JP2007224375A - Vapor deposition apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vapor deposition apparatus having a structure comprising such a support and a heat source as to keep temperature distribution within a substrate surface more uniform. <P>SOLUTION: In a vapor deposition apparatus for forming a film on a silicon wafer 101 in a chamber 120 to which a passage 122 for supplying a gas and a passage 124 for exhausting the gas are connected, this vapor deposition apparatus comprises: a holder 110 which has an annular salient 112 on a rear face and supports a silicon wafer 101; an outer heater 150 which is arranged on an outer side than a peripheral edge of the salient 112 so that the surface is located in the more holder 110 side than the top of the salient 112; and an inner heater 160 which is arranged more apart from the holder 110. Thus structured vapor deposition apparatus can improve a temperature distribution within a substrate surface. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vapor phase growth apparatus, for example, a shape and an arrangement position of a support member (support base) for supporting a substrate such as a silicon wafer in an epitaxial growth apparatus and a heater for heating the substrate.

In the manufacture of semiconductor devices such as ultrahigh-speed bipolar and ultrahigh-speed CMOS, single crystal epitaxial growth technology with controlled impurity concentration and film thickness is indispensable for improving device performance.
In general, an atmospheric pressure chemical vapor deposition method is used for epitaxial growth of a single crystal thin film on a semiconductor substrate such as a silicon wafer, and a low pressure chemical vapor deposition (LP-CVD) method is used in some cases. ing. A semiconductor substrate such as a silicon wafer is placed in the reaction vessel, and the semiconductor substrate is heated and rotated in a state where the reaction vessel is maintained in a normal pressure (0.1 MPa (760 Torr)) atmosphere or a vacuum atmosphere of a predetermined degree of vacuum. However, a source gas containing a silicon source and a dopant such as a boron compound, an arsenic compound, or a phosphorus compound is supplied. Then, a silicon epitaxial film doped with boron (B), phosphorus (P), or arsenic (As) is grown by performing thermal decomposition or hydrogen reduction reaction of the source gas on the surface of the heated semiconductor substrate. Manufacture (for example, see Patent Document 1).

  Epitaxial growth technology is also used in the manufacture of power semiconductors, for example, the manufacture of IGBTs (insulated gate bipolar transistors). In a power semiconductor such as IGBT, for example, a silicon epitaxial film having a thickness of several tens of μm or more is required.

FIG. 7 is a conceptual diagram showing the shape and arrangement of conventional holders and heaters.
FIG. 8 is a diagram illustrating an example of the dimensions of the arrangement configuration illustrated in FIG. 7.
A holder 210 (also referred to as a susceptor) serving as a support member (support base) for the silicon wafer 200 is disposed in the chamber of the apparatus. The holder 210 is formed with a counterbore having a diameter slightly larger than the diameter of the silicon wafer 200. Then, the silicon wafer 200 is placed in such a counterbored hole. In this state, the silicon wafer 200 is rotated by rotating the holder 210 with the rotating member 171, and a silicon epitaxial film is grown by thermal decomposition or hydrogen reduction reaction of the supplied source gas. Further, an outheater 151 for heating the holder 210 is disposed on the back side of the holder 210 with a dimension ₁₁ away from the back side of the holder 210. The outheater 151 is formed in an annular shape, and the inner peripheral end thereof is disposed at a distance of l ₂ from the outer peripheral end of the silicon wafer 200. Further, at the lower part of the outer heater 151, inner heater 161 for heating the back surface of the silicon wafer 200 with dimensions l ₃ away from the back surface of the outer heater 151 is arranged. Also, out-heater 151 is formed to a width dimension _{l 4.} In such an arrangement, the distance from the back surface of the silicon wafer 200 to the in-heater 161 is the dimension l ₅ . And, for example, as shown in FIG. 8, it was configured with l ₁ = 5 mm, l ₂ = 15 mm, l ₃ = 4.5 mm, l ₄ = 10 mm, and l ₅ = 12.1 mm.
JP-A-9-194296

  As described above, in order to uniformly grow the silicon epitaxial film on the silicon wafer 200, the silicon wafer 200 is heated by the in-heater 161, but the heat escapes through the holder 210 that serves as a support for the silicon wafer 200. Therefore, the outheater 151 is arranged so as to heat the holder 210 separately. However, in the arrangement configuration having dimensions as shown in FIG. 8, the temperature distribution in the substrate surface is not uniform, and in particular, the film thickness uniformity of the edge portion of the substrate such as the silicon wafer 200 is deteriorated. There was a problem.

  It is an object of the present invention to provide a vapor phase growth apparatus having a configuration of a support base and a heat source that overcomes such problems and keeps the temperature distribution in the substrate surface more uniform.

The vapor phase growth apparatus of one embodiment of the present invention includes:
In a vapor phase growth apparatus for forming a film on a substrate using a gas in a chamber connected to a first flow path for supplying gas and a second flow path for exhausting gas,
A support having an annular convex portion on the back surface and supporting the substrate on the front surface side;
A first heat source disposed on the back surface side of the support base and outside the outer peripheral end of the convex portion so that the surface position is located on the support base side with respect to the tip of the convex portion described above,
A second heat source disposed further away from the first heat source on the back side of the support base;
It is provided with.

  By disposing the surface position of the first heat source outside the outer peripheral end of the convex portion closer to the support base than the tip of the convex portion, the radiant heat from the first heat source can be shielded by the convex portion. Therefore, leakage of radiant heat from the first heat source to the substrate side can be suppressed.

  The first heat source is formed in an annular shape, and the distance from the inner peripheral end of the first heat source to the outer peripheral end of the substrate is a radius from the outer peripheral end of the first heat source to the inner peripheral end of the first heat source. It is arranged to be shorter than the length in the direction.

  With this configuration, the distance between the first heat source and the substrate can be made shorter than before. As a result, the necessary amount of heat can be easily transmitted to the substrate via the support base.

Here, the support base is formed in an annular shape,
In particular, the first heat source has a radial length from the outer peripheral end of the first heat source to the inner peripheral end of the first heat source, and a radial length from the outer peripheral end of the support base to the inner peripheral end of the support base. It is preferable that it is formed so as to be 45 to 59%.

  By forming the annular first heat source in such a length, a necessary heat transfer area can be obtained.

  Further, the first and second heat sources are arranged so that the distance from the back surface of the first heat source to the surface of the second heat source is longer than the distance from the back surface of the support base to the surface of the first heat source. It is characterized by that.

  In particular, the first and second heat sources are set so that the distance from the back surface of the first heat source to the surface of the second heat source is at least seven times the distance from the back surface of the support base to the surface of the first heat source. Arrangement is preferred.

  According to the present invention, the temperature distribution in the substrate surface can be improved, and the film thickness uniformity can be improved.

Embodiment 1 FIG.
In process development of a single wafer epitaxial growth apparatus which is an example of a vapor phase growth apparatus, film thickness uniformity is required. It became clear that the temperature distribution of the silicon wafer is important as a point that influences the film thickness uniformity. In particular, there is a peculiar phenomenon that is different from the so-called edge effect called the edge effect, which is seen at a wafer edge number of mm. How to mitigate this singular phenomenon is necessary to obtain a good temperature distribution. In the first embodiment, a holder shape and a heater layout in which the temperature distribution in the wafer surface, which is also verified from the results of simulation, is optimized will be described. Hereinafter, it demonstrates using drawing.

FIG. 1 is a conceptual diagram showing the configuration of the epitaxial growth apparatus in the first embodiment.
In FIG. 1, an epitaxial growth apparatus 100 as an example of a vapor phase growth apparatus includes a holder (also referred to as a susceptor) 110 as an example of a support base, a chamber 120, a shower head 130, a vacuum pump 140, a pressure control valve 142, an outheater. 150, an in-heater 160, and a rotating member 170 are provided. The chamber 120 is connected to a flow path 122 for supplying gas and a flow path 124 for exhausting gas. The flow path 122 is connected to the shower head 130. In FIG. 1, components other than those necessary for describing the first embodiment are omitted. Further, the scale and the like are not matched with the actual product (hereinafter, the same applies in each drawing).

  The holder 110 is formed in an annular shape, and has an opening that penetrates a predetermined inner diameter. Then, the silicon wafer 101 is supported by contacting the back surface of the silicon wafer 101 at the lower surface of the counterbore hole 116 dug to a predetermined depth perpendicularly or at a predetermined angle from the upper surface side.

  The holder 110 is disposed on a rotating member 170 that can be rotated about a center line of the silicon wafer 101 surface orthogonal to the silicon wafer 101 surface by a rotation mechanism (not shown). Then, the holder 110 can rotate the silicon wafer 101 by rotating together with the rotating member 170.

  An out-heater 150 (an example of a first heat source) and an in-heater 160 (an example of a second heat source), which are examples of heat sources, are disposed on the back side of the holder 110. The holder 110 can be heated by the outheater 150. The in-heater 160 is disposed below the out-heater 150, and the silicon wafer 101 can be heated by the in-heater 160. In addition to the in-heater 160, an out-heater 150 for heating the holder 110 is provided in order to suppress the heat radiation of the outer periphery of the silicon wafer 101 where heat easily escapes to the holder 110. The internal temperature uniformity can be improved.

  The holder 110, the out heater 150, the in heater 160, the shower head 130, and the rotating member 170 are disposed in the chamber 120. The rotating member 170 extends from the chamber 120 to the rotating mechanism (not shown) outside the chamber 120. The shower head 130 has a pipe extending from the inside of the chamber 120 to the outside of the chamber 120.

  Then, the silicon wafer 101 and the holder 110 are heated by the outheater 150 and the inheater 160 in a state in which the inside of the chamber 120 serving as a reaction container is maintained at a normal pressure or a vacuum atmosphere of a predetermined degree of vacuum by the vacuum pump 140. A source gas serving as a silicon source is supplied from the shower head 130 into the chamber 120 while rotating the silicon wafer 101 at a predetermined rotational speed by the rotation of 110. Then, the raw material gas is thermally decomposed or reduced with hydrogen on the surface of the heated silicon wafer 101 to grow a silicon epitaxial film on the surface of the silicon wafer 101. The pressure in the chamber 120 may be adjusted to a normal pressure or a vacuum atmosphere with a predetermined degree of vacuum using the pressure control valve 142, for example. Alternatively, when used at normal pressure, a configuration without the vacuum pump 140 or the pressure control valve 142 may be used. In the shower head 130, the source gas supplied from outside the chamber 120 is discharged from the plurality of through holes through the buffer inside the shower head 130, so that the source gas is uniformly supplied onto the silicon wafer 101. can do. Further, by making the pressure of the holder 110 and the rotating member 170 the same inside and outside (the pressure of the atmosphere on the front surface side of the silicon wafer 101 and the pressure of the atmosphere on the back surface side are the same), the source gas is moved inside the rotating member 170 or the rotating mechanism. It is possible to prevent going into the inside. Similarly, it is possible to prevent a purge gas or the like on the rotating mechanism side (not shown) from leaking into the chamber (the atmosphere on the surface side of the silicon wafer 101).

FIG. 2 is a diagram showing an example of the appearance of the epitaxial growth apparatus system.
As shown in FIG. 2, the epitaxial growth apparatus system 300 is entirely surrounded by a casing.
FIG. 3 is a diagram showing an example of a unit configuration of the epitaxial growth apparatus system.
In the epitaxial growth apparatus system 300, a silicon wafer 101 set in a cassette placed on a cassette stage (C / S) 310 or a cassette stage (C / S) 312 is loaded into a load lock (L / L) chamber by a transfer robot 350. It is conveyed in 320. Then, the silicon wafer 101 is unloaded from the L / L chamber 320 into the transfer chamber 330 by the transfer robot 332 disposed in the transfer chamber 330. Then, the unloaded silicon wafer 101 is transferred into the chamber 120 of the epitaxial growth apparatus 100, and a silicon epitaxial film is formed on the surface of the silicon wafer 101 by the epitaxial growth method. The silicon wafer 101 on which the silicon epitaxial film is formed is again carried out from the epitaxial growth apparatus 100 into the transfer chamber 330 by the transfer robot 332. The unloaded silicon wafer 101 is transferred to the L / L chamber 320 and then placed on the cassette stage (C / S) 310 or the cassette stage (C / S) 312 from the L / L chamber 320 by the transfer robot 350. Is returned to the cassette. In the epitaxial growth apparatus system 300 shown in FIG. 3, two chambers 120 and two L / L chambers 320 of the epitaxial growth apparatus 100 are mounted, and throughput can be improved.

FIG. 4 is a conceptual cross-sectional view for explaining details of the holder shape and the heater layout in the first embodiment.
On the back surface of the holder 110, an annular convex portion 112 (velo) protruding downward is formed. In FIG. 4, the convex portion 112 extends in a direction perpendicular to the back surface of the holder 110, that is, directly below, but is not limited thereto, and may extend obliquely downward at a predetermined angle. .

The out-heater 150 having a sheet-like front surface and back surface and formed in an annular shape is disposed at a lower portion of the holder 110, that is, on the back surface side of the holder 110, with a predetermined dimension ₁₁ away from the back surface of the holder 110. With such an arrangement, the holder 110 can be heated by radiant heat from the outheater 150. The outheater 150 is disposed outside the outer peripheral end of the convex portion 112. In other words, the inner peripheral end of the outheater 150 is disposed outside the outer peripheral end of the convex portion 112. And it arrange | positions so that the surface position of the out heater 150 may be located in the holder 110 side rather than the front-end | tip of the convex part 112. FIG. With such an arrangement, the radiant heat from the outheater 150 is shielded by the convex portion 112, and it is possible to prevent heat from leaking directly to the silicon wafer 101. For example, it is desirable that the protruding height of the convex portion 112 is 2 to 4 mm. The outheater 150 is preferably arranged such that the surface position of the outheater 150 is positioned (entered) on the holder 110 side by 0.5 mm or more from the tip of the convex portion 112. The distance dimension l ₁ between the front surface of the outheater 150 and the back surface of the holder 110 is preferably 1.5 mm, for example.

Also, the distance l ₂ from the inner peripheral end of the outer heater 150 to the outer edge of the silicon wafer 101, the radial length from the outer peripheral end of the outer heater 150 to the inner peripheral edge of the out-heater 150, i.e., the outer heater 150 The outheater 150 is arranged so as to be shorter than the width dimension l ₄ . The width dimension l ₄ of the outheater 150 is set so that a necessary heat transfer area can be obtained. The width dimension l ₄ of the outheater 150 is formed to be 45 to 59% of the radial length from the outer peripheral end of the holder 110 to the inner peripheral end of the holder 110, that is, the width dimension l ₆ of the holder 110. It is preferable. Here, it is preferable that the width _{l 4} of the out-heater 150 is formed by 10～17Mm. Then, by making the distance l ₂ closer to the silicon wafer 101 to such an extent that the distance l ₂ is shorter than the width dimension l _{4 of the} outheater 150, it is possible to easily transfer the necessary amount of heat to the silicon wafer 101 through the holder 110. Can do. Here, it is preferable to arrange the distance l ₂ to be about 6 mm.

Further, the in-heater 160 is disposed further away from the out-heater 150 on the back side of the holder 110. Here, the in-heater 160 is arranged so that the distance l ₃ from the back surface of the out-heater 150 to the front surface of the in-heater 160 is longer than the distance l ₁ from the back surface of the holder 110 to the surface of the out-heater 150 described above. In particular, it is preferable that the distance l ₃ from the back surface of the outheater 150 to the surface of the inheater 160 is 7 times or more than the distance l ₁ from the back surface of the holder 110 to the surface of the outheater 150. Here, it is preferable to arrange the distance l _{3 to} be 10.5 to 14.5 mm. In such a case, it is preferable that the distance l ₅ from the back surface of the silicon wafer 101 to the surface of the in-heater 160 is 14.5 to 18.5 mm. Compared to the conventional case, by separating the outheater 150 and the inheater 160, it is possible to prevent the inheater 160 itself from being heated by the outheater 150. In particular, it is possible to prevent the edge portion of the silicon wafer 101 from being heated more than necessary because the vicinity of the outer periphery of the inheater 160 overlapping the outheater 150 is heated by the outheater 150.

FIG. 5 is a diagram showing a simulation result of the temperature distribution in the wafer surface in which the first embodiment is compared with the conventional configuration.
In FIG. 5, it can be seen that in the conventional heater arrangement (layout), the temperature has greatly increased near the wafer edge (near 90 mm from the wafer center). In this case, even if the film thickness shortage near the wafer edge due to the so-called edge effect is resolved, the film thickness near the wafer edge becomes too large and the variation in the film thickness at the center of the wafer becomes large. On the other hand, according to the configuration of the first embodiment, the temperature rise near the wafer edge (near 90 mm from the center of the wafer) is small, and it can be seen that the uniformity within the wafer surface is greatly improved as compared with the prior art.

FIG. 6 is a diagram showing a temperature difference in the wafer surface and a heater MAX temperature comparing Embodiment 1 with the conventional configuration.
As shown in FIG. 6, it can be seen that according to the first embodiment, the temperature difference in the wafer surface is smaller than in the conventional configuration. Therefore, it can be seen that the in-plane uniformity of the wafer is greatly improved as compared with the prior art. Further, the maximum (MAX) temperature of the outheater 150 and the inheater 160 can be reduced, and the load on the heater can be reduced. As a result, the life of the heater is also improved.

  As described above, according to the present embodiment, the in-plane temperature distribution of the silicon wafer 101 can be kept uniform. Therefore, the so-called edge effect can be suppressed and the film thickness uniformity of the silicon wafer 101 can be improved.

  With this configuration, it is possible to perform epitaxial growth of 60 μm or more, which is an n-base thickness excellent in film thickness uniformity.

  Of course, not only IGBTs, but also power semiconductors that require high breakdown voltage, power MOSs, GTOs (gate turn-off thyristors) and general thyristors (SCRs) that are used as switching elements for trains and the like. It can be applied to the formation of an epitaxial layer with a thick base.

  The embodiments have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. For example, although an epitaxial growth apparatus has been described as an example of a vapor phase growth apparatus, the present invention is not limited to this, and any apparatus for vapor phase growth of a predetermined film on a sample surface may be used. For example, an apparatus for growing a polysilicon film may be used.

  In addition, although descriptions are omitted for parts and the like that are not directly required for the description of the present invention, such as a device configuration and a control method, a required device configuration and a control method can be appropriately selected and used. For example, although the description of the control unit configuration for controlling the epitaxial growth apparatus 100 is omitted, it goes without saying that the required control unit configuration is 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.

1 is a conceptual diagram showing a configuration of an epitaxial growth apparatus in a first embodiment. It is a figure which shows an example of the external appearance of an epitaxial growth apparatus system. It is a figure which shows an example of a unit structure of an epitaxial growth apparatus system. FIG. 3 is a conceptual cross-sectional view for explaining details of a holder shape and a heater layout in the first embodiment. It is a figure which shows the simulation result of the wafer surface temperature distribution which compared Embodiment 1 and the conventional structure. It is a figure which shows the wafer surface temperature difference and heater MAX temperature which compared Embodiment 1 and the conventional structure. It is a conceptual diagram which shows the shape and arrangement configuration of the conventional holder and heater. It is a figure which shows an example of the dimension of the arrangement structure shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Epitaxial growth apparatus 101,200 Silicon wafer 110,210 Holder 112 Convex part 116 Counterbore hole 120 Chamber 122,124 Flow path 130 Shower head 140 Vacuum pump 142 Pressure control valve 150,151 Out heater 160,161 In heater 170,171 Rotating member 300 Epitaxial growth system 310, 312 Cassette stage 320 L / L chamber 330 Transfer chamber 332, 350 Transfer robot

Claims (5)

In a vapor phase growth apparatus for forming a film on a substrate using the gas in a chamber connected to a first flow path for supplying gas and a second flow path for exhausting gas,
A support having a ring-shaped convex portion on the back surface and supporting the substrate on the front surface side;
A first heat source disposed on the back side of the support base and on the outer side of the outer peripheral end of the convex part such that the surface position is located on the support base side with respect to the tip of the convex part;
A second heat source disposed further away from the first heat source on the back side of the support base;
A vapor phase growth apparatus comprising:   The first heat source is formed in an annular shape, and the distance from the inner peripheral end of the first heat source to the outer peripheral end of the substrate is such that the outer peripheral end of the first heat source is the inner peripheral end of the first heat source. The vapor phase growth apparatus according to claim 1, wherein the vapor phase growth apparatus is disposed so as to be shorter than a length in a radial direction. The support base is formed in an annular shape,
The first heat source has a radial length from the outer peripheral end of the first heat source to the inner peripheral end of the first heat source, and a radius from the outer peripheral end of the support base to the inner peripheral end of the support base. 3. The vapor phase growth apparatus according to claim 2, wherein the vapor phase growth apparatus is formed so as to be 45 to 59% of a length in a direction.   The first and second heat sources so that the distance from the back surface of the first heat source to the surface of the second heat source is longer than the distance from the back surface of the support base to the surface of the first heat source. The vapor phase growth apparatus according to any one of claims 1 to 3, wherein:   The first and second distances are such that the distance from the back surface of the first heat source to the surface of the second heat source is at least 7 times the distance from the back surface of the support base to the surface of the first heat source. The vapor phase growth apparatus according to claim 4, wherein a heat source is provided.

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