APPLICATION: THIN FILM OPTICAL CHARACTERIZATION
Thin films can be characterized from different aspects. The below listed applications can provide simple and clear information about the wide range of thin film classification.
- Optical, electronic and energy applications: solar cell materials, thermochromic and electrochromic materials, nanocrystalline films. Thin films and doped layers. Study of temperature-dependent optical phase transitions.
- Bio-ellipsometry: biosensor based on measuring the phase shift and Mueller matrix of monomolecular coatings. Anisotropic materials inspired by nature. Total internal reflection ellipsometry. Study of solid-liquid interfaces.
- Real-time ellipsometry: measurement in situ during vacuum chamber deposition cycles.
- Graphene and novel 2D and 3D materials. Characterization of plasmonic response of patterned surfaces. Specular, and oblique angle scatterometry.
- High accuracy determination of optical functions (refractive index, absorption) versus wavelength.
TECHNOLOGY: SPECTROSCOPIC ELLIPSOMETRY
In the semiconductor industry, there is continuous demand for higher performance and denser integrated circuits. These requirements push the advancement of technology which requires solving of manufacturing challenges. A key to success is to understand the chemical, mechanical and physical properties of wide range of materials used in a typical integrated circuit.
The µSE tool is designed to measure thin film thickness and optical properties inside a <50µm test pad on semiconductor product wafers. The applied measurement technique for obtaining these parameters in a high accuracy and repeatable way is spectroscopic ellipsometry. The μSE tool uses optimized spectroscopic ellipsometer (SE) arms and optics for the measurement inside small boxes of patterned Si wafers.
Ellipsometry measures the phase of the reflected light from the sample, therefore it is relatively insensitive for intensity fluctuations. The raw measurement data represent the complex information from the layer stack which then need to be modeled optically. The measurement results are obtained through numerical regression process of the model data to the raw measurement spectrum.
TYPICAL SE REGRESSIONS:
- Non-destructive optical technique, based on measurement of the change of the polarisation state of light after reflection at non normal incidence on the surface to study.
- It is a higly sensitive even for layer thickness below 5 nm
- Extremely versatile technique: it gives acccess to numerous parameters which characterize multilayer structures (eg. layer thickness, refractive index, absorption, porosity).
- Spectroscopic Ellipsometry with rotating compensator
- Generalized Ellipsometry for anisotropic samples
- Mueller matrix 11 coefficients
- Jones matrix
- Porosimetry: Measurements of pore size distribution and porosity in thin films
- In situ measurement mode for real time control during deposition or etch process
- Near-infrared spectral extension
- Atmospheric thin film Porosimetry
- Liquid cell cooling and heating stages
- Visualization camera
- Spectroscopic reflectometer
- Liquid cell, cooling and heating stages
Find out more on the Semilab website