Automatic design rule adaptation of leaf cell layouts

The automatic adaptation of mask layouts to new design rules is considered. A new concept is presented that is based on geometric operations and mask compaction. The geometric operation MELT is discussed in detail; the other operations OR, AND, ANDNOT, OVERSIZE and UNDERSIZE are derived from it. The mask compaction consists mainly of a design rule analysis phase and the execution of a longest path algorithm. Contrary to symbolic compaction the mask compaction is based on polygon edges rather than symbols. With the example of the buried contact it is shown that even relatively complex design rule requirements may be met. Tests with several mask layouts sometimes led to overconstrained conditions. These conditions are located with the aid of a longest path algorithm that has not been applied to compaction programs up to now. Furthermore the inconsistent constraint cycles are broken by a fast jog generation algorithm.