This paper reports on a ZnO piezoelectric micro cantilever with a high-aspect-ratio (HAR) nano tip, which is proposed for a ferroelectric material based nano storage system. The system uses the interaction between the nano tip and a storage medium, and the HAR nano tip is needed to suppress undesirable effects caused by the small gap between the cantilever and the storage medium. The fabrication process for the cantilever with the HAR nano tip consists of three parts: the HAR nano tip formation, the cantilever fabrication, and the bonding/releasing process. The HAR nano tip is formed by the Si deep reactive ion etching for a long shaft and the anisotropic wet etching for a nano tip end. The cantilever is made up of 1 lm-thick LPCVD poly-Si layer and 0.2 lm-thick Si nitride layer, and has 0.5 lm-thick ZnO actuation layer. A final releasing process is followed by an anodic bonding process. The fabricated HAR nano tip has 6 lm side length, over 18 lm height, and less than 15 nm tip radius, which is built on the 85 lm-wide, 300 lm-long, and 1.2 lm-thick cantilever. The experimental results show a linear behavior with respect to input voltage of 1 to 5 V and the first resonance frequency at 17.9 kHz.
The morphology and fracture toughness of epoxy resins modified with amino-terminated polydimethylsiloxane (ATPDMS), differing in their molecular weight, and the degree of the preliminary reaction in the melt state were investigated. Tetramethyl biphenol diglycidyl ether (TMBPDGE) was used as the base epoxy resin. The degree of preliminary reaction between epoxy and polysiloxane increased with the decrease of the molecular weight of polysiloxane in the melt state. When the low molecular weight polysiloxane (AT900) was mixed with high molecular weight polysiloxane in the preliminary reaction, the low molecular weight polysiloxane enhanced the compatibility between the epoxy resin and the high molecular weight polysiloxane and produced smaller size and narrow distribution of polysiloxane particles. The small and highly concentrated polysiloxane particles, as determined by scanning electron microscopy improved the fracture toughness of the epoxy resin. ᭧ 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: [941][942][943][944][945][946][947][948][949][950][951][952][953][954][955] 1997
Although the groove and slot have been widely utilized for horn design to achieve high uniformity, their effects on uniformity have not been analyzed thoroughly. In this work, spool and bar horns for ultrasonic bonding are designed in a systematic way using the design of experiments (DOE) to achieve high amplitude uniformity of the horn. Three-dimensional modal analysis is conducted to predict the natural frequency, amplitude, and stress of the horns, and the DOE is employed to analyze the effects of the groove and slot on the amplitude uniformity. The design equations are formulated to determine the optimum dimensions of the groove and slot, and the uniformity is found to be influenced most significantly by the groove depth and slot width. Displacements of the spool and bar horns were measured using a laser Doppler vibrometer (LDV), and the predicted results are in good agreement with the experimental data.
We present a deep X-ray mask with integrated bent-beam electrothermal actuator for the fabrication of 3D microstructures with curved surface. The mask absorber is electroplated on the shuttle mass, which is supported by a pair of 20-lm-thick single crystal silicon bent-beam electrothermal actuators and oscillated in a rectilinear direction due to the thermal expansion of the bent-beams. The width of each bent-beam is 10 lm or 20 lm and the length and bending angle are 1 mm and 0.1 rad, respectively, and the shuttle mass size is 1 mm · 1 mm. For 10-lm-wide bent-beams, the shuttle mass displacement is around 15 lm at 180 mW (3.6 V) dc input power. For 20-lm-wide bent-beams, the shuttle mass displacement is around 19 lm at 336 mW (4.2 V) dc input power. Sinusoidal cross-sectional PMMA microstructures with a pitch of 40 lm and a height of 20 lm are fabricated by 0.5 Hz, 20-lm-amplitude sinusoidal shuttle mass oscillation.
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