The best quality control can be achieved by inline process monitoring to check every wafer in the manufacturing process. However, in some cases the short cycle time (usually less than 1 second) does not allow to realize detailed analysis of the wafer, which may include full wafer mapping and techniques requires mechanical contacts.
The measurement tools were designed to include non-destructive techniques and favor non-contact methods where possible.
The applications include the followings:
Laser ellipsometry measures a change in polarization as light reflects or transmits from a material structure. The polarization change is represented as an amplitude ratio, Ψ, and the phase difference, Δ. The measured response depends on optical properties and thickness of individual materials. Thus, ellipsometry is primarily used to determine film thickness and optical constants. However, it is also applied to characterize roughness and surface morphology by using scatter light measurement method.
Applications: tunnel oxide (thin SiO2 on Si), and poly-Si on SiO2/Si wafer structures monitoring
Laser Ellipsometer For Silicon Solar Cells
Compact, innovative equipment designed to measure the Thickness and Optical constants of Anti Reflective Coatings deposited on textured Silicon (mono-Si & multi-Si) substrates. Optimized angle of incidence (12-90°) can be easily achieved in order to obtain a maximum signal for thin films deposited on multicrystalline structured wafers. The pyramidal structure can be oriented to obtain correct measurements while sample is maintained securely in place.
Features and System specifications: