Bias Power Supply Waveforms for Real-Time Ion Energy Control
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Solution Overview
Problem
Existing plasma processing systems lack non-invasive and real-time means for monitoring ion energy and ion energy distribution function (IEDF), hampering precise control over ion energy during processing.
Innovation Solution
A bias supply configured to provide a modified periodic voltage function, utilizing a switch-mode power supply with controlled timing of drive signals to generate desired ion energy distributions, and an ion current compensation component to maintain ion energy distribution width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional plasma processing systems are used, then plasma density can be maintained, but ion energy and IEDF cannot be precisely controlled or monitored in real-time
Solution Approach 1:
The patent introduces an intermediary measurement technique that derives ion energy and IEDF information from existing electrical parameters (voltage and current waveforms) rather than requiring direct physical measurement probes in the plasma. This intermediary approach allows precise ion energy monitoring through electrical signals that can be obtained without disrupting the plasma environment.
Solution Approach 2:
The patent replaces complex mechanical or physical measurement systems with electrical measurement and calculation methods. Instead of using physical probes that would complicate the system, the invention uses electrical voltage and current waveform analysis to determine ion energy parameters, thereby reducing device complexity while maintaining measurement precision.
2Manufacturing precision
If ion energy control is improved, then processing precision increases, but energy consumption increases
Solution Approach 1:
The patent implements periodic pulsing of the plasma source and bias supply, allowing the system to achieve precise ion energy control during active pulses while reducing overall energy consumption during off periods. This periodic operation enables high manufacturing precision when needed while minimizing average energy usage across the complete duty cycle.
Solution Approach 2:
The patent uses dynamic adjustment of bias voltage waveforms to optimize ion energy delivery. By dynamically modulating the bias supply in real-time based on process requirements, the system achieves precise ion energy control only when necessary, rather than maintaining constant high-energy states, thereby reducing overall energy consumption while maintaining manufacturing precision.
3Extent of automation
If real-time monitoring of plasma parameters is implemented, then process control improves, but system complexity increases
Solution Approach 1:
The patent makes the existing electrical measurement system multi-functional by using the same voltage and current sensors to derive multiple plasma parameters simultaneously (ion energy, IEDF, plasma density indicators). This universal approach enables real-time monitoring of multiple parameters without adding separate dedicated measurement systems for each parameter, thereby improving automation extent while limiting complexity growth.
Solution Approach 2:
The patent enables the plasma processing system to self-monitor its own parameters by analyzing its existing operational electrical signals. The system uses its own voltage and current waveforms during normal operation to derive ion energy and IEDF information, eliminating the need for separate external monitoring equipment and reducing overall system complexity while achieving real-time automation.
Data Source
AI summary
This disclosure describes systems, methods, and apparatus for controlling ion energy in a plasma processing chamber. In particular, a system for plasma processing includes a plasma processing chamber, a plasma source coupled to the plasma processing chamber, a plasma power supply coupled to the plasma source that is configured to apply power to the plasma processing chamber in periodic pulse envelopes to control a density of a plasma in the plasma processing chamber, and a support within the plasma processing chamber to support a substrate. A bias supply is configured to provide a modified periodic voltage function to the substrate support within each of the periodic pulse envelopes to control an energy of ions impacting the substrate support in the plasma processing chamber.