JP3853453B2 - Vertical susceptor for vapor phase growth - Google Patents

Description

【０００９】
表１から、ウエーハ収容凹部以外のサセプター本体の片面の表面粗さをＲｍａｘ０．５μｍ以下とすることにより、条件出し時と実際の気相成長時との温度差を５℃以下とし得、さらにＲmax ０．１μｍ以下とすることにより、温度差を一層縮小することができ、係数を加えることなく、条件出し時と同一のパワーで実際の気相成長を行い得ることがわかる。
【００１０】
【発明の効果】
以上説明したように、本発明の気相成長用縦型サセプターによれば、ウエーハ収容凹部以外のサセプター本体の片面と半導体ウエーハの被処理面の表面粗さがＲmax ０．５μｍ以下とほぼ同様になり、両者からの放射熱がほぼ同様となるので、条件出し時と実際の気相成長時の温度差を大幅に縮小することができ、ひいては条件出し時と同一のパワーで実際の気相成長を行うことができる。
【図面の簡単な説明】
【図１】本発明に係る気相成長用縦型サセプターの実施の形態の一例を示す平面図である。
【図２】従来の気相成長用縦型サセプターの平面図である。
【符号の説明】
１ ガス導入口
２ サセプター本体
３ ウエーハ収容凹部
Ｗ 半導体ウエーハ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vertical susceptor used when vapor phase growth such as CVD or epitaxial growth is performed on a semiconductor wafer such as a silicon wafer.
[0002]
[Prior art]
Conventionally, this type of vertical susceptor for vapor phase growth has a surface coated with a CVD-SiC film using graphite as a base material to heat a semiconductor wafer by high-frequency heating, and a gas is introduced into the center as shown in FIG. A disk-shaped susceptor body 32 provided with a mouth 31 is provided with a plurality of circular wafer housing recesses 33 each having a depth of several millimeters for housing the semiconductor wafer W. The surface roughness of one surface of the susceptor body 32 is as follows. The Rmax including the wafer accommodating recess 33 is about 5 to 10 μm.
[0003]
[Problems to be solved by the invention]
However, in the conventional vertical susceptor for vapor phase growth, when producing an epitaxial wafer using this, in order to determine the epitaxial growth conditions, several semiconductor wafers are set on the susceptor, and the conditions are determined while rotating the susceptor. After that, it is common to perform full epitaxial charge of the semiconductor wafer and then perform routine epitaxial growth.However, if the routine epitaxial growth is performed with the same power condition, the condition is determined under a set of several semiconductor wafers. There is a problem that the temperature is low and a temperature difference of 10 to 20 ° C. is generated as compared with routine epitaxial growth.
This temperature difference is caused by the fact that the surface temperature of the susceptor on the same circumference on which the semiconductor wafer is set is measured when determining the conditions, even though the surface radiant heat differs between the susceptor and the semiconductor wafer. This is because the temperature of the susceptor surface is being measured.
As a result, defects in film thickness and resistance occur, and the power is set at the time of routine epitaxial growth by adding a certain coefficient to the value obtained by setting the conditions.
Accordingly, an object of the present invention is to provide a vertical susceptor for vapor phase growth that can reduce the temperature difference between the condition setting and the actual vapor phase growth.
[0004]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the vertical susceptor for vapor phase growth according to the present invention has a disk-shaped susceptor main body made of a graphite substrate and is provided with a plurality of circular wafer-accommodating recesses for accommodating a semiconductor wafer. In the vertical susceptor for phase growth, the surface roughness of one side of the susceptor main body other than the wafer-receiving recess is Rmax 0.5 μm or less.
[0005]
Here, in order to make the surface roughness of one surface of the susceptor main body other than the wafer housing concave portion into a mirror surface having an Rmax of 0.5 μm or less, diamond polishing or the like is used.
The preferred surface roughness is Rmax 0.1 μm or less.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a plan view showing an example of an embodiment of a vertical susceptor for vapor phase growth according to the present invention.
Since this vertical susceptor for vapor phase growth heats a semiconductor wafer by heating by high frequency heating, a semiconductor wafer is formed on one surface of a disc-shaped susceptor body 2 having graphite as a base material and having a gas inlet 1 in the center. A number of circular wafer accommodating recesses 3 having a depth of about 1 mm for accommodating W are provided, the surface of the susceptor is coated with a CVD-SiC film at a thickness of 50 to 300 μm, and the surface roughness of the wafer accommodating recesses 3 is provided. Rmax is 5 to 10 μm, and the other surface roughness of the susceptor body 2 is a mirror surface with Rmax 0.5 μm or less.
The above vertical susceptor for vapor phase growth has a through-hole serving as a gas inlet at the center of a disk made of a graphite substrate, and a large number of circular recesses serving as wafer-containing recesses are formed on one side thereof by counterboring. In addition, it is manufactured by applying a mirror finish to one side of the disk by diamond polishing.
When the vapor phase growth is performed on the semiconductor wafer W using the vertical susceptor for vapor phase growth having the above configuration, the surface roughness of one surface of the susceptor body 2 other than the wafer housing recess 3 and the surface to be processed of the semiconductor wafer W is Rmax 0. Since the radiant heat from both is substantially the same, the temperature difference between the condition setting and the actual vapor phase growth can be greatly reduced.
[0007]
Here, the temperature at the time of setting conditions and the actual vapor phase growth of specific examples 1 to 4 of the vertical susceptor according to the present invention in which the surface roughness of one side of the susceptor body other than the wafer housing recess was changed, It came to show in Table 1 which writes together that of the vertical susceptor of Comparative Examples 1-2 and a prior art example.
The dimensions of the susceptor (for a 5-inch wafer) are as follows.
Diameter: 600-700mm
Thickness: 8-14mm
Wafer accommodation recess diameter: 127 mm
Wafer accommodating recesses: 20 [0008]
[Table 1]

[0009]
From Table 1, by setting the surface roughness of one side of the susceptor body other than the wafer receiving recesses to Rmax 0.5 μm or less, the temperature difference between the condition setting and the actual vapor phase growth can be 5 ° C. or less, and further Rmax It can be seen that by setting the thickness to 0.1 μm or less, the temperature difference can be further reduced, and actual vapor phase growth can be performed with the same power as the condition setting without adding a coefficient.
[0010]
【The invention's effect】
As described above, according to the vertical susceptor for vapor phase growth of the present invention, the surface roughness of one surface of the susceptor main body other than the wafer housing recess and the surface to be processed of the semiconductor wafer is almost the same as Rmax 0.5 μm or less. Therefore, the radiant heat from the two is almost the same, so the temperature difference between the condition setting and the actual vapor phase growth can be greatly reduced. It can be performed.
[Brief description of the drawings]
FIG. 1 is a plan view showing an example of an embodiment of a vertical susceptor for vapor phase growth according to the present invention.
FIG. 2 is a plan view of a conventional vertical susceptor for vapor phase growth.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Gas inlet 2 Susceptor main body 3 Wafer accommodation recessed part W Semiconductor wafer

Claims (1)

In a vertical susceptor for vapor phase growth in which a large number of circular wafer accommodating recesses for accommodating a semiconductor wafer are provided on one side of a disc-shaped susceptor body made of a graphite substrate, A vertical susceptor for vapor phase growth having a surface roughness of Rmax 0.5 μm or less.

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