• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
• /
• pp.583-588
• /
• 2005

Indium tin oxide (ITO) is a commonly used conducting transparent oxide film (CTO) used in flat panel display applications. Direct write laser ablation is sometimes employed for ITO patterning and it is important that the substrate material and remaining ITO be affected as little as possible by the laser ablation. In this investigation, femtosecond laser ablation of ITO was studied to identify laser processing parameters which cleanly ablated ITO with a minimum of damage to a glass substrate and surrounding ITO. The Ti:Sapphire chirp pulse amplified femtosecond laser used for the experiments had a wavelength of 775nm and produced pulses with a duration of 150fs at a rate of 2 kHz. Ablation was carried out at a sufficiently high panel scanning speed that single ablation spots could be studied. The pulse energy was adjusted to determine feasible spot diameters and depths which could be ablated into the ITO without damaging the glass substrate. Next, ablation of lines without glass damage was also demonstrated. Experiments were also performed with a high repetition rate (100kHz) femtosecond laser.

• Advances in Computational Design
• /
• 제8권3호
• /
• pp.219-236
• /
• 2023

In this paper, finite element modeling of the laser ultrasonics (LU) process in ablation regime is of interest. The momentum resulting from the removal of material from the specimen surface by the laser beam radiation in ablation regime is modeled as a pressure pulse. To model this pressure pulse, two equations are required: one for the spatial distribution and one for the temporal distribution of the pulse. Previous researchers have proposed various equations for the spatial and temporal distributions of the pressure pulse in different laser applications. All available equations are examined and the best combination of the temporal and spatial distributions of the pressure pulse that provides the most accurate results is identified. This combination of temporal and spatial distributions has never been used for modeling laser ultrasonics before. Then by using this new model, the effects of variations in pulse duration and laser spot radius on the shape, amplitude, and frequency spectrum of ultrasonic waves are studied. Furthermore, the LU in thermoelastic regime is simulated by this model and compared with LU in ablation regime. The interaction of ultrasonic waves with a defect is also investigated in the LU process in ablation regime. Good agreement of the results obtained from the new finite element model and available experimental data confirms the accuracy of the proposed model.

• 반도체디스플레이기술학회지
• /
• 제18권4호
• /
• pp.6-11
• /
• 2019

For a wider application of laser direct patterning, selective laser ablation of indium tin oxide (ITO) film on transparent oxide semiconductor (TOS) thin film was carried out using a diode-pumped Q-switched Nd:YVO₄ laser at a wavelength of 1064 nm. In case of the laser ablation of ITO on indium gallium zinc oxide (IGZO) film, both of ITO and IGZO films were fully etched for all the conditions of the laser beams even though IGZO monolayer was not ablated at the same laser beam condition. On the contrary, in case of the laser ablation of ITO on zinc oxide (ZnO) film, it was possible to etch ITO selectively with a slight damage on ZnO layer. The selective laser ablation is expected to be due to the different coefficient of thermal expansion (CTE) between ITO and ZnO.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1994년도 하계학술대회 논문집 C
• /
• pp.1425-1427
• /
• 1994

Laser ablation of glass substrates (8K-7 and synthetic quartz) using a transversely excited atmospheric (TEA) $CO_2$ laser has been inverstigated to obtain high speed etching. The ablation occurs by local heating of a substrate with a focused TEA-$CO_2$ laser beam. The dependence of ablation rate on pulse count and repetition-rate of laser has been discussed.

• 한국레이저가공학회:학술대회논문집
• /
• 한국레이저가공학회 2002년도 추계학술발표대회 논문개요집
• /
• pp.105-108
• /
• 2002

• Bulletin of the Korean Chemical Society
• /
• 제22권8호
• /
• pp.914-916
• /
• 2001

• 한국결정성장학회지
• /
• 제22권3호
• /
• pp.134-138
• /
• 2012

Recently the preparation magnetic nanoparticles by a pulsed laser ablation in liquid has gained much attention because it is easy to control experimental parameters. Iron oxide magnetic nanoparticles have been prepared by a pulsed laser ablation of ${\alpha}-Fe_2O_3$ target in ethanol at different magnitude of laser energy of 1, 20, 40 and 80 mJ/pulse. It revealed that particle size increases with increasing laser energy. It could be concluded that 40 mJ/pulse is an optimum laser energy for the preparation of iron oxide nanoparticles with uniform size distribution. The nanoparticles are homogeneously dispersed in ethanol and their stability maintained for several months.

• 소성∙가공
• /
• 제20권8호
• /
• pp.540-547
• /
• 2011

Recent years have seen advent of hot stamped parts made from laser-welded blanks of boron steels for structures requiring high crash energy absorption. However, the presence of Al-Si coating interfered with satisfactory mechanical characterizations after laser butt welding. In this study, laser ablation technology was considered in order to facilitate adequate mechanical characterization of the final hot-stamped panels.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2010년도 제39회 하계학술대회 초록집
• /
• pp.325-325
• /
• 2010

최근 결정질 실리콘 태양전지 분야에서는 태양전지의 Voc와 Isc의 증가를 통한 효율 향상을 목적으로 후면 passivation에 대한 연구가 활발하게 진행되고 있다. Local-Back Contact은 최적화된 후면 passivation 박막을 이용한 태양전지 제조방법이다. 고효율 태양전지 개발을 위해 최적의 laser 가공 조건이 확립되어야 한다. 본 연구에서는 고효율의 LBC 태양전지 개발을 위해 ONO 구조의 후면 passivation 박막에 laser ablation 조건을 가변하여 LBC 태양전지를 제작하고 그 특성을 분석하였다. 본 연구에 사용된 laser는 355nm 파장을 갖는 UV laser를 사용하였다. laser 파워는 5W, 주파수는 30kHz로 하였을 때 폭 20um, 깊이 5um의 홀을 형성시킬 수 있었다. 후면 접촉 면적의 영향을 확인하기 위하여 laser ablation 간격을 300um, 500um, 700um으로 가변하여 공정을 진행하였다. 태양전지 제조 결과 spacing 300um일 경우 효율이 높게 측정되었으며, laser ablation의 데미지를 줄이기 위한 FGA 처리시 웨이퍼 표면의 데미지를 줄여 carrier lifetime 향상에 기여하는 것을 확인할 수 있었다. 본 연구의 결과를 이용하여 향후 후면 passivation 극대화 및 접촉면적 가변을 통한 고효율 LBC 태양전지 개발이 가능할 것으로 판단된다.

• 한국전기전자재료학회논문지
• /
• 제15권6호
• /
• pp.551-557
• /
• 2002

Carbon nitride films have been deposited on Si(100) substrate by a high voltage discharge plasma combined with laser ablation in a nitrogen atmosphere. The films were grown both with the without the presence of an assisting focused Nd:YAG laser ablation. The laser ablation of the graphite target leads to vapor plume plasma expending into th ambient nitrogen arc discharge area. X-ray photoelectron spectroscopy and Auger electron spectroscopy were used to identify the binding structure and the content of the nitrogen species in the deposited films. The nitrogen content of the films was found to increase drastically with an increase of nitrogen pressure. The surface morphology of the films was studied using a scanning electron microscopy. Data of infrared spectroscopy and x-ray photoelectron spectroscopy indicate the existence of carbon-nitrogen bonds in the films. The x-ray diffraction measurements have also been taken to characterize the crystal properties of the obtained films.