Upper-layer film forming composition and method for producing a phase-separated pattern

A composition, comprising:

• an upper-layer that is present directly on a layer comprising a block copolymer that is formed on a substrate, the upper layer including:
• (A) a random copolymer comprising (a) a unit structure derived from maleimide structure and a unit structure derived from styrene structure;
• and
• (B) an ether compound as a solvent, the ether compound represented by the following formula (6):
• A1-O-A2 Formula (6)
• wherein each of A1 and A2 independently represents a linear, branched, or cyclic saturated alkyl group having 1 to 15 carbon atoms and being optionally substituted, with the proviso that the ether compound has 8 to 16 carbon atoms;
• wherein
• the layer comprising the block copolymer has domains of the block copolymer that are oriented vertically;
• and the upper-layer is in the form of an upper-layer film, which is configured for causing phase separation and inducing reorientation of the block copolymer such that the domains of the block copolymer that are oriented vertically are present on the surface of the substrate without dissolving or swelling the layer comprising the block copolymer formed on the substrate, and
• the upper-layer film is soluble in a hydrophobic solvent and the block copolymer is insoluble in the hydrophobic solvent.