Multi-Layered Capacitor Bottom Electrode Structural Integrity
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Solution Overview
Problem
The conventional hollow semicrown-shaped bottom electrode in semiconductor capacitors lacks sufficient mechanical supporting strength, leading to potential leaning or collapse during fabrication processes as the lateral width is reduced to increase capacitance.
Innovation Solution
A multi-layered bottom electrode is created using a conductive pillar and an electroplating structure, where the conductive pillar and electroplating layers provide enhanced mechanical support through deposition and electrochemical plating techniques, with materials like titanium nitride and ruthenium or platinum used for the conductive and electroplating layers respectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lateral width of the capacitor is reduced to increase capacitance, then the capacitance increases, but the mechanical supporting strength decreases leading to potential leaning or collapse
Solution Approach 1:
The bottom electrode is constructed as a multi-layered composite structure combining a conductive pillar material (titanium nitride or tantalum nitride) with an electroplated material (ruthenium or platinum). This composite structure provides both the required capacitance through increased surface area and sufficient mechanical strength through the combined properties of the different materials, resolving the contradiction between reduced lateral width and maintained structural integrity.
2Reliability
If the aspect ratio of the capacitor is increased to maintain or increase capacitance, then the capacitance is maintained, but the mechanical stability deteriorates causing the bottom electrode to lean or collapse
Solution Approach 1:
The multi-layered bottom electrode combining conductive pillar material with electroplated material provides enhanced mechanical stability while maintaining the high aspect ratio needed for sufficient capacitance. The composite structure distributes mechanical stresses more effectively than a single-material structure, preventing leaning or collapse during fabrication processes.
3Reliability
If a hollow semicrown-shaped bottom electrode is used to increase surface area, then the capacitance increases, but the mechanical supporting strength is insufficient
Solution Approach 1:
The hollow semicrown-shaped bottom electrode is constructed using composite materials - a conductive pillar core made of titanium nitride or tantalum nitride, and an outer electroplated layer of ruthenium or platinum. This composite construction maintains the high surface area needed for capacitance while the combined material structure provides the mechanical strength that a single-material hollow structure cannot achieve.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The multi-layered bottom electrode structure effectively prevents the capacitor from leaning or collapsing during fabrication, maintaining structural integrity and capacitance by providing sufficient mechanical support.
Implementation Method 1
performing a first electrochemical plating process to form a first conductive layer on an inner surface of the conductive pillar, removing a portion of the stacked structure and performing a second electrochemical plating process to form a second conductive layer covering an outer surface of the conductive pillar
Implementation Method 2
uses the deposition technique and the electroplating technique to prepare a multi-layered bottom electrode
Data Source
AI summary
A capacitor structure comprises a substrate having a contact plug, a conductive cylinder positioned on the substrate and an electroplating structure covering the conductive cylinder, wherein a bottom electrode of the capacitor structure comprises the conductive cylinder and the electroplating structure. The conductive cylinder can be a hollow conductive cylinder, and the electroplating structure comprises a first conductive layer covering the inner sidewall and bottom surface of the hollow conductive cylinder and a second conductive layer covering the first conductive layer and the outer sidewall of the hollow conductive cylinder. The conductive cylinder and the electroplating structure can be made of different conductive material, and the free end of the conductive cylinder is preferably round. The conductive cylinder can be made of titanium nitride or tantalum nitride, while the electroplating structure can be made of ruthenium or platinum.