Non-Sinusoidal RF Signal Ion Energy Control
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Solution Overview
Problem
Existing plasma processing systems face challenges in effectively controlling ion energy distribution, leading to issues such as etch selectivity, faceting, and profile control in high aspect-ratio contacts, and require external DC blocking capacitors and complex insulation designs.
Innovation Solution
A plasma processing system that uses a non-sinusoidal RF signal provided to a non-substrate bearing electrode, eliminating the need for external DC blocking capacitors and minimizing design restrictions, allowing for improved control of ion energy distribution with reduced parasitic capacitance and increased efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an external DC blocking capacitor is used between the RF signal source and the substrate-bearing electrode, then ion energy distribution can be controlled, but the device complexity increases and parasitic capacitance increases
Solution Approach 1:
The patent extracts the DC blocking function from an external capacitor and integrates it into the electrode structure itself. The substrate-bearing electrode is designed with an inherent series capacitance that provides the necessary DC blocking while eliminating the need for separate external capacitors, thereby reducing device complexity and parasitic capacitance.
Solution Approach 2:
The substrate-bearing electrode is given multiple functions: it serves as both the substrate support and the DC blocking element. By integrating the capacitance function into the electrode itself, the system eliminates separate components while maintaining the necessary electrical isolation between the RF signal source and substrate.
2Manufacturing precision
If an external DC blocking capacitor is used to control ion energy distribution, then ion energy control is achieved, but the size of RF components increases
Solution Approach 1:
The patent merges the DC blocking capacitor function with the substrate-bearing electrode structure. Instead of having separate external capacitors, the electrode itself is designed to provide the necessary capacitance, thereby reducing the overall size of RF components while maintaining ion energy distribution control.
3Reliability
If complex insulation designs are used in plasma processing systems, then electrical isolation is achieved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent extracts the DC blocking function from external insulation components and integrates it directly into the electrode structure. This eliminates the need for complex external insulation designs while maintaining reliable electrical isolation, thereby simplifying manufacturing.
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
This approach enhances the accuracy and cost-effectiveness of ion energy distribution control, reducing the size of RF components and improving response times, while maintaining high voltage sheaths and ion energy delivery to the substrate.
Implementation Method 1
This non-sinusoidal signal may control the ion energy distribution, for example, by attracting ions
Data Source
AI summary
A plasma processing system for processing at least a substrate with plasma. The plasma processing chamber is capable of controlling ion energy distribution. The plasma processing system may include a first electrode. The plasma processing system also includes a second electrode that is different from the first electrode and is configured for bearing the substrate. The plasma processing system may also include a signal source coupled with the first electrode. The signal source may provide a non-sinusoidal signal through the first electrode to control ion energy distribution at the substrate when the substrate is processed in the plasma processing system, wherein the non-sinusoidal signal is periodic.