JP5160023B2 - Silicon wafer and method for manufacturing silicon wafer - Google Patents

Description

  The present invention relates to a silicon wafer that is a material of a device and a method for manufacturing the silicon wafer, and more particularly, to a silicon wafer having excellent strength that is difficult to cause slip extension by heat treatment in a device manufacturing process, and a method for manufacturing the silicon wafer.

Conventionally, as a silicon wafer having no crystal defects near the surface and having an excellent gettering effect in the device manufacturing process, the range of oxygen concentration and carbon concentration is controlled, and a defect-free layer is formed on the surface and in the vicinity of the surface. There is a silicon wafer in which oxygen precipitates of 1 × 10 ⁴ pieces / cm ² or more are formed inside when heat treatment is performed at a temperature of 1000 ° C. for 1 hour to 24 hours (for example, Patent Document 1).
JP 2002-57159 A

    However, in the technique described in Patent Document 1, the occurrence of slip extension due to heat treatment in the device manufacturing process is significant, and there is a problem that the wafer strength deteriorates.

  An object of the present invention is to provide a silicon wafer having an excellent strength that is difficult to cause slip extension by heat treatment in a device manufacturing process, and a method for manufacturing the silicon wafer.

In order to solve the above-mentioned problems, the present inventor has made extensive research and can prevent the extension of slip by setting the density of oxygen precipitates (BMD) in the wafer bulk to 5 × 10 ⁹ pieces / cm ³ or more. I found. However, even if the density of BMD is 5 × 10 ⁹ pieces / cm ³ or more, if the size of BMD in the wafer bulk exceeds 150 nm, minute Slip extension starting from BMD frequently occurs near the outermost peripheral part of the wafer. As a result, it was found that precipitation becomes excessive, sufficient strength cannot be obtained, and the silicon wafer may be greatly warped.

  Oxygen precipitates in the wafer bulk can be formed by growing oxygen precipitation nuclei by performing a heat treatment such as a heat treatment for forming a defect-free layer on the wafer surface layer. The density and size of the BMD vary depending on the heat treatment conditions for forming the BMD. Specifically, the BMD density decreases when the rate of temperature rise is fast, and the BMD density increases as the rate of temperature rise is slow. Also, the longer the heat treatment time, the larger the BMD size, and the shorter the heat treatment time, the smaller the BMD size.

  Further, the oxygen precipitation nuclei introduced into the silicon wafer increase as the oxygen concentration of the silicon wafer increases. Further, since carbon in the silicon wafer promotes formation of oxygen precipitation nuclei, the density of oxygen precipitates (BMD) in the wafer bulk increases as the carbon concentration increases. However, even if only the carbon concentration of the silicon wafer is increased, if the oxygen concentration does not satisfy the predetermined concentration range, the desired BMD density cannot be obtained. If the oxygen concentration and carbon concentration of the silicon wafer are too high, the size of the oxygen precipitates in the wafer bulk exceeds 150 nm, so that the effect of preventing the slip extension cannot be sufficiently obtained as described above. Further, it is desirable that the defect-free layer has at least 5 μm or more in the wafer surface layer portion in order to obtain a silicon wafer that can easily manufacture a high-quality device.

The inventor intentionally adjusts the oxygen concentration and the carbon concentration in the silicon wafer so as to form a BMD having a density of 5 × 10 ⁹ pieces / cm ³ or more and a size of 150 nm or less, respectively. It was found that a silicon wafer in which slip extension hardly occurs can be obtained by appropriately controlling the heat treatment conditions such as heat treatment for forming a defect-free layer of at least 5 μm or more on the wafer surface layer portion.

The present invention has been completed based on the above findings, and the silicon wafer production method of the present invention has an oxygen concentration of 1.2 × 10 ^{18 to} 1.8 × 10 ¹⁸ atoms / cm ³ , a carbon concentration. Is 0.5 × 10 ^{16 to} 2 × 10 ¹⁷ atoms / cm ³ , has a defect-free layer of at least 5 μm or more in the wafer surface layer portion, and the density of oxygen precipitates in the wafer bulk is 5 × 10 ⁹ / A method for producing a silicon wafer having a size of cm ³ or more and a size of 150 nm or less,
A silicon wafer having a nitrogen concentration of 5 × 10 ^{13 to} 5 × 10 ¹⁵ atoms / cm ³ manufactured from a single crystal silicon ingot having a carbon concentration of 0.5 × 10 ^{16 to} 2 × 10 ¹⁷ atoms / cm ³ is used. When heat treatment is performed in an oxidizing atmosphere under conditions of a heat treatment temperature of 1100 ° C. to 1250 ° C. and a heat treatment time of 1 to 5 hours,
In the case where the oxygen concentration is 1.2 × 10 ^{18 to} 1.4 × 10 ¹⁸ atoms / cm ³ , the temperature increase rate in the temperature range of 700 ° C. to 1000 ° C. is set to 0.1 to 1 ° C./min during the heat treatment process,
When the oxygen concentration is 1.4 × 10 ^{18 to} 1.8 × 10 ¹⁸ atoms / cm ³ , the temperature rising rate in the temperature range of 700 ° C. to 1000 ° C. is set to 1 to 5 ° C./min during the heat treatment process.
Control is performed such that the BMD density is increased as the temperature rise rate is increased to decrease the BMD density and the temperature increase rate is decreased.
In the present invention, the non-oxidizing gas atmosphere may be an argon gas, a hydrogen gas, or a mixed gas atmosphere thereof.
A silicon wafer manufactured by any one of the above-described silicon wafer manufacturing methods, having a defect-free layer of at least 5 μm or more in the surface layer portion, and the density of oxygen precipitates in the wafer bulk is 5 × 10 ⁹ Pieces / cm ³ or more and the size thereof can be 150 nm or less.
The silicon wafer of the present invention is a silicon wafer having an oxygen concentration of 1.2 × 10 ^{18 to} 1.8 × 10 ¹⁸ atoms / cm ³ and a carbon concentration of 0.5 × 10 ¹⁶ to 2 × 10 ¹⁷ atoms / cm ^3. The wafer surface layer has a defect-free layer of at least 5 μm, the density of oxygen precipitates in the wafer bulk is 5 × 10 ⁹ pieces / cm ³ or more, and the size is 150 nm or less. To do.

  In the present invention, the oxygen concentration is a concentration defined based on ASTM F121-1979, and the carbon concentration is a concentration defined based on ASTM F123-1981.

According to the silicon wafer of the present invention, the density of oxygen precipitates (BMD) in the wafer bulk is 5 × 10 ⁹ pieces / cm ³ or more and the BMD size is 150 nm or less. Extension hardly occurs, excessive precipitation due to frequent occurrence of minute Slip extension starting from BMD is prevented, and excellent strength is obtained. Moreover, since the silicon wafer of the present invention has a defect-free layer of at least 5 μm or more on the wafer surface layer portion, a high-quality device can be easily manufactured.

In the silicon wafer, the nitrogen concentration may be 5 × 10 ^{13 to} 5 × 10 ¹⁵ atoms / cm ³ .
By using such a silicon wafer, a silicon wafer having excellent strength, a wide COP annihilation width, and a thick defect-free layer can be obtained.

In order to solve the above problems, the silicon wafer manufacturing method of the present invention has an oxygen concentration of 1.2 × 10 ^{18 to} 1.4 × 10 ¹⁸ atoms / cm ³ and a carbon concentration of 0.5 × 10 ^16. A silicon wafer manufactured from a single crystal silicon ingot of ˜2 × 10 ¹⁷ atoms / cm ³ is subjected to a heat treatment temperature of 1100 ° C. to 1250 ° C., a heat treatment time of 1 to 5 hours in a non-oxidizing atmosphere, and 700 ° C. to 1000 ° C. during the heat treatment process. Heat treatment is performed at a temperature rising rate in the temperature range of 0.1 ° C./min to 0.1 ° C./min.

According to the method for producing a silicon wafer of the present invention, the density of BMD in the wafer bulk is 5 × 10 ⁹ pieces / cm ³ or more, and the size of BMD is 150 nm or less. Thus, it is possible to obtain the silicon wafer of the present invention that can prevent excessive precipitation due to frequent occurrence of minute Slip extension and can easily manufacture a high-quality device having excellent strength.

In order to solve the above problems, the silicon wafer manufacturing method of the present invention has an oxygen concentration of 1.4 × 10 ^{18 to} 1.8 × 10 ¹⁸ atoms / cm ³ and a carbon concentration of 0.5 × 10 ^16. A silicon wafer manufactured from a single crystal silicon ingot of ˜2 × 10 ¹⁷ atoms / cm ³ is subjected to a heat treatment temperature of 1100 ° C. to 1250 ° C., a heat treatment time of 1 to 5 hours in a non-oxidizing atmosphere, and 700 ° C. to 1000 ° C. during the heat treatment process. Heat treatment is performed at a temperature rising rate in the temperature range of 1 ° C. under conditions of 1 to 5 ° C./min.

Also in the method for producing a silicon wafer of the present invention, a BMD density in the wafer bulk is 5 × 10 ⁹ pieces / cm ³ or more and a BMD size is 150 nm or less, and a high-quality device having excellent strength can be easily obtained. The silicon wafer of the present invention that can be manufactured easily can be obtained.

  In the method for manufacturing a silicon wafer, the non-oxidizing gas atmosphere may be an argon gas, a hydrogen gas, or a mixed gas atmosphere thereof.

In the method for manufacturing a silicon wafer, the nitrogen concentration of the silicon wafer before the heat treatment is 5 × 10 ^{13 to} 5 × 10 ¹⁵ atoms / cm ^3, which is 5 × 10 ^{13 to} 5 × 10 ¹⁵ atoms / cm ³ . It can be set as the manufacturing method of the silicon wafer characterized by it.
By adopting such a silicon wafer manufacturing method, it is possible to obtain a silicon wafer having a large defect-free layer and a wide COP annihilation width that is difficult to cause slip extension and has excellent strength.

The silicon wafer of the present invention is a silicon wafer manufactured by the above-described silicon wafer manufacturing method, and has a defect-free layer of at least 5 μm or more on the surface layer portion, and the density of BMD in the wafer bulk is 5 × 10 5. ⁹ pieces / cm ³ or more and the size of BMD is 150 nm or less.

  According to the present invention, it is possible to provide a high-quality silicon wafer that has an excellent strength that is unlikely to cause slip extension by heat treatment in a device manufacturing process, and that can cope with high device integration.

The silicon wafer of the present invention is a silicon wafer having an oxygen concentration of 1.2 × 10 ^{18 to} 1.8 × 10 ¹⁸ atoms / cm ³ and a carbon concentration of 0.5 × 10 ¹⁶ to 2 × 10 ¹⁷ atoms / cm ^3. The wafer surface layer has a defect-free layer of at least 5 μm, the density of oxygen precipitates in the wafer bulk is 5 × 10 ⁹ pieces / cm ³ or more, and the size is 150 nm or less. To do.

In the silicon wafer of the present invention, when the density of oxygen precipitates (BMD) in the wafer bulk is less than 5 × 10 ⁹ pieces / cm ³ , the effect of preventing the slip extension cannot be sufficiently obtained. On the other hand, if the size of the BMD exceeds 150 nm, minute Slip extension starting from the BMD occurs frequently, resulting in excessive precipitation, and sufficient strength cannot be obtained, and the silicon wafer may be greatly warped.

The silicon wafer of the present invention is a single crystal silicon having an oxygen concentration of 1.2 × 10 ^{18 to} 1.4 × 10 ¹⁸ atoms / cm ³ and a carbon concentration of 0.5 × 10 ¹⁶ to 2 × 10 ¹⁷ atoms / cm ^3. A silicon wafer manufactured from an ingot is subjected to a heat treatment temperature of 1100 ° C. to 1250 ° C. in a non-oxidizing atmosphere, a heat treatment time of 1 to 5 hours, and a temperature increase rate in the temperature range of 700 ° C. to 1000 ° C. during the heat treatment process is 0.1 to It can be manufactured by performing a heat treatment under the condition of 1 ° C./min. When the temperature elevation rate is less than 0.1 mm / min, the productivity of the heat treatment process is remarkably inferior.

The silicon wafer of the present invention has a single oxygen concentration of 1.4 × 10 ^{18 to} 1.8 × 10 ¹⁸ atoms / cm ³ and a carbon concentration of 0.5 × 10 ¹⁶ to 2 × 10 ¹⁷ atoms / cm ³ . A silicon wafer manufactured from a crystalline silicon ingot is subjected to a heat treatment temperature of 1100 ° C. to 1250 ° C. in a non-oxidizing atmosphere, a heat treatment time of 1 to 5 hours, and a temperature rising rate in a temperature range of 700 ° C. to 1000 ° C. during the heat treatment process. It can also be produced by performing a heat treatment at 5 ° C./min.

In such a manufacturing method, it is desirable that the nitrogen concentration of the silicon wafer before the heat treatment is 5 × 10 ^{13 to} 5 × 10 ¹⁵ atoms / cm ³ .
When the nitrogen concentration is less than 5 × 10 ¹³ atoms / cm ³ , the effect of widening the COP annihilation width cannot be obtained sufficiently. In addition, when the nitrogen concentration exceeds 5 × 10 ¹⁵ atoms / cm ³ , nitrogen exceeds the solid solubility in silicon, which may cause dislocation during single crystal growth by the CZ method, which is not preferable.

In the silicon wafer manufacturing method, the non-oxidizing gas atmosphere is preferably argon gas, hydrogen gas, or a mixed gas atmosphere thereof.
In the manufacturing method of the present invention, the atmosphere during the heat treatment is preferably an argon gas atmosphere in order to protect the wafer surface state. In consideration of disappearance of grown-in defects, it is desirable to perform heat treatment in an atmosphere of hydrogen gas or hydrogen-containing gas.

[Experiment 1]
In order to investigate the relationship between the density of oxygen precipitates (BMD), the size of BMD, and Slip extension, the following experiment was conducted.
That is, a plurality of silicon wafers having a diameter of 200 mm with an oxygen concentration of 1.48 × 10 ¹⁸ atoms / cm ³ and a carbon concentration of 1.2 × 10 ¹⁶ atoms / cm ³ are subjected to a temperature rising process of 700 ° C. to 1000 ° C. While changing the temperature rising rate in the range of 0.5 to 10 ° C./min and changing the heat treatment time at 1175 ° C. in the range of 1 to 5 hours, a defect-free layer (DZ layer) is formed under different heat treatment conditions. A heat treatment was performed to examine the density and size of BMD.

  The heat treatment here was performed in an Ar atmosphere at the heat treatment rate shown in FIG. In FIG. 1, symbol A is a temperature rising rate of 0.5 to 10 ° C./min, 700 ° C. to 1000 ° C., symbol B is a temperature rising rate of 2.5 ° C./min, and a temperature rising process of 1000 ° C. to heat treatment temperature. , Symbol C is a heat treatment process at a heat treatment temperature of 1175 ° C. and heat treatment time of 1 to 5 hours, symbol D is a temperature drop rate of 2.5 ° C./min, heat treatment temperature of 1000 ° C., symbol E is a temperature drop rate of 7 ° C./min, 1000 The temperature lowering process from 0C to 700C is shown.

The density of BMD is a cleaved section obtained by growing precipitates by subjecting the silicon wafer after heat treatment to an additional heat treatment at 1000 ° C./16 hr in an oxidizing atmosphere, and performing wet etching (light etching) after the wafer cleavage for 2 microns. The pits on the wafer surface were counted with an optical microscope.
The BMD size was determined by measuring the size of the BMD formed during the heat treatment on the silicon wafer after the heat treatment using a transmission electron microscope (TEM). The BMD size was an average value of 10 BMDs. Moreover, when measuring the size of BMD, diagonal length was measured for both plate-like precipitates and octahedral precipitates.

  Further, heat treatment for applying a thermal stress to the silicon wafer after the heat treatment (900 ° C. input → temperature increase rate 10 ° C./min→heat treatment temperature 1150 ° C. heat treatment time 30 minutes → temperature decrease rate 3 ° C./min→ 900 ° C. was taken out), and the Slip extension generated from the wafer boat trace was observed using X-ray topography, and was classified and evaluated into the following three categories. FIG. 2 shows the relationship between the evaluation results and the density and size of BMD.

◆: Slip extension (Slip extension length generated from wafer boat trace exceeds 5mm)
Δ: Slip suppression (Slip extension length generated from wafer boat trace was 5 mm or less)
□: Excessive precipitation (Slip extension that occurred frequently near the outermost peripheral part of the silicon wafer. By TEM observation, the minute Slip extension near the outermost peripheral part is a Slip extension generated from the BMD. confirmed.)

From FIG. 2, when the density of BMD is less than 5 × 10 ⁹ pieces / cm ³ , the Slip extension length exceeds 5 mm (♦). On the other hand, when the density of BMD was 5 × 10 ⁹ pieces / cm ³ or more, the Slip extension length was 5 mm or less (Δ).
Moreover, from FIG. 2, when the BMD size exceeded 150 nm, excessive precipitation (□) was observed. Therefore, it was confirmed that by extending the BMD density to 5 × 10 ⁹ pieces / cm ³ or more and the BMD size to 150 nm or less, it is possible to prevent the slip extension.

[Experiment 2] (Sample 1 to Sample 17)
Resistivity p−, 3 to 11 Ωcm, diameter 200 mm, a plurality of silicon wafers having various oxygen concentrations and carbon concentrations shown in Table 1 are heated to 700 ° C. to 1000 ° C. as shown in Table 1. A heat treatment for forming a defect-free layer (DZ layer) is performed in an Ar atmosphere at a heat treatment rate shown in FIG. 3 while changing in a range of 0.1 to 10 ° C./min. I checked the size. Moreover, the thickness of the DZ layer in the silicon wafer after the heat treatment was measured.
Note that the heat treatment rate shown in FIG. 3 is different from the heat treatment rate shown in FIG. 1 only in that the heat treatment temperature is 1200 ° C. and the heat treatment time is 1 hr, and therefore the description of the heat treatment rate shown in FIG. 3 is omitted.

  Further, the silicon wafer after the heat treatment was subjected to the heat treatment in the same manner as in Experimental Example 1 to observe the extension of the slip generated from the wafer boat trace, and was evaluated according to the following four categories. The evaluation results are shown in Table 1.

○: No occurrence of slip extension △: Slip suppression (Slip extension length generated from wafer boat trace was 5 mm or less)
×: Slip extension (Slip extension length generated from the wafer boat trace exceeds 5 mm)
XX: Excessive precipitation (Those in which minute slip extension occurred frequently in the vicinity of the outermost peripheral portion of the silicon wafer.)

From Table 1, when the density of BMD is 5 × 10 ⁹ pieces / cm ³ or more and the size of BMD is 150 nm or less, there is no occurrence of slip extension (O) or the length of slip extension generated from the wafer boat trace is 5 mm. The following (△) was confirmed.
Further, from Table 1, in Samples 1 and 9 that are not doped with carbon and Sample 3 in which the carbon concentration is less than 0.5 × 10 ¹⁶ atoms / cm ³ , the slip extension generated from the wafer boat trace regardless of the oxygen concentration. The length exceeds 5 mm (×). Therefore, it was confirmed that slip extension can be prevented by doping carbon.
Further, as shown in Table 1, in the sample 2 having an oxygen concentration of less than 1.2 × 10 ¹⁸ atoms / cm ³ , the Slip extension length generated from the wafer boat trace exceeds 5 mm (×).

Further, as shown in Table 1, the carbon concentration is 0.6 × 10 ^{16 to} 8.1 × 10 ¹⁶ atoms / cm ³ , the oxygen concentration is 1.23 × 10 ^{18 to} 1.28 × 10 ¹⁸ atoms / cm ³ , Samples 4, 5, 6, and 7 having a temperature increase rate of 0.1 to 1 ° C./min at 700 ° C. to 1000 ° C. have no occurrence of slip extension (◯), or the length of slip extension generated from the wafer boat trace is 5 mm or less. (△). Also, in sample 8 where the temperature rising rate from 700 ° C. to 1000 ° C. is 1.5 ° C./min, sample 7 with the same carbon concentration and the same oxygen concentration is (Δ), but from the wafer boat trace. The generated slip extension length exceeded 5 mm (x).

Moreover, as shown in Table 1, the carbon concentration is 0.6 × 10 ^{16 to} 9.8 × 10 ¹⁶ atoms / cm ³ , the oxygen concentration is 1.41 × 10 ^{18 to} 1.64 × 10 ¹⁸ atoms / cm ³ , In samples 10 to 17 having a temperature increase rate of 700 ° C. to 1000 ° C. of 0.5 to 10 ° C./min, Samples 10 and 11 having a temperature increase rate of less than 1 ° C./min are excessive precipitation (xx). Samples 16 and 17 having a temperature rate exceeding 5 ° C./min were (×).

  Moreover, the thickness of the DZ layer in the silicon wafer after the heat treatment was 7 μm or more in all samples.

[Experiment 3] (Sample 18 to Sample 21)
A defect-free layer (DZ layer) on a plurality of silicon wafers having a diameter of 200 mm, an oxygen concentration of 1.5 × 10 ¹⁸ atoms / cm ³ , and various nitrogen and carbon concentrations shown in Table 2 at the following heat treatment rates in an Ar atmosphere The density and size of BMD were examined in the same manner as in Experimental Example 1.
The heat treatment rate in Experimental Example 3 is different from the heat treatment rate in Experimental Example 2 only in that the temperature rising rate in the temperature rising process from 700 ° C. to 1000 ° C. is 1 ° C./min. The description of the rate is omitted.

  Furthermore, the silicon wafer after the heat treatment was subjected to the heat treatment in the same manner as in Experimental Example 1 to observe the slip extension generated from the wafer boat trace, and was classified and evaluated into four as in Experimental Example 2. The evaluation results are shown in Table 2.

From Table 2, in all the samples, the density of BMD was 5 × 10 ⁹ pieces / cm ³ or more and the size of BMD was 150 nm or less, and no slip extension occurred (◯).

Further, every time the surface of the silicon wafers after heat treatment of Sample 12 and Sample 18 to Sample 21 is polished by 5 μm, a surface foreign matter inspection apparatus (SP-1) uses an LPD (Light Point Defect) of 0.10 μm or more. Was measured. The result is shown in FIG.
FIG. 4 is a graph showing the relationship between the wafer depth and the number of LPDs. In FIG. 4, the wafer depth means the depth from the heat-treated silicon wafer to the surface where LPD is measured.

As shown in FIG. 4, in the sample 12 not doped with nitrogen and the sample 18 having a nitrogen concentration of less than 5 × 10 ¹³ atoms / cm ³ , the number of LPDs rapidly increased at a wafer depth of 10 to 15 μm. From this, it can be seen that the COP disappearance width, that is, the thickness of the DZ layer is 10 μm. In Samples 19 and 20, the number of LPDs increases at a wafer depth of 15 to 20 μm, and the COP disappearance width is 15 μm. In Sample 21, the number of LPDs increases at a wafer depth of 20 to 25 μm, and the COP disappearance width is 20 μm. From this, it was confirmed that by setting the nitrogen concentration to 5 × 10 ¹³ atoms / cm ³ or more, a silicon wafer having a large COP annihilation width and a thick defect-free layer can be produced.

FIG. 1 is a diagram for explaining a heat treatment rate. FIG. 2 is a graph showing the relationship between the evaluation result of Slip extension and the density and size of BMD. FIG. 3 is a diagram for explaining the heat treatment rate. FIG. 4 is a graph showing the relationship between the wafer depth and the number of LPDs.

Claims (3)

The oxygen concentration is 1.2 × 10 ^{18 to} 1.8 × 10 ¹⁸ atoms / cm ³ , the carbon concentration is 0.5 × 10 ¹⁶ to 2 × 10 ¹⁷ atoms / cm ^3, and at least 5 μm or more is formed on the wafer surface layer portion. A method for producing a silicon wafer having a defect-free layer, wherein the density of oxygen precipitates in the wafer bulk is 5 × 10 ⁹ pieces / cm ³ or more and the size is 150 nm or less,
A silicon wafer having a nitrogen concentration of 5 × 10 ^{13 to} 5 × 10 ¹⁵ atoms / cm ³ manufactured from a single crystal silicon ingot having a carbon concentration of 0.5 × 10 ^{16 to} 2 × 10 ¹⁷ atoms / cm ³ is used. When heat treatment is performed in an oxidizing atmosphere under conditions of a heat treatment temperature of 1100 ° C. to 1250 ° C. and a heat treatment time of 1 to 5 hours,
In the case where the oxygen concentration is 1.2 × 10 ^{18 to} 1.4 × 10 ¹⁸ atoms / cm ³ , the temperature increase rate in the temperature range of 700 ° C. to 1000 ° C. is set to 0.1 to 1 ° C./min during the heat treatment process,
When the oxygen concentration is 1.4 × 10 ^{18 to} 1.8 × 10 ¹⁸ atoms / cm ³ , the temperature rising rate in the temperature range of 700 ° C. to 1000 ° C. is set to 1 to 5 ° C./min during the heat treatment process.
A method for producing a silicon wafer, wherein the BMD density is controlled to be lower when the temperature rising rate is faster and the BMD density is higher as the rate of temperature rise is slower.   2. The method for manufacturing a silicon wafer according to claim 1, wherein the non-oxidizing gas atmosphere is an atmosphere of argon gas, hydrogen gas, or a mixed gas thereof. A silicon wafer manufactured by the method for manufacturing a silicon wafer according to claim 1 , wherein the surface layer portion has a defect-free layer of at least 5 μm or more, and the density of oxygen precipitates in the wafer bulk is 5 × 10 5. A silicon wafer characterized by ⁹ pieces / cm ³ or more and a size of 150 nm or less.

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