Hydrostatic ionic liquid-lubricated fluid film bearing for a rotational electron-beam lithography system

• Published in: Precision engineering Vol. 61; pp. 194 - 203
• Main Authors: Okabe, Takao, Sasaki, Shinya, Kondo, Yukishige, Miyatake, Masaaki, Yoshimoto, Shigeka
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.01.2020
• Subjects: High vacuum; Hydrostatic bearing; Ionic liquid; Ionic magnetic fluid; Magnetic fluid seal; Outgassing; Outgassing; Ionic magnetic fluid; Hydrostatic bearing; Magnetic fluid seal; High vacuum; Ionic liquid
• ISSN: 0141-6359; 1873-2372
• DOI: 10.1016/j.precisioneng.2019.10.008

Rotational electron-beam mastering (REBM) systems have been studied with the aim of achieving the high data density necessary to facilitate the fabrication of next-generation optical data media, such as holographic storage. This study reports the design and testing of an ionic liquid (IL)-lubricated hydrostatic spindle system comprising an IL bearing, IL supply pump, and ionic magnetic fluid seal; and its outgassing performance under high-vacuum conditions. An inner vacuum chamber pressure of approximately 10−4 Pa was maintained during rotation of the spindle system. The outgassed products, as measured by a quadrupole mass spectrometer, were primarily generated from the air components in the lubricant IL. The non-repeatable runout in the radial direction, which is an important parameter of REBM accuracy, was 100 nm for a rotational speed of less than 130 min−1. The proposed method can be used for a 100-nm scale REBM device. •A high-vacuum-compatible hydrostatic spindle using ionic liquid was proposed.•The proposed spindle can rotate with high-accuracy and low outgassing in high-vacuum.•The outgassing from the spindle with ionic liquid circulation mechanism was investigated.•The usefulness of the spindle for an electron-beam lithography device was shown.