Chip-last FOWLP based antenna-in-package (FO-AiP) for 5G mmWave application

Abstract

5G wireless communication, there is two frequency bands: sub-6 (3.5GHz) and mmWave (26GHz, 28GHz and 39GHz). Although sub-6 frequency is mainly used in 5G wireless communication, the demand on mmWave of consumer is growing according to increasing the amount of data. However, systems operating at mmWave frequency range have to manage with much higher signal losses then in the sub-6 frequency range. Moreover, the physical size of interconnections (chip to chip, chip to antenna) becomes comparable to the operating wavelength. Therefore, new packaging technology is required corresponding the mmWave frequency range. Antenna integrated with RF chip using FOWLP technology has been developed for mmWave 5G application. The antenna and package structure of FO-AiP have been designed and simulated to obtain optimized performance. Besides, packaging process technologies have been developed to realize the designed FO-AiP structure. The FO-AiP is fabricated with array patch antenna for target frequency of 28GHz and package technology is similar to double molded FOWLP. Instead of 2nd mold compound, transparent low Dk/ Df insulation material has been adopted. The FO-AiP has been started in RDL first FOWLP on 300mm wafer size. The simulated single-patch antenna bandwidth under S11 ⩽ -10 dB was from 26.5 to 29.5 GHz and antenna gain of 7.5 dBi in the operating band. For 2 x 2 array antenna, antenna gain increased over 10 dBi while maintaining the 3GHz antenna bandwidth. The measurement results have a good agreement with the simulation. As a result, FO-AiP should be a promising technology for 5G mmWave system application.