Production improvements using a forward scheduler

摘要

One of the fabricators at the IBM Microelectronics Division'smanufacturing facility in Essex Junction, Vermont, is a high volumeproducer of DRAM's and advanced logic products. The wafer processingline is controlled by several custom software systems distributed overmultiple mainframe host computers. The IBM Forward Scheduler used inthis fabricator is a product scheduling system that provides anenvironment where information from many CIM system data sources can beintegrated. Four times each day, data is automatically downloaded to anIBM RS/6000 workstation from sources containing information related towork in progress (WIP), product routings, operations, parts, and tools.The data is inspected, processed and converted to a file formatconsistent with Tyecin's `ManSim' software, a commercial manufacturingsimulator. A simulation of the manufacturing line is run for 48 hours,generating several short-term dispatch reports by fabricator, area, andworkstation. The reports, which contain hourly projections of productmovement, are then uploaded from the RS/6000 to a VM machine, viewed andused by manufacturing personnel for future tool and labor allocation(e.g., scheduling of meetings, preventive maintenance, overtime andvacation, and tool deployment). This paper describes the software systemand interfaces of the Forward Scheduler as well as the issues involvedwith calibrating a short-term line simulator, how manufacturingpersonnel use the simulated data, and the system design features thatminimize maintenance on the Forward Scheduler