MORPHOLOGY OF THIN POLYIMIDE FILMS

A morphology of thin polyimide films prepared from polyamic acid solution has been investigated by scanning electron microscopy. A strong dependence between the conditions of post-preparation temperature treatment (imidization) and the structure and optical properties of the films has been found. The films exhibit a large optical anisotropy and well-defined columnar structure. This structure is supposed to explain the ''polyimide grass'' observed after reactive ion etching in an O2 atmosphere. Some techniques are proposed to avoid this effect in high yield microfabrication.