TWI454330B - A method for processing a brittle material substrate and a laser processing apparatus for use in the method - Google Patents

Description

Method for processing brittle material substrate and laser processing device therefor

The present invention relates to a method for forming a crack by locally irradiating a substrate of a brittle material such as glass, tantalum, ceramics, or a semiconductor onto a predetermined line to discharge laser light, and then locally cooling the container to form a cooling agent. The term "processing" as used herein refers to the process of forming a thermal stress distribution on a substrate by heating and cooling to form a crack on the substrate, but also includes forming the formed crack from the surface of the substrate to the back surface so as to be completely broken. In the case, a deep crack (cracking of 80% or more of the thickness of the substrate) is formed in the predetermined line to be processed so as to be in a state of being completely broken.

Conventionally, as a method of breaking (cutting) a brittle material, that is, a glass substrate, it is known that, for example, Patent Document 1 and Patent Document 2 locally heat and cool a substrate by thermal stress (compression stress and tensile stress) generated at that time. A method of processing in which a crack is formed in a desired direction from an initial crack (trigger) formed in advance at an end portion of a substrate, and a scribe line or a complete rupture (when the thickness is extremely thin) is formed on the substrate.

Specifically, the laser beam is used as a heat source, and the substrate held on the platform is moved relative to the laser beam, so that the laser beam is locally irradiated and heated along the predetermined line of the substrate, and then ejected from the nozzle of the cooling unit. Refrigerant. At this time, the stress distribution due to the compressive stress generated by the heating and the tensile stress generated by the rapid cooling causes the crack to progress in the direction of the predetermined line to form a score line.

Thereafter, in addition to being completely broken when the substrate is extremely thin, the substrate is bent to break the substrate by pressing the breaking bar along the scribe line (crack) or crimping the rotating roller.

Patent Document 1: Japanese Laid-Open Patent Publication No. 2004-182530

Patent Document 2: Japanese Patent Laid-Open Publication No. 2005-263578

However, in the conventional method described above, when the external force is applied to bend the substrate to be divided by heating and cooling, the end faces formed by being separated may be pressed against each other, and the cutting line may not be accurately divided along the predetermined line. In addition, there are also problems of roughening the section.

In view of the above problems, the present invention has an object of providing a method for breaking a substrate which can be accurately separated along a predetermined line L by solving the problem.

After reviewing the above-mentioned problems, it was found by the inventors' repeated experiments that the end faces formed by the breaking were caused by the following points. Fig. 6 is a cross-sectional view showing the state of the substrate which has been cooled by the injection of the refrigerant immediately after the partial heating. In addition, for the convenience of explanation, exaggeration shows cracks and the like.

After the substrate W is locally heated by the laser beam, if the heated portion is quenched by the refrigerant from the nozzle 13 of the cooling device, tensile stress is generated. By this tensile stress, crack 11 is generated as shown in Fig. 6(a). The opening of the crack 11 is closed as it leaves the cooling point where the refrigerant is ejected, and becomes a blind crack 12 which is visually invisible as shown in Fig. 6(b). The blind crack 12 is a region in which tensile stress is generated by cooling, and the temperature is moderated as time passes. When the surface temperature rises again, it becomes a compressive stress, and the cracked surface is compressed and the crack is closed. If an external force is applied in a state where such a blind crack (the opening of the crack that has once occurred is closed again and is invisible to the eye but there is still a crack in the inside), the substrate is bent to be broken. The opening of the crack has a compressive stress remaining and is closed, so that a large external force is required, and if it is to be forced to break, the end faces formed by the breaking will press each other. This compressive stress is a factor that cannot be accurately separated along the predetermined line.

Therefore, in order to achieve the above object, the following technical means are employed in the present invention. That is, the processing method of the brittle material substrate of the present invention is a heating step of causing the substrate to generate local compressive stress by heating the laser beam while being relatively moved along the predetermined line of the brittle material substrate. a cooling step in which a cooling region formed by injecting a refrigerant in a vicinity of a heated region follows a laser beam while locally cooling the brittle material substrate to cause tensile stress to be generated and the crack progresses along a predetermined line to be broken, When the tensile stress remains and the opening of the crack is opened, an external force is applied to the region where the opening of the crack is generated, so that the crack penetrates in the thickness direction.

Here, it is preferable that the position at which the external force is applied in the breaking step is disposed within a range of 20 mm from the cooling center of the cooling region generated by the cooling step to the rear side in the moving direction of the cooling region and 5 mm toward the front side in the moving direction of the cooling region. In particular, it is preferable that the opening portion of the crack due to cooling is maximized, and the position from the cooling center (cp) of the substrate to the direction in which the cooling region moves in the opposite direction is 0 to 10 mm. .

According to the processing method of the present invention, since the position at which the external force is applied in the breaking step is such that the crack generated by the rapid cooling in the cooling step does not become a blind crack and the opening of the crack is opened, the external force is slightly applied. That is, as long as the area where the opening of the crack is opened by the external force is slightly bent, the crack can be smoothly penetrated and broken. Thereby, the phenomenon in which the end faces formed by the breakage are pressed against each other can be eliminated, and the line can be accurately divided along the line to be divided, and a smooth and beautiful cross section can be obtained.

In the present invention, the roller pressed against the substrate can be used as a means for applying an external force in the breaking step, and the roller is disposed on the opposite side of the laser irradiation surface of the substrate, and an external force is applied by the pressure roller.

Thereby, the region where the opening of the crack is opened can be surely bent, and the crack can be smoothly penetrated and separated.

Hereinafter, the details of the processing method of the present invention will be described in detail based on the drawings showing the embodiments thereof.

Fig. 1 is a schematic perspective view showing an example of a laser processing apparatus for carrying out the processing method of the present invention, and Fig. 2 is a view for explaining a processing method.

The laser processing apparatus includes a divided platform 1 on which a glass substrate W is placed. The stage 1 has a flat upper surface 2 on which the substrate W is placed, and a plurality of air suction holes 3 are provided in the upper surface 2. The air suction hole 3 sucks and holds the substrate W placed thereon, and communicates with an air suction pump (not shown) through a branch pipe (not shown) provided inside the stage 1. Further, a transfer robot 5 that picks up and transports the substrate W placed on the stage 1 through the suction cup 4 is provided.

Further, a laser irradiation mechanism 6 is provided as a heating means for causing the substrate W placed on the stage 1 to be processed along the predetermined line to cause local compressive stress to be generated, thereby following the laser The heating region (laser spot) generated by the illuminating mechanism 6 is cooled by the refrigerant to cool the vicinity of the heating region to generate tensile stress and to cause the crack to progress along the breaking predetermined line, and the tensile stress therein In the residual period, a breaking mechanism 8 that applies an external force to the vicinity of the cooling region (the region where the opening of the crack is generated) so that the crack penetrates in the thickness direction.

The cooling mechanism 7 includes a nozzle 7a that ejects a refrigerant from the tip end. Further, the breaking mechanism 8 includes a roller 8a disposed on the lower side of the substrate W, and the roller 8a is pressed from below by the gap of the divided platform 1, and the substrate is pressed and divided. Further, it is preferable that the receiving roller 8b having a concave peripheral surface is disposed on the upper side of the substrate W with respect to the roller 8a.

The laser irradiation mechanism 6, the cooling mechanism 7, and the breaking mechanism 8 are formed so that the laser irradiation mechanism 6 is sequentially arranged on the straight line and held by the common holding member, and can be relatively loaded by a driving mechanism (not shown). The stage 1 on which the substrate W is placed is moved in the arrangement direction.

The roller 8a of the breaking mechanism 8 is disposed in a region where the crack 10 (see FIG. 4) generated by the rapid cooling of the refrigerant from the nozzle 7a does not become a blind crack and the opening of the crack 10 is opened.

Specifically, when the thickness of the glass substrate W to be processed is about 0.4 to 1.1 mm and the conveying speed of the substrate W is 50 mm/sec to 500 mm/sec, the roller 8a is disposed at the center of the cooling point from the nozzle 7a. Cp (Fig. 2) is a range of 20 mm on the rear side and 5 mm on the front side in the moving direction in the direction opposite to the moving direction (arrow direction) of the nozzle 7a with respect to the substrate W.

In particular, the position of the opening of the crack 10 which is generated by the cooling is most preferably opened, from the center cp of the cooling point (Fig. 2) to the direction in which the nozzle 7a moves in the opposite direction with respect to the substrate W, and then the side is 0 to 10 mm. The location within the range is appropriate. Incidentally, in the past, the idea of scribing and breaking should be carried out in individual steps. It is considered that it is preferable to not impart vibration as much as possible when the roller is broken, and it is considered that the substrate W is sufficiently cooled and the crack is sufficiently progressed toward the thickness direction of the substrate. Preferably, the breaking step is preferably performed, and the roller is disposed at a position sufficiently away from the refrigerant ejection position (20 mm or more from the center cp of the cooling point to the rear side).

In addition, when the roller 8a is disposed at a position separated from the center cp of the cooling point by 5 mm from the front side of the nozzle 7a in the moving direction with respect to the substrate W, the effect of allowing crack penetration is not observed.

Second, for the processing action description. When the substrate W is processed along the line dividing line L, the predetermined line L positioned as the substrate W comes to a predetermined processing position in the laser processing apparatus while being held by the stage 1. Thereafter, the laser beam is irradiated to the substrate W while the laser irradiation mechanism 6 (holding member 9) is relatively moved along the predetermined line L, and as shown in FIG. 3, the substrate W is subjected to a local compressive stress field P1. Next, as shown in FIG. 4, the vicinity of the area where the laser beam has been heated by the laser beam (so that P1 moves slightly inside the substrate) is quenched by the refrigerant jet from the nozzle 7a of the cooling mechanism 7. The tensile stress P2 is generated.

Thereby, the crack 10 is formed along the breaking planned line L (FIG. 1). Further, as shown in Fig. 5, the roller 8a of the breaking mechanism 8 is raised, and the region where the crack 10 is generated by the cooling step is bent, and the crack depth is infiltrated to 100% (completely broken) of the plate thickness to 80%.

At this time, since the pressure contact position of the roller 8a of the breaking mechanism 8 is a region in which the crack 10 caused by the rapid cooling of the nozzle 7a does not become a blind crack and the opening of the crack 10 is opened, it is only necessary to make the roller 8a slightly By pressing, that is, the region where the opening of the crack 10 is opened by the roller 8a is slightly bent, and the crack can be smoothly penetrated. Thereby, the phenomenon in which the end faces formed by the breakage are pressed against each other can be eliminated, and the line can be accurately divided along the line to be divided, and a smooth and beautiful cross section can be obtained.

The present invention has been described with reference to the preferred embodiments of the present invention. However, the present invention is not necessarily limited to the embodiments described above, and may be appropriately modified or changed without departing from the scope of the invention.

[Industrial availability]

The processing method of the present invention can be utilized for processing a substrate made of a brittle material such as a glass substrate.

W. . . Substrate

L. . . Breaking line

1. . . platform

6. . . Laser irradiation mechanism

7. . . Cooling mechanism

7a. . . nozzle

8. . . Broken mechanism

8a. . . Wheel

10. . . Crack

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view showing an example of a laser processing apparatus for carrying out the processing method of the present invention.

Fig. 2 is a view for explaining the processing method of the present invention.

Fig. 3 is an enlarged cross-sectional view showing the state of generation of thermal stress during processing in the present invention, showing a state in which compressive stress is generated.

Fig. 4 is an enlarged cross-sectional view showing a state in which thermal stress is generated during processing in the present invention, showing a state in which tensile stress is generated.

Fig. 5 is an enlarged cross-sectional view showing a state in which an external force is applied.

Fig. 6 is a cross-sectional view showing the state of the substrate immediately after the cooling of the refrigerant after the laser heating.

W. . . Substrate

L. . . Breaking line

1. . . platform

2. . . Above

3. . . Air suction hole

4. . . Suction cup

5. . . Transfer robot

6. . . Laser irradiation mechanism

7. . . Cooling mechanism

7a. . . nozzle

8. . . Broken mechanism

8a. . . Wheel

8b. . . Undertake roller

9. . . Holding member

Claims (5)

A method for processing a substrate of a brittle material, which comprises heating a substrate by locally moving a laser beam by relatively moving a laser beam along a predetermined line of a brittle material substrate, thereby causing a localized compressive stress to be heated by the substrate. The cooling region formed by spraying the refrigerant in the vicinity of the region follows the cooling beam while locally cooling the brittle material substrate to generate tensile stress and to cool the crack along the predetermined line, and to apply an external force to the substrate. a step of breaking the crack in the thickness direction; wherein the position of the external force applied in the breaking step is within the range of the cooling region and is 20 mm from the cooling center of the cooling region to the rear side of the moving direction of the cooling region The area in the direction of movement is within 5 mm of the front side. The method for processing a brittle material substrate according to claim 1, wherein the roller is disposed on the opposite side of the laser irradiation surface of the substrate in the breaking step, and an external force is applied by the pressure roller. A laser processing apparatus comprising: locally compressing a substrate by heating a laser beam while being relatively moved from above the substrate by a predetermined dividing line of a brittle material substrate placed on the platform; a laser irradiation mechanism; and a cooling region formed by injecting a refrigerant near the heated region to follow a laser beam to locally cool the brittle material substrate to generate tensile stress and to cause the turtle along the predetermined line a cooling mechanism for cracking progress; the gap is divided into two sides by a gap for exposing a lower side of the planned dividing line of the substrate, and is provided from the lower side of the substrate a breaking mechanism for applying an external force to infiltrate a crack in a thickness direction; the cooling mechanism having a nozzle for injecting a refrigerant, in a range of a cooling region from which the refrigerant is sprayed, and a cooling center from the cooling region to a nozzle opposite to the substrate The breaking mechanism is disposed in a range in which the moving direction is the opposite side, that is, the rear side 20 mm and the moving direction front side 5 mm. The laser processing apparatus according to claim 3, wherein the breaking mechanism is constituted by a roller that moves along the gap with respect to the platform and simultaneously presses a lower surface of a predetermined dividing line of the substrate. The laser processing apparatus according to claim 4, wherein the breaking mechanism further includes a receiving roller having a concave peripheral surface with respect to a position of the roller above the substrate.