JP2003110011A - Suscepter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a suscepter which does not generate temperature difference in a wafer by increasing thickness of the low temperature area L on the suscepter S focusing on that eddy current loss is proportional to thickness of suscepter S and is inversely proportional to a specific resistance thereof. SOLUTION: The suscepter S can obtain a flat intra-surface temperature distribution by providing the region which is thicker than the internal region at the outer most circumferential region in order to make larger the eddy current loss of the external circumferential part than that of the internal region.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to Si (silicon).
Used for vapor phase growth on semiconductor single crystal substrates such as
It relates to a susceptor for a high-frequency induction heating furnace, and particularly relates to improvement of temperature distribution in the susceptor plane.

[0002]

2. Description of the Related Art Conventionally, a so-called pancake type furnace having a vertical structure as shown in FIG. 4 has been most commonly used as a typical single crystal vapor phase growth furnace. Is a work coil K for generating a high frequency magnetic field inside a bell jar B made of transparent quartz that is airtightly partitioned.
And arrange the rotatable turntable T directly above it,
Further, the susceptor S is placed directly above it. Further, a nozzle n for supplying the raw material gas into the furnace is arranged at the center of the rotary shaft of the turntable T to constitute the furnace.

In actual vapor phase growth, a wafer W of Si or the like to be grown is closely mounted on the susceptor S, and a growth raw material such as SiCl ₄ or SiHC.
L ₃ is supplied from the small hole of the nozzle n into the bell jar B using H ₂ as a carrier gas. At that time, the wafer is heated to a temperature of 1000 ° C. or higher. The principle of heating is that by applying a high frequency current to the coil K, a high frequency magnetic field H that vertically changes in the thickness direction of the susceptor S acts. As shown in FIG. 1C, an eddy current that flows around the magnetic field lines in a vortex shape is generated in the susceptor S, and the eddy current and the specific resistance p (Ω) peculiar to the material of the susceptor S are generated.
cm) causes a loss (eddy current loss), which causes the susceptor to generate heat.

However, in the conventional vapor phase growth as described above, the temperature distribution of the susceptor S tends to be low in the outer peripheral portion as shown in FIG. 1 (b), and the wafer W mounted on the susceptor S tends to be low. Among them, the outer portion of the wafer W located on the outer peripheral portion frequently suffers from crystal defects called slip due to the temperature difference, and the product corresponding to the relevant portion becomes defective, resulting in a large decrease in yield. .

[0005]

Therefore, the problem to be solved by the present invention is to overcome the above-mentioned conventional problems, improve the temperature distribution on the susceptor S, and all the wafers W mounted thereon. The purpose of the present invention is to provide a susceptor structure that does not generate a temperature difference in.

[0006]

The present invention focuses on the fact that the eddy current loss is proportional to the thickness of the susceptor S and inversely proportional to the specific resistance, and increases the wall thickness of the low temperature portion L on the susceptor S. Thus, the susceptor that does not generate a temperature difference in the wafer is provided.

That is, according to the present invention, the outermost peripheral portion is provided with a portion thicker than the inner region so that the eddy current loss in the outer peripheral portion is larger than that in the inner portion, and a flat in-plane temperature distribution can be obtained. The problem is solved by the means.

Further, according to the present invention, by stacking heat generating blocks of the same quality as the susceptor S main body on the outermost peripheral portion, the eddy current loss in the outer peripheral portion is made larger than that in the inner portion so that a flat in-plane temperature distribution can be obtained. The problem is solved by the means.

Further, according to the present invention, a high-frequency magnetic field H is applied to a region L'having a low temperature in the plane to stack a heat generating block made of a material which causes an eddy current loss, so that a flat in-plane temperature is obtained. The problem is to be solved by means of which distribution is obtained.

[0010]

DETAILED DESCRIPTION OF THE INVENTION A susceptor according to an embodiment of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 is an explanatory diagram of a susceptor according to a first embodiment of the present invention. FIG. 1 shows an example in which the first embodiment of the present invention is applied to a carbon susceptor S used when performing vapor phase growth on a Si single crystal substrate. 1A is a schematic sectional view of the carbon susceptor S, and FIG. 1B is a plan view seen from above.
(C) is a diagram of a flat temperature distribution over the entire surface of the susceptor.
Since the outermost peripheral region H is thick, the temperature drop (the wavy line in the figure) of the outer peripheral portion in the conventional susceptor structure shown in FIG. This results in a flat temperature distribution.

(Second Embodiment) FIG. 2 is an explanatory view of a susceptor according to a second embodiment of the present invention. Figure 2 (a) shows
On the susceptor S having a conventional flat plate structure, a ring-shaped heat generating block S ′ of the same quality is placed so as to have the same effect as in FIG. Similar to the above, a flat temperature distribution can be obtained over the entire surface of the susceptor.

(Third Embodiment) FIG. 3 is an explanatory diagram of a susceptor according to a third embodiment of the present invention. When observing the temperature distribution on the susceptor S surface with an infrared camera through the viewing window of the bell jar B, for example, when the temperature of a specific wafer position region is low (L ′ in the figure), the wafer position is surrounded. A heating block S ′ of the same quality (here, carbon) as the shaped susceptor is placed to compensate for the temperature, and a uniform temperature distribution is realized over the entire surface of the susceptor.

Here, the heat generating block S'for compensating the temperature may be of the same quality as the main body of the susceptor S, but it is not limited as long as it is a material such as glassy carbon which causes an eddy current loss due to the action of a high frequency magnetic field. It does not have to be homogeneous.

The shape of the heat generating block S'is not particularly limited, and in addition to a ring shape, a disk shape, a square plate shape,
A combination of sizes and small pieces that match the shape of the region to be supplemented such as a rod may be used. In short, by arranging them in the vicinity of the low temperature portions L and L'on the susceptor surface, the temperature is compensated and a uniform temperature distribution is obtained. It is the gist of the present invention to be made possible.

[0016]

As described above, according to the present invention,
Since a uniform temperature distribution can be made over the entire surface of the susceptor S, it is possible to eliminate a decrease in yield of a workpiece such as a wafer mounted thereon due to a temperature difference.

Although the present embodiment exemplifies a vertical pancake type vapor phase growth reactor, the present invention can be applied to any horizontal type and any shape and material of the susceptor body. Naturally, the contents of the present invention can be applied not only individually but also in combination.

Further, according to the present invention, it is extremely easy to apply any apparatus as long as it is an induction heating type heating furnace as well as a high frequency.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a susceptor according to a first embodiment of the present invention. 1A is a schematic sectional view of the carbon susceptor S, FIG.
1B is a plan view seen from above, and FIG. 1C is a susceptor S.
The figure of the flat temperature distribution of the whole surface.

FIG. 2 is an explanatory diagram of a susceptor according to a second embodiment of the present invention. FIG. 2A is a diagram showing a state where a ring-shaped heat generating block S ′ of the same quality is placed on a conventional flat plate structure susceptor S,
2B is a plan view seen from above, and FIG. 2C is a diagram showing a flat temperature distribution over the entire surface of the susceptor S.

FIG. 3 is an explanatory diagram of a susceptor according to a third embodiment of the present invention. FIG. 3A is a diagram of a susceptor S having a flat plate structure, and FIG.
Is a diagram of the temperature distribution of each part of the susceptor.

FIG. 4 is an explanatory diagram of a schematic configuration of a conventional vapor phase growth reactor and temperature distribution of a susceptor. FIG. 4A is a configuration diagram of the vapor phase growth reactor, and FIG. 4B is a diagram of temperature distribution of each part of the susceptor.

[Explanation of symbols]

B bell jar K work coil T turntable S susceptor W wafer n nozzle L, L'Low temperature part on the susceptor surface H Thickened part on the susceptor S'heating block

Continued front page    F-term (reference) 4K030 AA06 AA17 BA29 BB02 CA04                       FA10 GA02 JA10 KA23 LA15                 5F031 CA02 HA02 HA37 HA59 MA28                       PA30                 5F045 BB02 DP03 DP15 EK03 EM02

Claims (3)

[Claims] 1. An eddy current loss in the outer peripheral portion is made larger than that in the inner portion by providing a portion thicker than the inner region in the outermost peripheral portion so that a flat in-plane temperature distribution can be obtained. Characteristic susceptor. 2. The eddy current loss in the outer peripheral portion is made larger than that in the inner portion by stacking heat generating blocks of the same quality as the susceptor body on the outermost peripheral portion, so that a flat in-plane temperature distribution can be obtained. The susceptor according to claim 1. 3. A flat in-plane temperature distribution can be obtained by stacking a heating block made of a material that causes an eddy current loss by applying a high-frequency magnetic field in a region where the temperature is low in the plane. Claim 1 characterized by the above-mentioned.
Or the susceptor described in 2.