Ultra-pure wet chemicals: Characteristics
What parts per trillion purity looks like in practice
What this tab covers The physical and chemical properties that set its grade, price and uses, with the commercial grades and the standards that define them.Purity is the product: metal content, particle counts and anion levels decide the grade and price. SEMI standards define grades; leading-edge logic needs the highest. Consistency between lots matters as much as the average.
Properties that matter commercially
| Property | Value / specification | Why it matters | Source |
|---|---|---|---|
| Metal impurities | SEMI Grade 5: about 10 ppt or less per metal (indicative) | Metals on wafers cause defects and leakage | SEMI C-series standards (indicative) |
| Particles | a few particles above 0.05 micron per ml (indicative) | Particles kill dies | Indicative |
| Assay | H2SO4 96%; H2O2 31%; HF 49%; NH4OH 29% (common electronic concentrations, indicative) | Standard process recipes | Indicative |
Commercial grades
- SEMI Grade 1-5 (ppm to ppt)
- Electronic-grade sulphuric acid
- Electronic-grade hydrogen peroxide
- Electronic-grade HF and BOE
- Electronic-grade ammonium hydroxide, HCl, phosphoric, nitric
- Electronic-grade IPA
- TMAH developers