The resist materials used today in the fabrication of semiconductor devices were not expressly designed for this application. They were originally developed for use in the printing industry and were simply adopted by the electronics industry with relatively minor modifications. The performance of these resists was more than adequate for initial applications and, as a result, it was not necessary completely understand the chemistry responsible for lithographic behavior. However, the current resolution requirements and severe processing conditions in device manufacturing make it necessary to understand resist chemistry not only to maximize the performance of available materials but also to allow for the rational design of new materials. The paper discusses three topics which demonstrate that one can specifically design a resist system for optimal performance. The first deals with the generation of a negative tone image from a positive photoresist. The second topic addresses techniques for significantly reducing the time required to expose a resist. And finally, the materials requirements for the next generation of multilayer resist (MLR) systems will be discussed. © 1983.