Proposal of an extended loading effect correction for EBM-8000

To enhance global CDU attained by our EB mask writer EBM-8000, we examined extending the loading effect correction (LEC) function to treat plural of loading effects, for instance, develop and etch loading. Here, we propose a LEC dose composition method, assuming uniquely-defined relation between amount of dose modulation and resultant CD change. Sets of LEC dose maps (pairs of base dose maps and proximity backscattering ratio maps) are converted to sets of CD change maps which are summarized to create a set of dose maps used for writing. This paper describes the correction procedure and possible applications of the method.