Plasma RF Power Control for Low-Reflection Bias Frequency Shifts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Plasma processing apparatuses face challenges in reducing the degree of reflection of radio-frequency power within a waveform period, which affects the efficiency of plasma generation and processing, particularly during processes like etching and cleaning.
Innovation Solution
The apparatus includes a bias power supply that changes the bias frequency of electrical bias energy and a radio-frequency power supply that adjusts the source frequency of the radio-frequency power within the waveform period, reducing the degree of reflection by using multiple frequencies or adjusting voltage levels and duty ratios, thereby optimizing plasma generation and processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the bias frequency is changed during the process, then plasma processing efficiency is improved, but the degree of reflection of radio-frequency power increases
Solution Approach 1:
The patent applies dynamics by making the source frequency adjustable and variable during the plasma processing process. The source frequency is dynamically changed in response to changes in bias frequency, allowing the system to adapt to varying operating conditions while maintaining low reflection levels. This dynamic adjustment resolves the contradiction by enabling both efficient plasma processing and minimal energy loss through real-time frequency optimization.
Solution Approach 2:
The patent utilizes parameter changes by modifying the source frequency parameter in conjunction with bias frequency changes. When the bias frequency is adjusted to improve plasma processing efficiency, the source frequency is simultaneously changed to compensate and minimize reflection. This coordinated parameter adjustment strategy allows the system to achieve improved productivity while preventing increases in energy loss due to reflection.
2Loss of energy
If multiple frequencies are used to reduce reflection, then radio-frequency power utilization is improved, but the device complexity increases
Solution Approach 1:
The patent applies universality by designing a frequency adjustment mechanism that serves multiple functions: it reduces reflection of radio-frequency power, maintains plasma processing efficiency, and adapts to different process conditions. This multi-functional approach allows the system to achieve energy optimization without requiring separate dedicated systems for each function, thereby limiting the increase in device complexity while still utilizing multiple frequencies effectively.
Solution Approach 2:
The patent implements feedback by using a control mechanism that monitors reflection levels and adjusts the source frequency accordingly. When reflection increases due to bias frequency changes, the feedback system automatically modifies the source frequency to minimize reflection. This closed-loop control approach enables effective reflection reduction through multiple frequencies while keeping the device complexity manageable through automated rather than manual adjustment mechanisms.
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 allows for improved plasma processing efficiency by dynamically adjusting frequencies and power levels, enhancing ion energy delivery and reducing damage during etching and facilitating effective cleaning, while minimizing reflection and maintaining process control.
Implementation Method 1
generates source radio-frequency power to generate plasma from a gas within the chamber
Implementation Method 2
bias radio-frequency power is used to introduce ions from plasma generated within a chamber into a substrate
Data Source
AI summary
A plasma processing apparatus includes a chamber, a substrate support, a bias power supply, and a radio-frequency power supply. The bias power supply is electrically coupled to the substrate support and generates electrical bias energy. The radio-frequency power supply is electrically connected to a radio-frequency electrode and generates source radio-frequency power to generate plasma from a gas within the chamber. The bias power supply changes a bias frequency of the electrical bias energy at least once during a process. The radio-frequency power supply changes a source frequency of the source radio-frequency power to reduce a degree of reflection of the source radio-frequency power within a waveform period of the electrical bias energy during the process.