Systen and method for position control of a mechanical piston in a pump

Abstract

Embodiments of the systems and methods disclosed herein utilize a brushless DC motor (BLDCM) to drive a singie-stage or a multi-stage pump in a pumping system for real time, smooth motion, and extremely precise and repeatable position control over fluid movements and dispense amounts, useful in semiconductor manufacturing. The BLDCM may employ a position sensor for real time position feedback to a processor executing a custom field-oriented control scheme. Embodiments of the invention can reduce heat generation without undesirably compromising the precise position control of the dispense pumpby increasing and decreasing, via a custom control scheme, the operating frequency of the BLDCM according to the criticality of the underlying function(s).; The control scheme can run the BLDCM at very low speeds while maintaining a constant velocity, which enables the pumping system to operate in a wide range of speeds with minimal variation, substantially increasing dispense performance and operation capabilities.

Description

[0001] Cross References to Related Applications [0002] This application claims U.S. Provisional Patent Application No. 60 / 741660 (dated December 2, 2005, titled "SYSTEM AND METHOD FOR POSITIONCONTROL OF A MECHANICAL PISTON IN A PUMP") and 60 / 841725 (dated 2006 September 1, titled "SYSTEM ANDMETHOD FOR POSITION CONTROL OF A MECHANICALPISTON IN A PUMP") priority, so both documents are referenced herein. technical field [0003] The present invention generally relates to fluid pumps. In particular, embodiments of the invention relate to systems and methods for position control of mechanical pistons in motor-driven single-stage or multi-stage pumps used in semiconductor manufacturing. Background technique [0004] There have been many applications requiring precise control of the amount and / or rate of fluid dispensed by a pumping device. In semiconductor processing, for example, it is important to control the amount and rate at which photochemicals, such as photoresists, are...

AI Technical Summary

Problems solved by technology

These pressure spikes and subsequent pressure drops may damage the fluid (i.e. may adversely alter the physical characteristics of the fluid)

Additionally, pressure spikes may result in fluid pressure buildup, which may cause the dispense pump to dispense more fluid than intended, or to dispense fluid in a manner that has unfavorable dynamic characteristics

Also, since these problems are interrelated, sometimes fixing one problem can cause more problems and / or make things worse

[0007] Typically, pumping systems cannot satisfactorily control pressure changes during cycling

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