Additively Manufactured mm-Wave Multichip Modules With Fully Printed "Smart" Encapsulation Structures

• Published in: IEEE transactions on microwave theory and techniques 2020-07, Vol.68 (7), p.2716-2724
• Main Authors: He, Xuanke, Tehrani, Bijan K., Bahr, Ryan, Su, Wenjing, Tentzeris, Manos M.
• Format: Article
• Language: English
• Subjects: 3-D printers; 3-D printing; Additive manufacturing; Amplification; Circuits; Electromagnetic compatibility; Electromagnetic interference; Encapsulation; Extremely high frequencies; frequency-selective surface (FSSs); Inkjet printing; Integrated circuit interconnections; Interconnections; interconnects; Low cost; Low noise; millimeter wave (mm-wave); Millimeter waves; monolithic microwave integrated circuit (MMIC); multichip module (MCM); Multichip modules; Noise levels; Production methods; Radio frequency; RF packaging; ribbon bonding; Substrates; Test vehicles; Three dimensional printing; Tooling
• ISSN: 0018-9480; 1557-9670
• DOI: 10.1109/TMTT.2019.2956934

This article presents the first time that an millimeter-wave (mm-wave) multichip module (MCM) with on-demand "smart" encapsulation has been fabricated utilizing additive manufacturing technologies. RF and dc interconnects were fabricated using inkjet printing, while the encapsulation was realized using 3-D printing. Inkjet-printed interconnects feature superior RF performance, better mechanical reliability, and on-demand, low-cost fabrication process. Numerous test vehicles were initially produced to evaluate these additive manufacturing technologies and compare them with traditional ribbon bonding, exhibiting a superior |\text{S}21| performance throughout the whole operation range up to 40 GHz with a peak of 3.3 dB better gain for a Ka-band low noise amplifier (LNA). A fully functioning front-end MCM was fabricated using the same inkjet-printed interconnect technology, which features smart encapsulation technology fabricated using the 3-D printing and integrated on-demand "smart" encapsulation for electromagnetic interference (EMI) mitigation. The proof-of-concept MCM demonstrates exceptional performance taking advantage of a low-cost, on-demand additive manufacturing method that requires minimal tooling and process steps, which can drastically accelerate the time to market for future 5G and Internet-of-Things applications. The methodologies presented in this article could potentially enable rapid production of high-performance, high-frequency customizable circuit packaging structures with on-demand "smart" features, such as self-diagnostics, EMI/EMC filtering, and integrated sensors.