Scanner performance is influenced by the quality of its illumination, mechanical and optical elements and the impact of
these factors on the printed wafer. Isolation of the aggregated scanner errors from other sources of error on the printed wafer
is a challenging task since the total error budget of the lithography process consists of many dynamic sources, such as wafer
planarity and film stack properties.
The mask is conceptually part of the scanner optics and integral to the imaging process. Therefore the mask error
contribution to the overall error becomes relevant for any advanced lithography process.
Discrete mask measurement techniques are currently used to create across mask CDU maps. By subtracting these maps from
their final wafer measurement CDU map counterparts, it is possible to assess within certain limitations the real scanner
induced printed errors. The current discrete measurement methods are time consuming and some overlook errors other than
linewidth variations, such as transmission and phase variations, all of which influence the final printed CD variability.
In this paper we present a methodology, which leverages Applied Materials Aera2tmmask inspection tool, based on a socalled
IntenCD aerial imaging produces maps by scanning the mask at high speed, offer full mask coverage and accurate
assessment of all mask induced errors simultaneously, making it ideal for mask CDU characterization and scanner