New Parylene Coating System with Real-Time and Non-Destructive Electrical Impedance Monitoring of Parylene Layer.

Parylene is one of the polymers widely used as an electrical insulating or waterproof layer in the fields of semiconductor, electronics, and biomedical engineering owing to its outstanding properties of chemically inertness, biocompatibility, water resistance, low conductivity, and flexibility. It is increasingly required for real-time and non-destructive characterization of the deposition of parylene layer for the quality control and assurance. In the present work, we suggested an impedance measurement based parylene coating system which can provide the electrical properties of the deposited parylene in real-time and non-destructively. For this, the impedance spectra of parylene C, N, or D were measured using the fabricated interdigitated and wave-shaped electrode (IWE) during the chemical vapor deposition (CVD) process. The results showed a feasibility to monitor the impedance change according to the parylene deposition, and that the resistance at the frequency of 2.15 kHz was decreased in dependency on the type of the deposited parylene.