圆片级气密封装及通孔垂直互连研究

提出了一种新颖的圆片级气密封装结构.其中芯片互连采用了通孔垂直互连技术:KOH腐蚀和DRIE相结合的薄硅晶片通孔刻蚀技术、由下向上铜电镀的通孔金属化技术、纯Sn焊料气密键合和凸点制备相结合的通孔互连技术.整个工艺过程与IC工艺相匹配,并在圆片级的基础上完成,可实现互连密度200/cm2的垂直通孔密度.该结构在降低封装成本,提高封装密度的同时可有效地保护MEMS器件不受损伤.实验还对结构的键合强度和气密性进行了研究.初步实验表明,该结构能够满足MIL-STD对封装结构气密性的要求,同时其焊层键合强度可达8MPa以上.本工作初步在工艺方面实现了该封装结构,为进一步的实用化研究奠定了基础.

Wafer-level hermetic package with through-wafer interconnects

A new wafer-level hermetic packaging structure for MEMS devices is reported by using through-wafer interconnects,which reduces the packaging cost,increases I/O densities in addition to the protection of the MEMS devices.Several wafer-level fabrication technologies were used in the structure fabrication process such as deep reactive ion etching(DRIE),KOH etching,bottom-up copper filling,Sn solder bonding and PbSn bump fabrication.This process is compatible with standard IC process and is finished at wafer level.The hermeticity and bonding strength of the structure is also evaluated.Preliminary results show that the hermeticity meets the requirement of the criterion of MIL-STD 883E,method 1014.9,and the bonding strength is up to 8MPa.The design,fabrication and characterization of this packaging structure,and the applicability in MEMS packaging were presented.