US 7,412,682 B2Granted

Local preferred direction routing

AssigneeCadence Design Systems, Inc.

InventorsAnish Malhotra, Jonathan Frankle, Asmus Hetzel, Etienne Jacques

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Abstract

Some embodiments of the invention provide a method for routing. The method defines at least one wiring layer that has at least two regions with different local preferred wiring directions. The method then uses the differing local preferred wiring directions to define a global route on the wiring layer. The two regions are a first region with a first local preferred wiring direction, and a second region with a second local preferred wiring direction. The global route traverses the first region along the first local preferred wiring direction and traverses the second region along the second local preferred wiring direction.

Claims23

Dependent claims

A method of defining global routes in an integrated circuit (“IC”) layout comprising a plurality of layers, the method comprising:

a) defining a routing graph that comprises (i) a plurality of edges along a first local preferred direction defined for a first region of a particular layer of the IC layout, and (ii) a plurality of edges along a second local preferred direction defined for a second region of the particular layer, wherein the first and second local preferred directions are different;
b) defining the capacities of a plurality of edges based on the different local preferred wiring directions of the two regions;
and
c) defining a global route by performing at least one path search that uses the defined capacities of the edges to determine whether a particular edge from the plurality of edges comprises sufficient available capacity for a path expansion to use the particular edge, wherein a capacity defined for an edge is based on a maximum number of global routes allowed to use the edge.

1 more element

A computer readable medium storing a computer program for defining global routes in an integrated circuit (“IC”) layout comprising a plurality of layers, the computer program executable by at least one processor, the computer program comprising sets of instructions for:

a) defining a routing graph that comprises (i) a plurality of edges along a first local preferred direction defined for a first region of a particular layer of the IC layout, and (ii) a plurality of edges along a second local preferred direction defined for a second region of the particular layer, wherein the first and second local preferred directions are different;
b) defining the capacities of a plurality of edges based on the different local preferred wiring directions of the two regions;
and
c) defining a global route by performing at least one path search that uses the defined capacities of the edges to determine whether a particular edge from the plurality of edges comprises sufficient available capacity for a path expansion to use the particular edge, wherein a capacity defined for an edge is based on a maximum number of global routes allowed to use the edge.

1 more element

Dependencies are inferred from the claim text.