An Over-The-Cell Router

A program that produces single-layer planar routing over the cells for I2L and LST2L logic arrays is described. This router has been integrated into a layout system which was previously restricted to the layout of standard cell LSI chips. When used in conjunction with a channel router, the complete routing is produced automatically. This paper defines the over-the-cell routing problem, describes the algorithms for its solution, and presents typical routing results.