MODIFICATION OF MASK LAYOUT DATA TO IMPROVE WRITEABILITY OF OPC

A data storage medium contains mask layout data for use in writing a mask includes a first mask data portion which corresponds to a feature having an interior corner. The first mask data portion corresponding to the interior corner includes a multi-level or stepped inner serif in the interior corner which provides for improved writeability of OPC independent of process push or bias. Alternatively, the data storage medium contains mask layout data which includes a second mask data portion. The second mask data portion corresponds to a feature having an exterior corner and includes a multi-level or stepped outer serif on the exterior corner. The stepped outer serif also provides for improved writeability of OPC independent of process push or bias.