Copper removal

Turanose Phenylosotriazole. A solution of 15 g. of turanose phenylosazone in 300 cc. of hot water was placed on the steam-bath and a solution of 22 g. of copper siilfate pentahydrate in 150 cc. of hot water was added. The mixture turned a deep cherry-red at once and in a short time (fifteen min.) a red precipitate had formed and the solution had become green. After thirty minutes from the time of addition of the copper solution, the solution was cooled, filtered, and the copper removed as sulfide. The clear light yellow filtrate was neutralized with 45 g. of barium carbonate and the insoluble material removed by filtration. The filtrate was extracted with five 50-cc. portions of ether to remove the aniline, and the aqueous portion was concentrated in vacuo to a thick sirup. The sirup was dissolved in 60 cc. of warm alcohol, filtered to remove a slight turbidity and diluted with 65 cc. of ether. Upon cooling and scratching, the product crystallized as large prisms yield 8.9 g. (72%). The phenylosotriazole was recrystallized from 10 parts of alcohol and when pure showed the melting point 193-194° and rotated [a Jj" + 74.5° in aqueous solution (c, 0.90). 

Hall C, Wales DS, Keane MA (2001) Copper removal from aqueous systems biosorption by Pseudomonas syringae. Separ Sci Technol 36(2) 223-240 Haas JR, Dichristina TJ, Wade R Jr (2001) Thermodynamics of U(VI) sorption onto Shewanellaputrefaciens. Chem Geol 180 33-54 He LM, Tebo BM (1998) Surface charge properties of and Cu(II) adsorption by spores of the marine Bacillus sp. strain SG-1. Appl Environ Microbiol 64 1123-1129... 

In a method described by Bates and Carpenter [8] for the characterization of organosulphur compounds in the lipophilic extracts of marine sediments these workers showed that the main interference is elemental sulphur (S8). Techniques for its elimination are discussed. Saponification of the initial extract is shown to create organosulphur compounds. Activated copper removes S8 from an extract and appears neither to create nor to alter organosulphur compounds. However, mercaptans and most disulphides are removed by the copper column. The extraction efficiency of several other classes of sulphur compounds is 80-90%. Extracts are analyzed with a glass capillary gas chromatograph equipped with a flame photometric detector. Detection limit is lg S and precision 10%. 

SOD, isolated from bovine erythrocytes, is a blue-green protein due to the presence of copper, removal of which by treatment with EDTA results in loss of activity, which is restored by adding Cu2+ it also contains Zn2+, which does not appear to be at the active site. The enzyme, which is very stable in 9 M urea at neutral pH, consists of two identical subunits of molecular weight 16kDa held together by one or more disulphide bonds. The amino acid sequence has been established. 

Solids separation in the settlement basin controlled the removal of metals in the pilot plant, because removal efficiency varied Inversely with flow rate at the roughly constant level of neutralization attained, e.s., Table 2 shows a 72% mean copper removal for the 28 gpm mean high flow, versus 93% mean removal at the mean 1.6 gpm swan low flow. On this basis, effluent copper varies with flow rate raised to the 0.33 power, because ... 

Peerson, F., "Neutralization-Clarification Tradeoff In Copper Removal," submitted to Journal of the Water Pollution Control Federation. 

Modeling and optimization of MBSE and MBSS of a multicomponent metallic solution in HF contactors is discussed in ref. [77]. A short-cut method for the design and simulation of two-phase HF contactors in MBSE and MBSS with the concentration-dependent overall mass-transfer and distribution coefficients taking into account also reaction kinetics was suggested by Kertesz and Schlosser [47]. Comparison of performance of the MBSE and MBSS circuit with pertraction through ELM in case of phenol removal presented Reis [78] and for copper removal Gameiro [79]. 

Yang, Q. and Kocherginsky, N.M. (2007) Copper removal from ammoniacal wastewater through a hollow fiber supported liquid membrane system Modeling and experimental verification. Journal of Membrane Science, 297, 121. 

CEER process — (Capenhurst electrolytic etchant regeneration process) Electrochemical process for continuous copper removal from printed circuit board etching solutions employing either cupric chloride or ammoniacal etchant. In a cell divided by a cation exchange membrane the etching process is essentially reversed. In case of the cupric chloride etchant the etchant solution is pumped to the anode, the processes are at the... 

In the CEER cell the etchant is pumped to the cathode where copper removal proceeds. 

The metal ions sequentially removed from the acid/alkali solutions were silver, copper, chromium(III), and cadmium/nickel. The cadmium and nickel were later separated from each other. The first separation performed with the chrome solution involved the selective separation of Cr(VI) as C1O4 from the feed solution. Chromium(III) remained in the solution in small amounts after Cr(VI) was removed. Neither the Cr(VI) nor the Cr(III) SuperLig material is capable of removing the other chromium species. The second separation from the chrome solution involved copper removal. The third separation was the removal of the remaining chromium as Ciflll). The final separation was the removal of nickel. 

Du T, Tamboli D, Desai V, Seal S. Mechanism of copper removal during CMP in acidic H2O2 slurry. J Electrochem Soc 2004 151G231-G235. 

The chemical component of CMP slurry creates porous unstable oxides or soluble surface complexes. The slurries are designed to have additives that initiate the above reactions. The mechanical component of the process removes the above-formed films by abrasion. In most planarization systems the mechanical component is the rate-limiting step. As soon as the formed porous film is removed, a new one is formed and planarization proceeds. Therefore, the removal rate is directly proportional to the applied pressure. To achieve practical copper removal rates, pressures greater than 3 psi are often required. These pressures should not create delamination, material deformation, or cracking on dense or relatively dense dielectrics used in silicon microfabrication on conventional dielectrics. However, the introduction of porous ultra-low-fc (low dielectric constant) materials will require a low downpressure (< 1 psi) polishing to maintain the structural integrity of the device [7-9]. It is expected that dielectrics with k value less than 2.4 will require a planarization process of 1 psi downpressure or less when they are introduced to production. It is expected that this process requirement will become even more important for the 45-nm technology node [10]. 

However, electropolishing is pattern sensitive and this may limit its applications. The passivation film or diffusion layer thickness is minimal above narrow features as the diffusion layer profile is unaffected by the copper surface profile. Therefore, the diffusion flux that corresponds to the removal rate is large for these features and planarization of these features is possible. For wide features, the diffusion layer profile follows the copper surface profile, the removal rate is low, and this leads to a conformal copper removal and inadequate planarization. 

Substituting for constants, the copper removal rate in pm/min is given by... 

The copper removal rates can be varied from 200 to 1700 nm/min. The removal rate is varied by altering the rotational speed and the water concentration. However, as mentioned, pattern sensitivity limits its application to planarization of integrated circuits. 

In order to control the removal profile on the wafer, a multizone cathode is used. Each of the three zones of the cathode is biased independently by a separate power supply as shown in Fig. 11.10. A five-zone cathode has also been reported to better control the wafer removal rate profile. Figure 11.11 shows that zone 1 is responsible for 60% of the amount of removed copper up to 100 mm radius the remaining 40% is coming from zone 2. The copper removal of the last 50 mm of the wafer is coming from a combination of the three zones. The net removal is a linear combination of the removal from each zone. 

ECMP, end point is based on the amount of charges delivered to each zone, which follows Faraday s law. There is a linear relationship between the charge required by each zone and the amount of copper removed. By modulating the charge on each zone as shown in Fig. 11.12, a desirable removal profile can be obtained. 

Manens et al. [27] reported that charge-based end-point detection coupled with advanced process control (APC) can be used to adjust the amount of copper removed and compensate for the large variations in incoming Cu thickness. Figure 11.13 shows wafers with various incoming Cu thicknesses ranging from 3500 A to more than 6000 A, which simulates, in an extreme fashion, the variations that can be observed from wafer-to-wafer and lot-to-lot... 

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