Research On Capability MEMS Resonator Performance Changes Caused By Process Errors

Micro Electro Mechanical systems(MEMS)utilize micro-processing techniques of integrated circuits and,with their miniaturization,low cost,and integrated excellent performance,is widely used in many cross fields,such as automotive electronics,health care,telecommunications and so on.As a member of the MEMS device,capacitive radial resonator is also a research focus in recent years.In this thesis,changing performance of MEMS capacitive radial resonator caused by the two manufacturing processes is studied in the following aspects:In part 1,the influence of the non-smooth side surface between the resonator and the input/output electrode on the performance of the resonator under the TMDE manufacturing process was studied.Based on this,the manufacturing process and principle of TMDE were studied,and two models were deduced: the groove model and the fan-shaped fold model,and the relationship between the performance of the resonator and the model was established.The results show that the resonator capacitance,electrostatic force,electrical stiffness,and output current are all reduced but the motion resistance is increased.When the groove height is 1um,the width is 4nm,the electrostatic force,electrical stiffness and output current are reduced to 67.343%,57.626%,and 40.840%,respectively,and the movement resistance is increased by 2.45 times.The corresponding relationship between performance and process was deduced.It was found that when the performance was reduced by 25%,the above performance equivalent spacing was 23.094 nm,22.013 nm,21.491 nm,and 18.612 nm.In part 2,the influence of the tilt effect between the resonator and the electrode on the performance of the resonator in the radial disc resonator under the DRIE process was studied.Firstly,the manufacturing process of DRIE is studied,and the relationship between the tilt and the performance of the resonator is established.The influence of the tilt effect on the performance of the resonator,including output current,the electromechanical coupling efficiency,and the resonant frequency are analyzed.The results show that as the tilt angle increasing,the time-varying capacitance,output current,and electromechanical coupling efficiency gradually decrease,but the resonant frequency increases.When the tilt angle is0.2°,the initial capacitance decreases by 2.56%,the output peak current decreases by 21%,and the frequency rises by 84 ppm.Under the 15 V DC bias voltage,the tilt angle increases from 0.1°to 0.14°,the electromechanical coupling efficiency decreases by 63.5%.The electromechanical coupling efficiency is improved by increasing the DC voltage.However,under the traction of the electrical stiffness,the resonant frequency will increase with the increase of the tilt angle,the electrical stiffness produced by the bias voltage will make the frequency rise more significant,and the error is further amplified,when the bias voltage rises from 8V to 16 V,and the resonance frequency shifts from 17 ppm to 68 ppm.In part 3,it is about problem of coupled beam deviation of the double disc capacitive MEMS filter and performance variation of the filter caused by DRIE process.The paper makes a detailed theoretical analysis of the influence with the filter performance,which caused by the change of resonator performance under process error.The influence of the tilt of the DRIE process on the performance of the filter and the effect of the beam length on the coupling frequency,combined with the existing radial vibration equivalent circuit model,analyzes the performance variation of the resonator within the deviation value,and analyzes the effect of the equivalent circuit pattern on the resonator.The impact of the bottom.The MEMS filter designed by the simulation results showed that the beam length is 26.5265 um,and the bandwidth increases with the increase of the coupling beam length;the results show that with the increase of the tilt angle,the filter band is right-biased overall,when the tilt angle increases from 0.5°to 2.5°,the center frequency increases by 0.1425 MHz,increases by 0.1682%,the lower cut-off frequency rises by 0.139 MHz,and the upper cut-off frequency rises by 0.14 MHz.