Papers by Author: Young Eun Yoo

Abstract: We have developed a novel atomic force microscope (AFM) probe as a highly sensitive sensor and an application of the probe into various mechanical tests for characterizing micro/nanostructures. Using MEMS fabrication technique, we have designed and fabricated rhombus-shaped symmetric AFM probe. Adhesion forces between silicon tip and artificial nano-hair structures of cyclic olefin copolymer (COC) and polypropylene (PP) were measured using the probe with a flat tip. The results exhibited the usual characteristics of force-displacement curves of COC and PP nano-hair structures, in which a pull-off force was detected at the point of unloading. The average adhesion forces of the COC and PP hair structures are about 9.48 μN and 10.67 μN, respectively.

Abstract: An injection molding technology is developed to replicate pillars in micro/nano scale on the thin plastic substrate. Two types of pillar are to be replicated and one is square type of 10um x 10um, the other is circular type whose diameter is in range of 100 nm ~ 300 nm. For both types of the pillars, the height is about 250 nm. A pattern master is first fabricated on the photo resist(PR) layer spin coated to about 250nm of thickness on chrome/quartz plate by patterning e-beam writing and then developing the PR. The patterns on the PR master are transferred by nickel electro-plating to fabricate rigid nickel stamper. Using this nickel stamper, a substrate with nano pillars on its surface is injection molded by optimizing the conditions to fabricate DNA separating chip.