Method for forming gate of semiconductor device

Abstract

Disclosed is a method for forming a gate of a semiconductor device capable of preventing a bridge from being created between adjacent gates due to a nitride polymer. The method includes the steps of forming a gate oxide film, a gate poly-Si film, and a gate W film successively on a semiconductor substrate; forming a pure SiN film and an oxide-rich SiN film successively on the gate W film as hard mask films; forming an oxide-rich SiON film on the oxide-rich SiN film as an anti-reflective coating film; patterning the oxide-rich SiON film, the oxide-rich SiN film, and the pure SiN film into the shape of a gate; and etching the gate W film, the gate poly-Si film, and the gate oxide film successively using the patterned pure SiN film as an etching barrier.