Resist spin coating

How to behave

• Always think of safety first!
• Wait patiently for the previous user to finish their process in the spin coater and then you can start using the fumehoom.
• Minimise the duration for which the resist bottle stays open (without a lid).
• Clean the spinner and the chuck until there are no resist marks left
  • Use 1,3 Dioxolane for e-beam resists
  • Use Acetone for photoresists
• Is a resist missing? Not it in the whiteboard in the gowning area.

How to spin coat

Set up your workspace

• Log your process in the designated Google-Sheets file (date, name, resist stack):
  • CR1: PC with Olympus microscope
  • CR2: PC with Olympus microscope
• Take the resist bottle from the cabinet
• On a cleanroom wipe, write your name to let users know who is using the fumehood
• Choose the correct chuck with respect to your chip size

Depending on the smallest dimension of your chip use the recommended chuck:

• <5mm: small chuck
• 6-10mm: medium chuck
• >10mm: large chuck
• 2-inch wafers or larger: No chuck

Spin resist

• Place the chuck on the stage
• Place your chip on the chuck
• Center your chip and press Vacuum
  • If you think that your chip is not centered, repeat this step
• Choose a spinner recipe
• Close the lid
• Choose a pipette
  • Hold the pipette with one hand
  • With the other hand, open the resist bottle
  • Squize a sufficient amount of resist
  • Close the resist bottle
  • Deposit a sufficient amount of resist on your chip via the hole on top of the lid
    • You should cover the entire chip surface
    • Avoid the formation of bubbles
    • You should be able to observe surface tension from the resist liquid on top of your chip
    • You should stop pouring resist before the surface tension collapses and the resist spills on the sides of your chip
• Play the recipe

Cleaning and baking

• While your recipe is running:
  • Return the resist bottle to the designated place in the cabinet
  • Set the timer for baking

• AZ photoresists: 115°C for 1 min
• e-beam resists: 185°C for 2 mins

• Once your recipe is done, open the lid
• Press Vacuum to disable the vacuum from the back of your chip
  • If you spin resist on a large wafer, open the lid slowly. Resist residues from the lid sides may fall on your sample, ruining the coating.
• Transfer your chip to the hot plate for baking and start the timer
• Start cleaning the spinner
  • You should spend a significant amount of time cleaning the spinner
  • Clean the chuck
  • Clean carefully inside the spinner (at the bottom and inside the lid)
  • Don't forget the top hole

Cleaning chemicals for each the resist series:

• 1,3 Dioxolane: CSAR, ZEP, LOR
• Acetone: PMMA A, EL, AZ,

• Remove your sample from the hot plate and store it in your sample box
• Keep cleaning the spinner until it is spotless
• Log your cleaning in the Google-sheets (cleaning agents, comments)
• Tidy up the fumehood for the next users
• Continue with the next steps of your process