In semiconductor manufacturing, where extreme precision and cleanliness are paramount, semiconductor-grade phosphoric acid is used. This grade of phosphoric acid is subjected to rigorous purification processes to ensure high purity levels, typically above 99.999%. Contaminants such as heavy metals, organic impurities, and particulate matter are carefully removed to prevent any adverse effects on semiconductor manufacturing processes.
| Electronic Grade Phosphoric Acid | |||
| Assay（H3PO4） | 85.4-86 % | Color | ＜10 APHA |
| Substances Reducting(as KMnO4) | ≤10 ppm | Volatile Acids(as CH3COOH) | ≤10 ppm |
| Chloride (Cl) | ≤0.5 ppm | Sulfate (SO4) | ＜2 ppm |
| Nitrate (NO3) | ≤0.1 ppm | Fluoride (as F) | ≤2 ppm |
| Heavy metals | ≤1 ppm | Lithium(Li) | ≤3.5 ppb |
| Sodium (Na) | ≤9 ppb | Magnesium(Mg) | ≤5.3 ppb |
| Aluminum(Al) | ≤6 ppb | Potassium(K) | ≤2 ppb |
| Calcium(Ca) | ≤8.5 ppb | Chromium(Cr) | ≤4 ppb |
| Manganese(Mn) | ≤2 ppb | lron(Fe) | ≤16 ppb |
| Cobalt(Co) | ≤2 ppb | Nickel(Ni) | ≤8 ppb |
| Copper(Cu) | ≤4.8 ppb | Zinc(Zn) | ≤10 ppb |
| Gallium(Ga) | ≤2 ppb | Arsenic(As) | ≤7.2 ppb |
| Strontium(Sr) | ≤2 ppb | Silver(Ag) | ≤0.75 ppb |
| Cadmium(Cd) | ≤2 ppb | Stibium(Sb) | ≤38 ppb |
| Barium(Ba) | ≤2 ppb | Thallium(Tl) | ≤2 ppb |
| Lead(Pb) | ≤2 ppb | Boron(B) | ≤5 ppb |
| Titanium(Ti) | ≤2 ppb | Silicon(Si) | ≤4 ppb |
| Stannum(Sn) | ≤1.5 ppb | Gold(Au) | ≤2 ppb |
| Particles(>0.15µm) | ≤40 pcs/ml | Particles(>0.1µm) | ≤247 pcs/ml |
| Particles(>0.08µm) | ≤353 pcs/ml | Particles(>0.04µm) | ≤1629 pcs/ml |
| Alpha particle | ≤18 mBq/ml | ||
1.Surface Cleaning: Phosphoric acid is used to clean semiconductor surfaces before deposition or patterning processes. It removes organic residues, oxide layers, and other contaminants, ensuring proper adhesion and quality of subsequent layers.
2.Etching: Phosphoric acid is employed as an etchant in various semiconductor fabrication steps. It selectively removes specific materials or layers from semiconductor substrates to create desired patterns or structures.
3.Passivation: Phosphoric acid is sometimes used in passivation processes to create a protective layer on semiconductor surfaces, preventing unwanted reactions or contamination.
4.Surface Preparation: Before bonding or metallization processes, semiconductor surfaces often require precise preparation. Phosphoric acid can be involved in surface treatments to improve bonding or adhesion properties.
The high purity requirements for semiconductor-grade phosphoric acid necessitate stringent quality control measures throughout the production process. This ensures that the acid meets the strict specifications of semiconductor manufacturers and contributes to the reliability and performance of semiconductor devices.
