Sandisk Technologies Inc.

Sandisk 3d LLC

Hiroaki Iuchi

Naoki Takeguchi

Keisuke Izumi

Akio Yanai

Hitomi Fujimoto

Michiaki Sano

Chao Feng Yeh

Ryo Taura

Kentaro Sera

Hiroyuki Ogawa

Tuan Duc Pham

Masatoshi Nishikawa

Kiyohiko Sakakibara

Seiji Shimabukuro

Jongsun Sel

Kensuke Yamaguchi

Genta Mizuno

Atsushi Suyama

Kazutaka Yoshizawa

Yusuke Yoshida

Ryoichi Honma

Sayako Nagamine

Akira Nakada

Ming Tian

Xiaolong Hu

Naohito Yanagida

Chan Park

Masafumi Miyamoto

Takashi Kashimura

Hisayuki Nozawa

Frank Yu

Jiao Chen

Takehiro Yamazaki

Minoru Yamaguchi

Daisuke Maekawa

A vertical memory device including dual memory cells per level in each memory opening can have dielectric separator dielectric structures that protrude into a facing pair of sidewalls of the memory stack structure within the memory opening. A pair of inactive sections of a vertical semiconductor channel facing the dielectric separator dielectric structures is laterally recessed from control gate electrodes. Control of the threshold voltage of such a vertical memory device can be enhanced because of the dielectric separator dielectric structures. The fringe field from the control gate electrodes is weaker due to an increased distance between the control gate electrodes and the inactive sections of the vertical semiconductor channel. The memory stack structure can have concave sidewalls that contact the dielectric separator dielectric structures and convex sidewalls that protrude toward the control gate electrodes.

3D semicircular vertical NAND string with recessed inactive semiconductor channel sections

Three-dimensional (3D) non-volatile memory arrays having a vertically-oriented thin film transistor (TFT) select device and method of fabricating are described. The vertically-oriented TFT may be used as a vertical bit line selection device to couple a global bit line to a vertical bit line. A select device pillar includes a body and upper and lower source/drain regions. At least one gate is separated horizontally from the select device pillar by a gate dielectric. Each gate is formed over the gate dielectric and a base that extends horizontally at least partially between adjacent pillars. The base is formed with notches filled with the gate dielectric. The select device is fabricated using a conformally deposited base dielectric material and conformal hard mask layer that is formed with a larger bottom thickness than horizontal thickness. The base thickness is defined by the deposition thickness, rather than an uncontrolled etch back.

Vertical thin film transistors in non-volatile storage systems

A trench can be formed through a stack of alternating plurality of first material layers and second material layers. A dielectric material liner and a trench fill material portion can be formed in the trench. The dielectric material liner and portions of first material layer can be simultaneously etched to form laterally-extending cavities having level-dependent lateral extents. A set of stepped surfaces can be formed by removing unmasked portions of the second material layers. Alternately, an alternating sequence of processing steps including vertical etch processes and lateral recess processes can be employed to laterally recess second material layers and to form laterally-extending cavities having level-dependent lateral extents. Lateral cavities can be simultaneously formed in multiple levels such that levels having laterally-extending cavities of a same lateral extent are offset across multiple integrated cavities.

Set of stepped surfaces formation for a multilevel interconnect structure

Contact openings extending to sacrificial layers located at different depths can be formed by sequentially exposing a greater number of openings in a mask layer by iterative alternation of trimming of a slimming layer over the mask layer and an anisotropic etch that recesses pre-existing contact openings by one level. In one embodiment, pairs of an electrically conductive via contact and electrically conductive electrodes can be simultaneously formed as integrated line and via structures. In another embodiment, encapsulated unfilled cavities can be formed in the contact openings by non-conformal deposition of a material layer, electrically conductive electrodes can be formed by replacement of portions of the sacrificial layers, and the electrically conductive via contacts can be subsequently formed on the electrically conductive electrodes. Electrically conductive via contacts extending to electrically conductive electrodes located at different level can be provided with self-aligned insulating liner.

Multiheight contact via structures for a multilevel interconnect structure

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

Non-volatile storage devices and methods for fabricating non-volatile storage device are described. Sidewalls of the memory cells and their associated word line may be covered with silicon oxide. Silicon nitride covers the silicon oxide adjacent to the word lines, which may provide protection for the word lines during fabrication. However, silicon nitride can trap charges, which can degrade operation if the trapped charges are near a charge trapping region of a memory cell. Thus, the silicon nitride does not cover the silicon oxide adjacent to charge storage regions of the memory cells, which can improve device operation. For example, memory cell current may be increased. Techniques for forming such a device are also disclosed. One aspect includes a method that uses a sacrificial material to control formation of a silicon nitride layer when forming a memory device.

Non-volatile storage having oxide/nitride sidewall

Multiheight electrically conductive via contacts for a multilevel interconnect structure

Electrical isolation in non-volatile memory is provided by air gaps formed using sacrificial films of differing etch rates. A high etch rate material is formed in an isolation trench. Flowable chemical vapor deposition processes are used to form high etch rate films, and curing is performed to increase their etch rate. A low etch material is formed over the high etch rate material and provides a controlled etch back between charge storage regions in a row direction. A discrete low etch rate layer can be formed or the high etch rate material can be oxidized to form an upper region with a lower etch rate. A controlled etch back enables formation of a wrap-around dielectric and control gate structure in the row direction with minimized variability in the dimensions of the structures. At least a portion of the high etch rate material is removed to form air gaps for isolation.

Air gap isolation in non-volatile memory using sacrificial films

Techniques disclosed herein may achieve crack free filling of structures. A flowable film may substantially fill gaps in a structure and extend over a base in an open area adjacent to the structure. The top surface of the flowable film in the open area may slope down and may be lower than top surfaces of the structure. A capping layer having compressive stress may be formed over the flowable film. The bottom surface of the capping layer in the open area adjacent to the structure is lower than the top surfaces of the lines and may be formed on the downward slope of the flowable film. The flowable film is cured after forming the capping layer, which increases tensile stress of the flowable film. The compressive stress of the capping layer counteracts the tensile stress of the flowable film, which may prevent a crack from forming in the base.

Method of forming crack free gap fill

Techniques disclosed herein prevent wire flaking (collapse). One aspect is an improved way of forming wires over trenches, which may be located in a hookup region of a 3D memory array, and may be used to form electrical connections between conductive lines in the memory array and drivers. The trenches are formed between CMP dummy structures. The trenches are partially filled with a flowable oxide film, which leaves a gap in the trench that is at least as wide as the total pitch of the wires to be formed. A capping layer is formed over the flowable film. After forming a conductive layer over the dielectric layer, the conductive layer is etched to form conductive wires. Some of the capping layer, as well as the CMP dummy structures may be removed. Thus, the conductive wires may be at least temporarily supported by lines of material formed from the capping layer.

Method of inhibiting wire collapse

Growing community of inventors

Nagoya, Japan

Hiroaki Iuchi