Focus Ring Inspection via Electrostatic Capacitance Scanning
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Solution Overview
Problem
In plasma processing apparatuses, the focus ring is consumed during the processing of objects, leading to uneven processing and the need for frequent replacement, necessitating a method to accurately assess its consumption levels.
Innovation Solution
A system and method utilizing a measuring device with sensor chips and a circuit board to measure electrostatic capacitance, which calculates consumption amounts by scanning the focus ring and obtaining difference values across its periphery, allowing for precise determination of wear levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the focus ring is used for plasma processing, then processing capability is maintained, but the focus ring is consumed and requires replacement
Solution Approach 1:
The system performs preliminary inspection of the focus ring by measuring electrostatic capacitance at multiple positions before the focus ring is excessively consumed. This allows determining the replacement timing in advance, preventing processing quality degradation while optimizing the usage lifecycle of the focus ring.
2Reliability
If the focus ring is inspected frequently to determine replacement timing, then processing uniformity is maintained, but inspection time and complexity increase
Solution Approach 1:
The system replaces complex mechanical measurement methods with electrostatic capacitance measurement. By measuring the electrostatic capacitance between the focus ring and a sensor electrode, the system可以快速 determine the thickness or consumption of the focus ring without physical contact or complex mechanical scanning, significantly reducing inspection time while maintaining accuracy.
3Measurement precision
If electrostatic capacitance measurement is used to inspect the focus ring, then consumption amount is accurately determined, but measurement system complexity increases
Solution Approach 1:
The system introduces an intermediary electrode positioned between the focus ring and the measurement system. This intermediary electrode facilitates the electrostatic capacitance measurement by creating a controlled measurement field, allowing accurate determination of focus ring consumption without requiring direct contact or complex positioning mechanisms.
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 assessment of focus ring consumption, facilitating timely replacement and maintaining processing uniformity, thereby improving the efficiency and effectiveness of plasma processing operations.
Implementation Method 1
The circuit board is configured to output a high frequency signal to the sensor electrode and acquire a digital value indicating electrostatic capacitance based on a voltage amplitude in the sensor electrode
Data Source
AI summary
A system of inspecting a focus ring is provided. The system includes a measuring device, a transfer device and an operation unit. The measuring device includes a base substrate, a sensor chip and a circuit board. The sensor chip has a sensor electrode and is provided along an edge of the base substrate. The circuit board is configured to output a high frequency signal to the sensor electrode and acquire a digital value indicating electrostatic capacitance based on a voltage amplitude in the sensor electrode. The transfer device is configured to scan the measuring device. The operation unit is configured to obtain difference values by performing a difference operation with respect to the digital values acquired by the measuring device at multiple positions along a direction which intersects with an inner periphery of the focus ring.