Electron Microscopy Centre
Contents
1. Electron Microscopy Centre Title RUNNING Backscattered Detector BSD ON LEO 1450VP SEM Equipment LEO 1450VP SEM Equipped with BSD Revision 1 0 Effective Date 20 11 2005 Author X Yang Warning Before you attempt to operate this equipment for the first time please make sure you are aware of the precautions that you must take to ensure your own safety Working Environment Do not use electrical equipment in e Rain or excessive moisture environment e The presence of flammable or explosive gases The equipment is not designed to be water or splash proof or to be used in area where there are flammable or explosive gases or fumes HIGH VOLTAGE Running BSD on the SEM Basic Instructions Logon LEO 1450VP user interface Check the BSD detector to make sure it is in the position to use If it is not contact lab staff 3 Load your specimen and standards please wear provided powder free gloves only 10 11 12 13 Turn on the filament and set accelerating voltage to desired operating conditions if not sure set 20kV The default detector has been set to collect secondary electrons You can now work on obtaining a sharp image using stage position focus stigmators image brightness and contrast Set the working distance to desired value and adjust the spot size If you have found an interested spot switch to BSD detector The system will switch to BSD imaging mode Adjust the bright2. Work on obtaining a sharp image using stage position focus stigmators image brightness and contrast The default detector SE1 has been set to collect secondary electrons You can now work on obtaining a sharp image using stage position focus stigmators image brightness and contrast In order to get an image you will have to adjust the focus contrast and brightness It is always a good practice to start from a low magnification such 30x 50x and switch to higher magnification SEM Control You could focus the image by selecting Detectors Scanning Vacuum focus mg mode and turning the FOCUS aan iii stage xaa BMW 3126 knob In this case the working distance WD 1100 0 um physically remains but the electron beam ae ETN focus on different level to match the WD The nares fibbie metuda T a WD value becomes REAL only when the m beam is well focused on specimen Best Aperture Yes Mag i Focus Auto Sat Aito Altar You could also focus by changing the Z Emission Stigmation Shit Ti position of your sample this is the physical distance between the sample holder and the pole piece the tapered column that hangs f above your sample BE CAREFUL You a might inadvertently ram your sample into the Depth hore pole piece Therefore you may want to switch on the infrared camera TV mode so Fill Target 3 6004 that you can pay attention to how close your sample is from th
3. do is to load your sample Please make sure the filament has been turned off at least 30 minutes so to increase the lifetime the filament Do this by right clicking on the Vac button in the bottom right corner and select Vent button at the popup widow This will vent the sample chamber and allow you to open the sample chamber door It will take approximately 5 minutes to balance the pressure within the sample chamber with atmosphere Never pull the door during the 5 minutes venting period another detector EDS has a fragile and expensive window a sudden pressure increase in the specimen chamber would likely damage the EDS window EENAA ME Contrast 50 0 Macro Idle M Vac y Fi X EHT gt lt Never reach into the sample chamber without gloves on Always use the sample exchange tool tweezers and special designed screw driver to switch your sample with the one that is already in the chamber Put the sample you just removed into covered box to prevent the dust If you are not familiar with the sample exchange procedure or how the sample stubs fit onto the stage please ask for help WARNING Any bare hand operation during the sample loading unloading may result in loss of privilege of using the system Once your sample is secure on the stage and positioned approximately where you want it close the door latch it and right click the Vac button on the computer then select Pump to begin the pumping process After about 5 minutes th
4. e Vac indicator Hao will shows a ready sign At that point the sample chamber is under vacuum and you are ready to begin viewing your sample It is always a good idea to wait a litter longer until the vacuum reading is approaching 10 torr Stage Manager E3 Stage Manager x Stage Manager Stage Points List tab Stage Properties tab Stage Points List tab Stage Properties tab Stage Points List tab Stage Properties tab Stage Scanningtab Stage Survey tab Stage Scanningtab Stage Survey tab Stage Scanningtab Stage Survey tab Stage Navigation Tab Stage Statustab Stage Navigation Tab Stage Status tab Stage Navigation Tab Stage Status tab Side on Side on Side on This view shows the selected stage sample holder and is side on to the holder The horizontal line shows the sample height parameter m Perpendicular This view shows a perpendicular view to the holder The horizontal Safe stage allocation Simply turn the stage to reach next sample This view shows the selected stage sample holder and is side on to the holder The horizontal line shows the sample height parameter Perpendicular This view shows a perpendicular view to the holder The horizontal beam center line beam center line beam center line is visible when is visible when is visible when Stage Tilt 0 Stage Tilt 0 Stage Tilt 0 Show Fields Show F
5. e pole piece W Beam Blanked Stigmation M Optibeam I Feed certo If you have found an interested spot switch Stigmation While you are still at high magnification and once you have made your final focus adjustments you should adjust the Stigma X and Stigma Y to try to improve the focus slightly Moving between fine focus and Stigma adjustments at high magnification may provide small but sometimes significant improvements to the quality of your image Set the working distance to desired height always focus using stage Z drive and spot SEM Contral ue m L a ET A long working distance of 20 mm or more EHT 0 00 kv will give the best atomic number contrast F Op oooO O O However a working distance between 13 to Beam State Shutdown 15 mm will give the best general purpose M signal 9mm is optimum for acquiring Filament Type Tungsten topographic information ee If Shutdown Log Off to BSD detector The system will switch to SEU ERS ES BSD imaging mode Spot Size 254 El Once you ve found a spot you would like to Fill Target 3 6004 analyze you are ready to switch your image h E g over to the BSD detector Depending on your EHT Target 20 00 kY sample type you may also wish to get o E elemental information from EDS detector please refer to different instruction manual In BSD mode objects with a high atomic number will be brighter where those with low atomic numbers wi
6. he beam and wait for 30 min so the filament is cooling down to room temp 11 Remove specimen from chamber close the door before pumping 12 Log off the LEO user interface In the Menu Bar click on File and Log Off then OK to log off the LEO operation system You can also log off the system by closing the window Reminder you have to log off the LEO system after finishing your research otherwise the computer log system would mistakenly consider you are still using the machine and therefore extra charge may occur due to extended logon time to the system 13 Remember to fill the log book Reference 1 LEO 1400 Series Backscattered Electron Detector Operator s Installation Manual LEO Electron Microscopy Ltd Cambridge England 1999 2 LEO 1400 Series Scanning Electron Microscopes Operator User Manual LEO Electron Microscopy Ltd Cambridge England 1998
7. ields Show Fields Unsafe stage allocation sample 4 5 migh hit detectors when moving This view shows the selected stage sample holder and is side on to the holder The horizontal line shows the sample height parameter Perpendicular This view shows a perpendicular view to the holder The horizontal along Z direction While waiting for the vacuum to be ready adjust the sample stage and locate your first sample under the center of the column In order not to hit on any detectors within the chamber it is always a good practice to move the sample at front end of the stage under the column and rotate the stage to locate your interested one It Is important to remember that the specimen must be flat or not tilted for BSD detection k 4 Turn on the filament and set accelerating voltage to desired operating conditions if not sure set 20kV At this time you should enter your information and the time on into the SEM logbook Set your operating conditions The SEM accelerating voltage should be set to the highest as long as the electron beam does not damage the specimen No electrons will be able to be detected by the BSD at a HV lower than about 4 kV The BSD performance is will increase progressively towards higher HVs If you are not sure you could simply select 20 kV at which you can have Atom No resolution better than 0 1Z between Atomic Number 29 and 30 5
8. ll be darker The QBSD detector provides 4 different 40650 Control configuration viewing modes which could be selected by users User could access the control window by clicking on Tools in the Menu Bar and Go To Panel then 4QBSD Control Two pre defined configurations COMPO and TOPO are available for user to gather surface information Various setting combinations will give various mixes of composition and topographical representations which are given in the table listed below In general high topographical detail will result from selecting a diametrically opposed pair of quadrants and summing them differentially whereas pure atomic number contrast is obtained with all quadrants set to Normal Qi Q 3 Q Function _____ Normal Off Invert Off Topographic illuminated from one particular angle angle obtained in set up above Composition on 1 2 and 3 topographic on and 4 8 Adjust the brightness and contrast if necessary You will have to adjust your contrast and brightness to get a good image You could set the Brightness to 59 and adjust Contrast until an image is seen Then adjust Contrast together with Brightness to obtain the desired image 9 Save the desired image after scanning You could save a desired BSD image under Menu Bar click on File and Save Image then choose the folder you would like to file to be saved 10 When done with collecting image turn off t
9. ness and contrast if necessary Save the desired image after scanning When done with collecting data turn off the beam and wait for 30 min so the filament is cooling down to room temp Remove specimen from chamber close the door before pumping Log off the LEO user interface Remember to fill the log book Running miniCL on the SEM Detailed Instructions 1 Logon LEO 1450VP user interface There are two computers on the SEM but only one keyboard and mouse The monitor for the SEM computer is on the left this is computer 1 The monitor for the EDS system is on the right this is computer 2 The red number on the gray box in between the two monitors indicates which computer the monitor and keyboard are working with If the red number is 2 please switch the keyboard and mouse to computer 1 by simply hitting Ctrl Alt 1 Click on the LEO icon on the SEM computer desktop and logon the software interface using the username and password assigned to you 2 Check whether the BSD is in position When in position for use the BSD detector should be directly below the final lens as shown in the picture Please make sure that the specimen surface is always clear of the BSD diode face to prevent detector damage This could be achieved by limited the value of Working Distance to be 10 mm or higher aF _ _ A 5 f 3 Load your specimen please wear provided powder free gloves only o The first thing you will want to
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