JP6838863B2 - Resin for photoresist, method for producing photoresist resin, resin composition for photoresist, and method for forming a pattern - Google Patents

Description

The present invention relates to a photoresist resin used for microfabrication of semiconductors, a method for producing the photoresist resin, a photoresist resin composition, and a pattern forming method using the photoresist resin composition.

As a method for producing a photoresist resin composed of a (meth) acrylate polymer, a monomer, a polymerization initiator, and a chain transfer agent, if necessary, are mixed or separately supplied in a system maintained at a polymerization temperature. The so-called dropping polymerization method is generally used. As such a dropping polymerization method, for example, the following dropping polymerization method is known (Patent Documents 1 and 2).
1. Method of preheating the monomer and dropping it 2. Method of dropping the monomer in a polymerization solvent kept at a constant temperature

Generally, when dropping polymerization is used, since the concentration of the polymerization initiator in the system is low at the initial stage of dropping the monomer, a polymer having a higher molecular weight than that at the latter stage of dropping is produced. High molecular weight polymers have low solubility in solvents and can cause foreign matter over time and defects during the exposure process.

The following methods and the like are known as methods for producing a polymer having excellent solvent solubility (Patent Documents 3 and 4).
3. Method for producing a polymer that changes the dropping rate of the monomer solution and / or the polymerization initiator solution in two or more steps 4. Before starting the polymerization, 1 to 50% of the total polymerization initiator is added in advance into the container. How to make a polymer

However, the above methods 3 and 4 are insufficient to suppress the formation of a polymer having a high molecular weight at the initial stage of dropping, except for specific optimized conditions.

In terms of resin production conditions, the production conditions are diverse when pursuing quality improvement represented by production efficiency such as yield and process time and reduction of impurities. On the other hand, no method has yet been found that can easily and surely suppress the formation of high molecular weight at the initial stage of dropping under any conditions.

Japanese Unexamined Patent Publication No. 2004-269855 Japanese Unexamined Patent Publication No. 2004-355023 Patent No. 3720827 Japanese Unexamined Patent Publication No. 2010-168434

Therefore, an object of the present invention is to provide a resin for a photoresist in which the formation of a component having a high molecular weight at the initial stage of dropping is suppressed in the dropping polymerization, and a method for producing the same. Furthermore, an object of the present invention is to provide a photoresist resin composition containing the photoresist resin, and a pattern forming method using the photoresist resin composition.

As a result of diligent studies to achieve the above object, the present inventors have generated a component having a high molecular weight from the initial stage to the final stage of the polymerization reaction in the step of dropping and polymerizing the monomer and the polymerization initiator, thereby performing the initial dropping stage. It was found that the formation of a component having a high molecular weight can be efficiently suppressed. The present invention has been completed based on these findings.

That is, the present invention is a resin for photoresist obtained by radical polymerization of the monomer by a dropping polymerization method in which the monomer and the polymerization initiator are dropped, from the start of the dropping to the end of the dropping. The weight average molecular weight (Mw _tA ) of the polymer produced at an arbitrary time t _A and the weight average molecular weight (Mw _tB ) of _{the polymer produced at an arbitrary time t B} from the start of the dropping to the end of the dropping. Provided is a resin for a photoresist characterized in that when the relationship of t _A <t _B is satisfied, Mw _tA <Mw _tB.

Further, the present invention is a method for producing a resin for a photoresist obtained by radically polymerizing the monomer by a dropping polymerization method in which the monomer and the polymerization initiator are dropped, and after the start of dropping the polymerization initiator. After 10 minutes or more have passed, the monomer is started to be added dropwise, and the concentration of the polymerization initiator in the reaction solution at an _{arbitrary time t C from the start of the addition of the monomer to the end of the addition (I).} and _tC), the relationship between the concentration of the polymerization initiator in the reaction solution (I _tD) at any time t _D between until the completion of the dropwise addition after the t _C is the which is the I _tC> I _tD Provided is a method for producing a resin for a photoresist.

Further, the present invention is a method for producing a resin for photoresist obtained by radical polymerization of the monomer in the presence of a chain transfer agent by a dropping polymerization method in which a monomer and a polymerization initiator are dropped, and the dropping thereof. _{The concentration (C tE} ) of the chain transfer agent in the reaction solution at _{an arbitrary time t E} from the start to the end of the dropping, and at an arbitrary time t _{F between the after t E} and the end of the dropping. Provided is a method for producing the above-mentioned photoresist resin, in which the relationship with the concentration of the chain transfer agent (C _{tF ) in the reaction solution is C tE} > C _tF.

Further, the present invention is a method for producing a resin for photoresist obtained by radical polymerization of the monomer by a dropping polymerization method in which a monomer and a polymerization initiator are dropped, and the dropping amount of the monomer is large. The reaction temperature starts to be lowered when it is less than 15% by weight based on the total amount of the dropping monomer, and the temperature (T ₀ ) at the start of dropping of the monomer and the polymerization initiator and the temperature at the end of dropping (T 0). T ₁₎ relationship with is a T _0> T _1, the temperature of the reaction solution at an arbitrary time t _G between after the dropping start to the completion of the dropwise addition and (T _tG), dropwise after the t _G Provided is the method for producing the above-mentioned photoresist resin, wherein the relationship with the _{temperature (T tH} ) of the reaction solution at an arbitrary time t _{H until the end time is T tG} ≧ T _tH.

The present invention also provides a photoresist resin produced by the above-mentioned production method.

The present invention also provides a photoresist resin composition containing at least the above-mentioned photoresist resin and a radiation-sensitive acid generator.

The present invention also provides a pattern forming method including at least a step of applying the photoresist resin composition to a substrate to form a coating film, exposing the coating film, and then alkali-dissolving the coating film.

According to the resin for photoresist of the present invention, the formation of a component having a high molecular weight at the initial stage of dropping is suppressed in the dropping polymerization, so that the component having a high molecular weight is extremely small in the resin for photoresist. Therefore, when the resin for photoresist of the present invention is used, the polymerization unit that has become alkaline-soluble by the action of an acid has excellent alkali solubility, and a pattern can be formed with high accuracy.

[Resin for photoresist]
The photoresist resin of the present invention has a group (sometimes referred to as an "acid-degradable group") in which a part thereof is eliminated by the action of an acid to form a polar group. As a result, the photoresist resin of the present invention has an increased polarity due to the action of the acid and an increased solubility in an alkaline developer.

Examples of the polar group include a phenolic hydroxyl group, a carboxy group, a fluorinated alcohol group (preferably a hexafluoroisopropanol group), a sulfonic acid group, a sulfonamide group, a sulfonylimide group, and a (alkylsulfonyl) (alkylcarbonyl) methylene group. , (Alkylsulfonyl) (alkylcarbonyl) imide group, bis (alkylcarbonyl) methylene group, bis (alkylcarbonyl) imide group, bis (alkylsulfonyl) methylene group, bis (alkylsulfonyl) imide group, tris (alkylcarbonyl) methylene Examples include acidic groups such as groups and tris (alkylsulfonyl) methylene groups; alcoholic hydroxyl groups and the like. Of these, a carboxy group, a fluorinated alcohol group (preferably a hexafluoroisopropanol group), and a sulfonic acid group are preferable.

As the acid-degradable group, a group in which the hydrogen atom of the polar group is replaced with a group desorbing with an acid is preferable. Examples of the acid-degradable group include -C ( ^RI ) (R ^II ) (R ^III ), -C (R ^IV ) (R ^V ) (OR ^VI ) and the like. In the above formulas, R ^I ~R ^III, R ^VI each independently represents an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or an alkenyl group. R ^IV and R ^V each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or an alkenyl group. At least two of the radicals R ^I to R ^III may be bonded to each other to form a ring. Further, R ^IV and R ^V may be combined with each other to form a ring.

The number of carbon atoms of the acid-degradable group is not particularly limited, but is preferably 4 or more, and more preferably 5 or more. The upper limit of the number of carbon atoms is not particularly limited, but 20 is preferable.

Alkyl groups of R ^I to R ^VI is preferably an alkyl group having 1 to 8 carbon atoms, e.g., cyclohexyl methyl group, an ethyl group, a propyl group, n- butyl group, s- butyl, t- butyl group to, Groups, octyl groups and the like can be mentioned.

The cycloalkyl group R ^I to R ^VI can be a monocyclic hydrocarbon group, a polycyclic (bridged cyclic) may be a hydrocarbon group. The monocyclic hydrocarbon group is preferably a cycloalkyl group having 3 to 8 carbon atoms, and examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group and a cyclooctyl group. The polycyclic hydrocarbon group is preferably a cycloalkyl group having 6 to 20 carbon atoms, for example, an adamantyl group, a norbornyl group, an isobolonyl group, a camphanyl group, a dicyclopentyl group, an α-pinel group, a tricyclodecanyl group, and the like. Examples thereof include a tetracyclododecyl group and an androstanyl group. In addition, at least one carbon atom in the cycloalkyl group may be substituted with a hetero atom such as an oxygen atom.

The aryl group for R ^I to R ^VI is preferably an aryl group having 6 to 14 carbon atoms, for example, a phenyl group, a naphthyl group, an anthryl group.

Aralkyl groups of R ^I to R ^VI is preferably an aralkyl group having 7 to 12 carbon atoms, for example, benzyl group, phenethyl group, etc. naphthylmethyl group.

Alkenyl groups of R ^I to R ^VI is preferably an alkenyl group having 2 to 8 carbon atoms, e.g., vinyl group, allyl group, butenyl group, hexenyl group and the like cyclohexylene.

The R ^I to R ring in which at least two groups are bonded to each other to form one of ^III, and a ring and R ^IV and R ^V are formed by combining the cycloalkane ring. The cycloalkane ring includes a monocyclic cycloalkane ring such as a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, and a cyclohexane ring; a polycyclic type such as a norbornane ring, a tricyclodecane ring, a tetracyclododecane ring, and an adamantan ring. Cycloalkane ring is preferred.

The alkyl group in R ^I to R ^VI, cycloalkyl group, aryl group, aralkyl group, alkenyl group, and the cycloalkane ring may each have a substituent.

As the acid-degradable group, among them, a t-butyl group, a t-amyl group, and a group represented by the following formulas (I) to (IV) are preferable.

The formula ^{(I) ~ R 2 ~R 7} , R a, n, p, and ring Z ¹ in (IV), respectively, the formula below (a1) in ^{~ (a4) R 2 ~R 7} , The same as R ^a , n, p, and ring Z ¹ is shown.

The acid-degradable group may be provided via a spacer. The spacer is the same as the linking group exemplified and described as A in the formula (1) described later.

The photoresist resin of the present invention preferably contains an acid-degradable group as a polymerization unit having an acid-degradable group. Examples of the polymerization unit having such an acid-decomposable group include a polymerization unit represented by the following formula (1).

In the above formula (1), R ¹ represents the above acid-degradable group. Further, in the above formula (1), R represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom. Examples of the halogen atom include a chlorine atom, a bromine atom, an iodine atom and the like. Examples of the alkyl group having 1 to 6 carbon atoms include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, pentyl, isoamyl, s-amyl, t-amyl and hexyl groups. And so on. As the alkyl group having 1 to 6 carbon atoms having a halogen atom, one or two or more hydrogen atoms constituting the above alkyl group such as trifluoromethyl and 2,2,2-trifluoroethyl group are halogen atoms. Substituted groups (halo (C _1-6 ) alkyl groups) and the like can be mentioned.

In the above formula (1), A represents a single bond or a linking group. Examples of the linking group include a carbonyl group (-C (= O)-), an ether bond (-O-), an ester bond (-C (= O) -O-), and an amide bond (-C (= O)). ) -NH-), carbonate bond (-OC (= O) -O-), a group in which a plurality of these are linked, an alkylene group and a group in which these are bonded, and the like can be mentioned. Examples of the alkylene group include a linear or branched alkylene group such as methylene, methylmethylene, dimethylmethylene, ethylene, propylene and trimethylene, 1,2-cyclopentylene and 1,3-cyclopenti. Divalent alicyclic hydrocarbon groups such as len, cyclopentylidene, 1,2-cyclohexylene, 1,3-cyclohexylene, 1,4-cyclohexylene, cyclohexylidene group (particularly divalent). Cycloalkylene group) and the like.

The polymerization unit represented by the above formula (1) preferably contains at least one polymerization unit selected from the group consisting of the polymerization units represented by the following formulas (a1) to (a4). The "at least one polymerization unit selected from the group consisting of the polymerization units represented by the formulas (a1) to (a4)" may be referred to as "monomer unit a".

In the polymerization unit represented by the above formulas (a1) to (a4), R has the same number of carbon atoms as R in the above formula (1), which may have a hydrogen atom, a halogen atom, or a halogen atom. It represents alkyl groups 1-6, where A represents a single bond or linking group. As A in the above formulas (a1) to (a4), a single bond or a group in which an alkylene group and a carbonyloxy group are bonded (alkylene-carbonyloxy group) is preferable. R ^{2 to} R ⁴ indicate the same or different alkyl groups having 1 to 6 carbon atoms which may have a substituent. R ⁵ and R ⁶ indicate the same or different alkyl groups having 1 to 6 carbon atoms which may have a hydrogen atom or a substituent. R ⁷ indicates a −COOR ^c group, and the above R ^c indicates a tertiary hydrocarbon group, a tetrahydrofuranyl group, a tetrahydropyranyl group, or an oxepanyl group which may have a substituent. n represents an integer of 1 to 3. R ^a is a substituent bound to Ring Z ^1, same or different, oxo group, an alkyl group, which may be protected by a hydroxy group with a protecting group, may be protected by a protecting group hydroxy Indicates a carboxyl group that may be protected by an alkyl group or a protective group. p represents an integer from 0 to 3. Ring Z ¹ represents an alicyclic hydrocarbon ring having 3 to 20 carbon atoms.

Examples ^{of the alkyl group in Ra} include carbons such as methyl, ethyl, propyl, isopropyl, n-butyl, s-butyl, t-butyl, pentyl, isoamyl, s-amyl, t-amyl and n-hexyl groups. Alkyl groups of numbers 1 to 6 and the like can be mentioned.

Examples of the hydroxyalkyl group in R ^a, for example, hydroxymethyl, 2-hydroxyethyl, 1-hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl, 4-hydroxybutyl, etc. 6-hydroxyhexyl group hydroxy C _{1 -6} Alkyl groups and the like can be mentioned.

Examples ^{of the hydroxy group in Ra} and the protective group that the hydroxyalkyl group may have include a C _1-4 alkyl group such as a methyl, ethyl, and t-butyl group; together with an oxygen atom constituting the hydroxy group. group forming an acetal bond (e.g., C _1-4 alkyl -O-C _1-4 alkyl group such as methoxymethyl group); groups to form ester bond with an oxygen atom constituting a hydroxyl group (e.g., acetyl group, Bencoyl group, etc.) and the like can be mentioned.

Examples ^{of the carboxy group protecting group in Ra} include methyl, ethyl, propyl, isopropyl, n-butyl, s-butyl, t-butyl, pentyl, isoamyl, s-amyl, t-amyl, and hexyl groups. C _1-6 alkyl group; 2-tetrahydrofuranyl group, 2-tetrahydropyranyl group, 2-oxepanyl group and the like can be mentioned.

Examples ^{of the alkyl group having 1 to 6 carbon atoms in R 2 to} R 6 include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, pentyl, isoamyl, and s-amyl. Examples thereof include linear or branched alkyl groups such as t-amyl and hexyl groups. In the present invention, a C _1-4 alkyl group is preferable, a C _1-3 alkyl group is particularly preferable, and a _{C 1-2} alkyl group is most preferable.

Examples of the ^{substituent that the alkyl group having 1 to 6 carbon atoms in R 2 to} R 6 may have include a halogen atom, a hydroxy group, and a substituted hydroxy group (for example, C _{1 such as methoxy, ethoxy, and propoxy group). -4} Alkyl group, etc.), cyano group, etc. can be mentioned. As the alkyl group having 1 to 6 carbon atoms having a substituent, for example, one or two or more hydrogen atoms constituting the above alkyl group such as trifluoromethyl and 2,2,2-trifluoroethyl group are halogen. Atomatically replaced halo (C _1-6 ) alkyl groups; hydroxymethyl, 2-hydroxyethyl, methoxymethyl, 2-methoxyethyl, ethoxymethyl, 2-ethoxyethyl, cyanomethyl, 2-cyanoethyl groups and the like. it can.

Examples ^{of the tertiary hydrocarbon group in R c} include a t-butyl group and a t-amyl group.

Examples ^{of the substituent that the tertiary hydrocarbon group in R c} may have include a halogen atom, a hydroxy group, and a substituted hydroxy group (for example, a C _1-4 alkoxy group such as methoxy, ethoxy, and propoxy group). Etc.), cyano group and the like.

The alicyclic hydrocarbon ring having 3 to 20 carbon atoms in the ring Z ¹ includes, for example, 3 to 20 members (preferably 3 to 20) such as a cyclopropane ring, a cyclobutene ring, a cyclopentane ring, a cyclohexane ring, and a cyclooctane ring. Cycloalkane ring of about 15 members, particularly preferably 5 to 12 members; 3 to 20 members (preferably 3 to 15 members, particularly preferably 5 to 10 members) of cyclopropene ring, cyclobutene ring, cyclopentene ring, cyclohexene ring and the like. ) Monocyclic alicyclic hydrocarbon ring such as cycloalkene ring; adamantan ring; norbornane ring, norbornene ring, bornan ring, isobornane ring, tricyclo [5.2.1.0 ^2,6 ] decane ring, tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] Norbornane ring such as dodecane ring or ring containing norbornene ring; perhydroinden ring, decalin ring (perhydronaphthalene ring), perhydrofluorene ring (tricyclo [7.4.0.0 ^3,8 ] Tridecane ring), a ring in which a polycyclic aromatic fused ring such as a perhydroanthracene ring is hydrogenated (preferably a completely hydrogenated ring); a tricyclo [4.2.2.1 ^2,5 ] undecane ring, etc. A bridged hydrocarbon ring having about 2 to 6 rings such as a bridging hydrocarbon ring having a 2-ring system, a 3-ring system, or a 4-ring system (for example, a bridging hydrocarbon ring having about 6 to 20 carbon atoms). And so on.

Specific examples of the monomer unit a include a monomer unit represented by the following formula. In the monomer unit represented by the following formula, R ^d represents a methyl group or a hydrogen atom, and R ^e represents a methyl group or a hydrogen atom. ^{Further, the bonding position of R e} to the alicyclic hydrocarbon ring is not particularly limited, and one or a plurality of R ^e are bonded to any of the carbon atoms constituting the alicyclic hydrocarbon ring. You may. Monomer unit represented by the following formula, when having R ^e 2 or more, two or more of said R ^e, respectively, may be different and may be the same. The monomer unit a can be introduced into the photoresist resin by subjecting the corresponding unsaturated carboxylic acid ester to the polymerization.

As the polymerization unit represented by the above formula (1), in addition to the polymerization unit represented by the above-mentioned monomer unit a, an oxygen atom constituting an ester bond is bonded to the β-position of the lactone ring and the α-position of the lactone ring. It is also possible to use a polymerization unit corresponding to an unsaturated carboxylic acid ester containing a lactone ring having at least one hydrogen atom (excluding the polymerization unit corresponding to the monomer unit b described later) or the like.

The polymerization unit represented by the above formula (1) may be only one kind or a combination of two or more kinds. The polymerization unit represented by the above formula (1) preferably contains at least one polymerization unit selected from the group consisting of the polymerization units represented by the above formulas (a1) to (a4). The polymerization unit represented by the above formula (1) is at least one polymerization unit selected from the group consisting of the polymerization units represented by the above formulas (a1) to (a4) and the above formula (a1). Polymerization units represented by the above formula (1) other than at least one polymerization unit selected from the group consisting of polymerization units represented by (a4) (other polymerization units represented by the formula (1)). It may be used in combination with. The polymerization unit represented by the other formula (1) is represented by the formula (1) in which R ¹ is a group having a tertiary hydrocarbon group (for example, t-butyl group, t-amyl group, etc.). The polymerization unit to be used is preferable.

Further, the photoresist resin of the present invention is [-C (= O) -O-], [-S (= O) _2- O-], or [-C (= O) -OC (=). It is preferable to include an alicyclic skeleton having at least O)-]. When the alicyclic skeleton is included, high substrate adhesion and etching resistance can be imparted to the photoresist resin. A fat having at least [-C (= O) -O-], [-S (= O) _2- O-], or [-C (= O) -OC (= O)-]. A polymerization unit containing a cyclic skeleton may be referred to as a "monomer unit b".

The monomer unit b preferably contains at least one polymerization unit selected from the group consisting of polymerization units represented by the following formulas (b1) to (b5). In the formula, R represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, and A represents a single bond or a linking group. X represents an unbonded, methylene group, ethylene group, oxygen atom, or sulfur atom. Y represents a methylene group or a carbonyl group. Z is an alkylene group exemplified and described as a divalent organic group (for example, an alkylene group that may be contained in A in the polymerization unit represented by the formulas (a1) to (a4) (particularly, the number of carbon atoms). 1 to 3 linear alkylene groups), etc.) are shown. V ^{1 to} V ³ _{indicate -CH 2-} , [-C (= O)-], or [-C (= O) -O-], which are the same or different. However, ^{at least one of V 1 to} V ³ is [-C (= O) -O-]. R ^{8 to} R ¹⁴ are the same or different, and may have a hydrogen atom, a fluorine atom, an alkyl group which may have a fluorine atom, a hydroxy group which may be protected by a protecting group, and may be protected by a protecting group. Indicates a good hydroxyalkyl group, a carboxy group that may be protected with a protecting group, or a cyano group.

Examples of R and A in the polymerization units represented by the formulas (b1) to (b5) include the same examples as R and A in the polymerization units represented by the formulas (a1) to (a4). .. ^{Further, the alkyl group in R 8 to} R ¹⁴ in the polymerization unit represented by the formulas (b1) to (b5), the hydroxy group which may be protected by a protecting group, and the hydroxyalkyl which may be protected by a protecting group. Examples of the group and the carboxy group that may be protected by the protecting group include the same examples as those in ^{Ra in the polymerization unit represented by the formulas (a1) to (a4).}

Examples of the ^{alkyl group having a fluorine atom in R 8 to} R ¹⁴ include one or two or more hydrogen atoms constituting the alkyl group such as trifluoromethyl and 2,2,2-trifluoroethyl group. Examples include a group [fluoro (C _1-6 ) alkyl group] replaced with a fluorine atom.

Among the polymerization units represented by the above formulas (b1) to (b4), the above R ^{8 to} R ¹¹ may have one or two or more, respectively, and 1 to 3 are preferable. Furthermore, during the polymerization unit represented by the formula (b1) ~ (b4), if having the R ⁸ to R ¹¹ 2 or more, two or more of the R ⁸ to R ¹¹ are each, the same It may or may not be different.

Among the monomer units b, it is represented by the formula (b1), and R ⁸ is an electron-withdrawing group such as a cyano group, a group having an amide group, a group having an imide group, or a fluoro (C _{1-6) alkyl group.} A certain polymerization unit, a polymerization unit represented by the formula (b2), a polymerization unit represented by the formula (b3) and Y is a carbonyl group, a polymerization unit represented by the formula (b4), and a polymerization unit represented by the formula (b5). The represented polymerization unit can impart excellent substrate adhesion and etching resistance to the resin for photoresist, and also have excellent solubility in an alkaline developing solution, and can form a fine pattern with high accuracy. It is preferable in that it can be done.

In the above formula (b1), when R ⁸ is an electron-withdrawing group such as a cyano group, a group having an amide group, a group having an imide group, or a fluoro (C _1-6 ^{) alkyl group, the above R 8} is It is particularly preferable that the carbon atom marked with * in the formula (b1) is at least bonded.

Specific examples of the monomer unit b include a polymerization unit represented by the following formula. In the monomer unit represented by the following formula, R ^d represents a methyl group or a hydrogen atom. The monomer unit b can be introduced into the photoresist resin by subjecting the corresponding unsaturated carboxylic acid ester to the polymerization.

The photoresist resin of the present invention may further have a monomer unit c. The monomer unit c is a polymerization unit represented by the following formula (c1). When the photoresist resin of the present invention has the monomer unit c as the polymerization unit, higher transparency and etching resistance can be imparted to the photoresist resin. In the formula, R represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom. A represents a single bond or a linking group. R ^b represents a hydroxy group that may be protected by a protecting group, a hydroxyalkyl group that may be protected by a protecting group, a carboxy group that may be protected by a protecting group, or a cyano group, among which hydroxy groups. , Cyan groups are preferred. q indicates an integer of 1 to 5. Ring Z ² represents an alicyclic hydrocarbon ring having 6 to 20 carbon atoms.

Examples of R and A in the polymerization unit represented by the formula (c1) include the same examples as R and A in the polymerization unit represented by the formulas (a1) to (a4). ^{Further, a hydroxy group which may be protected by a protecting group at R b} in the polymerization unit represented by the formula (c1), a hydroxyalkyl group which may be protected by a protecting group, or a hydroxyalkyl group which may be protected by a protecting group may be protected. ^{Examples of a} good carboxy group include the same examples as those in Ra in the polymerization unit represented by the formulas (a1) to (a4).

^{Ring Z 2} in the polymerization unit represented by the formula (c1) represents an alicyclic hydrocarbon ring having 6 to 20 carbon atoms, and is, for example, 6 to 20 members (preferably 6 to 6 to 6) such as a cyclohexane ring and a cyclooctane ring. A cycloalkane ring having about 15 members, particularly preferably 6 to 12 members; a monocycle such as a cycloalkene ring having about 6 to 20 members (preferably 6 to 15 members, particularly preferably 6 to 10 members) such as a cyclohexene ring. Alicyclic hydrocarbon ring; adamantan ring; norbornane ring, norbornene ring, bornan ring, isobornane ring, tricyclo [5.2.1.0 ^2,6 ] decane ring, tetracyclo [4.4.0.1 ^{2, 5} . 1 ^7,10 ] Norbornane ring such as dodecane ring or ring containing norbornene ring; perhydroinden ring, decalin ring (perhydronaphthalene ring), perhydrofluorene ring (tricyclo [7.4.0.0 ^3,8 ] Tridecane ring), a ring in which a polycyclic aromatic fused ring such as a perhydroanthracene ring is hydrogenated (preferably a completely hydrogenated ring); a tricyclo [4.2.2.1 ^2,5 ] undecane ring, etc. A bridged hydrocarbon ring having about 2 to 6 rings such as a bridging hydrocarbon ring having a 2-ring system, a 3-ring system, or a 4-ring system (for example, a bridging hydrocarbon ring having about 6 to 20 carbon atoms). And so on. The ring Z ² is preferably a norbornane ring, a ring containing a norbornene ring, or an adamantane ring.

Specific examples of the monomer unit c include a polymerization unit represented by the following formula. In the polymerization unit represented by the following formula, R ^d represents a methyl group or a hydrogen atom. The monomer unit c can be introduced into the photoresist resin by subjecting the corresponding unsaturated carboxylic acid ester to the polymerization.

The photoresist resin of the present invention preferably has at least the above-mentioned monomer unit a and the above-mentioned monomer unit b, and more preferably at least the above-mentioned monomer unit a, the above-mentioned monomer unit b, and the above-mentioned monomer unit c. In this case, in the photoresist resin of the present invention, the content of the monomer unit a is, for example, about 5 to 95 mol%, preferably 10 with respect to all the monomer units (polymerization units) constituting the photoresist resin. It is ~ 90 mol%, particularly preferably 20-80 mol%, most preferably 30-70 mol%. The content of the monomer unit b is, for example, about 5 to 95 mol%, preferably 10 to 90 mol%, particularly preferably 20 to 80 mol%, most preferably, with respect to all the monomer units constituting the photoresist resin. It is preferably 30 to 70 mol%. Further, the content of the monomer unit c is, for example, about 40 mol% or less, preferably 30 mol% or less, and particularly preferably 20 mol% or less, based on all the monomer units constituting the photoresist resin. The lower limit of the content of the monomer unit c may be 0 mol%.

The weight average molecular weight (Mw) of the photoresist resin of the present invention is, for example, about 1000 to 50,000, preferably 2000 to 20000, particularly preferably 3000 to 15000, and the molecular weight distribution (weight average molecular weight and number average molecular weight). Ratio: Mw / Mn) is, for example, about 1.0 to 3.0, preferably 1.0 to 2.5. In the present specification, the weight average molecular weight (Mw) and the number average molecular weight (Mn) are not particularly limited, but can be measured by, for example, GPC using polystyrene as a standard substance.

[Method for producing a photoresist resin of the present invention]
The photoresist resin of the present invention is obtained by radical polymerization in which the monomer is radically polymerized in the presence of the polymerization initiator by a dropping polymerization method in which the monomer and the polymerization initiator are dropped. That is, the method for producing a photoresist resin of the present invention includes at least a drop polymerization step of radically polymerizing the monomer by a drop polymerization method in which a monomer and a polymerization initiator are dropped. Further, in the above-mentioned dropping polymerization method, the weight average molecular weight (Mw _{tA ) of the produced polymer at an arbitrary time t A} from the start of the dropping to the end of the dropping and the period from the start of the dropping to the end of the dropping relationship between the weight average molecular weight of the polymer produced at an arbitrary time t _B (Mw _tB) of, when satisfying t _a <t _B, a Mw _tA <Mw _tB. Therefore, since the photoresist resin of the present invention is produced from a component having a low molecular weight from the start of polymerization to the end of dropping, the production of a component having a high molecular weight is suppressed.

In the above-mentioned dropping polymerization method, the dropping monomer may be dropped as a liquid containing the monomer (for example, a monomer solution). The same applies to the dropping polymerization initiator. Further, the monomer and the polymerization initiator may be added dropwise independently, or the mixed liquid containing the monomer and the polymerization initiator may be added dropwise.

The t _A is an arbitrary time between the start of dropping the monomer and the polymerization initiator and the end of dropping. The t _B is an arbitrary time from the start of dropping the monomer to the end of dropping. It should be noted that the above t _A and the above t _B have a relationship of “t _A <t _B”. Further, the above-mentioned "after the start of dropping" is after the start of dropping the monomer and the polymerization initiator when the dropping of the monomer and the polymerization initiator is started at the same time, and the dropping of each of the monomer and the polymerization initiator is performed. If the start time is different, it is after the start of dropping of the component that started dropping later. Further, the above-mentioned "at the end of dropping" means the end of dropping of the monomer and the polymerization initiator when the dropping of the monomer and the polymerization initiator ends at the same time, and the dropping of each of the monomer and the polymerization initiator is performed. If the end time is different, it is the time when the dropping of the component whose dropping is completed later is completed.

In the drop polymerization method, the relationship between the weight average molecular weight (Mw _tA ) of _{the polymer produced at the time t A} and the weight average molecular weight (Mw _{tB ) of the polymer produced at the time t B is Mw tA} <Mw _tB. Is. That is, from the start of dropping to the end of dropping, _{the relationship of "Mw tA} <Mw _tB " is always established, and a polymer having a large weight average molecular weight is not produced at the initial stage of the polymerization reaction, and as the polymerization reaction proceeds, The weight average molecular weight of the polymer produced increases.

The Mw _tA and the Mw _tB are preferably smaller than the polymerization average molecular weight of the photoresist resin of the present invention, and the upper limit thereof is not particularly limited, but is preferably 20000, more preferably 15000, and further preferably 10000. .. Since _{the lower limit of Mw tA} is the weight average molecular weight at an arbitrary time from the start of dropping, it is not particularly limited as long as it exceeds the molecular weight of the monomer. On the other hand, the lower limit of _{Mw tB} is not particularly limited as long as it exceeds _{Mw tA.}

The dropping may be continuous dropping (dropping over a certain period of time) or intermittent dropping (dropping in a plurality of times).

In the above-mentioned drop polymerization method, the polymerization initiator may be present in advance in the polymerization solvent before the start of dropping of the monomer or the polymerization initiator, in addition to the polymerization initiator to be dropped.

As the above-mentioned monomer, a known radically polymerizable monomer can be used, and for example, a simple element corresponding to the polymerization unit exemplified and described as the polymerization unit of the photoresist resin of the present invention described above. Quantities can be mentioned. As the polymerization initiator, a known radical polymerization initiator can be used, and examples thereof include azo compounds, peroxide compounds, and redox compounds, and in particular, dimethyl-2,2'-azobis. Isobutyrate, azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), t-butylperoxypivalate, di-t-butyl peroxide, iso-butyryl peroxide, lauroylper Azoides, succinic acid peroxides, dicinnamyl peroxides, di-n-propylperoxydicarbonates, t-butylperoxyallyl monocarbonates, benzoyl peroxides, hydrogen peroxides, ammonium persulfates and the like are preferable. The amount of the polymerization initiator used may be any amount necessary to obtain a polymer having a desired weight average molecular weight, for example, 0.001 to 120 mol, preferably 0, per 1 mol of the monomer mixture. It is about 0.01 to 20 mol.

The total dropping time of the monomer to be dropped and the polymerization initiator (time from the start of dropping to the end of dropping) varies depending on the polymerization temperature, the type of monomer, etc., but is generally 1 to 10 hours, preferably. Is about 2 to 9 hours, more preferably about 3 to 8 hours.

The temperature of the dropping monomer is preferably 40 ° C. or lower. When the monomer is 40 ° C. or lower, it tends to be more difficult to form a polymer having an excessively large molecular weight at the initial stage of the reaction. Further, the liquid containing the monomer may crystallize if it is cooled too much depending on the type of the monomer. Therefore, the temperature of the dropping monomer is more preferably in the range of −10 to 40 ° C.

Examples of the polymerization solvent used for dropping polymerization include glycol-based solvents, ester-based solvents, ketone-based solvents, ether-based solvents, amide-based solvents, sulfoxide-based solvents, monovalent alcohol-based solvents, hydrocarbon-based solvents, and mixed solvents thereof. And so on. Glycol-based solvents include, for example, propylene glycol-based solvents such as propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, and polypropylene glycol; ethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether, and ethylene glycol monoethyl ether. Examples thereof include ethylene glycol-based solvents such as acetate, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate, and polyethylene glycol. Examples of the ester solvent include a lactic acid ester solvent such as ethyl lactate; a propionic acid ester solvent such as methyl 3-methoxypropionate; and an acetate solvent such as methyl acetate, ethyl acetate, propyl acetate and butyl acetate. .. Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone, cyclopentanone, cyclohexanone and the like. Examples of the ether solvent include chain ethers such as diethyl ether, diisopropyl ether, dibutyl ether and dimethoxyethane; cyclic ethers such as tetrahydrofuran and dioxane. Examples of the amide solvent include N, N-dimethylformamide and the like. Examples of the sulfoxide solvent include dimethyl sulfoxide and the like. Examples of the monohydric alcohol solvent include methanol, ethanol, propanol, isopropyl alcohol, butanol and the like. Examples of the hydrocarbon solvent include aliphatic hydrocarbons such as pentane, hexane, heptane and octane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; aromatic hydrocarbons such as benzene, toluene and xylene.

Preferred polymerization solvents include glycol solvents such as propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate; ester solvents such as ethyl lactate; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone, cyclopentanone and cyclohexanone. System solvents; and mixed solvents thereof.

In the dropping polymerization, the ratio of the amount of the solvent to be charged in advance and the total amount of the dropping liquid (the total amount of the dropping monomer, the polymerization initiator, and the solvent) is the productivity, economy, workability, operability, etc. The quality of the resin can be appropriately set within a range that does not impair the quality of the resin, but in general, the former / the latter (weight ratio) = 5/95 to 90/10, preferably 10/90 to 70/30, and more preferably. It is in the range of 20/80 to 60/40. The total amount of the polymerization solvent to be used (the amount of the solvent prepared in advance + the amount of the solvent in the liquid to be dropped) can be appropriately selected in consideration of workability, operability, reaction efficiency, solubility of the polymer to be produced, and the like. Generally, it is about 100 to 2000 parts by weight, preferably 200 to 1000 parts by weight, and more preferably about 200 to 500 parts by weight with respect to 100 parts by weight of the total amount of the monomer.

A chain transfer agent may be used in the above drop polymerization method. As the chain transfer agent, a known chain transfer agent used for radical polymerization can be used, and for example, a thiol (n-dodecyl mercaptan, n-octyl mercaptan, n-butyl mercaptan, tert-butyl mercaptan, n) can be used. -Lauryl mercaptan, mercaptoethanol, mercaptopropanol, triethylene glycol dimercaptan, etc.), thiol acid and its esters (mercaptopropionic acid, thiobenzoic acid, thioglycolic acid, thioapple acid, etc., and alkyl esters thereof, etc.), alcohol ( Isopropyl alcohol, etc.), amine (dibutylamine, etc.), hypophosphite (sodium hypophosphate, etc.), α-methylstyrene dimer, turbinolene, milsen, limonene, α-pinene, β-pinene, etc. The amount of the chain transfer agent is preferably 0.001 to 3% by weight with respect to the amount of the total radically polymerizable monomer (100% by weight).

The polymerization temperature is not particularly limited, but is, for example, about 30 to 150 ° C., preferably 50 to 120 ° C., and more preferably 60 to 100 ° C.

In the dropping polymerization, a aging time may be provided after the dropping is completed. The aging time is not particularly limited, but is, for example, about 0.5 to 10 hours, preferably about 1 to 15 hours.

The polymer produced by drop polymerization can be isolated by precipitation (including reprecipitation). For example, a polymerization solution (polymer dope) is added in a solvent (precipitation solvent) to precipitate the polymer, or the polymer is dissolved again in a suitable solvent and this solution is added in the solvent (reprecipitation solvent). The desired polymer can be obtained by reprecipitation or by adding a solvent (reprecipitation solvent or polymerization solvent) to the polymerization solution (polymer dope) and diluting. The precipitation or reprecipitation solvent may be either an organic solvent or water, or may be a mixed solvent.

As the solvent used as the precipitation or reprecipitation solvent, a well-known or conventional solvent can be used. Further, the organic solvent used as the precipitation or reprecipitation solvent may be the same solvent as the polymerization solvent or may be a different solvent. Examples of the organic solvent used as the precipitation or reprecipitation solvent include the organic solvents exemplified as the above-mentioned polymerization solvents (glycol-based solvent, ester-based solvent, ketone-based solvent, ether-based solvent, amide-based solvent, sulfoxide-based solvent, monovalent alcohol. System solvent, hydrocarbon solvent); Halogenized hydrocarbon (halogenated aliphatic hydrocarbon such as methylene chloride, chloroform, carbon tetrachloride; halogenated aromatic hydrocarbon such as chlorobenzene and dichlorobenzene); nitro compound (nitromethane) , Nitroethane, etc.); Nitrile (acetoform, benzonitrile, etc.); Carbonate (dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, etc.); Carous acid (acetic acid, etc.); Mixed solvent containing these solvents and the like.

Among them, at least hydrocarbons (particularly aliphatic hydrocarbons such as hexane and heptane) or alcohols (particularly methanol, ethanol, propanol, isopropyl alcohol, butanol, etc.) are contained as the organic solvent used as the precipitation or reprecipitation solvent. Solvents are preferred. In such a solvent containing at least a hydrocarbon, the ratio of the hydrocarbon (for example, an aliphatic hydrocarbon such as hexane or heptane) to another solvent (for example, esters such as ethyl acetate) is, for example, the former / the latter. (Volume ratio; 25 ° C.) = 10/90 to 99/1, preferably the former / the latter (volume ratio: 25 ° C.) = 30/70 to 98/2, more preferably the former / the latter (volume ratio: 25 ° C.) = About 50/50 to 97/3.

Further, as the organic solvent used as the precipitation or reprecipitation solvent, a mixed solvent of alcohol (particularly methanol) and water, and a mixed solvent of glycol-based solvent (particularly polyethylene glycol) and water are also preferable. In this case, the ratio (volume ratio; 25 ° C.) of the organic solvent (alcohol or glycol-based solvent) to water is, for example, the former / the latter (volume ratio; 25 ° C.) = 10/90 to 99/1, preferably the former / The latter (volume ratio: 25 ° C.) = 30/70 to 98/2, more preferably the former / latter (volume ratio: 25 ° C.) = 50/50 to 97/3.

If necessary, the polymer obtained by precipitation (including reprecipitation) is subjected to a rinsing treatment or a treatment in which the polymer is loosened with a solvent and dispersed while being stirred and washed (sometimes referred to as "repulp treatment"). Attached. Rinse treatment may be performed after the repulp treatment. By repulping or rinsing the polymer produced by the polymerization with a solvent, residual monomers and low molecular weight oligomers adhering to the polymer can be efficiently removed.

In the present invention, among them, at least hydrocarbons (particularly aliphatic hydrocarbons such as hexane and heptane) or alcohols (particularly methanol, ethanol, propanol and isopropyl alcohol) or alcohols (particularly methanol, ethanol, propanol and isopropyl alcohol) as the organic solvent used as the above-mentioned repulp treatment and rinse treatment solvent , Butanol, etc.) is preferred.

Of photoresist resin obtained by the above dropping polymerization, the number-average molecular weight of the polymer produced in the t _A and Mn _tA, the number average molecular weight of the polymer produced in the t _B When Mn _tB, the molecular weight of t _A The distribution (Mw _tA / Mn _tA ) and the molecular weight distribution (Mw _tB / Mn _{tB ) at t B} are, for example, preferably 1.0 to 3.0, more preferably 1.0 to 2.5, respectively.

The degree of polymerization of the photoresist resin at the end of the dropping is not particularly limited, but is preferably 60 or more, more preferably 70 or more, and further preferably 80 or more. When the degree of polymerization at the end of dropping is 60 or more, components having a low molecular weight tend to be difficult to remain.

At the end of the dropping, the content of the low molecular weight (for example, 500 or less, preferably 300 or less) component is not particularly limited, but is 40% by weight or less with respect to the total weight (100% by weight) of the monomer. It is preferable, more preferably 30% by weight or less, still more preferably 20% by weight or less. When the content is 40% by weight or less, components having a low molecular weight tend to be difficult to remain.

At the end of the dropping, the content of the high molecular weight (for example, 100,000 or more, preferably 500,000 or more) component is not particularly limited, but is 40% by weight with respect to the total weight (100% by weight) of the monomer. The following is preferable, more preferably 30% by weight or less, still more preferably 20% by weight or less. When the content is 40% by weight or less, a component having a high molecular weight tends to be difficult to remain.

In the above drop polymerization method, as _{a specific method for producing the photoresist resin of the present invention in which Mw tA} <Mw _tB , the production methods described in the following (i) to (iii) are preferable. Further, in the above-mentioned dropping polymerization method, any one of the following (i) to (iii) may be adopted, or two or more may be adopted in combination.
(I) A method for producing a resin for a photoresist obtained by radically polymerizing the monomer by a dropping polymerization method in which the monomer and the polymerization initiator are dropped, and 10 minutes or more after the start of dropping the polymerization initiator. It elapsed the monomer starts dropping in after, the concentration of the polymerization initiator in the reaction solution at an arbitrary time t _C between after start of the dropping of the monomer until the completion of the dropwise addition and (I _tC) , the relationship between the concentration of the polymerization initiator in the reaction solution (I _tD) at any time t _D between until the completion of the dropwise addition after the t _C is, the photoresist resin is I _tC> I _tD Production method;
(Ii) A method for producing a resin for a photoresist obtained by radical polymerization of the above-mentioned monomer in the presence of a chain transfer agent by a dropping-polymerization method in which the monomer and the polymerization initiator are added dropwise. _{The concentration (C tE} ) of the chain transfer agent in the reaction solution at _{an arbitrary time t E} until the end of the dropping and the _{reaction solution at an arbitrary time t F} between the end of the _{t E} and the end of the dropping. A method for producing a resin for a photoresist in which the relationship with the concentration of the chain transfer agent (C _{tF ) is C tE} > C _tF;
(Iii) A method for producing a resin for a photoresist obtained by radical polymerization of the monomer by a dropping polymerization method in which a monomer and a polymerization initiator are dropped, and the total amount of dropping of the monomer is dropped. When the content is less than 15% by weight based on the monomer, the reaction temperature is lowered, and the temperature at the start of dropping the monomer and the polymerization initiator (T ₀ ) and the temperature at the end of dropping (T ₁ ) are shown. The relationship is T ₀ > T _{1 , and the temperature (T tG} ) of the reaction solution at _{an arbitrary time t G} from the start of the dropping to the end of the dropping and the temperature from after the above t _G to the end of the dropping A method for producing a resin for a photoresist in which the relationship with the _{temperature (T tH} ) of the reaction solution at an arbitrary time t _{H is T tG} ≥ T _tH.

In the above (i), the above t _C is an arbitrary time from the start of dropping the monomer and the polymerization initiator to the end of dropping. The t _D is an arbitrary time from the start of the dropping to the end of the dropping. The above-mentioned t _C and the above-mentioned t _D have a relationship of "t _C <t _D". In the above (i), “after the start of dropping” and “at the end of dropping” _{in the above t C} and the above t _{D are after the start of dropping and the end of dropping of the monomer.}

In the above (i), the concentration of the polymerization initiator in the reaction solution at the time t _C (I _tC), the relationship between the concentration of the polymerization initiator in the reaction solution (I _tD) in the time t _D, I _tC > _ItD . That is, from the start of dropping the monomer to the end of dropping, the polymerization initiator is consumed for the polymerization reaction, and _{the relationship of "ItC} > _ItD " is always established in the reaction solution, and the polymerization reaction As the polymerization reaction progresses from the initial stage to the final stage, the concentration of the polymerization initiator decreases. The concentration of the polymerization initiator does not include structural units derived from the polymerization initiator used in the polymerization reaction of the monomer and incorporated into the produced polymer.

In the above (i), the dropping of the monomer is started 10 minutes or more after the start of dropping the polymerization initiator. That is, in the above (i), the dropping of the polymerization initiator is started first, and then the dropping of the monomer is started after 10 minutes or more have passed. The dropping of the monomer is preferably started 30 minutes or more after the start of dropping the polymerization initiator, and more preferably 1 hour or more. As a result, since a large amount of polymerization initiator is present in the reaction vessel at the start of dropping the monomer, it becomes difficult to produce a polymer having a large weight average molecular weight at the initial stage of the polymerization reaction. Further, as compared with the case where the polymerization initiator to be dropped is placed in the reaction vessel in advance, even when the amount of the polymerization initiator to be dropped is increased and the scale is increased, the activity is activated at the start of dropping the monomer. Since the converted polymerization initiator is sufficiently present in the reaction vessel, it becomes difficult to produce a polymer having a large weight average molecular weight at the initial stage of the polymerization reaction. The start of dropping of the end monomer is not particularly limited, but is preferably within 24 hours, more preferably within 12 hours after the start of dropping of the polymerization initiator.

In (i) above, the _ItC is not particularly limited as long as it is lower than the concentration of the polymerization initiator in the reaction vessel before the start of dropping the monomer (initial concentration of the polymerization initiator). Further, the It _D is not particularly limited as long as it is lower than the It _C.

In the above (i), the initial concentration of the polymerization initiator is not particularly limited, but is preferably 0.1 to 5.0% by weight, more preferably 0.% by weight, based on the weight of the reaction solution (100% by weight). It is 2 to 3.0% by weight.

In the above (i), the concentration of the polymerization initiator in the reaction solution at the end of dropping is not particularly limited, but is preferably 0.05 to 4.0% by weight with respect to the weight (100% by weight) of the reaction solution. , More preferably 0.1 to 2.0% by weight.

In the above (i), from the viewpoint of preventing the concentration of the polymerization initiator in the reaction solution from increasing when the polymerization initiator is added dropwise, the concentration of the polymerization initiator to be dropped is the polymerization in the reaction solution immediately before the addition. It is preferably lower than the concentration of the initiator. When the polymerization initiator to be dropped is a solution, the concentration of the polymerization initiator in the solution is not particularly limited, but is 0.1 to 5.0% by weight based on the weight (100% by weight) of the solution. It is preferably, more preferably 0.2 to 3.0% by weight.

The dropping polymerization in (ii) above is a dropping polymerization method in which a monomer is radically polymerized in the presence of a chain transfer agent. In (ii) above, the chain transfer agent may be present in the reaction vessel before the start of dropping, or may be dropped together with the monomer and / or the polymerization initiator to be dropped, or both. There may be.

In the above (ii), the above t _E is an arbitrary time from the start of dropping the monomer and the polymerization initiator to the end of dropping. The t _F is an arbitrary time from the start of the dropping to the end of the dropping. The above-mentioned t _E and the above-mentioned t _F have a relationship of "t _E <t _F". In (ii) above, _{"after the start of dropping" and "at the end of dropping" in the above t E} and t _F are the same as "after the start of dropping" and "at the end of dropping" in the above t _A and the above t _B. Is.

In (ii) above, the relationship between the concentration of the chain transfer agent in the reaction solution at _{time t E (C tE} ) and the concentration of the chain transfer agent in the reaction solution at _{time t F (C tF) is C. tE} > C _tF . That is, from the start of dropping to the end of dropping, the chain transfer agent is consumed for the polymerization reaction, and _{the relationship of "C tE} > C _tF " always holds in the reaction solution, from the beginning to the end of the polymerization reaction. As the polymerization reaction progresses, the concentration of the chain transfer agent decreases. The concentration of the chain transfer agent does not include structural units derived from the chain transfer agent used in the polymerization reaction of the monomer and incorporated into the produced polymer.

In (ii) above, the C _tE is not particularly limited as long as it is lower than the concentration of the chain transfer agent (initial concentration of the chain transfer agent) in the reaction vessel before the start of dropping of the monomer and the polymerization initiator. Further, the C _tF is not particularly limited as long as it is lower than the _{C tE.}

In the above (ii), when the chain transfer agent is present in the reaction vessel before the start of dropping, the concentration of the chain transfer agent (initial concentration of the chain transfer agent) in the reaction vessel before the start of dropping is not particularly limited. However, it is preferably 0.1 to 5.0% by weight, more preferably 0.2 to 3.0% by weight, based on the weight of the reaction solution (100% by weight).

In (ii) above, the concentration of the chain transfer agent in the reaction solution at the end of dropping is not particularly limited, but is preferably 0.1 to 4.0% by weight with respect to the weight (100% by weight) of the reaction solution. , More preferably 0.1 to 2.0% by weight.

In (ii) above, when the chain transfer agent is added dropwise together with the monomer and the polymerization initiator, the viewpoint of preventing the concentration of the chain transfer agent in the reaction solution from increasing when the chain transfer agent is added dropwise. Therefore, the concentration of the chain transfer agent in the liquid is preferably lower than the concentration of the chain transfer agent in the reaction solution immediately before dropping. When a solution containing a chain transfer agent is added dropwise, the concentration of the chain transfer agent in the solution is not particularly limited, but is 0.1 to 5.0% by weight based on the weight (100% by weight) of the solution. Is preferable, and more preferably 0.2 to 3.0% by weight.

In (iii) above, t _G is an arbitrary time between the start of dropping the monomer and the polymerization initiator and the end of dropping. The t _H is an arbitrary time from the start of the dropping to the end of the dropping. The above-mentioned t _G and the above-mentioned t _H have a relationship of “t _G <t _H”. In (iii) above, _{"after the start of dropping" and "at the end of dropping" in the above t G} and t _H are the same as "after the start of dropping" and "at the end of dropping" in the above t _A and the above t _B. Is.

In the dropping polymerization in (iii) above, the relationship between _{the temperature (T 0} ) at the start of dropping of the monomer and the polymerization initiator and _{the temperature (T 1} ) at the end of dropping _{is T 0} > T ₁ . That is, it has a step of lowering the temperature between the start of dropping and the end of dropping.

In (iii) above, the relationship between the temperature of the reaction solution at _{t G (T tG} ) and the temperature of the reaction solution at _{t H (T tH ) is T tG} ≥ T _tH , and T _tG > T _tH. Is preferable. That is, it is preferable to continuously (gradually) lower the temperature of the reaction solution from the start of dropping to the end of dropping.

T ₀ is the temperature of the reaction solution at the start of dropping (that is, at the start of dropping of the monomer and the polymerization initiator). When _{the dropping of the monomer and the polymerization initiator is started at the same time, T 0} is the temperature at the start of dropping of the monomer and the polymerization initiator, and the dropping of each of the monomer and the polymerization initiator is started. If the time to be dropped is different, it is the temperature at the start of dropping of the one that started dropping later.

T ₁ is the temperature of the reaction solution at the end of the dropping (that is, at the end of dropping the monomer and the polymerization initiator). Note that T ₁ is the temperature at the end of dropping of the monomer and the polymerization initiator when the dropping of the monomer and the polymerization initiator is completed at the same time, and the dropping of each of the monomer and the polymerization initiator is completed. If the time to polymerize is different, it is the temperature at the end of dropping the liquid that has been dropped later.

The T ₀ is, for example, about 30 to 150 ° C. (preferably about 60 to 120 ° C.). When T ₀ is 150 ° C. or lower, a decrease in molecular weight is suppressed, and the stability of the monomer and the produced polymer is improved, which is preferable. When T ₀ is 30 ° C. or higher, it is possible to further suppress the molecular weight from becoming too large, which is preferable.

The temperature difference between T ₀ and T _{1 (T 0} −T ₁ ) is not particularly limited, but is preferably 5 to 50 ° C, more preferably 5 to 30 ° C, and even more preferably 10 to 25 ° C. The T ₁ is, for example, about 25 to 120 ° C. (preferably about 60 to 80 ° C.). When the temperature difference is 50 ° C. or less, a polymer having an excessively large molecular weight tends to be difficult to form, which is preferable. On the other hand, when the temperature difference is 5 ° C. or higher, polymers and oligomers having a small molecular weight tend to be difficult to form, which is preferable.

In the above (iii), the temperature lowering start time is after the start of the dropping and when the dropping amount of the monomer is less than 15% by weight with respect to the total monomer to be dropped (that is, all the monomers to be dropped). (Before the dropping of the amount of 15% by weight is completed), preferably less than 10% by weight. The temperature may be lowered immediately after the start of the dropping. If the temperature lowering start time is before the end of 15% by weight dropping, it becomes easier to suppress the formation of a polymer having an excessively large molecular weight, and the polymerization reaction proceeds by the time the temperature lowering is completed to produce a polymer or oligomer having a small molecular weight. This is preferable because it makes it easier to suppress the above.

The temperature lowering rate from T ₀ to T ₁ is preferably about -1 ° C./1 minute to -1 ° C./60 minutes (preferably -1 ° C./3 minutes to -1 ° C./30 minutes). When the temperature lowering rate is -1 ° C./1 minute or slower, it tends to be easy to suppress the formation of polymers and oligomers having a small molecular weight, which is preferable. When the temperature lowering rate is -1 ° C./60 minutes or faster, it tends to be difficult to form a polymer having an excessively large molecular weight, which is preferable.

The _{temperature decrease from T 0} to T ₁ may be performed at a constant rate from the temperature decrease start time to the temperature decrease end time, or the temperature decrease rate may be changed at one or more times. For example, any time between the cooling start time to cooling end time When t _I, may change the cooling rate in the t _I. When the number of times the temperature lowering rate is changed from the start of the dropping to the end of the dropping is one, the temperature lowering rate from the start of the dropping to the time t _I when the temperature lowering rate is _{changed is from the above t I.} It is preferable that the rate of temperature decrease is faster than the rate of temperature decrease until the end of temperature decrease. When the temperature lowering rate is changed a plurality of times, it is preferable that the initial temperature lowering rate is the fastest and the temperature lowering rate is gradually decreased.

After the temperature is lowered to T ₁ , it is preferable to further provide a step of aging while maintaining _{the above T 1.} By providing the aging step, the yield of the target photoresist resin can be remarkably improved. The aging time is, for example, about 1 to 10 hours, preferably about 1 to 5 hours.

It is desirable to control the reaction temperature [T ₀ and T ₁ ] so as to minimize the swing width, and within ± 5 ° C. (preferably within ± 3 ° C., more preferably ± 1 ° C.) with respect to the set temperature. Within) is preferable.

[Resin composition for photoresist]
The photoresist resin composition of the present invention contains at least the photoresist resin of the present invention and a radiation-sensitive acid generator.

As the radiation-sensitive acid generator, a conventional or known compound that efficiently generates an acid by exposure to radiation such as visible light, ultraviolet rays, far ultraviolet rays, electron beams, and X-rays can be used. It is a compound consisting of the generated acid. Examples of the mother nucleus include onium salt compounds such as iodonium salt, sulfonium salt (including tetrahydrothiophenium salt), phosphonium salt, diazonium salt, and pyridinium salt, sulfonimide compound, sulfone compound, sulfonic acid ester compound, and di. Examples thereof include a sulfonyldiazomethane compound, a disulfonylmethane compound, an oxime sulfonate compound, and a hydrazine sulfonate compound. Examples of the acid generated by the above exposure include alkyl or alkyl fluorinated sulfonic acid, alkyl or alkyl fluorinated carboxylic acid, alkyl or alkyl fluorinated sulfonylimide acid and the like. These can be used alone or in combination of two or more.

The amount of the radiation-sensitive acid generator to be used can be appropriately selected according to the strength of the acid generated by irradiation with radiation, the ratio of each repeating unit in the photoresist resin, and the like. For example, 100 weight of the photoresist resin of the present invention. It can be selected from the range of 0.1 to 30 parts by weight, preferably 1 to 25 parts by weight, and more preferably 2 to 20 parts by weight.

The photoresist resin composition can be prepared, for example, by mixing the photoresist resin and a radiation-sensitive acid generator in a resist solvent. As the resist solvent, a glycol-based solvent, an ester-based solvent, a ketone-based solvent, a mixed solvent thereof and the like exemplified as the polymerization solvent can be used.

The concentration of the photoresist resin of the present invention in the photoresist resin composition is, for example, about 3 to 40% by weight. The resin composition for a photoresist may contain an alkali-soluble component such as an alkali-soluble resin (for example, a novolak resin, a phenol resin, an imide resin, or a carboxy group-containing resin), a colorant (for example, a dye), or the like.

The photoresist resin composition thus obtained is applied onto a substrate or a substrate, dried, and then exposed to a coating film (resist film) via a predetermined mask (or further baked after exposure). By forming a latent image pattern and then dissolving it in alkali, a fine pattern can be formed with high accuracy.

Examples of the base material or substrate include silicon wafers, metals, plastics, glass, ceramics and the like. The resin composition for photoresist can be applied by using a conventional application means such as a spin coater, a dip coater, and a roller coater. The thickness of the coating film is, for example, 0.05 to 20 μm, preferably about 0.1 to 2 μm.

Radiation such as visible light, ultraviolet rays, far ultraviolet rays, electron beams, and X-rays can be used for exposure.

A carboxy group of a polymerization unit (repeating unit having an acid-decomposable group), etc., in which an acid is generated from a radiation-sensitive acid generator by exposure and becomes alkaline-soluble by the action of the acid in the resin composition for photoresist. The protective group (acid-degradable group) is rapidly desorbed to generate a carboxy group or the like that contributes to solubilization. Therefore, a predetermined pattern can be formed with high accuracy by developing with an alkaline developer.

Hereinafter, the present invention will be described in more detail based on Examples, but the present invention is not limited to these Examples. The weight average molecular weight (Mw) and the number average molecular weight (Mn) of the resin were determined by GPC measurement (gel permeation chromatography) using a tetrahydrofuran solvent. Polystyrene was used as a standard sample, and a refractive index meter (Refractive Index Detector; RI detector) was used as a detector. For GPC measurement, a column manufactured by Showa Denko KK (trade name "KF-806L") connected in series was used, and the column temperature was 40 ° C, the RI temperature was 40 ° C, and the tetrahydrofuran flow velocity was 0.8 mL. It was done under the condition of / minute. The molecular weight distribution (Mw / Mn) was calculated from the above measured values. In addition, Example 2 is described as a reference example.

Example 1
In a round-bottom flask equipped with a reflux tube, a stirrer, and a three-way cock, 88.84 g of cyclohexanone was placed under a nitrogen atmosphere to maintain the temperature at 80 ° C., and while stirring, dimethyl-2,2'-azobisisobuty was added. Rate [Manufactured by Wako Pure Chemical Industries, Ltd., trade name "V-601"] A mixture of 2.04 g and 47.16 g of cyclohexanone (a solution containing a polymerization initiator) was added dropwise at a constant rate over 2 hours. .. After completion of the dropping, 1-cyano-5-methacryloyloxy-3-oxatricyclo [4.2.1.0 ^4,8 ] nonane-2-one 58.83 g (0.238 mol), 1-hydroxy- 3-methacryloyloxyadamantane 11.24 g (0.048 mol), 1- (1-methacryloyloxy-1-methylethyl) adamantane 49.92 g (0.191 mol), dimethyl-2,2'-azobisisobutyrate [ Wako Pure Chemical Industries, Ltd., trade name "V-601"] 6.12 g, cyclohexanone 544.00 g mixed solution (solution containing monomer and polymerization initiator) at a constant rate over 6 hours Dropped. After the start of dropping the above solution, sampling was performed from the reaction vessel at a predetermined time, and the sampled reaction solution was analyzed to confirm the concentration of the polymerization initiator in the reaction vessel and the molecular weight of the produced polymer (Table 1). After completion of dropping the above solution, stirring of the reaction solution was continued for another 2 hours.
After completion of the polymerization reaction, the mixture was added dropwise to a mixture (25 ° C.) of heptane and ethyl acetate 8: 2 (weight ratio) in an amount 10 times that of the reaction solution with stirring. The resulting precipitate was filtered off and dried under reduced pressure to obtain 105.8 g of the desired resin. When the recovered polymer was analyzed by GPC, Mw (weight average molecular weight) was 7200 and the molecular weight distribution (Mw / Mn) was 1.78.

Example 2
In a round-bottom flask equipped with a reflux tube, a stirrer, and a three-way cock, 136.00 g of cyclohexanone and 1.41 g of methyl thioglycolate (chain transfer agent) were placed in a nitrogen atmosphere, and the temperature was maintained at 80 ° C. and stirred. While 1-cyano-5-methacryloyloxy-3-oxatricyclo [4.2.1.0 ^4,8 ] nonane-2-one 58.83 g (0.238 mol), 1-hydroxy-3-methacryloyloxyadamantane 11.24 g (0.048 mol), 1- (1-methacryloyloxy-1-methylethyl) adamantane 49.92 g (0.191 mol), dimethyl-2,2'-azobisisobutyrate [Wako Pure Chemical Industries (Wako Pure Chemical Industries, Ltd.) A solution (a solution containing a monomer and a polymerization initiator) containing 3.05 g and 544.00 g of cyclohexanone manufactured by Co., Ltd., trade name "V-601"] was added dropwise at a constant rate over 6 hours. After the start of dropping the above solution, sampling is performed from the reaction vessel at a predetermined time, and the sampled reaction solution is analyzed to confirm the concentration of the polymerization initiator, the concentration of the chain transfer agent, and the molecular weight of the produced polymer in the reaction vessel. (Table 1). After completion of the dropping, stirring of the reaction solution was continued for another 2 hours.
After completion of the polymerization reaction, the mixture was added dropwise to a mixture (25 ° C.) of heptane and ethyl acetate 8: 2 (weight ratio) in an amount 10 times that of the reaction solution with stirring. The resulting precipitate was filtered off and dried under reduced pressure to obtain 97.5 g of the desired resin. When the recovered polymer was analyzed by GPC, Mw (weight average molecular weight) was 7100 and the molecular weight distribution (Mw / Mn) was 1.76.

Example 3
In a round-bottom flask equipped with a reflux tube, a stirrer, and a three-way cock, 136.00 g of cyclohexanone was placed in a nitrogen atmosphere, the temperature was maintained at 96 ° C., and 1-cyano-5-methacryloyloxy-3-3 was stirred. Oxatricyclo [4.2.1.0 ^4,8 ] nonane-2-one 58.83 g (0.238 mol), 1-hydroxy-3-methacryloyloxyadamantane 11.24 g (0.048 mol), 1-( 1-methacryloyloxy-1-methylethyl) adamantane 49.92 g (0.191 mol), dimethyl-2,2'-azobisisobutyrate [manufactured by Wako Pure Chemical Industries, Ltd., trade name "V-601"] A solution (a solution containing a monomer and a polymerization initiator) in which 3.05 g and 544.00 g of cyclohexanone were mixed was added dropwise at a constant rate over 6 hours. The temperature inside the flask was lowered at a temperature lowering rate of 4 ° C./h until 4 hours after the start of dropping the above solution and 2.5 ° C./h after 4 hours until the completion of dropping the monomer solution. As a result of this temperature lowering operation, the temperature inside the flask at the end of dropping the solution was 75 ° C. After the start of dropping the above solution, sampling was performed from the reaction vessel at a predetermined time, and the sampled reaction solution was analyzed to confirm the concentration of the polymerization initiator in the reaction vessel and the molecular weight of the produced polymer (Table 1). After completion of the dropping, stirring of the reaction solution was continued for another 2 hours.
After completion of the polymerization reaction, the mixture was added dropwise to a mixture (25 ° C.) of heptane and ethyl acetate 8: 2 (weight ratio) in an amount 10 times that of the reaction solution with stirring. The resulting precipitate was separated by filtration and dried under reduced pressure to obtain 99.7 g of a desired resin. When the recovered polymer was analyzed by GPC, Mw (weight average molecular weight) was 7300 and the molecular weight distribution (Mw / Mn) was 1.78.

Example 4
In a round-bottom flask equipped with a reflux tube, a stirrer, and a three-way cock, 43.81 g of propylene glycol monomethyl ether acetate and 29.21 g of propylene glycol monomethyl ether were placed in a nitrogen atmosphere, and the temperature was kept at 80 ° C. while stirring. , Dimethyl-2,2'-azobisisobutyrate [manufactured by Wako Pure Chemical Industries, Ltd., trade name "V-601"] 1.09 g, propylene glycol monomethyl ether acetate 28.19 g, propylene glycol monomethyl ether 18. A mixed solution of 79 g (a solution containing a polymerization initiator) was added dropwise at a constant rate over 1 hour. After the completion of the dropping, the methacrylic acid-5-oxo-4-oxatricyclo [4.2.1.0 ^3,7 ] nonane-2-yl 51.98 g (0.234 mol), methacrylic acid-3,5 -Dihydroxyadamantan-1-yl 14.75 g (0.059 mol), methacrylic acid-1-ethylcyclopentane-1-yl 53.27 g (0.293 mol), dimethyl-2,2'-azobisisobutyrate [ Wako Pure Chemical Industries, Ltd., trade name "V-601"] 6.59 g, propylene glycol monomethyl ether acetate 216.00 g, propylene glycol monomethyl ether 144.00 g mixed solution (monomer and polymerization initiator The contained solution) was added dropwise at a constant rate over 6 hours. After the start of dropping the above solution, sampling was performed from the reaction vessel at a predetermined time, and the sampled reaction solution was analyzed to confirm the concentration of the polymerization initiator in the reaction vessel and the molecular weight of the produced polymer (Table 1). After completion of dropping the above solution, stirring of the reaction solution was continued for another 2 hours.
After completion of the polymerization reaction, the reaction solution is diluted with 200.00 g of propylene glycol monomethyl ether acetate, and after dilution, a mixture of 7.5 times the amount of heptane and ethyl acetate (weight ratio) of 7.5 times the reaction solution (25 ° C.) ), The reaction solution was added dropwise after the dilution with stirring. The resulting precipitate was separated by filtration and dried under reduced pressure to obtain 112.2 g of the desired resin. When the recovered polymer was analyzed by GPC, Mw (weight average molecular weight) was 7200 and the molecular weight distribution (Mw / Mn) was 1.85.

Example 5
In a round bottom flask equipped with a reflux tube, a stirrer and a three-way cock, 43.81 g of propylene glycol monomethyl ether acetate and 29.21 g of propylene glycol monomethyl ether acetate were placed in a nitrogen atmosphere, and the temperature was maintained at 96 ° C. while stirring. , Methacrylic acid-5-oxo-4-oxatricyclo [4.2.1.0 ^3,7 ] Nonan-2-yl 51.98 g (0.234 mol), Methacrylic acid-3,5-dihydroxyadamantan-1 -Il 14.75 g (0.059 mol), methacrylic acid-1-ethylcyclopentane-1-yl 53.27 g (0.293 mol), dimethyl-2,2'-azobisisobutyrate [Wako Pure Chemical Industries (Wako Pure Chemical Industries, Ltd.) A solution (a solution containing a monomer and a polymerization initiator) in which 8.88 g, 244.19 g of propylene glycol monomethyl ether acetate and 162.79 g of propylene glycol monomethyl ether are mixed, manufactured by Co., Ltd., trade name "V-601"]. It was added dropwise at a constant rate over 6 hours. The temperature inside the flask was lowered at a temperature lowering rate of 4 ° C./h until 4 hours after the start of dropping the above solution and 2.5 ° C./h after 4 hours until the completion of dropping the monomer solution. As a result of this temperature lowering operation, the temperature inside the flask at the end of dropping the solution was 75 ° C. After the start of dropping the above solution, sampling was performed from the reaction vessel at a predetermined time, and the sampled reaction solution was analyzed to confirm the concentration of the polymerization initiator in the reaction vessel and the molecular weight of the produced polymer (Table 1). After completion of the dropping, stirring of the reaction solution was continued for another 2 hours.
After completion of the polymerization reaction, the reaction solution is diluted with 200.00 g of propylene glycol monomethyl ether acetate, and after dilution, a mixture of 7.5 times the amount of heptane and ethyl acetate (weight ratio) of 7.5 times the reaction solution (25 ° C.) ), The reaction solution was added dropwise after the dilution with stirring. The resulting precipitate was filtered off and dried under reduced pressure to obtain 109.4 g of the desired resin. When the recovered polymer was analyzed by GPC, Mw (weight average molecular weight) was 7100 and the molecular weight distribution (Mw / Mn) was 1.78.

Example 6
In a round-bottom flask equipped with a reflux tube, a stirrer, and a three-way cock, 209.60 g of propylene glycol monomethyl ether acetate and 314.40 g of methyl ethyl ketone were placed in a nitrogen atmosphere, and the temperature was maintained at 80 ° C. 2,2'-azobisisobutyrate [manufactured by Wako Pure Chemical Industries, Ltd., trade name "V-601"] 6.68 g, methyl thioglycolate (chain transfer agent) 3.08 g, propylene glycol monomethyl ether acetate A solution (a solution containing a polymerization initiator and a chain transfer agent) in which 57.60 g and 86.40 g of methyl ethyl ketone were mixed was added dropwise at a constant rate over 8 hours. Two hours after the start of dropping the solution, -2-(6-cyano-5-oxo-4-oxatricyclo [4.2.1.0 ^3,7 ] nonane-2-) methacrylic acid Iloxy) -2-oxoethyl 249.49 g (0.818 mol), methacrylic acid-1- (adamantane-1-yl) -1-methylpropyl 150.51 g (0.545 mol), propylene glycol monomethyl ether acetate 372.80 g, A solution containing 559.20 g of methyl ethyl ketone (a solution containing a monomer) was added dropwise at a constant rate over 6 hours. After the start of dropping the above solution, sampling was performed from the reaction vessel at a predetermined time, and the sampled reaction solution was analyzed to confirm the concentration of the polymerization initiator in the reaction vessel and the molecular weight of the produced polymer (Table 1). After completion of dropping the above solution, stirring of the reaction solution was continued for another 2 hours.
After completion of the polymerization reaction, the reaction solution is diluted with 666.67 g of propylene glycol monomethyl ether acetate, and after dilution, a mixture of 7.5 times the amount of heptane and ethyl acetate (weight ratio) of 7.5 times the reaction solution (25 ° C.) ), The reaction solution was added dropwise after the dilution with stirring. The resulting precipitate was filtered off and dried under reduced pressure to obtain 342.0 g of the desired resin. When the recovered polymer was analyzed by GPC, Mw (weight average molecular weight) was 10400 and the molecular weight distribution (Mw / Mn) was 1.89.

Example 7
In a round-bottom flask equipped with a reflux tube, a stirrer and a three-way cock, 209.60 g of propylene glycol monomethyl ether acetate and 314.40 g of methyl ethyl ketone were placed in a nitrogen atmosphere, and the temperature was maintained at 80 ° C. 2,2'-Azobisisobutyrate [manufactured by Wako Pure Chemical Industries, Ltd., trade name "V-601"] 19.20 g, propylene glycol monomethyl ether acetate 57.60 g, methyl ethyl ketone 86.40 g mixed solution ( The solution containing the polymerization initiator) was added dropwise at a constant rate over 7 hours. One hour after the start of dropping the solution, -2- methacrylic acid (6-cyano-5-oxo-4-oxatricyclo [4.2.1.0 ^3,7 ] nonane-2- Iloxy) -2-oxoethyl 249.49 g (0.818 mol), methacrylic acid-1- (adamantane-1-yl) -1-methylpropyl 150.51 g (0.545 mol), propylene glycol monomethyl ether acetate 372.80 g, A solution containing 559.20 g of methyl ethyl ketone (a solution containing a monomer) was added dropwise at a constant rate over 6 hours. After the start of dropping the above solution, sampling was performed from the reaction vessel at a predetermined time, and the sampled reaction solution was analyzed to confirm the concentration of the polymerization initiator in the reaction vessel and the molecular weight of the produced polymer (Table 1). After completion of dropping the above solution, stirring of the reaction solution was continued for another 2 hours.
After completion of the polymerization reaction, the reaction solution is diluted with 666.67 g of propylene glycol monomethyl ether acetate, and after dilution, a mixture of 7.5 times the amount of heptane and ethyl acetate (weight ratio) of 7.5 times the reaction solution (25 ° C.) ), The reaction solution was added dropwise after the dilution with stirring. The resulting precipitate was filtered off and dried under reduced pressure to obtain 353.3 g of the desired resin. When the recovered polymer was analyzed by GPC, Mw (weight average molecular weight) was 10500 and the molecular weight distribution (Mw / Mn) was 1.98.

Example 8
In a round-bottom flask equipped with a reflux tube, a stirrer, and a three-way cock, 322.70 g of propylene glycol monomethyl ether acetate and 215.13 g of methyl ethyl ketone were placed in a nitrogen atmosphere, and the temperature was maintained at 80 ° C. A mixed solution of 2,2'-azobisisobutyrate [manufactured by Wako Pure Chemical Industries, Ltd., trade name "V-601"] 38.00 g, propylene glycol monomethyl ether acetate 53.20 g, and methyl ethyl ketone 35.47 g ( The solution containing the polymerization initiator) was added dropwise at a constant rate over 6 hours. Two hours after the start of dropping the solution, methacrylic acid-5,5-dioxo-4-oxa-5-thiatricyclo [4.2.1.0 ^3,7 ] nonane-2-yl 195. 45 g (0.758 mol), -1- (cyclohexane-1-yl) -1-methylethyl 106.06 g (0.505 mol), -2-methyladamantan-2-yl methacrylate 98.48 g (0. 421 mol), a mixed solution of 584.10 g of propylene glycol monomethyl ether acetate and 389.40 g of methyl ethyl ketone (a solution containing a monomer) was added dropwise at a constant rate over 4 hours. After the start of dropping the above solution, sampling was performed from the reaction vessel at a predetermined time, and the sampled reaction solution was analyzed to confirm the concentration of the polymerization initiator in the reaction vessel and the molecular weight of the produced polymer (Table 1). After completion of dropping the above solution, stirring of the reaction solution was continued for another 2 hours.
After completion of the polymerization reaction, the reaction solution is diluted with 666.67 g of propylene glycol monomethyl ether acetate, and after dilution, a mixture of 7.5 times the amount of heptane and ethyl acetate (weight ratio) of 7.5 times the reaction solution (25 ° C.) ), The reaction solution was added dropwise after the dilution with stirring. The resulting precipitate was separated by filtration and dried under reduced pressure to obtain 300.4 g of a desired resin. When the recovered polymer was analyzed by GPC, Mw (weight average molecular weight) was 5200 and the molecular weight distribution (Mw / Mn) was 1.65.

Example 9
In a round bottom flask equipped with a reflux tube, a stirrer and a three-way cock, 534.80 g of propylene glycol monomethyl ether acetate was placed in a nitrogen atmosphere, the temperature was maintained at 80 ° C., and the mixture was stirred while dimethyl-2,2'-. 6 A mixture of 11.20 g of azobisisobutyrate [manufactured by Wako Pure Chemical Industries, Ltd., trade name "V-601"] and 100.80 g of propylene glycol monomethyl ether acetate (solution containing a polymerization initiator). It was added dropwise at a constant rate over time. When 2 hours have passed since the start of dropping the solution, 58.05 g (0.341 mol) of -2-oxotetraxhexyl methacrylate-3-yl methacrylate and -2- (6-cyano-5-oxo-4) methacrylic acid -Oxatricyclo [4.2.1.0 ^3,7 ] nonane-2-yloxy) -2-oxoethyl 156.21 g (0.512 mol), methacrylic acid-1- (cyclohexane-1-yl) -1- A solution (containing monomer) in which 143.41 g (0.683 mol) of methyl ethyl, 43.24 g (0.171 mol) of -2-ethyladamantan-2-yl methacrylate, and 964.40 g of propylene glycol monomethyl ether acetate are mixed. The solution) was added dropwise at a constant rate over 4 hours. After the start of dropping the above solution, sampling was performed from the reaction vessel at a predetermined time, and the sampled reaction solution was analyzed to confirm the concentration of the polymerization initiator in the reaction vessel and the molecular weight of the produced polymer (Table 1). After completion of dropping the above solution, stirring of the reaction solution was continued for another 2 hours.
After completion of the polymerization reaction, the reaction solution is diluted with 666.67 g of propylene glycol monomethyl ether acetate, and after dilution, a mixture of 7.5 times the amount of heptane and ethyl acetate (weight ratio) of 7.5 times the reaction solution (25 ° C.) ), The reaction solution was added dropwise after the dilution with stirring. The resulting precipitate was separated by filtration and dried under reduced pressure to obtain 330.0 g of a desired resin. When the recovered polymer was analyzed by GPC, Mw (weight average molecular weight) was 12600 and the molecular weight distribution (Mw / Mn) was 2.10.

Comparative Example 1
In a round-bottom flask equipped with a reflux tube, a stirrer and a three-way cock, add 136.00 g of cyclohexanone under a nitrogen atmosphere, keep the temperature at 80 ° C., and stir while stirring 1-cyano-5-methacryloyloxy-3-3. Oxatricyclo [4.2.1.0 ^4,8 ] nonane-2-one 58.83 g (0.238 mol), 1-hydroxy-3-methacryloyloxyadamantane 11.24 g (0.048 mol), 1-( 1-methacryloyloxy-1-methylethyl) adamantane 49.92 g (0.191 mol), dimethyl-2,2'-azobisisobutyrate [manufactured by Wako Pure Chemical Industries, Ltd., trade name "V-601"] A solution (a solution containing a monomer and a polymerization initiator) in which 8.16 g and 544.00 g of cyclohexanone were mixed was added dropwise at a constant rate over 6 hours. After the start of dropping the above solution, sampling was performed from the reaction vessel at a predetermined time, and the sampled reaction solution was analyzed to confirm the concentration of the polymerization initiator in the reaction vessel and the molecular weight of the produced polymer (Table 1). After completion of dropping the monomer solution, stirring of the reaction solution was continued for another 2 hours.
After completion of the polymerization reaction, the mixture was added dropwise to a mixture (25 ° C.) of heptane and ethyl acetate 8: 2 (weight ratio) in an amount 10 times that of the reaction solution with stirring. The resulting precipitate was separated by filtration and dried under reduced pressure to obtain 97.7 g of a desired resin. When the recovered polymer was analyzed by GPC, Mw (weight average molecular weight) was 7100 and the molecular weight distribution (Mw / Mn) was 1.82.

Comparative Example 2
In a round bottom flask equipped with a reflux tube, a stirrer, and a three-way cock, 72.00 g of propylene glycol monomethyl ether acetate and 48.00 g of propylene glycol monomethyl ether were placed in a nitrogen atmosphere, and the temperature was kept at 80 ° C. while stirring. , Methacrylic acid-5-oxo-4-oxatricyclo [4.2.1.0 ^3,7 ] Nonan-2-yl 51.98 g (0.234 mol), Methacrylic acid-3,5-dihydroxyadamantan-1 -Il 14.75 g (0.059 mol), methacrylic acid-1-ethylcyclopentane-1-yl 53.27 g (0.293 mol), dimethyl-2,2'-azobisisobutyrate [Wako Pure Chemical Industries (Wako Pure Chemical Industries, Ltd.) Co., Ltd., trade name "V-601"] 7.44 g, 216.00 g of propylene glycol monomethyl ether acetate, 144.00 g of propylene glycol monomethyl ether mixed solution (solution containing monomer and polymerization initiator). It was added dropwise at a constant rate over 6 hours. After the start of dropping the above solution, sampling was performed from the reaction vessel at a predetermined time, and the sampled reaction solution was analyzed to confirm the concentration of the polymerization initiator in the reaction vessel and the molecular weight of the produced polymer (Table 1). After completion of dropping the monomer solution, stirring of the reaction solution was continued for another 2 hours.
After completion of the polymerization reaction, the reaction solution is diluted with 200.00 g of propylene glycol monomethyl ether acetate, and after dilution, a mixture of 7.5 times the amount of heptane and ethyl acetate (weight ratio) of 7.5 times the reaction solution (25 ° C.) ), The reaction solution was added dropwise after the dilution with stirring. The resulting precipitate was filtered off and dried under reduced pressure to obtain 107.1 g of the desired resin. When the recovered polymer was analyzed by GPC, Mw (weight average molecular weight) was 7,000 and the molecular weight distribution (Mw / Mn) was 1.82.

Comparative Example 3
In a round bottom flask equipped with a reflux tube, a stirrer and a three-way cock, 224.00 g of propylene glycol monomethyl ether acetate and 336.00 g of methyl ethyl ketone were placed in a nitrogen atmosphere, and the temperature was maintained at 80 ° C. A mixed solution of 2,2'-azobisisobutyrate [manufactured by Wako Pure Chemical Industries, Ltd., trade name "V-601"] 18.40 g, propylene glycol monomethyl ether acetate 57.60 g, and methyl ethyl ketone 86.40 g ( Solution containing polymerization initiator) and -2-(6-cyano-5-oxo-4-oxatricyclo [4.2.1.0 ^3,7 ] nonane-2-yloxy) -2-methacrylic acid Oxoethyl 249.49 g (0.818 mol), methacrylic acid-1- (adamantan-1-yl) -1-methylpropyl 150.51 g (0.545 mol), propylene glycol monomethyl ether acetate 358.40 g, methyl ethyl ketone 537.60 g. The mixed solution (solution containing the monomer) was started to be added dropwise at the same time, and each of them was added dropwise at a constant rate over 6 hours. After the start of dropping the above solution, sampling was performed from the reaction vessel at a predetermined time, and the sampled reaction solution was analyzed to confirm the concentration of the polymerization initiator in the reaction vessel and the molecular weight of the produced polymer (Table 1). After completion of dropping the monomer solution, stirring of the reaction solution was continued for another 2 hours.
After completion of the polymerization reaction, the reaction solution is diluted with 666.67 g of propylene glycol monomethyl ether acetate, and after dilution, a mixture of 7.5 times the amount of heptane and ethyl acetate (weight ratio) of 7.5 times the reaction solution (25 ° C.) ), The reaction solution was added dropwise after the dilution with stirring. The resulting precipitate was filtered off and dried under reduced pressure to obtain 357.8 g of the desired resin. When the recovered polymer was analyzed by GPC, Mw (weight average molecular weight) was 10100 and the molecular weight distribution (Mw / Mn) was 2.02.

The resins produced in Examples 1 to 3 and Comparative Example 1 have a polymerization unit represented by the following formula.

The resins prepared in Examples 4, 5 and Comparative Example 2 have a polymerization unit represented by the following formula.

The resins prepared in Examples 6 and 7 and Comparative Example 3 have a polymerization unit represented by the following formula.

The resin produced in Example 8 has a polymerization unit represented by the following formula.

The resin produced in Example 9 has a polymerization unit represented by the following formula.

Example 10
To 2.0 g of each of the resins obtained in Examples 1 to 9 and Comparative Examples 1 to 3, 18.0 g of 1-methoxy-2-propyl acetate was added, and the mixture was stirred at 23 ° C. for 6 hours. After the stirring was completed, the presence or absence of dissolution was visually confirmed and evaluated according to the following criteria. The results are shown in the "Dissolution Test" column of Table 1.
○ (Good): The solution is transparent and no undissolved residue is seen.
× (Defective): Undissolved residue is seen, or the solution is cloudy.

Claims (5)

A method for producing a resin for a photoresist, which is obtained by radically polymerizing the monomer by a dropping polymerization method in which a monomer and a polymerization initiator are dropped.
After 10 minutes or more have passed from the start of dropping the polymerization initiator, the monomer is started to be dropped, and from the start of dropping the monomer to the end of dropping (the monomer and the polymerization initiator are dropped at the same time). When it ends, it is when the dropping of the monomer and the polymerization initiator ends, and when the dropping times of the monomer and the polymerization initiator are different, when the dropping of the component whose dropping ends later ends. ) and the concentration of the polymerization initiator in the reaction solution at an arbitrary time t _C during up (I _tC), wherein in the reaction solution at an arbitrary time t _D between after the t _C until completion of the dropwise addition The relationship with the polymerization initiator concentration ( _{ItD ) is always ItC} > _ItD .
The weight average molecular weight of the polymer produced at an arbitrary time t _A between the after start of the dropping of the monomer until the completion of the dropwise addition and (Mw _tA), any period from after the t _A until the completion of the dropwise addition relationship of the weight average molecular weight of the resulting polymer at the time t _B and (Mw _tB) of a Mw _tA <Mw _tB always, manufacturing method of a photoresist resin. A method for producing a resin for a photoresist, which is obtained by radical polymerization of the monomer in the presence of a chain transfer agent by a dropping polymerization method in which a monomer and a polymerization initiator are dropped.
Leave the presence of a polymerization initiator in a polymerization solvent before the start of the dropping of the previous SL monomer,
After the dropping of the monomer and the polymerization initiator is started (when the dropping of the monomer and the polymerization initiator is started at the same time, it is after the dropping of the monomer and the polymerization initiator is started, and the monomer And when the time to start dropping each of the polymerization initiators is different, after the start of dropping of the component which started dropping later) to the end of dropping (when the dropping of the monomer and the polymerization initiator ends at the same time, the above It is the time when the dropping of the monomer and the polymerization initiator is completed, and when the dropping times of the monomer and the polymerization initiator are different, the time until the dropping of the component whose dropping is completed later is completed). and the concentration of the chain transfer agent in the reaction solution at an arbitrary time t _E (C _tE), the chain transfer agent in the reaction solution at an arbitrary time t _F between after the t _E until the completion of the dropwise addition The relationship with the concentration (C _{tF ) is always C tE} > C _tF , and
The weight average molecular weight of the resulting polymer at an arbitrary time t _A between after the dropping start to the said completion of the dropwise addition and (Mw _tA), an arbitrary time t _B between after the t _A until the completion of the dropwise addition relationship between the weight average molecular weight of the produced polymer (Mw _tB) in is the Mw _tA <Mw _tB always, manufacturing method of a photoresist resin. A method for producing a resin for a photoresist, which is obtained by radically polymerizing the monomer by a dropping polymerization method in which a monomer and a polymerization initiator are dropped.
When the dropping amount of the monomer is less than 15% by weight based on the total dropping amount, the reaction temperature is lowered, and when the dropping of the monomer and the polymerization initiator is started (the monomer). When the dropping of the monomer and the polymerization initiator is started at the same time, it is after the dropping of the monomer and the polymerization initiator is started, and when the dropping times of the monomer and the polymerization initiator are different, it is later. The temperature (T ₀ ) at the temperature (T 0) at the start of dropping of the component that started dropping and the end of dropping of the monomer and the polymerization initiator when the dropping of the monomer and the polymerization initiator ends at the same time. When the time at which the dropping of the monomer and the polymerization initiator is completed is different , the relationship with the temperature (T _{1 ) of the component whose dropping is completed later is T 0} > T. _1, the temperature of the reaction solution (T _tG) at an arbitrary time t _G between after the dropping start to the said completion of the dropwise addition, any time t between after the t _G until the completion of the dropwise addition The relationship with the reaction solution temperature (T _{tH ) in H is always T tG} > T _tH .
The weight average molecular weight of the resulting polymer at an arbitrary time t _A between after the dropping start to the said completion of the dropwise addition and (Mw _tA), an arbitrary time t _B between after the t _A until the completion of the dropwise addition relationship between the weight average molecular weight of the produced polymer (Mw _tB) in is the Mw _tA <Mw _tB always, manufacturing method of a photoresist resin. A method for producing a photoresist resin composition, which comprises mixing the photoresist resin according to any one of claims 1 to 3 with a radiation-sensitive acid generator to produce a photoresist resin composition. A pattern forming method including at least a step of applying the photoresist resin composition according to claim 4 to a substrate to form a coating film, exposing the coating film, and then dissolving the alkali.