Buffer insertion to remove hold violations at multiple process corners

Abstract

Buffer insertion to remove hold violations at multiple process corners is addressed for the first time. The problem is formulated as integer linear programming (ILP); it is combined with circuit partitioning heuristic so that larger circuits can also be handled. A heuristic buffer insertion algorithm is then proposed and compared to ILP, which demonstrates only a slight increase of the number of buffers (2.4% on average). Two additional intuitive methods are implemented to demonstrate why new heuristic algorithm is needed: conventional buffer insertion at each process corner one by one and conventional buffer insertion at all process corners simultaneously followed by combining insertion results.