This paper presents the design, kinematics, fabrication and characterization of a monolithic micro positioning two degree-of-freedom translational (XY) stage. The design of the proposed MEMS (micro-electro-mechanical system) stage is based on a parallel kinematics mechanism (PKM). The stage is fabricated on a silicon-on-insulator (SOI) substrate. The PKM design decouples the motion in the XY directions. The design restricts rotations in the XY plane while allowing for an increased motion range and produces linear kinematics in the operating region (or workspace) of the stage. The truss-like structure of the PKM also results in increased stiffness by reducing the mass of the stage. The stage is fabricated on a silicon-on-insulator (SOI) wafer using surface micromachining and a deep reactive ion etching (DRIE) process. Two sets of electrostatic linear comb drives are used to actuate the stage mechanism in the X and Y directions. The fabricated stage provides a motion range of more than 15 µm in each direction at a driving voltage of 45 V. The resonant frequency of the stage under ambient conditions is 960 Hz. A high Q factor (∼100) is achieved from this parallel kinematics mechanism design.
Photonic microsystems played an essential role in the development of integrated photonic devices, thanks to their unique spatiotemporal control and spectral shaping capabilities. Similar capabilities to markedly control and manipulate X-ray radiation are highly desirable but practically impossible due to the massive size of the silicon single-crystal optics currently used. Here we show that micromechanical systems can be used as X-ray optics to create and preserve the spatial, temporal and spectral correlation of the X-rays. We demonstrate that, as X-ray reflective optics they can maintain the wavefront properties with nearly 100% reflectivity, and as a dynamic diffractive optics they can generate nanosecond time windows with over 100-kHz repetition rates. Since X-ray photonic microsystems can be easily incorporated into lab-based and next-generation synchrotron X-ray sources, they bring unprecedented design flexibility for future dynamic and miniature X-ray optics for focusing, wavefront manipulation, multicolour dispersion, and pulse slicing.
Nozzles with micro and nanometer scale orifices are playing an increasingly important role in many micro and nano devices, processes and characterization applications such as cell sorters, micro deposition of structures and near-field optical scanning. This paper describes a new process that can generate nozzles in a silicon substrate with nozzle walls of silicon nitride and oxide and with protudent geometry around the nozzle orifice. The fabrication process exploits a combination of geometry and differences in etching rates to simultaneously open up the nozzle orifice and pattern the geometry around it. The result is an in-parallel, high-throughput process.
We developed a novel piezo-driven parallel-kinematics single crystal silicon micropositioning XY stage. This monolithic design features parallelogram four-bar linkages, flexure hinges and piezoelectric stack actuators. The stage is made from single crystal silicon because it has excellent mechanical properties compared to metals, which result in high bandwidth, large work zone and compact size of the stage. Kinematics and dynamics analysis were performed for the design. We also developed microfabrication procedures to make the prototype of the stage. Experiment results show that the mechanical structure of the stage can deliver a 400µm by 400µm square work zone without failing any flexure hinges. With two piezoelectric stack actuators mounted, the stage is able to do open-loop contouring in a 32µm by 32µm work zone with 160V driving voltages applied. The resonation frequencies of the stage are between 1,300 and 1,400Hz.
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