JP3387364B2 - Silicon seed crystal, method for producing the same, and method for producing silicon single crystal using these seed crystals - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a silicon single crystal by the Czochralski method (CZ method), which is so-called seeding (necking).
The present invention relates to a silicon seed crystal used in this method and a method for manufacturing the same in a method for manufacturing a silicon single crystal without performing.

[0002]

2. Description of the Related Art Conventionally, in the production of a silicon single crystal by the Czochralski method, single crystal silicon is used as a seed crystal, which is brought into contact with a silicon melt and then slowly pulled while rotating. Grow sticks. At this time, when the seed crystal is brought into contact with the silicon melt, seed drawing (necking) is performed in order to eliminate dislocations generated at high density in the seed crystal due to thermal shock, and then the crystal is thickened to a desired diameter. Then, the silicon single crystal is pulled up. Such a seed stop is DashNec
It is widely known as the king method and is a common sense when pulling a silicon single crystal ingot by the Czochralski method.

That is, the shape of the seed crystal that has been conventionally used is, for example, as shown in FIGS. 4 (A) and 4 (B), a seed holder having a cylindrical or prismatic shape having a diameter or one side of about 8 to 20 mm. A notch for setting is provided, and the lower tip shape that comes into contact with the silicon melt first is a flat surface. Further, in order to withstand the weight of a heavy single crystal ingot and to pull it up safely, it is difficult to make the seed crystal thinner than the above.

In the seed crystal having such a shape, since the heat capacity of the tip in contact with the melt is large, a sharp temperature difference occurs in the crystal at the moment when the seed crystal comes into contact with the melt, and slip dislocations are densely formed. Cause to. Therefore, the necking is necessary to eliminate the dislocations and grow a single crystal.

In the Dash Necking method, after the seed crystal is brought into contact with the silicon melt, the diameter is once thinned to about 3 mm to form a narrowed portion to eliminate dislocations propagated from slip dislocations introduced into the seed crystal. , To obtain a dislocation-free single crystal.

However, in such a method, even if various necking conditions are selected, it is necessary to narrow down to a minimum diameter of 5 to 6 mm in order to eliminate dislocations. There was not enough strength to suspend and support the weighted single crystal rod, and during the pulling up of the crystal rod, there was a risk of serious accidents such as the breakage of this thin drawn part and the single crystal rod falling. .

Therefore, in pulling up large-diameter, high-weight single crystal rods in recent years, a method using a crystal holding mechanism is being developed (see, for example, Japanese Patent Publication No. 5-65477). Since necking is indispensable for making dislocation-free as described above, this method cannot strengthen the strength of the seed-thinned portion, and instead directly holds the grown crystal rod mechanically. is there.

However, since such a method directly holds a single crystal ingot that slowly grows while rotating at a high temperature, the apparatus becomes complicated and expensive, and heat resistance also arises. . In addition, it is very difficult to actually grasp the grown crystal without giving vibrations, etc., and the grown crystal is polycrystallized, and moreover, it has a complicated mechanism such as rotation and sliding directly on the high temperature silicon melt. Therefore, there is a problem in that the crystal is contaminated with heavy metal impurities.

In order to solve such a problem, the applicant of the present invention has previously disclosed Japanese Patent Application Laid-Open No. 5-139880 and Japanese Patent Application No. 8-871.
Inventions such as No. 87 have been proposed. This invention makes the shape of the tip of the seed crystal wedge-shaped or hollow.
By reducing slip dislocations that enter when the seed crystal comes into contact with the silicon melt as much as possible, dislocation-free is possible even if the diameter of the narrowed portion is made relatively large, thereby improving the strength of the narrowed portion. .

According to this method, since the thickness of the throttle portion can be increased, the strength of the throttle portion can be improved to some extent, but necking is performed to form the throttle portion having slip dislocations. Increasingly large diameter,
The strength may be insufficient for pulling a single crystal ingot having a length of, for example, 150 Kg or more, and a fundamental solution has not been reached yet.

Therefore, as a solution to such a problem, the applicant of the present invention can make a crystal into a single crystal without forming a narrowed portion due to necking, which is the biggest problem in strength, and has a large diameter. A method for producing a silicon single crystal and a silicon seed crystal used therefor capable of pulling a long and heavy silicon single crystal extremely easily without using a complicated device such as a crystal holding mechanism. Succeeded in development, and proposed earlier (Japanese Patent Application No. 9-17
687).

In this method, the shape of the tip which is brought into contact with the silicon melt as a seed crystal is a pointed shape or a shape in which the pointed tip is cut off. First, the tip of the seed crystal is made into a silicon melt. After melting, the seed crystal is melted until the tip of the seed crystal has a desired thickness by lowering the seed crystal at a low speed, and then the seed crystal is slowly lifted to obtain a desired diameter without necking. It is a method for producing a silicon single crystal, such as growing a silicon single crystal ingot.

[0013]

Since the above method does not perform necking, it is possible to fundamentally solve the above-mentioned various problems associated with the formation of the narrowed portion, which is extremely excellent. The results of the running test of
Depending on the shape of the seed crystal and the manufacturing method, dislocations may be easily introduced into the seed crystal at the time of contact and melting of the tip portion of the seed crystal, and it may be difficult to grow a single crystal thereafter, resulting in a low success rate. all right.

Therefore, the present invention has been made in view of the above problems, and the present invention is a method for producing a silicon single crystal by the Czochralski method without performing so-called seeding (necking). The main object of the present invention is to provide a silicon seed crystal and a method for producing the same, which can improve the success rate of the single crystallization in the method for producing a silicon single crystal.

[0015]

In order to solve the above problems SUMMARY OF THE INVENTION, the invention described onset Ming, the silicon seed crystal used in producing the silicon single crystal rod by the Czochralski method, the silicon melt The shape of the tip to be brought into contact is a pointed shape or a shape obtained by cutting off a pointed tip, and the maximum apex angle is 28 degrees or less, which is a silicon seed crystal.

As described above, by making the shape of the tip of the seed crystal into a pointed shape or a shape obtained by cutting off the pointed tip, and setting the maximum apex angle to 28 degrees or less,
When the tip of the seed crystal is first brought into contact with the silicon melt, the contact area with the melt is sufficiently small and the heat capacity of the tip is also sufficiently small, so that a thermal shock or a sharp temperature gradient is formed on the seed crystal. No slip dislocation is introduced.
Further, when the seed crystal is lowered at a low speed and then melted until the tip of the seed crystal has a desired thickness, the contact area between the seed crystal and the melt in the melt gradually increases,
Since the seed crystal can be melted to a desired thickness without forming a sharp temperature gradient in the seed crystal, slip dislocations are not introduced into the seed crystal even at the time of melting. Therefore, the seed crystal can be surely brought into contact with and melted in the melt without causing slip dislocation, and the single crystal ingot can be grown without necking thereafter.

In this case , it is preferable that the maximum apex angle of the seed crystal is 3 degrees or more and 28 degrees or less.

As described above, when the maximum apex angle of the seed crystal is 3 degrees or more, the effect of preventing slip dislocation introduction is sufficient, and the melting time is shortened, the seed crystal is easily manufactured, the strength of the tip portion, etc. From the point of, it is desirable to set the angle range of the maximum apex angle.

[0019] In the invention described in the onset bright and the tip brought into contact with at least a silicon melt of the silicon seed crystal and those etched.

As described above, if the tip portion of the seed crystal that comes into contact with the silicon melt is etched, the surface strain introduced when the seed crystal is mechanically processed and manufactured can be removed. Therefore, when the tip portion of the seed crystal is contacted or melted, slip dislocation is not introduced due to this, and the seed crystal can be contacted and melted more reliably without dislocation.

In this case, in particular , the etching removal amount is 300
It is preferable that the diameter is not less than micron.

If the etching is performed to 300 μm or more, the surface strain can be surely removed, and slip dislocation is not introduced into the seed crystal due to this.

Further, in the invention described in the onset bright and silicon seed crystal using the rounded portion formed by the Czochralski method as pointed tip of the seed crystal.

As described above, if the rounded portion formed by the Czochralski method is used as the tip portion of the seed crystal, mechanical processing or the like is unnecessary, and surface distortion or the like caused by such processing exists. Of course, there is no need to perform the above etching.

Next, the invention is described in the onset bright, the shape of the tip into contact with the silicon melt, pointed shape or pointed tip is shaped to cut the silicon single crystal rod by the Czochralski method In the method for manufacturing a silicon seed crystal used in manufacturing, after mechanically processing the silicon single crystal ingot, which is a raw material of the seed crystal, into the desired seed crystal shape, at least a tip portion to be brought into contact with the silicon melt is etched. This is a method for manufacturing a silicon seed crystal.

As described above, when the seed crystal is manufactured by mechanically processing the silicon single crystal ingot into a desired shape and then etching the seed crystal, a seed crystal having a desired tip shape can be reliably obtained. At the same time, it is possible to manufacture a product having no surface distortion.

Further, the invention described onset Ming, the shape of the tip into contact with the silicon melt, a shape obtained by cutting the pointed shape or pointed tip, the silicon single crystal rod by the Czochralski method In the method for producing a silicon seed crystal used in production, a silicon single crystal ingot, which is a raw material for the seed crystal, is selected by a Czochralski method and has a rounded portion, and the rounded portion has a pointed tip of the seed crystal. It is a method for producing a silicon seed crystal, which is used as a part.

The seed crystal is manufactured by using a silicon single crystal ingot having a rounded portion formed by the Czochralski method, and the rounded portion is used as a sharp tip of the seed crystal. Since the tip does not have to be formed, it is simple, saves material, and does not distort the surface of the finished product.

[0029] Then, the invention described in the onset bright, after contacting a seed crystal to the silicon melt, by raising slowly while rotating it, silicon by the Czochralski method for growing a silicon single crystal rod In the method for producing a single crystal, the seed crystal described above is used as the seed crystal, first the tip of the seed crystal is gently contacted with a silicon melt, and then the seed crystal is lowered at a low speed. Melting until the tip of the seed crystal has a desired thickness, and then slowly raising the seed crystal to grow a silicon single crystal ingot having a desired diameter without performing necking. It is a method for producing crystals.

Further, the invention described onset Ming, after contacting a seed crystal to the silicon melt, by raising slowly while rotating it, silicon by the Czochralski method for growing a silicon single crystal rod In the method for producing a single crystal, the seed crystal produced by the method described above is used as the seed crystal, and first the tip of the seed crystal is gently contacted with a silicon melt, and then the seed crystal is produced at a low speed. By melting it until the tip of the seed crystal has a desired thickness by lowering it, then slowly raising the seed crystal and growing a silicon single crystal ingot having a desired diameter without necking. Is a method for manufacturing a silicon single crystal.

As described above, according to the seed crystal and the method for producing the seed crystal of the present invention, it is possible to reliably obtain a seed crystal having a pointed tip shape in which slip dislocations are not introduced at the time of seed crystal contact and melting. However, if a silicon single crystal is grown by using this without necking, the success rate is significantly improved.

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below, but the present invention is not limited thereto. In order to grow a single crystal without necking in the Czochralski method, when a seed crystal is brought into contact with a silicon melt and then slowly melted to a desired thickness, slip dislocation may not occur in the seed crystal. It is essential. Therefore, the success rate of the method for growing a single crystal without performing necking depends on how the slip dislocation is not generated when the seed crystal comes into contact with the melt and melts.

Therefore, the inventors of the present invention have conducted various experimental studies on the shape and manufacturing method of the seed crystal which does not surely generate slip dislocations when contacting and melting such a silicon melt. The present invention has been found.

The basic shape of the seed crystal used in the method for growing a single crystal ingot without necking is as follows:
The shape of the tip of the seed crystal needs to be a pointed shape or a shape in which a pointed tip is cut off. With such a shape, when the tip of the seed crystal first comes into contact with the silicon melt, the contact area with the melt is small and the heat capacity of the tip is small. This is because no slip dislocation is introduced because no gradient is formed.

Then, when the seed crystal is slowly lowered to melt the tip end portion of the seed crystal to a desired thickness, the contact area between the seed crystal in the melt and the melt gradually increases. The seed crystal can be melted without forming a sharp temperature gradient in the seed crystal, and slip dislocations are not introduced into the seed crystal even during melting.

As a more specific shape of such a seed crystal, the following items have been found in the above proposal. (1) It is preferable that the tip of the seed crystal having a pointed shape or a pointed tip cut off is shaped like a cone or a pyramid. (2) In this case, the length t of the conical portion 7 and the pyramidal portion 8 of the seed crystal shown in FIG. 3 is arbitrary, but is about 1 to 10 times the thickness of the seed crystal, and more preferably 2 to 8 times. What to do. (3) The shape of the pyramid at the tip may be a triangular pyramid, a quadrangular pyramid, or a polygonal pyramid having a larger size. Further, it is not necessary to match the cross-sectional shape of the straight body portion of the seed crystal with the cross-sectional shape of the tip portion, and the tip portion of the prismatic seed crystal may be processed into a cone, and any shape can be combined. Things that can be done. (4) Not only the pointed shape of the seed crystal as shown in FIGS. 3 (A) and 3 (B), but also the pointed shape as shown in FIG. 3 (C) may be cut off. And how to cut the tip is also arbitrary, not limited to cutting horizontally,
For example, as shown in FIG. 3D, it may be cut obliquely.
In this case, the area of the surface contacting the first silicon melt the seed crystal tip, 9π (mm ²⁾ may not more than, more preferably 2.25π (mm ²⁾ or less and it is to that.

A method for producing a single crystal ingot without necking can be carried out depending on the specific shape of the seed crystal. Therefore, basically, in the present invention, the above conditions are conditions that are directly applied. However, there are variations in the success rate only under such conditions,
In order to more surely contact and melt the seed crystal in the silicon melt without dislocation, it is necessary to further devise and specify the seed crystal shape.

Therefore, the present inventors have investigated in detail the sharpness of the tip of the seed crystal and the success rate of the method for growing a single crystal ingot without necking. This is an examination of the maximum apex angle of the tip of the seed crystal and the dislocation-free rate of the single crystal rod.

Then, the maximum apex angle of the tip of the seed crystal is 28
It turns out that the success rate drops sharply when the frequency is exceeded. Although the details of the reason are unknown, when the maximum apex angle exceeds 28 degrees, the slip dislocation occurs due to thermal shock when the silicon melt comes into contact, because the heat capacity of the tip portion is not sufficiently small. However, it is considered that a steep temperature gradient is formed during the subsequent melting due to the large increase rate of the contact area, and slip dislocation may occur even if the melting speed is reduced. Therefore, in the seed crystal according to the present invention, it is desirable that the maximum apex angle of the tip be 28 degrees or less in order to increase the success rate.

In this case, the maximum apex angle referred to in the present invention is the apex angle of the tip portion to be melted in the silicon melt, as shown in FIG. To tell. Therefore, in the case where the tip has a conical shape as shown in FIG. 1A, the apex angle = maximum apex angle = constant,
In the case where the tip portion has a shape like a pyramid as shown in FIG. 1B, it indicates the apex angle on the diagonal cross section side.

Also in the present invention, the shape of the tip is not limited to the pointed tip of the seed crystal as shown in FIGS. As described above, a shape with a sharp tip cut off may be used. The method of cutting the tip is also arbitrary, and the cutting is not limited to horizontal cutting, and may be cut diagonally as shown in FIG. 1D, for example. In this case, the meaning of the maximum apex angle in the present invention is indicated by the maximum apex angle α before cutting, regardless of the presence or absence of such cutting.

On the other hand, the maximum apex angle α is better as it is smaller from the viewpoint that slip dislocations are not introduced into the seed crystal, but from a practical viewpoint, it is preferably 3 degrees or more. .

This is because the effect of preventing slip dislocation introduction is sufficient if the maximum apex angle of the seed crystal is sharpened to 3 degrees, and it is difficult to sharpen the tip too much in processing a brittle and hard silicon single crystal. In addition, handling problems such as damage will occur. In addition, the sharper the tip, the longer the length t of the tip to be melted, the longer the melting time of the tip, and the more wasteful the production of the single crystal ingot. Because.

Next, in the method for producing a seed crystal of the present invention having such a shape, a silicon single crystal ingot, which is a material for the seed crystal, is mechanically processed and brought into contact with a desired shape, that is, a silicon melt. The shape of the tip to be made is a pointed shape or a shape obtained by cutting off a pointed tip, and the maximum apex angle may be 28 degrees or less.

However, as described above, when the seed crystal is manufactured by mechanically processing the silicon single crystal ingot into a desired shape, processing distortion occurs on the surface thereof. Unless such a processing strain is completely removed, even if the tip of the seed crystal has the desired shape described above, the seed crystal will slip from the processing strain when it comes into contact with the silicon melt and melts. Dislocations occur and the dislocation free rate is reduced.

In this respect, since the conventional Czochralski method for necking is a method in which slip dislocations are originally generated in the narrowed portion, the generation of slip dislocations due to this processing strain is not so important. In the present invention, it is necessary to completely suppress the occurrence of slip dislocations in the seed crystal, so removal of this processing strain is important.

Then, in order to remove the surface processing strain, after mechanically processing into a desired shape, at least the tip end portion which is brought into contact with the silicon melt may be etched. By etching, the processing strain on the surface can be removed easily and reliably.

In this case, the surface strain is not generated only by mechanical processing, but by etching,
Since the entire surface is removed by etching, even if strains other than the above-mentioned strains exist, they can be removed together.

The etching may be carried out by immersing the whole seed crystal in the etching solution, but at least the tip portion which comes into contact with and melts the silicon melt must be etched. The etching solution is not particularly limited as long as it can etch silicon, but mixed acid such as hydrofluoric acid + nitric acid can be used.

In this case, the etching removal amount is 3
It is preferably at least 00 microns. The processing strain due to mechanical processing is deep and is generally about 200 to 300 on the surface.
This is because it reaches the micron depth. Therefore,
If the etching is performed for 300 μm or more, the surface strain can be surely removed, and slip dislocation is not introduced into the seed crystal due to this.

The seed crystal produced in this manner has a tip shape having a desired sharpness and has no distortion on its surface. Therefore, when the tip end of the seed crystal is contacted or melted, slip dislocation is caused. Is less likely to be introduced, and the seed crystal can be contacted and melted more reliably without dislocation.

As another method for producing a seed crystal according to the present invention, a rounded portion grown by a usual Czochralski method is used instead of forming a desired tip shape by mechanical processing. Is also good. This is to select a silicon single crystal ingot, which is a material of a seed crystal, having a rounded portion formed by the Czochralski method, and use the rounded portion as a pointed tip portion of the seed crystal.

For example, as shown in FIG. 2, after the seed crystal 1 is brought into contact with the melt by the ordinary Czochralski method, necking is performed to form the narrowed portion 3 to make it dislocation-free, and thereafter the diameter is increased. , A desired diameter (seed crystal diameter) is grown for a while, and then a rounded portion 6 is formed to finish the growth of the single crystal. The rounded part of the small crystal thus formed is used as the tip of the seed crystal, and on the opposite side of the rounded part, if the cutout for setting the seed crystal in the seed holder is processed, the desired tip of the present invention can be obtained. A seed crystal having a partial shape can be manufactured.

As described above, if the rounded portion 6 produced by the Czochralski method is used as the pointed tip of the seed crystal, it is not necessary to form the tip by machining, so that it is simple. It also saves material,
Since there is no strain on the surface of the resulting seed crystal, there is an advantage that it is not necessary to carry out etching as described above.

In this case, the formation of the rounded portion by the Czochralski method does not need to be performed only for producing the seed crystal as described above, and as shown by the dotted line in FIG.
It goes without saying that it may be manufactured by using the rounded portion of a silicon single crystal rod for a semiconductor wafer which is normally manufactured. The rounded portion of a normal single crystal silicon rod is discarded because it does not reach the desired diameter, and in that sense, it also saves material and can be manufactured at an extremely low cost.

Then, using the seed crystal of the present invention having the above-mentioned characteristics or the seed crystal produced by the method of the present invention, first the tip of the seed crystal is gently contacted with the silicon melt, and then the seed crystal is slowly moved. The tip of the seed crystal is melted by lowering until the desired thickness, and then the seed crystal is slowly raised to grow a silicon single crystal ingot having a desired diameter without necking. For example, since slip dislocations are not surely introduced at the time of contact with the seed crystal and at the time of melting, the success rate of growing the silicon single crystal without necking is significantly improved.

[0057]

EXAMPLES Next, examples and comparative examples of the present invention will be shown, but the present invention is not limited to these. (Examples, Comparative Examples) The success rate of dislocation-free when a single crystal was grown without necking was investigated by changing the maximum apex angle of the tip of the seed crystal. As a seed crystal, the orientation <
100> 10 mm square, the tip of which was mechanically processed into a cone having various apex angles, and the whole seed crystal was etched in an etching solution of hydrofluoric acid + nitric acid was used.

Using these seed crystals, first, the seed crystals were held directly above the silicon melt for 20 minutes and sufficiently preheated.
Then, the tip of the seed crystal is gently brought into contact with the silicon melt by descending at a speed of 2 mm / min, and then descended at the same speed in the melt until the diameter of the tip of the seed crystal is about 6 mm. It melted until. from here,
The seed crystal was slowly started to rise, and without straightening, the crystal was immediately thickened to a diameter of about 100 mm, and then the straight barrel portion was grown to about 10 cm. Finally, a rounded portion was formed to complete the growth of the silicon single crystal ingot.

The ratio of the number of grown single crystal rods to the number of grown single crystal rods indicating whether or not the single crystal rods formed are dislocation-free single crystals,
The success rate was calculated. Results are shown in FIG.

As is clear from the above results, the success rate is high when the maximum apex angle of the seed crystal is 28 degrees or less, but the success rate sharply decreases when it exceeds 28 degrees.

The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, has substantially the same configuration as the technical idea described in the scope of the claims of the present invention, and has any similar effect to the present invention. It is included in the technical scope of the invention.

For example, the present invention is not limited to the ordinary Czochralski method, but the MCZ method (Magnetic field applied Czochralski method) in which a magnetic field is applied when pulling a silicon single crystal.
Needless to say, the term “Czochralski method” used in the present specification includes not only the ordinary Czochralski method but also the MCZ method.

[0063]

According to the seed crystal and the method for producing the seed crystal of the present invention, the success rate of the method for growing a silicon single crystal ingot by the Czochralski method without necking can be significantly improved. A seed crystal that can be obtained can be obtained. As a result, a large-diameter, long and heavy silicon single crystal can be pulled very easily.

[Brief description of drawings]

FIG. 1 is a perspective view of a seed crystal according to the present invention. (A) A cylindrical tip having a conical shape,
(B) A quadrangular prism-shaped tip having a quadrangular pyramid shape,
(C) Horizontally cut tip, (D) Diagonally cut tip.

FIG. 2 is an explanatory diagram of a case where a seed crystal is manufactured using a rounded portion. (A) When manufacturing an ingot having a rounded portion by a normal Czochralski method, (B) When using the rounded portion of a single crystal ingot for a semiconductor wafer.

FIG. 3 is a perspective view of a seed crystal according to the previously proposed invention. (A) A cylindrical tip having a conical shape,
(B) A quadrangular prism-shaped tip having a quadrangular pyramid shape,
(C) Horizontally cut tip, (D) Diagonally cut tip.

FIG. 4 is a perspective view of a conventional seed crystal. (A) Cylindrical shape, (B) Square pillar shape.

FIG. 5 is a result chart showing the results of Examples and Comparative Examples.

[Explanation of Codes] 1 ... Seed crystal, 2 ... Slip dislocation, 3 ... Drawing part, 5 ... Straight body part,
6 ... Rounding part, 7 ... Cone part,
8 ... Pyramidal part. t ... Tip length,
α ... Maximum apex angle.

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) C30B 15/36 C30B 29/06 502 H01L 21/208

Claims (4)

(57) [Claims] 1. In a silicon seed crystal used for manufacturing a silicon single crystal ingot by the Czochralski method, the shape of the tip portion to be brought into contact with the silicon melt is a pointed shape or a shape in which a pointed tip is cut off. , Its maximum apex angle is 2
8 degrees Ri der hereinafter is in contact with at least the silicon melt
The amount of etching removal of the tip part to be made is 300 microns or more
A silicon seed crystal, which is characterized by being etched . 2. A silicon seed crystal used when producing a silicon single crystal ingot by the Czochralski method, wherein the shape of the tip to be brought into contact with the silicon melt is a pointed shape or a shape in which the pointed tip is cut off. In the manufacturing method, after a silicon single crystal ingot, which is a seed crystal material, is mechanically processed into the desired seed crystal shape, at least a tip portion which is brought into contact with the silicon melt is etched and removed at a rate of 300
A method for producing a silicon seed crystal, which comprises etching as a micron or more . 3. After bringing the seed crystal into contact with the silicon melt,
In the method for producing a silicon single crystal by the Czochralski method, in which a silicon single crystal ingot is grown by slowly pulling it while rotating, the seed crystal according to claim 1 is used as the seed crystal, and After the tip of the crystal is gently contacted with the silicon melt, the seed crystal is lowered at a low speed to melt until the tip of the seed crystal has a desired thickness, and then the seed crystal is slowly raised. Then, a silicon single crystal ingot having a desired diameter is grown without performing necking. 4. After bringing the seed crystal into contact with the silicon melt,
In the method of producing a silicon single crystal by the Czochralski method, in which a silicon single crystal ingot is grown by slowly pulling it while rotating, the seed crystal produced by the method according to claim 2 is used as the seed crystal. First, the tip of the seed crystal is gently contacted with a silicon melt, and then the seed crystal is lowered at a low speed to melt until the tip of the seed crystal has a desired thickness. Is slowly raised, and a silicon single crystal ingot having a desired diameter is grown without performing necking, and a method for producing a silicon single crystal.