3D Memory Gate Stack Support Slits for Replacement Stability
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Solution Overview
Problem
In the manufacturing of three-dimensional memory devices, existing methods face challenges in maintaining the structural integrity of gate stack structures during the replacement process, often resulting in bending or collapse due to the absence of adequate support structures.
Innovation Solution
The method involves forming a first slit trench between adjacent tile regions before creating second slit trenches, utilizing the first slit as a support structure to prevent the bending or collapse of gate stack structures during the replacement of sacrificial layers with gate conductive layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sacrificial layers are replaced with gate conductive layers in three-dimensional memory devices, then the gate stack structures can be formed, but the gate stack structures may bend or collapse due to lack of support during the replacement process
Solution Approach 1:
The patent applies preliminary action by forming support structures (first and second support structures) before the replacement of sacrificial layers with gate conductive layers. These support structures are created in advance to prevent bending or collapse of gate stack structures during the replacement process, ensuring structural integrity is maintained throughout manufacturing
Solution Approach 2:
The patent uses intermediary support structures that act as temporary mediators during the replacement process. The first support structure extends from the substrate to the stacked structure, and the second support structure connects the first support structure to the stacked structure, serving as intermediate elements that provide necessary support without being part of the final device functionality
Data Source
AI summary
A method of fabricating a memory device includes patterning a stacked structure to form a first staircase structure and a second staircase structure; patterning a conductive layer under the stacked structure to form a first slit trench along a first direction; forming a first dielectric layer overlaying the first staircase structure and the second staircase structure and filling into the first slit trench, wherein the first dielectric layer filled in the first slit trench forms a first slit; patterning the first dielectric layer, the stacked structure, and the conductive layer to form multiple second slit trenches, wherein the second slit trenches along a second direction perpendicular to the first direction; performing a replacement process to replace the sacrificial layers with multiple gate conductive layers; and filling a second dielectric layer in the second slit trenches to form multiple second slits.