Yieldstar Based Reticle 3d Measurements And Its Application

Yield Star (YS) is an ASML-built scatterometry tool with well-established capability to measure wafer Critical Dimension (CD), Overlay and Focus. In a feasibility study, the application range of YS was extended to measure CD patterns on EUV reticles (absorber CD, height, Side Wall Angle-SWA). The measured data compared well with the available data from CD-SEM and AFM. Further the YS measured data was used to mathematically separate the reticle induced fingerprint from the scanner fingerprint.