Sub-resolution assist feature generating method, and mask manufacturing method including the generating method

A sub-resolution assist feature generating method comprising:

• segmenting a full shot layout into a plurality of patches;
• performing inverse lithography technology (ILT) on a main feature of at least one of the plurality of patches to generate an ILT image;
• generating a point cloud map including a plurality of points for the main feature;
• symmetrizing the point cloud map based on the ILT image;
• serializing the symmetrized point cloud map;
• extracting a seed for generating a sub-resolution assist feature (SRAF), based on the serialized point cloud map;
• and
• generating the SRAF based on the seed.

A mask manufacturing method comprising:

• performing inverse lithography technology (ILT) on a main feature to generate an ILT image;
• generating a point cloud map including a plurality of points for the main feature;
• symmetrizing the point cloud map based on the ILT image;
• serializing the symmetrized point cloud map;
• extracting a seed for generating a sub-resolution assist feature (SRAF), based on the serialized point cloud map;
• generating the SRAF based on the seed;
• performing mask rule check (MRC) on the SRAF;
• determining whether there is a defect on the SRAF in the performing of the MRC;
• transferring a layout image including the main feature and the SRAF as mask tape-out (MTO) design data when there is no defect;
• preparing mask data based on the MTO design data;
• and
• exposing a mask substrate based on the mask data.