Professor Masayoshi Mizutani and Colleagues Clean Up Polishing Processes with Nanobubbles: High-Precision Evaluation of Surface-Modified Layers at NanoTerasu
A research group led by Professor Masayoshi Mizutani of the Research Center for Green X-Tech at Tohoku University’s Organization for Advanced Research and Education, along with Ms. Yuko Akabane of TDC Corporation (who is also a graduate student at Tohoku University), has successfully demonstrated the effectiveness of a new method using ultrafine bubbles (UFBs, or nanobubbles) as a polishing auxiliary agent, aiming to reduce environmental impact in the polishing process.
In the manufacturing of semiconductors and MEMS, large amounts of chemical agents are typically used as polishing auxiliaries to achieve atomically smooth surfaces; however, wastewater treatment and cleaning costs remain significant challenges. This study investigated the “surface modification” mechanism, where the reactive species generated during the collapse of UFBs finely oxidize and embrittle the surface, making it easier to material-remove.
By conducting hard X-ray photoelectron spectroscopy (HAXPES) at NanoTerasu, a 3GeV high-brilliance synchrotron radiation facility, the team precisely evaluated the ultra-thin surface-modified layers. The results confirmed that modified layers (brittle layers) optimal for polishing were significantly formed on both carbon steel and aluminum alloys. This achievement scientifically demonstrates the potential of UFBs to function as an alternative polishing auxiliary agent to conventional chemicals.
These findings were published in the Journal of the Japan Society for Abrasive Technology on April 10, 2026. Moving forward, the research group aims to expand the range of applicable materials and advance the development of equipment and processes, striving to realize a clean, ultra-precision machining technology that does not rely on chemical agents.
For more details, please see the press release article (PDF) below.
[Paper Information]
・Journal: Journal of the Japan Society for Abrasive Technology
・Title: Potential of Ultrafine Bubbles as a Polishing Auxiliary Agent: Evaluation of Surface-Modified Layers Using Hard X-ray Photoelectron Spectroscopy at NanoTerasu
・Authors: Yuko Akabane, Masashi Abukawa, and Masayoshi Mizutani* (*Corresponding Author)
・Affiliation: The Research Center for Green X-Tech, Organization for Advanced Research and Education, Tohoku University (Concurrent positions: Graduate School of Engineering / Graduate School of Biomedical Engineering, Tohoku University)
・Publication Date: April 10, 2026
・DOI: 10.11420/jsat.25-00003