfluoro-n-octane sulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothiophenium 2-bicyclo [2.2.1] hept-2-yl-1,1,2 , 2-tetrafluoroethane sulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothiophenium camphorsulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium trifluoromethanesulfonate , 1- (3,5-dimethyl-4) Hydroxyphenyl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (3,5-dimethyl-) 4-hydroxyphenyl) tetrahydrothiophenium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethane sulfonate, 1- (3,5-dimethyl-4-hydroxyl) And phenyl) tetrahydrothiophenium camphorsulfonate and the like. Among these tetrahydrothiophenium salts, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) Tetrahydrothiophenium perfluoro-n-octane sulfonate and 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium nonafluoro-n-butane sulfonate are preferred.

  Examples of iodonium salts include diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium perfluoro-n-octanesulfonate, diphenyliodonium 2-bicyclo [2.2.1] hept-2-yl- 1,1,2,2-tetrafluoroethanesulfonate, diphenyliodonium camphorsulfonate, bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate, Bis (4-t-butylphenyl) iodonium perfluoro-n-octanesulfonate, bis (4-t-butylphenyl) iodonium 2-bicyclo [2.2 1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, bis (4-t- butylphenyl) iodonium camphorsulfonate, and the like. Among these iodonium salts, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate is preferred.

Examples of the N-sulfonyloxyimide compound include N- (trifluoromethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (nonafluoro-n-butanesulfonyloxy) ) Bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (perfluoro-n-octanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2 , 3-dicarboximide, N- (2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonyloxy) bicyclo [2.2.1] hept- 5-ene-2,3-dicarboximide, N- (2- (3- tetracyclo ^[4.4.0.1 2,5 ^{.1 7,10]} dodecanyl) -1,1-difluoro-ethanone Sulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (camphorsulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3 -Dicarboximide etc. are mentioned. Among these N-sulfonyloxyimide compounds, N- (trifluoromethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide is preferred.

  Moreover, in order to shorten the diffusion length of an acid appropriately by interaction with a polymer [A], using a [B] acid generator represented by the following formula (B-1) having an alicyclic structure Is preferred. By using a [B] acid generator represented by the following formula (B-1), the compatibility with the [A] polymer is enhanced, so the dispersibility of the [B] acid generator in the resist film is improved. It can also be done. [B] When the dispersibility of the acid generator is improved, the lithography properties of the resulting resist pattern can be further improved.

In Formula (B-1) above, Rf ¹ and Rf ² each independently represent a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 4 carbon atoms. n is an integer of 1 to 3; However, it is not the case that both Rf ¹ and Rf ² bonded to the carbon at the α-position of the sulfonate group are hydrogen atoms. When n is 2 or more, the plurality of Rf ¹ may be the same or different, and the plurality of Rf ² may be the same or different. R ^r is a C3-C20 monovalent organic group having an alicyclic structure. X ⁺ is a monovalent cation.

The fluorinated alkyl group having 1 to 4 carbon atoms represented by R f ¹ and R f ² includes, for example, fluoromethyl group, difluoromethyl group, trifluoromethyl group, fluoroethyl group, difluoroethyl group, trifluoroethyl group, Perfluoroethyl group, fluoropropyl group, difluoropropyl group, trifluoropropyl group, pentafluoropropyl group, hexafluoropropyl group, perfluoropropyl group, fluorobutyl group, difluorobutyl group, trifluorobutyl group, tetrafluorobutyl group And pentafluorobutyl group, perfluorobutyl group and the like.

The monovalent organic group having an alicyclic structure represented by R ^r is, for example, cyclopentyl group, cyclohexyl group, 1-norbornyl group, 2-norbornyl group, 1-norbornenyl group, 2-norbornenyl group, 1-adamantyl And 2-adamantyl group, furyl group, and an alkylene group such as a methylene group or ethylene group, propylene group, butylene group or the like to which these groups are bonded. Among these, a group having a polycyclic alicyclic structure such as a norbornyl group and an adamantyl group is preferable, and a group having an adamantyl group is more preferable.

One part or all part of the hydrogen atom which said R ^r has may be substituted by the substituent. Examples of this substituent include a hydroxy group, a carboxy group, an alkylcarbonyl group, a cyano group, a nitro group, a sulfonamide group, an oxo group and the like.

The monovalent organic group having an alicyclic structure represented by R ^r is preferably a group represented by the following formula (i).

In the above formula (i), A is a (m + 1) -valent linking group. m is an integer of 1 to 3; R ^r1 is a C3-C20 monovalent organic group having an alicyclic structure.

Examples of the (m + 1) -valent linking group represented by A above include, as a divalent linking group, an ester group, an ether group, a carbonyl group, an amido group, an imino group, an alkanediyl group, a cycloalkanediyl group, an arylene group And aralkylene groups.
Examples of the trivalent linking group include alkanetriyl group, cycloalkanetriyl group, arenetriyl group and the like.
Examples of the tetravalent linking group include alkanetetrayl group, cycloalkanetetrayl group, and arenetetrayl group.

As an example of a C3-C20 monovalent organic group which has the alicyclic structure represented by said R ^<r1 >, the example of said R ^<r > can be mentioned.

Examples of the cation represented by X ⁺ include onium cations including sulfur, iodine, phosphorus, nitrogen and the like, and specifically, sulfonium cations, tetrahydrothiophenium cations, iodonium cations, phosphonium cations, diazonium cations, Pyridinium cation etc. are mentioned. Among these, sulfonium cation and tetrahydrothiophenium cation are preferable, and sulfonium cation is more preferable.

  As a [B] acid generator represented by said Formula (B-1), the thing etc. which are represented by a following formula are mentioned.

In said formula, X ^<+> is synonymous with said formula (B-1).

  These [B] acid generators may be used alone or in combination of two or more. [B] The lower limit of the content when the acid generator is [B] acid generator is 0 with respect to 100 parts by mass of the polymer [A] from the viewpoint of securing the sensitivity and the developability as a resist. 1 part by mass is preferable, 0.5 parts by mass is more preferable, and 1 part by mass is more preferable. From the same viewpoint, the upper limit of the content is preferably 50 parts by mass, more preferably 40 parts by mass, and still more preferably 30 parts by mass.

<[C] solvent>
As the [C] solvent contained in the radiation sensitive resin composition (I), it is possible to dissolve or disperse at least the above-mentioned [A] polymer, [B] acid generator, and optional components added as needed. There is no limitation, and alcohol solvents, ketone solvents, amide solvents, ether solvents, ester solvents, mixed solvents of two or more of these, and the like can be used. Specific examples of the solvent [C] include the same solvents as those exemplified as the organic solvent which can be used in the developer in the above-mentioned developing step. Among these, propylene glycol monomethyl ether and cyclohexanone are preferable. These solvents may be used alone or in combination of two or more.

<[D] Acid Diffusion Controller>
The radiation sensitive resin composition (I) may contain a [D] acid diffusion controller. The acid diffusion controller [D] exerts an effect of suppressing an undesirable chemical reaction in the non-exposed area by controlling the diffusion phenomenon of the acid generated from the acid generator in the resist film by exposure [B]. In addition, since the storage stability of the radiation sensitive resin composition (I) is improved, it is possible to suppress the line width change of the resist pattern due to the change of the drawing time from exposure to development processing. Thereby, the radiation sensitive resin composition excellent in process stability is obtained. As a containing form of the [D] acid diffusion controlling body in the radiation sensitive resin composition (I), it is heavy even in the form of a free compound (hereinafter sometimes referred to as “[D] acid diffusion controlling agent” as appropriate). It may be in the form of being incorporated as a part of coalescence or both of these forms.

  Examples of the acid diffusion control agent (D) include amine compounds, amide group-containing compounds, urea compounds and nitrogen-containing heterocyclic compounds.

  Examples of amine compounds include mono (cyclo) alkylamines; di (cyclo) alkylamines; tri (cyclo) alkylamines; substituted alkylanilines and derivatives thereof; ethylenediamine, N, N, N ′, N′-tetra Methylethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylether, 4,4′-diaminobenzophenone, 4,4′-diaminodiphenylamine, 2,2-bis (4 -Aminophenyl) propane, 2- (3-aminophenyl) -2- (4-aminophenyl) propane, 2- (4-aminophenyl) -2- (3-hydroxyphenyl) propane, 2- (4-amino) Phenyl) -2- (4-hydroxyphenyl) propane, 1, -Bis (1- (4-aminophenyl) -1-methylethyl) benzene, 1,3-bis (1- (4-aminophenyl) -1-methylethyl) benzene, bis (2-dimethylaminoethyl) ether Bis (2-diethylaminoethyl) ether, 1- (2-hydroxyethyl) -2-imidazolidinone, 2-quinoxalinol, N, N, N ′, N′-tetrakis (2-hydroxypropyl) ethylenediamine, N, N, N ', N' 'N' '-pentamethyl diethylene triamine etc. are mentioned.

  Examples of the amide group-containing compound include N-t-butoxycarbonyl group-containing amino compounds, formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide, Benzamide, pyrrolidone, N-methylpyrrolidone, N-acetyl-1-adamantylamine, tris (2-hydroxyethyl) i-cyanurate and the like can be mentioned.

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

  The nitrogen-containing heterocyclic compounds include, for example, imidazoles; pyridines; piperazines; pyrazine, pyrazole, pyridazine, quinozalin, purine, pyrrolidine, piperidine, piperidine ethanol, 3-piperidino-1,2-propanediol, morpholine, 4- Methyl morpholine, 1- (4-morpholinyl) ethanol, 4-acetylmorpholine, 3- (N-morpholino) -1,2-propanediol, 1,4-dimethylpiperazine, 1,4-diazabicyclo [2.2.2 And the like.

  Further, as the [D] acid diffusion control agent, it is also possible to use a photodisintegrable base which is photosensitive upon exposure to generate a weak acid. An example of the photodisintegrable base is an onium salt compound which is decomposed by exposure to lose acid diffusion controllability. Examples of the onium salt compound include a sulfonium salt compound represented by the following formula (D1), an iodonium salt compound represented by the following formula (D2), and the like.

R < ⁴⁰ > -R < ⁴⁴ > is respectively independently a hydrogen atom, an alkyl group, an alkoxy group, a hydroxyl group, or a halogen atom in said Formula (D1) and Formula (D2). Z ^- is ^{OH -, R D -COO -,} R D -SO 3 - is an anion represented by or the following formula (D3). However, R ^D is an alkyl group, an aryl group or an alkaryl group.

In the above formula (D3), R ⁴⁵ is a linear or branched alkyl group having 1 to 12 carbon atoms in which a part or all of hydrogen atoms may be substituted with a fluorine atom, or 1 to 12 carbon atoms Or a linear or branched alkoxy group of u is an integer of 0 to 2;

  When the acid diffusion controller [D] is an acid diffusion controller, the content of the acid diffusion controller [D] is usually 5 parts by mass or less based on 100 parts by mass of the polymer [A]. . [D] If the content of the acid diffusion control agent exceeds 5 parts by mass, the sensitivity as a resist tends to decrease.

<Other ingredients>
The radiation sensitive resin composition (I) is a polymer other than the polymer [A] as another component, and contains a fluorine atom (hereinafter, also referred to as "[E] polymer"). , [F] An uneven distribution promoting agent, an alicyclic skeleton compound, and other components such as a surfactant may be contained.

[[E] polymer]
When the radiation sensitive resin composition (I) contains an [E] polymer, when the resist film is formed, the oil repellency characteristic of the [E] polymer in the film makes its distribution near the surface of the resist film Since there is a tendency to become unevenly distributed, it is possible to suppress the dissolution of the [B] acid generator, the [D] acid diffusion control agent, etc. at the time of immersion exposure to the immersion medium. Further, by the water repellency characteristic of the [E] polymer, the advancing contact angle between the resist film and the immersion medium can be controlled within a desired range, and the generation of bubble defects can be suppressed. Furthermore, since the receding contact angle between the resist film and the immersion medium is increased, high-speed scan exposure can be performed without leaving water droplets. Thus, when the radiation sensitive resin composition (I) contains the [E] polymer, a resist film suitable for immersion exposure can be formed.

  The polymer [E] is not particularly limited as long as it has a fluorine atom, but the fluorine atom content (mass%) is preferably higher than that of the polymer [A]. [A] Since the fluorine atom content rate is higher than that of the polymer, the degree of uneven distribution described above becomes higher, and the characteristics such as water repellency and elution suppression property of the obtained resist film are improved.

  [E] The polymer is formed by polymerizing one or more types of monomers containing a fluorine atom in the structure.

  As the monomer containing the fluorine atom in the structure, a monomer giving a polymer containing a fluorine atom in the main chain, a monomer giving a polymer containing a fluorine atom in the side chain, a main chain and a side chain And monomers giving a polymer containing a fluorine atom.

  Examples of the monomer giving a polymer containing a fluorine atom in the main chain include α-fluoroacrylate compounds, α-trifluoromethylacrylate compounds, β-fluoroacrylate compounds, β-trifluoromethylacrylate compounds, α, β- A fluoroacrylate compound, an alpha, beta- trifluoromethyl acrylate compound, a compound in which hydrogen of one or more vinyl moieties is substituted with a fluorine atom or a trifluoromethyl group, and the like can be mentioned.

  As a monomer giving a polymer containing a fluorine atom in the side chain, for example, a compound in which a fluorine atom or a fluoroalkyl group or a derivative thereof is bonded to a site not containing a double bond of an alicyclic olefin compound such as norbornene And ester compounds of acrylic acid or methacrylic acid with a fluoroalkyl group or a derivative thereof, and a compound in which a fluorine atom or a fluoroalkyl group or a derivative thereof is bonded to a site not containing a double bond of one or more olefins. Be

  As a monomer giving a polymer containing a fluorine atom in the main chain and side chain, for example, α-fluoroacrylic acid, β-fluoroacrylic acid, α, β-fluoroacrylic acid, α-trifluoromethylacrylic acid, An ester compound of β-trifluoromethyl acrylic acid, α, β-trifluoromethyl acrylic acid, etc. with a fluoroalkyl group or a derivative thereof, hydrogen of one or more vinyl sites is substituted by a fluorine atom or a trifluoromethyl group Or a compound in which a fluorine atom or a fluoroalkyl group or a derivative thereof is bonded to a site not containing a double bond of the compound, a hydrogen bonded to a double bond of one or more alicyclic olefin compounds What has a fluoroalkyl group or its derivative group couple | bonded with the site | part which is substituted with a fluoromethyl group and does not contain a double bond etc. are mentioned. In addition, the said alicyclic olefin compound shows the compound in which a part of ring is a double bond.

  [E] As a structural unit which a polymer has, the structural unit (Hereafter, it is also mentioned "a structural unit (FI)") represented by a following formula (F1) is mentioned.

In the above formula (F1), R ⁴⁶ is hydrogen, a fluorine atom, a methyl group or a trifluoromethyl group. E is a divalent linking group. R ⁴⁷ represents a linear or branched alkyl group having 1 to 6 carbon atoms or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms containing at least one or more fluorine atoms or a derivative thereof .

  Examples of the divalent linking group represented by E include a single bond, an oxygen atom, a sulfur atom, a carbonyloxy group, an oxycarbonyl group, an amido group, a sulfonylamide group, a urethane group and the like.

  As a monomer which gives a structural unit (F-I), trifluoromethyl (meth) acrylic acid ester, 2,2,2- trifluoroethyl (meth) acrylic acid ester, perfluoroethyl (meth) acrylic acid ester Perfluoro n-propyl (meth) acrylate, Perfluoro i-propyl (meth) acrylate, Perfluoro n-butyl (meth) acrylate, Perfluoro i-butyl (meth) acrylate, Per Fluoro t-butyl (meth) acrylate, 2- (1,1,1,3,3,3-hexafluoropropyl) (meth) acrylate, 1- (2,2,3,3,4,5 4,5,5-octafluoropentyl) (meth) acrylic acid ester, perfluorocyclohexylmethyl (meth) acrylic Ester, 1- (2,2,3,3,3-pentafluoropropyl) (meth) acrylic acid ester, 1- (3,3,4,4,5,5,6,6,7,7,8 , 8, 9, 9, 10, 10, 10-heptadecafluorodecyl) (meth) acrylic acid ester, 1- (5-trifluoromethyl-3,3,4,4,5,6,6,6- Octafluorohexyl) (meth) acrylic acid ester etc. are mentioned.

  [E] The polymer may contain only one type of structural unit (F-I), or may contain two or more types. The lower limit of the content ratio of the structural unit (F-I) is usually 5 mol%, preferably 10 mol%, more preferably 15 mol%, based on 100 mol% of all structural units in the polymer [E]. is there. If the content ratio of the structural unit (F-I) is less than the above lower limit, a receding contact angle of 70 degrees or more may not be achieved.

  As a minimum of Mw of [E] polymer, 1,000 is preferred. Moreover, as an upper limit of said Mw, 50,000 are preferable, 30,000 are more preferable, and 10,000 are more preferable. [E] A sufficient advancing contact angle can be obtained by setting the Mw of the polymer to the above lower limit or more. On the other hand, by making Mw below the above-mentioned upper limit, the developability at the time of using it as a resist can be improved.

  The lower limit of the ratio (Mw / Mn) of Mw to Mn of the polymer (E) is usually 1. Moreover, as an upper limit of the said ratio (Mw / Mn), 3 is preferable and 2 is more preferable.

  [E] The polymer can be synthesized, for example, by polymerizing monomers giving the given structural units in a suitable solvent, using a radical initiator.

  When radiation sensitive resin composition (I) contains an [E] polymer, as a lower limit of content of a [E] polymer, 0.1 mass parts is preferred to 100 mass parts of [A] polymers. 1 part by mass is more preferable, and 2 parts by mass is more preferable. Moreover, as an upper limit of the said content, 20 mass parts is preferable, 10 mass parts is more preferable, 5 mass parts is more preferable. When the content of the [E] polymer in the radiation sensitive resin composition (I) is in the above range, the water repellency and the dissolution suppressing property of the obtained resist film surface can be further enhanced.

[[F] uneven distribution promoter]
The radiation sensitive resin composition (I) may contain a [F] uneven distribution promoting agent. [F] The uneven distribution promoting agent has an effect of segregating the [E] polymer on the resist film surface more efficiently when the radiation sensitive resin composition (I) contains the [E] polymer. It is a thing. When the radiation sensitive resin composition (I) contains the [F] uneven distribution promoting agent, the amount of the [E] polymer added can be smaller than that of the prior art. Therefore, the elution of the components from the resist film to the immersion liquid can be further suppressed without impairing the LWR performance, or the immersion exposure can be performed at high speed by high-speed scanning, resulting in the watermark defect as a result. And so forth can be effectively suppressed. [F] Examples of the uneven distribution promoting agent include low molecular weight compounds having a relative dielectric constant of 30 or more and 200 or less and a boiling point at 1 atmospheric pressure of 100 ° C. or more. Specific examples of such compounds include lactone compounds, carbonate compounds, nitrile compounds, polyhydric alcohols and the like.

  Examples of the lactone compound include γ-butyrolactone, valerolactone, mevalonic lactone, norbornane lactone and the like. As said carbonate compound, a propylene carbonate, ethylene carbonate, a butylene carbonate, vinylene carbonate etc. are mentioned, for example. Examples of the nitrile compound include succinonitrile and the like. Examples of the polyhydric alcohol include glycerin and the like.

  [F] The ubiquitination promoter is preferably a lactone compound, and more preferably γ-butyrolactone, from the viewpoint of more effectively suppressing the immersion-induced defects.

  When the radiation sensitive resin composition (I) contains a [F] uneven distribution promoting agent, the lower limit of the content of the [F] uneven distribution promoting agent is the polymer of the radiation sensitive resin composition (I) 10 parts by mass is preferable, 15 parts by mass is more preferable, 20 parts by mass is more preferable, and 25 parts by mass is particularly preferable based on 100 parts by mass of the total amount. Moreover, as an upper limit of content of a [F] uneven distribution promoter, 500 mass parts is preferable, 300 mass parts is more preferable, 250 mass parts is more preferable, 200 mass parts is especially preferable. [F] When the content of the uneven distribution promoting agent is in the above range, the immersion-induced defects can be further effectively suppressed.

[Alicyclic skeleton compound]
When the radiation sensitive resin composition (I) contains the above-mentioned alicyclic skeleton compound, dry etching resistance, pattern shape, adhesion to a substrate, and the like can be further improved. Examples of alicyclic skeleton compounds include adamantane derivatives such as 1-adamantane carboxylic acid, 2-adamantanone, t-butyl 1-adamantane carboxylic acid; t-butyl deoxycholate, t-butoxycarbonylmethyl deoxycholate, Deoxycholic acid esters such as 2-ethoxyethyl deoxycholic acid; Lithocholic acid esters such as t-butyl lithocholic acid, t-butoxycarbonylmethyl lithocholic acid, 2-ethoxyethyl lithocholic acid; 3- [2-hydroxy-2 , 2-Bis (trifluoromethyl) ethyl] tetracyclo [4.4.0.1 ^2,5 . ^17,10 ] dodecane, 2-hydroxy-9-methoxycarbonyl-5-oxo-4-oxa-tricyclo [4.2.1.0 ^3,7 ] nonane and the like.

[Surfactant]
When the radiation sensitive resin composition (I) contains the above-mentioned surfactant, coating properties, striation, developability and the like can be further improved. As surfactant, for example, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyethylene glycol dilaurate, polyethylene glycol di Nonionic surfactants, such as stearate, etc. are mentioned.

  As content of surfactant in radiation sensitive resin composition (I), it is 1 mass part or less normally with respect to 100 mass parts of [A] polymer.

<Method of Preparing Radiation-Sensitive Resin Composition (I)>
The radiation sensitive resin composition (I) can be prepared, for example, by mixing the [A] polymer, the [B] acid generator, the [C] solvent and an optional component in a predetermined ratio. As a minimum of concentration of solid content (components other than a [C] solvent) in a composition at the time of mixing, 0.1 mass% is preferred, 0.5 mass% is more preferable, and 1 mass% is more preferable. Moreover, as an upper limit of the said density | concentration, 50 mass% is preferable, 30 mass% is more preferable, and 10 mass% is more preferable. The radiation sensitive resin composition (I) is prepared, for example, by filtration with a filter having a pore diameter of about 0.2 μm when used.

Radiation-sensitive resin composition
The radiation sensitive resin composition of the present invention is a radiation sensitive resin composition containing a polymer, a radiation sensitive acid generator, and a solvent, the solubility of which in an organic solvent is reduced by the action of an acid. The polymer is characterized by having a structural unit containing a first acid dissociable group represented by the formula (2-1), the formula (2-2) or the formula (3). .

  Another radiation sensitive resin composition of the present invention is a radiation sensitive resin composition comprising a polymer whose solubility in a developer containing an organic solvent is reduced by the action of an acid, a radiation sensitive acid generator, and a solvent. The polymer is characterized by having a structural unit containing a first group represented by the above formula (4-1) or the above formula (4-2).

  By using the radiation sensitive resin composition in a resist pattern forming method of developing with a developer containing an organic solvent, it is possible to suppress the shrinkage of the resist film while improving the optical contrast while improving the LWR and the like. be able to. Since the said radiation sensitive resin composition is demonstrated as radiation sensitive resin composition (I) in the said resist pattern formation method, description is abbreviate | omitted here.

  EXAMPLES Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples. In addition, each measurement in an Example and a comparative example was performed by the following method.

[Weight average molecular weight (Mw) and number average molecular weight (Mn)]
Using Tosoh GPC column (G2000HXL: 2 columns, G3000HXL: 1 column, G4000HXL: 1 column), flow rate: 1.0 mL / min, elution solvent: tetrahydrofuran, sample concentration: 1.0% by mass, sample injection amount: 100 μL, column temperature: 40 ° C., detector: Measured by gel permeation chromatography (GPC) using monodispersed polystyrene as a standard under analysis conditions of a differential refractometer. Moreover, dispersion degree (Mw / Mn) was computed from the measurement result of Mw and Mn.

[ ¹³ C-NMR analysis]
Using “JNM-ECX400” manufactured by JEOL Ltd., analysis was carried out to determine the content ratio (mol%) of each structural unit in each polymer using deuterated chloroform as the measurement solvent.

<Synthesis of Compound>
Synthesis Example 1 Synthesis of Compound (M-1)
In a 1,000 mL round bottom flask, 20.0 g (120 mmol) of 5-hydroxy-2-adamantanone, 18.3 g (180 mmol) of triethylamine, and 200 mL of dichloromethane were added and stirred in a water bath. The methanesulfonyl chloride 17.9g (180 mmol) was dripped slowly there. After the dropwise addition, the reaction was stirred at room temperature for 10 hours and quenched by adding water. The organic layer was washed twice with an aqueous sodium hydrogen carbonate solution and once with an aqueous oxalic acid solution, and then purified by column chromatography to obtain a compound (m-1) represented by the following formula (yield 24.3 g, Rate 83%). Then, 20.0 g (81.9 mmol) of compound (m-1), 13.7 g (90.0 mmol) of diazabicycloundecene (DBU), and 2,2-dimethyl-1, 2,0-dimethyl-1 in a 500 mL round bottom flask 32.5 g (246 mmol) of 3-dioxolane-4-methanol were added, and the mixture was heated and stirred at 145 ° C. for 10 hours. After cooling to room temperature, 250 mL of dichloromethane and 200 mL of water were added and vigorously stirred for 10 minutes. The organic layer was collected, washed with water four times, and then purified by column chromatography to obtain a compound (m-2) represented by the following formula (yield 15.6 g, 68%). Then, 15.2 g (54.2 mmol) of the compound (m-2) and 75 mL of tetrahydrofuran were added to a 500 mL round bottom flask and stirred in a water bath. Thereto, 75.9 mL of a 1 M solution of methylmagnesium bromide in tetrahydrofuran was slowly dropped. After completion of the dropwise addition, the mixture was stirred at room temperature for 1.5 hours and then at 60 ° C. for 8 hours. After quenching the reaction with an aqueous ammonium chloride solution, ethyl acetate was added and washing with water was carried out three times. By evaporating the solvent, a crude product of a compound (m-3) represented by the following formula was obtained (yield: 16.0 g). The compound (m-3) was used in the next reaction without further purification. In a 500 mL round bottom flask, 16.0 g (54.0 mmol) of a crude compound (m-3), 6.55 g (64.8 mmol) of triethylamine, 1,4-diazabicyclo [2.2.2] octane (DABCO) ) 1.82 g (16.2 mmol) and 150 mL of acetonitrile were added and stirred in a water bath. The methacryloyl chloride 8.46g (81.0 mmol) was dripped slowly there. After the dropwise addition, the mixture was stirred at room temperature for 10 hours, and water was added to stop the reaction. After washing twice with an aqueous sodium hydrogen carbonate solution, purification by column chromatography gave a compound (M-1) represented by the following formula (yield 13.6 g, 69%).

Synthesis Examples 2 to 24 (Synthesis of Compounds (M-2) to (M-24))
By appropriately selecting the precursor and performing the same operation as in Synthesis Example 1, the compounds (M-2) to (M-24) represented by the following formulas were synthesized.

Synthesis Example 25 Synthesis of Compound (M-25)
The compound (M-25) represented by the following formula was synthesized in the same manner as in Synthesis Example 1 except that the above compound (m-1) was reacted with 3-methyl-1,3-butanediol .

Synthesis Examples 26 to 50 (Synthesis of Compounds (M-26) to (M-50))
By appropriately selecting the precursor and performing the same operation as in Synthesis Example 25, compounds (M-26) to (M-50) represented by the following formulas were synthesized.

Synthesis Example 51 Synthesis of Compound (M-51)
In a 300 mL round bottom flask, 8.67 g (120 mmol) of zinc powder and 80 mL of tetrahydrofuran were added and stirred at room temperature. Thereto, 0.05 g of trimethylsilyl chloride was added, and the mixture was stirred at room temperature for 20 minutes to activate zinc. Then, a solution of 22.0 g (78.5 mmol) of the compound (m-2) and 19.7 g (102 mmol) of ethyl bromoacrylate dissolved in 70 mL of tetrahydrofuran is slowly dropped while maintaining the temperature in the flask at 40 ° C. or less did. After completion of the dropwise addition, the mixture was stirred at room temperature for 30 minutes, and then the reaction was stopped by adding silica gel. After solids were removed by celite filtration, ethyl acetate was added, and the mixture was washed three times with an aqueous ammonium chloride solution. Purification by column chromatography gave a compound (M-51) represented by the following formula (yield 17.3 g, 63%).

Synthesis Examples 52 to 74 (Synthesis of Compounds (M-52) to (M-74))
The precursors were selected appropriately, and by performing the same operation as in Synthesis Example 25, the compounds (M-52) to (M-74) represented by the following formulas were synthesized.

<Synthesis of [A] Polymer and [E] Polymer>
Apart from the compound (monomer) synthesized as described above, a monomer represented by the following formula was prepared as a monomer used in the synthesis of each polymer in each example and comparative example.

Synthesis Example 75 Synthesis of Polymer (A-1)
6.33 g (30 mol%) of compound (M'-1), 6.13 g (40 mol%) of compound (M'-2), 4.26 g (20 mol%) of compound (M'-3), and the compound (M-1) 3.28 g (10 mol%) of (M-1) is dissolved in 40 g of 2-butanone, and 0.74 g (5 mol% based on all monomers) of azobisisobutyronitrile (AIBN) as a radical initiator Was added to prepare a monomer solution. Next, a 100 mL three-necked flask containing 20 g of 2-butanone was purged with nitrogen for 30 minutes, heated to 80 ° C. with stirring, and the above prepared monomer solution was added dropwise over 3 hours using a dropping funnel. The start of dropwise addition was taken as the start time of the polymerization reaction, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization reaction, the polymerization solution was cooled to 30 ° C. or less by water cooling. The cooled polymerization solution was charged into 400 g of methanol, and the precipitated white powder was separated by filtration. The filtered white powder was washed twice with 80 g of methanol, filtered, and dried at 50 ° C. for 17 hours to obtain a white powdery polymer (A-1) (yield 15.8 g, yield) 79%). Mw of polymer (A-1) was 7,400, and Mw / Mn was 1.54. As a result of ¹³ C-NMR analysis, the content ratio of each structural unit derived from the compound (M′-1), the compound (M′-2), the compound (M′-3) and the compound (M-1) is respectively It was 30.1 mol%, 40.1 mol%, 19.6 mol% and 10.2 mol%.

Synthesis Example 152 Synthesis of Polymer (A-78)
Compound (M'-4) 44.91 g (60 mol%), Compound (M'-5) 22.92 g (20 mol%), Compound (M-2) 32.17 g (20 mol%), radical initiator After dissolution of 3.79 g of AIBN (5 mol% to total monomers) and 1.14 g of t-dodecyl mercaptan (1.5 mol% to total monomers) in 100 g of propylene glycol monomethyl ether as Under a nitrogen atmosphere, the reaction temperature was kept at 70 ° C. for copolymerization for 16 hours. After completion of the polymerization reaction, the polymerization solution was dropped into 1,000 g of n-hexane to coagulate and purify the polymer. Next, 150 g of propylene glycol monomethyl ether was added again to the above polymer, and 150 g of methanol, 34 g of triethylamine and 6 g of water were further added, and a hydrolysis reaction was performed for 8 hours while refluxing at the boiling point. After completion of the reaction, the solvent and triethylamine are distilled off under reduced pressure, and the obtained polymer is dissolved in 150 g of acetone and then added dropwise to 2,000 g of water to coagulate, and the formed white powder is filtered at 50.degree. After drying for a while, a white powdery polymer (A-78) was obtained (yield 66.2 g, 76%). The Mw of the polymer (A-78) was 7,600, and the Mw / Mn was 1.91. As a result of ¹³ C-NMR analysis, the content ratio of the p-hydroxystyrene unit, the structural unit derived from the compound (M′-5), and the structural unit derived from the compound (M-2) is 60.2 mol% , 19.8 mol%, and 20.0 mol%.

Synthesis Examples 76 to 151 and 153 to 162 (Synthesis of Polymers (A-2) to (A-77) and (A-79) to (A-88))
Polymers (A-2) to (A-77) and (A-79) were prepared in the same manner as in Synthesis Example 75, except that the types and amounts of the monomers shown in Tables 1 to 5 below were used. To (A-81) and (A-83) to (A-87) were synthesized. Further, polymers (A-82) and (A-88) were synthesized in the same manner as in Synthesis Example 152 except that monomers of types and amounts shown in Table 5 below were used. In addition, "-" in Table 5 shows that the corresponding monomer was not used.

Synthesis Example 163 Synthesis of Polymer (E-1)
79.9 g (70 mol%) of the compound (M'-6) and 20.91 g (30 mol%) of the compound (M'-17) are dissolved in 100 g of 2-butanone, and dimethyl 2,2 is used as a radical initiator A monomer solution was prepared by dissolving 4.77 g of '-azobisisobutyrate. Next, a 1,000 mL three-necked flask containing 100 g of 2-butanone was purged with nitrogen for 30 minutes, heated to 80 ° C. with stirring, and the above prepared monomer solution was added dropwise over 3 hours using a dropping funnel . The start of dropwise addition was taken as the start time of the polymerization reaction, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization reaction, the polymerization solution was cooled to 30 ° C. or less by water cooling. The reaction solution was transferred to a 2 L separatory funnel, and then the polymerization solution was uniformly diluted with 150 g of n-hexane, and 600 g of methanol was added and mixed. Next, 30 g of distilled water was added, and the mixture was further stirred and allowed to stand for 30 minutes. Next, the solvent was replaced with propylene glycol monomethyl ether acetate to obtain a propylene glycol monomethyl ether acetate solution containing polymer (E-1) which is a solid content (yield 60%). Mw of polymer (E-1) was 7,200, and Mw / Mn was 2.00. As a result of ¹³ C-NMR analysis, the content ratio of each structural unit derived from the compound (M′-6) and the compound (M′-17) was 71.1 mol% and 28.9 mol%, respectively.

Preparation of Radiation-Sensitive Resin Composition (I)
[B] Acid generator, [C] solvent, [D] acid diffusion control agent and [F] uneven distribution accelerator used in preparation of the radiation sensitive resin composition (I) in the following Examples and Comparative Examples Shown in.

[[B] acid generator]
B-1: Triphenylsulfonium 2- (adamantan-1-ylcarbonyloxy) -1,1,3,3,3-pentafluoropropane-1-sulfonate B-2: norbornane sulton-2-yloxycarbonyldifluoromethane Sulfonate B-3: Triphenylsulfonium 3- (piperidin-1-ylsulfonyl) -1,1,2,2,3,3-hexafluoropropane-1-sulfonate B-4: Triphenylsulfoniumadamantan-1-yl Oxycarbonyldifluoromethanesulfonate Each structural formula is shown below.

[[C] solvent]
C-1: Propylene glycol monomethyl ether acetate C-2: Cyclohexanone

[[D] acid diffusion control agent]
D-1: Triphenylsulfonium salicylate D-2: Triphenylsulfonium 10-camphorsulfonate D-3: N- (n-undecane-1-ylcarbonyloxyethyl) morpholine D-4: 2, 6-dii -Propylaniline D-5: tri n-pentylamine Structural formula is shown below.

[[F] uneven distribution promoter]
F-1: γ-butyrolactone

Example 1
[A] 100 parts by mass of (A-1) as a polymer, 8.5 parts by mass of (B-1) as an [B] acid generator, (C-1) 2,240 parts as a [C] solvent Parts and (C-2) 960 parts by mass, (D-1) 2.3 parts by mass as the [D] acid diffusion control agent, (E-1) 3 parts by mass as the [E] polymer, and [F] The radiation sensitive resin composition of Example 1 was prepared by blending 30 parts by mass of (F-1) as an uneven distribution accelerator and filtering it through a membrane filter with a pore size of 0.2 μm.

[Examples 2 to 77 and Comparative Examples 1 to 4]
Each radiation sensitive resin composition was prepared in the same manner as in Example 1 except that each component of types and blending amounts shown in Tables 6 to 9 below was used.

<Formation of resist pattern (1)> (ArF exposure)
After a composition for formation of a lower anti-reflection film ("ARC 66" from Brewer Science, Inc.) was applied to a 12-inch silicon wafer surface using a spin coater ("CLEAN TRACK ACT 12" from Tokyo Electron), 205 ° C By heating for 60 seconds to form a lower antireflective film having an average thickness of 105 nm. Each of the radiation sensitive resin compositions prepared above was applied onto the lower antireflective film using the above-mentioned spin coater, and PB was performed at 90 ° C. for 60 seconds. Then, it cooled at 23 degreeC for 30 second, and formed the resist film with an average thickness of 90 nm. Next, using the ArF excimer laser immersion exposure apparatus ("NSR-S610C" manufactured by NIKON), this resist film is used under the optical conditions of NA = 1.3 and a dipole (sigma 0.977 / 0.782) The light was exposed through a 40 nm line and space (1L1S) mask pattern. After exposure, PEB was performed at 90 ° C. for 60 seconds. Thereafter, it was developed with an organic solvent using n-butyl acetate as a developer and dried to form a negative resist pattern. When this resist pattern is formed, the exposure amount at which the line width formed through a 1-to-1 line-and-space mask with a target size of 40 nm is formed on a 1-to-1 line-and-space with a 40 nm line width is the optimum exposure amount. did.

<Evaluation>
Each radiation sensitive resin composition was evaluated by measuring according to the following method about the formed said resist pattern. The results are shown in Tables 10 and 11 below. A scanning electron microscope ("CG-4100" manufactured by Hitachi High-Technologies Corporation) was used for measuring the resist pattern.

[LWR performance]
The resist pattern was observed from above using the scanning electron microscope. The line width was measured at a total of 50 points at arbitrary points, and a 3-sigma value was obtained from the distribution of the measured values, and this was taken as the LWR performance (nm). LWR performance shows that the smaller the value, the better. The LWR performance can be evaluated as good when it is 3.5 nm or less, and as bad when it exceeds 3.5 nm.

[Resolution]
Measure the dimensions of the smallest resist pattern that is resolved when the size of the mask pattern that forms the line and space (1L / 1S) is changed at the above optimum exposure amount, and resolve this measured value (nm) And The resolution shows that the smaller the value, the better. The resolution can be evaluated as good when it is 35 nm or less, and as poor when it exceeds 35 nm.

[Rectangularity of cross-sectional shape]
The cross-sectional shape of the resist pattern resolved at the above optimum exposure amount was observed, and the line width Lb at the central portion in the thickness direction of the resist pattern and the line width La at the top of the resist pattern were measured. Then, La / Lb was calculated, and this was used as a measure of the rectangularity of the cross-sectional shape. The rectangularity of the cross-sectional shape can be evaluated as good when 0.9 ≦ La / Lb ≦ 1.1, and as poor when it is outside the above range.

[Depth of focus]
In the resist pattern resolved at the above optimum exposure dose, the dimension (line width) when changing the focus in the depth direction is observed, and the pattern dimension is 90% or more and 110% or less of the reference without any bridge or residue. The allowance in the depth direction was measured, and this measured value was taken as the focal depth (nm). The depth of focus indicates that the larger the value, the better. The depth of focus can be evaluated as good if it is 50 nm or more and bad if it is less than 50 nm.

[Resist film shrinkage suppression property]
After a composition for formation of a lower anti-reflection film ("ARC 66" from Brewer Science, Inc.) was applied to a 12-inch silicon wafer surface using a spin coater ("CLEAN TRACK ACT 12" from Tokyo Electron), 205 ° C By heating for 60 seconds to form a lower antireflective film having an average thickness of 105 nm. Each of the radiation sensitive resin compositions prepared above was applied onto the lower antireflective film using the above-mentioned spin coater, and PB was performed at 90 ° C. for 60 seconds. Then, it cooled at 23 degreeC for 30 second, and formed the resist film with an average thickness of 90 nm. Next, the resist film was exposed on the entire surface at 70 mJ / cm ² using an ArF excimer laser immersion exposure apparatus (“NSR-S610C” manufactured by NIKON), and film thickness measurement was carried out. nm) was determined. Subsequently, after performing PEB at 90 ° C. for 60 seconds, film thickness measurement was performed again to determine an average thickness B (nm). From the measured values of the average thicknesses A and B, 100 × (A−B) / A was calculated, and this was taken as the resist film shrinkage inhibitory property (%). The results are shown in Tables 10 and 11 below. The resist film shrinkage suppression property indicates that the smaller the value, the better. The resist film shrinkage inhibitory property can be evaluated as good when it is 20% or less and as defective when it exceeds 20%.

[Example 78]
[A] 100 parts by mass of (A-1) as a polymer, 20 parts by mass of (B-1) as a [B] acid generator, (280) parts by mass of (C-1) as a [C] solvent, Example 78 was prepared by blending 1,830 parts by mass of (C-2) and 3.6 parts by mass of (D-1) as the acid diffusion control agent [D] and filtering it through a membrane filter with a pore size of 0.2 μm. A radiation sensitive resin composition was prepared.

[Examples 79 to 87 and Comparative Examples 5 to 9]
Each radiation sensitive resin composition was prepared in the same manner as in Example 78 except that each component of the type and the blending amount shown in Table 12 below was used. In addition, "-" in Table 12 shows that the applicable component was not used.

<Formation of resist pattern (2)> (electron beam exposure)
Each radiation sensitive resin composition described in the following Table 12 is applied to an 8-inch silicon wafer surface using a spin coater (“CLEAN TRACK ACT 8” of Tokyo Electron Ltd.), and PB is performed at 90 ° C. for 60 seconds. The Then, it cooled at 23 degreeC for 30 second, and formed the resist film with an average thickness of 50 nm. Next, the resist film was irradiated with an electron beam using a simple type electron beam lithography system (“HL800D” manufactured by Hitachi, Ltd., output: 50 KeV, current density: 5.0 A / cm ² ). After irradiation, PEB was performed at 120 ° C. for 60 seconds. Thereafter, it was developed with an organic solvent using n-butyl acetate as a developer and dried to form a negative resist pattern.

<Evaluation>
The resist patterns formed using the above radiation sensitive resin compositions were evaluated in the same manner as in the case of the above ArF exposure. The results are shown in Table 12 below. In the case of electron beam exposure, the LWR performance can be evaluated as good if it is 5.0 nm or less, and poor if it exceeds 5.0 nm, and good if it has a resolution of 33 nm or less, it is bad as over 33 nm. It can be evaluated, the rectangularity of the cross-sectional shape can be evaluated as good in the case of 0.9 ≦ La / Lb ≦ 1.1 and poor in the other range, and good in the case of 50 nm or more and less than 50 nm The case can be evaluated as bad.

  As can be seen from the results in Tables 10 to 12, the radiation sensitive resin compositions of the examples exhibited LWR performance, resolution, rectangularity in cross-sectional shape, and depth of focus in both cases of ArF exposure and electron beam exposure. And excellent in resist film shrinkage suppression. On the other hand, the radiation sensitive resin composition of the comparative example was inferior in these performances to the thing of the Example in any case. In addition, it is known that electron beam exposure generally exhibits the same tendency as in the case of EUV exposure, and accordingly, in the case of EUV exposure, according to the radiation sensitive resin composition of the embodiment, It is estimated that the LWR performance etc. is excellent.

  According to the resist pattern forming method and the radiation sensitive resin composition of the present invention, it is possible to suppress the shrinkage of the resist film at the time of PEB while enhancing the optical contrast by using the developing solution containing the organic solvent, and LWR Etc. can be improved.

Claims (8)

Forming a resist film with a radiation sensitive resin composition,
A method of forming a resist pattern comprising: exposing the resist film; and developing the exposed resist film with a developer containing an organic solvent.
The above-mentioned radiation sensitive resin composition contains a polymer, a radiation sensitive acid generator and a solvent in which the solubility in the above developer decreases by the action of an acid,
The polymer has a structural unit containing a first group,
The first group is a first acid dissociable group,
A method of forming a resist pattern, wherein the first group is represented by the following formula (2-1), the following formula (2-2) or the following formula (3) .

(In formula (2-1), R ² is a monovalent organic group having 1 to 20 carbon atoms. R ³ is a cyanomethyl group, a hydroxyethyl group, a monovalent chain organic having 3 to 20 carbon atoms Group, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms substituted with a cyano group or a hydroxy group, 1 having 3 to 20 carbon atoms A monovalent hydrocarbon group of 1 to 20 carbon atoms substituted with a divalent aliphatic heterocyclic group or a monovalent aliphatic heterocyclic group of 3 to 20 carbon atoms, p 1 is an integer of 1 to 14 When p1 is 2 or more, a plurality of R ^{3 s} may be the same or different, and two or more of a plurality of —OR ³ are combined with each other and the carbon atom or carbon chain to which they are bonded has 3 ring members optionally form a ring structure to 20 .R ⁴ is a monovalent organic group or the carbon atoms other than -OR ³ 1 to 20 = Is O .P2 the case of .P2 2 or more is an integer of 0 to 13, a plurality of R ⁴ may be the same or different, two or more of the plurality of R ⁴ are combined with each other They may form a ring structure having 3 to 20 ring members together with a carbon atom or a carbon chain to which they are attached, provided that p1 + p2 is 14 or less. It shows the site (except when a ^{group R 3} is represented by -C (= O) -O-C (CH 3) 3.).)

(In formula (2-2), R ⁵ and R ⁶ are each independently a monovalent organic group having 1 to 20 carbon atoms, or these groups are combined with each other and together with the carbon atom to which they are bonded] R ⁷ and R ⁸ each independently represent a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, and q 1 is a group of 0 to 20. When q1 is 2 or more, a plurality of R ⁷ may be the same or different, and a plurality of R ⁸ may be the same or different 1 or more R ⁷ and one or more two or more of R ⁸ is optionally .R ⁹ to form a ring structure of ring members 3 to 20, together with keyed these groups with each other carbon atom or carbon chain they are attached, a cyanomethyl group, Hydroxyethyl group, monovalent linear organic group having 3 to 20 carbon atoms, 3 to 3 carbon atoms A monovalent alicyclic hydrocarbon group of 0, a monovalent alicyclic hydrocarbon group of 3 to 20 carbon atoms substituted with a cyano group or a hydroxy group, a monovalent aliphatic heterocyclic ring of 3 to 20 carbon atoms It is a C1-C20 monovalent hydrocarbon group substituted by the group or C3-C20 monovalent aliphatic heterocyclic group q2 is an integer of 1-15 q2 is 2 or more In the case of a plurality of R ⁹ may be the same or different, and two or more of a plurality of -OR ⁹ are combined with each other and together with the carbon atom or carbon chain to which they are attached R ¹⁰ is a monovalent organic group having 1 to 20 carbon atoms other than —OR ⁹ or OO, q 3 is an integer of 0 to 14. q 3 is 2 or more , the plurality of R ¹⁰ may be the same or different, combined two or more of the plurality of R ¹⁰ are mutually Or a carbon atom to which they are attached or a carbon chain may form a ring structure having 3 to 20 ring members, provided that q 2 + q 3 is 15 or less. * Is a moiety other than the first group of the structural unit Indicates the binding site.)

(In formula (3), R ¹¹ and R ¹² are each independently a monovalent organic group having 1 to 20 carbon atoms. R ¹³ is a monovalent organic group having 1 to 20 carbon atoms or OO R is an integer of 0 to 15. When r is 2 or more, a plurality of R ¹³ may be the same or different, and 2 or more of a plurality of R ¹³ may be combined with one another. It may form a ring structure having 3 to 20 ring members together with the carbon atom or carbon chain to be bound.L ¹ is a single bond or a divalent organic group having 1 to 20 carbon atoms, R ¹¹ and R ¹² And two or more of L ¹ may be combined with each other to form a ring structure of 3 to 20 ring members with a carbon atom to which they are bonded. * Represents a moiety other than the first group of the above structural units Indicates the binding site.) The method for forming a resist pattern according to claim 1 , wherein R ³ and R ⁹ contain a second acid dissociable group. Forming a resist film with a radiation sensitive resin composition,
Exposing the resist film, and
Developing the exposed resist film with a developer containing an organic solvent
A resist pattern forming method comprising
The above-mentioned radiation sensitive resin composition contains a polymer, a radiation sensitive acid generator and a solvent in which the solubility in the above developer decreases by the action of an acid,
The polymer has a structural unit containing a first group,
A method of forming a resist pattern, wherein the first group is represented by the following formula (4-1) or the following formula (4-2) .

(In formula (4-1), R ¹⁴ and R ¹⁵ each independently represent a hydrogen atom, a fluorine atom, a hydroxy group or a monovalent organic group having 1 to 20 carbon atoms. S1 is 0 to 5) When s1 is 2 or more, a plurality of R ¹⁴ may be the same or different, and a plurality of R ¹⁵ may be the same or different 1 or more R ¹⁴ and one or more R ¹⁵ two or more of, good .R ¹⁶ to form a ring structure of ring members 3 to 20, together with keyed these groups together carbon atoms or a carbon chain which they are attached, having from 1 to 20 carbon atoms S2 is an integer of 1 to 14. When s2 is 2 or more, a plurality of R ¹⁶ may be the same or different, and two of a plurality of -OR ¹⁶ The above are combined together with the carbon atom or carbon chain to which they are attached Good ^.R 17 also form a ring structure membered 3-20 is a monovalent organic group or = O at carbon atoms other than ^{-OR 16 1~20 .s3} is an integer of 0 to 13 If there .s3 is 2 or more, plural R ¹⁷ may be the same or different, ring members 3 together with the carbon atom or carbon chain two or more of the plurality of R ¹⁷ are combined they are bound to each other It may form a ring structure of 20. However, s 2 + s 3 is 14 or less * 1 represents a site to be bonded to a moiety other than the first group of the structural unit * 2 represents the structural unit Indicates a site binding to an adjacent structural unit.)

(In formula (4-2), R ¹⁸ and R ¹⁹ each independently represent a hydrogen atom, a fluorine atom, a hydroxy group or a monovalent organic group having 1 to 20 carbon atoms. T1 is 0 to 5) When t1 is 2 or more, a plurality of R ¹⁸ may be the same or different, and a plurality of R ¹⁹ may be the same or different 1 or more R ¹⁸ and one or more R ¹⁹ two or more of, good .R ²⁰ to form a ring structure of ring members 3 to 20, together with keyed these groups together carbon atoms or a carbon chain which they are attached, having from 1 to 20 carbon atoms L ² is a single bond or a divalent organic group having 1 to ²⁰ carbon atoms, and R ²⁰ and L ² are combined with each other, and together with the carbon atom to which they are bonded, 3 to 3 ring members. optionally form a ring structure of 20 ^{.R 21} is 1 to carbon atoms 0 is a monovalent organic group .t2 the case of .t2 2 or more is an integer of 1 to 14, a plurality of ^{R 21} may be the same or different, two of the plurality of ^{-OR 21} One or more may be combined with each other to form a ring structure having 3 to 20 ring members with a carbon atom or a carbon chain to which they are attached. R ²² is a monovalent having 1 to 20 carbon atoms other than -OR ²¹ . organic group or a = a O .T3 the case of .T3 2 or more is an integer of 0 to 13, a plurality of ^{R 22} may be the same or different, two or more of the plurality of ^{R 22} is They may be combined with each other to form a ring structure having 3 to 20 ring members together with carbon atoms or carbon chains to which they are bonded, provided that t2 + t3 is 14 or less. * 1 is other than the first group of the structural units Indicates a site binding to the moiety of * .2 is adjacent to the above structural unit Indicates the site bound to the adjacent structural unit.) The method for forming a resist pattern according to claim 3 , wherein each of R ¹⁶ and R ²¹ contains a third acid dissociable group. A polymer whose solubility in a developer containing an organic solvent is reduced by the action of an acid,
A radiation sensitive resin composition comprising a radiation sensitive acid generator and a solvent,
The above polymer is characterized by having a structural unit including a first acid dissociable group represented by the following formula (2-1), the following formula (2-2) or the following formula (3). Resin composition.

(In formula (2-1), R ² is a monovalent organic group having 1 to 20 carbon atoms. R ³ is a cyanomethyl group, a hydroxyethyl group, a monovalent chain organic having 3 to 20 carbon atoms Group, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms substituted with a cyano group or a hydroxy group, 1 having 3 to 20 carbon atoms A monovalent hydrocarbon group of 1 to 20 carbon atoms substituted with a divalent aliphatic heterocyclic group or a monovalent aliphatic heterocyclic group of 3 to 20 carbon atoms, p 1 is an integer of 1 to 14 When p1 is 2 or more, a plurality of R ^{3 s} may be the same or different, and two or more of a plurality of —OR ³ are combined with each other and the carbon atom or carbon chain to which they are bonded has 3 ring members optionally form a ring structure to 20 .R ⁴ is a monovalent organic group or the carbon atoms other than -OR ³ 1 to 20 = Is O .P2 the case of .P2 2 or more is an integer of 0 to 13, a plurality of R ⁴ may be the same or different, two or more of the plurality of R ⁴ are combined with each other They may form a ring structure having 3 to 20 ring members together with a carbon atom or a carbon chain to which they are attached, provided that p1 + p2 is 14 or less. * Is a bond to a moiety other than the first group of the structural unit It shows the site (except when a ^{group R 3} is represented by -C (= O) -O-C (CH 3) 3.).)

(In formula (2-2), R ⁵ and R ⁶ are each independently a monovalent organic group having 1 to 20 carbon atoms, or these groups are combined with each other and together with the carbon atom to which they are bonded] R ⁷ and R ⁸ each independently represent a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, and q 1 is a group of 0 to 20. When q1 is 2 or more, a plurality of R ⁷ may be the same or different, and a plurality of R ⁸ may be the same or different 1 or more R ⁷ and one or more two or more of R ⁸ is optionally .R ⁹ to form a ring structure of ring members 3 to 20, together with keyed these groups with each other carbon atom or carbon chain they are attached, a cyanomethyl group, Hydroxyethyl group, monovalent linear organic group having 3 to 20 carbon atoms, 3 to 3 carbon atoms A monovalent alicyclic hydrocarbon group of 0, a monovalent alicyclic hydrocarbon group of 3 to 20 carbon atoms substituted with a cyano group or a hydroxy group, a monovalent aliphatic heterocyclic ring of 3 to 20 carbon atoms It is a C1-C20 monovalent hydrocarbon group substituted by the group or C3-C20 monovalent aliphatic heterocyclic group q2 is an integer of 1-15 q2 is 2 or more In the case of a plurality of R ⁹ may be the same or different, and two or more of a plurality of -OR ⁹ are combined with each other and together with the carbon atom or carbon chain to which they are attached R ¹⁰ is a monovalent organic group having 1 to 20 carbon atoms other than —OR ⁹ or OO, q 3 is an integer of 0 to 14. q 3 is 2 or more , the plurality of R ¹⁰ may be the same or different, combined two or more of the plurality of R ¹⁰ are mutually Or a carbon atom to which they are attached or a carbon chain may form a ring structure having 3 to 20 ring members, provided that q 2 + q 3 is 15 or less. * Is a moiety other than the first group of the structural unit Indicates a site to be bound (except in the case where R ⁹ is a group represented by -CH ₂ OCH ₂ CH ₃ ) .

(In formula (3), R ¹¹ and R ¹² are each independently a monovalent organic group having 1 to 20 carbon atoms. R ¹³ is a monovalent organic group having 1 to 20 carbon atoms or OO R is an integer of 0 to 15. When r is 2 or more, a plurality of R ¹³ may be the same or different, and 2 or more of a plurality of R ¹³ may be combined with one another. It may form a ring structure having 3 to 20 ring members together with the carbon atom or carbon chain to be bound.L ¹ is a single bond or a divalent organic group having 1 to 20 carbon atoms, R ¹¹ and R ¹² And two or more of L ¹ may be combined with each other to form a ring structure of 3 to 20 ring members with a carbon atom to which they are bonded. * Represents a moiety other than the first group of the above structural units Indicates the binding site.) The radiation sensitive resin composition according to claim 5 , wherein R ³ and R ⁹ contain a second acid dissociable group. A polymer whose solubility in a developer containing an organic solvent is reduced by the action of an acid,
A radiation sensitive resin composition comprising a radiation sensitive acid generator and a solvent,
The radiation sensitive resin composition characterized by the said polymer having a structural unit containing 1st group represented by following formula (4-1) or following formula (4-2).

(In formula (4-1), R ¹⁴ and R ¹⁵ each independently represent a hydrogen atom, a fluorine atom, a hydroxy group or a monovalent organic group having 1 to 20 carbon atoms. S1 is 0 to 5) When s1 is 2 or more, a plurality of R ¹⁴ may be the same or different, and a plurality of R ¹⁵ may be the same or different 1 or more R ¹⁴ and one or more R ¹⁵ two or more of, good .R ¹⁶ to form a ring structure of ring members 3 to 20, together with keyed these groups together carbon atoms or a carbon chain which they are attached, having from 1 to 20 carbon atoms S2 is an integer of 1 to 14. When s2 is 2 or more, a plurality of R ¹⁶ may be the same or different, and two of a plurality of -OR ¹⁶ The above are combined together with the carbon atom or carbon chain to which they are attached Good ^.R 17 also form a ring structure membered 3-20 is a monovalent organic group or = O at carbon atoms other than ^{-OR 16 1~20 .s3} is an integer of 0 to 13 If there .s3 is 2 or more, plural R ¹⁷ may be the same or different, ring members 3 together with the carbon atom or carbon chain two or more of the plurality of R ¹⁷ are combined they are bound to each other It may form a ring structure of 20. However, s 2 + s 3 is 14 or less * 1 represents a site to be bonded to a moiety other than the first group of the structural unit * 2 represents the structural unit Indicates a site to be bound to an adjacent structural unit (except in the case where R ¹⁶ is a group represented by -C (= O) -CF ₃ ) .

(In formula (4-2), R ¹⁸ and R ¹⁹ each independently represent a hydrogen atom, a fluorine atom, a hydroxy group or a monovalent organic group having 1 to 20 carbon atoms. T1 is 0 to 5) When t1 is 2 or more, a plurality of R ¹⁸ may be the same or different, and a plurality of R ¹⁹ may be the same or different 1 or more R ¹⁸ and one or more R ¹⁹ two or more of, good .R ²⁰ to form a ring structure of ring members 3 to 20, together with keyed these groups together carbon atoms or a carbon chain which they are attached, having from 1 to 20 carbon atoms L ² is a single bond or a divalent organic group having 1 to ²⁰ carbon atoms, and R ²⁰ and L ² are combined with each other, and together with the carbon atom to which they are bonded, 3 to 3 ring members. optionally form a ring structure of 20 ^{.R 21} is 1 to carbon atoms 0 is a monovalent organic group .t2 the case of .t2 2 or more is an integer of 1 to 14, a plurality of ^{R 21} may be the same or different, two of the plurality of ^{-OR 21} One or more may be combined with each other to form a ring structure having 3 to 20 ring members with a carbon atom or a carbon chain to which they are attached. R ²² is a monovalent having 1 to 20 carbon atoms other than -OR ²¹ . organic group or a = a O .T3 the case of .T3 2 or more is an integer of 0 to 13, a plurality of ^{R 22} may be the same or different, two or more of the plurality of ^{R 22} is They may be combined with each other to form a ring structure having 3 to 20 ring members together with carbon atoms or carbon chains to which they are bonded, provided that t2 + t3 is 14 or less. * 1 is other than the first group of the structural units Indicates a site binding to the moiety of * .2 is adjacent to the above structural unit Indicates the site bound to the adjacent structural unit.) The radiation sensitive resin composition according to claim 7 , wherein each of R ¹⁶ and R ²¹ contains a third acid dissociable group.