Godin:Protocols/Mask aligner

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Mask aligner

OAI Model 200 mask aligner

Operation Procedure

WARNING: This machine exposes users to ultraviolet radiation. Do not touch the lens underneath the lamp hood as it may damage the machine and cause severe burns. Exposure to pressurized gas, high voltage electricity and mercury vapor may result from improper use of this equipment. Recommended Apparel: Eyewear rated to 400nm, clean room suits and nitrile gloves are required and mandatory in this lab environment.

1) Check that the primary systems are connected to a wall outlet and that any power strips or surge protectors in their path are activated.

2) Verify that the vacuum and compressed gas feeds are turned on.

3) Move the microscope platform to the back of the tabletop and mask aligner platform completely to the right by using the black pressure buttons.

4) Make sure that the exhaust fan in the lamp hood is now on, the barrier of venting tube is open up to the red lines before continuing to the lamp warm up. The attached gauge should be between 0.15 and 0.25.

Warm up Procedure:

1) Power on the constant intensity controller, using the large switch.

2) Briefly depress the Start switch to turn the lamp on; you will hear a clicking sound. WARNIG: the lamp shutter could go off itself when lamp turns on so be ready to press “Reset” by putting your finger on the button and looking away from the lamp when depressing Start switch.

3) Allow the lamp to warm up for about 30 minutes before moving on. Please take this time to work through the mask, substrate and alignment procedures.

Mask Placement:

1) Make sure that the mask is cleaned of particulates before installing. Ethanol works great.

2) Loosen the two screws on two sides in front of the mask assembly and remove any placeholder material.

3) Place the mask underneath the clamps with the emulsion side down and push it flush against all three alignment pins.

4) When the mask is in place, tighten the placement screws enough to mitigate movement but not so much that they bend the surface.

WARNING: Do not overtighten these screws. You WILL break the glass. These are merely to keep things in place until a vacuum is applied later.

5) If the mask is set at an angle to the front of the module then loosen the thumbscrews on either side of the frame to rotate it until it is parallel to the front of the machine.

6) Push in the Mask Vacuum button to affix the mask to the frame. You’ll want to make sure that the screws don’t prevent the mask from contacting your substrate. Make sure it’s roughly centered.

Substrate Placement:

1) Move the microscope arm to the far back corner of the bench and then the mask assembly to the far right. The microscope has two movement handles so be sure to use the one closest to the surface of the table top. The mask frame will not open if the microscope is near it.

2) Flip the Mask Frame switch to the Open position and it should automatically rise about 40º. If the frame does not open immediately then recheck that the microscope/mask assemblies are in their proper storage positions.

3) Once the frame is open, place the substrate chip in the middle of the vacuum chuck completely covering the + sign in its center.

4) The chip, like the mask, should be set parallel to the front of the aligner.

5) Use the Sub. Vac switch to secure the substrate to the mask aligner.

6) Close the mask frame.

Mask Alignment:

1) The microscope should not hit the mask frame when it is in use so adjust the height accordingly.

2) Move the mask assembly slightly to the left so that it is lines up with the microscope.

3) Using the lower movement handle on the microscope arm to pull it forward above the mask.

4) Flip the Ball Vac switch to the unlock position to allow for rising of the substrate.

5) Use the control handle on the upper arm of the microscope assembly to orient the microscope more precisely. The top and bottom buttons allow for small modifications in the Y and X direction respectively. Be careful when using these controls because the light and power sources may get damaged or disconnected if this piece too quickly or far from their initial position.

6) Adjust the microscope till the mask can be seen with both eyes and then focus the optics as needed. The lowest magnification is good for setup and to finding alignment features because it has the best field depth and view. Once the microscope is in focus it will remain that way regardless of magnification changes. Note that the left knob is used to hold the microscope in place vertically,the right one is used to move it up or down. You’ll need to use both simultaneously while adjusting focus.

7) Turn the black knob on front of the alignment module (not the Chuck Z Adjust) and view the substrate raising and leveling through the microscope.

8) Once the substrate reaches the mask a significant resistance will be felt in the knob, the belt will stop moving and the chuck should become level.

9) Lock the Ball Vac into position and prepare for final alignment.

10) Use the three long stemmed adjustment bars around the outside of the assembly to lower and then precisely align the substrate and mask. The middle bar controls the Y-Axis, the right controls the X and the far left controls rotation. The movements are on the scale of micrometers so it is most beneficial when the microscope is in focus during these adjustments.

11) Raise the substrate with the previously used black knob until contact is made. This is known as making soft contact. The hard contact switch can be thrown to increase resolution but it will cause a residue to form on the mask after exposure.

12) Turn on the Contact Vac to lock in the final changes and prepare for exposure.

13) Rotate microscope lens to the empty compartment and carefully return the arm to its storage position, this can probably be done without changing the elevation of the arm.

14) Turn off the alignment optic power unit.

Exposure: *All recommended apparel should be used in this section.*

1) Set the timer to the desired exposure time. There are two time scales, the 100 and 1000. Make sure you’re using the right one, and that input time is correct.

2) Move the assembly completely underneath the hood to activate the lamp. To avoid severe burns, do not touch the lamp or hood while in operation or shortly thereafter.

3) Wait for the lamp to finish its exposure and then move the assembly back to its alignment position.

After Exposure:

1) Turn off the Hard Contact switch if it was used during the exposure.

2) Turn off the Contact Vac. Adjust switch.

3) If the substrate is sticking to the mask then turn on the Nitrogen Purge switch and open the Nitrogen Purge Flow Valve for 5-10 seconds to break the adhesion.

4) Lower the substrate from the mask using the black knob to avoid accidental contact in later trials.

5) Check that the alignment optics are in storage position.

6) Open the mask frame and turn off the Sub. Vac.

7) Carefully remove the substrate and then close the mask frame.


1) If the lamp is no longer needed then turn off the power switch on the constant intensity controller.

2) Close the vacuum valve and compressed gas.

3) The lid of exhausting fan MUST keep opened for a while (at least 10 minutes) so the lamp cools down. It should be closed afterwards.

4) Do not forget to turn off the system.