JP4872691B2 - Resist pattern forming method - Google Patents

Description

  The present invention relates to a resist pattern forming method. More specifically, the present invention relates to a resist pattern forming method using a positive radiation sensitive resin composition that is suitably used for immersion exposure in which a resist film is exposed through an immersion exposure liquid such as water.

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. However, in the conventional lithography process, near-ultraviolet rays such as i-rays are generally used as radiation, and it is said that fine processing at a subquarter micron level is extremely difficult with this near-ultraviolet rays. Therefore, in order to enable microfabrication at a level of 0.10 μm or less, use of radiation having a shorter wavelength is being studied. Examples of such short-wavelength radiation include an emission line spectrum of a mercury lamp, far-ultraviolet rays typified by an excimer laser, an X-ray, an electron beam, and the like. Among these, a KrF excimer laser (wavelength 248 nm) is particularly preferable. ) Or ArF excimer laser (wavelength 193 nm) has been attracting attention.
As a resist suitable for irradiation with such an excimer laser, a component having an acid-dissociable functional group and a component that generates acid upon irradiation with radiation (hereinafter referred to as “exposure”) (hereinafter referred to as “acid generator”). )) And a resist utilizing the chemical amplification effect (hereinafter referred to as “chemically amplified resist”) have been proposed. As the chemically amplified resist, for example, a resist containing a resin having a tert-butyl ester group of carboxylic acid or a tert-butyl carbonate group of phenol and an acid generator has been proposed. In this resist, the tert-butyl ester group or tert-butyl carbonate group present in the resin is dissociated by the action of an acid generated by exposure, and the resin has an acidic group composed of a carboxyl group or a phenolic hydroxyl group. As a result, the phenomenon that the exposed region of the resist film becomes readily soluble in an alkali developer is utilized.

  In such a lithography process, further fine pattern formation (for example, a fine resist pattern having a line width of about 45 nm) will be required in the future. In order to achieve such fine pattern formation of less than 45 nm, it is conceivable to shorten the light source wavelength of the exposure apparatus and increase the numerical aperture (NA) of the lens as described above. However, a new expensive exposure apparatus is required to shorten the light source wavelength. Further, when the lens has a high NA, the resolution and the depth of focus are in a trade-off relationship. Therefore, there is a problem that the depth of focus decreases even if the resolution is increased.

  Recently, a liquid immersion lithography (liquid immersion lithography) method has been reported as a lithography technique that can solve such problems. In this method, at the time of exposure, a liquid high refractive index medium (immersion exposure liquid) such as pure water or a fluorine-based inert liquid having a predetermined thickness on at least the resist film between the lens and the resist film on the substrate. Is to intervene. In this method, a light source having the same exposure wavelength can be used by replacing the exposure optical path space, which has conventionally been an inert gas such as air or nitrogen, with a liquid having a higher refractive index (n), such as pure water. Similar to the case of using a light source with a shorter wavelength or the case of using a high NA lens, high resolution is achieved and there is no reduction in the depth of focus. If such immersion exposure is used, it is possible to realize the formation of a resist pattern that is low in cost, excellent in high resolution, and excellent in depth of focus, using a lens mounted on an existing apparatus. It has attracted a great deal of attention and is being put to practical use.

  However, it is said that the extension of the exposure technique is limited to 45 nmhp, and technical development for the 32 nmhp generation that requires further fine processing is being carried out. In recent years, along with the demand for higher complexity and higher density of such devices, half cycle of sparse line pattern or isolated trench pattern such as double patterning or double exposure as seen in Non-Patent Document 1 and Non-Patent Document 2. A technique for patterning 32 nm LS by shifting superposition has been proposed. In addition, in contact hole processing, in order to compensate for a lack of process margin of a sparse pattern, a process of processing a different pitch by closing a part of a dense pattern with the second layer processing is also proposed (see Patent Documents 1 to 3). .)

As one of the proposed examples, after forming a 32 nm line with a pitch of 1: 3, a hard mask such as SiO ₂ is processed by etching, and at a position shifted by a half cycle from the first resist pattern, Similarly, a 32 nm line having a pitch of 1: 3 is formed, and HM is processed again by etching. As a result, there is an example in which a 32 nm line having a pitch of 1: 1 is finally formed (Non-Patent Document 2).

JP 2006-171118 A JP 2006-139218 A JP 2006-145788 A SPIE 2006 61531K 3rd International Symposium on Immersion Lithography PO-11

  However, although there are proposals for several processes, no concrete material has been proposed yet.

  The present invention has been made in view of the above circumstances, and in patterning by double exposure, resist pattern formation capable of forming a second layer resist pattern without mixing with the first layer resist pattern It aims to provide a method.

〔一般式（１）において、Ｒ^１は水素原子、メチル基又はトリフルオロメチル基を示し、Ｒ^２は単結合、メチレン、炭素数２〜６の直鎖状或いは分岐状のアルキレン基、又は、炭素数４〜１２の脂環式のアルキレン基を示す。〕 Means for achieving the above object are as follows.
[1] using (i) the positive-tone radiation-sensitive resin composition for the first resist layer forming a first resist layer formed on a substrate, irradiating the principal area region where said first resist layer The first resist pattern is formed using a step of forming a first resist pattern by developing after exposure and ( ii ) a positive radiation sensitive resin composition for forming a second resist layer. after been formed a second resist layer on the substrate, by exposing to radiation to said second resist layer and a main area region at said first resist pattern, to the optical the first resist pattern converting mechanism to inactivate, and forming a pattern latent image portion on the second resist layer, by developing (iii), the space portion of the first resist pattern, a second resist pattern A resist pattern forming method comprising the steps of forming a
The positive-type radiation-sensitive resin composition for forming the second resist layer contains a resin (A) that becomes alkali-soluble by the action of an acid, and a solvent (B), and the solvent (B) The method of forming a resist pattern, wherein the first resist pattern is not dissolved.
[ 2 ] The resist pattern forming method according to [1], wherein the solvent (B) is an alcohol solvent.
[ 3 ] The alcohol solvent is 1-butyl alcohol, 2-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, tert-amyl alcohol, neopentyl alcohol. 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, 2,3-dimethyl-2- Butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-diethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2- Methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol Or at least one of 4-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol and cyclohexanol [ 2 ] The resist pattern forming method according to [ 2 ].
[ 4 ] The resist pattern forming method according to any one of [1] to [ 3 ], wherein the resin (A) contains a repeating unit represented by the following general formula (1).

[In General Formula (1), R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group, and R ² represents a single bond, methylene, a linear or branched alkylene group having 2 to 6 carbon atoms, or An alicyclic alkylene group having 4 to 12 carbon atoms is shown. ]

  According to the resist pattern forming method of the present invention, in patterning by double exposure, the resist layer formed in the first layer is mixed with an alcohol solvent that does not dissolve, that is, the resist layer formed in the first layer. By using a resin composition containing a difficult alcohol solvent, it is possible to form and pattern a second resist layer without mixing with the patterned first resist. Therefore, it can be used very suitably for manufacturing semiconductor devices that will be further miniaturized in the future.

Hereinafter, the present invention will be described in detail.
[1] Resist pattern forming method
The resist pattern forming method of the reference invention includes the following steps (1) to (4).
Step (1): A first resist layer is formed on a substrate using a positive radiation-sensitive resin composition for forming a first resist layer (hereinafter also referred to as “resin composition for forming a first resist layer”). formed was exposed to light by irradiating the essential region at the first resist layer by developing, step step (2) forming a first resist pattern; the first resist pattern to light Step of inactivation Step (3): Using the positive radiation-sensitive resin composition for forming the second resist layer (hereinafter also referred to as “resin composition for forming the second resist layer”), the first the second resist layer is formed on a substrate on which the resist pattern has been formed, step step (4) to be exposed by irradiating the essential region at the second resist layer; by developing, the first resist pattern In the space part, the second The step of forming the strike pattern

Both the “resin composition for forming a first resist layer” and the “resin composition for forming a second resist layer” used in the pattern forming method of the reference invention are both produced by the action of an acid generated from an acid generator by exposure. The acid dissociable group in the resin component is dissociated to form a carboxyl group. As a result, the solubility of the exposed portion of the resist in the alkaline developer is increased, and the exposed portion is dissolved and removed by the alkaline developer. This resist pattern can be obtained. Details of components and the like contained in these resin compositions will be described later.

In the step (1), the resin composition for forming the first resist layer is applied onto a substrate such as a silicon wafer or a wafer coated with aluminum by an appropriate application means such as spin coating, cast coating, or roll coating. To form a first resist layer. Although the thickness of this 1st resist layer is not specifically limited, Usually, it is 10-1000 nm, Preferably it is 10-500 nm.
Moreover, after apply | coating the resin composition for 1st resist layer formation, you may volatilize the solvent in a coating film by prebaking (PB) as needed. Although the prebaking heating conditions are appropriately selected depending on the composition of the resin composition, it is generally about 30 to 200 ° C, preferably 50 to 150 ° C.

Then, in the step (1), the main region at a first resist layer formed, through a mask having a predetermined pattern, irradiated by exposing, the pattern latent image portion (exposed to the first resist layer, an alkali Insoluble part) is formed.
The exposure method is not particularly limited, but it is preferable to use an immersion exposure method. When using the immersion exposure method, the radiation is in the main region at a first resist layer, through a liquid for liquid immersion lithography and such as water or a fluorine-based inert liquid through a mask having a predetermined pattern illuminated Is done.
The radiation used for the exposure is appropriately selected from visible rays, ultraviolet rays, far ultraviolet rays, X-rays, charged particle beams, etc., depending on the type of acid generator contained in the resin composition. Far ultraviolet rays typified by laser (wavelength 193 nm) or KrF excimer laser (wavelength 248 nm) are preferable, and ArF excimer laser (wavelength 193 nm) is particularly preferable.
Moreover, exposure conditions, such as exposure amount, are suitably selected according to the compounding composition of the resin composition for 1st resist layer formation, the kind of additive, etc.
Furthermore, in the reference invention, it is preferable to perform heat treatment (PEB) after exposure. By this PEB, the dissociation reaction of the acid dissociable group in the resin component can smoothly proceed. The heating conditions for PEB are appropriately selected depending on the composition of the resin composition, but are usually 30 to 200 ° C, preferably 50 to 170 ° C.

Further, in step (1), the exposed first resist layer is developed to expose the pattern latent image portion and form a positive first resist pattern.
Examples of the developer used for this development include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, and di-n-propyl. Amine, triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1,5-diazabicyclo -An alkaline aqueous solution in which at least one of alkaline compounds such as [4.3.0] -5-nonene is dissolved is preferable.
The concentration of the alkaline aqueous solution is usually 10% by mass or less. In this case, if the concentration of the alkaline aqueous solution exceeds 10% by mass, the unexposed area may be dissolved in the developer, which is not preferable.

An organic solvent can also be added to the developer composed of the alkaline aqueous solution. Examples of the organic solvent include ketones such as acetone, methyl ethyl ketone, methyl i-butyl ketone, cyclopentanone, cyclohexanone, 3-methylcyclopentanone, and 2,6-dimethylcyclohexanone; methyl alcohol, ethyl alcohol, and n-propyl. Alcohols such as alcohol, i-propyl alcohol, n-butyl alcohol, t-butyl alcohol, cyclopentanol, cyclohexanol, 1,4-hexanediol, 1,4-hexanedimethylol; ethers such as tetrahydrofuran and dioxane Esters such as ethyl acetate, n-butyl acetate and i-amyl acetate; aromatic hydrocarbons such as toluene and xylene; phenol, acetonylacetone and dimethylformamide. These organic solvents can be used alone or in admixture of two or more.
The amount of the organic solvent used is preferably 100% by volume or less with respect to the alkaline aqueous solution. In this case, when the amount of the organic solvent used exceeds 100% by volume, the developability is lowered, and there is a possibility that the remaining development in the exposed area increases. An appropriate amount of a surfactant or the like can be added to the developer composed of the alkaline aqueous solution.
In addition, after developing with the developing solution which consists of alkaline aqueous solution, generally it wash | cleans with water and dries.

Further, in the reference invention, in order to maximize the potential of the resin composition, it is used as disclosed in, for example, Japanese Examined Patent Publication No. 6-12452 (Japanese Patent Laid-Open No. 59-93448). An organic or inorganic antireflection film can be formed on the substrate. In order to prevent the influence of basic impurities contained in the environmental atmosphere, a protective film can be provided on the photoresist film as disclosed in, for example, Japanese Patent Laid-Open No. 5-188598. Furthermore, in order to prevent the acid generator and the like from flowing out of the photoresist film, an immersion protective film can be provided on the photoresist film as disclosed in, for example, Japanese Patent Application Laid-Open No. 2005-352384. . These techniques can be used in combination.

In the step (2), an inactivation process is performed so that the formed first resist pattern is inactive to light. In the reference invention, “inactive to light” means that the resin component is not exposed to light by exposure to radiation or the like. That is, the inactivated pattern does not become alkali-soluble even when exposed.
Examples of such inactivation processing include exposure processing and heat processing.
Specific examples of the exposure process include a method of irradiating the above-described radiation with an exposure amount 2 to 10 times the optimum exposure amount at the time of forming the first resist pattern.
Moreover, as a specific heat treatment, for example, there is a method of heating at a temperature higher than the PEB temperature at the time of forming the first resist pattern.
In addition, these inactivation processes may be performed only 1 type and may be performed 2 or more types.

In the step (3), the second resist layer forming resin composition is applied onto the substrate on which the first resist pattern is formed by an appropriate application means such as spin coating, cast coating, roll coating or the like. A second resist layer is formed. In the reference invention, since the solvent that does not dissolve the first resist pattern is selected and used as the solvent for the resin composition for forming the second resist layer, the first resist pattern is used without mixing. Two resist layers can be formed.
Although the thickness of this 2nd resist layer is not specifically limited, Usually, it is 10-1000 nm, Preferably it is 10-500 nm.
Moreover, after apply | coating the resin composition for 2nd resist layer formation, you may volatilize the solvent in a coating film by prebaking (PB) as needed. Although the prebaking heating conditions are appropriately selected depending on the composition of the resin composition, it is generally about 30 to 200 ° C, preferably 50 to 150 ° C.

Then, in the step (3), the main area at the second resist layer formed, through a mask having a predetermined pattern, irradiated by exposing, the pattern latent image portion (exposed to the second resist layer, alkali Insoluble part) is formed.
The exposure method is not particularly limited, but it is preferable to use an immersion exposure method. When using the immersion exposure method, the radiation is in the main region at a second resist layer, through a liquid for liquid immersion lithography and such as water or a fluorine-based inert liquid through a mask having a predetermined pattern illuminated Is done.

In the step (4), the exposed second resist layer is developed to expose the pattern latent image portion, and a positive second resist pattern is formed in the space portion of the first resist pattern.
The space portion of the first resist pattern means a portion where the resist film is peeled off by dissolving the resist during development.
The developing method is the same as the developing method in step (1).

Hereinafter, a specific example of the pattern forming method of the reference invention including the steps (1), (2), (3) and (4) will be described with reference to FIG.
In the step (1), as shown in FIG. 1 (a), the main area at the first resist layer 2 formed on the substrate 1 by using the first resist layer forming resin composition, a predetermined pattern Then, exposure is performed by irradiation of radiation through an immersion exposure liquid such as water or air 3 (see the arrow in the figure), and a pattern latent image portion 21 is formed in the first resist layer 2. The Thereafter, by development, a first resist pattern 22 (1L3S) is formed on the substrate 1 as shown in FIG.
Next, in the step (2), as shown in FIG. 1C, the first resist pattern 22 is exposed to radiation (see arrows in the figure), and the first resist pattern 22 is formed. The pattern 23 becomes inactive to light.
Then, in the said process (3), as shown in FIG.1 (d), the 2nd resist layer formed on the board | substrate 1 provided with the 1st resist pattern 22 using the resin composition for 2nd resist layer formation. the main region at the 5, through the immersion exposure liquid 6 and such as water through a mask 7 having a predetermined pattern, exposure by irradiation with radiation is performed (see the arrows in FIG.), the second resist layer 5 pattern A latent image portion 51 is formed.
Next, in the step (4), as shown in FIG. 1E, a second resist pattern 52 is formed in the space portion of the first resist pattern 23 that has been deactivated by development. In addition, a 1L1S resist pattern in which the first resist pattern 23 and the second resist pattern 52 are alternately arranged is formed.

The resist pattern forming method of the present invention includes the following steps (i) to (iii).
Step (i): Using the positive-type radiation-sensitive resin composition for forming the first resist layer, a first resist layer is formed on the substrate, and exposure is performed by irradiating a required region of the first resist layer with radiation. And then developing to form a first resist pattern
Step (ii): After forming the second resist layer on the substrate on which the first resist pattern is formed using the positive radiation-sensitive composition for forming the second resist layer, the second resist layer and Irradiating a required region of the first resist pattern with radiation to inactivate the first resist pattern with respect to light and forming a pattern latent image portion on the second resist layer
Step (iii); Step of forming a second resist pattern in the space portion of the first resist pattern by developing
That is , in the resist pattern forming method of the present invention, the following step (2 ′) is provided instead of the steps (2) and (3) in the reference invention, and the step (1) [in step (i) Corresponding] , this step (2 ′) [corresponding to step (ii)] and the above step (4) [corresponding to step (iii)] can be provided.
Step (2 ′): After forming a second resist layer on the substrate on which the first resist pattern is formed using the second resist layer forming resin composition, the second resist layer and the first resist by exposing by irradiating radiation at a main area of the pattern, the causes inactivated to light the first resist pattern, forming a pattern latent image portion on the second resist layer

  In the step (2 '), first, the second resist layer forming resin composition is applied onto the substrate on which the first resist pattern is formed, thereby forming a second resist layer. In this case, the thickness of the second resist layer is the same as described above. Moreover, after apply | coating the resin composition for 2nd resist layer formation, you may volatilize the solvent in a coating film by prebaking (PB) as needed. The prebaking heating conditions are the same as described above.

Then, the main region at a second resist layer and the first resist pattern formed through the liquid for liquid immersion lithography and such as water or a fluorine-based inert liquid through a mask having a predetermined pattern, radiation is irradiated Exposed. At this time, a pattern latent image portion (portion that has become insoluble in alkali by exposure) is formed in the second resist layer, and the first resist pattern is inactivated. Therefore, when the step (2 ′) is provided, it is not necessary to perform the inactivation processing step by exposure alone, and the number of exposures can be reduced, which is economical.

  Further, the exposure condition in the step (2 ′) is preferably an exposure amount 2 to 10 times the optimum exposure amount at the time of forming the first resist pattern, and an optimum exposure amount for forming the second resist pattern. .

Hereinafter, a specific example of the pattern forming method of the present invention including the steps (1), (2 ′) and (4) will be described with reference to FIG.
In the step (1), as shown in FIG. 2 (a), the main area at the first resist layer 2 formed on the substrate 1 by using the first resist layer forming resin composition, a predetermined pattern Then, exposure is performed by irradiation of radiation through an immersion exposure liquid such as water or air 3 (see the arrow in the figure), and a pattern latent image portion 21 is formed in the first resist layer 2. The Thereafter, by development, a first resist pattern 22 (1L3S) is formed on the substrate 1 as shown in FIG.
Next, in the step (2 ′), as shown in FIG. 2C, a second resist formed on the substrate 1 having the first resist pattern 22 by using the second resist layer forming resin composition. where essential regions of the layer 5 and, for the first resist pattern 22 via the liquid for liquid immersion lithography 6 and such as water through a mask 7 having a predetermined pattern, exposure by irradiation with radiation is performed (in FIG. The pattern latent image portion 51 is formed on the second resist layer 5 and the first resist pattern 22 is inactivated.
Next, in the step (4), as shown in FIG. 2D, a second resist pattern 52 is formed in the space portion of the first resist pattern 23 that has been deactivated by development. In addition, a 1L1S resist pattern in which the first resist pattern 23 and the second resist pattern 52 are alternately arranged is formed.

[2] Positive-type radiation-sensitive resin composition for forming the second resist layer The resin composition for forming the second resist layer of the present invention is used when forming the second resist layer in the resist pattern forming method described above. A resin composition comprising a resin (A) that becomes alkali-soluble by the action of an acid and a solvent (B).

<Resin that becomes alkali-soluble by the action of acid (A)>
The “resin (A) that becomes alkali-soluble by the action of an acid” (hereinafter referred to as “resin (A)”) is an alkali-insoluble or hardly-soluble resin that becomes alkali-soluble by the action of an acid. The term “alkali-insoluble or alkali-insoluble” as used herein refers to alkali development conditions employed when a resist pattern is formed from a resist film formed from the resin composition for forming a second resist layer containing the resin (A). Below, when the film which uses only resin (A) instead of this resist film is developed, it means the property that 50% or more of the initial film thickness of this film remains after development.

  The resin (A) in the present invention is not particularly limited as long as it becomes alkali-soluble by the action of an acid. For example, a repeating unit represented by the following formula (1) (hereinafter referred to as “repeating unit (1)”) And a repeating unit represented by the following formula (2) containing a skeleton that becomes alkali-soluble by the action of an acid (hereinafter also referred to as “repeating unit (2)”).

〔一般式（１）において、Ｒ^１は水素原子、メチル基又はトリフルオロメチル基を示し、Ｒ^２は単結合、メチレン、炭素数２〜６の直鎖状或いは分岐状のアルキレン基、又は、炭素数４〜１２の脂環式のアルキレン基を示す。〕

[In General Formula (1), R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group, and R ² represents a single bond, methylene, a linear or branched alkylene group having 2 to 6 carbon atoms, or An alicyclic alkylene group having 4 to 12 carbon atoms is shown. ]

〔一般式（２）において、Ｒ^３は水素原子、メチル基又はトリフルオロメチル基を示す。各々のＲ^４は相互に独立に炭素数４〜２０の１価の脂環式炭化水素基若しくはその誘導体、又は炭素数１〜４の直鎖状若しくは分岐状のアルキル基を示す。〕

[In General Formula (2), R ³ represents a hydrogen atom, a methyl group or a trifluoromethyl group. Each R ⁴ independently represents a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof, or a linear or branched alkyl group having 1 to 4 carbon atoms. ]

R ^{2 in the} general formula (1) is a single bond, methylene, a linear or branched alkylene group having 2 to 6 carbon atoms, or an alicyclic alkylene group having 4 to 12 carbon atoms. It may be a group or an alkylene ester group.

Preferred examples of R ² include a propylene group such as a methylene group, an ethylene group, a 1,3-propylene group, or a 1,2-propylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group, and an octamethylene group. Group, nonamethylene group, decamethylene group, undecamethylene group, dodecamethylene group, tridecamethylene group, tetradecamethylene group, pentadecamethylene group, hexadecamethylene group, heptacamethylene group, octadecamethylene group, nonacamethylene group Group, 1-methyl-1,3-propylene group, 2-methyl-1,3-propylene group, 2-methyl-1,2-propylene group, 1-methyl-1,4-butylene group, 2-methyl-1 , 4-butylene group, methylidene group, ethylidene group, propylidene group, 2-propylidene group, etc. A saturated chain hydrocarbon group; a cyclobutylene group such as 1,3-cyclobutylene group; a cyclopentylene group such as 1,3-cyclopentylene group; a cyclohexylene group such as 1,4-cyclohexylene group; Monocyclic hydrocarbon ring groups such as cycloalkylene groups having 3 to 10 carbon atoms such as cyclooctylene groups such as 1,5-cyclooctylene groups; norbornylene such as 1,4-norbornylene groups or 2,5-norbornylene groups Groups, bridged cyclic hydrocarbon ring groups such as 2 to 4 cyclic hydrocarbon ring groups having 4 to 30 carbon atoms such as adamantylene groups such as 1,5-adamantylene group and 2,6-adamantylene group, etc. Is mentioned. Among these, R ² is preferably a hydrocarbon group containing a 2,5-norbornylene group, a 1,2-ethylene group, or a propylene group.

When R ² contains a divalent aliphatic cyclic hydrocarbon group, an alkylene group having 1 to 4 carbon atoms is inserted as a spacer between the bistrifluoromethyl-hydroxy-methyl group and the aliphatic cyclic hydrocarbon group. It is preferable to do.

Monomers that give the repeating unit (1) 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 and the like are preferable.

  In the resin (A), only one type of the repeating unit (1) may be contained, or two or more types may be contained.

In the general formula (2), examples of the monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms of R ⁴ include norbornane, tricyclodecane, tetracyclododecane, adamantane, cyclobutane, cyclopentane, cyclohexane, Groups composed of alicyclic rings derived from cycloalkanes such as cycloheptane and cyclooctane; groups composed of these alicyclic rings include, for example, methyl group, ethyl group, n-propyl group, i-propyl group 1 or more or 1 or more of linear, branched or cyclic alkyl groups having 1 to 4 carbon atoms such as n-butyl group, 2-methylpropyl group, 1-methylpropyl group and t-butyl group. Examples include substituted groups. Further, any two R ⁴ may be bonded to each other to form a divalent alicyclic hydrocarbon group or a derivative thereof together with the carbon atom to which each R ⁴ is bonded. Among these alicyclic hydrocarbon groups, a group consisting of an alicyclic ring derived from norbornane, tricyclodecane, tetracyclododecane, adamantane, cyclopentane or cyclohexane, or a group consisting of these alicyclic rings is described above. A group substituted with an alkyl group is preferred.

Examples of the linear or branched alkyl group having 1 to 4 carbon atoms in R ⁴ of the general formula (2) include, for example, methyl group, ethyl group, n-propyl group, i-propyl group, n- A butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group and the like can be mentioned.

In the general formula (2), preferred examples of —C (R ⁴ ) ₃ include t-butyl group, 1-n- (1-ethyl-1-methyl) propyl group, 1-n- (1,1- Dimethyl) propyl group, 1-n- (1,1-dimethyl) butyl group, 1-n- (1,1-dimethyl) pentyl group, 1- (1,1-diethyl) propyl group, 1-n- ( 1,1-diethyl) butyl group, 1-n- (1,1-diethyl) pentyl group, 1- (1-methyl) cyclopentyl group, 1- (1-ethyl) cyclopentyl group, 1- (1-n- Propyl) cyclopentyl group, 1- (1-i-propyl) cyclopentyl group, 1- (1-methyl) cyclohexyl group, 1- (1-ethyl) cyclohexyl group, 1- (1-n-propyl) cyclohexyl group, 1 -(1-i-propyl) 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-i-propyl) norbornyl group, 2 -(2-methyl) tetracyclodecanyl group, 2- (2-ethyl) tetracyclodecanyl group, 2- (2-n-propyl) tetracyclodecanyl group, 2- (2-i-propyl) tetra Cyclodecanyl group, 1- (1-methyl) adamantyl group, 1- (1-ethyl) adamantyl group, 1- (1-n-propyl) adamantyl group, 1- (1-i-propyl) adamantyl group, A group consisting of these alicyclic rings is For example, straight chain having 1 to 4 carbon atoms such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group, etc. And a group substituted with one or more branched or cyclic alkyl groups.

Preferred monomers that give the repeating unit (2) include (meth) acrylic acid 2-methyladamantyl-2-yl ester, (meth) acrylic acid 2-methyl-3-hydroxyadamantyl-2-yl ester, (Meth) acrylic acid 2-ethyladamantyl-2-yl ester, (meth) acrylic acid 2-ethyl-3-hydroxyadamantyl-2-yl ester, (meth) acrylic acid 2-n-propyladamantyl-2-yl ester, (Meth) acrylic acid 2-isopropyladamantyl-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-8-methyltricyclo [5.2.1] 0 ^2,6] decan-8-yl ester, (meth) ethyl-8-acrylic acid tricyclo [5.2.1.0 ^2,6] decan-8-yl ester, (meth) acrylic acid-4- Methyltetracyclo [6.2.1 ^3,6 . 0 ^2,7 ] dodecan-4-yl ester, (meth) acrylic acid-4-ethyltetracyclo [6.2.1 ^3,6 . 0 ^2,7 ] dodecan-4-yl ester, (meth) acrylic acid 1- (bicyclo [2.2.1] hept-2-yl) -1-methylethyl ester, (meth) acrylic acid 1- (tricyclo [5.2.1.0 ^2,6 ] decan-8-yl) -1-methylethyl ester, (meth) acrylic acid 1- (tetracyclo [6.2.1 ^3,6.0 0.0 ^2,7 ] dodecane -4-yl) -1-methylethyl ester, (meth) acrylic acid 1- (adamantan-1-yl) -1-methylethyl ester, (meth) acrylic acid 1- (3-hydroxyadamantan-1-yl) -1-methyl ethyl ester, (meth) acrylic acid 1,1-dicyclohexylethyl ester, (meth) acrylic acid 1,1-di (bicyclo [2.2.1] hept-2-yl) ethyl ester, Meth) acrylic acid 1,1-di (tricyclo [5.2.1.0 ^2,6] decan-8-yl) ethyl ester, (meth) acrylic acid 1,1-di (tetracyclo [6.2.1 ^3,6 .0 ^2,7] dodecane-4-yl) ethyl ester, (meth) acrylic acid 1,1-di (adamantan-1-yl) ethyl ester, (meth) acrylic acid 1-methyl-1-cyclopentyl Examples include esters, (meth) acrylic acid 1-ethyl-1-cyclopentyl ester, (meth) acrylic acid 1-methyl-1-cyclohexyl ester, (meth) acrylic acid 1-ethyl-1-cyclohexyl ester, and the like.

  Among these monomers, (meth) acrylic acid 2-methyladamantyl-2-yl ester, (meth) acrylic acid 2-ethyladamantyl-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- Chill-1-cyclohexyl ester, and the like are particularly preferable.

  In the resin (A), only one type of the repeating unit (2) may be contained, or two or more types may be contained.

Moreover, the resin (A) in the resin composition for forming a second resist layer of the present invention may contain other repeating units in addition to the repeating unit (1) and the repeating unit (2).
Examples of the other repeating unit include a repeating unit containing a lactone skeleton (hereinafter also referred to as “repeating unit (3)”).
Examples of the repeating unit (3) include repeating units having groups (side chains) such as the following general formulas (3-1) to (3-6). The main chain skeleton of the repeating unit (3) is not particularly limited, but preferably has a structure such as methacrylic acid ester, acrylic acid ester, or α-trifluoroacrylic acid ester.

In the formulas (3-1) to (3-6), R ⁵ represents a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, and R ⁶ represents a hydrogen atom or a methoxy group. . A represents a single bond or a methylene group, and B represents an oxygen atom or a methylene group. Further, l represents an integer of 1 to 3, and m is 0 or 1.
Examples of the substituted or unsubstituted alkyl group having 1 to 4 carbon atoms in R ⁵ of the general formula (3-1) include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, and n-butyl. Group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group and the like.

As a preferable monomer that gives the repeating unit (3), for example, (meth) acrylic acid-5-oxo-4-oxa-tricyclo [4.2.1.0 ^3,7 ] non-2-yl ester , (Meth) acrylic acid-9-methoxycarbonyl-5-oxo-4-oxa-tricyclo [4.2.1.0 ^3,7 ] non-2-yl ester, (meth) acrylic acid-5-oxo- 4-Oxa-tricyclo [5.2.1.0 ^3,8 ] dec-2-yl ester, (meth) acrylic acid-10-methoxycarbonyl-5-oxo-4-oxa-tricyclo [5.2.1 0.0 ^3,8 ] non-2-yl ester, (meth) acrylic acid-6-oxo-7-oxa-bicyclo [3.2.1] oct-2-yl ester, (meth) acrylic acid-4- Methoxycarbonyl-6- Xo-7-oxa-bicyclo [3.2.1] oct-2-yl ester, (meth) acrylic acid-7-oxo-8-oxa-bicyclo [3.3.1] oct-2-yl ester, (Meth) acrylic acid-4-methoxycarbonyl-7-oxo-8-oxa-bicyclo [3.3.1] oct-2-yl ester, (meth) acrylic acid-2-oxotetrahydropyran-4-yl ester , (Meth) acrylic acid-4-methyl-2-oxotetrahydropyran-4-yl ester, (meth) acrylic acid-4-ethyl-2-oxotetrahydropyran-4-yl ester, (meth) acrylic acid-4 -Propyl-2-oxotetrahydropyran-4-yl ester, (meth) acrylic acid-5-oxotetrahydrofuran-3-yl ester, (meth) acrylic Luric acid-2,2-dimethyl-5-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-4,4-dimethyl-5-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-2-oxo Tetrahydrofuran-3-yl ester, (meth) acrylic acid-4,4-dimethyl-2-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-5,5-dimethyl-2-oxotetrahydrofuran-3-yl ester , (Meth) acrylic acid-2-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-5-oxotetrahydrofuran-2-ylmethyl ester, (meth) acrylic acid-3,3-dimethyl-5-oxotetrahydrofuran -2-ylmethyl ester, (meth) acrylic acid-4,4-dimethyl 5-oxo tetrahydrofuran-2-yl methyl ester, and the like.

  The resin (A) may contain only one type of the repeating unit (3), or two or more types.

  Furthermore, as the other repeating unit, a repeating unit represented by the following general formula (4) (hereinafter, also referred to as “repeating unit (4)”), a repeating unit represented by the following general formula (5) (hereinafter referred to as “repeating unit”) And “repeating unit (5)”).

〔一般式（４）中、Ｒ^７は水素原子、メチル基、又はトリフルオロメチル基を示し、Ｘは炭素数７〜２０の置換又は非置換の多環型脂環式炭化水素基であり、この多環型脂環式炭化水素基が置換基を有する場合、置換基は炭素数１〜４のアルキル基、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である。〕

[In General Formula (4), R ⁷ represents a hydrogen atom, a methyl group, or a trifluoromethyl group, X is a substituted or unsubstituted polycyclic alicyclic hydrocarbon group having 7 to 20 carbon atoms, When this polycyclic alicyclic hydrocarbon group has a substituent, the substituent is an alkyl group having 1 to 4 carbon atoms, a hydroxyl group, a cyano group, or a hydroxyalkyl group having 1 to 10 carbon atoms. ]

Examples of the substituted or unsubstituted polycyclic alicyclic hydrocarbon group having 7 to 20 carbon atoms in X of the repeating unit (4) include bicyclo [2.2.1] heptane (4a) represented by the following formula: , Bicyclo [2.2.2] octane (4b), tricyclo [5.2.1.0 ^2,6 ] decane (43c), tetracyclo [6.2.1.1 ^3,6 . And hydrocarbon groups derived from cycloalkanes such as 0 ^2,7 ] dodecane (4d) and tricyclo [3.3.1.1 ^3,7 ] decane (4e).

  When the hydrocarbon group derived from the 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, 2- Examples thereof include linear, branched or cyclic alkyl groups having 1 to 4 carbon atoms such as methylpropyl group, 1-methylpropyl group and t-butyl group. In addition, it is not limited to what was substituted by these alkyl groups, The thing substituted by the hydroxyl group, the cyano group, the C1-C10 hydroxyalkyl group, the carboxyl group, and oxygen may be used.

As a monomer for constituting the repeating unit (4), for example, (meth) acrylic acid-bicyclo [2.2.1] heptyl ester, (meth) acrylic acid-cyclohexyl ester, (meth) acrylic acid- Bicyclo [4.4.0] decanyl ester, (meth) acrylic acid-bicyclo [2.2.2] octyl ester, (meth) acrylic acid-tricyclo [5.2.1.0 ^2,6 ] decanyl Esters, (meth) acrylic acid-tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecanyl ester, (meth) acrylic acid-tricyclo [3.3.1.1 ^3,7 ] decanyl ester, and the like.

  In the resin (A), only one type of the repeating unit (4) may be contained, or two or more types may be contained.

〔一般式（５）中、Ｒ^８は水素原子又はメチル基を示し、Ｘは単結合又は炭素数１〜３の２価の有機基を示し、Ｙは相互に独立に、単結合又は炭素数１〜３の２価の有機基を示し、Ｒ^９は相互に独立に、水素原子、水酸基、シアノ基、又はＣＯＯＲ^１０で表される基を示す。但し、前記Ｒ^１０は水素原子、炭素数１〜４の直鎖状若しくは分岐状のアルキル基、又は炭素数３〜２０の脂環式のアルキル基を示す。尚、３つのＲ^９のうち少なくとも一つは水素原子でなく、かつ、Ｘが単結合の場合、３つのＹのうち少なくとも一つは炭素数１〜３の２価の有機基を示す。〕

[In General Formula (5), R ⁸ represents a hydrogen atom or a methyl group, X represents a single bond or a divalent organic group having 1 to 3 carbon atoms, and Y represents a single bond or carbon number independently of each other. 1 to 3 represent divalent organic groups, and R ⁹ independently represents a hydrogen atom, a hydroxyl group, a cyano group, or a group represented by COOR ¹⁰ . However, the R ¹⁰ represents a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, or an alicyclic alkyl group having 3 to 20 carbon atoms. At least one of the three R ⁹ is not hydrogen atom, and when X is a single bond, at least one of the three Y is a divalent organic group having 1 to 3 carbon atoms. ]

  As a C1-C3 bivalent organic group of X and Y of a repeating unit (5), a methylene group, ethylene group, a propylene group etc. can be mentioned, for example.

Examples of the linear or branched alkyl group having 1 to 4 carbon atoms of R ¹⁰ of the group represented by COOR ¹⁰ include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, and n-butyl. Group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group and the like.

^Examples of the alicyclic alkyl group having 3 to 20 carbon atoms ^{R 10,} for _example, -C _{n H 2n-1} cycloalkyl group (n is an integer of 3 to 20) represented by the polycyclic alicyclic Examples thereof include a cyclic alkyl group. Examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Examples of the polycyclic alicyclic alkyl group include a bicyclo [2.2.1] heptyl group, a tricyclo [5.2.1.0 ^2,6 ] decyl group, and a tetracyclo [6.2.1]. ^3,6 . 0 ^2,7 ] dodecanyl group, adamantyl group and the like. In the cycloalkyl group and the polycyclic alicyclic alkyl group, one or more linear, branched or cyclic alkyl groups may be substituted as substituents. May be.

  As a monomer for constituting the repeating unit (5), for example, (meth) acrylic acid 3-hydroxyadamantan-1-ylmethyl ester, (meth) acrylic acid 3,5-dihydroxyadamantan-1-ylmethyl Ester, (meth) acrylic acid 3-hydroxy-5-methyladamantan-1-yl ester, (meth) acrylic acid 3,5-dihydroxy-7-methyladamantan-1-yl ester, (meth) acrylic acid 3-hydroxy Examples include -5,7-dimethyladamantan-1-yl ester and (meth) acrylic acid 3-hydroxy-5,7-dimethyladamantan-1-ylmethyl ester.

  In the resin (A), only one type of the repeating unit (5) may be contained, or two or more types may be contained.

  Moreover, as another repeating unit other than the repeating units (3) to (5), for example, it has a bridged hydrocarbon skeleton such as dicyclopentenyl (meth) acrylate and adamantylmethyl (meth) acrylate ( Bridged carbonization of unsaturated carboxylic acids such as (meth) acrylic acid esters; carboxynorbornyl (meth) acrylate, carboxytricyclodecanyl (meth) acrylate, carboxytetracycloundecanyl (meth) acrylate Carboxyl group-containing esters having a hydrogen skeleton;

  Methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, 2-methylpropyl (meth) acrylate, 1-methyl (meth) acrylate Propyl, t-butyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, cyclopropyl (meth) acrylate, ( (Meth) acrylic acid cyclopentyl, (meth) acrylic acid cyclohexyl, (meth) acrylic acid 4-methoxycyclohexyl, (meth) acrylic acid 2-cyclopentyloxycarbonylethyl, (meth) acrylic acid 2-cyclohexyloxycarbonylethyl, (meth) 2- (4-Methoxycyclohexyl) acrylic acid No bridged hydrocarbon skeleton such as aryloxycarbonyl ethyl (meth) acrylate;

  α-hydroxymethyl acrylate esters such as methyl α-hydroxymethyl acrylate, ethyl α-hydroxymethyl acrylate, n-propyl α-hydroxymethyl acrylate, n-butyl α-hydroxymethyl acrylate; (meth) acrylonitrile , Α-chloroacrylonitrile, crotonnitrile, maleinonitrile, fumaronitrile, mesaconitrile, citraconitrile, itaconnitrile, and other unsaturated nitrile compounds; (meth) acrylamide, N, N-dimethyl (meth) acrylamide, crotonamide, maleinamide , Fumaramide, mesaconamide, citraconic amide, itaconic amide, etc .; N- (meth) acryloylmorpholine, N-vinyl-ε-caprolactam, N-vinylpyrrolidone, vinyl Other nitrogen-containing vinyl compounds such as lysine and vinylimidazole; (meth) acrylic acid, crotonic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride, mesaconic acid, etc. Unsaturated carboxylic acids (anhydrides); 2-carboxyethyl (meth) acrylate, 2-carboxypropyl (meth) acrylate, 3-carboxypropyl (meth) acrylate, 4-carboxybutyl (meth) acrylate, Carboxyl group-containing esters having no bridged hydrocarbon skeleton of unsaturated carboxylic acid such as (meth) acrylic acid 4-carboxycyclohexyl;

  1,2-adamantanediol di (meth) acrylate, 1,3-adamantanediol di (meth) acrylate, 1,4-adamantanediol di (meth) acrylate, tricyclodecanyl dimethylol di (meth) acrylate, etc. A polyfunctional monomer having a bridged hydrocarbon skeleton;

  Methylene glycol di (meth) acrylate, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 2,5-dimethyl-2,5-hexanediol di ( (Meth) acrylate, 1,8-octanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,4-bis (2-hydroxypropyl) benzenedi (meth) acrylate, 1,3-bis List units in which a polymerizable unsaturated bond of a polyfunctional monomer such as a polyfunctional monomer having no bridged hydrocarbon skeleton such as (2-hydroxypropyl) benzenedi (meth) acrylate is cleaved Can do.

  Of these other repeating units, a repeating unit in which a polymerizable unsaturated bond of (meth) acrylic acid ester having a bridged hydrocarbon skeleton is cleaved is preferable.

  The resin (A) of the present invention preferably contains at least one other repeating unit selected from the group consisting of these other repeating units.

  When the content of the repeating unit (1) in the resin (A) of the resin composition for forming a second resist layer of the present invention is 100 mol%, the total of all repeating units contained in the resin (A) is 100 mol%. It is preferable that it is 30-90 mol%, More preferably, it is 30-80 mol%, More preferably, it is 40-80 mol%. When the content rate of this repeating unit (1) is less than 30 mol%, there exists a possibility that the solubility to the alcohol solvent of resin may fall. On the other hand, when it exceeds 90 mol%, the resolution as a resist film may be deteriorated.

  The content of the repeating unit (2) is preferably 10 to 70 mol%, more preferably 10 to 60 mol, when the total of all repeating units contained in the resin (A) is 100 mol%. It is mol%, More preferably, it is 20-60 mol%. When the content rate of this repeating unit (2) is less than 10 mol%, there exists a possibility that the resolution as a resist film may deteriorate. On the other hand, when it exceeds 70 mol%, the developability of the resist film may be deteriorated.

  The content of the repeating unit (3) is preferably 50 mol% or less, more preferably 40 mol% or less, when the total of all repeating units contained in the resin (A) is 100 mol%. More preferably, it is 35 mol% or less. When the content rate of this repeating unit (3) exceeds 50 mol%, there exists a possibility that it may become impossible to have sufficient refractive index in wavelength 193nm.

  The content of the repeating unit (4) is preferably 30 mol% or less, more preferably 25 mol% or less, when the total of all repeating units contained in the resin (A) is 100 mol%. It is. When the content rate of this repeating unit (4) exceeds 30 mol%, there exists a possibility that the resist film obtained may become easy to swell with an alkali developing solution, or the solubility with respect to an alkaline developing solution may fall.

  The content of the repeating unit (5) is preferably 30 mol% or less, more preferably 25 mol% or less, when the total of all repeating units contained in the resin (A) is 100 mol%. It is. When the content rate of this repeating unit (5) exceeds 30 mol%, the obtained resist film may be easily swollen by the alkali developer, or the solubility in the alkali developer may be reduced.

  The content of other repeating units [total of repeating units other than the repeating units (1) and (2)] is preferably 50 mol% or less with respect to all repeating units in the resin (A). More preferably, it is 40 mol% or less.

  In addition, the resin composition for 2nd resist layer formation may contain 1 type of resin (A), and may contain 2 or more types.

  Resin (A) in the present invention is, for example, a polymerizable unsaturated monomer for constituting each of the above-mentioned repeating units, radicals such as hydroperoxides, dialkyl peroxides, diacyl peroxides, and azo compounds. It can be prepared by polymerizing in a suitable solvent using a polymerization initiator and optionally in the presence of a chain transfer agent.

Examples of the solvent used for the polymerization include alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane; cyclohexane, cycloheptane, cyclooctane, decalin, Cycloalkanes such as norbornane; aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene; halogenated hydrocarbons such as chlorobutanes, bromohexanes, dichloroethane, hexamethylene dibromide, chlorobenzene; ethyl acetate Saturated carboxylic acid esters such as n-butyl acetate, i-butyl acetate and methyl propionate; ketones such as acetone, 2-butanone, 4-methyl-2-pentanone and 2-heptanone; tetrahydrofuran, dimethoxyethanes, Ethers such as diethoxyethanes It can be mentioned. In addition, these solvents can be used individually or in mixture of 2 or more types.
Moreover, the reaction temperature in the said polymerization is 40-150 degreeC normally, Preferably it is 50-120 degreeC, and reaction time is 1-48 hours normally, Preferably it is 1-24 hours.

The molecular weight of the resin (A) in the present invention is not particularly limited, but the polystyrene-equivalent weight average molecular weight (hereinafter also referred to as “Mw”) by gel permeation chromatography (GPC) is preferably 1000 to 100,000. Preferably it is 1000-30000, More preferably, it is 1000-20000. If the Mw of the resin (A) is less than 1000, the heat resistance may be lowered when a resist film is formed. On the other hand, if this Mw exceeds 100,000, the developability may be lowered when a resist film is formed.
Further, the ratio (Mw / Mn) of Mw of the resin (A) to polystyrene-reduced number average molecular weight (hereinafter also referred to as “Mn”) by gel permeation chromatography (GPC) is usually 1 to 5, preferably Is 1-3.

  Moreover, the low molecular weight component derived from the monomer used when preparing resin may be contained in resin (A) in this invention. The content of the low molecular weight component is preferably 0.1% by mass or less, more preferably 0.07% by mass or less, further preferably 100% by mass (in terms of solid content) of the resin (A). It is 0.05 mass% or less. When this content is 0.1% by mass or less, no foreign matter is generated in the resist when the resist is stored, and there is no coating unevenness even when the resist is applied. It can be sufficiently suppressed. Furthermore, when the exposure is performed by the immersion exposure method, it is possible to reduce the amount of the eluate in the immersion exposure liquid such as water that is in contact with the exposure.

  The low molecular weight component may be a component having an Mw of 500 or less, and specifically includes a monomer, a dimer, a trimer, and an oligomer. This low molecular weight component (component of Mw 500 or less) is, for example, chemical purification methods such as washing with water, liquid-liquid extraction, etc., and combinations of these chemical purification methods with physical purification methods such as ultrafiltration and centrifugation, etc. Can be removed. The analysis can be performed by high performance liquid chromatography (HPLC).

Further, the resin (A) preferably has few impurities such as halogen and metal, and by reducing such impurities, the sensitivity, resolution, process stability, pattern shape, etc. of the resist film to be formed are reduced. Further improvements can be made.
Examples of the purification method of the resin (A) include chemical purification methods such as washing with water and liquid-liquid extraction, and combinations of these chemical purification methods and physical purification methods such as ultrafiltration and centrifugation. be able to.

<Solvent (B)>
As the “solvent (B)”, a solvent that does not dissolve the first resist pattern formed in the pattern forming method of the present invention is selected. That is, the one that is difficult to mix with the first resist pattern is selected.

As such a solvent (B), an alcohol solvent is preferable. The alcohol solvent in the present invention means (1) a solvent composed of an alcohol solvent, or (2) a solvent composed of an alcohol solvent and another solvent.
Examples of the alcohol solvent include 1-butyl alcohol, 2-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, tert-amyl alcohol, neopentyl alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, 2,3-dimethyl-2-butanol 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-diethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl -3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pe Pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, and the like.

  Examples of the other solvent include diethyl ether, dipropyl ether, diisopropyl ether, butyl methyl ether, butyl ethyl ether, butyl propyl ether, dibutyl ether, diisobutyl ether, tert-butyl methyl ether, tert-butyl ethyl ether. Tert-butylpropyl ether, di-tert-butyl ether, dipentyl ether, diisoamyl ether, dihexyl ether, dioctyl ether, cyclopentyl methyl ether, cyclohexyl methyl ether, cyclododecyl methyl ether, cyclopentyl ethyl ether, cyclohexyl ethyl ether, cyclopentyl propyl ether , Cyclopentyl-2-propyl ether, cyclohexylpropyl ether Cyclohexyl-2-propyl ether, cyclopentyl butyl ether, cyclopentyl-tert-butyl ether, cyclohexyl butyl ether, cyclohexyl-tert-butyl ether, bromomethyl methyl ether, iodomethyl methyl ether, α, α-dichloromethyl methyl ether, chloromethyl ethyl ether, 2 -Chloroethyl methyl ether, 2-bromoethyl methyl ether, 2,2-dichloroethyl methyl ether, 2-chloroethyl ethyl ether, 2-bromoethyl ethyl ether, (±) -1,2-dichloroethyl ethyl ether, di -2-bromoethyl ether, 2,2,2-trifluoroethyl ether, chloromethyl octyl ether, bromomethyl octyl ether, di-2-chloroethyl Ether, ethyl vinyl ether, butyl vinyl ether, allyl ethyl ether, allyl propyl ether, allyl butyl ether, diallyl ether, 2-methoxypropene, ethyl-1-propenyl ether, 1-methoxy-1,3-butadiene, cis-1-bromo- Examples include 2-ethoxyethylene, 2-chloroethyl vinyl ether, allyl-1,1,2,2-tetrafluoroethyl ether, and the like.

  Among these ethers, dipropyl ether, diisopropyl ether, butyl methyl ether, butyl ethyl ether, butyl propyl ether, dibutyl ether, diisobutyl ether, tert-butyl methyl ether, tert-butyl ethyl ether, tert-butyl propyl ether , Di-tert-butyl ether, dipentyl ether, diisoamyl ether, cyclopentyl methyl ether, cyclohexyl methyl ether, cyclopentyl ethyl ether, cyclohexyl ethyl ether, cyclopentyl propyl ether, cyclopentyl-2-propyl ether, cyclohexyl propyl ether, cyclohexyl-2-propyl Ether, cyclopentyl butyl ether, cyclopentyl-tert Butyl ether, cyclohexyl ether, cyclohexyl -tert- butyl ether and the like are preferable.

  Furthermore, examples of other solvents include octane, isooctane, nonane, decane, methylcyclohexane, decalin, xylene, amylbenzene, ethylbenzene, diethylbenzene, cumene, 2-butylbenzene, cymene, dipentene, and γ-butyrolactone.

  In addition, when the solvent (B) contains another solvent, the ratio of the other solvent is 60% by mass or less, preferably 50% by mass or less, when the solvent (B) is 100% by mass, More preferably, it is 40 mass% or less.

  In this invention, a solvent (B) can be used individually or in mixture of 2 or more types.

  The resin composition for forming a second resist layer of the present invention is usually used in the solvent (B) so that the total solid content concentration is usually 1 to 50% by mass, preferably 1 to 25% by mass when used. After dissolution, it is prepared, for example, by filtering with a filter having a pore size of about 0.2 μm.

<Radiosensitive acid generator>
The radiation-sensitive acid generator (hereinafter, also simply referred to as “acid generator”) in the present invention generates an acid upon exposure, and the acid dissociability existing in the resin component by the action of the generated acid. Group, specifically, the acid dissociable group of the repeating unit (2) is dissociated (the protecting group is eliminated), and as a result, the exposed portion of the resist film becomes readily soluble in an alkali developer, and a positive resist pattern It has the effect | action which forms.
As such an acid generator, what contains the compound (henceforth "the acid generator 1") represented by following General formula (6) is preferable.

（各式中、Ｒ^１５は、互いに独立して、フッ素原子を有し、且つ、炭素数１〜１０の直鎖状若しくは分岐状のアルキル基、又は、２つのＲ^１５が互いに結合して、フッ素原子を有し、且つ、炭素数２〜１０の２価の有機基であり、この２価の有機基は置換基を有してもよい。） In the general formula (6), R ¹¹ is a hydrogen atom, a fluorine atom, a hydroxyl group, a linear or branched alkyl group having 1 to 10 carbon atoms, or a linear or branched alkoxyl having 1 to 10 carbon atoms. A straight chain or branched alkoxycarbonyl group having 2 to 11 carbon atoms; R ¹² represents a linear or branched alkyl group having 1 to 10 carbon atoms, an alkoxyl group, or a linear, branched or cyclic alkanesulfonyl group having 1 to 10 carbon atoms. Further, R ¹³ independently represents a linear or branched alkyl group having 1 to 10 carbon atoms, an optionally substituted phenyl group or an optionally substituted naphthyl group, or two R ¹³ is bonded to each other to form a divalent group having 2 to 10 carbon atoms, the divalent group may be substituted, k is an integer of 0 to 2, and X ⁻ is Formula: R ¹⁴ C _n F _2n SO ₃ ⁻ , R ¹⁴ SO ₃ ⁻ (wherein R ¹⁴ represents a fluorine atom or an optionally substituted hydrocarbon group having 1 to 12 carbon atoms, and n is 1 Or an anion represented by the following general formula (7-1) or (7-2), and r is an integer of 0 to 10.

(In each formula, R ¹⁵ are independently of each other a fluorine atom and a linear or branched alkyl group having 1 to 10 carbon atoms, or two R ¹⁵ are bonded to each other, (It is a divalent organic group having 2 to 10 carbon atoms and having a fluorine atom, and this divalent organic group may have a substituent.)

In the general formula (6), examples of the linear or branched alkyl group having 1 to 10 carbon atoms represented by R ¹¹ , R ¹² and R ¹³ include a methyl group, an ethyl group, an n-propyl group, i- Propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group, n-pentyl group, neopentyl group, n-hexyl group, n-heptyl group, n-octyl group, 2- Examples thereof include an ethylhexyl group, an n-nonyl group, and an n-decyl group. Of these alkyl groups, a methyl group, an ethyl group, an n-butyl group, a t-butyl group, and the like are preferable.

Examples of the linear or branched alkoxyl group having 1 to 10 carbon atoms of R ¹¹ and R ¹² include, for example, a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, 2-methylpropoxy group, 1-methylpropoxy group, t-butoxy group, n-pentyloxy group, neopentyloxy group, n-hexyloxy group, n-heptyloxy group, n-octyloxy group, 2-ethylhexyloxy Group, n-nonyloxy group, n-decyloxy group and the like. Of these alkoxyl groups, a methoxy group, an ethoxy group, an n-propoxy group, an n-butoxy group, and the like are preferable.

Examples of the linear or branched alkoxycarbonyl group having 2 to 11 carbon atoms of R ¹¹ include, for example, a methoxycarbonyl group, an ethoxycarbonyl group, an n-propoxycarbonyl group, an i-propoxycarbonyl group, and n-butoxy. Carbonyl group, 2-methylpropoxycarbonyl group, 1-methylpropoxycarbonyl group, t-butoxycarbonyl group, n-pentyloxycarbonyl group, neopentyloxycarbonyl group, n-hexyloxycarbonyl group, n-heptyloxycarbonyl group, An n-octyloxycarbonyl group, a 2-ethylhexyloxycarbonyl group, an n-nonyloxycarbonyl group, an n-decyloxycarbonyl group, and the like can be given. Of these alkoxycarbonyl groups, a methoxycarbonyl group, an ethoxycarbonyl group, an n-butoxycarbonyl group, and the like are preferable.

Examples of the linear, branched, or cyclic alkanesulfonyl group having 1 to 10 carbon atoms of R ¹² include a methanesulfonyl group, an ethanesulfonyl group, an n-propanesulfonyl group, an n-butanesulfonyl group, a tert. -Butanesulfonyl group, n-pentanesulfonyl group, neopentanesulfonyl group, n-hexanesulfonyl group, n-heptanesulfonyl group, n-octanesulfonyl group, 2-ethylhexanesulfonyl group n-nonanesulfonyl group, n-decanesulfonyl Group, cyclopentanesulfonyl group, cyclohexanesulfonyl group and the like. Of these alkanesulfonyl groups, a methanesulfonyl group, an ethanesulfonyl group, an n-propanesulfonyl group, an n-butanesulfonyl group, a cyclopentanesulfonyl group, a cyclohexanesulfonyl group, and the like are preferable.

  Moreover, as r, 0-2 are preferable.

In the general formula (6), examples of the optionally substituted phenyl group represented by R ¹³ include a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, a 2,3-dimethylphenyl group, 2 , 4-dimethylphenyl group, 2,5-dimethylphenyl group, 2,6-dimethylphenyl group, 3,4-dimethylphenyl group, 3,5-dimethylphenyl group, 2,4,6-trimethylphenyl group, 4 -Substituted with phenyl groups such as ethylphenyl group, 4-t-butylphenyl group, 4-cyclohexylphenyl group, 4-fluorophenyl group or linear, branched or cyclic alkyl groups having 1 to 10 carbon atoms. These phenyl groups or alkyl-substituted phenyl groups can be converted into hydroxyl groups, carboxyl groups, cyano groups, nitro groups, alkoxyl groups, alkoxyalkyl groups. And a group substituted with at least one group such as an alkyl group, an alkoxycarbonyl group, and an alkoxycarbonyloxy group.

  Among the substituents for the phenyl group and the alkyl-substituted phenyl group, examples of the alkoxyl group include methoxy group, ethoxy group, n-propoxy group, i-propoxy group, n-butoxy group, 2-methylpropoxy group, 1- Examples thereof include a linear, branched or cyclic alkoxyl group having 1 to 20 carbon atoms such as a methylpropoxy group, a t-butoxy group, a cyclopentyloxy group and a cyclohexyloxy group.

Examples of the alkoxyalkyl group include 2 to 21 carbon atoms such as a methoxymethyl group, an ethoxymethyl group, a 1-methoxyethyl group, a 2-methoxyethyl group, a 1-ethoxyethyl group, and a 2-ethoxyethyl group. And linear, branched or cyclic alkoxyalkyl groups.
Examples of the alkoxycarbonyl group include a methoxycarbonyl group, an ethoxycarbonyl group, an n-propoxycarbonyl group, an i-propoxycarbonyl group, an n-butoxycarbonyl group, a 2-methylpropoxycarbonyl group, and a 1-methylpropoxycarbonyl group. , T-butoxycarbonyl group, cyclopentyloxycarbonyl group, cyclohexyloxycarbonyl and the like, and straight chain, branched or cyclic alkoxycarbonyl groups having 2 to 21 carbon atoms.

Examples of the alkoxycarbonyloxy group include methoxycarbonyloxy group, ethoxycarbonyloxy group, n-propoxycarbonyloxy group, i-propoxycarbonyloxy group, n-butoxycarbonyloxy group, t-butoxycarbonyloxy group, Examples thereof include linear, branched or cyclic alkoxycarbonyloxy groups having 2 to 21 carbon atoms such as cyclopentyloxycarbonyl group and cyclohexyloxycarbonyl.
Examples of the optionally substituted phenyl group represented by R ¹² in the general formula (6) include a phenyl group, a 4-cyclohexylphenyl group, a 4-t-butylphenyl group, a 4-methoxyphenyl group, and a 4-t-butoxyphenyl group. Etc. are preferred.

Examples of the optionally substituted naphthyl group for R ¹³ include 1-naphthyl group, 2-methyl-1-naphthyl group, 3-methyl-1-naphthyl group, 4-methyl-1-naphthyl group, 4-methyl-1-naphthyl group, 5-methyl-1-naphthyl group, 6-methyl-1-naphthyl group, 7-methyl-1-naphthyl group, 8-methyl-1-naphthyl group, 2,3-dimethyl -1-naphthyl group, 2,4-dimethyl-1-naphthyl group, 2,5-dimethyl-1-naphthyl group, 2,6-dimethyl-1-naphthyl group, 2,7-dimethyl-1-naphthyl group, 2,8-dimethyl-1-naphthyl group, 3,4-dimethyl-1-naphthyl group, 3,5-dimethyl-1-naphthyl group, 3,6-dimethyl-1-naphthyl group, 3,7-dimethyl- 1-naphthyl group, 3,8-dimethyl-1-na Butyl group, 4,5-dimethyl-1-naphthyl group, 5,8-dimethyl-1-naphthyl group, 4-ethyl-1-naphthyl group 2-naphthyl group, 1-methyl-2-naphthyl group, 3-methyl A naphthyl group substituted with a naphthyl group such as a 2-naphthyl group or 4-methyl-2-naphthyl group or a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms; these naphthyl group or alkyl Examples include a group in which a substituted naphthyl group is substituted with at least one group such as a hydroxyl group, a carboxyl group, a cyano group, a nitro group, an alkoxyl group, an alkoxyalkyl group, an alkoxycarbonyl group, and an alkoxycarbonyloxy group. Can do.

  Examples of the alkoxyl group, alkoxyalkyl group, alkoxycarbonyl group and alkoxycarbonyloxy group as the substituent include the groups exemplified for the phenyl group and the alkyl-substituted phenyl group.

As the naphthyl group which may be substituted for R ¹³ in the general formula (6), 1-naphthyl group, 1- (4-methoxynaphthyl) group, 1- (4-ethoxynaphthyl) group, 1- (4- n-propoxynaphthyl) group, 1- (4-n-butoxynaphthyl) group, 2- (7-methoxynaphthyl) group, 2- (7-ethoxynaphthyl) group, 2- (7-n-propoxynaphthyl) group , 2- (7-n-butoxynaphthyl) group and the like are preferable.

In addition, the divalent group having 2 to 10 carbon atoms formed by bonding two R ¹³ to each other is preferably a 5-membered or 6-membered ring together with the sulfur atom in the general formula (6), particularly preferably 5 Groups that form member rings (ie, tetrahydrothiophene rings) are desirable.

Examples of the substituent for the divalent group include a hydroxyl group, a carboxyl group, a cyano group, a nitro group, an alkoxyl group, an alkoxyalkyl group, an alkoxy group exemplified as the substituent for the phenyl group and the alkyl-substituted phenyl group. Examples thereof include a carbonyl group and an alkoxycarbonyloxy group.
As R ¹³ in the general formula (6), a methyl group, an ethyl group, a phenyl group, a 4-methoxyphenyl group, a 1-naphthyl group, and two R ¹³ are bonded to each other to form a tetrahydrothiophene ring structure together with a sulfur atom. A divalent group is preferred.

X ⁻ in the general formula (6) is R ¹⁴ C _n F _2n SO ₃ ⁻ , R ¹⁴ SO ₃ ⁻ or an anion represented by the general formula (7-1) or (7-2). The —C _n F _2n — group in the case where X ⁻ is R ¹⁴ C _n F _2n SO ₃ ^— is a perfluoroalkylene group having n carbon atoms, but this group may be linear. However, it may be branched. Here, n is preferably 1, 2, 4 or 8.
As the hydrocarbon group which carbon atoms which may have 1 to 12 substituents of R ^14, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, a bridged alicyclic hydrocarbon group.
Specifically, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group, n-pentyl group, neopentyl group N-hexyl group, cyclohexyl group, n-heptyl group, n-octyl group, 2-ethylhexyl group, n-nonyl group, n-decyl group, norbornyl group, norbornylmethyl group, hydroxynorbornyl group, adamantyl group Etc.

R ¹⁵ in the case where X ⁻ is an anion represented by the general formula (7-1) or (7-2) has fluorine atoms independent of each other, and has 1 to 10 carbon atoms. May be a linear or branched alkyl group, or two R ¹⁵ may be bonded to each other to have a fluorine atom and be a divalent organic group having 2 to 10 carbon atoms. In that case, the divalent organic group may have a substituent.
In the general formula (7-1) or (7-2), when R ¹⁵ is a linear or branched alkyl group having 1 to 10 carbon atoms, a trifluoromethyl group, a pentafluoroethyl group, or a heptafluoro group. A propyl group, a nonafluorobutyl group, a dodecafluoropentyl group, a perfluorooctyl group, etc. are mentioned.
When R ¹⁵ is a divalent organic group having 2 to 10 carbon atoms, a tetrafluoroethylene group, a hexafluoropropylene group, an octafluorobutylene group, a decafluoropentylene group, an undecafluorohexylene group, etc. Can be mentioned.

Accordingly, preferred anions X ⁻ in the general formula (6) include trifluoromethanesulfonate anion, perfluoro-n-butanesulfonate anion, perfluoro-n-octanesulfonate anion, 2-bicyclo [2.2.1] hepta. 2-yl-1,1,2,2-tetrafluoroethanesulfonate anion, 2-bicyclo [2.2.1] hept-2-yl-1,1-difluoroethanesulfonate anion, the following formula (8-1) Examples include anions represented by (8-7).

  Specific examples of the general formula (6) include triphenylsulfonium trifluoromethanesulfonate, tri-tert-butylphenylsulfonium trifluoromethanesulfonate, 4-cyclohexylphenyl-diphenylsulfonium trifluoromethanesulfonate, 4-methanesulfonylphenyl-diphenyl. Sulfonium trifluoromethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-n-butoxynaphthyl) tetrahydrothiophenium trifluoromethanesulfonate,

  Triphenylsulfonium perfluoro-n-butanesulfonate, tri-tert-butylphenylsulfonium perfluoro-n-butanesulfonate, 4-cyclohexylphenyl-diphenylsulfonium perfluoro-n-butanesulfonate, 4-methanesulfonylphenyl-diphenylsulfonium per Fluoro-n-butanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium perfluoro-n-butanesulfonate, 1- (4-n-butoxynaphthyl) tetrahydrothiophenium perfluoro- n-butanesulfonate,

  Triphenylsulfonium perfluoro-n-octane sulfonate, tri-tert-butylphenylsulfonium perfluoro-n-octane sulfonate, 4-cyclohexylphenyl-diphenylsulfonium perfluoro-n-octane sulfonate, 4-methanesulfonylphenyl-diphenylsulfonium per Fluoro-n-octanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (4-n-butoxynaphthyl) tetrahydrothiophenium perfluoro- n-octane sulfonate,

  Triphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1,2,2-tetrafluoroethanesulfonate, tri-tert-butylphenylsulfonium 2- (bicyclo [2.2 .1] Hepta-2'-yl) -1,1,2,2-tetrafluoroethanesulfonate, 4-cyclohexylphenyl-diphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl)- 1,1,2,2-tetrafluoroethanesulfonate, 4-methanesulfonylphenyl-diphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1,2,2-tetrafluoro Ethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium 2- (bicyclo [2.2. ] Hepta-2'-yl) -1,1,2,2-tetrafluoroethanesulfonate, 1- (4-n-butoxynaphthyl) tetrahydrothiophenium 2- (bicyclo [2.2.1] hepta-2 '-Yl) -1,1,2,2-tetrafluoroethanesulfonate,

  Triphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1-difluoroethanesulfonate, tri-tert-butylphenylsulfonium 2- (bicyclo [2.2.1] hepta-2 '-Yl) -1,1-difluoroethanesulfonate, 4-cyclohexylphenyl-diphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1-difluoroethanesulfonate, 4-methanesulfonylphenyl -Diphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1-difluoroethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium 2- ( Bicyclo [2.2.1] hepta-2'-yl) -1,1-difluoroeta Sulfonate, 1- (4-n-butoxynaphthyl) tetrahydrothiophenium 2- (bicyclo [2.2.1] hepta-2′-yl) -1,1-difluoroethanesulfonate, represented by the following formulas C1 to C15 And the like.

  In addition, in this invention, the acid generator 1 can be used individually or in mixture of 2 or more types.

  Examples of the radiation sensitive acid generator other than the acid generator 1 that can be used as a radiation sensitive acid generator (hereinafter referred to as “other acid generator”) include, for example, onium salt compounds, A halogen-containing compound, a diazoketone compound, a sulfone compound, a sulfonic acid compound, and the like can be given. Examples of these other acid generators include the following.

Onium salt compounds:
Examples of the onium salt compound include iodonium salts, sulfonium salts, phosphonium salts, diazonium salts, pyridinium salts, and the like.
Specific examples of the onium salt compound include diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium perfluoro-n-octanesulfonate, diphenyliodonium 2-bicyclo [2.2.1] hepta-2. -Yl-1,1,2,2-tetrafluoroethanesulfonate, bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis ( 4-t-butylphenyl) iodonium perfluoro-n-octanesulfonate, bis (4-t-butylphenyl) iodonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2- Te La tetrafluoroethane sulfonate, cyclohexyl 2-oxo-cyclohexyl methyl trifluoromethanesulfonate, dicyclohexyl-2-oxo-cyclohexyl trifluoromethane sulfonate, and 2-oxo-cyclohexyl dimethyl sulfonium trifluoromethanesulfonate, and the like.

Halogen-containing compounds:
Examples of the halogen-containing compound include a haloalkyl group-containing hydrocarbon compound and a haloalkyl group-containing heterocyclic compound.
Specific examples of halogen-containing compounds include (trichloromethyl such as phenylbis (trichloromethyl) -s-triazine, 4-methoxyphenylbis (trichloromethyl) -s-triazine, 1-naphthylbis (trichloromethyl) -s-triazine. ) -S-triazine derivatives and 1,1-bis (4-chlorophenyl) -2,2,2-trichloroethane.

Diazo ketone compounds:
Examples of the diazo ketone compound include a 1,3-diketo-2-diazo compound, a diazobenzoquinone compound, a diazonaphthoquinone compound, and the like.
Specific examples of the diazo ketone include 1,2-naphthoquinonediazide-4-sulfonyl chloride, 1,2-naphthoquinonediazide-5-sulfonyl chloride, 1,2, naphthoquinonediazide of 2,3,4,4′-tetrahydroxybenzophenone. -4-sulfonic acid ester or 1,2-naphthoquinonediazide-5-sulfonic acid ester, 1,1,1-naphthoquinonediazide-4-sulfonic acid ester of 1,1,1-tris (4-hydroxyphenyl) ethane Examples include 2-naphthoquinonediazide-5-sulfonic acid ester.

Sulfone compounds:
Examples of the sulfone compound include β-ketosulfone, β-sulfonylsulfone, and α-diazo compounds of these compounds.
Specific examples of the sulfone compound include 4-trisphenacylsulfone, mesitylphenacylsulfone, bis (phenylsulfonyl) methane, and the like.

Sulfonic acid compounds:
Examples of the sulfonic acid compounds include alkyl sulfonic acid esters, alkyl sulfonic acid imides, haloalkyl sulfonic acid esters, aryl sulfonic acid esters, and imino sulfonates.
Specific examples of the sulfonic acid compound include benzoin tosylate, pyrogallol tris (trifluoromethanesulfonate), nitrobenzyl-9,10-diethoxyanthracene-2-sulfonate, trifluoromethanesulfonylbicyclo [2.2.1] hept- 5-ene-2,3-dicarbodiimide, nonafluoro-n-butanesulfonylbicyclo [2.2.1] hept-5-ene-2,3-dicarbodiimide, perfluoro-n-octanesulfonylbicyclo [2.2 .1] Hept-5-ene-2,3-dicarbodiimide, 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonylbicyclo [2.2. 1] Hept-5-ene-2,3-dicarbodiimide, N- (trifluoromethanesulfonyl Xyl) succinimide, N- (nonafluoro-n-butanesulfonyloxy) succinimide, N- (perfluoro-n-octanesulfonyloxy) succinimide, N- (2-bicyclo [2.2.1] hept-2-yl- 1,1,2,2-tetrafluoroethanesulfonyloxy) succinimide, 1,8-naphthalenedicarboxylic imide trifluoromethanesulfonate, 1,8-naphthalenedicarboxylic imidononafluoro-n-butanesulfonate, 1,8-naphthalenedicarboxylic Examples include acid imido perfluoro-n-octane sulfonate.

  Among these other acid generators, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium perfluoro-n-octanesulfonate, diphenyliodonium 2-bicyclo [2.2.1] hepta- 2-yl-1,1,2,2-tetrafluoroethanesulfonate, bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis (4-t-Butylphenyl) iodonium perfluoro-n-octanesulfonate, bis (4-t-butylphenyl) iodonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2 -Tetraph Oro ethanesulfonate, cyclohexyl 2-oxo-cyclohexyl methyl trifluoromethanesulfonate, dicyclohexyl-2-oxo-cyclohexyl trifluoromethane sulfonate, 2-oxo-cyclohexyl dimethyl sulfonium trifluoromethane sulfonate,

Trifluoromethanesulfonylbicyclo [2.2.1] hept-5-ene-2,3-dicarbodiimide, nonafluoro-n-butanesulfonylbicyclo [2.2.1] hept-5-ene-2,3-dicarbodiimide Perfluoro-n-octanesulfonylbicyclo [2.2.1] hept-5-ene-2,3-dicarbodiimide, 2-bicyclo [2.2.1] hept-2-yl-1,1,2 , 2-tetrafluoroethanesulfonylbicyclo [2.2.1] hept-5-ene-2,3-dicarbodiimide, N- (trifluoromethanesulfonyloxy) succinimide, N- (nonafluoro-n-butanesulfonyloxy) succinimide N- (perfluoro-n-octanesulfonyloxy) succinimide, N- (2-bicyclo [2.2 1] hept-2-yl-1,1,2,2-tetrafluoroethane sulfonyloxy) succinimide, 1,8-naphthalenedicarboxylic acid imide trifluoromethanesulfonate and the like are preferable.
The other acid generators can be used alone or in admixture of two or more.

In this invention, the total usage-amount of the acid generator 1 and another acid generator is 0.1 to 100 mass parts of resin (A) normally from a viewpoint of ensuring the sensitivity and developability as a resist. 20 parts by mass, preferably 0.5 to 10 parts by mass. When the total amount used is less than 0.1 parts by mass, the sensitivity and developability tend to decrease. On the other hand, when it exceeds 20 parts by mass, the transparency to radiation is lowered, and it tends to be difficult to obtain a rectangular resist pattern.
Moreover, the usage-amount of other acid generators is 80 mass% or less normally with respect to 100 mass% of the sum total of the acid generator 1 and another acid generator, Preferably it is 60 mass% or less.

<Additives>
In the resin composition for forming the second resist layer of the present invention, various additives such as an acid diffusion controller, an alicyclic additive, a surfactant, and a sensitizer can be blended as necessary. .

  The acid diffusion control agent is a component having an action of controlling a diffusion phenomenon of an acid generated from an acid generator upon exposure in a resist film and suppressing an undesirable chemical reaction in a non-exposed region. By mix | blending such an acid diffusion control agent, the storage stability of the resin composition for 2nd resist layer formation obtained 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. A thing is obtained.

Examples of the acid diffusion controller include tertiary amine compounds, other amine compounds, amide group-containing compounds, urea compounds, and other nitrogen-containing heterocyclic compounds.
Examples of the tertiary amine compounds include mono (cyclo) alkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, cyclohexylamine; di-n-butylamine Di-n-pentylamine, di-n-hexylamine, di-n-heptylamine, di-n-octylamine, di-n-nonylamine, di-n-decylamine, cyclohexylmethylamine, dicyclohexylamine, etc. (Cyclo) alkylamines; triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octylamine, Tri-n-nonylamine, tri-n-decylamine, cyclohex Tri (cyclo) alkylamines such as dimethylamine, methyldicyclohexylamine, tricyclohexylamine; substituted alkylamines such as 2,2 ′, 2 ″ -nitrotriethanol; aniline, N-methylaniline, N, N— Dimethylaniline, 2-methylaniline, 3-methylaniline, 4-methylaniline, 4-nitroaniline, diphenylamine, triphenylamine, naphthylamine, 2,4,6-tri-tert-butyl-N-methylaniline, N- Phenyldiethanolamine, 2,6-diisopropylaniline and the like are preferable.

  Examples of the other amine compounds include ethylenediamine, N, N, N ′, N′-tetramethylethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether, 4,4′-diaminobenzophenone, 4,4′-diaminodiphenylamine, 2,2-bis (4-aminophenyl) propane, 2- (3-aminophenyl) -2- (4-aminophenyl) propane, 2- (4-aminophenyl) -2- (3-hydroxyphenyl) propane, 2- (4-aminophenyl) -2- (4-hydroxyphenyl) propane, 1,4-bis [1- (4-aminophenyl) -1-methylethyl] benzene, 1,3-bis [1- (4-aminophenyl) -1-methyl ester Benzene], bis (2-dimethylaminoethyl) ether, bis (2-diethylaminoethyl) ether, 1- (2-hydroxyethyl) -2-imidazolidinone, 2-quinoxalinol, N, N, N ′ , N′-tetrakis (2-hydroxypropyl) ethylenediamine, N, N, N ′, N ″, N ″ -pentamethyldiethylenetriamine and the like are preferable.

  Examples of the amide group-containing compound include Nt-butoxycarbonyldi-n-octylamine, Nt-butoxycarbonyldi-n-nonylamine, Nt-butoxycarbonyldi-n-decylamine, Nt -Butoxycarbonyldicyclohexylamine, Nt-butoxycarbonyl-1-adamantylamine, Nt-butoxycarbonyl-2-adamantylamine, Nt-butoxycarbonyl-N-methyl-1-adamantylamine, (S)- (-)-1- (t-butoxycarbonyl) -2-pyrrolidinemethanol, (R)-(+)-1- (t-butoxycarbonyl) -2-pyrrolidinemethanol, Nt-butoxycarbonyl-4-hydroxy Piperidine, Nt-butoxycarbonylpyrrolidine, Nt-butoxycarbo Lupiperazine, Nt-butoxycarbonylpiperidine, N, N-di-t-butoxycarbonyl-1-adamantylamine, N, N-di-t-butoxycarbonyl-N-methyl-1-adamantylamine, Nt- Butoxycarbonyl-4,4'-diaminodiphenylmethane, N, N'-di-t-butoxycarbonylhexamethylenediamine, N, N, N'N'-tetra-t-butoxycarbonylhexamethylenediamine, N, N'- Di-t-butoxycarbonyl-1,7-diaminoheptane, N, N′-di-t-butoxycarbonyl-1,8-diaminooctane, N, N′-di-t-butoxycarbonyl-1,9-diaminononane N, N′-di-t-butoxycarbonyl-1,10-diaminodecane, N, N′-di-t-butoxycal Nyl-1,12-diaminododecane, N, N′-di-t-butoxycarbonyl-4,4′-diaminodiphenylmethane, Nt-butoxycarbonylbenzimidazole, Nt-butoxycarbonyl-2-methylbenzimidazole Nt-butoxycarbonyl group-containing amino compounds such as Nt-butoxycarbonyl-2-phenylbenzimidazole, formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N , N-dimethylacetamide, propionamide, benzamide, pyrrolidone, N-methylpyrrolidone, N-acetyl-1-adamantylamine, isocyanuric acid tris (2-hydroxyethyl) and the like are preferable.

  Examples of the urea compound include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, tri-n-butyl. Thiourea and the like are preferable.

  Examples of the other nitrogen-containing heterocyclic compounds include imidazole, 4-methylimidazole, 4-methyl-2-phenylimidazole, benzimidazole, 2-phenylbenzimidazole, 1-benzyl-2-methylimidazole, 1-benzyl- Imidazoles such as 2-methyl-1H-imidazole; pyridine, 2-methylpyridine, 4-methylpyridine, 2-ethylpyridine, 4-ethylpyridine, 2-phenylpyridine, 4-phenylpyridine, 2-methyl-4- Pyridines such as phenylpyridine, nicotine, nicotinic acid, nicotinamide, quinoline, 4-hydroxyquinoline, 8-oxyquinoline, acridine, 2,2 ′: 6 ′, 2 ″ -terpyridine; piperazine, 1- (2 Piperazine such as -hydroxyethyl) piperazine In addition, pyrazine, pyrazole, pyridazine, quinosaline, purine, pyrrolidine, piperidine, piperidine ethanol, 3-piperidino-1,2-propanediol, morpholine, 4-methylmorpholine, 1- (4-morpholinyl) ethanol, 4-acetyl Preferred are morpholine, 3- (N-morpholino) -1,2-propanediol, 1,4-dimethylpiperazine, 1,4-diazabicyclo [2.2.2] octane and the like.

These acid diffusion control agents can be used alone or in admixture of two or more.
Further, the blending amount of the acid diffusion controller is preferably 0.001 to 15 parts by mass, more preferably 0.01 to 10 parts by mass, and still more preferably 0 to 100 parts by mass of the resin (A). 0.05 to 5 parts by mass. When the compounding amount of the acid diffusion controller exceeds 15 parts by mass, the sensitivity as a resist may decrease. On the other hand, when the amount is less than 0.001 part by mass, the pattern shape and dimensional fidelity as a resist may be lowered depending on the process conditions.

The alicyclic additive is a component having an action of further improving dry etching resistance, pattern shape, adhesion to a substrate, and the like.
Examples of such alicyclic additives include 1-adamantanecarboxylic acid, 2-adamantanone, 1-adamantanecarboxylic acid t-butyl, 1-adamantanecarboxylic acid t-butoxycarbonylmethyl, 1-adamantanecarboxylic acid α. -Butyrolactone ester, 1,3-adamantane dicarboxylic acid di-t-butyl, 1-adamantane acetate t-butyl, 1-adamantane acetate t-butoxycarbonylmethyl, 1,3-adamantane diacetate di-t-butyl, 2, Adamantane derivatives such as 5-dimethyl-2,5-di (adamantylcarbonyloxy) hexane; t-butyl deoxycholic acid, t-butoxycarbonylmethyl deoxycholic acid, 2-ethoxyethyl deoxycholic acid, 2-deoxycholic acid 2- Cyclohexyloxyethyl, deoxy Deoxycholic acid esters such as 3-oxocyclohexyl cholic acid, tetrahydropyranyl deoxycholic acid, mevalonolactone ester of deoxycholic acid; t-butyl lithocholic acid, tert-butoxycarbonylmethyl lithocholic acid, 2-ethoxyethyl lithocholic acid, Lithocholic acid esters such as lithocholic acid 2-cyclohexyloxyethyl, lithocholic acid 3-oxocyclohexyl, lithocholic acid tetrahydropyranyl, lithocholic acid mevalonolactone ester; dimethyl adipate, diethyl adipate, dipropyl adipate, din adipate - butyl, alkyl carboxylic acid esters such as adipate t- butyl or 3- [2-hydroxy-2,2-bis (trifluoromethyl) ethyl] tetracyclo [4.4.0.1 ^{2, 5} 1 ^7,10 ] dodecane and the like. These alicyclic additives can be used alone or in admixture of two or more.

The surfactant is a component having an action of improving coating properties, striation, developability and the like.
Examples of such surfactants include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, and polyethylene glycol dilaurate. In addition to nonionic surfactants such as polyethylene glycol distearate, KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, no. 95 (manufactured by Kyoeisha Chemical Co., Ltd.), F-top EF301, EF303, EF352 (manufactured by Tochem Products Co., Ltd.), Megafax F171, F173 (manufactured by Dainippon Ink & Chemicals, Inc.), Florard FC430, FC431 ( Sumitomo 3M Limited), Asahi Guard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-105, SC-106 (Asahi Glass Co., Ltd.) And the like. These surfactants can be used alone or in admixture of two or more.

The sensitizer absorbs radiation energy and transmits the energy to the acid generator, thereby increasing the amount of acid generated, thereby improving the apparent sensitivity of the resin composition. Has the effect of
Examples of such sensitizers include carbazoles, acetophenones, benzophenones, naphthalenes, phenols, biacetyl, eosin, rose bengal, pyrenes, anthracenes, phenothiazines, and the like. These sensitizers can be used alone or in admixture of two or more.

  Furthermore, examples of additives other than the above include alkali-soluble resins, low-molecular alkali-solubility control agents having acid-dissociable protecting groups, antihalation agents, storage stabilizers, antifoaming agents, and the like. In addition, by blending a dye or pigment, the latent image of the exposed area can be visualized, and the influence of halation during exposure can be alleviated, and by blending an adhesion aid, adhesion to the substrate can be improved. it can.

[3] Positive-type radiation-sensitive resin composition for forming the first resist layer The first resist layer-forming resin composition used when forming the first resist layer in the resist pattern forming method described above is an action of acid. It is the resin composition containing resin (a) which becomes alkali-soluble by solvent and solvent (b).

<Resin (a) that becomes alkali-soluble by the action of acid>
The resin (a) (hereinafter referred to as “resin (a)”) that becomes alkali-soluble by the action of an acid is an alkali-insoluble or alkali-insoluble resin that becomes alkali-soluble by the action of an acid. The term “alkali-insoluble or alkali-insoluble” as used herein refers to alkali development conditions employed when a resist pattern is formed from a resist film formed from the resin composition for forming a first resist layer containing the resin (a). Below, when the film which uses only resin (a) instead of this resist film is developed, it means the property that 50% or more of the initial film thickness of this film remains after development.

  The resin (a) is not particularly limited as long as it becomes alkali-soluble by the action of an acid. For example, the resin (a) contains a skeleton that is alkali-soluble by the action of an acid, which is represented by the repeating unit (2). What contains a repeating unit and the repeating unit containing the lactone skeleton represented by the above-mentioned repeating unit (3) is preferable. In this case, the resin (or resist film) is preferable in that it is difficult to dissolve in the alcohol solvent.

In addition to the repeating unit (2) and the repeating unit (3), the resin (a) may contain other repeating units.
Examples of the other repeating units include other repeating units such as the repeating units (4) and (5) in the above-described resin composition for forming a second resist layer.

  Furthermore, the resin (a) may contain a repeating unit represented by the following general formula (9) (hereinafter, also referred to as “repeating unit (6)”) as another repeating unit.

〔一般式（９）において、Ｒ^１６は水素原子、炭素数１〜４のアルキル基、トリフルオロメチル基、又はヒドロキシメチル基を示し、Ｒ^１７は２価の有機基を示す。〕

[In General Formula (9), R ¹⁶ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a trifluoromethyl group, or a hydroxymethyl group, and R ¹⁷ represents a divalent organic group. ]

Examples of the alkyl group having 1 to 4 carbon atoms in R ¹⁶ of the repeating unit (6) include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a 2-methylpropyl group, 1 Examples thereof include alkyl groups such as -methylpropyl group and t-butyl group.

The divalent organic group in R ¹⁷ of the repeating unit (6) is preferably a divalent hydrocarbon group, and a chain or cyclic hydrocarbon group is preferable among the divalent hydrocarbon groups. It may be an alkylene glycol group, an alkylene ester group or the like.
Specifically, methylene group, ethylene group, propylene group such as 1,3-propylene group or 1,2-propylene group, tetramethylene group, pentamethylene group, hexamethylene group, heptamethylene group, octamethylene group, nonamethylene Group, decamethylene group, undecamethylene group, dodecamethylene group, tridecamethylene group, tetradecamethylene group, pentadecamethylene group, hexadecamethylene group, heptacamethylene group, octadecamethylene group, nonacamethylene group, insalen Group, 1-methyl-1,3-propylene group, 2-methyl-1,3-propylene group, 2-methyl-1,2-propylene group, 1-methyl-1,4-butylene group, 2-methyl-1 , 4-butylene group, methylidene group, ethylidene group, propylidene group, 2-propylidene group, etc. Hydrogen radical;

Cyclobutylene groups such as 1,3-cyclobutylene groups, cyclopentylene groups such as 1,3-cyclopentylene groups, cyclohexylene groups such as 1,4-cyclohexylene groups, 1,5-cyclooctylene groups, etc. A monocyclic hydrocarbon ring group such as a cycloalkylene group having 3 to 10 carbon atoms such as a cyclooctylene group; a norbornylene group such as a 1,4-norbornylene group or a 2,5-norbornylene group; 1,5-adamantylene And a crosslinked cyclic hydrocarbon ring group such as a 2- to 4-cyclic hydrocarbon ring group having 4 to 30 carbon atoms such as an adamantylene group such as a 2,6-adamantylene group. Among these, R ¹⁷ is preferably a hydrocarbon group containing a 2,5-norbornylene group, a 1,2-ethylene group, or a propylene group.

When R ¹⁷ contains a divalent aliphatic cyclic hydrocarbon group, a bistrifluoromethyl-hydroxy-methyl group [—C (CF ₃ ) ₂ OH], a divalent aliphatic cyclic hydrocarbon group, It is preferable to arrange | position a C1-C4 alkylene group as a spacer between these.

As the monomer that gives the repeating unit (6), (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 and the like are preferable.

  Moreover, the said resin (a) may contain the at least 1 sort (s) of repeating unit among following formula (10-1)-(10-8) as another repeating unit.

〔式（１０−１）〜（１０−８）において、Ｒ^１８は水素原子、メチル基又はトリフルオロメチル基を示す。〕

[In the formulas (10-1) to (10-8), R ¹⁸ represents a hydrogen atom, a methyl group or a trifluoromethyl group. ]

  The resin (a) may contain only one kind of these other repeating units, or may contain two or more kinds.

  The content of the repeating unit (2) in the resin (a) of the resin composition for forming a first resist layer is 10 to 10% when the total of all the repeating units contained in the resin (a) is 100 mol%. It is preferable that it is 70 mol%, More preferably, it is 10-60 mol%, More preferably, it is 20-60 mol%. When the content rate of this repeating unit (2) is less than 10 mol%, there exists a possibility that the resolution as a resist film may deteriorate. On the other hand, when it exceeds 70 mol%, the developability of the resist film may be deteriorated.

  The content of the repeating unit (3) is preferably 10 to 70 mol%, more preferably 10 to 60 mol, when the total of all repeating units contained in the resin (a) is 100 mol%. It is mol%, More preferably, it is 10-50 mol%. When the content of the repeating unit (3) is less than 10 mol%, the developability of the resist film may be lowered. On the other hand, when it exceeds 70 mol%, the resolution may be lowered, or the solubility in a resist solvent may be lowered.

  The content of the repeating unit (4) is preferably 30 mol% or less, more preferably 25 mol% or less, when the total of all repeating units contained in the resin (a) is 100 mol%. It is. When the content rate of this repeating unit (4) exceeds 30 mol%, there exists a possibility that the resist film obtained may become easy to swell with an alkali developing solution, or the solubility with respect to an alkaline developing solution may fall.

  The content of the repeating unit (5) is preferably 30 mol% or less, more preferably 25 mol% or less, when the total of all repeating units contained in the resin (a) is 100 mol%. It is. When the content rate of this repeating unit (5) exceeds 30 mol%, the obtained resist film may be easily swollen by the alkali developer, or the solubility in the alkali developer may be reduced.

  The content of the repeating unit (6) is preferably 30 mol% or less, more preferably 25 mol% or less, when the total of all the repeating units contained in the resin (a) is 100 mol%. It is. When the content rate of this repeating unit (1) exceeds 30 mol%, the top loss of a resist pattern will arise and there exists a possibility that a pattern shape may deteriorate.

  Further, the content of other repeating units [total of repeating units other than the repeating units (2) and (3)] is preferably 50 mol% or less with respect to all the repeating units in the resin (a). More preferably, it is 40 mol% or less.

  In addition, the resin composition for 1st resist layer formation may contain 1 type of resin (a), and may contain 2 or more types.

This resin (a) can be prepared in the same manner as the above-mentioned resin (A) using, for example, a polymerizable unsaturated monomer for constituting each of the above-mentioned repeating units.
The molecular weight of the resin (a) is not particularly limited, but the polystyrene-equivalent weight average molecular weight (hereinafter also referred to as “Mw”) by gel permeation chromatography (GPC) is preferably 1000 to 100,000, and more preferably. Is 1000-30000, more preferably 1000-20000. If the Mw of the resin (a) is less than 1000, when the resist film is formed, the heat resistance may be lowered. On the other hand, if this Mw exceeds 100,000, the developability may be lowered when a resist film is formed. Furthermore, the ratio (Mw / Mn) between the Mw of the resin (a) and the polystyrene-equivalent number average molecular weight (hereinafter also referred to as “Mn”) by gel permeation chromatography (GPC) is usually 1 to 5, preferably Is 1-3.

  Moreover, also in resin (a), the low molecular weight component derived from the monomer used when preparing resin may be contained. The content of the low molecular weight component is preferably 0.1% by mass or less, more preferably 0.07% by mass or less, further preferably 100% by mass (in terms of solid content) of the resin (a). It is 0.05 mass% or less. When this content is 0.1% by mass or less, no foreign matter is generated in the resist when the resist is stored, and there is no coating unevenness even when the resist is applied. It can be sufficiently suppressed. Furthermore, when the exposure is performed by the immersion exposure method, it is possible to reduce the amount of the eluate in the immersion exposure liquid such as water that is in contact with the exposure.

Further, the resin (a) is preferably one having few impurities such as halogen and metal, and by reducing such impurities, the sensitivity, resolution, process stability, pattern shape, etc. of the resist film to be formed are reduced. Further improvements can be made.
Examples of the purification method of the resin (a) include the same methods as described above.

<Solvent (b)>
Examples of the solvent (b) contained in the first resist layer forming resin composition include 2-butanone, 2-pentanone, 3-methyl-2-butanone, 2-hexanone, and 4-methyl-2- Linear or branched ketones such as pentanone, 3-methyl-2-pentanone, 3,3-dimethyl-2-butanone, 2-heptanone, 2-octanone; cyclopentanone, 3-methylcyclopentanone, Cyclic ketones such as cyclohexanone, 2-methylcyclohexanone, 2,6-dimethylcyclohexanone, isophorone; propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol mono-n-propyl ether acetate, propylene glycol mono-i -Propyl ether ace Propylene glycol mono-n-butyl ether acetate, propylene glycol mono-i-butyl ether acetate, propylene glycol mono-sec-butyl ether acetate, propylene glycol monoalkyl ether acetates such as propylene glycol mono-t-butyl ether acetate; 2- Methyl hydroxypropionate, ethyl 2-hydroxypropionate, n-propyl 2-hydroxypropionate, i-propyl 2-hydroxypropionate, n-butyl 2-hydroxypropionate, i-butyl 2-hydroxypropionate, 2- Alkyl 2-hydroxypropionates such as sec-butyl hydroxypropionate and t-butyl 2-hydroxypropionate; methyl 3-methoxypropionate Methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate and the like of 3-alkoxy propionic acid alkyl ethers other,

  Toluene, xylene, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutyrate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3 -Methyl-3-methoxybutyl propionate, 3-methyl-3-methoxybutyl butyrate, 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 ethyl ether, di-n-hexyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, caproic acid, caprylic acid, 1-o Pentanol, 1-nonanol, benzyl alcohol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, .gamma.-butyrolactone, ethylene carbonate, and propylene carbonate.

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. .
These solvent (b) can be used individually or in mixture of 2 or more types.

  Moreover, the resin composition for forming the first resist layer is usually used in the solvent (b) so that the total solid content concentration is usually 1 to 50% by mass, preferably 1 to 25% by mass, when used. After dissolution, it is prepared, for example, by filtering with a filter having a pore size of about 0.2 μm.

<Radiosensitive acid generator>
The resin composition for forming the first resist layer is usually mixed with a radiation sensitive acid generator.
As the acid generator, the description of the acid generator in the second resist layer forming resin composition can be applied as it is. The acid generator blended in the first resist layer forming resin composition and the acid generator blended in the second resist layer forming resin composition may be the same or different. Good.
The total amount of the acid generator 1 and the other acid generator used is usually 0.1 to 100 parts by mass of the resin (a) from the viewpoint of ensuring sensitivity and developability as a resist. 20 parts by mass, preferably 0.5 to 10 parts by mass. When the total amount used is less than 0.1 parts by mass, the sensitivity and developability tend to decrease. On the other hand, when it exceeds 20 parts by mass, the transparency to radiation is lowered, and it tends to be difficult to obtain a rectangular resist pattern.
Moreover, the usage-amount of other acid generators is 80 mass% or less normally with respect to 100 mass% of the sum total of the acid generator 1 and another acid generator, Preferably it is 60 mass% or less.

<Additives>
Moreover, an additive can be mix | blended with this resin composition for 1st resist layer formation. In addition, as this additive, description of various additives, such as the said acid diffusion control agent in the above-mentioned resin composition for 2nd resist layer formation, can be applied as it is.
In addition, it is preferable that the compounding quantity at the time of mix | blending an acid diffusion control agent is 0.001-15 mass parts with respect to 100 mass parts of resin (a), More preferably, 0.01-10 mass, Furthermore, Preferably it is 0.05-5 mass parts. When the compounding amount of the acid diffusion controller exceeds 15 parts by mass, the sensitivity as a resist may decrease. On the other hand, when the amount is less than 0.001 part by mass, the pattern shape and dimensional fidelity as a resist may be lowered depending on the process conditions.

  Hereinafter, the embodiment of the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. Here, the part is based on mass unless otherwise specified.

<Synthesis of Resins (A-1) and (X-1)>
Hereinafter, a synthesis example of each resin will be described. In addition, each measurement and evaluation in each following synthesis example were performed in the following way.

(1) Mw and Mn
Tosoh Co., Ltd. high-speed GPC device (model “HLC-8120”), Tosoh Co., Ltd. GPC column (trade name “G2000HXL”; 2, “G3000HXL”; 1, “G400HXL”; 1) Was measured by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard under the analysis conditions of a flow rate of 1.0 ml / min, elution solvent tetrahydrofuran, and column temperature of 40 ° C. Further, the degree of dispersion Mw / Mn was calculated from the measurement results.
⁽²⁾ 13 C-NMR analysis of ¹³ C-NMR analysis the polymer, using a Nippon Denshi Co. "JNM-EX270", was measured.

  Moreover, each monomer used for the synthesis | combination of resin (A-1) and resin (X-1) is shown below as a formula (M-1)-(M-5).

<Synthesis of Resin (A-1)>
A monomer obtained by previously adding 41.09 g of the monomer (M-1) and 8.91 g of the monomer (M-2) in 100 g of methyl ethyl ketone and adding 2.14 g of azobisisobutyronitrile. A meter solution was prepared. On the other hand, 50 g of methyl ethyl ketone was put into a 500 ml three-necked flask equipped with a thermometer and a dropping funnel, and the flask was heated to 80 ° C. while stirring with a magnetic stirrer. Using a dropping funnel and an auto feeder, a monomer solution prepared in advance was added dropwise over 3 hours while heating and refluxing at 80 ° C. After completion of the dropping, the mixture was further refluxed at 80 ° C. for 3 hours, and cooled to 30 ° C. or lower after the reaction to obtain a copolymer solution.

  200 g of the copolymer solution was transferred to a separatory funnel, and 150 g of methanol and 800 g of n-hexane were added to the separatory funnel for separation and purification. The obtained lower layer liquid was recovered, methanol was further added to adjust the total amount to 150 g, and the mixture was again put into a separatory funnel. Further, 800 g of n-hexane was added, and liquid separation purification was performed again, and the lower layer was recovered after separation. The recovered lower layer solution was replaced with 4-methyl-2-pentanol. The solid content concentration of the sample after solvent replacement was calculated from the mass of the residue after placing 0.3 g of the resin solution on an aluminum pan and heating on a hot plate heated to 150 ° C. for 1 hour. Used for adjustment and yield calculation. The obtained copolymer had Mw = 12,062, Mw / Mn = 1.351, and the yield was 32%. This polymer is referred to as “resin (A-1)”.

  The resin (A-1) is a resin that is soluble in a solvent that does not dissolve the existing resist resin (for example, an alcohol solvent) and is soluble in the developer after forming the resist pattern.

<Synthesis of Resin (X-1)>
Monomer (M-3) 53.93 g (50 mol%), monomer (M-4) 35.38 g (40 mol%), and monomer (M-5) 10.69 g (10 mol) %) Was dissolved in 200 g of 2-butanone, and a monomer solution containing 5.58 g of dimethyl 2,2′-azobis (2-methylpropionate) was prepared, and 100 g of 2-butanone was added. A 500 ml three-necked flask was purged with nitrogen for 30 minutes. After the nitrogen purge, the reaction kettle was heated to 80 ° C. with stirring, and the monomer solution prepared in advance was added dropwise over 3 hours using a dropping funnel. The polymerization start was carried out for 6 hours with the start of dropping as the polymerization start time. After completion of the polymerization, the polymerization solution was cooled with water to 30 ° C. or lower, poured into 2000 g of methanol, and the precipitated white powder was separated by filtration. The filtered white powder was washed twice with 400 g of methanol on the slurry, filtered, and dried at 50 ° C. for 17 hours to obtain a white powder polymer (74 g, yield 74%). .
This polymer has Mw of 6900, Mw / Mn = 1.70, 13C-NMR analysis results, each repeating unit derived from monomers (M-3), (M-4), and (M-5) Was a copolymer having a content of 53.0: 37.2: 9.8 (mol%). This polymer is referred to as “resin (X-1)”. In addition, content of the low molecular-weight component derived from each monomer in resin (X-1) was 0.03 mass% with respect to 100 mass% of this polymer.

<Preparation of radiation sensitive resin composition (resin composition for forming second resist layer)>
Resins, solvents, acid generators and acid diffusion control agents were mixed at the ratios shown in Table 1 to prepare resin compositions (I) to (II). Moreover, resin and a solvent were mixed and resin solution (I) was prepared.

Details of the solvent, acid generator, and acid diffusion controller shown in Table 1 are shown below. In the table, “part” is based on mass unless otherwise specified.
[solvent]
(B-1): 4-methyl-2-pentanol (B-2): γ-butyrolactone (B-3): propylene glycol monomethyl ether acetate [acid generator]
(C-1): 1- (4-n-butoxynaphthyl) tetrahydrothiophenium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1,2,2-tetrafluoroethane Sulfonate [Acid Diffusion Control Agent]
(D-1): Nt-butoxycarbonyl-4-hydroxypiperidine

<Evaluation of resin composition>
Examples 1-2 and Comparative Examples 1-2
Using the resin compositions (I) and (II), patterning was performed as follows, and the following various evaluations were performed. These evaluation results are shown in Table 2.

Using the resin compositions (I) and (II), patterning was performed on each of the following substrates (A) and (B) on which various underlayer films were formed on an 8-inch silicon wafer.
Substrate (A): On an 8-inch silicon wafer, “CLEAN TRACK ACT8” (manufactured by Tokyo Electron Co., Ltd.) is used to spin coat the lower antireflection film “ARC29A” (manufactured by Brewer Science Co., Ltd.) at 205 ° C. for 60 seconds. PB was performed under the conditions of the above, and a film having a film thickness of 77 nm was formed. Substrate (B); On the lower antireflection film of the substrate (A), the resin solution (I) was applied by CLEAN TRACK ACT8, PB was performed at 100 ° C. for 60 seconds to form a 120 nm thick coating film

  Specifically, each of the resin compositions was spin-coated on each of the substrates, and PB was performed at 110 ° C. for 60 seconds to form a resist layer having a thickness of 120 nm. Next, exposure is performed with an ArF projection exposure apparatus S306C (manufactured by Nikon Corporation) under optical conditions of NA: 0.78, sigma: 0.85, 2/3 Ann, and firing on a CLEAN TRACK ACT8 hot plate (hereinafter referred to as “PEB” (PEB condition: 110 ° C., 60 seconds), paddle development (30 seconds) with the LD nozzle of the same CLEAN TRACK ACT8, rinsing with ultrapure water, and spin drying by shaking off at 4000 rpm for 15 seconds.

  Thereafter, each substrate is exposed to a scanning electron microscope (manufactured by Hitachi Keiki Co., Ltd., “S9260A”) in a 90 nm line and space (1L1S) pattern to form a one-to-one line width of 90 nm. Was the optimum exposure.

<Applicability>
Regarding the coating property, when the resin composition (I) or (II) is applied onto the substrate (A) or (B) by spin coating, “○” indicates that the coating film is uniformly formed. No film was formed and evaluated as “x”.

<Pattern forming ability>
The pattern forming ability was evaluated as “x” when the substrate (A) or (B) on which the pattern of the resist alone could be formed was not “◯”.

<Pattern shape>
Regarding the pattern shape, when the cross-sectional shape of the line and space pattern was observed with a scanning electron microscope ("S-4200" manufactured by Hitachi Keiki Co., Ltd.), the line width at the upper part of the film and the intermediate part The case where the difference in the line width was 10% or less and the variation in the line width was 20% or less was evaluated as “◯”, and the case where the difference was more than “X” was evaluated.

<Intermixing>
With respect to intermixing, evaluation was made with “◯” indicating that no interlayer turbidity was observed between the substrate (A) or (B) and the resin composition (I) or (II), and “×” indicating what was observed.

<Developability>
Regarding the developability, “◯” was evaluated when the area other than the pattern was uniform after exposure, development after PEB, and a rinsing process with pure water, and “X” was evaluated otherwise.

  As shown in Table 2, when the resin composition (I) is used as a resist, not only the substrate (A) but also the substrate (B) formed with the resin solution (I) is good. The applicability was shown. Further, at that time, the resist alone shows a good pattern forming ability without mixing with the lower resin film.

  The resin composition for forming a second resist contains a resin (A-1) soluble in an alcohol solvent, and since the solvent system is alcohol, the resin film formed in the lower layer is not damaged on the resin composition. Patterning is possible. As a result, the second resist layer can be formed and patterned on the resin film having the pattern without damaging the pattern. Therefore, it can be used very suitably for the manufacture of semiconductor devices that are expected to be further miniaturized in the future.

It is a schematic diagram explaining the process of forming a resist pattern. It is a schematic diagram explaining the process of forming a resist pattern.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1; Substrate, 2; First resist layer, 21; Pattern latent image part, 22; First resist pattern, 23; Deactivated first resist pattern, 3; Air or liquid for immersion exposure, 4; Mask 5; second resist layer 51; pattern latent image portion; 52; second resist pattern; 6; liquid for immersion exposure;

Claims (4)

(I) using a positive-type radiation-sensitive resin composition for the first resist layer forming a first resist layer is formed on a substrate and exposed to radiation to essential region at the said first resist layer Thereafter, by developing, a step of forming a first resist pattern;
( Ii ) After forming the second resist layer on the substrate on which the first resist pattern is formed using the positive radiation-sensitive composition for forming the second resist layer, the second resist layer and the second resist layer by exposing by irradiating the essential region at one resist pattern, forming a pattern latent image part the first resist pattern with inactivate to light, the second resist layer,
( Iii ) forming a second resist pattern in the space portion of the first resist pattern by developing, a resist pattern forming method comprising:
The positive-type radiation-sensitive resin composition for forming the second resist layer contains a resin (A) that becomes alkali-soluble by the action of an acid, and a solvent (B), and the solvent (B) The method of forming a resist pattern, wherein the first resist pattern is not dissolved.   The resist pattern forming method according to claim 1, wherein the solvent (B) is an alcohol solvent. The alcohol solvent is 1-butyl alcohol, 2-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, tert-amyl alcohol, neopentyl alcohol, 2- Methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, 2,3-dimethyl-2-butanol, 3 , 3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-diethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3 -Pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, - methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol and claim 2 wherein at least one of cyclohexanol Resist pattern forming method. The resist pattern formation method in any one of Claims 1 thru | or 3 in which the said resin (A) contains the repeating unit represented by following General formula (1).

[In General Formula (1), R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group, and R ² represents a single bond, methylene, a linear or branched alkylene group having 2 to 6 carbon atoms, or An alicyclic alkylene group having 4 to 12 carbon atoms is shown. ]

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