Abstract
Researchers are currently exploring the use of acid-sensitive dyes to determine the quantity of acid generated from a photoacid generator (PAG) and to analyze acid-generating reactions. Requiring merely the addition to the resist of an acid-sensitive dye, which reacts with the acid generated from the PAG during the exposure and generates a color, this method makes it easier to grasp the PAG acid-generating action. The process involves applying a resist containing an acid-sensitive dye to a sample quartz substrate; making the exposure; and measuring and evaluating the absorbance of a chromogenic substance near 530 nm using a spectroscope. The method determines the rate constant for acid generation (the Dill C parameter) during the exposure based on the relationship between transmissivity at 530 nm and the exposure dose. However, the chromogenic substance used in this method gradually degrades after the exposure, resulting in time-dependent variations in transmissivity. With this in mind, we devised a measurement system capable of in situ measurements of absorbance at 530 nm during exposures of a 193-nm light beam. Using this system, we obtained rate constants for acid generation, C parameters, and compared the effects of ArF resist polymer (with and without blocking groups) of different structures and various PAG types, as well as the dependence on the quantity of the quencher. The results of our experiments indicate a new model that accounts for the quencher concentration parameter would be useful in analyzing dependence on the quantity of quencher. This paper presents these findings.
