Ultra Pure Chemicals
Acids
Phosphoric Acid 86%; 80%
The etching of silicon nitride and oxide is included among the main applications of Phosphoric Acid. When processed in a refluxing system at 150° -180°C the product has a selectivity ‘‘Nitride: Oxide '' of greater than 20:1. In addition, Phosphoric Acid combined with Nitric and Acetic Acids may be used to etch aluminium layers. Other applications include the uniform etching of the back of silicon wafers with mixes of Phosphoric Acid, Sulphuric Acid and Surfactants. The controlled smoothing of silicon surfaces with acceptable selectivity to PSG oxides when using combinations of Phosphoric Acid and Ammonium Fluoride.
Market Segments:
Functions:
Etchant