40th high-resolution ELIAS echelle spectrometer for spectral characterization of laser lines for excimer lithography installed
LTB Lasertechnik Berlin GmbH, the world’s only supplier of Echelle spectrometers with a resolution of < 0.1 pm has delivered its 40th ELIAS Echelle Spectrometer. Customers come from Germany, the USA and Japan.
The spectrometer’s main area of application is in excimer laser lithography. While the ELIAS-Standard is used for the measuring of KrF lasers at 248 nm and ArF lasers at 193 nm, the ELIAS-VUV is applied for F2 lasers at 157 nm.
Because of their chromatic aberrations, the refraction objectives in the wafer steppers require an extremely high spectral purity of the radiation sources. A laser manufacturer who can offer radiation sources with the lowest spectral width can realize a strong competitive advantage.
In connection with this, the highly resolving measurement of laser lines with an intensity dynamic range of up to four orders is of the utmost importance. Deviations in the femtometer range (10-15 fm) in the half-width, as well as in the wings of the lines, must be evaluated precisely and repeatable.
The spectrometer can also be applied for the measuring of extreme narrow-band laser lines in the VIS and NIR range.