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Jennifer K. Robinson, FabTime Inc., Menlo Park, CA, USA

ABSTRACT

FabTime is focused on improving wafer-fab cycle times through consulting, training, and our web based digital dashboard software. For the past two years, we have conducted an informal survey of the roadblocks to great fab cycle-time performance. To date, the top response has been “equipment downtime”. In this article, we discuss several best practices for improving fab cycle time by focusing on tool uptime. We begin by summarizing the ways in which equipment downtime events (scheduled and unscheduled) affect cycle time, with emphasis on tool utilization and variability. We then offer suggestions for mitigating these effects. We conclude by proposing a series of uptime-related metrics that, if improved, will tend to improve cycle time, especially for bottleneck and single-path tools.