High-Precision Thin Film Thickness Measurement System Based on Pcap01

In the manufacturing industry, there has been an extensive demand for the accurate measurement of material thickness. Hence, this paper presents the design, implementation, and application of a high-precision thickness measurement system based on the Pcap01 chip. The design is based on the principle of capacitive thickness measurement. By placing thin films of different thicknesses between the parallel-plate capacitive probes, the capacitance value of the probes can be changed. The Pcap01 measures the capacitance of the probes based on the Charge-Discharge-Cycle (CDC) principle, and the measurement noise is filtered out through a triple filtering algorithm to stabilize the capacitance measurement data. Furthermore, we deduced from the capacitance value to achieve the measurement value through the standard curve fitting method. In addition, this paper proposed a stable mechanical structure design for the probe device. The experimental results showed that the system could measure the thickness of thin films with high precision in the range of $50-900 \mu \mathrm{~m}$, which has provided an effective design scheme for the thin film thickness measurement system in the industry.