Dependence on Latent Heat of Vaporization of Locally Thicker Thin Film Formation by Partial Heating of a Polymer Solution Film on the Substrate from the Bottom during Drying

The polymer resist coating process is important for precise semiconductor microfabrication, and a uniform polymer resist film thickness and homogeneous resist film quality are required. However, unevenness is observed on the resist film after drying. A cause of this unevenness is the non-uniform temperature in the device during drying. In this study, through numerical simulations we clarify the mechanism that explains why heating part of a polymer solution film on a substrate from the bottom produces a locally thicker film after drying, and the dependence of the unevenness of the film on the latent heat of vaporization. The larger the latent heat, the thicker the polymer resist film after drying in the heated region. This occurs because the temperature decrease caused by the latent heat of vaporization is recovered faster when the latent heat of vaporization is larger. 1School of Medicine, Fujita Health University, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi 470-1192, Japan. *Corresponding author