CN103282317B - The cut-off method of brittle substrate - Google Patents

Abstract

Irradiation by laser beam LB forms the 1st score line 52a be made up of vertical slight crack 53a, the 2nd score line 52b be made up of vertical slight crack 53b with blowing of the cooling media from cooling jet 37.Afterwards to the 2nd score line 52b once again irradiating laser light beam LB vertical slight crack 53b is stretched, with the 2nd score line 52b, brittle substrate 50 is cut off.Secondly, the intersection area of cutting off line 54 and the 1st score line 52a is covered with sheet glass 61 or water droplet 62.Afterwards, except intersection area to the 1st score line 52a once again irradiating laser light beam LB vertical slight crack 53a is stretched, with the 1st score line 52a, brittle substrate 50 is cut off.Whereby, the generation of breaking of intersection point part is suppressed in the occasion using laser to be cut off by brittle substrate in two directions crossed one another.

Description

Cutting method of brittle material substrate

technical field

The present invention relates to a method of irradiating a laser beam on a brittle material substrate and cutting the brittle material substrate along two directions intersecting each other.

Background technique

Conventionally, as a cutting method for brittle material substrates such as glass substrates and ceramic substrates, a method of cutting the substrate by applying an external force from a vertical direction along the scribed lines after forming scribed lines by pressing and rotating a knife wheel etc. has been widely used.

Generally, when a cutter wheel is used for scribing a brittle material substrate, the mechanical stress applied to the brittle material substrate by the cutter wheel tends to generate defects on the substrate, and cracks due to the above defects occur when breaking.

In response to the above-mentioned problems, a method of cutting a brittle material substrate using a laser has been put into practical use in recent years. This method is to irradiate the substrate with a laser beam and heat the substrate to less than the melting temperature, and then cool the substrate with a cooling medium to cause thermal stress on the substrate, so that the thermal stress causes cracks in a substantially vertical direction from the surface of the substrate. former. The cutting method of the brittle material substrate using the laser beam utilizes thermal stress, so the tool does not directly contact the substrate, the cut surface becomes a smooth surface with few cracks, and the strength of the substrate is maintained.

In addition, for example, Patent Document 1 proposes a method of cutting a brittle material substrate in two directions intersecting each other using laser light. This proposed method is to irradiate a laser beam on a brittle material substrate to form a first crack in a half-cut state, and then similarly irradiate a laser beam to form a second crack in a half-cut state that intersects with the first crack. 2. The cracks are completely cut by irradiating the laser beam again.

prior art literature

patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2001-130921

Contents of the invention

[Problem to be solved by the invention]

However, in the method proposed above, when the brittle material substrate is fully cut by irradiating the laser beam again to the first crack and the second crack, cracks may occur at the intersection of the first crack and the second crack. If cracks occur at the intersections of the cut brittle material substrates at the corners, the dimensional accuracy of the cut brittle material substrates will decrease, and the generated glass shavings will adhere to the substrate surface, causing problems.

The present invention is made in view of such conventional problems, and an object of the present invention is to provide a method for suppressing the occurrence of cracks at intersections when a brittle material substrate is cut in two directions intersecting each other using laser light.

[means to solve the problem]

According to the present invention, there is provided a method for cutting a brittle material substrate, comprising: forming a first scribe line and a second scribe line formed by vertical cracks intersecting each other on a brittle material substrate; The step of moving the laser beam relative to the line and the second scribe line while irradiating it to extend the vertical crack and cut the substrate with the first scribe line and the second scribe line, is characterized in that:

When the laser beam is irradiated along the first ruled line and/or the second ruled line, the laser beam irradiation amount to the intersection area of the first ruled line and the second ruled line is lower than that of the laser beam other than the intersection area. Reduced exposure.

Here, it is preferable that the laser beam irradiation amount to the intersection area of the first ruled line and the second ruled line is 50% or less of the laser beam irradiation amount other than the intersection area.

In addition, by controlling the output of the laser beam, the irradiation amount of the laser beam to the intersection area of the first scribed line and the second scribed line may be reduced. In addition, the intersection region of the first scribed line and the second scribed line may be covered with a covering member that absorbs or reflects the laser beam to reduce the irradiation amount of the laser beam to the intersection region. In addition, the intersection area of the first scribe line and the second scribe line may be covered with a liquid that absorbs or reflects the laser beam to reduce the irradiation amount of the laser beam to the intersection area.

In addition, the intersection region is preferably a region having a width of 5 mm or less on the upstream and downstream sides of the relative movement direction of the laser beam from the intersection of the first ruled line and the second ruled line.

In addition, the first scribed line and the second scribed line are irradiated while moving the laser beam relatively to the aforementioned substrate, and after heating the aforementioned substrate until the melting temperature is lower than the melting temperature, thereafter blowing a cooling medium to the aforementioned substrate for cooling, so that by The formation of thermal stress generated by the aforementioned substrate is ideal.

[Effect of the invention]

According to the method for cutting a brittle material substrate of the present invention, when the brittle material substrate is cut in two directions intersecting each other, it is possible to suppress the occurrence of cracks at intersections. Accordingly, the dimensional accuracy of the brittle material substrate after cutting is improved, and problems caused by glass shavings are significantly suppressed.

Description of drawings

Fig. 1 is a schematic diagram showing an example of a cutting device capable of carrying out the cutting method of the present invention.

FIG. 2 is a diagram illustrating an operational state of laser scribing.

Fig. 3 is a step diagram showing an example of the cutting method of the present invention.

FIG. 4 is a diagram showing an example of adjusting the irradiation amount to the intersection area of the laser beam LB and the laser irradiation amount in the intersection area.

FIG. 5 is a diagram showing an example of adjustment of the irradiation amount to the intersection area of the laser beam LB and the laser irradiation amount in the intersection area.

FIG. 6 is a diagram showing an example of the case where the adjustment of the irradiation amount to the intersection area of the laser beam LB is performed with a covering member.

FIG. 7 is a diagram showing an example in which the adjustment of the irradiation amount to the intersection area of the laser beam LB is performed with a liquid.

[Description of main component symbols]

Detailed ways

Although the cutting method of the brittle material substrate of the present invention will be described in detail below, the present invention is not limited to these implementation forms.

Fig. 1 is a schematic diagram showing an example of a cutting device capable of carrying out the cutting method of the present invention. In the cutting device of FIG. 1 , a slide platform 12 movable in a direction perpendicular to the paper (direction Y) is provided on a stand 11, a pedestal 19 movable in a left-right direction (direction X) of the drawing on the slide platform 12, The rotating mechanism 25 provided on the pedestal 19, and the brittle material substrate 50 placed and fixed on the rotating platform 26 provided on the rotating mechanism 25 can freely move in the horizontal plane by these moving means.

The sliding platform 12 is movably mounted on a pair of guide rails 14 and 15 arranged in parallel at a predetermined distance on the upper surface of the platform 11 . In addition, between the pair of guide rails 14 and 15, a ball screw 13 is provided parallel to the pair of guide rails 14 and 15 and can be rotated forward and backward by a motor not shown. In addition, a ball nut 16 is provided on the bottom surface of the slide table 12 . The ball nut 16 is screwed to the ball screw 13 . The ball nut 16 moves in the Y direction by the forward or reverse rotation of the ball screw 13 , so that the sliding platform 12 on which the ball nut 16 is mounted moves in the Y direction on the pair of guide rails 14 , 15 .

In addition, the pedestal 19 is movably supported by a pair of guide members 21 arranged in parallel with a predetermined distance apart on the slide table 12 . In addition, between the pair of guide members 21 and parallel to the pair of guide members 21, a ball screw 22 that can be rotated forward and backward by a motor 23 is provided. In addition, a ball nut 24 is provided on the bottom surface of the pedestal 19 . The ball nut 24 is screwed to the ball screw 22 . When the ball screw 22 rotates forward or backward, the ball nut 24 moves in the X direction, whereby the base 19 moves in the X direction on the pair of guide members 21 together with the ball nut 24 .

A rotation mechanism 25 is provided on the pedestal 19 . In addition, a rotating platform 26 is provided on this rotating mechanism 25 . The brittle material substrate 50 to be cut is fixed on the rotary table 26 by vacuum suction. The rotation mechanism 25 rotates the rotation platform 26 around the central axis in the vertical direction.

The support table 31 is supported above the rotary table 26 by a holding member 33 suspended from the mounting table 32 so as to be separated from the rotary table 26 and face. The support table 31 is provided with a cutter wheel 35 for forming a trigger crack on the surface of the brittle material substrate 50, an opening (not shown) for irradiating the brittle material substrate 50 with a laser beam, and a cooling nozzle for cooling the surface of the brittle material substrate 50. 37.

The cutter wheel 35 is held by the cutter wheel holder 36 so as to be able to move up and down between the position where it is pressed against the brittle material substrate 50 and the position where it is not in contact, and presses against the brittle material substrate 50 only when a trigger crack that becomes the starting point of the scribe line is formed. Then the location drops. The formation position of the trigger crack is preferably formed on the inner side of the surface side of the brittle material substrate 50 in order to suppress the preceding phenomenon that the trigger crack is generated in an unpredictable direction.

A laser output device 34 is provided on the mount 32 . The laser beam LB emitted from the laser output device 34 is reflected downward by the mirror 44, passes through the optical system held in the holding member 33, and irradiates the brittle material substrate 50 fixed on the rotary platform 26 from the opening formed in the support table 31. .

In addition, water as a cooling medium is ejected together with air from the cooling nozzle 37 of the support table 31 near the opening where the laser beam LB is emitted to the brittle material substrate 50 . The position on the brittle material substrate 50 from which the cooling medium is ejected is on the planned cutting line 51 and behind the irradiation area of the laser beam LB (see FIG. 2 ).

A pair of CCD cameras 38 , 39 for recognizing alignment marks previously engraved on the brittle material substrate 50 are provided on the mounting table 32 . Use such a pair of CCD cameras 38, 39 to detect the position deviation during the setting of the brittle material substrate 50. 50 In the case of offset Y, the slide table 12 moves by the amount of -Y.

When cutting the brittle material substrate 50 in the cutting device having such a structure, first place the brittle material substrate 50 on the rotary table 26 and fix it by suction means. Afterwards, a pair of CCD cameras 38 and 39 are used to photograph the alignment marks provided on the brittle material substrate 50 , and the brittle material substrate 50 is positioned at a predetermined position based on the photographed data as described above.

Secondly, trigger cracks are formed on the brittle material substrate 50 by the cutter wheel 35 as mentioned above. Thereafter, the laser beam LB is emitted from the laser output device 34 . The laser beam LB is irradiated substantially perpendicularly to the surface of the brittle material substrate 50 as shown in FIG. 2 via the mirror 44 . In addition, water as a cooling medium is sprayed from the cooling nozzle 37 to the vicinity of the rear end of the laser beam irradiation area. By irradiating the brittle material substrate 50 with the laser beam LB, the brittle material substrate 50 is heated in the thickness direction below the melting temperature, and the brittle material substrate 50 tends to thermally expand, but cannot expand due to local heating, and compressive stress occurs centered on the irradiated point. In addition, immediately after the heating, the surface of the brittle material substrate 50 is cooled with water, and the brittle material substrate 50 shrinks this time to generate tensile stress. Due to the action of the tensile stress, a vertical crack 53 is formed on the brittle material substrate 50 along the planned breaking line 51 starting from the triggering crack.

Afterwards, by relatively moving the laser beam LB and the cooling nozzle 37 along the planned cutting line 51 , the vertical crack 53 is extended and the scribed line 52 is formed on the brittle material substrate 50 . In this embodiment, the brittle material substrate 50 is moved by the slide stage 12, the pedestal 19, and the rotation mechanism 25 of the rotary stage 26 while the laser beam LB and the cooling nozzle 37 are fixed at predetermined positions. Of course, it does not matter if the laser beam LB and the cooling nozzle 37 are moved while the brittle material substrate 50 is fixed. Alternatively, both the brittle material substrate 50 and the laser beam LB and the cooling nozzle 37 may be moved.

Next, the cutting method of the present invention will be described. Fig. 3 is a step diagram showing an example of the cutting method of the present invention. As shown in figure (a), by moving the laser beam LB and the cooling nozzle 37 relatively along the planned cutting line 51, the vertical crack 53a starting from the trigger crack not shown in the figure is extended in the direction of relative movement, and the brittle The material substrate 50 is formed with first scribe lines 52a.

The laser beam LB used here is not particularly limited, and may be appropriately determined according to the material and thickness of the substrate, the depth of the vertical crack to be formed, and the like. When the brittle material substrate is a glass substrate, a laser beam with a wavelength of 9 to 11 μm that absorbs relatively large on the surface of the glass substrate is suitably used.

Examples of such laser beams include carbon dioxide lasers. The shape of the irradiation of the laser beam on the substrate is ideal as an elliptical shape that is elongated in the relative movement direction of the laser beam. The irradiation length L in the relative movement direction is in the range of 10 to 60 mm, and the irradiation width W is in the range of 1 to 5 mm. .

Examples of the cooling medium sprayed from the cooling nozzle 37 include water, alcohol, and the like. In addition, there is no problem in adding additives such as a surfactant within a range that does not adversely affect the brittle material substrate after use. As a cooling medium, the blowing volume is usually several ml/min. The cooling of the substrate by the cooling medium is a so-called waterjet method in which water is sprayed together with gas (usually air) from the viewpoint of rapidly cooling the substrate heated by the laser beam. The cooling area by the cooling medium is preferably circular or elliptical with a major diameter of about 1 to 5 mm. In addition, it is desirable that the cooling region is located behind the relative movement direction of the heating region by the laser beam, and the distance between the cooling region and the center point of the heating region is about several mm to several tens of mm.

The relative movement speed of the laser beam LB and the cooling nozzle 37 is not particularly limited, and may be appropriately determined according to the depth of the vertical crack to be obtained. Generally, the slower the relative moving speed is, the deeper the vertical crack will be formed. Usually, the relative speed is on the order of hundreds of mm/sec.

The depth of the vertical crack 53a constituting the first scribe line 52a is not particularly limited, but in order to increase the conditions of the irradiation laser beam for cutting the brittle material substrate in the subsequent step, such as the relative moving speed or the margin of the laser output, etc. It is ideal to have a depth of 25% or more relative to the thickness of the substrate.

Next, as shown in FIG. 3( b ), the second scribe line 52 b is formed by moving the laser beam LB and the cooling nozzle 37 relative to each other along the line 51 b perpendicular to the first scribe line 52 a. Conditions for forming the second scribed line 52b are the same as those for forming the first scribed line 52a.

Next, as shown in figure (c), the laser beam LB is irradiated again along the 2nd scribe line 52b. As a result, the vertical crack 53b extends in the thickness direction of the substrate, and the brittle material substrate 50 is cut off by the second scribe line 52b to form a breaking line 54 . In addition, the vertical crack 53 b only needs to extend to a depth at which the brittle material substrate 50 is cut without applying an external force, and does not necessarily have to reach the back side of the brittle material substrate 50 .

The irradiation conditions of the laser beam LB to extend the vertical crack 53b in the thickness direction of the substrate may be appropriately determined according to the thickness of the brittle material substrate 50 or the depth of the vertical crack 53b. The irradiation conditions are also exemplified here.

Next, as shown in figure (d), the laser beam LB is irradiated again along the 1st scribe line 52a. As a result, the vertical crack 53a extends in the thickness direction of the substrate, and the brittle material substrate 50 is cut off by the first scribe line 52a. The depth of the substrate thickness direction of the extended vertical crack 53a is the same as that of the vertical crack 53b, as long as it extends to a depth that can cut the brittle material substrate 50 without applying external force, and it does not have to reach the back side of the brittle material substrate 50. .

Here, it is important to reduce the irradiation amount of the laser beam LB to the intersection area of the first ruled line 52a and the splitting line 54 compared to other parts when irradiating the laser beam LB again along the first ruled line 52a. By reducing the irradiation amount of the laser beam LB to the intersection area of the first scribe line 52a and the cutting line 54 as described above, compared with other areas, cracking at the intersection portion which becomes the corner portion after cutting is effectively suppressed. The laser beam irradiation amount in the intersection area is preferably 50% or less of the laser beam irradiation amount outside the intersection area, more preferably 10% or less, and more preferably 0%.

In addition, in the embodiment described above, when the laser beam LB is irradiated again along the first scribed line 52a, the irradiation amount of the laser beam LB to the intersection area of the first scribed line 52a and the dividing line 54 is lower than that of other parts. However, when the laser beam LB is irradiated again along the second scribed line 52b, the irradiation amount of the laser beam LB toward the intersection area may be reduced compared to other portions. Alternatively, when the laser beam LB is irradiated again along the first scribe line 52a and when the laser beam LB is irradiated again along the second scribe line 52b, the irradiation amount of the laser beam LB to the intersection area is reduced compared with the irradiation amount of other parts. Can.

The adjustment of the irradiation amount of the laser beam LB to the intersection area of the first ruled line 52a and the second ruled line 52b can be performed, for example, by controlling the output of the laser beam. When the irradiation point of the laser beam is made into an elliptical shape elongated in the relative movement direction of the laser beam by an optical system such as a cylindrical lens, as shown in FIG. The intersection point of the lines 52 b is the center, and a predetermined range covering from the upstream side to the downstream side in the relative movement direction of the laser beam LB is defined as an area not irradiated with the laser beam LB. The irradiation amount of the laser beam LB at this time is shown in FIG. 4( b ). As can be understood from FIG. 4( b ), the irradiation amount of the laser beam LB gradually decreases from the normal irradiation amount toward the intersection point of the first scribed line 52a and the second scribed line 52b, and gradually increases back to normal irradiation after the intersection point becomes 0. quantity. As described above, by reducing the irradiation amount of the laser beam to the intersection area of the first scribe line 52a and the second scribe line 52b, the occurrence of cracks in the intersection area is suppressed.

As the region where the irradiation amount of the laser beam LB is reduced, that is, the intersection region of the first ruled line 52a and the second ruled line 52b is formed from the intersection point of the first ruled line 52a and the second ruled line 52b. Preferably, the regions each have a width of 5 mm or less on the upstream side and the downstream side in the relative movement direction of the laser beam LB.

In addition, when scanning the irradiation point of the laser beam LB with a polygonal mirror, a galvanometric mirror, a cylindrical mirror, etc., and making it into an elliptical shape that is elongated in the relative movement direction of the laser beam, the laser intensity in the irradiation point It becomes uniform and covers a predetermined range so that the laser irradiation amount can be 0. FIG. 5( a ) shows a graph showing the irradiation state of the laser beam LB over time. After the laser beam LB reaches the intersection area of the first scribe line 52a and the second scribe line 52b, it scans the intersection area to turn off the laser oscillation, but turns the laser oscillation on when it goes out of the intersection area. Thereby, as shown in FIG.5(b), the irradiation amount of the laser beam LB to the intersection area of the 1st ruled line 52a and the 2nd ruled line 52b can be made zero.

FIG. 6 shows another means of adjusting the irradiation amount of the laser beam LB to the intersection region of the first ruled line 52a and the second ruled line 52b. The means shown in this figure is to cover the intersection area of the first scribed line 52a and the second scribed line 52b with the covering member 61, so that the laser beam directed to the intersection area of the first scribed line 52a and the second scribed line 52b The irradiation amount of the light beam LB decreases. Using this means eliminates the need to control the laser oscillation on and off as in the previous embodiment, and can reduce the irradiation amount of the laser beam LB with a simple operation of placing the covering member 61 .

The covering member 61 used in the present invention is not particularly limited as long as it absorbs or reflects the laser beam LB, and examples thereof include a glass substrate, a metal plate such as aluminum, and dry ice. When a glass substrate is used, the laser beam LB is absorbed by the glass substrate, so the irradiation amount of the laser beam LB to the brittle material substrate 50 can be adjusted by its material or thickness. In addition, when a metal plate such as aluminum is used, the irradiation amount to the brittle material substrate 50 becomes zero because the laser beam LB is reflected by the metal plate.

Still another means of adjusting the irradiation amount of the laser beam LB to the intersection area of the first ruled line 52 a and the second ruled line 52 b is shown in FIG. 7 . The means shown in this figure is to cover the intersection area of the first scribe line 52a and the second scribe line 52b with liquid 62, so that the laser beam to the intersection area of the first scribe line 52a and the second scribe line 52b The amount of exposure to LB is reduced. With this means, there is no need to control the laser oscillation on and off as in the above-mentioned embodiment, and the irradiation amount of the laser beam LB can be reduced by simple operations such as dropping and coating of the liquid 62 .

The liquid 62 used in the present invention is not particularly limited as long as it absorbs or reflects the laser beam LB. For example, water, alcohol, or the like is suitably used. Adhesion of the liquid 62 to the intersection region of the brittle material substrate 50 can be performed, for example, by dripping or coating with a scrubber or the like. The adhesion amount of the liquid 62 may be appropriately determined according to the size of the intersection area, the type and output of the laser to be used, and when water is used, it is usually in the range of 0.01mL to 0.05mL.

In the embodiments described above, each of the first scribe line 52a and the second scribe line 52b is formed to divide the substrate, but in the large-area brittle material substrate 50, the first scribe line Of course, the cutting method of the present invention is also applicable to a case where a plurality of second scribe lines 52b are formed and then cut into a plurality of small-area substrates. In addition, the cutting method of the present invention is of course applicable to the case of making the intersection point at a desired angle in addition to the case of making two scribed lines perpendicular to each other.

【Example】

Example 1

Using the cutting device shown in FIG. 1, a plurality of scribed lines perpendicular to each other are formed on a chemically strengthened soda glass substrate with a thickness of 0.55 mm such that 40 intersection points are formed, and a laser beam is irradiated along one of the formed scribed lines. After cutting the substrate, a glass plate (5 mm*5 mm*thickness 0.4 mm) was placed on the intersection area of the cutting line and the other scribed line. Thereafter, a laser beam is irradiated along the other scribed line to cut the substrate into a plurality. Cutting of the glass substrate was performed using the method shown in FIG. 3 . The results are shown in Table 1. In addition, specific irradiation conditions of the laser beam are as follows.

(Laser beam irradiation conditions for forming the first scribe line 52a)

Laser Type: Carbon Dioxide Laser

Laser output: 100W

Relative moving speed: 100mm/sec

Laser spot: oval

(Laser beam irradiation conditions for forming the second scribe line 52b)

Laser Type: Carbon Dioxide Laser

Laser output: 120W

Relative moving speed: 200mm/sec

Laser spot: oval

(Laser beam irradiation conditions for laser breakage)

Laser Type: Carbon Dioxide Laser

Laser output: 320W

Relative moving speed: 1500mm/sec

Laser spot: oval

Comparative example 1

Cutting of the substrate was performed in the same manner as in Example 1 except that no glass plate was placed on the intersection region. The results are shown together in Table 1.

Table 1

"Crack": There is a crack at the intersection point

"Intersection jump": The cutting line does not extend from the intersection point to the downstream side of the relative movement direction of the laser beam

As can be understood from Table 1, compared to the method of Example 1, all of the 40 intersections were well cut, while the cutting method of Comparative Example 1 was good at only 3 intersections, and cracks occurred at the remaining 37 intersections. .

Example 2

The cutting of the substrate was carried out in the same manner as in Example 1, except that water (adhesion amount: 0.04 mL, diameter: 8 to 10 mm) was attached to the intersection area instead of the glass plate. The results are shown in Table 2. In addition, specific irradiation conditions of the laser beam are as follows.

(Laser beam irradiation conditions for forming the first scribe line 52a)

Laser Type: Carbon Dioxide Laser

Laser output: 100W

Relative moving speed: 100mm/sec

Laser spot: oval

(Laser beam irradiation conditions for forming the second scribe line 52b)

Laser Type: Carbon Dioxide Laser

Laser output: 130W

Relative moving speed: 180mm/sec

Laser spot: oval

(Laser beam irradiation conditions for laser breakage)

Laser Type: Carbon Dioxide Laser

Laser output: 240W

Relative moving speed: 1500mm/sec

Laser spot: oval

Comparative example 2

Cutting of the substrate was performed in the same manner as in Example 2 except that water droplets were not adhered to the intersection region. The results are shown together in Table 2.

Table 2

As can be understood from Table 2, compared to the cutting method of Example 2 in which water droplets are attached to the intersection area, all of the 40 intersections are good at all intersections, and only 2 of the intersections are good at the cutting method of Comparative Example 2. Cracks occurred at the remaining 38 intersections.

[industrial availability]

The cutting method of the present invention is useful for suppressing the occurrence of cracks at intersections when cutting a brittle material substrate in two directions intersecting with each other using laser light.

Claims (11)

1. A cutting method for a brittle material substrate, comprising: forming a first scribe line and a second scribe line intersecting each other on a brittle material substrate, along the first scribe line and the second scribe line. 2. A step of irradiating the laser beam while relatively moving the scribe line to extend the vertical crack and cut the substrate with the first scribe line and the second scribe line, characterized in that: When irradiating the laser beam along the first ruled line and/or the second ruled line, the amount of laser beam irradiation to the intersection area of the first ruled line and the second ruled line is lower than that of the laser beam other than the intersection area. amount decreased. 2. The method for cutting a brittle material substrate according to claim 1, wherein, The laser beam irradiation amount to the intersection area of the first ruled line and the second ruled line is 50% or less of the laser beam irradiation amount other than the intersection area. 3. The method for cutting a brittle material substrate according to claim 1, wherein, By controlling the output of the laser beam, the irradiation amount of the laser beam to the intersection area of the first scribed line and the second scribed line is reduced. 4. The method for cutting a brittle material substrate according to claim 2, wherein, By controlling the output of the laser beam, the irradiation amount of the laser beam to the intersection area of the first scribed line and the second scribed line is reduced. 5. The method for cutting a brittle material substrate according to claim 1, wherein, Covering the intersection area of the first scribed line and the second scribed line with a covering member that absorbs or reflects the laser beam reduces the irradiation amount of the laser beam to the intersection area. 6. The method for cutting a brittle material substrate according to claim 2, wherein, Covering the intersection area of the first scribed line and the second scribed line with a covering member that absorbs or reflects the laser beam reduces the irradiation amount of the laser beam to the intersection area. 7. The method for cutting a brittle material substrate according to claim 1, wherein, The intersection region of the first ruled line and the second ruled line is covered with a liquid that absorbs or reflects the laser beam, so that the irradiation amount of the laser beam to the aforementioned intersection region is reduced. 8. The method for cutting a brittle material substrate according to claim 2, wherein, The intersection region of the first ruled line and the second ruled line is covered with a liquid that absorbs or reflects the laser beam, so that the irradiation amount of the laser beam to the aforementioned intersection region is reduced. 9. The method for cutting a brittle material substrate according to any one of claims 1 to 8, wherein, The intersection region is a region having a width of 5 mm or less on the upstream and downstream sides of the relative movement direction of the laser beam from the intersection of the first ruled line and the second ruled line. 10. The method for cutting a brittle material substrate according to any one of claims 1 to 8, wherein, The first scribed line and the second scribed line are irradiated while moving the laser beam relatively to the aforementioned substrate, and after heating the aforementioned substrate until the melting temperature is lower than the melting temperature, the aforementioned substrate is blown with a cooling medium to cool the aforementioned substrate so that thermal stress formation. 11. The method for cutting a brittle material substrate according to claim 9, wherein, The first scribed line and the second scribed line are irradiated while moving the laser beam relative to the aforementioned substrate, and after heating the aforementioned substrate until the melting temperature is lower than the melting temperature, the aforementioned substrate is blown with a cooling medium to cool the aforementioned substrate so that thermal stress formation.