JP5652404B2 - Radiation sensitive composition and resist pattern forming method - Google Patents

Description

  The present invention relates to a radiation-sensitive composition and a resist pattern forming method. More particularly, the present invention relates to a radiation-sensitive composition that can be used in a double patterning process and can be used in an immersion exposure process such as water without separately forming an upper layer film, and a resist pattern forming method using the same. .

  In the field of microfabrication represented by the manufacture of integrated circuit elements, in order to obtain a higher degree of integration, recently, lithography technology capable of microfabrication at a level of 0.10 μm or less is required. In the future, it is required to form a finer pattern (for example, a fine resist pattern having a line width of about 45 nm). As means for forming such a fine pattern, it is conceivable to shorten the wavelength of the light source of the exposure apparatus (ArF excimer laser (wavelength: 193 nm)) or increase the numerical aperture (NA) of the lens. However, in order to shorten the light source wavelength, a new expensive exposure apparatus is required. In addition, the increase in the numerical aperture (NA) of the lens has a problem that the depth of focus decreases even if the resolution is increased because the resolution and the depth of focus are in a trade-off relationship.

  Recently, an immersion exposure (liquid immersion lithography) method has been reported as a lithography technique capable of solving such a problem. However, it is said that the advancement of the exposure technique by the immersion exposure method is limited to 45 nm half pitch (hp), and technical development for the 32 nm hp generation that requires further fine processing is being carried out. In recent years, a double exposure technique such as double patterning (DP) or double exposure (DE) has been proposed in accordance with the demand for higher density and higher density of devices using lithography technology for forming fine patterns ( For example, refer nonpatent literature 1). In this technique, 32 nm LS can be patterned by superposing sparse line patterns or isolated trench patterns with a half-cycle shift.

  Note that DP is a technique in which a resist film is separately formed on a first resist pattern formed by exposing and developing a resist layer, and a second resist pattern is formed by exposing and developing. Say. DE refers to a technique for forming a resist pattern by exposing a resist layer to the same resist layer continuously without developing it and then developing the resist layer.

As an example of a technique for patterning 32 nm LS, Non-Patent Document 2 discloses forming a 32 nm line with a 1: 1 pitch. Specifically, first, a 32 nm line having a pitch of 1: 3 is formed, and a hard mask (hereinafter also referred to as “HM”) such as SiO ₂ is processed by etching. Thereafter, a 32 nm line having a pitch of 1: 3 is similarly formed at a position shifted from the first resist pattern by a half cycle, and HM is processed again by etching.

SPIE 2006 61531K 3rd International Symposium on Immersion Lithography PO-11

  However, although there are some proposed processes such as Non-Patent Documents 1 and 2, there has not yet been proposed a specific material that can be suitably used for the double patterning process using such an immersion exposure process. The current situation is not. In addition, in the proposed process, after forming the first resist pattern, when forming the second resist pattern, the first resist pattern may be deformed, and the accuracy of the pattern shape and dimensions is reduced. There's a problem.

  Furthermore, when exposing the first resist layer formed of the first radiation-sensitive composition or the second resist layer formed of the second radiation-sensitive composition, the resist layer is usually immersed in the liquid. In order to avoid lens contamination due to elution into the liquid, it was necessary to use an upper film for immersion. However, when the upper layer film for immersion is formed, there is a problem that the throughput deteriorates as the number of steps increases.

  The present invention has been made in view of such problems of the prior art, and the problem is that the present invention is used for a double patterning process, and an upper layer film is separately provided for an immersion exposure process such as water. The object is to provide a radiation-sensitive composition that can be used without being formed.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors can achieve the above-mentioned problems by including, as a constituent component, a repeating unit having a crosslinking group and a polymer containing a repeating unit having a fluorine atom. The inventors have found that this is possible and have completed the present invention.

  That is, according to the present invention, the following radiation sensitive composition and resist pattern forming method are provided.

[1] A step (1) of forming a first resist pattern on a substrate using the first radiation-sensitive composition, and the first resist pattern with respect to the second radiation-sensitive composition And insolubilizing step (2), and using the second radiation-sensitive composition, forming a second resist pattern on the substrate on which the first resist pattern is formed (3), (A) a polymer containing a repeating unit having an acid labile group (hereinafter also referred to as “polymer (A)”), and (B) a crosslinking group, which is used in the step (1) of the resist pattern forming method comprising A polymer containing a repeating unit having a fluorine atom and a repeating unit having a fluorine atom (hereinafter also referred to as “polymer (B)”), and (C) a radiation-sensitive acid generator (hereinafter referred to as “acid generator (C)”. "and also referred to), containing, and (D) a solvent, wherein the crosslinking There the first resist pattern, a cross-linking group for insoluble in the second radiation-sensitive composition, a radiation-sensitive composition.

  [2] The radiation-sensitive composition according to [1], wherein the polymer (B) is contained in an amount of 1 to 80 parts by mass with respect to 100 parts by mass of the polymer (A).

  [3] The radiation-sensitive composition according to [1] or [2], wherein the crosslinking group is a thermosetting reactive group.

  [4] The polymer (B) is a repeating unit represented by at least one of a repeating unit represented by the following general formula (1-1) and a repeating unit represented by the following general formula (1-2). (1) The radiation-sensitive composition according to any one of [1] to [3], including (hereinafter, also referred to as “repeating unit (1)”).

（前記一般式（１−１）及び（１−２）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す。前記一般式（１−１）中、Ｒ^２は、メチレン基、エチレン基又はプロピレン基を示す。Ｒ^３は、下記一般式（２）又は（３）で表される基を示す。前記一般式（１−２）中、Ｒ^４は、メチレン基又は炭素数２〜６のアルカンジイル基を示す。Ｒ^５は、水素原子、メチル基又はエチル基を示す。ｎは、０又は１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. In the general formula (1-1), R ² represents a methylene group. And R ³ represents a group represented by the following general formula (2) or (3), wherein R ⁴ represents a methylene group or a carbon number. And represents an alkanediyl group of 2 to 6. R ⁵ represents a hydrogen atom, a methyl group or an ethyl group, and n represents 0 or 1.

（前記一般式（２）及び（３）中、複数のＲ^６は、相互に独立に、水素原子、メチル基、エチル基、又は炭素数３〜１０の直鎖状若しくは分岐状のアルキル基を示す。）

(In the general formulas (2) and (3), a plurality of R ⁶ are each independently a hydrogen atom, a methyl group, an ethyl group, or a linear or branched alkyl group having 3 to 10 carbon atoms. Show.)

  [5] The polymer (B) is a repeating unit (2) represented by at least one of the repeating unit represented by the following general formula (4) and the repeating unit represented by the following general formula (5) ( Hereinafter, the radiation-sensitive composition according to any one of [1] to [4], which includes “repeating unit (2)”.

（前記一般式（４）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す。Ｒ^７は、単結合又は炭素数１〜２０の直鎖状、分岐状若しくは環状の、飽和若しくは不飽和の２価の炭化水素基を示す。Ｘは、フッ素原子で置換されたメチレン基又は炭素数２〜２０の直鎖状若しくは分岐状のフルオロアルカンジイル基を示す。Ｒ^８は、水素原子又は１価の有機基を示す。）

(In the general formula (4), R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group. R ⁷ is a single bond or a linear, branched or cyclic saturated group having 1 to 20 carbon atoms. Alternatively, it represents an unsaturated divalent hydrocarbon group, X represents a methylene group substituted with a fluorine atom or a linear or branched fluoroalkanediyl group having 2 to 20 carbon atoms, R ⁸ represents hydrogen It represents an atom or a monovalent organic group.)

（前記一般式（５）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す。Ａは、単結合、エーテル結合、チオエーテル結合、カルボニル基、エステル基、アミド基、スルホンアミド基、ウレタン基を有する２価の有機基を示す。Ｒ^９は、少なくとも一つ以上のフッ素原子を有する、メチル基、エチル基、炭素数３〜６の直鎖状若しくは分岐状のアルキル基、又は炭素数４〜２０の１価の脂環式炭化水素基を示す。）

(In the general formula (5), R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group. A represents a single bond, an ether bond, a thioether bond, a carbonyl group, an ester group, an amide group, or a sulfonamide group. R ⁹ represents a divalent organic group having a urethane group, R ⁹ is a methyl group, an ethyl group, a linear or branched alkyl group having 3 to 6 carbon atoms, having at least one fluorine atom, or A monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms is shown.)

  [6] The radiation sensitive composition according to any one of [1] to [5], wherein the polymer (B) further includes a repeating unit having an acid labile group.

  [7] The above [6], wherein the repeating unit having an acid labile group is a repeating unit (3) represented by the following general formula (6) (hereinafter also referred to as “repeating unit (3)”). Radiation sensitive composition.

（前記一般式（６）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す。Ｒ^１０は、相互に独立に、メチル基、エチル基、炭素数３〜４の直鎖状若しくは分岐状のアルキル基、又は炭素数４〜２０の１価の脂環式炭化水素基を示す。但し、いずれか二つのＲ^１０が相互に結合しそれぞれが結合している炭素原子と共に炭素数４〜２０の２価の脂環式炭化水素基を形成し、残りのＲ^１０がメチル基、エチル基、炭素数３〜４の直鎖状若しくは分岐状のアルキル基、又は炭素数４〜２０の１価の脂環式炭化水素基を示してもよい。）

(In the general formula (6), R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group. R ^{10 s} are each independently a methyl group, an ethyl group, or a straight chain having 3 to 4 carbon atoms. or branched alkyl group, or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms. the number of carbon atoms with one carbon atom to two R ¹⁰ are attached respectively bonded to each other A divalent alicyclic hydrocarbon group of 4 to 20 is formed, and the remaining R ¹⁰ is a methyl group, an ethyl group, a linear or branched alkyl group having 3 to 4 carbon atoms, or a carbon number of 4 to 20 The monovalent alicyclic hydrocarbon group may be shown.)

  [8] The radiation-sensitive composition according to any one of [2] to [7], wherein the polymer (A) does not include a repeating unit having a crosslinking group.

[9] The radiation-sensitive composition according to [4] , wherein the content ratio of the repeating unit (1) is 1 to 30 mol% with respect to a total of 100 mol% of repeating units contained in the polymer (B). object.

[10] The radiation-sensitive composition according to [5] , wherein the content ratio of the repeating unit (2) is 1 to 70 mol% with respect to 100 mol% of the total repeating units contained in the polymer (B). object.

  [11] A step (1) of forming a first resist pattern on a substrate using the radiation-sensitive composition according to any one of [1] to [10], and the first resist A step (2) for insolubilizing the pattern with respect to the second radiation-sensitive composition, and a second pattern on the substrate on which the first resist pattern is formed using the second radiation-sensitive composition. Forming a resist pattern of (3).

  [12] The first resist pattern has a line portion and a space portion, the second resist pattern has a line portion and a space portion, the line portion of the first resist pattern, The resist pattern forming method according to [11], wherein the second resist pattern is formed so that the line portions of the second resist pattern intersect each other.

  [13] The first resist pattern has a line portion and a space portion, the second resist pattern has a line portion and a space portion, and the line portion of the first resist pattern; The resist pattern forming method according to [11], wherein the second resist pattern is formed so that the line portion of the second resist pattern is parallel to the line portion.

  [14] In the step (1), the radiation-sensitive composition is applied onto the substrate to form a first resist layer, and after heating, the first resist layer is used as the outermost surface, and an exposure process is performed. The resist pattern forming method according to any one of [11] to [13], which is a step of forming the first resist pattern.

  [15] After the step (3) is applied, the second radiation-sensitive composition is applied onto the substrate on which the first resist pattern is formed to form a second resist layer, and then heated. The resist pattern forming method according to any one of [11] to [14], which is a step of forming the second resist pattern by exposing the second resist layer to the outermost surface and performing an exposure process.

  The radiation-sensitive composition of the present invention is used in a double patterning process, and has an effect that it can be used in an immersion exposure process such as water without separately forming an upper layer film. .

  According to the resist pattern forming method of the present invention, in the double patterning process, the first resist pattern is insolubilized in the second radiation-sensitive composition during exposure to form the second resist pattern. Therefore, the second resist pattern can be formed while maintaining the shape and dimensions of the first resist pattern. That is, fluctuations in the line width of the first resist pattern can be suppressed. In addition, the resist pattern forming method of the present invention has an effect that it can also be used in an immersion exposure process.

It is a schematic diagram which shows an example of the 1st resist layer formed on the board | substrate in the process (1) of the resist pattern formation method concerning this invention. It is a schematic diagram which shows an example of the exposure state of the 1st resist layer in process (1) of the resist pattern formation method which concerns on this invention. It is a schematic diagram which shows an example of the alkali image development part formed in the 1st resist layer in the process (1) of the resist pattern formation method concerning this invention. It is a schematic diagram which shows an example of the 1st resist pattern formed on the board | substrate in the process (1) of the resist pattern formation method concerning this invention. It is a schematic diagram which shows the insolubilized state of the 1st resist pattern in the resist pattern formation method which concerns on this invention. It is a schematic diagram which shows an example of the 2nd resist layer formed on the board | substrate in process (3) of the resist pattern formation method concerning this invention. It is a schematic diagram which shows an example of the exposure state of a 2nd resist layer in the process (3) of the resist pattern formation method concerning this invention. It is a schematic diagram which shows an example of the alkali image development part formed in the 2nd resist layer in the process (3) of the resist pattern formation method concerning this invention. It is a schematic diagram which shows an example of the 2nd resist pattern formed on the board | substrate in the process (3) of the resist pattern formation method concerning this invention. It is a top view which shows typically an example of the resist pattern formed on the board | substrate in the resist pattern formation method which concerns on this invention. It is a side view which shows typically an example of the resist pattern formed on the board | substrate in the resist pattern formation method which concerns on this invention. It is a top view which shows typically the other example of the resist pattern formed on the board | substrate in the resist pattern formation method which concerns on this invention.

  Embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments. It is understood that the scope of the present invention includes modifications, improvements, and the like as appropriate to the following embodiments based on the ordinary knowledge of those skilled in the art without departing from the spirit of the present invention. Should.

I. Resist pattern formation method:
The resist pattern forming method of the present invention is a method including steps (1) to (3). An embodiment of a resist pattern forming method of the present invention including steps (1) to (3) will be described with reference to the drawings. In this specification, “line pattern” means that the resist pattern is a line-and-space pattern having a line portion and a space portion (hereinafter also referred to as “LS”).

1. Step (1):
1A to 1D are schematic views showing an example of the step (1) in the resist pattern forming method according to the present invention. Step (1) is a step of forming a first resist pattern on the substrate using the first radiation-sensitive composition. Among them, after applying the first radiation-sensitive composition on the substrate and heating to form the first resist layer, other steps such as a step of forming the upper layer film with the resist layer as the outermost surface are performed. It is preferable to perform the exposure process without forming the first resist pattern. This is because the material used for forming the upper layer film can be saved, the number of processes can be reduced, and the throughput can be improved.

  More specifically, first, as shown to FIG. 1A, the 1st resist layer 2 is formed on the board | substrate 1 using a 1st radiation sensitive composition. Next, as shown in FIG. 1B, a mask 4 and a lens 6 having a predetermined pattern are sequentially arranged in a predetermined region, and optionally using an immersion liquid 3 such as water, irradiation of radiation (arrow in the figure). Perform exposure by. Thereby, as shown in FIG. 1C, the alkali developing portion 5 is formed in the first resist layer 2. Thereafter, by developing, as shown in FIG. 1D, a first resist pattern 12 having a line portion 12a and a space portion 12b (space for three lines with respect to 1L3S: one line) is formed on the substrate 1. .

(1) Formation of first resist layer:
The first resist layer can be formed by applying the first radiation-sensitive composition on the substrate. The method for applying is not particularly limited. For example, it can be performed by an appropriate coating method such as spin coating, cast coating, roll coating or the like. In addition, the thickness of the 1st resist layer formed is not specifically limited. Usually, it is 10-1000 nm, and it is preferable that it is 10-500 nm.

  Moreover, after apply | coating a 1st radiation sensitive composition, you may volatilize the solvent in a coating film by prebaking (henceforth "PB (Pre-Bake)") as needed. PB heating conditions are appropriately selected depending on the composition of the first radiation-sensitive composition. Usually, it is about 30-200 degreeC, and it is preferable that it is 50-150 degreeC.

(I) First radiation-sensitive composition:
The first radiation-sensitive composition is the radiation-sensitive composition of the present invention described later.

(Ii) Substrate:
The substrate is not particularly limited. For example, a conventionally known substrate such as a silicon wafer or a wafer coated with aluminum can be used. In order to maximize the potential of the first radiation-sensitive composition, an organic or inorganic antireflection film can be formed on the substrate to be used (for example, Japanese Patent Publication No. 6). -12452 and JP-A-59-93448).

(2) Exposure:
As shown in FIG. 1B, a mask 4 and a lens 6 having a predetermined pattern are sequentially arranged in a predetermined region of the first resist layer 2 and exposure is performed by irradiation with radiation. Thereby, as shown in FIG. 1C, the alkali developing portion 5 is formed in the first resist layer 2. In the exposure, an immersion liquid 3 such as water or a fluorine-based inert liquid may be optionally used.

  The radiation used for exposure is appropriately selected from visible light, ultraviolet light, far ultraviolet light, X-rays, charged particle beams, etc., depending on the type of acid generator (C) contained in the first radiation-sensitive composition. Selected. Among these, far ultraviolet rays represented by ArF excimer laser (wavelength 193 nm) and KrF excimer laser (wavelength 248 nm) are preferable, and far ultraviolet rays by ArF excimer laser (wavelength 193 nm) are particularly preferable.

  Moreover, exposure conditions, such as exposure amount, are suitably selected according to the compounding composition of a 1st radiation sensitive composition, the kind of additive, etc.

  Further, it is preferable to perform a heat treatment (hereinafter also referred to as “PEB (Post-Exposure Bake)”) after exposure. By performing PEB, the dissociation reaction of the acid labile group in the first radiation-sensitive composition can proceed smoothly. The heating conditions for PEB are appropriately selected depending on the composition of the first radiation-sensitive composition. Usually, it is 30-200 degreeC, and it is preferable that it is 50-170 degreeC.

(3) Formation of first resist pattern:
The alkali developing part is dissolved by developing the first resist layer with a developer. Thereby, the 1st resist pattern 12 which has the line part 12a and the space part 12b as shown to FIG. 1D can be formed. In addition, after developing with a developing solution, it is generally washed with water and dried.

  There is no restriction | limiting in particular as a image development method, It can carry out by a conventionally well-known method. Among these, development is preferably performed by a paddle method, an LD nozzle method, a GP nozzle method, or the like.

  Preferable examples of the developer include an alkaline aqueous solution in which at least one alkaline compound such as sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide and the like is dissolved.

  The concentration of the alkaline aqueous solution is usually 10% by mass or less. If the concentration of the alkaline aqueous solution is more than 10% by mass, the unexposed area may be dissolved in the developer. Moreover, the lower limit of the concentration of the alkaline aqueous solution varies depending on the compound used. However, it is usually 0.5% by mass or more. In the present specification, “alkali-insoluble or hardly-soluble alkali” means that 50% or more of the initial film thickness of a film formed only from a polymer is developed after development under an alkali development condition performed when a resist pattern is formed. The remaining properties.

  An organic solvent can also be added to the alkaline aqueous solution. Specific examples of the organic solvent include ketones such as acetone and methyl ethyl ketone; alcohols such as methanol and ethanol; ethers such as tetrahydrofuran and dioxane; esters such as ethyl acetate, n-butyl acetate and i-amyl acetate; toluene In addition to aromatic hydrocarbons such as xylene, phenol, acetonyl acetone, dimethylformamide and the like can be mentioned. In addition, you may use these organic solvents individually by 1 type or in mixture of 2 or more types.

  The use ratio of the organic solvent is preferably 100 parts by volume or less with respect to 100 parts by volume of the alkaline aqueous solution. If the use ratio of the organic solvent is more than 100 parts by volume, the developability may be reduced, and the development residue in the exposed part may increase. Further, an appropriate amount of a surfactant or the like may be added to the developer. Here, the volume is a volume measured at 25 ° C.

2. Step (2):
FIG. 2 is a schematic diagram showing an example of the step (2) in the resist pattern forming method according to the present invention. As shown in FIG. 2, the first resist pattern formed in the step (1) is heated at a temperature of 120 ° C. or higher (preferably 140 ° C. or higher) (hereinafter referred to as “PDB (Post-Development Bake)”). And / or the first resist in which the first resist pattern is insolubilized with respect to the second radiation-sensitive composition by irradiation with radiation (preferably a wavelength of 300 nm or less) (arrow in the figure). Pattern 22 may be used. That is, the first resist pattern 22 is inactivated by heating (PB and PEB in step (3)) and radiation irradiation (exposure in step (3)).

Examples of the radiation irradiation condition include a condition in which radiation is irradiated with an exposure amount 2 to 20 times the optimum exposure amount for forming the first resist pattern. Moreover, as heating conditions, the conditions heated on temperature conditions higher than PEB temperature at the time of forming a 1st resist pattern can be mentioned. Furthermore, as a lamp used for radiation irradiation, a lamp such as an Ar ₂ lamp, a KrCl lamp, a Kr ₂ lamp, a XeCl lamp, or an Xe ₂ lamp (manufactured by Ushio Inc.) can be used. These inactivation methods may be performed alone or in combination of two or more.

  In the present specification, “inactive with respect to light” means that the radiation-sensitive composition does not change from insoluble to soluble in an alkaline aqueous solution even by exposure by irradiation with radiation or the like. . That is, the first resist pattern 22 does not become alkali-soluble even when exposed. Further, “inert to heat” means that deformation such as decomposition and melting does not occur by heating when forming the second resist pattern using the second radiation-sensitive composition. That is, the pattern shape does not disappear by heating.

3. Step (3):
Step (3) is a step of forming a second resist pattern on the substrate on which the first resist pattern is formed using the second radiation-sensitive composition. In particular, after the second radiation-sensitive composition is applied on the substrate on which the first resist pattern is formed and heated to form the second resist layer, the resist layer is formed in the same manner as in step (1). It is preferably a step of forming a second resist pattern by performing an exposure process without performing other steps such as a step of forming an upper layer film as the outermost surface. This is because the material used for forming the upper layer film can be saved, the number of processes can be reduced, and the throughput can be improved.

  More specifically, first, as shown in FIG. 3A, the second resist layer 32 is formed on the substrate 1 on which the first resist pattern 22 is formed using the second radiation-sensitive composition. . Next, as shown in FIG. 3B, a mask 4 and a lens 6 having a predetermined pattern are sequentially arranged on the second resist layer 32 and, optionally, an immersion liquid 33 such as water is used to irradiate radiation (see FIG. 3B). (3B arrow) exposure is performed. Thereby, as shown in FIG. 3C, the alkali developing portion 35 is formed in the second resist layer 32. Finally, as shown in FIG. 3D, the second resist pattern (second line portion 42a) is formed on the same surface of the substrate 1 on which the first resist pattern 22 is formed. Form.

(1) Formation of second resist layer:
The second resist layer can be formed by applying the second radiation-sensitive composition onto the substrate on which the first resist pattern is formed. The method for applying is not particularly limited. For example, it can be performed by an appropriate coating method such as spin coating, cast coating, roll coating or the like. The thickness of the second resist layer is not particularly limited. Usually, it is 10-1000 nm, and it is preferable that it is 10-500 nm.

  Moreover, after apply | coating a 2nd radiation sensitive composition, you may volatilize the solvent in a coating film by PB as needed. The heating conditions for this PB are appropriately selected depending on the blending composition of the second radiation-sensitive composition. Usually, it is about 30-200 degreeC, Preferably it is 50-150 degreeC.

  The second radiation sensitive composition will be described later. In addition, the same solvent may be sufficient as the solvent contained in a 1st radiation sensitive composition and a 2nd radiation sensitive composition, and a different solvent may be sufficient as it. This is because the first resist pattern is inactivated with respect to heat or light by performing the step (2), and is insolubilized with respect to the second radiation-sensitive composition. Therefore, the second resist layer can be formed without mixing with the first resist pattern.

(2) Exposure:
Next, in this step (3), as shown in FIG. 3B, a mask 4 and a lens 6 having a predetermined pattern are sequentially arranged on the substrate 1 on which the second resist layer 32 is formed, and exposure by radiation irradiation is performed. Do. Thereby, as shown in FIG. 3C, the alkali developing portion 35 is formed in the second resist layer 32. In the exposure, an immersion liquid 33 such as water or a fluorine-based inert liquid may be optionally used. In addition, exposure can be performed on the exposure conditions mentioned above at the process (1).

(3) Development:
By developing after the exposure, as shown in FIG. 3D, a second resist pattern (second line portion 42a) is formed on the substrate 1 on which the first resist pattern 22 is formed. In addition, about the image development method, it can carry out with the image development method mentioned above at the process (1).

  Thus, 1L1S (the ratio of the width of the line portion and the space portion) in which the first resist pattern and the second resist pattern are alternately arranged on the substrate by double patterning as in the steps (1) to (3). 1: 1) can be formed.

  Further, for example, a resist pattern (contact hole pattern 15) as shown in FIG. 4 can be formed by double patterning. The resist pattern includes a first line portion 42a of the second resist pattern 42 formed in the step (3), and the first line portion 22a of the first resist pattern 22 is orthogonal to the first line portion 42a. This is performed by forming the resist pattern 22 on the first line portion 22a.

  Further, for example, a resist pattern (contact hole pattern 15) as shown in FIG. 6 can be formed by double patterning. This resist pattern is formed by forming the second resist pattern 42 formed in the step (3) in the space 22 b of the first resist pattern 22. Further, the resist pattern is formed in a lattice shape partitioned by the first line portion 22 a of the first resist pattern 22 and the second line portion 42 a of the second resist pattern 42.

  By using the resist pattern forming method of the present invention, that is, double patterning, a finer line pattern or a finer contact hole can be formed (hereinafter, obtained by the resist pattern forming method (double patterning) of the present invention. A resist pattern (a line pattern or a contact hole pattern) is also referred to as a “DP pattern”).

  In the resist pattern forming method of the present invention, as shown in FIGS. 4 to 6, the first resist pattern 22 has a line portion 22 a and the second resist pattern 42 has a line portion 42 a orthogonal to each other. It is also preferable to form the second resist pattern 42 on the resist pattern 22.

  In the case of forming the contact hole pattern as described above, the width of the line portion and the space portion is preferably 40 to 100 nm (1L1S), more preferably 40 to 65 nm (1L1S), More preferably, it is 40-50 nm (1L1S).

II. Radiation sensitive composition:
In the radiation-sensitive composition, an acid labile group present in the composition is dissociated by the action of an acid generated from the radiation-sensitive acid generator upon exposure to generate a carboxy group. As a result, the exposed portion becomes highly soluble in an alkali developer, and is dissolved and removed by the alkali developer, so that a resist pattern can be formed. That is, the radiation-sensitive composition is a composition containing an alkali-insoluble or hardly soluble polymer that becomes alkali-soluble by the action of an acid, a radiation-sensitive acid generator, and a solvent. Hereinafter, the first radiation-sensitive composition used in forming the first resist layer, which is the radiation-sensitive composition of the present invention, and the second used in forming the second resist layer. The radiation-sensitive composition is described separately.

1. First radiation sensitive composition:
A 1st radiation sensitive composition contains a polymer (A), a polymer (B), an acid generator (C), and (D) solvent. In particular, after forming the first resist pattern, the first resist pattern is inactivated against light or heat by irradiation with radiation having a wavelength of 300 nm or less and / or by heating at 140 ° C. or higher. It is preferable to make it. This first resist pattern has resistance to the second radiation-sensitive composition. Therefore, it remains without being damaged when the second resist pattern is formed.

  In addition, the “acid labile group” in the present specification refers to a group that is dissociated by an acid, and does not mean a particularly different group. A polymer insoluble or hardly soluble in an alkali developer having an acid labile group is dissociated by the action of an acid to become a carboxy group, and a polymer soluble in an alkali developer.

(1) Polymer (A):
The polymer (A) contains (A) a repeating unit having an acid labile group, and preferably does not contain a repeating unit having a crosslinking group. The 1st radiation sensitive composition can form the 1st resist layer which melt | dissolves with respect to an alkali developing solution by the effect | action of an acid by containing a polymer (A). The repeating unit having a crosslinking group will be described later in “(2) Polymer (B)”.

  As a suitable example of the polymer (A), at least one lactone selected from the group consisting of the repeating unit (3) and general formulas (7-1) to (7-5) and formula (7-6) Some include a repeating unit having a structure or a repeating unit represented by the general formula (8) (hereinafter also referred to as “repeating unit (4)”).

（一般式（７−１）中、Ｒ^１１は、水素原子又は炭素数１〜４の置換されていてもよいアルキル基を示す。ｐは、１〜３の整数を示す。一般式（７−４）及び（７−５）中、Ｒ^１２は、水素原子又はメトキシ基を示す。一般式（７−２）及び（７−３）中、Ａは、単結合又はメチレン基を示す。ｍは、０又は１を示す。一般式（７−３）及び（７−５）中、Ｂは、酸素原子又はメチレン基を示す。）

(In General Formula (7-1), R ¹¹ represents a hydrogen atom or an optionally substituted alkyl group having 1 to 4 carbon atoms. P represents an integer of 1 to 3. General Formula (7- In 4) and (7-5), R ¹² represents a hydrogen atom or a methoxy group, and in formulas (7-2) and (7-3), A represents a single bond or a methylene group, m represents , 0 or 1. In general formulas (7-3) and (7-5), B represents an oxygen atom or a methylene group.

（一般式（８）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す。Ｒ^Ｃ１は、単結合又は２価の連結基を示す。Ｒ^Ｃｃは、環状カーボネート構造を有する１価の有機基を示す。）

(In General Formula (8), R ¹ represents a hydrogen atom, a methyl group, or a trifluoromethyl group. R ^C1 represents a single bond or a divalent linking group. R ^Cc represents 1 having a cyclic carbonate structure. Valent organic group.)

（一般式（Ｃｃ−１）中、ｎ_Ｃ１は、０〜２の整数を示す。一般式（Ｃｃ−２）中、ｎ_Ｃ２〜ｎ_Ｃ５は、それぞれ独立に、０〜２の整数を示す。一般式（Ｃｃ−１）及び一般式（Ｃｃ−２）中、「＊」は、一般式（８）中のＲ^Ｃ１に結合する結合手を示す。なお、一般式（Ｃｃ−１）及び（Ｃｃ−２）で表される基は置換基を有していてもよい。）In the general formula (8), ^examples of R ^Cc include groups represented by the following general formula (Cc-1) or (Cc-2).

(In General Formula (Cc-1), n _C1 represents an integer of 0 to 2. In General Formula (Cc-2), n _{C2 to} n _C5 each independently represents an integer of 0 to 2. In the general formula (Cc-1) and the general formula (Cc-2), “*” represents a bond bonded to R ^C1 in the general formula (8). The group represented by Cc-2) may have a substituent.)

(I) Repeat unit (3):
Among the groups represented by R ¹⁰ in the general formula (6), examples of the linear or branched alkyl group having 3 to 4 carbon atoms include an n-propyl group, an i-propyl group, and an n- Examples include butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group and the like.

  Examples of the monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms include cyclohexane such as norbornane, tricyclodecane, tetracyclododecane, adamantane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, and cyclooctane. Groups composed of alicyclic rings derived from alkanes and the like; groups composed of these alicyclic rings are, for example, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2- Examples include a group substituted with a linear or branched alkyl group having 3 to 4 carbon atoms such as a methylpropyl group, a 1-methylpropyl group, and a t-butyl group, or a cycloalkyl group.

Furthermore, examples of the divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms formed by bonding any two R ¹⁰ to each other include, for example, norbornane, tricyclodecane, tetracyclododecane, adamantane, cyclo A group consisting of an alicyclic ring derived from pentane, cyclohexane, etc .; a group consisting of these alicyclic rings is, for example, a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, 2 Examples thereof include a group substituted with a linear or branched alkyl group having 3 to 4 carbon atoms such as a methylpropyl group, a 1-methylpropyl group, and a t-butyl group, or a cycloalkyl group.

In the general formula (6), preferred examples of the group represented by —C (R ¹⁰ ) ₃ include t-butyl group, 1-n- (1,1-dimethyl) propyl group, 1- (1,1 A group having no alicyclic ring such as -diethyl) propyl group; 1- (1-methyl) cyclopentyl group, 1- (1-ethyl) cyclopentyl group, 1- (1-methyl) cyclohexyl group, 1- (1 -Ethyl) cyclohexyl group, 1- (1-methyl-1- (2-norbornyl)) ethyl group, 1- (1-methyl-1- (2-tetracyclodecanyl)) ethyl group, 1- (1- Methyl-1- (1-adamantyl)) ethyl group, 2- (2-methyl) norbornyl group, 2- (2-ethyl) norbornyl group, 2- (2-n-propyl) norbornyl group, 2- (2- Methyl) tetracyclododecanyl group, 2- (2-ethyl) A group having an alicyclic ring such as a tracyclododecanyl group, 2- (2-methyl) adamantyl group, 2- (2-ethyl) adamantyl group; a group having these alicyclic rings is, for example, a methyl group Linear or branched having 3 to 10 carbon atoms such as ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group, etc. Examples include groups substituted with a cycloalkyl group having 4 to 20 carbon atoms such as an alkyl group, a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group.

  Among these, (meth) acrylic acid 2-methyladamantan-2-yl ester, (meth) acrylic acid 2-ethyladamantan-2-yl ester, (meth) acrylic acid-2-methylbicyclo [2.2.1]. ] Hept-2-yl ester, (meth) acrylic acid-2-ethylbicyclo [2.2.1] hept-2-yl ester, (meth) acrylic acid 1- (bicyclo [2.2.1] hept- 2-yl) -1-methylethyl ester, (meth) acrylic acid 1- (adamantan-1-yl) -1-methylethyl ester, (meth) acrylic acid 1-methyl-1-cyclopentyl ester, (meth) acrylic Acid 1-ethyl-1-cyclopentyl ester, (meth) acrylic acid 1-methyl-1-cyclohexyl ester, (meth) acrylic acid 1-ethyl-1 Cyclohexyl ester are particularly preferred.

  A polymer (A) may contain only 1 type of repeating units (3), and may contain 2 or more types. The content ratio of the repeating unit (3) is preferably 20 to 90 mol%, more preferably 20 to 80 mol%, still more preferably with respect to 100 mol% of the total repeating units contained in the polymer (A). 20-70 mol%. When the content ratio of the repeating unit (3) is within this range, it is particularly effective from the viewpoint of coexistence of control of solubility in the developer after coating and resistance to exposure when forming the second resist pattern. is there.

(Ii) Repeating unit (4):
Among the groups represented by R ¹¹ in general formula (7-1), examples of the optionally substituted alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, and i. -Propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group and the like.

  Monomers that give a repeating unit represented by the general formula (8) are described in, for example, Tetrahedron Letters, Vol. 27, no. 32 p. 3741 (1986), Organic Letters, Vol. 4, no. 15 p. 2561 (2002), etc., and can be synthesized by a conventionally known method.

Particularly preferred examples of the repeating unit represented by the general formula (8) include repeating units represented by the general formulas (8-1) to (8-22). Incidentally, ^{R 1} in the general formula (8-1) to (8-22) has the same definition as ^{R 1} in the general formula (8).

  A polymer (A) may contain only 1 type of repeating units (4), and may contain 2 or more types. The content ratio of the repeating unit (4) is usually 80 mol% or less, preferably 20 to 80 mol%, more preferably 30 to 100 mol% with respect to a total of 100 mol% of the repeating units contained in the polymer (A). 70 mol%. When the content ratio of the repeating unit (4) is within this range, it is particularly effective from the viewpoint of achieving both control of solubility in the developer and resistance to exposure when forming the second resist pattern.

(Iii) Other repeating units:
Further, the polymer (A) may contain one or more kinds of repeating units other than the repeating unit (3) and the repeating unit (4) (hereinafter also referred to as “other repeating units”).

  Examples of other repeating units include a repeating unit represented by the general formula (9) (hereinafter also referred to as “repeating unit (5)”) and a repeating unit represented by the general formula (10) (hereinafter referred to as “repeating unit”). Unit (6) ").

（一般式（９）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す。Ｚは、単結合又は炭素数１〜３の２価の有機基を示す。Ｗは、炭素数７〜２０の置換されていてもよい多環型脂環式炭化水素基を示す。但し、多環型脂環式炭化水素基が置換基を有する場合、置換基としてはメチル基、エチル基、炭素数３〜１０の直鎖状若しくは分岐状のアルキル基、炭素数４〜２０のシクロアルキル基、ヒドロキシル基、シアノ基、炭素数１〜１０のヒドロキシアルキル基、カルボキシル基、又はオキソ基である。）

(In General Formula (9), R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group. Z represents a single bond or a divalent organic group having 1 to 3 carbon atoms. W represents the number of carbon atoms. 7 to 20 optionally substituted polycyclic alicyclic hydrocarbon group, provided that when the polycyclic alicyclic hydrocarbon group has a substituent, the substituent includes a methyl group, an ethyl group, A linear or branched alkyl group having 3 to 10 carbon atoms, a cycloalkyl group having 4 to 20 carbon atoms, a hydroxyl group, a cyano group, a hydroxyalkyl group having 1 to 10 carbon atoms, a carboxyl group, or an oxo group. .)

（一般式（１０）中、Ｒ^１４は、水素原子、メチル基、トリフルオロメチル基又はヒドロキシメチル基を示す。Ｒ^１５は、２価の有機基を示す。）

(In the general formula (10), R ¹⁴ represents a hydrogen atom, a methyl group, a trifluoromethyl group or a hydroxymethyl group. R ¹⁵ represents a divalent organic group.)

In the general formula (9), the optionally substituted polycyclic alicyclic hydrocarbon group having 7 to 20 carbon atoms represented by W is, for example, bicyclo [2.2.1] represented by the following formula. ] Heptane (9a), bicyclo [2.2.2] octane (9b), tricyclo [5.2.1.0 ^2,6 ] decane (9c), tetracyclo [6.2.1.1 ^3,6 . Hydrocarbon groups derived from cycloalkanes such as 0 ^2,7 ] dodecane (9d) and tricyclo [3.3.1.1 ^3,7 ] decane (9e).

  When the hydrocarbon group derived from cycloalkane has a substituent, examples of the substituent include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, and 2-methyl. C4-C20 cycloalkyl such as linear or branched alkyl group having 3 to 10 carbon atoms such as propyl group, 1-methylpropyl group and t-butyl group, cyclopentyl group, cyclohexyl group and cyclooctyl group There are groups. In addition, a substituent is not limited to these alkyl groups, A hydroxyl group, a cyano group, a C1-C10 hydroxyalkyl group, a carboxy group, and an oxo group may be sufficient.

In the general formula (10), the divalent organic group represented by R ¹⁵ is preferably a divalent hydrocarbon group, and more preferably a chain or cyclic divalent hydrocarbon group. It may be an alkylene glycol group, an alkylene ester group, or the like. Specific examples of the divalent organic group include alkanes such as a methylene group, an ethylene group, an icosalen group, a 1-methyl-1,3-propylene group, a 2-methyl-1,3-propylene group, and a 2-propylidene group. Diyl group;

  Monocyclic hydrocarbon ring groups such as cycloalkylene groups having 3 to 10 carbon atoms such as 1,3-cyclobutylene group and 1,3-cyclopentylene group; 1,4-norbornylene group, 1,5-adamantylene Examples thereof include a bridged cyclic hydrocarbon ring group such as a 2-4 cyclic hydrocarbon ring group having 4 to 30 carbon atoms such as a group. Among these, a hydrocarbon group containing a 2,5-norbornylene group, a 1,2-ethylene group, and a propylene group are preferable.

When R ¹⁵ contains a divalent aliphatic cyclic hydrocarbon ring group, a bistrifluoromethyl-hydroxy-methyl group (—C (CF ₃ ) ₂ OH) and a divalent aliphatic cyclic carbonization group It is preferable to arrange an alkanediyl group having 1 to 4 carbon atoms as a spacer between the hydrogen group.

(2) Polymer (B):
The polymer (B) includes a repeating unit having a crosslinking group and a repeating unit having a fluorine atom. The first radiation-sensitive composition contains the oil-repellent polymer (B), so that when the resist film is formed, the distribution tends to be higher on the resist film surface. Therefore, at the time of immersion exposure, it is possible to suppress the acid generator (C), the acid diffusion control agent, and the like in the resist film from being eluted into an immersion liquid such as water. Further, the receding contact angle between the resist film and the immersion liquid is increased due to the water-repellent characteristics of the polymer (B). Therefore, water droplets derived from the immersion liquid are unlikely to remain on the resist film, and the occurrence of defects such as watermarks due to the immersion liquid can be suppressed even when scanning exposure is performed at high speed. Furthermore, the first resist pattern can be insolubilized in the second radiation-sensitive composition by heating or irradiation.

  Especially, it is preferable that a polymer (B) further contains the repeating unit which has an acid labile group. This is because the polymer (B) has a property of being dissolved in an alkali developer by the action of an acid.

  Content of a polymer (B) is 1-80 mass parts normally with respect to 100 mass parts of polymers (A), Preferably it is 2-50 mass parts, More preferably, it is 5-25 mass parts. It is. When the content is in this range, it is possible to have sufficient resistance to the second radiation-sensitive composition, and it is possible to suppress poor resolution when forming the first resist pattern.

(I) Repeating unit having a crosslinking group:
The repeating unit having a crosslinking group is preferably the repeating unit (1). The cross-linking group is preferably a thermosetting reactive group.

Among the groups represented by the general formula (2) or (3), examples of the linear or branched alkyl group having 3 to 10 carbon atoms represented by R ⁶ include an n-propyl group, i -Propyl group, 2-methylpropyl group, 1-methylpropyl group, n-butyl group, t-butyl group and the like.

Specific examples of the repeating unit represented by the general formula (1-1) include repeating units represented by the following general formulas (1-1-a) to (1-1-h). . In general formulas (1-1-a) to (1-1-h), R ¹ represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

Specific examples of the repeating unit represented by the general formula (1-2) include the repeating units represented by the following general formulas (1-2a) to (1-2-d). . In general formulas (1-2-a) to (1-2-d), R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group.

  Among these, repeating units represented by (1-1-a), (1-1-e), and (1-2-a) are more preferable.

  The ratio of the repeating unit (1) contained in the polymer (B) is preferably 1 to 30 mol% with respect to 100 mol% in total of the repeating units contained in the polymer (B), and is 1 to 25 mol%. More preferably, it is more preferably 5 to 15 mol%. When the ratio of the repeating unit (1) is within this range, the alkali developing portion is less likely to swell with the alkali developing solution, and the solubility in the alkali developing solution is maintained, thereby suppressing line width variation and dimensional accuracy reduction. be able to.

(Ii) Repeating unit having a fluorine atom:
The repeating unit having a fluorine atom is preferably a repeating unit represented by the repeating unit (2) or the general formula (f-4).

Among the groups represented by R ⁷ in the general formula (4), the linear or branched, saturated or unsaturated divalent hydrocarbon group having 1 to 20 carbon atoms is, for example, a methyl group , Ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group, pentyl group, isopentyl group, neopentyl group, hexyl group, heptyl group , A divalent hydrocarbon group derived from a linear or branched alkyl group having 3 to 20 carbon atoms such as an octyl group, a nonyl group, and a decyl group.

In addition, examples of the cyclic saturated or unsaturated divalent hydrocarbon group include groups derived from alicyclic hydrocarbons and aromatic hydrocarbons having 3 to 20 carbon atoms. Examples of the alicyclic hydrocarbon include cyclobutane, cyclopentane, cyclohexane, bicyclo [2.2.1] heptane, bicyclo [2.2.2] octane, and tricyclo [5.2.1.0 ^2,6 ]. Decane, tricyclo [3.3.1.1 ^3,7 ] decane, tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecane and other cycloalkanes. Examples of the aromatic hydrocarbon include benzene and naphthalene.

Note that the hydrocarbon group in R ⁷ represents at least one hydrogen atom in the above-described unsubstituted hydrocarbon group as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a 2-methyl group. C3-C12 linear or branched alkyl group such as propyl group, 1-methylpropyl group, t-butyl group, cycloalkyl group, hydroxy group, cyano group, C1-C10 hydroxyalkyl group , A carboxy group, a group substituted by one or more of oxygen atoms and the like.

Specific examples of R ⁷ in the general formula (4) include groups represented by the following structures (a1) to (a27). In addition, “*” in the structures (a1) to (a27) represents a binding site.

In particular, R ⁷ in the general formula (4) is preferably a methylene group, an ethylene group, a 1-methylethylene group, a 2-methylethylene group, a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or the like.

  In the general formula (4), examples of the methylene group substituted with a fluorine atom represented by X or a linear or branched fluoroalkanediyl group having 2 to 20 carbon atoms include the following formula (X-1): There are groups represented by structures such as ~ (X-8).

  In particular, the repeating unit represented by the general formula (4) is preferably a repeating unit derived from the compounds represented by the formulas (4-1) to (4-6).

In the general formula (5), among the groups represented by R ^9, as a methyl group, an ethyl group, or a linear or branched alkyl group having 3 to 6 carbon atoms having at least one fluorine atom, For example, methyl group, ethyl group, 1-propyl group, 2-propyl group, 1-butyl group, 2-butyl group, 2- (2-methylpropyl) group, 1-pentyl group, 2-pentyl group, 3 -Pentyl group, 1- (2-methylbutyl) group, 1- (3-methylbutyl) group, 2- (2-methylbutyl) group, 2- (3-methylbutyl) group, neopentyl group, 1-hexyl group, 2- Hexyl group, 3-hexyl group, 1- (2-methylpentyl) group, 1- (3-methylpentyl) group, 1- (4-methylpentyl) group, 2- (2-methylpentyl) group, 2- (3-methylpentyl) group, 2- (4-methylpe Nthyl) group, 3- (2-methylpentyl) group, 3- (3-methylpentyl) group, and the like include partially fluorinated or perfluoroalkyl groups of linear or branched alkyl groups. Specific examples include groups represented by the following formulas (Y-1) to (Y-8).

  Examples of the C 4-20 monovalent alicyclic hydrocarbon group having at least one fluorine atom include a cyclopentyl group, a cyclopentylmethyl group, a 1- (1-cyclopentylethyl) group, 1- (2-cyclopentylethyl) group, cyclohexyl group, cyclohexylmethyl group, 1- (1-cyclohexylethyl) group, 1- (2-cyclohexylethyl group), cycloheptyl group, cycloheptylmethyl group, 1- (1-cyclo Heptylethyl) group, 1- (2-cycloheptylethyl) group, 2-norbornyl group and other alicyclic alkyl groups such as partially fluorinated or perfluoroalkyl groups.

  Preferred monomers that give the repeating unit (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) Crylic 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.

（一般式（ｆ−４）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す。Ｒ^ｋ４は、（ｍ＋１）価の連結基を示す。Ｘ^ｆ４は、フッ素原子を有する２価の連結基を示す。Ｒ^ｊ４は、水素原子又は１価の有機基を示す。ｍは１〜３の整数である。なお、ｍが２又は３の場合、複数のＲ^ｊ４はそれぞれ独立して水素原子又は１価の有機基を示す。）The polymer (B) may have a repeating unit (f) represented by the following general formula (f-4) (hereinafter also referred to as “repeating unit (f)”).

(In General Formula (f-4), R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group. R ^k4 represents a (m + 1) -valent linking group. X ^f4 represents a fluorine atom 2 R ^j4 represents a hydrogen atom or a monovalent organic group, m is an integer of 1 to 3. When m is 2 or 3, a plurality of R ^j4 are independently selected. Represents a hydrogen atom or a monovalent organic group.)

In the general formula (f-4), the (m + 1) -valent linking group represented by R ^k4 is an (m + 1) -valent hydrocarbon having 1 to 10 carbon atoms which may have an ether group or an ester group. Group, more preferably an (m + 1) -valent hydrocarbon group having 1 to 8 carbon atoms which may have an ether group or an ester group, and particularly preferably an ether group or an ester group. It is a good (m + 1) -valent hydrocarbon group having 1 to 5 carbon atoms. Moreover, as a bivalent coupling group which has a fluorine atom represented as ^Xf4 , it is preferable that it is a C1-C20 bivalent chain hydrocarbon group which has a fluorine atom. Specific examples include groups represented by the formulas (X-1) to (X-8). Among these, X ^f4 is preferably a group represented by the formula (X-1) or (X-2).

^Examples of the monovalent organic group represented by R ^j4 include an acid labile group or a hydrocarbon group having 1 to 30 carbon atoms which may have a substituent. R ^j4 is preferably a hydrogen atom, a t-butoxycarbonyl group, or an alkoxy-substituted methyl group.

In general formula (f-4), m is an integer of 1 to 3. Accordingly, 1 to 3 R ^j4 are introduced into the repeating unit (f-4). When m is 2 or 3, a plurality of X ^f4 may be bonded to the same carbon atom among the carbon atoms constituting R ^k4 or may be bonded to different carbon atoms.

Specific examples of the repeating unit (f-4) include repeating units represented by the following general formulas (f4-1) to (f4-4). In general formulas (f4-1) to (f4-4), R ¹ represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

  The polymer (B) may contain only one type of repeating unit (2), or may contain two or more types. The content ratio of the repeating unit (2) is preferably 1 to 60 mol%, more preferably 5 to 50 mol%, based on 100 mol% of the total repeating units contained in the polymer (B). More preferably, it is -45 mol%. When the content ratio of the repeating unit (2) is within this range, it is possible to maintain a sufficient receding contact angle with respect to the immersion liquid and to sufficiently develop with an alkaline developer.

(Iii) Repeating unit having an acid labile group:
The repeating unit having an acid labile group is not particularly limited, and includes the repeating unit (3) described in “(1) Polymer (A)”. In addition, a polymer (B) may contain only 1 type of repeating units (3), and may contain 2 or more types. The content ratio of the repeating unit (3) is preferably 10 to 90 mol%, more preferably 10 to 80 mol%, still more preferably with respect to 100 mol% of the total repeating units contained in the polymer (B). 20-70 mol%. When the content ratio of the repeating unit (3) is within this range, it is possible to maintain a sufficient receding contact angle with respect to the immersion liquid and to sufficiently develop with an alkaline developer.

(Iv) Other repeating units:
The polymer (B) may contain a repeating unit other than the above repeating units (1) to (3) (hereinafter also referred to as “other repeating units”). As other repeating units, the repeating unit (7) represented by the repeating unit (4), the repeating unit (6) and the following general formula (11) described in “(1) Polymer (A)” ( Hereinafter, it is also referred to as “repeating unit (7)”.

  The content ratio of the repeating unit (4) is preferably 5 to 70 mol%, more preferably 5 to 65 mol%, based on 100 mol% of the total repeating units contained in the polymer (B). More preferably, it is -60 mol%, and it is especially preferable that it is 10-20 mol%. When the content ratio of the repeating unit (4) is within this range, developability as a resist and process margin such as exposure amount and focus can be maintained.

  The content ratio of the repeating unit (6) is preferably 30 mol% or less and more preferably 25 mol% or less with respect to 100 mol% of the total repeating units contained in the polymer (B). It can suppress that the top loss of a resist pattern arises because the content rate of a repeating unit (6) exists in this range. In addition, since the repeating unit (6) is an arbitrary component, it may not be included in the polymer (B).

（一般式（１１）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す。Ｘは、単結合又は２価の連結基を示す。Ｒ^Ｃは、置換されていてもよい炭素数３〜３０の（ｎ＋１）価の脂環式炭化水素基を示す。Ｒｆは、１〜１０個のフッ素原子を有する炭素数１〜３０の１価の鎖状炭化水素基、又は１〜１０個のフッ素原子を有する炭素数３〜３０の１価の脂環式炭化水素基を示す。ｎは１〜３の整数である。なお、ｎが２又は３の場合、複数のＲｆはそれぞれ独立して１〜１０個のフッ素原子を有する炭素数１〜３０の１価の鎖状炭化水素基、又は１〜１０個のフッ素原子を有する炭素数３〜３０の１価の脂環式炭化水素基を示す。）

(In the general formula (11), R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group. X represents a single bond or a divalent linking group. R ^C represents an optionally substituted carbon. And an (n + 1) -valent alicyclic hydrocarbon group having a number of 3 to 30. Rf is a monovalent chain hydrocarbon group having 1 to 30 carbon atoms and having 1 to 10 carbon atoms, or 1 to 10 1 represents a monovalent alicyclic hydrocarbon group having 3 to 30 carbon atoms having one fluorine atom, n is an integer of 1 to 3. When n is 2 or 3, a plurality of Rf are independent of each other. A monovalent chain hydrocarbon group having 1 to 30 carbon atoms having 1 to 10 fluorine atoms, or a monovalent alicyclic hydrocarbon group having 3 to 30 carbon atoms having 1 to 10 fluorine atoms. Group.)

（一般式（１１−１）中、Ｒ^１、Ｘ、Ｒｆ及びｎの定義は一般式（１１）と同じである。Ｒ^Ｓは、−Ｒ^Ｐ１、−Ｒ^Ｐ２−Ｏ−Ｒ^Ｐ１、−Ｒ^Ｐ２−ＣＯ−Ｒ^Ｐ１、−Ｒ^Ｐ２−ＣＯ−ＯＲ^Ｐ１、−Ｒ^Ｐ２−Ｏ−ＣＯ−Ｒ^Ｐ１、−Ｒ^Ｐ２−ＯＨ、−Ｒ^Ｐ２−ＣＮ、又は−Ｒ^Ｐ２−ＣＯＯＨを示す（Ｒ^Ｐ１は、炭素数１〜１０の１価の鎖状飽和炭化水素基、炭素数３〜２０の１価の脂肪族環状飽和炭化水素基又は炭素数６〜３０の１価の芳香族炭化水素基を示す。なお、これらの基を構成する水素原子の一部又は全部がフッ素原子で置換されていてもよい。Ｒ^Ｐ２は、単結合、炭素数１〜１０の２価の鎖状飽和炭化水素基、炭素数３〜２０の２価の脂肪族環状飽和炭化水素基、又は炭素数６〜３０の２価の芳香族炭化水素基を示す。なお、これらの基を構成する水素原子の一部又は全部がフッ素原子で置換されていてもよい。）。ｎ_Ｓは０〜３の整数である。）The repeating unit (7) is preferably a repeating unit represented by the following general formula (11-1).

(In the general formula ^(11-1), the definition of R 1, X, Rf and n are the same as in the formula (11) .R ^{S is, -R P1, -R P2 -O-} R P1, -R ^{P 2} —CO—R ^{P 1} , —R ^P2 —CO—OR ^{P 1} , —R ^P2 —O—CO—R ^P1 , —R ^P2 —OH, —R ^P2 —CN, or —R ^P2 —COOH (R ^P1 Is a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms, a monovalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms. In addition, some or all of hydrogen atoms constituting these groups may be substituted with fluorine atoms, R ^P2 is a single bond, a divalent chain saturated hydrocarbon group having 1 to 10 carbon atoms. , A divalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms . It should be noted that some or all of the hydrogen atoms constituting these groups may be substituted with a fluorine atom.). N _S is an integer of 0-3.)

  Specific examples of the repeating unit represented by the general formula (11-1) include a repeating unit represented by the following formula (11-1-1).

  The content ratio of the repeating unit (7) is preferably 90 mol% or less, and more preferably 75 mol% or less with respect to 100 mol% of the total repeating units contained in the polymer (B). It is preferable for the content ratio of the repeating unit (7) to be within this range since the shape of the resist pattern becomes good. In addition, since a repeating unit (7) is an arbitrary component, it does not need to be contained in a polymer (B).

(Method for preparing each polymer)
Each polymer, for example, using a polymerizable unsaturated monomer that gives each repeating unit described above, a radical polymerization initiator such as hydroperoxides, dialkyl peroxides, diacyl peroxides, azo compounds, If necessary, it can be prepared by polymerization in an appropriate solvent in the presence of a chain transfer agent.

  Examples of the solvent used for the polymerization include alkanes such as n-pentane and n-hexane; cycloalkanes such as cyclohexane, cycloheptane and cyclooctane; aromatic hydrocarbons such as benzene and toluene; chlorobutane and bromo Halogenated hydrocarbons such as hexane; saturated carboxylic acid esters such as ethyl acetate and n-butyl acetate; ketones such as acetone and 2-butanone; ethers such as tetrahydrofuran and dimethoxyethane. In addition, these solvents may be used individually by 1 type, and 2 or more types may be mixed and used for them.

(Physical properties of polymer)
The weight average molecular weight (hereinafter also referred to as “Mw”) in terms of polystyrene by gel permeation chromatography (GPC) of each polymer is not particularly limited. However, it is preferable that it is 1000-100,000, respectively, it is more preferable that it is 1000-30000, and it is still more preferable that it is 1000-20000. When Mw is within this range, both the heat resistance of the first resist layer and the developability of the alkali developing portion can be achieved.

  In addition, the ratio (Mw / Mn) between the Mw of each polymer and the polystyrene-equivalent number average molecular weight (hereinafter also referred to as “Mn”) by gel permeation chromatography (GPC) of each polymer is usually: It is 1-5, and it is preferable that it is 1-3.

  In addition, each polymer may contain a low molecular weight component derived from a monomer used for preparation. The content of this low molecular weight component is preferably 0.1% by mass or less, more preferably 0.07% by mass or less, and still more preferably 100% by mass (in terms of solid content) of each polymer. It is 0.05 mass% or less. When the content ratio of the low molecular weight component is 0.1% by mass or less, it is possible to reduce the amount of the eluate in the immersion liquid such as water that is in contact during the immersion exposure. In addition, foreign matters are less likely to occur in the resist during resist storage, and coating unevenness is less likely to occur during resist application, so that the occurrence of defects during resist pattern formation can be sufficiently suppressed. It is particularly preferred that each polymer does not contain a low molecular weight component.

  In the present specification, the “low molecular weight component” means a component having an Mw of 500 or less, and specifically includes a monomer, a dimer, a trimer, and an oligomer. The low molecular weight component can be removed by, for example, chemical purification methods such as washing with water and liquid-liquid extraction, or a combination of these chemical purification methods and physical purification methods such as ultrafiltration and centrifugation. The analysis can be performed by high performance liquid chromatography (HPLC).

  Furthermore, it is preferable that each polymer has few impurities such as halogen and metal. This is because by reducing the impurities, it is possible to further improve the etching resistance of the first resist layer to be formed, the prevention of deterioration of the electrical characteristics of the device due to the impurities derived from the resist pattern, and the like.

  Examples of the purification method for each polymer include chemical purification methods such as washing with water and liquid-liquid extraction, and combinations of these chemical purification methods with physical purification methods such as ultrafiltration and centrifugation.

(3) Acid generator (C):
An acid generator (C) means what generate | occur | produces an acid by exposure. When the first radiation-sensitive composition contains the acid generator (C), an acid labile group present in the polymer by the action of the acid generated by exposure, specifically, the repeating unit (3) The acid labile group possessed by can be dissociated (the protecting group is eliminated). As a result, the alkali developing part becomes readily soluble in the alkali developer, and a resist pattern can be formed. In addition, as an acid generator (C), what contains the compound (henceforth "acid generator (1)") represented by General formula (12) is preferable.

  The content of the acid generator (C) is usually 0.1 to 20 parts by mass with respect to 100 parts by mass of the polymer (A) from the viewpoint of ensuring the sensitivity and developability as a resist, preferably It is 0.5-10 mass parts, More preferably, it is 5-10 mass parts. When the content is within this range, sufficient transparency to radiation can be obtained without lowering the sensitivity and developability, and a rectangular resist pattern can be obtained.

(I) Acid generator (1):
The acid generator (1) is a compound represented by the general formula (12).

（一般式（１２）中、Ｒ^１６は、水素原子、フッ素原子、水酸基、メチル基、エチル基、炭素数３〜１０の直鎖状若しくは分岐状のアルキル基、メトキシ基、エトキシ基、炭素数３〜１０の直鎖状若しくは分岐状のアルコキシ基、メトキシカルボニル基、エトキシカルボニル基、又は炭素数４〜１１の直鎖状若しくは分岐状のアルコキシカルボニル基を示す。また、Ｒ^１７は、メチル基、エチル基、炭素数３〜１０の直鎖状若しくは分岐状のアルキル基、メトキシ基、エトキシ基、炭素数３〜１０の直鎖状若しくは分岐状のアルコキシ基、又は、メチルスルホニル基、エチルスルホニル基、炭素数３〜１０の直鎖状、分岐状若しくは環状のアルキルスルホニル基を示す。更に、Ｒ^１８は、相互に独立に、メチル基、エチル基、炭素数３〜１０の直鎖状若しくは分岐状のアルキル基、フェニル基、又はナフチル基を示す。但し、二つのＲ^１８が相互に結合してイオウカチオンを含む炭素数２〜１０の２価の基を形成していてもよい。なお、フェニル基、ナフチル基、及び炭素数２〜１０の２価の基は置換基を有していても良い。ｋは、０〜２の整数を示し、ｒは、０〜８の整数（好ましくは０〜２の整数）を示す。Ｘ⁻は、一般式（１２−１）〜（１２−４）で表されるアニオンを示す。）

(In the general formula (12), R ¹⁶ is a hydrogen atom, a fluorine atom, a hydroxyl group, a methyl group, an ethyl group, a linear or branched alkyl group having 3 to 10 carbon atoms, a methoxy group, an ethoxy group, or a carbon number. A linear or branched alkoxy group having 3 to 10 carbon atoms, a methoxycarbonyl group, an ethoxycarbonyl group, or a linear or branched alkoxycarbonyl group having 4 to 11 carbon atoms, and R ¹⁷ is a methyl group. , An ethyl group, a linear or branched alkyl group having 3 to 10 carbon atoms, a methoxy group, an ethoxy group, a linear or branched alkoxy group having 3 to 10 carbon atoms, or a methylsulfonyl group, ethylsulfonyl group, a straight, branched or cyclic alkylsulfonyl group having 3 to 10 carbon atoms. further, R ¹⁸ are mutually independently, a methyl group, an ethyl group, a carbon number 3-1 Linear or branched alkyl group, a phenyl group, or a naphthyl group. However, the two R ¹⁸ are to form a divalent group having 2 to 10 carbon atoms containing sulfur cations bind to each other The phenyl group, naphthyl group, and divalent group having 2 to 10 carbon atoms may have a substituent, k is an integer of 0 to 2, and r is 0 to 0. .X showing the 8 integer (preferably an integer from 0 to 2) ^- represents an anion represented by the general formula (12-1) to (12-4)).

（一般式（１２−１）及び（１２−２）中、Ｒ^１９は、フッ素原子又は置換されていても良い炭素数１〜１２の炭化水素基を示す。一般式（１２−１）中、ｑは、１〜１０の整数を示す。一般式（１２−３）及び（１２−４）中、Ｒ^２０は、相互に独立に、フッ素原子で置換された、メチル基、エチル基、炭素数３〜１０の直鎖状又は分岐状のアルキル基を示す。但し、二つのＲ^２０が相互に結合して、フッ素原子で置換された炭素数２〜１０の２価の有機基を形成していてもよい。なお、フッ素原子で置換された炭素数２〜１０の２価の有機基はフッ素原子以外の置換基を有しても良い。）

(In General Formulas (12-1) and (12-2), R ¹⁹ represents a fluorine atom or an optionally substituted hydrocarbon group having 1 to 12 carbon atoms. In General Formula (12-1), q represents an integer of 1 to 10. In the general formulas (12-3) and (12-4), R ²⁰ is, independently of each other, a methyl group, an ethyl group, or a carbon number substituted with a fluorine atom. Represents a linear or branched alkyl group having 3 to 10 provided that two R ²⁰ are bonded to each other to form a divalent organic group having 2 to 10 carbon atoms substituted with a fluorine atom. In addition, the C2-C10 divalent organic group substituted with a fluorine atom may have a substituent other than a fluorine atom.

  In addition, an acid generator (C) may contain 1 type of acid generators (1) individually, and may contain 2 or more types.

  Further, the acid generator (C) may contain a radiation sensitive acid generator other than the acid generator (1) (hereinafter also referred to as “acid generator (2)”).

(Ii) Acid generator (2):
Examples of the acid generator (2) include onium salt compounds, halogen-containing compounds, diazoketone compounds, sulfone compounds, and sulfonic acid compounds. In addition, an acid generator (C) may contain 1 type of acid generators (2) individually, and may contain 2 or more types.

  Moreover, when using an acid generator (2), the use ratio is 80 mass% or less normally with respect to 100 mass% of acid generators (C), Preferably it is 60 mass% or less.

(4) Solvent (D):
Examples of the solvent (D) include linear or branched ketones such as 2-butanone and 2-pentanone; cyclic ketones such as cyclopentanone, 3-methylcyclopentanone and cyclohexanone; propylene glycol monomethyl Propylene glycol monoalkyl ether acetates such as ether acetate and propylene glycol monoethyl ether acetate; 2-hydroxypropionate alkyls such as methyl 2-hydroxypropionate and ethyl 2-hydroxypropionate; methyl 3-methoxypropionate, 3 -Alkyl 3-alkoxypropionates such as ethyl methoxypropionate and methyl 3-ethoxypropionate,

  alcohols such as n-propyl alcohol and i-propyl alcohol; ethylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether; diethylene glycol dialkyl ethers such as diethylene glycol dimethyl ether and diethylene glycol diethyl ether; ethylene glycol monomethyl ether Acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono-n-propyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, toluene, xylene, 2-hydroxy-2-methyl Ethyl propionate, Ethoxy acetate , Ethyl acetate, n-propyl acetate, n-butyl acetate, methyl acetoacetate, ethyl acetoacetate, methyl pyruvate, ethyl pyruvate, N-methylpyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide benzyl alcohol Benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, γ-butyrolactone, ethylene carbonate, propylene carbonate and the like.

  Among these, linear or branched ketones, cyclic ketones, propylene glycol monoalkyl ether acetates, alkyl 2-hydroxypropionate, alkyl 3-alkoxypropionate, γ-butyrolactone and the like are preferable.

  The 1st radiation sensitive composition may contain the solvent (D) individually by 1 type, and may contain 2 or more types.

  The amount of the solvent (D) used is such that the total solid concentration of the first radiation-sensitive composition is usually 1 to 50% by mass, preferably 1 to 25% by mass.

(5) Additive:
The first radiation-sensitive composition may contain various additives such as an acid diffusion controller, an alicyclic additive, a surfactant, and a sensitizer as necessary.

(I) Acid diffusion control agent:
The acid diffusion control agent is a component having an action of controlling a diffusion phenomenon of an acid generated from the acid generator (C) by exposure in the first resist layer and suppressing an undesirable chemical reaction in a non-exposed region. By containing such an acid diffusion controller, the pattern shape of the first radiation-sensitive composition is improved. In addition, the resolution as a resist is further improved, and it is possible to suppress changes in the line width of the resist pattern due to fluctuations in the holding time (PED) from exposure to post-exposure heat treatment, and an extremely excellent process stability. Things are obtained.

  Examples of the acid diffusion controller include mono (cyclo) alkylamines, di (cyclo) alkylamines, tri (cyclo) alkylamines, substituted alkylanilines or derivatives thereof, ethylenediamine, N, N, N ′, N Amine compounds such as' -tetramethylethylenediamine and tetramethylenediamine; Nt-butoxycarbonyldi-n-octylamine, Nt-butoxycarbonyldi-n-nonylamine, Nt-butoxycarbonylpyrrolidine, formamide, N Amide group-containing compounds such as methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide, benzamide, pyrrolidone, N-methylpyrrolidone; urea, methylurea, 1,1 -Dimethylu Urea compounds such as A, imidazoles; pyridines; other piperazines, pyrazine, pyrazole, pyridazine, quinoxaline, purine, pyrrolidine, and nitrogen-containing heterocyclic compounds such as piperidine, there is a photodegradable base, and the like.

  As an example of the photodegradable base, there is an onium salt compound which is decomposed by exposure and deactivates acid diffusion controllability. Specific examples of such an onium salt compound include a sulfonium salt compound represented by the general formula (13) and an iodonium salt compound represented by the general formula (14).

（一般式（１３）中のＲ^２１〜Ｒ^２３、及び一般式（１４）中のＲ^２４〜Ｒ^２５は、相互に独立に、水素原子、アルキル基、アルコキシ基、ヒドロキシ基、又はハロゲン原子を示す。また、一般式（１３）及び（１４）中、Ｚ⁻は、ＯＨ⁻、Ｒ^２６−ＣＯＯ⁻、Ｒ^２６−ＳＯ_３ ⁻（但し、Ｒ^２６は、アルキル基、アリール基、又はアルカリール基を示す）、又は一般式（１５）で表されるアニオンを示す。）

(R ^{21 to} R ²³ in the general formula (13) and R ^{24 to} R ²⁵ in the general formula (14) are each independently a hydrogen atom, an alkyl group, an alkoxy group, a hydroxy group, or a halogen atom. In the general formulas (13) and (14), Z ⁻ represents OH ⁻ , R ²⁶ —COO ⁻ , R ²⁶ —SO ₃ ^— (wherein R ²⁶ represents an alkyl group, an aryl group, or an alkaryl group). Or an anion represented by the general formula (15).)

（一般式（１５）中、Ｒ^２７は、メチル基、エチル基、炭素数３〜１２の直鎖状若しくは分岐状のアルキル基、メトキシ基、エトキシ基、又は炭素数３〜１２の直鎖状若しくは分岐状のアルコキシ基を示す。但し、メチル基、エチル基、炭素数３〜１２の直鎖状若しくは分岐状のアルキル基はフッ素原子で置換されていてもよい。ｎは、０〜２の整数を示す。）

(In the general formula (15), R ²⁷ is a methyl group, an ethyl group, a linear or branched alkyl group having 3 to 12 carbon atoms, a methoxy group, an ethoxy group, or a linear chain having 3 to 12 carbon atoms. Or a branched alkoxy group, provided that a methyl group, an ethyl group, or a linear or branched alkyl group having 3 to 12 carbon atoms may be substituted with a fluorine atom, and n is 0 to 2 Indicates an integer.)

  In addition, these acid diffusion control agents may be used individually by 1 type, and 2 or more types may be mixed and used for them.

  The content of the acid diffusion controller is preferably 0.001 to 15 parts by mass, more preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of the polymer (A). It is more preferable that it is 05-5 mass parts, and it is especially preferable that it is 0.5-1.5 mass parts. When the content is within this range, the pattern shape and dimensional fidelity as a resist can be maintained without reducing the sensitivity as a resist.

(Ii) Alicyclic additives:
An alicyclic additive is a component that exhibits an action of further improving dry etching resistance, pattern shape, adhesion to a substrate, and the like.

Examples of alicyclic additives include polar group-substituted adamantanes; deoxycholic acid esters; lithocholic acid esters; alkyl carboxylic acid esters; 3- (2-hydroxy-2,2-bis (trifluoromethyl) Ethyl) tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecane and the like. In addition, you may use these alicyclic additives individually by 1 type or in mixture of 2 or more types.

(Iii) Surfactant:
A surfactant is a component that exhibits an effect of improving coating properties, striation, developability, and the like.

  Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyethylene glycol dilaurate, polyethylene glycol In addition to nonionic surfactants such as distearate, KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, no. 95 (above, manufactured by Kyoeisha Chemical Co., Ltd.), F-top EF301, EF303, EF352 (above, manufactured by Tochem Products), Megafax F171, F173 (above, manufactured by Dainippon Ink and Chemicals), Florard FC430, FC431 (above, manufactured by Sumitomo 3M), Asahi Guard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 ( As mentioned above, manufactured by Asahi Glass Co., Ltd.). In addition, these surfactants may be used individually by 1 type, and 2 or more types may be mixed and used for them.

(Iv) Sensitizer:
The sensitizer absorbs radiation energy and transmits the energy to the acid generator (C), thereby increasing the amount of acid produced. The sensitizer of the first radiation-sensitive composition It has the effect of improving the apparent sensitivity.

  Examples of the sensitizer include carbazoles, acetophenones, benzophenones, naphthalenes, phenols, biacetyl, eosin, rose bengal, pyrenes, anthracenes, phenothiazines, and the like. In addition, these sensitizers may be used individually by 1 type, and 2 or more types may be mixed and used for them.

(V) Other additives:
The first radiation-sensitive composition may contain additives other than the additives described above (hereinafter also referred to as “other additives”). Examples of other additives include a low-molecular alkali solubility controller having an acid-dissociable protecting group, an antihalation agent, a storage stabilizer, and an antifoaming agent. In addition, by including a dye or a pigment, the latent image of the exposed portion can be visualized, and the influence of halation during exposure can be reduced. Furthermore, the adhesiveness with a board | substrate can be improved by containing an adhesion assistant.

  The first radiation-sensitive composition can be prepared as a coating solution by dissolving each component in the solvent (D) and then filtering with a filter having a pore size of about 0.2 μm, and can be applied onto the substrate. it can.

2. Second radiation sensitive composition:
The second radiation-sensitive composition used when forming the second resist layer is a polymer (a) that becomes alkali-soluble by the action of an acid (hereinafter also referred to as “polymer (a)”), And a solvent (b).

(1) Polymer (a):
The polymer (a) is not particularly limited as long as it is an alkali-insoluble or hardly alkali-soluble polymer that becomes alkali-soluble by the action of an acid. Specifically, there is one containing the repeating unit (3).

  Further, the polymer (a) can contain a repeating unit represented by the general formula (16) (hereinafter also referred to as a repeating unit (8)).

（一般式（１６）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す。Ｒ^２８は、単結合、メチレン基、炭素数２〜６の直鎖状若しくは分岐状のアルカンジイル基、又は炭素数４〜１２の単環若しくは多環の脂環式のアルカンジイル基を示す。）

(In the general formula (16), R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group. R ²⁸ represents a single bond, a methylene group or a linear or branched alkanediyl having 2 to 6 carbon atoms. Group, or a monocyclic or polycyclic alicyclic alkanediyl group having 4 to 12 carbon atoms.)

Preferable examples of the monomer giving the repeating unit (8) include (meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-3-propyl) ester, (meth) Acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-butyl) ester, (meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-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) acrylic acid 3- ( 8- (1 ', 1', 1'-trifluoro-2'-trifluoromethyl-2'-hydroxy) propyl) tetracyclo ^[6.2.1.1 3,6 ^{.0 2,7]} dodecyl) ester Etc.

  In addition, a polymer (a) may contain only 1 type of repeating units (8), and may contain 2 or more types.

  The polymer (a) may contain other repeating units in addition to the repeating unit (3) and the repeating unit (8).

(Ratio of each repeating unit contained in polymer (a))
The ratio of the repeating unit (3) contained in the polymer (a) is preferably 10 to 70 mol% with respect to 100 mol% in total of the repeating units contained in the polymer (a), and is preferably 10 to 60 mol%. More preferably, it is more preferably 20 to 60 mol%. When the ratio of the repeating unit (3) is within this range, both the resolution and developability of the alkali developing part can be achieved.

  The ratio of the repeating unit (8) contained in the polymer (a) is preferably 0 to 90 mol% with respect to 100 mol% in total of the repeating units contained in the polymer (a), and is 30 to 80 mol%. More preferably, it is more preferably 40 to 80 mol%. When the ratio of the repeating unit (3) is within this range, the resolution of the alkali developing portion can be maintained.

  The proportion of other repeating units contained in the polymer (a) is preferably 50 mol% or less, preferably 40 mol% or less, with respect to 100 mol% in total of the repeating units contained in the polymer (a). More preferred. In addition, since another repeating unit is an arbitrary component, it does not need to be contained in a polymer (B).

  In addition, a 2nd radiation sensitive composition may contain 1 type of polymers (a) individually, and may contain 2 or more types.

(Method for preparing polymer (a))
The polymer (a) can be prepared in the same manner as the polymer (A) or the polymer (B), for example, using a polymerizable unsaturated monomer that gives each repeating unit.

(Physical property value of polymer (a))
The Mw of the polymer (a) is not particularly limited. However, it is preferably 1000-100000, more preferably 1000-30000, and still more preferably 1000-20000. When the Mw of the polymer (a) is within this range, both the heat resistance of the second resist layer and the developability of the alkali developing part can be achieved. Moreover, the ratio (Mw / Mn) of Mw and Mn of the polymer (a) is usually 1 to 5, preferably 1 to 3.

  In addition, the polymer (a) may contain a low molecular weight component derived from a monomer used for preparation. The content ratio of the low molecular weight component is preferably 0.1% by mass or less, more preferably 0.07% by mass or less, with respect to 100% by mass (in terms of solid content) of the polymer (a). More preferably, it is 0.05 mass% or less. When the content ratio of the low molecular weight component is 0.1% by mass or less, it is possible to reduce the amount of the eluate in the immersion liquid such as water that has been contacted during the immersion exposure. Furthermore, foreign matters are not generated in the resist during resist storage, and coating unevenness does not occur during resist application, and the occurrence of defects during resist pattern formation can be sufficiently suppressed. The polymer (a) particularly preferably does not contain a low molecular weight component.

  Moreover, it is preferable that a polymer (a) is a thing with few impurities, such as a halogen and a metal. Thus, by reducing impurities, the sensitivity, resolution, process stability, pattern shape, etc. of the second resist layer can be further improved.

  Examples of the method for purifying the polymer (a) include the same methods as described above.

(2) Solvent (b):
The solvent (b) is not particularly limited. However, it is preferable to dissolve the polymer (a) but not the first resist pattern. Examples include linear or branched ketones, cyclic ketones, alkylene glycol monoalkyl ether acetates, alkyl 2-hydroxypropionate, alkyl 3-alkoxypropionate, and γ-butyrolactone. it can. Among these, propylene glycol monomethyl ether acetate and cyclohexanone are preferable.

  The amount of the solvent (b) used is such that the total solid concentration of the second radiation-sensitive composition is usually 1 to 50% by mass, preferably 1 to 25% by mass.

(3) Radiation sensitive acid generator:
The second radiation-sensitive composition usually contains a radiation-sensitive acid generator. As a radiation sensitive acid generator, the same thing as the acid generator (C) in the above-mentioned 1st radiation sensitive composition can be used. The acid generator (C) contained in the first radiation-sensitive composition and the radiation-sensitive acid generator contained in the second radiation-sensitive composition may be the same or different. May be.

  The content of the radiation-sensitive acid generator is usually 0.1 to 20 parts by mass with respect to 100 parts by mass of the polymer (a), preferably from the viewpoint of ensuring the sensitivity and developability as a resist. It is 0.5-10 mass parts, More preferably, it is 5-10 mass parts. When the content is within this range, transparency to radiation can be maintained without lowering sensitivity and developability, and a rectangular second resist pattern can be obtained.

(4) Additive:
The second radiation sensitive composition may contain an additive. In addition, as this additive, the same thing as various additives, such as the acid diffusion control agent mentioned above in the 1st radiation sensitive composition, can be said.

  When the second radiation-sensitive composition contains an acid diffusion controller as an additive, the content is preferably 0.001 to 15 parts by mass with respect to 100 parts by mass of the polymer (a). , 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, and particularly preferably 0.5 to 1.5 parts by mass. When the content is in this range, the pattern shape and dimensional fidelity as a resist can be maintained without reducing the sensitivity as a resist.

  The second radiation-sensitive composition can be prepared as a coating solution by dissolving each component in the solvent (b) and then filtering with a filter having a pore size of about 0.2 μm, and can be applied on the substrate. it can.

  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.

  [Weight average molecular weight (Mw) and number average molecular weight (Mn)]: GPC columns (2 G2000HXL, 1 G3000HXL, 1 G4000HXL) manufactured by Tosoh Corporation, flow rate: 1.0 mL / min, elution solvent: tetrahydrofuran, column temperature: Monodispersed polystyrene was measured as a standard by gel permeation chromatography (GPC) under analysis conditions of 40 ° C.

^[13 C-NMR Analysis: The ¹³ C-NMR analysis of the polymer was measured using a JEOL Ltd. "JNM-EX270".

  [Measurement of receding contact angle (°)]: A radiation-sensitive composition was spin-coated on a Si substrate with an SOD coating film forming apparatus (trade name “CLEAN TRACK ACT8”, manufactured by Tokyo Electron Ltd.), and 100 Pre-baking (PB) was performed at 60 ° C. for 60 seconds to form a film with a film thickness of 100 nm, and then promptly using a contact angle meter (trade name “DSA-10”, manufactured by KRUS) at room temperature of 23 ° C. and humidity The receding contact angle was measured according to the following procedure under an environment of 45% normal pressure.

  First, the wafer stage position of the contact angle meter is adjusted, and the substrate 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 substrate. Thereafter, water is discharged from the needle to form a 25 μL water droplet on the substrate. The needle is once withdrawn from the water droplet, and the needle is pulled down to the initial position again 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 between the liquid surface and the substrate 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 as the receding contact angle.

  [DP Pattern Evaluation]: An evaluation substrate C described later after forming the second resist pattern was observed using a scanning electron microscope (manufactured by Hitachi Keiki Co., Ltd., CG-4000). When the first resist pattern is lost or there is an insoluble material at the bottom of the opening, it is evaluated as “bad” and resolved without top loss scum, and both the first resist pattern and the second resist pattern are The case where it was formed was evaluated as “good”. In Examples 34 to 36, a contact hole pattern was formed by forming a line pattern of 48 nm lines / 96 nm pitch (48 nm 1 L / 1 S) so as to be orthogonal to the first resist pattern. The case where the contact hole pattern was resolved and formed without being buried to the bottom was evaluated as “good”.

  [Line width variation]: The line width variation of the resist pattern on the substrate C was observed using a scanning electron microscope (trade name “CG-4000”, manufactured by Hitachi Keiki Co., Ltd.). The line width of each of the arbitrary five line portions of the resist pattern line portion of the evaluation substrate C was measured at 20 arbitrary points. The average value of the line widths (total 100 points) of any five line portions was defined as the average line width. The difference between the average line width after forming the first resist pattern and the average line width after double patterning (forming the second resist pattern) was taken as the fluctuation value of the line width variation. A measured line width variation value of less than 4 nm was evaluated as “◎ (excellent)”, 4-7 nm was evaluated as “◯ (good)”, and a value exceeding 7 nm was evaluated as “× (defect). ".

  Hereinafter, a method for preparing the polymers (A) and (B) will be described. The monomers [compounds (M-1) to (M-22)] used for the preparation of the polymers (A) and (B) are shown below.

(Preparation Example 1: Preparation of polymer (A-1))
First, compound (M-14) 15 mol%, compound (M-13) 35 mol%, compound (M-8) 50 mol%, and polymerization initiator (dimethyl-2,2′-azobisisobutyrate) as monomers A monomer solution in which (MAIB)) was dissolved in 100 g of methyl ethyl ketone was prepared. The total amount of monomers at the time of preparation was adjusted to 50 g. In addition, mol% of each monomer represents mol% with respect to the total amount of the monomer, and the use ratio of the polymerization initiator was 2 mol% with respect to the total amount of the monomer and the polymerization initiator.

On the other hand, 50 g of methyl ethyl ketone was added to a 500 mL three-necked flask equipped with a thermometer and a dropping funnel, and purged with nitrogen for 30 minutes. Then, it heated so that it might become 80 degreeC, stirring the inside of a flask with a magnetic stirrer. Subsequently, the prepared monomer solution was dripped in the flask over 3 hours using the dropping funnel. After completion of dropping, the mixture was aged for 3 hours and then cooled to 30 ° C. or lower to obtain a polymer solution. Thereafter, the polymer solution was added to 1000 g of methanol and mixed. Then suction filtration was performed. Thereafter, the powder was recovered, re-introduced into 200 g of methanol, washed and filtered. This cleaning was performed again, and the recovered powder was dried under reduced pressure at 60 ° C. Let the obtained polymer be a polymer (A-1). This polymer (A-1) has Mw of 10,000 and Mw / Mn of 1.5. As a result of ¹³ C-NMR analysis, the content of each repeating unit derived from each monomer (mol%) ) Was a copolymer of (M-14) / (M-13) / (M-8) = 14.6 / 35.9 / 49.5.

(Preparation Example 9: Preparation of polymer (B-1))
First, as a monomer, the compound (M-2) 55 mol%, the compound (M-19) 5 mol%, the compound (M-8) 20 mol%, the compound (M-20) 20 mol%, and a polymerization initiator (dimethyl-2) , 2′-azobisisobutyrate (MAIB)) in 100 g of methyl ethyl ketone was prepared. The total amount of monomers at the time of preparation was adjusted to 50 g. In addition, mol% of each monomer represents mol% with respect to the total amount of monomers, and the use ratio of the polymerization initiator was 8 mol% with respect to the total amount of the monomer and the polymerization initiator.

On the other hand, 50 g of methyl ethyl ketone was added to a 500 mL three-necked flask equipped with a thermometer and a dropping funnel, and purged with nitrogen for 30 minutes. Then, it heated so that it might become 80 degreeC, stirring the inside of a flask with a magnetic stirrer. Subsequently, the prepared monomer solution was dripped in the flask over 3 hours using the dropping funnel. After completion of dropping, the mixture was aged for 3 hours and then cooled to 30 ° C. or lower to obtain a polymer solution. Thereafter, the polymer solution was added to 1000 g of methanol and mixed. Then suction filtration was performed. Thereafter, the powder was recovered, re-introduced into 200 g of methanol, washed and filtered. This cleaning was performed again, and the recovered powder was dried under reduced pressure at 60 ° C. Let the obtained polymer be a polymer (B-1). This polymer (B-1) has an Mw of 5500 and an Mw / Mn of 1.5. As a result of ¹³ C-NMR analysis, the content of each repeating unit derived from each monomer (mol%) ) Was a copolymer of (M-2) / (M-19) / (M-8) / (M-20) = 54.5 / 5.5 / 19.5 / 20.5.

(Preparation Examples 2-27: Polymers (A-2) to (A-10), Polymers (B-2) to (B-13), and Polymers (F-1) to (F-4) Preparation)
The polymers (A-2) to (A-10) were prepared in the same manner as in Preparation Example 1 except that the types and amounts of the compounds (monomers) shown in Table 1 were used. (B-2) to (B-13) and the polymers (F-1) to (F-4) were prepared in the same manner as in Preparation Example 9. Incidentally, in Table 2, the polymer (A-2) ~ (A -10), 13 of the polymer (B-2) ~ (B -13), and the polymer (F-1) ~ (F -4) The content, Mw, and Mw / Mn of each repeating unit derived from each monomer by C-NMR are described.

(Example 1: Preparation of first radiation-sensitive composition)
90 parts of polymer (A-1) as polymer (A), 10 parts of polymer (B-1) as polymer (B), acid generator (C-1) (triphenyl) as acid generator (C) 7.5 parts of sulfonium nonafluoro-n-butanesulfonate), 0.94 parts of acid diffusion inhibitor (E-1) (Nt-butoxycarbonylpyrrolidine) as nitrogen-containing compound (E), and as solvent (D) 1287 parts of solvent (D-1) (propylene glycol monomethyl ether acetate) and 551 parts of solvent (D-2) (cyclohexanone) were added and the components were mixed to obtain a homogeneous solution. Then, the coating liquid (1) which consists of a 1st radiation sensitive composition was prepared by filtering using a membrane filter with a hole diameter of 200 nm.

(Examples 2 to 22 and Comparative Examples 1 to 5: Preparation of first radiation-sensitive composition)
Each coating solution was prepared in the same manner as in Example 1 except that the formulation described in Table 3 was used. In addition, the usage-amount of each component makes a total amount of a polymer (A), a polymer (B), and a polymer (F) 100 parts.

  Acid generator (C-1): triphenylsulfonium nonafluoro-n-butanesulfonate

Solvent (D-1): Propylene glycol monomethyl ether acetate Solvent (D-2): Cyclohexanone

  Nitrogen-containing compound (E-1): Nt-butoxycarbonylpyrrolidine

(Preparation of second radiation-sensitive composition)
100 parts of polymer (B-9) represented by formula (B-9) as polymer (a), 7.0 parts of triphenylsulfonium nonafluoro-n-butanesulfonate as a radiation sensitive acid generator, acid diffusion 2.64 parts of compound (E-2) as an inhibitor (E) and 2014 parts of propylene glycol monomethyl ether acetate as a solvent (b) were added, and each component was mixed to obtain a uniform solution. Then, the coating liquid (28) which consists of a 2nd radiation sensitive composition was prepared by filtering using a membrane filter with a hole diameter of 200 nm.

(Example 23: Formation of resist pattern)
A 12-inch silicon wafer was spin-coated with a lower antireflection film (trade name “ARC66”, manufactured by Brewer Science) using a coater / developer (trade name “Lithius Pro-i”, manufactured by Tokyo Electron). Thereafter, PB (205 ° C., 60 seconds) was performed to form a coating film having a thickness of 77 nm. Using the SOD coating film-forming apparatus (trade name “CLEAN TRACK ACT12”, manufactured by Tokyo Electron Ltd.), the coating liquid (1) (first radiation-sensitive composition) prepared in Example 1 was spin-coated, After PB (130 ° C., 60 seconds), a first resist layer having a thickness of 90 nm was formed by cooling (23 ° C., 30 seconds).

  Next, ArF immersion exposure apparatus (trade name “S610C”, manufactured by NIKON) is used, and pure water is arranged on the surface of the first resist layer under the optical conditions of NA: 1.30 and Dipole. Then, exposure was performed using a line pattern mask. After PEB (125 ° C., 60 seconds) on the coater / developer hot plate and cooling (23 ° C., 30 seconds), a 2.38% tetramethylammonium hydroxide aqueous solution was added with a GP nozzle of the developing cup. Paddle development (10 seconds) was performed as a developer, and rinsed with ultrapure water. The substrate A for evaluation on which the first resist pattern of 26 nm line / 104 nm pitch was formed was obtained by spin-drying by shaking off at 2000 rpm for 15 seconds.

  The first resist pattern of the obtained evaluation substrate A was subjected to PDB (200 ° C., 60 seconds) on the hot plate of the SOD coating film forming apparatus to obtain an evaluation substrate B.

  The substrate B for evaluation is spin-coated with the coating liquid (28) (second radiation sensitive composition) using the SOD coating film forming apparatus, PB (100 ° C., 60 seconds), and then cooled ( And a second resist layer having a thickness of 70 nm was formed. Using the ArF immersion exposure apparatus, exposure was performed using a line pattern mask in a state where pure water was disposed on the surface of the second resist layer under the optical conditions of NA: 1.30 and Dipole. . After PEB (105 ° C., 60 seconds) was cooled on the coater / developer hot plate and cooled (23 ° C., 30 seconds), a 2.38% tetramethylammonium hydroxide aqueous solution was added with a GP nozzle of the developing cup. Paddle development (10 seconds) was performed as a developer, and rinsed with ultrapure water. By spin-drying by shaking off at 2000 rpm for 15 seconds, an evaluation substrate C on which a second resist pattern having a 26 nm line / 104 nm pitch was formed was obtained. The evaluation of the DP pattern of the evaluation substrate C was “good”, and the evaluation of the line width variation was “◎ (excellent)”.

(Examples 24-44)
Each evaluation substrate C was obtained in the same manner as in Example 23 except that the conditions described in Table 4 were used. The evaluation results of the obtained evaluation substrates C are also shown in Table 4. For Examples 34 to 36, the first resist pattern was exposed by placing pure water on the surface of the first resist layer using a mask for forming 48 nm lines / 96 nm pitch (48 nm 1 L / 1S). A contact hole pattern was formed by immersion exposure using a mask for forming a 48 nm line / 96 nm pitch (48 nm 1 L / 1 S) so as to be orthogonal to the surface.

  However, in Example 25, instead of PDB, UV irradiation (172 nm, 10 seconds) was applied to the first resist pattern of the obtained evaluation substrate A with a lamp (made by USHIO INC.) Containing Xe gas. Then, an evaluation substrate C was obtained.

(Comparative Examples 6 to 10)
Each evaluation substrate C was obtained in the same manner as in Example 23 except that the conditions described in Table 5 were used. The evaluation results of the obtained evaluation substrates C are also shown in Table 5.

  As can be seen from Table 4 and Table 5, according to the resist pattern forming method using the radiation-sensitive composition of the present invention, the DP pattern is good, and a pattern exceeding the wavelength limit is obtained without performing large line width fluctuations. Can be formed. On the other hand, when only the polymer (A) is used alone, or when the polymer (F-1) not containing a repeating unit having a crosslinking group and a repeating unit having a fluorine atom is used, the DP pattern is evaluated. Was “defective”, the line width variation was “× (defective)”, and the receding contact angle was 55 °. (Comparative Examples 6 and 7). Further, when the polymer (F-2) containing no fluorine atom-containing repeating unit is used, the evaluation of the DP pattern is “good”, and the line width variation is “「 (excellent) ”. The receding contact angle was 57 °, and water droplets remained on the line pattern after exposure (Comparative Example 8). Thus, when water droplets remain on the line pattern, a problem occurs in patterning. Furthermore, when the polymer (F-3) or (F-4) containing an excess of a repeating unit having a crosslinking group or a repeating unit having a fluorine atom is used, the evaluation of the DP pattern is “bad”. The line width variation was “x (defect)” (Comparative Examples 9 and 10).

  According to the resist pattern forming method using the radiation-sensitive composition of the present invention, a pattern exceeding the wavelength limit can be formed favorably and economically. Therefore, it can be used very suitably in the field of microfabrication represented by the manufacture of integrated circuit elements that are expected to become increasingly finer in the future.

1: substrate, 2: first resist layer, 3: immersion liquid, 4: mask, 5, 35: alkali developing portion, 6: lens, 12, 22: first resist pattern, 12a, 22a: first 12b, 22b: first space portion, 15: contact hole pattern, 32: second resist layer, 42: second resist pattern, 42a: second line portion, 42b: second space portion.

Claims (15)

A step (1) of forming a first resist pattern on a substrate using the first radiation-sensitive composition;
A step (2) of insolubilizing the first resist pattern with respect to the second radiation-sensitive composition;
Step (3) of forming a second resist pattern on the substrate on which the first resist pattern is formed using the second radiation-sensitive composition (Step 3). Used in 1)
(A) a polymer containing a repeating unit having an acid labile group;
(B) a polymer containing a repeating unit having a crosslinking group and a repeating unit having a fluorine atom;
(C) a radiation sensitive acid generator;
(D) a solvent ,
A radiation-sensitive composition, wherein the crosslinking group is a crosslinking group for insolubilizing the first resist pattern with respect to a second radiation-sensitive composition.   The radiation sensitive composition of Claim 1 which contains 1-80 mass parts of said polymers (B) with respect to 100 mass parts of said polymers (A).   The radiation-sensitive composition according to claim 1, wherein the crosslinking group is a thermosetting reactive group. The polymer (B) is
The repeating unit (1) represented by at least any one of the repeating unit represented by the following general formula (1-1) and the repeating unit represented by the following general formula (1-2). The radiation sensitive composition as described in any one of Claims.

(In the general formulas (1-1) and (1-2), R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group. In the general formula (1-1), R ² represents a methylene group. And R ³ represents a group represented by the following general formula (2) or (3), wherein R ⁴ represents a methylene group or a carbon number. And represents an alkanediyl group of 2 to 6. R ⁵ represents a hydrogen atom, a methyl group or an ethyl group, and n represents 0 or 1.

(In the general formulas (2) and (3), a plurality of R ⁶ are each independently a hydrogen atom, a methyl group, an ethyl group, or a linear or branched alkyl group having 3 to 10 carbon atoms. Show.) The polymer (B) is
The repeating unit (2) represented by at least any one of the repeating unit represented by the following general formula (4) and the repeating unit represented by the following general formula (5). The radiation-sensitive composition as described in 1.

(In the general formula (4), R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group. R ⁷ is a single bond or a linear, branched or cyclic saturated group having 1 to 20 carbon atoms. Alternatively, it represents an unsaturated divalent hydrocarbon group, X represents a methylene group substituted with a fluorine atom or a linear or branched fluoroalkanediyl group having 2 to 20 carbon atoms, R ⁸ represents hydrogen It represents an atom or a monovalent organic group.)

(In the general formula (5), R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group. A represents a single bond, an ether bond, a thioether bond, a carbonyl group, an ester group, an amide group, or a sulfonamide group. R ⁹ represents a divalent organic group having a urethane group, R ⁹ is a methyl group, an ethyl group, a linear or branched alkyl group having 3 to 6 carbon atoms, having at least one fluorine atom, or A monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms is shown.)   The radiation sensitive composition according to any one of claims 1 to 5, wherein the polymer (B) further comprises a repeating unit having an acid labile group. The radiation-sensitive composition according to claim 6, wherein the repeating unit having an acid labile group is a repeating unit (3) represented by the following general formula (6).

(In the general formula (6), R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group. R ^{10 s} are each independently a methyl group, an ethyl group, or a straight chain having 3 to 4 carbon atoms. or branched alkyl group, or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms. the number of carbon atoms with one carbon atom to two R ¹⁰ are attached respectively bonded to each other A divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, and the remaining R ¹⁰ is a methyl group, an ethyl group, a linear or branched alkyl group having 3 to 4 carbon atoms, or a carbon number of 4 to 20 monovalent alicyclic hydrocarbon groups may be shown.)   The radiation sensitive composition according to any one of claims 2 to 7, wherein the polymer (A) does not contain a repeating unit having a crosslinking group. The radiation-sensitive composition according to claim 4 , wherein the content ratio of the repeating unit (1) is 1 to 30 mol% with respect to a total of 100 mol% of repeating units contained in the polymer (B). The radiation-sensitive composition according to claim 5 , wherein a content ratio of the repeating unit (2) is 1 to 70 mol% with respect to a total of 100 mol% of repeating units contained in the polymer (B). Using the radiation-sensitive composition according to any one of claims 1 to 10, a step (1) of forming a first resist pattern on a substrate;
A step (2) of insolubilizing the first resist pattern with respect to the second radiation-sensitive composition;
A step (3) of forming a second resist pattern on the substrate on which the first resist pattern is formed using the second radiation-sensitive composition. The first resist pattern has a line portion and a space portion,
The second resist pattern has a line portion and a space portion,
The resist pattern forming method according to claim 11, wherein the second resist pattern is formed so that the line portion of the first resist pattern and the line portion of the second resist pattern intersect each other. . The first resist pattern has a line portion and a space portion,
The second resist pattern has a line portion and a space portion,
The resist pattern forming method according to claim 11, wherein the second resist pattern is formed so that the line portion of the first resist pattern and the line portion of the second resist pattern are parallel to each other.   In the step (1), the radiation-sensitive composition is applied onto the substrate to form a first resist layer, and after heating, the first resist layer is used as the outermost surface, and an exposure process is performed. It is a process of forming said 1st resist pattern, The resist pattern formation method as described in any one of Claims 11-13.   In the step (3), the second radiation-sensitive composition is applied onto the substrate on which the first resist pattern is formed to form a second resist layer, and after heating, The resist pattern forming method according to any one of claims 11 to 14, which is a step of forming the second resist pattern by exposing the resist layer to the outermost surface and performing an exposure process.

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