Plasma Processing Device Maintenance Detection via Discharge Waveforms
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Solution Overview
Problem
Conventional plasma processing devices face challenges in accurately determining the maintenance time due to the deposition of foreign objects, which can lead to unstable plasma discharge and prolonged vacuum exhaustion times, making it difficult to maintain optimal operating conditions.
Innovation Solution
A plasma processing device equipped with a plasma discharge state monitoring unit that includes a discharge detection sensor with a plate-shaped dielectric member and a probe electrode, capable of detecting specific electric potential change waveforms indicative of abnormal and leak discharges, allowing for accurate counting and judgment of maintenance needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If vacuum exhausting time is measured to determine maintenance timing, then the method is simple to implement, but it cannot accurately detect foreign object deposition until a considerable quantity accumulates
Solution Approach 1:
The patent replaces the mechanical/vacuum-based measurement method with an electromagnetic field-based detection system. A sensor detects plasma discharge characteristics through electromagnetic signals, substituting the vacuum exhaustion time measurement method with a more sensitive electrical detection method that can identify foreign object deposition at earlier stages.
Solution Approach 2:
The patent introduces plasma discharge characteristics as an intermediary indicator to detect foreign object deposition. Instead of directly measuring foreign objects or vacuum time, the system uses plasma discharge parameter changes (caused by foreign objects) as a mediator to infer deposition status, enabling earlier and more accurate detection.
2Productivity
If foreign objects are allowed to accumulate before maintenance, then the device can operate longer without interruption, but the plasma discharge becomes unstable and vacuum exhaustion time increases
Solution Approach 1:
The patent implements a feedback mechanism where plasma discharge characteristics are continuously monitored and fed back to determine maintenance timing. When foreign object deposition reaches a threshold that affects plasma discharge, the system automatically triggers maintenance, creating a closed-loop control that maintains plasma stability while maximizing operational time.
Solution Approach 2:
The patent performs preliminary detection of foreign object deposition by monitoring plasma discharge characteristics before significant accumulation occurs. This preliminary action allows maintenance to be scheduled proactively based on actual deposition conditions rather than fixed time intervals, optimizing both productivity and reliability.
3Reliability
If the vacuum chamber is opened and closed frequently for maintenance, then foreign object deposition can be removed timely, but the vacuum exhausting time increases due to absorbed vapor and gases
Solution Approach 1:
The patent uses real-time monitoring of plasma discharge characteristics to provide feedback on foreign object deposition status. This enables maintenance to be performed only when necessary, avoiding unnecessary vacuum chamber openings and closings, thus reducing the time loss from repeated vacuum exhaustion cycles while maintaining plasma discharge stability.
Solution Approach 2:
The patent changes the monitoring parameter from vacuum exhaustion time to plasma discharge characteristics. This parameter change allows detection of foreign object deposition without requiring vacuum chamber opening, eliminating the time loss associated with frequent vacuum cycles while maintaining reliable detection capability.
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 determination of the necessary maintenance time, ensuring the device operates in optimal conditions by sensitively detecting minute changes in plasma discharge patterns, thereby improving the accuracy of maintenance scheduling.
Implementation Method 1
a first wave-form detecting portion for receiving a change in electric potential induced according to a change in the plasma discharge in the probe electrode
Data Source
AI summary
An object is to provide a plasma processing device capable of accurately judging whether or not the proper maintenance time has come which is necessary for maintaining an operation state of a device in the best condition.A discharge detection sensor 23, in which a dielectric member 21 and a probe electrode unit 22 are combined with each other, is attached to an opening portion 2a provided in a lid portion 2 composing a vacuum chamber. A change in the electric potential induced in the probe electrode 22b according to a change in plasma discharge is received and whether or not the maintenance work is necessary is judged by comparing a counted value, which is obtained when a leak discharge wave-form counter 39 counts the number of times of the detection of detecting a V-type wave form of a V-shaped specific pattern, which is caused by leak discharge correlated with the attachment of foreign object in the vacuum chamber, by a V-type wave-form detecting portion 35, with an allowable value which has been previously set by a maintenance judging portion 44.