JPWO2017056876A1 - Method for dividing brittle substrate - Google Patents

Abstract

A cutting edge (51) having a protruding portion (PP) and a side portion (PS) extending from the protruding portion (PP) and having a convex shape is formed on one surface (SF1) of the brittle substrate (4). ) To the side portion (PS) to cause plastic deformation on one surface (SF1), thereby forming a trench line (TL) having a groove shape. 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 divided along the crack line (CL). The formation process of the trench line (TL) is the direction in which the crack line (CL) extends along the trench line (TL) in the formation process of the crack line (CL) and the direction in which the trench line (TL) is formed. It is done to be the same.

Description

  The present invention relates to a method for dividing a brittle substrate.

  In the manufacture of electrical equipment such as flat display panels or solar cell panels, it is often necessary to break a brittle substrate such as a glass substrate. First, a scribe line is formed on the substrate, and then the substrate is divided along the scribe line. The scribe line can be formed by mechanically processing the substrate using a cutter. When the cutter slides or rolls on the substrate, a trench due to plastic deformation is formed on the substrate, and at the same time, a vertical crack is formed below the trench. Thereafter, stress is applied, which is called a breaking process. The substrate is divided by causing the crack to proceed completely in the thickness direction by the breaking process.

  The step of dividing the substrate is often performed immediately after the step of forming a scribe line on the substrate. However, it has also been proposed to perform a step of processing the substrate between the step of forming the scribe line and the breaking step. The process of processing a board | substrate is a process of providing a certain member on a board | substrate, for example.

  For example, according to the technique of International Publication No. 2002/104078, in the method of manufacturing an organic EL display, a scribe line is formed on a glass substrate for each region to be each organic EL display before mounting a sealing cap. For this reason, the contact between the sealing cap and the glass cutter, which becomes a problem when the scribe line is formed on the glass substrate after the sealing cap is provided, can be avoided.

  Further, for example, according to the technique of International Publication No. 2003/006391, in a method for manufacturing a liquid crystal display panel, two glass substrates are bonded together after a scribe line is formed. As a result, two brittle substrates can be simultaneously broken in a single breaking step.

International Publication No. 2002/104078 International Publication No. 2003/006391

  According to the above-described conventional technique, the brittle substrate is processed after the scribe line is formed, and then the breaking process is performed by applying stress. This means that vertical cracks already exist when processing into brittle substrates. The further extension in the thickness direction of the vertical cracks may occur unintentionally during the processing, so that the brittle substrate that should be integrated may be divided during the processing. Also, even when the substrate processing step is not performed between the scribe line forming step and the substrate breaking step, the substrate is usually transported or stored after the scribe line forming step and before the substrate breaking step. In this case, the substrate may be unintentionally divided. Therefore, it is extremely useful if the position where the brittle substrate is to be divided can be defined by a line not accompanied by a vertical crack (in other words, a line in a “crackless state” described later). Even if it is not necessary to consider the unintentional division as described above, if the position where the brittle substrate is divided can be defined by a line without a vertical crack, the line It is sufficient even if the load for pressing the blade edge against the brittle substrate is smaller in the forming step. Reduction of the load on the cutting edge is useful for reducing wear on the cutting edge or damage to the brittle substrate surface. However, a technique for forming a line without a vertical crack, which can define a position where the brittle substrate is to be divided, by using sliding of the blade edge has not been sufficiently studied so far. Rather, such a line without a vertical crack has usually been recognized only as a defective line due to insufficient load on the cutting edge.

  The present invention has been made to solve the above-described problems, and the purpose of the present invention is to provide a brittle substrate in which the position where the brittle substrate is to be divided can be defined by a line without a vertical crack. It is to provide a method of dividing.

  The method for cutting a brittle substrate according to one aspect of the present invention includes the following steps a) to c).

  a) On one surface by sliding a blade edge having a projection and a side portion extending from the projection and having a convex shape on one surface of the brittle substrate in a direction from the projection to the side portion. By generating plastic deformation, a trench line having a groove shape is formed. The trench line is formed so as to obtain a crackless state in which the brittle substrate is continuously connected in the direction intersecting the trench line below the trench line.

  b) A crack line is formed by extending a crack in the brittle substrate along at least a portion of the trench line. The brittle substrate is disconnected continuously in the direction crossing the trench line below the trench line by the crack line.

  c) The brittle substrate is divided along the crack line.

  Step a) is performed such that the direction in which the crack line extends along the trench line in step b) is the same as the direction in which the trench line was formed.

  The method for cutting a brittle substrate according to another aspect of the present invention includes the following steps a) to c).

  a) By sliding a cutting edge having a projection and a side portion extending from the projection and having a convex shape on one surface of the brittle substrate in a direction from the side toward the projection, By generating plastic deformation, a trench line having a groove shape is formed. The trench line is formed so as to obtain a crackless state in which the brittle substrate is continuously connected in the direction intersecting the trench line below the trench line.

  b) A crack line is formed by extending a crack in the brittle substrate along at least a portion of the trench line. The brittle substrate is disconnected continuously in the direction crossing the trench line below the trench line by the crack line.

  c) The brittle substrate is divided along the crack line.

  Step a) is performed such that the direction in which the crack line extends along the trench line in step b) is opposite to the direction in which the trench line was formed.

  According to the present invention, a trench line having no crack is formed below the line that defines the position where the brittle substrate is divided. The crack line to be used as a direct trigger for the division is formed by extending the crack along the trench line after the formation. Thereby, the position where a brittle board | substrate will be parted can be prescribed | regulated by the line which does not accompany a vertical crack.

FIG. 1A is a side view schematically showing the configuration of an instrument used in the method for cutting a brittle substrate in Embodiment 1 of the present invention, and the configuration of the cutting edge of the instrument is the viewpoint of arrow IB in FIG. It is a top view (B) shown roughly by. It is a flowchart which shows schematically the structure of the brittle board | substrate parting method in Embodiment 1 of this invention. It is a top view which shows roughly the 1st process of the cutting method of a brittle board | substrate in Embodiment 1 of this invention. It is an end elevation which shows roughly the structure of the trench line formed in the cutting method of the brittle board | substrate in Embodiment 1 of this invention. It is a top view which shows roughly the 2nd process of the cutting method of a brittle board | substrate in Embodiment 1 of this invention. It is an end elevation which shows roughly the structure of the crack line formed in the cutting method of the brittle board | substrate in Embodiment 1 of this invention. It is a top view which shows roughly the 1st process of the cutting method of the brittle board | substrate of the 1st modification of Embodiment 1 of this invention. It is a top view which shows roughly the 2nd process of the cutting method of the brittle board | substrate of the 1st modification of Embodiment 1 of this invention. It is a top view which shows roughly 1 process of the cutting method of the brittle board | substrate of the 2nd modification of Embodiment 1 of this invention. It is a top view which shows roughly the 1st process of the cutting method of the brittle board | substrate in Embodiment 2 of this invention. It is a top view which shows roughly the 2nd process of the cutting method of a brittle board | substrate in Embodiment 2 of this invention. It is a top view which shows roughly the 3rd process of the cutting method of a brittle board | substrate in Embodiment 2 of this invention. It is a top view which shows roughly 1 process of the cutting method of the brittle board | substrate of the modification of Embodiment 2 of this invention. It is a top view which shows roughly 1 process of the cutting method of the brittle board | substrate in Embodiment 3 of this invention. It is a top view which shows roughly the 1st process of the cutting method of the brittle board | substrate in Embodiment 4 of this invention. It is a top view which shows roughly the 2nd process of the cutting method of a brittle board | substrate in Embodiment 4 of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

<Embodiment 1>
(Configuration of the cutting tool)
With reference to FIG. 1, the structure of the cutting tool 50 used for the formation process of the trench line in the cutting method of the glass substrate 4 (brittle substrate) of this Embodiment is demonstrated first. The cutting instrument 50 has a cutting edge 51 and a shank 52. The blade edge 51 is held by being fixed to a shank 52 as its holder.

  The blade edge 51 is provided with a top surface SD1 (first surface) and a plurality of surfaces surrounding the top surface SD1. The plurality of surfaces include a side surface SD2 (second surface) and a side surface SD3 (third surface). The top surface SD1, the side surfaces SD2, and SD3 (first to third surfaces) face different directions and are adjacent to each other. The blade edge 51 has a vertex at which the top surface SD1, the side surfaces SD2 and SD3 merge, and the protrusion PP of the blade edge 51 is configured by this vertex. Further, the side surfaces SD2 and SD3 form ridge lines constituting the side portion PS of the blade edge 51. The side part PS extends linearly from the protrusion part PP. Moreover, since the side part PS is a ridgeline as mentioned above, it has the convex shape extended linearly.

  The cutting edge 51 is preferably a diamond point. That is, the cutting edge 51 is preferably made of diamond from the viewpoint that the hardness and the surface roughness can be reduced. More preferably, the cutting edge 51 is made of single crystal diamond. More preferably, crystallographically, the top surface SD1 is a {001} plane, and each of the side surfaces SD2 and SD3 is a {111} plane. In this case, although the side surfaces SD2 and SD3 have different orientations, they are crystal surfaces that are equivalent to each other in terms of crystallography.

  Diamond that is not a single crystal may be used. For example, polycrystalline diamond synthesized by a CVD (Chemical Vapor Deposition) method may be used. Alternatively, sintered diamond obtained by bonding polycrystalline diamond particles, which are sintered from fine graphite or non-graphitic carbon without containing a binder such as an iron group element, with a binder such as an iron group element is used. May be.

  The shank 52 extends along the axial direction AX. The blade edge 51 is preferably attached to the shank 52 so that the normal direction of the top surface SD1 is approximately along the axial direction AX.

(Glass substrate cutting method)
In the present embodiment, a method for dividing the glass substrate 4 (FIG. 2) including a step of sliding the blade edge 51 (FIG. 1) in the direction DA on the upper surface SF1 of the glass substrate 4 will be described.

  The glass substrate 4 to be divided has an upper surface SF1 (one surface) and an opposite lower surface SF2 (other surface). Referring to FIG. 3, the edge surrounding upper surface SF1 includes side ED1 (first side) and side ED2 (second side) facing each other. In the example shown in FIG. 3, the edge is rectangular. Therefore, the sides ED1 and ED2 are sides parallel to each other. In the example shown in FIG. 3, the sides ED1 and ED2 are rectangular short sides. The glass substrate 4 has a thickness direction DT perpendicular to the upper surface SF1.

  2 and 3, trench line TL is formed in step S30. Specifically, the following steps are performed.

  First, the protrusion PP and the side part PS of the blade edge 51 are pressed against the upper surface SF1 at the position N1. Details of the position N1 will be described later. With reference to FIG. 1A, the cutting edge 51 is pressed such that the projection PP of the cutting 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 cutting edge 51 is pressed. The side PS is arranged between the protrusion PP and the side ED2.

  Next, the pressed blade edge 51 is slid on the upper surface SF1 of the glass substrate 4 (see the arrow in FIG. 3). The blade edge 51 (FIG. 1) is slid on the upper surface SF1 in the direction DA from the projecting portion PP toward the side portion PS. In other words, the blade edge 51 is slid in the direction DA in which the direction from the protrusion PP to the side PS is projected onto the upper surface SF1. The direction DA is approximately along the direction in which the extending direction of the side portion PS in the vicinity of the projecting portion PP is projected onto the upper surface SF1. This sliding causes plastic deformation on the upper surface SF1. As a result, trench lines TL (five lines in the drawing) having a groove shape are formed on the upper surface SF1. As described above, the trench line TL is generated by plastic deformation of the glass substrate 4, and the plastic deformation is sufficiently formed with a low load that the surface of the glass substrate cannot be cut, but the glass substrate 4 may be cut slightly. However, it is preferable that such shaving does not occur because undesirable fine fragments can be generated.

  The formation of the trench line TL is performed between the position N1 and the position N3. A position N2 is located between the positions N1 and N3. Therefore, trench line TL is formed between positions N1 and N2 and between positions N2 and N3.

  The positions N1 and N3 may be located away 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 formed trench line TL is separated 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.

  Of the positions N1 and N2, the position N1 is closer to the side ED1, and the position N2 of the positions N1 and N2 is closer to the side ED2. In the example shown in FIG. 3, the position N1 is close to the side ED1 of the sides ED1 and ED2, and the position N2 is close to the side ED2 of the sides ED1 and ED2, but both the positions N1 and N2 are either the side ED1 or ED2. It may be located near either.

  When the trench line TL is formed, in the present embodiment, the blade edge 51 is displaced from the position N1 to the position N2, and is further displaced from the position N2 to the position N3. That is, referring to FIG. 1, the blade edge 51 is displaced in a direction DA that is a direction 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 onto the upper surface SF1. In this case, the blade edge 51 is dragged on the upper surface SF <b> 1 by the shank 52.

  Referring to FIG. 4, the process of forming trench line TL is continuously connected in a direction DC where glass substrate 4 intersects the extending direction of trench line TL (the lateral direction in FIG. 3) below trench line TL. It is performed so that the crackless state which is the state which is in the state can be obtained. In the crackless state, the trench line TL is formed by plastic deformation, but no crack is formed along the trench line TL. Therefore, even if an external force that simply generates a bending moment or the like is applied to the glass substrate 4 as in the conventional break process, the division along the trench line TL does not easily occur. For this reason, in the crackless state, the dividing step along the trench line TL is not performed. In order to obtain a crackless state, the load applied to the blade edge 51 is small enough not to generate a crack at the time of scribing, and plastic deformation that creates a state of internal stress that can generate a crack in a later process is performed. It is adjusted to the extent that it occurs.

  The crackless state can be maintained for a desired time. In order to maintain the crackless state, an operation in which excessive stress is applied to the glass substrate 4 in the trench line TL, for example, heating with application of a large external stress that causes damage to the substrate or a large temperature change, Should be avoided. Meanwhile, the glass substrate 4 can be transported, stored, or processed. The processing of the glass substrate 4 may be a step of providing a member (not shown) on the glass substrate 4, for example.

  Referring to FIG. 5, in step S50 (FIG. 2) after step S30 (FIG. 2), the crack of glass substrate 4 in the thickness direction DT is extended along at least part of trench line TL. In FIG. 5, the crack of the glass substrate 4 is extended along the part between the position N2 and the position N3 among the formed trench lines TL (FIG. 3). As a result, a crack line CL is formed.

  In the present embodiment, the formation of the crack line CL is started when the assist line AL intersecting with the trench line TL at the position N2 is formed. The assist line AL may be a normal scribe line with a crack in the thickness direction DT, and releases internal stress distortion in the vicinity of the trench line TL. The method of forming the assist line AL is not particularly limited, but may be formed using the edge of the upper surface SF1 as a base point as shown in FIG.

  Referring to FIG. 6, the continuous connection is broken in the direction DC intersecting the extending direction (lateral direction in FIG. 5) of the trench line TL below the trench line TL by the crack line CL. . Here, “continuous connection” means a connection that is not interrupted by a crack. In addition, in the state where the continuous connection is cut as described above, the portions of the glass substrate 4 may be in contact with each other through the cracks of the crack line CL. Further, a slightly continuous connection may be left immediately below the trench line TL.

  In the present embodiment, the direction in which the crack line CL (FIG. 5) extends along the trench line TL (FIG. 3) (broken line arrow in FIG. 5) is the direction in which the trench line TL is formed (solid line in FIG. 3). Same as arrow). In order to select the extension direction of the crack line CL as such, the formation method of the trench line TL may be appropriately selected.

  According to the study of the present inventor, when the trench line TL is formed by sliding the blade edge 51 (FIG. 1) in the direction DA as in the present embodiment, the axial direction AX of the blade edge 51 is the glass substrate 4. If it is close to perpendicular to the upper surface SF1, the extension direction of the crack line CL is the same as the extension direction of the trench line TL. When the trench line TL is formed by sliding the blade edge 51 (FIG. 1) in the direction DA as in the present embodiment, the axial direction AX is the method of the upper surface SF1 of the glass substrate 4 contrary to the above. If it is greatly inclined from the line direction, the extension direction of the crack line CL is opposite to the extension direction of the trench line TL. When the axial direction AX is an intermediate angle between these, the extension direction of the crack line CL becomes unstable and it is difficult to predict it.

  Therefore, in order to make the extension direction of the crack line CL more surely the same as the formation direction of the trench line TL, the cutting edge 51 of the cutting edge 51 is set so that the angle of the axial direction AX (FIG. 1) approaches more perpendicular to the upper surface SF1. Just adjust your posture. 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 is more reliably set to the trench line. It can be the same as the TL extension direction.

  When the posture of the blade edge 51 (FIG. 1) is adjusted as described above, the angle AG1 increases and the angle AG2 decreases. According to the first experiment using the blade edge 51 having an angle of 158 ° between the top surface SD1 and the side portion PS, when the angle AG1 = 5 ° and the angle AG2 = 17 °, the extension direction of the crack line CL is The direction of extension of the trench line TL was reversed. When the angle AG1 = angle AG2 = 11 ° by adjusting the axial direction AX, the extension direction of the crack line CL is the same as the extension direction of the trench line TL. According to the second experiment using the cutting edge 51 having an angle of 165 ° between the top surface SD1 and the side portion PS, when the angle AG1 = 5 ° and the angle AG2 = 10 °, the extension direction of the crack line CL is The direction of extension of the trench line TL was reversed. When the angle AG1 = 7 ° and the angle AG2 = 8 ° by adjusting the axial direction AX, the extension direction of the crack line CL is the same as the extension direction of the trench line TL. Since the protrusion PP of the blade edge 51 is desired to be 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 extension direction of the crack line CL the same as the extension direction of the trench line TL, it is preferable that the angle AG2 ≦ the angle AG1.

  When the extension direction of the crack line CL is selected as described above, the glass in the thickness direction DT (FIG. 6) extends from the position N2 toward the position N3 along the trench line TL (see the broken line arrow in FIG. 5). The crack of the substrate 4 extends. Note that the crack line CL is less likely to be formed in the direction from the position N2 to the position N1 than in the direction from the position N2 to the position N3. That is, the ease of extension of the crack line CL has a direction dependency. Therefore, the phenomenon that the crack line CL is formed between the positions N2 and N3 but not between the positions N2 and N1 may occur. The present embodiment is intended to divide the glass substrate 4 along the positions N2 and N3, and is not intended to separate the glass substrate 4 along the positions N2 and N1. Therefore, it is necessary to form the crack line CL between the positions N2 and N3, but 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 divided along the crack line CL. That is, a so-called break process is performed. The breaking process can be performed, for example, by applying an external force to the glass substrate 4. For example, a stress that opens the crack line CL is applied to the glass substrate 4 by pressing the stress applying member on the lower surface SF <b> 2 toward the crack line CL (FIG. 6) on the upper surface SF <b> 1 of the glass substrate 4. Note that, when the crack line CL is completely advanced in the thickness direction DT at the time of formation, the formation of the crack line CL and the division of the glass substrate 4 may occur at the same time.

  Thus, the glass substrate 4 is divided. Note that the crack line CL forming process described above is essentially different from a so-called break process. In the breaking process, cracks that have already been formed are further extended in the thickness direction to completely separate the substrate. On the other hand, the formation process of the crack line CL brings about a change from a crackless state obtained by forming the trench line TL to a state having cracks. This change is considered to be caused by the release of internal stress that the crackless state has. The state of the plastic deformation at the time of forming the trench line TL and the magnitude and directionality of the internal stress generated by the formation of the trench line TL are the same as in the case where rolling of the rotary blade is used, as in this embodiment. This is considered to be different from the case where the sliding of the blade edge is used, and when the sliding of the blade edge is used, cracks are likely to occur in a wider scribe condition. In addition, stress application is necessary as a trigger for releasing the internal stress. In the present embodiment, the formation of the assist line AL acts as such a trigger.

  Although the case where the upper surface SF1 is flat has been described above, the upper surface may be curved. Further, although the case where the trench line TL is linear has been described, the trench line may be curved. Moreover, although the case where the glass substrate 4 was used as a brittle board | substrate was demonstrated, the brittle board | substrate may be made from brittle materials other than glass, for example, may be made from ceramics, silicon, a compound semiconductor, sapphire, or quartz.

(effect)
According to the present embodiment, a trench line TL (FIG. 4) having no crack is formed below the line that defines the position where the glass substrate 4 is divided. The crack line CL (FIG. 6) to be used as a direct trigger for the division is formed by extending the crack along the trench line TL after the formation. Thereby, the position where the glass substrate 4 will be divided can be defined by the trench line TL which is a line not accompanied by a vertical crack.

  As described above, the trench line TL, which is a line without a vertical crack, is easy to form even if the load pressing the blade edge 51 against the glass substrate 4 is relatively small as compared with a normal scribe line with a vertical crack. Reduction of the load on the blade edge 51 is useful for reducing wear on the blade edge 51 or damage on the upper surface SF1 of the glass substrate 4.

  Further, when the cutting edge 51 is slid toward the direction DA (FIG. 1) as in the present embodiment, the local cutting edge 51 is locally compared to the case where the cutting edge 51 is slid toward the direction DB. Wear is less likely to occur. Thereby, the lifetime of the blade edge 51 is lengthened.

  In addition, the glass substrate 4 (FIG. 3) after the formation of the trench line TL and before the formation of the crack line CL has the crack line CL still formed while the position where the glass substrate 4 is divided is defined by the trench line TL. It is in a state where no breakage occurs easily. By using this state, it is possible to prevent the glass substrate 4 from being unintentionally divided before the time point at which the glass substrate 4 is to be divided, while predefining the position at which the glass substrate 4 is divided. For example, it is possible to prevent the glass substrate 4 from being unintentionally divided during conveyance. Further, it is possible to prevent the glass substrate 4 from being unintentionally divided during some processing to the glass substrate 4.

  Further, unlike the second embodiment described later, in the present embodiment, the assist line AL (FIG. 5) is not yet formed at the time when the trench line TL is formed (FIG. 3). Therefore, the crackless state can be maintained more stably without being affected by the assist line AL.

(First modification)
Referring to FIG. 7, the first modified example relates to a case where the start of formation of crack line CL (FIG. 5) cannot be obtained sufficiently at the intersection of assist line AL and trench line TL at position N2. It is. Referring to FIG. 8, by applying an external force that generates a bending moment or the like to glass substrate 4, a crack in thickness direction DT extends along assist line AL, and as a result, glass substrate 4 is separated. . This triggers the formation of the crack line CL. According to this modification, the crack line CL can be more reliably formed from the trench line TL.

  In this modification, the distortion of the internal stress in the vicinity of the trench line TL is released by the separation of the glass substrate 4, thereby starting the formation of the crack line CL. Therefore, the assist line AL itself may be a crack line CL formed by applying stress to the trench line TL.

  In FIG. 7, the assist line AL is formed on the upper surface SF1 of the glass substrate 4, but the assist line AL may be formed on the lower surface SF2. In this case, the assist line AL and the trench line TL intersect each other at the position N2 in the planar layout, but do not directly contact each other.

(Second modification)
Referring to FIG. 9, in the second modified example, when the trench line TL is formed in step S30 (FIG. 2), the blade edge 51 is positioned on the upper surface SF1 of the glass substrate 4 as compared with the position N3. Pressed with greater force at N2. Specifically, the load on the blade edge 51 is reduced when the formation of the trench line TL reaches the position N4 with the position N4 as the position between the positions N3 and N2. In other words, the load on the cutting edge 51 is increased between the positions N1 and N4 that are the start ends of the trench line TL, as compared with the position N3. Thereby, formation of the crack line CL from the position N2 can be easily induced while reducing a load at a portion other than the start end portion.

<Embodiment 2>
A method for dividing the glass substrate 4 in the present embodiment will be described below with reference to FIGS.

  Referring to FIG. 10, in the present embodiment, unlike the first embodiment, assist line AL is formed before formation of trench line TL. The method of forming the assist line AL is the same as that in 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 in step S30 (FIG. 2), a trench line TL is formed. The method of forming the trench line TL itself is the same as that in FIG. 3 (Embodiment 1). The assist line AL and the trench line TL intersect each other at the position N2.

  Referring to FIG. 12, next, the glass substrate 4 is separated along the assist line AL by a normal breaking process in which an external force that generates a bending moment or the like is applied to the glass substrate 4. Thereby, as step S50 (FIG. 2), formation of the crack line CL similar to that of the first embodiment is started (see the broken line arrow in the figure). In FIG. 10, the assist line AL is formed on the upper surface SF <b> 1 of the glass substrate 4, but the assist line AL for separating the glass substrate 4 may be formed on the lower surface SF <b> 2 of the glass substrate 4. In this case, the assist line AL and the trench line TL intersect each other at the position N2 in the planar layout, but do not directly contact each other.

  The configuration other than the above is almost the same as the configuration of the first embodiment described above.

  Next, a modified example will be described with reference to FIG. In this modification, when the trench line TL is formed in step S30 (FIG. 2), the blade edge 51 is pressed against the upper surface SF1 of the glass substrate 4 with a greater force at the position N2 than at the position N3. Specifically, the load on the blade edge 51 is reduced when the formation of the trench line TL reaches the position N4 with the position N4 as the position between the positions N3 and N2. In other words, the load on the cutting edge 51 is increased between the positions N1 and N4 that are the start ends of the trench line TL, as compared with the position N3. Thereby, formation of the crack line CL from the position N2 can be easily induced while reducing a load at a portion other than the start end portion.

<Embodiment 3>
In the present embodiment, unlike Embodiments 1 and 2, trench line TL is formed by sliding blade edge 51 (FIG. 1) on upper surface SF1 of glass substrate 4 in direction DB instead of direction DA. The Specifically, the following steps are performed.

  Referring to FIG. 14, first, the protrusion PP and the side PS of the blade edge 51 are pressed against the upper surface SF1 at a position N3. With reference to FIG. 1A, the cutting edge 51 is pressed such that the projection PP of the cutting 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 cutting edge 51 is pressed. The side PS is arranged between the protrusion PP and the side ED2.

  Next, the pressed blade edge 51 is slid on the upper surface SF1 of the glass substrate 4 (see the arrow in the figure). The blade edge 51 (FIG. 1) is slid on the upper surface SF1 in the direction DB from the side portion PS toward the projection portion PP. In other words, the blade edge 51 (FIG. 1) is slid in a direction DB in which the direction from the side part PS to the projection part PP is projected onto the upper surface SF1. The direction DB is approximately along the direction in which the extending direction of the side portion PS in the vicinity of the protrusion PP is projected onto the upper surface SF1. By this sliding, a trench line TL is formed as in the first embodiment.

  When the trench line TL is formed, in the present embodiment, the blade edge 51 is displaced from the position N3 to the position N2, and is further displaced from the position N2 to the position N1. That is, referring to FIG. 1, the blade edge 51 is displaced in a direction DB that is a direction from the side ED2 toward the side ED1. The direction DB corresponds to a direction opposite to the direction in which the axial direction AX extending from the blade edge 51 is projected onto the upper surface SF1. In this case, the blade edge 51 is pushed forward on the upper surface SF 1 by the shank 52.

  Next, the crack line CL is formed as in the first embodiment (FIG. 5). The extension direction of the crack line CL is the same as that in the first embodiment (broken line arrow in FIG. 5). Therefore, in the present embodiment, the direction in which the crack line CL (FIG. 5) extends along the trench line TL (FIG. 14) (the broken line arrow in FIG. 5) is the direction in which the trench line TL is formed (in FIG. 14). It is the opposite of the solid arrow). In order to select the extension direction of the crack line CL as such, the formation method of the trench 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 present inventor, the extending direction of the crack line CL is mainly determined by the posture of the cutting edge 51, not the forming direction of the trench line TL.

  Also in the present embodiment, a modification similar to the first modification (FIGS. 7 and 8) and the second modification (FIG. 9) in the first embodiment can be applied. Similarly to the second embodiment and the modification thereof, the assist line AL may be formed before the trench line TL is formed.

  Next, a modified example will be described. First, as in the present embodiment, the trench line TL is formed from the position N3 to N1 through the position N3 by sliding the blade edge 51 in the direction DB (FIG. 1). Thereafter, in the present modification, the sliding of the blade edge 51 is turned back at the position N1. Then, the blade edge 41 is slid again on the already formed trench line TL from the position N1 to the position N2. In other words, the sliding of the cutting edge 51 in the direction DA is performed again at the terminal portion of the trench line TL formed by the sliding of the cutting edge 51 in the direction DB. As a result of this re-sliding, the crack line CL extends toward the position N3 from the portion of the trench line TL that has received the re-sliding of the cutting edge 51. According to this modification, it is possible to easily give the glass substrate 4 an opportunity to start the formation of the crack line CL without particularly forming the assist line AL (FIG. 5). This re-sliding may be performed in the direction DB in the same manner as from the position N3 to the position N1, but the blade edge 51 does not move away from the upper surface SF of the glass substrate 4 at the position N1 (that is, the blade edge 51 is moved to the upper surface SF). By turning back and sliding in the opposite direction (while maintaining the contact state), the blade edge 51 can be slid again on the already formed trench line TL from the position N1 to the position N2.

  In this modification, in forming the trench line TL by sliding the blade edge 51, the load on the blade edge 51 may be increased when a portion that is subject to the sliding of the blade edge 51 again is formed. . Specifically, the load from the position N2 to the position N1 may be increased as compared with the load from the position N3 to the position N2. Thereafter, the increased load is preferably maintained even when the blade edge 51 is folded back at the position N1 and slides to the position N2. Thereby, the blade edge 51 is slid in an overlapping manner while reducing the load on the blade edge 51 in a section other than the section in which the blade edge 51 is slid in an overlapping manner (that is, a section between the position N1 and the position N2). Formation of the crack line CL from the section to be easily induced.

<Embodiment 4>
Referring to FIG. 15, in the present embodiment, when the trench line TL is formed by sliding the blade edge 51 in the direction DB (FIG. 1), the edge 51 is the edge that is the edge of the glass substrate 4. Passes through a position N0 located at ED1. Accordingly, the blade edge 51 cuts down the edge of the glass substrate 4 at the position N0. As a result, 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 an opportunity to start the formation of the crack line CL without particularly forming the assist line AL (FIG. 5).

  The formation of the crack line CL is started by applying stress to the glass substrate 4 at a predetermined location on the trench line TL so as to release the distortion of internal stress in the vicinity of the trench line TL. The application of stress is not limited to the formation of the assist line AL described in the first to third embodiments or the separation of the glass substrate along the assist line AL, or the cut-off of the edge of the glass substrate 4 described in the fourth embodiment. For example, it may be performed by applying an external stress by pressing the blade edge again on or near the formed trench line TL, or by heating by laser light irradiation.

<Appendix>
In the above embodiments, when the sliding direction of the blade edge 51 (FIG. 1) in forming the trench line TL is the direction DA, the crack line CL is formed in the same direction as the direction in which the trench line TL is formed. Is done. When the sliding direction of the blade edge 51 (FIG. 1) in forming the trench line TL is the direction DB, the crack line CL is formed in the direction opposite to the direction in which the trench line TL is formed. In any case, if the axial direction AX of the blade 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 reversed from that described above. That is, when the sliding direction of the blade edge 51 (FIG. 1) in forming the trench line TL is the direction DA, the crack line CL can be formed in a direction opposite to the direction in which the trench line TL is formed. When the sliding direction of the blade edge 51 (FIG. 1) in forming the trench line TL is the direction DB, the crack line CL can be formed in the same direction as the direction in which the trench line TL is formed. In this case, it is preferable that angle AG2> angle AG1 in FIG.

  It should be noted that the stress application position that triggers the formation of the crack line CL along the trench line TL may be selected in consideration of the extending direction of the crack line CL. For example, when the assist line AL is formed as a stress application, the position where the assist line AL intersects the trench line TL is selected in consideration of the extending direction of the crack line CL.

  Based on the above contents, the method for dividing a glass substrate (brittle substrate) described in the following (1) or (2) may be carried out.

  (1) The first brittle substrate cutting method includes the following steps a) to c).

  a) On one surface by sliding a blade edge having a projection and a side portion extending from the projection and having a convex shape on one surface of the brittle substrate in a direction from the projection to the side portion. By generating plastic deformation, a trench line having a groove shape is formed. The trench line is formed so as to obtain a crackless state in which the brittle substrate is continuously connected in the direction intersecting the trench line below the trench line.

  b) A crack line is formed by extending a crack in the brittle substrate along at least a portion of the trench line. The brittle substrate is disconnected continuously in the direction crossing the trench line below the trench line by the crack line.

  c) The brittle substrate is divided along the crack line.

  Step a) is performed such that the direction in which the crack line extends along the trench line in step b) is opposite to the direction in which the trench line was formed.

  (2) The second brittle substrate cutting method includes the following steps a) to c).

  a) By sliding a cutting edge having a projection and a side portion extending from the projection and having a convex shape on one surface of the brittle substrate in a direction from the side toward the projection, By generating plastic deformation, a trench line having a groove shape is formed. The trench line is formed so as to obtain a crackless state in which the brittle substrate is continuously connected in the direction intersecting the trench line below the trench line.

  b) A crack line is formed by extending a crack in the brittle substrate along at least a portion of the trench line. The brittle substrate is disconnected continuously in the direction crossing the trench line below the trench line by the crack line.

  c) The brittle substrate is divided along the crack line.

  Step a) is performed such that the direction in which the crack line extends along the trench line in step b) is the same as the direction in which the trench line was formed.

4 Glass substrate (brittle substrate)
51 Cutting edge AL Assist line CL Crack line SF1 Upper surface (one surface)
TL trench line PP Protrusion PS Side

Claims (3)

a) By sliding a cutting edge having a projection and a side portion extending from the projection and having a convex shape on one surface of the brittle substrate in the direction from the projection to the side, the one Forming a trench line having a groove shape by generating plastic deformation on the surface of the substrate, wherein the trench line is continuous in a direction in which the brittle substrate intersects the trench line below the trench line. Formed so as to obtain a crackless state, which is in a state connected to, and b) forming a crack line by extending a crack of the brittle substrate along at least a part of the trench line, The brittle substrate is below the trench line by the crack line in a direction intersecting the trench line. A continuous connection is broken, and c) a step of cutting the brittle substrate along the crack line,
The step a) is performed such that the direction in which the crack line extends along the trench line in the step b) is the same as the direction in which the trench line is formed.
Method for cutting a brittle substrate. a) By sliding a cutting edge having a protruding portion and a side portion extending from the protruding portion and having a convex shape on one surface of the brittle substrate in the direction from the side portion toward the protruding portion, Forming a trench line having a groove shape by generating plastic deformation on the surface of the substrate, wherein the trench line is continuous in a direction in which the brittle substrate intersects the trench line below the trench line. Formed so as to obtain a crackless state, which is in a state connected to, and b) forming a crack line by extending a crack of the brittle substrate along at least a part of the trench line, The brittle substrate is below the trench line by the crack line in a direction intersecting the trench line. A continuous connection is broken, and c) a step of cutting the brittle substrate along the crack line,
The step a) is performed such that the direction in which the crack line extends along the trench line in the step b) is opposite to the direction in which the trench line is formed.
Method for cutting a brittle substrate. The cutting edge has first to third surfaces adjacent to each other, a vertex where the first to third surfaces meet, and a ridge line formed by the second and third surfaces,
The protruding portion of the cutting edge is configured by the apex, and the side portion of the cutting edge is configured by the ridgeline,
The method for dividing a brittle substrate according to claim 1 or 2.

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