Semiconductor Structure with Segmented Isolation for Stress Relief
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Solution Overview
Problem
Three-dimensional semiconductor structures face stress and distortion issues due to high aspect ratios in manufacturing processes, leading to device failure and mis-landing of contacts.
Innovation Solution
A semiconductor structure with sub-array structures separated by isolation structures, featuring conductive columns with circular cross sections that penetrate through the isolation structures, reducing interior stress by uniform stress distribution from insulating materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If openings with high aspect ratios are formed through the stack to create vertical structures, then three-dimensional memory structure is achieved, but interior stress and distortion increase leading to device failure
Solution Approach 1:
The patent divides the continuous isolation structure into discrete segments separated by air gaps. Each isolation structure is divided into multiple parts along the vertical direction, with air gaps between them. This segmentation reduces the continuous stress path and allows stress to be released at the air gap interfaces, preventing distortion and device failure while maintaining the three-dimensional memory structure.
Solution Approach 2:
The patent introduces air gaps at specific locations within the isolation structures, creating local void regions where stress can be relieved. These air gaps are strategically positioned to interrupt stress propagation paths without compromising the overall structural integrity. The local modification of having air gaps rather than solid material in specific regions allows stress management while maintaining the vertical memory structure.
2Ease of manufacture
If conventional isolation structures are used to separate sub-array structures, then manufacturing process is simplified, but stress concentration occurs leading to contact mis-landing
Solution Approach 1:
The isolation structures are segmented into multiple discrete parts separated by air gaps, which simplifies the manufacturing process by allowing independent formation and adjustment of each segment. This segmentation enables better control over stress distribution during fabrication, preventing stress-induced distortion that would cause contact mis-landing, while maintaining ease of manufacture through modular structure formation.
3Productivity
If high aspect ratio openings are used for vertical conductive structures, then device density is improved, but stress-induced distortion increases
Solution Approach 1:
Air gaps are introduced at specific locations within the isolation structures to locally relieve stress without affecting the overall high-density vertical structure. These localized void regions act as stress relief zones that prevent distortion propagation, allowing the maintenance of high aspect ratio openings for device density while compensating for stress-induced stability issues through strategic stress management points.
Data Source
AI summary
A semiconductor structure includes a plurality of sub-array structures separated from each other by a plurality of isolation structures. The semiconductor structure further includes a three-dimensional array of memory cells. The memory cells include a plurality of cell groups disposed in the sub-array structures, respectively. The semiconductor structure further includes a plurality of conductive structures. Each of the conductive structures includes a plurality of conductive columns correspondingly disposed in each of the isolation structures along an extending direction of the isolation structures. The conductive columns penetrate through the each of the isolation structures. Each of the conductive columns has a circular cross section.