Multi-layer channel router with new style of over-the-cell routing

This paper discusses a new style of over-the-cell routing, where a new cell structure is introduced. Terminals are located around the horizontal center line in the cell. We regard the region between the central terminals in the upper cell row and ones in the lower cell row as an expanded channel. A new channel router handles that region in a lump where connections to terminals are perfectly achieved by avoiding obstacles in cells. Furthermore, the router shortens the length of polysilicon wires so as to achieve the high-performance circuits. Experimental results show that the router achieves a goal of the size reduction which is predicted according to the theoretical estimation, and that the length of polysilicon wires is dramatically shortened.