TECHNOLOGY

Spectroscopic Reflectometry (SR) and Ellipsometry (SE) are proven technologies for non-destructive and accurate optical characterization of materials. Historically, these techniques have utilized longer wavelengths (190nm – 800nm) to determine thin film thickness and refractive index (n and k). New advanced materials and their successful integration require much greater measurement sensitivity and precision for the film thicknesses, the interfaces formed and the composition.

Metrosol has developed and patented a means to enhance and extend the capabilities of SR with its Short Wavelength Optical Metrology technology, which extends the Vacuum Ultra-Violet (VUV) wavelength region - down to 120 nm. Metrosol is the only company to operate in the VUV region to 120 nm (Figure 1). Proprietary optics, software and hardware enable rapid and robust data collection and analysis at wavelengths which probe more detailed structure and therefore result in exceptional sensitivity to thickness and composition (Figures 2 & 3).

Figure 1. Traditional optical metrology wavelength limits compared
to Metrosol's enhanced spectral range.




Figure 2. Wavelengths <190 nm are required
for composition sensitivity



Figure 3. Thickness and composition sensitivity are greatest
in the VUV region. In the "Thickness Comparison", these wafers
have the same composition but vary in thickness by 12 Å.
In the "Composition Comparison", these wafers have the
same thickness but vary in composition from 0-60% silicate.

The unique capabilities of Metrosol’s short wavelength technology include:

• Exceptional sensitivity for film and interface thickness > 0 Å
• Exceptional sensitivity for composition measurements
• Small and flexible optical metrology module for in-situ capabilities
• High throughput (1-10 seconds/point) with small measurement spot