Three-way silicon microvalve for pneumatic applications with electrostatic actuation principle

We present a normally closed electrostatically driven 3-way microvalve which is able to meet the requirements of industrial applications like small form factor, high flow rate, low weight, low power consumption and a short response time. The microvalve consists of a 3 layer full-wafer bonded silicon chip stack mounted on a ceramics substrate and a plastic cap covering the valve. A driver electronics which converts the TTL level to the actuation voltage of 200 V is placed on top of the valve. The valve operates in a pressure range of up to 8 bar and offers a flow rate of approximately 500 sccm. Due to the electrostatic actuation principle the peak power consumption is below 10 mW and the response time is below 1 ms.     

Electrochemical machining: new possibilities for micromachining

A better understanding of high rate anodic dissolution processes is urgently required for electrochemical micromachining (EMM) to become a widely employed manufacturing process in the electronic and precision manufacturing industries particularly in the micromanufacturing domain. A successful attempt has been made to develop an EMM setup for carrying out in depth independent research for achieving satisfactory control of electrochemical machining process parameters to meet the micromachining requirements. The developed EMM setup mainly consists of various sub-components and systems, e.g., mechanical machining unit, microtooling system, electrical power and controlling system and controlled electrolyte flow system, etc. All these system components are integrated in such a way that the developed EMM system setup will be capable of performing basic and fundamental research in the area of EMM fulfilling the requirements of micromachining objectives.     

磁悬浮转子微陀螺的微细加工工艺研究

介绍了磁悬浮转子微陀螺的工作原理及有关的微细加工工艺。磁悬浮转子微陀螺的平面线圈是采用光刻、电镀及溅射等微细加工方法来实现的,微转子的加工有冲压、蒸铝沉积等方法,其中冲压能得到质量较好的微转子;上壳体采用体硅腐蚀来制作。初步的实验表明该方案是行之有效的。     

Multi-layer microstructure fabrication by combining bulk silicon micromachining and UV-LIGA technology

A novel method for fabrication of multi-layer microstructures of microelectro-mechanical system (MEMS) devices is described. This technique, which combines bulk silicon micromachining technique and UV-LIGA technique can overcome some shape limitations of single technique on complex microstructures. To demonstrate this combination, the SU-8 microstructure fabricated in the etched silicon grooves is presented. In this fabrication process, a SU-8 removal method by fuming sulfuric acid was introduced and a novel type of plastics PETG was tried in microhot embossing process. The proposed fabrication process can be applied to fabricating a high-aspect-ratio microstructure for a large displacement actuator and precision sensors. Moreover, this combined process enables the fabrication of more complex structures, which cannot be fabricated by bulk micromachining or UV-LIGA alone.     

单片集成的高性能压阻式三轴高g加速度计的设计、制造和测试

设计、制造并测试了一种单片集成的压阻式高性能三轴高g加速度计,量程可达105g.x和y轴单元均采用一种带微梁的三梁-质量块结构,z轴单元采用三梁-双岛结构.与传统的单悬臂梁结构或者悬臂梁-质量块结构相比,这两种结构均同时具有高灵敏度和高谐振频率的优点.采用ANSYS软件进行了结构分析和优化设计.中间结构层主要制作工艺包括压阻集成工艺和双面Deep ICP刻蚀,并与玻璃衬底阳极键合和上层盖板BCB键合形成可以塑封的三层结构,从而提高加速度计的可靠性.封装以后的加速度计采用落杆方法进行测试,三轴灵敏度分别为2.28,2.36和2.52 μV/g,谐振频率分别为309,302和156 kHz.利用东菱冲击试验台,采用比较校准法测得y轴和z轴加速度计的非线性度分别为1.4%和1.8%.     

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.     

飞秒激光多脉冲烧蚀研究进展

由于飞秒脉冲在烧蚀固体材料时的独特机制，在材料激光微加工方面有其突出的优点，表现出极大的应用潜力。本文主要就国内外多脉冲飞秒烧蚀研究的进展作一简介，包括多脉冲烧蚀的特点，现有的烧蚀机制分析及其应用前景等。     

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。     

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.     

p-Si薄膜在氢氟酸溶液中的电化学抛光

p-Si薄膜在氢氟酸溶液中的电化学抛光是通过阳极溶解降低薄膜表面粗糙度.本文用线性扫描研究了在不同的氢氟酸浓度下的电化学行为,发现随氢氟酸溶液浓度的增加阳极溶解速率也随之增加.当氢氟酸浓度为4％及6％时,可得到平整的表面.电化学抛光技术为制备光亮硅面提供了一种简单可行的方法.