A lithographic projection apparatus includes an illumination system, an interchangeable upper optics module, and a lower optics module. The illumination system provides a beam of radiation. The interchangeable upper optics module receives the beam and includes, sequentially, a beam splitter that splits the beam into portions, an aperture plate, and a plurality of reflecting surfaces. The lower optics module receives portions of the beam from respective ones the reflecting surfaces and directs the portions of the beam onto a substrate. Interference fringes or contact hole patterns are formed on the substrate using the portions of the beam.