Methods for forming hole structure in semiconductor device

Abstract

Embodiments of the present disclosure provide a method for forming a hole structure in a semiconductor device. The method for forming a hole structure having a first hole portion and a second hole portion connected to and over the first portion in a stack structure of a semiconductor device includes determining a hard mask layer. An etching resistivity of the hard mask layer may be inversely proportional to a difference between a first lateral dimension of the first hole portion and a second lateral dimension of the second hole portion, and the first lateral dimension may be less than the second lateral dimension. The method may also include forming the hard mask layer over the stack structure, and patterning the hard mask layer to form a first patterned hard mask layer that has a first mask opening. The first mask opening may have the first lateral dimension. The method may further include removing a portion of the stack structure exposed by the first patterned hard mask layer to form an initial hole structure in the stack structure, and patterning the first patterned hard mask layer to form a second patterned mask layer that has a second mask opening. The second mask opening may have the second lateral dimension. The method may further include removing another portion of the stack structure exposed by the second patterned hard mask layer to form the hole structure.