Transistor placement and interconnect algorithms for leaf cell synthesis

Picasso is a prototype leaf cell synthesis system capable of mapping a gate level description into a complete set of layout masks, based on the line of diffusion layout style. This paper describes Picasso´s algorithms for transistor placement and routing of internal nets. The transistor placement algorithm uses a composite metric which applies connectivity and optimal chaining considerations simultaneously. The routing algorithm is capable of routing over transistor chains and makes efficient use of residual routing areas resulting from unequal transistor sizes