Block copolymer and method of producing the same, and method of producing structure containing phase-separated structure

1. A block copolymer comprising:

a first block consisting of a polymer having a repeating structure of a structural unit (u11) represented by general formula (u1-1) shown below; and

a second block consisting of a polymer having a repeating structure of a structural unit (u2) containing a silicon atom,

the second block containing a block (b21) consisting of a polymer having a repeating structure of a structural unit (u21) represented by general formula (u2-1-1) shown below, and a block (b22) consisting of a polymer having a repeating structure of a structural unit (221) derived from dimethylsiloxane, provided that the structural unit (u21) is excluded; and

the block (b22) is positioned between the first block and the block (b21),

wherein the block copolymer has a number average molecular weight of 13,400 to 21,800 and a polydispersity of 1.12 to 1.17,

the amount of the first block based on the total amount (100 mol %) of the first block, the block(b21) and the block (b22) is 40 to 70 mol %,

the amount of the block (b21) based on the total amount (100 mol %) of the first block, the block(b21) and the block (b22) is 15 to 35 mol %, and

the amount of the block (b22) based on the total amount (100 mol %) of the first block, the block(b21) and the block (b22) is 1 to 40 mol %,

wherein R P111 represents a hydrogen atom or a methyl group; and R P112 represents a phenyl group;

wherein R represents a methyl group or a hydrogen atom; R P213 represents a linear or alkylene group having 1 to 3 carbon atoms; and R P214 is a group represented by formula (R p214 -1-9) shown below:

wherein np1 represents 3 or 6.

2. The block copolymer according to claim 1 , wherein the amount of the block (b22) based on the total amount (100 mol %) of the first block, the block(b21) and the block (b22) is 15 to 40 mol %.

3. A method of producing a block copolymer according to claim 1 , the method comprising:

a step (a) of preparing a first block consisting of a polymer having a repeating structure of a structural unit (u11) represented by general formula (u1-1),

a step (b) of conducting addition polymerization of dimethylsiloxane with the first block prepared in the step (a), to prepare a block copolymer precursor in which the first block is bonded to a block (b22), and

a step (c) of conducting addition polymerization of a monomer (m21) which derives a structural unit (u21) represented by general formula (u2-1-1) with the block copolymer precursor prepared in the step (b), to prepare a block copolymer in which the block (b22) is positioned between the first block and a block (b21),

wherein, in the step (c), the reaction temperature of the addition polymerization of the monomer (m21) with the block copolymer precursor is adjusted to be lower than the reaction temperature of the addition polymerization of the siloxane dimethylsiloxane with the first block.

4. A method of producing a structure containing a phase-separated structure, the method comprising:

a step (i) in which a layer containing the block copolymer according to claim 1 is formed on a substrate, and

a step (ii) in which the layer containing the block copolymer is phase-separated.

5. The method according to claim 4 , which comprises, prior to step (i), forming a guide pattern on the substrate.