Photolithographic Process for S 1805 Positive Photoresist on Bare Silicon Wafer

  1. Clean Wafers with the Piranha Etch Bath.
    1. Heat bath to 80 °C.
    2. When bath is at temperature, place wafers in bath using Teflon boat and start 20 minute timer.
    3. When time is complete, take wafers out of piranha etch and place in dump washer being careful to avoid any drips of sulfuric acid. Start the timer on the dump washer.
  2. Clean and Dry Wafers in Semitool SPD015 Spin Dryer
    1. Upon completion of dump washer, place wafers in spin dryer and press start.
    2. When done transfer wafers to different carrier boat.
  3. Apply Adhesion Promoter, HMDS, to Wafers Using Vapor Prime Oven
    1. Transfer wafers to HMDS brown Teflon boat and place in orange vapor prime oven.
    2. Make sure the gasket is properly secure and press ‘Run’ button.
    3. Upon completion of HMDS bake, about 30 minutes, let the wafers cool to room temperature.
  4. Spin Coat Wafers with S1805
    1. When wafers reach room temperature, load a wafer on a prepped Headway or Brewer spin Coater.
    2. Choose the proper recipe, recipe 5 for the Headway spinner and recipe 6 for the Brewer spinner, and press start. Resist spun at 5000 rpm to give a thickness of about 500 nm.
    3. Dispense S 1805, about 6 mL per 4” wafer, during the spin coating.
  5. Soft Bake
    1. Soft bake for 1 minute at 115 °C on a vacuum hot plate.
  6. Expose Wafer in the Contact Aligner
    1. Expose for 2.2 seconds without any filter for optimum exposure dose. Channel A of the contact aligner is set at 15 mW/cm2.
  7. Develop Wafer
    1. Develop wafer for 45 seconds in AZ 726 MIF Developer.
    2. Wash with deionized water to completely remove developer, and blow dry with nitrogen gun.
  8. Hard Bake
    1. Hard bake for 3 minutes at 115 °C on a vacuum hot plate.

Attached Documents