Segmented Slit Memory Stack Structure for Bending Control
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Solution Overview
Problem
The increasing number of stacked layers in memory devices leads to severe bending issues, potentially causing short circuits between the bit line and the top word line, which affects the operation and reliability of the memory device.
Innovation Solution
The introduction of a memory device design where a slit between two sets of vertical channel structures is divided into multiple sub-slits to enhance mechanical strength, reducing bending issues during manufacturing processes such as wet etching and film deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of stacked layers is increased to achieve high storage density, then the storage capacity is improved, but the bending issue of the composite film stack becomes more serious
Solution Approach 1:
The continuous slit structure is divided into multiple discrete sub-slits arranged along the X direction. This segmentation allows the slit to provide stress relief and reduce bending while maintaining the electrical isolation function. The discrete sub-slits prevent the continuous stress concentration that would occur in a single long slit, thereby reducing the bending issue in high-density stacked memory devices
2Quantity of substance
If the number of stacked layers is increased to achieve high storage density, then the storage capacity is improved, but the risk of short circuit between bit line and top word line increases
Solution Approach 1:
The continuous slit is segmented into multiple discrete sub-slits that are spaced apart along the X direction. This segmentation maintains the electrical isolation between the bit line and top word line while reducing the continuous stress path that could lead to bending-induced short circuits. The discrete structure provides multiple isolation points without creating a single point of failure
3Reliability
If a continuous slit is used to isolate vertical channel structures, then the electrical isolation is achieved, but the mechanical strength is reduced due to bending
Solution Approach 1:
The continuous slit is divided into multiple discrete sub-slits arranged along the X direction. Each sub-slit provides local electrical isolation while the gaps between sub-slits allow the composite film stack to better distribute and relieve stress. This segmentation maintains the necessary electrical isolation function while significantly improving the mechanical strength and reducing bending issues
Data Source
AI summary
Provided is a memory device including a stack structure, a first set of vertical channel structures, a second set of vertical channel structures and a first slit. The stack structure is disposed on a substrate, wherein a top surface of the substrate is parallel to a plane defined by a X direction and a Y direction perpendicular to the X direction. The first set of vertical channel structures and the second set of vertical channel structures are arranged along the Y direction and penetrating through the stack structure along a Z direction vertical to the plane to contact the substrate. The first slit is disposed between the first and second sets of vertical channel structures, and penetrates through the stack structure along the Z direction to expose the substrate, wherein the first slit includes a plurality of first sub-slits discretely disposed along the X direction.