This paper describes a fully automatic standard-cell layoutsynthesis system, CELLERITY. The system is flexible insupporting a wide variety of process technologies and a range oflibrary template styles. The tool is fully automatic and providesseveral options to the user to customize the layout template. Thetool considers performance and yield and generates dense,design-rule correct layouts. Experimental results indicate that thearea of CELLERITY-generated standard cells is competitive withmanually designed cells in a majority of circuits. In block-leveltests of industrial circuits, standard-cell blocks generated usingCELLERITY cells are about equal to the block area produced byusing a manually-designed library. Recently, an embeddedmicrocontroller in a state-of-the-art sub-micron processtechnology was fabricated using CELLERITY-generated standard cells.

A formal methodology is presented for the layout of a single CMOS functional cell and an array of such cells, which addresses height minimization as well as the ustrrd width minimization.Exact layout algorithms are presented which are the fust to minimim width and height for all cells of practical size, and are computationatly feasible for these circuits.We present the results of a comprehensive set of experiments in which we generated layouts for all practicat-sized circuits.We compare our optimat layouts to published designs, most of which are based on nonoptirnat heuristics.We show that not onty do our optimat algorithms yield si~lcant area savings, they also incur little penatty in amputation time.

A general theory for designing minimum-area layouts of static series-parallel CMOS functional cells (also called complex gates) in a standard cell layout style is presented. T. Uehara and W.M. vanCleemput. (1981) originally formulated this as the graph optimization problem of finding the minimum number of dual trails that cover a multigraph model of M of a cell. The present theory provides a formalism for the analysis of series-parallel graphs and identifies the mathematical structures that underlie the layout problem. It also leads to two efficient algorithms for designing minimum area functional cell layouts. The first algorithm, TrailTrace, accepts an ordering of M that is fixed, typically for performance reasons, and produces the minimum area layout for that ordering. Its time complexity is linear in the number of transistors in the cell. The second algorithm, R-TrailTrace, reorders M and produces the best layout area that can be achieved for any reordering that preserves the cell's functionality.>