Plasma Top Plate Thickness Calculation via Heater Power
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Solution Overview
Problem
In plasma processing apparatuses, determining the degree of top plate consumption is challenging, leading to fluctuations in etching characteristics and uniformity, which reduces productivity due to the need for conservative replacement times based on past results rather than actual consumption levels.
Innovation Solution
The apparatus includes a support with a detachable top plate and a heater controller that measures and adjusts temperature, using a parameter calculator to calculate the top plate thickness by fitting a calculation model with measured supply power in non-ignition and transient states, allowing for precise determination of top plate consumption without direct thickness measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conservative replacement times based on past results are used, then reliability of etching characteristics is maintained, but productivity decreases due to unnecessary early replacements
Solution Approach 1:
The patent replaces direct mechanical thickness measurement with an electrical measurement system. By measuring supply power changes in the heater during plasma ignition and transient states, the system indirectly determines top plate thickness without physical contact or direct measurement, thus maintaining reliability while improving productivity
Solution Approach 2:
The patent introduces supply power measurement as an intermediary parameter to determine top plate thickness. Instead of directly measuring thickness, the system measures the electrical power consumed by the heater, which changes predictably with top plate thickness, providing an indirect but accurate measurement method
2Measurement precision
If direct thickness measurement methods are used, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent makes the existing heater serve multiple functions: it not only heats the top plate for plasma generation but also acts as a measurement sensor for thickness determination. By measuring the supply power to this multi-functional heater, the system achieves thickness measurement without adding separate measurement devices, thus improving precision while minimizing complexity increase
Solution Approach 2:
The heater automatically provides measurement information through its own operating characteristics. The change in supply power required to maintain constant heater temperature directly indicates top plate thickness, allowing the system to self-diagnose without external measurement equipment
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 timely and accurate determination of top plate consumption, improving productivity by allowing for optimized maintenance schedules and reducing the need for conservative replacement times, thus enhancing the overall efficiency of the plasma processing system.
Implementation Method 1
a heater capable of adjusting the temperature of a support surface of the top plate
Implementation Method 2
measure a supply power in a non-ignition state where the plasma is not ignited and in a transient state where the supply power to the heater is reduced after the plasma is ignited
Data Source
AI summary
A plasma processing apparatus includes a measurement unit that, while controlling a supply power to a heater such that a temperature of the heater becomes constant, measures the supply power to the heater in a non-ignition state where a plasma is not ignited and in a transient state where the supply power to the heater is reduced after the plasma is ignited. The plasma processing apparatus also includes a parameter calculator that calculates a thickness of a top plate by performing a fitting on a calculation model which includes the thickness of the top plate as a parameter and calculates the supply power in the transient state, using the measured supply power in the non-ignition state and the transition state.