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Center of MicroNanoTechnology CMi

Photolithographic cluster EVG150

 

EVG 150 - Automatic Resist Processing Cluster

General description

The individual processing stations are fed by a central robot arm. The EVG150 cluster at EPFL can process standard silicon wafers or transparent substrates from 100mm to 150mm. The machine is available for positive photoresist coating, softbake, PEB (post exposure bake), hardbake and development.

Specific Modules

Cassettes
Two stations for standard cassettes of 25 wafers. Default standard configuration is for 100mm cassettes only; separated for coating and development.
Per request, 150mm cassettes are available.


Status light

A light tower is installed behind the upper left corner of the front window:

  • Red blinking = Error is detected, process cannot continue
  • Middle Yellow Continuous = Automatic mode on
    Blinking = Process paused or stopped
  • Lower Green Continuous = Initialization complete, normal state
    Blinking = Initialization in progress

 

Robot with with 3 vacuum suckers("endeffector")

  • Large fork = 100 and 150mm wafer size

 

Flat aligner
  • Top optical edge detection for alginment and centering of wafers. Semi-transparent wafers are also detected.
  • Fully transparent wafers are not recommended (large sensitivity to edge defects).

 

Hotplates with programmable proximity and temperature setpoint
  • Hotplate for high temperatures up to 350ºC (1x)

 

 

 

  • Hotplate standard up to 150ºC (2x)
  • N2 purge or low vacuum mode is available.
  • li>

 

Coater module features
  • Spinner chucks for 4'-6'' wafers.
  • Main dispense arm with permanent lines, 2 resists, 2 edge bead removal (EBR) and motorized syringe.
  • Second dispense arm with spray coating head.
  • 2 back side rinse nozzles.
  • Cover with nozzles for automatic bowl wash system.

 

Developer module features
  • Dual puddle and spray dispense of developers. 2 devolopper lines availble 2 back side rinse nozzles.
  • DI water rinse.

 

Cool plate
  • Passive system for rapid cooling of substrates to room temperature.


 

Checklist before starting

Recipe for coating and developments are available by selection on the graphical user interface menu "open". Recipes are stored in database library, each photoresist has is own library to be loaded first. Thicknesses and edge bead cleaning can be selected within each library. A copy of the library can be stored (localy on the HD) in a specific user folder.

1) Reservation rules and booking fee policy

Reservation fees are applied for this equipment.

2) Verify machine configuration

Note: 4 photoresist dispense lines are connected:

3) Prepare wafers

Perform appropriate surface preparation steps (dehydration, HMDS coating, ...) based on process flow. Make sure to finish before reservation starts.

 

Operation

1) Login on the CAE terminal

Login is required to use the system. If system is not enabled, error message will show on display.

 

2) Login on equipment

  • Click on the “Login Here” button (bottom left corner of main window)
  • General user access parameters:
    ID=0000; PW=0000
  • After successful login the following sections will appear on display: Recipes, Jobs, Pumps, Tanks, Low IO Terminal.

 

3) Chose one application library

Several application databases are stored in the system. Each file is a unique set of recipes for use with a specific configuration and resist type. Databases are optimized for a specific photoresist type and substrate type combination. Thicknesses can be chosen within these databases.

  • Verify the name of library in the title of the software window
  • Library under Recipes (Standard library) are write protected
  • Library under Recipes/Library (Advanced library) are write protected
  • Recipes/Users level is free for read/write . Please create your own folder at this level for backup or modified recipes.

For transparent wafers without any deposited layer use a "Glass Only" certified recipe (see also information note processing with transparent wafers).

Note: as long as the same database is selected, coating and development can be run in parallel.

 

Use the "Open" window from the top menu of the software, and start from the folder
Application library directory tree start at

C:/...EVG/EVG150/Recipe

4) Verify your recipe

The Recipes tab shows the actual recipes database with the complete hierarchy. Station recipes are grouped under corresponding station names in subfolders. The user executable recipes are at the top level (bottom of hierarchy tree).

Hierarchical tree:

  • Subprograms are in subfolders categorized by stations. These are called from the main programs by links.
  • Master recipes are executable (listed at bottom) describe the process flow for a wafer.

 

Example of master recipe

Subprograms list step by step parameters related to an individual station.

 

5) Check for liquid levels

Chemicals can be monitored using the "Pumps" and "Tanks" tabs. If a low level is reached, the recipe will not run and the process will be stopped.

  • A warning message window will appear on all tab screens at 5% level.
  • An alarm shows at 0% level and will stop processes.

Note: the machine levels are verified on a daily basis. If levels are low, notify staff before proceeding.

 

6) Check for errors

Schematic under “Job” screen is shown on right.

  • Click with the left mouse button on each station to get a user menu
  • Status bar at top will turn red and indicate possible error conditions. Clicking on this bar with the mouse might clear the problem in some simple cases.

Terminal window (bottom) shows history of all high level user communication.

 

7) Start Batch Run

Load cassette on left dock station for coating (cassette 1) or right dock station for developing (cassette 2)

  • If necessary, tilt the station by right clicking on the corresponing cassette and select "Tilt cassette"
  • Center the wafer carrier sliding down the cassette

 

 

 

 

 

 

 

 

8) Turn production mode on

  • Press "Start" on the top left of display
    (yellow light will be turned on).
  • Short initialization follows

 

  • Status bar will change to “Load a cassette” when system is ready. Right click on cassette to get the load menu.
  • First, choose your master recipe to run.

 

  • Second, choose slots to be processed on the second tab.
  • Critical level for resist dispense is updated according to the number of wafers to be processed.

     

    System ask a confirmation of wafersize. This message can be aknowledge. Press "OK"

    (historically small size adaptors needs to be checked)

     

    9) Atomatic processing is started

    • Hotplates temperature adjustment will start if necessary
    • Check of available liquids
    • Automatic dispense nozzle purge
    • Colors for slots are:
      Yellow = Waiting for process
      Red = In process
      Green = Process is finished

      Light blue = Wafer handling failure.

    It is possible to interrupt the process if necessary:

    The Pause and Stop buttons will pause or stop the main wafer flow in a safe way (recommended).
    Pause will stop loading wafers untill start is pressed agian.
    Stop will stop loading. Resume of current batch is not possible after that.

    In both case wafers inside the tool will be processed to the end of current recipe.

    Abort button will cause immediate abort of all current process in all station without possibility to restart (not recommended).
    After aborting, a “Clean-up” is necessary to continue.

    DO NOT PRESS ABORT WHEN A WAFER IS ON THE ROBOT ARM OR ON THE PRE-ALIGNER UNIT. THIS CAN CAUSE DAMAGE TO THE ROBOT.

    Wait until the wafer is loaded into a station (coater, developer, HP, or CP) before clicking “Abort” if it is really necessary to abort the process. Note that restarting the tool with a clean-up after "Abort" will cost more time than using "Stop". In many case clean-up fails after aborting. Thus tool will be locked and only staff member can reset and clean for errors.

     

    In case of a prealignment error:

    an error message with “RETRY” as option is proposed. BE CAREFUL, make sure the station is clean; otherwise a collision will happen with the next wafer. Remove manually the wafer from the alignment station before trying to continue.

    (See also information note processing with transparent wafers)

     

    Handling error or restart after "stop". In case a system clean-up is required, pay attention for each step and answer correctly to the questions asked by the system.

    Load an empty cassette to proceed, and select accordingly:
    Large Endeffector = 100 and 150mm wafer
    Small Endeffector = not installed

     

    10) Batch is finished

    • Main status bar turns green and cassete tilts for unloading
    • A new batch can be started from an idle cassette any time (simultaneous coating and development in parallel is possible)
    • Press "Stop" button in the top left if necessary, to access other menus or change recipe family

     

     

    11) Logout from equipment and access

    • Unload cassette and remove wafers. Return cassette on the loading station.
    • Cartridge. In case of Spraycoating reload the default cartridge in the system.
    • Clicking on the login icon key will end the session.
    • Log out on the CAE terminal.

    Note: under any circumstances, do not exit the application or the windows session. The system will not function if restarted. Staff is required to initialize the tool.

     

     

    Notes

    Automatic Bowl wash.

    To clean the bowl, load a dummy wafer into the loading cassette, and right click on the bowl, then select "Bowlwash". The wafer will load and return automatically if the step is finished. The procedure takes only a few minutes. If not sure, call staff.

    Frequency of coater cleaning:

    Process

    Action
    Frequency
    Spin coating with Cybor 1 or Cybor 2 AZ nLoF from the positive syringe line


    Automatic bowl wash can be performed Done at beginnig of the day,
    or when absolutly necessary (can overfill photoresist waste canister)
    Spray Coating

     

    Wash Spray Unit Immediately after batch is finished.