Fabrication of SiC concave microlens array mold based on microspheres self-assembly

Microlens array (MLA) is applied widely in imaging, lighting, and sensing fields. Among the many techniques for MLA fabrication, molding is considered to be a mass-production method with low-cost and good accuracy. Silicon carbide (SiC), which has a high mechanical hardness, high thermal conductivity, and low thermal expansion coefficient, is an ideal mold material. But to fabricate microlens array on SiC by the mechanical method is a challenging issue because of its high brittleness and hardness. In this study, a novel method is proposed and developed, in which we use self-assembled silica microspheres monolayer as a template for SU8 resist patterning, subsequently producing concave MLAs in the SiC substrates by Inductively Coupled Plasma (ICP) etching. Two sizes of hexagonal MLAs (diameter Φ11 μm and height 0.8 μm, diameter Φ33 μm and height 2.9 μm, respectively) have been created and tested to possess good imaging performance.