LIMITS OF OPTICAL LITHOGRAPHY.

Abstract

Two dimensionless constants are used to describe limitations of optical image formation. The above constants were obtained from experimental exposures on a step and repeat camera. The effect of these parameters on image forming properties of various optical schemes is discussed. Attaining high resolution images over an extended area required development of novel lens configurations, illuminating systems, cameras and mechanical stages. Also, the manufacturing of optical surfaces and lens mounting had to be perfected. These developments, which have occurred over a period of 20 years and gave rise to a new industry, are reviewed and limitations imposed by physics are discussed.