Development of a Small Residual Gas Analyzer Utilizing the Quadrupole Array Structure — Micropole System ~ QL Series ~ —

By: Hirokazu Kitaura

31 August 2011


The Micropole System is one of the world’s smallest residual gas analyzers (RGAs). HORIBA STEC first obtained a license to an intellectual property right from Ferran Scientific Inc., (a U. S. company) and has developed this new system by adding the company’s own proprietary design elements. To control the “quality of a vacuum,” it isn’t sufficient to simply control the level of vacuum achieved with the use of an ion gauge or the like. It’s also important to monitor the vacuum quality, including the composition of gases that are present, by using a device such as an RGA. The RGA has quite a long history. By the 1950s its basis had already been established by Paul et al.[1] as quadrupole mass analysis technology. To this day, various manufacturers have continued to introduce RGAs developed by utilizing similar principles, although such RGAs are often employed only in high vacuum regions up to a maximum ambient pressure of 10-2 Pa in the operating environment. Under such circumstances, if RGAs that can be used in the intermediate vacuum region (for example, 10-1 Pa or above) become available, during certain processes it will not only be possible to measure the residual gases in a chamber (of manufacturing equipment) evacuated to a vacuum but also to conduct continuous measurement, even during the process. Based on the development discussed in this article, we have commercialized a product by carrying over the concept of an “RGA that can measure even in the intermediate vacuum region”[2, 3], as demonstrated in Ferran Scientific’s miniature RGAs, while improving quality and reliability and incorporating many user-friendly features, including “PC-free (without using a personal computer) usability,” that have not been available in previous RGAs.

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