ABC: A better control for manufacturing

ABC is a generic methodology to improve the quality of manufacturing. It can optimize operation of a single process or an entire factory to meet or exceed product specifications. ABC is based on three nets which continually interact to model processes and to provide local process control and global product optimization. Significant process variables are identified, evaluated, and ranked according to their contributions to product quality. Process performance, which determines product quality, is characterized by a sensitive parameter, the Q-factor, which is used for local control and for global optimization. Real-time response maps capture process behavior and identify current status, improved operating points, and expected improvement in relation to design targets. ABC continually compensates for off-specification manufacturing steps by feedforward-and-feedback corrective actions which keep the product on target. ABC also evaluates and ranks the effects of non-numeric manufacturing variables, such as specific tools and vendors, on product quality. Total quality control can be achieved by optimizing all variables, both sensor-based and non-numeric, which control the product. Some of ABC's capabilities are demonstrated in a multistep fabrication of a semiconductor capacitor in which the electrical properties of the product are optimized by controlling the individual chemical process steps. ABC's capacity to minimize scrap and rework by compensating for out-of-control conditions is demonstrated in this example. A functional subset of ABC currently exists as a menu-driven tool, implemented in APL2® on VM/CMS for mainframe computers and in the C language for workstation platforms: RS/6000 running under AIX® and PS/2® under OS/2®. ABC is available, in the workstation version, as an IBM Program Offering under the name QuMAP™—A Better Control, and is currently used in the semiconductor, pharmaceutical, chemical, and consumer goods industries.