Method for etching upper metal of capacitator

摘要

A method for etching an upper metal film of a capacitor, enables a safe etching of the upper metal film of a capacitor by exploiting an over-etch step. The method for etching the upper metal film of the capacitor includes the steps of forming a lower metal film, a lower nitride film, an upper metal film, and an upper nitride film on a substrate having a predetermined device formed thereon, and then forming a pattern thereover; etching the upper nitride film with CHF₃, Ar and Cl₂ using the pattern; over etching the upper metal film more than 50% with CHF₃, Ar and N₂ using the pattern; etching the upper metal film with CHF₃, Ar and N₂ using the pattern; and etching the lower nitride film with CHF₃ and Ar using the pattern.