TWI518044B - Scribing method of brittle material substrate - Google Patents

Description

Cutting method of brittle material substrate

The present invention relates to a scribe method, and more particularly to a method of cutting a brittle material substrate which is cut along a line of cutting in which the brittle material substrates cross each other.

As a technique for dividing a brittle material substrate such as a glass substrate, a segmentation method using crack progress has been proposed. In this method, first, an initial crack is formed on the surface of the glass substrate by a cutter wheel or the like. Thereafter, a laser beam is irradiated from the initial crack to heat the substrate, thereby cooling the heated region. Thereby, the initial crack is used as a trigger to cause the crack to progress, and the cutting groove is formed along the line to be cut.

This cutting method is disclosed in Patent Document 1. In the method of Patent Document 1, an initial crack is formed at the starting point of the processing of the substrate, and then the spot of the elliptical shape is scanned along the line to be cut. Thereby, the crack progresses continuously along the planned cutting line.

(previous technical literature) (Patent Literature)

Patent Document 1: Japanese Laid-Open Patent Publication No. 2003-137578.

Patent Document 1 describes (paragraph 0054) that, when the initial crack is formed, a high-output laser beam is condensed on the surface of the substrate for processing. A hole from which a crack is made. However, there is no detailed description of the hole that is the initial crack.

However, a cover glass for a touch panel is formed by dividing one mother substrate. More specifically, a predetermined number of cutting lines intersecting in the X and Y directions are set on the mother substrate, and a cutting groove is formed along the plurality of predetermined cutting lines. That is, the mother substrate is cross-cut and a plurality of cover glasses are obtained by dividing along the formed cutting grooves. Each of the divided cover glass has a curved shape formed by four corner portions.

However, it takes time to perform the polishing process in which the corner portions of the divided glass are curved.

An object of the present invention is to provide a dicing method which can stably form a dicing groove and perform a polishing process at a corner portion of a post-production step, particularly when cross-cutting along a line to be cut which intersects each other.

The method of cutting a brittle material substrate according to the first aspect of the invention is a method of cutting along a line to be cut in which the brittle material substrates intersect each other, and includes a first step and a second step. In the first step, at the intersection of the intersecting cutting lines, a through hole having a four-edge portion extending through the substrate and extending along the intersecting cutting line is formed. In the second step, the crack progresses along the planned cutting line with the through hole as a starting point.

In this method, a through hole which is an initial crack is formed at the intersection of the planned cutting line. The through hole has a delay along a line of cut of the intersection Stretched 4 ribs. Thereafter, the crack progresses along the line to cut with the respective rib portions of the through hole as a starting point.

Here, since the through hole has a rib extending along the line to be cut, in the second step, the crack easily progresses along the line to be cut, and the desired dicing groove can be stably formed. Further, since the through holes are formed in the portions where the planned cutting lines intersect, that is, the portions corresponding to the four corner portions of the divided substrate, the predetermined polishing amount of the four corner portions can be reduced after the division.

According to a second aspect of the invention, in the method of the first aspect of the invention, the through hole formed in the first step is formed between the adjacent two ribs and expanded toward the inside of the hole. The star shape of the four edges of the curved arc shape.

Here, the through hole is a star shape composed of four rib portions and four edge portions to which the rib portions are tied, and the four edge portions are curved in an arc shape so as to expand toward the inside of the hole. Accordingly, the four corner portions of the divided substrate are arc-shaped at the time of division. Therefore, when the four corner portions are polished into a curved shape in the step after the division, the predetermined polishing amount of each corner portion can be reduced.

According to a third aspect of the invention, in the method of the first aspect of the invention, the through hole formed in the first step has a linear shape formed between two adjacent ribs. The rectangular shape of the part.

Here, the through holes are rectangular. Therefore, although it is not the extent of the second invention, when the four corner portions are polished into a curved shape in the step after the division, the predetermined polishing amount of each corner portion can be reduced.

The method for cutting a brittle material substrate according to the fourth aspect of the invention is the first to the first In any of the methods of the invention, in the first step, the through holes are formed by a green laser.

In the method of cutting a brittle material substrate according to the fifth aspect of the invention, in the method of any one of the first to third aspects, in the second step, the laser beam is irradiated along the planned cutting line of the substrate, and is cooled by cooling. The heated region progresses the crack along the planned cutting line.

According to a fourth aspect of the invention, in the method of the fourth aspect of the invention, in the method of the fourth aspect, the laser beam is irradiated with laser light along a line to be cut of the substrate, and the heated region is cooled. The crack progresses along the cut line.

In the present invention according to the above, when the brittle material substrate is cross-cut, the dicing groove can be stably formed, and the polishing processing at the corner portion of the post-production step can be facilitated.

[Device configuration]

Fig. 1 is a view showing a schematic configuration of a cutting device for carrying out the method according to an embodiment of the present invention. In addition, in the first drawing, the state after the first step is displayed, that is, the through hole is formed in the glass substrate, and the cutting process belonging to the second step is performed.

The cutting device 1 is, for example, a device for dividing a mother glass substrate into a plurality of glass substrates used for a cover glass of a touch panel. Here, the glass substrate is mainly a chemically strengthened glass in which a reinforcing layer is formed on the surface. The chemically strengthened glass has a surface by ion exchange treatment A strengthening layer with compressive stress.

<cutting device>

The cutting device 1 includes an illuminating unit 2, a cooling unit 3, and a moving unit (not shown) for illuminating a laser beam toward the glass substrate G. The cooling unit 3 is for The refrigerant supplied from the refrigerant source of the unillustrated form is ejected through a nozzle (Nozzle) 4 to form a cooling point CP. The moving portion is such that the nozzle 4 of the irradiation unit 2 and the cooling unit 3 is along the glass substrate G. The cutting planned line SL set on the glass substrate G is relatively moved.

The illuminating unit 2 has a laser oscillator (for example, a CO ₂ laser) that illuminates the laser beam LB, and irradiates the laser beam LB onto the glass substrate G via an optical system to serve as a beam spot LS. .

<through hole forming device>

In the dicing apparatus 1, an illuminating part (not shown) for forming a through hole is provided. The illuminating portion for forming the through hole is a through hole for forming a starting point of crack growth when the dicing groove is formed in the glass substrate G. The illuminating portion for forming the through hole is provided with, for example, a laser oscillator and an optical system for emitting a green laser.

[Cutting method]

Here, in order to compare with the method of the present invention, the processing sequence of the cover glass of the conventional touch panel will be briefly described using FIG. First, the mother substrate (a) is prepared, and an initial crack (not shown) is formed on the mother substrate G at the end portion of the substrate by a cutter roller or the like. Then, the mother substrate G is irradiated and scanned along the line to cut, and the laser beam is further cooled to form the cutting groove SG(b). Thereafter, a dividing force is applied to both sides of the dicing groove SG, whereby the mother substrate G is divided into a plurality of glass substrates. Next, the corner portion of the divided glass substrate is polished (c, d) so as to have a curved shape.

Next, the processing sequence of an embodiment of the present invention will be described using FIG.

First, in the first step, a plurality of through holes H(b) penetrating from the surface of the substrate to the back surface are formed on the mother substrate G(a). The through holes H are formed on the substrate by, for example, irradiating a green laser. Each of the through holes H is formed at an intersection of a planned cutting line in the X direction and the Y direction (see FIG. 3) orthogonal to each other. Further, as can be seen from Fig. 3(b), each of the through holes H is a star shape having a ridge extending along a line to be cut. More specifically, as shown in the enlarged third figure, each of the through holes H is a star shape having four ribs 11a to 11d and four edge portions 12a to 12d, and the four ribs 11a to 11d It is extended along the cutting line SL, and the four edge portions 12a to 12d are formed between the adjacent two ribs 11a-11b, 11b-11c, 11c-11d, 11d-11a and toward the inside of the hole. The shape of the expansion is curved in an arc shape.

Next, in the second step, as shown in FIGS. 1 and 3, the laser beam LB is irradiated from the irradiation unit 1. The laser beam LB is irradiated onto the mother substrate G as a beam spot LS. Next, the laser beam LB emitted from the irradiation unit 2 is relatively moved along the planned cutting line SL and the mother substrate G. The mother substrate G is heated by the beam spot LS to a temperature lower than the softening point of the mother substrate G. Further, the cooling point CP is caused to follow the moving direction of the beam spot LS.

According to the above, it is heated by the irradiation of the laser beam LB Although the compressive stress is generated in the vicinity of the beam spot LS, the cooling point CP is formed by the injection of the cold coal in a short time, so that a tensile stress effective for the formation of a vertical crack is generated. By the tensile stress, a vertical crack is formed along the line to cut SL as a starting point formed in the through hole H of the mother substrate G, and a desired cutting groove (c) is formed.

Thereafter, a dividing force is applied to both sides of the dicing groove SG, whereby the mother substrate G is divided into a plurality of glass substrates. Next, the corner portion of the divided glass substrate is polished (d, e) so as to have a curved shape.

Here, since the through hole H is formed in a star shape having an arc-shaped edge portion that is curved so as to expand toward the inside of the hole, the four corner portions of each of the divided substrates are chamfered into a curved shape. . Therefore, the amount to be polished (predetermined amount of polishing) in the polishing step is extremely small, and the polishing operation can be easily and in a short time.

[Other examples of through holes]

The shape of the through hole is not limited to the star shape as shown in Fig. 3. For example, as shown in FIG. 4, it may be a rectangle. Specifically, the through hole H' shown in Fig. 4 is a rectangular shape having four ribs 21a to 21d and four rim portions 22a to 22d which are ordered along the cutting line. The line SL extends, and the four edge portions 22a to 22d are linearly formed between the adjacent two rib portions 21a-21b, 21b-21c, 21c-21d, and 21d-21a.

In such a through hole H', although the predetermined amount of polishing at the corner portion of the substrate is larger than that of the through hole H of the star shape, the amount of polishing can be reduced as compared with the conventional processing method.

[Experimental example]

In the first table, it is shown that the through-holes of the three types of shapes are formed on the mother substrate by the green laser, and thereafter the evaluation of the cutting grooves when the laser output is changed and cut is performed. In addition, the glass substrate here is a soda-lime glass (Soda-Lime Glass).

○: can be cut

Bend: Shows the maximum offset from the cut line, in [μm].

In the above experimental examples, the respective conditions of the first step (formation of the through holes) and the second step (cut) are as follows.

[Step 1]

In the first step, the laser beam is moved in the height direction (Z-axis direction) while rotating the light-converging point, and processing is performed. That is, the through hole is formed while the laser spot is spirally moved.

Wavelength: 532nm

Laser output: 5W

Repeat frequency: 20kHz

Convergence point rotation radius: 500rps

Z axis moving distance: 40μm

Scanning speed: 30mm/s

[Step 2]

Wavelength: 10.6μm

Laser output: 120 to 200W

Repeat frequency: 10kHz

Scanning speed: 250mm/s

Further, an enlarged photograph of the vicinity of the through hole before the display division in the case where the laser output of the first table is 140 W and an enlarged photograph of the curved after the division are shown in Fig. 5. In Fig. 5, (a) is an example of a case where a circular through hole having a diameter of 4 mm is formed and a cutting process and a division are performed thereafter, and (b) is a rectangular through hole having a side of 4 mm. An example of the case where the cutting process and the division are performed thereafter, (c) is an example in which a through hole having a star shape of 4 mm on one side is formed, and then cutting processing and division are performed. In each of the figures, the upper section shows the appearance of the crack progression (cutting mark) before the break, and the lower section shows the curvature of the cut after the division.

It can be seen from the above experimental results that although the shape of the through hole can be cut, it can be known that the bending becomes large in the case where the shape of the through hole is circular, and the bending is performed in the case of a rectangle and a star. Become smaller. That is, it can be known that the more the shape of the portion of the planned cutting line of the through hole which is the starting point of the cutting is the prism shape (sharp angle), the more the bending of the cutting is reduced.

[Other Embodiments]

The present invention is not limited to the embodiments described above, but can be Various modifications or corrections are possible within the scope of the invention.

In the above-described embodiment, the case where the dicing groove is formed in the second step (laser irradiation and cooling treatment) has been described, but the present invention can be similarly applied to the case where the glass is divided by the second step. .

1‧‧‧ cutting device

2‧‧‧ Department of Irradiation

3‧‧‧ Cooling Department

4‧‧‧ nozzle

11a to 11d‧‧‧through the edge of the hole

12a to 12d‧‧‧ the edge of the through hole

21a to 21d‧‧‧through the edge of the hole

22a to 22d‧‧‧ the edge of the through hole

CP‧‧‧cooling point

G‧‧‧ mother substrate

H, H’‧‧‧through holes

LB‧‧‧Laser beam

LS‧‧‧beam point

SG‧‧ cutting trench

SL‧‧‧ cutting line

Fig. 1 is a schematic configuration diagram of a cutting device for carrying out a cutting method according to an embodiment of the present invention.

FIGS. 2(a) to (d) are views showing a processing sequence of a cover glass of a conventional touch panel.

Fig. 3 (a) to (e) are views showing a processing sequence of a cover glass of a touch panel according to an embodiment of the present invention.

Fig. 4 is a view showing another example of the through hole.

Fig. 5 (a) to (c) are enlarged photographs showing the crack progression (cut marks) after the cutting processing of the three types of through holes and the bending of the cut after the division.

Reason: The entire schema [Fig. 3 (a) to (e)] must be used to show the complete technical features.

11a to 11d‧‧‧through the edge of the hole

12a to 12d‧‧‧ the edge of the through hole

G‧‧‧ mother substrate

H‧‧‧through hole

SG‧‧ cutting trench

Claims (6)

A method for cutting a brittle material substrate, which is a method for cutting a brittle material substrate which is cut along a cutting line intersecting the brittle material substrate, comprising: a first step, at an intersection of the intersecting cutting lines, A through hole that penetrates the substrate and has four ribs extending along the intersecting cutting line is formed; and a second step is such that the crack progresses along the planned cutting line with the through hole as a starting point. The method for cutting a brittle material substrate according to the first aspect of the invention, wherein the through hole formed in the first step has a shape formed between two adjacent ribs and expanded toward the inside of the hole. The star shape of the four edges of the curved arc shape. The method of cutting a brittle material substrate according to the first aspect of the invention, wherein the through hole formed in the first step has four linear shapes formed between two adjacent ribs. The rectangular shape of the rim. The method of cutting a brittle material substrate according to any one of claims 1 to 3, wherein in the first step, the through hole is formed by a green laser. The method of cutting a brittle material substrate according to any one of the preceding claims, wherein, in the second step, the laser beam is irradiated along the line to be cut of the substrate, and is heated. The crack progresses along the planned cutting line by cooling the heated region. The method for cutting a brittle material substrate according to claim 4, wherein in the second step, the laser beam is irradiated along the cutting line of the substrate to be heated, and the heated region is cooled. The crack progresses along the cut line.