Chalcogenide microlens arrays fabricated using hot embossing with soft PDMS stamps

摘要

This paper reports the development of a hot embossing method for fabricating chalcogenide microlens arrays using soft polydimethylsiloxane (PDMS) stamps. The stamps are formed by molding PDMS on photoresist masters fabricated with sphere segments by thermal reflow. Upon proper temperatures, the chalcogenide glass softens and is embossed using PDMS stamps with low pressure. Void defects at the center and at the side of microlenses are found, and the mechanisms for the void formation are investigated and verified. The hot embossing parameters including pressure, temperature, embossing time, and the thicknesses of the PDMS stamps are optimized. A 400 x 400 microlens array with uniform profiles, smooth surface roughness, and good roundness have been successfully fabricated on both chalcogenide thin films and bulk wafers. The preliminary results demonstrate the feasibility of using hot embossing with soft PDMS stamps as a simple and low cost method to fabricate chalcogenide microlens arrays.