Plasma Ignition Control Through Impedance Matching Path Planning
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Solution Overview
Problem
In plasma processing systems, the simultaneous operation of plasma ignition and impedance matching can lead to unstable plasma ignition, as the matching circuit may be stable only when the plasma is not ignited, and once ignited, the plasma can be extinguished due to the matching operation.
Innovation Solution
A plasma processing system with a control device that collects measurement values of impedance matching between the power supply and plasma, specifies control variables to maximize the gradient of light emission intensity, and controls these variables to steer the plasma ignition process along a straight line from a starting point to a matching point, ensuring stable ignition by adjusting the capacitance values in the matcher circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the matching circuit is stabilized during plasma ignition, then power supply efficiency improves, but plasma extinguishment risk increases
Solution Approach 1:
The patent performs impedance matching as a preliminary action before plasma ignition. By specifying a starting point for matching that ensures circuit stabilization without interfering with plasma generation, the system achieves efficient power supply while maintaining plasma stability. The control device manages the timing and parameters of impedance matching to prevent plasma extinguishment.
2Power
If impedance matching is optimized after plasma ignition, then power transfer efficiency increases, but the plasma state becomes unstable
Solution Approach 1:
The patent optimizes impedance matching as a preliminary action before plasma ignition rather than after. The control device specifies appropriate starting and ending points for the matching process, ensuring that the matching circuit is optimized in advance. This approach achieves high power transfer efficiency while maintaining plasma state stability, as the matching optimization does not interfere with the already-stabilized plasma.
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 the stable ignition and maintenance of plasma, reducing the risk of plasma extinguishment and improving the efficiency of radio-frequency power supply to the plasma, thereby enhancing the plasma processing stability.
Implementation Method 1
a radio-frequency power is supplied into the processing container to convert the processing gas into a plasma
Implementation Method 2
adjusting a capacitance value of each capacitor included in the matcher circuit
Data Source
AI summary
A plasma processing system includes a plasma processing apparatus including a processing container that accommodates a substrate, and configured to perform a plasma processing on the substrate by generating a plasma in the processing container; and a control device configured to control the plasma processing apparatus. The control device collects a measurement value indicating a matching state of impedance between a power supply and the plasma; specifies a point corresponding to a value of the variables that maximizes a gradient of change of the measurement value with respect to a vector; specifies a point farther from the matching point than the passing point on a straight line; and ignites the plasma in the plasma processing apparatus by controlling each variable so that the measurement value changes from the starting point toward the matching point along the straight line.