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optical_lithography

Description

Warnings

  1. Don't make mess, clean everything after use.
  2. Switch off the lamp of the mask aligner, it has a limited lifetime.
  3. It is not allowed to take masks out of the cleanroom.

To start

  1. Because the UV lamp needs some time to warm up, you should switch on the mask aligner first.
    1. Switch on power and UV source.
    2. Wait for 10 minutes.
    3. In the meanwhile you can spincoat resist and bake it.
  2. Switch on the hot plate now (there is a switch at the left).
  3. Adjust temperature with large knob.
  4. Desired temperature depends on the kind of resist you use.

Hot plate

  1. put the sample on the hot plate and time the process.
  2. the time you need depends on the kind of resist.

Mask aligner

  1. When you can see the blue light shining from the back, the lamp is warm.
  2. Put the mask in the mask holder, upside down, because in this way the side with the structure on it will be in contact with your sample.
  3. Slide the mask holder in the mask aligner and switch knob 'mask'.
  4. Put your sample in and align roughly.
  5. If you want to know the dimensions of the structures, you can find schemes of the most frequently used masks on the spin coater bench ('tsutomu' mask, 'cip' mask and 'hall' mask).
  6. There are two handles at the left. The lower one should be set to 'contact'.
  7. Now you can turn the upper one.
  8. If the sample is not perfectly aligned, you can set the lower handle to 'separation' and adjust.
  9. When everything is OK, set the handle to 'contact' again.
  10. The exposure timer should be set to 15 seconds.
  11. Press exposure button and help the system a little bit if it doesn't move by itself.
  12. After exposure, turn left knob and remove sample.

Development

  1. Fill a glass with developer (which one depends on the resist) and one with water.
  2. Develop (usually 20-30 seconds).
  3. Rinse in water.
  4. Dry with N2 and be careful not to damage your structure.

When you're done

  1. Switch off the lamp of the mask aligner and the mask aligner itself.
  2. Switch off the hot plate.
  3. Clean the spin coater.
  4. Clean up the glasses you used for the developer. It is not necessary to put developer in the waste bottle.
  5. Fill in the log book.

Resists

Resist Spin coater Baking Developing Remarks
AZ5214E 4000/6000rpm 90 C, 2.5 min 50% AZ312MIF + 50% H2O, 40 s -
HPR205 4000/6000rpm 90 C, 2.5 min 50% AZ312MIF + 50% H2O, 40 s -
MaN1410 3000rpm,30-45 s 90 C, at least 90 s MaD533, 15 s negative photoresist
MaP1205 4000/6000rpm 100 C, 30 s 90% MaD532 + 10% H2O, 30 s 100% MaD532 can also be used, takes 10-15 s

Removing resist after etching and lift-off can be done in acetone.

Mask fabrication

The mask aligner uses 2.5“ masks. We order 5” masks in Twente so that's 4 2.5“ masks. You can design masks with the program clewin. Click on the link to get it: clenwin.zip

Technical stuff

Lamp type: 030W7 HBO 200W mercury vapor lamp

optical_lithography.txt · Last modified: 2019/10/08 09:41 by scholma

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