ESC Monitoring Unit（Capacitance Sensor）
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Connect between the electrostatic chuck (ESC) and the control power supply to monitor the status of the ESC and the workpiece at all times.
ESC Monitoring Unit
- Detect objects via capacitance change
- Identify materials by capacitance value
- Identify topside or bottom side by the difference in capacitance value
- Monitor ESC status constantly
- Capable in detecting capacitance between the ESC and the target workpiece, and monitor process abnormality and its workpiece at all times.
- Add a sensor function without additionally modifying the ESC or its control power supply.
- Digital (2ch) and analog output I/O make it easy to communicate with production equipments
*Minor protrusions are excluded
||Silicon wafer, metal foil, various conductor films
||DC±2.0kV (bipolar ESC)
||0 to 65°C (no condensation)
||Open collector (NPN non-contact type)
||Power supply side: MHV
ESC side: MHV
- Please check our recommended method of use for more information.
- When using this product, please read the instruction manual carefully before use.
- Shall not be used for any purposes other than its intended purpose.
Reference data: Example of loading detection
Capacitive sensors detect changes in the detection electrode (ESC internal electrode) and its vicinity as changes in capacitance. The capacitance of each state obtained by the capacitance detector unit is converted into a voltage signal. By setting the reference voltage and comparing the difference with the detection voltage, it can detect a specific use modes and sudden defects. The following is the result of using a capacitive detection unit to detect each state of the Silicon wafer placed on the ESC.
- Workpiece: Φ300mm silicon wafer
- ESC: Φ300mm ceramic bipolar ESC
- Control power supply: Our ESC control power supply (model number:CTPS-3KV2AF)
- Detection unit: Our inserted capacitance sensor
The capacitance changes in each state are converted into electrical signals as follows:
- (1) Wafer off: The ESC has a silicon wafer and no silicon wafer is set as a reference (0 V).
- (2) Wafer on: A state in which the silicon wafer is placed on the ESC.
- (3) Chucking: A state in which the silicon wafer is gripped by turning on the control power supply.
- (4) Dechucking: The control power supply is turned off.
- (5) Wafer off: A state in which the silicon wafer is removed from the ESC.
- The above detection result is solely an application example and shall be verified by your ESC, control power supply, and workpiece. Please verify the actual connection method and your environment prior to use.
Various materials can be downloaded from here.