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Electrical & Computer Engineering
Integrated Microfabrication Lab
Machine Scheduler

AZ 3330 Adhesion to Glass

Working with AZ 3330 on glass surfaces can be difficult without proper surface treatment. AZ 3330 photoresist features (especially small features) on the glass or borofloat wafers will usually be damaged, deformed, or even nonexistent if the photoresist adhesion process is not done properly. Below are three possible photoresist adhesion processes listed with the most successful method first.

Procedure 1: RIE Carbon Tetrafluoride Etch

  1. Immerse wafer for two minutes in nanostrip at 90 degrees Celsius, remove, and rinse thoroughly in deionized water
  2. Etch wafer in a Reactive Ion Etcher (RIE) for 30 seconds at 75 mT and 150W using Carbon Tetrafluoride gas
  3. Put wafer in a dehydration bake oven set at 120 degrees Celsius for thirty minutes
  4. Use a swab to cover the wafer surface with Surpass 4000, let it stand 30 seconds, rinse in DI water, and dry
  5. Spin on AZ 3330 for 1 min at 2750-6000 rpm depending on desired thickness
  6. Bake for two minutes on a hot plate set at 90 degrees Celsius
  7. Expose for 8-10 seconds, develop for 30-40 seconds
  8. Bake for two minutes on a hot plate set at 90 degrees Celsius

**If reflowing:** Bake on a hotplate with the temperature set to 90 degrees Celsius Ramp the hotplate temperature from 90 to 250 degrees Celsius Bake at 250 degrees Celsius for 20 minutes

***Warning:*** Let wafer cool slowly. Letting a hot wafer get wet will shatter the wafer.

Procedure 2: Buffered Hydrofluoric Acid Etch

  1. Immerse wafer for two minutes in nanostrip at 90 degrees Celsius, remove, and rinse thoroughly in deionized water
  2. Etch wafer in Buffered Hydrofluoric acid (BHF) for 30 seconds
  3. Put wafer in a dehydration bake oven set at 120 degrees Celsius for thirty minutes
  4. Use a swab to cover the wafer surface with Surpass 4000, let it stand 30 seconds, rinse in DI water, and dry
  5. Spin on AZ 3330 for 1 min at 2750-6000 rpm depending on desired thickness
  6. Bake for two minutes on a hot plate set at 90 degrees Celsius
  7. Expose for 8-10 seconds, develop for 30-40 seconds
  8. Bake for two minutes on a hot plate set at 90 degrees Celsius

**If reflowing:** Bake on a hotplate with the temperature set to 90 degrees Celsius Ramp the hotplate temperature from 90 to 250 degrees Celsius Bake at 250 degrees Celsius for 20 minutes

***Warning:*** Let wafer cool slowly. Letting a hot wafer get wet will shatter the wafer.

Procedure 3: RIE Oxygen Etch

  1. Immerse wafer for two minutes in nanostrip at 90 degrees Celsius, remove, and rinse thoroughly in deionized water
  2. Etch wafer in a Reactive Ion Etcher (RIE) for 30 seconds at 75 mT and 150W using Oxygen gas
  3. Put wafer in a dehydration bake oven set at 120 degrees Celsius for thirty minutes
  4. Use a swab to cover the wafer surface with Surpass 4000, let it stand 30 seconds, rinse in DI water, and dry
  5. Spin on AZ 3330 for 1 min at 2750-6000 rpm depending on desired thickness
  6. Bake for two minutes on a hot plate set at 90 degrees Celsius
  7. Expose for 8-10 seconds, develop for 30-40 seconds
  8. Bake for two minutes on a hot plate set at 90 degrees Celsius

**If reflowing:** Bake on a hotplate with the temperature set to 90 degrees Celsius Ramp the hotplate temperature from 90 to 250 degrees Celsius Bake at 250 degrees Celsius for 20 minutes

***Warning:*** Let wafer cool slowly. Letting a hot wafer get wet will shatter the wafer.