• Journal of the Semiconductor & Display Technology
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• v.22 no.4
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• pp.26-31
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• 2023

We investigated the impact of NF₃ / H₂O remote plasma dry cleaning conditions on the SiO₂ etching rate at different preparation states during the fabrication of ultra-large-scale integration (ULSI) devices. This included consideration of factors like Si crystal orientation prior to oxidation and three-dimensional structures. The dry cleaning process were carried out varying the parameters of pressure, NF₃ flow rate, and H₂O flow rate. We found that the pressure had an effective role in controlling anisotropic etching when a thin SiO₂ layer was situated between Si₃N₄ and Si layers in a multilayer trench structure. Based on these observations, we would like to provide further guidelines for implementing the dry cleaning process in the fabrication of semiconductor devices having 3D structures.

• Journal of the Semiconductor & Display Technology
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• v.23 no.2
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• pp.129-134
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• 2024

This study aims to talk about the necessity of solving the PFC gas emission problem raised by the recent development of the semiconductor industry and the remote plasma source method monitoring system used in the semiconductor industry. The 'monitoring system' means that the researchers applied machine learning to the existing monitoring technology and modeled it. In the process of this study, Residual Gas Analyzer monitoring technology and linear regression model were used. Through this model, the researchers identified emissions of at least 12700mg CO2 to 75800mg CO2 with values ranging from ion current 0.6A to 1.7A, and expect that the 'monitoring system' will contribute to the effective calculation of greenhouse gas emissions in the semiconductor industry in the future.

• Korean Journal of Materials Research
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• v.11 no.5
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• pp.361-366
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• 2001

It is difficult to obtain high Cu nucleation density and continuous Cu films in Cu-MOCVD without cleaning the TiN substrate prior to Cu deposition. In this study effects of plasma precleaning on the Cu nucleation density were investigated using SEM, XPS, AES, AFM analyses. Direct plasma pretreatment is much more effective than remote plasma pretreatment in enhancing Cu nucleation. Cleaning effects are enhanced with increasing the rf-power and the plasma exposure time in hydrogen plasma pretreatment. The mechanism through which Cu nucleation is enhanced by plasma pretreatment is as follows: Hydrogen ion\ulcorner in the hydrogen plasma react with TiN to form Ti and $NH_3$ Cu nucleation is easier on the Ti substrate than TiN substrate.

• Proceedings of the Korean Society of Laser Processing Conference
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• 2006.11a
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• pp.17-20
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• 2006

In the remote welding system using $CO_2$ laser, laser beam is rapidly deflected by moving mirrors of scanner system and has focusable distance over 1000mm from workpiece. From such arrangement, various advantages and disadvantages arise. Remote welding is a highly efficient laser process. As the mirrors of the scanner system allow positioning speeds exceeding 700m/s, it becomes possible to reduce the welding cycle time. On the other hand, as there no the provision of shielding gas which is normally required for beam powers exceeding 3kW, may become difficult task. Therefore, In this study, the influence of the various penetration of back bead by the different laser welding speed on the weld seam formation without shielding gas was investigated.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1954-1956
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• 2004

Nowadays, $CO_2$ lasers are used widely in many applications such as materials fabrication, communications, remote sensing and military purpose etc. Especially, $CO_2$ lasers are in the spotlight at surface handling and heat processing. It is important to control the laser output power and beam Quality in those fields. And those are studied the important parameters deciding the fluctuation of laser beam are smoothing capacitor, frequency and the characteristics of laser resonator. But the study of plasma parameters of $CO_2$ lasers are little. So we detect the $CO_2$ laser from emitted $CO_2$ laser discharge plasma using a non-contact photo tansistor sensor and Low pass filter. In this study, The relativity of the emitted light of discharge plasma and CO2 laser output.

• Journal of the Microelectronics and Packaging Society
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• v.16 no.3
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• pp.53-59
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• 2009

Low pressure mercury lamp type UV equipments have been widely used for cleaning and modification of PCB surfaces. To enhance the productivity of the process, we newly developed remote DBD type atmospheric pressure plasma equipment. The productivity of both equipments could be compared by measuring surface contact angle for various transferring speed. By the result of the measurement, we could verify that the productivity of the atmospheric pressure plasma be superior to the productivity of the UV equipment. XPS experiments confirmed that the surface effect of the UV and atmospheric pressure plasma processing are similar for each other. Organic contamination level was reduced after the processing and some surface elements were oxidized for both cases. Finally, the atmospheric pressure plasma equipment was adapted to flip chip BGA's flux printing process and it was concluded that the printing uniformity be enhanced by the atmospheric pressure plasma surface treatment.

• Journal of the Korean Vacuum Society
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• v.18 no.5
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• pp.337-345
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• 2009

When the drill hole diameter for the package substrate is under $100{\mu}m$, the smear in the drill hole cannot be eliminated by wet desmear process only. We intended to change the substrate's hydrophobic characteristics to hydrophilic characteristics by adapting the atmospheric pressure plasma prior to the wet desmear process. Atmospheric pressure plasma process was made as the inline type equipment which is adequate for the package substrate's manufacturing process and remote DBD type electrodes were used for the equipment. As the result of atmospheric pressure plasma processing, the contact angle of the substrate was enhanced from 71 degree to 30 degree. Dielectric film thickness, drill hole diameter and surface roughness were measured to evaluated the characteristics of the wet desmear process in case of plasma processing and in case of none. By the measurement, it was analyzed that the process uniformity within the whole panel was largely enhanced. Also, it was verified that the smear in the drill hole was eliminated efficiently which was analyzed by the SEM image of the drill hole.

• Journal of the Optical Society of Korea
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• v.17 no.6
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• pp.548-558
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• 2013

In this work, laser induced breakdown spectroscopy (LIBS) is used to investigate soil samples collected from different desert areas of Riyadh city in Saudi Arabia. Both qualitative analysis and plasma parameters are studied via the observed LIBS spectra. These experiments have been done using a Spectrolaser-7000 system with 50 mJ fundamental wavelength of Nd:YAG laser and detection delay time of 1 microsecond. Many spectral lines are highly resolved for many elements like Al, Fe, Mg, Si, Mn, Na, Ca and K. The electron temperatures Te and electron densities Ne, for the constituent of generated LIBS plasma, are determined for all the collected samples. It is found that both Te and Ne vary from one desert area to other. This variation is due to the change of the elemental concentration in different desert areas that affects the sample's matrices. Time dependent measurements have also been performed on the soil samples. While the signal-to-base ratio (SBR) reached its optimal value at 1 microsecond, the plasma parameters Ne and Te reach values of $4{\times}10^{17}cm^{-3}$ and 9235 K, respectively, at 2.5 microsecond. The later indicate that the plasma cooling processes are slow in comparison to the previously observed results for metallic samples. The observed results show also that in the future it is possible to enhance the exploitation of LIBS in the remote on-line environmental monitoring application, by following up only the values of Ne and Te for one element of the soil desert sample using an optical fiber probe.

• Korean Journal of Remote Sensing
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• v.15 no.4
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• pp.367-375
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• 1999

This paper describes the development, operations, and applications of ROCSAT-l and its Ocean Color Imager (OCI) remote-sensing payload. It is the first satellite program of NSPO. The satellite was successfully launched by Lockheed Martin's Athena on January 26, 1999 from Cape Canaveral, Florida. ROCSAT-l is a Low Earth Orbit (LEO) experimental satellite. Its circular orbit has an altitude of 600km and an inclination angle of 35 degrees. The satellite is designed to carry out scientific research missions, including ocean color imaging, experiments on ionospheric plasma and electrodynamics, and experiments using Ka-band (20∼30GHz) communication payloads. The OCI payload is utilized to observe the ocean color in 7 bands (including one redundant band) of Visible and Near-Infrared (434nm∼889nm) range with the resolution of 800m at nadir and the swath of 702km. It employs high performance telecentric optics, push-broom scanning method using Charge Coupled Devices (CCD) and large-scale integrated circuit chips. The water leaving radiance is estimated from the total inputs to the OCI, including the atmospheric scattering. The post-process estimates the water leaving radiance and generates different end products. The OCI has taken images since February 1999 after completing the early orbit checkout. Analyses have been performed to evaluate the performances of the instrument in orbit and to compare them with the pre-launch test results. This paper also briefly describes the ROCSAT-l mission operations. The spacecraft operating modes and ROCSAT Ground Segment operations are delineated, and the overall initial operations of ROCSAT-l are summarized.

• Proceedings of the Korean Vacuum Society Conference
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• 1996.06a
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• pp.36-37
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• 1996