A Simulation Model to Characterize Photolithography Process of a Semiconductor Wafer Fabrication

The pressures on semiconductor manufacturers due to cost considerations, rapid growth of process technology, quality constraints, feature size reduction, and increasingly complex devices are increasing requiring ever higher efficiency from the manufacturing facilities. The complexity of manufacturing high capacity semiconductor devices means that it is impossible to analyze the process control parameters and the production configurations using traditional analytical models. There is, therefore, an increasing need for effective models of each manufacturing process, characterising and analyzing the process in detail, allowing the effect of changes in the production environment on the process to be predicted. The photolithography process is one of the most complex processes in a semiconductor manufacturing environment. Using state-of-the-art computer simulation and a structured modelling methodology a generic model of photolithography flexible manufacturing cells has been developed and used to mimic actual performance of the tools. Comparison of the output from the model with data from the plant showed the quality of the model. This paper discusses the technique used to develop the simulation model to characterize the photolithography process tools. Details on the structured modelling approach taken to develop reusable simulation models have also been presented. Conclusions and recommendations to maximize the process performance and reduce risk have been included.