Image Number 4 for United States Patent #7802226.
A method for preparing data to create two or more masks required to print a desired feature pattern with a multiple mask technique. In one embodiment of the invention, a target feature pattern is separated into two or more groups or data layers with a coloring algorithm. Coloring conflicts or adjacent features that are within a predetermined distance of each other and are assigned to the same group or data layer are identified. Cutting boxes are added to a feature to divide a feature into two or more smaller features. A coloring algorithm is re-applied to the layout including the cutting boxes to assign the features into different groups or data layers. Data in each group or data layer is used to define a mask to print the target feature pattern.