Design, Fabrication, and Reliability of Low-Cost Flip-Chip-On-Board Package for Commercial Applications up to 50 GHz
Journal article, 2012

This paper presents a flip-chip-on-board (FCOB) packaging technology using a Rogers RO3210 laminate for microwave applications. Compared to the conventional microwave packaging architecture, the proposed FCOB technology skips one level of the ceramic package and thus results in lower reflections and manufacturing costs. To fulfill the small dimension requirement on printed circuit boards, the coplanar waveguide (CPW) transmission line and flip-chip bump were fabricated on a high-k RO3210 board (epsilon(r) = 10.2) with photolithography and electroplating. The GaAs chip patterned with the CPW line was then flip-chip-mounted onto the RO3210 laminate board. This structure displayed excellent performance from dc to 50 GHz with a return loss S-11 greater than 18 dB and insertion loss S-21 less than 0.5 dB. Meanwhile, the flip-chip bonding of the in-house-fabricated In0.52Al0.As-48/In0.6Ga0.4As metamorphic high-electron-mobility transistor devices on RO3210 also displayed excellent gain performance with a small degradation of 1 dB from dc to 40 GHz, showing the potential of implementing microwave integrated circuits on RO3210. To enhance the mechanical reliability, an epoxy-based underfill was injected into the flip-chip assemblies. Thermal cycling tests were performed to test the interconnect reliability, and the results indicated that the samples passed the thermal cycling test at least up to 600 cycles, showing excellent reliability for commercial applications. To the best of the authors' knowledge, this is the first study that evaluates the use of the RO3210 laminate for microwave flip-chip in open literature.

reliability

underfill

microwave

flip-chip-on-board

fabrication

Coplanar waveguide

metamorphic high-electron-mobility transistor device

interconnect

RO3210 laminate

packaging

Author

L. H. Hsu

National Chiao Tung University

C. W. Oh

National Chiao Tung University

W. C. Wu

National Chiao Tung University

E. Y. Chang

National Chiao Tung University

Herbert Zirath

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

C. T. Wang

National Chiao Tung University

S. P. Tsai

National Chiao Tung University

W. C. Lim

National Chiao Tung University

Y. C. Lin

National Chiao Tung University

IEEE Transactions on Components, Packaging and Manufacturing Technology

2156-3950 (ISSN) 21563985 (eISSN)

Vol. 2 3 402-409 6143996

Subject Categories

Materials Engineering

DOI

10.1109/TCPMT.2011.2171485

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4/5/2022 6