Stepper 2 (AutoStep 200) Operating Procedures: Difference between revisions

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==Other Useful links for this system:==
{{WIP}}
== Cleaning the back-side of wafer ==
If the back side of wafer has some resist residue or particulates, this can cause errors in the interpreted best focus point since the wafer surface may be at a different height.
# Make sure all work surfaces/spin chucks/hot plates are cleaned! Don’t use wipes, instead use cleaned steel surfaces.
# Spin coat resist following the recipe for spinning/baking specific resist.
# Check back-side of wafer thoroughly for resist residue/particulates before loading into system!
# If you see particulates, try to blow off with high N2 flow first, you may need a razor blade to remove stubborn particles.
# If you see resist residue, do next:
## Place wafer upside down in POLOS spinner using non-contact chuck.
## Set spin speed to 2000rpm.
## Spin wafer, wait until at top speed.
## Squirt Acetone on sample back for 3 seconds. Followed by ISO for 3 sec.
## Spin Dry while blowing with N2.
# Load the wafer on chuck and then stage.


*[[Stepper 2 (Autostep 200) - Chuck Selection]] - Quick Summary
== Loading a wafer into the system ==
*[[Stepper 2 (Autostep 200) - Table of Chucks, Shims, Target Thicknesses]] - Detailed Info on the same
# Attach the appropriate chuck to the system. How to select proper chuck?
*[[Autostep 200 Mask Making Guidance|Stepper 2 (Autostep 200) - Mask Making Guidance]]
# Make sure you know your substrate thickness and wafer diameter.
# '''TARGET thickness''' '''is''' : '''12.150mm +/- 0.1mm (TARGET= Chuck thickness+ Substrate thickness)'''
# Each chuck has two numbers on top side (for example '''100mm/500um''') showing wafer diameter, and substrate thickness. ( i'''''nsert the link with TARGET thickness''''' )
# Place your wafer centered on the chuck, noting the orientation (major flat always touching '''two front screws''', minor flat touching the screw either on left or right side)
# If you are doing an alignment step, make sure to place the wafer in the same orientation as it was in the first exposure.
# The set screws in the chuck can help to get reproducible placement of the wafer.
# When the wafer is in place, flip the chuck vacuum switch upwards to hold the sample.
# Place the sample chuck onto the stage, again trying to be repeatable, and flip the stage vacuum switch upwards to hold the chuck.
# If your sample is thin (150um thinner than the number on top side of chuck), then you need to use '''SHIM ( we have 130,180, 230, 260um metal shims)'''
# If you need a shim with different thickness you can try cutting some shim stock (stored in drawer next to Autostep200).
# Be careful when placing the chuck on to the system. Do not set the chuck onto the built-in reticle on the left side of the stage.
# Make sure the chuck vacuum is properly holding the chuck in place (it can tip forwards before the vacuum holds it in place).
# At this stage type '''AWLT Jobname\Passname'''. This will test the auto-leveling of your wafer ( Autoleveleing cannot be done on pieces smaller then ¼ of 2”, so when writing the program make sure that you at the LEVELER batch size input value -1( TURN off leveling).
# At '''"START AWH"''' (automatic wafer handling) prompt, press '''MANUAL''' button.
# Press '''MANUAL''' again.
# Choose “N” in an answer to all questions.
# If you have an autofocus error or leveling error, the system will tell you


== Two Alignments: ==
== Reticle Loading and Unloading ==
'''Loading the reticle'''


=== <small>1) Wafer alignment to the system ''/'' <u>Global (Manual Operation Only</u>)</small> ===
 Mask Alignment on this system is automatic. You need to have the square marks on the top and bottom of the mask. These are put on automatically by Photronix and the gds file can be obtained from Brian Thibeault if you use a different vendor. There are 10 reticle box positions on the elevator. '''Slot 1''' is dedicated for a calibration mask. Slots 2-10 are available for your use. Slots will NOT be dedicated for any users.
The keyboard alone is used in this part of the exposure sequence to align the wafer to the system.  The sequence of operations you do will depend on whether or not you used standard alignment keys or not.  If you placed the sample close to the position you did during the first exposure, you should see an alignment mark in the right side of the screen.  If not, you will need to find this mark using the position joystick by following a spiraling outward from the initial position. Pressing “F” repeatedly on the keyboard will do this spiral finding for you automatically. The red arrows on the number keys indicate the direction of movement for each keystroke.  There are also + and -theta (angle) keys for rotation.   Inc and Dec are used for microscope focus.  The enter key on the numeric keypad changes from fast to slow movement.   To change the joystick speed hit O on the main keyboard.  Once the alignment mark is found follow one of the following procedures. Most of the time we use '''Non-Standard Alignment keys''':
# Load the reticle into a box with chrome side down (shown in the figure 1.)
# Type RMSL on the main computer at the colon prompt.
# Swing the reticle forks 90 degrees away from the reticle elevator.
# Pull out knob, insert box in one of the slots (2-10), release knob to hold   box.
# Make sure the box is sitting properly in place.
# Hit Enter on the computer and the system will map the reticles.
# On them main monitor you will get information about the reticle name and the slot# it is loaded (if the reticle does not have a name it will say just NONE)
'''Unloading the reticle'''


'''Standard Alignment Keys:'''
 At the end of each job you need to unload the mask

# Type RMSR on the main computer at the colon prompt.
#Adjust the focus (Inc and Dec keys) to get a crisp image (you might have to change speed with the Fast/Slow key).
# Wait for the reticle to be loaded back in the reticle box.
#Align the right mark using the numeric keys labeled with arrows.
# Type RMSL on the main computer at the colon prompt.
#Use the Theta keys to rotate the left image into position. Positive Theta = clockwise rotation of chuck.  If you run out of theta alignment, you will need to adjust your sample on the chuck.
# Get your reticle from  the reticle box
#The left image(left side of monitor) is used for theta only. The right image(right side of monitor) is used for x, and y alignment. Use the right image (right side of monitor) to do your best alignment. This step is important.
# '''NOTE:''' '''NEVER''' try to manually unload the reticle (as you would in GCA 6300 Stepper #1). Always use commands.
#Repeat process until satisfied with the alignment. You can obtain better than 0.2 um alignment consistently if you are careful.

'''Non-Standard Alignment Keys:'''

#Adjust the focus (Inc and Dec keys) to get a crisp image (you might have to change speed).
#Align the right mark using the numeric keys labeled with arrows.
#Press "A" on the main keyboard to toggle to the left alignment mark.
#Use the Theta keys to rotate the left image into position. [Positive Theta= CW, Negative Theta=CCW rotation of chuck]
#If you run out of theta alignment, you will need to adjust your sample on the chuck.
#The left image(left side of monitor) is used for theta only. The right image(right side of monitor) is used for x, and y alignment. Use the right image (right side of monitor) to do your best alignment. This step is important.
#Press "A" again to move to the right alignment mark
#Again adjust the right alignment mark
#Repeat process until satisfied with the alignment.
#Once alignment is finished, you have two option for pieces (quarters): BR orientation, and BL orientation.
#'''BR orientation''' - make sure you are on the right alignment mark before pressing "EXP", '''BL orientation''' - make sure you are on the left alignment mark before pressing "EXP". In both cases do your best alignment, but verify final alignment looking at the right image (right side of monitor).
#After global alignment, press EXP on small keyboard and the job will be executed.
#Remove the sample from the stage when done.
#Develop resist and inspect in microscope for alignment.
#Computer may ask for next wafer.  To escape out of this press CTRL C followed by A and the enter key to abort out of the loop. If you have another wafer with the same job\pass, you can do it now without aborting.

=== <small>2) '''Wafer Alignment to mask ''/'' <u>Local Alignment (DFAS)</u>''' :</small> ===
The best way to use this is to use a mapping routine followed by a shoot using the corrections given by the map.  A mapping routine should be set-up in your mapping pass. Usually we do not map all dies, just selected ones. You could selected in each row few dies. The mapping pass should have a name different then any other pass. It could be named '''mapxx''' or some other name (for example: '''local'''). Make sure you specify '''die x die''' is to be used and that you have the correct key offsets for the global and local alignment marks.  The command you will use is:

* '''MAP jobname\mapxx, passname'''

#Proceed as normal. Find a global alignment mark and do your best alignment. The first pass (mapxx) is the mapping pass. The system will do mapping, using dies that are selected in mapping pass. It will look for DFAS alignment mark in each die, and make corrections. When asked to make corrections, say yes. After corrections are applied, the exposure job will be performed shooting the pass named " passname". Follow instructions on screen when using this function.
#Remove the sample from the stage when done. (If Match was enabled, you will have to wait until the match is done again.  It will do this before asking you for the next wafer). Develop resist and inspect in microscope for alignment (if needed)
#Computer will ask for next wafer.  To escape out of this press CTRL C followed by A and the enter key to abort out of the loop.  If you have another wafer with the same job\pass, you can do it now without aborting by placing it on the chuck and hitting MANUAL.

Latest revision as of 23:24, 8 January 2024

Other Useful links for this system:

Two Alignments:

1) Wafer alignment to the system / Global (Manual Operation Only)

The keyboard alone is used in this part of the exposure sequence to align the wafer to the system.  The sequence of operations you do will depend on whether or not you used standard alignment keys or not.  If you placed the sample close to the position you did during the first exposure, you should see an alignment mark in the right side of the screen.  If not, you will need to find this mark using the position joystick by following a spiraling outward from the initial position. Pressing “F” repeatedly on the keyboard will do this spiral finding for you automatically. The red arrows on the number keys indicate the direction of movement for each keystroke.  There are also + and -theta (angle) keys for rotation.   Inc and Dec are used for microscope focus.  The enter key on the numeric keypad changes from fast to slow movement.   To change the joystick speed hit O on the main keyboard.  Once the alignment mark is found follow one of the following procedures. Most of the time we use Non-Standard Alignment keys:

Standard Alignment Keys:

  1. Adjust the focus (Inc and Dec keys) to get a crisp image (you might have to change speed with the Fast/Slow key).
  2. Align the right mark using the numeric keys labeled with arrows.
  3. Use the Theta keys to rotate the left image into position. Positive Theta = clockwise rotation of chuck.  If you run out of theta alignment, you will need to adjust your sample on the chuck.
  4. The left image(left side of monitor) is used for theta only. The right image(right side of monitor) is used for x, and y alignment. Use the right image (right side of monitor) to do your best alignment. This step is important.
  5. Repeat process until satisfied with the alignment. You can obtain better than 0.2 um alignment consistently if you are careful.

Non-Standard Alignment Keys:

  1. Adjust the focus (Inc and Dec keys) to get a crisp image (you might have to change speed).
  2. Align the right mark using the numeric keys labeled with arrows.
  3. Press "A" on the main keyboard to toggle to the left alignment mark.
  4. Use the Theta keys to rotate the left image into position. [Positive Theta= CW, Negative Theta=CCW rotation of chuck]
  5. If you run out of theta alignment, you will need to adjust your sample on the chuck.
  6. The left image(left side of monitor) is used for theta only. The right image(right side of monitor) is used for x, and y alignment. Use the right image (right side of monitor) to do your best alignment. This step is important.
  7. Press "A" again to move to the right alignment mark
  8. Again adjust the right alignment mark
  9. Repeat process until satisfied with the alignment.
  10. Once alignment is finished, you have two option for pieces (quarters): BR orientation, and BL orientation.
  11. BR orientation - make sure you are on the right alignment mark before pressing "EXP", BL orientation - make sure you are on the left alignment mark before pressing "EXP". In both cases do your best alignment, but verify final alignment looking at the right image (right side of monitor).
  12. After global alignment, press EXP on small keyboard and the job will be executed.
  13. Remove the sample from the stage when done.
  14. Develop resist and inspect in microscope for alignment.
  15. Computer may ask for next wafer.  To escape out of this press CTRL C followed by A and the enter key to abort out of the loop. If you have another wafer with the same job\pass, you can do it now without aborting.

2) Wafer Alignment to mask / Local Alignment (DFAS) :

The best way to use this is to use a mapping routine followed by a shoot using the corrections given by the map.  A mapping routine should be set-up in your mapping pass. Usually we do not map all dies, just selected ones. You could selected in each row few dies. The mapping pass should have a name different then any other pass. It could be named mapxx or some other name (for example: local). Make sure you specify die x die is to be used and that you have the correct key offsets for the global and local alignment marks.  The command you will use is:

  • MAP jobname\mapxx, passname
  1. Proceed as normal. Find a global alignment mark and do your best alignment. The first pass (mapxx) is the mapping pass. The system will do mapping, using dies that are selected in mapping pass. It will look for DFAS alignment mark in each die, and make corrections. When asked to make corrections, say yes. After corrections are applied, the exposure job will be performed shooting the pass named " passname". Follow instructions on screen when using this function.
  2. Remove the sample from the stage when done. (If Match was enabled, you will have to wait until the match is done again.  It will do this before asking you for the next wafer). Develop resist and inspect in microscope for alignment (if needed)
  3. Computer will ask for next wafer.  To escape out of this press CTRL C followed by A and the enter key to abort out of the loop.  If you have another wafer with the same job\pass, you can do it now without aborting by placing it on the chuck and hitting MANUAL.
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