Systematization of Non-Charging Exposure Conditions in Electron Beam Lithography

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K04519
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 21060:Electron device and electronic equipment-related
• Research Institution: Osaka Institute of Technology
• Principal Investigator: KOTERA MASATOSHI 大阪工業大学, 工学部, 教授 (40170279)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 電子ビームリソグラフィ / レジスト帯電現象の解析 / 静電気力顕微鏡 / 電子ビーム誘起導電現象 / 無帯電条件 / フォギング電子

Outline of Final Research Achievements

We introduced an electrostatic force microscope that we originally developed into the existing scanning electron microscope and measured the resist surface potential immediately after electron beam exposure. We found that there are two exposure conditions under which the resist surface potential becomes charge-free when the electron beam acceleration voltage is 30 kV, and proposed the mechanism of positive charge and negative charge, and confirmed its validity. In order to systematize the charge-free exposure conditions, we varied the acceleration voltage from 0.5 kV to 30 kV and investigated the dependence of the surface potential on the exposure dose. On the other hand, since it takes a long time to measure the surface potential for a series of exposures for a single acceleration voltage, we developed a program to predict the surface potential for arbitrary acceleration voltages by deep learning.

Free Research Field

電子ビームリソグラフィ

Academic Significance and Societal Importance of the Research Achievements

最先端LSIを製造するにはSi基板表面の超微細加工技術が重要であり、その加工パターン原版となるフォトマスクを高精細にパターンニングすることが必須である。このための電子ビームリソグラフィ技術では、電気絶縁性の高いレジストが帯電して描画パターンが歪む現象を避けなければならない。我々はフォトマスクの電子ビームリソグラフィで帯電しない条件を発見した。本研究ではこの無帯電となる条件を体系化して広範囲露光条件で帯電の影響を受けないリソグラフィを実現しようとしている。