A Linear Non-Contact Measurement of Dielectric Thickness with μm-Resolution

This paper presents a novel system for non-contact thickness measurement of dielectrics with lossless sensitivity. The proposed system incorporates a high-impedance alternating current source and a circular planar capacitance probe to precisely sense dielectric thickness variations. Experimental results demonstrate >99.7% linearity for dielectric samples upto 1000μm thickness, with a sigma variation of 1.2% observed for a 200 μm thick dielectric sample.