The allowable wafer Critical Dimension Uniformity (CDU) budget of the 2x node poses stringent requirements on mask
induced errors at wafer level. The total CDU budget of 2 nm which is partially consumed by across wafer and field process
and imaging variations, leaves little room for additional mask errors to still comply to the overall CDU budget. The trend of
higher mask error enhancement factor (MEEF) for advanced technology nodes aggravates this situation further.
Traditionally, the assessment of these variations is based on separate critical dimension and phase/transmission
measurements. Metrology measurement tools are typically based on different techniques to independently measure each
source of non-uniformity and produce the required uniformity maps. Each technique concentrates on a single physical
property (e.g., line-width, phase, transmission, etc.) and requires special calibration for the required accuracy, precision and
its transformation from mask to the wafer nanometer domain. An alternative to all these separate measurements is proposed
by using the IntenCDTM application based on the aerial image of the mask. This alternative approach provides a map of
mask-induced, printed CD variations across the photomask.
In this paper, a study is presented to estimate mask-induced printed CDU at wafer level from the aerial image and results are
compared to mask- and phase-CD measurements. The work shows that a single aerial IntenCD map can replace the two sets
of data based on mask-CD and mask-phase measurements and allows for prediction of the mask contribution to overall