WO2012144161A1 - Procédé de production de fil de noyau de silicium - Google Patents

Procédé de production de fil de noyau de silicium Download PDF

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Publication number
WO2012144161A1
WO2012144161A1 PCT/JP2012/002505 JP2012002505W WO2012144161A1 WO 2012144161 A1 WO2012144161 A1 WO 2012144161A1 JP 2012002505 W JP2012002505 W JP 2012002505W WO 2012144161 A1 WO2012144161 A1 WO 2012144161A1
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WO
WIPO (PCT)
Prior art keywords
core wire
silicon
mass
hydrofluoric acid
silicon core
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PCT/JP2012/002505
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English (en)
Japanese (ja)
Inventor
靖志 黒澤
祢津　茂義
哲郎 岡田
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信越化学工業株式会社
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Publication of WO2012144161A1 publication Critical patent/WO2012144161A1/fr

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    • 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
    • C01B33/037—Purification

Definitions

  • the present invention relates to a method of producing a silicon core wire used for producing a polycrystalline silicon rod.
  • the Siemens method is known as a manufacturing method of the polycrystalline silicon used as the raw material of the single crystal silicon for semiconductors, or the silicon
  • the Siemens method is a method of vapor phase growing polycrystalline silicon on the surface of a silicon core wire by using a CVD (Chemical Vapor Deposition) method by bringing a source gas containing chlorosilane into contact with a heated silicon core wire.
  • CVD Chemical Vapor Deposition
  • the reactor for vapor phase growth of polycrystalline silicon by the Siemens method is composed of an upper structure called bell jar and a lower structure (bottom plate) called base plate, and two silicon core wires in the vertical direction in this space,
  • the torii type is assembled in a horizontal direction, and both ends of the torii type silicon core wire are fixed to a pair of metal electrodes disposed on the base plate via a pair of carbon core wire holders.
  • the electrode passes through the base plate with an insulator interposed, and is connected to another electrode through a wire or is connected to a power source disposed outside the reactor.
  • the electrode, the base plate and the bell jar are cooled using a coolant such as water in order to prevent the deposition of polycrystalline silicon during vapor phase growth.
  • a mixed gas of, for example, trichlorosilane and hydrogen as a source gas is supplied from the gas nozzle into the reaction furnace while conducting current from the electrode and heating the silicon core wire to a temperature range of 900 ° C. to 1200 ° C. in a hydrogen atmosphere,
  • the silicon is vapor-phase grown on the core line, and a polycrystalline silicon rod of a desired diameter is formed in an inverted U shape.
  • the silicon core wire used for producing high purity polycrystalline silicon needs to be a high purity one having a low impurity concentration. is there. Specifically, the material is required to have a high resistance of about 500 ⁇ cm or more.
  • a carbon heater for initial heating is provided at the center or inner peripheral surface of the reactor for the above-mentioned initial heating, and this carbon heater is first Heat is generated by energization, and the silicon core wire disposed around the carbon heater is heated to a desired temperature by radiant heat generated at that time.
  • a voltage of 2.0 V / cm to 8.0 V / cm per length Is required.
  • a voltage of 1600 V to 6400 V is required.
  • the surface temperature is maintained by the heat generation of the silicon core wire itself thereafter without using heating using a carbon heater, so the precipitation reaction proceeds continuously. Therefore, the power supply of the carbon heater is turned off after the above-mentioned energization start to the silicon
  • spark discharge is particularly likely to occur between the silicon core wire and the core wire holder made of carbon.
  • the spark discharge between the silicon core wire and the core wire holder damages the silicon core wire and causes flaws. Such a flaw causes the collapse of the silicon core wire during the polycrystalline silicon deposition reaction, and causes the reduction of the productivity of polycrystalline silicon.
  • the present invention has been made to solve such problems, and aims to suppress the occurrence of spark discharge between a silicon core wire and another conductive member, and to improve the productivity of polycrystalline silicon. Do.
  • the manufacturing method of the silicon core wire concerning the present invention is a manufacturing method of the silicon core wire for polycrystalline silicon stick manufacture, and the mixed acid of hydrofluoric acid and nitric acid is used for the silicon core wire cut out from the silicon ingot. And etching the surface of the silicon core wire with a solution of hydrofluoric acid.
  • the hydrofluoric acid concentration of the hydrofluoric acid solution is 1% by mass or more and 20% by mass or less, and more preferably 3% by mass or more and 10% by mass or less.
  • the mixed acid solution has a hydrofluoric acid concentration of 1% by mass to 50% by mass, and a nitric acid concentration of 1% by mass to 70% by mass, and more preferably, a hydrofluoric acid concentration of 5% by mass to 10%.
  • Mass% or less and nitric acid concentration are 40 mass% or more and 63 mass% or less.
  • the method for producing a silicon core wire according to the present invention includes the step of removing the oxide film on the surface generated during the production of the silicon core wire, so that spark discharge can be prevented when a high voltage is applied.
  • FIG. 1 is a schematic cross-sectional view showing an example of the configuration of a reaction furnace 100 for producing polycrystalline silicon.
  • the reaction furnace 100 is an apparatus for vapor phase growing polycrystalline silicon on the surface of a silicon core wire 11 by the Siemens method to obtain a polycrystalline silicon rod 12, and is constituted by a base plate 5 and a bell jar 1.
  • the base plate 5 is provided with a metal electrode 10 for supplying a current to the silicon core wire 11, a gas nozzle 9 for supplying a process gas such as nitrogen gas, hydrogen gas or trichlorosilane gas, and an exhaust port 8 for discharging exhaust gas. . Further, the base plate 5 has an inlet portion 6 and an outlet portion 7 of a refrigerant for cooling itself.
  • the bell jar 1 has an inlet 3 and an outlet 4 for cooling the refrigerant itself, and further has a viewing window 2 for visually confirming the inside from the outside.
  • FIG. 2 is a view for explaining an example of the arrangement of the electrodes 10, the adapter 14, the core holder 13, and the silicon core 11.
  • the metal electrode 10 has a refrigerant inlet 15 and an outlet 16 for cooling itself, and has a structure on which an adapter 14 can be mounted.
  • the core holder 13 is fixed to the upper portion of the adapter 14, and the silicon core 11 is fixed to the core holder 13.
  • the adapter 14 and the core holder 13 do not need to be provided as separate members, and may be an integral core holder in which the adapter 14 and the core holder 13 are a single member.
  • the electrode 10, the adapter 14, the core holder 13, and the silicon core 11 are required to have a contact area necessary for energization. In addition, it is necessary to have sufficient strength to hold a polycrystalline silicon rod obtained by a precipitation reaction of polycrystalline silicon.
  • FIG. 3 is a view for explaining the arrangement of the core holder 13 and the silicon core 11. The current flowing through the silicon core wire 11 flows in the direction of the arrow shown by the broken line.
  • the spark discharge generated between the core wire holder 13 and the silicon core wire 11 is formed on the surface of the silicon core wire 11 and the contact resistance between the core wire holder 13 and the silicon core wire 11 Oxide film is found to be the main cause.
  • the contact resistance can be lowered by improving the fixing method of the silicon core wire 11 or the like. It was also found that the thickness of the oxide film on the surface of the silicon core wire differs depending on the method of manufacturing the silicon core wire, and spark discharge is easily caused when the oxide film which is an insulating film is thick.
  • An oxide film formed on the surface of a silicon crystal is known as a so-called natural oxide film, and its thickness is generally considered to be 0.2 nm to 0.8 nm (see, for example, Non-Patent Document 1) . It is assumed that an oxide film of this thickness does not have a large electrical resistance to cause spark discharge. However, according to experiments conducted by the present inventors, the oxide film on the surface of the silicon core wire may reach 50 nm, which is caused by etching for removing the working strain generated at the time of cutting out the silicon core wire. It turned out that it was in the process.
  • FIG. 4 and FIG. 5 are respectively the manufacturing process flow diagrams of the present invention and the conventional silicon core wire.
  • the silicon core wire is cut out from a cylindrical ingot of single crystal silicon or polycrystalline silicon (S101), and the removal margin is usually 50 ⁇ m to 200 ⁇ m for the purpose of removing the residual strain generated at the time of cutting.
  • An etching process using a mixed acid solution of hydrofluoric acid and nitric acid to an extent is performed (S102), and after the etching, it is used for a precipitation reaction of polycrystalline silicon (S103).
  • S102 a mixed acid solution of hydrofluoric acid and nitric acid to an extent
  • S103 polycrystalline silicon
  • a thick oxide film is formed on the surface of the silicon core wire in the etching process, which causes spark discharge.
  • the surface of the silicon core wire is cleaned with a hydrofluoric acid solution to remove the surface oxide film.
  • a step (S104) is provided.
  • the hydrofluoric acid concentration of the hydrofluoric acid solution at this time is preferably 1% by mass to 20% by mass, and more preferably 3% by mass to 10% by mass.
  • the temperature of this hydrofluoric acid treatment is preferably 0 to 40 ° C., more preferably 10 to 30 ° C.
  • the hydrofluoric acid treatment time depends on the concentration of hydrofluoric acid and the temperature of the hydrofluoric acid solution, but as a standard, it is preferably 10 to 50 minutes, more preferably 15 to 20 minutes. For example, when the immersion treatment is performed at a hydrofluoric acid solution temperature of 25 ° C. for 15 minutes, the oxide film can be removed by about 50 nm.
  • the mixed acid solution of hydrofluoric acid and nitric acid used in the etching step (S102) preferably has a hydrofluoric acid concentration of 1% by mass to 50% by mass and a nitric acid concentration of 1% by mass to 70% by mass, more preferably Is a hydrofluoric acid concentration of 5% by mass to 10% by mass, and a nitric acid concentration of 40% by mass to 63% by mass.
  • the temperature of the etching solution is controlled to 0 to 50 ° C., preferably 10 to 40 ° C.
  • etching is performed using a mixed acid solution of 5 mass% hydrofluoric acid and 63 mass% nitric acid as an etching solution.
  • the time required to etch away the 200 ⁇ m working strain layer is about 20 minutes, at which time the in-tank etchant temperature rises from 22 ° C to 28 ° C.
  • Example 1 The difference in the thickness of the surface oxide film was confirmed depending on the presence or absence of the hydrofluoric acid treatment after etching with the mixed acid solution of hydrofluoric acid and nitric acid.
  • the mixed acid solution of hydrofluoric acid and nitric acid is 5 mass% of hydrofluoric acid / 63 mass% of nitric acid for Example 1 and Comparative Example 1, and 8 mass% of hydrofluoric acid / 50 mass% of nitric acid for Comparative Example 2.
  • the width of each is 150 ⁇ m.
  • a silicon wafer with a diameter of 8 inches was used as a sample.
  • the oxide film thickness was measured at 4 points (P1 to 4) for each sample. The results are summarized in Table 1. As apparent from the results, when the hydrofluoric acid treatment is not performed, a significantly thick oxide film is present.
  • Example 2 The silicon core wire was actually set in the reaction furnace and only the initial energization was performed, and the presence or absence of the surface flaw was visually confirmed.
  • the silicon core wire is an 8 mm square of polycrystal core and its length is 1500 mm.
  • a mixed acid solution of hydrofluoric acid and nitric acid is 5 mass% of hydrofluoric acid / 63 mass% of nitric acid, and the removal is 150 ⁇ m.
  • Table 2 the precipitation reaction was conducted for experiments of only one batch using eight silicon cores. As is clear from the results, while flaws occurred in 6 out of 8 when the hydrofluoric acid treatment was not performed, occurrence of flaws was observed in all silicon core wires when the hydrofluoric acid treatment was performed. It was not.
  • Example 3 The precipitation reaction of polycrystalline silicon was actually performed, and the yield was compared in the sequence of growing polycrystalline silicon to 120 mm ⁇ .
  • the silicon core wire is an 8 mm square of polycrystal core and its length is 1500 mm.
  • a mixed acid solution of hydrofluoric acid and nitric acid is 5 mass% of hydrofluoric acid / 63 mass% of nitric acid, and the removal is 150 ⁇ m.
  • Table 3 In each of Example 3 and Comparative Example 4, five batches of experiments were conducted using eight silicon cores per batch.
  • the present invention it is possible to prevent problems such as the collapse of the silicon core wire at the initial stage of the reaction in the Siemens method, and to improve the operation rate of the polycrystalline silicon manufacturing apparatus.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Silicon Compounds (AREA)

Abstract

L'invention concerne un procédé qui comporte les étapes consistant à: découper (S101) un fil de noyau de silicium à partir d'un lingot cylindrique de silicium monocristallin ou de silicium polycristallin; afin de supprimer un gauchissement résiduel produit pendant le traitement de découpage, mettre en oeuvre un traitement de gravure (S102) utilisant une solution mixte d'acides comprenant de l'acide fluorhydrique et de l'acide nitrique, de sorte que la quantité de matière éliminée soit normalement de l'odre de 50-200 μm; et utiliser (S103) le fil de noyau dans une réaction de précipitation du silicium polycrystallin consécutive à la gravure. A l'étape de traitement de gravure, un film d'oxyde épais est formé sur la surface du fil de noyau de silicium, le film étant un facteur déclenchant une décharge d'étincelles. Dans cette invention, une étape (S104) prévue permet d'éliminer le film d'oxyde de surface par un nettoyage de la surface du fil de noyau de silicium à l'aide d'une solution d'acide fluorhydrique, après l'étape visant à supprimer un gauchissement de traitement de la surface par la gravure du fil de noyau de silicium au moyen d'une solution mixte d'acides, qui comprend de l'acide fluorhydrique et de l'acide nitrique.
PCT/JP2012/002505 2011-04-19 2012-04-11 Procédé de production de fil de noyau de silicium WO2012144161A1 (fr)

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JP2011-092851 2011-04-19
JP2011092851A JP2012224499A (ja) 2011-04-19 2011-04-19 シリコン芯線の製造方法

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114555524A (zh) * 2019-11-05 2022-05-27 株式会社德山 硅芯线的蚀刻装置及硅芯线的蚀刻方法
US11998955B2 (en) 2019-11-05 2024-06-04 Tokuyama Corporation Etching device for silicon core wire and etching method for silicon core wire

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013018675A (ja) * 2011-07-11 2013-01-31 Shin-Etsu Chemical Co Ltd 多結晶シリコン製造装置
JP5820917B2 (ja) * 2014-10-03 2015-11-24 信越化学工業株式会社 多結晶シリコンの製造方法
WO2021090565A1 (fr) * 2019-11-05 2021-05-14 株式会社トクヤマ Dispositif de gravure pour fil à cœur de silicium et procédé de gravure pour fil à cœur de silicium

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0848512A (ja) * 1994-08-10 1996-02-20 Tokuyama Corp 多結晶シリコン粒子
JPH0867511A (ja) * 1994-08-31 1996-03-12 Tokuyama Corp 多結晶シリコンの製造方法
JPH11168076A (ja) * 1997-09-19 1999-06-22 Wacker Chemie Gmbh 多結晶シリコン
JP2004149324A (ja) * 2002-10-28 2004-05-27 Sumitomo Mitsubishi Silicon Corp 多結晶シリコンロッド及びその製造方法、並びにそのロッドの製造に使用されるシリコン芯材
JP2005112662A (ja) * 2003-10-07 2005-04-28 Sumitomo Titanium Corp 多結晶シリコンロッド及びその製造方法
JP2009173531A (ja) * 2007-12-28 2009-08-06 Mitsubishi Materials Corp 多結晶シリコンのシリコン芯棒組立体及びその製造方法、多結晶シリコン製造装置、多結晶シリコン製造方法
JP2010235440A (ja) * 2009-03-10 2010-10-21 Mitsubishi Materials Corp 多結晶シリコン製造装置
JP2011063471A (ja) * 2009-09-16 2011-03-31 Shin-Etsu Chemical Co Ltd 多結晶シリコン塊および多結晶シリコン塊の製造方法

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0848512A (ja) * 1994-08-10 1996-02-20 Tokuyama Corp 多結晶シリコン粒子
JPH0867511A (ja) * 1994-08-31 1996-03-12 Tokuyama Corp 多結晶シリコンの製造方法
JPH11168076A (ja) * 1997-09-19 1999-06-22 Wacker Chemie Gmbh 多結晶シリコン
JP2004149324A (ja) * 2002-10-28 2004-05-27 Sumitomo Mitsubishi Silicon Corp 多結晶シリコンロッド及びその製造方法、並びにそのロッドの製造に使用されるシリコン芯材
JP2005112662A (ja) * 2003-10-07 2005-04-28 Sumitomo Titanium Corp 多結晶シリコンロッド及びその製造方法
JP2009173531A (ja) * 2007-12-28 2009-08-06 Mitsubishi Materials Corp 多結晶シリコンのシリコン芯棒組立体及びその製造方法、多結晶シリコン製造装置、多結晶シリコン製造方法
JP2010235440A (ja) * 2009-03-10 2010-10-21 Mitsubishi Materials Corp 多結晶シリコン製造装置
JP2011063471A (ja) * 2009-09-16 2011-03-31 Shin-Etsu Chemical Co Ltd 多結晶シリコン塊および多結晶シリコン塊の製造方法

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114555524A (zh) * 2019-11-05 2022-05-27 株式会社德山 硅芯线的蚀刻装置及硅芯线的蚀刻方法
US11998955B2 (en) 2019-11-05 2024-06-04 Tokuyama Corporation Etching device for silicon core wire and etching method for silicon core wire

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