JP2004055595A - Vapor deposition device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vapor deposition device which is simple in structure, superior in controllability, and capable of heating all the surface of a wafer uniformly, when a thin film is formed. <P>SOLUTION: The vapor deposition device is equipped with a deposition chamber, which houses the wafer and carries out vapor deposition on the surface of the wafer as using material gas supplied from outside, a plate-like wafer holder which holds the wafer housed in the deposition chamber on its surface, and a heater which is arranged so as to confront the rear surface of the wafer holder to heat the wafer holder. The wafer holder is equipped with a recessed wafer pocket for receiving the wafer on its surface, and the wafer pocket is equipped with a bottom region which comes, at least partially into surface-contact with the surface of the wafer and a sidewall region which specifies the position of the wafer as coming into contact with the side of the wafer. The bottom region is composed of a center region and a peripheral region, and at least either of the side wall region and peripheral region of the wafer holder is set lower in thermal conductivity than that of the center region of the bottom region. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vapor phase growth apparatus, and more particularly, to a structure of a vapor phase growth apparatus that supplies a source gas for vapor phase growth on a surface of a wafer to form a thin film.
[0002]
[Prior art]
In recent years, demand for semiconductor devices has been increasing. A semiconductor device is manufactured using a semiconductor element obtained by dividing a wafer on which a desired thin film is formed.
As a method for forming a thin film of a semiconductor, an insulator, a metal, or the like on a wafer, there are a CVD (Chemical Vapor Deposition) method, a plasma CVD method, an MOCVD (Metal Organic Chemical Vapor Deposition) method, and the like.
[0003]
In these methods, a source gas for vapor phase growth is supplied onto a wafer, and the source gas is decomposed to form a desired thin film on the wafer. There is a phase growth device.
In a vapor phase growth apparatus, a wafer on which a thin film is to be formed is generally held by a wafer holder.
The wafer holder has a wafer pocket which is a depression for accommodating a wafer on the surface thereof, and the wafer accommodated in the wafer pocket is heated by receiving heat conduction from the wafer holder during the formation of a thin film.
[0004]
Various conventional vapor phase epitaxy apparatuses are known. For example, a wafer is held on a holding member (wafer holder), and the holding member is heated to heat the wafer. There is known a thin film manufacturing apparatus for forming a thin film thereon, which has a temperature control means provided at the periphery of the wafer of the holding member to reduce the temperature of the periphery of the wafer of the holding member (for example, See JP-A-7-249580).
[0005]
[Problems to be solved by the invention]
Since the electrical properties of a semiconductor vary greatly depending on the very small amount of impurities in the semiconductor, such as ppb and ppm, it is necessary to precisely control the absolute amount or the distribution of these small amounts of impurities.
For example, when a semiconductor thin film is formed on a wafer and an impurity element is incorporated into the thin film at the same time, the amount of the incorporated impurity element largely depends on the temperature of the wafer surface.
Further, even when impurities are thermally diffused, the amount of diffusion greatly depends on the absolute temperature of the wafer.
[0006]
Further, in order to improve the yield of a plurality of semiconductor elements obtained from one wafer, it is necessary to form a thin film having uniform characteristics over the entire surface of the wafer.
For this reason, the wafer holder holding the wafer is often rotated in the vapor phase growth apparatus during the formation of the thin film.
At this time, the side surface of the wafer accommodated in the wafer pocket contacts the wall surface of the wafer pocket due to centrifugal force.
As a result, the outer peripheral portion of the wafer receives heat conduction from both the bottom and side surfaces of the wafer pocket, and the outer peripheral portion of the wafer has a higher temperature than the central portion.
[0007]
For example, when a wafer holder made of molybdenum and having a diameter of about 200 mm is used and heated so that the temperature of the wafer becomes about 750 ° C., the outer peripheral portion about 5 mm from the outer edge of the wafer has a temperature about 5 mm higher than the central part. About 5 ° C higher.
In this case, as described above, the characteristics of the thin film formed in the plane of the wafer become non-uniform, and as a result, the yield of a plurality of semiconductor elements obtained from one wafer decreases.
[0008]
For this reason, a vapor phase growth apparatus capable of heating the entire surface of the wafer to a uniform temperature has been demanded. However, as a matter of course, the configuration as the apparatus is simple and excellent in operability such as setting a wafer to the apparatus. Is desired.
The present invention has been made in view of the above circumstances, and has a simple configuration and excellent operability, but is capable of heating the entire surface of a wafer to a uniform temperature when forming a thin film. Is provided.
[0009]
[Means for Solving the Problems]
The present invention is directed to a growth chamber for accommodating a wafer and performing vapor phase growth on a wafer surface by using a supplied source gas, a plate-shaped wafer holder accommodated in the growth chamber and holding the wafer on the surface, and a back surface of the wafer holder. A wafer holder for heating the wafer holder, the wafer holder having a recessed wafer pocket on its surface for receiving the wafer, wherein the wafer pocket has a bottom surface area at least partially in contact with the surface of the wafer; And a side wall region defining the position of the wafer in contact with the side surface of the wafer, the bottom surface region includes a central region and an outer peripheral region, and at least one of the side wall region and the outer peripheral region of the wafer holder has a thermal conductivity higher than that of the central region. A vapor phase growth apparatus characterized in that it is also configured to have a low temperature.
[0010]
That is, in the vapor phase growth apparatus according to the present invention, the wafer pocket has a side wall region and a bottom surface region, and the bottom surface region includes a central region and an outer peripheral region.
The thermal conductivity of at least one of the side wall region and the outer peripheral region is set lower than that of the central region.
For this reason, when the wafer accommodated in the wafer pocket is heated by receiving heat conduction from the wafer holder, the thermal conductivity with respect to the outer peripheral portion of the wafer, which is likely to be higher than the set temperature, becomes lower than the central portion, and as a result, The entire surface of the wafer can be heated uniformly.
Further, in order to achieve such an effect, it is not necessary to interpose a separate member between the wafer holder and the wafer, so that the configuration of the apparatus is very simple, and operability such as setting of a wafer is reduced. Are better.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
A vapor phase growth apparatus according to the present invention includes: a growth chamber for performing vapor phase growth on a wafer surface by using a source gas that accommodates and supplies a wafer; a plate-shaped wafer holder that is accommodated in the growth chamber and holds the wafer on the surface; The wafer holder is provided with a heater arranged to face the back surface of the wafer holder to heat the wafer holder. The wafer holder has a recessed wafer pocket for receiving a wafer on its surface, and the wafer pocket has at least a part of the surface of the wafer. It has a bottom surface area that is in surface contact and a side wall area that contacts the side surface of the wafer and defines the position of the wafer. The bottom area includes a central area and an outer peripheral area, and at least one of the side wall area and the outer peripheral area of the wafer holder has heat conduction. The rate is lower than that of the central area.
[0012]
In the vapor phase growth apparatus according to the present invention, the outer peripheral region of the bottom region may be recessed from the central region.
According to such a configuration, a gap is formed between the bottom surface region and the outer peripheral portion of the wafer. As a result, heat conduction from the outer peripheral region to the outer peripheral portion of the wafer is suppressed to a low level.
Further, since the suppression of the thermal conductivity with respect to the outer peripheral portion of the wafer is caused by the shape of the wafer pocket, the wafer holder can be made of a single component material, and the configuration as an apparatus is further simplified.
[0013]
Further, in the vapor phase growth apparatus according to the present invention, the wafer holder has a central region made of the first material and a peripheral region made of the second material having a lower thermal conductivity than the first material. Is also good.
Further, in the vapor phase growth apparatus according to the present invention, the wafer holder has a portion serving as a bottom surface region made of a first material, and a portion serving as a side wall region made of a second material having a lower thermal conductivity than the first material. Is also good.
In these configurations, the first material may be carbon and the second material may be silicon carbide.
In these configurations, the wafer holder is formed using two materials having different thermal conductivities. However, since the wafer holder is integrated, the configuration of the apparatus is not complicated.
[0014]
Further, in the vapor phase growth apparatus according to the present invention, the source gas may include an organometallic compound.
[0015]
【Example】
Hereinafter, a vapor phase growth apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings. In the following embodiments, common members will be described using the same reference numerals.
[0016]
Example 1
FIG. 1 is an explanatory view schematically showing a configuration of a vapor phase growth apparatus according to Embodiment 1 of the present invention, and FIG. 2 is a cross-sectional view of a wafer holder used in the vapor phase growth apparatus according to Embodiment 1.
[0017]
As shown in FIGS. 1 and 2, a vapor phase growth apparatus 100 according to the first embodiment includes a growth chamber 10 for performing vapor phase growth on a surface of a wafer 2 by using a raw material gas that accommodates and supplies the wafer 2, and a growth chamber 10. The wafer holder 1 includes a plate-shaped wafer holder 1 accommodated in the wafer holder 10 and holding the wafer 2 on its front surface, and a heater 14 arranged to face the back surface of the wafer holder 1 and heating the wafer holder 1. Has a recessed wafer pocket 3 on its surface for receiving the wafer 2, and the wafer pocket 3 contacts the side surface of the wafer 2 to define the position of the wafer 2 by contacting the bottom surface area 4 at least partially in surface contact with the surface of the wafer 2. The bottom region 4 includes a central region 4a and an outer peripheral region 4b. At least one of the side wall region 5 and the outer peripheral region 4b of the wafer holder 1 has a heat conductivity in the central region. And it is configured to be lower than a.
[0018]
A supply port 11 for supplying a source gas or a carrier gas into the growth chamber 10 is provided at an upper portion of the growth chamber 10, and an exhaust gas containing an unreacted gas in the growth chamber 10 is provided at a lower portion of the growth chamber 10. An exhaust port 12 for discharging is provided.
A rotating shaft 13 for rotating the wafer holder 1 at the time of forming a thin film is provided at a lower portion of the growth chamber 10, and the wafer holder 1 is detachably connected via a flat connection portion 13a provided at the tip. .
[0019]
A heater 14 is provided on the back side of the wafer holder 1 connected to the connection portion 13a of the rotating shaft 13 so as to heat the back side of the wafer holder 1 when forming a thin film.
After the thin film is formed, a take-out chamber 15 adjacent to the growth chamber 10 is provided via a gate valve 16 in order to carry the wafer holder 1 out of the growth chamber 10.
[0020]
As shown in FIG. 2, the outer peripheral region 4b of the wafer pocket 3 of the wafer holder 1 according to the first embodiment is recessed from the central region 4a. Is formed between them.
Therefore, when the wafer 2 is heated by the heat conduction from the wafer holder 1, the outer peripheral portion of the wafer 2 receives heat conduction only from the side wall region 5 of the wafer pocket 3, and the heat conduction from the outer peripheral region 4b is greatly reduced. Is done.
As a result, the heat conduction to the central portion of the wafer 2 and the heat conduction to the outer peripheral portion of the wafer 2 are substantially in a state of equilibrium, and the entire surface of the wafer 2 is heated to a uniform temperature. A thin film is formed.
The entire wafer holder 1 according to the first embodiment is made of carbon (graphite) or molybdenum.
[0021]
Example 2
FIG. 3 is a sectional view showing a wafer holder used in a vapor phase growth apparatus according to Embodiment 2 of the present invention. The vapor phase growth apparatus according to the second embodiment is obtained by changing the wafer holder 1 (see FIG. 2) of the vapor phase growth apparatus 100 (see FIG. 1) according to the first embodiment to a wafer holder 21 shown in FIG. The point has not been changed. Therefore, illustration of the entire vapor phase growth apparatus is omitted.
[0022]
As shown in FIG. 3, in the wafer holder 21 according to the second embodiment, only the portion that becomes the outer peripheral region 24 b of the bottom region 24 is formed of silicon carbide (β-Sic) having low thermal conductivity, and the other portions are formed of carbon. (Graphite).
Specifically, a ring 26 made of silicon carbide (β-Sic) is integrally fitted into a portion of the bottom surface region 24 to be the outer peripheral region 24b.
The thermal conductivity of carbon (graphite) is about 128 W / (m · K), and the thermal conductivity of silicon carbide is 42 mW / (m · K).
For this reason, the thermal conductivity from the outer peripheral region 24b to the outer peripheral portion of the wafer 2 is suppressed to be low, and as a result, the heat conduction to the central portion of the wafer 2 and the thermal conduction to the outer peripheral portion of the wafer 2 are substantially balanced.
Therefore, the entire surface of the wafer 2 is heated to a uniform temperature, and a thin film having uniform characteristics is formed on the entire surface of the wafer 2.
[0023]
Example 3
FIG. 4 is a sectional view showing a wafer holder used in a vapor phase growth apparatus according to Embodiment 3 of the present invention. The vapor phase growth apparatus according to the third embodiment is obtained by changing the wafer holder 1 (see FIG. 2) of the vapor phase growth apparatus 100 (see FIG. 1) according to the first embodiment to a wafer holder 31 shown in FIG. The point has not been changed. Therefore, illustration of the entire vapor phase growth apparatus is omitted.
[0024]
As shown in FIG. 4, in the wafer holder 31 according to the third embodiment, only the portion that becomes the sidewall region 35 is formed of silicon carbide (β-Sic) having low thermal conductivity, and the other portions are carbon (graphite). Is formed.
For this reason, the thermal conductivity from the side wall region 35 to the outer peripheral portion of the wafer 2 is suppressed to be low, and as a result, the heat conduction to the central portion of the wafer 2 and the thermal conduction to the outer peripheral portion of the wafer 2 are substantially balanced.
Therefore, the entire surface of the wafer 2 is heated to a uniform temperature, and a thin film having uniform characteristics is formed on the entire surface of the wafer 2.
[0025]
【The invention's effect】
According to the present invention, the wafer pocket has the side wall region and the bottom surface region, the bottom surface region includes the center region and the outer peripheral region, and at least one of the side wall region and the outer peripheral region has a lower thermal conductivity than the central region. Therefore, when the wafer accommodated in the wafer pocket is heated by receiving heat conduction from the wafer holder, the thermal conductivity with respect to the outer peripheral portion of the wafer, which tends to be higher than the set temperature, becomes lower than that of the central portion. Can be uniformly heated.
Furthermore, in order to achieve such an effect, there is no need to interpose a separate member between the wafer holder and the wafer, so that the configuration of the apparatus is very simple, and the operability of setting a wafer and the like is reduced. Are better.
[Brief description of the drawings]
FIG. 1 is an explanatory view schematically showing a configuration of a vapor phase growth apparatus according to Embodiment 1 of the present invention.
FIG. 2 is a sectional view showing a wafer holder used in the vapor phase growth apparatus according to Embodiment 1 of the present invention.
FIG. 3 is a sectional view showing a wafer holder used in a vapor phase growth apparatus according to Embodiment 2 of the present invention.
FIG. 4 is a sectional view showing a wafer holder used in a vapor phase growth apparatus according to Embodiment 3 of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Wafer holder 2 ... Wafer 3 ... Wafer pocket 4 ... Bottom area 4a ... Central area 4b ... Outer peripheral area 5 ... Side wall area 14 ... Heater

Claims (6)

A growth chamber for carrying out vapor phase growth on a wafer surface by a source gas containing and supplying a wafer, a plate-like wafer holder housed in the growth chamber and holding the wafer on the surface, and a back surface of the wafer holder. A wafer holder for heating the wafer holder, the wafer holder having a recessed wafer pocket on its surface for receiving the wafer, the wafer pocket having a bottom surface area at least partially in surface contact with the wafer surface and a side surface of the wafer; Has a side wall region that defines the position of the wafer in contact with the bottom surface region, the bottom region includes a central region and an outer peripheral region, and at least one of the side wall region and the outer peripheral region of the wafer holder has a lower thermal conductivity than the central region. A vapor phase growth apparatus characterized in that: The vapor phase growth apparatus according to claim 1, wherein the bottom surface region is depressed in the outer peripheral region than the central region. 2. The vapor phase growth apparatus according to claim 1, wherein the wafer holder has a central region made of a first material and a peripheral region made of a second material having a lower thermal conductivity than the first material. 2. The vapor phase growth apparatus according to claim 1, wherein a portion serving as a bottom surface region of the wafer holder is made of a first material, and a portion serving as a sidewall region is made of a second material having lower thermal conductivity than the first material. The vapor phase growth apparatus according to claim 3, wherein the first material is carbon, and the second material is silicon carbide. The vapor phase growth apparatus according to any one of claims 1 to 5, wherein the source gas contains an organometallic compound.

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