Correlations between dissolution data and lithography of various resists

The fundamental basis of resist performance in semiconductor lithography is the creation of a dissolution gradient in the resist film. For positive resists the dissolution rate (DR) and dissolution characteristics of the exposed as well as unexposed regions are important factors in determining the performance of the resist. Since the establishment of the dissolution rate curve : as a method for evaluating photographic materials, many investigators have tried to correlate dissolution rate data with lithographic performance in a systematic way. In this work we will discuss the terms and factors used in analyzing dissolution data: R-min, R-max, developer selectivity, the shape of the dissolution rate curve, and the dissolution contrast, R-max/R-min We will then present data which demonstrates a correlation between some of these factors with either the observed resolution, exposure latitude, or the focus latitude; For focus latitude, correlations are shown for both blended polymer resists as well as other experimental resist systems. For exposure latitude, the experimental data suggests that a combination of factors are required. In addition to the experimental data, modeling results will be presented which verify the dissolution rate factors required for increased exposure latitude.