KR102287590B1 - Laser pulse cutting device and cutting method - Google Patents

Abstract

When the control device gives a command to the beam deflector, the first laser pulse toward the first processing path and the second laser pulse toward the second processing path are cut out from one original laser pulse incident on the beam deflector. When changing the pulse widths of the first laser pulse and the second laser pulse, the control device sets both the rising time and the falling time of the first laser pulse in opposite directions based on the rising time of the original laser pulse. shift, and both the rising time and the falling time of the second laser pulse are shifted in opposite directions.

Description

Laser pulse cutting device and cutting method

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

A laser drill that cuts out two laser pulses directed to two processing paths from one original laser pulse output from one laser oscillator and performs punching in two axes is known (Patent Document 1). For cutting the laser pulse, for example, an acousto-optical polarization device (AOD) can be used. When punching is performed on a printed circuit board or the like, a laser pulse cut out from one original laser pulse and a laser pulse having a different pulse width cut out from a subsequent original laser pulse are made incident on one hole.

Patent Document 1: Japanese Patent Application Laid-Open No. 2012-106266

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

When the pulse width of the cut laser pulse is a predetermined value, the ratio of the diffraction efficiency is set so that the pulse energy of the laser pulses directed to the first processing path and the second processing path becomes the same. It was found that, under the condition that the ratio of diffraction efficiency is kept constant, when the pulse width of the cut laser pulse is changed, the pulse energy of the laser pulse directed to the first processing path and the second processing path is different.

It is an object of the present invention to provide a laser pulse cutting apparatus and a cutting method in which a difference in pulse energy of a laser pulse for each processing path is unlikely to occur even when the pulse width of a laser pulse cut by a plurality of processing paths is changed.

According to one aspect of the present invention,

By giving a command to a beam deflector that switches an incident laser beam to either one of a first processing path and a second processing path toward the object in response to a command from the outside, from one original laser pulse incident to the beam deflector , a control device for cutting a first laser pulse toward the first processing path, and a second laser pulse toward the second processing path,

The control device, when changing the pulse widths of the first laser pulse and the second laser pulse, based on the rising time of the original laser pulse, both the rising time and the falling time of the first laser pulse , and shifting in opposite directions, and shifting both the rising and falling timing of the second laser pulse in opposite directions is provided.

According to another aspect of the present invention,

A step of cutting the first laser pulse from the first original laser pulse toward the first processing path and cutting the second laser pulse toward the second processing path;

From the second original laser pulse having the same pulse width as the first original laser pulse, the third laser pulse is cut toward the first processing path, and the fourth laser pulse is cut toward the second processing path. have fairness,

When the waveform of the second primary laser pulse is superimposed on the waveform of the first primary laser pulse, the rising and falling of the waveform of the third laser pulse respectively reverse the rising and falling of the waveform of the first laser pulse. The laser pulse cutting method is located at a position shifted in the direction, and the rising and falling of the waveform of the fourth laser pulse is located at a position where the rising and falling of the waveform of the second laser pulse are shifted in opposite directions, respectively is provided

Even if the pulse width of the first laser pulse and the second laser pulse is changed, the first laser pulse is maintained in a state where the cutting efficiency when cutting the laser pulse from the original laser pulse to the first processing path and the second processing path is kept constant. It is possible to approximately equalize the pulse energy of and the second laser pulse.

1 is a schematic diagram of a laser processing apparatus (laser drill) in which a laser pulse cutting apparatus according to an embodiment is used.
In Fig. 2, Figs. 2A to 2D are cross-sectional views of a printed circuit board as a processing object before processing, during processing, and at the end of processing.
In Figure 3, Figure 3a, the waveform of the original laser pulse output from the laser light source (Figure 1), and the first processing path and the second processing path from the original laser pulse, by the laser pulse cutting device according to the embodiment It is a diagram showing the waveforms of the first laser pulse and the second laser pulse to be cut, respectively, and FIG. 3B is the first laser pulse and the second laser pulse cut by the laser pulse cutting device according to the comparative example and the original laser pulse. It is a diagram showing the waveform.
FIG. 4 is a diagram showing waveforms of first and second laser pulses cut out using a laser pulse cutting device according to a modified example, and waveforms of original laser pulses.
5 is a diagram illustrating waveforms of a first laser pulse and a second laser pulse cut out using a laser pulse cutting device according to another modified example, and waveforms of the original laser pulse.

1 to 3b, a laser pulse cutting apparatus according to an embodiment will be described.

1 is a schematic diagram of a laser processing apparatus (laser drill) in which a laser pulse cutting apparatus 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 a pulsed laser beam PLB. For the laser light source 10, for example, a carbon dioxide laser is used. For example, when the oscillation command signal S0 is activated, oscillation start is commanded, and when the oscillation command signal S0 ends, the oscillation stop is commanded.

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-optical deflection device (AOD) can be used. The optical system 11 includes, for example, a beam expander, an aperture, and the like. The beam deflector 20 converts the incident laser beam into any one of a damper path PD, a first processing path MP1, and a second processing path MP2 directed toward the beam damper 13 . The beam deflector 20 includes an acoustooptic crystal 21 , a transducer 22 , and a driver 23 . The transducer 22 is driven by the driver 23 to generate an acoustic wave in the acoustooptic crystal 21 .

The driver 23 is provided with a path switching terminal 24 , a cutting terminal 25 , a first diffraction efficiency adjusting knob 26 , and a second diffraction efficiency adjusting knob 27 . A path selection signal S1 is input from the control device 55 to the path switching terminal 24 . According to the path selection signal S1, one of the first machining path MP1 and the second machining path MP2 is selected. A cutting signal S2 is input from the control device 55 to the cutting terminal 25 . During the period in which the cutting signal S2 is not input, the beam deflector 20 switches the incident laser beam to the damper path PD. During the period in which the cutting signal S2 is input, the beam deflector 20 switches the laser beam to the path selected by the path selection signal S1 among the first processing path MP1 and the second processing path MP2. The control device 55 transmits the cutting signal S2 to the beam deflector 20, so that, from the original laser pulse output from the laser light source 10, a laser pulse is generated in one of the first processing path MP1 and the second processing path MP2. can be cut

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

The control device 55 and the beam deflector 20 are laser pulse cutting devices for cutting out laser pulses from each laser pulse of the pulsed laser beam PLB toward the first processing path MP1 and laser pulses toward the second processing path MP2. function

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

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

The display device 56 displays an image under control from the control device 55 . The operator operates the input device 57 to input various control parameters for laser processing. The control device 55 acquires the control parameters inputted from the input device 57 and stores them in a storage device. For 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 as a processing object before processing, during processing, and at the end of processing. 2A to 2D show examples of processing with laser pulses directed to the first processing path MP1 (FIG. 1). Also in the second machining path MP2 (FIG. 1), punching is performed in the same process as the steps shown in FIGS. 2A to 2D.

As shown in Fig. 2A, the printed circuit board 60 has a three-layer structure in which a surface copper layer 62, a resin layer 61, and a bottom copper layer 63 are laminated. As shown in FIG. 2B, the recessed part 65 is formed by making the laser pulse LP11 inject into the surface copper layer 62. As shown in FIG. The recessed 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 from which the laser pulse LP11 was cut, a laser pulse directed further toward the second processing path MP2 is cut out, and the same processing is performed in the second processing path MP2.

As shown in FIG. 2C, the recessed part 65 is deepened by making the laser pulse LP12 incident on the bottom surface of the recessed part 65. As shown in FIG. At this point, the concave portion 65 has not reached the bottom copper layer 63 . The laser pulse LP12 is cut out from the other original laser pulses following the original laser pulse from which the laser pulse LP11 (FIG. 2B) was cut out. A laser pulse directed further toward the second processing path MP2 is cut from the original laser pulse, and the same processing is performed in the second processing path MP2.

As shown in FIG. 2D , the concave portion 65 is made deeper by making the laser pulse LP13 incident on the bottom surface of the concave portion 65 . At this point, the concave portion 65 reaches the bottom copper layer 63, and a blind via hole is formed. The laser pulse LP13 is cut out from the other original laser pulses following the original laser pulse from which the laser pulse LP12 (FIG. 2C) was cut out. A laser pulse directed further toward the second processing path MP2 is cut from the original laser pulse, and the same processing is performed in the second processing path MP2.

The laser pulse LP11 (FIG. 2B) has pulse energy capable of penetrating the surface copper layer 62 . The pulse energy of the laser pulse LP12 (FIG. 2C) is smaller than the pulse energy of the laser pulse LP11. The pulse energy of the laser pulse LP12 is set so that the concave portion 65 does not reach the bottom copper layer 63 and can penetrate the resin layer 61 . The pulse energy of the laser pulse LP13 (FIG. 2D) is the same as that of the laser pulse LP12 (FIG. 2C).

In the example shown in FIGS. 2A to 2D, one blind via hole is formed with three laser pulses LP11, LP12, and LP13. However, there is a case where one blind via hole is processed 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 to the bottom copper layer 63 . For example, the pulse energy of the laser pulse LP13 may be sufficient to expose the bottom 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 to the bottom copper layer 63 can be reduced.

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

As shown in the upper part of FIG. 3A, the original laser pulse LO rises at the rising time t0, and falls rapidly from the falling time t5. The slope of the light intensity from the rising time t0 to the falling time t5 is not constant, and the slope becomes gentle with the lapse of time. The control device 55 cuts out the first laser pulse LP1 directed toward the first processing path MP1 from the first half of the original laser pulse LO, and from the second half of the original laser pulse LO toward the second processing path MP2 Cut out the laser pulse LP2. The pulse width of the first laser pulse LP1 is the same as that of the second laser pulse LP2.

The diffraction efficiency of the beam deflector 20 to the first processing path MP1 is set to 100%. For this reason, the light intensity (height of the waveform) of the first laser pulse LP1 coincides with the light intensity (height of the waveform) of the original laser pulse LO. The diffraction efficiency of the second processing path MP2 by the beam deflector 20 is set to less than 100%. For this reason, the light intensity (height of the waveform) of the second laser pulse LP2 is lower than the light intensity (height of the waveform) 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 set so that the pulse energy of the first laser pulse LP1 and the pulse energy of the second laser pulse LP2 are equal. The pulse energy of the laser pulse corresponds to the area of the pulse waveform (the value obtained by integrating the pulse waveform with time).

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 is shown in the lower part of FIG. 3A. The control device 55 shifts the rising time t1 of the first laser pulse LP1 backwards on the basis of the rising time t0 of the original laser pulse LO as compared to the pulse waveform shown in the upper part of FIG. 3A , and the falling time t2 By shifting forward, the pulse width of the first laser pulse LP1 is shortened. Similarly, based on the rising time t0 of the original laser pulse LO, the rising time t3 of the second laser pulse LP2 is shifted backward, and the falling time t4 is shifted forward, thereby shortening the pulse width of the second laser pulse LP2. .

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

As described above, the control device 55 changes the pulse widths of the first laser pulses LP1 and the second laser pulses LP2 by shifting the rising and falling times of the laser pulses in opposite directions. At this time, when the waveform of the original laser pulse LO at the bottom of FIG. 3a is superimposed on the waveform of the original laser pulse LO at the top, the rising and falling of the waveform of the first laser pulse LP1 at the bottom, respectively, the first laser pulse LP1 at the top It is located at a position where the rising and falling of the waveform of LP2 are shifted in opposite directions, and the rising and falling of the waveform of the second laser pulse LP2 at the lower end respectively cause the rising and falling of the waveform of the upper second laser pulse LP2 in opposite directions. It is located at the position shifted to

Next, the excellent effect of the Example shown in FIG. 3A is demonstrated in contrast with the comparative example shown in FIG. 3B.

Figure 3b shows the waveform of the original laser pulse LO, and the first laser pulse LP1 and the second laser pulse LP2 cut out by the method according to the comparative example from the original laser pulse LO to the first processing path MP1 and the second processing path MP2. It is a diagram showing the waveform.

The waveform shown in the upper part of FIG. 3B is the same as the waveform shown in the upper part of FIG. 3A. The diffraction efficiency of the beam deflector 20 (FIG. 1) is adjusted so that the pulse energy of the first laser pulse LP1 and the pulse energy of the second laser pulse LP2 are equal to the pulse width shown in the upper part of FIG. 3B.

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 is shown in the lower part of FIG. 3B. Based on the rising time t0 of the original laser pulse LO, the rising time t1 of the first laser pulse LP1 is fixed, and only the falling time t2 is shifted forward. Similarly, the rising time t3 of the second laser pulse LP2 is fixed, and only the falling time 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 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. For this reason, when the pulse width is shortened by the method according to the comparative example, the pulse energy of the first laser pulse LP1 is significantly reduced compared to the pulse energy of the second laser pulse LP2. If the diffraction efficiency of the beam deflector 20 (FIG. 1) is constant, the pulse energy of the first laser pulse LP1 becomes smaller than the pulse energy of the second laser pulse LP2. If the pulse energy of the first laser pulse LP1 and the pulse energy of the second laser pulse LP2 are different, processing of the same quality cannot be performed by the first processing path MP1 and the second processing path MP2.

Whenever 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 corrected, so that the pulse energy of the first laser pulse LP1 and the second laser pulse It is possible to equalize the pulse energy of LP2. However, whenever the pulse widths of the first laser pulse LP1 and the second laser pulse LP2 are changed, it is difficult to readjust the diffraction efficiency.

When the pulse width is changed, it is preferable to maintain a state in which the pulse energy of the first laser pulse LP1 and the pulse energy of the second laser pulse LP2 are approximately equal without readjusting the diffraction efficiency.

In the embodiment shown in Fig. 3A, when changing the pulse widths of the first laser pulse LP1 and the second laser pulse LP2, both the rising time and the falling time of the laser pulse are shifted in opposite directions. For this reason, the difference between the rate of change of the pulse energy of the first laser pulse LP1 and the rate of change of the pulse energy of the second laser pulse LP2 when the pulse width is changed becomes smaller than that of the comparative example. As a result, the deviation of the machining quality between the first machining path MP1 and the second machining path MP2 can be reduced.

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

4 is a diagram showing waveforms of the first laser pulses LP1 and the second laser pulses LP2, and the waveforms of the original laser pulses LO, which are cut using the laser pulse cutting apparatus according to the modified example. In this modified example, the first reference time point tr1 and the 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 rising time t0 of the original laser pulse LO to the first reference point tr1 and the second reference point tr2 is constant in all the original laser pulses LO.

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

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

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 extended forward from the first reference point tr1, and the time of the waveform of the first laser pulse LP1 extended backward. The first laser pulse LP1 is cut out so that the width TB becomes the same. Similarly, the second laser pulse LP2 is cut so that the time width TF of the waveform of the second laser pulse LP2 extended forward from the second reference point tr2 is equal to the time width TB of the waveform of the second laser pulse LP2 extended backward pay The time width TF of the first laser pulse LP1 and the time width TF of the second laser pulse LP2 are the same, and the time width TB of the first laser pulse LP1 and the time width TB of the second laser pulse LP2 are the same.

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 extended forward from the first reference point tr1, and the time of the waveform of the first laser pulse LP1 extended backward Shorten the width TB. Similarly, the time width TF of the waveform of the second laser pulse LP2 extended forward from the second reference point tr2 and the time width TB of the waveform of the second laser pulse LP2 extended 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 the same.

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 punching is determined. For example, from the pulse energy required to form the concave portion 65 (FIG. 2B) penetrating the surface copper layer 62 (FIG. 2A), the pulse width of the first laser pulse LP1 and the second laser pulse LP2 is The maximum value can be determined.

Based on the maximum values 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 (FIG. 4) is determined. The pulse width of the original laser pulse LO is, for example, the waiting time width required from the rising time of the original laser pulse LO to the rising time of the first laser pulse LP1, and the second laser pulse LP2 from the falling time of the first laser pulse LP1 The maximum value of the pulse widths of the first laser pulse LP1 and the second laser pulse LP2 is added to the waiting time width required until the rising time and the waiting time width required from the falling time of the second laser pulse LP2 to the falling time of the original laser pulse LO can be decided by

Let 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 as the first reference point tr1, and the second laser pulse The center point on the time axis of the waveform of LP2 may be the second reference point tr2. 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 point of time tr1 to the height of the waveform of the original laser pulse LO at the second reference point of time tr2. Do it.

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 sets the original value based on the maximum value of the input pulse width and the preset waiting time width. A pulse width of the laser pulse LO, a first reference time point tr1, and a second reference time point tr2 are calculated.

In the modified example 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 fixed at the first reference point tr1, 2 The center of the waveform of the laser pulse LP2 on the time axis is fixed at the second reference point tr2. For this reason, even when the pulse width is changed, the light intensity (height of the waveform of the laser pulse) at the central position on the time axis of the waveforms of the first laser pulse LP1 and the second laser pulse LP2 remains unchanged. Accordingly, in the modified example 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 energy of both can be kept substantially the same.

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

5 is a diagram showing waveforms of the first laser pulses LP1 and the second laser pulses LP2, and the waveforms of the original laser pulses LO, which are cut using the laser pulse cutting apparatus according to the present modification.

Also in this modified example, similarly to the modified example shown in Fig. 4, fixed first reference points tr1 and second reference points tr2 are set within the pulse width of the original laser pulse LO.

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

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 point tr1 and the second laser pulse LP2 The relationship between and the second reference time point tr2 satisfies the above condition. That is, H1xPW is equal to the area A1 of the waveform of the first laser pulse LP1, and H2xPW is equal to the area A2 of the waveform of the second laser pulse LP2.

Under the condition that the waveform of the original laser pulse LO at the start of cutting is substantially constant, the height of the waveform at the first reference point tr1 and the second reference point tr2 is substantially constant. For this reason, when the pulse widths of the first laser pulse LP1 and the second laser pulse LP2 are changed in the method according to the present modification, the pulse energies of both after the pulse width change are approximately equal.

In the above embodiments and modified examples, laser pulses are cut from one original laser pulse LO by two processing paths, respectively, but laser pulses may be cut by three or more processing paths. Also in this case, if the pulse width of the laser pulse to be cut out is changed, the timing of rising and falling of the laser pulse to be cut may be shifted in the same manner as in the above embodiment or modified example.

Each of the above-described embodiments is an example, and it goes without saying that partial substitutions or combinations of configurations shown in other embodiments are possible. The same operation and effect by the same configuration of a plurality of embodiments are not sequentially mentioned for each embodiment. In addition, the present invention is not limited to the above-described embodiment. For example, it is apparent to those skilled in the art that various modifications, improvements, combinations, and the like are possible.

10 Laser light source
11 optics
13 Beam Damper
20 Beam Deflector
21 Acousto-Optical Crystals
22 transducer
23 driver
24 Path change terminal
25 cutting terminal
26 1st Diffraction Efficiency Adjustment Knob
27 2nd Diffraction Efficiency Adjustment Knob
30 mirror
31 beam scanner
32 fθ lens
33 Processing object
40 mirror
41 beam scanner
42 fθ lens
43 object to be processed
50 stage
55 control
56 display
57 input device
60 printed board
61 resin layer
62 surface copper layer
63 bottom copper layer
65 recess
LO original laser pulse
LP1 first laser pulse
LP2 2nd laser pulse

Claims (5)

By giving a command to a beam deflector that switches an incident laser beam to either one of a first processing path and a second processing path toward the object in response to a command from the outside, from one original laser pulse incident to the beam deflector , a control device for cutting a first laser pulse toward the first processing path, and a second laser pulse toward the second processing path,
The control device, when changing the pulse widths of the first laser pulse and the second laser pulse, based on the rising time of the original laser pulse, both the rising time and the falling time of the first laser pulse , a laser pulse cutting device for shifting in opposite directions, and shifting both the rising and falling timing of the second laser pulse in opposite directions. According to claim 1,
The control device includes a first reference time point and a second reference time point fixed within the pulse width of the original laser pulse, respectively, included in the pulse width of the first laser pulse and the second laser pulse, and the first reference time point Pulse widths of the first laser pulse and the second laser pulse so that the height of the waveform of the first laser pulse in Changing laser pulse cutting device. 3. The method of claim 2,
The control device is configured such that the time width of the waveform of the first laser pulse extended forward from the first reference point is equal to the time width of the waveform of the first laser pulse extended backward from the second reference point in time Laser pulse cutting for changing the pulse widths of the first laser pulse and the second laser pulse so that the time width of the extended waveform of the second laser pulse is equal to the time width of the waveform of the second laser pulse extended backward Device. 3. The method of claim 2,
The control device is configured such that a value obtained by multiplying a height of a waveform of the first laser pulse at the first reference point by a pulse width of the first laser pulse is equal to an area of a waveform of the first laser pulse, The first laser pulse and A laser pulse cutting device for changing the pulse width of the second laser pulse. A step of cutting the first laser pulse from the first original laser pulse toward the first processing path and cutting the second laser pulse toward the second processing path;
From the second original laser pulse having the same pulse width as the first original laser pulse, the third laser pulse is cut toward the first processing path, and the fourth laser pulse is cut toward the second processing path. have fairness,
When the waveform of the second primary laser pulse is superimposed on the waveform of the first primary laser pulse, the rising and falling of the waveform of the third laser pulse respectively reverse the rising and falling of the waveform of the first laser pulse. The laser pulse cutting method is located at a position shifted in the direction, and the rising and falling of the waveform of the fourth laser pulse are located at a position in which the rising and falling of the waveform of the second laser pulse are shifted in opposite directions, respectively.

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