Plasma Heater Power Fitting for Consumable Thickness Monitoring
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Solution Overview
Problem
In plasma processing apparatuses, the consumption of consumable parts like focus rings leads to deteriorating etching characteristics on semiconductor wafers, necessitating periodic replacement, which is inefficient and reduces productivity due to the need for margin in replacement timing and monitoring processes.
Innovation Solution
A plasma processing apparatus with a mounting table and control unit that measures and adjusts heater power to maintain constant temperature, allowing for calculation of consumable part thickness and optimal power usage, thereby determining the precise replacement time of consumable parts without direct measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If consumable parts are replaced periodically based on monitoring, then etching quality is maintained, but productivity decreases due to replacement downtime and monitoring overhead
Solution Approach 1:
The consumable part itself serves as the sensor by utilizing its inherent electrical properties (resistance, capacitance, or impedance changes) to indicate its own thickness and consumption state, eliminating the need for external monitoring systems and enabling autonomous condition assessment
Solution Approach 2:
The patent replaces mechanical measurement methods (such as physical thickness measurement or visual inspection) with electrical measurement methods by applying voltage or current to the consumable part and detecting changes in electrical properties that correlate with thickness reduction
2Measurement precision
If additional sensors are installed to monitor consumable part thickness, then replacement timing accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The consumable part itself serves as the sensor by utilizing its inherent electrical properties (resistance, capacitance, or impedance changes) to indicate its own thickness and consumption state, eliminating the need for external monitoring systems and enabling autonomous condition assessment
Solution Approach 2:
The consumable part performs dual functions: it serves both as the functional component (focus ring, electrostatic chuck, or coil) and as the sensing element for monitoring its own consumption state, eliminating the need for separate dedicated sensors
3Reliability
If consumable parts are replaced with margin timing, then etching quality is ensured, but time is lost due to premature replacement
Solution Approach 1:
The system continuously monitors the electrical properties of the consumable part and provides real-time feedback on its consumption state, enabling dynamic adjustment of replacement timing based on actual condition rather than fixed schedules, thus optimizing the balance between quality assurance and time efficiency
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 enables accurate determination of consumable part consumption, improving productivity by allowing for timely replacement and maintaining consistent etching quality without the need for additional sensors, thus enhancing the overall efficiency of the plasma processing system.
Implementation Method 1
a heater configured to adjust a temperature of a mounting surface on which a consumable part that is consumed by plasma processing is mounted
Data Source
AI summary
In a plasma processing apparatus, a mounting table includes a heater for adjusting a temperature of a mounting surface mounting thereon a consumable part consumed by plasma processing. A heater control unit controls a supply power to the heater such that the heater reaches a setting temperature. A measurement unit measures, while controlling the supply power to the heater such that the temperature of the heater becomes constant, the supply powers in a non-ignition state where plasma is not ignited and in a transient state where the supply power is decreased after the plasma is ignited. A parameter calculation unit calculates a thickness of the consumable part by performing fitting with a calculation model, which has the thickness of the consumable part as a parameter and calculates the supply power in the transient state, by using the measured supply powers in the non-ignition state and in the transient state.