VITAL: fully automatic placement strategies for very large semicustom designs

VITAL is a program for generating fully automatic layouts of any design that combines standard cells and macrocells. Among the program's unique standard cell placement algorithms are simultaneous X/Y placement and channel-density improvement algorithms and an innovative algorithm for reducing chip width by using over-the-cell crossover. Iterative cell placement improvement strategies, such as cell row balancing and cell migration, which result in over 10% area reduction, make VITAL an extremely effective layout tool. The frequent interaction of the placement algorithms with the routing function results in denser chip layouts, as much as 25% smaller than those achieved with commercial tools. The steps of the standard cell-placement procedure are described in detail. >