Lower Electrode Supporters for DRAM Capacitor Bowing
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Solution Overview
Problem
Current semiconductor technologies face challenges in increasing capacitance within a limited area of dynamic random access memory (DRAM) devices, particularly in maintaining the structural integrity and reducing bowing of lower electrodes in high-integration semiconductor devices.
Innovation Solution
A semiconductor device is fabricated with a double supporter structure using carbon-based materials like SiCN and SiN, positioned between lower electrodes to suppress bowing and enhance structural stability, and a method involving sequential formation of mold oxide films and supporters with specific etch selectivity and gas usage to achieve this configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the effective area of lower electrode is increased to enhance capacitance, then the capacitance increases, but the structural integrity and stability of the lower electrode deteriorates due to bowing
Solution Approach 1:
A supporter layer is introduced as an intermediary component between the lower electrode and the dielectric film. This supporter acts as a mediator that provides mechanical support to the lower electrode, preventing bowing while allowing the electrode to maintain a larger effective area for enhanced capacitance.
Solution Approach 2:
The supporter is formed using composite materials with specific properties - it has etch selectivity relative to both the lower electrode and mold oxide film, and exhibits appropriate mechanical properties to suppress bowing. The composite nature of the supporter material enables it to fulfill multiple functions simultaneously.
2Stability of the object's composition
If a supporter structure is added to suppress bowing of lower electrodes, then the structural stability improves, but the device complexity increases
Solution Approach 1:
The capacitor structure is segmented into distinct functional layers: the lower electrode, the supporter layer, and the dielectric film. Each layer has a specific function, and the supporter is positioned between the other two components. This segmentation allows for independent optimization of each component while maintaining overall structural stability.
Solution Approach 2:
The supporter layer serves multiple functions: it provides mechanical support to prevent bowing, acts as an etch stop layer during fabrication, and maintains the structural integrity throughout the device. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity.
3Manufacturing precision
If multiple materials are used for the supporter to achieve etch selectivity, then the manufacturing precision improves, but the ease of manufacture decreases
Solution Approach 1:
The supporter is formed by changing material parameters - specifically, by selecting materials with appropriate etch rates relative to the lower electrode and mold oxide film. The supporter material exhibits etch selectivity that enables precise formation of the lower electrode through selective etching processes, achieving high manufacturing precision.
Data Source
AI summary
A semiconductor device and a method of fabricating the same, the device including a substrate having a transistor formed thereon; a plurality of lower electrodes formed on the substrate; a first supporter and a second supporter on the plurality of lower electrodes; a dielectric film formed on the lower electrode, the first supporter, and the second supporter; and an upper electrode formed on the dielectric film, wherein the first and second supporters are positioned between the lower electrodes, and the first and second supporters include a first material and a second material.