Study on the Surface Roughness Improvement for Silicon Samples with Millimeter-Size Openings

Substrate-free MEMS and MOEMS devices are becoming the hotspots for micro systems. Fabrication of substrate-free devices usually involves the release of backside silicon through the deep reactive ion etch (DRIE) process. And smoothness of etch cavities during DRIE is of vital importance for the performance of devices. The electrical state of electrically isolated samples was optimized to obtain better roughness when etching parameters were fixed. After the isolated sample was electrically grounded, the number of etch grass on the surface decreased and lower root-mean-square roughness was obtained. This technique helps in the fabrication of substrate-free micro-system devices.