Patent ID: 9524976
Filing Date: 2016-12-20
CPC Classification: H01L

Claim Text:
1. A method of fabricating a memory device, comprising: forming a carbon etch stop layer having a first width dimension over a major surface of a substrate; forming a stack of alternating layers of a first material and a second material different from the first material over the carbon etch stop layer; etching the stack through a mask to the carbon etch stop layer to form a memory opening having a second width dimension at a bottom of the memory opening proximate to the carbon etch stop layer that is smaller than the first width dimension of the carbon etch stop layer; removing the carbon etch stop layer while not removing the first material and the second material to provide a void area between the bottom of the memory opening and a top surface of a protrusion comprising a semiconductor material, the void area having a larger width dimension than the second width dimension of the memory opening; forming at least a portion of a memory film over a sidewall of the memory opening and in the void area while each layer of the first material and each layer of the second material are present within the stack of alternating layers; and forming a semiconductor channel in the memory opening such that the memory film is located between the semiconductor channel and the sidewall of the memory opening wherein forming the carbon etch stop layer comprises: