Polysilicon Etching

In practical applications, polysilicon etching is commonly performed using a mixed solution composed of nitric acid (HNO₃), hydrofluoric acid (HF), and acetic acid (CH₃COOH). The etching process involves two primary chemical reactions:

1. Oxidation of polysilicon by nitric acid:
   Si + 4HNO₃ → SiO₂ + 4NO₂ + 2H₂O

2. Removal of the silicon dioxide (SiO₂) layer by hydrofluoric acid:
   SiO₂ + 6HF → H₂SiF₆ + 2H₂O

First, HNO₃ is used for its strong acidic properties to oxidize polysilicon into SiO₂. Then, HF is used to remove the SiO₂ layer, while CH₃COOH acts similarly to a buffer solution, providing a source of H⁺ ions to maintain a stable etch rate. This mixed solution, commonly referred to as “Poly-Etch”, is also widely used in monitor wafer reclamation.

Poly silicone etch normal used mixture of nitric acid(HNO3) and hydrofluoric acid(HF) in water or acetic acid(CH3COOH) ,
1.HNO3 oxidizes the silicone to form an SiO2 layer, 
2.HF used to dissolve and removes the oxide layer (SiO2) at the same time, 
3.DI and acetic acid can be used to dilute the etchant, and reduce the etching rate, but the acetic acid is preferred  
 Si + 2HNO₃ + 6HF → H₂SiF₆ + 2NO₂ + 2H₂O

Packaging type：200L drum