Additive Manufacturing of a W-Band System-on-Package

Abstract

In this article, we demonstrate the design, fabrication, and characterization of a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$W$ </tex-math></inline-formula> -band system-on-package (SoP). This package is fully additively manufactured using a chip-first process and aerosol jet printing. With this method, we implement a transceiver consisting of two bare die amplifiers for transmitted and received signals, a bare die switch, printed bypass capacitors, surface-mount resistors for biasing networks, and a printed patch antenna, operating between 77.1 and 79.0 GHz. The second patch antenna of the same design, fabricated simultaneously, is used to characterize the antenna performance alone and the packaged components. Package substrates (dielectrics), conductors, and interconnects are printed around bare die attached to a carrier. Thin-film bypass capacitor dielectrics were printed using multimaterial aerosol jet printing (MMAJP), where aerosols of barium titanate and polyimide inks are mixed in place to form a high <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\epsilon _{r}$ </tex-math></inline-formula> polymer matrix nanocomposite film. <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$W$ </tex-math></inline-formula> -band interconnect performance is achieved using conformal-shaped ramp interconnects, allowing for frequency agnostic performance of the interconnect with no impedance discontinuity, within the physical limits of the printer. The antenna alone achieves a maximum gain of 6.7 dBi at 78.3 GHz, and the SoP achieves a gain of 16.4 dBi for the package. We estimate the package loss to be 2.8 dB or 0.6 dB/mm, including interconnects.