A variety of lens aberration effects degrade lithographic performance metrics such as resolution, image fidelity, pattern placement, and best focus. Additionally, these may be different for different pattern orientations. Resolution enhancement techniques, necessary for low k1 imaging, often amplify these undersirable effects, degrading the optimum process window obtainable for an aberration-free lens. The magnitude of the aberration effect depends, among other things, on the illumination condition represented by the numerical aperture and the pupil fill as well as the pattern layout itself. Many lithographic test structures exist to characterize primary aberrations [Piston, tilt, defocus, astigmatism and coma]. However, it is difficult to extract information about higher order lens imperfections. These higher-order effects can seriously degrade imaging when complex reticle patterns [i.e. non-orthogonal layouts] are used. Therefore, we have developed a simple test structure to capture these high order effects.