Patent ID: 8658053

Claim:
An etchant composition having a property of selectively etching a metallic material in production of a semiconductor device from an insulating material having high dielectric constant, an insulating material of silicon oxide film or silicon nitride film, and the metallic material, characterized in that the etchant composition is an aqueous solution containing a fluorine compound, a chelating agent having, in a molecular structure thereof, a phosphorus oxo-acid as a functional group, and at least one of an inorganic acid and an organic acid, wherein when the inorganic acid is contained in the aqueous solution, the inorganic acid is contained in an amount of 50% by mass or less, and when the organic acid is contained in the aqueous solution, the organic acid is contained in an amount of 15% by mass or less, and wherein said chelating agent is at least one selected from the group consisting of diphosphonic acids, nitrilomethylenephosphonic acids and pentamethylenephosphonic acids, wherein the inorganic acid, when contained in the aqueous solution, is contained in an amount with a range of 5 to 50% by mass, and the organic acid, when contained in the aqueous solution, is contained in an amount within a range of 3 to 15% by mass, wherein the amount of the fluorine compound is 0.5 to 10mass %.