JP5565042B2 - Upper layer film forming composition and photoresist pattern forming method - Google Patents

Description

The present invention protects a photoresist film during immersion exposure used for lithography miniaturization, and forms an upper film that protects a lens of a projection exposure apparatus by suppressing elution of components of the photoresist film. The present invention relates to a composition for forming an upper layer film useful for the present invention and a method for forming a photoresist pattern using the composition for forming an upper layer film.

When manufacturing a semiconductor element or the like, a reticle pattern as a photomask is applied to each shot region on a wafer coated with a photoresist film (hereinafter sometimes referred to as “photoresist”) via a projection optical system. A stepper type or step-and-scan type projection exposure apparatus for transferring is used. The resolution of the projection optical system provided in the projection exposure apparatus becomes higher as the exposure wavelength used is shorter and the numerical aperture of the projection optical system is larger. For this reason, with the miniaturization of integrated circuits, the exposure wavelength, which is the wavelength of radiation used in the projection exposure apparatus, has become shorter year by year, and the numerical aperture of the projection optical system has also increased.

In addition, when performing exposure, the depth of focus is important as well as the resolution. The resolution R and the depth of focus δ are each expressed by the following equations. In order to obtain the same resolution R, it is possible to obtain a large depth of focus δ by using radiation having a short wavelength. R = k1 · λ / NA (i) δ = k2 · λ / NA ² (ii) (where λ is the exposure wavelength, NA is the numerical aperture of the projection optical system, and k1 and k2 are both process coefficients)

A photoresist film is formed on the exposed wafer surface, and the pattern is transferred to the photoresist film. In a conventional projection exposure apparatus, a space in which a wafer is placed is filled with air or nitrogen. At this time, when the space between the wafer and the lens of the projection exposure apparatus is filled with a medium having a refractive index n, the resolution R and the depth of focus δ are expressed by the following equations. R = k1 · (λ / n) / NA (iii) δ = k2 · nλ / NA ² (iv)

For example, when water is used as the medium in the ArF process, when the refractive index n = 1.44 in water of light having a wavelength of 193 nm is used, the resolution R is smaller than that in exposure using air or nitrogen as a medium. 69.4% (R = k1 · (λ / 1.44) / NA), and the focal depth is 144% (δ = k2 · 1.44λ / NA ² ).

In this way, the projection exposure method capable of shortening the wavelength of radiation for exposure and transferring a finer pattern is called immersion exposure, which is indispensable for lithography miniaturization, particularly lithography of several tens of nanometers. The projection exposure apparatus is also known (see Patent Document 1).

In the immersion exposure method using water as a medium during immersion exposure, the photoresist film coated and formed on the wafer and the lens of the projection exposure apparatus are in contact with water, respectively. Therefore, water may penetrate into the photoresist film and the resolution of the photoresist may be reduced. In addition, the lens of the projection exposure apparatus may contaminate the lens surface due to elution of components constituting the photoresist into water.

For this reason, there is a method of forming an upper layer film (protective film) on the photoresist film for the purpose of blocking the photoresist film from a medium such as water. However, the upper layer film can be formed on the photoresist film with (1) sufficient transparency to the wavelength of radiation, and (2) almost no intermixing with the photoresist film. (3) It is possible to maintain a stable coating without leaching into a medium such as water at the time of immersion exposure, and (4) it is easily dissolved in an alkaline solution or the like as a developer. Is required. Patent Documents 2 and 3 are disclosed as related prior art documents.

In the immersion exposure process, when exposure is performed using a scanning immersion exposure machine, the exposure speed decreases unless the immersion liquid moves following the movement of the lens. Concerned about giving. When the immersion liquid is water, it is desirable that the immersion upper layer film be hydrophobic (that is, have a high receding contact angle). Patent Document 4 discloses a composition for forming a liquid immersion upper layer film to which a polymer having high water repellency is added.

Japanese Patent Laid-Open No. 11-176727 JP 2005-264131 A JP 2006-64711 A International Publication No. 08/047678 Pamphlet

However, when scanning exposure is performed on an upper layer film having high water repellency, bubbles are generated, and bubble defects caused by transfer of the bubbles to the resist pattern after development may become a problem. This is considered to be mainly caused by biting bubbles at the interface between the immersion liquid and the upper film because the advancing contact angle is increased when the receding contact angle of the upper film is increased. Therefore, in order to cope with high-speed scanning exposure, the upper layer film is further improved so as to increase the receding contact angle (for example, 75 ° or more) but not to increase the advancing contact angle (for example, 95 ° or less). Is required.

The present invention has been made in view of such problems of the prior art, and the problem is that the backward contact angle and the forward contact angle have an appropriate balance, and the scanning speed is high ( For example, even if it is 700 mm / s), the composition for forming an upper layer film that can form a liquid immersion upper layer film that can suppress water residue and can also suppress the generation of bubbles at the interface between the immersion liquid and the upper layer film. And an effective polymer as a component of the composition for forming a liquid immersion upper layer film.

The composition for forming an upper layer film of the present invention has sufficient permeability to exposure light, is formed on the photoresist film with little intermixing with the photoresist film, and is applied to a medium such as water during immersion exposure. It is possible to form an upper layer film having a sufficiently high receding contact angle and a sufficiently low advancing contact angle while maintaining a highly stable resist film that is hardly eluted and forming a high-resolution resist pattern. There is an effect. Such an upper layer film-forming composition can effectively suppress the occurrence of defects such as watermark defects and bubble defects even when the scanning speed is high (for example, 700 mm / s).

BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out the present invention will be described below, but the present invention is not limited to the following embodiment, and is based on the ordinary knowledge of those skilled in the art without departing from the gist of the present invention. It should be understood that modifications and improvements as appropriate to the following embodiments also fall within the scope of the present invention.

[1] Upper layer film forming composition: The upper layer film forming composition of the present invention is a photo formed by a photoresist composition containing a polymer (X) containing an acid dissociable group and an acid generator (Y). An upper layer film composition for immersion, which is used for forming an upper layer film on the surface of a resist film, and contains a polymer (A) containing a repeating unit having a hydrocarbon group .

The upper layer film formed from the above upper layer film-forming composition has sufficient permeability to exposure light, is formed on the photoresist film with little intermixing with the photoresist film, and is subjected to water exposure during immersion exposure. There is an advantage in that it has a sufficiently high receding contact angle and a sufficiently low advancing contact angle while maintaining a stable coating that hardly dissolves in a medium such as the above, and forming a high-resolution resist pattern.

The upper layer film-forming composition is used for forming an upper layer film on the surface of a photoresist film. Preferably, the photoresist film comprises a polymer (X) containing an acid dissociable group and It is formed by a photoresist composition containing an acid generator (Y).

Furthermore, the said polymer (X) contains the repeating unit containing an acid dissociable group, and this repeating unit is 30-60 mol% with respect to all the repeating units of polymer (X). It is preferable. If the repeating unit is less than 30 mol%, the resolution as a resist may deteriorate. On the other hand, if the above repeating unit is more than 60 mol%, the resist film thickness after peeling off the upper layer film may be extremely reduced.

Examples of the polymer (X) include a resin containing the following repeating unit (M-1), the following repeating unit (M-2), and the following repeating unit (M-3), and the following repeating unit (M-1). ), A resin containing the following repeating unit (M-2), and the following repeating unit (M-4), the following repeating unit (M-1), the following repeating unit (M-3), and the following repeating unit (M- Examples thereof include a resin containing 5).

The acid generator (Y) generates an acid from the acid generator by radiation irradiation (exposure), and has an acid dissociation property that protects acidic groups (for example, carboxyl groups) of the resin by the action of the generated acid. The group dissociates and the acidic group is exposed.

Examples of the acid generator (Y) include triphenylsulfonium / nonafluoro-n-butanesulfonate, 4-cyclohexylphenyl / diphenylsulfonium / nonafluoro-n-butanesulfonate, and 1- (4-n-butoxynaphthalene-1- Yl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, triphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1,2,2-tetrafluoroethanesulfonate, 1 -(4-n-butoxynaphthyl) tetrahydrothiophenium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1,2,2-tetrafluoroethanesulfonate, triphenylsulfonium 2- (Bicyclo [2.2.1] hepta-2'-yl) -1,1-di , And the like Le Oro ethanesulfonate.

[1-1] Polymer (A): The polymer (A) is at least one selected from repeating units represented by the following general formula (1-1) or repeating units selected from (1-2) (hereinafter referred to as the following). , Also referred to as “repeating unit (1)”), containing a repeating unit represented by the following general formula (2), and containing a repeating unit represented by the following general formula (3) To do. With such a configuration, since the polymer (A) contains a repeating unit having a hydrocarbon group, there is an advantage that it has a sufficiently high receding contact angle and a sufficiently low advancing contact angle.

（一般式（１−１）及び（１−２）において、Ｒ^１は水素原子、メチル基又はトリフルオロメチル基を示し、Ｒ^２、Ｒ^３は互いに独立に単結合又は炭素数１〜６の直鎖状或いは分岐状のアルカンジイル基、炭素数４〜１２の脂環式のアルカンジイル基を示し、Ｒ^４は少なくとも一つのフッ素を含有する炭素数１〜１０の直鎖状或いは分岐状のアルキル基、炭素数３〜１０の脂環式のアルキル基を示す。）

(In the general formulas (1-1) and (1-2), R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group, and R ² and R ³ are each independently a single bond or a C 1-6 carbon atom. A linear or branched alkanediyl group, an alicyclic alkanediyl group having 4 to 12 carbon atoms, and R ⁴ is a linear or branched chain having 1 to 10 carbon atoms containing at least one fluorine. An alkyl group and an alicyclic alkyl group having 3 to 10 carbon atoms are shown.)

（一般式（２）中、Ｒ^１は水素原子、メチル基又はトリフルオロメチル基を示し、Ｒ^５は少なくとも一つの水素原子がフッ素原子で置換された炭素数１〜１２の直鎖状もしくは分岐状の１価の炭化水素基、または少なくとも一つの水素原子がフッ素原子で置換された炭素数３〜２０の脂環式の１価の炭化水素基を示す。）

(In the general formula (2), R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group, and R ⁵ represents a linear or branched group having 1 to 12 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom. A monovalent hydrocarbon group in the form of a ring, or an alicyclic monovalent hydrocarbon group having 3 to 20 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom.)

（一般式（３）中、Ｒ^１は水素原子、メチル基又はトリフルオロメチル基を示し、Ｒ^６は炭素数１〜１２の直鎖状もしくは分岐状の１価の炭化水素基、または炭素数３〜２０の脂環式の１価の炭化水素基を示す。）

(In the general formula (3), R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group, and R ⁶ represents a linear or branched monovalent hydrocarbon group having 1 to 12 carbon atoms, or the number of carbon atoms. 3 to 20 alicyclic monovalent hydrocarbon groups are shown.)

R ^{2 in the} general formula (1-1) represents a single bond, a linear or branched alkanediyl group having 1 to 6 carbon atoms, or an alicyclic alkanediyl group having 4 to 12 carbon atoms, and is preferably R ^2. As a methylene group, an ethylene group, a propylene group such as a 1,3-propylene group or a 1,2-propylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group, an octamethylene group, a nonamethylene group, Decamethylene group, undecamethylene group, dodecamethylene group, tridecamethylene group, tetradecamethylene group, pentadecamethylene group, hexadecamethylene group, heptadecamethylene group, octadecamethylene group, nonacamethylene group, 1-methyl -1,3-propylene group, 2-methyl-1,3-propylene group, 2-methyl-1,2-propylene group, 1-methyl 1,4-butylene group, 2-methyl-1,4-butylene group, methylidene group, ethylidene group, propylidene group, saturated chain hydrocarbon group such as 2-propylidene group, 1,3-cyclobutylene Cyclobutylene groups such as 1,3-cyclopentylene groups, cyclopentylene groups such as 1,4-cyclohexylene groups, cyclohexylene groups such as 1,4-cyclohexylene groups, cyclooctylene groups such as 1,5-cyclooctylene groups, etc. A monocyclic hydrocarbon ring group such as a cycloalkanediyl group having 3 to 10 carbon atoms, a norbornylene group such as a 1,4-norbornylene group or a 2,5-norbornylene group, a 1,5-adamantylene group, 2,6 -A bridged cyclic hydrocarbon ring group such as a hydrocarbon ring group having 2 to 4 cyclic carbon atoms such as an adamantylene group such as an adamantylene group.

In particular, when R ² contains a divalent alicyclic hydrocarbon group, an alkanediyl group having 1 to 4 carbon atoms is used as a spacer between the bistrifluoromethyl-hydroxy-methyl group and the aliphatic cyclic hydrocarbon group. It is preferable to insert. R ² is preferably a hydrocarbon group containing a 2,5-norbornylene group, a 1,2-ethylene group, or a propylene group.

Among the monomers that give the general formula (1-1), (meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-3-propyl) ester is preferable, (Meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-butyl) ester, (meth) acrylic acid (1,1,1-trifluoro-2-trifluoro) Methyl-2-hydroxy-5-pentyl) ester, (meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-pentyl) ester, (meth) acrylic acid 2- {[5- (1 ′, 1 ′, 1′-trifluoro-2′-trifluoromethyl-2′-hydroxy) propyl] bicyclo [2.2.1] heptyl} ester, (meth) act 3-{[8- (1 ′, 1 ′, 1′-trifluoro-2′-trifluoromethyl-2′-hydroxy) propyl] tetracyclo [6.2.13, 6.02,7] ] Dodecyl} ester.

R ^{3 in the} general formula (1-2) represents a single bond, a linear or branched alkanediyl group having 1 to 6 carbon atoms, or an alicyclic alkanediyl group having 4 to 12 carbon atoms, and is preferably R ^3. As a methylene group, an ethylene group, a propylene group such as a 1,3-propylene group or a 1,2-propylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group, an octamethylene group, a nonamethylene group, Decamethylene group, undecamethylene group, dodecamethylene group, tridecamethylene group, tetradecamethylene group, pentadecamethylene group, hexadecamethylene group, heptadecamethylene group, octadecamethylene group, nonacamethylene group, insalen group, 1-methyl-1,3-propylene group, 2-methyl-1,3-propylene group, 2-methyl-1,2-propylene Saturated chain hydrocarbon groups such as 1-methyl-1,4-butylene group, 2-methyl-1,4-butylene group, methylidene group, ethylidene group, propylidene group, or 2-propylidene group, , 3-cyclobutylene group, cyclobutylene group, 1,3-cyclopentylene group, etc., cyclopentylene group, 1,4-cyclohexylene group, cyclohexylene group, 1,5-cyclooctylene group, etc. Monocyclic hydrocarbon ring groups such as cycloalkanediyl groups having 3 to 10 carbon atoms such as cyclooctylene groups, norbornylene groups such as 1,4-norbornylene groups or 2,5-norbornylene groups, 1,5-adamantylene Group, adamantylene group such as 2,6-adamantylene group and the like.

R ^{4 in the} general formula (1-2) represents a linear or branched alkyl group having 1 to 10 carbon atoms containing at least one fluorine, or an alicyclic alkyl group having 3 to 10 carbon atoms. A trifluoromethyl group and the like are preferable.

Among the monomers giving the general formula (1-2), preferred are (((trifluoromethyl) sulfonyl) amino) ethyl-1-methacrylate, 2-(((trifluoromethyl) sulfonyl) amino) ethyl. Examples include -1-acrylate and a compound represented by the following formula.

R ^{5 in the} general formula (2) represents an alkyl group having a linear, branched or alicyclic structure having 1 to 12 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom, and is preferably R ^5. As a methylene group, an ethylene group, a propylene group such as a 1,3-propylene group or a 1,2-propylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group, an octamethylene group, a nonamethylene group, Decamethylene group, undecamethylene group, dodecamethylene group, tridecamethylene group, tetradecamethylene group, pentadecamethylene group, hexadecamethylene group, heptadecamethylene group, octadecamethylene group, nonacamethylene group, 1-methyl -1,3-propylene group, 2-methyl 1,3-propylene group, 2-methyl-1,2-propylene Saturated chain hydrocarbon groups such as 1-methyl-1,4-butylene group, 2-methyl-1,4-butylene group, methylidene group, ethylidene group, propylidene group, or 2-propylidene group, , 3-cyclobutylene group, cyclobutylene group, 1,3-cyclopentylene group, etc., cyclopentylene group, 1,4-cyclohexylene group, cyclohexylene group, 1,5-cyclooctylene group, etc. Monocyclic hydrocarbon ring groups such as cycloalkanediyl groups having 3 to 10 carbon atoms such as cyclooctylene groups, norbornylene groups such as 1,4-norbornylene groups or 2,5-norbornylene groups, 1,5-adamantylene And a partially fluorinated or perfluoroalkyl group of a linear or branched alkyl group such as a 2,6-adamantylene group.

Preferred monomers that give the general formula (2) include trifluoromethyl (meth) acrylate, 2,2,2-trifluoroethyl (meth) acrylate, perfluoroethyl (meth) acrylate, Perfluoro n-propyl (meth) acrylic acid ester, perfluoro i-propyl (meth) acrylic acid ester, perfluoro n-butyl (meth) acrylic acid ester, perfluoro i-butyl (meth) acrylic acid ester, perfluoro t-butyl (meth) acrylic acid ester, 2- (1,1,1,3,3,3-hexafluoropropyl) (meth) acrylic acid ester, 1- (2,2,3,3,4,4 , 5,5-octafluoropentyl) (meth) acrylic acid ester, perfluorocyclohexylmethyl (meth) acrylic Acid ester, 1- (2,2,3,3,3-pentafluoropropyl) (meth) acrylic acid ester, 1- (3,3,4,4,5,5,6,6,7,7, 8,8,9,9,10,10,10-heptadecafluorodecyl) (meth) acrylic acid ester, 1- (5-trifluoromethyl-3,3,4,4,5,6,6,6 -Octafluorohexyl) (meth) acrylic acid ester and the like.

In General Formula (3), R ⁶ represents an alkyl group having a linear, branched, or alicyclic structure having 1 to 12 carbon atoms. Preferred R ⁶ includes a methyl group, an ethyl group, 1, 3 -Propyl group such as propyl group or 1,2-propyl group, tetramethyl group, pentamethyl group, hexamethyl group, heptamethyl group, octamethyl group, nonamethyl group, decamethyl group, undecamethyl group, dodecamethyl group, tridecamethyl group, tetradecamethyl group , Pentadecamethyl group, hexadecamethyl group, heptadecamethyl group, octadecamethyl group, nonadecamethyl group, 1-methyl-1,3-propyl group, 2-methyl-1,3-propyl group, 2-methyl-1 , 2-propyl group, 1-methyl-1,4-butyl group, 2-methyl-1,4-butyl group, methylidene group, ethylidene group, Cyclopentyl group such as ropyridene group or saturated chain hydrocarbon group such as 2-propylidene group, cyclobutyl group such as 1,3-cyclobutyl group, cyclopentyl group such as 1,3-cyclopentyl group, and cyclohexyl group such as 1,4-cyclohexyl group , Monocyclic hydrocarbon ring groups such as cycloalkyl groups having 3 to 10 carbon atoms such as cyclooctyl groups such as 1,5-cyclooctyl groups, norbornyl groups such as 1,4-norbornyl groups or 2,5-norbornyl groups And straight chain and branched alkyl groups such as 1,5-adamantyl group and 2,6-adamantyl group, cycloalkyl and the like.

Examples of the monomer used to obtain the repeating unit represented by the general formula (3) include methyl methacrylate, ethyl methacrylate, butyl methacrylate, pentyl methacrylate, cyclohexyl methacrylate, adamantyl methacrylate, Dicyclopentyl methacrylate and the like can be preferably used.

The proportion of the repeating unit (1) in the polymer (A) is preferably 1 to 85 mol%, more preferably 30 to 85 mol%, based on all repeating units of the polymer (A). . When the content ratio of the repeating unit (1) is within the above range, the liquid immersion upper layer film formed from the composition of the present invention exhibits a sufficiently high receding contact angle, and various kinds of resist pattern forming methods described later can be used. This is preferable in that there is no risk of defects.

The ratio of the repeating unit (2) is preferably 5 to 60 mol%, more preferably 5 to 50 mol%, based on all repeating units of the polymer (A). When the content ratio of the repeating unit (2) is within the above range, the liquid immersion upper layer film formed from the composition of the present invention exhibits a sufficiently high receding contact angle. This is preferable in that there is no risk of defects.

The ratio of the repeating unit (3) is preferably 10 to 40 mol%, more preferably 10 to 30 mol%, based on all repeating units of the polymer (A). When the content ratio of the repeating unit (3) is within the above range, it is preferable in that the balance between the receding contact angle and the advancing contact angle expressed by the liquid immersion upper layer film formed from the composition of the present invention is good.

[1-2] Polymer (B): The polymer (B) is a repeating unit represented by the general formula (1-1) and a repeating unit represented by the general formula (1-2). At least one type (hereinafter also referred to as “repeating unit (11)”) and a repeating unit represented by the following general formula (4) (hereinafter also referred to as “repeating unit (41)”). To do.

（一般式（４）において、Ｒ^１は、水素原子、メチル基、又はトリフルオロメチル基を示し、Ｒ^１０は、単結合、又は炭素数１〜６の直鎖状若しくは分岐状の２価の炭化水素基を示す。）

(In General Formula (4), R ¹ represents a hydrogen atom, a methyl group, or a trifluoromethyl group, and R ¹⁰ represents a single bond or a linear or branched divalent divalent having 1 to 6 carbon atoms. Indicates a hydrocarbon group.)

R ^{10 in the} general formula (4) represents a single bond, a linear or branched alkanediyl group having 1 to 6 carbon atoms, or —C (O) XR ⁴ —. R ⁴ represents a linear or branched alkanediyl group having 1 to 6 carbon atoms, and X represents —O— or —NH—. Examples of the linear or branched alkanediyl group having 1 to 6 carbon atoms represented by R ⁴ include a propylene group such as methylene group, ethylene group, 1,3-propylene group or 1,2-propylene group, tetra Examples include a methylene group, a pentamethylene group, and a hexamethylene group. Preferred monomers that give the repeating unit represented by the general formula (4) include vinyl sulfonic acid, allyl sulfonic acid, 2- (meth) acrylamide-2-methyl-1-propanesulfonic acid, 4-vinyl-1 -Benzenesulfonic acid.

The proportion of the repeating unit (11) in the polymer (B) is preferably from 80 to 99 mol%, more preferably from 85 to 99 mol%, based on all repeating units in the polymer (B). . When the ratio of the repeating unit (11) is within the above range, there is no risk of various defects occurring in the resist pattern forming method described later, and there is little influence on the resist layer serving as a base, thereby reducing resist performance. It is preferable in that there is no fear.

The ratio of the repeating unit (41) in the polymer (B) is preferably 1 to 20 mol%, more preferably 1 to 15 mol%, based on all the repeating units of the polymer (B). . When the ratio of the repeating unit (11) is within the above range, there is no risk of various defects occurring in the resist pattern forming method described later, and there is little influence on the resist layer serving as a base, thereby reducing resist performance. It is preferable in that there is no fear.

[1-3] Polymer (C): The polymer (C) is a repeating unit represented by the following general formula (5-1), a repeating unit represented by the following general formula (5-2), and At least one of repeating units represented by the following general formula (5-3) (hereinafter also referred to as “repeating unit (5)”) and a repeating unit represented by the above general formula (4) (hereinafter referred to as “repeating unit (5)”). , Also referred to as “repeating unit (42)”. Examples of the repeating unit represented by the general formula (4) are the same as those already described above.

（一般式（５−１）〜（５−３）において、Ｒ^１はそれぞれ独立に水素原子、メチル基またはトリフルオロメチル基を示し、Ｒ^１２及びＲ^１３はそれぞれ独立に炭素数１〜６の直鎖状若しくは分岐状の２価の炭化水素基、又は炭素数４〜１２の２価の脂環式炭化水素基を示す。）

(In the general formulas (5-1) to (5-3), each R ¹ independently represents a hydrogen atom, a methyl group or a trifluoromethyl group, and each of R ¹² and R ¹³ independently represents one having 1 to 6 carbon atoms. A linear or branched divalent hydrocarbon group or a divalent alicyclic hydrocarbon group having 4 to 12 carbon atoms is shown.)

Examples of the linear or branched divalent hydrocarbon group having 1 to 6 carbon atoms of R ¹² and R ^{13 in} the general formulas (5-1) and (5-2) include an ethylene group; Propylene groups such as 1,3-propylene group and 1,2-propylene group; tetramethylene group, pentamethylene group, hexamethylene group, 1-methyl-1,3-propylene group, 2-methyl-1,3-propylene group 2-methyl-1,2-propylene group, 1-methyl-1,4-butylene group, 2-methyl-1,4-butylene group, ethylidene group, propylidene group, 2-propylidene group, and the like. .

The divalent alicyclic hydrocarbon group having 4 to 12 carbon atoms of the R ¹² and R ^13, for example, a monocyclic hydrocarbon ring group, such as a crosslinked cyclic hydrocarbon ring group. Examples of the monocyclic hydrocarbon ring group include an arylene group such as a phenylene group and a tolylene group, a cyclobutylene group such as a 1,3-cyclobutylene group, and a cyclopentylene group such as a 1,3-cyclopentylene group. And a cycloalkanediyl group having 4 to 12 carbon atoms such as a cyclohexylene group such as 1,4-cyclohexylene group and a cyclooctylene group such as 1,5-cyclooctylene group. Examples of the bridged cyclic hydrocarbon ring group include, for example, norbornylene groups such as 1,4-norbornylene group and 2,5-norbornylene group, adamants such as 1,5-adamantylene group and 2,6-adamantylene group. Examples include 2 to 4 cyclic hydrocarbon ring groups having 4 to 12 carbon atoms such as a tylene group.

Examples of the monomer for obtaining the repeating unit (5-1) include 2-methacryloyloxyethyl hexahydrophthalate, 3-methacryloyloxypropyl hexahydrophthalate, 4-methacryloyloxybutyl hexahydrophthalate, and the like. Is mentioned. Examples of the monomer for obtaining the repeating unit (5-2) include cyclohexacarboxylic acid 2-methacryloyloxy, propylcarboxylic acid 3-methacryloyloxy, and the like. Furthermore, as a monomer for obtaining the said repeating unit (5-3), (meth) acrylic acid is mentioned, for example.

The polymer (C) further contains a repeating unit (42). By containing the repeating unit (42) in the polymer (C), the problem that the resin, which is the main component of the photoresist film, is redeposited on the photoresist film in the rinse cleaning process after development (blob defect) is suppressed. can do. At the time of development at the unexposed photoresist film / upper layer film interface, the upper layer film component diffuses while dissolving in the developer, while the photoresist film component diffuses without dissolving in the developer. Therefore, it is considered that the main cause of the Blob defect is that the resin component that has not been dissolved in the developer re-deposits on the photoresist film. When the polymer (C) contains a repeating unit (42) having a strongly acidic group, among the resin components in the photoresist film, those present in the vicinity of the interface can be improved in solubility in the developer, It is thought that the reattachment of the resin after the rinse cleaning can be suppressed.

The ratio of the repeating unit (5) in the polymer (C) is preferably 80 to 99 mol%, more preferably 85 to 99 mol%, based on all repeating units of the polymer (C). . When the ratio of the repeating unit (5) is within the above range, there is no possibility of causing various defects in the resist pattern forming method described later, and the influence on the resist layer as a base is small, resulting in a decrease in resist performance. It is preferable in that there is no.

The proportion of the repeating unit (42) in the polymer (C) is preferably 1 to 20 mol%, more preferably 1 to 15 mol%, based on all repeating units of the polymer (C). . When the ratio of the repeating unit (42) is within the above range, there is no possibility of causing various defects in the resist pattern forming method described later, and the influence on the resist layer as a base is small, resulting in a decrease in resist performance. It is preferable in that there is no.

Moreover, since the polymer (A) has higher water repellency than the polymer (B) (and the polymer (C)), the polymer (A) and the polymer (B) (and the polymer (C) )) Is blended, the polymer (A) can be unevenly distributed on the polymer (B), and the function can be shared by the uneven distribution. That is, the highly water-repellent polymer (A) that is unevenly distributed on the upper part of the upper layer film does not decrease the receding contact angle with blending with the polymer (B) and can prevent watermark defects due to the remaining droplets. Further, the polymer (B) (and the polymer (C)) has excellent alkali developer solubility, and the polymer (B) (and the polymer (C)) is a lower part of the polymer (A). By being unevenly distributed (at the interface between the resist film and the liquid immersion upper layer film), it is possible to suppress a decrease in solubility of the intermixing layer and reduce Blob defects. Therefore, a blob defect can be prevented in addition to a conventional watermark defect.

The polymer (A), polymer (B) and polymer (C) (hereinafter collectively referred to as “polymer component”) of the upper layer film-forming composition of the present invention include molecular weight, glass For the purpose of controlling the transition point, solubility in a solvent, etc., repeating units derived from other radical polymerizable monomers (hereinafter sometimes referred to as “other repeating units”), acid-dissociable group-containing units A structural unit derived from a monomer can be contained.

Examples of the monomer used to obtain the other repeating unit include dicarboxylic acid diesters such as diethyl maleate, diethyl fumarate and diethyl itaconate; phenyl (meth) acrylate, benzyl (meth) acrylate and the like ( (Meth) acrylic acid aryl ester; styrene, α-methylstyrene, m-methylstyrene, p-methylstyrene, vinyltoluene, p-methoxystyrene and other aromatic vinyl, nitrile group-containing radical polymerization such as acrylonitrile, methacrylonitrile Amide bond-containing radical polymerizable monomers such as acrylamide and methacrylamide; Fatty acid vinyls such as vinyl acetate; Chlorine-containing radical polymerizable monomers such as vinyl chloride and vinylidene chloride; 1,3-butadiene , Isoprene, 1,4-di Conjugated diolefins such as chill-butadiene. Of these, (meth) acrylic acid alkyl esters, nitrile group-containing radical polymerizable monomers, amide bond-containing radical polymerizable monomers, and hydroxyl group-containing (meth) acrylic acid alkyl esters are preferred. In addition, these monomers can be used individually or in combination of 2 or more types.

The ratio of the other repeating unit may be 50 mol% or less with respect to all the repeating units of the polymer (A), the polymer (B) or the polymer (C) containing the other repeating unit. Preferably, it is 40 mol% or less. When the ratio is more than 50 mol%, the solubility in an alkaline aqueous solution as a developer is lowered, so that it is difficult to remove the upper layer film, and a residue may be generated on the resist pattern after development.

The production method of the polymer component is not particularly limited. For example, the polymer component radically polymerizes one or more corresponding radical polymerizable monomers in a polymerization solvent in the presence of an appropriate initiator or chain transfer agent. Can be manufactured.

Examples of the polymerization solvent used in producing the polymer component include alcohols, cyclic ethers, alkyl ethers of polyhydric alcohols, alkyl ether acetates of polyhydric alcohols, aromatic hydrocarbons, and ketones. And esters. Of these, cyclic ethers, alkyl ethers of polyhydric alcohols, alkyl ether acetates of polyhydric alcohols, ketones, and esters are preferable.

The weight average molecular weight (hereinafter may be referred to as “Mw”) of the polymer component is preferably 2,000 to 100,000, more preferably 2,500 to 50,000, respectively. 3,000 to 20,000 is particularly preferable. When the Mw of the polymer component is within the above range, it is preferable from the viewpoint of water resistance and mechanical properties as an upper layer film and solubility in the solvent. Further, the ratio (Mw / Mn) of Mw and number average molecular weight (hereinafter sometimes referred to as “Mn”) of the polymer component is preferably 1 to 5, and preferably 1 to 3. Further preferred. In the present specification, “weight average molecular weight” and “number average molecular weight” are values in terms of polystyrene measured by gel permeation chromatography (GPC).

The composition for forming the upper layer film of the present invention is preferably as less as possible as impurities such as halogen ions and metals. By reducing the impurities, the coating property as the upper layer film and the uniform solubility in the alkali developer are obtained. Further improvements can be made. Examples of the purification method of the polymer component for obtaining such a composition include chemical purification methods such as washing with water and liquid-liquid extraction, and these chemical purification methods and physical filtration such as ultrafiltration and centrifugation. The combination with a purification method etc. can be mentioned.

In addition, the polymer component can form a stable upper film (protective film) against a medium such as water (immersion liquid) upon irradiation with radiation, and can also be used as a developer for forming a resist pattern. It is a resin that can be dissolved. Here, “stable against immersion liquid” means that the rate of change in film thickness measured as a result of the following “stability evaluation test” is within 3% of the initial film thickness. And

[Stability evaluation test]: (1): Coater / developer (1) (trade name: CLEAN TRACK ACT8, manufactured by Tokyo Electron Ltd.) was used to spin coat the upper layer film-forming composition on an 8-inch silicon wafer, By performing pre-baking (PB) at 90 ° C. for 60 seconds, an upper layer film having a thickness of 90 nm is formed. The film thickness (initial film thickness) of this upper layer film is measured using an optical interference type film thickness measuring device (trade name: Lambda Ace VM-2010, manufactured by Dainippon Screen Mfg. Co., Ltd.).

(2): Next, after the ultrapure water was discharged from the rinse nozzle of the coater / developer (1) for 60 seconds onto the surface of the wafer on which the upper layer film was formed, it was shaken off at a rotational speed of 4000 rpm for 15 seconds, and spin-dried To do. At this time, the film thickness of the upper film is measured again, and the film thickness change (reduced film thickness) of the upper film is calculated. If the ratio of the reduced film thickness to the initial film thickness is within 3%, it is evaluated as “stable against immersion liquid”.

Further, “dissolving in a developer after formation of a resist pattern” means that there is no residue on the resist pattern after development using an alkaline aqueous solution and the upper layer film is removed. That is, the polymer component contained in the upper layer film-forming composition of the present invention hardly dissolves in a medium such as water, and dissolves in the alkaline aqueous solution during development using the alkaline aqueous solution after irradiation. It is an alkali-soluble resin.

The upper layer film formed by the upper layer film-forming composition containing such a polymer component prevents the photoresist film and a medium such as water from coming into direct contact during immersion exposure, and the photoresist due to the penetration of the medium. There is an effect of preventing contamination of the lens of the projection exposure apparatus due to components eluted from the photoresist film without deteriorating the lithography performance of the film.

The content ratio of the polymer (A) is preferably 20% by mass or more, more preferably 25% by mass or more and less than 60% by mass, when the total of the polymer components is 100% by mass. It is particularly preferably 30% by mass or more and 50% by mass or less. The content is preferably 20% by mass or more, but if the content is 60% by mass or more, BLOB defects may occur.

[1-3] Solvent (S): It is preferable to add a solvent (S) to the upper layer film-forming composition of the present invention for the purpose of dissolving the polymer component. As the solvent, a solvent that hardly deteriorates the lithography performance, such as generating intermixing with the photoresist film when applied onto the photoresist film, can be suitably used.

Examples of the solvent (S) include monohydric alcohols, polyhydric alcohols, polyhydric alcohol alkyl ethers, polyhydric alcohol alkyl ether acetates, ethers, cyclic ethers, higher hydrocarbons, aromatics. Group hydrocarbons, ketones, esters, water and the like.

Examples of the monohydric alcohols include 1-butyl alcohol, 2-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, tert-amyl alcohol, and neopentyl. Alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, 2,3-dimethyl-2 -Butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-diethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2 -Methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2- Monovalent compounds having 4 to 10 carbon atoms such as butanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, etc. An alcohol can be preferably mentioned.

Examples of the polyhydric alcohols include ethylene glycol and propylene glycol; and examples of polyhydric alcohol alkyl ethers include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and diethylene glycol monomethyl ether. , Diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, etc .; Call ethyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol monomethyl ether acetate.

Examples of the ethers include dipropyl ether, diisopropyl ether, butyl methyl ether, butyl ethyl ether, butyl propyl ether, dibutyl ether, diisobutyl ether, tert-butyl methyl ether, tert-butyl ethyl ether, tert-butyl propyl. Ether, di-tert-butyl ether, dipentyl ether, diisoamyl ether, cyclopentyl methyl ether, cyclohexyl methyl ether, cyclopentyl ethyl ether, cyclohexyl ethyl ether, cyclopentyl propyl ether, cyclopentyl-2-propyl ether, cyclohexyl propyl ether, cyclohexyl-2- Propyl ether, cyclopentyl butyl ether, cyclopentyl-te t- butyl ether, cyclohexyl ether, and cyclohexyl -tert- butyl ether. Examples of cyclic ethers include tetrahydrofuran and dioxane.

Examples of the higher hydrocarbons include decane, dodecane, and undecane. Examples of aromatic hydrocarbons include benzene, toluene, xylene and the like. Examples of ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, 4-hydroxy-4-methyl-2-pentanone, diacetone alcohol, and the like. Esters include ethyl acetate, butyl acetate, ethyl 2-hydroxypropionate, methyl 2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, 2- Mention may be made of methyl hydroxy-3-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate and methyl 3-ethoxypropionate.

Of these, monohydric alcohols, ethers, cyclic ethers, polyhydric alcohol alkyl ethers, polyhydric alcohol alkyl ether acetates, and higher hydrocarbons are preferred. Particularly preferably, it contains an alcohol having 4 to 10 carbon atoms and / or an alkyl ether having an alkyl chain having 4 to 10 carbon atoms.

Moreover, the composition for forming the upper layer film can be prepared by filtering a solution adjusted so that the total solid content concentration thereof becomes a desired value with a filter having a pore diameter of about 200 nm. In addition, although the said solid content concentration is not specifically limited and can be suitably adjusted, the solid content concentration at the time of coating the composition for upper layer film formation is 0.1-20.0 mass% normally. In the present specification, “solid content” refers to a component obtained by removing the solvent from the composition for forming an upper layer film.

[1-4] Additive: The upper layer film-forming composition of the present invention may contain a surfactant or the like for the purpose of improving coating properties, antifoaming properties, leveling properties and the like.

Examples of the surfactant include BM-1000 and BM-1100 (all manufactured by BM Chemie), MegaFuck F142D, F172, F173, and F183 (all Dainippon Ink and Chemicals, Inc.) ), FLORARD FC-135, FC-170C, FC-430, FC-431 (above, manufactured by Sumitomo 3M), Surflon S-112, S-113, S-131, S- 141, S-145 (above, manufactured by Asahi Glass), SH-28PA, -190, -193, SZ-6032, SF-8428 (above, manufactured by Toray Dow Corning Silicone), Emulgen A-60, 104P , 306P (manufactured by Kao Co., Ltd.) and other commercially available fluorosurfactants can be used. The blending amount of these surfactants is preferably 5% by mass or less with respect to 100% by mass of the total amount of the polymer components.

The upper layer film-forming composition of the present invention contains the above polymer component, and after the upper layer film-forming composition is coated on the surface of the photoresist film, pre-baking is performed at 50 to 150 ° C. for 1 to 360 seconds. When the upper layer film is formed by performing the above process, an upper layer film having a receding contact angle of 75 ° or more and an advancing contact angle of 95 ° or less with respect to water of the upper layer film can be obtained (herein referred to as “upper layer film” "The receding contact angle with water / advanced contact angle when forming the film" means that a 4-methyl-2-pentanol solution of a polymer is spin-coated on an 8-inch silicon wafer, and heated at 90 ° C, 60 ° C on a hot plate. Second PB is performed to form a coating film (upper layer film) with a film thickness of 30 nm, and thereafter, using the product name “DSA-10” (manufactured by KRUS), quickly, room temperature: 23 ° C., humidity: 45% Refers to the value measured under normal pressure environment. Antenna: measured by sucking a 25 μL water droplet placed on the upper film at a speed of 10 μL / min, and advancing contact angle: a 15 μL water drop placed on the upper film at a speed of 10 μL / min Measured by discharging with a). By having a sufficiently high receding contact angle and a sufficiently low advancing contact angle in this way, even when forming a resist pattern at a high scan speed, it is difficult for droplets to remain on the photoresist film. It is possible to effectively suppress the occurrence of defects such as bubble defects due to the difficulty of generating bubbles at the interface between the immersion liquid and the upper layer film.

[2] Photoresist pattern forming method: Next, an embodiment of the photoresist pattern forming method of the present invention will be described. The method for forming a photoresist pattern of the present invention comprises a step of applying a photoresist composition on a substrate to form a photoresist film (step (1)), and the above-described upper layer film-forming composition is applied to the photoresist film. A step of applying and forming an upper layer film (step (2)), an immersion medium is disposed between the upper layer film and the lens, and the photo is passed through the immersion medium and a mask having a predetermined pattern. Irradiating the resist film and the upper layer film with exposure light and then developing the resist pattern to obtain a resist pattern (step (3)).

By providing such a process, the photoresist pattern forming method of the present invention has sufficient transmission with respect to the exposure wavelength, particularly 248 nm (KrF) and 193 nm (ArF), and causes almost intermixing with the photoresist film. It is formed on the photoresist film without immersion and maintains a stable coating that is extremely difficult to elute in a medium such as water during immersion exposure, and can form a high-resolution resist pattern while having a sufficiently high receding contact angle. The upper layer film, that is, the occurrence of watermark defects and pattern defect defects can be effectively suppressed at a normal scan speed (for example, 500 mm / s), and even if the scan speed is high (for example, 700 mm / s) The occurrence of defects can be effectively suppressed.

(Step (1)) Step (1) is a step of forming a photoresist film by applying a photoresist composition onto a substrate. As the substrate, a silicon wafer, a silicon wafer coated with aluminum, or the like is usually used. In order to maximize the characteristics of the photoresist film, an organic or inorganic antireflection film is preferably formed on the surface of the substrate in advance (for example, Japanese Patent Publication No. 6-12252). (See the official gazette).

The type of the material for forming the photoresist film is not particularly limited, and it is appropriately selected from materials conventionally used for forming a photoresist film according to the purpose of use of the resist. do it. However, it is preferable to use a chemically amplified resist material containing an acid generator, particularly a positive resist material. Examples of the chemically amplified positive resist material include a radiation sensitive resin composition containing an acid dissociable group-modified alkali-soluble resin and a radiation sensitive acid generator as essential components. In such a resin composition, an acid is generated from an acid generator by irradiation (exposure), and an acid-dissociable group that protected an acidic group (for example, a carboxyl group) of the resin by the action of the generated acid. Dissociates to expose acidic groups. When the acidic group is exposed, the alkali solubility of the exposed portion of the resist is increased, and the exposed portion is dissolved and removed by the alkali developer, so that a positive resist pattern can be formed.

As said resin, the thing similar to the polymer (X) already mentioned above can be used conveniently.

As said acid generator, the thing similar to the acid generator (Y) already mentioned above can be used conveniently.

For the photoresist film, a solvent is added to the resin component for forming the photoresist film to obtain a solution in which the total solid content concentration is adjusted to 0.2 to 20% by mass, and the resulting solution is obtained with a pore diameter of about 30 nm. A coating liquid is prepared by filtering with a filter, and the coating liquid can be formed by coating on a substrate using a conventionally known coating method such as spin coating, cast coating, roll coating, or the like. it can. This photoresist film may be pre-baked (hereinafter may be referred to as “PB”) in order to volatilize the solvent. In forming the photoresist film, the coating solution may be prepared by itself or a commercially available resist solution may be used as the coating solution.

(Step (2)) Step (2) is a step of forming the upper layer film by applying the above-described upper layer film forming composition to the photoresist film. This step is a step of forming the upper layer film by applying the above-described upper layer film forming composition on the surface of the photoresist film formed in the step (1) and preferably baking again. By forming the upper layer film, the immersion liquid is prevented from coming into direct contact with the photoresist film during the immersion exposure, and the lithography performance of the photoresist film is reduced by the penetration of the immersion liquid, or the photoresist film It is possible to effectively prevent the lens of the projection exposure apparatus from being contaminated by the components eluted from

The thickness of the upper layer film is preferably as close as possible to an odd multiple of λ / 4m (where λ is the wavelength of radiation and m is the refractive index of the protective film). This is because the reflection suppressing effect at the upper interface of the photoresist film is increased.

(Step (3)) In the step (3), an immersion medium is disposed between the upper layer film and the lens, and the photoresist film and the upper layer are interposed through the immersion medium and a mask having a predetermined pattern. In this step, a resist pattern is obtained by irradiating the film with exposure light and then developing the film.

As the immersion medium, a liquid having a higher refractive index than air is usually used. Specifically, water is preferably used, and pure water is more preferably used. In addition, you may adjust pH of immersion liquid as needed. With this immersion medium interposed (that is, with the immersion medium filled between the lens of the exposure apparatus and the photoresist film), the photoresist film is irradiated with radiation through a mask having a predetermined pattern. To expose.

The radiation that can be used in the immersion exposure may be appropriately selected according to the type of the photoresist film and the upper layer film used, and examples thereof include visible light; ultraviolet light such as g-line and i-line; excimer laser. Various radiations such as deep ultraviolet rays such as X-rays, X-rays such as synchrotron radiation, and charged particle beams such as electron beams can be used. Among these, it is preferable to use an ArF excimer laser (wavelength 193 nm) or a KrF excimer laser (wavelength 248 nm). Moreover, what is necessary is just to set suitably exposure conditions, such as a radiation dose, according to the compounding composition of a radiation sensitive resin composition, the kind of additive, etc.

In order to improve the resolution, pattern shape, developability, and the like of the photoresist film, baking (PEB) is preferably performed after exposure. The firing temperature is appropriately adjusted depending on the type of the radiation-sensitive resin composition used, and is usually 30 to 200 ° C, preferably 50 to 150 ° C.

A desired photoresist pattern can be formed by performing development after exposure or PEB and washing as necessary. The upper layer film is formed by the upper layer film forming composition which is one embodiment of the present invention. Therefore, this upper layer film does not need to be removed by a separate peeling step, and can be easily removed during development or washing after development. In developing, an alkaline developer is usually used.

Examples of the developer include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, dimethylethanol. Amine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1,5-diazabicyclo- [4. 3.0] It is preferable to use an alkaline aqueous solution in which at least one alkaline compound such as 5-nonane is dissolved. Especially, the aqueous solution of tetraalkylammonium hydroxide can be used suitably.

For example, an appropriate amount of a water-soluble organic solvent including alcohols such as methanol and ethanol, and a surfactant can be added to the developer. In addition, when developing using said alkaline aqueous solution, it wash | cleans with water after image development normally. In addition, if it dries suitably after image development or the water washing as needed, the target photoresist pattern can be formed.

EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples. In the examples and comparative examples, “parts” and “%” are based on mass unless otherwise specified. Moreover, the measuring method of various physical-property values and the evaluation method of various characteristics are shown below.

As the above-mentioned polymer (A), polymer (B) and polymer (C), a polymer (A-1) which can form a stable film in water upon irradiation with radiation and dissolves in a developer after forming a resist pattern ) And (B-1) and (C-1) were synthesized by the method shown below. In addition, for comparison with the polymer (A-1), a polymer (A ′) was also synthesized.

[Molecular weight (Mw, Mn) measurement method]: Mw and Mn of the polymers (A-1), (A '), (A-2), (B-1) and (C-1) are manufactured by Tosoh Corporation. Using a GPC column (trade name “G2000H _XL ”; two, “G3000H _XL ”; one, “G4000H _XL ”; one) manufactured by Tosoh Corporation) in a high-speed GPC apparatus (model “HLC-8120”) Measurement was performed by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard under the analysis conditions of 1.0 ml / min, elution solvent tetrahydrofuran, and column temperature of 40 ° C.

Synthesis Example 1 A monomer solution was prepared by dissolving 1.06 g of initiator (methyl 2,2′-azobis- (2-methylpropionate)) in 1.06 g of methyl ethyl ketone. Methacrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-pentyl) ester as a monomer used to obtain the repeating unit represented by the general formula (1-1) 8.16 g and 7.77 g of methacrylic acid (2,2,2-trifluoroethyl) ester as a monomer used to obtain the repeating unit represented by the general formula (2), and the general formula (3) ) 4.07 g of a dicyclopentyl methacrylate (compound represented by the following formula (M-3)) and 18.94 g of methyl ethyl ketone as a monomer used to obtain a repeating unit represented by It was put into a 100 ml three-necked flask equipped with a funnel and purged with nitrogen for 30 minutes. After purging with nitrogen, the inside of the flask was heated to 80 ° C. while stirring with a magnetic stirrer. Using a dropping funnel, a prepared initiator solution was added dropwise over 5 minutes. After completion of dropping, the reaction was further continued for 6 hours. It cooled to 30 degrees C or less, and the copolymer liquid was obtained.

The obtained copolymer solution was concentrated to 30 g and transferred to a separatory funnel. To this separatory funnel, 30 g of methanol and 150 g of n-hexane were added to carry out separation and purification. After separation, 50.3 g of the lower layer solution was recovered. The recovered upper layer liquid was replaced with 4-methyl-2-pentanol to obtain a resin solution. The solid content concentration of the sample (resin solution) after substitution with 4-methyl-2-pentanol was measured by weighing 0.3 g of the resin solution in an aluminum dish and heating on a hot plate at 140 ° C. for 1 hour. Then, the mass was calculated from the mass of the resin solution before heating and the mass of the residue (after heating). This solid content concentration was used for the preparation of the upper layer film-forming composition solution and the yield calculation. The copolymer contained in the obtained resin solution had Mw of 9,760, Mw / Mn of 1.5, and the yield was 80%. Derived from tacrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-pentyl) ester, methacrylic acid (2,2,2-trifluoroethyl) ester, dicyclopentyl methacrylate The content of each repeating unit was a copolymer (lipid-soluble resin) having a ratio of 30:50:20 (mol%). This copolymer is referred to as “polymer (A-1)”.

Synthesis Example 2 Methacrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2) is used as a monomer used to obtain the repeating unit represented by the general formula (1-1). A monomer solution (1) in which 37.3 g of -hydroxy-4-pentyl) ester was previously dissolved in 4.5 g of methyl ethyl ketone was prepared. On the other hand, methacrylic acid (1,1,1,3,3) is used as a monomer to obtain a repeating unit represented by the above general formula (2) in a 500 ml three-necked flask equipped with a thermometer and a dropping funnel. , 3-hexafluoro-2-propyl) ester, 69.6 g of 2,2-azobis (methyl 2-methylisopropionate) and 95.5 g of methyl ethyl ketone were added and purged with nitrogen for 30 minutes. After purging with nitrogen, the flask was heated to 75 ° C. while stirring with a magnetic stirrer. Using a dropping funnel, the monomer solution (1) prepared in advance was dropped over 5 minutes and aged for 6 hours, and then cooled to 30 ° C. or lower to obtain a copolymer solution.

The obtained copolymer solution was concentrated to 150 g and transferred to a separatory funnel, and 150 g of methanol and 750 g of n-hexane were added to the separatory funnel for separation and purification, and the lower layer solution was recovered. The solvent of the recovered lower layer solution was replaced with 4-methyl-2-pentanol. The solid content concentration of the sample after substitution with 4-methyl-2-pentanol was obtained by placing 0.3 g of the sample (resin solution) on an aluminum dish and heating it on a hot plate heated to 140 ° C. for 1 hour. Calculated from the mass of the residue. The calculated solid content concentration was used for the subsequent resin preparation and yield calculation. Mw of the copolymer contained in the obtained resin solution was 7500, Mw / Mn was 1.50, and the yield was 50%. Methacrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-pentyl) ester, methacrylic acid (1,1,1,3,3,3-hexafluoro-2-propyl) The content of each repeating unit derived from the ester was a copolymer (a fat-soluble resin) having a ratio of 60:40 (mol%). This copolymer is referred to as “polymer (A ′)”.

Using the same method as in Synthesis Example 1, a polymer (A-2) was synthesized with the composition shown in Table 1.

(Synthesis Example 3) Monomer methacrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-) used for obtaining the repeating unit represented by the general formula (1-1) described above Monomer solution in which 46.95 g (85 mol%) of hydroxy-4-pentyl) ester and 6.91 g of initiator (methyl 2,2′-azobis- (methyl 2-methylpropionate)) were dissolved in 100 g of isopropanol Prepared. Meanwhile, 50 g of isopropanol was charged into a 500 ml three-necked flask equipped with a thermometer and a dropping funnel, and purged with nitrogen for 30 minutes. After purging with nitrogen, the inside of the flask was heated to 80 ° C. while stirring with a magnetic stirrer, and a monomer solution prepared in advance was added dropwise over 2 hours using a dropping funnel. After completion of the dropwise addition, the reaction was continued for another hour, and 30 g of an isopropanol solution of 3.05 g (15 mol%) of the monomer vinyl sulfonic acid used to obtain the repeating unit represented by the general formula (4) was added. The reaction was continued dropwise over a period of 1 hour. The copolymer liquid was obtained by cooling until it became 30 degrees C or less.

The copolymer solution was concentrated to 150 g, and 50 g of methanol and 600 g of n-hexane were put into the separatory funnel and subjected to separation and purification. After separation, the lower layer was recovered. The lower layer solution was diluted with isopropanol to make 100 g, transferred again to a separatory funnel, 50 g of methanol and 600 g of n-hexane were put into the separatory funnel, separation and purification were performed again, and the lower layer was recovered after separation. The recovered lower layer liquid was replaced with 4-methyl-2-pentanol, the total amount was adjusted to 250 g, liquid separation with 250 g of water was performed, the upper layer was recovered, and replaced with 4-methyl-2-pentanol again. . The solid content concentration of the sample after solvent replacement was calculated from the mass of the residue after 1 hour of heating on a hot plate heated to 140 ° C. by placing 0.3 g of the resin solution on an aluminum dish, and then forming a protective film The composition solution was used for the preparation and yield calculation. Mw, Mw / Mn (dispersion of molecular weight), and yield (% by mass) of the obtained copolymer were 9,760, 1.51, and 65%, respectively, and methacrylic acid (1,1,1 -Trifluoro-2-trifluoromethyl-2-hydroxy-4-pentyl) ester, a copolymer (lipid-soluble resin) in which the content of each repeating unit derived from vinylsulfonic acid is 95: 5 (mol%). there were. This polymer is referred to as “polymer (B-1)”.

(Synthesis example 4) The monomer [hexahydrophthalic acid 2-methacryloyloxyethyl] 46.95g (85 mol%) used in order to obtain the repeating unit represented by the above-mentioned general formula (5-1), and A monomer solution in which 6.91 g of initiator [methyl 2,2′-azobis- (2-methylpropionate)] was dissolved in 100 g of isopropanol was prepared. Meanwhile, 50 g of isopropanol was charged into a 500 ml three-necked flask equipped with a thermometer and a dropping funnel, and purged with nitrogen for 30 minutes. After purging with nitrogen, the inside of the flask was heated to 80 ° C. while stirring with a magnetic stirrer. And the monomer solution prepared beforehand was dripped over 2 hours using the dropping funnel. After completion of the dropwise addition, the reaction is further continued for 1 hour, and 10 g of an isopropanol solution of 3.05 g (15 mol%) of a monomer [vinyl sulfonic acid] used to obtain the repeating unit represented by the general formula (4) described above. Was added dropwise over 30 minutes. Thereafter, the reaction was further performed for 1 hour, and then cooled to 30 ° C. or lower to obtain a copolymer solution.

The obtained copolymer solution was concentrated to 150 g and then transferred to a separatory funnel. The separatory funnel was charged with 50 g of methanol and 600 g of n-hexane to carry out separation and purification. After separation, the lower layer solution was recovered. This lower layer solution was diluted with isopropanol to 100 g, and again transferred to a separatory funnel. Thereafter, 50 g of methanol and 600 g of n-hexane were added to the separatory funnel, separation and purification were performed, and the lower layer liquid was recovered after separation. The recovered lower layer solution was replaced with 4-methyl-2-pentanol, and the total amount was adjusted to 250 g. After the adjustment, 250 g of water was added for separation and purification. After separation, the upper layer liquid was recovered. The recovered upper layer liquid was replaced with 4-methyl-2-pentanol to obtain a resin solution. The solid content concentration of the sample after solvent replacement was calculated from the mass of the residue after 1 hour of heating on a hot plate heated to 140 ° C. by placing 0.3 g of the resin solution on an aluminum dish, and then forming a protective film The composition solution was used for the preparation and yield calculation. Mw of the copolymer contained in the obtained resin solution was 11060, Mw / Mn was 1.55, and the yield was 75%. Moreover, the content rate of the repeating unit derived from 2-methacryloyloxyethyl hexahydrophthalate contained in this copolymer and the repeating unit derived from vinylsulfonic acid was 95: 5 (mol%). . This copolymer is referred to as “polymer (C-1)”.

Preparation of Radiation Sensitive Resin Composition (D) A radiation sensitive resin composition for forming a photoresist film was prepared by the following method. Synthesis example of polymers (D-1) and (D-2) for radiation-sensitive resin composition

Synthesis Example 5 53.93 g (50 mol%) of the following compound (M-1), 35.38 g (40 mol%) of the compound (M-2), 10.69 g (10 mol%) of the compound (M-5) Was dissolved in 200 g of 2-butanone, and then a monomer solution containing 5.58 g of dimethyl 2,2′-azobis (2-methylpropionate) was prepared, and 500 ml of three-necked solution containing 100 g of 2-butanone was prepared. The flask was purged with nitrogen for 30 minutes. After purging with nitrogen, the reaction kettle was heated to 80 ° C. with stirring, and the monomer solution prepared in advance was added dropwise using a dropping funnel over 3 hours. The polymerization start was carried out for 6 hours with the start of dropping as the polymerization start time. After completion of the polymerization, the polymerization solution was cooled with water to 30 ° C. or lower, poured into 2000 g of methanol, and the precipitated white powder was separated by filtration. The filtered white powder was washed twice with 400 g of methanol on the slurry, filtered, and dried at 50 ° C. for 17 hours to obtain a white powder polymer (74 g, yield 74%). . As for this polymer, Mw is 6900, Mw / Mn = 1.70, and as a result of 13C-NMR analysis, each repeating unit derived from the compound (M-1), the compound (M-2), and the compound (M-3). The content ratio was 53.0: 37.2: 9.8 (mol%). This polymer is referred to as “acrylic polymer (A-1)”. In addition, content of the low molecular weight component derived from each monomer in this polymer was 0.03 mass% with respect to 100 mass% of this polymer. This is referred to as a polymer (D-1).

(Synthesis Example 6) 47.54 g (46 mol%) of the above compound (M-1), 12.53 g (15 mol%) of the compound (M-2), 39.93 g (39 mol%) of the compound (M-3) Was dissolved in 200 g of 2-butanone, and a monomer solution into which 4.08 g of 2,2′-azobis (isobutyronitrile) was further added was prepared. On the other hand, a 1000 ml three-necked flask charged with 100 g of 2-butanone was prepared and purged with nitrogen for 30 minutes. After the nitrogen purge, the contents in the three-necked flask were heated to 80 ° C. while stirring, and the monomer solution prepared in advance was added dropwise over 3 hours using a dropping funnel. The polymerization start was carried out for 6 hours with the start of dropping as the polymerization start time. After completion of the polymerization, the polymerization solution was cooled with water to 30 ° C. or lower, poured into 2000 g of methanol, and the precipitated white powder was separated by filtration. The filtered white powder was washed twice with 400 g of methanol as a slurry, then filtered and dried at 50 ° C. for 17 hours to obtain a white powder polymer (73 g, yield 73%). . This polymer has Mw of 5700, Mw / Mn of 1.7, and as a result of 13C-NMR analysis, as a result of analysis of each repeating unit derived from compound (M-1), compound (M-2), and compound (M-3). It was a copolymer having a content ratio of 51.4: 14.6: 34.0 (mol%). This is referred to as a polymer (D-2).

Acid generator (E) E-1: Triphenylsulfonium nonafluoro-n-butanesulfonate E-2: 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium nonafluoro-n-butanesulfonate Diffusion controller (F) F-1: R-(+)-(tert-butoxycarbonyl) -2-piperidinemethanol solvent (G) G-1: propylene glycol monomethyl ether acetate G-2: cyclohexanone

The radiation sensitive resin composition (D) used in this example was prepared with the composition shown in Table 1.

[Preparation of Upper Layer Film-Forming Composition] Next, the polymers (A-1), (A-2), (A ′), (B-1), and (C-1), and the solvents shown below. (H) was mixed with the composition shown in Table 2, and the solid content concentration was adjusted to 1.4 mass%. Then, it filtered with the filter of the hole diameter 200nm, and prepared the upper film | membrane formation composition.

[Solvent (S)]: (S-1): 4-methyl-2-pentanol (S-2): diisoamyl ether

(Example 1) 30 parts of the polymer (A-1) as the polymer (A), 70 parts of the polymer (B-1) as the polymer (B), and solvent (alcohol having 4 to 10 carbon atoms) 4-methyl-2-pentanol (shown as “solvent (S-1)” in Table 3) 5634 parts, diisoamyl ether (in Table 3, “alkyl ether having an alkyl chain having 4 to 10 carbon atoms)” 1409 parts) (shown as “Solvent (S-2)”), and the mixture was stirred for 2 hours, and then filtered through a filter having a pore size of 200 nm, whereby an upper layer film-forming composition having a solid content concentration of 1.4% by mass (Example 1) ) Was prepared. Various evaluations shown below were performed on this upper layer film-forming composition.

[Evaluation Method]: (1) Evaluation Method of Upper Layer Film Removability (Removability): Using a trade name “CLEAN TRACK ACT8” (manufactured by Tokyo Electron Ltd.) on an 8-inch silicon wafer, an upper layer film forming composition The film was spin-coated and baked at 90 ° C. for 60 seconds to form a coating film (upper layer film) having a thickness of 90 nm. The thickness (film thickness) of the coating film was measured using a trade name “Lambda Ace VM90” (Dainippon Screen). Paddle development (developer: 2.38% TMAH aqueous solution) was performed for 60 seconds using a trade name “CLEAN TRACK ACT8”, spin-dried by shaking, and the wafer surface was observed. The evaluation was “◯” if the wafer surface was developed without any residue, and “X” if the residue was observed on the wafer surface. The evaluation results are shown in Table 4. In Table 4, “Removability” indicates this evaluation.

(2) Method for measuring receding contact angle: First, an upper layer film-forming composition is spin-coated on an 8-inch silicon wafer, and PB is performed at 90 ° C. for 60 seconds on a hot plate to form a coating film having a thickness of 30 nm. did. Thereafter, using the trade name “DSA-10” (manufactured by KRUS), the receding contact angle was measured immediately under the environment of room temperature: 23 ° C., humidity: 45%, and normal pressure by the following procedure.

The wafer stage position of the product name “DSA-10” (manufactured by KRUS) is adjusted, and the wafer is set on the adjusted stage. Next, water is injected into the needle, and the position of the needle is finely adjusted to an initial position where water droplets can be formed on the set wafer. Thereafter, water is discharged from the needle to form a 25 μL water droplet on the wafer. The needle is once withdrawn from the water droplet, and the needle is pulled down again to the initial position and placed in the water droplet. Subsequently, a water droplet is sucked with a needle at a speed of 10 μL / min for 90 seconds, and at the same time, the contact angle is measured once per second (90 times in total). Of these, the average value for the contact angle for 20 seconds from the time when the measured value of the contact angle was stabilized was calculated as the receding contact angle (°). The evaluation results are shown in Table 4. In Table 4, “retraction contact angle” indicates this evaluation.

(3) Measuring method of advancing contact angle: First, a radiation sensitive resin composition (α) is spin-coated on an 8-inch silicon wafer, PB is performed at 90 ° C. for 60 seconds on a hot plate, and the film thickness is 120 nm. A coating film (photoresist film) was formed. Thereafter, using the trade name “DSA-10” (manufactured by KRUS), the advancing contact angle was quickly measured by the following procedure in an environment of room temperature: 23 ° C., humidity: 45%, and normal pressure.

The wafer stage position of the product name “DSA-10” (manufactured by KRUS) is adjusted, and the wafer is set on the adjusted stage. Next, water is injected into the needle, and the position of the needle is finely adjusted to an initial position where water droplets can be formed on the set wafer. Thereafter, water is discharged from the needle to form a 15 μL water droplet on the wafer. The needle is once withdrawn from the water droplet, and the needle is pulled down again to the initial position and placed in the water droplet. Subsequently, water droplets are ejected by the needle at a speed of 10 μL / min for 90 seconds, and at the same time, the contact angle is measured once per second (90 times in total). Among these, the average value for the contact angle for 20 seconds from the time when the measured value of the contact angle was stabilized was calculated to be the forward contact angle (°). The evaluation results are shown in Table 4. In Table 4, “advance contact angle” indicates this evaluation.

(4) Evaluation method of intermixing (intermixing): This evaluation was performed to evaluate that intermixing with the photoresist film is prevented. First, the radiation-sensitive resin composition (α) was spin-coated on an 8-inch silicon wafer that had been previously subjected to HMDS treatment (100 ° C., 60 seconds) using a trade name “CLEAN TRACK ACT8”. PB was performed at 90 ° C. for 60 seconds on a hot plate to form a coating film (photoresist film) having a thickness of 120 nm. On the formed coating film, the upper layer film-forming composition was spin-coated, and PB (90 ° C., 60 seconds) was performed to form a coating film having a thickness of 30 nm. Ultra pure water was discharged onto the wafer for 60 seconds from a rinse nozzle with a trade name of “CLEAN TRACK ACT8”, and spin-drying was performed at 4000 rpm for 15 seconds. Next, using the trade name “CLEAN TRACK ACT8”, paddle development (developing solution: 2.38% TMAH aqueous solution) was performed for 60 seconds with an LD nozzle to remove the upper layer film. Although the upper layer film is removed by the above development, the photoresist film remains as it is because it is not exposed. Before and after development, the film thickness of the photoresist film is measured using the trade name “Lambda Ace VM90” (Dainippon Screen Co., Ltd.). If the change rate of the film thickness is within 5%, the photoresist film In other words, it was judged that there was no intermixing between the upper film and the film was evaluated as “◯”, and when the film thickness change rate exceeded 5%, it was evaluated as “x”. The evaluation results are shown in Table 4. In Table 4, “Intermixing” indicates this evaluation.

(5) Measurement of Elution Amount (Elution Amount): As shown in FIGS. 2 and 3, HMDS (hexamethyl) was used in a processing condition of 100 ° C. for 60 seconds using “CLEAN TRACK ACT8” (manufactured by Tokyo Electron Ltd.) in advance. Dissilazane) An 8-inch silicon wafer 3 having a treatment layer 4 was prepared. A silicon rubber sheet (manufactured by Kureha Elastomer Co., Ltd., thickness: 1.0 mm, shape: 30 cm per side) on the surface of the 8-inch silicon wafer 3 on the side of the HMDS treatment layer, the center of which is cut out into a circular shape with a diameter of 11.3 cm Square) 5 was placed. At this time, the central portion (the cut-out portion 6) where the silicon rubber sheet 5 was cut out was positioned at the center of the 8-inch silicon wafer 3. Next, 10 mL of ultrapure water 7 was filled in the cut-out portion 6 of the silicon rubber sheet 5 using a 10 mL hole pipette.

On the other hand, an 8-inch silicon wafer 10 different from the 8-inch silicon wafer 3 on which the lower-layer antireflection film 8, the resist film 11 and the upper-layer film 9 are formed in advance is prepared, and the 8-inch silicon wafer 10 is used as the upper layer. The film 9 was placed so as to be positioned on the silicon rubber sheet 5 side, that is, while the upper film 9 and the ultrapure water 7 were in contact with each other, the ultrapure water 7 was not leaked.

The lower antireflection film 8, the resist film 11 and the upper film 9 on the other 8-inch silicon wafer 10 were formed as follows. First, a composition for a lower antireflection film (“ARC29A”, manufactured by Brewer Science) was applied using the “CLEAN TRACK ACT8” so as to form a lower antireflection film having a thickness of 77 nm. Next, the radiation sensitive resin composition (α) is spin-coated on the lower antireflection film using the “CLEAN TRACK ACT8” and baked at 115 ° C. for 60 seconds to form a resist having a thickness of 205 nm. A coating 11 was formed. Thereafter, the upper film forming composition was applied onto the resist film 11 to form an upper film 9.

After placing the upper layer film 9 so as to be positioned on the silicon rubber sheet 5 side, the state was kept for 10 seconds. Thereafter, the other 8-inch silicon wafer 10 was removed, and the ultrapure water 7 that had been in contact with the upper layer film 9 was collected with a glass syringe. This ultrapure water 7 was used as a sample for analysis. Note that the recovery rate of the ultrapure water 7 filled in the cut-out portion 6 of the silicon rubber sheet 5 was 95% or more.

Subsequently, the peak intensity of the anion part of the photoacid generator in the obtained sample for analysis (ultra pure water) was measured by LC-MS (liquid chromatograph mass spectrometer) (LC part: “SERIES1100” manufactured by AGILENT, MS part: “Mariner” manufactured by Perseptive Biosystems, Inc.) under the following measurement conditions. At that time, with respect to the photoacid generator used in the radiation-sensitive resin composition (α), each of the peak intensities of the 1 ppb, 10 ppb, and 100 ppb aqueous solutions was measured under the same conditions as the measurement conditions of the analytical sample, and a calibration curve was obtained. It was created. Using this calibration curve, the elution amount (of the anion portion) of the photoacid generator with respect to water was calculated.

Similarly, a calibration curve was prepared by measuring the peak intensities of the 1 ppb, 10 ppb, and 100 ppb aqueous solutions under the same conditions as those for the analytical sample. Using this calibration curve, the elution amount of the acid diffusion controlling agent with respect to water was calculated. The elution amount was evaluated when the sum of the calculated elution amount of the anion portion of the photoacid generator and the elution amount of the acid diffusion controller was 5.0 × 10 ⁻¹² mol / cm ² or more. When it was “×” or 5.0 × 10 ⁻¹² mol / cm ² or less, “◯” was given. The evaluation results are shown in Table 4. In Table 4, “Elution” indicates this evaluation.

(Measurement conditions) Column used: “CAPCELL PAK MG”, manufactured by Shiseido Co., Ltd., 1 flow rate: 0.2 ml / min, Outflow solvent: 0.1% by mass of formic acid was added to water / methanol (3/7) Measurement temperature: 35 ° C

(6) Blob defect evaluation method: An 8-inch silicon wafer that has been subjected to HMDS (hexamethyldisilazane) treatment at 100 ° C. for 60 seconds in advance using “CLEAN TRACK ACT8” (manufactured by Tokyo Electron Ltd.) is prepared. did. The 8-inch silicon wafer was spin-coated with the radiation-sensitive resin composition (α), and PB was performed at 90 ° C. for 60 seconds on a hot plate to form a coating film having a thickness of 120 nm. The upper layer film-forming composition was spin-coated on this coating film, and PB (90 ° C., 60 seconds) was performed to form a coating film having a thickness of 30 nm. Then, it exposed through the frosted glass in which the pattern is not formed. This 8-inch silicon wafer was used for evaluation of blob defects (blob defects).

First, ultrapure water was discharged from a rinse nozzle of “CLEAN TRACK ACT8” for 60 seconds on the upper layer film of the 8-inch silicon wafer, and spin drying was performed by shaking off at 4000 rpm for 15 seconds. Next, paddle development was performed for 60 seconds with the LD nozzle of “CLEAN TRACK ACT8”, and the upper layer film was removed. In this paddle development, a 2.38% TMAH aqueous solution was used as a developer. After development, the degree of undissolved upper layer film was measured with “KLA2351” (manufactured by KLA Tencor) to determine blob defects. The evaluation of the blob defect was “◯” when the number of development peeling defects (blob defects) detected was 200 or less, and “X” when the number exceeded 200. The evaluation results are shown in Table 4. In Table 4, “BloB defect” indicates this evaluation.

(7) Patterning evaluation: This evaluation was performed to evaluate the formation of a high-resolution resist pattern. First, a composition for a lower antireflection film (trade name “ARC29A”, manufactured by Brewer Science) was spin-coated on an 8-inch silicon wafer using a trade name “CLEAN TRACK ACT8”, and PB (205 ° C. , 60 seconds) to form a 77 nm-thickness coating film (lower antireflection film). A radiation-sensitive resin composition (α) was spin-coated on the formed lower antireflection film, and PB (90 ° C., 60 seconds) was performed to form a coating film (photoresist film) having a thickness of 120 nm.

An upper layer film-forming composition was spin-coated on the formed photoresist film, and PB (90 ° C., 60 seconds) was performed to form a 30 nm-thick coating film (upper layer film). Next, using an ArF projection exposure apparatus (model number “S306C”, manufactured by Nikon Corporation), exposure is performed under optical conditions of NA: 0.78, sigma: 0.85, 2/3 Ann, and trade name “CLEAN TRACK ACT8” From the rinse nozzle, ultrapure water was discharged onto the wafer for 60 seconds, and spin-drying was performed at 4000 rpm for 15 seconds. After that, PEB (115 ° C., 60 seconds) was performed using a hot plate of the trade name “CLEAN TRACK ACT8”, and then paddle development (developer: 2.38% TMAH aqueous solution) was performed for 30 seconds using an LD nozzle. It was. After rinsing with ultra pure water, spin drying was performed by shaking off at 4000 rpm for 15 seconds.

With respect to the formed resist pattern, the exposure amount for forming a line-and-space pattern (1L1S) having a line width of 90 nm in a one-to-one line width was determined as the optimum exposure amount. For the measurement, a scanning electron microscope (trade name “S-9380”, manufactured by Hitachi Keiki Co., Ltd.) was used. Further, the cross-sectional shape of the line-and-space pattern having a line width of 90 nm was observed with a scanning electron microscope (model number “S-4200”, manufactured by Hitachi Keiki Co., Ltd.). FIG. 1 is a cross-sectional view schematically showing the shape of a line and space pattern. The line width Lb in the middle of the film of the pattern 2 formed on the substrate 1 and the line width La in the upper part of the film were measured, and 0.9 ≦ (La−Lb) /Lb≦1.1. The case was evaluated as “X” when “O”, (La−Lb) / Lb <0.9, or (La−Lb) / Lb> 1.1. The evaluation results are shown in Table 4. In Table 4, “Patterning” indicates this evaluation.

(8) Defect Performance (Watermark Defect and Bubble Defect): As a substrate, a 12-inch silicon wafer having a 77 nm-thick lower layer antireflection film (“ARC29A”, manufactured by Brewer Science) on the surface was used. Note that “CLEAN TRACK ACT12” (manufactured by Tokyo Electron Ltd.) was used for the formation of the lower antireflection film.

A radiation sensitive resin composition (α) was spin-coated on the substrate by the CLEAN TRACK ACT12, and then a PB (90 ° C., 60 seconds) film thickness of 120 nm was obtained. Then, after spin-coating the upper film | membrane formation composition solution on the photoresist film, the coating film (upper film | membrane) with a film thickness of 30 nm was obtained by PB (90 degreeC, 60 second). Next, a mask pattern is formed using an ArF excimer laser immersion exposure apparatus (“ASML AT1250i”, manufactured by ASML) under the conditions of NA = 0.85, σ ₀ / σ ₁ = 0.96 / 0.76, and Annular. The exposure was carried out. At this time, pure water was placed as an immersion solvent between the upper surface of the resist (photoresist film) and the immersion exposure machine lens. Then, after baking at PB (115 ° C., 60 seconds), development was performed at 23 ° C. for 60 seconds with a 2.38 mass% tetramethylammonium hydroxide aqueous solution, washed with water, and dried to form a positive resist pattern. Formed. At this time, an exposure amount for forming a line-and-space pattern (1L1S) having a line width of 100 nm with a one-to-one line width was defined as an optimum exposure amount, and this optimum exposure amount was defined as sensitivity. For this measurement, a scanning electron microscope (“S-9380”, manufactured by Hitachi High-Technologies Corporation) was used.

Thereafter, the defect performance on a line and space pattern (1L1S) having a line width of 100 nm was measured using “KLA2351” manufactured by KLA-Tencor. Specifically, the defect measured by “KLA2351” is observed using a scanning electron microscope (“S-9380”, manufactured by Hitachi High-Technologies Corporation), and is expected to be derived from ArF excimer laser immersion exposure. A watermark defect (water-mark defect) and a bubble defect were distinguished. And the number of those was measured and it was set as the defect performance. The results are shown in Table 3. The evaluation of the watermark defect is “◯” when the number of detected watermark defects is less than 50, “Δ” when the number is 50 or more and less than 100, and “X” when the number exceeds 100. The evaluation results are shown in Table 3. In Table 3, “watermark defect” indicates this evaluation. The evaluation of bubble defects was “◯” when the number of detected bubble defects was 50 or less, “Δ” when the number was 50 or more and less than 100, and “X” when the number exceeded 100. The evaluation results are shown in Table 4. In Table 4,
“Bubble defects” indicate this evaluation.

The upper layer film formed from the upper layer film-forming composition of this example has a removability of “◯”, a receding contact angle of 75.0 °, an advancing contact angle of 92.0 °, and intermixing. “O”, elution “O”, BloB defect “O”, patterning “O”, watermark defect “O”, bubble defect “O”. It was.

(Example 2 , Reference Examples 3, 4, Examples 5-7, Comparative Examples 1-3) After preparing the upper layer film-forming composition solution in the same manner as in Example 1 except that the composition shown in Table 3 was used. An upper layer film was formed. Various evaluations were performed on this upper layer film. Table 4 shows the obtained results.

As is apparent from Table 4, the upper film compositions of Examples 1 and 2, Reference Examples 3 and 4, and Examples 5 to 7 can form an immersion upper film capable of suppressing the generation of watermark defects and bubble defects. Met. This is considered to be because the balance between the receding contact angle and the advancing contact angle with respect to water of the upper layer film is excellent. In particular, Examples 1 and 2 and Reference Examples 3 and 4 in which the content of the repeating unit (3) in the polymer (A) and the content of the polymer (A) in all polymer components are within the preferred range . The upper layer film of Example 5 was preferable because it was able to highly suppress watermark defects and bubble defects. In addition, it was confirmed that the upper layer film compositions of Examples 1 and 2, Reference Examples 3 and 4, and Examples 5 to 7 had no problem in evaluation of blobs with good intermixing, elution, and patterning. It was confirmed that the film has practical performance. On the other hand, the watermark defect or bubble defect became "x" about the upper layer film composition of Comparative Examples 1-3 which does not contain the polymer (A) of this invention.

Since the upper layer film-forming composition of the present invention contains the polymer (A), it protects the photoresist film during immersion exposure and maintains a stable film without eluting into a medium such as water. The formation of an upper layer film capable of effectively suppressing the occurrence of defects such as watermark defects, bubble defects, pattern defect defects, and the like and capable of forming a high-resolution resist pattern and having a sufficiently high receding contact angle. Can do. Therefore, in the future, even when forming a resist pattern at a high scanning speed, it is possible to effectively suppress the occurrence of defects such as watermark defects and bubble defects. Therefore, the upper layer film-forming composition of the present invention can form an upper layer film that can be suitably used for immersion exposure, and is extremely suitable for a semiconductor device manufacturing process that is expected to be further miniaturized in the future. Can be used.

Claims (8)

At least one selected from the group consisting of the repeating unit represented by the following general formula (1-1) and the repeating unit represented by (1-2), the repeating unit represented by the following general formula (2) and the following general A polymer (A) containing a repeating unit represented by the formula (3);
Contains at least one selected from the group consisting of the repeating unit represented by the following general formula (1-1) and the repeating unit represented by (1-2), and a repeating unit represented by the following general formula (4) A polymer (B)
A composition for forming a liquid immersion upper layer film comprising a solvent (S).

(In the general formulas (1-1) and (1-2), R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group. R ² and R ³ are each independently a single bond or a C 1-6 carbon atom. A linear or branched divalent hydrocarbon group or an alicyclic divalent hydrocarbon group having 4 to 12 carbon atoms, wherein R ⁴ is a carbon number in which at least one hydrogen atom is substituted with a fluorine atom. 1 to 12 linear or branched monovalent hydrocarbon group, or an alicyclic monovalent hydrocarbon group having 3 to 20 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom. )

(In the general formula (2), R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group, and R ⁵ represents a linear or branched group having 1 to 12 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom. A monovalent hydrocarbon group in the form of a ring, or an alicyclic monovalent hydrocarbon group having 3 to 20 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom.)

(In the general formula (3), R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group, and R ⁶ represents a linear or branched monovalent hydrocarbon group having 1 to 12 carbon atoms, or the number of carbon atoms. 3 to 20 alicyclic monovalent hydrocarbon groups are shown.)

(In General Formula (4), R ¹ represents a hydrogen atom, a methyl group, or a trifluoromethyl group, and R ¹⁰ represents a single bond or a linear or branched divalent divalent having 1 to 6 carbon atoms. Indicates a hydrocarbon group.)   The composition for forming a liquid immersion upper layer film according to claim 1, wherein the ratio of the repeating unit represented by the general formula (3) is 1 to 60 mol% with respect to all the repeating units of the polymer (A). . 3. The composition for forming a liquid immersion upper layer film according to claim 1, wherein, in the general formula (3), R ⁶ is an alicyclic monovalent hydrocarbon group having 3 to 20 carbon atoms. At least 1 of the repeating unit represented by the following general formula (5-1), the repeating unit represented by the following general formula (5-2), and the repeating unit represented by the following general formula (5-3) The composition for liquid immersion upper film formation as described in any one of Claim 1 to 3 which further contains the polymer (C) containing a seed | species and the repeating unit represented by the said General formula (4).

(In the general formulas (5-1) to (5-3), each R ¹ independently represents a hydrogen atom, a methyl group or a trifluoromethyl group, and each of R ¹² and R ¹³ independently represents one having 1 to 6 carbon atoms. A linear or branched divalent hydrocarbon group or a divalent alicyclic hydrocarbon group having 4 to 12 carbon atoms is shown.) The polymer (A) is a repeating unit represented by the general formula (1-1), a repeating unit represented by the general formula (2), and a repeating unit represented by the general formula (3). The polymer (B) contains a repeating unit represented by the general formula (1-1) and a repeating unit represented by the general formula (4), The liquid immersion upper layer according to claim 4, wherein the polymer (C) contains a repeating unit represented by the general formula (4) and a repeating unit represented by the general formula (5-1). Film forming composition. The composition for forming a liquid immersion upper layer film according to claim 5 , wherein the content of the polymer (A) is 20 to 60% by mass when the total amount of the polymer is 100% by mass. A liquid immersion upper film comprising the liquid upper film formation composition according to any one of claims 1 to 6 . A step (1) of applying a photoresist composition on a substrate to form a photoresist film;
Applying the composition for forming a liquid immersion upper layer film according to any one of claims 1 to 6 on the photoresist film to form an upper layer film on the photoresist film;
An immersion medium is disposed on the upper layer film, and the upper layer film and the photo resist film are irradiated with exposure light having passed through a mask having a predetermined pattern and an immersion liquid, and thereby the upper layer film and the photo film. A step (3) of exposing the resist film;
Developing the exposed upper layer film and the photoresist film with a developer (4);
A resist pattern forming method comprising: