JP5222981B2 - Positive resist composition and pattern forming method - Google Patents

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 also in 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 an immersion projection exposure apparatus using far ultraviolet light having a wavelength of 300 nm or less as a light source, and a pattern forming method using the same.

With the miniaturization of semiconductor elements, the exposure light source has become shorter in wavelength and the projection lens has a higher numerical aperture (high NA). Currently, an exposure machine with a NA of 0.84 has been developed using an ArF excimer laser having a wavelength of 193 nm as a light source. ing. These can be expressed by the following equations as is generally well known.
(Resolving power) = k ₁ · (λ / NA)
(Depth of focus) = ± k ₂ · λ / NA ²
Here, λ is the wavelength of the exposure light source, NA is the numerical aperture of the projection lens, and k ₁ and k ₂ are coefficients related to the process.

An exposure machine using an F ₂ excimer laser having a wavelength of 157 nm as a light source has been studied for higher resolution by further shortening the wavelength. However, a lens material and a resist used in an exposure apparatus for shortening the wavelength are being studied. Because the materials used in the process are very limited, it is very difficult to stabilize the manufacturing cost and quality of the apparatus and materials, and the exposure apparatus and resist that have sufficient performance and stability within the required period are not in time. The possibility is coming out.

As a technique for increasing the resolving power in an optical microscope, a so-called immersion method in which a high refractive index liquid (hereinafter also referred to as “immersion liquid”) is filled between a projection lens and a sample is known.
As for the "effect of immersion", the lambda ₀ is the wavelength of exposure light in air, the refractive index of the immersion liquid to air is n, the θ and convergence half of the light beam and when the NA 0 ₌ sin [theta, and immersion In this case, 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
(Depth of focus) = ± k ₂ · (λ ₀ / n) / NA ₀ ²
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. This is effective for all pattern shapes, and can be combined with a super-resolution technique such as a phase shift method and a modified illumination method which are currently being studied.

Examples of apparatuses in which this effect is applied to the transfer of a fine image pattern of a semiconductor element are introduced in Patent Document 1 (Japanese Patent Laid-Open No. 57-153433), Patent Document 2 (Japanese Patent Laid-Open No. 7-220990), and the like. Yes.
Recent advances in immersion exposure technology include Non-Patent Document 1 (SPIE Proc 4688, 11 (2002)), Non-Patent Document 2 (J. Vac. Sci. Tecnol. B17 (1999)), Non-Patent Document 3 (SPIE Proc 3999). 2 (2000)), Patent Document 3 (International Publication WO 2004-077158 Pamphlet) and the like.
In the case of using an ArF excimer laser as a light source, pure water (refractive index of 1.44 at 193 nm) is considered to be most promising as an immersion liquid in terms of handling safety, transmittance at 193 nm, and refractive index. When an F2 excimer laser is used as a light source, a solution containing fluorine has been studied from the balance between transmittance and refractive index at 157 nm, but a sufficient product has not yet been found in terms of environmental safety and refractive index. It has not been. From the degree of immersion effect and the degree of completeness of the resist, the immersion exposure technique is considered to be installed in the ArF exposure machine earliest.

Since the resist for KrF excimer laser (248 nm), an image forming method called chemical amplification has been used as an image forming method for a resist in order to compensate for sensitivity reduction due to light absorption. 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.
Although the resist for ArF excimer laser (wavelength 193 nm) using this chemical amplification mechanism is becoming mainstream at present, there is a problem that the formed line pattern collapses and becomes a defect at the time of device manufacture. It was sought after.

It is pointed out that when chemically amplified resist is applied to immersion exposure, the resist layer comes into contact with the immersion liquid at the time of exposure, so that the resist layer is altered and components that adversely affect the immersion liquid are leached from the resist layer. Has been. Patent Document 4 (International Publication WO 2004-068242 Pamphlet) describes an example in which resist performance changes by immersing a resist for ArF exposure in water before and after exposure, and points to a problem in immersion exposure. .
In addition, when immersion exposure is performed, circular defects called watermarks may occur due to the action of water droplets remaining on the resist film after exposure, and improvements are required.

JP-A-57-153433 JP-A-7-220990 International Publication No. 2004/071158 International Publication No. 2004/068242

Bulletin of International Society of Optical Engineering (Proc. SPIE), 2002, 4688, 11 J. et al. Vac. Sci. Tecnol. B17 (1999) Bulletin of International Society of Optical Engineering (Proc. SPIE), 2000, 3999, 2nd page

  An object of the present invention is to provide a positive resist composition capable of suppressing the generation of a watermark during immersion exposure and a pattern forming method using the same in view of the above-described problems of the prior art.

[1]
(A) The repeating unit (a1) having a structure selected from the following general formulas (a1-1) and (a1-3), the repeating unit (a2) represented by the following general formula (a2), and the following general formula A resin containing a repeating unit (a3) having a structure selected from (a3-1) to (a3-4) and having an increased dissolution rate in an alkali developer by the action of an acid;
(B) a compound that generates an acid upon irradiation with an actinic ray or radiation,
(C) Resin containing fluorine and / or silicon atom and containing at least one group selected from the group of groups represented by the following ( y ) , (z) , (f) and the following general formula (F3) And (D) a solvent,
The positive resist composition characterized by containing.
(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 ,
(F) a C1-C4 alkyl group having a fluorine atom, a cycloalkyl group having a fluorine atom, or an aryl group having a fluorine atom.

Where
R represents a hydrogen atom, a halogen atom or an alkyl group.
R ′ represents an acid-decomposable group.
R ₁₂ and R ₁₃ each independently represents a hydrogen atom, a methyl group, an ethyl group or a propyl group.
R ₁₄ represents an alicyclic group.
n represents an integer of 0 to 5.

In general formula (F3),
R _{62 to} R ₆₄ each independently represents a hydrogen atom, a fluorine atom or an alkyl group. However, at least one of R _{62 to} R ₆₄ represents an alkyl group in which at least one hydrogen atom is substituted with a fluorine atom.
[2]
The positive resist composition as described in [1], wherein the resin (A) further contains a repeating unit (a4) having any one of the following structures (a4-1) to (a4-3):

Where
R represents a hydrogen atom, a halogen atom or an alkyl group.
[3]
The positive resist composition according to [1] or [2], wherein the resin (C) is a resin containing a group represented by the general formula (F3) .
[4]
[1] or [2], wherein the resin (C) is a resin containing (y) a group that decomposes by the action of an alkali developer and increases the solubility in the alkali developer. A positive resist composition.
[5]
The positive resist composition as described in [4], wherein the group (y) which is decomposed by the action of the alkali developer and increases the solubility in the alkali developer is a group having a lactone structure .
[6]
The positive resist composition as described in [1] or [2], wherein the resin (C) is a resin containing a group decomposable by the action of (z) acid.
[7]
The group (z) decomposed by the action of the acid is a group in which the hydrogen atom of the —COOH group is substituted with a group capable of leaving with an acid represented by —C (R ₃₆ ) (R ₃₇ ) (R ₃₈ ). The positive resist composition as described in [6], wherein
(In the above formula, R _{36 to} R ₃₈ each independently represents an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group or an alkenyl group, and R ₃₆ and R ₃₇ are bonded to each other to form a ring. May be.)
[8]
The positive resist composition as described in [1] or [2], wherein the resin (C) has at least one repeating unit having a lactone group.
[9]
The resin (C) is an alkali-soluble compound containing (f) an alkyl group having 1 to 4 carbon atoms having a fluorine atom, a cycloalkyl group having a fluorine atom, or an aryl group having a fluorine atom. The positive resist composition according to [1] or [2].
[10]
The positive resist composition as described in [1] or [2], wherein the resin (C) has an alcoholic hydroxyl group, and the alcohol part of the alcoholic hydroxyl group is a fluorinated alcohol.
[11]
The positive type according to any one of [1] to [10], wherein the content of the resin (C) is 0.1 to 10% by mass based on the total solid content of the resist composition. Resist composition.
[12]
The positive resist composition as described in [11], wherein the content of the resin (C) is 0.1 to 5% by mass based on the total solid content of the resist composition.
[13]
The positive resist composition as described in any one of [1] to [12], wherein the solvent (D) is a mixed solvent of two or more containing propylene glycol monomethyl ether acetate.
[14]
The positive resist composition as described in any one of [1] to [12], wherein the solvent (D) is a mixed solvent of two or more containing ethyl lactate and propylene glycol monomethyl ether acetate.
[15]
The positive resist composition as described in any one of [1] to [14], further comprising (E) a basic compound.
[16]
The positive resist composition as described in any one of [1] to [15], wherein the compound (B) is a compound represented by the following general formula (b-1).

In the above general formula,
Rb _{1 to} Rb ₃ each independently represents an alkyl group, a cycloalkyl group or an aryl group, and at least one of Rb _{1 to} Rb ₃ represents an aryl group.
Xb represents a fluorinated alkylene group having 2 to 6 carbon atoms.
[17]
The positive resist composition as described in any one of [1] to [16], wherein the compound (B) has a triphenylsulfonium cation structure.
[18]
[1] A resist film formed from the positive resist composition according to any one of [17].
[19]
A pattern forming method comprising: forming a resist film from the resist composition according to any one of [1] to [17], exposing and developing the resist film.
The present invention relates to the above [1] to [19], but hereinafter, other matters (for example, <1> to <17> below) are also described.

<1>
(A) The repeating unit (a1) having a structure selected from the following general formulas (a1-1) and (a1-3), the repeating unit (a2) represented by the following general formula (a2), and the following general formula A resin containing a repeating unit (a3) having a structure selected from (a3-1) to (a3-4) and having an increased dissolution rate in an alkali developer by the action of an acid;
(B) a compound that generates an acid upon irradiation with an actinic ray or radiation,
(C) a positive electrode characterized by containing a fluorine and / or silicon atom, a resin containing at least one group selected from the following groups (x) to (z), and (D) a solvent. Type resist composition.
(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.

Where
R represents a hydrogen atom, a halogen atom or an alkyl group.
R ′ represents an acid-decomposable group.
R ₁₂ and R ₁₃ each independently represents a hydrogen atom, a methyl group, an ethyl group or a propyl group.
R ₁₄ represents an alicyclic group.
n represents an integer of 0 to 5.
<2>
2. The positive resist composition as described in 1 above, wherein the resin (A) further comprises a repeating unit (a4) having any one of the following structures (a4-1) to (a4-3):

Where
R represents a hydrogen atom, a halogen atom or an alkyl group.
<3>
3. The positive resist composition as described in 1 or 2 above, wherein the compound (C) has at least one repeating unit having a lactone group.
<4>
The above 1 or 2, wherein the compound (C) is an alkali-soluble compound containing an alkyl group having 1 to 4 carbon atoms having a fluorine atom, a cycloalkyl group having a fluorine atom, or an aryl group having a fluorine atom. 2. The positive resist composition according to 2.
<5>
3. The positive resist composition as described in 1 or 2 above, wherein the compound (C) has an alcoholic hydroxyl group, and the alcohol moiety of the alcoholic hydroxyl group is a fluorinated alcohol.
<6>
6. The positive resist composition as described in any one of 1 to 5 above, wherein the solvent (D) is a mixed solvent of two or more containing propylene glycol monomethyl ether acetate.
<7>
6. The positive resist composition as described in any one of 1 to 5 above, wherein the solvent (D) is a mixed solvent of two or more containing ethyl lactate and propylene glycol monomethyl ether acetate.
<8>
The positive resist composition as described in any one of 1 to 7 above, further comprising (E) a basic compound.
<9>
9. The positive resist composition as described in any one of 1 to 8 above, wherein the compound (B) has a triphenylsulfonium cation structure.
<10>
10. The positive resist composition as described in any one of 1 to 9 above, wherein the basic compound (E) is a triethanolamine compound.
<11>
10. The positive resist composition as described in any one of 1 to 9 above, wherein the compound (B) includes a compound represented by the following general formula (b-1) or (b-2).

Where
Rb _{1 to} Rb ₃ each independently represents an alkyl group, a cycloalkyl group or an aryl group, and at least one of Rb _{1 to} Rb ₃ represents an aryl group.
Xb represents a fluorinated alkylene group having 2 to 6 carbon atoms.
Yb and Zb each independently represents an alkyl group.
<12>
The positive resist composition as described in any one of 1 to 11 above, further comprising at least one selected from fluorine atoms, silicon atoms, and surfactants containing both fluorine atoms and silicon atoms.
<13>
The positive resist composition as described in any one of 1 to 12 above, wherein the compound (C) is solid at 25 ° C.
<14>
14. The positive resist composition as described in any one of 1 to 13 above, wherein the compound (C) has a glass transition temperature in the range of 50 to 200 ° C.
<15>
15. The positive resist composition as described in any one of 1 to 14 above, wherein the compound (C) is a resin having a weight average molecular weight of 1,000 to 50,000.
<16>
The positive resist composition as described in any one of 1 to 15 above, wherein the compound (C) is contained in an amount of 0.1 to 5% by mass relative to the total solid content in the positive resist composition.
<17>
A pattern forming method comprising: forming a resist film from the resist composition according to any one of 1 to 16 above, and exposing and developing the resist film.

  INDUSTRIAL APPLICABILITY According to the present invention, a positive resist composition capable of suppressing the generation of a watermark during immersion exposure and a pattern forming method using the same are provided. Furthermore, the positive resist composition of the present invention can reduce film loss during immersion exposure.

An example of a water mark defect.

Hereinafter, the present invention will be described in detail.
In addition, in the description of the group (atomic group) in this specification, the description which does not describe substitution and non-substitution includes what does not have a substituent and what has 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).

(A) Resin whose dissolution rate in an alkaline developer is increased by the action of an acid Resin (resin (A)) whose dissolution rate in an alkaline developer is increased by the action of an acid used in the positive resist composition of the present invention. Also includes a (meth) acrylate unit (a1) having a lactone ring, a (meth) acrylate unit (a2) having an organic group having a polar group, and an acid-decomposable group (acid dissociable, dissolution inhibiting group). It is a three or more-component copolymer containing the (meth) acrylate unit (a3).
By including the repeating unit (a1) derived from acrylic acid or methacrylic acid ester having a lactone ring, adhesion to the substrate can be improved and affinity with the developer can be improved, and film peeling is suppressed. it can.
The repeating unit (a2) containing an organic group having a polar group is specifically a structural unit derived from acrylic acid or methacrylic acid ester having a polar group-containing aliphatic or alicyclic hydrocarbon group, Examples of the group include a hydroxyl group, a cyano group, and an amino group, but a hydroxyl group is preferable.
The repeating unit (a3) derived from an acid-decomposable group-containing acrylic acid or methacrylic acid ester provides an adamantyl group, norbornyl group, tetracyclo group in terms of providing a resist pattern having high resolution and excellent etching resistance. It preferably has an alicyclic group such as a decanyl group.
As a content ratio of the repeating units (a1), (a2) and (a3), (a1) is 20 to 60 mol%, preferably 20 to 50 mol%, (a3) is 30 to 60 mol%, preferably 30 to When the content is in the range of 50 mol%, a resist composition having excellent resolution can be obtained, and when the structural unit (a2) is in the range of 50 mol% or less, preferably in the range of 10 to 40 mol%, the resist composition is excellent. This is preferable because it gives a resist pattern shape.
As repeating units (a-1), (a-2) and (a-3), one from bicycloalkane, tricycloalkane, tetracycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, etc. Alternatively, a group formed by removing two or more hydrogen atoms, particularly those having an adamantyl group, a norbornyl group, a tetracyclodecanyl group or the like.

  Specifically, the resin (A) includes a repeating unit (a1) having a structure selected from the following general formulas (a1-1) to (a1-3), and a repeating unit (a2) represented by the following general formula (a2): And a repeating unit (a3) having a structure selected from the following general formulas (a3-1) to (a3-4), and a resin whose dissolution rate in an alkaline developer is increased by the action of an acid.

Where
R represents a hydrogen atom, a halogen atom or an alkyl group.
R ′ represents an acid-decomposable group.
R ₁₂ and R ₁₃ each independently represents a hydrogen atom, a methyl group, an ethyl group or a propyl group.
R ₁₄ represents an alicyclic group.
n represents an integer of 0 to 5.

An acid-decomposable group is a group that decomposes by the action of an acid to produce an alkali-soluble group. A preferable group as the acid-decomposable group is a group in which a hydrogen atom of an alkali-soluble group is substituted with a group capable of leaving with an acid.
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) Imido 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 A group having
Preferred alkali-soluble groups include carboxylic acid groups, fluorinated alcohol groups (preferably hexafluoroisopropanol), and sulfonic acid groups.
As the acid eliminable group, there can be, for _{example, -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 to} 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.

  The alicyclic group is specifically an alicyclic hydrocarbon group, and may be monocyclic or polycyclic. Specific examples include groups having a monocyclo, bicyclo, tricyclo, tetracyclo structure or the like having 5 or more carbon atoms. The carbon number is preferably 6-30, and particularly preferably 7-25. These alicyclic hydrocarbon groups may have a substituent.

  Below, the structural example of an alicyclic part is shown among alicyclic hydrocarbon groups.

  In the present invention, preferred examples of the alicyclic moiety include an adamantyl group, a noradamantyl group, a decalin residue, a tricyclodecanyl group, a tetracyclododecanyl group, a norbornyl group, a cedrol group, a cyclohexyl group, and a cycloheptyl group. Group, cyclooctyl group, cyclodecanyl group and cyclododecanyl group. More preferred are an adamantyl group, a decalin residue, a norbornyl group, a cedrol group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclodecanyl group, and a cyclododecanyl group.

  Examples of the substituent for these alicyclic hydrocarbon groups include an alkyl group, a halogen atom, a hydroxyl group, an alkoxy group, a carboxyl group, and an alkoxycarbonyl group. The alkyl group is preferably a lower alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group or a butyl group, more preferably a methyl group, an ethyl group, a propyl group or an isopropyl group. Examples of the alkoxy group include those having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. The alkyl group and the alkoxy group may have a further substituent. Examples of further substituents on the alkyl group and alkoxy group include a hydroxyl group, a halogen atom, and an alkoxy group.

  The resin (A) preferably further contains a repeating unit (a4) having any one of the following structures (a4-1) to (a4-3).

In the formula, R represents a hydrogen atom, a halogen atom or an alkyl group.

  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 (I) is 20 to 50 mol%, the (meth) acrylate repeating unit having a lactone structure 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. .

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, generation | occurrence | production of the particle at the time of a preservation | save 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 examples of the initiator 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 60-100 ° C.
The weight average molecular weight of the component (A) resin is preferably from 1,000 to 200,000, more preferably from 3,000 to 20,000, and most preferably from 5,000 to 200 in terms of polystyrene by GPC method. 15,000. By setting the weight average molecular weight to 1,000 to 200,000, deterioration of heat resistance and dry etching resistance can be prevented, developability is deteriorated, and viscosity is increased, resulting in deterioration of film forming property. Can be prevented.
The degree of dispersion (molecular weight distribution) is usually from 1 to 5, preferably from 1 to 3, more preferably from 1 to 2. 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.

When the resin (A) contains the repeating unit (a4), the content of the repeating unit (a4) in the resin (A) is preferably 0.5 mol% to 20 mol%, more preferably 1 mol% to 10 mol%. Mol%.
Each of the repeating units (a1) to (a4) may include a plurality of types.

In the positive resist composition of the present invention, the blending amount of the resin as the component (A) in the whole composition is preferably 50 to 99.99% by mass, more preferably 60 to 99.0% by mass in the total solid content. It is.
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 photosensitive composition of the present invention contains a compound that generates acid upon irradiation with actinic ray or radiation (also referred to as component (B) or compound (B)). To do.
Examples of such photoacid generators include photoinitiators for photocationic polymerization, photoinitiators for photoradical polymerization, photodecolorants for dyes, photochromic agents, actinic rays used in microresists, etc. Known compounds that generate an acid upon irradiation with radiation 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, for example, US Pat. No. 3,849,137, German Patent No. 3914407. JP, 63-26653, JP, 55-164824, JP, 62-69263, JP, 63-146038, JP, 63-163452, JP, 62-153853, The compounds described in JP-A 63-146029 can be used.

  Further, compounds capable of generating an acid by light described in US Pat. No. 3,779,778, European Patent 126,712 and the like can also be used.

The component (B) is preferably a compound that generates an acid having a fluoroalkyl chain (preferably having 2 to 4 carbon atoms) or a benzenesulfonic acid having a fluorine atom upon irradiation with actinic rays.
In addition, the component (B) is a trivalent cation having an alkyl residue that is not fluorine-substituted (preferably having 1 to 15 carbon atoms) or a cycloalkyl residue that is not fluorine-substituted (preferably having 3 to 15 carbon atoms). A phenylsulfonium salt compound is preferred.

  Among the compounds that decompose upon irradiation with actinic rays or radiation to generate an acid, compounds represented by the following general formulas (ZI), (ZII), and (ZIII) can be exemplified.

In the general formula (ZI), R ₂₀₁ , R ₂₀₂ and R ₂₀₃ each independently represents an organic group.
X ⁻ represents a non-nucleophilic anion, preferably sulfonate anion, carboxylate anion, bis (alkylsulfonyl) amide anion, tris (alkylsulfonyl) methide anion, BF ₄ ⁻ , PF ₆ ⁻ , SbF ₆ ^{— and the} like. Preferably, it is an organic anion containing a carbon atom.
Preferable organic anions include organic anions represented by the following formula.

In the formula, Rc ₁ represents an organic group.
An organic group having 1-30 carbon atoms as the organic group in Rc ₁ is preferably selected, and an alkyl group, an aryl group, or a plurality of these may be a single bond, —O—, —CO ₂ —, —S. _{-, - SO 3 -, -} SO 2 N (Rd 1) - can be exemplified linked group a linking group such as. Rd ₁ represents a hydrogen atom or an alkyl group.
Rc ₃ , Rc ₄ and Rc ₅ represent an organic group. Preferred examples of the organic group for Rc ₃ , Rc ₄ , and Rc ₅ include the same organic groups as those for Rb 1, and most preferably a perfluoroalkyl group having 1 to 4 carbon atoms.
Rc ₃ and Rc ₄ may be bonded to form a ring.
Examples of the group formed by combining Rc ₃ and Rc ₄ include an alkylene group and an arylene group. Preferably, it is a C2-C4 perfluoroalkylene group.
The organic group of Rc ₁ and Rc _{3 to} Rc ₅ is most preferably an alkyl group substituted at the _1- position with a fluorine atom or a fluoroalkyl group, or a phenyl group substituted with a fluorine atom or a fluoroalkyl group. By having a fluorine atom or a fluoroalkyl group, the acidity of the acid generated by light irradiation is increased and the sensitivity is improved. Further, when Rc ₃ and Rc ₄ are bonded to form a ring, the acidity of the acid generated by light irradiation is increased, and the sensitivity is improved.

The carbon number of the organic group as R ₂₀₁ , R ₂₀₂ and R ₂₀₃ is generally 1 to 30, preferably 1 to 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.
Examples of the group formed by combining two of R _{201 to} R ₂₀₃ include an alkylene group (eg, butylene group, pentylene group).
Specific examples of the organic group as R ₂₀₁ , R ₂₀₂ and R ₂₀₃ include corresponding groups in the compounds (Z1-1), (Z1-2) and (Z1-3) 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 examples of the (ZI) component include compounds (Z1-1), (Z1-2), and (Z1-3) described below.

Compound (Z1-1) is at least one of the aryl groups _R 201 _{to R 203} in formula (ZI), arylsulfonium compound, i.e., a compound having 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.
Examples of the arylsulfonium compound include a triarylsulfonium compound, a diarylalkylsulfonium compound, and an aryldialkylsulfonium compound.
The aryl group of the arylsulfonium compound is preferably an aryl group such as a phenyl group or a naphthyl group, or a heteroaryl group such as an indole residue or a pyrrole residue, more preferably a phenyl group or an indole residue. 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 that the arylsulfonium compound has as necessary is preferably a linear, branched or cyclic alkyl group having 1 to 15 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, sec. -Butyl group, t-butyl group, cyclopropyl group, cyclobutyl group, cyclohexyl group and the like can be mentioned.
The aryl group and alkyl group of R _{201 to} R ₂₀₃ are an alkyl group (for example, 1 to 15 carbon atoms), an aryl group (for example, 6 to 14 carbon atoms), an alkoxy group (for example, 1 to 15 carbon atoms), a halogen atom, and a hydroxyl group And may have a phenylthio group as a substituent. Preferred substituents are linear, branched or cyclic alkyl groups having 1 to 12 carbon atoms, linear, branched or cyclic alkoxy groups having 1 to 12 carbon atoms, most preferably alkyl groups having 1 to 4 carbon atoms, It is a C1-C4 alkoxy group. The substituent may be substituted with any one of 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 (Z1-2) will be described.
Compound (Z1-2) is a compound in the case where R _{201 to} R ₂₀₃ in formula (ZI) each independently represents an organic group containing no aromatic ring. Here, the aromatic ring includes an aromatic ring containing a hetero atom.
The organic group not containing an 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 2-oxoalkyl group, an alkoxycarbonylmethyl group, an allyl group, or a vinyl group, more preferably a linear, branched, or cyclic 2-oxoalkyl group, An alkoxycarbonylmethyl group, most preferably a linear, branched 2-oxoalkyl group.

The alkyl group as R ₂₀₁ to R ₂₀₃ may be linear, branched, or cyclic, preferably a linear or branched alkyl group (e.g., methyl group having 1 to 10 carbon atoms, an ethyl group, a propyl Group, butyl group, pentyl group) and cyclic alkyl groups having 3 to 10 carbon atoms (cyclopentyl group, cyclohexyl group, norbornyl group).
The 2-oxoalkyl group as R _{201 to} R ₂₀₃ may be linear, branched or cyclic, and preferably includes a group having> C═O at the 2-position of the above alkyl group. it can.
The alkoxy group in the alkoxycarbonylmethyl group as R ₂₀₁ to R _203, preferred examples include an alkyl group having 1 to 5 carbon atoms (methyl group, ethyl group, propyl group, butyl group, pentyl group).
R _{201 to} R ₂₀₃ may be further substituted with a halogen atom, an alkoxy group (eg, having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, or a nitro group.
Two members out of R _{201 to} R ₂₀₃ may combine 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. Examples of the group formed by combining two of R _{201 to} R ₂₀₃ include an alkylene group (eg, butylene group, pentylene group).

  The compound (Z1-3) is a compound represented by the following general formula (Z1-3), and is a compound having a phenacylsulfonium salt structure.

R _{1c to} R _5c each independently represents a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom.
R _6c and R _7c represent a hydrogen atom or an alkyl group.
Rx and Ry each independently represents an alkyl group, a 2-oxoalkyl group, an alkoxycarbonylmethyl group, an allyl group, or a vinyl group.
Any two or more of R _{1c to} R _5c , 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, a sulfur atom, an ester bond, and an amide bond. May be included.

The alkyl group as R _{1c to} R _{5c may} be linear, branched or cyclic, for example, an alkyl group having 1 to 20 carbon atoms, preferably a linear or branched alkyl having 1 to 12 carbon atoms. Group (for example, methyl group, ethyl group, linear or branched propyl group, linear or branched butyl group, linear or branched pentyl group), C3-C8 cyclic alkyl group (for example, cyclopentyl group, cyclohexyl group) ).
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 either a straight chain of _R 1c _{to R 5c,} branched, cyclic alkyl group, or a linear, branched or cyclic alkoxy group, more preferably the sum of the carbon atoms of _{R 5c} from _{R 1c} 2 to 15 It is. 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 as R _x and R _y include the same alkyl groups as R _{1c to} R _5c .
Examples of the 2-oxoalkyl group include a group having> C═O at the 2-position of the alkyl group as R _{1c to} R _5c .
The alkoxy group in the alkoxycarbonylmethyl group may be the same as the alkoxy group as R _1c to R _5c.
Examples of the group formed by combining R _x and R _y include a butylene group and a pentylene group.

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

In formula _{(ZII), (ZIII),} R 204 ~R 207 each independently represents an alkyl group which may have an optionally substituted aryl group or a substituent.
The aryl group for R _{204 to} R ₂₀₇ is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group.
The alkyl group as R _{204 to} R ₂₀₇ may be linear, branched or cyclic, and is preferably a linear or branched alkyl group having 1 to 10 carbon atoms (for example, methyl group, ethyl group, propyl group). Group, butyl group, pentyl group) and cyclic alkyl groups having 3 to 10 carbon atoms (cyclopentyl group, cyclohexyl group, norbornyl group).
Examples of the substituent that R _{204 to} R ₂₀₇ may have include an alkyl group (for example, 1 to 15 carbon atoms), an aryl group (for example, 6 to 15 carbon atoms), and an alkoxy group (for example, 1 to 15 carbon atoms). ), Halogen atoms, hydroxyl groups, phenylthio groups, and the like.
X ⁻ represents a non-nucleophilic anion, and examples thereof include the same as the non-nucleophilic anion of X ^{− in} formula (I).

  Of the compounds that decompose upon irradiation with actinic rays or radiation that may be used in combination, preferred compounds further include compounds represented by the following general formulas (ZIV), (ZV), and (ZVI). be able to.

In general formulas (ZIV) to (ZVI), Ar ₃ and Ar ₄ each independently represents an aryl group.
R ₂₀₆ represents an alkyl group or a substituted or unsubstituted aryl group.
R ₂₀₇ and R ₂₀₈ each independently represents an alkyl group, an aryl group, or an electron-withdrawing group. R ₂₀₇ is preferably an aryl group.
R ₂₀₈ is preferably an electron-withdrawing group, more preferably a cyano group or a fluoroalkyl group.
A represents an alkylene group, an alkenylene group or an arylene group.

  Of the compounds that decompose upon irradiation with actinic rays or radiation to generate an acid, compounds represented by general formulas (ZI) to (ZIII) are more preferable.

  Moreover, as an acid generator, the compound represented by the following general formula (b-1) or (b-2) is also preferable.

Where
Rb _{1 to} Rb ₃ each independently represents an alkyl group, a cycloalkyl group or an aryl group, and at least one of Rb _{1 to} Rb ₃ represents an aryl group.
Xb represents a fluorinated alkylene group having 2 to 6 carbon atoms.
Yb and Zb each independently represents an alkyl group.

Examples of the alkyl group of Rb _{1 to} Rb ₃ include an alkyl group having 1 to 6 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms, and the cycloalkyl group preferably has 3 to 10 carbon atoms, more preferably It has 4 to 6 carbon atoms.
The fluorinated alkylene group having 2 to 6 carbon atoms of Xb is particularly preferably a perfluoroalkylene group.
The alkyl group for Yb and Zb is preferably a fluorinated alkyl group, preferably having 1 to 6 carbon atoms, more preferably having 1 to 4 carbon atoms.

  Among the compounds that decompose upon irradiation with actinic rays or radiation to generate an acid, examples of particularly preferable compounds are listed below.

  An acid generator can be used individually by 1 type or in combination of 2 or more types. When two or more types are used in combination, it is preferable to combine two types of compounds that generate two types of organic acids that differ in the total number of atoms excluding hydrogen atoms by two or more. The content of the acid generator in the composition is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass, and still more preferably 1 to 7% by mass, based on the total solid content of the resist composition. %.

(C) Resin containing fluorine and / or silicon atom The resist composition of the present invention contains fluorine and / or silicon atom, and contains at least one group selected from the following groups (x) to (z): Resin (also referred to as resin (C)).
(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 polymer.

Specific examples of the repeating unit having an alkali-soluble group (x) are shown below. In the formula, Rx represents H, CH ₃ , CF ₃ or CH ₂ OH.

(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.
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 includes a resin via a linking group such as a repeating unit of an acrylate ester or a methacrylate ester. A polymerization initiator or chain transfer agent having a repeating unit in which an alkali-soluble group is bonded to the main chain or a group (y) that increases solubility in an alkaline developer is introduced at the end of the polymer chain during polymerization. Both are preferable.
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%, still more preferably based on all repeating units in the polymer. 5 to 15 mol%.

  Specific examples of the repeating unit having a group (y) that increases the solubility in an alkali developer include the following lactone structures and structures represented by the general formula (VIII).

The resin (C) of the present invention preferably has a group having a lactone ring. As the group having a lactone ring, any group having a lactone ring can be used, but a group having a 5- to 7-membered ring lactone structure is preferred. A structure in which another ring structure is condensed to form a structure or a spiro structure is preferable. A group having a lactone structure represented by any of the following general formulas (LC1-1) to (LC1-16) is more preferable. Further, a group having a lactone structure may be directly bonded to the main chain. Preferred lactone structures are (LC1-1), (LC1-4), (LC1-5), (LC1-6), (LC1-13), and (LC1-14).

The lactone structure portion 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. n2 represents an integer of 0 to 4. When n2 is 2 or more, a plurality of Rb ₂ may be the same or different, and a plurality of Rb ₂ may be bonded to form a ring.

  Examples of the repeating unit having a group 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 (AI). it can.

In general formula (AI),
R _b0 represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms. Preferable substituents that the alkyl group for R _b0 may have include a hydroxyl group and a halogen atom.

Examples of the halogen atom for R _b0 include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. R _b0 is preferably a hydrogen atom or a methyl group.

_Ab is an alkylene group, a divalent linking group having a monocyclic or polycyclic alicyclic hydrocarbon structure, a single bond, an ether group, an ester group, a carbonyl group, a carboxyl group, or a divalent group obtained by combining these. Represents. A single bond and a linking group represented by -Ab ₁ -CO _2- are preferred.
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 represented by any one of the general formulas (LC1-1) to (LC1-16).

The repeating unit having a lactone structure 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.
Specific examples of the repeating unit having a group having a lactone structure are given below, but the present invention is not limited thereto.

In general formula (VIII):
Z ₂ represents —O— or —N (R ₄₁ ) —. R ₄₁ represents a hydrogen atom, a hydroxyl group, an alkyl group, or —OSO ₂ —R ₄₂ . R ₄₂ represents an alkyl group, a cycloalkyl group or a camphor residue. The alkyl group of R ₄₁ and R ₄₂ may be substituted with a halogen atom (preferably a fluorine atom) or the like.

  Examples of the repeating unit represented by the general formula (VIII) include the following specific examples, but the present invention is not limited thereto.

(Z) The group (acid-decomposable group) that is decomposed by the action of an acid is preferably a group in which a hydrogen atom of an alkali-soluble group such as a —COOH group or —OH group is substituted with a group capable of leaving with an acid.
As the acid eliminable group, there can be, for _{example, -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 , and R ₃₆ and R ₃₉ may be bonded to each other to form a ring.
R _{01 to} R ₀₂ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group or an alkenyl group.
In the present invention, the acid-decomposable group is preferably an acetal group or a tertiary ester group.
The content of the repeating unit having a group (z) that decomposes by the action of an acid in the resin (C) is preferably 1 to 80 mol%, more preferably 10 to 80 mol%, still more preferably based on all repeating units in the polymer. Is 20 to 60 mol%.

When the resist composition of the present invention contains the resin (C), the resin (C) is unevenly distributed on the surface of the photosensitive film, and when the immersion medium is water, the photosensitive film for water when the photosensitive film is used. The receding contact angle of the surface can be improved, and the immersion water followability can be improved. As the resin (C), any resin can be used as long as the receding contact angle on the surface can be improved by addition, but a resin having at least one of a fluorine atom and a silicon atom is preferable. The receding contact angle of the photosensitive film is preferably 60 ° to 90 °, more preferably 70 ° or more.
The addition amount of the resin (C) can be appropriately adjusted and used so that the receding contact angle of the photosensitive film falls within the above range, but is 0.1 to 10% by mass based on the total solid content of the photosensitive composition. It is preferable that it is 0.1 to 5% by mass.
The resin (C) is ubiquitous at the interface as described above, but unlike the surfactant, it does not necessarily have a hydrophilic group in the molecule, and the polar / nonpolar substance is mixed uniformly. You don't have to contribute.

  The resin (C) is preferably an alkali-soluble resin containing an alkyl group having 1 to 4 carbon atoms having a fluorine atom, a cycloalkyl group having a fluorine atom, or an aryl group having a fluorine atom.

  The resin (C) preferably has an alcoholic hydroxyl group, and the alcohol moiety of the alcoholic hydroxyl group is preferably a fluorinated alcohol.

  Resin (C) is a resin (C1) having an alicyclic structure and at least one of a fluorine atom and a silicon atom, a repeating unit having at least one of a fluorine atom and a silicon atom in a side chain, and an unsubstituted side chain It is preferably at least one of resins (C2) containing a repeating unit having an alkyl group.

The resin (C) is preferably a hydrophobic resin (HP). The hydrophobic resin (HP) can be suitably used as a top coat.
The fluorine atom or silicon atom in the resin (HP) may be contained in the main chain of the resin or may be substituted with a side chain.
The resin (HP) is preferably soluble in an alkali developer.

“Hydrophobic resin” refers to a resin that, when added to the photosensitive film, contributes to an improvement in the contact angle of water on the surface of the photosensitive film.
The hydrophobic resin may be anything as long as the receding contact angle of the surface is improved by addition, but is preferably a resin having at least one of a fluorine atom and a silicon atom. The forward contact angle of the photosensitive film is preferably adjusted to 70 ° to 120 °, more preferably 75 ° to 100 °, when immersion exposure is applied. The receding contact angle is preferably adjusted to 60 ° to 100 °, more preferably 70 ° to 90 °. The amount of the hydrophobic resin (HP) added can be adjusted as appropriate so that the receding contact angle of the photosensitive film falls within the above range, but it is 0.1 to 10 mass based on the total solid content of the photosensitive composition. %, And more preferably 0.1 to 5% by mass.
It is preferable to contribute to improving the receding contact angle with a smaller addition amount, and the glass transition point (Tg) of the resin is preferably in the range of 50 ° C to 200 ° C.
Moreover, it is preferable that it is solid at normal temperature (25 degreeC).
The advancing contact angle and receding contact angle defined here are advancing and receding contact angles measured by the expansion and contraction method. Specifically, 36 μL of water droplets with a syringe on a positive resist composition prepared on a silicon wafer. Then, discharge or suction is performed at a speed of 6 μL / second, and the contact angle during discharge / suction shows a stable value.
Hydrophobic resins are often ubiquitous at the interface, but unlike the surfactant (E), it is not always necessary to have a hydrophilic group in the molecule, contributing to uniform mixing of polar / nonpolar substances. You don't have to.
In addition, “soluble in an alkali developer” means that the amount of the hydrophobic resin film dissolved in a 2.38 wt% tetramethylammonium hydroxide aqueous solution at 23 ° C. is 50 nm or more when integrated for 30 seconds from the start of development. Say that. In order to be soluble in an alkali developer, it is necessary that the photosensitive resin film has an alkali-soluble group in the development step.
The alkali-soluble group may be previously contained in the resin, or may be generated by the action of an acid between the exposure and development steps, or may react with an alkali developer to generate an alkali-soluble group. .

The resin (HP) is preferably a resin having, as a partial structure having a fluorine atom, an alkyl group having a fluorine atom, a cycloalkyl group having a fluorine atom, or an aryl group having a fluorine atom.
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.

  A general formula of an alkyl group having a fluorine atom, a cycloalkyl group having a fluorine atom, or an aryl group having a fluorine atom is shown below, but the present invention is not limited thereto.

In general formulas (F2) to (F4),
R _{57 to} R ₆₈ each independently represents 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 1 carbon atom). ~ 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 , 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.

Hereinafter, the specific example of the repeating unit containing group represented by general formula (F2)-(F4) is shown. In the formula, X ₁ represents a hydrogen atom, —CH ₃ , —F, or —CF ₃ . X ₂ is, -F, or represents a -CF _3.

The resin (HP) 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 general formulas (CS-1) to (CS-3),
R _{12 to} R ₂₆ each independently represents a linear or branched alkyl group (preferably having 1 to 20 carbon atoms) or a cycloalkyl group (preferably having 3 to 20 carbon atoms).
L < ₃ > -L < ₅ > represents a single bond or a bivalent coupling group. As the divalent linking group, an alkylene group, a phenyl 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.
A specific example is shown below. In the formula, X ₁ represents a hydrogen atom, —CH ₃ , —F, or —CF ₃ .

  Furthermore, the resin (HP) may have a repeating unit represented by the following general formula (III).

In general formula (III):
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 resin (HP) has a fluorine atom, the content of the fluorine atom is preferably 5 to 80% by mass and more preferably 10 to 80% by mass with respect to the molecular weight of the resin (HP). Moreover, it is preferable that the repeating unit containing a fluorine atom is 10-100 mass% in resin (HP), and it is more preferable that it is 30-100 mass%.

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

  As with the acid-decomposable resin (A), the resin (HP) 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.

  As the resin (HP), various commercially available products can be used, or they 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 that used in the resist composition of the present invention. Thereby, generation | occurrence | production of the particle at the time of a preservation | save 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. The concentration of the reaction is 5 to 50% by mass, preferably 30 to 50% by mass. The reaction temperature is usually 10 ° C to 150 ° C, preferably 30 ° C to 120 ° C, more preferably 60-100 ° 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. 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 completion of the radical polymerization reaction, a solvent in which the polymer is hardly soluble or insoluble is brought into contact, the resin is precipitated (step a), the resin is separated from the solution (step b), and dissolved again in the solvent. (Step c), and then contact 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 5 times or less volume). This may be a method including precipitating a resin solid (step d) and separating the precipitated resin (step e).

  Specific examples of the resin (C) are shown below. The following table shows the molar ratio of 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.

In order to prevent the resist film from coming into direct contact with the immersion liquid between the resist film made of the resist composition of the present invention and the immersion liquid, an immersion liquid hardly soluble film (hereinafter also referred to as “top coat”) is provided. It may be provided. 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 top coat is preferably a polymer that does not contain abundant aromatics. Specifically, the polymer contains a hydrocarbon polymer, an acrylate polymer, polymethacrylic acid, polyacrylic acid, polyvinyl ether, and silicon. Examples thereof include a polymer and a fluorine-containing polymer. The aforementioned hydrophobic resin (HP) is also suitable as a top coat. From the viewpoint of contaminating the optical lens when impurities are eluted from the top coat into the immersion liquid, it is preferable that the residual monomer component of the polymer contained in the top coat is small.

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 film 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 film 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 film.
The resolution is improved when there is no difference in refractive index between the top coat and the immersion liquid. In the case of using water as the immersion liquid in an ArF excimer laser (wavelength: 193 nm), the top coat for ArF immersion exposure is preferably close to the refractive index of the immersion liquid. From the viewpoint of making the refractive index close to the immersion liquid, it is preferable to have fluorine atoms in the topcoat. A thin film is more preferable from the viewpoint of transparency and refractive index.

  The top coat is preferably not mixed with the resist film and further not mixed with the immersion liquid. From this point of view, when the immersion liquid is water, the solvent used for the top coat is preferably a water-insoluble medium that is hardly soluble in the solvent used for the resist composition. Furthermore, when the immersion liquid is an organic solvent, the topcoat may be water-soluble or water-insoluble.

(D) Solvent The resist composition of the present invention is used by dissolving the above components in a predetermined solvent.
Examples of the solvent include an alkylene glycol monoalkyl ether carboxylate, an alkylene glycol monoalkyl ether, an alkyl lactate ester, an alkyl alkoxypropionate, a cyclic lactone having 4 to 10 carbon atoms, and a ring having 4 to 10 carbon atoms. And organic solvents such as monoketone compounds, alkylene carbonates, alkyl alkoxyacetates, and alkyl pyruvates.

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 having 4 to 10 carbon atoms include β-propiolactone, β-butyrolactone, γ-butyrolactone, α-methyl-γ-butyrolactone, β-methyl-γ-butyrolactone, γ-valerolactone, γ- Caprolactone, γ-octanoic lactone, and α-hydroxy-γ-butyrolactone are preferred.

  Examples of the monoketone compound having 4 to 10 carbon atoms 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- Xen-2-one, 3-penten-2-one, cyclopentanone, 2-methylcyclopentanone, 3-methylcyclopentanone, 2,2-dimethylcyclopentanone, 2,4,4-trimethylcyclopenta Non, cyclohexanone, 3-methylcyclohexanone, 4-methylcyclohexanone, 4-ethylcyclohexanone, 2,2-dimethylcyclohexanone, 2,6-dimethylcyclohexanone, 2,2,6-trimethylcyclohexanone, cycloheptanone, 2-methylcyclo Preferred are heptanone and 3-methylcycloheptanone.

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 preferred, and propylene glycol monomethyl ether acetate, ethyl ethoxypropionate. 2-heptanone is most preferred.

In the present invention, two or more kinds of mixed solvents containing propylene glycol monomethyl ether acetate are particularly preferable.
Furthermore, it is more preferable to use two or more kinds of mixed solvents containing ethyl lactate and propylene glycol monomethyl ether acetate.

  The mixing ratio (mass) of the solvent containing a hydroxyl group and the solvent not containing a hydroxyl group is 1/99 to 99/1, preferably 10/90 to 90/10, more preferably 20/80 to 60/40. . A mixed solvent containing 50% by weight or more of a solvent not containing a hydroxyl group is particularly preferred from the viewpoint of coating uniformity.

(E) Basic compound The positive resist composition of the present invention preferably contains (E) a basic compound in order to reduce a change 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 formulas (A) to (E),
R ²⁰⁰ , R ²⁰¹ and R ²⁰² may be the same or different and are a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms. Here, R ²⁰¹ and R ²⁰² may combine with each other to form a ring.

The alkyl group may be unsubstituted or may have a substituent. Examples of the alkyl group having a substituent include an aminoalkyl group having 1 to 20 carbon atoms, a hydroxyalkyl group having 1 to 20 carbon atoms, Or a C1-C20 cyanoalkyl group is preferable.
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 groups in these general formulas (A) to (E) are more preferably unsubstituted.

Examples of basic compounds include substituted or unsubstituted primary, secondary, and tertiary aliphatic amines, aromatic amines, heterocyclic amines, amide derivatives, imide derivatives, and cyano groups. Examples thereof include nitrogen-containing compounds. Of these, aliphatic amines, aromatic amines, and heterocyclic amines are preferable. Preferred substituents that may be present are an amino group, an alkyl group, an alkoxy group, an acyl group, an acyloxy group, an aryl group, an aryloxy group, a nitro group, a cyano group, an ester group, and a lactone group.
These basic compounds are used alone or in combination of two or more.
In the resist composition of the present invention, the basic compound (E) is preferably a triethanolamine compound.

  The usage-amount of a basic compound is 0.001-10 mass% normally on the basis of 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.

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

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 (manufactured by Dainippon Ink & Chemicals, Inc.), Surflon S-382, SC101, 102, 103, 104, 105, 106 (manufactured by Asahi Glass Co., Ltd.), Troisol S-366 (Manufactured by Troy Chemical Co., Ltd.), GF-300, GF-150 (manufactured by Toa Gosei Chemical Co., Ltd.), Surflon S-393 (manufactured by Seimi Chemical Co., Ltd.), F-top EF121, EF122A, EF122B, RF122C, EF125M , EF135M, EF351, 352, EF801, EF8 2, EF601 (manufactured by Gemco), PF636, PF656, PF6320, PF6520 (manufactured by OMNOVA), FTX-204D, 208G, 218G, 230G, 204D, 208D, 212D, 218, 222D (manufactured by Neos) Fluorine-based surfactants or silicon-based surfactants such as 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 allyl 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 monopal Te - 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 0.01 to 10% by mass, more preferably 0.1 to 5% by mass, based on the total amount of the positive resist composition (excluding the solvent).

  These surfactants may be added alone or in some combination.

  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).

(G) Alkali-soluble resin The positive resist composition of the present invention may further contain an acid-decomposable group, (G) a resin that is insoluble in water and soluble in an alkaline developer, This improves the sensitivity.
In the present invention, novolak resins having a molecular weight of about 1000 to 20000 and polyhydroxystyrene derivatives having a molecular weight of about 3000 to 50000 can be used as such an alkali-soluble resin. However, they absorb light of 250 nm or less. Since it is large, it is preferable to use it by partially hydrogenating or using it in an amount of 30% by weight or less of the total resin amount.
A resin containing a carboxyl group as an alkali-soluble group can also be used. The resin containing a carboxyl group preferably has a monocyclic or polycyclic alicyclic hydrocarbon group for improving dry etching resistance. Specifically, a methacrylic acid ester and (meth) acrylic acid copolymer having an alicyclic hydrocarbon structure that does not exhibit acid decomposability, or a (meth) acrylic acid ester having an alicyclic hydrocarbon group having a carboxyl group at the terminal And the like.

(H) Carboxylic acid onium salt The positive resist composition in the present invention may contain (H) a carboxylic acid onium salt. Examples of the carboxylic acid onium salt include a carboxylic acid sulfonium salt, a carboxylic acid iodonium salt, and a carboxylic acid ammonium salt. In particular, the (H) carboxylic acid onium salt is preferably an iodonium salt or a sulfonium salt. Furthermore, it is preferable that the carboxylate residue of the (H) carboxylic acid onium salt of the present invention does not contain an aromatic group or a carbon-carbon double bond. As a particularly preferable anion moiety, a linear, branched, monocyclic or polycyclic alkylcarboxylic acid anion having 1 to 30 carbon atoms is preferable. More preferably, an anion of a carboxylic acid in which some or all of these alkyl groups are fluorine-substituted is preferable. The alkyl chain may contain an oxygen atom. This ensures transparency with respect to light of 220 nm or less, improves sensitivity and resolution, and improves density dependency and exposure margin.

  Fluorine-substituted carboxylic acid anions include fluoroacetic acid, difluoroacetic acid, trifluoroacetic acid, pentafluoropropionic acid, heptafluorobutyric acid, nonafluoropentanoic acid, perfluorododecanoic acid, perfluorotridecanoic acid, perfluorocyclohexanecarboxylic acid, 2 , 2-bistrifluoromethylpropionic acid anion and the like.

  These (H) carboxylic acid onium salts can be synthesized by reacting sulfonium hydroxide, iodonium hydroxide, ammonium hydroxide and carboxylic acid with silver oxide in a suitable solvent.

  The content of (H) carboxylic acid onium salt in the composition is suitably from 0.1 to 20% by weight, preferably from 0.5 to 10% by weight, more preferably 1%, based on the total solid content of the composition. -7% by mass.

Other Additives In the positive resist composition of the present invention, if necessary, a dye, a plasticizer, a photosensitizer, a light absorber, and a compound that promotes solubility in a developer (for example, a molecular weight of 1000 or less) A phenol compound, an alicyclic compound having a carboxyl group, or an aliphatic compound).

Such phenolic compounds having a molecular weight of 1000 or less can be obtained by referring to, for example, the methods described in JP-A-4-1222938, JP-A-2-28531, US Pat. No. 4,916,210, European Patent 219294, etc. It can be easily synthesized by those skilled in the art.
Specific examples of alicyclic or aliphatic compounds having a carboxyl group include carboxylic acid derivatives having a steroid structure such as cholic acid, deoxycholic acid, lithocholic acid, adamantane carboxylic acid derivatives, adamantane dicarboxylic acid, cyclohexane carboxylic acid, cyclohexane Examples thereof include, but are not limited to, dicarboxylic acids.

[Physical properties of resist composition]
The positive resist composition of the present invention is preferably used at a film thickness of 30 to 250 nm, more preferably at a film thickness of 30 to 200 nm, from the viewpoint of improving resolution. Such a film thickness can be obtained by setting the solid content concentration in the positive resist composition to an appropriate range to give an appropriate viscosity and improving the coating property and film forming property.
The total solid concentration in the positive resist composition is generally 1 to 10% by mass, more preferably 1 to 8% by mass, and still more preferably 1.0 to 7.0% by mass.

[Pattern formation method]
The positive resist composition of the present invention is used by dissolving the above components in a predetermined organic solvent, preferably the mixed solvent, filtering the solution, and then applying the solution on a predetermined support as follows. The filter used for filter filtration is preferably made of polytetrafluoroethylene, polyethylene, or nylon of 0.1 microns or less, more preferably 0.05 microns or less, and still more preferably 0.03 microns or less.

For example, a positive resist composition is coated on a substrate (eg, silicon / silicon dioxide coating) used in the manufacture of precision integrated circuit elements by a suitable coating method such as a spinner or a coater, and dried to form a photosensitive film. Form.
The photosensitive film is irradiated with actinic rays or radiation through a predetermined mask, preferably baked (heated), developed and rinsed. Thereby, a good pattern can be obtained.

Examples of the actinic ray or radiation include infrared light, visible light, ultraviolet light, far ultraviolet light, X-ray, electron beam, etc., but preferably far ultraviolet light having a wavelength of 250 nm or less, more preferably 220 nm or less. Specifically, KrF excimer laser (248 nm), ArF excimer laser (193 nm), F ₂ excimer laser (157 nm), X-ray, electron beam, etc., more preferably light having a wavelength of 1 nm to 200 nm, particularly ArF Excimer laser, F ₂ excimer laser, EUV (13 nm), and electron beam are preferable.

In the development step, an alkaline developer is used as follows. 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 added in appropriate amounts to the alkaline developer.
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.
Furthermore, alcohols and surfactants can be added in appropriate amounts to the alkaline aqueous solution.
As the rinsing liquid, pure water can be used, and an appropriate amount of a surfactant can be added.
Further, after the development process or the rinsing process, a process of removing the developer or the rinsing liquid adhering to the pattern with a supercritical fluid can be performed.

Exposure (immersion exposure) may be performed by filling a liquid (immersion medium) having a higher refractive index than air between the resist film and the lens during irradiation with actinic rays or radiation. Thereby, resolution can be improved. As the immersion medium to be used, any liquid can be used as long as it has a higher refractive index than air, but pure water is preferred. Further, an overcoat layer may be further provided on the photosensitive film so that the immersion medium and the photosensitive film do not come into direct contact with each other during the immersion exposure. Thereby, the elution of the composition from the photosensitive film to the immersion medium is suppressed, and development defects are reduced.

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. By adding an alcohol having a refractive index substantially equal to that of water, even if the alcohol component in water evaporates and the content concentration changes, an advantage that the change in the refractive index of the entire liquid can be made extremely small can be obtained. On the other hand, when an opaque substance or impurities whose refractive index is significantly different from that of water are mixed with respect to 193 nm light, the optical image projected on the resist is distorted. Therefore, distilled water is preferable as the water to be used. Further, pure water filtered through an ion exchange filter or the like may be used.

The electrical resistance of water is desirably 18.3 MQcm or more, the TOC (organic substance concentration) is desirably 20 ppb or less, and deaeration treatment is desirably performed.
Moreover, it is possible to improve lithography performance by increasing the refractive index of the immersion liquid. From such a viewpoint, an additive that increases the refractive index may be added to water, or heavy water (D ₂ O) may be used instead of water.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, the content of this invention is not limited by this.

Synthesis Example-Preparation of Resin (C) Heptafluorobutyl methacrylate and t-butyl methacrylate were charged at a ratio (molar ratio) of 50/50 and dissolved in cyclohexanone to prepare 450 g of a solution having a solid content concentration of 22%. To this solution, 5 mol% of a polymerization initiator V-601 manufactured by Wako Pure Chemical Industries, Ltd. was added, and this was added dropwise to 50 mL of cyclohexanone heated to 80 ° C. over 2 hours in a nitrogen atmosphere. The reaction liquid was stirred for 2 hours after completion | finish of dripping, and the reaction liquid (HR-1) was obtained. After completion of the reaction, the reaction solution (HR-1) was cooled to room temperature, crystallized in 10 volumes of methanol, and the precipitated white powder was collected by filtration to recover the target resin (HR-1).
The polymer composition ratio determined from 1H-NMR was 50/50 (molar ratio). Moreover, the weight average molecular weight of standard polystyrene conversion calculated | required by GPC measurement was 8800, and dispersion degree was 2.1.
Similarly, other resins (C) were prepared.

Example of Resin (A) Synthesis of 0.4 mol of 2-ethyl-2-adamantyl methacrylate, 0.4 mol of α- (γ-butyrolactone) methacrylate, and 0.2 mol of 3-hydroxy-1-adamantyl methacrylate, 600 ml of cyclobentanone Into this, 0.1 mol of AIBN was added and dissolved. The resulting solution was heated at 65-70 ° C. for 3 hours. The obtained reaction solution was poured into 3 L of well-stirred isopropanol, and the precipitated solid was separated by filtration. The obtained solid was dissolved in 600 ml of THF, poured into 3 L of well-stirred methanol, and the precipitated solid was separated by filtration and dried to obtain the following resin 1.
Similarly, resins 2 to 6 were synthesized. The structure, composition ratio, weight average molecular weight (Mw), and dispersity (Mw / Mn) are shown below.

<Registration adjustment>
The components shown in Table 2 below were dissolved in a solvent, and a solution with a solid concentration of 7% by mass was prepared for each, and this was filtered through a 0.1 μm polyethylene filter to prepare a positive resist solution. The prepared positive resist composition was evaluated by the following method, and the results are shown in the following table.
In addition, about each component in a table | surface, ratio when using two or more is a mass ratio.
In Table 2, Example 1,4～11,1 3-20, respectively, shall be read as reference example 1,4～11,1 3-20.

<Exposure evaluation: Water mark>
An organic antireflection film ARC29A (Nissan Chemical Co., Ltd.) was applied on a silicon wafer and baked at 205 ° C. for 60 seconds to form a 78 nm antireflection film. The positive resist composition prepared thereon was applied and baked at 110 ° C. for 60 seconds to form a 150 nm resist film. The obtained wafer was subjected to pattern exposure using an ArF excimer laser immersion scanner (NA 0.85, scan speed 500 mm / s). Ultra pure water was used as the immersion liquid. Thereafter, heating was performed at 110 ° C. for 60 seconds, followed by development with an aqueous tetramethylammonium hydroxide solution (2.38 mass%) for 30 seconds, rinsing with pure water, and spin drying to obtain a resist pattern. Thereafter, the defect distribution in the wafer shape was detected with KLA2360 (manufactured by KLA), and the shape of the defect was observed using SEMVision (manufactured by AMAT).
A round defect having a diameter of about 1 μm to 5 μm as shown in FIG.

<Exposure evaluation: film reduction margin>
An organic antireflection film ARC29A (Nissan Chemical Co., Ltd.) was applied on a silicon wafer and baked at 205 ° C. for 60 seconds to form a 78 nm antireflection film. The positive resist composition prepared thereon was applied and baked at 110 ° C. for 60 seconds to form a 150 nm resist film. The obtained wafer was subjected to pattern exposure using an ArF excimer laser immersion scanner (NA 0.85). Ultra pure water was used as the immersion liquid. Thereafter, heating was performed at 110 ° C. for 60 seconds, followed by development with an aqueous tetramethylammonium hydroxide solution (2.38 mass%) for 30 seconds, rinsing with pure water, and spin drying to obtain a resist pattern. At this time, due to the exposure amount (Eo) for resolving the 75 nm L / S (line and space) pattern to 1: 1 and the overexposure amount, the rectangular shape of the head shape of the pattern is lost due to the film starting to dissolve. The exposed exposure amount (ELoss) was obtained, and the film reduction margin (overexposure margin) was calculated from the following formula.
Film reduction margin (%) = (ELoss−Eo) / Eo × 100

  The symbols in Table 2 are as follows. The symbols in the table are as follows.

The acid generator corresponds to that exemplified above.
N-1: N, N-dibutylaniline N-2: N, N-dihexylaniline N-3: 2,6-diisopropylaniline N-4: tri-n-octylamine N-5: N, N-dihydroxyethyl Aniline N-6: 2,4,5-triphenylimidazole N-7: Triethanolamine

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)
W-4: Troisol S-366 (manufactured by Troy Chemical Co., Ltd.)
W-5: PF656 (manufactured by OMNOVA, fluorine-based)
W-6: PF6320 (manufactured by OMNOVA, fluorine-based)

SL-1: Cyclohexanone SL-2: Propylene glycol monomethyl ether acetate SL-3: Ethyl lactate SL-4: Propylene glycol monomethyl ether SL-5: γ-butyrolactone SL-6: Propylene carbonate

Claims (19)

(A) The repeating unit (a1) having a structure selected from the following general formulas (a1-1) and (a1-3), the repeating unit (a2) represented by the following general formula (a2), and the following general formula A resin containing a repeating unit (a3) having a structure selected from (a3-1) to (a3-4) and having an increased dissolution rate in an alkali developer by the action of an acid;
(B) a compound that generates an acid upon irradiation with an actinic ray or radiation,
(C) Resin containing fluorine and / or silicon atom and containing at least one group selected from the group of groups represented by the following ( y ) , (z) , (f) and the following general formula (F3) And (D) a solvent,
The positive resist composition characterized by containing.
(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 ,
(F) a C1-C4 alkyl group having a fluorine atom, a cycloalkyl group having a fluorine atom, or an aryl group having a fluorine atom.


Where
R represents a hydrogen atom, a halogen atom or an alkyl group.
R ′ represents an acid-decomposable group.
R ₁₂ and R ₁₃ each independently represents a hydrogen atom, a methyl group, an ethyl group or a propyl group.
R ₁₄ represents an alicyclic group.
n represents an integer of 0 to 5.

In general formula (F3),
R _{62 to} R ₆₄ each independently represents a hydrogen atom, a fluorine atom or an alkyl group. However, at least one of R _{62 to} R ₆₄ represents an alkyl group in which at least one hydrogen atom is substituted with a fluorine atom. The positive resist composition according to claim 1, wherein the resin (A) further contains a repeating unit (a4) having any one of the following structures (a4-1) to (a4-3).


Where
R represents a hydrogen atom, a halogen atom or an alkyl group. The positive resist composition according to claim 1, wherein the resin (C) is a resin containing a group represented by the general formula (F3).   3. The positive electrode according to claim 1, wherein the resin (C) is a resin containing a group that is decomposed by the action of an alkali developer (y) and increases the solubility in the alkali developer. Type resist composition.   5. The positive resist composition according to claim 4, wherein the group (y) that is decomposed by the action of the alkali developer and increases the solubility in the alkali developer is a group having a lactone structure. .   The positive resist composition according to claim 1, wherein the resin (C) is a resin containing a group that is decomposed by the action of (z) acid. The group (z) decomposed by the action of the acid is a group in which the hydrogen atom of the —COOH group is substituted with a group capable of leaving with an acid represented by —C (R ₃₆ ) (R ₃₇ ) (R ₃₈ ). The positive resist composition according to claim 6, wherein the positive resist composition is present.
(In the above formula, R _{36 to} R ₃₈ each independently represents an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group or an alkenyl group, and R ₃₆ and R ₃₇ are bonded to each other to form a ring. May be.) The positive resist composition according to claim 1, wherein the resin (C) has at least one repeating unit having a lactone group. The resin (C) is an alkali-soluble compound containing (f) an alkyl group having 1 to 4 carbon atoms having a fluorine atom, a cycloalkyl group having a fluorine atom, or an aryl group having a fluorine atom. The positive resist composition according to claim 1 or 2. 3. The positive resist composition according to claim 1, wherein the resin (C) has an alcoholic hydroxyl group, and the alcohol portion of the alcoholic hydroxyl group is a fluorinated alcohol.   The positive resist composition according to claim 1, wherein the content of the resin (C) is 0.1 to 10% by mass based on the total solid content of the resist composition. object.   The positive resist composition according to claim 11, wherein the content of the resin (C) is 0.1 to 5% by mass based on the total solid content of the resist composition.   The positive resist composition according to claim 1, wherein the solvent (D) is a mixed solvent of two or more types containing propylene glycol monomethyl ether acetate.   The positive resist composition according to claim 1, wherein the solvent (D) is a mixed solvent of two or more containing ethyl lactate and propylene glycol monomethyl ether acetate.   The positive resist composition according to claim 1, further comprising (E) a basic compound. The positive resist composition according to claim 1, wherein the compound (B) is a compound represented by the following general formula (b-1).


In the above general formula,
Rb _{1 to} Rb ₃ each independently represents an alkyl group, a cycloalkyl group or an aryl group, and at least one of Rb _{1 to} Rb ₃ represents an aryl group.
Xb represents a fluorinated alkylene group having 2 to 6 carbon atoms.   The positive resist composition according to claim 1, wherein the compound (B) has a triphenylsulfonium cation structure.   A resist film formed from the positive resist composition according to claim 1.   A pattern forming method comprising: forming a resist film from the resist composition according to claim 1, exposing and developing the resist film.