Advances in Science and Technology Vol. 81

Abstract: Recently various electronic control systems for automotive, industrial and consumer-electronic applications have been developed using advanced semiconductor technologies including MEMS sensors. This paper reviews the history of the development of the MEMS physical sensors and highlights their recent progress where their research trends are categorized into the following 4 items:ⅰ) Incorporation of heterogeneous sensors,ⅱ) Integration with advanced CMOS circuitry,ⅲ) Improvement on wafer-level packaging technology, ⅳ) Adoption of new materials. Several examples of each item are introduced in this paper.

Abstract: A novel fabrication process for large area flexible MEMS, having been developed in BEANS project, Japan, is introduced. The process consists of continuously high-speed coating for functional film materials, 3-D nano/micro-machining of the films on fibers, and weaving the functional fibers into large-area integration. In the coating process, functional materials, e.g., organic semiconductor, piezoelectric, conductor and insulator films could be formed on fibers with a speed of 20 m/min. In the 3-D nano/micro-machining, a compound reel-to-reel process system including both thermal roller imprint and photolithography functions was developed. In addition, the microfabrication of the 3-D exposure module and the spray deposition of thin resist films on the fibers were demonstrated. For the weaving assembly, a round-projection microspring contact structure was developed for the electrical contact between weft and warp fibers in a large area of woven textile. Evaluation of the durability showed that the microspring contact structures made of silicon elastomer and PEDOT:PSS are applicable to a movable contact. Weaving assembly process was verified by prototyping 1 × 1 m² or larger flexible touch sensor sheets using functional fibers with organic insulating/conductive films.

Abstract: We propose a novel bio-sensing platform based on the observation of the shift of the leaky surface plasmon mode that occurs at the edge of the plasmonic band gap of metal gratings based on two-dimensional gold nano-patch arrays when an analyte is deposited on the top of the metallic structure. We detail the numerical analysis, the fabrication and the characterization of these two-dimensional arrangements of gold patches in linear regime showing that sensitivity of our device approaches a value of 1000 nm/RIU with a corresponding Figure of Merit (FOM) of 222 RIU-1. We provide experimental proof of the sensing capabilities of the device by observing colour variations in the diffracted field when the air overlayer is replaced with a small quantity of Isopropyl Alcohol (IPA). Effects of technological tolerance such as rounded corners and surface imperfections are also discussed. We also report proof of changes in colour intensities as a function of the air/filling ratio ad periodicity and discuss how they can be obtained by diffracted spectra. Finally we report the numerical and experimental investigation of the non-linear behaviour of the device highlighting the Surface Enhanced Raman Scattering (SERS) performance.

Abstract: Here we present results from key aspects of our interest in using micromachined devices in the THz region. First, our early work on making filters from rods of gold-coated SU8 is described. Pass (up to 97%) and stop bands can be observed which are theoretically underpinned by both FDTD and complex band structure simulations. Second, there is a discussion of how THz radiation passes through two-dimensional periodic arrays of subwavelength apertures. In particular, the geometry of the arrays has been studied with time-domain spectroscopy. A time-of-flight model is presented which can be used to provide insight into the operation of these arrays and has implications for the optimum design of THz plasmonic sensors. Finally, we report the THz ‘super’ extraordinary transmission properties of an optimised hybrid subwavelength aperture array, surrounded by subwavelength grooves.

Abstract: A precisely rectilinear electrothermal actuator integrated with highly thermally expandable micromachined composites of SU-8 and silicon is presented. The actuator is capable of producing a maximum output rectilinear displacement of 42 μm with an estimated blocked force of up to 61 mN. The actuator operates at a low temperature rise of less than 266 °C and at input voltage of less than 15 V. Thermal time constant of the actuator is measured to be less than 3 ms. Such a powerful and power-efficient actuator could benefits future devices in optical MEMS.

Abstract: We investigated the wet-etching properties of SiCN films using chemical agents. Our results show that sodium hydroxide, potassium hydroxide and phosphoric acid etch SiCN films, while hydrochloric acid, sulfuric acid, acetic acid, ammonium chloride and sodium chloride cannot etch SiCN films.

Abstract: This paper gives an overview about problems of modeling of piezo-actuated stick-slip micro-drives. It has been found that existing prototypes of such devices have been investigated empirically. There is only few research dealing with the theory behind this kind of drives. By analyzing the current research activities in this field, it is believed that the model of the drive depends strongly on the friction models, but in most cases neglecting any influences of the guilding system.These analyses are of fundamental importance for an integrated model combining friction model and mechanical model offering promising possibilities for future research.

Abstract: With the increased prevalence of digital technologies in our everyday lives, the questions posed to the contemporary craft practitioner regarding creation of an emotionally resonant interaction between the digitally enhanced object and its wearer have become progressively more prominent in the applied arts. Through examining the notion that human biology is a part of material culture, where the body can be shaped, customised or altered through surgical intervention and scientific innovation, this extended abstract explores how recent developments in material science and wearable technologies can be viewed as contiguous rather than oppositional to the organic processes of the human body and how to bridge the gap between the craft practitioner and scientific discovery. More immediately however, this research project challenges the perception of smart materials and their application within the field of contemporary jewellery in both an artistic and scientific context through proposing the development of symbiotic stimulus-reactive jewellery organisms. Potential practical applications of these jewellery objects exist in the areas of human–computer interaction, transplant technology, identity management and artificial body modification including prosthetics, where such symbiotic jewellery organisms could be used to develop visually engaging yet multifunctional enhancements of the body.

Abstract: Technology called MEMS (Micro Electro Mechanical Systems) or microsystems are heterogeneous integration on silicon chips and play important roles as sensors. MEMS as switches and resonators fabricated on LSI are needed for future multi-band wireless systems. MEMS for safety systems as event driven tactile sensor network for nursing robot are developed. Wafer level packaging for MEMS and open collaboration to reduce the cost for the development are discussed.