WO2018180308A1 - Chemically amplified resist material and method for forming resist pattern - Google Patents

Abstract

The purpose of the present invention is to provide a resist material which can achieve both of high sensitivity and excellent lithographic properties at high levels in a pattern formation technique utilizing a radioactive ray having a wavelength of 250 nm or less, such as EUV, electron beam, ion beam, KrF excimer laser and ArF excimer laser. The present invention is a chemically amplified resist material which can be used as the photosensitive resin composition in a lithographic process involving a partial irradiation step, a whole area irradiation step, a heating step and a developing step, and which contains (1) a base component that can be made soluble or insoluble in the developing solution by the action of an acid and (2) a component that can generate a radiation-sensitive sensitizer and an acid upon the irradiation with a radioactive ray, wherein the component (2) contains components (a) and (b) as mentioned below, or components (b) and (c) as mentioned below, or all of components (a) to (c) as mentioned below, and the component (b) contains a precursor that can be decomposed by the action of an acid to produce a compound represented by formula (A).

Description

Chemically amplified resist material and resist pattern forming method

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

EUV (extreme ultraviolet light) lithography has attracted attention as one of the elemental technologies for manufacturing next-generation semiconductor devices. EUV lithography is a pattern formation technique that uses EUV light having a wavelength of 13.5 nm as an exposure light source. According to EUV lithography, it has been demonstrated that an extremely fine resist pattern (for example, 20 nm or less) can be formed in an exposure step of a semiconductor device manufacturing process.

However, since the EUV light source developed at the present time has a low output, it takes a long time for the exposure process, and as a result, EUV lithography has not yet been put into practical use. In order to compensate for the low output of the EUV light source, it is conceivable to improve the sensitivity of the resist material (photosensitive resin composition) (see Patent Document 1). Problems similar to EUV also exist in the output and sensitivity of lithography using electron beams and ion beams as light sources.

JP 2002-174894 A

However, it has been difficult for the prior art to achieve both high sensitivity and excellent lithography properties (high resolution, low pattern roughness, etc.) at a higher level. If sensitivity can be improved while maintaining excellent lithography characteristics, not only lithography using EUV, electron beam, ion beam, etc. as a light source, but also lithography using KrF excimer laser light or ArF excimer laser light as a light source, It is possible to reduce the number of laser pulses and maintenance costs. Therefore, the present invention provides a high level of both high sensitivity and excellent lithography characteristics in pattern formation technology using radiation having a wavelength of 250 nm or less such as EUV, electron beam, ion beam, KrF excimer laser, ArF excimer laser, etc. An object of the present invention is to provide a resist material that can be achieved. Another object of the present invention is to provide a resist pattern forming method using the resist material.

The invention made in order to solve the above problems includes a step of irradiating a part of a resist film formed using a photosensitive resin composition with a first radiation having a wavelength of 250 nm or less, and the partial irradiation. A step of irradiating the entire surface of the resist film after the step with a second radiation having a wavelength exceeding 250 nm, a step of heating the resist film after the entire surface irradiation step, and developing the resist film after the heating step with a developer A chemically amplified resist material used as the photosensitive resin composition, wherein (1) a base component that is soluble or insoluble in the developer by the action of an acid; 2) a radiation-sensitive sensitizer and a component that generates an acid upon irradiation, and the component (2) includes the following components (a) and (b), the following components (b) and (c), or A chemically amplified resist material containing all of the components (a) to (c), wherein the component (b) is decomposed by the action of an acid to produce a compound represented by the following formula (A): is there.
(A) In the non-irradiation part that generates the acid and the radiation-sensitive sensitizer that absorbs the second radiation by the irradiation of the first radiation and is not irradiated with the first radiation in the partial irradiation step, Radiation-sensitive acid-sensitizer generator that does not substantially generate the acid and radiation-sensitive sensitizer upon irradiation with the second radiation (b) Radiation-sensitive that absorbs the second radiation upon irradiation with the first radiation In the non-irradiated part that generates the photosensitizer and is not irradiated with the first radiation in the partial irradiation step, the radiation-sensitive sensitizer is not substantially generated by the irradiation of the second radiation. Body generator (c) In the non-irradiated part where the first radiation is not irradiated with the first radiation and the acid is substantially generated by the second radiation. Does not cause radiation sensitive acid generator

(In the formula (A), R ^a to R ^d are each independently a hydrogen atom, an amino group, a sulfanyl group, a halogen atom, or a monovalent organic group having 1 to 20 carbon atoms, and R ¹ to R ⁶ Each independently represents a hydrogen atom, a hydroxy group, an amino group, a sulfanyl group, a halogen atom or a monovalent organic group having 1 to 20 carbon atoms, or R ^a to R ^d and R ¹ to R ⁶ . 2 or more of them are part of a ring structure having 4 to 20 ring members constituted with a carbon chain to which they are bonded to each other, provided that at least one of R ¹ to R ⁶ is a hydroxy group .)

Another invention made to solve the above problems is (1) a base component that is soluble or insoluble in a developer by the action of an acid, and (2) a radiation-sensitive sensitizer and an acid generated by irradiation. The component (2) contains the components (a) and (b), the components (b) and (c), or the components (a) to (c), The component (b) is a chemically amplified resist material containing a precursor that decomposes by the action of an acid to produce a compound represented by the above formula (A).

Still another invention made in order to solve the above-mentioned problems is a step of coating the chemically amplified resist material on a substrate, and a wavelength of 250 nm or less on a part of the resist film formed by the coating step. A step of irradiating radiation having, a step of irradiating the entire surface of the resist film after the partial irradiation step with radiation having a wavelength exceeding 250 nm, a step of heating the resist film after the whole surface irradiation step, and the heating step And a step of developing the subsequent resist film.

Here, “the acid and radiation-sensitive sensitizer are not substantially generated by the irradiation of the second radiation in the non-irradiated portion where the first radiation is not irradiated in the partial irradiation step”, “the partial irradiation step In the non-irradiated part that is not irradiated with the first radiation, the radiation sensitive sensitizer is not substantially generated by the irradiation of the second radiation. " , The acid is not substantially generated by the irradiation of the second radiation ”,“ when the first radiation is not irradiated and only the second radiation is irradiated, the acid and the radiation-sensitive sensitizer are not substantially generated ”. "When the second radiation is not irradiated and only the second radiation is not emitted, the above-mentioned radiation-sensitive sensitizer is not substantially generated" and "When the first radiation is not irradiated and only the second radiation is irradiated" "The acid is not substantially generated" means that the second release. Irradiation part in partial irradiation even when acid or radiation-sensitive sensitizer is not generated by irradiation of only rays or acid or radiation-sensitive sensitizer is generated by irradiation of second radiation only Acid and radiation sensitive sensitization by irradiation of the second radiation in the non-irradiated part to such an extent that the difference in concentration of the acid and radiation sensitive sensitizer between the non-irradiated part and the non-irradiated part can be maintained to a level that allows pattern formation. As a result, the amount of the photosensitive member generated is small, and as a result, only one of the above-mentioned partially irradiated portion or non-partially irradiated portion (that is, the portion not irradiated with radiation at the time of partial irradiation) is used as a developer. This means that the amount of acid or radiation-sensitive sensitizer generated is small enough to be dissolved. “Organic group” refers to a group containing at least one carbon atom. “Number of ring members” means the number of atoms constituting the ring of an aromatic ring structure, aromatic heterocyclic structure, alicyclic structure and aliphatic heterocyclic structure. In the case of a polycyclic ring structure, this polycyclic ring The number of atoms to be played.

According to the present invention, in pattern formation technology using radiation having a wavelength of 250 nm or less, such as EUV light, electron beam, ion beam, KrF excimer laser, ArF excimer laser, etc., both high sensitivity and excellent lithography characteristics are enhanced. There is provided a chemically amplified resist material that can achieve the standard. Moreover, according to this invention, the resist pattern formation method using the said resist material is provided.

Hereinafter, embodiments of the present invention will be described in detail. In addition, this invention is not limited to the following embodiment.

<Chemically amplified resist material>
The chemically amplified resist material according to this embodiment is used as a photosensitive resin composition in a two-step exposure lithography process. The two-step exposure lithography process includes a partial irradiation step, a full-surface irradiation step, a heating step, and a development step. In the partial irradiation step, the first radiation having a wavelength of 250 nm or less is irradiated. In the entire surface irradiation step, the second radiation having a wavelength exceeding 250 nm is irradiated.

The chemically amplified resist material according to the present embodiment may be either a positive resist material or a negative resist material, and is appropriately selected by selecting a base component, a developer, and the like described later. Here, a resist material in which a part of the irradiated part is melted by development after part of the irradiation and a non-partially irradiated part (light-shielding part) remains is called a positive resist material. The resist material that melts and remains irradiated is called negative resist.

The chemically amplified resist material according to the present embodiment (hereinafter, simply referred to as “resist material”) includes (1) a base component that becomes soluble or insoluble in a developer by the action of an acid, and (2) sensitization by radiation irradiation. A radiation sensitizer and an acid generating component.

<(1) Base component>
In the present embodiment, the base component (1) may be an organic compound or an inorganic compound. The organic compound may be a high molecular compound or a low molecular compound. In addition, the polymer compound may be a polymer whose solubility in a developer is changed by the action of an acid. Such a polymer is widely used as a base component of a resist material. Furthermore, (1) it is desirable that the base component does not excessively absorb the first radiation in the partial irradiation and can realize the formation of a resist pattern having a sufficiently high verticality. In addition, it is desirable that (1) the base component has a low absorption of the second radiation in the entire surface irradiation and is unlikely to induce an unnecessary sensitization reaction in the non-irradiated part during the entire surface irradiation.

The lower limit of the weight average molecular weight (Mw) of the polymer is preferably 1,000, more preferably 3,000, and more preferably 5,000. The upper limit of the Mw is preferably 200,000, more preferably 50,000, and still more preferably 10,000. The upper limit of the ratio of Mw to the number average molecular weight (Mn) of the polymer is preferably 5, more preferably 3, and even more preferably 2.2. The lower limit of the above ratio is usually 1 and preferably 1.5. In the above-mentioned polymer, a part of the irradiated portion becomes soluble or insoluble in the developing solution in the developing step due to an acid catalyst reaction during the heating step after the entire surface irradiation.

In this specification, Mw and Mn of the polymer are GPC columns (two "G2000HXL", one "G3000HXL", one "G4000HXL" manufactured by Tosoh Corporation), a flow rate of 1.0 mL / min, and an elution solvent tetrahydrofuran. , Measured by gel permeation chromatography (GPC) using a monodisperse polystyrene as a standard, using a differential refractometer as a detector under the analysis conditions of a sample concentration of 1.0 mass%, a sample injection amount of 100 μL, and a column temperature of 40 ° C. Is the value to be

Examples of the polymer whose solubility in the developing solution is changed by the action of the acid include, for example, a polymer having a structural unit containing a polar group (for example, an acidic functional group), a polymer having a structural unit containing an acid dissociable group, etc. Is mentioned. A polymer having a structural unit containing a polar group is soluble in an alkali developer, but becomes insoluble in an alkali developer by reacting with a crosslinking agent described later in the heating step by the action of an acid. In this case, in the development process, the resist film in the non-partially irradiated portion can be removed with an alkaline developer. Therefore, when the resist film formed using the polymer is developed with an alkaline developer, the resist material functions as a negative resist material.

On the other hand, the polymer having a structural unit containing an acid dissociable group is soluble in an organic developer, but insoluble or hardly soluble in an alkali developer. The polymer having a structural unit containing an acid-dissociable group is removed from the acid-dissociable group by the action of an acid in the heating step (deprotection), imparted polarity, soluble in an alkali developer and soluble in an organic developer. Insoluble. In this case, the resist film in the non-partially irradiated portion can be removed with an organic developer, and the partially irradiated portion can be removed with an alkali developer. Therefore, when a resist film formed using the above polymer is developed with an organic developer, the resist material functions as a negative resist material. On the other hand, when a resist film formed using the above polymer is developed with an alkaline developer, the resist material functions as a positive resist material.

[Polymer having a structural unit containing an acid-dissociable group]
A polymer having a structural unit containing an acid dissociable group (hereinafter also referred to as “structural unit (I)”) (hereinafter also referred to as “[P] polymer”) has a lactone structure in addition to the structural unit (I). , A structural unit (II) including a cyclic carbonate structure, a sultone structure or a combination thereof, a structural unit (III) including an aromatic ring to which a hydroxy group is bonded, and a structural unit including a group represented by the formula (Y) described later ( IV) and other structural units other than the structural units (I) to (IV).

(Structural unit (I))
The structural unit (I) is a structural unit containing an acid dissociable group. Examples of the structural unit (I) include a structural unit represented by the following formula (X).

In the formula (X), R ^W is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ^X is a monovalent hydrocarbon group having 1 to 20 carbon atoms. R ^Y and R ^Z are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, or a ring member having 3 to 3 ring atoms composed of these groups together with the carbon atom to which they are bonded. It is a part of 20 alicyclic structures.

The “hydrocarbon group” includes a chain hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. The “hydrocarbon group” may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. The “chain hydrocarbon group” refers to a hydrocarbon group that does not include a cyclic structure but includes only a chain structure, and includes both a linear hydrocarbon group and a branched hydrocarbon group. The term “alicyclic hydrocarbon group” refers to a hydrocarbon group that includes only an alicyclic structure as a ring structure and does not include an aromatic ring structure, and includes a monocyclic alicyclic hydrocarbon group and a polycyclic alicyclic group. Includes both hydrocarbon groups. However, it is not necessary to be composed only of the alicyclic structure, and a part thereof may include a chain structure. “Aromatic hydrocarbon group” refers to a hydrocarbon group containing an aromatic ring structure as a ring structure. However, it is not necessary to be composed only of an aromatic ring structure, and a part thereof may include a chain structure or an alicyclic structure.

The R ^W, preferably a hydrogen atom or a methyl group, more preferably a methyl group.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ^X , R ^Y and R ^Z include a monovalent chain hydrocarbon group having 1 to 20 carbon atoms and a monovalent hydrocarbon group having 3 to 20 carbon atoms. And alicyclic hydrocarbon groups, monovalent aromatic hydrocarbon groups having 6 to 20 carbon atoms, and the like.

Examples of the monovalent chain hydrocarbon group having 1 to 20 carbon atoms include alkyl groups such as methyl group, ethyl group, n-propyl group and i-propyl group, alkenyl groups such as ethenyl group, propenyl group and butenyl group. Alkynyl groups such as ethynyl group, propynyl group, butynyl group and the like.

Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include monocyclic alicyclic saturated hydrocarbon groups such as cyclopentyl group and cyclohexyl group, and monocyclic alicyclic hydrocarbon groups such as cyclopentenyl group and cyclohexenyl group. Polycyclic alicyclic unsaturated groups such as polycyclic alicyclic saturated hydrocarbon groups such as cyclic unsaturated hydrocarbon groups, norbornyl groups, adamantyl groups, and tricyclodecyl groups, norbornenyl groups, and tricyclodecenyl groups A hydrocarbon group etc. are mentioned.

Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms include aryl groups such as phenyl group, tolyl group, xylyl group, naphthyl group and anthryl group, benzyl group, phenethyl group, naphthylmethyl group and anthrylmethyl group. And an aralkyl group such as a group.

Examples of the alicyclic structure having 3 to 20 ring members composed of R ^Y and R ^Z combined with the carbon atom to which they are bonded include a cyclopentane structure, a cyclohexane structure, a norbornane structure, an adamantane structure, and the like.

The structural unit (I) is preferably a structural unit derived from 1-alkylcycloalkane-1-yl (meth) acrylate.

As a minimum of the content rate of structural unit (I), 20 mol% is preferred to 40 mol% with respect to all the structural units which constitute a [P] polymer. As an upper limit of the said content rate, 80 mol% is preferable and 60 mol% is more preferable.

(Structural unit (II))
The structural unit (II) is a structural unit including a lactone structure, a cyclic carbonate structure, a sultone structure, or a combination thereof. When the [P] polymer has the structural unit (II), the solubility in the developer can be made more appropriate.

As the structural unit (II), for example, a structural unit derived from butyrolactone-yl (meth) acrylate, a structural unit derived from norbornanelactone-yl (meth) acrylate, a structural unit derived from ethylene carbonate-ylmethyl (meth) acrylate, And structural units derived from norbornane sultone-yl (meth) acrylate.

When the [P] polymer has the structural unit (II), the lower limit of the content ratio of the structural unit (II) is preferably 20 mol%, more preferably 30 mol%. As an upper limit of the said content rate, 80 mol% is preferable and 70 mol% is more preferable.

(Structural unit (III))
The structural unit (III) is a structural unit including an aromatic ring to which a hydroxy group is bonded. When the [P] polymer has the structural unit (III), the sensitivity in partial irradiation of the resist material can be further improved.

Examples of the structural unit (III) include a structural unit derived from hydroxystyrene, a structural unit derived from hydroxyvinylnaphthalene, and a structural unit derived from hydroxyphenyl (meth) acrylate.

When the [P] polymer has the structural unit (III), the lower limit of the content ratio of the structural unit (III) is preferably 20 mol%, more preferably 30 mol%. As an upper limit of the said content rate, 80 mol% is preferable and 70 mol% is more preferable.

(Structural unit (IV))
The structural unit (IV) is a structural unit containing a group represented by the following formula (Y). When the [P] polymer has the structural unit (IV), the sensitivity in partial irradiation of the resist material can be further improved.

In the above formula (Y), R ^P and R ^Q are each independently a fluorine atom or a fluorinated alkyl group having 1 to 10 carbon atoms.

The fluorinated alkyl group having 1 to 10 carbon atoms represented by R ^P and R ^Q, for example, fluoromethyl group, difluoromethyl group, trifluoromethyl group, pentafluoroethyl group, heptafluoropropyl group, a nonafluorobutyl group Etc. Of these, a trifluoromethyl group is preferred.

When the [P] polymer has a structural unit (IV), the lower limit of the content ratio of the structural unit (IV) is preferably 5 mol%, and more preferably 10 mol%. As an upper limit of the said content rate, 50 mol% is preferable and 30 mol% is more preferable.

The lower limit of the molecular weight of the low molecular compound is preferably 300, more preferably 500. The upper limit of the molecular weight is preferably 3,000, and more preferably 2,000. The low molecular weight compound is such that a part of the irradiated portion becomes soluble or insoluble in the developer in the development step due to an acid catalyst reaction in the heating step after the entire surface irradiation.

Examples of the low molecular weight compound include star-shaped molecules such as torquesen derivatives, calixarene derivatives, Noria, dendrimers and the like.

Examples of the inorganic compound include metal oxides such as cobalt oxide, hafnium oxide, and zirconium oxide, and organometallic compounds such as complexes. The metal oxide may be in the form of particles or nanoparticles having a nano-order particle size. The metal oxide particles may be coordinated with a carboxylic acid or the like. (1) An example of a change in solubility when an inorganic compound is used as the base component is shown below. For example, when (1) a metal oxide nanoparticle coordinated with a carboxylic acid is used as a base component, an anion of an acid generated by radiation irradiation coordinates to the metal oxide instead of the carboxylate anion. As a result, the interaction between the metal oxide particles increases, (1) the base component gels, and dissolution of the irradiated portion when only the non-irradiated portion is dissolved in the development step can be suppressed.

<(2) A component that generates a radiation-sensitive sensitizer and an acid upon irradiation>
The said component is a component which generate | occur | produces a radiation sensitive sensitizer and an acid by irradiation (exposure). The above components include (a) a radiation sensitive acid-sensitizer generator, (b) a radiation sensitive sensitizer generator, and (c) a radiation sensitive acid generator. Component, any two components in components (a) to (c), or all of components (a) to (c). That is, in the resist material, the component (2) is blended with the base component (1). Further, (a) a radiation-sensitive acid-sensitizer generator, (b) a radiation-sensitive sensitizer generator, and (c) a radiation-sensitive acid generator may be an acid and a sensitizer even if they are low molecular compounds. It may be a polymer having a group that generates a sensitizer, a polymer having a group that generates a sensitizer, or a polymer having a group that generates an acid.

[(A) Radiation sensitive acid-sensitizer generator]
(A) The radiation-sensitive acid-sensitizer generating agent generates an acid and a radiation-sensitive sensitizer that absorbs the second radiation by the irradiation of the first radiation, and the first irradiation in the partial irradiation step. In the non-irradiated part where no radiation is irradiated, the acid and the radiation-sensitive sensitizer are not substantially generated by the irradiation of the second radiation. Since the (a) radiation-sensitive acid-sensitizer generator has the above properties, the generation of the acid and the radiation-sensitive sensitizer due to the irradiation of the second radiation in the entire surface irradiation step can be suppressed.

Further, (a) when an acid and a radiation-sensitive sensitizer are generated by irradiating the radiation-sensitive acid-sensitizer generating agent with the second radiation, the irradiation part and the non-irradiation part in partial irradiation The amount of acid and radiation-sensitive sensitizer generated by the irradiation of the second radiation can be reduced to such an extent that the difference in concentration between the acid and radiation-sensitive sensitizer can be maintained at a level that allows pattern formation. As a minimum of the wavelength of the 2nd radiation, 300 nm is preferred, 320 nm is more preferred, and 350 nm is still more preferred. (A) When the radiation-sensitive acid-sensitizer generating agent generates an acid and a radiation-sensitive sensitizer by irradiation with the second radiation, the wavelength of the second radiation is set to be not less than the above lower limit, whereby the first radiation In the partially irradiated part irradiated with acid, acid is generated during the irradiation of the second radiation due to the sensitizing action of the generated radiation-sensitive sensitizer, and on the contrary, in the non-partially irradiated part where the first radiation is not irradiated, the second is irradiated. Generation of acid during irradiation with radiation is suppressed. As a result, the sensitivity and contrast between the partially irradiated portion and the non-partially irradiated portion can be improved.

(A) Examples of the radiation-sensitive acid-sensitizer generator include onium salt compounds, diazomethane compounds, and sulfonimide compounds. Examples of the onium salt compound include a sulfonium salt compound, a tetrahydrothiophenium salt compound, and an iodonium salt compound. Examples of the (a) radiation-sensitive acid-sensitizer generator which is a sulfonium salt compound include compounds having a carbon atom adjacent to S ⁺ and having a hydroxy group bonded to the carbon atom.

[(B) Radiation-sensitive sensitizer generating agent]
(B) The radiation-sensitive sensitizer generating agent generates a radiation-sensitive sensitizer that absorbs the second radiation when irradiated with the first radiation, and the first radiation is not irradiated in the partial irradiation step. The irradiation part is a component that does not substantially generate the radiation-sensitive sensitizer when irradiated with the second radiation, and is different from the radiation-sensitive acid-sensitizer generating agent (a). In the pattern forming method according to the present embodiment, the chemical structure of (b) the radiation-sensitive sensitizer generating agent is converted by a direct or indirect reaction in the partial irradiation process, and acid generation is assisted in the entire irradiation process. To produce a radiation sensitive sensitizer. The peak of the wavelength of the absorbed radiation is partially shifted before and after the irradiation process, so that the absorption of the second radiation in the entire irradiation process is performed between the irradiated part and the non-irradiated part where the radiation sensitive sensitizer is generated. Contrast can be easily obtained. Furthermore, when the peak shift of the absorption wavelength is large, the contrast of the absorption of the second radiation in the entire surface irradiation process becomes larger.

In addition, (b) when the radiation-sensitive sensitizer is generated by irradiating the radiation-sensitive sensitizer generating agent with the second radiation, the radiation sensitivity between the irradiated portion and the non-irradiated portion in the partial irradiation. As a lower limit of the wavelength of the second radiation that can reduce the amount of radiation-sensitive sensitizer generated by irradiation of the second radiation to such an extent that the difference in concentration of the photosensitive sensitizer can be maintained at a size that allows pattern formation, 300 nm is preferable, 320 nm is more preferable, and 350 nm is more preferable. (B) When the radiation-sensitive sensitizer generating agent generates a radiation-sensitive sensitizer by irradiation of the second radiation, the first radiation is irradiated by setting the wavelength of the second radiation to the above lower limit or more. In the partial irradiation section, acid is generated during the irradiation of the second radiation due to the sensitizing action of the generated radiation-sensitive sensitizer, and conversely, in the non-partial irradiation section where the first radiation is not irradiated, the second radiation is irradiated. Generation of acid in is suppressed. As a result, the sensitivity and contrast between the partially irradiated portion and the non-partially irradiated portion can be improved.

(B) As a radiation sensitive sensitizer generating agent, what becomes the compound (carbonyl compound) which has a carbonyl group which absorbs the 2nd radiation in a whole surface irradiation process by irradiation of the 1st radiation in a partial irradiation process is preferable. . Examples of the carbonyl compound include aldehydes, ketones, carboxylic acids and carboxylic acid esters. Due to the above reaction, the peak of the absorption wavelength of radiation occurs only in the radiation-sensitive sensitizer generating agent (b) of the partially irradiated part. Therefore, after partial irradiation, if the entire surface is irradiated with radiation having a wavelength that can be absorbed only by the partial irradiation portion, only the partial irradiation portion can be selectively sensitized.

The (b) radiation-sensitive sensitizer generator is a precursor (hereinafter referred to as “(A) sensitizer”) that is decomposed by the action of an acid and is represented by the following formula (A). , Also referred to as “[B] precursor”). (B) When the radiation-sensitive sensitizer generator contains the [B] precursor, (a) a radiation-sensitive acid-sensitizer generator or (c) generation of a radiation-sensitive acid in a partially irradiated part. By the action of the acid generated from the agent, a radiation-sensitive sensitizer can be generated efficiently and a good fine pattern can be formed.

((A) sensitizer)
(A) A sensitizer is a compound represented by the following formula (A).

In the above formula (A), R ^a to R ^d are each independently a hydrogen atom, an amino group, a sulfanyl group, a halogen atom or a monovalent organic group having 1 to 20 carbon atoms, and R ¹ to R ⁶ Each independently represents a hydrogen atom, a hydroxy group, an amino group, a sulfanyl group, a halogen atom or a monovalent organic group having 1 to 20 carbon atoms, or R ^a to R ^d and R ¹ to R ⁶ . Two or more of them are part of a ring structure having 4 to 20 ring members that is formed together with the carbon chain to which they are bonded. However, at least one of R ¹ to R ⁶ is a hydroxy group.

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by R ^a to R ^d and R ¹ to R ⁶ include a monovalent hydrocarbon group having 1 to 20 carbon atoms, carbon- A group (α) containing a divalent heteroatom-containing group between carbons, a group obtained by substituting a part or all of the hydrogen atoms of the monovalent hydrocarbon group and the group (α) with a monovalent heteroatom-containing group Etc.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms are the same as those exemplified as the monovalent hydrocarbon group having 1 to 20 carbon atoms of R ^X , R ^Y and R ^Z in the above formula (X). Groups and the like.

Examples of the hetero atom constituting the monovalent and divalent heteroatom-containing group include an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, a silicon atom, and a halogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

Examples of the divalent heteroatom-containing group include —O—, —CO—, —S—, —CS—, —NR′—, a group in which two or more of these are combined, and the like. R 'is a hydrogen atom or a monovalent hydrocarbon group.

Examples of the monovalent heteroatom-containing group include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom, hydroxy group, carboxy group, cyano group, amino group and sulfanyl group.

Examples of the ring structure having 4 to 20 ring members constituted by a carbon chain in which two or more of R ^a to R ^d and R ¹ to R ⁶ are combined with each other include, for example, naphthalene structure, anthracene structure, fluorene Examples include a structure, a carbocyclic structure such as a dibenzocyclohexane structure, a xanthene structure, a thioxanthene structure, a dibenzothiacyclohexane structure, and a heterocyclic structure such as a dibenzoazacyclohexane structure.

The (A) a sensitizer, those R ² in the formula (A) is a hydroxy group. (A) a sensitizer, when R ² is a hydroxy group, a sensitizing performance is improved, the sensitivity of the resist material is further improved.

(A) As the sensitizer, it is preferable that at least two of R ¹ to R ^{6 in} the above formula (A) are hydroxy groups. (A) When two or more of R ¹ to R ⁶ are hydroxy groups in the sensitizer, the sensitization performance is further improved, and the sensitivity of the resist material is further improved.

(A) The number of hydroxy groups bonded to the aromatic ring of the sensitizer is preferably 1 to 3, more preferably 1 and 2, and even more preferably 2.

In addition, it is preferable that a hydroxyl group is not bonded to a carbon atom (ortho-position carbon atom) on the same aromatic ring adjacent to the carbon on the aromatic ring to which the carbonyl group of the sensitizer is bonded. . The reason for this will be described below.

The sensitizer transits from the ground singlet state to the excited singlet state by irradiation with the second radiation. However, the excited singlet state has a very short lifetime and is in nanosecond units, and the probability of donating energy or electrons from this singlet state to the photoacid generator or the like is very low.

On the other hand, if the sensitizer can transition from the excited singlet state to the excited triplet state by a behavior called intersystem crossing, the lifetime of this excited triplet state is relatively long, in units of microseconds. Probability of donating energy or electrons to the generating agent is greatly improved.

This intersystem crossing is known to occur easily between excited states having different transition characteristics. Since benzophenone has an excited singlet state in an n orbital and an excited triplet state in a π * orbital, the transition is n−. π * transition, and inter-term crossing is very likely to occur (El-Sayed rule). Therefore, as generally known, benzophenone functions as a good sensitizer.

However, in a benzophenone derivative, when a hydroxyl group is bonded to a carbon atom (ortho-position carbon atom) on the same aromatic ring adjacent to the carbon on the aromatic ring to which the carbonyl group is bonded, the energy level of the n orbital decreases. As a result, the excited singlet state becomes a π orbit, and the transition from the excited singlet state to the excited triplet state becomes a π-π * transition, so that intersystem crossing hardly occurs, and as a sensitizer. It becomes difficult to function.

Examples of (A) sensitizers include compounds represented by the following formulas (i-1) to (i-24) (hereinafter also referred to as “compounds (i-1) to (i-24)”) and the like. Can be mentioned.

(A) As the sensitizer, compounds (i-1) to (i-6) are preferable, and compounds (i-1) and (i-2) are more preferable.

([B] precursor)
[B] The precursor is a compound that is decomposed by the action of an acid to yield a compound (A). [B] Examples of the precursor include an esterified product and an acetalized product of the compound (A), and an acetalized product of the compound (A) is preferable. [B] When the precursor is an acetalized product, decomposition due to the action of an acid is more likely to occur, and as a result, the sensitivity of the resist material is further improved.

Examples of the esterified product of the compound (A) include compounds in which a hydrogen atom of a hydroxy group bonded to a benzene ring is substituted with an acyl group.

Examples of the acetalized compound (A) include a compound obtained by acetalizing a keto group, a compound having an acetal structure derived from two hydroxy groups located at the ortho position of a benzene ring, and two compounds bonded to aromatic rings of different molecules. Examples thereof include a compound having an acetal structure derived from a hydroxy group. Among these, from the viewpoint of ease of synthesis of the acetalized product, a compound obtained by acetalizing a keto group, a compound having an acetal structure derived from two hydroxy groups located at the ortho position of the benzene ring, and a keto group are acetalized. A compound having both the above structure and an acetal structure derived from two hydroxy groups located at the ortho position of the benzene ring is preferred.

Examples of the [B] precursor include compounds represented by the following formulas (B-1) to (B-4) (hereinafter also referred to as “compounds (B-1) to (B-4)”) and the like. It is done.

In the above formulas (B-1) to (B-4), R ^a to R ^d are each independently a hydrogen atom, an amino group, a sulfanyl group, a halogen atom or a monovalent organic group having 1 to 20 carbon atoms. R ¹ to R ⁶ are each independently a hydrogen atom, a hydroxy group, an amino group, a sulfanyl group, a halogen atom, or a monovalent organic group having 1 to 20 carbon atoms, or R ^a to R 6 Two or more of ^d and R ¹ to R ⁶ are part of a ring structure having 4 to 20 ring members that is formed together with the carbon chain to which they are bonded to each other. R ^A and R ^B are each independently a monovalent organic group having 1 to 20 carbon atoms, or the number of ring members formed together with O—C—O in which these groups are combined with each other. Part of 4-20 ring structures. R ^C and R ^D each independently represent a monovalent organic group having 1 to 20 carbon atoms, or have 3 to 20 ring members composed of these groups together with the carbon atom to which they are bonded. Part of the ring structure.

The groups represented by R ^a to R ^d and R ¹ to R ⁶ in the above formulas (B-1) to (B-4) and the ring structure formed by these groups include R ^{a in the} above formula (A). ~ include the same ones such as those exemplified as R ^d and group or ring structure represented by R ^{1 -} R ^6.

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by R ^A and R ^B and R ^C and R ^D include, for example, R ^a to R ^d and R ¹ to R ^{6 in} the above formula (A). Examples thereof include the same groups as those exemplified as 1 to 20 monovalent organic groups.

R ^A and R ^B are preferably chain hydrocarbon groups, more preferably alkyl groups, and even more preferably methyl groups.

Examples of the ring structure having 4 to 20 ring members constituted by O—C—O in which R ^A and R ^B groups are combined with each other include, for example, 1,3-dioxacyclopentane structure, 1,3- Examples include 1,3-dioxacycloalkane structures such as dioxacyclohexane structures. Of these, a 1,3-dioxacyclopentane structure is preferable.

R ^C and R ^D are preferably chain hydrocarbon groups, more preferably alkyl groups, and even more preferably methyl groups.

Examples of the ring structure having 3 to 20 ring members constituted by the carbon atoms to which the groups R ^C and R ^D are combined with each other include cycloalkane structures such as a cyclopentane structure and a cyclohexane structure.

[B] Examples of the precursor include compounds represented by the following formulas (B-1-a), (B-2-a), (B-3-a), and (B-4-a) (hereinafter, “Compounds (B-1-a), (B-2-a), (B-3-a), also referred to as (B-4-a)”).

Of these, compounds (B-1-a), (B-2-a) and (B-4-a) are preferred.

([B] precursor synthesis method)
[B] The precursor can be synthesized by performing an acetalization or esterification reaction using a hydroxyl group bonded to the keto group and / or aromatic ring of the (A) sensitizer.

(A) As an acetalizing agent (1a) for converting a keto group of a sensitizer into a chain acetal structure such as a dimethyl acetal structure, for example, trialkyl orthoformate such as trimethyl orthoformate and triethyl orthoformate, orthoacetic acid Ortho esters such as trialkyl orthoacetate such as trimethyl, triethyl orthoacetate and the like can be mentioned. (A) As the acetalizing agent (1b) for converting the keto group of the sensitizer into a cyclic acetal structure such as a 1,3-dioxacyclopentane structure, for example, ortho such as a mixture of trimethyl orthoformate and ethylene glycol Examples thereof include a mixture of an ester and vicinal diol.

(A) As the acetalizing agent (2) for converting two hydroxy groups located at the ortho position of the benzene ring of the sensitizer into an acetal structure, for example, 2,2-dimethoxypropane, 2,2-diethoxy Examples include acetals of ketones having 1 to 20 carbon atoms such as propane, 3,3-dimethoxypentane, and 1,1-dimethoxycyclohexane.

Compounds (B-1) and (B-4) are prepared by using, for example, the acetalizing agent (1a) and / or (1b) for the sensitizer (A) in the presence of an acid such as p-toluenesulfonic acid. It can be synthesized by carrying out an acetalization reaction.

Compound (B-2) uses an acetalizing agent (2), for example, for the sensitizer (A) having two hydroxy groups located at the ortho positions of the benzene ring, and an acid such as p-toluenesulfonic acid is present. It can synthesize | combine by performing acetalization reaction under.

Compound (B-3) comprises an acetalizing agent (1a) and / or (1b) and an acetalizing agent (2) for the sensitizer (A) having two hydroxy groups located at the ortho positions of the benzene ring. ) And an acetalization reaction in the presence of an acid such as p-toluenesulfonic acid.

In the acetalization reaction, a solvent such as toluene may be used. The compounds (B-1) to (B-4) can be isolated by appropriately purifying the obtained product by column chromatography, recrystallization, distillation or the like. [B] precursors other than those described above can also be synthesized by the same method as described above.

[(C) Radiation sensitive acid generator]
(C) The radiation-sensitive acid generator generates acid upon irradiation with the first radiation, and the non-irradiated portion where the first radiation is not irradiated in the partial irradiation step causes the acid to be generated upon irradiation with the second radiation. It is a component that does not substantially occur and is different from the above-mentioned (a) radiation-sensitive acid-sensitizer generator. (C) Since the radiation-sensitive acid generator has the above properties, an acid can be generated only at a part of the resist film irradiated by a radiation sensitization reaction during the entire surface irradiation.

In addition, (c) when acid is generated by irradiating the radiation sensitive acid generator with the second radiation, it is possible to pattern the difference in acid concentration between the irradiated part and non-irradiated part in partial irradiation The lower limit of the wavelength of the second radiation that can reduce the amount of acid generated by the irradiation of the second radiation to such an extent that the size can be maintained is preferably 300 nm, more preferably 320 nm, and even more preferably 350 nm. (C) When the radiation-sensitive acid generator generates an acid upon irradiation with the second radiation, the wavelength of the second radiation is set to be equal to or higher than the lower limit, so that it is generated in the partial irradiation unit irradiated with the first radiation. Due to the sensitizing action of the radiation-sensitive sensitizer, acid is generated during the irradiation of the second radiation, and conversely, in the non-partially irradiated portion where the first radiation is not irradiated, the generation of acid during the irradiation of the second radiation is suppressed. The As a result, the sensitivity and contrast between the partially irradiated portion and the non-partially irradiated portion can be improved.

(C) Examples of the radiation sensitive acid generator include onium salt compounds, diazomethane compounds, N-sulfonyloxyimide compounds and the like. Examples of the onium salt compound include a sulfonium salt compound, a tetrahydrothiophenium salt compound, and an iodonium salt compound. (C) As the radiation-sensitive acid generator, sulfonium salt compounds, iodonium salt compounds, sulfonyldiazomethane, N-sulfonyloxyimide, and oxime-O-sulfonate type radiation-sensitive acid generators are preferred, and sulfonium salt compounds and iodonium. A salt compound is more preferable.

Examples of the sulfonium salt compounds include triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, triphenylsulfonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2, 2-tetrafluoroethanesulfonate, 4-cyclohexylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium 2-bicyclo [2.2 .1] Hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium 1,2-di (cyclohexyl) Oxycarbonyl) ethane-1-sulfonate, and the like.

Examples of the tetrahydrothiophenium salt compound include 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium. Nonafluoro-n-butanesulfonate and the like can be mentioned.

Examples of the iodonium salt compound include diphenyliodonium trifluoromethanesulfonate, bis (4-tert-butylphenyl) iodonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethane. Examples include sulfonates.

Examples of N-sulfonyloxyimide compounds include N- (trifluoromethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (nonafluoro-n-butanesulfonyloxy). ) Bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide and the like.

Examples of the diazomethane compound include bis (n-propylsulfonyl) diazomethane and bis (isopropylsulfonyl) diazomethane.

<Optional component>
The resist material of this embodiment may contain [D] acid diffusion controller, [E] solvent, crosslinking agent, etc. as optional components in addition to the above-mentioned (1) base component and (2) component. Good.

[[D] Acid diffusion controller]
[D] The acid diffusion controller controls the diffusion phenomenon in the resist film of the acid generated from (a) a radiation-sensitive acid-sensitizer generator, (c) a radiation-sensitive acid generator, etc. by irradiation. It is a substance that suppresses an undesirable chemical reaction in a non-irradiated part. [D] The content of the acid diffusion controller in the resist material may be a free compound (hereinafter referred to as “[D] acid diffusion controller”) or a form incorporated as part of the polymer. Both of these forms may be used.

[D] Examples of the acid diffusion control agent include nitrogen atom-containing compounds, photodegradable bases that are exposed to radiation and generate weak acids.

Examples of the nitrogen atom-containing compound include amine compounds, amide group-containing compounds, urea compounds, nitrogen-containing heterocyclic compounds, and the like.

Examples of the photodegradable base include triphenylsulfonium salt of carboxylic acid, and triphenylsulfonium adamantan-1-yl oxalate is preferable.

[[E] solvent]
[E] A solvent will not be specifically limited if it is a solvent which can melt | dissolve or disperse | distribute at least (1) component, (2) component, and the arbitrary component contained depending on necessity.

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

Examples of alcohol solvents include aliphatic monoalcohol solvents having 1 to 18 carbon atoms such as 4-methyl-2-pentanol and n-hexanol, and alicyclic monoalcohol solvents having 3 to 18 carbon atoms such as cyclohexanol. Examples thereof include a solvent, a polyhydric alcohol solvent having 2 to 18 carbon atoms such as 1,2-propylene glycol, and a polyhydric alcohol partial ether solvent having 3 to 19 carbon atoms such as propylene glycol monomethyl ether.

Examples of the ether solvent include diethyl ether, dipropyl ether, dibutyl ether, dipentyl ether, diisoamyl ether, dihexyl ether, diheptyl ether and other dialkyl ether solvents, tetrahydrofuran, tetrahydropyran and other cyclic ether solvents, diphenyl ether, And aromatic ring-containing ether solvents such as anisole.

Examples of ketone solvents include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-iso-butyl ketone, 2-heptanone, ethyl-n-butyl ketone, methyl-n-hexyl ketone, Chain ketone solvents such as di-iso-butyl ketone and trimethylnonanone, cyclic ketone solvents such as cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone and methylcyclohexanone, 2,4-pentanedione, acetonylacetone And acetophenone.

Examples of the amide solvent include cyclic amide solvents such as N, N′-dimethylimidazolidinone and N-methylpyrrolidone, N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N And chain amide solvents such as -methylacetamide, N, N-dimethylacetamide, and N-methylpropionamide.

Examples of ester solvents include monocarboxylic acid ester solvents such as n-butyl acetate and ethyl lactate, polyhydric alcohol carboxylate solvents such as propylene glycol acetate, and polyhydric alcohol partial ether carboxylates such as propylene glycol monomethyl ether acetate. Solvents, polyvalent carboxylic acid diester solvents such as diethyl oxalate, carbonate solvents such as dimethyl carbonate, diethyl carbonate, ethylene carbonate and propylene carbonate, and lactone solvents such as γ-butyrolactone and δ-valerolactone. .

Examples of the hydrocarbon solvent include aliphatic hydrocarbon solvents having 5 to 12 carbon atoms such as n-pentane and n-hexane, and aromatic hydrocarbon solvents having 6 to 16 carbon atoms such as toluene and xylene. It is done.

Of these, ester solvents and ketone solvents are preferred, polyhydric alcohol partial ether carboxylate solvents and cyclic ketone solvents are more preferred, and propylene glycol monomethyl ether acetate and cyclohexanone are even more preferred. The radiation-sensitive resin composition may contain one or more [E] solvents.

[Crosslinking agent]
The cross-linking agent is used to cause a cross-linking reaction between the base components by an acid catalyst reaction during the heating step after the entire surface irradiation, thereby increasing the molecular weight of the base components and insolubilizing with the developer. ) Different from the base component. Since the resist material contains a cross-linking agent, the polar part becomes nonpolar at the same time as the cross-linking and becomes insoluble in the developer, so that a negative resist material can be provided.

The crosslinking agent is a compound having two or more functional groups. Examples of the functional group include (meth) acryloyl group, hydroxymethyl group, alkoxymethyl group, epoxy group, vinyl ether group and the like.

(Content of each component)
The resist material is a radiation sensitive resin composition containing the above components. When preparing the resist material, the blending ratio of each component may be appropriately set depending on the use of the resist material, the use conditions, and the like.

(1) The lower limit of the content of the [B] precursor as the radiation-sensitive sensitizer generating agent with respect to 100 parts by mass of the component is preferably 0.1 parts by mass, more preferably 1 part by mass. Part by mass is more preferable, and 5 parts by mass is particularly preferable. As an upper limit of the said content, 50 mass parts is preferable, 30 mass parts is more preferable, 20 mass parts is further more preferable, 15 mass parts is especially preferable. [B] Sufficient sensitivity is easily obtained when the content of the precursor is not less than the above lower limit, and a rectangular resist pattern is likely to be obtained when the content is not more than the above upper limit.

(1) As a minimum of content of (c) radiation sensitive acid generator to 100 mass parts of ingredients, 1 mass part is preferred, 5 mass parts is more preferred, 10 mass parts is still more preferred, and 20 mass parts is especially preferred. preferable. As an upper limit of the said content, 50 mass parts is preferable and 40 mass parts is more preferable. (C) Sufficient sensitivity is easily obtained when the content of the radiation-sensitive acid generator is not less than the above lower limit, and a rectangular resist pattern is easily obtained when the content is not more than the above upper limit.

(1) The lower limit of the content of the [D] acid diffusion controller with respect to 100 parts by mass of the component is preferably 0.1 parts by mass, more preferably 0.5 parts by mass, and even more preferably 1 part by mass. As an upper limit of the said content, 20 mass parts is preferable, 10 mass parts is more preferable, and 5 mass parts is further more preferable. [D] When the content of the acid diffusion controller is not less than the above lower limit, the shape of the resist pattern tends to be more favorable, and on the other hand, sufficient sensitivity is easily obtained when it is not more than the above upper limit.

(1) As a minimum of content of [E] solvent to 100 mass parts of ingredients, 200 mass parts is preferred and 300 mass parts is more preferred. As an upper limit of the said content, 10,000 mass parts is preferable and 7,000 mass parts is more preferable. [E] When the content of the solvent is not less than the above lower limit, the characteristics of the resist material are hardly deteriorated. On the other hand, when the content is not more than the above upper limit, a resist film can be easily formed.

The resist material of this embodiment can be produced by mixing the above component (1), component (2), [D] acid diffusion controller, [E] solvent and the like by a known method.

<Resist pattern formation method>
The resist material is preferably used in a two-step exposure lithography process. That is, the lithography process (resist pattern forming method) according to the present embodiment includes a step of coating the resist material on a substrate (hereinafter also referred to as “coating step”) and a resist film formed by the coating step. A part of which is irradiated with radiation having a wavelength of 250 nm or less (first radiation) (hereinafter also referred to as “partial irradiation process”), and a wavelength exceeding 250 nm on the entire surface of the resist film after the partial irradiation process. A step (hereinafter also referred to as “overall irradiation step”), a step of heating the resist film after the entire surface irradiation step (hereinafter also referred to as “heating step”), And a step of developing the resist film after the heating step (hereinafter also referred to as “developing step”).

[Coating process]
In this step, the resist material is applied to the substrate. Thereby, a resist film is formed on the substrate.

The substrate may be composed of a semiconductor wafer such as a silicon substrate, a silicon dioxide substrate, a glass substrate, and an ITO substrate, or may be an insulating film layer formed on the semiconductor wafer. .

Examples of the resist material coating method include a method of applying the resist material by spin coating or the like. When the resist material is applied, the solvent in the resist material may be volatilized by heating (pre-baking) after the application. The conditions for forming the resist film are appropriately selected according to the properties of the resist material, the thickness of the resist film to be obtained, and the like. The lower limit of the average thickness of the resist film is preferably 1 nm, more preferably 10 nm, and further preferably 30 nm. The upper limit of the average thickness is preferably 5,000 nm, more preferably 1,000 nm, and even more preferably 200 nm.

Prior to forming a resist film on the substrate, a lower layer film (an antireflection film, a film for improving resist adhesion, a film for improving resist shape, etc.) may be formed on the substrate. By forming the antireflection film, it is possible to suppress the occurrence of standing waves due to radiation reflected by the substrate or the like in the partial irradiation process. By forming a film for improving the resist adhesion, the adhesion between the substrate and the resist film can be improved. By forming a film for improving the resist shape, the resist shape after development can be further improved. That is, it is possible to reduce the skirt shape or the neck shape of the resist. On the other hand, in order to prevent resist shape deterioration due to the generation of standing waves of radiation on the entire surface, it is desirable to design the thickness of the lower layer film so that reflection of radiation on the entire surface is suppressed. The lower layer film is desirably a film that does not absorb the radiation of the entire surface. If the lower layer film absorbs radiation from the entire surface, energy sensitization reaction may occur in the resist film due to energy transfer or electron transfer from the lower layer film, which may cause acid generation in the non-partially irradiated part. . For this reason, a buffer layer that does not propagate the radiation sensitization reaction may be disposed between the resist film and the lower layer film to prevent sensitization from the lower layer film that has absorbed the radiation.

A protective film may be further formed on the resist film. By forming the protective film, it is possible to suppress the deactivation of the radiation-sensitive sensitizer, the acid, and the reaction intermediate produced in the partial irradiation step, thereby improving the process stability. The protective film may be an absorption film that absorbs at least a part of the wavelength of radiation directly absorbed by the component (a) or (c) in order to prevent an acid generation reaction in a non-irradiated part in the entire surface irradiation process. Good. By using the absorbing film, it is possible to suppress the out-of-band light (OOB light), which is radiation in the ultraviolet region generated during EUV exposure, from entering the resist film, and the radiation-sensitive acid generator in the non-partially irradiated portion. It can also prevent decomposition. Further, when the absorption film is formed directly on the resist film, the film is protected with the wavelength of the second radiation in the entire irradiation process in order to suppress acid generation in the resist film due to the radiation sensitization reaction in the non-partially irradiated portion. Those that do not induce a radiosensitizing reaction from the film are preferred. An absorption film that absorbs radiation by arranging a buffer layer between the resist film and the protective film so that the radiation-sensitive sensitizer in the resist film is not sensitized by energy transfer or electron transfer from the protective film. You may prevent the sensitization from. By forming the absorption film on the resist film after the partial irradiation process and before the entire surface irradiation process, the radiation-sensitive radiation remaining on the resist film after the partial irradiation process by irradiation with the second radiation in the entire surface irradiation process. Acid can be further suppressed from being generated directly from the acid generator.

[Partial irradiation process]
In this step, a first radiation having a wavelength of 250 nm or less is irradiated to a part of the resist film formed by the coating step.

In the partial irradiation process, a light-shielding mask having a predetermined pattern is disposed on the resist film formed by the coating process. Thereafter, the resist film is irradiated with the first radiation (pattern exposure) through the mask from an exposure apparatus (radiation irradiation module) having a projection lens, an electron optical system mirror, or a reflection mirror.

The upper limit of the wavelength of the first radiation used for partial irradiation is preferably 230 nm, and more preferably 200 nm. On the other hand, the lower limit of the wavelength of the first radiation is preferably 150 nm, and more preferably 190 nm.

Examples of the first radiation include gamma rays, X-rays, alpha rays, heavy particle rays, proton rays, beta rays, ion beams, electron beams, and extreme ultraviolet rays. Among these, an electron beam, extreme ultraviolet rays, and an ion beam are preferable, and an electron beam and extreme ultraviolet rays are more preferable.

[Full irradiation process]
In this step, the entire surface of the resist film after the partial irradiation step is irradiated with the second radiation having a wavelength exceeding 250 nm.

In the entire surface irradiation step, a high sensitivity module (exposure apparatus or light source) having a projection lens (or light source) on the entire resist film surface (the entire surface including both the partial irradiation portion and the non-partial irradiation portion) after the partial irradiation step. The second radiation is irradiated (collective exposure) from a radiation irradiation module. As the entire surface irradiation, the entire surface of the wafer may be irradiated at once, a combination of local irradiations, or overlapping irradiation. A general light source can be used as the light source for the entire surface irradiation, and in addition to ultraviolet rays from mercury lamps and xenon lamps controlled to a desired wavelength by passing through a band-pass filter or a cut-off filter, LEDs Narrow-band ultraviolet light from a light source, laser diode, laser light source, or the like may be used. In the entire surface irradiation, only the sensitizer (A) generated in the partially irradiated portion in the resist material film absorbs radiation. For this reason, in the whole surface irradiation, radiation is selectively absorbed in the partial irradiation part. Therefore, during the entire surface irradiation, the acid can be continuously generated only in the partially irradiated portion, and the sensitivity can be greatly improved. On the other hand, since no acid is generated in the non-partially irradiated portion, the sensitivity can be improved while maintaining the chemical contrast in the resist film.

The lower limit of the wavelength of the second radiation is more preferably 280 nm, and further preferably 320 nm. When generating a radiation-sensitive sensitizer capable of absorbing longer wavelength radiation, the wavelength of the second radiation may be 350 nm or more. However, if the wavelength of the second radiation is too long, the efficiency of the radiation sensitization reaction will decrease, so avoid the wavelengths of radiation that can be absorbed by the base component, the radiation sensitive acid generator, and the radiation sensitive sensitizer generator. However, it is desirable to use radiation with a wavelength as short as possible that the radiation-sensitive sensitizer can absorb. From such a viewpoint, the lower limit of the wavelength of the second radiation is preferably 450 nm, and more preferably 400 nm.

[Heating process]
In the heating step, the resist film after the entire surface irradiation step is heated (hereinafter also referred to as “post-flood exposure bake (PFEB)” or “post-exposure bake (PEB)”). The heating condition can be, for example, 50 ° C. or higher and 200 ° C. or lower and 10 seconds or longer and 300 seconds or shorter in an atmosphere of an inert gas such as nitrogen or argon. By setting the heating condition within the above range, acid diffusion can be controlled, and the processing speed of the semiconductor wafer tends to be ensured. In the heating step, the acid generated in the partial irradiation step and the entire irradiation step causes (1) a polarity change reaction such as a deprotection reaction of the base component and a crosslinking reaction. Further, although the resist side wall may be wavy due to the influence of the standing wave of radiation in the resist film, the waviness can be reduced by diffusion of reactants in the heating process.

[Development process]
In the development step, the resist film after the heating step is developed. Development is performed by utilizing the fact that the solubility in the developing solution is selectively changed at a part of the irradiated portion due to the reaction in the resist film in the heating step, so that a resist pattern is formed. The developer can be divided into a positive developer and a negative developer.

An alkaline developer is preferable as the positive developer. The alkaline developer selectively dissolves the highly polar part of the resist material film after irradiation. Examples of the alkaline developer include alkaline such as potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, amines (ethanolamine, etc.), tetraalkylammonium hydroxide (TAAH), etc. Examples thereof include an alkaline aqueous solution in which at least one compound is dissolved. As the alkaline developer, an aqueous solution of TAAH is preferable. Examples of TAAH include tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide.

A 2.38% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) is widely used as a positive developer.

In alkali development, a pattern is formed by utilizing a phenomenon in which carboxylic acids and hydroxyl groups generated in a resist film after irradiation are ionized and dissolved in an alkali developer. After the development, in order to remove the developer remaining on the substrate, a water washing process called rinsing is performed.

The negative developer is preferably an organic developer. The organic developer selectively dissolves the low-polarity portion of the resist film after irradiation. The organic developer is used to improve the resolution performance and the process window by removing patterns such as holes and trenches. In this case, the dissolution contrast between the partially irradiated portion and the non-partially irradiated portion is obtained by the difference in affinity between the solvent in the resist film and the organic developer. The portion with high polarity has low solubility in an organic developer, and remains as a resist pattern. Examples of the organic developer include 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methyl acetophenone, propyl acetate, acetic acid Butyl, isobutyl acetate, amyl acetate, butenyl acetate, isoamyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl valerate, methyl pentenoate, methyl crotonic acid, ethyl crotonic acid, methyl propionate, propionate Ethyl acetate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, amyl lactate, isoamyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, Examples include methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, 2-phenylethyl acetate, and the like. .

(Substrate pattern formation)
Using the resist pattern formed by the resist pattern forming method as a mask, the base substrate is etched or ion-implanted to form a substrate pattern. The etching may be dry etching under an atmosphere such as plasma excitation, or may be wet etching immersed in a chemical solution. After the pattern is formed on the substrate by etching, the resist pattern is removed.

Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples. The measuring method of the physical property value in a present Example is shown below.

[Weight average molecular weight (Mw) and number average molecular weight (Mn)]
Mw and Mn of the polymer used GPC columns (two "G2000HXL", one "G3000HXL", one "G4000HXL" from Tosoh Corporation), a flow rate of 1.0 mL / min, elution solvent tetrahydrofuran, sample concentration 1. Measurement was performed by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard, using a differential refractometer as a detector under the analysis conditions of 0% by mass, sample injection amount 100 μL, and column temperature 40 ° C.

[ ¹³ C-NMR analysis]
The ¹³ C-NMR analysis for determining the content of the structural unit of the polymer uses a nuclear magnetic resonance apparatus (“JNM-ECX400” manufactured by JEOL Ltd.), uses CDCl ₃ as a measurement solvent, and uses tetramethylsilane ( TMS) was performed as an internal standard.

<Synthesis of [P] polymer>
The monomer used for the synthesis of [P] polymer is shown below.

The compound (M-1) is the structural unit (I), the compound (M-2) is the structural unit (II), (M-3) is the deacetylated structural unit (III), and the compound ( M-4) gives structural units (IV), respectively. In the following polymer synthesis examples, unless otherwise specified, parts by mass means a value when the total mass of monomers used is 100 parts by mass, and mol% is the amount of monomers used. It means the value when the total number of moles is 100 mol%.

[Synthesis Example 1] (Synthesis of polymer (P1))
In the reaction vessel, the compound (M-1) and the compound (M-2) as monomers were dissolved in 300 parts by mass of 2-butanone so that the molar ratio was 50/50. Here, 3 parts by mass of AIBN as a radical polymerization initiator was added and purged with nitrogen for 30 minutes. The inside of the reaction vessel was brought to 78 ° C., and the polymerization reaction was carried out for 6 hours while stirring. After completion of the polymerization reaction, the polymerization solution was cooled with water and cooled to 30 ° C. or lower. The cooled polymerization solution was put into 2,000 parts by mass of methanol, and the precipitated white powder was filtered off. The filtered white powder was washed twice with methanol, filtered, and dried at 50 ° C. for 17 hours to obtain a white powdery polymer (P1) with a good yield. Mw of the polymer (P1) was 7,000, and Mw / Mn was 2.10. As a result of ¹³ C-NMR analysis, the content of each structural unit derived from (M-1) and (M-2) was 52 mol% and 48 mol%, respectively.

[Synthesis Example 2] (Synthesis of Polymer (P2))
In a reaction vessel, the compound (M-1) and the compound (M-3) as monomers were dissolved in 150 parts by mass of propylene glycol monomethyl ether so that the molar ratio was 44/56. A monomer solution was prepared by adding 3 parts by mass of AIBN as a radical polymerization initiator and 1 part by mass of t-dodecyl mercaptan as a chain transfer agent. This monomer solution was polymerized for 16 hours under a nitrogen atmosphere while maintaining the reaction temperature at 70 ° C. After completion of the polymerization reaction, the polymerization solution was dropped into 1,000 parts by mass of n-hexane to solidify and purify the polymer. To the above polymer, 150 parts by mass of propylene glycol monomethyl ether was added. Further, 150 parts by mass of methanol, 37 parts by mass of triethylamine and 7 parts by mass of water were added, and the hydrolysis reaction was performed for 8 hours while refluxing at the boiling point. After completion of the reaction, the solvent and triethylamine were distilled off under reduced pressure, and the resulting polymer was dissolved in 150 parts by mass of acetone. This was dropped into 2,000 parts by mass of water and solidified, and the produced white powder was filtered off. It was dried at 50 ° C. for 17 hours to obtain a white powdery polymer (P2) with a good yield. Mw of the polymer (P2) was 6,000, and Mw / Mn was 1.90. As a result of ¹³ C-NMR analysis, the content of each of the structural unit derived from (M-1) and the structural unit derived from p-hydroxystyrene obtained by deacetylation of (M-3) was 50 mol each. % And 50 mol%.

[Synthesis Example 3] (Synthesis of polymer (P3))
In a reaction vessel, compound (M-1), compound (M-3) and compound (M-4) as monomers were mixed with 200 parts by mass of propylene so that the molar ratio was 40/40/20. Dissolved in glycol monomethyl ether. A monomer solution was prepared by adding 4 parts by mass of AIBN as a radical polymerization initiator. In another reaction vessel, 100 parts by mass of propylene glycol monomethyl ether was charged, the reaction temperature was maintained at 80 ° C., and the monomer solution prepared above was dropped therein over 3 hours, and polymerization was further performed for 3 hours. After completion of the polymerization, the polymerization reaction liquid was cooled with water and cooled to 30 ° C. or lower. The polymer solution was dropped into 2,000 parts by mass of n-hexane to solidify and purify the polymer. The solid content after filtration was washed twice with 400 parts by mass of hexane, further filtered, and dried at 50 ° C. for 17 hours. To the above polymer, 100 parts by mass of propylene glycol monomethyl ether was added. 17.5 parts by mass of triethylamine and 2.8 parts by mass of water were added, and the mixture was heated to 80 ° C. and subjected to a hydrolysis reaction for 6 hours. After completion of the reaction and after completion of hydrolysis, the reaction solution was cooled with water and cooled to 30 ° C. or lower. The obtained polymer was added to 2,000 parts by mass of hexane, and the precipitated solid content was separated by filtration. The solid content separated by filtration was washed twice with 40 parts by mass of hexane, further filtered, and dried at 50 ° C. for 17 hours to obtain a polymer (P3) in good yield. Mw of the polymer (P3) was 7,500, and Mw / Mn was 1.52. As a result of ¹³ C-NMR analysis, structural units derived from (M-1), p-hydroxystyrene structural units obtained by deacetylation of (M-3), and structural units derived from (M-4) Each content rate was 40 mol%, 40 mol%, and 20 mol%, respectively.

Table 1 shows the Mw, Mw / Mn, and the content ratio of each structural unit of the obtained polymers (P1) to (P3).

The content ratio of the structural unit (M-3) in Table 1 is the content as a structural unit derived from p-hydroxystyrene obtained by deacetylating the structural unit derived from (M-3). Indicates the percentage.

<Synthesis of [B] precursor>
[Synthesis Example 4]
To the reaction vessel, 50 mmol of 3,4-dihydroxybenzophenone, 50 mmol of 2,2-dimethoxypropane, 0.05 g of p-toluenesulfonic acid monohydrate and 400 g of toluene were added. After dehydrating and refluxing with Dean-Stark for 3 hours, the reaction solution was cooled. After cooling overnight, the precipitated raw material 3,4-dihydroxybenzophenone was removed by filtration, and the filtrate was neutralized by adding 0.2 g of a sodium methoxide methanol solution (28% by mass). The neutralized solution was concentrated under reduced pressure and then purified by alumina column chromatography to obtain a compound represented by the following formula (B1).

[Synthesis Example 5]
To the reaction vessel, 79.7 mmol of 3,4-dihydroxybenzophenone, 2,000 mmol of trimethyl orthoformate, 0.1 g of p-toluenesulfonic acid monohydrate and 40 g of toluene were added. After dehydrating and refluxing with Dean-Stark for 12 hours, the reaction solution was cooled. After cooling overnight, 0.2 g of sodium methoxide methanol solution (28% by mass) was added to the filtrate for neutralization. The neutralized solution was concentrated under reduced pressure, and then purified by alumina column chromatography to obtain a compound represented by the following formula (B2).

[Synthesis Example 6]
To a reaction vessel equipped with a Dean-Stark apparatus, 231 mmol of 4,4′-dihydroxybenzophenone, 2,160 mmol of ethylene glycol, 913 mmol of trimethyl orthoformate and 0.5 g of p-toluenesulfonic acid monohydrate were added. After heating and stirring at 80 ° C. for 2 hours, the heating temperature was gradually raised to 120 ° C., and heating was continued while removing the distillate until distillation of methanol, methyl formate and trimethyl orthoformate was completed. The reaction solution was cooled to room temperature, diluted with ethyl acetate, the organic phase was washed with a 5% by mass aqueous sodium bicarbonate solution, and the organic phase was concentrated under reduced pressure. The resulting concentrate is crystallized by adding 80 mL of methylene chloride, and the resulting crystals are filtered off and washed with methylene chloride cooled to 5 ° C., and expressed by the following formula (B3). A compound was obtained.

<Screening evaluation of sensitizer>
[Preparation of resist material for sensitizer screening]
A resist material for screening a sensitizer was prepared. Components other than the [P] polymer used for the preparation are shown below.

((A) sensitizer)
A1 and A2 and CA1 to CA4: compounds represented by the following formulas (A1) and (A2) and (CA1) to (CA4)

([C] radiation sensitive acid generator)
C1: Compound represented by the following formula (C1)

([D] acid diffusion controller)
D1: Compound represented by the following formula (D1)

([E] solvent)
E1: Propylene glycol monomethyl ether acetate E2: Ethyl lactate

[Preparation Example 1]
[P] 100 parts by mass of (P3) as a polymer, (A) 10 parts by mass of (A1) as a sensitizer, [C] 20 parts by mass of (C1) as a radiation-sensitive acid generator, [D] 0.3 parts by mass of (D1) as an acid diffusion controller and 4,300 parts by mass of (E1) as a solvent [E] and 1,900 parts by mass of (E2) were mixed. The obtained mixed solution was filtered through a membrane filter having a pore size of 0.20 μm to prepare a resist material (S-1) for sensitizer screening.

[Preparation Examples 2 to 7]
Resist materials (S-2) and (CS-1) to (CS-5) were prepared in the same manner as in Preparation Example 1, except that the type and amount of (A) sensitizer shown in Table 2 were changed. did. “-” In Table 2 indicates that the corresponding component was not used.

[Sensitizer screening evaluation]
In the “Clean Track ACT-8” of Tokyo Electron, the resist material prepared above was spin-coated on a silicon wafer, and then PB was performed at 130 ° C. for 60 seconds to form a resist film having an average thickness of 50 nm. . Next, this resist film was irradiated with i-line at an area of 0.5 cm square at 1,000 mJ / cm ² using an i-line stepper (“NSR2205i12D” manufactured by Nikon Corporation). After i-ray irradiation, PEB was performed in the clean track ACT-8 at 110 ° C. for 60 seconds, and then 2.38 mass% tetramethylammonium hydroxide (TMAH) in the clean track ACT-8. Development was performed by the paddle method at 23 ° C. for 1 minute using an aqueous solution. After development, a positive resist pattern was formed by washing with pure water and drying. After this treatment, the film thickness in the i-ray irradiated part was confirmed, and the residual film was 0, that is, the resolution was A (good), and the resolution was not B (defect). . The evaluation results are shown in Table 3 below. In this test, for those that were A (good), the sensitizer was excited by absorbing i-rays, and energy or electron transfer from the exciter to the radiation-sensitive acid generator efficiently occurred, It is presumed that acid was generated from the radiation-sensitive acid generator, and then the deprotection reaction of the polymer proceeded.

<Preparation of chemically amplified resist material>
A chemically amplified resist material was prepared using the [B] precursor that provides (A) a sensitizer that was effective in screening evaluation of the sensitizer. In addition, the resist material of the comparative example includes benzophenone dimethyl ketal (Tokyo Chemical Industry Co., Ltd.), which is a precursor of the sensitizer (CA4) used in the resist material (CS-4) (“CB1” in Table 3 below). Was used.

[Example 1]
[P] 100 parts by mass of (P3) as a polymer, 10 parts by mass of (B1) as a [B] precursor, [C] 20 parts by mass of (C1) as a radiation sensitive acid generator, [D] acid 2.0 parts by mass of (D1) as a diffusion control agent and 4,300 parts by mass of (E1) as a solvent [E] and 1,900 parts by mass of (E2) were mixed. The obtained mixed solution was filtered through a membrane filter having a pore size of 0.20 μm to prepare a chemically amplified resist material (R-1).

[Examples 2 and 3 and Comparative Examples 1 and 2]
Chemically amplified resist materials (R-2) and (R-3) and (CR-1) were the same as in Example 1 except that the types and amounts of the [B] precursors shown in Table 4 were changed. And (CR-2) were prepared. “-” In Table 4 indicates that the corresponding component was not used.

<Evaluation>
Within the “Clean Track ACT-8” of Tokyo Electron, the chemically amplified resist material prepared above was spin-coated on a silicon wafer, and then PB was performed at 130 ° C. for 60 seconds to obtain a resist film having an average thickness of 50 nm. Formed. Patterning was performed by irradiating the resist film with an electron beam using a simple electron beam drawing apparatus (“HL800D” manufactured by Hitachi, Ltd., output 50 KeV, current density 5.0 A / cm ² ). The patterning method, an operation of irradiating a predetermined exposure amount 0.5cm square area, until ^{1μC / cm 2 ~ 50μC / cm} 2, was carried out a total of 50 points at 1 [mu] m / cm ² increments. After the electron beam irradiation, the following operations (1) and (2) were subsequently performed for evaluation.

(Operation (1): No full irradiation)
After the electron beam irradiation, PEB was performed in the clean track ACT-8 at 110 ° C. for 60 seconds, and then in the clean track ACT-8 using a 2.38 mass% TMAH aqueous solution at 23 ° C. Developed by paddle method for 1 minute. After development, a positive resist pattern was formed by washing with pure water and drying.

(Operation (2): With full surface irradiation)
After the electron beam irradiation, the entire surface of the resist film was exposed at 2,000 mJ / cm ² using an LED (wavelength 365 nm) manufactured by Hamamatsu Photonics. Next, PEB was performed in the clean track ACT-8 at 110 ° C. for 60 seconds. Thereafter, development, washing and drying were carried out in the same manner as in the above operation (1) to form a positive resist pattern.

With respect to the positive resist pattern thus formed, the electron beam exposure amount at which the film thickness when it is performed in operation (1) is 0 is E1 (μC / cm ² ), and the film thickness when it is performed in operation (2). When E2 (μC / cm ² ) is 0 when the electron beam exposure dose is 0, A (sensitization effect) is obtained when (E2 / E1) <0.8, and (E2 / E1) ≧ 0. The case of 8 was evaluated as B (small sensitizing effect or no sensitizing effect). The evaluation results are shown in Table 5 below.

From the results in Table 5, generation of radiation-sensitive acid by electron beam exposure only when a precursor of a sensitizer recognized as having a sensitizing effect on irradiation at 365 nm by screening evaluation of i-line exposure was used. The precursor is converted into a sensitizer by the generation of acid from the agent, and the subsequent irradiation with 365 nm light further promotes the decomposition of the radiation-sensitive acid generator due to the sensitization effect. As a result, a small electron beam It is presumed that deprotection and resolution of the polymer can be realized at the exposure amount.

According to the present invention, in pattern formation technology using radiation having a wavelength of 250 nm or less, such as EUV light, electron beam, ion beam, KrF excimer laser, ArF excimer laser, etc., both high sensitivity and excellent lithography characteristics are enhanced. There is provided a chemically amplified resist material that can achieve the standard. Moreover, according to this invention, the pattern formation method using the said resist material is provided.

Claims (9)

1. Irradiating a part of a resist film formed using the photosensitive resin composition with a first radiation having a wavelength of 250 nm or less;
   Irradiating the entire surface of the resist film after the partial irradiation step with a second radiation having a wavelength of more than 250 nm;
   Heating the resist film after the entire surface irradiation step;
   In a lithography process comprising a step of developing the resist film after the heating step with a developer, a chemically amplified resist material used as the photosensitive resin composition,
   (1) a base component that becomes soluble or insoluble in the developer by the action of an acid;
   (2) a component that generates a radiation-sensitive sensitizer and an acid upon irradiation,
   The component (2) contains the following components (a) and (b), the following components (b) and (c), or the following components (a) to (c):
   A chemically amplified resist material comprising a precursor in which the component (b) is decomposed by the action of an acid to yield a compound represented by the following formula (A).
   (A) In the non-irradiation part that generates the acid and the radiation-sensitive sensitizer that absorbs the second radiation by the irradiation of the first radiation and is not irradiated with the first radiation in the partial irradiation step, Radiation-sensitive acid-sensitizer generator that does not substantially generate the acid and radiation-sensitive sensitizer upon irradiation with the second radiation (b) Radiation-sensitive that absorbs the second radiation upon irradiation with the first radiation In the non-irradiated part that generates the photosensitizer and is not irradiated with the first radiation in the partial irradiation step, the radiation-sensitive sensitizer is not substantially generated by the irradiation of the second radiation. Body generator (c) In the non-irradiated part where the first radiation is not irradiated with the first radiation and the acid is substantially generated by the second radiation. Does not cause radiation sensitive acid generator
   

   

   (In the formula (A), R ^a to R ^d are each independently a hydrogen atom, an amino group, a sulfanyl group, a halogen atom, or a monovalent organic group having 1 to 20 carbon atoms, and R ¹ to R ⁶ Each independently represents a hydrogen atom, a hydroxy group, an amino group, a sulfanyl group, a halogen atom or a monovalent organic group having 1 to 20 carbon atoms, or R ^a to R ^d and R ¹ to R ⁶ . 2 or more of them are part of a ring structure having 4 to 20 ring members constituted with a carbon chain to which they are bonded to each other, provided that at least one of R ¹ to R ⁶ is a hydroxy group .)
2. (1) a base component that is soluble or insoluble in a developer by the action of an acid;
   (2) a component that generates a radiation-sensitive sensitizer and an acid upon irradiation,
   The above component (2) contains the following components (a) and (b), the following components (b) and (c), or the following components (a) to (c):
   A chemically amplified resist material comprising a precursor in which the component (b) is decomposed by the action of an acid to yield a compound represented by the following formula (A).
   (A) Irradiation of the first radiation having a wavelength of 250 nm or less generates an acid and a radiation-sensitive sensitizer that absorbs the second radiation having a wavelength exceeding 250 nm, and the first radiation is not irradiated. Radiation-sensitive acid-sensitizer generating agent that does not substantially generate the acid and radiation-sensitive sensitizer when irradiated only with the second radiation (b) The second radiation is irradiated by the irradiation of the first radiation. A radiation-sensitive sensitizer that generates a radiation-sensitive sensitizer to be absorbed and that does not substantially generate the radiation-sensitive sensitizer when only the second radiation is irradiated without irradiation with the first radiation. (C) A radiation-sensitive acid generator that generates an acid upon irradiation with the first radiation and does not substantially generate the acid when only the second radiation is irradiated without irradiation with the first radiation.
   

   

   (In the formula (A), R ^a to R ^d are each independently a hydrogen atom, an amino group, a sulfanyl group, a halogen atom, or a monovalent organic group having 1 to 20 carbon atoms, and R ¹ to R ⁶ Each independently represents a hydrogen atom, a hydroxy group, an amino group, a sulfanyl group, a halogen atom or a monovalent organic group having 1 to 20 carbon atoms, or R ^a to R ^d and R ¹ to R ⁶ . 2 or more of them are part of a ring structure having 4 to 20 ring members constituted with a carbon chain to which they are bonded to each other, provided that at least one of R ¹ to R ⁶ is a hydroxy group .)
3. 3. The chemically amplified resist material according to claim 1, wherein at least two of R ¹ to R ⁶ in the formula (A) are hydroxy groups.
4. The chemically amplified resist material according to claim 1, wherein R ² in the formula (A) is a hydroxy group.
5. The chemically amplified resist material according to claim 4, wherein the precursor is represented by the following formulas (B-1) to (B-4).
   

   

   (In the formulas (B-1) to (B-4), R ^a to R ^d each independently represents a hydrogen atom, an amino group, a sulfanyl group, a halogen atom, or a monovalent organic group having 1 to 20 carbon atoms. R ¹ to R ⁶ are each independently a hydrogen atom, a hydroxy group, an amino group, a sulfanyl group, a halogen atom, or a monovalent organic group having 1 to 20 carbon atoms, or R ^a to R 6 ^d and two or more of R ¹ to R ⁶ are part of a ring structure having 4 to 20 ring members formed together with the carbon chain to which they are bonded to each other, and R ^A and R ^B are each independently A part of a ring structure having 4 to 20 ring members, which is a monovalent organic group having 1 to 20 carbon atoms, or O—C—O in which these groups are combined with each other. R ^C and R ^D are each independently 1 to 20 carbon atoms. Or a part of a ring structure of 3 to 20 ring members composed of these groups together with the carbon atoms to which they are attached.)
6. The chemically amplified resist material according to any one of claims 1 to 5, wherein the component (1) is a polymer whose solubility in a developer is changed by the action of an acid.
7. The chemically amplified resist material according to any one of claims 1 to 6, comprising (c) a radiation-sensitive acid generator as the component (2).
8. The chemically amplified resist material according to any one of claims 1 to 6, comprising a polymer having an acid-generating group as the component (2).
9. Applying the chemically amplified resist material according to any one of claims 1 to 8 on a substrate;
   Irradiating a part of the resist film formed by the coating process with radiation having a wavelength of 250 nm or less;
   Irradiating the entire surface of the resist film after the partial irradiation step with radiation having a wavelength of more than 250 nm;
   Heating the resist film after the entire surface irradiation step;
   And a step of developing the resist film after the heating step.