Stability-dependent spare cell insertion

A computer system comprising:

• one or more processors which process program instructions;
• a memory device connected to said one or more processors;
• and
• program instructions residing in said memory device for placing spare cells in an integrated circuit design, by receiving a description of the integrated circuit design which includes at least one logic cone in a layout and a stability value associated with the logic cone, assigning a desired spare cell utilization rate to the logic cone based on the stability value, calculating an actual spare cell utilization rate for a bounding box of the logic cone, determining that the actual spare cell utilization rate is less than the desired spare cell utilization rate, computing additional area required in the bounding box for attaining the desired spare cell utilization rate, and inserting, in the description of the integrated circuit design, one or more spare cells within the bounding box to completely fill the additional area.

A method of integrated circuit design comprising:

• placement directed synthesis including cone-based, stability-dependent spare cell insertion;
• early mode padding after completion of said placement directed synthesis;
• and
• design routing after completion of said early mode padding, wherein said cone-based, stability-dependent spare cell insertion includes receiving a description of an integrated circuit design which includes at least one logic cone in a layout and a stability value associated with the logic cone, assigning a desired spare cell utilization rate to the logic cone based on the stability value, calculating an actual spare cell utilization rate for a bounding box of the logic cone, determining that the actual spare cell utilization rate is less than the desired spare cell utilization rate, computing additional area required in the bounding box for attaining the desired spare cell utilization rate, and inserting in the description of the integrated circuit design one or more spare cells within the bounding box to completely fill the additional area.