3D Semiconductor Memory Vertical Insulating Layers
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Solution Overview
Problem
Current two-dimensional semiconductor memory devices face limitations in integration and cost due to expensive process equipment for fine pattern formation, hindering increased integration and mass production of three-dimensional semiconductor memory devices with improved reliability and productivity.
Innovation Solution
A three-dimensional semiconductor memory device is fabricated with a specific electrode structure, including a lower electrode with stacked conductive layers, vertical and horizontal insulating layers, and semiconductor patterns, along with a method involving the formation of a mold structure, sacrificial layers, and sequential deposition of insulating and semiconductor layers to create a high-density memory device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If two-dimensional or planar semiconductor memory devices are used, then manufacturing process is simpler, but integration is limited due to area constraints and expensive fine pattern forming equipment
Solution Approach 1:
The patent transitions from two-dimensional planar memory devices to three-dimensional vertically stacked memory devices. Multiple memory cell layers are stacked in the vertical direction, with each layer containing memory cells formed by intersecting word lines and bit lines. This dimensional change increases integration density without requiring proportionally more expensive fine pattern forming equipment, as the stacking approach leverages existing process capabilities in the vertical domain.
2Productivity
If three-dimensional semiconductor memory devices are fabricated, then integration and productivity increase, but manufacturing cost and reliability challenges arise
Solution Approach 1:
The three-dimensional memory device is segmented into multiple discrete memory cell layers stacked vertically. Each layer is formed through a modular process sequence involving alternating deposition of insulating layers and conductive patterns. This segmentation allows for standardized replication of layers, improving manufacturing efficiency and productivity while enabling systematic quality control and reliability assessment for each layer.
Solution Approach 2:
The patent employs preliminary formation of insulating layers and sacrificial structures before final memory cell formation. Mold structures and sacrificial layers are deposited and patterned in advance to define the three-dimensional architecture, enabling subsequent semiconductor layers to be formed with proper spacing and alignment. This preliminary action ensures structural integrity and reduces defects, thereby improving reliability.
3Manufacturing precision
If fine pattern forming technology is advanced to increase integration, then more memory cells fit in planar devices, but process equipment cost increases significantly
Solution Approach 1:
Instead of increasing pattern fineness in the planar direction, the patent utilizes the vertical dimension to achieve higher integration. Multiple memory cell layers are stacked with thicknesses on the order of micrometers, which can be formed using conventional deposition and etching equipment. This approach achieves high integration density without requiring the extremely expensive fine pattern forming equipment needed for sub-micrometer planar scaling.
Data Source
AI summary
Example embodiments relate to a three-dimensional semiconductor memory device including an electrode structure on a substrate, the electrode structure including at least one conductive pattern on a lower electrode, and a semiconductor pattern extending through the electrode structure to the substrate. A vertical insulating layer may be between the semiconductor pattern and the electrode structure, and a lower insulating layer may be between the lower electrode and the substrate. The lower insulating layer may be between a bottom surface of the vertical insulating layer and a top surface of the substrate. Example embodiments related to methods for fabricating the foregoing three-dimensional semiconductor memory device.