As photolithography processes continue to increase in complexity, in order to maintain anticipated productivity it has become more challenging to increase the throughput, lower the rework rate and improve tool utilization. Manufacturing automation system deployed in a production site provides a source to monitor the photolithography process, the operation efficiency and the health of equipment. However, it is found to be a time-consuming and difficult process to analyze the large amount of data and determine the exact source of productivity hitter. Based on these needs, a new methodology is proposed in this paper to quantify the productivity hitter versus process, operation, and equipment. A tool is developed from this methodology to track through every tool operation time and operation steps based on information of tool event logs (event-based) via network. By applying the tool, an easy to view information can be quickly derived from the event log data, for rapid decision making such as lot disposition, recipe optimization, and equipment function check. The event-based methodology is introduced in this paper. In addition, several examples are studied by using this tool in ASIC type production environment. The effects of track delay, hidden overhead time, poor lot queuing and excessive error-assist time, etc. are studied and quantified. By applying the tool, the time taken to accurately locate the root cause of productivity hitter is significantly reduced. Based on the analysis, the guidelines are given to optimize the tool utilization and raw throughput, and the productivity is improved accordingly. Future works including fully integrated into in-house manufacturing automation are discussed.