JP2003075998A - Pattern formation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pattern formation method by which lowering of contrast is solubility can be prevented and lowering of resolution can be suppressed even when the thickness of a resist film is made smaller than 250 nm. SOLUTION: A resist film 11 having <=250 nm thickness and comprising a chemical amplification type positive resist material comprising a base polymer having solubility in an alkaline developing solution varied by the action of an acid and an acid generator in which at least one electron withdrawing group has been introduced into the meta-positions of an aromatic ring constituting a counter anion and which generates the acid when irradiated with energy beams is formed on a semiconductor substrate 10. The resist film 11 is patternwise exposed by selective irradiation with electron beams 12 through a mask 13 and the patternwise exposed resist film 11 is developed to form the objective resist pattern 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pattern forming method used in a manufacturing process of a semiconductor integrated circuit device or the like, and particularly to a resist film made of a chemically amplified positive type resist material in an electron beam or 1 nm band. The present invention relates to a method of selectively irradiating extreme ultraviolet rays having a wavelength of 30 nm band to form a resist pattern.

[0002]

2. Description of the Related Art In recent years, the wavelength of exposure light used for photolithography has become shorter and shorter with the increase in density and integration of semiconductor integrated circuits, and recently, far ultraviolet light (wavelength: 300 nm band). The following) and KrF excimer laser light (wavelength: 248 nm band) have been put into practical use, and ArF excimer laser light (wavelength: 193 nm band) is approaching practical use. However, these exposure lights cannot be used for ultrafine processing whose design rule is 100 nm or less due to the problem of resolution performance.

[0003] Thus, although photolithography using a F ₂ excimer laser (157 nm band) or an electron beam as the exposure light that can be applied to ultrafine processing is being studied, F ₂
No suitable material has been found as a resist material suitable for excimer laser light and electron beams.

As a resist for electron beam, a main chain cleavage type resist composition (for example, Japanese Patent Application Laid-Open No. 1-163738)
Is used for mask fabrication and the like, but it is not used for ultra-fine processing for semiconductor device fabrication because of its sensitivity being too low and its resolution being insufficient.

Therefore, in order to overcome these problems,
Chemically amplified resist materials utilizing the catalytic action of acid generated by irradiation of energy beam have been investigated and there are many reported examples, but these all have many problems in practical use.

[0006] For example, JP-A-7-209868 and JP-A-11
JP-A-305440 and JP-A-2000-66401 propose a resist material in which poly (hydroxystyrene / styrene / tert-butyl acrylate) and triphenylsulfonium trifluoromethanesulfonate are combined,
In JP-A-7-261377 and JP-A-8-179500, a mixture of poly (p-hydroxystyrene / styrene / tert-butyl acrylate) and poly (p-hydroxystyrene / tert-butyl acrylate) is disclosed. A resist material combining a polymer and triphenylsulfonium trifluoromethanesulfonate has been proposed. However, in these resist materials, trifluoromethanesulfonic acid generated by irradiation with an energy beam has high volatility and easily moves. For this reason, under the condition that the high vacuum state continues for a long time such as when using an electron beam, the acid volatilizes or moves between the exposure step and the heating step, so that a good ultrafine pattern is obtained. Cannot be formed.

For example, in Japanese Unexamined Patent Publication No. 2000-66382, poly (p-hydroxystyrene / styrene / acrylic acid tert.
-Butyl) and triphenylsulfonium p-toluenesulfonate have been proposed as resist materials.
However, since the acidity of p-toluenesulfonic acid generated by irradiation with an energy beam is weak, the sensitivity is too low to be used.

For example, Japanese Patent Laid-Open Publication No. 8-146610 proposes a resist material in which poly (p-hydroxystyrene / tert-amyl methacrylate) and triphenylsulfonium trifluoromethanesulfonate are combined, and H.
Ito et al., J. Photopolym. Sci. Technol., 1997, Volume 10 (No. 3),
397-408, H. Ito et al., J. Photopolym. Sci. Technol., 199.
6 years, 9 (4), pp. 557-572, JP-A-7-261377 and JP-A-8-179500 disclose that poly (p-hydroxystyrene / tert-butyl acrylate) and triphenylsulfonium are used. Resist materials in combination with trifluoromethanesulfonate have been proposed. However, these cannot form a good ultrafine pattern due to the volatility and mobility of trifluoromethanesulfonic acid generated by irradiation with an energy beam. Further, even if a pattern can be formed, the polymer is too low in dry etching resistance and cannot be practically used.

For example, in Japanese Patent Laid-Open No. 11-305440, etc.,
Poly (hydroxystyrene / styrene / acrylic acid tert
-Butyl) and triphenylsulfonium perfluorobutane sulfonate have been proposed as resist materials, and in Japanese Patent Laid-Open No. 2000-66382, poly (p-hydroxystyrene / styrene / tert-butyl acrylate) has been proposed.
There has been proposed a resist material which is a combination of a triphenylsulfonium perfluorobutane sulfonate and a triphenylsulfonium perfluorobutane sulfonate.
However, these are because the perfluoroalkanesulfonic acid such as perfluorobutanesulfonic acid generated by irradiation of the energy beam has insufficient acidity, so that the sensitivity is low and the dissolution inhibitory property is too strong. Have problems such as

For example, in Japanese Unexamined Patent Publication No. 7-209868, poly (hydroxystyrene / styrene / acrylic acid tert-
Butyl) and N- (trifluoromethylsulfonyloxy)
A resist material in combination with bicyclo- [2,2,1] -hept-5-ene-2,3-dicarboximide has been proposed, and H.It
o., ACS.Symp.Ser., 1995, Volume 614 (Microelectronics T
echnology), pp. 21-34, H. Ito et al., J. Photopolym. Sci. Tec.
hnol., 1996, 9 (4), 557-572, etc., shows that poly (p-hydroxystyrene / tert-butyl acrylate) and N-camphorsulfonyloxynaphthalimide or N-trifluoromethanesulfonyloxy- Resist materials in combination with 5-norbornene-2,3-dicarboximide have been proposed. However, the trifluoromethanesulfonic acid used in these resist materials has the same problems as described above, and therefore cannot be used for ultrafine processing. Also,
Camphorsulfonic acid cannot be used because the resist material lacks sensitivity because of its weak acidity.

For example, in JP-A-11-167200 and EP-A-813113, poly (p-hydroxystyrene / styrene / tert-butyl acrylate) and di- (4-t
A resist material in combination with (ert-butylphenyl) iodonium camphorsulfonate has been proposed, and is disclosed in JP-A-11-3
In Japanese Patent No. 05441, there is proposed a resist material in which poly (hydroxystyrene / styrene / tert-butyl acrylate) and di- (4-tert-butylphenyl) iodonium perfluorobutanesulfonate are combined.
In Japanese patent publications, etc., poly (hydroxystyrene / acrylic acid)
A resist material combining tert-butyl) and di- (4-tert-butylphenyl) iodonium iodonium camphorsulfonate has been proposed. However, these are
Since iodonium salt is used, the dissolution inhibiting effect is poor, so there are problems such as poor contrast, low sensitivity and poor resolution, so it is used in ultrafine processing. Can not.

For example, in Japanese Patent Laid-Open No. 2000-187330, etc.,
A resist material has been proposed which is a combination of poly (p-1-tert-butoxyethoxystyrene / p-hydroxystyrene) and 4-butoxyphenyldiphenylsulfonium 4-trifluoromethylbenzenesulfonate, and is also disclosed in JP-A-9-1602.
In Japanese Patent No. 46, etc., poly (p-1-ethoxyethoxystyrene / p-hydroxystyrene / p-tert-butoxystyrene) is used.
And diphenyl-4-tert-butoxyphenyl) sulfonium p-toluenesulfonate have been proposed, and in JP-A-9-211866, poly (p-1-methoxypropoxystyrene / p- Hydroxystyrene / p-tert-butoxycarbonyloxystyrene)
And tris (4-tert-butoxyphenyl) sulfonium
Resist materials in combination with trifluoromethanesulfonate have been proposed. However, a polymer containing an acyclic acetal group as an acid labile group is a gas generated by decomposition upon irradiation with radiation (so-called outgas).
For this reason, the electron beam fluctuates, so that a desired pattern cannot be obtained, and the side wall of the pattern is roughened. Further, when trifluoromethanesulfonic acid is generated, the volatility is high, so that the surface insolubilized layer is generated, and thus the pattern cannot be formed.

For example, JP-A-7-261377 and JP-A-8-261377
In 179500 and JP-A-2000-187330, a combination of poly (p-tert-butoxycarbonylmethoxystyrene / p-hydroxystyrene) and triphenylsulfonium trifluoromethanesulfonate is proposed. A good ultrafine pattern cannot be formed due to the volatility and mobility of trifluoromethanesulfonic acid generated by irradiation with the energy beam.

For example, JP-A-9-160246 and JP-A-9-160246
JP211866, JP11-344808A, JP2000-1222
In Japanese Patent Application Laid-Open No. 96-2000 and Japanese Patent Application Laid-Open No. 2000-187330, triphenylsulfonium pentafluorobenzenesulfonate, tris (tert-butylphenyl) sulfonium pentafluorobenzenesulfonate, tris (tert-butoxyphenyl) sulfonium pentafluorobenzenesulfonate, triphenyl We have proposed sulfonium 3-trifluoromethylbenzene sulfonate, bis (4-methylphenyl) phenylsulfonium 3,5-bis (trifluoromethyl) benzene sulfonate, etc., but the polymers combined with these are all acid-labile groups. Since it contains an acyclic acetal group, it has problems such as fluctuation of electron beam due to outgas and roughness of pattern side wall.

As described above, the electron beam or wavelength band is 1n.
The chemically amplified positive resist used when irradiated with exposure light such as extreme ultraviolet rays in the m to 30 nm band under vacuum has high volatility of the acid generated by the energy beam irradiation, and the acid easily moves. In addition, the polymer used has insufficient dry etching resistance, the adhesion to the substrate is poor, and the beam fluctuates due to decomposition and desorption of the protective groups suspended in the polymer during irradiation of the energy beam. Due to the above reasons, a desired pattern cannot be formed, and the acidity of the acid generated by the irradiation of the energy beam is weak, so that the sensitivity of the resist material is too low.

By the way, when a fine pattern is formed by using an electron beam or extreme ultraviolet rays as the exposure light, the aspect ratio of the formed resist pattern becomes extremely large when the resist is thick. If the aspect ratio of the resist pattern is large, there is a problem that the resist pattern cannot retain its shape and a part of the resist pattern collapses, that is, a pattern collapse occurs.

Therefore, it is necessary to set the thickness of the resist film to 250 nm or less. When the thickness of the resist film is 250 nm or less, pattern collapse is less likely to occur and the resolution of the resist film is improved.

[0018]

However, when the thickness of the resist film is less than 250 nm, the solubility in the alkaline developing solution becomes high even in the unexposed portion of the resist film, and the solubility contrast (unexposed portion) is increased. Of the exposed area and the solubility of the exposed area) becomes smaller, which lowers the resolution.

In view of the above, it is an object of the present invention to provide a pattern forming method capable of suppressing deterioration of resolution by preventing deterioration of solubility contrast even when the thickness of a resist film is thinner than 250 nm. To aim.

[0020]

In order to achieve the above object, the present inventors have found that the solubility of the unexposed portion (dissolution rate)
As a result of various studies on measures to improve the contrast between the solubility and the solubility (dissolution rate) of the exposed area, when an electron-withdrawing group was introduced at the meta position of the aromatic ring that constitutes the counter anion of the acid generator, the acid It was found that the dissolution inhibitory property of the generator with respect to the base polymer is high. The present invention was made based on this finding, and is specifically realized by the following configurations.

In the pattern forming method according to the present invention, at least one electron-withdrawing group is introduced at the meta position of the aromatic ring constituting the counter anion and the base polymer whose solubility in an alkaline developing solution is changed by the action of an acid. And a step of forming a resist film having a film thickness of 250 nm or less, which is made of a positive chemically amplified resist material having an acid generator that generates an acid when irradiated with an energy beam, , Electron beam or 1nm band ~ 3
It includes a step of selectively irradiating extreme ultraviolet rays having a wavelength of 0 nm band to perform pattern exposure, and a step of developing the pattern-exposed resist film to form a resist pattern.

According to the pattern forming method of the present invention,
Since at least one electron-withdrawing group is introduced at the meta position of the aromatic ring constituting the counter anion of the acid generator, the acid generator has higher hydrophobicity than conventional acid generators. The dissolution inhibitory property of the acid generator with respect to the base polymer is increased. Therefore, the base polymer is less likely to dissolve in the alkaline developer in the region of the unexposed portion of the resist film which is in contact with the exposed portion, that is, in the region where the resist film is slightly exposed. Therefore, the contrast between the solubility of the unexposed area and the solubility of the exposed area is increased, and the resolution of the resist film is improved.

In the pattern forming method according to the present invention, a temperature of 120 ° C. or higher and 150 ° C. or lower is applied to the resist film between the step of pattern exposure of the resist film and the step of developing the resist film. It is preferable to include a step of performing post-baking.

By the way, according to the pattern forming method of the present invention, the solubility of the acid generator with respect to the base polymer is increased, so that there is a problem that the solubility with respect to the alkaline developing solution is lowered even in the exposed portion of the resist film. . However, the temperature of the resist film is 120 ° C or higher and 1
When post-baking is performed at a temperature of 50 ° C. or less, the solubility of the resist film in the exposed portion in the alkaline developing solution can be improved.

In the pattern forming method according to the present invention,
The acid generator preferably contains a compound represented by the general formula (1).

[0026]

[Chemical 7]

In the general formula (1), R ₂ and R ₄ are the same or different and are a hydrogen atom, a halogen atom, a nitro group or a trifluoromethyl group, and at least one of R ₂ and R ₄ Is not a hydrogen atom, but R ₁ , R ₃
And R ₅ are the same or different and are a hydrogen atom or a halogen atom, and R ₆ and R ₇ are the same or different and are a hydrogen atom or a straight or branched chain having 1 to 4 carbon atoms. Is an alkyl group, and n is an integer of 1 to 3.

When the acid generator contains a compound represented by the general formula (1), in the general formula (1), R ₆ is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. And R ₇ is preferably a linear or branched alkyl group having 1 to 4 carbon atoms.

When the acid generator contains the compound represented by the general formula (1), the counter anion of the compound represented by the general formula (1) is pentafluorobenzene sulfonate, 3-trifluoromethylbenzene sulfonate or 3 , 5-di-trifluoromethylbenzene sulfonate is preferred.

When the acid generator contains the compound represented by the general formula (1), it is preferable that the acid generator further contains the compound represented by the general formula (2).

[0031]

[Chemical 8]

In the general formula (2), R ₈ and R ₁₀ are the same or different and are a hydrogen atom, a halogen atom, a nitro group or a trifluoromethyl group, and at least one of R ₈ and R ₁₀ is Is not a hydrogen atom, but R ₇ , R ₉
And R ₁₁ is the same or different and is a hydrogen atom or a halogen atom.

When the acid generator contains the compound represented by the general formula (2), the counter anion of the compound represented by the general formula (2) is pentafluorobenzene sulfonate,
3-trifluoromethylbenzene sulfonate or 3,
It is preferably 5-di-trifluoromethylbenzene sulfonate.

When the acid generator contains a compound represented by the general formula (1) and a compound represented by the general formula (2), the general formula
The weight ratio of the compound represented by (1) to the compound represented by the general formula (2) is preferably 2.0 or less and 0.2 or more.

When the acid generator contains a compound represented by the general formula (1) and a compound represented by the general formula (2),
The compound represented by (1) is diphenyl-2,4,6-
Trimethylphenylsulfonium pentafluorobenzene sulfonate or diphenyl-4-methylphenylsulfonium pentafluorobenzene sulfonate, the compound represented by the general formula (2) is triphenylsulfonium pentafluorobenzene sulfonate or triphenylsulfonium-3-trifluoromethyl It is preferably benzene sulfonate.

In the pattern forming method according to the present invention,
The base polymer contains a first monomer unit represented by the general formula (3), a second monomer unit represented by the general formula (4), and a third monomer unit represented by the general formula (5). It is preferable.

[0037]

[Chemical 9]

In the general formula (3), R ₁₂ is a hydrogen atom or a methyl group.

[0039]

[Chemical 10]

In the general formula (4), R ₁₃ is a hydrogen atom or a methyl group, and R ₁₄ is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms.

[0041]

[Chemical 11]

In the general formula (5), R ₁₅ is a hydrogen atom or a methyl group, and R ₁₆ is an acid labile group.

The base polymer comprises a first monomer unit represented by the general formula (3), a second monomer unit represented by the general formula (4), and a third monomer unit represented by the general formula (5). And R ₁₆ in the general formula (5) is tert-butyl group, tert-pentyl group, 1-methylcyclohexyl group, tetrahydropyranyl group, tetrahydrofuranyl group, 1-adamantyl group, 2-methyl-2. -Adamantyl group or 4-methyl-2-oxo-4
It is preferably a tetrahydropyranyl group.

In the pattern forming method according to the present invention,
The base polymer preferably contains a compound represented by the general formula (6).

[0045]

[Chemical 12]

In the general formula (6), R ₁₂ is a hydrogen atom or a methyl group, R ₁₃ is a hydrogen atom or a methyl group,
R ₁₄ is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, R ₁₅ is a hydrogen atom or a methyl group, R ₁₆ is an acid labile group, k, l and Each of m is a positive integer, and 0.25 ≧ l / (k + 1 + m)
≧ 0.10 and 0.20 ≧ m / (k + 1 + m) ≧ 0.0
Satisfy 7.

In the pattern forming method according to the present invention,
The weight average molecular weight of the base polymer is preferably 5,000 or more and 20,000 or less, and the dispersity of the base polymer is preferably 1.0 or more and 2.5 or less.

[0048]

BEST MODE FOR CARRYING OUT THE INVENTION A pattern forming method according to an embodiment of the present invention will be described below.

First, at least one electron-withdrawing group is introduced into the meta position of the aromatic ring constituting the counter anion and the base polymer whose solubility in the alkaline developing solution is changed by the action of an acid, and is irradiated with an energy beam. Then, a positive chemically amplified resist material having an acid generator that generates an acid is prepared. The chemically amplified resist material includes a base polymer, an acid generator, a solvent, an organic base compound and a surfactant, which will be described later.

Next, the above chemically amplified resist material is applied on a semiconductor substrate such as a silicon wafer by a spin coating method or the like, and then, for example, 70-15 by a hot plate.
Pre-baking is performed by heat treatment at a temperature of 0 ° C. for 60 to 120 seconds to form a resist film having a thickness of 100 nm to 1000 nm. As the film thickness of the resist film,
It is preferably 250 nm or less, for example, 150 nm to 250 nm, and particularly preferably 150 nm to 200 nm. In this way, the resolution of the resist film is improved and the pattern collapse in the resist pattern is less likely to occur.

Next, an electron beam or 1 is applied to the resist film.
After performing pattern exposure by selectively irradiating extreme ultraviolet rays having a wavelength in the nm band to 30 nm band, the resist film subjected to the pattern exposure is subjected to 60 with a hot plate.
Post baking is performed by heat treatment for 120 seconds. By doing so, in the exposed portion of the resist film, an acid is generated by irradiation with an electron beam or extreme ultraviolet, and the acid labile group contained in the base polymer is dissociated by the action of the acid and the heating action of the post bake. Then, since the carboxylic acid is produced, the base polymer becomes alkali-soluble.

The post-baking temperature is preferably in the range of 120 ° C. to 150 ° C., more preferably 130 ° C. to 150 ° C. This way,
The solubility of the exposed portion of the resist film, which has a high dissolution inhibiting property due to the influence of the acid generator, in the alkaline developing solution is improved.

Next, the post-baked resist film is developed with an alkaline developer for 30 to 120 seconds by a spray method, a paddle method, a dip method or the like, and then washed. A resist pattern is formed.

Examples of the alkaline developer include alkaline compounds such as alkali metal hydroxides, aqueous ammonia, alkylamines, alkanolamines, heterocyclic amines and tetraalkylammonium hydroxides.
Usually, 0.01 to 20% by weight, preferably 1 to 5% by weight
An alkaline aqueous solution that is dissolved to have a concentration of is used. A particularly preferred alkaline developer is an aqueous solution of tetraalkylammonium hydroxides.
Further, a water-soluble organic solvent such as methanol or ethanol, a surfactant, or the like may be appropriately added to the developer containing the alkaline aqueous solution.

According to this embodiment, since at least one electron-withdrawing group is introduced at the meta position of the aromatic ring which constitutes the counter anion of the acid generator, the acid generator is superior to conventional acid generators. Therefore, since the hydrophobicity is increased, the dissolution inhibitory property of the acid generator with respect to the base polymer is increased. Therefore, the base polymer is less likely to dissolve in the alkaline developer in the region of the unexposed portion of the resist film which is in contact with the exposed portion, that is, in the region where the resist film is slightly exposed. Therefore, the contrast between the solubility of the unexposed area and the solubility of the exposed area is increased, and the resolution of the resist film is improved.

Further, since the post-baking is performed at a temperature of 120 ° C. or higher and 150 ° C. or lower, the solubility of the exposed portion of the resist film, which has a high dissolution inhibiting property under the influence of the acid generator, in the alkaline developing solution is improved.

The base polymer used in the pattern forming method according to the present embodiment is different from a polymer in which an acyclic acetal group or the like which decomposes immediately in the presence of an acid without heating is suspended as an acid labile group. Suspends acid labile groups that do not decompose and dissociate unless heated in the presence of. Therefore, for example, outgas is hardly generated during the irradiation of the electron beam, so that the fluctuation of the electron beam is less likely to occur.

By the way, such a base polymer is
There is a possibility that the etching resistance will be insufficient, but for this, introducing an alkyl group into the aromatic ring of the styrene unit,
This can be dealt with by introducing an alicyclic hydrocarbon group into the ester residue of the (meth) acrylic acid ester.

Although an aromatic sulfonium salt is used as the acid generator used in the pattern forming method according to the present embodiment, the carboxylic acid ester is dissociated and the acid is dissociated at a low energy irradiation amount (high sensitivity). At least one electron-withdrawing group (for example, a halogen atom, a nitro group, a trifluoromethyl group, etc.) at the meta position of the aromatic ring constituting the counter anion of the acid generator in order to suppress the volatility or mobility of the compound as much as possible. Has been introduced. Thereby, the counter anion site produces an aromatic sulfonic acid having a particularly strong acidity.

Further, according to the resist material used in the pattern forming method according to the present embodiment, since the generated acid volatilizes and migrates little, PED and storage stability do not become a problem.

The results of experiments conducted to evaluate the pattern forming method according to this embodiment will be described below.

FIG. 1 shows the relationship between the film thickness of the resist film and the resolution of line and space. In both this embodiment and the conventional example, an EB projection exposure apparatus (accelerating voltage: 100 keV) was used. This is a case where post-baking was performed at a temperature of 130 ° C. for 90 seconds after performing pattern exposure. As can be seen from FIG. 1, according to the pattern forming method of this embodiment, the film thickness of the resist film is 25
It can be seen that the resolution does not decrease even when the thickness is smaller than 0 nm.

FIG. 2 shows the relationship between the post-baking temperature and the line-and-space resolution. In both the present embodiment and the conventional example, EB projection exposure was performed on a resist film having a thickness of 200 nm. Device (accelerating voltage: 1
After pattern exposure using (00 keV),
This is the case where post-baking was performed for 0 seconds. From FIG. 2, it can be seen that when the post-baking temperature is set to 120 ° C. or higher and 150 ° C. or lower, excellent resolution can be obtained even if the resist film thickness is small.

(Acid Generator) The acid generator contained in the chemically amplified resist material used in the pattern forming method according to this embodiment will be described below.

The acid generator preferably contains a compound represented by the general formula (1).

[0066]

[Chemical 13]

In the general formula (1), R ₂ and R ₄ are the same or different and are a hydrogen atom, a halogen atom, a nitro group or a trifluoromethyl group, and at least one of R ₂ and R ₄ is Is not a hydrogen atom, but R ₁ , R ₃
And R ₅ are the same or different and are a hydrogen atom or a halogen atom, and R ₆ and R ₇ are the same or different and are a hydrogen atom or a straight or branched chain having 1 to 4 carbon atoms. Is an alkyl group, and n is an integer of 1 to 3. Incidentally, R
It is more preferable that ₆ is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, and R ₇ is a linear or branched alkyl group having 1 to 4 carbon atoms.

Examples of the halogen atom include a fluorine atom, a chlorine atom and a bromine atom.

Examples of the linear or branched alkyl group having 1 to 4 carbon atoms include methyl group, ethyl group,
Examples thereof include, but are not limited to, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, and the like.

Examples of the counter anion of the compound represented by the general formula (1) include pentafluorobenzene sulfonate, 3-trifluoromethylbenzene sulfonate and 3,5-di-trifluoromethylbenzene sulfonate.

Typical examples of the compound represented by the general formula (1) include diphenyl-2,4,6-trimethylphenylsulfonium pentafluorobenzenesulfonate and diphenyl-4-methylphenylsulfonium pentafluorobenzenesulfonate. .

The acid generator preferably contains the compound represented by the general formula (1) together with the compound represented by the general formula (2).

[0073]

[Chemical 14]

In the general formula (2), R ₈ and R ₁₀ are the same or different and are a hydrogen atom, a halogen atom, a nitro group or a trifluoromethyl group, and at least one of R ₈ and R ₁₀ is Is not a hydrogen atom, but R ₇ , R ₉
And R ₁₁ is the same or different and is a hydrogen atom or a halogen atom.

Examples of the halogen atom include a fluorine atom, a chlorine atom and a bromine atom.

As the linear or branched alkyl group having 1 to 4 carbon atoms, for example, methyl group, ethyl group,
Examples thereof include, but are not limited to, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, and the like.

The counter anion of the compound represented by the general formula (2) is preferably pentafluorobenzene sulfonate, 3-trifluoromethylbenzene sulfonate or 3,5-di-trifluoromethylbenzene sulfonate.

Typical examples of the compound represented by the general formula (2) include triphenylsulfonium pentafluorobenzene sulfonate and triphenylsulfonium 3-trifluoromethylbenzene sulfonate.

The compounds represented by the general formulas (1) and (2) both generate a sulfonic acid having a strong acidity, and therefore at least one electron-withdrawing group is present at the meta position of the aromatic ring of the counter anion. (For example, a halogen atom,
Nitro group, trifluoromethyl group, etc.) have been introduced.

The cation of the compound represented by the general formula (1) is a substituted arylsulfonium in which an alkyl group is introduced into an aromatic ring, and therefore has a very high dissolution inhibiting effect in a developing solution. Highly effective in preventing pattern collapse. Moreover, since the cation of the compound represented by the general formula (2) is an unsubstituted arylsulfonium, the effect of suppressing pattern collapse in the pattern limit resolution region is high.

Specific examples of the compound represented by the general formula (1) include, but are not limited to, the followings.

Diphenyl 4-methylphenylsulfonium pentafluorobenzene sulfonate, diphenyl
4-Methylphenylsulfonium 2,5-dichlorobenzenesulfonate, diphenyl 4-methylphenylsulfonium 2,4,5-trichlorobenzenesulfonate, diphenyl 4-methylphenylsulfonium 3-nitrobenzenesulfonate, diphenyl 4-methylphenylsulfonium 3,5- Dinitrobenzene sulfonate, diphenyl
4-Methylphenylsulfonium 3-trifluoromethylbenzenesulfonate, diphenyl 4-methylphenylsulfonium 3,5-di-trifluoromethylbenzenesulfonate, diphenyl 2,4-dimethylphenylsulfonium pentafluorobenzenesulfonate, diphenyl 2,4-dimethyl Phenylsulfonium 2,5-dichlorobenzenesulfonate, diphenyl 2,4-dimethylphenylsulfonium 2,4,5-trichlorobenzenesulfonate, diphenyl 2,4-dimethylphenylsulfonium 3-
Nitrobenzenesulfonate, diphenyl 2,4-dimethylphenylsulfonium 3,5-dinitrobenzenesulfonate, diphenyl 2,4-dimethylphenylsulfonium 3-trifluoromethylbenzenesulfonate, diphenyl 2,4-dimethylphenylsulfonium 3,5-di-tri Fluoromethylbenzene sulfonate, diphenyl
2,4,6-Trimethylphenylsulfonium pentafluorobenzene sulfonate, diphenyl 2,4,6-trimethylphenylsulfonium 2,5-dichlorobenzene sulfonate, diphenyl 2,4,6-trimethylphenylsulfonium 2,4,5-trichlorobenzene Sulfonate, diphenyl 2,4,6-trimethylphenylsulfonium 3-nitrobenzenesulfonate, diphenyl 2,4,6-trimethylphenylsulfonium 3,5-dinitrobenzenesulfonate, diphenyl 2,4,6-trimethylphenylsulfonium 3-trifluoromethyl Benzene sulfonate,
Diphenyl 2,4,6-trimethylphenylsulfonium 3,
5-di-trifluoromethylbenzene sulfonate, diphenyl 4-ethylphenyl sulfonium pentafluorobenzene sulfonate, diphenyl 4-ethylphenyl sulfonium 2,5-dichlorobenzene sulfonate, diphenyl 4-ethylphenyl sulfonium 3-trifluoromethyl benzene sulfonate, diphenyl 4-ethylphenylsulfonium 3,5-di-trifluoromethylbenzenesulfonate, diphenyl 4-n-propylphenylsulfonium pentafluorobenzenesulfonate,
Diphenyl 4-n-propylphenylsulfonium 3-trifluoromethylbenzenesulfonate, diphenyl 4-
Isopropylphenylsulfonium pentafluorobenzenesulfonate, diphenyl 4-isopropylphenylsulfonium 3-trifluoromethylbenzenesulfonate, diphenyl 4-n-butylphenylsulfonium pentafluorobenzenesulfonate, diphenyl
4-n-butylphenylsulfonium 3-trifluoromethylbenzenesulfonate, diphenyl 4-isobutylphenylsulfonium pentafluorobenzenesulfonate, diphenyl 4-isobutylphenylsulfonium
3-trifluoromethylbenzenesulfonate, diphenyl 4-sec-butylphenylsulfonium pentafluorobenzenesulfonate, diphenyl 4-sec-butylphenylsulfonium 3-trifluoromethylbenzenesulfonate, diphenyl 4-tert-butylphenylsulfonium pentafluorobenzenesulfonate, Diphenyl 4-tert-butylphenylsulfonium 2,5-dichlorobenzenesulfonate, diphenyl 4-tert-butylphenylsulfonium 2,4,5-trichlorobenzenesulfonate, diphenyl 4-tert-butylphenylsulfonium
3-nitrobenzene sulfonate, diphenyl 4-tert-
Butylphenylsulfonium 3,5-dinitrobenzenesulfonate, diphenyl 4-tert-butylphenylsulfonium 3-trifluoromethylbenzenesulfonate,
Diphenyl 4-tert-butylphenylsulfonium 3,5-
Di-trifluoromethylbenzenesulfonate, tris (4-methylphenyl) sulfonium pentafluorobenzenesulfonate, tris (4-methylphenyl) sulfonium 3-trifluoromethylbenzenesulfonate, tris (4-methylphenyl) sulfonium 3,5-di -
Trifluoromethylbenzene sulfonate, tris (4-
Ethylphenyl) sulfonium pentafluorobenzenesulfonate, tris (4-n-propylethylphenyl) sulfonium pentafluorobenzenesulfonate, tris (4-isopropylphenyl) sulfonium
Pentafluorobenzenesulfonate, tris (4-isopropylphenyl) sulfonium 3-trifluoromethylbenzenesulfonate, tris (4-isopropylphenyl) sulfonium 3,5-di-trifluoromethylbenzenesulfonate, bis (4-methylphenyl) phenylsulfonium Pentafluorobenzenesulfonate, bis (4-methylphenyl) phenylsulfonium 2,5-dichlorobenzenesulfonate, bis (4-methylphenyl) phenylsulfonium 3-trifluoromethylbenzenesulfonate, bis (4-methylphenyl) phenylsulfonium 3, 5-di-trifluoromethylbenzene sulfonate.

Examples of the compound represented by the general formula (2) include, but are not limited to, the followings.

Triphenylsulfonium pentafluorobenzene sulfonate, triphenylsulfonium
2,5-Dichlorobenzenesulfonate, triphenylsulfonium 2,4,5-trichlorobenzenesulfonate, triphenylsulfonium 3-nitrobenzenesulfonate, triphenylsulfonium 3,5-dinitrobenzenesulfonate, triphenylsulfonium 3-trifluoromethylbenzenesulfonate , Triphenylsulfonium 3,5-ditrifluoromethylbenzenesulfonate.

The compound represented by the general formula (1) can be synthesized, for example, by the following method.

That is, the compound represented by the general formula (7) is converted into a solvent for halogenated hydrocarbon such as methylene chloride, methylene bromide, 1,2-dichloroethane or chloroform,
It is dissolved in a solvent of aromatic hydrocarbon such as benzene, toluene, xylene, or a solvent in which these solvents and ethers such as ethyl ether, isopropyl ether, tetrahydrofuran, 1,2-dimethylethane are mixed.

[0087]

[Chemical 15]

In the general formula (7), R ₆ is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms.

Next, the Grignard reagent represented by the general formula (8) was added to a solution prepared by dissolving the compound represented by the general formula (7) in the above-mentioned solvent at a temperature of -10 ° C to + 100 ° C. After that, the solution was added at a temperature of 0 ° C. to 100 ° C.
The compound represented by the general formula (7) is reacted with the Grignard reagent represented by the general formula (8) by stirring for 5 to 10 hours. The reagent represented by the general formula (8) has the general formula (7)
The mixing ratio with respect to the compound represented by
5 to 3.

[0090]

[Chemical 16]

In the general formula (8), R ₇ is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, n is an integer of 1 to 3, X is a halogen atom. is there.

Next, when the reaction is completed, the reaction solution is added to 0 to
At a temperature of 30 ° C., it is treated with an aqueous hydrohalic acid solution such as an aqueous hydrobromic acid solution, an aqueous hydrochloric acid solution or an aqueous hydroiodic acid solution. In this way, the compound represented by the general formula (9) is obtained.

[0093]

[Chemical 17]

In the general formula (9), R ₆ and R ₇ are the same or different and each is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, and n is 1 to 1 Is an integer of 3 and Y is a halogen atom.

Next, the compound represented by the general formula (9) is
After dissolving in methylene chloride, methanol, ethanol, isopropanol, water or a solvent in which these are mixed, 0.9 to 1.5 mol of organic sulfonate is added to the solution, and then the temperature is set to 0 to 50 ° C. When the reaction is carried out under stirring for 0.5 to 20 hours, the compound represented by the general formula (1) is obtained.

The compound represented by the general formula (2) can also be obtained by the same method as described above.

By the way, the compound represented by the general formula (1) generates a strong acid and has an extremely high solubility inhibiting property in an alkaline developing solution. Further, the compound acid generator represented by the general formula (2) generates a strong acid and has a lower dissolution inhibiting property in an alkaline developing solution than the compound represented by the general formula (1).

Therefore, as the acid generator, an acid generator containing the compound represented by the general formula (1) alone or an acid generator containing the compound represented by the general formula (2) alone is used. However, it is more preferable to use an acid generator containing both of these compounds. The reason will be described below.

When an acid generator containing only the compound represented by the general formula (1) is used, pattern collapse easily occurs in the critical resolution region. Further, when an acid generator containing only the compound represented by the general formula (2) is used, the pattern tends to be crushed, so that the resolution is limited.

However, when an acid generator containing a compound represented by the general formula (1) and a compound represented by the general formula (2) is used, the above-mentioned problems are solved and high sensitivity and high resolution are obtained. And the pattern shape becomes good.

In this case, the weight ratio of the compound represented by the general formula (1) to the compound represented by the general formula (2) is
It is preferably 2.0 or less and 0.2 or more. The reason is as follows. That is, when the weight ratio of the compound represented by the general formula (1) to the compound represented by the general formula (2) exceeds 2.0, the sensitivity of the resist film is lowered, and when a fine resist pattern is formed. Pattern collapse may occur. On the other hand, the general formula (1)
If the weight ratio of the compound represented by the formula to the compound represented by the general formula (2) is less than 0.2, the dissolution inhibitory property is deteriorated. Therefore, when a fine resist pattern is formed, the pattern is crushed and resolved. There is a risk of deterioration in sex.

From such a viewpoint, the compound represented by the general formula (1) and the compound represented by the general formula (2) are mixed to have high sensitivity and high resolution, and a good pattern shape is obtained. It is particularly preferable to use the following compounds for forming the resist pattern of

As the compound represented by the general formula (1),
The following are listed. Diphenyl-2,4,6-trimethylphenylsulfonium pentafluorobenzenesulfonate, diphenyl-2,4,6-trimethylphenylsulfonium 3-trifluoromethylbenzenesulfonate, diphenyl-2,4,6-trimethylphenylsulfonium 3,5- Di-trifluoromethylbenzene sulfonate,
Diphenyl-2,4,6-trimethylphenylsulfonium
2,5-Dichlorobenzenesulfonate, diphenyl-4-methylphenylsulfonium pentafluorobenzenesulfonate, diphenyl-4-methylphenylsulfonium 3-trifluoromethylbenzenesulfonate, diphenyl-4-methylphenylsulfonium 3,5-di-trifluoro Methylbenzenesulfonate and diphenyl-4-methylphenylsulfonium 2,5-dichlorobenzenesulfonate are more preferable, and diphenyl-2,4,6-trimethylphenylsulfonium pentafluorobenzenesulfonate and diphenyl-4-methylphenylsulfonium
Pentafluorobenzene sulfonate.

The compounds represented by the general formula (2) include the following.

Triphenylsulfonium pentafluorobenzene sulfonate, triphenylsulfonium 3
-Trifluoromethylbenzene sulfonate, triphenylsulfonium 3,5-di-trifluoromethylbenzene sulfonate, triphenylsulfonium 2,5-dichlorobenzene sulfonate, triphenylsulfonium pentafluorobenzene sulfonate, triphenylsulfonium 3-trifluoromethylbenzene Sulfonate.

(Base Polymer) The base polymer contained in the chemically amplified resist material used in the pattern forming method according to this embodiment will be described below.

The base polymer includes a first monomer unit represented by the general formula (3), a second monomer unit represented by the general formula (4), and a third monomer unit represented by the general formula (5). It is preferable to include a unit.

[0108]

[Chemical 18]

In the general formula (3), R ₁₂ is a hydrogen atom or a methyl group.

[0110]

[Chemical 19]

In the general formula (4), R ₁₃ is a hydrogen atom or a methyl group, and R ₁₄ is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. 1 to 4 carbon atoms
Examples of the linear or branched alkyl group include, for example, methyl group, ethyl group, n-propyl group, isopropyl group,
Examples thereof include n-butyl group, isobutyl group, sec-butyl group and tert-butyl group.

[0112]

[Chemical 20]

In the general formula (5), R ₁₅ is a hydrogen atom or a methyl group, and R ₁₆ is an acid labile group. Examples of the acid labile group include tert-butyl group, tert-pentyl group, 1-
Methylcyclohexyl group, tetrahydropyranyl group, tetrahydrofuranyl group, 1-adamantyl group, 2-methyl-2
-Adamantyl group, 4-methyl-2-oxo-4-tetrahydropyranyl group (mevalonic lactonyl group), β
-Hydroxy-β-methyl-δ-valerolactonyl group,
Examples thereof include triphenylmethyl group, 1,1-diphenylethyl group, 2-phenyl-2-propyl group and the like.

Examples of the first monomer unit represented by the general formula (3) include p-hydroxystyrene and p-hydroxy-α-methylstyrene.

Examples of the second monomer unit represented by the general formula (4) include styrene, p-methylstyrene,
Examples thereof include m-methylstyrene, p-ethylstyrene, p-n-propylstyrene, p-isopropylstyrene, p-n-butylstyrene, p-isobutylstyrene, p-sec-butylstyrene and p-tert-butyl. .

Examples of the third monomer unit represented by the general formula (5) include tert-butyl acrylate, tert-pentyl acrylate, 1-methylcyclohexyl acrylate, tetrahydropyranyl acrylate, tetrahydrofuranyl acrylate, 1-adamantyl acrylate, 2-methyl-2-adamantyl acrylate, 4-methyl-2-oxo-4-tetrahydropyranyl acrylate,
Triphenylmethyl acrylate, 1,1-diphenylethyl acrylate, 2-phenyl-2-propyl acrylate, tert-butyl methacrylate, tert-pentyl methacrylate, 1-methylcyclohexyl methacrylate, tetrahydropyranyl methacrylate, Tetrahydrofuranyl methacrylate, 1-adamantyl methacrylate, 2-methyl-2-adamantyl methacrylate, 4-methyl-2-oxo-4-tetrahydropyranyl methacrylate, triphenylmethyl methacrylate, 1,1-diphenyl methacrylate Examples thereof include ethyl or 2-phenyl-2-propyl methacrylate.

As a base polymer containing a first monomer unit represented by the general formula (3), a second monomer unit represented by the general formula (4), and a third monomer unit represented by the general formula (5) Is a compound represented by the general formula (6).

[0118]

[Chemical 21]

In the general formula (6), R ₁₂ is a hydrogen atom or a methyl group, R ₁₃ is a hydrogen atom or a methyl group,
R ₁₄ is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, R ₁₅ is a hydrogen atom or a methyl group, R ₁₆ is an acid labile group, k, l and Each of m is a positive integer, and 0.25 ≧ l / (k + 1 + m)
≧ 0.10 and 0.20 ≧ m / (k + 1 + m) ≧ 0.0
Satisfy 7.

Specific examples of the polymer represented by the general formula (6) include, but are not limited to, the followings. Moreover, you may use these polymers individually or in combination.

Poly (p-hydroxystyrene / styrene /
Acrylic acid tert-butyl), poly (p-hydroxystyrene / styrene / acrylic acid tert-pentyl), poly (p-
Hydroxystyrene / styrene / 1-methylcyclohexyl acrylate), poly (p-hydroxystyrene / styrene / tetrahydropyranyl acrylate), poly (p-
Hydroxystyrene / styrene / acrylic acid 1-adamantyl), poly (p-hydroxystyrene / styrene / acrylic acid 2-methyl-2-adamantyl), poly (p-hydroxystyrene / styrene / acrylic acid 4-methyl-2)
-Oxo-4-tetrahydropyranyl), poly (p-hydroxystyrene / styrene / triphenylmethyl acrylate), poly (p-hydroxystyrene / styrene / 1,1-diphenylethyl acrylate), poly (p-hydroxy) Styrene / styrene / 2-phenyl-2-propyl acrylate), poly (p-hydroxy-α-methylstyrene / styrene / tert-butyl acrylate), poly (p-hydroxy-
α-methylstyrene / styrene / tert-pentyl acrylate), poly (p-hydroxystyrene / styrene / tert-butyl methacrylate), poly (p-hydroxystyrene / styrene / tert-pentyl methacrylate), poly (p-
Hydroxystyrene / styrene / 1-methylcyclohexyl methacrylate), poly (p-hydroxystyrene / styrene / tetrahydropyranyl methacrylate), poly (p
-Hydroxystyrene / styrene / 1-adamantyl methacrylate), poly (p-hydroxystyrene / styrene /
2-Methyl-2-adamantyl methacrylate), poly (p-hydroxystyrene / styrene / methacrylic acid 4-methyl-2-oxo-4-tetrahydropyranyl), poly (p-hydroxystyrene / styrene / methacrylic acid triphenyl) Methyl), poly (p-hydroxystyrene / styrene / methacrylic acid 1,1-diphenylethyl), poly (p-hydroxystyrene / styrene / methacrylic acid 2-
Phenyl-2-propyl), poly (p-hydroxy-α-methylstyrene / styrene / tert-butyl methacrylate),
Poly (p-hydroxy-α-methylstyrene / styrene / tert-pentyl methacrylate), Poly (p-hydroxystyrene / p-methylstyrene / tert-butyl acrylate),
Poly (p-hydroxystyrene / m-methylstyrene / tert-butyl acrylate), Poly (p-hydroxystyrene / p
-Methylstyrene / tert-pentyl acrylate), poly (p-hydroxystyrene / m-methylstyrene / tert-pentyl acrylate), poly (p-hydroxystyrene / p-
Methylstyrene / 1-methylcyclohexyl acrylate), poly (p-hydroxystyrene / m-methylstyrene / 1-methylcyclohexyl acrylate), poly (p-hydroxystyrene / p-methylstyrene / tetrahydropyranyl acrylate), Poly (p-hydroxystyrene /
p-methylstyrene / 1-adamantyl acrylate), poly (p-hydroxystyrene / m-methylstyrene / 1-adamantyl acrylate), poly (p-hydroxystyrene / p-methylstyrene / 2-methyl acrylate-2) -Adamantyl), poly (p-hydroxystyrene / m-methylstyrene / 2-methyl-2-adamantyl acrylate), poly (p-
Hydroxystyrene / p-methylstyrene / acrylic acid
4-methyl-2-oxo-4-tetrahydropyranyl), poly (p-hydroxystyrene / m-methylstyrene / acrylic acid 4-methyl-2-oxo-4-tetrahydropyranyl), poly (p-hydroxystyrene) / P-methylstyrene / triphenylmethyl acrylate), poly (p-hydroxystyrene / p-methylstyrene / acrylic acid 1,1-diphenylethyl), poly (p-hydroxystyrene / p-methylstyrene / acrylic acid 2 -Phenyl-2-propyl), poly (p-hydroxy-α-methylstyrene / p-
Methylstyrene / tert-butyl acrylate), poly (p-
Hydroxy-α-methylstyrene / p-methylstyrene / tert-pentyl acrylate), poly (p-hydroxystyrene / p-methylstyrene / tert-butyl methacrylate),
Poly (p-hydroxystyrene / m-methylstyrene / tert-butyl methacrylate), poly (p-hydroxystyrene / p-methylstyrene / tert-pentyl methacrylate),
Poly (p-hydroxystyrene / m-methylstyrene / tert-pentyl methacrylate), Poly (p-hydroxystyrene / p-methylstyrene / 1-methylcyclohexyl methacrylate), Poly (p-hydroxystyrene / m-methylstyrene) / 1-methylcyclohexyl methacrylate), poly (p-hydroxystyrene / p-methylstyrene / tetrahydropyranyl methacrylate), poly (p-hydroxystyrene / p-methylstyrene / 1-adamantyl methacrylate), poly (p -Hydroxystyrene / m-methylstyrene / 1-adamantyl methacrylate), poly (p-hydroxystyrene / p-methylstyrene / methacrylic acid 2-
Methyl-2-adamantyl), poly (p-hydroxystyrene / m-methylstyrene / 2-methyl-2-adamantyl methacrylate), poly (p-hydroxystyrene / p-methylstyrene / 4-methyl-2-methacrylate) Oxo-4-tetrahydropyranyl), poly (p-hydroxystyrene /
m-methylstyrene / 4-methyl-2-oxo-4-tetrahydropyranyl methacrylate), poly (p-hydroxystyrene / p-methylstyrene / triphenylmethyl methacrylate), poly (p-hydroxystyrene / p- Methylstyrene / 1,1-diphenylethyl methacrylate),
Poly (p-hydroxystyrene / p-methylstyrene / 2-phenyl-2-propyl methacrylate), Poly (p-hydroxy-α-methylstyrene / p-methylstyrene / tert-butyl methacrylate), Poly (p- Hydroxy-α-methylstyrene / p-methylstyrene / tert-pentyl methacrylate), poly (p-hydroxystyrene / p-ethylstyrene / tert-butyl acrylate), poly (p-hydroxystyrene / p-ethylstyrene / Acrylic acid tert-pentyl), poly (p-hydroxystyrene / p-ethylstyrene / acrylic acid 1-methylcyclohexyl), poly (p-hydroxystyrene / p-ethylstyrene / acrylic acid 1-
Adamantyl), poly (p-hydroxystyrene / p-ethylstyrene / 2-methyl-2-adamantyl acrylate),
Poly (p-hydroxystyrene / p-ethylstyrene / acrylic acid 4-methyl-2-oxo-4-tetrahydropyranyl), poly (p-hydroxy-α-methylstyrene / p-
Ethylstyrene / tert-butyl acrylate), poly (p-
Hydroxy-α-methylstyrene / p-ethylstyrene / tert-pentyl acrylate), poly (p-hydroxystyrene / p-ethylstyrene / tert-butyl methacrylate),
Poly (p-hydroxystyrene / p-ethylstyrene / tert-pentyl methacrylate), Poly (p-hydroxystyrene / p-ethylstyrene / 1-methylcyclohexyl methacrylate), Poly (p-hydroxystyrene / p-ethylstyrene) / Methacrylic acid 1-adamantyl), poly (p-hydroxystyrene / p-ethylstyrene / methacrylic acid 2
-Methyl-2-adamantyl), poly (p-hydroxystyrene / p-ethylstyrene / methacrylic acid 4-methyl-2)
-Oxo-4-tetrahydropyranyl), poly (p-hydroxy-α-methylstyrene / p-ethylstyrene / tert-butyl methacrylate), poly (p-hydroxy-α-methylstyrene / p-ethylstyrene / methacryl) Acid tert-pentyl), poly (p-hydroxystyrene / pn-propylstyrene / tert-butyl acrylate), poly (p-hydroxystyrene / pn-propylstyrene / acrylic acid te
rt-pentyl), poly (p-hydroxystyrene / pn-propylstyrene / 1-methylcyclohexyl acrylate), poly (p-hydroxystyrene / pn-propylstyrene / adamantyl acrylate), poly ( p-hydroxystyrene / pn-propylstyrene / acrylic acid
2-methyl-2-adamantyl), poly (p-hydroxystyrene / pn-propylstyrene / 4-methyl-2-oxo-4-tetrahydropyranyl acrylate), poly (p-
Hydroxy-α-methylstyrene / pn-propylstyrene / tert-butyl acrylate), poly (p-hydroxy-
α-methylstyrene / pn-propylstyrene / tert-pentyl acrylate), poly (p-hydroxystyrene / p-
n-propylstyrene / tert-butyl methacrylate),
Poly (p-hydroxystyrene / pn-propylstyrene / tert-pentyl methacrylate), Poly (p-hydroxystyrene / pn-propylstyrene / 1-methylcyclohexyl methacrylate), Poly (p-hydroxystyrene /
p-n-propylstyrene / 1-adamantyl methacrylate), poly (p-hydroxystyrene / pn-propylstyrene / 2-methyl-2-adamantyl methacrylate), poly (p-hydroxystyrene / pn-) Propylstyrene /
Methacrylic acid 4-methyl-2-oxo-4-tetrahydropyranyl), poly (p-hydroxy-α-methylstyrene / pn-propylstyrene / tert-butyl methacrylate), poly (p-hydroxy-α- Methylstyrene / p-n-
Propyl styrene / tert-pentyl methacrylate), poly (p-hydroxy styrene / p-isopropyl styrene /
Acrylic acid tert-butyl), poly (p-hydroxystyrene / p-isopropylstyrene / acrylic acid tert-pentyl), poly (p-hydroxystyrene / p-isopropylstyrene / acrylic acid 1-methylcyclohexyl), poly (p- Hydroxystyrene / p-isopropylstyrene / 1-adamantyl acrylate), poly (p-hydroxystyrene / p-isopropylstyrene / 2-methyl acrylate)
2-adamantyl), poly (p-hydroxystyrene / p-isopropylstyrene / acrylic acid 4-methyl-2-oxo-4-tetrahydropyranyl), poly (p-hydroxy-α-methylstyrene / p-isopropylstyrene / Acrylic acid tert-butyl), poly (p-hydroxy-α-methylstyrene / p-isopropylstyrene / acrylic acid tert-
Pentyl), poly (p-hydroxystyrene / p-isopropylstyrene / tert-butyl methacrylate), poly (p-
Hydroxystyrene / p-isopropylstyrene / tert-pentyl methacrylate), poly (p-hydroxystyrene / p-isopropylstyrene / 1-methylcyclohexyl methacrylate), poly (p-hydroxystyrene / p-isopropylstyrene / methacrylic acid 1 -Adamantyl),
Poly (p-hydroxystyrene / p-isopropylstyrene / 2-methyl-2-adamantyl methacrylate), Poly (p-
Hydroxystyrene / p-isopropylstyrene / methacrylic acid 4-methyl-2-oxo-4-tetrahydropyranyl), poly (p-hydroxy-α-methylstyrene / p-
Isopropyl styrene / tert-butyl methacrylate),
Poly (p-hydroxy-α-methylstyrene / p-isopropylstyrene / tert-pentyl methacrylate), Poly (p-
Hydroxystyrene / pn-butylstyrene / acrylic acid
tert-butyl), poly (p-hydroxystyrene / p-n-
Butylstyrene / tert-pentyl acrylate), poly (p-hydroxystyrene / pn-butylstyrene / 1-methylcyclohexyl acrylate), poly (p-hydroxystyrene / pn-butylstyrene / acrylic acid 1- Adamantyl), poly (p-hydroxystyrene / p-n-butylstyrene / 2-methyl-2-adamantyl acrylate),
Poly (p-hydroxystyrene / p-n-butylstyrene /
Acrylic acid 4-methyl-2-oxo-4-tetrahydropyranyl), poly (p-hydroxystyrene / pn-butylstyrene / tert-butyl methacrylate), poly (p-hydroxystyrene / pn-butylstyrene) / Methacrylic acid tert-pentyl), poly (p-hydroxystyrene / p-
n-butyl styrene / methacrylic acid 1-methylcyclohexyl), poly (p-hydroxystyrene / p-n-butyl styrene / adamantyl methacrylate), poly (p-hydroxy styrene / p-n-butyl styrene / methacrylic acid) 2-methyl-2-adamantyl), poly (p-hydroxystyrene / p-n-butylstyrene / methacrylic acid 4-methyl-2-oxo-4-tetrahydropyranyl), poly (p-hydroxystyrene / p-isobutyl) Styrene / tert-butyl acrylate), poly (p-hydroxystyrene /
p-isobutylstyrene / tert-pentyl acrylate), poly (p-hydroxystyrene / p-isobutylstyrene / 1-methylcyclohexyl acrylate), poly (p-hydroxystyrene / p-isobutylstyrene / 1-adamantyl acrylate) , Poly (p-hydroxystyrene / p-isobutylstyrene / 2-methyl acrylate-2
-Adamantyl), poly (p-hydroxystyrene / p-isobutylstyrene / acrylic acid 4-methyl-2-oxo-4-tetrahydropyranyl), poly (p-hydroxystyrene / p-isobutylstyrene / methacrylic acid tert-
Butyl), poly (p-hydroxystyrene / p-isobutylstyrene / tert-pentyl methacrylate), poly (p-
Hydroxystyrene / p-isobutylstyrene / methylcyclohexyl methacrylate), poly (p-hydroxystyrene / p-isobutylstyrene / adamantyl methacrylate), poly (p-hydroxystyrene / p-isobutylstyrene / 2-methyl methacrylate-2) -Adamantyl), poly (p-hydroxystyrene / p-isobutylstyrene / methacrylic acid 4-methyl-2-oxo-4-)
Tetrahydropyranyl), poly (p-hydroxystyrene / p-sec-butylstyrene / tert-butyl acrylate),
Poly (p-hydroxystyrene / p-sec-butylstyrene / tert-pentyl acrylate), Poly (p-hydroxystyrene / p-sec-butylstyrene / 1-methylcyclohexyl acrylate), Poly (p-hydroxystyrene / p- s
ec-Butylstyrene / acrylic acid 1-adamantyl), poly (p-hydroxystyrene / p-sec-butylstyrene /
2-Methyl-2-adamantyl acrylate, poly (p-hydroxystyrene / p-sec-butylstyrene / acrylic acid
4-methyl-2-oxo-4-tetrahydropyranyl), poly (p-hydroxystyrene / p-sec-butylstyrene / tert-butyl methacrylate), poly (p-hydroxystyrene / p-sec-butylstyrene / Methacrylic acid ter
t-pentyl), poly (p-hydroxystyrene / p-sec-
Butylstyrene / 1-methylcyclohexyl methacrylate), poly (p-hydroxystyrene / p-sec-butylstyrene / adamantyl methacrylate), poly (p-hydroxystyrene / p-sec-butylstyrene / methacrylic acid 2-) Methyl-2-adamantyl), poly (p-hydroxystyrene / p-sec-butylstyrene / methacrylic acid 4-
Methyl-2-oxo-4-tetrahydropyranyl), poly (p-hydroxystyrene / p-tert-butylstyrene /
Acrylic acid tert-butyl), poly (p-hydroxystyrene / p-tert-butylstyrene / acrylic acid tert-pentyl), poly (p-hydroxystyrene / p-tert-butylstyrene / acrylic acid 1-methylcyclohexyl), Poly (p-hydroxystyrene / p-tert-butylstyrene / 1-adamantyl acrylate), Poly (p-hydroxystyrene / p-tert-butylstyrene / 2-methyl acrylate-2
-Adamantyl), poly (p-hydroxystyrene / p-te)
rt-Butylstyrene / 4-methyl-2-oxo-4-tetrahydropyranyl acrylate), poly (p-hydroxystyrene / p-tert-butylstyrene / triphenylmethyl acrylate), poly (p-hydroxystyrene / p- t
ert-Butylstyrene / 1,1-diphenylethyl acrylate), poly (p-hydroxystyrene / p-tert-butylstyrene / 2-phenyl-2-propyl acrylate), poly (p-hydroxy-α-methylstyrene) / P-tert-butylstyrene / tert-butyl acrylate), poly (p-hydroxy-α-methylstyrene / p-tert-butylstyrene / tert-pentyl acrylate), poly (p-hydroxystyrene / p-tert) -Butylstyrene / tert-butylmethacrylate), poly (p-hydroxystyrene / p-tert-butylstyrene / tert-pentylmethacrylate), poly (p-hydroxystyrene / p-tert-butylstyrene / methacrylic acid 1- Methylcyclohexyl), poly (p-hydroxystyrene / p-tert-butylstyrene / 1-adamantyl methacrylate), poly (p-hydroxystyrene / p-tert-butylstyrene / meta 2-methyl-2-adamantyl acrylate), poly (p-hydroxystyrene / p-tert-butylstyrene / β-hydroxy-β-methyl-δ-valerolactonil methacrylate), poly (p-hydroxystyrene / pt-
ert-butylstyrene / triphenylmethylmethacrylate), poly (p-hydroxystyrene / p-tert-butylstyrene / 1,1-diphenylethylmethacrylate), poly (p-hydroxystyrene / p-tert-butylstyrene / 2-phenyl-2-propyl methacrylate), poly (p-hydroxy-α-methylstyrene / p-tert-butylstyrene / tert-butyl methacrylate), poly (p-hydroxy-α-methylstyrene / p-tert -Butylstyrene / methacrylic acid
tert-pentyl).

Of the above polymers, the following polymers are
It is particularly excellent in terms of high resolution and etching resistance.
In addition, you may use these polymers individually or in combination.

Poly (p-hydroxystyrene / styrene /
Tert-butyl acrylate), poly (p-hydroxystyrene / styrene / 1-methylcyclohexyl acrylate), poly (p-hydroxystyrene / styrene / adamantyl acrylate), poly (p-hydroxystyrene / styrene / acrylic) Acid 2-methyl-2-adamantyl),
Poly (p-hydroxystyrene / styrene / acrylic acid
β-hydroxy-β-methyl-δ-valerolactonyl), poly (p-hydroxystyrene / p-methylstyrene / tert-butyl acrylate), poly (p-hydroxystyrene / m-
Methylstyrene / tert-butyl acrylate), poly (p-
Hydroxystyrene / p-methylstyrene / acrylic acid 1
-Methylcyclohexyl), poly (p-hydroxystyrene / m-methylstyrene / acrylic acid 1-methylcyclohexyl), poly (p-hydroxystyrene / p-methylstyrene / acrylic acid 1-adamantyl), poly (p-hydroxystyrene) / M-methylstyrene / acrylic acid 1-adamantyl), poly (p-hydroxystyrene / p-methylstyrene / acrylic acid 2-methyl-2-adamantyl), poly (p-hydroxystyrene / m-methylstyrene / acrylic acid 2-methyl-2-adamantyl), poly (p-hydroxystyrene / p-methylstyrene / acrylic acid β-hydroxy
-β-methyl-δ-valerolactonyl), poly (p-hydroxystyrene / m-methylstyrene / acrylic acid β-hydroxy-β-methyl-δ-valerolactonyl), poly (p-hydroxystyrene / p-tert-butylstyrene) / Acrylic acid
tert-butyl), poly (p-hydroxystyrene / p-tert
-Butylstyrene / acrylic acid 1-methylcyclohexyl), poly (p-hydroxystyrene / p-tert-butylstyrene / acrylic acid 1-adamantyl), poly (p-hydroxystyrene / p-tert-butylstyrene / acrylic acid
2-methyl-2-adamantyl), poly (p-hydroxystyrene / p-tert-butylstyrene / β-hydroxy-β-methyl-δ-valerolactonyl acrylate) are preferred, and poly (p-hydroxystyrene / styrene / acrylic Acid ter
t-butyl), poly (p-hydroxystyrene / styrene /
1-adamantyl acrylate), poly (p-hydroxystyrene / p-methylstyrene / tert-butyl acrylate), poly (p-hydroxystyrene / p-methylstyrene / 1-adamantyl acrylate), poly (p-hydroxy) Styrene / m-methylstyrene / tert-butyl acrylate), poly (p-hydroxystyrene / m-methylstyrene / 1-adamantyl acrylate).

The method for synthesizing the polymer represented by the general formula (6) will be described below.

First, the first monomer unit represented by the general formula (3), the second monomer unit represented by the general formula (4), and the third monomer unit represented by the general formula (5) are used as monomers. To 1 to 10 volumes of a suitable solvent such as toluene, 1,4-dioxane, tetrahydrofuran, isopropanol or methyl ethyl ketone to obtain a solution.

Next, the obtained solution was added to a polymerization initiator, such as azoisobutyronitrile or 2,2'-azobis, in an amount of 0.1 to 30% by weight with respect to the monomer under a nitrogen stream.
(2,4-dimethylvaleronitrile), 2,2'-azobis (methyl 2-methylpropionate), 2,2'-azobis (2-methylbutyronitrile), benzoyl peroxide or lauroyl peroxide exist Under a temperature of 50 to 150 ° C. under
After reacting for 1 to 20 hours, the reaction product is treated according to a conventional method for obtaining a polymer to obtain a polymer represented by the general formula (6).

By the way, the weight average molecular weight (Mw) of the polymer represented by the general formula (6) is usually 3,000 to 5
It is in the range of 50,000, preferably 5,000 to 2
The range is 5,000, and more preferably 5,000 to
It is in the range of 20,000. In addition, the degree of dispersion (Mw / M
n) is usually 1.0 to 3.5, preferably 1.
0 to 2.5.

(Solvent) The solvent contained in the chemically amplified resist material used in the pattern forming method according to this embodiment will be described below.

Specific examples of the solvent include, but are not limited to, the followings.

Methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, methyl lactate, ethyl lactate, propyl lactate, acetic acid
2-ethoxyethyl, methyl pyruvate, ethyl pyruvate, methyl 3-methoxyprobionate, ethyl 3-methoxyprobionate, N, N-dimethylformamide, N, N-dimethylacetamide, cyclohexanone, methyl ethyl ketone, 2-hebutanone , Β-propiolactone, β-butyrolactone, γ-butyrolactone, γ-valerolactone, δ
-Valerolactone, 1,4-dioxane, diethylene glycol monomethyl ether, diethylene glycol dimethyl ether, ethylene glycol monoisopropyl ether, N-methyl-2-pyrrolidone.

These solvents may be used alone or in combination of two or more.

The amount of the solvent is usually 3 with respect to the weight of the total solid content regardless of which resist material is used.
To 40 times by weight, and preferably 7 to 20 times by weight.

(Organic Basic Compound) The organic basic compound contained in the chemically amplified resist material used in the pattern forming method according to this embodiment will be described below.

Specific examples of the organic base compound added for the purpose of adjusting the sensitivity include, but are not limited to, the followings.

Pyridine, picoline, triethylamine,
Tri-n-butylamine, tri-n-octylamine, dioctylmethylamine, dicyclohexylmethylamine, N-
Methylpyrrolidine, N-methylpiperidine, triethanolamine, triisopropanolamine, dimethyldodecylamine, dimethylhexadecylamine, tribenzylamine, tris [2- (2-methoxyethoxy) ethyl]
Amine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetra-n-butylammonium hydroxide, polyvinyl pyridine, poly (vinyl pyridine / methyl methacrylate). These may be used alone or in combination of two or more.

The amount of the basic organic compound used is usually in the range of 0.000001 to 1% by weight, preferably 0.00001 to 10% by weight, based on the total weight of the polymer, whichever resist material is used. It is in the range of 0.5% by weight.

(Surfactant) The surfactant which is added as necessary to the chemically amplified resist material used in the pattern forming method according to this embodiment will be described below.

Specific examples of the surfactant include, but are not limited to, the followings.

Fluorard (trade name: manufactured by Sumitomo 3M Ltd.), Surflon (trade name: manufactured by Asahi Glass Co., Ltd.),
Fluorine-containing nonionic surfactants such as Unidyne (trade name: Daikin Industries, Ltd.), Megafac (trade name: Dainippon Ink & Co., Inc.), F-top (trade name: Tochem Products Co., Ltd.) Agents, polyethylene glycol, polypropylene glycol, polyoxyethylene cetyl ether, etc.

As for the amount of the surfactant added as necessary, whichever resist material is used,
Usually 0.000 each, based on the total weight of the polymer
001 to 1% by weight, preferably 0.000
It is in the range of 01 to 0.5% by weight.

(Synthesis Example 1 of Base Polymer) Poly (p-hydroxystyrene / styrene / tert-butyl acrylate) which is a base polymer represented by the general formula (6) is shown below.
A synthesis example of will be described.

First, p-hydroxystyrene (84.1
g), styrene (20.8 g) and tert-butyl acrylate (12.8 g) were dissolved in isopropanol (400 mL), and then azobisisobutyronitrile (14.1 g) was added to the solution. Then, the reaction was performed for 6 hours at a temperature of 80 ° C. under a nitrogen stream.

Next, the reaction product was poured into water (10 L) to cause precipitation, and the precipitated crystals thus obtained were collected by filtration, dried under reduced pressure and dried to give poly (p-hydroxystyrene / styrene / acrylic acid tert. -Butyl) powder powder (9
5 g) was obtained. The composition ratio of the obtained copolymer was 13CN.
When determined by MR measurement, p-hydroxystyrene unit: styrene unit: tert-butyl acrylate unit =
It was 7: 2: 1. The weight average molecular weight (Mw) of the copolymer determined by gel permeation chromatography using polystyrene as a standard is about 1
And the dispersity (Mw / Mn) was about 1.9.

(Synthesis example 2 of base polymer) Poly (p-hydroxystyrene / p-methylstyrene / acrylic acid tert-) which is a base polymer represented by the general formula (6) is shown below.
Butyl) synthesis examples will be described.

First, styrene (20.
The raw material in which 8 g) was replaced with p-methylstyrene (23.6 g) was subjected to the same synthesis and post-treatment as in Synthesis Example 1 to give poly (p-hydroxystyrene / p-methylstyrene / acrylic acid tert. -Butyl) was obtained as light brown powder crystals (96 g). The composition ratio of the obtained copolymer is 1
3C NMP measurement method, p-hydroxystyrene unit: p-methylstyrene unit: acrylic acid tert-
Butyl units = 7: 2: 1. Further, the weight average molecular weight (Mw) of the copolymer determined by a gel permeation chromatography measurement method using polystyrene as a standard is about 10,500, and the polydispersity (Mw / M
n) was about 1.85.

(Synthesis Example 3 of Base Polymer) A synthesis example of poly (p-hydroxystyrene / styrene / 1-adamantyl acrylate) which is a base polymer represented by the general formula (6) will be described below.

First, p-hydroxystyrene (87.7
g), styrene (18.7 g) and 1-adamantyl acrylate (18.6 g) in isopropanol (400 m
L), and then 2,2'-azobis (methyl 2-methylpropionate) (trade name: V-601, manufactured by Wako Pure Chemical Industries, Ltd.) (10.0 g) was added to the solution. Then, the mixture was reacted for 6 hours at a temperature of 80 ° C. under a nitrogen stream.

Next, the reaction product was poured into water (10 L) to cause precipitation, and the precipitated crystal thus obtained was filtered, depressurized and dried to give poly (p-hydroxystyrene / styrene / acrylic acid 1 A slightly brown powder crystal (100 g) consisting of (adamantyl) was obtained. The composition ratio of the obtained copolymer is 1
The p-hydroxystyrene unit: styrene unit: acrylic acid 1-adamantyl unit = 73: 18: 9 as determined by the 3CNMP measurement method. Further, the weight average molecular weight (Mw) of the copolymer determined by gel permeation chromatography measurement method using polystyrene as a standard is about 9,800, and the dispersity (Mw / Mn) is about 1.80. It was

(Synthesis Example 1 of Acid Generator) The following is represented by the general formula (1)
A synthesis example of diphenyl-2,4,6-trimethylphenylsulfonium pentafluorobenzenesulfonate, which is a compound represented by, will be described.

(First Step) First, diphenyl sulfoxide (24.0 g) was dissolved in tetrahydrofuran (600 mL) in a nitrogen atmosphere, and then chlorotrimethylsilane (31.5 g) was injected into the solution. Next, a Grignard reagent obtained by a conventional method from 2-bromomesitylene (60 g) and magnesium (4.70 g) was added dropwise to the solution under ice cooling, and these were reacted at the same temperature for 3 hours. . When the reaction was completed, a 24% aqueous solution of hydrobromic acid (480 mL) was added dropwise to the reaction solution at a temperature of 0 to 5 ° C, and then toluene (600 mL) was injected and stirred. Next, after separating the stirred reaction liquid, 1
The organic layer was extracted twice with a 2% aqueous hydrobromic acid solution (120 mL), and then methylene chloride (4
The organic layer was extracted 3 times with 80 mL. The obtained organic layer was dried over anhydrous magnesium sulfate and then concentrated under reduced pressure to obtain white crystals (22.0 g) made of diphenyl-2,4,6-trimethylphenylsulfonium bromide.
The characteristics of the obtained white crystals are as follows.

Melting point: 199-200 ° C. 1HNMR (CDCl3) δppm: 2.36 (6H, s, CH3 × 2), 2.43 (3H,
s, CH3), 7.21 (2H, 7.69-7.74 (4H, m, Ar-H), 7.75-7.79
(6H, m, Ar-H)

(Second Step) Next, white crystals (19.3 g; 0.05 mo) of diphenyl-2,4,6-trimethylphenylsulfonium bromide obtained in the first step.
l) was dissolved in methanol (100 mL), and pentafluorobenzenesulfonic acid tetramethylammonium salt (20.9 g; 0.065 mol) was added to the solution,
Then, the mixture was stirred and reacted at room temperature for 4 hours. After the reaction was completed, water (100 mL) was added to the residue obtained by concentrating the reaction solution.
And methylene chloride (100 mL) were added, and the mixture was stirred and allowed to stand. Next, after separating the organic layer, washing with water (100 mL ×
(1 time + 50 mL × 1 time), and then dried over anhydrous MgSO ₄ . After the desiccant was filtered off, it was concentrated under reduced pressure to obtain white crystals of diphenyl-2,4,6-trimethylphenylsulfonium pentafluorobenzenesulfonate (2
6.8 g) was obtained. The characteristics of the obtained white crystals are as follows.

Melting point: 132-133 ° C. 1HNMR (CDCl3) δppm: 2.31 (6H, s, CH3 × 2), 2.41 (3H,
s, CH3), 7.08 (2H, s, Ar-H), 7.50-7.51 (4H, s, Ar-
H), 7.63-7.82 (6H, m, Ar-H)

(Synthesis Example 2 of Acid Generator) The following general formula (1)
Triphenylsulfonium, a compound represented by
A synthesis example of pentafluorobenzene sulfonate will be described.

(First Step) Synthesis of Acid Generator The 2-bromomesitylene used in the first step of Synthesis Example 1 was converted to bromobenzene (4
The same reaction and post-treatment as in the first step of Synthesis Example 1 were carried out except that the amount was changed to 7.3 g) to obtain white crystals (20.2 g) made of triphenylsulfonium bromide.
The characteristics of the obtained white crystals are as follows.

Melting point: 288-290 ° C 1HNMR (CDCl3) δppm: 7.72-7.89 (15H, m, Ar-H)

(Second Step) Next, the triphenylsulfonium bromide obtained in the first step (17.2 g;
05 mol) and pentafluorobenzenesulfonic acid tetramethylammonium salt (20.9 g; 0.065 m)
was used to carry out the same reaction and post-treatment as in the second step of Synthesis Example 2 of the acid generator to obtain a colorless viscous oily product (19.1 g) consisting of triphenylsulfonium pentafluorobenzenesulfonate. . The characteristics of the obtained colorless viscous oil are as follows.

1HNMR (CDCl3) δppm: 7.25-7.80 (15H, m,
Ar-H)

(Synthesis Examples 3 to 8 of Acid Generator) Various acid generators were synthesized in the same manner as in Synthesis Example 1 of acid generator. Physical properties of each compound obtained in Synthesis Examples 3 to 8 are shown in [Table 1].

[0160]

[Table 1]

The compounds obtained in Synthetic Examples 3, 4, 5, and 8 are compounds represented by the general formula (1), and the compounds obtained in Synthetic Examples 6 and 7 are represented by the general formula (2). It is a compound.

(Example 1) Hereinafter, Example 1 of the pattern forming method according to the present invention will be described with reference to FIGS. 3 (a) to 3 (d).

First, a chemically amplified resist material having the following composition was prepared.

[0164]   Poly (p-hydroxystyrene / styrene / tert-butyl acrylate) [base Compound of Polymer Synthesis Example 1] ……………………………………………… 6.0g   Diphenyl-2,4,6-trimethylphenylsulfonium pentafluorobenzene Sulfonate [Compound of Synthesis Example 1 of Acid Generator] ………………………… 0.3g   Dicyclohexylmethylamine ………………………………………… 0.01g   Fluorine-containing nonionic surfactant [commercial item] ……………………………… 0.1g   Propylene glycol monomethyl ether acetate ……………… 60.0g

Next, the above chemically amplified resist material was filtered through a 0.1 μm membrane filter, spin-coated on the silicon substrate 10, and then prebaked at 130 ° C. for 90 seconds with a hot plate. Then, as shown in FIG. 3A, a resist film 11 having a thickness of 0.2 μm was obtained.

Next, as shown in FIG. 3 (b), the electron beam 12 emitted from the EB projection exposure apparatus (accelerating voltage 100 keV) is applied to the resist film 11 as a mask 1.
The pattern exposure was performed by irradiating the light through No. 3.

Next, as shown in FIG. 3 (c), the resist film 11 subjected to the pattern exposure was subjected to post-baking 14 for 90 seconds at a temperature of 130 ° C. using a hot plate.

Next, as shown in FIG. 3D, the post-baked resist film 11 was developed using a 2.38% tetramethylammonium hydroxide aqueous solution, and then washed with water. Then, a resist pattern 15 composed of an unexposed portion of the resist film 11 was formed.

The obtained resist pattern 15 was 10.
It had a line-and-space resolution of 80 nm with a sensitivity of 0 μC / cm ² , and had a good rectangular pattern shape.

(Second Embodiment) A second embodiment of the pattern forming method according to the present invention will be described below.

First, a chemically amplified resist material having the following composition was prepared.

[0172]   Poly (p-hydroxystyrene / styrene / tert-butyl acrylate) ………… …………………………………………………………………………………… 6.0g   Triphenylsulfonium pentafluorobenzene sulfonate [acid generator Compound of Synthetic Example 2] ……………………………………………………………… 0.3g   Dicyclohexylmethylamine ………………………………………… 0.01g   Fluorine-containing nonionic surfactant [commercial item] ……………………………… 0.1g   Propylene glycol monomethyl ether acetate ……………… 60.0g

Next, a resist pattern was formed using the above chemically amplified resist material in the same manner as in Example 1.

The resist pattern obtained was 7.6 μC.
The film had a line-and-space resolution of 100 nm with a sensitivity of / cm ² , and the surface layer of the film was slightly rounded as a pattern shape.

Example 3 Example 3 of the pattern forming method according to the present invention will be described below with reference to FIGS. 4 (a) to 4 (d).

First, a chemically amplified resist material having the following composition was prepared.

[0177]   Poly (p-hydroxystyrene / styrene / tert-butyl acrylate) ………… …………………………………………………………………………………… 6.0g   Diphenyl-2,4,6-trimethylphenylsulfonium 2,5-dichlorobenzene Ruphonate [Compound of Synthesis Example 3 of Acid Generator] ……………………………… 0.3g   Dicyclohexylmethylamine ………………………………………… 0.01g   Fluorine-containing nonionic surfactant [commercial item] ……………………………… 0.1g   Propylene glycol monomethyl ether acetate ……………… 60.0g

Next, the chemically amplified resist material was filtered through a 0.1 μm membrane filter, spin-coated on the silicon substrate 20, and then prebaked at 130 ° C. for 90 seconds with a hot plate. Then, as shown in FIG. 4A, a resist film 21 having a thickness of 0.2 μm was obtained.

Next, as shown in FIG. 4B, the extreme ultraviolet rays (wavelength: 13.5) reflected by a mask (not shown) after being emitted from the extreme ultraviolet exposure device (NA: 0.1).
(nm band) 22 for pattern exposure.

Next, as shown in FIG. 4 (c), the resist film 21 subjected to the pattern exposure was subjected to post-baking 23 for 90 seconds at a temperature of 130 ° C. using a hot plate.

Next, as shown in FIG. 4D, the post-baked resist film 21 was developed using a 2.38% tetramethylammonium hydroxide aqueous solution, and then washed with water. Then, a resist pattern 24 composed of an unexposed portion of the resist film 21 was formed.

The obtained resist pattern 24 is 8.5.
It had a line-and-space resolution of 70 nm with a sensitivity of mJ / cm ² , and had a good rectangular pattern shape.

(Fourth Embodiment) A fourth embodiment of the pattern forming method according to the present invention will be described below.

First, a chemically amplified resist material having the following composition was prepared.

[0185]   Poly (p-hydroxystyrene / styrene / tert-butyl acrylate) ………… …………………………………………………………………………………… 6.0g   Diphenyl-2,4,6-trimethylphenylsulfonium 3-trifluoromethyl ester Benzenesulfonate [Compound of Synthesis Example 4 of acid generator] …………………… 0.3g   Dicyclohexylmethylamine ………………………………………… 0.01g   Fluorine-containing nonionic surfactant [commercial item] ……………………………… 0.1g   Propylene glycol monomethyl ether acetate ……………… 60.0g

Then, a resist pattern was formed using the above chemically amplified resist material in the same manner as in Example 1.

The resist pattern obtained was 13.3 μm.
It had a sensitivity of C / cm ² and a line-and-space resolution of 80 nm, and the pattern shape was almost rectangular.

(Fifth Embodiment) A fifth embodiment of the pattern forming method according to the present invention will be described below.

First, a chemically amplified resist material having the following composition was prepared.

[0190]   Poly (p-hydroxystyrene / styrene / tert-butyl acrylate) ………… …………………………………………………………………………………… 6.0g   Diphenyl-2,4,6-trimethylphenylsulfonium 3-nitrobenzenesulfo Nate [Compound of Synthesis Example 5 of acid generator] …………………………………… 0.3g   Dicyclohexylmethylamine ………………………………………… 0.01g   Fluorine-containing nonionic surfactant [commercial item] ……………………………… 0.1g   Propylene glycol monomethyl ether acetate ……………… 60.0g

Then, a resist pattern was formed using the above chemically amplified resist material in the same manner as in Example 3.

The resist pattern obtained was 7.8 mJ.
It had a line-and-space resolution of 70 nm with a sensitivity of / cm ² , and the pattern shape was almost rectangular.

(Sixth Embodiment) A sixth embodiment of the pattern forming method according to the present invention will be described below.

First, a chemically amplified resist material having the following composition was prepared.

[0195]   Poly (p-hydroxystyrene / styrene / tert-butyl acrylate) ………… …………………………………………………………………………………… 6.0g   Triphenylsulfonium 2,5-dichlorobenzene sulfonate [Compound of acid generator Compound of Example 6] ……………………………………………………………… 0.3g   Dicyclohexylmethylamine ………………………………………… 0.01g   Fluorine-containing nonionic surfactant [commercial item] ……………………………… 0.1g   Propylene glycol monomethyl ether acetate ……………… 60.0g

Then, a resist pattern was formed using the above chemically amplified resist material in the same manner as in Example 1.

The resist pattern obtained was 5.0 μC.
The film had a line-and-space resolution of 90 nm with a sensitivity of / cm ² , and the film surface layer was slightly rounded as a pattern shape.

(Embodiment 7) Embodiment 7 of the pattern forming method according to the present invention will be described below.

First, a chemically amplified resist material having the following composition was prepared.

[0200]   Poly (p-hydroxystyrene / styrene / tert-butyl acrylate) ………… …………………………………………………………………………………… 6.0g   Triphenylsulfonium 3,5-di-trifluoromethylbenzenesulfonate [Compound of Synthesis Example 7 of Acid Generator] 0.3 g   Dicyclohexylmethylamine ………………………………………… 0.01g   Fluorine-containing nonionic surfactant [commercial item] ……………………………… 0.1g   Propylene glycol monomethyl ether acetate ……………… 60.0g

Next, a resist pattern was formed in the same manner as in Example 3 using the above chemically amplified resist material.

The obtained resist pattern was 6.5 mJ.
It had a line-and-space resolution of 80 nm with a sensitivity of / cm ² , and the pattern shape was almost rectangular.

(Embodiment 8) Embodiment 7 of the pattern forming method according to the present invention will be described below.

First, a chemically amplified resist material having the following composition was prepared.

[0205]   Poly (p-hydroxystyrene / styrene / tert-butyl acrylate) ………… …………………………………………………………………………………… 6.0g    Diphenyl-2,4,6-trimethylphenylsulfonium pentafluorobenze Sulfonate ………………………………………………………………………… 0.1g   Triphenylsulfonium pentafluorobenzene sulfonate ... 0.2 g   Dicyclohexylmethylamine ………………………………………… 0.01g   Fluorine-containing nonionic surfactant [commercial item] ……………………………… 0.1g   Propylene glycol monomethyl ether acetate ……………… 60.0g

Next, a resist pattern was formed using the above chemically amplified resist material in the same manner as in Example 1.

The resist pattern obtained was 5.2 μC.
It had a line-and-space resolution of 80 nm with a sensitivity of / cm ² , and the pattern shape was almost rectangular.

(Ninth Embodiment) A ninth embodiment of the pattern forming method according to the present invention will be described below.

First, a chemically amplified resist material having the following composition was prepared.

[0210]   Poly (p-hydroxystyrene / p-methylstyrene / tert-butyl acrylate) [ Compound of Synthesis Example 2 of Base Polymer] ………………………………………… 6.0g   Diphenyl-2,4,6-trimethylphenylsulfonium pentafluorobenzene Sulfonate …………………………………………………………………… 0.1g   Triphenylsulfonium pentafluorobenzene sulfonate ... 0.2 g   Dicyclohexylmethylamine ………………………………………… 0.02g   Fluorine-containing nonionic surfactant [commercial item] ……………………………… 0.1g   Propylene glycol monomethyl ether acetate ……………… 40.0g   Propylene glycol monomethyl ether ……………………………… 20.0g

Next, a resist pattern was formed using the above chemically amplified resist material in the same manner as in Example 3.

The resist pattern obtained was 7.0 mJ.
It had a line-and-space resolution of 80 nm with a sensitivity of / cm ² , and the pattern shape was almost rectangular.

(Embodiment 10) Embodiment 10 of the pattern forming method according to the present invention will be described below.

First, a chemically amplified resist material having the following composition was prepared.

[0215]   Poly (p-hydroxystyrene / styrene / acrylic acid 1-adamantyl) [Ba Compound of Synthesis Example 3 of Spolymer] ……………………………………………… 6.0g   Diphenyl-2,4,6-trimethylphenylsulfonium pentafluorobenzene Sulfonate …………………………………………………………………… 0.1g   Triphenylsulfonium pentafluorobenzene sulfonate ... 0.2 g   Dicyclohexylmethylamine ………………………………………… 0.02g   Fluorine-containing nonionic surfactant [commercial item] ……………………………… 0.1g   Propylene glycol monomethyl ether acetate ……………… 40.0g   Propylene glycol monomethyl ether ……………………………… 20.0g

Next, a resist pattern was formed using the above chemically amplified resist material in the same manner as in Example 1.

The resist pattern obtained was 9.4 μC.
It had a line-and-space resolution of 80 nm with a sensitivity of / cm ² , and the pattern shape was almost rectangular.

(Embodiment 11) An embodiment 11 of the pattern forming method according to the present invention will be described below.

First, a chemically amplified resist material having the following composition was prepared.

Poly (p-hydroxystyrene / styrene / tert-butyl acrylate) ………………………………………………………………………………………… ………… 6.0g Diphenyl-4-methylphenylsulfonium pentafluorobenzene sulfonate [Compound of Synthesis Example 8 of acid generator] …………………………………… 0.3g Dicyclohexylmethylamine ………………………………………… 0.01g Fluorine-containing nonionic surfactant [commercially available product] ………………………… 0.1g Propylene glycol monomethyl ether acetate… …………… 60.0g Next, Example 3 was prepared using the above chemically amplified resist material.
A resist pattern was formed in the same manner as in.

The obtained resist pattern has a length of 10.8 m.
It had a sensitivity of J / cm ² and a line-and-space resolution of 80 nm, and the pattern shape was almost rectangular.

(Embodiment 12) An embodiment 11 of the pattern forming method according to the present invention will be described below.

First, a chemically amplified resist material having the following composition was prepared.

[0224]   Poly (p-hydroxystyrene / styrene / tert-butyl acrylate) ………… …………………………………………………………………………………… 6.0g   Diphenyl-4-methylphenylsulfonium pentafluorobenzenesulfone Out ……………………………………………………………………………… 0.15g   Triphenylsulfonium 2,5-dichlorobenzene sulfonate ... 0.15g   Dicyclohexylmethylamine ………………………………………… 0.01g   Fluorine-containing nonionic surfactant [commercial item] ……………………………… 0.1g   Propylene glycol monomethyl ether acetate ……………… 60.0g

Then, a resist pattern was formed in the same manner as in Example 1 using the above chemically amplified resist material.

The resist pattern obtained was 11.3 μm.
It had a line-and-space resolution of 70 nm with a sensitivity of C / cm ² , and the pattern shape was almost rectangular.

(Embodiment 13) An embodiment 11 of the pattern forming method according to the present invention will be described below.

First, a chemically amplified resist material having the following composition was prepared.

[0229]   Poly (p-hydroxystyrene / styrene / tert-butyl acrylate) ………… …………………………………………………………………………………… 6.0g   Diphenyl-4-methylphenylsulfonium pentafluorobenzenesulfone Out ……………………………………………………………………………… 0.15g   Triphenylsulfonium 3,5-di-trifluoromethylbenzenesulfonate ………………………………………………………………………………… 0.15g   Dicyclohexylmethylamine ………………………………………… 0.01g   Fluorine-containing nonionic surfactant [commercial item] ……………………………… 0.1g   Propylene glycol monomethyl ether acetate ……………… 60.0g

Next, a resist pattern was formed in the same manner as in Example 3 using the above chemically amplified resist material.

The resist pattern obtained was 7.7 mJ.
It had a line-and-space resolution of 70 nm with a sensitivity of / cm ² , and the pattern shape was almost rectangular.

(Embodiment 14) An embodiment 11 of the pattern forming method according to the present invention will be described below.

First, a chemically amplified resist material having the following composition was prepared.

[0234]   Poly (p-hydroxystyrene / p-methylstyrene / tert-butyl acrylate) …………………………………………………………………………………… 6.0g   Diphenyl-2,4,6-trimethylphenylsulfonium 3-trifluoromethyl ester Benzene sulfonate …………………………………………………………………… 0.1g   Triphenylsulfonium pentafluorobenzene sulfonate 0.2g   Dicyclohexylmethylamine ………………………………………… 0.01g   Fluorine-containing nonionic surfactant [commercial item] ……………………………… 0.1g   Propylene glycol monomethyl ether acetate ……………… 60.0g

Then, a resist pattern was formed using the above chemically amplified resist material in the same manner as in Example 1.

The resist pattern obtained was 8.8 μC.
It had a line-and-space resolution of 70 nm with a sensitivity of / cm ² , and the pattern shape was almost rectangular.

Comparative examples carried out to evaluate the present invention will be described below. The acid generator used in each comparative example was obtained by the same method as in Synthesis Example 1 of the acid generator.

[Comparative Example 1] A pattern forming method according to Comparative Example 1 will be described below with reference to FIGS. 5 (a) to 5 (d).

First, a chemically amplified resist material having the following composition was prepared.

Poly (p-hydroxystyrene / styrene / tert-butyl acrylate) ………………………………………………………………………………………… ………… 6.0g Triphenylsulfonium trifluoromethanesulfonate ………… 0.3g Dicyclohexylmethylamine …………………………………… 0.01g Fluorine-containing nonionic surfactant [commercially available Product] ………………………… 0.1g Propylene glycol monomethyl ether acetate ………… 60.0g Next, the above chemically amplified resist material was filtered through a 0.1 μm membrane filter. After that, spin coating is performed on the silicon substrate 1 and then 130 by a hot plate.
Prebaking for 90 seconds at a temperature of ℃,
As shown in (a), a resist film 2 having a thickness of 0.2 μm was obtained.

Next, as shown in FIG. 5B, the resist film 2 is irradiated with an electron beam 3 emitted from an EB projection exposure apparatus (accelerating voltage 100 keV) through a mask 4 to perform pattern exposure. Was done.

Next, as shown in FIG. 5C, the resist film 2 subjected to the pattern exposure is subjected to post baking 5 for 90 seconds at a temperature of 110 ° C. using a hot plate.
Was done.

Next, as shown in FIG. 6D, the post-baked resist film 2 was developed with a 2.38% tetramethylammonium hydroxide aqueous solution, and then washed with water. Then, a resist pattern 6 composed of an unexposed portion of the resist film 2 was formed.

The obtained resist pattern 6 is 4.5 μm.
The sensitivity was C / cm ² and the line and space resolution was 140 nm, and the pattern shape was also reduced, resulting in a large roundness of the surface layer of the film, which was unsatisfactory.

[Comparative Example 2] A pattern forming method according to Comparative Example 2 will be described below with reference to FIGS. 6 (a) to 6 (d).

First, a chemically amplified resist material having the following composition was prepared.

[0247]   Poly (p-hydroxystyrene / styrene / tert-butyl acrylate) ………… …………………………………………………………………………………… 6.0g   Triphenylsulfonium p-toluenesulfonate …………………… 0.3g   Dicyclohexylmethylamine ………………………………………… 0.01g   Fluorine-containing nonionic surfactant [commercial item] ……………………………… 0.1g   Propylene glycol monomethyl ether acetate ……………… 60.0g

Next, the chemically amplified resist material was filtered through a 0.1 μm membrane filter, spin-coated on the silicon substrate 1, and then prebaked at 130 ° C. for 90 seconds with a hot plate. Then, as shown in FIG. 6A, a resist film 2 having a thickness of 0.2 μm was obtained.

Next, as shown in FIG. 6B, the extreme ultraviolet rays (wavelength: 13.5) reflected by a mask (not shown) after being emitted from the extreme ultraviolet exposure device (NA: 0.1).
(nm band) 7 for pattern exposure.

Next, as shown in FIG. 6C, the resist film 2 subjected to the pattern exposure is subjected to post baking 5 for 90 seconds at a temperature of 110 ° C. using a hot plate.
Was done.

Next, as shown in FIG. 6D, the post-baked resist film 2 was developed using a 2.38% tetramethylammonium hydroxide aqueous solution, and then washed with water. Then, a resist pattern 8 composed of an unexposed portion of the resist film 2 was formed.

The obtained resist pattern 8 is 16.7.
With the sensitivity of mJ / cm ² , the line and space resolution was 150 nm, and the pattern shape was reduced and the taper shape was defective.

[Comparative Example 3] A pattern forming method according to Comparative Example 3 will be described below.

First, a chemically amplified resist material having the following composition was prepared.

[0255]   Poly (p-hydroxystyrene / styrene / tert-butyl acrylate) ………… …………………………………………………………………………………… 6.0g   Diphenyl 4-methylphenylsulfonium trifluoromethanesulfonate …………………………………………………………………………………… 0.3g   Dicyclohexylmethylamine ………………………………………… 0.01g   Fluorine-containing nonionic surfactant [commercial item] ……………………………… 0.1g   Propylene glycol monomethyl ether acetate ……………… 60.0g

Next, a resist pattern was formed using the above chemically amplified resist material in the same manner as in Comparative Example 1.

The resist pattern obtained was 6.1 μC.
With a sensitivity of / cm ² , the line and space resolution was 150 nm, and the pattern shape was also bad due to strong tailing.

[Comparative Example 4] A pattern forming method according to Comparative Example 3 will be described below.

First, a chemically amplified resist material having the following composition was prepared.

Poly (p-hydroxystyrene / styrene / tert-butyl acrylate) ………………………………………………………………………………………… ………… 6.0g Diphenyl-2,4,6-trimethylphenylsulfonium p-toluenesulfonate ………………………………………………………………………… ………… 0.3g Dicyclohexylmethylamine …………………………………… 0.01g Fluorine-containing nonionic surfactant [commercially available product] ………………………… … 0.1g Propylene glycol monomethyl ether acetate ……………… 60.0g Next, using the above chemically amplified resist material, Comparative Example 2
A resist pattern was formed in the same manner as in.

The obtained resist pattern has a length of 17.8 m.
The line and space of 140 nm could not be resolved with the sensitivity of J / cm ² , and the pattern shape was also defective in the taper shape.

[Comparative Example 5] A pattern forming method according to Comparative Example 5 will be described below.

First, a chemically amplified resist material having the following composition was prepared.

[0264]   Poly (p-hydroxystyrene / styrene / tert-butyl acrylate) ………… …………………………………………………………………………………… 6.0g   Triphenylsulfonium perfluorobutane sulfonate ………… 0.3g   Dicyclohexylmethylamine ………………………………………… 0.01g   Fluorine-containing nonionic surfactant [commercial item] ……………………………… 0.1g   Propylene glycol monomethyl ether acetate ……………… 60.0g

Next, a resist pattern was formed in the same manner as in Comparative Example 1 using the above chemically amplified resist material.

The resist pattern obtained was 8.1 μC.
With a sensitivity of / cm ² , the line and space resolution was 110 nm, and the pattern shape was poor because the film surface layer had a large roundness.

[Comparative Example 6] A pattern forming method according to Comparative Example 6 will be described below.

First, a chemically amplified resist material having the following composition was prepared.

[0269]   Poly (p-hydroxystyrene / styrene / tert-butyl acrylate) ………… …………………………………………………………………………………… 6.0g   Triphenylsulfonium perfluorooctanesulfonate: 0.3g   Dicyclohexylmethylamine ………………………………………… 0.01g   Fluorine-containing nonionic surfactant [commercial item] ……………………………… 0.1g   Propylene glycol monomethyl ether acetate ……………… 60.0g

Next, a resist pattern was formed in the same manner as in Comparative Example 2 using the above chemically amplified resist material.

The resist pattern obtained was 9.2 mJ.
The line and space resolution was 120 nm with a sensitivity of / cm ² , and the pattern shape was also poor because the film surface layer had a large roundness.

[Comparative Example 7] A pattern forming method according to Comparative Example 7 will be described below.

First, a chemically amplified resist material having the following composition was prepared.

[0274]   Poly (p-hydroxystyrene / styrene / tert-butyl acrylate) ………… …………………………………………………………………………………… 6.0g   Diphenyl-4-tert-butylphenylsulfonium perfluorooctane Honate ………………………………………………………………………… 0.3g   Dicyclohexylmethylamine ………………………………………… 0.01g   Fluorine-containing nonionic surfactant [commercial item] ……………………………… 0.1g   Propylene glycol monomethyl ether acetate ……………… 60.0g

Next, a resist pattern was formed in the same manner as in Comparative Example 1 using the above chemically amplified resist material.

The resist pattern obtained was 17.1 μm.
The sensitivity was C / cm ² , and the line and space resolution was 120 nm, and the pattern shape was poor because the film surface layer portion was stretched.

[Comparative Example 8] A pattern forming method according to Comparative Example 8 will be described below.

First, a chemically amplified resist material having the following composition was prepared.

[0279]   Poly (p-hydroxystyrene / styrene / tert-butyl acrylate) ………… …………………………………………………………………………………… 6.0g   Diphenyl-2,4,6-trimethylphenylsulfonium 4-chlorobenzenesulfo Nate ……………………………………………………………………………… 0.3g   Dicyclohexylmethylamine ………………………………………… 0.01g   Fluorine-containing nonionic surfactant [commercial item] ……………………………… 0.1g   Propylene glycol monomethyl ether acetate ……………… 60.0g

Then, a resist pattern was formed in the same manner as in Comparative Example 2 using the above chemically amplified resist material.

The obtained resist pattern is 12.3 m.
The sensitivity of J / cm ² remained at a line-and-space resolution of 140 nm, and the pattern shape was also poor because the film surface layer had a large roundness.

[Comparative Example 9] A pattern forming method according to Comparative Example 9 will be described below.

First, a chemically amplified resist material having the following composition was prepared.

[0284]   Poly (p-hydroxystyrene / styrene / tert-butyl acrylate) ………… …………………………………………………………………………………… 6.0g   Diphenyl-2,4,6-trimethylphenylsulfonium 4-trifluoromethyl ester Nense sulfonate ……………………………………………………………… 0.3g   Dicyclohexylmethylamine ………………………………………… 0.01g   Fluorine-containing nonionic surfactant [commercial item] ……………………………… 0.1g   Propylene glycol monomethyl ether acetate ……………… 60.0g

Next, a resist pattern was formed in the same manner as in Comparative Example 1 using the above chemically amplified resist material.

The obtained resist pattern was 15.9 μm.
The sensitivity of C / cm ² remained at a line-and-space resolution of 110 nm, and the pattern shape was also defective because the film surface layer portion was round.

[Comparative Example 10] A pattern forming method according to Comparative Example 10 will be described below.

First, a chemically amplified resist material having the following composition was prepared.

[0289]   Poly (p-hydroxystyrene / styrene / tert-butyl acrylate) ………… …………………………………………………………………………………… 6.0g   Diphenyl-2,4,6-trimethylphenylsulfonium 2-trifluoromethyl ester Nense sulfonate ……………………………………………………………… 0.3g   Dicyclohexylmethylamine ………………………………………… 0.01g   Fluorine-containing nonionic surfactant [commercial item] ……………………………… 0.1g   Propylene glycol monomethyl ether acetate ……………… 60.0g

Next, a resist pattern was formed using the above chemically amplified resist material in the same manner as in Comparative Example 2.

The resist pattern obtained was 13.7 m.
The sensitivity was J / cm ² and the line and space resolution was 110 nm, and the pattern shape was defective because the film surface layer was round.

[Comparative Example 11] A pattern forming method according to Comparative Example 11 will be described below.

First, a chemically amplified resist material having the following composition was prepared.

[0294]   Poly (p-hydroxystyrene / styrene / tert-butyl acrylate) ………… …………………………………………………………………………………… 6.0g   Diphenyl-4-methylphenylsulfonium perfluorooctane sulfone To …………………………………………………………………………………… 0.3g   Dicyclohexylmethylamine ………………………………………… 0.01g   Fluorine-containing nonionic surfactant [commercial item] ……………………………… 0.1g   Propylene glycol monomethyl ether acetate ……………… 60.0g

Next, a resist pattern was formed in the same manner as in Comparative Example 1 using the above chemically amplified resist material.

The resist pattern obtained was 17.5 μm.
The sensitivity of C / cm ² remained at a line-and-space resolution of 120 nm, and the pattern shape was also defective because the film surface layer portion was round.

[Comparative Example 12] A pattern forming method according to Comparative Example 12 will be described below.

First, a chemically amplified resist material having the following composition was prepared.

[0299]   Poly (p-hydroxystyrene / p-tert-butoxycarbonyloxystyrene) [Composition ratio = 67/33; Mw = 20,500; Mw / Mn = 1.10] ……………… 6.0g   Diphenyl-2,4,6-trimethylphenylsulfonium pentafluorobenzene Sulfonate …………………………………………………………………… 0.3g   Dicyclohexylmethylamine ………………………………………… 0.01g   Fluorine-containing nonionic surfactant [commercial item] ……………………………… 0.1g   Propylene glycol monomethyl ether acetate ……………… 60.0g

Then, a resist pattern was formed using the above chemically amplified resist material in the same manner as in Comparative Example 2.

The resist pattern obtained was 7.3 mJ.
With a sensitivity of / cm ² , the line and space resolution was 110 nm, and the pattern shape was poor because the film surface layer was slightly stretched.

[Comparative Example 13] A pattern forming method according to Comparative Example 13 will be described below.

First, a chemically amplified resist material having the following composition was prepared.

[0304]   Poly (p-hydroxystyrene / p-tert-butoxystyrene) [Constituent ratio = 65/3 5; Mw = 20,300; Mw / Mn = 1.10] …………………………………… 6.0g   Diphenyl-2,4,6-trimethylphenylsulfonium pentafluorobenzene Sulfonate …………………………………………………………………… 0.3g   Dicyclohexylmethylamine ………………………………………… 0.01g   Fluorine-containing nonionic surfactant [commercial item] ……………………………… 0.1g   Propylene glycol monomethyl ether acetate ……………… 60.0g

Next, a resist pattern was formed using the above chemically amplified resist material in the same manner as in Comparative Example 1.

The obtained resist pattern has a thickness of 7.7 μC.
With a sensitivity of / cm ² , the line and space resolution remained at 120 nm, and the pattern shape was also poor because the film surface layer was slightly stretched.

[Comparative Example 14] A pattern forming method according to Comparative Example 14 will be described below.

First, a chemically amplified resist material having the following composition was prepared.

[0309]   Poly (p-1-ethoxyethoxystyrene / p-hydroxystyrene / p-tert-but (Xystyrene) [constitution ratio = 24/66/10; Mw = 20,500; Mw / Mn = 1.10] …………………………………………………………………………………… 6.0g   Diphenyl-2,4,6-trimethylphenylsulfonium pentafluorobenzene Sulfonate …………………………………………………………………… 0.3g   Dicyclohexylmethylamine ………………………………………… 0.01g   Fluorine-containing nonionic surfactant [commercial item] ……………………………… 0.1g   Propylene glycol monomethyl ether acetate ……………… 60.0g

Next, a resist pattern was formed in the same manner as in Comparative Example 2 using the above chemically amplified resist material.

The resist pattern obtained was 8.2 mJ.
The line-and-space resolution was 110 nm with a sensitivity of / cm ² , and the pattern shape was almost rectangular, but the sidewall was rough and it was defective.

[Comparative Example 15] A pattern forming method according to Comparative Example 15 will be described below.

First, a chemically amplified resist material having the following composition was prepared.

Poly (p-hydroxystyrene / styrene / tert-butyl acrylate) ... 6.0 g Di- (p-tert-butylphenyl) iodonium perfluorobutane sulfonate ………………………………………… ……………………………………………… 0.3g Dicyclohexylmethylamine …………………………………… 0.01g Fluorine-containing nonionic surfactant [Commercial item] ………………………… 0.1g Propylene glycol monomethyl ether acetate ………… 60.0g Next, using the above-mentioned chemically amplified resist material, Comparative Example 1
A resist pattern was formed in the same manner as in.

The resist pattern obtained was 9.1 μC.
The sensitivity of / cm ² remained at a line-and-space resolution of 120 nm, and the pattern shape was also defective because the film surface layer portion was round.

[Comparative Example 16] A pattern forming method according to Comparative Example 15 will be described below.

First, a chemically amplified resist material having the following composition was prepared.

[0318]   Poly (p-hydroxystyrene / styrene / tert-butyl acrylate) ... 6.0g   N-trifluoromethanesulfonyloxy-5-norbornene-2,3-dicarboxyi Mido ……………………………………………………………………………… 0.3g   Dicyclohexylmethylamine ………………………………………… 0.01g   Fluorine-containing nonionic surfactant [commercial item] ……………………………… 0.1g   Propylene glycol monomethyl ether acetate ……………… 60.0g

Next, a resist pattern was formed using the above chemically amplified resist material in the same manner as in Comparative Example 2.

The resist pattern obtained was 9.6 mJ.
The line and space resolution was 130 nm with a sensitivity of / cm ² , and the pattern shape was defective because the film surface layer was round and the pattern sidewall was rough.

The following can be said as a result of verifying the above results. First, Comparative Example 1, Comparative Example 3, Comparative Examples 5 to 6 and Comparative Examples 12 to 16 had equivalent high sensitivity as compared with Examples 1 to 14, but due to defective shape or sidewall roughness. The resolution performance was quite poor. Comparative Example 2, Comparative Example 4 and Comparative Examples 7-1
The sample No. 1 is inferior to each example in terms of sensitivity, resolution and pattern shape.

Therefore, it was confirmed that according to the pattern forming method of the present invention, higher sensitivity and higher resolution can be obtained as compared with the conventional example.

Further, by comparing Examples 1 to 7 and Example 11 with Examples 8 to 10 and Examples 12 to 16, it was confirmed that the compound represented by the general formula (1) was used as an acid generator. The use of a mixture of the compound represented by the formula (2) and the compound represented by the general formula (1) is superior to the use of the compound represented by the general formula (1) alone in terms of high sensitivity and high resolution. It was proved.

[0324]

EFFECT OF THE INVENTION According to the pattern forming method of the present invention, at least one electron-withdrawing group is introduced into the meta position of the aromatic ring constituting the counter anion of the acid generator. Since the dissolution inhibitory property for the base polymer becomes high, the base polymer becomes difficult to dissolve in the alkaline developing solution in the region of the unexposed portion of the resist film which is in contact with the exposed portion. Therefore, the contrast between the solubility of the unexposed portion and the solubility of the exposed portion of the resist film is increased, and the resolution of the resist film is improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a film thickness of a resist film and line-and-space resolution in an embodiment of the present invention and a conventional example.

FIG. 2 is a diagram showing a relationship between a post-baking temperature and a line-and-space in one embodiment of the present invention and a conventional example.

3A to 3D are cross-sectional views showing respective steps of a pattern forming method according to Example 1 which embodies an embodiment of the present invention.

4A to 4D are cross-sectional views showing each step of a pattern forming method according to Example 3 embodying an embodiment of the present invention.

5A to 5D are cross-sectional views showing respective steps of a pattern forming method according to Comparative Example 1 performed to evaluate the present invention.

6A to 6D are cross-sectional views showing respective steps of a pattern forming method according to Comparative Example 2 performed to evaluate the present invention.

[Explanation of symbols]

10 Silicon substrate 11 Resist film 12 electron beams 13 masks 14 post bake 15 Resist pattern 20 Silicon substrate 21 Resist film 22 extreme ultraviolet 23 Post Bake 24 resist pattern

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H025 AA02 AB16 AC04 AC08 AD03                       BE07 BE10 BG00 BJ00 CA48                       CB14 CB17 CB41 CB55 CB56                       FA12 FA17                 2H096 AA25 BA11 EA05 FA01

Claims (13)

[Claims] 1. A base polymer whose solubility in an alkaline developing solution is changed by the action of an acid, and at least one electron-withdrawing group introduced into the meta position of an aromatic ring constituting a counter anion, which is irradiated with an energy beam. A positive chemically amplified resist material having an acid generator that generates an acid, and forming a resist film having a film thickness of 250 nm or less; an electron beam or a 1 nm band with respect to the resist film. ~ 30n
A patterning process comprising: a step of selectively irradiating an extreme ultraviolet ray having a wavelength of m band to perform pattern exposure; and a step of developing the pattern-exposed resist film to form a resist pattern. -Method of forming a cord. 2. Between the step of performing pattern exposure on the resist film and the step of developing the resist film,
The pattern forming method according to claim 1, further comprising a step of performing post-baking on the resist film at a temperature of 120 ° C. or higher and 150 ° C. or lower. 3. The pattern forming method according to claim 1, wherein the acid generator contains a compound represented by the general formula (1). [Chemical 1] (In the general formula (1), R ₂ and R ₄ are the same or different and are a hydrogen atom, a halogen atom, a nitro group or a trifluoromethyl group, and at least one of R ₂ and R ₄ is R ₁ , R ₃ and R, not hydrogen atoms
₅ is the same or different and is a hydrogen atom or a halogen atom, and R ₆ and R ₇ are the same or different and are a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. And n is an integer of 1 to 3. ) 4. In the general formula (1), R ₆ is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, and R ₇ is a linear alkyl group having 1 to 4 carbon atoms. Alternatively, it is a branched alkyl group, and the pattern forming method according to claim 3. 5. The counter anion of the compound represented by the general formula (1) is pentafluorobenzene sulfonate, 3-trifluoromethylbenzene sulfonate or 3,5-di-trifluoromethylbenzene sulfonate. The pattern forming method according to claim 3. 6. The pattern forming method according to claim 3, wherein the acid generator further contains a compound represented by the general formula (2). [Chemical 2] (In the general formula (2), R ₈ and R ₁₀ are the same or different and are a hydrogen atom, a halogen atom, a nitro group or a trifluoromethyl group, and at least one of R ₈ and R ₁₀ is R ₇ , R ₉ and R, not hydrogen atoms
₁₁ is the same or different and is a hydrogen atom or a halogen atom. ) 7. The counter anion of the compound represented by the general formula (2) is pentafluorobenzene sulfonate, 3-trifluoromethylbenzene sulfonate or 3,5-di-trifluoromethylbenzene sulfonate. The pattern forming method according to claim 6. 8. A general formula of a compound represented by the general formula (1):
7. The pattern forming method according to claim 6, wherein the weight ratio to the compound represented by (2) is 2.0 or less and 0.2 or more. 9. The compound represented by the general formula (1) is diphenyl-2,4,6-trimethylphenylsulfonium pentafluorobenzenesulfonate or diphenyl-
4-Methylphenylsulfonium pentafluorobenzene sulfonate, wherein the compound represented by the general formula (2) is triphenylsulfonium pentafluorobenzene sulfonate or triphenylsulfonium-3-trifluoromethylbenzene sulfonate. Item 7. The pattern forming method according to Item 6. 10. The base polymer comprises a first monomer unit represented by the general formula (3), a second monomer unit represented by the general formula (4), and a third monomer unit represented by the general formula (5). 4. The pattern forming method according to claim 3, further comprising: [Chemical 3] (In the general formula (3), R ₁₂ is a hydrogen atom or a methyl group.) (In the general formula (4), R ₁₃ is a hydrogen atom or a methyl group, and R ₁₄ is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms.) (In the general formula (5), R ₁₅ is a hydrogen atom or a methyl group, and R ₁₆ is an acid labile group.) 11. R ₁₆ in the general formula (5) is tert.
-Butyl group, tert-pentyl group, 1-methylcyclohexyl group, tetrahydropyranyl group, tetrahydrofuranyl group, 1-adamantyl group, 2-methyl-2-adamantyl group or 4-methyl-2-oxo-4-tetrahydropyrani group 11. The pattern forming method according to claim 10, wherein the pattern forming method is a group. 12. The pattern forming method according to claim 3, wherein the base polymer contains a compound represented by the general formula (6). [Chemical 6] (In the general formula (6), R ₁₂ is a hydrogen atom or a methyl group, R ₁₃ is a hydrogen atom or a methyl group, and R ₁₄ is a hydrogen atom or a straight or branched chain having 1 to 4 carbon atoms. An alkyl group, R ₁₅ is a hydrogen atom or a methyl group, R ₁₆
Is an acid labile group, k, l and m are all positive integers, and 0.25 ≧ l / (k + l + m) ≧ 0.10
And 0.20 ≧ m / (k + 1 + m) ≧ 0.07. ) 13. The weight average molecular weight of the base polymer is 5,000 or more and 20,000 or less, and the dispersity of the base polymer is 1.0 or more and 2.5 or less. The pattern forming method according to claim 10.