Generation of standard cell library components with increased signal routing resources
Generating cells with increased signal routing resources. In an embodiment, power and ground buses in a metal layer of a source cell are identified and removed. Any vias terminating on the removed buses may also be removed. Additional via and connections are added to other desired layers to provide connectivity to the nodes disconnected due to the earlier removal. According to an aspect of the present invention, such connections are added during a chip design phase (i.e., when the cell instances are incorporated into an integrated circuit, sought to be designed).
1. A method of designing an integrated circuit, the method comprising:
examining, using a computer, a first cell description of a source cell to identify a power bus, the power bus having at least two or more metal layers and wherein the power bus is connected to at least one node of the source cell, wherein the cell description of the source cell represents a physical layout of the source cell;
forming a second cell description of the source cell from the first cell description of the source cell by removing a first metal layer from the at least two or more metal layers using a computer; and
connecting the power bus in the second cell description to the at least one node using any metal layer from the at least two or more metal layers except the first metal layer when the second cell description of the source is incorporated in the integrated circuit using a computer.
2. The method of claim 1 , wherein the forming also comprises removing at least one or more vias connecting the at least one node to the power bus.
3. The method of claim 1 , wherein the first cell description is contained in a first library, the method further comprising:
receiving the first cell description from the first library; and
storing the second cell description in a second library.
4. The method of claim 1 , wherein the second cell description is used in designing the integrated circuit having a more dense routing requirements compared to another integrated circuit designed using the first library.
5. The method of claim 1 , wherein the power bus is held at a DC voltage.
6. The method of claim 1 , wherein the power bus is held at ground.
7. A computer readable non-transitory medium storing one or more sequences of instructions causing a system to enable design of an integrated circuit, wherein execution of the one or more sequences of instructions by one or more processors contained in the system causes the system to perform the actions of:
examining a first cell description of a source cell to identify a power bus, the power bus having at least two or more metal layers and wherein the power bus is connected to at least one node of the source cell, wherein the cell description of the source cell represents a physical layout of the source cell;
forming a second cell description of the source cell from the first cell description of the source cell by removing a first metal layer from the at least two or more metal layers; and
connecting the power bus in the second cell description to the at least one node using any metal layer from the at least two or more metal layers except the first metal layer when the second cell description of the source is incorporated in the integrated circuit.
8. The computer readable non-transitory medium of claim 7 , wherein the forming also comprises removing at least one or more vias connecting the at least one node to the power bus.
9. The computer readable non-transitory medium of claim 7 , wherein the first cell description is contained in a first library, the computer readable medium further comprising:
receiving the first cell description from the first library; and
storing the second cell description in a second library.
10. The computer readable non-transitory medium of claim 7 , wherein the second cell description is used in designing the integrated circuit having a more dense routing requirements compared to another integrated circuit designed using the first library.
11. The computer readable non-transitory medium of claim 7 , wherein the power bus is held at a DC voltage.
12. The computer readable non-transitory medium of claim 7 , wherein the power bus is held at ground.