3 RF‑MEMS packaging by using quartz caps and epoxy polymers (original) (raw)

A reliable and compact polymer-based package for capacitive RF-MEMS switches

IEDM Technical Digest. IEEE International Electron Devices Meeting, 2004., 2004

We present a package for capacitive RF-MEMS switches that is based on laminate substrates and BCB-sealed glass caps. The assembly is done using standard packaging equipment. The package is only 1.1 mm thick, gross leak tight, has high mechanical strength, and passes accelerated lifetime testing. RF insertion loss was lower than 0.6 dB below 15 GHz. Capacitive switches packaged by the proposed method reach a lifetime of IO' cycles, and sustain 1000 h exposure at 85 "C / 85%RH.

A Stamp-Sealed Microshell Package for RF MEMS Switches

ASME 2007 InterPACK Conference, Volume 1, 2007

This paper describes a unique method of encapsulating MEMS switches at the wafer level using a thin-film "microshell" lid and a novel micro-embossing, or "stamping" technique to seal the lid. After fabrication of the MEMS switch and subsequent formation of the microshell, the switches are released through gold tunnels that allow the penetration of a chemical etchant. In a controlled ambient, a "stamp" wafer is aligned to the device wafer, and the wafers are thermally compressed together. This process applies pressure across each tunnel to fuse the gold, thereby sealing the microshell packages. By sealing and passivating the switches at the wafer level, the wafers can be exposed to backend processing, packaging, and assembly steps such as dicing without damaging the sensitive MEMS devices. Furthermore, the size, cost, and complexity of the packaged system are significantly reduced compared to standard wafer bonding processes.

RF–MEMS wafer-level packaging using through-wafer interconnect

Sensors and Actuators A: Physical, 2008

In this paper, development of a wafer-level packaging (WLP) process suitable for RF-MEMS applications is presented. The packaging concept is based on a high-resistivity silicon capping substrate that is wafer-level bonded to an RF-MEMS device wafer providing MEMS device protection and vertical electrical signal interconnect. The capping substrate contains Cu-plated through-wafer electrical vias and optional through-substrate cavities allowing for hybrid integration. The RF-MEMS device wafer and the capping substrate are bonded using either solder reflow or an electrically conductive adhesive. After solder bump formation and singulation, this packaging solution results in surface-mount technology compatible components. Moreover, the presented WLP solution allows hybrid integration of additional IC dies that are flip-chip bonded within the capping substrate cavities. joined as a PhD student the Centre for High Frequency Engineering, Cardiff University, UK, working in collaboration with Nokia. His research work covered large-signal time-domain measurement techniques at radio and microwave frequencies and nonlinear characterization and modelling of high-power high-frequency transistors such as silicon LDMOS FETs for telecommunication applications. From 2002 he is with the RF-IC design group at the was a post-doctoral fellow in the Electronic Instrumentation Laboratory, Delft University of Technology, dealing with research on technological aspects of integrated silicon sensor systems. Presently, he is with the Laboratory of High-Frequency Technology and Components (HiTeC), Delft University of Technology, as an assistant professor, working in the area of system integration and wafer-level packaging for RF applications.

Influence of 0-level packaging on the microwave performance of RF-MEMS devices

31st European Microwave Conference, 2001, 2001

are made of moveable and fragile structures (membranes, beams, cantilevers,…) that must be encapsulated for protection and for stable performance characteristics. Zerolevel or wafer-level packaging developed so far has been limited to dc-components. This paper elaborates on the design and fabrication of a 0-level package for housing RF-MEMS devices. The fabrication process is described and packages are characterized in terms of mechanical strength, hermeticity and microwave performance in the range 1-50 GHz. Simulations and experiments show minimal impact of the package on the RF losses if the cap has a minimal height of 50 µm, if low-loss materials (e.g., glass) are used, and if matched RF feedthroughs are implemented. Finally, in a multi-switch design, we recommend to minimize the number of feedthroughs, i.e. to use a single cap for the entire design.

Challenges of Radio Frequency MicroelectroMechanical Systems ( RF-MEMS ) 1

RF-MEMS (Radio Frequency-Micro Electro Mechanical Systems) are made up of moveable and fragile components (membranes, beams, cantilevers) that must be enclosed in for protection and for stable performance characteristics. Packaging is an important technology and critical aspect for the advancement of RF-MEMS. This paper elaborates the various RF-MEMS packaging challenges in the context of environment, modeling reliability, integration, stiction etc. All these challenges are application dependent; therefore case study on RF-MEMS switches with liquid crystal polymer (LCP) enclosure is presented for an in-depth illustration. RF-MEMS have the potential to have a tremendous impact on various fields such as wireless communication, defense, aerospace, radars, satellite etc. Packaging engineers are trying to overcome the packaging issues. They are trying to develop economical high-performance and highly reliable packaging solutions. The package plays a key role in ensuring the long term rel...

Parasitic effects reduction for wafer-level packaging of RF-MEMS

Arxiv preprint arXiv: …, 2007

In RF-MEMS packaging, next to the protection of movable structures, optimization of package electrical performance plays a very important role. In this work, a wafer-level packaging process has been investigated and optimized in order to minimize electrical parasitic effects. The package concept used is based on a wafer-level bonding of a capping silicon substrate with throughsubstrate interconnect to an RF-MEMS wafer. The capping silicon substrate resistivity, substrate thickness and the geometry of through-substrate electrical interconnect vias have been optimized using finiteelement electromagnetic simulations (Ansoft HFSS). Moreover, a preliminary analysis on the electromagnetic effects of the capping wafer bonding techniques (solder bump reflow and isotropic or anisotropic conductive adhesive [1]) is presented.

Packaging Challenges of Radio Frequency Microelectro-Mechanical Systems (RF-MEMS)

2011

RF-MEMS (Radio Frequency-Micro Electro Mechanical Systems) are made up of moveable and fragile components (membranes, beams, cantilevers) that must be enclosed in for protection and for stable performance characteristics. Packaging is an important technology and critical aspect for the advancement of RF-MEMS. This paper elaborates the various RF-MEMS packaging challenges in the context of environment, modeling reliability, integration, stiction etc. All these challenges are application dependent; therefore case study on RF-MEMS switches with liquid crystal polymer (LCP) enclosure is presented for an in-depth illustration. RF-MEMS have the potential to have a tremendous impact on various fields such as wireless communication, defense, aerospace, radars, satellite etc. Packaging engineers are trying to overcome the packaging issues. They are trying to develop economical high- performance and highly reliable packaging solutions. The package plays a key role in ensuring the long term re...

RF MEMS Switch Fabrication and Packaging

2020

RF (Radio Frequency) MEMS (Micro Electro Mechanical Systems) technology is the application of micromachined mechanical structures, controlled by electrical signals and interacting with signals in the RF range. The applications of these devices range from switching networks for satellite communication systems to high performance resonators and tuners. RF MEMS switches are the first and foremost MEMS devices designed for RF technology. A specialized method for fabricating microsturctures called surface micromachining process is used for fabricating the RF MEMS switches. Die level packaging using available surface mount style RF packages. The packaging process involved the design of RF feed throughs on the Alumina substrates to the die attachment, wire bonding and hermetic sealing using low temperature processes.

Novel Fabrication Tecniques for RF-MEMS Devices

MEMS parallel-plate capacitor structures are widely used in microelectromechanical systems (MEMS) as sensors, actuators, radiators, and optical system elements, among many other applications. However, the design and the fabrication process techniques are a very important aspect in the behavior and performance of MEMS devices. In this paper, we present a novel release technique for RF-MEMS, analyzing materials for high frequency applications with a high yield and avoiding stiction and structure collapse effects. The structures used in this work are MEMS capacitors.