RCA-1 and RCA-2 Solutions: Standard Silicon Wafer Cleaning Process for Semiconductor Fabs
RCA-1 and RCA-2 Solutions: Standard Silicon Wafer Cleaning Process for Semiconductor Fabs
The RCA clean process consists of two steps: SC-1 (NH₄OH:H₂O₂:H₂O = 1:1:5 at 75-80°C, 10 min) removes organic residues and particles; SC-2 (HCl:H₂O₂:H₂O = 1:1:6 at 75-80°C, 10 min) removes metal ions (Fe, Na, Ca, Al). This is mandatory pre-treatment before oxidation, diffusion, and CVD in chip manufacturing. Loc Thien supplies NH₄OH, HCl, H₂O₂, HF electronic grade for RCA clean at FDI factories.
What is RCA Clean?
RCA clean is the standard silicon wafer cleaning process developed by Werner Kern and D. Puotinen at RCA Laboratories in 1965. The process includes two main steps: SC-1 (Standard Clean 1, also called RCA-1) uses NH₄OH/H₂O₂/H₂O mixture to remove organic residues and particles; SC-2 (Standard Clean 2, RCA-2) uses HCl/H₂O₂/H₂O to remove metal ions.
Werner Kern — RCA Laboratories, 1965
Werner Kern (1933-2017), German-American chemist at RCA Laboratories, published the wafer cleaning process using alkaline-peroxide (NH₄OH/H₂O₂) and acid-peroxide (HCl/H₂O₂) solutions in 1965. Before this, manual solvent cleaning methods lacked reproducibility.
SC-1 (RCA-1) — Organic Clean + Particle Removal
SC-1 uses NH₄OH/H₂O₂/H₂O at ratio 1:1:5, heated to 75-80°C for 10 minutes. The mechanism combines H₂O₂ oxidation of organic matter with NH₄OH dissolution, while zeta potential change repels particles from the wafer surface.
SC-2 (RCA-2) — Ionic Clean + Metal Removal
SC-2 uses HCl/H₂O₂/H₂O at ratio 1:1:6 at 75-80°C for 10 minutes. HCl forms soluble chloride complexes with metal ions (Al³⁺, Fe³⁺, Na⁺, Ca²⁺, Cu²⁺), while H₂O₂ oxidizes low-valence metals to higher valence for easier dissolution. After SC-2, metal residue <10¹⁰ atoms/cm².
Chemicals for RCA Clean at Loc Thien
| Chemical | CAS | Concentration | Grade | Application |
|---|---|---|---|---|
| NH₄OH | 1336-21-6 | 25% | SEMI Grade 2-5 | SC-1 |
| HCl | 7647-01-0 | 32-37% | SEMI Grade 2-5 | SC-2 |
| H₂O₂ | 7722-84-1 | 30-32% | SEMI Grade 2-5 | SC-1 + SC-2 |
| HF | 7664-39-3 | 49% | SEMI Grade | Oxide strip |
FAQ
What is the difference between RCA-1 and RCA-2?
RCA-1 (SC-1) uses NH₄OH/H₂O₂/H₂O at alkaline pH for organic and particle removal. RCA-2 (SC-2) uses HCl/H₂O₂/H₂O at acidic pH for metal ion removal.
How long does RCA clean take?
Total 30-40 minutes: SC-1 (10 min) + rinse (5 min) + SC-2 (10 min) + rinse (5 min) + drying.
Does Loc Thien supply NH₄OH electronic grade?
Yes. NH₄OH 25% (CAS 1336-21-6) SEMI Grade 2-5, total metals <1 ppb, lot-specific COA.
🛒 Need NH₄OH/HCl/H₂O₂ electronic grade? Get RCA clean chemical quote — lot COA, nationwide delivery to industrial parks. Hotline 0979 891 929.
