WO2009093417A1 - Susceptor and vapor phase growth system and vapor phase growth method - Google Patents

Susceptor and vapor phase growth system and vapor phase growth method Download PDF

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Publication number
WO2009093417A1
WO2009093417A1 PCT/JP2009/000098 JP2009000098W WO2009093417A1 WO 2009093417 A1 WO2009093417 A1 WO 2009093417A1 JP 2009000098 W JP2009000098 W JP 2009000098W WO 2009093417 A1 WO2009093417 A1 WO 2009093417A1
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WO
WIPO (PCT)
Prior art keywords
wafer
counterbore
susceptor
vapor phase
phase growth
Prior art date
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PCT/JP2009/000098
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French (fr)
Japanese (ja)
Inventor
Yoshio Hagiwara
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Shin-Etsu Handotai Co., Ltd.
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Application filed by Shin-Etsu Handotai Co., Ltd. filed Critical Shin-Etsu Handotai Co., Ltd.
Publication of WO2009093417A1 publication Critical patent/WO2009093417A1/en

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    • 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
    • C23C16/4582—Rigid and flat substrates, e.g. plates or discs
    • C23C16/4583—Rigid and flat substrates, e.g. plates or discs the substrate being supported substantially horizontally
    • C23C16/4584—Rigid and flat substrates, e.g. plates or discs the substrate being supported substantially horizontally the substrate being rotated
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/683—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L21/687—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using mechanical means, e.g. chucks, clamps or pinches
    • H01L21/68714—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using mechanical means, e.g. chucks, clamps or pinches the wafers being placed on a susceptor, stage or support
    • H01L21/68728—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using mechanical means, e.g. chucks, clamps or pinches the wafers being placed on a susceptor, stage or support characterised by a plurality of separate clamping members, e.g. clamping fingers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/683—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L21/687—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using mechanical means, e.g. chucks, clamps or pinches
    • H01L21/68714—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using mechanical means, e.g. chucks, clamps or pinches the wafers being placed on a susceptor, stage or support
    • H01L21/68735—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using mechanical means, e.g. chucks, clamps or pinches the wafers being placed on a susceptor, stage or support characterised by edge profile or support profile

Definitions

  • the present invention relates to a susceptor for horizontally placing a wafer in a vapor phase growth apparatus used for vapor phase growth of a thin film on a wafer, and further relates to a vapor phase growth apparatus and a vapor phase growth method using the same. .
  • a process of forming a thin film on a semiconductor substrate by supplying a reactive gas onto a semiconductor substrate (hereinafter also simply referred to as a wafer) that is blocked from the outside by a container.
  • a vapor phase growth apparatus is used that forms a thin film by causing a gas phase reaction on a semiconductor substrate by supplying a raw material gas.
  • an epitaxial layer growth apparatus for growing a single crystal of silicon on a silicon substrate is used in a manufacturing process of a semiconductor device such as an LSI (Large Scale Integrated Circuit).
  • a silicon substrate is usually heated to 1000 ° C. or more, a mixed gas of a raw material gas such as silicon tetrachloride and trichlorosilane and hydrogen is supplied into a reaction vessel, and hydrogen reduction or thermal decomposition is performed on the silicon substrate.
  • a single crystal silicon thin film is grown by epitaxial growth. Epitaxial growth is used to increase the breakdown voltage of bipolar devices in the manufacturing process of semiconductor devices. When manufacturing megabit memories in devices, it is a necessary technology to prevent soft errors and latch-up caused by alpha rays. It has become.
  • FIG. 5 is a schematic view showing a conventional vapor phase growth apparatus.
  • reference numeral 50 denotes a vapor phase growth apparatus.
  • the vapor phase growth apparatus 50 is isolated from the outside by a quartz chamber 51 and a chamber base 52.
  • a support base 53 that supports a disc-shaped susceptor 56 is rotatably disposed in the center of the chamber 51, and in use, a plurality of semiconductor substrates 55 are placed horizontally on the susceptor 56 with the growth surface up. Then, vapor phase growth is performed.
  • the central portion of the support base 53 is a source gas introduction portion 57, and the lower portion of the support base 53 protrudes below the chamber base 52.
  • a source gas nozzle 58 for supplying a gas containing a source material for forming a thin film is connected to an opening 56a in the center of the susceptor 56.
  • the source gas nozzle 58 has a plurality of holes 58 a so that the source gas flows out substantially parallel to the upper surface of the semiconductor substrate 55.
  • a source gas discharge port 59 is formed near the center of the chamber base 52, that is, around the support base 53.
  • an induction heating coil 54 is installed in a spiral shape below the susceptor 56 in order to heat the semiconductor substrate.
  • FIG. 4 is a view showing an outline of a conventional single-sheet holding type susceptor.
  • the conventional susceptor 40 has a disk shape in which, for example, a graphite substrate is coated with a SiC film having a thickness of about 150 ⁇ m by a CVD method, and a circular portion having a diameter approximately the same as the diameter of the wafer W at the center thereof.
  • a concave counterbore 41 is formed.
  • the outside of the counterbore 41 is raised one step higher to prevent the wafer W from being displaced in the horizontal direction from the rotating susceptor 40 during vapor phase growth. That is, the portion of the counterbore side wall is a positioning means in the susceptor of the wafer. Therefore, a portion that is one step higher than the bottom surface of the counterbore is called a counterbore guide 42 for convenience.
  • the susceptor of Japanese Patent Application Laid-Open No. 2004-319623 is a type that holds one wafer as shown in FIG. 4, but an inclined surface not shown in FIG. 4 is formed on the outer periphery of the counterbore. The wafer outer peripheral end is held by this inclined surface so that the wafer is not damaged.
  • the shape of the counterbore of the susceptor in Japanese Patent Application Laid-Open No. 6-310442 has a flat bottom surface, and the counterbore guide that is raised by one step from the bottom surface of the counterbore has a convex portion having a rectangular cross section surrounding the outer periphery.
  • the flow of the raw material gas is rectified by the convex portions on the counterbored guide, and the film thickness of the thin film to be vapor-phase grown on the wafer is made uniform.
  • the film thickness varies within the wafer surface, and it is difficult to form a thin film so as to be even more uniform.
  • the present invention has been made in view of such problems.
  • a thin film is vapor-phase grown on a wafer using a vapor phase growth apparatus
  • the uniformity of the film thickness in the wafer surface of the thin film to be formed is improved.
  • the present invention provides a susceptor in which a counterbore for horizontally placing a wafer in a vapor phase growth apparatus is formed.
  • the counterbore is a circular concave shape having a bottom surface and a side wall, The diameter of the counterbore side wall is larger than the diameter of the wafer to be placed,
  • a susceptor is provided, wherein a plurality of protrusions are formed on a bottom surface of the counterbore so as to protrude from the bottom surface of the counterbore so that the wafer is placed in a central portion of the counterbore.
  • the diameter of the side wall of the counterbore is larger than the diameter of the wafer to be mounted, and the bottom surface of the counterbore protrudes from the bottom surface of the counterbore so that the wafer is mounted at the center portion of the counterbore.
  • a plurality of protrusions are formed. Since the diameter of the counterbore side wall is larger than the diameter of the wafer to be placed, the distance between the counterbore side wall and the outer peripheral edge of the wafer to be placed can be increased, and the wafer is placed at the center of the counterbore.
  • the length between the side wall of the counterbore and the outer peripheral end of the mounted wafer can be made substantially constant over the entire circumference, and the thin film to be formed The uniformity of the film thickness in the wafer surface can be improved.
  • At least a surface in contact with the wafer is an inclined surface.
  • the surface of the projection that contacts the wafer is an inclined surface, even when the susceptor rotates during vapor phase growth or the like, even if the wafer is displaced horizontally and hits the projection, the outer peripheral edge of the wafer Since the contact area between the portion and the projection is small and the impact can be mitigated, the possibility of damaging the wafer can be reduced.
  • the diameter of the side wall of the counterbore is preferably 1.3 times or more than the diameter of the wafer to be placed.
  • the diameter of the counterbore side wall is not less than 1.3 times the diameter of the wafer to be placed, so that when the wafer is placed on the susceptor and a thin film is vapor-phase grown, the side wall of the counterbore is placed. A sufficient length between the outer peripheral end portion of the wafer and the thickness of the thin film to be formed in the wafer surface can be reliably improved.
  • a vapor phase growth apparatus including the susceptor is preferable, and a vapor phase growth method of a wafer in which a thin film is vapor-phase grown on the wafer using the susceptor is preferable.
  • a vapor phase growth method of a wafer in which a thin film is vapor-phase grown on the wafer using the susceptor is preferable.
  • the distance between the counterbore side wall and the outer peripheral edge of the wafer placed is almost constant over the entire circumference.
  • the film thickness uniformity in the wafer surface of the thin film to be formed can be improved, and the positional deviation of the wafer in the counterbore during vapor phase growth can be suppressed.
  • a wafer having a thin film with high yield and high film thickness uniformity can be manufactured.
  • FIG. 1 is a schematic view showing a first embodiment of a susceptor according to the present invention. It is the schematic which shows 2nd Embodiment of the susceptor which concerns on this invention. It is the figure which expanded the part of A of FIG. It is a figure which shows the outline of the conventional 1 sheet holding
  • the film thickness distribution on the outer periphery of the wafer varies. Even if the flow of the source gas to be supplied is controlled, it has been extremely difficult to form a thin film so as to be uniform within the wafer surface. In particular, the film thickness at the orientation flat portion of the wafer is increased, resulting in a problem that the manufacturing yield of semiconductor devices is deteriorated. In addition, even when the wafer is placed on the susceptor and shifted from the center of the counterbore and is vapor-phase grown as it is, there is a problem that the film thickness distribution on the outer periphery of the wafer is not good.
  • the present inventor has intensively studied to improve the variation in the film thickness distribution of the thin film to be vapor-phase grown on the wafer.
  • the wafer is conventionally mounted on a counterbore having the same size as the wafer diameter.
  • the wafer does not fit perfectly into the counterbore and has some margin. Therefore, the wafer position is deviated in the side wall of the counterbore, which is the positioning means, due to various causes such as a shift of the wafer mounting position and slippage of the wafer due to the horizontal tilt of the susceptor. Is not a good fit. Therefore, the present inventor conducted verification by paying attention to the distance between the side wall of the counterbore as positioning means and the outer peripheral edge of the wafer. As a result, it has been found that when the distance between the outer peripheral edge of the wafer and the counterbore side wall is short, the film thickness of the epitaxial layer grown as a thin film is thin, and conversely, it is thick when it is far.
  • the present inventor conducted further research to suppress the variation in the film thickness distribution of the vapor-deposited thin film and improve the uniformity even if the wafer has an orientation flat portion or the wafer is slightly biased in the counterbore.
  • the size of the counterbore to be formed is larger than that of conventional wafers, resulting in variations in the distance distribution between the peripheral edge of the wafer including the orientation flat and the side wall of the counterbore. As a result, the present invention has been completed.
  • FIG. 1 is a schematic view showing a first embodiment of a susceptor according to the present invention
  • FIG. 3 is an enlarged view of a portion A in FIG.
  • the susceptor 10 of the first embodiment has a disk shape, and one counterbore 1 is formed in a circular concave shape.
  • the counterbore 1 has a bottom surface 1b and a side wall 1a, and a portion raised from the bottom surface 1b of the counterbore is an outer peripheral portion 2 of the susceptor.
  • the diameter of the side wall 1a of the counterbore is larger than the diameter of the wafer W to be mounted.
  • the wafer W is mounted on the center part of the counterbore 1 on the bottom surface 1b of the counterbore.
  • Eight protrusions 1c protrude at equal intervals. This protrusion is formed at a position circumscribing the circumference having the length of the diameter of the wafer to be placed.
  • the distance between the outer peripheral edge of the wafer and the counterbore side wall can be increased by making the diameter of the counterbore side wall significantly larger than the diameter of the wafer to be placed.
  • the distance between the orientation flat portion of the wafer W and the counterbore side wall, the distance between the wafer outer peripheral end other than the orientation flat portion of the wafer W and the counterbore side wall, and the difference between these two distances can be reduced. Therefore, variations based on the distance distribution from the counterbore side wall are suppressed over the entire circumference of the wafer. Therefore, variation in the film thickness distribution of the epitaxial layer formed as a thin film including the orientation flat portion can be suppressed, and uniformity in the plane of the thin film can be improved. This effect leads to improvement in quality, improvement in operating rate, and improvement in productivity when an epitaxial wafer is manufactured by vapor-phase growth of an epitaxial layer on a wafer, for example.
  • the side wall of the counterbore has played the role of the wafer drop-off prevention function and the positioning function, but in the present invention, these functions are not used together, and the wafer positioning function is provided with a protrusion on the bottom surface of the counterbore. As a result, the distance between the side wall of the counterbore and the outer peripheral edge of the wafer could be increased.
  • the counterbore side wall in the present invention has a function of preventing the wafer from falling off.
  • connects the wafer W is an inclined surface like FIG.
  • the shape of the protrusion 1c is not particularly limited. For example, as shown in FIG.
  • the shape of the protrusion 1c is a truncated cone shape, it can be easily formed on the susceptor, and the contact surface with the wafer can be an inclined surface. . In addition, it may be conical or hemispherical.
  • the number of protrusions is not particularly limited, but is preferably 3 or more in order to position the wafer.
  • the diameter of the side wall of the counterbore is preferably 1.3 times or more of the diameter of the wafer to be placed.
  • the outer peripheral edge of the wafer and the side wall of the counterbore when the wafer is placed so that the center of the wafer matches the center of the counterbore Is preferably 26.2 to 30.5 mm, for example.
  • the diameter of the counterbore side wall is not less than 1.3 times the diameter of the wafer to be placed, so that when the wafer is placed on the susceptor and a thin film is vapor-phase grown, the side wall of the counterbore is placed. A sufficient distance from the outer peripheral edge of the wafer can be secured, and the film thickness uniformity in the wafer surface of the thin film to be formed can be improved more reliably.
  • FIG. 2 is a schematic view showing a second embodiment of the susceptor according to the present invention.
  • the same elements as those in the first embodiment are denoted by the same instruction numbers as in FIG.
  • the susceptor 20 of the second embodiment is also disk-shaped, and four counterbore 1 is formed in a circular concave shape.
  • the four counterbore 1 has a bottom surface 1b and a side wall 1a, and the part of the counterbore raised from the bottom surface 1b of the counterbore is the outer peripheral portion 2 of the susceptor.
  • the diameter of the side wall 1a of the counterbore is larger than the diameter of the wafer W to be mounted.
  • the wafer W is mounted on the center part of the counterbore 1 on the bottom surface 1b of the counterbore.
  • Eight protrusions 1c protrude at equal intervals. The protrusions are formed at positions circumscribing the circumference having the length of the diameter of the wafer to be placed.
  • the present invention can also be applied to a susceptor when holding a plurality of wafers.
  • the susceptor holds a plurality of wafers as in the second embodiment, the number of wafers to be processed at a time can be increased, so that the manufacturing efficiency can be improved and the film thickness is uniform. High-quality, high-quality wafers can be manufactured in a short time.
  • the susceptor according to the present invention as in the first and second embodiments is preferably used in a vapor phase growth apparatus or a vapor phase growth method of a wafer in which a thin film is vapor-phase grown on a wafer.
  • a wafer having a thin film with good film thickness uniformity can be manufactured.
  • Example 1 A susceptor according to the present invention shown in FIG. 1 was prepared.
  • the susceptor 10 is a susceptor in which one concave counterbore is formed.
  • the diameter of the counterbore side wall is 204 mm, and the width of the outer peripheral portion 2 of the susceptor is 10.4 mm.
  • eight protrusions 1c shown in FIG. 6 were provided on a circumference of 152.5 mm at equal intervals of 45 degrees.
  • the size of one protrusion 1c is a frustoconical shape with a height of 0.58 mm and a flat apex, the diameter of the upper base is 2.0 mm, and the angle formed by the side surfaces is 60 degrees.
  • the base material of the susceptor is graphite, and the entire surface thereof is coated with a SiC film by a CVD method.
  • an epitaxial layer was formed to a thickness of 10 ⁇ m on five sample wafers (diameter 150 mm) having an orientation flat portion.
  • the wafer to be processed and the conditions for forming the epitaxial layer were the same for all the sample wafers, and only the mounting position in the counterbore was changed. A specific example is shown in FIG.
  • FIG. 7 is a diagram for explaining the mounting positions of the wafers in Examples and Comparative Examples.
  • the wafer was placed so that the center of the counterbore and the center of the wafer W substantially coincided (see FIG. 7A).
  • the protrusion 1c which is a wafer positioning means, was placed so that the outer peripheral portion opposite to the orientation flat portion of the wafer was in contact (see FIG. 7B).
  • the film thickness of the epitaxial layer produced by this was measured.
  • the measurement part of the film thickness was measured at 5 points shown in FIG. 7A in each sample wafer. These five points are an orientation flat vicinity O, a central vicinity C, an end E of the wafer opposite to the orientation flat part, an intermediate point R1 between O and C, and an intermediate point R2 between C and E.
  • Table 1 The results are shown in Table 1 below.
  • the susceptor 40 is a susceptor in which one concave counterbore 41 is formed.
  • the diameter of the counterbore side wall is 152.5 mm, and the width of the outer peripheral portion 42 of the susceptor is 36.2 mm.
  • the base material of the susceptor is graphite, and the entire surface thereof is coated with a SiC film by a CVD method.
  • an epitaxial layer was formed to a thickness of 10 ⁇ m on five sample wafers having an orientation flat portion.
  • the wafer to be processed and the conditions for forming the epitaxial layer were the same for the example and all sample wafers, and only the placement position in the counterbore was changed. A specific example is shown in FIG.
  • Comparative Examples 1 to 5 it was placed so that the center of the counterbore and the center of the wafer W substantially coincided (see FIG. 7C).
  • Comparative Examples 6 to 10 the wafer was placed so that the outer peripheral portion opposite to the orientation flat portion of the wafer was in contact with the side wall of the counterbore as the wafer positioning means (see FIG. 7D).
  • the film thickness of the epitaxial layer produced by this was measured.
  • the measurement part of the film thickness was measured at the same five points as shown in FIG. These five points are an orientation flat vicinity O, a central vicinity C, an end E of the wafer opposite to the orientation flat part, an intermediate point R1 between O and C, and an intermediate point R2 between C and E.
  • Table 1 Table 1 below.
  • “%” is defined as (maximum film thickness ⁇ minimum film thickness) / (maximum film thickness + minimum film thickness) ⁇ 100 (%).
  • the present invention is not limited to the above embodiment.
  • the above-described embodiment is an exemplification, and the present invention has any configuration substantially the same as the technical idea described in the claims of the present invention and exhibits the same function and effect. It is included in the technical scope.

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Abstract

A susceptor (10) having a counterbore (1) for mounting a wafer (W) horizontally in a vapor phase growth system, in which the counterbore (1) is a circular recess having a bottom surface (1b) and a sidewall (1a). The sidewall (1a) of the counterbore has a diameter larger than that of the wafer (W) to be mounted, and a plurality of protrusions (1c) are formed on the bottom surface (1b) of the counterbore so that the wafer is mounted in the central portion of the counterbore. When a thin film is grown in a vapor phase on the wafer by using a vapor phase growth system, thickness uniformity of the thin film can be improved in the in-plane direction of the wafer.

Description

サセプタ及び気相成長装置並びに気相成長方法Susceptor, vapor phase growth apparatus, and vapor phase growth method
　本発明は、ウェーハに薄膜を気相成長させるときに使用する気相成長装置内で、ウェーハを水平に載置するサセプタに関し、さらに、それを利用した気相成長装置、並びに気相成長方法に関する。
　 The present invention relates to a susceptor for horizontally placing a wafer in a vapor phase growth apparatus used for vapor phase growth of a thin film on a wafer, and further relates to a vapor phase growth apparatus and a vapor phase growth method using the same. .
　半導体デバイスの製造工程においては、容器で外界と遮断した半導体基板（以下、単にウェーハと呼ぶこともある）上に反応性ガスを供給し、半導体基板上に薄膜を形成する工程がある。これらの工程では原料ガスの供給により、半導体基板上で気相反応を起して薄膜を形成する気相成長装置が使用されている。 In the manufacturing process of a semiconductor device, there is a process of forming a thin film on a semiconductor substrate by supplying a reactive gas onto a semiconductor substrate (hereinafter also simply referred to as a wafer) that is blocked from the outside by a container. In these steps, a vapor phase growth apparatus is used that forms a thin film by causing a gas phase reaction on a semiconductor substrate by supplying a raw material gas.
　それらの中でも特に、シリコン基板上にシリコンの単結晶を成長させるエピタキシャル層成長装置はＬＳＩ（Ｌａｒｇｅ　Ｓｃａｌｅ　Ｉｎｔｅｇｒａｔｅｄ　Ｃｉｒｃｕｉｔ）等の半導体デバイスの製造工程で利用されている。この装置ではシリコン基板を通常１０００℃以上に加熱し、反応容器内に四塩化珪素、トリクロルシラン等の原料ガスと水素との混合ガスを供給し、水素還元または熱分解することによって、シリコン基板上にエピタキシャル成長による単結晶のシリコン薄膜を成長させる。また、エピタキシャル成長は半導体デバイスの製造工程においてバイポーラ素子の耐圧などを高めるために用いられており、素子においてもメガビットのメモリを製作する場合、α線によるソフトエラーやラッチアップを防ぐために必要な技術になっている。 Among them, in particular, an epitaxial layer growth apparatus for growing a single crystal of silicon on a silicon substrate is used in a manufacturing process of a semiconductor device such as an LSI (Large Scale Integrated Circuit). In this apparatus, a silicon substrate is usually heated to 1000 ° C. or more, a mixed gas of a raw material gas such as silicon tetrachloride and trichlorosilane and hydrogen is supplied into a reaction vessel, and hydrogen reduction or thermal decomposition is performed on the silicon substrate. A single crystal silicon thin film is grown by epitaxial growth. Epitaxial growth is used to increase the breakdown voltage of bipolar devices in the manufacturing process of semiconductor devices. When manufacturing megabit memories in devices, it is a necessary technology to prevent soft errors and latch-up caused by alpha rays. It has become.
　このようなエピタキシャル成長には、例えば図５に示すような気相成長装置が用いられている。
　図５は従来の気相成長装置を示す概略図である。図中５０は気相成長装置を示しており、気相成長装置５０は石英製のチャンバ５１とチャンバベース５２とによって外界と隔離されている。チャンバ５１内の中央部には円盤状のサセプタ５６を支持する支持台５３が回転可能に配設され、使用時にはこのサセプタ５６に複数個の半導体基板５５を成長面を上にして水平に載置し、気相成長がなされる。
　また、支持台５３の中央部は原料ガス導入部５７となっており、支持台５３の下部はチャンバベース５２の下方へ突出している。また、サセプタ５６の中央にある開口部５６ａに薄膜を形成するための原料を含むガスを供給するための原料ガスノズル５８が接続されている。この原料ガスノズル５８には原料ガスが半導体基板５５の上面に対して略平行に流出するように複数個の孔５８ａが形成されている。一方、チャンバベース５２の中央部付近すなわち支持台５３の周囲には原料ガスの排出口５９が形成されている。また、半導体基板を加熱するため、誘導加熱コイル５４がサセプタ５６の下方に渦状に設置されている。 For such epitaxial growth, for example, a vapor phase growth apparatus as shown in FIG. 5 is used.
FIG. 5 is a schematic view showing a conventional vapor phase growth apparatus. In the figure, reference numeral 50 denotes a vapor phase growth apparatus. The vapor phase growth apparatus 50 is isolated from the outside by a quartz chamber 51 and a chamber base 52. A support base 53 that supports a disc-shaped susceptor 56 is rotatably disposed in the center of the chamber 51, and in use, a plurality of semiconductor substrates 55 are placed horizontally on the susceptor 56 with the growth surface up. Then, vapor phase growth is performed.
Further, the central portion of the support base 53 is a source gas introduction portion 57, and the lower portion of the support base 53 protrudes below the chamber base 52. A source gas nozzle 58 for supplying a gas containing a source material for forming a thin film is connected to an opening 56a in the center of the susceptor 56. The source gas nozzle 58 has a plurality of holes 58 a so that the source gas flows out substantially parallel to the upper surface of the semiconductor substrate 55. On the other hand, a source gas discharge port 59 is formed near the center of the chamber base 52, that is, around the support base 53. In addition, an induction heating coil 54 is installed in a spiral shape below the susceptor 56 in order to heat the semiconductor substrate.
　このような複数個の半導体基板を同時に処理するタイプの気相成長装置（例えば特開平６－３１０４４２号公報参照）の他に、例えば特開２００４－３１９６２３号公報のような半導体基板を１枚ずつ処理するタイプの気相成長装置がある。
　これらの一般的な気相成長装置において半導体基板に薄膜を形成する場合、成長させる薄膜の厚さを基板面内で均一化する工夫や、いかに基板を傷つけないように処理するかといった工夫が従来からなされている。そのため、図４のようなサセプタの形状を変形させることによりこのような問題を解決しようとしている。 In addition to such a type of vapor phase growth apparatus that simultaneously processes a plurality of semiconductor substrates (see, for example, Japanese Patent Laid-Open No. 6-310442), for example, semiconductor substrates as in Japanese Patent Laid-Open No. 2004-319623 are provided one by one. There is a type of vapor deposition apparatus to be processed.
In the case of forming a thin film on a semiconductor substrate in these general vapor phase growth apparatuses, there have been conventionally devised techniques for uniformizing the thickness of the thin film to be grown within the substrate surface and how to process the substrate so as not to damage it. It is made from. Therefore, such a problem is attempted to be solved by deforming the shape of the susceptor as shown in FIG.
　図４は、従来の１枚保持タイプのサセプタの概略を示す図である。この従来のサセプタ４０は、例えば黒鉛基材上にＣＶＤ法により厚さ１５０μｍ程度のＳｉＣ膜をコーティングした円盤形状であり、その中央部にはウェーハＷの直径とほぼ同じ大きさの直径を有する円形凹形状のザグリ４１が形成されたものである。ザグリ４１の外側は一段高くなっており、気相成長中にウェーハＷが回転するサセプタ４０から水平方向にズレて外れるのを防止する。すなわち、ザグリの側壁の部分がウェーハのサセプタ内の位置決め手段となっている。そのため、ザグリの底面より一段高くなった部分を便宜上ザグリガイド４２と呼んでいる。 FIG. 4 is a view showing an outline of a conventional single-sheet holding type susceptor. The conventional susceptor 40 has a disk shape in which, for example, a graphite substrate is coated with a SiC film having a thickness of about 150 μm by a CVD method, and a circular portion having a diameter approximately the same as the diameter of the wafer W at the center thereof. A concave counterbore 41 is formed. The outside of the counterbore 41 is raised one step higher to prevent the wafer W from being displaced in the horizontal direction from the rotating susceptor 40 during vapor phase growth. That is, the portion of the counterbore side wall is a positioning means in the susceptor of the wafer. Therefore, a portion that is one step higher than the bottom surface of the counterbore is called a counterbore guide 42 for convenience.
　特開２００４－３１９６２３号公報のサセプタは、図４のようにウェーハを１枚保持するタイプであるが、ザグリの底面の外周には、図４に図示されていない傾斜面が形成されている。そして、この傾斜面でウェーハ外周端部を保持することによりウェーハに傷がつかないようにしている。 The susceptor of Japanese Patent Application Laid-Open No. 2004-319623 is a type that holds one wafer as shown in FIG. 4, but an inclined surface not shown in FIG. 4 is formed on the outer periphery of the counterbore. The wafer outer peripheral end is held by this inclined surface so that the wafer is not damaged.
　一方、特開平６－３１０４４２号公報におけるサセプタのザグリの形状は底面が平たく、ザグリの底面から１段上がったザグリガイドには、外周部を囲む断面形状は矩形の凸部が形成されている。このザグリガイド上の凸部により原料ガスの流れを整流して、ウェーハに気相成長させる薄膜の膜厚の均一性を図っている。
　しかしこのような工夫がなされたサセプタを薄膜形成時に用いても、ウェーハ面内での膜厚にはバラツキがあり、より一層均一になるように薄膜を形成することは難しかった。
　 On the other hand, the shape of the counterbore of the susceptor in Japanese Patent Application Laid-Open No. 6-310442 has a flat bottom surface, and the counterbore guide that is raised by one step from the bottom surface of the counterbore has a convex portion having a rectangular cross section surrounding the outer periphery. The flow of the raw material gas is rectified by the convex portions on the counterbored guide, and the film thickness of the thin film to be vapor-phase grown on the wafer is made uniform.
However, even if a susceptor with such a device is used for forming a thin film, the film thickness varies within the wafer surface, and it is difficult to form a thin film so as to be even more uniform.
　本発明は、このような問題点に鑑みてなされたもので、気相成長装置を使用してウェーハに薄膜を気相成長させる際、形成する薄膜のウェーハ面内における膜厚の均一性を改善することができるサセプタを提供し、さらには、このサセプタを利用した気相成長装置及びウェーハの気相成長方法を提供することを目的とする。 The present invention has been made in view of such problems. When a thin film is vapor-phase grown on a wafer using a vapor phase growth apparatus, the uniformity of the film thickness in the wafer surface of the thin film to be formed is improved. It is another object of the present invention to provide a susceptor that can be used, and to provide a vapor phase growth apparatus and a wafer vapor phase growth method using the susceptor.
　上記目的を達成するため、本発明は、気相成長装置内でウェーハを水平に載置するザグリが形成されたサセプタにおいて、
　前記ザグリは、底面と側壁を有する円形の凹形状であり、
　前記ザグリの側壁の直径は、前記載置するウェーハの直径より大きく、
　前記ザグリの底面には、前記ウェーハがザグリの中央部に載置されるように該ザグリの底面から突出する複数の突起物が形成されたものであることを特徴とするサセプタを提供する。 To achieve the above object, the present invention provides a susceptor in which a counterbore for horizontally placing a wafer in a vapor phase growth apparatus is formed.
The counterbore is a circular concave shape having a bottom surface and a side wall,
The diameter of the counterbore side wall is larger than the diameter of the wafer to be placed,
A susceptor is provided, wherein a plurality of protrusions are formed on a bottom surface of the counterbore so as to protrude from the bottom surface of the counterbore so that the wafer is placed in a central portion of the counterbore.
　このように本発明のサセプタは、ザグリの側壁の直径が載置するウェーハの直径より大きく、ザグリの底面には、ウェーハがザグリの中央部に載置されるように該ザグリの底面から突出する複数の突起物が形成されたものである。ザグリの側壁の直径が載置するウェーハの直径より大きいため、ザグリの側壁と載置するウェーハの外周端部の距離を長くすることができ、かつ、ウェーハがザグリの中央部に載置されるように該ザグリの底面から突出する複数の突起物が形成されているため、処理中のウェーハのザグリ内での位置ズレを抑制することができる。これにより、ウェーハに薄膜を気相成長させる時に、ザグリの側壁と載置されたウェーハの外周端部との間の長さを全周に渡ってほぼ一定とすることができ、形成する薄膜のウェーハ面内における膜厚の均一性を向上することができる。 Thus, in the susceptor of the present invention, the diameter of the side wall of the counterbore is larger than the diameter of the wafer to be mounted, and the bottom surface of the counterbore protrudes from the bottom surface of the counterbore so that the wafer is mounted at the center portion of the counterbore. A plurality of protrusions are formed. Since the diameter of the counterbore side wall is larger than the diameter of the wafer to be placed, the distance between the counterbore side wall and the outer peripheral edge of the wafer to be placed can be increased, and the wafer is placed at the center of the counterbore. As described above, since a plurality of protrusions protruding from the bottom surface of the counterbore are formed, it is possible to suppress positional deviation of the wafer being processed in the counterbore. As a result, when vapor-depositing a thin film on the wafer, the length between the side wall of the counterbore and the outer peripheral end of the mounted wafer can be made substantially constant over the entire circumference, and the thin film to be formed The uniformity of the film thickness in the wafer surface can be improved.
　この場合、前記突起物は、少なくともウェーハに接する面が傾斜面であることが好ましい。
　このように、突起物の少なくともウェーハに接する面が傾斜面であることにより、気相成長中にサセプタが回転したとき等、ウェーハが水平方向にズレて突起物にぶつかっても、ウェーハの外周端部と突起物の接触面積が小さく、且つその衝撃も緩和できるため、ウェーハを傷つける可能性を低くすることができる。 In this case, it is preferable that at least a surface in contact with the wafer is an inclined surface.
As described above, since at least the surface of the projection that contacts the wafer is an inclined surface, even when the susceptor rotates during vapor phase growth or the like, even if the wafer is displaced horizontally and hits the projection, the outer peripheral edge of the wafer Since the contact area between the portion and the projection is small and the impact can be mitigated, the possibility of damaging the wafer can be reduced.
　さらに、前記ザグリの側壁の直径は、前記載置するウェーハの直径の１．３倍以上であることが好ましい。
　このように、ザグリの側壁の直径は、載置するウェーハの直径の１．３倍以上であることにより、サセプタにウェーハを載置して薄膜を気相成長させる時に、ザグリの側壁と載置されたウェーハの外周端部との間の長さを十分にとることができ、形成する薄膜のウェーハ面内における膜厚の均一性を確実に向上することができる。 Further, the diameter of the side wall of the counterbore is preferably 1.3 times or more than the diameter of the wafer to be placed.
Thus, the diameter of the counterbore side wall is not less than 1.3 times the diameter of the wafer to be placed, so that when the wafer is placed on the susceptor and a thin film is vapor-phase grown, the side wall of the counterbore is placed. A sufficient length between the outer peripheral end portion of the wafer and the thickness of the thin film to be formed in the wafer surface can be reliably improved.
　また、上記サセプタを具備する気相成長装置が好ましく、さらには、上記サセプタを使用してウェーハに薄膜を気相成長させるウェーハの気相成長方法が好ましい。
　このように、上記サセプタを気相成長装置やウェーハに薄膜を気相成長させるウェーハの気相成長方法で使用することにより、歩留まり良く膜厚均一性の高い薄膜を有するウェーハを製造することができる。 Further, a vapor phase growth apparatus including the susceptor is preferable, and a vapor phase growth method of a wafer in which a thin film is vapor-phase grown on the wafer using the susceptor is preferable.
As described above, by using the susceptor in a vapor phase growth apparatus or a wafer vapor phase growth method for vapor-depositing a thin film on a wafer, a wafer having a thin film with high yield and high film thickness uniformity can be manufactured. .
　本発明の気相成長装置用のサセプタであれば、ウェーハに薄膜を気相成長させる時に、ザグリの側壁と載置されたウェーハの外周端部との間の距離を全周に渡ってほぼ一定とすることができ、形成する薄膜のウェーハ面内における膜厚の均一性を向上することができ、且つ、気相成長中のウェーハのザグリ内での位置ズレを抑制することができる。また、このようなサセプタを使用した本発明の気相成長装置及び気相成長方法であれば、歩留まり良く膜厚均一性の高い薄膜を有するウェーハを製造することができる。
　 With the susceptor for the vapor phase growth apparatus of the present invention, when vapor-depositing a thin film on a wafer, the distance between the counterbore side wall and the outer peripheral edge of the wafer placed is almost constant over the entire circumference. The film thickness uniformity in the wafer surface of the thin film to be formed can be improved, and the positional deviation of the wafer in the counterbore during vapor phase growth can be suppressed. Further, with the vapor phase growth apparatus and vapor phase growth method of the present invention using such a susceptor, a wafer having a thin film with high yield and high film thickness uniformity can be manufactured.
本発明に係るサセプタの第１実施形態を示す概略図である。1 is a schematic view showing a first embodiment of a susceptor according to the present invention. 本発明に係るサセプタの第２実施形態を示す概略図である。It is the schematic which shows 2nd Embodiment of the susceptor which concerns on this invention. 図１のＡの部分を拡大した図である。It is the figure which expanded the part of A of FIG. 従来の１枚保持タイプのサセプタの概略を示す図である。It is a figure which shows the outline of the conventional 1 sheet holding | maintenance type susceptor. 従来の気相成長装置を示す概略図である。It is the schematic which shows the conventional vapor phase growth apparatus. 本発明の突起物の一例を示す図である。It is a figure which shows an example of the protrusion of this invention. 実施例、比較例のウェーハの載置位置を説明するための図であり、（ａ）は実施例１～５、（ｂ）は実施例６～１０、（ｃ）は比較例１～５、（ｄ）は比較例６～１０を示す図である。It is a figure for demonstrating the mounting position of the wafer of an Example and a comparative example, (a) is Examples 1-5, (b) is Examples 6-10, (c) is Comparative Examples 1-5, (D) is a view showing Comparative Examples 6 to 10. FIG.
　前述したように、従来の図４に示すようなサセプタでは、どんなにザグリの中心と載置するウェーハの中心を合わせて気相成長させても、ウェーハの外周部における薄膜の膜厚分布にバラツキがあり、供給する原料ガスの流れ等を制御しても、ウェーハ面内で均一になるように薄膜を形成することは困難を極めていた。
　特にウェーハのオリフラ部分での膜厚が厚くなって、半導体デバイスの製造歩留まりが悪化するという問題があった。また、ウェーハをサセプタに載置する時にザグリの中心からズレて、そのまま気相成長した場合も、ウェーハ外周部における膜厚分布がよくないという問題があった。 As described above, in the conventional susceptor shown in FIG. 4, no matter how the center of the counterbore and the center of the wafer to be placed are vapor-phase grown, the film thickness distribution on the outer periphery of the wafer varies. Even if the flow of the source gas to be supplied is controlled, it has been extremely difficult to form a thin film so as to be uniform within the wafer surface.
In particular, the film thickness at the orientation flat portion of the wafer is increased, resulting in a problem that the manufacturing yield of semiconductor devices is deteriorated. In addition, even when the wafer is placed on the susceptor and shifted from the center of the counterbore and is vapor-phase grown as it is, there is a problem that the film thickness distribution on the outer periphery of the wafer is not good.
　そこで、本発明者は、このウェーハに気相成長させる薄膜の膜厚分布のバラツキを改善すべく鋭意研究を行った。
　図４のように、従来はウェーハ直径とほぼ同じ大きさのザグリにウェーハを載置している。しかし、ウェーハはザグリにぴったりはまるわけではなく、多少の余裕がある。従って、ウェーハの載置位置のズレや、サセプタの水平方向の傾きによるウェーハのすべり、等様々な原因により結果的に位置決め手段であるザグリの側壁内でウェーハの位置は偏り、ザグリとウェーハの中心がぴったり合うことは少ない。そこで、本発明者は、位置決め手段であるザグリの側壁とウェーハ外周端部との距離に注目し、検証を行った。その結果、ウェーハ外周端部とザグリ側壁との距離が近いと薄膜として気相成長させたエピタキシャル層の膜厚は薄くなり、逆に遠いと厚くなることを発見した。 Therefore, the present inventor has intensively studied to improve the variation in the film thickness distribution of the thin film to be vapor-phase grown on the wafer.
As shown in FIG. 4, the wafer is conventionally mounted on a counterbore having the same size as the wafer diameter. However, the wafer does not fit perfectly into the counterbore and has some margin. Therefore, the wafer position is deviated in the side wall of the counterbore, which is the positioning means, due to various causes such as a shift of the wafer mounting position and slippage of the wafer due to the horizontal tilt of the susceptor. Is not a good fit. Therefore, the present inventor conducted verification by paying attention to the distance between the side wall of the counterbore as positioning means and the outer peripheral edge of the wafer. As a result, it has been found that when the distance between the outer peripheral edge of the wafer and the counterbore side wall is short, the film thickness of the epitaxial layer grown as a thin film is thin, and conversely, it is thick when it is far.
　この検証結果より、ザグリとウェーハの中心が合っていたとしても、オリフラ部分は常にもっともザグリの側壁から遠く、この部分の薄膜の膜厚が厚くなることも説明できる。そこで本発明者は、さらに研究を重ね、オリフラ部が形成されたウェーハや、ザグリ内で多少ウェーハが偏っても、気相成長させた薄膜の膜厚分布のバラツキを抑制し、均一性を高めるには、形成するザグリの大きさを従来のウェーハにあわせた大きさのものよりも大きくすることで、オリフラ部を含めたウェーハの外周端部と、ザグリの側壁との間の距離分布のバラツキを全周にわたって抑制すればよいことに想到し、本発明を完成させた。 From this verification result, it can be explained that even if the center of the counterbore and the wafer are aligned, the orientation flat part is always farthest from the side wall of the counterbore, and the film thickness of this part becomes thicker. Therefore, the present inventor conducted further research to suppress the variation in the film thickness distribution of the vapor-deposited thin film and improve the uniformity even if the wafer has an orientation flat portion or the wafer is slightly biased in the counterbore. The size of the counterbore to be formed is larger than that of conventional wafers, resulting in variations in the distance distribution between the peripheral edge of the wafer including the orientation flat and the side wall of the counterbore. As a result, the present invention has been completed.
　以下、本発明の実施形態を、図面を参照しながら説明するが、本発明はこれに限定されるものではない。
　まず、本発明の第１実施形態として、１枚ずつウェーハに処理を施す気相成長装置内で使用されるサセプタについて説明する。図１は、本発明に係るサセプタの第１実施形態を示す概略図であり、図３は、図１のＡの部分を拡大した図である。 Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto.
First, as a first embodiment of the present invention, a susceptor used in a vapor phase growth apparatus that processes wafers one by one will be described. FIG. 1 is a schematic view showing a first embodiment of a susceptor according to the present invention, and FIG. 3 is an enlarged view of a portion A in FIG.
　第１実施形態のサセプタ１０は円板形状であり、１つのザグリ１が円形の凹形状に形成されたものである。このザグリ１は底面１ｂと側壁１ａを有し、ザグリの底面１ｂより一段上がった部分は、サセプタの外周部２である。ザグリの側壁１ａの直径は、載置するウェーハＷの直径より大きく、ザグリの底面１ｂには、ウェーハＷがザグリ１の中央部に載置されるように、位置決め手段として、ザグリの底面１ｂから８つの突起物１ｃが等間隔に突出している。この突起物は、載置するウェーハの直径の長さを持つ円周に外接する位置に形成されている。 The susceptor 10 of the first embodiment has a disk shape, and one counterbore 1 is formed in a circular concave shape. The counterbore 1 has a bottom surface 1b and a side wall 1a, and a portion raised from the bottom surface 1b of the counterbore is an outer peripheral portion 2 of the susceptor. The diameter of the side wall 1a of the counterbore is larger than the diameter of the wafer W to be mounted. From the bottom surface 1b of the counterbore, as a positioning means, the wafer W is mounted on the center part of the counterbore 1 on the bottom surface 1b of the counterbore. Eight protrusions 1c protrude at equal intervals. This protrusion is formed at a position circumscribing the circumference having the length of the diameter of the wafer to be placed.
　このように、載置するウェーハの直径よりザグリの側壁の直径を大幅に大きくすることで、ウェーハの外周端部とザグリ側壁の距離を大きくすることができる。これにより、ウェーハＷのオリフラ部とザグリ側壁との距離、ウェーハＷのオリフラ部以外のウェーハ外周端部とザグリ側壁との距離、この２つの距離の差を少なくすることができる。そのため、ウェーハの全周にわたって、ザグリ側壁からの距離分布に基づくバラツキが抑制される。従って、オリフラ部も含めて薄膜として形成するエピタキシャル層の膜厚分布のバラツキを抑制することができ、薄膜の面内での均一性を向上させることができる。この効果は、例えばウェーハにエピタキシャル層を気相成長させて、エピタキシャルウェーハを製造する際、品質の向上、稼働率の向上、及び生産性の向上にもつながる。 Thus, the distance between the outer peripheral edge of the wafer and the counterbore side wall can be increased by making the diameter of the counterbore side wall significantly larger than the diameter of the wafer to be placed. Thereby, the distance between the orientation flat portion of the wafer W and the counterbore side wall, the distance between the wafer outer peripheral end other than the orientation flat portion of the wafer W and the counterbore side wall, and the difference between these two distances can be reduced. Therefore, variations based on the distance distribution from the counterbore side wall are suppressed over the entire circumference of the wafer. Therefore, variation in the film thickness distribution of the epitaxial layer formed as a thin film including the orientation flat portion can be suppressed, and uniformity in the plane of the thin film can be improved. This effect leads to improvement in quality, improvement in operating rate, and improvement in productivity when an epitaxial wafer is manufactured by vapor-phase growth of an epitaxial layer on a wafer, for example.
　従来では、ザグリの側壁がウェーハの脱落防止機能と、位置決め機能の役割を果たしていたが、本発明では、これらの機能を併用せず、ウェーハの位置決め機能は、別途ザグリの底面に突起物を設けることにより、ザグリの側壁とウェーハ外周端部との距離を離すことができた。一方、本発明におけるザグリの側壁は、ウェーハの脱落防止機能を有する。 Conventionally, the side wall of the counterbore has played the role of the wafer drop-off prevention function and the positioning function, but in the present invention, these functions are not used together, and the wafer positioning function is provided with a protrusion on the bottom surface of the counterbore. As a result, the distance between the side wall of the counterbore and the outer peripheral edge of the wafer could be increased. On the other hand, the counterbore side wall in the present invention has a function of preventing the wafer from falling off.
　そして、突起物１ｃは、図６のように、少なくともウェーハＷに接する面が傾斜面であることが好ましい。このように、突起物の少なくともウェーハに接する面が傾斜面であることにより、気相成長中にサセプタが回転したとき等、ウェーハが水平方向にズレて突起物に接触しても、ウェーハの外周端部と突起物の接触面積が小さく、且つその衝撃も緩和できるため、ウェーハを傷つける可能性を低くすることができる。
　この突起物１ｃの形状は、特に限定されないが、例えば図６のように、円錐台の形状であると、サセプタに簡単に作成でき、且つ、ウェーハとの接触面を傾斜面とすることができる。他にも、円錐形状、半球形状であってもよい。突起物の数は特に限定されないが、ウェーハの位置決めをする必要上、３個以上が好ましい。 And as for the protrusion 1c, it is preferable that the surface which contact | connects the wafer W is an inclined surface like FIG. As described above, since at least the surface of the projection that contacts the wafer is an inclined surface, even when the susceptor rotates during vapor phase growth, even if the wafer is displaced horizontally and contacts the projection, the outer periphery of the wafer Since the contact area between the end and the projection is small and the impact can be reduced, the possibility of damaging the wafer can be reduced.
The shape of the protrusion 1c is not particularly limited. For example, as shown in FIG. 6, if the shape of the protrusion 1c is a truncated cone shape, it can be easily formed on the susceptor, and the contact surface with the wafer can be an inclined surface. . In addition, it may be conical or hemispherical. The number of protrusions is not particularly limited, but is preferably 3 or more in order to position the wafer.
　また、ザグリの側壁の直径は、載置するウェーハの直径の１．３倍以上であることが好ましい。例えば、約１５０ｍｍ（６インチ）の直径を有するシリコンウェーハにエピタキシャル層を形成する場合、ウェーハの中心をザグリの中心に合うようにウェーハを載置したときの、ウェーハ外周端部と、ザグリの側壁との間の距離は、例えば２６．２～３０．５ｍｍであることが好ましい。このように、ザグリの側壁の直径は、載置するウェーハの直径の１．３倍以上であることにより、サセプタにウェーハを載置して薄膜を気相成長させる時に、ザグリの側壁と載置されたウェーハの外周端部との間の距離を十分にとることができ、形成する薄膜のウェーハ面内における膜厚の均一性をより確実に向上することができる。 Further, the diameter of the side wall of the counterbore is preferably 1.3 times or more of the diameter of the wafer to be placed. For example, when an epitaxial layer is formed on a silicon wafer having a diameter of about 150 mm (6 inches), the outer peripheral edge of the wafer and the side wall of the counterbore when the wafer is placed so that the center of the wafer matches the center of the counterbore Is preferably 26.2 to 30.5 mm, for example. Thus, the diameter of the counterbore side wall is not less than 1.3 times the diameter of the wafer to be placed, so that when the wafer is placed on the susceptor and a thin film is vapor-phase grown, the side wall of the counterbore is placed. A sufficient distance from the outer peripheral edge of the wafer can be secured, and the film thickness uniformity in the wafer surface of the thin film to be formed can be improved more reliably.
　次に、本発明の第２実施形態として、複数枚のウェーハを同時に処理する気相成長装置内で使用されるサセプタについて説明する。図２は、本発明に係るサセプタの第２実施形態を示す概略図である。尚、図２において、第１実施形態と同じ要素は図１と同じ指示番号を付した。 Next, as a second embodiment of the present invention, a susceptor used in a vapor phase growth apparatus for simultaneously processing a plurality of wafers will be described. FIG. 2 is a schematic view showing a second embodiment of the susceptor according to the present invention. In FIG. 2, the same elements as those in the first embodiment are denoted by the same instruction numbers as in FIG.
　第２実施形態のサセプタ２０も円板形状であり、４つのザグリ１が円形の凹形状に形成されたものである。この４つのザグリ１は底面１ｂと側壁１ａを有し、ザグリの底面１ｂより一段上がった部分は、サセプタの外周部２である。ザグリの側壁１ａの直径は、載置するウェーハＷの直径より大きく、ザグリの底面１ｂには、ウェーハＷがザグリ１の中央部に載置されるように、位置決め手段として、ザグリの底面１ｂから８つの突起物１ｃが等間隔に突出している。この突起物は、載置するウェーハの直径の長さを持つ円周に外接する位置にそれぞれ形成されている。
　このように、本発明は、複数のウェーハを保持する際のサセプタにおいても適応可能である。 The susceptor 20 of the second embodiment is also disk-shaped, and four counterbore 1 is formed in a circular concave shape. The four counterbore 1 has a bottom surface 1b and a side wall 1a, and the part of the counterbore raised from the bottom surface 1b of the counterbore is the outer peripheral portion 2 of the susceptor. The diameter of the side wall 1a of the counterbore is larger than the diameter of the wafer W to be mounted. From the bottom surface 1b of the counterbore, as a positioning means, the wafer W is mounted on the center part of the counterbore 1 on the bottom surface 1b of the counterbore. Eight protrusions 1c protrude at equal intervals. The protrusions are formed at positions circumscribing the circumference having the length of the diameter of the wafer to be placed.
Thus, the present invention can also be applied to a susceptor when holding a plurality of wafers.
　第２実施形態のように、サセプタが複数のウェーハを保持することにより、１度に処理するウェーハの枚数を増やすことができるため、製造効率を向上することができ、さらに、膜厚の均一性の高い、高品質のウェーハを短時間に多く製造することができる。 Since the susceptor holds a plurality of wafers as in the second embodiment, the number of wafers to be processed at a time can be increased, so that the manufacturing efficiency can be improved and the film thickness is uniform. High-quality, high-quality wafers can be manufactured in a short time.
　そして、上記、第１、第２の実施形態のような本発明に係るサセプタを、気相成長装置や、ウェーハに薄膜を気相成長させるウェーハの気相成長方法に利用することが好ましく、歩留まり良く膜厚均一性の高い薄膜を有するウェーハを製造することができる。
　 The susceptor according to the present invention as in the first and second embodiments is preferably used in a vapor phase growth apparatus or a vapor phase growth method of a wafer in which a thin film is vapor-phase grown on a wafer. A wafer having a thin film with good film thickness uniformity can be manufactured.
　以下に本発明の実施例を挙げて具体的に説明するが、本発明はこれらに限定されるものではない。
（実施例１～１０）
＜サセプタの仕様＞
　図１に示す本発明に係るサセプタを用意した。このサセプタ１０は、１つのサセプタに凹形状のザグリが１つ形成されたものである。また、ザグリの側壁の直径は、２０４ｍｍ、サセプタの外周部２の幅は１０．４ｍｍである。また、図６で示す突起物１ｃを１５２．５ｍｍの円周上に４５度の均等間隔で８箇所設けた。１つの突起物１ｃの大きさは、高さが０．５８ｍｍ、頂点が平らな円錐台形状で、上底の直径は２．０ｍｍ、側面のなす角度は６０度となっている。サセプタの基材は黒鉛であり、その全表面を、ＣＶＤ法によりＳｉＣ膜でコートしてある。 Examples of the present invention will be specifically described below, but the present invention is not limited thereto.
(Examples 1 to 10)
<Specifications of susceptor>
A susceptor according to the present invention shown in FIG. 1 was prepared. The susceptor 10 is a susceptor in which one concave counterbore is formed. The diameter of the counterbore side wall is 204 mm, and the width of the outer peripheral portion 2 of the susceptor is 10.4 mm. Further, eight protrusions 1c shown in FIG. 6 were provided on a circumference of 152.5 mm at equal intervals of 45 degrees. The size of one protrusion 1c is a frustoconical shape with a height of 0.58 mm and a flat apex, the diameter of the upper base is 2.0 mm, and the angle formed by the side surfaces is 60 degrees. The base material of the susceptor is graphite, and the entire surface thereof is coated with a SiC film by a CVD method.
＜エピタキシャル層の形成＞
　このようなサセプタを使用してオリフラ部を有する５枚のサンプルウェーハ（直径１５０ｍｍ）にエピタキシャル層を膜厚が１０μｍとなるように形成した。被処理物であるウェーハや、エピタキシャル層を形成する条件は全てのサンプルウェーハで同じとして、ザグリ内での載置位置のみ変化させた。その具体例を図７に示す。 <Epitaxial layer formation>
Using such a susceptor, an epitaxial layer was formed to a thickness of 10 μm on five sample wafers (diameter 150 mm) having an orientation flat portion. The wafer to be processed and the conditions for forming the epitaxial layer were the same for all the sample wafers, and only the mounting position in the counterbore was changed. A specific example is shown in FIG.
　図７は、実施例、比較例におけるウェーハの載置位置を説明するための図である。
　実施例１～５では、ザグリの中心とウェーハＷの中心とがほぼ一致するように載置した（図７（ａ）参照）。実施例６～１０では、ウェーハの位置決め手段である突起物１ｃに、ウェーハのオリフラ部とは反対側の外周部が接触するように載置した（図７（ｂ）参照）。これによって作製されたエピタキシャル層の膜厚を測定した。尚、膜厚の測定部分は、各サンプルウェーハにおいて、図７（ａ）に示す５点で測定した。この５点は、オリフラ付近Ｏ、中心付近Ｃ、オリフラ部とは反対側のウェーハの端部Ｅ、ＯとＣの中間点Ｒ１、ＣとＥの中間点Ｒ２である。この結果を下記の表１に示した。
　 FIG. 7 is a diagram for explaining the mounting positions of the wafers in Examples and Comparative Examples.
In Examples 1 to 5, the wafer was placed so that the center of the counterbore and the center of the wafer W substantially coincided (see FIG. 7A). In Examples 6 to 10, the protrusion 1c, which is a wafer positioning means, was placed so that the outer peripheral portion opposite to the orientation flat portion of the wafer was in contact (see FIG. 7B). The film thickness of the epitaxial layer produced by this was measured. In addition, the measurement part of the film thickness was measured at 5 points shown in FIG. 7A in each sample wafer. These five points are an orientation flat vicinity O, a central vicinity C, an end E of the wafer opposite to the orientation flat part, an intermediate point R1 between O and C, and an intermediate point R2 between C and E. The results are shown in Table 1 below.
（比較例１～１０）
＜サセプタの仕様＞
　図４に示す従来のサセプタを用意した。このサセプタ４０は、１つのサセプタに凹形状のザグリ４１が１つ形成されたものである。また、ザグリの側壁の直径は、１５２．５ｍｍ、サセプタの外周部４２の幅は３６．２ｍｍである。サセプタの基材は黒鉛であり、その全表面を、ＣＶＤ法によりＳｉＣ膜でコートしてある。 (Comparative Examples 1 to 10)
<Specifications of susceptor>
A conventional susceptor shown in FIG. 4 was prepared. The susceptor 40 is a susceptor in which one concave counterbore 41 is formed. The diameter of the counterbore side wall is 152.5 mm, and the width of the outer peripheral portion 42 of the susceptor is 36.2 mm. The base material of the susceptor is graphite, and the entire surface thereof is coated with a SiC film by a CVD method.
＜エピタキシャル層の形成＞
　このようなサセプタを使用してオリフラ部を有する５枚のサンプルウェーハにエピタキシャル層を膜厚が１０μｍとなるように形成した。被処理物であるウェーハや、エピタキシャル層を形成する条件は実施例と全てのサンプルウェーハで同じとして、ザグリ内での載置位置のみ変化させた。その具体例を図７に示す。 <Epitaxial layer formation>
Using such a susceptor, an epitaxial layer was formed to a thickness of 10 μm on five sample wafers having an orientation flat portion. The wafer to be processed and the conditions for forming the epitaxial layer were the same for the example and all sample wafers, and only the placement position in the counterbore was changed. A specific example is shown in FIG.
　比較例１～５では、ザグリの中心とウェーハＷの中心とがほぼ一致するように載置した（図７（ｃ）参照）。比較例６～１０では、ウェーハの位置決め手段であるザグリの側壁に、ウェーハのオリフラ部とは反対側の外周部が接触するように載置した（図７（ｄ）参照）。これによって作製されたエピタキシャル層の膜厚を測定した。尚、膜厚の測定部分は、各サンプルウェーハにおいて、図７（ａ）に示すのと同じ５点で測定した。この５点は、オリフラ付近Ｏ、中心付近Ｃ、オリフラ部とは反対側のウェーハの端部Ｅ、ＯとＣの中間点Ｒ１、ＣとＥの中間点Ｒ２である。この結果を下の表１に示した。なお、表１中の％とは、（最大膜厚－最小膜厚）／（最大膜厚＋最小膜厚）×１００（％）と定義される。
　 In Comparative Examples 1 to 5, it was placed so that the center of the counterbore and the center of the wafer W substantially coincided (see FIG. 7C). In Comparative Examples 6 to 10, the wafer was placed so that the outer peripheral portion opposite to the orientation flat portion of the wafer was in contact with the side wall of the counterbore as the wafer positioning means (see FIG. 7D). The film thickness of the epitaxial layer produced by this was measured. In addition, the measurement part of the film thickness was measured at the same five points as shown in FIG. These five points are an orientation flat vicinity O, a central vicinity C, an end E of the wafer opposite to the orientation flat part, an intermediate point R1 between O and C, and an intermediate point R2 between C and E. The results are shown in Table 1 below. In Table 1, “%” is defined as (maximum film thickness−minimum film thickness) / (maximum film thickness + minimum film thickness) × 100 (%).
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　この表１の結果より、ウェーハの位置決め手段（実施例では突起物、比較例ではザグリの側壁）内でウェーハが偏った位置に載置された場合、比較例では、Ｏ部の膜厚がより厚くなりＥ部が薄くなっている。一方実施例は、Ｏ部もＥ部も膜厚に変化が無い。５サンプルのＯ部とＥ部の差の平均は、図７（ｃ）の比較例１～５は＋０．２３μｍであるのに対して図７（ｄ）の比較例６～１０は＋０．４０μｍに広がったが、図７（ａ）の実施例１～５の場合は＋０．１１μｍであるのに対して図７（ｂ）の実施例６～１０でも＋０．１１μｍのままであった。 From the results shown in Table 1, when the wafer is placed at an offset position in the wafer positioning means (protrusions in the example, side walls of the counterbore in the comparative example), the film thickness of the O portion is larger in the comparative example. It becomes thicker and the E part is thinner. On the other hand, in the embodiment, there is no change in the film thickness in either the O portion or the E portion. The average difference between the O part and the E part of the 5 samples is +0.23 μm in Comparative Examples 1 to 5 in FIG. 7C, whereas it is +0.40 μm in Comparative Examples 6 to 10 in FIG. However, in Examples 1 to 5 in FIG. 7A, it was +0.11 μm, but in Examples 6 to 10 in FIG. 7B, it was still +0.11 μm.
　上記のような、実施例、比較例の結果より、本発明のサセプタを気相成長装置や気相成長方法に使用することで、位置決め手段である突起物内においてウェーハが偏っても、また、ウェーハにオリフラ部が形成されている場合であっても、ウェーハ面内で膜厚分布のバラツキが抑制され、均一に薄膜を気相成長させることができることが分かる。 From the results of the examples and comparative examples as described above, even when the wafer is biased in the protrusions as positioning means by using the susceptor of the present invention for the vapor phase growth apparatus and the vapor phase growth method, It can be seen that even when the orientation flat portion is formed on the wafer, the variation in the film thickness distribution is suppressed within the wafer surface, and the thin film can be uniformly vapor-phase grown.
　尚、本発明は上記実施形態に限定されるものではない。上記実施形態は例示であり、本発明の特許請求の範囲に記載された技術的思想と実質的に同一な構成を有し、同様な作用効果を奏するものは、如何なるものであっても本発明の技術範囲に包含される。 The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration substantially the same as the technical idea described in the claims of the present invention and exhibits the same function and effect. It is included in the technical scope.

Claims (5)

  1. 　気相成長装置内でウェーハを水平に載置するザグリが形成されたサセプタにおいて、
    　前記ザグリは、底面と側壁を有する円形の凹形状であり、
    　前記ザグリの側壁の直径は、前記載置するウェーハの直径より大きく、
    　前記ザグリの底面には、前記ウェーハがザグリの中央部に載置されるように該ザグリの底面から突出する複数の突起物が形成されたものであることを特徴とするサセプタ。
    　     In a susceptor in which a counterbore that horizontally places a wafer in a vapor phase growth apparatus is formed,
    The counterbore is a circular concave shape having a bottom surface and a side wall,
    The diameter of the counterbore side wall is larger than the diameter of the wafer to be placed,
    A susceptor, wherein a plurality of protrusions are formed on a bottom surface of the counterbore so as to protrude from the bottom surface of the counterbore so that the wafer is placed in a central portion of the counterbore.
  2. 　前記突起物は、少なくともウェーハに接する面が傾斜面であることを特徴とする請求項１に記載のサセプタ。
    　     The susceptor according to claim 1, wherein at least a surface of the protrusion that contacts the wafer is an inclined surface.
  3. 　前記ザグリの側壁の直径は、前記載置するウェーハの直径の１．３倍以上であることを特徴とする請求項１又は請求項２に記載のサセプタ。
    　     3. The susceptor according to claim 1, wherein a diameter of the counterbore side wall is 1.3 times or more of a diameter of a wafer to be placed.
  4. 　請求項１ないし請求項３のいずれか１項に記載のサセプタを具備することを特徴とする気相成長装置。
    　     A vapor phase growth apparatus comprising the susceptor according to any one of claims 1 to 3.
  5. 　請求項１ないし請求項３のいずれか１項に記載のサセプタを使用してウェーハに薄膜を気相成長させることを特徴とするウェーハの気相成長方法。 A vapor phase growth method for a wafer, characterized in that a thin film is vapor grown on a wafer using the susceptor according to any one of claims 1 to 3.
PCT/JP2009/000098 2008-01-24 2009-01-14 Susceptor and vapor phase growth system and vapor phase growth method WO2009093417A1 (en)

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JP2014216605A (en) * 2013-04-30 2014-11-17 住友電気工業株式会社 Manufacturing method and manufacturing apparatus of semiconductor substrate

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