Challenges and Solutions for Cost-effective RF-MEMS Packaging

Packaging poses a critical challenge for commercialization of MEMS (micro-electro-mechanical system) products. The packaging provides the critical structural and environmental protection necessary for fielding repeatable and reliable MEMS devices. For high volume markets such as mobile wireless terminals, where the technical benefits of RF-MEMS are highly attractive, the cost of effective packaging and assembly is a primary barrier to their adoption. RF-MEMS packaging is a nascent engineering field with widely varying approaches being explored to balance the broad range of technological and cost constraints. The cost of the packaging itself and all processing steps used to assemble the final product must be comparable to conventional packaging approaches used throughout the semiconductor industry. At the same time it must provide the necessary protection for the MEMS surfaces throughout the life of the product and not degrade the high RF performance provided by the MEMS. A key related aspect is additional functional integration enabled through MEMS that reduces the number of components required for a given application. In this paper, we describe the breadth of the RF-MEMS technologies and their associated packaging challenges. We follow with a range of implemented and proposed solutions to these challenges from both commercial and academic sources. Detailed comparisons in functionality, size and cost are drawn for a range of proposed metrics. We continue with solution recommendations for various functions and markets based on current technology and conclude with suggestions for future research and development.

[1]  S. Lee,et al.  3D stacked flip chip packaging with through silicon vias and copper plating or conductive adhesive filling , 2005, Proceedings Electronic Components and Technology, 2005. ECTC '05..

[2]  J. Schoebel,et al.  Integration of 0/1-Level Packaged RF-MEMS Devices on MCM-D at Millimeter-Wave Frequencies , 2005, IEEE Transactions on Advanced Packaging.

[3]  F. Barlow,et al.  Modeling-based design optimization of wafer-level and chip-scale packaging for RF-MEMS devices , 2005, Proceedings Electronic Components and Technology, 2005. ECTC '05..

[4]  E. Beyne,et al.  The indent reflow sealing (IRS) technique-a method for the fabrication of sealed cavities for MEMS devices , 2000, Journal of Microelectromechanical Systems.

[5]  A. Jourdain,et al.  Investigation of the hermeticity of BCB-sealed cavities for housing (RF-)MEMS devices , 2002, Technical Digest. MEMS 2002 IEEE International Conference. Fifteenth IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.02CH37266).

[6]  K. Najafi,et al.  Vacuum packaging technology using localized aluminum/silicon-to-glass bonding , 2002, Technical Digest. MEMS 2001. 14th IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.01CH37090).

[7]  Alan Mathewson,et al.  Performance and reliability of post-CMOS metal/oxide MEMS for RF application , 2003 .

[8]  Chong Ser Choong,et al.  A Vertical Wafer Level Packaging using Through Hole Filled Via Interconnects by Lift Off Polymer Method for MEMS and 3D Stacking Applications , 2005, Proceedings Electronic Components and Technology, 2005. ECTC '05..

[9]  Gabriel M. Rebeiz,et al.  Dc-50 GHz low-loss wafer-scale package for RF MEMS , 2004, 34th European Microwave Conference, 2004..

[10]  Byeong Kwon Ju,et al.  A novel low-loss wafer-level packaging of the RF-MEMS devices , 2002, Technical Digest. MEMS 2002 IEEE International Conference. Fifteenth IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.02CH37266).

[11]  Sonbol Massoud-Ansari,et al.  Chip-level vacuum packaging of micromachines using NanoGetters , 2003 .

[12]  K. Najafi,et al.  A low-temperature thin-film electroplated metal vacuum package , 2004, Journal of Microelectromechanical Systems.

[13]  M. Fujii,et al.  RF MEMS Switch with Wafer Level Package Utilizing Frit Glass Bonding , 2002, 2002 32nd European Microwave Conference.

[14]  Qian Wang,et al.  A low temperature, hermetic wafer level packaging method for RF MEMS switch , 2005, Proceedings Electronic Components and Technology, 2005. ECTC '05..

[15]  David I. Forehand,et al.  Wafer Level Micropackaging for RF MEMS Switches , 2005 .

[16]  David W. Peterson,et al.  MEMS Packaging - Current Issues and Approaches , 2000 .

[17]  Qian Wang,et al.  Application of Au-Sn eutectic bonding in hermetic RF MEMS wafer level packaging , 2004, 9th International Symposium on Advanced Packaging Materials: Processes, Properties and Interfaces (IEEE Cat. No.04TH8742). 2004 Proceedings..

[18]  M. Iyer,et al.  Design and electrical characterization of a novel wafer level package for RF MEMS applications , 2003, 53rd Electronic Components and Technology Conference, 2003. Proceedings..

[19]  Thomas W. Kenny,et al.  Single wafer encapsulation of MEMS devices , 2003 .

[20]  S. M. Spearing,et al.  Fabrication of wafer-level thermocompression bonds , 2002 .

[21]  K. Boustedt,et al.  Fundamental requirements on MEMS packaging and reliability , 2002, 2002 Proceedings. 8th International Advanced Packaging Materials Symposium (Cat. No.02TH8617).

[22]  L.P.B. Katehi,et al.  High frequency parasitic effects for on-wafer packaging of RF MEMS switches , 2003, IEEE MTT-S International Microwave Symposium Digest, 2003.

[23]  R. Howe,et al.  Microelectromechanical filters for signal processing , 1992, [1992] Proceedings IEEE Micro Electro Mechanical Systems.

[24]  T. Marinis,et al.  Wafer level vacuum packaging of MEMS sensors , 2005, Proceedings Electronic Components and Technology, 2005. ECTC '05..