JP2012218963A - Laser processing apparatus for glass substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser processing apparatus for a glass substrate, which can shorten the processing time taken to divide the glass substrate and prevent waste formation.SOLUTION: From a laser light source, pulsed laser light of a wavelength of 250-400 nm is emitted, and the laser light is shaped into first laser beams 10 whose length along a prescribed cutting line is short and is allowed to strike the glass substrate at a first interval whose distance along the prescribed cutting line is long. Then, the laser light is shaped into second laser beams 20 whose length along the prescribed cutting line is long and is allowed to strike the glass substrate at a second interval whose distance along the prescribed cutting line is short. Here, the first and second laser beams are allowed to strike the glass substrate so that the non-struck positions between the first laser beams 10 coincide with the positions struck by the second laser beams 20.

Description

  The present invention relates to a laser processing apparatus for a glass substrate suitable for dicing a surface-reinforced glass substrate.

  In manufacturing a liquid crystal display panel, exposure and development are repeated on a glass substrate to form a pattern composed of predetermined pixels and circuits. In this case, individual panels are manufactured by simultaneously forming patterns for a plurality of panels on a single glass substrate and then dividing the glass substrate. Conventionally, the division of the glass substrate is performed by mechanical dicing processing in which a planned cutting line is ground into a linear shape with a rotary blade (Patent Document 1).

JP 2007-229831 A

  However, in this mechanical dicing process, it is necessary to move the dicing blade along the planned cutting line at a low speed, and it takes a long processing time per glass substrate, and there is a problem that the manufacturing tact is poor. . In addition, the glass substrate is easily broken during the dicing process, the yield is low, and cutting waste is generated when cutting with the rotary blade. In particular, in the case of surface tempered glass, the above-mentioned problem becomes more remarkable.

  The present invention has been made in view of such problems, and provides a laser processing apparatus for a glass substrate capable of reducing the processing time for dividing the glass substrate and preventing the generation of dust. Objective.

A laser processing apparatus for a glass substrate according to the present invention includes a laser light source that emits a pulsed laser beam having a wavelength of 250 to 400 nm, an optical system that irradiates the glass substrate with the laser beam in a predetermined beam shape, and the optical system. And a driving device that moves the irradiation position of the laser light on the glass substrate along a planned cutting line by relatively moving the glass substrate and the glass substrate, and the irradiation position of the laser light is a point along the planned cutting line A control device for intermittently irradiating the glass substrate with the laser light so as to exist,
The controller irradiates the first laser beam having a short length along the planned cutting line at a first interval having a long distance along the planned cutting line, and has a long length along the planned cutting line. The second laser beam is irradiated at a second interval with a short distance along the planned cutting line so that the non-irradiation position between the first laser beams and the irradiation position of the second laser beam correspond to each other. And controlling the laser light source, the optical system, and the driving device.

  In the laser processing apparatus for a glass substrate according to the present invention, for example, the optical system may form the second laser by shaping the beam shape of laser light emitted from the laser light source so as to be elongated along the planned cutting line. It may have a cylindrical lens for obtaining a beam. By using a long and narrow beam along the planned cutting line, the processing speed of laser dicing is further improved.

  In addition, the optical system has the focal positions of the first and second laser beams in the thickness direction of the glass substrate, and the focal depth is shorter than the thickness of the glass substrate, preferably the glass It is preferable to set it to 1/100 or less of the thickness of the substrate. Thereby, the process trace by irradiation of a laser beam can be formed in the inside of a glass substrate. This reliably prevents the surface from being cracked by the laser beam irradiation.

  In addition, when this elongated beam-shaped laser beam is used, a camera that is disposed behind the moving direction of the laser beam with respect to the glass substrate and detects a processing trace caused by the irradiation of the previous laser beam, and the camera detects the laser beam. An adjustment unit for adjusting the irradiation position with respect to the direction perpendicular to the laser beam moving direction and adjusting the irradiation timing with respect to the subsequent irradiation of the laser beam on the basis of the position of the previous processed trace. It is preferable. Thereby, the position of the next shot of the laser beam (the longitudinal direction of the planned cutting line and the direction perpendicular thereto) can be adjusted based on the position of the processing mark by the previous laser shot.

  Furthermore, the laser processing apparatus for a glass substrate of the present invention is beneficial when applied to a surface tempered glass substrate. Since the surface tempered glass substrate has a hard surface property, the surface tempered glass substrate is further broken in mechanical dicing using a dicing blade, and even in laser dicing, if the focal position is the surface of the glass substrate, it is broken during processing. In the present invention, the focal positions of the first and second laser beams are set in the thickness direction of the surface tempered glass substrate and deeper than the surface tempered layer of the surface tempered glass substrate. Therefore, even a surface tempered glass substrate is prevented from being broken during processing.

  According to the present invention, a laser beam having a wavelength of 250 to 400 nm is used, and the first laser beam having a short beam shape along the planned cutting line is irradiated at a large first interval. Irregular cracking is prevented from occurring on the surface of the glass substrate by the laser beam irradiation. Thereafter, the second laser beam having a long beam shape along the planned cutting line is separated from the non-irradiation position between the first laser beams and the irradiation position of the second laser beam at a small second interval. Therefore, even when the second laser beam is irradiated, the surface of the glass substrate is prevented from breaking in an irregular direction. Therefore, according to the present invention, the glass substrate can be cleaved along the planned cutting line with high accuracy.

It is a perspective view which shows the laser processing apparatus of 1st Embodiment of this invention. It is a schematic diagram which similarly shows the processing process (1st process) only by the irradiation of the 1st laser beam. It is a schematic diagram which similarly shows the processing process (2nd process) by irradiation of the 2nd laser beam. It is a schematic diagram which shows the laser processing method of 1st Embodiment of this invention. It is a schematic diagram which shows the laser processing method of the modification of this invention. It is a schematic diagram which shows the laser processing method of 2nd Embodiment of this invention. It is a graph which shows the permeation | transmission characteristic of a surface strengthened glass substrate. It is a schematic diagram which shows the laser processing method of 3rd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings. FIG. 1 is a perspective view showing a laser processing apparatus for a glass substrate according to an embodiment of the present invention. On the stage 1, a glass substrate 2 such as a surface-reinforced glass substrate after exposure and development processing, which is a workpiece, is placed. A gate-shaped moving member 3 straddling the entire region in the width direction of the stage 1 is supported on the stage 1 so as to be capable of reciprocating in the direction of arrow a. The moving member 3 is provided with a support portion 4 that can reciprocate in the width direction (arrow b direction) of the stage 1, and a pulse laser oscillator 6 is supported on the support portion 4. An objective lens 5 is provided below the pulse laser oscillator 6 so that the pulse laser light from the pulse laser oscillator 6 is focused on a glass substrate.

  In this laser processing apparatus, a glass substrate 2 such as a surface tempered glass substrate is placed on a stage 1, and pulse laser light is intermittently emitted from a pulse laser oscillator 6 while the moving member 3 moves in the direction of arrow a. The glass substrate 2 is irradiated with pulsed laser light that is emitted and collected by the objective lens 5. When the moving member 3 moves in the direction of the arrow a, the processing traces by the laser beam are formed on the glass substrate 2 so as to be scattered on a straight line extending in the direction of the arrow a. The glass substrate 2 is cleaved starting from the processing mark by applying a bending stress at. The irradiation position of the pulse laser beam on the glass substrate 2 can be adjusted by moving the support portion 4 in the arrow b direction on the moving member 3. In addition, a plurality of objective lenses 5 having different focal lengths are attached to the support unit 4, and an optimum objective lens is selected from these objective lenses 5 according to the type of the glass substrate 2 to be processed. Laser processing can be performed.

  FIG. 2 is a schematic diagram showing the first step of this laser processing. The first laser beam 10, which is a pulse laser beam, has a wavelength of 250 to 400 nm, is focused on the inside of the glass substrate 2 in the thickness direction by an optical system including the objective lens 5, and has a depth of focus. The thickness is set to be shorter than the thickness of the glass substrate, and is preferably set to a range of 1/100 or less of the thickness of the glass substrate 2.

  In the first step shown in FIG. 2, the beam shape 11 of the first laser beam 10 is, for example, a square. The first laser beam 10 has a short length along the planned cutting line, and the interval between the irradiation positions is a first distance having a long distance along the planned cutting line. The first laser beam 10 is intermittently applied to the glass substrate 2 while moving along the planned cutting line while the support portion 4 is moving in the direction of arrow a. Then, the processing marks 12 are formed so as to be scattered along the planned cutting line inside the glass substrate 2 in the thickness direction.

  FIG. 3 is a schematic diagram showing a second step of laser processing according to the present embodiment. The second laser beam 20, which is a pulse laser beam, has a wavelength of 250 to 400 nm, is focused on the inside of the glass substrate 2 in the thickness direction by an optical system including the objective lens 5, and has a depth of focus. The thickness is set to be shorter than the thickness of the glass substrate, and is preferably set to a range of 1/100 or less of the thickness of the glass substrate 2.

  In the second step shown in FIG. 3, the beam shape 21 of the second laser beam 20 is, for example, an elongated slit shape or a rectangular shape. The second laser beam 20 has a long length along the planned cutting line, and the interval between the irradiation positions is a second distance having a short distance along the planned cutting line. The second laser beam 20 is intermittently applied to the glass substrate 2 while moving along the planned cutting line while the support portion 4 is moving in the direction of arrow a. Then, the processing marks 22 are formed so as to be scattered along the planned cutting line inside the glass substrate 2 in the thickness direction. The first laser beam 10 is irradiated at a first interval with a short length along the planned cutting line and a long distance along the planned cutting line, and the second laser beam 20 is along the planned cutting line. Irradiation is performed at a second interval having a long length and a long distance along the planned cutting line. This long or short criterion is relative to the first laser beam 10 and the second laser beam 20. It is a comparison. However, the interval between the first laser beams 10 needs to be sufficiently long so that no cracks or cracks occur on the surface of the glass substrate 2. The irradiation position of the second laser beam 20 corresponds to the non-irradiation position of the first laser beam 10 between the first laser beams 10. The irradiation regions of the laser beam 20 may overlap each other or may be slightly separated from each other. In the case of being separated, if the distance is too large, it becomes difficult to cleave when applying a stress to the glass substrate, so that the distance between the first and second laser beams 10 and 20 is not cleaved. It is necessary to appropriately determine in consideration of ease (low stress necessary for cleaving).

  In order to obtain the above-described elongated beam shape 21, a condensing lens made of a cylindrical lens may be provided in the optical system that guides the laser light from the pulse laser oscillator 6 to the glass substrate 2. By passing the laser light through the cylindrical lens, the beam shape of the laser light can be made into a horizontally long rectangular shape.

  The wavelength of the laser beam of the pulse laser beam 10 is 250 to 400 nm. FIG. 7 is a graph showing the transmission characteristics of the surface tempered glass, where the horizontal axis represents wavelength and the vertical axis represents the transmittance of laser light. In the case of laser light having a wavelength of 532 nm, the transmittance with respect to the glass substrate is high, that is, the energy absorption rate of the glass substrate is poor, and it is difficult to form a processing mark on the glass substrate. On the other hand, energy absorption starts near the i-line (wavelength 365 nm) of a mercury lamp, and a processing mark can be formed. Further, by using a laser beam having a wavelength of 266 nm, an extremely high energy absorption rate can be obtained. Therefore, in this invention, a process trace is formed in a glass substrate in the wavelength range of 250-400 nm.

  Next, the operation of this embodiment will be described. First, as shown in FIG. 2, the first laser beam 10 having a rectangular (square) beam shape is moved while moving the irradiation position of the pulsed laser light in the direction of the white arrow relative to the glass substrate. The glass substrate is irradiated intermittently at a large first interval to form a processing mark 12. The interval between the processing marks 12 is a relatively large first interval. For this reason, the glass substrate 2 is not randomly cracked from the irradiation position by the shot by the first laser beam 10. Thereafter, as shown in FIG. 3, the second laser beam 20 having an elongated beam shape is moved in the direction of the white arrow and is made to correspond to the non-irradiated region of the first laser beam 10 between the processing marks 12. Then, the processing marks 22 are formed by intermittent irradiation at a small second interval. As a result, as shown in FIG. 4, the processing marks 12 and 22 are alternately arranged in a line, and the processing marks 12 and 22 are formed on the planned cutting line. In this case, since the first laser beam 10 and the second laser beam 20 are moved on a straight line to be cut, the glass substrate 2 may be broken by the irradiation of the second laser beam 20. However, it is not broken in an irregular and messy direction, and it is cleaved on a predetermined planned cutting line. If the glass substrate 2 is not broken even by irradiation with the second laser beam 20, the glass starts from the processing marks 12 and 22 formed on one straight line by applying stress to the glass substrate by hand. The substrate can be cleaved.

For example, when laser light having a wavelength of 532 nm is used, the pulse width is about 7 nsec, the irradiation energy density is 25 J / cm ² , and laser light is irradiated inside the surface-reinforced glass substrate, cracks develop in the glass substrate. The entire glass substrate is broken randomly. In contrast, when laser light having a wavelength of 355 nm is used, the pulse width is about 7 nsec, the irradiation energy density is 10 J / cm ² , and the laser light is irradiated inside the surface-reinforced glass substrate, the inside of the glass substrate is When a processing mark is formed and bending stress is applied to the glass substrate by hand, it can be cleaved neatly by a straight cutting line based on the processing mark.

  The focal positions of the first and second laser beams 10 and 20 may be the surface of the glass substrate. When laser beams are irradiated at positions close to each other, that is, when the interval between the irradiation positions of the laser beam 10 shown in FIG. 2 is short, a crack develops in a messy direction due to the laser beam irradiation. Irregular cracks will occur. However, in the present embodiment, the irradiation position of the first laser beam 10 is set at a sufficiently large interval. Therefore, even when the focal position is the surface of the glass substrate, the irradiation of the first laser beam 10 is performed. Will not cause irregular cracks.

  However, by setting the focal positions of the first and second laser beams to the inside of the glass substrate 2, it is possible to more reliably prevent the glass substrate from being cracked. That is, the focal position of the laser beam is set in the thickness direction of the glass substrate 2, and the depth of focus is set shorter than the thickness of the glass substrate 2, preferably 1/100 or less of the thickness of the glass substrate 2. As a result, even in the case of a surface tempered glass substrate, it is possible to concentrate the energy of the laser beam in the interior of the surface tempered glass substrate while avoiding the modified portion. When the glass substrate 2 is a surface tempered glass substrate, if the laser beam is focused not on the inside of the glass substrate 2 but on the modified portion of the surface of the surface tempered glass substrate, the glass substrate 2 is messy. Cracks are generated and easily broken randomly. Further, when the focal depth of the laser beam is equal to or greater than the thickness of the glass substrate, the laser beam reaches the back surface of the glass substrate 2 and is broken by a crack. For this reason, the focal depth of the laser light is shorter than the thickness of the glass substrate, and preferably within a range of 1/100 or less of the thickness of the glass substrate.

  Of course, the focal positions of the first laser beam 10 and the second laser beam 20 may be different in the thickness direction of the glass substrate 2. For example, a pulse laser beam having a wavelength of 266 nm is used as the first laser beam 10, a pulse laser beam having a wavelength of 355 nm is used as the second laser beam 20, and the focal position thereof is set to the first laser beam 10. It can be set so that is shallower and the second laser beam 20 is deeper. As described above, the focal positions of the first laser beam 10 and the second laser beam 20 are made different in the depth direction of the glass substrate, so that the position where the energy is concentrated differs in the depth direction of the glass substrate 2. , It is possible to prevent the areas where energy is concentrated from overlapping.

  As shown in FIGS. 2 and 3, the scanning and intermittent irradiation of the first laser beam 10 and the scanning and intermittent irradiation of the second laser beam 20 are both performed in the same direction (in FIG. (Shown by a blank arrow) may be performed by moving relative to the glass substrate 2, or when the moving member 3 and the objective lens 5 are reciprocated, the first laser beam 10 is irradiated in the forward path. The second laser beam 20 may be irradiated on the return path. Further, the beam shapes of the first and second laser beams 10 and 20 are not limited to squares and rectangles, respectively, as in the above-described embodiment, and various shapes such as circles and ellipses can be used. .

  Furthermore, as shown in FIG. 5, a recess can be formed instead of a processing mark by the first laser beam. As shown in FIG. 5B, the glass substrate 2 of FIG. 5A is irradiated with the first laser beam 10 having a short length along the planned cutting line at a wide interval, so that the glass substrate 2 of FIG. Melt the surface. As a result, a recess 28 that does not penetrate the glass substrate 2 is formed on the surface of the glass substrate 2. Thereafter, as shown in FIG. 5C, the second laser beam 20 having a long length along the planned cutting line is irradiated between the recesses 28 so as to include a part of the recesses 28. Thereby, a processing mark is formed so as to communicate between the recesses 28. In this way, even if the first laser beam 10 gives a large energy for forming a recess instead of a processing mark, the first laser beam 10 can be made as long as the distance between the first laser beams 10 is sufficiently wide. The irradiation with the laser beam 10 does not cause cracks in irregular directions. Although the glass substrate 2 may be broken by the irradiation of the second laser beam 20, in this case, since there is already an irradiated portion called the concave portion 28, the crack is not irregularly formed and the cutting line is not cut. Along the glass substrate 2, cracks occur.

  Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, the laser scanning is not performed by moving the pulse laser oscillator 6 and the objective lens 5 as in the embodiment shown in FIG. 1, but the glass substrate 2 is moved, and the pulse laser oscillator 6 and the objective lens 5 are Laser scanning is performed in a fixed state. As shown in FIG. 6, the laser beam 20 emitted from the fixedly installed pulse laser oscillator 6 is focused on the glass substrate 2 by the objective lens 5. The focal position of the laser light is set in the thickness direction of the glass substrate 2, and the focal depth is set shorter than the thickness of the glass substrate 2, preferably 1/100 or less of the thickness of the glass substrate 2.

  And the line illumination 32 is installed above the glass substrate 2 in the vicinity of the irradiation position of the laser beam 20 focused on the glass substrate by the objective lens, and the position facing the line illumination 32 across the glass substrate 2 A high-speed camera 31 is installed below the glass substrate 2. Thereby, the glass substrate 2 is irradiated with light 33 from the line illumination 32 from above to illuminate the processing trace 22, and the processing trace 22 is observed by the camera 31 from below the glass substrate 2. The line illumination 32 irradiates light 33 having a horizontally long beam shape flattened in the scanning direction of the laser light (longitudinal direction of the horizontally long processing mark 22). The light 33 from the line illumination 32 illuminates the horizontally long processing mark 22 and the camera 31 observes or photographs the processing mark 22, thereby detecting the position of the processing mark 22 formed by the previous shot by the laser beam 20. can do.

  Therefore, by adjusting the position of the next laser shot in accordance with the detection position of the processing mark 22, a long processing mark 22 can be formed on one straight line without deviating from the planned cutting line. .

  Thus, by observing the previous processing mark 22 with the camera 31 and adjusting the position of the next laser shot, the linearity of the position of the processing mark 22 can be improved, and the linear accuracy is increased. The accuracy of the cleaving position for the planned cutting line can be increased.

  Next, a third embodiment of the present invention will be described with reference to FIG. In the present embodiment, a microlens array 40 is used for irradiation with the first laser beam 10. In the microlens array 40, microlenses 41 are arranged in a line at a predetermined pitch (first interval), and only an arrangement position of the microlens 41 is provided by an aperture stop built in the microlens 41. The laser beam 10 can be irradiated toward the glass substrate 2.

  In the present embodiment, the glass substrate 2 is irradiated with the first laser beam 10 using the microlens array 40. Thereby, the glass substrate 2 can be simultaneously irradiated with the plurality of first laser beams 10 from the plurality of microlenses 41 provided in the microlens array 40. Thereafter, the microlens array 40 is moved relative to the glass substrate 2 in the direction indicated by the arrow in FIG. A processing mark 12 is formed on the surface. Next, as a second step, the second laser beam 20 is formed by a cylindrical lens as in the first and second embodiments, and is irradiated between the processing marks 12. Thereby, this embodiment also has the same effect as the first and second embodiments, and in this embodiment, there is an effect that a processing mark can be formed more quickly.

1: stage 2: glass substrate 3: moving member 4: support member 5: objective lens 6: pulse laser oscillator 10: first laser beam 20: second laser beam 11, 21: beam shape 12, 22: processing trace 28: Recess 31: Camera 32: Line illumination 40: Micro lens array 41: Micro lens

Claims (5)

A laser light source that emits a pulse laser beam having a wavelength of 250 to 400 nm, an optical system that irradiates the glass substrate with the laser beam in a predetermined beam shape, and the optical system and the glass substrate are relatively moved. A driving device for moving the irradiation position of the laser light on the glass substrate along a planned cutting line; and intermittently the laser light so that the irradiation position of the laser light is scattered along the planned cutting line. A control device for irradiating the glass substrate,
The controller irradiates the first laser beam having a short length along the planned cutting line at a first interval having a long distance along the planned cutting line, and has a long length along the planned cutting line. The second laser beam is irradiated at a second interval with a short distance along the planned cutting line so that the non-irradiation position between the first laser beams and the irradiation position of the second laser beam correspond to each other. The glass substrate laser processing apparatus characterized by controlling the laser light source, the optical system, and the driving device. The optical system includes a cylindrical lens that obtains the second laser beam by shaping a beam shape of laser light emitted from the laser light source so as to be elongated along the planned cutting line. Item 2. A laser processing apparatus for a glass substrate according to Item 1. The optical system is characterized in that the focal positions of the first and second laser beams are set in the thickness direction of the glass substrate and the depth of focus is set shorter than the thickness of the glass substrate. The laser processing apparatus of the glass substrate of Claim 1 or 2. The laser beam is arranged behind the moving direction of the laser beam with respect to the glass substrate and detects a processing mark due to irradiation of the conventional laser beam, and the laser beam is based on the position of the previous processing mark detected by the camera. 3. The glass substrate laser according to claim 2, further comprising: an adjustment unit that adjusts the irradiation position in the direction perpendicular to the laser beam moving direction and adjusts the irradiation timing. Processing equipment. The glass substrate is a surface tempered glass substrate, and the optical system has a focal position of the first and second laser beams inside the thickness direction of the surface tempered glass substrate, and the surface tempered glass. The laser processing apparatus for a glass substrate according to any one of claims 1 to 4, wherein the laser processing apparatus is set at a position deeper than the surface reinforcing layer of the substrate.

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