Designed to provide convenient and high resolution photolithography, the Karl Suss MA4 is the lab's premier contact aligner. It is designed to work with 4" wafers, though it's regularly used with chips of all sizes. It accepts 5 inch binary masks as well as transparency work-alikes. The greatest quality of the Karl Suss is the ease with which one can load masks and switch out samples. For that reason, it's the contact-aligner of choice for most users at CNM2. With proper alignment marks, it's possible to align features within a few hundred nanometers of each other. Additionally, the tool has an IR backside alignment option. The tool is appropriate for both g-line and i-line resists, including SU-8 and S1813, which it can pattern down to the micron resolution range. It's designed with options specifically to help with very thick resists, such as a mode to keep the mask and wafer slightly separated during exposure and a mode to expose slowly over a long period of time to reduce overheating. It's also designed with features to help with high resolution thin-resists, such as a mode to contact the wafer and mask with high force and create a vacuum chamber around them. We provide the Karl Suss MA4-1 and MA4-2 aligners which have slightly different light intensities and filters.