Design and Implementation of RF Front-End Module Based on 3D Heterogenous-Integrated Wafer-Level Packaging

Abstract

In this paper, a three-dimensional heterogenous-integrated (3DHI) wafer-level packaging (WLP) process is proposed, and a radio frequency (RF) front-end module with two independent ultra-high frequency (UHF) receiving channels are designed and implemented, which covers 400 MHz–600 MHz and 2050 MHz–2200 MHz respectively for unmanned aerial vehicle (UAV) applications. The module is formed by wafer-to-wafer (W2W) bonding of two high-resistivity silicon (HR-Si) interposers with embedded bare dies and through silicon via (TSV) interconnections. Double-sided deep reactive ion etching (DRIE) and conformal electroplating process are introduced to realize the high-aspect-ratio TSV connection within 290 µm-thick cap interposer. Co-plane waveguide (CPW) transmission lines are fabricated as the process control monitor (PCM), the measured insertion loss of which is less than 0.18 dB/mm at 35 GHz. The designed RF front-end module is fabricated and measured. The measured return loss and gain of each RF channel is better than 13 dB and 21 dB, and the noise figure is less than 1.5 dB. In order to evaluate the capability of the 3DHI process for multi-layer interposers, the module is re-designed and fabricated with four stacked high-resistivity silicon interposers. After W2W bonding of two pairs of interposers and wafer slicing, chip-to chip (C2C) bonding is applied to form a four-layer module with operable temperature gradient.

3D Heterogenous Integrated Wideband Switchable Bandpass Filter Bank for Millimeter Wave Applications

“…When the front-side processing of the interposer wafers is completed, temporary adhesive bonding is used to affix a support wafer. In the following fabrication steps, the same procedure is used to treat the opposite surface [22].…”

A compact 2-18GHz ultra-wideband frequency-conversion T/R module based on a 3D heterogeneous integrated process

“…However, these designs still employ a two-dimensional (2D) multichip module (MCM) package, the minimum sizes of which are limited by the sizes of the applied chips. To address this issue, an increasing number of researchers are employing three-dimensional (3D) packaging to achieve high integration of frequency-conversion modules and T/R modules [21][22][23][24][25][26], aiming to break the chip size limit with chip stacking in the third dimension.…”