3D Semiconductor Memory Stepwise Electrode Structure
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Solution Overview
Problem
The integration of two-dimensional semiconductor devices is limited by the expensive equipment required for fine pattern formation, which restricts the increase in memory cell density, necessitating the development of three-dimensional semiconductor memory devices with enhanced reliability and electrical characteristics.
Innovation Solution
A three-dimensional semiconductor memory device is designed with a substrate having a cell array region and a connection region, featuring a stepwise electrode structure with alternately stacked electrodes and dielectric layers, an etch stop pattern, and dummy patterns, which enhance electrical connections and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If two-dimensional semiconductor devices are used to achieve high integration, then manufacturing cost increases due to expensive fine pattern equipment, but device density and performance are limited
Solution Approach 1:
The patent transitions from two-dimensional planar memory cells to three-dimensional vertically stacked memory cells. Multiple memory cell strings are stacked along the vertical direction (third direction perpendicular to substrate), allowing significant increase in storage capacity without requiring proportionally smaller feature sizes or more expensive lithography equipment. The word line electrodes extend vertically through multiple stacked memory cell layers, enabling high-density storage with conventional manufacturing capabilities.
2Reliability
If three-dimensional electrode structure with stepwise configuration is implemented, then electrical connection reliability is improved, but manufacturing process complexity increases
Solution Approach 1:
The electrode structure is segmented into multiple functional regions: bit line electrodes, common source electrodes, and word line electrodes, each with specific geometries optimized for their function. The word line electrodes are further segmented into multiple stacked layers (first, second, third word line electrodes) separated by dielectric layers, allowing independent electrical control while maintaining structural organization. This segmentation enables reliable electrical connections through clearly defined conductive paths.
Solution Approach 2:
Dielectric layers are introduced as intermediary materials between conductive elements to provide electrical isolation and mechanical support. The dielectric layers fill spaces between stacked word line electrodes and between electrodes and substrates, ensuring proper electrical insulation while maintaining the three-dimensional structural integrity. This intermediary approach simplifies the manufacturing process by providing clear differentiation between conductive and insulating regions.
Data Source
AI summary
Disclosed are three-dimensional semiconductor memory devices and methods of fabricating the same. The three-dimensional semiconductor memory device comprises a substrate that includes a cell array region and a connection region, an electrode structure that includes a plurality of electrodes and a plurality of dielectric layers alternately stacked on the substrate and has a stepwise structure on the connection region, an etch stop pattern that covers the stepwise structure of the electrode structure. The electrode structure and the etch stop pattern extend in a first direction when viewed in plan. The electrode structure has a first width in a second direction intersecting the first direction. The etch stop pattern has a second width in the second direction. The second width is less than the first direction.