High-Q 3D-IPD Diplexer with High Aspect Ratio Cu Pillar Inductor

In this paper, a high quality factor 3D-inductor has been demonstrated by 3D-IPD solution with tall Cu pillar. It can achieve ~7:1 aspect ratio vertical connection without expensive TSV or TGV process, and meet the demand of high quality value wafer level process. A maximum quality factor of 60-80 has been achieved for 3D inductors in this study. Moreover, the proposed structure has been adopted to RF diplexer design with 1.0mm*0.5mm size for WiFi applications. The result shows a great performance improvement of lower insertion loss (0.31dB and 0.70dB) and larger attenuation (28dB and 26dB) than 2DIPD diplexer. Based on the measurement result, the proposed high aspect ratio tall Cu pillar technology has been verified on RF inductors and IPD diplexer, demonstrates good performance, and is a significant promise for commercial wireless radio system.