Dissolution behavior of resist polymers studied using quartz crystal microbalance method

Abstract

The quartz crystal microbalance (QCM) method was used to obtain precise information about the dissolution behavior of resist polymers. The time evolutions of the resonance frequency and the impedance during the dissolution were measured using the QCM method. The data were simulated using the transmission line method on a four-layer model. Transmission line analysis showed Sauerbrey’s relation to be invalid during the formation and dissolution of the gel layer, although Sauerbrey’s relation was valid during the other development time with the constant thickness of the gel layer. The application of Sauerbrey’s relation in those transition areas brought out artificial changes of the dissolution or swelling rates. The rigidity of the gel layer was also analyzed from 10² to 10⁷ Pa using the transmission line method. The resonance frequency changed drastically at less than 10⁵ Pa during the formation and dissolution of the gel layer. The application of Sauerbrey’s relation in those transitional areas resulted in artificial changes of the dissolution rate from 5 nm/s to 92 nm/s and a shortening of the induction period from 5 s to 2.5 s. Transmittance analysis has shown the validity of quantitative analysis in QCM experiments.