Segmented Gate Line Isolation for High-Density 3D Memory
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Solution Overview
Problem
The manufacturing of high-density 3D memory devices faces challenges such as stress issues, X-Y bow problems in conductive layer filling, component tilting or collapse, and overlay issues due to the large number of layers and high aspect ratios, which affect the reliability and yield of the fabrication process.
Innovation Solution
Incorporation of isolation structures that separate gate line structures into segments, allowing for separate conductive layer filling processes and reducing stress, while maintaining electrical functionality and avoiding seam formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of layers is increased to increase array density, then storage capacity is improved, but stress issues and overlay problems worsen
Solution Approach 1:
The gate line structure is divided into multiple segments separated by isolation structures. This segmentation allows independent conductive layer filling for each segment, reducing stress accumulation and preventing overlay issues that would otherwise occur with continuous gate lines across many layers.
Solution Approach 2:
Isolation structures are introduced in the lateral dimension to segment the gate line structure. This adds a new dimensional approach to solving the multi-layer stress problem, rather than only addressing it through vertical layer stacking.
2Reliability
If continuous gate line structure is used, then electrical connectivity is improved, but stress accumulation and overlay issues worsen
Solution Approach 1:
The gate line is segmented into multiple sections by isolation structures, allowing each segment to be independently formed with precise overlay control. This prevents the cumulative overlay errors that would occur in a single continuous gate line structure across many layers.
Solution Approach 2:
Isolation structures serve as intermediary elements between gate line segments. These intermediaries provide physical separation and stress relief while allowing electrical connectivity to be maintained through the conductive layers that extend across the isolation structures.
3Productivity
If isolation structures are introduced to reduce stress, then fabrication yield is improved, but device complexity increases
Solution Approach 1:
The gate line structure is segmented into multiple sections by isolation structures. This segmentation allows independent conductive layer filling for each segment, reducing stress accumulation and preventing overlay issues that would otherwise occur with continuous gate lines across many layers.
Solution Approach 2:
The isolation structures serve multiple functions: they provide stress relief, enable segmentation for better overlay control, and allow independent processing of different gate line segments. This multi-functionality justifies the added structural complexity by delivering multiple benefits simultaneously.
Data Source
AI summary
The present disclosure relates to methods, devices, systems, and techniques for managing isolation structures in semiconductor devices. An example semiconductor device includes an array region, a connection region, and a stack of conductive layers and insulating layers alternating with each other along a first direction. The semiconductor device further includes a gate line structure having at least a first segment and a second segment. The gate line structure extends along a second direction perpendicular to the first direction. The semiconductor device further includes an isolation structure separating the first segment from the second segment. A size of the isolation structure in a third direction is same as a size of the first segment in the third direction. The third direction is perpendicular to the first direction and the second direction.