1、基于扫描电镜的电子束曝光系统Raith GmbH Elphy plus,主要内容,扫描电子显微镜介绍 Raith电子束曝光系统 电子束曝光图形制作 曝光参数 对准操作 纳米器件制作的主要步骤,XL 30 S FEG (a top performing field emission SEM),Acceleration voltage:200 V 30kV Resolution:1.5nm at 10kV, 2.5nm at 1kV Electron spot 1nm, Resolution 1nm STEM within SEM! + CL detector,电子发射枪,电子透镜原理,Elect
2、ron gun produces beam of monochromatic electrons. First condenser lens forms beam and limits current (“coarse knob“). Condenser aperture eliminates high-angle electrons. Second condenser lens forms thinner, coherent beam (“fine knob“ ). Objective aperture (usu. user-selectable) further eliminates hi
3、gh-angle electrons from beam.,Beam “scanned“ by deflection coils to form image. Final objective lens focuses beam onto specimen. Beam interacts with sample and outgoing electrons are detected. Detector counts electrons at given location and displays intensity. Process repeated until scan is finished
4、 (usu. 30 frames/sec).,Cathodaluminescence,Secondary e,Backscattered e,Incident e,Elastically Scattered e,Inelastically Scattered e,Unscattered e,X-rays,Auger e,电子相互作用,Caused by incident electron passing “near“ sample atom and ionizing an electron (inelastic process). Ionized electron leaves sample
5、with very small kinetic energy (5eV) and is called “secondary electron“. (Each incident electron can produce several secondary electrons.) Production of secondary electrons is topography related. Only secondaries near surface (10 nm) exit sample.,FEWER secondary e escape,MORE secondary e escape,二次电子
6、的形成,如何生成二次电子像,Secondary electrons are generated by the interaction of the incident electron beam and the sample. The secondary electrons emerge at all angles. These electrons gathered by electrostatically attracting them to the detector. Knowing both the intensity of secondary electrons emitted and
7、position of the beam, an image is constructed electronically.,Raith电子束曝光系统,曝光精度 30 nm , 器件套刻精度 50 nm,Beam blanker,图形发生器,Beam blanker Amplifier,控制系统界面,Beam blanking,Faraday圆筒测电流,工作方式 高斯束、矢量扫描、固定工作台,Elphy plus主控制界面,曝光图形的制作,图形格式：.CSF或者.GDS,常用软件：elphy plus GDSII databaseLeditAutoCAD等等,曝光之前，必须先知道曝什么！,增加图
8、层,选定图层,选定图层,显示绘图格点,改变绘图格点间距,选用画笔,曝光图形设计注意事项,最小尺寸：线宽、间距（考虑临近效应） 对准标记要适合（多用十字） 需要曝光的图形要远离对准标记 两层之间的对准要留容错 注意曝光的顺序 注意图形交叠，特别是场拼接处的图形,d,曝光中的主要操作对准,1、源漏电极要压在纳米管上 2、栅电极要盖在源漏之间,难点：很多地方不能看！,对准调节,曝光之前，必须先知道在哪里曝光！,扫描电镜的坐标 （x,y）,曝光系统定义的坐标 （u,v）,两套坐标的刻度校准,标准样品,三点校正确定u、v坐标,（1.0,0） (1.5,0) (1.5,0.5),第一次三点校正,第二次三点校正,（1.07,1.05）,（1.43,1.05）,（1.45,1.43）,曝光参数设置扫描电镜,加速电压 如：20kV Spot size 工作高度选择,曝光参数设置Elphy plus,图层选择 电流密度 曝光剂量 移动步距,曝光剂量的选择,手动对准标记,纳米器件的主要制作步骤,基片准备（要求带标记） 纳米线/管分散和定位 涂电子束抗蚀剂（如PMMA） 曝光图形设计 电子束曝光、显影 蒸镀金属膜 剥离 测量,基片准备和样品分散,定位和曝光图形设计,镀膜和剥离,
