WO2018051472A1 - Method for removing chlorine trifluoride cleaning residues in sic epitaxial growth furnace system - Google Patents

Method for removing chlorine trifluoride cleaning residues in sic epitaxial growth furnace system Download PDF

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WO2018051472A1
WO2018051472A1 PCT/JP2016/077330 JP2016077330W WO2018051472A1 WO 2018051472 A1 WO2018051472 A1 WO 2018051472A1 JP 2016077330 W JP2016077330 W JP 2016077330W WO 2018051472 A1 WO2018051472 A1 WO 2018051472A1
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gas
epitaxial growth
growth furnace
chlorine trifluoride
cleaning
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PCT/JP2016/077330
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French (fr)
Japanese (ja)
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真鍋　俊樹
良英 小野
正 荘所
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岩谷産業株式会社
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Priority to SG11201901641UA priority Critical patent/SG11201901641UA/en
Priority to PCT/JP2016/077330 priority patent/WO2018051472A1/en
Priority to JP2018539461A priority patent/JP6796652B2/en
Publication of WO2018051472A1 publication Critical patent/WO2018051472A1/en

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    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/10—Inorganic compounds or compositions
    • C30B29/36—Carbides
    • 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
    • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
    • C23C16/42—Silicides
    • 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
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B25/00—Single-crystal growth by chemical reaction of reactive gases, e.g. chemical vapour-deposition growth
    • C30B25/02—Epitaxial-layer growth
    • C30B25/14—Feed and outlet means for the gases; Modifying the flow of the reactive gases

Definitions

  • the present invention provides an exhaust pipe after cleaning a SiC epitaxial growth furnace system including an epitaxial growth furnace for epitaxial growth of a SiC film by chemical vapor deposition (hereinafter referred to as “CVD”) and an exhaust pipe thereof with chlorine trifluoride gas.
  • CVD chemical vapor deposition
  • the present invention relates to a chlorine trifluoride cleaning residue removing method for removing chlorine trifluoride cleaning residue adhering to the inside.
  • SiC silicon carbide
  • Si silicon
  • a SiC epitaxial wafer used for such a semiconductor element is usually manufactured by epitaxially growing a SiC film on a SiC bulk single crystal substrate by CVD.
  • a susceptor holding a substrate to be processed is placed in an epitaxial growth furnace, and a silane-based gas such as monosilane (SiH 4 ) or trichlorosilane (SiHCl 3 ) is supplied as C as a source gas for supplying Si.
  • a hydrocarbon gas such as propane (C 3 H 8 ) is introduced into the growth furnace as a raw material gas for the substrate, and the substrate temperature is heated to a growth temperature necessary for epitaxial growth to epitaxially grow a SiC film on the substrate. It is to let you.
  • the treated gas after the film forming process is discharged out of the system through an exhaust pipe provided in the growth furnace.
  • SiC generated by CVD is deposited not only on the substrate surface, but also on the inner surface of the epitaxial growth furnace, the susceptor surface, and the inner surface of the exhaust pipe. For this reason, it is necessary to periodically clean the epitaxial growth furnace system including the epitaxial growth furnace and the exhaust pipe to remove these deposits at the stage when the film forming process is completed.
  • Patent Documents 1 and 2 The applicant has previously proposed Patent Documents 1 and 2 as a method for removing such chlorine trifluoride cleaning residue.
  • the device described in Patent Document 1 is such that hydrogen that is in a molecular state as a whole is passed through the processing operation system after cleaning, and the chlorine trifluoride cleaning residue is removed by this hydrogen molecule.
  • the one described in Patent Document 2 is such that a gas containing a hydrogen-containing compound such as silane, phosphine, or arsine is passed through the processing operation system after the cleaning is completed, and the chlorine trifluoride cleaning residue is removed with this hydrogen-containing compound. Is.
  • Patent Documents 1 and 2 both of the prior arts in Patent Documents 1 and 2 are such that H 2 or SiH 4 or the like is allowed to flow as the second cleaning gas after completion of cleaning with chlorine trifluoride gas, and the cleaning is substantially performed twice. Therefore, there is a problem that the cleaning process takes time and the production efficiency of the wafer is lowered. For this reason, the prior arts of Patent Documents 1 and 2 still have room for improvement.
  • An object of the present invention is to solve such a problem and efficiently remove chlorine trifluoride cleaning residue adhering to the exhaust pipe when the SiC epitaxial growth furnace system is cleaned with chlorine trifluoride gas.
  • the object is to provide a method that can be eliminated.
  • the present inventors introduced a hydrogen chloride (HCl) gas together with a raw material gas into the epitaxial growth furnace to form a SiC film, and a hydrogen system such as hydrogen molecules and hydrogen radicals generated in the process. It has been found that chlorine trifluoride cleaning residues in the exhaust pipe can be removed by the substance.
  • HCl hydrogen chloride
  • the present invention has been made based on such knowledge, and is characterized by adopting the following method.
  • the present invention is a method for removing a chlorine trifluoride cleaning residue in an exhaust pipe after cleaning an SiC epitaxial growth furnace system including an epitaxial growth furnace for performing SiC film formation and its exhaust pipe with chlorine trifluoride gas. Then, after cleaning with chlorine trifluoride gas, SiC film is formed by introducing hydrogen chloride gas together with the source gas into the epitaxial growth furnace in the SiC film forming process, and the treated gas is discharged through the exhaust pipe. By doing so, the chlorine trifluoride cleaning residue in the exhaust pipe is removed.
  • SiHCl 3 is an indispensable substance for epitaxial growth of the SiC film, but H 2 itself is not directly involved in the film formation.
  • H 2 since the H 2 molecule can remove fluorine-based contaminants, the chlorine trifluoride cleaning residue can be removed by the H 2 molecule in the same process.
  • hydrogen-based substances such as hydrogen molecules and hydrogen radicals are generated by introducing hydrogen chloride gas together with the source gas into the epitaxial growth furnace in the SiC film forming process to form the SiC film.
  • chlorine trifluoride cleaning residue in the exhaust pipe can be removed in the same process.
  • it is not necessary to remove the chlorine trifluoride cleaning residue with another cleaning gas so the time required for the cleaning process can be shortened, and the wafer The production efficiency can be increased.
  • the present invention also has the advantage that the epitaxial growth of the SiC film itself can be promoted. This is because, as described in paragraph [0045] of Patent Document 3, film growth is promoted by mixing HCl in a raw material gas for SiC epitaxial growth. Therefore, the present invention can also improve the productivity of the wafer in this respect.
  • the trifluoride adhering and remaining in the exhaust pipe can be obtained by a simple method in which hydrogen chloride gas is introduced into the epitaxial growth furnace together with the raw material gas in the SiC film forming process to form the SiC film. Since the chlorine cleaning residue can be removed, the cleaning time can be shortened and the epitaxial growth of the SiC film itself can be promoted. As a result, wafer productivity can be improved.
  • hydrogen chloride gas is introduced into the epitaxial growth furnace together with the raw material gas necessary for SiC film formation in the SiC film formation process.
  • the CVD apparatus used in the present invention mainly has a source gas supply piping system for supplying a source gas, an epitaxial growth furnace for forming a film, and an exhaust piping system for discharging a processed gas after the film formation is completed. .
  • a susceptor for holding the substrate to be processed is arranged inside the epitaxial growth furnace so that it is heated to a temperature required for film formation by a heating means such as a heating coil, a halogen lamp, or an infrared lamp. It has become.
  • the material of the epitaxial growth furnace is not particularly limited, and examples thereof include a member whose surface or gas contact surface is coated with SiC.
  • a stainless steel material can be cited, but other materials may be used.
  • the present invention can be suitably applied to materials such as Ni alloy, stainless fluororesin coating, and carbon coating.
  • the source gas is not particularly limited as long as the SiC film is epitaxially grown.
  • the source gas for supplying Si includes a silane-based gas such as monosilane (SiH 4 ) or trichlorosilane (SiHCl 3 ). Can do.
  • the source gas for C supply methane (CH 4), ethane (C 2 H 6), propane (C 3 H 8), it may be mentioned hydrocarbon gas such as neopentane (C 5 H 12) .
  • monosilane gas is preferable as the source gas for supplying Si
  • propane gas is preferable as the source gas for supplying C.
  • a doping gas may be supplied to further add a dopant.
  • hydrogen chloride gas is introduced into the epitaxial growth furnace together with the raw material gas in the SiC film forming step.
  • the method for introducing hydrogen chloride gas into the epitaxial growth furnace is not particularly limited. Both may be mixed in advance upstream of the growth furnace and supplied to the growth furnace, or may be supplied to the growth furnace through separate paths, and both may be mixed in the growth furnace.
  • An SiC film is formed on the substrate using the CVD apparatus as described above.
  • the substrate is mounted on the susceptor, the source gas is supplied through the source supply pipe, and the substrate is grown by the heating means (for example, 1400 to 1800 ° C. From the viewpoint of promoting SiC film formation, 1500 to 1800 ° C. To more preferred).
  • the heating means for example, 1400 to 1800 ° C. From the viewpoint of promoting SiC film formation, 1500 to 1800 ° C. To more preferred).
  • other film forming conditions such as the furnace pressure and gas flow rate are appropriately adjusted as necessary.
  • the SiC film forming process When the SiC film forming process is completed, SiC generated by CVD adheres to and accumulates not only on the substrate surface but also on the inner surface of the epitaxial growth furnace, the susceptor surface, and the inner surface of the exhaust pipe. Therefore, at the stage where the film forming process is completed, the epitaxial growth furnace system including the epitaxial growth furnace and the exhaust pipe is cleaned at an appropriate timing. In the present invention, such deposits are cleaned with chlorine trifluoride gas.
  • cleaning is performed by supplying chlorine trifluoride gas into the growth furnace.
  • the chlorine trifluoride gas may be used after appropriately diluted with an inert gas such as Ar.
  • An example of the temperature during cleaning with chlorine trifluoride is 400 ° C. or lower. However, it is not limited to this.
  • chlorine trifluoride gas as the cleaning gas and circulating it in the epitaxial growth furnace and the exhaust pipe, the deposits in the epitaxial growth furnace are removed.
  • chlorine trifluoride cleaning residue newly generated as a result of cleaning with chlorine trifluoride gas adheres to the inside of the exhaust pipe.
  • chlorine trifluoride cleaning residue tends to adhere.
  • hydrogen-based substances such as hydrogen molecules and hydrogen radicals are secondarily generated in this SiC film forming step.
  • the chlorine trifluoride cleaning residue in the exhaust pipe is removed.
  • the removed chlorine trifluoride cleaning residue is detoxified in a detoxifying device provided downstream of the exhaust pipe and then discharged out of the system.
  • the hydrogen chloride gas is supplied into the epitaxial growth furnace together with the raw material gas to epitaxially grow the SiC film, and the processed gas or exhaust gas used for the film forming process is simply flowed to the exhaust pipe as it is.
  • the chlorine trifluoride cleaning residue adhering and remaining in the exhaust pipe at the previous cleaning can be removed.

Abstract

The present invention reduces the cleaning time and accelerates formation of a SiC film in a SiC epitaxial growth furnace system. Provided is a method for, after a SiC epitaxial growth furnace system including an epitaxial growth furnace for formation of a SiC film and an exhaust pipe therefor is cleaned by using a chlorine trifluoride gas, removing chlorine trifluoride cleaning residues adhered to and remaining in the interior of the exhaust pipe. After the cleaning using the chlorine trifluoride gas has ended, a raw material gas and a hydrogen chloride gas are introduced together into the epitaxial growth furnace in a SiC film formation step. As a result, while the SiC film formation is performed, the gas used in the process is allowed to flow into the exhaust pipe. The gas used in the process contains hydrogen molecules, hydrogen radicals, and the like, by which chlorine trifluoride cleaning residues are removed from the interior of the exhaust pipe.

Description

ＳｉＣエピタキシャル成長炉系における三フッ化塩素クリーニング残渣除去方法Method for removing chlorine trifluoride cleaning residue in SiC epitaxial growth furnace system
　本発明は、化学的気相成長法（以下、「ＣＶＤ」という。）によりＳｉＣ膜をエピタキシャル成長させるエピタキシャル成長炉とその排気配管とを含むＳｉＣエピタキシャル成長炉系を三フッ化塩素ガスによりクリーニングした後に排気配管内に付着残留する三フッ化塩素クリーニング残渣を除去する三フッ化塩素クリーニング残渣除去方法に関する。 The present invention provides an exhaust pipe after cleaning a SiC epitaxial growth furnace system including an epitaxial growth furnace for epitaxial growth of a SiC film by chemical vapor deposition (hereinafter referred to as “CVD”) and an exhaust pipe thereof with chlorine trifluoride gas. The present invention relates to a chlorine trifluoride cleaning residue removing method for removing chlorine trifluoride cleaning residue adhering to the inside.
　炭化ケイ素（ＳｉＣ）は、ケイ素（Ｓｉ）に比べて、バンドギャップの広さ、絶縁破壊電界強度、熱伝導率などの物性値の点で優れているため、近年、半導体パワーデバイスの材料として注目されている。このような半導体素子に用いられるＳｉＣエピタキシャルウエハは、通常、ＳｉＣバルク単結晶基板上にＣＶＤによりＳｉＣ膜をエピタキシャル成長させることによって製造される。 Since silicon carbide (SiC) is superior to silicon (Si) in terms of physical properties such as wide band gap, dielectric breakdown field strength, and thermal conductivity, it has recently attracted attention as a material for semiconductor power devices. Has been. A SiC epitaxial wafer used for such a semiconductor element is usually manufactured by epitaxially growing a SiC film on a SiC bulk single crystal substrate by CVD.
　具体的には、エピタキシャル成長炉内に処理対象である基板を保持したサセプタを配置し、Ｓｉ供給用の原料ガスとしてモノシラン（ＳｉＨ４）やトリクロロシラン（ＳｉＨＣｌ３）等のシラン系ガスを、Ｃ供給用の原料ガスとしてプロパン（Ｃ３Ｈ８）等の炭化水素系ガスをそれぞれ成長炉内に導入するとともに、基板温度をエピタキシャル成長に必要な成長温度にまで加熱して、基板上にＳｉＣ膜をエピタキシャル成長させるというものである。成膜処理が終わった処理済みガスは成長炉に設けられた排気配管を通じて系外に排出される。 Specifically, a susceptor holding a substrate to be processed is placed in an epitaxial growth furnace, and a silane-based gas such as monosilane (SiH 4 ) or trichlorosilane (SiHCl 3 ) is supplied as C as a source gas for supplying Si. A hydrocarbon gas such as propane (C 3 H 8 ) is introduced into the growth furnace as a raw material gas for the substrate, and the substrate temperature is heated to a growth temperature necessary for epitaxial growth to epitaxially grow a SiC film on the substrate. It is to let you. The treated gas after the film forming process is discharged out of the system through an exhaust pipe provided in the growth furnace.
　ここで、ＣＶＤにより生成されたＳｉＣは、基板表面だけでなく、エピタキシャル成長炉の内面やサセプタ表面、排気配管の内面にも付着堆積する。このため、成膜工程が終わった段階で、エピタキシャル成長炉及び排気配管を含むエピタキシャル成長炉系を定期的にクリーニングして、これらの堆積物を除去する必要があった。 Here, SiC generated by CVD is deposited not only on the substrate surface, but also on the inner surface of the epitaxial growth furnace, the susceptor surface, and the inner surface of the exhaust pipe. For this reason, it is necessary to periodically clean the epitaxial growth furnace system including the epitaxial growth furnace and the exhaust pipe to remove these deposits at the stage when the film forming process is completed.
特公平３－４８２６８号公報Japanese Patent Publication No. 3-48268 特公平６－６３０９７号公報Japanese Patent Publication No. 6-63097 特許第４６６２０３４号公報Japanese Patent No. 4662034
　このようなクリーニング方法には様々な方法があるが、本発明者らは、プラズマを使用しないノンプラズマクリーニングとして高いクリーニング能力を有する三フッ化塩素（ＣｌＦ３）ガスを使用してＳｉＣエピタキシャル成長炉系をクリーニングすることを検討した。 Although there are various cleaning methods, the present inventors have proposed a SiC epitaxial growth reactor system using chlorine trifluoride (ClF 3 ) gas having high cleaning ability as non-plasma cleaning without using plasma. Considered cleaning.
　しかしながら、ＳｉＣエピタキシャル成長炉系を三フッ化塩素ガスによりクリーニングした場合、エピタキシャル成長炉の内部は十分にクリーニングされるものの、排気配管中にクリーニング後の残渣（本明細書において「三フッ化塩素クリーニング残渣」という。）が付着残留するという問題が生じた。本発明者らが調べたところ、これは、主に両者の素材の相違に起因することが分かった。すなわち、耐熱性が要求されるエピタキシャル成長炉は表面ないし接ガス面をＳｉＣでコーティングした部材を用いることが多いのに対し、そこまでの耐熱性が求められない排気配管は例えばステンレスを用いることが多く、これが三フッ化塩素クリーニング残渣を吸着しやすいという性質を有していたからである。 However, when the SiC epitaxial growth furnace system is cleaned with chlorine trifluoride gas, the inside of the epitaxial growth furnace is sufficiently cleaned, but the residue after cleaning in the exhaust pipe (in this specification, “chlorine trifluoride cleaning residue” )) Remained. When the present inventors examined, it turned out that this originates mainly in the difference of both raw materials. That is, an epitaxial growth furnace that requires heat resistance often uses a member whose surface or gas contact surface is coated with SiC, whereas exhaust pipes that do not require heat resistance are often made of stainless steel, for example. This is because this has the property of easily adsorbing the chlorine trifluoride cleaning residue.
　このような三フッ化塩素クリーニング残渣を除去する方法として、出願人は過去に特許文献１及び２を提案している。特許文献１に記載のものは、クリーニング終了後の処理操作系に全体が分子状態にある水素を流し、この水素分子で三フッ化塩素クリーニング残渣を除去するというものである。また、特許文献２に記載のものは、クリーニング終了後の処理操作系にシラン、ホスフィン、アルシン等の水素含有化合物のガスを流して、この水素含有化合物で三フッ化塩素クリーニング残渣を除去するというものである。 The applicant has previously proposed Patent Documents 1 and 2 as a method for removing such chlorine trifluoride cleaning residue. The device described in Patent Document 1 is such that hydrogen that is in a molecular state as a whole is passed through the processing operation system after cleaning, and the chlorine trifluoride cleaning residue is removed by this hydrogen molecule. In addition, the one described in Patent Document 2 is such that a gas containing a hydrogen-containing compound such as silane, phosphine, or arsine is passed through the processing operation system after the cleaning is completed, and the chlorine trifluoride cleaning residue is removed with this hydrogen-containing compound. Is.
　しかし、特許文献１及び２の従来技術はいずれも、三フッ化塩素ガスによるクリーニング終了後に第２のクリーニングガスとしてＨ２又はＳｉＨ４等を流すというものであり、実質的にクリーニングを２回行うに等しいため、クリーニングプロセスに時間を要し、ウエハの製造効率が低下するという問題があった。このため、特許文献１及び２の従来技術は依然改良の余地があった。 However, both of the prior arts in Patent Documents 1 and 2 are such that H 2 or SiH 4 or the like is allowed to flow as the second cleaning gas after completion of cleaning with chlorine trifluoride gas, and the cleaning is substantially performed twice. Therefore, there is a problem that the cleaning process takes time and the production efficiency of the wafer is lowered. For this reason, the prior arts of Patent Documents 1 and 2 still have room for improvement.
　本発明は、かかる課題を解決することを目的とするものであり、ＳｉＣエピタキシャル成長炉系を三フッ化塩素ガスによりクリーニングしたときに排気配管中に付着残留する三フッ化塩素クリーニング残渣を効率的に除去することができる方法を提供することを目的とする。 An object of the present invention is to solve such a problem and efficiently remove chlorine trifluoride cleaning residue adhering to the exhaust pipe when the SiC epitaxial growth furnace system is cleaned with chlorine trifluoride gas. The object is to provide a method that can be eliminated.
　本発明者らは、ＳｉＣ成膜工程においてエピタキシャル成長炉内に原料ガスとともに塩化水素（ＨＣｌ）ガスを導入してＳｉＣの成膜を行うと、その過程で発生した水素分子や水素ラジカル等の水素系物質により排気配管中の三フッ化塩素クリーニング残渣を除去できることを見出した。 In the SiC film forming process, the present inventors introduced a hydrogen chloride (HCl) gas together with a raw material gas into the epitaxial growth furnace to form a SiC film, and a hydrogen system such as hydrogen molecules and hydrogen radicals generated in the process. It has been found that chlorine trifluoride cleaning residues in the exhaust pipe can be removed by the substance.
　本発明は、かかる知見に基づいてなされたものであり、以下のような方法を採用したことを特徴とする。 The present invention has been made based on such knowledge, and is characterized by adopting the following method.
　すなわち、本発明は、ＳｉＣ成膜を行うエピタキシャル成長炉とその排気配管とを含むＳｉＣエピタキシャル成長炉系を三フッ化塩素ガスによりクリーニングした後の排気配管内の三フッ化塩素クリーニング残渣を除去する方法であって、三フッ化塩素ガスによるクリーニング終了後、ＳｉＣ成膜工程においてエピタキシャル成長炉内に原料ガスとともに塩化水素ガスを導入することによりＳｉＣの成膜を行うとともに、その処理済みガスを排気配管を通じて排出することにより同排気配管内の三フッ化塩素クリーニング残渣を除去することを特徴とするものである。 That is, the present invention is a method for removing a chlorine trifluoride cleaning residue in an exhaust pipe after cleaning an SiC epitaxial growth furnace system including an epitaxial growth furnace for performing SiC film formation and its exhaust pipe with chlorine trifluoride gas. Then, after cleaning with chlorine trifluoride gas, SiC film is formed by introducing hydrogen chloride gas together with the source gas into the epitaxial growth furnace in the SiC film forming process, and the treated gas is discharged through the exhaust pipe. By doing so, the chlorine trifluoride cleaning residue in the exhaust pipe is removed.
　塩化水素は熱分解し難く、１８００℃で０．２２％程度しか分解しないとされている。しかし、Ｓｉと共存させることによりＳｉＨＣｌ３等への変換が進行するとともに、Ｈ２が発生する。具体的には、ＳｉＣ成膜工程においてエピタキシャル成長炉内に原料ガスとともに塩化水素ガスを導入してＳｉＣの成膜を行うと、以下のような反応により、ＳｉＨＣｌ３とともに、副次的にＨ２が発生する。
　Ｓｉ＋３ＨＣｌ→ＳｉＨＣｌ３＋Ｈ２ It is said that hydrogen chloride is difficult to thermally decompose and decomposes only about 0.22% at 1800 ° C. However, when coexisting with Si, conversion to SiHCl 3 or the like proceeds and H 2 is generated. Specifically, when SiC film formation is performed by introducing hydrogen chloride gas together with the source gas into the epitaxial growth furnace in the SiC film formation process, the following reaction causes H 2 to be added as a subordinate together with SiHCl 3. appear.
Si + 3HCl → SiHCl 3 + H 2
　このうち、ＳｉＨＣｌ３はＳｉＣ膜のエピタキシャル成長に不可欠の物質であるが、Ｈ２自体は成膜には直接関与しない。しかし、特許文献１に示すとおり、Ｈ２分子はフッ素系汚染物質を除去できるため、このＨ２分子によって三フッ化塩素クリーニング残渣を同じプロセスの中で除去することができる。 Of these, SiHCl 3 is an indispensable substance for epitaxial growth of the SiC film, but H 2 itself is not directly involved in the film formation. However, as shown in Patent Document 1, since the H 2 molecule can remove fluorine-based contaminants, the chlorine trifluoride cleaning residue can be removed by the H 2 molecule in the same process.
　なお、上記の反応式ではＨ２の発生しか示されていないが、ＳｉＣ成膜の過程で水素ラジカルや水素イオン等の活性種の発生も考えられる。このような活性種であってもフッ素系汚染物質を除去できることは、特許文献１の従来技術欄（第２欄第５～最終行）に記載されているとおりである。したがって、本発明における三フッ化塩素クリーニング残渣の除去は、必ずしもＨ２分子による場合のみに限定されるものではない。 In the above reaction scheme is only shown the generation of H 2, generation of active species of the hydrogen radicals and hydrogen ions in the course of the SiC deposition is also conceivable. As described in the prior art column (column 2, column 5 to the last row) of Patent Document 1, it is possible to remove fluorine-based contaminants even with such active species. Therefore, the removal of the chlorine trifluoride cleaning residue in the present invention is not necessarily limited only to the case of using H 2 molecules.
　このように、本発明では、ＳｉＣ成膜工程においてエピタキシャル成長炉内に原料ガスとともに塩化水素ガスを導入してＳｉＣの成膜を行うことにより水素分子や水素ラジカル等の水素系物質が発生するので、これによって排気配管中の三フッ化塩素クリーニング残渣を同じプロセスの中で除去することができる。言い換えれば、三フッ化塩素ガスによりＳｉＣエピタキシャル成長炉系をクリーニングした後、別のクリーニングガスにより三フッ化塩素クリーニング残渣を除去する必要がないため、クリーニングプロセスに要する時間を短縮することができ、ウエハの製造効率を上げることができる。 As described above, in the present invention, hydrogen-based substances such as hydrogen molecules and hydrogen radicals are generated by introducing hydrogen chloride gas together with the source gas into the epitaxial growth furnace in the SiC film forming process to form the SiC film. Thereby, chlorine trifluoride cleaning residue in the exhaust pipe can be removed in the same process. In other words, after cleaning the SiC epitaxial growth furnace system with chlorine trifluoride gas, it is not necessary to remove the chlorine trifluoride cleaning residue with another cleaning gas, so the time required for the cleaning process can be shortened, and the wafer The production efficiency can be increased.
　以上に加えて、本発明ではさらにＳｉＣ膜のエピタキシャル成長自体を促進することできるというメリットもある。特許文献３の段落［００４５］に記載されているとおり、ＳｉＣエピタキシャル成長の原料ガス中にＨＣｌを混合することにより膜成長が促進されるからである。したがって、本発明は、この点でもウエハの生産性を向上させることができる。 In addition to the above, the present invention also has the advantage that the epitaxial growth of the SiC film itself can be promoted. This is because, as described in paragraph [0045] of Patent Document 3, film growth is promoted by mixing HCl in a raw material gas for SiC epitaxial growth. Therefore, the present invention can also improve the productivity of the wafer in this respect.
　以上のとおり、本発明によれば、ＳｉＣ成膜工程においてエピタキシャル成長炉内に原料ガスとともに塩化水素ガスを導入してＳｉＣ成膜を行うという簡単な方法によって、排気配管内に付着残留した三フッ化塩素クリーニング残渣を除去することができるので、クリーニング時間を短縮できるとともに、ＳｉＣ膜のエピタキシャル成長自体を促進することできるという効果を奏する。
　この結果、ウエハの生産性を向上させることができる。 As described above, according to the present invention, the trifluoride adhering and remaining in the exhaust pipe can be obtained by a simple method in which hydrogen chloride gas is introduced into the epitaxial growth furnace together with the raw material gas in the SiC film forming process to form the SiC film. Since the chlorine cleaning residue can be removed, the cleaning time can be shortened and the epitaxial growth of the SiC film itself can be promoted.
As a result, wafer productivity can be improved.
　以下、本発明の実施形態について説明する。 Hereinafter, embodiments of the present invention will be described.
　本発明は、三フッ化塩素ガスによるクリーニング終了後、ＳｉＣ成膜工程において、エピタキシャル成長炉内に、ＳｉＣ成膜に必要な原料ガスとともに塩化水素ガスを導入するというものである。 In the present invention, after the cleaning with chlorine trifluoride gas is completed, hydrogen chloride gas is introduced into the epitaxial growth furnace together with the raw material gas necessary for SiC film formation in the SiC film formation process.
　本発明に使用されるＣＶＤ装置は、主に、原料ガスを供給する原料ガス供給配管系と、膜形成を行うエピタキシャル成長炉と、膜形成終了後の処理済みガスを排出する排気配管系とを有する。 The CVD apparatus used in the present invention mainly has a source gas supply piping system for supplying a source gas, an epitaxial growth furnace for forming a film, and an exhaust piping system for discharging a processed gas after the film formation is completed. .
　エピタキシャル成長炉の内部には、処理対象である基板を保持するためのサセプタが配置されており、加熱コイルやハロゲンランプ、赤外線ランプ等の加熱手段により成膜に必要な温度にまで加熱されるようになっている。 A susceptor for holding the substrate to be processed is arranged inside the epitaxial growth furnace so that it is heated to a temperature required for film formation by a heating means such as a heating coil, a halogen lamp, or an infrared lamp. It has become.
　エピタキシャル成長炉の素材は特に限定されないが、一例として、表面ないし接ガス面をＳｉＣでコーティングした部材を挙げることができる。また、排気配管の素材としては、一例としてステンレス製のものを挙げることができるが、それ以外のものであってもよい。ステンレス以外の素材としては、例えばＮｉ合金や、ステンレスのフッ素樹脂コーティング、カーボンコーティングといった素材でも本発明が好適に適用できる。 The material of the epitaxial growth furnace is not particularly limited, and examples thereof include a member whose surface or gas contact surface is coated with SiC. Moreover, as an example of the material of the exhaust pipe, a stainless steel material can be cited, but other materials may be used. As a material other than stainless steel, for example, the present invention can be suitably applied to materials such as Ni alloy, stainless fluororesin coating, and carbon coating.
　原料ガスとしては、ＳｉＣ膜をエピタキシャル成長させるものであれば特に限定されないが、好ましくは、Ｓｉ供給用の原料ガスとして、モノシラン（ＳｉＨ４）、トリクロロシラン（ＳｉＨＣｌ３）等のシラン系ガスを挙げることができる。また、Ｃ供給用の原料ガスとして、メタン（ＣＨ４）、エタン（Ｃ２Ｈ６）、プロパン（Ｃ３Ｈ８）、ネオペンタン（Ｃ５Ｈ１２）等の炭化水素系ガスを挙げることができる。このうち、Ｓｉ供給用の原料ガスとしてはモノシランガスが好ましく、Ｃ供給用の原料ガスとしてはプロパンガスが好ましい。本発明においては、さらにドーパントを添加するためにドーピングガスを供給してもよい。 The source gas is not particularly limited as long as the SiC film is epitaxially grown. Preferably, the source gas for supplying Si includes a silane-based gas such as monosilane (SiH 4 ) or trichlorosilane (SiHCl 3 ). Can do. Further, as the source gas for C supply, methane (CH 4), ethane (C 2 H 6), propane (C 3 H 8), it may be mentioned hydrocarbon gas such as neopentane (C 5 H 12) . Of these, monosilane gas is preferable as the source gas for supplying Si, and propane gas is preferable as the source gas for supplying C. In the present invention, a doping gas may be supplied to further add a dopant.
　本発明では、ＳｉＣ成膜工程において、エピタキシャル成長炉内に原料ガスとともに塩化水素ガスを導入する。エピタキシャル成長炉内に塩化水素ガスを導入する方法は特に限定されない。成長炉の上流で予め両者を混合して成長炉内に供給してもよいし、別々の経路で成長炉に供給し、成長炉内で両者を混合してもよい。 In the present invention, hydrogen chloride gas is introduced into the epitaxial growth furnace together with the raw material gas in the SiC film forming step. The method for introducing hydrogen chloride gas into the epitaxial growth furnace is not particularly limited. Both may be mixed in advance upstream of the growth furnace and supplied to the growth furnace, or may be supplied to the growth furnace through separate paths, and both may be mixed in the growth furnace.
　以上のようなＣＶＤ装置を使用して基板上にＳｉＣ膜を形成する。それには、サセプタに基板を装着し、原料供給配管を通して原料ガスを供給するとともに、加熱手段により基板を成長温度（一例としては１４００～１８００℃。ＳｉＣ成膜を促進する観点からは１５００～１８００℃がさらに好ましい）まで加熱する。また、必要に応じて炉内圧力やガス流量等の他の成膜条件についても適宜調整する。このようにして基板表面に原料ガスを接触させることで、基板表面にＳｉＣ膜をエピタキシャル成長させることができる。成膜処理が終了した処理済みガスないし排ガスは排気配管を通じて排出する。 An SiC film is formed on the substrate using the CVD apparatus as described above. For this purpose, the substrate is mounted on the susceptor, the source gas is supplied through the source supply pipe, and the substrate is grown by the heating means (for example, 1400 to 1800 ° C. From the viewpoint of promoting SiC film formation, 1500 to 1800 ° C. To more preferred). In addition, other film forming conditions such as the furnace pressure and gas flow rate are appropriately adjusted as necessary. By bringing the source gas into contact with the substrate surface in this way, the SiC film can be epitaxially grown on the substrate surface. The treated gas or exhaust gas after the film forming process is exhausted through the exhaust pipe.
　ＳｉＣ成膜工程が終了すると、ＣＶＤにより生成されたＳｉＣは、基板表面だけでなく、エピタキシャル成長炉の内面やサセプタ表面、排気配管の内面にも付着堆積する。そこで、成膜工程が終わった段階で、エピタキシャル成長炉及び排気配管を含むエピタキシャル成長炉系を適宜タイミングでクリーニングする。本発明では、かかる堆積物を三フッ化塩素ガスによってクリーニングする。 When the SiC film forming process is completed, SiC generated by CVD adheres to and accumulates not only on the substrate surface but also on the inner surface of the epitaxial growth furnace, the susceptor surface, and the inner surface of the exhaust pipe. Therefore, at the stage where the film forming process is completed, the epitaxial growth furnace system including the epitaxial growth furnace and the exhaust pipe is cleaned at an appropriate timing. In the present invention, such deposits are cleaned with chlorine trifluoride gas.
　三フッ化塩素ガスによってクリーニングするに当たっては、成膜が完了した基板（ウエハ）を取り出した後、成長炉内に三フッ化塩素ガスを供給することによりクリーニングを行う。三フッ化塩素ガスは、適宜Ａｒ等の不活性ガスで希釈させて使用してもよい。三フッ化塩素によるクリーニング時の温度の一例としては４００℃以下である。但し、これに限定されない。 In cleaning with chlorine trifluoride gas, after removing the substrate (wafer) after film formation, cleaning is performed by supplying chlorine trifluoride gas into the growth furnace. The chlorine trifluoride gas may be used after appropriately diluted with an inert gas such as Ar. An example of the temperature during cleaning with chlorine trifluoride is 400 ° C. or lower. However, it is not limited to this.
　このように、クリーニングガスとして三フッ化塩素ガスを使用して、これをエピタキシャル成長炉及び排気配管内に流通させることにより、エピタキシャル成長炉内の堆積物は除去されることになる。しかし、他方で、排気配管の内部には新たに三フッ化塩素ガスによるクリーニングの結果生じた三フッ化塩素クリーニング残渣が付着する。特に排気配管がステンレス製の場合は、三フッ化塩素クリーニング残渣が付着しやすい。 As described above, by using chlorine trifluoride gas as the cleaning gas and circulating it in the epitaxial growth furnace and the exhaust pipe, the deposits in the epitaxial growth furnace are removed. However, on the other hand, chlorine trifluoride cleaning residue newly generated as a result of cleaning with chlorine trifluoride gas adheres to the inside of the exhaust pipe. In particular, when the exhaust pipe is made of stainless steel, chlorine trifluoride cleaning residue tends to adhere.
　しかし、本発明では、かかる三フッ化塩素クリーニング残渣は次回のＳｉＣ成膜工程において除去されることになる。このため、本発明では、必要な時間クリーニングガスを流した後、次のウエハの製造（ＳｉＣエピタキシャル膜の形成）に取り掛かる。すなわち、新たな基板を成長炉内に配置して次回の成膜の準備を行い、すべての準備が整った後、改めてエピタキシャル成長炉内に原料ガスとともに塩化水素ガスを導入して基板上にＳｉＣエピタキシャル膜を形成する。そして、成膜処理が終了した処理済みガスないし排ガスを排気配管を通じて炉外に排出する。 However, in the present invention, such chlorine trifluoride cleaning residue is removed in the next SiC film forming step. For this reason, in this invention, after flowing cleaning gas for the required time, it starts to manufacture the next wafer (formation of a SiC epitaxial film). In other words, a new substrate is placed in the growth furnace to prepare for the next film formation. After all the preparations have been made, a hydrogen chloride gas is introduced into the epitaxial growth furnace together with the source gas, and the SiC epitaxial is formed on the substrate. A film is formed. Then, the processed gas or exhaust gas after the film forming process is exhausted to the outside of the furnace through the exhaust pipe.
　本発明では、このＳｉＣ成膜工程において水素分子や水素ラジカル等の水素系物質が副次的に発生する。この水素系物質を処理済みガスとともに排気配管に流すことにより、排気配管内の三フッ化塩素クリーニング残渣が除去されることになる。除去された三フッ化塩素クリーニング残渣は、排気配管の下流に設けられた除害装置において無害化されてから、系外に排出されることになる。 In the present invention, hydrogen-based substances such as hydrogen molecules and hydrogen radicals are secondarily generated in this SiC film forming step. By flowing this hydrogen-based material through the exhaust pipe together with the treated gas, the chlorine trifluoride cleaning residue in the exhaust pipe is removed. The removed chlorine trifluoride cleaning residue is detoxified in a detoxifying device provided downstream of the exhaust pipe and then discharged out of the system.
　このように、本発明では、エピタキシャル成長炉内に原料ガスとともに塩化水素ガスを供給してＳｉＣ膜をエピタキシャル成長させつつ、その成膜処理に使用した処理済みガスないし排ガスをそのまま排気配管に流すという簡単な方法により、前回のクリーニング時に排気配管内に付着残留した三フッ化塩素クリーニング残渣を除去することができる。 As described above, in the present invention, the hydrogen chloride gas is supplied into the epitaxial growth furnace together with the raw material gas to epitaxially grow the SiC film, and the processed gas or exhaust gas used for the film forming process is simply flowed to the exhaust pipe as it is. By this method, the chlorine trifluoride cleaning residue adhering and remaining in the exhaust pipe at the previous cleaning can be removed.

Claims (1)

  1. 　ＳｉＣ成膜を行うエピタキシャル成長炉とその排気配管とを含むＳｉＣエピタキシャル成長炉系を三フッ化塩素ガスによりクリーニングした後の排気配管内の三フッ化塩素クリーニング残渣を除去する方法であって、
    　三フッ化塩素ガスによるクリーニング終了後、ＳｉＣ成膜工程においてエピタキシャル成長炉内に原料ガスとともに塩化水素ガスを導入することによりＳｉＣの成膜を行うとともに、その処理済みガスを排気配管を通じて排出することにより同排気配管内の三フッ化塩素クリーニング残渣を除去することを特徴とする、ＳｉＣエピタキシャル成長炉系における三フッ化塩素クリーニング残渣除去方法。     A method for removing chlorine trifluoride cleaning residues in an exhaust pipe after cleaning an SiC epitaxial growth furnace system including an epitaxial growth furnace for performing SiC film formation and its exhaust pipe with chlorine trifluoride gas,
    After completion of cleaning with chlorine trifluoride gas, SiC film is formed by introducing hydrogen chloride gas together with the raw material gas into the epitaxial growth furnace in the SiC film forming process, and the treated gas is discharged through the exhaust pipe A method for removing chlorine trifluoride cleaning residues in a SiC epitaxial growth furnace system, comprising removing chlorine trifluoride cleaning residues in the exhaust pipe.
PCT/JP2016/077330 2016-09-15 2016-09-15 Method for removing chlorine trifluoride cleaning residues in sic epitaxial growth furnace system WO2018051472A1 (en)

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JP2012080035A (en) * 2010-10-06 2012-04-19 Hitachi Kokusai Electric Inc Substrate processing device and substrate manufacturing method
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JP2014179550A (en) * 2013-03-15 2014-09-25 Hitachi Kokusai Electric Inc Substrate processing apparatus

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JP2012080035A (en) * 2010-10-06 2012-04-19 Hitachi Kokusai Electric Inc Substrate processing device and substrate manufacturing method
JP2012175072A (en) * 2011-02-24 2012-09-10 Hitachi Kokusai Electric Inc Substrate processing apparatus
JP2014179550A (en) * 2013-03-15 2014-09-25 Hitachi Kokusai Electric Inc Substrate processing apparatus

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