77-GHz automotive radar sensor system with antenna integrated package

In this paper, a 3-D integrated 77-GHz automotive radar front-end is presented. Embedded wafer level packaging (EMWLP) technology is proposed to eliminate the use of wire bonding, which not only introduces significant radio frequency loss, but also occupies large footprint for high-pin count die. The transceiver bare die is embedded in a reconfigured molded wafer with compression molding process. Double-sided multiple redistribution layers are formed to fan-out the transceiver input/output signals and through mold via is employed to realize the vertical interconnection. With these promising features, the EMWLP technology can be extended to a 3-D integration. A substrate integrated waveguide slot antenna is integrated on top of the EMWLP module and a lens is used to enhance the antenna directivity. The performance of the fully integrated radar front-end is tested and the measurement results show good package performance with RF loss around 5 dB for most of the samples. Temperature cycling reliability test was also performed by letting the fully integrated prototype goes through 1000 temperature cycles with JEDEC standard. The measured package loss spread across samples after 1000 cycles of TC test is about 13 dB, which is mainly due to the antenna warpage affecting the RF path's signal integrity.