【作者】 陈兆鹏；

【导师】 褚金奎；

【作者基本信息】 大连理工大学 ， 机械工程， 2012， 硕士

【摘要】 微力传感器是微机电系统(MEMS)领域中不可缺少的一种传感器,在现有力传感器的研究中,能够对微小力测量的传感器相对较少。此外,在微装配和微操作过程中,为了避免破坏操作对象以及快速的完成操作,很多时候也都需要对力进行感知。本文设计了一款聚合物材料的微力传感器,并且采用了新颖的加工工艺将其制作出来,随后对其进行了相关的测试。本文选用SU-8胶作为微力传感器的基底材料,金属铜作为电极和压阻,利用电阻应变计的应变原理,从理论上分析了它与常用半导体式微力传感器的性能差别。SU-8胶微力传感器为典型的双层悬臂梁结构,根据被测对象的大小,本文确定了传感器的大体尺寸,又根据摸索出的工艺经验,确定了传感器的具体结构尺寸,最终设计了五种不同金属线宽的微力传感器。SU-8胶作为一种负性光刻胶,良好的耐腐蚀性以及生物兼容性使得此款微力传感器的应用范围更加广泛。为了制作SU-8微力传感器,本文探索研究了两种加工工艺。一种为剥离工艺,先加工出SU-8胶膜作为基底层,然后在上面涂胶,光刻出与金属层相反的结构,溅射金属铜后进行剥离操作。另一种为湿法腐蚀工艺,同样先加工出SU-8胶膜,然后在其上溅射金属铜,再涂胶,光刻出与金属层相同的结构,以这层结构为掩蔽层进行湿法腐蚀操作。最后再进行释放操作,就能得到此款微力传感器。为了便于进行微力传感器的测试,本文设计制作了传感器的外围电路,其中包括惠斯顿电桥电路、三级放大滤波电路和电源电路。电桥电路将传感器的电阻变化量转换为电压变化量。三级放大滤波电路将电桥的输出信号由μV级别放大到mV级别,并进行一定的滤波处理。电源电路主要是为放大电路提供±12V的工作电压。根据微力传感器的结构特点及测量需要,本文搭建了两套装置。一套为传感器的标定装置,其作用是完成对微力传感器偏转灵敏度的测量和力灵敏度的标定。标定结果显示10μm线宽的微力传感器综合性能最好,其力灵敏度为0.55mV/μN。另一套装置为微夹钳夹持力的测量装置,测量对象为本课题组设计制作的561钳口常闭型微夹钳。本文利用10μm线宽的微力传感器成功测量出了微夹钳不同钳口距离下的夹持力,并且将测量值与仿真值进行了比较。更多还原

【Abstract】 Micro-force sensor is a kind of indispensable sensor in the field of microelectro mechanical systems (MEMS). However, there are relatively few sensors for micro force detecting among the existing sensors. Furthermore, in order to prevent operation from damaging the object and complete the operation quickly, force needs to be measured in the process of microassembry and micromanipulation. This paper presents the design of a polymer micro-force sensor and novel processing technologies are adopted to make it. At last some related tests are done.SU-8is chosen as the substrate material for the micro-force sensor, copper as the electrode and the piezoresistance. Based on the strain theory of the resistance strain gauge, performance of the SU-8micro-force sensor is in comparison with that of the semiconductor piezoresistive micro-force sensor. SU-8micro-force sensor has a typical structure of double-layer cantilever. The specific structure size of the sensor is identified according to the size of measured object and explored process experience. And five kinds of micro-force sensors with different metal width are designed. As a negative photoresist, SU-8has good corrosion resistance and biological compatibility that makes the SU-8micro-force sensor more extensive in the scope of application.In order to make the SU-8micro-force sensor, two kinds of fabrication process are investigated in this paper. One is the lift-off process, which begins with the processing of a SU-8film as the basal layer of the micro-force sensor, and then makes the structure opposite to metal layer by spin-coating and lithography, at last sputters copper and processes the lift-off technology. The other is the wet etching process, including processing a SU-8film, sputtering metal on it and patterning the masking layer structure which is same as metal layer for wet etching using spin-coating and lithography. Finally SU-8micro-force sensor is obtained after releasing process.The sensor circuits are designed to facilitate the use of the SU-8micro-force sensor, including the Wheatstone bridge circuit, three-stage amplifying filter circuit and the power supply circuit. Resistance variation is converted into voltage variation by Wheatstone bridge circuit. And the μV-leveled signal is amplified with filter processing to mV-leveled one using the three-stage amplifying filter circuit. Power supply circuit mainly provides±12V voltage for the three-stage amplifying filter circuit.For the structure features of the SU-8micro-force sensor and the measurement needs, this paper puts up two sets of device. One set is the calibration system of the micro-force sensor, which is used for the deflection sensitivity measurement and the force sensitivity calibration. The results show that the combination property of micro-force sensor with10μm width is the best, and the force sensitivity is0.55mV/μN. The other set is clamping force measuring device, and the measuring object is jaw normally close561microgripper which is designed by this research group. Using the micro-force sensor of10μm width, we successfully measure the clamping forces of different jaw and compare the measured values with the simulation values.更多还原