High Performance Chip-Partitioned Millimeter Wave Passive Devices on Smooth and Fine Pitch InFO RDL

Abstract

High performance millimeter wave passive devices are realized on smooth, fine pitch InFO redistribution layer (RDL). These passive devices are balun, power combiner, coupler, and microstrip line and the electrical performances are measured from 0.1GHz to 67 GHz through VNA. The measurement results show that the transmission loss of on-InFO balun (4.3 dB), the power divider (4.3 dB), and the coupler (4.9 dB) outperforms on-chip one by 2.1 dB, 1 dB, and 0.2 dB, respectively. While the transmission loss of microstrip line (0.34 dB/mm) is better than on-chip one by 0.17 dB/mm at 60 GHz. Furthermore, the parasitic of InFO chip-package interconnection has been investigated and compared to other technologies with and without solder bumps. The parasitic resistance, inductance, and capacitance for InFO interconnection are 75 %, 76 %, and 14 % lower than those for chip-last, face-down technology. Parasitic resistance for InFO RDL is 10 % lower than that for chip-first face-down technology with uneven RDL.