JP2009255113A - Brittle material substrate processing apparatus and brittle material substrate cutting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a laser beam suitable for full cutting. <P>SOLUTION: A processing apparatus comprises a laser irradiator 10 for patterning a laser beam into an elongated shape having a scheduled processing line in the longitudinal direction and irradiating the scheduled processing line on a brittle material substrate with the patterned laser beam. A pair of Axicon lenses 12, 14 are provided on the passage of the laser beam such that the vertexes of the lenses face each other. An irradiation optical system 16 condenses the laser beam onto a workpiece 110 or diverges the laser beam therefrom. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cutting and scribing technique for brittle material substrates including glass substrates and semiconductor substrates.

  An FPD (flat panel display) is formed by cutting a single mother glass into a plurality of regions of a predetermined size. The size of FPD ranges from several tens of inches used for large LCD TVs to several inches such as mobile phone terminals, and the thickness of FPDs varies from several mm used for large LCD TVs to mobile phones. Wide range of about 0.5mm used for terminals.

  As a method of cutting a brittle material substrate such as glass, conventionally, a technique of forming a scribe line with a cutter such as diamond and breaking (cleaving) along the scribe line has been used. This method has a problem that glass powder and glass cullet are generated at the time of cleaving. In recent years, a technique (laser scribing) that uses a laser beam instead of a cutter for forming a scribe line has been developed.

  In laser scribing, while moving on a glass substrate along a planned processing line, a laser is irradiated to one point on the planned processing line to locally heat it, and then a cooling medium is injected near the heating region to cool it. As a result, thermal stress is generated in the direction of pulling the glass substrate perpendicular to the planned processing line according to the heat distribution on the laser substrate, and the scribe line along the planned processing line grows on the glass substrate. . Thereafter, mechanical stress is applied to the glass substrate by the breaker device, and the glass substrate is cleaved along the scribe line.

In addition, by adjusting heating conditions, cooling conditions, processing speed, etc., the scribe line is penetrated to the deep part in the thickness direction of the glass substrate, and the full cut that cleaves the glass substrate without breaking by the breaker device (Also called full body cut). A full cut using a laser is very useful from the viewpoint of mass productivity because it requires no post-processing by a breaker device and can cleave the glass substrate in a single process.
International Publication No. 03/008168 Pamphlet

  When the glass substrate is fully cut, the heating condition by the laser is extremely important as compared with the case where the scribe line is simply formed. The heating condition by the laser depends on the intensity distribution (beam cross-sectional profile) of the laser beam irradiation region (also referred to as an irradiation spot) in addition to the laser energy. That is, if the state of the laser beam is not optimized, full cutting cannot be performed, and even if full cutting is possible, the yield is low and the quality of the cross section of the glass is deteriorated.

  For example, Patent Document 1 discloses a technique for patterning a laser beam pattern so as to have a plurality of peaks in a direction along a planned scribe line (processed planned line). In the technique of Patent Document 1, a plurality of peaks are formed by superimposing a plurality of beams, and thus there is a problem that an optimum heating state for full cut cannot be realized.

  In particular, in order to fully cut various glass substrates of different materials and thicknesses with high quality and high yield, the applicant should pay attention not only to the direction of the planned processing line but also to the strength distribution in the vertical direction. Has come to be recognized as important.

  The present invention has been made in view of such problems, and an object thereof is to provide a processing technique for fully cutting a brittle material substrate such as a glass substrate with high quality or high yield.

  An embodiment of the present invention relates to a processing apparatus that cuts a brittle material substrate that is an object to be processed along a planned processing line. This processing apparatus includes a laser irradiation apparatus for patterning a laser beam into a long and narrow shape with a planned processing line in the longitudinal direction, and irradiating the patterned laser beam on the processing target line of the brittle material substrate, and in the vicinity of the laser irradiation region. A cooling device for injecting a cooling medium to cool a predetermined cooling region on the processing line, and a stage for moving the brittle material substrate relative to the laser irradiation region and the cooling region in the direction of the processing line. . The laser irradiation apparatus includes a pair of axicon lenses provided on the laser beam path and arranged such that their vertices face each other or face each other, and an irradiation optical system that focuses or diverges the laser beam. ,including.

  According to this aspect, by using a pair of axicon lenses, the laser beam can be patterned to have an intensity profile having a ring-like peak. By converging or diverging this beam, a laser beam having two peaks in the direction along the planned processing line is formed by patterning a single beam instead of superimposing a plurality of laser beams. Can do. Furthermore, the intensity distribution in the direction perpendicular to the planned processing line can be made into a shape suitable for full cut, which is different from the profile obtained by simply condensing the beam from the laser oscillator. In this specification, the “processing apparatus” includes not only an apparatus capable of full-cutting a brittle material substrate, but also a scribe apparatus for forming a scribe line on the brittle material substrate on the premise of a post-process by a breaker device. It is a concept.

The irradiation optical system includes a first cylindrical lens that is provided on the laser beam path and focuses the laser beam in a first direction perpendicular to the laser beam path direction, and the laser beam is in the path direction and the first direction. And a second cylindrical lens that diverges in a second direction perpendicular to.
By using a cylindrical lens, a laser irradiation region can be formed in an irradiation region of a desired size.

At least one of the pair of axicon lenses may be movable in the laser beam path direction.
In this case, since the distance between the apexes of the axicon lenses can be changed, the peak interval of the laser beam can be adjusted independently of the size of the laser irradiation region formed on the glass substrate.

The pair of axicon lenses may be movable in at least one direction parallel to the cross section of the laser beam.
In this case, the position of the peak of the laser beam can be adjusted independently of the size of the laser irradiation region formed on the glass substrate.

  The irradiation optical system may be provided closer to the brittle material substrate than the pair of axicon lenses.

  The first cylindrical lens and the second cylindrical lens may be independently movable in the laser beam path direction.

  The pair of axicon lenses and the irradiation optical system may be arranged on a straight line so that their optical axes are substantially perpendicular to the brittle material substrate.

  The pair of axicon lenses and the irradiation optical system may be mounted on a rotary head that can rotate around an axis perpendicular to the brittle material substrate. In this case, since the cutting direction can be changed by rotating the rotary head without rotating the brittle material substrate, productivity can be improved.

  You may further provide the optical axis adjustment part for adjusting the incident direction of the laser beam with respect to a pair of axicon lens and irradiation optical system.

  Another aspect of the present invention also relates to a processing apparatus for cutting a brittle material substrate, which is a processing target, along a planned processing line. This processing device patterns the laser beam into an annular shape, and condenses or diverges the laser beam, patterns it into a long and narrow shape whose processing target line is the longitudinal direction, and irradiates the patterned laser beam onto the processing target line of the brittle material substrate. A laser irradiation device that cools the brittle material substrate along the planned processing line, a cooling device that cools a predetermined cooling region on the processing planned line that is in the vicinity of the laser irradiation region, and jets a cooling medium. And a stage that is moved relative to the cooling region.

  By patterning the laser beam in an annular shape and condensing and irradiating it on the brittle material substrate, both the intensity distribution in the direction of the processing line of the laser beam and the intensity distribution in the vertical direction are fully cut. It can be set as the shape suitable for.

  Another aspect of the present invention also relates to a processing apparatus for cutting a brittle material substrate, which is a processing target, along a planned processing line. This processing apparatus includes a laser irradiation apparatus for patterning a laser beam into a long and narrow shape with a planned processing line in the longitudinal direction, and irradiating the patterned laser beam on the processing target line of the brittle material substrate, and in the vicinity of the laser irradiation region. A cooling device that cools a predetermined cooling area on the planned processing line by jetting a cooling medium, and a stage that moves the brittle material substrate relative to the laser irradiation area and the cooling area along the planned processing line. . The intensity distribution of the laser beam in the laser irradiation region has two peaks in the longitudinal direction and two peaks in the direction perpendicular to the longitudinal direction.

  According to this aspect, since there are two peaks in the direction perpendicular to the planned processing line, the brittle material substrate can be heated to a state suitable for full cut.

The laser beam may be generated by patterning a single laser beam.
When a plurality of laser beams are superimposed, the intensity distribution varies, and this problem can be solved by patterning a single laser beam.

  The laser irradiation apparatus may include a pair of axicon lenses provided on the laser beam path and arranged such that their vertices face each other or face each other, and an irradiation optical system that focuses the laser beam. Good.

  Yet another embodiment of the present invention relates to a method of cutting a brittle material substrate, which is an object to be processed, along a planned processing line. In this method, a laser beam is patterned into a long and narrow shape in which the processing line is in the longitudinal direction, and the patterned laser beam is irradiated onto the processing line of the brittle material substrate, and in the vicinity of the laser irradiation region and on the processing line. The step of cooling the predetermined cooling region by injecting the cooling medium is performed while moving the brittle material substrate in the direction of the planned processing line. The laser beam is patterned by a pair of axicon lenses provided on the path of the laser beam and arranged such that their vertices face each other or face each other and an irradiation optical system that collects the laser beam. .

  Still another aspect of the present invention also relates to a method of cutting a brittle material substrate that is an object to be processed along a planned processing line. In this method, the laser beam is patterned into an annular shape, condensed or diverged, and patterned into a long and narrow shape whose processing target line is in the longitudinal direction, and the patterned laser beam is irradiated onto the processing target line of the brittle material substrate. Performing a step of cooling a predetermined cooling region in the vicinity of the laser irradiation region on the planned processing line by injecting a cooling medium while moving the brittle material substrate relative to the laser irradiation region and the cooling region. To do.

  Still another embodiment of the present invention also relates to a method of cutting a brittle material substrate that is an object to be processed along a planned processing line. In this method, a laser beam is patterned into a long and narrow shape in which the processing line is in the longitudinal direction, and the patterned laser beam is irradiated onto the processing line of the brittle material substrate, and in the vicinity of the laser irradiation region and on the processing line. The step of cooling the predetermined cooling region by injecting the cooling medium is performed while moving the brittle material substrate in the direction of the planned processing line. The intensity distribution of the laser beam has two peaks in the longitudinal direction and two peaks in a direction perpendicular to the longitudinal direction.

  Still another embodiment of the present invention relates to an irradiation apparatus mounted on a processing apparatus that heats a brittle material substrate, which is an object to be processed, with a laser beam, and then injects a cooling medium to cool and cut. In this irradiation apparatus, a laser beam is patterned into a long and narrow shape whose processing line is in the longitudinal direction, and is irradiated onto the processing line of the brittle material substrate. The irradiation device is a pair of axes arranged on a straight line on the laser beam path such that the optical axis is substantially perpendicular to the brittle material substrate, with the vertices facing each other. A con lens and an irradiation optical system for condensing the laser beam are provided.

  Yet another embodiment of the present invention relates to a method for manufacturing a flat panel. This method includes the steps of manufacturing a mother glass on which a pixel circuit is formed, and cutting the mother glass by any of the above-described methods. According to this aspect, a plurality of flat panels can be cut out from the mother glass with high yield and high quality. The flat panel includes a liquid crystal display panel, a plasma display panel, an organic EL display panel, and the like.

  Yet another embodiment of the present invention relates to a flat panel. This flat panel is manufactured by a step of manufacturing a mother glass on which a pixel circuit is formed, and a step of cutting the mother glass by any one of the above-described methods.

  Yet another embodiment of the present invention relates to a display device. The display device includes the flat panel described above and a drive circuit that drives the flat panel.

  It should be noted that any combination of the above-described constituent elements, and those in which constituent elements and expressions of the present invention are mutually replaced between methods, apparatuses, systems, and the like are also effective as an aspect of the present invention.

  According to an aspect of the present invention, a brittle material substrate can be fully cut with high quality or high yield.

  The present invention will be described below based on preferred embodiments with reference to the drawings. The same or equivalent components, members, and processes shown in the drawings are denoted by the same reference numerals, and repeated descriptions are omitted as appropriate. The embodiments do not limit the invention but are exemplifications, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

  FIG. 1 is a block diagram illustrating an overall configuration of a processing apparatus 100 according to an embodiment. The processing apparatus 100 cuts (full cuts) the brittle material substrate, which is the processing object 110, from the start end 112 toward the end 114 along the planned processing line, or forms a scribe line on the surface thereof. Specific examples of the processing object 110 include various glass substrates used for FPD. The glass substrate may be a single plate or a laminated substrate.

  For simplification of explanation, the left direction in FIG. 1 is defined as the X direction, the front direction perpendicular to the paper surface is defined as the Y direction, and the upward direction is defined as the Z axis. In addition, the dimensions of each member and the like shown in some drawings are appropriately expanded or reduced for easy understanding within a scope not related to the essence of the invention, and the positional relationship between each member is easy to understand. For the sake of illustration, it is modified or changed as appropriate.

  The processing apparatus 100 includes a stage 2, a table 4, an initial crack generation unit 6, a laser light source 8, a laser irradiation device 10, a cooling device 20, a temperature sensor 30, and a control unit 32.

  The workpiece 110 is fixed on the table 4. As the fixing means, negative pressure adsorption may be used, or physical fixing means using an adhesive tape, a clamper or the like may be used. Alternatively, the position of the workpiece 110 may be fixed to the table 4 by its own weight. The workpiece 110 is disposed in parallel with the XY plane.

  The stage 2 moves the table 4 on which the workpiece 110 is fixed. By moving the table 4 in a scanning direction SCAN (in the direction opposite to the X axis) parallel to the planned processing line, the processing object 110 moves relative to a laser irradiation region and a cooling region described later. FIG. 1 assumes the case where the planned machining line is formed in the X-axis direction. Further, the stage 2 is configured to be able to adjust the angle Φ around the Z axis, and thereby the direction of the planned machining line with respect to the workpiece 110 can be adjusted.

The laser light source 8 is appropriately selected according to the wavelength dependency of the absorption rate of the workpiece 110. For example, in the case of a glass substrate used for FPD, a carbon dioxide gas laser (CO ₂ laser) having a wavelength of 10.6 μm is preferable. Available to: Since the glass substrate is transparent to visible light but opaque to infrared light, the energy of the laser light is efficiently absorbed and converted into heat. There are laser scribing devices and cutting devices that use lasers with wavelengths in the visible light, ultraviolet region, or near infrared region, but the glass to be processed is transparent to these wavelengths. . Therefore, the processing technique according to the present embodiment using a CO ₂ laser is completely different from the processing technique using a wavelength shorter than the near infrared in the heating or the subsequent cooling process. It should be noted that the obtained knowledge is not always useful for the processing technique according to the present embodiment.

  The laser light source 8 emits a laser beam LB1 having a circular beam profile. Usually, the cross-sectional intensity profile of a laser beam has a Gaussian distribution, but it may be a beam whose outer periphery is cut off by an aperture or the like, or may be a beam having another intensity distribution. In addition, the beam profile is usually a perfect circle, but the shape can be corrected by the irradiation optical system at the subsequent stage, so it may be an ellipse, a square, or a rectangle. Rather, it may be better to positively correct the shape of the laser beam emitted from the laser light source in order to achieve the optimum heating for full cut.

  The laser irradiation apparatus 10 patterns the laser beam LB1 emitted from the laser light source 8, and irradiates the patterned beam LB2 onto the planned processing line of the brittle material substrate that is the processing target 110. The laser beam LB2 irradiated to the workpiece 110 has a long and narrow shape with a planned processing line in the longitudinal direction.

  The size of the region (laser irradiation region) irradiated with the laser beam LB2 on the workpiece 110 is optimized according to the material and thickness of the workpiece 110. Furthermore, the size and shape may be changed in accordance with the position where the laser beam is irradiated.

  The cooling device 20 injects the cooling medium CM to a predetermined cooling region on the planned processing line in the vicinity of the region (laser irradiation region) irradiated with the laser on the workpiece 110. The cooling device 20 is configured by a nozzle that injects a mixture of gas and liquid, for example. The nozzle is configured to be movable with respect to the X-axis direction, and the distance between the cooling region and the tail side end of the laser irradiation region 40 depends on the material and thickness of the workpiece 110, the size of the laser irradiation region, and the like. Optimized.

  The initial crack generation unit 6 is provided to form an initial crack at the start end 112 of the workpiece 110 on the planned processing line. For example, the initial crack generation unit 6 is composed of a cutter such as diamond. The laser irradiation region and the cooling region are scanned along the planned processing line with the initial crack as a starting point, and a full cut split section grows using the initial crack as a seed. Depending on the object to be processed 110 and the processing conditions, a full cut may be possible without forming an initial crack.

  FIG. 2 is a plan view of the laser irradiation region 40 and the cooling region 44 formed on the processing target object 110 as viewed from above the processing target object 110. The laser irradiation area 40 and the cooling area 44 are arranged along a planned processing line 42 indicated by a one-dot chain line. In order to realize a high quality, high yield full cut, the heating and cooling conditions in the laser irradiation region 40 and the cooling region 44 are extremely important. For example, FPD glass panels are required to have high quality with a flat section of about ± 2 μm and a linearity of about ± 25 μm. The processing apparatus 100 according to the embodiment has several features for optimizing heating conditions and cooling conditions necessary for fully cutting a glass substrate with high quality.

  One feature of the processing apparatus 100 according to the embodiment is temperature control of the processing object 110. First, this temperature control will be described.

  The temperature sensor 30 in FIG. 1 monitors the temperature of a predetermined area 46 between the laser irradiation area 40 and the cooling area 44. The temperature sensor 30 is preferably a non-contact type, and for example, an infrared sensor can be used.

  The temperature sensor 30 outputs a signal (hereinafter referred to as a temperature signal) Stmp corresponding to the measured temperature to the control unit 32. The control unit 32 feedbacks the laser beam LB1 output from the laser light source 8 so that the value of the temperature signal Stmp matches a predetermined reference value by feedback, that is, the measured temperature of the predetermined region 46 matches the target value. Adjust the energy. The target temperature value is set to be equal to or lower than the softening point corresponding to the material of the workpiece 110.

  Conventional processing apparatuses generally use an output stabilization mechanism of the laser light source 8. That is, the energy of the laser beam LB1 is kept constant by the laser light source 8 regardless of the state of the workpiece 110. However, even if the energy of the laser beam LB1 is kept constant, if the coefficient of thermal diffusion changes according to the processing position of the processing object 110 or the cooling condition by the cooling device 20 is changed, the temperature of the laser irradiation region 40 will be increased. It will change.

  In order to reliably cut the workpiece 110 with high quality, it is important to cool the workpiece 110 after heating it to a predetermined peak temperature. As a result of experiments conducted under various conditions, the applicant of the present invention has not so wide a peak temperature range that can realize a high-quality, high-yield full cut, and even if the energy of the laser beam LB1 is kept constant, It has been recognized that the peak temperature deviates from a predetermined range, leading to a decrease in quality or a situation where full cutting cannot be performed.

  Based on this recognition, the processing apparatus 100 according to the embodiment is provided with a mechanism for controlling the laser light source 8 so that the temperature of the predetermined region 46 is constant, and the processing object 110 is reliably brought to a predetermined peak temperature. In addition to being able to be heated, temperature fluctuations can be suppressed, so that the quality can be improved.

  Furthermore, in order to realize a high-quality full cut, it is not sufficient to simply measure and feed back the temperature of the workpiece 110, and the position at which the temperature is measured is important. The predetermined region 46 is preferably set at a position on the planned processing line 42 and closer to the laser irradiation region 40 than the cooling region 44. More specifically, the predetermined region 46 is preferably located as close to the laser irradiation region 40 as possible, but when the laser irradiation region 40 overlaps, the reflected light of the laser beam is incident on the temperature sensor 30, so normal temperature measurement is performed. May interfere.

  Therefore, the predetermined region 46 is set to a position within 1 cm, preferably 2 to 3 mm from the tail end 41 of the laser irradiation region 40 so as not to overlap the laser irradiation region 40. If the predetermined region 46 is set at this position, the temperature at a place where the influence of cooling immediately after heating is small can be measured. The temperature thus measured is close to the peak temperature of the substrate. From another point of view, what is important in fully cutting the workpiece 110 is to reliably heat the workpiece 110 to a predetermined peak temperature, and to further suppress variations in the peak temperature. It can be said. Therefore, measuring the temperature immediately adjacent to the laser irradiation region 40 is significant because a temperature having a strong correlation with the peak temperature can be measured as compared with the case where the temperature near the cooling region 44 is measured.

  The optimum peak temperature of the workpiece 110 varies depending on the distance from both end portions 112 and 114. Therefore, the processing apparatus 100 according to the embodiment has a function of changing a target temperature value in accordance with the heating position.

  FIG. 3 is a plan view of the workpiece 110 to be segmented as viewed from above. A portion between the start end 112 and the end end 114 of the workpiece 110 is virtually divided into a plurality of segments SEG1 to SEG5. The number of segments and the length of the segments are arbitrary and are design matters.

  The control unit 32 is configured such that a temperature target value can be set independently for each segment. As a result, the workpiece 110 can be heated to an optimum temperature according to the distance from both end portions 112 and 114.

  The temperature control by feedback of the control unit 32 can be switched between valid and invalid independently for each segment. The adjustment of the energy of the laser beam by feedback may be stopped in at least one of the predetermined range from the start end 112 and the predetermined range from the end end 114, that is, at least one of the first segment SEG1 and the fifth segment SEG5. From this viewpoint, it is desirable to divide the segment into three or more segments including a segment including the start end, a segment including the end end, and a segment including none.

  The segment SEG1 including the start end 112 and the segment SEG5 including the end end 114 are different from the intermediate segments SEG2 to SEG4 in terms of the thermal diffusion boundary condition. Therefore, if feedback is performed so as to keep the monitored temperature constant, the actual breaking line may deviate from the planned machining line 42 or the cross-sectional accuracy may be deteriorated. However, if the feedback is invalidated, these problems can be solved. .

  Returning to FIG. In addition to adjusting the energy of the laser beam LB1 of the laser light source 8, the control unit 32 controls the scanning speed (also referred to as processing speed) of the stage 2. The control unit 32 switches between three modes: a constant speed mode for moving the workpiece 110 at a constant speed, an acceleration mode for increasing the moving speed of the workpiece 110 with time, and a deceleration mode for decreasing the moving speed with time. An arbitrary mode can be assigned to each segment SEG described above. For example, the first segment SEG1 including the start end 112 is processed in the acceleration mode, the fifth segment SEG5 including the end end 114 is processed in the deceleration mode, and the intermediate segments SEG2 to SEG4 are processed in the constant speed mode.

  In the acceleration mode and the deceleration mode, it is possible to switch between a first mode in which shifting is performed at a constant acceleration from the initial speed to the final speed and a second mode in which the speed is changed according to a trigonometric function (sine curve).

  Further, the control unit 32 can set the scan speed (initial speed, final speed) for each segment. The scanning speed can be set in the range of 0 to 500 mm / s, and is typically selected between 5 and 150 mm / s. By optimizing the two parameters of the target temperature and the processing speed of the processing object 110 according to the processing position, a high-quality full cut can be realized. As described above, if the processing speed is changed while the laser energy is kept constant, the temperature of the processing object 110 changes. On the other hand, by keeping the temperature of the predetermined region 46 in the vicinity of the laser irradiation region 40 constant by feedback, the temperature of the workpiece 110 is kept at the target value even if the processing speed is changed. That is, it can be said that one of the advantages of the processing apparatus 100 according to the embodiment is that the processing speed and the heating temperature can be set independently.

  The above is the characteristic configuration and control of the processing apparatus 100 as a whole.

  Subsequently, a heating technique and a cooling technique for realizing a higher quality full cut by combining with the above-described control mechanism will be described in order. However, the following heating and cooling techniques may be used independently regardless of the control method described above.

  First, the heating technique will be described. FIG. 4 is a diagram showing a laser irradiation region formed on the workpiece 110. FIG. 4 shows the shape of the laser irradiation region 40 when viewed from the upper surface of the workpiece 110 and the intensity distributions in the X and Y directions of the laser beam LB2.

  The intensity distribution of the laser beam in the laser irradiation region in the beam longitudinal direction (X-axis direction) has two peaks. That is, on the object to be processed 110, two spots with high injected heat density are formed in the direction of the planned processing line 42. Also, the intensity distribution in the direction perpendicular to the long direction (short direction) is not a Gaussian distribution but has a flat shape. The beam pattern in FIG. 4 is not formed by superimposing a plurality of beams having different peak positions, but is also formed by patterning the laser beam LB emitted from the single laser light source 8. This is one of the features of the form.

Hereinafter, a technique for patterning the laser beam shown in FIG. 4 will be described.
FIG. 5 is a block diagram illustrating a configuration of the laser irradiation apparatus 10 according to the embodiment. A laser beam LB1 emitted from a laser light source 8 indicated by a solid line in FIG. FIG. 6 is a diagram schematically showing the shape of the laser beam LB in each part of the laser irradiation apparatus 10 of FIG.

  FIG. 5 shows a laser light source 8 and the like in addition to the laser irradiation apparatus 10. The laser light source 8 can be positioned and adjusted in the Z-axis direction.

  The laser irradiation apparatus 10 includes a pair of axicon lenses (axicon lens pair 11) including a first axicon lens (conical lens) 12 and a second axicon lens 14, an irradiation optical system 16, and first mirrors M1 to M3. A mirror M3 is provided.

  The axicon lens pair 11 and the irradiation optical system 16 are provided on the path of the laser beam LB1. The first axicon lens 12 and the second axicon lens 14 are arranged so that their vertices face each other. At least one of the first axicon lens 12 and the second axicon lens 14 is mounted on a movable mounter, and is configured to be movable in the laser beam path direction (Z-axis direction). That is, the distance Δz between the apexes of the first axicon lens 12 and the second axicon lens 14 can be adjusted.

As shown in FIG. 6, the laser beam LB3 that has passed through the axicon lens pair 11 has an annular (doughnut-shaped) intensity distribution. The diameter of the ring can be adjusted in accordance with the distance Δz between the apexes of the axicon lens pair 11, and as a result, the peak interval of the intensity distribution in the direction of the processing line of the laser beam LB2 that is finally generated is It can be adjusted independently of the size of the laser irradiation area.
The axicon lens pair 11 can be arranged such that the positions of the first axicon lens 12 and the second axicon lens 14 in the vertical direction (Z direction) are interchanged so that the vertices do not face each other, that is, the opposite sides face each other. It is.

The axicon lens pair 11 is preferably movable in at least one direction parallel to the cross section of the laser beam, that is, in either the X-axis direction or the Y-axis direction, or both. By moving the axicon lens pair 11 as a unit in the X-axis direction or the Y-axis direction, the center of the ring of the laser beam LB3 in FIG. 6 can be offset. This means that the position of the peak intensity (see FIG. 4) of the laser irradiation region 40 to be finally generated can be arbitrarily adjusted, which is convenient when optimizing the heating state of the workpiece 110. It is.
Furthermore, it is desirable to configure the first axicon lens 12 and the second axicon lens 14 so that each can move independently. With this configuration, the two intensity peaks generated in the X-direction and Y-direction intensity profiles in FIG. 4 can be changed from the same height to different heights, and a spatially asymmetric profile can be realized.

  The irradiation optical system 16 condenses or diverges the laser beam LB3 that has passed through the axicon lens pair 11 and projects the laser beam LB3 onto the laser irradiation region on the workpiece 110. The enlargement / reduction rate of the light collection and divergence may be determined according to the diameter of the original laser beam LB1 and the size of the laser irradiation region 40.

  The irradiation optical system 16 includes a first cylindrical lens CL1 and a second cylindrical lens CL2. The first cylindrical lens CL1 and the second cylindrical lens CL2 are arranged such that the cross sections having curvatures are perpendicular to each other.

  The first cylindrical lens CL1 is an optical element that condenses the laser beam in a first direction (Y-axis direction) perpendicular to the path direction (Z-axis opposite direction). Specifically, the first cylindrical lens CL1 is a plano-convex cylindrical lens, and reduces the laser beam LB2 irradiated to the workpiece 110 in the Y-axis direction. The curvature of the first cylindrical lens CL1 is determined according to the diameter of the original laser beam LB1 and the size of the laser irradiation region. As an alternative to the first cylindrical lens CL1, a concave cylindrical mirror may be used.

  As shown in FIG. 6, the laser beam LB4 that has passed through the first cylindrical lens CL1 has a shape obtained by reducing the laser beam LB3 in the Y-axis direction. As the laser beam LB4 approaches the workpiece 110, the width in the Y-axis direction decreases, and the final intensity distribution in the Y-axis direction matches that in FIG.

  The second cylindrical lens CL2 is an optical element that diverges the laser beam in a second direction (X-axis direction) perpendicular to the path direction (Z-axis opposite direction) and the first direction (Y-axis direction). Specifically, the second cylindrical lens CL2 is a plano-concave cylindrical lens, and expands the laser beam LB2 irradiated to the workpiece 110 in the X-axis direction. Similar to the first cylindrical lens CL1, the curvature of the second cylindrical lens CL2 is also determined according to the diameter of the original laser beam LB1 and the size of the laser irradiation region. As an alternative to the second cylindrical lens CL2, a convex cylindrical mirror may be used.

  As shown in FIG. 6, the laser beam LB5 that has passed through the second cylindrical lens CL2 has a shape obtained by enlarging the laser beam LB4 in the X-axis direction. As the laser beam LB5 approaches the workpiece 110, the width in the X-axis direction widens, and the final intensity distribution in the X-axis direction matches that in FIG.

  The first cylindrical lens CL1 and the second cylindrical lens CL2 are arranged so that the processing object 110 side is a plane, but may be in opposite directions, and the positions of the first cylindrical lens CL1 and the second cylindrical lens CL2 are It may be replaced.

The first cylindrical lens CL1 and the second cylindrical lens CL2 are mounted on a movable mounter, and can be moved independently in the laser beam path direction. That is, the distance between the first cylindrical lens CL1 and the workpiece 110 and the distance between the second cylindrical lens CL2 and the workpiece 110 can be adjusted independently. As a result, the length L in the X-axis direction and the width W in the Y-axis direction of the laser irradiation region 40 shown in FIG. 4 can be adjusted independently. The length L and the width W of the laser irradiation region 40 are defined by the full width at half maximum (Full Width at Half Maximum).
Further, by adjusting the positions of the first cylindrical lens CL1 and the second cylindrical lens CL2 in the Z-axis direction, the position of the peak intensity in FIG. 4 can be changed.

  The order of arrangement of the axicon lens pair 11 and the irradiation optical system 16 can be switched, but preferably, as shown in the figure, the axicon lens pair 11 is provided on the laser light source 8 side, and the irradiation optical system 16 is provided. In addition, it is preferable that the processing target object 110 side be disposed with respect to the axicon lens pair 11. By making the beam before being extended in the X-axis direction by the second cylindrical lens CL2 enter the axicon lens pair 11, the area of the axicon lens pair 11 can be reduced. In addition, by allowing the beam before being condensed in the Y-axis direction by the first cylindrical lens CL1 to enter the axicon lens pair 11, the alignment becomes simple. If the focused beam is incident on the axicon lens pair 11, a slight deviation of the optical axis will appear as a deviation of the position of the intensity peak of the finally formed laser beam LB2.

  If the axicon lens pair 11 and the irradiation optical system 16 are arranged on the laser beam path, their optical axes do not necessarily coincide with each other. For example, the optical axis of the irradiation optical system 16 may coincide with the Z axis, the axicon lens pair 11 may be disposed at a position before being folded back by the third mirror M3, and the optical axes thereof may coincide with the X axis. However, from the viewpoint of productivity, as shown in FIG. 5, the axicon lens pair 11 and the irradiation optical system 16 are arranged on a straight line so that their optical axes are substantially perpendicular to the workpiece 110. It is desirable. In this case, the axicon lens pair 11 and the irradiation optical system 16 can be attached to a rotary head 18 that can rotate around a rotary shaft 19 indicated by a one-dot chain line perpendicular to the workpiece 110.

  After the workpiece 110 is cut in the X-axis direction, the rotary head 18 is rotated 180 degrees with respect to the X-axis, and the scan direction of the workpiece 110 is reversed to turn back and cut the workpiece 110. Can do. In addition, the planned machining line can be set in the Y-axis direction by rotating the rotary head 18 by 90 degrees or 270 degrees with respect to the X-axis and moving the stage 2 in the Y-axis direction. That is, machining in the X-axis direction and the Y-axis direction can be performed without rotating the workpiece 110.

  The shutter 9 is provided to block the processing object 110 from being inadvertently irradiated with the laser beam LB1 emitted from the laser light source 8. When the fourth mirror M4 functions as a substantial shutter and the fourth mirror M4 is arranged on the path of the laser beam LB1, the laser beam LB1 is reflected and incident on the beam damper BD, and the laser for the laser irradiation device 10 is reflected. The supply of the beam LB1 is stopped. When the fourth mirror M4 is removed from the path of the laser beam LB1, the laser beam LB1 is supplied to the laser irradiation device 10.

  The laser diode 7 and the fifth mirror M5 are provided for alignment of optical elements in the laser irradiation apparatus 10. Since the laser beam LB1 is in the infrared region and is not visible to the human eye, a visible laser beam (illustrated by a broken line) is used as an alternative. The fifth mirror M5 matches the optical axis of the beam from the laser diode 7 with the optical axis of the laser beam LB1 from the laser light source 8.

  The first mirror M1 and the second mirror M2 and the third mirror M3 constituting the optical axis adjusting unit 17 are provided to guide the laser beam LB1 to the axicon lens pair 11. The first mirror M1 and the second mirror M2 are mounted on a movable mounter for adjusting the inclination with respect to the optical axis, and the incident angle of the laser beam with respect to the axicon lens pair 11 and the irradiation optical system 16 is adjusted. The user of the laser irradiation apparatus 10 adjusts the optical axis adjustment unit 17 by relying on the visible laser beam emitted from the laser diode 7, and transmits the laser beam LB1 from the invisible laser light source 8 to the axicon lens pair. 11 and the irradiation optical system 16 can be appropriately incident.

The above is the detailed configuration of the laser irradiation apparatus 10.
According to this processing apparatus 100, the laser beam can be patterned in a state suitable for full cut, and the optical system can also be configured simply.
The shape and intensity distribution of the laser irradiation region 40 suitable for full cut are:
(1) It has an elongated shape extended in the planned processing line direction and has two intensity peaks in the planned processing line direction.
(2) having two intensity peaks in the direction perpendicular to the planned processing line;
Satisfying at least one, preferably both. By using a laser beam having this characteristic, a full cut with high quality and high yield can be realized.

  From another point of view, by using the laser irradiation apparatus 10 shown in FIG. 5, the laser irradiation region 40 that satisfies both the above (1) and (2) can be suitably formed. Although it is difficult or substantially impossible to form the laser irradiation region 40 having this intensity distribution by superimposing a plurality of beams, a single laser can be obtained by using the laser irradiation apparatus 10 of FIG. It can be easily generated by beam patterning.

  Furthermore, the length L, width W, peak distances ΔLpk, ΔWpk, and peak intensities ILpk, IWpk of the laser irradiation region 40 in FIG. 4 are extremely important parameters for full-cutting the workpiece 110. However, according to the laser irradiation apparatus 10 of FIG. 5, each parameter can be adjusted individually.

  From another point of view, in order to realize a high-quality full cut, instead of or in addition to forming the laser irradiation region 40 satisfying the above (1) and (2), FIG. It can be said that it is important to use the laser irradiation apparatus 10 provided with the axicon lens pair 11 shown. When the laser beam is patterned using the laser irradiation device 10 of FIG. 5, depending on the position of each optical element, the laser irradiation region 40 formed on the workpiece 110 does not necessarily have both (1) and (2). May not meet. However, depending on the material and thickness of the workpiece 110, a high-quality full cut can be realized by using the laser irradiation region 40 formed using the laser irradiation apparatus 10 having the above-described characteristics.

  From another viewpoint, it can be said that forming the laser irradiation region 40 by the laser irradiation device 10 patterning the laser beam in an annular shape and condensing or diverging it contributes to a high quality full cut.

  The processing apparatus 100 according to the embodiment is also characterized by a cooling process by the cooling apparatus 20. The details of the cooling process will be described below. In addition, the cooling process described below realizes a high quality, high yield full cut in combination with the above-described characteristic laser irradiation apparatus 10, but the laser irradiation apparatus 10 has a different configuration. Even so, the same actions and effects can be achieved.

  Returning to FIG. The width Wc of the cooling region 44 in the direction perpendicular to the processing line 42 (that is, the Y-axis direction) is shorter than the width W of the laser irradiation region 40 in the Y-axis direction.

  Conventionally, in order to rapidly cool the workpiece 110, it is common to spray a cooling medium on a region wider than the width W of the laser irradiation region 40 using a two-fluid nozzle. However, in this case, it is necessary to relatively increase the amount of heat applied to the workpiece 110 by the laser beam, and it cannot be said that heating / cooling suitable for full cut has been realized. On the other hand, in the processing apparatus 100 according to the embodiment, by reducing the width Wc of the cooling region 44, heating / cooling suitable for full cut can be realized, the quality of the cut surface can be improved, or the yield can be improved. Can be increased.

  The cooling medium CM is preferably a droplet ejected from a nozzle. The diameter (particle diameter) of the droplet is desirably 80 μm or less, and more preferably 30 μm or less. For example, water droplets at room temperature can be used as the cooling medium. By using water, the workpiece 110 can be cooled at low cost.

  As in the prior art, when the cooling medium CM is sprayed by the two liquid nozzles, the particle size of the droplets is about 100 μm at the minimum. On the other hand, by making the diameter of the droplets 30 μm or less, cooling more suitable for full cut can be realized.

  The above cooling process can be realized by using a nozzle described below. FIG. 7 is a diagram illustrating a configuration of the nozzle 21 suitable for the cooling device 20. The nozzle 21 has a coaxial double tube structure. The inner wall of the inner tube 22 forms a central passage 26. The outer tube 24 is provided coaxially with the inner tube 22, and an outer passage 28 is formed between the outer wall of the inner tube 22 and the inner wall of the outer tube 24.

  Although such a nozzle is usually marketed as being used for the tip of a dispenser or spray gun, the present inventor has focused on its configuration and has come to consider using it to realize the above-described cooling process. .

  A liquid such as water is supplied to the central passage 26 from the outside. The outer passage 28 is supplied with a gas, for example air, maintained at a constant pressure via a regulator. A pressure is adjusted according to cooling conditions centering on about 5-6 MPa.

  The nozzle 21 in FIG. 7 ejects liquid from the central passage 26 of the double tube and gas from the outer passage 28. The liquid ejected from the central passage 26 is finely crushed by the pressure of the gas ejected from the outer passage 28 and ejected as droplets. According to the nozzle 21 in FIG. 7, a droplet having a diameter smaller than 80 μm can be sprayed on the workpiece 110 by appropriately setting the gas pressure.

  Furthermore, since the gas ejected from the outer passage 28 acts as a guide for confining the droplets, the region where the droplets are ejected can be limited to a desired cooling region.

  Note that the tip of the nozzle 21 is desirably arranged with a gap of 2 to 3 mm from the surface of the workpiece 110. In order to realize a better cooling state, the nozzle 21 may be inclined from the direction perpendicular to the surface of the workpiece 110 (Z-axis direction) to the X-axis direction.

  The width Wc of the cooling region 44 shown in FIG. 2 is determined according to the diameter φi of the central passage 26 of the nozzle 21 and the diameter φo of the outer passage 28. The width W of the laser irradiation region 40 is optimized within a certain range on the basis of, for example, the same degree as the thickness of the workpiece 110. Since the width Wc of the cooling region 44 is preferably narrower than that, it is desirable to use the nozzle 21 having a diameter as small as possible in order to fully cut a substrate having various thicknesses with the same nozzle.

  If a nozzle with a diameter φi of the central passage 26 of 2.84 mm is used, a full cut can be made, but there may be cases where the processing accuracy and quality are not satisfactory. If improved and a 0.58 mm nozzle is used, a very high quality full cut can be achieved. When a glass substrate of about 0.1 mm to 5 mm is fully cut, the diameter φi of the central passage is in the range of 0.4 mm to 0.9 mm, and it is preferable to select a thin one as much as possible.

  As described above, the processing apparatus 100 according to the embodiment is characterized by the temperature control, the heating process, and the cooling process. By combining these, high-precision and high-quality laser processing can be realized. However, even if another alternative technique is used as one of the processes and features, the characteristic technique according to the present invention is exhibited, and this aspect is also effective as the present invention.

  Although the present invention has been described using specific words and phrases based on the embodiments, the embodiments are merely illustrative of the principles and applications of the present invention, and the embodiments are defined in the claims. Many modifications and arrangements can be made without departing from the spirit of the present invention.

It is a block diagram which shows the whole structure of the processing apparatus which concerns on embodiment. It is the top view which looked at the laser irradiation area | region and cooling area | region formed on a workpiece from the upper side of a workpiece. It is the top view which looked at the processed object segmented from the upper direction. It is a figure which shows the mode of the laser irradiation area | region formed on a workpiece. It is a block diagram which shows the structure of the laser irradiation apparatus which concerns on embodiment. It is a figure which shows typically the shape of the laser beam in each part of the laser irradiation apparatus of FIG. It is a figure which shows the structure of the nozzle suitable for a cooling device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Processing apparatus, 2 ... Stage, 4 ... Table, 6 ... Initial crack production | generation part, 7 ... Laser diode, 8 ... Laser light source, 9 ... Shutter, 10 ... Laser irradiation apparatus, 12 ... 1st axicon lens, 14 ... Second axicon lens, 16 ... irradiation optical system, 17 ... optical axis adjusting unit, 18 ... rotating head, 19 ... rotating shaft, 20 ... cooling device, 21 ... nozzle, 22 ... inner tube, 24 ... outer tube, 26 ... Central passage, 28 ... outer passage, 30 ... temperature sensor, 32 ... control unit, 40 ... laser irradiation region, 42 ... processing line, 44 ... cooling region, 46 ... predetermined region, CL1 ... first cylindrical lens, CL2 ... first 2 cylindrical lenses, M1 ... first mirror, M2 ... second mirror, M3 ... third mirror, 110 ... workpiece, 112 ... start end, 114 ... end, LB ... laser Over-time, CM ... cooling medium.

Claims (16)

A processing apparatus for cutting a brittle material substrate, which is a processing object, along a planned processing line,
A laser irradiation apparatus for patterning a laser beam into a long and narrow shape in which the processing line is in the longitudinal direction, and irradiating the patterned laser beam on the processing line of the brittle material substrate;
A cooling device that cools a predetermined cooling region on the planned processing line by injecting a cooling medium;
A stage that moves the brittle material substrate relative to the laser irradiation region and the cooling region in the direction of the planned processing line;
With
The laser irradiation device is provided on a path of the laser beam,
A pair of axicon lenses arranged such that their vertices face each other or face each other; and
An irradiation optical system for condensing or diverging the laser beam;
The processing apparatus characterized by including. The irradiation optical system is provided on a path of the laser beam,
A first cylindrical lens for condensing the laser beam in a first direction perpendicular to a path direction of the laser beam;
A second cylindrical lens that diverges the laser beam in a second direction perpendicular to the path direction and the first direction;
The processing apparatus according to claim 1, comprising:   The processing apparatus according to claim 1, wherein at least one of the pair of axicon lenses is movable in a path direction of the laser beam.   The processing apparatus according to claim 1, wherein the pair of axicon lenses are movable in at least one direction parallel to a cross section of the laser beam.   The processing apparatus according to claim 1, wherein the irradiation optical system is provided closer to the brittle material substrate than the pair of axicon lenses.   The processing apparatus according to claim 2, wherein the first cylindrical lens and the second cylindrical lens are independently movable in a path direction of the laser beam.   2. The processing apparatus according to claim 1, wherein the pair of axicon lenses and the irradiation optical system are arranged on a straight line such that their optical axes are substantially perpendicular to the brittle material substrate. .   8. The processing apparatus according to claim 7, wherein the pair of axicon lenses and the irradiation optical system are mounted on a rotary head that is rotatable about an axis perpendicular to the brittle material substrate.   The processing apparatus according to claim 7, further comprising an optical axis adjustment unit for adjusting an incident direction of the laser beam with respect to the pair of axicon lenses and the irradiation optical system. A processing apparatus for cutting a brittle material substrate, which is a processing object, along a planned processing line,
A laser beam that is patterned into an annular shape and condensed or diverged to pattern the laser beam into an elongated shape whose longitudinal direction is the longitudinal direction, and the patterned laser beam is irradiated onto the planned processing line of the brittle material substrate An irradiation device;
A cooling device that cools a predetermined cooling region on the planned processing line by injecting a cooling medium;
A stage for moving the brittle material substrate relative to the laser irradiation region and the cooling region along the planned processing line;
A processing apparatus comprising: A processing apparatus for cutting a brittle material substrate, which is a processing object, along a planned processing line,
A laser irradiation apparatus for patterning a laser beam into a long and narrow shape in which the planned processing line is in the longitudinal direction, and irradiating the patterned laser beam on the planned processing line of the brittle material substrate;
A cooling device that cools a predetermined cooling region on the planned processing line by injecting a cooling medium;
A stage for moving the brittle material substrate relative to the laser irradiation region and the cooling region along the planned processing line;
With
The intensity distribution of the laser beam in the laser irradiation region has two peaks in the longitudinal direction and two peaks in a direction perpendicular to the longitudinal direction.   The processing apparatus according to claim 11, wherein the laser beam is generated by patterning a single laser beam. The laser irradiation device is provided on a path of the laser beam,
A pair of axicon lenses arranged such that their vertices face each other or face each other; and
An irradiation optical system for condensing or diverging the laser beam;
The processing apparatus according to claim 12, comprising: A method of cutting a brittle material substrate that is an object to be processed along a planned processing line,
Patterning a laser beam into a long and narrow shape in which the processing line is in the longitudinal direction, and irradiating the patterned laser beam on the processing line of the brittle material substrate;
Cooling a predetermined cooling region on the planned processing line by injecting a cooling medium;
Is performed while moving the brittle material substrate relative to the laser irradiation region and the cooling region,
The laser beam is
Provided on the path of the laser beam;
A pair of axicon lenses arranged such that their vertices face each other or face each other; and
An irradiation optical system for condensing or diverging the laser beam;
A method characterized by being patterned by: A method of cutting a brittle material substrate that is an object to be processed along a planned processing line,
The laser beam is patterned into an annular shape, condensed or diverged, and patterned into a long and narrow shape in which the processing line is in the longitudinal direction, and the patterned laser beam is irradiated onto the processing line of the brittle material substrate. Steps,
Cooling a predetermined cooling region on the planned processing line by injecting a cooling medium;
Is performed while the brittle material substrate is moved relative to the laser irradiation region and the cooling region. A method of cutting a brittle material substrate that is an object to be processed along a planned processing line,
Patterning a laser beam into a long and narrow shape in which the processing line is in the longitudinal direction, and irradiating the patterned laser beam on the processing line of the brittle material substrate;
Cooling a predetermined cooling region on the planned processing line by injecting a cooling medium;
Is performed while moving the brittle material substrate relative to the laser irradiation region and the cooling region,
The intensity distribution of the laser beam has two peaks in the longitudinal direction and two peaks in a direction perpendicular to the longitudinal direction.

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