JP2010114139A - Susceptor device, apparatus for manufacturing epitaxial wafer, and method of manufacturing epitaxial wafer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for manufacturing an epitaxial wafer capable of reducing variations in the film thickness of an epitaxial film without causing any abnormal growth on the backside of the epitaxial wafer. <P>SOLUTION: In the manufacturing apparatus 1 for manufacturing the epitaxial wafer WE with a wafer W being mounted substantially concentrically with a susceptor 31, a center rod 33 having an upper end in a semispherical, nearly columnar shape is provided to extend in a vertical direction at a side of a non-mounting surface 312 of the susceptor 31 so that its upper end is in point contact with the center of the susceptor 31. As a result, heat of the point contact section is absorbed by the center rod 33 to reduce its temperature. Also, heat absorption operation by the contact can be reduced as compared with face contact of both of them, thus preventing a local temperature decrease at the center of the susceptor 31. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a susceptor device, an epitaxial wafer manufacturing apparatus, and an epitaxial wafer manufacturing method.

Conventionally, a method of manufacturing an epitaxial wafer by vapor-phase growth of an epitaxial film on the surface of the wafer is known (see, for example, Patent Document 1).
This Patent Document 1 discloses a configuration in which a susceptor is supported at three points from the back side by a quartz support shaft. Above and below the susceptor supported by the support shaft, there is provided a heating device that is composed of a halogen lamp or the like and heats the susceptor and the wafer with radiant heat.

JP 2000-269137 A

However, in the configuration of Patent Document 1, since only the peripheral edge of the non-mounting surface of the susceptor is supported by the support shaft, the radiation light from the front, rear, left and right heating devices concentrates on the center of the non-mounting surface of the susceptor. The temperature of the portion corresponding to the center of the epitaxial wafer (meaning only one point at the center) and the vicinity thereof (hereinafter referred to as the susceptor center-corresponding portion) will be higher than the surrounding portions. As a result, the thickness of the epitaxial film at the center of the epitaxial wafer (hereinafter referred to as the epi-center thickness as appropriate) becomes extremely thick compared to the surrounding portion. In other words, the film thickness variation (hereinafter referred to as the center) of the central portion of the epitaxial wafer (meaning a substantially circular portion having a diameter of about A / 2 centered on the center of the epitaxial wafer when the diameter of the epitaxial wafer is A). (Referred to as part thickness variation).
In order to reduce such film thickness variation in the central portion, it is conceivable to greatly reduce the amount of reaction gas used for vapor phase growth of the epitaxial film.
However, if the amount of the reaction gas is greatly reduced, the film thickness variation in the central portion is improved, but abnormal growth occurs on the back surface of the epitaxial wafer, and there is a problem that the nanotopography is deteriorated.

  An object of the present invention is to provide a susceptor device, an epitaxial wafer manufacturing apparatus, and an epitaxial wafer manufacturing method capable of reducing variations in the thickness of an epitaxial film without causing abnormal growth on the back surface of the epitaxial wafer. .

  The susceptor apparatus of the present invention is provided in an epitaxial wafer manufacturing apparatus for manufacturing an epitaxial wafer by vapor-phase growing an epitaxial film on a film forming surface of the wafer while irradiating the wafer with radiation light and heating the wafer. A susceptor device for holding the wafer, the susceptor having a mounting surface on which the wafer is mounted, peripheral support means for supporting the vicinity of the peripheral edge of the susceptor, and when the wafer is mounted Temperature control means for controlling the temperature of a portion of the susceptor corresponding to the center of the wafer, and the temperature control means is formed in a substantially rod shape or a substantially plate shape, and is not placed opposite to the placement surface. It extends in a direction substantially orthogonal to the non-mounting surface on the surface side, and the end on the non-mounting surface side is substantially point contact or substantially pointed with a portion corresponding to the center of the wafer on the non-mounting surface Characterized in that provided in a state of contact.

Here, the approximate point contact and the approximate line contact mean that the contact area between the temperature control means and the susceptor is extremely small compared to the area of the wafer, and the contact area is appropriately set depending on the material and thickness of the susceptor. The The contact area is preferably 0.05% or less of the area of the wafer, for example.
By the way, when the non-mounting surface of the susceptor is brought into surface contact with the end portion of the temperature control means, the portion in contact with the surface is absorbed by the temperature control means and is locally lower than the other portions. turn into. For this reason, there exists a possibility that epi center film thickness may become thin locally compared with the circumference | surroundings.
On the other hand, in the present invention, since the end of the temperature control means is substantially point contact or substantially line contact with the susceptor center corresponding part of the non-mounting surface, compared with the configuration in which both are in surface contact, The endothermic action of the susceptor center-corresponding portion can be reduced, and the temperature of the susceptor center-corresponding portion can be lowered without causing a local temperature drop.
Therefore, the temperature of the susceptor center-corresponding portion can be appropriately reduced, and an epitaxial film having a small thickness variation in the center portion can be vapor-phase grown without greatly reducing the amount of the reaction gas. In addition, since it is not necessary to reduce the reaction gas in order to reduce the film thickness variation in the central portion, it is possible to prevent abnormal growth from occurring on the back surface of the epitaxial wafer.
When the center of the susceptor coincides with the center of the wafer placed on the susceptor, the susceptor center corresponding portion is a portion centered on the center of the susceptor. For this reason, the temperature control means is provided in a state where the end thereof is in substantially point contact or substantially line contact with the center of the non-mounting surface. Further, when the center of the susceptor and the center of the wafer placed on the susceptor do not coincide with each other, the susceptor center-corresponding portion is a portion centered on a position shifted from the center of the susceptor. For this reason, the temperature control means is provided in a state in which the end thereof is in substantially point contact or substantially line contact at a position shifted from the center of the non-mounting surface.

In the susceptor device of the present invention, the end portion on the non-mounting surface side of the temperature control means is formed in a cone shape or a hemispherical shape, and is provided in a state of being substantially in point contact with the non-mounting surface. A configuration is preferred.
According to this invention, the temperature control means and the non-mounting surface can be brought into substantially point contact without fine installation adjustment by forming the end of the temperature control means in the shape of a cone or a hemisphere.

In the susceptor device of the present invention, it is preferable that the temperature control means is detachably attached to the peripheral edge support means.
According to this invention, since the temperature control means is detachably attached to the peripheral support means, the temperature control means is etched with the corrosive gas, and the temperature is changed before the contact area changes with the change in length or thickness. The control means can be exchanged. Therefore, by replacing the temperature control means as necessary, the endothermic effect can be made substantially constant, and an epitaxial wafer with stable quality can be manufactured.

An epitaxial wafer manufacturing apparatus of the present invention is an epitaxial wafer manufacturing apparatus for manufacturing an epitaxial wafer by vapor-phase-growing an epitaxial film on a film formation surface of the wafer, and the above-described susceptor apparatus for holding the wafer; This susceptor device is installed inside, and a reaction vessel capable of supplying a reaction gas for vapor-phase growth of an epitaxial film on the film formation surface of the wafer, and irradiation with radiation light toward the wafer And a light emission heating means for heating the wafer.
Here, as the light emitting and heating means, one that irradiates radiation light from at least one of the film forming surface side of the wafer and the back surface side opposite to the film forming surface can be applied.

  In the epitaxial wafer manufacturing method of the present invention, the wafer is held by a susceptor device that holds the wafer, and the wafer is irradiated with radiation light to supply the reaction gas to the wafer while heating the wafer. An epitaxial wafer manufacturing method for manufacturing an epitaxial wafer by vapor-phase-growing an epitaxial film on a film forming surface, wherein the susceptor device includes a susceptor having a mounting surface on which the wafer is mounted, and the susceptor Peripheral support means for supporting the vicinity of the peripheral edge, and temperature control means for controlling the temperature of the portion of the susceptor corresponding to the center of the wafer when the wafer is placed, the temperature control means being substantially rod-shaped. Alternatively, it is formed in a substantially plate shape and extends in a direction substantially orthogonal to the non-mounting surface on the non-mounting surface side opposite to the mounting surface, and the non-mounting surface The surface side end is provided in a state of substantially point contact or substantially line contact with a portion corresponding to the center of the wafer on the non-mounting surface, and heat of a portion corresponding to the center of the wafer on the non-mounting surface. Is absorbed by the temperature control means to control the temperature of the portion of the susceptor corresponding to the center of the wafer.

  According to the above invention, by providing the manufacturing apparatus with the same configuration as the susceptor apparatus described above, the epitaxial wafer manufacturing apparatus and manufacturing that can reduce the film thickness variation in the central portion without causing abnormal growth on the back surface of the epitaxial wafer. Can provide a method.

An embodiment of the present invention will be described with reference to the drawings.
[Configuration of epitaxial wafer manufacturing equipment]
First, the configuration of an epitaxial wafer manufacturing apparatus will be described.
FIG. 1 is a cross-sectional view showing a main part of an epitaxial wafer manufacturing apparatus. FIG. 2 is a plan view of the epitaxial wafer manufacturing apparatus.
As shown in FIG. 1, the epitaxial wafer manufacturing apparatus 1 manufactures an epitaxial wafer WE by vapor-phase-growing an epitaxial film E on a film-forming surface W1 of a wafer W obtained by processing a semiconductor crystal into a plate shape. As shown in FIGS. 1 and 2, the manufacturing apparatus 1 includes a reaction vessel 2, a susceptor device 3, and a heating unit 4.

The reaction vessel 2 has a susceptor device 3 installed therein, and is configured to be able to supply reaction gas and purge gas therein. Then, by supplying the reaction gas to the wafer W placed on the susceptor device 3, the epitaxial film E is vapor-phase grown on the film formation surface W <b> 1 of the wafer W. The reaction vessel 2 includes an upper chamber member 21 and a lower chamber member 22.
Although not shown in detail, the upper chamber member 21 and the lower chamber member 22 are formed in a substantially concave shape in which a central portion in a plan view is depressed by combining a plurality of translucent members such as quartz. Then, the reaction chamber 2A is formed inside the reaction vessel 2 by detachably fixing the upper chamber member 21 so that the substantially concave opening faces downward and the opening of the lower chamber member 22 faces upward. Is done.
A preheating ring 23 is attached to the inner peripheral surface on the upper end side of the lower chamber member 22. The inner diameter dimension of the preheating ring 23 is set larger than the outer diameter dimension of a susceptor 31 described later.

On the side surface of the reaction vessel 2, a reaction gas supply pipe and a reaction gas discharge pipe (not shown) for flowing the reaction gas in a substantially horizontal direction on the film formation surface W <b> 1 of the wafer W are provided. Further, a purge gas supply pipe and a purge gas discharge pipe (not shown) are provided on the side surface of the reaction vessel 2 for flowing the purge gas in a direction substantially equal to the reaction gas below the susceptor 31.
Here, as the reaction gas, a material gas mixed with a carrier gas in addition to a source gas for vapor-phase growth of the epitaxial film E can be employed. As the source gas, a gas corresponding to the epitaxial film E to be vapor-phase grown may be employed. For example, a mixed reaction gas obtained by diluting SiHCl _{3 as} a silicon source and boron dopant source B ₂ H ₆ with hydrogen gas can be employed. . As the carrier gas, for example, a gas containing hydrogen (carrier hydrogen) can be adopted.
Furthermore, various types of purge gas can be employed, such as hydrogen gas (slit hydrogen).

The susceptor device 3 holds a wafer W having a diameter of 200 mm or 300 mm and is installed inside the reaction vessel 2. The susceptor device 3 includes a susceptor 31, a peripheral edge support means 32, and a center rod 33 as a temperature control means.
The susceptor 31 is formed in a substantially disk shape in plan view. One surface of the susceptor 31 is a mounting surface 311 on which the wafer W is mounted. A concave portion (not shown) having a circular shape in plan view corresponding to the outer shape of the wafer W is formed at the center of the mounting surface 311, and the center of the susceptor 31 and the center of the wafer W substantially coincide with each other in the concave portion. The wafer W is installed in the state.
The peripheral support means 32 is made of a translucent member such as quartz, protrudes from the central portion of the lower chamber member 22 of the reaction vessel 2 into the reaction chamber 2A, and installs the susceptor 31 in the reaction vessel 2 in a horizontal state. The wafer W is placed on the susceptor 31. The peripheral edge support means 32 is configured to be rotatable about the rotation axis R. The peripheral support means 32 includes a support main body 321 projecting into the reaction chamber 2A from the central portion of the lower chamber member 22, and three peripheral support lots 322 extending obliquely upward from the upper end of the support main body 321. It is equipped with.
The peripheral support lots 322 are provided at intervals of about 120 ° in plan view. The susceptor 31 is installed horizontally in the reaction chamber 2A by supporting the vicinity of the periphery of the non-mounting surface 312 of the susceptor 31 at three points by the tip portions of the three peripheral support lots 322. The
Note that three or more peripheral support lots 322 may be provided, or a substantially conical cylindrical member extending radially from the upper end of the support body 321 may be provided instead of the peripheral support lot 322.

  Moreover, the upper end surface of the support main body part 321 is provided with a rod fitting recess 321A into which the lower end of the center rod 33 is detachably fitted. The center rod 33 is formed in a substantially cylindrical shape with a hemispherical tip by a transparent member such as quartz, and the lower end of the center rod 33 is fitted into the rod fitting recess 321 </ b> A, so that the non-mounting surface 312 side of the susceptor 31. In FIG. 2, it is installed so as to extend in a direction (vertical direction) substantially orthogonal to the non-mounting surface 312. The surface of the center rod 33 is roughened by sandblasting. Here, the length dimension of the center rod 33 is set such that the upper end of the center rod 33 and the center of the non-mounting surface 312 are in point contact. The diameter of the portion of the center rod 33 that is not fitted in the rod fitting recess 321A is set to 3.0 mm or more and 22.0 mm or less. Here, the diameter of the center rod 33 can be set to a size corresponding to the diameter of the wafer W. That is, the diameter of the center rod 33 can be exemplified as 4.7 mm when the diameter of the wafer W is 200 mm and 20.5 mm when the diameter of the wafer W is 300 mm.

The heating unit 4 includes a plurality of front side light emitting and heating means 41 provided above the reaction vessel 2 and a plurality of back side light emitting and heating means 42 provided below the reaction vessel 2. The back side light emission heating means 42 is arranged in a ring shape substantially concentric with the susceptor 31, and irradiates radiation light from below the reaction vessel 2 to heat the wafer W and the susceptor 31. Although not shown here, the front surface side light emitting and heating means 41 is arranged in a ring shape substantially concentric with the susceptor 31 similarly to the back surface side light emitting and heating means 42, and the wafer W and the susceptor 31 from above the reaction vessel 2. Heat.
For example, a halogen lamp or an infrared lamp can be used as the front side light emitting and heating means 41 and the back side light emitting and heating means 42.
The heating unit 4 includes an in-front reflection unit 43, a back-inside reflection unit 44, an out-of-surface reflection unit 45, and a back-outside reflection unit 46, each formed in a substantially cylindrical shape. The front reflection part 43 and the back reflection part 44 are provided so as to protrude in a direction approaching the susceptor 31 from a substantially ring-shaped internal space constituted by the front side light emission heating means 41 and the back side light emission heating means 42. . The outer reflection part 45 and the outer reflection part 46 are provided so as to surround the above-described protruding portions of the inner reflection part 43 and the inner reflection part 44. The radiant light emitted from the surface-side light emitting and heating means 41 passes between the inner reflection part 43 and the outer reflection part 45 and is reflected by these to irradiate the wafer W. Further, the radiation light emitted from the back side light emitting and heating means 42 passes between the back inner reflection portion 44 and the back outer reflection portion 46 and is reflected by these to irradiate the non-mounting surface 312 of the susceptor 31. Is done.

[Method of manufacturing epitaxial wafer]
Next, a method for manufacturing the epitaxial wafer WE using the manufacturing apparatus 1 described above will be described.
First, the front surface side light emitting and heating means 41 and the back surface side light emitting and heating means 42 are driven to heat the susceptor 31 on which the wafer W is placed to a desired growth temperature.
Then, as shown below, the epitaxial film E is vapor-phase grown on the film formation surface W1 of the wafer W while rotating the peripheral support means 32 around the rotation axis R.
Specifically, first, vapor phase etching is performed by flowing, for example, hydrogen chloride gas, which is a corrosive gas, onto the film formation surface W1 of the wafer W immediately before the vapor phase growth, and natural oxidation of the film formation surface W1 is performed. Remove the membrane. Thereafter, a reaction gas is always supplied horizontally on the film formation surface W1 of the wafer W, and a purge gas is introduced below the susceptor 31 at a predetermined timing.
That is, by controlling the flow rate of the reactive gas and the flow rate of the purge gas, a reactive gas flow is formed in which the reactive gas flows through the upper side of the wafer W during the vapor phase growth of the epitaxial film E, and the purge gas flows below the susceptor 31. A flowing purge gas stream is formed. By performing vapor phase growth in this way, an epitaxial film E is formed on the surface of the wafer W, and an epitaxial wafer WE is manufactured.

By the way, the back surface side light emission heating means 42 is arranged in a substantially ring shape. For this reason, when the center rod 33 is not provided, the irradiation amount of the radiant light from the back surface side light emitting and heating means 42 in the susceptor 31 is larger in the center than in the peripheral side, and the temperature of the susceptor 31 is in the center than in the peripheral side Is higher.
On the other hand, since the manufacturing apparatus 1 is provided with a center rod 33 that makes point contact with the center of the susceptor 31, the point contact portion is absorbed by the center rod 33 and the temperature is lowered. In addition, when the two are brought into surface contact, for example, compared to the case where the contact area exceeds 0.05% of the area of the wafer, the endothermic effect due to contact can be reduced, and the local temperature drop at the center of the susceptor 31 can be reduced. There is no invitation.
From the above, the susceptor 31 is heated to a state in which the temperature at the center is appropriately lowered as compared with the configuration in which the center rod 33 is not provided. Therefore, the epitaxial film E having a small thickness variation in the central portion can be vapor-phase grown without greatly reducing the amount of the reaction gas.

[Effects of Embodiment]
In the embodiment as described above, the following operational effects can be obtained.
(1) With the manufacturing apparatus 1, the center rod 33 extends in the vertical direction on the non-mounting surface 312 side of the susceptor 31 and the upper end is in point contact with the center of the susceptor 31 (susceptor center corresponding portion). Provided.
For this reason, as described above, it is possible to reduce the thickness variation in the central portion without greatly reducing the amount of the reaction gas, and it is possible to prevent abnormal growth from occurring on the back surface of the epitaxial wafer WE.

  (2) Since the upper end of the center rod 33 is formed in a hemispherical shape, the center rod 33 and the susceptor 31 can be brought into point contact without adjustment for fine installation.

  (3) Since the center rod 33 is detachably provided on the support body 321 of the peripheral support means 32, the center rod 33 is replaced before the center rod 33 is etched with hydrogen chloride gas and the contact area changes. Thus, the endothermic action can be made substantially constant, and a stable quality epitaxial wafer WE can be manufactured.

[Other Embodiments]
Note that the present invention is not limited to the above embodiment, and various improvements and design changes can be made without departing from the scope of the present invention.

That is, as shown in FIG. 3, a substantially rod-shaped center rod 33 </ b> A whose upper end is formed in a conical shape may be provided in point contact with the susceptor 31. Here, the shape of the upper end may be a pyramid shape.
As shown in FIG. 4, a substantially rod-shaped center rod 33B having a cylindrical portion 33B1 and a spherical portion 33B2 provided at the distal end of the cylindrical portion 33B1 is applied, and the distal end 33B3 of the spherical portion 33B2 is used as the susceptor 31. You may make point contact.
Then, as shown in FIG. 5, a center rod 33 </ b> C formed in a conical shape as a substantially rod shape may be applied to bring the tip 33 </ b> C <b> 3 into point contact with the susceptor 31.
Furthermore, as shown in FIG. 6, a center rod 33 </ b> D whose longitudinal section is formed in a substantially wall shape may be applied to bring the tip 33 </ b> D <b> 3 into line contact with the susceptor 31.
Further, a substantially rod-shaped temperature control member having an upper end formed in a circular arc shape may be provided in line contact with the susceptor 31.
The center rod 33 formed of a transparent member such as quartz may not be sandblasted, or the center rod 33 may be formed of an opaque member such as opaque quartz or SiC (silicon carbide). The center rod 33 and the peripheral support means 32 may be integrally formed so that the center rod 33 cannot be detached from the peripheral support means 32.
Further, when the film is formed in a state where the center of the susceptor 31 and the center of the wafer W placed on the susceptor 31 do not coincide with each other, the upper end of the center rod 33 is not the center of the non-mounting surface 312. By providing a substantially point contact or a substantially line contact at a position corresponding to the center of the wafer W shifted from the center of the non-mounting surface 312, it is possible to obtain the same effect as the above embodiment.

  The present invention can be used in a susceptor device, an epitaxial wafer manufacturing apparatus, and an epitaxial wafer manufacturing method.

It is sectional drawing which shows the principal part of the manufacturing apparatus of the epitaxial wafer which concerns on one Embodiment of this invention. It is a top view of the manufacturing apparatus of the epitaxial wafer. It is a side view of the center rod which concerns on the modification of this invention. It is a side view of the center rod which concerns on the further another modification of this invention. It is a side view of the center rod which concerns on the further another modification of this invention. It is a side view of the center rod which concerns on the further another modification of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Manufacturing apparatus 2 ... Reaction container 3 ... Susceptor apparatus 31 ... Susceptor 32 ... Periphery support means 33, 33A, 33B, 33C, 33D ... Center rod as temperature control means 42 ... Back side light emission heating means 311 ... Mounting surface 312 ... non-mounting surface E ... epitaxial film W ... wafer W1 ... deposition surface WE ... epitaxial wafer

Claims (5)

Provided in an epitaxial wafer manufacturing apparatus for manufacturing an epitaxial wafer by vapor-phase growth of an epitaxial film on a film forming surface of the wafer while irradiating the wafer with radiation light and holding the wafer A susceptor device,
A susceptor having a mounting surface on which the wafer is mounted;
Peripheral support means for supporting the vicinity of the periphery of the susceptor;
Temperature control means for controlling the temperature of the portion corresponding to the center of the wafer in the susceptor when the wafer is placed, and
The temperature control means is formed in a substantially rod shape or a substantially plate shape, extends in a direction substantially perpendicular to the non-mounting surface on the non-mounting surface side opposite to the mounting surface, and the non-mounting surface The susceptor device is characterized in that the end on the side is provided in a substantially point contact or substantially line contact with a portion of the non-mounting surface corresponding to the center of the wafer. The susceptor device according to claim 1,
The end portion on the non-mounting surface side in the temperature control means is formed in a cone shape or a hemispherical shape, and is provided in a state of being substantially in point contact with the non-mounting surface. . The susceptor device according to claim 1 or 2,
The susceptor device, wherein the temperature control means is detachably attached to the peripheral edge support means. An epitaxial wafer manufacturing apparatus for manufacturing an epitaxial wafer by vapor-phase growing an epitaxial film on a film forming surface of the wafer,
The susceptor device according to any one of claims 1 to 3, which holds the wafer;
This susceptor device is installed inside, and a reaction vessel capable of supplying a reaction gas for vapor-phase growth of an epitaxial film on the film formation surface of the wafer,
A light emission heating means for heating the wafer by irradiating radiation toward the wafer;
An epitaxial wafer manufacturing apparatus comprising: A susceptor device that holds the wafer holds the wafer, irradiates the wafer with radiation light, heats the wafer, supplies a reactive gas to the wafer, and deposits an epitaxial film on the film formation surface of the wafer. An epitaxial wafer manufacturing method for growing an epitaxial wafer, comprising:
The susceptor device corresponds to a susceptor having a placement surface on which the wafer is placed, peripheral support means for supporting the vicinity of the periphery of the susceptor, and the center of the wafer in the susceptor when the wafer is placed. Temperature control means for controlling the temperature of the portion to be
The temperature control means is formed in a substantially rod shape or a substantially plate shape, extends in a direction substantially perpendicular to the non-mounting surface on the non-mounting surface side opposite to the mounting surface, and the non-mounting surface The end on the side is provided in a state of substantially point contact or substantially line contact with a portion corresponding to the center of the wafer on the non-mounting surface,
The temperature of the portion of the non-mounting surface corresponding to the center of the wafer is absorbed by the temperature control means to control the temperature of the portion of the susceptor corresponding to the center of the wafer. Method.

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