Influence Of Adhesive Non-uniformity On The Thermal Drift Of Micro-accelerometer

The capacitive micro accelerometer(CMA)has many advantages,such as high sensitive,structure simple,easy integration.As a kind of micro sensors,CMA developed the fastest and the most widely used commercial applications.The environmental temperature variation leads to bias thermal drift of CMA,which seriously affects the detection accuracy and restricts CMA whether can be applied into high-end filed.In the packaging process,the adhesive non-uniformity and void will inevitably occur,the environmental temperature variation will lead to the asymmetric thermal stress and thermal deformation of CMA,resulting in bias and bias thermal drift.With the increasing of the detection precision,the influence of the adhesive non-uniformity on the bias temperature drift of CMA can’t be ignored.In recent years,there is little research about the influence of adhesive non-uniformity on the bias thermal drift of CMA.Therefore,it is of great engineering significance to investigate the influence of the adhesive non-uniformity on the bias thermal drift.The main contents are:1.CMA is simplified into three layers,the middle layer is uniform through theoretical derivation to obtain the axial displacement on the glass surface,and the axial displacement and shear stress at the interface between the adhesive layer and the glass in the three-layer structure with the middle layer non-uniformity is obtained,and compared with the finite element simulation analysis.The influence of adhesive non-uniformity on the bias thermal drift of CMA is analyzed by simulation,and the bias thermal drift doesn’t change linearly with the change of the inclination angle.In addition,the effect of the asymmetry of the folded beam on the bias thermal drift of CMA is analyzed,and the influence of the asymmetry of the folded beam on the bias thermal drift of the accelerometer is significant.2.Analysis of adhesive non-uniformity under the adhesive void position distribution and adhesive void size to influence the micro accelerometer bias,void at different positions of CMA bias is different;when the void is symmetrically distributed on the left and right sides of the adhesive,the left and right sides of the bias regularity is same,however the adhesive thickness the smaller the value is larger,the effect of the void size on the bias is complex,the void located in the support folded beam anchor corresponding to adhesive position is sensitive to accelerometer.3.The influence of different elastic modulus of adhesive on the bias is analyzed,situations of three kinds are considered,such as the adhesive non-uniformity,the adhesive non-uniformity and folded beam asymmetry,the adhesive non-uniformity and void.The different elastic modulus of the adhesive makes the micro accelerometer structural deformation different,resulting in micro accelerometer bias.