JP2002176006A - Apparatus and method for laser processing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for laser processing capable of simply controlling a pulse shape of a laser beam and enhancing stability of a laser output. SOLUTION: A trigger signal is output from a control computer 60 to respective solid state laser units 21 to 24 at suitable timing, and laser beams L11 to L22 are emitted from the respective units 21 to 24 at a suitable time difference and polarizing surfaces. The respective beams L11 to L22 are coupled by a coupling optical system 30 to become two sets of the beams L1 and L2 slightly separately advanced in parallel. Both the beams L1 and L2 are enlarged in a beam diameter as retaining as a parallel luminous flux via a telescopic optical system 40, and spatially superposed. The beams L1 and L2 fed through the system 40 are disassembled into secondary light sources of 6×6 by a homogenizer 50, and superposed on a processing surface IS to be incident.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a laser processing apparatus and method using a pulse laser, and more particularly to a laser processing apparatus and method suitable for annealing a semiconductor thin film.

[0002]

2. Description of the Related Art In semiconductor processes such as annealing, lithography, and doping, ultraviolet light is mainly used as useful from the viewpoint of photon energy and miniaturization.

As a conventional laser processing apparatus used in a semiconductor process, a laser annealing apparatus for converting amorphous Si to polycrystalline Si using, for example, an excimer laser is known. In such a laser annealing apparatus, a pulse laser from a high-power excimer laser is once divided by a homogenizing optical system, and is irradiated as a uniform beam of the same size on a processing surface in a superimposed manner.

[0004]

In the above-described laser processing apparatus, the pulse waveform of the laser beam can hardly be controlled, so that the degree of freedom for the process is reduced. Further, due to the limit of the performance of the excimer laser, the stability of the laser output is low (usually, about ± 3%), and the process accuracy tends to be deteriorated by this influence. In addition, by incorporating an excimer laser,
The installation area of the apparatus must be increased, and the demand for space saving cannot be met. Furthermore, excimer lasers are expensive and maintenance costs such as gas exchange are large.

Therefore, the present invention can easily control the pulse waveform of a laser beam, can increase the stability of laser output, and can meet the demand for space saving and cost reduction. An object of the present invention is to provide a laser processing apparatus and method.

[0006]

In order to solve the above-mentioned problems, a laser processing apparatus according to the present invention comprises a light source device having a plurality of solid-state laser devices for generating a pulsed laser beam, and a plurality of light sources from the light source device. A composite optical system that superimposes a laser beam on a target surface and a timing adjustment device that adjusts the operation timing of the plurality of solid-state laser devices to form a pulse having a predetermined temporal waveform.

In the laser processing apparatus, since a light source apparatus having a plurality of solid-state laser apparatuses is used, the stability of the laser output can be made relatively high, and space saving and cost reduction can be achieved. it can. Furthermore, since the respective laser beams are superimposed and incident on the target surface using the synthetic optical system while adjusting the operation timings of the plurality of solid-state laser devices by the timing adjustment device, the solid-state laser has conventionally been relatively weak. An arbitrary pulse shape can be generated while apparently increasing the laser output.

The solid-state laser device is provided with a laser oscillation element for generating a laser beam having a relatively low wavelength, and the laser beam from this laser oscillation element is shortened to a target value by an appropriate harmonic generator. Out.

A laser processing apparatus generally includes a stage on which a workpiece to be processed is mounted and three-dimensionally moved, and a stage which is moved with respect to the light source device and the synthesizing optical system to apply a laser beam to the workpiece. And a computer device for controlling the light source device and the driving device in an integrated manner.

Another laser processing apparatus according to the present invention comprises a light source device having a plurality of solid-state laser devices for generating a pulsed laser beam, and a plurality of laser beams from the light source device superimposed on a target surface. In a laser processing apparatus having a synthetic optical system for incidence, the light source device includes 2N solid-state laser devices that generate linearly polarized light, where N is a natural number, and n is a natural number less than or equal to N and is set to a predetermined polarization plane. The (2n-1) th solid-state laser device and the (2n) -th solid-state laser device set to a polarization plane different from the predetermined polarization plane constitute an nth light source unit, and the combining optical system There are N polarization beam splitters that combine a pair of laser beams emitted from each light source unit to emit N sets of laser beams, and a laser beam that bundles the N sets of laser beams. And a homogenizing optical system for incident superimposed on the target surface split laser beams as well as degrade the beam into a plurality of laser beams as a uniform beam of substantially the same size.

In the laser processing apparatus, since a plurality of solid-state laser devices are used, the stability of the laser output can be made relatively high, and the space and cost can be reduced. Further, since a plurality of generated laser beams are spatially overlapped, a pulse whose laser output is apparently increased can be generated. Furthermore, since the plurality of superposed laser beams are divided and superimposed on the target surface as a uniform beam having substantially the same size after division, the uniformity of the light amount distribution of the laser beam incident on the target surface can be ensured. Uniform laser processing becomes possible.
Further, in the laser processing apparatus, the light source device includes a plurality of light source units each including a pair of solid-state laser devices having different polarization planes, and the combining optical system combines the pair of laser beams emitted from each of the light source units to N N polarized beam splitters for emitting a set of laser beams, a laser beam obtained by bundling the N sets of laser beams is decomposed into a plurality of laser beams, and the divided laser beams are formed as uniform beams of substantially the same size on a target surface. And a uniform optical system for superimposing the laser beam on the target surface, so that the uniformity of the light amount distribution can be secured while reducing the polarization of the polarization plane of the laser beam incident on the target surface, and more uniform laser processing can be performed. Will be possible.

In a preferred aspect of the above apparatus, the number of solid-state laser devices included in the light source device is an odd number, and the solid-state laser device that does not constitute the light source unit causes a circularly polarized laser beam to be incident on the synthetic optical system. And

In the above-mentioned laser processing apparatus, since the solid-state laser device which does not constitute the light source unit causes the circularly polarized laser beam to be incident on the synthetic optical system, it is possible to reduce the polarization characteristic of the laser beam incident on the target surface more than the polarization. it can.

In a preferred embodiment of the above device, the solid-state laser device which does not constitute a light source unit is provided with a quarter-wave plate for changing linearly polarized light to circularly polarized light. In this case, circularly polarized light can be easily obtained.

In a preferred embodiment of the above-mentioned apparatus, the (2n)
A second solid-state laser device is provided with a half-wave plate for changing a polarization plane of a laser beam. In this case, the polarization plane of the laser beam can be easily changed in the orthogonal direction.

In a preferred aspect of the above-described apparatus, the timing adjusting apparatus forms a pulse having a predetermined temporal waveform by connecting a plurality of laser beams in time series. In this case, the pulse waveform can be attenuated with time, which is suitable for application to a laser annealing device that requires control of the cooling time.

In a preferred aspect of the above-mentioned device, the solid-state laser device is provided with an optical element for adjusting an optical path length at an emission port of a laser beam. In this case, it is possible to prevent a speckle pattern from being generated on the target surface and hindering uniform processing.

A laser processing method according to the present invention comprises the steps of preparing a plurality of solid-state laser devices and generating pulsed laser beams from the plurality of solid-state laser devices with a predetermined time difference; A step of spatially superposing the plurality of laser beams, and a step of superposing the plurality of superposed laser beams as a uniform beam of substantially the same size after division and incident the same on a target surface.

In the above-described laser processing method, since a plurality of solid-state laser devices are used, the stability of the laser output can be made relatively high, and the space and cost can be reduced. In addition, since pulsed laser beams are generated from a plurality of solid-state laser devices with a predetermined time difference, and the generated laser beams are spatially overlapped, an arbitrary pulse shape can be formed while apparently increasing the laser output. Can be generated. Furthermore, since a plurality of superposed laser beams are superimposed as a uniform beam of substantially the same size after division and incident on the target surface,
The uniformity of the light amount distribution of the laser beam incident on the target surface can be ensured, and more uniform laser processing can be performed.

[0020]

[First Embodiment] FIG. 1 is a view for explaining the structure of a laser processing apparatus according to a first embodiment of the present invention.

This laser processing apparatus comprises a light source device 20 having four solid-state laser devices 21 to 24 for generating a laser beam in the ultraviolet region, and a laser beam emitted from each of the solid-state laser devices 21 to 24 by appropriately combining them. A coupling optical system 30 for generating a pair of laser beams L1 and L2;
The telescope optical system 40 in which the two sets of laser beams L1 and L2 that have passed through are enlarged and superimposed spatially, and the laser beams L1 and L2 superimposed by the telescope optical system 40 are decomposed and divided into a plurality of laser beams. A homogenizer 5 which is a homogenizing optical system that superimposes the laser beam on the processing surface IS as a uniform beam of the same size and makes it incident.
0 and each of the solid-state laser devices 21 to 21 constituting the light source device 20.
24, and a control computer 60 which is a timing adjustment device for adjusting the operation timing. Note that the coupling optical system 30, the telescope optical system 40, and the homogenizer 50 constitute a combined optical system.

The light source device 20 includes an even number of first to light sources having the same structure.
Four solid-state laser devices 21 to 24 are provided. The first and second solid-state laser devices 21 and 22 constitute a first light source unit, and the third and fourth solid-state laser devices 23 and 24 constitute a second light source unit. Each solid-state laser device 2
1 to 24 are arranged so that the main body thereof generates linearly polarized light having a polarization plane in the YZ plane. However, for the even-numbered second and fourth solid-state laser devices 22 and 24, the beam exit ports Half-wave plates 28 and 29 for rotating the polarization plane by 90 degrees are provided in the vicinity. As a result, the laser beams L11 and L21 incident on the coupling optical system 30 from the first and third solid-state laser devices 21 and 23 become linearly polarized light having a polarization plane in the YZ plane, and the second and fourth solid-state laser devices 22, 2
4 and the laser beams L12 and L incident on the coupling optical system 30.
Reference numeral 22 denotes linearly polarized light having a plane of polarization in the XZ plane.

Each of the solid-state laser devices 21 to 24 generates a Y-polarized laser beam having a wavelength of about 1.053 μm.
A solid-state laser element 26 such as LF;
And a wavelength conversion element 27 that is a harmonic generator that converts the laser light emitted from 6 into triple harmonics with high efficiency.

The coupling optical system 30 includes a deflecting turn mirrors 31 and 32 and a beam combining polarization beam splitter 3.
4 is provided. Laser beams L11 from the first and second solid-state laser devices 21 and 22 constituting the first light source unit,
L12 is deflected by the turn mirrors 31 and 32 and is incident on a pair of incident surfaces of one of the polarization beam splitters 34, where they are combined to form a laser beam L1. The laser beams L21 and L22 from the third and fourth solid-state laser devices 23 and 24 constituting the second light source unit are also
2 and is incident on a pair of incident surfaces of the other polarizing beam splitter 34, where it is combined to form a laser beam L2.
Becomes

FIG. 2 is a diagram for explaining the operation of the polarizing beam splitter 34. The laser beam L11 from the first solid-state laser device 21 enters the first polarization beam splitter 34 as P-polarized light, is reflected by the polarization separation surface 43a, and
The laser beam L12 from the solid-state laser device 22 enters the first polarization beam splitter 34 as S-polarized light and passes through the polarization splitting surface 43a. Thereby, both laser beams L
11 and L12 are combined to form a laser beam L1 in a randomly polarized (naturally polarized) state having no polarization in the polarization direction.

The laser beam L21 from the third solid-state laser device 23 enters the second polarization beam splitter 34 as P-polarized light, is reflected by the polarization separation surface 43a, and is reflected by the laser beam L22 from the fourth solid-state laser device 24. Enters the second polarization beam splitter 34 as S-polarized light and passes through the polarization splitting surface 43a. Thereby, both laser beams L2
1 and L22 are combined to form a randomly polarized laser beam L2 having no polarization in the polarization direction.

Returning to FIG. 1, the telescope optical system 40
Includes a concave lens 41 and a convex lens 42. The two sets of laser beams L1 and L2 emitted from the coupling optical system 30 are translated in close proximity, diverged through a concave lens 41, and then converted into a parallel light beam by a convex lens 42. As a result, the beam diameter of each laser beam L1, L2 increases, and both laser beams L1, L2
Are in a state of being spatially overlapped and bundled over substantially the entirety. The magnification of both laser beams L1 and L2 is appropriately adjusted in accordance with the opening size of the homogenizer 50.
In the above description, the telescope optical system 40 is a Galileo type including concave and convex lenses. However, the telescope optical system 40 may be a Keplerian type including a pair of convex lenses. The laser beams L1, L2 can be spatially substantially overlapped while increasing the beam diameter.

The homogenizer 50 forms a large number of secondary light sources by once two-dimensionally decomposing the laser beams L1 and L2 by the cylindrical lens arrays CA1 to CA4, and superimposes these secondary light sources on the processing surface IS. And make the laser irradiation uniform.

FIG. 3 is a diagram for explaining the structure of the homogenizer 50 in more detail. As is clear from the drawing, the homogenizer 20 includes first to fourth cylindrical lens arrays CA1 to CA4 and a condenser lens 52 as a convex lens. Here, the first and third cylindrical lens arrays CA1, CA3 have a curvature in the YZ section, and the second and fourth cylindrical lens arrays CA2, CA4 are X
It has a curvature in the Z section. In this case, the homogenizer 2
0 is composed of four cylindrical lens arrays so that the beam size projected on the irradiation surface IS can be adjusted for each axis (X, Y). However, if it is not necessary to make the beam size variable, a homogenizer is used. Reference numeral 20 may also be a two-lens array configuration using one cylindrical lens array having a curvature in each of the XZ section and the YZ section.

The laser beams L1 and L2 incident on the homogenizer 50 are divided into six in the Y direction by the first and third cylindrical lens arrays CA1 and CA3 in accordance with the number of segments constituting the array. The laser beams L1 and L2 are also divided into six in the X direction by the second and fourth cylindrical lens arrays CA2 and CA4 in accordance with the number of segments constituting the arrays. As a result, a secondary light source divided into 6 × 6 is formed. The light beam from the split secondary light source enters the condenser lens 21. Each 2 incident on the condenser lens 21
The light beam from the next light source is superimposed on the irradiated surface IS arranged at the back focus position of the condenser lens 21 and uniformly irradiates the rectangular area. In the above description, the laser beam is divided into six parts for each axis (X, Y) using the cylindrical lens arrays CA1 to CA4, but the number of divisions is arbitrary. When the number of divisions increases, the uniformity of a normally formed uniform beam improves, but the loss of light amount increases.

The laser beams L1 and L2 are displaced in the Y direction, are not completely overlapped, and are partly protruding. However, if the beam does not overflow from the homogenizer 50, no light amount loss occurs.
At this time, the displacement of the laser beams L1 and L2 in the Y direction is
It is desirable to set the interval for one segment of the first cylindrical lens array CA1. This makes it possible to make the spatial intensity distribution of the laser beam incident on each segment, in particular, the segments at both the upper and lower ends uniform.

Returning to FIG. 1, the control computer 60
Are the solid-state laser devices 21 to 2 constituting the light source device 20.
The oscillation timing of these solid-state laser devices 21 to 24 is adjusted by outputting a trigger signal to the solid-state laser device 4. Thereby, the emission timing of the laser beams L11 to L22 from each of the solid-state laser devices 21 to 24 is adjusted, and the overall
One pulse shape can be formed.

FIG. 4 is a diagram for explaining a method of forming one pulse by connecting the laser beams L11 to L22 with an appropriate time difference. First, a laser beam L11 is emitted from the first solid-state laser device 21. Next, at the delay time t1, the second
A laser beam L12 is emitted from the solid-state laser device 22.
Next, the laser beam L21 is emitted from the third solid-state laser device 23 at the delay time t2. Next, the laser beam L22 is emitted from the fourth solid-state laser device 24 at the delay time t3. The intensity of each of the laser beams L11 to L22 and the delay time t1 to
By appropriately adjusting t3, a pulse PL having an arbitrary waveform can be equivalently formed. Processing with such a long pulse PL is a particularly effective irradiation method in a laser annealing apparatus that needs to control the cooling time.

The intensity of each of the laser beams L11 to L22 can be appropriately adjusted by, for example, attenuating the output of each of the solid-state laser devices 21 to 24 using a filter. Delay time t
1 to t3 can be adjusted by the timing of a trigger signal supplied from the control computer 60 to each of the solid-state laser devices 21 to 24.

The operation of the laser processing apparatus according to the first embodiment shown in FIG. 1 will be described below. First, a trigger signal is output from the control computer 60 to each of the solid-state laser devices 21 to 24 at an appropriate timing, so that each of the solid-state laser devices 21 to 24 is output.
Laser beam L11 with an appropriate time difference and polarization plane
To L22. The laser beams L11 to L22 are combined by the combining optical system 30, and become two sets of laser beams L1 and L2 that translate slightly away. Both laser beams L1, L2
Are transmitted through the telescope optical system 40, the beam diameter is enlarged as a parallel light beam, and spatially overlapped. The laser beams L1 and L2 that have passed through the telescope optical system 40 are decomposed into a 6 × 6 secondary light source by the homogenizer 50, and are incident on the processing surface IS in a superimposed manner.

At this time, since the solid-state laser devices 21 to 24 are used as the light source device 20, the stability of the laser output is increased as compared with the case where a gas laser such as an excimer laser is used (usually about ± 1%). Less than). Therefore, the intensity and pulse waveform of the laser beam can be stabilized. In addition, since the solid-state laser devices 21 to 24 are small and inexpensive as compared with a gas laser or the like, space saving and cost reduction of the laser processing device can be achieved, and maintenance is simple and inexpensive. In addition, four solid-state laser devices 2
The laser beams L11 to L22 are generated at predetermined time intervals from the laser beams 1 to 24, respectively, and the generated laser beams L11 to L22 are spatially overlapped, so that an arbitrary pulse shape is generated while apparently increasing the laser output. can do. Thereby, the irradiation area on the processing surface IS can be increased to some extent, and the degree of freedom of the process can be increased. In addition, homogenizer 5
Since 0 is used to make the light amount distribution of the laser beam incident on the processing surface IS uniform, it becomes possible to perform uniform laser processing of the target area.

In the first embodiment described above, the number of the solid-state laser devices 21 to 24 constituting the light source device 20 is four, but 2N (that is, any even-numbered) solid-state laser devices where N is an arbitrary natural number. Thereby, a light source device can be configured. In this case, n is a natural number equal to or less than N, and the laser beam from the (2n-1) th solid-state laser device is, for example, P-polarized light, and the laser beam from the (2n) -th solid-state laser device is S-polarized light. . In the coupling optical system 30, the (2n-1) -th and (2n) -th polarization beam splitters using the n-th polarization beam splitter constituting the same are used.
A pair of laser beams from the second solid-state laser device are combined into random polarized light, and N sets of such randomly polarized laser beams can be obtained. In the telescope optical system 40, each of the N sets of laser beams is expanded and bundled, and the homogenizer 5
In the case of 0, the bundled laser beam is decomposed into a number of secondary light sources and superimposed on the processing surface IS so as to be uniformly incident.

If the light source device is constituted by using a large number of solid-state laser devices and the oscillation timing and the like of each solid-state laser device are adjusted, the pulses that can be equivalently generated become longer, and various waveforms are generated. It can have. [Second Embodiment] FIG. 5 is a view for explaining the structure of a laser processing apparatus according to a second embodiment of the present invention.

The laser processing apparatus according to the second embodiment is obtained by modifying the light source device 20 according to the first embodiment to form a light source device 120 including three solid-state laser devices 21, 22, and 123. The same reference numerals are given to the same parts as those described above, and redundant description will be omitted.

In this case, the light source device 120 includes the first and second solid-state laser devices 21 and 22 and a third solid-state laser device 123 that generates linearly polarized light having an appropriate polarization plane.
The third solid-state laser device 123 is located near the beam exit port.
A 波長 wavelength plate 129 is provided. Thus, the laser beam L20 incident on the coupling optical system 130 is converted from linearly polarized light to circularly polarized light. The optical path of the laser beam L20 that has entered the coupling optical system 130 is changed through the turn mirrors 31 and 32, and travels in parallel with the laser beam L1 combined by the polarization beam splitter 34 in close proximity.

In the second embodiment described above, the laser beam L20 from the odd third solid-state laser device 123 which does not constitute the light source units 21 and 22 for generating random polarized light is converted into circularly polarized light. This is in consideration of the fact that there is a possibility that a process problem may occur because a difference in the absorptance, the reflectivity, and the like occurs depending on the polarization direction incident on the processing surface IS. Therefore, if there is no problem with linearly polarized light in the process, the 直線 wavelength plate 129 may be omitted.

In the second embodiment, the light source device 1
Although the number of solid-state laser devices constituting 20 is three, the light source device can be constituted by 2N + 1 (that is, any odd-numbered) solid-state laser devices, where N is an arbitrary natural number. In this case, up to 2N units, the light source device 120 and the coupling optical system 130 are arranged and configured similarly to the light source device and the coupling optical system of the first embodiment, and the linearly polarized light from the remaining one solid-state laser device is: The light is made to enter the coupling optical system 130 as circularly polarized light by the 波長 wavelength plate 129. [Third Embodiment] FIG. 6 is a view for explaining the structure of a laser processing apparatus according to a third embodiment. The device of the third embodiment is
This is a system incorporating the laser processing device of the first embodiment.

The illustrated laser annealing apparatus comprises a stage 10 on which a work W, which is a glass plate having a semiconductor thin film such as amorphous Si formed on the surface, is mounted and can be moved three-dimensionally and smoothly. A light source device 20 including a plurality of solid-state laser devices 21 to 24 for generating an ultraviolet laser beam for heating a semiconductor thin film, and a plurality of laser beams from each of the solid-state laser devices 21 to 24 are combined and bundled. An optical system 30, a telescope optical system 40 for enlarging and spatially superimposing the laser beam passing through the coupling optical system 30, and decomposing the superimposed laser beam into a plurality of laser beams and processing them as a uniform beam of the same size. Homogenizer 50 for superimposing and incident on surface IS
And a position sensor 70 for detecting the position of the stage 10 on which the work W is placed, and a stage drive as drive means for appropriately moving the stage 10 by a required amount with respect to the homogenizer 50 or the like based on the detection result of the position sensor 70. Device 80
And a computer main controller 160 for controlling the operation of each part of the entire laser annealing apparatus.

The operation of the apparatus shown in FIG. 6 will be described below. First, the work W is transported and placed on the stage 10 of the laser annealing apparatus. Next, while moving the stage 10 in the X-axis direction with respect to the irradiation optical system such as the homogenizer 50, the work W is irradiated with the laser beam LB from the irradiation optical system.
Inject on top. Thus, the main scanning of the work W by the laser beam LB is performed. Further, by performing sub-scanning in which the stage 10 is moved stepwise in the Y-axis direction each time the main scanning is completed, laser annealing on the entire surface of the work W becomes possible. If a laser beam LB that is linear rather than rectangular is formed by the homogenizer 50 or the like, laser annealing on the entire surface of the work W can be performed simply by moving the stage 10 in the X-axis direction.

At the time of scanning with the laser beam LB, a pulse waveform having a desired distribution with time is formed by adjusting the operation timing of each of the solid-state laser devices 21 to 24. As a result, the cooling time can be controlled, and various needs can be met. The irradiation areas of the continuous pair of laser beams LB can be overlapped by an appropriate amount by appropriately controlling the driving of the stage 10, but they can also be joined together without gaps.

Although the present invention has been described with reference to the embodiment, the present invention is not limited to the above embodiment. For example, in the above embodiment, the half-wave plates 28 and 29
Is used to rotate the polarization plane, but if the second and fourth solid-state laser devices 22 and 24 themselves are rotated 90 degrees around the optical axis, the half-wave plates 28 and 29 become unnecessary. . That is, the polarization planes of the laser beams L11 and L21 and the polarization planes of the laser beams L12 and L22 may be made to enter the coupling optical system 30 in a state orthogonal to each other.

In the above embodiment, the wavelength conversion element 2
7, the ultraviolet light is generated. However, if the solid-state laser element 26 that generates the ultraviolet light by itself is used, the loss of energy density due to the use of the wavelength conversion element 27 can be reduced.

In the case where a speckle pattern is formed by a laser beam on the processing surface IS, FIG.
As shown in (1), elements 21a to 24a for adjusting the optical path length, that is, the phase, can be provided at the emission ports of the solid-state laser devices 21 to 24. Although not shown, in the case of the second embodiment, an element for adjusting the optical path length can be arranged at the exit of each of the solid-state laser devices 21, 22, 123. Each element 2
1a to 24a can be simply quartz glass plates, and the speckle patterns can be made inconspicuous by adjusting the phases of the solid-state laser devices 21 to 24.

Further, the laser processing apparatus of the above embodiment is
It is not only used as a laser annealing device for liquid crystals or semiconductors, but can be applied to surface modification of various materials and other various processes.

[0050]

As is clear from the above description, according to the laser processing apparatus of the present invention, the stability of the laser output can be made relatively high, and the space and cost can be reduced. it can. Furthermore, an arbitrary pulse shape can be generated while apparently increasing the laser output.

Further, according to another laser processing apparatus of the present invention, the stability of the laser output can be made relatively high, and the space can be saved and the cost can be reduced. Furthermore, an apparently increased pulse of the laser output can be generated, and more uniform laser processing can be performed.

Also, according to the laser processing method of the present invention, the stability of the laser output can be made relatively high, and the space can be saved and the cost can be reduced. Also, an arbitrary pulse shape can be generated while apparently increasing the laser output. Furthermore, the uniformity of the light amount distribution of the laser beam incident on the target surface can be ensured, and more uniform laser processing can be performed.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a structure of a laser processing apparatus according to a first embodiment.

FIG. 2 is a diagram illustrating the operation of a polarization beam splitter that forms a coupling optical system.

FIG. 3 is a diagram illustrating the structure of a homogenizer.

FIG. 4 is a diagram illustrating a combined pulse waveform of a laser beam projected on a processing surface.

FIG. 5 is a diagram illustrating a structure of a laser processing apparatus according to a second embodiment.

FIG. 6 is a diagram illustrating a structure of a laser annealing apparatus according to a third embodiment.

FIG. 7 is a diagram illustrating a modification of the laser processing apparatus according to the first embodiment.

[Explanation of symbols]

 Reference Signs List 10 stage 20 homogenizer 20 light source device 21-24 solid-state laser device 26 solid-state laser device 27 wavelength conversion device 28,29 wavelength plate 30 coupling optical system 34 polarization beam splitter 40 telescope optical system 50 homogenizer 60 computer for control

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // B23K 101: 40 B23K 101: 40

Claims (9)

[Claims] A light source device having a plurality of solid-state laser devices for generating a pulsed laser beam; a combining optical system for superimposing a plurality of laser beams from the light source device on a target surface; A timing adjusting device that adjusts operation timing of the solid-state laser device to form a pulse having a predetermined temporal waveform. 2. A laser comprising: a light source device having a plurality of solid-state laser devices for generating a pulsed laser beam; and a combining optical system for superimposing a plurality of laser beams from the light source device on a target surface. In the processing apparatus, the light source device includes 2N solid-state laser devices that generate linearly polarized light, where N is a natural number, and that n is a natural number equal to or less than N and is set to a predetermined polarization plane (2n−
The 1) -th solid-state laser device and the (2n) -th solid-state laser device set to a polarization plane different from the predetermined polarization plane constitute an n-th light source unit, and the combining optical system includes: N polarization beam splitters for combining a pair of laser beams emitted from the unit to emit N sets of laser beams, and decomposing and dividing the laser beam obtained by combining the N sets of laser beams into a plurality of laser beams A laser beam processing apparatus, comprising: a homogenizing optical system that superimposes the applied laser beam as a uniform beam of substantially the same size on the target surface. 3. The solid-state laser device included in the light source device is an odd number, and the solid-state laser device that does not constitute the light source unit causes a circularly polarized laser beam to be incident on the synthetic optical system. The laser processing apparatus according to claim 2, wherein 4. The laser processing apparatus according to claim 3, wherein the solid-state laser device that does not form the light source unit includes a quarter-wave plate that changes linearly polarized light to circularly polarized light. 5. The laser processing apparatus according to claim 2, wherein the (2n) th solid-state laser device includes a half-wave plate for changing a polarization plane of the laser beam. . 6. The laser processing apparatus according to claim 2, further comprising a timing adjustment device that adjusts operation timings of the plurality of solid-state laser devices to form a pulse having a predetermined temporal waveform. The laser processing apparatus according to any one of the above. 7. The laser according to claim 1, wherein the timing adjusting device connects the plurality of laser beams in time series to form a pulse having a predetermined temporal waveform. Processing equipment. 8. The laser processing apparatus according to claim 1, wherein the solid-state laser device includes an optical element for adjusting an optical path length at a laser beam emission port. 9. A step of preparing a plurality of solid-state laser devices and generating a pulsed laser beam from each of the plurality of solid-state laser devices with a predetermined time difference; A laser processing method comprising: a step of spatially superposing; and a step of dividing the superposed laser beams into a uniform beam having substantially the same size after division and causing the laser beam to enter a target surface.