5.1 Exposure Kinetics

The kinetics of photoresist exposure is intimately tied to the phenomenon of light absorption. Generally speaking absorption can be described on a macroscopic or on a microscopic scale. Whereas the macro-level relates the exposing light to the amount of absorbed energy via the so-called absorption coefficient, the micro-level yields chemical models for this macroscopic quantity. Thus we first discuss the physical basics of light absorption in an arbitrary dilute solution, before we present the two exposure models describing the chemical reaction occurring in conventional and chemically amplified resist systems.