JP6841218B2 - A susceptor and a method for manufacturing an epitaxial wafer using the susceptor - Google Patents

Description

The present invention relates to a susceptor and a method for manufacturing an epitaxial wafer using the susceptor.

Silicon wafers are widely used as semiconductor wafers. Generally, for a silicon wafer, single crystal silicon is grown by the Czochralski method (CZ method) or the like, the silicon single crystal is cut into blocks, sliced thinly, and surface grinding (wrapping) step, etching step and mirror polishing are performed. Obtained by final cleaning through a (polishing) step. After that, if various quality inspections are performed and no abnormality is confirmed, the product is shipped as a product.

Here, when crystal perfection is required more or when a multilayer structure having different resistances is required, an epitaxial layer made of a single crystal silicon thin film is vapor-deposited (epitaxial growth) on the surface of a silicon wafer. To manufacture an epitaxial wafer. Also, epitaxial growth is widely performed on compound semiconductor wafers such as SiC and GaAs other than silicon wafers. As an epitaxial growth device for performing epitaxial growth, a single-wafer-type epitaxial growth device in which an epitaxial layer is formed one by one on the surface of a semiconductor wafer and a batch-type epitaxial growth device in which an epitaxial layer is formed on the surfaces of a plurality of semiconductor wafers at the same time are known. ..

FIG. 1 shows a general single-wafer type epitaxial growth apparatus 150 used for forming an epitaxial layer on a semiconductor wafer W. In this epitaxial growth apparatus 150, the upper liner 151 and the lower liner 152 for maintaining airtightness are provided, and the epitaxial growth furnace in the apparatus is partitioned by the upper dome 153 and the lower dome 154. A susceptor 1 for horizontally placing the semiconductor wafer W is provided inside the epitaxial growth furnace.

Next, a conventionally known general susceptor 1 will be described with reference to FIG. FIG. 2 shows a plan view of the susceptor 1 and a schematic view of a cross-sectional view taken along the line AA. The susceptor 1 is provided with a circular concave counterbore portion 11, and the semiconductor wafer W is provided so that the rotation center axis of the counterbore portion 11 and the rotation center axis of the semiconductor wafer W are concentric axes at the _{center axis C 0.} It will be placed. Then, when the epitaxial growth is performed, the semiconductor wafer W is placed on the counterbore portion 11 of the susceptor 1, and the growth gas (source gas) is sprayed onto the surface of the semiconductor wafer W while rotating the susceptor 1.

The semiconductor wafer W and the susceptor 1 are in contact with each other at the ledge portion 11L. Further, in FIG. 2, the radial distance L between the central axis of the susceptor 1 and the opening edge 11C of the counterbore portion 11 is constant in the circumferential direction. _{Therefore, the distance L p} between the radial outer end surface of the semiconductor wafer W, which is also called the pocket width, and the inner peripheral wall surface 11A is also constant in the circumferential direction. Therefore, the opening edge 11C when the susceptor 1 is viewed in a plane is a circle. Generally, the outer edge of the susceptor 1 also draws a circle.

As such a susceptor, for example, in Patent Document 1, a mounting region on which a semiconductor wafer is mounted and a chamfered outer peripheral edge portion of the semiconductor wafer in a mounted state are formed on the outside of the mounting region. A susceptor having a peripheral wall portion is disclosed. The mounting region has at least a flat surface inscribed in the peripheral wall portion to support the semiconductor wafer, and the peripheral wall portion is formed so that the inner wall surface thereof is inclined outward with respect to the flat surface portion. .. With the susceptor described in Patent Document 1, it is possible to suppress a change in temperature distribution due to contact between the outer peripheral edge portion of the semiconductor wafer and the peripheral edge wall portion of the susceptor, and it is possible to obtain a uniform film thickness distribution and composition distribution. ..

Further, in Patent Document 2, a counterbore on which a semiconductor substrate is arranged is formed on the upper surface, and the counterbore includes an upper counterbore portion that supports an outer peripheral edge portion of the semiconductor substrate and the upper counterbore portion. A susceptor having a two-stage structure having a lower counterbore portion formed in the lower stage on the central side is disclosed.

Japanese Unexamined Patent Publication No. 2002-265295 Japanese Unexamined Patent Publication No. 2003-229370

Thus, various susceptors have been studied so far. However, in recent years, further improvement of the epitaxial film thickness distribution has been required, and it is expected to establish a susceptor capable of making the epitaxial film thickness distribution more uniform.

Therefore, an object of the present invention is to provide a susceptor capable of making the film thickness uniformity of the epitaxial layer more uniform, and a method for manufacturing an epitaxial wafer using the susceptor.

The present inventor has reexamined in detail the cause of variation in the film thickness distribution of the epitaxial layer when epitaxial growth is performed using a susceptor according to the prior art. Here, returning to FIG. 1, in the prior art, in general, the in-core central axis of the epitaxial growth apparatus, the susceptor rotation central axis, and the wafer rotation central axis of the semiconductor wafer W are all concentric axes at the _{central axis C 0.} It is designed to be. This is because, in order to make the film thickness distribution of the epitaxial layer uniform, the temperature distribution on the surface of the semiconductor wafer W can be made uniform at the time of epitaxial growth, and the growth gas can be uniformly sprayed onto the surface of the semiconductor wafer W. This is because it has been considered preferable to have a symmetrical structure in the epitaxial growth furnace so as to be possible.

However, when epitaxial growth is performed using the above-mentioned conventional structure susceptor 1 with reference to FIGS. 1 and 2, in reality, the undulations in which the maximum value and the minimum value are scattered in the radial epitaxial film thickness distribution. Can be seen. The waviness existing in this epitaxial film thickness distribution shows the same tendency when epitaxial growth is performed under the same growth conditions. As a cause of the formation of such waviness, when epitaxial growth is performed using the susceptor 1 of the prior art, the distribution of the growth gas flow and the temperature distribution in the apparatus show a mottled distribution during the epitaxial growth, and the symmetry of the epitaxial growth apparatus is obtained. It is considered that this is because the spot distribution is kept almost constant. Further, since the epitaxial growth rate is high on the inflow side (upstream side) of the growth gas and the epitaxial growth rate is slow on the outflow side (downstream side) of the growth gas, the semiconductor wafer is rotated along with the rotation of the susceptor to reduce the difference in growth rate. Even with homogenization, such a mottled distribution is still formed. For these reasons, it is presumed that uneven growth of epitaxial growth occurs in the surface of the semiconductor wafer, and as a result, a film thickness distribution in which maximum values and minimum values are scattered in the radial direction is formed.

Therefore, the present inventor has conceived that the semiconductor wafer is eccentrically rotated on the susceptor so as to homogenize the above-mentioned uneven distribution of the growth gas flow and the temperature distribution during epitaxial growth. By rotating the semiconductor wafer eccentrically, it is expected that growth spots can be suppressed and the film thickness uniformity of the epitaxial layer formed on the surface of the semiconductor wafer can be improved. Then, the present inventors have found that such eccentric rotation of the semiconductor wafer can be realized by using a susceptor in which the rotation center axis of the susceptor and the rotation center axis of the counterbore bottom surface of the susceptor are eccentric, and the present invention is completed. I came to do it. That is, the gist structure of the present invention is as follows.

(1) A susceptor for mounting a semiconductor wafer, the central axis of the single-wafer epitaxial growth apparatus in the furnace and the central axis of rotation of the susceptor as concentric axes.
The susceptor is provided with a concave counterbore portion on which the semiconductor wafer is placed.
A susceptor characterized in that the susceptor rotation center axis of the susceptor and the rotation center axis of the counterbore bottom surface of the counterbore portion are eccentric.

(2) The susceptor according to (1) above, wherein the eccentric distance between the susceptor rotation center axis of the susceptor and the rotation center axis of the counterbore bottom surface of the counterbore portion is 22 mm or less.

(3) The susceptor according to (1) or (2) above, wherein the eccentric distance between the susceptor rotation center axis of the susceptor and the rotation center axis of the counterbore bottom surface of the counterbore portion is 3 mm or more.

(4) The susceptor according to any one of (1) to (3) above, wherein the radial distance between the rotation center axis of the bottom surface of the counterbore and the opening edge of the counterbore is constant in the circumferential direction.

(5) The susceptor according to any one of (1) to (3) above, wherein the radial distance between the rotation center axis of the bottom surface of the counterbore and the opening edge of the counterbore changes periodically in the circumferential direction. ..

(6) The susceptor according to any one of (1) to (5) above, wherein the shoulder opening width of the susceptor is rotationally symmetric twice.

(7) The mounting step of mounting the semiconductor wafer on the susceptor according to any one of (1) to (6) above, and
An epitaxial layer forming step of forming an epitaxial layer on the surface of the semiconductor wafer,
A method for manufacturing an epitaxial wafer including
A method for manufacturing an epitaxial wafer, which comprises mounting the semiconductor wafer so that the rotation center axis of the semiconductor wafer is located on the rotation center axis of the counterbore bottom surface of the susceptor in the above-described setting step.

According to the present invention, it is possible to provide a susceptor capable of making the film thickness uniformity of the epitaxial layer more uniform, and a method for manufacturing an epitaxial wafer using the susceptor.

It is a schematic cross-sectional view of the conventionally known general epitaxial growth apparatus. It is a schematic plan view of a general susceptor known conventionally and the cross-sectional view taken along the line AA. FIG. 3 is a schematic plan view of a susceptor according to an embodiment of the present invention and a sectional view thereof BB. It is sectional drawing which shows the other aspect of the susceptor which follows one Embodiment of this invention. It is a graph which shows the radial film thickness distribution of the epitaxial layer in Experimental Example 1. It is a graph which shows the relationship between the eccentric distance and the film thickness distribution ratio in Experimental Example 2.

Hereinafter, a susceptor according to the present invention and a method for manufacturing a semiconductor epitaxial wafer using the susceptor will be described with reference to the drawings. For convenience of explanation, FIGS. 3 and 4 exaggerate the aspect ratio of each configuration and are different from the actual ratio.

It should be noted that, in the present specification, it is naturally understood that the descriptions such as "period", "symmetrical" and "constant" do not require strictness in the mathematical and geometrical senses, and it is understood that the description is not required for strictness in the mathematical and geometrical senses. The unavoidable dimensional and geometrical tolerances that accompany it are acceptable.

(Suceptor)
A susceptor 100 according to an embodiment of the present invention will be described with reference to a plan view of the susceptor 100 and a schematic view of a sectional view taken along the line BB shown in FIG. The susceptor 100 according to the embodiment of the present invention is a susceptor for mounting the semiconductor wafer W in the single-wafer epitaxial growth apparatus, and includes the in-core central axis of the single-wafer epitaxial growth apparatus and the susceptor rotation central axis C ₀ . Is a concentric axis at the central axis C _0. The susceptor 100 is provided with a concave counterbore 110 on which the semiconductor wafer W is placed, and the susceptor rotation center axis C _{0 of} the susceptor 100 and the rotation center axis 110B of the counterbore bottom surface 110B of the counterbore 110. C ₁ is eccentric.

In one embodiment shown in FIG. 3, a counterbore portion 110 having a two-stage structure (sometimes referred to as a “two-stage counterbore”) is illustrated. The counterbore portion 110 includes an upper recess that is partitioned by the outer inner peripheral wall surface 110A1 and the ledge portion 110L of the counterbore portion 110, and a lower recess that is partitioned by the inner inner peripheral wall surface 110A2 and the counterbore bottom surface 110B of the counterbore portion 110. To be equipped. The ledge portion 110L is a portion where the susceptor 100 and the semiconductor wafer W come into contact with each other. In FIG. 3, the opening diameter of the upper recess is larger than the diameter of the semiconductor wafer W, and the opening diameter of the lower recess is larger than the diameter of the semiconductor wafer W.

The portion surrounding the counterbore 110 of the susceptor 100 is the susceptor shoulder opening 120, and in FIG. 3, when the susceptor 100 is viewed in a plan view, the upper surface 120A of the susceptor shoulder opening 120 relates to a straight line connecting the _{central axes C 0} and C _1. It is provided line-symmetrically. By providing the susceptor shoulder opening 120 having such a shape, the susceptor rotation center axis C _{0 of the susceptor 100 and the rotation center axis C 1} of the counterbore bottom surface 110B of the counterbore portion 110 are eccentric. In the following, the eccentric distance between the susceptor rotation center axis C _{0 and the rotation center axis C 1} of the counterbore bottom surface 110B of the counterbore portion 110 is referred to as D.

Here, when the semiconductor wafer W is epitaxially grown using the susceptor 100, the semiconductor wafer W is placed on the susceptor 100 so that the rotation center axis of the semiconductor wafer W is located on _{the rotation center axis C 1 of the counterbore bottom surface 110B.} It will be placed. Since the susceptor rotation center axis C ₀ of the susceptor 100 is concentric with the in-core rotation center axis of the epitaxial growth apparatus, the semiconductor wafer W is deviated by the eccentric distance D and eccentrically rotates during the epitaxial growth.

Therefore, if epitaxial growth is performed using this susceptor 100, the contact time between the center of the semiconductor wafer W and the peripheral edge of the semiconductor wafer W can be made more uniform during the epitaxial growth, and the contact time with the raw material gas can be made more uniform in the radial direction. Can suppress the growth spots of. As a result, by using the susceptor 100, the film thickness uniformity of the epitaxial layer formed on the wafer surface can be improved.

Here, it is preferable that the eccentric distance D between the susceptor rotation center axis C _{0 of the susceptor 100 and the rotation center axis C 1} of the counterbore bottom surface 110B of the counterbore portion 110 is 22 mm or less. If the eccentricity distance D becomes excessive, the temperature of the counterbore portion near the outer peripheral edge of the susceptor cannot be equalized, and there is a concern that the film thickness and resistivity of the epitaxial layer formed may be significantly deviated. If it is within the range, the effect of suppressing growth spots in the radial direction due to the eccentric rotation of the semiconductor wafer W is sufficient. Further, if the eccentric distance D is more than 0 mm, the effect of the present invention can be obtained, but if the eccentric distance D is 3 mm or more, the effect of the present invention can be obtained more reliably, and it is preferable that the eccentric distance D is 5 mm or more.

In the susceptor 100 of FIG. 3, although the upper surface 120A of the susceptor shoulder opening 120 is shown as a horizontal plane, an inclined surface or a protrusion may be provided. If the shoulder width L _s of the susceptor 100 is rotationally symmetric twice, the eccentricity between the rotation center axes C ₀ and C ₁ described above can be surely realized. The width of the shoulder opening here means the width in the horizontal direction from the opening edge 110C of the upper surface 120A of the susceptor shoulder opening 120 to the outer diameter of the susceptor 100. Further, in order to realize such eccentricity, it is possible not necessarily by adjusting the _{shoulder width L s.} In the susceptor 100 shown in FIG. 3, the rotation center axis C ₁ of the counterbore bottom 110B, but the radial distance L _B in the circumferential direction between the opening edge 110C of the pocket is constant, the radial distance L _{B It is possible to realize the eccentricity between the rotation center axes C 0} and C ₁ by changing in the circumferential direction, and the ledge portion 110L may be an inclined surface and the taper angle thereof may be changed in the circumferential direction. ..

Further, the rotation center axis C ₁ of the counterbore bottom 110B, it is preferable to constant in the radial distance L _B circumferential direction between the opening edge 110C of the spot facing 110, the radial distance L _B circumferential direction It is also preferable to change it periodically. In either case, the gas flow sprayed on the surface of the semiconductor wafer W can be made uniform. Note that shown in FIG. 3, an equivalent該径direction distance L _B is constant.

Further, even if the radial distance L _B to be constant, or even in the periodically changing, in any case, the susceptor 100, the pocket width L _p is a radial distance between the silicon wafer W 0 as the range of .5Mm～4mm, it is preferable to set the radial distance L _B. When the pocket width L _p is in this range, it is possible to prevent the occurrence of sticking between the semiconductor wafer W and the outer inner peripheral wall surface 110A1 of the susceptor 100. The pocket width L _p does not depend on the diameter of the silicon wafer, and it is preferable that the pocket width L p is varied within the same range even if the diameter is 150 mm to 450 mm. For example, when the diameter of the silicon wafer is 300 mm (radius 150 mm), the radial distance L corresponding to the _{pocket width L p is 151 mm to 154 mm.}

Incidentally, the radial distance L _B, when the periodically varying consequently the pocket width L _p in the circumferential direction, it is preferable to accommodate growth rate orientation dependence of a semiconductor wafer. For example, when the main surface of the silicon wafer, which is the growth surface, is the {100} surface, the growth rate orientation dependence changes in the circumferential direction at a cycle of 90 degrees, so that the influence of the film thickness distribution due to the growth rate orientation dependence is suppressed. Therefore, the pocket width L _p may be changed periodically. In Figure 3, because it illustrates the radial distance L _B is constant, the opening edge 110C draw a circle, but if the periodically changing the radial distance L _B in the circumferential direction, of the periodic function of the period The shape corresponding to the locus will be drawn.

Further, the heights of the outer inner peripheral wall surface 110A1 and the inner inner peripheral wall surface 110A2 are not particularly limited, and can be the same as a normal two-stage counterbore type susceptor.

Another aspect of the susceptor according to this embodiment is shown in the susceptor 200 of FIG. Like the susceptor 200, each of the outer inner peripheral wall surface 210A1 and the inner inner peripheral wall surface 210A2 may be inclined surfaces, and their inclination angles are also arbitrary. The susceptor 200 is the same as the susceptor 100 except that the outer inner peripheral wall surface 210A1 and the inner inner peripheral wall surface 210A2 are inclined surfaces. The explanation is omitted.

Further, in FIGS. 3 and 4, the ledge portions 110L and 210L are shown as horizontal planes. In this case, the horizontal surface and the silicon wafer W can come into surface contact with each other to support the silicon wafer W. However, the ledge portion is not limited to the horizontal plane, and may be a tapered inclined surface. In this case, the silicon wafer W and the susceptor are in point contact, and the contact area between the susceptor and the semiconductor wafer W can be reduced. Further, in FIGS. 3 and 4, the two-stage counterbore susceptor has been used as an example, but the shape of the counterbore portion is arbitrary as long as the rotation center axis of the susceptor and the rotation center axis of the bottom surface of the counterbore are eccentric. Yes, it may be a one-stage counterbore or a multi-stage counterbore having a three-stage structure or more.

Hereinafter, preferred specific embodiments of the susceptor according to the present embodiment will be described.

As the material of the susceptor, in order to reduce the contamination from the susceptor to the epitaxial film during epitaxial growth, it is common to use a carbon substrate coated with silicon carbide (SiC). However, the entire susceptor may be formed of SiC, and if the surface of the susceptor is coated with SiC, the susceptor may be composed of other materials inside. Further, it is also a preferable embodiment that a part or all of the surface of the susceptor is covered with a silicon film. The coating of the silicon film can prevent contamination from the susceptor to the epitaxial film.

Further, in the susceptor according to the above embodiment, the lift pin through holes for raising and lowering the semiconductor wafer W by inserting the lifting lift pin when mounting the semiconductor wafer W are provided on the counterbore bottom surfaces 110B and 210B of the counterbore portion. Can be done (not shown). The lift pin through hole can be appropriately provided according to the shape of the robot arm for loading the semiconductor wafer W, _{and the lift pin through hole may be provided around the susceptor rotation center axis C 0} , or the counterbore bottom surface rotation center axis C may be provided. _A lift pin through hole may be provided around 1. Further, one or a plurality of through holes may be provided so as to penetrate from the counterbore bottom surfaces 110B and 210B to the back surface side of the susceptor. When loading the semiconductor wafer W into the counterbore portion of the susceptor, it is useful for discharging the gas between the susceptor and the silicon wafer to the back surface side of the susceptor.

Further, the susceptor according to the embodiment of the present invention can be installed in a general single-wafer epitaxial growth apparatus, and the susceptor rotation center axis C ₀ is concentric with the in-core rotation center axis of the epitaxial growth apparatus. You can install it like this. If a susceptor according to an embodiment of the present invention is used, epitaxial growth can be performed in the same manner as normal epitaxial growth except that the semiconductor wafer W is eccentrically rotated at an eccentric distance D. The clearance between the peripheral edge of the susceptor and the normally installed preheat ring or lower liner may be adjusted as appropriate.

As the semiconductor wafer W to be mounted on the susceptor according to the present embodiment, a silicon wafer is preferably used, and the epitaxial layer formed on the silicon wafer is preferably a silicon epitaxial layer. However, it is of course possible to mount a compound semiconductor wafer or the like on the susceptor according to the present embodiment, and it is also applicable to heteroepitaxial growth.

(Manufacturing method of epitaxial wafer)
Further, the method for manufacturing an epitaxial wafer according to the present embodiment includes a mounting step of mounting the semiconductor wafer W on the above-mentioned susceptors 100 and 200 and an epitaxial layer forming step of forming an epitaxial layer on the surface of the semiconductor wafer W. Including. Then, in this mounting step, the semiconductor wafer W is mounted so that the rotation center axis of the semiconductor wafer W is located on _{the rotation center axes C 1} of the counterbore bottom surfaces 110B and 210B of the susceptors 100 and 200.

Further, each step can be performed according to a conventional method, such as using an elevating lift pin in the mounting step and blowing a silicon source gas onto the surface of the silicon wafer under general vapor phase growth conditions in the epitaxial growth step.

Although the embodiments of the present invention have been described above, these are examples of typical embodiments, and the present invention is not limited to these embodiments and is within the scope of the gist of the invention. Various changes can be made with.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples.

[Experimental Example 1]
(Example 1)
The susceptor 100 shown in FIG. 3 was manufactured with an eccentric distance D of 5.0 mm. Then, the susceptor 100 was installed in the single-wafer epitaxial growth apparatus 150 shown in FIG. The susceptor rotation center axis C ₀ is concentric with the rotation center axis in the growth furnace.

Further, a silicon wafer having a diameter of 300 mm was prepared as the semiconductor wafer W. Next, the silicon wafer was placed so that _{the rotation center axis of the silicon wafer was coaxial with the rotation center axis C 1 on the} bottom surface of the counterbore of the susceptor 100. Then, a silicon epitaxial layer was epitaxially grown on the surface of the silicon wafer to obtain an epitaxial silicon wafer.

In manufacturing the silicon epitaxial wafer, the silicon wafer was introduced into the epitaxial film forming chamber and placed on the susceptor 100 using a lift pin. Subsequently, hydrogen gas was supplied at 1130 ° C., hydrogen baking was performed, and then an epitaxial silicon film of silicon was grown by 4 μm at 1130 ° C. to obtain an epitaxial silicon wafer. Here, trichlorosilane gas was used as the raw material source gas, diboran gas was used as the dopant gas, and hydrogen gas was used as the carrier gas.

(Conventional example 1)
An epitaxial silicon wafer was obtained by epitaxially growing in the same manner as in Example 1 using a susceptor having a counterbore shape similar to that of the susceptor 100 except that the eccentric distance D was 0 mm.

<Evaluation: Measurement of film thickness of epitaxial layer>
Using an FT-IR type film thickness measuring device (manufactured by Nanometrics Co., Ltd .: QS-3300 series), the film thickness distribution of the epitaxial film of the epitaxial wafer produced in Example 1 and Conventional Example 1 was measured, respectively. The results are shown in FIG. However, the epitaxial film thickness corresponding to the vertical axis of the graph in FIG. 5 is shown using a relative value in which the average film thickness is 1 (numerical value on the vertical axis: 1.0 in the graph). Further, the film thickness distribution of the epitaxial layer in the region from the outer edge of the wafer to 10 mm is omitted for simplification of the graph. Further, in FIG. 5, the negative distance from the center of the wafer means the opposite direction when the predetermined radial direction is the positive direction.

From the graph of FIG. 5, it was confirmed that in Example 1, the film thickness distribution of the epitaxial layer could be made more uniform as compared with Conventional Example 1. Further, when the film thickness distribution rate (±%) with respect to the average film thickness is defined according to the following formula [1], the film thickness distribution rate of Example 1 is 1.09%, and the film thickness distribution rate of Conventional Example 1 is 1.13%. Is.

[Experimental Example 2]
A susceptor having the same counterbore shape as the susceptor produced in Example 1 and having an eccentric distance D changed from 1.0 mm to 22.0 mm in 1.0 mm units was produced. Using these susceptors, a silicon epitaxial wafer was produced in the same manner as in Example 1. The graph of FIG. 6 shows the correspondence between the film thickness distribution ratio of the epitaxial layer obtained by the above formula [1] and the eccentric distance D. As the susceptor having an eccentric distance D of 0 mm, the susceptor used in Conventional Example 1 was used.

From FIG. 6, it was confirmed that the use of the eccentric susceptor improved the film thickness distribution ratio as compared with the case of using the eccentric susceptor of Conventional Example 1. In particular, when the eccentric distance D was 5.0 mm or more, the effect of improving the film thickness distribution ratio became steeper, and when the eccentric distance D was 18.0 mm, the improvement effect was maximized. It was also confirmed that the improvement effect was gradually relaxed when the eccentric distance D exceeded 18.0 mm, but it was confirmed that the improvement effect of the film thickness distribution was surely obtained up to the eccentric distance D of 22.0 mm. It was.

In this experiment, except for the susceptor, the experiment was carried out under the same epitaxial growth conditions. It is presumed that the optimum eccentric distance D can fluctuate when the epitaxial growth conditions are different. However, if an eccentric susceptor is used and the eccentric distance D is 22.0 mm or less, the film thickness distribution is improved. The effect is surely obtained.

According to the present invention, it is possible to provide a susceptor capable of making the film thickness uniformity of the epitaxial layer more uniform, and a method for manufacturing an epitaxial wafer using the susceptor.

100 Suceptor 110 Counterbore 110A1 Outer inner wall 110A2 Inner inner wall 110B Bottom 110C Opening edge 110L Ledge 150 Epitaxial growth device 151 Upper liner 152 Lower liner 153 Upper dome 154 Lower dome C ₀ Suceptor rotation center axis C ₁ Counterbore bottom Rotation center axis D Eccentric distance W Semiconductor wafer L Radial distance between the rotation center axis of the bottom surface of the counterbore and the opening edge of the counterbore L _p Pocket width

Claims (5)

A susceptor for mounting a semiconductor wafer, the central axis of the single-wafer epitaxial growth apparatus in the furnace and the central axis of rotation of the susceptor as concentric axes.
The susceptor is provided with a concave counterbore portion on which the semiconductor wafer is placed.
The susceptor rotation center axis of the susceptor and the rotation center axis of the counterbore bottom surface of the counterbore portion are eccentric .
The susceptor is characterized in that the eccentric distance between the susceptor rotation center axis of the susceptor and the rotation center axis of the counterbore bottom surface of the counterbore portion is 22 mm or less. A susceptor for mounting a semiconductor wafer, the central axis of the single-wafer epitaxial growth apparatus in the furnace and the central axis of rotation of the susceptor as concentric axes.
The susceptor is provided with a concave counterbore portion on which the semiconductor wafer is placed.
The susceptor rotation center axis of the susceptor and the rotation center axis of the counterbore bottom surface of the counterbore portion are eccentric .
The susceptor is characterized in that the eccentric distance between the susceptor rotation center axis of the susceptor and the rotation center axis of the counterbore bottom surface of the counterbore portion is 3 mm or more. The susceptor according to claim 1 or 2 , wherein the radial distance between the rotation center axis of the counterbore bottom surface and the opening edge of the counterbore is constant in the circumferential direction. The susceptor according to claim 1 or 2 , wherein the radial distance between the rotation center axis of the counterbore bottom surface and the opening edge of the counterbore changes periodically in the circumferential direction. A mounting step of mounting a semiconductor wafer on the susceptor according to any one of claims 1 to 4.
An epitaxial layer forming step of forming an epitaxial layer on the surface of the semiconductor wafer,
A method for manufacturing an epitaxial wafer including
A method for manufacturing an epitaxial wafer, which comprises mounting the semiconductor wafer so that the rotation center axis of the semiconductor wafer is located on the rotation center axis of the counterbore bottom surface of the susceptor in the above-described setting step.

Images