Fabrication of anti-reflective structure array on chalcogenide glass by compression molding with polydimethylsiloxane mold

Abstract

.The feasibility of the proposed new process chain was demonstrated by generating an anti-reflective (AR) structure array with continuous profile on a chalcogenide glass substrate. First, a soft mold made of polydimethylsiloxane (PDMS) was created by casting and lift-off process off a Si master mold with original AR features. The master mold can be reused to create multiple PDMS molds. Afterwards, a nonisothermal compression molding process was conducted using PDMS soft mold to replicate a moderate aspect ratio AR structure array from PDMS mold onto chalcogenide glass surface. PDMS mold was first heated to a low temperature around 190°C such that its rigidity can be maintained, whereas the chalcogenide glass was heated to a relatively higher temperature around 240°C for molding. Surface profiles for both PDMS mold and molded glass were evaluated using both Wyko optical surface profilometer and scanning electron microscope tool. For optical performance, an optical light transmission test was conducted. We demonstrated that PDMS can be a good candidate for mold material in chalcogenide glass compression molding process in replicating large surface arrays with moderate aspect ratio structures.