Type Of Chelating Agent Research Articles

Removal rate and surface quality of the GLSI silicon substrate during the CMP process

Silicon wafers have been widely used as substrate in the Giga large-scale integration (GLSI). Silicon chemical mechanical polishing (CMP) factors are very important for the polished silicon surface state, because they play an important role in the quality and yield of devices. The effect of CMP factors on silicon substrate removal rate and surface quality used for advanced technology nodes integrated circuit (IC) manufacturing was the focus of this study. In particular, the effect of pH, temperature, and abrasive concentration on silicon CMP were investigated. The alkaline slurry used in the experiments was a non-hydrogen peroxide based system containing a novel type chelating agent and a surfactant. The pH experiments showed that the silicon removal rate depends on the slurry pH, surface roughness and haze are decreasing with the increase of the slurry pH. The temperature and abrasive concentration experiments proved that the polishing temperature and the abrasive concentration have some effect on silicon removal rate, surface roughness, and haze. The silicon removal rate increases with the increase of the abrasive concentration, while the surface roughness and haze decrease; moreover, with the increase of the polishing temperature, the silicon removal rate, surface roughness, and haze increase. Silicon CMP is a combination of mechanical and chemical processes, which shows that the increase in both the mechanical and chemical effects can contribute to the increase in the silicon removal rate. Furthermore, the surface quality (roughness and haze) depends on the mechanical and chemical effects; the increase in the chemical effect is favorable but that in the mechanical effect is harmful to the surface quality. The results obtained facilitate the study of silicon CMP and other materials.

Investigation of stabilization mechanism and size controlling of Fe3O4 nanoparticles using anionic chelating agents

Chelating agents have potential effects on different properties of nanoparticles. Fe3O4 nanoparticles were synthesizes Using coprecipitation technique and oxalic, citric, stearic and lauric acids with concentrations of 0.5, 1, 2, and 5vol% were utilized as the chelating agents. Subsequently, stability, structural, and magnetic properties of the samples were studied using measurement of zeta potential as well as FT-IR, XRD, DLS, TEM, and VSM analyses. It was found that the lower end of the size range was achieved for all samples utilizing 2vol% chelating agents. So, in the present study, it was chosen as the optimum volume percentage of the chelating agents. Furthermore, for the nanoparticles treated with oxalic and citric acids, particle sizes were lower and the zeta potentials were larger comparing to those treated with stearic and lauric acids, which is an indication of their higher stabilization ability. Finally, the type of chelating agents had negligible effects on the structural and magnetic properties of the synthesized nanoparticles.

A new kind of chelating agent with low pH value applied in the TSV CMP slurry**Project supported by the Major National Science and Technology Special Projects (No. 2009ZX02308), the Fund Project of Hebei Provincial Department of Education, China (No. QN2014208), the Natural Science Foundation of Hebei Province, China (No. E2013202247), and the Colleges and Universities Scientific Research Project of Hebei

TSV (through silicon via) is an emerging technology, which can realize micromation compared with the conventional packaging and extend Moore's law. Chemical mechanical polishing (CMP) is one of the most important steps in the process of TSV manufacture, and it is an enabling technology to extend Moore's law in the past two decades. Low pressure, low abrasive and low pH value are the main requirements for copper interconnection. In this paper, the effect of different kinds of TSV slurry with FA/O II or FA/O IV type chelating agent on CMP are studied. All kinds of slurry used in this study are alkaline with no added inhibitors. From the experiment results, it can be seen that the copper removal rate and surface roughness achieved by using the FA/O IV type chelating agent with a low pH value is superior to using the FA/O II type chelating agent.

Efficacy of etidronic acid, BioPure MTAD and SmearClear in removing calcium ions from the root canal: An in vitro study.

Objective:The purpose of this study was to quantify the amount of calcium ions removed from the root canal by etidronic acid (HEBP), BioPure MTAD, and SmearClear using atomic absorption spectrophotometer.Materials and Methods:Fifty (n = 50) freshly extracted human mandibular premolar teeth were collected and decoronated at the cementoenamel junction. The canals were prepared in a crown down fashion using the rotary system and copiously irrigated with 1.0% sodium hypochlorite. All specimens were rinsed with the deionized water. Based on the type of chelating agent used, the samples (n = 10) were randomly divided into five (four test and one negative control) groups. Accordingly, Group I - 9% HEBP, Group II - 18% HEBP, Group III - SmearClear, Group IV - BioPure MTAD, and Group V - normal Saline. Subsequent to irrigation, the solution was collected in a test tube and subjected to atomic absorption spectrophotometer for the quantification of calcium ions removed from the root canal.Results:The mean concentration of calcium ions removed from the root canal (mean ± standard deviation) in all groups (I–V) were 13.32 ± 0.54 μg/ml, 16.36 ± 0.27 μg/ml, 20.04 ± 0.24 μg/ml, 18.15 ± 0.39 μg/ml, and 8.74 ± 0.49 μg/ml, respectively.Conclusions:SmearClear was the most effective agent for the removal of calcium ions from the root canal. Hence, its combined use with an organic solvent can be recommended for efficient smear layer removal.

Antibody mediated rejection of renal transplantation – Clinicopathological correlation

Immobilized metal affinity membranes (IMAMs) were prepared by immobilizing copper ions on microporous regenerated cellulose membranes through different types of chelating agents (dentate and triazine dye). The resulting chelator utilization percentages were 95% for iminodiacetic acid, 56% for N,N,N-tris(carboxymethyl)ethylenediamine, 52% for Cibacron blue 3GA, and 140% for Cibacron red 3BA. On the other hand, triazine dyes were slightly superior to dentate chelators on metal ion utilization for protein adsorption. In batch single-protein adsorptions, the protein adsorption capacity decreased with increasing molecular size and number of accessible surface histidine residues [lysozyme>bovine serum albumin (BSA)>γ-globulin], while the binding strength order was the opposite (γ-globulin>BSA>lysozyme). Moreover, the proportions of specific and nonspecific bindings were evaluated by varying pH and salt concentration conditions. A large fraction of the adsorption capacity was found to come from the nonspecific interactions for the prepared IMAMs. Lastly, batch three-protein adsorptions were performed and weak adsorption competition was observed.

Effect of novel alkaline copper slurry on 300 mm copper global planarization

The copper removal rate and uniformity of two types copper slurries were investigated, which was performed on the 300 mm chemical mechanical planarization (CMP) platform. The experiment results illustrate that the removal rate of the two slurries is nearly the same. Slurry A is mainly composed of a FA/OII type chelating agent and the uniformity reaches to 88.32%. While the uniformity of slurry B is 96.68%, which is mainly composed of a FA/OV type chelating agent. This phenomenon demonstrates that under the same process conditions, the uniformity of different slurries is vastly different. The CMP performance was evaluated in terms of the dishing and erosion values. In this paper, the relationship between the uniformity and the planarization was deeply analyzed, which is mainly based on the endpoint detection mechanism. The experiment results reveal that the slurry with good uniformity has low dishing and erosion. The slurry with bad uniformity, by contract, increases Cu dishing significantly and causes copper loss in the recessed region. Therefore, the following conclusions are drawn: slurry B can improve the wafer leveling efficiently and minimize the resistance and current density along the line, which is helpful to improve the device yield and product reliability. This investigation provides a guide to improve the uniformity and achieve the global and local planarization. It is very significant to meet the requirements for 22 nm technology nodes and control the dishing and erosion efficiently.

Removal of residual CuO particles on the post CMP wafer surface of multi-layered copper

This article introduces the removal technology of CuO particles on the post CMP wafer surface of multi-layered copper. According to the Cu film corrosion curve with different concentrations of H2O2 and the effect curve of time on the growth rate of CuO film, CuO film with the thickness of 220 nm grown on Cu a surface was successfully prepared without the interference of CuCl2-2H2O. Using the static corrosion experiment the type of chelating agent (FA/O II type chelating agent) and the concentration range (10–100 ppm) for CuO removal was determined, and the Cu removal rate was close to zero. The effect of surfactant on the cleaning solution properties was studied, and results indicated that the surfactant has the effect of reducing the surface tension and viscosity of the cleaning solution, and making the cleaning agent more stable. The influence of different concentrations of FA/O I type surfactant and the mixing of FA/O II type chelating agent and FA/O I type surfactant on the CuO removal effect and the film surface state was analyzed. The experimental results indicated that when the concentration of FA/O I type surfactant was 50 ppm, CuO particles were quickly removed, and the surface state was obviously improved. The best removal effect of CuO on the copper wiring film surface was achieved with the cleaning agent ratio of FA/O II type chelating agent 75 ppm and FA/O I type surfactant 50 ppm. Finally, the organic residue on the copper pattern film after cleaning with that cleaning agent was detected, and the results showed that the cleaning used agent did not generate organic residues on the film surface, and effectively removes the organic residue on the wafer.

Tuning the dissolution kinetics of wollastonite via chelating agents for CO2 sequestration with integrated synthesis of precipitated calcium carbonates

Carbon mineralization has recently received much attention as one of the most promising options for CO2 sequestration. The engineered weathering of silicate minerals as a means of permanent carbon storage has unique advantages such as the abundance of naturally occurring calcium and magnesium-bearing minerals and the formation of environmentally-benign and geologically stable solids via a thermodynamically favored carbonation reaction. However, several challenges need to be overcome to successfully deploy carbon mineralization on a large scale. In particular, the acceleration of the rate-limiting mineral dissolution step along with process optimization is essential to ensure the economic feasibility of the proposed carbon storage technology. In this study, the effect of various types of chelating agents on the dissolution rate of calcium-bearing silicate mineral, wollastonite, was explored to accelerate its weathering rate. It was found that chelating agents such as acetic acid and gluconic acid significantly improved the dissolution kinetics of wollastonite even at a much diluted concentration of 0.006 M by complexing with calcium in the mineral matrix. Calcium extracted from wollastonite was then reacted with a carbonate solution to form precipitated calcium carbonate (PCC), while tuning the particle size and the morphological structure of PCC to mimic commercially available PCC-based filler materials.

Optimization of Morphology and Particle Size of Modified Sol Gel Synthesized YSZ Nanopowder Using Taguchi Method

The morphology and particle size of yttria stabilized zirconia (YSZ) nanopowders synthesized by Pechini's method are very much dependent on the type of chelating agent, pH of solution, calcinations temperature, calcinations time, etc. In the present study, the influence of process parameters like the type of zirconium salt, pH of solution, calcinations temperature and time on the morphology and particle size of a YSZ nanopowder was analyzed by the Taguchi Design method and analysis of variance (ANOVA). According to the experimental results and ANOVA, the pH of solution and calcinations temperature are the most significant factors influencing the morphology and particle size of YSZ nanopowder; pH of solution is the most significant factor influencing the morphology; and calcinations temperature is the most significant factor affecting the particle size. Models were developed for predicting the morphology and particle size of the YSZ nanopowder. They were found to be in good agreement with the experimental results. The models were tested for experimental conditions and were found to be close to predicted values. Both morphology and particle size of YSZ nanopowders were mainly dependent on the pH of solution.

High catalytic activity of cobalt (II)-triethylamine complex towards orange II degradation with H2O2 as an oxidant under ambient conditions

Abstract The cobalt (II)–triethylamine (TEA) complex was found for the first time to degrade orange II with remarkable high activity using H2O2 as an oxidant under mild conditions. The effects of several parameters such as the types of chelating agents, the concentrations of Co2 +, TEA and H2O2, and the temperature on the degradation efficiency of the complex were investigated. It was suggested by the electron spin resonance spin-trapping technologies that the produced hydroxyl radicals were to be responsible for the dye decolorization. This study can provide us a simple, effective and economic system ideal for the treatment of toxic and nonbiodegradable azo dye.

Coenzyme Q10 Levels in β-Thalassemia and its Association with Ferritin Levels and Chelation Therapy

The aim of this study was to evaluate the plasma coenzyme Q10 (CoQ10) concentration, a vitamin-like substance found in every cell, which is also viewed as the most effective membrane antioxidant, of thalassemic patients and investigate the effect of chelating agents and ferritin levels on its concentration in patients with β-thalassemia major (β-TM). The study included 44 β-TM patients undergoing deferasirox (DFRA) or deferoxamine (DFO) chelation monotherapies or combined therapy with deferiprone (L1) and DFO, 20 patients with β-thalassemia (β-thal) traits and a control group of 22 healthy sex- and age-matched subjects. Complete blood counts, liver and renal function tests, lipid profiles, ferritin and plasma CoQ10 [by high performance liquid chromatography (HPLC)] were analyzed. The mean age (14.7 ± 7.3 years; median 14.3 years) and sex (26 males, 18 females) of the β-TM patients were not statistically different from the β-thal trait patients and the control group. The plasma CoQ10 concentration was 0.425 ± 0.136 μmol/L in β-TM patients, 0.508 ± 0.159 μmol/L in the β-thal trait patients and 0.534 ± 0.133 μmol/L in the control group. The difference was significant in both the β-TM (p < 0.001) and β-thal trait patients (p <0.05) compared to the control group. The CoQ10 concentration was also associated with ferritin levels in β-TM patients; the β-TM patients with high ferritin levels had a lower CoQ10 (p <0.05) concentration. Also, higher plasma CoQ10 levels were detected in β-TM patients undergoing DFRA treatment, according to combined therapy administered (0.457 ± 0.115 vs. 0.382 ± 0.127 mg/dL respectively, p <0.05). In conclusion, both the β-thal trait and β-TM patients have lower antioxidant capacity as demonstrated by the lower CoQ10 levels. The type of chelating agents and ferritin levels are factors effecting CoQ10 concentration in β-TM patients.

The Effect of Various Chelating Agents on the Thermal Decomposition of Cerate-Zirconate Ceramics Powder

In this work, BaCe0.54Zr0.36Y0.1O2.95 (BCZY) ceramics powder was synthesized using four types of chelating agents by a modified sol-gel method. The aim of this work is to study thermal decomposition of the sample that prepared using metal nitrate salt (M+), respective to chelating agents (C) and ethylene glycol (EG) at molar ratio of M+:C:EG = 3:3:2. The gel obtained was heated in a furnace at 325°C and 1100°C, respectively to produce light-yellow powder. The thermal behavior of the dried powder (T=325°C) was analyzed by thermogravimetric analysis (TGA) and Fourier infrared spectroscopy (FTIR). TGA results indicate that all the samples were almost completly decomposed at ∼ 900°C except for NTA that showed the lowest thermal decomposition at 580°C. FTIR spectra illustrated that the carbonate residue still remained in the powders even after calcined at 1100°C. It was found that the different chelating agents used lead to the different thermal characteristics of the BCZY powder.

Efficiency of chelating agents in retaining sludge-borne heavy metals in intensively applied agricultural soils

This paper presents an evaluation of different chelating agents for their effectiveness in removing Cu, Co and Zn in three distinctly different types of sludge-amen- ded soils. Soil types (Luvisol, Arenosol and Vertisol) were each mixed with an anaerobically digested sludge at a 1:1 ratio followed by leaching with three types of chelating agents, namely: ethylenediamine tetra acetic acid, nitrilo- triacetic acid and acetic acid. Aqua regia method was used to quantify pseudo total metal before and after treatment. Generally, chelating agents can be out competed by soil colloids in attracting cations. The efficiency of chelating agents was found to follow this order ethylenediamine tetra acetic acid nitrilotriacetic = acetic acid in all the three metals, with ethylenediamine tetra acetic acid being the most effective chelating agent. More heavy metals were removed in Luvisol and Arenosol than in Vertisol implying that soils rich in clay fraction retain more cations than soils with minimal clay fraction. Similarly, copper responded positively to chelation than zinc and cobalt in Luvisols and Arenosols, although the results were not conclusive for Vertisols.

폴리다이아세틸렌 베시클을 이용한 킬레이트제의 색전이 검출

본 연구에서는 폴리다이아세틸렌(polydiacetylene, PDA) 베시클을 이용하여 여러 가지 킬레이트제(chelating agent)를 쉽게 검출할 수 있는 센서 시스템을 개발하였다. 다른 센서들과 비교하여 PDA기반 센서는 많은 장점이 있다. 첫째로, 형광물질의 부착이 필요 없는 무표지 검출(label-free detection)이 가능하여 실험 절차가 간단하고 빠르다. 둘째로, PDA는 청색에서 외부 자극에 의해 적색으로 변화하는 색전이를 일으키므로 육안으로 쉽게 검출을 확인할 수 있었다. 끝으로, 특정 파장에서의 colorimetric response를 측정하여 각각의 킬레이트제의 농도에 따른 정량검출도 가능하다. 본 연구에서는 5가지 종류의 킬레이트제, 즉 EDTA, EGTA, NTA, DCTA, DTPA를 PDA 베시클과 반응시켰으며, 이중에서 EDTA, DCTA는 특히 강한 반응으로 PDA의 색전이를 유도함을 알 수 있었다. 본 연구를 통하여 PDA 베시클을 사용하여 어떠한 기계나 동력을 사용하지 않고 색전이를 이용하여 킬레이트를 성공적으로 검출할 수 있음을 보여주었다. In this research, we developed a sensor system which can easily detect several chelating agents using polydiacetylene(PDA) vesicles. In comparison to other sensors, PDA based sensor has several advantages. First, detection method is much simpler and faster because it does not require any labeling step in the experiment procedure. Second, significant color-transition from blue to red based upon external stimulus allows us the detection by naked eyes. Finally, it is also possible to perform quantitative analysis of the concentration of the chelating agent by measuring the colorimetric response. In this paper, five types of chelating agents were used, including EDTA, EGTA, NTA, DCTA and DTPA. Among them, EDTA and DCTA triggered especially strong color-transition. In conclusion, this study has led to a successful development of a color transition-based PDA sensor system for easy and rapid detection of chelating agents.

Separation of nickel from cobalt using cation exchange membranes in the presence of chelating agents

Selectivity of metals from aqueous solutions containing chelating agents such as EDTA (ethylenediaminetetraacetic acid), NTA (nitrilotriacetic acid) and citrate was studied in a two-chamber cell separating with a commercial cation-exchange membrane (CEM). In the experiments, equimolar solutions of metal and chelating agent as an anolyte and acid solutions as a catholyte were used, the effect of current density, type of solvent, concentration of catholyte and anolyte solution, type of chelating agent, type of the cation-exchange membrane on the selectivity for metals were determined. The obtained results show that this membrane technique, classified as electrodeposition and electrodialysis, seems to be an applicable method for the selectivity of metals under appropriate conditions.

Effect of Ethylenediaminetetraacetic Acid on Growth and Phytoremediative Ability of Two Wheat Varieties

Chelating agents are commonly used to enhance the phytoremediative ability of plants. The type of chelating agent applied and the selection of plant species are important factors to consider for successful phytoremediation. This study investigates the effects of four different rates (0, 2, 4, 8 mmol kg−1) of ethylenediaminetetraacetic acid (EDTA) on lead (Pb) dissolution, plant growth, and the ability of two spring wheat varieties (Auqab-2000 and Inqalab-91) to accumulate Pb from contaminated soils in a pot study. The results indicated that the addition of EDTA to the soil significantly increased the aqueous solubility of Pb and that wheat variety Inqalab-91 was more tolerant to Pb than Auqab-2000. Application of EDTA at 8 mmol kg−1 resulted in biomass yield, photosynthetic rate, and transpiration rate significantly lower in Auqab-2000 than in Inqalab-91. Although EDTA enhanced the uptake of Pb by both wheat varieties, Auqab-2000 accumulated significantly more Pb in the shoots than Inqalab-91. The results of the present study suggest that under the conditions used in this experiment, EDTA at the highest dose was the best amendment for enhanced phytoextraction of Pb using wheat. High concentrations of Pb were found in leachates collected from the bottom of columns treated with EDTA. Application of EDTA in the column leaching experiment increased the concentration of Pb in leachate with increasing EDTA dosage (0–8 mmol kg−1). These results suggest that EDTA addition for enhancing soil cleanup must be designed properly to minimize the uncontrolled release of metals from soils into groundwater.

Recovery of palladium from spent catalyst with supercritical CO 2 and chelating agent

A system designed to efficiently recover palladium (Pd) from palladium-based catalysts using supercritical carbon dioxide (scCO 2) and a chelating agent has been investigated. The scCO 2 extraction of Pd directly from a spent Pd-based solid catalyst is reported. The scCO 2 was modified with chelating agents in order to bind Pd from the solid matrix. The effects of pressure, temperature, extraction time, scCO 2 density, and the type of chelating agent on the extraction efficiency of Pd were considered. Findings suggested that among the studied chelating agents of acetyl acetone (AA), tri- n-butyl phosphate/nitric acid complex (TBP/HNO 3/H 2O), and bis(2,2,4-trimethylpentyl)monothiophosphinic acid (Cyanex 302), Cyanex 302 was the best ligand for the extraction of Pd. At pressures ranging from 8 to 20 MPa and temperatures ranging from 313 to 353 K and a 10 min dynamic extraction time, Pd was successfully recovered from the solid matrix with an extraction efficiency of almost 100%. The extraction efficiencies for AA and TBP/HNO 3/H 2O were around 80 and 60%, respectively.

Sintering of Sio2-Tio2 obtained by the sol-gel process from chelated Ti precursors

Two experimental procedures were used to obtain SiO2-TiO2. In one case, the Si precursor was prehydrolyzed before reacting with Ti to equalize the chemical reactivity of both reagents. In the other case, H2O was produced in situ to avoid precipitation of TiO2. Two chelating agents were also used separately to control the polymerization process. It was found that the type of chelating agent leads to differences in the particle size.

Distinguishing between cellular and Fe-oxide-associated trace elements in phytoplankton

In cultures and in nature, ferric (oxyhydro-)oxides (FeO x ) precipitate and become associated with phytoplankton surfaces. Other trace elements adsorb on FeO x and it is thus difficult to differentiate between cellular- and oxide-associated concentrations of both iron and these elements. Existing techniques to selectively dissolve the FeO x associated with phytoplankton surfaces often contaminate the sample or necessitate elaborate pre-cleaning procedures and/or proceed by unknown and thus uncontrolled mechanisms. Here we examine the efficacy of various washing techniques, the mechanisms effecting FeO x dissolution, and the methods for controlling contamination from the wash solutions. Solutions containing a single chelating agent are ineffective at dissolving FeO x . A wash solution containing two types of chelating agents, oxalate and EDTA, is effective for dissolving fresh precipitates via a ligand-promoted process, in which oxalate and EDTA function synergistically. This is in contrast with a Ti–citrate–EDTA wash technique, which effectively dissolves fresh or aged FeO x by a reductive mechanism. Contaminating trace elements in the wash solutions that are complexed by excess EDTA can be effectively eliminated from filters by appropriate rinsing with a clean NaCl solution. For those elements that are not bound by excess EDTA, it is necessary to add specific chelating agents to the wash solution and, in some cases, to pre-clean the reagents. We show that under defined culture conditions, Ba and V in the diatom Thalassiosira weissflogii are mostly adsorbed on the extracellular FeO x so that their apparent cellular concentrations increase with the concentration of Fe in the culture medium. In contrast, the cellular concentrations of Cu, Zn, Co, Cd, and Mn, which are dominated by their intracellular pools, are independent of the Fe concentration in the medium and can be measured directly on rinsed filters without dissolving the FeO x .

Supercritical Fluid Extraction of Hazardous Metals from Urban Total Suspended Particles

This paper describes the procedure for supercritical fluid extraction (SFE) of hazardous metals (Cu, Pb, Zn, Cd, Cr, and Ni) from urban total suspended particles (TSP) with supercritical CO2 and several different types of chelating agents, under optimum extraction conditions of 20MPa, 60°C, and surfactant‐methanol modified supercritical CO2. Efficient extraction of metal ions from simulate samples was achieved. Only trifluoracetylacetone (TFA) is a general chelating agent to efficiently extract all of the target metal ions from TSP (83.2–99.3%). Sodium diethyldithiocarbamate (NaDDTC) can extract Cu, Pb, Zn, and Cd effectively (80.6–94.9%). 8‐Hydryquinoline (8‐HOx) can selectively extract Cu and Zn, with recoveries of 90.1% and 78.7%, respectively. Dithizone (H2Dz) is capable of extracting Cu, Zn, and Cr with recoveries of 93.8, 79.8, and 94.5%, respectively. The results showed that, under optimized extraction conditions, and with suitable selection of chelating agent, SFE for pretreating metals in TSP can yield results comparable to chemical digestion methods much more quickly and conveniently.