problem

The characterization, control and monitoring of plasma processes is crucial for the production of high-quality coatings, surface and material properties. The total energy influx to the substrate (consisting of particle energy, thermal radiation, condensation energy, etc.) is a very important parameter that can only be measured using calorimetric principles so far.

solution

With the active thermal probe, this energy influx can be measured directly in mW/cm², with environmental influences and the heat dissipation to the probe holder being largely compensated.

principle

A specific working temperature of the probe is set by means of a controlled electrical heater and the heating power supplied to maintain thermal equilibrium is measured. The energy influx from the plasma process (e.g. coating) is compensated by changing the heating power, which represents the value of the energy influx.

Sensor                                                 probe shaft                                                                           connector

The energy influx can be measured at selected positions in the system and the correlation with the properties of the layer to be produced or the surface to be treated can be determined. The probe reacts sensitively to changes in the process parameters at the surface of the substrate. The reason for this is that almost all process parameters affect the energy input at the probe.

In one embodiment, the sensor has a metallized surface to which a bias voltage can be applied in order to determine the rate of charged particles in the total energy influx.

advantages

• Easy to install, operate and monitor
• No calibration effort
• Continuous measurement possible
• High sensitivity and accuracy
• Measurement in coating processes possible
• Inexpensive control and monitoring of plasma processes
• Can be used for quality assurance
• Customer-specific adjustments possible
• Suitable for industrial processes and academic issues