Focus Ring Consumption Measurement via Capacitance Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In plasma processing apparatuses, the focus ring surrounding the target object is consumed during processing, affecting the uniformity of processing and necessitating regular inspection and replacement, but existing methods lack efficient means to quantify this consumption accurately.
Innovation Solution
A measuring device comprising a disc-shaped base substrate with sensor electrodes and a high-frequency oscillator, which calculates electrostatic capacitances to determine the consumption of the focus ring by transferring to a central position and referencing a consumption table.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the focus ring is used continuously in plasma processing, then productivity is improved, but the focus ring is consumed and processing uniformity deteriorates
Solution Approach 1:
The patent implements periodic inspection of the focus ring before it reaches excessive consumption levels. The measuring device is positioned to contact the focus ring during processing cycles, performing preliminary measurements that allow timely replacement before processing uniformity deteriorates, thus maintaining both productivity and reliability
Solution Approach 2:
The patent establishes a feedback mechanism where measurement results from the sensor electrode are fed back to determine whether the focus ring should be replaced. The measuring device provides continuous or periodic feedback on the focus ring's wear state, enabling dynamic adjustment of processing operations to maintain processing uniformity while maximizing productivity
2Reliability
If the focus ring is replaced frequently to maintain processing uniformity, then reliability is improved, but productivity deteriorates due to downtime
Solution Approach 1:
The measuring device performs preliminary inspection of the focus ring during processing cycles, identifying wear issues before they critically affect processing uniformity. This allows planned replacement at optimal moments rather than emergency replacement that disrupts productivity, thus resolving the contradiction between maintaining reliability and preserving productivity
Solution Approach 2:
The measuring device is integrated into the processing system itself, allowing the focus ring inspection to be performed automatically during normal operations without requiring separate inspection procedures or additional downtime. The system essentially inspects itself, maintaining reliability monitoring while minimizing impact on productivity
3Measurement precision
If a measuring device is added to inspect the focus ring, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent introduces a sensor electrode as an intermediary element that indirectly measures focus ring consumption through capacitance changes. Instead of directly measuring physical wear dimensions, the intermediary electrical measurement provides precise consumption data through changes in capacitive coupling between the sensor electrode and the focus ring, achieving high measurement precision while avoiding complex direct measurement mechanisms
Solution Approach 2:
The patent replaces potential mechanical measurement approaches with an electrical field-based measurement system. The sensor electrode uses electrical capacitance changes to detect focus ring consumption, substituting mechanical contact or optical measurement systems with a simpler electrical field interaction that achieves precise measurement with minimal device complexity
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 precise measurement and timely replacement of the focus ring, ensuring consistent processing quality and extending its operational life.
Implementation Method 1
the operation unit calculates a plurality of measurement values indicating electrostatic capacitances of the plurality of sensor electrodes from a plurality of detection values corresponding to potentials of the plurality of sensor electrodes
Data Source
AI summary
A measuring device and method, provided in a region surrounded by a focus ring and configured to measure an amount of consumption of the focus ring, includes a disc-shaped base substrate, sensor electrodes provided on the base substrate, a high frequency oscillator configured to apply a high frequency signal to the sensor electrodes, and an operation unit configured to calculate measurement values indicating electrostatic capacitances of the sensor electrodes from detection values corresponding to potentials of the sensor electrodes. The operation unit calculates a representative value (for example an average value) of the measurement values corresponding to the amount of consumption of the focus ring and derives the amount of consumption of the focus ring with reference to a table in which the amount of consumption of the focus ring is associated with the representative value of the measurement values.