Offset fill

Techniques are described for increasing the density of structures in a layout circuit design, while reducing undesired total interconnect capacitance that might otherwise be created by the increase in structure density. Data representing a pattern of fill structures is added to the fill regions of the design for one of the layers. Data representing a pattern of fill structures then is added to the fill regions of the design for another of the layers adjacent to the first layer. In the design for the second conductive layer, however, the pattern of fill structures is offset from the pattern of fill structures added to the design for the first layer in a direction substantially parallel to the layers. The offset may be selected to minimize or otherwise reduce the amount of overlap between the fill structures along a direction substantially perpendicular to the layers, thereby reducing the total interconnect capacitance associated with the layers.