Process Optimization And Structural Test Of Micro Hemispherical Resonator Gyroscope

Micro hemispherical resonant gyroscope??HRG?has become one of the hot directions in the field of MEMS device research,with its advantages in small size,high precision,low power consumption,long service life and mass production,which has become the focus of domestic and foreign research institutions.In this paper,the energy dissipation and frequency cracking mechanism of the?HRG are analyzed,the structure design is also included.Emphasis of this paper is to design actual fabrication process flow and optimize the specific fabrication steps.The goal is to fabricate the?HRG with high quality factor.Firstly,the research and forms of?HRG and related technological methods are expounded,which will explicit the value of the project and provide useful reference for modeling simulation,structural design and fabrication process design of the?HRG.Secondly,the working principle,motion equations and precession characteristics of the?HRG oscillator are established by using the hypothesis of Kishhofy-Liyev theory.Two working modes of the?HRG are introduced in detail,including the position and parameter excitation,which provide the theoretical basis for the follow-up work.Thirdly,the energy dissipation form and frequency cracking mechanism of the?HRG are explained.Through Comsol Multiphysics,the effects of?HRG materials on thermal elastic damping,as well as the structural parameters on the support loss are analyzed in detail.The mathematical model derivation and solution of the modal frequency cracking method can provide the simulation foundation for the structure design of the?HRG.Fourthly,two forms of hemisphere harmonic oscillator structures are designed.By harmonic response analysis with ANSYS,harmonic oscillator structure with no lip is determined as the designing scheme.Simulation analysis of structural error in fabrication process is carried out,including errors in shell thickness,roundness of shell lip,shell height,support column height and eccentric,which provides theoretical guidance for the design.Finally,the whole fabrication process is designed,and emphasis is the comparison of SF₆ dry etching and HNA wet etching for the improvement of technological parameters and hemisphere mold fabrication quality through experiments and tests.According to the material characteristic,thin film depositing polysilicon and in situ doping technology is chosen for hemisphere harmonic oscillator.Optimization and improvement of electric conduction way is included as well.Initial assembly between electrode and oscillator,and measurement of plate gap are completed.