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.

Abstract: Some embodiments of the invention provide a method for defining wiring directions in a design layout having several wiring layers. The method decomposes a first wiring layer into several non-overlapping regions. It assigns at least two different local preferred wiring directions to at least two of the regions. In some embodiment, the method decomposing the first wiring layer by using the vertices of items in the layout to decompose the layout. In some of these embodiments, the item include macro blocks. The method of some embodiments also identifies several power via arrays on the first wiring layer, and identifies a local preferred wiring direction based on the arrangement of the power via arrays on the first wiring layer.

Abstract: Some embodiments of the invention provide a Local Preferred Direction (LPD) wiring model for use with one or more EDA tools (such as placing, routing, etc). An LPD wiring model allows at least one wiring layer to have a set of regions that each have a different preferred direction than the particular wiring layer. In addition, each region has a local preferred direction that differs from the local preferred direction of at least one other region in the set. Furthermore, at least two regions have two different polygonal shapes and no region in the set encompasses another region in the set. Some embodiments also provide a Graphical User Interface (GUI) that facilitates a visual presentation of an LPD design layout and provides tools to create and manipulate LPD regions in a design layout.