• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2007.06a
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• pp.164-168
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• 2007

Deformation of a shadow mask is one of the problems encountered during the deposition of organic materials for manufacturing large size OLED. The larger the glass substrate, the larger the shadow mask becomes. But as the size of the shadow mask increases, its deformation becomes more severe, thereby making it difficult to deposit organic materials in a precise pattern on a substrate. In this paper, a new type mask-frame structure is proposed. The proposed mask-frame structure making a curved mask has the ability of reducing drooping of mask. The test frame is fabricated and evaluation experiments are performed.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.411-413
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• 2003

When manufacturing large sized OLED devices, the evaporation source is the most important technology. The nozzle source maintains the uniformity of the large-size deposited organic thin film at the 2-3% level and its usage is only 0.8 gram/hour. The in-line manufacturing deposition system combining with an encapsulation system is proposed.

• Journal of the Semiconductor & Display Technology
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• v.11 no.1
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• pp.49-54
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• 2012

There have been plenty of difficulties because properties of Alq3 are unable to acquire in a process of manufacture of OLED. In this paper it will predict a viscosity of Alq3 through DSMC technique and suggest the way regarding a study to estimate properties of material through the computer simulation. There could generate errors of a simulation process in a vacuum deposition process since the properties of material that is used in a high-degree vacuum environment are not secured. Therefore, we would like to propose the new methods that can not only predict properties of a molecular unit but also raise an accuracy of simulation process by forecasting properties of Alq3.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.742-745
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• 2004

A profitable mass production of Organic Light Emitting Diode (OLED) displays needs a new type of manufacturing equipment. We have developed a vertical In-Line machine (VES400) equipped with linear etch sources (e.g. to activate an ITO layer), standard magnetron sputter sources for ITO and metal and linear evaporation sources for the organic and metal materials. We present new results concerning the linear evaporation sources for organic materials. We have optimized the vertical thickness non uniformity for the evaporation of different organic materials and achieved deviations of less than ${\pm}$ 5 % for the vertical thickness over a substrate height of 400 mm. We will further report first results about the long term stability of the deposition rate for different organic materials using rate control..

• Journal of Sensor Science and Technology
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• v.28 no.6
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• pp.402-406
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• 2019

Recently, semiconducting organic materials have been spotlighted as next-generation electronic materials based on their tunable electrical and optical properties, low-cost process, and flexibility. However, typical organic semiconductor materials are vulnerable to moisture and oxygen. Therefore, an encapsulation layer is essential for application of electronic devices. In this study, SiN_x thin films deposited at process temperatures below 150 ℃ by plasma-enhanced chemical vapor deposition (PECVD) were characterized for application as an encapsulation layer on organic devices. A single structured SiN_x thin film was optimized as an organic light-emitting diode (OLED) encapsulation layer at process temperature of 80 ℃. The optimized SiN_x film exhibited excellent water vapor transmission rate (WVTR) of less than 5 × 10^-5 g/㎡·day and transmittance of over 87.3% on the visible region with thickness of 1 ㎛. Application of the SiN_x thin film on the top-emitting OLED showed that the PECVD process did not degrade the electrical properties of the device, and the OLED with SiN_x exhibited improved operating lifetime

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.5
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• pp.397-402
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• 2010

In this paper, we studied WVTR(water vapor transmission rate) properties of $Si_3N_4$ thin film that was deposited using TCP-CVD (transformer coupled plasma chemical vapor deposition) method for the possibility of OLED(organic light emitting diode) encapsulation. Considering the conventional OLED processing temperature limit of below $80^{\circ}C$, the $Si_3N_4$ thin films were deposited at room temperature. The $Si_3N_4$ thin films were prepared with the process conditions: $SiH_4$ and $N_2$, as reactive gases; working pressure below 15 mTorr; RF power for TCP below 500 W. Through MOCON test for WVTR, we analyzed water vapor permeation per day. We obtained that WVTR property below 6~0.05 gm/$m^2$/day at process conditions. The best preparation condition for $Si_3N_4$ thin film to get the best WVTR property of 0.05 gm/$m^2$/day were $SiH_4:N_2$ gas flow rate of 10:200 sccm, working pressure of 10 mTorr, working distance of 70 mm, TCP power of 500 W and film thickness of 200 nm. respectively. The proposed results indicates that the $Si_3N_4$ thin film could replace metal or glass as encapsulation for flexible OLED.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.397.2-397.2
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• 2014

유기 발광 다이오드 (OLED)의 상용화를 위해 해결해야할 기술적 문제 중하나는 장수명이다. OLED에 적용된 유기물 층은 수분과 산소에 취약하여 소자 수명을 단축하는 요소로 작용하는데, 이를 해결하기 위해 유기물을 보호하며, 유기물 내로 침투되는 수분과 산소를 제어하기 위한 보호 층의 증착이 필수적이다. 필수적이다. 본 연구에서는, 사이클 화학 기상 증착법(C-CVD)을 이용하여 SiN/SiCN/SiN 구조의 무기 박막을 증착하여 유기물 보호층으로서의 적용 가능성을 제시하고자 한다. 이 때 각층의 두께는 각 각 10 nm이다. 증착된 다층 무기 박막은 비정질 상으로 수분 침투 보호막으로서 적당하다. 다층 무기 박막의 수분에 대한 저항성은 칼슘을 이용한 투과도 변화를 이용하여 측정하였다. 칼슘을 이용한 투과도 측정을 위해 고분자 PEN 필름위에 칼슘을 60nm 두께로 증착 시키고, 이어서 무기물인 SiN/SiCN/SiN의 다층 박막을 확산 방지층으로 증착 하였다. 제작된 소자는 온도 $85^{\circ}C$, 상대습도 85%의 가혹 조건에서 시간에 따른 표면 변화 및 투과도의 변화를 측정하였다. SiN/SiCN/SiN 구조를 갖는 무기 박막 층의 투습도는 3000시간까지는 $3.2{\times}10-5g/m/day$를 유지하였다. 이는 OLED 소자의 상용화를 위한 요구 조건에 근접한 값이다. 그러나 투습도는 측정 시간이 6000시간이 지난 후에 급격 증가하는데 이것은 30nm 두께의 SiN/SiCN/SiN의 확산 방지층에 임계 수명이 존재 한다는 것을 의미 한다고 할 수 있다. C-CVD 기술에 의해 제조된 다층 무기 박막 보호 층의 경계면에서 각 층간의 intermixing 현상이 관측되었으며, 이는 무기물 층의 결함과 핀 홀을 통해 내부로 확산 되는 수분의 침투 경로를 효과적으로 제어할 수 있는 방법이다. 본 연구 결과는 유연 기판 상에 제작된 OLED 소자에 적용 가능한 기술로서 소자 수명의 연장 뿐만 아니라 경량화에도 기여할 수 있는 기술이다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.450-450
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• 2006

Organic light-emitting diodes (OLED) as pixels for flat panel displays are being actively pursued because of their relatively simple structure, high brightness, and self-emitting nature [1, 2]. The top-emitting diode structure is preferred because of their geometrical advantage allowing high pixel resolution [3]. To enhance the performance of TOLEDs, it is important to deposit transparent top cathode films, such as transparent conducting oxides (TCOs), which have high transparency as well as low resistance. In this work, we report on investigation of the characteristics of an indium tin oxide (ITO) cathode electrode, which was deposited on organic films by using a radio-frequency magnetron sputtering method, for use in top-emitting organic light emitting diodes (TOLED). The cathode electrode composed of a very thin layer of Mg-Ag and an overlaying ITO film. The Mg-Ag reduces the contact resistivity and plasma damage to the underlying organic layer during the ITO sputtering process. Transfer length method (TLM) patterns were defined by the standard shadow mask for measuring specific contact resistances. The spacing between the TLM pads varied from 30 to $75\;{\mu}m$. The electrical properties of ITO as a function of the deposition and annealing conditions were investigated. The surface roughness as a function of the plasma conditions was determined by Atomic Force Microscopes (AFM).

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.380-380
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• 2010

Currently, organic light-emitting diodes (OLEDs) have been proven of their readiness for commercialization in terms of lifetime and efficiency. In accordance with emerging new technologies, enhancement of light efficiency and extension of application fields are required. Particularly inverted structures, in which electron injection occurs at bottom and hole injection on top, show crucial advantages due to their easy integration with Si-based driving circuits for active matrix OLED as well as large open area for brighter illumination. In order to get better performance and process reliability, usually a proper buffer layer for carrier injection is needed. In inverted top emission OLED, the buffer layer should protect underlying organic materials against destructive particles during the electrode deposition, in addition to increasing their efficiency by reducing carrier injection barrier. For hole injection layers, there are several requirements for the buffer layer, such as high transparency, high work function, and reasonable electrical conductivity. As a buffer material, a few kinds of transition metal oxides for inverted OLED applications have been successfully utilized aiming at efficient hole injection properties. Among them, we chose 2 nm of $WO_3$ between NPB [N,N'-bis(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine] and Au (or Al) films. The interfacial energy-level alignment and chemical reaction as a function of film coverage have been measured by using in-situ ultraviolet and X-ray photoelectron spectroscopy. It turned out that the $WO_3$ interlayer substantially reduces the hole injection barrier irrespective of the kind of electrode metals. It also avoids direct chemical interaction between NPB and metal atoms. This observation clearly validates the use of $WO_3$ interlayer as hole injection for inverted OLED applications.

• Journal of Mechanical Science and Technology
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• v.18 no.9
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• pp.1680-1688
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• 2004

The information indicating device plays an important part in the information times. Recently, the classical CRT (Cathod Ray Tube) display is getting transferred to the LCD (Liquid Crystal Display) one which is a kind of the FPDs (Flat Panel Displays). The OLED (Organic Light Emitting Diodes) display of the FPDs has many advantages for the low power consumption, the luminescence in itself, the light weight, the thin thickness, the wide view angle, the fast response and so on as compared with the LCD one. The OLED has lately attracted considerable attention as the next generation device for the information indicators. And also it has already been applied for the outside panel of a mobile phone, and its demand will be gradually increased in the various fields. It is manufactured by the vapor deposition method in the vacuum state, and the uniformity of thin film on the substrate depends on the temperature distribution in the point-cell source. This paper describes the basic concepts that are obtained to design the point-cell source using the computational temperature analysis. The grids are generated using the module of AUTOHEXA in the ICEM CFD program and the temperature distributions are numerically obtained using the STAR-CD program. The temperature profiles are calculated for four cases, i.e., the charge rate for the source in the crucible, the ratio of diameter to height of the crucible, the ratio of interval to height of the heating bands, and the geometry modification for the basic crucible. As a result, the blowout phenomenon can be shown when the charge rate for the source increases. The temperature variation in the radial direction is decreased as the ratio of diameter to height is decreased and it is suggested that the thin film thickness can be uniformed. In case of using one heating band, the blowout can be shown as the higher temperature distribution in the center part of the source, and the clogging can appear in the top end of the crucible in the lower temperature. The phenomena of both the blowout and the clogging in the modified crucible with the nozzle-diffuser can be prevented because the temperature in the upper part of the crucible is higher than that of other parts and the temperature variation in the radial direction becomes small.