US Patent 9626472 Method and system of forming layout design

A method of forming a layout design is disclosed. The method includes placing a first set of layout patterns in a first layout layer and placing a second set of layout patterns in a second layout layer. The first set of layout patterns is aligned with one or more grid lines of a first set of grid lines. The first set of grid lines extends along a first direction, where two grid lines of the first set of grid lines overlap two cell boundaries of a standard cell layout. The second set of layout patterns is aligned with one or more grid lines of a second set of grid lines. The second set of grid lines extends along the first direction and has at least two different line pitches, where two grid lines of the second set of grid lines overlap two cell boundaries of the standard cell layout.