JP2008211109A - Vapor phase growth system and vapor phase epitaxial growth method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vapor phase growth system that reduces fast-sticking between a substrate generated through vapor phase epitaxial filming and a support member, and to provide a vapor phase epitaxial growth method. <P>SOLUTION: The vapor phase growth system has a chamber 107, a supply section 108 for supplying a raw material gas into the chamber 107, a revolvable holder 102 arranged in the chamber 107 having a wafer 101 placed on a plane 103 and having a concave part 104 formed at a position directly beneath the outer edge of the wafer 101 on the plane 103; and an exhaust section 109 for exhausting the raw material gas after vapor phase epitaxy from the inside of the chamber 101, whereby even if a vapor phase epitaxial film is produced on the wafer 101 and the holder 102, the vapor phase epitaxial film generated on each of them will not be brought into contact with the other, and the wafer 101 and the holder 102 can be made so as not to be fixed firmly. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vapor phase growth apparatus and a vapor phase growth method, and relates to the shape of a support member that supports a substrate such as a silicon wafer in an epitaxial growth apparatus.

In the manufacture of semiconductor devices such as ultra-high speed bipolar and ultra-high speed CMOS, single crystal epitaxial growth technology with controlled impurity concentration and film thickness is indispensable for improving the performance of the device.
For epitaxial growth in which a single crystal film is formed on a semiconductor substrate such as a silicon wafer, atmospheric pressure chemical vapor deposition is generally used, and in some cases, low pressure chemical vapor deposition (LPCVD) is used. A semiconductor substrate such as a silicon wafer is disposed in the vapor phase growth reactor, and the vapor phase growth reactor is maintained at a normal pressure (0.1 MPa (760 Torr)) or in a vacuum atmosphere of a predetermined degree of vacuum. A source gas containing a silicon source and a dopant such as a boron compound, an arsenic compound, or a phosphorus compound is supplied while heating and rotating the semiconductor substrate. Then, a pyrolysis reaction or a hydrogen reduction reaction of the source gas is performed on the surface of the heated semiconductor substrate to generate a vapor growth film doped with boron (B), phosphorus (P), or arsenic (As). (See Patent Document 1).

  The epitaxial growth technique is also used for manufacturing a semiconductor element that requires a relatively thick crystal film, such as an IGBT (Insulated Gate Bipolar Transistor). For example, while a simple MOS device or the like requires only a film thickness of several μm or less, a super-high speed bipolar device requires a vapor growth film having a film thickness of several μm to several tens of μm. In order to achieve this, an epitaxial growth technique is used to generate a crystal film having a required film thickness.

FIG. 9 is a conceptual diagram seen from above showing an example of a state in which a wafer is placed on a holder accommodated in a chamber (not shown). FIG. 10 is a conceptual diagram showing a cross section in a state where a wafer is placed on the holder shown in FIG.
A holder 402 (also referred to as a susceptor), which is a support member for the wafer 401, is formed with a first-stage opening having a diameter slightly larger than the diameter of the wafer 401, and its bottom surface is in contact with the back surface of the wafer 401. It is formed to support. Further, a second-stage opening that penetrates with a diameter smaller than the diameter of the wafer 401 is formed at the center of the first-stage opening. Then, the wafer 401 is placed in such a first-stage opening. In this state, while rotating the holder 402, a vapor phase growth film is generated by thermal decomposition reaction or hydrogen reduction reaction of the supplied source gas while rotating the wafer 401.
JP-A-9-194296

In the apparatus as described above, when a source gas is supplied into a chamber (not shown) in which the wafer 401 is accommodated and heating is performed while the holder 402 is rotated, a vapor growth film is generated on the wafer 401. Further, since the holder 402 is also heated to a temperature similar to that of the wafer 401, the source gas undergoes a thermal decomposition reaction or a hydrogen reduction reaction on the surface of the holder 402, and a vapor growth film is generated. Then, as shown in FIG. 11, the vapor phase growth film generated on the side surface portion of the wafer 401 and the vapor phase growth film generated on the surface of the holder 402 come into contact with each other to be fixed.
Here, when the wafer 401 is transported after the vapor phase growth, the above-mentioned fixing portion is broken and released. The fragment of the free vapor grown film remains as particles in the above-described chamber and is mixed as an impurity in the vapor grown film generated during the subsequent vapor growth, thereby reducing the quality of the produced wafer. There was a problem of inviting.
Further, when the wafer 401 is fixed to the holder 402 at the outer edge portion, heat conduction from the holder 402 to the wafer 401 is not performed as set, and the temperature in the surface of the wafer 401 becomes non-uniform. In some cases, a high-quality single crystal film may not be generated on the wafer 401. As a result, there is a problem that a vapor phase growth film having a constant quality is not generated in the entire surface of the wafer 401, and the quality of the produced wafer 401 is deteriorated.
Further, when the wafer 401 is transported after vapor phase growth, since it is fixed to the holder 402, it cannot be transported smoothly, and there is a problem that the wafer 401 is damaged, damaged, or the holder 402 is damaged. It was.

  The present invention provides a vapor phase growth apparatus and a vapor phase growth method capable of overcoming such problems and reducing sticking between a substrate and a support member by a vapor phase growth film to be generated.

The vapor phase growth apparatus of the present invention is
A chamber;
A supply unit for supplying a source gas into the chamber;
A rotatable holder that is disposed in the chamber, places the substrate on the surface, and has a recess formed at a position directly below the outer edge of the substrate on the surface;
An exhaust section for exhausting the source gas after vapor phase growth from the chamber;
It is characterized by providing.

  With this configuration, it is possible to perform vapor phase growth without bringing the outer edge portion of the substrate into contact with the holder, and to prevent the vapor phase growth film generated on the side surface portion of the substrate from being brought into contact with the vapor phase growth film generated at the holder. Can do. Therefore, it is possible to prevent the vapor deposition films generated on the substrate and the holder from being fixed to each other.

  Moreover, it is preferable that the depth of the above-mentioned recess is formed to a depth equal to or greater than the thickness of the vapor phase growth film generated on the substrate.

  With this configuration, even if a vapor phase growth film is generated in the recess, it is possible to prevent the vapor phase growth film from reaching the back surface of the outer edge portion of the placed substrate. Therefore, it is possible to prevent the substrate and the holder from being fixed.

  Furthermore, it is preferable that the holder has an opening having the above-mentioned surface as a bottom surface, and the side surface of the opening has a plurality of convex portions so as to surround the substrate.

  With this configuration, when the side surface portion of the substrate and the side surface of the opening are in contact, the contact can be a contact with a point or a line, not a contact with a surface. As a result, the contact area can be reduced, so that the side surface portion of the substrate and the holder can be prevented from sticking.

  In addition, it is preferable that the plurality of convex portions described above are arranged at substantially equal intervals on the side surface of the opening.

  With such a configuration, it is possible to prevent the substrate for vapor phase growth from being detached from the holder when receiving a lateral force such as a centrifugal force. In addition, when the substrate that has received the force in the lateral direction is supported by some of the above-described convex portions, the convex portions are arranged at substantially equal intervals. Can also be supported in the same state.

Furthermore, the vapor phase growth method of the present invention comprises:
A vapor phase growth method for performing vapor phase growth by supplying a source gas to a substrate heated by a heater in a chamber,
The substrate is supported by a rotatable holder having a surface in which a recess having a depth equal to or greater than the thickness of the vapor phase growth film generated on the substrate is provided immediately below the outer edge of the substrate,
It is preferable to perform the vapor phase growth by supplying the source gas from the supply unit toward the substrate.

  With this configuration, even when the vapor phase growth film is generated on the substrate by the above-described vapor phase growth method, a recess deeper than the thickness of the generated vapor phase growth film is formed immediately below the outer edge portion of the substrate. Therefore, it is possible to prevent the substrate and the holder from being fixed.

According to the present invention, vapor phase growth can be performed in a state where the outer edge portion of the substrate placed on the holder is not in contact with the holder. By providing a recess in the holder, it is possible to float the outer edge of the substrate where the substrate and the holder are easily fixed when the substrate is placed, and as a result, preventing the substrate and the holder from sticking to each other Can do. For this reason, it is possible to reduce the possibility of damaging or damaging the substrate or damaging the holder each time the substrate subjected to vapor phase growth is transported.
Further, when the substrate after the vapor phase growth is transported, the vapor phase growth film to which the substrate and the holder are fixed is broken and can be prevented from remaining in the chamber as particles. Therefore, it is possible to prevent a substrate produced later from being contaminated by particles.
As a result, the working efficiency and yield of the vapor phase growth apparatus can be improved, and further, the quality of the produced substrate can be prevented from being lowered.

(Embodiment 1)
First, the first embodiment will be described in detail with reference to FIG.
FIG. 1 is a conceptual diagram showing a configuration of a vapor phase growth apparatus according to the first embodiment.
A vapor phase growth apparatus 100 in FIG. 1 heats a chamber 107 that houses a wafer 101, a holder 102 on which a surface 103 on which the wafer 101 is placed, a rotating unit 106 that is connected to the holder 102, and the wafer 101. An in-heater 110 and an out-heater 111 are provided.
The chamber 107 is provided with a flow path serving as a source gas supply section 108 supplied for performing vapor phase growth and a flow path serving as an exhaust section 109 for exhausting the source gas after the vapor phase growth reaction. Further, a shower head 112 is connected to the supply unit 108, and the source gas is uniformly supplied to the wafer 101 via the shower head 112. Then, the raw material gas that has undergone the thermal decomposition reaction or hydrogen reduction reaction on the surface of the wafer 101 is exhausted out of the chamber 107 through the exhaust unit 109.
In FIG. 1, components other than those necessary for describing the first embodiment are omitted, and the scales and the like of each member are not matched with the actual ones. Hereinafter, the same applies to each drawing.

The holder 102 has a shape obtained by processing a circular plate-shaped member, and a two-stage opening is formed at the center thereof.
The first-stage opening is formed to a predetermined depth, and the back surface of the wafer 101 is supported on and supported by the surface 103 that is the bottom surface. Then, a groove 104 (an example of a recess) is formed at a position of the surface 103 immediately below the outer edge of the wafer 101 with a predetermined width and depth over the entire circumference, and the outer edge of the substrate 101 and the holder 102 are brought into contact with each other. It can be mounted without letting it. The second stage opening is formed at the center of the bottom surface of the first stage and penetrates therethrough.

  Further, on the side surface of the first stage opening, three or more convex portions 105 are formed so as to surround the wafer 101 when the wafer 101 is placed on the surface 103. The convex portion 105 is formed in a convex shape toward the center of the wafer 101. Further, the upper end of the convex portion 105 is formed at a height that does not exceed the height of the upper surface of the holder 102.

  The holder 102 is connected to and supported by a rotating unit 106 that is rotated by a rotation mechanism (not shown), and rotates about the center of the holder 102 that is orthogonal to the wafer 101 surface as a rotation axis. As a result, the wafer 101 placed on the surface 103 formed on the holder 102 can be rotated in the same manner.

Two heaters for heating the wafer 101 are arranged below the wafer 101.
First, the in-heater 110 is disposed so as to heat the central portion of the wafer 101. Further, an outheater 111 is disposed so as to heat the outer peripheral portion of the wafer 101 and the holder 102 simultaneously. Heating the outer periphery of the wafer 101 where heat easily escapes because of contact with the holder 102 via the surface 103 together with the holder 102 makes it possible to control the temperature of the wafer 101 rather than controlling the temperature of the wafer 101 with only one in-heater 110 system. The uniformity of the temperature distribution in the surface can be improved.

  Holder 102, shower head 112, in-heater 110, and out-heater 111 are accommodated in chamber 107. The rotation unit 106 is connected to a rotation mechanism (not shown) provided outside the chamber 107. Further, the shower head 112 described above is connected to the supply unit 108, and a pipe is connected to the outside of the chamber 107.

  Then, the wafer 101 is accommodated in a chamber 107 maintained at normal pressure or a predetermined degree of vacuum. The wafer 101 placed on the holder 102 is rotated by the rotation of the holder 102 and the rotating unit 106 while being heated by the in-heater 110 and the out-heater 111. By supplying the source gas from the supply unit 108 through the shower head 112 to the chamber 107 in this state, the environment of the vapor phase growth reaction can be adjusted.

The source gas supplied here is any one of silane (SiH ₄ ), dichlorosilane (SiH ₂ Cl ₂ ), trichlorosilane (SiHCl ₃ ), etc., which is a silicon film forming gas, and H ₂ which is a carrier gas. It is comprised by adding a predetermined dopant gas to this mixed gas.
Boron-based diborane (B ₂ H ₆ ), phosphorus-based phosphine (PH ₃ ), and the like are known as dopant gases. When diborane is added, a vapor phase growth film showing p-type conductivity and when phosphine is added, an n-type conductivity film is generated.

  The source gas undergoes a thermal decomposition reaction or a hydrogen reduction reaction on the heated wafer 101 in the chamber 107 in which the environment for the vapor phase growth reaction is prepared, thereby generating a vapor phase growth film on the surface of the wafer 101. At this time, the source gas supplied from the supply unit 108 is ejected from a plurality of through holes provided in a uniform distribution on the surface of the shower head 112 facing the wafer 101. Therefore, the source gas can be uniformly supplied to the surface of the wafer 101, and as a result, a vapor growth film can be uniformly generated on the surface of the wafer 101.

FIG. 2 is a conceptual diagram showing a cross section of the holder 102 on which the wafer 101 is placed in the first embodiment.
A groove 104 is formed on the surface 103 in FIG. 2 so as to be positioned immediately below the outer edge of the wafer 101 when the wafer 101 is placed on the holder 102. Since the wafer 101 is supported from the back surface by the holder 102 via the surface 103, the wafer 101 can be stably rotated by the rotation of the holder 102 accompanying the rotation of the rotating unit 106. Then, the wafer 101 is heated and a source gas is supplied into the chamber 107 to perform vapor phase growth to generate a vapor phase growth film on the wafer 101 surface. At this time, a vapor phase growth film is generated not only on the surface of the wafer 101 but also on the holder 102. However, since the groove 104 is formed immediately below the outer edge portion of the wafer 101, which is an easily fixed portion, the wafer 101 The vapor phase growth film generated on the side surface portion is not brought into contact with the vapor phase growth film generated in the groove 104. As a result, the wafer 101 and the holder 102 can be prevented from being fixed.

  In addition, the depth of the above-described groove 104 may be set deeper than the film thickness of the vapor growth film generated on the wafer 101. Furthermore, it is better if it is twice or more. For example, when the assumed film thickness of the vapor phase growth film is 100 μm, it is preferable that the groove 104 is formed to have a depth of 0.2 mm or more, assuming a depth of twice or more the film thickness.

  As shown in FIGS. 3 and 4, a plurality of, for example, eight convex portions 105 in FIG. 3 are provided on the side surface of the first opening, and the convex portions 105 are convex toward the center of the wafer 101. It is formed.

  As a result, the wafer 101 and the side surface of the first opening are in contact with each other as compared with the conventional method in which the side surface of the first opening and the side surface of the wafer 101 are in contact with each other with a large area without providing the convex portion 105. The area can be reduced. As a result, even if the side surface of the wafer 101 and the tip of the convex portion 105 come into contact with each other, the contact between the wafer 101 and the holder 102 can be reduced because the contact is made in a narrow area close to a line or a point. Therefore, it is possible to reduce the risk of damage, damage, or damage to the holder 102 when the wafer 101 that has undergone vapor phase growth is transported.

  Further, when the wafer 101 is moved by receiving a lateral force such as a centrifugal force when the wafer 101 is rotated with the rotation of the holder 102, the protrusion 105 is supported by some of the plurality of the protrusions 105. At this time, since the convex portions 105 are arranged at substantially equal intervals, they can be supported in the same state regardless of the combination of the convex portions 105 to be supported.

  Further, in the first embodiment, eight convex portions are arranged on the holder 102, but the number of arrangement is not limited to this. For example, if the number of the convex portions 105 is increased, the accuracy of the lateral position of the wafer 101 can be increased. Conversely, if the number of the convex portions 105 is decreased, the area in contact with the wafer 101 can be further reduced. Thus, sticking between the wafer 101 and the holder 102 can be further reduced.

FIG. 5 is a conceptual diagram showing another example of the holder 202 on which the wafer 101 is placed.
A groove 203 is formed on the surface 203 which is the bottom surface of the first opening formed in the holder 202 so as to be positioned immediately below the outer edge portion of the wafer 101 when the wafer 101 is placed on the holder 202. . The groove 204 is semicircular and is dug to a predetermined width and depth, and is formed over the entire circumference of the surface 203. Thus, the shape of the cross section of the groove is not limited to a rectangle.

By providing the semicircular groove 204 on the surface 203, there is an effect that cleaning can be easily performed as compared with the case of cleaning the rectangular groove after the vapor phase growth reaction. Therefore, the holder 102 in which the semicircular groove 204 is formed is suitable for repeated use.
Although the groove 204 is formed in a semicircular shape here, the provision of the groove 204 makes it difficult for the wafer 101 and the holder 102 to be fixed, and the arrangement of the convex portion 105 is the same as described with reference to FIGS. Therefore, the description is omitted here.

FIG. 6 is a conceptual diagram for explaining the flow of the source gas at the time of vapor phase growth when using the holder 302 in which the upper surface of the holder 302 is formed at a position higher than the upper surface of the wafer 101.
FIG. 7 is a conceptual diagram for explaining the flow of the source gas at the time of vapor phase growth in the case of using the holder 102 in the embodiment of the present invention.
As shown in FIG. 6, when a holder whose upper surface of the holder 302 is higher than the upper surface of the wafer 101 is used, the source gas supplied from the shower head 112 hits the surface of the wafer 101 and changes the traveling direction in a substantially horizontal direction. Then, while performing a thermal decomposition reaction or a hydrogen reduction reaction, it flows to an exhaust section 109 connected to a vacuum pump (not shown). However, since the upper surface of the holder 302 is located higher than the upper surface of the wafer 101, the gas flow 313 is prevented from flowing by the side surface of the first stage opening formed in the holder 302 and becomes turbulent. On the other hand, when the holder 102 according to the embodiment of the present invention is used as shown in FIG. 7, a smooth gas flow 113 can be formed without causing a turbulent flow of the raw material gas, and the entire surface of the wafer 101 is uniform. Vapor phase growth can be performed.
7 illustrates the case where the height of the upper surface of the wafer 101 is the same as the height of the upper surface of the holder 102, the height of the upper surface of the holder 102 is the position of the upper surface of the wafer 101. Needless to say, the flow of the gas flow 113 is not obstructed even when the height of the gas flow 113 is lower.
The holder 102 in the embodiment of the present invention is formed to have the same height as the position of the upper surface of the wafer 101 or lower than the height of the position of the upper surface of the wafer 101. Therefore, the gas flow 113 of the source gas that has undergone vapor phase growth on the wafer 101 is not obstructed by the side surface of the first stage opening provided in the holder 102. Therefore, the gas flow 113 flows to the exhaust part 109 while forming a laminar flow. As a result, in this embodiment, a uniform vapor deposition film can be generated on the entire surface of the wafer 101.

FIG. 8 is a flowchart showing the vapor phase growth method of the first embodiment.
In this vapor phase growth method,
First, as a substrate supporting step (S101), the wafer 101 is placed on the holder 102 having the grooves 104.
Next, as a source gas supply step (S <b> 102), source gas is supplied from the supply unit 113 toward the wafer 101.
Then, as the vapor growth film generation step (S103), the raw material gas is supplied to the wafer 101 heated by the in-heater 110 and the out-heater 111 while being rotated by the rotation of the holder 102, and the vapor growth film is generated. .

  By using the above-described vapor phase growth method, the vapor phase growth film generated on the side surface of the wafer 101 and the vapor phase growth film generated on the holder are not brought into contact with each other. As a result, the wafer 101 and the holder 102 are fixed, so that the wafer can be prevented from being damaged or damaged during the transfer of the wafer 101, or the holder can be prevented from being damaged.

  The embodiments have been described above with reference to specific examples. The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention.

  In the present invention, the convex portion 105 provided on the holder 102 is exemplified as a semicircular shape. However, the shape of the convex portion 105, such as a trapezoidal shape or a spherical shape, can reduce the contact surface with the wafer 101 and can be supported stably. If it is a thing, it does not ask the shape.

  In the present invention, the epitaxial growth apparatus has been described as an example of the vapor phase growth apparatus. However, the present invention is not limited to this, and any apparatus for vapor phase growth of a predetermined crystal film on the wafer surface may be used. For example, it may be an apparatus intended to grow a polysilicon film.

  In addition, although descriptions of parts that are not directly required for the description of the present invention, such as the apparatus configuration and control method, are omitted, the required apparatus configuration, control method, and the like can be appropriately selected and used.

  In addition, all the vapor phase growth apparatuses that include the elements of the present invention and can be appropriately modified by those skilled in the art, and the shapes of the support members are included in the scope of the present invention.

It is a conceptual diagram which shows the structure of the vapor phase growth apparatus in this invention. It is the conceptual diagram cut in the state where the wafer was mounted in the holder of a 1st embodiment of the present invention. It is a conceptual diagram of the upper part of the state which mounted the wafer in the holder of the 1st Embodiment of this invention. It is the conceptual diagram which showed the cross section of the holder which mounted the wafer in the 1st Embodiment of this invention from diagonally. It is the conceptual diagram which showed the cross section of the state which mounted the wafer in the holder of the other example of the 1st Embodiment of this invention from diagonally. It is the conceptual diagram which showed the flow of the source gas in the vapor phase growth apparatus using the holder whose upper surface position is higher than the height of the upper surface position of the wafer. It is the conceptual diagram which showed the flow of the source gas on the wafer in this invention. It is the flowchart which showed the process of the vapor phase growth method of this invention. It is the conceptual diagram which showed the holder with which the wafer of the conventional vapor phase growth apparatus was mounted from upper direction. It is the conceptual diagram which showed the cross section of the holder in which the wafer in the conventional vapor phase growth apparatus was mounted. It is the conceptual diagram which showed a mode that the vapor phase growth film produced | generated on the wafer and the vapor phase growth film produced | generated on the holder adhered in the conventional vapor phase growth apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Vapor growth apparatus 101, 401 ... Wafer 102, 302, 402 ... Holder 103, 203, 403 ... Surface 104, 204 ... Groove 105 ... Convex part 106 ... Rotation part 107 ... Chamber 108 ... Supply part 109 ... exhaust part 110 ... in heater 111 ... out heater 112 ... shower head 113, 313 ... gas flow

Claims (5)

A chamber;
A supply unit for supplying a source gas into the chamber;
A holder that is disposed in the chamber, places a substrate on the surface, and has a recess formed at a position directly below the outer edge of the substrate on the surface;
An exhaust section for exhausting the source gas after vapor phase growth from within the chamber;
A vapor phase growth apparatus comprising:   The vapor deposition apparatus according to claim 1, wherein the depth of the recess is formed to a depth greater than or equal to a thickness of a vapor deposition film generated on the substrate.   3. The holder according to claim 1, wherein the holder has an opening having the surface as a bottom surface, and has a plurality of convex portions on a side surface of the opening so as to surround the substrate. Any one of the vapor phase growth apparatuses.   4. The vapor phase growth apparatus according to claim 1, wherein the plurality of protrusions are arranged at substantially equal intervals on a side surface of the opening. 5. A vapor phase growth method for performing vapor phase growth by supplying a source gas to a substrate heated by a heater in a chamber,
The concave portion formed with a depth equal to or greater than the film thickness of the vapor phase growth film generated on the substrate supports the substrate by a holder having a surface provided immediately below the outer edge portion of the substrate,
A vapor phase growth method comprising performing the vapor phase growth by supplying the source gas from the supply unit toward the substrate.

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