JP6866866B2 - Resist material and pattern formation method - Google Patents

Description

The present invention relates to a resist material containing a polymer containing a repeating unit having iodine and an acid generator containing a sulfonium salt or an iodonium salt of fluorosulfonic acid having iodine, and a pattern forming method using the same.

With the increasing integration and speed of LSIs, the miniaturization of pattern rules is rapidly progressing. In particular, logic devices used in smartphones and the like are driving miniaturization, and 10 nm node logic devices are mass-produced using a multiple exposure (multi-patterning lithography) process by ArF lithography.

In the next 7 nm node and 5 nm node lithography, the high cost due to multiple exposures and the problem of overlay accuracy in multiple exposures have become apparent, and the arrival of extreme ultraviolet (EUV) lithography that can reduce the number of exposures is expected. Has been done.

EUV with a wavelength of 13.5 nm has a shorter wavelength of 1/10 or less than ArF lithography with a wavelength of 193 nm, so that light contrast is high and high resolution is expected. Since EUV has a short wavelength and a high energy density, the acid generator is exposed to a small amount of photons. The number of photons in EUV exposure is said to be 1/14 of ArF exposure. In EUV exposure, the phenomenon that the edge roughness (LWR) of lines and the dimensional uniformity (CDU) of holes are deteriorated due to the variation of photons is regarded as a problem.

In order to reduce the variation of photons, it has been proposed to increase the absorption of the resist and increase the number of photons absorbed in the resist.

Styrene-based resins substituted with halogen atoms have been studied for some time (Patent Document 1). In particular, among halogen atoms, iodine atoms have high absorption in EUV light having a wavelength of 13.5 nm. Therefore, in recent years, it has been proposed to use a resin having iodine atoms as an EUV resist material (Patent Documents 2 and 3). However, it is not the case that the number of photons absorbed increases and the sensitivity becomes high if iodine atoms are contained. In terms of acid generation efficiency in EUV exposure, styrene iodide is only 14% of hydroxystyrene (non-patented). It is reported as Document 1).

Japanese Unexamined Patent Publication No. 5-204157 Japanese Unexamined Patent Publication No. 2015-161823 International Publication No. 2013/024777

Jpn. J. Appl. Physics Vol. 46, No. 7, pp. L142-L144, 2007

In an acid-catalyzed chemically amplified resist, it is desired to develop a resist material having high sensitivity and capable of reducing LWR and hole pattern CDU.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a resist material having high sensitivity and a small LWR and CDU, and a pattern forming method using the same, regardless of whether it is a positive resist material or a negative resist material. To do.

As a result of diligent studies to achieve the above object, the present inventors have made a resist containing a polymer containing an iodine atom and an acid generator containing a sulfonium salt and / or an iodonium salt of an iodinated benzene ring-containing fluorosulfonic acid. The present invention has been completed by finding that the material is a resist material having high sensitivity, small LWR and CDU, and a wide process margin.

（式中、Ｌ¹は、単結合、エーテル結合若しくはエステル結合、又はエーテル結合若しくはエステル結合を含んでいてもよい炭素数１〜６のアルキレン基である。
Ｒ¹は、ヒドロキシ基、カルボキシ基、フッ素原子、塩素原子、臭素原子若しくはアミノ基、若しくはフッ素原子、塩素原子、臭素原子、ヒドロキシ基、アミノ基若しくは炭素数１〜１０のアルコキシ基を含んでいてもよい、炭素数１〜２０のアルキル基、炭素数１〜２０のアルコキシ基、炭素数２〜１０のアルコキシカルボニル基、炭素数２〜２０のアシロキシ基若しくは炭素数１〜２０のアルキルスルホニルオキシ基、又は−ＮＲ⁸−Ｃ(＝Ｏ)−Ｒ⁹若しくは−ＮＲ⁸−Ｃ(＝Ｏ)−Ｏ−Ｒ⁹であり、Ｒ⁸は、水素原子、又はハロゲン原子、ヒドロキシ基、炭素数１〜６のアルコキシ基、炭素数２〜６のアシル基若しくは炭素数２〜６のアシロキシ基を含んでいてもよい炭素数１〜６のアルキル基であり、Ｒ⁹は、炭素数１〜１６のアルキル基、炭素数２〜１６のアルケニル基、又は炭素数６〜１２のアリール基であり、ハロゲン原子、ヒドロキシ基、炭素数１〜６のアルコキシ基、炭素数２〜６のアシル基、又は炭素数２〜６のアシロキシ基を含んでいてもよい。
Ｒ²は、ｐが１のときは単結合又は炭素数１〜２０の２価の連結基であり、ｐが２又は３のときは炭素数１〜２０の３価又は４価の連結基であり、該連結基は酸素原子、硫黄原子又は窒素原子を含んでいてもよい。
Ｒｆ¹〜Ｒｆ⁴は、それぞれ独立に、水素原子、フッ素原子又はトリフルオロメチル基であるが、これらのうち少なくとも１つはフッ素原子又はトリフルオロメチル基である。また、Ｒｆ¹とＲｆ²とが合わさって、カルボニル基を形成してもよい。
Ｒ³、Ｒ⁴、Ｒ⁵、Ｒ⁶及びＲ⁷は、それぞれ独立に、ヘテロ原子を含んでいてもよい炭素数１〜２０の１価炭化水素基である。また、Ｒ³、Ｒ⁴及びＲ⁵のいずれか２つが、互いに結合してこれらが結合する硫黄原子と共に環を形成してもよい。
ｐは、１≦ｐ≦３を満たす整数である。ｑ及びｒは、１≦ｑ≦５、０≦ｒ≦３、及び１≦ｑ＋ｒ≦５を満たす整数である。）
３．前記ヨウ素原子を含むポリマーが、下記式（ａ１）又は（ａ２）で表される繰り返し単位を含むものである１又は２のレジスト材料。

（式中、Ｒ^Aは、それぞれ独立に、水素原子又はメチル基である。Ｒ²¹は、単結合又はメチレン基である。Ｒ²²は、水素原子、又は炭素数１〜４のアルキル基である。Ｘ¹は、単結合、エーテル結合、エステル結合、アミド結合、−Ｃ(＝Ｏ)−Ｏ−Ｒ²³−、フェニレン基、−Ｐｈ−Ｃ(＝Ｏ)−Ｏ−Ｒ²⁴−）、又は−Ｐｈ−Ｒ²⁵−Ｏ−Ｃ(＝Ｏ)−Ｒ²⁶−であり、Ｐｈはフェニレン基である。Ｒ²³は、炭素数１〜１０のアルキレン基であり、エーテル結合又はエステル結合を含んでいてもよい。Ｒ²⁴、Ｒ²⁵及びＲ²⁶は、それぞれ独立に、単結合、又は直鎖状若しくは分岐状の炭素数１〜６のアルキレン基である。ｍ及びｎは、１≦ｍ≦５、０≦ｎ≦４、及び１≦ｍ＋ｎ≦５を満たす整数である。）
４．ｎが、１〜３の整数である３のレジスト材料。
５．更に、有機溶剤を含む１〜４のいずれかのレジスト材料。
６．前記ヨウ素原子を含むポリマーが、更に下記式（ｂ１）で表される繰り返し単位又は下記式（ｂ２）で表される繰り返し単位を含むものである１〜５のいずれかのレジスト材料。

（式中、Ｒ^Aは、それぞれ独立に、水素原子又はメチル基である。Ｙ¹は、単結合、フェニレン基若しくはナフチレン基、又はエステル結合若しくはラクトン環を含む炭素数１〜１２の連結基である。Ｙ²は、単結合又はエステル結合である。Ｒ³¹及びＲ³²は、それぞれ独立に、酸不安定基である。Ｒ³³は、フッ素原子、トリフルオロメチル基、シアノ基、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、炭素数２〜７のアシル基、炭素数２〜７のアシロキシ基、又は炭素数２〜７のアルコキシカルボニル基である。Ｒ³⁴は、単結合、又は炭素数１〜６のアルキレン基であり、その炭素原子の一部が、エーテル結合又はエステル結合で置換されていてもよい。ｔは１又は２、ｓは０〜４の整数であるが、１≦ｔ＋ｓ≦５である。）
７．更に、溶解阻止剤を含む６のレジスト材料。
８．化学増幅ポジ型レジスト材料である６又は７のレジスト材料。
９．前記ヨウ素原子を含むポリマーが、酸不安定基を含まないものである１〜４のいずれかのレジスト材料。
１０．更に、架橋剤を含む９のレジスト材料。
１１．化学増幅ネガ型レジスト材料である９又は１０のレジスト材料。
１２．更に、クエンチャーを含む１〜１１のいずれかのレジスト材料。
１３．更に、界面活性剤を含む１〜１２のいずれかのレジスト材料。
１４．前記ヨウ素原子を含むポリマーが、更に、下記式（ｇ１）〜（ｇ３）で表される繰り返し単位から選ばれる少なくとも１種を含む１〜１３のいずれかのレジスト材料。

（式中、Ｒ^Aは、それぞれ独立に、水素原子又はメチル基である。
Ｚ¹は、単結合、フェニレン基、−Ｏ−Ｚ¹²−、又は−Ｃ(＝Ｏ)−Ｚ¹¹−Ｚ¹²−であり、Ｚ¹¹は、−Ｏ−又は−ＮＨ−であり、Ｚ¹²は、炭素数１〜６のアルキレン基若しくは炭素数２〜６のアルケニレン基、又はフェニレン基であり、カルボニル基、エステル結合、エーテル結合又はヒドロキシ基を含んでいてもよい。
Ｚ²は、単結合、−Ｚ²¹−Ｃ(＝Ｏ)−Ｏ−、−Ｚ²¹−Ｏ−又は−Ｚ²¹−Ｏ−Ｃ(＝Ｏ)−であり、Ｚ²¹は、炭素数１〜１２のアルキレン基であり、カルボニル基、エステル結合又はエーテル結合を含んでいてもよい。
Ａは、水素原子又はトリフルオロメチル基である。
Ｚ³は、単結合、メチレン基、エチレン基、フェニレン基、フッ素化フェニレン基、−Ｏ−Ｚ³²−又は−Ｃ(＝Ｏ)−Ｚ³¹−Ｚ³²−であり、Ｚ³¹は、−Ｏ−又は−ＮＨ−であり、Ｚ³²は、炭素数１〜６のアルキレン基、フェニレン基、フッ素化フェニレン基、トリフルオロメチル基で置換されたフェニレン基、又は炭素数２〜６のアルケニレン基であり、カルボニル基、エステル結合、エーテル結合又はヒドロキシ基を含んでいてもよい。
Ｒ⁴¹〜Ｒ⁴⁸は、それぞれ独立に、ヘテロ原子を含んでいてもよい炭素数１〜２０の１価炭化水素基である。また、Ｒ⁴³、Ｒ⁴⁴及びＲ⁴⁵のいずれか２つが、又はＲ⁴⁶、Ｒ⁴⁷及びＲ⁴⁸のいずれか２つが、互いに結合してこれらが結合する硫黄原子と共に環を形成してもよい。
Ｑ^-は、非求核性対向イオンを表す。）
１５．１〜１４のいずれかのレジスト材料を基板上に塗布し、加熱処理をしてレジスト膜を形成する工程と、前記レジスト膜を高エネルギー線で露光する工程と、現像液を用いて露光したレジスト膜を現像する工程とを含むパターン形成方法。
１６．前記高エネルギー線が、波長１９３ｎｍのＡｒＦエキシマレーザー又は波長２４８ｎｍのＫｒＦエキシマレーザーである１５のパターン形成方法。
１７．前記高エネルギー線が、電子線又は波長３〜１５ｎｍの極端紫外線である１５のパターン形成方法。 Therefore, the present invention provides the following resist materials and pattern forming methods.
1. 1. A resist material containing a base polymer containing a polymer containing an iodine atom and an acid generator containing a sulfonium salt and / or an iodonium salt of an iodinated benzene ring-containing fluorosulfonic acid.
2. The resist of 1 in which the sulfonium salt and the iodonium salt of the iodinated benzene ring-containing fluorosulfonic acid are the sulfonium salt represented by the following formula (A-1) and the iodonium salt represented by the following formula (A-2), respectively. material.

(In the formula, L ¹ is an alkylene group having 1 to 6 carbon atoms which may contain a single bond, an ether bond or an ester bond, or an ether bond or an ester bond.
R ¹ contains a hydroxy group, a carboxy group, a fluorine atom, a chlorine atom, a bromine atom or an amino group, or a fluorine atom, a chlorine atom, a bromine atom, a hydroxy group, an amino group or an alkoxy group having 1 to 10 carbon atoms. May be an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxycarbonyl group having 2 to 10 carbon atoms, an acyloxy group having 2 to 20 carbon atoms, or an alkylsulfonyloxy group having 1 to 20 carbon atoms. , Or -NR ^8- C (= O) -R ⁹ or -NR ^8- C (= O) -O-R ⁹ , where R ⁸ is a hydrogen atom or halogen atom, hydroxy group, 1 to 1 carbon atoms. An alkyl group having 1 to 6 carbon atoms which may contain an alkoxy group of 6 and an acyl group having 2 to 6 carbon atoms or an acyloxy group having 2 to 6 carbon atoms, and R ⁹ is an alkyl having 1 to 16 carbon atoms. A group, an alkenyl group having 2 to 16 carbon atoms, or an aryl group having 6 to 12 carbon atoms, which is a halogen atom, a hydroxy group, an alkoxy group having 1 to 6 carbon atoms, an acyl group having 2 to 6 carbon atoms, or a carbon number of carbon atoms. It may contain 2 to 6 acyloxy groups.
R ² is a single bond or a divalent linking group having 1 to 20 carbon atoms when p is 1, and a trivalent or tetravalent linking group having 1 to 20 carbon atoms when p is 2 or 3. Yes, the linking group may contain an oxygen atom, a sulfur atom or a nitrogen atom.
Rf ^{1 to Rf 4} are independently hydrogen atoms, fluorine atoms or trifluoromethyl groups, but at least one of them is a fluorine atom or trifluoromethyl group. Further, Rf ¹ and Rf ² may be combined to form a carbonyl group.
R ³ , R ⁴ , R ⁵ , R ⁶ and R ⁷ are monovalent hydrocarbon groups having 1 to 20 carbon atoms, which may independently contain heteroatoms. Further, ^{any two of R 3} , R ⁴ and R ⁵ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.
p is an integer that satisfies 1 ≦ p ≦ 3. q and r are integers that satisfy 1 ≦ q ≦ 5, 0 ≦ r ≦ 3, and 1 ≦ q + r ≦ 5. )
3. 3. The resist material of 1 or 2 in which the polymer containing an iodine atom contains a repeating unit represented by the following formula (a1) or (a2).

(In the formula, ^RA is a hydrogen atom or a methyl group independently. R ²¹ is a single bond or a methylene group. R ²² is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. .X ¹ represents a single bond, an ether bond, an ester bond, an amide bond, -C (= O) -O- R 23 -, a phenylene group, -Ph-C (= O) -O-R 24 -), or ^{-Ph-R 25 -O-C (} = O) -R 26 - is it, Ph is a phenylene group. R ²³ is an alkylene group having 1 to 10 carbon atoms and may contain an ether bond or an ester bond. R ²⁴ , R ²⁵ and R ²⁶ are independently single-bonded or linear or branched alkylene groups having 1 to 6 carbon atoms. m and n are integers that satisfy 1 ≦ m ≦ 5, 0 ≦ n ≦ 4, and 1 ≦ m + n ≦ 5. )
4. A resist material of 3 in which n is an integer of 1 to 3.
5. Further, any of 1 to 4 resist materials containing an organic solvent.
6. The resist material according to any one of 1 to 5, wherein the polymer containing an iodine atom further contains a repeating unit represented by the following formula (b1) or a repeating unit represented by the following formula (b2).

(In the formula, ^RA is independently a hydrogen atom or a methyl group. Y ¹ is a single bond, a phenylene group or a naphthylene group, or a linking group having 1 to 12 carbon atoms including an ester bond or a lactone ring. Y ² is a single bond or an ester bond. R ³¹ and R ³² are independently acid unstable groups. R ³³ is a hydrogen atom, a trifluoromethyl group, a cyano group, and 1 carbon number. ^{R 34} is an alkyl group of ~ 6, an alkoxy group having 1 to 6 carbon atoms, an acyl group having 2 to 7 carbon atoms, an acyloxy group having 2 to 7 carbon atoms, or an alkoxycarbonyl group having 2 to 7 carbon atoms. It is a single bond or an alkylene group having 1 to 6 carbon atoms, and a part of its carbon atom may be substituted with an ether bond or an ester bond. T is 1 or 2 and s is an integer of 0 to 4. There is, but 1 ≦ t + s ≦ 5.)
7. Further, 6 resist materials containing a dissolution inhibitor.
8. 6 or 7 resist material which is a chemically amplified positive resist material.
9. The resist material according to any one of 1 to 4, wherein the polymer containing an iodine atom does not contain an acid unstable group.
10. Further, 9 resist materials containing a cross-linking agent.
11. A resist material of 9 or 10 which is a chemically amplified negative resist material.
12. Further, any resist material of 1 to 11 containing a quencher.
13. Further, any of the resist materials 1 to 12 containing a surfactant.
14. The resist material according to any one of 1 to 13, wherein the polymer containing an iodine atom further contains at least one selected from the repeating units represented by the following formulas (g1) to (g3).

(In the formula, ^RA is a hydrogen atom or a methyl group, respectively.
Z ¹ is a single bond, a phenylene group, -O-Z ¹² -, or ^{-C (= O) -Z 11 -Z} 12 - a and, Z ¹¹ is -O- or -NH-, Z ¹² Is an alkylene group having 1 to 6 carbon atoms, an alkenylene group having 2 to 6 carbon atoms, or a phenylene group, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group.
Z ² is a single ^{bond, -Z 21 -C (= O)} -O -, - Z 21 -O- or ^{-Z 21 -O-C (= O} ) - and is, Z ²¹ is 1 to carbon atoms It is 12 alkylene groups and may contain a carbonyl group, an ester bond or an ether bond.
A is a hydrogen atom or a trifluoromethyl group.
Z ³ is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, -O-Z ^32- or -C (= O) -Z ^31- Z ^32- , and Z ³¹ is -O. -Or -NH-, Z ³² is an alkylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, or an alkenylene group having 2 to 6 carbon atoms. Yes, it may contain a carbonyl group, an ester bond, an ether bond or a hydroxy group.
R ^{41 to} R ⁴⁸ are monovalent hydrocarbon groups having 1 to 20 carbon atoms, which may independently contain heteroatoms. Further, ^{any two of R 43} , R ⁴⁴ and R ⁴⁵ , or any two of R ⁴⁶ , R ⁴⁷ and R ⁴⁸ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.
Q ^- represents a non-nucleophilic opposing ion. )
A step of applying any of the resist materials of 15.1 to 14 on a substrate and heat-treating to form a resist film, a step of exposing the resist film with high-energy rays, and an exposure using a developing solution. A pattern forming method including a step of developing a resist film.
16. Fifteen pattern forming methods in which the high energy ray is an ArF excimer laser having a wavelength of 193 nm or a KrF excimer laser having a wavelength of 248 nm.
17. A method for forming a pattern of 15 in which the high-energy ray is an electron beam or extreme ultraviolet light having a wavelength of 3 to 15 nm.

A resist material to which an acid generator of fluorosulfonic acid containing an iodinated benzene ring is added in addition to a polymer containing an iodine atom has a feature that acid diffusion is small because the molecular weight of iodine is large. Furthermore, since the absorption of EUV with a wavelength of 13.5 nm by iodine is very large, secondary electrons are generated from iodine during exposure, and an acid generator that generates fluorosulfonic acid without iodine in a polymer containing iodine atoms. The sensitivity is higher than when the above is added. These make it possible to construct a resist material having high sensitivity, low LWR and low CDU.

[Resist material]
The resist material of the present invention includes a polymer containing an iodine atom and a sulfonium salt or iodonium salt of an iodinated benzene ring-containing fluorosulfonic acid (collectively, these are also collectively referred to as an iodinated benzene ring-containing fluorosulfonic acid onium salt). Contains acid generators. The sulfonium salt and iodonium salt are acid generators that generate iodinated benzene ring-containing fluorosulfonic acid by light irradiation. To the resist material of the present invention, an acid generator different from this that generates a sulfonic acid, imic acid or methidoic acid may be added, or in combination with a bound type acid generator bound to the base polymer. May be good.

When light irradiation is performed in a state where the sulfonium salt of the iodinated benzene ring-containing fluorosulfonic acid is mixed with the sulfonic acid of a weaker acid or the sulfonium salt of a carboxylic acid, the iodinated benzene ring-containing fluorosulfonic acid and the above Weak acid sulfonic acid or carboxylic acid is also generated. Since not all acid generators are decomposed, there are undecomposed acid generators in the vicinity. Here, when the iodide benzene ring-containing fluorosulfonic acid and the sulfonic acid of a weaker acid and the sulfonium salt of the carboxylic acid coexist, the iodide benzene ring-containing fluorosulfonic acid and the sulfonic acid of the weak acid and the sulfonium of the carboxylic acid are present. Ion exchange with the salt occurs, a sulfonium salt of fluorosulfonic acid containing an iodide benzene ring is produced, and weak sulfonic acid and carboxylic acid are released. This is because the iodinated benzene ring-containing fluorosulfonate, which has higher strength as an acid, is more stable. On the other hand, ion exchange does not occur even if the sulfonium salt of fluorosulfonic acid containing an iodide benzene ring and the weak acid sulfonic acid or carboxylic acid are present. This ion exchange according to the order of acid strength occurs not only in the case of the sulfonium salt but also in the case of the iodonium salt. When combined as an acid generator of fluorosulfonic acid, the sulfonium and iodonium salts of weak acids function as quenchers. In addition, since iodine absorbs EUV having a wavelength of 13.5 nm extremely large, secondary electrons are generated during exposure, and the energy of the secondary electrons is transferred to the acid generator to promote decomposition, which is high. Increase sensitivity. In particular, this effect is high when the number of iodine substitutions is 3 or more.

In order to improve the LWR, it is effective to suppress the aggregation of the polymer and the acid generator. In order to suppress the aggregation of the polymer, it is effective to reduce the difference between hydrophobicity and hydrophilicity, lower the glass transition point (Tg), or lower the molecular weight of the polymer. Specifically, it is effective to reduce the polar difference between the hydrophobic acid unstable group and the hydrophilic adhesive group, and to reduce Tg by using a compact adhesive group such as a monocyclic lactone. Is the target. In order to suppress the aggregation of the acid generator, it is effective to introduce a substituent into the cation moiety of triphenylsulfonium. In particular, triphenylsulfonium formed only of an aromatic group has a heterogeneous structure and is compatible with a methacrylate polymer for ArF formed of an alicyclic protecting group and an adhesive group of a lactone. Is low. As the substituent to be introduced into triphenylsulfonium, an alicyclic group similar to that used in the base polymer or a lactone can be considered. Since the sulfonium salt is hydrophilic, when a lactone is introduced, the hydrophilicity becomes too high, the compatibility with the polymer decreases, and the sulfonium salt aggregates. By introducing a hydrophobic alkyl group, the sulfonium salt can be uniformly dispersed in the resist film. International Publication No. 2011/048919 proposes a method for improving LWR by introducing an alkyl group into a sulfonium salt that generates a sulfonium acid having a fluorinated α-position.

The onium salt of fluorosulfonic acid containing an iodinated benzene ring has low diffusion because iodine having a large atomic weight is introduced into the anion portion, and further has high compatibility with a polymer having iodine, so that it has high dispersibility. Excellent, which improves LWR and CDU.

The effect of improving LWR and CDU by the benzene ring-containing fluorosulfonic acid onium salt is effective in both positive pattern formation and negative pattern formation by alkaline aqueous solution development and negative pattern formation in organic solvent development.

[Iodinated benzene ring-containing fluorosulfonic acid sulfonium salt and iodonium salt]
The sulfonium salt and iodonium salt of the iodinated benzene ring-containing fluorosulfonic acid are represented by the following formulas (A-1) and (A-2), respectively.

In the formulas (A-1) and (A-2), L ¹ is an alkylene group having 1 to 6 carbon atoms which may contain a single bond, an ether bond or an ester bond, or an ether bond or an ester bond. The alkylene group may be linear, branched or cyclic.

R ¹ contains a hydroxy group, a carboxy group, a fluorine atom, a chlorine atom, a bromine atom or an amino group, or a fluorine atom, a chlorine atom, a bromine atom, a hydroxy group, an amino group or an alkoxy group having 1 to 10 carbon atoms. May be an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxycarbonyl group having 2 to 10 carbon atoms, an acyloxy group having 2 to 20 carbon atoms, or an alkylsulfonyloxy group having 1 to 20 carbon atoms. , Or -NR ^8- C (= O) -R ⁹ or -NR ^8- C (= O) -O-R ⁹ , where R ⁸ is a hydrogen atom or halogen atom, hydroxy group, 1 to 1 carbon atoms. An alkyl group having 1 to 6 carbon atoms which may contain an alkoxy group of 6 and an acyl group having 2 to 6 carbon atoms or an acyloxy group having 2 to 6 carbon atoms, and R ⁹ is an alkyl having 1 to 16 carbon atoms. A group, an alkenyl group having 2 to 16 carbon atoms, or an aryl group having 6 to 12 carbon atoms, which is a halogen atom, a hydroxy group, an alkoxy group having 1 to 6 carbon atoms, an acyl group having 2 to 6 carbon atoms, or a carbon number of carbon atoms. It may contain 2 to 6 acyloxy groups. The alkyl group, alkoxy group, alkoxycarbonyl group, acyloxy group, acyl group and alkenyl group may be linear, branched or cyclic.

Of these, as R ¹ , a hydroxy group, −NR ^8- C (= O) −R ⁹ , a fluorine atom, a chlorine atom, a bromine atom, a methyl group, a methoxy group and the like are preferable.

R ² is a single bond or a divalent linking group having 1 to 20 carbon atoms when p is 1, and a trivalent or tetravalent linking group having 1 to 20 carbon atoms when p is 2 or 3. Yes, the linking group may contain an oxygen atom, a sulfur atom or a nitrogen atom.

Rf ^{1 to Rf 4} are independently hydrogen atoms, fluorine atoms or trifluoromethyl groups, but at least one of them is a fluorine atom or trifluoromethyl group. Further, Rf ¹ and Rf ² may be combined to form a carbonyl group. In particular, it is preferable that both ^{Rf 3} and Rf ^{4 are fluorine atoms.}

R ³ , R ⁴ , R ⁵ , R ⁶ and R ⁷ are monovalent hydrocarbon groups having 1 to 20 carbon atoms, which may independently contain heteroatoms. Further, ^{any two of R 3} , R ⁴ and R ⁵ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. The monovalent hydrocarbon group may be linear, branched or cyclic, and specific examples thereof include an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, and 2 to 12 carbon atoms. Examples thereof include an alkynyl group, an aryl group having 6 to 20 carbon atoms, and an aralkyl group having 7 to 12 carbon atoms. Further, some or all of the hydrogen atoms of these groups are substituted with a hydroxy group, a carboxy group, a halogen atom, a cyano group, an amide group, a nitro group, a mercapto group, a sulton group, a sulfone group or a sulfonium salt-containing group. Alternatively, some of the carbon atoms of these groups may be substituted with ether bonds, ester bonds, carbonyl groups, carbonate groups or sulfonic acid ester bonds.

p is an integer that satisfies 1 ≦ p ≦ 3. q and r are integers that satisfy 1 ≦ q ≦ 5, 0 ≦ r ≦ 3, and 1 ≦ q + r ≦ 5. q is preferably an integer satisfying 1 ≦ q ≦ 3, more preferably 2 or 3. r is preferably an integer satisfying 0 ≦ r ≦ 2.

The cation of the sulfonium salt represented by the formula (A-1) is preferably the cation represented by the following formula (A-3) or (A-4), and the iodonium salt represented by the formula (A-2). As the cation of, the one represented by the following formula (A-5) is preferable.

In the formula, R ^{11 to} R ¹⁸ are independently monovalent hydrocarbon groups having 1 to 14 carbon atoms. The monovalent hydrocarbon group includes an alkyl group having 1 to 14 carbon atoms, an alkenyl group having 2 to 14 carbon atoms, an aryl group having 6 to 14 carbon atoms, an aralkyl group having 7 to 14 carbon atoms, a hydroxy group and a carboxy group. , Halogen atom, cyano group, amide group, nitro group, sulton group, sulfone group or sulfonium salt containing group. Further, a part or all of the hydrogen atoms of the monovalent hydrocarbon group are substituted with a hydroxy group, a carboxy group, a halogen atom, a cyano group, an amide group, a nitro group, a sulton group, a sulfone group or a sulfonium salt-containing group. Alternatively, some of the carbon atoms of these groups may be substituted with ether bonds, ester bonds, carbonyl groups, carbonate groups or sulfonic acid ester bonds. L ² is a single bond, a methylene group, an ether bond, a thioether bond, or a carbonyl group. a to h are independently integers of 0 to 5.

Examples of the cation of the sulfonium salt represented by the formula (A-1) include, but are not limited to, those shown below.

Examples of the cation of the iodonium salt represented by the formula (A-2) include, but are not limited to, those shown below.

Examples of the anion of the sulfonium salt represented by the formula (A-1) and the iodonium salt represented by the formula (A-2) include, but are not limited to, those shown below.

As a method for synthesizing the sulfonium salt represented by the formula (A-1) and the iodonium salt represented by the formula (A-2), a sulfonium salt or iodonium having a weaker acid than the iodinated bayzoyloxy group-containing fluorinated sulfonic acid. Examples include a method of ion exchange with salt. Examples of the acid weaker than the fluorinated sulfonic acid bonded to benzene substituted with iodine include hydrochloric acid, carbonic acid and the like. It is also possible to synthesize a sodium salt or ammonium salt of fluorinated sulfonic acid bonded to benzene substituted with iodine by ion exchange with a sulfonium chloride salt or an iodonium chloride salt.

In the resist material of the present invention, the content of the benzene ring-containing fluorosulfonic acid onium salt is 0.01 to 1,000 mass by mass with respect to 100 parts by mass of the base polymer, which will be described later, in terms of sensitivity and acid diffusion suppressing effect. Parts are preferable, and 0.05 to 500 parts by mass is more preferable. The iodinated benzene ring-containing fluorosulfonic acid onium salt can be used alone or in combination of two or more.

[Base polymer]
The base polymer contained in the resist material of the present invention contains a polymer having an iodine atom (hereinafter, also referred to as polymer A). The polymer A includes a repeating unit represented by the following formula (a1) (hereinafter, also referred to as a repeating unit a1) or a repeating unit represented by the following formula (a2) (hereinafter, also referred to as a repeating unit a2). Is preferable.

In the formula, ^RA is independently a hydrogen atom or a methyl group. R ²¹ is a single bond or a methylene group. R ²² is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. The alkyl group is preferably linear or branched. X ¹ represents a single bond, an ether bond, an ester bond, an amide bond, -C (= O) -O- R 23 -, a phenylene group, -Ph-C (= O) -O-R 24 -, or -Ph ^{-R 25 -O-C (= O} ) -R 26 - is it, Ph is a phenylene group. R ²³ is an alkylene group having 1 to 10 carbon atoms, may be linear, branched, or cyclic, and may contain an ether bond or an ester bond. R ²⁴ , R ²⁵ and R ²⁶ are independently single-bonded or linear or branched alkylene groups having 1 to 6 carbon atoms.

m and n are integers that satisfy 1 ≦ m ≦ 5, 0 ≦ n ≦ 4, and 1 ≦ m + n ≦ 5. The presence of a hydroxy group increases the efficiency of secondary electron generation and increases the sensitivity. Therefore, n is preferably an integer satisfying 1 ≦ n ≦ 3. m is preferably an integer satisfying 1 ≦ m ≦ 3.

Examples of the monomer that gives the repeating unit a1 include, but are not limited to, those shown below. In the following formula, ^RA is the same as described above.

Examples of the monomer that gives the repeating unit a2 include, but are not limited to, those shown below. In the following formula, ^RA is the same as described above.

The repeating units a1 and a2 can be used alone or in combination of two or more.

When the resist material of the present invention is of the positive type, the polymer A preferably further contains a repeating unit containing an acid unstable group. The repeating unit containing the acid-labile group includes a repeating unit represented by the following formula (b1) (hereinafter, also referred to as a repeating unit b1) or a repeating unit represented by the formula (b2) (hereinafter, repeating unit). b2) is preferable. When the resist material of the present invention is a negative type, it is preferable that the polymer A does not contain a repeating unit containing an acid unstable group.

In the formula, ^RA is independently a hydrogen atom or a methyl group. Y ¹ is a single bond, a phenylene group or a naphthylene group, or a linking group having 1 to 12 carbon atoms containing an ester bond or a lactone ring. Y ² is a single bond or an ester bond. R ³¹ and R ³² are independently acid-labile groups. R ³³ is a fluorine atom, a trifluoromethyl group, a cyano group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an acyl group having 2 to 7 carbon atoms, and an acyloxy group having 2 to 7 carbon atoms. , Or an alkoxycarbonyl group having 2 to 7 carbon atoms. R ³⁴ is a single bond or an alkylene group having 1 to 6 carbon atoms, and a part of the carbon atom thereof may be substituted with an ether bond or an ester bond. Although t is an integer of 1 or 2 and s is an integer of 0 to 4, 1 ≦ t + s ≦ 5. The alkyl group, alkoxy group, acyl group, acyloxy group and alkoxycarbonyl group may be linear, branched or cyclic. The alkylene group having 1 to 6 carbon atoms is preferably linear or branched.

Examples of the monomer that gives the repeating unit b1 include, but are not limited to, those shown below. In the following formula, ^RA and R ³¹ are the same as described above.

Examples of the monomer that gives the repeating unit b2 include, but are not limited to, those shown below. In the following formula, ^RA and R ³² are the same as described above.

Examples of the acid unstable group represented by ^{R 31} and R ³² in the repeating units b1 and b2 include those described in JP2013-83033A and JP2013-83821A.

Typically, the acid unstable group includes those represented by the following formulas (AL-1) to (AL-3).

In the formulas (AL-1) and (AL-2), ^RL1 and ^RL2 are monovalent hydrocarbon groups and may contain heteroatoms such as oxygen atom, sulfur atom, nitrogen atom and fluorine atom. .. The monovalent hydrocarbon group may be linear, branched or cyclic, and an alkyl group having 1 to 40 carbon atoms is preferable, and an alkyl group having 1 to 20 carbon atoms is more preferable. In the formula (AL-1), x is an integer of 0 to 10, and an integer of 1 to 5 is preferable.

In the formula (AL-2), R ^L3 and R ^L4 are independently hydrogen atoms or monovalent hydrocarbon groups, and contain heteroatoms such as oxygen atom, sulfur atom, nitrogen atom and fluorine atom. May be good. The monovalent hydrocarbon group may be linear, branched or cyclic, and an alkyl group having 1 to 20 carbon atoms is preferable. Further, any two of R ^L2, R ^L3 and R ^L4, may form a ring of 3 to 20 carbon atoms with the carbon atom or carbon and oxygen atoms to which it binds them combine with each other. As the ring, a ring having 4 to 16 carbon atoms is preferable, and an alicyclic ring is particularly preferable.

In formula (AL-3), ^RL5 , ^RL6 and ^RL7 are independently monovalent hydrocarbon groups, even if they contain heteroatoms such as oxygen atom, sulfur atom, nitrogen atom and fluorine atom. Good. The monovalent hydrocarbon group may be linear, branched or cyclic, and an alkyl group having 1 to 20 carbon atoms is preferable. Further, any two of R ^L5, R ^L6 and R ^L7, may form a ring of 3 to 20 carbon atoms with the carbon atom bonded these combined with each other. As the ring, a ring having 4 to 16 carbon atoms is preferable, and an alicyclic ring is particularly preferable.

The polymer A may further contain a repeating unit c containing a phenolic hydroxy group as an adhesive group. The repeating unit c can be used alone or in combination of two or more.

Examples of the monomer that gives the repeating unit c include, but are not limited to, those shown below. In the following formula, ^RA is the same as described above.

The polymer A may further contain, as other adhesive groups, a repeating unit d containing a hydroxy group other than the phenolic hydroxy group, a carboxy group, a lactone ring, an ether bond, an ester bond, a carbonyl group or a cyano group. The repeating unit d may be used alone or in combination of two or more.

Examples of the monomer that gives the repeating unit d include, but are not limited to, those shown below. In the following formula, ^RA is the same as described above.

Polymer A may further contain a repeating unit e derived from indene, benzofuran, benzothiophene, acenaphthylene, chromone, coumarin, norbornadiene or derivatives thereof. The repeating unit e can be used alone or in combination of two or more.

Examples of the monomer that gives the repeating unit e include, but are not limited to, those shown below.

Polymer A may further contain a repeating unit f derived from styrene, vinylnaphthalene, vinylanthracene, vinylpyrene, methyleneindane, vinylpyridine or vinylcarbazole. The repeating unit f can be used alone or in combination of two or more.

The polymer A may further contain a repeating unit g derived from an onium salt containing a polymerizable olefin. Japanese Unexamined Patent Publication No. 2005-84365 proposes a sulfonium salt or an iodonium salt containing a polymerizable olefin that generates a specific sulfonic acid. Japanese Unexamined Patent Publication No. 2006-178317 proposes a sulfonium salt in which sulfonic acid is directly linked to the main chain.

The preferred repeating unit g is a repeating unit represented by the following formula (g1) (hereinafter, also referred to as a repeating unit g1) and a repeating unit represented by the following formula (g2) (hereinafter, also referred to as a repeating unit g2). , And a repeating unit represented by the following formula (g3) (hereinafter, also referred to as a repeating unit g3). The repeating units g1 to g3 can be used alone or in combination of two or more.

In the formula, ^RA is independently a hydrogen atom or a methyl group. Z ¹ is a single bond, a phenylene group, -O-Z ¹² -, or ^{-C (= O) -Z 11 -Z} 12 - a and, Z ¹¹ is -O- or -NH-, Z ¹² Is an alkylene group having 1 to 6 carbon atoms, an alkenylene group having 2 to 6 carbon atoms, or a phenylene group, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. Z ² is a single ^{bond, -Z 21 -C (= O)} -O -, - Z 21 -O- or ^{-Z 21 -O-C (= O} ) - and is, Z ²¹ is 1 to carbon atoms It is 12 alkylene groups and may contain a carbonyl group, an ester bond or an ether bond. A is a hydrogen atom or a trifluoromethyl group. Z ³ is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, -O-Z ^32- or -C (= O) -Z ^31- Z ^32- , and Z ³¹ is -O. -Or -NH-, Z ³² is an alkylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, or an alkenylene group having 2 to 6 carbon atoms. Yes, it may contain a carbonyl group, an ester bond, an ether bond or a hydroxy group.

In the formulas (g1) to (g3), R ^{41 to} R ⁴⁸ are monovalent hydrocarbon groups having 1 to 20 carbon atoms which may independently contain a hetero atom. Further, ^{any two of R 43} , R ⁴⁴ and R ⁴⁵ , or any two of R ⁴⁶ , R ⁴⁷ and R ⁴⁸ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. As the sulfonium cation in the formulas (g2) and (g3), those represented by the above-mentioned formula (A-3) or (A-4) are preferable, and specific examples thereof are in the formula (A-1). Examples of the sulfonium cation of the above include those similar to those described above.

Wherein (g1), Q ^- is a non-nucleophilic counter ion. Examples of the non-nucleophilic counter ion include a halide ion such as chloride ion and bromide ion, a trifurate ion, a fluoroalkyl sulfonate ion such as 1,1,1-trifluoroethanesulfonate ion, and a nonafluorobutane sulfonate ion, and Toshi. Rate ion, benzene sulfonate ion, 4-fluorobenzene sulfonate ion, aryl sulfonate ion such as 1,2,3,4,5-pentafluorobenzene sulfonate ion, alkyl sulfonate ion such as mesylate ion, butane sulfonate ion, bis ( Examples include imide ions such as trifluoromethylsulfonyl) imide ion, bis (perfluoroethylsulfonyl) imide ion, and bis (perfluorobutylsulfonyl) imide ion, and methide ions such as tris (trifluoromethylsulfonyl) methide ion and tris (perfluoroethylsulfonyl) methide ion. Be done.

Examples of the non-nucleophilic counter ion include a sulfonic acid ion in which the α-position represented by the following formula (K-1) is replaced with a fluorine atom, and α and β represented by the following formula (K-2). Examples thereof include a sulfonic acid ion in which the position is substituted with a fluorine atom.

In formula (K-1), R ⁵¹ is a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms, or an aryl having 6 to 20 carbon atoms. It is a group and may contain an ether bond, an ester bond, a carbonyl group, a lactone ring or a fluorine atom.

In the formula (K-2), R ⁵² is a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms, an acyl group having 2 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms. , Or an aryl group or an aryloxy group having 6 to 20 carbon atoms, which may contain an ether bond, an ester bond, a carbonyl group or a lactone ring.

Examples of the monomer that gives the repeating unit g1 include, but are not limited to, those shown below. In the following formula, ^RA and Q ^- are the same as described above.

Examples of the monomer that gives the repeating unit g2 include, but are not limited to, those shown below. In the following formula, ^RA is the same as described above.

Examples of the monomer that gives the repeating unit g3 include, but are not limited to, those shown below. In the following formula, ^RA is the same as described above.

By binding an acid generator to the polymer main chain, acid diffusion can be reduced and deterioration of resolution due to blurring of acid diffusion can be prevented. Further, the edge roughness is improved by uniformly dispersing the acid generator.

The polymer A for a positive resist material contains a repeating unit a1 or a2 containing an iodine atom, and additionally contains a repeating unit b1 or b2 containing an acid unstable group. In this case, the content ratios of the repeating units a1, a2, b1, b2, c, d, e, f and g are 0 ≦ a1 <1.0, 0 ≦ a2 <1.0, 0 <a1 + a2 <1.0. , 0 ≦ b1 <1.0, 0 ≦ b2 <1.0, 0 <b1 + b2 <1.0, 0 ≦ c ≦ 0.9, 0 ≦ d ≦ 0.9, 0 ≦ e ≦ 0.8, 0 ≦ f ≦ 0.8 and 0 ≦ g ≦ 0.5 are preferable, and 0 ≦ a1 ≦ 0.9, 0 ≦ a2 ≦ 0.9, 0.1 ≦ a1 + a2 ≦ 0.9, 0 ≦ b1 ≦ 0. 9, 0 ≦ b2 ≦ 0.9, 0.1 ≦ b1 + b2 ≦ 0.9, 0 ≦ c ≦ 0.8, 0 ≦ d ≦ 0.8, 0 ≦ e ≦ 0.7, 0 ≦ f ≦ 0. 7 and 0 ≦ g ≦ 0.4 are more preferable, and 0 ≦ a1 ≦ 0.8, 0 ≦ a2 ≦ 0.8, 0.1 ≦ a1 + a2 ≦ 0.8, 0 ≦ b1 ≦ 0.8, 0 ≦ b2 ≦ 0.8, 0.1 ≦ b1 + b2 ≦ 0.8, 0 ≦ c ≦ 0.75, 0 ≦ d ≦ 0.75, 0 ≦ e ≦ 0.6, 0 ≦ f ≦ 0.6, and 0 ≦ g ≦ 0.3 is more preferable. When the repeating unit g is at least one selected from the repeating units g1 to g3, g = g1 + g2 + g3. Further, a1 + a2 + b1 + b2 + c + d + e + f + g = 1.0.

On the other hand, the polymer A for the negative resist material does not necessarily require an acid unstable group. Examples of such a base polymer include a repeating unit a1 or a2 containing an iodine atom and a repeating unit c, and if necessary, further containing a repeating unit d, e, f and / or g. The content ratio of these repeating units is 0 ≦ a1 <1.0, 0 ≦ a2 <1.0, 0 <a1 + a2 <1.0, 0 <c <1.0, 0 ≦ d ≦ 0.9, 0. ≦ e ≦ 0.8, 0 ≦ f ≦ 0.8, and 0 ≦ g ≦ 0.5 are preferable, and 0 ≦ a1 ≦ 0.8, 0 ≦ a2 ≦ 0.8, 0.1 ≦ a1 + a2 ≦ 0. 8, 0.2 ≦ c ≦ 0.9, 0 ≦ d ≦ 0.8, 0 ≦ e ≦ 0.7, 0 ≦ f ≦ 0.7, and 0 ≦ g ≦ 0.4 are more preferable, and 0 ≦ a1 ≦ 0.7, 0 ≦ a2 ≦ 0.7, 0.2 ≦ a1 + a2 ≦ 0.7, 0.3 ≦ c ≦ 0.8, 0 ≦ d ≦ 0.75, 0 ≦ e ≦ 0.6, 0 ≦ f ≦ 0.6 and 0 ≦ g ≦ 0.3 are more preferable. When the repeating unit g is at least one selected from the repeating units g1 to g3, g = g1 + g2 + g3. Further, a1 + a2 + c + d + e + f + g = 1.0.

In order to synthesize the polymer A, for example, the above-mentioned monomer giving a repeating unit may be thermally polymerized by adding a radical polymerization initiator in an organic solvent.

Examples of the organic solvent used at the time of polymerization include toluene, benzene, tetrahydrofuran, diethyl ether, dioxane and the like. As the polymerization initiator, 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis (2,4-dimethylvaleronitrile), dimethyl-2,2-azobis (2-methylpropio) Nate), benzoyl peroxide, lauroyl peroxide and the like. The reaction temperature is preferably 50 to 80 ° C., and the reaction time is preferably 2 to 100 hours, more preferably 5 to 20 hours.

When copolymerizing a monomer containing a hydroxy group, the hydroxy group may be replaced with an acetal group that is easily deprotected with an acid such as an ethoxyethoxy group at the time of polymerization, and then deprotected with a weak acid and water after the polymerization. Alkali hydrolysis may be carried out after polymerization by substituting with an acetyl group, a formyl group, a pivaloyl group or the like.

When copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, acetoxystyrene or acetoxyvinylnaphthalene is used instead of hydroxystyrene or hydroxyvinylnaphthalene, and after polymerization, the acetoxy group is deprotected by the alkali hydrolysis to obtain a hydroxystyrene unit or It may be a hydroxyvinylnaphthalene unit.

As the base for alkaline hydrolysis, aqueous ammonia, triethylamine and the like can be used. The reaction temperature is preferably -20 to 100 ° C., more preferably 0 to 60 ° C., and the reaction time is preferably 0.2 to 100 hours, more preferably 0.5 to 20 hours.

The polystyrene-equivalent weight average molecular weight (Mw) of the polymer A by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent is preferably 1,000 to 500,000, more preferably 2,000 to 30. It is 000. When Mw is in the above range, heat resistance and alkali solubility are good.

Further, when the molecular weight distribution (Mw / Mn) of the polymer A is wide, foreign matter is seen on the pattern or the shape of the pattern is deteriorated after exposure due to the presence of the polymer having a low molecular weight or a high molecular weight. There is a risk. As the pattern rule becomes finer, the influence of Mw and the molecular weight distribution tends to increase. Therefore, in order to obtain a resist material suitable for fine pattern dimensions, the molecular weight distribution of the base polymer is 1.0 to 2. It is preferable that the dispersion is as narrow as .0, particularly 1.0 to 1.5.

The base polymer may contain two or more polymers A having different composition ratios, Mw, and molecular weight distributions. Further, a polymer different from the polymer A may be contained as long as the effect of the present invention is not impaired, but it is preferable not to contain the polymer.

[Other ingredients]
A resist material containing the above-mentioned onium salt of benzene ring-containing fluorosulfonic acid and a base polymer, an organic solvent, an acid generator other than the onium salt of fluorosulfonic acid containing a benzene ring of iodide, a surfactant, a dissolution inhibitor, and a cross-linking. By appropriately combining and blending agents and the like according to the purpose to form a positive resist material and a negative resist material, the dissolution rate of the base polymer in the developing solution is accelerated by a catalytic reaction in the exposed portion. It can be a highly sensitive positive resist material or a negative resist material. In this case, the dissolution contrast and resolution of the resist film are high, there is an exposure margin, the process adaptability is excellent, the pattern shape after exposure is good, and acid diffusion can be suppressed in particular, so that the difference in coarseness and density is small. From these facts, it is highly practical and can be made very effective as a resist material for VLSI. In particular, when a chemically amplified positive resist material utilizing an acid catalyst reaction is used, it can be made more sensitive and has more excellent properties, which is extremely useful.

Examples of the organic solvent include ketones such as cyclohexanone, cyclopentanone, and methyl-2-n-pentyl ketone described in paragraphs [0144] to [0145] of JP-A-2008-111103, 3-methoxybutanol, and the like. Alcohols such as 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether , Ethers such as propylene glycol dimethyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, acetate Examples thereof include esters such as tert-butyl, tert-butyl propionate and propylene glycol mono-tert-butyl ether acetate, lactones such as γ-butyrolactone, and mixed solvents thereof. These solvents can be used alone or in admixture of two or more.

In the resist material of the present invention, the content of the organic solvent is preferably 100 to 10,000 parts by mass, more preferably 200 to 8,000 parts by mass with respect to 100 parts by mass of the base polymer.

The resist material of the present invention may contain an acid generator other than the iodinated benzene ring-containing fluorosulfonic acid onium salt (hereinafter, also referred to as other acid generator) as long as the effects of the present invention are not impaired. Examples of other acid generators include compounds that generate acids in response to active light or radiation (photoacid generators). The component of the photoacid generator may be any compound that generates an acid by irradiation with high energy rays, but an acid generator that generates sulfonic acid, imidic acid or methidoic acid is preferable. Suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethanes, N-sulfonyloxyimides, oxime-O-sulfonate type acid generators and the like. Specific examples of the acid generator are described in paragraphs [0122] to [0142] of JP-A-2008-111103. Other acid generators can be used alone or in admixture of two or more. The content of the other acid generator is preferably 0 to 200 parts by mass, more preferably 0.1 to 100 parts by mass with respect to 100 parts by mass of the base polymer.

Examples of the surfactant include those described in paragraphs [0165] to [0166] of JP-A-2008-111103. By adding a surfactant, the coatability of the resist material can be further improved or controlled. The surfactant may be used alone or in combination of two or more. In the resist material of the present invention, the content of the surfactant is preferably 0.0001 to 10 parts by mass with respect to 100 parts by mass of the base polymer.

In the case of a positive resist material, by blending a dissolution inhibitor, the difference in dissolution rate between the exposed portion and the unexposed portion can be further increased, and the resolution can be further improved. In the case of a negative resist material, a negative pattern can be obtained by reducing the dissolution rate of the exposed portion by adding a cross-linking agent.

As the dissolution inhibitor, the hydrogen atom of the phenolic hydroxy group of a compound having a molecular weight of preferably 100 to 1,000, more preferably 150 to 800 and containing two or more phenolic hydroxy groups in the molecule is acid. A compound in which the hydrogen atom of the carboxy group of a compound substituted with an unstable group as a whole at a ratio of 0 to 100 mol% or a compound containing a carboxy group in the molecule is averaged at a ratio of 50 to 100 mol% as a whole with an acid unstable group. Examples thereof include compounds substituted with. Specific examples thereof include bisphenol A, trisphenol, phenolphthalein, cresol novolac, naphthalenecarboxylic acid, adamantancarboxylic acid, hydroxy group of cholic acid, and compounds in which the hydrogen atom of the carboxy group is replaced with an acid unstable group. For example, it is described in paragraphs [0155] to [0178] of JP-A-2008-122932.

When the resist material of the present invention is a positive resist material, the content of the dissolution inhibitor is preferably 0 to 50 parts by mass, more preferably 5 to 40 parts by mass with respect to 100 parts by mass of the base polymer. The dissolution inhibitor may be used alone or in combination of two or more.

The cross-linking agent includes an epoxy compound, a melamine compound, a guanamine compound, a glycoluril compound or a urea compound, an isocyanate compound, and an azido compound substituted with at least one group selected from a methylol group, an alkoxymethyl group and an acyloxymethyl group. , Compounds containing a double bond such as an alkenyl ether group, and the like. These may be used as additives or may be introduced as pendant groups in the polymer side chain. Further, a compound containing a hydroxy group can also be used as a cross-linking agent. The cross-linking agent may be used alone or in combination of two or more.

Examples of the epoxy compound include tris (2,3-epoxypropyl) isocyanurate, trimethylolmethane triglycidyl ether, trimethylolpropane triglycidyl ether, and trimethylolethane triglycidyl ether.

Examples of the melamine compound include a compound in which 1 to 6 methylol groups of hexamethylol melamine, hexamethoxymethyl melamine, and hexamethylol melamine are methoxymethylated or a mixture thereof, hexamethoxyethyl melamine, hexaacyloxymethyl melamine, and hexamethylol melamine. Examples thereof include a compound in which 1 to 6 methylol groups of the above are acyloxymethylated, or a mixture thereof.

Examples of the guanamine compound include a compound in which 1 to 4 methylol groups of tetramethylol guanamine, tetramethoxymethyl guanamine, and tetramethylol guanamine are methoxymethylated or a mixture thereof, and one of tetramethoxyethyl guanamine, tetraacyloxyguanamine, and tetramethylol guanamine. Examples thereof include a compound in which ~ 4 methylol groups are acyloxymethylated, or a mixture thereof.

Examples of the glycol uryl compound include tetramethylol glycol uryl, tetramethoxyglycol uryl, tetramethoxymethyl glycol uryl, and tetramethylol glycol uryl, a compound in which 1 to 4 methylol groups are methoxymethylated or a mixture thereof, and methylol of tetramethylol glycol uryl. Examples thereof include a compound in which 1 to 4 groups are acyloxymethylated or a mixture thereof. Examples of the urea compound include tetramethylol urea, tetramethoxymethyl urea, a compound in which 1 to 4 methylol groups of tetramethylol urea are methoxymethylated, or a mixture thereof, and tetramethoxyethyl urea.

Examples of the isocyanate compound include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, cyclohexane diisocyanate and the like.

Examples of the azide compound include 1,1'-biphenyl-4,4'-bis azide, 4,4'-methylidene bis azide, and 4,4'-oxybis azide.

Examples of the compound containing an alkenyl ether group include ethylene glycol divinyl ether, triethylene glycol divinyl ether, 1,2-propanediol divinyl ether, 1,4-butanediol divinyl ether, tetramethylene glycol divinyl ether, neopentyl glycol divinyl ether, and the like. Examples thereof include trimethylolpropane trivinyl ether, hexanediol divinyl ether, 1,4-cyclohexanediol divinyl ether, pentaerythritol trivinyl ether, pentaerythritol tetravinyl ether, sorbitol tetravinyl ether, sorbitol pentavinyl ether, and trimethylolpropanetrivinyl ether.

When the resist material of the present invention is a negative resist material, the content of the cross-linking agent is preferably 0.1 to 50 parts by mass, more preferably 1 to 40 parts by mass with respect to 100 parts by mass of the base polymer.

The resist material of the present invention may contain a quencher. Examples of the quencher include conventional basic compounds. Conventional basic compounds include primary, secondary and tertiary aliphatic amines, mixed amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxy group, and sulfonyl groups. Examples thereof include a nitrogen-containing compound having a hydroxy group, a nitrogen-containing compound having a hydroxy group, a nitrogen-containing compound having a hydroxyphenyl group, an alcoholic nitrogen-containing compound, amides, imides, and carbamates. In particular, primary, secondary and tertiary amine compounds described in paragraphs [0146] to [0164] of JP-A-2008-111103, particularly hydroxy groups, ether bonds, ester bonds, lactone rings, and the like. A cyano group, an amine compound having a sulfonic acid ester bond, a compound having a carbamate group described in Japanese Patent No. 3790649, and the like are preferable. By adding such a basic compound, for example, the diffusion rate of the acid in the resist film can be further suppressed or the shape can be corrected.

In addition, examples of the quencher include onium salts such as sulfonium salts, iodonium salts, and ammonium salts of sulfonic acids and carboxylic acids whose α-position is not fluorinated, which is described in JP-A-2008-158339. Sulfonic acid, imidic acid or methidoic acid with fluorinated α-position is required to deprotect the acid instability group of the carboxylic acid ester, but salt exchange with onium salt with fluorinated α-position. Releases sulfonic acids or carboxylic acids whose α-position is not fluorinated. Sulfonic acids and carboxylic acids whose α-position is not fluorinated do not undergo a deprotection reaction and therefore function as a quencher.

Further, the onium carboxylic acid salt represented by the following formula (1) can also be suitably used as a quencher.

In formula (1), R ¹⁰¹ is a monovalent hydrocarbon group having 1 to 40 carbon atoms which may contain a hetero atom. The monovalent hydrocarbon group may be linear, branched or cyclic, and specific examples thereof include an alkyl group having 1 to 40 carbon atoms, an alkenyl group having 2 to 40 carbon atoms, and 2 to 40 carbon atoms. Examples thereof include an alkynyl group, an aryl group having 6 to 40 carbon atoms, and an aralkyl group having 7 to 40 carbon atoms. Further, some or all of the hydrogen atoms of these groups are substituted with a hydroxy group, a carboxy group, a halogen atom, a cyano group, an amide group, a nitro group, a mercapto group, a sulton group, a sulfone group or a sulfonium salt-containing group. Alternatively, some of the carbon atoms of these groups may be substituted with ether bonds, ester bonds, carbonyl groups, carbonate groups or sulfonic acid ester bonds.

Wherein (1), M _A ⁺ represents an onium cation. Examples of the onium cation include sulfonium cations, iodonium cations, ammonium cations, etc., which are represented by the above-mentioned sulfonium cations represented by the formula (A-3) or (A-4) or the formula (A-5). The iodonium cation to be produced is preferable.

As the anion moiety of the carboxylic acid onium salt, those represented by the following formula (2) are preferable.

In formula (2), R ¹⁰² and R ¹⁰³ are independently hydrogen atoms, fluorine atoms, or trifluoromethyl groups, respectively. R ¹⁰⁴ is a monovalent hydrocarbon group having 1 to 35 carbon atoms which may contain a hydrogen atom, a hydroxy group and a hetero atom. The monovalent hydrocarbon group may be linear, branched or cyclic, and specific examples thereof include an alkyl group having 1 to 35 carbon atoms, an alkenyl group having 2 to 35 carbon atoms, and 2 to 2 carbon atoms. Examples thereof include an alkynyl group having 35 carbon atoms, an aryl group having 6 to 35 carbon atoms, and an aralkyl group having 7 to 35 carbon atoms. Further, some or all of the hydrogen atoms of these groups are substituted with a hydroxy group, a carboxy group, a halogen atom, a cyano group, an amide group, a nitro group, a mercapto group, a sulton group, a sulfone group or a sulfonium salt-containing group. Alternatively, some of the carbon atoms of these groups may be substituted with ether bonds, ester bonds, carbonyl groups, carbonate groups or sulfonic acid ester bonds.

Further, as the citrate, the polymer type citrate described in JP-A-2008-239918 can be mentioned. This enhances the rectangularity of the resist after patterning by orienting it on the surface of the resist after coating. The polymer-type quencher also has the effect of preventing the film from being reduced and the pattern top from being rounded when a protective film for immersion exposure is applied.

In the resist material of the present invention, the content of the quencher is preferably 0 to 5 parts by mass, more preferably 0 to 4 parts by mass with respect to 100 parts by mass of the base polymer. The quencher can be used alone or in combination of two or more.

The resist material of the present invention may contain a water repellency improver in order to improve the water repellency of the resist surface after spin coating. The water repellency improver can be used for immersion lithography without a top coat. As the water repellency improver, a polymer compound containing an alkyl fluoride group, a polymer compound containing a 1,1,1,3,3,3-hexafluoro-2-propanol residue having a specific structure, and the like are preferable, and in particular, It is exemplified in Japanese Patent Application Laid-Open No. 2007-297590, Japanese Patent Application Laid-Open No. 2008-111103 and the like. The water repellency improver needs to be dissolved in an organic solvent developer. The water repellency improver having the above-mentioned specific 1,1,1,3,3,3-hexafluoro-2-propanol residue has good solubility in a developing solution. As a water repellency improving agent, a polymer compound containing a repeating unit containing an amino group or an amine salt is highly effective in preventing evaporation of an acid in PEB and preventing poor opening of a hole pattern after development. The water repellency improver may be used alone or in combination of two or more. In the resist material of the present invention, the content of the water repellency improver is preferably 0 to 20 parts by mass, more preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the base polymer.

Acetylene alcohols can also be blended with the resist material of the present invention. Examples of the acetylene alcohols include those described in paragraphs [0179] to [0182] of JP-A-2008-122932. In the resist material of the present invention, the content of acetylene alcohols is preferably 0 to 5 parts by mass with respect to 100 parts by mass of the base polymer.

[Pattern formation method]
When the resist material of the present invention is used for manufacturing various integrated circuits, known lithography techniques can be applied.

For example, the positive resist material of the present invention can be used as a substrate for manufacturing integrated circuits (Si, SiO ₂ , SiN, SiON, TiN, WSI, BPSG, SOG, organic antireflection film, etc.) or a substrate for manufacturing mask circuits (Cr). , CrO, CrON, MoSi ₂ , SiO _2, etc.) with a coating film thickness of 0.01 to 2.0 μm by an appropriate coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, doctor coating, etc. Apply so that This is prebaked on a hot plate at preferably 60 to 150 ° C. for 10 seconds to 30 minutes, more preferably 80 to 120 ° C. for 30 seconds to 20 minutes. Next, the target pattern is directly exposed through a predetermined mask with high-energy rays such as ultraviolet rays, far ultraviolet rays, EB, EUV, X-rays, soft X-rays, excimer laser, γ-rays, and synchrotron radiation. The exposure dose, 1 to 200 mJ / cm ² or so, in particular 10 to 100 mJ / cm ² or so, or 0.1~100μC / cm ² or so, be exposed to particularly a 0.5~50μC / cm ² of about preferable. Next, PEB is performed on a hot plate at preferably 60 to 150 ° C. for 10 seconds to 30 minutes, more preferably 80 to 120 ° C. for 30 seconds to 20 minutes.

Further, 0.1 to 10% by mass, preferably 2 to 5% by mass of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), tetrabutylammonium hydroxide (TMAH). Develop with a developer of an alkaline aqueous solution such as TBAH) for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes by a conventional method such as a dip method, a puddle method, or a spray method. As a result, the portion irradiated with light is dissolved in the developing solution, the portion not exposed is not dissolved, and a desired positive pattern is formed on the substrate. In the case of negative resist, it is the opposite of the case of positive resist, that is, the portion irradiated with light is insoluble in the developing solution, and the portion not exposed is dissolved. The resist material of the present invention is particularly suitable for fine patterning by KrF excimer laser, ArF excimer laser, EB, EUV, X-ray, soft X-ray, γ-ray, and synchrotron radiation among high-energy rays.

Negative development to obtain a negative pattern by organic solvent development can also be performed using a positive resist material containing a base polymer containing an acid unstable group. The developing solution used at this time is 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutylketone, methylcyclohexanone, acetphenone, methylacetphenone, propyl acetate. , Butyl acetate, Isobutyl acetate, Pentyl acetate, Butenyl acetate, Isopentyl acetate, propyl formate, Butyl formate, Isobutyl formate, Pentyl formate, Isopentyl formate, Methyl valerate, Methyl pentate, Methyl crotonate, Ethyl propionate, Methyl propionate , Ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, pentyl lactate, isopentyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate , Ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, 2-phenylethyl acetate and the like. These organic solvents can be used alone or in admixture of two or more.

Rinse at the end of development. As the rinsing solution, a solvent that is miscible with the developing solution and does not dissolve the resist film is preferable. As such a solvent, an alcohol having 3 to 10 carbon atoms, an ether compound having 8 to 12 carbon atoms, an alkane having 6 to 12 carbon atoms, an alkene, an alkyne, and an aromatic solvent are preferably used.

Specifically, the alcohols having 3 to 10 carbon atoms include n-propyl alcohol, isopropyl alcohol, 1-butyl alcohol, 2-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, and the like. 3-Pentanol, tert-pentyl alcohol, neopentyl alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol , 3-Hexanol, 2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-ethyl-1-butanol, 2-methyl-1-pen Tanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl Examples thereof include -1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, 1-octanol and the like.

Examples of the ether compound having 8 to 12 carbon atoms include di-n-butyl ether, diisobutyl ether, di-sec-butyl ether, di-n-pentyl ether, diisopentyl ether, di-sec-pentyl ether, and di-tert-pentyl. Examples thereof include one or more solvents selected from ether and di-n-hexyl ether.

Examples of alkanes having 6 to 12 carbon atoms include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, cyclononane and the like. Be done. Examples of the alkene having 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, cyclooctene and the like. Examples of the alkyne having 6 to 12 carbon atoms include hexyne, heptyne, octyne and the like.

Examples of the aromatic solvent include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, mesitylene and the like.

By rinsing, it is possible to reduce the occurrence of the resist pattern collapse and defects. In addition, rinsing is not always essential, and the amount of solvent used can be reduced by not rinsing.

It is also possible to shrink the developed hole pattern or trench pattern by thermal flow, RELACS technology or DSA technology. A shrink agent is applied onto the hole pattern, and the diffusion of the acid catalyst from the resist layer during baking causes cross-linking of the shrink agent on the surface of the resist, and the shrink agent adheres to the side wall of the hole pattern. The bake temperature is preferably 70 to 180 ° C., more preferably 80 to 170 ° C., and the time is preferably 10 to 300 seconds, removing excess shrink agent and reducing the hole pattern.

Hereinafter, the present invention will be specifically described with reference to Synthesis Examples, Examples and Comparative Examples, but the present invention is not limited to the following Examples.

The structures of the acid generators PAG1 to PAG21 used in the resist material are shown below. PAG1 to PAG21 were synthesized by ion exchange between an ammonium salt of an iodinated benzene ring-containing fluorosulfonic acid giving the following anion and sulfonium chloride or iodonium chloride giving the following cation, respectively.

[Synthesis Example] Synthesis of Base Polymers (Polymers 1-9, Comparative Polymers 1 and 2) After combining each monomer and performing a copolymerization reaction in a THF solvent, crystallizing in methanol and repeating washing with hexane, it is simply used. It was separated and dried to obtain a base polymer (polymers 1 to 9, comparative polymers 1 and 2) having the composition shown below. The composition of the obtained base polymer ^{was confirmed by 1} H-NMR, and the Mw and dispersity (Mw / Mn) were confirmed by GPC (solvent: THF, standard: polystyrene).

[Examples, comparative examples]
A solution prepared by dissolving each component in a solvent containing 100 ppm of 3M FC-4430 as a surfactant with the compositions shown in Tables 1 and 2 is filtered through a 0.2 μm size filter to prepare a resist material. did.

In Tables 1 and 2, each component is as follows.
Organic solvent: PGMEA (propylene glycol monomethyl ether acetate)
GBL (γ-butyrolactone)
CyH (cyclohexanone)
PGME (Propylene Glycol Monomethyl Ether)
DAA (diacetone alcohol)

Comparative acid generators: Comparative PAGs 1 and 2 (see structural formula below)

Quenchers 1 and 2 (see structural formula below)

[EUV exposure evaluation]
[Examples 1-29, Comparative Examples 1-4]
Each resist material shown in Tables 1 and 2 is spin-coated on a Si substrate formed by Shin-Etsu Chemical Co., Ltd. silicon-containing spin-on hard mask SHB-A940 (silicon content is 43% by mass) with a film thickness of 20 nm. , A resist film having a film thickness of 60 nm was prepared by prebaking at 105 ° C. for 60 seconds using a hot plate. This was exposed using ASML's EUV scanner NXE3300 (NA0.33, σ0.9 / 0.6, quadrupole illumination, wafer top dimension pitch 46 nm, + 20% bias hole pattern mask) and placed on a hot plate. PEB was carried out at the temperatures shown in Tables 1 and 2 for 60 seconds, and development was carried out with a 2.38 mass% TMAH aqueous solution for 30 seconds. Examples 1 to 28 and Comparative Examples 1 to 3 were positive resist patterns (holes having a size of 23 nm). In Example 29 and Comparative Example 4, a negative resist pattern (dot pattern having a size of 23 nm) was formed.
Using a length measuring SEM (CG5000) manufactured by Hitachi High-Technologies Corporation, the exposure amount when holes or dots are formed at 23 nm is measured and used as the sensitivity, and 50 holes or dots at this time are used. CDU (dimension variation 3σ) was determined by measuring the dimensions of.
The results are shown in Tables 1 and 2.

From the results shown in Tables 1 and 2, the resist material of the present invention containing the polymer containing an iodine atom and the onium salt of fluorosulfonic acid containing an iodinated benzene ring as an acid generator has high sensitivity and good CDU. I understood it.

Claims (17)

A resist material containing a base polymer containing a polymer containing an iodine atom and an acid generator containing a sulfonium salt and / or an iodonium salt of an iodinated benzene ring-containing fluorosulfonic acid. Claim 1 in which the sulfonium salt and the iodonium salt of the iodinated benzene ring-containing fluorosulfonic acid are the sulfonium salt represented by the following formula (A-1) and the iodonium salt represented by the following formula (A-2), respectively. The resist material described.

(In the formula, L ¹ is an alkylene group having 1 to 6 carbon atoms which may contain a single bond, an ether bond or an ester bond, or an ether bond or an ester bond.
R ¹ contains a hydroxy group, a carboxy group, a fluorine atom, a chlorine atom, a bromine atom or an amino group, or a fluorine atom, a chlorine atom, a bromine atom, a hydroxy group, an amino group or an alkoxy group having 1 to 10 carbon atoms. May be an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxycarbonyl group having 2 to 10 carbon atoms, an acyloxy group having 2 to 20 carbon atoms, or an alkylsulfonyloxy group having 1 to 20 carbon atoms. , Or -NR ^8- C (= O) -R ⁹ or -NR ^8- C (= O) -O-R ⁹ , where R ⁸ is a hydrogen atom or halogen atom, hydroxy group, 1 to 1 carbon atoms. An alkyl group having 1 to 6 carbon atoms which may contain an alkoxy group of 6 and an acyl group having 2 to 6 carbon atoms or an acyloxy group having 2 to 6 carbon atoms, and R ⁹ is an alkyl having 1 to 16 carbon atoms. A group, an alkenyl group having 2 to 16 carbon atoms, or an aryl group having 6 to 12 carbon atoms, which is a halogen atom, a hydroxy group, an alkoxy group having 1 to 6 carbon atoms, an acyl group having 2 to 6 carbon atoms, or a carbon number of carbon atoms. It may contain 2 to 6 acyloxy groups.
R ² is a single bond or a divalent linking group having 1 to 20 carbon atoms when p is 1, and a trivalent or tetravalent linking group having 1 to 20 carbon atoms when p is 2 or 3. Yes, the linking group may contain an oxygen atom, a sulfur atom or a nitrogen atom.
Rf ^{1 to Rf 4} are independently hydrogen atoms, fluorine atoms or trifluoromethyl groups, but at least one of them is a fluorine atom or trifluoromethyl group. Further, Rf ¹ and Rf ² may be combined to form a carbonyl group.
R ³ , R ⁴ , R ⁵ , R ⁶ and R ⁷ are monovalent hydrocarbon groups having 1 to 20 carbon atoms, which may independently contain heteroatoms. Further, ^{any two of R 3} , R ⁴ and R ⁵ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.
p is an integer that satisfies 1 ≦ p ≦ 3. q and r are integers that satisfy 1 ≦ q ≦ 5, 0 ≦ r ≦ 3, and 1 ≦ q + r ≦ 5. ) The resist material according to claim 1 or 2, wherein the polymer containing an iodine atom contains a repeating unit represented by the following formula (a1) or (a2).

(In the formula, ^RA is a hydrogen atom or a methyl group independently. R ²¹ is a single bond or a methylene group. R ²² is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. .X ¹ represents a single bond, an ether bond, an ester bond, an amide bond, -C (= O) -O- R 23 -, a phenylene group, -Ph-C (= O) -O-R 24 -, or - ^{Ph-R 25 -O-C (} = O) -R 26 - is it, Ph is a phenylene group .R ²³ is an alkylene group having 1 to 10 carbon atoms, contain an ether bond or an ester bond R ²⁴ , R ²⁵ and R ²⁶ are independently single-bonded or linear or branched alkylene groups having 1 to 6 carbon atoms. M and n are 1 ≦ m ≦ 5, respectively. It is an integer that satisfies 0 ≦ n ≦ 4 and 1 ≦ m + n ≦ 5.) The resist material according to claim 3, wherein n is an integer of 1 to 3. The resist material according to any one of claims 1 to 4, further comprising an organic solvent. The resist material according to any one of claims 1 to 5, wherein the polymer containing an iodine atom further contains a repeating unit represented by the following formula (b1) or a repeating unit represented by the following formula (b2).

(In the formula, ^RA is independently a hydrogen atom or a methyl group. Y ¹ is a single bond, a phenylene group or a naphthylene group, or a linking group having 1 to 12 carbon atoms including an ester bond or a lactone ring. Y ² is a single bond or an ester bond. R ³¹ and R ³² are independently acid unstable groups. R ³³ is a hydrogen atom, a trifluoromethyl group, a cyano group, and 1 carbon number. ^{R 34} is an alkyl group of ~ 6, an alkoxy group having 1 to 6 carbon atoms, an acyl group having 2 to 7 carbon atoms, an acyloxy group having 2 to 7 carbon atoms, or an alkoxycarbonyl group having 2 to 7 carbon atoms. It is a single bond or an alkylene group having 1 to 6 carbon atoms, and a part of its carbon atom may be substituted with an ether bond or an ester bond. T is 1 or 2 and s is an integer of 0 to 4. There is, but 1 ≦ t + s ≦ 5.) The resist material according to claim 6, further comprising a dissolution inhibitor. The resist material according to claim 6 or 7, which is a chemically amplified positive resist material. The resist material according to any one of claims 1 to 4, wherein the polymer containing an iodine atom does not contain an acid unstable group. The resist material according to claim 9, further comprising a cross-linking agent. The resist material according to claim 9 or 10, which is a chemically amplified negative resist material. The resist material according to any one of claims 1 to 11, further comprising a quencher. The resist material according to any one of claims 1 to 12, further comprising a surfactant. The resist material according to any one of claims 1 to 13, wherein the polymer containing an iodine atom further contains at least one selected from repeating units represented by the following formulas (g1) to (g3).

(In the formula, ^RA is a hydrogen atom or a methyl group, respectively.
Z ¹ is a single bond, a phenylene group, -O-Z ¹² -, or ^{-C (= O) -Z 11 -Z} 12 - a and, Z ¹¹ is -O- or -NH-, Z ¹² Is an alkylene group having 1 to 6 carbon atoms, an alkenylene group having 2 to 6 carbon atoms, or a phenylene group, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group.
Z ² is a single ^{bond, -Z 21 -C (= O)} -O -, - Z 21 -O- or ^{-Z 21 -O-C (= O} ) - and is, Z ²¹ is 1 to carbon atoms It is 12 alkylene groups and may contain a carbonyl group, an ester bond or an ether bond.
A is a hydrogen atom or a trifluoromethyl group.
Z ³ is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, -O-Z ^32- or -C (= O) -Z ^31- Z ^32- , and Z ³¹ is -O. -Or -NH-, Z ³² is an alkylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, or an alkenylene group having 2 to 6 carbon atoms. Yes, it may contain a carbonyl group, an ester bond, an ether bond or a hydroxy group.
R ^{41 to} R ⁴⁸ are monovalent hydrocarbon groups having 1 to 20 carbon atoms, which may independently contain heteroatoms. Further, ^{any two of R 43} , R ⁴⁴ and R ⁴⁵ , or any two of R ⁴⁶ , R ⁴⁷ and R ⁴⁸ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.
Q ^- represents a non-nucleophilic opposing ion. ) A step of applying the resist material according to any one of claims 1 to 14 on a substrate and heat-treating it to form a resist film, a step of exposing the resist film with a high energy ray, and a developing solution. A pattern forming method including a step of developing a resist film exposed by using the resist film. The pattern forming method according to claim 15, wherein the high energy ray is an ArF excimer laser having a wavelength of 193 nm or a KrF excimer laser having a wavelength of 248 nm. The pattern forming method according to claim 15, wherein the high energy ray is an electron beam or extreme ultraviolet rays having a wavelength of 3 to 15 nm.