M31’s 6.5-Track Library reduces 8~13% area and 13~26% power consumption in 22/28nm node. In general, the common Standard Cell libraries include 7-Track, 9-Track, and 12-Track libraries. A “Track” is used as a unit to define the height of the standard cells in physical layout. For example, 12-Track means 12 Metal-1 lines are available as the routing space within the cell. Therefore, 12-track cells are taller than 9-track cells. 9-Track are taller than 7-Track.