Pattern forming method, actinic ray-sensitive or radiation-sensitive resin composition, resist film, manufacturing method of electronic device using the same, and electronic device
(1) a step of forming a film by using a sensitizing actinic ray or radiation-sensitive resin composition containing a resin (Ab) having a specific repeating unit, (2) a step of forming the film by using electron beams or extreme ultraviolet rays And (3) a step of developing the exposed film using an organic solvent-containing developer to form a negative pattern.