JPH10284427A - Silicon wafer supporting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a silicon wafer supporting device for diffusion process of silicon wafers. SOLUTION: A silicon wafer supporting device 1 includes a plurality of holding rods 2 having grooves 5 for supporting silicon wafers 4, and end plates 3 and 3' for fixing both ends of the plurality of holding rods. The plurality of holding rods 2 are all made of single crystal silicon or polycrystalline silicon containing the same amount of dopant as the silicon wafer 4. The end plates are all made of single crystal silicon containing the same amount of dopant as the silicon wafer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silicon wafer supporting apparatus for diffusing a silicon wafer in a heating furnace.

[0002]

In general, N-type semiconductor is P, As, any one of the Sb consists 10 ¹⁴ ~10 ¹⁶ atms / cm ³ containing silicon, while the P-type semiconductor B 10
It is well known that it is composed of silicon containing ¹⁴ to 10 ¹⁶ atms / cm ³ . A silicon wafer containing any one of P, As, Sb, and B (hereinafter, referred to as a dopant) is prepared by adding a dopant manufactured by a CZ method or an FZ method to 10 ¹⁴ to 10 ¹⁶ atms / cm.
⁽³⁾ Slice and prepare a single crystal silicon ingot containing it. Diffusion processing is performed by further heating the silicon wafer obtained by slicing in a heating furnace (not shown), and the diffusion processing of the silicon wafer is usually performed in a heating furnace while being set in the silicon wafer supporting apparatus. It is done by putting. A silicon wafer supporting device is a vertical type which is put into a heating furnace in a vertical state as shown in the perspective view of FIG. 1,
Although not shown, there is a horizontal type in which the apparatus is laid horizontally and placed in a heating furnace. Here, a vertical type silicon wafer supporting apparatus will be mainly described.

The silicon wafer supporting apparatus 1 shown in FIG. 1 comprises a holding rod 2 provided with a groove 5 and two end plates 3, 3 'for detachably fixing the holding rod 2 at both ends. As shown in the front view of FIG.
The silicon wafers 4 are inserted into the grooves 5 of the holding rods 2 and are arranged while being held at regular intervals, and the silicon wafer supporting apparatus 1 is loaded into a heating furnace (not shown) while holding a plurality of the silicon wafers 4. Diffusion processing is performed on the silicon wafer. Quartz glass is often used as a material for the holding rod 2 and the end plates 3 and 3 ', but in recent years, single crystal silicon or polycrystalline silicon has been used. The single crystal silicon or the polycrystalline silicon has high purity (dopant amount: less than 10 ¹⁴ atoms / cm ³ )
The holding rod 2 of the conventional silicon wafer supporting apparatus 1 is made of high-purity single-crystal silicon or polycrystalline silicon, and an end plate 3 for detachably fixing both ends of the holding rod 2. 3 ′ are made of high-purity single-crystal silicon. The end plates 3, 3 'need to be strong because they support the plurality of holding rods 2, and are therefore made of high-purity single-crystal silicon. This is because the end plate made of polycrystalline silicon does not have enough strength to withstand the thermal shock when the furnace is taken in and out.

[0004]

[SUMMARY OF THE INVENTION However, a silicon wafer containing a 10 ¹⁴ ~10 ¹⁶ atms / cm ³ dopant, the amount conventional dopants 10 ¹⁴ atms /
A holding rod made of high-purity single-crystal silicon or polycrystalline silicon of less than ³ cm ³ and a dopant amount of 10 ¹⁴ atm
The silicon wafer supporting apparatus 1 composed of an end plate made of high-purity single crystal silicon having a purity of less than s / cm ³ is charged into a heating furnace (not shown), and is subjected to a diffusion treatment to contain the silicon wafer. The dopant moves toward the holding rod 2 made of single crystal silicon or polycrystalline silicon having a higher purity than that of the silicon wafer, and the dopant concentration in a part of the silicon wafer in contact with the groove 5 of the holding rod 2 and the vicinity thereof is a desired value. The concentration becomes lower than the dopant concentration, and the dopant concentration of the silicon wafer becomes insufficient. for that reason,
The portion of the diffusion-treated silicon wafer that contacts the groove 5 of the holding rod 2 and the vicinity thereof have a shortage of dopant concentration. Therefore, the portion where the dopant concentration is insufficient must be deleted, resulting in a reduction in yield. was there.

[0005]

Means for Solving the Problems Accordingly, the present inventors have
As a result of conducting research to solve such problems, (a) when a plurality of holding rods provided with grooves for supporting a silicon wafer are made of silicon containing the same amount of dopant as the silicon wafer, the silicon wafer becomes Even if the diffusion process is performed, the dopant does not move due to thermal diffusion, the concentration distribution of the dopant becomes uniform as a whole, and the portion in contact with the groove 5 of the holding rod 2 of the silicon wafer subjected to the diffusion process as in the related art and the vicinity thereof are deleted. (B) Since the end plates 3 and 3 ′ for removably fixing both ends of the holding rod 2 do not come into direct contact with the silicon wafer 4, the yield does not decrease. Although it may be made of high-purity single-crystal silicon as in the prior art, a single-crystal silicon containing the same amount of dopant as the holding rod 2 and the silicon wafer 4 may be used. In the prepared it is holding the rod 2 dopant without giving a change in dopant concentration of the retaining rod 2 diffuses moved to the end plate 3 and 3 'hold the rod 2
It has been found that the concentration of the dopant is more preferable because it can be kept constant.

The present invention has been made based on such knowledge, and has a plurality of holding rods provided with grooves for supporting a silicon wafer, and ends for fixing both ends of the plurality of holding rods. In a silicon wafer supporting apparatus made of a plate, each of the plurality of holding rods is made of single crystal silicon or polycrystalline silicon containing the same amount of dopant as the silicon wafer, and each of the end plates is made of the same amount of dopant as the silicon wafer. The present invention is characterized by a silicon wafer support device made of single crystal silicon containing silicon.

The dopant contained in the single crystal silicon or polycrystal silicon constituting the plurality of holding rods and the single crystal silicon constituting the end plate is any one of P, As, Sb and B, The concentration of this dopant is 10 ¹⁴ to 10 ¹⁶ atm, the same amount as the silicon wafer.
It is preferably in the range of s / cm ³ . That is,
As for the N-type semiconductor, any one of P, As, and Sb is 10
^Since the silicon wafer containing ¹⁴ to 10 ¹⁶ atms / cm ³ is manufactured, any one of P, As, and Sb, which are the same dopant as the silicon wafer, can be used for the diffusion processing of the silicon wafer for manufacturing the N-type semiconductor. Or one kind for 10
^A holding rod made of single-crystal silicon or polycrystalline silicon containing ¹⁴ to 10 ¹⁶ atoms / cm ³ and an end plate made of single-crystal silicon are used.
^Since it is made of silicon containing ¹⁴ to 10 ¹⁶ atms / cm ³ , to diffuse a P-type silicon wafer, B, which is the same dopant as the silicon wafer, is used at 10 ¹⁴ to 10 ¹⁶ a.
Using the end plate of the tms / cm ³ containing the same dopant as the holding rod and the silicon wafer made of monocrystalline silicon or polycrystalline silicon B from 10 ¹⁴ ~10 ¹⁶ atms / cm ³ comprising a single crystal silicon.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION

Example 1 B has dimensions of 8 inches in diameter, 0.75 mm in thickness, and B
Was prepared at a concentration of 1 × 10 ¹⁵ atms / cm ³ . Further, 1 × 1 of the same amount of B as the silicon wafer is added.
The same amount of B as a silicon wafer and a holding rod made of single-crystal silicon containing 0 ¹⁵ atms / cm ^{3 is} added at 1 × 10 ¹⁵ at.
An end plate made of single-crystal silicon containing ms / cm ³ was prepared, and both ends of the holding rod were fixed by the end plate to produce a silicon wafer support device. After loading the silicon wafer into this silicon wafer support device and loading it into a heating furnace maintained at 750 ° C., the temperature was raised at a rate of 10 ° C./min to 1150 ° C.
After the temperature was raised to 1150C and maintained at 1150C for 60 minutes, the furnace was cooled to 750C at a cooling rate of 1C / min, and then was taken out of the furnace to perform a diffusion process on the silicon wafer. When the concentration of B in the portion of the diffusion-treated silicon wafer in contact with the groove of the holding rod was measured, there was no decrease in the concentration of B as a dopant.

Conventional Example 1 Impurity content is 1 × 10¹³atms / cm^ThreeLess pure
Both ends of a single-crystal silicon holding rod contain impurities.
1 × 10¹³atms / cm^ThreeThe following high-purity single crystals
Fixing with silicon end plate
The device was made. This silicon wafer support device
B prepared in Example 1 was 1 × 10^Fifteenatms / cm^ThreeIncluding
A recon wafer was charged, and the above B was prepared under the same conditions as in Example 1.
1 × 10 ^Fifteenatms / cm^ThreeDiffusion of silicon wafer containing
Processing was performed. B of the silicon wafer subjected to the diffusion process
When the concentration was measured, the silicon wafer was
The B concentration at the part that contacts the groove of the holding rod made of silicon
Degree 5 × 10¹³atms / cm^ThreeAnd the desired B concentration
Less than that, where the dopant B concentration is not uniform
Occurred during the manufacture of a P-type semiconductor.
I had to delete one part.

Example 2 A sample having a diameter of 8 inches and a thickness of 0.75 mm,
Was prepared at a concentration of 1 × 10 ¹⁵ atms / cm ³ . Further, the same amount of P as the silicon wafer is 1 × 1
A holding rod made of single-crystal silicon containing 0 ¹⁵ atms / cm ³ and the same amount of P as the silicon wafer are added at 1 × 10 ¹⁵ at.
An end plate made of single-crystal silicon containing ms / cm ³ was prepared, and the silicon wafer was charged into a silicon wafer supporting device composed of the holding rods and the end plate, and was charged into a heating furnace maintained at 750 ° C. After that, the heating rate: 1 at 10 ° C./min.
After heating to 150 ° C and holding at 1150 ° C for 60 minutes,
The furnace was cooled to 750 ° C. at a rate of temperature decrease of 1 ° C./min, and then taken out of the furnace to perform a diffusion process on the silicon wafer. When the concentration of P in the portion of the silicon wafer subjected to the diffusion treatment which was in contact with the groove of the holding rod was measured, no decrease in the P concentration was observed.

Conventional Example 2 Diameter: 8 inches prepared in Example 2, thickness: 0.75 m
A silicon wafer having a size of m and containing P at 1 × 10 ¹⁵ atms / cm ^{3 was obtained by using} a silicon wafer having an impurity content of 1 × 10 ¹³ atms.
/ Cm ³ or less, and a silicon wafer support device comprising an end plate made of high-purity single-crystal silicon having an impurity content of 1 × 10 ¹³ atoms / cm ³ or less, Under the same conditions as in Example 2,
Of silicon wafer containing 1 × 10 ¹⁵ atms / cm ² . P of the silicon wafer subjected to the diffusion process
Was measured, the P of the portion where the silicon wafer was in contact with the groove of the holding rod made of high-purity single-crystal silicon was
The concentration was 6 × 10 ¹³ atms / cm ³ , which was lower than the desired P concentration. In manufacturing an N-type semiconductor, the portion where the P concentration was insufficient had to be deleted.

Example 3 A size having a diameter of 8 inches, a thickness of 0.75 mm, and A
A silicon wafer containing 1 × 10 ¹⁵ atms / cm ³ was prepared. Further, the same amount of As
1 × 10 ¹⁵ Asms / cm ^{3 of} a holding rod made of single crystal silicon and the same amount of As as that of a silicon wafer.
^An end plate made of single crystal silicon containing ¹⁵ atms / cm ³ was prepared, and the silicon wafer was charged into a silicon wafer supporting device composed of the holding rods and the end plate, and was charged into a heating furnace maintained at 750 ° C. After that, the temperature was raised to 1150 ° C. at a rate of temperature increase of 10 ° C./min, held at 1150 ° C. for 60 minutes, cooled in a furnace at a rate of 1 ° C./minute to 750 ° C., and then taken out of the furnace. A wafer diffusion process was performed. The As concentration of the portion of the diffusion-treated silicon wafer that was in contact with the groove of the holding rod was measured, and there was no portion where the As concentration was insufficient.

Conventional Example 3 Diameter: 8 inches prepared in Example 3; thickness: 0.75 m
m, and As is 1 × 10^Fifteenatms / cm^ThreeIncluding
Silicon wafers with an impurity content of 1 × 10 ¹³atm
s / cm^ThreeRetainer made of the following high-purity single-crystal silicon
1 × 10¹³atms / cm^ThreeLess than
Composed of end plates made of high-purity single-crystal silicon
Into the wafer support device, and
As is 1 × 10^Fifteenatms / cm^ThreeIncluding silicon wafer
Was performed. This diffusion-treated silicon wafer
When the concentration of As was measured, the silicon wafer was highly pure.
Contacting the groove of the holding rod made of single crystal silicon
As concentration of 3 × 10¹³atms / cm^ThreeNext place
From the place where the As concentration is lower than the desired As concentration,
At the time of manufacture, the above-mentioned As concentration insufficient part must be deleted.
did not become.

Example 4 A sample having a diameter of 8 inches and a thickness of 0.75 mm,
A silicon wafer containing 1 × 10 ¹⁵ atms / cm ³ was prepared. Further, the same amount of Sb as the silicon wafer is
1 × 10 5 Sb of the same amount as a silicon wafer and a holding rod made of single crystal silicon containing × 10 ¹⁵ atms / cm ^3
An end plate made of single crystal silicon containing ¹⁵ atms / cm ³ was prepared, and the silicon wafer was charged into a silicon wafer supporting device composed of the holding rods and the end plate, and was charged into a heating furnace maintained at 750 ° C. After that, the temperature was raised to 1150 ° C. at a rate of 10 ° C./min, and maintained at 1150 ° C. for 60 minutes. Then, the furnace was cooled to 750 ° C. at a rate of 1 ° C./min. A wafer diffusion process was performed. The concentration of Sb in the portion of the silicon wafer subjected to the diffusion treatment that was in contact with the groove of the holding rod was measured, and there was no portion where the Sb concentration was uneven.

Conventional Example 4 Diameter: 8 inches prepared in Example 4; thickness: 0.75 m
m and a silicon wafer containing Sb at 1 × 10 ¹⁵ atms / cm ³ , each having an impurity content of 1 × 10
^The Sb was charged into a silicon wafer supporting apparatus composed of a holding rod made of high-purity single crystal silicon of ¹³ atms / cm ³ or less and an end plate, and the above Sb was added at 1 × 10 ^{15 under the} same conditions as in Example 4.
A diffusion process of a silicon wafer containing atms / cm ³ was performed. When the Sb concentration of the silicon wafer subjected to the diffusion treatment was measured, the Sb concentration of the portion where the silicon wafer was in contact with the groove of the holding rod made of high-purity single crystal silicon was 4%.
× 10 ¹³ atms / cm ³ , which was lower than the desired Sb concentration.
Insufficient concentration had to be removed.

Example 5 B has a size of 8 inches in diameter and 0.75 mm in thickness.
Was prepared at a concentration of 1 × 10 ¹⁵ atms / cm ³ . Further, 1 × 1 of the same amount of B as the silicon wafer is added.
A holding rod made of polycrystalline silicon containing 0 ¹⁵ atms / cm ³ and the same amount of B as the silicon wafer at 1 × 10 ¹⁵ at
An end plate made of single-crystal silicon containing ms / cm ³ was prepared, and both ends of the holding rod were fixed by the end plate to produce a silicon wafer support device. After loading the silicon wafer into this silicon wafer support apparatus and loading it into a heating furnace maintained at 750 ° C., the temperature was raised at a rate of 10 ° C./min to 1150 ° C.
After the temperature was raised to 1150C and maintained at 1150C for 60 minutes, the furnace was cooled to 750C at a cooling rate of 1C / min, and then was taken out of the furnace to perform a diffusion process on the silicon wafer. When the concentration of B in the portion of the diffusion-treated silicon wafer in contact with the groove of the holding rod was measured, there was no decrease in the concentration of B as a dopant.

Conventional Example 5 Impurity content is 1 × 10¹³atms / cm^ThreeLess pure
Both ends of the polycrystalline silicon holding rod contain impurities.
1 × 10¹³atms / cm^ThreeThe following high-purity single crystals
Fixing with silicon end plate
The device was made. This silicon wafer support device
B prepared in Example 5 was 1 × 10^Fifteenatms / cm^ThreeIncluding
A recon wafer was charged, and the above B was prepared under the same conditions as in Example 5.
1 × 10 ^Fifteenatms / cm^ThreeDiffusion of silicon wafer containing
Processing was performed. B of the silicon wafer subjected to the diffusion process
When the concentration was measured, the silicon wafer was found to be high-purity polycrystalline.
The B concentration at the part that contacts the groove of the holding rod made of silicon
Degree 5 × 10¹³atms / cm^ThreeAnd the desired B concentration
Less than that, where the dopant B concentration is not uniform
Occurred during the manufacture of a P-type semiconductor.
I had to delete one part.

Example 6 A sample having a diameter of 8 inches and a thickness of 0.75 mm,
Was prepared at a concentration of 1 × 10 ¹⁵ atms / cm ³ . Further, the same amount of P as the silicon wafer is 1 × 1
A holding rod made of polycrystalline silicon containing 0 ¹⁵ atms / cm ³ and an end plate made of single-crystal silicon containing 1 × 10 ¹⁵ atms / cm ^{3 of} P are prepared, and a silicon wafer supporting device composed of the holding rod and the end plate After charging the silicon wafer into a heating furnace maintained at 750 ° C.,
Heating rate: The temperature was raised to 1150 ° C at a rate of 10 ° C / min,
After holding at 60 ° C. for 60 minutes, the cooling rate was 750 at 1 ° C./min.
The furnace was cooled down to ℃, and then the furnace was taken out of the furnace to perform a diffusion process on the silicon wafer. When the concentration of P in the portion of the silicon wafer subjected to the diffusion treatment which was in contact with the groove of the holding rod was measured, no decrease in the P concentration was observed.

Conventional Example 6 Diameter: 8 inches, thickness: 0.75 m prepared in Example 6
m, and P is 1 × 10^Fifteenatms / cm^ThreeIncluding
Silicon wafers with an impurity content of 1 × 10¹³atms
/ Cm^ThreeA holding lock made of the following high-purity polycrystalline silicon
1 × 10¹³atms / cm^Threebelow
Silicon wafer with end plate made of single crystal silicon
It was charged into a supporting device, and the above P was 1 × under the same conditions as in Example 6.
10^Fifteenatms / cm^ThreeDiffusion processing of silicon wafer containing
Was done. P concentration of the silicon wafer subjected to this diffusion processing
Measured, the silicon wafer was
The concentration of P at the part that contacts the groove of the holding rod
6 × 10¹³atms / cm ^ThreeFrom the desired P concentration
Is insufficient, and the P concentration is insufficient when manufacturing an N-type semiconductor.
Had to be removed.

Example 7 A size having a diameter of 8 inches, a thickness of 0.75 mm, and A
A silicon wafer containing 1 × 10 ¹⁵ atms / cm ³ was prepared. On the other hand, the same amount of As
10 ¹⁵ atms / cm ³ comprising a holding rod and As of polycrystalline silicon endplates prepared consisting of 1 × 10 ¹⁵ atms / cm ³ comprising a single crystal silicon, silicon wafer supporting device configured with the holding rod and the end plate After the silicon wafer was charged into a heating furnace maintained at 750 ° C., the temperature was increased to 1150 ° C. at a rate of 10 ° C./min.
After maintaining at 50 ° C. for 60 minutes, the temperature was lowered at a rate of 1 ° C./min for 7 minutes.
The furnace was cooled to 50 ° C. and then taken out of the furnace to perform a diffusion process on the silicon wafer. The As concentration of the portion of the diffusion-treated silicon wafer that was in contact with the groove of the holding rod was measured, and there was no portion where the As concentration was insufficient.

Conventional Example 7 Diameter: 8 inches, thickness: 0.75 m prepared in Example 7
A silicon wafer having a dimension of m and containing As at 1 × 10 ¹⁵ atms / cm ³ has an impurity content of 1 × 10
^A holding rod made of high-purity polycrystalline silicon of ¹³ atms / cm ³ or less and an impurity content of 1 × 10 ¹³ atms / c
The silicon wafer containing the end plate made of single crystal silicon containing m ³ or less was charged into the silicon wafer supporting apparatus, and a diffusion process of the silicon wafer containing 1 × 10 ¹⁵ atms / cm ^{3 of} As was performed under the same conditions as in Example 7. . When the As concentration of the silicon wafer subjected to the diffusion treatment was measured, the As concentration at a portion where the silicon wafer was in contact with the groove of the holding rod made of high-purity polycrystalline silicon was 3 × 10 ¹³ atms / cm ³ , and the desired As concentration was obtained. Since the concentration is lower than the concentration, when manufacturing the N-type semiconductor, the portion having the insufficient As concentration has to be deleted.

Example 8 A sample having a diameter of 8 inches and a thickness of 0.75 mm,
A silicon wafer containing 1 × 10 ¹⁵ atms / cm ³ was prepared. On the other hand, the same amount of Sb as the silicon wafer is 1 ×
10 ¹⁵ atms / cm ³ comprising a holding rod and Sb of polycrystalline silicon endplates prepared consisting of 1 × 10 ¹⁵ atms / cm ³ comprising a single crystal silicon, silicon wafer supporting device configured with the holding rod and the end plate After the silicon wafer was charged into a heating furnace maintained at 750 ° C., the temperature was increased to 1150 ° C. at a rate of 10 ° C./min.
After maintaining at 50 ° C. for 60 minutes, the temperature was lowered at a rate of 1 ° C./min for 7 minutes.
The furnace was cooled to 50 ° C. and then taken out of the furnace to perform a diffusion process on the silicon wafer. The concentration of Sb in the portion of the silicon wafer subjected to the diffusion treatment that was in contact with the groove of the holding rod was measured, and there was no portion where the Sb concentration was uneven.

Conventional Example 8 Diameter: 8 inches prepared in Example 8, thickness: 0.75 m
m and a silicon wafer containing Sb at 1 × 10 ¹⁵ atms / cm ³ , each having an impurity content of 1 × 10
¹³ atms / cm ³ or less of charged into the silicon wafer supporting device constructed in the end plate of the holding rod and the single crystal silicon comprising a high-purity polycrystalline silicon, Example 8 1 × the Sb under the same conditions as 10 ¹⁵ A diffusion process of a silicon wafer containing atms / cm ³ was performed. When the concentration of Sb in the silicon wafer subjected to the diffusion treatment was measured, the Sb concentration of the portion where the silicon wafer was in contact with the groove of the holding rod made of high-purity polycrystalline silicon was 4 × 10 ¹³ atms / cm ³ , and the desired Sb concentration was obtained. Since the concentration was lower than the concentration, the portion where the Sb concentration was insufficient had to be deleted when manufacturing an N-type semiconductor.

[0024]

As shown in Examples 1 to 8, the same amount of dopant as that of a silicon wafer is used at 1 × 10 ¹⁵ atoms / s.
Using a silicon wafer supporting device constructed in the end plate of cm ³ the same amount of dopant the holding rod and the silicon wafer made of monocrystalline silicon or polycrystalline silicon containing from 1 × 10 ¹⁵ atms / cm ³ comprising a single crystal silicon When the silicon wafer is subjected to the diffusion treatment, the portion where the concentration of the dopant in the silicon wafer is insufficient does not occur, and the conventional examples 1 to 8 do not occur.
It is not necessary to partially remove the silicon wafer as described above, which can contribute to an improvement in yield.

[Brief description of the drawings]

FIG. 1 is a perspective view of a silicon wafer support device.

FIG. 2 is a partial plan view showing a state where a silicon wafer is loaded into a silicon wafer support device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Silicon wafer support device 2 Holding rod 3 End plate 3 'End plate 4 Silicon wafer 5 Groove

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Fumitaka Koyamauchi 12-6 Technopark, Mita City, Hyogo Prefecture Mitsubishi Materials Corporation Mita Plant (72) Inventor Takashi Yonehisa 12-6 Technopark, Mita City, Hyogo Mitsubishi Material Co., Ltd. Mita Plant

Claims (6)

[Claims] 1. A silicon wafer supporting apparatus comprising: a plurality of holding rods provided with grooves for supporting a silicon wafer; and an end plate for removably fixing both ends of the plurality of holding rods. A silicon wafer supporting apparatus, wherein both the holding rod and the end plate are made of silicon containing the same amount of dopant as the silicon wafer. 2. The silicon wafer supporting apparatus according to claim 1, wherein each of the plurality of holding rods is made of single crystal silicon containing the same amount of dopant as the silicon wafer. 3. The silicon wafer supporting apparatus according to claim 1, wherein each of the plurality of holding rods is made of polycrystalline silicon containing the same amount of dopant as the silicon wafer. 4. The silicon wafer supporting apparatus according to claim 1, wherein each of said end plates is made of single crystal silicon containing the same amount of dopant as the silicon wafer. 5. A silicon wafer supporting apparatus comprising: a plurality of holding rods provided with grooves for supporting a silicon wafer; and an end plate for removably fixing both ends of the plurality of holding rods. The silicon is characterized in that each of the holding rods is made of single crystal silicon or polycrystalline silicon containing the same amount of dopant as the silicon wafer, and each of the end plates is made of single crystal silicon containing the same amount of dopant as the silicon wafer. Wafer support device. 6. The dopant contained in the silicon constituting the plurality of holding rods and the end plate is any one of P, As, Sb and B, and the concentration of the dopant is 10 ¹⁴ to 10. 6. The silicon wafer supporting apparatus according to claim 1, wherein the silicon wafer supporting apparatus is in a range of ¹⁶ atms / cm ³ .