Vertical Memory Ground Select Line Leakage Prevention
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Solution Overview
Problem
The integration density of two-dimensional memory devices is limited by the need for expensive equipment to form fine patterns and the limited area of chip dies, leading to a demand for vertical memory devices with a three-dimensional structure.
Innovation Solution
The development of an integrated circuit device with a vertical memory device, where the occurrence of leakage current through dummy contact plugs is inhibited by forming a ground select line with a relatively short horizontal length in the connection region where the dummy contact plug is arranged.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a vertical memory device structure is adopted to increase integration density, then the integration density is improved, but the risk of leakage current through dummy contact plugs increases
Solution Approach 1:
The ground select line is extended in the horizontal direction in advance within the connection region to create a preliminary protective structure. This extension is performed before the dummy contact plug formation, ensuring that the ground select line is already positioned to intercept and prevent leakage current paths that may form through the dummy contact plugs, thus proactively addressing the reliability issue while maintaining high integration density
Solution Approach 2:
The ground select line acts as an intermediary element between the dummy contact plug and the channel structure. By extending the ground select line horizontally, it serves as a mediating conductive path that provides a controlled electrical connection to ground, preventing uncontrolled leakage current from reaching the channel structure through the dummy contact plug, thus resolving the contradiction between integration density and leakage prevention
2Reliability
If the ground select line is extended horizontally to prevent leakage current, then the leakage current is inhibited, but the manufacturing complexity increases
Solution Approach 1:
The ground select line extension is merged with the existing gate electrode structure in the connection region. Instead of creating a separate protective structure, the ground select line itself is extended to serve dual purposes: maintaining its original vertical memory function and providing horizontal leakage current prevention, thus improving reliability without significantly increasing device complexity
Solution Approach 2:
The ground select line is designed to perform multiple functions simultaneously: it maintains its role in the vertical memory device operation while its horizontal extension provides an additional function of preventing leakage current through dummy contact plugs. This multi-functionality approach allows the same structure to address both memory functionality and reliability concerns without adding separate dedicated structures
Data Source
AI summary
An integrated circuit device according to the inventive concept includes: a semiconductor substrate including a cell region and a connection region; a gate stack including a plurality of gate electrodes and a plurality of insulating layers extending on a main surface of the semiconductor substrate in a horizontal direction and alternately stacked thereon in a vertical direction, the gate stack having a stair structure in the connection region; and a plurality of contact plugs in the connection region, wherein, in a portion of the connection region, a first length, in the horizontal direction, of a first gate electrode that is located in the lowest layer among the plurality of gate electrodes is less than a second length, in the horizontal direction, of a second gate electrode that is located above the first gate electrode.