Semiconductor device and semiconductor wafer

Abstract

To provide a semiconductor device and a semiconductor wafer that are capable of suppressing the development of cracks generated in a scribe line during processing the semiconductor device or the semiconductor wafer.SOLUTION: A semiconductor device comprises a semiconductor substrate which has one surface of which elements are formed and which is made of silicon carbide, a peripheral part which is disposed on a predetermined area around the semiconductor substrate and on which elements are not formed, a plurality of trenches or a portion of the trenches in which a material with a coefficient of thermal expansion different from the silicon carbide is filled.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a semiconductor device and a semiconductor wafer. [Background technology]

[0002] In the manufacture of semiconductor devices, it is common to provide a formation region for a plurality of semiconductor devices (chips) on a semiconductor wafer, manufacture them collectively, and when the semiconductor devices are completed, scribe or dicing the semiconductor wafer to separate them into individual semiconductor devices. When scribing a semiconductor wafer, a region to be a cutting margin is required, and this cutting margin, which becomes a dividing line that divides the semiconductor devices on the semiconductor wafer, is generally called a scribe line. Various studies have been conducted on scribing, and it has become a technical field in its own right.

[0003] As an example of a conventional technique related to scribing, Patent Document 1 can be mentioned. The semiconductor integrated circuit device according to Patent Document 1 has an upper buried wiring layer on a multi-layer buried wiring layer, and has a metal seal ring that is ring-shaped along the edge of a semiconductor substrate. In the semiconductor integrated circuit device according to Patent Document 1, the upper buried wiring layer has a lower main insulating film, an etch stop insulating layer thereon, and an upper main insulating film, and a crack guiding ring having an air gap is provided in the upper main insulating film buried region formed by the opening of the etch stop insulating layer and the recess on the upper surface of the lower main insulating film below it in the outer region of the metal seal ring. Patent Document 1 claims that the semiconductor integrated circuit device having such a configuration can prevent cracks caused by chip division processing such as dicing from reaching the inside of the chip beyond the seal ring while avoiding an increase in process cost. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-103339 A Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, silicon carbide (hereinafter, "SiC") has become increasingly popular as a material for semiconductor wafers. As a substance, SiC is highly hard, highly heat-resistant, and chemically stable. High-purity SiC has a higher thermal conductivity than Si (silicon), and because of its wide band gap, it is used in blue light-emitting diodes and MOSFETs (Metal Oxide Semiconductors).

[0006] On the other hand, SiC is a harder and more brittle material than Si, and has poor machinability, which has led to the problem of chipping due to pressure when scribing SiC wafers or application of force from the periphery of a SiC chip when handling it. Chipping refers to chipping of the outer periphery of the chip (including the area left uncut by the scribe line). Chipping can cause problems such as a decrease in the voltage resistance of the SiC chip. Once a crack occurs due to pressure applied when scribing the SiC wafer or the application of force from the outer periphery of the chip when handling the SiC chip, the crack may grow depending on the subsequent handling and may reach the active area (element area) of the SiC chip. In other words, while SiC chips have the advantage of maintaining their voltage resistance even in conditions where the electric field is about 10 times higher than that of Si chips, they have the characteristic that their circuit function is easily affected by chipping from the outer periphery of the chip.

[0007] In this regard, Patent Document 1 also addresses the issue of cracks that occur during dicing, and provides a crack induction ring with an air gap in the upper main insulating film buried region formed by the recess; however, this is not based on the technical idea of ​​suppressing the progression of the crack by taking into account the characteristics of the recess itself and the direction of the crack.

[0008] In view of the above circumstances, an object of the present invention is to provide a semiconductor device and a semiconductor wafer capable of suppressing the progression of cracks that occur in scribe lines during handling of the semiconductor device or semiconductor wafer. [Means for solving the problem]

[0009] In order to solve the above problems, the semiconductor device of the present invention includes a semiconductor substrate made of silicon carbide having elements formed on one surface thereof, a peripheral portion in which the elements are not formed and disposed in a predetermined region around the semiconductor substrate, and a plurality of trenches or portions of trenches formed in the peripheral portion and filled with a material having a thermal expansion coefficient different from that of silicon carbide.

[0010] In order to solve the above problems, another form of the semiconductor device according to the present invention is a semiconductor device including a semiconductor substrate made of silicon carbide having an element formed on one surface and a crystal structure of 4H-SiC having a rectangular shape in a planar view, a peripheral portion in which the element is not formed and disposed in a predetermined region around the semiconductor substrate, and a plurality of trenches or portions of trenches formed in the peripheral portion and having a polygonal shape in a planar view, wherein one side of the semiconductor substrate is parallel to the direction of the crystal axis of the crystal structure, and at least one side of the trench in the planar view is perpendicular to the direction of the crystal axis.

[0011] In order to solve the above problems, a semiconductor wafer according to the present invention is a semiconductor wafer made of silicon carbide having a plurality of semiconductor devices formed on one side thereof, and includes scribe lines that separate the semiconductor devices, and a plurality of trenches formed within the scribe lines and filled with a material having a thermal expansion coefficient different from that of silicon carbide. Effect of the Invention

[0012] According to the present invention, it is possible to provide a semiconductor device and a semiconductor wafer capable of suppressing the progression of cracks that occur in the scribe line during handling of the semiconductor device or semiconductor wafer. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1A is a plan view and a side view showing an example of a configuration of a semiconductor device according to a first embodiment, and FIG. 1B is a plan view of a semiconductor wafer according to the first embodiment. [Diagram 2] FIG. 2 is a plan view showing an example of a configuration of a partial wafer according to the first embodiment. [Diagram 3] FIG. 1A is a cross-sectional view taken along a cutting line of a semiconductor wafer according to a first embodiment, and FIG. 1B is a plan view for explaining the effect of a trench in stopping cracks. [Figure 4] FIG. 11 is a plan view showing an example of a configuration of a partial wafer according to a second embodiment. [Diagram 5] FIG. 13A is a diagram for explaining the crystal structure of SiC, and FIG. 13B is a diagram for explaining the relationship between the shape of a trench according to the second embodiment and the direction of the crystal axis of SiC. [Figure 6] FIG. 13 is a plan view showing an example of a configuration of a partial wafer according to a third embodiment. [Figure 7] 13 is a diagram showing the relationship between the shape of a trench and the direction of a crystal axis of SiC according to the third embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0015] [First embodiment] 1 to 3, a semiconductor device 10 and a semiconductor wafer 20 according to the present embodiment will be described. <1> As shown in FIG. 1(b), the semiconductor device 10 includes a semiconductor substrate 11 made of SiC, an element region 24, a peripheral portion 26, and an isolated trench 12. As shown in FIG. 1(b), a plurality of semiconductor devices 10 are formed on a semiconductor wafer 20, the semiconductor devices 10 being partitioned by scribe lines SL.

[0016] The element region 24 is a region in which various elements (e.g., circuit elements) that fulfill the functions of the semiconductor device 10 are formed. The peripheral edge portion 26 is a region of the scribe lines SL that remain partially when the semiconductor wafer 20 is cut along the scribe lines SL. The trenches 12 are as shown in FIG. <2> As shown in FIG. 1(a), the insulating layer 14 is formed at a predetermined depth from one surface of the semiconductor substrate 11, and the inside is filled with a material (not shown) having a thermal expansion coefficient different from that of SiC. <1> 2, the plurality of trenches 12 are formed along the entire periphery of the peripheral portion 26 in plan view of the semiconductor device 10. As shown in FIG.

[0017] As shown in FIG. 1(b), the semiconductor devices 10 formed on the semiconductor wafer 20 are partitioned from one another at intervals of scribe lines SL. Each side of the rectangular semiconductor device 10 is arranged parallel to the X-axis or Y-axis. An orientation flat (hereinafter, "orientation flat") 22 arranged parallel to the X-axis direction is a mark indicating the direction of the crystal axis. In this embodiment, SiC with a 4H-SiC crystal structure is used as the semiconductor wafer 20. The orientation flat 22 indicates the direction of one of the crystal axes (a1 axis, a2 axis, a3 axis) of SiC. In this embodiment, one side of the rectangular semiconductor device 10 is arranged parallel to the orientation flat 22, so that one side of the semiconductor device 10 is arranged parallel to the crystal axis of the semiconductor wafer 20.

[0018] As described above, in the semiconductor device or semiconductor wafer according to the conventional technology, it is required to suppress the progression of cracks that occur in the scribe line during handling. Therefore, in the semiconductor device 10 and semiconductor wafer 20 according to the present embodiment, a plurality of trenches 12 are densely formed inside the scribe line SL, and further, the inside of the trenches 12 is filled with a material having a thermal expansion coefficient different from that of SiC.

[0019] The configuration of the scribe lines SL of the semiconductor wafer 20 will be described in more detail with reference to Fig. 2. Fig. 2 shows a part of the semiconductor wafer 20 (hereinafter, "partial wafer") shown in Fig. 1(b), and shows four semiconductor devices 10 together with the scribe lines SL. Strictly speaking, the semiconductor device 10 includes the peripheral portion 26, but in FIG. 2, the region corresponding to the element region 24 is shown as the semiconductor device 10 to avoid the diagram becoming complicated. The same applies to the partial wafers shown below. As shown in FIG. 2, scribe lines SL extending in the X-axis direction and the Y-axis direction are provided between the semiconductor devices 10, and a plurality of trenches 12 are densely formed inside the scribe lines SL. The trenches 12 according to this embodiment are substantially square. In this embodiment, the width of the scribe lines SL is, for example, 100 μm, the length of one side of the trenches 12 is several μm, and the depth of the trenches 12 is 1 μm to 2 μm. Therefore, the trenches 12 can be densely arranged on the scribe lines SL. However, the width of the scribe lines SL and the size of the trenches 12 are not limited to these, and appropriate values ​​can be selected in consideration of the size of the semiconductor wafer 20, the size of the semiconductor device 10, and the like so that cracks occurring mainly in the scribe lines SL can be effectively stopped as described in detail below.

[0020] The cutting region CL shown in FIG. 2 indicates a region that is actually cut when the semiconductor wafer 20 is scribed and does not remain in the semiconductor device 10. The region of the scribe line SL excluding the cutting region CL is the peripheral portion 26. The region of the semiconductor device 10 other than the peripheral portion 26 is the element region 24 (not shown). The element region 24 may include not only the region where the element is actually formed, but also a buffer region where no element is formed, which is provided to mitigate the effect of cracks, for example. When the semiconductor wafer 20 is scribed along the scribe line SL, the trench 12 or a part of the trench 12 remains in the peripheral portion 26. In other words, the trench 12 is arranged so close to the element region 24 that it remains in the peripheral portion 26. Note that FIG. 2 illustrates a configuration in which the trench 12 is arranged over the entire region of the scribe line SL, but is not limited to this, and for example, the trench 12 may not be arranged in the cutting region CL.

[0021] The function of the trench 12 according to this embodiment will be described with reference to Fig. 3. Fig. 3(a) is a cross-sectional view taken along the line XX' shown in Fig. 2, that is, a cross-sectional view taken at the cutting region CL, and shows that a trench 12 of a predetermined depth is formed on one side of the semiconductor wafer 20. In other words, Fig. 3(a) is the same as Fig. 1(a). <2> I see the same side. The inside of trench 12 is filled with a material (hereinafter sometimes referred to as a "filling material") having a thermal expansion coefficient different from that of SiC, for example, an oxide film.

[0022] Since the trench 12 according to the present embodiment has the above-mentioned configuration, when a heat treatment is performed in another step after the trench 12 is formed in the manufacturing process of the semiconductor wafer 20, the material inside the trench 12 undergoes a thermal expansion amount different from that of SiC. This causes crack-like damage (e.g., crystal defects) to occur in a part of the trench 12. This damage is likely to occur at the corners of the approximately square trench 12. This is because stress caused by the difference in thermal expansion between SiC and the filling material tends to concentrate at the corners of the trench 12. In addition, taking into consideration the susceptibility of damage to occur in the trench 12, it is preferable to make the thermal expansion coefficient of the filling material larger than that of SiC.

[0023] FIG. 3( b ) shows a schematic diagram of a state in which damage 16 occurs at the corner of the trench 12 . In FIG. 3(b), the damage 16 is thinned out for ease of viewing, but in reality, damage 16 occurs at almost all corners. As shown in FIG. 3(b), when a crack 18A (hereinafter, when the crack is not distinguished, it is referred to as "crack 18") occurs during scribing of the semiconductor wafer 20 or handling of the semiconductor wafer 20, the crack 18A stops (terminates) at the damage 16 present in the direction of progression of the generated crack 18A. FIG. 3(b) shows an example in which a part of the trench 12 remains at the peripheral portion 26, but by making the size of the trench 12 smaller, a large number of intact trenches 12 remain at the peripheral portion 26, and more damage 16 can be arranged. This makes it possible to deal with more directions of progression of cracks.

[0024] In particular, even if cracks 18 occur during handling of the chips after semiconductor wafer 20 has been diced into semiconductor devices 10, the occurrence of cracks 18 is stopped by damage 16 in the same manner as the action of damage 16 in the manufacturing process of semiconductor wafer 20. Furthermore, in semiconductor device 10 of this embodiment, there is a high possibility that cracks 18 occurring in scribe lines SL in the manufacturing process of semiconductor wafer 20 have been effectively stopped, and therefore it is considered that there is a low possibility that new cracks 18 will occur in the state of semiconductor device 10.

[0025] It should be noted that the crack 18 that occurs in the scribe line SL may be stopped not only by the damage 16 but also by the surface of the trench 12. The crack 18B shown in Fig. 3(b) is stopped by the surface of the trench 12. Details of the form in which the crack 18 is stopped on the surface of the trench 12 will be described later.

[0026] Next, an outline of a method for manufacturing the semiconductor device 10 and the semiconductor wafer 20 according to the present embodiment will be described.

[0027] (1) Trench formation A trench is formed in the scribe line SL of the semiconductor wafer 20. As described above, the trench 12 may be formed only in the region corresponding to the peripheral portion 26 (region to be the peripheral portion), and not in the cutting region CL. When the trench 12 is substantially square in shape, the side length is several μm, and the depth is 1 μm to 2 μm, for example. When the trench 12 is rectangular in shape, the short side is several μm or more, for example. This is because if the width of the trench 12 is narrow, there is a possibility that the filler material will not be embedded in the entire interior of the trench 12.

[0028] (2) Oxide film formation Next, a filling material is embedded inside the trench 12. The filling material is, for example, an oxide film. For example, the oxide film includes SiO2.

[0029] (3) Heat treatment Next, a heat treatment for activating the diffusion layer is performed at a temperature of, for example, 1200° C. to 1700° C. In this heat treatment process, damage 16 occurs.

[0030] (4) Scribe The semiconductor wafer 20 is scribed along the scribe lines SL, and is separated into individual semiconductor devices 10. At this time, the trenches 12 or parts of the trenches 12 remain on the peripheral portion 26 of the semiconductor device 10.

[0031] (5) Assembly Next, assembly such as mounting the semiconductor device 10 in a package is performed.

[0032] As described above in detail, the semiconductor device 10 and semiconductor wafer 20 according to the present embodiment make it possible to suppress the progression of cracks that occur in the scribe lines during handling of the semiconductor device or semiconductor wafer.

[0033] [Second embodiment] A semiconductor device and a semiconductor wafer according to the present embodiment will be described with reference to Figures 4 and 5. Figure 4 shows a partial wafer of a semiconductor wafer according to the present embodiment. The partial wafer shown in Figure 4 has an X-axis direction that is the direction of the straight line of orientation flat 22. In other words, the orientation on the paper surface corresponds to semiconductor wafer 20 shown in Figure 1(b). This embodiment is an embodiment in which the shape of the trench is changed from that of the above embodiment. Therefore, the configuration of the semiconductor wafer is the same as that of Figure 1(b), and is therefore not shown.

[0034] As shown in FIG. 4, in the semiconductor wafer according to this embodiment, a plurality of trenches 12A having a substantially regular hexagonal shape are densely formed along the scribe lines. The trenches 12A are similar to the trenches 12. A material having a thermal expansion coefficient different from that of SiC is filled inside. When the semiconductor wafer according to this embodiment is scribed along the scribe lines SL and divided into individual pieces, the semiconductor device 10A is obtained. The substantially regular hexagonal trenches 12A or parts of the trenches 12A remain on the peripheral portion 26 (not shown) of the semiconductor device 10A.

[0035] In the semiconductor device 10A and semiconductor wafer according to this embodiment, damage 16 is formed mainly at the corners of trench 12A during the manufacturing process, and this damage 16 stops cracks 18 that have occurred in scribe line SL, just like in the above-mentioned embodiment. In the semiconductor device 10A and semiconductor wafer according to this embodiment, in addition to stopping cracks 18 by damage 16, the surface of trench 12A is more effectively used to stop cracks 18. For this reason, in the semiconductor wafer according to this embodiment, the orientation of trench 12A with respect to orientation flat 22 is taken into consideration.

[0036] Here, the crystal structure of SiC will be briefly described with reference to Fig. 5. Fig. 5(a) shows the (0,0,0,1) plane of the crystal structure C of 4H-SiC adopted in the semiconductor wafer according to the present embodiment, and the symbol A shown in Fig. 5(a) represents an atom (Si or C). 5(a), crystal structure C has three crystal axes, the a1 axis, the a2 axis, and the a3 axis. In the semiconductor wafer according to this embodiment, the direction of orientation flat 22 is the a3 axis. However, the crystal axes aligned with the direction of orientation flat 22 are the a1 axis and the a2 axis.

[0037] Fig. 5(b) is a diagram showing the relationship between the orientation of the trench 12A and the orientation of the crystal structure C. As shown in Fig. 5(b), the trench 12A has six faces S1, S2, S3, S4, S5, and S6. The a1 axis is perpendicular to the faces S1 and S4, the a2 axis is perpendicular to the faces S2 and S5, and the a3 axis is perpendicular to the faces S3 and S6. Here, the face in this embodiment refers to a cross section cut in the depth direction along the straight lines indicated by the symbols S1 to S6.

[0038] Here, SiC crystals have the property of easily cracking along the direction of the crystal axis. Therefore, in this embodiment, as described above, the direction of the crystal axis is set to be perpendicular to each surface in the depth direction of the trench 12A. As a result, even if a crack 18 occurs, it is highly likely that the crack will be stopped by the surface of the trench 12A that exists in the direction of the crack 18. Therefore, according to the semiconductor device 10A and semiconductor wafer of this embodiment, in addition to stopping a crack due to damage, consideration is given to stopping a crack due to the surface of the trench, so that it is possible to more effectively suppress the progression of a crack that occurs in a scribe line when handling the semiconductor device or semiconductor wafer.

[0039] [Third embodiment] A semiconductor device and a semiconductor wafer according to the present embodiment will be described with reference to Figures 6 and 7. Figure 6 shows a partial wafer of a semiconductor wafer according to the present embodiment. The partial wafer shown in Figure 6 has an X-axis direction that is the direction of the straight line of orientation flat 22. In other words, the orientation on the paper surface corresponds to semiconductor wafer 20 shown in Figure 1(b). This embodiment is an embodiment in which the shape of the trench is changed in the first embodiment. Therefore, the configuration of the semiconductor wafer is the same as that of the first embodiment, and is not shown in the figures.

[0040] As shown in FIG. 6, in the semiconductor wafer according to this embodiment, a plurality of diamond-shaped trenches 12B are densely formed along the scribe lines. The trenches 12B are similar to the trenches 12. A material having a thermal expansion coefficient different from that of SiC is filled inside. When the semiconductor wafer according to this embodiment is diced along the scribe lines SL, the semiconductor device 10B is obtained. The diamond-shaped trenches 12B or parts of the trenches 12B remain on the peripheral portion 26 (not shown) of the semiconductor device 10B.

[0041] In the semiconductor device 10B and semiconductor wafer according to this embodiment, damage 16 is formed mainly at the corners of trench 12B during the manufacturing process, and this damage 16 stops crack 18 occurring at scribe line SL, similar to the first embodiment. In the semiconductor device 10B and semiconductor wafer according to this embodiment, in addition to stopping crack 18 by this damage 16, the surface of trench 12B makes it more effective to stop crack 18. For this reason, in the semiconductor wafer according to this embodiment, consideration is given to the orientation of trench 12B with respect to orientation flat 22.

[0042] As shown in FIG. 7, the shape of trench 12B is a rhombus with interior angles of 60° and 120°. The diagonal line connecting the 60° apex angles is the X-axis direction. The basic idea of ​​this embodiment is the same as that of the second embodiment described above, and the orientation of trench 12B with respect to orientation flat 22 is set so that the direction of the crystal axis in which crack 18 is likely to occur is perpendicular to the surface of trench 12B. FIG. 7 shows the relationship between the orientation of trench 12B and the orientation of crystal structure C. As shown in FIG. 7, the direction of the a3 axis of crystal structure C is set to the direction of orientation flat 22 (see also FIG. 1(b)). When trench 12B is disposed as described above, surfaces S1 and S3 are perpendicular to the a1 axis, and surfaces S2 and S4 are perpendicular to the a2 axis. Therefore, for the same reason as in the second embodiment, the progression of crack 18 occurring in scribe line SL can be suppressed.

[0043] 7, the vertices of trenches 12B with 60° apex angles are arranged in the direction of the a3 axis, but no faces are arranged in the direction of the a3 axis. However, since the 60° apex angle is an acute angle, it is considered that damage 16 is more likely to occur. Therefore, in the direction connecting the 60° apex angles of trenches 12B, it is highly likely that crack 18 will be stopped by damage 16.

[0044] As described above in detail, the semiconductor device and semiconductor wafer according to the present embodiment take into consideration not only the stopping of cracks due to damage, but also the stopping of cracks due to the trench faces, making it possible to more effectively suppress cracks that occur in the scribe lines during handling of the semiconductor device or semiconductor wafer.

[0045] In the above embodiments, the semiconductor device and semiconductor wafer using SiC have been described as examples. However, the material constituting the semiconductor device and semiconductor wafer is not limited to SiC, and the technical concept of the present application can be similarly applied to other materials such as Si and GaAs.

[0046] In the above embodiments, the trenches are shaped like a square, a regular hexagon, or a diamond in plan view, but the trenches are not limited to these shapes and may generally be polygonal. Furthermore, the trenches are not limited to polygonal shapes and may be other shapes such as triangular, circular, or elliptical, taking into consideration the susceptibility of damage to occur, the ease of forming the trench, and the like.

[0047] In the above-mentioned embodiments, the trenches of one type of shape are arranged on the scribe line, but the present invention is not limited to this and trenches of multiple types of shapes may be arranged in combination. Taking into consideration ease of arrangement, for example, the above-mentioned regular hexagonal trenches and diamond-shaped trenches may be combined and arranged on the scribe line. Furthermore, even when one type of trench is arranged, the orientation of each trench may be changed as necessary.

[0048] In the above embodiments, the trench 12 is filled with a filling material, but the present invention is not limited to this and may be configured as a hollow structure that is not filled with anything. Even if the trench 12 is a hollow structure, the crack 18 can be stopped by the surface of the trench 12. [Explanation of symbols]

[0049] 10, 10A, 10B Semiconductor device 11 Semiconductor substrate 12, 12A, 12B Trench 16 damage 18, 18A, 18B Crack 20 Semiconductor Wafers 22 Orifura 24 Element Area 26 Periphery a1, a2, a3 axis A atom C crystal structure CL cutting area SL Scribe Line S1, S2, S3, S4, S5, S6 side

Claims

1. a semiconductor substrate made of silicon carbide having elements formed on one surface thereof; a peripheral portion in which the element is not formed, the peripheral portion being disposed in a predetermined region around the semiconductor substrate; a plurality of trenches or portions of trenches formed in the peripheral portion and filled with a material having a thermal expansion coefficient different from that of silicon carbide; Including, The trench is provided in a remaining portion of the peripheral edge portion after cutting and has a groove shape.

2. The thermal expansion coefficient of the material is greater than the thermal expansion coefficient of the silicon carbide. The semiconductor device according to claim 1 .

3. The shape of the semiconductor substrate in a plan view and the shape of the trench in a plan view are rectangular, and the sides of the trench are formed along the sides of the semiconductor substrate.

3. The semiconductor device according to claim 1 or 2.

4. the semiconductor substrate has a crystal structure of 4H—SiC; The semiconductor substrate has a rectangular shape in a plan view, one side of the semiconductor substrate is parallel to a crystal axis of the crystal structure, The trench has a regular hexagonal shape in a plan view, and one diagonal of the trench is perpendicular to the crystal axis.

3. The semiconductor device according to claim 1 or 2.

5. the semiconductor substrate has a crystal structure of 4H—SiC; The semiconductor substrate has a rectangular shape in a plan view, one side of the semiconductor substrate is parallel to a crystal axis of the crystal structure, The trench has a rhombus shape in a plan view having interior angles of 60° and 120°, and a diagonal line connecting the vertices of the 60° interior angles of the trench is parallel to the direction of the crystal axis.

3. The semiconductor device according to claim 1 or 2.

6. a semiconductor substrate made of silicon carbide having a rectangular crystal structure of 4H-SiC on one surface of which an element is formed; a peripheral portion in which the element is not formed, the peripheral portion being disposed in a predetermined region around the semiconductor substrate; a plurality of trenches or portions of trenches formed in the peripheral portion and having a polygonal shape in a plan view, one side of the semiconductor substrate is parallel to a crystal axis of the crystal structure, At least one side of the trench in a plan view is perpendicular to the direction of the crystal axis, The trench is a groove-shaped semiconductor device provided in the remaining portion of the peripheral edge portion after cutting.

7. A semiconductor wafer made of silicon carbide having a plurality of semiconductor devices formed on one surface thereof, a scribe line that divides the semiconductor device; a plurality of trenches formed in the scribe lines and filled with a material having a thermal expansion coefficient different from that of silicon carbide; Including, The trench is a groove-shaped semiconductor wafer provided in a remaining peripheral portion of the semiconductor wafer after cutting in which no elements arranged in a predetermined region around the periphery of the semiconductor wafer are formed.

8. The trench is not formed in a predetermined range from the center of the scribe line in the extension direction. The semiconductor wafer of claim 7.

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