JP2014116450A - Cylindrical grinder and manufacturing method of single-crystal wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cylindrical grinder and a manufacturing method of a single-crystal wafer, with which high-quality single-crystal wafers with variations in a radius in a circumferential direction suppressed can be efficiently obtained after a cylindrical grinding step, a slicing step and an etching step.SOLUTION: A manufacturing method of a single-crystal wafer includes the steps of; cylindrically grinding an outer circumferential part of a single-crystal ingot; slicing the ground ingot into a wafer shape; and etching the outer circumferential part of the single-crystal wafer. In the method, the single-crystal wafer is manufactured by executing the cylindrical grinding step, the slicing step and the etching step while changing a radius of the ingot by periodically changing and controlling a grindstone feeding amount in a vertical direction to an ingot axis of a grindstone in accordance with a position of the ingot in the circumferential direction so as to cancel a periodical radius change amount caused by etching on the basis of the periodical radius change amount corresponding to the position of the wafer in the circumferential direction in the etching step.

Description

  The present invention relates to a cylindrical grinding machine for cylindrically grinding an outer peripheral portion of a single crystal ingot and a method for manufacturing a single crystal wafer.

For single crystal wafers (hereinafter sometimes simply referred to as wafers), for example, silicon single crystal wafers (hereinafter sometimes simply referred to as silicon wafers) used as LSI (Large Scale Integration Circuit) substrate materials, etc. Therefore, surface cleanliness and flatness are required.
The reason why silicon wafers are required to be flat is to improve process accuracy such as in-plane uniformity in LSI manufacturing process processes typified by lithography and CVD.

  In addition to the aforementioned items, the roundness of the wafer can be given as an example of the quality item of the wafer for improving the accuracy of the LSI manufacturing process.

  Here, the roundness is a value defined by “represented by the difference between the radii of two circles when the circular shape is sandwiched between two concentric geometric circles and the interval between the concentric circles is minimum”. Yes (see Non-Patent Document 1).

Japanese Patent No. 4862896

JIS B 0621-1984

The present inventor has intensively studied the roundness of the wafer.
FIG. 7 shows the shape of the outer peripheral portion of the silicon wafer (plane orientation (100)) (see the prior art in the dotted line). The shape measurement was performed using a Talylond manufactured by Taylor Hobson. The roundness was 5.3 μm.
In the measurement, the position of ± 10 degrees around the notch portion of the wafer (below the measurement diagram of FIG. 7) is excluded.
FIG. 7 also shows the reference circle. This reference circle is a LS (Least Squares Circle) circle, and is a circle that minimizes the sum of the distances from the center of the circle to the shape of the outer periphery.

  As shown in FIG. 7, the shape of the silicon wafer is not a perfect circle, but has a shape in which irregularities are repeated at a cycle of 45 °. That is, there is a variation in radius in the circumferential direction. Due to this uneven shape, the roundness value of the silicon wafer deteriorates, and for example, the roundness requested by the customer may not be satisfied.

The inventor further investigated the cause of the unevenness and found that the cause of the uneven shape was etching during the wafer fabrication process.
For example, a single crystal ingot pulled up by the CZ method or the like is cylindrically ground at the outer peripheral portion and sliced into a wafer shape. The roundness at this point is high. However, after that, various processes including etching are performed on the slice wafer. In the etching process in such a wafer manufacturing process, the uneven shape on the outer periphery of the wafer is formed due to the difference in the etching rate depending on the crystal orientation.

As a method for eliminating the unevenness, there are a chamfering apparatus and a chamfering method that change the chamfering shape in a cycle of 45 ° in the circumferential direction when chamfering the wafer (see Patent Document 1).
However, this method is processing for each wafer, and in order to maintain productivity, a plurality of chamfering devices must be prepared, which is inefficient.

  The present invention has been made in view of the above-mentioned problems, and is capable of efficiently producing a high-quality single crystal wafer in which variation in the radius in the circumferential direction is suppressed after undergoing a cylindrical grinding process, a slicing process, and an etching process. An object of the present invention is to provide a cylindrical grinding machine and a method for producing a single crystal wafer.

  In order to achieve the above object, the present invention includes a step of cylindrically grinding an outer peripheral portion of a single crystal ingot using a grinding wheel, a step of slicing the single crystal ingot into a wafer after the cylindrical grinding step, and the slice A method of manufacturing a single crystal wafer comprising a step of etching at least an outer peripheral portion of a single crystal wafer after the step, wherein a periodic radius change due to etching according to a circumferential position of the single crystal wafer in the etching step Based on the amount, the grinding wheel feed amount in the direction perpendicular to the single crystal ingot axis of the grinding wheel is periodically changed according to the circumferential position of the single crystal ingot so as to cancel out the periodic radius change amount. And performing the cylindrical grinding process while changing the radius of the single crystal ingot by changing to the slicing process and the etching process It was carried out, to provide a method for producing a single crystal wafer, characterized in that to produce a single crystal wafer.

In this way, first, it is possible to obtain a single crystal ingot whose radius is changed according to the position in the circumferential direction. Moreover, since it is a single crystal ingot that has been ground so as to cancel the amount of periodic radius change due to etching according to the circumferential position of the single crystal wafer in the etching process, after passing through the slicing process and the etching process On the contrary, it is possible to obtain an etched wafer in which variation in the radius in the circumferential direction is extremely suppressed.
Moreover, in the cylindrical grinding process, the radius in the circumferential direction can be easily changed at a time for each single crystal ingot, that is, for all the single crystal wafers, and the efficiency is high.

  At this time, the crystal orientation of the single crystal ingot can be set to <100> or <111>, and the change period of the grindstone feed amount can be set to 45 ° or 120 °, respectively.

  In this way, an etched wafer having a plane orientation (100) or (111) in which variation in the radius in the circumferential direction is suppressed can be obtained.

  Further, a periodic radius change amount by etching according to the circumferential position of the single crystal wafer can be obtained by performing a test in advance.

  By doing this, it is possible to accurately determine the amount of periodic radius change by etching according to the circumferential position of the wafer using the same process, and as a result, the variation in the radius in the circumferential direction is further increased. A suppressed etched wafer can be obtained.

  In addition, the etching step can be performed using any one or more of an aqueous sodium hydroxide solution and an aqueous potassium hydroxide solution.

  By doing so, it is possible to perform etching while relatively suppressing the shape change of the main surface of the single crystal wafer due to the etching process, and it is possible to obtain an etched wafer with high flatness.

  Further, the roundness of the single crystal wafer after the etching step can be set to 3.0 μm or less.

  According to the present invention, it is possible to obtain a higher quality etched wafer in which variation in the radius in the circumferential direction is sufficiently suppressed.

  The present invention is also a cylindrical grinding machine for cylindrically grinding the outer periphery of a single crystal ingot using a grinding wheel, a holder for holding and rotating the single crystal ingot, and a single crystal held by the holder A grinding wheel for grinding the outer periphery of the ingot, and a grinding wheel feed amount in a direction perpendicular to the single crystal ingot axis of the grinding wheel are controlled by numerical control, and the radius of the single crystal ingot is controlled according to the position in the circumferential direction. And a control device for feeding the grinding wheel in a direction perpendicular to the single crystal ingot axis of the grinding wheel when grinding according to a circumferential position of the single crystal ingot held by the holder. Provided is a cylindrical grinding machine characterized in that the amount is periodically changed and controlled.

Unlike the conventional cylindrical grinding machine, which uniformly grinds the outer periphery of the single crystal ingot, the present invention is different from the above in the present invention in that the radius is periodically changed according to the circumferential position of the single crystal ingot. It is possible to grind while changing. Therefore, it is possible to obtain a single crystal ingot whose radius is changed according to the position in the circumferential direction, and after etching after slicing into a wafer shape, the variation in the radius in the circumferential direction is extremely suppressed. It becomes possible to obtain a wafer.
Moreover, with the cylindrical grinding machine of the present invention, the radius in the circumferential direction can be easily changed at a time for each single crystal ingot, that is, for all the single crystal wafers, and the efficiency is high.

  At this time, the crystal orientation of the single crystal ingot may be <100> or <111>, and the change period of the grindstone feed amount may be 45 ° or 120 °, respectively.

  With such a configuration, an etched wafer having a plane orientation (100) or (111) in which variation in the radius in the circumferential direction is suppressed can be obtained.

  Even if a single crystal ingot is uniformly cylindrically ground using a conventional cylindrical grinder, if the slice is subjected to an etching process, the radius of the crystal depends on the circumferential position due to the crystal orientation anisotropy of etching. Although the size becomes non-uniform, according to the present invention, a high-quality single crystal wafer in which variation in the radius in the circumferential direction is suppressed can be efficiently obtained after the etching process.

It is the schematic which shows an example of the cylindrical grinding machine of this invention. It is explanatory drawing which shows an example of the relationship between the outer peripheral surface of an ingot, and the advancing direction of a grinding wheel. It is a graph which shows an example of the numerical control of the vertical grindstone feed amount in this invention. It is explanatory drawing which shows an example of the process of the manufacturing method of the single crystal wafer of this invention. It is a measurement figure which shows an example of the shape of the outer peripheral part of the silicon wafer by the manufacturing method of this invention. It is a graph which shows an example of the difference of the radius of the silicon wafer by this invention and the conventional method, and the radius of a reference | standard circle according to the position of the circumferential direction. It is a measurement figure which shows an example of the shape of the outer peripheral part of the silicon wafer by the manufacturing method of the conventional wafer.

Hereinafter, the present invention will be described in detail as an example of an embodiment with reference to the drawings, but the present invention is not limited thereto.
FIG. 1 shows an example of a cylindrical grinding machine of the present invention. The cylindrical grinding machine 1 of the present invention first includes a holder 3 that holds and rotates a single crystal ingot 2 and a grinding wheel 4 that grinds the outer peripheral portion of the ingot 2.

  Here, a silicon single crystal ingot (hereinafter sometimes simply referred to as a silicon ingot) will be described as an example of the single crystal ingot (hereinafter also simply referred to as an ingot) 2, but of course the present invention is limited to this. It is not something. The crystal orientation of the ingot 2 is not particularly limited and can be determined as appropriate. Here, a case where the crystal orientation of the ingot 2 is <100> is taken as an example, but it may be, for example, <111>.

  The holder 3 includes a clamp 5 that holds the ingot 2 and a rotating means 6. The ingot 2 held by the clamp 5 by the rotating means 6 can be rotated around the axis. For example, the holder 3 can be the same as the conventional one. For example, the rotating means 6 can be the same as the conventional one.

And the grinding wheel 4 itself is not specifically limited, What is necessary is just what can cylindrically grind the outer peripheral part of the ingot 2, For example, the same thing as the past can be used.
The grinding wheel 4 is further provided with means for rotating and moving at high speed (grinding wheel moving means 7). The grinding wheel moving means 7 can move the grinding wheel 4 along the axial direction of the ingot 2 and also along the rotation axis direction of the grinding wheel 4 (that is, the direction perpendicular to the axis of the ingot 2). Can be moved.

  The cylindrical grinding machine 1 further includes a control device 8 for controlling the rotation of the ingot 2 and the rotation and movement of the grinding wheel 4. The control device 8 can be a computer, for example. By setting a program in the computer in advance, conditions such as the rotation speed of the ingot 2 are adjusted, and the rotation speed, movement speed, and movement amount of the grinding wheel 4 according to the rotation conditions of the ingot 2 (whetstone feed amount. The amount of movement in the direction perpendicular to the axis of the ingot 2 is defined as the vertical grinding wheel feed amount).

  At the time of grinding, since the grinding wheel 4 is set to move while rotating in the axial direction of the ingot 2 while the ingot 2 is rotating, grinding is performed by drawing a spiral on the outer periphery of the ingot. It will be. FIG. 2 shows the relationship between the outer peripheral surface of the ingot 2 (crystal orientation <100>) and the traveling direction of the grinding wheel 4. An arrow indicates the traveling direction of the grinding wheel 4.

In particular, during grinding, the grinding wheel feed amount along the direction perpendicular to the axis of the ingot 2 is changed in synchronization with the rotation of the ingot 2. More specifically, the vertical grindstone feed amount of the grinding wheel 4 is periodically changed and controlled in accordance with the circumferential position of the ingot 2.
Since the ingot 2 is rotated during grinding, if the vertical grinding wheel feed amount of the grinding stone 4 is set to be periodically changed and controlled as described above, the outer circumference of the ingot 2 is set according to the circumferential position. The grinding amount of the part changes periodically. That is, the radius of the ground ingot is periodically changed according to the position in the circumferential direction. In conventional cylindrical grinding, grinding was performed so as to improve the roundness of the ingot after grinding as much as possible. However, as described above, the cylindrical grinding machine 1 of the present invention dares to vary the radius in the circumferential direction. In addition, an ingot having irregularities on the outer peripheral portion can be obtained.

In addition, as a change period of the vertical grindstone feed amount, for example, when the crystal orientation of the ingot 2 to be cylindrically ground is <100>, it can be set to be 45 °.
Here, FIG. 3 shows an example of numerical control of the vertical grindstone feed amount with respect to the ingot 2 (crystal orientation <100>). In FIG. 3, the vertical axis shows the amount of feed of the vertical grindstone, and the horizontal axis shows the angle in the circumferential direction from the crystal orientation <110> in the cross section of the ingot 2. The change cycle is 45 °, and the vertical grindstone feed amount is periodically changed and controlled between 0 and 5.0 μm. The grinding stone 4 is moved by 5.0 μm toward the ingot 2 along the direction perpendicular to the axis of the ingot 2 at intervals of 0 ° to 45 °. On the other hand, the grinding wheel 4 is pulled back in the direction opposite to the ingot 2 along the direction perpendicular to the axis of the ingot 2 at intervals of 22.5 ° to 45 °, and the vertical grinding wheel feed amount is set to 0 μm.
Further, referring to FIG. 2, when the grinding wheel 4 grinds the ingot along the arrow, the vertical grinding wheel feed amount is increased when grinding the region on the dotted line at 45 ° intervals (a 5.0 μm vertical grinding wheel). (Feed amount).

Further, when the crystal orientation is <111>, the change cycle of the vertical grindstone feed amount can be set to 120 °.
Of course, the change period is not limited to these, and can be appropriately determined according to the crystal orientation of the ingot 2 or the like.

Next, the manufacturing method of the single crystal wafer of the present invention using the cylindrical grinding machine 1 will be described. Here, a silicon single crystal wafer will be described as an example, but the present invention is not limited to this.
For example, a silicon wafer is manufactured along the process shown in FIG. 4 having a preliminary test. The manufacturing method of the present invention is not limited to this, and a preliminary test is not necessarily performed. For example, a silicon wafer can be manufactured using past accumulated data.

(Preliminary test)
First, a sample wafer for a preliminary test is prepared. For example, the outer peripheral portion of a silicon single crystal ingot grown by the CZ method is cylindrically ground (cylindrical grinding step: FIG. 4A). The cylindrical grinder used in this step is not particularly limited, and the same conventional one can be used. By the conventional cylindrical grinding method, the outer periphery of the ingot is uniformly cylindrically ground to obtain an ingot having no irregularities on the outer periphery.

Next, a silicon wafer is obtained by slicing into a wafer shape (slicing step: FIG. 4B). Further, it is subjected to a lapping process or a double-sided grinding process as required (FIG. 4C).
Further, at least the outer peripheral portion of the silicon wafer is etched (etching process: FIG. 4D).
As the etching treatment, for example, one or more of a sodium hydroxide aqueous solution and a potassium hydroxide aqueous solution may be used. However, the present invention is not limited to these, and an appropriate one can be selected each time. Then, for example, an etching treatment for 10 minutes can be performed using a 50 mass% sodium hydroxide aqueous solution at a temperature of 83 ° C.
Such alkaline etching is preferable because the shape maintaining performance of the front and back surfaces of the wafer is relatively higher than that of acid etching, and it is easy to achieve flatness requirements from customers.

  At this time, due to the crystal orientation anisotropy of the alkali etching, the etching amount varies periodically depending on the position of the silicon wafer in the circumferential direction, and the shape of the outer peripheral portion becomes non-uniform. That is, the radius varies depending on the position in the circumferential direction, and the etched wafer has irregularities on the outer periphery.

  After the etching, the shape of the outer peripheral portion of the etched wafer is measured to obtain periodic radius variation, roundness, etc. according to the position in the circumferential direction.

On the other hand, before etching, the radius is substantially uniform in the circumferential direction by the previously performed cylindrical grinding.
From the values of the radii before and after the etching, it is possible to obtain a periodic radius change amount by the etching according to the position in the circumferential direction.

  For example, after etching, the shape of the outer peripheral portion of the silicon wafer similar to that shown in FIG. 7 can be obtained. Convex portions are seen at intervals of 0 ° to 45 ° in the circumferential direction from the crystal orientation <110>, and concave portions are seen at intervals of 22.5 ° to 45 °. Before the etching, since the size of the radius is substantially uniform in the circumferential direction, the convex portion of FIG. 7 has a small etching amount in the etching process (that is, the radius is not relatively changed before and after the etching). It can be seen that the recess had a large amount of etching (the radius changed greatly (becomes smaller)).

(Setting cylindrical grinding conditions)
Based on the radius variation obtained in this way, the conditions in the cylindrical grinding step in this test are set (FIG. 4E).
More specifically, the vertical grinding wheel feed amount is changed and controlled periodically and non-uniformly according to the position in the circumferential direction in the cylindrical grinding process in advance so as to cancel out the periodic radius change amount due to etching. The condition is set so that the radius changes with the outer periphery of the surface being uneven.
In other words, the amount of cylindrical grinding is reduced in advance in a portion that is etched a lot in the etching process (the feed amount of the vertical grindstone is reduced), and the amount of cylindrical grinding is relatively increased in a portion that is etched a little. (Set the vertical grinding wheel feed amount large).

For example, if a silicon wafer (surface orientation (100)) having an outer peripheral shape as shown in FIG. 7 is obtained after etching, the feed amount of the vertical grindstone is set to a numerical value as shown in FIG. 3 so as to be more uniform after etching. Control. That is, regarding the cylindrical grinding condition of the ingot with the crystal orientation <100>, the vertical grindstone feed amount is increased at intervals of 0 ° to 45 ° in the circumferential direction from the crystal orientation <110> (locations where the etching amount is small) ( 5.0 μm). On the other hand, the vertical grindstone feed amount is decreased (0 μm) at intervals of 22.5 ° to 45 ° (locations where the etching amount is large).
Thus, by setting the cylindrical grinding condition in which the change period of the vertical grinding wheel feed amount is 45 °, it is expected that the variation in the radius in the circumferential direction is finally suppressed after the etching.

  In addition, even when the crystal orientation of the ingot is <111>, a cylinder whose vertical grinding wheel feed amount change period is 120 ° so as to cancel out the periodic radius change amount by etching according to the position in the circumferential direction. Grinding conditions can be set.

(main exam)
After setting the cylindrical grinding conditions in this way, the test is performed. First, a silicon single crystal ingot was grown by the CZ method in the same manner as in the preliminary test, and based on the cylindrical grinding conditions obtained as described above, instead of cylindrical grinding with a uniform grinding amount in the circumferential direction, The control device 8 of the cylindrical grinding machine 1 synchronizes with the rotation of the ingot 2 and periodically changes and controls the feed amount of the vertical grinding wheel while moving the grinding wheel 4 in the axial direction of the ingot 2. Grind. As a result, an ingot whose radius changes periodically according to the position in the circumferential direction is obtained (FIG. 4F).

Such an ingot with a non-uniform radius in the circumferential direction is sliced into a wafer shape (FIG. 4G), and after lapping or double-sided grinding (FIG. 4H) as necessary, a preliminary test and Etching is performed under the same conditions (FIG. 4I). At this time, as in the preliminary test, the etching amount varies depending on the position in the circumferential direction (that is, the crystal orientation) due to the crystal orientation anisotropy of the etching.
However, in the manufacturing method of the present invention, the etching anisotropy depending on the crystal orientation in the etching process is considered in the first place, and the non-uniform etching corresponding to the position in the circumferential direction caused thereby is canceled out. In the cylindrical grinding step (FIG. 4F), cylindrical grinding is performed in advance so that the outer peripheral portion is intentionally uneven (the radius is nonuniform). As a result, after the etching process, variation in the radius of the etched wafer in the circumferential direction is extremely suppressed as compared with the conventional product, and a high-quality wafer with high roundness can be obtained.

  Moreover, as described above, the outer peripheral shape corresponding to the crystal orientation anisotropy of the etching is already formed in the cylindrical grinding process of the ingot. That is, instead of creating a corresponding outer peripheral shape one by one for each sliced wafer, ingots, that is, the outer peripheral shapes for all the wafers can be formed at once in a cylindrical grinding process, so it is convenient Besides being efficient. Without lowering productivity, it is not necessary to prepare multiple devices for creating an outer peripheral shape corresponding to the crystal orientation anisotropy of etching for each wafer. A quality etched wafer can be produced.

In FIG. 5, an example of the shape of the outer peripheral part of the silicon wafer (plane orientation (100)) by the manufacturing method of this invention is shown. The measurement was performed using a Talylond manufactured by Taylor Hobson. For comparison, FIG. 5 also shows the shape of the outer peripheral portion of the silicon wafer according to the conventional method shown in FIG.
Further, FIG. 6 is a graph showing the difference between the radius of the silicon wafer according to the present invention and the conventional method and the radius of the reference circle according to the position in the circumferential direction.

  As shown in FIG. 5 and as described above, in the prior art, the periodic unevenness in the outer peripheral portion is severely seen, and the variation in radius is large. As shown in FIG. 6, the difference in radius from the reference circle is in the range of −3 to 2.5 μm. The roundness was 5.3 μm.

  On the other hand, in the case of the silicon wafer according to the present invention, as shown in FIG. As can be seen from FIG. 6, the difference in radius from the reference circle is in the range of −1.2 to 1.6 μm, and the difference from the reference circle is smaller than that in the prior art. It can be seen that the roundness is 2.8 μm, which is an improvement over the prior art. An etched wafer having such a roundness of 3.0 μm or less has extremely high quality and can sufficiently satisfy customer requirements.

  Note that the subsequent mirror polishing step shown in FIG. 4 (FIG. 4 (J)) and the like are not particularly limited, and can be performed, for example, by a method similar to the conventional method.

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

DESCRIPTION OF SYMBOLS 1 ... Cylindrical grinding machine, 2 ... Single crystal ingot, 3 ... Holder, 4 ... Grinding wheel,
DESCRIPTION OF SYMBOLS 5 ... Clamp, 6 ... Rotating means, 7 ... Grinding wheel moving means, 8 ... Control apparatus.

Claims (7)

A step of cylindrical grinding the outer periphery of the single crystal ingot using a grinding wheel, a step of slicing the single crystal ingot into a wafer after the cylindrical grinding step, and etching at least the outer periphery of the single crystal wafer after the slicing step A method for producing a single crystal wafer having a processing step,
Based on the periodic radius variation due to etching according to the circumferential position of the single crystal wafer in the etching step, the circumferential radius variation of the single crystal ingot is offset so as to cancel the periodic radius variation. The slicing step is performed after the cylindrical grinding step while changing the radius of the single crystal ingot by periodically changing the grinding wheel feed amount in the direction perpendicular to the single crystal ingot axis of the grinding wheel according to the position. And a method of manufacturing a single crystal wafer, wherein an etching process is performed to manufacture a single crystal wafer.   The crystal orientation of the single crystal ingot is set to <100> or <111>, and the change cycle of the grindstone feed amount is set to 45 ° or 120 °, respectively. Method.   3. The method for producing a single crystal wafer according to claim 1, wherein a periodic radius change amount by etching according to a position in a circumferential direction of the single crystal wafer is obtained by performing a test in advance.   The single-crystal wafer manufacturing method according to any one of claims 1 to 3, wherein the etching step is performed using any one or more of a sodium hydroxide aqueous solution and a potassium hydroxide aqueous solution. Method.   5. The method for manufacturing a single crystal wafer according to claim 1, wherein the roundness of the single crystal wafer after the etching step is set to 3.0 μm or less. A cylindrical grinding machine that cylindrically grinds the outer periphery of a single crystal ingot using a grinding wheel,
A holder for holding and rotating the single crystal ingot, a grinding wheel for grinding an outer peripheral portion of the single crystal ingot held by the holder, and a grinding wheel feed amount in a direction perpendicular to the single crystal ingot axis of the grinding wheel Control by numerical control, comprising a control device for controlling the radius of the single crystal ingot according to the circumferential position,
The control device periodically changes and controls a grinding wheel feed amount in a direction perpendicular to the single crystal ingot axis of the grinding wheel when grinding according to a circumferential position of the single crystal ingot held by the holder. A cylindrical grinding machine characterized by being a thing.   The cylindrical grinding machine according to claim 6, wherein a crystal orientation of the single crystal ingot is <100> or <111>, and a change period of the grinding stone feed amount is 45 ° or 120 °, respectively.

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