• Title/Summary/Keyword: 발광다이오드 칩

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백색 LED 조명 광원제작 공정에 필요한 포토마스크 제작

  • 하수호;최재호;황성원;김근주
    • Proceedings of the Korean Society Of Semiconductor Equipment Technology
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    • 2004.05a
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    • pp.202-206
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    • 2004
  • 본 연구에서는 고밀도로 백색 발광다이오드를 웨이퍼 상에 제작하기 위한 제조공정에 필요한 포토마스크를 제작하는 연구를 수행하였다. 발광다이오드 한 개의 패턴을 웨이퍼상에 연속적으로 배열하여 이를 병렬로 연결하는 금속배선을 고려하였다. AutoCAD의 DWG 파일로 캐드작업을 수행하여 이를 DXF 파일로 변환하였으며, 레이저빔으로 스켄하여 소다라임 유리판 위에 크롬을 식각함으로써 포토마스크를 제작하였다. 이는 기존에 제작된 개별칩 형태의 발광다이오드 제작공정을 집적공정화함으로써 웨이퍼상에서 전면 발광하는 조명광원의 구조를 갖는다. 또한 이를 활용하여 백색 발광다이오드 집적칩을 제작하려 한다.

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Study on the Thermal Dissipation Characteristics of 16-chip LED Package with Chip Size (16칩 LED 패키지에서 칩 크기에 따른 방열특성 연구)

  • Lee, Min-San;Moon, Cheol-Hee
    • Journal of the Korean Vacuum Society
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    • v.21 no.4
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    • pp.185-192
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    • 2012
  • p-n junction temperature and thermal resistance of Light Emitting Diode (LED) package are affected by the chip size due to the change of the thermal density and the external quantum efficiency considering the heat dissipation through conduction. In this study, forward voltage was measured for two different size LED chips, 24 mil and 40 mil, which consist constitute 16-chip package. p-n junction temperature and thermal resistance were determined by thermal transient analysis, which were discussed in connection with the electrical characteristics of the LED chip and the structure of the LED package.

Fabrication of Optical Micro-Encoder Chips for Sub-Micron Displacement Measurements (발광다이오드를 이용한 초정밀 변위 측정용 마이크로 엔코더 칩 제작)

  • Kim, Keun-Joo;Kim, Yun-Goo
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.2 s.95
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    • pp.74-81
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    • 1999
  • The integrated chip of optical micro-encoder was fabricated and the feasibility as displacement measurement device was confirmed. The geometry of micro-encoder was designed to utilize the optical interference effect on the second order of diffracted beams. The hybrid-type micro-encoder consisted with light emitting diode, photodiode, polyimide wave-guide and micro-lens provides stable micro-encoding results for high speed displacements. The measurement shows the resolution of displacement of 1.00 +/- 0.02 ${\mu}m$ for the grating with scale pitch of 2.0${\mu}m$.

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Correlation between the Active-Layer Uniformity and Reliability of Blue Light-Emitting Diodes (청색 발광 다이오드에서 활성층의 균일성과 신뢰성 사이의 상관관계 고찰)

  • Jang Jin-Won;Kim Sang-Bae
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.42 no.12
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    • pp.27-34
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    • 2005
  • We have investigated the correlation between the active-layer uniformity and reliability of InGaN/GaN blue LEDs. According to initial characteristics, the devices are classified into two groups: group I devices of uniform light-emission and group II devices of non-uniform light-emission. The group II devices are more dependent on temperature and we have found two degradation mechanisms through reliability test. One is bulk degradation in which the degradation occurred over the entire chip and another one is edge degradation in which the degradation occurred from the edge of the chip. Bulk degradation caused by the nonradiative defects is found to be faster in group II devices while there is no difference in the rate of the much faster edge degradation, where darkening starts from the n-Ohmic contact edge. Therefore, more uniform active layer, more uniform current spreading, and the passivation of the dry-etched side-wall are essential for the high reliability of InGaN/GaN LEDs.

Process Capability Optimization of Ball Bonding Using Response Surface Analysis in Light Emitting Diode(LED) Wire Bonding (반응 표면 분석법을 이용한 Light Emitting Diode(LED) wire bonding 용 Ball Bonding 공정 최적화에 관한 연구)

  • Kim, Byung-Chan;Ha, Seok-Jae;Yang, Ji-Kyung;Lee, In-Cheol;Kang, Dong-Seong;Han, Bong-Seok;Han, Yu-Jin
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.4
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    • pp.175-182
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    • 2017
  • In light emitting diode (LED) chip packaging, wire bonding is an important process that connects the LED chip on the lead frame pad with the Au wire and enables electrical operation for the next process. The wire bonding process is divided by two types: thermo compression bonding and ultrasonic bonding. Generally, the wire bonding process consists of three steps: 1st ball bonding that bonds the shape of the ball on the LED chip electrode, looping process that hangs the wire toward another connecting part with a loop shape, and 2nd stitch bonding that forms and bonds to another electrode. This study analyzed the factors affecting the LED die bonding processes to optimize the process capability that bonds a small Zener diode chip on the PLCC (plastic-leaded chip-carrier) LED package frame, and then applied response surface analysis. The design of experiment (DOE) was established considering the five factors, three levels, and four responses by analyzing the factors. As a result, the optimal conditions that meet all the response targets can be derived.

Fabrication of Flexible Micro LED for Beauty/Biomedical Applications (미용/의료용 유연 마이크로 발광 다이오드 디바이스 제작 공정)

  • Jae Hee Lee
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.36 no.6
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    • pp.563-569
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    • 2023
  • Micro light-emitting diodes (LEDs), with a chip size of 100 micrometers or less, have attracted significant attention in flexible displays, augmented reality/virtual reality (AR/VR), and bio-medical applications as next-generation light sources due to their outstanding electrical, optical, and mechanical performance. In the realm of bio-medical devices, it is crucial to transfer tiny micro LED chips onto desired flexible substrates with low precision errors, high speed, and high yield for practical applications on various parts of the human body, including someone's face and organs. This paper aims to introduce a fabrication process for flexible micro LED devices and propose micro LED transfer techniques for cosmetic and medical applications. Flexible micro LED technology holds promise for treating skin disorders, cancers, and neurological diseases.

The characteristic of InGaN/GaN MQW LED by different diameter in selective area growth method (선택성장영역 크기에 따른 InGaN/GaN 다중양자우물 청색 MOCVD-발광다이오드 소자의 특성)

  • Bae, Seon-Min;Jeon, Hun-Soo;Lee, Gang-Seok;Jung, Se-Gyo;Yoon, Wi-Il;Kim, Kyoung-Hwa;Yang, Min;Yi, Sam-Nyung;Ahn, Hyung-Soo;Kim, Suck-Whan;Yu, Young-Moon;Ha, Hong-Ju
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.22 no.1
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    • pp.5-10
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    • 2012
  • In general, the fabrications of the LEDs with mesa structure are performed grown by MOCVD method. In order to etch and separate each chips, the LEDs are passed the RIE and scribing processes. The RIE process using plasma dry etching occur some problems such as defects, dislocations and the formation of dangling bond in surface result in decline of device characteristic. The SAG method has attracted considerable interest for the growth of high quality GaN epi layer on the sapphire substrate. In this paper, the SAG method was introduced for simplification and fabrication of the high quality epi layer. And we report that the size of selective area do not affect the characteristics of original LED. The diameter of SAG circle patterns were choose as 2500, 1000, 350, and 200 ${\mu}m$. The SAG-LEDs were measured to obtain the device characteristics using by SEM, EL and I-V. The main emission peaks of 2500, 1000, 350, and 200 ${\mu}m$ were 485, 480, 450, and 445 nm respectively. The chips of 350, 200 ${\mu}m$ diameter were observed non-uniform surface and resistance was higher than original LED, however, the chips of 2500, 1000 ${\mu}m$ diameter had uniform surface and current-voltage characteristics were better than small sizes. Therefore, we suggest that the suitable diameter which do not affect the characteristic of original LED is more than 1000 ${\mu}m$.

Influence of Blue-Emission Peak Wavelength on the Reliability of LED Device (청색 피크 파장이 LED 소자에 미치는 영향)

  • Han, S.H.;Kim, Y.J.;Kim, J.H.;Jung, J.Y.;Kim, H.C.;Cho, G.S.
    • Journal of the Korean Vacuum Society
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    • v.21 no.3
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    • pp.164-170
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    • 2012
  • The dependance of degradation on the blue-peak wavelength is investigated with the blue light-emitting diode (LED) of InGaN/GaN with respect to the optical and the electrical characteristics of the devices. The LED devices emitting the blue-peak wavelength ranging from 437 nm to 452 nm is prepared to be stressed for a long aging time with three different currents of 60 mA, 75 mA and 90 mA, respectively. The degradation of optical intensity is observed with and without phosphor in the devices. The device without phosphor has been degraded significantly as the wavelength of blue-peak is decreased while the optical intensity of LED device with phosphor become less sensitive than that of device without phosphor. The electrical property does not depend on the emission peak wavelength. However, the series-resistance of LED device is slowly increased as the aging time is increased. The deformation of device is observed severely the short wavelength of blue-peak even with the same current since the short wavelength is absorbed substantially at the materials of device during the aging time. Consequently, in order to enhance the lifetime of LED devices, it is important to understand the optical degradation property of the materials against the specific wavelengths emitted from the blue chip.

고방열 세라믹 기판을 이용한 LED 방열 특성에 대한 고찰

  • Kim, Min-Seon;Jo, Hyeon-Min;Go, Sang-Gi;Jang, Min-Gyeong;Lee, Geon-Hyeong
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.08a
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    • pp.127-127
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    • 2010
  • 최근 Light-emitting diodes (LEDs: 발광다이오드) 디바이스의 고휘도, 저전력, 긴 수명, 다양한 색연출 가능, 친환경 소자 등의 장점으로 LED 디바이스가 flat panel display(FPD)의 back light unit (BLU) 를 비롯해 실내 외 조명과 자동차 전조등 분야 이외에도 의료, 인테리어 사업을 비롯한 각종 전자 통신 기기의 정보 처리 기기의 표시소자 등, 여러 제품 군에 적용되는 가운데 큰 관심을 받고 있다. 하지만 이러한 여러 가지 장점에도 불구하고 LED 모듈에서의 junction temperature가 높은 방열 특성이 나쁘다는 단점은 아직 해결되지 않고 있는 실정이다. LED 소자 모듈에서의 junction temperature가 높을 경우 소비되는 에너지가 많을 뿐만 아니라 LED 소자의 발광효율이 떨어지고 수명이 급격히 저하 되어, 결국에는 신뢰성 특성이 현저히 저하 되는 결과가 초래되기 때문이다. 따라서 본 논문에서는 LED 디바이스의 열저항을 낮추기 위해 고방열 세라믹 기판을 이용해 LED 디바이스의 방열 특성을 향상시킨 결과를 제시한다. 고방열 세라믹 기판을 제작하여 LED 칩을 실장시킨 다음 LED 열저항 특성을 측정하였다. 이때 고방열 세라믹 기판은 Al2O3와 AlN이 사용되었으며 제작한 세라믹 기판의 강도, 표면 roughness, 미세구조 등을 살펴보고 이 기판들의 열전도도를 측정하였다. 제작 공정방법에 따라 세라믹 기판의 미세구조를 비롯한 기계적, 열적 특성이 현저히 변하였으며 이때 LED 칩을 실장 하여 측정한 열저항 특성 값도 함께 변하였다. Al2O3의 열저항 값은 3.003 K/W 으로 측정 되었으며, AlN의 열저항 값은 3.003k/W 으로 측정되었다.

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Performance Investigation of Visible Light Communication Using Super Bright White LED and Fresnel Lens (조명용 고출력 백색 LED와 프레넬 렌즈를 이용한 가시광 통신 성능연구)

  • Kim, Min-Soo;Sohn, Kyung-Rak
    • Journal of Advanced Marine Engineering and Technology
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    • v.39 no.1
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    • pp.63-67
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    • 2015
  • White light-emitting diode (WLED) is growing interest in using both illumination and communications. This paper reports visible light communication (VLC) composed of a super bright white light-emitting diode, low cost commercial photo-diode and a Fresnel lens. LED driver is consisted of the power MOSFET and MOSFET driver that switches the LED on and off. The modulation bandwidth of the LED used was determined to be 8 MHz. However, it was possible to communicate up to 1 Mbps under illumination of 500 lx because of the weak signal power and a low spectral sensitivity of the SHF213 as a PIN photodiode. In order to enhance the system bandwidth, the LED light was focused on the PIN photodiode by use of the Fresnel lens. As a result of that, visible light link was operated up to modulation bandwidth of the LED. The signal to noise ratio can be improved by 40 dB using an optical concentration at the receiver.