关键词: 表面质量, 化学机械抛光, 微结构, 无压烧结碳化硅, 亚表面裂纹

Abstract: At present, the application of the micro-structured optical elements is continuously expanding, while the micro-structured surfaces should meet the required final quality to ensure the specific optical function. For example, collimation lenses for high performance diode lasers show an increasing industrial application with the requirement for micro-structured glass optical elements with cylindrical lens arrays, and the worse quality of cylindrical lens arrays may decrease the power output of the lasers. In essence, the optical properties of optical elements depend on the machined quality of the micro-structured mold used for the replication of the optical elements. However in consideration of the excellent property of pressureless sinter silicon carbide (SiC), the ground micro-structured surface quality is hard to meet the requirement, therefore the in-situ abrasive polishing of micro-structures of molds is proposed. The experimental results show that the surface roughness Ra and profile accuracy PV of the micro-structured surface decrease from 71.8 nm and 2.14 μm through grinding to 7.7 nm and 0.46 μm through abrasive polishing. In addition, the morphology of the polished groove tip is more integrated, while the tip radius R is expanded from 6.882 μm to 9.2936 μm after polishing. Moreover, although the sub-surface crack is not yet completely removed after polishing, the deepness of the crack is obviously shallow which effectively improve the service life of molds.

Key words: chemical mechanical polishing, micro-structured, pressureless sinter silicon carbide, sub-surface crack, surface quality