VGM: an expert system supporting operators to repair facilities

VGM (visual guide maintenance system), an expert system which helps operators in the diagnosis and repair of minor but frequently occurring malfunctions of semiconductor manufacturing equipment, is described. The VGM has a plausible reasoning mechanism and a good human interface which displays both literal and visual instructions. The VGM was built on a diagnostic expert shell, D-IAL (diagnosis-intelligent automation language). The human interface of the VGM and the background of its design are described. The troubleshooting mechanism and other characteristics of D-IAL are reviewed. The experience and results of implementing the diagnostic knowledge for a projection aligner, in a system for use by a maintenance engineer, are discussed