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iLab Name: Cleanroom Ellipsometer
iLab Kiosk: BRK Metrology Core
FIC: Shared
Owner: Rich Harlan
Location: Cleanroom - P Bay
Maximum Wafer Size: 6"/150 mm
Overview
General Description
The cleanroom Ellipsometer can measure the thickness and refractive index of thin films on reflective substrates, as well as the optical properties of bare substrates.
Specifications
- The stage can handle up to a 6 inch wafer diameter
- Light source: HeNe laser, 632.8 nm, 1 mW output.
- Incidence angles: 70° (default), 50°, 30°.
- Maximum sample thickness: 1/2 inch.
- Maximum sample diameter: 5 inch.
- Film thickness range: 0-60,000 Angstroms.
- Accuracy: ±3 Angstroms (manufacturer claimed over most of measurement range)
- Repeatability: ±1 Angstrom (manufacturer claimed over most of measurement range)
- Spot size is approximately 1mm by 3mm
- Your substrate must be polished and must not rough to defract the laser
Technology Overview
Ellipsometry measures the thickness of an optically transparent film based on a change in polarization of an incident laser. This change is compared to a model, and values for thickness and refractive index are calculated. The values PSI (psi, Ψ) and DEL (delta, Δ).
The software uses the following abbreviations:
- d: Thickness of film being measured
- Nf: Real value of refractive index for film being measured
- Kf: Imaginary value of refractive index for film being measured
- ω (OMEGA): Thickness period; used for determination of thick film thickness
- Ns: Real value of refractive index for substrate
- Ks: Imaginary value of refractive index for substrate
- Φ (PHI): Angle of incidence
- ψ (PSI): Amplitude ratio as determined by measurement
- Δ (DELTA): Phase difference as determined by measurement
- λ (LAMBDA): Wavelength of incident light; fixed at 632.8 nm for HeNe laser
Sample Requirements and Preparation
Backside must be free of contaminants that may transfer to the stage. The area of measurement should be clean to be measured properly.
Standard Operating Procedure
Questions & Troubleshooting
Process Library
References
Manufacturer brocheurs, specifications, papers with relevant info on process, and presentations covering the technology. Confluence lacks a native reference feature, so these are added as links.