From overall equipment efficiency (OEE) to overall Fab effectiveness (OFE)

Abstract

The metrics of the SEMI standard E79 offers a good method to calculate the overall equipment efficiency (OEE) and finds increasing application and acceptance in the semiconductor industry. To effectively apply E79, communication with the host using the SEMI SECS and GEM standards is required. Beyond the application of the communication standards, equipment models for the different tools and especially for cluster tools have to be created. Up to now, there are no standardized OEE models available. The paper will give examples of modeling methods, models, and also of software tools for the calculation and monitoring of OEE. However, successful analysis on OEE only is not sufficient as no machine is isolated in a factory, but operates in a linked and complex environment. A wider approach has to focus also on the performance of the whole factory. The characterization of a semiconductor factory by qualified metrics is rather complicated and difficult. So far, no standardized methods and metrics are available. Different methods and metrics introduced in the literature are presented in the paper. All methods have in common that they do not directly consider the costs. Including cost analysis would require the use of metrics for characterization of overall Fab effectiveness (OFE) in order to obtain a result for the cost per die out.