Shorting out bonding method for multi-stack anodic bonding and its application in wafer-level packaging

Abstract

Silicon/glass anodic bonding is widely investigated during MEMS packaging of multi-stack structures. The electrical behavior of anode bonding can be described as the charging and discharging process of RC circuit. Here, we conduct the equivalent RC circuit model analysis and experimental investigation, and demonstrate that voltage division and electricity leakage are the dilemma for the conventional multi-stack anodic bonding. By using feedthrough, the feasibility and convenience of “shorting out bonding” is presented, which is exampled through the wafer-level packaging of the MEMS gyroscope. Result from the sensor’s vacuum characterization reveals that shorting out bonding for multi-stack silicon/glass structures is an effective method for wafer-level packaging due to long-term stability and low temperature property.‘

Flexible anodic bonding for the bonding between elastomer and metal

“…The elements in bonding layer have been identified by the EDS analysis represented in Figure 8. Different elements including C, O, F, S, and Al are clearly identified in the bonding layers, showing that the process of anodic bonding has accompanied by the directional migration of ions driven by a certain temperature and electric fields 45–47 . It can be seen from the Figure 8b that the elements are less distributed in the intermediate bonding layer, which strongly supports our hypothesis about the ineffective bonding of CPEC2 and Al by traditional anodic bonding.…”