Proximity Effect Correction Parameters for Patterning of EUV Reticles with Gaussian Electron Beam Lithography

Proximity Effect Correction parameters for Electron Beam Lithography are of critical importance for Critical Dimension uniformity and pattern fidelity in the manufacture of Extreme Ultraviolet Lithography reticles(1). The values of these parameters are well known for simple substrates, such as silicon wafers, but complex substrates such as EUV blanks, composed of several layers of materials (quartz, molybdenum, silicon and ruthenium) present a challenge(2,3). The authors present a single exposure method for determining the PEC parameters for arbitrary substrates, demonstrated on silicon wafers and EUV reticles using a VB300 Gaussian EBL writer and patterns conducive to CDSEM metrology. The authors demonstrate the ability to utilize the parameters determined using this method to attain less than 3nm three-sigma CD uniformity across the pattern. The results of this empirical approach are compared to the results of Monte Carlo simulation to determine which layers in the EUV stack have the most impact on the optimal PEC parameters obtained.