Wang Junqiang, Zhang Haikun, Chen Xuwen, Li Mengwei
Academy for Advanced Interdisciplinary Research, North University of China, Taiyuan 030051, China.
Notional Key Laboratory of Instrumentation Science & Dynamic Measurement, North University of China, Taiyuan 030051, China.
Micromachines (Basel). 2022 Jul 28;13(8):1191. doi: 10.3390/mi13081191.
A chip-level hermetic package for a high-temperature graphene pressure sensor was investigated. The silicon cap, chip and substrate were stacked by Cu-Sn and Au-Au bonding to enable wide-range measurements while guaranteeing a high hermetic package. Prior to bonding, the sample was treated with Ar (5% H) plasma. The Cu-Sn bonding was firstly performed at 260 °C for 15 min with a pressure of 9.9 MPa, and the corresponding process conditions for Au-Au bonding has increased to 300 °C, 20 min and 19.8 MPa respectively. The average shearing strength was 14.3 MPa, and an excellent leak rate of 1.72 × 10 Pa·cm/s was also achieved. After high-temperature storage (HTS) at 350 °C for 10 h, the resistance of graphene decreased slightly because the dual bonding provided oxygen-free environment for graphene. The leakage rate of the device slightly increased to 2.1 × 10 Pa·cm/s, and the average shear strength just decreased to 13.5 MPa. Finally, under the pressure range of 0-100 MPa, the graphene pressure sensor exhibited a high average sensitivity of 3.11 Ω/MPa. In conclusion, the dual bonding that combined Cu-Sn and Au-Au is extremely suitable for hermetic packaging in high-temperature graphene pressure sensors.
研究了一种用于高温石墨烯压力传感器的芯片级气密封装。硅盖、芯片和基板通过铜锡和金金键合堆叠在一起，以实现宽量程测量，同时保证高气密性封装。键合前，样品用氩气（5%氢气）等离子体处理。铜锡键合首先在260℃下进行15分钟，压力为9.9兆帕，金金键合的相应工艺条件分别提高到300℃、20分钟和19.8兆帕。平均剪切强度为14.3兆帕，还实现了1.72×10帕·厘米/秒的优异泄漏率。在350℃下高温存储（HTS）10小时后，石墨烯的电阻略有下降，因为双重键合为石墨烯提供了无氧环境。器件的泄漏率略有增加至2.1×10帕·厘米/秒，平均剪切强度仅降至13.5兆帕。最后，在0-100兆帕的压力范围内，石墨烯压力传感器表现出3.11Ω/兆帕的高平均灵敏度。总之，铜锡和金金相结合的双重键合非常适合高温石墨烯压力传感器的气密封装。
