Development of Simulator for Super-Precision Machining by Nano-Bubbles based on Computational Method

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K05147
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 26050:Material processing and microstructure control-related
• Research Institution: Tohoku University
• Principal Investigator: Ozawa Nobuki 東北大学, 未来科学技術共同研究センター, 特任准教授 (60437366)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: ウルトラファインバブル / 精密加工 / 化学機械研磨 / マルチフィジックス現象 / 反応分子動力学法 / 圧壊

Outline of Final Research Achievements

Ultra fine bubbles (UFBs) are used for highly efficient chemical mechanical polishing methods of difficult-to-process materials. When UFBs are crushed by a shock wave, a nanoscale jet flow is generated, leading to oxidizing the substrate for easier polishing. However, UFB is very stable, it is desirable to be easily crushed by a weak shock wave for efficient chemical mechanical polishing. In this study, the effects of the included gas, UFB size, and environment on the stability of UFBs were investigated by reactive molecular dynamics, which can take chemical reactions into account. The O2 molecule included in the UFB is more likely to cause gas inflow and outflow inside and outside the bubble, indicating that the bubble is more likely to be crushed. Moreover, our simulations showed that UFBs easily aggregate when ions are introduced into the solvent.

Free Research Field

計算科学

Academic Significance and Societal Importance of the Research Achievements

パワー半導体素子材料の成長基板であるAlN及びGaN基板は高硬度と高い化学安定性を有する難加工材料であり、低欠陥且つ高効率に研磨する手法の開発が強く求められている。そこで、研磨スラリーにウルトラファインバブル（UFB）を導入した化学機械研磨(CMP)手法が注目されており、UFBの圧壊時に生じるジェット流が基板の酸化を促進すると考えられている。そこで、さらなるCMPの高効率化には、安定なUFBを圧壊させやすい条件を解明する必要がある。本研究は反応分子動力学法に基づきUFBのサイズや環境がUFBの安定性に与える影響を検討したものであり、さらなる難加工材料の加工速度と高品質化への貢献が期待できる。