VUV-VASE
9Pages

J.A. Woollam Co., Inc. Ellipsometry Solutions

First in the VUV The VUV-VASE® variable angle spectroscopic ellipsometer is the gold standard for optical characterization of lithography thin films. It measures wavelengths from vacuum ultraviolet (VUV) to near infrared (NIR). This provides incredible versatility to characterize numerous materials: semiconductors, dielectrics, polymers, metals, multi-layers and liquids such as immersion fluids. Why a VUV-VASE? Wide Spectral Range The VUV-VASE covers wavelengths from below 140nm to 1700nm. High Accuracy Utilizing our patented AutoRetarder®, the VUV-VASE guarantees accuracy for any sample...

Two Generations The VUV-VASE® was developed in 1999 to meet metrology requirements for 157nm lithography research. The first generation (Gen-I) tool is perfect for new materials research. A second generation (Gen-II) tool was introduced to provide large area mapping of photomasks and wafers. Gen-I Measure samples up to 200mm diameter. Gen-II Translation Options: • 140mm XY • 300mm R-T

Key Features Wavelength Range The VUV-VASE can measure any wavelengths between 140nm and 1700nm, or photon energies between 0.73eV and 9eV. Nitrogen Purge The VUV-VASE is purged continuously with dry nitrogen gas to eliminate the atmospheric absorption of light below 190nm by oxygen and water vapor. Gen-I Sample Load Lock Angle Range The VUV-VASE systems feature automated angle of incidence with wide angular coverage. GEN-I 10°-90° (wavelengths <300nm) 25°-90° (wavelengths >300nm) GEN-II 10°-90° (wavelengths <300nm) 20°-90° (wavelengths >300nm) Automated Sample Alignment Load your samples...

Characterization Wide Range The VUV-VASE measures a very wide photon energy range from 0.73eV to 9eV. This allows study of the electronic transitions in all types of semiconducting and dielectric films. The high energy electronic transitions of group-III Nitrides affect the VUV dielectric functions, as shown to the right. Ultra-thin Films 180 Oscillator Model Transparent Model SiO2 Model Exp Data, 70° Exp Data, 80° The VUV-VASE offers two advantages for ultra thin film characterization: • Short wavelengths are more sensitive to thin layers. • UV absorption differentiates materials. Data...

Advanced Measurements Anisotropy/Mueller-matrix Complex materials and nanostructures often require advanced characterization methods. The VUV-VASE can measure “generalized-SE” data from anisotropic materials and “Mueller-matrix” data from more complex structures. Dielectric functions for hexagonal silicon carbide are anisotropic. In figures to the left, the ordinary and extraordinary properties are both measured. Notice the large differences in the VUV region. Gen-II Sample Loading AutoRetarder® The VUV-VASE accuracy is ensured by our patented AutoRetarder*. The AutoRetarder is a computer...

Lithography thin films were an important motivation for the VUVVASE® development. It has been successfully used to characterize all types of films in this area, including: • Photoresists • Bottom and Top AR Coatings • Photomask Coatings • Hardmasks • Stepper Optical Coatings • Pellicles •CaF2 Optics • And more... Photoresist Measure film thickness and refractive index (n and k) at all lithography lines: 157nm, 193nm, 248nm...

Coatings on Stepper Optics Optical elements used in lithography exposure tools can be enhanced using optical coatings. Coating merit depends on refractive index and thickness. Fluorinated materials are candidates at 157nm, as they remain transparent into the VUV. The index for various fluorides measured with VUV ellipsometry is shown (right). In addition, the VUV-VASE can measure transmitted intensity to ensure the material quality does not introduce light absorption at the exposure wavelength. The VUV is also used to study coating damage from irradiation. Liquid Prism Cell Immersion...

Dimensions Gen-I Weight Floor Space • 8’ (240cm) wide, min. • 6.75’ (200cm) deep (Includes space for operator in front) Ceiling Height Electrical Power Gen-II Weight Floor Space • 9’ (280cm) wide, min. • 6.75’ (200cm) deep (Includes space for operator in front) Ceiling Height Electrical Power