Increase Vacuum Processing Throughput and Yield Using Advanced Downstream Pressure Control Methods

Abstract
Vacuum process tool throughput and yield rates can be significantly affected by the performance level of chamber pressure control. Faster step transitions and more precise pressure control are often desired or needed to enhance tool productivity or increase production yields.

Nor-Cal Products makes this technology available in its Intellisys™ product line. The technology revolves around a new method of operating a variety of stepper motor driven downstream control valves (such as butterfly, poppet, gate and pendulum). In essence, it combines closed loop stepper motor control with an advanced pressure control algorithm allowing such valves to be controlled in ways never before possible. As a result of the exceptionally fast valve actuation and ultra-high position resolution, throughput increases up to 15% coupled with significant yield improvements and 100-fold scrap reduction have been realized saving vacuum processors millions of dollars per year.

This paper covers a description of the closed loop motor control technology that makes the enhanced valve actuation possible followed by a parametric comparison of different downstream pressure control methods.

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Reproduced with permission of the Society of Vacuum Coaters from the 44th (2001) SVC Annual Technical Conference Proceedings, pp 501-502. Contact SVC at svcinfo@svc.org to order a copy of the entire Proceedings for this conference.