SEM IMAGE MODELING USING THE NEW MONTE CARLO MODEL MCSEM

We present the Monte Carlo simulation program MCSEM, developed at the Physikalisch-Technische Bundesanstalt (PTB), Germany, for the simulation of Scanning Electron Microscopy (SEM) image formation at arbitrary specimen structures (e.g. layout structures of wafers or photomasks). The program simulates the different stages of the SEM image formation process: the probe forming, the probe-sample interaction and the detection process. A modular program structure is used for an easy adaptation of the program to new simulation tasks. Arbitrarily shaped 3D structured specimen models can be applied and different electron probe shapes are modeled. Various physical models for electron scattering in solid state material are included. Secondary electron (SE) detection modeling is based on SE raytracing, detectors for backscattered electrons (BSE) and transmitted electrons (TE) are also available. An electromagnetic field solver is used to simulate charging of the specimen and the transport of the SE within the electromagnetic field. Some examples of simulation results are presented together with comparisons with experimental results.