Miniaturized Millimeter-Wave Hybrid IC Technology Using Non-Photosensitive Multi-Layered BCB Thin Films and Stud Bump Bonding

Hiroshi OGURA
Morikazu SAGAWA

IEICE TRANSACTIONS on Electronics   Vol.E82-C    No.11    pp.2029-2037
Publication Date: 1999/11/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section INVITED PAPER (Special Issue on High-Frequency/High-Speed Devices for Information and Communication Systems in the 21st Century)
Category: RF Assembly Technology
millimeter wave,  flip-chip bonding,  stud bump,  micro bump,  BCB,  multi-layer,  

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This paper describes a new millimeter-wave hybrid integrated circuit (HIC) technology which applies a thin film multi-layered dielectric substrate and flip-chip bonding technology employing stud bump bonding (SBB). We have previously proposed and demonstrated a novel HIC structure, named millimeter-wave flip-chip IC, (MFIC), applying an excellent dielectric material of benzocyclobutene (BCB) thin film and flip-chip bonding. In this paper, an advanced thin film multi-layer process using non-photosensitive BCB was newly developed. Characteristics of the transmission lines and the built-in MIM capacitor within the multi-layered structure were discussed. Furthermore, stud bump bonding was newly adapted to the MFIC as a flip-chip method, and the millimeter-wave characteristics of the bumps were examined. Using these technologies, we demonstrate characteristics of a miniaturized 25 GHz down converter MFIC. Our newly proposed HIC structure enabled us to bring down chip size to less than 1/3 of our conventional structure. Finally, we discuss future possibilities for high performance multi-chip-modules (MCMs) using SBB technology as a further improved HIC for compact millimeter-wave radio equipment.