How does electrostatic fixation work?

There are two principles generating electrostatic forces, the so called Johnsen-Rahbek effect and the Coulomb force. Both types rely on high voltage applied to one or more electrodes. However, the force generation mechanism is different. In Johnsen-Rahbek chucks a current runs through the dielectric and leads to strong forces in direct contact with the substrate material.

The Coulomb chuck is usually using a higher voltage but with only a small chucking current it is acting like a plate capacitor where the electrical field between both plates is pushing them together. Therefore, no direct contact between chuck and substrate is needed, but the closer the chuck is to the substrate surface the higher is the force.