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

From UCSB Nanofab Wiki
Jump to navigation Jump to search
(→‎Reticle Loading/Unloading: Work In Progress)
Line 15: Line 15:


== Reticle Loading and Unloading ==
== Reticle Loading and Unloading ==
⚫
'''Loading the reticle'''
The alignment of the reticle (mask) to the system is critical for achieving reproducible alignment.  System alignment marks on the reticle are located near the right and left edges of the mask and are 103 mm apart so they do not get exposed within the 100 mm exposure area of the mask.  These marks are put on automatically by Photronix and the gds file can be obtained from Brian Thibeault if you use a different vendor. Use the following procedure to align the mask correctly to the system.


 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.
⚫
'''Loading the reticle:'''
# 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'''


 At the end of each job you need to unload the mask
1)   Unlock spindle and swing lamp column to middle position so that the lens is exposed.
# Type RMSR on the main computer at the colon prompt.

# Wait for the reticle to be loaded back in the reticle box.
2)   Place mask chrome side down so that wording appears correct ( as seen in L-edit file).
# Type RMSL on the main computer at the colon prompt.

# Get your reticle from  the reticle box
3)   Swing lamp column so that objective can be used to align mask, DO NOT tighten spindle lock at this time.
# '''NOTE:''' '''NEVER''' try to manually unload the reticle (as you would in GCA 6300 Stepper #1). Always use commands.

4)   Using your hands and looking through microscope, shift and rotate mask so that the “crosses” are roughly aligned

5)   Tighten spindle lock. This releases a vacuum holder onto the top of the mask so that the mask may be precisely aligned.

6)    Looking through microscope, use alignment knobs (x,y) to translate and rotate(Θ) the mask into position.  First focus the objective by using the knob on top of the microscope.  Use the right alignment mark for the x-axis alignment and both alignment marks for the y-axis and rotation alignments.  '''NOTE:''' To get best and fastest results approach alignment from one direction, do not try to wiggle back and forth about the alignment position. Backlash in the mechanics can make this frustrating. You should see equal amounts of light in between all lines when the mask is aligned well (within 0.1 um).

7)   Once mask is aligned, pull the reticle vacuum button to the left of the lens column. The reticle is now vacuumed to the system.

8)   Use the stencil (usually L-shape mask cover), to cover part of the mask plate that you do NOT want to be exposed. If you have just one layer on your mask plate, you do not need to use the stencil. There are also blade apertures that could be used. The knobs on the lamp column  (X,Y) can be adjusted to 100,75,50 and 25% to be open. Fully open blade apertures would be at 100%

9)   You are now ready to proceed with a focus job, map job, or exposure job.

10) '''This part is important:''' If alignments are critical, do not just brush through this procedure.  The global alignment requires good, precise alignment of the reticle with the system in order to work correctly.  The local alignment system can adjust for local X and Y misalignment, but not rotational errors.

⚫
'''Unloading the reticle:'''

1)   Unlock spindle and swing lamp column to middle position so that the lens is exposed.

2)   Once mask is aligned, pull the reticle vacuum button to the left of the lens column. The reticle is now vacuumed to the system

Revision as of 20:42, 31 May 2019

UnderConstruction.jpg

Work In Progress

This article is still under construction. It may contain factual errors. Content is subject to change.


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.

  1. Make sure all work surfaces/spin chucks/hot plates are cleaned! Don’t use wipes, instead use cleaned steel surfaces.
  2. Spin coat resist following the recipe for spinning/baking specific resist.
  3. Check back-side of wafer thoroughly for resist residue/particulates before loading into system!
  4. If you see particulates, try to blow off with high N2 flow first, you may need a razor blade to remove stubborn particles.
  5. If you see resist residue, do next:
    1. Place wafer upside down in POLOS spinner using non-contact chuck.
    2. Set spin speed to 2000rpm.
    3. Spin wafer, wait until at top speed.
    4. Squirt Acetone on sample back for 3 seconds. Followed by ISO for 3 sec.
    5. Spin Dry while blowing with N2.
  6. Load the wafer on chuck and then stage.

Reticle Loading and Unloading

Loading the reticle

 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.

  1. Load the reticle into a box with chrome side down (shown in the figure 1.)
  2. Type RMSL on the main computer at the colon prompt.
  3. Swing the reticle forks 90 degrees away from the reticle elevator.
  4. Pull out knob, insert box in one of the slots (2-10), release knob to hold   box.
  5. Make sure the box is sitting properly in place.
  6. Hit Enter on the computer and the system will map the reticles.
  7. 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

 At the end of each job you need to unload the mask

  1. Type RMSR on the main computer at the colon prompt.
  2. Wait for the reticle to be loaded back in the reticle box.
  3. Type RMSL on the main computer at the colon prompt.
  4. Get your reticle from  the reticle box
  5. NOTE: NEVER try to manually unload the reticle (as you would in GCA 6300 Stepper #1). Always use commands.
Retrieved from "https://wiki.nanofab.ucsb.edu/w/index.php?title=Stepper_2_(AutoStep_200)_Operating_Procedures&oldid=156412"