Octafluorocyclobutane Dielectric Etch Gas (c-C4F8)
CAS Number: 115-25-3
Octafluorocyclobutane (c-C4F8) is a fluorocarbon gas used as the primary dielectric etch chemistry for high-selectivity oxide and nitride plasma etching in advanced semiconductor patterning. Its high C:F ratio generates polymer-forming precursors in the plasma that passivate sidewalls and silicon surfaces, providing exceptional SiO2/Si selectivity. Also used as the passivation gas in Bosch DRIE silicon etch cycles.
Technical Specifications
| oxygen | ≤1 ppm |
| moisture | ≤1 ppm |
| appearance | Colorless gas (liquefied under pressure) |
| purity (%) | ≥99.999 (5N semiconductor grade) |
| non-condensable gases | ≤10 ppm |
Applications
- High-selectivity SiO2 contact and via plasma etch
- Bosch DRIE passivation cycle (alternating with SF6)
- SiN and low-k dielectric etch in advanced BEOL
- Hard mask oxide etch for fin and gate patterning
- Extreme selectivity oxide-to-silicon etch (>100:1)
Key Features
- Highest C:F ratio among common fluorocarbons for maximum polymer passivation
- Enables >100:1 oxide-to-silicon selectivity in contact etch processes
- Essential for Bosch DRIE sidewall passivation achieving vertical profiles
- Liquefied delivery simplifies high-flow applications in production etch tools
Send Inquiry
CAS Number
115-25-3
Category
Semiconductor Etching ChemicalsAvailability
In StockSample
Dispatched within 5 days
More in Semiconductor Etching Chemicals
Acetone Semiconductor Grade (Photoresist Removal)
67-64-1
Aluminum Chloride ALD Precursor (AlCl3)
7446-70-0
Ammonia Semiconductor Grade (NH3 Nitride CVD)
7664-41-7
Ammonium Fluoride Semiconductor Grade (NH4F 40%)
12125-01-8
Ammonium Hydroxide Semiconductor Grade (NH4OH SC-1)
1336-21-6
Argon Sputtering Gas (Ar Ultra-Pure)
7440-37-1
Bottom Anti-Reflective Coating (BARC)
Buffered Oxide Etch (BOE) NH4F/HF
7664-39-3