基于MEMS技术的低g值微惯性开关的设计与制作

Design and Fabrication of Low-g Micro Inertial Switch Based on MEMS Technology

惯性开关是一种感受惯性加速度,执行开关机械动作的精密惯性装置。选用典型的"弹簧-质量-阻尼"结构,研制了一种基于平面矩形螺旋梁的低g值(1gn^30gn)微惯性开关。惯性敏感单元由一个方形质量块和支撑它的两根螺旋梁组成,采用ANSYS有限元软件对其进行了仿真分析。采用MEMS体硅加工工艺和圆片级封装技术,包括KOH腐蚀、ICP刻蚀和喷涂工艺等关键工艺技术,完成了微惯性开关的制备,划片后芯片尺寸为7 mm×7 mm×1.5 mm。经离心实验测试,微惯性开关的闭合阈值约为4.28gn,导通电阻约为9.3Ω。多次测试结果表明,微惯性开关具有0.5gn的闭合精度,多次测试重复性较好,具有体积小,结构简单,加工容易实现等特点。

The micro inertial switch is a kind of inertial device sensitive to the acceleartion and achieving the switch closure when subjects to the applied accelearation.A low-g（1gn^30gn）micro inertial switch based on the planar rectangular helical spring was developed.The structure of the switch is the classical spring-mass-damping system.The inertial sensing element containing a sensor mass and two springs was analyzed utilizing the ANSYS finite element method.The micro inertial switch was fabricated using the MEMS bulk micromachining process and packaged in wafer level,including the crucial technology of KOH etching、ICP etching spray coating method,and so on.The bulk of chip is about 7 mm×7 mm×1.5 mm in size.The threshold value is about 4.28gn,and the on-state resistance is about 9.3 Ω by laboratory centrifuge test.It is shown that the closed precision of the micro inertial switch is about 0.5gn and the repeatability in multiple tests is good.The advantages of the switch are small size,simple structure and easy fabrication.