
495Lithography in the Deep Ultraviolet and Extreme Ultraviolet
Chapter 17
However, the damage morphology is rather similar to the nanosecond case as depicted in
Figure 17.23, indicating surface structures with depths of ~60nm. According to Khorsand
et al. (2010), compaction of the multilayer mirror due to intermixing of molybdenum
and silicon is involved in the damaging process.
17.3.3 Damage Testing of Other EUV Optical Materials
e LPP source with the EUV Schwarzschild objective could also be employed to per-
form rst nanosecond damage experiments on other optical materials relevant for future
2
Damage
threshold
10
–50
0
50