JP2003257869A - Method for manufacturing silicon wafer and for silicon epitaxial wafer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a silicon wafer capable of making more uniform a film thickness distribution of a silicon thin film (e.g. an epitaxial layer) of a silicon wafer (e.g. a silicon epitaxial wafer). <P>SOLUTION: In a method for manufacturing a silicon wafer, a material gas is supplied to a main surface of a silicon single crystal substrate 2 to carry out a vapor phase growth of a silicon thin film on the main surface. The silicon single crystal substrate 2 arranged in an almost horizontal state is rotated in a plate plane direction, and simultaneously the material gas is supplied almost parallel to the main surface of the silicon single crystal substrate 2 to carry out the vapor phase growth. A course of the material gas is changed during the vapor phase growth. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for manufacturing a silicon wafer and a method for manufacturing a silicon epitaxial wafer.

[0002]

2. Description of the Related Art Conventionally, for example, by supplying a source gas onto the main surface of a silicon single crystal substrate (hereinafter, also simply referred to as a silicon substrate), a silicon epitaxial layer (hereinafter, simply referred to as an epitaxial layer) is formed on the main surface. (Also referred to as a layer) by vapor phase growth to obtain a silicon epitaxial wafer (hereinafter, also simply referred to as an epitaxial wafer).
There is known a method of manufacturing a silicon wafer by vapor-depositing a silicon thin film on the main surface of a silicon substrate, such as manufacturing a silicon wafer. In this vapor phase growth, for example, a silicon substrate is placed on a substantially disk-shaped susceptor with its main surface facing upward, and the silicon substrate is rotated as the susceptor is rotated in the plate surface direction. Also, the source gas is supplied onto the main surface of the silicon substrate while rotating in the plate surface direction.

[0003]

The film thickness of the silicon thin film (eg, epitaxial layer) of the silicon wafer (eg, epitaxial wafer) obtained by vapor phase growth has a correlation with the amount of the source gas supplied. Therefore, conventionally, as described above, in addition to rotating the silicon substrate during the vapor phase growth, by setting the difference in the flow rate of the source gas supplied between the central portion and the peripheral portion of the silicon substrate, There are cases where measures such as adjusting the thickness distribution are taken. However, even if such measures are taken, the film thickness of the silicon thin film may have, for example, an annular distribution.

The present invention has been made in order to solve the above problems, and it is possible to make the film thickness distribution of a silicon thin film (for example, an epitaxial layer) of a silicon wafer (for example, an epitaxial wafer) more uniform. An object of the present invention is to provide a method for manufacturing a silicon wafer and a method for manufacturing a silicon epitaxial wafer.

[0005]

In order to solve the above-mentioned problems, a method of manufacturing a silicon wafer according to the present invention is a method for manufacturing a silicon single crystal substrate while rotating a silicon single crystal substrate arranged in a substantially horizontal state in a plate surface direction. In a method for manufacturing a silicon wafer in which a silicon thin film is vapor-phase grown on a main surface of the substrate by supplying the raw material gas substantially parallel to the main surface of the substrate, the course of the raw material gas is changed during the vapor-phase growth. It is characterized by that. That is, it is characterized in that the course of the source gas during vapor phase growth is changed within a plane parallel to the plate surface of the silicon single crystal substrate.

More specifically, the silicon thin film vapor-deposited on the main surface of the silicon single crystal substrate according to the present invention includes, for example, a silicon epitaxial layer, and in this case, therefore, it is produced by vapor phase epitaxy. The silicon wafer becomes a silicon epitaxial wafer. That is, according to the present invention, a silicon single crystal substrate arranged in a substantially horizontal state is rotated in the plate surface direction, and a source gas is supplied substantially in parallel to the main surface of the silicon single crystal substrate, thereby In a method for manufacturing a silicon epitaxial wafer in which a silicon epitaxial layer is vapor-phase grown on the silicon wafer to manufacture a silicon epitaxial wafer, it is a preferable example to change the course of the source gas during the vapor phase growth. Note that the present invention is not limited to this, and for example, a silicon wafer is manufactured by vapor-depositing a silicon thin film of either a polycrystalline thin film, a nitride, or an oxide on the main surface of a silicon single crystal substrate. You may apply when you do.

The change of the course of the raw material gas can be performed by, for example,
It is preferable to change the rotation speed of the silicon single crystal substrate. Also, in this case, more specifically,
The period of performing the vapor phase growth may be changed so that the period of time during which the rotational speed of the silicon single crystal substrate is different from each other may be changed, or during the period of performing the vapor phase growth,
The rotation speed of the silicon single crystal substrate may be gradually changed. In addition, the change of the course of the raw material gas can also be performed by, for example,
It may be performed by changing the direction of the introduction path of the source gas (for example, constituted by a nozzle) within a plane parallel to the plate surface direction of the silicon single crystal substrate. In addition, the course of the source gas may be changed by moving the susceptor in a direction intersecting the source gas flow in a plane parallel to the plate surface direction of the silicon single crystal substrate, for example. .
In addition, the course of the raw material gas may be changed by changing the carrier gas flow rate, for example. That is, when the carrier gas flow rate is large, the flow velocity of the vapor growth gas containing the carrier gas and the raw material gas is high, and therefore the course of the vapor growth gas is affected by the rotation of the silicon substrate. It becomes difficult to receive. On the other hand, when the carrier gas flow rate is small, the flow velocity of the vapor phase growth gas is low, and thus the course of the vapor phase growth gas is easily affected by the rotation of the silicon substrate (rotation of the silicon substrate). Easy to be dragged in the direction). Therefore, it is possible to change the course of the raw material gas as the carrier gas flow rate is increased or decreased.

According to the present invention, by changing the course of the source gas during vapor phase growth, the position where the growth rate of the silicon thin film (eg, silicon epitaxial layer) is large on the main surface of the silicon single crystal substrate is changed. Can be made. As a result, the film thickness distribution of the silicon thin film can be made more uniform.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In this embodiment,
An example of applying a so-called single wafer type vapor phase growth apparatus as a vapor phase growth apparatus for carrying out the method for manufacturing a silicon epitaxial wafer according to the present invention will be described.

First, a single wafer type vapor phase growth apparatus 1 will be described with reference to FIG. As shown in FIG. 1, a vapor phase growth apparatus 1 includes a reaction vessel 3 in which a silicon single crystal substrate 2 (hereinafter, also simply referred to as a silicon substrate 2) is disposed during vapor phase growth, and a reaction vessel 3 3, a substantially disk-shaped susceptor 4 on which the silicon substrate 2 is placed in a substantially horizontal state, and a raw material gas (eg, trichlorosilane) and a carrier gas (eg, hydrogen gas) are placed in the reaction vessel 3. An introduction path 5 for introducing the vapor phase growth gas containing the gas and an exhaust path 6 for exhausting the gas from the reaction container 3 are provided. In addition, the vapor phase growth apparatus 1 includes a heating device (not shown) for heating the silicon substrate 2 on the susceptor 4 in the reaction container 3 to a desired temperature, and a susceptor 4 for the plate during the vapor phase growth. The silicon substrate 2 is also provided with a drive device 7 for rotating in the plate surface direction as the silicon substrate 2 is rotated in the surface direction. The drive device 7 is configured to be able to change the rotation speed of the susceptor 4 (and thus the rotation speed of the silicon substrate 2).

In the present embodiment, the vapor phase growth apparatus 1 having the above-mentioned structure is used to perform vapor phase growth as described below.

First, the silicon substrate 2 is placed on the susceptor 4 in the reaction vessel 3 with its main surface facing upward. That is, the silicon substrate 2 is arranged in a substantially horizontal state. Next, while heating the silicon substrate 2 to a desired temperature (for example, 1100 ° C.) in the supply rate-controlling region by a heating device and rotating the silicon substrate 2 in the plate surface direction, the gas for vapor phase growth is supplied to the silicon substrate 2 through the introduction path 5. The silicon epitaxial layer (hereinafter, also simply referred to as an epitaxial layer) on the main surface by supplying the silicon epitaxial layer substantially parallel to the main surface.
Vapor growth. In the present embodiment, during the vapor phase growth period, for example, at the low speed (for example, 10 rotations / minute) in the first half, and at the high speed (for example, 35 rotations / minute) in the second half,
The silicon substrate 2 is rotated (FIG. 2 (b)).
Since the entire length of the vapor phase growth period can be obtained in advance based on the film thickness of the epitaxial layer that needs to be vapor phase grown, the first half of the obtained period is set as the low speed rotation period. The period for rotating the other half at high speed may be set.

Referring to FIG. 5, the susceptor 4 is introduced into the reaction vessel 3 through the introduction path 5 in the direction of arrow A.
The flow of the vapor phase growth gas (including the source gas) supplied onto the main surface of the upper silicon substrate 2 will be described. Figure 5
As shown in, when the rotation speed of the silicon substrate 2 (and the susceptor 4) is low (for example, 10 rotations / minute), the course of the gas flow for vapor phase growth on the main surface of the silicon substrate 2 is 2 (and susceptor 4) is hardly affected by the rotation. Therefore, the gas flow for vapor phase growth has a path along the arrow C direction which is substantially the same as the arrow A direction on the main surface of the silicon substrate 2. On the other hand, when the rotation speed of the silicon substrate 2 (and the susceptor 4) is high (for example, 35 rotations / minute), the course of the gas flow for vapor phase growth on the main surface of the silicon substrate 2 is (And susceptor 4) is greatly affected by rotation. Specifically, for example, if the rotation direction of the silicon substrate 2 (and the susceptor 4) is clockwise (in the direction of arrow B in FIG. 5) in a plan view, the gas phase when the rotation speed is the above-mentioned high speed The course of the growth gas flow changes as shown by arrow D in FIG. This is because on the main surface of the silicon substrate 2, the course of the vapor phase growth gas flow is changed by being dragged by the rotating silicon substrate 2 and the susceptor 4 (specifically, for example, the upstream portion ( In the portion (E in FIG. 5), the course changes so as to move away from the arrow C, and in the downstream side (the portion F in FIG. 5), the course changes so as to approach the arrow C).

Further, for example, FIG. 3 (b) or FIG. 4 (b)
As shown in FIG. 3, when the epitaxial wafer is manufactured by setting the rotation speed of the silicon substrate 2 to be constant during the entire period of the vapor phase growth, FIG. 3A or FIG.
As shown in FIG. 5, an annular distribution is generated in the film thickness of the epitaxial layer. Specifically, when the rotation speed of the silicon substrate 2 is set to, for example, 10 rotations / minute (low speed),
The thickness of the epitaxial layer is, as shown in FIG.
It is large at the central portion and the peripheral portion, and becomes small between the central portion and the peripheral portion. On the other hand, the rotation speed of the silicon substrate 2 is, for example, 3
When the rotation speed is set to 5 revolutions / minute (high speed), the film thickness of the epitaxial layer is small in the central part, large in both side parts and small in both side parts, as shown in FIG. Will grow again in the department. Here, when the rotation speed of the silicon substrate 2 is constant during the entire period of vapor phase growth, the same is true in all cases in that the uniformity of the film thickness of the epitaxial layer is not good. It can be seen that the size of the film thickness depending on the position in the diameter direction of the epitaxial wafer varies depending on the rotation speed of the silicon substrate 2 (for example, when the rotation speed of the silicon substrate 2 is the above low speed, the film thickness is in the central portion). In the case of the above high speed, it is small in the central part, etc.).

On the other hand, as in the present embodiment, the speed is low (for example, 10 revolutions / minute) in the first half of the period of vapor phase growth.
Then, in the latter half, when the silicon substrate 2 is rotated at high speed (for example, 35 rpm), the film thicknesses of FIG. 3A and FIG. 4A are combined as shown in FIG. 2A, for example. The film thickness distribution is as described above, and the film thickness distribution of the epitaxial layer is made uniform as compared with the case of either FIG. 3A or FIG. This is because the course of the source gas (gas for vapor phase growth) can be changed in accordance with the change of the rotation speed of the silicon substrate 2, and as a result, the growth rate of the epitaxial layer is high on the main surface of the silicon substrate 2. This is because the position can be changed. Therefore, by changing the rotation speed of the silicon substrate 2 during the vapor phase growth as in the present embodiment, the growth amount of the epitaxial layer on the main surface of the silicon substrate 2 is changed over the entire period of the vapor phase growth. , And can be made to approach uniformly over the entire main surface. As a result, the film thickness distribution of the epitaxial layer in the epitaxial wafer can be made uniform.

In the above embodiment, the example in which the period for vapor phase growth is two periods, that is, the rotation speed of the silicon substrate is low and the rotation speed of the silicon substrate is high, but the rotation speeds of the silicon substrate are different from each other. The period may be three or more, and in this case, the film thickness of the epitaxial layer can be made more uniform. Further, as described above, the period for performing the vapor phase growth is not limited to the example in which the rotational speeds of the silicon substrate are different from each other, and the rotational speed of the silicon substrate is gradually changed during the period for performing the vapor phase growth. Alternatively, the film thickness of the epitaxial layer can be made more uniform. In this case, the rotation speed of the silicon substrate may be gradually changed from low speed to high speed (or from high speed to low speed), or after gradually changing from low speed to high speed, it is gradually changed to low speed again. (Or, the speed may be gradually changed from high speed to low speed and then to high speed again). In short, the mode of changing the rotation speed of the silicon substrate may be set appropriately so that the film thickness becomes more uniform in consideration of factors and the like caused by the vapor phase growth apparatus.

In the above description, the example in which the course of the raw material gas is changed by changing the rotation speed of the silicon substrate has been described, but the present invention is not limited to this, and the introduction path 5 of the raw material gas (for example, a nozzle is configured. It is also possible to change the direction of the source gas by changing the direction of (1) in a plane parallel to the plate surface direction of the silicon substrate. In this case, specifically, for example, via a drive transmission member (composed of a gear or the like) that converts the motor drive into the swing of the introduction path 5 in a plane parallel to the plate surface direction of the silicon substrate. It can be mentioned that the signal is transmitted to the introduction path 5. Alternatively, the susceptor in a plane parallel to the plate surface direction of the silicon substrate,
It may be performed by moving in a direction intersecting (for example, substantially orthogonal to) the raw material gas flow. Also in this case, for example, the motor drive may be converted and drive-transmitted by the drive transmission member.

In the above description, an example in which the present invention is applied to the case of performing vapor phase growth using a single wafer type vapor phase growth apparatus has been described, but the present invention is not limited to this. For example, like a pancake type vapor phase growth apparatus, the silicon substrates are placed in substantially horizontal states at different positions on the upper surface of the substantially disk-shaped susceptor, and the susceptor is rotated in the plate surface direction. While also rotating the silicon substrate in the plate surface direction, by supplying the raw material gas substantially parallel to the main surface of these silicon substrates, vapor phase growth is performed on these many silicon substrates at once, It may be applied to a multi-plate type vapor phase growth apparatus for manufacturing a large number of epitaxial wafers at a time. In this case, in addition to the same effects as in the above case, it is possible to reduce the difference in the amount of source gas supplied between silicon substrates that undergo vapor phase growth at once, so that epitaxial wafers that are manufactured at The layer thickness can be made uniform.

In the above description, an example in which the present invention is applied when an epitaxial wafer is manufactured by vapor phase growing an epitaxial layer on the main surface of a silicon single crystal substrate has been described, but the present invention is not limited to this. A silicon wafer is manufactured by vapor-depositing a silicon thin film (polycrystalline thin film), silicon nitride (nitride), or silicon oxide (oxide) on the main surface of a single crystal substrate by vapor phase growth. You may apply when you do.

[0020]

According to the method for producing a silicon wafer and the method for producing a silicon epitaxial wafer of the present invention, by changing the course of the raw material gas during vapor phase growth, silicon can be formed on the main surface of the silicon single crystal substrate. The position where the growth rate of the thin film (eg, silicon epitaxial layer) is large can be changed. Therefore, during the entire period of vapor phase growth, the growth amount of the silicon thin film on the main surface of the silicon single crystal substrate can be made uniform close to the entire main surface. As a result, the film thickness distribution of the silicon thin film can be made more uniform.

[Brief description of drawings]

FIG. 1 is a schematic front sectional view showing a preferred example of a vapor phase growth apparatus used in an embodiment according to the present invention.

FIG. 2A is a diagram showing an example of a film thickness distribution when the rotation speed of a silicon single crystal substrate is changed during vapor phase growth, and FIG. 2B is a view showing a mode of changing the rotation speed in this case. It is a figure.

FIG. 3A is a diagram showing an example of a film thickness distribution when the rotation speed of a silicon single crystal substrate during vapor phase growth is constant,
(B) is a diagram showing a rotation speed in this case.

FIG. 4 is a diagram showing another example of the film thickness distribution when the rotation speed of the silicon single crystal substrate during vapor phase growth is constant,
(B) is a diagram showing a rotation speed in this case.

FIG. 5 is a schematic plan view for explaining how the source gas flow changes in accordance with the rotation speed of the silicon single crystal substrate.

[Explanation of symbols]

2 Silicon single crystal substrate

Claims (5)

[Claims] 1. A main surface of a silicon single crystal substrate arranged in a substantially horizontal state is rotated substantially in parallel with the main surface of the silicon single crystal substrate while rotating in the plate surface direction. A method of manufacturing a silicon wafer in which a silicon thin film is vapor-deposited thereon, characterized in that the course of the source gas is changed during the vapor phase growth. 2. The method for manufacturing a silicon wafer according to claim 1, wherein the course of the source gas is changed by changing the rotation speed of the silicon single crystal substrate. 3. The method of manufacturing a silicon wafer according to claim 2, wherein the period for performing the vapor phase growth includes a plurality of periods in which the rotation speeds of the silicon single crystal substrate are different from each other. 4. The method of manufacturing a silicon wafer according to claim 2, wherein the rotation speed of the silicon single crystal substrate is gradually changed during the vapor phase growth. 5. A silicon single crystal substrate arranged in a substantially horizontal state is rotated in the plate surface direction, and a source gas is supplied substantially parallel to the main surface of the silicon single crystal substrate, whereby A method of manufacturing a silicon epitaxial wafer, comprising: vapor-depositing a silicon epitaxial layer on a substrate to manufacture a silicon epitaxial wafer, wherein the course of the source gas is changed during the vapor phase growth.