TW201711820A - Method for cutting brittle substrate - Google Patents

Abstract

A cutting edge (51) having a protruding portion (PP) and a side portion (PS) that extends from the protruding portion (PP) and has a convex shape is caused to slide on one surface (SF1) of a brittle substrate (4) in a direction from the protruding portion (PP) toward the side portion (PS), whereby a trench line (TL) having a groove shape is formed by the generation of plastic deformation on the one surface (SF1). A crack line (CL) is formed by extending a crack of the brittle substrate (4) along at least a part of the trench line (TL). The brittle substrate (4) is cut along the crack line (CL). The step for forming the trench line (TL) is carried out such that the direction in which the crack line (CL) extends along the trench line (TL) in the step for forming the crack line (CL) is the same as the direction in which the trench line (TL) is formed.

Description

Fragmentation method of brittle substrate

The present invention relates to a method of breaking a brittle substrate.

In the manufacture of electrical equipment such as a flat display panel or a solar cell panel, it is often necessary to separate a brittle substrate such as a glass substrate. First, a scribe line is formed on the substrate, and then the substrate is separated along the scribe line. The scribing system can be formed by machining a substrate using a milling cutter. By sliding or rolling the milling cutter on the substrate, grooves are formed by plastic deformation on the substrate, and vertical cracks are formed below the grooves. Thereafter, stress imparting is referred to as a fracture step. The crack is completely traveled in the thickness direction by the breaking step, thereby breaking the substrate. The step of breaking the substrate is mostly performed immediately after the step of forming the scribe line on the substrate. However, a step of processing the substrate between the step of forming the scribe line and the rupturing step is also proposed. The step of processing the substrate is, for example, a step of providing a plurality of members on the substrate. For example, according to the technique of the international patent publication No. 2002/104078, in the manufacturing method of an organic EL (Electroluminescence) display, a scribe line is formed on a glass substrate in each region of each organic EL display before the sealing cover is mounted. . Therefore, it is possible to avoid contact between the sealing cover which is a problem when the scribing is formed on the glass substrate after the sealing cover is provided, and the glass milling cutter. Further, for example, according to the technique of the international patent publication No. 2003/006391, in the method of manufacturing a liquid crystal display panel, two glass substrates are bonded together after forming a scribe line. Thereby, two brittle substrates can be simultaneously fractured in one breaking step. [Prior Art Document] [Patent Document] [Patent Document 1] International Patent Publication No. 2002/104078 [Patent Document 2] International Patent Publication No. 2003/006391

[Problems to be Solved by the Invention] According to the above prior art, the processing of the brittle substrate is performed after the scribing is formed, and thereafter the breaking step is performed by stress imparting. It means that vertical cracks already exist when processing a brittle substrate. Since the further extension of the vertical crack in the thickness direction is unintentionally generated during processing, it is possible to cause a brittle substrate which should be integrated in the breaking process. Further, in the case where the substrate processing step is not performed between the step of forming the scribe line and the step of structuring the substrate, it is usually necessary to transport or store the substrate after the step of forming the scribe line and before the step of rupturing the substrate, so that it is also possible The substrate is unintentionally broken at this time. Therefore, it is extremely useful to specify the position of the brittle substrate by dividing the line which does not accompany the vertical crack (in other words, the line "without the crack-free state"). Further, when there is no need to worry about the unexpected breaking as described above, the position of the brittle substrate can be specified by the line without the vertical crack, so that the blade is pressed against the brittle substrate even in the forming step of the wire. A further reduction in the load is also sufficient. The reduction in tip load is useful in reducing wear on the tip or damage to the surface of the brittle substrate. However, the technique of forming a line which can specify the position of the breaking brittle substrate without accompanying the vertical crack using the sliding of the blade tip has not been sufficiently studied so far. Of course, the line that is usually not accompanied by vertical cracks is only considered to be a simple defective line due to insufficient load on the tip. The present invention has been made in order to solve the above problems, and an object of the invention is to provide a method for breaking a brittle substrate which can define a position of a brittle substrate by a line which does not accompany a vertical crack. [Technical means for solving the problem] The breaking method of the brittle substrate according to one aspect of the present invention has the following steps a) to c). a) by causing a blade tip having a protrusion portion and a side portion extending from the protrusion portion and having a convex shape to slide on one side of the brittle substrate from the protrusion portion toward the side portion, plastic deformation is formed on one surface, and is formed A grooved line having a groove shape. The groove line is formed in such a manner that a state in which the brittle substrate is continuously connected in a direction crossing the groove line, that is, a crack-free state, is formed below the groove line. b) forming a crack line by stretching a crack of the brittle substrate along at least a portion of the trench line. The continuous connection of the brittle substrate to the direction intersecting the groove line is broken by the crack line below the groove line. c) Breaking the brittle substrate along the crack line. Step a) is carried out in step b) in such a manner that the direction in which the crack line extends along the groove line is the same as the direction in which the groove line is formed. The breaking method of the brittle substrate according to another aspect of the present invention has the following steps a) to c). a) by causing a blade tip having a protrusion portion and a side portion extending from the protrusion portion and having a convex shape to slide on one side of the brittle substrate from the side portion toward the protrusion portion, plastic deformation is formed on one surface, and is formed A grooved line having a groove shape. The groove line is formed in such a manner that a state in which the brittle substrate is continuously connected in a direction crossing the groove line, that is, a crack-free state, is formed below the groove line. b) forming a crack line by stretching a crack of the brittle substrate along at least a portion of the trench line. The continuous connection of the brittle substrate to the direction intersecting the groove line is broken by the crack line below the groove line. c) Breaking the brittle substrate along the crack line. Step a) is carried out in step b) in such a manner that the direction in which the crack line extends along the groove line is opposite to the direction in which the groove line is formed. [Effect of the Invention] According to the present invention, as a line defining a position at which the brittle substrate is cut, a groove line having no crack below it is formed. The crack line used as a direct trigger for breaking is formed by forming a groove line and causing the crack to extend along it. Thereby, the position of the brittle substrate can be determined by dividing the line without the vertical crack.

Hereinafter, embodiments of the present invention will be described based on the drawings. In the following drawings, the same or corresponding components are denoted by the same reference numerals, and the description thereof will not be repeated. (Embodiment 1) (Configuration of Cutting Apparatus) First, the configuration of the cutting tool 50 used in the groove line forming step in the method of dividing the glass substrate 4 (brittle substrate) of the present embodiment will be described with reference to Fig. 1 . The cutting tool 50 has a blade edge 51 and a shank 52. The blade tip 51 is held by being fixed to the shank 52 as its holder. The blade tip 51 is provided with a top surface SD1 (first surface) and a plurality of surfaces surrounding the top surface SD1. The plurality of faces include a side surface SD2 (second surface) and a side surface SD3 (third surface). The top surface SD1, the side surfaces SD2, and the SD3 (the first to third surfaces) are oriented in mutually different directions and adjacent to each other. The blade tip 51 has a vertex at which the top surface SD1, the side surfaces SD2, and SD3 meet, and the apex constitutes the protrusion PP of the blade edge 51. Further, the side faces SD2 and SD3 form a ridge line constituting the side portion PS of the blade edge 51. The side portion PS extends linearly from the protrusion portion PP. Moreover, since the side portion PS is a ridge line as described above, it has a convex shape extending linearly. The tip 51 is preferably a diamond cutter head. That is, the blade tip 51 is preferably made of diamond in terms of the reduction in hardness and surface roughness. More preferably, the tip 51 is made of single crystal diamond. Further preferably, from the viewpoint of crystallography, the top surface SD1 is a {001} plane, and the side surfaces SD2 and SD3 are each a {111} plane. In this case, although the side surface SD2 and the side surface SD3 have different orientations, they are crystallographically equivalent to each other. Further, a non-single crystal diamond may be used, and for example, a polycrystalline diamond synthesized by a CVD (Chemical Vapor Deposition) method may also be used. Alternatively, it is also possible to use a sintered diamond in which polycrystalline diamond particles sintered without a combination of iron group elements and the like are bonded by a binder such as an iron group element from particulate graphite or non-graphite carbon. The shank 52 extends along the axial direction AX. The blade tip 51 is preferably attached to the shank 52 so as to be substantially along the axial direction AX in the normal direction of the top surface SD1. (Method of Breaking Glass Substrate) In the present embodiment, a method of dividing the glass substrate 4 including the step of sliding the blade edge 51 (FIG. 1) on the upper surface SF1 of the glass substrate 4 in the direction DA (FIG. 2) )Be explained. The glass substrate 4 to be separated has an upper surface SF1 (one surface) and a surface SF2 (the other surface) opposite thereto. Referring to Fig. 3, the edge surrounding the upper surface SF1 includes sides ED1 (first side) and side ED2 (second side) facing each other. In the example shown in Fig. 3, the edges are rectangular. Therefore, the sides ED1 and ED2 are sides parallel to each other. Moreover, in the example shown in FIG. 3, the sides ED1 and ED2 are short sides of a rectangle. Further, the glass substrate 4 has a thickness direction DT perpendicular to the upper surface SF1. Referring to FIGS. 2 and 3, a groove line TL is formed in step S30. Specifically, the following steps are performed. First, the protrusion PP and the side portion PS of the blade edge 51 are pressed against the position N1 on the upper surface SF1. Details of the position N1 will be described below. Referring to FIG. 1(A), the protrusion PP of the blade edge 51 is disposed between the side ED1 and the side portion PS on the upper surface SF1 of the glass substrate 4, and the side of the blade edge 51 is placed. The PS is disposed between the protrusion portion PP and the side ED2. Next, the pressed blade tip 51 is slid on the upper surface SF1 of the glass substrate 4 (see an arrow in FIG. 3). The blade edge 51 (FIG. 1) slides on the upper surface SF1 in the direction DA from the protrusion PP toward the side portion PS. In other words, the blade edge 51 is slid in a direction DA projected from the projection portion PP toward the side portion PS on the upper surface SF1. The direction DA is generally projected in a direction in which the extending direction of the side portion PS near the protrusion PP is projected on the upper surface SF1. Plastic deformation occurs on the upper surface SF1 by the sliding. Thereby, a groove line TL having a groove shape (five lines in the drawing) is formed on the upper surface SF1. In this manner, the groove line TL is generated by plastic deformation of the glass substrate 4, and the plastic deformation is sufficiently formed without lowering the load on the surface of the glass substrate, but the glass substrate 4 may be slightly cut. However, since such cutting produces undesired fine fragments, it is preferably not produced. The formation of the trench line TL is performed between the position N1 and the position N3. Position N2 is located between positions N1 and N3. Therefore, the groove line TL is formed between the positions N1 and N2 and between the positions N2 and N3. The positions N1 and N3 may be located at a position spaced apart from the edge of the upper surface SF1 of the glass substrate 4 as shown in FIG. 3, or one or both of them may be located at the edge of the upper surface SF1. The groove line TL to be formed is spaced apart from the edge of the glass substrate 4 in the former case, and is in contact with the edge of the glass substrate 4 in the latter case. In the positions N1 and N2, the position N1 is closer to the side ED1; and in the positions N1 and N2, the position N2 is closer to the side ED2. Furthermore, in the example shown in FIG. 3, the position N1 is closer to the side ED1 in the sides ED1 and ED2, and the position N2 is closer to the side ED2 in the sides ED1 and ED2, but the positions N1 and N2 may be located at both. Approaching the position of either of the edges ED1 or ED2. In the case where the groove line TL is formed, in the present embodiment, the blade edge 51 is displaced from the position N1 to the position N2, and further displaced from the position N2 to the position N3. That is, referring to Fig. 1, the blade edge 51 is displaced in the direction DA from the side ED1 toward the side ED2. The direction DA corresponds to a direction in which the axial direction AX extending from the blade edge 51 is projected on the upper surface SF1. In this case, the blade tip 51 is dragged on the upper surface SF1 by the shank 52. Referring to FIG. 4, the step of forming the trench line TL may be performed as follows: obtained under the trench line TL, the glass substrate 4 is crossed in a direction crossing the extending direction of the trench line TL (the lateral direction of FIG. 3(B)) The state of continuous connection is the state of no crack. In the crack-free state, although the groove line TL is formed by plastic deformation, a crack along it is not formed. Therefore, even if a force such as a bending moment is simply applied to the glass substrate 4 as in the previous breaking step, the breaking along the groove line TL is not easily caused. Therefore, the breaking step along the groove line TL is not performed in the state without the crack line. In order to obtain a crack-free state, the load applied to the cutting edge 51 is adjusted to be small to the extent that cracks are not generated at the time of scribing, and plastic deformation is generated as in the state of creating an internal stress which causes the crack to be generated in the subsequent step. degree. The above crack-free state can be maintained for a desired period of time. In order to maintain the crack-free state, it is only necessary to avoid the operation of applying excessive stress to the glass substrate 4 in the trench line TL, for example, to avoid the application of a large external stress which may cause damage to the substrate or a heating accompanied by a large temperature change. can. During this period, the glass substrate 4 can be transferred or stored or processed. The processing of the glass substrate 4 may be, for example, a step of providing a member (not shown) on the glass substrate 4. Referring to FIG. 5, in step S50 (FIG. 2) subsequent to step S30 (FIG. 2), the crack of the glass substrate 4 extends along at least a portion of the groove line TL in the thickness direction DT. In Fig. 5, the crack of the glass substrate 4 is stretched along a portion between the position N2 and the position N3 in the groove line TL (Fig. 3) formed. Thereby, the crack line CL is formed. In the present embodiment, the formation of the crack line CL is started by forming the auxiliary line AL which intersects the groove line TL at the position N2. The auxiliary line AL may be a general scribe line accompanying the crack in the thickness direction DT, and is a strainer that releases the internal stress near the groove line TL. The method of forming the auxiliary line AL is not particularly limited, but as shown in FIG. 5, the edge of the upper surface SF1 may be formed as a base point. Referring to Fig. 6, by the crack line CL, below the groove line TL, the glass substrate 4 is continuously disconnected in the direction DC which intersects with the extending direction of the groove line TL (the lateral direction of Fig. 5). Here, the term "continuously connected", in other words, is not connected by a crack. Further, in a state in which the glass substrate 4 is continuously connected and disconnected as described above, portions of the glass substrate 4 may be in contact with each other via a crack of the crack line CL. Further, just below the groove line TL, a slight residual may be continuously connected. Further, in the present embodiment, the direction in which the crack line CL (Fig. 5) extends along the groove line TL (Fig. 3) (the dotted arrow in Fig. 5) is set to the direction in which the groove line TL is formed (Fig. 3) The solid arrow is the same. In order to select the direction in which the crack line CL is stretched as described above, the method of forming the groove line TL may be appropriately selected. According to the research of the present inventors, when the groove line TL is formed by sliding in the direction DA of the blade edge 51 (FIG. 1) as in the present embodiment, the axial direction AX of the blade edge 51 is relative to the glass substrate. 4 The upper surface SF1 is nearly vertical, and the direction in which the crack line CL extends is the same as the direction in which the groove line TL extends. Further, in the case where the groove line TL is formed by the sliding of the blade edge 51 (FIG. 1) in the direction DA as in the present embodiment, the axial direction AX is opposite to the above from the upper surface SF1 of the glass substrate 4. When the normal line is largely inclined, the direction in which the crack line CL extends is opposite to the direction in which the groove line TL extends. If the axial direction AX is the intermediate angle, the direction of extension of the crack line CL is unstable and difficult to predict. Therefore, in order to make the extending direction of the crack line CL more surely the same as the direction in which the groove line TL is formed, the blade edge 51 is adjusted so that the angle of the axial direction AX (FIG. 1) is closer to the vertical with respect to the upper surface SF1. The posture can be. In other words, by increasing the angle AG1 between the upper surface SF1 and the side surface SD3 and decreasing the angle AG2 between the upper surface SF1 and the top surface SD1, the extension direction of the crack line CL can be more surely set to the groove line. The TL stretches in the same direction. When the posture of the blade edge 51 (FIG. 1) is adjusted as described above, the angle AG1 is increased and the angle AG2 is decreased. According to the first experiment using the blade tip 51 having an angle of 158° between the top surface SD1 and the side portion PS, if the angle AG1=5° and the angle AG2=17°, the direction of the crack line CL and the groove line are extended. The extension of TL is reversed. By adjusting the axial direction AX, if the angle AG1 = angle AG2 = 11°, the direction in which the crack line CL extends is the same as the direction in which the groove line TL extends. According to the second experiment using the blade tip 51 having an angle of 165° between the top surface SD1 and the side portion PS, if the angle AG1=5° and the angle AG2=10°, the direction of the crack line CL and the groove line are extended. The extension of TL is reversed. By adjusting the axial direction AX, if the angle AG1 = 7° and the angle AG2 = 8°, the direction in which the crack line CL extends is the same as the direction in which the groove line TL extends. Further, since the projection PP of the blade edge 51 is desirably sharp to some extent, the angle between the top surface SD1 and the side portion PS is preferably about 160° or less. Under such conditions, in order to make the extending direction of the crack line CL the same as the extending direction of the groove line TL, the angle AG2 is preferably the angle AG1. When the extending direction of the crack line CL is selected as described above, the crack of the glass substrate 4 is in the thickness direction DT along the groove line TL from the position N2 to the position N3 (refer to the dotted arrow in FIG. 5) (FIG. 6) )stretch. Further, it is difficult to form the crack line CL from the position N2 toward the position N1 as compared with the direction from the position N2 to the position N3. That is, the ease of stretching of the crack line CL has a direction dependency. Therefore, a phenomenon in which the crack line CL is formed between the positions N2 and N3 and is not formed between the positions N2 and N1 may occur. In the present embodiment, the glass substrate 4 is separated between the positions N2 and N3, and the glass substrate 4 is not separated between the positions N2 and N1. Therefore, it is necessary to form the crack line CL between the position N2 and the position N3, and on the other hand, the difficulty in forming the crack line CL between the positions N2 and N1 is not a problem. Next, in step S60 (FIG. 2), the glass substrate 4 is separated along the crack line CL. That is, a so-called breaking step is performed. The breaking step can be performed, for example, by applying an external force to the glass substrate 4. For example, the stress applying member is pressed against the lower surface SF2 toward the crack line CL (FIG. 6) on the upper surface SF1 of the glass substrate 4, and stress is applied to the glass substrate 4 so as to cut the crack line CL. Further, when the crack line CL is completely advanced in the thickness direction DT at the time of its formation, the formation of the crack line CL and the breaking glass substrate 4 can be simultaneously produced. The division of the glass substrate 4 is performed by the above. Furthermore, the above-described step of forming the crack line CL is substantially different from the so-called breaking step. The breaking step is such that the crack that has been formed is further stretched in the thickness direction to completely separate the substrate. On the other hand, the step of forming the crack line CL is to change the state from the crack-free state obtained by forming the groove line TL to the state having the crack. This change is believed to be caused by the internal stresses that open the crack-free state. Considering the plastic deformation at the time of forming the groove line TL and the magnitude or directivity of the internal stress generated by forming the groove line TL, when the rotary blade is used for rolling, the blade tip is used as in the present embodiment. In the case of sliding, when the blade is used for sliding, cracks are likely to occur under a wide scribing condition. Further, the internal stress is required to open the internal stress as a trigger. In the present embodiment, the formation of the auxiliary line AL functions as such a trigger. Further, the above description has been made on the case where the upper surface SF1 is flat, but the upper surface is bendable. Further, the case where the groove line TL is linear is described, but the groove line may have a curved shape. Further, although the case where the glass substrate 4 is used as the brittle substrate has been described, the brittle substrate may be made of a brittle material other than glass, and may be made of, for example, ceramics, tantalum, compound semiconductor, sapphire, or quartz. (Effects) According to the present embodiment, as a line defining the position at which the glass substrate 4 is cut, a groove line TL (Fig. 4) having no crack below it is formed. The crack line CL (Fig. 6) used as a direct trigger for the breaking is formed by forming the groove line TL and causing the crack to extend along it. Thereby, the position of the glass substrate 4 can be divided by the groove line TL which is not accompanied by the vertical crack. As described above, the groove line TL which is a line which does not accompany the vertical crack is easier to form than the normal scribe line which is accompanied by the vertical crack, even if the load of pressing the blade edge 51 against the glass substrate 4 is small. Reducing the load of the blade tip 51 helps to reduce the wear of the blade tip 51 or the damage of the upper surface SF1 of the glass substrate 4. Further, when the blade edge 51 is slid toward the direction DA (FIG. 1) as in the present embodiment, partial wear of the blade edge 51 is less likely to occur than when the blade edge 51 is slid toward the direction DB. Thereby, the life of the cutting edge 51 is extended. Further, after the groove line TL is formed and the crack line CL is formed before the glass substrate 4 (FIG. 3), even if the position of the glass substrate 4 is to be separated by the groove line TL, since the crack line CL has not been formed, it is difficult. The state of the break. By using this state, even if the position at which the glass substrate 4 is to be separated is predetermined, the glass substrate 4 can be prevented from being unintentionally broken before the time point at which the glass substrate 4 should be broken. For example, the glass substrate 4 can be prevented from being unintentionally broken during the conveyance. Further, it is possible to prevent the glass substrate 4 from being unintentionally broken during the processing of the glass substrate 4. Further, in the present embodiment different from the second embodiment described below, the auxiliary line AL (Fig. 5) has not been formed at the time point (Fig. 3) at which the groove line TL has been formed. Therefore, it is possible to maintain the crack-free state more stably without being affected by the auxiliary line AL. (First Modification) Referring to Fig. 7, the first variation is about the case where the auxiliary line AL and the groove line TL intersect at the position N2, and the triggering of the crack line CL (Fig. 5) is insufficient. Referring to Fig. 8, by applying an external force such as a bending moment to the glass substrate 4, the crack extends in the thickness direction DT along the auxiliary line AL, and as a result, the glass substrate 4 is separated. Taking this as a trigger, the formation of the crack line CL is started. According to the present modification, the crack line CL can be formed more surely from the groove line TL. Further, in the present modification, the strain of the internal stress near the groove line TL is released by separating the glass substrate 4, thereby starting to form the crack line CL. Therefore, the auxiliary line AL itself may be the crack line CL formed by applying stress to the groove line TL. Further, in Fig. 7, the auxiliary line AL is formed on the upper surface SF1 of the glass substrate 4, but may be formed on the lower surface SF2. In this case, the auxiliary line AL and the groove line TL are arranged in a plan view and intersect each other at the position N2, but are not in direct contact with each other. (Second Modification) Referring to Fig. 9, in the second modification, in step S30 (Fig. 2), when the groove line TL is formed, the position N2 is at a position N2 from the position N3 of the upper surface SF1 of the glass substrate 4. Press the tip 51 with a greater force. Specifically, the position N4 is set as the position between the positions N3 and N2, and the load of the blade edge 51 is lowered at the time point when the groove line TL forms the arrival position N4. In other words, the load of the cutting edge 51 is increased between the positions N1 and N4 at the beginning end of the groove line TL as compared with the position N3. Thereby, the load other than the start end portion is alleviated, and the crack line CL can be more easily formed from the position N2. <Second Embodiment> Hereinafter, a method of dividing the glass substrate 4 of the present embodiment will be described with reference to Figs. 10 to 12 . Referring to Fig. 10, in the present embodiment, unlike the first embodiment, the auxiliary line AL is formed before the formation of the groove line TL. The method of forming the auxiliary line AL itself is the same as that of Fig. 5 (Embodiment 1). Referring to Fig. 11, next, in step S20 (Fig. 2), the blade edge 51 is pressed against the upper surface SF1, and then, in step S30 (Fig. 2), the groove line TL is formed. The method of forming the groove line TL itself is the same as that of Fig. 3 (Embodiment 1). The auxiliary line AL and the groove line TL cross each other at the position N2. Referring to Fig. 12, next, the glass substrate 4 is separated along the auxiliary line AL by applying a usual breaking step of generating a force such as a bending moment to the glass substrate 4. As a result, in step S50 (FIG. 2), the same crack line CL as in the first embodiment is formed (in the figure, a broken line arrow is referred to). Further, in FIG. 10, the auxiliary line AL is formed on the upper surface SF1 of the glass substrate 4, but the auxiliary line AL for separating the glass substrate 4 may be formed on the lower surface SF2 of the glass substrate 4. In this case, the auxiliary line AL and the groove line TL cross each other at the position N2 in a planar layout, but are not in direct contact with each other. In addition, the configuration other than the above is substantially the same as the configuration of the above-described first embodiment. Referring to Fig. 13, a modification will be described next. In the present modification, in step S30 (FIG. 2), when the groove line TL is formed, the blade edge 51 is pressed with a greater force at the position N2 than the position N3 of the upper surface SF1 of the glass substrate 4. Specifically, the position N4 is taken as the position between the positions N3 and N2, and the load of the blade edge 51 is lowered at the time point when the groove line TL is formed to reach the position N4. In other words, the load of the cutting edge 51 is increased between the positions N1 and N4 at the beginning end of the groove line TL as compared with the position N3. Thereby, the load other than the start end portion is alleviated, and the crack line CL can be more easily formed from the position N2. <Third Embodiment> In the present embodiment, unlike the first and second embodiments, the groove line TL is formed on the upper surface SF1 of the glass substrate 4 by the blade edge 51 (Fig. 1) instead of the direction DA in the direction DB. Formed by sliding. Specifically, the following steps are performed. Referring to Fig. 14, first, the protrusion portion PP and the side portion PS of the blade edge 51 are pressed at the upper surface SF1 at the position N3. Referring to FIG. 1(A), the protrusion PP of the blade edge 51 is disposed between the side ED1 and the side portion PS on the upper surface SF1 of the glass substrate 4, and the side of the blade edge 51 is placed. The PS is disposed between the protrusions PP and the side ED2. Next, the pressed blade tip 51 slides on the upper surface SF1 of the glass substrate 4 (see an arrow in the drawing). The blade edge 51 (FIG. 1) is slid on the upper surface SF1 in the direction DB from the side portion PS toward the protrusion portion PP. In other words, the blade edge 51 (FIG. 1) is slid in the direction DB projected from the side portion PS toward the projection portion PP in the upper surface SF1. The direction DB is substantially projected in a direction in which the extending direction of the side portion PS near the protrusion portion PP is projected on the upper surface SF1. By this sliding, the groove line TL is formed in the same manner as in the first embodiment. In the case where the groove line TL is formed, in the present embodiment, the blade edge 51 is displaced from the position N3 to the position N2, and further displaced from the position N2 to the position N1. That is, referring to Fig. 1, the blade edge 51 is displaced in the direction DB from the side ED2 toward the side ED1. The direction DB corresponds to a direction in which the direction in which the axial direction AX extending from the blade edge 51 is projected on the upper surface SF1 is opposite. In this case, the cutting edge 51 is advanced on the upper surface SF1 by the shank 52. Next, in the same manner as in the first embodiment (Fig. 5), the crack line CL is formed. The direction in which the crack line CL extends is the same as that of the first embodiment (the dotted arrow in Fig. 5). Therefore, in the present embodiment, the crack line CL (Fig. 5) extends in the direction in which the groove line TL (Fig. 14) extends (the dotted arrow in Fig. 5) and the direction in which the groove line TL is formed (the solid line in Fig. 14). The arrow) is the opposite. In order to select the direction in which the crack line CL is stretched as described above, the method of forming the groove line TL may be appropriately selected. Specifically, the posture of the blade edge 51 may be selected in the same manner as in the first embodiment. According to the study by the inventors, the direction in which the crack line CL extends is the direction in which the groove line TL is formed, and is mainly determined by the posture of the blade tip 51. Further, in the present embodiment, the same modifications as the first modification (Fig. 7 and Fig. 8) and the second modification (Fig. 9) of the first embodiment can be applied. Further, similarly to the second embodiment and its modifications, the auxiliary line AL can be formed before the groove line TL is formed. Next, a modification will be described. First, as in the above-described embodiment, the groove line TL is formed from the position N3 through N2 to N1 by the sliding of the direction of the blade edge 51 (Fig. 1). Thereafter, in the present modification, the sliding of the cutting edge 51 is folded back at the position N1. Next, at the position N1 to the position N2, the blade edge 41 is again slid on the already formed groove line TL. In other words, the end portion of the groove line TL formed by the sliding direction of the blade edge 51 is slid back in the direction DA of the blade edge 51. In response to this re-sliding, the crack line CL is extended from the groove line TL by the above-described portion of the blade edge 51 that is again slid toward the position N3. According to the present modification, it is not necessary to specifically form the auxiliary line AL (FIG. 5) or the like, and the glass substrate 4 can be easily given a start to form the crack line CL. This re-sliding can be performed in the direction DB as in the position N3 to the position N1, but the blade edge 51 is not separated from the upper surface SF of the glass substrate 4 at the position N1 (that is, the state in which the blade edge 51 is in contact with the upper surface SF) Further, the sliding is reversed in the opposite direction, whereby the blade edge 51 can be surely slid again from the position N1 to the position N2 on the already formed groove line TL. Further, in this modification, the groove line TL is formed by the sliding of the blade edge 51, and when the portion which is slid by the blade edge 51 is formed, the load of the blade edge 51 can be increased. Specifically, the load from the position N2 to the position N1 can be increased as compared with the load from the position N3 to the position N2. Thereafter, when the cutting edge 51 is folded back at the position N1 and slid to the position N2, it is preferable to maintain the increased load. Thereby, the load of the blade edge 51 in the section other than the section where the blade edge 51 repeatedly slides (that is, the section between the position N1 and the position N2) can be reduced, and the crack line CL is more likely to be caused by the repeated sliding of the blade edge 51. form. <Embodiment 4> Referring to Fig. 15, in the present embodiment, when the groove line TL is formed by sliding in the direction DB (Fig. 1) of the blade edge 51, the blade edge 51 is located at the edge of the glass substrate 4 The position of the edge ED1 is N0. Thereby, the cutting edge 51 cuts the edge of the glass substrate 4 at the position N0. Taking this as an opportunity, as shown in FIG. 16, the crack line CL extends from the position N0 toward the position N3. According to the present embodiment, it is possible to easily give the glass substrate 4 a start to form the crack line CL without forming the auxiliary line AL (Fig. 5) or the like. Further, the formation of the crack line CL is started by applying a strain stress to the glass substrate 4 such as the strain of the internal stress near the groove line TL due to a specific portion on the groove line TL. The application of the stress is not limited to the formation of the auxiliary line AL described in the first to third embodiments, or the separation of the glass substrate, or the edge of the cut glass substrate 4 described in the fourth embodiment, for example, the knife can be used again. The tip is pressed to or near the formed groove line TL to apply external stress, or is heated by irradiation of laser light or the like. <Supplementary Note> In the above embodiments, when the sliding direction of the blade edge 51 (FIG. 1) forming the groove line TL is the direction DA, the crack line CL is formed in the same direction as the direction in which the groove line TL is formed. . Further, when the sliding direction of the blade edge 51 (FIG. 1) forming the groove line TL is the direction DB, the crack line CL is formed in a direction opposite to the direction in which the groove line TL is formed. In either case, if the axial direction AX of the cutting edge 51 is further inclined from the normal direction of the upper surface SF1 of the glass substrate 4, the extending direction of the crack line CL can be made opposite to the above. That is, in the case where the sliding direction of the blade edge 51 (FIG. 1) forming the groove line TL is the direction DA, the crack line CL can be formed in a direction opposite to the direction in which the groove line TL is formed. Further, when the sliding direction of the blade edge 51 (FIG. 1) forming the groove line TL is the direction DB, the crack line CL can be formed in the same direction as the direction in which the groove line TL is formed. In this case, it is preferable to set the angle AG2>the angle AG1 in FIG. Further, the position at which the stress is applied to form the crack line CL along the groove line TL may be selected in consideration of the direction in which the crack line CL is stretched. For example, when the auxiliary line AL is formed as a stress application, the position at which the auxiliary line AL intersects the groove line TL is selected in consideration of the extending direction of the crack line CL. Based on the above, the method of dividing the glass substrate (brittle substrate) described in the following (1) or (2) can be carried out. (1) The breaking method of the first brittle substrate has the following steps a) to c). a) by causing the blade tip having the protruding portion and the side portion extending from the protruding portion and having the convex shape to slide on one side of the brittle substrate from the protruding portion toward the side portion, thereby causing plastic deformation on one surface A groove line having a groove shape is formed. The groove line is formed as follows: a state in which the brittle substrate is continuously connected in a direction crossing the groove line, which is obtained below the groove line, is a crack-free state. b) forming a crack line by stretching a crack of the brittle substrate along at least a portion of the trench line. By the crack line below the groove line, the fragile substrate is continuously disconnected in a direction crossing the groove line. c) Breaking the brittle substrate along the crack line. Step a) is performed in the step in which the crack line extends along the groove line in the direction opposite to the direction in which the groove line is formed. (2) The breaking method of the second brittle substrate has the following steps a) to c). a) by causing the blade tip having the protruding portion and the side portion extending from the protruding portion and having the convex shape to slide on one side of the brittle substrate from the side portion toward the protruding portion, thereby causing plastic deformation on one surface A groove line having a groove shape is formed. The groove line may be formed as follows: a state in which the brittle substrate is continuously connected in a direction crossing the groove line, that is, a crack-free state is obtained. b) forming a crack line by stretching a crack of the brittle substrate along at least a portion of the trench line. By the crack line below the groove line, the fragile substrate is continuously disconnected in a direction crossing the groove line. c) Breaking the brittle substrate along the crack line. Step a) is carried out in the step b) in which the crack line extends along the groove line in the same direction as the groove line is formed.

4‧‧‧Glass substrate (brittle substrate)
50‧‧‧ cutting instruments
51‧‧‧Tool tip
52‧‧‧Knife
AL‧‧‧Auxiliary line
AG1‧‧‧ angle
AG2‧‧‧ angle
AX‧‧‧ axial
CL‧‧‧ crack line
DA‧‧‧ directions
DB‧‧‧ direction
DC‧‧ direction
DT‧‧‧ thickness direction
ED1‧‧‧ side
ED2‧‧‧ side
ED3‧‧‧ side
ED4‧‧‧ side
IB‧‧ arrow
N0‧‧‧ position
N1‧‧‧ position
N2‧‧‧ position
N3‧‧‧ position
N4‧‧‧ position
SD1‧‧‧ top surface (1st side)
SD2‧‧‧ side (2nd side)
SD3‧‧‧ side (3rd side)
SF1‧‧‧ upper surface (one side)
SF2‧‧‧ lower surface (the other side)
S30‧‧‧ steps
S50‧‧ steps
S60‧‧ steps
TL‧‧‧ trench line
PP‧‧‧Protruding
PS‧‧‧ side

Fig. 1(A) is a side view schematically showing the configuration of an apparatus used in the method for dividing a brittle substrate according to the first embodiment, and (B) is a view schematically showing an arrow IB of Fig. 1(A). A top view of the configuration of the tool tip of the appliance. Fig. 2 is a flow chart schematically showing the configuration of a method for dividing a brittle substrate according to the first embodiment of the present invention. Fig. 3 is a plan view schematically showing a first step of the breaking method of the brittle substrate according to the first embodiment of the present invention. Fig. 4 is a cross-sectional view showing the structure of a groove line formed in the breaking method of the brittle substrate according to the first embodiment of the present invention. Fig. 5 is a plan view schematically showing a second step of the breaking method of the brittle substrate according to the first embodiment of the present invention. Fig. 6 is a cross-sectional view schematically showing the configuration of a crack line formed in the breaking method of the brittle substrate according to the first embodiment of the present invention. FIG. 7 is a plan view schematically showing a first step of a method of dividing a brittle substrate according to a first modification of the first embodiment of the present invention. FIG. 8 is a plan view schematically showing a second step of the breaking method of the brittle substrate according to the first modification of the first embodiment of the present invention. FIG. 9 is a plan view schematically showing one step of a method of dividing a brittle substrate according to a second modification of the first embodiment of the present invention. Fig. 10 is a plan view schematically showing a first step of the breaking method of the brittle substrate according to the second embodiment of the present invention. Fig. 11 is a plan view schematically showing a second step of the breaking method of the brittle substrate according to the second embodiment of the present invention. Fig. 12 is a plan view schematically showing a third step of the breaking method of the brittle substrate according to the second embodiment of the present invention. Fig. 13 is a plan view schematically showing a step of a method of dividing a brittle substrate according to a modification of the second embodiment of the present invention. Fig. 14 is a plan view schematically showing one step of a method of dividing a brittle substrate according to a third embodiment of the present invention. Fig. 15 is a plan view schematically showing a first step of the breaking method of the brittle substrate according to the fourth embodiment of the present invention. Fig. 16 is a plan view schematically showing a second step of the breaking method of the brittle substrate according to the fourth embodiment of the present invention.

4‧‧‧Glass substrate (brittle substrate)

AL‧‧‧Auxiliary line

CL‧‧‧ crack line

ED1‧‧‧ side

ED2‧‧‧ side

ED3‧‧‧ side

ED4‧‧‧ side

N1‧‧‧ position

N2‧‧‧ position

N3‧‧‧ position

SF1‧‧‧ upper surface (one side)

TL‧‧‧ trench line

Claims (3)

A method for breaking a brittle substrate, comprising the steps of: a) forming a blade having a protrusion and a side portion extending from the protrusion and having a convex shape on one side of the brittle substrate, from the protrusion Sliding in the direction of the side portion, plastically deforming on the one surface to form a groove line having a groove shape; the groove line is formed in such a manner as to be formed below the groove line, the brittle substrate a state of continuous connection in a direction intersecting the groove line, that is, a crack-free state; b) forming a crack line by extending a crack of the brittle substrate along at least a portion of the groove line; </ RTI> below the trench line, the brittle substrate is continuously connected to the direction intersecting the trench line; and c) the fragile substrate is separated along the crack line; and the step a) is In the step b), the direction in which the crack line extends along the groove line is the same as the direction in which the groove line is formed. A method for breaking a brittle substrate, comprising the steps of: a) facing a blade tip having a protrusion and a side portion extending from the protrusion and having a convex shape on one side of the brittle substrate; The protruding portion is slid in a direction to be plastically deformed on the one surface to form a groove line having a groove shape; the groove line is formed in such a manner as to be formed below the groove line, the brittle substrate a state of continuous connection in a direction intersecting the groove line, that is, a crack-free state; b) forming a crack line by extending a crack of the brittle substrate along at least a portion of the groove line; and by the crack line And below the groove line, the brittle substrate is continuously connected to the direction intersecting the groove line; c) the fragile substrate is separated along the crack line; and the step a) is In the step b), the direction in which the crack line extends along the groove line is opposite to the direction in which the groove line is formed. The breaking method of the brittle substrate according to claim 1 or 2, wherein the cutting edge has first to third faces adjacent to each other, a vertex of the first to third faces meeting, and the second and third faces The ridge line is formed by the apex of the blade tip, and the side portion of the blade edge is formed by the ridge line.