Authors: D.S. Kim, S-K Lee, S.S. Yang, T.H. Kwon and S.S. Lee
Affilation: Pohang University of Science and Technology,, Korea
Pages: 254 - 257
Keywords: microlens, modified LIGA process, prediction model, glass transition temperature (Tg), free volume theory
In this paper, we present a prediction model for microlens formation by means of a deep X-ray lithography followed by a thermal treatment of a PMMA (Polymethyl-methacrylate) sheet. According to this modeling, X-ray irradiation causes the decrease of molecular weight of PMMA, which in turn decreases the glass transition temperature and consequently causes a net volume increase during the thermal cycle resulting in a swollen microlens. Both a simple analysis and a Finite Element Analysis based on this model are found to be able to predict the variation pattern of the maximum heights of microlens which depends on the thermal treatment. The prediction model could be applied to optimization of microlens fabrication process.