Micron-scale polymer-metal cantilever actuators fabricated by focused ion beam

Polymer-metal microcantilever actuators have been fabricated using an innovative approach based on focused ion beam micromachining technology. The fabrication involves depositing a thin metal film onto the surface of the polymer and machining using the ion beam. The microcantilever created is then extracted and transferred to a desirable support using a micromanipulator. This approach demonstrates the potential for maskless and resistless prototyping of cantilevers that can be evaluated for use as MEMS/NEMS actuators. Nanometer-scale displacement of the resulting polystyrene-platinum bimorph microactuator with respect to temperature change is demonstrated via visual monitoring in a scanning electron microscope with a heating stage. The performance of the bimorph cantilever microactuators is verified using both analytical and finite element modeling.     

Controlling parameters of focused ion beam (FIB) on high aspect ratio micro holes milling

Focused ion beam (FIB) direct milling is now recognized as a new method of fabrication, due to high flexibility in milling dimensions, the possible geometries and the material selectivity. This paper discusses the fabrication of micro holes using FIB direct milling in terms of high aspect ratio structures, including FIB parameters and the major effects of FIB milling. It is deduced that sputter yield of material gives a major impact to the depth of milling. Optimization parameters coupled control of FIB direct milling will provide a precise means of fabricating of high aspect ratio micro holes whilst resolving the problem of re-deposition and amorphisation which is common in micro milling.     

Study on the method for the reliability test of focused ion beam

We investigate the reliability of the focused ion beam (FIB) system with the designed evaluation patterns. The reliability test patterns are composed of three parts, which are the ion beam quality patterns, the ion beam scanning ability patterns and the stage system patterns. The designed patterns are fabricated with the commercial FIB system, and the common nanometer scale measurement systems, the atomic force microscopy and the scanning electron microscopy are used to evaluate the fabricated patterns. The measurement of the absolute length becomes important in the reliability test, and the measurement systems are calibrated with the standard patterns. The measurement results show the proposed patterns are suitable to measure the characteristics of FIB system and also other machines which can fabricate nanometer scale and high-aspect-ratio patterns.     

Deposition property investigation of a focused ion beam for a high-aspect-ratio metal tip

We investigate the deposition properties of a focused ion beam for the fabrication of metal structures. We performed experiments under various beam currents, deposition times, and initial design diameters and analyzed the fabricated diameters and heights with recorded video clips. We observed abnormal deposition phenomena which show the etching effect as well as deposition, and investigated the relationship between the etching and parameters such as beam current and designed diameter. We apply these conditions and finally fabricate a high-aspect-ratio tip without abnormal deposition phenomena.     

Molecular dynamic simulation of orientation-dependent effect on silicon crystalline during sputtering process of focused ion beam

Microsystem Technologies - In this paper, experiments and molecular dynamic simulation are performed to investigate the crystal orientation-dependent effects in a focused ion beam (FIB) sputtering...     

利用电子束曝光系统制作高深宽比图形的研究

为了加工具有高深宽比的器件,采用能量连续递减近似模型,运用蒙特卡罗方法分析高能电子束曝光领域的电子散射轨迹及背散射电子对曝光分辨力的影响,探讨了制作高深宽比图形的工艺条件。计算机模拟结果与实验结果吻合得很好,表明在其它实验条件不变的情况下,较高的加速电压能提高图形的高深宽比,提供了制作高深宽比图形的一种方法。     

Fabrication of Fresnel zone plates with high aspect ratio by soft X-ray lithography

High focusing efficiency Fresnel zone plates for hard X-ray imaging is fabricated by electron beam lithography, soft X-ray lithography, and gold electroplating techniques. Using the electron beam lithography, Fresnel zone plates which has an outermost zone width of 100 nm and thickness of 250 nm has been fabricated. Fresnel zone plates with outermost zone width of 150 nm and thickness of 660 nm has been fabricated by using soft X-ray lithography.     

Formation of non-equilibrium phases and associated structural transition in the Pd-Ta system induced by ion beam mixing

For the Pd-Ta system characterized by a negative heat of formation of -78 kJ/mol, 200 keV xenon ion beam mixing with nano-sized Pd-Ta multilayered films was conducted to study the non-equilibrium phase formation. The results showed that uniform amorphous alloys can be formed within a composition range of 25 at%-78 at% Ta, which falls in the maximum possible amorphization range of 22 at%-80 at% Ta predicted by the empirical model. Moreover, two metastable crystalline phases both of FCC structure, yet with di...     

Fast and accurate X-ray lithography simulation enabled by using Monte Carlo method. New version of DoseSim: a software dedicated to deep X-ray lithography (LIGA)

This paper presents the recent development of a simulation tool for deep X-ray lithography. The simulation tool named DoseSim (Meyer et al. in Rev Sci Instrum 74(2):1113–1119, 2003) is a graphical user interface, working under Windows, specially dedicated to the necessary requirements of X-ray lithography setting at a synchrotron. The previous version included the computation of synchrotron radiation from bending magnets, the effects of the optical properties of materials, single mirror and the necessary parameters for the resist exposure. New functionalities, including among others, the exposure time calculation, the insertion of a double mirror, secondary effects (Fresnel diffraction, dose deposited under the absorber) have been added. Also, DoseSim includes traceability concerning the database and calculations used, and de facto the results obtained. Furthermore, Monte Carlo calculations using the PENetration and Energy LOss of Positrons and Electrons (PENELOPE) (Salvat et al.in OECD/NEA Data Bank, France, NEA N°6416, http://www.nea.fr/lists/penelope.html, 2008) code of the spatial distribution of the dose deposited by an X-ray beam in a resist are used. The PENELOPE results (simulations were done mono-energetically for a large range of energy) are the basis of the DoseSim routines for the calculations of the absorbed dose behind the absorber, and at the interface resist/seed layer/substrate. Example of calculations will be discussed along with the effects on dose from different seed layers and substrates.     

利用载噪比比较法测量天线G/T值研究

天线系统的增益G与接收系统噪声温度T的比值称之为G／T值,是信道各参数中十分重要的技术指标,是衡量地面站灵敏度的质量指标,G／T值越高,表明地面站检测来自卫星信号的能力越强。利用频谱仪,低噪声下变频器以及功分器对于天线系统的G／T值进行测试,利用载噪比比较法对天线系统的G/T值进行测量,介绍了该方法计算时的公式和原理,通过标准喇叭的G/T值,融合待测天线和标准增益喇叭分别目标卫星信标,可获得各自的归一化载噪比,得到最终的天线G/T值。经过具体的测试实验,得到了天线的G/T值,实验证明,该方法确实行之有效。     

Identification of a potential proton donor to the linking oxygen atom in a three-metal ion assisted catalysis pathway catalyzed by Fructose-1, 6-bisphosphatase

In this paper, the dephosphorylation mechanism of FBP to F6P catalyzed by the Fructose-1, 6-bisphosphatase (St-Fbp) from Sulfolobus tokodaii was studied using quantum mechanical/molecular mechanical (QM/MM) approach. Based on the experimental results, total five possible catalytic mechanisms (path1-path4′) were designed. The most possible dephosphorylation reaction follows a two-step mechanism (path2): a dephosphorylation process (with D12 being an base of W6 and residue K133 being the proton donor of the linking FBP:O4) and a proton exchange process (between K133 and the water W1). Furthermore, the three-step of path4 is also possible: a dephosphorylation process (with D54 being the base of W6 and residue K133 being the proton donor of the linking FBP:O4) and two proton exchange processes (first between residues D54 and D12 then between K133 and the water W1). The relative low energy of this pathway suggests that D54 might also be a base except D12. Our calculations indicate that K133 is the preferred proton donor during the breaking of the phosphate bond O4-P1, with the W1 being an alternative proton donor to access to a more stable product. Findings here give a new insight into the understanding of catalytic mechanism of FBPase.     

A comment on: “Fast and numerically stable methods for the computation of Zernike moments” by Singh et al. [Pattern Recognition, 43(2010), Pages 2497-2506]

The aim of the present comment is to point out that the q-Recursive relation introduced by Singh et al. is wrong. These errors have been corrected in the comment. The numerical experiments show that the correct recurrence relation is consistent with the original q-Recursive method.