Mask Design Method for Un-Patterned Dark Field Defect Inspection System

As the impact of defects on yield has become significant for advanced process technology nodes, it is imperative to shrink the defect inspection dimension. In this work, mask design method for un-patterned dark field defect inspection system is proposed to reduce the haze signals caused by wafer roughness. The mask is designed according to the bidirectional reflectance distribution function. The effect of the mask is verified by the scattering model we have developed based on the tools which NIST provided. The mask is designed to block part of the strong haze signals, which effectively improves the accuracy of defect inspection.