采用数字微镜器件(DMD)无掩模光刻技术,以飞秒激光为光源,结合大面积拼接的方法快速制备了具有较高分辨率和毫米尺寸的大面积微纳结构。提出以单子场投影线扫描的方式进一步改善由于光场能量分布不均匀引起的结构边缘粗糙的问题,极大地...采用数字微镜器件(DMD)无掩模光刻技术,以飞秒激光为光源,结合大面积拼接的方法快速制备了具有较高分辨率和毫米尺寸的大面积微纳结构。提出以单子场投影线扫描的方式进一步改善由于光场能量分布不均匀引起的结构边缘粗糙的问题,极大地降低了线条的边缘粗糙度,有效地控制了结构的精度。本研究以半导体领域常用的正性光刻胶为主要研究对象,实现了面积为7.4 mm 2的1μm等间距线阵列和面积为38.7 mm 2的10μm等间距线阵列结构的快速制备。本研究为大面积微纳结构制备提供了一种新方法,所制备结构可应用于气液流动、药物输运及晶体生长等领域。展开更多
The objective of this paper is to experimentally investigate the cavitation patterns and corresponding hydrodynamics of the hydrofoil with leading edge roughness.The aims are to(1)understand the effect of the leading ...The objective of this paper is to experimentally investigate the cavitation patterns and corresponding hydrodynamics of the hydrofoil with leading edge roughness.The aims are to(1)understand the effect of the leading edge roughness on the hydrodynamic performance,and(2)have a good knowledge of the interaction between the leading edge roughness and the cavitation patterns.Experimental results are indicated for the NACA 66 hydrofoils with and without leading edge roughness at different incidence angles for sub and cavitation conditions.The experiments are conducted in the EPFL high-speed cavitation tunnel(Avellan 2015).The results showed that the leading edge roughness has a significant effect on the hydrodynamic performance at the sub cavitation,suppressing the formation of the incipient cavitation.The lift coefficient of the hydrofoil without leading edge roughness is larger than that of the hydrofoil with leading edge roughness,while for the drag coefficients,the results are contrary for the lift coefficient,and the maximum lift-to-drag ratio angle is delayed for the hydrofoil with leading edge roughness.The leading edge roughness modified the local pressure distribution at the leading edge region,which in turn significantly increased the minimum pressure coefficient,hence the incipient cavitation number of the hydrofoil with leading edge roughness.The formation and evolution of the transient cavity for the cloud cavitation is little affected by the leading edge roughness.展开更多
Lower surface roughness and sharper cutting edge are beneficial for improving the machining quality of the cut?ting tool, while coatings often deteriorate them. Focusing on the diamond coated WC?Co milling cutter, the...Lower surface roughness and sharper cutting edge are beneficial for improving the machining quality of the cut?ting tool, while coatings often deteriorate them. Focusing on the diamond coated WC?Co milling cutter, the abrasive flow machining(AFM) is selected for reducing the surface roughness and sharpening the cutting edge. Comparative cutting tests are conducted on di erent types of coated cutters before and after AFM, as well as uncoated WC?Co one, demonstrating that the boron?doped microcrystalline and undoped fine?grained composite diamond coated cutter after the AFM(AFM?BDM?UFGCD) is a good choice for the finish milling of the 6063 Al alloy in the present case, because it shows favorable machining quality close to the uncoated one, but much prolonged tool lifetime. Besides, compared with the micro?sized diamond films, it is much more convenient and e cient to finish the BDM?UFGCD coated cutter covered by nano?sized diamond grains, and resharpen its cutting edge by the AFM, owing to the lower initial surface roughness and hardness. Moreover, the boron incorporation and micro?sized grains in the underly?ing layer can enhance the film?substrate adhesion, avoid the rapid film removal in the machining process, and thus maximize the tool life(1040 m, four times more than the uncoated one). In general, the AFM is firstly proposed and discussed for post?processing the diamond coated complicated cutting tools, which is proved to be feasible for improving the cutting performance展开更多
Although several years delayed than its initial plan, extreme UV lithography (EUVL) with 13.5nm wavelength has been finally implemented into high volume manufacture (HVM) of mainstream semiconductor industry since 201...Although several years delayed than its initial plan, extreme UV lithography (EUVL) with 13.5nm wavelength has been finally implemented into high volume manufacture (HVM) of mainstream semiconductor industry since 2018. With the delivery and installation of ASML EUV scanners in those giant Fab players like Samsung, TSMC and Intel, EUV lithography is becoming a sort of industry standard exposure metrology for those critical layers of advanced technology nodes beyond 7nm. Although ASML NXE EUVL scanner is the only commercialized EUV exposure system available on the market, its development is the concentration of all essence from worldwide industrial and academic collaboration. It is becoming more and more important not only for fab runners but also for main stream fabless design houses to understand and participate the progress of EUVL. In this review, working principles, module structures and technical challenges have been briefly discussed regarding each EUV subsystem, including light source, reflection mirrors and system, reticle module as well as photoresist development. EUV specific issues of light intensity, defectivity within reflection system, line edge roughness (LER) and mask 3D effects have been focused respectively and promising solutions have been summarized as well.展开更多
文摘采用数字微镜器件(DMD)无掩模光刻技术,以飞秒激光为光源,结合大面积拼接的方法快速制备了具有较高分辨率和毫米尺寸的大面积微纳结构。提出以单子场投影线扫描的方式进一步改善由于光场能量分布不均匀引起的结构边缘粗糙的问题,极大地降低了线条的边缘粗糙度,有效地控制了结构的精度。本研究以半导体领域常用的正性光刻胶为主要研究对象,实现了面积为7.4 mm 2的1μm等间距线阵列和面积为38.7 mm 2的10μm等间距线阵列结构的快速制备。本研究为大面积微纳结构制备提供了一种新方法,所制备结构可应用于气液流动、药物输运及晶体生长等领域。
基金The authors gratefully acknowledge the great help of Dr.Mohamed Farhat(EPFL-LMH)and the support by the National Natural Science Foundation of China(Grant Nos:51909002,51839001.and 91752105)the Fundamental Research Funds for the Central Universities,and the Open Fund for Key Laboratory of Fluid and Power Machinery,Ministry of Education(Grant Nos:szjj2018-124 and szjj2019-024).
文摘The objective of this paper is to experimentally investigate the cavitation patterns and corresponding hydrodynamics of the hydrofoil with leading edge roughness.The aims are to(1)understand the effect of the leading edge roughness on the hydrodynamic performance,and(2)have a good knowledge of the interaction between the leading edge roughness and the cavitation patterns.Experimental results are indicated for the NACA 66 hydrofoils with and without leading edge roughness at different incidence angles for sub and cavitation conditions.The experiments are conducted in the EPFL high-speed cavitation tunnel(Avellan 2015).The results showed that the leading edge roughness has a significant effect on the hydrodynamic performance at the sub cavitation,suppressing the formation of the incipient cavitation.The lift coefficient of the hydrofoil without leading edge roughness is larger than that of the hydrofoil with leading edge roughness,while for the drag coefficients,the results are contrary for the lift coefficient,and the maximum lift-to-drag ratio angle is delayed for the hydrofoil with leading edge roughness.The leading edge roughness modified the local pressure distribution at the leading edge region,which in turn significantly increased the minimum pressure coefficient,hence the incipient cavitation number of the hydrofoil with leading edge roughness.The formation and evolution of the transient cavity for the cloud cavitation is little affected by the leading edge roughness.
基金Supported by National Natural Science Foundation of China(Grant No.51275302)China Postdoctoral Science Foundation Special Funded Project(Grant No.2016T90370)China Postdoctoral Science Foundation(Grant No.2015M580327)
文摘Lower surface roughness and sharper cutting edge are beneficial for improving the machining quality of the cut?ting tool, while coatings often deteriorate them. Focusing on the diamond coated WC?Co milling cutter, the abrasive flow machining(AFM) is selected for reducing the surface roughness and sharpening the cutting edge. Comparative cutting tests are conducted on di erent types of coated cutters before and after AFM, as well as uncoated WC?Co one, demonstrating that the boron?doped microcrystalline and undoped fine?grained composite diamond coated cutter after the AFM(AFM?BDM?UFGCD) is a good choice for the finish milling of the 6063 Al alloy in the present case, because it shows favorable machining quality close to the uncoated one, but much prolonged tool lifetime. Besides, compared with the micro?sized diamond films, it is much more convenient and e cient to finish the BDM?UFGCD coated cutter covered by nano?sized diamond grains, and resharpen its cutting edge by the AFM, owing to the lower initial surface roughness and hardness. Moreover, the boron incorporation and micro?sized grains in the underly?ing layer can enhance the film?substrate adhesion, avoid the rapid film removal in the machining process, and thus maximize the tool life(1040 m, four times more than the uncoated one). In general, the AFM is firstly proposed and discussed for post?processing the diamond coated complicated cutting tools, which is proved to be feasible for improving the cutting performance
文摘Although several years delayed than its initial plan, extreme UV lithography (EUVL) with 13.5nm wavelength has been finally implemented into high volume manufacture (HVM) of mainstream semiconductor industry since 2018. With the delivery and installation of ASML EUV scanners in those giant Fab players like Samsung, TSMC and Intel, EUV lithography is becoming a sort of industry standard exposure metrology for those critical layers of advanced technology nodes beyond 7nm. Although ASML NXE EUVL scanner is the only commercialized EUV exposure system available on the market, its development is the concentration of all essence from worldwide industrial and academic collaboration. It is becoming more and more important not only for fab runners but also for main stream fabless design houses to understand and participate the progress of EUVL. In this review, working principles, module structures and technical challenges have been briefly discussed regarding each EUV subsystem, including light source, reflection mirrors and system, reticle module as well as photoresist development. EUV specific issues of light intensity, defectivity within reflection system, line edge roughness (LER) and mask 3D effects have been focused respectively and promising solutions have been summarized as well.
