Sandisk Technologies Inc.

Chan Park

Tuan Duc Pham

Naoki Takeguchi

Jong Sun Sel

Marika Gunji-Yoneoka

Kazuya Tokunaga

Hiroyuki Ogawa

Kiyohiko Sakakibara

Jongsun Sel

Kensuke Yamaguchi

Atsushi Suyama

Hiroaki Iuchi

Ryoichi Honma

Frank Yu

Jiao Chen

In a three dimensional nonvolatile memory, memory holes extend vertically through two or more physical levels in which memory cells are formed. Memory hole structures are formed in memory holes to include vertical channels. Vertical trenches are subsequently formed to divide memory hole structures into two or more vertical NAND strings.

Memory hole structure in three dimensional memory

An alternating stack of insulating layers and sacrificial material layers is formed over a substrate. After formation of a memory opening, all surfaces of the memory opening are provided as silicon oxide surfaces by formation of at least one silicon oxide portion. A silicon nitride layer is formed in the memory opening. After formation of a memory stack structure, backside recesses can be formed employing the silicon oxide portions as an etch stop. The silicon oxide portions can be subsequently removed employing the silicon nitride layer as an etch stop. Physically exposed portions of the silicon nitride layer can be removed selective to the memory stack structure. Damage to the outer layer of the memory stack structure can be minimized or eliminated by successive use of etch stop structures. Electrically conductive layers can be subsequently formed in the backside recesses.

Blocking oxide in memory opening integration scheme for three-dimensional memory structure

Air gaps are formed between bit lines by etching to remove sacrificial material from between bit lines. Bit lines are protected from etch damage. Sacrificial material may be selectively oxidized prior to deposition of bit line metal so that protective oxide lies along sides of bit lines during etch. Portions of protective material may be selectively formed on tops of bit lines prior to etching sacrificial material.

Air gap formation between bit lines with side protection

Air gap formation between bit lines with top protection

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Mountain View, CA, United States of America

Chan Park