JP2002118114A - Silicon wafer and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a silicon wafer where there are no grown-in and oxygen sludge defects and no slits in the activation region of a surface layer, and the existence density of the internal oxygen sludge is large, and to provide a method for manufacturing the silicon wafer. SOLUTION: In this silicon wafer, oxygen sludge density at the internal bulk section is set to 5×105/cm or more, and the number of the grown-in defects with a size of at least 0.09 μm is set to 1.6×10-2/cm2 or less in an arbitrary surface in parallel with a surface at a range from the surface that becomes an active region to a depth of 10 μm. In the method for manufacturing the wafer, the content of nitrogen is set to 1×1013 to 5×1015 atoms/cm3, dispensing is carried out from a silicon single crystal grown by setting a pulling speed to at least 1.2 mm/min, a heat-up temperature in heat treatment in hydrogen atmosphere is set to 60 deg.C/min or less, 10 deg.C/min or less, and 2 deg.C/min or less when temperature is set to 1000 deg.C or less, exceeds 1000 deg.C and is equal to 1100 deg.C or less, and exceeds 1100 deg.C, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer for forming an integrated circuit obtained from a silicon single crystal, which is used as a semiconductor material, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Silicon wafers used for devices such as semiconductor integrated circuits are mainly manufactured by the Czochralski method (C
Z method). In the CZ method, a single crystal is grown by immersing a seed crystal in molten silicon in a quartz crucible and pulling it up. However, with the progress of the silicon single crystal pulling and growing technique, a large number of dislocation-free large single crystals has been developed. Crystals are to be produced.

[0003] Semiconductor devices are manufactured as products through a number of processes using wafers obtained from single crystals as substrates. In the process, the substrate is subjected to a number of physical, chemical, and thermal treatments, including treatments in harsh thermal environments, such as high-temperature treatments exceeding 1100 ° C.
For this reason, even if it is not found in the state in which the single crystal is manufactured as it is, it becomes apparent during the manufacturing process of the device, and may cause oxygen precipitates that may result in a decrease in the performance. Lattice defects, which have a large effect on the temperature, that is, grown-in defects and the like become a problem.

This wafer manufactured by the CZ method usually contains 10 ¹⁸ atoms / cm 2 by mixing from a quartz crucible or the like.
Contains about ³ oxygen. This oxygen is added to the BMD (Bulk
Fine precipitates mainly composed of oxides referred to as microdefects are generated, and these have useful effects such as exhibiting a gettering action of heavy metal impurities. However, deposition on a portion where a device is formed on a wafer, that is, a device activation region, impairs the performance of the device. For this reason, heat treatment at a high temperature of 1100 to 1200 ° C. is performed to lower the oxygen concentration near the surface to below the precipitate generation limit, and to precipitate inside but not to the device activation region on the surface. The method has been adopted.

[0005] If grown-in defects are present in the activated region, a device with sufficient performance cannot be obtained even if oxygen precipitates can be suppressed. Grown-in defects (C
OP: Crystal Originated Particle, etc.) and dislocation cluster type defects. In general, when the growth rate of a single crystal is high, a cavity type defect is generated, and when the growth rate is low, dislocation cluster defects are likely to occur. . When dislocation cluster-type defects occur, device characteristics are hindered and non-defective products cannot be obtained.In addition, under conditions where these defects are highly likely to occur, single crystal growth speed is slow and productivity is poor. A single crystal is grown in a region where defects are likely to occur. However, this hollow defect is
When the device pattern becomes finer, the withstand voltage characteristic of the thinned gate oxide film is greatly deteriorated, which makes it difficult to cope with high integration.

[0006] On the other hand, it is known that when a heat treatment is performed on a wafer in a hydrogen atmosphere, cavity defects are eliminated or reduced, and the withstand voltage characteristics of the gate oxide film are improved. The effect of the heat treatment in the hydrogen atmosphere seems to be affected by the growth conditions of the silicon single crystal. For example, in the invention disclosed in Japanese Patent Application Laid-Open No. 10-208987, when growing the single crystal, the temperature of 1150 to 1080 ° C. 2.0 ° C / mi cooling rate in temperature range
By setting n or more, the generation density of cavity-shaped defects in a single crystal is increased, and thereby the defect disappearance rate during heat treatment of the wafer in hydrogen is increased.

Japanese Patent Application Laid-Open No. 11-186277 discloses that the growth rate is set to 0.6 mm / min or more and the oxygen concentration is set to 16 ppma (0.8 × 10 ¹⁸ at
oms / cm ³ ) The size of COP was reduced to 60-130 nm or less.
Discloses a method of manufacturing a defect-free silicon wafer in which a wafer obtained from a silicon single crystal is subjected to a heat treatment at 1200 ° C. or more in a reducing atmosphere containing hydrogen.

As described above, as a method for controlling the production conditions of a single crystal to change the generation distribution of hollow defects such as COP and heat-treating a wafer to reduce the number of defects, Japanese Patent Application Laid-Open No. Hei 10-98047 discloses a method in which nitrogen is contained. Was disclosed in the official gazette. In this case, nitrogen was added to the single crystal having an oxygen concentration of 0.4 × 10 ¹⁸ / cm ³ or more at 1 × 10 ¹⁸
By including ¹⁴ / cm ³ or more, in particular without controlling the cooling during the growth of the single crystal, a state in which equivalent to that rapid cooling to 850 to 1100 ° C., small defects distributed more,
It is said that the single crystal wafer can be easily reduced in defects by heat treatment at 1000 ° C. or more for 1 hour or more. (Note that the element concentrations in this publication are 0.4 × 10 ¹⁸ / cm ³ and 1
× 10 ¹⁴ / cm ³ etc., but these are 0.4 × 10
It is estimated that it should be displayed at ¹⁸ atoms / cm ³ or 1 × 10 ¹⁴ atoms / cm ³ . It is also disclosed in Japanese Patent Application Laid-Open No. H11-189493 that addition of nitrogen changes the distribution of oxygen precipitates. According to the present invention, when growing a single crystal containing a normal amount of oxygen of about 10 ¹⁸ atoms / cm ³ , if nitrogen is contained at 10 ¹³ atoms / cm ³ or more, an OSF (Oxidation-induced Stacking Fault:
Since oxygen precipitates serving as nuclei of oxygen-induced stacking faults are distributed uniformly and at high density, the single crystal is used as a base material for an epitaxial wafer having a large gettering effect on impurities.

As described above, the addition of nitrogen greatly affects the distribution and size of oxygen precipitates, cavity defects, and the like that are formed during the single crystal growth stage and become apparent due to the subsequent thermal history. It is clear that this is,
The presence of nitrogen has the effect of finely and evenly dispersing nuclei inside the single crystal that cause these defects, thereby accelerating and increasing the effect of heat treatment. Seem.

Japanese Patent Application Laid-Open Nos. 11-322490 and 11-322490 disclose a method in which a single crystal is produced by adding nitrogen, and an activated region having few defects is formed in the surface layer by heat-treating the obtained wafer. It is disclosed in Japanese Patent No. 322491. In these inventions, the concentration of nitrogen to be added is 1 × 10 ¹⁰ to 1 × 10 ¹⁵ at.
A single crystal having an oxygen concentration of 1.2 × 10 ¹⁸ atoms / cm ³ or less as oms / cm ³ is grown, and a wafer obtained therefrom is treated with an oxygen, hydrogen, argon or a mixed atmosphere thereof at 900.
The heat treatment is performed at a temperature of not less than ° C. and not more than the melting point of silicon to form an active region with low COP defects on the surface. In the invention of Japanese Patent Application Laid-Open No. 11-322490, the heat treatment temperature is 1100 ° C. or higher and heating is performed for 1 to 60 seconds by rapid heating and rapid cooling.
In the invention of Japanese Patent No. 2491, the example is heating at 1000 ° C. for 10 hours.

As described above, a single crystal containing a suitable amount of oxygen is grown by adding nitrogen, and an appropriate heat treatment is applied to a wafer obtained from the single crystal. However, it is presumed that a wafer having an active region with few defects on the surface may be easily obtained. However, it is difficult to say that a wafer having a sufficient gettering sink inside the wafer and having very few defects in the surface layer, and an efficient manufacturing method for obtaining the wafer have not been sufficiently established.

[0012]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a cavity type defect, that is, a grown-in defect (hereinafter referred to as a grown-in defect), an oxygen precipitate defect in an activated region from the surface to a depth exceeding 10 μm. Another object of the present invention is to provide a silicon wafer and a method for producing the same, which have no slip and have a sufficiently high BMD or oxygen precipitate density serving as a gettering sink in a bulk portion.

[0013]

Means for Solving the Problems The present inventors have conducted various investigations on the effect of changing the size and distribution of grown-in defects and oxygen precipitate defects in a grown silicon single crystal due to the nitrogen content, and obtained the results. The possibility of improving the performance of the used wafer or rationalizing the manufacturing conditions was examined.

As a result, it was first confirmed that addition of nitrogen reduces the size of grown-in defects and increases the distribution density of oxygen precipitates, and is uniformly dispersed, as previously known. Was done. Next, when examining the effect of the growth rate of the single crystal, it was found that the gr
Although own-in defects tend to be small, it was found that the effect was particularly remarkable when nitrogen was added.

One of the purposes of heat-treating a wafer is to eliminate minute defects and to diffuse impurities. However, if the existing form of these defects and impurities before the heat treatment changes, the effect of the heat treatment may be different. Therefore, using a wafer obtained from a single crystal in which the nitrogen is added and the pulling rate is increased, a DZ (Denuded Zone) having no defect on the surface is formed, and the grown DZ is formed.
Various heat treatment conditions for obtaining a defect-free layer having no n-defects and conditions for increasing the effective BMD inside were examined.

[0016] Microscopic defects having a hollow shape such as COP shrink and disappear when heated to a high temperature in an atmosphere containing hydrogen. On the other hand, the formation of DZ requires a multi-step heat treatment, that is, high temperature (> 1100
C.) in a non-oxidizing atmosphere, effective precipitation nucleation at a low temperature (600 to 750 ° C.), and bulk defect formation at an intermediate temperature.

On the other hand, when the removal of hollow minute defects and the formation of DZ were examined on a single crystal wafer to which the above-mentioned nitrogen was added and the pulling rate was increased, the rate of temperature rise was increased in a hydrogen atmosphere. It was found that heat treatment of increasing the temperature to a not so high temperature also formed DZ having no defect in the surface layer.

This is because, as described above, by adding nitrogen and growing a single crystal at a high pulling rate, grown-in defects are refined, while nuclei such as relatively large oxygen precipitates are formed. It was presumed that this was due to uniform formation within the single crystal. In general, as the size of the fine particles present in the bulk is the same, the smaller the size, the more easily the precipitation, disappearance, coalescence, growth and the like proceed. This is because the activity increases when the ratio of surface area to volume is large.

If attention is paid only to the formation of DZ on the surface layer, it seems that the wafer made of this nitrogen-added single crystal can be rapidly heated. However, as the study of utilizing the short-time heat treatment by the rapid heating is further advanced, it has been found that defects such as slip are easily generated by dislocation, and that the BMD inside the wafer is insufficiently formed.

When the temperature is increased quickly, the temperature difference between the outer peripheral portion and the central portion of the wafer tends to increase during the temperature increase. Due to the stress caused by the difference in thermal expansion based on the temperature, defects due to dislocation such as slip may occur. It is easy to occur. Such a slip tends to be suppressed in a single crystal in which nitrogen is added and the pulling rate is increased, but it is still not preferable to increase the temperature increasing rate, and there is a limit to the rate improvement.

In addition, the formation of BMD is insufficient because
It was presumed that the rapid heating resulted in too short a time for passing through a temperature range in which oxygen precipitates were easily formed, which would make it difficult for oxygen to precipitate. Therefore, as a result of various investigations on conditions under which no slip occurs and BMD is sufficiently formed, it has been found that it is effective to control the temperature rising rate in accordance with the temperature range.

The ultimate temperature of the heat treatment is determined by the growth of the wafer.
Depending on the size of the n-in defect and its size, it is necessary to appropriately select the DZ in order to sufficiently form the DZ. However, no slip occurs regardless of the temperature reached, and B
It has been found that in order to increase the MD, the upper limit of the heating rate may be determined according to the temperature range.

The minimum required holding time after reaching the target temperature becomes shorter as the temperature becomes higher. In order to improve the productivity of the heat treatment, it is necessary to shorten the heating time and the holding time.

Based on the above findings, the present invention was completed by further clarifying the limitations of the respective conditions. The gist of the present invention is as follows. (1) The oxygen precipitate density in the bulk portion inside the wafer is 5 × 10 ⁵ / cm ² or more, and the depth from the surface to be the active region is 10
A silicon wafer characterized in that the number of grown-in defects of 0.09 μm or more is 1.6 × 10 ⁻² / cm ² or less in a range up to μm. (2) Heat treatment in a hydrogen atmosphere using a wafer cut from a silicon single crystal grown with a nitrogen content of 1 × 10 ^{13 to} 5 × 10 ¹⁵ atoms / cm ³ and a growth rate of 1.2 mm / min or more. The temperature rise rate when applying is 60 ° C / min or less in the temperature range of 1000 ° C or less, and in the temperature range of over 1000 ° C and 1100 or less.
(1) The method for producing a silicon wafer according to the above (1), wherein the temperature is set to 2 ° C / min or less in a temperature range of 10 ° C / min or less and 1100 ° C or more. (3) When the heating temperature of the heat treatment is T ° C., the temperature is maintained for at least a time satisfying the following expression.
(2) The method for manufacturing a silicon wafer.

Holding time (seconds) ≧ 10 ⁻¹⁰ × exp {40000 / (T + 273)}

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The silicon wafer of the present invention
In the range from the plane to a depth of 10 μm,
For grown-in defects with a size of 0.09 μm or more on any surface
Number is 1.6 × 10 ^-2Pieces / cm^TwoLess than and bulk inside
In some areas, the detected density of oxygen precipitates
5 × 10^FivePieces / cm^TwoThat is all.

The limitation of the number of defects in the range from the surface to a depth of 10 μm is that the active region, that is, the surface portion where the device is formed is within 10 μm, and the growth-in
This is because if the number of defects is 1.6 × 10 ⁻² / cm ² or less, it is considered that there is substantially no defect, which is equivalent. In addition, the reason why the size of the defect is 0.09 μm or more is that even if the size is less than 0.09 μm, it does not affect the performance degradation of the device, so that it can be detected stably at present. This is because the size is almost the lower limit.

On the other hand, in the inner bulk portion, it is preferable that the amount of oxygen precipitates or BMDs serving as sink sites for gettering of heavy metal contamination is large and uniform, and if it is 5 × 10 ⁵ / cm ² or more, Deemed sufficient.
Since the detection of oxygen precipitates is performed on the cleavage plane of the cross section of the wafer, the abundance is indicated by the detection density on the observation plane. In this case, a commonly adopted method is to split the wafer to obtain a {110} cleavage plane, perform etching with a light solution, and obtain the deposition density on this plane.

In the production of the above wafer, the nitrogen content is
A wafer cut from a silicon single crystal grown at 1 × 10 ^{13 to} 5 × 10 ¹⁵ atoms / cm ³ at a growth rate of 1.2 mm / min or more is used. When the nitrogen content is set to 1 × 10 ¹³ atoms / cm ³ or more, if the value is below this value, the pulling speed is set to 1.2 mm / min.
This is because the effect of reducing the size of the grown-in defect, which is obtained when the speed is increased as described above, is not sufficient. In addition, since polycrystallization tends to occur when the nitrogen content increases, it is preferable to set the nitrogen content to at most 5 × 10 ¹⁵ atoms / cm ³ .

In order to sufficiently exhibit the effect of reducing grown-in defects by adding nitrogen, the pulling speed should be 1.2 mm /
It is preferred to be at least min. The higher the pulling speed, the smaller the grown-in defects can be.There is no particular upper limit, but in order to produce a stable and sound single crystal,
The pulling speed is preferably up to about 2.5 mm / min.

Using a wafer cut out of the silicon single crystal thus obtained, the rate of temperature rise when heat treatment in a hydrogen atmosphere is performed is 60 ° C./min or less in a temperature range of 1000 ° C. or less, and 1000 ° C. or less. In the temperature range above ℃ and below 1100
10 ° C / min or less, 2 ° C / min or less in the temperature range exceeding 1100 ° C.

The hydrogen atmosphere is used to suppress oxidation of the wafer, promote desorption of oxygen and nitrogen from the surface, and facilitate formation of DZ on the wafer surface. Hydrogen is preferably of high purity, but may be a substantially hydrogen atmosphere in which helium, argon, or the like is mixed.

The upper limit of the heating rate is determined according to the temperature range in order not to cause slip and to sufficiently generate BMD. Once the slip occurs, it does not disappear even if the temperature is increased, so it is necessary to set the upper limit of the heating rate in each temperature range. In addition, the situation of BMD generation in each temperature range is different, for example, when heated at a temperature rise rate exceeding 60 ° C / min in a temperature range up to 1000 ° C, then in a temperature range exceeding 1000 to 1100 ° C and 1100 ° C Even when the heating rate is in the above range, the density is not sufficient.

The upper limit of the heating rate is limited as described above, but the lower limit is not particularly defined. This is because the effect of the present invention can be obtained as long as the heating rate is within the above range in each temperature range, and the effect does not change even if each heating rate is made slower. Therefore, slowing down simply causes an increase in the processing time, and saves some heating energy, but does not provide any other benefit. preferable.

The value of the heating rate may be an average value in the temperature range. In normal heating, the rate of temperature rise is high in a low temperature range and is low in a high temperature range. Therefore, if the average rate of temperature rise is regulated, the intended effect can be obtained. In addition, the above 60 ℃ in the temperature range up to 1000 ℃
The heating rate of not more than / min may be after the temperature exceeds 700 ° C. The heating rate in the temperature range up to 700 ° C. has almost no effect on the characteristics of the wafer.

The temperature of the heat treatment in hydrogen is desirably 1000 to 1250 ° C. The number of grown-in defects in DZ decreases as the heating temperature increases, but heating above 1250 ° C increases the heat load of the heat treatment furnace and significantly increases the cost of the furnace internal structure. This is because heating at less than 1000 ° C. does not sufficiently reduce the number of defects.

Nitrogen is contained in the wafer before processing in a hydrogen atmosphere.
What is necessary is just to contain at 1 × 10 ^{13 to} 5 × 10 ¹⁵ atoms / cm ³ ,
There is no particular restriction on the amount contained in the processed wafer. This is mainly because in the process of reaching the predetermined heating temperature, the surface layer is made defect-free and oxygen precipitates are formed inside.

The holding time after reaching the target temperature T (° C.) satisfies the following. Retention time (sec) ≧ 10 ⁻¹⁰ × exp {40000 / (T + 273)}... This is because at low temperatures, the desired DZ is formed and the number of grown-in defects there is reduced. This is because the longer the holding time is, the shorter the temperature is. As long as the above expression is satisfied, the holding time may be long. However, no further effect can be expected even if it is maintained for a long time, and it only wastes heating energy and deteriorates productivity.

The cooling conditions after holding at a high temperature are not particularly limited since the state of the defect distribution and the like is substantially determined in the process of raising the temperature. However, rapid cooling is not preferred because it may affect the occurrence of slip, and it is desirable that cooling be performed in a time of 30 minutes or more.

[0040]

[Embodiment 1] The oxygen concentration for obtaining an 8-inch wafer having a p-type resistance value of 1 to 10 Ωcm is 1.1 to 1.3 ×.
A single crystal of 10 ¹⁸ atoms / cm ³ or less was grown at a pulling rate of 1.0 mm / min while changing the nitrogen concentration. A wafer having a thickness of 0.7 mm was prepared from the obtained single crystal, and the size of the grown-in defect was measured by the scattering intensity of infrared laser light. This measurement was performed using a calibration curve prepared in advance by measuring the size of a defect by directly observing a defect with a transmission electron microscope using several wafers and obtaining the scattering intensity on the same wafer. In this case, the defect was regarded as a sphere and its diameter was made large. Defect size can be determined arbitrarily on a wafer taken from a single crystal manufactured under the same conditions except for the amount of nitrogen.
1000 locations were selected and the size of detected grown-in defects was averaged. FIG. 1 shows the relationship between the obtained nitrogen addition amount and the average diameter of defects.

As is apparent from this figure, the nitrogen concentration in the single crystal, the average value of the size of grown-in defects as higher decreases, the particular becomes 1 × 10 ¹³ atoms / cm ³ or more, significantly defects It can be seen that the diameter becomes smaller. The nitrogen concentration is
If it exceeds 5 × 10 ¹⁵ atoms / cm ³ , polycrystallization tends to occur.

Next, when nitrogen is not added, 1 × 10 ¹² atoms
/ cm ³ when the addition and 1 × 10 ¹⁴ to atoms / cm ³ 3 kinds of single crystals of adding grown by changing the pulling rate was examined an average size of grown-in defects in the same manner as described above . FIG. 2 shows the results. In each case, the defect size decreases as the pulling speed increases. Nitrogen is 1 × 10 ¹² atoms
/ cm ³ does not differ from the case where nitrogen is not added, but in the case of a single crystal in which nitrogen is added at 1 × 10 ¹⁴ atoms / cm ³ , the size of a defect is about half of that in the case where nitrogen is not added. Has become.
In order to sufficiently exert the effect of adding nitrogen, it is determined that the pulling speed is preferably set to 1.2 mm / min or more.

Example 2 The same 8-inch single crystal as in Example 1 described above was used. A: The pulling speed was 2.0 mm / min without adding nitrogen. B: The pulling speed was 1 × 10 ¹⁴ atoms / cm ^{3 of} nitrogen. 1.0mm /
min C: Nitrogen is added at 1 × 10 ¹⁴ atoms / cm ³ and the pulling speed is 1.2 mm /
min D: Nitrogen is added at 1 × 10 ¹⁴ atoms / cm ³ and the pulling speed is 2.0 mm /
Four types were grown as min, and a wafer having a thickness of 0.7 mm was cut out from each single crystal, and the following investigation was performed.

Using a vertical batch type furnace, 700-1000 ° C. at 5 ° C./min and 1000-1100 ° C. at 1 ° C./mi in a high-purity hydrogen atmosphere.
n 、 1100 ~ 1200 ℃ 0.5 ℃ / min
Hold for hours. Temperature rises from normal temperature to 1200 ° C over 6 hours,
Hold for 1 hour. After cooling, the wafer surface is polished from the surface in 5 μm increments, and the polished surface is grown-in with a size of 0.09 μm or more using a surface inspection device (SP-1 manufactured by KLA-Tencor) using light scattering by an infrared laser. The number of defects was measured.

FIG. 3 shows the number of defects per cleaved surface measured at a depth position from the surface. As is clear from the above, the wafer using a single crystal of A or the wafer using a single crystal of B has an increased number of defects as it goes from the surface to the inside, but the nitrogen content within the condition range of the present invention is 1 ×. 10 ¹⁴ ato
ms / cm ³ added and the pulling speed is 1.2mm / min.
In a wafer made of D single crystal of 2.0 mm / min, not only the number of defects on the surface is small, but also the number of defects does not increase even if it goes inside, and the number of defects in the activated region is sufficiently low. Understand.

[Embodiment 3] Each wafer taken from the four single crystals of A, B, C and D in the above Embodiment 2 was heated at a temperature rising rate of 1000 ° C. or less (700 ° C. or less) in a hydrogen atmosphere.
° C), above 1000 ° C to 1100 ° C, and above 1100 ° C to 1200 ° C
After the temperature reached the target processing temperature, cooling was performed for one hour or after maintaining the time determined by the above formula.

After cooling, the presence or absence of slip by the X-ray topography method of the wafer, the number of grown-in defects having a size of 0.09 μm or more at a depth of 10 μm, and
Oxygen precipitate (B
Investigations on the precipitation density on this surface of MD) were conducted.

Table 1 summarizes the heat treatment conditions for the wafer and the results of the examination of the obtained wafer. First, sample numbers 1 to 8 or 9 to 16 obtained from a single crystal of A to which nitrogen was not added or a single crystal of B having a pulling speed of 1.2 mm / min or less as defined in the present invention even when nitrogen was added. Under the wafer heat treatment conditions defined in the present invention, a wafer having no slip, a small number of grown-in defects and a large BMD cannot be obtained.

On the other hand, using a wafer made of a single crystal having a nitrogen content and a pulling rate falling within the ranges defined by the present invention, the heat treatment conditions in a hydrogen atmosphere were set to the test numbers 19 to 23, which were within the ranges defined by the present invention. In 27-31, 35-39 and 43-47,
It can be seen that no slip occurred, the number of grown-in defects was small, and a BMD having a large BMD density was obtained.

[0050]

[Table 1]

[0051]

As described above, the semiconductor device wafer of the present invention comprises:
There are no void-type defects, that is, grown-in defects, oxygen precipitate defects, and slips in a portion from the surface to a depth exceeding 10 μm, and the density of oxygen precipitates serving as gettering sinks in the bulk portion is sufficiently large. This wafer can improve the quality of devices formed thereon and greatly increase the yield of non-defective products. In addition, the method of the present invention for producing a wafer having such a defect distribution state significantly improves the throughput of the heat treatment step,
The effect contributing to the progress of the wafer manufacturing technology is great.

[Brief description of the drawings]

FIG. 1 Nitrogen addition to silicon single crystal and growth of single crystal
FIG. 3 is a diagram showing a relationship with the diameter of an n-in defect.

FIG. 2 is a diagram showing the effect of adding nitrogen on the relationship between the silicon single crystal pulling rate and the diameter of grown-in defects.

FIG. 3 is a diagram showing the effect of nitrogen addition and pulling rate on the grown-in defect density at the wafer surface.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tatsumi Kusaba 2201 Kamioda, Kokita-cho, Kishima-gun, Saga Prefecture F-term (reference) 4G077 AA02 AB01 CF10 EH09 FE02 FE11 5F053 AA12 AA22 DD01 FF04 GG01 PP03 RR03 RR04

Claims (3)

[Claims] An oxygen precipitate density in a bulk portion inside a wafer is not less than 5 × 10 ⁵ / cm ² , and in a range from a surface serving as an active region to a depth of 10 μm, a grown-in defect of 0.09 μm or more is formed. A silicon wafer having a number of 1.6 × 10 ^-2 pieces / cm ² or less. 2. A nitrogen content of 1 × 10 ^{13 to} 5 × 10 ¹⁵ atoms / cm ^3.
Using a wafer cut from a silicon single crystal grown at a growth rate of 1.2 mm / min or more, the rate of temperature rise when performing a heat treatment of heating in a hydrogen atmosphere is 60 ° C / min or less in a temperature range of 1000 ° C or less. , 10 ° C / min or less in the temperature range exceeding 1000 ° C and 1100 or less, 2 ° C / min in the temperature range exceeding 1100 ° C
2. The method for producing a silicon wafer according to claim 1, wherein the value is not more than min. 3. The method for producing a silicon wafer according to claim 2, wherein when the heating temperature of the heat treatment is T ° C., the temperature is maintained for at least a time satisfying the following expression. Retention time (seconds) ≧ 10 ^-10 × exp {40000 / (T + 273)}