JP2002011584A - Multi-axis laser machining device and method of laser machining - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively utilize a pulse laser beam emitted from a laser beam source. SOLUTION: Plural pulses arranged on the time axis of the pulse laser beam 2 emitted from the laser beam source 1 are so distributed that each pulse is propagated along either of a first optical axis or a second optical axis by a distributing optical system 10 driven on the basis of an externally given control signal. A first scanning optical system 17 guides a pulse laser beam pl1 propagating along the first optical axis upon a work 51 to be machined, and the point irradiated with the pulse laser beam pl1 is moved. A second scanning optical system 18 guides a pulse laser beam pl2 propagating along the second optical axis upon the work to be machined, and the point irradiated with the pulse laser beam pl2 is moved. While the work 53 to be machined is irradiated with the pulse laser beam through either one of optical scanning systems 17 and 18, the position irradiated with the laser beam is moved by driving the other optical scanning system 18 or 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-axis laser processing apparatus and a laser processing method, and more particularly to a multi-axis laser processing apparatus and a laser processing method for processing by moving a laser irradiation position within a certain range on an object to be processed. About.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Application Publication No. 10-58178 discloses a laser processing apparatus in which each optical axis of a plurality of laser beams is swung by a galvano scanner and a hole is formed at a desired position on a printed wiring board. . JP-A-10-58178
In the laser processing apparatus described in the publication, a pulse laser beam emitted from a laser oscillator is split into two beams by two reflecting mirrors arranged so as to be orthogonal to each other. The optical axis of each of the split beams is oscillated by a galvano scanner, and is converged on an object to be processed by an fθ lens. By condensing the beam at a desired position using a galvano scanner and an fθ lens, a hole can be formed at a desired position.

[0003]

The pulse repetition frequency of a pulse laser beam used for laser processing is 20 kHz.
When z and the output are 2.5 W, a hole having a depth of 40 μm can be formed in the resin substrate with about 40 pulses. At this time, the time required for making one hole is 2 ms. After making one hole, the time required to operate the galvano scanner and move the irradiation position of the laser beam to the position of the next hole is, for example, about 1 ms. Laser pulses emitted during the time the galvano scanner is operating are not used for drilling.

An object of the present invention is to provide a laser processing apparatus and a processing method that can effectively use a pulse laser beam emitted from a laser light source.

[0005]

According to one aspect of the present invention, a laser light source for emitting a pulsed laser beam, and a plurality of pulses of the pulsed laser beam emitted from the laser light source, which are arranged on a time axis, are: A distributing optical system for distributing each pulse so as to propagate along one of the first optical axis and the second optical axis based on an externally applied control signal; and the first optical axis While guiding the pulsed laser beam propagating along the workpiece,
A first scanning optical system that moves an irradiation position of a pulsed laser beam within a certain region on a processing target by being driven based on a signal given from outside;
The pulsed laser beam propagating along the optical axis of the laser beam is guided onto the object to be processed, and is driven based on an externally applied signal. A second scanning optical system for moving a position, and driving the second scanning optical system during the period in which the pulsed laser beam is irradiated onto the workpiece through the first scanning optical system. Is moved, and during the period in which the pulse beam is irradiated onto the workpiece through the second scanning optical system, the first scanning optical system is driven to change the irradiation position of the beam. There is provided a multi-axis laser processing apparatus having a moving means and a control means.

According to another aspect of the present invention, a pulsed laser beam emitted from a laser light source is incident on a first scanning optical system, and the pulsed laser beam is projected onto a workpiece through the first scanning optical system. Irradiating a pulse laser beam through the second scanning optical system during a period in which a pulse laser beam is radiated onto the processing object through the first scanning optical system. Controlling the second scanning optical system so that the position on the object moves; and causing the pulsed laser beam emitted from the laser light source to enter the second scanning optical system, Irradiating the pulsed laser beam to processing,
During the period in which the pulse laser beam is irradiated on the object through the second scanning optical system, the position on the object irradiated by the pulse laser beam passing through the first scanning optical system moves. Controlling the first scanning optical system.

[0007] While one scanning optical system is being controlled, a pulsed laser beam is irradiated onto the workpiece through the other scanning optical system. Therefore, the pulse laser beam emitted from the laser light source can be effectively used.

[0008]

FIG. 1A is a schematic view of a laser processing apparatus according to an embodiment of the present invention. The laser light source 1 is
A pulse laser beam 2 is emitted. The laser light source 1 includes, for example, an Nd: YAG laser oscillator and a nonlinear optical element. The pulse laser beam 2 is, for example, N
d: Third harmonic (wavelength: 355 nm) of the YAG laser.

The pulse laser beam 2 is incident on the distribution optical system 10. The distribution optical system 10 includes the half-wave plate 1
1. Electro-optical element 12 showing Pockels effect, polarizing plate 1
3 is included. The half-wave plate 11 is used for the laser light source 1.
Is converted into linearly polarized light such that it becomes a P wave with respect to the polarizing plate 13. This P wave enters the electro-optical element 12.

[0010] electro-optical element 12 based on a control signal sig ₀ sent from the control unit 40, pivoting the polarization axis of the pulsed laser beam. When the voltage is not applied to the electro-optical element 12, the incident P-wave is emitted as it is. When the voltage is applied to the electro-optical element 12, the electro-optical element 12 rotates the polarization plane of the P wave by 90 degrees. Thereby, the pulse laser beam emitted from the electro-optical element 12 becomes an S wave with respect to the polarizing plate 13.

The polarizing plate 13 transmits the P wave as it is,
Reflects S wave. The P wave transmitted through the polarizing plate 13 has an optical axis 2
It becomes a pulse laser beam pl ₁ propagating along 0.
The S wave reflected by the polarizing plate 13 becomes a pulse laser beam pl ₂ propagating along another optical axis 30. The pulse laser beam pl ₁ propagating along the optical axis 20 is incident on the first scanning optical system 17, and the pulse laser beam pl ₂ propagating along the other optical axis 30 is transmitted through the second scanning optical system 18. Incident on.

The pulse train incident on the first scanning optical system 17
The beam pl₁Are reflected by the folding mirrors 21 and 22.
And enters the half mirror 23. Half mirror 23
Converts the incident pulsed laser beam into
The laser beam is split into two laser beams having lugi. Half Mi
The pulsed laser beam reflected by the
The light enters the canner 25. The light transmitted through the half mirror 23
The loose laser beam is reflected by the return mirror 24,
To the galvano scanner 26. Galvano scanner
25 and 26 are respectively transmitted from the control device 40
Drive signal sig ₁₁And sig₁₂Driven by

The laser beams passing through the galvano scanners 25 and 26 are condensed on the surface of a resin substrate 51 by fθ lenses 27 and 28, respectively. Resin substrate 51
Are fixed on the substrate mounting table 50. Resin substrate 5
1, a hole is formed at the position where the pulsed laser beam is focused.

The pulse laser beam pl ₂ incident on the second scanning optical system 18 is reflected by the return mirror 31 and is incident on the half mirror 32. The half mirror 32 divides the incident pulse laser beam into two laser beams having mutually equal energies. Half mirror 32
The pulsed laser beam reflected by the
4 is incident. The pulse laser beam transmitted through the half mirror 32 is reflected by the return mirror 33 and enters another galvano scanner 35. The galvano scanners 36 and 37 are driven by drive signals sig ₂₁ and sig ₂₂ transmitted from the control device 40, respectively.

The laser beams passing through the galvano scanners 34 and 35 are focused on the surface of the resin substrate 53 by fθ lenses 36 and 37, respectively. Resin substrate 53
Are fixed on the substrate mounting table 52. A hole is formed at the position where the pulsed laser beam is focused.

Next, with reference to FIG.
The control method for the zero and galvano scanners 34, 35, 25, and 24 will be described.

FIG. 2 shows a control signal sig.₀, Drive signal si
g₁₁, Sig₁₂, Sig_{twenty one}, Sig_{Two Two}And pulse train
The beam pl₁, Pl_Two3 shows a timing chart. System
Control signal sig₀, The electro-optical element 12 has no voltage
The first period T1 in the added state is shown in FIG.
Pulsed laser beam passing through the electro-optical element 12
Because it is a P-wave, a pulsed laser beam along the optical axis 20
pl₁Is output, and the pulse laser beam along the optical axis 30 is output.
Mu pl_TwoIs not output. Therefore, the first scanning optical system
Pulses passed through 17 galvanometer scanners 25 and 26
Drilling is performed by the laser beam.

[0018] During the first period T1, the control unit 40, to the galvanometer scanner 34 and 35 of the second scanning optical system 18, respectively and transmits the driving signal sig ₂₁ and sig _22. As a result, the galvanometer scanners 34 and 35
Control is performed so that the pulse laser beam is focused on a desired position on the resin substrate 51.

[0019] In the second period T2 after the first period T1, the control signal sig _0, the electro-optical element 12 is a voltage applied state. Therefore, in the second period T2, the pulse laser beam pl ₁ is not outputted, the pulse laser beam pl ₂ is output. During the preceding first period T1,
Since the galvano scanners 34 and 35 are driven and the point where the pulse laser beam is to be focused is adjusted, it is possible to make a hole at a desired position during the second period T2.

Further, during the second period T2, the control device 4
0 indicates drive signals sig ₁₁ and sig to the galvano scanners 27 and 28 of the first scanning optical system 17, respectively.
Send ₁₂ As a result, the galvano scanners 27 and 28 are controlled so that the pulse laser beam is focused on a desired position on the resin substrate 51.

By alternately repeating the first period T1 and the second period T2, holes can be formed at a plurality of desired positions on the resin substrate 51.

In the above embodiment, during the second period T2 during which the galvano scanners 25 and 26 of the first scanning optical system 17 are driven, holes are drilled by the pulse laser beam passing through the second scanning optical system 18. Is performed. Further, during the first period T1 during which the galvano scanners 34 and 35 of the second scanning optical system 18 are driven, drilling is performed by the pulsed laser beam that has passed through the first scanning optical system 17. For this reason, all the pulses of the pulsed laser beam emitted from the laser light source 1 are effectively used for drilling.

Consider a case where a pulse laser beam having a pulse repetition frequency of 20 kHz and a power of 2.5 W is used to make a hole having a depth of 40 μm in a resin substrate. By irradiating one place on the resin substrate with 40 pulses, a depth of 40 μm
Can be drilled. That is, the processing time for one hole is 2 ms. Approximately 1 m to drive the galvano scanner and move the irradiation point of the pulsed laser beam
s is required. For this reason, when a plurality of holes are formed using only one scanning optical system, the time required for forming one hole is 3 ms including the driving time of the galvano scanner.

In the above embodiment, the first period T1 and the second period T2 are set to 2 ms. At this time, one hole can be formed in the first period T1, and one hole can be formed in the second period T2. That is, two holes can be formed in 4 ms. The processing time required for each piece is 2 ms, which indicates that the drive time of the galvano scanner can be ignored.

In the above embodiment, the sorting optical system 10
A plurality of pulses arranged on the time axis are distributed to two optical axes. This distribution does not change the energy per pulse. Further, the half mirrors 23 and 32
Splits one pulse into two optical axes. By this optical axis division, the energy per pulse is reduced to about half.

The resin substrate can be perforated even if the energy per pulse is low. For this reason, even if the pulse laser beam is split by the half mirror, it is possible to secure the energy required for drilling. Further, when making holes in copper foil or the like, the energy per pulse must be increased. When the energy required for drilling cannot be secured by splitting the laser beam with the half mirror, the splitting of the beam by the half mirror may be omitted.

Further, in the above embodiment, the Nd: YAG laser is used as the laser light source, and the third harmonic is used for the processing. However, another laser light source that can make a hole in the object to be processed may be used. For example, Nd: YAG laser or N
d: A fundamental wave of a YLF laser or a harmonic thereof may be used, or a carbon dioxide laser may be used.

The present invention has been described in connection with the preferred embodiments.
The present invention is not limited to these. For example, it will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

[0029]

As described above, according to the present invention,
Using at least two scanning optical systems, processing is performed with a pulsed laser beam that has passed through the other scanning optical system while the laser irradiation position of one scanning optical system is being moved. For this reason, the pulse laser beam emitted during the period in which the laser irradiation position by one of the scanning optical systems is moved can also be used effectively. When processing is performed using one scanning optical system, a pulse laser beam that has not been used can be used, so that the throughput can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic view of a laser processing apparatus according to an embodiment.

FIG. 2 is a timing chart of a pulse laser beam and various control signals when performing laser processing using the laser processing apparatus according to the embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 laser light source 2 pulse laser beam 10 sorting optical system 11 half-wave plate 12 electro-optical element 13 polarizing plate 17 first scanning optical system 18 second scanning optical system 20, 30 optical axis 21, 22, 24, 31, 33 Folding mirror 23, 32 Half mirror 25, 26, 34, 35 Galvano scanner 27, 28, 36, 37 fθ lens 40 Controller 50, 52 Substrate holder 51, 53 Resin substrate

Claims (3)

[Claims] 1. A laser light source for emitting a pulse laser beam, and a pulse laser beam emitted from the laser light source,
The plurality of pulses arranged on the time axis are converted into a first optical axis and a second pulse based on a control signal given from the outside.
A distributing optical system for distributing so as to propagate along any one of the optical axes, and a pulse laser beam propagating along the first optical axis, which is directed onto a processing target and given from outside. A first scanning optical system that moves the irradiation position of the pulsed laser beam within a certain region on the object to be processed by being driven based on a signal to be processed; and a pulse that propagates along the second optical axis. A second scanning optical system that guides a laser beam onto a processing target and moves the irradiation position of the pulse laser beam within a certain region on the processing target by being driven based on an externally applied signal. And the pulse laser beam is irradiated on the processing target object through the first scanning optical system, and drives the second scanning optical system to move the irradiation position of the beam. Control means for driving the first scanning optical system to move the irradiation position of the beam during a period in which the pulse beam is being irradiated onto the workpiece through the second scanning optical system; and Multi-axis laser processing device having 2. The first scanning optical system divides a pulse laser beam propagating along the first optical axis into a plurality of beams, and moves each irradiation position of the divided pulse laser beams. 2. The method according to claim 1, wherein the second scanning optical system divides the pulse laser beam propagating along the second optical axis into a plurality of beams, and moves each irradiation position of the divided pulse laser beams. The multi-axis laser processing apparatus according to the above. 3. A process in which a pulsed laser beam emitted from a laser light source is incident on a first scanning optical system, and the object is irradiated with the pulsed laser beam through the first scanning optical system for processing. And a position on the object to be irradiated with the pulsed laser beam passing through the second scanning optical system moves while the pulsed laser beam is being irradiated onto the object through the first scanning optical system. Controlling the second scanning optical system as described above, a pulsed laser beam emitted from the laser light source,
Irradiating the pulsed laser beam on the object to be processed by irradiating the pulsed laser beam on the object to be processed, Controlling the first scanning optical system so that the position on the processing target irradiated with the pulse laser beam passing through the first scanning optical system moves during a certain period.