Mechanism And Experimental Study Of Ultrasonic-assisted Anodic Bonding Process

Anodic bonding is one of the key technologies in the packaging of MEMS.It is widely used in micro-gyroscopes,micro-electromagnetic field sensors,filters,acceleration sensors and energy collectors in micro-electromechanical systems because of its high mechanical strength,good sealing,high stability,low cost and the ability to connect heterogeneous materials.In the current anode bonding process,due to the high bonding temperature,it is easy to cause material thermal expansion coefficient mismatch,residual stress and damage to device structure.In view of these problems,after analyzing the application of ultrasound in mechanical processing,ltrasonic vibration is creatively applied to the anode bonding process in the packaging of MEMS.A composite anode bonding process based on ultrasonic vibration is proposed.By studying the mechanism of ordinary anodic bonding,the influence of various experimental conditions on the quality of anodic bonding is analyzed in depth,and a test platform is built.Through experimental research,combined with the transmission of ultrasonic energy,the relationship between the quality of anodic bonding and parameters under the combined conditions is explored,which provides a technological basis for low-temperature anodic bonding.By studying the mechanism of common anodic bonding,the effects of various experimental conditions on the quality of anodic bonding were analyzed in depth.Through experimental research,combined with the conduction of ultrasonic energy,the relationship between each parameter and the quality of anodic bonding under the combined conditions was investigated.Provides a process support foundation for low temperature anodic bonding.The full text of the specific study is as follows:Firstly,the process mechanism of traditional anodic bonding was studied.The influence of temperature on the resistivity of the material in anodic bonding was studied.The process of ion migration under electric field was studied.The influence of temperature and voltage on anodic bonding was analyzed.On this basis,the piezoelectric effect of the material is studied.By applying an excitation signal on the outer surface of the piezoelectric material(piezoelectric ceramic),the inverse piezoelectric effect is excited and the electrical energy is converted into mechanical energy.Through the study of the thermal effects of the viscous effect of ultrasonic vibration and the frictional heating,it is concluded that the frictional heating of ultrasonic vibration can better increase the temperature of the friction interface,theoretically analyzed.Ultrasonic activation of the surface of the material,the feasibility of the auxiliary anodic bonding process.Secondly,the ultrasonic assisted composite anodic bonding system was constructed.The ultrasonic assisted anodic bonding test bench was designed and built for the ultrasonic composite anodic bonding process.The test bench included motion control system,temperature control system,voltage and ultrasound.Control system,etc.According to the requirements of the test,a combined motion platform was designed,and the calculation of relevant parameters was carried out.According to the requirements of the test bench,the ultrasonic energy requirements were applied,and the important components were designed,and the ultrasonic vibrator fixture and silicon were designed and manufactured.Sheet clamps and glass clamps.Finally,the process experiment was carried out using an independently constructed ultrasonic assisted anodic bonding system.The relationship between temperature and voltage on the quality of anodic bonding was investigated by conventional anodic bonding experiments.On this basis,a comparative test was designed to verify the feasibility of the ultrasonic assisted anodic bonding process by comparing the hydrophilic angle of the material surface with the bonding strength of the bonding material,and by scanning electron microscopy(SEM)and energy spectrometer(EDS)The microstructure and elemental contrast analysis of the bonded intermediate layer.Three parameters of temperature,voltage and ultrasonic frequency were selected.The orthogonal experiment of three factors and three levels was designed to investigate the influence of three factors on the bonding strength.