石墨烯压力传感器Au-Si共晶键合的气密性封装

Au-Si eutectic bonding of graphene pressure sensor for air-tight packaging

针对石墨烯压力传感器的高气密性封装要求,设计了一种应用于石墨烯压力传感器的Au-Si键合工艺。采用Au-Si键合工艺只需要在传感器的密封基板表面生长一层100 nm的SiO_(2),并在生长的SiO_(2)表面溅射金属密封环,密封环金属采用50 nm/300 nm的Ti/Au。使用倒装焊机在380℃以及16 kN的压力环境下保持20 min完成传感器芯片与基板的键合,实现石墨烯压力传感器的气密性封装。键合完成后对键合指标进行表征测试,平均剪切力可达19.596 MPa,平均泄露率为4.589×10^(-4) Pa·cm3/s。通过对键合前后石墨烯传感器芯片电阻检测,电阻输出平均值变化了3.36%,键合前后电阻输出相对稳定。对传感器进行静态压力检测,其灵敏度>0.3 kΩ/MPa,非线性<1%FS。实验结果表明,石墨烯压力传感器采用Au-Si键合工艺进行气密封装不仅工艺简单,且强度高。

In order to meet the requirement of high air tightness packaging of graphene pressure sensor,an Au-Si bonding process for graphene pressure sensor was designed.The Au-Si bonding process only needs to grow a layer of 100 nm SiO_(2) on the sealing substrate surface of the sensor,and a metal sealing ring was sputtered on the surface of the grown SiO_(2),which was made of 50 nm/300 nm Ti/Au.Then,a flip welding machine was used to bond the sensor chip to the substrate for 20 min at 380℃and 16 kN pressure environment to realize the air-tight packaging of the graphene pressure sensor.The average shear force can reach 19.596 MPa,and the average leakage rate is 4.589×10^(-4) Pa·cm^(3)/s.The resistance of graphene sensor chip was measured before and after bonding,and the average resistance output changed by 3.36%,indicating that the resistance output is relatively stable before and after bonding.The sensor was tested for static pressure with the sensitivity>0.3 kΩ/MPa and nonlinearity<1%FS.The experimental results show that the Au-Si bonding process is not only simple but also strong to encapsulate the graphene pressure sensor.