School of Electronics Engineering, College of IT Engineering, Kyungpook National University, Daegu 41566, Korea.
The 3rd R&D Institute-4th Directorate, Agency for Defense Development, Daejeon 34186, Korea.
Sensors (Basel). 2019 Sep 14;19(18):3979. doi: 10.3390/s19183979.
Die attach is a typical process that induces thermal stress in the fabrication of microelectromechanical system (MEMS) devices. One solution to this problem is attaching a portion of the die to the package. In such partial die bonding, the lack of control over the spreading of the adhesive can cause non-uniform attachment. In this case, asymmetric packaging stress could be generated and transferred to the die. The performance of MEMS devices, which employ the differential outputs of the sensing elements, is directly affected by the asymmetric packaging stress. In this paper, we proposed a die-attach structure with a pillar to reduce the asymmetric packaging stress and the changes in packaging stress due to changes in the device temperature. To verify the proposed structure, we fabricated four types of differential resonant accelerometers (DRA) with the silicon-on-glass process. We confirmed experimentally that the pillar can control the spreading of the adhesive and that the asymmetric packaging stress is considerably reduced. The simulation and experimental results indicated that the DRAs manufactured using glass-on-silicon wafers as handle substrates instead of conventional glass wafers have a structure that compensates for the thermal stress.
芯片粘贴是微机电系统（MEMS）器件制造中产生热应力的典型工艺。解决这个问题的一种方法是将部分芯片粘贴到封装上。在这种部分芯片粘贴中，对粘合剂扩散的控制不足会导致粘贴不均匀。在这种情况下，可能会产生非对称封装应力，并传递到芯片上。采用感测元件差分输出的 MEMS 器件的性能会受到非对称封装应力的直接影响。在本文中，我们提出了一种带有支柱的芯片粘贴结构，以减少非对称封装应力和由于器件温度变化引起的封装应力变化。为了验证所提出的结构，我们使用硅上玻璃工艺制造了四种差分谐振加速度计（DRA）。实验证实，支柱可以控制粘合剂的扩散，并且可以显著降低非对称封装应力。模拟和实验结果表明，使用玻璃上硅晶圆作为处理衬底而不是传统玻璃晶圆制造的 DRA 具有补偿热应力的结构。
