JP2018039730A - Silicon carbide ingot, and silicon carbide substrate manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a silicon carbide ingot capable of suppressing the warpage of a substrate in the case where it is cut by using a wire saw according to a stationary abrasive grain process, and a silicon carbide substrate manufacturing method to be executed by using said silicon carbide ingot.SOLUTION: A silicon carbide ingot 1 has an end face 1a and an end face 1b, which is an end face on the side opposed to the end face 1a. In the silicon carbide ingot 1, the gradient of nitrogen concentration in a growth direction, which is a direction in which the end face 1a and the end face 1b confront, is 1×10cmor more to 1×10cmor less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a silicon carbide ingot and a method for manufacturing a silicon carbide substrate, and more particularly, a silicon carbide ingot capable of suppressing warpage of a substrate when cut using a wire saw of a fixed abrasive method and the silicon carbide ingot The present invention relates to a method for manufacturing a silicon carbide substrate that is performed using a silicon carbide ingot.

  Conventionally, silicon carbide ingots have been cut using a wire saw by a free abrasive grain method. For example, Japanese Unexamined Patent Application Publication No. 2010-23208 discloses a workpiece cutting method using a slurry containing GC abrasive grains. On the other hand, in recent years, cutting of silicon carbide ingots using a wire saw by a fixed abrasive method has also been carried out. Thereby, the cost in the cutting process of the silicon carbide ingot can be greatly reduced as compared with the case of employing the free abrasive grain method.

JP 2010-23208 A

  When the substrate is obtained by cutting the silicon carbide ingot using the fixed abrasive method as described above, the occurrence of warping can be suppressed to some extent even in a large-diameter substrate. However, there are cases where a plurality of substrates obtained from one silicon carbide ingot include a substrate having a small warp and a substrate having a large warp and not suitable for practical use.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a silicon carbide ingot capable of suppressing warpage of a substrate when the wire saw is cut using a fixed abrasive method, and the silicon carbide ingot. It is providing the manufacturing method of the silicon carbide board | substrate implemented using this.

A silicon carbide ingot according to the present invention has a first end surface and a second end surface that is an end surface opposite to the first end surface. In the silicon carbide ingot, the gradient of the nitrogen concentration in the growth direction, which is the direction in which the first end face and the second end face face each other, is 1 × 10 ¹⁶ cm ⁻⁴ or more and 1 × 10 ¹⁸ cm ⁻⁴ or less. .

  According to the present invention, there is provided a silicon carbide ingot capable of suppressing warpage of a substrate when cut using a wire saw of a fixed abrasive method, and a method for manufacturing a silicon carbide substrate implemented using the silicon carbide ingot. Can be provided.

It is a schematic front view which shows the silicon carbide ingot which concerns on this embodiment. It is a schematic perspective view which shows the silicon carbide substrate which concerns on this embodiment. It is the schematic for demonstrating the calculation method of the gradient of the nitrogen concentration in the silicon carbide ingot which concerns on this embodiment. It is a flowchart which shows roughly the manufacturing method of the silicon carbide ingot and silicon carbide substrate which concern on this embodiment. It is a schematic sectional drawing for demonstrating the manufacturing method of the silicon carbide ingot which concerns on this embodiment. It is a schematic perspective view which shows the structure of the wire saw used in the manufacturing method of the silicon carbide substrate which concerns on this embodiment.

[Description of Embodiment of Present Invention]
First, the contents of the embodiments of the present invention will be listed and described.

(1) The silicon carbide ingot (1) according to the present embodiment has a first end face (1a) and a second end face (1b) which is an end face opposite to the first end face (1a). Yes. In the silicon carbide ingot (1), the gradient of the nitrogen concentration in the growth direction, which is the direction in which the first end face (1a) and the second end face (1b) face each other, is 1 × 10 ¹⁶ cm ⁻⁴ or more and 1 × 10 ^18. It is below cm ⁻⁴ .

In the silicon carbide ingot (1), the gradient of the nitrogen concentration in the growth direction is as high as 1 × 10 ¹⁶ cm ⁻⁴ or more. Therefore, when the said silicon carbide ingot (1) is cut | disconnected by making it drive | work while making the wire to which the abrasive grain was fixed contact the some cutting | disconnection part arrange | positioned along the said growth direction of a silicon carbide ingot (1). The warp of the substrate can be suppressed when any part of the plurality of cutting parts is cut. In the silicon carbide ingot (1), the gradient of the nitrogen concentration in the growth direction is suppressed to 1 × 10 ¹⁸ cm ⁻⁴ or less. Therefore, it is possible to suppress the occurrence of cracks in the crystal due to an excessive nitrogen concentration gradient. Therefore, according to the said silicon carbide ingot (1), when it cut | disconnects using the wire saw by a fixed abrasive method, the curvature of a board | substrate can be suppressed.

  (2) The silicon carbide ingot (1) has a width of 100 mm or more when viewed from the growth direction. When the width of the silicon carbide ingot (1) is large, the width of the silicon carbide substrate (10) obtained by cutting is also large. And when the width | variety of a silicon carbide substrate (10) is large, the curvature of a board | substrate will generate | occur | produce more easily. Therefore, when the width when viewed from the growth direction of the silicon carbide ingot (1) is 100 mm or more, the effect of suppressing the warpage of the substrate is further increased.

  (3) In the silicon carbide ingot (1), the nitrogen concentration changes monotonously in the growth direction. This makes it easier to adjust the flow rate of nitrogen gas when manufacturing the silicon carbide ingot (1). Note that “the nitrogen concentration in the growth direction monotonously changes” means a case where the nitrogen concentration linearly increases or decreases so as to have a certain slope in the growth direction.

  (4) In the silicon carbide ingot (1), one of the first end surface (1a) and the second end surface (1b) is a surface including the (000-1) surface. Thereby, a silicon carbide single crystal can be easily grown along the c-axis direction when manufacturing the silicon carbide ingot (1).

  (5) A method for manufacturing a silicon carbide substrate according to the present embodiment includes a step of preparing the silicon carbide ingot (1) and a step of cutting the silicon carbide ingot (1) to obtain a silicon carbide substrate (10). I have.

In the silicon carbide ingot (1), the gradient of the nitrogen concentration in the growth direction is as high as 1 × 10 ¹⁶ cm ⁻⁴ or more. Therefore, when the silicon carbide ingot (1) is cut by running the wire on which the abrasive grains are fixed in contact with the plurality of cutting portions arranged along the growth direction of the silicon carbide ingot (1). The warp of the substrate can be suppressed regardless of which portion of the plurality of cut portions is cut. Further, in the silicon carbide ingot (1), the gradient of the nitrogen concentration in the growth direction is suppressed to 1 × 10 ¹⁸ cm ⁻⁴ or less. Therefore, generation of cracks can be suppressed in the substrate obtained by cutting silicon carbide ingot (1). Therefore, according to the method for manufacturing a silicon carbide substrate according to the present embodiment, warping of the substrate can be suppressed when the silicon carbide ingot is cut using a wire saw of a fixed abrasive method.

  (6) In the silicon carbide substrate manufacturing method, in the step of obtaining the silicon carbide substrate (10), the wire (34) having abrasive grains fixed on the surface is disposed along the growth direction of the silicon carbide ingot (1). The silicon carbide ingot (1) is cut by running while contacting the plurality of cut portions. Thus, when a silicon carbide ingot (1) is cut | disconnected by employ | adopting a fixed abrasive system, the curvature of a board | substrate can be suppressed as mentioned above.

  (7) In the method for manufacturing the silicon carbide substrate, in the silicon carbide ingot (1), the nitrogen concentration in the portion on the second end face (1b) side is higher than the nitrogen concentration in the portion on the first end face (1a) side. ing. And the 2nd cutting part located in the 2nd end face (1b) side among the above-mentioned cutting parts in the 1st cutting located in the 1st end face (1a) side among the above-mentioned cutting parts The portion on the downstream side in the traveling direction of the wire (34) contacts the portion.

  The downstream portion of the wire (34) has a greater degree of deterioration than the upstream portion, and the substrate obtained by cutting with the downstream wire portion is more likely to warp. On the other hand, the curvature of a board | substrate can be suppressed more by making the said wire part of the said downstream contact the cutting part located in the 2nd end surface (1b) side with high nitrogen concentration.

(8) In the method for manufacturing the silicon carbide substrate, the abrasive grains include diamond abrasive grains.
By using the wire to which the hard abrasive grains are thus fixed, the silicon carbide ingot (1) can be cut more efficiently.

  (9) In the method for manufacturing the silicon carbide substrate, in the step of obtaining the silicon carbide substrate (10), the silicon carbide ingot (1) is cut so that the thickness of the silicon carbide substrate (10) is 1 mm or less.

  When the thickness of the silicon carbide substrate (10) is small, the warpage of the substrate is more likely to occur. Therefore, when silicon carbide ingot (1) is cut so that the thickness of silicon carbide substrate (10) is 1 mm or less, the effect of suppressing warpage of the substrate is further increased.

[Details of the embodiment of the present invention]
Next, specific examples of embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated. In the present specification, the individual orientation is indicated by [], the collective orientation is indicated by <>, the individual plane is indicated by (), and the collective plane is indicated by {}. As for the negative index, “−” (bar) is added on the number in crystallography, but in this specification, a negative sign is attached before the number.

  First, a silicon carbide ingot and a silicon carbide substrate according to the present embodiment will be described. Referring to FIG. 1, silicon carbide ingot 1 is made of silicon carbide having a polytype of 4H type, and mainly includes seed substrate 11 and silicon carbide layer 13. Silicon carbide ingot 1 has an end surface 1a (first end surface) on the seed substrate 11 side and an end surface 1b (second end surface) on the silicon carbide layer 13 side. Silicon carbide layer 13 contains nitrogen (N) atoms, and is formed by growing on surface 11a of seed substrate 11 by a sublimation recrystallization method. The growth direction of silicon carbide layer 13 (the direction in which end face 1a and end face 1b face each other) is the <0001> direction, and end face 1b, which is the growth face, is a (000-1) plane. Referring to FIG. 2, silicon carbide substrate 10 according to the present embodiment is obtained by cutting silicon carbide ingot 1 (see FIG. 1) in an arbitrary direction. Although silicon carbide ingot 1 having seed substrate 11 and silicon carbide layer 13 is shown in FIG. 1, seed substrate 11 may be removed from silicon carbide ingot 1.

  Referring to FIG. 1, the thickness of silicon carbide ingot 1 in the growth direction is, for example, 10 mm or more. The width when viewed from the growth direction of silicon carbide ingot 1 is 100 mm or more, preferably 150 mm or more. Referring to FIG. 2, silicon carbide substrate 10 has a thickness of 1 mm or less. Similar to the width of silicon carbide ingot 1, silicon carbide substrate 10 has a width of 100 mm or more (4 inches or more), preferably 150 mm or more (6 inches or more).

Referring to FIG. 1, the nitrogen concentration in silicon carbide layer 13 is, for example, 1 × 10 ¹⁴ cm ⁻³ or more and 3 × 10 ¹⁹ cm ⁻³ or less, and preferably 1 × 10 ¹⁷ cm ⁻³ or more and 2 ×. 10 ¹⁹ cm ⁻³ or less. In silicon carbide layer 13, the gradient of nitrogen concentration in the growth direction is 1 × 10 ¹⁶ cm ⁻⁴ or more and 1 × 10 ¹⁸ cm ⁻⁴ or less, preferably 1 × 10 ¹⁷ cm ⁻⁴ or more and 1 × 10 ¹⁸ cm. ⁻⁴ or less, more preferably 5 × 10 ¹⁷ cm ⁻⁴ or more and 1 × 10 ¹⁸ cm ⁻⁴ or less.

The gradient of the nitrogen concentration in the growth direction of silicon carbide ingot 1 can be calculated as follows. Referring to FIG. 3, first, a point 2 mm away from end face 1b in the growth direction in silicon carbide layer 13 is defined as first measurement point 21, and a point 5 mm away from first measurement point 21 in the growth direction is a second measurement point. 22 First measurement point 21 and second measurement point 22 include a central portion in the radial direction of silicon carbide ingot 1. Next, the nitrogen concentration (cm ⁻³ ) is measured at each of the first measurement point 21 and the second measurement point 22. The measurement of the nitrogen concentration is carried out by, for example, secondary ion mass spectrometry (SIMS; Secondary Ion Mass Spectrometry). Then, the absolute value of the difference (cm ⁻³ ) in nitrogen concentration measured at each of the first measurement point 21 and the second measurement point 22 is the distance between the first measurement point 21 and the second measurement point 22. (0.5 cm). In this way, the gradient (cm ⁻⁴ ) of the nitrogen concentration in the growth direction of the silicon carbide ingot 1 can be calculated.

  In the silicon carbide ingot 1, the nitrogen concentration changes monotonously in the growth direction as schematically shown in the graph in FIG. More specifically, the nitrogen concentration increases linearly from the end face 1a side to the end face 1b side. Thus, in silicon carbide ingot 1, the nitrogen concentration in the portion on the end face 1b side is higher than the nitrogen concentration in the portion on the end face 1a side. In the graph of FIG. 3, the horizontal axis indicates the nitrogen concentration, and the vertical axis indicates the growth direction.

  Next, a method for manufacturing the silicon carbide ingot and the silicon carbide substrate according to the present embodiment will be described. In the method for manufacturing the silicon carbide ingot and the silicon carbide substrate according to the present embodiment, the silicon carbide ingot 1 and the silicon carbide substrate 10 are obtained as described below.

  With reference to FIG. 4, first, a seed substrate and a raw material preparation process are implemented as process (S10). In this step (S10), referring to FIG. 5, first, seed substrate 11 made of silicon carbide single crystal and raw material 12 made of polycrystalline silicon carbide powder or silicon carbide sintered body are prepared. And the seed substrate 11 and the raw material 12 are arrange | positioned in the state which mutually opposed inside the crucible 2 made from carbon, as shown in FIG.

  Next, a temperature raising step is performed as a step (S20). In this step (S <b> 20), referring to FIG. 5, first, argon (Ar) gas as a carrier gas is supplied into the crucible 2. And the inside of the crucible 2 is heated to the temperature of 2000 degreeC or more and 2500 degrees C or less with a heating coil (not shown). At this time, the inside of the crucible 2 is heated so that the temperature decreases in a direction from the side where the raw material 12 is disposed toward the side where the seed substrate 11 is disposed (so that a temperature gradient is formed).

  Next, a crystal growth step is performed as a step (S30). In this step (S30), the inside of the crucible 2 is depressurized to a predetermined pressure while supplying argon gas. Thereby, raw material 12 is sublimated to generate silicon carbide source gas, and silicon carbide layer 13 grows as the source gas is solidified on seed substrate 11. Nitrogen gas, which is a dopant gas, is also supplied into the crucible 2 together with argon gas. Then, nitrogen atoms generated by thermally decomposing nitrogen gas are taken into the growing silicon carbide layer 13 as a dopant. Thus, in the step (S30), the silicon carbide layer 13 containing nitrogen atoms is grown on the surface 11a on the seed substrate 11 by sublimating the raw material 12 while supplying nitrogen gas and argon gas. The silicon carbide ingot 1 is prepared by performing the steps (S10) to (S30).

  Next, a cutting step is performed as a step (S40). In this step (S40), referring to FIG. 6, silicon carbide ingot 1 is cut to a predetermined thickness using wire saw 3. Thereby, a plurality of silicon carbide substrates 10 (FIG. 2) having a predetermined thickness are obtained from silicon carbide ingot 1. First, the structure of the wire saw 3 will be described with reference to FIG.

  The wire saw 3 mainly has a jig 30 (main body portion 31 and holding portion 32), a set of rollers 33, a wire 34, and a cutting fluid supply portion 35. The roller 33 has a cylindrical shape, and is arranged side by side with a predetermined distance from the other roller 33. The roller 33 is rotatable around a cylindrical central axis as indicated by an arrow in FIG.

  The wire 34 is an electrodeposited diamond wire in which diamond abrasive grains are fixed to the surface of, for example, a piano wire by electrodeposition. The diameter of the wire 34 is, for example, 250 μm. As shown in FIG. 6, the wire 34 is wound around the outer peripheral surface of each of the pair of rollers 33 a plurality of times. The tension of the wire 34 is 45N, for example. As a result, the wire 34 can travel from the upstream U (left side in FIG. 6) to the downstream D (right side in FIG. 6) while reciprocating between the one roller 33 and the other roller 33. Yes.

  The cutting fluid supply unit 35 is disposed above the wire 34. The cutting fluid supply unit 35 supplies cutting oil (coolant) from above the wire 34.

  Jig 30 includes a main body portion 31 and a holding portion 32, and holds silicon carbide ingot 1 that is an object to be cut in holding portion 32. Jig 30 is movable in a direction approaching wire 34 or a direction retracting from wire 34 while holding silicon carbide ingot 1 in holding portion 32.

  Next, the cutting procedure of the silicon carbide ingot 1 using the wire saw 3 will be described. Referring to FIG. 6, first, silicon carbide ingot 1 prepared in the above steps (S10) to (S30) is placed on jig 30 such that a part of the outer peripheral surface thereof contacts holding portion 32. At this time, in the silicon carbide ingot 1, the portion on the end surface 1b side where the nitrogen concentration is relatively high is located on the downstream side D (right side in FIG. 6) of the wire 34, and the portion on the end surface 1a side where the nitrogen concentration is relatively low It is installed so as to be located on the upstream side U (left side in FIG. 6) of the wire 34.

  Next, by rotating the roller 33, the wire 34 travels from the upstream U (left side in FIG. 6) toward the downstream D (right side in FIG. 6) while reciprocating between the rollers 33. Thereby, wire 34 travels along the growth direction of silicon carbide ingot 1 (the direction in which end surface 1a and end surface 1b face each other). The average value of the linear speed (traveling speed) of the wire 34 is, for example, 1000 m / min.

  Next, the silicon carbide ingot 1 is brought into contact with the wire 34 by lowering the jig 30 toward the wire 34. At this time, since the wire 34 is provided so as to reciprocate between the rollers 33, the silicon carbide ingot 1 comes into contact with the wire 34 at a plurality of cutting portions arranged along the growth direction. Here, the interval between the cut portions in the silicon carbide ingot 1 corresponds to the interval between the wires 34 straddling the roller 33. Further, as described above, the silicon carbide ingot 1 has the end surface 1b side where the nitrogen concentration is relatively high positioned on the downstream side D of the wire 34 and the end surface 1a side where the nitrogen concentration is relatively low positioned on the upstream side U of the wire 34. To be installed. Therefore, in the silicon carbide ingot 1, a portion (second cutting portion) located on the end surface 1b side among the plurality of cutting portions is a portion (first cutting portion) located on the end surface 1a side among the plurality of cutting portions. The downstream side in the traveling direction of the wire 34 is in contact with the cutting portion).

  Next, the wire 34 is caused to travel from the upstream side U toward the downstream side D while being brought into contact with the plurality of cut portions arranged along the growth direction of the silicon carbide ingot 1, and the silicon carbide ingot 1 is further lowered. To proceed with cutting. The average value of the cutting speed is, for example, 250 μm / min. Thus, a plurality of silicon carbide substrates 10 (FIG. 2) are obtained by cutting silicon carbide ingot 1 at a plurality of cutting portions. Silicon carbide substrate 10 has a thickness of, for example, 1 mm or less. By performing the above steps (S10) to (S40), silicon carbide ingot 1 (FIG. 1) and silicon carbide substrate 10 (FIG. 2) according to the present embodiment are obtained, and silicon carbide according to the present embodiment is obtained. The manufacturing method of the ingot and the silicon carbide substrate is completed.

An experiment for confirming the effect of the present invention was performed for suppressing the warpage of the substrate when the silicon carbide ingot was cut using a wire saw by a fixed abrasive grain method. First, the silicon carbide ingot according to the present embodiment was prepared. In the silicon carbide ingot, the nitrogen concentrations at the first measurement point 21 and the second measurement point 22 (FIG. 3) were 8.72 × 10 ¹⁷ cm ⁻³ and 8.20 × 10 ¹⁷ cm ⁻³ , respectively (Example) ). In addition, as a comparative example, it was also prepared silicon carbide ingot nitrogen concentration in the first measurement point 21 and the second measuring point 22 are each 8.05 × ¹⁰ 17 ^{cm -3} and 8.03 × ¹⁰ 17 ^{cm -3.} The thicknesses of the silicon carbide ingots of the example and the comparative example were each 10 mm. These silicon carbide ingots were cut in the same manner as in the method for manufacturing the silicon carbide substrate according to the present embodiment. Thereby, a plurality of silicon carbide substrates having a thickness of 1 mm were obtained, and the warpage of each silicon carbide substrate was measured. Table 1 has shown the measurement result of the curvature in an Example (No. 1-9) and a comparative example (No. 10-18). In Table 1, the numbers (No.) of the silicon carbide substrates are sequentially given in the growth direction of the silicon carbide ingot. Nos. 1 and 10 are substrates obtained by cutting the seed substrate side. 9 and 18 are silicon carbide substrates obtained by cutting the growth surface side. That is, no. Nos. 1 and 10 are substrates obtained by cutting a silicon carbide substrate with upstream wires. This is a substrate obtained by cutting a silicon carbide substrate close to the numbers 9 and 18 with a downstream wire.

  As is clear from Table 1, in the comparative examples (Nos. 10 to 18), the warpage of the substrate (the substrate close to the number of No. 18) obtained by cutting with the downstream wire is cut with the upstream wire. In contrast to the warpage of the substrate (the substrate close to the number of No. 10) obtained in this way, the warpage increased more in the examples (No. 1 to 9) than in the comparative example. It has become smaller. Therefore, it has been found that by controlling the gradient of the nitrogen concentration in the growth direction of the silicon carbide ingot, it is possible to suppress the warpage of the substrate during cutting by the fixed abrasive method.

  The embodiments and examples disclosed herein are illustrative in all respects and should not be construed as being restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The silicon carbide ingot and the silicon carbide substrate manufacturing method of the present invention use a silicon carbide ingot and the silicon carbide ingot that are required to suppress warping of the substrate when cut using a wire saw by a fixed abrasive method. The method for manufacturing a silicon carbide substrate to be implemented can be applied particularly advantageously.

DESCRIPTION OF SYMBOLS 1 Silicon carbide ingot 1a, 1b End surface 2 Crucible 3 Wire saw 10 Silicon carbide substrate 11 Seed substrate 11a Surface 12 Raw material 13 Silicon carbide layer 21 1st measurement point 22 2nd measurement point 30 Jig 31 Main body part 32 Holding part 33 Roller 34 Wire 35 Cutting fluid supply unit

Claims (10)

A first end face that is a (0001) plane, an end face opposite to the first end face, and a second end face that is a (000-1) plane,
The nitrogen concentration in the portion on the second end face side is higher than the nitrogen concentration in the portion on the first end face side,
The first end surface and the second end surface face each other, and the gradient of the nitrogen concentration in the growth direction which is the <0001> direction is 1 × 10 ¹⁶ cm ⁻⁴ or more and 1 × 10 ¹⁸ cm ⁻⁴ or less. Yes,
A silicon carbide ingot whose polytype of silicon carbide is 4H type.   The silicon carbide ingot according to claim 1 whose width when seen from said growth direction is 100 mm or more.   The silicon carbide ingot according to claim 1 or 2, wherein the nitrogen concentration changes monotonously in the growth direction.   4. The silicon carbide ingot according to claim 1, wherein in the growth direction, a nitrogen concentration increases linearly from the first end face side toward the second end face side. 5.   The silicon carbide ingot according to any one of claims 1 to 4, wherein the second end surface is a growth surface. Preparing the silicon carbide ingot according to any one of claims 1 to 5,
And a step of cutting the silicon carbide ingot to obtain a silicon carbide substrate.   In the step of obtaining the silicon carbide substrate, the silicon carbide ingot is moved by causing a wire having abrasive grains fixed on the surface to run while contacting a plurality of cut portions arranged along the growth direction of the silicon carbide ingot. The method for manufacturing a silicon carbide substrate according to claim 6, wherein the silicon carbide substrate is cut.   Of the plurality of cutting portions, the second cutting portion positioned on the second end surface side is more preferably connected to the wire than the first cutting portion positioned on the first end surface side among the plurality of cutting portions. The method for manufacturing a silicon carbide substrate according to claim 7, wherein a downstream portion in the traveling direction is in contact.   The method for manufacturing a silicon carbide substrate according to claim 7, wherein the abrasive grains include diamond abrasive grains.   The silicon carbide substrate according to any one of claims 6 to 9, wherein, in the step of obtaining the silicon carbide substrate, the silicon carbide ingot is cut so that the thickness of the silicon carbide substrate is 1 mm or less. Production method.

Images