1. Make sure fume exhaust is operational.
  2. Clean the substrate, mask, and spinner bowl

  3. Dry the substrate:

    • 3-5 minutes at 120C on hotplate (or 30 minutes in 120C oven)

    • OPTIONAL: for oxides, pipette on a small amount of HMDS (just enough to cover wafer), puddle 5 seconds, then spin (5s@900RPM, 60S@4000RPM, check vacuum before spinning)

  4. Spin on photoresist:
    • Center sample on spinner and check vacuum.
  5. 5 seconds at 900 RPM (this clears excess resist to avoid splash-back)

  6. 60 seconds at 4000 RPM (1.3 micron film)

  7. Softbake the resist:
    • 3 minutes on hotplate at 100C (or 30 minutes in the 100 C oven) Note: alternative softbake at 90C will increase resist sensitivity, requiring shorter exposure times.

  8. Align and expose using Karl Suss MJB 3 UV400 mask aligner:
    • Broadband G,H,I-line: 436nm, 405nm, 365nm (make sure 365m I-line filter is not in path and lamp control on CI-2),
    • about 8 seconds at 18mW/cm
2 controlling intensity (CI2=405nm). This dose, ~140 mJ/cm all lines 2 may need to be optimized for your substrate (e.g. up to 3* that dose is required over Cu). S1813 datasheet shows 82mJ/cm2 at 435nm as threshold for complete exposure (somewhat less sensitivity to shorter wavelengths included in our source).

  • Develop:
    • Puddle MF319 developer for 60 seconds (pattern usually shows in 5 seconds)
  • Spin rinse with DI water 35 seconds at about 300 RPM

  • Spin dry 60 seconds at 3000-4000 RPM, with a burst of nitrogen gas in the center of the sample.

  • postbake:
    • 3 minutes on hotplate at 120C (or 30 minutes in the 120 C oven)

    S1800 series photoresist DATASHEET

    Photolithography Process Overview