Patent ID: 8174052

Claim:
A standard cell library comprising: a first power rail extending in a first direction; a second power rail extending in the first direction, the second power rail being spaced apart from the first power rail by a predetermined spacing in a second direction that is perpendicular to the first direction; a third power rail extending in the first direction between the first power rail and the second power rail; at least one first standard cell having a first cell height in the second direction, the first standard cell being arranged between the first power rail and the second power rail and being electrically connected to the third power rail; and at least two second standard cells, each second standard cell having a second cell height in the second direction and arranged between the first power rail and the second power rail, the second standard cells being in contact with each other in the second direction and being in contact with the first standard cell in the first direction; wherein the first standard cell uses a first metal layer for signal routing between impurity regions, wherein the first metal layer comprises a lowest metal layer in the standard cell library and wherein the first and second power rails are formed in the first metal layer; and wherein the third power rail is connected to the first standard cell and the at least two second standard cells and wherein at least a portion of the third power rail is formed in a second metal layer that is above the first metal layer.