Precise micromachining of yttria-tetragonal zirconia polycrystal ceramic using 532 nm nanosecond laser

High quality micro-sized steps and blind hole structures without microcracks, chips or spatter deposition were machined on yttria-tetragonal zirconia polycrystal (Y-TZP, 3 mol% yttria) by nanosecond laser (wavelength=532 nm, pulse width ~6 ns). The diameter of blind hole is 500 μm and each step is 500±10 μm wide and 100±5 μm deep. The 1.35 mm³/min removal rate and the smooth machined surface with Ra=2.824 μm roughness depicting the high precise and efficient processing were achieved. The ablation characteristics of nanosecond laser process of Y-TZP ceramic were also studied. Based on the study, a reasonable design of the processing path for micromachining of a finer embedded step with 24±2 μm width (smaller than the 60 μm focused spot size) around the inner-wall of a 2×2 mm² cavity was developed. These results and discussion offer new possibilities in the manufacturing of bio-ceramic products by nanosecond laser with high processing quality and efficient.     

Miniaturized continuous-flow polymerase chain reaction microfluidic chip system

A miniaturized continuous-flow polymerase chain reaction (PCR) microfluidic chip system was developed to perform DNA amplification. This system consists of a 20-cycle continuous-flow PCR microfluidic chip, an electrical heating system and a miniature air pressure-vacuum pump. The chip was ablated with excimer laser direct-writing micromachining technique on a polymethyl methacrylate (PMMA) sheet. The ablated microchannel was inverse trapezoidal with a depth of 70 μm, top width of 200 μm and bottom width of 120 μm. Its surface roughness Ra was 1.42 μm after being treated with excimer laser polishing. The substrate sheet ablated with the microchannel was bonded with other cover sheets using hot-press bonding method to form a closed structure. The electrical heating system consisted of three groups of heating membranes, Pt100 sensors, copper blocks and PID temperature digital controllers. It could provide three distinct maintained temperature zones and a uniform temperature distribution in each zone. PCR amplification of a 170 base pair (bp) DNA fragment was carried out to validate the system's feasibility. The PCR temperatures were set as 94℃ for denaturation, 55℃ for primer annealing and 72℃ for extension. The flow rate in the microchannel was 40 nL/s and the total time for the completion of a 20-cycle amplification of 20 μL reagent was 15 min.     

Laser-based sample preparation for high-resolution X-ray-computed tomography of glasses and glass ceramics

X-ray-computed tomography with sub-micron resolution (nano-CT) is one of the most useful techniques to examine the 3D microstructure of materials down to voxel sizes 10 nm. However, since size and shape of samples have considerable influence on acquisition time and data quality, adapted and universally applicable workflows are needed. Three novel workflows for sample preparation using ultra-short pulsed lasers are presented which allow for reproducible fabrication, safe extraction and mounting of samples. Their application potential is illustrated via nano-CT measurements of glass ceramics as well as a laser-modified glass. Since the according sample geometries take also the requirements of other analytical techniques such as transmission electron microscopy into account, samples prepared according to the new workflows can be furthermore seen as a starting point for correlative microstructural analyses involving multiple techniques.     

复合静电驱动结构致动的内旋转微镜

报道了以体硅表面硅混合微加工工艺制作在SOI衬底上的一种新型复合静电驱动结构致动内旋转微镜,其中复合静电驱动结构由一个平板驱动器和一个垂直梳齿驱动器构成.实验表明,该新型驱动结构不仅能使微镜实现大范围连续旋转,而且能使微镜实现吸合效应致自发性90°旋转.微镜的连续旋转范围扩大到约46°,同时引发吸合效应的拐点电压也增大.对于具有1和0.5μm厚扭转弹性梁的微镜,实测拐点电压分别为390～410V和140～160V.当该微镜用作光开关时,测得光插入损耗为～1.98dB.     

微三维结构电火花铣削关键技术研究

为解决电火花方法加工微三维结构时工具电极的制备、测量和损耗补偿问题,研究了块反拷法和线电极磨削法(WEDG)相配合的电极加工工艺,设计了通过4点接触感知实现的电极在线测量系统,提出了由数控系统对放电状态进行实时监测、统计并根据统计结果预测电极损耗状况的自动补偿策略。此技术方案在计算电极加工路径时无需作任何补偿考虑,因此可选用普通金属铣削CAM软件生成加工代码,特别适合复杂自由曲面微结构的加工。综合采用此技术设计了专用微细电火花数控系统,制备了直径30μm,长度3mm的工具电极,使用此电极加工出1mm×0.3mm×0.18mm的雕塑头像。     

飞秒激光玻璃微加工技术

为了研究飞秒激光作用下光学玻璃内部发生的改性过程,利用重复频率为1kHz、中心波长为775am、脉宽为130fs的飞秒激光对光学玻璃进行微加工．结果表明,激光辐照区发生永久性折射率改变,并且玻璃的改性线宽随着激光功率的增加而增加,随激光扫描速度的降低而增加．根据飞秒激光致使光学玻璃发生改性的特点,利用飞秒激光在光学玻璃内部直接刻写了相位光栅和二维图案,研究了相位光栅的衍射特性．     

Technologies and applications of silicon-based micro-optical electromechanical systems: A brief review

Micro-optical electromechanical systems (MOEMS) combine the merits of micro-electromechanical systems (MEMS) and micro-optics to enable unique optical functions for a wide range of advanced applications. Using simple external electromechanical control methods, such as electrostatic, magnetic or thermal effects, Si-based MOEMS can achieve precise dynamic optical modulation. In this paper, we will briefly review the technologies and applications of Si-based MOEMS. Their basic working principles, advantages, general materials and micromachining fabrication technologies are introduced concisely, followed by research progress of advanced Si-based MOEMS devices, including micromirrors/micromirror arrays, micro-spectrometers, and optical/photonic switches. Owing to the unique advantages of Si-based MOEMS in spatial light modulation and high-speed signal processing, they have several promising applications in optical communications, digital light processing, and optical sensing. Finally, future research and development prospects of Si-based MOEMS are discussed.     

面向微加工的虚拟光刻系统建模与实现

提出了一种面向微加工的虚拟光刻系统Litho3D.该系统采用傅立叶光学成像模型、光刻胶曝光及显影模型,实现了投影式光学光刻的三维模拟.它拥有标准的GDSII、CIF版图格式接口和支持各种光学参数(包括数值孔径、波长、离焦量,光刻胶厚度、表面折射率等)的模拟设置.模拟结果的显示采用了体绘制与网格相结合的方法,增强了结果的可视性.此外,光刻模拟结果可以直接导入到虚拟工艺系统ZProcess中作为刻蚀工艺的掩膜输入,实现了光刻工艺与其他微机电系统(MEMS)工艺模拟的无缝集成.一系列模拟结果验证了该系统的可行性.     

Recent Progress in Neural Probes Using Silicon MEMS Technology

Extracellular recordings from the brain are the basis for the fundamental understanding of the complex interaction of electrical signals in neural information transfer. Going beyond wire electrodes and bundles of electrode wires such as tetrodes, multielectrode arrays based on silicon technologies are receiving growing attention, since they enable a pronounced increase in the number of recording sites per probe shaft. In this paper, recent innovations contributed by the authors to the development of probe arrays based on microelectromechanical system (MEMS) technologies within the EU‐funded research project NeuroProbes are described. The resulting structures include passive electrode arrays based on single‐shaft and four‐shaft probes comprising nine planar electrodes per shaft with lengths of up to 8 mm. Further, active probe arrays with complementary metal–oxide–semiconductor (CMOS) circuitry integrated on the probe shaft, enabling the arrangement of 188 electrodes in two columns along a 4‐mm‐long probe shaft with an electrode pitch of only 40 µm, are described. These active probes were developed for an electronic depth control. Further, the paper reports assembly technologies for combining the probe arrays with highly flexible ribbon cables. Applications of the probes in in vivo experiments are summarized. © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.