Li Wangwang, Liang Ting, Chen Yulei, Jia Pinggang, Xiong Jijun, Hong Yingping, Lei Cheng, Yao Zong, Qi Lei, Liu Wenyi
Science and Technology on Electronic Test & Measurement Laboratory, North University of China, Taiyuan 030051, China.
Key Laboratory of Instrumentation Science & Dynamic Measurement, Ministry of Education, North University of China,Taiyuan 030051, China.
Sensors (Basel). 2017 Sep 11;17(9):2080. doi: 10.3390/s17092080.
In this letter, we present a sapphire direct bonding method using plasma surface activation, hydrophilic pre-bonding, and high temperature annealing. Through the combination of sapphire inductively coupled plasma etching and the direct bonding process, a vacuum-sealed cavity employable for high temperature applications is achieved. Cross-sectional scanning electron microscopy (SEM) research of the bonding interface indicates that the two sapphire pieces are well bonded and the cavity structure stays intact. Moreover, the tensile testing shows that the bonding strength of the bonding interface is in excess of 7.2 MPa. The advantage of sapphire direct bonding is that it is free from the various problems caused by the mismatch in the coefficients of thermal expansion between different materials. Therefore, the bonded vacuum-sealed cavity can be potentially further developed into an all-sapphire pressure sensor for high temperature applications.
在本信函中，我们展示了一种利用等离子体表面活化、亲水性预键合和高温退火的蓝宝石直接键合方法。通过将蓝宝石电感耦合等离子体蚀刻与直接键合工艺相结合，实现了可用于高温应用的真空密封腔体。对键合界面的横截面扫描电子显微镜（SEM）研究表明，两个蓝宝石片键合良好，腔体结构保持完整。此外，拉伸测试表明键合界面的键合强度超过7.2 MPa。蓝宝石直接键合的优点是它不存在由不同材料之间热膨胀系数不匹配所引起的各种问题。因此，键合的真空密封腔体有可能进一步发展成为用于高温应用的全蓝宝石压力传感器。
