JP6547556B2 - Method of dividing brittle substrate - Google Patents

Description

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

  In the manufacture of electrical devices, such as flat display panels or solar panels, it is often necessary to break the brittle substrate. In a typical dividing method, first, a crack line is formed on a brittle substrate. Here, the "crack line" is one in which a crack partially advanced in the thickness direction of the brittle substrate extends in a line on the surface of the brittle substrate. Next, a so-called break process is performed. Specifically, by applying stress to the brittle substrate, the crack in the crack line is completely advanced in the thickness direction. Thereby, the brittle substrate is divided along the crack line.

  According to Japanese Patent Application Laid-Open No. 9-188534 (Patent Document 1), a depression in the upper surface of the glass plate is generated at the time of scribing. In the above-mentioned publication, this depression is referred to as "scribe line". Further, simultaneously with the formation of the scribe line, a crack extending immediately below the scribe line is generated. Therefore, in the dividing technique of the above-mentioned publication, it can be said that the above-mentioned crack line is formed simultaneously with the formation of the "scribe line".

JP-A-9-188534

  The present inventors have developed an original dividing technology different from the above-mentioned conventional dividing technology. According to this technique, first, a groove shape called a trench line is formed by causing plastic deformation by sliding of the blade edge on the brittle substrate. When the trench line is formed, no crack is formed below it. Thereafter, a crack line is formed by extending the crack along the trench line. That is, unlike the above-mentioned prior art, a trench line without a crack is once formed, and then a crack line is formed along the trench line. Thereafter, a break process is performed along the crack line.

  Trench lines without cracks can be formed by sliding of the cutting edge at lower loads as compared to conventional scribe lines with cracks. The smaller the load on the cutting edge, the smaller the damage to the cutting edge. Therefore, according to this unique cutting technology, the life of the cutting edge can be extended.

  The above-mentioned unique techniques require a process for starting to form a crack line along the trench line. For this purpose, a trigger is required to release the internal stress generated in the brittle substrate due to the formation of the trench line. As one of the methods for providing this trigger, the present inventors have found that the step of forming a normal scribe line to cross the trench line is effective. However, due to this process, the method of dividing a brittle substrate is complicated. Thus, an easier and easier process has been desired.

  The present invention has been made to solve the problems as described above, and an object thereof is to easily form a crack line along a trench line after forming a trench line without a crack below the same. It is an object of the present invention to provide a method of dividing a brittle substrate which can

  The method of dividing a brittle substrate of the present invention includes the following steps.

  By causing the blade to slide at a first speed from a first position to a second position on one surface of the brittle substrate, plastic deformation is generated on the one surface, thereby forming a groove having a groove shape. Trench lines are formed. The step of forming the first trench line is a row so as to obtain a crackless state in which the brittle substrate is continuously connected in the direction intersecting the first trench line below the first trench line. It will be.

  After the step of forming the first trench line, by further sliding the cutting edge from the second position to the third position on one surface of the brittle substrate at a second speed slower than the first speed. By causing plastic deformation on one surface, a second trench line having a groove shape is formed. The step of forming the second trench line is a row so as to obtain a crackless state in which the brittle substrate is continuously connected below the second trench line in the direction crossing the second trench line. It will be.

  In the step of forming the second trench line, the blade edge moved in the step of reaching the third position extends the crack of the brittle substrate along the second trench line from the third position. A crack line of 1 is formed. Below the second trench line, the brittle substrate is broken continuously in the direction crossing the second trench line by the first crack line.

  When the first crack line reaches the second position, the second crack line is formed by extending the crack of the brittle substrate along the first trench line from the second position. Below the first trench line, the brittle substrate is broken continuously in the direction crossing the first trench line by the second crack line.

  The brittle substrate is divided along the first crack line and the second crack line.

  According to the present invention, the cutting edge slid to form the first trench line is further slid to the third position, whereby the second crack line along the first trench line is formed. It is formed. That is, by further continuing the sliding of the cutting edge to form the first trench line, the second crack line can be easily formed along the first trench line.

It is a flowchart which shows roughly the structure of the dividing method of the brittle board | substrate in Embodiment 1 of this invention. FIG. 5 is a top view schematically showing a first step of the method of dividing a brittle substrate in the first embodiment of the present invention. It is a schematic sectional drawing in alignment with line III-III of FIG. It is a schematic sectional drawing in alignment with line IV-IV of FIG. FIG. 5 is a top view schematically showing a second step of the method of dividing a brittle substrate in the first embodiment of the present invention. It is a schematic sectional drawing in alignment with line VI-VI of FIG. It is a schematic sectional drawing in alignment with line | wire VII-VII of FIG. FIG. 7 is a top view schematically showing a third step of the method of dividing a brittle substrate in the first embodiment of the present invention. It is a schematic sectional drawing in alignment with line | wire IX-IX of FIG. It is a microscope picture of the section section which met the 1st crack line of a brittle substrate. It is a microscope picture of the section section which met the 2nd crack line of a brittle substrate. It is a side view which shows roughly the structure of the cutting tool used for the parting method of the brittle board | substrate in Embodiment 1 of this invention. It is a schematic plan view in the viewpoint of arrow XIII of FIG. It is a side view which shows roughly the structure of the cutting tool used for the parting method of the brittle board | substrate in Embodiment 2 of this invention. It is a schematic plan view in the viewpoint of arrow XV of FIG. It is a side view which shows roughly the structure of the cutting tool used for the parting method of the brittle board | substrate in Embodiment 3 of this invention. It is a schematic plan view in the viewpoint of arrow XVII of FIG. FIG. 21 is a top view schematically showing a first step of the method for dividing a brittle substrate in the fourth embodiment of the present invention. It is a schematic sectional drawing in alignment with line XIX-XIX of FIG. FIG. 21 is a top view schematically showing a second step of the method for dividing a brittle substrate in the fourth embodiment of the present invention. It is a schematic sectional drawing in alignment with line | wire XXI-XXI of FIG. FIG. 21 is a top view schematically showing a third step of the method of dividing a brittle substrate in the fourth embodiment of the present invention. It is a schematic sectional drawing in alignment with line XXIII-XXIII of FIG.

  Hereinafter, embodiments of the present invention will be described based on the drawings.

Embodiment 1
(Method of dividing glass substrate)
FIG. 1 is a flow diagram schematically showing the configuration of the method of dividing a brittle substrate in the present embodiment. Hereinafter, this dividing method will be described.

  Referring to FIGS. 2 to 4, first, a glass substrate 4 (brittle substrate) to be divided is prepared. The glass substrate 4 has an upper surface SF1 (one surface) and an opposite lower surface SF2. The glass substrate 4 also has a thickness direction DT (FIG. 3) perpendicular to the top surface SF1. Also, a cutting tool 50 (FIG. 4) having a cutting edge 51 is prepared. The details of the configuration of the cutting tool 50 and its use will be described later.

  Next, the cutting edge 51 disposed apart from the glass substrate 4 is brought close to the glass substrate 4. Thus, the blade tip 51 is brought into contact with the glass substrate 4 at the position N1 (first position) on the upper surface SF1 of the glass substrate 4. The position N1 is away from the edge of the upper surface SF1 of the glass substrate 4.

  Next, in step S10 (FIG. 1), as shown by arrow M1 (FIGS. 2 and 4), on the upper surface SF1 of the glass substrate 4, from position N1 to position N2 different from position N1 (second position The cutting edge 51 is slid until the The first speed, which is the speed of this sliding, may be a typical scribing speed when using a mechanical cutting edge, for example, about 100 mm / sec. This sliding causes plastic deformation on the upper surface SF1. Thereby, a trench line TL1 (first trench line) having a groove shape is formed.

  The trench line TL1 is formed to obtain a crackless state. Here, in the crackless state, the glass substrate 4 is continuously connected in the direction DC (FIG. 3) intersecting the extending direction (the lateral direction in FIGS. 2 and 4) of the trench line TL1 below the trench line TL1. It is about the state that In the crackless state, although the trench line TL1 is formed due to plastic deformation, no crack is formed along it. In order to obtain a crackless state, the load applied to the cutting edge 51 is adjusted to such an extent that a crack does not occur, and a plastic deformation occurs, and a crack will occur later. The crackless state is similarly defined for the other trench lines described later.

  Although the above-mentioned plastic deformation is sufficiently formed with a low load so that the surface of the glass substrate 4 is not scraped, the glass substrate 4 may be scraped slightly. However, it is preferable that such scraping does not occur because it may produce undesirable fine fragments.

  Next, in step S20 (FIG. 1), as shown by arrow M2 (FIGS. 2 and 4), on the upper surface SF1 of the glass substrate 4, from position N2 to position N3 which is different from both position N1 and position N2. The blade tip 51 is further slid to the (third position). The cutting edge 51 is continuously slid from the position N 1 to the position N 3 via the position N 2, including the step of forming the trench line TL 1 described above. The position N3 is away from the edge of the upper surface SF1 of the glass substrate 4. This sliding causes plastic deformation on the upper surface SF1. Thereby, a trench line TL2 (second trench line) having a groove shape is formed.

  The trench line TL2 is formed to obtain a crackless state. The load applied to the cutting edge 51 when the trench line TL2 is formed may be the same as or different from the load applied to the cutting edge 51 when the trench line TL1 is formed. The load control is easier if the two loads are the same.

  The sliding of the cutting edge from the position N2 to the position N3 is performed at a second speed that is lower than the first speed described above. The second velocity is preferably less than 25 mm / sec, more preferably less than 5 mm / sec, for example about 1 mm / sec. For this reason, in view of process efficiency, when the above-mentioned first velocity is 100 mm / sec or more, the second velocity is preferably less than 25% of the first velocity, more preferably more than 5%. small.

  5 to 7, in step S30 (FIG. 1), the blade edge 51 slid in the step of forming the trench line TL2 reaches the position N3, thereby the arrow R1 (FIG. 5 and FIG. 7). As shown in), the crack of the glass substrate 4 in the thickness direction DT is extended along the trench line TL2 from the position N3. Thereby, the crack line CL1 (first crack line) is formed.

  The crackless state of the trench line TL2 disappears due to the formation of the crack line CL1. In other words, the crack line CL1 cuts the continuous connection in the direction DC (FIG. 6) intersecting the extending direction of the trench line TL2 (the lateral direction in FIGS. 5 and 7) below the trench line TL2. I'm tired. Here, "continuous connection" is, in other words, a connection that is not blocked by a crack. In addition, as mentioned above, in the state where the continuous connection is broken, the portions of the glass substrate 4 may be in contact with each other through the cracks of the crack line CL1. In addition, a slightly continuous connection may be left immediately below the trench line TL.

  As described above, the detailed mechanism by which the extension of the crack is initiated is unknown, so it is difficult to predict exactly in advance where the position N3 will be. However, if the second velocity is sufficiently reduced, the position N3 will be sufficiently close to the position N2 with a high probability.

  When the crack line CL1 reaches the position N2 in step S40 (FIG. 1), this causes the thickness along the trench line TL1 from the position N2 as shown by the arrow R2 (FIGS. 5 and 7). The crack of the glass substrate 4 in the longitudinal direction is extended. Thereby, the crack line CL2 (second crack line) is formed. The crackless state of the trench line TL1 disappears due to the formation of the crack line CL2. In other words, the continuous connection is broken in the direction crossing the trench line TL1 below the trench line TL1 by the crack line CL2.

  Referring to FIGS. 8 and 9, in the present embodiment, the sliding of cutting edge 51 is continued even after crack line CL1 is formed as described above. That is, on the upper surface SF1 of the glass substrate 4, as shown by the arrow M3, the cutting edge 51 further slides from the position N3 to a position N4 (fourth position) different from any of the positions N1 to N3 at the second speed. Be moved. This sliding causes plastic deformation on the upper surface SF1. Thereby, a trench line TL3 (third trench line) having a groove shape is formed. The trench line TL3 may be formed to obtain a crackless state. In other words, the blade tip 51 slides at the positions N1 to N4, and a crack occurs at any position N3 between the positions N2 to N4.

  Next, the cutting edge 51 is separated from the glass substrate 4 at the position N4 on the upper surface SF1 of the glass substrate 4. The position N4 is away from the edge of the upper surface SF1 of the glass substrate 4. Thereby, the sliding process of the blade edge 51 from the position N1 to the position N4 via the position N2 and the position N3 in order is completed. The distance by which the cutting edge 51 slides between the position N2 and the position N4 is smaller than the distance by which the cutting edge 51 slides between the position N1 and the position N2. The distance by which the cutting edge 51 slides between the position N2 and the position N4 is preferably 2 mm or more, and more preferably 20 mm or more. For this reason, when the above-mentioned second velocity is 1 mm / sec, the time for which the blade edge 51 slides between the position N2 and the position N4 is preferably 2 seconds or more, more preferably 20 seconds or more. .

  Next, in step S50 (FIG. 1), the glass substrate 4 is divided along the crack line CL1 and the crack line CL2. That is, a so-called break process is performed. The breaking step can be performed by applying an external force to the glass substrate 4. For example, by pressing a stress applying member (for example, a member called "break bar") on lower surface SF2 toward crack line CL1 and crack line CL2 (FIG. 9) on upper surface SF1 of glass substrate 4, the crack Stress is applied to the glass substrate 4 so as to open the crack of the line CL1 and the crack line CL2. When the crack line CL1 and the crack line CL2 progress completely in the thickness direction DT at the time of their formation, the formation of the crack line CL1 and the crack line CL2 and the division of the glass substrate 4 simultaneously occur.

  The process of forming the crack line described above is essentially different from the so-called breaking process. The breaking step is to completely separate the substrate by further extending the already formed crack in the thickness direction. On the other hand, the step of forming the crack line brings about a change from the crackless state obtained by the formation of the trench line to the state having a crack. This change is considered to be caused by the release of the internal stress that the crackless state has.

  Thus, the glass substrate 4 is divided. With regard to the quality of the cross section of the glass substrate 4, the portion along the crack line CL2 is better than the portion along the crack line CL1. Each of FIGS. 10 and 11 is a photomicrograph of a cross section of the glass substrate 4 along the crack line CL1 and the crack line CL2. On the parting plane (FIG. 10) along the crack line CL1, a tooth-like pattern of the shark due to the unevenness was clearly observed in the region of the crack line CL1. On the other hand, such a pattern was not observed on the cross section (FIG. 10) along the crack line CL2, and a better mirror surface was observed.

(Cutting tool)
FIG. 12 is a side view schematically showing the configuration of the cutting tool 50. As shown in FIG. FIG. 13 is a schematic plan view from the viewpoint of arrow XIII in FIG. The direction of the arrow XIII corresponds to the normal direction of the upper surface SF1 of the glass substrate 4. The cutting tool 50 has a cutting edge 51 and a shank 52. The cutting edge 51 is held by being fixed to a shank 52 as its holder.

  The blade edge 51 has a projection PP, ridge portions PS1 to PS4 (first to fourth ridge portions), and side surfaces SD1 to SD4. The side surfaces SD1 to SD4 face in mutually different directions. The ridge PS1 is a boundary between the side surfaces SD1 and SD2. The ridge PS2 is a boundary between the side surfaces SD3 and SD4. The ridge PS3 is a boundary between the side surfaces SD1 and SD3. The ridge PS4 is a boundary between the side surfaces SD2 and SD4. In a plan view (FIG. 13) in which the blade edge 51 is viewed in a field of view of the arrow XIII (FIG. 12), the ridge line portion PS1 and the ridge line portion PS2 are mutually opposite directions from the projection PP on a straight line It extends to In FIG. 12, it is preferable that the angle formed by the ridge portions PS1 and PS2, that is, the angle formed by the direction in which the ridge portion PS1 extends from the protrusion PP and the direction in which the ridge portion PS2 extends from the protrusion PP is an obtuse angle For example, it is about 140 °. As shown in FIGS. 12 and 13, the cutting edge 51 preferably has the shape of the apex of a square weight.

  The ridge portion PS1 is a portion where the surface of the cutting edge 51 merges between the side surface SD1 and the side surface SD2. Therefore, microscopically, the radius of curvature (hereinafter also referred to as the radius of curvature of the ridge portion PS1) ). The radius of curvature is, for example, about several μm to about several tens of μm. The same applies to the ridge line portion PS2. The radius of curvature of the ridge portion PS1 and the radius of curvature of the ridge portion PS2 may be the same as or different from each other.

  The cutting edge 51 is preferably made of diamond in terms of reducing hardness and surface roughness. That is, the cutting edge 51 is preferably a diamond point. More preferably, the cutting edge 51 is made of single crystal diamond. A non-single crystal diamond may be used, and for example, a polycrystalline diamond synthesized by a CVD (Chemical Vapor Deposition) method may be used. Alternatively, sintered diamond in which single crystal or polycrystalline diamond particles are bonded by a binder such as an iron group element may be used. Polycrystalline diamond particles can be made by sintering particulate graphite or non-graphitic carbon without a binder such as iron group elements.

  The shank 52 extends along the axial direction AX. In the example shown in FIG. 12, the cutting edge 51 is a shank so that the axial direction AX is approximately along the intermediate direction between the direction in which the ridge portion PS1 extends from the protrusion PP and the direction in which the ridge portion PS2 extends from the protrusion PP. It is attached to 52.

  Next, how to use the cutting tool 50 when forming the trench lines TL1 to TL3 (FIG. 9) will be described below.

  First, the projection PP of the cutting edge 51 (FIG. 12) is pressed against the upper surface SF1 at the position N1 (FIG. 4). Next, the pressed cutting edge 51 is slid on the upper surface SF1 of the glass substrate 4. The blade tip 51 is slid on the upper surface SF1 in the direction DA from the ridge portion PS2 to the ridge portion PS1. Strictly speaking, the cutting edge 51 is slid in a direction DA in which the direction from the ridge PS2 to the ridge PS1 is projected onto the upper surface SF1. The direction DA is approximately along the direction in which the extension direction of each of the ridge line portion PS1 and the ridge line portion PS2 in the vicinity of the projection PP is projected onto the upper surface SF1. In FIG. 12, the direction DA corresponds to the direction in which the axial direction AX extending from the cutting edge 51 is projected onto the upper surface SF1. Therefore, the cutting edge 51 is dragged by the shank 52 on the upper surface SF1.

  Each of the ridge portion PS1 and the ridge portion PS2 of the cutting edge 51 (FIG. 12) slid on the upper surface SF1 of the glass substrate 4 forms an angle AG1 and an angle AG2 with the upper surface SF1 of the glass substrate 4. Preferably, angle AG2 is greater than angle AG1. When the angle AG2 is smaller than the angle AG1, the crack line CL1 (FIG. 7) is less likely to occur. If the angle AG1 and the angle AG2 are approximately the same, it is likely to be unstable whether or not the crack line CL1 is generated. Although the mechanism in which these events occur is not exactly known, it is presumed that the distribution of stress generated in the glass substrate 4 due to the sliding of the cutting edge 51 is likely to change due to the posture of the cutting edge 51.

(effect)
According to the present embodiment, as shown in FIGS. 2 and 4, the cutting edge 51 slid to form the trench line TL1 is further slid to the position N3. As a result, as shown in FIGS. 5 and 7, the trench line TL2 is formed, and then the crack line CL1 is formed along the trench line TL2. Triggered by the crack line CL1 reaching the position N2, a crack line CL2 is formed along the trench line TL1. From the above, it is possible to easily form the crack line CL2 along the trench line TL1 only by further continuing the sliding of the cutting edge 51 for forming the trench line TL1.

  The position N1 (FIG. 4) is apart from the upper surface SF1 of the glass substrate 4. Thereby, the problem resulting from the collision between the cutting edge 51 and the edge of the upper surface SF1 of the glass substrate 4 can be avoided. Specifically, control of the cutting edge 51 in the height direction is facilitated. Further, damage to the blade tip 51 can be suppressed. In addition, chipping of the edge of the glass substrate 4 can be avoided.

  The position N3 is apart from the edge of the upper surface SF1 of the glass substrate 4 (FIG. 7). Thus, it is not necessary to slide the cutting edge 51 to the edge of the upper surface SF1 of the glass substrate 4 in order to generate the crack line CL1. Therefore, the problem resulting from the cutting edge 51 cutting down the edge of the glass substrate 4 can be avoided. Specifically, control of the cutting edge 51 in the height direction is facilitated. Further, damage to the blade tip 51 can be suppressed. In addition, chipping of the edge of the glass substrate 4 can be avoided.

  In the present embodiment, the sliding of the cutting edge 51 is continued even after the crack line CL1 is formed. That is, by further sliding the cutting edge 51 from the position N3 to the position N4 at the second speed on the upper surface SF1 of the glass substrate 4, the trench line TL3 (FIG. 9) is formed. The reason for this is that it is difficult to predict the timing at which the crack line CL1 is formed, or to implement instantaneous feedback to change the sliding state of the cutting edge 51 at the moment the crack line CL1 is formed. Therefore, continuing formation of the trench line for a certain amount of time after the probability that the crack line CL1 is likely to be formed stochastically, that is, forming the trench line TL3, has a probability of occurrence of the crack line CL1. It is a highly practical method to fully enhance. However, if it is acceptable to use an advanced control system, the above-mentioned feedback is possible, in which case, for example, the end point of the sliding of the cutting edge 51 may be the position N3.

  The position N4 (FIG. 9) is apart from the edge of the upper surface SF1 of the glass substrate 4. Thus, there is no need to slide the cutting edge 51 to the edge of the upper surface SF1 of the glass substrate 4. Therefore, the problem resulting from the cutting edge 51 cutting down the edge of the glass substrate 4 can be avoided. Specifically, control of the cutting edge 51 in the height direction is facilitated. Further, damage to the blade tip 51 can be suppressed. In addition, chipping of the edge of the glass substrate 4 can be avoided.

  The distance that the cutting edge 51 (FIG. 9) slides between the position N2 and the position N4 is smaller than the distance that the cutting edge 51 slides between the position N1 and the position N2. As a result, the ratio of the trench line TL1 to the total distance in which the cutting edge 51 slides is increased. Since the first speed at which the trench line TL1 is formed is faster than the second speed at which the trench line TL2 is formed, the time required for the process is reduced. Also, the cross section along the trench line TL1 (that is, along the crack line CL2) (FIG. 11) has a higher quality cross section than the cross section along the trench line TL2 (that is, along the crack line CL1) Because of this, it is possible to increase the proportion of high quality parts of the cross section.

  The distance by which the blade tip 51 (FIG. 9) slides between the position N2 and the position N4 is preferably 2 mm or more, and more preferably 20 mm or more. Thereby, the crack line CL1 can be generated more reliably.

  The second velocity, which is the sliding velocity of the cutting edge 51 when the trench line TL2 (FIG. 4) is formed, is preferably less than 25 mm / sec, more preferably less than 5 mm / sec. Thereby, the crack line CL1 can be generated more reliably.

Second Embodiment
Referring to FIGS. 14 and 15, in the present embodiment, cutting instrument 50u is used instead of cutting instrument 50 (FIG. 12). The cutting tool 50u has a cutting edge 51u instead of the cutting edge 51 (FIGS. 12 and 13). A top surface TD1 and a plurality of surfaces surrounding the top surface TD1 are provided on the blade edge 51u. The plurality of surfaces include side surfaces TD2 and side surfaces TD3. The top surface TD1, the side surface TD2, and the side surface TD3 face in mutually different directions and are adjacent to each other. The cutting edge 51u has an apex at which the top surface TD1, the side surface TD2, and the side surface TD3 merge, and the projection PP of the cutting edge 51u is configured by the apex. The side surface TD2 and the side surface TD3 form a ridge line portion PS extending from the projection PP.

  Next, two methods of using the cutting tool 50u when forming the trench lines TL1 to TL3 (FIG. 9) will be described below.

  In the first method of use, first, the projection PP of the cutting edge 51u (FIG. 14) is pressed against the upper surface SF1 at the position N1 (FIG. 4). Next, the pressed cutting edge 51 u is slid on the upper surface SF 1 of the glass substrate 4. The blade tip 51u is slid on the upper surface SF1 in the direction DA from the top surface TD1 to the ridge line portion PS. Strictly speaking, the cutting edge 51u is slid in a direction DA in which the direction from the top surface TD1 to the ridge line portion PS is projected onto the top surface SF1. The direction DA is approximately along the direction in which the extending direction of the ridgeline portion PS in the vicinity of the protrusion PP is projected onto the upper surface SF1. In FIG. 14, the direction DA corresponds to the direction in which the axial direction AX extending from the cutting edge 51 u is projected onto the upper surface SF1. Therefore, the cutting edge 51 u is dragged by the shank 52 on the upper surface SF 1. Each of the ridge line portion PS and the top surface TD1 of the cutting edge 51u which is slid on the upper surface SF1 of the glass substrate 4 forms an angle AH1 and an angle AH2 with the upper surface SF1 of the glass substrate 4. In order to facilitate generation of the crack line CL1 (FIG. 7), the posture of the cutting edge 51 may be adjusted so that the angle AH1 becomes smaller and the angle AH2 becomes larger.

  In the second usage, the sliding direction of the cutting edge 51u is a direction DB opposite to the direction DA. Therefore, the blade tip 51u is pushed by the shank 52 on the upper surface SF1 from the position N1 to the position N4. In order to easily generate the crack line CL1 (FIG. 7), the posture of the cutting edge 51 may be adjusted so that the angle AH1 becomes larger and the angle AH2 becomes smaller, contrary to the above.

Embodiment 3
Referring to FIGS. 16 and 17, in the present embodiment, cutting instrument 50v is used instead of cutting instrument 50 (FIG. 12). The cutting tool 50v has a cutting edge 51v instead of the cutting edge 51 (FIGS. 12 and 13). A conical surface SC having an apex as the projection PP is provided on the blade edge 51v.

  Next, how to use the cutting tool 50v when forming the trench lines TL1 to TL3 (FIG. 9) will be described. First, the projection PP on the cutting edge 51v (FIG. 16) is pressed against the upper surface SF1 at the position N1 (FIG. 4). Next, the pressed cutting edge 51 v is slid on the upper surface SF 1 of the glass substrate 4. In FIG. 16, the direction DA corresponds to the direction in which the axial direction AX extending from the cutting edge 51v is projected onto the upper surface SF1. Therefore, the cutting edge 51v is dragged by the shank 52 on the upper surface SF1. In order to facilitate the generation of the crack line CL1 (FIG. 7), the angle between the conical surface SC and the upper surface SF1 is smaller than the opposite side (left side in FIG. 16) of the direction DA, as shown in FIG. , On the side of the direction DA (right side in FIG. 16).

Fourth Preferred Embodiment
Referring to FIGS. 18 and 19, in the present embodiment, not only the sliding speed of cutting edge 51 but also the load that cutting edge 51 applies to glass substrate 4 in forming trench line TL1 and forming trench line TL2. Is changed. Specifically, when trench line TL1 is formed by the sliding of cutting edge 51 at the first speed described above, in the present embodiment, the load of cutting edge 51 is smaller than in the other embodiments. Will be lowered. The load when forming the trench line TL2 by the sliding of the cutting edge 51 at the above-described second speed is the same as that in the other embodiments. Therefore, the load when forming the trench line TL1 is smaller than the load when forming the trench line TL2. As a result of such selection of load, the width of the trench line TL1 is smaller than the width of the trench line TL2. The depth of trench line TL1 is smaller than the depth of trench line TL2.

  Referring to FIGS. 20 and 21, in the step of forming trench line TL2, blade tip 51 slid in reaches position N3 on upper surface SF1 of glass substrate 4, as shown by arrow R1, as shown by position N3. The crack of the glass substrate 4 in the thickness direction DT is extended along the trench line TL2 from the position to the position N2. Thus, the crack line CL1 is formed. In the present embodiment, the crack line CL2 (FIGS. 5 and 7) is not formed unlike the first embodiment because the load of the cutting edge 51 at the time of formation of the trench line TL1 is reduced as described above. In other words, the crack line is formed along only the trench line TL2 out of the trench line TL1 and the trench line TL2.

  Referring to FIGS. 22 and 23, thereafter, for the same reason as in the first embodiment (FIGS. 8 and 9), the sliding of cutting edge 51 is continued from position N3 to position N4. Thereby, the trench line TL3 is formed. The load when forming the trench line TL3 may be the same as the load when forming the trench line TL2. Next, the cutting edge 51 is separated from the glass substrate 4 at the position N4. Thereby, the sliding process of the blade edge 51 from the position N1 to the position N4 via the position N2 and the position N3 in order is completed.

  Next, the glass substrate 4 is divided along the crack line CL1 (in other words, the trench line TL2) and the trench line TL1. That is, a so-called break process is performed. The breaking step can be performed by applying an external force to the glass substrate 4. For example, by pressing a stress applying member (for example, a member called "break bar") on lower surface SF2 toward crack line CL1 (FIG. 23) on upper surface SF1 of glass substrate 4, the crack of crack line CL1 Is applied to the glass substrate 4 so as to open. The stress application causes the crack to extend along the trench line TL1 from the position N2 to the position N1. Therefore, the position where the glass substrate 4 is divided is further defined by the trench line TL1 in addition to the crack line CL1 (in other words, the trench line TL2).

  The configuration other than the above is substantially the same as the configuration of the other embodiments described above, so the same or corresponding elements have the same reference characters allotted, and description thereof will not be repeated.

  According to the present embodiment, the load of the cutting edge 51 when forming the trench line TL1 is further reduced. Thus, the wear of the cutting edge 51 can be suppressed.

  Although the case where the upper surface SF1 of the glass substrate 4 is flat has been described in the above embodiments, the upper surface SF1 may be curved. Although the trench lines TL1 to TL3 are illustrated as being linear, the trench lines TL1 to TL3 may be curved. In addition, since the sliding of the cutting edge 51 on the upper surface SF1 of the glass substrate 4 is performed by the relative movement between the glass substrate 4 and the cutting edge 51, the movement of at least one of the glass substrate 4 and the cutting edge 51 Can be implemented. 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, silicon, a compound semiconductor, sapphire or quartz.

4 Glass substrate (brittle substrate)
50, 50u, 50v Cutting tool 51, 51u, 51v Cutting edge CL1, CL2 Crack line (first and second crack line)
N1 to N4 position (first to fourth positions)
SF1 upper surface (one side)
TL1 to TL3 trench lines (first to third trench lines)

Claims (8)

The groove shape is formed by causing the plastic deformation on the one surface by sliding the cutting edge at a first speed from the first position to the second position on one surface of the brittle substrate. Forming the first trench line, and the step of forming the first trench line is continuously performed in the direction in which the brittle substrate intersects the first trench line below the first trench line. A crackless state which is a continuous state is performed to obtain a third state from the second position on the one surface of the brittle substrate after the step of forming the first trench line. By causing the cutting edge to further slide at a second speed lower than the first speed to a position, thereby generating plastic deformation on the one surface, a second torque having a groove shape is obtained. Forming the second trench line, the step of forming the second trench line is continuously connected in the direction crossing the second trench line with the brittle substrate below the second trench line The crackless state which is a state is performed, and the blade edge slid further in the step of forming the second trench line reaches the third position, thereby the third position from the third position. Forming a first crack line by extending a crack in the brittle substrate along a second trench line, the brittle substrate below the second trench line by the first crack line Is broken in the direction crossing the second trench line, and Forming a second crack line by extending the crack of the brittle substrate along the first trench line from the second position, when the lock line reaches the second position; The brittle substrate is broken continuously in the direction crossing the first trench line below the first trench line by the second crack line, and the first crack line and the first crack line are further broken. A method for dividing a brittle substrate, comprising the step of dividing the brittle substrate along a second crack line.   Prior to the step of forming the first trench line, the first position on the one surface of the brittle substrate is obtained by bringing the cutting edge located away from the brittle substrate closer to the brittle substrate. The method for dividing a brittle substrate according to claim 1, further comprising the step of bringing the cutting edge into contact with the brittle substrate, wherein the first position is separated from an edge of the one surface of the brittle substrate.   The method for dividing a brittle substrate according to claim 1, wherein the third position is apart from an edge of the one surface of the brittle substrate.   After the step of forming the first crack line, by further sliding the cutting edge at the second speed from the third position to the fourth position on the one surface of the brittle substrate, The method further includes the step of forming a third trench line having a groove shape by causing plastic deformation on the one surface, and the step of forming the third trench line includes the step of forming the third trench line. The crackless state according to any one of claims 1 to 3, wherein a crackless state is obtained, which is a state in which the brittle substrate is continuously connected in the direction intersecting with the third trench line below. How to cut brittle substrate.   After the step of forming the third trench line, the method further comprises the step of separating the cutting edge from the brittle substrate at the fourth position on the one surface of the brittle substrate, wherein the fourth position is the brittleness The method for dividing a brittle substrate according to claim 4, which is apart from the edge of the one surface of the substrate.   The distance by which the cutting edge slides between the second position and the fourth position is smaller than the distance by which the cutting edge slides between the first position and the second position. A method of dividing a brittle substrate according to claim 4 or 5.   The method for dividing a brittle substrate according to any one of claims 4 to 6, wherein a distance in which the cutting edge slides between the second position and the fourth position is 2 mm or more.   The method for dividing a brittle substrate according to any one of claims 1 to 7, wherein the second velocity is less than 25 mm / sec.