Han Chao, Li Cun, Zhao Yulong, Li Bo, Wei Xueyong
State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
Micromachines (Basel). 2020 Mar 24;11(3):337. doi: 10.3390/mi11030337.
Single-crystal quartz material is widely applied in the manufacture of resonators and sensors, but it is difficult to process because of its high hardness. A novel way to fabricate single-crystal quartz structures is proposed in this paper; the method includes quartz-on-silicon (QoS) technology and inductively coupled plasma (ICP) etching, which makes it feasible to fabricate complex structures with crystal quartz. The QoS method encompasses the bonding of silicon and quartz, followed by the thinning and polishing of quartz, which can enable the fabrication of an ultra-thin quartz wafer on silicon. In this way, instead of the conventional wet etching with hydrofluoric acid, the quartz layer can be easily etched using the ICP dry-etching method. Then, the structure of the pure quartz material is obtained by removing the silicon wafer. In addition, the silicon layer can be processed into the appropriate structure. This aspect overcomes the difficulty of processing a complex structure of single-crystal quartz with different crystal orientations. Thin single-crystal quartz wafers of Z-cut with a thickness of less than 40 μm were obtained by using this method, and a complex three-dimensional structure with an 80 μm width was also acquired by the ICP etching of the quartz wafer. The method can be applied to make both crystal-oriented quartz-based sensors and actuators, such as quartz resonant accelerometers.
单晶硅石英材料广泛应用于谐振器和传感器的制造，但由于其硬度高，加工困难。本文提出了一种制造单晶硅石英结构的新方法；该方法包括硅上石英（QoS）技术和电感耦合等离子体（ICP）蚀刻，这使得用晶体石英制造复杂结构成为可能。QoS方法包括硅和石英的键合，然后是石英的减薄和抛光，这可以在硅上制造超薄石英晶片。通过这种方式，石英层可以使用ICP干法蚀刻方法轻松蚀刻，而不是传统的氢氟酸湿法蚀刻。然后，通过去除硅晶片获得纯石英材料的结构。此外，硅层可以加工成合适的结构。这方面克服了加工具有不同晶体取向的单晶硅石英复杂结构的困难。通过该方法获得了厚度小于40μm的Z切单晶硅石英薄片，并且通过对石英晶片进行ICP蚀刻还获得了宽度为80μm的复杂三维结构。该方法可应用于制造基于晶体取向石英的传感器和致动器，如石英谐振加速度计。
