Self-assembly composition for pattern formation and pattern forming method

A self-assembly composition for pattern formation, which comprises a block copolymer comprising

• a polymerization unit (a) comprising two or more units consisting of at least one type selected from a glucose unit and a xylose unit, and
• a polymerization unit (b) comprising two or more units consisting of at least one type selected from an aromatic ring-containing unit, a silicon-containing unit and a metal-containing unit,
• wherein the polymerization unit (a) has a structure represented by the following formula (1) or the following formula (3):
• in Formula (1), each R1 independently represents a fluorine atom, a bromine atom, a chlorine atom, an iodine atom, an alkyl group, an acyl group, an aryl group or a phosphoryl group, and a plurality of R1 may be identical to or different from one another;
• and n represents an integer of 2 or more and 1500 or less,
• in Formula (3), each R1 independently represents a fluorine atom, a bromine atom, a chlorine atom, an iodine atom, an alkyl group, an acyl group, an aryl group or a phosphoryl group, and a plurality of R1 may be identical to or different from one another;
• R5 represents a hydrogen atom or an alkyl group, and a plurality of R5 may be identical to or different from one another;
• X and Y each independently represents a single bond or a linking group, wherein a plurality of X may be identical to or different from one another, and a plurality of Y may be identical to or different from one another;
• and p represents an integer of 2 or more and 1500 or less.