JP2009288344A - Positive type resist composition and pattern forming method using the composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive type resist composition for new freezing processing made in the light of the above circumstances, not conducting special chemical processing to a first resist pattern in the freezing process, and capable of forming the first pattern having favorable line edge roughness without being substantially dissolved in a solvent of a second resist and a liquid developer without deteriorating the shape even when a second resist pattern is formed, and to provide a pattern forming method using the positive type resist composition. <P>SOLUTION: This positive type resist composition contains (A) resin, whose solubility to an alkaline liquid developer is increased by the action of acid, (B) a compound to which active light rays or radiation is applied to generate acid, and (C) a compound having a functional group which bridges between resins by heating. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a positive resist composition used in a semiconductor manufacturing process such as an IC, a circuit board such as a liquid crystal or a thermal head, and a lithography process for other photo applications, and a pattern forming method using the same. It is.

  In particular, the present invention relates to a positive resist composition suitable for exposure with a projection exposure apparatus (including immersion exposure) using far ultraviolet light having a wavelength of 200 nm or less as a light source, and a pattern forming method using the same. It is.

  Since the exposure light source has been shortened to 248 nm using a KrF excimer laser, an image forming method called chemical amplification and a resist composition suitable for it have been used as a resist image forming method in order to compensate for sensitivity reduction due to light absorption. Yes. An example of a positive-type chemical amplification image forming method will be described. When exposed, the acid generator in the exposed area decomposes to generate an acid, and the acid generated in the exposure bake (PEB) is a reaction catalyst. Is used to change an alkali-insoluble group to an alkali-soluble group, and an exposed portion is removed by alkali development.

  With the miniaturization of semiconductor elements, the wavelength of an exposure light source has been shortened and the projection lens has a high numerical aperture (high NA). Currently, an exposure machine using an ArF excimer laser having a 193 nm wavelength as a light source has been developed. The degree of achievement of miniaturization of a semiconductor element can be expressed by resolving power, and can be expressed by the following equation as is generally well known.

(Resolving power) = k ₁ · (λ / NA)
Here, λ is the wavelength of the exposure light source, NA is the numerical aperture of the projection lens, and k ₁ is a coefficient related to the process.

  As a technique for enhancing the resolving power, a so-called immersion exposure method in which a high refractive index liquid (hereinafter also referred to as “immersion liquid”) is filled between the projection lens and the sample has been proposed.

This “immersion effect” means that when λ ₀ is the wavelength of the exposure light in the air, n is the refractive index of the immersion liquid with respect to air, θ is the convergence angle of the light beam, and NA ₀ = sin θ. The above-described resolving power and depth of focus can be expressed by the following equations.

(Resolving power) = k ₁ · (λ ₀ / n) / NA ₀
That is, the immersion effect is equivalent to using an exposure wavelength having a wavelength of 1 / n. In other words, in the case of a projection optical system with the same NA, the depth of focus can be increased n times by immersion.

Further, as a technique for enhancing the resolution, a double patterning method has been proposed in which the circuit pattern is patterned by shifting it by half a pitch to increase the degree of integration (Non-Patent Document 1). This is a method corresponding to reducing k ₁ in the above-described resolving power equation. By using the double patterning method, as shown in FIG. 1, a desired resist pattern is formed twice in a first resist pattern forming process (steps a to d) and a second resist pattern forming process (steps e to h). It is possible to form a pattern having a pitch half that of the pitch p that can be formed by a single exposure process.

  That is, as shown in FIG. 1A, a layer made of a hard mask 102 is formed on a semiconductor substrate (including a lower layer film layer) 101, and a resist film is further formed on the hard mask 102. Next, as shown in FIG. 1B, the exposed resist film 103b and the unexposed resist film 103a are formed by performing pattern exposure on the formed resist film through the exposure mask 104, as shown in FIG. When a positive resist composition is used, a trench pattern having a space width p / 4 and a pitch p can be formed by developing the pattern as shown in FIG. Next, the hard mask 102 is etched using the resist pattern 103a as a mask, and the remaining resist pattern 103a is removed, whereby the resist pattern can be transferred onto the hard mask 102 as shown in FIG.

  Next, as shown in FIG. 1E, a resist film 105 is further formed on the hard mask 102 to which the pattern has been transferred. Next, as shown in FIG. 1 (f), the position of the exposure mask 106 is shifted by 1/2 pitch from the original position, and pattern exposure is performed through the exposure mask 106, whereby the exposed resist film 105b and When a positive resist composition is used, an unexposed resist film 105a is formed, and by developing the pattern, a trench having a space width p / 4 and a pitch p as shown in FIG. A pattern can be formed. Thereafter, the hard mask 102 is etched using the resist pattern 105a as a mask, and the remaining resist pattern 105a is removed, whereby a space width p / 4 and a pitch p are formed on the hard mask 102 as shown in FIG. / 2 pattern can be formed, and as a result, a pattern having a pitch ½ of the mask 104 (mask 106) used can be formed on the semiconductor substrate.

  As described in Non-Patent Document 3 and Non-Patent Document 4, the freezing process is performed so that the first resist pattern formed first does not dissolve in the solvent of the resist applied for the second time. The first resist pattern is subjected to some treatment so that it is not dissolved in the developer in the second development step, thereby substantially insolubilizing the resist solvent and developer to be applied the second time. A process that includes a process. By using the freezing process, it is possible to perform etching after continuing the lithography process from exposure to development twice, and it is possible to reduce the etching process after the first exposure. Here, “substantially insolubilized” with respect to the solvent and developer of the resist to be applied the second time means that the resist that has been applied the second time is insolubilized in the solvent. When the second resist solution is applied onto the resist pattern, the first resist film thickness decreased within the application time (typically within 60 seconds) is within 5% of the initial film thickness. Indicates that

In Patent Document 1, a processing agent for freezing containing a specific metal compound is allowed to act on a first resist pattern to form a metal oxide film, which is insolubilized in a resist solvent and a developer applied for the second time. A method has been proposed. In Non-Patent Document 1 and Non-Patent Document 2, a processing agent for freezing containing a specific resin and a crosslinking agent is allowed to act on the first resist pattern to form a film made of the resin composition of the processing agent. A method of insolubilizing a resist to be applied with a solvent and a developer has been proposed. Further, Patent Document 2 proposes a method of modifying a first resist pattern by irradiating the first resist pattern with vacuum ultraviolet rays so as to insolubilize the resist resist and a developing solution to be applied a second time. Yes.
JP 2008-33174 A JP 2005-197349 A Proceedings of SPIE, 6153, 615301 (2006) Proceedings of SPIE, 6923, 69230H (2008) Proceedings of SPIE, Vol. 6924, 69240R (2008) Proceedings of SPIE, 6520, 65200F (2007)

  However, in the conventional freezing process, the shape of the first resist pattern is deteriorated compared to the shape of the second resist pattern, and therefore the line edge roughness of the first resist pattern is deteriorated. It was a problem.

  The present invention has been made in view of the above circumstances, and does not substantially apply to the solvent and developer of the second resist without subjecting the first resist pattern to a special chemical treatment in the freezing process. A novel positive resist composition for freezing treatment, which can form a first pattern with good line edge roughness without being dissolved in the second resist pattern and without deteriorating the shape even after the second resist pattern is formed, Another object of the present invention is to provide a pattern forming method using the same.

  As a result of intensive studies to solve the above problems, the present inventor has reached the present invention shown below.

  (1) (A) a resin whose solubility in an alkaline developer is increased by the action of an acid, (B) a compound that generates an acid upon irradiation with actinic rays or radiation, and (C) a functional group that crosslinks between the resins by heating. And a positive resist composition containing the compound.

  (2) The positive resist composition according to (1), wherein the functional group that crosslinks between the resins by heating in the compound (C) is a blocked isocyanate group or a blocked thioisocyanate group.

  (3) The resin (A) is (a1) a repeating unit containing a group that decomposes by the action of an acid to generate an alkali-soluble group, and (a2) a functional group that crosslinks between the resins by heating in the compound (C). The positive resist composition according to (1) or (2), which has a repeating unit containing a group capable of reacting.

  (4) In the repeating unit (a2), a group capable of reacting with a functional group that crosslinks between resins by heating is a hydroxyl group, a carboxyl group, an amino group, an amide group, a thiol group, or an active methylene group. ) Positive resist composition.

  (5) The positive resist composition according to any one of (1) to (4), wherein the resin (A) further comprises (a3) a repeating unit having a lactone group.

(6) Furthermore,
(D) The positive resist composition according to any one of (1) to (5), comprising a compound containing a group capable of reacting with a functional group that crosslinks between resins by heating in the compound (C). .

  (7) In the compound (D), a group capable of reacting with a functional group that crosslinks between resins by heating is a hydroxyl group, a carboxyl group, an amino group, an amide group, a thiol group, or an active methylene group, (6) The positive resist composition as described in 1. above.

  (8) a first resist pattern forming step of forming a first resist pattern from the first resist film, a second resist film formed on the first resist pattern obtained in the step, Any one of (1) to (7), which is used for forming a first resist pattern in a resist pattern forming method including a second resist pattern forming step of forming a second resist pattern from the resist film. The positive resist composition as described in 1. above.

  (9) A step of forming a first photosensitive layer on the substrate using the positive resist composition according to any one of (1) to (8), and selectively the first photosensitive layer through a mask. A step of forming a first pattern by exposure and development, a step of heating the substrate on which the first pattern is formed, and a second positive resist composition on the heated substrate on which the first pattern is formed A method for forming a pattern, comprising: forming a second photosensitive layer by using a mask; and selectively exposing and developing the second photosensitive layer through a mask to form a second pattern.

  By using the resist composition of the present invention, the double patterning method does not substantially dissolve in the solvent and developer of the second resist, and the shape is deteriorated even after the second resist pattern is formed. Therefore, it is possible to provide a first resist pattern with good line edge roughness.

Hereinafter, the present invention will be described in detail.
In addition, in the description of a group (atomic group) in this specification, the description which does not describe substituted and unsubstituted includes what has a substituent with what does not have a substituent. For example, the “alkyl group” includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).

  In the present invention, after forming the first resist pattern on the first resist film, it is important to change the first resist pattern so as not to dissolve in the second resist solution and the developer by heat treatment. is there. This control can be achieved by changing the properties of the first resist and the process conditions (freezing treatment conditions) during the heat treatment.

  Below, the resist composition of this invention suitable as a 1st resist composition is explained in full detail.

  The positive resist composition of the present invention comprises (A) a resin that decomposes by the action of an acid and increases the solubility in an alkaline developer, (B) a compound that generates an acid upon irradiation with actinic rays or radiation, and (C) heating. And a compound having a functional group that crosslinks between the resins.

<(A) Resin whose solubility in an alkaline developer is increased by the action of an acid>
The resin of component (A) is a resin whose solubility in an alkaline developer is increased by the action of an acid. (A1) A group that decomposes by the action of an acid to generate an alkali-soluble group (hereinafter referred to as “acid-decomposable group”) And a repeating unit including a main chain or a side chain of the resin, or both of the main chain and the side chain.

  Alkali-soluble groups include phenolic hydroxyl groups, carboxyl groups, fluorinated alcohol groups, sulfonic acid groups, sulfonamido groups, sulfonylimide groups, (alkylsulfonyl) (alkylcarbonyl) methylene groups, (alkylsulfonyl) (alkylcarbonyl) imides. Group, bis (alkylcarbonyl) methylene group, bis (alkylcarbonyl) imide group, bis (alkylsulfonyl) methylene group, bis (alkylsulfonyl) imide group, tris (alkylcarbonyl) methylene group, tris (alkylsulfonyl) methylene group, etc. Is mentioned.

  Preferred alkali-soluble groups include carboxyl groups, fluorinated alcohol groups (preferably hexafluoroisopropanol), and sulfonic acid groups.

  A preferable group as the acid-decomposable group is a group obtained by substituting the hydrogen atom of these alkali-soluble groups with a group capable of leaving with an acid.

Examples of the group leaving with an acid include -C (R ₃₆ ) (R ₃₇ ) (R ₃₈ ), -C (R ₃₆ ) (R ₃₇ ) (OR ₃₉ ), -C (R ₀₁ ) (R ₀₂ ). ) (OR ₃₉ ) and the like.

In the formula, R _{36 to} R ₃₉ each independently represents an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or an alkenyl group. R ₃₆ and R ₃₇ may be bonded to each other to form a ring.

R _{01 and} R ₀₂ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group or an alkenyl group.

  The acid-decomposable group is preferably a cumyl ester group, an enol ester group, an acetal ester group, a tertiary alkyl ester group or the like. More preferably, it is a tertiary alkyl ester group.

In the resin of component (A), the repeating unit having an acid-decomposable group is preferably a repeating unit represented by the following general formula (AI).

In general formula (AI),
Xa ₁ represents a hydrogen atom, a methyl group, a trifluoromethyl group or a hydroxymethyl group.

T represents a single bond or a divalent linking group.
Rx _{1 to} Rx ₃ each independently represents an alkyl group (straight or branched) or a cycloalkyl group (monocyclic or polycyclic). At least two of Rx _{1 to} Rx ₃ may combine to form a cycloalkyl group (monocyclic or polycyclic).

Examples of the divalent linking group for T include an alkylene group, —COO—Rt— group, —O—Rt— group, and the like. In the formula, Rt represents an alkylene group or a cycloalkylene group.
T is preferably a single bond or a —COO—Rt— group. Rt is preferably an alkylene group having 1 to 5 carbon atoms, more preferably a —CH ₂ — group or a — (CH ₂ ) ₃ — group.
The alkyl group of Rx _{1 to} Rx ₃ is preferably an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, or a t-butyl group.

Examples of the cycloalkyl group represented by Rx _{1 to} Rx ₃ include monocyclic cycloalkyl groups such as cyclopentyl group and cyclohexyl group, polycyclic cycloalkyl groups such as norbornyl group, tetracyclodecanyl group, tetracyclododecanyl group, and adamantyl group. Groups are preferred.
Examples of the cycloalkyl group formed by combining at least two of Rx _{1 to} Rx ₃ include a monocyclic cycloalkyl group such as a cyclopentyl group and a cyclohexyl group, a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, A polycyclic cycloalkyl group such as an adamantyl group is preferred.

It is preferable that Rx ₁ is a methyl group or an ethyl group, and Rx ₂ and Rx ₃ are bonded to form the above-described cycloalkyl group.
The atomic group may further have a substituent, and examples thereof include an alkyl group, a cycloalkyl group, an alkoxy group, a hydroxyl group, and a cyano group.

  The acid-decomposable group is preferably a highly reactive protecting group.

As for the content rate of the repeating unit which has an acid-decomposable group, 20-50 mol% is preferable with respect to all the repeating units in resin (A), More preferably, it is 25-45 mol%.
Although the specific example of the repeating unit which has a preferable acid-decomposable group is shown below, this invention is not limited to this.

(In the above formula, Xa ₁ has the same meaning as Xa ₁ in the general formula (AI).)

(In the above formula, Xa ₁ has the same meaning as Xa ₁ in the general formula (AI).)

(In the above formula, Xa ₁ has the same meaning as Xa ₁ in the general formula (AI).)
The resin of component (A) may have a repeating unit containing a group capable of reacting with a functional group that crosslinks between the resins by heating in (a2) compound (C).
Here, the group capable of reacting may be a group capable of undergoing a crosslinking reaction with the functional group in the compound (C) by heating, and specifically, a hydroxyl group, a carboxyl group, an amino group, an amide group, a thiol group. And an active methylene group, preferably a hydroxyl group, a carboxyl group, an amide group, a thiol group and an active methylene group, more preferably a hydroxyl group and a carboxyl group.

Examples of the repeating unit (a2) include repeating units represented by the following general formula (D1).

In formula (D1),
D represents a group capable of reacting with a functional group that crosslinks between resins by heating in the compound (C), and specific examples thereof include the groups described above.
Xa _1, T is the same as _Xa 1, T in the general formula (AI).
Specific examples of the repeating unit (a2) having a group capable of reacting with a functional group that crosslinks between the resins by heating are given below, but the present invention is not limited thereto.
Note that in the formulas given below, R ^x has the same meaning as Xa ₁ in the general formula (D1).

  The content of the repeating unit (a2) is preferably from 1 to 50 mol%, more preferably from 3 to 40 mol%, still more preferably from 5 to 25 mol%, based on all repeating units in the resin (A). .

  The resin as the component (A) preferably further has (a3) a repeating unit having a lactone group.

Any lactone group can be used as long as it has a lactone structure, but it is preferably a 5- to 7-membered ring lactone structure, and forms a bicyclo structure or a spiro structure in the 5- to 7-membered ring lactone structure. The other ring structure is preferably condensed. It is more preferable to have a repeating unit having a lactone structure represented by any of the following general formulas (LC1-1) to (LC1-16). The lactone structure may be directly bonded to the main chain. Preferred lactone structures are (LC1-1), (LC1-4), (LC1-5), (LC1-6), (LC1-13), (LC1-14), and a specific lactone structure is used. This improves line edge roughness and development defects.

The lactone structure moiety may or may not have a substituent (Rb ₂ ). Preferred substituents (Rb ₂ ) include an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 4 to 7 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkoxycarbonyl group having 1 to 8 carbon atoms, and a carboxyl group. , Halogen atom, hydroxyl group, cyano group, acid-decomposable group and the like. More preferably, they are a C1-C4 alkyl group, a cyano group, and an acid-decomposable group. n ₂ represents an integer of 0-4. When n ₂ is 2 or more, a plurality of substituents (Rb ₂ ) may be the same or different, and a plurality of substituents (Rb ₂ ) may be bonded to form a ring. .
Examples of the repeating unit having a lactone structure represented by any one of the general formulas (LC1-1) to (LC1-16) include a repeating unit represented by the following general formula (AII).

In general formula (AII),
Rb ₀ represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 4 carbon atoms. Preferred substituents that the alkyl group represented by Rb ₀ may have include a hydroxyl group and a halogen atom. Examples of the halogen atom for Rb ₀ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Rb ₀ is preferably a hydrogen atom or a methyl group.

Ab represents a single bond, an alkylene group, a divalent linking group having a monocyclic or polycyclic alicyclic hydrocarbon structure, an ether group, an ester group, a carbonyl group, or a divalent linking group obtained by combining these. Preferably a single bond, -Ab ₁ -CO ₂ - is a divalent linking group represented by.

Ab ₁ is a linear, branched alkylene group, monocyclic or polycyclic cycloalkylene group, preferably a methylene group, an ethylene group, a cyclohexylene group, an adamantylene group or a norbornylene group. V represents a group having a structure represented by any one of the general formulas (LC1-1) to (LC1-16).

  The repeating unit having a lactone group usually has an optical isomer, but any optical isomer may be used. One optical isomer may be used alone, or a plurality of optical isomers may be mixed and used. When one kind of optical isomer is mainly used, the optical purity (ee) thereof is preferably 90 or more, more preferably 95 or more.

As for the content rate of the repeating unit which has a lactone group, 15-60 mol% is preferable with respect to all the repeating units in resin (A), More preferably, it is 20-50 mol%, More preferably, it is 30-50 mol%.
Specific examples of the repeating unit having a lactone group are listed below, but the present invention is not limited thereto.

Particularly preferred repeating units having a lactone group include the following repeating units. By selecting an optimal lactone group, the pattern profile and the density dependence become good.

The resin of component (A) preferably further has (a4) a repeating unit having a hydroxyl group or a cyano group. This improves the substrate adhesion and developer compatibility.
The repeating unit having a hydroxyl group or a cyano group is preferably a repeating unit having an alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group. The alicyclic hydrocarbon structure in the alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group is preferably an adamantyl group, a diamantyl group, or a norbornane group.

As the alicyclic hydrocarbon structure substituted with a preferred hydroxyl group or cyano group, partial structures represented by the following formulas (VIIa) to (VIId) are preferred.

In the general formulas (VIIa) to (VIIc), R ₂ c to R ₄ c each independently represents a hydrogen atom, a hydroxyl group, or a cyano group. However, at least one of R ₂ c to R ₄ c represents a hydroxyl group or a cyano group. Preferably, one or two of R ₂ c to R ₄ c are a hydroxyl group and the remaining is a hydrogen atom. In general formula (VIIa), more preferably, _two of R ₂ c to R ₄ c are hydroxyl groups and the remaining are hydrogen atoms.

Examples of the repeating unit having a partial structure represented by the formulas (VIIa) to (VIId) include the repeating units represented by the following general formulas (AIIa) to (AIId).

In the general formulas (AIIa) to (AIId), R ₁ c represents a hydrogen atom, a methyl group, a trifluoromethyl group, or a hydroxymethyl group. R ₂ c to R ₄ c are in the general formula (VIIa) ~ (VIIc), same meanings as R ₂ c~R ₄ c.

  The content of the repeating unit (a4) having an alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group is preferably from 5 to 40 mol%, more preferably from 5 to 30 mol, based on all repeating units in the resin (A). %, More preferably 10 to 25 mol%.

Specific examples of the repeating unit (a4) having a hydroxyl group or a cyano group are given below, but the present invention is not limited thereto.

The resin of component (A) preferably further has (a5) a repeating unit having an alkali-soluble group.
Examples of the alkali-soluble group include a carboxyl group, a sulfonamide group, a sulfonylimide group, a bisulsulfonylimide group, and an aliphatic alcohol (for example, hexafluoroisopropanol group) substituted with an electron-attracting group at the α-position. It is more preferable to have a repeating unit. By containing the repeating unit having an alkali-soluble group, the resolution in contact hole applications is increased. The repeating unit having an alkali-soluble group includes a repeating unit in which an alkali-soluble group is directly bonded to the main chain of the resin, such as a repeating unit of acrylic acid or methacrylic acid, or an alkali in the main chain of the resin through a linking group. Either a repeating unit to which a soluble group is bonded, or a polymerization initiator or chain transfer agent having an alkali-soluble group is used at the time of polymerization and introduced at the end of the polymer chain, and the linking group is monocyclic or polycyclic. It may have a cyclic hydrocarbon structure. Particularly preferred are repeating units of acrylic acid or methacrylic acid.

  As for the content rate of the repeating unit (a5) which has an alkali-soluble group, 0-20 mol% is preferable with respect to all the repeating units in resin (A), More preferably, it is 3-15 mol%, More preferably, it is 5-10 mol%. is there.

Specific examples of the repeating unit (a5) having an alkali-soluble group are shown below, but the present invention is not limited thereto.

The resin as component (A) may further have (a6) a repeating unit having an alicyclic hydrocarbon structure and not exhibiting acid decomposability. This can reduce elution of low molecular components from the resist film to the immersion liquid during immersion exposure, and is advantageous in terms of dry etching resistance. Examples of such a repeating unit include a repeating unit represented by the following general formula (III).

In general formula (III), R ₅ represents a hydrocarbon group having at least one cyclic structure and having neither a hydroxyl group nor a cyano group. Ra represents a hydrogen atom, an alkyl group, or a —CH ₂ —O—Ra ₂ group. In the formula, Ra ₂ represents a hydrogen atom, an alkyl group or an acyl group. The specific description of Ra is the same as the description of Ra in the general formula (I).

The cyclic structure possessed by R ₅ includes a monocyclic hydrocarbon group and a polycyclic hydrocarbon group. Examples of the monocyclic hydrocarbon group include cycloalkenyl having 3 to 12 carbon atoms such as cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group and the like, and cycloalkyl groups having 3 to 12 carbon atoms and cyclohexenyl group. Groups. Preferable monocyclic hydrocarbon groups are monocyclic hydrocarbon groups having 3 to 7 carbon atoms, and more preferable examples include a cyclopentyl group and a cyclohexyl group.

The polycyclic hydrocarbon group includes a ring assembly hydrocarbon group and a bridged cyclic hydrocarbon group, and examples of the ring assembly hydrocarbon group include a bicyclohexyl group and a perhydronaphthalenyl group. As the bridged cyclic hydrocarbon ring, for example, bicyclic such as pinane, bornane, norpinane, norbornane, bicyclooctane ring (bicyclo [2.2.2] octane ring, bicyclo [3.2.1] octane ring, etc.) Hydrocarbon rings and tricyclic hydrocarbon rings such as homobredan, adamantane, tricyclo [5.2.1.0 ^2,6 ] decane, tricyclo [4.3.1.1 ^2,5 ] undecane ring, tetracyclo [ 4.4.0.1 ^2,5 . 1 ^7,10 ] dodecane, and tetracyclic hydrocarbon rings such as perhydro-1,4-methano-5,8-methanonaphthalene ring. The bridged cyclic hydrocarbon ring includes a condensed cyclic hydrocarbon ring such as perhydronaphthalene (decalin), perhydroanthracene, perhydrophenanthrene, perhydroacenaphthene, perhydrofluorene, perhydroindene, perhydroindene. A condensed ring in which a plurality of 5- to 8-membered cycloalkane rings such as a phenalene ring are condensed is also included.

Preferred examples of the bridged cyclic hydrocarbon ring include a norbornyl group, an adamantyl group, a bicyclooctanyl group, a tricyclo [5,2,1,0 ^2,6 ] decanyl group, and the like. More preferable examples of the bridged cyclic hydrocarbon ring include a norbornyl group and an adamantyl group.

  These alicyclic hydrocarbon groups may have a substituent, and preferred substituents include a halogen atom, an alkyl group, a hydroxyl group protected with a protecting group, an amino group protected with a protecting group, and the like. It is done. Preferred halogen atoms include bromine, chlorine and fluorine atoms, and preferred alkyl groups include methyl, ethyl, butyl and t-butyl groups. The above alkyl group may further have a substituent, and the substituent which may further have a halogen atom, an alkyl group, a hydroxyl group protected with a protecting group, an amino protected with a protecting group The group can be mentioned.

  Examples of the protecting group include an alkyl group, a cycloalkyl group, an aralkyl group, a substituted methyl group, a substituted ethyl group, an alkoxycarbonyl group, and an aralkyloxycarbonyl group. Preferred alkyl groups include alkyl groups having 1 to 4 carbon atoms, preferred substituted methyl groups include methoxymethyl, methoxythiomethyl, benzyloxymethyl, t-butoxymethyl, 2-methoxyethoxymethyl groups, and preferred substituted ethyl groups. 1-ethoxyethyl, 1-methyl-1-methoxyethyl, preferred acyl groups include formyl, acetyl, propionyl, butyryl, isobutyryl, valeryl, pivaloyl groups, etc., aliphatic acyl groups having 1 to 6 carbon atoms, alkoxycarbonyl Examples of the group include an alkoxycarbonyl group having 1 to 4 carbon atoms.

The content of the repeating unit represented by the general formula (III) having neither a hydroxyl group nor a cyano group is preferably from 0 to 40 mol%, more preferably based on all repeating units in the resin (A). 0 to 20 mol%.
Specific examples of the repeating unit represented by the general formula (III) are shown below, but the present invention is not limited thereto.

In addition to the above repeating structural unit, the resin of component (A) includes dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and general required properties of resist, such as resolution, heat resistance, and sensitivity. Various repeating structural units can be included for the purpose of adjusting the above.

  Examples of such repeating structural units include, but are not limited to, repeating structural units corresponding to the following monomers.

Thereby, the performance required for the resin of component (A), in particular,
(1) Solubility in coating solvent,
(2) Film formability (glass transition point),
(3) Alkali developability,
(4) Membrane slip (hydrophobic, alkali-soluble group selection),
(5) Adhesion of unexposed part to substrate,
(6) Dry etching resistance,
Etc. can be finely adjusted.

  As such a monomer, for example, a compound having one addition polymerizable unsaturated bond selected from acrylic acid esters, methacrylic acid esters, acrylamides, methacrylamides, allyl compounds, vinyl ethers, vinyl esters, etc. Etc.

  In addition, any addition-polymerizable unsaturated compound that can be copolymerized with monomers corresponding to the above various repeating structural units may be copolymerized.

  In the resin of component (A), the molar ratio of each repeating structural unit is the resist dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and general resist performance required for resolving power and heat resistance. In order to adjust the sensitivity and the like, it is set as appropriate.

  When the positive resist composition of the present invention is for ArF exposure, the resin of component (A) preferably has no aromatic group from the viewpoint of transparency to ArF light.

  As the resin of component (A), preferably, all of the repeating units are composed of (meth) acrylate-based repeating units. In this case, all of the repeating units are methacrylate repeating units, all of the repeating units are acrylate repeating units, or all of the repeating units are methacrylate repeating units and acrylate repeating units. Although it can be used, the acrylate-based repeating unit is preferably 50 mol% or less of the total repeating units. More preferably, the (meth) acrylate repeating unit having an acid-decomposable group represented by the general formula (AI) is 20 to 50 mol%, the (meth) acrylate repeating unit having a lactone group is 20 to 50 mol%, It is a copolymer having 5 to 30 mol% of (meth) acrylate-based repeating units having an alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group, and further containing 0 to 20 mol% of other (meth) acrylate-based repeating units. .

  When the positive resist composition of the present invention is irradiated with KrF excimer laser light, electron beam, X-ray, or high energy light (EUV, etc.) having a wavelength of 50 nm or less, the resin of component (A) is represented by general formula (AI In addition to the repeating unit represented by), it is preferable to further have a hydroxystyrene-based repeating unit. More preferably, it has a hydroxystyrene-based repeating unit, a hydroxystyrene-based repeating unit protected with an acid-decomposable group, and an acid-decomposable repeating unit such as a (meth) acrylic acid tertiary alkyl ester.

  Preferred examples of the repeating unit having an acid-decomposable group include t-butoxycarbonyloxystyrene, 1-alkoxyethoxystyrene, a repeating unit of (meth) acrylic acid tertiary alkyl ester, and the like. The repeating unit by 2-adamantyl (meth) acrylate and dialkyl (1-adamantyl) methyl (meth) acrylate is more preferable.

  The resin of component (A) can be synthesized according to a conventional method (for example, radical polymerization). For example, as a general synthesis method, a monomer polymerization method in which a monomer species and an initiator are dissolved in a solvent and the polymerization is performed by heating, and a solution of the monomer species and the initiator is dropped into the heating solvent over 1 to 10 hours. The dropping polymerization method is added, and the dropping polymerization method is preferable. Examples of the reaction solvent include ethers such as tetrahydrofuran, 1,4-dioxane, diisopropyl ether, ketones such as methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate, amide solvents such as dimethylformamide and dimethylacetamide, Furthermore, the solvent which melt | dissolves the composition of this invention like the below-mentioned propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, and cyclohexanone is mentioned. More preferably, the polymerization is performed using the same solvent as the solvent used in the positive resist composition of the present invention. Thereby, the generation of particles during storage can be suppressed.

  The polymerization reaction is preferably performed in an inert gas atmosphere such as nitrogen or argon. As a polymerization initiator, a commercially available radical initiator (azo initiator, peroxide, etc.) is used to initiate the polymerization. As the radical initiator, an azo initiator is preferable, and an azo initiator having an ester group, a cyano group, or a carboxyl group is preferable. Preferred initiators include azobisisobutyronitrile, azobisdimethylvaleronitrile, dimethyl 2,2′-azobis (2-methylpropionate) and the like. If desired, an initiator is added or added in portions, and after completion of the reaction, it is put into a solvent and a desired polymer is recovered by a method such as powder or solid recovery. The concentration of the reaction is 5 to 50% by mass, preferably 10 to 30% by mass. The reaction temperature is usually 10 ° C to 150 ° C, preferably 30 ° C to 120 ° C, more preferably 60 ° C to 100 ° C.

  After completion of the reaction, the mixture is allowed to cool to room temperature and purified. Purification can be accomplished by a liquid-liquid extraction method that removes residual monomers and oligomer components by combining water and an appropriate solvent, and a purification method in a solution state such as ultrafiltration that extracts and removes only those having a specific molecular weight or less. , Reprecipitation method that removes residual monomer by coagulating resin in poor solvent by dripping resin solution into poor solvent and purification in solid state such as washing filtered resin slurry with poor solvent A normal method such as a method can be applied. For example, the resin is precipitated as a solid by contacting a solvent (poor solvent) in which the resin is hardly soluble or insoluble in a volume amount of 10 times or less, preferably 10 to 5 times that of the reaction solution.

  The solvent (precipitation or reprecipitation solvent) used in the precipitation or reprecipitation operation from the polymer solution may be a poor solvent for the polymer, and may be a hydrocarbon, halogenated hydrocarbon, nitro, depending on the type of polymer. A compound, ether, ketone, ester, carbonate, alcohol, carboxylic acid, water, a mixed solvent containing these solvents, and the like can be appropriately selected for use. Among these, as a precipitation or reprecipitation solvent, a solvent containing at least an alcohol (particularly methanol or the like) or water is preferable.

  The amount of the precipitation or reprecipitation solvent used can be appropriately selected in consideration of efficiency, yield, and the like, but generally 100 to 10000 parts by mass, preferably 200 to 2000 parts by mass with respect to 100 parts by mass of the polymer solution, More preferably, it is 300-1000 mass parts.

  The temperature for precipitation or reprecipitation can be appropriately selected in consideration of efficiency and operability, but is usually about 0 to 50 ° C., preferably around room temperature (for example, about 20 to 35 ° C.). The precipitation or reprecipitation operation can be performed by a known method such as a batch method or a continuous method using a conventional mixing vessel such as a stirring tank.

  The precipitated or re-precipitated polymer is usually subjected to conventional solid-liquid separation such as filtration and centrifugation, and dried before use. Filtration is performed using a solvent-resistant filter medium, preferably under pressure. Drying is performed at a temperature of about 30 to 100 ° C., preferably about 30 to 50 ° C. under normal pressure or reduced pressure (preferably under reduced pressure).

  The resin may be once deposited and separated, and then dissolved again in a solvent, and the resin may be brought into contact with a hardly soluble or insoluble solvent. That is, after the polymerization reaction is completed, a solvent in which the polymer is hardly soluble or insoluble is contacted to precipitate the resin (step a), the resin is separated from the solution (step b), and the resin solution A is dissolved again in the solvent. Preparation (step c), and then contacting the resin solution A with a solvent in which the resin is hardly soluble or insoluble in a volume amount less than 10 times that of the resin solution A (preferably a volume amount not more than 5 times). Alternatively, a method including precipitating a resin solid (step d) and separating the precipitated resin (step e) may be used.

  The weight average molecular weight of the component (A) resin is preferably 1,000 to 200,000, more preferably 2,000 to 20,000, and still more preferably 3,000 as a polystyrene-converted value by the GPC method. ˜15,000, particularly preferably 3,000 to 10,000. By setting the weight average molecular weight to 1,000 to 200,000, deterioration of heat resistance and dry etching resistance can be prevented, and deterioration of developability and film formation due to increase in viscosity can be prevented. it can.

  The dispersity (molecular weight distribution) is usually 1 to 3, preferably 1 to 2.6, more preferably 1 to 2, and particularly preferably 1.4 to 1.9. The smaller the molecular weight distribution, the better the resolution and the resist shape, and the smoother the side wall of the resist pattern, the better the roughness.

  In the positive resist composition of the present invention, the blending ratio of the component (A) resin in the entire composition is preferably 50 to 99 mass%, more preferably 60 to 98 mass%, based on the total solid content.

  In the present invention, the resin of component (A) may be used alone or in combination.

<(B) Compound that generates acid upon irradiation with actinic ray or radiation>
The resist composition of the present invention contains (B) a compound that generates an acid upon irradiation with actinic rays or radiation (hereinafter also referred to as “acid generator”).

  As an acid generator, photo-initiator of photocation polymerization, photo-initiator of photo-radical polymerization, photo-decoloring agent of dyes, photo-discoloring agent, or irradiation with actinic ray or radiation used for micro-resist etc. Known compounds that generate acids and mixtures thereof can be appropriately selected and used.

  Examples thereof include diazonium salts, phosphonium salts, sulfonium salts, iodonium salts, imide sulfonates, oxime sulfonates, diazodisulfones, disulfones, and o-nitrobenzyl sulfonates.

  Further, a group that generates an acid upon irradiation with these actinic rays or radiation, or a compound in which a compound is introduced into the main chain or side chain of the polymer, such as US Pat. No. 3,849,137, German Patent No. No. 3914407, JP-A 63-26653, JP-A 55-164824, JP-A 62-69263, JP-A 63-146038, JP-A 63-163452, The compounds described in JP-A-62-153853 and JP-A-63-146029 can be used.

Furthermore, compounds capable of generating an acid by light described in US Pat. No. 3,779,778, European Patent 126,712, etc. can also be used.
Preferred compounds among the acid generators include compounds represented by the following general formulas (ZI), (ZII), and (ZIII).

In the general formula (ZI),
R ₂₀₁ , R ₂₀₂ and R ₂₀₃ each independently represents an organic group.
The carbon number of the organic group as R ₂₀₁ , R ₂₀₂ and R ₂₀₃ is generally 1-30, preferably 1-20.
Two of R _{201 to} R ₂₀₃ may be bonded to form a ring structure, and the ring may contain an oxygen atom, a sulfur atom, an ester bond, an amide bond, or a carbonyl group. The two of the group formed by bonding of the R ₂₀₁ to R _203, there can be mentioned an alkylene group (e.g., butylene, pentylene).
Z ⁻ represents a non-nucleophilic anion.

Examples of the non-nucleophilic anion as Z ⁻ include a sulfonate anion, a carboxylate anion, a sulfonylimide anion, a bis (alkylsulfonyl) imide anion, and a tris (alkylsulfonyl) methyl anion.

  A non-nucleophilic anion is an anion that has an extremely low ability to cause a nucleophilic reaction, and is an anion that can suppress degradation over time due to an intramolecular nucleophilic reaction. This improves the temporal stability of the resist.

Examples of the sulfonate anion include an aliphatic sulfonate anion, an aromatic sulfonate anion, and a camphor sulfonate anion.
Examples of the carboxylate anion include an aliphatic carboxylate anion, an aromatic carboxylate anion, and an aralkylcarboxylate anion.

  The aliphatic moiety in the aliphatic sulfonate anion may be an alkyl group or a cycloalkyl group, preferably an alkyl group having 1 to 30 carbon atoms and a cycloalkyl group having 3 to 30 carbon atoms such as methyl. Group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, pentyl group, neopentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group , Tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, eicosyl group, cyclopropyl group, cyclopentyl group, cyclohexyl group, adamantyl group, norbornyl group, boronyl group and the like.

  The aromatic group in the aromatic sulfonate anion is preferably an aryl group having 6 to 14 carbon atoms, such as a phenyl group, a tolyl group, and a naphthyl group.

  The alkyl group, cycloalkyl group and aryl group in the aliphatic sulfonate anion and aromatic sulfonate anion may have a substituent. Examples of the substituent of the alkyl group, cycloalkyl group, and aryl group in the aliphatic sulfonate anion and aromatic sulfonate anion include, for example, a nitro group, a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom), carboxyl group , Hydroxyl group, amino group, cyano group, alkoxy group (preferably having 1 to 15 carbon atoms), cycloalkyl group (preferably having 3 to 15 carbon atoms), aryl group (preferably having 6 to 14 carbon atoms), alkoxycarbonyl group ( Preferably 2 to 7 carbon atoms, acyl group (preferably 2 to 12 carbon atoms), alkoxycarbonyloxy group (preferably 2 to 7 carbon atoms), alkylthio group (preferably 1 to 15 carbon atoms), alkylsulfonyl group (Preferably 1 to 15 carbon atoms), alkyliminosulfonyl group (preferably 2 to 15 carbon atoms), ant Ruoxysulfonyl group (preferably having 6 to 20 carbon atoms), alkylaryloxysulfonyl group (preferably having 7 to 20 carbon atoms), cycloalkylaryloxysulfonyl group (preferably having 10 to 20 carbon atoms), alkyloxyalkyloxy group (Preferably having 5 to 20 carbon atoms), a cycloalkylalkyloxyalkyloxy group (preferably having 8 to 20 carbon atoms), and the like. About the aryl group and ring structure which each group has, an alkyl group (preferably C1-C15) can further be mentioned as a substituent.

Examples of the aliphatic moiety in the aliphatic carboxylate anion include the same alkyl group and cycloalkyl group as in the aliphatic sulfonate anion.
Examples of the aromatic group in the aromatic carboxylate anion include the same aryl group as in the aromatic sulfonate anion.

  The aralkyl group in the aralkyl carboxylate anion is preferably an aralkyl group having 6 to 12 carbon atoms, such as a benzyl group, a phenethyl group, a naphthylmethyl group, a naphthylethyl group, and a naphthylmethyl group.

  The alkyl group, cycloalkyl group, aryl group and aralkyl group in the aliphatic carboxylate anion, aromatic carboxylate anion and aralkylcarboxylate anion may have a substituent. Examples of the substituent of the alkyl group, cycloalkyl group, aryl group and aralkyl group in the aliphatic carboxylate anion, aromatic carboxylate anion and aralkylcarboxylate anion include, for example, the same halogen atom and alkyl as in the aromatic sulfonate anion Group, cycloalkyl group, alkoxy group, alkylthio group and the like.

Examples of the sulfonylimide anion include saccharin anion.
The alkyl group in the bis (alkylsulfonyl) imide anion and tris (alkylsulfonyl) methyl anion is preferably an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, An isobutyl group, a sec-butyl group, a pentyl group, a neopentyl group, and the like can be given. Examples of substituents for these alkyl groups include halogen atoms, alkyl groups substituted with halogen atoms, alkoxy groups, alkylthio groups, alkyloxysulfonyl groups, aryloxysulfonyl groups, cycloalkylaryloxysulfonyl groups, and the like. Alkyl groups substituted with fluorine atoms are preferred.
Examples of other non-nucleophilic anions include fluorinated phosphorus, fluorinated boron, and fluorinated antimony.

Examples of the non-nucleophilic anion of Z ⁻ include an aliphatic sulfonate anion in which the α-position of the sulfonic acid is substituted with a fluorine atom, an aromatic sulfonate anion substituted with a fluorine atom or a group having a fluorine atom, and an alkyl group. A bis (alkylsulfonyl) imide anion substituted with a fluorine atom and a tris (alkylsulfonyl) methide anion wherein an alkyl group is substituted with a fluorine atom are preferred. More preferably, the non-nucleophilic anion is a perfluoroaliphatic sulfonic acid anion having 4 to 8 carbon atoms, a benzenesulfonic acid anion having a fluorine atom, a bis (alkylsulfonyl) imide anion having an alkyl group substituted with a fluorine atom, an alkyl A tris (alkylsulfonyl) methide anion in which the group is substituted with a fluorine atom. The bis (alkylsulfonyl) imide anion and the tris (alkylsulfonyl) methide anion may form a ring structure.

Examples of the organic group as R ₂₀₁ , R ₂₀₂ and R ₂₀₃ include the corresponding groups in the compounds (ZI-1), (ZI-2) and (ZI-3) described later.
In addition, the compound which has two or more structures represented by general formula (ZI) may be sufficient. For example, the general formula at least one of R ₂₀₁ to R ₂₀₃ of a compound represented by (ZI) is, at least one bond with structure of R ₂₀₁ to R ₂₀₃ of another compound represented by formula (ZI) It may be a compound.

More preferable (ZI) components include compounds (ZI-1), (ZI-2), and (ZI-3) described below.
The compound (ZI-1) is at least one of the aryl groups R ₂₀₁ to R ₂₀₃ in formula (ZI), arylsulfonium compounds, namely, compounds containing an arylsulfonium as a cation.

In the arylsulfonium compound, all of R _{201 to} R ₂₀₃ may be an aryl group, or a part of R _{201 to} R ₂₀₃ may be an aryl group with the remaining being an alkyl group or a cycloalkyl group.

  Examples of the arylsulfonium compound include triarylsulfonium compounds, diarylalkylsulfonium compounds, aryldialkylsulfonium compounds, diarylcycloalkylsulfonium compounds, and aryldicycloalkylsulfonium compounds.

  The aryl group of the arylsulfonium compound is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group. The aryl group may be an aryl group having a heterocyclic structure having an oxygen atom, a nitrogen atom, a sulfur atom or the like. Examples of the aryl group having a heterocyclic structure include a pyrrole residue (a group formed by losing one hydrogen atom from pyrrole) and a furan residue (a group formed by losing one hydrogen atom from furan). Groups), thiophene residues (groups formed by the loss of one hydrogen atom from thiophene), indole residues (groups formed by the loss of one hydrogen atom from indole), benzofuran residues ( A group formed by losing one hydrogen atom from benzofuran), a benzothiophene residue (a group formed by losing one hydrogen atom from benzothiophene), and the like. When the arylsulfonium compound has two or more aryl groups, the two or more aryl groups may be the same or different.

  The alkyl group or cycloalkyl group that the arylsulfonium compound has as necessary is preferably a linear or branched alkyl group having 1 to 15 carbon atoms and a cycloalkyl group having 3 to 15 carbon atoms, such as a methyl group, Examples thereof include an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, a t-butyl group, a cyclopropyl group, a cyclobutyl group, and a cyclohexyl group.

Aryl group, alkyl group of R ₂₀₁ to R _203, cycloalkyl group, an alkyl group (for example, 1 to 15 carbon atoms), a cycloalkyl group (for example, 3 to 15 carbon atoms), an aryl group (for example, 6 to 14 carbon atoms) , An alkoxy group (for example, having 1 to 15 carbon atoms), a halogen atom, a hydroxyl group, or a phenylthio group may be substituted. Preferred substituents are linear or branched alkyl groups having 1 to 12 carbon atoms, cycloalkyl groups having 3 to 12 carbon atoms, and linear, branched or cyclic alkoxy groups having 1 to 12 carbon atoms, more preferably carbon. These are an alkyl group having 1 to 4 carbon atoms and an alkoxy group having 1 to 4 carbon atoms. The substituent may be substituted with any one of the three R _{201 to} R ₂₀₃ , or may be substituted with all three. When R _{201 to} R ₂₀₃ are an aryl group, the substituent is preferably substituted at the p-position of the aryl group.

Next, the compound (ZI-2) will be described.
Compound (ZI-2) is a compound in which R _{201 to} R ₂₀₃ in formula (ZI) each independently represents an organic group having no aromatic ring. Here, the aromatic ring includes an aromatic ring containing a hetero atom.

The organic group having no aromatic ring as R ₂₀₁ to R ₂₀₃ generally has 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms.
R _{201 to} R ₂₀₃ are each independently preferably an alkyl group, a cycloalkyl group, an allyl group, or a vinyl group, more preferably a linear or branched 2-oxoalkyl group, 2-oxocycloalkyl group, alkoxy group. A carbonylmethyl group, particularly preferably a linear or branched 2-oxoalkyl group.

The alkyl group and cycloalkyl group of R ₂₀₁ to R _203, preferably a linear or branched alkyl group having 1 to 10 carbon atoms (e.g., methyl group, ethyl group, propyl group, butyl group, pentyl group), carbon Examples thereof include cycloalkyl groups of several 3 to 10 (cyclopentyl group, cyclohexyl group, norbornyl group). More preferred examples of the alkyl group include a 2-oxoalkyl group and an alkoxycarbonylmethyl group. More preferred examples of the cycloalkyl group include a 2-oxocycloalkyl group.

The 2-oxoalkyl group may be either linear or branched, and a group having> C = O at the 2-position of the above alkyl group is preferable.
The 2-oxocycloalkyl group is preferably a group having> C═O at the 2-position of the cycloalkyl group.

The alkoxy group in the alkoxycarbonylmethyl group is preferably an alkoxy group having 1 to 5 carbon atoms (methoxy group, ethoxy group, propoxy group, butoxy group, pentoxy group).
R _{201 to} R ₂₀₃ may be further substituted with a halogen atom, an alkoxy group (for example, having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, or a nitro group.

  Next, the compound (ZI-3) will be described.

The compound (ZI-3) is a compound represented by the following general formula (ZI-3), and is a compound having a phenacylsulfonium salt structure.

In General Formula (ZI-3), R _{1c to} R _5c each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, or a halogen atom. R _6c and R _7c each independently represents a hydrogen atom, an alkyl group or a cycloalkyl group. R _x and R _y each independently represents an alkyl group, a cycloalkyl group, an allyl group or a vinyl group.

Any two or more of R _{1c to} R _5c , R _6c and R _7c , and R _x and R _y may be bonded to each other to form a ring structure, and this ring structure includes an oxygen atom and a sulfur atom. , An ester bond and an amide bond may be included. Examples of the group formed by combining any two or more of R _{1c to} R _5c , R _6c and R _7c , and R _x and R _y include a butylene group and a pentylene group.
Zc ⁻ represents a non-nucleophilic anion, and examples thereof include the same non-nucleophilic anion as Z ^{− in} formula (ZI).

The alkyl group as R _{1c to} R _7c may be either linear or branched, for example, an alkyl group having 1 to 20 carbon atoms, preferably a linear or branched alkyl group having 1 to 12 carbon atoms ( Examples thereof include a methyl group, an ethyl group, a linear or branched propyl group, a linear or branched butyl group, and a linear or branched pentyl group. Examples of the cycloalkyl group include cyclohexane having 3 to 8 carbon atoms. An alkyl group (for example, a cyclopentyl group, a cyclohexyl group) can be mentioned.

The alkoxy group as R _{1c to} R _{5c may} be linear, branched or cyclic, for example, an alkoxy group having 1 to 10 carbon atoms, preferably a linear or branched alkoxy group having 1 to 5 carbon atoms. (For example, methoxy group, ethoxy group, linear or branched propoxy group, linear or branched butoxy group, linear or branched pentoxy group), C3-C8 cyclic alkoxy group (for example, cyclopentyloxy group, cyclohexyloxy group) ).

Preferably, any of R _{1c to} R _5c is a linear or branched alkyl group, a cycloalkyl group, or a linear, branched or cyclic alkoxy group, and more preferably the sum of the carbon number of R _{1c to} R _5c. Is 2-15. Thereby, solvent solubility improves more and generation | occurrence | production of a particle is suppressed at the time of a preservation | save.

_Examples of the alkyl group and cycloalkyl group as R _x and R _y include the same alkyl group and cycloalkyl group as in R _{1c to} R _7c , such as a 2-oxoalkyl group, a 2-oxocycloalkyl group, an alkoxy group. A carbonylmethyl group is more preferred.

Examples of the 2-oxoalkyl group and 2-oxocycloalkyl group include a group having> C═O at the 2-position of the alkyl group or cycloalkyl group as R _{1c to} R _7c .
Examples of the alkoxy group in the alkoxycarbonylmethyl group include the same alkoxy groups as in R _{1c to} R _5c .

R _x and R _y are preferably an alkyl group or cycloalkyl group having 4 or more carbon atoms, more preferably 6 or more, and still more preferably 8 or more alkyl groups or cycloalkyl groups.

Next, general formulas (ZII) and (ZIII) will be described.
In formula (ZII), (ZIII), R 204 ~R 207 each independently represents an aryl group, an alkyl group or a cycloalkyl group.

Phenyl group and a naphthyl group are preferred as the aryl group of R ₂₀₄ to R _207, more preferably a phenyl group. Aryl group R ₂₀₄ to R ₂₀₇ represents an oxygen atom, a nitrogen atom, may be an aryl group having a heterocyclic structure having a sulfur atom and the like. Examples of the aryl group having a heterocyclic structure include a pyrrole residue (a group formed by losing one hydrogen atom from pyrrole) and a furan residue (a group formed by losing one hydrogen atom from furan). Groups), thiophene residues (groups formed by the loss of one hydrogen atom from thiophene), indole residues (groups formed by the loss of one hydrogen atom from indole), benzofuran residues ( A group formed by losing one hydrogen atom from benzofuran), a benzothiophene residue (a group formed by losing one hydrogen atom from benzothiophene), and the like.

The alkyl group and cycloalkyl group in R ₂₀₄ to R _207, preferably a linear or branched alkyl group having 1 to 10 carbon atoms (e.g., methyl group, ethyl group, propyl group, butyl group, pentyl group), carbon Examples thereof include cycloalkyl groups of several 3 to 10 (cyclopentyl group, cyclohexyl group, norbornyl group).

Aryl group, alkyl group of R ₂₀₄ to R _207, cycloalkyl groups may have a substituent. Aryl group, alkyl group of R ₂₀₄ to R _207, the cycloalkyl group substituent which may be possessed by, for example, an alkyl group (for example, 1 to 15 carbon atoms), a cycloalkyl group (for example, 3 to 15 carbon atoms ), An aryl group (for example, having 6 to 15 carbon atoms), an alkoxy group (for example, having 1 to 15 carbon atoms), a halogen atom, a hydroxyl group, and a phenylthio group.
Z ⁻ represents a non-nucleophilic anion, and examples thereof include the same as the non-nucleophilic anion of Z ^{− in} formula (ZI).
Examples of the acid generator further include compounds represented by the following general formulas (ZIV), (ZV), and (ZVI).

In general formulas (ZIV) to (ZVI), Ar ₃ and Ar ₄ each independently represents an aryl group.
R ₂₀₈ , R ₂₀₉ and R ₂₁₀ each independently represents an alkyl group, a cycloalkyl group or an aryl group. A represents an alkylene group, an alkenylene group or an arylene group.
Among the acid generators, compounds represented by the general formulas (ZI) to (ZIII) are more preferable.

Further, the acid generator is preferably a compound that generates an acid having one sulfonic acid group or imide group, more preferably a compound that generates monovalent perfluoroalkanesulfonic acid, or a monovalent fluorine atom or fluorine atom. A compound that generates an aromatic sulfonic acid substituted with a group containing fluorinated acid, or a compound that generates a monovalent fluorine atom or imide acid substituted with a group containing a fluorine atom, and even more preferably, It is a sulfonium salt of a substituted alkanesulfonic acid, a fluorine-substituted benzenesulfonic acid, a fluorine-substituted imide acid or a fluorine-substituted methide acid. The acid generator that can be used is particularly preferably a fluorinated substituted alkane sulfonic acid, a fluorinated substituted benzene sulfonic acid or a fluorinated substituted imido acid whose pKa of the generated acid is pKa = -1 or less, and the sensitivity is improved. .
Among acid generators, particularly preferred examples are listed below, but the present invention is not limited thereto.

An acid generator can be used individually by 1 type or in combination of 2 or more types.
The content of the acid generator in the positive photosensitive composition is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass, based on the total solid content of the positive photosensitive composition. More preferably, it is 1-7 mass%.

<(C) Compound having a functional group that crosslinks between resins by heating>
The resist composition of the present invention contains (C) a compound having a functional group that crosslinks between resins by heating.

The compound (C) is a compound having a functional group capable of reacting with a hydroxyl group, a carboxyl group or the like which can be contained in the resist composition of the present invention by heating to form an interpolymer crosslink. Specifically, the functional group is heated to form the repeating unit (a2) in the resin of the component (A) or the hydroxyl group, carboxyl group, amino group, amide group, thiol contained in the compound (D) described later. It is considered that pattern curing after pattern formation becomes possible by reacting with a reactive group such as a group or an active methylene group to form an interpolymer crosslink. Inclusion of the compound is expected to improve pattern curability.
As an example of the compound (C), a compound represented by the following general formula (C1) can be given.

In formula (C1),
C represents a functional group that crosslinks between the resins by heating.
Q ^C represents a single bond or ^{n C} valent organic structure.
n ^C represents an integer of 1 or more, preferably 2 to 10, and more preferably 2 to 6. When n ^C is 2 or more, the plurality of C may be the same or different, and a plurality of C may be bonded to form a ring.

  Specific examples of C include a blocked isocyanate group and a blocked thioisocyanate group (hereinafter also referred to as “block (thio) isocyanate group”).

A blocked (thio) isocyanate group is obtained by reacting a (thio) isocyanate group (—NCO or —NCS) with a compound having a hydrogen atom capable of reacting with a (thio) isocyanate group (usually called a blocking agent). Thus, the (thio) isocyanate group is protected. The introduced protective group (those with a hydrogen atom removed from the blocking agent) is usually called a blocking group.
As the blocking agent, known blocking agents described in, for example, JP-A Nos. 5-186564 and 2002-275231 can be used.

Specifically, compounds having a phenolic hydroxyl group such as phenol, naphthol, cresol, xylenol, halogen-substituted phenol; oxime compounds such as acetoxime, formaldoxime, cyclohexaneoxime, methylethylketoxime; pyrazole, methylpyrazole, dimethylpyrazole, etc. Compounds having a pyrazole structure of: alcohol compounds such as methanol, ethanol, propanol, butanol, cyclohexanol, ethylene glycol monoalkyl ether, propylene glycol monoalkyl ether, alkyl lactate; activity of ethyl acetoacetate, diethyl malonate, acetylacetone, etc. Compound having methylene; mercaptan compound such as alkyl mercaptan and aryl mercaptan; α-lactam, β-lactam Beam, .gamma.-lactam, lactam compounds such as δ- lactams, other imide compounds, imidazole compounds, primary amines, secondary amines, and the like.
In one embodiment, the structure of the block (thio) isocyanate group is represented by the following general formula (1).

In general formula (1),
X represents an oxygen or sulfur atom.
R _bl represents a monovalent group in which the hydrogen atom is removed from the above-mentioned blocking group, that is, a compound having a hydrogen atom capable of reacting with the (thio) isocyanate group (blocking agent). When there are a plurality of blocked (thio) isocyanate groups in compound C, the plurality of R _bl may be the same or different. A plurality of R _bl may combine to form a ring structure.
* Represents a binding site.

  A preferred blocking group in the present invention is any of a group derived from a compound having a phenolic hydroxyl group, an oxime compound, or a compound having a pyrazole structure.

If Q ^C is the ^{n C-valent} organic structure, chain or cyclic alkyl structure (2 to 20 carbon atoms is preferred) or an aryl structure (having 6 to 30 carbon atoms is preferred), or their ethers, esters, amides, Sulfonamide and the like are preferable.

If Q ^C is the n ^C-valent organic structure, chain or cyclic aliphatic saturated hydrocarbon (preferably having 2 to 20 carbon atoms) n ^C valent organic group obtained by removing n ^C hydrogen atoms from, or aromatic family hydrocarbon (preferably having 6 to 30 carbon atoms) n ^C valent organic group obtained by removing n ^C hydrogen atoms from, or their ethers, esters, amides, and sulfonic amides are preferred.

Preferably as the Q ^C is an organic structure having no absorption with respect to ArF laser (193 nm), saturated hydrocarbon structures and these ether chain or cyclic, ester, amide, sulfonamide preferred. A cyclic saturated hydrocarbon structure is preferable from the viewpoint of etching resistance and pattern dimension control, and a chain-like saturated hydrocarbon structure is preferable from the viewpoint of high contrast. The Q ^C may have a structure having both chain alkyl structure forming a cyclic alkyl structure. In this case, the above performance can be balanced, which is a preferable mode.

  Specific examples of the chain-like saturated hydrocarbon structure include n-valent methane, ethane, propane, i-propane, butane, s-butane, t-butane, pentane, hexane, and decane in which n hydrogen atoms are removed. Structures and their ethers, esters, amides, sulfonamides are mentioned.

  Specific examples of the cyclic saturated hydrocarbon structure include an n-valent structure obtained by removing n hydrogen atoms from a monocyclic alkane structure such as cyclobutane, cyclopentane, cyclohexane, and cyclooctane, norbornane, isobornane, tricyclodecane, tetra Examples thereof include n-valent structures in which n hydrogen atoms are removed from a polycyclic alkane structure such as cyclododecane and adamantane, and ethers, esters, amides and sulfonamides thereof.

When Q ^C is an aromatic ring structure is less condensed aromatic structures and their ethers absorption against ArF laser (193 nm), an ester, amide, sulfonamide preferred. Examples of such a structure include an n-valent structure in which n hydrogen atoms are removed from naphthalene, anthracene, phenanthrene, naphthacene, pyrene, and perylene. Also, Q ^C may be a structure having both of condensed aromatic structures and chain or cyclic alkyl structure.

Specific examples of the compound (C) having a functional group that crosslinks between resins by heating are listed below, but the present invention is not limited thereto.

A compound (C) can be used individually by 1 type or in combination of 2 or more types.
The content of the compound (C) in the resist composition is preferably 0.1 to 20% by mass, more preferably 0.5 to 15% by mass, and still more preferably based on the total solid content of the positive resist composition. Is 1-10 mass%.

<(D) Compound containing a group capable of reacting with a functional group that crosslinks between resins by heating in compound (C)>
The resist composition of the present invention may contain a compound containing a group capable of reacting with a functional group that crosslinks between resins by heating in (D) compound (C). It is considered that the compound (D) reacts with a functional group in the compound (C) by heating to form an interpolymer crosslink, and pattern curing after pattern formation becomes possible.

  Here, the group capable of reacting may be a group capable of undergoing a crosslinking reaction with the functional group in the compound (C) by heating, and specifically, a hydroxyl group, a carboxyl group, an amino group, an amide group, a thiol group. And an active methylene group, preferably a hydroxyl group, a carboxyl group, an amide group, a thiol group and an active methylene group, more preferably a hydroxyl group and a carboxyl group.

Examples of the compound include a compound represented by the following general formula (D2).

In formula (D2),
D represents a group capable of reacting with a functional group that crosslinks between resins by heating in the compound (C), and specific examples thereof include the groups described above.
Q ^D represents a single bond or ^{n D} valent organic structure, the same meaning as ^{Q C} in the general formula (C1).
n ^D represents an integer of 1 or more, preferably 2 to 10, and more preferably 2 to 6. When n ^D is an integer of 2 or more, the plurality of D may be the same or different.

Although the specific example of a compound (D) is illustrated below, this invention is not limited to these.

The compound (D) having a group capable of reacting with an active functional group generated by heating can be used alone or in combination of two or more.
The content of the compound (D) having a group capable of reacting with an active functional group generated by heating in the resist composition is 0.1 to 20% by mass based on the total solid content of the positive photosensitive composition. Is preferable, more preferably 0.5 to 10% by mass, and still more preferably 1 to 5% by mass.

The mold resist composition of the present invention preferably contains a basic compound in order to reduce changes in performance over time from exposure to heating.
Preferred examples of the basic compound include compounds having structures represented by the following formulas (A) to (E).

In general formula (A), R ²⁰⁰ , R ²⁰¹ and R ²⁰² may be the same or different, and are a hydrogen atom, an alkyl group (preferably having 1 to 20 carbon atoms), a cycloalkyl group (preferably having 3 to 20 carbon atoms). ) Or an aryl group (having 6 to 20 carbon atoms), wherein R ²⁰¹ and R ²⁰² may be bonded to each other to form a ring.

In general formula (E), R ²⁰³ , R ²⁰⁴ , R ²⁰⁵ and R ²⁰⁶ may be the same or different and each represents an alkyl group having 1 to 20 carbon atoms.
The alkyl group, cycloalkyl group, and aryl group may have a substituent, and the substituent is preferably an amino group, a hydroxy group, or a cyano group.
The alkyl groups in the general formulas (A) and (E) are more preferably unsubstituted.

  Preferred compounds include guanidine, aminopyrrolidine, pyrazole, pyrazoline, piperazine, aminomorpholine, aminoalkylmorpholine, piperidine and the like, and more preferred compounds include imidazole structure, diazabicyclo structure, onium hydroxide structure, onium carboxylate Examples thereof include a compound having a structure, a trialkylamine structure, an aniline structure or a pyridine structure, an alkylamine derivative having a hydroxyl group and / or an ether bond, and an aniline derivative having a hydroxyl group and / or an ether bond.

  Examples of the compound having an imidazole structure include imidazole, 2,4,5-triphenylimidazole, benzimidazole, and 2-phenylbenzimidazole. Examples of the compound having a diazabicyclo structure include 1,4-diazabicyclo [2,2,2] octane, 1,5-diazabicyclo [4,3,0] non-5-ene, and 1,8-diazabicyclo [5,4,0. ] Undecar 7-ene etc. are mentioned. Examples of the compound having an onium hydroxide structure include tetrabutylammonium hydroxide, triarylsulfonium hydroxide, phenacylsulfonium hydroxide, sulfonium hydroxide having a 2-oxoalkyl group, specifically, triphenylsulfonium hydroxide, tris ( and t-butylphenyl) sulfonium hydroxide, bis (t-butylphenyl) iodonium hydroxide, phenacylthiophenium hydroxide, 2-oxopropylthiophenium hydroxide, and the like. As the compound having an onium carboxylate structure, an anion portion of the compound having an onium hydroxide structure is converted to a carboxylate, and examples thereof include acetate, adamantane-1-carboxylate, and perfluoroalkylcarboxylate. Examples of the compound having a trialkylamine structure include tri (n-butyl) amine and tri (n-octyl) amine. Examples of the aniline compound include 2,6-diisopropylaniline, N, N-dimethylaniline, N, N-dibutylaniline, N, N-dihexylaniline and the like. Examples of the alkylamine derivative having a hydroxyl group and / or an ether bond include ethanolamine, diethanolamine, triethanolamine, N-phenyldiethanolamine, and tris (methoxyethoxyethyl) amine. Examples of aniline derivatives having a hydroxyl group and / or an ether bond include N, N-bis (hydroxyethyl) aniline.

  Preferred examples of the basic compound further include an amine compound having a phenoxy group, an ammonium salt compound having a phenoxy group, an amine compound having a sulfonic acid ester group, and an ammonium salt compound having a sulfonic acid ester group.

As the amine compound, a primary, secondary or tertiary amine compound can be used, and an amine compound in which at least one alkyl group is bonded to a nitrogen atom is preferable. The amine compound is more preferably a tertiary amine compound. As long as at least one alkyl group (preferably having 1 to 20 carbon atoms) is bonded to a nitrogen atom, the amine compound has an cycloalkyl group (preferably having 3 to 20 carbon atoms) or an aryl group (preferably having 3 to 20 carbon atoms). Preferably C6-C12) may be bonded to a nitrogen atom. The amine compound preferably has an oxygen atom in the alkyl chain and an oxyalkylene group is formed. The number of oxyalkylene groups is one or more in the molecule, preferably 3 to 9, and more preferably 4 to 6. Among the oxyalkylene groups, an oxyethylene group (—CH ₂ CH ₂ O—) or an oxypropylene group (—CH (CH ₃ ) CH ₂ O— or —CH ₂ CH ₂ CH ₂ O—) is preferable, and more preferably oxy Ethylene group.

As the ammonium salt compound, a primary, secondary, tertiary, or quaternary ammonium salt compound can be used, and an ammonium salt compound in which at least one alkyl group is bonded to a nitrogen atom is preferable. As long as at least one alkyl group (preferably having 1 to 20 carbon atoms) is bonded to a nitrogen atom, the ammonium salt compound has a cycloalkyl group (preferably having 3 to 20 carbon atoms) or an aryl group in addition to the alkyl group. (Preferably having 6 to 12 carbon atoms) may be bonded to a nitrogen atom. The ammonium salt compound preferably has an oxygen atom in the alkyl chain and an oxyalkylene group is formed. The number of oxyalkylene groups is one or more in the molecule, preferably 3 to 9, and more preferably 4 to 6. Among the oxyalkylene groups, an oxyethylene group (—CH ₂ CH ₂ O—) or an oxypropylene group (—CH (CH ₃ ) CH ₂ O— or —CH ₂ CH ₂ CH ₂ O—) is preferable, and more preferably oxy Ethylene group.

  Examples of the anion of the ammonium salt compound include halogen atoms, sulfonates, borates, and phosphates. Among them, halogen atoms and sulfonates are preferable. As the halogen atom, chloride, bromide, and iodide are particularly preferable. As the sulfonate, an organic sulfonate having 1 to 20 carbon atoms is particularly preferable. Examples of the organic sulfonate include alkyl sulfonates having 1 to 20 carbon atoms and aryl sulfonates. The alkyl group of the alkyl sulfonate may have a substituent, and examples of the substituent include fluorine, chlorine, bromine, alkoxy groups, acyl groups, and aryl groups. Specific examples of the alkyl sulfonate include methane sulfonate, ethane sulfonate, butane sulfonate, hexane sulfonate, octane sulfonate, benzyl sulfonate, trifluoromethane sulfonate, pentafluoroethane sulfonate, and nonafluorobutane sulfonate. Examples of the aryl group of the aryl sulfonate include a benzene ring, a naphthalene ring, and an anthracene ring. The benzene ring, naphthalene ring and anthracene ring may have a substituent, and the substituent is preferably a linear or branched alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms. Specific examples of the linear or branched alkyl group and cycloalkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, i-butyl, t-butyl, n-hexyl, cyclohexyl and the like. Examples of the other substituent include an alkoxy group having 1 to 6 carbon atoms, a halogen atom, cyano, nitro, an acyl group, and an acyloxy group.

  The amine compound having a phenoxy group and the ammonium salt compound having a phenoxy group are those having a phenoxy group at the terminal opposite to the nitrogen atom of the alkyl group of the amine compound or ammonium salt compound. The phenoxy group may have a substituent. Examples of the substituent of the phenoxy group include an alkyl group, an alkoxy group, a halogen atom, a cyano group, a nitro group, a carboxyl group, a carboxylic acid ester group, a sulfonic acid ester group, an aryl group, an aralkyl group, an acyloxy group, and an aryloxy group. Etc. The substitution position of the substituent may be any of the 2-6 positions. The number of substituents may be any in the range of 1 to 5.

It is preferable to have at least one oxyalkylene group between the phenoxy group and the nitrogen atom. The number of oxyalkylene groups is one or more in the molecule, preferably 3 to 9, and more preferably 4 to 6. Among the oxyalkylene groups, an oxyethylene group (—CH ₂ CH ₂ O—) or an oxypropylene group (—CH (CH ₃ ) CH ₂ O— or —CH ₂ CH ₂ CH ₂ O—) is preferable, and more preferably oxy Ethylene group.

  In the amine compound having a sulfonic acid ester group and the ammonium salt compound having a sulfonic acid ester group, the sulfonic acid ester group may be any of alkyl sulfonic acid ester, cycloalkyl group sulfonic acid ester, and aryl sulfonic acid ester. In the case of an alkyl sulfonate ester, the alkyl group has 1 to 20 carbon atoms. In the case of a cycloalkyl sulfonate ester, the cycloalkyl group has 3 to 20 carbon atoms. In the case of an aryl sulfonate ester, the aryl group has 6 carbon atoms. ~ 12 are preferred. Alkyl sulfonic acid ester, cycloalkyl sulfonic acid ester, and aryl sulfonic acid ester may have a substituent. Examples of the substituent include a halogen atom, a cyano group, a nitro group, a carboxyl group, a carboxylic acid ester group, and a sulfonic acid. An ester group is preferred.

It is preferable to have at least one oxyalkylene group between the sulfonate group and the nitrogen atom. The number of oxyalkylene groups is one or more in the molecule, preferably 3 to 9, and more preferably 4 to 6. Among the oxyalkylene groups, an oxyethylene group (—CH ₂ CH ₂ O—) or an oxypropylene group (—CH (CH ₃ ) CH ₂ O— or —CH ₂ CH ₂ CH ₂ O—) is preferable, and more preferably oxy Ethylene group.

These basic compounds are used alone or in combination of two or more.
The content rate of a basic compound is 0.001-10 mass% normally based on solid content of a positive resist composition, Preferably it is 0.01-5 mass%.

  The use ratio of the acid generator and the basic compound in the composition is preferably acid generator / basic compound (molar ratio) = 2.5 to 300. In other words, the molar ratio is preferably 2.5 or more from the viewpoint of sensitivity and resolution, and is preferably 300 or less from the viewpoint of suppressing the reduction in resolution due to the thickening of the resist pattern over time until post-exposure heat treatment. The acid generator / basic compound (molar ratio) is more preferably 5.0 to 200, still more preferably 7.0 to 150.

  The positive resist composition of the present invention preferably further contains a surfactant, and a fluorine-based and / or silicon-based surfactant (fluorine-based surfactant, silicon-based surfactant, fluorine atom and silicon atom It is more preferable to contain either one or two or more surfactants having both.

  When the positive resist composition of the present invention contains the above-described surfactant, a resist pattern with good adhesion and low development defects can be obtained with good sensitivity and resolution when using an exposure light source of 250 nm or less, particularly 220 nm or less. It becomes possible.

  Examples of the fluorine-based and / or silicon-based surfactant include, for example, JP-A No. 62-36663, JP-A No. 61-226746, JP-A No. 61-226745, JP-A No. 62-170950, JP 63-34540 A, JP 7-230165 A, JP 8-62834 A, JP 9-54432 A, JP 9-5988 A, JP 2002-277862 A, US Patent Nos. 5,405,720, 5,360,692, 5,529,881, 5,296,330, 5,436,098, 5,576,143, 5,294,511, 5,824,451 Surfactant can be mentioned, The following commercially available surfactant can also be used as it is.

  Examples of commercially available surfactants that can be used include F-top EF301, EF303 (manufactured by Shin-Akita Kasei Co., Ltd.), Florard FC430, 431, 4430 (manufactured by Sumitomo 3M Co., Ltd.), MegaFuck F171, F173, F176, F189 , F113, F110, F177, F120, R08 (Dainippon Ink Chemical Co., Ltd.), Surflon S-382, SC101, 102, 103, 104, 105, 106 (Asahi Glass Co., Ltd.), Troisol S-366 (Manufactured by Troy Chemical Co., Ltd.), GF-300, GF-150 (manufactured by Toagosei Chemical Co., Ltd.), Surflon S-393 (manufactured by Seimi Chemical Co., Ltd.), F-top EF121, EF122A, EF122B, RF122C, EF125M , EF135M, EF351, 352, EF801, EF802, EF 01 (manufactured by Gemco), PF636, PF656, PF6320, PF6520 (manufactured by OMNOVA), FTX-204G, 208G, 218G, 230G, 204D, 208D, 212D, 218D, 222D (manufactured by Neos) Fluorine type surfactant or silicon type surfactant can be mentioned. Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) can also be used as a silicon-based surfactant.

  In addition to the known surfactants described above, the surfactant is derived from a fluoroaliphatic compound produced by a telomerization method (also called telomer method) or an oligomerization method (also called oligomer method). A surfactant using a polymer having a fluoroaliphatic group can be used. The fluoroaliphatic compound can be synthesized by the method described in JP-A-2002-90991.

  As the polymer having a fluoroaliphatic group, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate and / or (poly (oxyalkylene)) methacrylate is preferable and distributed irregularly. Or may be block copolymerized. Examples of the poly (oxyalkylene) group include a poly (oxyethylene) group, a poly (oxypropylene) group, a poly (oxybutylene) group, and the like, and a poly (oxyethylene, oxypropylene, and oxyethylene group). A unit having different chain lengths in the same chain length, such as a block link) or poly (block link of oxyethylene and oxypropylene) may be used. Furthermore, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate (or methacrylate) is not only a binary copolymer but also a monomer having two or more different fluoroaliphatic groups, Further, it may be a ternary or higher copolymer obtained by simultaneously copolymerizing two or more different (poly (oxyalkylene)) acrylates (or methacrylates).

Examples of commercially available surfactants include Megafac F178, F-470, F-473, F-475, F-476, and F-472 (Dainippon Ink Chemical Co., Ltd.). Further, a copolymer of an acrylate (or methacrylate) having a C ₆ F ₁₃ group and (poly (oxyalkylene)) acrylate (or methacrylate), an acrylate (or methacrylate) having a C ₃ F ₇ group and (poly (oxy) And a copolymer of (ethylene)) acrylate (or methacrylate) and (poly (oxypropylene)) acrylate (or methacrylate).

  In the present invention, other surfactants other than fluorine-based and / or silicon-based surfactants can also be used. Specifically, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, polyoxyethylene alkyl ethers such as polyoxyethylene oleyl ether, polyoxyethylene octylphenol ether, polyoxyethylene nonylphenol ether, etc. Sorbitans such as polyoxyethylene alkyl aryl ethers, polyoxyethylene / polyoxypropylene block copolymers, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, sorbitan tristearate Fatty acid esters, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopa Mite - DOO, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, may be mentioned polyoxyethylene sorbitan tristearate nonionic surfactants of polyoxyethylene sorbitan fatty acid esters such as such.

  These surfactants may be used alone or in several combinations.

  The amount of the surfactant used is preferably 0.0001 to 2% by mass, more preferably 0.001 to 1% by mass, based on the total amount of the positive resist composition (excluding the solvent).

  Solvents that can be used when preparing the positive resist composition by dissolving the above components include, for example, alkylene glycol monoalkyl ether carboxylate, alkylene glycol monoalkyl ether, alkyl lactate ester, and alkyl alkoxypropionate. And organic solvents such as cyclic lactones (preferably having 4 to 10 carbon atoms), monoketone compounds which may contain rings (preferably having 4 to 10 carbon atoms), alkylene carbonates, alkyl alkoxyacetates and alkyl pyruvates. it can.

  Examples of the alkylene glycol monoalkyl ether carboxylate include propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, propylene glycol monomethyl ether propionate, propylene glycol monoethyl Preferred examples include ether propionate, ethylene glycol monomethyl ether acetate, and ethylene glycol monoethyl ether acetate.

  Preferred examples of the alkylene glycol monoalkyl ether include propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, ethylene glycol monomethyl ether, and ethylene glycol monoethyl ether.

  Preferred examples of the alkyl lactate include methyl lactate, ethyl lactate, propyl lactate and butyl lactate.

  Preferable examples of the alkyl alkoxypropionate include ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, methyl 3-ethoxypropionate, and ethyl 3-methoxypropionate.

  Examples of the cyclic lactone include β-propiolactone, β-butyrolactone, γ-butyrolactone, α-methyl-γ-butyrolactone, β-methyl-γ-butyrolactone, γ-valerolactone, γ-caprolactone, and γ-octano. Preferred are iclactone and α-hydroxy-γ-butyrolactone.

  Examples of the monoketone compound which may contain a ring include 2-butanone, 3-methylbutanone, pinacolone, 2-pentanone, 3-pentanone, 3-methyl-2-pentanone, 4-methyl-2-pentanone, 2 -Methyl-3-pentanone, 4,4-dimethyl-2-pentanone, 2,4-dimethyl-3-pentanone, 2,2,4,4-tetramethyl-3-pentanone, 2-hexanone, 3-hexanone, 5-methyl-3-hexanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-methyl-3-heptanone, 5-methyl-3-heptanone, 2,6-dimethyl-4-heptanone, 2-octanone, 3-octanone, 2-nonanone, 3-nonanone, 5-nonanone, 2-decanone, 3-decanone, 4-decanone, 5-hexen-2-one 3-penten-2-one, cyclopentanone, 2-methylcyclopentanone, 3-methylcyclopentanone, 2,2-dimethylcyclopentanone, 2,4,4-trimethylcyclopentanone, cyclohexanone, 3- Methylcyclohexanone, 4-methylcyclohexanone, 4-ethylcyclohexanone, 2,2-dimethylcyclohexanone, 2,6-dimethylcyclohexanone, 2,2,6-trimethylcyclohexanone, cycloheptanone, 2-methylcycloheptanone, 3-methyl Preferred is cycloheptanone.

Preferred examples of the alkylene carbonate include propylene carbonate, vinylene carbonate, ethylene carbonate, and butylene carbonate.
Examples of the alkyl alkoxyacetate include 2-methoxyethyl acetate, 2-ethoxyethyl acetate, 2- (2-ethoxyethoxy) ethyl acetate, 3-methoxy-3-methylbutyl acetate, and 1-methoxy-acetate. 2-propyl is preferred.
Preferred examples of the alkyl pyruvate include methyl pyruvate, ethyl pyruvate, and propyl pyruvate.

As a solvent which can be preferably used, a solvent having a boiling point of 130 ° C. or higher under normal temperature and normal pressure can be mentioned. Specifically, cyclopentanone, γ-butyrolactone, cyclohexanone, ethyl lactate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, ethyl 3-ethoxypropionate, ethyl pyruvate, 2-ethoxyethyl acetate, acetic acid -2- (2-ethoxyethoxy) ethyl and propylene carbonate are mentioned.
In the present invention, the above solvents may be used alone or in combination of two or more.

In this invention, you may use the mixed solvent which mixed the solvent which contains a hydroxyl group in a structure, and the solvent which does not contain a hydroxyl group as an organic solvent.
Examples of the solvent containing a hydroxyl group include ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, ethyl lactate, and the like. Particularly preferred are propylene glycol monomethyl ether and ethyl lactate.

  Examples of the solvent not containing a hydroxyl group include propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, butyl acetate, N-methylpyrrolidone, N, N-dimethylacetamide, dimethyl sulfoxide and the like. Among these, propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, and butyl acetate are particularly preferable, and propylene glycol monomethyl ether acetate, ethyl ethoxypropionate. 2-heptanone is most preferred.

  The mixing ratio (mass) of the solvent containing a hydroxyl group and the solvent not containing a hydroxyl group is usually from 1/99 to 99/1, preferably from 10/90 to 90/10, more preferably from 20/80 to 80. / 20.

  The solvent is preferably a mixed solvent of two or more containing propylene glycol monomethyl ether acetate.

Second resist As the second resist used to form the second resist pattern, those described as the first resist can be used as appropriate, but the first resist pattern and the second resist From the viewpoint of making the dry etching resistance of the pattern as much as possible, the resin used for the second resist is preferably substantially the same as the resin used for the first resist. Further, from the viewpoint of stability over time, it may be different from the resin used for the first resist.

Hereinafter, the first resist pattern forming method and the second resist pattern forming method will be described.
<Formation of first resist pattern>
In the present invention, the first resist composition (the resist composition of the present invention) is filtered and then applied onto a predetermined support as follows. The filter used for filter filtration is preferably made of polytetrafluoroethylene, polyethylene, or nylon having a pore size of 0.1 μm or less, more preferably 0.05 μm or less, and still more preferably 0.03 μm or less.

  The filtered resist composition is coated on a substrate (eg, silicon / silicon dioxide coating) used for the manufacture of precision integrated circuit elements by a suitable coating method such as a spinner or a coater, and dried to form a resist film. Form. Heating (pre-baking) is preferably performed at the drying stage, but it is preferable that the temperature of the component (C) is not high enough to crosslink between the resins.

Although there is no restriction | limiting in particular in a film thickness, Preferably it adjusts in the range of 50-200 nm, More preferably, it adjusts in the range of 80-180 nm.
When applying a resist composition with a spinner, the rotation speed is 500-3000 rpm normally, Preferably it is 800-2000 rpm, More preferably, it is 1000-1500 rpm.

Before forming the resist film, an antireflection film may be coated on the substrate in advance.
As the antireflection film, any of an inorganic film type such as titanium, titanium dioxide, titanium nitride, chromium oxide, carbon, and amorphous silicon, and an organic film type made of a light absorber and a polymer material can be used. In addition, as the organic antireflection film, commercially available organic antireflection films such as DUV30 series, DUV-40 series manufactured by Brewer Science, AR-2, AR-3, AR-5 manufactured by Shipley, etc. may be used. it can.

[Dry exposure method]
The resist film is irradiated with actinic rays or radiation through a predetermined mask, preferably post-baked (post-heating), and developed and rinsed. Thereby, a good pattern can be obtained. About post-baking, it is good to suppress to the temperature which the compound of (C) component does not bridge | crosslink between resins.

Examples of the actinic ray or radiation include infrared light, visible light, ultraviolet light, far ultraviolet light, X-ray, electron beam, etc., preferably 250 nm or less, more preferably 220 nm or less, particularly preferably 1 to 1. Far-ultraviolet light having a wavelength of 200 nm, specifically, ArF excimer laser, F ₂ excimer laser, EUV (wavelength 13.5 nm), and electron beam are preferable, and ArF excimer laser is more preferable.

[Immersion exposure method]
In the case of immersion exposure, the resist film is exposed (immersion exposure) through immersion water through a mask or the like for pattern formation. For example, the exposure is performed in a state where the space between the resist film and the optical lens is filled with the immersion liquid. After exposure, the resist film is washed with an immersion liquid as necessary. Subsequently, preferably, spinning is performed to remove the immersion liquid. Examples of the actinic ray or radiation include infrared light, visible light, ultraviolet light, far ultraviolet light, X-ray, electron beam, etc., preferably 250 nm or less, more preferably 220 nm or less, particularly preferably 1 to 1. Far-ultraviolet light having a wavelength of 200 nm, specifically, ArF excimer laser, F ₂ excimer laser, EUV (wavelength 13.5 nm), and electron beam are preferable, and ArF excimer laser is more preferable.

The immersion liquid used for the immersion exposure will be described below.
The immersion liquid is preferably a liquid that is transparent to the exposure wavelength and has a refractive index temperature coefficient as small as possible so as to minimize distortion of the optical image projected onto the resist. In the case of an ArF excimer laser (wavelength: 193 nm), it is preferable to use water from the viewpoints of availability and ease of handling in addition to the above-described viewpoints.

  Further, a medium having a refractive index of 1.5 or more can be used in that the refractive index can be further improved. This medium may be an aqueous solution or an organic solvent.

  When water is used as the immersion liquid, the surface tension of the water is decreased and the surface activity is increased, so that the resist layer on the wafer is not dissolved and the influence on the optical coating on the lower surface of the lens element can be ignored. An additive (liquid) may be added in a small proportion. The additive is preferably an aliphatic alcohol having a refractive index substantially equal to that of water, and specifically includes methyl alcohol, ethyl alcohol, isopropyl alcohol and the like. Since such an additive has a refractive index substantially equal to that of water, even if the additive component in water evaporates to change the content concentration, the refractive index change as a whole liquid is extremely small, which is preferable. On the other hand, when an opaque material or impurities whose refractive index is significantly different from that of water are mixed with 193 nm light, the optical image projected on the resist film is distorted. . Further, pure water filtered through an ion exchange membrane or the like may be used.

  The electrical resistance of water is preferably 18.3 MQcm or more. Moreover, it is preferable that TOC (organic substance density | concentration) is 20 ppb or less. The water is preferably deaerated.

Moreover, it is possible to improve lithography performance by increasing the refractive index of the immersion liquid. From such a viewpoint, an additive for increasing the refractive index may be added to water, or heavy water (D ₂ O) may be used instead of water.

  An immersion liquid poorly soluble film (hereinafter also referred to as “top coat”) may be provided between the resist film and the immersion liquid so that the resist film is not directly brought into contact with the immersion liquid. The necessary functions for the top coat are suitability for application to the upper layer of the resist, radiation, especially transparency to 193 nm, and poor immersion liquid solubility. It is preferable that the top coat is not mixed with the resist and can be uniformly applied to the resist upper layer.

  From the viewpoint of 193 nm transparency, the topcoat is preferably a polymer that does not contain an aromatic, and specifically, a hydrocarbon polymer, an acrylate polymer, a polymethacrylic acid, a polyacrylic acid, a polyvinyl ether, a silicon-containing polymer, And fluorine-containing polymers.

  When peeling the top coat, a developer may be used, or a separate release agent may be used. As the release agent, a solvent having a small penetration into the resist is preferable. It is preferable that the peeling process can be performed with an alkali developer in that the peeling process can be performed simultaneously with the resist development process. From the viewpoint of peeling with an alkaline developer, the topcoat is preferably acidic, but may be neutral or alkaline from the viewpoint of non-intermixability with the resist.

  In the case of immersion exposure, instead of the top coat or in combination with the top coat, a hydrophobic resin (HR) described later is added to the resist composition to form a resist film. Immersion exposure may be performed.

  As a result, hydrophobic resin (HR) is unevenly distributed on the surface of the resist film, and when the immersion medium is water, the receding contact angle of the resist film surface with respect to the water when the resist film is formed is improved, and the immersion water tracking is improved. Can be made. The hydrophobic resin (HR) is a resin whose surface receding contact angle is improved by addition, and preferably a resin having at least one of a fluorine atom and a silicon atom. The receding contact angle of the resist film is preferably 60 ° to 90 °, more preferably 70 ° or more. The addition amount can be adjusted as appropriate so that the receding contact angle of the resist film falls within the above range, but is preferably 0.1 to 10% by mass, more preferably based on the total solid content of the resist composition. Is 0.1-5 mass%. Hydrophobic resin (HR) is unevenly distributed at the interface, but unlike a surfactant, it does not necessarily have a hydrophilic group in the molecule and does not contribute to uniform mixing of polar / nonpolar substances. May be.

  When the hydrophobic resin (HR) is a resin having at least one of a fluorine atom and a silicon atom, it is a resin having an alkyl group having a fluorine atom, a cycloalkyl group having a fluorine atom, or an aryl group having a fluorine atom. It is preferable.

The alkyl group having a fluorine atom (preferably having 1 to 10 carbon atoms, more preferably 1 to 4 carbon atoms) is a linear or branched alkyl group in which at least one hydrogen atom is substituted with a fluorine atom, It may have a substituent.
The cycloalkyl group having a fluorine atom is a monocyclic or polycyclic cycloalkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and may further have another substituent.
Examples of the aryl group having a fluorine atom include those in which at least one hydrogen atom of an aryl group such as a phenyl group or a naphthyl group is substituted with a fluorine atom, and may further have another substituent.

Preferred examples of the alkyl group having a fluorine atom, the cycloalkyl group having a fluorine atom, or the aryl group having a fluorine atom include groups represented by the following general formulas (F2) to (F4). The present invention is not limited to this.

In general formulas (F2) to (F4), R _{57 to} R ₆₈ each independently represent a hydrogen atom, a fluorine atom, or an alkyl group. However, at least one of R _{57 to} R ₆₁ , R _{62 to} R ₆₄ and R _{65 to} R ₆₈ is a fluorine atom or an alkyl group in which at least one hydrogen atom is substituted with a fluorine atom (preferably having a carbon number of 1 ~ 4). R _{57 to} R ₆₁ and R _{65 to} R ₆₇ are preferably all fluorine atoms. R ₆₂ , R ₆₃ and R ₆₈ are preferably an alkyl group (preferably having 1 to 4 carbon atoms) in which at least one hydrogen atom is substituted with a fluorine atom, and preferably a perfluoroalkyl group having 1 to 4 carbon atoms. Further preferred. R ₆₂ and R ₆₃ may be connected to each other to form a ring.

  Specific examples of the group represented by the general formula (F2) include a p-fluorophenyl group, a pentafluorophenyl group, and a 3,5-di (trifluoromethyl) phenyl group.

  Specific examples of the group represented by the general formula (F3) include trifluoromethyl group, pentafluoropropyl group, pentafluoroethyl group, heptafluorobutyl group, hexafluoroisopropyl group, heptafluoroisopropyl group, hexafluoro (2 -Methyl) isopropyl group, nonafluorobutyl group, octafluoroisobutyl group, nonafluorohexyl group, nonafluoro-t-butyl group, perfluoroisopentyl group, perfluorooctyl group, perfluoro (trimethyl) hexyl group, 2,2 1,3,3-tetrafluorocyclobutyl group, perfluorocyclohexyl group and the like. Hexafluoroisopropyl group, heptafluoroisopropyl group, hexafluoro (2-methyl) isopropyl group, octafluoroisobutyl group, nonafluoro-t-butyl group and perfluoroisopentyl group are preferable, and hexafluoroisopropyl group and heptafluoroisopropyl group are preferable. Further preferred.

Specific examples of the group represented by the general formula (F4) include, for example, —C (CF ₃ ) ₂ OH, —C (C ₂ F ₅ ) ₂ OH, —C (CF ₃ ) (CH ₃ ) OH, -CH (CF ₃₎ OH and the like, -C (CF _{3) 2} OH is preferred.

  The hydrophobic resin (HR) is preferably a resin having an alkylsilyl structure (preferably a trialkylsilyl group) or a cyclic siloxane structure as a partial structure having a silicon atom.

Specific examples of the alkylsilyl structure or the cyclic siloxane structure include groups represented by the following general formulas (CS-1) to (CS-3).

In the general formulas (CS-1) to (CS-3), R _{12 to} R ₂₆ are each independently a linear or branched alkyl group (preferably having 1 to 20 carbon atoms) or a cycloalkyl group (preferably Represents C3-20. L < ₃ > -L < ₅ > represents a single bond or a bivalent coupling group. As the divalent linking group, an alkylene group, a phenylene group, an ether group, a thioether group, a carbonyl group, an ester group, an amide group, a urethane group, or a urea group is used alone or in combination of two or more groups. A combination is mentioned. n represents an integer of 1 to 5.

Furthermore, the hydrophobic resin (HR) may have at least one group selected from the following groups (x) to (z).
(X) an alkali-soluble group,
(Y) a group that decomposes by the action of an alkali developer and increases the solubility in the alkali developer;
(Z) A group that decomposes by the action of an acid.

  (X) Alkali-soluble groups include phenolic hydroxyl groups, carboxylic acid groups, fluorinated alcohol groups, sulfonic acid groups, sulfonamido groups, sulfonylimide groups, (alkylsulfonyl) (alkylcarbonyl) methylene groups, (alkylsulfonyl) ( Alkylcarbonyl) imide group, bis (alkylcarbonyl) methylene group, bis (alkylcarbonyl) imide group, bis (alkylsulfonyl) methylene group, bis (alkylsulfonyl) imide group, tris (alkylcarbonyl) methylene group, tris (alkylsulfonyl) And a group having a methylene group.

  Preferred alkali-soluble groups include fluorinated alcohol groups (preferably hexafluoroisopropanol), sulfonimide groups, and bis (carbonyl) methylene groups.

  Examples of the repeating unit having an alkali-soluble group (x) include a repeating unit in which an alkali-soluble group is directly bonded to the main chain of the resin, such as a repeating unit of acrylic acid or methacrylic acid, or a main group of the resin via a linking group. It is preferable to use a repeating unit in which an alkali-soluble group is bonded to the chain, and further introduce a polymerization initiator or chain transfer agent having an alkali-soluble group at the end of the polymer chain at the time of polymerization.

  The content of the repeating unit having an alkali-soluble group (x) is preferably from 1 to 50 mol%, more preferably from 3 to 35 mol%, still more preferably from 5 to 20 mol, based on all repeating units in the hydrophobic resin (HR). %.

  (Y) Examples of the group that decomposes by the action of an alkali developer and increases the solubility in the alkali developer include a group having a lactone structure, an acid anhydride, an acid imide group, and the like, and preferably a lactone group It is.

  As the repeating unit having a group (y) that is decomposed by the action of an alkali developer and increases the solubility in the alkali developer, an alkali is added to the main chain of the resin, such as a repeating unit of an acrylate ester or a methacrylate ester. A polymerization initiator having a repeating unit to which a group (y) that decomposes by the action of the developer and increases the solubility in an alkali developer is bonded, or a group (y) that increases the solubility in an alkali developer And a chain transfer agent used at the time of polymerization are preferably introduced at the end of the polymer chain.

  The content of the repeating unit having a group (y) whose solubility in an alkali developer is increased is preferably 1 to 40 mol%, more preferably 3 to 30 mol, based on all repeating units in the hydrophobic resin (HR). %, More preferably 5 to 15 mol%.

  Specific examples of the repeating unit having a group (y) that increases the solubility in an alkali developer include the same repeating units as those having a lactone structure exemplified for the resin of the component (B).

In the hydrophobic resin (HR), examples of the repeating unit having a group (z) that is decomposed by the action of an acid are the same as the repeating unit having an acid-decomposable group listed for the resin (A). In the hydrophobic resin (HR), the content of the repeating unit having a group (z) that decomposes by the action of an acid is preferably 1 to 80 mol% with respect to all the repeating units in the hydrophobic resin (HR). More preferably, it is 10-80 mol%, More preferably, it is 20-60 mol%.
The hydrophobic resin (HR) may further have a repeating unit represented by the following general formula (IV).

In the general formula (IV), R ₄ represents a group having an alkyl group, a cycloalkyl group, an alkenyl group, or a cycloalkenyl group.
L ₆ represents a single bond or a divalent linking group.

In general formula (III), the alkyl group represented by R ₄ is preferably a linear or branched alkyl group having 3 to 20 carbon atoms. The cycloalkyl group is preferably a cycloalkyl group having 3 to 20 carbon atoms. The alkenyl group is preferably an alkenyl group having 3 to 20 carbon atoms. The cycloalkenyl group is preferably a cycloalkenyl group having 3 to 20 carbon atoms.
The divalent linking group of L ₆ is preferably an alkylene group (preferably having 1 to 5 carbon atoms) or an oxy group.

  When the hydrophobic resin (HR) has a fluorine atom, the fluorine atom content is preferably 5 to 80% by mass, and 10 to 80% by mass with respect to the molecular weight of the hydrophobic resin (HR). Is more preferable. Moreover, it is preferable that the repeating unit containing a fluorine atom is 10-100 mass% in hydrophobic resin (HR), and it is more preferable that it is 30-100 mass%.

  When the hydrophobic resin (HR) has a silicon atom, the content of the silicon atom is preferably 2 to 50% by mass and preferably 2 to 30% by mass with respect to the molecular weight of the hydrophobic resin (HR). Is more preferable. Moreover, it is preferable that it is 10-100 mass% in hydrophobic resin (HR), and, as for the repeating unit containing a silicon atom, it is more preferable that it is 20-100 mass%.

  The weight average molecular weight of the hydrophobic resin (HR) in terms of standard polystyrene is preferably 1,000 to 100,000, more preferably 1,000 to 50,000, and even more preferably 2,000 to 15,000. is there.

  As in the case of the resin (A), the hydrophobic resin (HR) preferably has 0 to 10% by mass of residual monomer and oligomer components, and more preferably has few impurities such as metals. 0-5 mass% and 0-1 mass% are still more preferable. Thereby, a resist having no change over time such as foreign matter in liquid or sensitivity can be obtained. The molecular weight distribution (Mw / Mn, also referred to as dispersity) is preferably in the range of 1 to 5, more preferably 1 to 3, and still more preferably from the viewpoints of resolution, resist shape, resist pattern sidewall, roughness, and the like. It is the range of 1-2.

  Various commercially available products can be used as the hydrophobic resin (HR), and the hydrophobic resin (HR) can also be synthesized according to a conventional method. Examples of the method for synthesizing and purifying the resin include the same methods as those used for the first resist and the second resist, which are decomposed by the action of an acid and increase the solubility in an alkaline developer. .

Specific examples of the hydrophobic resin (HR) are shown below. Table 1 below shows the molar ratio of the repeating units in each resin (corresponding to each repeating unit in order from the left), the weight average molecular weight, and the degree of dispersion.

  After the dry exposure or immersion exposure, post-baking (post-heating) is preferably performed, and development and rinsing are performed. Thereby, a good pattern can be obtained.

  In the development step, an alkali developer is usually used. As an alkaline developer of the resist composition, inorganic hydroxides such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia, primary amines such as ethylamine and n-propylamine, Secondary amines such as diethylamine and di-n-butylamine, tertiary amines such as triethylamine and methyldiethylamine, alcohol amines such as dimethylethanolamine and triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide and the like Alkaline aqueous solutions such as quaternary ammonium salts, cyclic amines such as pyrrole and pihelidine can be used.

Furthermore, alcohols and surfactants can be appropriately added to the alkaline developer for use.
The alkali concentration of the alkali developer is usually from 0.1 to 20% by mass. The pH of the alkali developer is usually from 10.0 to 15.0.

As the rinsing liquid, pure water is usually used, and an appropriate amount of a surfactant can be added and used.
In addition, after the developing process or the rinsing process, a process of removing the developing solution or the rinsing liquid adhering to the pattern with a supercritical fluid can be performed. Moreover, the process which removes the developing solution or rinse liquid which remain | survives by heating can be performed. In this case, the heating temperature is usually 60 ° C. or higher and 200 ° C. or lower, and preferably 80 ° C. or higher and 150 ° C. or lower. (C) It is good to suppress to the temperature which the compound of a component does not bridge | crosslink between resins.

  Further, after the rinsing process or the supercritical fluid process, a heat treatment can be performed to remove moisture remaining in the pattern.

<First resist pattern heat treatment>
After the first resist pattern is formed on the first resist film using the above method, the first resist pattern is heat-treated. It is considered that the resin is cross-linked by a functional group that cross-links between the resins by heating the compound (C) by the heat treatment, and reacts with the component (C) to cause cross-polymer cross-linking, thereby curing the resist pattern. As heating temperature, it is 60 degreeC or more and 200 degrees C or less normally, and 80 degreeC or more and 150 degrees C or less are preferable.

  As another method for further promoting the reaction of the resist pattern, it is possible to uniformly expose the first resist pattern without using a mask after the formation of the first resist pattern. Further, the substrate may be further heated after exposure. Although the reason for this is not clear, the component (B) which has not been decomposed at the time of forming the first resist pattern is probably decomposed by exposure to generate an acid. It is thought that by performing heating thereafter, a carboxyl group is generated in the component (A), and the number of reaction points with the active functional group in the component (A) is increased so that curability is improved.

The exposure light when performing the exposure is preferably the exposure light source used in forming the first resist pattern, but the photoacid generator present in the first resist pattern is decomposed to generate an acid. Any exposure light source may be used as long as it is generated. The amount of exposure is not particularly limited, but is preferably between 5 and 20 mJ / cm ² . The heating temperature is not particularly limited as long as the resist pattern shape is not deteriorated, but is preferably 30 ° C. or higher and 250 ° C. or lower, more preferably 50 ° C. or higher and 200 ° C. or lower, and most preferably 50 ° C. or higher and 180 ° C. or lower.

<Formation of second resist pattern>
In the present invention, after filtering the second resist composition, the second resist composition is applied to the substrate on which the first resist pattern is formed. The filter used for filter filtration is preferably made of polytetrafluoroethylene, polyethylene or nylon having a pore size of 0.1 microns or less, more preferably 0.05 microns or less, and still more preferably 0.03 microns or less.

As a method for forming the second resist film and a method for forming the second resist pattern, the same method as the method for forming the first resist film and the method for forming the first resist pattern should be used. Can do.
The film thickness of the second resist film is preferably equal to or greater than the film thickness of the first resist pattern. Thereby, the second resist pattern can be formed at the same height.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to the following examples.
<Synthesis of Resin (A)>
[Synthesis of Resin 1]
Under a nitrogen stream, 61.2 g of PGME (propylene glycol monomethyl ether) / PGMEA (propylene glycol monomethyl ether acetate) (mass ratio 4/6) was placed in a three-necked flask and heated to 80 ° C. Monomer (M11) 13.4 g, (M21) 3.6 g, (M31) 3.8 g, (M41) 15.2 g, polymerization initiator V-60 (manufactured by Wako Pure Chemical Industries), A solution dissolved in 142.7 g of PGME / PGMEA (mass ratio 4/6) was added dropwise over 6 hours. After completion of the dropping, the reaction was further carried out at 80 ° C. for 2 hours. The reaction solution was allowed to cool and then added dropwise to a mixture of 2000 ml of hexane / 400 ml of ethyl acetate over 20 minutes, and the precipitated powder was collected by filtration and dried to obtain 30.5 g. The weight average molecular weight (Mw) of the obtained resin was 8700 in terms of standard polystyrene by GPC measurement, and the dispersity (Mw / Mn) was 1.75.

[Synthesis of Resins 2-7]
Resins 2 to 7 were synthesized by the same synthesis method as for resin 1.
Table 2 shows the monomer types used in the obtained resins 1 to 7, the composition ratio, the weight average molecular weight (Mw), and the dispersity (Mw / Mn).

<Preparation of resist composition>
The components shown in Tables 3 to 5 below are dissolved in a solvent, and a solution with a solid content concentration of 5.8% by mass is prepared for each, and this is filtered through a polyethylene filter having a pore size of 0.1 μm, and a positive resist solution. Was prepared.

[Basic compounds]
TPI: 2,4,5-triphenylimidazole PEA: N-phenyldiethanolamine DPA: 2,6-diisopropylphenyl alcohol PBI: 2-phenylbenzimidazole [Surfactant]
W-1: MegaFuck F176 (Dainippon Ink Chemical Co., Ltd.) (Fluorine)
W-2: Megafuck R08 (Dainippon Ink Chemical Co., Ltd.) (fluorine and silicon)
W-3: Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) (silicon-based)
〔solvent〕
A1: Propylene glycol monomethyl ether acetate A2: γ-butyrolactone A3: Cyclohexanone B1: Propylene glycol monomethyl ether B2: Ethyl lactate The prepared positive resist solution was used for evaluation by the following method.

<Pattern formation>
[ArF dry exposure]
Hereinafter, a pattern forming method subjected to a freezing process (heating process) will be described with reference to FIG.

  An organic antireflection film (ARC29A (manufactured by Nissan Chemical Industries)) was applied on the silicon wafer 3 and baked at 205 ° C. for 60 seconds to form an antireflection film 4 having a film thickness of 78 nm. A positive resist composition (first positive resist composition) prepared thereon was applied, and baked at 110 ° C. for 60 seconds to form a first resist film 1 having a thickness of 160 nm (FIG. 2). (A)).

  Next, the wafer coated with the resist film 1 was subjected to pattern exposure using an ArF excimer laser scanner (PAS5500 / 1100 manufactured by ASML) through an exposure mask m1 (line / space = 1/3) (FIG. 2B). )). The exposure amount at this time was set to an optimum exposure amount that provides a desired line width. After heating at 110 ° C. for 60 seconds, developing with an aqueous tetramethylammonium hydroxide solution (2.38 mass%) for 30 seconds, rinsing with pure water, spin drying, and 1/3 (pitch 520 nm line width 130 nm) ) First resist pattern 1a was obtained (FIG. 2C).

  Thereafter, the wafer on which the first resist pattern 1a was formed was baked at 140 ° C. for 120 seconds to form a first pattern 1a ′ subjected to a freezing process (heating process) (FIG. 2D).

  The prepared positive resist composition (second positive resist composition) is applied to the wafer on which the heat-treated first resist pattern 1a ′ is formed, and baked at 110 ° C. for 60 seconds. A second resist film 2 having a thickness of 160 nm was formed (FIG. 2E). Pattern exposure was performed using an ArF excimer laser scanner (PAS5500 / 1100, manufactured by ASML) through the exposure mask m2 (FIG. 2 (f)). The exposure amount at this time was set to an optimum exposure amount that provides a desired line width. Thereafter, the mixture was heated at 110 ° C. for 60 seconds, developed with a tetramethylammonium hydroxide aqueous solution (2.38 mass%) for 30 seconds, rinsed with pure water, and then spin-dried. In this way, a pattern in which the first resist pattern 1a 'and the second resist pattern 2a were arranged on the wafer at 1/1 (pitch 260 nm, line width 130 nm) was formed (FIG. 2 (g)).

[ArF immersion exposure]
Using pure water as the immersion liquid, and using TWINSCAN XT: 1700Fi manufactured by ASML equipped with a lens of NA 0.85 as the ArF excimer laser scanner, the final pattern dimensions were changed to a pitch of 130 nm and a line width of 65 nm. A pattern was formed using the same method as that shown in the above “ArF dry exposure” except that the film thickness was changed to 130 nm.

<Evaluation method>
[Changes in LER]
The LER fluctuations are as follows. For the resist pattern 1, LER (x) of the resist pattern 1 before the freezing treatment (pattern 1a in FIG. 2C) and the first resist pattern after forming the second resist pattern. Evaluation was made based on the difference (y−x) in LER (y) of (pattern 1a ′ in FIG. 2 (g)).

  The LER is measured by observing the resist pattern using a length-measuring scanning electron microscope (SEM), and measuring the distance from the reference line that should have an edge in the range where the longitudinal edge of the line pattern is 5 μm. 50 points were measured by Hitachi, Ltd. S-8840), the standard deviation was obtained, and 3σ was calculated. A smaller value indicates better performance.

[Pattern shape]
The shape of the first resist pattern (pattern 1a ′ in FIG. 2G) after forming the second resist pattern was measured by SEM (Hitachi Ltd. S-4800), and the pattern shape was evaluated. .

The evaluation results are shown in Table 6.

  From the results of Table 6, the first resist pattern formed using the resist composition of the present invention is compared with the case where the resist composition is not used in the characteristic evaluation by ArF dry exposure and ArF immersion exposure. It does not dissolve in the second resist solution and the alkaline developer used to form the second resist pattern, and even after the second resist pattern is formed, the shape of the first resist pattern does not deteriorate and LER fluctuation is suppressed. I found out that

The schematic process drawing explaining an example of the conventional double patterning method. The schematic process drawing explaining the pattern formation method used in the Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... 1st resist film, 3 ... Silicon wafer, 4 ... Antireflection film, m1 ... 1st exposure mask, 1a ... 1st resist pattern before heat processing, 1a '... first resist pattern after heat treatment, 2 ... second resist film, m2 ... second exposure mask, 2a ... second resist pattern, 101 ... semiconductor substrate , 102... Hard mask, 103, 105... Resist film, 103a, 105a... Unexposed portion of resist film (resist pattern), 103b, 105b... Exposed portion of resist film, 104 106: Exposure mask

Claims (9)

  (A) a resin whose solubility in an alkaline developer is increased by the action of an acid, (B) a compound that generates an acid upon irradiation with actinic rays or radiation, and (C) a compound having a functional group that crosslinks between the resins by heating, Containing a positive resist composition.   2. The positive resist composition according to claim 1, wherein the functional group that crosslinks between the resins by heating in the compound (C) is a blocked isocyanate group or a blocked thioisocyanate group.   Resin (A) can react with (a1) a repeating unit containing a group that decomposes by the action of an acid to generate an alkali-soluble group, and (a2) a functional group that crosslinks between the resins by heating in compound (C). The positive resist composition according to claim 1, which has a repeating unit containing a group.   The group which can react with the functional group which bridge | crosslinks between resin in heating in a repeating unit (a2) is a hydroxyl group, a carboxyl group, an amino group, an amide group, a thiol group, or an active methylene group. A positive resist composition.   The positive resist composition according to any one of claims 1 to 4, wherein the resin (A) further has (a3) a repeating unit having a lactone group.   Furthermore, the positive resist composition of any one of Claims 1-5 containing the compound containing the group which can react with the functional group which bridge | crosslinks between resin by the heating in (D) compound (C). .   The group which can react with the functional group which bridge | crosslinks between resins in a compound (D) is a hydroxyl group, a carboxyl group, an amino group, an amide group, a thiol group, or an active methylene group of Claim 6. Positive resist composition.   A first resist pattern forming step of forming a first resist pattern from the first resist film, and a second resist film is formed on the first resist pattern obtained in the step; The positive type according to any one of claims 1 to 7, which is used for forming a first resist pattern in a resist pattern forming method including a second resist pattern forming step of forming a second resist pattern from Resist composition.   A step of forming a first photosensitive layer using the positive resist composition according to any one of claims 1 to 8 on a substrate, and selectively exposing and developing the first photosensitive layer through a mask. The step of forming the first pattern, the step of heating the substrate on which the first pattern is formed, the second using the second positive resist composition on the heated substrate on which the first pattern is formed Forming a photosensitive layer, and selectively exposing and developing the second photosensitive layer through a mask to form a second pattern.

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