SmartSoft AES Operator s Guide

Transcription

1 SmartSoft AES Operator s Guide Part No Rev. A Physical Electronics USA, PHI, SMART-Tool, SmartSoft, MultiPak and Watcher are trademarks of ULVAC-PHI, Inc. All other trademarks are the property of their respective owners.

2 Introduction The PHI 700 AES is operated using three software packages 1. SmartSoft-AES for primary operation of the system including, sample into and extract, stage navigation, SEM Imaging, Auger Analysis and Ion Gun Control 2. Watcher for System Vacuum Control Interface 3. Multipak for post acquisition off-line data reduction and output SmartSoft-AES SmartSoft-AES is a windows based interface with five primary tabs along the top devoted to different tasks 1. System, for loading and unloading samples 2. Sample, for navigation and sample Z-Alignment 3. SEM, for adjusting and outputting SEM Images 4. AES, for acquiring Auger Surveys, Line Scans, Depth Profiles and Maps 5. Hardware, for control of the Ion Gun used for sputter cleaning the sample surface, depth profiling and charge neutralization Watcher Watcher is opened automatically when SmartSoft is started. Watcher runs in the background and is interfaced through the SmartSoft System tab. One does not typically perform any functions directly from the Watcher Window. Multipak Multipak is a Matlab based data reduction software package that runs Off-Line. It handles both PHI XPS and PHI AES data files.

3 Badger The Badger laboratory access program is used to reserve time on the PHI AES instrument and to enable the instrument at the start of your session and disable the instrument at the end of your session. It can also be used to Flag instrument problems or Shutdown access to the instrument in the event of a critical instrument problem. The Auger_SNL instrument tab in Badger is found under the SNL tab and in the subheading for Surface Analytical Lab. Once AES-SNL is enables, the SEM video monitor will turn on allowing you to locate your sample in the SEM Image.

4 Vacuum System The condition of the Vacuum system can be checked on the gauge control display in the top of the left hand electronics chassis. The top reading is the ion gauge at the upper column where the electron gun filament is located. It should always be in the low E-09 range. The Lower set shows three readings. The top of these three is the ion gauge in the main analysis chamber. When the instrument is idle, it will show in the low E-09 to low E-10 range. It may come up to mid to low E-08 during some analyses. The middle reading is a convectron gauge in the main analysis chamber and if the main chamber ion gauge reads in the listed range, the convectron gauge will read 0.0 E-0.

5 The third of this set is the convectron gauge in the intro chamber. It will read 0.0E-0 when the intro is pumped out and will read ~780 when the intro is vented to put in a sample.

6 Intro Sample This procedure describes introducing the samples into the analysis chamber. Load the samples to be analyzed onto a PHI sample holder at the sample prep counter. Click the System session tab along the top of the SmartSoft user interface. The Sample Transfer application is displayed on the top right hand side of the SmartSoft System window. Follow the Intro Sample flow. Click the Backfill V2 button. This will close the V3 Intro Pumping valve and Open the V2 valve to fill the Intro with Nitrogen gas. The convectron gauge in the intro chamber will come up to ~780 torr and the cap can be removed from the intro chamber and the sample holder mounted on the fork on the sample transfer arm. Replace the cap and click Pump V3 to pump out the sample intro. This process takes just under 5 minutes. A message in the lower left hand corner of the SmartSoft System tab will say Vacuum: pump into started and the mouse will have the hourglass icon. After three minutes, the mouse will return to the normal pointer icon and the message in the lower left corner of the System tab will display Vacuum pump intro complete.

7 Click the third button (intro sample) in the Intro Sample flow. The stage will move to the intro position. V1 will open and a message box will appear. Smoothly slide the Introduction rod into the chamber all the way to the fully inserted position. Click the OK button in the message box. The stage will move up to engage with the sample holder. Watch through the glass window in the main chamber to make sure the stage engages properly with the sample holder. A new message box will appear. Retract the sample introduction rod all the way out to the stop. When the arm is retracted, V1 will automatically close. Click OK in the message window. Sample Introduction is Complete.

8 Locating Sample Click the SEM session tab along the top of the SmartSoft user interface. Use the pull down menu in the upper right side of the SEM session tab to choose the 1kV 1nA beam file and click load. The Electron Gun Control box in the right hand electronics chassis will display the beam energy. Use the Field of View pull down menu to choose the largest field of view (5000mm)

9 You can look through the glass window in the main analysis chamber to see where you are located on the sample holder and use the X, Y map on the instrument and the X, Y map on the SEM Monitor to determine which direction to move to sample of interest. Using the mouse and clicking on a point on the image will bring that point to the center of the field of view. Using the mouse to draw a box on the image will zoom in and center that box in the field of view. To Zoom out again use the Field of View pull down menu and choose a larger size.

10 Z Align Once you have found the sample of interest, click the Sample session tab along the top of the SmartSoft user interface. Click the Z Align application along the right hand side of the Sample session window. A Z Align flow will be displayed. The first icon will move the stage back to the center of the sample holder. You typically do not want to use this button. Click the Z Align button in the Z Align flow to start the Z align process. A window will appear showing the elastic recoil energy of the primary beam.

11 For a typical sample, the introduction position will be low and the sample stage will need to be raised to bring the elastic recoil peak up to the desired setting. The proper Z height for a blank sample holder is ~ 16.5mm. Therefore you can estimate the proper Z height of your sample from ( Proper Z = 16.5 your sample thickness) Enter this number into the Z position in the display window and click Drive Z. The elastic recoil peak will move closer to the green center line. At this point fine adjustments to the Z height can be made with the keyboard up/down arrow keys, or the up/down stage tab in the display window. Move until the recoil peak centers on the green line. At this point, click the Close button in the bottom corner of the display window. For similar samples close together on a small holder, this Z position should be good for the full sample set. If the samples are different substrates or spread far apart on the large holder, it is a good idea to redo the Z Align whenever moving to a new sample.

12 Setting Electron Gun for Analysis The 1 kev 1 na beam is used to locate the sample of interest and to do the Z Align, but you cannot get meaningful AES data with only 1 kev primary electrons. The most common starting setting for AES analysis is 10 kev 10 na. Go to the SEM session tab at the top of the SmartSoft user interface. Use the pulldown menu for SEM Settings in the upper right hand corner of the window. Chose the 10kV10nA file and click load. The electron gun supply in the electronics chassis will display the chosen beam energy. Zoom in on a feature on the sample to set the focus and stigmation to get the best image.

13 Course Focus and Stigmation are located in the upper right had corner of the SEM settings window. Fine focus is done by means of a focus know on the electronics chassis just below the electron beam control.

14 It is good practice to find a feature and focus at a higher magnification that intended for the analysis and then zoom back out to the desired magnification for the analysis. At any time you can save an SEM image to your user directory (see setting user directory in following AES Tab section) by clicking the Camera Icon in the SEM session. AES Tab The AES session tab is used to set the user directory to store the data and to set all the acquisition parameters and acquire data. User Directory Click the AES session tab at the top of the SmartSoft user interface. Click the Data Manager application tab along the right hand side of the AES session, and the Directory tab in the upper right corner of this session. Every user creates their own Main data directory under C;\Datafiles\Users. You can then create subdirectories however you wish to sort your data. Create a new directory or highlight an existing directory under the C:\Datafiles\Users data string and click the Set Acquisition Directory Icon just above the directory string list. This will set the destination directory of all data acquired during your session. Set a file name and file number by clicking the Properties button at the bottom right corner of this session. A Data Manager Properties window will open. Click the Lab Book Tab at the top of this window. Type a file

15 name and start number for your data. The file number will automatically increment for each saved file. To change the name for a new sample, return to this window between each sample. Click the Close button at the bottom of the Data Manager Properties window.

16 Survey An Auger survey is a quick, high sensitivity acquisition of Auger data over a wide energy range. A survey is used to identify elements present in the analysis area. Under the AES session tab and select the Survey application tab along the right hand side. Select Survey in the top right hand corner. Enter the Starting ev, Range, ev per step and cycle number in the setup. Check the status of Image Registration (typically this is Off for low magnification analyses. See later section for Using Image Registration). Before starting the acquisition, you must set the points or areas on the sample that you wish to survey. In the AES Session, click the Analysis Area button in the top right section of the Survey window. A list of points and areas will be displayed and the points and areas will show on the SEM image. Points and areas can be added or removed. Existing points and areas can be moved by dragging them with the mouse in the SEM image area. Clicking the mouse in an open area of the SEM image will add points while in this tab. Once all the areas of interest have been defined, click the Survey button at the top of this window and then click Survey to start the acquisition.

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18 An Acquisition Status window will appear showing how many points/areas are being analyses, number of cycles for the full analysis, and current point and cycle of the acquisition. If left, the system will complete all the requested points and cycles and automatically save the data in the designated acquisition directory. Clicking the Abort button in the bottom of this window will stop the acquisition and no data will be saved. Clicking the Stop button in the bottom of this window will set the system to complete the current cycle being run and then stop and save the data.

19 Line Scan An Auger Line Scan is a series of data points collected along a horizontal or vertical line across an area of the sample. In the AES session click the Line Scan application tab along the right hand side. In the upper right hand portion of the line scan setup window you choose the 2 point, 3 point or window mode of acquisition and the point resolution of the line scan. In the lower portion you select the specific element energy transitions that you wish to monitor in the line scan. A full survey cannot be done in Line Scan Mode. Clicking Analysis Line along the top of the line scan setup window allows you to choose the line (Horizontal or Vertical) and position the line in the SEM Image.

20 Click the test acquire icon to open up the test acquire window where you set the position of the window, 2 point or 3 point peak and background regions to be used for each element monitored in the line scan. In 2 point mode for example, the two red lines are centered about the element peak and the two blue lines are set around the background near that peak. The width of the lines is fixed. This width is based on the detector resolution at that energy. During a test acquisition, the test point is displayed in the SEM image. You can move the test point to be acquiring from an area that contains the element of interest.

21 Maps An AES Map, like a Line Scan, steps the beam over a specific area of the sample while monitoring the peak and background of specific elemental energy transitions. The map area is defined to be what is shown in the SEM field of view. Acquisition Mode, Image Resolution, Elements monitored and Test Acquisition are the same as in Line Scan. In addition to Stop and Abort in the Acquisition Status Window, a Next Element Button also appears. Clicking the Next Element, will cause the acquisition to finish the current frame for the current element, and then move on to the next element. In the Map session, clicking the Stop Button will cause the acquisition to finish the current frame of the current element and then stop and save the data without going on to the remaining elements.

22 Ion Sputtering An Argon Ion gun can be used to sputter the surface of the sample. This can be used in a Timed Sputter to remove surface material prior to doing the next set of data acquisition, or can be used in a Depth Profile to alternate between sputtering the surface and collection Auger Data. To turn on the argon ion gun, go to the Hardware Session Tab, choose a preset ion gun file from the pull down menu and click the Standby Button. This will automatically start the differential pumping of the ion gun, open the argon gas leak, and turn on the ionizer filament. It is best to let the gun warm up for about five minutes so the filament and gas pressure are stable. Prior to sputtering, click the Blank button. You can manually sputter the surface for a set time by entering the time in the Sputter Time Field and clicking Timed Sputter. The ion gun will use the conditions of the chosen beam file and sputter the sample surface for the set amount of time. At the end of the set time, the ion gun will return to the Blank state, and further Auger Analyses can be performed. You can pause the sputtering by clicking the Timed Sputter button before the countdown reaches the end.

23 The argon beam can also be used in a Depth Profile mode, where you alternate between sputtering the sample to expose a fresh surface and acquiring data from selected elements of interest. In the AES Session tab, choose the Profile tab. Analysis Mode, Elements of Interest, Test Acquire are all set up the same as in a line scan or a multiplex. You can also import set elements from one analysis type to another such as setting up a line scan and then using the same element set in a depth profile. In addition to the analysis mode and element list, in a depth profile you set the total Sputter Time for the profile and the Sputter Interval for how long the beam sputters between each acquisition cycle. There is also a delay setting which allows the sample to stabilize after the ion gun is blanked before the Auger data acquisition begins. 2 to 3 seconds is a typical delay time. The acquiring depth profile data is displayed as electron counts versus sputter time for each element. If you are doing a 2 Point Acquisition Mode (Peak Background), due to the slope in the Auger Background spectra, a negative number may appear if the element of interest is not detected. Multipak is set to treat negative numbers as zero, so that no negative concentrations can appear.

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25 When you are finished using the ion gun on the sample set you have loaded, the ion gun is turned off by clicking the off button in the ion gun menu under the Hardware session. This will shut down the filament, turn off the argon gas flow and stop the differential pumping of the ion gun. You then need to go back to the system tab and click the pump button in the extract sample flow chart. Image Registration When running a high kv beam file and/or a very small field of view for fine features, the acquisition area may move over time due to beam drift. Image registration saves a reference image of a feature in the field of view. During the analysis, a live image is checked against the stored reference image and the registration will automatically compensate for beam drift. In the AES session, click the Image Registration application tab along the right hand side. We typically only use the 1 point registration. Two point is really only needed if sample rotation is used during a Zalar Rotation Depth Profile. It is best if the field of view of the reference image matches the field of view of the analysis. Click the 1 button in the image registration flow chart. A double box will appear on the SEM image that defines the reference image. This can be moved or the size changed using the mouse in the SEM image. Position the box around a distinct and well defined feature in the SEM. Once positioned, click the Save Image button in the image registration flow chart. Now in any analysis setup, you can click the Image Registration On button and select the registration interval. You can click the Register Image button in the image registration flow chart to test the registration prior to starting the analysis. If you move to a new area of the sample, you either need to click the image registration Off button, or return to the Image Registration setup and redefine a reference image before starting the next analysis.

26 Shutdown / Extract Sample If the ion gun had been used during your analysis, go to the Hardware Session and in the Ion Gun Settings tab, Click the Off button to turn off the ion gun filament, close the Ar gas leak and stop the differential pumping of the gun. Go to the System Session and in the Extract Sample Flow, click the Pump Intro icon. Go to the SEM session tab and in the SEM setting tab, choose the 1keV, 1nA beam file from the pull down menu and click the Load button. Go back to the System session. If the Pump button had been clicked in the Extract Flow, make sure the message in the lower left corner indicates Pump Intro Complete. Click the Extract icon in the flow. The stage will move to the extraction position and the V1 gate valve will open and a message will appear

27 Smoothly slide the arm into the main chamber and watch that the fork slides onto the bottom of the sample holder. Click OK. The stage will drop, releasing the sample holder and the message will appear Smoothly slide the arm all the way out of the chamber. The V1 gate valve will automatically close. Click OK. Click Backfill in the Extract Sample Flow When the Intro Convectron Gauge reaches 780 torr, you can remove the cap on the intro chamber and remove your sample holder. Replace the cap on the intro chamber and click either Pump button in the Intro or Extract Sample flow. Watch the convectron gauge to make sure the system pumps down. Turn off the light in the main chamber and disable the instrument in Badger.