General purpose shape-based layout processing scheme for IC layout modifications

Abstract

Layout processing can be applied to an integrated circuit (IC) layout using a shape-based system. A shape can be defined by a set of associated edges in a specified configuration. A catalog of shapes is defined and layout processing actions are associated with the various shapes. Each layout processing action applies a specified layout modification to its associated shape. A shape-based rule system advantageously enables efficient formulation and precise application of layout modifications. Shapes/actions can be provided as defaults, can be retrieved from a remote source, or can be defined by the user. The layout processing actions can be compiled in a bias table.

We claim:  
     
         1 . A method for creating a photomask layout by applying optical proximity correction (OPC) to an integrated circuit (IC) layout, the method comprising the steps of: 
 defining a first OPC action, the first OPC action being associated with a first shape, the first shape comprising a plurality of coupled edges;    scanning the IC layout for a first set of features matching the first shape; and    applying the first OPC action to the first set of features to generate a first portion of the photomask layout.    
     
     
         2 . The method of  claim 1 , further comprising the steps of: 
 defining a second OPC action, the second OPC action being associated with a second shape, the second shape comprising a plurality of coupled edges distinguishable from the first shape;    scanning the IC layout for a second set of features matching the second shape; and    applying the second OPC action to the second set of features to generate a second portion of the photomask layout.    
     
     
         3 . The method of  claim 1 , further comprising the steps of: 
 defining a second OPC action, the second OPC action being associated with a single edge;    scanning the IC layout for a second set of features matching the single edge, the third set of features being distinct from the first set of features;    applying the second OPC rule to the second set of features to generate a second portion of the photomask layout; and    combining the first and second portions of the IC layout with the portion of the IC layout not included in the first and second sets of features.    
     
     
         4 . The method of  claim 2 , wherein the step of applying the first OPC action is performed before the step of applying the second OPC action, the first shape having a greater complexity than the second shape, the second set of features being selected from the portions of the IC layout not including the first set of features.  
     
     
         5 . The method of  claim 2 , wherein the step of applying the first OPC action is performed before the step of applying the second OPC action, the second shape having a greater complexity than the first shape.  
     
     
         6 . A system for applying optical proximity correction (OPC) to an integrated circuit (IC) layout, the system comprising: 
 a catalog of shapes, each of the shapes comprising at least two edges coupled in a prespecified manner; and    means for comparing the catalog of shapes with the IC layout.    
     
     
         7 . The system of  claim 6 , further comprising: 
 a library of actions, wherein each of the actions is associated with one of the shapes; and    means for applying the actions to the IC layout.    
     
     
         8 . The system of  claim 7 , wherein at least some of the actions controls application of a layout modification.  
     
     
         9 . The system of  claim 7 , further comprising means for resolving shape conflicts.  
     
     
         10 . The system of  claim 7 , further comprising means for resolving action conflicts.  
     
     
         11 . A photomask created from an integrated circuit (IC) layout, wherein the IC layout comprises a plurality of layout features, the photomask comprising: 
 a substantially transparent substrate; and    a substantially opaque layer forming a photomask pattern on the substantially transparent substrate,    wherein the photomask pattern includes at least one layout modification formed by an optical proximity correction (OPC) action associated with a shape matching one of the plurality of layout features, the shape comprising at least two edges coupled in a specified manner.    
     
     
         12 . An integrated circuit (IC) created using a photomask, the photomask comprising at least one layout modification formed using an optical proximity correction (OPC) action associated with a shape, the shape comprising at least two edges coupled in a specified manner.