电铸金属光栅中金属沉积过程的在线监测
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摘要
在使用电铸方法制作金属光栅时,采用传统的计时电铸方法常常不能保证金属栅条具有精确的沉积厚度。为了能够实时监测光栅栅条的沉积厚度,以实现电铸截止时刻的精确判断,建立了基于衍射效率判断金属沉积厚度的在线监测系统。采用严格耦合波理论计算了Au在光刻胶沟槽中进行沉积时,衍射效率随Au沉积厚度的变化规律,并讨论了光刻胶占宽比、电铸电流密度对衍射效率的影响;计算了电铸池、镀液对监测激光能量造成的损耗。实验得到的效率曲线与仿真结果相一致;电铸池、镀液对光能的损耗达94. 88%。实验结果表明,采用在线监测方法实时判断金属沉积厚度是合理有效的;光刻胶占宽比对在线监测影响不大;电铸电流密度对在线监测有影响,且电流密度越高越有利于截止点的判断。
During the fabrication process of metallic gratings using electro-deposition,the thickness of deposited metal usually cannot be precisely controlled by the traditional timing method. In order to monitor the deposit thickness of grating bars and precisely stop depositing metal in a timely manner during the fabrication of metallic gratings,an in-situ monitoring system based on diffraction efficiency measurements was introduced. The change law of diffraction efficiency varying with Au deposition thickness was calculated using the rigorous coupled wave analysis( RCWA) method and the effect of the photoresistor grating's duty cycle and deposition current density on diffraction efficiency was discussed. The energy loss of monitoring lasers in the system was also calculated. The efficiency curve of the experiment coincides with simulation and the energy loss induced by the electro-deposition pool and solution was up to 94. 88%. The experimental results indicate that the in-situ monitoring system is effective in estimating the thickness of deposited metal during the fabrication of metallic gratings. The duty cycle of photoresistor gratings has less influence on in-situ monitoring than that of deposition current density and a higher current density was more beneficial for monitoring.
During the fabrication process of metallic gratings using electro-deposition,the thickness of deposited metal usually cannot be precisely controlled by the traditional timing method. In order to monitor the deposit thickness of grating bars and precisely stop depositing metal in a timely manner during the fabrication of metallic gratings,an in-situ monitoring system based on diffraction efficiency measurements was introduced. The change law of diffraction efficiency varying with Au deposition thickness was calculated using the rigorous coupled wave analysis( RCWA) method and the effect of the photoresistor grating's duty cycle and deposition current density on diffraction efficiency was discussed. The energy loss of monitoring lasers in the system was also calculated. The efficiency curve of the experiment coincides with simulation and the energy loss induced by the electro-deposition pool and solution was up to 94. 88%. The experimental results indicate that the in-situ monitoring system is effective in estimating the thickness of deposited metal during the fabrication of metallic gratings. The duty cycle of photoresistor gratings has less influence on in-situ monitoring than that of deposition current density and a higher current density was more beneficial for monitoring.
引文
[1]CHEN J,BOS P J,VITHANA H,et al..An electro-optically controlled liquid crystal diffraction grating[J].Applied Physics Letters,1995,67(18):2588-2590.
[2]PFEIFFER F,WEITKAMP T,BUNK O,et al..Phase retrieval and differential phase-contrast imaging with low-brilliance X-ray sources[J].Nat.Phys.,2006,2(4):258-261.
[3]柳龙华,刘刚,熊瑛,等.大高宽比、高线密度X射线透射光栅的制作[J].光学精密工程,2009,17(1):72-75.LIU L H,LIU G,XIONG Y,et al..Fabrication of high-aspect-ratio and high-density X-ray transmission grating[J].Opt.Precision Eng.,2009,17(1):72-75.(in Chinese)
[4]罗跃川,张志友,石莎,等.提高OLED光导出效率的异形金属光栅的设计与优化[J].发光学报,2010,31(6):784-789.LUO Y CH,ZHANG ZH Y,SHI SH,et al..Design and optimizing of an abnormal metal grating used to enhance the lightoutput efficiency of organic light-emitting diode[J].Chinese Journal of Luminescence,2010,31(6):784-789.(in Chinese)
[5]刘镜,刘娟,王涌天,等.亚波长金属光栅的表面等离子体激元共振特性[J].中国光学,2011,4(4):363-368.LIU J,LIU J,WANG Y T,et al..Resonant properties of sub-wavelength metallic gratings[J].Chinese Optics,2011,4(4):363-368.(in Chinese)
[6]王子强.单级衍射光栅的设计与制作[D].长春:长春理工大学,2013.WANG Z Q.The design and fabrication of single-order diffraction grating[D].Changchun:Changchun University of Science and Technology,2013.(in Chinese)
[7]杜立群,鲍其雷,赵明,等.在金属基底上制作高深宽比金属微光栅的方法[J].光学精密工程,2015,23(3):700-707.DU L Q,BAO Q L,ZHAO M,et al..Fabrication of metal micro-grating with high aspect ratio on metal substrate[J].Opt.Precision Eng.,2015,23(3)700-707.(in Chinese)
[8]王鑫,王永红,吕有斌,等.SU-8光刻胶应变分布光学全场检测方法[J].中国光学,2016,9(3):379-384.WANG X,WANG Y H,LY B,et al..Whole field optical detection method of strain distribution of SU-8 photoresist[J].Chinese Optics,2016,9(3):379-384.(in Chinese)
[9]ROMANO L,VILA-COMAMALA J,KAGIAS M,et al.High aspect ratio metal microcasting by hot embossing for X-ray optics fabrication[C].42ndMicro-and nano-engineering conference MNE,2017,176:6-10.
[10]TIWARI P,MONDAL P,SRIVASTAVA A K,et al.Fabrication of high aspect ratio submicron gratings on 100 nm titanium membranes using electron beam lithography[J].AIP Conference.Proceedings,2017,1832(1):060023.
[11]KENNTNER J,ALTAPOVA V,GRUND T,et al.Fabrication and characterization of analyzer gratings with high aspect ratios for phase contrast imaging using a Talbot interferometer[J].AIP Conference.Proceedings,2012,1437(1):89-93.
[12]DAVID C,BRUDER J,ROHBECK T,et al..Fabrication of diffraction gratings for hard X-ray phase contrast imaging[J].Microelectronic Engineering,2007,84(5-8):1172-1177.
[13]GREGUS J A,GREEN C A,YOON E,et al..Real-time latent image monitoring during holographic fabrication of submicron diffraction gratings[J].Journal of Vacuum Science&Technology B Microelectronics&Nanometer Structures,1993,11(6):2468-2472.
[14]赵劲松,李立峰,吴振华.全息光栅实时显影监测曲线的理论模拟[J].光学学报,2004,24(8):1146-1150.ZHAO J S,LI L F,WU ZH H.Modeling of in-situ monitoring curves during development of holographic gratings[J].Acta Optica Sinica,2004,24(8):1146-1150.(in Chinese)
[15]孔鹏,巴音贺希格,李文昊,等.全息光栅非对称曝光显影的理论模拟及实时监测[J].光学学报,2010,30(1):65-69.KONG P,BAYANHESHIG,LI W H,et al..Modeling and in-situ monitoring of the asymmetric exposure and development of holographic grating[J].Acta Optica Sinica,2010,30(1):65-69.(in Chinese)
[16]SVAKHIN A S,SYCHUGOV V A,TIKHOMIROV A E.Diffraction gratings with high optical strength for laser resonators[J].Quantum Electronics,1994,24(3):233-235.
[17]林华.介质膜光栅:光刻胶掩模占宽比和离子束刻蚀槽深的监控[D].北京:清华大学,2005.LIN H.Multilayer dielectric gratings:in-situ monitoring of duty cycle of photoresist mask and ion-beam-etched groove depth[D].Beijing:Tsinghua University,2005.(in Chinese)
[18]樊叔维.任意槽形光栅衍射特性的矢量理论分析与计算[J].光学精密工程,2000,8(1):5-10.FAN SH W.Vector theory analysis and numerical calculation for any shape profile dielectric gratings[J].Opt.Precision Eng.,2000,8(1):5-10.(in Chinese)
[19]陈勇.软X射线自支撑闪耀透射光栅的制作[D].合肥:中国科学技术大学,2013.CHEN Y.Fabrication of soft X-ray freestanding blazed transmission gratings[D].Hefei:University of Science and Technology of China,2013.(in Chinese)
[20]YANG J,WANG ZH,WANG F,et al..Atomically thin optical lenses and gratings[J].Light:Science&Applications,2016,5(3):e16046.
[21]曹艳波,艾华.亚波长闪耀光栅矢量衍射效率计算[J].中国光学与应用光学,2010,3(6):679-683.CAO Y B,AI H.Calculation of vectorial diffraction efficiency of subwavelength blazed gratings[J].Chinese Journal of Optics and Applied Optics,2010,3(6):679-683.(in Chinese)
[22]王斌.亚波长介质光栅设计简化模式法的修正及相关研究[D].北京:中国科学院大学,2014.WANG B.Modification and research on simplified modal method for dielectric subwavelength gratings design[D].Beijing:University of Chinese Academy of Sciences,2014.(in Chinese)
[2]PFEIFFER F,WEITKAMP T,BUNK O,et al..Phase retrieval and differential phase-contrast imaging with low-brilliance X-ray sources[J].Nat.Phys.,2006,2(4):258-261.
[3]柳龙华,刘刚,熊瑛,等.大高宽比、高线密度X射线透射光栅的制作[J].光学精密工程,2009,17(1):72-75.LIU L H,LIU G,XIONG Y,et al..Fabrication of high-aspect-ratio and high-density X-ray transmission grating[J].Opt.Precision Eng.,2009,17(1):72-75.(in Chinese)
[4]罗跃川,张志友,石莎,等.提高OLED光导出效率的异形金属光栅的设计与优化[J].发光学报,2010,31(6):784-789.LUO Y CH,ZHANG ZH Y,SHI SH,et al..Design and optimizing of an abnormal metal grating used to enhance the lightoutput efficiency of organic light-emitting diode[J].Chinese Journal of Luminescence,2010,31(6):784-789.(in Chinese)
[5]刘镜,刘娟,王涌天,等.亚波长金属光栅的表面等离子体激元共振特性[J].中国光学,2011,4(4):363-368.LIU J,LIU J,WANG Y T,et al..Resonant properties of sub-wavelength metallic gratings[J].Chinese Optics,2011,4(4):363-368.(in Chinese)
[6]王子强.单级衍射光栅的设计与制作[D].长春:长春理工大学,2013.WANG Z Q.The design and fabrication of single-order diffraction grating[D].Changchun:Changchun University of Science and Technology,2013.(in Chinese)
[7]杜立群,鲍其雷,赵明,等.在金属基底上制作高深宽比金属微光栅的方法[J].光学精密工程,2015,23(3):700-707.DU L Q,BAO Q L,ZHAO M,et al..Fabrication of metal micro-grating with high aspect ratio on metal substrate[J].Opt.Precision Eng.,2015,23(3)700-707.(in Chinese)
[8]王鑫,王永红,吕有斌,等.SU-8光刻胶应变分布光学全场检测方法[J].中国光学,2016,9(3):379-384.WANG X,WANG Y H,LY B,et al..Whole field optical detection method of strain distribution of SU-8 photoresist[J].Chinese Optics,2016,9(3):379-384.(in Chinese)
[9]ROMANO L,VILA-COMAMALA J,KAGIAS M,et al.High aspect ratio metal microcasting by hot embossing for X-ray optics fabrication[C].42ndMicro-and nano-engineering conference MNE,2017,176:6-10.
[10]TIWARI P,MONDAL P,SRIVASTAVA A K,et al.Fabrication of high aspect ratio submicron gratings on 100 nm titanium membranes using electron beam lithography[J].AIP Conference.Proceedings,2017,1832(1):060023.
[11]KENNTNER J,ALTAPOVA V,GRUND T,et al.Fabrication and characterization of analyzer gratings with high aspect ratios for phase contrast imaging using a Talbot interferometer[J].AIP Conference.Proceedings,2012,1437(1):89-93.
[12]DAVID C,BRUDER J,ROHBECK T,et al..Fabrication of diffraction gratings for hard X-ray phase contrast imaging[J].Microelectronic Engineering,2007,84(5-8):1172-1177.
[13]GREGUS J A,GREEN C A,YOON E,et al..Real-time latent image monitoring during holographic fabrication of submicron diffraction gratings[J].Journal of Vacuum Science&Technology B Microelectronics&Nanometer Structures,1993,11(6):2468-2472.
[14]赵劲松,李立峰,吴振华.全息光栅实时显影监测曲线的理论模拟[J].光学学报,2004,24(8):1146-1150.ZHAO J S,LI L F,WU ZH H.Modeling of in-situ monitoring curves during development of holographic gratings[J].Acta Optica Sinica,2004,24(8):1146-1150.(in Chinese)
[15]孔鹏,巴音贺希格,李文昊,等.全息光栅非对称曝光显影的理论模拟及实时监测[J].光学学报,2010,30(1):65-69.KONG P,BAYANHESHIG,LI W H,et al..Modeling and in-situ monitoring of the asymmetric exposure and development of holographic grating[J].Acta Optica Sinica,2010,30(1):65-69.(in Chinese)
[16]SVAKHIN A S,SYCHUGOV V A,TIKHOMIROV A E.Diffraction gratings with high optical strength for laser resonators[J].Quantum Electronics,1994,24(3):233-235.
[17]林华.介质膜光栅:光刻胶掩模占宽比和离子束刻蚀槽深的监控[D].北京:清华大学,2005.LIN H.Multilayer dielectric gratings:in-situ monitoring of duty cycle of photoresist mask and ion-beam-etched groove depth[D].Beijing:Tsinghua University,2005.(in Chinese)
[18]樊叔维.任意槽形光栅衍射特性的矢量理论分析与计算[J].光学精密工程,2000,8(1):5-10.FAN SH W.Vector theory analysis and numerical calculation for any shape profile dielectric gratings[J].Opt.Precision Eng.,2000,8(1):5-10.(in Chinese)
[19]陈勇.软X射线自支撑闪耀透射光栅的制作[D].合肥:中国科学技术大学,2013.CHEN Y.Fabrication of soft X-ray freestanding blazed transmission gratings[D].Hefei:University of Science and Technology of China,2013.(in Chinese)
[20]YANG J,WANG ZH,WANG F,et al..Atomically thin optical lenses and gratings[J].Light:Science&Applications,2016,5(3):e16046.
[21]曹艳波,艾华.亚波长闪耀光栅矢量衍射效率计算[J].中国光学与应用光学,2010,3(6):679-683.CAO Y B,AI H.Calculation of vectorial diffraction efficiency of subwavelength blazed gratings[J].Chinese Journal of Optics and Applied Optics,2010,3(6):679-683.(in Chinese)
[22]王斌.亚波长介质光栅设计简化模式法的修正及相关研究[D].北京:中国科学院大学,2014.WANG B.Modification and research on simplified modal method for dielectric subwavelength gratings design[D].Beijing:University of Chinese Academy of Sciences,2014.(in Chinese)