Cylindrical Capacitor Support Structure for Leaning Prevention
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Solution Overview
Problem
Conventional cylindrical capacitors in semiconductor devices face issues such as high aspect ratio leading to adjacent capacitors leaning on each other, difficulty in forming a uniform dielectric layer, and the need for multiple processes to form the lower electrode, resulting in reduced capacitance and increased risk of 2-bit failures.
Innovation Solution
Incorporating a support structure within the cylindrical lower electrode structure, formed by sequential layers of a filler and etch stop layers, which allows for the formation of a dielectric layer on both electrodes and prevents adjacent capacitors from leaning, while maintaining high capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lower electrode height is increased to achieve high capacitance, then capacitance is improved, but the lower electrode cannot be formed by a single process
Solution Approach 1:
The lower electrode formation process is segmented into multiple steps: first forming a first lower electrode, then adding a second lower electrode on top. This segmentation allows each electrode segment to be formed within a manageable height range that can be achieved by standard deposition processes, making the manufacturing feasible while maintaining the total height needed for high capacitance
Solution Approach 2:
The first lower electrode is formed in advance before the second lower electrode is added. This preliminary action establishes a foundation that enables subsequent processing steps, including the formation of the support structure and the addition of the second electrode segment, making the overall high-height electrode formation manufacturable
2Reliability
If the dielectric layer thickness is increased to achieve high capacitance, then capacitance is improved, but the dielectric layer cannot be formed uniformly on the lower electrode
Solution Approach 1:
By segmenting the lower electrode into multiple smaller segments separated by the support structure, the vertical distance (height) that the dielectric layer must conformally coat is reduced. This segmentation enables uniform dielectric layer formation through standard deposition processes, as each segment's height is within the achievable range for uniform coating, while the overall capacitance is maintained through the combined effect of multiple segments
Data Source
AI summary
A method of forming a capacitor includes forming a cylindrical lower electrode structure having an internal support structure on a substrate, forming a dielectric layer on the cylindrical lower electrode structure and the support structure, and forming an upper electrode on the dielectric layer.