Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B33/00—Silicon; Compounds thereof
  • C01B33/02—Silicon
  • C01B33/021—Preparation
  • C01B33/027—Preparation by decomposition or reduction of gaseous or vaporised silicon compounds other than silica or silica-containing material
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B33/00—Silicon; Compounds thereof
  • C01B33/02—Silicon
  • C01B33/021—Preparation
  • C01B33/027—Preparation by decomposition or reduction of gaseous or vaporised silicon compounds other than silica or silica-containing material
  • C01B33/03—Preparation by decomposition or reduction of gaseous or vaporised silicon compounds other than silica or silica-containing material by decomposition of silicon halides or halosilanes or reduction thereof with hydrogen as the only reducing agent
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
  • B01D71/06—Organic material
  • B01D71/30—Polyalkenyl halides
  • B01D71/32—Polyalkenyl halides containing fluorine atoms
  • B01D71/36—Polytetrafluoroethene
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B33/00—Silicon; Compounds thereof
  • C01B33/02—Silicon
  • C01B33/021—Preparation
  • C01B33/027—Preparation by decomposition or reduction of gaseous or vaporised silicon compounds other than silica or silica-containing material
  • C01B33/035—Preparation by decomposition or reduction of gaseous or vaporised silicon compounds other than silica or silica-containing material by decomposition or reduction of gaseous or vaporised silicon compounds in the presence of heated filaments of silicon, carbon or a refractory metal, e.g. tantalum or tungsten, or in the presence of heated silicon rods on which the formed silicon is deposited, a silicon rod being obtained, e.g. Siemens process
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
  • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
  • C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
  • C23C16/442—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating using fluidised bed process
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
  • F24F3/00—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems
  • F24F3/12—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling
  • F24F3/16—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by purification, e.g. by filtering; by sterilisation; by ozonisation
  • F24F3/167—Clean rooms, i.e. enclosed spaces in which a uniform flow of filtered air is distributed

Definitions

• the invention relates to a process for the production of polycrystalline silicon.
• Polycrystalline silicon often also called polysilicon for short, is usually produced by means of the Siemens process.
• Siemens reactor bell-shaped reactor
• the filament rods are usually placed vertically in electrodes located at the bottom of the reactor, via which the connection to the power supply takes place.
• Two filament rods each are coupled via a horizontal bridge (also made of silicon) and form a carrier body for silicon deposition.
• the bridging coupling produces the typical U-shape of the support bodies, which are also called thin rods.
• High-purity polysilicon deposits on the heated rods and the bridge, causing the rod diameter to increase over time (CVD /
• these polysilicon rods are usually further processed by mechanical processing into fragments of different size classes, classified, optionally subjected to a wet-chemical cleaning and finally packaged.
• An alternative to the Siemens process are fluidized bed processes in which polycrystalline silicon granules are produced. This is done by fluidization of silicon particles by means of a gas flow in a fluidized bed, which is heated by a heater to high temperatures. By adding a silicon-containing reaction gas, a pyrolysis reaction takes place on the hot Particle surface. Here, elemental silicon is deposited on the silicon particles and the individual particles grow in diameter. By the regular withdrawal of grown particles and addition of smaller silicon particles as seed particles, the process can be operated continuously with all the associated advantages.
• silicon-containing educt gas silicon-halogen compounds (eg, chlorosilanes or bromosilanes), monosilane (SiH), and mixtures of these gases with hydrogen are described.
• US 2013/0189176 A1 discloses a polycrystalline silicon piece with a
• the dopant surface contaminants of polycrystalline silicon can be determined by examining two rods of polycrystalline silicon rods produced by deposition in a Siemens reactor, one immediately after deposition for impurities with dopants (bulk and surface), while the second rod examines the equipment in which the rod is further processed, passes through and, after passing through the equipment, is also examined for impurities with dopants (bulk and surface). Since both bars can be assigned the same level of bulk impurities, the difference between the two impurities determined results in the surface contamination caused by the further processing steps such as comminution, cleaning, transporting and packaging. This can at least be ensured if rod and brother rod deposited on one and the same U-shaped support body were. This method, which is referred to below, is described in US 2013/0186325 A1.
• Dopants (B, P, As, Al) are analyzed by photoluminescence in the context of US 2013/0189176 A1 according to SEMI MF 1398 on an FZ single crystal (SEMI MF 1723) produced from the polycrystalline material.
• a disk (wafer) is separated from the monocrystalline rod produced from a polycrystalline silicon rod or polycrystalline silicon fragments by means of FZ, etched with HF / HNO 3 , rinsed with 18 MOH of water and dried. At this disc are the
• the facilities are located in a clean room of class 100 or better (according to US FED STD 209E, superseded by ISO 14644-1).
• class 100 ISO 5
• a wet-chemical treatment of the fragments in a cleaning system is optionally carried out.
• the cleaning system is located in a clean room of class less than or equal to 10000, preferably in a clean room of class 100 or better. Again, only clean room filters are used with a PTFE membrane, with a structure and a composition as described above.
• DE 10 201 1 004 916 A1 discloses a process for drying polysilicon, wherein an air stream is passed through a filter at a flow rate of 0.1 to 3 m / s and a temperature of 20 to 100 ° C, then passes through a perforated air distribution plate and then directed to a process dish containing polysilicon to dry it.
• Air filters currently used in clean rooms include Ultra Low Penetration Air (ULPA) and High Efficiency Particle Air (HEPA) filters.
• ULPA Ultra Low Penetration Air
• HEPA High Efficiency Particle Air
• the filter mats used are usually mounted in plywood or metal frames for easy replacement.
• the filter medium itself consists, as with most air filters, of glass fiber mats which have a fiber diameter of about 1-10 m.
• EP 1 291 063 A1 discloses a clean room comprising an air filter, wherein a gap between a filter medium and a frame is sealed by a sealing material, the entire filter medium and the sealing material being formed of a material containing gaseous organic phosphorus compounds in an amount of 10 g or less per 1 g of the material as measured by a Purge & Trap method, and leaching boron compounds in an amount of 20 g or less per 1 g of the material after immersion in ultrapure water for 28 days.
• the air filter is manufactured by treating glass fibers or organic fibers such as those of polytetrafluoroethylene with a treating agent such as a binder made of an acrylic resin or the like, a non-silicon type water repellent, a plasticizer and a
• predetermined size is set and a portion between the frame and the filtration medium is tightly sealed with a sealing material, wherein
• Treatment center and as sealing material, those are selected and used which, during use of the clean room, do not contain gaseous organic compounds
• the air was taken directly from the Fresh air sucked in via fans and passed over low-dumb particle filters of class U 17 (according to EN 1822-1: 2009) with a PTFE membrane.
• Table 1 shows the surface contaminations determined in the process.
• polycrystalline silicon should have the following maximum surface contamination: B ⁇ 50 ppta; P ⁇ 50 ppta; As ⁇ 5 ppta; AI ⁇ 5 ppta.
• the object of the invention is achieved by a process for producing polycrystalline silicon comprising depositing polycrystalline silicon on a support body to obtain a polycrystalline silicon rod, or depositing polycrystalline silicon on silicon particles to obtain polycrystalline silicon granules, wherein the deposition each carried out in a reactor, which is located in a clean room of class 1 to 100000, with filtered air is fed into the clean room, wherein for filtering the air first at least one filter, the particles larger or gleichl pm deposits and then a
• HEPA filter which precipitates particles smaller than 1 pm, passes.
• the deposition of polycrystalline silicon on a carrier body is usually carried out by reacting gas containing a silicon-containing component and hydrogen in a reactor containing at least one heated carrier body on which polycrystalline silicon is deposited, whereby at least one polycrystalline silicon rod is obtained.
• the silicon rod is subsequently comminuted into polycrystalline silicon fragments.
• the preparation of the polycrystalline silicon granules is usually carried out in a fluidized bed reactor by fluidization of silicon particles by means of a
• the silicon-containing component is preferably a chlorosilane, more preferably trichlorosilane.
• the filter that separates particles larger than or equal to pm is preferably a fine dust filter for particles of size 1 -10 pm, ie a filter of classes M5, M6, F7-F9 according to EN 779.
• the air first passes through a coarse dust filter which separates particles> 10 pm, ie a filter of the classes G1-G4 according to EN 779.
• the prefiltration comprises a coarse dust filter and a fine dust filter.
• the particulate filter is preferably a particulate filter with PTFE membrane of the classes E10-E12, H13-H14, U15-U18 according to DIN EN 1822. Preference is given to a particulate matter filter with PTFE membrane of class U15 (class 100).
• airborne molecular contamination (AMC) filters e.g. from activated carbon filters or anion filters, to separate any gaseous boron and phosphorus compounds in the air.
• AMC filters e.g. from activated carbon filters or anion filters, to separate any gaseous boron and phosphorus compounds in the air.
• the AMC filter is the
• the AMC filter is preferably introduced between coarse dust filter and particulate filter.
• the pre-filtration uses filters made of synthetic, low-dopant materials. These are preferably mats with a PTFE membrane, with polyester fibers or with a Polypropylene fabric containing less than 0.1 wt.% Boron and phosphorus and less than 0.01 wt.% Arsenic, aluminum, sulfur and ⁇ 0.1 wt.% Sn. All adhesives and frames in which the filter mats are incorporated should also contain ⁇ 0.1% by weight of boron and phosphorus and less than 0.01% by weight of arsenic, aluminum and ⁇ 0.1% by weight of tin.
• the invention provides several filter stages for the separation of particles
• the particulate filters should achieve a separation efficiency of more than 99% for particles smaller than 0.2 pm. It has been shown that this can be accomplished by a two-stage prefiltration.
• the pre-filter stage 1 provides a coarse dust filter of class G1 to G 4 for particles> 10 pm.
• This consists of a synthetic material, preferably polypropylene or polyester.
• the pre-filter stage 2 provides a particulate matter filter class M5 or M6 or F7 to F9 for particles 1 to 10 ⁇ ago.
• This also consists of a synthetic material, preferably polypropylene or polyester.
• the final filter stage 3 provides a particulate filter class E10 to U17 for particles ⁇ 1 pm.
• the particulate filter consists of a synthetic material, preferably polypropylene or polyester.
• a two-stage system consisting of a particulate matter filter class M5 or M6 or F7 to F9 for particles 1 to 10 pm and one
• both the deposition of the polycrystalline silicon rods and the comminution of the silicon rods into fragments preferably take place in a class 1 to 100,000 clean room. For deposition, this means that all reactors in which polycrystalline silicon is deposited are in a clean room. This applies both to the deposition according to the Siemens process and to the deposition by means of a fluidized bed process in order to produce granules. This has the advantage that even when removing from the reactor, the silicon rods or granules from the beginning to see a clean low-particle air.
• the crushing plant is in a class 1 to 100,000 clean room.
• the polycrystalline silicon fragments or the polycrystalline silicon granules are optionally classified (e.g., by fractional sizes). It is preferred that the classifying equipment be in a class 1 to 100,000 clean room.
• the polycrystalline silicon fragments may be wet-chemical
• the cleaning plants and dryers are in a clean room of class 1 to 100,000, more preferably in a clean room of class 1 to 100.
• the polycrystalline silicon fragments are usually packed in plastic bags. It is preferred that the packaging installation is located in a clean room of class 1 to 00 000, more preferably in a clean room of class 1 to 100. If the polycrystalline silicon fragments were previously wet-chemically treated and dried, it is preferred if the entire transport path from the cleaning system / dryer to the packaging system is in a clean room of class 1 to 100,000, more preferably in a clean room of class 1 to 100.
• class 1 fiberglass filters of grade G4 and stage 2 class M6 fine particulate glass filters with> 10% by weight boron content there are class 1 fiberglass filters of grade G4 and stage 2 class M6 fine particulate glass filters with> 10% by weight boron content.
• Table 3 shows the surface contaminations determined with B, P, Al, As and C and the total sum of the dopants (B, P, Al, As) directly after installation of the filters (0 w), after 4 weeks (4 w), after 8 weeks (8 weeks), after 12 weeks (12 weeks), after 16 weeks (16 weeks) and after 20 weeks (20 weeks).
• Fig. 1 shows the time course of the contamination with boron.
• class G4 coarse dust filters are made of synthetic polypropylene and in the second stage class M6 particulate matter filters are made of synthetic polyester material.
• the filter mats of the coarse dust filter and the fine dust filter contain less than 0.1% by weight of boron and phosphorus and less than 0.01% by weight of arsenic, aluminum. In the clean room brother rods were laid out.
• the filter mats contain less than 0.1% by weight of boron and phosphorus and less than 0.01% by weight of arsenic, 0.01% by weight of aluminum and 0.2% by weight of tin. In the clean room brother rods were laid out.
• the fragment is sprayed with HF / HNO 3 .
• the acid is collected in a cup. Then the acid is evaporated and the residue is added to water.
• the metal content of the aqueous solution is measured by ICP-AES (Inductively Coupled Ion Plasma Atomic Emission Spectroscopy). From the measured values, the metal content of the poly surface is calculated.
• the filter mats contain less than 0.1% by weight of boron and phosphorus and less than 0.01% by weight of arsenic, 0.01% by weight of aluminum and 0.02% by weight of tin.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Inorganic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Mechanical Engineering (AREA)
• General Chemical & Material Sciences (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• General Engineering & Computer Science (AREA)
• Combustion & Propulsion (AREA)
• Silicon Compounds (AREA)
• Filtering Materials (AREA)
• Filtering Of Dispersed Particles In Gases (AREA)
• Separation Using Semi-Permeable Membranes (AREA)

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• 2013
  • 2013-10-28 DE DE201310221826 patent/DE102013221826A1/de not_active Withdrawn
• 2014
  • 2014-10-17 MY MYPI2016000581A patent/MY176742A/en unknown
  • 2014-10-17 US US15/032,227 patent/US9771651B2/en not_active Expired - Fee Related
  • 2014-10-17 EP EP14786183.5A patent/EP3063092A1/de not_active Withdrawn
  • 2014-10-17 JP JP2016526916A patent/JP6301465B2/ja not_active Expired - Fee Related
  • 2014-10-17 CN CN201480059376.8A patent/CN105829246B/zh not_active Expired - Fee Related
  • 2014-10-17 KR KR1020167010514A patent/KR101844911B1/ko active IP Right Grant
  • 2014-10-17 WO PCT/EP2014/072328 patent/WO2015062880A1/de active Application Filing
  • 2014-10-23 TW TW103136564A patent/TWI531693B/zh not_active IP Right Cessation

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