Study of Swelling Behavior in ArF Resist during Development by the QCM Method (3) - Observations of Swelling Layer Elastic Modulus

The QCM method allows measurements of impedance, an index of swelling layer viscosity in a photoresist during development. While impedance is sometimes used as a qualitative index of change in the viscosity of the swelling layer, it has not so far been used quantitatively, for data analysis. We explored a method for converting impedance values to elastic modulus (Pa) and a coefficient expressing viscosity. Applying this method, we compared changes in the viscosity of the swelling layer in an ArF resist generated during development in a TMAH developing solution and in a TBAH developing solution. This paper reports the results of this comparative study.