MEMS粘片工艺应力抑制技术

Stress Suppression Technology in MEMS Adhesive Die Attach Process

粘片工艺过程中产生的热机械应力是微电子机械系统(MEMS)芯片的主要误差源之一。为了降低粘片工艺应力对MEMS芯片的影响,提高MEMS芯片的稳定性,开展了MEMS粘片工艺应力抑制技术的研究。分析了胶体粘片工艺过程,通过解析模型进行应力来源的分析与计算;建立了有限元仿真模型,分析了MEMS芯片粘片过程中热机械应力的主要形成机理与分布情况;进行了相关工艺实验,得出了优化后的工艺方案,采用溢胶的点胶方式和杨氏模量较低的粘片胶是可抑制热机械应力的工艺方案,降低了粘片固化过程中的温度变化对MEMS芯片诱发的残余热机械应力,从而提高了MEMS芯片的稳定性。

The thermo-mechanical stress during the adhesive die attach process is one of the main error sources of micro-electromechanical system(MEMS) chips. To reduce the influence of the adhesive die attach process stress on the MEMS chip and improve the stability of the MEMS chip, the suppression technology of the MEMS adhesive die attach process stress was researched. The attach process of the adhesive die was analyzed, the stress sources were analyzed and calculated through analytical model. The finite element simulation model was established and used to analyze the main formation mechanism and distribution of the thermo-mechanical stress during the attach process of the MEMS die. The relative process experiment was carried out, and the optimized process scheme was obtained. The die attach of spilled glue method and the adhesive with lower Young’s modulus were used as the process scheme to suppress the thermo-mechanical stress. Then the residual thermo-mechanical stress induced by the temperature change in the curing process of the die attach on the MEMS chip was reduced, thereby improving the stability of the MEMS chip.