JP6682148B2 - Laser pulse cutting device and cutting method - Google Patents

Description

  The present invention relates to a laser pulse cutting device and a cutting method for cutting a plurality of laser pulses from one original laser pulse.

  A laser drill is known in which two laser pulses directed to two machining paths are cut out from one original laser pulse output from one laser oscillator to perform biaxial drilling (Patent Document 1). For cutting out the laser pulse, for example, an acousto-optic polarization element (AOD) can be used. When making a hole in a printed circuit board or the like, a laser pulse cut out from one original laser pulse and a laser pulse cut out from a subsequent original laser pulse and having different pulse widths are provided for one hole. Make it incident.

JP 2012-106266 A

  The waveform of the original laser pulse output from the laser oscillator is not rectangular, and the light intensity changes with time. When laser pulses having the same pulse width are cut out from one original laser pulse to a plurality of processing paths, the pulse energies of the laser pulses are not the same for each processing path. In order to equalize the pulse energy of the laser pulse for each processing path, the diffraction efficiency for the first processing path and the diffraction efficiency for the second processing path are made different. During the processing period, the ratio of the diffraction efficiency to the first processing path and the diffraction efficiency to the second processing path is kept constant.

  The ratio of the diffraction efficiency is set so that the pulse energies of the laser pulses directed to the first processing path and the second processing path are equal when the pulse width of the cut laser pulse has a certain value. When the pulse width of the cut laser pulse changes under the condition that the ratio of the diffraction efficiencies is kept constant, a difference occurs in the pulse energies of the laser pulses directed to the first processing path and the second processing path. I understood.

  An object of the present invention is to provide a laser pulse cutting device and a cutting method in which even if the pulse widths of laser pulses cut into a plurality of processing paths are changed, a difference in pulse energy of laser pulses between the processing paths hardly occurs. That is.

According to one aspect of the invention,
The laser beam is incident on the beam deflector by giving a command to the beam deflector that directs the incident laser beam to either the first machining path or the second machining path toward the object according to a command from the outside. A control device that cuts out a first laser pulse toward the first machining path and a second laser pulse toward the second machining path from one original laser pulse;
When changing the pulse widths of the first laser pulse and the second laser pulse, the control device uses the rising time of the original laser pulse as a reference, and the rising time and the falling time of the first laser pulse. A laser pulse slicing device that shifts both of them in opposite directions and shifts both the rising time and the falling time of the second laser pulse in opposite directions.

According to another aspect of the invention,
Cutting out a first laser pulse from the first original laser pulse toward the first processing path and cutting out a second laser pulse toward the second processing path;
A third laser pulse is cut out from the second original laser pulse having the same pulse width as that of the first original laser pulse toward the first processing path, and a third laser pulse is cut toward the second processing path. 4 has a step of cutting out a laser pulse,
When the waveform of the second original laser pulse is superimposed on the waveform of the first original laser pulse, the rising and falling edges of the waveform of the third laser pulse are the rising edges of the waveform of the first laser pulse, respectively. And the rising and falling edges of the waveform of the fourth laser pulse are opposite to the rising and falling edges of the waveform of the second laser pulse, respectively. A laser pulse cutting method is provided that is located at a directionally shifted location.

  By changing the pulse widths of the first laser pulse and the second laser pulse while maintaining the cutting efficiency at the time of cutting the laser pulse from the original laser pulse to the first processing path and the second processing path, Also, it is possible to make the pulse energies of the first laser pulse and the second laser pulse substantially equal.

FIG. 1 is a schematic diagram of a laser processing device (laser drill) in which a laser pulse cutting device according to an embodiment is used. 2A to 2D are cross-sectional views of a printed circuit board that is a processing target before processing, during processing, and at the end of processing. FIG. 3A shows the waveform of the original laser pulse output from the laser light source (FIG. 1), and the original laser pulse is cut into the first processing path and the second processing path by the laser pulse cutting device according to the embodiment. FIG. 3B is a diagram showing the waveforms of the first laser pulse and the second laser pulse, and FIG. 3B is the original laser pulse and the first laser pulse and the second laser pulse cut out by the laser pulse cutting device according to the comparative example. It is a figure which shows the waveform of. FIG. 4 is a diagram showing the waveforms of the first laser pulse and the second laser pulse and the waveform of the original laser pulse that are cut out by using the laser pulse cutting device according to the modification. FIG. 5: is a figure which shows the waveform of the 1st laser pulse and 2nd laser pulse which are cut out using the laser pulse cutting device by another modification, and the waveform of the original laser pulse.

  A laser pulse cutting device according to an embodiment will be described with reference to FIGS. 1 to 3B.

  FIG. 1 is a schematic diagram of a laser processing device (laser drill) in which a laser pulse cutting device according to an embodiment is used. The laser light source 10 receives the oscillation command signal S0 from the control device 55, laser-oscillates, and outputs the pulsed laser beam PLB. For the laser light source 10, for example, a carbon dioxide gas laser is used. For example, the start of oscillation is instructed by the rise of the oscillation command signal S0, and the stop of oscillation is instructed by the fall of the oscillation command signal S0.

  A beam deflector 20 is arranged in the path of the pulsed laser beam PLB output from the laser light source 10 and passing through the optical system 11. For the beam deflector 20, for example, an acousto-optic deflecting element (AOD) can be used. The optical system 11 includes, for example, a beam expander and an aperture. The beam deflector 20 redirects the incident laser beam to any one of the damper path PD, the first processing path MP1, and the second processing path MP2 toward the beam damper 13. The beam deflector 20 includes an acousto-optic crystal 21, a transducer 22, and a driver 23. The transducer 22 is driven by the driver 23 to generate an elastic wave in the acousto-optic crystal 21.

  The driver 23 is provided with a path switching terminal 24, a cutout terminal 25, a first diffraction efficiency adjustment knob 26, and a second diffraction efficiency adjustment knob 27. The route selection signal S1 is input from the control device 55 to the route switching terminal 24. One of the first machining path MP1 and the second machining path MP2 is selected by the path selection signal S1. The cutout signal S2 is input from the control device 55 to the cutout terminal 25. The beam deflector 20 directs the incident laser beam to the damper path PD while the cutout signal S2 is not input. While the cutout signal S2 is being input, the beam deflector 20 directs the laser beam to one of the first processing path MP1 and the second processing path MP2 that is selected by the path selection signal S1. . When the control device 55 transmits the cutout signal S2 to the beam deflector 20, the laser pulse is output from the original laser pulse output from the laser light source 10 to one of the first processing path MP1 and the second processing path MP2. Can be cut out.

  The first diffraction efficiency adjustment knob 26 can adjust the diffraction efficiency when the input laser beam is directed to the first processing path MP1. The second diffraction efficiency adjustment knob 27 can adjust the diffraction efficiency when the input laser beam is directed to the second processing path MP2. In this way, the beam deflector 20 has a function of independently adjusting the diffraction efficiency for the first processing path MP1 and the diffraction efficiency for the second processing path MP2. By adjusting the diffraction efficiency, the light intensity (power) of the laser beam directed to the first processing path MP1 and the second processing path MP2 can be adjusted. In other words, by independently adjusting the diffraction efficiency, it is possible to adjust the ratio between the attenuation rate of the laser pulse cut out to the first processing path MP1 and the attenuation rate of the laser pulse cut out to the second processing path MP2. .

  The control device 55 and the beam deflector 20 function as a laser pulse cutting device that cuts out a laser pulse directed to the first processing path MP1 and a laser pulse directed to the second processing path MP2 from each laser pulse of the pulsed laser beam PLB. To do.

  The laser beam output to the first processing path MP1 is reflected by the mirror 30 and enters the beam scanner 31. The beam scanner 31 changes the traveling direction of the laser beam into a two-dimensional direction. For the beam scanner 31, for example, a pair of galvano scanners can be used. The laser beam deflected by the beam scanner 31 is converged by the fθ lens 32 and then enters the object 33 to be processed. Similarly, the laser beam output to the second processing path MP2 enters the object to be processed 43 via the mirror 40, the beam scanner 41, and the fθ lens 42. The processing objects 33 and 43 are held on the stage 50.

  The beam scanners 31 and 41 operate to receive the control signals G1 and G2 from the control device 55, respectively, so that the laser beam is incident on the commanded target position. When the incident position of the laser beam is set to the commanded target position, the controller 55 is notified of the completion of settling.

  The display device 56 displays an image under the control of the control device 55. The operator operates the input device 57 to input various control parameters for performing laser processing. The control device 55 acquires the control parameter input from the input device 57 and stores it in the storage device. As the display device 56, for example, a liquid crystal display or the like is used. As the input device 57, for example, a keyboard, a pointing device, or the like is used. A touch panel may be used for the display device 56 and the input device 57.

  2A to 2D are cross-sectional views of the printed circuit board 60, which is an object to be processed, before processing, during processing, and at the end of processing. 2A to 2D show an example of performing processing with a laser pulse directed to the first processing path MP1 (FIG. 1). Also in the second machining path MP2 (FIG. 1), drilling is performed in the same process as the process shown in FIGS. 2A to 2D.

  As shown in FIG. 2A, the printed board 60 has a three-layer structure in which a front surface copper layer 62, a resin layer 61, and a bottom surface copper layer 63 are laminated. As shown in FIG. 2B, the laser pulse LP11 is incident on the surface copper layer 62 to form the recess 65. The concave portion 65 penetrates the surface copper layer 62 and reaches the middle of the resin layer 61 in the depth direction. The laser pulse LP11 is cut out from the original laser pulse output from the laser light source 10. From the original laser pulse obtained by cutting out the laser pulse LP11, a laser pulse directed toward the second processing path MP2 is further cut out, and similar processing is performed also at the second processing path MP2.

  As shown in FIG. 2C, the recess 65 is deepened by making the laser pulse LP12 incident on the bottom surface of the recess 65. At this point, the concave portion 65 has not reached the bottom copper layer 63. The laser pulse LP12 is cut out from another original laser pulse following the original laser pulse cut out from the laser pulse LP11 (FIG. 2B). From this original laser pulse, a laser pulse further directed to the second machining path MP2 is cut out, and the same machining is performed on the second machining path MP2.

  As shown in FIG. 2D, the laser pulse LP13 is incident on the bottom surface of the recess 65 to make the recess 65 deeper. At this point, the recess 65 reaches the bottom copper layer 63, and a blind via hole is formed. The laser pulse LP13 is cut out from another original laser pulse following the original laser pulse from which the laser pulse LP12 (FIG. 2C) is cut out. From this original laser pulse, a laser pulse further directed to the second machining path MP2 is cut out, and the same machining is performed on the second machining path MP2.

  Laser pulse LP11 (FIG. 2B) has a pulse energy capable of penetrating surface copper layer 62. The pulse energy of laser pulse LP12 (FIG. 2C) is smaller than the pulse energy of laser pulse LP11. The pulse energy of the laser pulse LP12 is set to such a magnitude that the concave portion 65 does not reach the bottom surface copper layer 63 and the resin layer 61 can be dug forward. The pulse energy of the laser pulse LP13 (FIG. 2D) is equal to the pulse energy of the laser pulse LP12 (FIG. 2C).

  In the example shown in FIGS. 2A to 2D, one blind via hole is formed by three laser pulses LP11, LP12, and LP13, but one blind via hole may be processed by using four or more laser pulses. . The number of laser pulses used for processing and the pulse energies of the laser pulses LP12 and LP13 are adjusted according to the thickness of the resin layer 61, and are optimized from the viewpoint of reducing damage given to the bottom surface copper layer 63. For example, the pulse energy of the laser pulse LP13 may be sufficient to expose the bottom surface copper layer 63, and may be smaller than the pulse energy of the laser pulse LP12. By reducing the pulse energy of the laser pulse LP13, the damage given to the bottom surface copper layer 63 can be reduced.

  FIG. 3A is a waveform of the original laser pulse LO output from the laser light source 10 (FIG. 1), and the first laser path LO cut out into the first processing path MP1 and the second processing path MP2 (FIG. 1), respectively. It is a figure which shows the waveform of 1st laser pulse LP1 and 2nd laser pulse LP2.

  As shown in the upper part of FIG. 3A, the original laser pulse LO rises at the rising time point t0 and sharply falls from the falling time point t5. The slope of the light intensity from the rising time point t0 to the falling time point t5 is not constant, and the slope becomes gentle over time. The control device 55 cuts out the first laser pulse LP1 toward the first machining path MP1 from the first half of the original laser pulse LO, and the second laser pulse LP2 toward the second machining path MP2 from the latter half of the original laser pulse LO. The laser pulse LP2 of is cut out. The pulse width of the first laser pulse LP1 and the pulse width of the second laser pulse LP2 are the same.

  The diffraction efficiency of the beam deflector 20 toward the first processing path MP1 is set to 100%. Therefore, the light intensity (waveform height) of the first laser pulse LP1 matches the light intensity (waveform height) of the original laser pulse LO. The diffraction efficiency of the beam deflector 20 toward the second processing path MP2 is set to less than 100%. Therefore, the light intensity (waveform height) of the second laser pulse LP2 is lower than the light intensity (waveform height) of the original laser pulse LO. The ratio of the diffraction efficiency to the first processing path MP1 and the diffraction efficiency to the second processing path MP2 is equal to the pulse energy of the first laser pulse LP1 and the pulse energy of the second laser pulse LP2. Is set to. The pulse energy of the laser pulse corresponds to the area of the pulse waveform (a value obtained by integrating the pulse waveform over time).

  The lower part of FIG. 3A shows an example in which the pulse widths of the first laser pulse LP1 and the second laser pulse LP2 are shorter than those shown in the upper part. The control device 55 shifts the rising time point t1 of the first laser pulse LP1 backward and the falling time point t2 with respect to the rising time point t0 of the original laser pulse LO, as compared to the pulse waveform shown in the upper part of FIG. 3A. Is shifted forward to shorten the pulse width of the first laser pulse LP1. Similarly, by using the rising time point t0 of the original laser pulse LO as a reference, the rising time point t3 of the second laser pulse LP2 is shifted backward and the falling time point t4 is shifted forward, whereby the second laser pulse LP2 Shorten the pulse width.

  When the pulse width of the first laser pulse LP1 is lengthened, the rising time point t1 of the first laser pulse LP1 may be shifted forward and the falling time point t2 may be shifted backward. Similarly, when the pulse width of the second laser pulse LP2 is lengthened, the rising time point t3 of the second laser pulse LP2 may be shifted forward and the falling time point t4 may be shifted backward.

  As described above, the control device 55 changes the pulse widths of the first laser pulse LP1 and the second laser pulse LP2 by shifting the rising time and the falling time of the laser pulse in mutually opposite directions. To do. At this time, when the waveform of the original laser pulse LO in the lower stage of FIG. 3A is superimposed on the waveform of the original laser pulse LO in the upper stage, the rising and falling edges of the waveform of the first laser pulse LP1 in the lower stage are respectively the first in the upper stage. Is located at a position where the rising and falling edges of the waveform of the laser pulse LP1 are shifted in mutually opposite directions, and the rising and falling edges of the waveform of the second laser pulse LP2 in the lower stage are respectively the second laser pulse in the upper stage. It is located at a position where the rising and falling edges of the Lp2 waveform are shifted in opposite directions.

  Next, the excellent effect of the example shown in FIG. 3A will be described in comparison with the comparative example shown in FIG. 3B.

  FIG. 3B is a waveform of the original laser pulse LO, and a first laser pulse LP1 and a second laser which are cut out from the original laser pulse LO into the first processing path MP1 and the second processing path MP2 by the method according to the comparative example. It is a figure which shows the waveform of pulse LP2.

  The waveform shown in the upper part of FIG. 3B is the same as the waveform shown in the upper part of FIG. 3A. Diffraction of the beam deflector 20 (FIG. 1) is performed so that the pulse energy of the first laser pulse LP1 becomes equal to the pulse energy of the second laser pulse LP2 when the pulse width is shown in the upper part of FIG. 3B. Efficiency is regulated.

  The lower part of FIG. 3B shows an example in which the pulse widths of the first laser pulse LP1 and the second laser pulse LP2 are shorter than those shown in the upper part. The rising time t1 of the first laser pulse LP1 is fixed with reference to the rising time t0 of the original laser pulse LO, and only the falling time t2 is shifted forward. Similarly, the rising time point t3 of the second laser pulse LP2 is fixed, and only the falling time point t4 is shifted forward.

  The slope of the waveform of the original laser pulse LO at the position where the first laser pulse LP1 is cut out is steeper than the slope of the waveform of the original laser pulse LO at the position where the second laser pulse LP2 is cut out. Therefore, when the pulse width is shortened by the method according to the comparative example, the pulse energy of the first laser pulse LP1 is reduced more than the pulse energy of the second laser pulse LP2. If the diffraction efficiency of the beam deflector 20 (FIG. 1) is unchanged, the pulse energy of the first laser pulse LP1 becomes smaller than the pulse energy of the second laser pulse LP2. When the pulse energy of the first laser pulse LP1 and the pulse energy of the second laser pulse LP2 are different, it is possible to perform processing with the same quality on the first processing path MP1 and the second processing path MP2. It's gone.

  Each time the pulse widths of the first laser pulse LP1 and the second laser pulse LP2 are changed, the diffraction efficiency of the first processing path MP1 and the second processing path MP2 is modified to obtain the first laser pulse. It is possible to equalize the pulse energy of LP1 and the pulse energy of the second laser pulse LP2. However, it is difficult to readjust the diffraction efficiency each time the pulse widths of the first laser pulse LP1 and the second laser pulse LP2 are changed.

  When the pulse width is changed, it is preferable to keep the pulse energy of the first laser pulse LP1 and the pulse energy of the second laser pulse LP2 substantially equal to each other without readjusting the diffraction efficiency.

  In the embodiment shown in FIG. 3A, when the pulse widths of the first laser pulse LP1 and the second laser pulse LP2 are changed, both the rising time and the falling time of the laser pulse are shifted in opposite directions. Let Therefore, the difference between the change rate of the pulse energy of the first laser pulse LP1 and the change rate of the pulse energy of the second laser pulse LP2 when changing the pulse width is smaller than that in the comparative example. . As a result, it is possible to reduce variations in processing quality between the first processing path MP1 and the second processing path MP2.

  Next, with reference to FIG. 4, a cutting method by the laser pulse cutting device according to the modification of the above embodiment will be described.

  FIG. 4 is a diagram showing the waveforms of the first laser pulse LP1 and the second laser pulse LP2 and the waveform of the original laser pulse LO that are cut out by using the laser pulse cutting device according to the modified example. In this modified example, a first reference time point tr1 and a second reference time point tr2 fixed within the pulse width of the original laser pulse LO are set. For example, the elapsed time from the rise time t0 of the original laser pulse LO to the first reference time tr1 and the second reference time tr2 is constant for all the original laser pulses LO.

  The first reference time point tr1 and the second reference time point tr2 are the value H1 obtained by multiplying the height of the waveform of the original laser pulse LO at the first reference time point tr1 by the diffraction efficiency to the first machining path MP1, and The value H2 obtained by multiplying the height of the waveform of the original laser pulse LO at the second reference time tr2 by the diffraction efficiency of the second processing path MP2 is set to be equal.

  When changing the pulse widths of the first laser pulse LP1 and the second laser pulse LP2, the control device 55 includes the first reference time point tr1 within the pulse width of the first laser pulse LP1. The rising time point and the falling time point of each laser pulse are shifted so that the second reference time point tr2 is included in the pulse width of the laser pulse LP2.

  As shown in the upper part of FIG. 4, the control device 55 controls the time width TF of the waveform of the first laser pulse LP1 that extends forward from the first reference time point tr1 and the first laser pulse LP1 that extends backward. The first laser pulse LP1 is cut out so that the time width TB of the waveform becomes equal. Similarly, the time width TF of the waveform of the second laser pulse LP2 that extends forward from the second reference time point tr2 and the time width TB of the waveform of the second laser pulse LP2 that extends rearward become equal. , The second laser pulse LP2 is cut out. The time width TF of the first laser pulse LP1 is equal to the time width TF of the second laser pulse LP2, and the time width TB of the first laser pulse LP1 is equal to the time width TB of the second laser pulse LP2.

  When the pulse width is shortened, as shown in the lower part of FIG. 4, the time width TF of the waveform of the first laser pulse LP1 that extends forward from the first reference time point tr1 and the first laser pulse that extends backward. The time width TB of the waveform of LP1 is shortened. Similarly, the time width TF of the waveform of the second laser pulse LP2 that extends forward from the second reference time tr2 and the time width TB of the waveform of the second laser pulse LP2 that extends backward are shortened. At this time, the control device 55 shortens the pulse width while maintaining the condition that the time width TF and the time width TB are equal.

  Next, a method of determining the first reference time point tr1 and the second reference time point tr2 will be described. First, the maximum value of the pulse width of the laser pulse required for drilling is determined. For example, the maximum value of the pulse width of the first laser pulse LP1 and the second laser pulse LP2 is calculated from the pulse energy required to form the recess 65 (FIG. 2B) that penetrates the surface copper layer 62 (FIG. 2A). You can decide.

  The pulse width of the original laser pulse LO (FIG. 4) is determined based on the maximum value of the pulse widths of the first laser pulse LP1 and the second laser pulse LP2. The pulse width of the original laser pulse LO is, for example, the waiting time width required from the rising time point of the original laser pulse LO to the rising time point of the first laser pulse LP1, or from the falling time point of the first laser pulse LP1 to the second waiting time width. The waiting time width required until the rising time point of the laser pulse LP2 and the waiting time width necessary from the falling time point of the second laser pulse LP2 to the falling time point of the original laser pulse LO are the first laser pulse LP1 and It can be determined by adding the maximum value of the pulse width of the second laser pulse LP2.

  The first reference time tr1 is the center point on the time axis of the waveform of the first laser pulse LP1 when the first laser pulse LP1 and the second laser pulse LP2 having the maximum pulse width are cut out from the original laser pulse LO. Then, the center point of the waveform of the second laser pulse LP2 on the time axis may be set as the second reference time point tr2. If the diffraction efficiency of the beam deflector 20 is set based on the ratio of the height of the waveform of the original laser pulse LO at the first reference time tr1 to the height of the waveform of the original laser pulse LO at the second reference time tr2. Good.

  The above three waiting time widths are set in the control device 55 in advance. When the operator operates the input device 57 to input the maximum value of the pulse width of the laser pulse required for processing, the control device 55 determines the maximum value of the input pulse width and the preset waiting time width. Then, the pulse width of the original laser pulse LO, the first reference time point tr1 and the second reference time point tr2 are calculated.

  In the modification shown in FIG. 4, even when the pulse widths of the first laser pulse LP1 and the second laser pulse LP2 are changed, the center of the waveform of the first laser pulse LP1 on the time axis is the first reference. It is fixed at the time point tr1 and the center of the waveform of the second laser pulse LP2 on the time axis is fixed at the second reference time point tr2. Therefore, even if the pulse width is changed, the light intensity (the height of the laser pulse waveform) at the center position on the time axis of the waveforms of the first laser pulse LP1 and the second laser pulse LP2 does not change. Therefore, in the modification shown in FIG. 4, even if the pulse widths of the first laser pulse LP1 and the second laser pulse LP2 are changed, the pulse energies of the both can be maintained substantially equal.

  Next, with reference to FIG. 5, a cutting method by a laser pulse cutting device according to another modification of the above embodiment will be described.

  FIG. 5 is a diagram showing the waveforms of the first laser pulse LP1 and the second laser pulse LP2 and the waveform of the original laser pulse LO that are cut out using the laser pulse cutting device according to the present modification.

  In this modification as well, similar to the modification shown in FIG. 4, the first reference time tr1 and the second reference time tr2 fixed within the pulse width of the original laser pulse LO are set.

  As shown in the upper part of FIG. 5, the control device 55 (FIG. 1) multiplies the height H1 of the waveform of the first laser pulse LP1 at the first reference time tr1 by the pulse width PW of the first laser pulse. The first laser pulse LP1 is cut out so that the value H1 × PW is equal to the area A1 of the waveform of the first laser pulse LP1. When the waveform of the original laser pulse LO has a linear slope, the first reference time point tr1 is located at the center of the period from the rise to the fall of the first laser pulse LP1. Actually, since the waveform of the original laser pulse LO is a curve, strictly speaking, the first reference time point tr1 deviates from the center of the period from the rise to the fall of the first laser pulse LP1. The same applies to the relationship between the second laser pulse LP2 and the second reference time point tr2. That is, the value H2 × PW obtained by multiplying the height H2 of the waveform of the second laser pulse LP2 at the second reference time tr2 by the pulse width PW of the second laser pulse, and the area of the waveform of the second laser pulse LP2. A2 is equal.

  As shown in the lower part of FIG. 5, even when the pulse widths of the first laser pulse LP1 and the second laser pulse LP2 are shortened, the relationship between the first laser pulse LP1 and the first reference time point tr1 and The relationship between the second laser pulse LP2 and the second reference time point tr2 satisfies the above condition. That is, H1 × PW is equal to the waveform area A1 of the first laser pulse LP1, and H2 × PW is equal to the waveform area A2 of the second laser pulse LP2.

  Under the condition that the waveform of the original laser pulse LO of the cutout source is almost constant, the height of the waveform at the first reference time tr1 and the second reference time tr2 is almost constant. Therefore, when the pulse widths of the first laser pulse LP1 and the second laser pulse LP2 are changed by the method according to the present modification, the pulse energies of the two after the pulse width change become substantially the same.

  In the above-described embodiment and modification, laser pulses are cut out from one original laser pulse LO into two processing paths, respectively, but laser pulses may be cut out into three or more processing paths. Also in this case, when the pulse width of the cut-out laser pulse is changed, the rising and falling points of the cut-out laser pulse may be shifted in the same manner as in the above-described embodiment or modification.

  Needless to say, each of the above-described embodiments is merely an example, and partial replacement or combination of the configurations shown in different embodiments is possible. The same effects by the same configurations of the plurality of embodiments will not be sequentially described for each embodiment. Furthermore, the invention is not limited to the embodiments described above. For example, it will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

10 Laser Light Source 11 Optical System 13 Beam Damper 20 Beam Deflector 21 Acousto-Optical Crystal 22 Transducer 23 Driver 24 Path Switching Terminal 25 Cutout Terminal 26 First Diffraction Efficiency Adjustment Knob 27 Second Diffraction Efficiency Adjustment Knob 30 Mirror 31 Beam Scanner 32 fθ lens 33 object to be processed 40 mirror 41 beam scanner 42 fθ lens 43 object to be processed 50 stage 55 controller 56 display device 57 input device 60 printed circuit board 61 resin layer 62 surface copper layer 63 bottom copper layer 65 recess LO original laser pulse LP1 First laser pulse LP2 Second laser pulse

Claims (5)

The laser beam is incident on the beam deflector by giving a command to the beam deflector that directs the incident laser beam to either the first machining path or the second machining path toward the object according to a command from the outside. A control device that cuts out a first laser pulse toward the first machining path and a second laser pulse toward the second machining path from one original laser pulse;
When changing the pulse widths of the first laser pulse and the second laser pulse, the control device uses the rising time of the original laser pulse as a reference, and the rising time and the falling time of the first laser pulse. Both of them are shifted in opposite directions to each other, and both the rising time and the falling time of the second laser pulse are shifted in opposite directions.   In the control device, the first reference time point and the second reference time point fixed within the pulse width of the original laser pulse are included in the pulse widths of the first laser pulse and the second laser pulse, respectively. And the height of the waveform of the first laser pulse at the first reference time point is equal to the height of the waveform of the second laser pulse at the second reference time point. The laser pulse cutting device according to claim 1, wherein the pulse width of the second laser pulse is changed.   The control device makes the time width of the waveform of the first laser pulse extending forward from the first reference time point equal to the time width of the waveform of the first laser pulse extending backward, The first laser pulse is so arranged that the time width of the waveform of the second laser pulse extending forward from the second reference time point and the time width of the waveform of the second laser pulse extending rearward are equal. The laser pulse cutting device according to claim 2, wherein the pulse width of the second laser pulse is changed.   The control device has a value obtained by multiplying the height of the waveform of the first laser pulse by the pulse width of the first laser pulse at the first reference time point, and the area of the waveform of the first laser pulse. Are equal to each other, and the value obtained by multiplying the height of the waveform of the second laser pulse at the second reference time by the pulse width of the second laser pulse and the area of the waveform of the second laser pulse are The laser pulse cutting device according to claim 2, wherein the pulse widths of the first laser pulse and the second laser pulse are changed so as to be equal to each other. Cutting out a first laser pulse from the first original laser pulse toward the first processing path and cutting out a second laser pulse toward the second processing path;
A third laser pulse is cut out from the second original laser pulse having the same pulse width as that of the first original laser pulse toward the first processing path, and a third laser pulse is cut toward the second processing path. 4 has a step of cutting out a laser pulse,
When the waveform of the second original laser pulse is superimposed on the waveform of the first original laser pulse, the rising and falling edges of the waveform of the third laser pulse are the rising edges of the waveform of the first laser pulse, respectively. And the rising and falling edges of the waveform of the fourth laser pulse are opposite to the rising and falling edges of the waveform of the second laser pulse, respectively. A laser pulse cutting method located at a position shifted in the direction.

Images