3D Capacitor Structure for Semiconductor Memory Devices
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Solution Overview
Problem
Three-dimensional semiconductor memory devices face challenges in achieving optimal performance due to insufficient capacitance, which is a result of reduced form factor and increased density of memory cells in a limited area, leading to inadequate chip performance.
Innovation Solution
The semiconductor memory device incorporates a capacitor structure spaced apart from a source structure on a substrate, with interlayer insulating and sacrificial layers, and a dummy stack structure, allowing for increased capacitance without expanding chip size through the use of doped semiconductor layers and conductive patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If memory cells are densely arranged in a limited area to increase integration density, then chip size is reduced, but capacitance becomes insufficient for optimal performance
Solution Approach 1:
The patent transitions from two-dimensional planar capacitor layout to three-dimensional vertical stacking. Capacitor structures are formed as stacked layers extending in the vertical direction above the substrate, utilizing the third dimension (height) to increase capacitance without occupying additional horizontal chip area. This dimensional transition allows sufficient capacitance to be achieved while maintaining high memory cell density in the limited planar space.
2Area of stationary object
If chip size is reduced to increase memory cell density, then integration is improved, but capacitance becomes insufficient
Solution Approach 1:
The capacitor structures are configured to extend vertically in the third dimension above the substrate surface, transforming the capacitor layout from planar to立体 (three-dimensional). This allows the chip to maintain a compact form factor while achieving sufficient capacitance through vertical stacking of capacitor layers, effectively decoupling chip area from capacitance requirements.
Solution Approach 2:
The capacitor structures are nested within and above the memory cell structure. The capacitor electrodes and insulating layers are stacked vertically, with lower capacitor layers positioned near the substrate and upper layers extending upward, creating a nested configuration that maximizes capacitance within the vertical space above the memory cells without increasing horizontal footprint.
3Reliability
If capacitor structures are added to increase capacitance, then performance is improved, but device complexity increases
Solution Approach 1:
The manufacturing process merges the formation of memory cell structures and capacitor structures into a unified sequential stacking process. Both structures are formed using the same alternating layers of first and second insulating materials deposited in sequence, eliminating the need for separate fabrication processes. This merging approach increases capacitance while minimizing the addition of process complexity.
Solution Approach 2:
The alternating insulating layer structure serves multiple functions simultaneously: it forms both the capacitor dielectric layers and the isolation structures between memory cells. The same deposited layers provide both capacitive function and structural separation, reducing overall device complexity by making the structure multi-functional rather than requiring separate dedicated components for each function.
Data Source
AI summary
A semiconductor memory device, with which a manufacturing method is associated, includes a substrate. The semiconductor memory device also includes a source structure disposed on a first region of the substrate, memory cell strings connected to the source structure, and a capacitor structure disposed on a second region of the substrate. The capacitor structure is spaced apart from the source structure in a horizontal direction.