A CMOS sea-of-gates array with continuous track allocation

A macrocell architecture which is suitable for sea-of-gates (SOG) arrays and improves gate density is described. A layout scheme using a novel structure called column macrocell (CMC) implements every macrocell by stacking BCs (basic cells) along the BC column until enough gates are accumulated. In the CMC structure, the first-level wiring runs along the BC column, and the wiring channel width can be adjusted by 1-2 tracks. Therefore just as many tracks as are necessary in a channel are produced by first-level wiring. The effectiveness of the CMC structure is verified by implementing an SOG chip using LDD (lightly doped drain) PMOS and NMOS transistors with 0.8- mu m physical and 0.55- mu m effective gate length. The features of the CMC structure are compared with those of the RMC (row macrocell) structure.<>