Method and system for performing global routing on an integrated circuit design

1. A method for performing global routing on an integrated circuit design, said method comprising:

dividing said integrated circuit design into a plurality of G-cells using a computer system, wherein said plurality of G-cells are interconnected by a plurality of nets;

decomposing said plurality of nets into a plurality of corresponding wires;

prerouting some of said wires to connect said plurality of G-cells;

initiating a box around a region of said integrated circuit design in which wires are most congested;

performing a BoxRouting routine starting with wires within said box until all wires within said integrated circuit design are routed, wherein said BoxRouting routine includes

performing progressive integer linear programming (ILP) routing to route as many unrouted wires within said box as possible without incurring routing congestion;

performing adaptive maze routing to route any remaining unrouted wire within said box after said ILP routing performance; and

performing box expansion to expand said box on every direction such that a new box covers all of said box; and

performing postrouting on wires within said integrated circuit design.

2. The method of claim 1 , wherein said progressive ILP routing only routes wires inside said box and does not route any wire outside said box.

3. The method of claim 1 , wherein said progressive ILP routing utilizes G-cells inside said box and does not utilize G-cells outside said box.

4. The method of claim 1 , wherein said adaptive maze routing utilizes G-cells inside and outside said box.

5. The method of claim 1 , wherein said adaptive maze routing utilizes routing resources more aggressively when searching for a routing path inside said box than searching for a routing path outside said box.

6. A computer usable medium having a computer program product for performing global routing on an integrated circuit design, said computer usable medium comprising:

program product code for dividing said integrated circuit design into a plurality of G-cells, wherein said plurality of G-cells are interconnected by a plurality of nets;

program product code for decomposing said plurality of nets into a plurality of corresponding wires;

program product code for prerouting some of said wires to connect said plurality of G-cells;

program product code for initiating a box around a region of said integrated circuit design in which wires are most congested;

program product code for performing a BoxRouting routine starting with wires within said box until all wires within said integrated circuit design are routed, wherein said BoxRouting routine includes

performing progressive integer linear programming (ILP) routing to route as many unrouted wires within said box as possible without incurring routing congestion;

performing adaptive maze routing to route any remaining unrouted wire within said box after said ILP routing performance; and

performing box expansion to expand said box on every direction such that a new box covers all of said box; and

program product code for performing postrouting on wires within said integrated circuit design.

7. The computer usable medium of claim 6 , wherein said program product code for performing progressive ILP routing only routes wires inside said box and does not route any wire outside said box.

8. The computer usable medium of claim 6 , wherein said program product code for progressive ILP routing utilizes G-cells inside said box and does not utilize G-cells outside said box.

9. The computer usable medium of claim 6 , wherein said program product code for performing adaptive maze routing utilizes G-cells inside and outside said box.

10. The computer usable medium of claim 6 , wherein said program product code for performing adaptive maze routing utilizes routing resources more aggressively when searching for a routing path inside said box than searching for a routing path outside said box.