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WO2009053007A1 - Procédé et dispositif pour traiter un mélange servant d'abrasif constitué d'un milieu de dispersion thixotrope et de grains abrasifs - Google Patents

Procédé et dispositif pour traiter un mélange servant d'abrasif constitué d'un milieu de dispersion thixotrope et de grains abrasifs Download PDF

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Publication number
WO2009053007A1
WO2009053007A1 PCT/EP2008/008827 EP2008008827W WO2009053007A1 WO 2009053007 A1 WO2009053007 A1 WO 2009053007A1 EP 2008008827 W EP2008008827 W EP 2008008827W WO 2009053007 A1 WO2009053007 A1 WO 2009053007A1
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WO
WIPO (PCT)
Prior art keywords
mixture
dispersion medium
abrasive grains
sedimentation
water
Prior art date
Application number
PCT/EP2008/008827
Other languages
German (de)
English (en)
Inventor
Klaus Holtmann
Björn ZENNER
John G. Beesley
Original Assignee
S & B Industrial Minerals Gmbh
Meyer Burger Ag
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by S & B Industrial Minerals Gmbh, Meyer Burger Ag filed Critical S & B Industrial Minerals Gmbh
Publication of WO2009053007A1 publication Critical patent/WO2009053007A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
    • B03B5/00—Washing granular, powdered or lumpy materials; Wet separating
    • B03B5/28—Washing granular, powdered or lumpy materials; Wet separating by sink-float separation
    • B03B5/30—Washing granular, powdered or lumpy materials; Wet separating by sink-float separation using heavy liquids or suspensions
    • B03B5/44—Application of particular media therefor
    • B03B5/442—Application of particular media therefor composition of heavy media
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
    • B03B13/00—Control arrangements specially adapted for wet-separating apparatus or for dressing plant, using physical effects
    • B03B13/005—Methods or arrangements for controlling the physical properties of heavy media, e.g. density, concentration or viscosity
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B57/00—Devices for feeding, applying, grading or recovering grinding, polishing or lapping agents
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28D—WORKING STONE OR STONE-LIKE MATERIALS
    • B28D5/00—Fine working of gems, jewels, crystals, e.g. of semiconductor material; apparatus or devices therefor
    • B28D5/0058—Accessories specially adapted for use with machines for fine working of gems, jewels, crystals, e.g. of semiconductor material
    • B28D5/007—Use, recovery or regeneration of abrasive mediums
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/10—Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working

Definitions

  • the invention relates to a process for the preparation or separation of grains from a mixture of a dispersion medium and the abrasive particles concerned in the course of their use as abrasive for chip removal, in particular for the chip-removing separation of workpieces, preferably semiconductor crystals.
  • the core therefore is to separate the abrasive grains from the mixture. These grains act or act as a whole the mixture as an abrasive in chip removal machining.
  • wire saws or wire machines are generally used, which use a mixture (slurry) of the dispersion medium and the abrasive grains as abrasive , With the aid of this mixture, the cutting process is made possible only because the particles which are freely movable and abrasive in the mixture cause a lapping process associated therewith (see DE 195 38 612 A1).
  • a dispersion medium which consists of organic components, namely a hydrophilic polyhydric alcohol compound, a lipophilic polyhydric alcohol compound and water, is generally used.
  • colloidal silica particles prepared from a silicate are dispersed, as described in detail in DE 699 11 549 T2.
  • WO 2006/137098 A1 is a method for the reuse of such abrasively used in the lapping process. kender grains. For this purpose, hydrocyclones or centrifuges are used, which is relatively expensive. This is where the invention starts.
  • the invention is based on the technical problem of further developing such a method so that the procedural complexity is reduced and the costs of an associated device are minimized.
  • the dispersion medium used is based primarily on water as the dispersion medium, which as a rule represents a proportion of more than 85% by weight in the dispersion medium. It is furthermore of particular importance that the dispersion medium has a thixotropic behavior, ie a viscosity or viscosity which changes depending on the mechanical loading of the dispersion medium.
  • the viscosity of the thixotropic and substantially water-based dispersion medium according to the invention is generally adjusted so that the concentration of colloids or colloidal particles is dimensioned in the dispersion medium so that sedimentieren at dormant dispersion medium, the abrasive grains of desired grain size for their separation, whereas mostly Fine components are retained in the dispersion medium.
  • the thixotropic dispersion medium and the abrasive grains as abrasives form the overall mixture, which is used for chip-removing machining of workpieces and in particular for chip-removing separation of semiconductor crystals.
  • These semiconductor crystals are preferably rod-shaped or rod-shaped silicon monocrystals, which in the course of the chip-removing separation into slices desired size and previously set thickness (wafer) to be separated.
  • workpieces made of polysilicon can be processed.
  • those of other semiconductor materials such as gallium arsenide, gallium indium phosphite, etc ..
  • the dispersion medium with the abrasive grains dispersed therein is used for non-forming chip-removing machining.
  • This workpiece is, as already described and preferred, a semiconductor crystal, which is subdivided with the aid of the mixture in a corresponding chip-removing separation process in the desired thickness wafers (wafers), which are then usually still polished to order them for further process steps prepare.
  • the invention has surprisingly recognized that a thixotropic and substantially water-based dispersion medium known per se can advantageously be used with the grains dispersed therein as an additional phase and having abrasives as abrasives for the described chip-removing machining of workpieces, in particular of semiconductor crystals.
  • the thixotropic effect of the dispersion medium for the described application is of particular importance.
  • the dispersion medium has, according to an advantageous embodiment, charged colloidal particles. These charged colloidal particles form networks with sufficient concentration in the dispersion medium to each other and in the best case an elastic gel, which carries the abrasive grains permanently in itself.
  • the colloidal particles in the dispersion medium are smectites, ie layer silicates with a three-layer structure, which are preferably used. These are usually suspended in water as a dispersant. In this context, a high yield strength of the dispersant is crucial, with low viscosity under shear stress. This is basically known from DE 1 023 732.
  • the buoyancy of the particles to be sedimented is not changed by increasing the density of the dispersion medium in the mixture. Rather, the density and also the density of the dispersion medium remain essentially the same and the gel strength is merely adjusted by the addition of more or less colloidal particles.
  • the gel strength is a measure of the gelling ability of the gel, which can be determined using, for example, a Bousher gelling tester. The gel strength is generally measured in g / cm 2 or N / m 2 or in Pa or mPa. In any case, according to the invention, the gel strength is varied in order to selectively retain or sediment the abrasive grains in the gel which forms the abrasive grains, as will be explained in more detail below.
  • the dispersion medium about 1 wt .-% to 10 wt .-%, in particular about 1 wt .-% to 5 wt .-% and preferably about 2 wt .-% to 3 wt. -% of a clay mineral dissolved in water. That is, the dispersion medium is composed predominantly of water as the dispersant and the already mentioned clay mineral in the indicated concentration. The proportion of water is the dispersion medium usually more than 85% by weight.
  • the clay minerals used are preferably smectite-containing clays, for example bentonite, but also hectorite. In addition, other smectites such as corrensite, rectorite, saponite, stevensite, etc. are conceivable. These are known for the described thixotropic behavior. Basically both synthetic and natural clay minerals can be used.
  • Certain starches as well as organic polymers can advantageously be dissolved in water and used as the dispersion medium according to the invention.
  • acicular chain silicates such as sepiolite are able to form thixotropic aqueous suspensions.
  • these require very high solids content and the yield point is less well compared to the viscosity.
  • not only clay mineral colloidal particles are encompassed by the invention.
  • the thixotropic behavior of the clay mineral which is generally dissolved in the water, is brought about by the formation of bridges between the individual dissolved particles or smectites in such a clay mineral suspension without movement.
  • These bridges represent the already mentioned network, which carries the abrasive grains dispersed in the dispersion medium and prevents their sedimentation. This is achieved particularly simply by equipping the abrasive grains with particle sizes below 100 .mu.m, preferably less than 50 .mu.m and preferably below 20 .mu.m.
  • the abrasive grains are dispersed in the thixotropic dispersion medium, for example, with an average grain diameter of less than 100 ⁇ m, in particular below 50 ⁇ m, and preferably in the range of approximately 20 ⁇ m. Because such grain sizes can be easily record and hold in the described network.
  • the invention recommends in the dispersion medium in addition to the dispersant water as an additive, the clay mineral in low grain size with
  • Na and / or Li bentonites dissolved in water for the gelation can be used.
  • Particularly preferred synthetically produced hectorite has proven to be favorable, which although relatively expensive, but shows a very good thixotropic gelation.
  • the grain size of the clay mineral used is less than 200 microns and is more preferably below 100 microns and usually even below 50 microns or even below 20 microns. In this way, overall a relatively low viscosity of the mixture of the abrasive grains and the dispersion medium of water and the clay mineral additive is provided. In fact, inventively viscosities of mostly significantly less than 1 Pas (1 pascal-second) are observed. The viscosity is thus always below that of, for example, glycerol (1, 5 Pas).
  • the abovementioned described dynamic viscosity of the mixture is in the range of less than 500 mPas and is preferably below 400 mPas. Usually, a range between 30 and 350 mPas is observed depending on the proportion of abrasive grains for the mixture. As a result, low viscosities are available, which in particular for the production of slices of silicon single crystals (Silicon wafers) are particularly preferred. Because the mixture in question is usually used to rinse a wire, which cuts through the said silicon single crystal or generally the semiconductor crystal. It is usually worked with a low feed rate of about 0.1 mm / min, and set the cutting width in the range of below 0.2 mm. An example of such a separating device is described in DE 698 24 655 T2.
  • the method according to the invention is particularly suitable for first employing abrasively acting grains based on silicon carbide, boron carbide and / or diamond for the chip-removing machining and subsequently separating them from the mixture.
  • quartz, glass, ceramics, etc. can be processed in this way chip removal and in particular be subjected to a chip-removing separation.
  • the mixture according to the invention and used can be processed very easily.
  • the invention is based on the recognition that generally sedimentation processes, including the sedimentation of abrasive grains, obeys Stokes's law, according to which the rate of descent in a liquid (the dispersion medium) depends on the grain diameter, the density difference between the grain and the liquid and the viscosity of the liquid is dependent. By changing (increasing) the viscosity of large and heavy abrasive grains, their sinking speed can be reduced.
  • the dispersion medium according to the invention is not subjected to shear stress or mechanical loading, the already mentioned gel is formed.
  • a gel is an E-modulus solid.
  • the modulus of elasticity of the gel of the thixotropic and substantially water-based dispersion medium depends on the number and strength of the bonds of its colloids per unit volume. Thus, the type and concentration of the colloid in the water is responsible for the number and strength of the bonds and thus the modulus of elasticity.
  • This modulus represents or is synonymous with the gel strength already referred to in the introduction.
  • the modulus of elasticity or the gel strength is time-dependent, because the formation of the network from the colloids is time-dependent, as the following example makes clear:
  • Fig. 1 the time course of gel formation according to Fann for a 2.5 wt .-% aqueous bentonite solution with the brand name "tribomont" is shown.
  • the Y-axis represents the gel strength in divisions, where the respective Y-value multiplied by 0.48 indicates the gel strength in Pa.
  • the time in seconds is removed. Only when shear stresses or general mechanical forces act on the gel, the network described above breaks and then larger volumes of the gel can be shifted against each other, which then results in a (previously not observed, of course) certain viscosity of the gel.
  • the load on a gel caused by a particle is proportional to the quotient of the weight and the projection area of the particle. Since the volume of the respective particle (s) in an assumed spherical appearance increases with the cube of the radius, but the projection surface only increases with the square of the radius, a large particle (abrasive grain) in a given gel becomes more likely than sink a small sphere of equal density.
  • the gel point and the gel strength are determined.
  • the pendulum devices according to WEISS (DIN 4127) and the ball harp according to SOOS (DIN V 4126-100, Section 6.1.2 ff.) are available as test devices.
  • the ball harp according to SOOS consists of spheres of the same density with different radii, which are connected via threads of different lengths to a frame, which is lowered into the gel to be examined. One then determines which sphere radius no longer sinks into the gel. This spherical radius of known density allows a statement about the bearing capacity of the gel and consequently both the gel point and the gel strength.
  • the gel strength of a thixotropic suspension or of the water-based thixotropic dispersion medium according to the invention can be determined. It makes use of the fact that a gel can transmit shear forces. So if the viscous Simeter between two nested cylinders with a distance x a gel, so at the beginning of a slow rotational movement of the cylinder to another torque is transmitted, which can be measured.
  • the gel strength is given in the already indicated scale parts, the scale parts being converted into the gel strength with the unit Pa by multiplying the scale values by the factor 0.48, as already explained with reference to FIG.
  • the gel strength depends on the time in which the gel is not subjected to any shear stress.
  • Tribomont (bentonite) in one liter of deionized water at 3000 rpm per
  • Fig. 1 shown. Already after about 10 sec. Resting time showed the aqueous suspension or the thus prepared thixotropic and in
  • Substantially water-based dispersion medium has a shear modulus of about one Pa. So that a particle can sink in this gel, must therefore
  • the solid line generally shows the sedimentation behavior of particles in a liquid. It is on the Y-
  • X-axis be represented radius r.
  • abrasive grains having a particle size below 100 microns preferably having a diameter of less than 50 microns
  • These design rules apply in any case for the approach of the mixture in the course of its use in the subsequent wire cutting or wire sawing.
  • the dispersion medium is diluted with water as a rule until a sedimentation of the abrasive effect occurs Grains is effected, namely at a suitable gel strength of the resulting from the thus prepared dispersion medium gel (see Fig. 2).
  • the dilution is carried out until the desired abrasive particles to be sedimented actually sink through the stationary dispersion medium (gel) to the bottom of an associated container and deposit themselves here.
  • the process of preparing the mixture of the abrasive grains and the thixotropic and substantially water-based dispersion medium takes place only when a certain degree of contamination of the mixture is achieved here by additionally dissolved fine particles or fines (mostly abrasion). This degree of contamination can be determined optically, for example. If the mixture is soiled that it has to be treated, it is completely or partially removed from the actual chip-removing separation process. Only then is the dispersion medium diluted and dispersed, to such an extent that the abrasive grains (for the first time) sediment (can). Because in the previously completed separation process sedimentation should not take place so as not to clog the separator.
  • the sedimentation of the abrasive grains can be done by diluting the dispersion medium with water and / or by the fact that the mixture is no longer - as in the separation process - kept moving or reassured.
  • the sedimentation can also be achieved by introducing a shearing action.
  • the dispersion medium formed in this way will be approx. 1 min. Rest period without shear forces a gel strength of about 1 N / m 2 according to a Pa. Consequently, a particle sinking and sedimenting in this gel, ie the abrasive grain in the example, must produce a pressure of more than 1 Pa in order to be able to sediment in such a gel. If one starts from a spherical volume of the abrasive grain, the corresponding minimum grain diameter is calculated to be approximately 60 ⁇ m.
  • the thixotropic dispersion medium thus set retains abrasive grains in its quiescent state or does not sediment grains having a grain diameter of less than 60 ⁇ m.
  • abrasives or abrasive grains of other density such as boron nitride, corundum, diamond, etc., of course, other grain diameter, as the previously explained diagram corresponding to FIG. 2 makes clear.
  • Such a dispersion medium is diluted, that is, the proportion of the clay mineral in the example to the already mentioned about 1 wt .-% to 1, 5 wt .-% is reduced, so decreases accordingly, the viscosity and consequently the gel strength, so that now abrasive particles with particle diameters well below 60 microns can still sediment.
  • predominantly fines are retained in the dispersion medium, that is, grains in the mixture having a grain diameter of perhaps 20 ⁇ m or 10 ⁇ m and below.
  • These fines are generally flocculated according to the invention after separation of the suspension above the sediment. Most of these are unwanted fines from the cut material or silicon and abrasion of the grains or the silicon carbide or other abrasive.
  • These fines are flocculated by the already contained clay minerals and optionally with the addition of further clay minerals and optionally a flocculant.
  • the pH or the electrolyte concentration of the mixture can also be changed and the flocculation and consequently sedimentation can be achieved.
  • the silicon or pure silicon contained in the suspension or the dispersion medium can be separated as valuable material by other methods, for. B. discharged by flotation of the other solids become. The silicon thus obtained can be recycled back into the material cycle, for example reflowing and processing into polysilicon or, in the best case, monocrystalline silicon.
  • the grains of the abrasive or the abrasive grains are virtually impossible or hardly lost.
  • the flocculated material is harmless to health and can be used for secondary use. Disposal via a normal landfill is possible. This means that special disposal measures do not have to be taken.
  • the dispersion medium is composed of the dispersion medium (usually water) and an additive which regularly provides the desired thixotropy.
  • This additive usually the clay mineral
  • the abrasive grains of, for example, silicon carbide. The dry mix of the additive and the abrasive grains is then completed to the mixture just prior to processing with the dispersant.
  • transport costs are saved, because the dispersion medium (water) is usually already present at the place of chip removal machining.
  • the mixture of the dispersion medium and the abrasive grains is prepared, then the said mixture for chip removal machining, in particular for the chip-removing separation of workpieces and here preferably Haibieitermaterialien used.
  • the soiled mixture is wholly or partly treated as described.
  • the abrasive grains are separated from the (soiled) mixture. Comparative example
  • a mixture of polyethylene glycol and silicon carbide grains having an average grain diameter of 10 ⁇ m is used.
  • the silicon carbide grains are added in a ratio of 1 kg to 1 l of the polyethylene glycol. This results in a total density of the suspension of about 1, 6 kg / l.
  • the viscosity of this known dispersion is in the range of about 350 mPas.
  • the mixture of the present invention does not show such even after 60 hours.
  • This can essentially be attributed to the fact that the bentonite suspended in water, even at the adjusted concentration of 2% by weight with its colloid and charged smectite platelets, forms the previously mentioned network and contains therein the Silicon carbide grains (or other abrasive grains) are kept so that they can not sediment.
  • the mechanical interlocking of the pointed silicon grains with each other is reduced because they are spaced in the network. As a result, the mixture can be solved with little mechanical effort and transport easily.
  • the dynamic viscosity is in the range of about 40 mPas.
  • the piping of the separator can be easily cleaned by rinsing with water. Mechanical cleaning is not required.
  • the rinse water can be disposed of via the sewage system.
  • a mixture according to the invention of 1 kg of silicon carbide grains having a mean grain size in the range of about 10 ⁇ m with 1 l of the dispersion medium which contains 2.5% by weight of bentonite leads to a dynamic viscosity of 150 mPas.
  • all solids with a particle size smaller than 5 microns from the reusable solids content greater than 5 microns (abrasives) are separated in the example.
  • a clay mineral or generally phyllosilicate is used for producing the thixotropic properties of the dispersion medium.
  • clay minerals are due to their extremely large, especially inner surfaces of several 100 m 2 / g in a position to store in the mixture to be treated, in particular metal abrasion, store or store.
  • metal abrasion in particular iron abrasion
  • the iron particles are now absorbed by the clay mineral present in the dispersion medium and consequently can not adversely affect the cutting properties of the abrasive particles, as has hitherto been the case. This ensures that the abrasive particles practically without additional (acid) treatment after their sedimentation can be fed directly to a recycling or can be re-introduced into the circulation for a subsequent separation process.
  • the iron present in the polluted dispersion medium or the iron particles as such can not be adsorbed by the clay mineral in the dispersion medium. Rather, only the adsorption of iron cations takes place. For this reason, the metallic iron in the (polluted) thixotropic and substantially water-based dispersion medium according to the invention must be oxidized. This is generally ensured by oxygen or air injection using a compressed air line.
  • such iron particles or resulting water-insoluble compounds generally belong to the fine particles and are flocculated together with the other fine particles.
  • a further factor contributing to this is the fact that a sedimentation device for the treatment of the mixture is generally equipped with the already mentioned connected gas source, in particular an air source. With the help of this air source, the aufaufende mixture is applied to the interior and foamed. At the same time, the air introduced into the mixture to be treated ensures that any iron still present in the mixture undergoes oxidation and is brought into a filterable form by the possible addition of flocculants.
  • the gas or air introduced into the mixture to be treated ensures that premature sedimentation of the abrasive or abrasive grains is prevented. Because due to the described dilution of the dispersion medium in the course of treatment (dilution of the dispersion medium until the Bentonitanteii is about 1 wt .-% to 1, 5 wt .-%) this is regularly no longer able to abrasive grains of the grains Be able to carry particles.
  • the air supply produces a total mixing, but does not result in shear forces, Therefore, after the application of air, the desired gel forms relatively quickly and a good separation result is observed.
  • the tank for the mixture as well as any sedimentation device may also be equipped with a perforation release agent.
  • This perforation release agent is, according to an advantageous design, a microperforated floor or a microperforated partition wall.
  • the compressed air or generally a gas can be introduced under pressure.
  • the fine particles of clay mineral, silicon abrasion of the grains, etc. which collect above them, are first separated by suction or pouring off the abrasive grains.
  • the sediment from the abrasive grains is then overcoated with water or generally a liquid and again brought with the aid of compressed air from the microperforated base plate or the perforation release agent with the water layered over into a homogeneous suspension to this suspension from the sedimentation or a To pump appropriately designed container and, for example, in the circuit to transfer directly into the tank for the mixture through which the wire of the wire saw is guided or with the help of which the wire of the wire saw undergoes wetting by the mixture.
  • the proportion of water is thus about 97.6 wt .-% based on the
  • the sedimentation device 4 is provided with a microperforated intermediate wall or, in general, a perforation separator, in the present case a bottom 5. equipped, in which in the example, a pressure line 6 is connected. In this way, compressed air can be injected into the microperforated floor or the intermediate wall 5.
  • this suspension of water and abrasives can be thickened by a FesWlüssig separation.
  • processes are preferably used again in which the abrasive grains are separated from the liquid phase by gravity, since this prevents clogging of sieves.
  • a lamellar thickener which has a high separation efficiency with little space and without moving parts.
  • Iron content is determined by determining the weight loss of the lapped
  • Sediment is separated by decantation. Subsequently, both the fine fraction and the sediment are dried at about 105 ° C to determine the solids content. As a reference, a sample of the unpurified original and unpolluted mixture is also dried.
  • All samples are digested with nitric acid to have all the iron present as trivalent ions.
  • the analysis of the iron content is done by atomic absorption spectroscopy.
  • the amount of iron in the separated fines of the treated mixture is thus about 100 times greater than the iron content in the sedimented recycled silicon carbide, which is virtually free of iron.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Processing Of Stones Or Stones Resemblance Materials (AREA)
  • Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
  • Mechanical Treatment Of Semiconductor (AREA)
  • Grinding-Machine Dressing And Accessory Apparatuses (AREA)

Abstract

L'invention concerne un procédé et un dispositif pour traiter un mélange servant d'abrasif constitué d'un milieu de dispersion thixotrope et de grains abrasifs. Ce mélange est utilisé pour l'usinage par enlèvement de copeaux, notamment pour la séparation par enlèvement de copeaux, de pièces, de préférence de cristaux de semi-conducteurs. Selon l'invention, on utilise un milieu de dispersion thixotrope et sensiblement aqueux.
PCT/EP2008/008827 2007-10-19 2008-10-17 Procédé et dispositif pour traiter un mélange servant d'abrasif constitué d'un milieu de dispersion thixotrope et de grains abrasifs WO2009053007A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102007050483.9 2007-10-19
DE102007050483A DE102007050483A1 (de) 2007-10-19 2007-10-19 Mischung aus einem thixotropen Dispersionsmedium sowie abrasiv wirkenden Körnern als Schleifmittel

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Publication Number Publication Date
WO2009053007A1 true WO2009053007A1 (fr) 2009-04-30

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Family Applications (4)

Application Number Title Priority Date Filing Date
PCT/EP2008/008826 WO2009053006A1 (fr) 2007-10-19 2008-10-17 Utilisation d'un mélange constitué principalement d'un milieu de dispersion thixotrope et de grains abrasifs comme abrasif
PCT/EP2008/008827 WO2009053007A1 (fr) 2007-10-19 2008-10-17 Procédé et dispositif pour traiter un mélange servant d'abrasif constitué d'un milieu de dispersion thixotrope et de grains abrasifs
PCT/EP2008/008819 WO2009053003A1 (fr) 2007-10-19 2008-10-17 Procédés de séparation de solides
PCT/EP2008/008820 WO2009053004A1 (fr) 2007-10-19 2008-10-17 Scies hélicoïdales comportant des suspensions de rodage thixotropes

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PCT/EP2008/008826 WO2009053006A1 (fr) 2007-10-19 2008-10-17 Utilisation d'un mélange constitué principalement d'un milieu de dispersion thixotrope et de grains abrasifs comme abrasif

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PCT/EP2008/008819 WO2009053003A1 (fr) 2007-10-19 2008-10-17 Procédés de séparation de solides
PCT/EP2008/008820 WO2009053004A1 (fr) 2007-10-19 2008-10-17 Scies hélicoïdales comportant des suspensions de rodage thixotropes

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DE (1) DE102007050483A1 (fr)
WO (4) WO2009053006A1 (fr)

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JP5515593B2 (ja) * 2009-10-07 2014-06-11 株式会社Ｓｕｍｃｏ ワイヤーソーによるシリコンインゴットの切断方法およびワイヤーソー
CN102229792B (zh) * 2010-09-16 2013-10-09 蒙特集团（香港）有限公司 一种太阳能硅片切割砂浆
DE102011018359A1 (de) 2011-04-20 2012-10-25 Schott Solar Ag Verfahren zum Drahtsägen im Pendelmodus
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CN112452528B (zh) * 2020-11-05 2022-04-22 苏州易奥秘光电科技有限公司 一种磁性纳米粒子一致性筛选方法
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