• Journal of the Microelectronics and Packaging Society
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• v.23 no.4
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• pp.7-10
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• 2016

The post cleaning method for clean the shadow mask using in OLED (organic light emitting diode) emitter layer is always reforming. The cleaning solution and analysis method of shadow mask is still lack and not optimized. We use the simple and useful analytical method to determine the quantity and quality of organic and inorganic residue on surface of shadow mask. Finally analyze the cleaning solution using Raman spectroscopy efficiently.

• Journal of the Semiconductor & Display Technology
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• v.20 no.2
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• pp.34-42
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• 2021

Recent cleaning technologies of mask in extremely ultraviolet semiconductor processes were reviewed, focused on newly developed issues such as particle size determination or hydrocarbon and tin contaminations. In detail, critical particle size was defined and proposed for mask cleaning where nanosized particles and its various shapes would result in surface atomic ratio increase vigorously. A new cleaning model also was proposed with amphoteric behavior of electrolytically ionized water which had already shown excellent particle removing efficiency. Having its non-equilibrium and amphoteric properties, electrolyzed ion water seemed to oxidize contaminant surface selectively in nano-scale and then to lift up oxidized ones from mask surface very effectively. This assumption should be further investigated in future in junction with hydrogen bonding and cluster of water molecules.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.2
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• pp.111-117
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• 2008

We have studied surface roughness, contamination of impurity, bonding with some gas element, reflectance and zeta potential on masks to be generated or changed during photolithography/dry or wet etching process. Mask surface roughness was not changed after photolithography/dry etching process. But surface roughness was changed on some area under MoSi film of Cr/MoSi/Qz. There was not detected any impurity on mask surface after plasma dry etching process. Reflectance of mask was increased after variable plasma etching treatment, especially when mask was treated with plasma including $O_2$ gas. Blank mask was positively charged when the mask was treated with Cr plasma etching gas($Cl_2:250$ sccm/He:20 $sccm/O_2:29$ seem, source power:100 W/bias power:20 W, 300 sec). But this positive charge was changed to negative charge when the mask was treated with $CF_4$ gas for MoSi plasma etching, resulting better wet cleaning. There was appeared with negative charge on MoSi/Qz mask treated with Cr plasma etching process condition, and this mask was measured with more negative after SC-1 wet cleaning process, resulting better wet cleaning. This mask was charged with positive after treatment with $O_2$ plasma again, resulting bad wet cleaning condition.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.183-183
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• 2012

In the era of 45 nm or beyond technology, conventional etch mask using photoresist showed its limitation of etch mask pattern collapse as well as pattern erosion, thus hard mask in etching became necessary for precise control of etch pattern geometry. Currently available hard mask materials are amorphous carbon and polymetric materials spin-on containing carbon or silicon. Amorphous carbon layer (ACL) deposited by PECVD for etch hard mask has appeared in manufacturing, but spin-on carbon (SOC) was also suggested to alleviate concerns of particle, throughput, and cost of ownership (COO) [1]. SOC provides some benefits of reduced process steps, but it also faced with wiggling on a sidewall profile. Diamond like carbon (DLC) was also evaluated for substituting ACL, but etching selectivity of ACL was better than DLC although DLC has superior optical property [2]. Developing a novel material for pattern hard mask is very important in material research, but it is also worthwhile eliminating a potential issue to continuously develop currently existing technology. In this paper, we investigated in-situ dry-cleaning (ISD) monitoring of ACL coated process chamber. End time detection of chamber cleaning not only provides a confidence that the process chamber is being cleaned, but also contributes to minimize wait time waste (WOW). Employing Challenger 300ST, a 300mm ACL PECVD manufactured by TES, a series of experimental chamber cleaning runs was performed after several deposition processes in the deposited film thickness of $2000{\AA}$ and $5000{\AA}$. Ar Actinometry and principle component analysis (PCA) were applied to derive integrated and intuitive trace signal, and the result showed that previously operated cleaning run time can be reduced by more than 20% by employing real-time monitoring in ISD process.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.5
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• pp.353-357
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• 2010

Recently, silicon etching have received much attention for display industry, nano imprint technology, silicon photonics, and MEMS application. After the etching process, removing of etch mask and residue of sidewall is very important. The investigation of the etched mask removing was carried out by using the ashing, HF dipping and acid cleaning process. Experiment shows that oxygen component of reactive gas and photoresist react with silicon and converting them into the mask fence. It is very difficult to remove by using ashing or acid cleaning process because mask fence consisted of Si and O compounds. However, dilute HF dipping is very effective process for SiOx layer removing. Finally, we found optimized condition for etched mask removing.

• Journal of Korean Society on Water Environment
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• v.21 no.1
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• pp.29-33
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• 2005

In order to recycle the waste material and to develop the thickening unit of waste activated sludge from wastewater treatment facilities, the filtration bio-reactor equipped with a shadow mask filter module was employed for this work from which the operating properties and parameters were drawn. The sludge thickening and filtration unit is made of cylindrical acryl tank(12cm i.d. ${\times}$ 58cm height: working volume of 6L), where the flat-sheet type of shadow mask filter module(pore size: 220~250um, opening area: 34.8~39.6%) was installed and the effluent was withdrawn from the effluent port at the lowest point of the reactor, and the filtration was performed only by the hydraulic pressure. For evaluating the operating performance of this reactor, some parameters such as the solid-liquid separation of different biomass concentrations, the water quality of filtrate, the aeration cleaning time and the cleaning effect were investigated. Depending on the MLSS concentrations, the different time to withdraw 3L of filtrate was required in which the longer filtration time was necessary for the higher MLSS concentrations caused by the thicker formation of cake layer: 40 minutes for 5,000 mg/L, 70 minutes for 10,000 mg/L and 100 minutes for 15,000 mg/L, where the concentrations of SS were 8.9, 6.7 and 6.5 mg/L, respectively. Under the same operating conditions (the intensity of aeration cleaning: 80 L/min, MLSS: 10,000 mg/L), the proper aeration cleaning time was revealed 30 seconds, and the stable formation of cake layer was in the range of 10 to 15 minutes. Therefore, the shadow mask considered as a waste material can be of use as a filter material for the sludge thickening system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.88-89
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• 2009

In this paper, we investigated about wet cleaning effect as deep trench formation methods for Power chip devices. Deep trench structure was classified by two methods, PSU (Poly Stick Up) and Non-PSU structure. In this paper, we could remove residue defect during wet. cleaning after deep trench etch process for non-PSU structure device as to change wet cleaning process condition. V-SEM result showed void image at the trench bottom site due to residue defect and residue component was oxide by EDS analysis. In order to find the reason of happening residue defect, we experimented about various process conditions. So, defect source was that oxide film was re-deposited at trench bottom by changed to hydrophobic property at substrate during hard mask removal process. Therefore, in order to removal residue defect, we added in-situ SCI during hard mask removal process, and defect was removed perfectly. And WLR (Wafer Level Reliability) test result was no difference between normal and optimized process condition.

• The Journal of the Convergence on Culture Technology
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• v.8 no.1
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• pp.591-596
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• 2022

Various COVID-19 quarantine guidelines and measures are being taken by country at the WHO, but the number of confirmed cases has not decreased significantly. In order to prevent the inflow and outflow of COVID-19 through individual droplets, it is mandatory to wear a mask anytime, anywhere. However, as virus bacteria entering the mask amplify, it pollutes the mask and causes a disgusting smell. In this paper, a new method of preventing the spread of COVID-19 was proposed by sterilizing the mask with a dental gait spray introduced into the mask that has been used for a long time. Dental gargle water is usually produced by electrolysis of tap water, and the unstable ion water (HOCl) dissolved in water penetrates the cell barrier of various viruses and fails to act in its nucleus, causing water to self-purify. As a result of the experiment, when the mask used for a long time was washed with gargle water spray, the washed mask was dried after 10 minutes, and the smell of virus droplets or saliva almost disappeared. In particular, as a result of MOS testing the fit of the subjects who participated in the mask cleaning, it was excellent at 4.4 on average. Therefore, the mask was disposable, but if the spray was washed in the proposed method more than twice a day, the mask could be used in a comfortable state for more than a week.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.1
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• pp.199-206
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• 2005

Mask manufacturing is a high COC and COO process in developing of semiconductor devices because of mask production tool with high resolution. Direct writing has been thought to be the one of the patterning method to cope with development or small-lot production of the device. This study consists two categories. One is the additional process of the direct and maskless patterning generation using SLA for easy and convenient application and the other is a removal process using wet-etching process. In this study, cured status of epoxy pattern is most important parameter because of the beer-lambert law according to the diffusion of UV light. In order to improve the contact force between patterns and substrate, prime process was performed and to remove the semi-cured resin which makes a bad effects to the pattern, spin cleaning process using TPM was also performed. At a removal process, contact force between photo-curable resin as an etching mask and Si wafer is important parameter.

• Particle and aerosol research
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• v.6 no.2
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• pp.81-90
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• 2010

Several studies have suggested the possibility of airborne transmission of infectious diseases such as tuberculosis, pandemic influenza. because the number of patients increases explosively, if infectious disease had a high basic reproduction number, pharmaceutical interventions such as vaccination, chemoprophylaxis in the early stage of epidemic. Thus, non-pharmaceutical interventions such as mask-wearing, installing air cleaners, school closure are important to control and prevent the infectious diseases. However, the current technology on the mask, air cleaning, ventilation, and etc., seems to be not originated from the understanding of infection via airborne transmission. It is important to estimate the aerodynamic behavior of saliva droplets by coughing or speaking in order to understand the phenomena of airborne infection. In addition, the prediction of transmission of infectious diseases through the air is critical to prevent or minimize the damage of infection. In this review, we reviewed the recent studies on the airborne infection by focusing on the aerodynamic characteristics of saliva droplets and modeling of airborne transmission.