Capacitive thickness measurements in high precision applications


On the one hand, capacitive sensors from Micro-Epsilon measure displacement and distance on a non-contact basis, but on the other hand are used for non-contact thickness measurements. capaNCDT sensors achieve best values, e.g., in terms of linearity, repeatability and resolution and achieve submicron accuracy in industrial environments. Due to their incredibly high temperature stability, they generate stable measurement values even in fluctuating ambient temperatures.

Each capacitive sensor can be operated with any Micro-Epsilon controller without requiring any complex calibration. Various interfaces such as analog, Ethernet and EtherCAT enable connection to modern machines and systems. Settings can be made via the user-friendly web interface.

In production monitoring, for example, capacitive sensors measure film thickness and application of the adhesive. Installed in machines, they monitor displacement and tool positions.

High precision thickness measurements of battery films

In order to determine the thickness of battery films with high accuracy, capacitive sensors are used directly in the production line. For this purpose, the sensors are attached to a measuring bracket and measure onto the film from two sides. Each of the two capacitive displacement sensors delivers a high-resolution distance signal, which is directly processed in the DT6200 controller as a thickness measurement value. Since the measurement spot of the sensors is larger than with optical measuring methods, structures and anomalies on the surface are averaged. Due to their high temperature stability, the sensors provide stable measurement values even with fluctuating ambient temperatures.

For precise thickness measurements, the innovative capaNCDT 6200 multi-channel controller is used. It detects, processes and evaluates values from up to four channels simultaneously. For fast measurements up to 20 kHz, the capaNCDT 6222 multi-channel system is used.

High precision thickness measurement of silicon wafers

Capacitive displacement sensors are used for exact thickness measurement of wafers. Two opposing sensors detect the thickness. They detect even parameters such as bows. The position of the wafer in the measuring gap may vary without influencing the measurement accuracy.

If the installation space is limited, you can use capacitive flat sensors. The smallest available height is just 4 mm.


Advantages of capacitive sensors

  •  Highest precision with subnanometer accuracy
  • Excellent temperature stability
  • Very high application versatility: semiconductor industry, air gap measurement of large motors, deformation measurement of brake discs, positioning of machines
  • Ease of use via web interface
  • Modular & syncable multi-channel controllers

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