基于(111)硅单片集成三轴加速度计的工艺研究

Study on Monolithic Integration Technique of 3-Axis Accelerometers Based on(111)Silicon Wafer

介绍了一种新型单片集成电容式三轴微加速度计的加工方法,该方法采用非绝缘体上硅(SOI)的单硅片单面加工技术,易于与IC工艺兼容,而且成本低廉,成品率高,适用于批量生产,可替代传统的SOI工艺。该方法主要利用硅深度反应离子刻蚀(DRIE)技术结合普通(111)单晶硅片内部可选择性横向自停止腐蚀技术制作并释放得到悬浮可动的敏感结构。此外,创新的锚点设计不仅使检测电极之间相互电学隔离,而且便于引线键合与封装。最后基于开环接口电路对加工制造的三轴加速度计进行了测试,验证了该工艺的可行性。

A novel processing method for the monolithic integration of 3-axis capacitive accele- rometers was introduced, and the single-wafer-based single-sided micromachining technology without silicon on insulator （SOI） was used in the method. The advantages of the method are compatible with IC, low lost, high yield, suitable for mass production and can replace the tradi- tional SOI technology. The silicon deep reactive ion etching （DRIE） technology combined with the （111） silicon wafer inside selective transverse self-stop wet etching technology was mainly used to fabricate and release the movably sensitive structure in the method. In addition, the novel anchor structure was designed to make the detection electrodes electrically isolated from each other and the bonding and packaging more convenient. Finally, the fabricated 3-axis accelerome- ter was tested based on the open-loop interface circuit, and the feasibility of the novel technology was verified.