3D NAND Stacked Structure Dummy Segmentation for Tilting Prevention
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Solution Overview
Problem
The manufacturing process of three-dimensional non-volatile memory devices is challenging due to the difficulty in replacing nitride layers with conductive layers without causing structural tilting or collapse.
Innovation Solution
A semiconductor device with alternately stacked conductive and insulating layers, including dummy structures in different regions, is designed to maintain structural stability, with specific patterning and trench formation techniques to prevent stress and deformation during the replacement process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nitride layers are replaced with conductive layers in three-dimensional stacked structures, then device functionality is achieved, but structural tilting or collapse occurs
Solution Approach 1:
The patent divides the stacked structure into multiple regions with different dummy structure configurations. Specifically, first dummy structures are placed in first regions and second dummy structures are placed in second regions, creating segmented zones that manage stress distribution differently across the device. This segmentation allows the structure to maintain stability during the challenging replacement process while achieving the required functionality.
Solution Approach 2:
The patent applies local quality by creating region-specific dummy structures with different characteristics. The first dummy structures in first regions have different configurations compared to the second dummy structures in second regions. This local differentiation allows targeted stress management in different areas of the stacked structure, preventing tilting and collapse during the replacement of nitride layers with conductive layers.
2Productivity
If three-dimensional stacked structures are used to increase integration, then device density is improved, but manufacturing complexity increases
Solution Approach 1:
By segmenting the device into regions with different dummy structure types, the patent manages the complexity of three-dimensional stacked structures. The segmentation strategy allows each region to be optimized independently, making the overall manufacturing process more manageable while maintaining high integration density through vertical stacking.
Solution Approach 2:
The dummy structures are prepared and positioned in advance before the critical replacement process. This preliminary action of placing appropriately configured dummy structures in specific regions beforehand prevents structural issues during the actual replacement of nitride layers, simplifying the manufacturing process while enabling three-dimensional integration.
Data Source
AI summary
A semiconductor device includes a substrate having a cell region, wherein a contact region, page buffer regions, and a scribe lane region are defined around the cell region; a cell structure located in the cell region, including first conductive layers and first insulating layers which are alternately stacked, and having a non-stepped shape; a contact structure located in the contact region, including second conductive layers and second insulating layers which are alternately stacked, and having a stepped shape; a first dummy structure located in the page buffer region, including first sacrificial layers and third insulating layers which are alternately stacked, and having the non-stepped shape; and a second dummy structure located in the scribe lane region, including second sacrificial layers and fourth insulating layers which are alternately stacked, and having the stepped shape.