TW201346442A - Photoresist composition, method for forming resist pattern, polymer and compound - Google Patents

Abstract

The present invention is a photoresist composition which contains [A] a polymer that has a structural unit represented by formula (1), and [B] an acid generator. In formula (1), R1 represents a divalent polycyclic alicyclic hydrocarbon group having 4-20 carbon atoms; R2 represents a monovalent monocyclic or polycyclic alicyclic hydrocarbon group having 3-20 carbon atoms; and R3 represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. It is preferable that the polymer [A] additionally has a structural unit that contains at least one structure selected from the group consisting of a lactone structure, a cyclic carbonate structure and a sultone structure. It is also preferable that the polymer [A] additionally has a structural unit represented by formula (2).

Description

Photoresist composition, method for forming photoresist pattern, polymer and compound

The present invention relates to a photoresist composition, a method for forming a photoresist pattern, a polymer, and a compound.

The chemically-enhanced photoresist composition for micro-machining is produced by exposure to an ultraviolet light such as an ArF excimer laser light, an electromagnetic wave such as X-ray, or a charged particle beam such as an electron beam. The acid, by the chemical reaction of the acid as a catalyst, causes the exposed portion and the unexposed portion to have a dissolution rate with respect to the developing liquid to form a photoresist pattern.

This photoresist composition is required to improve the lithography performance such as sensitivity and resolution as the processing technology is refined. In addition to the above-mentioned requirements, it is possible to improve the resolution of the acid-dissociable group of the polymer contained in the various photoresist compositions, for example, to review the ring structure having a specific complex number (see Japanese Special Open 2011). -43794 bulletin).

However, the miniaturization of the resist pattern has progressed to a level of a half pitch of 40 nm or less, and the photoresist composition is required to have excellent resolution and the like, and it is necessary to form a high-precision pattern with high yield. It is required to have excellent performance such as LWR (Line Width Roughness), EL (Exposure Latitude, exposure margin). But the above past The photoresist composition still does not meet these properties.

[Advanced technical literature] [Patent Literature]

[Patent Document 1] Japanese Laid-Open Patent Publication No. 2011-43794

[Summary of the Invention]

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a photoresist composition excellent in LWR performance and EL performance.

In order to solve the above problems, the invention has a polymer having a structural unit represented by the following formula (1) (hereinafter also referred to as "structural unit (I)") (hereinafter also referred to as "[A] polymer"). And a photoresist composition of an acid generator (hereinafter also referred to as "[B] acid generator").

(In the formula (1), R ¹ is a divalent polycyclic alicyclic hydrocarbon group having 4 to 20 carbon atoms; and R ² is a monovalent monocyclic or polycyclic alicyclic hydrocarbon group having 3 to 20 carbon atoms. R ³ Is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group).

The photoresist composition of the present invention contains the above specific The structural unit [A] polymer and [B] acid generator are excellent in LWR performance and EL performance. Although the reason why the photoresist composition exhibits the above-described effects by the above configuration is not clear, it can be estimated as follows. In other words, the acid dissociable group of the [A] polymer is a structure in which a polycyclic alicyclic hydrocarbon group is bonded to a monocyclic or polycyclic alicyclic hydrocarbon group, a carbon number is relatively large, and the acid dissociable group bond is bonded. An ester group bonded directly to the backbone of the [A] polymer. As a result, the rigidity of the [A] polymer was moderately increased, and the solubility of the unexposed portion to the developing solution was lowered. Further, since the acid dissociable group has the above specific structure, the dissociation property is high and the solubility of the exposed portion is increased. Therefore, the dissolution of the exposed portion and the unexposed portion is improved, and as a result, the LWR performance and the EL performance of the photoresist composition are estimated to be improved.

R ² in the above formula (1) is preferably a monocyclic alicyclic hydrocarbon group, more preferably a saturated hydrocarbon group having 5 to 8 carbon atoms.

Due to moderate bulkiness (Bulky) R ² has, the thus appropriately adjust the rigidity of [A] to polymer, and, more improved dissociable group-of dissociable above acid, more increase the dissolution contrast, can be a higher level The state has both the LWR performance and the EL performance of the photoresist composition.

R ¹ in the above formula (1) is preferably a bridged saturated hydrocarbon group having 7 to 12 carbon atoms, more preferably a tricyclo[3.3.1.1 ^3,7 ]nonane-2,2-diyl group.

The higher bulkiness of R ¹ can improve the rigidity of [A] polymer and improve the dissolution contrast, so that the LWR performance and EL performance of the photoresist composition can be combined at a higher level.

[A] the polymer preferably further contains a lactone structure selected from the group consisting of A structural unit of at least one structure in which a carbonate structure and a sultone structure are grouped (hereinafter also referred to as "structural unit (III)"). [A] The polymer can be appropriately adjusted in solubility due to the specific structural unit described above. Further, the adhesion of the photoresist pattern formed by the photoresist composition to the substrate or the like can be improved. These results can improve the LWR performance and EL performance of the photoresist composition.

The [A] polymer is more preferably a fluorine atom. [A] polymer again The fluorine atom is contained and can be suitably used as a water-repellent additive. As a result, the photoresist composition can be excellent in image defect suppressing property.

The [A] polymer preferably further has a knot represented by the following formula (2) Construction unit (hereinafter also referred to as "structural unit (II)").

(In the formula (2), R ⁴ is a monovalent chain hydrocarbon group having 1 to 10 carbon atoms; and R ⁵ and R ⁶ are each independently a monovalent chain hydrocarbon group having 1 to 10 carbon atoms or 1 to 3 carbon atoms; a valence alicyclic hydrocarbon group, or R ⁵ and R ^{6 are} bonded to each other and to a carbon atom to which they are bonded, together form a divalent cyclic group having 3 to 20 carbon atoms. R ⁷ is a hydrogen atom, a fluorine atom or a methyl group. Or trifluoromethyl).

[A] polymer has the above specific structural unit and can be adjusted Straightness can adjust its solubility more moderately. As a result, the LWR performance and the EL performance of the photoresist composition can be further improved.

The content ratio of the structural unit represented by the above formula (1) is relative The total structural unit constituting the [A] polymer is preferably 5 mol% or more and 50 mol% or less. When the content ratio of the above structural unit is within the above specific range, the LWR performance and the EL performance of the photoresist composition can be further improved.

The method for forming a photoresist pattern of the present invention comprises the steps of: forming a photoresist film by a photoresist composition, exposing the photoresist film, and exposing the exposed photoresist film; Like the steps.

According to the method for forming the photoresist pattern, since the photoresist composition of the present invention described above is provided, a wide EL can be secured, and a photoresist pattern excellent in LWR can be formed.

The polymer of the present invention has a structural unit represented by the following formula (1).

(In the formula (1), R ¹ is a divalent polycyclic alicyclic hydrocarbon group having 4 to 20 carbon atoms; and R ² is a monovalent monocyclic or polycyclic alicyclic hydrocarbon group having 3 to 20 carbon atoms. R ³ Is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group).

R ² in the above formula (1) is preferably a monocyclic alicyclic hydrocarbon group, more preferably a saturated hydrocarbon group having 5 to 8 carbon atoms.

R ¹ in the above formula (1) is preferably a bridged saturated hydrocarbon group having 7 to 12 carbon atoms, more preferably a tricyclo[3.3.1.1 ^3,7 ]nonane-2,2-diyl group.

The polymer is preferably used as the polymer component of the above-described photoresist composition of the present invention because it has the above specific structural unit.

The compound of the present invention is represented by the following formula (i).

(In the formula (i), R ¹ is a divalent polycyclic alicyclic hydrocarbon group having 4 to 20 carbon atoms. R ² is a monovalent monocyclic or polycyclic alicyclic hydrocarbon group having 3 to 20 carbon atoms. R ³ Is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group).

R ² in the above formula (i) is preferably a monocyclic alicyclic hydrocarbon group, more preferably a saturated hydrocarbon group having 5 to 8 carbon atoms.

R ¹ in the above formula (i) is preferably a bridged saturated hydrocarbon group having 7 to 12 carbon atoms, more preferably a tricyclo[3.3.1.1 ^3,7 ]nonane-2,2-diyl group.

This compound is suitable for the specific structure described above. It is used as a monomer which provides the structural unit (I) of the above polymer.

As described above, according to the method for forming a photoresist composition and a photoresist pattern of the present invention, a wide EL can be secured, and a photoresist pattern excellent in LWR can be formed. Further, when the photoresist composition containing the [A] polymer as a water-repellent additive is used, occurrence of development defects in the photoresist pattern can be suppressed. The polymer of the present invention is suitably used as a polymer component of the photoresist composition. The compound of the present invention is suitably used as a raw material monomer of the polymer. Therefore, the photoresist composition, the method for forming a photoresist pattern, the polymer and the compound of the present invention are suitable for use in a semiconductor manufacturing process which requires high-precision pattern formation at a high yield.

[Formation of the Invention]

<Photoresist composition>

The photoresist composition contains a [A] polymer and a [B] acid generator. The photoresist composition may further contain [C] other polymer, [D] acid diffusion control body, and [E] solvent, which are preferably contained in the structural unit (I), without impairing the effects of the present invention. Within the scope, it may contain other optional components. Each component will be described below.

The photoresist composition may contain only a base polymer as a polymer component, and may contain a water-repellent additive in addition to the base polymer. The "base polymer" refers to a polymer which is a main component of the photoresist film formed of the photoresist composition, and preferably contains 50% by mass or more of the polymer based on the total polymer constituting the photoresist film. Moreover, "water-repellent additive" means a product which is contained in a photoresist composition and which has a surface which is biased to form a surface of the photoresist film. To the polymer. A polymer having a higher hydrophobicity than a polymer which becomes a base polymer has a tendency to be biased to the surface layer of the photoresist film, and has a function as a water-repellent additive. The photoresist composition contains a water-repellent additive, and can suppress dissolution of an acid generator such as a photoresist film, and the surface of the photoresist film formed exhibits a high dynamic contact angle, so that the surface of the photoresist film can exhibit excellent water removal characteristics. . Therefore, in the liquid immersion exposure process, it is not necessary to separately provide an upper film for blocking the surface of the photoresist film and the liquid immersion medium, and the scanning can be performed at a high speed, and the occurrence of water mark defects and the like can be suppressed.

In the photoresist composition, in order to produce a good function as a water-repellent additive, the water-repellent additive preferably has a fluorine atom, and the water-repellent additive has a fluorine atom content higher than that of the base polymer. When the fluorine atom content of the water-repellent additive is larger than that of the base polymer, the water-repellent additive tends to be more polarized on the surface layer of the photoresist film, so that the high water-removing property of the surface of the photoresist film constitutes a water-repellent additive. The special properties caused by the hydrophobicity of the polymer are more effective. The fluorine atom content (% by mass) can be obtained from the structure of the polymer as determined by ¹³ C-NMR.

The aspect of the photoresist composition is, for example, a polymer component Containing [A] polymer as (1) base polymer, [A] polymer as (2) base polymer, and [A] polymer as water-repellent additive, respectively, as (3) base polymer [ A] polymer and other polymer [C] as water-repellent additive, [C] other polymer as (4) base polymer, and [A] polymer as a water-repellent additive. When the photoresist composition of the above (2) to (4) contains both the base polymer and the water-repellent additive, even [A] When the polymer is used only for the above (3) and (4) of one of the base polymer or the water-repellent additive, the effect of the present invention can be sufficiently exerted, but the [A] polymer is used for the base polymer and the water-repellent additive. In the case of the above two (2), the effects of the present invention can be further enhanced. The constituent components of the photoresist composition will be described in order below.

<[A]polymer>

[A] The polymer is a polymer having a structural unit (I). This photoresist composition is excellent in EL performance and LWR performance because the [A] polymer has a structural unit (I). Further, since the photoresist composition having the water-repellent additive [A] polymer has a structural unit (I), it is excellent in development defect suppressing property. Although the photoresist composition has the above-described configuration, the reason why the above-described effects can be exhibited is not clear, but it is presumed to be as follows. In other words, the acid-dissociable group of the [A] polymer is a polycyclic alicyclic hydrocarbon group having a monocyclic or polycyclic alicyclic hydrocarbon group bonded structure, and the carbon number is relatively large, and the acid dissociable group is a direct bond. An ester-based bond to the backbone of the [A] polymer. As a result, the rigidity of the [A] polymer was moderately increased, and the solubility of the unexposed portion to the developing solution was lowered. Further, since the acid dissociable group has the above specific structure, the dissociation property is increased, and the solubility of the exposed portion is increased. Thereby, the dissolution of the exposed portion and the unexposed portion is improved, and as a result, the LWR performance and the EL performance of the photoresist composition are improved, and when the [A] polymer is used as the water-repellent additive, the development defect suppressing property can be improved.

[A] The polymer preferably has an upper layer in addition to the structural unit (I) The structural unit (II) represented by the formula (2), a structural unit containing at least one structure selected from the group consisting of a lactone structure, a cyclic carbonate structure, and a sultone structure (III) may also have a structural unit (IV) containing a polar group. Further, in particular, when the [A] polymer is used as a water-repellent additive, it is preferable to further contain a fluorine atom, and more preferably a structural unit (F-I) having a fluorine atom to be described later. The [A] polymer may also contain other structural units than these structural units. The [A] polymer may have one or two or more such structural units. Each structural unit will be described below.

[Structural Unit (I)]

The structural unit (I) is a structural unit represented by the above formula (1).

In the above formula (1), R ¹ is a divalent polycyclic alicyclic hydrocarbon group having 4 to 20 carbon atoms. R ² is a monocyclic or polycyclic alicyclic hydrocarbon group having a monovalent or polycyclic number of 3 to 20 carbon atoms. R ³ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

The above-mentioned R ¹ represents a divalent polycyclic alicyclic hydrocarbon group having 4 to 20 carbon atoms, as long as it is a group in which two hydrogen atoms are removed from the same carbon atom constituting the carbon ring of the above-mentioned carbon number polycyclic alicyclic hydrocarbon. In the case of a group, there is no particular limitation, for example, bicyclo[1.1.0]butane-2,2-diyl, bicyclo[2.1.0]pentane-2,2-diyl, bicyclo[2.2.0]hexane Non-bridged saturated hydrocarbon group of -2,2-diyl, etc.; bicyclo[2.2.1]heptane-2,2-diyl (norbornane-2,2-diyl), bicyclo[2.2.2]octane a saturated hydrocarbon group such as a bridged saturated hydrocarbon group such as a 2,2-diyl group, a tricyclo[3.3.1.1 ^3,7 ]nonane-2,2-diyl (adamantane-2,2-diyl group); 2.1.0] non-bridged unsaturated hydrocarbon group of pentene-2,2-diyl, bicyclo[2.2.0]hexene-2,2-diyl, etc; bicyclo[2.2.1]heptene-2,2- Dibasic, bicyclo[2.2.1]heptadiene-2,2-diyl, bicyclo[2.2.2]octene-2,2-diyl, bicyclo[2.2.2]octadiene-2,2- An unsaturated hydrocarbon group such as a dibasic or bicyclo[2.2.2]octetylene-2,2-diyl group or the like which bridges an unsaturated hydrocarbon group. The bridged hydrocarbon group means an alicyclic hydrocarbon group having a structure in which carbon atoms constituting an alicyclic ring are crosslinked by one or more carbon atoms, and the non-bridged hydrocarbon group means a structure in which a carbon atom constituting an alicyclic ring is bonded by a single bond. An alicyclic hydrocarbon group.

Among these, a saturated hydrocarbon group is preferred, a saturated hydrocarbon group is more preferably bridged, a bridged saturated hydrocarbon group having a carbon number of 7 to 12 is more preferred, and a saturated hydrocarbon group of 3 or more rings is particularly preferred, and a tricyclic ring is particularly preferred [3.3.1.1 ^3,7 ]decane-2,2-diyl. R ^{1 is} formed to be more bulky (Bulky) to improve the rigidity of the [A] polymer and to improve the dissolution contrast, and to achieve the LWR properties and EL properties of the photoresist composition at a higher level.

The above R ² represents a monovalent monocyclic or polycyclic alicyclic hydrocarbon group having 3 to 20 carbon atoms, for example, a monocyclic alicyclic hydrocarbon group such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, or a ring. a saturated hydrocarbon group such as heptyl, cyclooctyl, cyclodecyl or cyclododecyl; cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, cycloheptenyl, cyclooctenyl, An unsaturated hydrocarbon group such as cyclodecenyl; a polycyclic alicyclic hydrocarbon group such as bicyclo[1.1.0]butyl, bicyclo[2.1.0]pentyl, bicyclo[2.2.0]hexyl, bicyclo[2.2.1 a saturated hydrocarbon group such as heptyl (norbornyl), bicyclo [2.2.2] octyl, tricyclo[3.3.1.1 ^3,7 ] fluorenyl (adamantyl); bicyclo[2.1.0]butenyl, Bicyclo [2.2.0] hexenyl, bicyclo [2.2.1] heptenyl (norpokenyl), bicyclo [2.2.1] heptadienyl, bicyclo [2.2.2] octenyl, bicyclo [2.2 .2] an unsaturated hydrocarbon group such as an octadienyl group or a bicyclo[2.2.2]octenyl group.

Among these, a saturated hydrocarbon group is preferred. Further, a monocyclic alicyclic hydrocarbon group is preferred, and a monocyclic saturated hydrocarbon group is more preferred, and a monocyclic saturated hydrocarbon group having 5 to 8 carbon atoms is more preferred, and a cyclopentyl group or a cyclohexyl group is particularly preferred. R ² has a moderate bulkiness, so the rigidity of [A] polymer can be moderately adjusted, and the dissociation property of the above-mentioned acid dissociable group is further improved, and the dissolution contrast can be further improved, so that the photoresist can be combined at a higher level. The LWR performance and EL performance of the composition.

From the viewpoint of the copolymerization property of the monomer providing the structural unit (I), R ^{3 is} preferably a hydrogen atom or a methyl group, more preferably a methyl group.

The structural unit (I) is, for example, a structural unit represented by the following formulas (1-1) to (1-12).

In the above formulae (1-1) to (1-12), the R ³ system is synonymous with the above formula (1).

In this case, the LWR property and the EL property of the photoresist composition can be combined at a higher level, and therefore it is preferred to have a bridged bivalent alicyclic hydrocarbon group. The structural unit is more preferably a structural unit having an adamantanediyl group, more preferably a structural unit having an adamantanediyl group and a monocyclic monovalent alicyclic hydrocarbon group, particularly preferably having the above formula (1-1), The structural unit represented by the formula (1-2), the formula (1-3), and the formula (1-4) is particularly preferably a structural unit represented by the above formula (1-1) and formula (1-2).

The lower limit of the content ratio of the structural unit (I) is relative to the composition [A] The total structural unit of the polymer, preferably 1 mol%, more preferably 3 mol%, more preferably 5 mol%, and particularly preferably 8 mol%. The upper limit of the content ratio of the structural unit (I) is preferably 70 mol%, more preferably 50 mol%, still more preferably 40 mol%. When the content ratio of the structural unit (I) is in the above range, the LWR performance and the EL performance of the photoresist composition can be improved. When the content ratio of the structural unit (I) is less than the above lower limit, the effect of improving the LWR performance and the EL performance of the photoresist composition may be lowered. On the other hand, when the content ratio of the structural unit (I) exceeds the above upper limit, the pattern formation property of the photoresist composition may be lowered.

[A] The polymer system is as described later, except that the above structural unit (I) is provided. In addition to the monomer, if necessary, it can be obtained by radical polymerization or the like together with a monomer which provides another structural unit. The synthesis method of the compound represented by the above formula (i) (hereinafter also referred to as "compound (i)") which provides the above structural unit (I) is as follows, and can be synthesized according to the following scheme (Scheme).

In the above formula, R ¹ is a divalent polycyclic alicyclic hydrocarbon group having 4 to 20 carbon atoms. R ² is a monovalent monocyclic or polycyclic alicyclic hydrocarbon group having 3 to 20 carbon atoms. R ³ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. Y is a halogen atom, a hydroxyl group or -OCOR'. R' is a monovalent organic group.

The polyglycol ketone and the Grignard reagent such as a cyclized naphthyl magnesium chloride can be obtained by reacting a carbon-carbon bond in a solvent such as diethyl ether or the like in the presence of a zinc compound such as zinc chloride (II). Compound. The alcohol compound is subjected to a condensation reaction with a (meth)acrylonitrile halide, (meth)acrylic acid or (meth)acrylic anhydride, for example, in the presence of a base such as an amine to obtain a compound (i).

[Structural Unit (II)]

The structural unit (II) is a structural unit represented by the above formula (2). [A] The polymer system contains the structural unit (II) in addition to the structural unit (I) as an acid-dissociable group, and its rigidity can be adjusted to make the solubility moderate. As a result, the dissolution contrast of the photoresist composition can be improved, so that the LWR performance and the EL performance of the photoresist composition can be combined at a higher level.

In the above formula (2), R ⁴ is a monovalent chain hydrocarbon group having 1 to 10 carbon atoms. R ⁵ and R ⁶ are each independently a monovalent chain hydrocarbon group having 1 to 10 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms; or R ⁵ and R ^{6 are} bonded to each other to be bonded thereto. The carbon atoms together form a divalent cyclic group having 3 to 20 carbon atoms. R ⁷ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

The above-mentioned R ⁴ represents a monovalent chain hydrocarbon group having 1 to 10 carbon atoms, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, and a sec-butyl group. a saturated hydrocarbon group such as t-butyl;

An unsaturated hydrocarbon group such as a vinyl group, a propenyl group, a butenyl group, an ethynyl group or a propynyl group.

The monovalent chain hydrocarbon group having 1 to 10 carbon atoms represented by the above R ⁵ and R ⁶ is, for example, the same as those exemplified as the monovalent chain hydrocarbon group having 1 to 10 carbon atoms represented by the above R ⁴ .

The above-mentioned R ⁵ and R ⁶ represent a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, for example,

a saturated monocyclic hydrocarbon group such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclodecyl or cyclododecyl; cyclopropenyl, cyclobutenyl, cyclopentyl An unsaturated polycyclic hydrocarbon group such as alkenyl, cyclohexenyl, cycloheptenyl or cyclodecenyl; bicyclo[2.2.1]heptyl (norbornyl), bicyclo[2.2.2]octyl, tricyclic [3.3.1.1 ^3,7 ] A saturated polycyclic hydrocarbon group such as a fluorenyl group; an unsaturated polycyclic hydrocarbon group such as a bicyclo [2.2.1] heptenyl group (nordenyl group) or a bicyclo [2.2.1] octenyl group; .

The above R ⁵ and R ⁶ may be bonded to each other to form a divalent cyclic group having 3 to 20 carbon atoms together with the carbon atoms bonded thereto, preferably an alicyclic hydrocarbon group or a heteroalicyclic group. It is substituted by an alkyl group, a fluorine atom, a polar group or the like. In the above, an alicyclic hydrocarbon group is preferable, and for example, a group in which one hydrogen atom is removed from the alicyclic hydrocarbon group represented by the above-mentioned R ⁵ and R ⁶ is exemplified.

The above R ^{7 is} preferably a hydrogen atom or a methyl group, more preferably a methyl group, from the viewpoint of the copolymerization property of the monomer providing the structural unit (II).

The structural unit (II) has, for example, a structural unit represented by the following formulas (2-1) to (2-4) (hereinafter also referred to as "structural unit (II-1) to (II-4))").

In the above formulae (2-1) to (2-4), R ⁴ , R ⁵ , R ⁶ and R ⁷ are synonymous with the above formula (2). n _p is an integer from 1 to 4.

n _{p is} preferably 1, 2 or 4, more preferably 1.

The structural unit (II-1) to (II-4) have, for example, a structural unit represented by the following formula.

In the above formula, R ⁷ is synonymous with the above formula (1).

The structural unit (II) is preferably a structural unit (II-1), a structural unit (II-2), and more preferably a structural unit (II-2) from the viewpoint of further improving the LWR performance and the EL performance of the photoresist composition. More preferably, it is a structural unit derived from 1-methyl-1-cyclopentyl (meth) acrylate, a structural unit derived from 1-ethyl-1-cyclopentyl (meth) acrylate.

The content of the structural unit (II) is preferably 0% by mole to 80% More than 10% by mole, more preferably 10% by mole to 80% by mole, more preferably 20% by mole to 65% by mole, and particularly preferably 30% by mole to 50% by mole. When the content ratio of the structural unit (II) is in the above range, the LWR performance and the EL performance of the photoresist composition can be combined at a higher level. When the content ratio of the structural unit (II) is less than the above lower limit, the effect of improving the LWR performance and the EL performance of the photoresist composition may be lowered. On the other hand, when the content ratio of the structural unit (II) exceeds the above upper limit, the adhesion pattern formed by the photoresist pattern may be lowered to the substrate or the like.

Structural unit (I) of a structural unit containing an acid dissociable group The total content of the structural unit (II) is preferably from 10 mol% to 80 mol%, more preferably from 10 mol% to 70 mol%, based on the total structural unit constituting the [A] polymer. More preferably 15% by mole to 65% by mole. When the total content ratio of the structural unit (I) to the structural unit (II) is in the above range, the LWR performance and the EL performance of the photoresist composition can be combined at a higher level.

[Structural Unit (III)]

The structural unit (III) contains a structural unit having at least one structure selected from the group consisting of a lactone structure, a cyclic carbonate structure, and a sultone structure. [A] The polymer contains a structural unit (III), and its solubility can be adjusted to be moderate. Further, the adhesion of the photoresist pattern formed by the photoresist composition to the substrate or the like can be improved. These results can improve the LWR performance and EL performance of the photoresist composition. Here, the lactone structure means a structure having one ring (lactone ring) having a group represented by -OC(O)-. Further, the cyclic carbonate structure means a structure having one ring (cyclic carbonate ring) containing a group represented by -OC(O)-O-. The sultone structure means a structure having one ring (sultone ring) containing a group represented by -OS(O) ₂ -.

The structural unit (III) is, for example, a structural unit represented by the following formula (3).

In the above formula (3), R ⁸ contains a monovalent group of a lactone structure, a monovalent group containing a cyclic carbonate structure, or a monovalent group having a sultone structure. R ⁹ is a single bond or a divalent linking group. R ¹⁰ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

The above R ⁸ represents a monovalent group having a lactone structure, a monovalent group having a cyclic carbonate structure, and a monovalent group having a sultone structure, and for example, the following formula (R8-1) to (R8-11) ) indicates the group and so on.

In the above formulae (R8-1) to (R8-4), R ^L1 is an oxygen atom or a methylene group. R ^L2 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. n _L1 is 0 or 1. n _L2 is an integer from 0 to 3.

In the above formulae (R8-7) and (R8-8), n _C1 is an integer of 0 to 2. The n _C2 ~ n _C5 systems are each independently an integer from 0 to 2.

In the above formula (R8-8) to (R8-11), R ^S1 is an oxygen atom or a methylene group. R ^S2 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. n _S1 is 0 or 1. n _S2 is an integer from 0 to 3.

In the above formulae (R8-1) to (R8-11), * represents a moiety bonded to R ^{4 of the} above formula (3).

Some or all of the hydrogen atoms of the group represented by the above formula (R8-1) to (R8-11) may be substituted.

In this case, R ^{8 is} preferably (R8-1), (R8-3), (R8-7) and (from the viewpoint of having a higher level of LWR performance and EL performance of the photoresist composition. The group represented by R8-9) is more preferably a group represented by (R8-1) or (R8-7), more preferably a group represented by (R8-1).

The above R ^L1 and R ^{S1 are} preferably a methylene group. The above R ^L2 and R ^{S2 are} preferably a hydrogen atom. The above n _L1 and n _{S1 are} preferably 0. The above n _L2 and n _{S2 are} preferably 1 or 2, more preferably 1.

The group which replaces the hydrogen atom of the norbornane ring of the group represented by the above (R8-1) and (R8-7) is preferably a cyano group, a trifluoromethyl group or a methoxycarbonyl group, more preferably Cyano group.

The divalent linking group represented by the above R ^{9 may} , for example, be a divalent linear or branched hydrocarbon group having 1 to 20 carbon atoms, and one or more of the hydrocarbon groups may be selected from -CO-, -O-, -NH- And a group formed by at least one group of -S- groups.

The above R ^{10 is} preferably a hydrogen atom or a methyl group, more preferably a methyl group, from the viewpoint of the copolymerization property of the monomer providing the structural unit (III).

The structural unit (III) has, for example, a structural unit represented by the following formula Wait.

In the above formula, R ¹⁰ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

Providing a monomer of structural unit (III), for example, having the following formula (3- m) indicates a monomer or the like.

In the above formula (3-m), R ⁸ , R ⁹ and R ¹⁰ are synonymous with the above formula (3).

R ⁸ , R ⁹ and R ¹⁰ in the above formula (3-m) have, for example, the same groups as those exemplified for the respective groups in the above formula (3).

The proportion of the structural unit (III) is preferably 20 moles. %~80% by mole, more preferably 30% by mole to 70% by mole, more preferably 35% by mole to 655% by mole. When the content ratio of the structural unit (III) is in the above range, the LWR performance and the EL performance of the photoresist composition can be combined at a higher level. The adhesion of the formed photoresist pattern to the substrate can be improved. When the content ratio of the structural unit (III) is less than the above lower limit, the adhesion pattern formed on the substrate may be lowered in adhesion. When the content ratio of the structural unit (III) exceeds the above upper limit, the pattern formation property of the photoresist composition may be lowered.

[Structural Unit (IV)]

The structural unit (IV) is a structural unit containing a polar group. [A] The polymer further contains a structural unit (IV), which can appropriately adjust the solubility of the [A] polymer, and can improve the dissolution contrast. As a result, the LWR performance and the EL performance of the photoresist composition can be combined at a higher level. .

The above polar group is, for example, a hydroxyl group, a carboxyl group, a cyano group or a carbonyl group. , nitro, sulfonamide, and the like. Among these, a hydroxyl group, a carboxyl group, a carbonyl group is preferred, and a hydroxyl group is more preferred.

The structural unit (IV) has, for example, a structural unit represented by the following formula Wait.

In the above formula, R ¹¹ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

Among these, it is preferably a structural unit containing a hydroxyl group, more preferably It is a structural unit having a hydroxyl group and an adamantane skeleton, and more preferably a structural unit derived from 3-hydroxy-1-adamantyl (meth)acrylate.

The content of the structural unit (IV) is preferably 0% by mole to 30% Molar%, more preferably 0% by mole to 255% by mole, more preferably 5% by mole to 255% by mole. When the content ratio of the structural unit (IV) is in the above range, the LWR performance and the EL performance of the photoresist composition can be combined at a higher level.

[Structural Unit (F-I)]

The structural unit (F-I) is a structural unit represented by the following formula (C1). The structural unit (F-I) contains a fluorine atom, and particularly when the [A] polymer is used as a water-repellent additive, it preferably has a structural unit (F-I).

In the above formula (C1), R ¹² is an alkyl group having 1 to 6 carbon atoms of at least one fluorine atom, a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or a derivative thereof. A is a single bond or a divalent linking group. R ¹³ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

The above R ¹² represents an alkyl group having 1 to 6 carbon atoms and having at least one fluorine atom, and examples thereof include a fluoromethyl group, a difluoromethyl group, a perfluoromethyl group, a difluoroethyl group, a trifluoroethyl group, and a perfluoroethyl group. Base, trifluoro-n-propyl, pentafluoro-n-propyl, hexafluoro-i-propyl, difluoro-sec-butyl, trifluoro-sec-butyl, and the like.

The above R ¹² represents a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms and having at least one fluorine atom, and examples thereof include a fluorocyclopropyl group, a fluorocyclobutyl group, a fluorocyclopentyl group, a difluorocyclopentyl group, and a tetrafluoro group. Cyclopentyl, perfluorocyclopentyl, difluorocyclohexyl, perfluorocyclohexyl and the like.

The above-mentioned alkyl group of R ¹² or a derivative of a monovalent alicyclic hydrocarbon group, for example, a hydrogen atom or a fluorine atom which the above-mentioned alkyl group or a monovalent alicyclic hydrocarbon group has is substituted by a group containing an alkali-dissociable group. Group and so on. The "alkali dissociable group" refers to a group in which a hydrogen atom of a polar group such as a hydroxyl group or a carboxyl group is substituted, and a group which is dissociated in the presence of a base (for example, a 2.38 mass% tetramethylammonium hydroxide aqueous solution at 23 ° C) is used. The group containing an alkali-dissociable group may, for example, be -COOR'(R'-based alkyl group having 1 to 6 carbon atoms).

The above-mentioned A represents a divalent linking group, for example, an oxygen atom, a divalent alicyclic ring such as a sulfur atom, a carbonyloxy group, an oxycarbonyl group, a decylamino group, a sulfonyl sulfoximine group, a urethane group, an alkanediyl group such as a methane diyl group or a cyclopentanediyl group A divalent aromatic hydrocarbon group such as a divalent aromatic hydrocarbon group such as a hydrocarbon group, a benzenediyl group or a naphthyldiyl group, or a divalent group containing a lactone structure such as a lactone structure, or a group in which one of these groups is combined.

Providing preferred monomers of the above structural units (F-I), for example There are trifluoromethyl (meth) acrylate, 2, 2, 2-trifluoroethyl (meth) acrylate, perfluoroethyl (meth) acrylate, perfluoro-n-propyl (meth) acrylate , perfluoro i-propyl (meth) acrylate, perfluoro-n-butyl (meth) acrylate, perfluoro i-butyl (meth) acrylate, perfluoro t-butyl (meth) acrylate Ester, 2-(1,1,1,3,3,3-hexafluoropropyl)(meth)acrylate, 1-(2,2,3,3,4,4,5,5-octafluoro Pentyl)(meth)acrylate, perfluorocyclohexylmethyl(meth)acrylate, 1-(2,2,3,3,3-pentafluoropropyl)(meth)acrylate, 1- (3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyl)(meth)acrylate, 1- (5-trifluoromethyl-3,3,4,4,5,6,6,6-octafluorohexyl) (A Acrylate, 2,2,2-trifluoroethoxycarbonylmethyl(meth)acrylate, 1-ethoxycarbonyl-1,1-difluoro-2-butyl(meth)acrylate , 2,2,2-trifluoroethoxycarbonylnorbornane (meth) acrylate, 2-(2,2,2-trifluoroethoxycarbonylmethyloxy)-6-ethylene Keina et al.

The structural unit (F-I) content ratio is relative to the composition [A] The total structural unit of the compound is preferably 5 mol% or more, more preferably 20 mol% or more, still more preferably 30 mol% or more, and particularly preferably 50 mol% or more. When the content ratio of the structural unit (FI) is less than 5 mol%, the surface of the photoresist film formed by the photoresist composition may have a back contact angle of less than 70 degrees, and the photoresist may not be suppressed. Unfavorable conditions such as dissolution of an acid generator such as a film.

[Other structural units]

The [A] polymer may contain other structural units other than the above structural units (I) to (IV) and structural units (F-I), for example, a structural unit containing a non-acid dissociable alicyclic hydrocarbon group. The content ratio of the other structural unit is preferably 20 mol% or less, more preferably 10 mol% or less.

The photoresist composition may contain one or more kinds of [A] poly Compound. The content of the [A] polymer as the base polymer is preferably 70% by mass or more, and more preferably 80% by mass or more based on the total solid content of the photoresist composition. The content of the [A] polymer as the water-repellent additive is relative to the base polymer (the [A] polymer as the base polymer and/or the [C2] other polymer described later as the [C2] acid-dissociable group) 100 parts by mass of the polymer, etc., preferably 0.1 parts by mass to 30 parts by mass, more preferably 0.5 mass It is preferably 20 parts by mass, more preferably 1 part by mass to 10 parts by mass.

<[A] Synthesis Method of Polymer>

The [A] polymer can be produced, for example, by polymerizing a monomer corresponding to each predetermined structural unit using a polymerization initiator such as a radical polymerization initiator in a suitable solvent. For example, a solution containing a monomer and a radical polymerization initiator is dropped into a solution containing a polymerization solvent or a monomer to carry out a polymerization reaction, and a solution containing a monomer and a solution containing a radical polymerization initiator are each Do not drip into a solution containing a polymerization solvent or a monomer, carry out a polymerization reaction, and separately drop a solution containing a plurality of monomers and a solution containing a radical polymerization initiator to each other to contain a polymerization solvent or a single In the solution of the body, it is preferred to carry out the synthesis by a method such as a polymerization reaction.

The above polymerization solvent is, for example, an alkane such as n-pentane, n-hexane, n-heptane, n-octane, n-decane or n-decane; cyclohexane, cycloheptane, cyclooctane, decahydronaphthalene, or An alkane such as decane; an aromatic hydrocarbon such as benzene, toluene, xylene, ethylbenzene or cumene; chlorobutane, bromohexane, dichloroethane, hexamethylene dibromide, Halogenated hydrocarbons such as chlorobenzene; saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, isobutyl acetate, methyl propionate; acetone, 2-butanone, 4-methyl-2-pentanone, 2 a ketone such as heptanone; Ethers such as tetrahydrofuran, dimethoxyethane and diethoxyethane; alcohols such as methanol, ethanol, 1-propanol, 2-propanol and 4-methyl-2-pentanol. These polymerization solvents may be used singly or in combination of two or more.

The reaction temperature in the above polymerization may be appropriately determined depending on the type of the radical initiator, but it is usually 40 ° C to 150 ° C, preferably 50 ° C to 120 ° C. The reaction time is usually from 1 hour to 48 hours, preferably from 1 hour to 24 hours.

The above radical polymerization initiators are, for example, azobisisobutyronitrile (AIBN), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2' - azobis(2-cyclopropylpropionitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylpropionitrile) Wait. These radical polymerization initiators may be used alone or in combination of two or more.

The polymer obtained by the polymerization reaction is preferably recovered by a reprecipitation method. That is, after the completion of the polymerization reaction, the polymerization liquid is put into a reprecipitation solvent, and the intended polymer is recovered as a powder. The reprecipitation solvent may be used singly or in combination of two or more kinds of alcohols or alkanes. In addition to the reprecipitation method, a low molecular component such as a monomer or an oligomer can be removed by a liquid separation operation, a column operation, or an ultrafiltration operation to recover a polymer.

[A] The weight average molecular weight (Mw) of the polymer measured by gel permeation chromatography (GPC), preferably from 1,000 to 100,000, more preferably from 1,000 to 30,000, still more preferably from 2,000 to 20,000. , especially good for 3,000~10,000. Also, [A] polymer The Mw is in the above specific range, and the LWR performance and the EL performance of the photoresist composition can be further improved.

Further, the ratio (Mw/Mn) of the Mw of the [A] polymer to the number average molecular weight (Mn) is usually from 1 to 5, preferably from 1 to 3, more preferably from 1 to 2, still more preferably from 1 to 1.5. By setting Mw/Mn in the above range, the LWR performance and the EL performance of the photoresist composition can be further improved.

Moreover, Mw and Mn in this specification utilize GPC tubes. Column (G2000HXL 2, G3000HXL 1 , G4000HXL 1 , the above is made of TOSOH), flow rate 1.0 ml / min, solvent: tetrahydrofuran, sample concentration: 1.0% by mass, sample injection amount: 100 μL, column temperature: 40 For the analysis conditions of °C, the detector uses a differential refractometer and the value measured by GPC using monodisperse polystyrene as a standard.

[A] Low molecular weight content in polymer (molecular weight 1,000 The ratio (% by mass) of the following part is preferably 5% by mass or less, more preferably 1% by mass or less, still more preferably 0.5% by mass or less, and particularly preferably 0.2% by mass or less. When the low molecular weight content of the polymer in the above [A] is in the above range, the lithographic properties such as the LWR performance of the photoresist composition can be improved.

Further, the low molecular weight content (% by mass) in the [A] polymer was obtained by high-speed liquid chromatography (HPLC), and the column was subjected to Intersil ODS-25 μm (4.6 mm). ×250mm) (manufactured by GL SCIENCE), flow rate: 1.0 mL/min, elution solvent: acrylonitrile/0.1% by mass phosphoric acid, sample concentration: 1.0% by mass, sample injection amount: 100 μL of analysis conditions, and the detector uses differential refraction Calculate the value of the measurement.

<[B]acid generator>

[B] An acid generating system irradiates an acid generating compound by an exposure light source. By the acid branching, the acid dissociable group in the [A] polymer is dissociated to generate a polar group such as a carboxyl group, and as a result, the solubility of the [A] polymer to the developing liquid branch is changed. [B] The form of the acid generator may be in the form of a compound as described later (hereinafter also referred to as "[B] acid generator") or a form in which a part of the polymer is incorporated, and both forms may be used. .

[B] an acid generator such as a phosphonium salt compound, N-sulfonyloxy group A quinone imine compound, a halogen-containing compound, a diazoketone compound, or the like.

An onium salt compound, for example, a phosphonium salt, a tetrahydrothiophene salt, Barium salts, barium salts, diazonium salts, pyridinium salts and the like.

The phosphonium salt is, for example, triphenylsulfonium trifluoromethanesulfonate or triphenylbenzene. Based on nonafluoro-n-butanesulfonate, triphenylsulfonium perfluoro-n-octanesulfonate, triphenylsulfonium 2-bicyclo[2.2.1]hept-2-yl-1,1, 2,2-tetrafluoroethane sulfonate, triphenylsulfonium 2-bicyclo[2.2.1]hept-2-yl-1,1-difluoroethanesulfonate, triphenylphosphonium adenyl- 1-oxycarbonyldifluoromethanesulfonate, triphenylsulfonium 2-(adamantan-1-yl)-1,1-difluoroethane-1-sulfonate, triphenylsulfonium 6- (King Kong Alkyl-1-ylcarbonyloxy)-1,1,2,2-tetrafluorohexane-1-sulfonate, 4-cyclohexylphenyldiphenylphosphonium trifluoromethanesulfonate, 4-cyclohexyl Phenyldiphenylphosphonium nonabutanesulfonate, 4-cyclohexylphenyldiphenylphosphonium perfluoro-n-octanesulfonate, 4-cyclohexylphenyldiphenylphosphonium 2- Bicyclo[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 4-methanesulfonylphenyldiphenylphosphonium trifluoromethanesulfonate, 4-methane Sulfophenyl phenyl diphenyl sulfonium hexafluoro-n-butane sulfonate, 4-methanesulfonyl phenyl diphenyl fluorene perfluoro-n-octane sulfonate, 4-methyl Alkylsulfonylphenyldiphenylphosphonium 2-bicyclo[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, and the like.

The tetrahydrothiophene sulfonium salt is, for example, 1-(4-n-butoxynaphthalen-1-yl)tetra Hydrothienyl trifluoromethanesulfonate, 1-(4-n-butoxynaphthalen-1-yl)tetrahydrothiophene nonafluoro-n-butanesulfonate, 1-(4-n-butoxy Naphthyl-1-yl)tetrahydrothiophene perfluoro-n-octane sulfonate, 1-(4-n-butoxynaphthalen-1-yl)tetrahydrothiophene 2-cyclo[2.2.1] Hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1-(6-n-butoxynaphthalen-2-yl)tetrahydrothiophene trifluoromethanesulfonate, 1 -(6-n-butoxynaphthalen-2-yl)tetrahydrothiophene nonabutanesulfonate, 1-(6-n-butoxynaphthalen-2-yl)tetrahydrothiophene Perfluoro-n-octanesulfonate, 1-(6-n-butoxynaphthalen-2-yl)tetrahydrothiophene 2-cyclobi[2.2.1]hept-2-yl-1,1,2 , 2-tetrafluoroethane sulfonate, 1-(3,5-dimethyl-4-hydroxyphenyl)tetrahydrothiophene trifluoromethanesulfonate, 1-(3,5-dimethyl- 4-hydroxyphenyl)tetrahydrothiophene nonabutanesulfonate, 1-(3,5-dimethyl-4-hydroxyphenyl)tetrahydrothiophene perfluoro-n-octanesulfonate Acid ester, 1-(3,5-dimethyl-4-hydroxyphenyl)tetrahydrothiophene 2-cyclobi[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethane Sulfonate and the like.

The phosphonium salt is, for example, diphenylsulfonium trifluoromethanesulfonate or diphenyl. Based on nonafluoro-n-butanesulfonate, diphenylphosphonium perfluoro-n-octanesulfonate, bis(4-t-butylphenyl)phosphonium trifluoromethanesulfonate, double (4 -t-butylphenyl)nonafluoro-n-butanesulfonate, bis(4-t-butylphenyl)phosphonium perfluoro-n-octanesulfonate, bis(4-t-butyl) Phenylphenyl) indole 2-bicyclo[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate and the like.

Among these, a phosphonium salt is preferred, and a phosphonium salt or a tetrahydrothiophene is more preferred. It is better to use strontium salt, especially triphenyl sulfonium salt, especially triphenyl hydrazine. Adamantyl-1-oxycarbonyldifluoromethanesulfonate, triphenylsulfonium 2-(adamantan-1-yl)-1,1-difluoroethane-1-sulfonate, triphenylsulfonium 6-(adamantan-1-ylcarbonyloxy)-1,1,2,2-tetrafluorohexane-1-sulfonate.

[B] The acid generator may be used alone or in combination of two or more. use. The content of the [B] acid generator in the case of the [B] acid generator is preferably from 100 parts by mass of the [A] polymer from the viewpoint of ensuring the sensitivity and developability of the photoresist of the photoresist composition. It is 0.1 part by mass or more and 30 parts by mass or less, more preferably 0.5 part by mass or more and 20 parts by mass or less, more preferably 1 part by mass or more and 15 parts by mass or less, and particularly preferably 5 parts by mass or more and 15 parts by mass or less. When the content of the [B] acid generator is less than 0.1 part by mass, the sensitivity tends to be insufficient, and when it exceeds 30 parts by mass, the transparency to the exposure light is lowered, and it may be difficult to obtain the desired photoresist pattern.

<[C]Other polymers>

The photoresist composition may contain, in addition to the [A] polymer, another polymer [C] having no structural unit (I). For example, when the [A] polymer is a base polymer, the other polymer as [C] may contain a water-repellent additive (hereinafter also referred to as "[C1] a polymer containing a fluorine atom"). Further, when the [A] polymer is a water-repellent additive, the other polymer (C) may contain a base polymer (hereinafter also referred to as "[C2] polymer containing an acid-dissociable group"). The photoresist composition may be used as a base polymer in combination with [A] a polymer and [C2] a polymer having an acid dissociable group, and may be used as a water-repellent additive in combination with [A] a polymer and [C1] containing a fluorine atom. The polymer.

The following describes [C1] a polymer containing a fluorine atom and an acid containing [C2] Dissociable group of polymers.

[[C1] Polymer containing fluorine atom]

The resist composition is used, for example, in liquid immersion exposure, etc., and when [A] the polymer is a base polymer, it is preferable to further contain [C1] a polymer containing a fluorine atom. The photoresist composition contains a polymer containing a fluorine atom in [C1], and when a photoresist film is formed, the polymer having a fluorine atom in [C1] is characterized in that it has a tendency to be distributed on the surface of the photoresist film. Therefore, when the liquid immersion is exposed, it is possible to suppress the [B] acid generator in the photoresist film or the [D] acid diffusion control body described later from being dissolved in the liquid immersion medium. Further, since the photoresist composition contains [C1] a polymer containing a fluorine atom, the surface of the photoresist film formed has a rising receding contact angle, and the liquid immersion exposure can be smoothly performed, and the scanning can be performed at a high speed.

[C1] The fluorine atom content of the polymer containing a fluorine atom is preferably higher than the fluorine atom content of the [A] polymer. [C1] The fluorine atom-containing polymer has a higher fluorine atom content than the [A] polymer, and is effective in the surface layer of the photoresist film in which [C1] a fluorine atom-containing polymer is formed, and the result is more versatile. The effect of the above immersion exposure. [C1] The fluorine atom content of the polymer containing a fluorine atom is preferably 1% by mass or more, more preferably 3% by mass or more, and still more preferably 5% by mass or more. Further, the fluorine atom content (% by mass) of the polymer was determined by ¹³ C-NMR to determine the structure of the polymer, and the results were calculated.

[C1] The polymer containing a fluorine atom can be usually formed by polymerizing one type or more of a monomer having a fluorine atom other than the monomer which provides the structural unit (I) in the structure.

[C1] A fluorine-containing polymer structure contains a fluorine atom The structural unit is preferably [A] a polymer and has the above structural unit (F-I). The content ratio of the structural unit (FI) is preferably 5 mol% or more, more preferably 10 mol% or more, and more preferably 20 mol%, based on the total structural unit of the polymer constituting [C1] containing a fluorine atom. More than %, especially preferably 30% or more. When the content ratio of the structural unit (FI) is less than 5 mol%, the receding contact angle of the surface of the photoresist film formed by the photoresist composition may sometimes be less than 70 degrees, and sometimes the photoresist film may not be suppressed. A problem such as dissolution of an acid generator or the like.

Further, [C1] a polymer containing a fluorine atom may be contained in the structure A structural unit other than the structural unit of a fluorine atom. [C1] The fluorine atom-containing compound may contain one or more of these structural units.

[Other structural units]

[C1] The polymer containing a fluorine atom may contain one or more types of structural units other than the structural unit of the fluorine atom in the structure, and may have acid dissociation, for example, in order to control the dissolution rate of the developing solution. a structural unit of a group, a structural unit containing at least one structure selected from the group consisting of a lactone structure, a cyclic carbonate structure, and a sultone structure, a structural unit containing a polar group such as a hydroxyl group or a carboxyl group, and an alicyclic ring The structural unit of the formula, the structural unit derived from the aromatic compound, etc., in order to suppress scattering of light caused by reflection of the substrate.

a structural unit having the above acid dissociable group, for example, [A] Structural unit of the polymer (II) The same structural unit and the like.

The structural unit containing at least one structure selected from the group consisting of the above-described lactone structure, cyclic carbonate structure, and sultone structure has, for example, the same structural unit as the structural unit (III) of the [A] polymer.

The structural unit containing the above polar group may have, for example, the same structural unit as the structural unit (IV) of the [A] polymer.

The structural unit containing the above alicyclic group is, for example, a structural unit represented by the following formula (C2).

In the above formula (C2), R ¹⁴ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. X is a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms.

The above-mentioned X represents a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, and examples thereof include cyclobutane, cyclopentane, cyclohexane, bicyclo [2.2.1] heptane, bicyclo [2.2.2] octane, and tri In the alicyclic hydrocarbons such as [5.2.1.0 ^2,6 ]decane, tetracyclo[6.2.1.1 ^3,6 .0 ^2,7 ]dodecane, tricyclo[3.3.1.1 ^3,7 ]decane A group or the like from which one hydrogen atom is removed. Part or all of one of the hydrogen atoms of the monovalent alicyclic hydrocarbon group may be methyl, ethyl, n-propyl, i-propyl, n-butyl, 2-methylpropyl, 1- a linear or branched alkyl group having a carbon number of 1 to 4, a cycloalkyl group having 3 to 10 carbon atoms, a hydroxyl group, a cyano group, and a hydroxyl group having 1 to 10 carbon atoms; Alkyl or carboxyl substituted. Further, two hydrogen atoms bonded to the same carbon atom may be substituted with one oxygen atom to form a ketone group.

Preferred monomers having a structural unit containing the above alicyclic group are, for example, (meth)acrylic acid-bicyclo[2.2.1]hept-2-yl ester, (meth)acrylic acid-bicyclo[2.2.2] octyl -2-yl ester, (meth)acrylic acid-tricyclo[5.2.1.02,6]non-7-yl ester, (meth)acrylic acid-tetracyclo[6.2.1.13,6.0 ^2,7 ]dodecane- 9-yl ester, (meth)acrylic acid-tricyclo[3.3.1.1 ^3,7 ]non-1-yl ester, (meth)acrylic acid-tricyclo[3.3.1.1 ^3,7 ]non-2-yl ester .

Providing a structural unit derived from the above aromatic compound Preferred monomers, for example, styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-methoxystyrene, 3-methoxy Styrene, 4-methoxystyrene, 4-(2-t-butoxycarbonylethoxy)styrene 2-hydroxystyrene, 3-hydroxystyrene, 4-hydroxystyrene, 2-hydroxy- Α-methylstyrene, 3-hydroxy-α-methylstyrene, 4-hydroxy-α-methylstyrene, 2-methyl-3-hydroxystyrene, 4-methyl-3-hydroxystyrene , 5-methyl-3-hydroxystyrene, 2-methyl-4-hydroxystyrene, 3-methyl-4-hydroxystyrene, 3,4-dihydroxystyrene, 2,4,6-three Hydroxystyrene, 4-t-butoxystyrene, 4-t-butoxy-α-methylstyrene, 4-(2-ethyl-2-propoxy)styrene, 4-(2 -ethyl-2-propoxy)-α-methylstyrene, 4-(1-ethoxyethoxy)styrene, 4-(1-ethoxyethoxy)-α-methyl Styrene, phenyl (meth) acrylate, benzyl (meth) acrylate, hydrazine, 5-hydroxyindole, 1-vinylnaphthalene, 2-vinylnaphthalene, 2-hydroxy-6-vinylnaphthalene, 1- Naphthyl (meth) acrylate, 2-naphthyl (meth) acrylate, 1-naphthyl (meth) acrylate, 1-mercapto (meth) acrylate, 2-mercapto (meth) acrylate, 9-fluorenyl (meth) acrylate, 9-fluorenylmethyl (methyl) ) Acrylate, 1-vinyl anthracene.

The above other structural units usually have a content ratio of 80 m. % or less, preferably 75 mol% or less.

[C1] The content of the polymer containing a fluorine atom is preferably 0.1 part by mass to 30 parts by mass, more preferably 0.5 part by mass to 20 parts by mass, even more preferably 1 part by mass based on 100 parts by mass of the [A] polymer. ~10 parts by mass.

<[C1] Synthesis method of polymer containing fluorine atom>

[C1] The polymer containing a fluorine atom can be synthesized, for example, by polymerizing a monomer corresponding to each structural unit in a predetermined solvent using a radical polymerization initiator. [C1] The radical polymerization initiator, the polymerization solvent, and the like used for the synthesis of the polymer containing a fluorine atom are the same as those exemplified for the synthesis method of the above [A] polymer.

The reaction temperature in the above polymerization is usually from 40 ° C to 150 ° C. It is preferably 50 ° C ~ 120 ° C. The reaction time is usually from 1 hour to 48 hours, preferably from 1 hour to 24 hours.

[C1] Polyphenylene with a fluorine atom-containing polymer by GPC method The weight average molecular weight (Mw) in terms of ethylene is preferably from 1,000 to 50,000, more preferably from 3,000 to 30,000, still more preferably from 5,000 to 20,000. [C1] When the Mw of the polymer containing a fluorine atom does not reach the above lower limit, a sufficient advancing contact angle may not be obtained on the surface of the photoresist film formed. Moreover, when Mw exceeds the above upper limit, the developability of the obtained photoresist composition tends to be lowered.

[C1] The Mw/Mn ratio of the polymer containing a fluorine atom is usually from 1 to 3, preferably from 1 to 2.5, more preferably from 1 to 2.

[[C2] Polymer containing acid dissociable group]

When the photoresist composition contains, for example, a [A] polymer as a water-repellent additive, it is preferably a [C2] acid-dissociable group-containing polymer containing [C] other polymer as a base polymer.

[C2] The polymer containing an acid dissociable group is contained as long as it contains When the structural unit of the acid dissociable group other than the structural unit (I) is not particularly limited, the structural unit containing the acid dissociable group may, for example, be a structural unit (II) in the [A] polymer. [C2] The content ratio of the structural unit containing the acid dissociable group in the polymer having an acid dissociable group is preferably 20 mol% based on the total structural unit of the polymer constituting the acid dissociable group of [C2]. ~80% by mole, more preferably 30% by mole to 70% by mole. Further, [C2] the polymer having an acid-dissociable group preferably further contains a structural unit (III) in the [A] polymer, and may further contain a structural unit (IV).

<[C2] Synthesis method of polymer containing acid dissociable group>

[C2] The polymer containing an acid dissociable group can be synthesized by the same method as the synthesis method of the above [A] polymer. [C2] The preferred range of the Mw, Mw/Mn ratio, and low molecular weight content of the polymer having an acid dissociable group is also the same as that of the above [A] polymer.

<[D] Acid Diffusion Control Body>

The [D] acid diffusion control system controls a component which exhibits an effect of suppressing a poor chemical reaction in an unexposed portion by exposing the diffusion phenomenon of an acid generated by the [B] acid generator in the photoresist film. Photoresist composition containing [D] acid diffusion The control body can improve the resolution and storage stability of the obtained photoresist composition, and can further suppress the change in the line width of the photoresist pattern caused by the change in the standing time from exposure to development processing, and can be obtained. A photoresist composition with excellent process stability. [D] The form of the acid diffusion controlling body may be a form of a free compound (hereinafter sometimes referred to as "[D] acid diffusion controlling agent") or a form in which a part of the polymer is incorporated, and the form of both Can be.

[D] an acid diffusion controlling agent such as an amine compound or a guanamine group a compound, a urea compound, a nitrogen-containing heterocyclic compound, or the like.

The amine compound is, for example, a mono(cyclo)alkylamine; a di(cyclo)alkylamine; a tri(cyclo)alkylamine; a substituted alkylaniline such as 2,6-diisopropylaniline or a derivative thereof; ethylenediamine, N,N,N',N'-tetramethylethylenediamine, Butanediamine, hexamethylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 4,4'-diaminobenzophenone, 4,4 '-Diaminodiphenylamine, 2,2-bis(4-aminophenyl)propane, 2-(3-aminophenyl)-2-(4-aminophenyl)propane, 2- (4-Aminophenyl)-2-(3-hydroxyphenyl)propane, 2-(4-aminophenyl)-2-(4-hydroxyphenyl)propane, 1,4-double [1- (4-Aminophenyl)-1-methylethyl]benzene, 1,3-bis[1-(4-aminophenyl)-1-methylethyl]benzene, bis(2-dimethyl Aminoethyl ethyl ether, bis(2-diethylaminoethyl)ether, 1-(2-hydroxyethyl)-2-imidazolidinone, 2-quinoxalinol, N, N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine, N,N,N',N",N"-pentamethyldiethylenetriamine, triethanolamine, and the like.

Amidoxime-containing compound such as t-butyl-4-hydroxy-1-piperidinecarboxylate An N-t-pentyloxycarbonyl group-containing amine group such as a N-tert-butoxycarbonylamino group-containing compound or a t-pentyl-4-hydroxy-1-piperidinecarboxylate such as a carboxylate Compound, formamide, N-methylformamide, N,N-dimethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, propylene Amine, benzoguanamine, pyrrolidone, N-methylpyrrolidone, N-ethinyl-1-adamantylamine, isocyanuric acid tris(2-hydroxyethyl) ester, and the like.

Urea compounds such as urea, methyl urea, 1,1-dimethylurea , 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, tri-n-butylthiourea, and the like.

Nitrogen-containing heterocyclic compounds such as imidazoles; pyridines; piperazines Class; pyrazine, pyrazole, pyridazine, quinozaline, hydrazine, pyrrolidine, piperidine, 4-hydroxy-N-pentyloxycarbonyl piperidine, piperidine ethanol, 3-piperidinyl-1 , 2-propanediol; morpholine, 4-methylmorpholine, 1-(4-morpholinyl)ethanol, 4-ethionylmorpholine, N-(2-cyclohexylcarbonyloxyethyl)morpholine, a morpholine such as 3-(N-morpholinyl)-1,2-propanediol; 1,4-dimethylpiperazine, 1,4-diazabicyclo[2.2.2]octane, and the like.

Among these, an amine compound and a guanamine-containing compound are preferred. More preferably, it is a substituted alkyl aniline, an Nt-pentyloxycarbonyl-containing amine compound, more preferably t-pentyl-4-hydroxy-1-piperidinecarboxylate, 2,6-diisopropylaniline .

Also, the [D] acid diffusion control agent can also be produced by exposure Photodegradability base of weak acid. The photodegradable base exhibits an acid capturing function by an anion in the unexposed portion, and functions as an inhibitor to capture an acid diffused by the exposed portion. An acid is generated in the exposed portion to destroy the anion, so the acid trapping function disappears. In other words, it has a function as an inhibitor only in the unexposed portion, thus improving the contrast of the dissociation reaction of the acid dissociable group. As a result, the lithographic performance of the resolution of the photoresist composition and the like can be further improved. The photodegradable base is, for example, an onium salt compound which loses acid diffusion controllability by exposure decomposition. The onium salt compound is, for example, an onium salt compound represented by the following formula (D1), an onium salt compound represented by the following formula (D2), and the like.

In the above formula (D1) and formula (D2), R ¹⁵ to R ¹⁹ each independently represent a hydrogen atom, an alkyl group, an alkoxy group, a hydroxyl group, a halogen atom or -SO ₂ -R ^A . R ^A is an alkyl group, a cycloalkyl group, an alkoxy group or an aryl group. Z ^- and E ^- systems OH ^- , R ^B -COO ^- , R ^C -SO ₂ -N ^- -R ^B , R ^B -SO ₃ ^- or an anion represented by the following formula (D3). R ^B is a linear or branched alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms, and an aralkyl group having 7 to 30 carbon atoms. Some or all of the hydrogen atoms of the above alkyl group, cycloalkyl group, aryl group and aralkyl group may be substituted. R ^C is a linear or branched alkyl group having 1 to 10 carbon atoms and a cycloalkyl group having 3 to 20 carbon atoms. Some or all of the hydrogen atoms of the above alkyl group and cycloalkyl group may be substituted by a fluorine atom. However, when Z ^- is R ^B -SO ₃ ^- , there is no fluorine atom bonding on the carbon atom to which SO ₃ ^- is bonded.

In the above formula (D3), a linear or branched alkyl group having 1 to 12 carbon atoms or a linear chain having 1 to 12 carbon atoms in which some or all of the hydrogen atoms of R ²⁰ are substituted by fluorine atoms Or branched alkoxy groups. u is an integer from 0 to 2.

R ¹⁵ to R ¹⁹ in the above formulae (D1) and (D2) are preferably a hydrogen atom or -SO ₂ -R ^A . Further, the above R ^{A is} preferably a cycloalkyl group, more preferably a cyclohexyl group.

The above alkyl group represented by R ^B , for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group or the like and a part or all of the hydrogen atoms of the groups are substituted The group and so on.

The above cycloalkyl group represented by R ^B is, for example, a cyclopentyl group, a cyclohexyl group, a decyl group, a tricyclodecyl group, a tetracyclododecyl group, an adamantyl group or the like and a part or all of the hydrogen atoms of the groups Substituted groups, etc.

Examples of the aryl group represented by R ^B include a phenyl group, a naphthyl group, a fluorenyl group, and the like, and a group in which one or all of the hydrogen atoms of the group are substituted.

Examples of the aralkyl group represented by R ^B include a benzyl group, a phenylethyl group, a phenylpropyl group, and the like, and a group in which one or all of the hydrogen atoms of the group are substituted.

Examples of the substituent of the alkyl group, the cycloalkyl group, the aryl group and the aralkyl group include a hydroxyl group, a halogen atom, an alkoxy group, a lactone group, an alkylcarbonyl group and the like.

The alkyl group represented by R ^C described above is, for example, a methyl group, an ethyl group, a propyl group or a butyl group.

The above cycloalkyl group represented by R ^C is, for example, a cyclopentyl group, a cyclohexyl group, a norbornyl group, an adamantyl group or the like.

The photodegradable base is, for example, a compound represented by the following formula Things and so on.

Among these, triphenylsulfonyl salicylate and triphenyl camphorsulfonate are preferred, and triphenyl camphorsulfonate is more preferred.

When the content of the [D] acid diffusion controlling agent is [D] acid diffusion controlling agent, it is preferably 10 parts by mass or less, more preferably 0.1% by mass based on 100 parts by mass of the [A] polymer. The mass fraction is ~7 parts by mass, more preferably 0.3 parts by mass to 5 parts by mass. When the content of the [D] acid diffusion controlling agent exceeds the above upper limit, the sensitivity of the resulting photoresist composition may be lowered. The [D] acid diffusion controlling agent may be used alone or in combination of two or more.

<[E]solvent>

The photoresist composition usually contains an [E] solvent. [E] The solvent is at least soluble or dispersible in the [A] polymer, the [B] acid generator, the other polymer [C] contained in the case, the [D] acid diffusion control agent, and any other materials described later. When it is a component, it is not specifically limited. The solvent [E] is, for example, an alcohol solvent, an ether solvent, a ketone solvent, a guanamine solvent, or an ester solvent, that is, a hydrocarbon solvent.

The alcohol solvent is, for example, methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, sec-butanol, tert-butanol, n-pentanol, i-pentanol, 2-methylbutanol, sec-pentanol, tert-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec -heptanol, 3-heptanol, n-octanol, 2-ethylhexanol, sec-octanol, n-nonanol, 2,6-dimethyl-4-heptanol, n-nonanol, sec - undecyl alcohol, trimethyl decyl alcohol, sec-tetradecanol, sec-heptadecanol, decyl alcohol, phenol, cyclohexanol, methylcyclohexanol, 3,3,5-trimethyl ring Monoalcoholic solvent such as hexanol, benzyl alcohol or diacetone alcohol; ethylene glycol, 1,2-propanediol, 1,3-butanediol, 2,4-pentanediol, 2-methyl-2,4 - pentanediol, 2,5-hexanediol, 2,4-heptanediol, 2-ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, etc. Polyol solvent; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, ethylene glycol Mono-2-ethylbutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, two Ethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene A polyol partial ether solvent such as diol monomethyl ether, dipropylene glycol monoethyl ether or dipropylene glycol monopropyl ether.

Examples of the ether solvent include a di-aliphatic ether solvent such as diethyl ether, dipropyl ether or dibutyl ether; an aromatic cyclic ether solvent such as anisole or diphenyl ether; and a cyclic ether such as tetrahydrofuran or dioxane. A solvent or the like.

The ketone solvent is, for example, acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butanone, diethyl ketone, methyl-i-butanone, methyl-n-pentanone. a chain ketone solvent such as ethyl-n-butanone, methyl-n-hexanone, di-i-butanone, trimethylketone or acetophenone; cyclopentanone, cyclohexanone, ring A cyclic ketone solvent such as heptanone, cyclooctanone or methylcyclohexanone; or a diketone solvent such as 2,4-pentanedione or acetonylacetone.

The guanamine-based solvent is, for example, N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide, acetamide, N-methylacetamide, N, a chain amide-based solvent such as N-dimethylacetamide or N-methylpropionamide; a cyclic amide solvent such as N-methylpyrrolidone or N,N-dimethylimidazolidinone .

Examples of the ester solvent include methyl acetate, ethyl acetate, n-propyl acetate, i-propyl acetate, n-butyl acetate, i-butyl acetate, sec-butyl acetate, n-pentyl acetate, and acetic acid. Sec-amyl ester, 3-methoxybutyl acetate, methyl amyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methylcyclohexane acetate Ester, n-decyl acetate, methyl ethyl acetate, ethyl acetate, ethylene glycol diacetate, acetic acid Oxyethylene triethylene glycol, ethyl propionate, n-butyl propionate, i-pentyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl lactate, ethyl lactate, lactate n- a carboxylic acid ester solvent such as butyl ester, n-amyl lactate, diethyl malonate, dimethyl phthalate or diethyl phthalate; ethylene glycol monomethyl ether, ethylene glycol single Diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl acetate, diethylene glycol mono-n-butyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol acetate a carboxylic acid ester solvent of a polyhydric alcohol partial ether such as monobutyl ether, dipropylene glycol monomethyl ether acetate or dipropylene glycol monoethyl ether; a lactone solvent such as γ-butyrolactone or γ-valerolactone; A carbonate-based solvent such as a carbonate or a propylene carbonate.

The hydrocarbon solvent is, for example, n-pentane, i-pentane, n-hexane, i-hexane, n-heptane, i-heptane, 2,2,4-trimethylpentane, n-octane An aliphatic hydrocarbon solvent such as an alkane, i-octane, cyclohexane or methylcyclohexane; benzene, toluene, xylene, trimethylbenzene, ethylbenzene, trimethylbenzene, methylethylbenzene An aromatic hydrocarbon solvent such as n-propylbenzene, i-propylbenzene, diethylbenzene, i-butylbenzene, triethylbenzene, di-i-propylbenzene or n-pentylnaphthalene .

Among these, an ester solvent or a ketone solvent is preferred, and a carboxylic acid ester solvent, a lactone solvent, a cyclic ketone solvent, more preferably a propylene glycol monomethyl ether or a γ, which is a polyol partial ether. - Butyrolactone, cyclohexanone. These solvents may be used alone or in combination of two or more.

<Other optional ingredients>

The photoresist composition may contain, in addition to the above components [A] to [E], a surfactant as an optional component, an alicyclic skeleton compound, a sensitizer, and the like. The photoresist composition may contain only one type or two or more types of the other optional components.

[Surfactant]

The surfactant has an effect of improving coatability, striation, development property, and the like of the photoresist composition. The surfactants are, for example, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octyl phenyl ether, polyoxyethylene n-nonylphenyl ether, polyethylene glycol dilaurate A nonionic surfactant such as an acid ester or a polyethylene glycol distearate, and a commercially available product such as KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, and No. 95 (the above is Kyoeisha Chemical Co., Ltd.) EF-TOP EF301, EF303, EF352 (above, TOHKEM Products), Megafac F171, F173 (above, manufactured by Dainippon Ink Chemical Industry), Fluorade FC430, FC431 (above Sumitomo 3M), AsahiGuard AG710, Surfllon S-382, same as SC-101, same SC-102, same SC-103, same SC-104, same SC-105, same SC-106 (above is Asahi Glass Industrial Co., Ltd.).

[compound containing an alicyclic skeleton]

The compound containing an alicyclic skeleton has an effect of improving dry etching resistance, pattern shape, adhesion to a substrate, and the like of the photoresist composition.

Examples of the compound having an alicyclic skeleton include adamantane derivatives such as 1-adamantanecarboxylic acid, 2-adamantone, and 1-adamantanecarboxylic acid t-butyl ester; t-butyl deoxycholate and deoxycholic acid t Deoxycholate esters such as butoxycarbonylmethyl ester and 2-ethoxyethyl deoxycholate; t-butyl lithate, t-butoxycarbonyl methyl lithate, and choline-2 Ethyl acetate such as ethoxyethyl ester; 3-[2-hydroxy-2,2-bis(trifluoromethyl)ethyl]tetracycline [4.4.0.1 ^2,5 .1 ^7,10 ]12 Alkane, 2-hydroxy-9-methoxycarbonyl-5-oxo-4-oxa-tricyclo[4.2.1.0 ^3,7 ]decane, and the like.

[sensitizer]

The sensitizer exhibits an effect of increasing the amount of acid generated by the [B] acid generator, and has an effect of improving the "apparent sensitivity" of the resist composition.

Examples of the sensitizer include carbazoles, acetophenones, benzophenones, naphthalenes, phenols, diacetyl groups, eosin, rose bengal, anthraquinones, anthraquinones, and phenothiazines.

<Modulation method of photoresist composition>

The photoresist composition can be obtained by mixing [A] polymer, [B] acid generator, [C] other polymer, [D] acid diffusion in a predetermined ratio, for example, in [E] solvent. The control body and other arbitrary components are modulated. Further, the modulated photoresist composition can be preferably used by, for example, filtering through a filter having a pore size of 20 nm. The solid content concentration of the photoresist composition is preferably from 0.1% by mass to 50% by mass, more preferably from 0.5% by mass to 30% by mass, even more preferably from 1% by mass to 15% by mass.

<Formation method of photoresist pattern>

The method for forming a photoresist pattern of the present invention has the steps of forming a photoresist film with the photoresist composition (hereinafter also referred to as "resist film formation step"), and exposing the photoresist film to light. (hereinafter also referred to as "exposure step") and a step of developing the exposed photoresist film (hereinafter also referred to as "development step"). Each step is detailed below.

[Photoresist film forming step]

In this step, a photoresist film is formed by the photoresist composition. As the substrate on which the photoresist film is formed, for example, a conventionally known substrate such as a tantalum wafer or a wafer coated with aluminum can be used. Further, an organic or inorganic antireflection film disclosed in, for example, JP-A-6-12452 or JP-A-59-93448 can be formed on the substrate.

The coating method is, for example, spin coating, cast coating, roll coating, or the like. The film thickness of the formed photoresist film is usually from 0.01 μm to 1 μm, preferably from 0.01 μm to 0.5 μm.

After coating the photoresist composition, the solvent in the coating film is volatilized by prebaking (PB) as necessary. The PB temperature can be appropriately selected depending on the composition of the photoresist composition, and is usually 30 ° C to 200 ° C, preferably 50 ° C to 150 ° C. The PB time is usually 5 seconds to 600 seconds, preferably 10 seconds to 300 seconds.

In order to prevent the influence of alkaline impurities and the like contained in the ambient atmosphere, it may be provided on the photoresist layer, for example, as disclosed in Japanese Laid-Open Patent Publication No. Hei 5-188598. Protective film shown. In addition, in order to prevent the outflow of the acid generator or the like from the photoresist layer, a protective film for liquid immersion disclosed in, for example, JP-A-2005-352384 may be provided on the photoresist film. Also, these techniques can be used in combination.

[Exposure step]

In this step, the photoresist film formed by the above-described photoresist film forming step is exposed. For example, in a desired area, a reduced-projection exposure is performed through a contour pattern mask to form an equal groove pattern. Further, the exposure can be performed twice or more using the desired pattern and mask pattern. When two or more exposures are performed, it is preferred to continuously perform exposure. In the case of multiple exposures, for example, in the desired area, the first reduction projection exposure is performed through the line and the interval pattern mask, and then the exposure portion after the first exposure is performed, and the line crossing is performed for the second time. Projection exposure. The first exposure portion and the second exposure portion are preferably orthogonal. A true circular contact hole pattern is easily formed by orthogonalizing the unexposed portion surrounded by the exposed portion. Further, the liquid immersion liquid used for the exposure is, for example, water or a fluorine-based inert liquid. The liquid immersion liquid is transparent to the exposure wavelength, and in order to minimize the deformation of the optical image projected on the film, it is preferable that the temperature coefficient of the refractive index is as small as possible, but especially the exposure light source is ArF excimer. In the case of laser light (wavelength: 193 nm), it is preferable to use water in addition to the above viewpoints in terms of ease of handling and ease of handling. When water is used, an additive which reduces the surface tension of water and increases the interfacial activity may be added only in a slight proportion. This additive is preferred to not dissolve the photoresist layer on the wafer and does not affect the optical coating beneath the lens. The water used is preferably distilled water.

Electromagnetic waves or charged particle lines used for exposure can be combined with [B] The type of the acid generator is appropriately selected, and the electromagnetic wave is, for example, ultraviolet light, far ultraviolet light, X-ray, γ-ray or the like, and the charged particle beam is, for example, an electron beam or an α-ray. Among them, far ultraviolet rays are preferable, and ArF excimer laser light, KrF excimer laser light (wavelength 248 nm), and ArF excimer laser are more preferable. The exposure conditions such as the amount of exposure are appropriately selected in accordance with the blending composition of the resist composition or the kind of the additive. In the pattern forming method of the present invention, there may be a plurality of exposure steps, and the same light source may be used for the plurality of exposures, and different light sources may be used, but the first exposure is preferably using ArF excimer laser light.

Further, post-exposure baking (PEB) after exposure is preferred. By By performing PEB, the dissociation reaction of the acid dissociable group in the photoresist composition proceeds smoothly. The PEB temperature is usually from 30 ° C to 200 ° C, preferably from 50 ° C to 170 ° C. The PEB time is usually 5 seconds to 600 seconds, preferably 10 seconds to 300 seconds.

[development step]

In this step, the photoresist film exposed by the above exposure step is developed using a developing liquid to obtain a photoresist pattern.

This step can be performed using either alkali imaging or organic solvent imaging. Generally, the exposed portion is removed by alkali development to form a positive resist pattern, and the unexposed portion is removed by organic solvent development to form a negative photoresist pattern.

When the developing solution is alkali imaging, for example, it is selected from the group consisting of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium citrate, sodium metasilicate, ammonia, ethylamine, n- Propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1 At least one of a group of basic compounds such as 8-diazabicyclo-[5.4.0]-7-undecene and 1,5-diazabicyclo-[4.3.0]-5-decene A dissolved alkaline aqueous solution or the like. The concentration of the above alkaline aqueous solution is preferably 10% by mass or less. When the concentration of the alkaline aqueous solution exceeds 10% by mass, the non-exposed portion may be dissolved in the developing liquid. An organic solvent may be added to the above alkaline aqueous solution.

In the case of the organic solvent, for example, one or two or more kinds of solvents exemplified as the [E] solvent of the photoresist composition may be used. The content of the organic solvent in the developing liquid is preferably 80% by mass or more, more preferably 90% by mass or more, and still more preferably 95% by mass or more.

A surfactant may be added in an appropriate amount in the developing solution. As the surfactant, for example, an ionic or nonionic fluorine-based and/or polyoxynoxy surfactant can be used.

The developing method is, for example, a method in which a substrate is immersed in a bath filled with a developing liquid for a certain period of time (dipping method), and a developing solution is filled on the surface of the substrate by a surface tension and is imaged at a standstill for a predetermined period of time (liquid coating method) A method of spraying a developing solution onto a surface of a substrate (spraying method), a method of applying a developing solution by applying a developing solution while scanning a developing solution at a constant speed on a substrate rotating at a constant speed, and the like (dynamic dispersion method).

After the above development, the formed photoresist pattern is preferably washed by a cleaning liquid. When the cleaning solution is used for alkali development, it is preferably water, more preferably pure water. In the case of organic solvent development, an alcohol solvent or an ester solvent is preferred, and carbon is more preferred. The number of 6 to 8 monohydric alcohol solvents is more preferably 1-hexanol, 2-hexanol, 2-heptanol or 4-methyl-2-pentanol.

The method of washing treatment is, for example, applying a cleaning solution to one A method (rotary coating method) on a substrate that rotates at a constant speed, a method (immersion method) in which a substrate is immersed in a bath filled with a cleaning liquid, a method of spraying a cleaning liquid on a surface of a substrate (spray method), and the like.

<polymer>

The polymer of the present invention is a polymer having a structural unit represented by the above formula (1). Since this polymer has the above-mentioned specific structural unit, it is suitable as a polymer component of the said photoresist composition of this invention.

In the above formula (1), R ¹ is a divalent polycyclic alicyclic hydrocarbon group having 4 to 20 carbon atoms. R ² is a monovalent monocyclic or polycyclic alicyclic hydrocarbon group having 3 to 20 carbon atoms. R ³ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

R ² in the above formula (1) is preferably a monocyclic alicyclic hydrocarbon group, more preferably a monocyclic saturated hydrocarbon group having 5 to 8 carbon atoms.

R ¹ in the above formula (1) is preferably a divalent bridged saturated hydrocarbon group having 7 to 12 carbon atoms, more preferably a tricyclo[3.3.1.1 ^3,7 ]nonane-2,2-diyl group.

<compound>

The compound of the present invention is represented by the above formula (i). Since this compound has the above specific structure, it is suitable as a monomer which provides the structural unit (I) of the said polymer.

In the above formula (i), R ¹ is a divalent polycyclic alicyclic hydrocarbon group having 4 to 20 carbon atoms. R ² is a monovalent monocyclic or polycyclic alicyclic hydrocarbon group having 3 to 20 carbon atoms. R ³ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

R ² in the above formula (i) is preferably a monocyclic alicyclic hydrocarbon group, more preferably a monocyclic saturated hydrocarbon group having 5 to 8 carbon atoms.

R ¹ in the above formula (i) is preferably a divalent bridged saturated hydrocarbon group having 7 to 12 carbon atoms, more preferably a tricyclo[3.3.1.1 ^3,7 ]nonane-2,2-diyl group.

The above R ^1, R ² and R ³ each represent a group of, for example, the above-mentioned [A] of the structural units of the polymer (I) of R ^1, R ² and R ³ are each exemplified by the same groups and the like. The polymer and the compound have been described in the [A] polymer term of the above-mentioned photoresist composition, and thus the description thereof is omitted here.

[Examples]

The invention is specifically illustrated by the following examples, but the invention is not limited by the examples. The method of measuring each physical property value is as follows.

[ ¹ H-NMR analysis and ¹³ C-NMR analysis]

¹ H-NMR analysis of the compound and ¹³ C-NMR analysis of the polymer were carried out using a nuclear magnetic resonance apparatus (JNM-ECX400, manufactured by JEOL Ltd.), and the solvent was measured to be chloroform-d.

<Synthesis of Compound (i)>

Compound (i) was synthesized according to the respective reaction charts shown below.

[Example 1] (Synthesis of 2-cyclopentyl-2-adamantyl methacrylate)

Into a 1 L reactor equipped with a stirrer and a dropping funnel, 33.0 g (0.22 mol) of 2-adamantanone and 200 mL of diethyl ether were charged. Dissolve 3.5 g of cyclopentyl magnesium 45.1 g (0.26 mol) and zinc chloride (II) in 2.6 M solution in 100 mL of diethyl ether, and drop into the reactor from the dropping funnel under nitrogen atmosphere at 20 ° C. The mixture was stirred for 16 hours while the reaction was carried out. After the reaction, the inside of the reactor was cooled to 0 ° C while a mixture of 24.3 g (0.24 mol) of triethylamine and 25.0 g (0.24 mol) of methacrylic acid chloride was dropped from the dropping funnel and stirred at 20 ° C. The reaction was carried out simultaneously for 2 hours. The obtained suspension was filtered under reduced pressure, and the obtained residue was purified to silica gel column chromatography to yield 19.7 g (yield 31%) of 2-cyclopentyl-2-adamantyl methacrylate as a white solid.

The ¹ H-NMR data of the obtained 2-cyclopentyl-2-adamantyl methacrylate are shown below.

¹ H-NMR (CDCl ₃ ) δ: 1.55-1.79 (m, 18H, CH ₂ ), 1.90 (s, 3H, CH ₃ ), 2.11-2.26 (m, 5H, CH), 5.46 (s, 1H, CH) ), 6.00 (s, 1H, CH)

[Example 2] (Synthesis of 2-cyclohexyl-2-adamantyl methacrylate)

A white solid of 2-cyclohexyl-2-adamantyl methacrylate was obtained in the same manner as in Example 1 except that 45.1 g of cyclohexylmagnesium chloride was used in place of 45.1 g of the cyclopentylmagnesium chloride in Example 1. g (yield 28%).

The ¹ H-NMR data of the obtained 2-cyclohexyl-2-adamantyl methacrylate are shown below.

¹ H-NMR (CDCl ₃ ) δ: 1.55-1.79 (m, 20H, CH ₂ ), 1.90 (s, 3H, CH ₃ ), 2.11-2.26 (m, 5H, CH), 5.46 (s, 1H, CH) ), 6.00 (s, 1H, CH)

<Synthesis of Polymers (1)>

The [A] polymer used as the base polymer and the other polymer [C] used as the water-repellent additive [C1] The monomer for synthesis of the polymer containing a fluorine atom is as follows.

[[A] Synthesis of Polymers (1)]

[Example 3]

32.5 g (40 mol%) of the above compound (M-1), (M-6) 13.9 g (10 mol%) (M-11) 53.6 g (50 mol%) was dissolved in 200 g of 2-butyl In the ketone, AIBN (4.0 g) was further added to prepare a monomer solution. A 1,000-mL three-necked flask containing 100 g of 2-butanone was substituted with nitrogen for 30 minutes, and the mixture was heated to 80 ° C while stirring, and the monomer solution prepared above was dropped using a dropping funnel over 3 hours. The polymerization reaction was carried out for 6 hours starting from the start of the dropwise polymerization as the start time of the polymerization reaction. After the end of the polymerization reaction, the polymerization reaction solution was cooled to 30 ° C or lower by water cooling. The cooled polymerization solution was poured into 2,000 g of methanol, and the precipitated white powder was obtained by filtration. The white powder obtained by filtration was washed twice with 400 g of methanol, and after filtration, it was dried at 50 ° C for 17 hours to obtain a white powdery polymer (A-1) (80 g, yield 80%). The obtained polymer (A-1) had Mw of 6,700, Mw/Mn of 1.34, and a low molecular weight content of 0.1% by mass. Further, as a result of ¹³ C-NMR analysis, the structural unit derived from the compound (M-1): the structural unit derived from the compound (M-6): the content ratio of the structural unit derived from the compound (M-11) was 39.7:8.8: 51.5 (% by mole).

[Examples 4 to 15 and Synthesis Examples 1 to 5]

Polymers (A-2) to (A-13) and (CA-1) to (CA-5) were obtained in the same manner as in Example 1 except that the types and amounts of the monomers shown in Table 1 below were used. . The Mw, Mw/Mn, yield (%) of each of the obtained polymers, the content ratio of the structural unit derived from each monomer in each polymer, and the low molecular weight content The rate is shown in Table 1.

[[C1] Synthesis of a polymer containing a fluorine atom]

[Synthesis Example 6]

7.2 g (70 mol%) of the above compound (M-2) and 2.8 g (30 mol%) of compound (M-15) and AIBN (0.46 g) were added to a 300 mL reaction flask, and 20 g of the mixture was added thereto. Butanone. Under nitrogen substitution, stirring was carried out while heating to 80 °C. The polymerization reaction was carried out for 5 hours starting with heating as the start time of the polymerization reaction. After the completion of the polymerization reaction, the solvent was distilled off so that the ratio of the amount of the solvent/the amount of the monomer to be added was 0.5, and the residue was poured into 150 g of a mixed solvent of methanol/distilled water = 2/1 (mass ratio). The resulting viscous solid was obtained, so only the white turbid supernatant was removed using a tilting method. Then, 20 g of a mixed solvent of methanol/distilled water = 4/1 (mass ratio) was added to the residue, and the viscous solid was washed, and the supernatant liquid was again removed only in an inclined manner. The viscous solid was washed twice in the same manner. The obtained viscous solid was dried at 50 ° C for 17 hours to obtain a colorless transparent solid polymer (C-1) (6.7 g, yield 67%). This polymer (C-1) had a Mw of 9,400 and a Mw/Mn of 1.42. Further, as a result of ¹³ C-NMR analysis, the structural unit derived from the compound (M-2): the content ratio of each of the structural units derived from the compound (M-15) was 69.2:30.8 (mol%).

[Synthesis Example 7]

37.41 g (40 mol%) of the following compound (M-3) and 62.59 g (60 mol%) of the following compound (M-16) were dissolved in 100 g of 2-butanone, and AIBN (4.79 g) was dissolved again. a monomer solution. A 1,000-mL three-necked flask containing 100 g of 2-butanone was subjected to nitrogen substitution for 30 minutes, and after nitrogen substitution, the reaction vessel was stirred and heated to 80 ° C, and the monomer solution prepared above was used in a dropping funnel for 3 hours. dropping. The polymerization reaction was carried out for 6 hours starting from the start of the dropwise addition as the polymerization start time. After the completion of the polymerization reaction, 150 g of 2-butanone was removed from the polymerization reaction solution under reduced pressure. After cooling to 30 ° C or lower, the polymerization reaction solution was poured into a mixed solvent of 900 g of methanol and 100 g of ultrapure water, and the precipitated white powder was obtained by filtration. The white powder obtained by filtration was dispersed in 100 g of methanol to form a slurry, and after washing, the operation was repeated twice by filtration. The obtained white powder was vacuum dried at 50 ° C for 17 hours to obtain a polymer (C-2) (78 g, yield 78%). This polymer (C-2) had a Mw of 6,900 and Mw/Mn = 1.41. Further, as a result of ¹³ C-NMR analysis, the structural unit derived from the compound (M-3): the content ratio of the structural unit derived from the compound (M-16) was 40.8:59.2 (mol%).

[Synthesis Examples 8 to 10]

Polymers (C-3) to (C-5) were obtained in the same manner as in Synthesis Example 7 except that the monomers of the type and amount used in Table 2 below were used. The content ratio of Mw, Mw/Mn, yield (%) of each of the obtained polymers and the structural unit of each monomer in each polymer is shown in Table 2, for example.

<Modulation of Photoresist Composition>

The [B] acid generator, the [D] acid diffusion control agent, and the [E] solvent used for preparing the photoresist composition of each of the examples and the comparative examples are as follows.

[[B]acid generator]

B-1: triphenylphosphorylidene-1-oxycarbonyldifluoromethanesulfonate (compound represented by the following formula (B-1))

B-2: triphenylphosphonium 2-(adamantan-1-yl)-1,1-difluoroethane-1-sulfonate (compound represented by the following formula (B-2))

B-3: triphenylsulfonium 6-(adamantan-1-ylcarbonyloxy)-1,1,2,2-tetrafluorohexane-1-sulfonate (formula (B-3) below) Compound)

[[D] Acid Diffusion Control Agent]

D-1: 2,6-diisopropylaniline (a compound represented by the following formula (D-1))

D-2: t-pentyl-4-hydroxy-1-piperidinecarboxylate (compound represented by the following formula (D-2))

D-3: triphenyl camphorsulfonate (compound represented by the following formula (D-3))

[[E]solvent]

E-1: propylene glycol monomethyl ether acetate

E-2: cyclohexanone

E-3: γ-butyrolactone

[Example 16]

100 parts by mass of (A-1) of the [A] polymer, (B-1) of 12 parts by mass of the [B] acid generator, and (C-1) of the polymer of the [C1] fluorine atom. 3 parts by mass, (D-1) 1 part by mass as the [D] acid diffusion controlling agent, and 1,980 parts by mass of propylene glycol monomethyl ether (E-1) as a solvent, and cyclohexanone (E-2) 848 mass The mixture and 200 parts by mass of γ-butyrolactone (E-3) were mixed to form a homogeneous solution. Then, this homogeneous solution was filtered using a membrane filter having a pore size of 200 nm to prepare the photoresist composition of Example 12.

[Examples 17 to 28 and Comparative Examples 1 to 5]

Each of the photoresist compositions was prepared in the same manner as in Example 16 except that the components of the types and amounts shown in Table 3 below were used.

<evaluation>

A photoresist pattern was formed according to the following method, and the LWR performance and EL performance of the photoresist composition were evaluated. The evaluation results are shown in Table 3.

[Formation of photoresist pattern]

A lower-layer anti-reflection film (ARC66, manufactured by Nissan Chemical Co., Ltd.) having a film thickness of 105 nm was formed on the surface of a 12-inch wafer as a substrate. On each of the lower reflection preventing films, each of the photoresist compositions was applied by a spin coating method, and PB was applied at 100 ° C for 60 seconds on a hot plate to form a photoresist film having a film thickness of 90 nm. Next, the photoresist film was formed using an ArF excimer laser immersion exposure apparatus (NSR S610C, manufactured by NIKON), and a pattern of 40 nm line and 80 nm pitch was formed by the conditions of NA = 1.3, ratio=0.800, and Dipole. The reticle pattern is used for exposure. After the exposure, exposure baking (PEB) was performed at 90 ° C for 60 seconds. Of course Thereafter, development was carried out by using a 2.38 mass% aqueous solution of tetramethylammonium hydroxide (TMAH) as a developing solution, washing with water, and drying to form a positive resist pattern. At this time, the portion of the mask pattern formed by the pattern formation is exposed, and the line having a line width of 40 nm and the pitch pattern (1L/1S) form an exposure amount of 1:1 line width as the optimum exposure amount. (Eop).

[LWR performance]

Using a scanning electron microscope (CG4000, manufactured by Hitachi High-Tech Co., Ltd.), a line having a line width of 40 nm and a pitch pattern formed by the above Eop was observed at an arbitrary ten points from the upper portion of the pattern, and the line width of the pattern was measured. The 3σ value as the distribution state was obtained from the measured value of the line width as the LWR performance (nm). The smaller the value of the LWR performance, the higher the line width accuracy of the pattern, which improves the yield of the device.

[EL performance]

In the range including the exposure amount of the above Eop, the exposure amount was changed by 1 mJ, and a resist pattern was formed, and the respective line widths were measured using the above-described scanning electron microscope. From the relationship between the obtained line width and the exposure amount, the exposure amount E (44) having a line width of 44 nm and the exposure amount E (36) having a line width of 36 nm were obtained, and EL = (E (36) - E (44). )) The formula of ×100/(optimum exposure amount) was used to calculate the EL performance (%). The larger the value, the smaller the variation in the size of the pattern obtained when the exposure amount is deviated, and the yield at the time of device production can be improved.

[Example 29 and Comparative Examples 6 to 8]

Each of the photoresist compositions was prepared in the same manner as in Example 16 except that the components of the types and amounts shown in Table 4 below were used.

<evaluation>

A photoresist pattern was formed according to the following method, and the LWR properties and EL properties of the photoresist composition were evaluated in accordance with the above evaluation method. The evaluation results are shown in Table 4.

[Formation of photoresist pattern]

A lower-layer anti-reflection film (ARC66, manufactured by Nissan Chemical Co., Ltd.) having a film thickness of 105 nm was formed on the surface of a 12-inch wafer as a substrate. On each of the lower reflection preventing films, each of the photoresist compositions was applied by a spin coating method, and PB was applied at 100 ° C for 60 seconds on a hot plate to form a photoresist film having a film thickness of 90 nm. Next, the photoresist film was formed using an ArF excimer laser immersion exposure apparatus (NSR S610C, manufactured by NIKON), and a pattern of 40 nm line and 80 nm pitch was formed by the conditions of NA = 1.3, ratio=0.800, and Dipole. The reticle pattern is used for exposure. After the exposure, exposure baking (PEB) was performed at 90 ° C for 60 seconds. Then, development was carried out using butyl acetate as a developing solution, washing with 4-methyl-2-pentanol, and drying to form a negative resist pattern. At this time, the portion of the mask pattern formed by the pattern formation is exposed, and the line having a line width of 40 nm and the pitch pattern (1L/1S) form an exposure amount of 1:1 line width as the optimum exposure amount. (Eop).

As is clear from the results shown in Tables 3 and 4, the photoresist composition of the examples was excellent in LWR performance and EL performance.

<Synthesis of Polymers (2)>

The [A] polymer and [C1] a fluorine atom-containing polymer used as a water-repellent additive were synthesized as follows.

[[A] Synthesis of Polymers (2)]

[Example 30]

The compound (M-6) 7.02 g (20 mol%) and the above compound (M-16) 22.98 g (80 mol%) were dissolved in 30 g of 2-butanone, and AIBN (1.00 g) was dissolved again. Monomer solution. A 1,000-mL three-necked flask containing 15 g of 2-butanone was subjected to nitrogen substitution for 30 minutes, and after nitrogen substitution, the reaction vessel was stirred and heated to 80 ° C, and the monomer solution prepared above was used in a dropping funnel for 3 hours. dropping. The polymerization reaction was carried out for 6 hours starting from the start of the dropwise addition as the polymerization start time. After the completion of the polymerization reaction, 30 g of 2-butanone was removed from the polymerization reaction solution under reduced pressure. After cooling to 30 ° C or lower, the polymerization reaction solution was poured into a mixed solvent of 900 g of methanol and 100 g of ultrapure water, and the precipitated white powder was obtained by filtration. The white powder obtained by filtration was dispersed in 100 g of methanol to form a slurry, and after washing, the operation was repeated twice by filtration. The obtained white powder was vacuum dried at 50 ° C for 17 hours to obtain a polymer (A-14) (yield 62%). The polymer (A-14) had a Mw of 5,600 and Mw/Mn = 1.55. Further, as a result of ¹³ C-NMR analysis, the structural unit derived from the compound (M-6): the content ratio of the structural unit derived from the compound (M-16) was 15.2:84.8 (mol%).

[Examples 31 to 33]

Polymers (A-15) to (A-17) were obtained in the same manner as in Example 30 except that the monomers of the type and amount used in Table 5 below were used.

[[C1] Synthesis of a polymer containing a fluorine atom (2)]

[Synthesis Example 10]

The polymer (C-6) was obtained in the same manner as in Example 30 except that the monomer of the type and amount used in the following Table 5 was used.

The content ratios of Mw, Mw/Mn, yield (%) of each of the polymers obtained above and the structural unit of each monomer in each polymer are shown in Table 5, for example.

<Modulation of Photoresist Composition (2)>

[Example 34]

100 parts by mass of (A-1) of the [A] polymer and 5 parts by mass of (A-14), and 12 parts by mass of (B-1) as the [B] acid generator, as [D] acid diffusion control 1 part by mass of the agent (D-1), and (E-1) 1,980 parts by mass, (E-2) 848 parts by mass, and (E-3) 200 parts by mass of the solvent were mixed to form a homogeneous solution. Then, this homogeneous solution was filtered using a membrane filter having a pore size of 200 nm to prepare the photoresist composition of Example 34.

[Examples 35 to 38]

Each photoresist composition was prepared in the same manner as in Example 34 except that each component of the type and amount shown in Table 6 below was used.

<evaluation>

A photoresist pattern was formed according to the following method, and the development defect suppressing property of the photoresist composition was evaluated in accordance with the following evaluation method. The evaluation results are shown in Table 6.

A photoresist composition was applied to the surface of a 12-inch wafer on which a lower-layer anti-reflection film (ARC66, manufactured by Nissan Chemical Co., Ltd.) was formed, and a photoresist film having a film thickness of 75 nm was formed. Next, an ArF excimer laser immersion exposure apparatus (manufactured by NSR S610C, manufactured by NIKON) was used for this photoresist film, and exposure was performed in a mask pattern by the conditions of NA = 1.3, ratio=0.812, and Crosspole. After the exposure, baking was performed at 105 ° C for 60 seconds. Then, development was carried out by a 2.38 mass% aqueous solution of tetramethylammonium hydroxide, washed with water, and dried to form a positive resist pattern. At this time, the exposure of the line and the pitch of 55 nm wide is formed as the best. Exposure. With this optimum exposure amount, a line and a pitch of 55 nm in line width are formed on the wafer as a wafer for defect inspection. Further, a scanning electron microscope (S-9380, manufactured by Hitachi High-Technologies) was used for the length measurement. Then, the number of defects on the wafer for defect inspection was measured using KLA2810 manufactured by KLA-Tencor. The measured defects are classified into judged from the photoresist and from the external foreign matter. After the classification, it was judged that the total number of the photoresistors (the number of defects) was 100/wafer or less, and the evaluation was "A" (good), and when it was more than 100/wafer, the evaluation was "B" (bad).

As is clear from the results shown in Table 6, the photoresist composition containing the [A] polymer as the water-repellent additive is excellent in development defect suppressing property.

[Industrial availability]

According to the method for forming a photoresist composition and a photoresist pattern of the present invention, a wide EL can be secured, and a photoresist pattern excellent in LWR can be formed. Further, when the photoresist composition containing the [A] polymer as a water-repellent additive is used, occurrence of development defects in the photoresist pattern can be suppressed. The polymer of the present invention is suitably used as a polymer component of the photoresist composition. The compound of the present invention is suitably used as a raw material monomer of the polymer. Therefore, the photoresist composition, the method for forming a photoresist pattern, the polymer, and the compound of the present invention are suitable for use in semiconductor devices which are required to be more refined in the future, have higher precision in pattern formation, and have higher yield.

Claims (20)

A photoresist composition characterized by containing a polymer having an structural unit represented by the following formula (1) and an acid generator. (In the formula (1), R ¹ is a divalent polycyclic alicyclic hydrocarbon group having 4 to 20 carbon atoms, and R ² is a monovalent monocyclic or polycyclic alicyclic hydrocarbon group having 3 to 20 carbon atoms, R ³ Is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group). The photoresist composition according to claim 1, wherein R ² in the above formula (1) is a monocyclic alicyclic hydrocarbon group. The photoresist composition according to claim 2, wherein the monocyclic alicyclic hydrocarbon group is a saturated hydrocarbon group having 5 to 8 carbon atoms. The photoresist composition according to claim 1, wherein R ¹ in the above formula (1) is a bridged saturated hydrocarbon group having 7 to 12 carbon atoms. The photoresist composition of claim 4, wherein the bridged saturated hydrocarbon group is a tricyclo[3.3.1.1 ^3,7 ]nonane-2,2-diyl group. The photoresist composition of claim 1, wherein the [A] polymer further comprises a structural unit having at least one structure selected from the group consisting of a lactone structure, a cyclic carbonate structure, and a sultone structure. . For example, the photoresist composition of claim 1 of the patent scope, wherein [A] The compound further contains a fluorine atom. The photoresist composition according to claim 1, wherein the [A] polymer further contains a structural unit represented by the following formula (2). (In the formula (2), R ⁴ is a monovalent chain hydrocarbon group having 1 to 10 carbon atoms, and R ⁵ and R ⁶ are each independently a monovalent chain hydrocarbon group having 1 to 10 carbon atoms or 1 to 3 carbon atoms. a valence alicyclic hydrocarbon group, or R ⁵ and R ^{6 are} bonded to each other and a carbon atom to which they are bonded, together form a divalent cyclic group having 3 to 20 carbon atoms, and R ⁷ is a hydrogen atom, a fluorine atom or a methyl group. Or trifluoromethyl). The photo-resist composition of claim 1, wherein the content ratio of the structural unit represented by the above formula (1) is 5 mol% or more and 50 mol% with respect to the total structural unit constituting the [A] polymer. the following. A method for forming a photoresist pattern, characterized by the steps of: exposing the photoresist film by a step of forming a photoresist film according to the photoresist composition of claim 1 and after exposing The photoresist film is subjected to a development step. A polymer characterized by having a structural unit represented by the following formula (1), (In the formula (1), R ¹ is a divalent polycyclic alicyclic hydrocarbon group having 4 to 20 carbon atoms, and R ² is a monovalent monocyclic or polycyclic alicyclic hydrocarbon group having 3 to 20 carbon atoms, R ³ Is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group). The polymer of claim 11, wherein R ² in the above formula (1) is a monocyclic alicyclic hydrocarbon group. The polymer of claim 12, wherein the monocyclic alicyclic hydrocarbon group is a saturated hydrocarbon group having 5 to 8 carbon atoms. The polymer of claim 11, wherein R ¹ in the above formula (1) is a bridged saturated hydrocarbon group having 7 to 12 carbon atoms. The polymer of claim 14, wherein the bridged saturated hydrocarbon group is a tricyclo[3.3.1.1 ^3,7 ]decane-2,2-diyl group. a compound characterized by the following formula (i), (In the formula (i), R ¹ is a divalent polycyclic alicyclic hydrocarbon group having 4 to 20 carbon atoms, and R ² is a monovalent monocyclic or polycyclic alicyclic hydrocarbon group having 3 to 20 carbon atoms, R ³ Is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group). The compound of claim 16, wherein R ² in the above formula (i) is a monocyclic alicyclic hydrocarbon group. The compound of claim 17, wherein the monocyclic alicyclic hydrocarbon group is a saturated hydrocarbon group having 5 to 8 carbon atoms. A compound according to claim 16, wherein R ¹ in the above formula (i) is a bridged saturated hydrocarbon group having 7 to 12 carbon atoms. A compound according to claim 19, wherein the bridged saturated hydrocarbon group is a tricyclo[3.3.1.1 ^3,7 ]nonane-2,2-diyl group.