MIMS PROCEDURES. Updated 10 Sept 2008

Transcription

1 Updated 10 Sept 2008 MIMS PROCEDURES A. OPERATING PROCEDURES Tuning...2 Coarse Tuning...2 Fine Tuning...2 Implantation Balancing Trolleys Procedure for Bringing Up New Cesium Source Troubleshooting...5 Checklist for No Signal...5 Wrong raster size or aspect ratio...5 B. MECHANICAL PROCEDURES Sample Loading and Unloading Procedures...6 Loading into SAS chamber (airlock) all valves must be closed...6 Loading Sample from SAS chamber into vessel chamber...6 Loading Sample from vessel chamber to analysis chamber...6 Unloading Sample from analysis chamber to vessel chamber...6 Unloading Sample from vessel chamber into SAS chamber...7 Unloading out of SAS chamber (airlock) all valves must be closed SIMS CCD OFFSET...8 C. CLEANING PROCEDURES General Cleaning Source Unit...10 Cleaning Ceramics for filament connection...10 Cleaning of Metal Parts...10 Intense Cleaning of Metal Parts...10 Cleaning of HT Ceramics...11 D. SOFTWARE PROCEDURES Procedure for loading NanoSIMS 50 software Software - trolleys and preset...13 Setting Trolley Radii...13 To create new preset...13 Implantation...13 Use of the Preset L1=7000V Toggle Switch for High Spatial Resolution Analysis Re-establishing Communication:...14 With Keyboard...14 With NanoSIMS Toolbar How to Retrieve Full Range of Motion in Stage Motors Cutting the Current to Trolley Motors Nikon-to-MIMS Transformation

2 A. OPERATING PROCEDURES 1. Tuning Coarse Tuning Set Raster to 10um field Work with D12 Defocus EOP (+/- 50V from nominal focus) Turn on beam and note counts Adjust C4y (from Q) to maximize counts - If max counts are at +C4y, decrease trolley radius - If max counts are at -C4y, increase trolley radius Put C4y back to 0, then move trolley to maximize counts Repeat with each trolley Check HMR, make sure peak is relatively flat and center line is centered Apply center line voltage (bottom on bottom left side of HMR screen) Fine Tuning Go through coarse tuning procedure except for the HMR steps Record counts. Then put in Entry Slit 3 (Es3), at approx 4.94 horizontal and 5.92 vertical. Record counts EOS to max counts, as well as P2/P3 and Cy. Repeat until counts with Es3 are at least 50-60% of counts without slits. On T3, check Q. Increase and decrease by one bit, taking an HMR every time. Check for lowest L10_90 value (or highest MRP) from HMR, and use that as working Q Move LF4 by 25 bits, check HMR for best MRP Put in Aperture slit 1 (As1), approx 9.45 horizontal and 8.38 vertical, or near there to get max counts. Record counts Run RTI scan to make sure field is homogeneous. If it is not adjust Cy (from L4) to make it uniform Put in energy slit. Vertical first, then adjust horizontal until the signal on T3 is cut by 15-20% Run HMR scans on all the trolleys. Implantation Work with no diaphragm (D10) ~25.5mm Go to RTI, start scan then turn beam on, wait until there is a decent signal Move As1 to ~11.00 mm to block large current from hitting detectors 2

3 2. Balancing Trolleys Set all four trolleys close together, putting T4 at around 330 mm, and the each one 10 mm below the previous one In tuning window, turn scanning mode off Go to the Si grid, adjust the magnetic field to get an Si signal on T4 with C4y=0. Record counts and check PHD If PHD is bad, increase EM4 voltage until you get a good PHD with a nice dip and hump. Peak of hump should be around 125mV-175mV (see daily notes for examples, or PHD binder), Adjust threshold by placing the line at the point where counts begin to increase, and record counts again. If it is good, move on to T3 Change magnetic field to get Si signal on T3 with C4y=0. Record counts and check PHD If PHD is bad, increase EM3 and follow the same steps as for EM4. At this point, counts on Si for T3 and T4 should be almost the same (within 10%) Continue to T2 and T1 and follow the same steps as above. It is more important for T3 and T4 to have about the same counts and T1 and T2 to have about the same counts then trying to balance all four together 3

4 3. Procedure for Bringing Up New Cesium Source When bringing up a new cesium source, patience is the key. It can take up to a few days to fully bring a new source up to working conditions. The main indicators that must be watched while starting a new source are the Source Chamber Vacuum and the Fcp current. The vacuum is especially important. Ideally, it should be in the 10-7 to the 10-6 range. If it gets up to the high 10-5 range (eg 9x10-5), then everything must be put to zero and one must wait for the vacuum to decrease again. First put the vacuum controls in manual mode. This will allow the user to work at conditions in the source chamber around 10-6 or even 10-5 Torr Once the vacuum is down to the 10-7 range, slowly increase the high voltage to the source, by doubling every value, starting at 100V (ie 100V --> 200V --> 400V -->, etc). Keep an eye on the source vacuum and make sure it is at an acceptable value Stop increasing the high voltage at 4000V Start heating the ionizer. Start at 0.1mA. Watch the vacuum as it may increase when the ionizer is started. Once the vacuum stops increasing and drops down to the low 10-6 range, increase the ionizer to 0.2mA. The green light on the source chassis labeled ionizer should now be on Continue increasing ionizer by small increments (ie > > > > etc), always waiting until vacuum stops increasing and begins to drop When the ionizer reaches 0.7 ma, incrementally increase the high voltage to 8000V. Then resume increasing the ionizer When the ionizer reaches about 1 ma to 1.1 ma, let it bake at that current for an hour, keeping an eye on the vacuum. If it is near the end of the day, you can let the ionizer bake at this setting overnight When ionizer value reaches about 1.3 ma, start to bring up the reservoir in a similar incremental manner When the reservoir hits 0.2 ma, the green light on the source chassis labeled reservoir will come on. At this point, there should be some current in Fcp, about a few hundred pa Wait until the vacuum begins to decrease as well as the Fcp current before increasing the reservoir current Incrementally bring the reservoir current up to about 0.3 ma and let it sit there. The Fcp current at this point will be very unstable, so wait until it levels out Final target values for the source are ma for the ionizer, ma for the reservoir, and 8000V for the high voltage 4

5 4. Troubleshooting Checklist for No Signal Sometimes after turning on the beam, there are no counts and nothing showing up on the RTI screen. Usually, the cause is one of the things listed in this checklist. If the machine is working fine and all of the sudden there is no signal after turning on the beam, check all the parameters in this list and make sure they are correct. If, after everything has been checked and the problem continues, the problem may require more in depth troubleshooting. Check Fcp for good primary current Check to make sure L1 is at 0V When the beam is off, L1 is at 1600V. When it is turned on, it should drop to 0V. Sometimes L1 remains at 1600V even though the beam is on. In this case, simply keep the beam on and bring L1 back to 0V. Then turn the beam off and on again to make sure L1 behaves accordingly. Check to make sure EOW is at -8000V In order to have a secondary beam, there must be voltage on the sample. Sometimes when moving the stage around, especially when going from CCD to SIMS mode, the sample voltage will remain at zero. In this case, go to the preset menu, select the small square next to the desired settings, click edit and scroll down to the EOW value, then hit valid. Check vacuum window for high voltage securities and properly opened valves Sometimes for no apparent reason, the software will turn off the high voltage securities somewhere in the machine. If anyone of these securities is off (or displays a red light instead of green), then there will be no signal at the detector level. To solve this, go to the vacuum window and select manual mode. Then enter in the password ims, and enable any high voltage securities that may be disabled or open up any appropriate valves. Check to make sure signal is hitting the detectors Use C4y to move the beam across the detectors to see if there is a signal. The detectors may need to be recentered so the beam hits them directly. Check that all lenses are at their appropriate values, especially EOS, CY, and P2/P3 This is especially important if the slits are in. There can be slight changes in the secondary beam that require a slight realignment using these lenses. As a last resort, one can remove all slits and see if there is a signal. Wrong raster size or aspect ratio If the raster in the RTI has incorrect size and/or aspect ratio: Set raster size to 0, and then back to 25. This should restore the correct field of view. Go to Setup/Keyboard from the monitor window, and hit apply. This should restore the correct aspect ratio. 5

6 B. MECHANICAL PROCEDURES 1. Sample Loading and Unloading Procedures Loading into SAS chamber (airlock) all valves must be closed Make sure the nitrogen tank is open. Press the yellow vent button to vent the airlock Wait until there is a solid yellow light, then open the airlock Place the sample vehicle in the holder, and close the airlock Press the green pump button, wait until there is a solid green light Close nitrogen tank Loading Sample from SAS chamber into vessel chamber 1. Open SAS valve (EP9/airlock) and make sure sample is locked in position (little pin on top) 2. Move transfer rod into second position, check to see prongs are in the sample holder 3. Turn the knob on the transfer rod so the arrow is pointing towards the machine to lock the rod to the sample 4. Unlock the sample from the airlock holder (remove the pin on the top) 5. Make sure the carousel in the vessel chamber is in the right position (there is an empty holder to put the sample into), screw in the lock on the bottom of the wheel 6. Move the transfer rod to the third position 7. Turn the knob so the arrow is facing away from the machine to unlock the sample from the rod 8. Look to make sure the sample is in the carousel, then pull the rod back to the first position 9. Close EP9 valve Loading Sample from vessel chamber to analysis chamber 1. Move stage to unload position 2. Open vessel valve (EP13) 3. Rotate carousel to put desired sample in correct position, then lock in place with little pin from the top 4. Move the transfer rod into second position 5. Turn the knob so the arrow points towards the machine to lock the sample to the rod 6. Unlock sample from the vessel chamber (remove little pin from top) 7. Push the transfer rod to the third position, make sure it is on the stage 8. Turn the arrow away from the machine to unlock the sample from the rod 9. Pull the rod back to the first position 10. Close the EP13 (vessel) valve Unloading Sample from analysis chamber to vessel chamber 1. Move stage to unload position 6

7 2. Open vessel valve (EP13) 3. Rotate carousel so there is an empty spot in the correct position, then lock in place with little pin from the top to check position. Once you have the correct position, remove lock pin. 4. Move the transfer rod into third position 5. Turn the knob so the arrow points towards the machine to lock the sample to the rod 6. Pull the transfer rod to the third position, make sure it is in the carousel 7. Turn the arrow away from the machine to unlock the sample from the rod 8. Pull the rod back to the first position 9. Close the EP13 (vessel) valve Unloading Sample from vessel chamber into SAS chamber 1. Open SAS valve (EP9/airlock) and make sure sample is locked in position (little pin on top) 2. Make sure the carousel in the vessel chamber is in the right position (the sample is at the bottom even with the transfer rod), screw in the lock on the bottom of the wheel 3. Move transfer rod into third position, check to see that prongs are in the sample holder 4. Turn the knob on the transfer rod so the arrow is pointing towards the machine to lock the rod to the sample 5. As the rod is pulled back. look to make sure the sample comes out of the carousel as the rod is pulled back to the second position 6. Lock the sample in the SAS chamber by pushing in the little pin on top 7. Turn the knob on the transfer so the arrow is pointing away from the machine to release the sample, then pull the transfer rod back to the first position 8. Close EP9 valve Unloading out of SAS chamber (airlock) all valves must be closed 1. Make sure the nitrogen tank is open. Press the yellow vent button on the controls under the airlock and vessel chambers to vent the airlock 2. Wait until there is a solid yellow light, then open the airlock 3. Remove the sample vehicle from the holder, and close the airlock 4. Press the green pump button, wait until there is a solid green light 5. Close nitrogen tank 7

8 2. SIMS CCD OFFSET 1) Choose a position in CCD with a distinguishing feature, (edge, cross on silicon, etc) center it and record X-Y coordinates 2) Go to SIMS mode from this position and obtain image. Locate features that match those found in CCD mode. Center the image to match the CCD image. Record X-Y coordinates 3) Go back to CCD mode and find the implantation track to make sure your image was taken from the correct location. To calculate the offset, use the following equations: (XSIMS XCCD) = ^X (YSIMS XCCD) = ^Y ^X = delta X ^Y= delta Y OFFSET X = [(old X offset*) ^X] OFFSET Y = [(old Y offset*) ^Y] *-old offset values found in Setup window under the holder tab 8

9 C. CLEANING PROCEDURES 1. General For Parts under vacuum, tools used on those parts, and sample holders which will here in be referred to as "parts". 1) If the parts are visibly dirty the use of soap and water will usually be necessary. Take care not to abrade these parts, use either a light green scrub pad or a tooth brush. Rinse off the soap. Rinse again with 75% ethanol. *Note: the presence of water on any of the parts is of concern due to the nature of high vacuum. Therefore with the completion of this step it is imperative that no water comes in contact with the parts, otherwise process will need to start again. 2) Place the parts into a clean beaker. Rinse with acetone and then fill beaker so that the parts are covered with acetone. Sonicate the parts for 5 minutes pour out the acetone and rinse with acetone. Refill the beaker, sonicate and rinse four more times as described. *Note: at this point all parts should be handled with white gloves or tools cleaned previously cleaned to this level. 3) After the last rinse, rinse with 200 proof ethanol. Then cover the part in 200 proof ethanol in the beaker and sonicate for 5 minutes. Rinse and sonicate twice more. 4) Rinse with 200 proof ethanol one last time. Remove the parts and place them in a tray with a clean piece of aluminum foil. 5) Using the heat gun dry the parts for minutes. Then allow to cool but cover with either aluminum foil or a clean beaker to prevent condensation. *Note: care should be taken in the heating of electrical systems, double check for any precautions that should be taken before heating. Possibly it would be best not even to use the heat gun and find other means. 6) Parts are now ready for use in the high vacuum system, however maintain white glove treatment of parts. 9

10 2. Cleaning Source Unit Cleaning Ceramics for filament connection 6. Solution of equal parts of HCL, H2O2, and H2O 7. Sonicate in solution for 30 minutes or until clean 8. Drain solution and transfer to a petri dish 9. Heat in oven (preferably a vacuum oven) for at least 3 hours at 120 C 10. Ceramic parts are now ready for use in the high vacuum system, however maintain white glove treatment of parts Cleaning of Metal Parts 1. Recommend starting with soap and water, or with metal polish. Take care not to abrade these parts, use either a light green scrub pad or a toothbrush. Rinse off the soap or polish. Rinse again with 75% ethanol. Note: the presence of water on any of the parts is of concern due to the nature of high vacuum. Therefore with the completion of this step it is imperative that no water comes in contact with the parts, otherwise process will need to start again. 2. If this does not work well enough use procedure for Intense Cleaning of Metal Parts, otherwise continue to follow this procedure 3. Place the parts into a clean beaker. Rinse with acetone and then fill beaker so that the parts are covered with acetone. Sonicate the parts for 5 minutes pour out the acetone and rinse with acetone. Refill the beaker, sonicate and rinse four more times as described. Note: at this point all parts should be handled with white gloves or tools cleaned previously cleaned to this level. 4. After the last rinse, rinse with 200 proof ethanol. Then cover the part in 200 proof ethanol in the beaker and sonicate for 5 minutes. Rinse and sonicate twice more 5. Rinse with 200 proof ethanol one last time. Remove the parts and place them in a tray with a clean piece of aluminum foil 6. Using the heat gun dry the parts for minutes. Then allow it to cool, but cover with either aluminum foil or a clean beaker to prevent condensation. If the time is available use of the vacuum oven is preferred, 120 C. Note: care should be taken in the heating of electrical systems, double check for any precautions that should be taken before heating. Possibly it would be best not even to use the heat gun and find other means. 7. Parts are now ready for use in the high vacuum system; however maintain white glove treatment of parts Intense Cleaning of Metal Parts Solution of equal parts of NH4OH, H2O2, and H2O Sonicate in solution for 30 minutes or until clean Drain solution and transfer to a petri dish Heat in oven (preferably a vacuum oven) for at least 3 hours at 120 C Note: All vacuum ovens should be using non-oil pumps. Therefore don not use the lab vacuum lines. 10

11 5. Parts are now ready for use in the high vacuum system, however maintain white glove treatment of parts Cleaning of HT Ceramics 1. Remove all other source parts from the HT ceramics (or base ) of the source 2. Sand blast the ceramics to a smoke color, this is there natural color. (Handled by James Hill) 3. Goto step 3 of the Cleaning of Metal Parts. During the cleaning do not allow the area that is never under vacuum get wet (this is where the wires for the HT and Filaments come in and connect to the ceramics). This will usually involve holding the unit up side down the solutions. Note: care should be taken in the heating of electrical systems, double check for any precautions that should be taken before heating. Possibly it would be best not even to use the heat gun and find other means. 11

12 D. SOFTWARE PROCEDURES 1. Procedure for loading NanoSIMS 50 software (type only what is in quotes, not the quotes themselves) If Sun system is not on, turn it on Login: ims password: WAMo2art Once Sun system is up, open the server window*. after the /export/home/ims> string appears, type load68 after the >, hit return wait for the system to load up and the scan screen to appear. * if server is already running, hit ctrl+c, and follow from top Then, open the keyboard window and the file export/home/ims/notes: hit escape to get RT> prompt. copy and paste cm, hit return after the RC> prompt, copy and paste fill.b ec fd. hit return after RC> prompt, copy and paste move hit return after RC> prompt, copy and paste go 100c. hit return Go back to the server window: at the end of the /export/home/ims> string, type serveur_sun M68030 or!s (last command starting with S). Next, right click on the screen and select board. This will bring up the tool board on the side of the screen. click on setup, and hit apply after that, open up all the other tools to make sure they are loaded from preset (side tool bar) click load and load the parameter file you want, then click on the long button to send the parameters to the keyboard 12

13 2. Software - trolleys and preset Setting Trolley Radii 1. Adjust either position of trolley or B field to max counts on a trolley 2. Go to mass table, make sure B field on tuning screen matches the one in the mass table. Click on element you want and trolley you are working on, hit adjust 3. Go to the next trolley, start around radius of previous trolley, do same as before To create new preset 1. From preset window, go to new. Type name of new button 2. Click small square so that button setup appears. Choose a button, to add parameters you want, hit calib. 3. Change name of new button Implantation 1. Work with no diaphragm (D10) 2. Go to RTI, start scan then turn beam on, wait until there is a decent signal 3. Adjust C4y (from Q) to move the beam off the counters so as not to burn them Use of the Preset L1=7000V Toggle Switch for High Spatial Resolution Analysis To obtain the highest spatial resolution analysis (or smallest Cs Beam diameter), the voltage on lens L1 needs to be brought from the normal operating value of 0 volts up to a value of 7000 V. It is not advisable to simply use the thumbwheel to ramp up the L1 voltage as the Cs beam current will go through a maximum around 3000V. Even a brief exposure to this high Cs current can damage a sample, in particular if it is an ultrathin/em section. The toggle switch will change the L1 voltage from 0 to 7000V. It will also change the values of Cox, C0y, C1x, C1y to the optimum values corresponding to L1=7000V. To use the toggle switch, click on the Preset button on the NanoSIMS toolbar on the right of the screen. When you open the preset menu, a window will open with six rectangular boxes (below). The top box will be titled Large Current. If you click on the rectangular box entitled G0_080103, it will change the L1 voltage to 7000V and also the Cox, C0y, C1x, C1y values. To switch back to the condition where L1 = 0V, simply click on the rectangular box again. 13

14 3. Re-establishing Communication: With Keyboard If the values on the screen of the keyboard disappear or a row of black boxes appears in their place, the communication between the M68030 and the keyboard has been lost. To get it back, attempt the following: 1) Restart keyboard from the keyboard window. Hit escape, then follow procedure in notes binder; RT>cm..etc. If that does not work, go to step2. 2) Reset M There is a red button on board. Press it to reset the M Then go through normal program loading procedures found in the notes binder. If that does not work, go to step 3. Figure 1 M68070 board Figure 2 Reset button on M

15 3) Turn off VME (Switch labeled VME in the back of the vacuum control stack), wait for ten seconds before turning it back on. Reset M68070, then go though normal program loading procedures. With NanoSIMS Toolbar If any button on the NanoSims toolbar becomes inactive or unresponsive (it turns brown but the square at the top left does not turn green, or the square turns green but the button does not turn brown, do the following: 1) Quit the entire NanoSims toolbar by right-clicking on the top and selecting quit. 2) Log out of the Sun system and then log back in. There is no need to load up the software again since that was not stopped. The NanoSims toolbar should load up automatically and all buttons should be functional. 3) If the button(s) are still inactive, follow steps 2 and 3 from With Keyboard section above 15

16 4. How to Retrieve Full Range of Motion in Stage Motors First open up the window, then follow the prompts below Y Direction (Horizontal) select motors 5 Select Menu moteurs 1 select 9 : enter the Y motor address and speed dl select 4 : move to inner stopper select a : ask for a move of steps (sample stage should be near center position) select 0 : exit the move motors menu select 7 : read stage position (should be around 20305, but not necessarily exactly) select f : save this position in the EEPROM X Direction (Vertical) select motors 5 Select Menu moteurs 1 select 9 : enter the X motor address and speed cl select 4 : move to inner stopper select a : ask for a move of steps (sample stage should be near center position) select 0 : exit the move motors menu select 7 : read stage position (should be around 53566, but not necessarily exactly) select f : save this position in the EEPROM After completing the above steps, exit motor controls by entering 0, then reset the board and reload the software. 16

17 5. Cutting the Current to Trolley Motors Use this procedure when turning off motor control chassis (top chassis). Doing this will protect IC circuits and allow user to Restore trolleys without having to initialize them. Make sure tuning window is closed, then open window on newims Select MENU MOTEUR (choice 1) by typing 1, then hit return 2a. If there are no menu choices displayed, type 0 (zero) and hit return. 2b. If a menu is displayed, but there is no MENU MOTEUR choice, select motors (choice 5) by typing 5 and hit return, then select MENU MOTEUR Type l (as in lake ) to go to English language menu Type 9 to change motor address, hit return Type in motor address and speed. For example, for Trolley 1, type 8l, then hit return (always use lowest speed choice, which is l as in lake). Type h to cut current running to the selected motor, then hit return Repeat steps 4-6 for all remaining motors. Addresses can be found on the side of each trolley motor and at the end of this procedure After the current is cut to all trolley motors, disconnect pin cable labeled P980 from trolley motors* Turn off motor control chassis* After necessary work is completed, turn on motor control chassis* Reconnect pin cable P980 * Open up tuning window, select Restore from the prompt Simply move each trolley any amount to return current flow to that particular trolley motor *It is essential that steps 8 11 be completed in that order, otherwise user will have to initialize trolleys after turning chassis back on Motor addresses: DETECTORS Trolley Trolley Trolley Trolley 4...b STAGE MOTORS Vertical Motor (X)...c Horizontal Motor (Y)...d 17

18 6. Nikon-to-MIMS Transformation You can launch the n2mc from a shell window on newims. Make sure you are in the /nrims/home/shared/sample_holders/<current sample holder folder> directory (ie /nrims/home/shared/sample_holders/sw6). It simply prints a '>' prompt. Type in the letter 'a' to append a tiepoint ( pair of Nikon,MIMS coordinates ) as follows; >a Enter Nikon X,Y> Enter MIM's X,Y> Point[1] Stage 15803,13312 Mims 9392, >a Enter Nikon X,Y> Enter MIM's X,Y> Point[2] Stage 37159,10027 Mims , >a Enter Nikon X,Y> Enter MIM's X,Y> Point[3] Stage 25514,41660 Mims -52,15555 >c cx(0,0) cx(0,1) cx(0,2) 0 cx(1,0) cx(2,0) 0 cy(0,0) cy(0,1) cy(0,2) 0 cy(1,0) cy(2,0) 0 >w Enter a filename to save the coefficients > Coeff.txt Coeff.txt cx(0,0) cx(0,1) cx(0,2) 0 cx(1,0) cx(2,0) 0 cy(0,0) cy(0,1)

19 cy(0,2) 0 cy(1,0) cy(2,0) 0 >q After entering three ( or more ) tiepoints with the 'a' command, you use 'c' to compute the coefficients for the offset and rotation, and the 'w' command to generate a 'coefficients' file to be saved to disk. Exit n2mc with the 'q' command. Next you use the n2m2 command as follows, n2m2 <stagefile> <CoefficientsFile> This takes a nikon stage file and writes the holder data with the translated and rotated co-ordinates. Finally clear all current points from the holder window, and hit the reload button to import the new coordinates. 19