晶圆级封装对声表滤波器性能的影响

Influence of Wafer Level Packaging on SAW Filter Performance

声表器件表面换能器非常敏感,一旦污染将严重影响器件的性能。因此在实际使用过程中需要用特殊的封装方式对声表滤波器芯片加以保护。但是封装外壳的寄生参数（杂散）会对滤波器性能产生严重影响。该文通过电磁仿真软件（ADS-momentum）分析晶圆键合封装（WLP）对Band1双工器性能的影响。最大限度地降低封装对双工器的影响。仿真结果表明,不同的封装结构对滤波器的带外抑制和隔离度有极大影响。通过优化封装焊盘和封装材料设计,可提高带外抑制5-7dB。

Surface acoustic wave（SAW） devices are sensitive to surface contamination and therefore, their sur- faces are protected by using special packages. These packages could bring parasitic into the SAW filter that has an significant affect on its performance. In this work, we have designed a SAW duplexer implemented by using wafer level packaging（WLP）. The aim of this work was to minimize the parasitic influence caused by WLP packaging with ADS-momentum software. The simulation results suggested that differences in packaging design could have a signif- icant impact on the filter＇s isolation and rejection. A few modifications on the package＇s pads and layout could im- prove the filter＇s band rejections by 5-7 dB. In general, this work had provided the foundations for future works on WLP packaged SAW devices.