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Study of high aspect ratio silicon etching based on ICP

The etching process of the high aspect ratio of Si deep trench is the key technology in MEMS field. Having used Oxford Plasmalabsystem100 ICP-180 etcher with SF6 and C4F8 as the etching gas, the influence on the deep Si etching process of Bosch under different ICP power, bias voltage, temperature, pressure and other parameters has been studied. The experimental result shows that under appropriate parameters, the high-aspect ratio of silicon deep trench is greater than 26:1, the sidewalls’ vertical degree is 89.9°, and the etching rate is greater than 2μm/min; the high aspect ratio of SOI deep trench is greater than 28:1, the sidewalls’ vertical degree is 89.7°, and the etching rate is greater than 2μm/min.