Atomic hydrogen (H) is critical for passivation, surface chemistry, and defect control in plasma-based deposition and cleaning. However, its low steady-state density (≤1e14 cm^-3), rapid recombination (µs–ms), and strong surface reactivity make direct measurement extremely challenging. High-accuracy techniques such as LIF or mass spectrometry are expensive, maintenance-intensive, and difficult to integrate into production environments. A non-invasive, inline, and scientifically validated diagnostic is essential to stabilise recipes, improve yield, and reduce ramp time.

Inteleg® AI-OES delivers real-time optical emission actinometry for H2/Ar plasmas. The system captures the emission spectrum and computes the intensity ratio in real time. Using CSensor, it applies a validated equation incorporating branching fractions and electron-impact excitation rate coefficients, providing a quantitative, SI-consistent estimate of relative hydrogen density. A flow-based variant (with MFC feedback) outputs nH directly for on-tool monitoring. Full details, including recommended spectral line pairs and calculation workflow, are provided in the dedicated application note available at:

https://inteleg.io/digital-documents/138--app-note-002-oes-actinometry-intelegR-ai-oes-actinometry-for-h2-ar-plasma-diagnostics.html

The method is proven for low-pressure, optically thin plasmas and validated against absolute diagnostics.

• Operational Impact: Detect hydrogen drift within seconds; stabilise refractive index, stress, and passivation in PECVD/PEALD.
• Measurable Performance: Repeatable ratio trendlines for SPC and automated interlocks.
• Ease of Integration: Non-invasive fibre-to-viewport design; CSensor computes ratios and densities in real time; retrofit-ready for OEM and installed base.
• Cost Advantage: A fraction of LIF/CRDS cost; no vacuum taps or invasive probes; minimal maintenance overhead.

• Technique: Optical Emission Spectroscopy (OES) with argon actinometry.
• Temporal Performance: Real-time CSensor evaluation; update rate 1–10 Hz.
• Operating Conditions: 10–100 mTorr; optically thin regime; verify self-absorption at higher pressures.
• Workflow: CSensor formulas for ratio and flow-based nH; SI unit normalisation; trend logging.
• Integration: Fibre-coupled viewport optics; compact spectrometer; API and export options.

Explore products at https://inteleg.io/

Have an application in mind? Contact Nova Fabrica: https://www.novafabrica.biz/contact/contact-us

• Unlike costly LIF/CRDS or QMS, Inteleg® delivers non-invasive, production-ready monitoring using a peer-reviewed, validated method.
• Typical pitfalls of intensity-only OES—temperature sensitivity, optical drift—are mitigated via actinometric normalisation, branching-fraction correction, and SI-consistent workflow.

Optical Emission Spectroscopy — https://www.novafabrica.biz/solutions/optical-emission-spectroscopy