Planarization and Dielectric Properties of Thin Photosensitive and Nonphotosensitive BCB

Abstract

Thin films (0.2 μm to 1.8 μm) of photosensitive and nonphotosensitive BCB were fabricated and the degree of planarization (DOP) and dielectric properties were investigated. It was found that a high DOP for wide spaces (>20 μm spaces with 1 μm of BCB) was possible with nonphotosensitive BCB but not photosensitive BCB because of the cross-linking reaction during the photo-process. Thin films (as thin as 0.2 μm) exhibited dielectric properties similar to thick films. The dielectric properties of the photosensitive BCB were slightly higher than nonphotosensitive BCB. Low loss properties were observed at all thickness.