The nanocontact printing process of non-planar substrate was conducted on the substrate as coated with the metal thin film on which the mask's pattern was to be printed by using the flexible h-PDMS stamp. In this study, in order to embody non-planar nanocontact print, the following types of nanostructures which were respectively different in a pattern form, a pattern size and a line width: a straight line type, an oblique line type, an L type and an U type. The mask size is 5 x 5 x 0.9 inch, and the pattern form size is 100nm ~ 500nm where the line width ratio and the pattern space are different and the depth is 200nm. The flexible h-PDMS stamp was fabricated by using VDT-731, SIP 6831.1, Fluka 87927 and HMS-301 as a mold material. The flexible h-PDMS stamp with a high resolution corresponds exactly to the master pattern, and could be replicated a pattern up to the size of 100nm. Also, in the surface characteristic, as a result of measuring the wettability, it could be known that the h-PDMS stamp has the surface characteristic of the hydrophobic and surface energy. The adhesion force and the friction force were very low. In the nanocontact printing of non-planar substrates experiment, a substrate of cylindrical on which the Cr adhesion layer of 100Å and the Au etching layer of 500Å were deposited by using the DC sputter and a substrate of ellipsoidal on which the Ti adhesion layer of 100Å and the Pd etching layer of 500Å were deposited in the form of a thin film, were fabricated, and a pattern was transferred to the substrates where to print by the flexible h-PDMS stamp wet with the SAM solution, and nanostructures had a high resolution without any defect could be fabricated. Also, we are seeking for its applicability to a organic electronic device, flexible electronic display, biological electronic device and the like by optimizing the nanocontact printing process.
Inkjet printing technology has begun to get into the spotlight in many ways due to the superior price competitiveness to existent semi-conductor process. This paper will introduce a newly devised gap adjustable inkjet printing system for dense and high-temperature-melting materials such as metal paste. The design on the gap adjustable inkjet printing system is discussed in detail for precise control of the size and spacing of the injected metal droplets. Analytic optimization and effects of design parameters are examined and computational work using the axis-symmetric, incompressible, multiphase equations is carried out to predict characteristics of the metal paste jetting and to design optimal micro nozzle prototype. From this analysis, droplet trajectory visualization and velocity vector of ejected droplet have been investigated to characterize the relationship between inlet condition and nozzle profile. Finally, the designed gap adjustable inkjet printing system is fabricated and its peformances are tested according to the change of various gap distances and the droplet characteristics are measured in the view point of precise droplet controllability and productivity.
The hybrid nanocontact printing(HnCP) method is a technology for manufacturing an ultra violet(UV) imprinted silicon substrate from a master and then printing by letting it get in contact with a substrate coated with a metal thin film. It comprises a step in which a master with a nano-pattern is prepared; a step in which the resist is applied to the surface of the silicon substrate; an imprinting step in which the master is let to get in contact with the resist surface, pressurized and then taken off; a step in which the imprinted silicone substrate is manufactured into a nanocontact stamp by curing the resist on the imprinted silicon substrate; a step of inking a self-assembled monolayer on the surface of the imprinted silicone substrate stamp; a step of transferring a printing pattern by letting the imprinted silicone substrate stamp get in contact with the substrate coated with a metal thin film; and a step of forming a desired pattern on the substrate by etching the metal thin film on the substrate to which the printing pattern has been transferred. In case the HnCP method, on which this study is conducted, is used, it enables the stamp manufacturing process to be shortened and optimized, because the nanoocontact printing process is conducted by using an imprinted silicon substrate stamp, and it has the advantage of making the stamp have a large area so that it is possible to produce it in a large quantity through a mass production process. Also, as a hard stamp is used, any error resulting from an ultra micro torsion and mismatching can be prevented in the multi-layering process, and since any deformation or defect is not brought about, the pattern's resolution can be enhanced so that it is possible to embody a pattern of 100nm.