Haruhito Ono

Position measurement method for alignment in UV imprint using a high index mold and “electronic” moiré technique

In UV imprint, positioning errors can occur between a mold and a wafer due to pressure when there is a contact with the UV resin. The moire technique, which is produced by superimposition of two gratings, is a well-known and simple method for high-resolution position measurement. However, the authors believe that a direct observation of two separate gratings is more appropriate for higher positioning accuracy. Here they propose a new method for the position measurement, which obtains “electronic” moire fringes by combining the images of two separate gratings from different areas of the mold and the wafer. The fundamental detection error was σ=0.15nm. The repeatabilities of the total system was σ=0.68nm in air and σ=0.73nm in resin. The linearity of the measurement value to control signal was R2=0.97.

Fabrication of Three-Dimensional Photonic Crystal Device for Terahertz Wave

We have fabricated a simple-cubic-lattice photonic crystal (PhC) device based on high-resistivity silicon in the terahertz (THz) range by micro-electro-mechanical system (MEMS) techniques. The lattice constant of the three-dimensional (3D) PhC device is 120 µm, resulting in a photonic band gap (PBG) centered at 1 THz. The 3D PhC device was constructed by stacking ten 120-µm-thick chips with periodic pillars and holes patterned respectively on both of their sides by Si deep reactive ion etching. By THz time-domain spectroscopy, the PBG of the device was observed between 0.83 and 1.17 THz in the Γ–Z direction with a transmittance attenuation of about 35 dB, which is in good agreement with a numerical calculation result.

Investigation of Dual-Focal-Points Optical System with Bright-Field Illumination and Image Processing for UV Nanoimprint Alignment

In this study, a new wide-gap alignment technique was developed for the investigation of dual-focal-points optical system with bright field illumination and image processing for UV nanoimprint.