Research On Key Technology Of Fabrication Of Silicon Micro-hemispherical Resonator Gyro

Micro hemispherical resonant gyro is a micro device to measure speed or rotation Angle,which is a miniaturization design of traditional gyros.It not only inherited the advantages of the traditional gyroscope,also has small volume,low power consumption,can be mass production,the characteristics of high precision,widely used in consumer electronics products.In this paper,we study the structure design of micro hemispherical resonant gyro combines gyroscopes damping analysis and processing and error analysis,to make appropriate compensation structure.The hemispherical harmonic oscillator and SOI electrode cap are prepared separately by MEMS process.Then bonding assembly is completed in vacuum.The process flow chart of its preparation and design is combined with the existing process and equipment,and the process design and processing parameters are constantly improved in the process of production,so as to prepare the high-q micro-hemisphere resonator gyroscope.(1)To the preparation of hemisphere harmonic oscillator: take off the membrane,glass blowing process,burner method,on the basis of domestic and foreign research progress of micro hemispherical resonant gyro is expounded,including the prototype of the harmonic oscillator material,size,and the corresponding quality factor Q value,etc.,by comparing the them to introduce in this paper,the analysis and the research content and significance.(2)Using traditional pictorial hemisphere gyroscope to the working principle of this paper,the working principle of analysis,and the kirchhoff hoff hemisphere harmonic oscillator model and modeling based on circular harmonic oscillator model and correlation model,calculated the dynamic equation and precession factor,and the micro electrode distribution and velocity of hemispherical resonant gyro testing theory is analyzed.(3)The quality factor and energy dissipation of the micro-hemispherical resonator gyroscope are expounded,and the influence of materials and structural parameters of the micro-hemispherical resonator on support damping and thermoelastic damping is analyzed by using the COMSOL Multiphysics simulation software and PML technology for modeling.Then the main machining errors of the hemispherical oscillator are simulated and analyzed.(4)Combined with MEMS technology design the hemisphere of resonant gyroscope processing flow,key processing in micro polysilicon deposition and release of hemisphere harmonic oscillator,based on the established etching device and etching the HNA wet etching speed of the environment to test,get accurate etching time,producing micro hemisphere shell mold,and the alignment mark protection;Comparing the growth rate of the sacrificial layer oxide wet oxygen oxidation and the dry oxidation silica,the suitable deposition mode of the oxide layer was selected.Several groups of experiments were carried out to analyze and compare the parameters of deep pit spray,and better parameters were obtained to solve the problem of deep pit spray.The depth exposure parameters of the SPR220 photoresist,development time,and the uniformity of the opening of the support ring were studied.In combination with damping simulation analysis results and processing technology,polysilicon was selected to make spherical shell,and then doped annealing;The release of smooth symmetric spherical shell,the release of support column,the deep silicon etching of SOI cap electrode groove,the back electrode column and the sealing wall were realized,and the AU-SN vacuum sealing packaging technology was designed.