Preparation and Patterning of Optical Hybrid Thin Films Based on Photosensitive Polyimide and Monodispersed Colloidal Silica

Abstract

In this study, optical hybrid thin films were prepared from photosensitive poly(4,4-(hexafluoroisopropyl- idenediphthalic anhydride)-co-oxydianiline) (6FDA-ODA)/MDAE and monodispersed colloidal silica with a coupling agent. It was a combination of the sol–gel reaction, thermal polymerization and spin coating. The coupling agents were 3-methacryloxypropyl trimethoxysilane (MPTMS) or (4-vinylphenethyl)trimethoxysilane (VPTMS). The silica content in the hybrid thin films was varied from 0 to 8.6wt%. The coupling agent and the silica domain were designed primarily for reducing the volume shrinkage and enhancing the thermal properties, respectively. The retention of MDAE in the prepared hybrid films is supported by X-ray photoelectron spectroscopy (XPS). The silica domain significantly enhanced the thermal properties of the prepared hybrid films in comparison with parent fluorinated polyimide. The prepared hybrid materials also exhibited reduced refractive index by increasing the silica content. The results of SEM showed the prepared photosensitive hybrid materials could obtain lithographical patterns with a good resolution. These results indicated that the newly prepared photosensitive polyimide/colloidal silica hybrid thin films had potential applications for optical devices.