硅压敏电阻刻蚀形貌对高温压力传感器输出特性影响

Output Characteristics Influence of Silicon Piezoresistor Etching Morphology on High Temperature Pressure Sensors

为解决压力传感器在高温下的热零点漂移问题,文中提出一种压敏电阻均匀刻蚀的方案。通过控制变量法改变沉积和刻蚀聚合物时序参数,解决了制备硅电阻条出现的微负载效应,减小了压力传感器中惠斯登电桥不平衡性。对比了不同参数下的刻蚀效果,得出最佳刻蚀参数为1个循环内钝化时间2 s、刻蚀时间4.8 s,刻蚀图案成功保持了设计图形的关键特征,电阻条连接处曲线平滑、侧壁角度锐利,垂直度达到了88.6°。最终制备的芯片在300℃环境下进行压力测试,测试结果表明传感器芯片热零点漂移率降低了46.7%,验证了该方案对改善芯片高温下热零点漂移的可行性。

In order to solve the problem of hot zero-point drift of the pressure sensor at high temperature,a scheme with uni-formly etching of pressure-sensitive resistance was proposed.The sequential parameters of the sedimentation and etching polymer were changed by controlling the variable method,which solved the microloading of preparing silicon resistance bars,and reduced the imbalance of Wheatstone bridge in the pressure sensor.Comparing the etching effect under different parameters,the best etch-ing parameter was that the passivation time was 2 s and the etching time was 4.8 s in a single cycle.The etching pattern success-fully maintained the key feature of the design graphics,the resistance bar connection curve is smooth,the side wall Angle is sharp,and the perpendicularity reaches 88.6°.The final prepared chip was tested under pressure at 300℃,and the test results show that the thermal zero drift rate of the sensor chip is reduced by 46.7%,which verifies the feasibility of the scheme to im-prove the thermal zero drift of the chip at high temperature.