Padraig L. Fitzgerald

Fully integrated, high yielding, high reliability DC contact MEMS switch technology & control IC in standard plastic packages

In this paper we present a fully integrated, high yielding, high reliability DC contact microelectromechanical systems (MEMS) switch technology. A high voltage double-diffused metal-oxide-semiconductor (DMOS) driver application-specific integrated circuit (ASIC) is co-packaged with a single-pole-four-throw (SP4T) DC contact MEMS switch in a 5×4×1mm 24-pin quad flat no leads (QFN) plastic package. The MEMS switch process yields >90% on 6 inch wafers and plastic package devices have been subjected to standard IC qualification testing as well as MEMS switch specific lifetime testing over −40°C to 85°C with industry leading results. The MEMS switch is actuated with 80V generated by the control ASIC and exhibits cycle lifetime of > 3 Billion (3×109) cycles when toggled at 5 kHz. The switches are targeted at radio frequency (RF) switching applications and have insertion loss/isolation of 0.4dB/25dB at 6 GHz. Key challenges overcome were, design of the MEMS switch to ensure high yield and reliability, low thermal sensitivity under the influence of the packaging process, optimization of the contact system, and design of the actuation waveform to enhance lifetime.

Commercialization of a reliable RF MEMS switch with integrated driver circuitry in a miniature QFN package for RF instrumentation applications

This paper describes the commercialization of a reliable RF single pole four throw (SP4T) micro-electromechanical systems (MEMS) switch with integrated driver circuitry which is targeted at RF instrumentation applications. The integrated switch solution is mass produced in a high volume sub-micron semiconductor Class1 clean room manufacturing facility, fabricated on a low loss substrate and utilizes a wafer level silicon capping technology. This device achieves a low insertion loss of 0.52dB typical at 6GHz, a wide -3dB RF bandwidth of 11GHz to 14GHz and a minimum actuation lifetime of 1 billion cycles; and is presented in a small 5mm × 4mm × 0.95mm 24-pin quad flat no leads (QFN) plastic package. Topics discussed in the paper include the motivation for the development, fabrication, long term reliability and switch characteristics.

Model-based analysis of switch degradation effects during lifetime testing

The paper reports on the transient analysis of the observed decrease in the actuation voltage of MEMS ohmic switches, under a stress condition. A finite difference model (FDM) is developed that provides insight into the contributions of various mechanical factors to the measured changes in switch performance. In particular, the proposed method allows us to investigate the effects of spring constant reduction and plastic deformation of the switch. Such an analysis cannot be done on the basis of an empirical fitting or existing analytical models. The presented method can be used in the lifetime evaluation of the switch and this application is demonstrated.

Continuous dynamic timing measurements to monitor spring and surface forces in MEMS switch reliability

In this work we demonstrate an automatic reliability detection/prediction system for industry manufactured ohmic MEMS switches based on dynamic time measurements. The developed method allows for constant device monitoring and highlights the influence of both restoring and surface forces evolution on switch reliability. Also for the first time it allows for an identification of an imminent device failure due to its continuous monitoring. We present the scalability of this approach by testing it on six different, industry-manufactured switch types and on a large number of samples.

Intrinsic reliability characterization for stand-alone MEMS switch technology

This work presents a device level reliability (DLR) characterization for the Analog Devices proprietary metal contact microelectromechanical systems (MEMS) switch technology. Stand-alone device characterizations in both hold-down and toggle operation modes are described. An alternative operation mode to analyze is the so called “hot switching”. The switch pull-in voltage and the contact resistance are the main physical parameters that have been analyzed. This DLR characterization methodology can be considered a first step towards a standard that will be performed in parallel to typical product qualifications in order to assess the device long term reliability.