Mask Aligner with Backside and Topside Alignment Capabilities. The scanning backside alignment is accomplished using an IR camera which detects infrared light transmitted through an IR transparent chuck, as well as the substrate and mask being aligned. The alignment microscope uses 5X, 10X and 20X objective lenses for either backside or topside alignment. For topside alignment the eyepieces are 12.5X. The exposure source is a 350W Hg lamp powered by a Suss Model 505 supply. The system incorporates UV-400 optics to transfer the energy to the substrate. The substrate may be exposed in soft or hard contact with both forms of alignment. Also in topside alignment the vacuum contact(high precision “HP”) is available.