Auto-routing small jog eliminator
View Patent ↗In a method of routing a wire to a shape in an integrated circuit for minimizing undesirable jog creation during a masking process, a plurality of possible placements of the wire relative to a selected edge of the shape resulting in the wire being connected to the shape are determined. A cost is assigned to each placement, the cost indicating an amount of jog that would be created in the masking process corresponding to the placement, wherein a greater cost indicates that a greater jog would be created in the masking process than would be created by a placement assigned a lesser cost. A placement having a lowest cost of the plurality of possible placements is selected.
1. A method of routing a wire to a shape in an integrated circuit for minimizing undesirable jog creation during a masking process, comprising the actions of:
a. using a computer, determining a plurality of possible placements of the wire relative to a selected edge of the shape resulting in the wire being connected to the shape;
b. assigning a cost to each placement, the cost indicating an amount of undesirable jog that would be created in the masking process corresponding to the placement, wherein a greater cost indicates that a greater undesirable jog would be created in the masking process than would be created by a placement assigned a lesser cost, wherein the assigning a cost action comprises the actions of:
i. assigning a zero cost to a placement when an outer edge of the wire is flush with the selected edge of the shape;
ii. assigning a minimum non-zero cost to a placement when the outer edge of the wire is at least a minimum feature distance away from the selected edge of the shape; and
iii. assigning a cost greater than the minimum non-zero cost to a placement when the outer edge of the wire is not flush with the selected edge of the shape and is less than the minimum feature distance away from the selected edge of the shape; and
c. selecting a placement having a lowest cost of the plurality of possible placements.
2. The method of claim 1 , wherein the cost is greatest as the outer edge of the wire approaches the selected edge of the shape and decreases to the minimum non-zero cost as the outer edge of the wire approaches the minimum feature distance away from the selected edge of the shape.
3. The method of claim 1 , wherein the minimum feature distance equals a minimum width allowable for the wire.
4. The method of claim 1 , wherein the action of assigning a cost greater than the minimum cost comprises the actions of:
a. defining plurality of quantum distances from the selected edge of the shape to the outer edge of the wire; and
b. assigning a quantum cost to each of the plurality of quantum of distances so that each quantum distance is assigned a correspondingly increased quantum cost above the minimum non-zero cost as the quantum distance between outer edge of the wire and the selected edge of the shape approaches a minimum non-zero quantum distance.
5. The method of claim 1 , adapted to execute on a digital computer.
6. The method of claim 1 , adapted to be part of an auto-router.
7. A method of routing a wire to a shape in an integrated circuit, comprising the actions of:
a. using a computer, determining a plurality of possible placements of the wire relative to a selected edge of the shape resulting in the wire being connected to the shape;
b. determining an amount of undesirable jog that will be created during a masking process for each of the plurality of possible placements, wherein the action of determining an amount of undesirable jog comprises the action of assigning a cost to each placement, the cost indicating an amount of undesirable jog that would be created in the masking process if the placement is selected, wherein a greater cost indicates that a greater undesirable jog would be created in the masking process than would be created by a placement assigned a lesser cost, wherein the assigning a cost action comprises the actions of:
i. assigning a zero cost to a placement when an outer edge of the wire is flush with the selected edge of the shape;
ii. as signing a minimum non-zero cost to a placement when the outer edge of the wire is at least a minimum feature distance away from the selected edge of the shape; and
iii. assigning a cost greater than the minimum non-zero cost to a placement when the outer edge of the wire is not flush with the selected edge of the shape and is less than the minimum feature distance away from the selected edge of the shape; and
c. selecting a placement of the plurality of possible placements that will create a smallest amount of undesirable jog during the masking process.
8. The method of claim 7 , wherein the minimum feature distance equals a minimum width allowable for the wire.
9. The method of claim 7 , wherein the cost is greatest as the outer edge of the wire approaches the selected edge of the shape and decreases to the minimum non-zero cost as the outer edge of the wire approaches the minimum feature distance away from the selected edge of the shape.
10. The method of claim 7 , wherein the action of assigning a cost greater than the minimum cost comprises the actions of:
a. defining plurality of quantum distances from the selected edge of the shape to the outer edge of the wire; and
b. assigning a quantum cost to each of the plurality of quantum of distances so that each quantum distance is assigned a correspondingly increased quantum cost above the minimum non-zero cost as the quantum distance between outer edge of the wire and the selected edge of the shape approaches a minimum non-zero quantum distance.
11. The method of claim 7 , adapted to execute on a digital computer.
12. The method of claim 7 , adapted to be part of an auto-router.
13. A wire routing system, configured to execute on a digital computer, for routing a wire to a shape in an integrated circuit for minimizing undesirable jog creation during a masking process, comprising:
a. a placement generator configured to generate a plurality of possible placements of the wire relative to a selected edge of the shape resulting in the wire being connected to the shape;
b. a cost generator that assigns a cost to each placement, the cost indicating an amount of undesirable jog that would be created in the masking process if the placement is chosen, wherein a greater cost indicates that a greater undesirable jog would be created in the masking process than would be created by a placement assigned a lesser cost, wherein the cost generator is configured to:
i. assign a zero cost to a placement when an outer edge of the wire is flush with the selected edge of the shape;
ii. as sign a minimum non-zero cost to a placement when the outer edge of the wire is at least a minimum feature distance away from the selected edge of the shape; and
iii. assign a cost greater than the minimum non-zero cost to a placement when the outer edge of the wire is not flush with the selected edge of the shape and is less than the minimum feature distance away from the selected edge of the shape; and
c. a placement selector that selects a placement assigned a lowest cost.
14. The wire routing system of claim 13 , wherein the cost is greatest as the outer edge of the wire approaches the selected edge of the shape and decreases to the minimum non-zero cost as the outer edge of the wire approaches the minimum feature distance away from the selected edge of the shape.
15. The wire routing system of claim 13 , wherein to assign a cost greater than the minimum cost, the cost generator is configured to:
a. define plurality of quantum distances from the selected edge of the shape to the outer edge of the wire; and
b. assign a quantum cost to each of the plurality of quantum of distances so that each quantum distance is assigned a correspondingly increased quantum cost above the minimum non-zero cost as the quantum distance between outer edge of the wire and the selected edge of the shape approaches a minimum non-zero quantum distance.
16. The wire routing system of claim 13 , adapted to be part of an auto-router.