JPH06295912A - Manufacture of silicon wafer and silicon wafer - Google Patents

Abstract

PURPOSE:To make defectless the active layer of a device and to make low the density of oxygen deposits of the bulk part of a wafer by a method wherein a silicon wafer having a specified interstitial oxygen concentration is subjected to heat treatment in a hydrogen gas atomsphere under specified heat-treating conditions and is formed into the wafer having the distribution of the specified density of oxygen deposits. CONSTITUTION:A silicon wafer having an interstitial oxygen concentration Oi of 1.5 to 1.8X10<18>atoms/cm<3> is subjected to heat treatment in a hydrogen gas atmosphere under conditions that a heat-treating temperature is 1100 to 1300 deg.C, a heat-treating time is one minute to 48 hours and a heating-up speed within a temperature range of 1000 to 1300 deg.C in a heat-treating process is 15 to 100 deg.C/min. By this method, a wafer, which has a defect less layer containing 10<3>piece/cm<3> or less of BMDs of a size of 20nm or larger extending over at least a depth of 10mum or deeper from the surface of the wafer and has the density BMD of oxygen deposits, which is set under the conditions of BMD>=1X10<3>piece/cm<3> and BMD<=exp{9.210X10<-18>XOi+3.244}piece/cm<3>, of the internal bulk part of the wafer, can be manufactured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silicon wafer for semiconductor devices such as VLSI and a method for manufacturing the same.

[0002]

2. Description of the Related Art In a manufacturing process of a semiconductor device for VLSI, a trace amount of metal impurities mixed in a wafer and a device active region of the wafer (a depth of 10 from a wafer surface).
Micro defects existing in the range of about μm may cause deterioration in the characteristics and reliability of the manufactured semiconductor device. Therefore, various measures have been conventionally taken to reduce these metal impurities and minute defects as much as possible.

As a method of reducing metal impurities, there is a backside damage method (BSD method) in which a minute strain is provided on the back surface of a wafer by sandblasting or the like for capturing (gettering) metal impurities. A method of depositing polycrystalline silicon on the back surface of the wafer is also used.

As a measure against the latter, an epitaxial wafer having a vapor-grown single crystal silicon layer having no microdefects in the device active region is used.

Further, an intrinsic gettering method (IG method) has been developed in order to simultaneously take measures against both. The IG method heat-treats a wafer at a high temperature to diffuse outward oxygen on the wafer surface to reduce interstitial oxygen, which is a nucleus of microdefects, and to form a depleted zone (DZ layer) having no microdefects in a device active region. Let it form.
Further, in the deep region (bulk portion) below the DZ layer, the excess interstitial oxygen contained is precipitated by the high temperature heat treatment, and BMD typified by minute SiO ₂ precipitates is generated. These BMDs exert strain on the silicon matrix in the bulk portion to induce secondary dislocations and stacking faults, and getter metal impurities.

In the IG method, a plurality of stages of heat treatment are carried out for the purpose of not being affected by the thermal history of the pulled single crystal silicon ingot and utilizing a wafer having a wider oxygen concentration range. . First, in the pre-heat treatment, heat treatment is performed at a high temperature (up to 1200 ° C.) in an oxygen-containing inert gas atmosphere to diffuse oxygen outward from the wafer surface to remove BMD nuclei originally present from oxygen. Reduce and eliminate. Next, heat treatment at a low temperature (500 to 900 ° C.) in the middle stage in an oxygen atmosphere is performed to generate BMD nuclei in the bulk part. Finally, the BMD nuclei are grown and BMDs are generated and grown by heat treatment in an oxygen atmosphere at a medium temperature (up to 1000 ° C.). Various ideas have been made for the heat treatment in the middle stage, and for example, isothermal annealing, multi-stage annealing from low temperature, ramping annealing from low temperature, etc. are typical.

In the IG method described above, the outward diffusion of oxygen due to the heat treatment in the preceding stage is not sufficient in practice, and minute oxygen precipitates (such as BMD) may remain in the device active region. Further, since a plurality of heat treatment steps are required, practical application has not progressed so much due to workability problems and cost problems.

Recently, instead of the method requiring such multi-step heat treatment, 100% reducing gas or 100% is used.
By performing high-temperature heat treatment in an inert gas atmosphere or a mixed gas atmosphere of a reducing gas and an inert gas, a DZ layer is formed on the wafer surface and a BMD is formed on the bulk portion, and an intrinsic gettering effect (IG effect) is provided. Wafer manufacturing methods are also used. The applicant of the present invention relates to these production methods in JP-A-60-247935 and JP-A-61-19.
3458, JP-A-61-193459, JP-A-61
Nos. 193456, 62-123098, and 2-177541 are filed.

The typical heat treatment in a hydrogen atmosphere of this method is performed by the following temperature process. The temperature raising process for raising the temperature to the heat treatment temperature is from room temperature to 100
About 10 ℃ / min up to 0 ℃, from 1000 ℃ to 12 ℃
Up to 00 ° C, 3 ° C / min or less, heat treatment: about 1200 ° C
For more than 1 hour, the cooling process is from 1200 ℃ to 9 ℃
It is 3 ° C./min or less up to about 00 ° C. A typical temperature process is shown in FIG. In the heat treatment operation of FIG. 1, the temperature rising process is 10 ° C./min from room temperature to 1000 ° C.
3 ° C / min between 00 ° C and 1200 ° C, 1 heat treatment
1 hour at 200 ℃, cooling process from 1200 ℃ to 10 ℃
3 ° C / min up to 00 ° C, 10 ° C / m below 1000 ° C
I'm going in.

In this heat treatment operation, in the temperature raising process in the region of 1000 ° C. or higher, if the temperature raising rate is higher than about 3 ° C./min, slip may occur on the wafer being processed. In addition, the heat treatment furnace that is usually used has not been heated at a high speed because of heat insulation and restrictions of heating elements.

The mechanism of forming the wafer structure by the above heat treatment process can be estimated as follows. Since the temperature rising rate is slow during the temperature raising process, BMD growth occurs in the bulk portion, and at the same time, outward diffusion of oxygen occurs in the surface layer portion, and the oxygen concentration in the surface layer portion decreases. After reaching the heat treatment temperature, outward diffusion of oxygen in the surface layer portion is further performed, interstitial oxygen that becomes BMD nuclei in the surface layer portion is reduced, and disappearance of BMD in the surface layer portion is accelerated. In the bulk portion, oxygen is diffused in the wafer due to the high temperature heat treatment and BMD contraction occurs. However, since the amount of oxygen decrease is small, BMD disappears. Since the temperature rising rate is slow during the temperature lowering process, theoretically, BMD growth also occurs in the wafer surface layer portion, but oxygen in the surface layer portion is reduced by outward diffusion, so that BMD is not formed but becomes a DZ layer. On the other hand, BMD growth / precipitation occurs again in the bulk portion.

FIG. 2 shows a wafer in 100% hydrogen gas, and FIG.
The relation between the initial oxygen concentration of the wafer and the BMD density of the bulk portion of the wafer after the heat treatment when the heat treatment as shown in
Indicate. It is understood from FIG. 2 that the BMD density of the bulk portion after the heat treatment depends on the initial oxygen concentration of the wafer, and the BMD density of the bulk portion increases as the initial oxygen concentration increases.

In recent years, in order to improve the characteristics of a highly integrated memory device and the like, it is better to make the device active layer on the surface of a silicon wafer as a starting material defect-free because the metal mixed in during the device manufacturing process. It is more necessary and important than gettering impurities.

The initial oxygen concentration is high (1.6 × 10
¹⁸ atoms / cm ³ or more) As shown in FIG. 2, the number of wafers is 10 ⁹ / c in the conventional high temperature heat treatment in a reducing or inert gas.
A BMD of m ³ or more is formed. The wafer on which such a BMD is formed is excellent in terms of gettering effect of metal impurities, but if excessive BMD is formed, not only the mechanical strength of the wafer is lowered but also the device active layer or its vicinity is formed. However, since BMD is formed, the device characteristics may be deteriorated.

Due to such a situation, a wafer having a more perfect defect-free layer has recently been required, and therefore, the wafer has a lower oxygen concentration (1.4 × 10 ¹⁸ atoms / cm ^3).
However, such wafers are difficult to manufacture by conventional manufacturing methods and conditions, and there are many problems in terms of productivity and cost.

The present invention has been made in order to solve the above problems. Even in a wafer having a relatively high oxygen concentration range, the device active layer is more defect-free and the BMD of the bulk portion is BMD. Aims to provide a method for manufacturing a silicon wafer having a low density and such a silicon wafer.

[0017]

According to the first invention of the present application, the interstitial oxygen concentration [Oi] produced from a single crystal silicon ingot produced by the Czochralski method is 1.5 to 1.8. The heat treatment temperature of a silicon wafer of × 10 ¹⁸ atoms / cm ³ in a hydrogen gas atmosphere or a mixed gas atmosphere of hydrogen gas and an inert gas is set to 1100 ° C.
The heat treatment is performed at a temperature of 1300 ° C., a heat treatment time of 1 minute to 48 hours, and a temperature increase rate of 15 to 100 ° C./min in the temperature range of 1000 ° C. to 1300 ° C. during the heat treatment process. 10 μm
The BMD having a size of 20 nm or more is 10 ³
Has a defect-free layer which is the number / cm ³ or less, the oxygen precipitate density of the wafer inside the bulk portion [BMD] is, [BMD] ≧ 1 ×
10 ³ pieces / cm ³ and [BMD] ≦ exp {9.21
A gist of a method for manufacturing a silicon wafer is to manufacture a wafer having 0 × 10 ⁻¹⁸ × [Oi] +3.224} pieces / cm ³ . The second invention of the present application has an interstitial oxygen concentration [Oi] of 1.5 produced from a single crystal silicon ingot produced by the Czochralski method.
˜1.8 × 10 ¹⁸ atoms / cm ³ of a silicon wafer in a hydrogen gas atmosphere or in a mixed gas atmosphere of hydrogen gas and an inert gas at a heat treatment temperature of 1100 ° C. to 130 ° C.
0 ° C, heat treatment time 1 minute to 48 hours, 1 during heat treatment process
At least a depth of 10 from the wafer surface, which is produced by performing heat treatment at a temperature rising rate of 15 to 100 ° C./min in a temperature range of 000 ° C. to 1300 ° C.
1 BMD with a size of 20 nm or more over μm
Oxygen precipitate density [BMD] in the bulk portion inside the wafer has a defect-free layer of 0 ³ / cm ³ or less, and [BMD] ≧
1 × 10 ³ pieces / cm ³ , and [BMD] ≦ exp {9.
210 × 10 ^-18 × [Oi] +3.224} pieces / cm ³
The gist of the invention is a silicon wafer.

Further, all oxygen concentrations in this specification are Ol.
d It is a value based on a conversion coefficient according to ASTM.

Generally, the behavior of BMD during heat treatment of a wafer will be described.

According to the classical nucleation theory, BMD grows and contracts by attaching and detaching supersaturated oxygen with oxygen clusters as uniform nuclei.

Whether the BMD existing at a certain time point grows or shrinks / disappears depends on the size of the BMD at that time point and the critical nucleus radius determined by the temperature (and oxygen concentration) at that time point. Critical nucleus radius depends on temperature,
The critical nucleus radius increases with increasing temperature. When a wafer is held at a certain temperature, BMDs that have already grown larger than the critical nucleus radius at that temperature continue to grow, and BMDs having a diameter smaller than the critical nucleus radius contract and disappear.

Based on the above findings, the present inventors can realize the present invention by knowing that the BMD can be controlled by applying this to a wafer manufacturing method and a wafer suitable for manufacturing highly integrated devices can be manufactured. It is a thing.

The present invention is a region in which the oxygen concentration is relatively high, which is generally obtained in a silicon wafer manufactured from a silicon ingot manufactured by the ordinary Czochralski method, which is 1.5 to 1.8. × 10 ¹⁸ atoms / c
Applied for heat treatment of m ³ wafers. A wafer having an oxygen concentration lower than this can have a low BMD density without the heat treatment of the present invention as described above.

The heat treatment of the present invention is performed in a 100% hydrogen gas atmosphere or a mixed gas atmosphere of hydrogen gas and an inert gas. It is preferable to perform the treatment in a 100% hydrogen gas atmosphere from the viewpoints of forming a defect-free layer, facilitating outward diffusion of oxygen, and preventing surface roughness during heat treatment.

The heat treatment of the present invention is performed at 1100 ° C to 1300 ° C.
Done in. At 1100 ° C or lower, the effect of the present invention is not obtained, and at 1300 ° C or higher, the outward diffusion effect of oxygen is excellent, but there is a problem in safety and reliability of the device.

The heat treatment time of the present invention is 1 minute to 48 hours. If it is less than 1 minute, the effect of the present invention cannot be obtained, and if the heat treatment is performed for more than 48 hours, the effect cannot be expected to be improved.

During the heat treatment process of the present invention, the rate of temperature rise is 1 within the temperature range from 1000 ° C. to the heat treatment temperature.
It is necessary to raise the temperature at 5 to 100 ° C / min.

By setting the rate of temperature rise to 15 ° C./min in the range of 1000 ° C. or higher, the rate of increase of the critical nucleus radius described above can be made higher than the growth rate of the existing BMD at that temperature. it can. As a result, the critical nucleus radius becomes larger than the existing BMD diameter,
BMD does not grow, but tends to shrink. However, in reality, there is almost nothing that completely disappears during the temperature rising process because the time of the temperature rising process is short. The rate of temperature rise is preferably 20 ° C / min or more, more preferably 30 ° C / min
At the heat treatment temperature as described above, outward diffusion of oxygen progresses in the surface region, so that the oxygen concentration around the BMD near the surface becomes low and the disappearance further progresses to form the DZ layer. Even in the bulk part, BMD may progress in the direction of reduction and disappear. However, in the bulk part, there is little influence of the decrease in oxygen concentration due to the outward diffusion of oxygen, and the BMD
Is reduced, the concentration of dissolved oxygen dissolved around the BMD is increased, so that it takes time to completely disappear.

During the temperature lowering process, it is considered that the BMD does not grow so much even if the temperature lowering rate is changed because the size and density of BMD and the oxygen concentration in the surface layer portion are already small. However, the temperature lowering rate is preferably 2 to 300 ° C./min in view of productivity, wafer quality (preventing occurrence of slippage and surface roughness), structural problems of the furnace used, and the like.

By performing such heat treatment, the initial oxygen concentration is 1.5 to 1.8 × 10 ¹⁸ atoms / cm 3.
10μ from the wafer surface using ³ silicon wafer
BMD with a size of 20 nm or more over a depth of m or more
Has a DZ layer of less than 10 ³ / cm ³ and D
BMD density [BMD] of bulk part in region deeper than Z layer ≧
1 × 10 ³ pieces / cm ³ or more and [BMD] ≦ exp
A wafer having {9.210 × 10 ⁻¹⁸ × [Oi] +3.224} can be manufactured.

Such a wafer is indicated by the area A + B + C in the graph of FIG.

A wafer having an initial oxygen concentration as described above, which has a good DZ layer on the surface layer and B of the bulk portion.
Conventionally, there is no wafer whose MD density is within the above range,
It is provided for the first time by the present invention.

A more preferable range of BMD density is as follows.
1 × 10 ³ ≦ [BMD] ≦ 1 × 10 ⁸ and [BMD]
≤ exp {9.210 × 10 ^-18 × [Oi] +3.22
4} / cm ³ (region B + C in FIG. 2), and more preferably [BMD] ≦ exp {5.757 × 10 ⁻¹⁸
× [Oi] +3.224} / cm ³ (region C in FIG. 2).

A wafer having a BMD density in such a range has a gettering function, and the device active layer as the surface layer is a good defect-free DZ layer and the mechanical strength is not lowered.

The BMD in the DZ layer of the surface layer portion is preferably substantially 0. The reason why the BMD in the DZ layer is defined as described above is that the detection limit of the BMD size of the present device is 20 nm, and when the BMD density exceeds 10 ³ pieces / cm ³ , it is no longer defective. This is because the characteristics of the manufactured device are adversely affected.

[0036]

EXAMPLES Hereinafter, the wafers used for explaining the examples of the present invention were all silicon wafers cut from a silicon ingot pulled up by the Czochralski method, manufactured by a usual method, and subjected to mirror finishing. These wafers are N type, plane orientation (100),
Specific resistance 1 to 1000 Ω / cm, initial interstitial oxygen concentration [O
i] is 1.45 to 1.74 × 10 ¹⁸ atoms / cm ³
Is.

Further, the furnace used has improved heat insulation, and the amount of heat generated by the heating source is increased. For example, an infrared heating type furnace was used.

Example 1 Among the above wafers, [Oi] was 1.70 × 10 ¹⁸ ato.
1 ms / cm ³ wafer in 100% hydrogen gas atmosphere
Heat treatment was performed at 200 ° C. for 1 hour. However, 1000 ° C
To 1200 ° C., the temperature rising rate was 30 ° C./min, and the temperature lowering rate was 300 ° C./min.

Example 2 Heat treatment was performed under the same conditions as in Example 1 except that a wafer having [Oi] of 1.61 × 10 ¹⁸ atoms / cm ³ was used.

Example 3 Heat treatment was performed under the same conditions as in Example 1 except that a wafer having [Oi] of 1.51 × 10 ¹⁸ atoms / cm ³ was used.

Example 4 A temperature rising rate in the range of 1000 ° C. to 1200 ° C. was 30 ° C. /
The heat treatment was performed under the same conditions as in Example 1 except that the temperature was set to min and the temperature lowering rate was set to 3.8 ° C./min.

Example 5 A temperature rising rate in the range of 1000 ° C. to 1200 ° C. was 30 ° C. /
Heat treatment was performed under the same conditions as in Example 1 except that the temperature was set to min and the rate of temperature decrease was 30 ° C./min.

Comparative Example 1 Among the above wafers, [Oi] was 1.51 × 10 ¹⁸ ato
1 ms / cm ³ wafer in 100% hydrogen gas atmosphere
Heat treatment was performed at 200 ° C. for 1 hour. However, 1000 ° C
To 1200 ° C., the heating rate is 6.3 ° C./min,
The temperature lowering rate was 10 ° C./min.

Comparative Example 2 Among the above wafers, [Oi] was 1.61 × 10 ¹⁸ ato
1 ms / cm ³ wafer in 100% hydrogen gas atmosphere
Heat treatment was performed at 200 ° C. for 1 hour. However, 1000 ° C
To 1200 ° C., the heating rate is 6.3 ° C./min,
The temperature lowering rate was 10 ° C./min.

Comparative Example 3 Among the above wafers, [Oi] was 1.70 × 10 ¹⁸ ato.
1 ms / cm ³ wafer in 100% hydrogen gas atmosphere
Heat treatment was performed at 200 ° C. for 1 hour. However, 1000 ° C
To 1200 ° C, the heating rate is 3.8 ° C / min,
The temperature lowering rate was 3.8 ° C./min.

Comparative Example 4 Among the above wafers, [Oi] was 1.70 × 10 ¹⁸ atoms.
1 ms / cm ³ wafer in 100% hydrogen gas atmosphere
Heat treatment was performed at 200 ° C. for 1 hour. However, 1000 ° C
To 1200 ° C, the heating rate is 3.8 ° C / min,
The temperature lowering rate was 300 ° C./min.

Comparative Example 5 Among the above wafers, [Oi] was 1.50 × 10 ¹⁸ ato.
1 ms / cm ³ wafer in 100% hydrogen gas atmosphere
Heat treatment was performed at 200 ° C. for 1 hour. However, 1000 ° C
To 1200 ° C. in the range of 2 to 3 ° C./min,
The rate of temperature decrease was 2-3 ° C / min.

Comparative Example 6 Among the above wafers, [Oi] was 1.56 × 10 ¹⁸ ato
1 ms / cm ³ wafer in 100% hydrogen gas atmosphere
Heat treatment was performed at 200 ° C. for 1 hour. However, 1000 ° C
To 1200 ° C. in the range of 2 to 3 ° C./min,
The rate of temperature decrease was 2-3 ° C / min.

Comparative Example 7 Among the above wafers, [Oi] was 1.60 × 10 ¹⁸ ato
1 ms / cm ³ wafer in 100% hydrogen gas atmosphere
Heat treatment was performed at 200 ° C. for 1 hour. However, 1000 ° C
To 1200 ° C. in the range of 2 to 3 ° C./min,
The rate of temperature decrease was 2-3 ° C / min.

Comparative Example 8 Among the above wafers, [Oi] was 1.74 × 10 ¹⁸ atoms.
1 ms / cm ³ wafer in 100% hydrogen gas atmosphere
Heat treatment was performed at 200 ° C. for 1 hour. However, 1000 ° C
To 1200 ° C. in the range of 2 to 3 ° C./min,
The rate of temperature decrease was 2-3 ° C / min.

Comparative Example 9 Among the above wafers, [Oi] was 1.45 × 10 ¹⁸ ato
1 ms / cm ³ wafer in 100% hydrogen gas atmosphere
Heat treatment was performed at 200 ° C. for 1 hour. However, 1000 ° C
To 1200 ° C, the heating rate is 8.5 ° C / min,
The temperature lowering rate was 3.8 ° C./min.

The densities of BMDs produced by the infrared tomography method were measured from the cross section ((110) plane) of the heat-treated wafers of these Examples and Comparative Examples. The minimum detectable BMD size in the infrared tomography method used is 20 nm. This method depends on the measurement area
The detection limit of D density is different. In this measurement, the measurement was performed in a rectangular parallelepiped region having a depth of 185 μm and a surface of 4 × 200 μm. The measurement limit of the BMD density in this case is 6.
It is 8 × 10 ⁶ pieces / cm ³ . Under such conditions, the thickness of the DZ layer having a size of 20 nm or more and having a BMD size of 10 ³ pieces / cm ³ or less, which is defined in the present invention, is the first time in a typical field of view that the BM
D corresponds to the depth from the surface where it is detected.

The measurement results are shown in Tables 1 and 2 together with the heat treatment conditions.
Shown in. FIG. 2 is a graph showing the relationship between the initial oxygen concentration of the wafer and the BMD density.

[0054]

[Table 1]

[Table 2] As is clear from Tables 1 and 2, and FIG. 2, the wafer subjected to the heat treatment of the present invention has a good DZ layer formed even if the initial oxygen concentration [Oi] is high, and further formed in the bulk portion. The BMD can have a low density. That is, it has a defect-free layer having a BMD of 10 ³ pieces / cm ³ or less having a size of 20 nm or more at least 10 μm or more deep from the surface, and the oxygen precipitate density [BMD] of the wafer internal bulk part is [BMD ] ≧ 1 × 10 ³ pieces / c
m ³ , and [BMD] ≦ exp {9.210 × 10 ⁻¹⁸
Wafers of × [Oi] +3.224} / cm ³ can be manufactured.

On the other hand, as can be seen from the comparative example, it can be seen that the wafers that have been subjected to the heat treatment under the conditions outside the scope of the present invention form more BMD as the initial oxygen concentration increases. In the comparative example, although the defect-free layer is formed, a large amount of BMD is formed in the bulk portion inside the wafer, and a large amount of BMD is also formed in the vicinity of the defect-free layer on the surface.
As a result, B is formed on the surface of the wafer near the device active layer.
The presence of MD adversely affects the characteristics of the manufactured device. In addition, the mechanical strength of the wafer is also reduced.

Since the wafer of the present invention is constructed as described above, the device active layer is defect-free, and the BMD in the vicinity of the active layer is small, so that devices having good characteristics can be manufactured with high yield. it can.

In the heat treatment of the present invention, the temperature raising process,
It is preferable to perform the heat treatment and the temperature lowering process in the same gas atmosphere, but the composition of the atmosphere gas may be changed in each case. However, the heat treatment needs to be performed in a hydrogen gas atmosphere or a mixed atmosphere of hydrogen gas and an inert gas.

[0058]

According to the present invention, the BMD density formed even on a wafer having a high initial oxygen concentration can be lowered, so that a highly integrated device having good characteristics can be manufactured with a high yield. Further, such a wafer can be provided. Further, even a wafer having a high oxygen concentration can be used as a wafer suitable for manufacturing highly integrated devices, so that the yield of wafers can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a temperature process of conventional heat treatment.

FIG. 2 is a diagram showing the relationship between the initial oxygen concentration of a wafer and the BMD density after heat treatment.

Front page continuation (72) Inventor Kashima Hitotsu, Soya 30 Hadano City, Kanagawa Prefecture, Toshiba Ceramics Co., Ltd.Development Laboratory (72) Inventor Yoshio Kirino 30 Soya, Hadano City, Kanagawa Prefecture, Toshiba Ceramics Co.

Claims (2)

[Claims] 1. An interstitial oxygen concentration [Oi] produced from a single crystal silicon ingot produced by the Czochralski method is 1.5 to 1.8 × 10 ¹⁸ atoms / cm ^3.
The silicon wafer of No. 1 is heated at a heat treatment temperature of 1 in a hydrogen gas atmosphere or a mixed gas atmosphere of hydrogen gas and an inert gas.
The heat treatment is performed at a temperature of 100 ° C. to 1300 ° C., a heat treatment time of 1 minute to 48 hours, and a temperature rising rate of 15 ° C. to 100 ° C./min in the temperature range of 1000 ° C. to 1300 ° C. during the heat treatment process. B having a size of 20 nm or more over at least 10 μm in depth
The wafer has a defect-free layer having an MD of 10 ³ pieces / cm ³ or less, and the density of oxygen precipitates [BMD] in the bulk portion inside the wafer is [BMD]
MD] ≧ 1 × 10 ³ pieces / cm ³ and [BMD] ≦ ex
A method of manufacturing a silicon wafer, which comprises manufacturing a wafer having p {9.210 × 10 ⁻¹⁸ × [Oi] +3.224} / cm ³ . 2. The interstitial oxygen concentration [Oi] produced from a single crystal silicon ingot produced by the Czochralski method is 1.5 to 1.8 × 10 ¹⁸ atoms / cm ^3.
The silicon wafer of No. 1 is heated in a hydrogen gas atmosphere or a mixed gas atmosphere of hydrogen gas and an inert gas at a heat treatment temperature of
It is manufactured by performing a heat treatment at a temperature of 100 to 1300 ° C., a heat treatment time of 1 minute to 48 hours, and a heating rate of 15 to 100 ° C./min in a temperature range of 1000 to 1300 ° C. during the heat treatment process. The size is 20n at least from the wafer surface to a depth of 10 μm or more.
The density of oxygen precipitates in the bulk part inside the wafer [BM has a defect-free layer in which the BMD of m or more is 10 ³ / cm ³ or less.
D] is [BMD] ≧ 1 × 10 ³ pieces / cm ³ and [B
MD] ≦ exp {9.210 × 10 ⁻¹⁸ × [Oi] +
3.224} / cm ³ silicon wafer.