• Journal of the Korean Society for Precision Engineering
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• v.31 no.6
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• pp.477-481
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• 2014

Flexible electronics have been to the fore because it is believed that flexibility can add incredible value such as light weight and mobility into the existing electronic devices and create new markets of large-area and low-cost electronics such as wearable eletronics in near future. Offset printing processes are regarded as major candidates for manufacturing the flexible electronics because they can provide the patterning resolution of micron-size effectively in large-area. In view of mechanics, the most important viewpoint in offset printing is how to achieve the synchronized movement of two contact surfaces in order to prevent slip between two contact surfaces and distortion of the blanket surface during ink transfer so that the high-resolution and good-overlay patterns can be printed. In this paper, a novel low-cost measurement method of the synchronization error using the motor control output signals is proposed and the compensation method is presented to minimize the synchronization error.

• Journal of Powder Materials
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• v.31 no.2
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• pp.169-179
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• 2024

Colloidal quantum dot (QDs) have emerged as a crucial building block for LEDs due to their size-tunable emission wavelength, narrow spectral line width, and high quantum efficiency. Tremendous efforts have been dedicated to improving the performance of quantum dot light-emitting diodes (QLEDs) in the past decade, primarily focusing on optimization of device architectures and synthetic procedures for high quality QDs. However, despite these efforts, the commercialization of QLEDs has yet to be realized due to the absence of suitable large-scale patterning technologies for high-resolution devices., This review will focus on the development trends associated with transfer printing, photolithography, and inkjet printing, and aims to provide a brief overview of the fabricated QLED devices. The advancement of various quantum dot patterning methods will lead to the development of not only QLED devices but also solar cells, quantum communication, and quantum computers.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.9
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• pp.873-877
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• 2013

The application of inkjet technology has been broadening from home printers to manufacturing tools. Recently, there have been demands for high-resolution printing, especially in the field of printed electronics applications. To improve upon the conventional inkjet printing patterning method, electrohydrodynamic (EHD) inkjet technology has recently attracted attention because droplets smaller than the nozzle diameter can be ejected and materials with wider viscosity range can be used for jetting. In this study, an EHD jet printing system for fine patterning is presented. To print various patterns based on drop on demand printing, vector and raster printing algorithm are implanted in the printing software. Fine conductive patterns with line width of less than $7{\mu}m$ can be easily achieved via EHD jet using a nozzle with inner diameter of $8{\mu}m$.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.564-566
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• 2007

Synthesis of two photoactive compounds containing core imide moiety was carried out for an application to interdielectric layer in TFTLCD array. An aqueous alkaline developable polymer matrix was synthesized by free radical copolymerization. A positive photoresist formulation was developed utilizing synthesized UV monomers, photoactive compound, binder polymer, sulfactant and alkali developable polymer matrix. It was found that via-holes with good resolution, high transmittance and thermal resistance could be obtained by photolithographic process utilizing the new positive interdielectric material with high thermal stability.

• Korean Journal of Materials Research
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• v.11 no.6
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• pp.527-532
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• 2001

Dry etching of copper film using $O_2$ plasma and H(hfac) has been investigated. A one-step process consisting of copper film oxidation with an $O_2$ plasma and the removal of surface copper oxide by the reaction with H(hfac) to form volatile Cu(hfac)$_2$ and $H_2O$ was carried but. The etching rate of Cu in the range from 50 to 700 /min was obtained depending on the substrate temperature, the H(hfac)/O$_2$ flow rate ratio, and the plasma power. The copper film etch rate increased with increasing RF power at the temperatures higher than 215$^{\circ}C$. The optimum H(hfac)/O$_2$ flow rate ratio was 1:1, suggesting that the oxidation process and the reaction with H(hfac) should be in balance. Cu patterning using a Ti mask was performed at a flow rate ratio of 1:1 on 25$0^{\circ}C$\ulcorner and an isotropic etching profile with a taper slope of 30$^{\circ}$was obtained. Cu dry patterning with a tapered angle which is necessary for the advanced high resolution large area thin film transistor liquid-crystal displays was thus successfully obtained from one step process by manipulating the substrate temperature, RF power, and flow rate ratio.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.32-32
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• 2009

Silicon carbide (SiC) is a wide-bandgap semiconductor that has materials properties necessary for the high-power, high-frequency, high-temperature, and radiation-hard condition applications, where silicon devices cannot perform. SiC is also the only compound semiconductor material. on which a silicon oxide layer can be thermally grown, and therefore may fabrication processes used in Si-based technology can be adapted to SiC. So far, atomic force microscopy (AFM) has been extensively used to study the surface charges, dielectric constants and electrical potential distribution as well as topography in silicon-based device structures, whereas it has rarely been applied to SiC-based structures. In this work, we investigated that the local oxide growth on SiC under various conditions and demonstrated that an increased (up to ~100 nN) tip loading force (LF) on highly-doped SiC can lead a direct oxide growth (up to few tens of nm) on 4H-SiC. In addition, the surface potential and topography distributions of nano-scale patterned structures on SiC were measured at a nanometer-scale resolution using a scanning kelvin probe force microscopy (SKPM) with a non-contact mode AFM. The measured results were calibrated using a Pt-coated tip. It is assumed that the atomically resolved surface potential difference does not originate from the intrinsic work function of the materials but reflects the local electron density on the surface. It was found that the work function of the nano-scale patterned on SiC was higher than that of original SiC surface. The results confirm the concept of the work function and the barrier heights of oxide structures/SiC structures.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.154-154
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• 2006

Samsung Electro Mechanics ink jet has developed ultra high resolution alignment system. The alignment system has been developed for repeatable printing of conductive ink. The resolution of alignment system is 0.5um and the velocity of printing working plate is 1.5m/s. So far repeated printing results included sintering process have over 30um of drop mislocation data. In order to improve line thickness and conductivity of metal line, we need to develop the higher mechanical accurate align system. On the demand, this developed align system has under $1{\sim}2{\mu}m$ mispositioning performance and can measure of mechanical accuracy of inkjet printer, as well as the straightness of jetted drop from inkjet head. There is no kinds limit of substrate and ink to use SEM alignment system. By using this alignment system, we progress two experiment of reiterate printing drop and making conductive line on the glass and photo paper. Optical microscope and 3D profiler has been used for measurement of printed ink.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.369-369
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• 2012

The present work deals with selective deposition of copper on fluoropolymers patterned silicon (111) surfaces. The pattern of fluoropolymer was fabricated by nanoimprint lithography (NIL) and plasma reactive ion etching (RIE) was used to remove the residuals layers. Copper was electrochemically deposited in bare Si regions which were not covered with fluoropolymers. The patterns of fluoropolymers and copper have been investigated by scanning electron microscopy (SEM). In this work, we used two deposition methods. One is galvanic displacement method and another is electrodeposition. Selective deposition works in both cases and it shows applicability to other materials. By optimization of the deposition conditions can be achieved therefore this process represents a simple approach for a direct high resolution patterning of silicon surfaces.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1437-1440
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• 2008

In this paper, we mainly deal with metallic electrode materials and patterning processing of plasma display panels. We focus on the recent development status, where low cost and high performance electrode materials such as Ag-based single-layered bus, low cost-in-use and anti-migration address electrodes are briefly introduced. The technological trends and further works on novel electrode materials and processing are also discussed.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.543-544
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• 2008

Nowadays, the research on the system integration using various technologies, like MCM-C, MCM-L and MCM-D. Especially, MCM-D technology is suitable for mmwave application due to its high resolution of patterning and thermal property similar to that of semiconductor devices. In this work, integrated passive devices like inductor, capacitor and resistor are evaluated on the GaAs substrate and their characteristics are examined. And finally, the Wilkinson power divider using lumped IPD are evaluated on GaAs substrate and it shows low insertion loss below 0.5 dB and the isolation over 15 dB.