Heater Power-Based Plasma State Detection Without In-Chamber Sensors
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Solution Overview
Problem
Existing plasma processing apparatuses face challenges in detecting plasma states without disrupting the plasma environment, as sensors can alter plasma characteristics and lead to non-uniform processing and potential abnormalities.
Innovation Solution
A plasma processing apparatus that includes a stage with heaters, a heater controller, a measurement part, and a parameter calculator, which calculates the heat input amount from plasma by analyzing power supplied in unignited and ignited states, allowing for plasma state detection without sensors in the processing container.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensors are arranged in the processing container to detect plasma state, then plasma state detection capability is improved, but plasma environment is disrupted and measurement precision deteriorates
Solution Approach 1:
The patent uses the heater as an intermediary element to detect plasma state. Instead of placing sensors directly in the plasma environment, the heater's power consumption serves as a indirect indicator of plasma conditions. The controller monitors the power supplied to the heater, which changes in response to plasma state, thereby detecting plasma characteristics without physical sensor intrusion.
Solution Approach 2:
The patent replaces the traditional mechanical/electrical sensor system with a thermal-based detection method. By measuring the electrical power consumed by the heater (which is thermally coupled to the plasma environment), the system substitutes direct electrical sensing with indirect thermal measurement, avoiding sensor interference while maintaining detection capability.
2Loss of information
If sensors are disposed in the processing container to detect plasma, then plasma state information is obtained, but device complexity increases and reliability decreases
Solution Approach 1:
The heater serves multiple functions: it provides thermal control for the substrate and simultaneously acts as a plasma state detection element. By making the heater multi-functional, the patent eliminates the need for separate sensors, thereby reducing device complexity while maintaining plasma state information capability.
Solution Approach 2:
The heater performs self-detection by having its power consumption automatically monitored and analyzed by the controller. The system uses its own operational parameter (power consumption) as the detection signal, eliminating the need for external sensing infrastructure and reducing overall system complexity.
3Productivity
If sensors are placed in the processing container to detect plasma, then real-time plasma monitoring is achieved, but manufacturing precision deteriorates due to non-uniform processing
Solution Approach 1:
The heater acts as a remote intermediary detection point that reflects plasma state without being directly exposed to it. This indirect measurement approach provides real-time plasma monitoring information while avoiding the disruption and non-uniformity caused by physical sensors in the plasma environment.
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
Enables accurate detection of plasma states and density distribution without sensor interference, ensuring consistent and reliable plasma processing without affecting the plasma environment.
Implementation Method 1
a heater configured to adjust a temperature of a mounting surface on which a workpiece as an object to be plasma-processed is placed
Implementation Method 2
perform fitting on a calculation model, which includes a heat input amount from the plasma as a parameter
Data Source
AI summary
A measurement part controls power supplied to a heater such that a temperature of the heater becomes constant by using a heater controller, and measures the supplied power in an unignited state in which plasma is not ignited and a transient state in which the power supplied to the heater decreases after plasma is ignited. A parameter calculator performs fitting on a calculation model, which includes a heat input amount from the plasma as a parameter, for calculating the power supplied in the transient state by using the power supplied in the unignited state and the transient state and measured by the measurement part, and calculates the heat input amount. An output part configured to output information based on the heat input amount calculated by the parameter calculator