Heraeus Quarzglas – Carl Zeiss SMT Supply Chain Partner
Suprasil 501: Extremely Radiation Resistant Fused Silica for Microlithography
In microlithography tiny structures (down to 45 nm) of highly complex integrated circuits are projected on to silicon wafers from different photomasks. This is accomplished by lens systems made from bubble free and optically extremely homogenous fused silica. The storage density and performance of microchips doubles every two to three years. This necessitates new gener- ations of lens systems being able to image the constantly shrinking structures. The synthetic fused silica used in these optics has to follow this development as well.
With Suprasil 501 Dr Stephan Thomas and his team from Heraeus Quarzglas have developed an extremely radiation resistant generation of fused silica. Fused silica during its lifetime as a lens material in stepper-optics, has to survive over 200 billion laser pulses undamaged and may show only the slightest deviation in the index of refraction or in transmission losses.
This requirement is fulfilled by Suprasil 501. This is achieved by hydrogen molecules existing in the glass which may cure laser-induced defects. The defects would otherwise cause a degradation of the outstanding optical properties of the material.