Koch Lab:Protocols/Photolithography

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"->" denotes physically pushing the button on the machine with the text that appears directly after symbol.

General Outline of process

  1. Spin
  2. Pre bake
  3. Expose
  4. Post bake
Hot plate for prebaking


Preheat hotplate for prebaking wafer

  • ->set
  • ->plate temp
  • ->"Desired temp"
    • ->9
    • ->5
  • ->ent
Spin coater
Nitrogen knob
UV exposer
Developing wafer

Applying photo resist

  1. Place wafer on spin coating machine
    • ->speed (input speed)
    • ->accel (input acceleration)
    • ->time (input time)
    • ->save->back
    • ->run process
    • ->load recipe
    • ->"file name"
  2. Manually center wafer by "eyeballing" it (this may take several tries)
  3. Turn on vacuum pump (manually)
    • ->center
  4. Manually adjust wafer if needed (repeat previous 2 steps until wafer is centered sufficiently)
  5. Poor photo resist on the top side of the wafer
    • ->spin
    • ->ok
      • NOTE: bubbles on wafer are normal
  6. Move wafer to hot plate
    • wait 15 minutes
  7. Hook up vacuum hose to UV exposer
  8. Turn on Nitrogen
  9. UV exposer
    • Pull white lever
    • ->start
    • wait for 200W
    • ->Power
    • ->visual align
    • Tape mask onto glass (place glass side up)
      • ->mask clamp
    • Load wafer on tray below
      • ->chuck vac
    • Push slide in
      • ->mask load
      • ->visual align
      • ->wafer load
      • ->cont (pushes wafer against mask)
    • Set time
      • ->manual expose
    • ->chuck vac
    • remove wafer
  10. Post bake (5 mins)
    • ->mask load
    • ->mask clamp
  11. Take off slide
  12. Turn everything off!!!
  13. Place wafer in glass dish
    • NOTE: It is imperative that glass is used, if a petri dish is used the developer with fuse the wafer to the dish.
  14. Poor in developer (6 mins)
  15. Take wafer out of developer
    • At this point you can spray the wafer with ethanol to remove residual developer
    • Can also use Nitrogen gas to blow off fluid/debris from wafer
  16. Dispose of developer in designated bottle under fume hood.