FESEM JEOL JSM6701F操作手册

STANDARD OPERATING PROCEDURES(SOPs) for theJEOL JSM-6701FFIELD EMISSION SCANNING ELECTRON MICROSCOPE (FESEM)Chemistry Department2009TABLE OF CONTENTS1. Summary (3)2. Introduction (4)3. Materials Compatibilities (5)4. SEM Lab Sa fety (6)4.1 Personal Protect Equipment (PPE) (6)4.2Risk Assessment (7)4.3 The replacement of the oil mist filter of the rotary pumps (7)4.3 Safety issues related to SEM sample s and sample preparation (7)4.4 Other lab safety rules (7)5.The Operation Procedures for SEM and EDS analysis (9)5.1 Operation procedures for SE (secondary electron) imaging (10)5.2Operation procedures for BSE (back scattering electron) imaging (13)5.3 Operation procedures for STEM (Scanning TEM) imaging (14)5.4 Operation procedures for EDS analysis (15)1. Summary of the specifications of the JEOL JSM-6701F SEM with EDS system2. IntroductionThese Standard Operating Procedures (SOPs) provide the information on both the procedures for operating the JEOL JSM 6701F scanning electron microscope (SEM) and the lab safety issues associated with the SEM operations and sample preparation. In the SEM lab, a detailed user’s manual is also available which covers the basic principles of operation, equipment design, technical information about its key components, as well as control-panel settings. It is suggested that users become familiar with the manual. For all SEM users, before your SEM analysis independently, it is required that you should be familiar with the standard operating procedures (SOPs) and use them as the primary source for the steps involved in operating the SEM and SEM sample preparation as well as the associated SEM lab safety issues.The operation of a scanning electron microscope (SEM) is based on scanning an electron beam across a sample and detecting electrons ejected from the sample surface. With the interactions between electron and sample, x-rays, auger and secondary electrons as well as backscattered electrons are ejected from the sample surface. The JEOL JSM-6700F SEM has several detectors which enable several imaging modes for different analysis purposes. Also, the SEM is equipped with an Energy Dispersive X-ray Spectroscopy (EDS, JEOL JED-2300) System which can be used for elemental analysis. The details of the SEM imaging modes and the functions of the EDS analysis are shown as follows:A.Secondary-electron imagingSecondary-electron imaging is the most important imaging mode in SEM. Secondary electrons are those emitted from the sample surface following absorption-emission transitions. The low exit depth of secondary electrons (of the order of a few nanometers) allows the highest resolution in SEM imaging. For our SEM, the best resolution that can be achieved is around 1nm according to our primary experimental results. The contrast in secondary-electron imaging mode is mainly topographic contrast which is dependent on sample tilting, surface roughness and atomic number (with contribution from excitation effects of backscattered electrons).B. Backscattered-electron imagingBackscattered-electron imaging is mainly for material contrast. The mechanism behind this is the dependence of the backscattering coefficient on the mean atomic number, which allows the phases with different mean atomic number to be recognized.C. The scanning transmission electron imagingThe SEM is equipped with a transmission-electron detector. For the scanning transmission electron imaging (STEM), the electron beam scans through the sample just like the SEM imaging mode. The difference between STEM and SEM is that the imaging formation in STEM is by transmitted electrons just like TEM imaging.D. Energy dispersive X-ray spectroscopy (EDS) analysisAn instrument which collects x-rays emitted from a sample which has been bombarded by electron beam. The x-rays are sorted by energy levels, and a spectrum of x-ray energy vs. counts is plotted which is indicative of the elements present in the sample and of the concentration of each element present.The SEM is equipped with the JEOL JED-2300 EDS System with a resolution of around 136 eV. The collection and quantification of spectra are computer controlled with an integrated software. Different elemental analysis modes can be achieved, such as spot, line and area analysis modes with digital mapping function.3. Materials CompatibilitiesMaterial compatibility issues should be considered for SEM analysis, especially for those samples which are beam sensitive such as biological samples. Most conductive or semi-conductive materials can yield satisfactory imaging quality.The SEM works with a high vacuum system (approx. 10-8 Pa in gun chamber and 10-5 Pa in specimen chamber), contamination of the specimen chamber and load lock should be avoided in order to ensure good vacuum condition and analytical performance of the SEM.Therefore, to avoid the contamination of the instrument, please ensure(i)the SEM samples are well dried;(ii)powdered samples are well mounted by using carbon tape and excess amount of powders should be blown away. This is especially important for magneticpowdered samples;(iii)biological samples and other samples containing appreciable amounts of organics, should be well dehydrated, dried and further coated with conductinglayer. These beam sensitive samples should be imaged using low workingvoltage and small probe current;(iv)to use powder-free gloves when handling any samples and/or parts so as to keep finger print oils off the parts and/or sample which will be introduced intothe SEM sample chamber.4. SEM Lab Safety4.1 Personal Protective Equipment (PPE)According to the department safety regulations, all SEM users are required to be properly attired and wear proper PPE - lab coats and safety goggles when working in the SEM lab. In the SEM lab, there are different working zones in which users are required to wear the proper PPE, as shown by the image below.(i) Red-line marked zone I:The zone is near the facilities for the SEM sample preparation. Users are required to wear both lab coat and safety glasses when working in this zone;(ii) Red-line marked zone II:The zone includes the areas behind, and on the left/right of the SEM. This zone is set for some maintenance work by engineers and the person-in-charge; Users arenot allowed to enter this zone;(iii) Yellow-Black line marked zone III:The zone is set for user to operate the SEM. Users are required to wear lab coatwhen working in this zone.4.2Risk AssessmentBefore SEM training/practice/analysis, all SEM users are required to submit the detailed Risk Assessment for the SEM samples and SEM analysis. The Risk Assessment should be duly signed by supervisors;Please update the Risk Assessment of your samples if your research project is changed. We may inspect your samples frequently.4.3 The replacement of oil mist filter of the rotary pumpsThere are two rotary pumps in the SEM lab. One is for the SEM and the other for the sputter coater. For safety and health consideration, the oil mist filters for these two pumps need to be replaced every 2 years. The replacement work will be done by JEOL engineers.4.4 Safety issues related to the SEM samples and sample preparation:(i)Users are not allowed to bring chemical solutions/solvents to the SEM lab forSEM sample preparation. If samples are suspension solution, users shouldmount/fix their samples on the specimen mount or stub in their own researchlab first before performing the sputter coating and/or SEM analysis;(ii)Do not leave SEM samples in the SEM lab after analysis. All the samples should be taken out from the sample holders and brought back to their ownresearch lab;(iii)As high risk samples need to be handled in a safe place such as fume cupboard, users should mount/fix their samples on the specimen mount orstub in their own research lab first before performing the sputter coatingand/or SEM analysis;(iv)Users should be careful around the sputter coater to avoid hazards inherent in such a vacuum device. (e.g., implosion of glassware/plastic under highvacuum). Therefore, users are required to wear safety glasses and lab coatwhen operating the sputter coater;(v)To avoid any unnecessary contamination to the parts which will be put in the SEM chambers, users are required to wear powder-free gloves when handlingthe specimen holders and stages;4.5 Other lab safety rules(i)Liquid N2: The person-in-charge of the SEM is responsible for LN2 top up ofthe EDS Dewar. SEM users are not allowed to handle liquid N2. If users encounter any problem with the EDS analysis, report it to the person-in-charge immediately;* For person in-charge of the SEM: It is necessary to wear cryogloves, lab coat and safety glasses when handling LN2.(ii)N2 gas cylinder: The gas cylinder is under high pressure and should be firmly secured to a large immovable object. Mishandling gas bottle can cause severe pressurized damage and/or injury. The person-in-charge of the SEM is responsible for changing the N2 gas cylinder. Users are not allowed to handle N2 gas cylinder and gas regulator. If you find that the pressure is insufficient, please report it to the person-in-charge immediately;* For person in-charge of the SEM:∙The N2 gas cylinder should be firmly secured to the wall;∙The N2 gas cylinder should be replaced before the pressure is lower than 75psi. Before replacing the cylinder, close the main valve of the cylinderfirst and then fully turn counterclockwise the pressure-adjusting knob ofthe pressure regulator. This is to keep a certain level of pressure insidethe tube connecting to the SEM; otherwise, the vacuum system of the SEMwill automatically shut down;∙After a new cylinder is secured and the pressure regulator is connected, stand behind the pressure meters before you open the main valve of thegas cylinder;∙Turn on the main valve of the cylinder and adjust the supplying pressure to the desirable level as marked by the dark arrow in the pressure meter(75psi).(iii)The SEM is working with a high-voltage system, SEM users should avoid touching conductors, and should observe and report any damage to electrical insulation or other damage to the instrument;(iv)No food and drinks in the SEM lab;(v)The SEM must be checked regularly for x-ray leakage.5. The Operation Procedures for SEM and EDS analyses5.1 Operation procedures for SE (secondary electron) imaging5.1.1 System checking before analysis1)_ Check if monitor is ON.2)_ Check if PC is working.3)_ Check if PCSEM software is running.4)_Check if stage is at exchange position (X = 35, Y = 25, R = 0, Z = 8, Tilt = 0 ).If not, (i) click “Exchange”or “Home” icons as circled in above figure to neutralize X and Y motor control stage; (ii) move manually Z stage to “8.00 mm” and Tilt stage to zero. Exchange indicator on the airlock should be lighted.5.1.2 Specimen loading (you are required to wear gloves during loading)6)_ Mount specimen in a specimen holder and adjust specimen height at same level as specimen holder (if possible).7)_ Select in PCSEM software the specimen holder you are using by clicking the icon as circled in the figure below (for stage safety).8)_ Press airlock “Vent” button and the button will be flashing. Wait till the button stops flashing, and then open the airlock, i.e. specimen exchange chamber.9)_Mount the holder (with specimen) on the specimen exchange stage and then lock the airlock.10)_ Pump the airlock by pressing the “Evac” button which will be flashing during the pumping. Evac sequence is completed when Evac button stops flashing.11)_ When Evac button stops flashing, load specimen holder on the stage by pushing straight forward the exchange rod with holder on the stage. Holder indicator should be lighted. If microscope has an optional infrared camera, sample holder will be visible.* Please handle the exchange rod slowly and gently during the specimen loading.Users should follow the operation procedures as highlighted in the SEM training.Improper operation during loading will lead to damage of the exchange rod and vacuum leakage, causing serious accidents.For the specimen loading, the detailed procedures are:(a) After ensuring that “Evac”button stops flashing, stand a little aside andslowly and gently put down the exchange rod;(b) On reaching the horizontal position, hold the end of the rod so as to let it slidein slowly. Never press, tilt or rotate the rod during this operation;(c) Place your hand at the end of the exchange rod so that you can push it straightforward into the chamber. Never press, tilt or rotate the rod during this operation;(d) With successful loading, the button “HLDER” will be lighted;(e) Pull the exchange rod straight out until the end of the pipe of the rod goesout of the guide (Failure to do so will damage the exchange rod which is costly, around S$10K). Tilt up the rod and lock it. Never press, tilt or rotate the rod during this operation.13)_Press the airlock “Vent” button to vent the airlock. This is to ensure the safety of the vacuum system.14)_Click the icon “PVG” on the top menu of the window as circled in the figure below:A small window will pop out as shown in the figure below. The value indicates the vacuum in the specimen chamber.15)_ Wait till the vacuum in the specimen chamber is 9.63E-005Pa or at least1.91E-004Pa (Please ensure the sufficient drying of your sample before SEM analysis. Wet samples will prolong the pumping time. The pumping time will also be included for the usage charge). During the pumping, check the colour of HT icon , figure below [Black = vacuum not ready, Blue = vacuum ready (user to confirm that the Penning Gauge reading is 9.63E-005Pa or at least 1.91E-004Pa) and HT ready, Green = HT ON].5.1.3 Imaging and recording16)_ SEM parameter checking:(i)Working HT is set at 5 kV (5kV is enough to ensure good resolution.Please do not change HT value by yourself as the alignment is onlyadjusted properly at 5kV.);(ii)The probe current has been set at 10uA and you are not allowed to change it;(iii)The working distance (WD) is set at WD = 8 mm using LEI and SEI detectors (SE imaging); For BSE imaging analysis, the WD is set at 10mm.17)_Ensure that the vacuum in the specimen chamber reaches 9.63E-005Pa, and then apply HT by clicking HT icon to Start Gun emission . Then wait until the emission current has reached the preset value of around 10 µA.18)_ Adjust focus, stigmators X/Y, contrast and brightness (ACB (auto contrast and brightness) can be used).19)_ To collect an image, select a slow scan speed (Fine View button), and press Freeze button to keep the image in memory (Freeze frame mode in Instrument Operation menu).20)_ Press Image File Handling Icon and Save or Export image in a selected folder.5.1.4 Specimen unloading (you are required to wear gloves when handling the sample holder)21)_ Switch OFF HT by clicking on HT button. HT button will be blue.22)_ To remove sample, recall stage exchange position (X = 35, Y = 25, R = 0, Z = 8, Tilt = 0) by clicking “Exchange”or “Home” icons as illustrated in 4), and move manually Z to 8 mm and Tilt to 0° for 3 axis motor control stage.23)_Press the airlock “Evac” button and wait till the “Evac” stops flashing.* Please handle the exchange rod slowly and gently during the specimen unloading. Users should follow operation procedures as taught in the SEM training. Improper operation during unloading will lead to damage of the exchange rod and the vacuum leakage, causing serious accidents. For the specimen unloading, the detailed procedures are:(a) After ensuring that “Evac”button stops flashing, stand a little aside andslowly and gently put down the exchange rod;(b) On reaching the horizontal position, hold the end of the rod so as to let it slidein slowly; Never press, tilt or rotate the rod during this operation;(c) Place your hand at the end of the exchange rod so that you can push it straightforward into the chamber. Never press, tilt or rotate the rod during this operation;(d) Pull the exchange rod straight out until the end of the pipe of the rod goesout of the guide (Failure to do so will damage the exchange rod which is costly, around S$10K). In this case the button “HLDR” will become dim. Tilt up the rod and lock it. Never press, tilt or rotate the rod during this operation.24)_ Push airlock Vent button and remove the specimen holder. Close airlock chamber.25)_ Pump down the airlock by pressing airlock Evac button. Keep airlock always under vacuum.5.2 Operation procedures for BSE (back scattering electron) imaging1)_ Follow steps from 1) to 15) in section 5.1 for specimen loading.2)_Ensure that HT is off.3)_Set the WD at 10.00 mm and tilt control at 0o.4)_Click the RBEI icon as shown in the figure below, which has a grey background on the tool bar.The retractable BE detector is automatically inserted in three to seven seconds, and the background of the icon will become green.5)_Switch on HT .6)_Search for the area of interest by using SEI or LEI detector.7)_ In SEI or LEI mode, adjust focus, magnification, stigmators X/Y, contrast and brightness (ACB (auto contrast and brightness) can be used).8)_Click image selector as shown in the figure belowA menu will pop up. Select COMPO for composition imaging and TOPO for topographic imaging.9)_Press FINE VIEW button on the operation panel to set a low scan speed for imaging. Further adjust focus and magnification, etc.10)_ Collect and save images as for SE imaging;11)_To stop BSE analysis, OFF HT first and click icon to retract the BSE detector.12)_Follow steps from 22) to 27) in Section 5.1 for specimen unloading.5.3 Operation procedures for STEM (Scanning TEM) imaging1)_Follow steps from 1) to 4) in Section 5.1 for system checking.2)_Mount the specimen on the specific STEM holder.3)_Follow steps from 6) to 15) in Section 5.1 for specimen loading.4)_STEM imaging:Please seek help from the person-in-charge for instrument alignment;5)_Imaging and recording;6)_ 12)_Follow steps from 22) to 27) in Section 5.1 for specimen unloading.5.4 Operation procedures for EDS analysis1)_ Follow steps from 1) to 15) in section 5.1 for specimen loading.2)_Check whether the program “Analysis Station’ is running . If not, run the program, as shown in Figure 1.Figure 13)_ To make sure that that the SSM ratemeter (1, Fig 1) is always displayed, place the mouse over SSM Dead Time (2, Fig 1) and select “Show Monitoring window”.The recommended values for SSM Ratemeter for spectrum acquisition are:T1 : not recommendedT2 : Deadtime 3%, Count Rate 2500 cpsT3 : Deadtime 13%, Count Rate 2500 cpsT4 : Deadtime 23%, Count Rate 2500 cps (highly recommended)The recommended values for SSM Ratemeter for digital mapping are:T1 : Deadtime 2%, Count Rate >3000 cpsT2 : Deadtime 4%, Count Rate >3000 cpsT3 : Deadtime 15%, Count Rate >3000 cps (highly recommended)T4 : not recommended1) SSM Dead Time 2) SSM 3) Condition SettingIf the value of SSM ratemeter is too small, do the following adjustment:(i) Change the working distance (WD) to 15mm;(ii) Increase HT to 15 kV step by step with 5kV/step;(iii) Increase the probe current till SSM ratemeter value reaches a desirable level.4)_Image and Spectrum Acquisition:Figure 3a) Always check your SSM Ratemeter readings so that you have enough count rate to carry out spectrum acquisition.b) When you have located the area that you are interested to do analysis, capture the image by clicking Image (1, Fig 3). If you decided not to keep this view, you may d elete it by selecting the view, go to Edit, and select “Delete View”.c) To perform a spot analysis on a single spot, position your mouse at the spot, right-click the mouse, to select the spot. The acquisition of spectrum will start with the setting that you have set previously under Single Spot Acquisition condition.d) Once the acquisition is stopped, you can continue to review and analyze the spectrum. 1) Image AcquisitionFigure 4e) First, click Qual. (1, Fig 4) and the spectrum will be automatically labeled. However, if some smaller peaks are not being labeled, you can manually label the un-labeled peaks by clicking Ident. (2, Fig 4), then left-click your mouse at the un-labeled peaks. The list of all possible elements at the peak position will appear (3, Fig 4), and you can choose the most probable elements by selecting Registration.f) You can adjust the position and height by selecting one of these icons (4, Fig 4). The name of the spectrum can be re-named in Memo (5, Fig 4).g) You can also manually label or unlabel elements from the periodic table by selecting Ptbl. (6, Fig 4). Just click on the elements, when it is red, it is selected. When it is grey, it is deselected.Figure 51) Auto Identification 2) Manual Identification 3) Manual List of elements 4) Spectrum position &height 5) Spectrum 7) Quantitative analysis 8) Report 6) Periodic table selecte d Notselectedh) To perform quantification, click Quant. (7, Fig 4). The following page appears.Figure 6The parameters that you can select are:Quantitative Method: ZAF (for mixture of heavy and light elements, default)Phi-rho-z (for all light elements only)Ratio (for TEM use)Quantitative Mode: Standard (users build up own set of standards)Standardless (quantification based on standard data built-in, default) Calculation Method: Pure (quantification based on pure elements, default)Oxide (quantification based on oxide state, only for oxide samples) Normally, when we review the data, we refer to mass%, which is more commonly used to reflect quantification results. Also, the Error% is an important number that shows the accuracy of quantification. Normally, if Error% is higher than mass%, you should be doubtful about the presence of the elements, either it is too small in content, or it is not present.Another result possible is the atomic %, which shows the ratio of elements present as atoms. For example, CaCO3 will give mass% of Ca: 40%, C:12%, O:28%, while the atomic% will be Ca: 20%, C:20%, O:60%.i) Finally, to generate the report, you can click on PView (8, Fig 4) on Figure 4. Thefollowing page appears.Figure 7j) You can then print out the data by selecting Print.5)_Digital Mapping:a) To perform digital mapping on the sample, first acquire an image, then select Mapping. The following page turns on:Figure 8b) During the process of mapping, you can always add in or remove any elements through selection of individual elements in the periodic table (1, Fig.8). When you remove an element, just de-select it from the periodic table, and the mapping for that element will disappear. When you want to add another element, select it in the periodic table, then a blank mapping window will be added. To reveal the mapping data, press the Play button (2, Fig 8).c) The default color display for the mapping data is in quantitative mode, where red is higher in concentration, while blue is in lower concentration. However, you can change the color to mono tone. Go to Tool, Edit Element Palette, and the Edit Palette page (Fig 9) will turn on. Select Auto (1, Fig 9) and press Apply Now (2, Fig 9). All the mapping images will be automatically changed to a single color, and sequence will be in Red, Green, Yellow, Magenta, Blue, Red, Green ……d) If you prefer to fix the mapping color of a particular element, for example, you want Si to be always in Red, you can do so by first selecting Si on the element table (3, Fig9), right-click on the color scale and select Change Color (4, Fig 9). A color palettewill appear and you can select the color that you want. After you have finished the 1) Periodic Table2) PlayButtonselection of all the elements, please remember to save it. If not, one click of the Reset button will automatically reset the color back to the default values.Figure 9e) Once mapping has been done on your sample, you can extract spectrums from anywhere in the image. This is achieved by selecting the Popup Spectrum (1, Fig 10).Figure 103) Element table 1) Auto 2) Apply Now 4) Change Colour1) Popup Spectrum 2) Areaselectionf) You can select the area that you want to extract the spectrum from, by selecting oneof the option in area selection (2, Fig 10). Then draw the area on the mapping data and the EDS spectrum will be displayed.g) To print the mapping data, go to File, Print Setup, and the following page appears(Fig 11). Go to Map/Thumbnail, and select the total number of mapping images you would like to have on one page. Click OK, and the page will close. Now go to File, Print Preview, and the mapping data will be organized in one page (Fig 12), and you can proceed to printing it, or saving it into a jpeg file.Figure 11Figure 12。