Classifications

• • 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
  • C23C16/458—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 characterised by the method used for supporting substrates in the reaction chamber
  • C23C16/4581—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 characterised by the method used for supporting substrates in the reaction chamber characterised by material of construction or surface finish of the means for supporting the substrate
• • 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
  • C30B25/12—Substrate holders or susceptors

Definitions

• the present invention relates to a method for manufacturing a susceptor built up of a core.
• the present invention furthermore relates to such a susceptor, as well as to a method for depositing active layers on a semiconductor substrate, wherein a semiconductor substrate is placed on a susceptor in a deposition reactor and one or more reactive gases are supplied to said deposition reactor for the purpose of forming one or more active layers on the semiconductor substrate.
• Such a susceptor is known per se, for example from US patents nos. 3,980,854 and 4,047,496.
• Such susceptors are in particular suitable for depositing epitaxial layers of semiconductor material on substrate wafers, for example for producing semiconductor devices, such as integrated circuits.
• an epitaxial layer of silicon on a substrate wafer of silicon for example, is used as a starting material.
• the epitaxial layer of silicon is deposited upon the silicon wafer in a chemical vapour deposition process (CVD) wherein the wafer is heated and the layer of silicon is deposited from the vapour reaction product of a chemical reaction.
• CVD chemical vapour deposition process
• the silicon wafers are placed on graphite susceptors, and the susceptors are heated by means of high-frequency energy or infrared lamps, after which silicon is deposited from the vapour state not only on the wafers but also on the susceptors.
• Other semiconductor production processes wherein susceptors are used are diffusion and oxidation processes and chemical vapour deposition (CVD) processes for depositing polysilicon and dielectric layers, such as Si0 2 , Si 3 N 4 , Si0 x N y and conductive layers such as Si x , TiN, TaN en TaO.
• CVD chemical vapour deposition
• susceptors are manufactured at a location different from the location where they are used in such a deposition reactor, so that there is a significant risk of contamination of the susceptor surface during the period between production and use of the susceptors.
• the surface can thus be contaminated undesirably during the various stages of the production process, for example during cooling, during unloading, during internal transport, during quality inspection, during packing, during storage and during transport in the package, as well as during the mounting of the susceptor in the reactor where it is to be used in the manufacture of the semiconductor devices.
• a susceptor built up of a core which susceptor is insensitive to contaminations - from outside, in particular during the period between the manufacture of the susceptor and the actual positioning of the susceptor in a production process for manufacturing semiconductor devices, such as substrate wafers.
• the method referred to in the introduction is according to the present invention characterized in that a coating selected from the group consisting of SiC and A1N is deposited on the core in a deposition reactor, on which coating a protective layer having a chemical composition which comprises one or more of the elements Si, 0, C and N, differently from the chemical composition of the coating, is subsequently deposited, for the purpose of obtaining the susceptor.
• the step of depositing the coating and the step of depositing the protective layer are carried out without interruptions during the deposition process for obtaining the susceptor, which in particular means that the core is not removed from the deposition reactor between the deposition steps for the coating and the protective layer. Since the core remains present in the deposition reactor in such a situation, the risk of interim contamination from outside is minimized. In a specific embodiment it is also possible, on the other hand, to deposit the coating and the protective layer in separate reactors.
• the present inventors assume that the provision of the protective layer causes any contaminations that are present in the coating to migrate from the coating to the protective coating as a result of diffusion, so that the use of the present invention even leads to a coating which is "purer" than that of the susceptor that is known from the prior art. Since the prior art susceptor does not have the present protective layer, any contaminations that are present on the surface of the coating will diffuse in the direction of the core, so that the current state of the art leads to a "contaminated" susceptor, which is undesirable for manufacturing semiconductor substrates.
• Suitable materials for the protective layer are: Si0 2 , Si 3 N 4 , SiO x N y or Si, or a combination of one or more thereof.
• the core is preferably selected from the group consisting of graphite, SiC and SiC with a silicon dope, or a combination thereof.
• the deposition of the coating preferably takes place by means of a chemical vapour deposition process, wherein in particular a coating of SiC is obtained on the core by reacting a silicon-containing precursor, with the possible addition of a hydrocarbon compound, at a temperature of 1000 - 1500 °C and a pressure of 10 - 1000 mbar, whereby the layer thickness of SiC ranges between 1 - 4000 ⁇ m.
• a suitable precursor is in particular methyl trichlorosi lane in the presence of argon and/or hydrogen.
• the deposition of a coating of A1N on the core preferably takes place by reacting aluminium trichloride and ammonia, possibly in the presence of argon, hydrogen and/or nitrogen, at a temperature of 600 - 1000 °C and a pressure of 10 - 1000 mbar, whereby the layer thickness of A1N ranges between 1 - 4000 ⁇ m.
• the protective layer is preferably provided by means of a chemical vapour deposition process, wherein a silicon-containing precursor, to which a carbonaceous precursor, hydrogen and/or chlorine may be added, is deposited on the coating that is already present in a thickness of up to 100 ⁇ m at a temperature of 1000 - 1500 °C and a pressure of 10 - 1000 mbar.
• the present invention furthermore relates to a susceptor built up of a core, which susceptor is according to the present invention characterized in that said core has successively been provided with a coating selected from the group consisting of SiC and A1N and with a protective coating present on said coating, whose chemical composition comprises one or more of the elements Si, 0, C and N, differently from the chemical composition of the coating, so as to obtain the susceptor. It is in particular preferable not to remove the core from the deposition reactor between the step of depositing the coating and the step of depositing the protective coating.
• a particularly preferred thickness of the coating is 1 - 4000 ⁇ m, whereby the protective layer preferably has a thickness of up to 100 ⁇ m. A thickness greater than said upper limit does not have an additional effect.
• the present invention furthermore relates to a method for depositing active layers on a semiconductor substrate, wherein a semiconductor substrate is placed on a susceptor in a deposition reactor and one or more reactive gases are supplied to the deposition reactor so as to form one or more active layers on the semiconductor substrate, which method is according to the present invention characterized in that it comprises the following steps: i) positioning the present susceptor, or the susceptor obtained in accordance with the present method, in the deposition reactor; ii) removing the protective layer from the susceptor by means of an etching process; iii) placing the semiconductor substrate on the susceptor from which the protective layer has been removed; and iv) supplying one or more reactive gases so as to form one or more active layers on the semiconductor substrate, wherein steps i) - iv) are
• steps i) - iv) are carried out in the same deposition reactor without interruptions, the risk of contaminations is minimized, so that the quality of the semiconductor substrate thus produced is high.
• the term "without interruptions" as used herein is understood to mean that no contact with the environment outside the deposition reactor is possible between the step of removing the protective layer from the susceptor by means of an etching process and the step of subsequently placing the semiconductor substrate thereon. The fact is that such contact is experienced as being disadvantageous for the purity of the clean susceptor surface that is obtained after the etching step.
• step ii) it is in particular preferable to carry out step ii) by using a halogen-containing gas, at a temperature ranging between 100 - 1300 ° C, possibly with plasma activation.
• the present invention in particular comprises the successive deposition of a coating and a protective layer directly onto a core, as a result of which the presence of any contaminations on the coating surface is minimized, which protective layer is finally removed from the susceptor at the time of the actual production of the desired semiconductor substrate.

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

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Cited By (13)

Citations (8)

• 2000
  • 2000-06-28 NL NL1015550A patent/NL1015550C2/nl not_active IP Right Cessation
• 2001
  • 2001-05-31 WO PCT/NL2001/000432 patent/WO2002000968A1/en active Application Filing
  • 2001-06-01 AU AU2001264411A patent/AU2001264411A1/en not_active Abandoned

Patent Citations (8)

Non-Patent Citations (2)

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