Glass Based 3D-IPD Integrated RF ASIC in WLCSP

As mobile and handheld devices become more functionalities, required to accommodate more frequency bands, and to meet small form factor requirements. IPD (Integrated Passive Device) offers small form factor, and high performance benefits for RF solutions. To achieve a high performance RF filters, high-Q inductor is a key factor. A possible best high-Q inductor can be achieved is by Glass based solenoid inductor. In addition, 3D IPD process is another approach to reduce package size and increase functionality. In this paper, the fabrication process of IPD, based on 8" glass wafer with Through Glass Via (TGV) to form the 3D solenoid inductor is presented. In addition, the process integration between wafer level, assembly, and double-sided process are addressed. Along the process integration, a RF ASIC is integrated through wafer level and assembly process to form the 3D integrated Wafer Level Chip Scale Package (WLCSP). The quality factor of 3D solenoid inductors can achieve Q of 70~100 in this study. The TGV and package reliability results are also discussed.