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Electonic Visions 620 Aligner, evalign

The Electronic Visions system is comprised of the precision optical 620 Aligner and the 501 Wafer Bonder. With the standard mask frame insert, the 620 Aligner module can perform precision mask-to-wafer front- or back-side alignment for near-UV photoresist exposure in any one of four modes (proximity, hard- and soft- contact, and vacuum contact.) With a specially provided bond tool, the 620 Aligner can perform proximity alignment of two wafers for processing in the 501 Bonder. Our current configuration accommodates 4" or 6" wafers and 5" or 7" masks.

Picture and Location

 EV Aligner

This tool is located at D23 on the Lab Map.


Process Capabilities

Cleanliness Standard

The evalign appears in all three equipment groups (clean, semiclean, and gold) as part of the litho & analytical tools set.

Performance of the Tool

What the Tool CAN do

  • Interchangeable mask frame and bond tools permit alignment of mask-to-wafer or wafer-to-wafer.
    • Frontside mask-to-wafer alignment accuracy to < 1 microns.
    • Precision front-to-backside alignment to <  2 micron.
    • Four different mask exposure modes: proximity, soft- and hard- contact, and vacuum contact.
    • Fully motorized, split field microscopes with multiple objectives for wafer top and bottom side viewing.
    • Backside alignment modes: optical image capture, user-specified cross-hairs, or customized alignment keys.
    • Near UV (350 - 450 nm) lamp source.

    (Please note that there is a two-hour reservation limit on this tool during prime time.)


Special Notes or Restrictions

  • There is a two-hour limit on reservation length on this tool during prime time
  • Clean front and back of mask before use
  • Clean mask every one to five wafers for thicker resists and as needed for other resists.


How to Become a User

  1. "All Litho" is required before training on any of the lithography tools. Contact the trainers for the class schedule and training materials (which must be reviewed before the class).
  2. Read all material on the SNF website concerning this tool, including Background, Process Capabilities, Operating Procedures and Process Monitoring.
  3. Contact SNF training contact on the Equipment Summary page.

Operating Procedures for Frontside Alignment

Function Overview: Optical lithography contact/proximity aligner-bonder

  • 5 exposure modes: vacuum contact, vacuum hard, hard contact, soft contact, and proximity
  • frontside and backside alignment
  • objectives available: 5X, 10X, 20X, and flat objective (for pieces)
  • bonding chucks for anodic bonding, thermal compression bonding and fusion bonding.
  • 2" chuck can be used for 2" wafers and pieces as well
  • minimum resolution in dark field = 1.0 µm line and <1 µm contacts
  • minimum resolution in clear field = 2 µm line and 2 µm contacts
  • 4" wafers, 5" masks
  • 6" wafers, 7" masks
  • lamp calibrated: CI1 at 15 mW/cm2 @ 365 nm
  • max wafer thickness 4.6 mm



  • Enable "evalign"
  • Do not touch the power supply, it is always on!
  • PC Power is left on
  • Do not lean on the system while working.
  • You need to make sure that the chuck is centered as much as possible to the mask holder. You can start by putting the micrometers x, y, and theta to the mark we have made on the micrometers.
  • Click icon ev620
  • OR if already there click on login and enter "620" for name and enter "620" for password
  • Initialization begins.
  • If necessary change chucks (this should not be necessary, but check that the appropriate chuck and mask holder are in place).
    • Change from Bonding Chuck to Wafer Align Chuck
      • Use Clean gloves!
      • Remove vacuum line
      • Remove bonding chuck and replace with align chuck (octagonal shaped vacuum pattern on bonding chuck). Lift chuck out of frame from below.
      • Replace vacuum line
    • Change from Bond Tool Frame to Mask Holder
      • Use Clean gloves!
      • Bond Tool - use clean gloves, do not touch chuck part.
      • Remove Bond tool -
        • Hold by feet and lift out.
      • Lift bond tool frame out.
      • Lower mask holder in
  • Follow instructions on screen (arrow indicates a machine instruction)
  • ->Move <tray out>
  • Double click on the process you want. These processes are standard processes; only change exposure time, alignment gap (40 µm is recommended for standard wafers; adjust the alignment gap based on your wafer and resist thickness) and other necessary changes. Do not save the changes!
    • Standard programs are: Top side align; bottom align; Si-Gl bond; Si-Si bond.


Process=Top side Align Mask Holder=5" Wafer=4"
Mask holder= 7" wafer=6
Process Mode=transparency Side=top (bottom)
Exposure mode=continual (interval) Exposure time=
Contact Mode=soft, hard, vac, vac/hard Delay time=
Proximity gap µm=0 Interval=
Separation µm=40 (gap during alignment)  
    For Contact Alignment select one :
    • Selecting V-Cont (space between wafer and mask is evacuated)
    • Selecting H-Cont
      • Adjust chamber pressure with H-Cont
      • Adjust the desired N2 pressure on the regulator. (too high a pressure could result in vibration of the wafer- this could be eliminated by using both V-Cont and H-Cont --see below.
    • Selecting V-Cont and H-Cont
      • You can select both (only with an adjusted nitrogen pressure of 0). Not recommended.
      • Adjust chamber vacuum with hard cont. and press <CONTINUE>
  • Click "Run" (see reference manual for screen view 18-50)
  • ->Save changes? NO (use them for your process only, do not change the program permanently)

Load Mask

  • ->Insert Mask Holder (this should already be in place)
  • press <CONTINUE>
  • ->Insert Mask with load frame and press <continue> (mask frame loaded with tab on right).
    • Load chrome side down and the wafer flat side to the right
    • (Note: If you are going to do backside alignment there is a limited area to view the targets, plan accordingly when you make masks for this machine).
  • ->Please Wait
  • ->Move tray in
  • ->Please Wait (long wait)
  • ->Adjust Mask
    • To adjust targets of the mask, you use split field microscope.
    • Press "Scan Optic" in the "Position-Menu" and you can move the microscopes with the joystick in x y and z direction (small motions give slower responses). For x and y push forward back or right or left, for focus rotate clockwise or counter clockwise.
    • To adjust for rotation use the micrometer screw ( since the mask is not yet attached by vacuum)
    • When targets have been found and focused press "CONTINUE". (to attach mask with vacuum)
  • ->Please Wait
  • ->Move <TRAY OUT>
  • ->Remove loadframe and press <CONTINUE>
  • ->Insert substrate and press <CONTINUE>(to activate vacuum) (OR press EXIT to unload mask)
    • Load wafer
    • During separation is a good time to change menu selections (ie time and separation). Select "Recipe",make changes and click on "move to" .
    • Warning if you chose "Exit", you must unload mask (when asked "Do you want to unload mask" - answer yes).
  • Check vacuum.
  • ->Move tray in
  • ->Please wait (wec is performed)
  • ->Adjust wafer using the 3 micrometer spindles (x axis, y axis and theta)
    • Click on Scan Optics.
    • Note the screen will go out of focus because the mask was loaded, just adjust it (using the joystick).
    • Click in field with left button to activate zoom (1X,2X,4X). This is just a zoomed in view, nothing can be adjusted in this zoomed in mode.
    • Press "Sep/Cont" button to go in and out of contact to check alignment and readjust (contact has the light off button and separate has the light on).
    • When satisfied with alignment you must remember to leave it in contact mode (if not poor exposure will result
  • Press <CONTINUE> when wafer is aligned
  • ->Please wait
    • If Hard Contact was selected you will be prompted to set the pressure and press continue (0.5 bar is the correct setting (up to 1.5 will work).
    • If vacuum contact is selected you will be given the option of pressing continue to expose OR pressing Undo if you want to do more alignment (view is of wafer in vacuum mode - last chance to back out before exposure)
  • Exposure time is announced and exposure begins.
  • ->Please Wait
  • ->Move tray out
  • ->Remove substrate and press CONTINUE.
  • ->Insert substrate and press CONTINUE.
    • Now either load a new substrate or see below to unload the mask.
  • Do not disable the EV aligner before completely finishing the following Shutdown Procedure! Otherwise the system will jam!

  Shutdown Procedure

  • Click "EXIT" or"UNDO" to unload mask.
  • >Insert load frame and move tray in
  • ->Please Wait
  • ->Move tray out
  • ->End of process - remove load frame
  • Click on EXIT
  • Select Park. Move tray in? Click on yes and move the tray in.
  • Leave Key ON
  • Leave PC Power on.
  • Click on Logout
  • Disable "evalign" (log resist type, thickness, exposure time, result on log sheet)

Button Information

Button Description
Limits Choose Scan Optic
Scan Optic

To move with the split field microscope. In addition you see the minimum, maximum and actual value of the left and the right microscope in X, Y and Z direction. With "Store Optic Pos" you can store the actual optic position. With "Load Optic Pos" you can load a stored optic position.

Recipe To set process data during the process
Controls To change the cross data and overlay intensity (in case of topside alignment you do not have a cross.)
continue Usually acknowledges previous choice or that what is on screen is done. Also may push <ENTER> button for same result (button with arrow down and to the left)
enter Confirms data entry
Track Ball Used for PC control
Joystick Adjust split field microscope in X and Y (right and left, forward and back)and to focus (rotate clockwise or counterclockwise). Speed controlled by slow or fast movements.
L/R: To change between left and right objective
Sep/Cont: To change between separation and contact
Undo: If you have a problem press "Undo" to go one process step back, and follow instructions on screen.
Stop: To stop the process
Exit: To leave the process
Wec Force: Check pressure during WEC only, cover weight can be adjusted.(0.4 bar)
Exposure Force:

Check pressure during align phase (0.5 bar).

Chuck Weight: Is actual pressure during WEC (270 -300 mbar)
Hard Contact: When hard contact mode is selected you can adjust N2 pressure (0.5 bar)

Special Notes

Lamp can not be restarted when key is turned on.

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