微波ECR等离子体刻蚀AAO模板中HfO_2薄膜的研究
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摘要
采用微波电子回旋共振(ECR)等离子体装置,对用原子层沉积(ALD)方法在阳极氧化铝模板(AAO)上制备的HfO_2薄膜进行了纳米图案化研究。用CF_4、Ar和O_2等离子体,对HfO_2薄膜进行了反应离子束刻蚀,以移除HfO_2。采用高分辨率扫描电子显微镜(SEM)、原子力显微镜(AFM)和能量色散X射线光谱显微(EDX)分析,对样品刻蚀前后的形貌、结构和化学成分进行了表征。实验表明,HfO_2的刻蚀具有定向性,利于高深宽比微机械结构的加工。在其他参数固定的情况下,深宽比高达10∶1的结构中HfO_2的刻蚀速率是微波功率、负脉冲偏压、CF_4/Ar/O_2混合比(Ar含量在0～100%)和工作气压的函数。在0.3 Pa气压、600 W微波功率、100 V偏置电压下,HfO_2拥有0.36 nm/min的可控刻蚀速率,利于HfO_2的精准图案化。刻蚀形貌表明,在CF_4/Ar/O_2等离子体刻蚀之后,刻蚀面非常光滑,具有0.17 nm的均方根线粗糙度。
Nano-structuring of HfO_2 films deposited on AAO(Anodic Aluminum Oxide)template by home-made microwave electron cyclotron resonance(ECR)plasma equipment is described. The remove of HfO_2 films was carried out by the reaction ion beam etching using CF_4,Ar and O_2 plasmas. A combination of high-resolution scanning electron microscopy,atomic force microscopy,and energy-dispersive X-ray spectroscopy microanalysis was used to characterize the before and after samples pattern morphology,structure,and chemical composition. We found that the etch of HfO_2 in our experiments is directional which is favorable to the process of high aspect ratio micro mechanical structures. The etch rate of HfO_2 in the high aspect ratio construction that is up to 10∶1 in our operations was measured as a function of microwave power supply,negative pulsed bias power supply,CF_4/Ar/O_2 mixing ratio in the range of 0 to 100% Ar and working pressure at a fixed the others parameters. The experiments indicate that the optimum etch rate is 0.36 nm/min in our device at gas pressure(0.3 Pa),microwave power(600 W),bias power(100 V). The etched HfO_2 at the bottoms of the AAO template was found to be residue-free and automically smooth with a root mean square line roughness of 0.17 nm after CF_4/Ar/O_2 plasma etching.
Nano-structuring of HfO_2 films deposited on AAO(Anodic Aluminum Oxide)template by home-made microwave electron cyclotron resonance(ECR)plasma equipment is described. The remove of HfO_2 films was carried out by the reaction ion beam etching using CF_4,Ar and O_2 plasmas. A combination of high-resolution scanning electron microscopy,atomic force microscopy,and energy-dispersive X-ray spectroscopy microanalysis was used to characterize the before and after samples pattern morphology,structure,and chemical composition. We found that the etch of HfO_2 in our experiments is directional which is favorable to the process of high aspect ratio micro mechanical structures. The etch rate of HfO_2 in the high aspect ratio construction that is up to 10∶1 in our operations was measured as a function of microwave power supply,negative pulsed bias power supply,CF_4/Ar/O_2 mixing ratio in the range of 0 to 100% Ar and working pressure at a fixed the others parameters. The experiments indicate that the optimum etch rate is 0.36 nm/min in our device at gas pressure(0.3 Pa),microwave power(600 W),bias power(100 V). The etched HfO_2 at the bottoms of the AAO template was found to be residue-free and automically smooth with a root mean square line roughness of 0.17 nm after CF_4/Ar/O_2 plasma etching.
引文
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[12]Min K S,Park B J,Kim S W.Selective Etching of HfO2by Using Inductively-Coupled Ar/C4F8Plasmas and the Removal of Etch Residue on Si by Using an O2Plasma Treatment[J].Journal-Korean Physical Society,2008,53(3):1675-1679.
[13]惠迎雪,刘政.基片温度对磁控溅射HfO2薄膜结构和性能影响分析[J].应用光学,2016,37(6):872-879.
[14]Takahashi K,Ono K.Selective etching of high-k HfO2films over Si in hydrogen-added fluorocarbon(CF4/Ar/H2and C4F8/Ar/H2)plasmas[J].Journal of Vacuum Science&Technology A Vacuum Surfaces&Films,2006,24(3):437-443.
[15]Kitagawa T,Nakamura K,Osari K,et al.Etching of High-k Dielectric HfO2Films in BCl3-Containing Plasmas Enhanced with O2Addition[J].Japanese Journal of Applied Physics,2006,45(8/11):L297-L300.
[16]George S M,Lee Y.Prospects for Thermal Atomic Layer Etching Using Sequential,Self-Limiting Fluorination and Ligand-Exchange Reactions[J].ACS Nano,2016,10(5):4889-4894.
[2]Young-Hee J,Jong-Chang W,Yang X,et al.Temperature Dependence on Dry Etching of Hafnium Oxide Using an Inductively Coupled Plasma[J].Ferroelectrics,2010,406(1):176-184.
[3]徐向东,刘颖,邱克强.HfO2顶层多层介质膜脉宽压缩光栅的离子束刻蚀[J].物理学报,2013(23),1-8.
[4]辛煜,宁兆元,叶超.HfO2在CHF3、Ar和H2的感应耦合等离子体中的刻蚀行为[J].真空科学与技术学报,2004,24(4):309-312.
[5]Shoeb J,Kushner M J.Mechanisms for plasma etching of HfO2gate stacks with Si selectivity and photoresist trimming[J].Journal of Vacuum Science&Technology A:Vacuum,Surfaces,and Films,2009,27(6):1289-1302.
[6]Benedicto M,Galiana B,Molina-Aldareguia J M,et al.Fabrication of HfO2patterns by laser interference nanolithography and selective dry etching for III-V CMOS application[J].Nanoscale research letters,2011,6(1):400.
[7]桑利军.ECR等离子体辅助原子层沉积Al2O3薄膜的研究及其参数诊断[D].北京:北京印刷学院,2009.
[8]George S M,Lee Y.Prospects for Thermal Atomic Layer Etching Using Sequential,Self-Limiting Fluorination and LigandExchange Reactions[J].Acs Nano,2016,10(5):4889.
[9]Kim H S,Yeom G Y,Lee J W,et al.Study of GaN etch mechanisms using inductively coupled Cl2/Ar plasmas[J].Thin Solid Films,1999,341(1):180-183.
[10]Paraschiv V,Baklanov C M,Mikhail R,et al.HF Based Solutions for HfO2Removal;Effect of pH and Temperature on HfO2:SiO2Etch Selectivity[J].Solid State Phenomena,2005,103:97-102.
[11]Shin M H,Na S W,Lee N E,et al.Dry etching of TaN/HfO2gate stack structure by Cl2/SF6/Ar inductively coupled plasma[J].Japanese Journal of Applied Physics,2005,44(7):5811-5818.
[12]Min K S,Park B J,Kim S W.Selective Etching of HfO2by Using Inductively-Coupled Ar/C4F8Plasmas and the Removal of Etch Residue on Si by Using an O2Plasma Treatment[J].Journal-Korean Physical Society,2008,53(3):1675-1679.
[13]惠迎雪,刘政.基片温度对磁控溅射HfO2薄膜结构和性能影响分析[J].应用光学,2016,37(6):872-879.
[14]Takahashi K,Ono K.Selective etching of high-k HfO2films over Si in hydrogen-added fluorocarbon(CF4/Ar/H2and C4F8/Ar/H2)plasmas[J].Journal of Vacuum Science&Technology A Vacuum Surfaces&Films,2006,24(3):437-443.
[15]Kitagawa T,Nakamura K,Osari K,et al.Etching of High-k Dielectric HfO2Films in BCl3-Containing Plasmas Enhanced with O2Addition[J].Japanese Journal of Applied Physics,2006,45(8/11):L297-L300.
[16]George S M,Lee Y.Prospects for Thermal Atomic Layer Etching Using Sequential,Self-Limiting Fluorination and Ligand-Exchange Reactions[J].ACS Nano,2016,10(5):4889-4894.