• Journal of ILASS-Korea
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• v.12 no.4
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• pp.185-190
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• 2007

There is a growing interest to develop a new cleaning technology to overcome the disadvantages of wet cleaning technologies such as environmental pollution and the cleaning difficulty of contaminants on integrated circuits. Laser cleaning is a potential technology to remove various pollutants on a wafer surface. However, there is no fundamental data about cleaning efficiencies and cleaning mechanisms of contaminants on a wafer surface using a laser cleaning technology. Therefore, the cleaning characteristics of a wafer surface using an excimer laser were investigated in this study. Fingerprint consisting of inorganic and organic materials was chosen as a representative of pollutants and the effectiveness of a laser irradiation on a wafer cleaning has been investigated qualitatively and quantitatively. The results have shown that cleaning degree is proportional to the laser irradiation time and repetition rate, and quantitative analysis conducted by an image processing method also have shown the same trend. Furthermore, the cleaning efficiency of a wafer contaminated by fingerprint strongly depended on a photothermal cleaning mechanism and the species were removed in order of hydrophilic and hydrophobic contaminants by laser irradiation.

• Journal of the Semiconductor & Display Technology
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• v.2 no.3
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• pp.1-6
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• 2003

In the rapid changes of the semiconductor manufacturing technologies for early 21st century, it may be safely said that a kernel of terms is the size increase of Si wafer and the size decrease of semiconductor devices. As the size of Si wafers increases and semiconductor device is miniaturized, the units of cleaning processes increase. A present cleaning technology is based upon RCA cleaning which consumes vast chemicals and ultra pure water (UPW) and is the high temperature process. Therefore, this technology gives rise to environmental issue. To resolve this matter, candidates of advanced cleaning processes have been studied. One of them is to apply the electrolyzed water. In this work, electrolyzed water cleaning was compared with various chemical cleaning, using Si wafer surfaces by changing cleaning temperature and cleaning time, and especially, concentrating upon the contact angle. It was observed that contact angle on surface treated with Electrolyzed water cleaning was $4.4^{\circ}$ without RCA cleaning. Amine series additive of high pKa (negative logarithm of the acidity constant) was used to observe the property changes of cathode water.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.162-163
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• 2016

Conventional window cleaning method has a number of limitations, for example, workers dependent and high crash risk. The purpose of this study is to derive the performance requirements of a window cleaning apparatus through technology survey. For this, we investigated the domestic and international patents related to window cleaning, and interviewed experts in the field of window cleaning and mechanical design. Through this research, we have proposed performance requirements of the window cleaning apparatus.

• Current Optics and Photonics
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• v.7 no.6
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• pp.714-720
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• 2023

Laser cleaning has the advantages of environmental protection, precision, and high efficiency, and has good prospects for application in removing oxide films on the surface of aluminum alloy. This paper discusses the cleaning threshold and cleaning mechanism of aluminum alloy surface oxide film. A nanosecond pulsed laser was used to remove a 5-㎛-thick oxide film from the surface of 7A04 aluminum alloy, and the target surface temperature and cleaning depth were simulated. The effects of different laser energy densities on the surface morphology of the aluminum alloy were analyzed, and the plasma motion process was recorded using a high-speed camera. The temperature measurement results of the experiment are close to the simulation results. The results show that the laser cleaning of aluminum alloy oxide film is mainly based on the vaporization mechanism and the shock wave generated by the explosion.

• The Journal of Korea Robotics Society
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• v.7 no.4
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• pp.243-251
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• 2012

In this paper, developing of a pool cleaning robot is addressed. First, we analyze commercial pool cleaning robot mechanisms, and the merits and demerits of wireless version of a pool cleaning robot is introduced. And then the water-jet moving mechanism for a pool cleaning robot is proposed to improve energy efficiency and mechanical design advantage, which is one of the strong candidates for wireless pool cleaning robots. Next, the method of cleaning performance evaluation of pool cleaning robots is firstly defined with five key factors, and it was verified by experimental results. If the cleaning performance can be quantitatively defined, we can design optimally a pool cleaning robot, which results in the cost down.

• Korean Membrane Journal
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• v.2 no.1
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• pp.60-63
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• 2000

The effect of Candida rugosa and steapsin lipase cleaning was investigated for ultrafiltration polyethersulphone membrane (30,000 dalton MWCO) fouled with the semi-synthetic type cutting oil. The experimental by the water circulator. The enzyme cleaning effect was measured with respect to temperature, cleaning time and enzyme concentration. The optimum cleaning condition for the system was 25$^{\circ}C$ and 2 hour cleaning with 1,000 unites/mL steapsin solution. The pure water flux improvement by the steapsin solution cleaning was about 17% at the optimum cleaning condition.

• Journal of the Korean Applied Science and Technology
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• v.14 no.2
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• pp.115-122
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• 1997

The field of printing use to pressurization ink using screen gassamer that is called screen printing. Existing cleaning solvent using screen printing are the organic solvents including aromatic compounds carried with poisonous and stench. Besides, cleaning method of current screen printing are for the most part mixed cleaning method of dipping and polish. Using 1,1,1-TCE, CFC-113 alternative system cleaning solvent be substituted for existing cleaning solvent against screen printing ink measured the cleaning efficiency according to gravimetric analysis method and property change of gassamer according to Image Analyzer. Also, Cleaning process system carry with excellent cleaning efficiency studied which was proposed new cleaning process including ultrasonic and vibration cleaning process be substituted for existing mixed cleaning method of dipping and polish.

• Journal of the Korean Applied Science and Technology
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• v.16 no.3
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• pp.237-240
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• 1999

This study showed that the optimized cleaning process using non-aqueous cleaning solvents is adaptable in the industrial field for existing 1.1.1-TCE cleaning solvents which is an ozone depleting sustance. Alternative cleaning solvent system substituted for existing cleaning solvent against non-aqueous pollutants(cutting & flux oil), was evaluated for the cleaning efficiency using gravimetric analysis method and surface change of sample by Image analyzer. The results showed that alternative solvents and process had excellent cleaning efficiency.

• Environmental Engineering Research
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• v.23 no.4
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• pp.474-484
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• 2018

The cleaning efficiency of reverse osmosis (RO) membranes inevitably fouled by organic foulants depends upon both chemical (type of cleaning agent, concentration of cleaning solution) and physical (cleaning time, flowrate, temperature) parameters. In attempting to determine the optimal procedures for chemical cleaning organic-fouled RO membranes, the design of experiments concept was employed to evaluate key factors and to predict the flux recovery rate (FRR) after chemical cleaning. From experimental results and based on the predicted FRR of cleaning obtained using the Central Composite Design of Minitab 17, a modified regression model equation was established to explain the chemical cleaning efficiency; the resultant regression coefficient ($R^2$) and adjusted $R^2$ were 83.95% and 76.82%, respectively. Then, using the optimized conditions of chemical cleaning derived from the response optimizer tool (cleaning with 0.68 wt% disodium ethylenediaminetetraacetic acid for 20 min at $20^{\circ}C$ with a flowrate of 409 mL/min), a flux recovery of 86.6% was expected. Overall, the results obtained by these experiments confirmed that the equation was adequate for predicting the chemical cleaning efficiency with regards to organic membrane fouling.

• Nuclear Engineering and Technology
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• v.52 no.3
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• pp.581-588
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• 2020

The membrane fouling is an important problem for FO applied to the radioactive wastewater treatment. The FO fouling characteristics for simulated radioactive wastewater treatment was investigated. On-line cleaning by deionized (DI) water and external cleaning by ultrasound and HCl were applied for the fouled membrane. The effectiveness and foulant removing amount by each-step cleaning were evaluated. The membrane fouling was divided into three stages. Co(II), Sr(II), Cs(I), Na(I) were all found deposited on both active and support layers of the membrane surface, resulting in membrane surface became rougher and more hydrophobic, which increased membrane resistance. On-line cleaning by DI water recovered the water flux to 69%. HCl removed more foulants than ultrasound.