Dual RF Matching Control for Stable Plasma Processing
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Solution Overview
Problem
Existing plasma processing systems face instability issues due to overlapping control timings of RF signals, leading to fluctuations in plasma conditions, which can result in lower quality semiconductor substrates.
Innovation Solution
A plasma processing apparatus with a dual RF system and advanced sensor networks that simultaneously and repeatedly acquire multiple parameters associated with RF signals. The system performs sequential and repeated control operations to tune power levels, frequencies, and matching circuit elements based on acquired parameters, ensuring stable plasma maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If simultaneous control of multiple RF signals is implemented, then plasma processing capability is enhanced, but plasma stability deteriorates due to overlapping control timings
Solution Approach 1:
The control operations for multiple RF signals are divided into separate sequential steps rather than being executed simultaneously. The controller performs control operations for each RF signal generator in sequence, with each operation completing before the next begins, thereby preventing overlapping control timings while maintaining the ability to process multiple signals
Solution Approach 2:
The system implements periodic control operations where each RF signal generator undergoes sequential tuning cycles. The controller repeatedly performs control operations in a periodic manner, with each period containing sequential control of individual RF signals, ensuring stable plasma maintenance through rhythmic, non-overlapping adjustment cycles
2Speed
If frequent tuning operations are performed to maintain plasma, then plasma control responsiveness is improved, but plasma stability deteriorates due to excessive changes
Solution Approach 1:
The controller performs tuning operations in periodic cycles rather than continuously or simultaneously. Each periodic cycle includes sequential control of RF signal parameters, allowing the plasma to stabilize between adjustments while maintaining responsive control through repeated cycling
Solution Approach 2:
The controller completes all necessary tuning operations for each RF signal generator before initiating the next control cycle. This preliminary completion of adjustments ensures that full control actions are executed beforehand, preventing intermediate disruptions to plasma stability while maintaining responsive overall control
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 system effectively maintains stable plasma conditions by avoiding overlapping control timings and excessive changes, thereby improving the quality of semiconductor substrates processed using plasma.
Implementation Method 1
a first radio frequency (RF) generator configured to generate a first RF signal having a first frequency
Implementation Method 2
a second RF generator configured to generate a second RF signal having a second frequency
Implementation Method 3
The chamber has a space therein and performs processing on a workpiece carried into the space by plasma generated in the space
Data Source
AI summary
A controller of a plasma processing apparatus is configured to execute (a1) acquiring a first parameter at an input terminal and/or an output terminal of a first matching circuit, (a2) acquiring a second parameter at an input terminal and/or an output terminal of a second matching circuit, and b) performing a first control operation and a second control operation sequentially and repeatedly. The first control operation sequentially performs tuning of a power level of a first RF signal, a frequency of the first RF signal, and a first variable element in the first matching circuit based on the first parameter acquired in the (a1). The second control operation sequentially performs tuning of a power level of a second RF signal, a frequency of the second RF signal, and a second variable element in the second matching circuit based on the second parameter acquired in the (a2).