US-20260129868-A1 - SINGLE ETCH AND PIER MERGE METHOD FOR CELL AND COMB FEATURES

US20260129868A1US 20260129868 A1US20260129868 A1US 20260129868A1US-20260129868-A1

Abstract

Methods, systems, and devices for single etch and pier merge method for cell and comb features are described. One or more pillars and one or more piers for a memory array may be patterned, aligned, and formed in one processing step. For example, the one or more piers and the one or more pillars may be patterned and etched using a pillar shape to form a set of pillar cavities. A first subset of the pillar cavities may be etched such that pairs of adjacent pillar cavities merge to form a pier cavity that is filled with a first material and a liner to form the one or more piers. A second subset of the pillar cavities may be filled with the liner and the first material to form the one or more pillars. Comb edge structures may be formed based on a third subset of the pillar cavities.

Inventors

Farrell M. Good
Trevor J. Plaisted

Assignees

MICRON TECHNOLOGY, INC.

Dates

Publication Date: 20260507
Application Date: 20251029

Claims (20)

1 . An apparatus, comprising: a substrate; a stack of materials comprising alternating layers of a first material and a second material; a plurality of piers extending through the stack of materials, wherein each pier of the plurality of piers is positioned above a third material that extends into the substrate; a plurality of pillars extending through the stack of materials, wherein each pillar of the plurality of pillars is positioned above a fourth material that extends into the substrate; and a plurality of comb edge structures extending through the stack of materials, wherein each comb edge structure of the plurality of comb edge structures is positioned above the third material, and wherein a portion of the first material extends, at each layer of the first material in the stack of materials, at least partially into a respective pier, a respective pillar, and a respective comb edge structure.
2 . The apparatus of claim 1 , wherein the plurality of comb edge structures comprises a first comb edge structure and a second comb edge structure, the plurality of pillars and the plurality of piers positioned between the first comb edge structure and the second comb edge structure.
3 . The apparatus of claim 1 , wherein the plurality of comb edge structures form a boundary of one or more comb structures, the one or more comb structures corresponding to one or more word lines.
4 . The apparatus of claim 1 , wherein a first pillar and a second pillar of the plurality of pillars are separated by a pier of the plurality of piers.
5 . The apparatus of claim 1 , wherein each of the plurality of pillars comprises the first material and a liner.
6 . The apparatus of claim 5 , wherein the liner comprises a silicon carbon nitride material.
7 . The apparatus of claim 1 , wherein the first material comprises a nitride material and the second material comprises an oxide material.
8 . The apparatus of claim 1 , wherein the third material comprises an aluminum oxide material or a tungsten material and the fourth material comprises a polysilicon material.
9 . A method, comprising: forming, through a stack of materials comprising alternating layers of a first material and a second material, a plurality of pillar cavities, the plurality of pillar cavities comprising a first set of pillar cavities associated with one or more comb edge structures, a second set of pillar cavities associated with one or more piers, and a third set of pillar cavities associated with one or more pillars; depositing a liner and the first material in each of the plurality of pillar cavities to form the one or more pillars within the third set of pillar cavities, the liner comprising a third material; applying a first masking material to the one or more pillars; removing, based at least in part on the first masking material, the liner and the first material in the first set of pillar cavities; removing, based at least in part on the first masking material, the liner and the first material in the second set of pillar cavities; depositing a fourth material in the first set of pillar cavities to form the one or more comb edge structures; and depositing a fifth material in the second set of pillar cavities to form the one or more piers.
10 . The method of claim 9 , further comprising: applying a second masking material to the one or more piers; and removing, based at least in part on the second masking material, the liner and the first material in the one or more pillars, wherein the one or more pillars are coupled with the one or more piers based at least in part on removing the liner and the first material in the one or more pillars.
11 . The method of claim 9 , further comprising: removing at least a portion of the second material in the first set of pillar cavities based at least in part on removing the liner and the first material in the first set of pillar cavities; removing at least a portion of the second material in the second set of pillar cavities based at least in part on removing the liner and the first material in the second set of pillar cavities; merging two or more adjacent pillar cavities of the first set of pillar cavities based at least in part on removing the portion of the second material in the first set of pillar cavities, wherein the one or more comb edge structures are formed based at least in part on merging the two or more adjacent pillar cavities; and merging adjacent pillar cavities of the second set of pillar cavities based at least in part on removing the portion of the second material in the second set of pillar cavities, wherein the one or more piers are formed based at least in part on merging the adjacent pillar cavities.
12 . The method of claim 11 , further comprising: removing at least a portion of the first material in the second set of pillar cavities, wherein merging the adjacent pillar cavities is based at least in part on removing the portion of the first material.
13 . The method of claim 11 , wherein the portion of the second material is removed via a buffered oxide etch process.
14 . The method of claim 9 , wherein removing the liner and the first material comprises: removing the first material in the first set of pillar cavities and in the second set of pillar cavities via a first etch process; and removing the liner via a second etch process.
15 . The method of claim 14 , wherein: the first etch process is associated with a wet etch process or vapor etch process, and the second etch process is associated with the vapor etch process.
16 . The method of claim 9 , further comprising: forming one or more comb structures based at least in part on forming the one or more comb edge structures, wherein the one or more comb structures correspond to one or more word lines.
17 . The method of claim 9 , wherein the first material and the liner in the first set of pillar cavities and the first material and the liner in the second set of pillar cavities are removed simultaneously.
18 . The method of claim 9 , wherein the first material comprises a nitride material and the second material comprises an oxide material.
19 . The method of claim 9 , wherein the third material comprises a silicon carbon nitride material and the fourth material comprises a dielectric material.
20 . An apparatus, comprising: one or more pillars; one or more piers; and one or more comb edge structures, wherein the one or more piers, the one or more pillars, and the one or more comb edge structures are formed by: forming, through a stack of materials comprising alternating layers of a first material and a second material, a plurality of pillar cavities, the plurality of pillar cavities comprising a first set of pillar cavities associated with the one or more comb edge structures, a second set of pillar cavities associated with the one or more piers, and a third set of pillar cavities associated with the one or more pillars; depositing a liner and the first material in each of the plurality of pillar cavities to form the one or more pillars within the third set of pillar cavities, the liner comprising a third material; applying a first masking material to the one or more pillars; removing, based at least in part on the first masking material, the liner and the first material in the first set of pillar cavities and in the second set of pillar cavities; and depositing a fourth material in the first set of pillar cavities to form the one or more comb edge structures and a fifth material in the second set of pillar cavities to form the one or more piers.

Description

CROSS REFERENCE The present Application for Patent claims priority to U.S. Patent Application No. 63/716,589 by Good et al., entitled “SINGLE ETCH AND PIER MERGE METHOD FOR CELL AND COMB FEATURES,” filed November 05, 2024, which is assigned to the assignee hereof, and which is expressly incorporated by reference in its entirety herein. TECHNICAL FIELD The following relates to one or more systems for memory, including single etch and pier merge method for cell and comb features. BACKGROUND Memory devices are widely used to store information in devices such as computers, user devices, wireless communication devices, cameras, digital displays, and others. Information is stored by programming memory cells within a memory device to various states. For example, binary memory cells may be programmed to one of two supported states, often denoted by a logic 1 or a logic 0. In some examples, a single memory cell may support more than two states, any one of which may be stored. To access the stored information, the memory device may read (e.g., sense, detect, retrieve, determine) states from the memory cells. To store information, the memory device may write (e.g., program, set, assign) states to the memory cells. Various types of memory devices exist, including magnetic hard disks, random access memory (RAM), read-only memory (ROM), dynamic RAM (DRAM), synchronous dynamic RAM (SDRAM), static RAM (SRAM), ferroelectric RAM (FeRAM), magnetic RAM (MRAM), resistive RAM (RRAM), flash memory, phase change memory (PCM), self-selecting memory, chalcogenide memory technologies, not-or (NOR) and not-and (NAND) memory devices, and others. Memory cells may be described in terms of volatile configurations or non-volatile configurations. Memory cells configured in a non-volatile configuration may maintain stored logic states for extended periods of time even in the absence of an external power source. Memory cells configured in a volatile configuration may lose stored states when disconnected from an external power source. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an example of a memory array that supports a single etch and pier merge method for cell and comb features in accordance with examples as disclosed herein. FIG. 2 shows a top view of an example of a memory array that supports a single etch and pier merge method for cell and comb features in accordance with examples as disclosed herein. FIGS. 3A and 3B show side views of an example of a memory array that supports a single etch and pier merge method for cell and comb features in accordance with examples as disclosed herein. FIGS. 4 through 9 show examples of processing steps of a single etch and pier merge method for cell and comb features in accordance with examples as disclosed herein. FIG. 10 shows examples of cross-sectional views that support single etch and pier merge method for cell and comb features in accordance with examples as disclosed herein. FIGS. 11A and 11B show examples of elevation views that supports a single etch and pier merge method for cell and comb features in accordance with examples as disclosed herein. FIG. 12 shows a flowchart illustrating a method or methods that support single etch and pier merge method for cell and comb features in accordance with examples as disclosed herein. DETAILED DESCRIPTION In some memory architectures, an array of memory cells may be formed by etching a stack of materials multiple times (e.g., at least twice). For example, one or more piers may be patterned and formed in a first processing step that includes a first etching process, and one or more pillars may be patterned and formed in a second processing step that includes a second etching process. The piers may form one or more first access lines (e.g., bit lines) to access memory cells in the array. In such memory architectures, the etching processes may be optimized for circular shapes, resulting in challenges for forming the one or more piers (e.g., which may be generally elliptical shaped) using the first etching process. For example, as the density of memory cells in the array increases, the accuracy of the first etching process along an axis of an elliptical-shaped pier may degrade. That is, methods of forming generally elliptical shaped piers may not scale with higher densities of memory cells. Thus, a method to reliably form generally elliptical shaped piers may be desirable. The techniques described herein enable one or more pillars and one or more piers to be patterned, aligned, and formed in fewer processing steps (e.g., one processing step) relative to conventional methods. For example, the one or more piers and the one or more pillars may be patterned using a pillar shape (e.g., a circular shape) to form a set of pillar cavities. A first subset of the pillar cavities may be etched such that pairs of pillar cavities merge to form a pier cavity that is filled with a first material and a liner to form the one or more piers. A second subset of the pilla