PHOTOLITHOGRAPHIC PROCESSES IN AMORPHOUS SEMICONDUCTORS

Abstract
Various photolithographic processes in a wide class of amorphous semiconductor films have been proposed and demonstrated in the past decade. The special features of the photosensitive amorphous semiconductor materials - non graininess, inorganic chemistry, deposition from the vapor phase and durability in dry and wet etchants - make them attractive photoresists for sub-micron fabrication of integrated circuits and integrated optics devices. The photolithographic processes in amorphous semiconductors can be classified according to four photosensitive effects : [1] light enhanced chemical reactivity, [2] photodissolution of metals, [3] light enhanced vaporization and [4] light induced crystallization. For each of these processes the mechanism, the sensitivity and the resolution are described with reference to published data, and its merit for the fabrication process of integrated circuits is discussed. Applications in which the photosensitive materials can serve as the final micro-component are emphasized.