JP5627201B2 - Cleaving method of brittle material substrate - Google Patents

Description

  The present invention relates to a method of cleaving a brittle material substrate such as a glass substrate or a ceramic substrate by laser beam irradiation.

  Conventionally, as a method for cleaving a brittle material substrate such as a glass substrate or a ceramic substrate, the surface of the brittle material substrate is rolled while pressing a cutter wheel or the like, and cracks in a direction substantially perpendicular to the surface of the brittle material substrate ( (Hereinafter referred to as “vertical cracks”), and then a mechanical pressing force is applied to the substrate in the vertical direction so that the vertical crack propagates in the thickness direction of the substrate to cleave the substrate. It was.

  However, usually, when a vertical crack of a brittle material substrate is formed using a cutter wheel, small fragments called cullet are generated, and the cullet sometimes scratches the surface of the brittle material substrate. In addition, microcracks are easily generated at the edge of the brittle material substrate after cleaving, and the brittle material substrate may be cracked due to the microcracks. For this reason, usually, after cleaving, the edge of the brittle material substrate is polished and washed to remove microcracks, cullet and the like.

On the other hand, in recent years, a method in which a brittle material substrate is heated below the melting temperature using a CO ₂ laser beam and thereby a tensile stress is locally generated by the thermal stress generated in the brittle material substrate to form a vertical crack has recently been developed. Various studies and developments have been made. Since the cleaving method using this laser beam is non-contact processing, the occurrence of potential defects such as cullet and microcracks can be suppressed. However, even with this cleaving method using a laser beam, the vertical crack does not reach the entire thickness direction of the substrate and normally stops at the surface portion, so it is still necessary to apply the external force to propagate the vertical crack in the thickness direction of the substrate. Met. For this reason, the end faces of the vertical cracks may be pressed to cause microcracks, cullet, and the like.

  Therefore, in Patent Document 1, for example, an initial crack is formed on the side surface of the glass substrate, the cleavage line is preheated with a linear heater, and the crack is cracked by partially cooling the periphery of the progressing crack with a cooling mechanism such as an air nozzle. A technology to further advance the process has been proposed.

  In Patent Document 2, after forming an initial crack by simultaneously irradiating at least two points with a laser beam, the brittle material substrate is formed by moving the initial crack in the direction of the planned cutting line by moving along the planned cutting line. A method of cleaving has been proposed.

JP 2000-281375 A Japanese Unexamined Patent Publication No. 7-328781

  However, in the proposed technique of Patent Document 1, since an initial crack is formed on the side surface of the glass substrate, an initial crack having a predetermined length (depth) is formed in the direction of the planned cutting line (the depth direction when viewed from the substrate side surface). Difficult to do. In addition, a mechanism for fixing and supporting a force at the terminal part of the planned cutting line in the direction to open the split section and a mechanism for moving a sensor for detecting the progressing crack position, etc. are substantially required. The preparation work takes time and the apparatus becomes large. Further, since all the lines of the planned cutting line are heated by the heater wires arranged along the planned cutting line, the power consumption is increased as compared with the case of partial heating.

  In addition, the proposed technique of Patent Document 2 requires a plurality of laser oscillators and an optical axis changing unit, which may increase the complexity and size of the apparatus. Further, when an initial crack is formed by irradiation with a plurality of laser beams, it is difficult to adjust the laser output, the irradiation position, and the like, and the accuracy of the initial crack formation position may not be improved.

  The present invention has been made in view of such conventional problems, and the object of the present invention is to minimize the occurrence of microcracks, cullet, and the like without increasing the size and complexity of the apparatus. However, the object is to provide a method of cleaving a brittle material substrate.

  Another object of the present invention is to provide a method of cleaving one substrate of a laminated substrate that has been bonded, in which the cleaved substrate portion can be easily separated and removed.

  A brittle material substrate cleaving method according to a first invention that achieves the above object is a method of cleaving a brittle material substrate by irradiating it with a laser beam, the cleaving start end of a cleaved planned line on one surface of the substrate. A step of forming an initial crack with a cutter, and pressing a portion of the substrate opposite to the surface on which the initial crack is formed, facing the initial crack, and causing the initial crack to propagate in the thickness direction of the substrate. The step of forming an initial through crack reaching the opposite side surface and irradiating a laser beam from the initial through crack while moving relatively along the planned cutting line, and heating the substrate below the melting temperature, thereby the substrate And a step of causing the initial through crack to propagate along the planned cutting line due to the thermal stress generated in the step.

The cleaving method according to the second invention is a method of cleaving a brittle material substrate by irradiating it with a laser beam, and forming an initial crack with a cutter at a cleaving start end of a cleaving line on one side of the substrate. Irradiating a laser beam relative to the initial crack from the initial crack while moving relative to the initial crack to heat the substrate at a temperature lower than the melting temperature, thereby causing the initial crack to be caused by the thermal stress generated in the substrate. A step of forming along the planned cutting line to form an initial progress crack, and pressing a portion of the substrate opposite to the surface on which the initial progress crack is formed, facing the initial progress crack, and the initial progress crack. a step of initial penetration crack leading to the opposite side by progress in the thickness direction of the substrate, irradiation while relatively moving the laser beam from the initial through-crack along the expected splitting line To, heating the substrate at below the melting temperature, thereby the thermal stress generated in the substrate, and having a step to advance along the initial penetrating cracks the expected splitting line.

A cleaving method according to a third aspect of the present invention is a method of cleaving one brittle material substrate of a laminated substrate in which two brittle material substrates are bonded together, and starting cleaving of a cleaved planned line of the first brittle material substrate forming an initial crack with a cutter on the end of the second brittle material substrate, the initial crack with a portion facing the pressing, the initial crack first brittle material by progress in the thickness direction of the first brittle material substrate An initial through-crack reaching the opposite side of the substrate, and irradiating while moving the laser beam along the planned cutting line from the initial through-crack to heat the first brittle material substrate below the melting temperature, And a step of causing the initial through crack to propagate along the planned cutting line due to the thermal stress generated in the first brittle material substrate.

  A cleaving method according to a fourth aspect of the present invention is a method of cleaving one brittle material substrate of a laminated substrate in which two brittle material substrates are bonded, and starting cleaving of a cleaved planned line of the first brittle material substrate. A step of forming an initial crack with a cutter at the end, and irradiation with a laser beam being relatively moved from the initial crack along the planned cutting line to heat the first brittle material substrate below the melting temperature, thereby A step of causing the initial crack to propagate along the planned cutting line by a thermal stress generated in the first brittle material substrate; and a portion of the second brittle material substrate facing the initial progress crack. Pressing the initial progress crack in the thickness direction of the first brittle material substrate to form an initial through crack reaching the opposite side surface of the first brittle material substrate, and along the planned cutting line from the initial through crack Laser Bee The first brittle material substrate is heated at a temperature lower than the melting temperature, and the initial through-crack propagates along the planned cutting line due to the thermal stress generated in the first brittle material substrate. It is characterized by having.

  In the cleaving method for a brittle material substrate according to the present invention, the initial crack is a crack penetrating in the thickness direction of the substrate, and this initial through crack is propagated along the planned cutting line by laser beam irradiation. It is possible to minimize the occurrence of microcracks, cullet, etc. without incurring the increase in the size.

  Further, in the method of the present invention for cleaving one brittle material substrate of a laminated substrate obtained by bonding two brittle material substrates, in addition to the above effects, the second brittle material is formed when an initial through crack is formed. By pressing a portion of the substrate facing the initial crack, the first brittle material substrate and the second brittle material substrate are bent, the end faces of the initial through crack are adhered to each other, and the end portion of the first brittle material substrate is cleaved. The sticking between the removed portion and the second brittle material substrate is easily eliminated.

  In addition, according to the method in which the initial crack formed by the cutter is made slight and the initial crack is propagated to a predetermined length by laser beam irradiation, generation of microcracks and cullet can be further suppressed.

It is process drawing which shows an example of the cutting method of the brittle material board | substrate which concerns on this invention. It is process drawing which shows the other formation method of an initial stage crack. It is process drawing which shows an example of the cutting method of the laminated substrate which concerns on this invention.

  Hereinafter, although the cutting method of the brittle material substrate according to the present invention will be described in more detail, the present invention is not limited to these embodiments.

  FIG. 1 is a process diagram showing an embodiment of a brittle material substrate cleaving method according to the present invention. FIG. 1 is a process diagram in the case where the glass substrate 1 as a brittle material substrate is cleaved by a cleaving planned line 11. As shown in FIG. 1A, first, an initial crack 31 is formed by the cutter wheel 2 at the cleaving start end As of the surface 10 a of the glass substrate 1. The length and depth of the initial crack 31 are not particularly limited, but usually, the length of the initial crack 31 is preferably in the range of 1 to 30 mm, more preferably in the range of several mm. The depth of the initial crack 31 is preferably 10% or more of the substrate thickness.

  Next, as shown in FIG. 2B, the part facing the initial crack 31 on the back surface 10 b of the glass substrate 1 is pressed by the break roller 4 in the direction of the front surface 10 a. Thereby, the initial crack 31 becomes the initial penetration crack 32 which progresses in the thickness direction of the glass substrate 1 and reaches the back surface 10b.

  Next, as shown in FIG. 5C, the laser beam 51 having an elliptical shape is irradiated from the initial through-crack 32 of the glass substrate 1 along the planned cutting line 11 and cooled near the rear end of the laser beam irradiation region. Cooling water 61 as a medium is sprayed from the cooling nozzle 60. By irradiating the glass substrate 1 with the laser beam 51, the glass substrate 1 is heated below the melting temperature in the thickness direction, and the glass substrate 1 tries to thermally expand, but cannot expand due to local heating, and the irradiation point is the center. Compressive stress is generated. Then, immediately after the heating, the cooling water 61 is sprayed on the surface of the glass substrate 1 and cooled, whereby a tensile stress is generated. Due to the action of the tensile stress, the crack throughout the thickness direction of the glass substrate 1 starts from the initial through crack 32 as a starting point. Then, by moving the laser beam 51 along the planned cutting line 11, the crack 33 throughout the thickness direction of the substrate continuously develops along the moving direction of the laser beam 51, and the glass substrate 1 is cut along the planned cutting line 11. It is cleaved. In this embodiment, the glass substrate 1 is fixed and the laser beam 51 is moved. However, the glass substrate 1 is moved and the laser beam 51 is fixed, or both the glass substrate 1 and the laser beam 51 are moved. Of course you don't mind. The crack 33 starting from the initial through-crack 32 can be developed by natural air cooling without spraying the cooling water 61, but the crack 33 is more forcibly cooled by spraying the cooling water 61. This is desirable because it can be quickly and reliably developed.

The laser beam 51 used here is not particularly limited, and may be determined as appropriate based on the material and thickness of the substrate. When the brittle material substrate is a glass substrate, a laser beam with a wavelength of 9 to 11 μm is preferable because of the large absorption on the substrate surface. An example of such a laser beam is a CO ₂ laser. The irradiation shape of the laser beam 51 onto the glass substrate 1 is preferably an elliptical shape that is long in the relative movement direction of the laser beam 51.

  Distilled water is preferable as the water ejected from the cooling nozzle 60. However, an additive such as a surfactant may be added to water within a range that does not adversely affect the use of the brittle material substrate after cleaving. The amount of cooling water is usually in the range of 1 to 2 ml / min. The cooling of the glass substrate 1 with water is preferably a so-called water jet method in which water is injected together with gas (usually air) from the viewpoint of rapidly cooling the glass substrate 1 heated by the laser beam 41. The cooling region with cooling water is preferably circular or elliptical with a diameter of about 1 to 5 mm. The cooling region is preferably formed behind the heating region in the relative movement direction by the laser beam 51 and in the vicinity of the rear end of the heating region.

  The relative moving speed of the laser beam 51 may be determined as appropriate based on the laser beam output value, the irradiation area, the thickness of the brittle material substrate 1, etc., but is usually preferably in the range of 1 to several hundred mm / sec.

  The cleaving method of the present invention can be used for cleaving conventionally known brittle material substrates such as ceramic substrates, single crystal silicon substrates, and sapphire substrates in addition to the glass substrate described above, and is suitable for the panel manufacturing field such as a liquid crystal display. Can be used for

  In the cleaving method described above, since the crack 33 is propagated by laser beam irradiation starting from the initial through crack 32 slightly formed at the end of the glass substrate 1, it is possible to effectively suppress the occurrence of cullet and microcracks. it can. Further, in order to further suppress the occurrence of cullet, microcracks, etc., it is recommended to suppress the cracks formed by the cutter wheel 2 and to form the remaining length necessary for the initial cracks by laser beam irradiation. Such an initial crack formation method is shown in FIG.

  In FIG. 2 (a-1), the cutter wheel 2 forms a crack 31 a at the cleaving start end As of the surface 10 a of the glass substrate 1. The crack 31a has only to have a length that allows the crack to develop by laser beam irradiation, and may be a point crack (several tens of μm), for example. Thereby, the cullet, micro crack, etc. which generate | occur | produce by use of the cutter wheel 2 can be suppressed to the minimum.

  Next, as shown in FIG. 4A-2, the laser beam 51 is irradiated along the planned cutting line 11 from the crack 31a, and the cooling water 61 is supplied from the cooling nozzle 60 near the rear end of the laser beam irradiation region. It sprays and the crack 31a is extended along the cutting projected line 11, and it is set as the initial stage crack 31 of predetermined length. Since the progress of the crack 31a is performed in a non-contact manner with the glass substrate 1, no cullet or microcrack is generated. Since the process after the process of forming the initial through crack 32 shown in FIG. 4B is the same as the cleaving method shown in FIG. 1, the description thereof is omitted here. The propagation mechanism of the crack 31a by laser beam irradiation is the same as the propagation mechanism of the crack 33 starting from the initial through crack 32 described above.

  Next, a method for cleaving one brittle material substrate of a laminated substrate obtained by bonding two brittle material substrates together will be described. FIG. 3 shows a method of cleaving a part of the glass substrate 7 of the laminated substrate P in which the glass substrate (first brittle material substrate) 7 and the glass substrate (second brittle material substrate) 8 are bonded together by the sealant S. The figure is shown. As shown in FIG. 1A, first, an initial crack 31 is formed by rolling the cutter wheel 2 on the surface end of the glass substrate 7 while being pressed. The length and depth of the initial crack 31 are the same as those in the above embodiment.

  Next, as shown in FIG. 2B, the part facing the initial crack 31 on the back surface side of the glass substrate 8 is pressed toward the glass substrate 7 by the break roller 4. As a result, the laminated substrate P is bent so as to be convex upward, and the initial crack 31 propagates in the entire thickness direction of the glass substrate 7 to become an initial through crack 32. At the same time, the sticking between the end faces of the initial through crack 32 and the sticking between the cleaving removal portion 71 and the glass substrate 8 at the end of the glass substrate 7 are eliminated, and the cleaving removal portion 71 of the glass substrate 7 is easily separated. You can do it.

  Next, as shown in FIG. 5C, the laser beam 51 having an elliptical shape is irradiated from the initial through-crack 32 of the glass substrate 7 along the planned cutting line 11 and cooled near the rear end of the laser beam irradiation region. Cooling water 61 as a medium is sprayed from the cooling nozzle 60, and the crack 33 extending in the entire thickness direction of the glass substrate 7 starts from the initial through crack 32. By moving the laser beam 51 along the planned cutting line 11, the crack 33 throughout the thickness direction of the glass substrate 7 continuously develops along the moving direction of the laser beam 51, and the glass substrate 7 moves along the planned cutting line 11. Cleaved at. Then, as shown in FIG. 4D, the cleaving removal portion 71 is separated and removed from the laminated substrate P. In this embodiment, the laminated substrate P is fixed and the laser beam 51 is moved. However, the laminated substrate P is moved and the laser beam 51 is fixed, or both the laminated substrate P and the laser beam 51 are moved. Of course you don't mind. The crack 33 starting from the initial through-crack 32 can be developed by natural air cooling without spraying the cooling water 61, but the crack 33 is more forcibly cooled by spraying the cooling water 61. This is desirable because it can be quickly and reliably developed.

  Further, similarly to the above embodiment, from the viewpoint of further suppressing the occurrence of cullet, microcracks, and the like by the cutter wheel 2, the cracks formed by the cutter wheel 2 are suppressed to a short length, and the remaining length necessary for the initial crack is irradiated with the laser beam. You may form by.

  Such a method for cleaving a laminated substrate covers, for example, when two glass substrates of a liquid crystal display panel are bonded and a terminal electrode is formed on the inner surface of one of the glass substrates. This is preferably used when the terminal electrode is exposed by cutting and removing the exposed portion.

  In the method of cleaving the brittle material substrate of the present invention, the initial crack formed by the cutter is a crack penetrating in the thickness direction of the substrate, and this initial through crack is propagated along the planned cutting line by laser beam irradiation. This is useful because it can minimize the generation of microcracks and cullet without increasing the size and complexity.

  In addition to the above effect, the method of the present invention for cleaving one brittle material substrate of a laminated substrate obtained by laminating two brittle material substrates further includes the second brittle material when forming an initial through crack. By pressing the part of the substrate that faces the initial crack, the sticking between the end faces of the initial through crack and the sticking of the glass substrate with the cleaving removal part of the edge of the glass substrate is eliminated, and the glass substrate is cleaved. Separation of the removed portion is facilitated and useful.

1 Glass substrate (brittle material substrate)
2 Cutter wheel (cutter)
4 Break roller 7 Glass substrate (first brittle material substrate)
8 Glass substrate (second brittle material substrate)
P Laminated substrate 11 Cut line 31 Initial crack 32 Initial through crack 33 Crack 51 Laser beam 61 Cooling water

Claims (4)

A method of cleaving a brittle material substrate by laser beam irradiation,
A step of forming an initial crack with a cutter at a cleaving start end of a cleaving line on one side of the substrate, and pressing a portion of the substrate opposite to the initial crack on a side surface opposite to the surface on which the initial crack is formed. A step of causing the initial crack to propagate in the thickness direction of the substrate and an initial through crack reaching the opposite side surface, and irradiating while moving the laser beam from the initial through crack along the cleaved line, A method of cleaving a brittle material substrate, comprising: heating the substrate at a temperature lower than a melting temperature, and causing an initial through crack to propagate along the planned fracture line by thermal stress generated in the substrate. A method of cleaving a brittle material substrate by laser beam irradiation,
A step of forming an initial crack with a cutter at a cleaving start end of a cleaving line on one side of the substrate, and irradiating the substrate while moving the laser beam relatively along the cleaving line from the initial crack; Heating at a temperature lower than the melting temperature, thereby causing the initial crack to propagate along the planned cutting line by the thermal stress generated in the substrate, and forming the initial progress crack in the substrate face opposite sides, wherein pressing the initial progress crack a portion facing the steps of an initial penetration crack leading to the opposite side by the progress of the initial progress crack in the thickness direction of the substrate, from the initial through-crack wherein with radiation along the expected splitting line by relatively moving the laser beam, heating the substrate at below the melting temperature, thereby the thermal stress generated in the substrate, wherein the initial penetrating crack Brittle material breaking method of the substrate; and a step of developing along a cross-sectional plan line.
A method of cleaving one brittle material substrate of a laminated substrate obtained by bonding two brittle material substrates,
A step of forming an initial crack with a cutter at the cutting start end of the cutting line of the first brittle material substrate, a portion of the second brittle material substrate facing the initial crack is pressed, and the initial crack is made into the first brittleness A process of developing in the thickness direction of the material substrate to form an initial through crack reaching the opposite side surface of the first brittle material substrate, and irradiating while moving the laser beam from the initial through crack along the cutting line, A step of heating the first brittle material substrate at a temperature lower than the melting temperature, thereby causing the initial through crack to propagate along the planned cutting line by the thermal stress generated in the first brittle material substrate. Material substrate cleaving method. A method of cleaving one brittle material substrate of a laminated substrate obtained by bonding two brittle material substrates,
A process of forming an initial crack with a cutter at a cleave start line of the first brittle material substrate, and a laser beam is irradiated from the initial crack while moving relatively along the planned cut line, thereby causing the first brittleness A step of heating the material substrate at a temperature lower than the melting temperature, thereby causing the initial crack to propagate along the planned cutting line by the thermal stress generated in the first brittle material substrate; and a second brittleness Pressing a portion of the material substrate facing the initial progress crack, and developing the initial progress crack in the thickness direction of the first brittle material substrate to form an initial through crack reaching the opposite side surface of the first brittle material substrate; The first brittle material substrate is irradiated with the laser beam being relatively moved from the initial through crack along the planned cutting line to heat the first brittle material substrate at a temperature lower than the melting temperature, thereby causing the thermal stress generated in the first brittle material substrate. It, breaking method of the brittle material substrate, characterized in that a step to advance along the initial penetrating cracks the expected splitting line.