A Ka-band BCB based Back-to-Back BGA Transition for 3D Heterogeneous Integration

This paper presents a Ka-band back-to-back BGA transition for the 3D heterogeneous integration based on BCB. Impedance matching structures are designed to compensate for the discontinuities caused by BGA. The transition is fabricated by the silicon-based MEMS photosensitive composite-film process. The simulated and measured results show that the transition has a 15 dB impedance bandwidth from 26 GHz to 40 GHz, and its insert loss values better than 1.5 dB up to 36 GHz per pass through one BGA transition.