Automated process control loops running in semiconductor manufacturing facilities must be able to compensate for machine variations as well as identify differences between products. With a number of exposure tools, pattern levels, and active devices manufactured in a typical ASIC fab, for photo APC system must maintain thousands of control loops. Control loop context information in TI's Semiconductor Manufacturing System (SMS) is defined in a hierarchal fashion which allows default values in a manufacturing specification to be overridden for particular products or lots. ProcessWORKS APC software automatically adds new control loops for new devices and pattern levels to a defined model structure. This system scales well and supports hundreds of thousands of control loops from a single database server in TI fabs. Application of product specific control systems for alignment and exposure control has provided increased exposure capacity due to decreased reworks and setup time, a substantial reduction in engineering maintenance and improved process capability. The APC system has evolved into a requirement for leading edge photolithography processes in Texas Instruments.