Substrate Cleaning

Simple Clean

1. Removes organic contaminants
2. Photoresist Stripper
3. Process
   
   1. Cover the surface of the wafer with Acetone.
   2. Thoroughly scrub the surface of the wafer with a swab.
   3. Rinse the wafer with IPA.
   4. Blow dry the wafer with N₂ gun.

O₂ Plasma Etching

1. O₂ plasma etching will remove organic films and residues. O₂ plasma etching can be done in the PE2.
2. Process
   
   1. Place the wafer in the PE2 chamber (you should have to vent it first).
   2. Vacuum down the chamber.
   3. Turn on the oxygen flow.
   4. Turn on the power to strike a plasma and wait for 30 sec to 5 min depending on how clean the wafer already is.
   5. Vent the chamber and remove wafer.
   6. Vacuum down the chamber before you leave.

RCA Clean

1. Removes organic, oxide, and metallic contaminants
2. Process
   
   1. Organic Clean: Removal of insoluble organic contaminants with a 5:1:1 H₂O:H₂O₂:NH₄OH solution.
   2. Oxide Strip: Removal of a thin silicon dioxide layer where metallic contaminants may accumulated as a result of (I), using a diluted 20:1 H₂O:HF solution.
   3. Ionic Clean: Removal of ionic and heavy metal atomic contaminants using a solution of 6:1:1 H₂O:H₂O₂: HCl.

Piranha Clean

1. Removes organic materials (photoresist, oil, etc.)
2. WARNINGS: Do not use Piranha clean on aluminum
3. Process
   
   1. Mix 98% H₂SO₄ (sulfuric acid) and 30% H₂O₂ (hydrogen peroxide) in volume ratios of 2-4:1
   2. Heat to 100°C