Breaking method and breaking device

Abstract

The present invention breaks a brittle base, that has a diamond layer formed on one surface thereof, with high quality in a short time. Provided is a method for breaking a substrate (S) comprising a plate-shaped base (B) made of a brittle material and a diamond layer (DL) formed on a first main surface (SU1) of the plate-shaped base (B), the method comprising a step in which a scribe line (SL) is formed in the substrate (S), a step in which the substrate (S) having the scribe line (SL) formed therein is placed on a first table (3), and a step in which the portion having the scribe line (SL) of the substrate (S) placed on the first table (3) is pressed to thereby break the substrate (S) along the scribe line (SL). The first table (3) has a Young's modulus of 1-10 GPa.

Description

Breaking method and breaking device

[0001] The present invention relates to a breaking method and breaking device for breaking a brittle substrate having a predetermined layer on one surface.

[0002] Conventionally, known methods for breaking a brittle substrate having a predetermined layer on one surface include a method in which a scribe line is formed on the brittle substrate and the brittle substrate is broken (cut) by pressing the area where the scribe line is formed with a breaking member or the like (see, for example, Patent Document 1), and a method in which a modified layer is formed by irradiating the substrate with laser light and then broken (see, for example, Patent Document 2).

[0003] International Publication No. 2003 / 082542 Japanese Patent Application Laid-Open No. 2005-86175

[0004] Currently, we are investigating breaking brittle substrates (e.g., semiconductor substrates such as Si substrates) that have a diamond layer formed on one surface, but conventional breaking methods have not been able to break these substrates with high quality.

[0005] In conventional breaking methods (e.g., "three-point bending break") that press a substrate with a scribe line formed thereon, the breaking process must be performed twice, which can result in significant peeling of the diamond layer from the substrate. Furthermore, in methods that form a modified layer by irradiating laser light, the diamond layer may be modified, potentially rendering it unusable for its intended application (e.g., a sensor). Furthermore, while a method of cutting the substrate by bringing a grinding wheel rotating at high speed into contact with the substrate can be considered, this method is difficult to perform due to the hardness of the diamond layer.

[0006] An object of the present invention is to break a brittle substrate having a diamond layer formed on one surface with high quality in a short time.

[0007] Below, several aspects will be described as means for solving the problems. These aspects can be combined as desired as necessary. A breaking method according to one aspect of the present invention is a method for breaking a substrate having a plate-shaped substrate made of a brittle material and a diamond layer formed on a first surface of the plate-shaped substrate. The breaking method comprises the following steps: Forming a scribe line on the substrate. Placing the substrate with the scribe line formed on a first table. Breaking the substrate along the scribe line by pressing the portion of the substrate placed on the first table where the scribe line is formed. In the above breaking method, the first table has a Young's modulus of 1 to 10 GPa.

[0008] In the above-described method for breaking a substrate having a plate-shaped substrate made of a brittle material and a diamond layer formed on a first surface of the plate-shaped substrate, the substrate is broken while placed on the first table. As a result, when the substrate is pressed to break it, a large reaction force is applied in the thickness direction of the substrate (the direction from the first table toward the diamond layer) at the portion of the substrate where the scribe line is formed. Furthermore, since the diamond layer can be displaced laterally, a large bending stress is applied to the diamond layer. Since the first table has a Young's modulus of 1 to 10 GPa, the reaction force in the thickness direction of the substrate is optimal, and the bending stress acting on the diamond layer is optimal for cutting the diamond layer. As a result, not only the plate-shaped substrate but also the diamond layer can be broken in a single breaking process.

[0009] If the substrate can be broken in one breaking step with an optimal bending stress, damage to the substrate during the breaking step can be reduced, preventing large separation of the diamond layer from the substrate and achieving high-quality breaking. Furthermore, since a second breaking step is not required, the substrate having a diamond layer on one surface can be broken in a short time.

[0010] In the above breaking method, the scribe line may be formed on a second surface of the plate-shaped substrate opposite to the first surface. The breaking step may also include a step of breaking the substrate by pushing the plate-shaped substrate from the first surface side. This prevents scribe lines from being formed in the diamond layer, allowing the substrate to be broken with high quality. Furthermore, because the plate-shaped substrate side, which is less hard than the diamond layer, is scribed, wear on the scribing wheel can be suppressed, improving its lifespan.

[0011] In the breaking method, the breaking step may include a step of placing a protective film on the diamond layer formed on the first surface, thereby preventing contamination of the diamond layer during breaking.

[0012] In the breaking method described above, the step of forming scribe lines may include a step of fixing the substrate to the second table by air suction. This prevents contamination of the diamond layer during scribing. Also, scribe lines can be formed on multiple substrates at once.

[0013] A breaking device according to another aspect of the present invention is a breaking device for breaking a substrate having a plate-shaped substrate made of a brittle material and a diamond layer formed on a first surface of the plate-shaped substrate. The breaking device comprises a first table and a breaking member. The first table is configured to hold a substrate on which a scribe line has been formed. The breaking member presses the portion of the substrate placed on the first table where the scribe line has been formed, thereby breaking the substrate along the scribe line. In this breaking device, the first table has a Young's modulus of 1 to 10 GPa.

[0014] In the breaking device for breaking a substrate having a plate-shaped substrate made of a brittle material and a diamond layer formed on a first surface of the plate-shaped substrate, the substrate is broken while placed on the first table. As a result, when the substrate is pushed and broken by the breaking member, a large reaction force is applied in the thickness direction of the substrate (the direction from the first table toward the diamond layer) at the portion of the substrate where the scribe line is formed. Furthermore, since the diamond layer can be displaced laterally, a large bending stress is applied to the diamond layer. Since the first table has a Young's modulus of 1 to 10 GPa, the reaction force in the thickness direction of the substrate is optimal, and the bending stress acting on the diamond layer is optimal for cutting the diamond layer. As a result, not only the plate-shaped substrate but also the diamond layer can be broken in a single breaking process.

[0015] If the substrate can be broken in one breaking step with an optimal bending stress, damage to the substrate during the breaking step can be reduced, preventing large separation of the diamond layer from the substrate and achieving high-quality breaking. Furthermore, since a second breaking step is not required, the substrate having a diamond layer on one surface can be broken in a short time.

[0016] Since a plate-shaped substrate made of a brittle material having a diamond layer on one surface thereof can be broken in a single breaking step, the substrate can be broken with high quality in a short time.

[0017] FIG. 1 is a diagram showing the configuration of a breaking device. FIG. 2 is a diagram showing the configuration of a substrate. FIG. 3 is a flowchart showing the substrate breaking operation. FIG. 4 is a diagram showing the formation of a scribe line on the second main surface of the substrate. FIG. 5 is a diagram showing the breaking of a substrate. FIG. 6 is a diagram showing the state of the cut portion of the substrate when the substrate is placed on a first table and broken. FIG. 7 is a diagram showing the state of the cut portion of the substrate when the substrate is broken by three-point bending break.

[0018] 1. First Embodiment (1) Breaking Apparatus The configuration of the breaking apparatus 100 will be described using Figure 1. Figure 1 is a diagram showing the configuration of the breaking apparatus. The breaking apparatus 100 is an apparatus that breaks (cuts) a substrate S to produce predetermined small substrate units. In Figure 1, the left-right direction is the X direction, the normal direction to the paper surface is the Y direction, and the up-down direction is the Z direction (height direction). The breaking apparatus 100 mainly comprises a breaking member 1, a first table 3, and a control unit 5.

[0019] The breaking member 1 is held in the breaking device 100 by a holding member 13 that incorporates a lifting mechanism 11, such as a guide driven by a motor. The breaking member 1 can be raised and lowered in the Z direction relative to the first table 3. The breaking member 1 is, for example, a breaking plate that extends in the Y direction.

[0020] The substrate S to be broken is placed on the first table 3. The first table 3 has a first sub-table 31 and a second sub-table 33. The first sub-table 31 is, for example, a hard plate-like member such as a plate-like glass member. The second sub-table 33 is placed on the first sub-table 31. The substrate S is placed on the second sub-table 33. The second sub-table 33 preferably has a Young's modulus of 1 to 10 GPa, and more preferably has a Young's modulus of 2 to 4 GPa. The thickness of the second sub-table 33 is, for example, approximately 1 to 10 mm.

[0021] The second sub-table 33 can be formed from a resin material having the above Young's modulus, such as an acrylic plate (Young's modulus: 2 to 4 GPa) or a polyethylene terephthalate (PET) plate (Young's modulus: 2 to 3 GPa).

[0022] The second sub-table 33 holds the substrate S together with the dicing frame 6. Specifically, the substrate S is attached to the wafer tape WT so that the wafer tape WT is placed on the main surface (second main surface SU2) of the substrate S on which the diamond layer DL is not formed, a protective film PF is attached to the main surface (first main surface SU1) on which the diamond layer DL is formed, and the dicing frame 6 is fixed to the second sub-table 33 with the end of the wafer tape WT sandwiched between the second sub-table 33 and the dicing frame 6, thereby holding the substrate S between the wafer tape WT and the protective film PF.

[0023] The first table 3 can be moved in the X and Y directions by a moving mechanism 4. This allows the breaking member 1 to contact the substrate S at any position.

[0024] The control unit 5 is a computer system configured with a CPU, storage devices (RAM, ROM, SSD, HDD, etc.), and various interfaces, and controls each part of the break device 100. Some or all of the control functions of the break device 100 performed by the control unit 5 may be realized by executing a program stored in a storage device of the computer system that constitutes the control unit 5, or some or all of the control functions may be realized by hardware that constitutes the computer system that constitutes the control unit 5.

[0025] (2) Substrate The structure of the substrate S to be broken will be described using Figure 2. Figure 2 is a diagram showing the structure of the substrate. The substrate S has a plate-shaped substrate B and a diamond layer DL. The plate-shaped substrate B is a plate-shaped substrate formed of a brittle material such as silicon (Si), either single crystal or polycrystal. Alternatively, a glass substrate, for example, can be used as the plate-shaped substrate B.

[0026] The diamond layer DL is a layer of diamond formed on the first main surface SU1 of the plate-shaped substrate B. The diamond layer DL is formed, for example, from boron-doped diamond, which is doped with boron (B), and is conductive. The substrate S has a total thickness of about 0.1 to 0.8 mm, for example, including the plate-shaped substrate B and the diamond layer DL.

[0027] (3) Substrate Breaking Operation The operation of the breaking device 100 when breaking the above-mentioned substrate S will be described using Figures 3 to 5. Figure 3 is a flowchart showing the substrate breaking operation. Figure 4 is a diagram showing a schematic diagram of how a scribe line is formed on the second main surface of the substrate. Figure 5 is a diagram showing a schematic diagram of how the substrate is broken.

[0028] First, in step S1, as shown in Figure 4, a scribe line SL is formed along the processing line of the substrate S on the second main surface SU2 opposite to the first main surface SU1 (the surface on which the diamond layer DL is formed) of the substrate S. The scribe line SL can be formed, for example, by moving the scribe wheel SW along the processing line while applying a predetermined load to the second main surface SU2. By forming the scribe line on the second main surface SU2 in this way, the scribe line SL is not formed on the diamond layer DL, so the substrate S can be broken with high quality. Furthermore, because the substrate S side, which is lower in hardness than the diamond layer DL, is scribed, wear on the scribe wheel SW can be suppressed, improving its lifespan.

[0029] When forming the scribe line SL, as shown in Figure 4, dust-free paper 8 is laid on the second table 7, and the substrate S is placed on the dust-free paper 8 with its second main surface SU2 facing the scribing wheel SW. The substrate S is then fixed to the second table 7 by air suction. By fixing the substrate S to the second table 7 by air suction in this way, contamination of the diamond layer DL can be suppressed compared to when wafer tape is attached to the diamond layer DL and the substrate S is fixed to the table.

[0030] Furthermore, when fixing by air suction, multiple substrates can be easily fixed to the table, so that scribe lines SL can be formed on multiple substrates S at once.

[0031] After the scribe line SL is formed, in step S2, the substrate S is placed on the first table 3 (second sub-table 33) of the breaking apparatus 100. Specifically, as shown in Figures 1 and 5, a protective film PF is placed on the diamond layer DL (first main surface SU1) side of the substrate S, a wafer tape WT is placed on the second main surface SU2 on which the diamond layer DL is not formed, and the substrate S is placed on the first table 3 so that the first main surface SU1 side of the substrate S (the side on which the diamond layer DL is formed) faces the breaking member 1. Thereafter, the dicing frame 6 is fixed to the first table 3 with the end of the wafer tape WT sandwiched between the first table 3 and the dicing frame 6.

[0032] As described above, by placing a protective film PF on the diamond layer DL formed on the first main surface SU1 at the time of breaking, there is no need to attach a wafer tape or the like to the diamond layer DL, thereby suppressing contamination of the diamond layer DL.

[0033] After the substrate S is placed on the first table 3 of the breaking device 100, in step S3, the breaking member 1 is used to press the portion of the substrate S placed on the first table 3 where the scribe line SL is formed, thereby breaking the substrate S along the scribe line SL. Specifically, the control unit 5 causes the movement mechanism 4 to move the substrate S so that the scribe line SL is positioned below the breaking member 1. Thereafter, the breaking member 1 is moved toward the substrate S and brought into contact with the first main surface SU1 with a predetermined force, thereby extending a vertical crack VC from the scribe line SL in the thickness direction of the plate-shaped substrate B toward the first main surface SU1.

[0034] As described above, the second sub-table 33 on which the substrate S is placed has a Young's modulus of 1 to 10 GPa. By pressing the substrate S while it is placed on the first table 3 (second sub-table 33) which has such an appropriate Young's modulus, a reaction force of an optimum magnitude is applied in the thickness direction of the substrate S (the direction from the first table 3 toward the diamond layer DL), displacing the diamond layer DL laterally, and applying a bending stress of an optimum magnitude for cutting the diamond layer DL. As a result, not only the brittle material plate-like substrate B but also the diamond layer DL can be broken in a single breaking step.

[0035] (4) Example Hereinafter, an example will be described in which the substrate S having the diamond layer DL formed on the first main surface SU1 is broken by performing the above steps S1 to S3 using the breaking device 100 having the above configuration.

[0036] In the examples described below, a silicon substrate was used as the plate-shaped substrate B, and attempts were made to break a substrate S having a diamond layer DL of boron-doped diamond formed on the first main surface SU1 of this plate-shaped substrate B. The thickness of the substrate S was 0.4 mm. The amount of depression of the substrate S by the breaking member 1 was set to 0.10 mm to 0.15 mm.

[0037] As a comparative example, an attempt was made to break the above-mentioned substrate S by three-point bending. In the comparative example, the pushing amount of the breaking member 1 into the substrate S was set to 0.04 mm.

[0038] The substrate S was placed on the first table 3 (second sub-table 33) having a Young's modulus of 1 to 10 GPa, and the substrate S placed on the first table 3 was pressed by the breaking member 1, thereby breaking the substrate S in a single breaking process. Figure 6 shows the state of the cut portion of the substrate S when the substrate S was placed on the first table 3 and broken. As shown in Figure 6, because the substrate S was able to be broken in a single breaking process, almost no large peeling of the diamond layer DL was observed in the cut portion, and the substrate S was able to be broken with high quality. The size of the peeling of the diamond layer DL in this case was about 20 μm on average.

[0039] On the other hand, when the substrate S was broken by three-point bending, the substrate S could not be broken in a single breaking process. Therefore, after the first breaking process, the substrate S was inverted so that the second main surface SU2 side faced the breaking member 1, and the second main surface SU2 side was pressed with the breaking member 1 to break the substrate S. Figure 7 shows the state of the cut portion of the substrate S when the substrate S was broken by three-point bending. As shown in Figure 7, after two breaking processes were performed on the substrate S, large peeling of the diamond layer DL was observed in the cut portion, and the quality of the cut portion of the substrate S was low. In this case, the size of the peeling of the diamond layer DL averaged about 80 μm.

[0040] The reason why the substrate S could not be broken in a single breaking step in the case of three-point bending break is thought to be that, in three-point bending break, the portion of the second main surface SU2 of the substrate S where the scribe line SL is formed is not supported by a table or the like and is disposed in space. Specifically, if the portion of the second main surface SU2 where the scribe line SL is formed is disposed in space, when the first main surface SU1 side of the substrate S is pressed by the breaking member 1, the substrate S is displaced significantly in the vertical direction, and the portion of the second main surface SU2 where the scribe line SL is formed is displaced significantly in the horizontal direction, resulting in a large bending stress acting on the portion where the scribe line SL is formed. On the other hand, because the second main surface SU2 is displaced excessively in the horizontal direction, the diamond layer DL formed on the first main surface SU1 is only displaced slightly in the horizontal direction, and a bending stress large enough to cut the diamond layer DL is not exerted on the diamond layer DL. For this reason, a second breaking step in which the substrate S is pressed from the second main surface SU2 side is required to apply sufficient bending stress to the diamond layer DL.

[0041] In this way, when breaking the substrate S using three-point bending breaking, two breaking processes were required, and it is thought that, for example, the position at which the substrate S is pressed may differ between the first and second breaking processes, causing greater damage to the substrate S due to breaking, resulting in many large peelings of the diamond layer DL from the substrate S and lowering the quality of the cut portion.

[0042] On the other hand, in the breaking apparatus 100, breaking of the substrate S is performed with the substrate S placed on the first table 3. That is, breaking of the substrate S is performed with the portion of the second main surface SU2 of the substrate S where the scribe line SL is formed also supported by the first table 3. As a result, when the first main surface SU1 of the substrate S is pressed and broken by the breaking member 1, the vertical displacement of the substrate S at the portion where the scribe line SL is formed is smaller than in three-point bending breaking, and a large reaction force is applied in the thickness direction of the substrate S (the direction from the first table 3 toward the diamond layer DL). Furthermore, because the second main surface SU2 is not displaced excessively, the diamond layer DL formed on the first main surface SU1 can be displaced significantly laterally, so a large bending stress is applied to the diamond layer DL. Since the first table 3 has a Young's modulus of 1 to 10 GPa, the reaction force in the thickness direction of the substrate S is optimal, and the bending stress acting on the diamond layer DL is optimal for cutting the diamond layer. As a result, not only the plate-shaped substrate B but also the diamond layer DL can be broken in one breaking step.

[0043] As described above, if the substrate S can be broken in a single breaking step using an optimal amount of bending stress, damage to the substrate S during the breaking step can be reduced, thereby suppressing large peeling of the diamond layer DL from the substrate S and achieving high-quality breaking. Furthermore, since a second breaking step is not required, the substrate S can be broken in a short time.

[0044] 2. Other Embodiments While several embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and various modifications are possible without departing from the spirit and scope of the invention. In particular, the several embodiments and modifications described in this specification can be arbitrarily combined as needed. (A) A conductive layer made of a conductive material such as a metal may be formed on the second main surface SU2 of the substrate S. This conductive layer may be a film of a conductive material or may be formed from a conductive tape. When a conductive layer is formed on the second main surface SU2, the cutting edge of the scribe wheel SW is made acuter, and the load when pressing the cutting edge of the scribe wheel SW against the second main surface SU2 is also increased, compared to when a scribe line SL is formed on a second main surface SU2 that does not have a conductive layer.

[0045] (B) The entire first table 3 may be made of a material (for example, a resin material) having a Young's modulus of 1 to 10 GPa.

[0046] (C) The first table 3 (second sub-table 33) may be made of a material other than a resin material having a Young's modulus of 1 to 10 GPa.

[0047] 3. Features of the Embodiments The above embodiments can also be described as follows. (1) A breaking method for breaking a substrate (e.g., substrate S) having a plate-shaped substrate (e.g., plate-shaped substrate B) made of a brittle material and a diamond layer (e.g., diamond layer DL) formed on a first surface (e.g., first main surface SU1) of the plate-shaped substrate includes the following steps: ◎ A step of forming a scribe line (e.g., scribe line SL) on the substrate (e.g., step S1). ◎ A step of placing the substrate with the scribe line formed on a first table (e.g., first table 3) (e.g., step S2). ◎ A step of pressing the portion of the substrate placed on the first table where the scribe line is formed, thereby breaking the substrate along the scribe line (e.g., step S3). In the above breaking method, the first table has a Young's modulus of 1 to 10 GPa.

[0048] In the above-described method for breaking a substrate having a plate-shaped substrate made of a brittle material and a diamond layer formed on a first surface of the plate-shaped substrate, the substrate is broken while placed on the first table. As a result, when the substrate is pressed to break it, a large reaction force is applied in the thickness direction of the substrate (the direction from the first table toward the diamond layer) at the portion of the substrate where the scribe line is formed. Furthermore, since the diamond layer can be displaced laterally, a large bending stress is applied to the diamond layer. Since the first table has a Young's modulus of 1 to 10 GPa, the reaction force in the thickness direction of the substrate is optimal, and the bending stress acting on the diamond layer is optimal for cutting the diamond layer. As a result, not only the plate-shaped substrate but also the diamond layer can be broken in a single breaking process.

[0049] If the substrate can be broken in one breaking step with an optimal bending stress, damage to the substrate during the breaking step can be reduced, preventing large separation of the diamond layer from the substrate and achieving high-quality breaking. Furthermore, since a second breaking step is not required, the substrate having a diamond layer on one surface can be broken in a short time.

[0050] (2) In the breaking method of (1) above, the scribe line may be formed on a second surface of the plate-shaped substrate opposite the first surface. The breaking step may also include a step of breaking the substrate by pushing the plate-shaped substrate from the first surface side. This prevents scribe lines from being formed in the diamond layer, allowing the substrate to be broken with high quality. Furthermore, because the plate-shaped substrate side, which is less hard than the diamond layer, is scribed, wear on the scribing wheel can be suppressed, improving its lifespan.

[0051] (3) In the breaking method of (2) above, the breaking step may include a step of placing a protective film (e.g., protective film PF) on the diamond layer formed on the first surface, thereby preventing contamination of the diamond layer during breaking.

[0052] (4) In any of the breaking methods (1) to (3) above, the step of forming a scribe line may include a step of fixing the substrate to the second table (e.g., second table 7) by air suction. This prevents contamination of the diamond layer during scribing. Also, scribe lines can be formed on multiple substrates at once.

[0053] (5) A breaking device (e.g., breaking device 100) for breaking a substrate having a plate-shaped substrate made of a brittle material and a diamond layer formed on a first surface of the plate-shaped substrate includes a first table and a breaking member (e.g., breaking member 1). The first table is configured to hold a substrate on which a scribe line has been formed. The breaking member presses the portion of the substrate placed on the first table where the scribe line has been formed, thereby breaking the substrate along the scribe line. In this breaking device, the first table has a Young's modulus of 1 to 10 GPa.

[0054] In the breaking device for breaking a substrate having a plate-shaped substrate made of a brittle material and a diamond layer formed on a first surface of the plate-shaped substrate, the substrate is broken while placed on the first table. As a result, when the substrate is pushed and broken by the breaking member, a large reaction force is applied in the thickness direction of the substrate (the direction from the first table toward the diamond layer) at the portion of the substrate where the scribe line is formed. Furthermore, since the diamond layer can be displaced laterally, a large bending stress is applied to the diamond layer. Since the first table has a Young's modulus of 1 to 10 GPa, the reaction force in the thickness direction of the substrate is optimal, and the bending stress acting on the diamond layer is optimal for cutting the diamond layer. As a result, not only the plate-shaped substrate but also the diamond layer can be broken in a single breaking process.

[0055] If the substrate can be broken in one breaking step with an optimal bending stress, damage to the substrate during the breaking step can be reduced, preventing large separation of the diamond layer from the substrate and achieving high-quality breaking. Furthermore, since a second breaking step is not required, the substrate having a diamond layer on one surface can be broken in a short time.

[0056] The present invention is widely applicable to an apparatus and method for breaking a brittle substrate having a diamond layer on one surface.

[0057] 100: Breaking device 1: Breaking member 11: Elevating mechanism 13: Holding member 3: First table 31: First sub-table 33: Second sub-table SW: Scribe wheel 4: Moving mechanism 5: Control unit 6: Dicing frame 7: Second table 8: Dust-free paper S: Substrate SU1: First main surface SU2: Second main surface B: Plate-shaped substrate DL: Diamond layer PF: Protective film WT: Wafer tape

Claims

1. A method for breaking a substrate having a plate-shaped substrate made of a brittle material and a diamond layer formed on a first surface of the plate-shaped substrate, the method comprising the steps of: forming a scribe line on the substrate; placing the substrate with the scribe line formed on a first table; and breaking the substrate along the scribe line by pressing the portion of the substrate placed on the first table where the scribe line is formed, wherein the first table has a Young's modulus of 1 to 10 GPa.

2. The breaking method according to claim 1, wherein the scribe line is formed on a second surface of the plate-like substrate opposite the first surface, and the breaking step includes a step of pushing the plate-like substrate from the first surface side to break the substrate.

3. The breaking method of claim 2, wherein the breaking step includes the step of placing a protective film on the diamond layer formed on the first surface.

4. The breaking method according to claim 1, wherein the step of forming the scribe line includes a step of fixing the substrate to a second table by air suction.

5. A breaking device for breaking a substrate having a plate-like substrate made of a brittle material and a diamond layer formed on a first surface of the plate-like substrate, comprising: a first table for placing the substrate having a scribe line formed thereon; and a breaking member for breaking the substrate along the scribe line by pressing the portion of the substrate placed on the first table where the scribe line is formed, wherein the first table has a Young's modulus of 1 to 10 GPa.