JP3530484B2 - Laser processing apparatus and method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing apparatus and method using a pulse laser, and particularly to a laser processing apparatus and method suitable for annealing a semiconductor thin film.

[0002]

2. Description of the Related Art Ultraviolet light is mainly used in semiconductor processes such as annealing, lithography and doping because it is 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 into polycrystalline Si using 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 a uniform beam of the same size is superposed and irradiated on a processed surface.

[0004]

In the above laser processing apparatus, the pulse waveform of the laser beam can hardly be controlled, so that the degree of freedom in the process becomes small. Further, the stability of the laser output is low (usually reaching about ± 3%) due to the limit of the performance of the excimer laser, and this tends to deteriorate the process accuracy. Also, by incorporating an excimer laser,
There is no choice but to increase the installation area of the device, and it is not possible to meet the demand for space saving. Furthermore, excimer lasers are expensive and maintenance costs such as gas exchange are high.

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

[0006]

In order to solve the above problems, a laser processing apparatus according to the present invention includes a light source device having a plurality of solid-state laser devices for generating pulsed laser beams, and a plurality of light source devices. Combine and bundle laser beams
Healing coupling optics and multiple laser beams that go through the coupling optics
Telescope optical system that enlarges the frame and spatially overlaps
And multiple laser beams
And a uniform beam of approximately the same size.
A homogenizer for superimposing and entering the work surface and a timing adjusting device for adjusting operation timings of the plurality of solid-state laser devices to form a pulse having a predetermined temporal waveform are provided.

In the above laser processing apparatus, since the one having a plurality of solid-state laser devices is used as the light source device, the stability of the laser output can be made relatively high, and space saving and cost reduction can be achieved. it can. Also ,
The laser output, which has been considered to be comparatively weak in the conventional solid-state laser, is used because the laser beams are made to overlap and enter the target surface by using the synthetic optical system while adjusting the operation timing of the plurality of solid-state laser devices by the timing adjustment device. Arbitrary pulse shapes can be generated with an apparent increase. In addition, the homogenizer provides a more uniform laser.
Processing becomes possible. The presence of the telescope optical system
The laser beam while keeping the homogenizer relatively small.
A sufficient homogenization of the system can be achieved.

The solid-state laser device is provided with a laser oscillating element for generating a laser beam of a relatively low wavelength, and the laser beam from this laser oscillating element is shortened to a target value with an appropriate harmonic generator. Can be emitted.

In addition, the laser processing apparatus normally moves a stage with respect to the light source device and the combining optical system, and a stage on which a work to be processed is placed and moves three-dimensionally. The driving means for moving the object surface by an appropriate timing and distance, and the computer device for integrally controlling the light source device and the driving means are adopted.

Another laser processing apparatus according to the present invention is 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 device including a combining optical system for making incident light, a 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 equal to or less than 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 the n-th light source unit, and the combining optical system. , 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 N polarization beamsplitters.
The N sets of laser beams that have passed through the beam splitter
Telescope optics that overlap each other and N sets of lasers
And a homogenizing optical system for splitting a laser beam in which the the beams are overlapped into a plurality of laser beams and for superposing the split laser beams as a uniform beam of substantially the same size on a target surface.

Since a plurality of solid-state laser devices are used in the above laser processing apparatus, the stability of laser output can be made relatively high, and space saving and cost reduction can be achieved. Further, since the generated laser beams are spatially overlapped with each other, it is possible to generate pulses in which the laser output is apparently increased. Further, since a plurality of laser beams that have been overlapped are divided and superposed as a uniform beam of substantially the same size to be incident on the target surface, it is possible to secure the uniformity of the light amount distribution of the laser beam incident on the target surface. Uniform laser processing becomes possible.
Further, in the above 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 couples a pair of laser beams emitted from the respective light source units, respectively, to generate N laser beams. and N of the polarization beam splitter for emitting a set of laser beams, the N
Enlarge N sets of laser beams that have passed through the polarization beam splitter
And a spatially superimposing telescopic optical system, and a laser beam obtained by superimposing N sets of laser beams is divided into a plurality of laser beams, and the divided laser beams are formed on the target surface as a uniform beam of substantially the same size. Since it is equipped with a homogenizing optical system that makes the laser beams incident on top of each other, it is possible to secure the uniformity of the light amount distribution while reducing the deviation of the polarization plane of the laser beam incident on the target surface, and it is possible to perform more uniform laser processing. become. The existence of this telescope optical system
Keeps the uniform optical system relatively small while
Sufficient homogenization of the membrane can be achieved.

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 form a light source unit causes a circularly polarized laser beam to enter the combining optical system. And

In the above laser processing apparatus, since the solid-state laser apparatus that does not form the light source unit causes the circularly polarized laser beam to enter the combining optical system, it is possible to reduce the deviation of the polarization characteristics of the laser beam entering the target surface. it can.

In a preferred aspect of the above-mentioned device, the solid-state laser device which does not constitute the light source unit is equipped with a quarter-wave plate which changes linearly polarized light into circularly polarized light. In this case, circularly polarized light can be easily obtained.

In a preferred embodiment of the above apparatus, the second (2n)
The th solid-state laser device is equipped with a half-wave plate that changes the plane of polarization of the laser beam. In this case, the plane of polarization of the laser beam can be easily changed to the orthogonal direction.

In a preferred aspect of the above device, the timing adjusting device is characterized in that a plurality of laser beams are connected in time series to form a pulse having a predetermined temporal waveform. 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 the optical path length at the exit of the laser beam. In this case, it is possible to prevent a speckle pattern from being generated on the target surface and hindering uniform processing.

The 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, respectively. The process of combining and bundling multiple laser beams of
A step of enlarging and spatially superimposing a plurality of laser beams, and a step of dividing the superposed laser beams into a uniform beam of substantially the same size after the division and making the laser beams incident on a target surface. To do.

In the above laser processing method, since a plurality of solid-state laser devices are used, the stability of laser output can be made relatively high, and space saving and cost reduction can be achieved. Further, since a plurality of solid-state laser devices generate pulsed laser beams with a predetermined time difference and spatially overlap the generated laser beams, the laser output can be increased in appearance to produce an arbitrary pulse shape. Can be generated. Furthermore, since a plurality of superposed laser beams are split and superposed as a uniform beam of approximately the same size to be 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 becomes possible. It should be noted that the multiple laser beams bundled together are expanded to create a space.
The optical system for homogenization is relatively
Achieve sufficient homogenization of the laser beam while keeping it small
be able to.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] FIG. 1 is a diagram for explaining the structure of a laser processing apparatus according to a first embodiment of the present invention.

In this laser processing apparatus, 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 are appropriately combined to obtain 2 Combined optical system 30 for generating a pair of laser beams L1 and L2, and combined optical system 30
Telescope optical system 40 that magnifies and spatially superimposes two sets of laser beams L1 and L2 that have passed through, and laser beams L1 and L2 superposed by telescope optical system 40 are decomposed into a plurality of laser beams and split. A homogenizer 5 which is a homogenizing optical system that superimposes the generated laser beam on the processing surface IS as a uniform beam having the same size.
0, and the solid-state laser devices 21 to 21 that configure the light source device 20.
A control computer 60, which is a timing adjustment device for adjusting the operation timing of 24, is provided. The coupling optical system 30, the telescope optical system 40, and the homogenizer 50 form a synthetic optical system.

The light source device 20 includes first to even first 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 form a first light source unit, and the third and fourth solid-state laser devices 23 and 24 form a second light source unit. Each solid-state laser device 2
1 to 24 are arranged so that their main bodies generate linearly polarized light having a plane of polarization in the YZ plane, but for the even-numbered second and fourth solid-state laser devices 22 and 24, Half-wave plates 28 and 29 for rotating the plane of polarization 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
Laser beams L12, L incident on the coupling optical system 30 from 4
22 is linearly polarized light having a plane of polarization in the XZ plane.

Each of the solid-state laser devices 21 to 24 emits Y which is a linearly polarized laser beam having a wavelength of about 1.053 μm.
A solid-state laser element 26 such as LF, and this solid-state laser element 2
The wavelength conversion element 27, which is a harmonic generator that converts the laser light emitted from the laser diode 6 into a tripled harmonic with high efficiency.

The combining optical system 30 includes turn mirrors 31 and 32 for deflection and a polarization beam splitter 3 for beam combination.
4 and. Laser beams L11 from the first and second solid-state laser devices 21 and 22 which constitute 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 polarization beam splitter 34, and is combined here to become a laser beam L1. The laser beams L21 and L22 from the third and fourth solid-state laser devices 23 and 24 which form the second light source unit are also turned mirrors 31 and 3.
The light beam is deflected by 2 and is incident on a pair of incident surfaces of the other polarization beam splitter 34, where it is combined to form a laser beam L2.
Becomes

FIG. 2 is a diagram for explaining the function of the polarization 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 splitting 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. As a result, both laser beams L
11 and L12 are combined to form a laser beam L1 in a randomly polarized (naturally polarized) state in which the polarization direction is not biased.

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 splitting surface 43a, and is 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. As a result, both laser beams L2
1, L22 are combined to form a randomly polarized laser beam L2 having no polarization direction deviation.

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 close to each other, diverged via the concave lens 41, and then made into a parallel light flux by the convex lens 42. As a result, the beam diameters of the laser beams L1 and L2 are increased, and both laser beams L1 and L2 are
Are in a state of being bundled so as to be spatially overlapped almost all over. The expansion rates of both laser beams L1 and L2 are appropriately adjusted according to the opening size of the homogenizer 50.
In the above description, the telescope optical system 40 is the Galileo type consisting of the concave and convex lenses, but the telescope optical system 40 can also be the Kepler type consisting of a pair of convex lenses, and by this, similarly to the above, The laser beams L1 and L2 can be spatially overlapped while increasing the beam diameters thereof.

The homogenizer 50 temporarily decomposes the laser beams L1 and L2 two-dimensionally by the cylindrical lens arrays CA1 to CA4 to form a large number of secondary light sources, and superimposes these secondary light sources on the processed surface IS. Then, it has a function of making 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 figure, the homogenizer 20 includes first to fourth cylindrical lens arrays CA1 to CA4 and a convex condenser lens 52. Here, the first and third cylindrical lens arrays CA1 and CA3 have a curvature in the YZ section, and the second and fourth cylindrical lens arrays CA2 and CA4 are X.
It has a curvature in the Z section. In this case, homogenizer 2
0 is composed of four cylindrical lens arrays so that the beam size projected on the illuminated surface IS can be adjusted with respect to each axis (X, Y). However, if the beam size does not need to be variable, the homogenizer can be used. The lens 20 may have a total of two lens array configurations using one cylindrical lens array each having a curvature in 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 corresponding to the number of segments forming the array. Further, the laser beams L1 and L2 are also divided by the second and fourth cylindrical lens arrays CA2 and CA4 into six in the X direction corresponding to the number of segments forming the array. As a result, a 6 × 6 divided secondary light source is formed. The split light beam from the secondary light source enters the condenser lens 21. Each 2 incident on condenser lens 21
The light beam from the next light source is superposed on the illuminated surface IS arranged at the back focus position of the condenser lens 21 and uniformly illuminates the rectangular area. In the above description, the laser beam is divided into 6 with respect to each axis (X, Y) using the cylindrical lens arrays CA1 to CA4, but the number of divisions is arbitrary. If the number of divisions is large, the uniformity of a uniform beam that is usually formed is improved, but the light amount loss is increased.

The laser beams L1 and L2 are displaced in the Y direction, do not completely overlap with each other, and are partly protruding. However, if the beam does not overflow from the homogenizer 50, no light amount loss occurs.
At this time, the positional deviation 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, especially on the upper and lower ends, uniform.

Returning to FIG. 1, the control computer 60.
Are the solid-state laser devices 21 to 2 that constitute the light source device 20.
By outputting a trigger signal to No. 4, the oscillation timing of these solid-state laser devices 21 to 24 is adjusted. As a result, the emission timings of the laser beams L11 to L22 from the solid-state laser devices 21 to 24 are adjusted, and the total of 1
Two pulse shapes can be formed.

FIG. 4 is a diagram for explaining a method of connecting the laser beams L11 to L22 with an appropriate time difference to form one pulse. First, the 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, at the delay time t2, the laser beam L21 is emitted from the third solid-state laser device 23. Next, at the delay time t3, the laser beam L22 is emitted from the fourth solid-state laser device 24. The intensity of each laser beam L11 to L22 and the delay time t1 to
By appropriately adjusting t3, it is possible to equivalently form a pulse PL having an arbitrary waveform. The 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 attenuating the output of each of the solid-state laser devices 21 to 24 using a filter or the like. Delay time t
1 to t3 can be adjusted by the timing of the trigger signal supplied from the control computer 60 to each solid-state laser device 21 to 24.

The operation of the laser processing apparatus of 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, and each solid-state laser device 21 is output.
Laser beam L11 with appropriate time difference and polarization plane from ~ 24
~ L22 is emitted. The laser beams L11 to L22 are combined by the combining optical system 30 to form two sets of laser beams L1 and L2 which are slightly separated and are translated. Both laser beams L1 and L2
The beam diameter of the beam is expanded as it is through the telescope optical system 40 as it is and the beams are 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 superimposed and incident on the processed surface IS.

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 improved (usually about ± 1% as compared with the case where a gas laser such as an excimer laser is used. Less than). Therefore, the intensity and pulse waveform of the laser beam can be made stable. Further, since the solid-state laser devices 21 to 24 are smaller and cheaper than gas lasers and 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
Laser beams L11 to L22 from 1 to 24 are generated with a predetermined time difference, respectively, and a plurality of generated laser beams L11 to L22 are spatially superposed, so that an arbitrary pulse shape is generated while apparently increasing the laser output. can do. Thereby, the irradiation area on the processed surface IS can be increased to some extent, and the degree of freedom of the process can be increased. Also, the homogenizer 5
Since 0 is used to make the light quantity distribution of the laser beam incident on the processing surface IS uniform, it is possible to perform uniform laser processing of the target region.

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. The light source device can be configured by. In this case, n is a natural number equal to or less than N, the laser beam from the (2n-1) th solid-state laser device is P-polarized, and the laser beam from the (2n) th solid-state laser device is S-polarized. . In the coupling optical system 30, the (2n-1) th and the (2n) th are used by using the n-th one of the N polarization beam splitters constituting the coupling optical system 30.
The pair of laser beams from the th 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, the N sets of laser beams are expanded and bundled, and the homogenizer 5
At 0, the bundled laser beams are decomposed into a large number of secondary light sources, and the laser beams are superposed on the processing surface IS and uniformly incident.

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

The laser processing apparatus of the second embodiment is a modification of the light source apparatus 20 of the first embodiment to obtain a light source apparatus 120 composed of three solid-state laser apparatuses 21, 22, 123. The same parts as those in FIG.

In this case, the light source device 120 includes, in addition to the first and second solid-state laser devices 21 and 22, a third solid-state laser device 123 for generating linearly polarized light having an appropriate polarization plane.
The third solid-state laser device 123 has a 1
A quarter wave plate 129 is provided. As a result, the laser beam L20 entering the coupling optical system 130 is converted from linearly polarized light to circularly polarized light. The laser beam L20 incident on the coupling optical system 130 has its optical path changed through the turn mirrors 31 and 32, and travels in parallel to the laser beam L1 coupled by the polarization beam splitter 34.

In the second embodiment described above, the laser beam L20 from the semi-solid third solid-state laser device 123 which does not form the light source units 21 and 22 for generating random polarization is converted into circular polarization. This is because there is a possibility that a process problem may occur because the absorptance, the reflectivity, and the like differ depending on the polarization direction incident on the processed surface IS. Therefore, if there is no problem even with linearly polarized light in the process, the quarter 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 configured by 2N + 1 (that is, any odd number) 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 Circularly polarized light is made incident on the coupling optical system 130 by the quarter-wave plate 129. [Third Embodiment] FIG. 6 is a view for explaining the structure of a laser processing apparatus according to the third embodiment. The device of the third embodiment is
It is a system incorporating the laser processing apparatus of the first embodiment.

The illustrated laser annealing apparatus has a stage 10 on which a work W, which is a glass plate having a semiconductor thin film of amorphous Si or the like formed on its surface, is placed, and which can be smoothly moved three-dimensionally, and the work W. Light source device 20 having a plurality of solid-state laser devices 21 to 24 for generating a laser beam in the ultraviolet region for heating the semiconductor thin film, and a plurality of laser beams from each solid-state laser device 21 to 24 The optical system 30, the telescope optical system 40 that expands the laser beams that have passed through the coupling optical system 30 and spatially superimposes them, and decomposes the superimposed laser beams into a plurality of laser beams and processes them into a uniform beam of the same size. Homogenizer 50 for superimposing and entering the surface IS
And a position sensor 70 that detects the position of the stage 10 on which the work W is placed, and a stage drive that is a drive unit that appropriately moves the stage 10 with respect to the homogenizer 50 and the like based on the detection result of the position sensor 70. Device 80
And a computer main controller 160 for integrally 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 laser beam LB from the irradiation optical system is applied to the work W.
Make it incident on top. Thereby, 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 stepwise moved in the Y-axis direction each time main scanning is completed, laser annealing of the entire surface of the work W becomes possible. If the homogenizer 50 or the like forms a linear laser beam LB instead of a rectangle, the laser annealing of the entire surface of the work W becomes possible only by moving the stage 10 in the X-axis direction.

When the laser beam LB is scanned, the pulse waveform having a desired distribution with time is formed by adjusting the operation timing of each solid-state laser device 21-24. As a result, the cooling time can be controlled and various needs can be met. The irradiation areas of the pair of continuous laser beams LB may be overlapped by an appropriate amount by appropriately controlling the driving of the stage 10, or may be connected without a gap.

Although the present invention has been described with reference to the embodiments, the present invention is not limited to the above embodiments. For example, in the above embodiment, the half-wave plates 28 and 29 are used.
Although the plane of polarization is rotated by using, the half-wave plates 28 and 29 are unnecessary if the second and fourth solid-state laser devices 22 and 24 themselves are rotated 90 degrees around the optical axis. . 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 of being orthogonal to each other by some method.

In the above embodiment, the wavelength conversion element 2
7 is used to generate ultraviolet light, but if the solid-state laser element 26 that itself generates ultraviolet light 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 processed surface IS, FIG.
As shown in FIG. 5, the solid-state laser devices 21 to 24 can be provided with the elements 21a to 24a for adjusting the optical path lengths, that is, the phases, at the emission ports thereof. Although not shown, also in the case of the second embodiment, an element for adjusting the optical path length can be arranged at the emission port of each solid-state laser device 21, 22, 123. Each element 2
1a to 24a can be simple quartz glass plates, and the speckle pattern can be made inconspicuous by adjusting the mutual phase 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 and semiconductors, but can be applied to various processing such as surface modification of various materials.

[0050]

As is apparent from the above description, according to the laser processing apparatus of the present invention, the stability of laser output can be made relatively high, and space saving and cost reduction can be achieved. it can. Further, it is possible to generate an arbitrary pulse shape while apparently increasing the laser output. In addition, a homogenizer provides more uniform laser
It becomes possible to work. Also here, the expansion of the laser beam and
The superposition keeps the homogenizer relatively small
While achieving sufficient homogenization of the laser beam
It

Further, according to another laser processing apparatus of the present invention, the stability of laser output can be made relatively high, and space saving and cost reduction can be achieved. Further, it is possible to generate a pulse having an apparently increased laser output, and more uniform laser processing becomes possible. Also, here, there is a telescopic
Loop optics keep the homogenization optics relatively small
While achieving sufficient homogenization of the laser beam
It

Further, according to the laser processing method of the present invention, the stability of laser output can be made relatively high, and space saving and cost reduction can be achieved. Further, it is possible to generate an arbitrary pulse shape while apparently increasing the laser output. Further, it is possible to secure the uniformity of the light amount distribution of the laser beam incident on the target surface, and it becomes possible to perform more uniform laser processing. Again here
Uniform by expanding and superimposing the laser beam
Of the laser beam while keeping the optical system relatively small.
Uniformity can be achieved.

[Brief description of 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 a function of a polarization beam splitter that constitutes a coupling optical system.

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

FIG. 4 is a diagram illustrating a composite pulse waveform of a laser beam projected on a processed surface.

FIG. 5 is a diagram illustrating a structure of a laser processing device 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]

10 stages 20 Homogenizer 20 Light source device 21-24 Solid-state laser device 26 Solid-state laser device 27 Wavelength conversion element 28,29 1/2 wave plate 30 Coupled optical system 34 Polarizing beam splitter 40 Telescope optical system 50 homogenizer 60 Control computer

Claims (9)

(57) [Claims] 1. 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 are combined and bundled.
Coupling optical system and a plurality of laser beams that have passed through the coupling optical system are expanded and
Telescope optical system for superimposing a plurality of laser beams
And a uniform beam of approximately the same size.
A laser processing apparatus comprising: a homogenizer for superimposing incident light on a work surface; and a timing adjusting device for adjusting operation timings of the plurality of solid-state laser devices 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 synthetic optical system for superposing a plurality of laser beams from the light source device and making the laser beams incident on a target surface. In the processing device, 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 equal to or less than N and is set to a predetermined polarization plane (2n-1).
The n-th solid-state laser device and the (2n) -th solid-state laser device having a polarization plane different from the predetermined polarization plane are
Th light source unit constitutes a, the combining optical system, and N of the polarization beam splitter for emitting the N sets of the laser beam a pair of laser beams emitted from the light source units bonded to each, the N a polarizing
The N sets of laser beams that have passed through the beam splitter
A telescopic optical system for superimposing the laser beams on each other, and dividing the laser beam obtained by superposing the N sets of laser beams into a plurality of laser beams, and dividing the divided laser beams into uniform beams of substantially the same size on the target surface. A laser processing apparatus, comprising: a homogenizing optical system for superimposing and entering the laser beam. 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 form the light source unit makes a circularly polarized laser beam incident on the combining optical system. The laser processing apparatus according to claim 2. 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 into 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 that changes a polarization plane of a laser beam. . 6. The laser processing apparatus comprises a timing adjusting device that adjusts the operation timing 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 1. 7. The laser according to claim 1, wherein the timing adjustment 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 device according to claim 1, wherein the solid-state laser device is provided with 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 to respectively generate pulsed laser beams from the plurality of solid-state laser devices with a predetermined time difference, and a plurality of laser beams from the plurality of solid-state laser devices.
Combining and bundling ; expanding and spatially superposing the combined and bundled laser beams; and dividing the superposed laser beams into a uniform size having substantially the same size. A laser processing method comprising: a step of superimposing as a beam and making the beam incident on a target surface.