International standardization of methods for measuring cryopump performance

抄録

The cryopump is a gas accumulation type vacuum pump that condenses or adsorbs gas molecules on a cryogenic panel placed inside a vacuum vessel to perform pumping. It is widely used in semiconductor manufacturing equipment, FPD and optical thin film deposition equipment, and research chamber applications, as it has the advantages of high pumping speed for water and hydrogen, and the ability to achieve oil-free and clean ultra-high vacuum. The cryopump has unique specification defined by its pumping principle and structure, such as gas storage capacity and tolerance values for heat load (throughput, crossover), which are not found in other vacuum pumps. However, although there are overseas standards (AVS, Pneurop) regarding performance measurement methods for cryopumps, there was no JIS standard, and there had been no international standardization.In May 2019, a proposal for ISO standard development on performance measurement methods for cryopumps was made by China at the ISO TC112 Vacuum Technology Committee Kyoto Conference. It was approved in October 2020 and officially launched as a project. In Japan, ULVAC CRYOGENIC INCORPORATED, CANON ANELVA CORPORATION, and Sumitomo Heavy Industries, Ltd. took the lead in developing the standard, and after discussions at ISO international conferences, it was officially issued as ISO 21360-6 in December 2023. The adopted measurement methods as ISO standards generally follow the existing overseas standards, but new term definitions (base pressure cryogenic vacuum pump) and measurement methods (setup using gate valves) have been added, and it is considered to be a content that satisfies the Japanese side as well. In this presentation, we will first explain the overview of cryopumps and introduce the flow of ISO standard development and the contents of the issued standard.