Investigations of the dynamic absorptance behaviour of hybrid multilayers at 193 nm
SPIE Boulder Damage
1.-3. Oktober
Boulder
2002
Type: Konferenzbeitrag
Abstract
In previous years different multilayer systems were investigated with respect to their optical In previous years different multilayer systems were investigated with respect to their optical performance at the wavelength 193 nm of the ArF excimer laser. For most applications in this spectral range, fluoride coatings have been qualified and are widely established. Even though the applicability of oxide coatings is strongly restricted by the significant intrinsic absorptance of the Al/sub 2/O/sub 3/ component, these materials are utilized for special technology fields. In contrast to the dielectric deposition materials, the potentiality of protected and enhanced metal layer systems has not been investigated in detail as a basis for high reflectivity mirrors at the wavelength of 193 nm. The major advantage of metal layers is their relatively high reflectivity which can be achieved at low film thickness. Thus metal layers can be employed as a substitution of the first HL-pairs in a high reflecting dielectric stack, and the number of layers can be drastically reduced. Furthermore, the upper residual fluoride stack shields the metal coating from the E-field, improving the power handling capability of the metal layer. The present investigations are focused on the determination of the absorptance in dependence on the different number of fluoride HL-pairs in metal/dielectric layer systems