JP2008049383A - Beam irradiation method and beam irradiation apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a beam irradiation method having a high time efficiency. <P>SOLUTION: This beam irradiation apparatus comprises a laser beam source for emitting a laser beam, a sub-deflecting device, which can vary the deflection angle, for deflecting the laser beam emitted from the laser beam source, and a main deflecting device, which can vary the deflection angle and is disposed at a position where the laser beam deflected by the sub-deflecting device is incident. The maximum deflecting angle of the main deflecting device is larger than the maximum deflecting angle of the sub-deflecting device, and the response speed for deflecting the laser beam is lower than that of the sub-deflecting device. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a beam irradiation method for performing processing by irradiating a laser beam, and a beam irradiation apparatus.

  The multilayer printed circuit board is a printed circuit board having a multilayered inside, and is used when a large-scale electronic circuit is mounted in a small area.

  FIG. 4 is a schematic cross-sectional view of a multilayer printed board. The multilayer printed circuit board has a structure in which conductive layers 21 and insulating layers 22 are alternately stacked. Conductive layer 21 is formed of, for example, copper, and insulating layer 22 is formed of, for example, an epoxy resin or a polyimide resin.

  Each conductive layer 21 is insulated from each other by an insulating layer 22, and an electronic circuit is independently formed in each layer. When it is necessary to electrically connect electronic circuits of different layers, a method is used in which a via hole 23 that penetrates the insulating layer 22 is provided and the inner wall is plated to perform electrical connection. There may be hundreds to tens of thousands of via holes 23 formed on one printed circuit board.

  The formation of the via hole 23 has been conventionally performed using a metal drill, but in recent years, with the improvement of the substrate mounting density, laser processing that can form a via hole 23 having a smaller diameter has been used (for example, Patent Document 1). A processing apparatus that performs such laser processing is called a laser drill apparatus.

  FIG. 5 is a schematic view showing a laser drill apparatus.

A laser light source 30, for example, a carbon dioxide laser, emits a pulse laser beam 31 with a frequency of 2 kHz and a pulse width of 60 μsec, for example. As the pulse laser beam 31, a fundamental wave or second to fourth harmonics of a YAG laser or YLF laser may be used.
The laser beam 31 is incident on a galvano scanner 35 through an optical system 32 including a lens 33 and a mask 34 having a transmission region that shapes the cross-sectional shape of the beam. The galvano scanner 35 includes, for example, a pair of swingable mirrors, and deflects and emits the incident laser beam 31. It is also possible to change the deflection angle. The galvano scanner 35 will be described in detail with reference to the following diagram.

  On the XY stage 37, a holding surface is provided, and the printed circuit board 20 that is an object to be processed is placed on the holding surface. The XY stage 37 has a vacuum chuck function, and the printed circuit board 20 can be fixed on the XY stage 37 through exhaust by the exhaust pump 41. The XY stage 37 can move the printed circuit board 20 in the in-plane direction (XY direction) of the holding surface.

  The laser beam 31 emitted from the galvano scanner 35 enters the printed board 20 perpendicularly by the action of the fθ lens 36.

  The fθ lens 36 can image the cross-sectional shape of the laser beam at the position of the transmission region of the mask 34 on the workpiece. The printed circuit board 20 is placed on the XY stage 37 so that an image of the cross-sectional shape of the laser beam at the position of the transmission region of the mask 34 is formed on the surface thereof.

  The controller 38 controls the operations of the galvano scanner 35 and the XY stage 37. A control signal transmitted from the controller 38 to the galvano scanner 35 and the XY stage 37 is generated based on via hole formation position data or the like given in advance from the operation device 39 to the controller 38.

  FIG. 6 is a schematic perspective view showing the galvano scanner 35.

  The galvano scanner 35 includes a first galvano scanner 51 and a second galvano scanner 52. The first galvano scanner 51 and the second galvano scanner 52 are configured to include galvano motors 51a and 52a, shafts 51b and 52b, and galvano mirrors 51c and 52c, respectively.

  The galvano motors 51a and 52a generate rotational torque for rotating (swinging) the galvano mirrors 51c and 52c based on the control signal transmitted from the controller 38. The rotational torque is transmitted to the galvanometer mirrors 51c and 52c via the shafts 51b and 52b, and the galvanometer mirrors 51c and 52c rotate (swing) around the shafts 51b and 52b.

  As shown in the figure, when the XYZ rectangular coordinate system is defined, for example, the galvanometer mirror 51c of the first galvano scanner 51 rotates (oscillates) around the shaft 51b arranged in parallel to the Z axis, and the second galvano scanner The galvano mirror 52c 52 rotates (swings) around the shaft 52b arranged in parallel to the Y axis.

  For example, the laser beam 31 enters the first galvano scanner 51 from a direction parallel to the Y axis. The laser beam 31 is reflected by the galvanometer mirror 51 c, travels in a plane parallel to the XY plane, and enters the galvanometer mirror 52 c of the second galvanometer scanner 52. Thereafter, the light is reflected by the galvanometer mirror 52c and enters the object to be processed through the fθ lens 36.

  FIG. 7 is a schematic plan view showing a region to be processed (via hole forming region) on the printed circuit board. With reference to this figure, the via-hole formation method by a laser drill apparatus is demonstrated.

  The range (scanning range) in which the via hole can be precisely positioned by the galvano scanner and the fθ lens is limited, and is, for example, a rectangular region with a side of about several tens of mm. For this reason, when forming a via hole in a wider processing region, it is usual to use both beam scanning by a galvano scanner and feeding operation of an XY stage.

  As shown in FIG. 7, the region to be processed (via hole forming region) on the printed board is a square region having a side of 500 mm, for example. In this region, for example, 100,000 via holes are formed.

The range in which beam scanning is possible only by the operation of the galvano scanner is, for example, a square region (section) having a side of 50 mm. Therefore, the region to be processed (via hole forming region) is divided into square regions each having a side of 50 mm, and processing is performed for each of the divided regions. In this figure, a square region having a side of 50 mm divided from a region to be processed (via hole formation region) is shown with reference numerals S ₁ , S ₂ , S ₃ ,. For example, 1000 via holes are formed in each of the regions S ₁ , S ₂ , S ₃ ,.

In the beam scanning by the galvanometer scanner to form a via hole in a region S _1. For example, one shot of a pulse laser beam is irradiated to form one via hole. When the formation of one hole is finished, to position the galvano mirror, to another location in the region S _1, to form another hole. During the positioning period of the galvanometer mirror, the laser oscillation is stopped. Repeating this to complete the via hole machining area S _1.

Subsequently, the printed board is moved on the XY stage so that the next section (region S ₂ ) of the printed board is within the scanning range of the galvano scanner. Thereafter, the beam scanning by the galvanometer scanner, to form a 1,000 holes in a region _{S 2.} Next, the printed circuit board is moved by an XY stage so that the next section (area S ₃ ) of the printed circuit board is within the scanning range of the galvano scanner, and a via hole is formed in the area S ₃ by beam scanning by the galvano scanner. By repeating this, via hole formation processing is performed on all sections of the printed circuit board.

The series of operations described above are executed by issuing a control signal from the controller based on the via hole formation position data input in advance from the operating device. Positioning of a pair of galvano mirrors, the laser irradiation, the positioning of the XY stage after completion of processing of a region S _n, is repeated.

  In the above-described via hole forming process, after completion of one via hole forming process by laser beam irradiation of four shots, rotation of the galvanometer mirror is started to align with the next target position. The laser beam irradiation is started after the pair of galvanometer mirrors stops at the target position. That is, the laser oscillation is stopped during the positioning period of the galvano scanner (galvano mirror). Note that laser oscillation is often stopped during positioning of the printed circuit board by the XY stage.

  High throughput of via hole formation processing by a laser drill device can be realized by, for example, increasing the laser pulse rate, shortening the positioning time of the pair of galvanometer mirrors, and the positioning time of the XY stage. The positioning time here is the time from the start of movement to the alignment with a predetermined target position.

  All of the above three methods for increasing the throughput are limited by the mechanical and electrical characteristics of the laser drill apparatus, so there is a limit to increasing the throughput of the conventional laser drill apparatus. Further, due to the effect of the fθ lens described above, the moving distance of the laser beam irradiation position is proportional to the deflection angle of the galvanometer mirror, so that the positioning time becomes longer as the moving distance increases.

  Therefore, when a plurality of via holes are continuously formed, a method of rearranging via hole position data and reconnecting them with a shorter path has been often employed in order to shorten the total processing time.

  Of the three elements related to the processing time of via hole formation processing by the laser drill device, the oscillation frequency of the laser oscillator, the positioning time of the pair of galvanometer mirrors, and the positioning time of the XY stage, the most effective for shortening the processing time There is a positioning time of a pair of galvanometer mirrors.

  The time required for one movement of the printed board by the XY stage is, for example, 0.5 seconds or less. However, since the number of times of driving the XY stage is extremely smaller than the number of times of irradiation of the laser beam and the number of times of driving the galvano mirror, shortening of the positioning time of the XY stage does not greatly contribute to speeding up the processing.

  The oscillation frequency of a carbon dioxide laser oscillator that is suitably used when processing a polyimide resin or an epoxy resin is, for example, a maximum of 100 kHz by an RF excitation method. In contrast, the drive frequency of the galvanometer mirror in the galvano scanner is 2 kHz, for example, and the maximum drive frequency is 3 kHz, for example. These are much smaller than the oscillation frequency of the laser oscillator.

  Therefore, in the laser drill apparatus, it has been considered that an improvement in the driving speed of the galvanometer mirror is important for achieving a high throughput.

  As seen in recent miniaturization of cellular phones, it is desired to reduce the diameter and increase the density of via holes on a printed wiring board. In order to reduce the diameter of the via hole, a method of increasing the beam diameter of the laser beam incident on the galvanometer mirror or shortening the focal length of the fθ lens is employed.

  However, if a large mirror is used with a large beam diameter, the driving speed of the galvanometer mirror must be reduced, which requires processing time. On the other hand, the focal length of the fθ lens is set while ensuring the same processing range. If the length is shortened, it is necessary to increase the rotation angle of the galvanometer mirror, which increases the processing time and makes it difficult to increase the density.

JP 2002-35975 A

  An object of the present invention is to provide a beam irradiation method with high time efficiency.

  Moreover, it is providing the beam irradiation apparatus which can implement the beam irradiation method with high time efficiency.

According to one aspect of the present invention, a laser beam is deflected by a sub deflector, the laser beam deflected by the sub deflector is further deflected by a main deflector, and the laser beam is deflected by the main deflector. (A) In a state in which the deflection angle by the main deflector is fixed, the deflection angle by the sub-deflector is changed, and a laser beam is applied onto the workpiece. And (b) a step of changing a deflection angle by the main deflector, and (c) a step of repeatedly executing the step a and the step b, and the main deflector. A beam irradiation method is provided in which the maximum deflection angle is greater than the maximum deflection angle of the sub-deflector and the response speed of the main deflector is slower than that of the sub-deflector.
According to another aspect of the present invention, the laser beam is deflected by the sub deflector, and the laser beam deflected by the sub deflector is further deflected by the main deflector and deflected by the main deflector. The laser beam is incident on the object to be processed in which the first processing region and the second processing region are defined, and (a) in a state where the deflection angle by the main deflector is fixed, Changing the deflection angle by the sub-deflector and making the laser beam incident on the first processing region to perform drilling; and (b) so that the laser beam is incident on the second processing region. A step of changing a deflection angle by the main deflector; and (c) changing a deflection angle by the sub-deflector in a state where the deflection angle by the main deflector is fixed, and applying laser to the second processing region. Drilling with a beam incident A beam irradiation method in which a maximum deflection angle of the main deflector is larger than a maximum deflection angle of the sub deflector and a response speed of the main deflector is slower than that of the sub deflector. Provided.

  According to another aspect of the present invention, a laser light source that emits a laser beam, a sub-deflector with a variable deflection angle that deflects the laser beam emitted from the laser light source, and the sub-deflector deflected by the sub-deflector. A main deflector having a variable deflection angle disposed at a position where a laser beam is incident, wherein the maximum deflection angle is larger than the maximum deflection angle of the sub-deflector and the response speed for deflecting the laser beam is the sub-deflector. A beam irradiation device is provided having a main deflector slower than that of the deflector.

  According to the present invention, a time-effective beam irradiation method can be provided.

  In addition, it is possible to provide a beam irradiation apparatus capable of performing a time-effective beam irradiation method.

  FIG. 1 is a schematic diagram illustrating a laser processing apparatus according to an embodiment.

  The laser drill device shown in FIG. 5 includes an X-direction scanning AOD (Acousto-Optic Deflector) 42 and a Y-direction scanning AOD 43 controlled by the controller 38 immediately before the galvano scanner 35. It differs in that it is subscribed. The X-direction scanning AOD 42 and the Y-direction scanning AOD 43 have the same basic configuration, and are arranged in series orthogonal to each other.

  Each of the X-direction scanning AOD 42 and the Y-direction scanning AOD 43 can emit the incident laser beam 31 by deflecting it along one direction (direction orthogonal to each other). Each deflection angle can be changed by changing the wavelength of the ultrasonic wave applied to the X-direction scanning AOD 42 and the Y-direction scanning AOD 43, respectively. For this reason, the laser beam 31 incident on the printed circuit board 20 can be scanned in two orthogonal directions (for example, the X direction and the Y direction in FIG. 3 referred later).

  In addition to controlling the galvano scanner 35 and the XY stage 37, the controller 38 controls the wavelength of the ultrasonic wave loaded on the X-direction scanning AOD 42 and the Y-direction scanning AOD 43, the timing of the load, and the like.

  FIG. 2 is a schematic diagram showing an AOD.

  The AOD is formed using BBO, KTP, LiTaO crystal, Ge single crystal, and the like, and includes, for example, each part of the ultrasonic medium 44, the transducer 45, and the ultrasonic absorber 46. AOD uses the Bragg diffraction phenomenon in the ultrasonic medium 44 and changes the frequency (wavelength) of the ultrasonic wave loaded on the AOD, thereby changing the deflection angle of the laser beam.

  The maximum deflection angle of AOD is smaller than the maximum deflection angle of the galvano scanner. However, the response speed at which the AOD deflects the laser beam is faster than the response speed at which the galvano scanner deflects the laser beam.

  The ultrasonic waves are generated by an oscillator by a deflection signal (control signal) from the controller 38, for example, and transmitted to the AOD via an amplifier.

When the laser beam 31 having the wavelength λ is incident on the AOD in a state where an ultrasonic wave having the frequency f ₀ is loaded on the AOD, the laser beam 31 is deflected in the direction of the deflection angle θ and emits the AOD. When the wavelength of the ultrasonic wave is Λ, the deflection angle θ is expressed by the following equation (1).

θ = sin ⁻¹ (λ / (2 * Λ)) ≈λ / (2 * Λ) (1)
Here, if the propagation velocity of the ultrasonic wave in the AOD is v,
Λ = v / f ₀ (2)
Therefore, the expression (2) is substituted into the expression (1) to obtain the following expression (3).

θ≈ (λ * f ₀ ) / (2 * v) (3)
Therefore, when the frequency of the ultrasonic wave loaded on the AOD is changed by Δf, the deflection angle variation θ _d can be expressed by the following equation (4).

θ _d ≈ (λ * Δf) / v (4)
As described above, the AOD can change the deflection angle of the emitted laser beam by changing the frequency (wavelength) of the applied ultrasonic wave.

In the laser processing apparatus shown in FIG. 1, the X-direction scanning AOD 42 or the Y-direction scanning AOD 43 is loaded with ultrasonic waves having a frequency of about 50 MHz, for example, and the incident laser beam 31 is deflected and emitted in one direction. To do. Here, the maximum value of the deflection angle variation θ _d is, for example, about 4 °.

  On the other hand, the swing angle of a normal galvanometer mirror is about 40 °, and the range in which the AOD can be scanned is about 1/10 of the galvanometer mirror. Accordingly, instead of moving the galvanometer mirror by dividing the area scanned by the galvanometer mirror alone, it is possible to perform interpolation such that the AOD is scanned and the AOD is scanned with the galvanometer mirror fixed.

FIG. 3 is an enlarged view of a region to be processed (via hole forming region) on the printed board shown in FIG. With reference to this figure, a laser processing (via hole forming processing) method (hereinafter referred to as a laser processing method according to an embodiment) performed using the laser processing apparatus according to the embodiment shown in FIG. 1 will be described. In this laser processing method, each of the areas S ₁ , S ₂ ,... In FIG. 7 (a square area having a side of 50 mm) is divided into square areas (T ₁ , T ₂ ,...) Having a side of 5 mm. , Regions T ₁ , T ₂ ,. The information regarding the definition of each region of S ₁ , S ₂ ,..., T ₁ , T ₂ ,.

First, the processing of the area _{T 1.} Perform positioning of the XY stage and galvanometer scanner (galvanometer mirror) (the deflection angle by the galvano scanner, for example, it was fixed in the center of the area T ₁₎ after, X-direction scanning AOD, and, in the Y-direction scanning AOD Ultra A pulsed laser beam is emitted while applying a sound wave. A four-shot pulse laser beam is incident on the via hole forming position, and one via hole is formed.
The frequency of the ultrasonic wave loaded on the X-direction scanning AOD and the Y-direction scanning AOD is changed (increased or decreased) without stopping the laser oscillation. The deflection angle of the laser beam emitted from the X-direction scanning AOD and the Y-direction scanning AOD changes, the beam incident position on the printed board also changes, and a via hole is formed at a different position. The movement of the beam incident position in the region T ₁ (T _n ) is performed using the X-direction scanning AOD for the X direction and is performed using the Y-direction scanning AOD for the Y direction. All the via holes (via holes h _{10 to} h ₁₉ ) in the region T ₁ are formed by scanning the laser beam on the printed board.

The formation order of the via holes h _{10 to} h ₁₉ is calculated and determined in advance by a computer so that, for example, prior to processing, the path to be followed according to the formation order is the shortest.
After forming a via hole machining region T ₁ is completed, performs a positioning of the optical scanner (galvano mirror), followed by for example performing processing area T _2. As described above, in the laser processing method according to the embodiment, when processing of the region T _n is finished and processing of the region T _{n + 1} is started, positioning is performed using the galvano scanner (galvano mirror). During the positioning of the galvano scanner (galvano mirror), the laser oscillation is stopped.

Like the machining region T _1, X-direction, and an ultrasonic wave was loaded in the Y-direction scanning AOD, while changing, it emits a pulsed laser beam. By scanning a laser beam on the printed circuit board to form a via hole in the region T _2.

When the via hole formation processing of all the regions T _n in the region S ₁ is completed, the printed circuit board is moved on the XY stage so that the next processed section (region S ₂ ) of the printed circuit board is within the scanning range of the galvano scanner. , the beam scanning using an X-direction and Y-direction scanning AOD, a via hole is formed for each area T _n. In such laser processing method according to an embodiment, for example finished machining area S _n, when the processing area S _{n + 1} is started, positioned using the XY stage is performed.

  In this way, the formation of via holes is completed for the entire region to be processed (via hole forming region) on the printed circuit board.

  The laser processing method according to the embodiment scans the laser beam with an AOD arranged in front of the galvano scanner, thereby reducing the number of times the galvano scanner (galvano mirror) is driven and enabling high-throughput via hole formation processing.

Hereinafter, a time required for via hole formation processing performed using the via hole formation method described with reference to FIG. 7 (hereinafter, processing time according to the conventional method) and a time required for via hole formation processing performed using the laser processing method according to the embodiment will be described. (Hereinafter, processing time according to the method of implementation) is calculated and compared. The processing time is calculated for a square region (for example, S ₁ ) having a side of 50 mm.

  First, the processing time by the conventional method is calculated.

The positioning time (settling time) of the galvano scanner (galvanometer mirror) is T _g (msec), and the cycle time from emitting one laser beam pulse to emitting the next one pulse is Y (msec). When the required number of shots of the pulse laser beam is X and the number of holes (via holes) formed in a square region (for example, S ₁ ) having a side of 50 mm is n, the processing time according to the conventional method is expressed by the following equation (5). expressed.

(T _g + Y * X) * n (5)
Next, the machining time according to the implementation method is calculated.

When processing a square area (for example, T ₁ ) with a side of 5 mm by AOD, the total time required to drive a galvano scanner (galvano mirror) within a square area (for example, S ₁ ) with a side of 50 mm is:
100 * T _g (6)
The total processing time without moving the galvo scanner (galvano mirror) is
Y * X * n (7)
It is represented by

Therefore, the time required to process a square area (for example, S ₁ ) having a side of 50 mm is obtained from the equations (6) and (7):
Y * X * n + 100 * T _g (8)
It becomes.

  Substituting specific numerical values into the equations (5) and (8).

When the driving frequency of the optical scanner (galvanometer mirror) and 2 (kHz), _{T g} is 0.5 (msec). If the oscillation frequency of the laser oscillator is 10 (kHz), Y is 0.1 (msec).

It is assumed that the substrate effective processing region (processed region, via hole forming region) is, for example, a square region having a side of 500 mm, and 100,000 via holes are formed in the region. In this case, 1000 holes (n = 1000) of via holes are formed per square area (for example, S ₁ ) having a side of 50 mm. If the pulse laser necessary to form one via hole is 4 shots (X = 4), at a certain stage position,
The processing time according to the conventional method is expressed by equation (5).
(0.5 + 0.1 * 4) * 1000 = 900 (msec)
It becomes.

Further, the processing time according to the implementation method is expressed by the following equation (8).
(0.1 * 4 * 1000) + 100 * 0.5 = 450 (msec)
It becomes.

  Therefore, when the processing method according to the embodiment is used, the processing time can be reduced to, for example, ½ compared to the processing method according to the conventional example. This shortening effect increases as the oscillation frequency of the laser oscillator increases and the number of holes increases.

  In addition, according to the laser processing method according to the embodiment, the number of laser oscillation stops can be reduced.

  The laser oscillation does not have to be stopped during a period other than the positioning period of the galvano scanner (galvano mirror) and the positioning period of the XY stage.

  As described above, for example, a typical AOD frequency is 50 MHz, and a laser oscillator frequency is 100 kHz. Furthermore, the pulse width of the pulse laser beam used is 60 μsec. Therefore, in the laser processing method according to the embodiment, it is possible to change the AOD frequency and form a plurality of via holes in a state where the laser is continuously oscillated. For this reason, as a reflective effect of reducing the number of times the galvano scanner (galvano mirror) is driven, the number of times laser oscillation is stopped can be reduced. This is desirable for good processing without deteriorating the output stability for each pulse.

  In the laser processing apparatus according to the embodiment, it is preferable that the X-direction and Y-direction scanning AODs are arranged immediately before the galvano scanner. This is because the galvano scanner (galvano mirror) needs to be arranged at the pupil position of the fθ lens. When the beam is deflected with a large deflection angle, if the distance between the AOD and the galvano scanner is large, the galvano scanner This is because the position shift at the (galvano mirror) becomes large.

  As mentioned above, although this invention was demonstrated along the Example, this invention is not limited to these.

For example, EOD (Electro-Optic Deflector) can be used instead of AOD. The EOD is made of, for example, DKDP or LiTaO ₃ , and can deflect the laser beam by utilizing a refractive index change (Pockels effect) due to the electric field of the birefringent crystal. However, there is a demerit that the incident laser beam needs to be linearly polarized light and the deflection sensitivity (ratio of change in deflection angle with respect to change in voltage) is small.

  It will be apparent to those skilled in the art that other various modifications, improvements, combinations, and the like are possible.

  It can be used in general for laser processing and laser processing apparatus. In particular, the present invention is suitably used in a laser processing method and a laser processing apparatus that perform via hole formation processing.

It is the schematic which shows the laser processing apparatus by an Example. It is the schematic which shows AOD. FIG. 8 is an enlarged view of a region to be processed (via hole formation region) on the printed board shown in FIG. 7. It is a schematic sectional drawing of a multilayer printed circuit board. It is the schematic which shows a laser drill apparatus. 3 is a schematic perspective view showing a galvano scanner 35. FIG. It is a schematic plan view which shows the to-be-processed area | region (via hole formation area) on a printed circuit board.

Explanation of symbols

20 Printed circuit board 21 Conductive layer 22 Insulating layer 23 Via hole 30 Laser light source 31 Laser beam 32 Optical system 33 Lens 34 Mask 35 Galvano scanner 36 fθ lens 37 XY stage 38 Controller 39 Operating device 41 Exhaust pump 42 AOD for X direction scanning
43 AOD for Y-direction scanning
44 Ultrasonic medium 45 Transducer 46 Ultrasonic absorber 51 First galvano scanner 52 Second galvano scanner 51a, 52a Galvano motor 51b, 52b Shaft 51c, 52c Galvano mirror

Claims (4)

Beam irradiation in which a laser beam is deflected by a sub deflector, the laser beam deflected by the sub deflector is further deflected by a main deflector, and the laser beam deflected by the main deflector is incident on a workpiece. A method,
(A) changing the deflection angle by the sub-deflector in a state where the deflection angle by the main deflector is fixed, and performing processing by making a laser beam incident on the workpiece;
(B) changing the deflection angle by the main deflector;
(C) repetitively executing the steps a and b, wherein the maximum deflection angle of the main deflector is larger than the maximum deflection angle of the sub-deflector and the response speed of the main deflector However, the beam irradiation method is slower than that of the sub deflector. The laser beam is deflected by the sub-deflector, the laser beam deflected by the sub-deflector is further deflected by the main deflector, and the laser beam deflected by the main deflector is converted into the first processing region and the first processing region. A beam irradiation method in which an object to be processed in which two processing regions are defined is incident,
(A) performing a drilling process by changing a deflection angle by the sub-deflector in a state where a deflection angle by the main deflector is fixed and making a laser beam incident on the first processing region;
(B) changing a deflection angle by the main deflector so that a laser beam is incident on the second processing region;
And (c) performing a drilling process by changing the deflection angle by the sub-deflector while the deflection angle by the main deflector is fixed and causing the laser beam to enter the second processing region. A beam irradiation method in which the maximum deflection angle of the main deflector is larger than the maximum deflection angle of the sub deflector and the response speed of the main deflector is slower than that of the sub deflector. A laser light source for emitting a laser beam;
A sub-deflector with a variable deflection angle for deflecting the laser beam emitted from the laser light source;
A main deflector having a variable deflection angle disposed at a position where the laser beam deflected by the sub deflector is incident, the maximum deflection angle being larger than the maximum deflection angle of the sub deflector, and the laser beam being A beam irradiation apparatus comprising: a main deflector whose response speed to deflect is slower than that of the sub-deflector. The beam irradiation apparatus according to claim 3, wherein the sub deflector is an acousto-optic deflector.

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