粘接胶粘弹性对加速度计热应力的影响研究

Study on effect of adhesive viscoelasticity on thermal stress of accelerometer

针对将粘接胶视为弹性材料建立的封装模型不能完全反映粘接胶材料特性与加载历史、时间和温度之间关系的问题,研究了粘接胶的粘弹性对硅微谐振式加速度计热应力的影响。首先,对粘接胶材料进行动态力学测试,得到粘接胶材料本构模型。其次,建立加速度计封装有限元模型,研究粘接胶松弛模量和热膨胀系数以及循环温度载荷对芯片结构应力的影响。研究结果表明:粘接胶材料参数、温度载荷与时间均会影响温度应力,低松弛模量与热膨胀系数接近于被粘接材料的粘接胶能够降低结构中的热应力,同时能够降低时间和多次循环温度载荷对应力的影响。

Aiming at the problem that packaging model based on elastic materials cannot reveal the relationship between material characteristics,loading history,time and temperature,effect of viscoelasticity of adhesive on thermal stress of silicon microresonant accelerometer is studied.Firstly,dynamic mechanical test is carried out to characterize the viscoelastic material properties of dieattach adhesive.Secondly,a finite element model is established for package of accelerometer.The effect of relaxation modulus and coefficient of thermal expansion of adhesive temperature load are studied.Research results show that the adhesive with low relaxation modulus and thermal expansion coefficient close to the adhesive material can reduce the thermal stress in the structure as well as reduce time and multiple cycles of temperature load.