Mask-LMC: lithographic simulation and defect detection from high-resolution mask images

ABSTRACT We report the development of Mask-LMC for defect printability evaluation from sub-200nm wavelength mask inspection images. Both transmitted and reflected images are utilized, and both die-to-die and die-to-database inspection modes are supported. The first step of the process is to recover the patterns on the mask from high resolution T and R images by de-convolving inspection optical effects. This step uses a mask reconstruction model, which is based on rigorous Hopkins-modeling of the inspection optics, and is pr e-determined before the full mask inspection. After mask reconstruction, wafer scanner optics and wafer resist simulati ons are performed on the reconstructed mask, with a wafer lithography model. This step leverages Brion’s indu stry-proven, hardware-accel erated LMC (Lithography Manufacturability Check) technology 1 . Existing litho process models that are in use for Brion’s OPC+ and verification products may be used for this simulation. In the final step, special detectors are used to compare simulation results on the reference and defect dice. We have developed detectors for contact CD, c ontact area, line and space CD, and edge placement errors. The detection resu lt has been validated with AIMS