Polymer manufacturing method, radiation-sensitive resin composition and its manufacturing method

Abstract

To provide a radiation-sensitive resin composition that can exhibit sensitivity, LWR performance, pattern rectangularity and the like, at a sufficient level, and has improved defects; a method for producing the same; and a method for producing a polymer to be used for the same.SOLUTION: The method for producing the polymer includes subjecting a monomer having a phenolic hydroxyl group or a protected form thereof to free-radical polymerization in the coexistence of a polymerization initiator to obtain the polymer. The free-radical polymerization is continuously performed in a unidirectional flow state from an introduction part to a discharge part, in a flow pass which includes the introduction part, the discharge part, and a heating part provided between the introduction part and the discharge part.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for producing a polymer that can be suitably used particularly for a resist, as well as a radiation-sensitive resin composition containing the polymer and a method for producing the same. [Background technology]

[0002] Photolithography techniques using resist compositions are used for forming fine circuits in semiconductor elements. As a typical procedure, for example, an acid is generated by exposing a coating of the resist composition to radiation through a mask pattern, and a difference in solubility of the resin in an alkaline or organic developer is generated between an exposed portion and an unexposed portion by a reaction catalyzed by the acid, thereby forming a resist pattern on a substrate.

[0003] The photolithography technology mentioned above promotes finer patterns by using short-wavelength radiation from ArF excimer lasers, etc., and also by using liquid immersion lithography, in which exposure is performed with the space between the lens of the exposure device and the resist film filled with a liquid medium.

[0004] As efforts toward further technological advances continue, a technology has been proposed in which a quencher (diffusion control agent) is added to a resist composition to capture the acid that has diffused to the unexposed area through a salt exchange reaction, thereby improving the lithography performance of ArF exposure (Patent Document 1). In addition, lithography using shorter wavelength radiation such as electron beams, X-rays, and EUV (extreme ultraviolet) is also being considered as a next-generation technology. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5556765 Summary of the Invention [Problem to be solved by the invention]

[0006] In these efforts toward next-generation technologies, there is a demand for resist performances equal to or greater than those of conventional resists in terms of sensitivity, line width roughness (LWR) performance indicating the variation in line width of a resist pattern, rectangularity of the cross-sectional shape of the pattern (hereinafter also referred to as pattern rectangularity, etc.), etc. However, existing radiation-sensitive resin compositions do not provide such properties at a sufficient level.

[0007] An object of the present invention is to provide a radiation-sensitive resin composition which is capable of exhibiting sufficient levels of sensitivity, LWR performance, pattern rectangularity, etc. and which has improved defects, a method for producing the same, and a method for producing a polymer used therein. [Means for solving the problem]

[0008] As a result of intensive research into solving the above problem, the present inventors discovered that the above object can be achieved by adopting the following configuration, and thus completed the present invention.

[0009] That is, in one embodiment, the present invention provides A method for producing a polymer (hereinafter also referred to as "polymer A"), comprising the steps of: radically polymerizing a monomer having a phenolic hydroxyl group or a protected form thereof (hereinafter also referred to as "monomer 1") in the presence of a polymerization initiator to obtain a polymer, the method comprising the steps of: The radical polymerization relates to a method for producing a polymer, in which the radical polymerization is continuously carried out in a flow path including an inlet part, a discharge part, and a heating part provided between the inlet part and the discharge part, in a unidirectional flow state from the inlet part to the discharge part.

[0010] In the method for producing a polymer of the present invention, radical polymerization in the coexistence of a monomer having a phenolic hydroxyl group or a protected form thereof and a polymerization initiator is continuously carried out in a flow path having an inlet, an outlet, and a heating section provided between the inlet and the outlet in a state of unidirectional flow from the inlet to the outlet, so that a polymer suitable for a radiation-sensitive resin composition can be obtained. As the mechanism of action for the manifestation of the above effect, it is presumed that, although the scope of the rights of the present invention is not necessarily limited by this presumption, the use of the above production method results in a polymer in which the reactivity of the monomer is controlled, and as a result, when the obtained polymer is used as a resist resin, various resist performances such as defect reduction are suitably improved.

[0011] In one embodiment, the method for producing a polymer of the present invention includes the steps of: The flow path preferably has a region of 100° C. to 150° C. by heating the heating unit. With the above-mentioned configuration, a polymer having more suitably controlled monomer reactivity can be obtained, and when the obtained polymer is used as a resist resin, various resist properties such as reduced defects can be suitably improved.

[0012] In one embodiment, the method for producing a polymer of the present invention includes the steps of: The monomer having a phenolic hydroxyl group or a protected form thereof is preferably represented by the following formula (1). [ka] (In the above formula (1), R α is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. L is a single bond, -COO- * Or -O- * * is a bond on the aromatic ring side. R 11 R is a hydrogen atom, an acyl group having 2 to 20 carbon atoms, or an alkoxycarbonyl group having 2 to 20 carbon atoms. 11 If there are multiple R 11 are the same or different from each other. R 12R is a cyano group, a nitro group, an alkyl group, a fluorinated alkyl group, an alkoxycarbonyloxy group, an acyl group, or an acyloxy group. 12 If there are multiple R 12 are the same or different from each other. n 1 is an integer from 0 to 2, and m 1 is an integer from 1 to 8, and m 2 is an integer from 0 to 8, provided that 1≦m 1 +m 2 ≦2n 1 +5 is met.) By having the above-mentioned structure, when the obtained polymer is used as a resist resin, it is possible to preferably improve various resist performances such as reducing defects, compared to, for example, a case in which the same monomer is used in batch synthesis.

[0013] In one embodiment, the method for producing a polymer of the present invention includes the steps of: The radical polymerization is preferably carried out in the coexistence of a structural unit having an acid-dissociable group (hereinafter also referred to as "monomer 2"). By having the above-mentioned structure, when the obtained polymer is used as a resist resin, it is possible to suitably improve various resist performances such as defect reduction, compared with the case of batch synthesis using the same monomer containing a structural unit having an acid-dissociable group.

[0014] On the other hand, the present invention provides, as another embodiment, The present invention also relates to a radiation-sensitive resin composition comprising the polymer obtained by the above-mentioned method for producing a polymer and a solvent.

[0015] Since the radiation-sensitive resin composition of the present invention contains the polymer obtained by the above-mentioned production method, it is possible to suitably improve various resist properties, such as reducing defects in the photoresist process.

[0016] In addition, the present invention provides, as another embodiment, The present invention relates to a method for producing a radiation-sensitive resin composition, which includes a step of mixing a polymer obtained by the method for producing a polymer with a solvent (hereinafter also referred to as "solvent 1").

[0017] In the method for producing a radiation-sensitive resin composition of the present invention, the polymer obtained by the above-mentioned production method is contained, and therefore the obtained radiation-sensitive resin composition has favorable improvements in various resist performances, such as reduced defects, in a photoresist process. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic diagram showing a synthesis method in an example. [Diagram 2] 1 is a graph showing a change in monomer composition with reaction time in an example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, the embodiments of the present invention will be described in detail, but the present invention is not limited to these embodiments.

[0020] <Polymer A> Polymer A of the present invention is a polymer that contains a monomer having a phenolic hydroxyl group or a protected form thereof as a constituent unit, and can be obtained by radical polymerization in the coexistence of the monomer having a phenolic hydroxyl group or a protected form thereof and a polymerization initiator.

[0021] (Monomer 1) In the present invention, the monomer having a phenolic hydroxyl group or a protected form thereof (monomer 1) includes a phenolic hydroxyl group or a protected form of the phenolic hydroxyl group in the above structure. Monomer 1 is not particularly limited as long as it has a phenolic hydroxyl group or a structure in which the phenolic hydroxyl group is protected by a protecting group. A known protecting group can be appropriately used for protecting the phenolic hydroxyl group.

[0022] After the monomer 1 is polymerized with, for example, the monomer 2, the protecting group of the phenolic hydroxyl group is deprotected by, for example, the action of an alkali in the deprotection step described below, to give the phenolic hydroxyl group to the polymer.

[0023] The monomer 1 is preferably represented by the following formula (1).

[0024] [ka] (In the above formula (1), R α is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. L is a single bond, -COO- * Or -O- * * is a bond on the aromatic ring side. R 11 R is a hydrogen atom, an acyl group having 2 to 20 carbon atoms, or an alkoxycarbonyl group having 2 to 20 carbon atoms. 11 If there are multiple R 11 are the same or different from each other. R 12 R is a cyano group, a nitro group, an alkyl group, a fluorinated alkyl group, an alkoxycarbonyloxy group, an acyl group, or an acyloxy group. 12 If there are multiple R 12 are the same or different from each other. n 1 is an integer from 0 to 2, and m 1 is an integer from 1 to 8, and m 2 is an integer from 0 to 8, provided that 1≦m 1 +m 2 ≦2n 1 +5 is met.)

[0025] R α is preferably a hydrogen atom or a methyl group.

[0026] L is a single bond or -COO- * It is preferable that:

[0027] R 11 Examples of the acyl group having 2 to 20 carbon atoms represented by the formula (I) include aliphatic or aromatic acyl groups having 2 to 12 carbon atoms, such as an acetyl group, a propionyl group, a benzoyl group, and an acryloyl group. Of these, an acetyl group is preferred.

[0028] R 11Examples of the alkoxycarbonyl group having 2 to 20 carbon atoms represented by the formula (I) include linear or alicyclic alkoxycarbonyloxy groups having 2 to 16 carbon atoms, such as a methoxycarbonyl group, an ethoxycarbonyl group, an n-propoxycarbonyl group, an i-propoxycarbonyl group, an n-butoxycarbonyl group, an i-butoxycarbonyl group, a t-butoxycarbonyl group, and an adamantylmethyloxycarbonyloxy group. Of these, a t-butoxycarbonyl group is preferred.

[0029] R 12 Examples of the alkyl group represented by the formula (I) include linear or branched alkyl groups having 1 to 8 carbon atoms, such as a methyl group, an ethyl group, or a propyl group. Examples of the fluorinated alkyl group include linear or branched fluorinated alkyl groups having 1 to 8 carbon atoms, such as a trifluoromethyl group or a pentafluoroethyl group. Examples of the alkoxycarbonyloxy group include linear or alicyclic alkoxycarbonyloxy groups having 2 to 16 carbon atoms, such as a methoxycarbonyloxy group, a butoxycarbonyloxy group, or an adamantylmethyloxycarbonyloxy group. Examples of the acyl group include 11 Examples of the acyloxy group include aliphatic or aromatic acyloxy groups having 2 to 12 carbon atoms, such as an acetyloxy group, a propionyloxy group, a benzoyloxy group, and an acryloyloxy group.

[0030] The above m 1 As the number, an integer of 1 to 3 is preferable, and 1 or 2 is more preferable.

[0031] The above m 2 is preferably an integer of 0 to 3, and more preferably an integer of 0 to 2.

[0032] Examples of the monomer 1 represented by the above formula (1) include monomers represented by the following formulas (1-1) to (1-12).

[0033] [ka]

[0034] [ka]

[0035] In the above formulas (1-1) to (1-12), R α is synonymous with the above formula (1).

[0036] The content of monomer 1 (total when multiple types of monomer 1 are present) is preferably 10 mol % or more, more preferably 15 mol % or more, even more preferably 20 mol % or more, and particularly preferably 25 mol % or more, of all monomers forming polymer A. Meanwhile, the content is preferably 70 mol % or less, more preferably 65 mol % or less, even more preferably 60 mol % or less, and particularly preferably 55 mol % or less. By setting the content of monomer 1 within the above range, the radiation-sensitive resin composition containing polymer A can further improve the sensitivity and LWR performance.

[0037] (Monomer 2) It is preferable that polymer A of the present invention further contains a structural unit (monomer 2) having an acid-dissociable group.

[0038] Monomer 2 is not particularly limited as long as it has an acid-dissociable group, but from the viewpoints of resist performance, pattern formability, etc., it is preferable to use a (meth)acrylic acid ester monomer having an acid-dissociable group. The term "acid-dissociable group" refers to a group that substitutes a hydrogen atom of an alkali-soluble group such as a carboxy group, a phenolic hydroxyl group, a sulfo group, or a sulfonamide group, and dissociates under the action of an acid. Therefore, the acid-dissociable group is bonded to the oxygen atom that was bonded to the hydrogen atom in these functional groups.

[0039] The monomer 2 is preferably represented by the following formula (2).

[0040] [ka] (In the above formula (2), R 7 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R 8 is a halogen-substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms. R 9 and R 10 each independently represents a halogen-substituted or unsubstituted monovalent linear hydrocarbon group having 1 to 10 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a divalent alicyclic group having 3 to 20 carbon atoms constituted by combining these groups together with the carbon atom to which they are bonded.)

[0041] R 7 From the viewpoint of copolymerizability of the monomer 2, it is preferable that the alkyl group is a hydrogen atom or a methyl group.

[0042] R 8 Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms and represented by the formula (I) include a chain hydrocarbon group having 1 to 10 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, and a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms. Some or all of the hydrogen atoms in these groups may be substituted with halogen atoms (for example, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, etc.).

[0043] R 8 ~R 10 Examples of the chain hydrocarbon group having 1 to 10 carbon atoms represented by the formula (I) include a linear or branched saturated hydrocarbon group having 1 to 10 carbon atoms, and a linear or branched unsaturated hydrocarbon group having 1 to 10 carbon atoms. Some or all of the hydrogen atoms in these groups may be substituted with halogen atoms (for example, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, etc.).

[0044] R 8 ~R 10Examples of the alicyclic hydrocarbon group having 3 to 20 carbon atoms represented by the formula (1) include monocyclic or polycyclic saturated hydrocarbon groups, or monocyclic or polycyclic unsaturated hydrocarbon groups. As the monocyclic saturated hydrocarbon group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, or a cyclooctyl group is preferable. As the polycyclic cycloalkyl group, a bridged alicyclic hydrocarbon group such as a norbornyl group, an adamantyl group, a tricyclodecyl group, or a tetracyclododecyl group is preferable. The bridged alicyclic hydrocarbon group refers to a polycyclic alicyclic hydrocarbon group in which two carbon atoms that are not adjacent to each other among the carbon atoms constituting the alicyclic ring are bonded by a bond chain containing one or more carbon atoms.

[0045] R 8 Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms represented by the formula (I) include aryl groups such as a phenyl group, a tolyl group, a xylyl group, a naphthyl group, and an anthryl group; and aralkyl groups such as a benzyl group, a phenethyl group, and a naphthylmethyl group.

[0046] R 8 As the alkyl group, a linear or branched saturated hydrocarbon group having 1 to 10 carbon atoms and an alicyclic hydrocarbon group having 3 to 20 carbon atoms are preferable.

[0047] R 9 and R 10 The divalent alicyclic group having 3 to 20 carbon atoms, which is formed by combining chain hydrocarbon groups or alicyclic hydrocarbon groups represented by the formula (I) with each other and the carbon atoms to which they are bonded, is not particularly limited as long as it is a group in which two hydrogen atoms are removed from the same carbon atom constituting a carbon ring of a monocyclic or polycyclic alicyclic hydrocarbon having the above carbon number. It may be either a monocyclic hydrocarbon group or a polycyclic hydrocarbon group, and the polycyclic hydrocarbon group may be either a bridged alicyclic hydrocarbon group or a condensed alicyclic hydrocarbon group, and may be either a saturated hydrocarbon group or an unsaturated hydrocarbon group. Note that the condensed alicyclic hydrocarbon group refers to a polycyclic alicyclic hydrocarbon group formed in such a way that multiple alicyclic rings share a side (a bond between two adjacent carbon atoms).

[0048] Among the monocyclic alicyclic hydrocarbon groups, preferred saturated hydrocarbon groups include cyclopentanediyl, cyclohexanediyl, cycloheptanediyl, and cyclooctanediyl groups, while preferred unsaturated hydrocarbon groups include cyclopentenediyl, cyclohexenediyl, cycloheptenediyl, cyclooctenediyl, and cyclodecenediyl groups. Preferred polycyclic alicyclic hydrocarbon groups include bridged alicyclic saturated hydrocarbon groups, such as bicyclo[2.2.1]heptane-2,2-diyl (norbornane-2,2-diyl), bicyclo[2.2.2]octane-2,2-diyl, and tricyclo[3.3.1.1]heptane-2,2-diyl. 3,7 ]Decane-2,2-diyl group (adamantane-2,2-diyl group) and the like are preferred.

[0049] Among these, R 8 is an alkyl group having 1 to 4 carbon atoms, and R 9 and R 10 It is preferable that the alicyclic structure formed by combining these together with the carbon atoms to which they are bonded is a polycyclic or monocyclic cycloalkane structure.

[0050] Examples of the monomer 2 include monomers represented by the following formulas (2-1) to (2-6).

[0051] [ka]

[0052] In the above formulas (2-1) to (2-6), R 7 ~R 10 has the same meaning as in the above formula (2). i and j each independently represent an integer of 1 to 4. k and l each represent 0 or 1.

[0053] As i and j, 1 is preferable. 8 R is preferably a methyl group, an ethyl group, an isopropyl group, or a phenyl group. 9 and R 10 As the alkyl group, a methyl group or an ethyl group is preferable.

[0054] Furthermore, the monomer 2 may contain, in addition to or instead of the monomers represented by the above formulas (2-1) to (2-6), monomers represented by the following formulas (2-7) to (2-9), etc.

[0055] [ka]

[0056] In the above formulas (2-7) to (2-9), R 7 is the same as in formula (2) above. βf are each independently a hydrogen atom or a chain alkyl group having 1 to 5 carbon atoms. βf may be the same or different. 1 is an integer from 1 to 4.

[0057] Above R βf is preferably a hydrogen atom, a methyl group or an ethyl group. 1 As the number, 1 or 2 is preferable.

[0058] The content of monomer 2 (total when multiple types of monomer 2 are present) is preferably 20 mol % or more, more preferably 25 mol % or more, even more preferably 30 mol % or more, and particularly preferably 35 mol % or more, of all monomers forming polymer A. Meanwhile, the content is preferably 90 mol % or less, more preferably 85 mol % or less, even more preferably 80 mol % or less, and particularly preferably 75 mol % or less. By setting the content of monomer 2 within the above range, the pattern formability of the radiation-sensitive resin composition containing polymer A can be improved.

[0059] (Other monomers) As the other monomer, a monomer having a polar group (hereinafter also referred to as "monomer 3") may be appropriately contained. Examples of the polar group include a fluorine atom, an alcoholic hydroxyl group, a carboxy group, a cyano group, a nitro group, and a sulfonamide group. Among the monomers 3, a monomer having a fluorine atom, a monomer having an alcoholic hydroxyl group, and a monomer having a carboxy group are preferred, and a monomer having a fluorine atom and a monomer having an alcoholic hydroxyl group are more preferred.

[0060] Examples of the monomer 3 include monomers represented by the following formula:

[0061] [ka]

[0062] In the above formula, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0063] When monomer 3 is used, the content of monomer 3 (total when multiple types of monomer 3 are present) is preferably 2 mol % or more, more preferably 3 mol % or more, even more preferably 5 mol % or more, and particularly preferably 8 mol % or more, of all monomers forming polymer A. On the other hand, the content is preferably 40 mol % or less, more preferably 35 mol % or less, even more preferably 30 mol % or less, and particularly preferably 25 mol % or less. By setting the content of monomer 2 within the above range, the solubility of polymer A in the developer can be appropriately controlled.

[0064] (Other ingredients) In the present invention, for example, a chain transfer agent may be used within a range that does not impair the storage stability of the radiation-sensitive resin composition containing the polymer A. Examples of the chain transfer agent include 1-butanethiol, 2-butanethiol, 1-octanethiol, 1-decanethiol, 1-tetradecanethiol, cyclohexanethiol, 2-methyl-1-propanethiol, 2-mercaptoethanol, mercaptoacetic acid, and 1-thioglycerol.

[0065] (Properties of Polymer A) The molecular weight of the polymer A is not particularly limited, but the weight average molecular weight (Mw) in terms of polystyrene by gel permeation chromatography (GPC) is preferably 1,000 or more, more preferably 2,000 or more, even more preferably 3,000 or more, and particularly preferably 4,000 or more. On the other hand, the weight average molecular weight is preferably 50,000 or less, more preferably 30,000 or less, even more preferably 15,000 or less, and particularly preferably 12,000 or less. If the Mw of the polymer A is less than the lower limit, the heat resistance of the resist film obtained from the radiation-sensitive resin composition may decrease. If the Mw of the polymer A exceeds the upper limit, the developability of the resist film may decrease.

[0066] The ratio (Mw / Mn) of Mw of polymer A to the polystyrene-equivalent number average molecular weight (Mn) measured by GPC is usually 1 or more and 5 or less, preferably 1 or more and 3 or less, and more preferably 1 or more and 2 or less.

[0067] In this specification, the Mw and Mn of polymer A are values ​​measured by gel permeation chromatography (GPC) under the following conditions. GPC columns: 2 G2000HXL, 1 G3000HXL, 1 G4000HXL (all manufactured by Tosoh) Column temperature: 40℃ Elution solvent: tetrahydrofuran Flow rate: 1.0mL / min Sample concentration: 1.0% by mass Sample injection volume: 100 μL Detector: Differential refractometer Standard material: Monodisperse polystyrene

[0068] <Production Method of Polymer A> The method for producing polymer A of the present invention is a method for obtaining a polymer by radical polymerization in the coexistence of a monomer having a phenolic hydroxyl group or a protected form thereof and a polymerization initiator, The radical polymerization is continuously carried out in a flow path including an inlet portion, an outlet portion, and a heating portion provided between the inlet portion and the outlet portion in a unidirectional flow state from the inlet portion to the outlet portion.

[0069] The above-mentioned production method uses a reactor having a flow path, continuously supplies a monomer component, a polymerization initiator, and a solvent (hereinafter also referred to as "solvent 2") from the beginning of the flow path (e.g., an inlet), radically polymerizes the monomer component in the flow path to form a polymer, and discharges the polymer solution from the end of the flow path (e.g., an outlet).

[0070] The reactor has a flow path and is equipped with an inlet and an outlet.

[0071] The flow channel has a starting end to which a monomer component, a polymerization initiator and a solvent are supplied, and a terminal end from which the polymer solution is discharged.

[0072] In the flow channel, a polymer is produced by radically polymerizing the monomer components.

[0073] Examples of the shape of the flow path include a tube, a groove, and the like. Examples of the cross-sectional shape of the tube include a circle, an ellipse, a triangle, a rectangle, a pentagon, a hexagon, and the like. The cross-sectional dimensions of the tube (inner diameter in the case of a circle) can be appropriately determined so as to satisfy the range of the cross-sectional area so as to obtain the desired flow rate. The width and depth of the groove can be appropriately determined so as to satisfy the range of the cross-sectional area so as to obtain the desired flow rate.

[0074] The number of flow paths may be one, or two or more may be combined. In addition, a plurality of flow paths may be joined on the way, or one flow path 2 may be branched into a plurality of paths on the way.

[0075] The inlet portion is a portion for continuously supplying the monomer components, the polymerization initiator, and the solvent, and may be the start end of the flow path.

[0076] Examples of the introduction unit include a syringe pump, a plunger pump, a tube pump, and a diaphragm pump.

[0077] The introduction part may be composed of one supply introduction means or may be composed of a plurality of introduction means. From the viewpoint of suppressing the polymerization reaction in the introduction part, it is preferable that the introduction part is composed of, for example, a first introduction means for supplying a liquid containing a monomer component in a solvent or a liquid containing a monomer component without a solvent, and a second introduction means for supplying a liquid containing a polymerization initiator in a solvent.

[0078] The heating section heats a predetermined region of the flow channel (hereinafter, also referred to as "region H") to a predetermined temperature.

[0079] Examples of the heating unit include an oil bath, a ribbon heater, and a mantle heater.

[0080] It is preferable that the heating unit heats the region H to have a temperature range of 100° C. to 150° C. The region H may be, for example, 105° C. to 145° C. or 110° C. to 140° C.

[0081] The heating unit preferably has a temperature control means for maintaining the temperature of a predetermined region of the flow path at a predetermined temperature. The temperature control means may, for example, have a thermometer, a heater, and a control device for adjusting the output of the heater based on temperature information from the thermometer.

[0082] It is also preferable to provide a cooling section, which cools a predetermined region of the flow channel to a predetermined temperature.

[0083] The cooling unit may be, for example, an ice bath, a water bath, a circulating cooler, or the like.

[0084] The discharge portion is a portion where the polymer solution is discharged, and may be the end of the flow path.

[0085] The recovery section recovers the polymer solution discharged from the end of the flow channel, and may be integrated with the discharge section.

[0086] The collection section is preferably cooled by a cooling means.

[0087] In order to obtain polymer A, it is preferable that the polymerization initiator efficiently decomposes to generate radicals and polymerize the monomer components in a short time. For this purpose, it is preferable to use a polymerization initiator having a 5-minute half-life temperature of 60 to 120°C and to polymerize in a region (R) maintained at a temperature equal to or higher than the 5-minute half-life temperature for a residence time of 5 to 60 minutes.

[0088] The temperature of region H is equal to or higher than the 5-minute half-life temperature of the polymerization initiator, and is preferably equal to or higher than the 5-minute half-life temperature + 10°C. The temperature of region (R) is preferably equal to or lower than 140°C, and more preferably equal to or lower than 120°C. If the temperature of region (R) is equal to or higher than the 5-minute half-life temperature of the polymerization initiator, a polymer having a small variation in the ratio of constituent units per polymer chain and a narrow molecular weight distribution can be obtained in high yield. Furthermore, if the temperature of region (R) is equal to or lower than 140°C, thermal decomposition of the polymer is suppressed, and it is easy to obtain polymer A having a sufficiently narrow molecular weight distribution.

[0089] The residence time in region H (ie, the reaction time) is preferably 5 to 60 minutes.

[0090] If the residence time is 5 minutes or more, the polymerization initiator is efficiently decomposed to generate sufficient radicals, and a polymer A having a small variation in the ratio of structural units per polymer chain, a small mass average molecular weight, and a narrow molecular weight distribution can be obtained. If the residence time is 60 minutes or less, the polymerization time can be shortened and productivity can be improved.

[0091] The supply rates of the monomer components, polymerization initiator, and solvent in the flow channel are, for example, preferably 0.01 to 100 mL / min, and more preferably 0.1 to 10 mL / min.

[0092] (Polymerization initiator) It is preferable to use a polymerization initiator having a 5-minute half-life temperature of 60 to 120° C. If the 5-minute half-life temperature is 60° C. or higher, the polymerization initiator efficiently decomposes to generate radicals, which accelerates the reaction rate and produces a polymer A having a smaller variation in the ratio of constituent units per polymer chain and a narrower molecular weight distribution. If the 5-minute half-life temperature is 120° C. or lower, the temperature in region (R) is kept low and decomposition of the polymer does not occur.

[0093] The 5-minute half-life temperature is the temperature at which the decomposition rate of the polymerization initiator becomes 50% in 5 minutes. The 5-minute half-life temperature can be calculated from the reaction rate constant and the Arrhenius equation based on the 10-hour half-life temperature and activation energy of the polymerization initiator.

[0094] Examples of polymerization initiators having a 5-minute half-life temperature of 60 to 120°C include dimethyl 2,2'-azobis(2-methylpropionate) (5-minute half-life temperature: 107°C), 2,2'-azobis(2,4-dimethylvaleronitrile) (5-minute half-life temperature: 90°C), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) (5-minute half-life temperature: 66°C), 2,2'-azobisisobutyronitrile (5-minute half-life temperature: 104°C), and the like.

[0095] The amount of the polymerization initiator is preferably from 0.1 to 30 mol %, more preferably from 1 to 25 mol %, based on 100 mol % of the monomer component.

[0096] (Solvent 2) Examples of solvent 2 include chain ethers (diethyl ether, propylene glycol monomethyl ether, etc.), cyclic ethers (THF, 1,4-dioxane, etc.), esters (methyl acetate, ethyl acetate, butyl acetate, ethyl lactate, butyl lactate, propylene glycol monomethyl ether acetate, γ-butyrolactone, etc.), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), amides (N,N-dimethylacetamide, N,N-dimethylformamide, etc.), sulfoxides (dimethyl sulfoxide, etc.), aromatic hydrocarbons (benzene, toluene, xylene, etc.), aliphatic hydrocarbons (hexane, etc.), alicyclic hydrocarbons (cyclohexane, etc.), and the like.

[0097] (Post-processing) For example, it is preferable to dilute the obtained polymer solution to an appropriate solution viscosity with a good solvent as necessary, and then drop it into a large amount of a poor solvent (methanol, water, hexane, heptane, etc.) to precipitate polymer A. The above process (generally called reprecipitation) is very effective for removing unreacted monomers, polymerization initiators, etc. remaining in the polymer solution. If the unreacted materials remain as they are, they may adversely affect the performance of the resist film, so it is preferable to remove them as much as possible. The reprecipitation process may not be necessary in some cases.

[0098] Thereafter, the precipitate is filtered off and thoroughly dried to obtain Polymer A. Alternatively, after filtering, the precipitate may be used as a wet powder without being dried.

[0099] The polymer solution may be used as the radiation-sensitive resin composition as it is, or may be used as the radiation-sensitive resin composition after diluting the polymer solution with an appropriate solvent, or may be used as the radiation-sensitive resin composition after concentrating the polymer solution. In this case, additives such as storage stabilizers may be appropriately added.

[0100] <Radiation sensitive resin composition> The radiation-sensitive resin composition of the present invention contains the above-mentioned Polymer A and a solvent. The radiation-sensitive resin composition may contain other optional components as long as the effects of the present invention are not impaired.

[0101] (Polymer A) As the polymer A, the polymer A obtained by the above-mentioned method for producing the polymer A can be suitably used.

[0102] The content of polymer A is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 85% by mass or more, based on the total solid content of the radiation-sensitive resin composition.

[0103] (Other polymers) The radiation-sensitive resin composition of the present invention may contain, as the other polymer, a polymer (hereinafter also referred to as a "high fluorine content polymer") having a higher mass content of fluorine atoms than the polymer A. When the radiation-sensitive resin composition contains a high fluorine content polymer, the high fluorine content polymer can be unevenly distributed in the surface layer of the resist film relative to the polymer A, and as a result, the state of the resist film surface and the component distribution in the resist film can be controlled to a desired state.

[0104] The high fluorine content polymer preferably has, for example, a structural unit derived from monomer 2 in polymer A as necessary and also has a structural unit represented by the following formula (3) (hereinafter also referred to as "structural unit G"). [ka]

[0105] In the above formula (3), R 13 is a hydrogen atom, a methyl group, or a trifluoromethyl group. L is a single bond, oxygen atom, sulfur atom, -COO-, -SO 2 ONH-, -CONH- or -OCONH-. 14 represents a monovalent fluorinated chain hydrocarbon group having 1 to 20 carbon atoms or a monovalent fluorinated alicyclic hydrocarbon group having 3 to 20 carbon atoms.

[0106] Above R 13From the viewpoint of copolymerizability of the monomer that gives the structural unit G, a hydrogen atom or a methyl group is preferable, and a methyl group is more preferable.

[0107] Above G L From the viewpoint of copolymerizability of the monomer that gives the structural unit G, a single bond and -COO- are preferable, and -COO- is more preferable.

[0108] Above R 14 Examples of the monovalent fluorinated chain hydrocarbon group having 1 to 20 carbon atoms represented by the formula (1) include linear or branched alkyl groups having 1 to 20 carbon atoms in which some or all of the hydrogen atoms have been substituted with fluorine atoms.

[0109] Above R 14 Examples of the monovalent fluorinated alicyclic hydrocarbon group having 3 to 20 carbon atoms represented by the following formula include monocyclic or polycyclic hydrocarbon groups having 3 to 20 carbon atoms in which some or all of the hydrogen atoms have been substituted with fluorine atoms.

[0110] Above R 14 As the alkyl group, a fluorinated chain hydrocarbon group is preferable, a fluorinated alkyl group is more preferable, and a 2,2,2-trifluoroethyl group, a 1,1,1,3,3,3-hexafluoropropyl group and a 5,5,5-trifluoro-1,1-diethylpentyl group are further preferable.

[0111] When the high fluorine content polymer has the structural unit G, the content of the structural unit G is preferably 10 mol% or more, more preferably 15 mol% or more, even more preferably 20 mol% or more, and particularly preferably 25 mol% or more, based on the total structural units constituting the high fluorine content polymer. The content is preferably 60 mol% or less, more preferably 50 mol% or less, and even more preferably 40 mol% or less. By setting the content of the structural unit G within the above range, the mass content of fluorine atoms in the high fluorine content polymer can be more appropriately adjusted, and the uneven distribution of fluorine atoms in the surface layer of the resist film can be further promoted.

[0112] The high fluorine content polymer may have a fluorine atom-containing structural unit represented by the following formula (f-1) (hereinafter also referred to as structural unit H) in addition to the structural unit G. By having the structural unit H, the high fluorine content polymer has improved solubility in an alkaline developer, and the occurrence of development defects can be suppressed. [ka]

[0113] The structural unit H is roughly classified into two types: (x) a case having an alkali-soluble group, and (y) a case having a group that dissociates under the action of an alkali to increase the solubility in an alkali developer (hereinafter, also referred to simply as an "alkali dissociable group"). In both (x) and (y), R C R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. D is a single bond, a (s+1)-valent hydrocarbon group having 1 to 20 carbon atoms, and R of this hydrocarbon group E At the end of the side, there is an oxygen atom, a sulfur atom, and -NR dd R is a structure in which -, a carbonyl group, -COO- or -CONH- is bonded, or a structure in which some of the hydrogen atoms in the hydrocarbon group are replaced by an organic group having a hetero atom. dd represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. s represents an integer of 1 to 3.

[0114] When the structural unit H has (x) an alkali-soluble group, R F is a hydrogen atom, and A 1 is an oxygen atom, -COO-* or -SO 2 O-*. * is R F The binding site of W is shown. 1 A is a single bond, a hydrocarbon group having 1 to 20 carbon atoms, or a divalent fluorinated hydrocarbon group. 1 If is an oxygen atom, W 1 A 1 is a fluorinated hydrocarbon group having a fluorine atom or a fluoroalkyl group on the carbon atom to which R is bonded. E is a single bond or a divalent organic group having 1 to 20 carbon atoms. When s is 2 or 3, multiple RE , W 1 , A 1 and R F may be the same or different. When the structural unit H has (x) an alkali-soluble group, it is possible to increase the affinity for an alkali developer and suppress development defects. As the structural unit H having (x) an alkali-soluble group, A 1 is an oxygen atom and W 1 It is particularly preferred that R is a 1,1,1,3,3,3-hexafluoro-2,2-methanediyl group.

[0115] When the structural unit H has (y) an alkali dissociable group, R F is a monovalent organic group having 1 to 30 carbon atoms, 1 is an oxygen atom, -NR aa -, -COO-* or -SO 2 O-*. R aa is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. * is R F The binding site of W is shown. 1 R is a single bond or a divalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. E A is a single bond or a divalent organic group having 1 to 20 carbon atoms. 1 -COO-* or -SO 2 If O-*, then W 1 or R F A 1 A has a fluorine atom on the carbon atom bonded to or adjacent to the carbon atom. 1 is an oxygen atom, W 1 , R E is a single bond, and R D R is a hydrocarbon group having 1 to 20 carbon atoms. E A carbonyl group is bonded to the end of the R F is an organic group having a fluorine atom. When s is 2 or 3, multiple R E , W 1 , A 1 and R Fmay be the same or different. When the structural unit H has (y) an alkali dissociable group, the surface of the resist film changes from hydrophobic to hydrophilic in the alkaline development step. As a result, the affinity to the developer is significantly increased, and development defects can be more efficiently suppressed. As the structural unit H having (y) an alkali dissociable group, A 1 is -COO-* and R F Or W 1 Or, it is particularly preferable that both of them have a fluorine atom.

[0116] R C From the viewpoint of copolymerizability of the monomer that gives the structural unit H, etc., a hydrogen atom or a methyl group is preferable, and a methyl group is more preferable.

[0117] R E When is a divalent organic group, it is preferably a group having a lactone structure, more preferably a group having a polycyclic lactone structure, and more preferably a group having a norbornane lactone structure.

[0118] When the high fluorine content polymer has the structural unit H, the content of the structural unit H is preferably 10 mol% or more, more preferably 20 mol% or more, even more preferably 30 mol% or more, and particularly preferably 35 mol% or more, based on the total structural units constituting the high fluorine content polymer. The content is preferably 90 mol% or less, more preferably 75 mol% or less, and even more preferably 60 mol% or less. By setting the content of the structural unit H in the above range, the water repellency of the resist film during immersion exposure can be further improved.

[0119] The Mw of the high fluorine content polymer is preferably 1,000 or more, more preferably 2,000 or more, even more preferably 3,000 or more, and particularly preferably 5,000 or more. The Mw is preferably 50,000 or less, more preferably 30,000 or less, even more preferably 20,000 or less, and particularly preferably 15,000 or less.

[0120] The Mw / Mn of the high fluorine content polymer is usually at least 1, and more preferably at least 1.1. The Mw / Mn is usually at most 5, and is preferably at most 3, more preferably at most 2, and even more preferably at most 1.7.

[0121] The content of the high fluorine content polymer is preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, even more preferably 0.5 parts by mass or more, and particularly preferably 1 part by mass or more, relative to 100 parts by mass of the polymer A. The content is preferably 15 parts by mass or less, more preferably 10 parts by mass or less, even more preferably 8 parts by mass or less, and particularly preferably 5 parts by mass or less.

[0122] By setting the content of the high fluorine content polymer within the above range, the high fluorine content polymer can be more effectively localized in the surface layer of the resist film, and as a result, the water repellency of the surface of the resist film during immersion exposure can be further improved. The radiation-sensitive resin composition may contain one or more types of high fluorine content polymers.

[0123] (Method of synthesizing high fluorine content polymers) The high fluorine content polymer can be synthesized by the same method as the synthesis method of polymer A described above.

[0124] (Radiation-sensitive acid generator) The radiation-sensitive resin composition of the present invention preferably contains a radiation-sensitive acid generator. The radiation-sensitive acid generator is a component that generates an acid upon exposure to light. The radiation-sensitive acid generator is preferably represented by the following formula (p-1). [ka] (In the above formula (p-1), R p1 is a monovalent group containing a ring structure having six or more ring members. R p2 is a divalent linking group. R p3 and R p4are each independently a hydrogen atom, a fluorine atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms, or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. R p5 and R p6 are each independently a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. n p1 is an integer from 0 to 10. p2 is an integer from 0 to 10. p3 is an integer from 0 to 10. p1 +n p2 +n p3 is an integer between 1 and 30. n p1 If is 2 or more, multiple R p2 are the same or different from each other. n p2 If is 2 or more, multiple R p3 are the same or different, and multiple R p4 are the same or different from each other. n p3 If is 2 or more, multiple R p5 are the same or different, and multiple R p6 are the same or different. Z + is a monovalent onium cation.

[0125] R p1 Examples of the monovalent group containing a ring structure represented by the formula (I) include a monovalent group containing an alicyclic structure having 5 or more ring members, a monovalent group containing an aliphatic heterocyclic structure having 5 or more ring members, a monovalent group containing an aromatic ring structure having 6 or more ring members, and a monovalent group containing an aromatic heterocyclic structure having 6 or more ring members.

[0126] Examples of the alicyclic structure having 5 or more ring members include a monocyclic cycloalkane structure such as a cyclopentane structure, a cyclohexane structure, a cycloheptane structure, a cyclooctane structure, a cyclononane structure, a cyclodecane structure, or a cyclododecane structure; A monocyclic cycloalkene structure such as a cyclopentene structure, a cyclohexene structure, a cycloheptene structure, a cyclooctene structure, or a cyclodecene structure; Polycyclic cycloalkane structures such as norbornane structures, adamantane structures, tricyclodecane structures, and tetracyclododecane structures; Examples include a norbornene structure and a polycyclic cycloalkene structure such as a tricyclodecene structure.

[0127] Examples of the aliphatic heterocyclic structure having 5 or more ring members include Lactone structures such as a pentanolactone structure, a hexanolactone structure, a norbornanelactone structure, etc.; Sultone structures such as a pentano sultone structure, a hexano sultone structure, and a norbornane sultone structure; Oxygen atom-containing heterocyclic structures such as an oxacyclopentane structure, an oxacycloheptane structure, an oxanorbornane structure, etc.; Nitrogen atom-containing heterocyclic structures such as an azacyclopentane structure, an azacyclohexane structure, and a diazabicyclooctane structure; Examples of the heterocyclic structure include a sulfur atom-containing heterocyclic structure such as a thiacyclopentane structure, a thiacyclohexane structure, and a thianorbornane structure.

[0128] Examples of the aromatic ring structure having 6 or more ring members include a benzene structure, a naphthalene structure, a phenanthrene structure, and an anthracene structure.

[0129] Examples of the aromatic heterocyclic structure having 6 or more ring members include oxygen atom-containing heterocyclic structures such as a furan structure, a pyran structure, and a benzopyran structure, and nitrogen atom-containing heterocyclic structures such as a pyridine structure, a pyrimidine structure, and an indole structure.

[0130] R p1The lower limit of the number of ring members of the ring structure may be 6, preferably 7, more preferably 8, even more preferably 9, and particularly preferably 10. On the other hand, the upper limit of the number of ring members is preferably 15, more preferably 14, even more preferably 13, and particularly preferably 12. By setting the number of ring members within the above range, the diffusion length of the acid can be further suitably shortened, and as a result, various performances of the chemically amplified resist material can be further improved.

[0131] R p1 A part or all of the hydrogen atoms in the ring structure may be substituted with a substituent. Examples of the substituent include halogen atoms such as fluorine atom, chlorine atom, bromine atom, and iodine atom, hydroxy group, carboxy group, cyano group, nitro group, alkoxy group, alkoxycarbonyl group, alkoxycarbonyloxy group, acyl group, and acyloxy group. Among these, a hydroxy group is preferred.

[0132] R p1 As the aryl group, a monovalent group containing an alicyclic structure having 5 or more ring members and a monovalent group containing an aliphatic heterocyclic structure having 5 or more ring members are preferable, a monovalent group containing an alicyclic structure having 6 or more ring members and a monovalent group containing an aliphatic heterocyclic structure having 6 or more ring members are more preferable, a monovalent group containing an alicyclic structure having 9 or more ring members and a monovalent group containing an aliphatic heterocyclic structure having 9 or more ring members are even more preferable, an adamantyl group, a hydroxyadamantyl group, a norbornane lactone-yl group, a norbornane sultone-yl group and a 5-oxo-4-oxatricyclo[4.3.1.13,8]undecane-yl group are even more preferable, and an adamantyl group is particularly preferable.

[0133] R p2 Examples of the divalent linking group represented by the formula (I) include a carbonyl group, an ether group, a carbonyloxy group, a sulfide group, a thiocarbonyl group, a sulfonyl group, and a divalent hydrocarbon group. p2The divalent linking group represented by the formula (I) is preferably a carbonyloxy group, a sulfonyl group, an alkanediyl group, or a cycloalkanediyl group, more preferably a carbonyloxy group or a cycloalkanediyl group, further preferably a carbonyloxy group or a norbornanediyl group, and particularly preferably a carbonyloxy group.

[0134] R p3 and R p4 Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by the formula (I) include an alkyl group having 1 to 20 carbon atoms. p3 and R p4 Examples of the monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by the formula (1) include a fluorinated alkyl group having 1 to 20 carbon atoms. p3 and R p4 As the alkyl group, a hydrogen atom, a fluorine atom and a fluorinated alkyl group are preferable, a fluorine atom and a perfluoroalkyl group are more preferable, and a fluorine atom and a trifluoromethyl group are further preferable.

[0135] R p5 and R p6 Examples of the monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by the formula (1) include a fluorinated alkyl group having 1 to 20 carbon atoms. p5 and R p6 As the alkyl group, a fluorine atom and a fluorinated alkyl group are preferable, a fluorine atom and a perfluoroalkyl group are more preferable, a fluorine atom and a trifluoromethyl group are further preferable, and a fluorine atom is particularly preferable.

[0136] n p1 As the aryl group, an integer of 0 to 5 is preferable, an integer of 0 to 3 is more preferable, an integer of 0 to 2 is further preferable, and 0 and 1 are particularly preferable.

[0137] n p2 As the number, an integer of 0 to 2 is more preferable, 0 and 1 are further preferable, and 0 is particularly preferable.

[0138] n p3is preferably an integer of 0 to 5, more preferably an integer of 1 to 4, further preferably an integer of 1 to 3, and particularly preferably 1 or 2. p3 By making n equal to or greater than 1, the strength of the acid generated from the compound of formula (p-1) can be increased, and as a result, the LWR performance and the like of the radiation-sensitive resin composition can be further improved. p3 The upper limit of is preferably 4, more preferably 3, and even more preferably 2.

[0139] In the above formula (p-1), n p1 +n p2 +n p3 is an integer between 1 and 30. p1 +n p2 +n p3 The lower limit of n is preferably 2, and more preferably 4. p1 +n p2 +n p3 The upper limit of is preferably 20, more preferably 10.

[0140] Above Z + Examples of the monovalent onium cation represented by the formula (X-1) include radioactive onium cations containing elements such as S, I, O, N, P, Cl, Br, F, As, Se, Sn, Sb, Te, and Bi, and examples thereof include sulfonium cations, tetrahydrothiophenium cations, iodonium cations, phosphonium cations, diazonium cations, and pyridinium cations. Among these, sulfonium cations and iodonium cations are preferred. The sulfonium cations and iodonium cations are preferably represented by the following formulas (X-1) to (X-6).

[0141] [ka]

[0142] [ka]

[0143] [ka]

[0144] [ka]

[0145] [ka]

[0146] [ka]

[0147] In the above formula (X-1), R a1 , R a2 and R a3 each independently represents a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, an alkoxy group or an alkoxycarbonyloxy group, a substituted or unsubstituted monocyclic or polycyclic cycloalkyl group having 3 to 12 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms, a hydroxy group, a halogen atom, -OSO 2 -R P , -SO 2 -R Q Or -SR T or a ring structure formed by combining two or more of these groups together. The ring structure may contain a heteroatom such as O or S between the carbon-carbon bonds that form the skeleton. R P , R Q and R T are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted alicyclic hydrocarbon group having 5 to 25 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms. k1, k2, and k3 are each independently an integer of 0 to 5. R a1 ~R a3 And R P , R Q and R TIf there are multiple R a1 ~R a3 And R P , R Q and R T may be the same or different.

[0148] In the above formula (X-2), R b1 is a substituted or unsubstituted linear or branched alkyl or alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted acyl group having 2 to 8 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 8 carbon atoms, or a hydroxy group. k is 0 or 1. k When is 0, k4 is an integer from 0 to 4, and n k When is 1, k4 is an integer from 0 to 7. b1 If there are multiple, multiple R b1 may be the same or different, and multiple R b1 R may represent a ring structure formed by combining with each other. b2 L is a substituted or unsubstituted linear or branched alkyl group having 1 to 7 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 or 7 carbon atoms. C is a single bond or a divalent linking group. k5 is an integer of 0 to 4. R b2 If there are multiple, multiple R b2 may be the same or different, and multiple R b2 may represent a ring structure formed by combining with each other. q is an integer of 0 to 3. In the formula, S + The ring structure containing the following may contain a heteroatom such as O or S between the carbon-carbon bonds that form the backbone.

[0149] In the above formula (X-3), R c1 , R c2 and R c3 are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms.

[0150] In the above formula (X-4), Rg1 is a substituted or unsubstituted linear or branched alkyl or alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted acyl group having 2 to 8 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 8 carbon atoms, or a hydroxy group. k is 0 or 1. k2 When is 0, k10 is an integer from 0 to 4, and n k2 When is 1, k10 is an integer from 0 to 7. R g1 If there are multiple, multiple R g1 may be the same or different, and multiple R g1 R may represent a ring structure formed by combining with each other. g2 and R g3 are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, an alkoxy group or an alkoxycarbonyloxy group, a substituted or unsubstituted monocyclic or polycyclic cycloalkyl group having 3 to 12 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms, a hydroxy group, a halogen atom, or a ring structure formed by combining these groups together. k11 and k12 are each independently an integer of 0 to 4. R g2 and R g3 If there are multiple R g2 and R g3 may be the same or different.

[0151] In the above formula (X-5), R d1 and R d2 are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, an alkoxy group or an alkoxycarbonyl group, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms, a halogen atom, a halogenated alkyl group having 1 to 4 carbon atoms, a nitro group, or a ring structure formed by combining two or more of these groups together. k6 and k7 are each independently an integer of 0 to 5. R d1 and R d2 If there are multiple R d1 and R d2may be the same or different.

[0152] In the above formula (X-6), R e1 and R e2 are each independently a halogen atom, a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms. k8 and k9 are each independently an integer of 0 to 4.

[0153] Examples of the radiation-sensitive acid generator represented by formula (p-1) above include radiation-sensitive acid generators represented by the following formulas (p-1-1) to (p-1-35) (hereinafter also referred to as "radiation-sensitive acid generator (p-1-1) to radiation-sensitive acid generator (p-1-35)").

[0154] [ka]

[0155] [ka]

[0156] [ka]

[0157] In the above formulas (p-1-1) to (p-1-35), Z + is a monovalent onium cation.

[0158] Among these, the radiation-sensitive acid generators represented by the above formulas (p-1-1), (p-1-9), (p-1-11), (p-1-13), (p-1-17), (p-1-23), (p-1-25) and (p-1-35) are preferred.

[0159] These radiation-sensitive acid generators may be used alone or in combination of two or more. The lower limit of the content of the radiation-sensitive acid generator is preferably 0.1 parts by mass, more preferably 1 part by mass, and even more preferably 5 parts by mass, relative to 100 parts by mass of the resin. The upper limit of the content is preferably 50 parts by mass, more preferably 40 parts by mass, and even more preferably 30 parts by mass. This allows the resist pattern to exhibit excellent sensitivity and LWR performance during formation.

[0160] (Acid diffusion control agent) The radiation-sensitive resin composition of the present invention may contain an acid diffusion controller as necessary. The acid diffusion controller controls the diffusion phenomenon in the resist film of the acid generated from the radiation-sensitive acid generator upon exposure, and has the effect of suppressing undesirable chemical reactions in the non-exposed region. In addition, the storage stability of the obtained radiation-sensitive resin composition is improved. Furthermore, the resolution of the resist pattern is further improved, and the change in the line width of the resist pattern due to the fluctuation of the delay time from exposure to development treatment can be suppressed, and a radiation-sensitive resin composition with excellent process stability can be obtained.

[0161] Examples of the acid diffusion controller include a compound represented by the following formula (4) (hereinafter also referred to as "nitrogen-containing compound (I)"), a compound having two nitrogen atoms in the same molecule (hereinafter also referred to as "nitrogen-containing compound (II)"), a compound having three nitrogen atoms (hereinafter also referred to as "nitrogen-containing compound (III)"), an amide group-containing compound, a urea compound, and a nitrogen-containing heterocyclic compound.

[0162] [ka]

[0163] In the above formula (4), R 22 , R 23 and R 24 are each independently a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group.

[0164] Examples of the nitrogen-containing compound (I) include monoalkylamines such as n-hexylamine; dialkylamines such as di-n-butylamine; trialkylamines such as triethylamine; and aromatic amines such as aniline.

[0165] Examples of the nitrogen-containing compound (II) include ethylenediamine, N,N,N',N'-tetramethylethylenediamine, and the like.

[0166] Examples of the nitrogen-containing compound (III) include polyamine compounds such as polyethyleneimine and polyallylamine; polymers such as dimethylaminoethylacrylamide; and the like.

[0167] Examples of the amide group-containing compound include formamide, N-methylformamide, N,N-dimethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, propionamide, benzamide, pyrrolidone, and N-methylpyrrolidone.

[0168] Examples of the urea compound include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, and tributylthiourea.

[0169] Examples of the nitrogen-containing heterocyclic compound include pyridines such as pyridine and 2-methylpyridine; morpholines such as N-propylmorpholine and N-(undecylcarbonyloxyethyl)morpholine; pyrazines, pyrazoles, and the like.

[0170] In addition, as the nitrogen-containing organic compound, a compound having an acid dissociable group can also be used.As the nitrogen-containing organic compound having such an acid dissociable group, for example, Nt-butoxycarbonylpiperidine, Nt-butoxycarbonylimidazole, Nt-butoxycarbonylbenzimidazole, Nt-butoxycarbonyl-2-phenylbenzimidazole, N-(t-butoxycarbonyl)di-n-octylamine, N-(t-butoxycarbonyl)diethanolamine, N-(t-butoxycarbonyl)dicyclohexylamine, N-(t-butoxycarbonyl)diphenylamine, Nt-butoxycarbonyl-4-hydroxypiperidine, Nt-amyloxycarbonyl-4-hydroxypiperidine, etc. can be mentioned.

[0171] Also, as the acid diffusion control agent, an onium salt compound that generates an acid having a higher pKa than the acid generated from the radiation-sensitive acid generator upon irradiation with radiation (hereinafter, for convenience, also referred to as a "radiation-sensitive weak acid generator") can be suitably used. The acid generated from the radiation-sensitive weak acid generator is a weak acid that does not induce dissociation of the acid-dissociable group in the resin under conditions that dissociate the acid-dissociable group. In this specification, "dissociation" of the acid-dissociable group refers to dissociation upon post-exposure baking at 110°C for 60 seconds.

[0172] Examples of the radiation-sensitive weak acid generator include a sulfonium salt compound represented by the following formula (4-1) and an iodonium salt compound represented by the following formula (4-2).

[0173] [ka]

[0174] In the above formula (4-1) and formula (4-2), J + is a sulfonium cation, and U + is the iodonium cation. + Examples of the sulfonium cation represented by the formula (X-1) to (X-4) include the sulfonium cations represented by the formula (X-1) to (X-4) above. +Examples of the iodonium cation represented by the formula (X-5) to (X-6) include the iodonium cation represented by the formula (X-6). - and Q - are each independently OH - , R α -COO - , R α -SO 3 - It is an anion represented by R α R is an alkyl group, an aryl group, or an aralkyl group. α or a hydrogen atom of an aromatic ring of an aryl group or an aralkyl group may be substituted with a halogen atom, a hydroxy group, a nitro group, a halogen atom-substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.

[0175] Examples of the radiation-sensitive weak acid generator include compounds represented by the following formula:

[0176] [ka]

[0177] [ka]

[0178] The content of the acid diffusion controller is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 15 mol% or more, based on the total moles of the radiation-sensitive acid generator. The content is preferably 200 mol% or less, more preferably 100 mol% or less, and even more preferably 50 mol% or less. By setting the content of the acid diffusion controller within the above range, the lithography performance of the radiation-sensitive resin composition can be further improved. The radiation-sensitive resin composition may contain one or more types of acid diffusion controller.

[0179] (Solvent 1) Solvent 1 is not particularly limited as long as it is a solvent capable of dissolving or dispersing at least Polymer A, and, if present, the radiation-sensitive acid generator, and additives and the like that are contained as desired.

[0180] Examples of the solvent 1 include alcohol-based solvents, ether-based solvents, ketone-based solvents, amide-based solvents, ester-based solvents, and hydrocarbon-based solvents.

[0181] Examples of alcohol-based solvents include: Monoalcohol solvents having 1 to 18 carbon atoms, such as iso-propanol, 4-methyl-2-pentanol, 3-methoxybutanol, n-hexanol, 2-ethylhexanol, furfuryl alcohol, cyclohexanol, 3,3,5-trimethylcyclohexanol, and diacetone alcohol; Polyhydric alcohol solvents having 2 to 18 carbon atoms, such as ethylene glycol, 1,2-propylene glycol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, and tripropylene glycol; Examples of the polyhydric alcohol solvent include partially etherified polyhydric alcohol solvents in which some of the hydroxy groups of the above polyhydric alcohol solvents have been etherified.

[0182] Examples of ether solvents include: Dialkyl ether solvents such as diethyl ether, dipropyl ether, and dibutyl ether; Cyclic ether solvents such as tetrahydrofuran and tetrahydropyran; Aromatic ring-containing ether solvents such as diphenyl ether and anisole (methyl phenyl ether); Examples of the polyhydric alcohol solvent include polyhydric alcohol ether solvents obtained by etherifying the hydroxyl groups of the above-mentioned polyhydric alcohol solvents.

[0183] Examples of the ketone solvent include chain ketone solvents such as acetone, butanone, and methyl-iso-butyl ketone. Cyclic ketone solvents such as cyclopentanone, cyclohexanone, methylcyclohexanone, etc.: Examples include 2,4-pentanedione, acetonylacetone, and acetophenone.

[0184] Examples of the amide solvents include cyclic amide solvents such as N,N'-dimethylimidazolidinone and N-methylpyrrolidone; Examples of the solvent include chain amide solvents such as N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, and N-methylpropionamide.

[0185] Examples of ester solvents include: Monocarboxylic acid ester solvents such as n-butyl acetate and ethyl lactate; polyhydric alcohol partial ether acetate solvents such as diethylene glycol mono-n-butyl ether acetate, propylene glycol monomethyl ether acetate, and dipropylene glycol monomethyl ether acetate; Lactone solvents such as γ-butyrolactone and valerolactone; Carbonate solvents such as diethyl carbonate, ethylene carbonate, and propylene carbonate; Examples of suitable solvents include polyvalent carboxylate diesters such as propylene glycol diacetate, methoxytriglycol acetate, diethyl oxalate, ethyl acetoacetate, ethyl lactate, and diethyl phthalate.

[0186] Examples of the hydrocarbon solvent include: Aliphatic hydrocarbon solvents such as n-hexane, cyclohexane, and methylcyclohexane; Examples of the solvent include aromatic hydrocarbon solvents such as benzene, toluene, di-iso-propylbenzene, and n-amylnaphthalene.

[0187] Among these, ester-based solvents and ketone-based solvents are preferred, polyhydric alcohol partial ether acetate-based solvents, cyclic ketone-based solvents and lactone-based solvents are more preferred, and propylene glycol monomethyl ether acetate, cyclohexanone and γ-butyrolactone are even more preferred. The radiation-sensitive resin composition may contain one or more types of solvent 1.

[0188] (Other optional ingredients) The radiation-sensitive resin composition may contain other optional components in addition to the above components. Examples of the other optional components include a crosslinking agent, a localization promoter, a surfactant, an alicyclic skeleton-containing compound, and a sensitizer. These other optional components may be used alone or in combination of two or more.

[0189] <Method for producing radiation-sensitive resin composition> The method for producing the radiation-sensitive resin composition of the present invention includes a step of mixing the polymer A obtained by the method for producing the polymer A with the solvent 1.

[0190] In the above process, the radiation-sensitive resin composition can be produced by mixing polymer A and solvent 1, and, for example, a radiation-sensitive acid generator, a high fluorine content polymer, etc., as necessary, in a predetermined ratio. After mixing, the radiation-sensitive resin composition is preferably filtered, for example, through a filter having a pore size of about 0.05 μm. The solid content concentration of the radiation-sensitive resin composition is usually 0.1% by mass to 50% by mass, preferably 0.5% by mass to 30% by mass, and more preferably 1% by mass to 20% by mass.

[0191] <Method of forming resist pattern> The resist pattern forming method includes the steps of: A step of forming a resist film from the radiation-sensitive resin composition (hereinafter also referred to as a "resist film forming step"); A step of exposing the resist film to light (hereinafter also referred to as an "exposure step"); and The method includes a step of developing the exposed resist film (hereinafter, also referred to as a "developing step").

[0192] According to the above-mentioned method for forming a resist pattern, a high-quality resist pattern can be formed because the above-mentioned radiation-sensitive resin composition, which has excellent defect suppression properties, etc., is used. Each step will now be described.

[0193] [Resist film formation process] In this step, a resist film is formed from the radiation-sensitive resin composition. Examples of the substrate on which the resist film is formed include conventionally known substrates such as silicon wafers, silicon dioxide, and aluminum-coated wafers. In addition, an organic or inorganic anti-reflective film disclosed in, for example, JP-B-6-12452 and JP-A-59-93448 may be formed on the substrate. Examples of the coating method include spin coating, casting coating, and roll coating. After coating, pre-baking (PB) may be performed as necessary to volatilize the solvent in the coating film. The PB temperature is usually 60° C. to 140° C., and preferably 80° C. to 120° C. The PB time is usually 5 seconds to 600 seconds, and preferably 10 seconds to 300 seconds. The thickness of the resist film formed is preferably 10 nm to 1,000 nm, and more preferably 10 nm to 500 nm.

[0194] When performing immersion exposure, regardless of the presence or absence of a water-repellent polymer additive such as the high fluorine content polymer in the radiation-sensitive resin composition, a protective film for immersion that is insoluble in the immersion liquid may be provided on the formed resist film in order to prevent direct contact between the immersion liquid and the resist film. As the protective film for immersion, either a solvent-peelable protective film that is peeled off by a solvent before the development step (see, for example, JP-A-2006-227632) or a developer-peelable protective film that is peeled off simultaneously with development in the development step (see, for example, WO2005-069076 and WO2006-035790) may be used. However, from the viewpoint of throughput, it is preferable to use a developer-peelable protective film for immersion.

[0195] [Exposure process] In this step, the resist film formed in the resist film forming step is exposed to radiation through a photomask (or, in some cases, through an immersion medium such as water). Examples of radiation used for exposure include electromagnetic waves such as visible light, ultraviolet light, far ultraviolet light, EUV (extreme ultraviolet light), X-rays, and gamma rays; charged particle beams such as electron beams and alpha rays, depending on the line width of the desired pattern. Among these, far ultraviolet light, electron beams, and EUV are preferred, ArF excimer laser light (wavelength 193 nm), KrF excimer laser light (wavelength 248 nm), electron beams, and EUV are more preferred, and electron beams and EUV with wavelengths of 50 nm or less, which are positioned as next-generation exposure technologies, are even more preferred.

[0196] When the exposure is performed by immersion exposure, the immersion liquid used may be, for example, water or a fluorine-based inert liquid. The immersion liquid is preferably a liquid that is transparent to the exposure wavelength and has a temperature coefficient of refractive index as small as possible so as to minimize distortion of the optical image projected onto the film, but when the exposure light source is an ArF excimer laser light (wavelength 193 nm), in addition to the above-mentioned viewpoint, water is preferably used from the viewpoint of ease of availability and ease of handling. When water is used, a small proportion of an additive that reduces the surface tension of water and increases the surfactant power may be added. It is preferable that this additive does not dissolve the resist film on the wafer and has a negligible effect on the optical coating on the lower surface of the lens. Distilled water is preferably used as the water to be used.

[0197] After the exposure, it is preferable to perform post-exposure baking (PEB) to promote dissociation of acid-dissociable groups of resins and the like by the acid generated from the radiation-sensitive acid generator by exposure in the exposed parts of the resist film. This PEB causes a difference in solubility in a developer between the exposed parts and the unexposed parts. The PEB temperature is usually 50°C to 180°C, and preferably 80°C to 130°C. The PEB time is usually 5 seconds to 600 seconds, and preferably 10 seconds to 300 seconds.

[0198] [Development process] In this step, the resist film exposed in the exposure step is developed. This allows a desired resist pattern to be formed. After development, the resist film is generally washed with a rinse liquid such as water or alcohol, and then dried.

[0199] In the case of alkaline development, examples of the developer used in the development include an alkaline aqueous solution in which at least one of alkaline compounds such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo-[5.4.0]-7-undecene, and 1,5-diazabicyclo-[4.3.0]-5-nonene is dissolved. Among these, an aqueous TMAH solution is preferred, and a 2.38 mass % aqueous TMAH solution is more preferred.

[0200] In the case of organic solvent development, examples of the organic solvent include hydrocarbon solvents, ether solvents, ester solvents, ketone solvents, and alcohol solvents, or solvents containing an organic solvent. Examples of the organic solvent include one or more of the solvents listed as the solvents for the radiation-sensitive resin composition described above. Among these, ester solvents and ketone solvents are preferred. As the ester solvent, acetate solvents are preferred, and n-butyl acetate and amyl acetate are more preferred. As the ketone solvent, chain ketones are preferred, and 2-heptanone is more preferred. The content of the organic solvent in the developer is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and particularly preferably 99% by mass or more. Examples of components other than the organic solvent in the developer include water and silicone oil.

[0201] Examples of development methods include a method in which a substrate is immersed in a tank filled with developer for a certain period of time (dip method), a method in which developer is piled up on the surface of the substrate by surface tension and left to stand for a certain period of time (paddle method), a method in which developer is sprayed onto the substrate surface (spray method), and a method in which developer is continuously dispensed by scanning a developer dispensing nozzle at a constant speed over a substrate rotating at a constant speed (dynamic dispense method). EXAMPLES

[0202] The present invention will now be described in detail with reference to examples, but the present invention is not limited to the following examples. Measurement methods for various physical properties are shown below.

[0203] [Weight average molecular weight (Mw) and number average molecular weight (Mn)] Measurements were performed by gel permeation chromatography (GPC) using Tosoh GPC columns (G2000HXL: 2, G3000HXL: 1, G4000HXL: 1) under the following analytical conditions: flow rate: 1.0 mL / min, elution solvent: THF, sample concentration: 1.0 mass%, sample injection amount: 100 μL, column temperature: 40° C., detector: differential refractometer, with monodisperse polystyrene as the standard. The dispersity (Mw / Mn) was calculated from the measurement results of Mw and Mn.

[0204] [Low molecular weight fraction content] The content (mass%) of the low molecular weight portion of the polymer (portion with a molecular weight of less than 1,000) was measured by high performance liquid chromatography (HPLC) using an HPLC column (Intersil ODS-25 μm, 4.6 mmφ×250 mm, GL Sciences) under the following analytical conditions: flow rate: 1.0 mL / min, elution solvent: acrylonitrile / 0.1 mass% phosphoric acid aqueous solution, sample concentration: 1.0 mass%, sample injection amount: 100 μL, detector: differential refractometer.

[0205] <Polymer synthesis> The monomers used in the synthesis of the polymers are shown below. In the following synthesis examples, unless otherwise specified, parts by mass refer to a value when the total mass of the monomers used is taken as 100 parts by mass, and % by mole refers to a value when the total number of moles of the monomers used is taken as 100 mol %.

[0206] [ka]

[0207] [Synthesis Example 1] Synthesis of polymer (A-1) As monomers, compound (M-1) and compound (M-2) were dissolved in 20 parts by mass of propylene glycol monomethyl ether so that the molar ratio was 45 / 55 to obtain a monomer solution. Similarly, as a polymerization initiator, 13.2 parts by mass of 2,2'-azobis(isobutyric acid)dimethyl was dissolved in 30 parts by mass of propylene glycol monomethyl ether to obtain a polymerization initiator solution.

[0208] As shown in FIG. 1, the sample introduction side was equipped with a T-shaped pipe, a pressure gauge, and a metering pump, and the outlet side was equipped with a needle valve and a recovery container immersed in an ice bath. A coiled tube made of SUS316 (length of the part immersed in the oil bath: 23.7 m, inner diameter: 2.17 mm) was immersed in an oil bath to serve as a reaction field. The oil bath temperature was adjusted to 118°C and kept constant, and the monomer solution and polymerization initiator solution were continuously pumped at flow rates of 3.6 mL / min and 1.4 mL / min, respectively, using separate metering pumps. The reaction was stopped by quenching in the outlet side recovery container to obtain a solution containing polymer (A-1). At this time, the valve opening on the outlet side was adjusted so that the pressure on the sample introduction side was 0.8 MPa, and the pressure was adjusted to a constant pressure. The residence time of the coiled tube immersed in the oil bath (i.e., reaction time) was 17.5 minutes.

[0209] The obtained polymerization solution was diluted so that the amount of propylene glycol monomethyl ether was 300 parts by mass, and then the solution was poured into n-hexane (1,000 parts by mass) to filter off the precipitated white solid. The filtered white solid was washed twice with 100 parts by mass of hexane per 100 parts by mass of the polymerization solution, and then filtered off to purify the polymer. Next, propylene glycol monomethyl ether (150 parts by mass) was added again to the obtained polymer. Furthermore, methanol (150 parts by mass), triethylamine (1.5 molar equivalents relative to the amount of compound (M-1) used) and water (1.5 molar equivalents relative to the amount of compound (M-1) used) were added, and the hydrolysis reaction was carried out for 8 hours while refluxing at the boiling point. After the reaction was completed, the solvent and triethylamine were distilled off under reduced pressure, and the obtained polymer was dissolved in acetone (150 parts by mass). This was dropped into water (2,000 parts by mass) to coagulate, and the resulting white solid was filtered off. It was then dried at 50° C. for 17 hours to obtain a white solid polymer (A-1).

[0210] [Synthesis Example 2] (Synthesis of Polymer (A-2)) Polymer (A-2) was obtained by carrying out the same operations as in Synthesis Example 1, except that compound (M-3) was used as the monomer instead of compound (M-2).

[0211] [Synthesis Example 3] (Synthesis of Polymer (A-3)) Polymer (A-3) was obtained by carrying out the same operations as in Synthesis Example 1, except that compound (M-4) was used as the monomer instead of compound (M-2).

[0212] [Synthesis Example 4] (Synthesis of Polymer (A-4)) A polymerization reaction was carried out in the same manner as in Synthesis Example 1, except that compound (M-5) was used instead of compound (M-1) as a monomer. The obtained polymerization solution was diluted so that the amount of propylene glycol monomethyl ether was 300 parts by mass, and then added to n-hexane (1,000 parts by mass), and the precipitated white solid was filtered off. The filtered white solid was washed twice with 100 parts by mass of hexane per 100 parts by mass of the polymerization solution, and then filtered off. The mixture was then dried at 50° C. for 17 hours to obtain polymer (A-4).

[0213] [Synthesis Example 5] (Synthesis of Polymer (A-5)) A monomer solution containing the compounds (M-5), (M-3), and (M-6) in a molar ratio of 45 / 45 / 10 was used to carry out a polymerization reaction in the same manner as in Synthesis Example 1. The obtained polymerization solution was diluted so that the amount of propylene glycol monomethyl ether was 300 parts by mass, and then added to n-hexane (1000 parts by mass), and the precipitated white solid was filtered off. The filtered white solid was washed twice with 100 parts by mass of hexane per 100 parts by mass of the polymerization solution, and then filtered off. The mixture was then dried at 50° C. for 17 hours to obtain a polymer (A-5).

[0214] [Synthesis Example 6] (Synthesis of Polymer (A-6)) A monomer solution containing the compounds (M-5), (M-2), and (M-7) in a molar ratio of 45 / 45 / 10 was used to carry out a polymerization reaction in the same manner as in Synthesis Example 1. The obtained polymerization solution was diluted so that the amount of propylene glycol monomethyl ether was 300 parts by mass, and then added to n-hexane (1,000 parts by mass), and the precipitated white solid was filtered off. The filtered white solid was washed twice with 100 parts by mass of hexane per 100 parts by mass of the polymerization solution, and then filtered off. The resulting solution was then dried at 50° C. for 17 hours to obtain a polymer (A-6).

[0215] [Comparative Synthesis Example 1] Synthesis of Polymer (B-1) Compound (M-1) and compound (M-2) were dissolved in propylene glycol monomethyl ether (200 parts by mass) as monomers so that the molar ratio between them was 45 / 55. Next, 2,2'-azobis(isobutyrate) dimethyl (12 mol%) was added to this solution as a polymerization initiator to prepare a mixed solution. Propylene glycol monomethyl ether (100 parts by mass) was placed in an empty reaction vessel and heated to 85°C while stirring. The mixed solution prepared above was dripped into this. The start of dripping was set to 0 hours, and the mixed solution was dripped over 3 hours. After the end of dripping, the mixture was heated at 85°C for another 3 hours, and the polymerization reaction was carried out for a total of 6 hours.

[0216] The obtained polymerization solution was poured into n-hexane (1,000 parts by mass), and the precipitated white solid was filtered off. The filtered white solid was washed twice with 100 parts by mass of hexane per 100 parts by mass of the polymerization solution, and then filtered off to purify the polymer. Next, propylene glycol monomethyl ether (150 parts by mass) was added again to the obtained polymer. Furthermore, methanol (150 parts by mass), triethylamine (1.5 molar equivalents relative to the amount of compound (M-1) used) and water (1.5 molar equivalents relative to the amount of compound (M-1) used) were added, and the hydrolysis reaction was carried out for 8 hours while refluxing at the boiling point. After the above reaction was completed, the solvent and triethylamine were distilled off under reduced pressure, and the obtained polymer was dissolved in acetone (150 parts by mass). This was dropped into water (2,000 parts by mass) to coagulate, and the resulting white solid was filtered off. Next, it was dried at 50° C. for 17 hours to obtain a white powder solid polymer (B-1).

[0217] [Comparative Synthesis Example 2] (Synthesis of Polymer (B-2)) A polymer (B-2) was obtained by carrying out the same operations as in Comparative Synthesis Example 1, except that the compound (M-3) was used as the monomer instead of the compound (M-2).

[0218] [Comparative Synthesis Example 3] (Synthesis of Polymer (B-3)) A polymer (B-3) was obtained by carrying out the same operations as in Comparative Synthesis Example 1, except that the compound (M-4) was used as the monomer instead of the compound (M-2).

[0219] [Comparative Synthesis Example 4] (Synthesis of Polymer (B-4)) A polymerization reaction was carried out in the same manner as in Comparative Synthesis Example 1, except that the compound (M-5) was used instead of the compound (M-1) as the monomer. The obtained polymerization solution was poured into n-hexane (1,000 parts by mass), and the precipitated white solid was filtered off. The filtered white solid was washed twice with 100 parts by mass of hexane per 100 parts by mass of the polymerization solution, and then filtered off. The solid was then dried at 50° C. for 17 hours to obtain a polymer (B-4).

[0220] [Comparative Synthesis Example 5] (Synthesis of Polymer (B-5)) A monomer solution containing the compounds (M-5), (M-3), and (M-6) in a molar ratio of 45 / 45 / 10 was used, and polymerization reaction was carried out in the same manner as in Comparative Synthesis Example 1. The obtained polymerization solution was poured into n-hexane (1,000 parts by mass), and the precipitated white solid was filtered off. The filtered white solid was washed twice with 100 parts by mass of hexane per 100 parts by mass of the polymerization solution, and then filtered off. The resulting mixture was then dried at 50° C. for 17 hours to obtain a polymer (B-5).

[0221] [Comparative Synthesis Example 6] (Synthesis of Polymer (B-6)) A monomer solution was prepared containing the compounds (M-5), (M-2), and (M-7) as monomers in a molar ratio of 45 / 45 / 10, and a polymerization reaction was carried out in the same manner as in Comparative Synthesis Example 1. The obtained polymerization solution was poured into n-hexane (1,000 parts by mass), and the precipitated white solid was filtered off. The filtered white solid was washed twice with 100 parts by mass of hexane per 100 parts by mass of the polymerization solution, and then filtered off. The resulting solution was then dried at 50° C. for 17 hours to obtain a polymer (B-6).

[0222] Table 1 shows the Mw, Mw / Mn and resin composition of the polymers (A-1 and B-1) obtained in Synthesis Example 1 and Comparative Synthesis Example 1. The Mw, Mw / Mn and resin composition of A-1 and B-1 were roughly equivalent. [Table 1]

[0223] <Changes in monomer composition over time> Polymers were obtained at each reaction time by the same operation as in Synthesis Example 1, except that the reaction field (length of the SUS coil tube immersed in the oil bath) was changed to 19 m, 14.2 m, 9.3 m, and 4.6 m in Synthesis Example 1. These are regarded as polymer samples during the polymerization reaction in Synthesis Example 1. Meanwhile, in Comparative Synthesis Example 1, sampling was performed at 1 hour, 2 hours, 3 hours, 4 hours, and 5 hours from the start of polymerization. These were analyzed by HPLC, and the monomer composition ratio in the polymer was calculated from the monomer consumption rate. The obtained results are shown in Figure 2. In Figure 2, "normalized reaction time" is the relative reaction time with the time at which Synthesis Example 1 and Comparative Synthesis Example 1 are completed set to 1.0.

[0224] From FIG. 2, it can be seen that in Comparative Synthesis Example 1, a polymer that deviated significantly from the final composition ratio was produced in the early stage of the reaction, resulting in a wide range of monomer composition, whereas in Synthesis Example 1, a polymer with an almost constant composition was obtained from the early stage to the end of the polymerization reaction.

[0225] <Preparation of Radiation-Sensitive Resin Composition> The acid generators (C), acid diffusion controllers (D), and solvents (E) used in the preparation of the radiation-sensitive resin compositions of the Examples and Comparative Examples are shown below.

[0226] [[C] Acid generator] The structural formula is shown below. [ka]

[0227] [[D] Acid diffusion controller] The structural formula is shown below. [ka]

[0228] [[E]solvent] E-1: Propylene glycol monomethyl ether acetate E-2: Propylene glycol monomethyl ether

[0229] [Example 1] 100 parts by mass of (A-1) as the polymer [A], 17 parts by mass of (C-1) as the radiation-sensitive acid generator, 5 parts by mass of (D-1) as the acid diffusion controller [D], and further 2,240 parts by mass of (E-1) and 960 parts by mass of (E-2) as solvents were mixed and filtered through a membrane filter having a pore size of 20 nm, to prepare a radiation-sensitive resin composition (F-1).

[0230] [Examples 2 to 6] (Radiation-sensitive resin compositions (F-2) to (F-6)) Each radiation-sensitive resin composition was prepared in the same manner as in Example 1, except that (A-2) to (A-6) were used as the polymer.

[0231] [Comparative Examples 1 to 6] (Radiation-sensitive resin compositions (F-7) to (F-12)) Each radiation-sensitive resin composition was prepared in the same manner as in Example 1, except that (B-1) to (B-6) were used as the polymer.

[0232] [Table 2]

[0233] <Formation of Resist Pattern> On a 12-inch silicon wafer, a spin coater (Tokyo Electron Limited's "CLEAN TRACK ACT8") was used to apply AL412 (Brewer Science) to a thickness of 20 nm. The radiation-sensitive resin composition prepared above was then applied using the spin coater, and PB was performed at 130°C for 60 seconds. The resist film was then cooled at 23°C for 30 seconds to form an average thickness of 55 nm. Next, this resist film was exposed to light using an EUV exposure device (ASML's "NXE3300") with NA = 0.33, illumination conditions: Conventional s = 0.89, and mask: imecDEFECT32FFR02. After exposure, PEB was performed at 120°C for 60 seconds. The resist film was then alkali-developed using a 2.38 mass% TMAH aqueous solution as an alkaline developer, and after development, it was washed with water and further dried to form a positive resist pattern (32 nm line and space pattern).

[0234] <Evaluation> The defect suppression, sensitivity and LWR performance of the radiation-sensitive resin composition were evaluated by the following methods. A high-resolution FEB length measurement device ("CG5000" manufactured by Hitachi High-Technologies Corporation) was used to measure the length of the resist pattern in terms of sensitivity and LWR performance.

[0235] [Defect suppression] The number of defects per measurement area (pcs / cm2) of the line and space pattern formed above was measured using a defect inspection device (KLA-Tencor's "KLA2925"). The defect suppression ability is evaluated as "good" when it is 100 pcs / cm2 or less, and "poor" when it exceeds 100 pcs / cm2.

[0236] [sensitivity] In forming the above resist pattern, the exposure amount for forming a 32 nm line and space pattern was defined as the optimum exposure amount, and this optimum exposure amount was defined as the sensitivity (mJ / cm2).

[0237] [LWR performance] The 32 nm line and space pattern formed above was observed from above the pattern. The width was measured at 50 random points, and the 3 sigma value was calculated from the distribution of the measured values. This 3 sigma value was taken as the LWR performance (nm). The smaller the LWR performance value, the smaller the line width variation and the better the performance. LWR performance can be evaluated as "good" when it is 3.4 nm or less, and "poor" when it exceeds 3.4 nm.

[0238] [Table 3]

[0239] As can be seen from the results in Table 3 above, each of the radiation-sensitive resin compositions of the Examples afforded resist patterns that were excellent in defect suppression while maintaining sensitivity and LWR performance, as compared to the Comparative Examples in which radiation-sensitive resin compositions having the same monomer composition were used. [Industrial Applicability]

[0240] As described above, the radiation-sensitive resin composition and its production method, as well as the production method of polymer A used therein, etc. of the present invention make it possible to obtain a resist pattern having the same sensitivity and LWR performance as conventional ones and excellent defect suppression. The radiation-sensitive resin composition and its production method, as well as the production method of polymer A used therein, etc. of the present invention can be suitably used for the formation of fine resist patterns in the lithography process of various electronic devices such as semiconductor devices and liquid crystal devices.

Claims

1. A method for producing a polymer, comprising the steps of: obtaining a polymer by radical polymerization in the presence of a monomer having a phenolic hydroxyl group or a protected form thereof and a polymerization initiator, the method comprising the steps of: the radical polymerization is continuously carried out in a flow path including an inlet portion, an outlet portion, and a heating portion provided between the inlet portion and the outlet portion in a unidirectional flow state from the inlet portion to the outlet portion, The flow path has a region of 105°C to 150°C by heating the heating unit, A method for producing a polymer, wherein a content of the monomer having a phenolic hydroxyl group or a protected form thereof is 10 mol % or more and 70 mol % or less of all monomers forming the polymer.

2. The method for producing a polymer according to claim 1 , wherein the monomer having a phenolic hydroxyl group or a protected form thereof is represented by the following formula (1): 【Chemistry 1】 (In the above formula (1), R α is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. L is a single bond, -COO- ＊ Or -O- ＊ * indicates a bond on the aromatic ring side. R １１ R is a hydrogen atom, an acyl group having 2 to 20 carbon atoms, or an alkoxycarbonyl group having 2 to 20 carbon atoms. １１ When there are multiple R １１ are the same or different from each other. R １２ R is a cyano group, a nitro group, an alkyl group, a fluorinated alkyl group, an alkoxycarbonyloxy group, an acyl group, or an acyloxy group. １２ When there are multiple R １２ are the same or different from each other. n １ is an integer from 0 to 2, m １ is an integer from 1 to 8, m ２ is an integer from 0 to 8, provided that 1≦m １ +m ２ ≦2n １ Meets +5.)

3. The method for producing a polymer according to claim 1 , wherein the radical polymerization is carried out further in the presence of a structural unit having an acid-dissociable group.

4. The method for producing a polymer according to claim 3 , wherein the structural unit having an acid-dissociable group is represented by the following formula (2): 【Chemistry 2】 In the above formula (2), R ７ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ８ is a halogen-substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms. R ９ and R １０ each independently represents a halogen-substituted or unsubstituted monovalent linear hydrocarbon group having 1 to 10 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a divalent alicyclic group having 3 to 20 carbon atoms constituted by combining these groups together with the carbon atom to which they are bonded.)

5. The method for producing a polymer according to claim 4, wherein the structural unit having an acid-dissociable group is any one or more of monomers represented by the following formulas (2-1) to (2-6): 【Chemistry 3】 (In the above formulas (2-1) to (2-6), R ７ ~R １０ has the same meaning as formula (2) above. i and j each independently represent an integer from 1 to 4. k and l are 0 or 1.

6. The method for producing a polymer according to claim 4, wherein a content of the structural unit having an acid dissociable group is from 20 mol % to 90 mol % of all monomers forming the polymer.

7. The method for producing a polymer according to claim 1 , wherein the polymer further comprises a monomer having a polar group.

8. The method for producing a polymer according to claim 7 , wherein the content of the monomer having a polar group is from 2 mol % to 40 mol % of all the monomers forming the polymer.

9. A method for producing a radiation-sensitive resin composition, comprising a step of mixing the polymer obtained by the method for producing a polymer according to any one of claims 1 to 8 with a solvent.

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