A Millimeter-Wave System-on-Package Technology Using a Thin-Film Substrate With a Flip-Chip Interconnection

In this paper, a system-on-package (SOP) technology using a thin-film substrate with a flip-chip interconnection has been developed for compact and high-performance millimeter-wave (mm-wave) modules. The thin-film substrate consists of Si-bumps, ground-bumps, and multilayer benzocyclobutene (BCB) films on a lossy silicon substrate. The lossy silicon substrate is not only a base plate of the thin-film substrate, but also suppresses the parasitic substrate mode excited in the thin-film substrate. Suppression of the substrate mode was verified with measurement results. The multilayer BCB films and the ground-bumps provide the thin-film substrate with high-performance integrated passives for the SOP capability. A broadband port terminator and a V-band broad-side coupler based on thin-film microstrip (TFMS) circuits were fabricated and characterized as mm-wave integrated passives. The Si-bumps dissipate the heat generated during the operation of flipped chips as well as provide mechanical support. The power dissipation capability of the Si-bumps was confirmed with an analysis of DC-IV characteristics of GaAs pseudomorphic high electron-mobility transistors (PHEMTs) and radio-frequency performances of a V-band power amplifier (PA). In addition, the flip-chip transition between a TFMS line on the thin-film substrate and a coplanar waveguide (CPW) line on a flipped chip was optimized with a compensation network, which consists of a high-impedance and low-impedance TFMS line and a removed ground technique. As an implementation example of the mm-wave SOP technology, a V-band power combining module (PCM) was developed on the thin-film substrate with the flip-chip interconnection. The V-band PCM incorporating two PAs with broadside couplers showed a combining efficiency higher than 78%.

[1]  J. Wenger,et al.  Automotive radar - status and perspectives , 2005, IEEE Compound Semiconductor Integrated Circuit Symposium, 2005. CSIC '05..

[2]  H. Zirath,et al.  Development of 60-GHz front-end circuits for a high-data-rate communication system , 2004, IEEE Journal of Solid-State Circuits.

[3]  Kristof Vaesen,et al.  Single-package integration of RF blocks for a 5 GHz WLAN application , 2001 .

[4]  Steven Brebels,et al.  Multilayer thin-film MCM-D for the integration of high-performance RF and microwave circuits , 2001 .

[5]  Kwang-Seok Seo,et al.  The flip-chip mounted mmic technology using the modified mcmd substrate for compact and low-cost w-band transceiver , 2005, IEEE MTT-S International Microwave Symposium Digest, 2005..

[6]  Nirod K. Das,et al.  Methods of suppression or avoidance of parallel-plate power leakage from conductor-backed transmission lines , 1996 .

[7]  J. S. Izadian,et al.  A new 6-18 GHz, -3 dB multisection hybrid coupler using asymmetric broadside, and edge coupled lines , 1989, IEEE MTT-S International Microwave Symposium Digest.

[8]  W. Heinrich,et al.  W-band flip-chip interconnects on thin-film substrate , 2002, 2002 IEEE MTT-S International Microwave Symposium Digest (Cat. No.02CH37278).

[9]  W. Heinrich,et al.  The flip-chip approach for millimeter wave packaging , 2005, IEEE Microwave Magazine.

[10]  Youngwoo Kwon,et al.  V-band high-efficiency broadband power combiner and power-combining module using double antipodal finline transitions , 2003 .

[11]  Sung-Jin Kim,et al.  Suppression of leakage resonance in coplanar MMIC packages using a Si sub-mount layer , 2000 .

[12]  H. Shigesawa,et al.  Conductor-backed slot line and coplanar waveguide: dangers and full-wave analyses , 1988, 1988., IEEE MTT-S International Microwave Symposium Digest.

[13]  Heeseok Lee,et al.  High-Performance Millimeter-Wave SOP Technology with Flip-Chip Interconnection , 2007, 2007 Proceedings 57th Electronic Components and Technology Conference.

[14]  Amir Mortazawi,et al.  A high-power Ka-band quasi-optical amplifier array , 2002 .

[15]  I. Gresham,et al.  A compact manufacturable 76-77-GHz radar module for commercial ACC applications , 2001 .