Three-dimensional memory device and manufacturing method thereof

Abstract

A method for manufacturing three-dimensional memory, comprising the steps of: forming a stack structure composed of a plurality of first material layers and a plurality of second material layers on a substrate; etching the stack structure to expose the substrate, forming a plurality of first vertical openings; forming a filling layer in each of the first openings; etching the stack structure around each of the first openings to expose the substrate, forming a plurality of second vertical openings; forming a vertical channel layer and a drain in each of the second openings; removing the filling layer by selective etching, re-exposing the first openings; partially or completely removing the second material layers by lateral etching, leaving a plurality of recesses; forming a plurality of gate stack structure in the recesses; forming a plurality of common sources on and/or in the substrate at the bottom of each of the first openings. In accordance with the three-dimensional memory manufacturing method of the present invention, the deep trenches of word-line in the TCAT three-dimensional device are replaced with deep-hole etching to realize the same function, thereby improving the integration density, simplifying the etching process of stacked structure, and maintaining the control performance of the metal gate.