Is there any influence of the substrate material on the chucking behavior?

Yes, the substrate material and also the surface in direct contact have a major influence on the electrostatic force. Conductive surfaces have the highest clamping pressure, followed by semi-conductive materials to isolating materials.

The flatter and smoother the surface in direct contact the higher the force, all parts sticking out are acting as spacers which reduce the force. This does not mean that there is not enough fixation force, it is simply reduced compared to the ideal case.