Silicon wafers with micro patterns have been increasingly required in advanced optics for excellent optical performancein the infrared region. However, the costly and inefficient fabricating methods for them severely limit their applications.In this work, we present an economic and efficient grinding-polishing approach for fabricating concave microlens arrayon silicon wafers. Different from traditional processes for microlens array on silicon wafers, the paper demonstrates achemical mechanical grinding-polishing (CMGP) process by grinding micro cavities on silicon wafer and then polishingthem to precision concave microlenses with ball-end tool, polishing pad and diamond slurry. A new experimental setupwith entire mechanical structure and electronic control program was established to validate the feasibility of this newmethod. During the CMGP process, in order to gain microlens array with specific apertures, a material removal modelfor micro cavity grinding process was established to accurately calculate cavity depth by using grinding parameters andthe model was validated by grinding experiments. Guided by this model, a 10 ×10 large-area microlens array wasfabricated on silicon wafer. In addition, the surface profiles and roughnesses of the microlens array were also evaluated.
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