Ultrasonic Spray Nozzle Research Articles

초음파 분사 노즐의 분사 범위에 따른 슬러리 막 두께의 변화가 재료제거율에 미치는 영향

Most of the consumables used in the CMP (Chemical Mechanical Planarization) process are discarded because it is difficult to reuse them. Slurry accounts for most of the consumables, so research is being conducted to reduce the amount of slurry used. A previous study explains that when the same amount of slurry is injected, the material removal rate is improved when the slurry is injected wide and thin instead of the tube nozzle, which is the conventional slurry injection method. However, there was no change in the injection method due to the problems of the injection method suggested in previous studies and the lack of follow-up studies. Thus, in this paper, an injection method through an ultrasonic spray nozzle is proposed to improve the problems of the injection method proposed in previous studies. Additionally, it is intended to calculate the slurry film thickness according to the spraying range and to explain the effect of the film thickness on the material removal rate.

Effect and Evaluation of an Ultrasonic Atomizer With Large Vibration Amplitude

An ultrasonic atomizer can produce large vibration amplitude is designed. Different from the structure of the usually seen ultrasonic spray nozzle, the atomizer is fundamentally constructed with a hollow tube encircled with several pieces of sectional type piezoelectric actuators, which can radially oscillate the tube to generate desired vibration profile. Atomization is formed on the surface around the liquid outlet of the tube where maximum vibration amplitude occurs. In search of resonance frequency and vibration amplitude, modal and harmonic analyses of the ultrasonic atomizer are carried out by ANSYS. In comparison the simulated results with the experimental results, both are in good agreement. A measurement system is set up for detecting the atomization droplets and calculating the droplet size and distribution. An attempt is to design an ultrasonic atomizer can produce high distribution and small diameter droplets for some application-level requirements, droplet diameter around 20–60 μm is assumed to be the specification for performance verification of the proposed atomizer. In experiment, it is found nearly 90% of atomized droplets fit for the requirement. Besides the most important factor of operating frequency, a relation of amplitude is found to include in the well-known Lang and Rayleigh’s equation.

ZnO twin-rods decorated with Pt nanoparticles for butanone detection

ZnO twin-rods were synthesized using a combination of the ultrasonic spray nozzle and microwave-assisted hydrothermal methods. The VOC detection test revealed that the decoration with 2% of Pt provides a more sensitive and selective butanone sensor.

Design of nanostructured WO3·0.33H2O via combination of ultrasonic spray nozzle and microwave-assisted hydrothermal methods for enhancing isopropanol gas sensing at room temperature

Hierarchical WO3·0.33H2O nanocolumns were prepared by a simple combination of ultrasonic spray nozzle (USN) and microwave-assisted hydrothermal (MAH) methods. The USN step promoted a high nucleation rate of H2WO4 clusters, while glycine played an important role in the crystal growth in a preferred direction. The MAH step was responsible for the crystallization of the single orthorhombic WO3·0.33H2O phase and the self-assembly of the hierarchical structure. The as-prepared sample was tested as a volatile organic compound (VOC) sensor at room temperature (22 °C) and wet conditions. Enhanced isopropanol sensitivity and selectivity were achieved due to the high specific surface area provided by the combination of USN and MAH methods. Thus, this synthesis strategy is a promising approach for fabricating different gas sensing devices.

Fabrication of composite particles by liquid–liquid interfacial crystallization using an ultrasonic spray nozzle

The purpose of this study was to produce composite particles, consisting of core starch particles coated with glycine, by liquid–liquid interfacial crystallization with an ultrasonic spray nozzle and to investigate the effect of operating conditions on glycine particle morphology. We confirmed that ultrasonic irradiation could improve the coating efficiency of the core starch particles during the crystallization process. We also investigated the transformation between different polymorphs of glycine crystals that covered the starch surface. The coating efficiency of the fine glycine crystals on the starch particles was improved by using an ultrasonic spray nozzle rather than anti-solvent crystallization without an ultrasonic spray nozzle. The glycine crystals on the surface of starch particles transformed from unstable to stable forms according to the solution-mediated mechanism and Ostwald rule of stages. The interaction between the core particles and guest particles was found to be a key factor in producing the composite particles. The results indicate that this crystallization process using the ultrasonic spray nozzle is promising for efficiently producing composite particles.

Thin films of carbon nanotubes via ultrasonic spraying of suspensions in N-methyl-2-pyrrolidone and N-cyclohexyl-2-pyrrolidone

Described is a method for ultrasonically spraying thin films of carbon nanotubes that have been suspended in organic solvents. Nanotubes were sonicated in N-methyl-2-pyrrolidone or N-cyclohexyl-2-pyrrolidone (CHP) and then sprayed onto a heated substrate using an ultrasonic spray nozzle. The solvent was quickly evaporated, leaving a thin film of randomly oriented nanotubes. Unlike other methods of spraying nanotube films, this does not require removal of surfactant after spraying and is compatible with creating films of functionalized nanotubes. Film thickness was controlled by the spray time and films were sprayed with thicknesses between 10 and 500 nm. Single-walled, multiwalled, and functionalized multiwalled nanotubes were sprayed. Transparent conducting thin films prepared by spraying single-walled carbon nanotubes dispersed in CHP demonstrated similar sheet resistance (for a given optical transmittance) as those prepared by spraying aqueous polymer-based dispersions that required postdeposition polymer removal.

Size Control of Particles with Changing Concentration of TIP used as a Precursor for Synthesis of TiO2 by Ultra-Sonic Spray and Pyrolysis Method

The nano sized titanium dioxide was synthesized by the ultra-sonic spray method and pyrolysis of TIP (titanium iso-propoxide), which was employed as the precursor solution. The fine liquid drop of the TIP sprayed by the ultra-sonic spray nozzle was conversed into TiO2 nano particles by pyrolysis through the hot tubular reactor. The concentration of TIP solution was controlled in the range of 0.1∼1.0 M and the morphology, the particle size, the crystal structure, and the surface area of synthesized TiO2 were investigated by SEM, TEM, XRD and N2-adsorption method, respectively. DSSC (dye sensitized solar cells) was also prepared by employing the synthesized TiO2 nano powder as the electrode and the photo-electrical property of TiO2 was compared in terms of efficiency of solar cells. It was further confirmed that the particle size of TiO2 was controlled with changing concentration of TIP solution. When 0.1 M TIP was used as the precursor solution, the size, the surface area and the crystal structure of synthesized TiO2 were approximately 10 nm (by TEM), 56 m2/g and the anatase structure, respectively. The particle size of TiO2 decreased with decreasing concentration of TIP solution. Therefore, it was concluded that the efficiency of DSSC's can be improved by employing high surface area and nano-sized TiO2 as the electrode.

Condensation of Acetol and Acetic Acid Vapor and Nitrogen Using Sprayed Aqueous Liquid

A cellulose-derived fraction of biomass pyrolysis vapor was simulated by evaporating acetol and acetic acid with heated nitrogen. After generating the vapor/nitrogen mixture, it was superheated in a tube oven and condensed by contact with an aqueous mist created by an ultrasonic spray nozzle. The rates of condensation and fractions of vapor condensed were determined for various fluid flow rates to estimate liquid flow rates necessary to obtain complete acetol vapor condensation. The effect of noncondensible gas on the condensation was determined by varying the ratio of nitrogen to acetol vapor. For standard conditions, no effect of nitrogen content on rate was seen for vapor contents greater than 10 mol %, which would include any practical fast pyrolysis vapor. Increasing the concentration of condensed vapor in the aqueous solution spray, up to 30 wt %, had little effect on the condensation rate.

An Experimental Study of Atomization Characteristics of the Ultrasonic Spray Nozzle

The recent development in advanced packaging and MEMS applications has created a need for high aspect ratio lithography processes, ultrasonic spray coating is a very appropriate method to meet this requirement, the parameters of atomization are greatly affected the spray quality. By using a laser-phase Doppler analyzer (PDA), an experimental study was conducted of the atomization characteristics of the ultrasonic spray nozzle, water was used as the liquid to be atomized instead of photoresist and air was used as the auxiliary gas instead of nitrogen, the parameters of atomization characteristics under different operating conditions were measured, such as mean diameter D10 and diameter distribution of atomized droplet particles etc. The experimental measurement results indicate that the flow rate of atomized liquid and auxiliary gas have a significant impact on the spray characteristics, the nozzle can achieve a comparatively good atomization state under the condition of a relatively small flow rate of atomized liquid or a relatively high flow rate of auxiliary gas, the mean diameter D10 of droplets can be 18.39μm. The research findings can provide an underlying basis for the application of the ultrasonic spray nozzle.

Spray coating of PMMA for pattern transfer via electron beam lithography on surfaces with high topography

Spray coating of polymethylmethacrylate (PMMA) as electron beam resist on non planar surfaces is presented as a reliable technique for deposition of uniform resist layers with adjustable thickness at wafer scale. In the experiments a commercial spray coating system with an ultrasonic spray nozzle was used. Parameters which influence the quality of the resist layer with respect to uniformity across a 4in Si wafer, such as ultrasonic power and dispensed volume, were evaluated. The suitability of spray coated PMMA for the pattern transfer on surfaces with high topography was proven by PMMA spray coating of 8μm deep trenches etched into Si wafers. The PMMA was then electron beam exposed and chromium line patterns were transferred on the Si surface via a lift-off process.

Formation of fine crystals of potassium chloride dissolved in aqueous ethanol solution by spray evaporation

Spray evaporation of aqueous ethanol solution with dilute potassium chloride (KCl) was examined for the generation of extremely small electrolyte crystals in dry state. Ethanol content in the aqueous solution played an important role in decreasing the solubility of KCl. Evaporation of small liquid droplets of the aqueous ethanol solution produced a small amount of KCl crystals. The concentration of ethanol in the solution was the operative variable, and the ultrasonic spray nozzle and flow rate of the solution were fixed in this study. The crystals collected were observed by SEM, and crystal size distributions were obtained for different operative conditions. The average crystal size ranged from 100 to 800 nm. When the ethanol content increased in the solution, the crystal size decreased. We consider the crystal size according to the slight solubility of KCl in liquid droplets of aqueous ethanol solution.

Dynamic Changes in LSM Nanoparticles on YSZ: A Model System for Non-Stationary SOFC Cathode Behavior

The interaction between nanoparticles of strontium-doped lanthanum manganite (LSM) and single-crystal yttria-stabilized zirconia (YSZ) was investigated using atomic force microscopy, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDX). Nanoparticles of LSM were deposited directly onto single-crystal YSZ (100) substrates using an ultrasonic spray nozzle. As samples were annealed from , nanoparticles gradually decreased in height and eventually disappeared completely. Subsequent reduction in at resulted in the reappearance of nanoparticles. Studies were carried out on identical regions of the sample, allowing the same nanoparticles to be characterized at different temperatures. Morphological changes indicate the formation of a thin layer of LSM, and XPS results support the observation by indicating an increase in signal from the La and Sr and a decrease in signal from the Y and Zr with increasing temperature. SEM/EDX was used to verify that the nanoparticles in the reduced sample contained La. The changes in the LSM/YSZ morphology may be important in explaining the nonstationary behavior observed in operating solid-oxide fuel cells (SOFCs). The thin layer of LSM initially results in poor cathode performance; reducing conditions then lead to film disruptions, indicating nano/microporosity, that increase oxygen ion diffusion and performance.

Photoresist Spray Coating for Resist Film Performance of Deep Silicon Cavities

In this paper, we describe a new method for resist performance with a photoresist spray coating system. The system consists of a high-temperature rotational chuck, an ultrasonic spray nozzle module, an angle control module, and a nozzle moving module. The spray coating system utilizes several parameters, including solid content, dispensed volume, the scanning speed of the spray nozzle, and the wafer dimensions. In order to prepare samples for photoresist spray coating, the process starts with a thermal oxidation at a thickness of 1000 ˚ Silicon oxide is used as a masking layer for anisotropic wet etching, 50 µm and 100 µm in depth. Photoresist spray coating consumes much less photoresist than conventional spin coating, and the resist uniformity of the deep cavities is more ecient.

Ultrasonic Spray Nozzle System with Piezoelectric Ceramics for Water Treatment Applications

A new type of ultrasonic spray nozzle was fabricated employing PZT and Pb-free piezoelectric device. The spray nozzle was designed to disperse chemicals in a water treatment mixing tank. The piezoelectrics were packaged in an aluminum case with silicone resin for the aqueous solution proof packaging. Chemicals were dispersed with high efficiency, and the ultrasonic fine particle spraying was able to reduce the chemicals consumption. The removal efficiencies of heterotrophic bacteria and Escherichia coli by chemicals injected using designed ultrasonic spray nozzle were higher than the conventional methods.

3차원 마이크로 구조를 위한 포토레지스트 스프레이 코팅

This paper presents the method for three-dimensional micro structure with photoresist spray coating system. The system consists of a high temperature rotational chuck, ultrasonic spray nozzle module, angle control module and nozzle moving module. Spray coating system is effected by several parameters such as the solid contents, the dispensed volume, the scanning speed of the spray nozzle and the wafer of dimension. The photoresist (AZ 1512) has been coated on the three-dimensional micro structure by spray coating system and the characteristics have been evaluated.