LED 모듈의 초고속 레이저 절단을 위한 연구

최원용,좌성훈,Choi, Won Yong,Choa, Sung-Hoon 한국마이크로전자및패키징학회 2017 마이크로전자 및 패키징학회지 Vol.24 No.1

최근 레이저를 이용하여 전자 소자 및 모듈을 절단하기 위한 많은 연구가 진행되고 있다. 본 연구에서는 레이저를 이용하여 LED 모듈을 초고속 절단하기 위한 기초 연구를 수행하였다. 특히 기존의 다이싱(dicing) saw의 절단 속도를 훨씬 능가하는 100 mm/s의 초고속 레이저 절단의 가능성을 검토하였다. 이를 위하여 LED 모듈의 구성 재료인 copper/ceramic 및 silicone/ceramic 이종 복합 기판을 제작하여 레이저 절단 후, 절단면의 표면 특성, 표면조도, 굽힘 강도를 다이싱 saw를 이용하여 절단한 샘플과 비교하였다. 복합 기판에 대한 최적의 레이저 절단 조건을 찾기 위하여, 세라믹 및 구리 단일 기판의 레이저 절단을 통하여 다양한 레이저 공정 조건들에 대한 영향 검토하였다. 절단면의 표면 특성이 가장 좋은 최적의 레이저 절단 조건은 Ar 보조 가스의 사용, 높은 레이저 파워 및 높은 보조 가스의 압력이었다. Copper/ceramic 및 silicone/ceramic 이종 복합 기판에 대하여 레이저 절단과 다이싱 saw로 절단한 기판의 절단면을 비교한 결과, 레이저로 절단된 기판이 다이싱 saw 절단에 비하여 표면이 거칠고 표면 특성이 약간 나쁘다. 레이저 절단면의 평균 표면조도는 약 $9{\mu}m$ 이며, 다이싱 saw로 절단된 절단면의 표면조도는 약 $4{\mu}m$ 이었다. 그러나 다이싱 절단의 절단 속도(3 mm/s)를 고려하면 레이저 절단면의 표면 morphology가 비교적 균일하고, 표면조도도 다이싱 절단의 경우와 큰 차이가 없기 때문에 어느 정도 만족할 만한 결과를 얻었다고 판단된다. 또한 레이저 절단된 기판의 굽힘 강도가 다이싱으로 절단된 기판의 굽힘 강도보다 동등하거나 약간 열세이었다. 그러나 향후 레이저의 절단 조건이 좀 더 최적화된다면 LED 모듈의 초고속 레이저 절단이 가능할 것으로 판단된다. In this study, we conducted the preliminary research for high speed laser cutting of LED module. In particular, the feasibility of ultra-high speed laser cutting of 100 mm/s which exceeds the cutting speed of conventional dicing saw was examined. For this, copper/ceramic and silicone/ceramic hybrid substrates, which are the components of the LED module, were fabricated, and the surface morphology, surface roughness and flexural strength of the laser-cut samples were investigate and compared with the dicing-cut samples. To investigate optimal laser cutting conditions for hybrid substrates, the effects of various laser cutting conditions on cutting surface characteristics were studied using single ceramic and copper substrate. Optimal laser cutting conditions of the hybrid substrates were the use of Ar assist gas, high laser power and high assist gas pressure. Comparing the cutting surface of the hybrid substrates, the surface characteristics of the laser-cut samples are slightly inferior to those of the dicing-cut samples. The average surface roughness of the laser-cut samples was about $9{\mu}m$, and that of the dicing-cut samples was about $4{\mu}m$. However, considering very low cutting speed (3 mm/s) of the dicing saw, the surface morphology of the laser-cut sample was relatively uniform, and the surface roughness was not much different from that of the dicing-cut sample. The flexural strength of the laser-cut samples was equivalent to or slightly inferior to the flexural strength of dicing-cut samples. However, if the laser processing conditions are sufficiently optimized, the ultra-high speed laser cutting of the LED module will be possible.

유연기판을 위한 UV/Thermal 하이브리드방식 나노임프린트 시스템

임형준(HyungJun Lim),이재종(JaeJong Lee),최기봉(Kee-Bong Choi),김기홍(GeeHong Kim),안현진(HyunJin Ahn),류지형(JiHyeong Ryu) 한국생산제조학회 2011 한국생산제조시스템학회 학술발표대회 논문집 Vol.2011 No.4

An UV/thermal hybrid nanoimprint lithography system was designed and implemented for the pattern transfer to flexible substrates. This system can utilize a plate stamp, roll stamp, and film stamp. For all cases of using those stamps, this system is also switchable an UV or thermal nanoimprint lithography mode. This paper shows how to design the heating and UV curing plates and proposes how to change them easily. Because the pressure condition and the speed of the press roller varies by the characteristics of the stamp and substrate, all the parameters related to the nanoimprint lithography have to adjustable. Some transferred patterns are shown in this paper to verify the performance of the hybrid nanoimprint lithography system. The flexible substrates with nano-scale patterns on them will be key components for next generation technologies such as flexible displays, bendable semi-conductors, and solar cells

유연기판을 위한 UV/Thermal 하이브리드방식 나노임프린트 시스템

임형준(Hyung-Jun Lim),이재종(Jae-Jong Lee),최기봉(Kee-Bong Choi),김기홍(Gee-Hong Kim),안현진(Hyun-Jin Ahn),류지형(Ji-Hyeong Ryu) 한국생산제조학회 2011 한국생산제조학회지 Vol.20 No.3

An UV/thermal hybrid nanoimprint lithography system was designed and implemented for the pattern transfer to flexible substrates. This system can utilize a plate stamp, roll stamp, and film stamp. For all cases of using those stamps, this system is also switchable an UV or thermal nanoimprint lithography mode. This paper shows how to design the heating and UV curing plates and proposes how to change them easily. Because the pressure condition and the speed of the press roller varies by the characteristics of the stamp and substrate, all the parameters related to the nanoimprint lithography have to adjustable. Some transferred patterns are shown in this paper to verify the performance of the hybrid nanoimprint lithography system. The flexible substrates with nano-scale patterns on them will be key components for next generation technologies such as flexible displays, bendable semi-conductors, and solar cells.

Flexible p-type PEDOT:PSS/a-Si:H hybrid thin film solar cells with boron-doped interlayer

Lee, Yoo Jeong,Yeon, Changbong,Lim, Jung Wook,Yun, Sun Jin Elsevier 2018 SOLAR ENERGY -PHOENIX ARIZONA THEN NEW YORK- Vol.163 No.-

<P><B>Abstract</B></P> <P>We reported highly flexible a-Si:H thin film solar cells with p-type poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) window. We firstly adopted the substrate-type cell structure on 75 μm-thick polyimide (PI) film unlike earlier studies in which the superstrate-type cell structures were utilized and the deformation of PEDOT:PSS was inevitably caused by subsequent deposition processes. We clearly demonstrated that the performance of the hybrid a-Si:H thin film solar cells with the substrate-type structure was superior to that of the superstrate-type cells. A highly boron-doped interlayer (IL) of 5 nm thickness was introduced at the hetero-interface between the p-type PEDOT:PSS and intrinsic a-Si:H to enhance built-in potential and form a homogeneous p/i-junction in the cell, which led to further improvement in the cell performance. The efficiencies of the cells with the PEDOT:PSS/IL window on glass and PI substrates were 7.40% and 6.52%, respectively, which were considerably higher than that of the cell with a conventional p-type microcrystalline (μc-) Si:H window. Also, the degradation of the cell with PEDOT:PSS window by bending was much smaller than the cell with p-type μc-Si:H window, particularly at bending radius < 10 mm. The present work demonstrates that PEDOT:PSS with a proper interfacial layer is a promising p-type window for substrate-type a-Si:H thin film solar cells and also for enhancing the flexibility of inorganic light absorbing materials-based solar cells on flexible film substrates.</P> <P><B>Highlights</B></P> <P> <UL> <LI> p-Type PEDOT:PSS windows were used for flexible a-Si:H thin film PV cells. </LI> <LI> PEDOT:PSS should be free from a damage caused by subsequent deposition process. </LI> <LI> Surfactant addition and H<SUB>2</SUB>-treatment improve the adhesion of PEDOT:PSS on a-Si:H. </LI> <LI> Insertion of highly B-doped Si leads to further improvement in cell performances. </LI> <LI> Cell with PEDOT:PSS showed higher flexibility than cell with p-type μc-Si:H particularly at bending radius < 10 mm. </LI> </UL> </P>

A high-performance flexible NO₂ sensor based on WO₃ NPs decorated on MWCNTs and RGO hybrids on PI/PET substrates

Yaqoob, U.,Uddin, A.S.M.I.,Chung, G.S. Elsevier Sequoia 2016 Sensors and actuators. B, Chemical Vol.224 No.-

This study explores the fabrication and evaluation of a flexible NO<SUB>2</SUB> sensor based on a tungsten trioxide nanoparticle-loaded, multi-walled carbon nanotube, reduced graphene oxide hybrid (WO<SUB>3</SUB> NP-loaded MWCNT-RGO) on a polyimide/polyethylene terephthalate (PI/PET) substrate. A viscous gel of the hybrid materials was prepared using α-terpineol. The fabricated sensor exhibits excellent NO<SUB>2</SUB> sensing with a maximum response of 17% to 5ppm, a limit of detection (LOD) of 1ppm, and relatively short response/recovery time (7/15min). The mechanical robustness of fabricated sensor was evaluated systematically at different curvature angles (0-90<SUP>o</SUP>) and after various times bending/relaxing (up to 10<SUP>7</SUP>). The sensor exhibits excellent mechanical flexibility and sensing properties at room temperature without significant performance degradation, even at a curvature angle of 90<SUP>o</SUP> and after 10<SUP>6</SUP> cycles of the bending/relaxing process. These results and the economical, light-weight and mechanically-robust features indicate that the proposed WO<SUB>3</SUB> NPs-MWCNTs-RGO hybrid sensor is a promising building block for the development of high-performance, flexible NO<SUB>2</SUB> sensors.

Use of 1.7 kV and 3.3 kV SiC Diodes in Si-IGBT/ SiC Hybrid Technology

Y. K. Sharma,L. Coulbeck,P. Mumby-Croft,Y. Wang,I. Deviny 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.73 No.9

Replacing conventional Si diodes with SiC diodes in Si insulated gate bipolar transistor (IGBT) modules is advantageous as it can reduce power losses significantly. Also, the fast switching nature of the SiC diode will allow Si IGBTs to operate at their full high-switching-speed potential, which at present conventional Si diodes cannot do. In this work, the electrical test results for Si-IGBT/4HSiC- Schottky hybrid substrates (hybrid SiC substrates) are presented. These substrates are built for two voltage ratings, 1.7 kV and 3.3 kV. Comparisons of the 1.7 kV and the 3.3 kV Si-IGBT/Si-diode substrates (Si substrates) at room temperature (20 C, RT) and high temperature (H125 C, HT) have shown that the switching losses in hybrid SiC substrates are miniscule as compared to those in Si substrates but necessary steps are required to mitigate the ringing observed in the current waveforms. Also, the effect of design variations on the electrical performance of 1.7 kV, 50 A diodes is reported here. These variations are made in the active and termination regions of the device.

Recent Advances of Flexible Hybrid Perovskite Solar Cells

신동희,허진혁,임상혁 한국물리학회 2017 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.71 No.10

Recently, hybrid perovskite solar cells have attracted great interest because they can be fabricated to low cost, flexible, and highly efficient solar cells. Here, we introduced recent advances of flexible hybrid perovskite solar cells. We introduced research background of flexible perovskite solar cells in introduction part. Then we composed the main body to i) structure and properties of hybrid perovskite solar cells, ii) why flexible hybrid perovskite solar cells are important?, iii) transparent conducting oxide (TCO) based flexible hybrid perovskite solar cells, and iv) TCO-free transparent conducting electrode (TCE) based flexible hybrid perovskite solar cells. Finally, we summarized research outlook of flexible hybrid perovskite solar cells.

Chip-on-board 형 세라믹-메탈 하이브리드 기판을 적용한 50와트급 LED 어레이 모듈의 제조 및 방열특성 평가

허유진,김효태 한국마이크로전자및패키징학회 2018 마이크로전자 및 패키징학회지 Vol.25 No.4

This paper describes the fabrication and heat transfer property of 50 watts rated LED array module where multiple chips are mounted on chip-on-board type ceramic-metal hybrid substrate with high heat dissipation property for high power street and anti-explosive lighting system. The high heat transfer ceramic-metal hybrid substrate was fabricated by conformal coating of thick film glass-ceramic and silver pastes to form insulation and conductor layers, using thick film screen printing method on top of the high thermal conductivity aluminum alloy heat-spreading panel, then co-fired at 515oC. A comparative LED array module with the same configuration using epoxy resin based FR-4 PCB with thermalvia type was also fabricated, then the thermal properties were measured with multichannel temperature sensors and thermal resistance measuring system. As a result, the thermal resistance of the ceramic-metal hybrid substrate in the 4 × 9 type LEDs array module exhibited about one third to the value as that of FR-4 substrate, implying that at least triple performance of heat transfer property as that of FR-4 substrate was realized. 가로등 및 방폭등용 고출력 LED 조명 시스템의 광원으로서, 다수의 LED 칩이 실장된 50와트급 LED 어레이모듈을 chip-on-board형 고방열 세라믹-메탈 하이브리드 기판을 사용하여 제작하였다. 고방열 세라믹-메탈 하이브리드 기판은 고열전도 알루미늄 금속 열확산 기판에 저온소결용 글라스-세라믹 절연 페이스트와 은 전극 페이스트를 후막 스크린 공정에 의해 도포한 다음, 건조 후 515oC 에서 동시소성하여 LED 칩을 실장할 세라믹 절연층과 은전극 회로층을 형성하여 제조하였다. 이 하이브리드 기판의 방열특성 평가를 위한 비교 샘플로서 기존의 에폭시 기반 FR-4 복합수지로 만든 써멀비아형 PCB 기판에도 동일한 디자인의 LED 어레이 모듈을 제작한 다음, 다중채널 온도측정장치와 열저항 측정기로 방열특성을 비교 분석하였다. 그 결과, 4 × 9 type LED 어레이 모듈에서 세라믹-메탈 하이브리드 기판의 열저항은써멀비아형 FR-4 기판에 비하여 약 1/3로 나타났으며, 이것은 곧 방열성능이 적어도 3배 이상 높은 것으로 볼 수 있다.

Hybrid 구조 신축성 기판 상 Active 소자 제작 기술 개발

박지훈(J. Park),박장웅(J.-U. Park) 한국정밀공학회 2016 한국정밀공학회 학술발표대회 논문집 Vol.2016 No.5월

Embedding 된 Hybrid 구조 기반 고유연성/고집적 유연기판 제작 기술 개발

박지훈(J. H. Park),박장웅(J. U. Park) 한국정밀공학회 2015 한국정밀공학회 학술발표대회 논문집 Vol.2015 No.12월