WO2006064626A1

WO2006064626A1 - Polymer compound, positive resist composition and method for forming resist pattern

Info

Publication number: WO2006064626A1
Application number: PCT/JP2005/021146
Authority: WO
Inventors: Yohei Kinoshita; Yuko Kurimoto; Takeshi Iwai
Original assignee: Tokyo Ohka Kogyo Co., Ltd.
Priority date: 2004-12-14
Filing date: 2005-11-17
Publication date: 2006-06-22
Also published as: JP4738803B2; JP2006169319A

Abstract

Disclosed is a positive resist composition containing a polymer compound which contains at least two constitutional units (a1) selected from the group consisting of constitutional units represented by the general formula (a1-01) below and constitutional units represented by the general formula (a1-02) below. (a1-01) (a1-02) (In the formulae, Y represents an alicyclic group; n represents 0 or an integer of 1-3; m represents 0 or 1; R independently represents a hydrogen atom, a lower alkyl group having 1-5 carbon atoms, a fluorine atom or a fluorinated lower alkyl group having 1-5 carbon atoms; and R1 and R2 independently represent a hydrogen atom or a lower alkyl group having 1-5 carbon atoms.)

Description

Specification

Polymer compound, positive resist composition, and resist pattern forming method

The present invention relates to a polymer compound, a positive resist composition, and a resist pattern forming method.

This application claims priority based on Japanese Patent Application No. 2004-361399 filed with the Japan Patent Office on December 14, 2004, the contents of which are incorporated herein by reference.

Background art

In recent years, in the manufacture of semiconductor elements and liquid crystal display elements, miniaturization has rapidly progressed due to advances in lithography technology. As a technique for miniaturization, the wavelength of an exposure light source is generally shortened. Specifically, ultraviolet rays typified by g-line and i-line have been used in the past, but now KrF excimer laser (248nm) is the center of mass production, and ArF excimer laser (193nm) is mass-produced. It has begun to be introduced. F excimer laser

2

Research is also being carried out on lithography technology using 157 nm, EUV (extreme ultraviolet light), EB (electron beam), etc. as a light source (radiation source).

Such a resist for a short wavelength light source is required to have high resolution capable of reproducing a pattern with a fine dimension and high sensitivity to such a short wavelength light source. As one of the resists satisfying such conditions, a chemically amplified resist containing a base resin and an acid generator (hereinafter referred to as PAG) that generates an acid upon exposure is known. There are two types of dies: a positive type in which the alkali solubility in the exposed area increases and a negative type in which the alkali solubility in the exposed area decreases.

[0003] Until now, as a base resin for chemically amplified resists, the transparency to KrF excimer laser (248 nm) is high, and the hydroxyl group of polyhydroxystyrene (PHS) has been protected with an acid dissociable, dissolution inhibiting group.榭脂 (PHS 系榭脂) has been used. However, since PHS resin has an aromatic ring such as a benzene ring, the transparency to light having a wavelength shorter than 248 nm, for example, 193 nm, is not sufficient. For this reason, chemically amplified resists that use PHS-based resin as the base resin component have low resolution, for example, in processes using 193 nm light. There are drawbacks.

Therefore, as the base resin of the resist currently used in ArF excimer laser lithography etc., it has excellent transparency at around 193 nm, so the structural unit derived from (meth) acrylate ester chain is the main chain. In particular, as shown in Patent Document 1 below, (meth) acrylic acid tertiary ester compound is used as an acid dissociable, dissolution inhibiting group. In general, structural units are also used that are also capable of inducing isotopic forces, such as 2-alkyl-2-adamantyl (meth) acrylate. This constituent unit is known to have a high elimination energy of the acid dissociable, dissolution inhibiting group.

Patent Document 1: Japanese Patent No. 2881969

Disclosure of the invention

Problems to be solved by the invention

[0004] By the way, in recent years, as a resin having an acid dissociable, dissolution inhibiting group used in ArF excimer laser lithography and the like, the elimination energy of the acid dissociable, dissolution inhibiting group is higher than that of the tertiary ester compound. Low, a resin having a structural unit in which a hydrogen atom of (meth) acrylic acid is substituted with an acetal group (alkoxyalkyl group) has begun to attract attention. The ability to form a fine pattern by using a resin having the structural unit has a problem of pattern collapse of the resist pattern. Moreover, it is difficult to suppress the turnover while maintaining the resist pattern shape in good condition.

[0005] The present invention has been made in view of the above circumstances, and is a high molecular compound capable of forming a resist pattern having high resolution, suppressed pattern collapse, and good shape, and the high molecular compound. It is an object of the present invention to provide a positive resist composition containing the above and a resist pattern forming method.

Means for solving the problem

In order to achieve the above object, the present invention employs the following configuration.

That is, in the first aspect of the present invention, a structural unit represented by the following general formula (al-01) and a group force represented by the structural unit force represented by the following general formula (al-02) are selected. It is a polymer compound having a structural unit (al) of a kind.

[Chemical 1]

(a 1-0 1) (a 1-0 2)

[In the above formula, Y represents an aliphatic cyclic group; η represents 0 or an integer of 1 to 3; m represents 0 or 1; and R independently represents a hydrogen atom or a carbon number of 1 to 5] Lower alkyl group, fluorine source

R ² each independently represents a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms. ]

[0007] The second aspect of the present invention is a positive resist composition comprising a resin component (A) whose alkali solubility is increased by the action of an acid, and an acid generator component (B) which generates an acid upon exposure. Wherein the component (A) is selected from the structural unit represented by the general formula (al-01) and the structural unit force represented by the general formula (al-02). A positive resist composition having various constituent units (al).

[0008] The third aspect of the present invention includes a step of forming a resist film on a substrate using the positive resist composition of the second aspect of the present invention, a step of exposing the resist film, And a step of developing a resist film to form a resist pattern.

The invention's effect

[0009] According to the present invention, the resolution is high, the pattern collapse is suppressed, and the shape is good. Provided are a polymer compound capable of forming a resist pattern, a positive resist composition containing the polymer compound, and a resist pattern forming method.

BEST MODE FOR CARRYING OUT THE INVENTION

[0010] The "structural unit" in the claims and the specification means a monomer unit (monomer unit) constituting the polymer compound.

The “structural unit derived from acrylic acid power” in the claims and the specification means a structural unit constituted by cleavage of an ethylenic double bond of acrylic acid. “Structural unit induced by acrylate ester power” in the claims and the specification means a structural unit formed by cleavage of an ethylenic double bond of an acrylate ester.

“Acrylic ester force-derived structural unit” includes a concept in which the α-position hydrogen atom is substituted with another substituent such as a halogen atom, an alkyl group, or a halogenialkyl group.

In addition, the “structural unit that also induces acrylic acid power” is a structural unit in which a hydrogen atom bonded to a carbon atom at the α-position is substituted with another substituent such as a halogen atom, an alkyl group, a halogenated alkyl group, _The concept includes a structural unit derived from an acrylate ester in which a hydrogen atom is bonded to a carbon atom at the _α- position.

In the “structural unit from which acrylic acid power is also induced” and “structural unit from which acrylic acid ester power is also derived”, the term “hi-position (α-position carbon atom)” means that the carboxy group is a group unless otherwise specified. It is a carbon atom that is bonded.

Further, the “alkyl group” includes a linear, cyclic or branched alkyl group unless otherwise specified.

[0011] <Polymer compound (Α)> [Structural unit (al)]

The polymer compound of the present invention comprises a structural unit represented by the general formula (al-01) and a group force represented by the structural unit represented by the general formula (al-02). Has unit (al).

The structural unit (al) is a structural unit derived from carboxylic acid, and is bonded to an acetal group at the oxygen atom at the terminal of a carbo-oxy group (—C (O) —O—) derived from a carboxy group. ( Alkoxyalkyl group) type acid dissociable, dissolution inhibiting group [-c (R'R ² ) — O— (CH)-

2 n

Y] has a bonded structure. Therefore, when an acid acts, a bond is cut between the acid dissociable, dissolution inhibiting group and the terminal oxygen atom.

Therefore, the polymer compound (Α) of the present invention is insoluble in alkali before the acid is allowed to act, and when the acid is allowed to act, the above-described acid dissociable, dissolution inhibiting group is dissociated, thereby polymerizing. The whole thing (Α) can change to alkali-soluble.

The deprotection energy of the acetal group (alkoxyalkyl group) type acid dissociable dissolution inhibiting group is lower than that of the tertiary ester type acid dissociable dissolution inhibiting group, so the structural unit (al) is Even if the acid strength is weak, there is an advantage that the acid dissociable, dissolution inhibiting group can be eliminated to increase the alkali solubility, thereby resolving a fine pattern.

In addition, since the deprotection energy is low, the acid strength as a catalyst can be weakened, so that there is an advantage that the selection range of the acid generator can be expanded.

Specifically, for example, a diazomethane acid generator, an acid generator having a camphor sulfonate ion in the cation portion, an oxime sulfonate acid generator, or the like can also be dissociated.

In formulas (al-01) and (al-02), R is a hydrogen atom, a lower alkyl group having 1 to 5 carbon atoms, a fluorine atom or a fluorinated lower alkyl group having 1 to 5 carbon atoms. is there. The fluorinated lower alkyl group is a group in which part or all of the hydrogen atoms of the alkyl group are substituted with fluorine atoms, and any of them may be used, but it is preferable that all are fluorinated.

Preferred examples of the lower alkyl group as R include a methyl group, an ethyl group, a propyl group, an isopropyl group, an _n -butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. It is done. Industrially, a methyl group is preferable. The fluorinated lower alkyl group having 1 to 5 carbon atoms is preferably a trifluoromethyl group such as a trifluoromethyl group, a hexafluoroethyl group, a heptafluoropropyl group, or a nonafluorobutyl group. More preferred ,.

Each R ² is independently a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms; is there.

In the above, R ² is preferably at least one hydrogen atom, more preferably a hydrogen atom. n is preferably 0 or 1.

[0013] Y is an aliphatic cyclic group, which may or may not have a substituent on the ring skeleton.

Here, “aliphatic” in the claims and the specification is a relative concept to aromatics, and is defined to mean a group, a compound, or the like that does not have aromaticity. The “aliphatic cyclic group” means a monocyclic group or polycyclic group having no aromaticity. Except for the substituents of the “aliphatic cyclic group” in the present invention, the basic ring structure is not limited to a group consisting of carbon and hydrogen (hydrocarbon group). Preferably there is. The “hydrocarbon group” may be either saturated or unsaturated, but is usually preferably saturated. A polycyclic group is preferred.

Specific examples of such an aliphatic cyclic group include, for example, a group obtained by removing one or more hydrogen atoms from a polycycloalkane such as monocycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane. It can be illustrated.

Specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. It is done. Among these, Y is preferably an adamantane that removes one or more hydrogen atoms! Or a group (which may have a substituent)! / ヽ

When the aliphatic cyclic group as Y has a substituent on the ring skeleton, the substituent is preferably a polar group, particularly in order to suppress pattern collapse. Specific examples of the polar group include a hydroxyl group, a carboxy group, a cyano group, and an oxygen atom (= o). Of these, an oxygen atom (= o) is preferable.

[0014] Specific examples of the structural unit represented by the general formula (al-01) are shown below.

[Chemical 2]

Tsuyoshi [STOO]

(S-lO-ie)

-LB)

[0016] Specific examples of the structural unit represented by the general formula (a 1-02) are shown below.

[0017] [4]

]

Set 00) ((丄 4al02 (al02aT02 (al02 ---

( _a1 -02-19) (a! -02-20) (a1-02-21) (a1 -02-22) The structural unit (al) is represented by the general formula (al-01). Unit and unit power represented by the above general formula (al-02) Group force is selected.

It is preferable from the viewpoint of resolution that at least the structural unit represented by the general formula (al-01) is included in the two or more structural units used as (al). In addition, it is preferable that 50% or more is contained in the structural unit force (al) represented by the general formula (al-01), and that 80% or more is more preferable. 100% Most preferably.

(al) may be two or more different structural units selected from the medium power of the structural unit represented by the general formula (al — 01)! /. [0021] (al) is a structural unit in which Y is an aliphatic cyclic group having a substituent on its ring skeleton, and Υ does not have a substituent on its ring skeleton! / Both of structural units which are aliphatic cyclic groups may be included.

As (al), among the structural unit represented by the general formula (al-01) and the structural unit represented by (al-02), Y is an aliphatic cyclic group having a substituent on its ring skeleton. And one or more of the structural units (hereinafter sometimes referred to as “having a substituent”), and Y is a structural unit (hereinafter referred to as an aliphatic cyclic group) that does not have a substituent on the ring skeleton. From the viewpoint of the effect of the present invention, it is preferable to use one or more of “no substituent” t (sometimes).

In particular, at least one structural unit selected from the formulas (al-01-01) to (al-01-01) and the formulas (al-02-1) to (al-02-20) and Formula (al 01-15) ~ (al

— 01— 16) and the above formulas (al-02-02) to (al-02-02) It is preferable to use at least one structural unit of which the force is also selected. 7) to (& 1 01—14) at least one structural unit for which force is also selected and the formula (al—01—15) to (al

— 01— 16) is more preferably used in combination with at least one structural unit selected from the formulas (al—01—9) to (al—01—10) and (al—01—13) to ( al—01—14) The combination of at least one structural unit selected from force and at least one structural unit selected from the above formulas (al 01-15) to (al 01-16) is most preferable. I like it.

In the case of using both “with substituent” and “without substituent” as the (al) unit, the ratio of both in the entire (al) unit is the molar ratio of “with substituent” to “without substituent”. The range of 9: 1 to 1: 9 is preferred, and the range of 8: 2 to 2: 8 is particularly preferred. The range of 6: 4 to 4: 6 is preferred. By setting it as the said range, it becomes the thing excellent in the effect of this invention.

[0022] Polymer Compound Contact) in the proportion of the structural unit (al) is based on all the structural units that constitute the polymer compound (A), 10 to 80 Monore ^_0/0 force S Preferably, 20-70 Monore ⁰ / ₀ force S is more preferable, and 25 to 50 mol% is more preferable. By setting it to the lower limit value or more, a good resist pattern can be obtained when the resist composition is used, and by setting the upper limit value or less, it is possible to obtain a tolerance with other structural units.

[0023] [Structural unit (a2)]

In addition to the structural unit (al), the polymer compound (A) is a monocyclic or polycyclic compound containing latathone. It is preferable to have the structural unit (a2) derived from the acrylate ester group having a group.The lathetone-containing monocyclic or polycyclic group of the structural unit (a2) is used to form a polymer film (A) for forming a resist film. When used, it is effective in increasing the adhesion of the resist film to the substrate and increasing the hydrophilicity with the developer.

Here, the ratatone-containing monocyclic or polycyclic group refers to a cyclic group containing one ring (lataton ring) containing an O C (O) structure. The rataton ring is counted as the first ring, and when only the rataton ring is present, it is called a monocyclic group, and when it has another ring structure, it is called a polycyclic group regardless of the structure.

As the structural unit (a2), any unit can be used without any particular limitation as long as it has both such a structure of laton (10—C (O) —) and a cyclic group. .

Specifically, examples of the latatatone-containing monocyclic group include groups in which y-peptidyl latatone force hydrogen atom is removed. In addition, examples of the latathone-containing polycyclic group include groups in which bicycloalkane, tricycloalkane, and tetracycloalkane having a latathone ring have one hydrogen atom removed. In particular, a group obtained by removing one hydrogen atom from a latathone-containing tricycloalkane having the following structural formula is advantageous in that it is easily available industrially.

[0025] [Chemical 7]

[0026] More specifically, examples of the structural unit (a2) include structural units represented by the following general formulas (a2-1) to (a2-5).

[0027] [Chemical 8]

02-5)

(a2-4)

[Wherein, R is the same as defined above, R ′ is a hydrogen atom, a lower alkyl group, or an alkoxy group having 1 to 5 carbon atoms, and m is an integer of 0 or 1.] ]

[0029] In the general formulas (a2-1) to (a2-5), the lower alkyl group for R 'is the structural unit described above.

The same as the lower alkyl group for R in (al).

In general formulas (a2-1) to (a2-5), R ′ is preferably a hydrogen atom in view of industrial availability.

[0030] Specific structural units of the general formulas (a2-1) to (a2-5) are exemplified.

[0031] [Chemical 9]

(a2-1-1) (a2 small 2)

(a2-1-3)

(a2-1-4) (a2-1-5)

[0032] [Chemical 10]

[0033] [Chemical 11]

]] [[120034

(a2 ~ '11)

[0036] As the structural unit (a2), it is preferable to use at least one selected from the general formulas (a2—l) to (a2-5), and from the general formulas (a2-1) to (a2-3) It is more preferable to use one or more selected. Among them, chemical formulas (a2-1-1), (a2-1-2), (a2-2-1), (a2-2-2), (a2-3-1), (a2-3-2) It is preferable to use one or more selected from (a2-3-9) and (a2-3-10) force.

[0037] In the polymer compound (A), as the structural unit (a2), one type may be used alone, or two or more types may be used in combination.

The proportion of the structural unit (a2) in the polymer compound (A) is preferably 10 to 80 mol%, preferably 10 to 50 mol%, based on the total of all the structural units constituting the polymer compound (A). More preferably, it is 25 to 50 mol%. By setting it to the lower limit value or more, the effect of including the structural unit (a2) is sufficiently obtained, and by setting it to the upper limit value or less, it is possible to balance with other structural units.

In the present invention, the polymer compound (A) is a copolymer having the structural units (al) and (a2). It is preferable that it is a coalescence because the effect of the present invention is excellent.

[0038] [Structural unit (a3)]

The polymer compound (A) further contains a non-acid-dissociable polar group-containing aliphatic hydrocarbon group in addition to the structural unit (al) or in addition to the structural units (al) and (a2). Acrylic ester force may also be derived from a structural unit ( _a 3). “Non-acid-dissociable” means that the “polar group-containing aliphatic hydrocarbon group” is not eliminated by the action of an acid, that is, has no property as an acid-dissociable, dissolution inhibiting group.

By having the structural unit (a3), the hydrophilicity of the component (A) is increased, the affinity with the developer is increased, the alkali solubility in the exposed area is improved, and the resolution is improved.

[0039] Examples of the polar group in the "polar group-containing aliphatic hydrocarbon group" include a hydroxyl group, a cyano group, a force group, a "hydroxyalkyl group in which a part of the hydrogen atoms of the alkyl group are substituted with fluorine atoms" and the like. Particularly preferred are hydroxyl groups.

Examples of the aliphatic hydrocarbon group in the “polar group-containing aliphatic hydrocarbon group” include a linear or branched hydrocarbon group having 1 to 10 carbon atoms (preferably an alkylene group), and a polycyclic aliphatic group. And hydrocarbon groups (polycyclic groups). As the polycyclic group, for example, a resin for a resist composition for ArF excimer laser can be appropriately selected and used from among many proposed ones.

As the structural unit (a3), an aliphatic polycyclic group containing, in particular, a hydroxyl group, a cyano group, a carboxy group, or a “hydroxyalkyl group in which part of the hydrogen atoms of the alkyl group is substituted with fluorine atoms” And a structural unit derived from an acrylate ester is more preferred. Examples of the polycyclic group include groups in which one or more hydrogen atoms have been removed from bicycloalkane, tricycloalkane, tetracycloalkane, and the like. Specific examples include groups in which one or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane or tetracyclododecane. Many such polycyclic groups have been proposed in polymers (resin components) for resist compositions for ArF excimer lasers, and can be appropriately selected from those used. Among these polycyclic groups, a group obtained by removing two or more hydrogen atoms from adamantane, a group obtained by removing two or more hydrogen atoms from norbornane, a group obtained by removing two or more hydrogen atoms from tetracyclododecane, Group Is industrially preferred.

[0041] As the structural unit (a3), when the hydrocarbon group in the polar group-containing aliphatic hydrocarbon group is a linear or branched hydrocarbon group having 1 to LO carbon atoms, the hydroxy group of acrylic acid is used. Preferred structural units derived from tilesters When the hydrocarbon group is a polycyclic group, a structural unit represented by the following formula (a3-1), a structural unit represented by (a3-2), The structural unit represented by (a3-3) is preferable.

[0042] [Chemical 14]

(a3-3)

[Wherein R is the same as defined above, j is an integer of 1 to 3, k is an integer of 1 to 3, t ′ is an integer of 1 to 3, and 1 is 1 to 3] (It is an integer of 5 and s is an integer of 1 to 3.)

In formula (a3-l), j is preferably 1 or 2, and more preferably 1. When j is 2, it is preferable that the hydroxyl group is bonded to the 3rd and 5th positions of the adamantyl group. When j is 1, it is preferable that the hydroxyl group is bonded to the 3-position of the adamantyl group. j is preferably 1, and in particular, a hydroxyl group bonded to the 3-position of the adamantyl group is preferred.

In the formula (a3-2), k is preferably 1. The cyan group is preferably bonded to the 5th or 6th position of the norbornyl group.

In formula (a3-3), t ′ is preferably 1. 1 is preferably 1. s is preferred to be 1,. These preferably have a 2-norbornyl group or a 3-norbornyl group bonded to the terminal of the carboxy group of acrylic acid. Fluorinated alkyl alcohol Is preferably bonded to the 5th or 6th position of the norbornyl group! /,! /.

As the structural unit (a3), one type may be used alone, or two or more types may be used in combination.

When the polymer compound (A) has a structural unit (a3), the proportion of the structural unit (a3) in the polymer compound (A) is based on the total structural units constituting the polymer compound (A). 10 to 60 mol%, preferably 15 to 45 mol% in the gesture et preferred that a, most preferably more preferably 15 to 3 5 mole ^o / _zero.

[0048] [Structural unit (a4)]

The polymer compound (A) may contain other structural units (a4) other than the structural units (al) to (a3) as long as the effects of the present invention are not impaired.

The structural unit (a4) is not classified into the above structural units (al) to (a3)! Other structural units are not particularly limited. Conventionally, they are also known for use in resist resins such as for ArF excimer lasers and for KrF positive excimer lasers (preferably for ArF excimer lasers). Many of these are available.

As the structural unit (a4), for example, a structural unit containing a non-acid-dissociable aliphatic polycyclic group and also inducing acrylate ester power is preferable.

Examples of the polycyclic group include the same polycyclic groups as those exemplified as the aliphatic cyclic group in the structural unit (al). For ArF excimer laser, KrF positive A number of hitherto known materials can be used for the resin component of resist yarns and compositions such as for excimer lasers (preferably for ArF excimer lasers). In particular, at least one kind selected from tricyclodecanyl group, adamantyl group, tetracyclododecyl group, isobornyl group and norbornyl group is preferable in terms of industrial availability. These polycyclic groups may have a linear or branched alkyl group having 1 to 5 carbon atoms as a substituent.

Specifically, as the structural unit (a4), those having the structures of the following general formulas (a4-l) to (a4-5) can be shown in column f.

[0049] [Chemical 15]

[0050] (In the formula, R is the same as defined above.)

[0051] The powerful structural unit (a4) is not an essential component of the polymer compound (A), but when it is contained in the polymer compound (A), all of the constituents of the polymer compound (A) are included. It is preferable to contain 1 to 30 mol%, preferably 10 to 20 mol% of the structural unit (a4) with respect to the total of the structural units.

[0052] The polymer compound (A) is obtained by polymerizing a monomer for deriving each structural unit by, for example, a known radical polymerization using a radical polymerization initiator such as azobisisobutyl-tolyl (AIBN). This can be obtained.

In addition, the polymer compound (A) may be subjected to, for example, HS—CH—CH—CH

twenty two

— C (CF) — When used together with a chain transfer agent such as OH, one C (CF

2 3 2

) One OH group may be introduced. In this way, some of the hydrogen atoms of the alkyl group are

3 2

Copolymers introduced with hydroxyalkyl groups substituted with a polymer can reduce development defects.

Effective for reducing LER (Line Edge Roughness: Uneven irregularities on the side wall of the line). [0053] The mass average molecular weight (Mw) of the polymer compound (A) (polystyrene conversion standard by gel permeation chromatography) is not particularly limited, but 3000-50000 force S preferred <, 3000-30000 Preferred over force <, 5000-20000 force most preferred! / !. If it is smaller than the upper limit of this range, it has sufficient solubility in a resist solvent to be used as a resist, and the dry etching resistance and resist pattern cross-sectional shape that are larger than the lower limit of this range are good.

Further, the degree of dispersion (Mw / Mn) i is preferably 1.0 to 5.0 force S, more preferably 1.0 to 3.0 force S, and most preferably 1.0 to 2.5.

[0054] Kusu positive resist yarn and composition>

The positive resist composition of the present invention contains the polymer compound (A) of the present invention (hereinafter, also referred to as “component (A)”) as a base resin component, and is exposed to an acid by irradiation (exposure). An acid generator (hereinafter referred to as component (B)).

Since the component (A) has a structural unit (al) that is a structural unit having a V-sodic acid dissociable, dissolution inhibiting group, it is insoluble in alkali before exposure and is generated from the component (B) by exposure. When the acid acts, the acid dissociable, dissolution inhibiting group is dissociated, thereby increasing the alkali solubility of the entire component (A) as well as the alkali-insoluble key. Therefore, in the formation of a resist pattern, if selective exposure is performed on the resist, or if post-exposure heating (PE B) is performed in addition to exposure, the exposed area turns to alkali-soluble, while the unexposed area. Since the alkali remains insoluble and does not change, a positive resist pattern can be formed by alkali development.

[0055], (B) component

The component (B) is not particularly limited, and those that have been proposed as acid generators for chemical amplification resists can be used. Examples of such acid generators include onium salt-based acid generators such as ododonium salts and sulfo-um salts, oxime sulfonate-based acid generators, bisalkyl or bisarylsulfonyldiazomethanes. Various kinds of acid generators such as diazomethane acid generators such as poly (bissulfol) diazomethane, nitrobenzilsulfonate acid generators, iminosulfonate acid generators, and disulfone acid generators are known. [0056] Examples of the oum salt-based acid generator include compounds represented by the following general formula (b-1) or (b-2).

[0057] [Chemical 16]

R ⁴ 'S03… (b-2)

[In the formula, R ¹ "^ ³ ", R ⁵ "to R ⁶ " each independently represents an aryl group or an alkyl group; R ⁴ "represents a linear, branched or cyclic alkyl group or Represents a fluorinated alkyl group; at least one of,, to "represents an aryl group, and at least one of R ⁵ " to R ⁶ "represents an aryl group. ]

[0059] In formula (b-1),,, and ~ each independently represent an aryl group or an alkyl group. Among R ¹ "to R ³ ", at least one represents an aryl group. Of these, it is preferred that two or more are aryl groups. Most preferably, all of R ^{lw to} R ³ "are aryl groups.

The aryl group of R ^{lw to} R ³ "is not particularly limited, for example, an aryl group having 6 to 20 carbon atoms, in which part or all of the hydrogen atoms are alkyl groups, alkoxy groups. It may not be substituted with a group, a halogen atom, etc. The aryl group is preferably an aryl group having 6 to 7 carbon atoms because it can be synthesized at low cost. For example, a phenol group and a naphthyl group can be mentioned.

Examples of the alkyl group on which the hydrogen atom of the aryl group may be substituted are a methyl group, an ethyl group, a propyl group, an n-butyl group, and a tert-butyl group, which are preferably alkyl groups having 1 to 5 carbon atoms. It is most preferred.

As the alkoxy group that may be substituted with a hydrogen atom of the aryl group, a methoxy group and an ethoxy group are preferred, with an alkoxy group having 1 to 5 carbon atoms being preferred.

The halogen atom that may be substituted for the hydrogen atom of the aryl group is preferably a fluorine atom.

The “˜” alkyl group is not particularly limited, and examples thereof include a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms. From the point of excellent resolution, carbon number 1 ~ 5 is preferred. Specifically, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-pentyl group, a cyclopentyl group, a hexyl group, a cyclohexyl group, a nonyl group, A decanyl group and the like can be mentioned, and a methyl group can be mentioned as a preferable one because it is excellent in resolution and can be synthesized at low cost.

Among these! It is most preferred that all of the ~~ are phenolic groups! / ,.

[0060] R ⁴ "is a linear, branched or cyclic alkyl group or fluorinated alkyl group.

The straight chain alkyl group is most preferably 1 to 4 carbon atoms, more preferably 1 to 8 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 4 carbon atoms.

The cyclic alkyl group is a cyclic group as shown by the above R ¹ ″, preferably a carbon number of 4 to 15 carbon atoms, more preferably a carbon number of 4 to 10 carbon atoms. Most preferably, the number is from 6 to 10.

The fluorinated alkyl group is most preferably 1 to 4 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 4 carbon atoms. Also. The fluorination rate (ratio of fluorine atoms in the alkyl group) of the fluorinated alkyl group is preferably 10 to: LOO%, more preferably 50 to 100%, and in particular, all hydrogen atoms are fluorine atoms. The substituted one is preferable because the strength of the acid is increased.

R ⁴ ″ is most preferably a linear or cyclic alkyl group or a fluorinated alkyl group.

In the formula (b-2), R ⁵ ″ to R ⁶ ″ each independently represents an aryl group or an alkyl group. Of R 5, ˜˜R ⁶ , at least one represents an aryl group. Of R ⁵ "to R ⁶ ,, it is preferred that two or more are aryl groups. It is further preferred that all of R ⁵ " to R ⁶ "are aryl groups.

Examples of the aryl group of _R ⁵ "to _R ⁶ , include those similar to the aryl group of R1" to _R ³ ".

Examples of the alkyl group for R ⁵ "to R ⁶ " include the same alkyl groups as for,, to ".

Among these, it is most preferable that all of R ⁵ ″ to R ⁶ ″ are phenol groups. Those similar to - "(1 b) R ⁴ in the formula is as" the like R ⁴ of formula (b-2) in. [0062] Specific examples of the acid salt-based acid generator include trifluoromethane sulfonate or nonafluorobutane sulfonate of diphenylodium, trifluoromethanesulfonate or nona of bis (4-tertbutylbutyl) ododonium. Fluorobutane sulfonate, triphenyl sulfone trifluoromethane sulfonate, heptafluoropropane sulfonate or nonafluorobutane sulfonate, tri (4-methylphenol) snorephonium trifanololomethane sulphonate , Its heptafluororenopropane sulfonate or its nonafluorobutane sulfonate, dimethyl (4-hydroxynaphthyl) snorephonium trifanololemethane sulfonate, its heptafluororenopropane sulfonate Or its nonafluorobutane sulfonate, monophenyl dimethyl sulfone trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, diphenyl monomethyl sulfone trifluoro L-methanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, (4 methylphenol) diphenylsulfotrifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, (4- Methoxyphenyl) diphenyl sulfone trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, tri (4-tert-butyl) phenol Trifluoromethane sulfonate of rusulfo, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, diphenol (1- (6-methoxy) naphthyl) sulfo trifluoromethane sulfonate, Examples thereof include heptafluoropropane sulfonate and nonafluorobutane sulfonate. In addition, ohmic salts in which the ionic part of these ohmic salts is replaced with methane sulfonate, n propane sulfonate, n butane sulfonate, or n octane sulfonate can also be used.

[0063] Further, in the general formula (b-1) or (b-2), the anion part is replaced with a caron part represented by the following general formula (b-3) or (b-4) (The cation moiety is the same as (b-1) or (b-2)).

[0064] [Chemical 17] … (B-4)

[0065] [wherein X "represents a C 2-6 alkylene group in which at least one hydrogen atom is substituted with a fluorine atom; Υ", Ζ "each independently represents at least one hydrogen Represents an alkyl group having 1 to 10 carbon atoms in which the atom is substituted with a fluorine atom.

[0066] X "is a linear or branched alkylene group in which at least one hydrogen atom is substituted with a fluorine atom, and the alkylene group has 2 to 6 carbon atoms, preferably 3 to 3 carbon atoms. Five

Most preferably, it has 3 carbon atoms.

Υ "and Ζ" are each independently a linear or branched alkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and the alkyl group has 1 to 10 carbon atoms, preferably It is C1-C7, More preferably, it is C1-C3.

The carbon number of the alkylene group of X "or the carbon number of the alkyl group of Υ" and Ζ "is preferably as small as possible because it has good solubility in the resist solvent within the above carbon number range.ヽ.

In addition, in the alkylene group of X "or the alkyl group of Υ" and Ζ ", the greater the number of hydrogen atoms substituted with fluorine atoms, the stronger the acid strength and the higher the energy of 200 nm or less. And U is preferred because of its improved transparency to electron beams, and the proportion of fluorine atoms in the alkylene group or alkyl group, that is, the fluorination rate is preferably 70 to 100%, more preferably 90 to LOO%. Most preferably, it is a perfluoroalkylene group or a perfluoroalkyl group in which all hydrogen atoms are substituted with fluorine atoms.

[0067] Also, among the salt-based acid generators, an ohmic salt having a weak acid strength and having a camphor sulfonate ion in the key-on portion can be used. The cation moiety is the same as that represented by the general formula (b-1) or (b-2). Specific examples include compounds represented by the following chemical formula.

[0068] [Chemical 18]

[0069] An oxime sulfonate acid generator is a compound having at least one group represented by the following general formula (B-1), and has a property of generating an acid upon irradiation with radiation. Is. Such an oxime sulfonate acid generator can be arbitrarily selected and used.

[0070] [Chemical 19]

-

[0071] (In formula (B-1), R ^z R each independently represents an organic group.)

[0072] The organic group is a group containing a carbon atom and has an atom other than a carbon atom (for example, a hydrogen atom, an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom (fluorine atom, chlorine atom, etc.)). You may do it.

As the organic group for R ²¹ , a linear, branched or cyclic alkyl group or aryl group is preferable. These alkyl groups and aryl groups may have a substituent. The substituent is not particularly limited, and examples thereof include a fluorine atom and a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms. Here, “having a substituent” means that part or all of the hydrogen atoms of the alkyl group or aryl group are substituted with a substituent. As the alkyl group, 1 to 20 carbon atoms are preferable. 1 to 10 carbon atoms are more preferable. 1 to 8 carbon atoms are more preferable. 1 to 6 carbon atoms are particularly preferable. 1-4 carbon atoms are particularly preferable. Most preferred. As the alkyl group, a partially or completely halogenated alkyl group (hereinafter sometimes referred to as a halogenated alkyl group) is particularly preferable. Partially halogenated An alkyl group means an alkyl group in which some of the hydrogen atoms are substituted with halogen atoms, and a fully halogenated alkyl group means an alkyl group in which all of the hydrogen atoms are replaced with halogen atoms. means. Examples of the halogen atom include a fluorine atom, a chlorine atom, an fluorine atom, and an iodine atom, and a fluorine atom is particularly preferable. That is, the halogenated alkyl group is preferably a fluorinated alkyl group! /.

The aryl group is preferably 4 to 20 carbon atoms, preferably 4 to 20 carbon atoms, and most preferably 6 to 10 carbon atoms, more preferably L0. As the aryl group, a partially or completely halogenated aryl group is particularly preferable. A partially halogenated aryl group means an aryl group in which a part of hydrogen atoms is replaced with a halogen atom, and a completely halogenated aryl group means that all hydrogen atoms are halogenated. An aryl group substituted with an atom.

R ²¹ is particularly preferably an alkyl group having 1 to 4 carbon atoms having no substituent or a fluorinated alkyl group having 1 to 4 carbon atoms.

[0073] As the organic group for R ²² , a linear, branched, or cyclic alkyl group, aryl group, or cyan group is preferable. Examples of the alkyl group and aryl group for R ²² include the same alkyl groups and aryl groups as those described above for R ²¹ .

R ²² is particularly preferably a cyano group, an alkyl group having 1 to 8 carbon atoms having no substituent, or a fluorinated alkyl group having 1 to 8 carbon atoms.

[0074] More preferable examples of the oxime sulfonate acid generator include compounds represented by the following general formula (B-2) or (B-3).

[0075] [Chemical 20]

…-

[In the formula (B-2), R ³¹ represents a cyano group, an alkyl group having no substituent, or a halogenalkyl group. R ³² is an aryl group. R ³³ is an alkyl group having no substituent or a halogenated alkyl group. ]

[0077] [Chemical 21]

[In the formula (B-3), a cyano group, an alkyl group or a halogenalkyl group having no substituent. R ³⁵ is a divalent or trivalent aromatic hydrocarbon group. R ³⁶ is an alkyl group having no substituent or a halogenated alkyl group. p is 2 or 3. ]

[0079] In the general formula (B-2), the alkyl group or halogenated alkyl group having no substituent of R ³¹ preferably has 1 to L0 carbon atoms. 1 to 8 carbon atoms are more preferred. 1 to 6 carbon atoms are most preferred.

R ³¹ is more preferably a fluorinated alkyl group, preferably a halogenated alkyl group.

The fluorinated alkyl group for R ³¹ is preferably fluorinated with 50% or more of the hydrogen atom of the alkyl group, more preferably 70% or more, and even more preferably 90% or more. I like it! /

[0080] The aryl group of R ³² is an aromatic hydrocarbon such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthracyl group, a phenanthryl group, and the like. Ring force A group in which one hydrogen atom is removed, and a heteroaryl group in which a part of the carbon atoms constituting the ring of these groups are substituted with a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. Can be mentioned. Among these, a fluorenyl group is preferable.

The aryl group of R ³² may have a substituent such as an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group, or an alkoxy group. The alkyl group or halogenated alkyl group in the substituent preferably has 1 to 4 carbon atoms, more preferably 1 to 4 carbon atoms. The halogenated alkyl group is preferably a fluorinated alkyl group.

[0081] The alkyl group having no substituent of R ³³ or the halogenated alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and more preferably 1 to 6 carbon atoms. Most preferred.

R ³³ is preferably a fluorinated alkyl group, preferably a halogenated alkyl group, more preferably a partially fluorinated alkyl group.

In the fluorinated alkyl group for R ^33, 50% or more of the hydrogen atoms in the alkyl group are fluorinated. More preferably, it is fluorinated by 70% or more, more preferably 90% or more, since the strength of the acid generated increases. Most preferably, it is a fully fluorinated alkyl group in which a hydrogen atom is 100% fluorine-substituted.

In the general formula (B-3), the alkyl group or the halogenated alkyl group having no substituent of R ³⁴ is an alkyl having no substituent of the above R ^31. Examples thereof are the same as the group or the halogenalkyl group.

Examples of the divalent or trivalent aromatic hydrocarbon group for R ³⁵ include groups in which the aryl group strength of R ³² is one or two hydrogen atoms.

Do no substituent of R ^36, the alkyl group or Harogeni spoon alkyl group, the same alkyl group or Harogeni spoon alkyl group containing no substituent group of the ³ mentioned et be.

p is preferably 2.

[0083] Specific examples of the oxime sulfonate-based acid generator include α- (ρ-toluenesulfo-luoximino) -benzyl cyanide, α- (ρ-chlorobenzenesulfo-roximino) -benzil cyanide, _α- (4-Nitrobenzenesulfo-luximino) -benzyl cyanide, α- (4-Nitro-2-trifluoromethylbenzenesulfo-luoximino) -benzyl cyanide, a- (Benzenesulfo-roximino) -4 -Black Benzyl Cyanide, a-(Benzenesulfo-Luximinomino)-2, 4-Dichlorobenzil Cyanide, α-(Benzenesulfo-Luximino Mino) -2, 6 -Dichlorobenzil Cyanide, α-( Benzenesulfo-luoxyimino) -4-methoxybenzyl cyanide, α- (2-chlorobenzenesulfo-roximino) -4-methoxybenzil cyanide, a- (benzenesulfo- Oximino) -Chen-2-ylacetonitrile, a- (4-dodecylbenzenesulfo-ruximino) -benzyl cyanide, α-[(p-toluenesulfo-ruximino) -4-methoxyphenyl] acetonitrile, at- [(Dodecylpen sensulfo-luoxyimino) -4-methoxyphenyl] acetonitrile, at- (tosyloxymino) -4-cell cyanide, _α- (methylsulfo-ruximino) -1 -cyclopentalacetonitrile, (X-( Methylsulfo-ruximino)-1 -cyclohex-l-acetonitrile, α-(Methylsulfo-ruximino)-1 -cyclohepturacetonitrile, α-(Methylsulfo-ruximino)-1 -cyclootatulacetonitrile, _α- (Trifluoromethyls Rupho-Luoxyimino)-1 -Cyclopente-Luacetonitrile, α-(Trifluoromethylsulfo-Luoxyimino) -Cyclohexylacetonitrile, α-(Ethylsulfo-Luoxymino) -Ethylacetonitrile, _α- (Propyl) Sulfo-Luoxyimino) -Propylacetononitrile, α- (Cyclohexylsulfonyloxyimino) -Cyclopentylacetonitrile, α- (Cyclohexylsulfo-Luoxyimino) -Cyclohexylacetonitrile, H- (Cyclohexionitrile) Hexylsulfo-Luoxyimino)-1 -Cyclopente-Luacetonitrile, α-(Ethylsulfo-Luoxyimino)-1 -Cyclopente-Luacetonitrile, H-(Isopropylsulfo-Luoxyimino)-1 -Cyclopente-Luacetonitrile, (X-(η-Butylsulfo) -Luximimino)-1- Clopenteru-nitronitrile, at- (Ethylsulfo-Luoxyimino)-1 -Cyclohexa-Lucetonitrile, OC-(Isopropylsulfo-Luoximino) -1 -Cyclohexe-Luaceto-Tolyl, α-(η-Butylsulfo-Luoximino)-1 -Cyclohexylacetonitrile, _α — (Methylsulfo-ruximinomino) pheulacetonitrile, α (Methylsulfonyloximino) -ρ-methoxyphenylacetonitrile, α (trifluoromethylsulfo-ruximinomino) pheulacetonitrile, α (Triflur) Chloromethylsulfo-methoxy) ρ-methoxyphenylacetonitrile, ひ (ethylsulfo-sulfoximino) -ρ-methoxyphenylacetonitrile, (X- (propylsulfoxy-imino)) ρ methylphenol-α, α Mechirusuruho - Ruokishiimino) -ρ Breakfast Romofue - Ruasetonitoriru and the like.

Moreover, the compound represented by the following chemical formula is mentioned.

[Chemical 22]

CH ₃ — 0 ₂ S— O—— N = C--C = —— O—— SO _z —— CH ₃

NC CN

CH ₃ — 0 ₂ S— O— N = C ~ -C = —— O One S0 ₂ — CH ₃

_CN CN

C4H9-O2S― O—— N = C ~ -C = N One O— S0 ₂ — C ₄ H ₉

CM CN

CF ₃ — 0 ₂ S— O— N = C ~ C = N—— 0— S0 ₂ — CF ₃

_CN CN

CH ₃ -C = N-0S02-CCH ₂ ) 3CH ₃

CH3- C = H-0SO2- (CH2) ₃ CH ₃

[0085] Among the compounds represented by the general formula (B-2) or (B-3), examples of preferable compounds are shown below.

[0086] [Chemical 23]

twenty four]

^ -C = N— O— S0 ₂ — CF ₉

(CF ₂ } ₆ — H

[0088] Among the above exemplified compounds, the following three compounds are preferable: [0089] [Chemical Formula 25]

[0090] [Chemical 26]

CH3- C = N-OS0 _2- (CH ₂ ) 3CH ₃

CH ₃ -C = N-0S02- (CH ₂ ) 3CH3

[0091] [Chemical 27]

[0092] Among diazomethane acid generators, specific examples of bisalkyl or bisarylsulfol diazomethanes include bis (isopropylsulfol) diazomethane, bis (p-toluenesulfol) diazomethane, bis ( 1,1-dimethylethylsulfol) diazomethane, bis (cyclohexylsulfol) diazomethane, bis (2,4-dimethylphenylsulfol) diazomethane and the like.

Poly (bissulfonyl) diazomethanes include, for example, 1,3-bis (phenylsulfol diazomethylsulfol) propane (compound A), 1, 4 having the structure shown below. -Bis (phenylsulfodiazomethylsulfo) butane (Compound B), 1,6-bis (phenolsulfoldiazomethylsulfol) hexane (Compound C) ), 1,10-bis (phenylsulfol-diazomethylsulfol) decane (compound D), 1,2-bis (cyclohexylsulfol-diazomethylsulfol) ethane ( Compound E), 1,3-bis (cyclohexylsulfazodiazomethylsulfol) propane (Compound F), 1,6-bis (cyclohexylsulfazodiazomethylsulfo- ) Hexane (Compound G), 1,10-bis (diethylhexylsulfol diazomethylsulfol) de Can (a compound H).

[0093] [Chemical 28]

Among them, as the component (B), an onium salt having a fluorinated alkyl sulfonate ion as a ion, a diazomethane acid generator, and a onium salt force having a camphor sulfonate ion in the cation is also selected. One type is preferably used. Of these, an onium salt having a fluorine alkyl sulfonate ion as a key is more preferable.

As the component (B), these acid generators may be used alone or in combination of two or more (a combination of an onium salt and a diazomethane acid generator or an oxime sulfonate acid generator). You can use in combination.

The content of the component (B) in the positive resist composition of the present invention is 0.5 to 30 parts by mass, preferably 1 to: LO parts by mass with respect to 100 parts by mass of the component (A). By making it in the above range, pattern formation is sufficiently performed. Further, it is preferable because a uniform solution can be obtained and storage stability is improved.

, (D) component

In the positive resist composition of the present invention, a nitrogen-containing organic compound (D) (hereinafter referred to as (D) component) is further added as an optional component in order to improve the resist pattern shape, stability with time, and the like. ) Can be blended.

Since a wide variety of components (D) have already been proposed, any known one may be used, but aliphatic amines, particularly secondary aliphatic amines and tertiary aliphatic amines are preferred. .

Aliphatic amines contain at least one hydrogen atom of ammonia NH and have 12 or more carbon atoms.

Three

Examples include amines substituted with the lower alkyl group or hydroxyalkyl group (alkylamines or alkylalcoholamines). Specific examples thereof include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-noramine, n-decylamine; jetylamine, di-n-propylamine, di-n-heptylamine, di- --N-octylamine, dialkylamines such as dicyclohexylamine; trimethylamine, triethylamine, tri- _n -propylamine, tri-n-butylamine, tri-n-hexylamine, tri-n-pentylamine, tri-n-heptylamine, Trialkylamines such as tri-n-octylamine, tri-n-no-lamine, tri-n-de-ramine, tri-n-dodecylamine; diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine Min, _di-n - Okutanoruami , Alkyl alcohol § Min such as tree n- O click pentanol § Min and the like. Of these, alkyl alcoholamines are preferred, with alkyl alcoholamines and trialkylamines being preferred. Of the alkyl alcoholamines, triethanolamine is most preferably triisopropanolamine.

These can be used alone or in combination of two or more. Component (D) is usually used in the range of 0.01 to 5.0 parts by mass per 100 parts by mass of component (A).

[0096], (E) component

In addition, the positive resist composition of the present invention includes an organic carboxylic acid as an optional component for the purpose of preventing sensitivity deterioration due to the blending of the component (D) and improving the resist pattern shape and stability of placement. Acid or phosphorus oxoacid or its derivative (E) (hereinafter referred to as component (E)) can be contained. In addition, the component (D) and the component (E) can be used in combination, or one force can be used.

As the organic carboxylic acid, for example, malonic acid, citrate, malic acid, succinic acid, benzoic acid, salicylic acid and the like are suitable.

Phosphoric acid or its derivatives include phosphoric acid, phosphoric acid di-n-butyl ester, phosphoric acid diphenol ester and other phosphoric acid or derivatives such as those esters, phosphonic acid, phosphonic acid dimethyl ester, phosphonic acid Phosphonic acid such as n-butyl ester, phenol phosphonic acid, diphosphoric phosphonic acid ester, dibenzyl phosphonic acid ester and derivatives thereof, phosphinic acid such as phosphinic acid, phenol phosphinic acid and the like And derivatives such as esters, of which phosphonic acid is particularly preferred.

Component (E) is used in a proportion of 0.01 to 5.0 parts by mass per 100 parts by mass of component (A).

[0097] 'Organic solvent

The positive resist composition of the present invention can be produced by dissolving the material in an organic solvent.

As the organic solvent, it is sufficient if each component to be used can be dissolved into a uniform solution. Conventionally, any one or two of the known solvents for chemically amplified resists can be used. These can be appropriately selected and used.

For example, latones such as γ-butyrolatatane, ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone, 2-heptanone, ethylene glycol, ethylene glycol monoacetate, diethylene glycol, diethylene glycol Monoacetate, propylene glycol, propylene glycol monoacetate, dipropy Polyhydric alcohols such as lenglycol or dipropylene glycol monoacetate monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether or monophenyl ether and derivatives thereof, cyclic ethers such as dioxane, Mention may be made of esters such as methyl lactate, ethyl acetate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate, and the like.

[0098] These organic solvents may be used alone or as a mixed solvent of two or more.

A mixed solvent obtained by mixing propylene glycol monomethyl ether acetate (PGMEA) and a polar solvent is preferable. The mixing ratio (mass ratio) may be appropriately determined in consideration of the compatibility between PGMEA and the polar solvent, preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. Preferably within range! /.

More specifically, when EL is blended as a polar solvent, the mass ratio of PGMEA: EL is preferably 1: 9-9: 1, more preferably 2: 8-8: 2! / ,.

In addition, as the organic solvent, a mixed solvent of at least one selected from among PGMEA and EL and γ-petit-mouth rataton is also preferable. In this case, the mixing ratio of the former and the latter is preferably 70: 30-95: 5.

The amount of the organic solvent used is not particularly limited, but it is a concentration that can be applied to a substrate and the like, and is appropriately set according to the coating film thickness. Generally, the solid content concentration of the resist composition is 2 to 20 mass. %, Preferably 5-15% by mass.

[0099] · Other optional ingredients

The positive resist composition of the present invention further contains miscible additives as desired, for example, additional grease for improving the performance of the resist film, surfactant for improving coating properties, and dissolution inhibition. Agents, plasticizers, stabilizers, colorants, antihalation agents, dyes, and the like can be appropriately added and contained.

[0100] <Resist pattern formation method>

The resist pattern forming method of the present invention can be performed, for example, as follows. That is, first, the positive resist composition is applied onto a substrate such as a silicon wafer with a spinner or the like, and the pre-beta is preferably applied for 40 to 120 seconds under a temperature condition of 80 to 150 ° C. Preferably, it is applied for 60 to 90 seconds to form a resist film.

Next, the resist film is selectively exposed to a single ArF excimer laser beam through a desired mask pattern using, for example, an ArF exposure apparatus, and then subjected to PEB (post-exposure heating under a temperature condition of 80 to 150 ° C. ) For 40 to 120 seconds, preferably 60 to 90 seconds.

Then alkali developing solution, for example 0.1 to 10 mass ^_0/0 tetramethylammonium - developing is conducted using an Umuhido port Kishido solution. In this way, a resist pattern faithful to the mask pattern can be obtained.

An organic or inorganic antireflection film can be provided between the substrate and the coating layer of the resist composition.

[0101] The wavelength used for the exposure is not particularly limited, ArF excimer laser, KrF excimer laser, F excimer laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), EB (electron beam),

2

It can be performed using radiation such as X-rays and soft X-rays. In particular, the photoresist yarn and composition that is useful in the present invention are effective for ArF excimer lasers.

[0102] According to the present invention, as the structural unit (al) having an acid dissociable, dissolution inhibiting group, two or more kinds selected from the structural unit group force represented by the general formula (al — 01) or (al — 02) By using in combination, high resolution, suppression of pattern collapse, and good pattern shape can be achieved at the same time.

Using only one of the structural unit groups can satisfy one or two characteristics of high resolution, suppression of pattern collapse, and good pattern shape, but the remaining Although the reason is not clear by using two or more kinds of structural units, the shortcomings that do not detract from the advantages of each structural unit are improved, and all of the above characteristics are satisfied. It becomes possible.

The combination of structural units (al) is used in particular by combining Y in the above general formula with a substituent on its ring skeleton and Y having no substituent on its ring skeleton. It is preferable.

Among them, it is more preferable to use a combination of Y in the above general formula having a polar group as a substituent on the ring skeleton and a group in which Y does not have a substituent on the ring skeleton. . For example, as shown in the examples to be described later, when only the structural unit in which Y has a polar group is used as the structural unit (al), high resolution is obtained in which pattern collapse hardly occurs. Inferior to the rectangularity, such as skirting in the turn shape and rounding of the top (TOP) of the resist pattern. This is presumably because the polar group enhances the adhesion between the substrate and the pattern. On the other hand, if only the structural unit with no substituent is used as the structural unit (al), the pattern shape is slightly a tee-top (T-TOP) shape, and the pattern is likely to collapse. Surprisingly, when both structural units are used in combination, it is possible to obtain a high resolution that is unlikely to cause pattern collapse, and a pattern shape that is as good as the latter. It is done.

Example

[0103] [Synthesis Example 1] Synthesis of (2 adamantyloxy) methyl methacrylate

6. 9 g of methacrylic acid was dissolved in 200 mL of tetrahydrofuran and triethylamine 8. Og was added. After stirring at room temperature, lOOmL of tetrahydrofuran in which 15 g of 2-adamantyl chloromethyl ether was dissolved was added dropwise. After stirring at room temperature for 12 hours, the precipitated salt was filtered off. The obtained filtrate was evaporated, dissolved in 200 mL of ethyl acetate, washed with pure water (100 mL × 3), and evaporated. A white solid was obtained after standing under ice cooling.

The obtained compound 1 ((2-adamantoxymethyl) metatalylate) is represented by the following chemical formula.

Infrared absorption spectrum (IR) and proton nuclear magnetic resonance spectrum (—NMR) are shown. IR (cm— ¹ ): 2907, 2854 (C—H stretch), 1725 (C = 0 stretch), 1638 (C = C stretch) ¹ H—NMR (CDC1, internal standard: tetramethylsilane) ppm: 1. 45 ~ 2.1 (m

Three

17H), 3.75 (s, 1H), 5.45 (s, 2H), 5.6 (s, 1H), 6.12 (s, 1H)

[0104] [Chemical 29]

[0105] [Synthesis Example 2] (Synthesis of 4-oxo-2 Adama: 2. 2 g of methacrylic acid was dissolved in 50 mL of tetrahydrofuran, and 2.5 g of triethylamine was calored. After stirring at room temperature, 50 mL of tetrahydrofuran in which 4.3 g of 4-oxo-2adamantyl chloromethyl ether was dissolved was added dropwise. After stirring for 12 hours at room temperature, the precipitated salt was filtered off. The obtained filtrate was evaporated, dissolved in lOOmL of ethyl acetate, washed with pure water (50 mL X 3), and evaporated. A white solid was obtained after standing under ice cooling. The obtained compound 2 ((4-oxo-2 adamantyloxy) methyl metatalylate) is represented by the following chemical formula.

Infrared absorption spectrum (IR) and proton nuclear magnetic resonance spectrum (—NMR) are shown. IR (cm— ¹ ): 2926, 2861 (C—H stretch), 1725 (C = 0 stretch), 1636 (C = C stretch) ¹ H—NMR (CDC1, internal standard: tetramethylsilane) ppm: 1 .62-3.85

Three

(m, 15H), 4.2 (s, 1H), 5.4 (s, 2H), 5.65 (s, 1H), 6.15 (s, 1H)

[0106] [Chemical 30]

[0107] [Synthesis Example 3] Synthesis of polymer compound (A)

10. Og of (2-adamantyloxy) methyl methacrylate obtained in Synthesis Example 1; 10.6 g of (4 oxo-2 adamantyloxy) methyl methacrylate obtained in Synthesis Example 2; γ Dissolve 13.6 g of butyrolatatatone methacrylate (GBLMA) and 9.5 g of 3-hydroxy-1-adamantylmethalate in 200 ml of tetrahydrofuran, and add 1.64 g of azobisisobutyrate-tolyl. Yeah. After refluxing for 12 hours, the reaction solution was added dropwise to 1 L of n-heptane. The precipitated rosin was separated by filtration and dried under reduced pressure to obtain a white powdered rosin. The structural formula of this resin 1 (polymer compound (A)) is shown below.

The weight average molecular weight (Mw) of rosin 1 was 10300, and the degree of dispersion (MwZMn) was 1.78. Further, as a result of measuring carbon 13 nuclear magnetic resonance spectrum ( ¹³ C-NMR), the composition ratio of each structural unit represented by the following structural formula was ml: m2: n: l = 0.0.2: 0.2: 0.4 : 0.2 (molar ratio). [0108] [Chemical 31]

[0109] [Comparative Synthesis Example 1]

20. Og of (2-adamantyloxy) methylmethallate obtained in Synthesis Example 1; 13.6 g of γ-butyrolataton methacrylate; and 9.9 of 3 hydroxy 1-adamantyl methacrylate. 5 g was dissolved in 200 mL of tetrahydrofuran, and 1.64 g of azobisisobutyl-tolyl was obtained. After refluxing for 12 hours, the reaction solution was added dropwise to 2 L of n-heptane. The precipitated rosin was separated by filtration and dried under reduced pressure to obtain a white powdered rosin. The structural formula of this resin 2 is shown below.

The molecular weight (Mw) of rosin 2 was 9700, and the degree of dispersion (MwZMn) was 1.88. As a result of measuring carbon 13 nuclear magnetic resonance spectrum ( ¹³ C-NMR), the composition ratio in the formula was m: n: l = 0.4: 0.4: 0.2 (molar ratio). .

[0110] [Chemical 32]

[0111] [Comparative Synthesis Example 2]

(1) Og of (4 oxo-2 adamantyloxy) methyl metatalylate obtained in Synthesis Example 2; 13.6 g of γ-butyrolatatatone methacrylate; and 3 hydroxy 1 adamantyl metatalylate. 9. 5 g was dissolved in 200 ml of tetrahydrofuran, and 1.64 g of azobis sobuchi-tolyl was added. After refluxing for 12 hours, the reaction solution was added dropwise to 1 L of n-heptane. The precipitated rosin was separated by filtration and dried under reduced pressure to obtain a white powdered rosin. The structural formula of this resin 3 is shown below.

Coffin 3 had a weight average molecular weight (Mw) of 10,200 and a dispersity (MwZMn) of 1.72. Further, as a result of measuring carbon 13 nuclear magnetic resonance spectrum ( ¹³ C-NMR), the composition ratio of each structural unit shown in the following structural formula was m: n: 1 = 0.0.4: 0.4: 0.2 (mol Ratio).

[0112] [Chemical 33]

[0113] [Example 1] Preparation and evaluation of positive resist composition

A positive resist composition was prepared using the resin 1 synthesized in Synthesis Example 3 and the following acid generator, nitrogen-containing organic compound, and solvent.

Oil 1 100 parts by mass

Acid generator: TPS- PFBS 3.5 parts by mass

Nitrogen-containing organic compound: Triethanolamine 0.35 parts by mass

Solvent: PGMEA: 750 parts by mass of mixed solvent of EL = 6: 4 (mass ratio)

[0114] "TPS-PFBS" represents triphenylsulfo-munonafluorobutane sulfonate. "

PGMEAJ represents propylene glycol monomethyl ether acetate. EL represents lactic acid ethyl.

[0115] A resist pattern was formed using the positive resist composition obtained above.

That is, first, apply an organic antireflective coating composition “ARC-29” (trade name, manufactured by Plue Science) on an 8-inch silicon wafer using a spinner, and then 215 ° C. for 90 seconds on a hot plate. By baking and drying, an organic antireflection film having a thickness of 77 nm was formed.

Next, the positive resist composition obtained above is applied onto the antireflection film using a spinner, pre-beta (PAB) at 95 ° C. for 90 seconds on a hot plate, and dried to obtain a film thickness. A 225 nm resist film was formed.

Subsequently, an ArF excimer laser (193 nm) was applied to the resist film using an ArF exposure system NSR-S302A (Nikon; NA (numerical aperture) = 0.60, 2Z3 annular illumination) and a mask pattern (binary). -Selectively exposed through a mask) to perform selective exposure.

Then, a PEB treatment was conducted under conditions of 105 ° C, 90 seconds, further 23 ° C at 2.38 mass ^_0/0 tetra Mechiruanmo - 60 seconds and puddle developed with Umuhidorokishido (TMAH) aqueous solution, then washed for 20 seconds with water Dried. Thus, a resist pattern was formed.

[0116] Evaluation of the positive resist composition was performed as follows.

When the sensitivity when a 140 nm line and space is formed 1: 1 is defined as EOP, the minimum pattern width that can be resolved by the EOP is defined as the ultimate resolution. Scanning electron microscope). Moreover, the cross-sectional shape of the pattern is observed by the SEM photograph. The results are shown in Table 1 below.

[0117] <Pattern collapse>

As the exposure time in selective exposure was increased, the pattern collapse was observed by SEM when the width of the pattern gradually narrowed accordingly. The results are as follows: (1) When the exposure time is gradually increased and the amount of exposure when the pattern starts to fall is T, the value of (TZEOP) X 100 (unit:%) is set to “collapse m (collapse m (2) The exposure time was gradually increased, and the pattern width (unit: nm) when the pattern collapse started to occur was determined as the collapse pattern size.

These results are shown in Table 1 below.

[0118] [Comparative Example 1]

A positive resist composition was prepared in the same manner as in Example 1 except that the resin 1 in Example 1 was replaced with the resin 2 synthesized in Comparative Synthesis Example 1, and the resist composition was used. A resist pattern was formed and evaluated.

The results are shown in Table 1 below.

[Comparative Example 2]

A positive resist composition was prepared in the same manner as in Example 1 except that the resin 1 in Example 1 was replaced with the resin 3 synthesized in Comparative Synthesis Example 2, and the resist composition was used. A resist pattern was formed and evaluated.

The results are shown in Table 1 below.

[0120] [Table 1]

As shown in the results of Table 1, Comparative Example 1 had a slightly T TOP shape, and the pattern collapsed easily and the resolution was insufficient. In Comparative Example 2, the resolution was good and the pattern collapse was suppressed. The rectangularity of the pattern was insufficient. Implemented against this In Example 1, a high resolution, a good pattern shape was obtained, and pattern collapse was also suppressed.

Industrial applicability

It is possible to provide a polymer compound capable of forming a resist pattern having high resolution, suppressed pattern collapse, and good shape, a positive resist composition containing the polymer compound, and a resist pattern forming method.

Claims

Claims At least two structural units selected from a structural unit represented by the following general formula (al—01) and a structural unit represented by the following general formula (al—02) ( al) a high molecular compound.

[Chemical 1]

C a 1-0 1) a 1-0 2)

[In the above formula, Y represents an aliphatic cyclic group; n represents 0 or an integer of 1 to 3;

R represents independently a hydrogen atom, a lower alkyl group having 1 to 5 carbon atoms, a fluorine atom or a fluorinated lower alkyl group having 1 to 5 carbon atoms; RR ² independently represents a hydrogen atom Alternatively, it represents a lower alkyl group having 1 to 5 carbon atoms. ]

[2] The polymer compound according to claim 1, wherein the (al) includes at least a structural unit represented by the general formula (al-01).

[3] (al) is a structural unit in which Y is an aliphatic cyclic group having a substituent on the ring skeleton, and Y does not have a substituent on the ring skeleton! 2. The polymer compound according to claim 1, comprising both structural units which are / aliphatic cyclic groups.

4. The polymer compound according to claim 3, wherein the substituent on the ring skeleton is a polar group.

[5] The polymer compound according to [1] having a structural unit (a2) derived from an acrylate ester having a latathone-containing monocyclic or polycyclic group.

[6] The polymer compound according to claim 1, having a structural unit (a3) derived from an acrylate ester containing a non-acid-dissociable polar group-containing aliphatic hydrocarbon group.

[7] The polymer compound according to claim 5, having a structural unit (a3) derived from an acrylate ester containing a non-acid-dissociable polar group-containing aliphatic hydrocarbon group.

[8] The proportion of the structural unit (al) is based on all structural units constituting the polymer compound.

2. The polymer compound according to claim 1, which is 10 to 80 mol%.

[9] The proportion of the structural unit (a2) is based on all structural units constituting the polymer compound.

6. The polymer compound according to claim 5, which is 10 to 80 mol%.

[10] The proportion of the structural unit (a3) is based on all structural units constituting the polymer compound.

The polymer compound according to claim 6, which is 10 to 60 mol%.

[11] The polymer compound according to [1], having a mass average molecular weight of 3,000 to 50,000.

[12] A positive resist composition comprising a resin component (A) whose alkali solubility is increased by the action of an acid, and an acid generator component (B) which generates an acid upon exposure,

The component (A) is a structural unit represented by the following general formula (al-01) and the following general formula (a

At least two structural units selected from the group consisting of the structural units represented by (1-02) (al

And a positive resist composition.

[Chemical 2]

0 1) (a 1-0 2)

1 represents R; each independently represents a hydrogen atom, a lower alkyl group having 1 to 5 carbon atoms,

[13] The (al) includes at least a structural unit represented by the general formula (al—01).

2. The positive resist composition as described in 2.

[14] The structural unit (al), wherein Y is an aliphatic cyclic group having a substituent on the ring skeleton, and Y has no substituent on the ring skeleton! 13. The positive resist composition according to claim 12, comprising both structural units which are / aliphatic cyclic groups.

15. The positive resist composition according to claim 14, wherein the substituent on the ring skeleton is a polar group.

16. The positive resist composition according to claim 12, wherein the component (A) has a structural unit (a2) derived from an acrylate ester having a latathone-containing monocyclic or polycyclic group.

[17] The (A) component, a positive type according to claim 12 having an acrylic acid Esuterukaゝet derived a structural unit containing a non-acid dissociable polar group-containing aliphatic hydrocarbon group _(a 3) Resist composition.

[18] The acrylic resin containing the non-acid-dissociable polar group-containing aliphatic hydrocarbon group as the component (A) 17. The positive resist composition according to claim 16, which has _a structural unit (a3) derived from an acid ester chain.

19. The positive resist composition according to claim 12, comprising a nitrogen-containing organic compound (D).

[20] A step of forming a resist film on a substrate using the positive resist composition according to any one of claims 12 to 19, a step of exposing the resist film, and an image of the resist film. And a step of forming a resist pattern.