Showing papers on "Hydrofluoric acid published in 2007"
TL;DR: In this article, the potentiodynamic polarization technique was used to investigate the anodic behavior of the uncoated and coated magnesium alloy in borate buffer solution, and the experimental results showed that coating film density and corrosion resistance of stannate-coated samples prepared with pickling pretreatment were improved compared with those of the coated sample without pickling prereatment.
Abstract: Hydrofluoric and hydrochloric acid solutions and a mixture of them were tested as pickling solutions for AZ91 D Mg alloy before application of stannate coatings. Optical microscopy and energy dispersive X-ray spectroscopy (EDX) of the alloy surface after the pickling process showed that the Mg-rich α phase dissolved preferentially rather than the Al-rich β phase in hydrochloric acid solution. On the other hand, in hydrofluoric acid solution, Mg dissolved in a form of pitting corrosion. Pickling pretreatment with a mixture of these acids at an optimal concentration and an optimal pickling time resulted in relatively uniform dissolution of the alloy surface. The potentiodynamic polarization technique was used to investigate the anodic behavior of the uncoated and coated magnesium alloy in borate buffer solution. The morphology of the coatings was observed using a scanning electron microscope (SEM) before and after corrosion tests. The experimental results showed that coating film density and corrosion resistance of stannate-coated samples prepared with pickling pretreatment were improved compared with those of the coated sample without pickling pretreatment.
82 citations
Patent•
24 Oct 2007TL;DR: In this paper, a method of manufacturing a solar cell having a texture on a surface of a silicon substrate has been proposed, which includes a first process of forming a porous silicon layer on the surface of the silicon substrate by dipping the substrate into a mixed aqueous solution of an oxidizing reagent containing a metal ion and hydrofluoric acid.
Abstract: A solar cell manufacturing method provides a method of manufacturing a solar cell having a texture on a surface of a silicon substrate, to obtain the solar cell manufacturing method capable of manufacturing a solar cell of high performance in a simple manufacturing process. The solar cell manufacturing method includes a first process of forming a porous silicon layer on the surface of the silicon substrate by dipping the silicon substrate into a mixed aqueous solution of an oxidizing reagent containing a metal ion and hydrofluoric acid, and a second process of forming a texture by etching the surface of the silicon substrate after passing the first process, by dipping the silicon substrate into a mixed acid mainly containing hydrofluoric acid and nitric acid.[r]A method of manufacturing a solar cell having a texture on a surface of a silicon substrate includes first forming including forming a porous layer on the surface of the silicon substrate by dipping the silicon substrate into a mixed aqueous solution of oxidizing reagent containing metal ions and hydrofluoric acid; and second forming including forming a texture by etching the surface of the silicon substrate after the first forming by dipping the silicon substrate into a mixed acid mainly containing hydrofluoric acid and nitric acid.
33 citations
TL;DR: In this article, silicon 100 wafers, predipped in 1:20 v/v HF water, were treated separately with four different acid mixtures, viz., HNO3, H2SO4-H2O2, HNO 3-HF, and H 2SO4−HF, for different time durations, and then vigorous rinsing with deionized water rendered the wafer surfaces with hydroxyl termination.
Abstract: Silicon 100 wafers, predipped in 1:20 v/v HF water, were treated separately with four different acid mixtures, viz., HNO3, H2SO4–H2O2, HNO3–HF, and H2SO4–H2O2–HF, for different time durations. Subsequent vigorous rinsing with deionized water rendered the wafer surfaces with hydroxyl termination. Synthesized surfaces were characterized by diffuse-reflectance infrared Fourier transform spectroscopy DRIFTS, ellipsometry, contact angle and atomic force microscopy. Surfaces treated with HNO3
32 citations
Patent•
24 Oct 2007TL;DR: In this article, a method of manufacturing a solar cell having a texture on a surface of a silicon substrate includes first forming a porous layer on the surface of the silicon substrate by dipping the substrate into a mixed aqueous solution of oxidizing reagent containing metal ions and hydrofluoric acid.
Abstract: A method of manufacturing a solar cell having a texture on a surface of a silicon substrate includes first forming a porous layer on the surface of the silicon substrate by dipping the silicon substrate into a mixed aqueous solution of oxidizing reagent containing metal ions and hydrofluoric acid. Second, a texture is formed by etching the surface of the silicon substrate after the porous layer is formed, by dipping the silicon substrate into a mixed acid mainly containing hydrofluoric acid and nitric acid.
31 citations
TL;DR: In this article, the chemical etch rate of a commercial photosensitive glass ceramic (FoturanTM, Schott Corp., Germany) in dilute hydrofluoric acid is strongly dependent on the incident laser irradiance during patterning at λ =266 nm and λ=355 nm.
Abstract: Previous studies in our laboratory have reported that the chemical etch rate of a commercial photosensitive glass ceramic (FoturanTM, Schott Corp., Germany) in dilute hydrofluoric acid is strongly dependent on the incident laser irradiance during patterning at λ=266 nm and λ=355 nm. To help elucidate the underlying chemical and physical processes associated with the laser-induced variations in the chemical etch rate, several complimentary techniques were employed at various stages of the UV laser exposure and thermal treatment. X-ray diffraction (XRD) was used to identify the crystalline phases that are formed in Foturan following laser irradiation and annealing, and monitor the crystalline content as a function of laser irradiance at λ=266 nm and λ=355 nm. The XRD results indicate the nucleation of lithium metasilicate (Li2SiO3) crystals as the exclusive phase following laser irradiation and thermal treatment at temperatures not exceeding 605 °C. The XRD studies also show that the Li2SiO3 density increases with increasing laser irradiance and saturates at high laser irradiance. For our thermal treatment protocol, the average Li2SiO3 crystal diameters are 117.0±10.0 nm and 91.2±5.8 nm for λ=266 nm and λ=355 nm, respectively. Transmission electron microscopy (TEM) was utilized to examine the microscopic structural features of the lithium metasilicate crystals. The TEM results reveal that the growth of lithium metasilicate crystals proceeds dendritically, and produces Li2SiO3 crystals that are ∼700–1000 nm in length for saturation exposures. Optical transmission spectroscopy (OTS) was used to study the growth of metallic silver clusters that act as nucleation sites for the Li2SiO3 crystalline phase. The OTS results show that the (Ag0)x cluster concentration has a dependence on incident laser irradiance that is similar to the etch rate ratios and Li2SiO3 concentration. A comparison between the XRD and optical transmission results and our prior etch rate results show that the etch rate contrast and absolute etch rates are dictated by the Li2SiO3 concentration, which is in turn governed by the (Ag0)x cluster concentration. These results characterize the relationship between the laser exposure and chemical etch rate for Foturan, and permit a more detailed understanding of the photophysical processes that occur in the general class of photostructurable glass ceramic materials. Consequently, these results may also influence the laser processing of other photoactive materials.
28 citations
Patent•
21 Feb 2007TL;DR: In this article, the etch solutions are formulated as a mixture of hydrofluoric acid and an organic acid having a dielectric constant less than water, optionally with an inorganic acid, and a pH of 1 or less.
Abstract: Etch solutions for selectively etching doped oxide materials in the presence of silicon nitride, titanium nitride, and silicon materials, and methods utilizing the etch solutions, for example, in the construction of container capacitor constructions is provided. The etch solutions are formulated as a mixture of hydrofluoric acid and an organic acid having a dielectric constant less than water, optionally with an inorganic acid, and a pH of 1 or less.
27 citations
TL;DR: In this article, a self-consistent reaction field polarized continuum model was applied to verify the behavior of the C 2 H 4 O-HF heterocyclic hydrogen bonded complex in aqueous media in comparison to the gas phase by means of several parameters, such as intermolecular distance, Gibbs free energy and dipole moment.
Abstract: Continuum and discrete models were combined for describe the solvent effects on the hydrogen bonded complex formed by ethylene oxide and hydrofluoric acid. In terms of continuum models, we applied the self-consistent reaction field polarized continuum model to verify the behavior of the C 2 H 4 O–HF heterocyclic hydrogen bonded complex in aqueous media in comparison to the gas phase by means of several parameters, such as intermolecular distance, Gibbs free energy and dipole moment. However, as widely known that continuum models are limited for describe adequately specific interactions between solute and solvent, the new AGOA methodology supply this hindrance by determining hydration clusters around the solute molecule. Based on the analysis of the molecular electrostatic potential of the solute (C 2 H 4 O–HF), the AGOA provided hydration clusters from optimized geometry using B3LYP/6-311++G(d,p) calculations. The result obtained justifies satisfactorily the acid catalyzed open ring reactions of the ethylene oxide because the preferential nucleophilic water attack occurs on the methyl groups of the three-membered ring, whose interaction energies values had reached up to −292.0 kJ mol −1 .
26 citations
TL;DR: In this article, the electret properties of virginal cellular polypropylene (PP) films and chemically modified cellular PP films by extraction from CH 2 Cl 2 solution, oxidation in a mixture solution of H 2 SO 4, CrO 3 and H 2 O and fluorination in a hydrofluoric acid (HF) solution, were systematically studied by measuring the open-circuit thermally stimulated discharge (TSD) current spectra, charge TSD spectra and isothermal charge decay.
25 citations
Patent•
06 Jun 2007
TL;DR: The nanometer porous WO3 material has high photocatalytic capacity and is one kind of high efficiency photocatalyst as mentioned in this paper, it is formed through molecule self-assembling and with homogeneous structure, pore diameter of 60-150 nm, regular arrangement and face oriented monoclinic system structure.
Abstract: The present invention relates to nanometer porous WO3 material, and is especially nanometer porous WO3 material formed through molecule self-assembling and with homogeneous structure, pore diameter of 60-150 nm, regular arrangement and (002) face oriented monoclinic system structure. The nanometer porous WO3 material is prepared through a constant current anode oxidation process with metal W substrate and electrolyte solution, which consists of inorganic fluoride sodium fluoride, potassium fluoride or ammonium fluoride and inorganic strong acid hydrofluoric acid, hydrochloric acid or sulfuric acid and has F- ion concentration of 0.05-0.3 mol/L and H+ ion concentration of 0.05-0.5 mol/L. The nanometer porous WO3 material has high photocatalytic capacity and is one kind of high efficiency photocatalyst.
22 citations
TL;DR: In this article, the results from an experimental study of the purification of dilute hydrofluoric acid (5.9% HF) by ion exchange were presented. But the results of this study were limited to two columns containing commercial cation and anion resins from Dow, Bayer and Rohm and Haas companies.
22 citations
TL;DR: In this article, the effect of the acetic acid content in the starting solution, and the substrate temperature on the electrical resistivity, structure, morphology and optical characteristics was studied.
TL;DR: Two methods for the total analysis of the individual etch bath constituents HF, HNO(3), and H(2)SiF(6) are described, based on the determination of the total fluoride concentration using a fluoride ion-selective electrode (F-ISE).
TL;DR: In this article, the authors investigated the degradation of ferrocolumbite with hydrofluoric acid solutions in a pressure reactor and found that the leaching rate of the mineral increases with the concentration of acid and the reaction temperature but is not affected very much by stirring speed.
TL;DR: In this article, the authors reported the formation of porous silicon (PS) by application of a positive potential on n-type silicon without illumination in 1-ethyl-3methylimidazolium oligofluorohydrogenate [EtMeIm(FH) 2.3 F] room-temperature ionic liquid.
Abstract: This communication reports the formation of porous silicon (PS) by application of a positive potential on n-type silicon without illumination. PS films were formed in 1-ethyl-3-methylimidazolium oligofluorohydrogenate [EtMeIm(FH) 2.3 F] room-temperature ionic liquid, and the surface morphology strongly depended on the time and the applied potential. The results indicate that EtMeIm(FH) 2.3 F could be a nonaqueous solvent equivalent to hydrofluoric acid, allowing the formation of pores under anodic polarization.
Patent•
07 Nov 2007
TL;DR: In this paper, the synthesis process of high nitrogen doped corrugated carbon nanotube material and its synthesis process is described, which includes the following steps: mixing Fe source and proper amount of distilled water, soaking porous molecular sieve to carry ferric oxide or ferrous oxide, stoving and roasting at 300-1000 deg.c for 0.5-24 hr to obtain catalyst; setting the catalyst inside a pipe furnace, leading organic amine into the furnace under the protection of Ar or N2 and reacting at 650- 1000 deg. c for 0
Abstract: The present invention relates to high nitrogen doped corrugated carbon nanotube material and its synthesis process. The synthesis process includes the following steps: mixing Fe source and proper amount of distilled water, soaking porous molecular sieve to carry ferric oxide or ferrous oxide, stoving and roasting at 300-1000 deg.c for 0.5-24 hr to obtain catalyst; setting the catalyst inside a pipe furnace, leading organic amine into the furnace under the protection of Ar or N2 and reacting at 650-1000 deg.c for 0.2-4.0 hr to obtain high nitrogen doped corrugated carbon nanotube mixture containing the catalyst; soaking the mixture in proper amount of or excessive hydrofluoric acid, sulfuric acid, nitric acid or acid for 0.5-24 hr; and washing in distilled water, suction filtering and drying to obtain high nitrogen doped corrugated carbon nanotube material. The material has nitrogen content of 10-40 %, reinforced surface polarity, etc, and is suitable for industrial production.
Patent•
13 Jun 2007
TL;DR: In this paper, a washing agent used in rinsing a strainer plate is described, which can deal with mixed dirt such as carbonate, silicate, sulphate, phosphate, sulphide and hydroxid.
Abstract: This invention relates to a washing agent used in rinsing ceramic strainer plate. According to the weight percentage, it contains the following materials: nitric acid 0.1~5%; hydrochloric acid 0.1~5%; hydrofluoric acid 0.2~3%; oxalic acid 0.1~5%. By the combined action of nitric acid, hydrochloric acid and hydrofluoric acid, it can deal with the mixed dirt such as carbonate, silicate, sulphate, phosphate, sulphide and hydroxid, and so on. The washing effectiveness is good and the scope of application is extensive. Otherwise, it can enhance the operating life of strainer plate and can extend the serviceable range of ceramic filtering machine.
Patent•
18 Sep 2007TL;DR: The productivity of hydrocarbons from hydrocarbon-bearing calcareous or siliceous formations is enhanced by contacting the formation with a well treatment composition which contains a hydrofluoric acid source, a boron containing compound and a phosphonate acid, ester or salt thereof as discussed by the authors.
Abstract: The productivity of hydrocarbons from hydrocarbon-bearing calcareous or siliceous formations is enhanced by contacting the formation with a well treatment composition which contains a hydrofluoric acid source, a boron containing compound and a phosphonate acid, ester or salt thereof.
TL;DR: In this article, the formation of intermolecular interactions on heterocyclic hydrogen-bonded complexes formed by ethylene oxide, sulfide oxide, 2,5-dihydrofuran, thiophene, and the hydrofluoric acid was investigated.
Abstract: B3LYP/6-311++G(d,p) and B3LYP/6-31G(d,p) theoretical levels combined with topological calculations based on the theory of atoms in molecules (AIM) were used to study the formation of intermolecular interactions on heterocyclic hydrogen-bonded complexes formed by ethylene oxide, sulfide oxide, 2,5-dihydrofuran, thiophene, and the hydrofluoric acid As observed, the electrophilic attack of the hydrofluoric acid occur aligned to the n lone pair of the heteroatom of the cyclic systems, the modeled structure of the hydrogen-bonded complexes is interpreted in terms of the intermolecular parameters of the (n ⋯ HF) hydrogen bond, such as its R(n ⋯ HF) distance, ΔEC binding energy, and the new υ(n ⋯ HF) stretching vibrational mode From these criteria, a relationship between the strength (R, ΔEC and υ) of the hydrogen bonds and its nonlinearity deviation was verified, which is formed by a secondary interaction between the hydrofluoric acid and axial hydrogen atoms of the cyclic structure Moreover, even though the Bader's electronic density partitioning has been projected with low dependence from ab initio wave functions, it is shown here that the 6-31G(d,p) basis sets characterized the secondary interaction in geometrical point of view, as well as by means of the AIM protocol through the specific calculation of bond critical points between the fluoride and the axial hydrogen atoms
Patent•
01 Feb 2007
TL;DR: In this article, the authors proposed a method and an apparatus for separating/recovering recyclable hydrofluoric acid and silicofluoric acid efficiently from a waste liquid containing HFOs and SFOs.
Abstract: PROBLEM TO BE SOLVED: To provide a method and an apparatus for separating/recovering recyclable hydrofluoric acid and silicofluoric acid efficiently from a waste liquid containing hydrofluoric acid and silicofluoric acid. SOLUTION: The method comprises separating the solid in the waste liquid containing hydrofluoric acid and silicofluoric acid and then first concentrating the waste liquid by distillation, and recovering an aqueous solution containing mainly hydrofluoric acid and an aqueous solution containing mainly silicofluoric acid, respectively. Other materials are remained in the distillation pot residue. The aqueous solution containing hydrogen fluoride can be recycled as a chemical etching treatment liquid for glass after adjusting the concentration by adding hydrofluoric acid. The aqueous solution containing silicofluoric acid can be recycled as synthetic raw materials of silicofluoric acid and silicofluoride for sales on the market by converting the hydrofluoric acid to silicofluoric acid by adding silicon dioxide and further by adjusting the concentration to a given one by diluting it with water. COPYRIGHT: (C)2008,JPO&INPIT
TL;DR: The determination of 52 impurity elements in niobium materials was performed by inductively coupled plasma mass spectrometry (ICP-MS) with on-line anion exchange matrix separation as well as direct nebulization.
Patent•
05 Sep 2007
TL;DR: A high-purity diamond powder used for grinding and polishing the monocrystal wafer, IC board, or hard disc is prepared from the superfine diamond powder prepared by static pressure synthesis or explosion through wet-type chemical treating by nitric acid, perchloric acid, and hydrofluoric acid, washing with purified water, and drying.
Abstract: A high-purity superfine diamond powder used for grinding and polishing the monocrystal wafer, IC board, or hard disc is prepared from the superfine diamond powder prepared by static pressure synthesis or explosion through wet-type chemical treating by nitric acid, perchloric acid, and hydrofluoric acid, washing with purified water, and drying.
Patent•
14 Nov 2007
TL;DR: In this paper, a surface-treated metal material comprising a composite coating film which is obtained by applying an aqueous metal surface treatment agent over the surface of a metal material and drying the agent thereon is described.
Abstract: Disclosed is a surface-treated metal material comprising a composite coating film which is obtained by applying an aqueous metal surface treatment agent over the surface of a metal material and drying the agent thereon. The aqueous metal surface treatment agent is composed of an organosilicon compound (W) obtained by blending a silane coupling agent (A) having one amino group in a molecule and a silane coupling agent (B) having one glycidyl group in a molecule at a solid content mass ratio [(A)/(B)] of 0.7-1.7, at least one fluorocompound (X) selected from titanium hydrofluoric acid and zirconium hydrofluoric acid, phosphoric acid (Y), a vanadium compound (Z) and a lubricating agent (J).
Patent•
18 Sep 2007TL;DR: The productivity of hydrocarbons from hydrocarbon-bearing calcareous or siliceous formations is enhanced by contacting the formation with a well treatment composition which contains a hydrofluoric acid source, a boron containing compound and a phosphonate acid, ester or salt thereof as discussed by the authors.
Abstract: The productivity of hydrocarbons from hydrocarbon-bearing calcareous or siliceous formations is enhanced by contacting the formation with a well treatment composition which contains a hydrofluoric acid source, a boron containing compound and a phosphonate acid, ester or salt thereof.
Patent•
19 Feb 2007
TL;DR: In this paper, an analysis method of the trace of metal is characterized by mixing an acid with the hydrocarbon oil, when determining the traces of metal less than 1 ppm included in the hydrocarbons by either ICP emission analysis or by ICP mass spectrometry.
Abstract: PROBLEM TO BE SOLVED: To provide an analysis method capable of measuring precisely and highly accurately, when determining a trace of metal in a hydrocarbon oil by ICP emission analysis or by ICP mass spectrometry. SOLUTION: This analysis method of the trace of metal is characterized by mixing an acid with the hydrocarbon oil, when determining the trace of metal less than 1 ppm included in the hydrocarbon oil by the ICP emission analysis or by the ICP mass spectrometry. In this case, as the acid, an acid is preferably used, which is selected from nitric acid, hydrochloric acid, sulphuric acid, hydrofluoric acid, phosphoric acid, perchloric acid, acetic acid, and formic acid. COPYRIGHT: (C)2008,JPO&INPIT
TL;DR: In this paper, graphite intercalation compounds (GICs) of composition C x N(SO 2 CF 3 ) 2 ǫ · δ F are prepared under ambient conditions in 48% hydrofluoric acid, using K 2 MnF 6 as an oxidizing reagent.
Patent•
09 Aug 2007
TL;DR: In this article, a method for treating fluorine-containing liquid waste comprises the steps of: adding a calcium-containing substance to the fluorine containing liquid waste containing a fluorine ion and the heavy metal ion to precipitate calcium fluoride-based particles (a particle precipitation step); adding a polymer flocculant to the calcium-based particle-precipitated liquid to produce flocks of calcium fluoride based particles; and subjecting the flock-produced liquid to solid-liquid separation to recover calcium fluoridebased particles as a solid portion.
Abstract: PROBLEM TO BE SOLVED: To provide a method for treating fluorine-containing liquid waste, in which calcium fluoride and metal hydroxide, which are precipitated at a step of neutralizing fluorine-containing liquid waste containing a fluorine ion and a heavy metal ion, are separated from each other and the former is used satisfactorily in the iron industry as a slag formation promoting agent or an alternative raw material of fluorite being a raw material of hydrofluoric acid and the latter is used satisfactorily in the iron industry as a raw material for stainless steel. SOLUTION: The method for treating fluorine-containing liquid waste comprises the steps of: adding a calcium-containing substance to the fluorine-containing liquid waste containing the fluorine ion and the heavy metal ion to precipitate calcium fluoride-based particles (a particle precipitation step); adding a polymer flocculant to the calcium fluoride-based particle-precipitated liquid to produce flocks of calcium fluoride-based particles; and subjecting the flock-produced liquid to solid-liquid separation to recover calcium fluoride-based particles as a solid portion. A part of the recovered solid portion is returned at the particle precipitation step to further precipitate calcium fluoride on the precipitated calcium fluoride-based particles and increase the particle size thereof and the calcium fluoride-based particles having the increased particle size are recovered as the solid portion by the solid-liquid separation. COPYRIGHT: (C)2007,JPO&INPIT
Patent•
13 Mar 2007TL;DR: In this paper, the surface of a metallic glass component is reacted with a mixed aqueous solution of nitric acid and hydrofluoric acid to remove an oxide film and to provide an anchor bond shape on the surface.
Abstract: There is provided a metallic glass component with its surface layer having both durability of a film and chromatic color properties, and a method for forming the surface layer. Surface active treatment is performed wherein the surface of the metallic glass component is reacted with a mixed aqueous solution of nitric acid and hydrofluoric acid to remove an oxide film and to provide an anchor bond shape on the surface of a metallic glass component, and electroplating or electroless plating is then performed, to form a plating film on the surface of the metallic glass component. It is thereby possible to form a surface layer of a metallic glass which has both durability and a chromatic color.
Patent•
24 May 2007
TL;DR: In this article, a method for treating chelating agent-containing water with fluorine and phosphorus is presented. But the method is not suitable for the treatment of water containing a chelation agent.
Abstract: PROBLEM TO BE SOLVED: To provide a method and an apparatus for treating chelating agent-containing water with fluorine and phosphorus, in which water containing a chelating agent is subjected to Fenton treatment before the chelating agent-containing water is treated with fluorine and phosphorus, to form a calcium compound stably, so that the amount of sludge to be generated is reduced and higher-quality treated water is obtained. SOLUTION: The method for treating the chelating agent-containing water with fluorine and phosphorus comprises: a insolubilized material formation step of reacting the calcium compound with raw water containing the chelating agent and hydrofluoric acid and/or phosphorus to form an insolubilized material; and a solid-liquid separation step of subjecting the formed insolubilized material to solid-liquid separation to obtain treated water. Such a step that raw water is subjected to Fenton treatment in the presence of a ferrous ion and H 2 O 2 , is arranged substantially before the insolubilized material formation step. COPYRIGHT: (C)2007,JPO&INPIT
Patent•
25 Sep 2007
TL;DR: In this paper, the authors proposed a method to solve the problems wherein the flaws or the like on a glass surface are enlarged and flatness is deteriorated in a chemical polishing step for reducing the thickness of a glass substrate for a liquid crystal display device.
Abstract: PROBLEM TO BE SOLVED: To solve the problems wherein the flaws or the like on a glass surface are enlarged and flatness is deteriorated in a chemical polishing step for reducing the thickness of a glass substrate for a liquid crystal display device. SOLUTION: The enlargement of the flaws is suppressed and the liquid crystal display element having an excellent display surface quality is efficiently manufactured at a low cost by polishing a glass substrate surface by a chemical polishing liquid containing at a ratio of ≥25 wt.% mixture solution of hydrofluoric acid and ammonium fluoride and ≤30 wt.% at least one kind acid solution among hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid and acetic acid and using water as a solvent. COPYRIGHT: (C)2009,JPO&INPIT
Patent•
20 Feb 2007
TL;DR: In this paper, a method for assaying copper in silicon wafers is described, which includes the steps of forming a polysilicon layer on the surface of a p-type silicon wafer having the same characteristics as the silicon Wafers being assayed.
Abstract: This method for assaying copper in silicon wafers includes the steps of: forming a polysilicon layer on the surface of a p-type silicon wafer having the same characteristics as the silicon wafers being assayed; heat treating the p-type silicon wafer after it has been polished; dissolving the polysilicon layer on the heat-treated p-type silicon wafer with a mixed acid composed of at least hydrofluoric acid and nitric acid; and quantitatively determining the copper components within the mixed acid following dissolution of the polysilicon layer.