Masahiro Takeo

We have completed a system that can achieve both deep x-ray lithography and submicron x-ray lithography with a single beamline by introducing the combination of x-ray plane and cylindrical mirrors. This x-ray lithography system can provide a large-scale microfabrication processing with 210 × 300 mm2 (A4 size). To exploit multiscale lithography, the beamline has a beam transport vacuum duct with a two-stage stacked structure and a 5-axis stage. This two-stage stacked structure allows us to fabricate both micron scale structures with high aspect ratios and submicron scale structures using the same beamline. In addition, x-ray imaging and computer tomography (CT) system are connected to the x-ray lithography system for nondestructive inspection and evaluation of the fabricated microstructures. The x-ray imaging system constructed this study has a relatively low energy range of x-ray energy in the beamline, which is in the range of 2–15 keV or less. Therefore, relatively good absorption contrast can be obtained for plastic materials, biomaterials, and the like. Since nondestructive imaging of the processed shape by x-ray lithography is possible, it is a very useful system in processing and evaluation can be performed simultaneously. This system also enables us to obtain the live images with keeping the creature alive in liquid using an indirect x-ray imaging system which converts x-ray images to visible light images through the fluorescent plate.

Mixing is difficult in microfluidic devices due to the low Reynolds’ number. We proposed and demonstrated a surface-acoustic-wave (SAW)-based microfluidic system which can control the temperature by mounting a heater. This device has a hollow cylindrical reservoir made of resin on a piezoelectric substrate (LiNbO3), and the solution can be rotated by injecting SAWs from both sides, which are shifted parallel to the central axis of the reservoir. 0.75 W of power was supplied to the IDT to generate SAWs, and the temperature rise of the liquid was measured with a thermographic camera when 0 to 0.55 W of power was supplied to the heater. As a result, by mounting the heater on the SAW actuator, it was possible to uniformly raise the temperature of a 40 µL micro-liquid by 8 to 40 °C in about 80 seconds, demonstrating the usefulness of this heater-mounted SAW agitation device.