Decision support and analysis tool for planning in a semiconductor manufacturing facility

摘要

Abstract: As part of the recently completed MicroelectronicsManufacturing Science and Technology (MMST) project, adecision support and analysis tool for planning in asemiconductor manufacturing facility has beendeveloped. Design of the planning system uses anobject-oriented approach, and implementation isperformed in the Smalltalk programming environment. Thesystem continually maintains a plan for wafer releaseinto a facility, and predicts processing completiondates. The system has been built to run in adistributed environment, allowing simultaneous users indifferent parts of the facility. The system alsoprovides several types of what-if analysis, both on theexisting production plan and on production data.Production plan analysis is used to assist in makingoperational decisions related to the facility in itscurrent state, such as determining the least disruptivetime to take a piece of equipment down for maintenance.Production data analysis, which can be performedindependent of the production plan, determinesinformation such as equipment throughput rates toachieve given product cycle-times. All planning isperformed using artificial intelligence searchtechniques, and is based on a time-phased capacitymodel of the facility. Uncertainty inherent inproduction data, such as cycle-times, is modeled usingfuzzy arithmetic. This tool was used during the final1000 wafer demonstration for MMST, and is currentlybeing installed in other semiconductor manufacturingfacilities. This paper describes the main goals of theplanning system, the overall approach to planning andanalysis, and a brief description of the currentstatus. !11