JP2016035080A - Susceptor cover, and vapor phase growth apparatus including susceptor cover - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a susceptor cover capable of reducing a deformation volume of the susceptor cover caused by heating, and not requiring enlargement of washing equipment; and to provide a vapor phase growth apparatus including the susceptor cover.SOLUTION: In a susceptor cover, which is installed revolvably in a chamber, and installed on a susceptor in a vapor phase growth apparatus including the susceptor having a plurality of substrate placing parts where a substrate on which a thin film is to be deposited is placed rotatably, the shape is circular, an opening part 5 is provided continuously in the circumferential direction on a portion corresponding to the substrate placing part, and a plurality of notches 6 extending from the outer peripheral edge to the inside in the radial direction are provided.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vapor phase growth apparatus that deposits a thin film on a substrate by supplying a vapor phase raw material while heating the substrate, and in particular, a susceptor cover used in the vapor phase growth apparatus and a vapor phase growth including the susceptor cover Relates to the device.

There is an ever-increasing demand for efficient semiconductor device manufacturing methods and systems from the market. Presently highly productive manufacturing systems utilize metal organic vapor phase epitaxy (MOCVD), which deposits material on several substrates.
As such a vapor phase growth apparatus, in order to uniformly form a thin film on a plurality of substrates, the susceptor is rotated and a substrate mounting member (substrate plate) for mounting the substrate is rotated as the susceptor rotates. In addition, a vapor phase growth apparatus having a mechanism for revolving a substrate during film formation is known.

In response to the demand for high productivity, the substrate diameter has been increased, the vapor phase growth apparatus has been increased in size, and the components (susceptor, susceptor cover, etc.) therein have also been increased in size.
An example of a vapor phase growth apparatus that enables such high productivity is disclosed in Patent Document 1.

10 is a sectional view of the vapor phase growth apparatus 31 disclosed in Patent Document 1, and FIG. 11 is an enlarged view of a part of FIG.
A conventional vapor phase growth apparatus 31 includes a susceptor 37 made of disc-shaped carbon and a concentric circle on the outer peripheral portion of the susceptor 37 in a flat cylindrical chamber 35 having a source gas introduction nozzle 33 disposed at the lower center. There are provided a plurality of substrate plates 39 arranged at intervals, and a ceiling plate 41 which is disposed to face the susceptor 37 and which forms a uniform ceiling in the chamber.

The chamber 35 is divided into a chamber body 35b on the susceptor side and a chamber lid 35a that is airtightly mounted on the upper peripheral wall of the chamber body 35b via an O-ring 42. A rotation driving shaft for rotating the susceptor 37 is provided at the center of the bottom of the chamber body 35 b, and the substrate plate 39 holding the substrate 43 is rotated by the rotation driving shaft so that the substrate plate 39 holding the substrate 43 is the center of the susceptor 37. And revolves by a rotation gear mechanism provided on the outer periphery of the susceptor 37.
A heater 45 for heating the substrate 43 is disposed in a ring shape below the substrate plate 39, and a ring-shaped exhaust passage is provided on the outer peripheral side of the susceptor 37.

  A susceptor cover 47 that covers a portion of the susceptor 37 other than the substrate plate is placed on the upper surface of the susceptor 37. Therefore, a space between the ceiling plate 41 and the susceptor cover 47 and the substrate 43 placed on the substrate plate 39 becomes a source gas flow path 49 for vapor phase growth, and reactive organisms accumulate.

The susceptor cover 47 is installed for the purpose of preventing the susceptor 37 from being contaminated with a reactant. By removing the dirty susceptor cover 47 from the chamber 35 and installing a new susceptor cover 47, particle contamination can be prevented and stable film formation can be performed.
As shown in FIG. 12, the susceptor cover 47 having such a function has a donut shape having a large opening 51 at the center, and the opening 53 is continuous with a portion where the substrate plate 39 is disposed. It is formed side by side in the circumferential direction.
The susceptor cover 47 has a cutting portion 55 at the narrowest portion between the adjacent opening portions 53, and the inner peripheral side 47 a and the outer peripheral side 47 b can be separated by the cutting portion 55.

JP 2012-178488 A

The lower surface of the susceptor cover 47 is in contact with the susceptor 37 heated by the heater 45, while the upper surface of the susceptor cover 47 is in contact with a relatively low temperature source gas. Therefore, deformation occurs due to a difference in thermal expansion due to a temperature difference between the upper surface and the lower surface. Further, deformation may occur due to a difference in thermal expansion of the deposit due to the deposition of the reaction product.
Among such deformations, especially the deformation that warps to the upper surface side of the susceptor cover 47, that is, the raw material gas flow path side, leads to the change of the raw material gas flow path width, and the film quality of the epitaxial wafer formed on the substrate 43 is improved. A big influence.

  FIG. 13 is a correlation diagram of the raw material gas channel width and the epitaxial film thickness (hereinafter simply referred to as “film thickness”). When the raw material gas flow path width changes, the gas flow velocity changes accordingly. In the configuration of the vapor phase growth apparatus 31, there is a correlation that the film thickness increases as the gas flow rate increases under any epitaxial growth conditions. For this reason, there is a correlation between the raw material gas flow path width and the film thickness, and as shown in FIG. 13, there is a relationship that as the raw material gas flow path width increases, the film thickness decreases. Since the change in the growth rate due to this correlation affects the film quality, it is required to keep the gas flow path width appropriate in order to produce a stable film quality product.

In Patent Document 1, in order to prevent the occurrence of cracking due to thermal stress at the closest detail where adjacent openings 53 are closest, the susceptor cover 47 is divided into two at the outer peripheral side 47b and the inner peripheral side 47a.
However, in the susceptor cover 47 which is enlarged, the above-mentioned measures can prevent cracking at the finest detail, but it is insufficient from the viewpoint of keeping the gas flow path properly, and further, the influence of deformation due to the difference in thermal expansion is not possible. Measures to make it smaller are desired.

  Further, as described above, the susceptor cover 47 needs to be removed from the chamber 35 and cleaned. As the diameter and the number of epitaxial wafers required for the vapor phase growth apparatus 31 increase, the parts to be cleaned also increase in size. Increasing the size of the cleaning device by increasing the size of the parts to be cleaned requires a large cost for capital investment for that purpose, and there is a demand for cleaning large components with the size of a conventional cleaning device.

  The present invention has been made to solve the above-described problems, and reduces the amount of deformation of the susceptor cover due to heating and does not require an increase in the size of the cleaning device, and vapor phase growth including the susceptor cover The purpose is to obtain a device.

(1) A susceptor cover according to the present invention is provided in a vapor phase growth including a susceptor having a plurality of substrate placing portions on which a substrate on which a thin film is deposited is placed so as to be able to rotate while being revolved in a chamber. A susceptor cover installed on the susceptor in the apparatus, wherein the outer shape is circular, and an opening is continuously provided in a circumferential direction at a portion corresponding to the substrate mounting portion, and the radial direction from the outer periphery A plurality of notches extending inward are provided.

(2) Further, in the above-described (1), the notch is provided so as to communicate the outer peripheral edge with the opening.

(3) Further, in the above-described (1), the notch is provided to extend from an outer peripheral edge toward a portion between the adjacent openings. .

(4) Further, in any of the above (1) to (3), the notch is notched obliquely from the front surface to the back surface of the susceptor cover, the inclination angle is θ, and the thickness of the susceptor cover Where h is the notch width and d is the notch width, 0 <d <htanθ.

(5) Further, in any of the above (1) to (4), the portion between adjacent openings is divided into an inner peripheral side and an outer peripheral side. It is.

(6) Further, in the above (5), the outer peripheral side is further divided into two or more parts.

(7) A vapor phase growth apparatus according to the present invention includes the susceptor cover according to any one of (1) to (6).

  The susceptor cover of the present invention has a circular outer shape, and an opening is continuously provided in a portion corresponding to the substrate mounting portion in the circumferential direction, and a plurality of notches extending radially inward from the outer peripheral edge are provided. As a result, the place of the thermally expanded member can be made, the susceptor cover can be prevented from being deformed out of the plane, and as a result, the change of the raw material gas flow path width can be suppressed, and a stable film quality product can be manufactured. it can.

It is explanatory drawing of the susceptor cover which concerns on one embodiment of this invention. It is explanatory drawing of the other aspect of the susceptor cover which concerns on one embodiment of this invention. It is explanatory drawing of the notch provided in the susceptor cover which concerns on one embodiment of this invention. It is explanatory drawing of the other aspect of the susceptor cover which concerns on one embodiment of this invention. FIG. 5 is an exploded view of the susceptor cover shown in FIG. 4. It is explanatory drawing of the engaging part of a susceptor cover shown in FIG. It is explanatory drawing of the other aspect of the susceptor cover which concerns on one embodiment of this invention. FIG. 8 is an exploded view of the susceptor cover shown in FIG. 7. It is a graph which shows the result of the comparative experiment performed in the Example. It is explanatory drawing of the vapor phase growth apparatus of a prior art example. It is a figure which expands and shows a part of FIG. It is explanatory drawing of the susceptor cover used for the prior art example. It is a graph which shows the relationship between raw material gas flow path width and an exponential film thickness.

The susceptor cover 1 according to the present embodiment has a large opening 3 at the center and a circular outer shape, and the overall shape is a donut shape. A plurality of openings 5 are continuously formed in the circumferential direction on the outer diameter side of the large opening 3, and a plurality of notches 6 extending radially inward from the outer periphery are provided. .
The space of the notch 6 allows the thermally expanded member to go and suppresses the susceptor cover 1 from being deformed out of the plane.

As a method of providing the notch 6, as shown in FIG. 1, the notch 6 may be provided so that the outer peripheral edge communicates with the opening 5.
In this case, the length of the notch 6 may be short and processing is easy. Further, since the notch 6 communicates with the opening 5, the in-plane deformation becomes easy when thermal stress is applied even though the notch 6 is short, and the effect of out-of-plane deformation is effective. Can be prevented.

Moreover, as shown in FIG. 2, as another aspect of providing the notch 6, the notch 6 may be provided so as to extend from the outer peripheral edge toward a portion between the adjacent openings 5. In this case, it is desirable to make the length of the notch 6 in the radial direction longer than in the case of FIG.
In the case of the notch 6 shown in FIG. 2, the rigidity of the susceptor cover 1 as a whole is ensured, and for example, there is an effect that the susceptor cover 1 is not easily deformed when being transported by a robot.

By the way, the susceptor cover 1 is originally intended to prevent the reactant product from adhering to the surface of the susceptor.
However, when the notch 6 is provided perpendicular to the susceptor, the surface of the susceptor can be seen from the surface of the susceptor cover 1, and even if gas flows along the surface of the susceptor cover 1, Reaction products can adhere to the susceptor.
In order to prevent this, it is desirable to provide the notch 6 so as to be inclined from the front surface to the back surface of the susceptor cover 1.

FIG. 3 is an explanatory diagram of a specific notch shape when the notch 6 is provided obliquely, and is a perspective view of the notch 6 and an enlarged view of the notch 6 viewed from the side surface of the susceptor cover 1. Show.
When the inclination angle of the notch 6 is θ, the thickness of the susceptor cover 1 is h, and the notch width is d, the notch width is not projected perpendicularly on the susceptor 1 by making the relationship 0 <d <htanθ. The reaction product can be prevented from adhering to the susceptor 1.

For example, when the notch 6 is inserted into the susceptor cover 1 having a thickness h = 5 mm at an inclination angle θ = 6 °, the width d of the notch 6 is made smaller than 5 mm. Note that either the inclination angle or the width of the notch 6 may be used as a reference. For example, in the above example, when the notch 6 having a width of 0.5 mm is formed in the susceptor cover 1 having a thickness of 5 mm, the oblique angle θ may be larger than 6 °.
In addition, since the thickness of the site | part which provided the notch 6 will become thin when an inclination angle becomes large, as an upper limit of (theta), about 45 degrees is good.

  As shown in FIG. 4, the notch 6 may be provided in the two-part susceptor cover 8 that has the engaging part 7 at the finest detail of the adjacent openings 5 and is divided into two in the circumferential direction. Thereby, the crack of the finest detail of the adjacent opening part 5 is prevented, and the deformation | transformation by thermal expansion can also be suppressed. FIG. 5 shows a state where the two-part susceptor cover 8 shown in FIG.

The two-part susceptor cover 8 shown in FIGS. 4 and 5 is detachably connected to the inner peripheral side 8a and the outer peripheral side 8b by the engaging portion 7.
As shown in FIG. 6, the engaging portion 7 includes an outer peripheral side engaging portion 7b and an inner peripheral side engaging portion 7a. The outer peripheral side engaging portion 7b has a step shape by having a lower protruding portion 9 whose lower half in the thickness direction protrudes in the direction of the inner peripheral side 8a. On the other hand, the inner peripheral side engaging portion 7a has an inverted shape by having an upper protruding portion 11 whose upper half in the thickness direction protrudes in the direction of the outer peripheral side 8b. And the upper protrusion part 11 of the inner peripheral side engaging part 7a can be mounted on the lower protruding part 9 of the outer peripheral side engaging part 7b. Therefore, when the outer peripheral side 8b is lifted, the inner peripheral side 8a is also At the same time it is lifted. For this reason, the entire two-part susceptor cover 8 can be lifted by supporting and lifting the outer peripheral side 8b.

  Moreover, the convex part 13 which protrudes toward the outer peripheral side 8b is formed in the front-end | tip of the upper protrusion part 11 in the inner peripheral side engaging part 7a, and the convex part 13 can be fitted in the outer peripheral side engaging part 7b. A recess 15 is formed. By fitting the convex portion 13 and the concave portion 15, the inner peripheral side 8 a and the outer peripheral side 8 b are prevented from shifting in the circumferential direction in the engaging portion 7. Accordingly, the outer peripheral side 8b and the inner peripheral side 8a are not shifted in the circumferential direction during the transfer of the two-part susceptor cover 8, and can be stably transferred. Such stable conveyance makes it easy to realize automatic conveyance.

In the two-part susceptor cover 8 provided with the engaging portion 7 shown in FIG. 6, by providing the notch 6 shown in FIGS. 4 and 5, deformation due to thermal stress is absorbed by the notch 6 and the engaging portion. Since the deformation does not reach 7, separation and integration at the engaging portion 7 can be performed smoothly.
If the notch 6 is not present and the engaging portion 7 is deformed by thermal stress, the connection between the inner peripheral side 8a and the outer peripheral side 8b cannot be made smoothly, and the automatic conveyance of the two-part susceptor cover 8 is hindered. However, this is not the case in this embodiment.

The susceptor cover requires periodic cleaning in order to remove attached reaction products. However, for example, when comparing the diameter of a susceptor cover mainly composed of a 4-inch substrate and a diameter of a susceptor cover mainly composed of an 8-inch substrate, there is a difference of about 1.5 times. A susceptor cover mainly composed of an inch substrate cannot be inserted because its size is too large, and there is a problem that it cannot be washed with an existing washing apparatus mainly composed of 4 inches.
In this respect, since the diameter of the outer peripheral side 8b of the two-part susceptor cover 8 divided into two in the circumferential direction is the same as before dividing into two as shown in FIG. 5, the above problem cannot be solved.

Therefore, as shown in FIGS. 7 and 8, the outer peripheral side of the susceptor cover is further divided into three parts to form a three-part susceptor cover 17, so that the length of the longest part can be shortened and the existing cleaning apparatus can be used. It became possible to wash. FIG. 8 shows a state in which the inner peripheral side 17a and the outer peripheral side 17b of the three-part susceptor cover 17 are disassembled.
With respect to the number of divisions on the outer periphery side of the susceptor cover, it is preferable to divide the susceptor cover as long as it can be cleaned. Therefore, in consideration of the time and effort of combination, it is better that the number of divisions is as small as possible. From a comprehensive viewpoint, 2 divisions or more and 4 divisions or less are preferable.

Since a comparative experiment for confirming the effect of the present invention was performed, this will be described below.
In the comparative experiment, the height from the reference position in the vicinity of the outermost periphery of the susceptor cover is measured in steps of a circumferential angle of 30 °, and the change in height due to heating is compared.
First, the height from the reference position in the vicinity of the outermost periphery of a conventional susceptor cover divided into two at the inner and outer circumferences was measured in steps of a circumferential angle of 30 °.
As Comparative Example 1, height displacement was measured when the conventional susceptor cover was heated at 1100 ° C.
As Example 1 of the present invention, the height displacement of the outermost peripheral portion at the time of 1100 ° C. heating of the susceptor cover 1 (see FIG. 2) in which notches 6 were added to the outer peripheral portion without dividing in the circumferential direction was measured.
Further, as Example 2 of the present invention, the displacement during heating at 1100 ° C. of the two-part susceptor cover 8 (see FIG. 4) that was divided into two in the circumferential direction and provided with the notches 6 was measured.

FIG. 9 shows the results of the experiment, where the vertical axis indicates the height displacement (au) from the reference position, and the horizontal axis indicates the susceptor cover measurement position (°).
In FIG. 9, the white circle plot shows the sample without heating, the white diamond plot shows Comparative Example 1, the black square plot shows Invention Example 1, and the black triangle plot shows Invention Example 2. .

It can be seen that the height displacement (maximum 7.3%) during heating in Example 1 of the present invention can be suppressed a little compared to the displacement during heating (maximum 8.5%) in Comparative Example 1. Further, it can be seen that the height displacement (maximum 3.5%) is greatly suppressed in the present invention example 2 in which the notch 6 is divided into two.
Further, the width of displacement in the circumferential direction is Δ2.3% in Comparative Example 1, whereas the displacement width is slightly smaller in Example 1 of the present invention, which is Δ2.0%. Furthermore, in Example 2 of the present invention, Δ1.8% is further improved and it can be seen that it is more effective.
As mentioned above, the effect which provides the notch by this invention was demonstrated.

  The present invention particularly relates to a vapor phase growth apparatus for forming a compound semiconductor, and can be used to improve the quality of a semiconductor manufactured by the apparatus.

DESCRIPTION OF SYMBOLS 1 Susceptor cover 3 Large opening part 5 Opening part 6 Notch 7 Engaging part 7a Inner peripheral side engaging part 7b Outer peripheral side engaging part 8 Two-part susceptor cover 8a Inner peripheral side 8b Outer peripheral side 9 Lower protrusion part 11 Upper protrusion Part 13 Convex part 15 Concave part 17 Three-part susceptor cover 31 Vapor phase growth apparatus 33 Raw material gas introduction nozzle 35 Chamber 35a Chamber lid 35b Chamber body 37 Susceptor 39 Substrate plate 41 Ceiling plate 42 O-ring 43 Substrate 45 Heater 47 Susceptor cover (Conventional) Example)
47a Inner circumference (conventional example)
47b Outer peripheral side (conventional example)
49 Source gas channel 51 Large opening (conventional example)
53 Opening (conventional example)
55 Cutting part

Claims (7)

A susceptor cover installed on the susceptor in a vapor phase growth apparatus including a susceptor having a plurality of substrate placement portions on which a substrate on which a thin film is deposited is placed so as to be able to rotate while being revolved in a chamber. There,
The outer shape is circular, and an opening is continuously provided in a circumferential direction at a portion corresponding to the substrate mounting portion, and a plurality of notches extending radially inward from the outer peripheral edge are provided. Susceptor cover.   The susceptor cover according to claim 1, wherein the notch is provided so that an outer peripheral edge communicates with the opening.   The susceptor cover according to claim 1, wherein the notch is provided so as to extend from an outer peripheral edge toward a portion between the adjacent openings.   The notch is notched obliquely from the front surface to the back surface of the susceptor cover, where the inclination angle is θ, the thickness of the susceptor cover is h, and the notch width is d, 0 <d <htanθ. The susceptor cover according to any one of claims 1 to 3.   The susceptor cover according to any one of claims 1 to 4, wherein the susceptor cover is divided into an inner peripheral side and an outer peripheral side at a portion between the adjacent openings.   The susceptor cover according to claim 5, wherein the outer peripheral side is further divided into two or more parts.   A vapor phase growth apparatus comprising the susceptor cover according to any one of claims 1 to 6.

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