Packaging of RF MEMS switches and performance improvement

Download
2019
Comart, İlker
This dissertation presents a novel zero-level packaging method for shunt, capacitive contact RF MEMS switches where BCB acts as the adhesive interlayer between the cap and device wafers. Initially, the packaging concept is realized for 50 Ω CPW transmission lines. A microwave characterization procedure (circuit modeling) is performed by curve fitting five packaged CPW transmission line performances to the proposed circuit model. The circuit model consists of cascaded transmission line segments, in which lumped capacitances are utilized for modeling the discontinuities in the planar feedthrough regions. The microwave characterization procedure demonstrated 0.1 dB/transition with the implemented packaging approach. Afterward, shunt, capacitive contact RF MEMS switches are packaged by exactly the same package structure. Endurance analysis (shear strength tests), mechanical analysis (optical profiler measurements), actuation analysis (C-V measurements), RF performance analysis (S-parameter measurements), transient analysis (switching-time measurements), and lifetime analysis (lifetime measurements) assessed the overall performance of the BCB packaged RF MEMS switches. The packaging method demonvstrated 18.3 MPa average shear strength. One of the five tested switches reached 26.9 MPa, which exceeded the counterpart packaging methods in this regard. Optical profiler measurements of the MEMS bridge before and after the packaging process presented 71 nm average center deflection. Actuation analysis presented consistent results with the optical profiler measurements where the actuation voltages increased 4.2 V in the average during the packaging process. The S-parameter measurements indicated negligible effect on the RF performance of the switch. The return loss and insertion loss at 35 GHz (operating frequency) in the upstate are 28 dB and 0.4 dB, respectively. Moreover, the isolation characteristics indicate 35 dB at 35 GHz for most of the packaged switches. The transient analysis showed 10 µs rise time and 8.5 µs fall time for the packaged RF MEMS switches. Lifetime measurement demonstrates 10.2 billion cycles without failure in the RF performance. A sensitivity analysis based on EM simulations presented the robustness and insensitivity of the package in terms of possible process variations. The dissertation also presents a novel piecewise wideband characterization method based on CPW transmission line measurements to demonstrate the dispersive nature of the utilized glass and high-resistivity silicon wafers.

Suggestions

Development and Modeling of a Wafer-Level BCB Packaging Method for Capacitive RF MEMS Switches
Comart, Ilker; Cetintepe, Cagri; Sagiroglu, Ebru; Demir, Şimşek; Akın, Tayfun (2019-08-01)
This paper presents a novel wafer-level packaging method for shunt, capacitive RF MEMS switches using BCB as the adhesive interlayer. Fabrication and electrical characteristics of the proposed package were initially evaluated for 50 Omega CPW lines. Microwave measurements of these packaged test structures were fitted to a circuit model, which was later employed to optimize the package for RF MEMS switches. The proposed packaging method was next successfully integrated with an in-house RF MEMS fabrication pr...
Design of a MEMS based hydraulic pressure sensor
Göreke, Utku; Azgın, Kıvanç; Beyaz, Mustafa İlker; Department of Micro and Nanotechnology (2016)
This dissertation presents a novel technique for detection of hydraulic pressure by using a MEMS resonant sensor. Proposed sensor utilizes a double ended tuning fork (DETF) resonator. In the literature tuning forks are used for measurement of the deflection of a diaphragm. However, in this study, a tuning fork is configured to lay in orthogonal direction with a diaphragm of which center point deflection is being measured. Upon application of pressure, center deflection of the diaphragm induces an axial comp...
Reliability improvement of RF MEMS devices based on lifetime measurements
Gürbüz, Ozan Doğan; Demir, Şimşek; Akın, Tayfun; Department of Electrical and Electronics Engineering (2010)
This thesis presents fabrication of shunt, capacitive contact type RF MEMS switches which are designed according to given mm-wave performance specifications. The designed switches are modified for investigation in terms of reliability and lifetime. To observe the real-time performance of switches a time domain measurement setup is established and a CV (capacitance vs. voltage) curve measurement system is also included to measure CV curves, pull-in and hold-down voltages and the shifts of these due to actuat...
RF Telemetry Powering and Control of Hermetically-Sealed Integrated Sensors and Actuators
Akın, Tayfun; Najafi, Khalıl (2002-08-06)
An RF telemetry system for powering and control of microminiature integrated transducers packaged in a hermetically sealed custom-made glass capsule is described. A class-E power amplifier is utilized to energize and control a single-channel microstimulator for neuromuscular applications. The transmitter can deliver 1.5 W of power through a solenoid antenna using a 12-V rechargeable battery, while achieving efficiencies greater than 90%. The microstimulator antenna is a 1.5-mm-diameter, 4-5-mm-long ferrite-...
Modeling and fabrication of electrostatically actuated diaphragms for on-chip valving of MEMS-compatible microfluidic systems
Atik, Ali Can; Ozkan, Metin Dundar; Ozgur, Ebru; Külah, Haluk; Yıldırım, Ender (IOP Publishing, 2020-11-01)
This paper presents an analytical model to estimate the actuation potential of an electrostatic parylene-C diaphragm, processed on a glass wafer using standard microelectromechanical systems (MEMS) process technology, and integrable to polydimethylsiloxane (PDMS) based lab-on-a-chip systems to construct a normally-closed microvalve for flow manipulation. The accurate estimation of the pull-in voltage of the diaphragm is critical to preserve the feasibility of integration. Thus, we introduced an analytical m...
Citation Formats
İ. Comart, “Packaging of RF MEMS switches and performance improvement,” Thesis (Ph.D.) -- Graduate School of Natural and Applied Sciences. Electrical and Electronics Engineering., Middle East Technical University, 2019.