• Journal of the Korean Applied Science and Technology
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• v.13 no.3
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• pp.111-117
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• 1996

Many alternatives to Trichlorothane & Trichlorotrifluoroethane mainly used as cleaning solvent for industrial parts are developed and commercialized because the solvent is scheduled to phaseout after 1996. Considering there are many kinds of parts and contaminants in all parts cleaning, It is essential to investigating the characteristics and performance of the alternatives prior to use. For the contaminant of a standard oil, waters, hydrocarbon and halogen parts which are the comercially available and promising alternatives were experimented at the same condition of Trichlorothane & Trichlorotrifluoroethane to check the cleaning performance. Overally, the removal efficiency of halogen solvent parts was better than that of hydrocarbon or waters parts for removing the standard oil used in this experiment.

• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.24.1-24.1
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• 2010

In practical operation, the exposed surfaces may get dirty thus degrade the performance of devices. So the combination of self cleaning and antireflection is very desirable for use in outdoor photovoltaic and displaying devices, self cleaning windows and car windshields. For the purpose of self cleaning, the surface needs to be either superhydrophobic or superhydrophilic. However, in practice AR in the visible region and self cleaning are a pair of competitive properties. To satisfy the requirements for superhydrophobic or superhydrophilic surfaces, high surface roughness is required. But it usually cause severely light scattering. Photo-responsive coatings (TiO2, ZnO etc.) can lead to superhydrophilic. However, the refractive indices are high. Thus for porous structure, controlling pore size in the underwavelength scale to reduce the light scattering is very crucial for highly transparent and self cleaning antireflection coating. Herein, we demonstrate a simple method to make high performance broadband antireflection layer on the glass surface, by "carving" the surface by hot alkali solution. Etched glass has superhydrophilic surface. By chemical modification, it turns to superhydrophobic. Enhanced transparency (up to 97%) in a broad wavelength range was obtained by short time etching. Also antifogging effect has been demonstrated, which may offer advantage for devices working at high humidity environment or underwater. Compositional dependence of the properties was observed by comparing three different commercially available glasses.

• Clean Technology
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• v.19 no.3
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• pp.219-225
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• 2013

Environment-friendly and surfactant-free aqueous cleaning agents have been developed in order to solve various problems generated by surfactants in the aqueous cleaning agents. Aqueous surfactant-free cleaning agents, S-1 and S-2 have been formulated with water-soluble solvents such as propylene glycol and propylene glycol ether on their main components and with some additives. These solvents were chosen because of their good solubility in water and excellent solubility of fluxes which are major contaminants of printed circuit board in the electronic industry. Physical properties of the formulated and the imported cleaning agents were measured to predict their cleaning performance, and their cleaning abilities of flux and solder contaminants were evaluated under the various ultrasonic frequencies by a gravimetric method. The measurement results show that the physical properties of cleaning agent V are generally similar with those of formulated cleaning agents S-1 and S-2. Both the cleaning agent V and the formulated cleaning agents S-1 and S-2 showed similar trends that their pH decrease in the beginning and then increases later on with the increase of their dilution in water. It is considered that the wetting indices of the cleaning agents calculated with experimental values do not not have any influence on their cleaning ability. In ultrasonic cleaning tests under three ultrasonic frequencies of 28, 45, and 100 kHz, their best performances of cleaning solder and flux were obtained at 45 kHz and 28 kHz, respectively, and the cleaning performance of the formulated cleaning agents S-1 and S-2 was better than that of the cleaning agent V. However, in the case of the recommended diluted concentration of 25 wt% cleaning solution, the cleaning performance of the cleaner V for solder and flux was better in the initial stage of cleaning compared to the formulated cleaners. And it may be concluded that the formulated cleaning agents S-1 and S-2 can be applied to cleaning of solder and flux in the industry, based on the experimental results in this study.

• The Journal of the Acoustical Society of Korea
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• v.16 no.1E
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• pp.49-56
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• 1997

Ultrasonic cleaning at high frequency around 1 MHz, called megasonic cleaning, is commonly used to remove particles less than 1 ㎛ by generating high frequency accelerations on the cleaning objects. Cleaning is performed in an ultrasonically-excited liquid contained in a double-structured container. Ultrasonic waves generated by piezoelectric transducers propagate in the outer container and are transmitted through the inner container. The bottom of the inner container is inclined to make oblique incidence of the ultrasonic wave in order to raise the efficiency of the transmission through the bottom plate. This work deals with the efficiency of the transmission, which directly affects the cleaning performance. The transmission characteristics of the ultrasonic wave in the megasonic cleaner have been obtained analytically and numerically for the variations of some parameters, such as the thickness and inclined angle of the bottom plate of the inner container and the chemical ratio and temperature of the cleaning liquid. The calculated results have yielded the optimum cleaning condition in terms of the sound power transmitted into the cleaning liquid.

• Air Cleaning Technology
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• v.8 no.2 s.29
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• pp.48-70
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• 1995

• Journal of the Korea Fashion and Costume Design Association
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• v.21 no.1
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• pp.181-189
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• 2019

The washability, redeposition, fill power, and fabric damage of wet cleaning and dry cleaning solvents were measured to identify the optimal type of washing that would increase washability while maintaining dimensional stability. The soiled fabric is a polyester cotton blend and the types of soil were wine, blood, make-up and sebum with carbon black. Petroleum and silicone solvents were used in dry cleaning. Results from this study are as follows. First, detergency is significantly influenced by the type of washing and type of soil. Wet cleaning is superior to dry cleaning. Wet cleaning shows a strong washing performance against hydrophilic soils, whereas, dry cleaning is stronger against hydrophobic soils. Second, redeposition is significantly affected by the type of washing, fabrics, and soils. Redeposition occurred little on cotton during wet cleaning, but showed a high rate for nylon. However, when the two types of fabric were dry cleaned, redeposition occurred on both types. Third, the fill power of duck-down is very affected by the type of washing. Resilience is the best in wet cleaning; and in dry cleaning, petroleum solvents showed a higher resilience when as compared to silicone solvents. Last, the level of fabric damage to cotton fabrics is highly influenced by the type of washing. Wet cleaning damages cotton fabrics significantly more than dry cleaning. For dry cleaning, petroleum solvents damage these fabrics slightly more than silicone solvents. In conclusion, the type of soil must initially be identified to determine the optimal type of washing. Special caution is required when textiles with particulate soil and nylon are washed. When considering the resilience of duck-down clothing, wet cleaning is more appropriate than dry cleaning. Dry cleaning, especially when using silicone-based solvents, is more suitable than wet cleaning for maintaining the shape of clothing.

• Analytical Science and Technology
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• v.6 no.5
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• pp.521-530
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• 1993

According to the Montreal Protocol, CFC 113, one of the ozone-depleting substances, will be prohibited to use as a cleaning solvent essentially in the electronic industry. Therefore, the development of the alternative cleaning solvents to CFC 113 is being accelerated. A number of the alternative cleaning solvents are avialable on the market. The alternatives of Axarel 32(DuPont), Cleanthru 750H(KAO Chemical), and EC-Ultra(Petroferm) are chosen for the comparison of cleaning performance with CFC 113. The test methods for measuring the cleaning performance were composed of the measurement of the physical properties, the experiments on the material compatibility with cleaning solvents, the measurement of the evaporation rate, and finally the experiments of the removal efficiency. Normally the basic physical properties of the alternatives had higher boiling points, viscosity and surface tension, which were quite different to those of CFC 113. In terms of solubility of rosin-based flux, the solubilities of abietic acid (nonpolar organic) were similar, but those of the activator (polar organic) in the alternatives were better than CFC 113. The evaporation of the alternatives was very slow, compared to CFC 113, which had much lower boiling point. All the cleaning solvents showed the good material compatibility with FR4 and Cu-coated PCB. The better removal efficiencies of abietic acid were obtained when using the ultrasonic mechanical energy over the dipping method. The experiments also indicated the very slow-eavaporating solvent was not desirable with the dipping cleaning method, and the differences in the removal efficiency of the alternatives with the ultrasonic cleaning method were negligible. Among the alternatives, the overall cleaning performances were obsorved as almost similar. Before selecting the ultimate cleaning solvent, the application of cleaning machine, environmental issues, and economics are simultaneously considered with the cleaning performance.

• Journal of the Semiconductor & Display Technology
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• v.22 no.2
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• pp.17-23
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• 2023

In semiconductor manufacturing processes, a cleaning process is important that can remove sub-micron particles. Conventional wet cleaning methods using chemical have limits in removing nano-particles. Thus, physical forces of a mechanical vibration up to 1 MHz frequency, was tried to aid in detaching them from the substrates. In this article, we developed a 1 MHz quartz megasonic for a bare wafer cleaning using finite element analysis. At first, a 1 MHz megasonic prototype was manufactured. Using the results, a main product which can improve a particle removal performance, was analyzed and designed. The maximum impedance frequency was 992 kHz, which agreed well with the experimental value of 986 kHz (0.6% error). Acoustic pressure distributions were measured, and the result showed that maximum / average was 400.0~432.4%, and standard deviation / average was 46.4~47.3%. Finally, submicron particles were deposited and cleaned for the assessment of the system performance. As a result, the particle removal efficiency (PRE) was proved to be 92% with 11 W power. Reflecting these results, the developed product might be used in the semiconductor cleaning process.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.7 s.184
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• pp.7-13
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• 2006

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.1571-1578
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• 2015

The cleaning characteristics of pulse air jet type cleaning system which is widely applied in the industries were identified by utilizing the computational fluid dynamics (CFD) and the cleaning performance in modified shape of dedusting unit was compared in this study. The review on each shape of cleaning part showed that the case of installing the nozzle on the blow tube (Case-3) and the case of installing the double intaking tube to the venturi (Case-4 and Case-5) were more excellent than the structure (Case-1). Also, the optimal venturi shape was designed and examined its applicability to the site in a pilot scale plant. A combined system of a blow tube and a venturi proposed by this study turned out to be very effective for concentrating an cleaning air compared to existing systems, such as using only blow tube and combines the blow tube and venturi. In addition, as a result of installing and testing a venturi proposed by this study, the cleaning frequency and cleaning time were much improved compared to a case of using a commercial venturi that is under use at the industrial sites.