• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1553-1555
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• 2008

Super-hydrophobic treated Polyimide film was used as a flexible substrate for developing a new method of metallization. Hydrophilic patterns were fabricated by IN irradiation through shadow mask. Patterned super-hydrophobic substrate was dipped into a bath containing silver nano ink Silver ink was only coated on hydrophilic patterned area. Metal lines of $600{\mu}m$ pitch were fabricated successfully. However, their thickness was too thin to serve as interconnection. To overcome this problem, iterative dipping was conducted. After repeating five times, the thickness of silver metal lines were increased to over than $2{\mu}$. After heat treatment of silver lines, their resistivities were reduced to order of $30{\mu}{\Omega}$-cm the similar level of values reported in other literatures. So, a new method of metallization has high potential for application of RFID antenna and flexible electronics substrates.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.3
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• pp.408-414
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• 2012

Screen printing is a printing method that uses a woven mesh to support an ink-blocking stencil by transferring ink or other printable materials in order to form an image onto a substrate. Recently, the screen printing method has applied to micro-electronic packaging by using solder paste as a printable material. For the screen printing of solder paste, metal masks containing a number of micro-holes are used as a stencil material. The metal mask undergoes deformation when it is installed in the screen printing machine, which results in the deformation of micro-holes. In the present study, finite element (FE) analysis was performed to predict the amount of deformation of a metal mask. For an efficient calculation of the micro-holes of the metal mask, the sub-domain analysis method was applied to perform FE analyses connecting the global domain (the metal mask) and the local domain (micro-holes). The FE analyses were then performed to evaluate the effects of slot designs on the deformation characteristics, from which more uniform and adjustable deformation of the metal mask can be obtained.

• Proceedings of the KIEE Conference
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• 2007.11a
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• pp.98-99
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• 2007

This study has successfully demonstrated the direct fabrication of polymer resistors using ink-jet printing technology as an alternative patterning to traditional photolithography. The polymer resistors were fabricated just by two layer processes using a ink-jet printer (DMP-2800, Fujifilm Dimatix). First, resistive materials was patterned by a ink-jet printing with the desired width and length. Next, resistor fabrication was completed by printing metal contact pads on the both sides of the polymer resistor. We used poly (3,4-ethylene dioxythiophene) poly(styrenesulfonate)(PEDOT:PSS) for the resistor material and a nano-sized silver colloid for the metal contact pads. We characterized the electrical properties of PEDOT:PSS by measuring sheet resistance and specific resistance on a glass substrate. From analysis of the measured resistances, the electrical resistances of the polymer resistors linearly increased as a function of printed width and length of resistors. The accuracy of the fabricated polymer resistor showed about $0.6{\sim}2.5%$ error for the same dimensions.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.5
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• pp.454-462
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• 2023

Flash lamp annealing (FLA) of metal nanoparticle (NP) ink has provided powerful strategies to fabricate high-performance electrodes on a flexible substrate because of its rapid processing capability (in milliseconds), low-temperature process, and compatibility with to roll-to-roll process. However, metal NPs [e.g., gold (Au), silver (Ag), copper (Cu), etc.] have limitations such as difficulty in synthesizing fine metal NPs (diameter less than 10 nm), high price, and degradation during ink storage and FLA processing. In this regard, organometallic ink has been proposed as a material that can replace metal NPs due to their low-cost (usually 1/100 times cheaper than metal nano inks), low-temperature processability, and high material stability. Despite these advantages, the fabrication of flexible electrodes through FLA treatment of organometallic compounds has not been extensively researched. In this paper, we experimentally guide how to determine the optimal conditions for forming electrodes on flexible substrates by considering material parameters, and flashlight processing parameters (energy density, pulse duration, etc) to minimize the difficulties that may arise during the FLA of organometallic ink.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.2
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• pp.97-103
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• 2008

In this investigation, conductivity of conductive inks was measured. A particular attention has been given to the effect of metal powders with various conductivity on the overall conductivity of the bulk ink. The conductivity of various solutions simulating conductive inks consisting of copper and silver was measured and the results have been discussed in relation to various applications of conductive inks in practice. A conductivity model simulating systems consisting of various materials has been introduced and the results were discussed. Materials of good conductivity are adversely affected by mixing with materials of poor conductivity simply through serial connection. However, parallel connection has rather little effect on the overall conductivity. The practical implication of various mixtures of materials on conductive inks has been discussed.

• Journal of the Semiconductor & Display Technology
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• v.10 no.2
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• pp.73-81
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• 2011

We manufactured the inkjet printing system for the application into the nano Ag finger line interconnection process in Si solar cells. The home-made inkjet printer consists of motion part for XY motion stage with optical table, head part, power and control part in the rack box with pump, and ink supply part for the connection of pump-tube-sub ink tanknozzle. The ink jet printing system has been used to conduct the interconnection process of finger lines on Si solar cell. The nano ink includes the 50 nm-diameter. Ag nano particles and the viscosity is 14.4 cP at $22^{\circ}C$. After processing of inkjet printing on the finger lines of Si solar cell, the nano particles were measured by scanning electron microscope. After the heat treatment at $850^{\circ}C$, the finger lines showed the smooth surface morphology without micropores.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.730-732
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• 2007

We fabricated a coplanar type organic thin-film transistors using ink-jet printed silver source/drain electrodes and ${\alpha},{\omega}-dihexylquaterthiophene$ (DH4T) which is an active layer. Use of ink-jet printed silver nanoparticle-based metal electrode assists the energetic mismatch with p-type organic semiconductor via modification of their interfacial properties to enable ohmic contact formation.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.1
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• pp.126-131
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• 2008

In this investigation, various factors affecting manufacturing conductive inks are presented, examined and discussed. The discussion includes inherent difficulties in making conductive inks successful and at the same time offers ways in which these difficulties might be overcome. One of the solutions to overcome such difficulties is to use low melting metals and alloys. This aspect is also detailed.

• Journal of the Korean Graphic Arts Communication Society
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• v.9 no.1
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• pp.45-51
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• 1991

Commercially available paper stickers, electrostatic stickers, and metal sticker generally involve process of printing on the substrate and die-cutting to peel the sticker off the release paper. Using plastisol ink and multi-layer screen printing technique, a process of non die-cutting sticker with same image on both sides was developed. It was also possible to prevent color mixing phenomena at image edge part by printing narrow lines of black ink along the borderline.

• Journal of ILASS-Korea
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• v.17 no.1
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• pp.20-26
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• 2012

Inkjet printing is one of the direct writing technologies and is able to form a pattern onto substrate by dispensing droplets in desired position. Also, by inkjet technology manufacturing time and production costs can be reduced, and procedures can be more efficient. To form a metal pattern, it must be harmonized with conductive nano ink, printing process, sintering, and surface treatment. In this study, micro patterning of conductive line has been investigated using the piezoelectric printhead driven by a bipolar voltage signal is used to dispense $20-40{\mu}m$ diameter droplets and silver nano ink which consists of 50 nm silver particles. In addition, hydrophobic treatment of surface, overlap printing techniques, and sintering conditions with changing temperature and times to achieve higher conductivity.