Merging sub-resolution assist features of a photolithographic mask

Software for merging a plurality of sub-resolution assist features, the software embodied in a medium and operable to:

• receive a mask pattern for a photolithographic mask, the mask pattern comprising a plurality of sub-resolution assist features;
• select a first sub-resolution assist feature to merge with a second sub-resolution assist feature;
• establish a merge bar width of a merge bar for merging the first sub-resolution assist feature and the second sub-resolution assist feature;
• determine a distance in a predetermined direction between the first sub-resolution assist feature and the second sub-resolution assist feature;
• identify a merging technique in accordance with the distance and the merge bar width;
• and
• merge the first sub-resolution assist feature and the second sub-resolution assist feature according to the identified merging technique.

A system for merging a plurality of sub-resolution assist features, comprising:

• means for receiving a mask pattern for a photolithographic mask, the mask pattern comprising a plurality of sub-resolution assist features;
• means for selecting a first sub-resolution assist feature to merge with a second sub-resolution assist feature;
• means for establishing a merge bar width of a merge bar for merging the first sub-resolution assist feature and the second sub-resolution assist feature;
• means for determining a distance in a predetermined direction between the first sub-resolution assist feature and the second sub-resolution assist feature;
• means for identifying a merging technique in accordance with the distance and the merge bar width;
• and
• means for merging the first sub-resolution assist feature and the second sub-resolution assist feature according to the identified merging technique.

A method for merging a plurality of sub-resolution assist features, comprising:

• receiving a mask pattern for a photolithographic mask, the mask pattern comprising a plurality of sub-resolution assist features;
• selecting a first sub-resolution assist feature to merge with a second sub-resolution assist feature;
• establishing a merge bar width of a merge bar for merging the first sub-resolution assist feature and the second sub-resolution assist feature, the merge bar width being greater than a minimum spacing value and less than a minimum printability value;
• determining a distance in a predetermined direction between the first sub-resolution assist feature and the second sub-resolution assist feature;
• identifying a merging technique in accordance with the distance and the merge bar width by establishing from the distance where there is:
• a separation in the predetermined direction between the first sub-resolution assist feature and the second sub-resolution assist feature, the separation less than the merge bar width;
• a separation in the predetermined direction between the first sub-resolution assist feature and the second sub-resolution assist feature, the separation greater than the merge bar width;
• an overlap in the predetermined direction between the first sub-resolution assist feature and the second sub-resolution assist feature, the overlap less than the merge bar width;
• or
• an overlap in the predetermined direction between the first sub-resolution assist feature and the second sub-resolution assist feature, the overlap greater than the merge bar width;
• and
• merging the first sub-resolution assist feature and the second sub-resolution assist feature according to the identified merging technique by performing at least one of the following:
• if there is a separation in the predetermined direction between the first sub-resolution assist feature and the second sub-resolution assist feature, the separation less than the merge bar width, inserting the merge bar to merge the first sub-resolution assist feature and the second sub-resolution assist feature;
• if there is a separation in the predetermined direction between the first sub-resolution assist feature and the second sub-resolution assist feature, the separation greater than the merge bar width:
• inserting the merge bar within the separation;
• and
• extending at least one of the first sub-resolution assist feature and the second sub-resolution assist feature to merge the first sub-resolution assist feature and the second sub-resolution assist feature;
• if there is an overlap in the predetermined direction between the first sub-resolution assist feature and the second sub-resolution assist feature, the overlap less than the merge bar width, inserting the merge bar to merge the first sub-resolution assist feature and the second sub-resolution assist feature;
• and
• if there is an overlap in the predetermined direction between the first sub-resolution assist feature and the second sub-resolution assist feature, the overlap greater than the merge bar width:
• shortening at least one of the first sub-resolution assist feature and the second sub-resolution assist feature;
• and
• inserting the merge bar to merge the first sub-resolution assist feature and the second sub-resolution assist feature.

A method for merging a plurality of sub-resolution assist features, comprising:

• receiving a mask pattern for a photolithographic mask, the mask pattern comprising a plurality of sub-resolution assist features of one or more priorities;
• and
• repeating the following for each priority of the one or more priorities:
• identifying a current set of current sub-resolution assist features to be merged, the current set comprising sub-resolution assist features of a current priority;
• merging at least two current sub-resolution assist features according to a merge bar width and a current distance between the at least two current sub-resolution assist features;
• updating the current set to yield a next set of next sub-resolution assist features to be merged, the next set comprising at least one sub-resolution assist feature of the current priority and at least one sub-resolution assist feature of a previous priority;
• merging at least two next sub-resolution assist features according to the merge bar width and a next distance between the at least two next sub-resolution assist features;
• and
• setting a next priority as the current priority.

Software for merging a plurality of sub-resolution assist features, the software embodied in a medium and operable to:

• receive a mask pattern for a photolithographic mask, the mask pattern comprising a plurality of sub-resolution assist features of one or more priorities;
• and
• repeat the following for each priority of the one or more priorities:
• identify a current set of current sub-resolution assist features to be merged, the current set comprising sub-resolution assist features of a current priority;
• merge at least two current sub-resolution assist features according to a merge bar width and a current distance between the at least two current sub-resolution assist features;
• update the current set to yield a next set of next sub-resolution assist features to be merged, the next set comprising at least one sub-resolution assist feature of the current priority and at least one sub-resolution assist feature of a previous priority;
• merge at least two next sub-resolution assist features according to the merge bar width and a next distance between the at least two next sub-resolution assist features;
• and
• set a next priority as the current priority.

A system for merging a plurality of sub-resolution assist features, comprising:

• means for receiving a mask pattern for a photolithographic mask, the mask pattern comprising a plurality of sub-resolution assist features of one or more priorities;
• and
• means for repeating the following for each priority of the one or more priorities:
• identifying a current set of current sub-resolution assist features to be merged, the current set comprising sub-resolution assist features of a current priority;
• merging at least two current sub-resolution assist features according to a merge bar width and a current distance between the at least two current sub-resolution assist features;
• updating the current set to yield a next set of next sub-resolution assist features to be merged, the next set comprising at least one sub-resolution assist feature of the current priority and at least one sub-resolution assist feature of a previous priority;
• merging at least two next sub-resolution assist features according to the merge bar width and a next distance between the at least two next sub-resolution assist features;
• and
• setting a next priority as the current priority.

A method for merging a plurality of sub-resolution assist features, comprising:

• receiving a mask pattern for a photolithographic mask, the mask pattern comprising a plurality of sub-resolution assist features of one or more priorities;
• and
• repeating the following for each priority of the one or more priorities:
• identifying a current set of current sub-resolution assist features to be merged, the current set comprising sub-resolution assist features of a current priority;
• merging at least two current sub-resolution assist features according to a merge bar width and a current distance between the at least two current sub-resolution assist features, a current sub-resolution assist feature having an axis, the current distance further comprising a distance measured in a direction substantially parallel to the axis;
• updating the current set to yield a next set of next sub-resolution assist features to be merged, the next set comprising at least one sub-resolution assist feature of the current priority and at least one sub-resolution assist feature of a previous priority;
• merging at least two next sub-resolution assist features according to the merge bar width and a next distance between the at least two next sub-resolution assist features by:
• identifying a merging technique in accordance with the merge bar width and the current distance;
• and
• merging the at least two distance sub-resolution assist features according to the identified merging technique;
• and
• setting a next priority as the current priority.