JPS6155766B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in a prefabricated barrel-type susceptor.

In recent years, when forming an epitaxial growth layer by flowing a deposition gas onto a wafer, a barrel-type susceptor that can fit and hold a plurality of wafers into its sidewall has been used. Barrel type susceptors are classified into integral type and assembled type. The advantage of an assembled barrel-type susceptor is that it can shorten processing time because the individual shapes are simpler than that of a one-piece type, and when coating the surface with a silicon carbide film, it is easy to apply a uniform silicon carbide coating. has. In addition, the side wall of this susceptor that fits and holds the wafer is made up of multiple plate-like pieces, and even if one of them becomes unusable due to a defect, you can replace the other plate-like pieces by simply replacing that one piece. has the advantage of being able to be used repeatedly.
For this reason, most barrel-type susceptors currently in use are of the assembled type.

Incidentally, a conventional prefabricated barrel type susceptor having a structure shown in FIGS. 1 and 2 is known. That is, in the figure, 1 and 2 are an upper support plate and a lower support plate that are vertically spaced apart and held by pillars 3a and 3b, and these support plates 1 and 2 have similar hexagonal shapes, and the lower support plate 2 has a larger shape than the upper support plate 1. In addition, the upper support plate 1
On the sides of the lower support plate 2 are six trapezoidal plate pieces 4 made of, for example, an artificial graphite base material covered with a silicon carbide film.
... 4 are fixed, and the adjacent plate pieces 4, 4 are in contact with each other with their flat surfaces. These plate-like pieces 4...4
has a circular recess 5 for inserting and holding the wafer.
5 is formed. Further, the upper support plate 1 has a shaft 6 for rotating and suspending the susceptor.
is installed. Note that a temperature sensor 7 is inserted from the lower support plate 2 to detect the temperature of the internal space surrounded by the support plates 1, 2 and the plate-like pieces 4...4. In order to form an epitaxial growth layer on a wafer using a susceptor having such a structure, the plate-like pieces 4...
After the wafers 8...8 are fitted and held in the recesses 5...5 of 4, they are rotated by the shaft 6, and silicon gas is supplied from above while heating the wafers 8...8 with, for example, a lamp to inject silicon onto the wafers 8...8. forming an epitaxial growth layer;

However, in the conventional susceptor described above, since the plurality of plate-shaped pieces 4...4 that fit and hold the wafer are in contact with each other on flat surfaces, warping or twisting of the plate-shaped pieces during manufacturing may cause the adjoining A gap is created between the abutting portions of the matching plate pieces. If a gap is created between the plate-like pieces in this way, when silicon gas is supplied as a vapor deposition gas, the gas may flow into the susceptor through the gap, or the gas that has once flowed may flow out to the outside again. As a result, the gas flow on the surface of the plate into which the wafer is inserted and held becomes unstable. Moreover, the difference in surface temperature of each plate-like piece becomes large, and especially in the case of a lamp heating method, the difference in surface temperature becomes significant. As a result, there was a drawback that the quality and thickness of the epitaxial growth layer formed on the wafer were uneven.

The present invention has been made to solve the above-mentioned drawbacks, and it is possible to prevent gaps from forming in the abutting portions of adjacent plate pieces, thereby allowing vapor deposition gas to flow uniformly to the wafer of the plate pieces. The present invention aims to provide an assembled barrel-type susceptor that can be heated uniformly.

An embodiment of the present invention will be described below with reference to FIGS. 3 and 4.

In the figure, 11 and 12 are vertically spaced supports 13a,
These support plates 11 and 12 are similar to each other, for example, in a hexagonal shape, and the lower support plate 12 is larger than the upper support plate 11. These support plates 11 and 12 are formed, for example, from an artificial graphite base material covered with a silicon carbide film. Moreover, six trapezoidal plate-shaped pieces 14 . . . 14 made of an artificial graphite base material covered with a silicon carbide film are fixed to the sides of the upper support plate 11 and the lower support plate 12, for example. The side parts 15...15 of these plate-like pieces 14...14 are shaped like stepped keys, and the adjacent plate-like pieces 1
4, 14 are engaged with each other via their hook-shaped sides 15, 15. These plate-like pieces 14...14 have a large number of circular recesses 1 for inserting and holding wafers.
6...16 are formed. Furthermore, a rotating shaft 17 is inserted and fixed at the center of the upper support plate 11 via a flange portion 18 at its tip. Note that the support plates 11, 12 and the plate-like pieces 14...1
In the internal space 19 surrounded by 4, those plate-like pieces 14
...Temperature sensor 20 for detecting the temperature of 14
is inserted from the lower support plate 12.

According to such a configuration, six plate-like pieces 1
After a plurality of wafers 21...21 are fitted and held in the circular recesses 16...16 of 4...14, they are loaded into a bell gear (not shown), and when a lamp in the bell gear is energized, the wafers 21 on the plate pieces 14...14 …2
1 is heated. In this state, when the whole is rotated by the shaft 17 and a predetermined amount of silicon gas is supplied from the vapor deposition gas introducing member above the susceptor, the silicon gas flows over each of the plate-like pieces 14...14 into which the wafers 21...21 are fitted and held. . In this process of supplying silicon gas, the adjacent plate pieces 14, 14 engage with each other via the hook-shaped side parts 15, 15, and even if the plate pieces are warped or twisted during manufacture, the plate-like pieces 14, 14 Since the pieces 14 are closely connected without any gaps between them, the plate-like pieces 14...14
The flow of gas on the surface can be stabilized, and the surface temperature of each plate-shaped piece 14...14 can also be made uniform. As a result, a homogeneous and uniformly thick epitaxial growth layer can be formed on the wafers 21 . . . 21 fitted and held by the plate-shaped pieces 14 .

Note that the prefabricated barrel-type susceptor according to the present invention is not limited to the case where the side portion of the plate-like piece is shaped like a step-like key as in the above embodiment. For example, as shown in FIG. Make it into a convex key shape, and attach the other side 1
Using plate-like pieces 14'...14' in which 5b is shaped like a convex key, the plate-like pieces 14'...14' are arranged so that the convex side part 15a and the concave side part 15b are adjacent to each other. A structure may be adopted in which the side portions 15a and 15b are engaged.

The shapes of the upper support plate and the lower support plate of the susceptor according to the present invention are not limited to the hexagonal shape as in the above embodiments, but may be any polygonal shape such as pentagonal, heptagonal, or octagonal.

The material of the support plate and the plate-like piece of the susceptor according to the present invention is not limited to that made of an artificial graphite base material covered with a silicon carbide film as in the above embodiment, but some or all of these members may be made of only silicon carbide. You can also do this.

As described in detail above, according to the present invention, adjacent plate pieces can be closely engaged without any gaps between the abutting parts, and the deposition gas can be stably applied onto the surface of the plate piece in which the wafer is inserted and held. Provided is an assembly type barrel type susceptor that has remarkable effects such as being able to flow, uniformly heating a plate-like piece, and forming a homogeneous and uniformly thick epitaxial growth layer on a wafer held on the plate-like piece. It is possible.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a conventional prefabricated barrel-type susceptor, FIG. 2 is a sectional view taken along the line - in FIG. 1, and FIG. 3 is a perspective view of a prefabricated barrel-type susceptor showing an embodiment of the present invention. Figure 4 is the same as Figure 3.
FIG. 5 is a perspective view of a prefabricated barrel-type susceptor showing another embodiment of the present invention. 11... Upper support plate, 12... Lower support plate, 14,
14'... Trapezoidal plate-shaped piece, 15... Stepped hook-shaped side part, 15a... Convex hook-shaped side part, 15b... Concave hook-shaped side part, 16... Circular depression, 17... Shaft,
21...Wafer.

Claims (1)

[Claims] 1. On the sides of the upper and lower support plates that are held apart from each other vertically and have similar polygonal shapes,
In an assembly-type barrel-type susceptor in which a plurality of plate-like pieces having at least surfaces made of silicon carbide are fixed such that the sides of adjacent plate-like pieces are in contact with each other, the sides of the plate-like pieces are shaped like keys, and A prefabricated barrel-type susceptor characterized in that plate-like pieces are fixed to the sides of an upper support plate and a lower support plate by engaging their hook-shaped side parts with each other.