Pattern forming method, composition used therein, method for manufacturing electronic device, and electronic device

A pattern forming method, comprising:

• (i) a step of forming a first film by using an actinic ray-sensitive or radiation-sensitive resin composition (I) containing (A) a resin capable of increasing polarity by an action of an acid to decrease solubility in an organic solvent-containing developer, and (B) a compound capable of generating an acid upon irradiation with an actinic ray or radiation,
• (ii) a step of exposing the first film,
• (iii) a step of developing the exposed first film by using an organic solvent-containing developer to form a negative pattern,
• (iv) a step of forming a second film on the negative pattern by using a composition (II) containing (A′) a resin capable of increasing polarity by an action of an acid to decrease solubility in an organic solvent-containing remover,
• (v) a step of increasing polarity of the resin (A′) present in the second film by an action of an acid generated from the compound (B) present in the negative pattern formed in the step (iii), and
• (vi) a step of removing an area of the second film, in which the area is an area in which the resin (A′) has not yet undergone reaction with the acid generated from the compound (B), by using the organic solvent-containing remover,
• wherein:
• the organic solvent-containing developer in the step (iii) contains an organic solvent in an amount of from 90 mass % to 100 mass % based on the total amount of the developer;
• and
• the resin (A′) has a structure in which a polar group is protected with a group capable of leaving by the action of an acid, and the group capable of leaving by the action of an acid is —C(R36)(R37)(R38), wherein each of R36 to R38 independently represents an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group or an alkenyl group, and R36 and R37 may combine with each other to form a ring.