PURPOSE: To provide an electric insulating material having a high heat resistance and low dielectric constant and also an inter-layer insulative film and to provide a method for forming the inter-layer insulative film.

CONSTITUTION: An electric insulating material chiefly contains at least one of the no-metal phthalocyanine or silicon phthalocyanine of such a structure that at least one of the hydrogen atoms bonded with an aromatic ring in the molecule is substituted with fluorine atom and the non-metal naphthalocyanine or silicon naphthalocyanine of such a structure that at least one of the hydrogen atoms bonded with the aromatic ring in the molecule is substituted with fluorine atom. An inter-layer insulative film is made from this insulating material, and a method for forming it consists of subjecting the insulating material to a plasma polymerization process.