Wafer-Level Parylene Packaging With Integrated RF Electronics for Wireless Retinal Prostheses

This paper presents an embedded chip integration technology that incorporates silicon housings and flexible Parylene-based microelectromechanical systems (MEMS) devices. Accelerated-lifetime soak testing is performed in saline at elevated temperatures to study the packaging performance of Parylene C thin films. Experimental results show that the silicon chip under test is well protected by Parylene, and the lifetime of Parylenecoated metal at body temperature (37°C) is more than 60 years, indicating that Parylene C is an excellent structural and packaging material for biomedical applications. To demonstrate the proposed packaging technology, a flexible MEMS radio-frequency (RF) coil has been integrated with an RF identification (RFID) circuit die. The coil has an inductance of 16 μH with two layers of metal completely encapsulated in Parylene C, which is microfabricated using a Parylene–metal–Parylene thin-film technology. The chip is a commercially available read-only RFID chip with a typical operating frequency of 125 kHz. The functionality of the embedded chip has been tested using an RFID reader module in both air and saline, demonstrating successful power and data transmission through the MEMS coil

Monolayer MoS2 strained to 1.3% with a microelectromechanical system

We report on a modified transfer technique for atomically thin materials integrated onto microelectromechanical systems (MEMS) for studying strain physics and creating strain-based devices. Our method tolerates the non-planar structures and fragility of MEMS, while still providing precise positioning and crack free transfer of flakes. Further, our method used the transfer polymer to anchor the 2D crystal to the MEMS, which reduces the fabrication time, increases the yield, and allowed us to exploit the strong mechanical coupling between 2D crystal and polymer to strain the atomically thin system. We successfully strained single atomic layers of molybdenum disulfide (MoS2) with MEMS devices for the first time and achieved greater than 1.3% strain, marking a major milestone for incorporating 2D materials with MEMS We used the established strain response of MoS2 Raman and Photoluminescence spectra to deduce the strain in our crystals and provide a consistency check. We found good comparison between our experiment and literature.Published versio

Performance of RF MEMS switches at low temperatures

The actuation voltage of microelectromechanical system (MEMS) \ud metal switches was investigated at temperatures ranging from 10 to 290 K. The investigation shows a 50% increase in the actuation voltage at low temperature. A comparison has been made using a published model and showed similar increment of actuation voltage at low temperature

Damage identification in structural health monitoring: a brief review from its implementation to the Use of data-driven applications

The damage identification process provides relevant information about the current state of a structure under inspection, and it can be approached from two different points of view. The first approach uses data-driven algorithms, which are usually associated with the collection of data using sensors. Data are subsequently processed and analyzed. The second approach uses models to analyze information about the structure. In the latter case, the overall performance of the approach is associated with the accuracy of the model and the information that is used to define it. Although both approaches are widely used, data-driven algorithms are preferred in most cases because they afford the ability to analyze data acquired from sensors and to provide a real-time solution for decision making; however, these approaches involve high-performance processors due to the high computational cost. As a contribution to the researchers working with data-driven algorithms and applications, this work presents a brief review of data-driven algorithms for damage identification in structural health-monitoring applications. This review covers damage detection, localization, classification, extension, and prognosis, as well as the development of smart structures. The literature is systematically reviewed according to the natural steps of a structural health-monitoring system. This review also includes information on the types of sensors used as well as on the development of data-driven algorithms for damage identification.Peer ReviewedPostprint (published version

Flip-chip distributed MEMS transmission lines (DMTLs) for biosensing applications

Design and characterization of a flip-chip distributed MEMS transmission line (DMTL) are presented. The concept of using this DMTL as a biosensor is then introduced. Radio frequency experiments on the DMTL loaded with biosamples have been conducted using the most accessible materials, namely, deionized water and aqueous solutions of salts. Results show that the reflection coefficient (S11) of the solution-loaded DMTL is very sensitive to the salt concentration of the solution in the low-frequency ranges of 10 MHz-1 GHz and 3-4.5 GHz. At high frequencies, the relative dielectric constant of the biosample can also be quantitatively determined from the impedance of the DMTL

A microwave dielectric biosensor based on suspended distributed MEMS transmission lines

Design and characterization of a miniature microwave dielectric biosensor based on distributed microelectromechanical systems (MEMS) transmission lines (DMTL) is reported in this paper. The biosensor has been realized by bonding the DMTL device with an acrylic fluidic channel. In order to demonstrate the sensing mechanism, the sensor is used to detect the small variation of the concentration of aqueous glucose solutions by measuring the electromagnetic resonant frequency shift of the device. It is observed from the results that the second notch of the reflection coefficient (S-11) varies from 7.66 to 7.93 GHz and the third notch of the reflection coefficient varies from 15.81 to 15.24 GHz when the concentration of the glucose solution ranges from 0 to 347 mg/ml, which indicates that higher order notches have higher sensitivities if looking at the absolute change in frequency

Introducing The Small World: Developing The Mems/Nanotechnology Curriculum

© ASEE 2009MEMS (Microelectromechanical Systems) and nanotechnology are believed to be the exciting drive to trigger the next wave of technology revolution. MEMS refer to systems in micro scale (1 micron to 1 millimeter) that integrates mechanical components, sensors, actuators, and electronics on a common silicon substrate through micromachining technology. Due to its low cost, small size, light weight and high resolution, MEMS has been widely used in automobiles, medical health care, aerospace, consumer products and RF communications. Nanotechnology refers to a field of applied science and technology about materials and devices in the atomic and molecular scale, normally 1 to 100 nanometers. It can offer better built, longer lasting, cleanser, safer and smarter products for home, communications, medicine, transportation, agriculture and many other fields. MEMS and nanotechnology can be combined to create a new exciting field of NEMS (Nanoelectromechanical system). In order to introduce engineering students into this amazing micro and nanotechnology field, we developed three corresponding graduate-level courses: Introduction to MEMS (EE446) and Introduction to Nanotechnology (EE451), and Microelectronic Fabrication (EE448). In addition, we have other related courses to support this program, such as EE 447: Semiconductor, EE 404: CMOS VLSI, EE 410: Bio-sensors, etc. This paper will discuss the course structure, syllabuses, course modules, student feedbacks, as well as future plans for this program. This curriculum offer students comprehensive knowledge and experience in MEMS and nanotechnology. Students use various CAD tools such as ANSYS FEM to design and simulate various MEMS/NEMS devices in the course projects. Multimedia technology is also used during the classroom teaching. We played vivid photos/videos to show the operation of MEMS/NEMS devices and state-of-the-art micro/nano fabrication processes in industry. Students demonstrated tremendous interest in this micro/nanotechnology program. The enrollment to these courses has been overwhelming and we have to create extra sessions to accommodate students with strong interest in this program. Our graduated students are well prepared for the industry in micro/nanotechnology fields. This program can also be helpful for the effort of the Connecticut Nanotechnology Curriculum Committee

Microelectromechanical Scanner Using a Vertical Cavity Surface Emitting Laser

Optical scanners play a prominent role in the commercial and military industries. The scanner\u27s size, cost and reliability are critical characteristics. In this research a microoptical scanning system was fabricated by incorporating a vertical cavity surface emitting laser (VCSEL) onto a surface machined microelectromechanical die. The micro optics for laser beam steering includes a 135 deg mirror, a Fresnel lens, a lateral scanning rotating mirror, and a vertical scanning fan mirror. The VCSEL was attached to the die by solder and electrical connection was provided by wire bonding. Based on far field measurements the scanner had a lateral scan angle of 5.7 degrees and a vertical scan angle of 4.4 degrees. Based on spot diameter measurements at the fan mirror the scanner had a divergence angle of 0.524 degrees. The potential military applications of these scanners include laser radars, laser detectors, holographic storage devices, and data links between integrated circuit chips

Radio Frequency Microelectromechanical Systems in Defence and Aerospace

For all onboard systems applications, it is important to have very low-loss characteristics and low power consumption coupled with size reduction. The controls and instrumentation in defence and aerospace continually calls for newer technologies and developments. One such technology showing remarkable potential over the years is radio frequency microelectromechanical systems (RF MEMS) which have already made their presence felt prominently by offering replacement in radar and communication systems with high quality factors and precise tunability. The RF MEMS components have emerged as potential candidates for defence and aerospace applications. The core theme of this paper is to drive home the fact that the limitations faced by the current RF devices can be overcome by the flexibility and better device performance characteristics of RF MEMS components, which ultimately propagate the device level benefits to the final system to attain the unprecedented levels of performance.Defence Science Journal, 2009, 59(6), pp.568-567, DOI:http://dx.doi.org/10.14429/dsj.59.156

Dynamics simulation of microelectromechanical electrostatic actuator incorporating the squeeze-film damping effect

In this study, the influences of the squeeze-film damping effect on the dynamic behavior of the microelectromechanical electrostatic actuators are investigated by the hybrid numerical scheme comprising the differential transformation method and the finite difference method. There are two types of actuators which including the circular micro-plate and the clamped-clamped micro-beam, relatively. The analyses take account of the axial stress effect, the residual stress and the fringing field effect within the micro actuators and explore the dynamic response of the plate/beam as a function of the magnitude of the AC driving voltage. The effectiveness of a combined DC/AC loading scheme in driving the micro actuators are examined. It is shown that the use of an AC actuating voltage in addition to the DC driving voltage provides an effective means of tuning the dynamic response of the micro actuators. Therefore, the results show that the hybrid method provides an accurate and computationally-efficient means of analyzing the nonlinear behavior of the micro-beam structures used in many of today’s MEMS-based actuator systems