Investigation of stray light characteristic by multiple Gaussian modeling and its OPC application

Stray light is analyzed by scattering range. For the short range, stray light distributes as 1/r4 and comes from aberration. For the mid range and the long range, in the assumption of Gaussian distribution, characteristic scattering length of specific tools is estimated. EOR is proposed which contains information of layer geometry and scattering range characteristic of flare. To minimize CD errors from OPC, flare level and EOR should be considered in the OPC procedure.