Synopsys, Inc.
Method of modeling e-beam photomask manufacturing process using image-based artificial neural networks

Abstract:

An image-based Artificial Neural Networks (ANN) is used for photomask modeling, which can self-construct an internal representation of the photomask manufacturing process, therefore allowing the modeling process to become unfettered by the limitations of existing mathematical/statistical tools, thus greatly reduces/eliminates the effort needed from tedious and costly model-builders. The ANN model requires mask layout data converted into image pixel form. In ANN training phase a first circuit image and its existing SEM image are modeled via multiple layers of convolution and rectification to pick out the salient features of transformed image. In ANN testing phase, a second circuit image and its existing SEM image are compared and verified to have a difference smaller than the predetermined requirement. The satisfactory second circuit image is converted back from pixel form to circuit layout data for photomask writing.