Copper electroforming replication process for soft x-ray mirrors

Gota Yamaguchi; Hiroto Motoyama; Shigeki Owada; Yuya Kubota; Satoru Egawa; Takehiro Kume; Yoko Takeo; Makina Yabashi; Hidekazu Mimura

doi:10.1063/5.0065684

Copper electroforming replication process for soft x-ray mirrors

Rev Sci Instrum. 2021 Dec 1;92(12):123106. doi: 10.1063/5.0065684.

Authors

Gota Yamaguchi¹, Hiroto Motoyama², Shigeki Owada³, Yuya Kubota⁴, Satoru Egawa⁵, Takehiro Kume⁶, Yoko Takeo³, Makina Yabashi³, Hidekazu Mimura¹

Affiliations

¹ Department of Precision Engineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
² Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
³ Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan.
⁴ RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan.
⁵ RIKEN Center for Advanced Photonics, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
⁶ Technology Center, Natsume Optical Corporation, 1200-29 Kawaji, Iida, Nagano 399-2431, Japan.

PMID: 34972441
DOI: 10.1063/5.0065684

Abstract

We developed a copper electroforming replication (CER) process to fabricate precise ellipsoidal mirrors for soft x-ray focusing. Some applications of ellipsoidal mirrors in x-ray microscopy require that all components that are close to samples, including the mirrors, are made of non-magnetic materials. In this study, a non-magnetic copper ellipsoidal mirror was fabricated by replicating a figured and super-polished quartz glass mandrel using an electroforming technique. It was found that the CER process has a high replication accuracy of 8 nm. The focusing performance of the mirror was characterized using a soft x-ray free-electron laser with a photon energy of 100 eV. A small focus size of 370 × 400 nm² was achieved with a high reflectivity of 65%.