Hokkaido University Research Profiles

Nanotechnology / Materials

Advanced Nano-optical Lithography Using Plasmons

Optical lithography technology with single-nanometer processing resolution

Using localization of the photoelectric field by plasmon resonance, the photoelectric field can be freely localized in a small area. With this technology, we have invented optical lithographic technology with a resolution of several nm by using the scattered light of the higher-order resonance mode of the plasmon.

Content of research

While the resolution of conventional optical lithography is determined by the wavelength, this lithographic technology is determined by the processing resolution of the metal nanostructure of the photomask. By irradiating the metal nanostructure of the photomask with infrared light, this technology can transfer patterns with the resolution of a single nanometer. This technology is unique since the shape of the mask pattern can be transferred as such by simply irradiating it with infrared light, high aspect ratio processing is expected because light propagation is used instead of near-field light, and it is possible to not only produce line and space patterns but also triangle, nano-gap, chain, and other shapes. It is expected to apply this technology to photonic crystals, plasmonic solar cells, and the technology for moth-eye structure formation on the surface of optical elements, which requires the transfer of nano-patterns over a relatively large area.

  • Photoresist nanopatterns formed by plasmon lithography

Potential for social implementation

  • ・Laser nano processing
  • ・Optical recording/reading
  • ・High-resolution optical microscope technology
  • ・Photonic crystals and plasmonic solar cells
  • ・Moth-eye structure formation technology
  • ・10 nm-node lithographic technology

Appealing points to industry and local governments

It is possible to transcribe desired nano-patterns by simply irradiating laser light on a photomask formed on a glass or semiconductor substrate in close proximity. It is expected to have a wide range of applications, including transcription not only on photoresist but also on polymers and glass. The mask can be used many times and the system is simple, so industrial applications are anticipated.

Intellectual property related to this research

PCT/JP2011/001192 「フォトレジストパターンの作製方法」
(日本:特許第5652887号 米国:特許第8,895,235号 蘭:特許第2544218号)
特許第4887502号  「金属構造体およびその製造方法」