A system and method of auto-exposure control is provided for image acquisition hardware using three dimensional information to identify a region of interest within an acquired 2D image or images upon which to apply traditional auto-exposure techniques. Moreover, the ARCcapping layer is directly formed on the low-k material, thereby also preserving the integrity thereof during an etch and chemical mechanical polishing process. The press-fitting of the substrate unit is performed by a second radiation block which is screwed to push the first radiation block toward the cooling block. As the subfields are exposed, respective data are recalled and the exposure is performed with optical corrections made according to the data. The array of sensors is configurable in response to different criteria.