The use of acid sensitive dyes to determine the quantity of acid generated from PAG and in the
analysis of acid-generating reaction is currently being studied. The method would allow an easy
understanding of the PAG acid-generating reaction simply by adding an acid sensitive dye to the
resist. In the conventional method, a resist containing a chromogenic substance is applied to a quartz
substrate, which is then exposed. Following the exposure, the absorbance of chromogenic
component near 530 nm is measured and evaluated with a spectroscope. The rate constant for acid
generation (Dill's C parameter) during the exposure is determined based on the relationship between
transmittance at 530 nm and the exposure dose. However, the chromogenic substance used in this
method degrades over time (fading reaction) after the exposure, resulting in variations in
transmittance measurements due to the effects of time between the completion of the exposure and
the measurement of transmittance. We devised a prototype instrument capable of in situ
measurements of absorbance at 530 nm while irradiating a 193-nm light beam. Using this instrument,
we obtained rate constants for acid generation (Dill's C parameter) and examined the differing
results obtained with ArF resist polymers of differing PAG concentrations and structures as well as
dependence on the quantity of the chromogenic substance.
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