Deep reactive ion etching of silicon using non-ICP-based equipment

Abstract

Deep reactive ion etching (DRIE) technology is one of the most important technologies in the processing of microelectronic devices and microelectromechanical system. As a necessary process in semiconductor integration, it has been widely studied in the past decades. It is known that the traditional DRIE process typically uses a plasma etching reactor equipped with inductively coupled plasma (ICP) sources to generate a high-density plasma so as to achieve high aspect ratio trenches with relatively small roughness. A cryogenic temperature control unit is typically employed as well. Here, however, we use a parallel plate RIE with rather simple structure, which is not usually used for DRIE, to obtain high aspect ratio silicon etching. With no ICP sources and no sophisticated temperature control unit, the system and experiment are now much more cost effective. Through the optimization of the processing, the etching rate of silicon can reach 440 nm/min. Finally, a 45 μm deep trench is etched in silicon with good perpendicularity. This method will greatly reduce the equipment related cost, especially for those applications that do not have extremely stringent requirement on the final etching accuracy.