电阻悬浮的MEMS热膜式气体流量传感器设计

设计了一种新型电阻悬浮结构的热膜式气体流量传感器,具有测量精度高、灵敏度好、抗压能力强、微加工工艺简单等特点。采用ANSYS软件对传感器芯片在不同流速下的温度场进行了有限元仿真,得出了上下游温差与流速的关系曲线。通过比较热膜电阻非悬浮与悬浮时的导热损失和压力分布,得到了将热膜电阻悬浮的流量传感器的性能要优于一般传感器的结论,其灵敏度为一般传感器的3.6倍。分析表明,传感器的响应时间仅为0.17 ms,比一般传感器快了好几倍;流速在0～0.5 m/s和0.5～2.5 m/s时,传感器输出信号都有较好的线性度,使其能够应用于小流量和大流量的测量当中;流道高度为150μm时,流量为0～2.7 L/h。根据工艺条件和仿真结果,确定了传感器芯片的结构尺寸和微加工工艺流程。

Design of the MEMS Thermal-Film Air Flow Sensor with Suspended Resistors

A novel thermal-film air flow sensor with suspended resistors was presented.The sensor has advantages of high measurement accuracy,good sensitivity,compressive resistance and simple micromachining process.The temperature field in different velocity conditions of the flow sensor was simulated with finite element analysis method by ANSYS software,and the relation curve between the temperature variation and flow velocity was obtained.By comparing the conductive heat losses and pressure distribution between the sensors with and without suspended resistors,it is concluded that the performance of the sensors with suspended resistors is better,and its sensitivity is 3.6 times that of the traditional one.Theoretical analysis shows that the respond time of the sensor is only 0.17 ms,which is several times faster than other sensors.When the flow velocity is in the range of 0-0.5 m/s and 0.5-2.5 m/s,the output signals of the sensor have good linearity,and the sensor can be used for the measurement of small flow and large flow. The flow of the sensor is 0-2.7 L/h when the flow channel height is 150 μm.According to the process conditions and simulation results,the structural parameters and micromachining process of the sensor were given.