TWI587960B - Laser processing method and laser processing device - Google Patents

Description

Laser processing method and laser processing device

The present invention relates to a laser processing method and a laser processing apparatus, and more particularly to a method of irradiating laser light along first and second planned lines intersecting the surface of a brittle material substrate, and forming a plurality of grooves on the surface of the brittle material substrate. Laser processing method and laser processing apparatus for carrying out the method.

The rectangular glass used as the material of the electronic component is obtained by dividing a substrate (glass plate) which is a large base material in the direction orthogonal to each other. As a breaking method, there is a method in which a groove is formed by rolling a cutter wheel or the like to form a groove, and an external force is applied to the substrate from a groove formed in a vertical direction to separate the substrate.

Further, Patent Document 1 proposes a method of irradiating a surface of a substrate with laser light along a line to be orthogonal to each other, forming a groove along each planned line, and then applying an external force to the substrate to perform division.

Further, Patent Document 2 discloses another laser processing method. In this method, the surface of the substrate is ablated by irradiating the pulsed laser light along the planned line, and at the same time, the surface of the groove formed by the ablation process is melted, thereby reducing the occurrence of ablation processing. The micro crack. With this method, a groove is formed in the substrate.

[Advanced technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2012-31035

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2010-274328

In the method disclosed in Patent Document 1, it is necessary to provide a reflecting member at each of the four corner portions of the portion where the two processing lines intersect, which causes the processing steps to become complicated.

Further, two orthogonal grooves (hereinafter referred to as "cross scribe") can be formed by the method described in Patent Document 2. However, in this case, when the groove in the first direction is formed after the groove in the first direction is formed, it is easy to cause a machining failure in the vicinity of the groove intersection portion.

Specifically, when the groove in the second direction is formed, there is a thermal influence due to the irradiation of the laser light, and a crack occurs in the groove in the first direction or is fixed to the intersection portion substrate (glass). A situation in which the break is bad. Further, debris (concavity and convexity) is likely to occur at the corner portion of the cross section of the groove in the second direction.

Therefore, for example, it is necessary to set the output of the laser light when the groove in the second direction as the subsequent step is formed to be lower than the case where the groove in the first direction is formed. However, depending on the type of the substrate, if the output of the laser light is reduced to such an extent that no defect or breakage is caused, the problem cannot be broken. Therefore, the condition setting of the laser light at the time of cross scribing is very difficult.

An object of the present invention is to enable a substrate to be reliably separated by a simple step without causing a breakage.

The laser processing method according to the first aspect of the present invention is a method of irradiating laser light along the first and second planned lines intersecting the surface of the brittle material substrate, and forming a plurality of grooves on the surface of the brittle material substrate, and including 1 step and 2 steps. The first step is to process along the first The predetermined line irradiates the pulsed laser light to form a groove in the first direction on the brittle material substrate. In the second step, the pulsed laser light is irradiated along the second planned line, and the irradiation of the pulsed laser light is stopped in a portion intersecting the groove in the first direction, and the groove in the second direction is formed on the brittle material substrate.

Here, when the groove in the second direction is formed, the irradiation of the pulsed laser light is stopped in a portion intersecting the groove in the first direction formed first. Therefore, defects such as cracks or chips due to heat influence are less likely to occur in and around the intersection. Further, the grooves in the first and second directions can be processed under the same irradiation conditions of the laser light, and the processing can be facilitated. Moreover, a groove of a suitable depth can be formed, and the substrate can be easily separated in a subsequent step.

In the laser processing method according to the first aspect of the invention, in the method of the first aspect, in the second step, the irradiation of the pulsed laser light is stopped and the irradiation is restarted in the groove width of the first direction.

Here, when the groove in the second direction is formed, if the irradiation of the pulsed laser light is stopped and the irradiation is restarted in the unprocessed portion where the groove of the first direction is not formed, the position of the irradiation of the pulsed laser light is stopped. Cracks are likely to occur near the restarting position, resulting in a high defect rate of the product.

Therefore, in the method of the second aspect, the irradiation of the pulsed laser light is stopped and restarted in the groove width of the first direction which has been formed. Thereby, it is possible to suppress defects such as cracks in the product portion.

A laser processing method according to a third aspect of the invention is the method of the second aspect, wherein in the second step, the width of the groove in the first direction is 62% or more across the center of the groove in the first direction The irradiation of the laser light is stopped within a range of 94% or less.

Here, defects near the intersection of the grooves in both directions can be further suppressed.

The laser processing method according to any one of the first to third aspects of the present invention, wherein the brittle material substrate is ablated by pulsed laser light in the first step and the second step At the same time, the processed portion is melted to form grooves in the first and second directions.

Here, the substrate is ablated by pulsed laser light, and the processed portion is melted to form grooves in the first and second directions on the surface of the substrate. In this processing method, since the vicinity of the trench is heated, defects due to heat are easily generated.

Therefore, in such a processing method, defects caused by heat influence can be effectively suppressed by employing the method of the present invention.

A laser processing apparatus according to a fifth aspect of the present invention is characterized in that a laser beam is irradiated along the first and second planned lines intersecting the surface of the brittle material substrate, and a plurality of grooves are formed on the surface of the brittle material substrate. The processing apparatus includes a laser beam irradiation mechanism, a moving mechanism, and a processing control unit. The laser light irradiation mechanism has a laser oscillator that oscillates the pulsed laser light, and an optical system that condenses and oscillates the oscillated pulsed laser light. The moving mechanism relatively moves the laser light irradiation mechanism along a planned line of the surface of the brittle material substrate. The processing control unit controls the laser light irradiation mechanism and the moving mechanism to form a groove that intersects the brittle material substrate. Furthermore, the machining control unit has a first function and a second function. The first function irradiates the pulsed laser light along the first planned line to form a groove in the first direction on the brittle material substrate. The second function irradiates the pulsed laser light along the second planned line and stops the irradiation of the pulsed laser light at a portion intersecting the groove in the first direction to form a groove in the second direction of the brittle material substrate.

As described above, in the present invention, it is possible to surely separate the substrate without a break failure by a simple procedure.

1‧‧‧Laser oscillator

2‧‧‧Mirror mechanism

3‧‧‧Lens mechanism

4‧‧‧XY platform

5‧‧‧Substrate

10‧‧‧Control Department

11‧‧‧Road Control Department

12‧‧‧Mobile Control Department

Fig. 1 is a schematic block diagram of a laser processing apparatus for carrying out the processing method of the present invention.

Fig. 2 is a view schematically showing ablation processing in an embodiment of the present invention.

Fig. 3 is a view showing a timing chart of control of pulsed laser light.

Fig. 4 is a photograph showing the surface of the substrate and the cross-section when the cross-scouring is performed by the conventional laser processing method.

Fig. 5 is a photograph showing the surface of the substrate when cross-scouring is performed by the laser processing method according to the prior art and the embodiment of the present invention.

Fig. 6 is a photograph showing a cross section of a case where cross-scouring is performed by a laser processing method according to an embodiment of the present invention.

Fig. 7 is a photograph showing the surface of the substrate and the cross-section when the cross-scouring is performed under optimum conditions.

Fig. 8 is a view showing an example of control of pulsed laser light.

[Laser processing device]

A laser processing apparatus according to an embodiment of the present invention is shown in Fig. 1. The laser processing apparatus includes a laser oscillator 1, a mirror mechanism 2, a lens mechanism 3, and an XY stage 4. The laser oscillator 1, the mirror mechanism 2, and the lens mechanism 3 constitute a laser light irradiation means, and further, a moving mechanism is constituted by an XY stage. Further, the laser processing apparatus includes a control unit 10 including a laser control unit 11 and a movement control unit 12. The laser control unit 11 controls processing conditions such as irradiation and output of laser light. The movement control unit 12 controls the movement of the XY stage 4.

The laser oscillator 1 oscillates the pulsed laser light. The laser oscillator 1 is not particularly limited as long as it is a well-known pulsed laser oscillator such as a YAG laser or an IR laser. The laser of the wavelength at which the ablation process can be performed can be appropriately selected according to the material of the processed brittle material substrate (hereinafter simply referred to as "substrate") 5.

The mirror mechanism 2 and the lens mechanism 3 together form a collecting optical mechanism for changing the traveling direction of the pulsed laser light by irradiating the substrate 5 with pulsed laser light in a substantially vertical direction. As the mirror mechanism 2, one or more mirror surfaces can be used, and a 稜鏡, diffraction grating can also be used. Wait.

The lens mechanism 3 condenses the pulsed laser light. More specifically, the lens mechanism 3 adjusts the position at which the focus position of the pulsed laser light is concentrated, that is, the position in the up-down direction, based on the thickness of the substrate 5. The adjustment of the focus position can be adjusted by exchanging the lens of the lens mechanism 3, or can be adjusted by changing the position of the lens mechanism 3 in the up-and-down direction by an actuator (not shown).

The XY stage 4 mounts a stage on which the substrate 5 to be processed, such as a glass substrate to be cut, is placed, and is movable in the X direction and the Y direction orthogonal to each other. The movement control unit 12 controls the XY stage 4 to move in the speed X direction and the Y direction in a predetermined manner, thereby freely changing the relative position of the substrate 5 placed on the XY stage 4 and the pulsed laser light. Typically, the XY stage 4 is moved to move the pulsed laser light along a planned line of scribed grooves 6 formed on the surface of the substrate 5. Further, the moving speed of the XY stage 4 at the time of processing is controlled by the movement control unit 12.

[About ablation processing]

Fig. 2 shows an example of ablation processing by pulsed laser light. As shown in the figure, the pulsed laser light emitted from the laser oscillator 1 is collected by the lens mechanism 3 near the upper surface of the substrate 5. When the pulsed laser light is absorbed, as shown in Fig. 2(a), the vicinity of the focal position of the substrate 5 is heated.

When the temperature near the focal position of the substrate 5 exceeds the boiling point of the substrate 5, as shown in Fig. 2(b), a part of the component exceeding the boiling point evaporates. On the other hand, in the portion slightly away from the focus position, there is a portion which does not reach the boiling point of the substrate 5 but exceeds the melting point. When the portion is melted as shown in Fig. 2(c) and the temperature is lowered by the heat dissipation thereafter, as shown in Fig. 2(d), a melt mark is formed by fixation.

When the scribed groove is formed by the above processing method, if the ablation process is performed using pulsed laser light under the condition that the groove is not formed by the etched groove, that is, under the condition of suppressing the heat influence, it is easy to engrave Grooving creates defects. Furthermore, when it becomes too molten, Cracks will be generated by scratching the grooves. Therefore, it is necessary to perform processing by setting appropriate conditions such as the output of the pulsed laser light or the scanning speed.

[Laser processing method]

In the case where the substrate 5 is formed with scribed grooves in the X direction and the Y direction orthogonal to each other, first, the pulsed laser light is condensed and irradiated onto the surface of the substrate 5. Then, the pulsed laser light is scanned along a planned line in the X direction (this step is referred to as "1st scribe" hereinafter). Thereby, the planned line along the X direction forms a scribed groove. Next, under the same conditions as the processing in the X direction, the pulsed laser light is scanned in a predetermined line in the Y direction (hereinafter, this step is referred to as "2nd scribe"). At this time, the irradiation of the pulsed laser light is stopped for a predetermined period of time in the groove width in which the groove in the X direction is formed. As shown in the timing chart of Fig. 3, the temporary irradiation of the pulsed laser light is stopped at the intersection of the grooves in each of the two directions. In Fig. 3, (a) is the waveform of the driving signal for the pulsed laser light, "H" is the breaking of the pulsed laser light (the irradiation is stopped), and "L" is the switching (the irradiation) of the pulsed laser light. Furthermore, (b) shows that the laser output at each intersection is "0" for a predetermined period.

Further, in the case of performing the groove processing in the X direction and the Y direction, the substrate 5 is ablated using pulsed laser light, and a heat influence is applied to the substrate 5 to melt the processed portion to form a groove.

[Experimental example] -Experiment 1

Fig. 4 shows the surface of the substrate and the cross-section when the cross-scratching is performed without the control of the pulsed laser light (irradiation stop and restart). The pulsed laser light has a wavelength of 266 nm, an average output of 7 W, and a substrate thickness of 0.3 mm OA-10 (manufactured by Nippon Electric Glass Co., Ltd.). Further, processing was performed from the 2nd side in the drawing, the processing width was 34 μm, and the processing depth was 44 μm.

Figure 4 (a) shows the surface of the substrate before the break, and (b) shows the substrate after the break. On the surface, (c) shows a section of the 1st scored side, and (d) shows a section of the 2nd scored side.

According to the experiment 1, when the control of the pulsed laser light was not performed, the following results were obtained.

. The groove on the 1st side (scratched) produces cracks.

. There is a case where the substrate (glass) is fixed at the intersection portion to cause a breakage failure.

. Debris is generated at the corner of the section of the 2nd scored side.

- Experiment 2

Fig. 5 shows a state in which the control of the temporary irradiation stop of the pulsed laser light (hereinafter referred to simply as "control") and the processing state of the substrate surface under the control (b). Here, the processing is performed from the 1st scribing side, and the pulsed laser light is controlled at the intersection portion at the 2nd scribing. The conditions, substrate, processing width and depth of the pulsed laser light were the same as in Experiment 1.

Further, in each of the drawings, the "command value" refers to the distance of the irradiation of the stop pulse laser light instructed by the control unit 10. The actual irradiation stop distance corresponding to the command value is such that the irradiation stop position and the irradiation start position are shortened by 1/2 of the pulse condensing diameter, and as a result, the shorter the command value is, the distance corresponding to the condensing path of the approximate pulse.

As can be seen from Fig. 5(b), no cracking occurred in the 1st scribing by the control of the pulsed laser light. Further, when the irradiation of the pulsed laser light is stopped and restarted in the unprocessed region where the groove is not formed in the 1st scratch by the command value of 50 μm or more, the processing line is interrupted, and the chip is generated on the 2nd scribing side. .

As described above, when the processing width of the groove is 34 μm, the command value needs to be 40 μm (the actual distance is 32 μm (actual measurement)) or less.

Further, Fig. 6 shows the processing state of the cross-section under the case where the control of the pulsed laser light is not performed in the experiment 2 (a) and the case (b) in which the control is performed. Here, the cross section of the 2nd scribing side is comparatively shown.

According to Fig. 6(b), when the pulse laser light is controlled, when the command value is 20 μm or less, the chip is generated at the corner portion of the 2nd scribe side section.

As described above, when the processing width of the groove is 34 μm, it is necessary to set the command value to 30 μm (the actual distance is 21 μm (actual measurement)) or more.

- Experiment 3

Fig. 7 shows a case where processing is performed by performing control of pulsed laser light under optimum conditions.

The wavelength of the pulsed laser light is 266 nm, the average output is 7 W, and the control command value (irradiation stop distance) of the pulsed laser light is 40 μm (the actual distance is 32 μm). OA-10 (manufactured by Nippon Electric Glass Co., Ltd.) having a substrate thickness of 0.3 mm. Further, processing was performed from the 1st side in the drawing, the processing width was 34 μm, and the processing depth was 44 μm.

Fig. 7(a) shows the surface of the substrate before the break, (b) shows the surface of the substrate after the division, (c) shows the cross section of the 1st scribed side, and (d) shows the cross section of the 2nd scribed side.

As is apparent from the above figures, defects due to adhesion or thermal influence of the substrate (glass) were not observed.

[to sum up]

Summarizing the above experimental results, the following situation can be known.

(1) Cracks may occur when a portion other than the scribed groove (unprocessed portion) stops or restarts the irradiation of the pulsed laser light.

(2) If the command value is 50 μm (actual distance is 45 μm) or more, chips are generated on the surface of the substrate. Further, when the command value is 20 μm (actual distance is 9 μm) or less, debris is generated at the corner portion of the sectional section. Therefore, when the processing width (groove width) of the 1st scribe is 34 μm, it is necessary to set the command value of the pulse break of the 2nd scribe side intersection point to 30 μm or more and 40 μm or less (the actual distance is 21 μm or more and 32 μm or less). ).

The above generalization, preferably as shown schematically in Fig. 8, stops the 2nd side The region irradiated by the pulsed laser light is 62% or more and 94% or less of the processing width (groove width) on the 1st side in the groove width of the scribed groove on the 1st side.

[Other Embodiments]

The present invention is not limited to the above embodiments, and various modifications and changes can be made without departing from the scope of the invention.

The substrate to be used is not limited to the substrate shown in the experimental example, and the present invention can be applied to various glass substrates or other brittle material substrates.

Claims (4)

A laser processing method for irradiating laser light along a first planned line to be processed and a second planned line of intersection along a surface of a brittle material substrate, and forming a plurality of grooves on a surface of the brittle material substrate, comprising: a first step The pulsed laser light is irradiated along the first planned line to form a groove in the first direction on the brittle material substrate; and the second step is to irradiate the pulsed laser light along the second planned line, and the first The portion of the groove intersecting in the direction stops the irradiation of the pulsed laser light, and the groove of the second direction is formed on the brittle material substrate. In the second step, the first step is the center of the groove in the first direction. The irradiation of the laser light is stopped within a range of 62% or more and 94% or less of the groove width in the direction. The laser processing method according to claim 1, wherein in the second step, the irradiation of the pulsed laser light is stopped and the irradiation is restarted in the groove width of the first direction. The laser processing method according to claim 1 or 2, wherein in the first step and the second step, the brittle material substrate is ablated by pulsed laser light, and the processed portion is melted to form the a groove in the first direction and the second direction. A laser processing apparatus that irradiates laser light along a first planned line to be processed and a second planned line of intersection along a surface of a brittle material substrate, and forms a plurality of grooves on a surface of the brittle material substrate, and includes a laser beam irradiation mechanism. The utility model has a laser oscillator for oscillating pulsed laser light and an optical system for concentrating the oscillated pulsed laser light, and a moving mechanism for processing the laser light irradiation mechanism along the surface of the brittle material substrate. a relative movement of the line; and a control unit that controls the laser light irradiation mechanism and the moving mechanism to form a groove intersecting the brittle material substrate; The control unit has a first function of irradiating the pulsed laser light along the first planned line to form a groove in the first direction on the brittle material substrate, and a second function of illuminating along the second planned line Pulse laser light, and stopping the irradiation of the pulsed laser light at a portion intersecting the groove in the first direction to form a trench in the second direction of the brittle material substrate, and interposing the center of the trench in the first direction Irradiation of the laser light is stopped in a range of 62% or more and 94% or less of the groove width in the first direction.