Dissolution behavior of resist polymers studied by Quartz-Crystal-Microbalance method II

Characteristic matrix method was applied to study the anomalous Quartz-Crystal-Microbalance (QCM) data such as sequential peaks of resonance frequency and impedance. The formation of swelling layer was found to cause the broad peak of resonance frequency at the beginning of development. An impedance peak followed the frequency peak when the rigidity of the swelling layer decreased to ca. 105 Pa due to absorption of the developer. Constant thickness of a swelling layer makes double sets of sequential peaks in frequency and impedance. Continuous changes in swelling layer thickness caused a single set of peaks during development. A fast data-acquisition system for QCM was set up and showed the sampling time of 1 kHz with the accuracy of 0.5 nm. It gives good and precise information for resist of large dissolution rate and interface region between resist and substrate.