3D structural foramation utilizing glass transition of a Parylene film

This paper reports on a fabrication method of three-dimensional micro structures supported by a Parylene thin film. The three-dimensional structure formation procedure starts with an out-of-plane actuation of the Si surface micromachined structure coated with a thin Parylene film. At the same time of the actuation, the environmental temperature was elevated above the glass transition temperature T_g of the Parylene, 80-100 °C, and then cooled down below T_g. In this process, the rearrangement of the Parylene film happens above T_g, and the consolidated Parylene after the cooling down maintains three-dimensional micro structures as actuated. In a proof-of-principle experiment, the three-dimensional spiral structures formed by 300-nm-thick silicon were fixed by 1-μm-thick Parylene film.