ABSTRACT
References ....................................................................................................................................144
Optical lithography modeling began in the early 1970s at the IBM Yorktown Heights
Research Center, when Rick Dill began an effort to describe the basic steps of the litho-
graphy process with mathematical equations. At a time when lithography was considered
a true art, such an approach was met with considerable skepticism. The results of their
pioneering work were published in a landmark series of papers in 1975 [1-4], now referred
to as the Dill papers. These papers not only gave birth to the field of lithography modeling,
they represented the first serious attempt to describe lithography as a science. They
presented a simple model for image formation with incoherent illumination-the first-
order kinetic Dill model of exposure-and an empirical model for development coupled
with a cell algorithm for photoresist profile calculation. The Dill papers are still the most
referenced works in the body of lithography literature.
