Micro-forming of PMMA for optical components

This paper describes the micro forming of polymethyl methacrylate (PMMA) to fabricate an array of micro mirror for an optical switch component. A die for micro forming is fabricated from Si master die by Ni electroforming and the subsequent KOH etching in order. Micro forming is performed by transferring the configuration of micro die to PMMA with a hot embossing system. To obtain the enough height and the required configuration of mirror, it is found that the forming and die release temperature should be 403 K, and 363 K, respectively. However, all of the fabricated mirrors incline toward the array center, and the inclination angle increases with a distance from the center. FEM analysis indicates that the inclination of the mirror is due to the difference of thermal contraction between Ni die and PMMA. Therefore the micro die must be designed in full consideration of thermal contraction to obtain a high dimensional accuracy in micro forming.