Proceedings Article | 17 October 2008
Proc. SPIE. 7122, Photomask Technology 2008
KEYWORDS: Lithography, Contamination, Quartz, Air contamination, Pellicles, Transmittance, Photomasks, Critical dimension metrology, Semiconducting wafers, 193nm lithography
We have investigated the factors having influence on the lithographic fidelity variation in 193nm masks. Significant
researches have been studied that haze contamination, resulting from the absorption of chemical residual ions and mask
container out-gassing in mask fabrication, is one of the major component to reduce the optimized lithography condition
such as Best Focus, Depth of Focus and Exposure latitude of individual feature. And also environment being containing
humidity, ambient AMC (airborne molecular contamination) react with high exposure energy to form crystal growth of
ionic molecular complex such as ammonium sulfate causing abnormal printability. Moreover, optical issue of organic
pellicle membrane is thoroughly considered that perfluoro polymer degradation induced by high photon energy affect the
transmittance intensity. Consequently, these photophysical alterations bring about the lithographic variation and cause
considerable defects in wafer printing.
In this paper, we tried to verify the influence grade inducing the lithographic variation among the latent contamination
factors consisting of mask back-side quartz contamination, the growth of exposure energy based haze phenomena, thin
organic pellicle membrane degradation and modified character of MoSiN surface. Metrological inspection and
photochemical reaction evaluations were conducted with several equipments including AIMS, Scatterometer, XPS, SIMS,
FT-IR, UV, ArF acceleration laser to demonstrate the proposal mechanism of correlation between lithographic variation
and latent contamination factors. The optical issues and lifetime of ArF PSM were simulated with the evaluation of
effects of pellicle degradation and surface modification.
