JP6035127B2 - Laser processing method and laser processing apparatus - Google Patents

Description

  The present invention relates to a laser processing method and a laser processing apparatus, and in particular, a laser that irradiates a laser beam along first and second scheduled processing lines intersecting a brittle material substrate surface to form a plurality of grooves on the brittle material substrate surface. The present invention relates to a processing method and a laser processing apparatus for carrying out the processing method.

  Rectangular glass used as an electronic component material is obtained by dividing a single large substrate (glass plate) as a base material in directions orthogonal to each other. As a dividing method, a method is widely used in which a cutter wheel or the like is pressed and rolled to form a groove, and then an external force is applied from the vertical direction to the substrate along the formed groove to divide the substrate.

  Patent Document 1 also proposes a method of irradiating a substrate surface with laser light along processing lines orthogonal to each other, forming grooves along each processing line, and then applying an external force to the substrate to divide the substrate. Has been.

  Further, Patent Document 2 discloses another laser processing method. In this method, the substrate surface is ablated by irradiating a pulsed laser beam along the planned processing line, and at the same time, the surface of the groove formed by ablation is melted to reduce microcracks caused by the ablation. ing. By such a method, a groove is formed in the substrate.

JP 2012-31035 A JP 2010-274328 A

  In the method disclosed in Patent Document 1, it is necessary to provide a reflecting member at each of the four corners where the two scheduled processing lines intersect, which complicates the processing process.

  It is also possible to form two orthogonal grooves (hereinafter referred to as “cross scribe”) using the method disclosed in Patent Document 2. However, in this case, when forming the groove in the second direction after forming the groove in the first direction, processing defects are likely to occur in the vicinity of the portion where the grooves intersect.

  Specifically, when forming the groove in the second direction, cracks occur in the groove in the first direction due to the thermal effect of laser light irradiation, or the substrate (glass) adheres at the intersection, resulting in poor separation. May occur. In addition, sores (unevenness) are likely to occur at the corners of the sectional surface of the groove in the second direction.

  For this reason, for example, it is necessary to perform control such that the output of the laser beam when forming the groove in the second direction, which is a subsequent process, is set lower than that when forming the groove in the first direction. However, depending on the type of the substrate, there is a problem that, when the output of the laser beam is reduced to such an extent that no defect or division failure occurs, division is impossible. For this reason, it is very difficult to set the laser beam conditions when cross-scribing.

  An object of the present invention is to enable a substrate to be reliably cut by a simple process without causing a cutting failure.

  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 scheduled processing lines intersecting the brittle material substrate surface to form a plurality of grooves on the brittle material substrate surface. It includes a first step and a second step. In the first step, a groove in the first direction is formed in the brittle material substrate by irradiating a pulse laser beam along the first processing scheduled line. In the second step, the pulse laser beam is irradiated along the second processing scheduled line, and the irradiation of the pulse laser beam is stopped at a portion intersecting the first direction groove, so that the second direction groove is formed in the brittle material substrate. Form.

  Here, when the groove in the second direction is formed, the irradiation of the pulsed laser beam is stopped at a portion intersecting with the groove formed in the first direction. For this reason, it becomes difficult to produce defects, such as a crack by a thermal influence, and a soge, in the crossing part and its vicinity. Further, the grooves in the first and second directions can be processed under the same laser light irradiation conditions, which facilitates the processing. In addition, a groove having an appropriate depth can be formed, and the substrate can be easily divided in a subsequent process.

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

  Here, when forming the groove in the second direction and stopping the irradiation of the pulse laser beam and restarting the irradiation in the unprocessed portion where the groove in the first direction is not formed, the position where the irradiation of the pulse laser beam is stopped In addition, cracks are likely to occur in the vicinity of the restarted position, resulting in a high product defect rate.

  Therefore, in the method according to the second aspect, the irradiation of the pulse laser beam is stopped and restarted within the already formed groove width in the first direction. Thereby, it can suppress that defects, such as a crack, arise in a product part.

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

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

  The laser processing method according to the fourth aspect of the present invention is the method according to any one of the first to third aspects, wherein in the first step and the second step, the brittle material substrate is ablated by the pulse laser beam and simultaneously the processed portion is formed. Melting to form grooves in the first and second directions.

  Here, the substrate is ablated by pulsed laser light, and at the same time, the processed portion is melted to form grooves in the first and second directions on the substrate surface. In such a processing method, since the vicinity of the groove is heated, defects due to thermal effects are likely to occur.

  Therefore, by adopting the method of the present invention in such a processing method, defects due to thermal influence can be effectively suppressed.

  A laser processing apparatus according to a sixth aspect of the present invention is an apparatus that irradiates laser light along first and second scheduled processing lines intersecting a brittle material substrate surface to form a plurality of grooves on the brittle material substrate surface. is there. This processing apparatus includes a laser light irradiation mechanism, a moving mechanism, and a processing control unit. The laser light irradiation mechanism has a laser oscillator that oscillates pulsed laser light and an optical system that focuses and irradiates the oscillated pulsed laser light. The moving mechanism relatively moves the laser beam irradiation mechanism along a planned processing line on the surface of the brittle material substrate. The processing control unit controls the laser beam irradiation mechanism and the moving mechanism to form a groove that intersects the brittle material substrate. Further, the machining control unit has a first function and a second function. The first function is to irradiate a pulsed laser beam along the first planned processing line to form a groove in the first direction in the brittle material substrate. The second function is to irradiate the pulse laser beam along the second processing planned line and stop the irradiation of the pulse laser beam at the portion intersecting with the groove in the first direction, so that the groove in the second direction of the brittle material substrate. Form.

  As described above, according to the present invention, the substrate can be surely divided by a simple process without causing a division failure.

The schematic block diagram of the laser processing apparatus for enforcing the processing method of this invention. The figure which shows typically the ablation process by one Embodiment of this invention. The figure which shows the timing chart example of control of a pulse laser beam. The photograph which shows the board | substrate surface at the time of carrying out the cross scribe by the conventional laser processing method, and a cross section. The photograph which shows the board | substrate surface at the time of cross-scribing with the laser processing method by the past and one Embodiment of this invention. The photograph which shows the cross section at the time of cross-scribing with the laser processing method by the past and one Embodiment of this invention. A photograph showing a substrate surface and a cross-section when cross-scribing under optimum conditions. The schematic diagram which shows the example of control of a pulsed laser beam.

[Laser processing equipment]
A laser processing apparatus according to an embodiment of the present invention is shown in FIG. This 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 beam irradiation mechanism, and the XY stage constitutes a moving mechanism. The laser processing apparatus has 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 laser light irradiation and output. The movement control unit 12 controls the movement of the XY stage 4.

  The laser oscillator 1 oscillates pulsed laser light. The laser oscillator 1 is not particularly limited as long as it is a known pulse laser oscillator such as a YAG laser or an IR laser. What is necessary is just to select suitably the laser of the wavelength which can be ablated according to the material of the brittle material board | substrate (henceforth a "board | substrate") 5 processed.

  The mirror mechanism 2 forms a condensing optical mechanism together with the lens mechanism 3, and changes the traveling direction of the pulse laser light so that the substrate 5 can be irradiated with the pulse laser light from a substantially vertical direction. As the mirror mechanism 2, one or a plurality of mirror surfaces may be used, or a prism, a diffraction grating, or the like may be used.

  The lens mechanism 3 collects pulsed laser light. More specifically, the lens mechanism 3 adjusts the vertical position of the focal position, which is the position where the pulse laser beam is condensed, according to the thickness of the substrate 5. The focal position may be adjusted by exchanging the lens of the lens mechanism 3 or may be adjusted by changing the vertical position of the lens mechanism 3 with an actuator (not shown).

  The XY stage 4 is a table on which a substrate 5 to be processed such as a glass substrate to be divided is placed, and is movable in the X direction and the Y direction orthogonal to each other. The relative position between the substrate 5 placed on the XY stage 4 and the pulse laser beam can be freely changed by controlling the XY stage 4 by the movement control unit 12 and moving it at a predetermined speed in the X and Y directions. can do. Usually, the XY stage 4 is moved, and the pulse laser beam is moved along the processing line of the scribe groove 6 formed on the surface of the substrate 5. Further, the movement speed of the XY stage 4 during processing is controlled by the movement control unit 12.

[About ablation processing]
FIG. 2 shows an example of ablation processing using pulsed laser light. As shown in this figure, the pulsed laser light emitted from the laser oscillator 1 is condensed near the upper surface of the substrate 5 by the lens mechanism 3. When the pulsed laser beam is absorbed, the vicinity of the focal position of the substrate 5 is heated as shown in FIG.

  When the temperature in the vicinity of the focal position of the substrate 5 exceeds the boiling point of the substrate 5, as shown in FIG. On the other hand, in a portion slightly away from the focal position, there is a portion that does not reach the boiling point of the substrate 5 but exceeds the melting point. When the surface melts as shown in FIG. 2 (c) and the temperature is lowered by heat dissipation thereafter, the portion is fixed as shown in FIG. 2 (d) to form a melt mark.

  When forming a scribe groove by the above processing method, if ablation processing is performed using a pulsed laser beam under a condition in which a melt mark is not formed in the scribe groove, that is, a condition in which a thermal influence is suppressed, a defect is generated along the scribe groove. Cheap. Moreover, when it becomes overmelting, a crack arises from a scribe groove | channel. Therefore, it is necessary to perform processing by setting appropriate conditions such as the output of the pulse laser beam and the scanning speed.

[Laser processing method]
In the case where scribe grooves are formed on the substrate 5 along the X direction and the Y direction orthogonal to each other, first, the pulse laser beam is condensed and irradiated onto the surface of the substrate 5. Then, this pulsed laser beam is scanned along a planned processing line in the X direction (hereinafter, this process is referred to as “1st scribe”). Thereby, a scribe groove is formed along the planned processing line in the X direction. Next, a pulsed laser beam is scanned along the processing line in the Y direction under the same conditions as the processing in the X direction (hereinafter, this process is referred to as “2nd scribe”). At this time, the irradiation of the pulse laser beam is stopped for a predetermined period within the groove width in which the scribe groove in the X direction is formed. As shown in the timing chart of FIG. 3, the temporary irradiation stop of the pulse laser beam is performed for each intersection portion of the grooves in both directions. In FIG. 3, (a) is a waveform of a pulse laser beam driving signal, “H” indicates that the pulse laser beam is off (irradiation stopped), and “L” indicates that the pulse laser beam is on (irradiation). . Further, (b) indicates that the laser output is “0” for a predetermined period for each intersection.

  When performing groove processing in the X direction and the Y direction, the substrate 5 is subjected to ablation processing using pulsed laser light, and at the same time, the substrate 5 is thermally affected to melt the processed portion to form a groove. .

[Experimental example]
-Experiment 1
FIG. 4 shows the state of the substrate surface and the sectional surface when the cross scribing is performed without controlling the pulsed laser beam (irradiation stop and restart). The pulse laser beam has a wavelength of 266 nm, an average output of 7 W, and the substrate is OA-10 (manufactured by Nippon Electric Glass Co., Ltd.) having a thickness of 0.3 mm. Further, the processing is performed from the 2nd side in the figure, the processing width is 34 μm, and the processing depth is 44 μm.

  4A shows the substrate surface before dividing, FIG. 4B shows the substrate surface after dividing, FIG. 4C shows the divided section on the 1st scribe side, and FIG. 4D shows the divided section on the 2nd scribe side.

  From Experiment 1, it was found that the following results were obtained when the pulse laser beam was not controlled.

  ・ A crack occurs in the groove (scribe line) on the 1st side.

  ・ Substrate (glass) may be fixed at the intersection, resulting in poor separation.

  -Sedge is generated at the corner of the sectional surface on the 2nd scribe side.

-Experiment 2-
FIG. 5 shows the processing state of the substrate surface when (a) and when (b) when the control (hereinafter simply referred to as “control”) is not performed. Yes. Here, processing was performed from the 1st scribe side, and pulse laser light was controlled at the intersection at the time of 2nd scribe. The conditions of the pulse laser beam, the substrate, the processing width, and the depth are the same as in Experiment 1.

  In each figure, the “command value” is a distance at which the irradiation of the pulsed laser light commanded by the control unit 10 is stopped. The actual irradiation stop distance with respect to this command value is shortened by a half of the pulse focused diameter at each of the irradiation stop position and the irradiation start position, and eventually becomes shorter than the command value by the approximate pulse focused diameter.

  From FIG. 5B, it can be seen that no crack is generated in the first scribe line by controlling the pulse laser beam. In addition, when the irradiation of the pulse laser beam is stopped and restarted in the unprocessed region where the groove is not formed by the first scribe, that is, the command value is 50 μm or more, the processing line is interrupted and chipping occurs on the 2nd scribe side.

  From the above, it is understood that when the groove processing width is 34 μm, the command value needs to be 40 μm (actual distance is 32 μm (actual measurement)) or less.

  Further, FIG. 6 shows a processing state of the sectional surface in the experiment 2 when the control of the pulse laser beam is not performed (a) and when the control is performed (b). Here, the cross sections on the 2nd scribe side are shown in comparison.

  As shown in FIG. 6B, when the pulse laser beam is controlled, when processing is performed with a command value of 20 μm or less, sores are generated at the corners of the 2nd scribe side cross section.

  From the above, it is understood that when the groove processing width is 34 μm, the command value needs to be 30 μm (the actual distance is 21 μm (actual measurement)) or more.

-Experiment 3-
FIG. 7 shows a case where processing is performed by executing control of pulsed laser light under optimum conditions.

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

  7A shows the substrate surface before dividing, FIG. 7B shows the substrate surface after dividing, FIG. 7C shows the divided section on the 1st scribe side, and FIG. 7D shows the divided section on the 2nd scribe side.

  As is apparent from these figures, no defects due to sticking of the substrate (glass) or thermal effects are observed.

[Summary]
The following can be understood by summarizing the above experimental results.

  (1) When the irradiation of the pulsed laser beam is stopped or restarted at a portion (unprocessed portion) other than the processed scribe groove, a crack is generated.

  (2) When the command value is 50 μm (actual distance 45 μm) or more, chipping occurs on the substrate surface. In addition, when the command value is 20 μm (actual distance 9 μm) or less, sores are generated at the corners of the dividing plane. Therefore, when the processing width (groove width) of the 1st scribe is 34 μm, it is necessary to set the pulse-off command value at the 2nd scribe side intersection to 30 to 40 μm (21 to 32 μm in actual distance).

  When the above is generalized, as schematically shown in FIG. 8, the region where the irradiation of the pulse laser beam on the 2nd side is stopped is within the groove width of the scribe groove on the 1st side, with the center of the groove interposed therebetween. It is optimal that the machining width (groove width) is 62 to 94%.

[Other Embodiments]
The present invention is not limited to the above-described embodiments, and various changes or modifications can be made without departing from the scope of the present invention.

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

DESCRIPTION OF SYMBOLS 1 Laser oscillator 2 Mirror mechanism 3 Lens mechanism 4 XY stage 5 Substrate 10 Control part 11 Laser control part 12 Movement control part

Claims (3)

A laser processing method for irradiating laser light along first and second scheduled processing lines intersecting a brittle material substrate surface to form a plurality of grooves on the brittle material substrate surface,
A first step of forming a groove in a first direction in the brittle material substrate by irradiating a pulsed laser beam along the first processing line;
The pulse laser beam is irradiated along the second planned processing line, and the pulse laser beam irradiation is stopped and restarted within the groove width in the first direction at a portion intersecting the groove in the first direction. A second step of forming a groove in the second direction in the brittle material substrate;
Only including,
In the second step, the laser beam irradiation is stopped within a range of 62% or more and 94% or less of the groove width in the first direction across the center of the groove in the first direction.
Laser processing method. In the first step and the second step, the brittle material substrate by melting the same time processing unit when ablation to form a groove of said first and second directions by a pulse laser beam, the laser processing according to claim 1 Method. A laser processing apparatus for irradiating a laser beam along first and second scheduled processing lines intersecting a brittle material substrate surface to form a plurality of grooves on the brittle material substrate surface,
A laser oscillator that oscillates a pulsed laser beam and a laser beam irradiation mechanism that has an optical system that collects and irradiates the oscillated pulsed laser beam;
A moving mechanism for relatively moving the laser light irradiation mechanism along the processing line on the brittle material substrate surface;
A processing control unit that controls the laser beam irradiation mechanism and the moving mechanism to form a groove that intersects the brittle material substrate;
With
The processing control unit
A first function of forming a groove in the first direction in the brittle material substrate by irradiating a pulsed laser beam along the first processing line;
The pulse laser beam is irradiated along the second planned processing line, and the pulse laser beam irradiation is stopped and restarted within the groove width in the first direction at a portion intersecting the groove in the first direction. A second function of forming a groove in the second direction of the brittle material substrate;
I have a,
In the second function, the irradiation of the laser beam is stopped within a range of 62% or more and 94% or less of the groove width in the first direction across the center of the groove in the first direction.
Laser processing equipment.