In Shallow Trench Isolation and Nitride Spacer Etch Back process steps, high temperature Phosphoric Acid is used to remove Silicon Nitride. In today’s industry, with shrinking device topography, loss of Silicon Oxide is unaffordable. In order to increase etch selectivity of Nitride over Oxide and control the rate of Nitride etch, a specific range of hydrated Silica in the Phosphoric Acid solution must be closely maintained.
Quali-Surf QSF-500 is designed to accurately measure ppm levels of Silica in hot Phosphoric Acid solutions. This online system provides fast results and interfaces seamlessly with Nitride Wet Etch stations. With self-calibration and auto-verification capabilities, absolute accuracy of the analysis is ensured, down to the 10ppm range. QSF-500 is the only tool on the market offering automatic, continuous measurement of Silica in Hot Phosphoric Nitride Etchant.
- Fast and accurate results in 0-100ppm range
- Temperature controlled analysis
- Patent pending
- Automatic validation of results
- Seamless Wet Station interface via 4-20mA, RS-232, or TCP/IP protocols
- Feedback signal for closed-loop control
- Small footprint
- Phosphoric acid analysis optional
- Low CoO
- Phosphoric Acid: 150-180°C
- Silicon content: 0-100ppm
- Accuracy: ±5ppm
- Analysis time: <7 minutes/measurement