Annealing for the improvement of the capabilities of parylene C as electret

Copolymerization of Parylene C and Parylene F to Enhance Adhesion and Thermal Stability without Coating Performance Degradation

Parylene C has been widely used in the fields of microelectromechanical systems (MEMS) and electronic device encapsulation because of its unique properties, such as biocompatibility and conformal coverage. However, its poor adhesion and low thermal stability limit its use in a wider range of applications. This study proposes a novel method for improving the thermal stability and enhancing the adhesion between Parylene and Si by copolymerizing Parylene C with Parylene F. The successful preparation of Parylene copolymer films containing different ratios of Parylene C and Parylene F was confirmed using Fourier-transform infrared spectroscopy and surface energy calculations. The proposed method resulted in the copolymer film having an adhesion 10.4 times stronger than that of the Parylene C homopolymer film. Furthermore, the friction coefficients and cell culture capability of the Parylene copolymer films were tested. The results indicated no degradation compared with the Parylene C homopolymer film. This copolymerization method significantly expands the applications of Parylene materials.