1. Field of the Invention
The present invention relates to an apparatus for a routing system, particularly to a routing system or a router that includes a model.
2. Description of the Related Art
Existing routers are software systems that accept two parts of information namely the user design data and the rules-constraints-costs data. A router of such art tries to route all nets in the user design according to the rules-constraints-costs description. The router produces a complete layout suitably for subsequent processing steps such as physical verification and tape-out to manufacturing.
Routing is generally divided into two steps: global routing and detail routing. For each net, global routing generates a pre-determined route for the interconnect lines that are to connect the pins of the net. After global routes have been created, the detail routing creates specific individual routing paths for each net.
Some methods are disclosed to reduce the size of the IC's and increase the efficiency of the layouts. U.S. Pat. No. 7,107,564, titled “Method and Apparatus for Routing a Set of Nets”, specifies a topological routing solution for a group of nets. The method initially identifies a set of initial routing solutions for each net in the group of nets. Each of a plurality of initial routing set of routing solutions has a plurality of topological routes. Each topological route is a route that represents a set of geometric routes that are morphable into one another. Next, the method specifies a best topological routing solution from the initially identified sets of topological routing solutions for the nets. The best routing solution has one route for each net in the group of nets. Although this method utilizes specifying a best topological routing solution from the topological routing solutions to optimize the integrated circuit layouts, it still needs a physical verification process to guarantee the manufacturability. When some violations occur, the IC designer has to modify the routes and executes the physical verification process. The steps are repeated until all violations are eliminated.
U.S. Pat. No. 7,086,447, titled “Method and Apparatus for Efficiently Locating and Automatically Correcting Certain Violations in a Complex Existing Circuit Layout”, modifies an existing large scale chip layout to reinforce the redundant via design rules to improve the yield and reliability. The method operates on each metal-via pair from bottom up to locate and correct isolated via rule violations by adding metal features and vias in a respective patch cell associated with each cluster cell. A large complex design is thus divided into cells. This method deals with the existing circuit layout. The steps of routing, checking, and correcting processes are repeated until all violations are eliminated.
When the integrated circuit is developed at sub-wavelength geometries, the route for the integrated circuit is complex. Therefore, a large amount of violations will occur by using the existing routers. The steps of routing, checking, and correcting processes are repeated. It is time-consuming.
One particular aspect of the present invention is to detail methods and apparatus for a routing system or router that includes a model. The model can be in many different forms including but not limited to: resolution enhancement technologies such as optical proximity correction (OPC), lithography model including but not limited to aerial image, pattern-dependent functions, functions for timing/signal integrity/power, manufacturing process variations, and measured silicon data.
A further particular aspect of the present invention is to reduce the violations when the integrated circuit is routed. For a complex integrated circuit, the steps of routing, checking, and correcting processes are substantially reduced.
In one embodiment, the model can be described as input to the system and the model calculator can interact either with the data structure or the query engine of the detail router or both. The model calculator can accept input as a set of geometry description and produce output to guide the query functions. An example technique called set intersection is disclosed herein to combine multiple models in the system. A preferred embodiment of this invention includes a full chip grid-based router being aware of manufacturability.
For further understanding of the invention, reference is made to the following detailed description illustrating the embodiments and examples of the invention. The description is only for illustrating the invention and is not intended to be considered limiting of the scope of the claim.
The drawings included herein provide a further understanding of the invention. A brief introduction of the drawings is as follows:
Note that multiple models can be deployed to the router 140 even though only a single model 130 is shown in
The description above only illustrates specific embodiments and examples of the invention. The invention should therefore cover various modifications and variations made to the herein-described structure and operations of the invention, provided they fall within the scope of the invention as defined in the following appended claims.
This patent application claims the benefit of the earlier-filed U.S. Provisional Patent Application entitled “Methods and Apparatus for a Routing System”, having Ser. No. 60/733,731, and filed Nov. 3, 2005.
Number | Date | Country | |
---|---|---|---|
60733731 | Nov 2005 | US |