JP2021165824A - Resist material and patterning process - Google Patents

Abstract

To provide a resist material that has high sensitivity and small LWR and CDU independent of whether it is a positive resist material or a negative resist material, and a patterning process using the same.SOLUTION: A resist material contains a base polymer, and a quencher containing an onium salt represented by the formula (A).SELECTED DRAWING: None

Description

The present invention relates to a resist material and a pattern forming method.

With the expansion of the IoT market, higher integration, higher speed, and lower power consumption of LSI are further required, and the miniaturization of pattern rules is rapidly progressing. In particular, logic devices are driving miniaturization. As state-of-the-art miniaturization technology, mass production of 10 nm node devices by double patterning, triple patterning, and quadro patterning of ArF immersion lithography is being carried out, and 7 nm by next-generation extreme ultraviolet (EUV) lithography with a wavelength of 13.5 nm. Test mass production of node devices has begun, and mass production of 5nm node devices, which will be the full-scale application of EUV, is imminent.

EUV lithography can form a line pattern with a line width dimension of 20 nm or less by applying a chemically amplified resist material. However, since the effect of image blurring due to acid diffusion becomes greater, higher acid diffusion control than that of resist materials for ArF lithography is required.

For chemically amplified positive resist materials that undergo a deprotection reaction with an acid and chemically amplified negative resist materials that undergo a cross-linking reaction with an acid by adding an acid generator and generating acid by irradiation with light or electron beam (EB). The addition of the quencher for the purpose of controlling the diffusion of the acid to the unexposed portion and improving the contrast was effective. Therefore, many amine quenchers have been proposed (Patent Document 1).

As miniaturization progresses and the diffraction limit of light is approached, the contrast of light decreases. Due to the decrease in light contrast, the resolution of hole patterns and trench patterns and the decrease in focus margin occur in the positive resist film. Attempts have been made to improve the dissolution contrast of the resist film in order to prevent the effect of the decrease in the resolution of the resist pattern due to the decrease in the contrast of light. As a method for increasing the dissolution contrast, there is a method of decreasing the concentration of amine as the exposure amount increases. This may be done by applying a compound that loses its function as a quencher due to light.

The acid-labile group used in the (meth) acrylate polymer for ArF resist materials undergoes a deprotection reaction by using an acid generator that generates sulfonic acid in which the α-position is replaced with a fluorine atom. , The deprotection reaction does not proceed with an acid generator that generates sulfonic acid or carboxylic acid whose α-position is not substituted with a fluorine atom. When a sulfonium salt or iodonium salt that generates a sulfonic acid in which the α-position is substituted with a fluorine atom is mixed with a sulfonium salt or an iodonium salt that generates a sulfonic acid in which the α-position is not substituted with a fluorine atom, the α-position is a fluorine atom. A sulfonium salt or an iodonium salt in which a sulfonic acid not substituted with is generated causes ion exchange with a sulfonic acid whose α-position is substituted with a fluorine atom. The sulfonic acid whose α-position is substituted with a fluorine atom generated by light reverts to a sulfonium salt or iodonium salt by ion exchange, so that the sulfonium salt or iodonium of a sulfonic acid or carboxylic acid whose α-position is not substituted with a fluorine atom The salt acts as a quencher. Furthermore, sulfonic acids and carboxylic acids whose α-position is not substituted with fluorine atoms, and sulfonium salts and iodonium salts that generate sulfonamides lose their ability as a quencher by photolysis, and therefore also function as a photodegradable quencher. (Patent Document 2).

Along with the miniaturization of patterns, the edge roughness (LWR) of line patterns and the dimensional uniformity (CDU) of hole patterns are regarded as problems. The effects of uneven distribution and aggregation of base polymers and acid generators, and the effects of acid diffusion have been pointed out. Further, the LWR tends to increase as the resist film becomes thinner, and the deterioration of the LWR due to the thinning with the progress of miniaturization has become a serious problem.

The EUV resist material is required to achieve high sensitivity, high resolution, low LWR and low CDU at the same time. When the acid diffusion distance is shortened, the LWR becomes smaller, but the sensitivity becomes lower. For example, lowering the post-exposure bake (PEB) temperature reduces the LWR but lowers the sensitivity. Even if the amount of the quencher added is increased, the LWR becomes smaller, but the sensitivity is lowered. It is necessary to break the trade-off relationship between sensitivity and LWRs and CDUs. In addition, EB is also a high-energy ray like EUV, and there is a trade-off relationship between sensitivity and LWR or CDU.

The energy of EUV is much higher than that of ArF excimer laser light, and the number of photons in EUV exposure is 1/14 that of ArF exposure. The size of the pattern formed by EUV exposure is less than half that of ArF exposure. Therefore, EUV exposure is susceptible to variations in the number of photons. The variation in the number of photons in the synchrotron radiation region of extremely short wavelength is shot noise of a physical phenomenon.

Probability theory (Stochastics) is drawing attention. The effect of shot noise cannot be eliminated, but how to reduce this effect is being discussed. It has been observed that not only the CDU and LWR become large due to the influence of shot noise, but also the hole is blocked with a probability of one in millions. If the hole is blocked, the communication will be poor and the transistor will not operate, which will adversely affect the performance of the entire device. As a method of reducing the influence of shot noise on the resist material side, a method of increasing the absorption of light in the resist film to absorb more photons has been proposed.

Japanese Unexamined Patent Publication No. 2001-19477 Japanese Unexamined Patent Publication No. 2012-121838

In the acid-catalyzed chemically amplified resist material, the development of a quencher capable of reducing LWR and CDU with high sensitivity and the development of a resist material capable of contributing to the reduction of shot noise are desired.

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. And.

As a result of diligent studies to achieve the above object, the present inventor has a hydrocarbyl group substituted with an iodine atom or a bromine atom (however, the aromatic ring substituted with an iodine atom or a bromine atom is not included). By using an onium salt of a sulfonamide (hereinafter, also referred to as an iodinated or brominated aliphatic hydrocarbyl group-containing sulfonamide) as a quencher, the sensitivity is high, the LWR and CDU are small, the contrast is high, and the resolution is improved. We have found that it is possible to obtain a resist material that is excellent and has a wide process margin, and completed the present invention.

［式中、ｍ及びｎは、それぞれ独立に、１〜３の整数である。
Ｘ^BIは、ヨウ素原子又は臭素原子である。
Ｒ^ahは、炭素数１〜２０の(ｎ＋１)価の脂肪族炭化水素基であり、エーテル結合、カルボニル基、エステル結合、アミド結合、スルトン環、ラクタム環、カーボネート基、ヨウ素原子以外のハロゲン原子、炭素数６〜１２のアリール基、ヒドロキシ基及びカルボキシ基から選ばれる少なくとも１種を含んでいてもよい。
Ｘ¹は、単結合、エーテル結合、エステル結合、アミド結合、カルボニル基又はカーボネート基である。
Ｘ²は、単結合又は炭素数１〜２０の(ｍ＋１)価の炭化水素基であり、エーテル結合、カルボニル基、エステル結合、アミド結合、スルトン環、ラクタム環、カーボネート基、ヨウ素原子以外のハロゲン原子、ヒドロキシ基及びカルボキシ基から選ばれる少なくとも１種を含んでいてもよい。
Ｘ³は、単結合又はカルボニル基である。
Ｌは、単結合、−Ｏ−、−Ｏ−Ｃ(＝Ｏ)−又は−ＮＲ−Ｃ(＝Ｏ)−であり、Ｒは、水素原子又は炭素数１〜４のヒドロカルビル基である。
Ｒ¹は、単結合又は炭素数１〜２０の飽和ヒドロカルビレン基であり、エーテル結合、エステル結合若しくはヒドロキシ基を含んでいてもよい。
Ｒ²は、炭素数１〜６の飽和ヒドロカルビル基又は炭素数６〜１０のアリール基であり、その水素原子の一部又は全部がフッ素原子で置換されていてもよい。
Ｍ⁺は、下記式（Ａａ）で表されるスルホニウムカチオン、下記式（Ａｂ）で表されるヨードニウムカチオン又は下記式（Ａｃ）で表されるアンモニウムカチオンである。

（式中、Ｒ^a1〜Ｒ^a3は、それぞれ独立に、ハロゲン原子、又はヘテロ原子を含んでいてもよい炭素数１〜２０のヒドロカルビル基である。また、Ｒ^a1及びＲ^a2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。
Ｒ^a4及びＲ^a5は、それぞれ独立に、ハロゲン原子、又はヘテロ原子を含んでいてもよい炭素数１〜２０のヒドロカルビル基である。
Ｒ^a6〜Ｒ^a9は、それぞれ独立に、水素原子又は炭素数１〜２４のヒドロカルビル基であり、該ヒドロカルビル基は、ハロゲン原子、ヒドロキシ基、カルボキシ基、エーテル結合、エステル結合、チオール基、チオエステル結合、チオノエステル結合、ジチオエステル結合、アミノ基、ニトロ基、スルホン基及びフェロセニル基から選ばれる少なくとも１種を含んでいてもよい。Ｒ^a6とＲ^a7とが、互いに結合してこれらが結合する窒素原子と共に環を形成してもよく、Ｒ^a6とＲ^a7と及びＲ^a8とＲ^a9とが、それぞれ互いに結合してこれらが結合する窒素原子と共にスピロ環を形成してもよく、Ｒ^a8とＲ^a9とが合わさって＝Ｃ(Ｒ^a10)(Ｒ^a11)を形成してもよい。Ｒ^a10及びＲ^a11は、それぞれ独立に、水素原子又は炭素数１〜１６のヒドロカルビル基である。Ｒ^a6とＲ^a10とが、互いに結合してこれらが結合する炭素原子及び窒素原子と共に環を形成してもよく、該環の中に、二重結合、酸素原子、硫黄原子又は窒素原子を含んでいてもよい。）］
２．更に、スルホン酸、イミド酸又はメチド酸を発生する酸発生剤を含む１のレジスト材料。
３．更に、有機溶剤を含む１又は２のレジスト材料。
４．前記ベースポリマーが、下記式（ａ１）で表される繰り返し単位又は下記式（ａ２）で表される繰り返し単位を含むものである１〜３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から選ばれる少なくとも１種を含む炭素数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。
Ｙ³は、単結合、エーテル結合又はエステル結合である。
Ｒ¹¹及びＲ¹²は、それぞれ独立に、酸不安定基である。）
Ｒ¹³は、フッ素原子、トリフルオロメチル基、シアノ基又は炭素数１〜６の飽和ヒドロカルビル基である。
Ｒ¹⁴は、単結合又は炭素数１〜６のアルカンジイル基であり、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。
ａは、１又は２である。ｂは、０〜４の整数である。ただし、１≦ａ＋ｂ≦５である。）
５．化学増幅ポジ型レジスト材料である４のレジスト材料。
６．前記ベースポリマーが、酸不安定基を含まないものである１〜３のいずれかのレジスト材料。
７．化学増幅ネガ型レジスト材料である６のレジスト材料。
８．前記ベースポリマーが、更に、下記式（ｆ１）〜（ｆ３）のいずれかで表される繰り返し単位を含む１〜７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、炭素数１〜６の脂肪族ヒドロカルビレン基、フェニレン基、ナフチレン基若しくはこれらを組み合わせて得られる炭素数７〜１８の基、又は−Ｏ−Ｚ¹¹−、−Ｃ(＝Ｏ)−Ｏ−Ｚ¹¹−若しくは−Ｃ(＝Ｏ)−ＮＨ−Ｚ¹¹−である。Ｚ¹¹は、炭素数１〜６の脂肪族ヒドロカルビレン基、フェニレン基、ナフチレン基又はこれらを組み合わせて得られる炭素数７〜１８の基であり、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)−である。Ｚ²¹は、炭素数１〜１２の飽和ヒドロカルビレン基であり、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。
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−Ｚ³¹−、−Ｃ(＝Ｏ)−Ｏ−Ｚ³¹−又は−Ｃ(＝Ｏ)−ＮＨ−Ｚ³¹−である。Ｚ³¹は、炭素数１〜６の脂肪族ヒドロカルビレン基、フェニレン基、フッ素化フェニレン基、又はトリフルオロメチル基で置換された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。
Ｒ²¹〜Ｒ²⁸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のヒドロカルビル基である。また、Ｒ²³及びＲ²⁴又はＲ²⁶及びＲ²⁷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。
Ｒ^HFは、水素原子又はトリフルオロメチル基である。
Ｍ^-は、非求核性対向イオンである。）
９．更に、界面活性剤を含む１〜８のいずれかのレジスト材料。
１０．１〜９のいずれかのレジスト材料を用いて基板上に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、前記露光したレジスト膜を、現像液を用いて現像する工程とを含むパターン形成方法。
１１．前記高エネルギー線が、波長１９３ｎｍのＡｒＦエキシマレーザー光又は波長２４８ｎｍのＫｒＦエキシマレーザー光である１０のパターン形成方法。
１２．前記高エネルギー線が、ＥＢ又は波長３〜１５ｎｍのＥＵＶである１０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 and a quencher containing an onium salt represented by the following formula (A).

[In the formula, m and n are each independently an integer of 1 to 3.
X ^BI is an iodine atom or a bromine atom.
^Rah is a (n + 1) -valent aliphatic hydrocarbon group having 1 to 20 carbon atoms, and is a halogen atom other than an ether bond, a carbonyl group, an ester bond, an amide bond, a sulton ring, a lactam ring, a carbonate group, and an iodine atom. , At least one selected from an aryl group having 6 to 12 carbon atoms, a hydroxy group and a carboxy group may be contained.
X ¹ is a single bond, an ether bond, an ester bond, an amide bond, a carbonyl group or a carbonate group.
X ² is a single-bonded or (m + 1) -valent hydrocarbon group having 1 to 20 carbon atoms, and is an ether bond, a carbonyl group, an ester bond, an amide bond, a sulton ring, a lactam ring, a carbonate group, or a halogen other than an iodine atom. It may contain at least one selected from an atom, a hydroxy group and a carboxy group.
X ³ is a single bond or a carbonyl group.
L is a single bond, −O−, −OC (= O) − or −NR—C (= O) −, and R is a hydrogen atom or a hydrocarbyl group having 1 to 4 carbon atoms.
R ¹ is a single bond or a saturated hydrocarbylene group having 1 to 20 carbon atoms, and may contain an ether bond, an ester bond or a hydroxy group.
R ² is a saturated hydrocarbyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms, and a part or all of its hydrogen atom may be substituted with a fluorine atom.
M ⁺ is a sulfonium cation represented by the following formula (Aa), an iodonium cation represented by the following formula (Ab), or an ammonium cation represented by the following formula (Ac).

(In the formula, R ^{a1 to} R ^a3 are hydrocarbyl groups having 1 to 20 carbon atoms which may independently contain a halogen atom or a hetero atom. Further, R ^a1 and R ^a2 are bonded to each other. The rings may be formed together with the sulfur atoms to which they are bonded.
R ^a4 and R ^a5 are hydrocarbyl groups having 1 to 20 carbon atoms, which may independently contain a halogen atom or a hetero atom.
R ^{a6 to} R ^a9 are independently hydrogen atoms or hydrocarbyl groups having 1 to 24 carbon atoms, and the hydrocarbyl groups are halogen atoms, hydroxy groups, carboxy groups, ether bonds, ester bonds, thiol groups, and thioester bonds. , Thionoester bond, dithioester bond, amino group, nitro group, sulfone group and at least one selected from ferrocenyl group may be contained. R ^a6 and R ^a7 may be bonded to each other to form a ring together with the nitrogen atom to which they are bonded, and R ^a6 and R ^a7 and R ^a8 and R ^a9 are bonded to each other and these are bonded to each other. A spiro ring may be formed together with the nitrogen atom, or R ^a8 and R ^a9 may be combined to form = C (R ^a10 ) (R ^a11 ). R ^a10 and R ^a11 are independently hydrogen atoms or hydrocarbyl groups having 1 to 16 carbon atoms. R ^a6 and R ^a10 may be bonded to each other to form a ring with a carbon atom and a nitrogen atom to which they are bonded, and the ring contains a double bond, an oxygen atom, a sulfur atom or a nitrogen atom. You may be. )]
2. Further, 1 resist material containing an acid generator that generates sulfonic acid, imic acid or methidoic acid.
3. 3. Further, 1 or 2 resist material containing an organic solvent.
4. The resist material according to any one of 1 to 3, wherein the base polymer contains a repeating unit represented by the following formula (a1) or a repeating unit represented by the following formula (a2).

(In the formula, ^RA is a hydrogen atom or a methyl group, respectively.
Y ¹ is a linking group having 1 to 12 carbon atoms containing at least one selected from a single bond, a phenylene group or a naphthylene group, or an ester bond or a lactone ring.
Y ² is a single bond or an ester bond.
Y ³ is a single bond, an ether bond or an ester bond.
R ¹¹ and R ¹² are independently acid-labile groups. )
R ¹³ is a fluorine atom, a trifluoromethyl group, a cyano group or a saturated hydrocarbyl group having 1 to 6 carbon atoms.
R ¹⁴ is a single bond or an alkanediyl 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.
a is 1 or 2. b is an integer from 0 to 4. However, 1 ≦ a + b ≦ 5. )
5. 4 resist materials which are chemically amplified positive resist materials.
6. The resist material according to any one of 1 to 3, wherein the base polymer does not contain an acid unstable group.
7. 6 resist materials which are chemically amplified negative type resist materials.
8. The resist material according to any one of 1 to 7, wherein the base polymer further contains a repeating unit represented by any of the following formulas (f1) to (f3).

(In the formula, ^RA is a hydrogen atom or a methyl group, respectively.
Z ¹ is a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group or a group having 7 to 18 carbon atoms obtained by combining these or ^{-O-Z 11, -, -} C ^{(= O) -O-Z 11} - or -C (= O) -NH-Z 11 - is. Z ¹¹ is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group or a group having 7 to 18 carbon atoms obtained by combining them, and is a carbonyl group, an ester bond, an ether bond or a hydroxy group. May include.
Z ² is a single ^{bond, -Z 21 -C (= O)} -O -, - Z 21 -O- or ^{-Z 21 -O-C (= O} ) - is. Z ²¹ is a saturated hydrocarbylene group having 1 to 12 carbon atoms and may contain a carbonyl group, an ester bond or an ether bond.
Z ³ is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene ^{group, -O-Z 31 -, -} C (= O) -O-Z 31 - or -C (= O) -NH- Z ³¹ −. Z ³¹ is a phenylene group substituted with an aliphatic hydrocarbylene group, a phenylene group, a fluorinated phenylene group, or a trifluoromethyl group having 1 to 6 carbon atoms, and is a carbonyl group, an ester bond, an ether bond, or a hydroxy group. May include.
R ^{21 to} R ²⁸ are hydrocarbyl groups having 1 to 20 carbon atoms, which may independently contain heteroatoms. Further, R ²³ and R ²⁴ or R ²⁶ and R ²⁷ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.
R ^HF is a hydrogen atom or a trifluoromethyl group.
M ^- is a non-nucleophilic opposing ion. )
9. Further, any of 1 to 8 resist materials containing a surfactant.
A step of forming a resist film on a substrate using any of 110 to 9 resist materials, a step of exposing the resist film with high energy rays, and a step of exposing the exposed resist film with a developing solution. A pattern forming method including a step of developing.
11. 10 pattern forming methods in which the high energy ray is an ArF excimer laser light having a wavelength of 193 nm or a KrF excimer laser light having a wavelength of 248 nm.
12. 10 pattern forming methods in which the high energy rays are EB or EUV having a wavelength of 3 to 15 nm.

Since the sulfonamide containing an iodide or brominated aliphatic hydrocarbyl group absorbs a large amount of EB and EUV, the resist film containing the onium salt represented by the formula (A) generates many secondary electrons in the film by exposure. It is possible to improve the sensitivity. The onium salt anion represented by the formula (A) has a long bond distance with a cation due to a steric disorder in which substituents are attached to both sides of the amide group, and is compared with a sulfonium salt type quencher of a carboxylic acid. Ion exchange with sulfonic acid is likely to occur. That is, the ability as a quencher is high, and a high contrast can be obtained by this.

[Resist material]
The resist material of the present invention comprises a base polymer and a quencher containing an onium salt of an iodinated or brominated aliphatic hydrocarbyl group-containing sulfonamide. The sulfonium salt and iodonium salt are acid generators that generate weak acid iodide or brominated aliphatic hydrocarbyl group-containing sulfonamide by light irradiation, but have the form of strongly basic sulfonium salt and iodonium salt. Therefore, it functions as a quencher. The iodinated or brominated aliphatic hydrocarbyl group-containing sulfonamides are not acidic enough to cause a deprotection reaction of acid-labile groups. Therefore, as will be described later, it is effective to add an acid generator that generates a strong acid such as sulfonic acid, imidic acid or methidoic acid, because it separately causes a deprotection reaction of an acid unstable group. The acid generator that generates sulfonic acid, imidic acid or methidoic acid may be an additive type or a bound type that is bound to the base polymer.

When light irradiation is performed in a state where the sulfonium salt and iodonium salt of the sulfonated or brominated aliphatic hydrocarbyl group-containing sulfonamide and an acid generator for generating a super strong acid perfluoroalkyl sulfonic acid are mixed, iodization or iodination or Brominated aliphatic hydrocarbyl group-containing sulfonic amides and perfluoroalkyl sulfonic acids are generated. Since not all acid generators are decomposed, there are undecomposed acid generators in the vicinity. Here, when a sulfonium salt of an iodide or brominated aliphatic hydrocarbyl group-containing sulfonamide, iodonium salt and perfluoroalkyl sulfonic acid coexist, the perfluoroalkyl sulfonic acid first contains an iodide or brominated aliphatic hydrocarbyl group. Ion exchange with the sulfonium salt and iodonium salt of the sulfonamide produces a perfluoroalkyl sulfonic acid sulfonium salt, and an iodide or brominated aliphatic hydrocarbyl group-containing sulfonamide is released. This is because the perfluoroalkyl sulfonate, which has a higher strength as an acid, is more stable. On the other hand, ion exchange does not occur even if the perfluoroalkyl sulfonic acid sulfonium salt or iodonium salt and the iodideized or brominated aliphatic hydrocarbyl group-containing sulfonamide are present. Similar ion exchange occurs not only in perfluoroalkyl sulfonic acid but also in aryl sulfonic acid, alkyl sulfonic acid, imide acid, methidoic acid, etc., which have higher acid strength than iodinated or brominated aliphatic hydrocarbyl group-containing sulfonamide.

The onium salt of an iodide or brominated aliphatic hydrocarbyl group-containing sulfonamide not only suppresses acid diffusion, but also absorbs EUV highly, which generates secondary electrons, which makes the resist more sensitive and reduces shot noise. It can be reduced. The onium salt of an iodinated or brominated aliphatic hydrocarbyl group-containing sulfonamide has a function as a sensitizer as well as a quencher for controlling acid diffusion.

In order to improve the LWR, it is effective to suppress the aggregation of the polymer and the acid generator, but a more remarkable point is the dispersibility of the quencher. Even if the dispersibility of the acid generator in the resist film is improved, the non-uniform presence of the quencher can cause a decrease in LWR. Even in a sulfonium salt type quencher, introducing a substituent such as an alkyl group into the triphenylsulfonium cation is effective for improving LWR. Furthermore, by introducing a halogen atom into the sulfonium salt type quencher, the hydrophobicity is efficiently increased and the dispersibility is improved. The introduction of bulky halogen atoms such as iodine atoms is effective not only for cations of sulfonium salts but also for anions. The onium salt of the iodinated or brominated aliphatic hydrocarbyl group-containing sulfonamide enhances the dispersibility of the quencher in the resist film and reduces the LWR by introducing an iodine atom into the anion.

The LWR reduction effect of the onium salt of the iodinated or brominated aliphatic hydrocarbyl group-containing sulfonamide is effective in both positive pattern formation and negative pattern formation by alkaline development and negative pattern formation in organic solvent development.

[Iodinated or brominated aliphatic hydrocarbyl group-containing sulfonamide onium salt]
The onium salt of the iodinated or brominated aliphatic hydrocarbyl group-containing sulfonamide contained in the resist material of the present invention is a compound represented by the following formula (A).

In the formula (A), m and n are each independently an integer of 1 to 3.

In formula (A), X ^BI is an iodine atom or a bromine atom.

In the formula (A), ^Rah is a (n + 1) -valent aliphatic hydrocarbon group having 1 to 20 carbon atoms, and has an ether bond, a carbonyl group, an ester bond, an amide bond, a sulton ring, a lactam ring, and a carbonate group. It may contain at least one selected from a halogen atom other than the iodine atom, an aryl group having 6 to 12 carbon atoms, a hydroxy group and a carboxy group.

The aliphatic hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include a methanediyl group, an ethane-1,1-diyl group, an ethane-1,2-diyl group, a propane-1,1-diyl group, a propane-1,2-diyl group, and a propane-1,3. -Diyl group, propane-2,2-diyl group, butane-1,1-diyl group, butane-1,2-diyl group, butane-1,3-diyl group, butane-2,3-diyl group, butane -1,4-diyl group, 1,1-dimethylethane-1,2-diyl group, pentane-1,5-diyl group, 2-methylbutane-1,2-diyl group, hexane-1,6-diyl group , Heptane-1,7-diyl group, octane-1,8-diyl group, nonan-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1, Alkanediyl group such as 12-diyl group; cyclopropane-1,1-diyl group, cyclopropane-1,2-diyl group, cyclobutane-1,1-diyl group, cyclobutane-1,2-diyl group, cyclobutane- 1,3-diyl group, cyclopentane-1,1-diyl group, cyclopentane-1,2-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1,1-diyl group, cyclohexane-1, Cycloalkanediyl groups such as 2-diyl group, cyclohexane-1,3-diyl group, cyclohexane-1,4-diyl group; polycycles such as norbornan-2,3-diyl group and norbornan-2,6-diyl group Formula Saturated hydrocarbylene group; alkanediyl group such as 2-propene-1,1-diyl group; alkanediyl group such as 2-propin-1,1-diyl group; 2-cyclohexene-1,2-diyl group, 2- Cycloalkendyl group such as cyclohexene-1,3-diyl group, 3-cyclohexene-1,2-diyl group; polycyclic unsaturated hydrocarbylene group such as 5-norbornene-2,3-diyl group; cyclopentylmethane Cyclic aliphatic hydrocarbylene groups such as diyl group, cyclohexylmethanediyl group, 2-cyclopentenylmethanediyl group, 3-cyclopentenylmethanediyl group, 2-cyclohexenylmethanediyl group, 3-cyclohexenylmethanediyl group. Substituted alkanediyl group; aliphatic hydrocarbylene group such as a group obtained by combining these; tri- or tetravalent obtained by removing one or two hydrogen atoms from the aliphatic hydrocarbylene group. The basis of.

Examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, a tolyl group, a xsilyl group, a 1-naphthyl group, a 2-naphthyl group and the like.

In formula (A), X ¹ is a single bond, an ether bond, an ester bond, an amide bond, a carbonyl group or a carbonate group.

In the formula (A), X ² is a single bond or a (m + 1) valent hydrocarbon group having 1 to 20 carbon atoms, and is an ether bond, a carbonyl group, an ester bond, an amide bond, a sulton ring, a lactam ring, or a carbonate group. , At least one selected from halogen atoms other than iodine atoms, hydroxy groups and carboxy groups may be contained.

The ^{(m + 1) -valent hydrocarbon group represented by X 2} is a group obtained by desorbing (m + 1) hydrogen atoms from the hydrocarbon. The hydrocarbon may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkanes such as methane, ethane, propane, butane, 2-methylpropane, pentane, 2-methylbutane, hexane, heptane, octane, nonane, decane, undecane, and dodecane; cyclopropane, cyclobutane, cyclopentane, and the like. Cyclic saturated hydrocarbons such as cyclohexane, norbornan and adamantan; alkanes such as ethylene, propene, 1-butene, 2-butene and 2-methylpropene; cyclic unsaturated hydrocarbons such as cyclohexene and norbornene; benzene, naphthalene and toluene , Xylene, anthracene and other aromatic hydrocarbons; examples thereof include compounds in which some or all of these groups have their hydrogen atoms substituted with hydrocarbyl groups.

In formula (A), X ³ is a single bond or a carbonyl group.

In the formula (A), L is a single bond, −O−, −OC (= O) − or −NR—C (= O) −, and R is a hydrogen atom or 1 to 4 carbon atoms. It is a hydrocarbyl group.

In the formula (A), R ¹ is a single bond or a saturated hydrocarbylene group having 1 to 20 carbon atoms, and may contain an ether bond, an ester bond or a hydroxy group. The saturated hydrocarbylene group may be linear, branched, or cyclic, and specific examples thereof include a methanediyl group, an ethane-1,1-diyl group, an ethane-1,2-diyl group, and a propane-. 1,1-diyl group, propane-1,2-diyl group, propane-1,3-diyl group, propane-2,2-diyl group, butane-1,1-diyl group, butane-1,2-diyl group Group, butane-1,3-diyl group, butane-2,3-diyl group, butane-1,4-diyl group, 1,1-dimethylethane-1,2-diyl group, pentane-1,5-diyl Group, 2-methylbutane-1,2-diyl group, hexane-1,6-diyl group, heptan-1,7-diyl group, octane-1,8-diyl group, nonan-1,9-diyl group, decane Alkanediyl groups such as -1,10-diyl group, undecane-1,11-diyl group, dodecane-1,12-diyl group; cyclopropane-1,1-diyl group, cyclopropane-1,2-diyl group , Cyclobutane-1,1-diyl group, cyclobutane-1,2-diyl group, cyclobutane-1,3-diyl group, cyclopentane-1,1-diyl group, cyclopentane-1,2-diyl group, cyclopentane Cycloalkanediyl groups such as -1,3-diyl group, cyclohexane-1,1-diyl group, cyclohexane-1,2-diyl group, cyclohexane-1,3-diyl group, cyclohexane-1,4-diyl group; Examples thereof include a polycyclic saturated hydrocarbylene group such as a norbornan-2,3-diyl group and a norbornan-2,6-diyl group.

In the formula (A), R ² is a saturated hydrocarbyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms, and a part or all of its hydrogen atom may be substituted with a fluorine atom. The saturated hydrocarbyl group may be linear, branched or cyclic, and specific examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group and a sec-butyl group. Alkyl groups having 1 to 6 carbon atoms such as groups, tert-butyl groups, n-pentyl groups and n-hexyl groups; cyclic saturation of 3 to 6 carbon atoms such as cyclopropyl groups, cyclobutyl groups, cyclopentyl groups and cyclohexyl groups. Hydrocarbyl groups can be mentioned. Examples of the aryl group include a phenyl group, a methylphenyl group, a dimethylphenyl group, a trimethylphenyl group, an ethylfephenyl group, a diethylphenyl group, an n-propylphenyl group, an isopropylphenyl group, an n-butylphenyl group and an isobutylphenyl group. Examples thereof include sec-butylphenyl group, tert-butylphenyl group, 1-naphthyl group, 2-naphthyl group and the like.

In the formula (A), M ⁺ is a sulfonium cation represented by the following formula (Aa), an iodonium cation represented by the following formula (Ab), or an ammonium cation represented by the following formula (Ac).

Wherein (Aa), R ^a1 ~R ^a3 are each independently a hydrocarbyl group having a halogen atom, or carbon atoms which may contain a hetero atom having 1 to 20. In the formula (Ab), R ^a4 and R ^a5 are hydrocarbyl groups having 1 to 20 carbon atoms which may independently contain a halogen atom or a hetero atom.

Examples of the halogen atom represented by R ^{a1 to} R ^a5 include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like.

The hydrocarbyl groups having 1 to 20 carbon atoms represented by R ^{a1 to} R ^a5 may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group and n-. Alkyl groups having 1 to 20 carbon atoms such as octyl group, n-nonyl group, n-decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, heptadecyl group, octadecyl group, nonadecil group and icosyl group; Cyclic saturated hydrocarbyl group having 3 to 20 carbon atoms such as cyclopropyl group, cyclopentyl group, cyclohexyl group, cyclopropylmethyl group, 4-methylcyclohexyl group, cyclohexylmethyl group, norbornyl group, adamantyl group; vinyl group, propenyl group, Alkenyl groups such as butenyl group and hexenyl group; alkynyl groups having 2 to 20 carbon atoms such as ethynyl group, propynyl group and butyl group; cyclic unsaturated aliphatic hydrocarbyl having 3 to 20 carbon atoms such as cyclohexenyl group and norbornenyl group. Group; phenyl group, methylphenyl group, ethylphenyl group, n-propylphenyl group, isopropylphenyl group, n-butylphenyl group, isobutylphenyl group, sec-butylphenyl group, tert-butylphenyl group, naphthyl group, methylnaphthyl Group, ethylnaphthyl group, n-propylnaphthyl group, isopropylnaphthyl group, n-butylnaphthyl group, isobutylnaphthyl group, sec-butylnaphthyl group, tert-butylnaphthyl group and other aryl groups having 6 to 20 carbon atoms; benzyl group , An aralkyl group having 7 to 20 carbon atoms such as a phenethyl group; a group obtained by combining these groups and the like can be mentioned.

Further, a part or all of the hydrogen atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atom, sulfur atom, nitrogen atom and halogen atom, and a part of carbon atoms of these groups may be substituted. , Oxygen atom, sulfur atom, nitrogen atom and the like may be substituted with a hetero atom-containing group, and as a result, a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate group, a lactone. It may contain a ring, a sulton ring, a carboxylic acid anhydride, a haloalkyl group and the like.

（式中、破線は、Ｒ^a3との結合手である。） Further, R ^a1 and R ^a2 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. At this time, the ring preferably has the structure shown below.

(In the formula, the broken line is the bond with ^Ra3.)

In the formula (Ac), R ^{a6 to} R ^a9 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 24 carbon atoms, and the hydrocarbyl group is a halogen atom, a hydroxy group, a carboxy group, an ether bond or an ester bond. , A thiol group, a thioester bond, a thionoester bond, a dithioester bond, an amino group, a nitro group, a sulfone group and a ferrocenyl group. The hydrocarbyl groups having 1 to 24 carbon atoms represented by R ^{a6 to} R ^a9 may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group and n-. Alkyl groups having 1 to 24 carbon atoms such as octyl group, n-nonyl group, n-decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, heptadecyl group, octadecyl group, nonadecil group and icosyl group; Cyclic saturated hydrocarbyl group having 3 to 24 carbon atoms such as cyclopropyl group, cyclopentyl group, cyclohexyl group, cyclopropylmethyl group, 4-methylcyclohexyl group, cyclohexylmethyl group, norbornyl group, adamantyl group; vinyl group, propenyl group, An alkenyl group having 2 to 24 carbon atoms such as a butenyl group and a hexenyl group; an alkynyl group having 2 to 24 carbon atoms such as an ethynyl group, a propynyl group, a butyl group, a 2-cyclohexylethynyl group and a 2-phenylethynyl group; a cyclohexenyl group. , Norbornenyl group and other cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 24 carbon atoms; phenyl group, methylphenyl group, ethylphenyl group, n-propylphenyl group, isopropylphenyl group, n-butylphenyl group, isobutylphenyl group. , Se-butylphenyl group, tert-butylphenyl group, naphthyl group, methylnaphthyl group, ethylnaphthyl group, n-propylnaphthyl group, isopropylnaphthyl group, n-butylnaphthyl group, isobutylnaphthyl group, sec-butylnaphthyl group, Examples thereof include an aryl group having 6 to 24 carbon atoms such as a tert-butylnaphthyl group; an aralkyl group having 7 to 24 carbon atoms such as a benzyl group and a phenethyl group; and a group obtained by combining these.

Further, R ^a6 and R ^a7 may be bonded to each other to form a ring together with the nitrogen atom to which they are bonded, and R ^a6 and R ^a7 and R ^a8 and R ^a9 may be bonded to each other to form a ring. A spiro ring may be formed together with the nitrogen atom to which R ^a8 is bonded, or R a8 and R ^a9 may be combined to form = C (R ^a10 ) (R ^a11 ). R ^a10 and R ^a11 are independently hydrogen atoms or hydrocarbyl groups having 1 to 16 carbon atoms. Examples of the hydrocarbyl groups, among those exemplified as hydrocarbyl group represented by R ^a6 to R ^a9, are those having 1 to 16 carbon atoms. R ^a6 and R ^a10 may be bonded to each other to form a ring with a carbon atom and a nitrogen atom to which they are bonded, and the ring contains a double bond, an oxygen atom, a sulfur atom or a nitrogen atom. You may be.

Examples of the onium salt anion represented by the formula (A) include, but are not limited to, those shown below.

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

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

Examples of the ammonium cation represented by the formula (Ac) include, but are not limited to, those shown below.

Examples of the method for synthesizing the onium salt represented by the formula (A) include a method of ion-exchange with an onium salt having a weaker acid than an iodinated or brominated aliphatic hydrocarbyl group-containing sulfonamide. Examples of the acid weaker than the iodinated or brominated aliphatic hydrocarbyl group-containing sulfonamide include hydrochloric acid and carbonic acid. When the onium salt is a sulfonium salt or an iodonium salt, an iodide or brominated aliphatic hydrocarbyl group-containing sulfonamide, a sodium salt or an ammonium salt thereof is synthesized by ion exchange with a sulfonium chloride or an iodonium chloride. You can also do it. When the onium salt is a quaternary ammonium salt, the onium salt is neutralized by a neutralization reaction between an iodide or brominated aliphatic hydrocarbyl group-containing sulfonamide and a quaternary ammonium hydroxide containing a desired cation. When is a primary to primary ammonium salt, it can also be synthesized by a neutralization reaction between an iodide or brominated aliphatic hydrocarbyl group-containing sulfonamide and a primary to primary amine giving the desired cation.

In the resist material of the present invention, the content of the onium salt represented by the formula (A) is preferably 0.001 to 50 parts by mass with respect to 100 parts by mass of the base polymer described later from the viewpoint of sensitivity and acid diffusion suppressing effect. , 0.01 to 20 parts by mass is more preferable.

[Base polymer]
In the case of a positive resist material, the base polymer contained in the resist material of the present invention contains a repeating unit containing an acid unstable group. The repeating unit containing an acid unstable group 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 formula (a2) (hereinafter, also referred to as a repeating unit a2). ) Is preferable.

In formulas (a1) and (a2), ^RA is independently a hydrogen atom or a methyl group. Y ¹ is a linking group having 1 to 12 carbon atoms containing at least one selected from a single bond, a phenylene group or a naphthylene group, or an ester bond and a lactone ring. Y ² is a single bond or an ester bond. Y ³ is a single bond, an ether bond or an ester bond. R ¹¹ and R ¹² are independently acid-labile groups. R ¹³ is a fluorine atom, a trifluoromethyl group, a cyano group or a saturated hydrocarbyl group having 1 to 6 carbon atoms. R ¹⁴ is a single bond or an alkanediyl 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. a is 1 or 2. b is an integer from 0 to 4. However, 1 ≦ a + b ≦ 5.

Examples of the monomer that gives the repeating unit a1 include, but are not limited to, those shown below. In the following formula, ^RA and R ¹¹ are 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 and R ¹² are the same as described above.

Examples of the acid unstable group represented by R ¹¹ and R ¹² include those described in JP-A-2013-80033 and JP-A-2013-83821.

（式中、破線は、結合手である。） Typically, the acid unstable group includes those represented by the following formulas (AL-1) to (AL-3).

(In the formula, the broken line is the bond.)

Wherein (AL-1) and (AL-2), R ^L1 and R ^L2 are each independently a hydrocarbyl group having 1 to 40 carbon atoms, an oxygen atom, a sulfur atom, a nitrogen atom, a hetero such as a fluorine atom It may contain atoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. As the hydrocarbyl group, a saturated hydrocarbyl group having 1 to 40 carbon atoms is preferable, and a saturated hydrocarbyl group having 1 to 20 carbon atoms is more preferable.

In the formula (AL-1), c 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 hydrocarbyl groups having 1 to 20 carbon atoms, and contain heteroatoms such as oxygen atom, sulfur atom, nitrogen atom and fluorine atom. You may be. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. As the hydrocarbyl group, a saturated hydrocarbyl 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 the formula (AL-3), ^RL5 , ^RL6 and ^RL7 are independently hydrocarbyl groups having 1 to 20 carbon atoms and contain heteroatoms such as oxygen atom, sulfur atom, nitrogen atom and fluorine atom. You may be. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. As the hydrocarbyl group, a saturated hydrocarbyl 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 base polymer may contain a repeating unit b containing a phenolic hydroxy group as an adhesive group. Examples of the monomer that gives the repeating unit b include, but are not limited to, those shown below. In the following formula, ^RA is the same as described above.

The base polymer may contain a repeating unit c 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 as other adhesive groups. 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 base polymer may contain a repeating unit d derived from indene, benzofuran, benzothiophene, acenaphtylene, chromone, coumarin, norbornadiene or derivatives thereof. Examples of the monomer that gives the repeating unit d include, but are not limited to, those shown below.

The base polymer may contain a repeating unit e derived from vinylnaphthalene, vinylanthracene, vinylpyrene, methyleneindane, vinylpyridine or vinylcarbazole.

The base polymer may contain a repeating unit f derived from an onium salt containing a polymerizable unsaturated bond. Preferred repeating units f include a repeating unit represented by the following formula (f1) (hereinafter, also referred to as a repeating unit f1) and a repeating unit represented by the following formula (f2) (hereinafter, also referred to as a repeating unit f2). And a repeating unit represented by the following formula (f3) (hereinafter, also referred to as a repeating unit f3) can be mentioned. The repeating units f1 to f3 may be used alone or in combination of two or more.

In the formulas (f1) to (f3), ^RA is the same as described above. Z ¹ is a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group or a group having 7 to 18 carbon atoms obtained by combining these or ^{-O-Z 11, -, -} C ^{(= O) -O-Z 11} - or -C (= O) -NH-Z 11 - is. Z ¹¹ is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group or a group having 7 to 18 carbon atoms obtained by combining them, and is a carbonyl group, an ester bond, an ether bond or a hydroxy group. May include. Z ² is a single ^{bond, -Z 21 -C (= O)} -O -, - Z 21 -O- or ^{-Z 21 -O-C (= O} ) - is. Z ²¹ is a saturated hydrocarbylene group having 1 to 12 carbon atoms and may contain a carbonyl group, an ester bond or an ether bond. Z ³ is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene ^{group, -O-Z 31 -, -} C (= O) -O-Z 31 - or -C (= O) -NH- Z ³¹ −. Z ³¹ is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group,
Alternatively, it is a phenylene group substituted with a trifluoromethyl group and may contain a carbonyl group, an ester bond, an ether bond or a hydroxy group. The ^{aliphatic hydrocarbylene group represented by Z 11} and Z ³¹ may be saturated or unsaturated, and may be linear, branched or cyclic. The ^{saturated hydrocarbylene group represented by Z 21} may be linear, branched or cyclic.

In the formulas (f1) to (f3), R ^{21 to} R ²⁸ are hydrocarbyl groups having 1 to 20 carbon atoms which may independently contain a halogen atom or a hetero atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include the same as those exemplified as hydrocarbyl group represented by R ^a1 to R ^a3 in Formula (Aa). Further, R ²³ and R ²⁴ or R ²⁶ and R ²⁷ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. ^{At this time, examples of the ring include the same ring as that exemplified as a ring in which R a1} and R a ² are bonded and can be formed together with a sulfur atom to which they are bonded in the description of the formula (Aa).

In formula (f2), R ^HF is a hydrogen atom or a trifluoromethyl group.

Wherein (f1), M ^- is a non-nucleophilic counter ion. Examples of the non-nucleophilic counter ion include halide ions such as chloride ion and bromide ion, triflate ion, 1,1,1-trifluoroethanesulfonate ion, fluoroalkylsulfonate ion such as nonafluorobutane sulfonate ion, and the like. Tosylate 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 mesilate ion, butane sulfonate ion, bis Methyl ions such as (trifluoromethylsulfonyl) imide ion, bis (perfluoroethylsulfonyl) imide ion, bis (perfluorobutylsulfonyl) imide ion, tris (trifluoromethylsulfonyl) methide ion, tris (perfluoroethylsulfonyl) methide ion, etc. Can be mentioned.

Further, as the non-nucleophilic opposed ion, a sulfonic acid ion in which the α-position represented by the following formula (f1-1) is replaced with a fluorine atom and the α-position represented by the following formula (f1-2) are further used. Examples thereof include a sulfonic acid ion substituted with a fluorine atom and the β-position substituted with a trifluoromethyl group.

In the formula (f1-1), R ³¹ is a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and may contain an ether bond, an ester bond, a carbonyl group, a lactone ring or a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include those similar to those exemplified as the hydrocarbyl group represented by ^{R 111} in the formula (1A') described later.

In formula (f1-2), R ³² is a hydrogen atom, a hydrocarbyl group having 1 to 30 carbon atoms or a hydrocarbylcarbonyl group having 2 to 30 carbon atoms, and contains an ether bond, an ester bond, a carbonyl group or a lactone ring. You may. The hydrocarbyl moiety of the hydrocarbyl group and the hydrocarbylcarbonyl group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include those similar to those exemplified as the hydrocarbyl group represented by ^{R 111} in the formula (1A') described later.

Examples of the cation of the monomer giving the repeating unit f1 include, but are not limited to, those shown below. In the following formula, ^RA is the same as described above.

Examples of the monomer cation giving the repeating unit f2 or f3 include those similar to those exemplified as the sulfonium cation represented by the formula (Aa).

Examples of the monomer anion that gives the repeating unit f2 include, but are not limited to, those shown below. In the following formula, ^RA is the same as described above.

Examples of the monomer anion that gives the repeating unit f3 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. In addition, LWR and CDU are improved by uniformly dispersing the acid generator. When a base polymer containing a repeating unit f (that is, a polymer bound type acid generator) is used, the formulation of the acid generator described later may be omitted.

The base polymer for positive resist materials requires repeating units a1 or a2 containing acid-labile groups. In this case, the content ratios of the repeating units a1, a2, b, c, d, e and f are 0 ≦ a1 <1.0, 0 ≦ a2 <1.0, 0 <a1 + a2 <1.0, 0 ≦ b. ≦ 0.9, 0 ≦ c ≦ 0.9, 0 ≦ d ≦ 0.8, 0 ≦ e ≦ 0.8 and 0 ≦ f ≦ 0.5 are preferable, and 0 ≦ a1 ≦ 0.9, 0 ≦ a2 ≦ 0.9, 0.1 ≦ a1 + a2 ≦ 0.9, 0 ≦ b ≦ 0.8, 0 ≦ c ≦ 0.8, 0 ≦ d ≦ 0.7, 0 ≦ e ≦ 0.7 and 0 ≦ f ≤0.4 is more preferable, 0≤a1≤0.8, 0≤a2≤0.8, 0.1≤a1 + a2≤0.8, 0≤b≤0.75, 0≤c≤0.75, More preferably, 0 ≦ d ≦ 0.6, 0 ≦ e ≦ 0.6, and 0 ≦ f ≦ 0.3. When the repeating unit f is at least one selected from the repeating units f1 to f3, f = f1 + f2 + f3. Further, a1 + a2 + b + c + d + e + f = 1.0.

On the other hand, the base polymer for negative resist materials does not necessarily require an acid-labile group. Examples of such a base polymer include a repeating unit b and, if necessary, a repeating unit c, d, e and / or f. The content ratio of these repeating units is preferably 0 <b ≦ 1.0, 0 ≦ c ≦ 0.9, 0 ≦ d ≦ 0.8, 0 ≦ e ≦ 0.8, and 0 ≦ f ≦ 0.5. , 0.2 ≦ b ≦ 1.0, 0 ≦ c ≦ 0.8, 0 ≦ d ≦ 0.7, 0 ≦ e ≦ 0.7 and 0 ≦ f ≦ 0.4, more preferably 0.3 ≦ More preferably, b ≦ 1.0, 0 ≦ c ≦ 0.75, 0 ≦ d ≦ 0.6, 0 ≦ e ≦ 0.6 and 0 ≦ f ≦ 0.3. When the repeating unit f is at least one selected from the repeating units f1 to f3, f = f1 + f2 + f3. Further, b + c + d + e + f = 1.0.

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

Examples of the organic solvent used at the time of polymerization include toluene, benzene, tetrahydrofuran (THF), 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-methylpropionate) ), Benzoyl peroxide, lauroyl peroxide and the like. The temperature at the time of polymerization is preferably 50 to 80 ° C. 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 which is easily deprotected with an acid such as an ethoxyethoxy group at the time of polymerization, and deprotection may be carried out 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 remove hydroxystyrene or hydroxyvinyl. It may be naphthalene.

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. The reaction time is preferably 0.2 to 100 hours, more preferably 0.5 to 20 hours.

The base polymer has a polystyrene-equivalent weight average molecular weight (Mw) of preferably 1,000 to 500,000, more preferably 2,000 to 30,000, by gel permeation chromatography (GPC) using THF as a solvent. Is. If Mw is too small, the resist material will be inferior in heat resistance, and if it is too large, the alkali solubility will decrease, and the tailing phenomenon will easily occur after pattern formation.

Further, when the molecular weight distribution (Mw / Mn) of the base polymer is wide, since a polymer having a low molecular weight or a high molecular weight is present, foreign matter may be seen on the pattern or the shape of the pattern may be deteriorated after exposure. There is a risk. As the pattern rule becomes finer, the influence of Mw and Mw / Mn tends to increase. Therefore, in order to obtain a resist material suitable for fine pattern dimensions, Mw / Mn of the base polymer is 1.0. It is preferable that the dispersion is as narrow as ~ 2.0, particularly 1.0 to 1.5.

The base polymer may contain two or more polymers having different composition ratios, Mw, and Mw / Mn. Further, the base polymer may contain a polymer different from the above-mentioned polymer as long as the effect of the present invention is not impaired, but it is preferable not to contain the polymer.

[Acid generator]
The resist material of the present invention may contain an acid generator that generates a strong acid (hereinafter, also referred to as an additive acid generator). The strong acid referred to here is a compound having sufficient acidity to cause a deprotection reaction of the acid unstable group of the base polymer in the case of a positive resist material, and a polarity due to an acid in the case of a negative resist material. It means a compound having sufficient acidity to cause a change reaction or a cross-linking reaction. By containing such an acid generator, the onium salt represented by the formula (A) functions as a quencher, and the resist material of the present invention functions as a chemically amplified positive resist material or a chemically amplified negative resist material. can do. By using a chemically amplified resist material that utilizes an acid-catalyzed reaction, the resist material becomes more sensitive, and various properties become more excellent, which makes it extremely useful. When the base polymer is a polymer bound type acid generator, the additive type acid generator may not be contained.

Examples of the additive-type acid generator include a compound (photoacid generator) that generates a strong acid in response to high energy rays. The photoacid generator may be any compound that generates a strong acid by irradiation with high energy rays, but a compound that generates a sulfonic acid, an imic acid or a methidoic acid is preferable. Suitable photoacid generators include sulfonium salt type, iodonium salt type, sulfonyldiazomethane type, N-sulfonyloxyimide type, oxime-O-sulfonate type and other photoacid generators. Specific examples of the photoacid generator include those described in paragraphs [0122] to [0142] of JP-A-2008-111103.

Further, as the photoacid generator, one represented by the following formula (1) can also be preferably used.

In the formula (1), R ^{101 to} R ¹⁰³ are hydrocarbyl groups having 1 to 20 carbon atoms which may independently contain a halogen atom or a hetero atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include the same as those exemplified as hydrocarbyl group represented by R ^a1 to R ^a3 in Formula (Aa). Further, R ¹⁰¹ and R ¹⁰² may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. ^{At this time, examples of the ring include the same ring as that exemplified as a ring in which R a1} and R a ² are bonded and can be formed together with a sulfur atom to which they are bonded in the description of the formula (Aa).

Examples of the sulfonium salt cation represented by the formula (1) include those similar to those exemplified as the sulfonium cation represented by the formula (Aa).

In the formula (1), X ^- is an anion selected from the following formulas (1A) to (1D).

In formula (1A), R ^fa is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a hetero atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include those similar to those exemplified as the hydrocarbyl group represented by ^{R 111} in the formula (1A') described later.

As the anion represented by the formula (1A), the anion represented by the following formula (1A') is preferable.

In formula (1A'), R ^HF is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. R ¹¹¹ is a hydrocarbyl group having 1 to 38 carbon atoms which may contain a hetero atom. As the hetero atom, an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom and the like are preferable, and an oxygen atom is more preferable. The hydrocarbyl group is particularly preferably one having 6 to 30 carbon atoms from the viewpoint of obtaining high resolution in fine pattern formation.

The ^{hydrocarbyl group represented by R 111} may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, heptyl group and 2-ethylhexyl group. , Nonyl group, undecyl group, tridecyl group, pentadecyl group, heptadecyl group, icosanyl group and other alkyl groups having 1-38 carbon atoms; cyclopentyl group, cyclohexyl group, 1-adamantyl group, 2-adamantyl group, 1-adamantylmethyl group. , Norbornyl group, Norbornylmethyl group, Tricyclodecanyl group, Tetracyclododecanyl group, Tetracyclododecanylmethyl group, Dicyclohexylmethyl group and other cyclic saturated hydrocarbyl groups having 3 to 38 carbon atoms; allyl group, 3 -Unsaturated aliphatic hydrocarbyl group having 2-38 carbon atoms such as cyclohexenyl group; aryl group having 6-38 carbon atoms such as phenyl group, 1-naphthyl group and 2-naphthyl group; benzyl group, diphenylmethyl group and the like. An aralkyl group having 7 to 38 carbon atoms; a group obtained by combining these groups and the like can be mentioned.

Further, a part or all of the hydrogen atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atom, sulfur atom, nitrogen atom and halogen atom, and a part of carbon atoms of these groups may be substituted. , Oxygen atom, sulfur atom, nitrogen atom and the like may be substituted with a hetero atom-containing group, and as a result, a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate group, a lactone. It may contain a ring, a sulton ring, a carboxylic acid anhydride, a haloalkyl group and the like. Hydrocarbyl groups containing heteroatoms include tetrahydrofuryl group, methoxymethyl group, ethoxymethyl group, methylthiomethyl group, acetamidomethyl group, trifluoroethyl group, (2-methoxyethoxy) methyl group, acetoxymethyl group and 2-carboxy. Examples thereof include a -1-cyclohexyl group, a 2-oxopropyl group, a 4-oxo-1-adamantyl group and a 3-oxocyclohexyl group.

Regarding the synthesis of a sulfonium salt containing an anion represented by the formula (1A'), JP-A-2007-145977, JP-A-2008-106045, JP-A-2009-7327, and JP-A-2009-258695 And so on. Further, the sulfonium salts described in JP-A-2010-215608, JP-A-2012-41320, JP-A-2012-106986, JP-A-2012-153644 and the like are also preferably used.

Examples of the anion represented by the formula (1A) include those similar to those exemplified as the anion represented by the formula (1A) of JP-A-2018-197853.

In formula (1B), R ^fb1 and R ^fb2 are hydrocarbyl groups having 1 to 40 carbon atoms which may independently contain a fluorine atom or a hetero atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include those similar to those exemplified as the hydrocarbyl group represented by ^{R 111} in the formula (1A'). The R ^fb1 and R ^fb2 are preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. Further, R ^fb1 and R ^fb2 may be bonded to each other to form a ring together with _{a group (−CF 2} −SO ₂ −N ⁻ −SO ₂ −CF _{2 −) to which they are bonded.} ^The group obtained by bonding fb1 and R ^fb2 to each other is preferably an ethylene fluorinated group or a propylene fluorinated group.

In the formula (1C), R ^fc1 , R ^fc2 and R ^fc3 are hydrocarbyl groups having 1 to 40 carbon atoms which may independently contain a fluorine atom or a hetero atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include those similar to those exemplified as the hydrocarbyl group represented by ^{R 111} in the formula (1A'). R ^fc1 , R ^fc2 and R ^fc3 are preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. Further, R ^fc1 and R ^fc2 may be bonded to each other to form a ring together with _{a group (−CF 2} −SO ₂ −C ⁻ −SO ₂ −CF _{2 −) to which they are bonded.} ^The group obtained by bonding fc1 and R ^fc2 to each other is preferably an ethylene fluorinated group or a propylene fluorinated group.

In formula (1D), R ^fd is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include those similar to those exemplified as the hydrocarbyl group represented by ^{R 111} in the formula (1A').

The synthesis of a sulfonium salt containing an anion represented by the formula (1D) is described in detail in JP-A-2010-215608 and JP-A-2014-133723.

Examples of the anion represented by the formula (1D) include those similar to those exemplified as the anion represented by the formula (1D) of JP-A-2018-197853.

The photoacid generator containing an anion represented by the formula (1D) does not have a fluorine atom at the α-position of the sulfo group, but has two trifluoromethyl groups at the β-position. Due to this, it has sufficient acidity to cleave the acid-labile groups in the base polymer. Therefore, it can be used as a photoacid generator.

Further, as the photoacid generator, one represented by the following formula (2) can also be preferably used.

In the formula (2), R ²⁰¹ and R ²⁰² are hydrocarbyl groups having 1 to 30 carbon atoms which may independently contain a halogen atom or a hetero atom. R ²⁰³ is a hydrocarbylene group having 1 to 30 carbon atoms which may contain a hetero atom. Further, ^{any two of R 201} , R ²⁰² and R ²⁰³ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. ^{At this time, examples of the ring include those similar to those exemplified as a ring in which R a1} and R a ² are bonded to each other and can be formed together with a sulfur atom to which they are bonded in the description of the formula (Aa).

The ^{hydrocarbyl groups represented by R 201} and R ²⁰² may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, tert-pentyl group, n-hexyl group and n-. Alkyl groups having 1 to 30 carbon atoms such as octyl group, 2-ethylhexyl group, n-nonyl group, n-decyl group; cyclopentyl group, cyclohexyl group, cyclopentylmethyl group, cyclopentylethyl group, cyclopentylbutyl group, cyclohexylmethyl group, Cyclic saturated hydrocarbyl group having 3 to 30 carbon atoms such as cyclohexylethyl group, cyclohexylbutyl group, norbornyl group, tricyclo [5.2.1.0 ^2,6 ] decanyl group, adamantyl group; phenyl group, naphthyl group, anthracenyl group An aryl group having 6 to 30 carbon atoms such as a group; a group obtained by combining these groups and the like can be mentioned. Further, a part or all of the hydrogen atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atom, sulfur atom, nitrogen atom and halogen atom, and a part of carbon atoms of these groups may be substituted. , Oxygen atom, sulfur atom, nitrogen atom and the like may be substituted with a hetero atom-containing group, and as a result, a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate group, a lactone. It may contain a ring, a sulton ring, a carboxylic acid anhydride, a haloalkyl group and the like.

The ^{hydrocarbylene group represented by R 203} may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include a methanediyl group, an ethane-1,1-diyl group, an ethane-1,2-diyl group, a propane-1,3-diyl group, a butane-1,4-diyl group, and a pentane-1,5. -Diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonan-1,9-diyl group, decan-1,10-diyl group, undecane -1,11-diyl group, dodecane-1,12-diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16- Alkanediyl group having 1 to 30 carbon atoms such as diyl group and heptadecane-1,17-diyl group; cyclic saturation of 3 to 30 carbon atoms such as cyclopentanediyl group, cyclohexanediyl group, norbornandyl group and adamantandiyl group. Examples thereof include a hydrocarbylene group; an arylene group such as a phenylene group and a naphthylene group; and a group obtained by combining these groups. Further, a part or all of the hydrogen atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atom, sulfur atom, nitrogen atom and halogen atom, and a part of carbon atoms of these groups may be substituted. , Oxygen atom, sulfur atom, nitrogen atom and the like may be substituted with a hetero atom-containing group, and as a result, a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate group, a lactone. It may contain a ring, a sulton ring, a carboxylic acid anhydride, a haloalkyl group and the like. As the hetero atom, an oxygen atom is preferable.

In formula (2), L ¹ is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a single bond, an ether bond, or a hetero atom. The hydrocarbylene group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include those similar to those exemplified as the hydrocarbylene group represented by ^{R 203.}

In formula (2), X ^A , X ^B , X ^C and X ^D are independently hydrogen atoms, fluorine atoms or trifluoromethyl groups. However, ^{at least one of X A} , X ^B , X ^C and X ^D is a fluorine atom or a trifluoromethyl group.

In equation (2), k is an integer from 0 to 3.

As the photoacid generator represented by the formula (2), the one represented by the following formula (2') is preferable.

In equation (2'), L ¹ is the same as described above. R ^HF is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. R ³⁰¹ , R ³⁰² and R ³⁰³ are hydrocarbyl groups having 1 to 20 carbon atoms which may independently contain a hydrogen atom or a hetero atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include those similar to those exemplified as the hydrocarbyl group represented by ^{R 111} in the formula (1A'). x and y are independently integers from 0 to 5, and z is an integer from 0 to 4.

Examples of the photoacid generator represented by the formula (2) include those similar to those exemplified as the photoacid generator represented by the formula (2) of JP-A-2017-026980.

Among the photoacid generators, those containing an anion represented by the formula (1A') or (1D) are particularly preferable because they have low acid diffusion and excellent solubility in a solvent. Further, the one represented by the formula (2') has extremely small acid diffusion and is particularly preferable.

As the photoacid generator, a sulfonium salt or an iodonium salt having an anion containing an aromatic ring substituted with an iodine atom or a bromine atom can also be used. Examples of such a salt include those represented by the following formula (3-1) or (3-2).

In the formulas (3-1) and (3-2), p is an integer satisfying 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.

In formulas (3-1) and (3-2), ^XBI is an iodine atom or a bromine atom, and when p and / or q is 2 or more, they may be the same or different from each other.

In formulas (3-1) and (3-2), L ¹¹ is a saturated hydrocarbylene 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. Is. The saturated hydrocarbylene group may be linear, branched or cyclic.

In formulas (3-1) and (3-2), L ¹² is a single bond or a divalent linking group having 1 to 20 carbon atoms when p is 1, and carbon when p is 2 or 3. It is a (p + 1) -valent linking group of the number 1 to 20, and the linking group may contain an oxygen atom, a sulfur atom or a nitrogen atom.

In formulas (3-1) and (3-2), R ⁴⁰¹ contains a hydroxy group, a carboxy group, a fluorine atom or a chlorine atom, or a fluorine atom, a chlorine atom, a bromine atom, a hydroxy group, an amino group or an ether bond. It may be a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 20 carbon atoms, a saturated hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms, and carbon. Saturated hydrocarbyl carbonyloxy group of number 2 to 20 or saturated hydrocarbyl sulfonyloxy group of number 1 to 20 carbon, or -N (R ^401A ) (R ^401B ), -N (R ^401C ) -C (= O) -R ^401D Alternatively, -N (R ^401C ) -C (= O) ^{-OR 401D} . R ^401A and R ^401B are independently hydrogen atoms or saturated hydrocarbyl groups having 1 to 6 carbon atoms. R ^401C is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms or a saturated hydrocarbyl group having 2 carbon atoms. It may contain ~ 6 saturated hydrocarbylcarbonyloxy groups. R ^401D is an aliphatic hydrocarbyl group having 1 to 16 carbon atoms, an aryl group having 6 to 14 carbon atoms or an aralkyl group having 7 to 15 carbon atoms, and is a halogen atom, a hydroxy group, or a saturated hydrocarbyloxy having 1 to 6 carbon atoms. It may contain a group, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. The aliphatic hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. The saturated hydrocarbyl group, saturated hydrocarbyloxy group, saturated hydrocarbyloxycarbonyl group, saturated hydrocarbylcarbonyl group and saturated hydrocarbylcarbonyloxy group may be linear, branched or cyclic. When p and / or r is 2 or more, each R ⁴⁰¹ may be the same or different from each other.

Of these, R ⁴⁰¹ includes a hydroxy group, -N (R ^401C ) -C (= O) -R ^401D , -N (R ^401C ) -C (= O) ^{-OR 401D} , a fluorine atom, and chlorine. Atoms, bromine atoms, methyl groups, methoxy groups and the like are preferable.

In formulas (3-1) and (3-2), Rf ^{11 to Rf 14} are independently hydrogen atoms, fluorine atoms or trifluoromethyl groups, but at least one of them is a fluorine atom or trifluoromethyl group. It is a fluoromethyl group. Further, Rf ¹¹ and Rf ¹² may be combined to form a carbonyl group. In particular, it is preferable that both ^{Rf 13} and Rf ^{14 are fluorine atoms.}

In formulas (3-1) and (3-2), R ^{402 to} R ⁴⁰⁶ are hydrocarbyl groups having 1 to 20 carbon atoms which may independently contain a halogen atom or a hetero atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include the same as those exemplified as hydrocarbyl group represented by R ^a1 to R ^a5 in the description of formula (Aa) and (Ab). Further, a part or all of the hydrogen atoms of these groups may be substituted with a hydroxy group, a carboxy group, a halogen atom, a cyano group, a nitro group, a mercapto group, a sulton group, a sulfone group or a sulfonium salt-containing group. , Some of the carbon atoms of these groups may be substituted with ether bonds, ester bonds, carbonyl groups, amide bonds, carbonate groups or sulfonic acid ester bonds. Further, R ⁴⁰² and R ⁴⁰³ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. ^{At this time, examples of the ring include those similar to those exemplified as a ring in which R a1} and R a ² are bonded to each other and can be formed together with a sulfur atom to which they are bonded in the description of the formula (Aa).

Examples of the sulfonium salt cation represented by the formula (3-1) include those similar to those exemplified as the sulfonium cation represented by the formula (Aa). Further, examples of the cation of the iodonium salt represented by the formula (3-2) include those similar to those exemplified as the iodonium cation represented by the formula (Ab).

Examples of the onium salt anion represented by the formula (3-1) or (3-2) include, but are not limited to, those shown below. In the following formula, X ^BI is the same as above.

When the resist material of the present invention contains the additive-type acid generator, the content thereof 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.

[Organic solvent]
The resist material of the present invention may contain an organic solvent. The organic solvent is not particularly limited as long as each of the above-mentioned components and each of the following components can be dissolved. Examples of the organic solvent include ketones such as cyclohexanone, cyclopentanone, methyl-2-n-pentyl ketone and 2-heptanone described in paragraphs [0144] to [0145] of JP-A-2008-111103, 3. -Alcohols such as methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, diacetone alcohol, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol mono Ethers such as ethyl ether, ethylene glycol monoethyl ether, 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, Examples thereof include esters such as ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate and propylene glycol monotert-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.

[Other ingredients]
In addition to the above-mentioned components, a surfactant, a dissolution inhibitor, a cross-linking agent, etc. are appropriately combined and blended according to the purpose to form a positive resist material and a negative resist material, whereby the base polymer is formed in the exposed part. However, since the dissolution rate in the developing solution is accelerated by the catalytic reaction, it is possible to obtain an extremely sensitive positive resist material and 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.

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. 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. The surfactant may be used alone or in combination of two or more.

When the resist material of the present invention is of the positive type, the difference in dissolution rate between the exposed portion and the unexposed portion can be further increased by adding a dissolution inhibitor, and the resolution can be further improved. .. 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 is replaced by an unstable group at a ratio of 0 to 100 mol% as a whole, or a compound containing a carboxy group in the molecule, and a hydrogen atom of the carboxy group is replaced by an acid unstable group in an average ratio of 50 to 100 mol% as a whole. 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.

On the other hand, when the resist material of the present invention is a negative type, a negative pattern can be obtained by reducing the dissolution rate of the exposed portion by adding a cross-linking agent. 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 azide 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 alkenyloxy 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.

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 methoxyl groups are acyloxymethylated, or a mixture thereof.

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

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 alkenyloxy group include ethylene glycol divinyl ether, triethylene glycol divinyl ether, 1,2-propanediol divinyl ether, 1,4-butanediol divinyl ether, tetramethylene glycol divinyl ether, and neopentyl glycol divinyl ether. 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 cross-linking agent may be used alone or in combination of two or more.

The resist material of the present invention may contain a quencher other than the onium salt represented by the formula (A) (hereinafter, referred to as another 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 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 other quenchers 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 a sulfonic acid or carboxylic acid 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, as the other quencher, the polymer type quencher described in JP-A-2008-239918 can be mentioned. This enhances the rectangularity of the resist pattern by orienting it on the surface of the resist film. 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.

Other quenchers include an ammonium salt of benzoic acid substituted with an iodine atom described in JP-A-2020-02197298, and an amine compound having an iodinated aromatic group described in JP-A-2020-0227297. , An ammonium salt compound having an iodinated aromatic group described in JP-A-2020-0383558, and a sulfonium salt of benzoic acid substituted with an iodine atom described in JP-A-2017-219836. Since the sensitivity and dimensional uniformity are improved by containing a highly absorbed iodine atom, the quencher of the present invention can be used in combination with these quenchers.

The content of other quenchers in the resist material of the present invention 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. Other quenchers can be used alone or in combination of two or more.

In order to improve the water repellency of the surface of the resist film, the resist material of the present invention may contain a water repellency improver. The water repellency improver can be used for immersion lithography without using a top coat. As the water repellency improving agent, a polymer containing an alkyl fluoride group, a polymer containing a 1,1,1,3,3,3-hexafluoro-2-propanol residue having a specific structure, or the like is preferable, and Japanese Patent Application Laid-Open No. 2007- Those exemplified in JP-A-297590, JP-A-2008-111103 and the like are more preferable. The water repellency improver needs to be dissolved in an alkaline developer or an organic solvent developer. The water repellency improver having the specific 1,1,1,3,3,3-hexafluoro-2-propanol residue described above has good solubility in a developing solution. As a water repellency improving agent, a polymer 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. 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. The water repellency improver may be used alone or in combination of two or more.

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. The content of acetylene alcohols in the resist material of the present invention is preferably 0 to 5 parts by mass with respect to 100 parts by mass of the base polymer. The acetylene alcohols may be used alone or in combination of two or more.

[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, as a pattern forming method, a step of forming a resist film on a substrate using the resist material described above, a step of exposing the resist film with high energy rays, and a step of exposing the exposed resist film with a developing solution are used. Examples thereof include a method including a step of developing.

First, the resist material of the present invention is applied to a substrate for manufacturing an integrated circuit (Si, SiO ₂ , SiN, SiON, TiN, WSi, BPSG, SOG, an organic antireflection film, etc.) or a substrate for manufacturing a mask circuit (Cr, CrO). , CrON, MoSi ₂ , SiO _2, etc.) by an appropriate coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, doctor coating, etc. so that the coating film thickness is 0.01 to 2 μm. do. 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 to form a resist film.
The resist film is then exposed to high energy rays. Examples of the high-energy rays include ultraviolet rays, far ultraviolet rays, EB, EUV, X-rays, soft X-rays, excimer laser light, γ-rays, synchrotron radiation and the like. When ultraviolet rays, far ultraviolet rays, EUV, X-rays, soft X-rays, excimer laser light, γ-rays, synchrotron radiation, etc. are used as the high-energy rays, a mask for directly or forming a desired pattern is used. Irradiation is performed so that the exposure amount is preferably ^{about 1 to 200 mJ / cm 2} , and more preferably about 10 to ^{100 mJ / cm 2.} When using the EB as the high-energy radiation, the exposure amount is preferably 0.1~100μC / cm ^2, more preferably about a mask for forming a pattern of direct or object at about 0.5~50μC / cm ² Draw using. The resist material of the present invention is particularly suitable for fine patterning by KrF excimer laser light, ArF excimer laser light, EB, EUV, X-ray, soft X-ray, γ-ray, and synchrotron radiation, among high-energy rays. , Especially suitable for fine patterning by EB or EUV.

After the exposure, PEB may be carried out on a hot plate or in an oven, preferably at 50 to 150 ° C. for 10 seconds to 30 minutes, more preferably at 60 to 120 ° C. for 30 seconds to 20 minutes.

It is not necessary to perform PEB. In particular, in the case of the anion bound PAG polymer containing the repeating unit f2 or f3, sulfonic acid is generated by exposure and the alkali solubility is improved, so that the exposed portion dissolves in alkali without PEB. If PEB is not performed, the image blur due to acid diffusion disappears, and finer pattern formation can be expected than when PEB is performed.

When PEB is not performed, the deprotection reaction by acid does not occur, so that the resist material of the present invention functions as a non-chemically amplified resist material. In this case, due to the low dissolution contrast, the film of the pattern is reduced and the residual film of the space portion is generated after development. For non-chemically amplified resist materials, the key point is how to improve the dissolution contrast.

In the case of the base polymer containing the repeating unit f2 or f3, α-fluorosulfonic acid is generated by exposure to improve the solubility in an alkaline developing solution, but an onium salt in which the α-position is not fluorinated is added. The generation of α-fluorosulfonic acid is suppressed by salt exchange with this. When the exposure amount is further increased, the alkali solubility is improved by decomposing the onium salt of the sulfonic acid or carboxylic acid whose α-position is not fluorinated. That is, in the region where the exposure amount is small, the dissolution inhibitory property is improved, and in the region where the exposure amount is large, the dissolution promotion property is improved, so that the contrast is improved. Since the rate of the ion exchange reaction is high and proceeds at room temperature, it is not necessary to perform PEB. Since the onium salt represented by the formula (A) is also a salt of a weaker acid than α-fluorosulfonic acid, the same ion exchange occurs, so that the contrast is improved even when PEB is not performed.

After exposure or PEB, 0.1 to 10% by mass, preferably 2 to 5% by mass of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), tetrabutyl Using a developing solution of an alkaline aqueous solution such as ammonium hydroxide (TBAH), the dipping method, the puddle method, the spray method, etc. are usually used for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes. By developing the resist film exposed by the method, a desired pattern is formed. In the case of a positive resist material, 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 the negative resist material, the opposite of the case of the positive resist material, the light-irradiated portion is insoluble in the developing solution, and the unexposed portion is dissolved.

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 crotonate, 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 include 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, heptin, 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.

The developed hole pattern or trench pattern can also be shrunk by thermal flow, RELACS technology or DSA technology. A shrink agent is applied onto the hole pattern, and the acid catalyst diffuses from the resist film during baking to cause cross-linking of the shrink agent on the surface of the resist film, 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 bake 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.

[1] Synthesis of Quencher Sulfonium salts SQ-1 to SQ-12, iodonium salts IQ-1 to IQ-3 and ammonium of iodinated or brominated aliphatic hydrocarbyl group-containing sulfonamides used in the resist material of the present invention. The structures of the salts NQ-1 to NQ-5 are shown below.

[Synthesis Examples 1-1-1-20]
The sulfonium salt SQ-1 reacts trifluoromethanesulfonic acid amide ethanol with 2-iodopropionic acid chloride to synthesize N- [2- (2-iodo-1-ylcarbonyloxy) ethyl] trifluoromethanesulfonamide. , This was synthesized by ion exchange with triphenylsulfonium chloride and an anion. Similarly, the sulfonium salts SQ-2 to SQ-12 were synthesized by ion exchange between a sulfonamide compound giving a predetermined anion and a sulfonium chloride giving a predetermined cation.

The iodonium salts IQ-1 to IQ-3 were synthesized by ion exchange between N- [2- (2-iodo-1-ylcarbonyloxy) ethyl] trifluoromethanesulfonamide and iodonium chloride giving a given cation.

Ammonium salts NQ-1 and NQ-2 are neutralized by a neutralization reaction between N- [2- (2-iodo-1-ylcarbonyloxy) ethyl] trifluoromethanesulfonamide and a quaternary ammonium hydroxide that gives a predetermined cation. Synthesized. The ammonium salts NQ-3 to NQ-5 are neutralized by a neutralization reaction between N- [2- (2-iodo-1-ylcarbonyloxy) ethyl] trifluoromethanesulfonamide and a tertiary amine that gives a predetermined cation. Synthesized.

[2] Synthesis of base polymer [Synthesis Examples 2-1 to 2-5]
Each monomer is combined and subjected to a copolymerization reaction under a THF solvent, crystallized in methanol, washed with hexane repeatedly, isolated and dried to obtain a base polymer (polymers 1 to 5) having the composition shown below. Obtained. The composition of the obtained base polymer ^{was confirmed by 1} H-NMR, and Mw and Mw / Mn were confirmed by GPC (solvent: THF, standard: polystyrene).

[3] Preparation of resist material and its evaluation [Examples 1 to 26, Comparative Examples 1 to 5]
(1) Preparation of resist material A solution in which each component is dissolved in a solvent in which 50 ppm of Polyfox636 manufactured by Omniova Co., Ltd. is dissolved as a surfactant with the compositions shown in Tables 1 to 3 is filtered through a 0.2 μm size filter. A resist material was prepared. Examples 1 to 19, 21 to 26 and Comparative Examples 1 to 4 are positive resist materials, and Examples 20 and 5 are negative resist materials.

In Tables 1 to 3, each component is as follows.
Organic solvent: PGMEA (propylene glycol monomethyl ether acetate)
DAA (diacetone alcohol)

-Acid generator: PAG1

・ Amine quencher: AQ-1

・ Quencher for comparative examples: cQ-1 to cQ-4

(2) EUV lithography evaluation Each resist material shown in Tables 1 to 3 is Si 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 50 nm was prepared by spin coating on a substrate and 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 to 3 for 60 seconds, and development was carried out with a 2.38 mass% TMAH aqueous solution for 30 seconds. In Example 20 and Comparative Example 5, a dot pattern having a size of 23 nm was obtained.
The exposure amount when the hole size and the dot size were each formed at 23 nm was measured, and this was used as the sensitivity. In addition, the dimensions of holes and 50 dots were measured using Hitachi High-Technologies Corporation's length measurement SEM (CG5000), and the dimensional variation (3σ), which is three times the standard deviation (σ) calculated from the results, was measured. CDU).
The results are also shown in Tables 1 to 3.

From the results shown in Tables 1 to 3, it was found that the resist material of the present invention containing the onium salt represented by the formula (A) has high sensitivity and a small CDU.

Claims (12)

A resist material containing a base polymer and a quencher containing an onium salt represented by the following formula (A).

[In the formula, m and n are each independently an integer of 1 to 3.
X ^BI is an iodine atom or a bromine atom.
^Rah is a (n + 1) -valent aliphatic hydrocarbon group having 1 to 20 carbon atoms, and is a halogen atom other than an ether bond, a carbonyl group, an ester bond, an amide bond, a sulton ring, a lactam ring, a carbonate group, and an iodine atom. , At least one selected from an aryl group having 6 to 12 carbon atoms, a hydroxy group and a carboxy group may be contained.
X ¹ is a single bond, an ether bond, an ester bond, an amide bond, a carbonyl group or a carbonate group.
X ² is a single-bonded or (m + 1) -valent hydrocarbon group having 1 to 20 carbon atoms, and is an ether bond, a carbonyl group, an ester bond, an amide bond, a sulton ring, a lactam ring, a carbonate group, or a halogen other than an iodine atom. It may contain at least one selected from an atom, a hydroxy group and a carboxy group.
X ³ is a single bond or a carbonyl group.
L is a single bond, −O−, −OC (= O) − or −NR—C (= O) −, and R is a hydrogen atom or a hydrocarbyl group having 1 to 4 carbon atoms.
R ¹ is a single bond or a saturated hydrocarbylene group having 1 to 20 carbon atoms, and may contain an ether bond, an ester bond or a hydroxy group.
R ² is a saturated hydrocarbyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms, and a part or all of its hydrogen atom may be substituted with a fluorine atom.
M ⁺ is a sulfonium cation represented by the following formula (Aa), an iodonium cation represented by the following formula (Ab), or an ammonium cation represented by the following formula (Ac).

(In the formula, R ^{a1 to} R ^a3 are hydrocarbyl groups having 1 to 20 carbon atoms which may independently contain a halogen atom or a hetero atom. Further, R ^a1 and R ^a2 are bonded to each other. The rings may be formed together with the sulfur atoms to which they are bonded.
R ^a4 and R ^a5 are hydrocarbyl groups having 1 to 20 carbon atoms, which may independently contain a halogen atom or a hetero atom.
R ^{a6 to} R ^a9 are independently hydrogen atoms or hydrocarbyl groups having 1 to 24 carbon atoms, and the hydrocarbyl groups are halogen atoms, hydroxy groups, carboxy groups, ether bonds, ester bonds, thiol groups, and thioester bonds. , Thionoester bond, dithioester bond, amino group, nitro group, sulfone group and at least one selected from ferrocenyl group may be contained. R ^a6 and R ^a7 may be bonded to each other to form a ring together with the nitrogen atom to which they are bonded, and R ^a6 and R ^a7 and R ^a8 and R ^a9 are bonded to each other and these are bonded to each other. A spiro ring may be formed together with the nitrogen atom, or R ^a8 and R ^a9 may be combined to form = C (R ^a10 ) (R ^a11 ). R ^a10 and R ^a11 are independently hydrogen atoms or hydrocarbyl groups having 1 to 16 carbon atoms. R ^a6 and R ^a10 may be bonded to each other to form a ring with a carbon atom and a nitrogen atom to which they are bonded, and the ring contains a double bond, an oxygen atom, a sulfur atom or a nitrogen atom. You may be. )] The resist material according to claim 1, further comprising an acid generator that generates sulfonic acid, imic acid or methidoic acid. The resist material according to claim 1 or 2, further comprising an organic solvent. The resist material according to any one of claims 1 to 3, wherein the base polymer contains a repeating unit represented by the following formula (a1) or a repeating unit represented by the following formula (a2).

(In the formula, ^RA is a hydrogen atom or a methyl group, respectively.
Y ¹ is a linking group having 1 to 12 carbon atoms containing at least one selected from a single bond, a phenylene group or a naphthylene group, or an ester bond or a lactone ring.
Y ² is a single bond or an ester bond.
Y ³ is a single bond, an ether bond or an ester bond.
R ¹¹ and R ¹² are independently acid-labile groups. )
R ¹³ is a fluorine atom, a trifluoromethyl group, a cyano group or a saturated hydrocarbyl group having 1 to 6 carbon atoms.
R ¹⁴ is a single bond or an alkanediyl 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.
a is 1 or 2. b is an integer from 0 to 4. However, 1 ≦ a + b ≦ 5. ) The resist material according to claim 4, which is a chemically amplified positive resist material. The resist material according to any one of claims 1 to 3, wherein the base polymer does not contain an acid unstable group. The resist material according to claim 6, which is a chemically amplified negative resist material. The resist material according to any one of claims 1 to 7, wherein the base polymer further contains a repeating unit represented by any of the following formulas (f1) to (f3).

(In the formula, ^RA is a hydrogen atom or a methyl group, respectively.
Z ¹ is a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group or a group having 7 to 18 carbon atoms obtained by combining these or ^{-O-Z 11, -, -} C ^{(= O) -O-Z 11} - or -C (= O) -NH-Z 11 - is. Z ¹¹ is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group or a group having 7 to 18 carbon atoms obtained by combining them, and is a carbonyl group, an ester bond, an ether bond or a hydroxy group. May include.
Z ² is a single ^{bond, -Z 21 -C (= O)} -O -, - Z 21 -O- or ^{-Z 21 -O-C (= O} ) - is. Z ²¹ is a saturated hydrocarbylene group having 1 to 12 carbon atoms and may contain a carbonyl group, an ester bond or an ether bond.
Z ³ is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene ^{group, -O-Z 31 -, -} C (= O) -O-Z 31 - or -C (= O) -NH- Z ³¹ −. Z ³¹ is a phenylene group substituted with an aliphatic hydrocarbylene group, a phenylene group, a fluorinated phenylene group, or a trifluoromethyl group having 1 to 6 carbon atoms, and is a carbonyl group, an ester bond, an ether bond, or a hydroxy group. May include.
R ^{21 to} R ²⁸ are hydrocarbyl groups having 1 to 20 carbon atoms, which may independently contain heteroatoms. Further, R ²³ and R ²⁴ or R ²⁶ and R ²⁷ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.
R ^HF is a hydrogen atom or a trifluoromethyl group.
M ^- is a non-nucleophilic opposing ion. ) The resist material according to any one of claims 1 to 8, further comprising a surfactant. A step of forming a resist film on a substrate using the resist material according to any one of claims 1 to 9, a step of exposing the resist film with high energy rays, and a developing solution for exposing the exposed resist film. A pattern forming method including a step of developing using. The pattern forming method according to claim 10, wherein the high-energy ray is an ArF excimer laser light having a wavelength of 193 nm or a KrF excimer laser light having a wavelength of 248 nm. The pattern forming method according to claim 10, wherein the high energy ray is an electron beam or extreme ultraviolet rays having a wavelength of 3 to 15 nm.