Spectroscopic Ellipsometry for Thin Film Metrology Guide
What spectroscopic ellipsometry measures
Spectroscopic ellipsometry measures how polarized light reflects from a sample. The two primary outputs are Psi (Ψ) and Delta (Δ), which encode information about film thickness and optical constants.
With a suitable model, those signals become actionable thickness and material parameters for process control.
Reading the outputs
Use the table below as a quick reference when reviewing ellipsometry results with your application engineer.
| Output | Symbol | What it means for your process |
|---|---|---|
| Amplitude ratio | Psi (Ψ) | Sensitive to film stack reflectance balance |
| Phase difference | Delta (Δ) | Highly sensitive to thin-film thickness change |
| Modeled thickness | d | Process KPI after optical model fit |
When to talk to Techcess
If you are qualifying a new stack or comparing offline vs inline strategies, our Plano team can help map measurement goals to the right tools and US support coverage.