Method for fabricating semiconductor device with damascene structure by using etch stop layer

Abstract

The present application discloses a method for fabricating a semiconductor device including: providing a photomask including an opaque layer on a mask substrate and surrounding a translucent layer on the mask substrate; forming a pre-process mask layer on a device stack; patterning the pre-process mask layer using the photomask to form a patterned mask layer including a mask region corresponding to the opaque layer, a trench region corresponding to the translucent layer, and a via hole corresponding to the mask opening of via feature; performing a damascene etching process to form a via opening and a trench opening in the device stack. The device stack includes a first dielectric layer on a substrate, a first etch stop layer on the first dielectric layer, and a second dielectric layer on the first etch stop layer. The damascene etching process forms the trench opening having a bottom on the first etch stop layer.