Study on new method and mechanism of microcutting-etching of microlens array on 6H-SiC mold by combining single point diamond turning with ion beam etching

摘要

Silicon carbide (SiC) is a kind of ideal mold material for precision glass molding (PGM). However, for the traditional processing methods, the fabrication of large-area and high-accuracy microlens arrays on SiC is still faced with many difficulties because of its high brittleness and rigidity. Therefore, an integrated microcutting-etching method, which combines single point diamond turning (SPDT) with ion beam etching (IBE), is proposed and explored within this paper. This new method aims to provide a solution for the microlens machining on the hard or brittle materials. In order to improve the microlens accuracy, we investigated the microlens profile evolution mechanism on the 6H-SiC mold during IBE process and established a reverse model to design the mask shape for SPDT. The microcutting-etching machining for the fabrication of microlens array was conducted on both Si and SiC substrates. Three groups of the ring-shaped microlens arrays with different sizes were obtained on Si and SiC substrates, respectively. The experiment results show the validity of the profile evolution mechanism and the feasibility of the reverse design model. The microcutting-etching method is proved to have prospective potentials in the fabrication of microstructures on the hard or brittle materials.