In this study, we evaluated the applicability of thin Au/Ti double-layered films as both bonding layers and gettering material for residual gases in micro-electromechanical system (MEMS) packaging. The thin Au/Ti films on Si substrates with thermal SiO₂ films were annealed at a maximum temperature of 400 °C for 1 h in atmospheric air to examine getter activation by the diffusion of Ti atoms to the surface through the Au film. X-ray photoelectron spectroscopy measurements revealed that the Ti atoms under the Au film diffused to the surface by the getter activation annealing at temperatures above 200 °C. The bonding characteristics of the thin Au/Ti films on the Si substrates were inspected through tensile tests, scanning acoustic microscopy (SAM), and transmission electron microscopy (TEM). With pre-bond annealing at or below 200 °C, no significant voids were observed at the bonding interfaces using SAM, and peeling was not observed at the bonding interface after the tensile tests. By contrast, the films could not bond with pre-bond annealing at 300 °C. At the bonding interface prepared after pre-bond annealing at or below 200 °C, no significant void was observed using cross-sectional TEM even after post-bond annealing at 300 °C, which is the required temperature for activation as a gettering layer. The results confirm that the thin Au/Ti films are applicable as both bonding layers and getter materials for MEMS packaging.

在这项研究中，我们评估了薄的Au / Ti双层薄膜作为微机电系统（MEMS）包装中残留气体的结合层和吸气材料的适用性。具有热SiO _2的Si衬底上的Au / Ti薄膜薄膜在大气中最高温度为400°C退火1小时，以研究通过Ti原子通过Au薄膜扩散到表面而引起的吸气剂活化。X射线光电子能谱测量表明，在200°C以上的温度下，通过吸气剂活化退火，金膜下的Ti原子扩散到表面。通过拉伸测试，扫描声显微镜（SAM）和透射电子显微镜（TEM）检查了Si衬底上Au / Ti薄膜的结合特性。在200°C或更低的温度下进行预粘结退火时，使用SAM在粘结界面上未观察到明显的空隙，并且在拉伸试验后，未在粘结界面上观察到剥离。相反，该膜不能在300°C的预粘结退火下粘结。在200℃或更低温度下进行预键合退火后制备的键合界面上，即使采用300°C的键合后退火（作为吸气层活化所需的温度），使用截面TEM也没有观察到明显的空隙。结果证实，Au / Ti薄膜可同时用作MEMS封装的粘结层和吸气材料。