TWI380963B - Method for processing brittle material substrates - Google Patents

Description

Method for processing brittle material substrate

The invention relates to a method for processing a brittle material substrate, which is to scan a laser for a brittle material substrate for local heating, and secondly to cool along a heating portion, thereby utilizing thermal stress generated between the substrate surface and the substrate to form a limited depth. Cracks. The present invention relates to a method for processing a brittle material substrate, which irradiates a first laser beam along a predetermined line of a scribe line set on a substrate, forms a scribe line formed by a crack of a limited depth on the substrate, and secondly irradiates the second The laser beam is so second that the scribe line penetrates deeper or is completely broken.

The brittle material substrate herein refers to a glass substrate, a ceramic of a sintered material, a single crystal germanium, a semiconductor wafer, a sapphire substrate, a ceramic substrate, or the like.

A laser scribing method for irradiating a laser beam such as a glass substrate with a laser beam, scanning a beam spot formed on the substrate, heating the wire, and then blowing the refrigerant to cool it immediately after heating The generation of debris is reduced more than mechanical machining such as using a cutter wheel, and the strength of the end face can be improved.

Therefore, in various processes required for dividing a glass substrate such as a flat panel display, laser scribing is used.

In general, in the laser scribing process, an imaginary line (referred to as a scribe line) to be divided therefrom is set. Then, an initial crack is formed by the cutter wheel being equal to the start end of the predetermined line of the scribe line, and the beam spot and the cooling point (the area of the jet refrigerant) are scanned along the predetermined line of the scribe line from the position of the initial crack formed at the start end. . At this time, as a result of the stress gradient generated in the vicinity of the predetermined line of the scribe line, a linear crack is formed (see Patent Document 1, Patent Document 2, and Patent Document 3).

Further, in the linear crack formed by scanning the laser beam on the brittle material substrate, the front end in the depth direction of the crack does not reach the "crack of a limited depth" on the back surface of the substrate, and the crack reaches the back surface of the substrate to break the substrate once. "through crack" (see, for example, Patent Document 2).

The cut formed by the former "crack of limited depth" is called a scribe line, and the dividing line of the latter through the crack is called a full cut line. These are formed in different ways.

Figure 7 is a cross-sectional view showing the substrate in a manner of forming a finite depth in a schematic manner. That is, the compressive stress HR is generated on the substrate GA as shown in Fig. 7(a) by the laser heating performed first. Next, by the cooling after heating, a tensile stress CR is generated on the surface of the substrate as shown in Fig. 7(b). At this time, the compressive hard force HR moves inside the substrate due to the movement of heat, and the internal stress field Hin is formed. As a result, as shown in FIG. 7(c), a stress gradient in the depth direction is generated to form a crack Cr.

In the condition of forming the crack Cr by the above method, in order to prevent the compressive stress field Hin existing inside the substrate from further penetrating into the depth direction of the crack Cr, the crack Cr stops before the compressive stress field Hin inside the substrate, in principle, the crack Cr That is, a limited depth is formed. Therefore, in order to completely break the substrate, it is necessary to further perform the cracking treatment after forming the scribe line having the finite depth of the crack Cr. On the other hand, the processed end surface of the crease of the crack Cr is very beautiful (the surface unevenness is small) and the straightness is excellent, and it is an ideal state as a machined end surface.

Fig. 8 is a perspective view (Fig. 8(a)) and a plan view (Fig. 8(b)) showing a substrate in which a through crack is formed in a schematic manner. That is, the compressive stress HR is generated on the surface of the substrate by the beam spot BS of the laser beam scanned from the position of the initial crack TR. At the same time, a tensile stress CR is generated on the surface of the substrate by the cooling point CS located behind the beam spot BS. As a result, a stress gradient in the front-rear direction is formed on the scanning line (on the predetermined line L), and the stress gradient causes a force to crack the left and right sides of the substrate in the scanning line direction to form a through crack, thereby breaking the substrate. .

In the case of forming such a "through crack", there is an advantage that the substrate can be broken (completely cut) without performing a cracking treatment, and it is preferable to use this method for disconnection depending on the processing application. In other cases, compared with the processed end face of the above-mentioned scribing, there is a case where the straightness of the processed end face of the full cut line is impaired, and the degree of beauty of the end face of the full cut line (surface irregularity) is as described above. The dash is also inferior to its quality.

In addition, the scribing or full cutting line is formed by laser scribing, depending on heating conditions (laser wavelength, irradiation time, output power, scanning speed, etc.), cooling conditions (refrigerant temperature, blowing amount, spray) Blowing position, etc.), the thickness of the substrate, and the like. In general, when the thickness of the glass substrate is thin, it is easier to become a full cutting line than the thicker one, and the process tolerance for forming the processing conditions of the scribe line is relatively narrow. Further, the more extreme the conditions of heating the substrate or rapidly cooling the substrate, the more likely the formation of the full cutting line is.

In the case where the glass substrate or the like is to be subjected to a division process excellent in the end surface quality, the heating condition and the cooling condition in which the entire line is not formed are selected, and the laser scribing is performed, and then the cracking is performed. deal with.

In the cracking treatment method after the laser scribing process, there is a mechanical cracking treatment, that is, a cracking tool or the like is pressed against the scribing to apply a bending moment. In the case of mechanical rupture treatment, debris is generated when a large bending moment is applied to the substrate. Therefore, in the process of avoiding the generation of debris, it is necessary to form a deep scribe line as much as possible, and only apply a small bending moment to perform the cleavage treatment.

Therefore, in the past, the following laser cracking treatment was performed: the second laser irradiation was performed along the scribe line formed by laser scribing, so that the crack of the finite depth penetrated deeper (in this case, the crack is further broken). Or the crack is infiltrated into the back surface to be broken (see, for example, Patent Documents 1 to 3).

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

Patent Document 2: Japanese Laid-Open Patent Publication No. 2006-256944

Patent Document 3: WO2003/008352

As described above, the laser scribing process for forming the scribe line is performed by the first laser irradiation, and the laser rupture process is performed by the second laser irradiation, thereby suppressing the generation of debris. Disconnected processing. However, when the laser scribing process, that is, the scribing formed by the first laser irradiation, is shallow, it is difficult to cause the crack to reach the back surface of the substrate by the subsequent laser chipping process. Therefore, in order to completely break the substrate by the laser cracking process, a deeper scribe line must be formed first during the laser scribing process.

Moreover, even if the substrate is not completely broken by the laser rupture process, a deep scribe line is formed in the laser scribing process, and it is easier to form a deeper in the subsequent laser rupture process. Dashing is therefore ideal.

Further, when it is desired to form a deep scribe line which is deeper than the prior art by laser scribing, it is necessary to change the heating condition or the cooling condition in the case where the scribe line is conventionally formed. Specifically, it is necessary to increase the laser output to increase the heat input amount of heating, or increase the amount of refrigerant sprayed during cooling, and set an extreme condition that is more likely to generate a temperature difference in the depth direction than in the past, so as to increase the substrate generation. The stress gradient in the depth direction.

However, according to the processing steps of the conventional laser scribing process, the heating conditions and the cooling conditions for increasing the stress gradient are not able to form a deep scribe line by the first laser irradiation, but the crack is penetrated. The substrate (moving to form a through crack) forms a full cut line. That is, although the light gradation line can be easily formed by appropriately selecting the heating condition or the cooling condition at the time of laser scribing processing, even if a deep scribe line is to be formed, the heating condition or the cooling condition is changed to be more conventional. The conditions used are slightly extreme, that is, the range of heating conditions or cooling conditions that can be set does not exist or the range (process tolerance) that can be set even if it exists is narrow and unstable, resulting in sudden migration to formation. It is difficult to form the desired deep scribe line by completely cutting the condition of the line.

Furthermore, in addition to the problem of moving to the full cut line, problems arise that are prone to "first move". In the vicinity of the start end of the scribe line L, the initial crack TR formed by the beam spot BS is heated in the vicinity of the start end of the scribe line L, and the heating region of the beam spot BS is used as a starting point. The phenomenon of crack K is formed in an uncontrollable direction in front of the beam spot. When the "first" phenomenon occurs, the scribe line along the predetermined line L of the scribe line cannot be formed, and the straightness of the scribe line is significantly impaired.

When the deeper scribe line is to be formed and the heating condition or the cooling condition is adjusted to a more extreme heating condition or cooling condition than before, the frequency of the above-mentioned "preemptive" phenomenon is also increased.

Accordingly, a first object of the present invention is to provide a processing method capable of forming a scribe line formed by a scribe line having a limited depth to have a sufficient depth from a conventional technique.

In addition, a second object of the present invention is to provide a processing method capable of stably forming a scribe line by providing a process tolerance that can form a heating condition or a cooling condition in which a scribe line can be formed without a full cut line.

Further, a third object is to provide a processing method which is difficult to generate a "first" phenomenon.

Moreover, an object of the present invention is to provide a method for processing a substrate of a brittle material, which can stably perform a process of forming a scribe line by laser scribe line processing, and further performing a laser cleavage process to completely break the substrate or form a deeper Processing of cracks. Further, an object of the present invention is to provide a method for processing a brittle material substrate which can stably perform a breaking process excellent in end surface quality of a machined end face.

In order to solve the above problems, the method for processing a brittle material substrate according to the present invention is to set a predetermined line of a scribe line starting from a substrate end to a brittle material substrate, and to form a crack having a finite depth along a predetermined line of scribe lines, which is characterized in that: Positioning the line near the start end of the predetermined line and separating the line from the start end to the inner side of the substrate, crimping the cutter wheel to form an initial crack separated from the start end; secondly, by laser irradiation The beam spot formed on the substrate surface is relatively moved along the predetermined line of the scribe line from the start end through the initial crack, thereby performing local heating at a temperature lower than the softening temperature, and then cooling the locally heated region. In the vicinity, a crack having a finite depth starting from the position of the initial crack is formed along a predetermined line of the scribe line.

According to the present invention, when the initial crack is formed on the predetermined line of the scribe line, the initial crack formation position is not the substrate end of the brittle material substrate but is separated from the substrate end toward the substrate inner side direction, so that the initial crack and the substrate End separation. The initial crack is formed by crimping the cutter wheel in the direction of the line to be scribed, and the direction of the initial crack is directed toward the line of the predetermined line. Next, the beam spot is relatively moved along the predetermined line of the scribe line, whereby the substrate is locally heated by passing the initial crack from the beginning end of the predetermined line of the scribe line. Further, the vicinity of the rear side of the area after the local heating is cooled. At this time, since there is no initial crack at the substrate end, the crack does not travel from the substrate end. Next, the beam spot is advanced from the substrate end, and the initial crack is heated at a position where it is slightly separated (at this time, a compressive stress is generated at the initial crack surface and the crack does not travel), and then the blade is slightly advanced, and the turtle is cooled at the initial stage. At the time of the crack (at this time, a tensile stress is generated in the initial crack surface to generate a compressive stress in the initial crack), and a crack having a finite depth starting from the initial crack is formed.

At this time, even if the stress distribution in the front-rear direction (the predetermined line direction of the scribe line) is formed in the vicinity of the substrate end, and the force is pulled to the right and left (the force for inducing the full cutting line), since the initial crack is not formed at the substrate end, Therefore, a full cut line that travels from the substrate end is not formed. Then, once the crack of the line depth starting from the initial crack is formed, the stencil of the finite depth is continuously formed on the line of the scribe line as the beam spot scans, and the desired scribe line is formed. As described above, since a situation in which it is difficult to form a full cutting line is created, even if the heating condition or the cooling condition of the beam spot is not changed to a more extreme condition than before, it does not migrate to the full cutting line, and instead is replaced by Form a deeper line.

According to the present invention, it is difficult to form a full cutting line when performing laser scribing, and it is possible to expand the process tolerance of the scribe line which can form a crack having a finite depth (a range of heating conditions or cooling conditions which can be set) . As a result, the scribe line can be stably formed.

Moreover, according to the present invention, even if the processing conditions (heating conditions, cooling conditions) of the laser scribing are not changed to more extreme conditions than in the past, the full cutting line is not formed, and the scribing can be formed. As a result, it is possible to form a deeper scribe line than in the past. Furthermore, since the crack is not formed at the end of the substrate, the occurrence of the "first" phenomenon can be suppressed.

In the above invention, a grooved cutter wheel having a periodic groove formed in the cutting edge may be used as the cutter wheel.

Further, in the above invention, the separation distance from the start end of the predetermined line to the initial crack may be 2 mm to 7 mm.

Further, in order to solve the above-described problem of the other brittle material substrate, the second predetermined laser beam is irradiated along the predetermined line to the second substrate end of the brittle material substrate, and the second laser irradiation is performed to The substrate is processed.

(a) First, the first initial crack forming step is performed, and the first initial crack is formed on the inside of the substrate so as to be separated from the first substrate end by the predetermined line on the scribe line near the first substrate end. (b) secondly performing a laser scribing step such that the beam spot of the first laser irradiation is relatively moved from the first substrate end side to the second substrate end along the predetermined line of the scribe line, and the substrate is heated at a temperature lower than the softening temperature. And immediately after the passage of the beam spot, the refrigerant is blown to be cooled, whereby a gradation of a limited depth is formed along a predetermined line of the scribe line by a stress gradient generated in a depth direction of the predetermined line of the scribe line.

At this time, by appropriately selecting the heating conditions of the beam spot and the cooling conditions of the cooling point, it is possible to form a scribe line formed by a crack having a finite depth formed by the stress gradient in the depth direction without forming a full cutting line. Specifically, if the heating condition (for example, increasing the laser output) or the cooling condition (for example, increasing the amount of refrigerant injection) that causes the temperature difference on the surface of the substrate to be extreme is set too much, it is easier to form the entire line than the line. Since the tendency of the line is cut, the heating condition or the cooling condition is not set to an excessively extreme condition. However, since the initial crack is not formed at the first substrate end, the entire cutting line from the substrate end is less likely to occur, and the process tolerance that can be selected is increased. Therefore, the heating condition and the cooling can be made larger than the conventional temperature. Conditional laser scribing processing.

(c) Next, the second initial crack forming step is performed, and at least one of the predetermined line between the first substrate end or the first substrate end and the first initial crack is formed to form a second initial crack.

Thereby, the incision for inducing the traveling direction of the crack can be formed in the vicinity of the first substrate end in the next laser breaking step.

(d) Next, the laser cracking step is performed such that the beam spot of the second laser irradiation is relatively moved from the first substrate end to the second substrate end along the scribe line, so that the scribe line is further penetrated or completely broken.

Thereby, the crack can be propagated from the first substrate end to the second substrate end, and the crack can be surely formed, and the traveling direction of the crack formed in the vicinity of the first substrate end by the second initial crack can be induced. Prevent the formation of uncontrollable cracks such as the "first move" phenomenon.

According to the present invention, the scribe line formed by the laser scribing step can be formed into a deep scribe line, or the scission can be easily performed.

Further, in the laser scribing process, since the allowable process tolerance (the range that can be set as the processing conditions) can be expanded, it is possible to form a deep scribe line using the above-described extreme heating conditions and cooling conditions. Moreover, by forming a deeper scribe line, the process tolerance (which can be set as a processing condition) that can be set at the time of laser cracking processing can be expanded, and can be stabilized without moving to full cut. The scribe line is formed to be completely broken deep or stably.

In the second initial crack forming step of the above (c), the second initial cracking system is continuously formed from the first substrate end to the first initial crack along the predetermined line of the scribe line.

Thereby, the first phenomenon can be completely solved by causing the crack to travel from the first substrate end to the first initial crack along the predetermined line of the scribe line in the next laser rupture step.

Further, in the above invention, the first initial crack and the second initial crack may be formed by crimping the cutter wheel. Thereby, the initial crack of the fine cut can be reliably formed even on the surface of the substrate separated from the substrate end.

In particular, by using a cutter wheel having a periodic groove formed in the cutting edge, the blade edge becomes less likely to slide on the substrate surface, and when an initial crack is formed at a position separated from the substrate end, only a short distance can be rolled ( From about 1 mm to about 2 mm, it is sure to form a stable initial crack. As a grooved cutter wheel in which a cycle groove is formed in the cutting edge, a high-permeability tip "PENET" (registered trademark) or "APIO" (registered trademark) manufactured by Samsung Diamond Industrial Co., Ltd. can be used.

Further, in the above invention, the first initial crack may be formed by a crimping cutter wheel, and the second initial crack may be partially caused by the laser from the first initial crack toward the first substrate end side. Formed by irradiation.

Thereby, the first initial crack on the substrate can reliably form an initial crack of the fine cut by the cutter wheel. In the second initial crack, since the first initial crack is formed, it is possible to cause the crack to travel by the partial irradiation of the laser from the first initial crack toward the first substrate end side, thereby inducing the first 2 initial cracks.

Further, in the above invention, the second initial crack may be formed to be deeper than the first initial crack. Specifically, the pressure contact force of the cutter wheel when the second initial crack is formed, for example, may be stronger than when the first initial crack is formed.

Thereby, the depth of the crack can be simply deepened in the subsequent laser cracking step.

Hereinafter, embodiments of the present invention will be described based on the drawings.

First, an example of a substrate processing apparatus used in carrying out the processing method of the present invention will be described.

Fig. 1 is a schematic configuration diagram of a substrate processing apparatus LS1 capable of carrying out the processing method of the present invention. Here, the case where the glass substrate is processed will be described as an example, but the brittle material substrate such as the tantalum substrate is also the same.

First, the overall configuration of the substrate processing apparatus LS1 will be described. A slide table 2 that reciprocates in a rearward direction (hereinafter referred to as a Y direction) of the guide rails 3, 4 in the front and back of the paper of Fig. 1 is provided along one of the parallel arrangement on the horizontal gantry 1. The lead screw 5 is disposed between the two guide rails 3 and 4 in the front-rear direction, and the fixing member 6 fixed to the slide table 2 is screwed to the lead screw 5, and is driven by a motor (not shown). The guide screw 5 is rotated forward and backward to reciprocate the slide table 2 along the guide rails 3, 4 in the Y direction.

A water platform seat 7 that reciprocates along the guide rail 8 in the left-right direction (hereinafter referred to as the X direction) of FIG. 1 is disposed on the slide table 2. A lead screw 10 that is rotated by a motor 9 is screwed into a bracket 10a fixed to the pedestal 7, and the pedestal 7 is reciprocated along the guide rail 8 in the X direction by the forward and reverse rotation of the lead screw 10.

The turret 7 is provided with a rotary table 12 that is rotated by a rotating mechanism 11, and the glass substrate A is attached to the rotary table 12 in a horizontal state. The glass substrate A is, for example, a mother substrate for cutting out a small unit substrate. The rotating mechanism 11 rotates the turntable 12 about a vertical axis and is rotatable so as to be at an arbitrary rotation angle with respect to the reference position. Further, the glass substrate A is fixed to the turntable 12 by a suction chuck.

Above the turntable 12, the laser device 13 and the optical holder 14 are held on the mounting frame 15.

The laser device 13 may be a conventional laser device for processing a brittle material substrate, and specifically, an excimer laser, a YAG laser, a carbon dioxide laser, or a carbon monoxide laser may be used. In the processing of the glass substrate A, it is preferred to use a carbon dioxide laser which can oscillate light of a wavelength at which the energy absorption efficiency of the glass material is large.

The laser beam emitted from the laser device 13 has a beam spot of a predetermined shape and is irradiated onto the glass substrate A by an optical holder 14 in which a lens optical system for adjusting the shape of the beam is assembled. The shape of the beam spot is excellent in that the shape of the long axis (elliptical shape, oblong shape, or the like) can be efficiently heated along the predetermined line of the scribe line, as long as it can be at a temperature lower than the softening temperature. The shape of the heating is not particularly limited as long as the shape of the beam is heated. In the present embodiment, a beam spot having an elliptical shape is formed.

In the mounting frame 15, the proximity optical holder 14 is provided with a cooling nozzle 16. The refrigerant is ejected by the cooling nozzle 16. Cooling water, compressed air, helium gas, carbon dioxide, or the like can be used as the refrigerant, and in the present embodiment, compressed air is sprayed. The cooling medium ejected from the cooling nozzle 16 is directed to a position slightly separated from the left end of the beam spot, whereby a cooling point is formed on the surface of the glass substrate A.

Further, a cutter wheel 18 having a periodic groove portion is attached to the mounting frame 15 via the elevating mechanism 17. This cutter wheel 18 is used when the glass substrate A forms the initial crack Tr, and is temporarily lowered from above the glass substrate A.

Fig. 2 is a schematic view showing a cutter wheel having a periodic groove portion, Fig. 2(a) is a front view, and Fig. 2(b) is a side view. The cutter wheel 18 having the periodic groove portion is periodically formed with the groove portion 18b along the blade edge 18a (further, for convenience of explanation in Fig. 2, the size of the groove portion 18b of the blade edge 18a is more exaggerated than the actual one. Depict). Specifically, the groove pitch is set in the range of 20 μm to 200 μm in accordance with the cutter wheel diameter of 1 to 20 mm. Further, the groove depth is 2 μm to 2500 μm.

By using the cutter wheel of the special tool tip described above, it is possible to form not only a crack that penetrates deeper than the cutter wheel having no groove portion, but also the blade tip is not easy to slide on the substrate surface, so that when the initial crack is formed, only the shorter one can be rolled. The distance (1 mm to 2 mm) means that the initial crack is reliably formed on the substrate surface.

Further, a camera 20 capable of detecting an alignment mark for positioning on the glass substrate A is mounted on the substrate processing apparatus LS1, and can be set on the substrate from the position of the alignment mark detected by the camera 20. The position of the predetermined line on A is corresponding to the positional relationship of the rotary table 12, and is correctly positioned to the lowered position of the cutter wheel 18 or the irradiation position of the laser beam to reach the predetermined line of the line.

Next, the processing operation of the substrate processing apparatus LS1 will be described. 3 is a view showing a processing operation procedure of laser scribing processing until a finite depth of scribe line is formed by the first laser irradiation, and FIG. 4 is a view showing a laser cracking by the second laser irradiation. A diagram of the processing steps until the processing is interrupted. In addition, in FIG. 3 and FIG. 4, only the main part of FIG. 1 is shown.

First, as shown in FIG. 3(a), the glass substrate A is placed on the turntable 12 and fixed by a suction chuck. An alignment mark (not shown) imprinted on the glass substrate A is detected by the camera 20 (FIG. 1), and based on the detection result, the positional relationship between the predetermined line of the scribe line, the rotary table 12, the slide table 2, and the pedestal 7 is established. . Thereafter, the turntable 12 and the slide table 2 are actuated to adjust the position so that the direction of the cutting edge of the cutter wheel 18 coincides with the direction of the predetermined line of the scribe line.

Next, as shown in FIG. 3(b), the pedestal 7 (FIG. 1) is actuated to move the rotary table 12 so that the cutter wheel 18 comes into the glass substrate A to form the first substrate end A1 of the first initial crack. It is above the position separated from the first substrate end A1.

Next, as shown in Fig. 3(c), the elevating mechanism 17 is actuated to lower the cutter wheel 18. Next, the blade edge is pressed against the substrate A to form the first initial crack Tr1. At this time, the pedestal 7 is moved by about 2 mm, and the cutter wheel 18 is rolled on the substrate, whereby the stable first initial crack Tr1 is surely formed.

Next, as shown in FIG. 3(d), the elevating mechanism 17 and the rotary table 12 are returned to the original position (the position of FIG. 3(a)), and the laser device 13 is actuated to illuminate the laser beam. The refrigerant is injected from the cooling nozzle 16. The heating conditions and the cooling conditions such as the laser output or the amount of the refrigerant to be irradiated at this time are set within a range where the through crack (that is, the full cut) is not generated at the position of the first initial crack Tr1.

Since the first initial crack Tr1 is separated from the substrate end (the first substrate end A1) and formed at the inner side of the substrate, even if the first substrate end A1 is pulled to the right and left, the force is pulled (it becomes the fully cut state). The first substrate end A1 is still in a state in which cracks are hard to occur. Therefore, compared with the case where the initial crack is formed in the substrate end A1 in advance, it is difficult to achieve full cutting. Further, regarding the heating conditions and cooling conditions such as the laser output to be irradiated or the amount of refrigerant to be injected, it is possible to select an increase in the process tolerance which does not cause the full cutting. Therefore, as the set heating condition or cooling condition, it is also possible to select a condition that is more extreme than when the initial crack is formed on the substrate end, and a condition that a deeper scribe line can be formed.

Next, as shown in Fig. 3(e), the pedestal 7 is moved so that the beam spot of the laser beam formed on the substrate A and the cooling point of the refrigerant from the cooling nozzle 16 are scanned along a predetermined line.

By the above operation, the substrate A is formed with a scribe line composed of a crack of a limited depth starting from the position of the first initial crack Tr1. Then, in a range that does not become a through crack, an appropriate heating condition (that is, an extreme condition in a range that does not become a full cut) or a cooling condition of the refrigerant can be appropriately selected, thereby forming a deeper difficulty in forming in the past. Dash. Further, a region where the crack Cr is not formed is present on the substrate end (first substrate end A1) on the first initial crack Tr1 side of the substrate A.

Secondly, the laser cracking process will be explained.

As shown in Fig. 4 (a), the turntable 12 is returned to the original position (the position of Fig. 3 (a)), and the elevating mechanism 17 is actuated to lower the cutter wheel 18.

Next, as shown in FIG. 4(b), the substrate A and the cutter wheel 18 are moved closer to each other, and the cutter wheel 18 is brought into contact with the first substrate end A1 to form the second initial crack Tr2 at the substrate end. At this time, the turntable 12 can be continuously moved, and the second initial crack Tr2 can be continuously formed to the first initial crack Tr1.

Further, the second initial crack Tr2 may be formed deeper than the first initial crack Tr1 by changing the pressure contact force. At this time, the crack can be easily formed deep as will be described later.

Next, as shown in FIG. 4(c), the elevating mechanism 17 and the rotating table 12 (the pedestal 7) are returned to the original position (the position of FIG. 3(a)), and the laser device 13 is actuated to illuminate the laser beam. The heating conditions such as the laser output at this time are left to be described later.

Next, as shown in FIG. 4(d), the substrate A is moved to scan the beam spot formed on the substrate A along the scribe line from the first substrate end A1 toward the second substrate end A2. By this, the deep crack CR2 travels along the crack Cr (scribe line) with the second initial crack Tr2 (that is, the first substrate end A1) as a starting point, so that the deeper scribe line can be formed to the second substrate. End A2.

Here, the heating conditions at the time of the laser splitting treatment will be described. The heating conditions such as the laser output may be the same as in the case of the first laser irradiation, but it is preferably set as follows.

In the laser cracking process, the scanning speed is set to be faster than that of the first laser irradiation, and the heating time at each point on the scribe line is shortened (the laser output is set to be higher), and the surface of the scribe line is Only heat for a short time. The reason for this is that a stress gradient for deeply penetrating the crack Cr can be formed between the surface layer of the substrate and the inside of the substrate.

Figure 5 is a cross-sectional view showing, in a schematic manner, the stress gradient that will be formed during the laser splitting process. The surface layer of the substrate is heated for a short time to form a heating region H. Next, a large compressive stress HR is formed on the surface layer of the substrate, and the opposite tensile stress CR is generated inside the substrate. When there is a crack Cr inside the substrate, the tensile stress concentrates on the front end of the crack Cr, and as a result, the crack Cr can penetrate deeper.

If the heating time of the surface layer of the substrate is gradually increased, heat is transferred to the inside of the substrate to make the temperature difference generated in the depth direction small. As a result, the stress gradient in the depth direction is weakened. Therefore, in the laser cracking treatment, in order to set the heating stress and the cooling conditions for forming the compressive stress on the surface layer of the substrate and forming the tensile stress inside the substrate, it is preferable to strongly heat the substrate in a short time without being softened. Heating conditions. Further, by cooling the refrigerant before the heating, the temperature difference in the depth direction can be increased, and the tensile stress can be easily generated inside the substrate.

Further, the reason why the second initial crack is formed to be the first initial crack can be easily formed by forming a deeper scribe line.

The second initial crack Tr2 formed deep in the vicinity of the first substrate end A1 is used as the start end of the laser cracking process, and the initial position of the crack front end at which the tensile stress is concentrated can be set as the deep position of the substrate. . Laser irradiation is performed in this state, whereby a strong compressive stress on the surface layer of the substrate can be imparted. Thereby, the tensile stress concentrates on the front end of the crack at a deeper position, and the distance from the surface of the substrate to the front end of the crack is longer to a certain extent, that is, the larger the force (torque) that is to be spread out is applied to the front end of the fracture. The direction so that the crack can be easily infiltrated.

As described above, in the laser cracking process, the second laser irradiation is irradiated from the second initial crack formed on the first substrate end toward the second substrate end, whereby the deeper crack Cr2 can be formed. The scribe line is formed, and when the crack Cr2 is as deep as the back surface, the substrate can be completely broken by the laser rupture treatment.

The fracture surface formed by this method is very beautiful and excellent in straightness, and is ideal as a machined end face.

Next, a processing method according to a second embodiment of the present invention will be described. Here, the second initial crack Tr2 is formed by laser irradiation. Fig. 6 is a view showing a processing operation procedure of a laser cutting step in the processing method of the second embodiment. In addition, since it is the same as FIG. 3 until the laser scribing step, description is abbreviate|omitted.

By the laser scribing process similar to the step up to FIG. 3(e), the substrate A is formed with a scribe line composed of a crack of a limited depth starting from the position of the first initial crack Tr1. In this state, it moves to the laser splitting process.

As shown in FIG. 6(a), the turntable 12 is slightly returned so that the first initial crack Tr1 comes under the optical holder 14.

Next, as shown in FIG. 6(b), the laser device 13 is actuated to illuminate the laser beam to heat the first initial crack Tr1, and the rotating table 12 (the pedestal 7) is moved to make the beam point to the first substrate. The end A1 moves. As a result, the crack progresses from the first initial crack Tr1 toward the first substrate end A1, and the second initial crack Tr2 is continuously formed from the first substrate end A1 to the first initial crack.

Next, as shown in Fig. 6(c), the turntable 12 (the pedestal 7) is returned to the original position (the position of Fig. 3 (a)), and the laser device 13 is actuated to illuminate the laser beam.

Next, as shown in FIG. 6(d), the substrate A is moved to scan the beam spot formed on the substrate A along the scribe line from the first substrate end A1 toward the second substrate end A2. Thereby, since the deep crack CR2 travels along the crack Cr (scribe line) starting from the second initial crack Tr2 (that is, the first substrate end A1), the deeper scribe line can be formed to the second substrate end. A2.

Further, in the above two embodiments, the second initial crack is continuously formed to the first initial crack, but the initial crack is close to a certain extent, and the laser cracking treatment is performed even in the case where the crack is not continuous. The result is still able to form a continuous line. In addition, even if the second initial crack Tr2 is formed only on the first substrate end, a continuous scribe line can be formed as long as the distance to the first initial crack is sufficiently close.

The present invention can be used for processing in which a deep scribe line is formed on a brittle material substrate such as a glass substrate, or in a process of completely breaking it.

2. . . Sliding table

7. . . Pedestal

12. . . Rotary table

13. . . Laser device

16. . . Cooling nozzle

17. . . Lifting mechanism

18. . . Cutter wheel with periodic groove

A. . . Glass substrate (brittle material substrate)

BS. . . Beam point

CS. . . Cooling point

Cr. . . crack

Cr1. . . Deep crack

Cr2. . . crack

Tr. . . Initial crack

Fig. 1 is a schematic configuration diagram of a substrate processing apparatus used in carrying out the substrate processing method of the present invention.

2(a) and 2(b) are views showing the configuration of a cutter wheel having a periodic groove portion.

3(a) to 3(e) are views showing a part of the operation steps of the processing method according to the embodiment of the present invention.

4(a) to 4(d) are views showing a part of the operation steps of the processing method according to the embodiment of the present invention.

Figure 5 is a cross-sectional view schematically showing a stress gradient to be formed at the time of laser cracking.

6(a) to 6(d) are views showing a part of the operation steps of the processing method according to another embodiment of the present invention.

7(a) to (c) are cross-sectional views showing the manner in which a finite depth is formed in a schematic manner.

8(a) and 8(b) are a perspective view and a plan view showing a substrate in which a full cutting line is formed in a schematic manner.

Figure 9 is a diagram showing the leading phenomenon occurring at the substrate end.

12. . . Rotary table

13. . . Laser device

16. . . Cooling nozzle

17. . . Lifting mechanism

18. . . Cutter wheel with periodic groove

A. . . Glass substrate (brittle material substrate)

A1. . . First substrate end

A2. . . Second substrate end

Cr. . . crack

Cr1. . . Deep crack

Cr2. . . crack

Tr. . . Initial crack

Tr1. . . First initial crack

Tr2. . . 2nd initial crack

Claims (5)

A method for processing a brittle material substrate, wherein the substrate is processed along a predetermined line of a scribe line set on a first substrate end to a second substrate end of the brittle material substrate to process the substrate, wherein: (a) The first initial crack forming step is to form a first initial crack so as to be separated from the first substrate end by a line on a scribe line near the first substrate end; (b) a laser scribing step The beam spot of the first laser irradiation is relatively moved from the first substrate end side along the predetermined line of the scribe line to the second substrate end, and the substrate is heated at a temperature lower than the softening temperature, and the portion after the beam spot passes Immediately blowing the refrigerant to cool it, thereby forming a scribe line having a finite depth along the predetermined line of the scribe line; (c) the second initial crack forming step, and cracking at the first substrate end or the first substrate end and the first initial stage At least one of the predetermined line between the lines forms a second initial crack; (d) a laser cracking step, and the beam spot of the second laser irradiation is relatively moved from the first substrate end along the scribe line to the scribe line The second substrate end causes the scribe line to further penetrate or completely break. The method for processing a brittle material substrate according to the first aspect of the invention, wherein, in the second initial crack forming step of (c), the second initial cracking system is continuously formed from the first substrate end along the predetermined line of the scribe line. Crack to the first early stage. The method for processing a brittle material substrate according to claim 1, wherein the first initial crack and the second initial crack are by a crimping cutter wheel And formed. The method for processing a brittle material substrate according to the first aspect of the invention, wherein the first initial cracking system is formed by a crimping cutter wheel, and the second initial cracking system is oriented from the first initial crack to the first The laser on the end side of the substrate is partially irradiated to form. The method for processing a brittle material substrate according to the first aspect of the invention, wherein the second initial crack is formed to be deeper than the first initial crack.