Vertical Memory Etch Stop Structure for COP Short Isolation
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Solution Overview
Problem
In VNAND flash memory devices with a cell-over-periphery (COP) structure, the formation of insulation patterns and etch stop structures is challenging, leading to potential electrical shorts and structural instability during manufacturing, which can result in the device leaning or falling down.
Innovation Solution
A vertical memory device design that includes a gate electrode structure, channel, insulation pattern structure, etch stop structure, and through via, where the etch stop structure surrounds the insulation pattern and has a closed ring shape in a plan view, with specific division patterns and support layers to prevent electrical shorts and structural instability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If insulation pattern structure is formed to extend through gate electrode structure, then electrical connection between lower circuit pattern and upper structure is achieved, but electrical shorts between gate electrodes may occur
Solution Approach 1:
An etch stop structure is introduced as an intermediary element between the insulation pattern structure and the gate electrodes. This etch stop structure extends through the gate electrode structure and surrounds the insulation pattern structure, acting as a protective barrier that prevents direct contact between conductive elements, thereby eliminating electrical shorts while maintaining the desired electrical connections.
Solution Approach 2:
The etch stop structure is divided into multiple patterns containing different materials from each other. This segmentation allows different portions of the etch stop structure to perform different functions: some portions provide electrical isolation, while others provide structural support. The multi-material composition enables precise control over where electrical connections are permitted and where isolation is enforced.
2Reliability
If through via is formed to extend through insulation pattern structure for electrical connection, then lower circuit pattern is electrically connected, but structural stability may be compromised causing device to lean or fall
Solution Approach 1:
The etch stop structure is segmented into multiple patterns with different materials, creating a reinforced composite structure. This segmented design provides both electrical isolation and mechanical support, preventing the device from leaning or falling while allowing the through via to maintain electrical connections.
Solution Approach 2:
The etch stop structure comprises multiple patterns containing different materials from each other, forming a composite structure. This composite design combines materials with different properties to simultaneously achieve electrical isolation, mechanical strength, and structural stability, preventing device failure while enabling necessary electrical connections.
3Reliability
If etch stop structure surrounds insulation pattern structure with closed ring shape, then electrical shorts are prevented, but manufacturing complexity increases
Solution Approach 1:
The etch stop structure serves multiple functions simultaneously: it provides electrical isolation between gate electrodes, offers structural support to prevent device failure, and acts as a formation guide for the insulation pattern structure. By combining multiple functions into a single structure, the design achieves reliable electrical isolation without proportionally increasing manufacturing complexity.
Data Source
AI summary
A vertical memory device includes a gate electrode structure, a channel, an insulation pattern structure, an etch stop structure, and a through via. The gate electrode structure includes gate electrodes spaced apart from each other on a substrate in a first direction perpendicular to an upper surface of the substrate, and each of the gate electrodes extends in a second direction parallel to the upper surface of the substrate. The channel extends in the first direction through the gate electrode structure. The insulation pattern structure extends through the gate electrode structure. The etch stop structure extends through the gate electrode structure and surround at least a portion of a sidewall of the insulation pattern structure, and the etch stop structure includes a filling pattern and an etch stop pattern on a sidewall of the filling pattern. The through via extends in the first direction through the insulation pattern structure.