微/纳机构抗粘附研究进展

粘附现象是微/纳机构中特有的现象,在构件材料强度满足要求的条件下,微/纳机构中的粘附和摩擦是造成其失效的主要原因.如何防止或减轻粘附已成为微/纳机电系统(MEMS/NEMS)领域的研究热点.介绍了微/纳机构中的粘附问题,分析了粘附机理和各种粘附接触模型,说明了表面能法和微凸体积分法防粘附设计微/纳机构的原理,最后阐述了释放干燥工艺、减少实际接触面积和降低表面能等各种抗粘附措施.     

Si基Cu/NiFe薄膜的生长及其粘附特性研究

微机械(MEMS)工艺和集成电路(IC)工艺中,在硅(Si)片上电铸高深宽比坡莫(NiFe)合金材料常出现脱落现象.提出了一种电铸NiFe合金材料的新方法,这种方法制作的合金薄膜厚度达200 μm时不脱落.此方法即对等离子刻蚀后的硅片溅射种子层铜(Cu),然后对种子层进行电镀,当其厚度达到约15 μm时,再进行NiFe合金的电铸.本文用扫描电镜、x射线衍射仪和剥离实验研究了薄膜粘附特性.研究结果表明当对种子层电镀后,随着Cu种子层厚度的增加,Cu/NiFe薄膜与基体的粘附强度增加,而薄膜的残余应力降低;同时Cu膜表面粗糙度增加,也增加了NiFe膜与Cu膜的粘附强度.     

MEMS微悬臂梁在冲击下的粘附失效预测*

MEMS(Micro-electronics Mechanical System)的可靠性已经成为它能否成功地实现商品化的一个重要问题.多晶硅微悬臂梁是MEMS中的一个基本结构,阐述了多晶硅微悬臂梁的粘附失效机理,并利用宏观机械中的理论和可靠性分析方法对表面微加工的多晶硅微悬臂梁的粘附可靠性进行预测,建立了在外载荷下的粘附可靠度预测模型,并利用该模型具体分析了微梁尺寸及外界湿度对可靠度的影响.     

MEMS器件中多层金属薄膜溅射工艺研究

溅射工艺是制作微机电系统(MEMS)器件金属薄膜的主要方式,金属薄膜作为MEMS器件中的掩模层和功能层,要求薄膜应力小,粘附性、均匀性和可焊性好.通过对常用金属薄膜材料特性、多层金属薄膜溅射工艺和质量评价方法的研究得出了优化工艺的的方法,提高了多层金属薄膜的质量.     

基于:CH薄膜的微齿轮的制备

采用低压等离子体化学气相沉积技术在硅片上制备出α∶CH薄膜,以金属铝作为掩膜,利用电子回旋共振微波等离子体反应离子刻蚀法制备微齿轮,再用化学腐蚀的办法将所制备的齿轮从硅片上剥离下来,最后清洗干净后用毛细管把微齿轮组装到一个固定的转轴上.扫描电子显微镜(SEM)测量表明,所得的微齿轮直径270μm左右,厚度12 μm左右,表面平整,侧壁陡直.     

MEMS中永磁材料的微细加工技术研究进展

概述了永磁材料在微机电系统(MEMS)中集成制造方法的研究进展,总结了当前用于制造永磁薄膜的电沉积、溅射、脉冲激光沉积(PLD)和粘结磁体微图形化等4种主要加工技术的优缺点和研究现状,并对未来的发展方向提出了一些观点.     

微加速度计粘附问题的研究及应用

粘附是影响微机电系统(MEMS)可靠性的重要因素之一。针对MEMS的典型产品——微加速度计的粘附问题进行了研究,给出了2种典型的微加速度计的表征粘附特性的剥离数的表达式,并分析了将粘附条件应用于微加速度计的多学科设计优化之中,分析了其对系统结构设计产生的影响。     

Evanohm合金的双环线型微加热器特性研究

以Evanohm合金为材料,设计了一种双环线型微加热器.使用AC磁控溅射技术在硅基底上沉积合金薄膜,并采用微机电系统(MEMS)微加工工艺实现薄膜图形化,以此作为加热器的加热元件.在常温下,研究了所制备的薄膜加热器件的加热性能与电学特性,并在深低温下进一步测试了其电学性能.研究结果表明:此种微型加热器电阻值稳定.在[5...     

微机械薄膜热膨胀系数的测试结构

在微电子机械系统(MEMS)领域,薄膜的热膨胀系数对于微电子器件、MEMS器件,尤其是微热执行器的设计是一个十分重要的参数.本文详细介绍和分析了薄膜热膨胀系数的几种测试结构,对于微机械薄膜热膨胀系数在线测试结构的设计有一定的参考价值.     

基于PI衬底的柔性MEMS电容式触觉力传感器设计与制作

论述了一种可应用于机器人或医学修补技术的触觉传感器及其在旋涂的柔性聚酰亚胺衬底的新制作方法.该传感器是由多层无机和有机薄膜组成的柔性薄膜结构.结合传感器结构特点及各结构层材料的加工性能,进行工艺优化整合.尤其首次在载体硅片与PI衬底之间引进PDMS分离层,使得柔性器件的分离工艺大大简化.最后得到一种简单、低廉且与常规MEMS技术兼容的工艺.所制的传感器结构轻薄,可挠性好,且能贴附在任意形状的物体表面同时实现法向力和切向力的测量.     

De-tethering of high aspect ratio metallic and polymeric MEMS/NEMS parts for the direct pick-and-place assembly of 3D microsystem

We report our study on several de-tethering methods for various high aspect ratio metallic and polymeric MEMS and NEMS parts including 5:1 aspect ratio 50 μm thick metallic (nickel) MEMS parts, 3:1 aspect ratio 1 μm thick sub-micron (350 nm) feature size metallic NEMS actuators, and 10:1 aspect ratio 100 μm thick polymer/metal bi-layer MEMS actuators. Resistive heating was found to be effective for the de-tethering of high aspect ratio metallic MEMS parts. In order to de-tether metallic NEMS parts and polymer/metal bi-layer devices, we performed the milling of tethers using a focused ion beam. Very low current (20 pA) ion beam was found to be effective means of de-tethering the metallic NEMS parts. Relatively larger current (0.3–20 nA) ion beam was found to be good for the polymer/metal bi-layer parts. We demonstrated 3D assembly and complete packaging of the de-tethered high aspect ratio metallic and metal/polymer bilayer MEMS parts.     

Analytical Solution of the Continuous Cellular Automaton for Anisotropic Etching

The fabrication of micro- and nanoelectromechanical systems (MEMS/NEMS) is based on a wide variety of growth and etching technologies sequentially applied throughout process flows which may involve a dozen or more steps, their realistic simulation having become an essential part of the overall design. By focusing in the simulation of anisotropic etching as a complex example of microfabrication, in this paper, we show how to solve analytically the time evolution of the continuous cellular automaton method, thus providing a particularly suitable choice for the realization of realistic simulations for MEMS and NEMS applications. This paper presents a complete theoretical derivation of the analytical solution based on geometrical and kinetic aspects of step flow on any surface, including a new classification of the surface sites based on a mean-field treatment of the propagation of the steps. The results of the corresponding simulations are in good agreement with the experiments. The study can be seen as an example of a general procedure that is applicable to other interface propagation problems.     

Ultra high aspect-ratio MEMS and NEMS on basis of fibrous composite technology

Indisputably, microelectronics is the mother of the MEMS/NEMS technologies. Unfortunately, the majority of developed MEMS and NEMS devices inherited from microelectronics technologies not only of merit but also deficiencies one of which is their planarity. Recently developed devices on the flexible base and also devices with the moving elements on the hinges, in principle, remain geometrically flat. With this micro- and nano-mechanisms (motors, actuators, sensors, etc.) they are not divided with the base (from silicon or another material) large part of which (volume and mass) functionally is not used and has usual of macro sizes (dimensions of a chip). As a result, these ultra modern planar technologies are helpless with the creation of powerful autonomous 3D-devices with the overall sizes ∼(1–10) mm³. The author makes the attempt to estimate the prospects for development and fabrication of topology complex 3D MEMS/NEMS, for example, flaying microrobot and elastic micro motor on the basis of fibrous composites—ultra high aspect-ratio glass structures with predetermined 3D micro- and nano-topologies and embedded wires.     

Nonlinear dynamics of MEMS/NEMS resonators: analytical solution by the homotopy analysis method

Microsystem Technologies - Due to various sources of nonlinearities, micro/nano-electro-mechanical-system (MEMS/NEMS) resonators present highly nonlinear behaviors including softening- or...     

Paired-wire carrying current actuators and piezoelectric beam sensors for microelectromechanical systems

Microsystem Technologies - An alternative actuator for MEMS/NEMS device is proposed and analyzed. The actuator is based on the paired-wires (PW) carrying current concept, which makes the actuator...     

基于鼓膜法的薄膜力学性能测试研究

采用自行研制的鼓膜实验装置,结合迈克尔逊激光干涉位移测量技术,获取薄膜的变形值与压力值之间的关系曲线,以实现薄膜试样力学性能的测试.对鼓膜法测试薄膜力学性能的现状做了评述;对实验原理以及装置设计进行论述;进行实验测量,并对实验结果进行有限元分析与仿真.对纯铝薄膜(纯度99.9％,厚为210 μm)进行鼓膜实验,测得其弹性模量E为68.3 GPa,与资料结果基本一致,说明研制的鼓膜实验装置测量薄膜力学性能方法切实可行.实验装置对于在微/纳机电系统(MEMS/NEMS)中广泛应用的薄膜材料的力学性能表征具有十分重要的意义.     

MEMS/NEMS表面3-D轮廓测量中基于模板的相位解包裹方法

相位解包裹是使用相移显微干涉法测量MEMS/NEMS表面3-D轮廓时的重要步骤.本文针对普通的相位解包裹方法在复杂轮廓或包含非理想数据区的表面轮廓测量中的局限性,提出一种基于模板的广度优先搜索相位展开方法.通过模板的使用,先将非相容区域标记出来,在相位解包裹的过程中绕过这些区域,即可得到准确可靠的相位展开结果.通过具体的应用实例可以证明,使用不同模板可以根据不同应用的需要灵活而准确地实现微纳结构表面3-D轮廓测量中的相位展开.     

Surface micromachining of polycrystalline SiC films usingmicrofabricated molds of SiO2 and polysilicon

As an alternative to conventional SiC reactive ion etching (RIE), polycrystalline (poly-SiC) films were patterned into micron-sized structures using sacrificial SiO₂ and polycrystalline silicon (polysilicon) molds in conjunction with mechanical polishing. The molds were made from thermally grown SiO₂ and LPCVD polysilicon films and were fabricated using conventional patterning techniques. The poly-SiC micromolding process combines film deposition, polishing, and selective wet chemical etching of the molds to achieve the desired pattern. The process is simple and does not suffer from the difficulties associated with RIE of SiC. Micrometer sized lines, spaces, and complex device structures have been patterned using this technique. The micromolding technique has been used in a SiC surface micromachining process to fabricate fully released lateral resonant structures     

基于NEMS技术的介电泳芯片及其关键工艺问题的研究

结合信息技术、生物技术与纳米技术的发展,提出一种基于NEMS技术的“三维纳隙网格阵列微电极生物传感器“设计,用于生物样品在蛋白或细胞水平上的介电泳分离和检测.重点针对传感器制作的关键工艺问题,创新性地提出了一种利用反应离子刻蚀侧向钻蚀效应实现纳隙薄金属悬臂梁结构的理论和方法,此方法对电容式生物传感器的制作有普遍的实践意义.     

Fabrication of glass-like carbon molds to imprint on glass materials by MEMS processing technologies

We processed a precise relief structure on the surface of a glass-like carbon (GC) substrate by applying micro-electro-mechanical-systems (MEMS) technologies, and made a high temperature resistant mold for thermal imprinting on glass materials. An attractive feature of GC is its chemical stability at high temperatures (above 1,000 °C). The down side is its brittleness that makes microfabrication with GC a difficult task. We investigated to find if photolithography combined with reactive-ion-etching (RIE), which are generally used in MEMS fabrication, could be applied for the fabrication of GC molds. In our work with the RIE process, we made masking layers using Au and a positive-tone photoresist. By taking advantage of the difference between the etching rates of the masking materials and GC, we fabricated convex mold patterns with vertical and curved sidewalls. From the experimental results imprinted on Pyrex glass and on quartz, the practicability of using both kinds of GC molds appeared to be quite promising. We believe that in the near future these techniques will be successfully applied in the fabrication of large-size GC molds.