Method for producing polymer

1 . A method for producing a polymer, the method comprising:

a first step of reacting a monomer having the following formula (a) with a monomer having the following formula (b) in the presence of a quaternary phosphonium salt or a quaternary ammonium salt in an organic solvent to synthesize a crude polymer having a repeating unit having the following formula (1); and

a second step of mixing a solution containing the crude polymer obtained in the first step with a poor solvent to precipitate a purified polymer having the repeating unit having the formula (1), and filtering the polymer,

wherein As in the formula (1) and the formula (a) each independently represent a hydrogen atom, a methyl group, or an ethyl group, and Q 1 and Q 2 in the formula (1), the formula (a), and the formula (b) represent the formula (2) or the formula (3):

wherein Q 3 represents an alkylene group having 1 to 10 carbon atoms which may contain a sulfide bond or a disulfide bond, an alkenylene group having 2 to 10 carbon atoms, a phenylene group, a naphthylene group, or an anthrylene group; the phenylene group, the naphthylene group, and the anthrylene group may be each independently substituted with a substituent selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, a phenyl group, a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, a hydroxy group, and an alkylthio group having 1 to 6 carbon atoms; Bs each independently represent a single bond or an alkylene group having 1 to 5 carbon atoms; ns are each independently 0 or 1; ms are each independently 0 or 1; and X represents the formula (4), the formula (5), or the formula (6):

wherein R 1 s each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 3 to 6 carbon atoms, a benzyl group, or a phenyl group; the alkyl group and the alkenyl group may be substituted with a halogen atom, a hydroxy group, or a cyano group; in the benzyl group, a hydrogen atom on an aromatic ring may be substituted with a hydroxy group; the phenyl group may be substituted with a substituent selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, a hydroxy group, and an alkylthio group having 1 to 6 carbon atoms; two R's may be bonded to each other to form a ring having 3 to 6 carbon atoms; R 2 represents a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 3 to 6 carbon atoms, a benzyl group, or a phenyl group; and the phenyl group may be substituted with a substituent selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, a hydroxy group, and an alkylthio group having 1 to 6 carbon atoms; and

at least one of Q 1 and Q 2 contains a structure having the formula (3),

wherein the organic solvent used in the first step is one kind or two or more kinds selected from the group consisting of benzene, toluene, xylene, ethyl lactate, butyl lactate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, cyclohexanone, and N-methylpyrrolidone, and wherein the poor solvent used in the second step is one kind or two or more kinds selected from the group consisting of diethyl ether, cyclopentyl methyl ether, diisopropyl ether, and isopropyl alcohol, wherein the solution containing the crude polymer obtained in the first step is added to the poor solvent over 15 minutes to 1 hour per 50 g of the solution containing the crude polymer.

2 . A method for inhibiting generation of sublimate during film formation, the method comprising:

a first step of reacting any of monomers selected from the group of the following formulas (a) with a monomer having the following formula (b) in the presence of a quaternary phosphonium salt or a quaternary ammonium salt in an organic solvent to synthesize a crude polymer having a repeating unit having the following formula (1-1) or (1-3), and then, adding cation exchange resin and anion exchange resin to an obtained crude polymer solution to perform ion exchange treatment,

a second step of mixing a solution containing the crude polymer obtained in the first step with a poor solvent, then stirring for 10 minutes or more to precipitate a purified polymer having the repeating unit having the formula (1-1) or (1-3), and filtering the polymer; and

a step of applying the composition containing the purified polymer obtained in the second step onto a substrate and baking the composition to form a film,

wherein 54.6 wt % or more of a low molecular weight component having a weight average molecular weight of 1,000 or less is removed from the crude polymer by the second step,

3 . The method for inhibiting generation of sublimate during film formation according to claim 2 , wherein the organic solvent is propylene glycol monomethyl ether.

4 . The method for inhibiting generation of sublimate during film formation according to claim 2 , wherein the poor solvent is isopropyl alcohol.

5 . A method for producing a composition for forming resist underlayer film, comprising mixing a polymer obtained by the method according to claim 2 with an organic solvent.

6 . The method for inhibiting generation of sublimate during film formation according to claim 2 , wherein the organic solvent is propylene glycol monomethyl ether and the poor solvent is isopropyl alcohol.

7 . The method for inhibiting generation of sublimate during film formation according to claim 2 , wherein the solution containing the crude polymer obtained in the first step is added to the poor solvent over 15 minutes to 1 hour per 50 g of the solution containing the crude polymer.

8 . The method for inhibiting generation of sublimate during film formation according to claim 2 , wherein the total solid content of components is 5 to 40%, wherein the solid content means components in said first step other than solvents in said a solution.