Lithographic flare measurements of Intel’s microexposure tool optics

Abstract

Measurements of flare as a function of feature size, pitch, and orientation have been made on Intel’s extreme ultraviolet microexposure tool (MET) using a high sensitivity photoresist. The high sensitivity photoresist does not cross-link at the high doses required to measure flare. The predicted value for intrinsic flare for the MET from mid-spatial frequency roughness (MSFR) of mirror surfaces is 3.5%. After addition of the contribution to flare from high order aberrations to that from MSFR, the modeled value is in excellent agreement with the measured flare for the 1μm line of 4%. The measured flare in the horizontal direction is 5% and is higher than the flare in the vertical direction. The point spread function due to scatter has been computed and the modulation transfer function of the system as a function of pitch has also been measured.