MORPHOLOGY OF THIN POLYIMIDE FILMS

A morphology of thin polyimide films prepared from polyamic acid solut ion has been investigated by scanning electron microscopy. A strong de pendence between the conditions of post-preparation temperature treatm ent (imidization) and the structure and optical properties of the film s has been found. The films exhibit a large optical anisotropy and wel l-defined columnar structure. This structure is supposed to explain th e ''polyimide grass'' observed after reactive ion etching in an O2 atm osphere. Some techniques are proposed to avoid this effect in high yie ld microfabrication.