A Hierarchical Quantitative FMEA Framework for Reliability Enhancement of Laser Lithography Systems

Abstract

A hierarchical quantitative Failure Mode and Effects Analysis (H-FMEA) framework is developed for reliability assessment of laser lithography systems. Explicit representation of subsystem dependencies and failure propagation pathways enables risk evaluation across optical, mechanical, thermal, sensing, and control domains. Occurrence probabilities are incorporated through quantitative failure-rate modelling, while detection rankings are derived from observability measures obtained from diagnostic and metrology information. System-level risk is determined through a dependency-weighted aggregation process that captures interactions among coupled subsystems. Evaluation using a representative lithography functional chain reveals greater sensitivity to latent degradation mechanisms and compensation-masked failure modes than classical FMEA. Risk ordering becomes more selective, early fault recognition increases, and propagation-critical failure paths receive higher priority during assessment. The resulting formulation extends conventional FMEA toward propagation-aware reliability analysis for advanced manufacturing environments.