STATISTICAL PROCESS-CONTROL IN SEMICONDUCTOR MANUFACTURING

The fabrication of integrated circuits (IC's) has always promoted technical innovation. IC research and development, however, has traditionally been focused on improving the performance of the product, while paying relatively little attention to the efficiency of its production. Today, standard scientific manufacturing practices are finally finding their way into IC production. In most cases, the development of an industrial mentality coincides with the introduction of statistical process control (SPC). This paper undertakes a brief survey of standard SPC schemes, and illustrates them through examples taken from the semiconductor industry. These methods range from contamination control to the monitoring of continuous process parameters. Even as SPC is transforming IC production, the peculiarities of semiconductor manufacturing technology are transforming SPC. Therefore, the second part of this paper describes novel SPC applications which are now emerging in semiconductor production. These methods are being developed to monitor the short production runs that are characteristic of flexible manufacturing. Additional SPC techniques suitable for in situ multivariate sensor readings are also discussed