Pattern forming method, method for producing electronic device, and actinic ray-sensitive or radiation-sensitive resin composition for organic solvent development

A pattern forming method, comprising:

• forming a film using an actinic ray-sensitive or radiation-sensitive resin composition;
• irradiating the film with actinic rays or radiation;
• and
• developing the film irradiated with actinic rays or radiation using a developer containing an organic solvent,
• wherein the actinic ray-sensitive or radiation-sensitive resin composition contains a resin containing a repeating unit having an Si atom and a repeating unit having an acid-decomposable group and a compound capable of generating an acid upon irradiation with actinic rays or radiation,
• the content of Si atoms in the resin is 1.0 to 30 mass %, and
• the content of the resin in the total solid content of the actinic ray-sensitive or radiation-sensitive resin composition is 20 mass % or more, provided that, in the case where the repeating unit having an Si atom has a structure in which a polar group is protected by a leaving group capable of decomposing and leaving by the action of an acid and the leaving group has an Si atom, the amount of Si atoms in the leaving group is not included in the content of Si atoms in the resin.