Methodology of flare modeling and compensation in EUVL

Flare in EUV mirror optics has been reported to be very high and long range effect due to its character which is inversely proportional to the 4th order of wavelength. The high level of flare will generate CD (Critical Dimension) variation problem in the area where the gradient of aerial pattern density is large while the long range influencing character would confront an issue of computational challenge either for OPC (Optical Proximity Correction) modeling or for any other practical ways to accommodate such a long range effect. There also exists another substantial challenge of measuring and characterizing such a long range flare accurately enough so that the characterized flare can successfully be used for the compensation in the standard OPC flow.