Quanta FIB Basic Training Eucentric Pt Deposition and

Quanta FIB Basic Training Eucentric, Pt Deposition, and Trenching Central Analytical Facility The University of Alabama

Loading Samples • • In order to load samples the chamber must first be vented to atmosphere From the Beam Control page, press the vent button The system will automatically spin down pumps and begin to purge the chamber with nitrogen Allow a few minutes for the vent cycle. Do not pull on the door • • As the chamber is vented, the chamber pressure will rise The icon representing the FIB will begin to change color (orange) as the column and electron column come to atmosphere Atmosphere e- column Ion Column Chamber High Vacuum

Loading Samples • • With the chamber at atmosphere, pull on the handle on the front of the chamber to open The stage consists of two parts: • • 1 - A base that can be loosened (counter clockwise rotation) and tightened (clockwise rotation). Loosening this base will enable the center portion of the stage to be lowered or raised. 2 - The center portion of the stage where the sample is secured. Counter clockwise rotation will raise this, clockwise rotation will lower it. When securing samples, use the provided Allen key to tighten the set screw until it is in contact with the sample. Do not over tighten. With a sample mounted on a SEM stub or similar holder, secure the holder in the stage and tighten the set screw Turn the base of the stage clockwise until snug. Do not over tighten • Leaving the base loose will produce horizontal translation when finding eucentric 2 1

Loading Sampes • • In order to ensure samples do not collide with the objective lens upon loading, a tool known as “the elephant is used Below the “trunk” is a 15 mm mark, which corresponds to rough eucentric height inside the chamber With sample mounted on the stage, bring the elephant in to place over the sample and ensure it is beneath the trunk If it is too tall, loosen the base of the state and turn the central portion clockwise to lower the stage. Secure the base with a clockwise rotation and check again

Chamber Evacuation • • • With a sample secured in the stage and below the 15 mm mark, close the chamber door Ensure the O-ring of the chamber door is flush with the chamber From the Beam Control page press pump – a light push against the chamber door while doing this will ensure a good seal • • The system will begin to pull a vacuum on the chamber and chamber pressure will begin to lower Operation can begin once the chamber is in the mid to low 10 -5 Torr range and the FIN icon is completely green

Eucentric Position The eucentric position is the position where a feature does not move from the field of view during tilt. It is also the coincidence point where both beams intersect

Finding Eucentric • • • Begin by zeroing out the beam shift on the SEM and FIB channels. Rough mechanical alignments will be followed by using beam shift to fine tune the position of the ROI. Locate a distinct feature on the surface of your material and focus on it. Double click to center that feature in the SEM quad. If the center cross is not present, use Window Center Cross to bring it up. Make sure the chamber scope is live during the following steps, as with any movement of the stage A working distance of 15. 3 is the rough eucentric position of the SEM. Either: • 1) Set the WD to 15. 3 mm and raise the stage until your feature comes in to focus. After this link Z to FWD, or • 2) Focus on the feature. Once focused, WD should be > 15. 3 mm. Link Z to FWD to update the Z value in the Navigation page. From here, type in 15. 3 in the Z field to raise the stage • Pressing ESC will stop all stage movement From the Navigation page tilt to 10º and watch the feature on the SEM window. If there is translation up or down, adjust the stage using the Z knob on the FIB door. If there is horizontal translation the sample or stage may not have been secured properly • NOTE: When tilted, only use the Z knob to make these adjustments in the SEM quad. Do not double click From the Navigation page tilt to 52º and repeat the previous step. Tilt back to 0º and observe the feature. If it remains centered you have found the eucentric position. Fine tune focus and link Z to FWD to set this height in the software. For finding the coincidence point turn on the ion beam and use the beam shift knobs to center the feature in the FIB quad A WD of 15. 3 -15. 4 is ideal for preventing collision between sample and Omniprobe or GIS.

Platinum Deposition • Prior to platinum deposition, the source will need to be heated • • • Find a recognizable feature or region for lift out (blue hexagon in this case) Find eucentric/coincidence at 52º and check that WD is large enough that there will be no collision • • From the patterning menu under GIS, right click “Heat” and select “Heater” The progress bar will fill as heating begins Link Z to FWD must be checked for this option to be enabled For samples that are not perfectly flat the user must be aware of where the GIS/Omniprobe insert and possible collisions Set ion beam current to a low value to begin with (10 -30 p. A) for imaging purposes. A higher current (0. 1 -0. 3 n. A) will be used for depositing a pad

Creating a Pt Bar • Under the Patterning page, check the box by GIS to insert the GIS • • The GIS should be inserted before, and removed after, the Omniprobe has been inserted/retracted to prevent vibration and sample loss Switch ion beam current to 0. 1 -0. 3 n. A, using Fine View (F 7) to focus/stigmate away from the ROI On the patterning page, select a shape (often rectangle). Left click and drag to create a rectangle 16 µm x 1. 5 µm x 0. 8 µm Ensure the Application is set to Pt Dep and not Si Observe the predicted deposition time – 3 -5 minutes is common Press the Start Patterning button at the top of the x. T software to begin patterning. Periodically pause patterning and image on the SEM quad, watching for any drift. If imaging on the FIB quad use a single integration to prevent damage to the sample When complete the flow from the GIS will close Retract the GIS Ion Beam View Cross Section

Initial Cuts • • • Remaining at 52º, select “Regular Cross Section” from the patterning drop down Based on the material, ion beam current may be between 0. 3 n. A to 7 n. A Use the Fine View (F 7) tool to focus and stigmate at this higher current away from the ROI Left click and drag to draw a rectangle below the Pt bar (see Ion Beam View, rectangle 1) Because these cuts are at elevated beam currents, the area cut will be slightly larger than the pattern drawn. To account for this some room is left between the pattern and the Pt bar to minimize damage Dimensions can be typed in manually under the Basic tab on the Patterning page • Length should be longer than Pt bar, 4 -5 µm depth for Z axis is Ion Beam View Cross Section 1 1 2 2 1 common A number 1 will be visible upon drawing the pattern. This indicates the direction of ion beam scan and the deeper side of the cut (see illustration) Begin patterning, periodically pausing to view cutting progress and ensure there has been no drift Once cutting for box 1 is complete, the pattern can be rotated 180º from the Basic tab of the patterning menu and cutting repeated for the other side • Note – this can only be done at 52º, normal to the ion beam. At lower angles the stage must be physically rotated. 1 Regular Cross Section pattern, with the number 1 representing the direction of beam scan and the deeper edge of the cut

Fine Cuts • • • With initial trenches cut, lower current clean up cuts will be made adjacent to the Pt bar Drop beam current to the 0. 3 -1 n. A range, utilize Fine View (F 7) to adjust focus and stigmation away from the ROI From the patterning dropdown, select either Rectangle or Cleaning Cross Section Similar to previous steps, left click and drag to draw the pattern adjacent to the Pt bar This pattern can also be rotated from the Basic tab on the patterning menu to cut on the opposite side of the bar Ion Beam View Cross Section 2 1

Undercutting • • With initial and fine cuts made it is time to begin undercutting what will be the wedge from our sample Ensuring the GIS is retracted, tilt the stage to either 22º or 34º. The different angles will result in a different wedge geometry based on user preference Adjust focus and stigmation for a current in the 1 -3 n. A range Using the Rectangle pattern, draw a narrow box within the first trench cut (see illustration) Begin patterning, periodically pausing to check progress and ensure no drift Once the first cut finishes, perform a relative rotation of the stage 180º (ensuring compucentric rotation is checked) At the same tilt angle, repeat the cutting process to create the wedge shape Note that it is possible to see ion beam damage in the trench opposite of the cut – this is a good indication the sample has been properly undercut and should be actively looked for

Cantilever Cut • • • With the wedge undercut, one final cut is needed before the lift out process can begin Return to 52º with a beam current of 1 -3 n. A, adjusting focus and stigmation as needed Using a Rectangle pattern, draw a narrow pattern normal to the trenches already cut. A z value of 4 -5 microns, similar to trenches, is fine • • • Because the ion beam image and the e- beam are scan rotated 180º from each other, the cut has been placed on the left side of the wedge as that is the side from which the Omniprobe will insert in the ion beam field of view Begin patterning, pausing periodically to check for drift and observe progress The cut is made slightly away from the Pt bar to minimize beam damage to the protected region When complete, rotate 90º and observe the edge geometry If wedge geometry is satisfactory and properly undercut, the sample is ready for In situ Omniprobe lift out Ion Beam View