Research on the cast molding process for high quality PDMS molds

As a critical component in nanoimprint, PDMS mold is usually made by cast molding, and it is important to make high quality PDMS molds with fine, dense and deep features. A number of methods have been developed to improve the quality of the mold. However, they are mainly focused on the additives added to the polymers which will enhance the performance of PDMS mold. In this paper, two major factors in the cast molding process which will affect the physical properties of the final PDMS mold are investigated: the vacuum degree in degassing phase and the curing temperature in solidifying phase. The experiments have indicated that a higher vacuum degree and a lower temperature are the favorable conditions to make a quality PDMS mold. Moreover, through the obtained experiments results, the curing mechanism of PDMS is further revealed. As a result, the dense and fine features with a linewidth of 40 nm in the PDMS mold have been replicated from the master pattern by cast molding process successfully.