- Hydrofluoric acid (HF) is a corrosive that is used extensively in semiconductor processing. Primarily for the etching of silicon dioxide.
- Ammonium Fluoride is also a corrosive that is used in the etching of silicon dioxide. Ammonium Fluoride is the main component of Pad Etch.
- BOE or Buffered Oxide Etch contains both Hydrofluoric Acid and Ammonium Fluoride.
- Pad Etch contains Ammonium Fluoride and is used for etching silicon dioxide deposited over aluminum.
- Freckle Etch contains Fluoroboric Acid and is used for etching silicon nodules remaining after aluminum etch.
- Special precautions are needed for the safe handling of HF, NH4F, BOE, and Pad Etch and Freckle Etch.
They should all be considered as toxic and should never come in contact with the users skin.
Immediate treatment is required should this occur.