KR101287982B1 - Laser beam machining method and apparatus - Google Patents

Abstract

The present invention relates to a laser processing method and apparatus, and to provide a laser processing method and apparatus capable of efficiently processing a workpiece by improving the utilization efficiency of laser light when performing laser processing by switching a plurality of wavelengths. The purpose.

The present invention is irradiated from the laser oscillator 1 generating the laser beams L ₂ , L ₃ toward the micro mirror array 7 in which a plurality of micro mirrors are regularly arranged and applied to the processing pattern of the workpiece 15. A laser processing method of converting into a modulated light L _M having a corresponding cross-sectional shape and irradiating the workpiece 15 through an irradiation optical system 20 to perform laser processing, wherein the optical axis 20 of the irradiation optical system 20 is The laser beams L ₂ and L ₃ approximately coincide with the direction of diffracted light generated in the micromirror array 7.

Laser light, modulated light, harmonics, diffraction, deflection, irradiation, tilt angle, micromirror, workpiece, processing

Description

Laser processing method and apparatus {LASER BEAM MACHINING METHOD AND APPARATUS}

1 is an explanatory diagram for schematically illustrating a schematic configuration of a laser processing apparatus according to a first embodiment of the present invention.

2 is an optical path explanatory diagram for schematically illustrating an optical path in the vicinity of an active optical element used in a laser processing apparatus according to an embodiment of the present invention.

3 is an angle distribution diagram for explaining the diffraction direction of diffracted light emitted from the active optical element of the laser processing apparatus according to the embodiment of the present invention.

4 is an optical path explanatory diagram for schematically explaining an example of the optical path setting of the laser processing method according to the embodiment of the present invention.

5 is an explanatory diagram for schematically illustrating a laser processing method according to a second embodiment of the present invention.

6 is an explanatory diagram for schematically illustrating a laser processing method according to a third embodiment of the present invention.

7 is an explanatory diagram for schematically illustrating a laser machining method according to a third embodiment of the present invention.

8 is an explanatory diagram for schematically illustrating a laser machining method according to a fourth embodiment of the present invention.

It is an angle distribution diagram for demonstrating an example of the angle distribution of the diffracted light in the laser processing apparatus which can switch a wavelength.

Japanese Patent Application Publication No. 8-174242

 The present invention relates to a laser processing method and apparatus. For example, it is related with the laser processing method and apparatus which remove | eliminate, cut | disconnect, etc. the designated area | region of a to-be-processed object by irradiating a laser beam.

This application claims the priority based on Japanese Patent Application No. 2005-178286 for which it applied on June 17, 2005, and Japanese Patent Application No. 2005-187829 for which it applied on June 28, 2005. The contents are used in the present invention.

Conventionally, the laser processing apparatus which processes by irradiating a laser beam to the desired area | region of a to-be-processed object is known. That is, a laser repair apparatus is known as a means of correct | amending defect parts, such as the wiring pattern on a glass substrate and the unnecessary residue which exists in the photomask used for exposure, at the time of manufacturing a liquid crystal display etc.

Although these laser processing apparatuses prescribed | regulated the magnitude | size of the irradiation area of a laser beam by a variable rectangular opening etc., the apparatus which used spatial modulation elements, such as a micro mirror array, is also known recently.

For example, Japanese Unexamined Patent Application Publication No. 8-174242 (pages 3 to 4, FIGS. 1 to 2) includes a processing table on which a laser source and a workpiece are mounted, and a micro mirror array (micro mirror). And a laser processing apparatus for switching an angle of a plurality of mirror pieces of the micromirror array by ON / OFF control to form an arbitrary pattern shape on a workpiece.

As for the wavelength of the laser used for these laser processing apparatuses, an appropriate wavelength is selected by a process target. For example, in the laser repair apparatus, wavelengths which are easily absorbed by the workpiece, such as visible band to infrared band, and transparent band, are used for the modification of the metal film. In order to switch wavelengths, there exist an apparatus provided with the some laser, the apparatus which can switch the some harmonic of the laser of one fundamental wavelength, etc.

However, in the case of performing laser processing using laser light having a plurality of wavelengths by a laser processing apparatus using an active optical element in which a plurality of active optical elements, such as a micro mirror array, are regularly arranged as in the above-mentioned document, only wavelength Although only changes are made, there is a problem that a phenomenon of lowering the utilization efficiency of laser light occurs.

In the laser processing apparatus using a micro mirror array, the image of a micro mirror array is reduced and projected on a workpiece with a microscope. Since the micro mirror array has a structure in which the small mirrors are arranged at equal intervals, the laser light reflected therefrom is divided into a plurality of diffracted light beams. However, in general, since the numerical aperture behind the microscope is small, it is impossible to enter all the diffracted light divided into a plurality.

Accordingly, a problem may occur in the laser processing apparatus that switches the plurality of wavelengths. This will be described with reference to FIG. 9.

9 is an example of the angular distribution of diffracted light in the laser processing apparatus in which the second harmonic (wavelength lambda ₂ = 532 nm) and the third harmonic (wavelength lambda ₃ = 354.7 nm) of the YAG laser are switched. That is, the angle distributions α and β of the diffracted light reflected by the micromirror array are plotted on the angular plane 501 around the optical axis 502 of the incident microscope.

At the wavelength λ _3, there is one diffraction order 504 near the optical axis 502, as indicated by the X table in the figure. Since the small mirror corresponding to the irradiation area of the laser light is inclined so as to reflect the laser light in the direction of the optical axis 502, the diffraction order 504 close to the optical axis 502 is the only diffraction light having a large intensity. Since the diffraction order 504 is within the range of the rear side opening 503 of the microscope, it is possible to effectively irradiate the workpiece with the intensity of the laser light.

On the other hand, when the wavelength is switched to λ ₂ , as shown by the circle shown in the figure, there are no diffraction orders near the optical axis 50, and four diffraction orders 505 exist at positions separated by the same angle. Therefore, the intensity of the laser is dispersed in the plurality of diffraction orders 505, and the incident light does not enter the rear angle opening 503 of the microscope. It is possible to enter one diffraction order by changing the square with respect to the microscope, but this does not improve the utilization efficiency of the laser light.

MEANS TO SOLVE THE PROBLEM This invention can improve the utilization efficiency of a laser beam, and can process a to-be-processed object efficiently by performing a laser processing by switching a several wavelength by solving the above-mentioned subject. The purpose is to provide.

In order to solve the said subject, the laser processing method of this invention irradiates the said laser beam from the laser light source which generate | occur | produces the laser beam which has a some wavelength toward the active optical element in which the some active optical element was regularly arranged. And converting the laser light into a modulated light having a cross-sectional shape corresponding to the processing pattern of the workpiece, and irradiating the workpiece with a modulated light irradiation optical system to perform laser processing. The direction of the diffracted light of the plurality of wavelengths generated in the active optical element by the laser light having two wavelengths is substantially coincident with the direction of the optical axis of the modulated light irradiation optical system.

According to the present invention, even when the wavelength of the laser light is switched, the modulated light is reflected in the direction along one diffraction direction and enters the modulated light irradiation optical system. Therefore, even if the wavelength is switched, it is possible to irradiate the workpiece with laser light having good use efficiency.

In the laser processing method of the present invention, the optical axis of the modulated light irradiation optical system is substantially common among the diffraction directions of the diffracted light generated in the active optical element by the respective laser beams having the plurality of wavelengths. You may make it substantially correspond to a direction.

Moreover, in the laser processing method of this invention, it is preferable to form the laser beam which has the said some wavelength from several harmonics by one laser light source.

In this case, the plurality of harmonics of one laser light source have diffraction directions that are completely common to the respective wavelengths because each wavelength is related to the integer ratio. Therefore, the utilization efficiency at the time of wavelength conversion can be improved.

Moreover, in the laser processing method of this invention, it is preferable to form the laser beam which has the said some wavelength by the some laser light source from which a wavelength differs.

In this case, since the optimum wavelength can be set according to the wavelength absorption characteristic of the workpiece, the processing efficiency can be improved.

Moreover, in the laser processing method of this invention, it is preferable that the said active optical element is a micromirror array provided with the some small mirror in which the inclination angle was switchable as said plurality of active optical elements.

In addition, in the laser processing method provided with the micromirror array of this invention, in the on state which reflects the said laser beam as said modulated light, the inclination angle of the said small mirror has the said modulated light in the optical axis direction of the said modulated light irradiation optical system. It is desirable to set it to reflect

In this case, since the direction in which the modulated light is reflected coincides with the optical axis direction of the modulated light irradiation optical system, it coincides with a substantially common diffraction direction which is a plurality of wavelengths. Therefore, since the specular reflection direction by the small mirror and the diffraction direction coincide, the utilization efficiency of modulated light can be improved.

Further, in the laser processing method of forming a laser beam having a plurality of wavelengths of the present invention from a plurality of harmonics by one laser light source, the plurality of harmonics are n (n ≧ 2) u's. _k harmonics when La (u _k are mutually different integers, k = 1, 2, ··· , n), as the diffraction direction common to the plurality of wavelengths, each of the diffraction orders of the plurality of harmonics, (u _k M _x , u _k · m _y ), where m _x and m _y are integers.

In this case, since the optical axis of the modulated light irradiation optical system is aligned with the direction of the diffraction orders of (u _k · m _x , u _k · m _y ), the diffraction direction of the laser light formed from a plurality of harmonics by one laser light source Can match exactly.

In the laser processing method of forming a laser light having a plurality of wavelengths of the present invention by a plurality of laser light sources having different wavelengths, the wavelengths of the plurality of laser light sources are n (n? 2) lambda u _k (u). _k is an integer different from each other, k = 1, 2, ..., n), and as a diffraction direction common to the plurality of wavelengths when λu _k is approximately (λ / u _k ) for a constant wavelength λ It is preferable that the diffraction orders of the laser beams having the plurality of wavelengths are set in a direction in which (u _k · m _x , u _k · m _y ) differences (where m _x and m _y are integers).

An optical axis of in this case, the modulated light irradiation optical system, for a certain wavelength λ, λu when _k is one approximately (λ / u _k), (u _k · m _x, u _k · m _y) direction of the diffraction order of the car Therefore, the direction of diffraction of the laser beams formed by the plurality of laser light sources having different wavelengths can be approximately coincident with each other.

In the laser processing apparatus of the present invention, a laser light source for generating laser light having a plurality of wavelengths and a plurality of active optical elements are regularly arranged so that the laser light is modulated light having a cross-sectional shape corresponding to the processing pattern of the workpiece. A laser processing apparatus comprising: an active optical element for converting; and a modulated light irradiation optical system for irradiating the workpiece with the modulated light; a diffraction of a plurality of wavelengths generated in the active optical element by the laser light having the plurality of wavelengths. The direction of the light is substantially coincident with the direction of the optical axis of the modulated light irradiation optical system.

According to this invention, it becomes a preferable apparatus for performing the laser processing method of this invention. Therefore, it has the same effect | action and effect as the laser processing method of this invention.

In the laser processing apparatus of the present invention, a direction in which an optical axis of the modulated light irradiation optical system is substantially common to the plurality of wavelengths among diffraction directions of diffracted light generated in the active optical element by each laser beam having the plurality of wavelengths. It may roughly match with.

Moreover, in the laser processing apparatus of this invention, the said active optical element consists of a micromirror array provided with the some micromirror which deflects the said laser beam by switching the inclination angle as said plurality of active optical elements, The said micro It is preferable that the inclination angle of the mirror is set to the angle which reflects the said laser beam to the optical axis direction of the said modulated light irradiation optical system.

In addition, since the direction in which the modulated light is reflected coincides with the optical axis direction of the modulated light irradiation optical system, the direction in which the modulated light is reflected coincides with the diffraction direction substantially common to the plurality of wavelengths. Therefore, since the specular reflection direction by the small mirror and the diffraction direction substantially coincide, the utilization efficiency of modulated light can be improved.

The laser processing apparatus of the present invention includes a spatial modulation element in which a plurality of deflection elements capable of deflecting laser light generated by a laser light source in at least two directions are regularly arranged, and the laser light source and the space for the modulated light irradiation optical system. A rotating mechanism capable of changing the inclination of at least one of the modulation elements, wherein the modulated light irradiation optical system is configured to receive the modulated light deflected in one of the at least two directions by the spatial modulation element. Irradiating to the said rotation mechanism, the said rotation mechanism may make the emission angle with respect to the said spatial modulation element of the said modulated light advancing along the optical axis of the said modulated light irradiation optical system variable.

According to this configuration, the tilting mechanism of at least one of the laser light source and the spatial modulation element can be varied with respect to the modulated light irradiation optical system by the rotation mechanism, and accordingly, the spatial modulation of the modulated light propagated along the optical axis of the modulated light irradiation optical system. You can change the exit angle for the device. Thus, even if the modulated light is diffracted by the spatial modulator, the modulated light traveling along the optical axis of the modulated light irradiation optical system can be matched to the one in the appropriate diffraction direction. Therefore, light having high diffraction efficiency as the modulated light can be incident on the modulated light irradiation optical system.

Moreover, in the laser processing apparatus of this invention, it is preferable to set it as the structure which the said rotation mechanism rotates so that the inclination of the said laser light source with respect to the said space modulation element may be changed.

In this case, since the inclination of the laser light source can be changed with respect to the spatial modulation element by the rotation mechanism, the incident angle of the laser light with respect to the spatial modulation element can be changed when the spatial modulation element is fixed. Therefore, the modulated light traveling along the optical axis of the modulated light irradiation optical system can be matched to the diffracted light of the appropriate order in accordance with the wavelength of the laser light and the incident angle incident on the spatial modulation element. Thus, modulated light having high diffraction efficiency can be incident on the modulated light irradiation optical system.

Moreover, in the laser processing apparatus of this invention, it is preferable to set it as the structure which rotates so that the inclination of the said space modulation element with respect to the said modulated light irradiation optical system may be changed.

In this case, since the exit angle of the modulated light incident on the modulated light irradiation optical system with respect to the spatial modulation element can be changed, it is possible to match the diffracted light of an appropriate order according to the wavelength of the laser light and the incident angle incident on the spatial modulator. Therefore, it is possible to enter modulated light having high diffraction efficiency into the modulated light irradiation optical system.

In addition to such a configuration, when the rotation mechanism is configured to rotate so as to change the inclination of the laser light source with respect to the spatial modulation element, the combination of these rotations optimizes the diffraction conditions of the modulated light incident on the modulated light irradiation optical system. can do.

In addition, if the laser light source can be rotated in accordance with the rotation of the spatial modulation element, the output angle of the modulated light can be changed under a condition in which the incident angle of the laser light is constant, so that the rotation control becomes easy and the diffraction order of the modulated light can be changed efficiently. .

Further, in the laser processing apparatus of the present invention, a diffraction direction of the modulated light is calculated from the rotational position of the tilting mechanism and the wavelength of the laser light, and the tilting mechanism is adjusted so that the diffraction direction coincides with the optical axis of the modulated light irradiation optical system. It is preferable to have a rotating mechanism control part for driving.

In this case, since the diffraction direction of the modulated light can be calculated by the tilting mechanism control unit and the optical axis of the modulated light irradiation optical system can be matched, the diffraction efficiency can be automatically optimized.

Moreover, in the laser processing apparatus provided with the said rotation mechanism control part of this invention, the said laser light source generate | occur | produces so that switching of the laser beam of 2 or more different wavelengths is possible, and it is common that the said rotation mechanism control part is a wavelength of each said laser beam. It is preferable to match the optical axis of the modulated light irradiation optical system, which is a diffraction direction.

In this case, when performing laser processing using a laser beam having a plurality of wavelengths, since the diffraction efficiency of the modulated light can be optimized without adjusting the rotation mechanism even if the wavelength is switched, the laser processing with the wavelength switched Can be performed quickly, and the processing efficiency can be improved.

In the laser processing apparatus of the present invention, the spatial modulation element is configured as a plurality of micromirror arrays including a plurality of micromirrors that deflect the laser light in at least two directions by switching the inclination angle as the plurality of deflection elements. desirable.

In this case, in order to improve the diffraction efficiency of the modulated light, the diffraction direction of the modulated light is made to coincide with the optical axis of the modulated light irradiation optical system by the rotating mechanism, so that even when the inclination angle of the micromirror takes a constant value, the diffraction efficiency of the modulated light is easy. It can be optimized so that high speed and high efficiency laser processing can be performed.

  EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described with reference to an accompanying drawing. In all the drawings, even when the embodiments are different, the same or similar members are given the same reference numerals, and common descriptions are omitted.

[First Embodiment]

A laser processing apparatus according to a first embodiment of the present invention will be described.

The laser processing apparatus of this embodiment 100, also with a wavelength of λ _2, λ ₃ of the laser beam L _2, the L _3,, as a modulated light L _M the workpiece (15 according to the processing pattern, respectively, as shown in Figure 1 ) Is a device that performs laser processing by irradiating onto the image.

As the to-be-processed object 15, the glass substrate used for a liquid crystal display etc., a semiconductor substrate, etc. are mentioned, for example. In these cases, the processing object may include a defective part such as an unnecessary residue present in a wiring pattern on a substrate or a photomask used for exposure.

Although the workpiece 15 is not specifically shown, it is hold | maintained in the mounting base provided with the holding mechanism which fixes the position at the time of a process, the adsorption mechanism, and the moving mechanism for the movement of a processing position as needed, for example. . Moreover, when using for a micro die section apparatus, biological samples, such as a cell, etc. are mentioned.

The laser beams L ₂ and L ₃ are switched and divided according to the wavelength absorption characteristics of the processing target.

The schematic configuration of the laser processing apparatus 100 includes a laser oscillator 1 (laser light source), a plane mirror 6, a micro mirror array 7 (active optical element), an irradiation optical system 20 (modulated light irradiation optical system) , And the controller 16.

The laser oscillator 1 is a laser light source for processing pulse oscillation. In this embodiment, a YAG laser having a fundamental wavelength λ ₁ = 1.064 μm is used, and the second and third harmonics (wavelength λ ₂ = 532 nm and λ ₃ = 354.7 nm, respectively) are switched by switching harmonic crystals inside. Each of the laser beams L ₂ and L ₃ can be emitted on the same optical path.

The beam diameters of the laser beams L ₂ and L ₃ are set to a size that can sufficiently cover the reference reflecting surface 7a of the micromirror array 7 described later. Therefore, although not shown in particular, the laser oscillator 1 is suitably equipped with the optical system, such as a beam expander, a stop which regulates a beam diameter, etc. as needed.

Transmitted through the optical attenuator 3 and the laser light L ₂ (L ₃₎ for adjusting the light amount of the laser oscillator (1) the laser beam L ₂ On the optical path of the (L _3), the laser beam L ₂ (L ₃₎ exiting from the They are arranged in the order of half tugyeong 4 and the plane mirror 6 to guide the illumination light reflected by the illuminating light Lm Lm emitted from the visible light source 5 to the laser beam L ₂ (L ₃₎ with the same optical path.

As the semi-transmissive mirror 4, any optical path branching element having such a reflectance characteristic can be used. For example, a half mirror, a beam splitter, a dichroic mirror, or the like can be adopted.

The plane mirror 6 is a deflection element which deflects the laser light L ₂ (L ₃ ) and enters the micro mirror array 7 at a constant incidence angle.

As shown in FIG. 2, the micromirror array 7 includes a plurality of small mirrors that are aligned on the reference reflecting surface 7a when the inclination angle is 0 ° and that are inclined in a predetermined direction as a control signal. 7b) (active optical element, deflection element) are arranged regularly in a plurality, longitudinal and horizontal lattice shapes, and the like. For example, a device such as a DMD (Digital Micro-mirror Device) in which 800 x 600,000 small mirrors 7b of 16 mu m angles are arranged in a rectangular area can be employed.

Each of the small mirrors 7b can be inclined at an appropriate inclination angle by a driver (not shown) that generates an electrostatic field in accordance with the control signal. Hereinafter, an example of inclining at two inclination angles of an on state and an off state will be described. Two inclination angles of an on state and an off state are +/- 12 degrees, for example.

Therefore, the micromirror array 7 reflects the laser light L ₂ (L ₃ ) incident at a constant incidence angle by the small mirror 7b in the on state to form a modulated light L _M having a cross-sectional shape according to the control signal. Spatial reflection of the laser beam L ₂ (L ₃ ) can be performed by reflecting the light reflected by the off-sized mirror 7b to an optical path different from the optical path of the modulated light L _M (see L _F in FIG. 1). It is.

For example, in FIG. 2, the small mirror 7b in which the small mirror 7b is inclined by the inclination angle phi _{ON in the} counterclockwise direction from the reference reflecting surface 7a is shown. The code | symbol N represents the normal line of the reference reflection surface 7a. The laser light L ₂ (L ₃ ) incident on the reference reflective surface 7a at an angle θ _i is reflected by the small mirror 7b and is reflected in the regular reflection direction R. However, in order to make it easy to see, FIG. 2 has shown even if it is the same angle.

On the other hand, the plurality of small mirrors 7b arranged at such equal pitch and inclined in the same direction act as diffraction gratings for the laser light L ₂ (L ₃ ). Therefore, the laser beam L ₂ (L ₃ ) is diffracted in accordance with the wavelength and the arrangement pitch of the small mirror 7b.

Therefore, the intensity of light in each diffraction direction corresponding to the diffraction order becomes strong, and in the direction therebetween, the diffraction efficiency decreases and the light intensity decreases. In FIG. 2, the diffraction direction D inclined by the angle θd from the normal line N illustrates the diffraction direction common to the laser beam L ₂ (L ₃ ) among these diffraction directions.

In FIG. 3, the angular distribution of the diffracted light reflected by the micromirror array 7 is plotted on the angular plane 201 as the angular groups α and β in two directions. The circle represents the diffraction direction of the laser light L ₂ of the wavelength λ ₂ , and the x mark represents the diffraction direction of the laser light L ₃ of the wavelength λ ₃ , respectively.

Further, since the laser beam L ₂ (L _3), the harmonic of the fundamental wavelength λ _1, the wavelength λ _2, the ratio of λ _3, exact integer ratio 3: is a 2. Thus, m _x, when integers of m _y, laser light diffraction order of _{L 2 (2 · m x,} 2 · m y) order, the diffraction order of laser light _{L 3 (3 · m x,} 3 · m y) difference The respective diffraction directions of are identical.

Here, the setting method of the optical path in the laser processing method which concerns on a present Example is demonstrated. However, for the sake of simplicity, explanation will be made using the one-dimensional diffraction model shown in FIG. 4.

4 is a schematic view of an optical path by a one-dimensional model for setting an optical path of the laser processing method according to the present embodiment.

When incident on the micromirror array 601 at the incident angle θ _i as the fundamental wave, the second harmonic wave, the third harmonic wave, and the incident light 602 of the YAG laser, the diffraction angle θ _d of each gray light is the diffraction condition of the following equation. It is represented by.

sinθ _d -sinθ _i = p · λ _i / T (1)

Where p is the diffraction order, lambda _i is the wavelength of the incident light 602, and T is the array pitch of the micromirror array 601. FIG.

It is assumed that the diffraction angles of the zeroth order diffracted light 610 and the first order diffracted light 611 of the fundamental wave of the YAG laser are as shown in FIG. At this time, the direction of the zeroth order diffracted light 620 of the second harmonic coincides with the zeroth order diffracted light 610 of the fundamental wave. The direction of the second diffracted light 622 of the second harmonic coincides with the first diffracted light 611 of the fundamental wave. Between them are the first harmonic primary diffracted light 621. Similarly with the third harmonic, the directions of the zeroth order diffracted light 630 and the third order diffracted light 633 coincide with the zeroth order diffracted light 610 and the first order diffracted light 611 of the fundamental wave, respectively, and the middle of both sides. Are primary diffracted light 631 and secondary diffracted light 632. This property is evident by the diffraction conditions of equation (1).

That is, the zeroth order diffracted light 610, 620, 630 of the fundamental wave, the second harmonic wave, and the third harmonic wave is the case of p = 0 in the formula (1), and is the micromirror of the micromirror array 601. Is the specularly reflected light when aligned with the reference reflective surface.

When p is not O, the condition which diffraction angle (theta) _d becomes the same is that p * (lambda) _i becomes constant according to Formula (1).

_{λ 2 = λ 1/2,} λ 3 = Because the λ _1/3, 4, is that the first-order diffracted light (611) (p = 1) and the diffraction direction of the wavelength λ ₁ match, and the wavelength λ _In the second harmonic of 2, it is the secondary diffracted light 622 (p = 2), and in the third harmonic of the wavelength lambda _{3, it} is the third diffracted light 633 (p = 3). In general, in the diffraction direction of the mth diffracted light of the fundamental wavelength, the diffraction direction of the (u · m) th diffracted light of the uth harmonic coincides.

Therefore, the first diffracted light 621 of the second harmonic, the first diffracted light 631 of the third harmonic, and the second diffracted light 632 are diffracted in different diffraction directions, respectively.

For example, when the array pitch of the small mirror of the micromirror array 601 enters the second harmonic (wavelength 532 nm) at the incident angle θ _i = 36.8 ° when T = 16 μm, 18 (= 2 × 9) The diffraction angle of the diffracted light is θd = 0 °. When the third harmonic (wavelength 354.7 nm) is incident at the same incidence angle θ _i , the diffraction angle of the 27 (= 3 × 9) order diffracted light becomes θ d = 0 °, and both sides coincide.

If the inclination angle of the small mirror of the micromirror array 601 is set to half (18.4 °) of the incidence angle, the reflected light from each of the small mirrors is concentrated in the diffraction orders having the common diffraction angle, so that their diffraction efficiency is maximum. Becomes Therefore, even if the wavelength of the YAG laser is switched, the incident conditions to the optical system after the micromirror array 601 do not change, and the utilization efficiency of the laser light amount can be maximized.

These diffraction conditions can be easily extended to a two-dimensional micro mirror array.

Such a diffraction direction can be set similarly even if the number of harmonics increases. That is, when a plurality of harmonics are n (n? 2) u _th harmonics (u _k is a different integer from each other, k = 1, 2, ..., n), they are common to the plurality of wavelengths. What is necessary is just to set it as a direction in which a diffraction order is a (u _k * m _x , u _k * m _y ) difference (where m _x . M _y is an integer) as the diffraction direction.

In this embodiment, As shown, the diffraction order of laser light _{L 2, L 3 (2 O4} , 205) in Figure 3, corresponds to the diffraction direction (αo, βo). Therefore, the optical axis 202 of the irradiation optical system 20 is set to coincide with these diffraction directions, and the inclination angle of the small mirror 7b is set by the control signal so that the specular reflection directions of the optical axis 202 and the small mirror 7b coincide with each other. Set it.

As a result, the intensity of the diffraction orders 204 and 205 of each wavelength uniquely present in the rear angle opening 203 of the irradiation optical system 20 becomes maximum, and the intensity of the other diffracted light becomes extremely small. And, even when the wavelength is switched to a different laser light L _2, L _3, respectively, are incident under the same conditions as for the irradiation optical system 20 is maintained.

The diffraction directions αo and βo do not have to coincide with the normal line N of the reference reflection surface 7a, but the reference reflection surface 7a is within a range of the depth of field of the irradiation optical system 20. desirable.

Referring back to FIG. 1, the irradiation optical system 20 is composed of an imaging lens 11 and an objective lens 14 arranged on the same axis, and the optical axis 202 is diffracted by the micromirror array 7. It is an imaging optical system which coincides with (alpha) o, (beta) o, and is provided so that the reference | standard reflection surface 7a and the to-be-processed object 15 may be substantially conjugated. For example, an optical system such as a microscope can be employed.

The objective lens 14 has an infinite design on the image side, and the laser light L ₂ (L ₃ ) is substantially parallel light between the imaging lens 11 and the objective lens 14.

On an optical path of substantially parallel light, a semi-transmissive mirror 12 is formed which reflects a part of the illumination light L _ob emitted from the visible light source 13, transmits a part thereof, and transmits the modulated light L _M. Therefore, the illumination light L _ob is guided onto the same optical path as the modulated light L _M , so that the workpiece 15 can be illuminated.

The wavelength of illumination light L _ob may be any wavelength as long as it can be imaged by CCD10 mentioned later, and can be set to the wavelength range of visible light, for example.

The translucent mirror 12 may employ, for example, an optical splitter such as a reflector, a prism, or the like having a half mirror or a coating having such wavelength characteristics.

In the optical path between the imaging lens 11 and the micromirror array 7, a translucent mirror 8 is formed which transmits the modulated light L _M and reflects the illumination light L _ob reflected from the workpiece 15. . Therefore, when the illumination light L _ob is reflected by the workpiece 15 and returns to the translucent mirror 8, the optical path is branched. The translucent mirror 8 can adopt the same structure as the translucent mirror 12.

On the optical path branched by the translucent mirror 8, the CCD 10 for picking up the image on the workpiece 15 is disposed at a position substantially spaced with the surface of the workpiece 15.

 The control part 16 controls the whole laser processing apparatus 100, and transmits it from the operation input from the operation part 17, CCD 10, and operation part 17, and the CCD 10 to perform operation input. The monitor 9 for displaying the image signal to be connected is connected.

Moreover, at least it is electrically connected with the laser oscillator 1 and the micromirror array 7 which are control objects, and can transmit the control signal which controls those operations with respect to each.

That is, the laser oscillator 1 transmits a control signal for selecting one of the laser beams L ₂ and L ₃ to turn on or off based on the operation input of the operation unit 17.

Further, with respect to the micro mirror array 7, reads an image of the workpiece 15 captured by the CCD (10) and, by detecting the area to be processed by the image processing and processing the irradiated region of the modulated light L _M A control signal for controlling the on state and the off state of each small mirror 7b is sent so as to match the area to be made.

Next, the operation of the laser processing apparatus 100 according to the present embodiment will be described.

First, using the laser processing apparatus 100, the processing pattern data for laser processing is created. Therefore, the illumination light L _ob is emitted from the visible light source 13, reflected from the translucent mirror 12, and illuminates the workpiece 15 through the objective lens 14.

The reflected light of the illumination light L _ob passes through the objective lens 14, the translucent mirror 12, and the imaging lens 11, respectively, is reflected by the translucent mirror 8, and is captured by the CCD 10. And the image of the surface of the to-be-processed object 15 by illumination light L _ob is sent to the control part 16 as an image signal 150A.

The control unit 16 converts the image signal 150A into image data and displays it on the monitor 9.

And the operator observes the image of the monitor 9, designates the defect part or cut part which should be processed through the operation part 17, or image-processes the image data by the control part 16, and automatically extracts a defect part or cut part, and those defects The processing pattern data 151 corresponding to the image data of the part and the cut part is created.

The processing pattern data 151 is control data for causing the laser beam irradiation region to correspond to the on state of each of the small mirrors 7b of the micromirror array 7.

Next, in order to verify the processing pattern data 151, the visible light source 5 is turned on, and the illumination light L _m is irradiated to the reference reflecting surface 7a through the translucent mirror 4 and the plane mirror 6. Then, the processing pattern data 151 is sent to the micro mirror array 7. Then, the reflection light of the illumination light L _m by a small mirror (7b) in the on state, through the image forming lens 11, the objective lens 14, is guided onto the work piece (15). The reflected light is reflected by the translucent mirror 8 through the same optical path as the reflected light by the illumination light L _ob radiated from the visible light source 13, and is captured by the CCD 10. This pixel is sent to the control unit 16 as an image signal 150B.

The control unit 16 displays the image data based on the image signal 150B on the monitor 9 by superimposing the image data based on the image signal 150A with brightness, color, and the like so as to be distinguishable.

The operator instructs the correction through the operation unit 17 when determining that it is necessary to correct the processing pattern data 151 from the display image of the monitor 9. After the end of the modification, the above operation is repeated.

When it is determined that there is no need for correction, the wavelength used for laser processing, for example, [lambda] ₂ is selected, the operation input which instruct | indicates a processing start is performed, and a laser processing process is started.

In the laser processing step, the control unit 16 transmits a control signal for oscillating the laser light L ₂ to the laser oscillator 1, and simultaneously transmits the processing pattern data 151 to the micromirror array 7.

The laser beam L ₂ is the intensity of light is adjusted by the optical attenuator (3), half tugyeong (4) passes through the, is deflected by the plane mirror 6, a reference reflecting surface (7a) of the micro-mirror array 7 Is incident at a constant incidence angle θ _i .

A micro mirror array (7), each small mirror (7b) the processing pattern data 151 is the ON state and so the off state is controlled tilt angle, the laser light L ₂ of, compact mirrors (7b) of the on-state in accordance with the Only the incident portion is reflected as the modulated light L _M in the normal reflection direction R, and transmits the translucent mirror 8. Then, the light enters the imaging lens 11 along the optical axis 202, and is imaged on the workpiece 15 by the objective lens 14.

Then, the modulated light L _M is irradiated to the region corresponding to the processing pattern data 151 on the work piece (15). Therefore, the area corresponding to the processing pattern data 151 is radar processed by the modulated light L _M.

At this time, the modulated light L _M is diffracted by the micromirror array 7, but in this embodiment, since the diffraction direction corresponding to the diffraction order 204 and the regular reflection direction R coincide, the diffraction efficiency is maximum. Is incident in the rear angle opening 203 of the irradiation optical system 20.

Therefore, the utilization efficiency of laser light can be improved.

In this way, in the laser processing apparatus 100, the processing pattern of the area | region to be laser-processed is created from the image of the to-be-processed object 15, and the area | region which matches the processing pattern is processed by irradiating one shot of laser beam. Can be.

Then, from the operation unit 17, an operation input for switching the wavelength of the laser light used for processing is performed, and the control unit 16 sends a control signal for switching the wavelength of the laser light to the laser oscillator 1, thereby producing a wavelength. It can switch and perform laser processing. For example, instead of laser light L ₂ , laser light L ₃ is selected, and a laser processing process can be performed in the same manner as above.

At this time, since the laser light L ₃ has a different wavelength, it is diffracted in a diffraction pattern different from the laser light L ₂ by the micromirror array 7, but the diffraction direction corresponding to the diffraction order 205 of the laser light L ₃ is Since it is common with the diffraction direction of the diffraction order 204 of the laser beam L ₂ , the diffraction efficiency also becomes maximum even in the case of the laser beam L ₃ . That is, even when such wavelength conversion is performed, the utilization efficiency of a laser beam is maintained favorable.

Therefore, the wavelength conversion can be performed easily and quickly without the trouble of adjusting the inclination angle of the small mirror 7b or changing the angle of incidence to the micromirror array 7 by the wavelength so that the utilization efficiency does not deteriorate even during the wavelength conversion. Can be done.

[Second Embodiment]

A laser processing apparatus according to a second embodiment of the present invention will be described.

In FIG. 5, the schematic structure of the laser processing apparatus 110 which concerns on 2nd Example of this invention is demonstrated typically.

As shown in FIG. 5, the laser processing apparatus 110 of this embodiment is provided with the laser light source 130 instead of the laser oscillator 1 of the laser processing apparatus 100 which concerns on 1st Embodiment of this invention. . The following description will focus on the points different from the first embodiment.

The laser light source 130 is a laser light source capable of pulse oscillating laser lights L _A and L _B (wavelengths λ _A and λ _B , respectively) of different wavelengths and emitting the same light path as substantially parallel light beams. The schematic configuration consists of the laser oscillators 1A and 1B and the dichroic mirror 2.

The beam diameters of the laser beams L _A and L _B are such that they can sufficiently cover the reference reflecting surface 7a of the micromirror array 7. Therefore, although not particularly illustrated, the laser oscillator 130 is appropriately provided with an optical system such as a beam expander, an aperture for regulating the diameter of the light beam, and the like, as necessary.

For example, as the laser oscillator 1A, a nitrogen laser (wavelength λ _A = 337.1 nm) and the laser oscillator 1B can employ a YAG laser that outputs second harmonics (λ _B = 532 nm). In this case, the ratio of the two wavelengths, λ _A : λ _B, is approximately an integer ratio 5: 8.

The control section 16 is connected to the laser oscillators 1A and 1B, respectively, and the respective selection switching, lighting, turning off, oscillation and the like are performed by the control signal of the control section 16.

Dichroic mirror 2 into a dyke is provided for synthesizing the optical paths of the laser light L _A, L _B, in this embodiment, and substantially passes through the laser light L _A, has the wavelength characteristic which substantially reflects the laser light L _B .

In this embodiment, since the wavelength ratio of the laser lights L _A and L _B is approximately 5: 8, similarly to the first embodiment, the diffraction order of the laser light L _A is defined as m _x and m _y as integers. _x, 8 m · _y), the diffraction direction and diffraction order of laser light L _B of the car _{(5 · m x · 5 ·} m y) and the diffraction direction of a car, substantially match. Thus, the optical axis 202 of the irradiation optical system 20 is disposed so as to substantially coincide with these diffraction directions. And the inclination angle of the small mirror 7b is set so that the normal reflection direction of the optical axis 202 and the small mirror 7b may correspond.

Therefore, even when the laser beams L _A and L _B are switched and irradiated, the incident conditions to the irradiating optical system 20 do not change, and each of them is incident at the highest diffraction efficiency.

When a laser machining process using a laser processing apparatus (11O) includes: a first embodiment of the laser light L _2, L _3, simply replaced with the laser light L _A, L _B, it is performed similarly.

Therefore, laser processing can be performed efficiently even if a wavelength is switched.

In this embodiment, the degree of constant ratio of the wavelength ratio is set by the degree of agreement of the diffraction directions to be matched. For example, when m _x and m _y become large, the diffraction direction is shifted in proportion to the shift of the integer ratio, and therefore, it is preferable to approach a more exact integer ratio. On the other hand, when m _x and m _y are relatively small, even if they deviate from a strict integer ratio, the amount of shift | offset | difference in a diffraction direction becomes small and favorable diffraction efficiency can be obtained.

It is preferable to set the shift amount in the diffraction direction to be smaller than at least the rear angle opening of the irradiation optical system 20.

In the present embodiment, an example in which two laser oscillators 1A and 1B are used as the laser light source has been described, but three or more laser oscillators are used, or a combination of multi oscillation lasers is used to switch the laser light of three wavelengths or more. It can be modified.

In this case, the wavelength of the plurality of laser light sources is n (n> 3) lambda _uk (u _k is an integer different from each other, k = 1, 2, ..., n), and for a constant wavelength lambda, When λ _uk is approximately (λ / u _k ), as a diffraction direction common to each wavelength of light, the diffraction orders are (u _k · m _x , u _k · m _y ) differences (where, m _x , m _y) Is set in the diffraction direction of an integer).

The second embodiment corresponds to the case where n = 2 in the above relation.

In the above description, an example is described in which the diffraction direction in which the plurality of wavelengths coincide with the regular reflection direction in the on state of the small mirror 7b of the micromirror array 7 coincides. If the degree of efficiency is within the allowable range, the diffraction direction and the normal reflection direction may be shifted. In other words, the diffraction direction and the specular reflection direction do not need to be completely coincident, and may be substantially coincident in the range in which the desired laser processing is possible.

For example, the micromirror array 7 may have a configuration in which the diffraction direction and the regular reflection direction are slightly shifted by using the inclination angle of the standard product. In this case, since the inclination angle of the small mirror 7b does not need to be set exclusively, there is an advantage that it is possible to employ the inexpensive micromirror array 7.

Moreover, it is preferable to set it as the structure in which only the diffraction light of one order of a some wavelength injects into a rear angle opening of a microscope. At this time, the image of the micromirror array projected onto the workpiece is not resolved by the images of one small mirror. However, due to the gap between the small mirrors, it is possible to prevent the occurrence of lattice-shaped non-uniform processing state.

Moreover, in the above description, since the laser beam is incident on the micromirror array 7 at a predetermined angle, the case of deflection in the plane mirror 6 has been described. However, when the laser beam can be incident at a predetermined angle directly from the laser light source, The plane mirror 6 may be omitted.

In the above description of the first embodiment, an example in which two of the second and third harmonics are used as the harmonics has been described, but three or more harmonics may be used as necessary. In addition, you may select the order of harmonics at random.

In the above description, an example in which a micro mirror array made of DMD is used as the active optical element has been described, but the active optical element is not limited thereto.

The same applies to the case where other reflective active optical elements or the like which are affected by diffraction by the arrangement pitch of the active optical elements are used.

Third Embodiment

Next, a laser processing apparatus according to a third embodiment of the present invention will be described.

6 is a diagram for schematically illustrating a schematic configuration of a laser processing apparatus 200 according to a third embodiment of the present invention.

As shown in this embodiment the laser processing apparatus 200, Fig. 6, the laser light L _2, L ₃ is the wavelength of λ _2, λ _3, respectively, as modulation light L _M, according to the processing pattern workpiece ( 15) It is an apparatus which performs laser processing by irradiating on.

The laser lights L ₂ and L ₃ are switched according to the wavelength absorption characteristics of the workpiece 15 and can be used separately.

The schematic configuration of the laser processing apparatus 200 includes the laser oscillator 1 (laser light source), the tilt stage 104 (rotating mechanism), the micro mirror array 7 (space modulation element, active optical element), and the tilt It consists of the stage 105 (rotating mechanism), the irradiation optical system 20 (modulated light irradiation optical system), and the control part 16. As shown in FIG.

The laser oscillator 1 is a laser light source which pulses a laser beam having a plurality of wavelengths and emits it as a substantially parallel light beam. In this embodiment, using a YAG laser having a fundamental wavelength lambda ₁ = 1.064 mu m, the second and third harmonics (wavelength lambda ₂ = 532 nm and lambda ₃ = 354.7 nm, respectively) are switched, and the laser lights L ₂ and L, respectively. _{As 3} , it is possible to emit on the same optical path.

The beam diameters of the laser beams L ₂ and L ₃ are sized to sufficiently cover the reference reflecting surface 7a of the micromirror array 7 described later. Therefore, although not shown in particular, the laser oscillator 1 is equipped with the optical system, such as a beam expander, a stop which restricts a beam diameter, etc. suitably as needed.

The inclination stage 104 is a rotation mechanism for rotatably supporting the laser oscillator 1 around the rotation center 104C provided on the optical axes of the laser beams L ₂ , L ₃ . For example, a gonio stage or the like can be employed. The rotation direction may be around one axis or around two axes as necessary. And the stage drive part 104a which consists of a feed screw mechanism etc. driven by a step motor is provided, for example, and rotation operation is controlled according to the control signal of the control part 16 mentioned later.

Laser light emitted from a laser oscillator (1), L ₂ (L ₃₎ of the end face of the optical attenuator (3), a laser beam L ₂ (L ₃₎ for adjusting the light quantity of the optical path formed on the laser beam L ₂ (L ₃₎ A homogenizer 102 is formed as a homogenizing optical system for uniformizing the intensity distribution.

Since the homogenizer 102 is known in various configurations, for example, using a fly's eye lens, a diffraction element, an aspherical lens, or a kaleido type rod, any configuration may be employed as necessary. You may also

The configuration and operation of the micro mirror array 7 are the same as described with reference to FIG. 2.

The inclination stage 105 is a rotation mechanism which supports the micromirror array 7 so that rotation is possible centering on the rotation center 105C located in the substantially center of the reference reflection surface 7a. For example, a gonio stage or the like can be employed. The rotation direction may be around one axis or around two axes as necessary. And the stage drive part 105a which consists of a feed screw mechanism etc. driven by a step motor is provided, for example, and a rotation operation is controlled according to the control signal of the control part 16 mentioned later.

The center of rotation 105C and the center of rotation 104C of the inclined stage 104 coincide substantially.

As shown in FIG. 6, in the irradiation optical system 20, the imaging lens 11 and the objective lens 14 arranged such that the optical axis 202 passes through the rotation centers 104C and 105C include the reference reflecting surface 7a. It is an imaging optical system provided so that the to-be-processed object 15 may become substantially airspace. For example, an optical system such as a microscope may be employed.

Since the configuration and the positional relationship of the objective lens 14, the imaging lens 11, the translucent mirror 12, the CCD 10, the translucent mirror 8, and the like are the same as those of the first and second embodiments described above, The description is omitted.

The control part 16 controls the whole laser processing apparatus 200, and is sent out from the operation input from the operation part 17, CCD 10, and operation part 17, and is sent out from the CCD 10 to perform operation input. A monitor 9 for displaying an image signal is connected.

The laser oscillator 1, the micromirror array 7, and the stage drivers 104a and 105a, which are at least controlled, are electrically connected to each other, and control signals for controlling their operations can be transmitted to each of them.

As in the first embodiment, the control unit 16 sends a control signal to the laser oscillator 1 to select one of the laser beams L ₂ and L ₃ to turn on or turn off the light.

In addition, the micro mirror array 7 transmits a control signal for controlling the on state and the off state of each micromirror 7b so that the irradiation area of the modulated light L _M can be matched with the area to be processed.

The control unit 16 calculates the diffraction direction D (see FIG. 2) with respect to the stage driving units 104a and 105a in accordance with the wavelength of the laser light set by the operation unit 17, and the diffraction direction D corresponds to the optical axis 202. A control signal is sent to rotate at least one of the inclination stages 104 and 105 so as to coincide. That is, the control part 16 comprises the rotation mechanism control part which drives a rotation mechanism.

Here, the setting method of the diffraction direction D will be described.

In the micromirror array 7, since the micromirror 7b which has a square reflection surface is arrange | positioned in the longitudinal and horizontal lattice form, diffracted light distributes in two dimensions. Depending on the arrangement of the laser oscillator 1, the micromirror array 7, and the irradiation optical system 20, as shown in FIG. 9, the optical axis 202 of the irradiation optical system 20 positioned at (αo, βo) With respect to, it is distributed irrespective of each diffraction direction. Here, a circle represents the diffraction direction of the laser beam L ₂ of the wavelength λ ₂ , and the X mark represents the diffraction direction of the laser beam L ₃ of the wavelength λ ₃ , respectively. Reference numeral 20 denotes a rear angle opening of the irradiation optical system 20.

FIG using 3 as described above, the laser light L _2, L ₃ are, so harmonics of the fundamental wavelength λ _1, the wavelength λ _2, λ ₃ ratio, precisely an integer ratio of 3: 2 is a. Thus, m _x, when the m _y by an integer, the diffraction order of laser light _{L 2 (2 · m x,} 2 · m y) order, the diffraction order of laser light _{L 3 (3 · m x,} 3 · m y) Each diffraction direction of the difference coincides.

In this case, for example, at wavelength λ ₃ , the diffracted light in the diffraction direction 206 near the optical axis 202 is almost incident, so that the light having high diffraction efficiency is incident. On the other hand, when the wavelength is changed to λ ₂ , the light incident on the irradiation optical system 20 is dispersed in three kinds of diffraction directions 207, resulting in light having low diffraction efficiency, so that the amount of incident light decreases.

Therefore, in the present embodiment, at least one of the inclination stages 104 and 105 is driven to rotate the diffraction direction so as to be in a state as shown in FIG. That is, the diffraction directions 204 and 205 corresponding to the diffraction orders of which the diffraction directions are common are moved to the positions of (αo, βo).

About the positional relationship of a diffraction direction, it has already demonstrated using Formula (1) and FIG. For example, when the array pitch of the micromirrors of the micromirror array 601 is T = 16 μm, when the incident angle θ _i = 23.8 ° and the second harmonic with a wavelength of 532 nm is incident, 12 (= 2 × 6) The diffraction angle of the differential diffracted light is θ _d = 0.2 °. Further, when the third harmonic having a wavelength of 354.7 nm is incident at the same incidence angle θ _i , the diffraction angle of the 18 (= 3 × 6) order diffracted light becomes θ _d = 0.2 °, and both sides coincide.

Thus, the inclination such that with respect to the optical axis 202, the diffraction direction D so as to match the tilt stage then the reference reflecting surface of the rotating (105), and (7a), the laser beam L _2, the angle of incidence is the θ _i of L ₃ The stage 104 is rotated. In this way, even if the wavelength of the YAG laser is switched, the incident condition to the optical system after the micromirror array 601 does not change, and the utilization efficiency of the laser light amount can be maximized.

And even when using the micromirror array 7 in which the inclination-angles phi _ON of the small mirror 7b differ, similarly, since the incident angle (theta) _i which maximizes light utilization efficiency is calculated, inclination stages 104 and 105 accordingly. ) Can be rotated. Therefore, the inclination angle φ _ON is not limited to 12 degrees.

As mentioned above, although the example of a diffraction order was demonstrated in one dimension, it is the same also in the general case where a diffraction order becomes two dimensions. That is, since the uth harmonic has m _x and m _y as an integer, and the diffraction directions of the (u · m _x , u · m _y ) diffraction light all match exactly, the inclination stage 104 is adapted to the diffraction direction and the incident angle. , 105), the diffraction efficiency can be maximized.

Fig. 6 shows such a state. The diffracted light 121 corresponds to the diffraction directions 204 and 205 of FIG. 3, and the diffracted lights 120 and 122 correspond to other diffraction directions.

And since the diffraction direction D is a function of the two-dimensional incidence angle θ _i , the degree of freedom of angle adjustment may be two degrees of freedom. Therefore, when the inclination stages 104 and 105 rotate around two axes, respectively, the above adjustment can be performed only by rotating one of them. Further, the inclined stages 104 and 105 may be rotated around one axis in the independent direction.

Next, the operation of the laser processing apparatus 200 according to the present embodiment will be described.

FIG. 7: is a figure for demonstrating typically the initial state of the laser processing apparatus which concerns on the Example of this invention.

In the initial state of the laser processing apparatus 200, as shown in FIG. 7, the inclination stages 104 and 105 are set to the reference position of rotation, and the positional relationship of the laser oscillator 1 and the micromirror array 7 is Not optimized Therefore, in general, when the laser beam L ₂ (L ₃ ) is irradiated in that state, all of the diffracted lights 12O, 121, 122 and the like are shifted from the optical axis 202, and as shown in FIG. 3, the irradiation optical system Since the light incident on (20) is dispersed into a plurality of diffracted light, the intensity of light irradiated onto the workpiece 15 decreases as a result.

Therefore, before irradiating a laser beam, the initial setting operation for optimizing the rotation position of the inclination stages 104 and 105 is performed.

That is, for the wavelengths λ ₂ and λ ₃ of the laser beam that can be emitted, the positional relationship between the laser oscillator 1 and the micromirror array 7 which coincides the common diffraction direction D with the optical axis 202 is set in the diffraction direction described above. It calculates by the control part 16 based on the method, and the control signal corresponding to the rotational position of the inclination stage 104,105 is sent to the inclination stage 104,105.

Next, using the laser processing apparatus 200, the processing pattern data for laser processing is created. Therefore, the illumination light L _ob is emitted from the light source 13, reflected by the translucent mirror 12, and is illuminated on the workpiece 15 through the objective lens 14.

The reflected light of the illumination light L _ob passes through the objective lens 14, the translucent mirror 12, and the imaging lens 11, respectively, is reflected by the translucent mirror 8, and is imaged by the CCD 10. And the image of the surface of the to-be-processed object 15 by illumination light L _ob is sent to the control part 16 as an image signal 150A.

The control unit 16 converts the image signal 150A into image data and displays it on the monitor 9. And the operator observes the image of the monitor 9, designates the defect part or cut part which should be processed through the operation part 17, or image-processes the image data by the control part 16, and automatically extracts a defect part or cut part, The processing pattern data 151 corresponding to the image data of these defective portions and cut portions is created.

The processing pattern data 151 is control data for causing the laser beam irradiation region to correspond to the on state of each of the micromirrors 7b of the micromirror array 7.

Next, an operator selects the wavelength used for laser processing, for example, (lambda) ₂ , from the operation part 17, performs an operation input which instruct | indicates a processing start, and starts a laser processing process.

In the laser processing step, the control unit 16 transmits a control signal for oscillating the laser light L ₂ to the laser oscillator 1 and transmits the processing pattern data 151 to the micromirror array 7.

In the laser beam L ₂ , the light intensity is adjusted by the light attenuator 3, the distribution of light intensity in the cross-sectional direction is uniformized by the homogenizer 102, and the reference reflecting surface 7a of the micromirror array 7 is provided. Is incident at a constant incident angle θ _i .

A micro mirror array (7), each micromirror (7b) the processing pattern data because the on-state and the inclination angles in the off state control in accordance with 151, the laser light L ₂ of the ON state of the micromirrors (7b) Only the incident portion is reflected in the specular reflection direction R (see Fig. 2).

At this time, in the region where the micromirrors 7b in the on state are collected, diffraction occurs and is diffracted in the direction corresponding to the diffraction order. In the present embodiment, since the diffraction direction D and the regular reflection direction R coincide, the light intensity does not decrease in the state where the diffraction efficiency is maximum, but is reflected in the direction of the emission angle θ ₀ (see FIG. 2) and thus the translucent diameter (8). Through).

And it enters into the imaging lens 11 which has arrange | positioned the optical axis 202 so that it may correspond to the diffraction direction D, and is imaged on the to-be-processed object 15 by the objective lens 14. As shown in FIG. Therefore, modulated light L _M is irradiated to the area | region corresponding to the processing pattern data 151 on the to-be-processed object 15. FIG. Therefore, the area corresponding to the processing pattern data 151 is laser processed by the modulated light L _M.

On the other hand, since the light reflected by the off-state micromirror 7b is reflected in the direction which does not enter the imaging lens 11, it does not reach the to-be-processed object 15. FIG.

Thus, in the laser processing apparatus 200, it can process by creating the processing pattern of the area | region to laser-process from the image of the to-be-processed object 15, and irradiating the laser beam of 1 shot to the area | region matching the said processing pattern. have.

Then, from the operation unit 17, an operation input for switching the wavelength of the laser light used for processing is performed, and the control unit 16 sends a control signal for switching the wavelength of the radar light to the laser oscillator 1 to switch the wavelength. Laser processing can be performed. For example, instead of laser light L ₂ , laser light L ₃ is selected, and a laser processing process can be performed in the same manner as above.

At that time, since the laser light L ₃ has a different wavelength, it is diffracted in a diffraction pattern different from that of the laser light L ₂ , but the diffraction directions D coincident with the normal reflection direction R of the micromirror 7b in the on state are wavelengths λ ₂ and λ _3. In the case of laser light L ₃ , the light is emitted in a state where the diffraction efficiency is most high toward the diffraction direction D by the micromirror 7b in the on state.

Therefore, in accordance with the change in the diffraction direction due to the difference in wavelength, for example, without incurring effort to move the installation position of the irradiation optical system 20, the wavelength of the laser oscillator 1 is instructed to be changed. Laser processing by means of the same diffraction efficiency can be realized.

In addition, according to the present embodiment, the inclination stages 104 and 105 are provided so that even if the inclination angle of the micromirror 7b of the micromirror array 7 is constant, the light having high diffraction efficiency is applied to the irradiation optical system 20. Can be incident. Therefore, since the device can be configured as a standard product without using a special order product such as the inclined angle of the micromirror 7b, there is an advantage that the device can be made simple and inexpensively.

[Fourth Embodiment]

Next, a fourth embodiment of the present invention will be described.

8 is a diagram for schematically illustrating a schematic configuration of a laser processing apparatus 210 according to a fourth embodiment of the present invention.

The laser processing apparatus 210 of this embodiment removes the inclination stage 105 of the laser processing apparatus 200 of the said 3rd Example, and positions the micromirror array 7 relative to the laser oscillator 1 with respect. Is integrated with the fixed modulated light generator 30, and the modulated light generator 30 is rotatably held by the inclined stage 104. FIG. The position of the micromirror array 7 is a position where the optical axes of the laser beams L ₂ and L ₃ enter at a constant incidence angle about the center of the reference reflecting surface 7a.

Hereinafter, a brief description will be given focusing on the differences from the third embodiment.

According to the configuration of this embodiment, in the third embodiment, it corresponds to the case where the inclined stages 104 and 105 are rotated in synchronization. Since the inclined stage 104 is rotatable in the biaxial direction, the diffraction direction D and the optical axis 202 can coincide.

In this case, since the inclination stage 105 can be removed, there is an advantage that a simple structure and an inexpensive apparatus can be used.

Incidentally, in the above description, the case where the laser light consists of two harmonics has been described, but the number of harmonics may be three or more. In this case, the diffraction directions common to each can be set as follows.

That is, when a plurality of harmonics are n (n≥3) u _th harmonics (u _k is an integer different from each other, k = 1, 2, ..., n), the diffraction direction common to these plurality of wavelengths As a diffraction order, it may be set in a direction in which (u _k · m _x , u _k · m _y ) differences (where m _x and m _y are integers).

In addition, in the above description, an example in which the laser light has a plurality of wavelengths by harmonics of the fundamental wavelength has been described, but the plurality of wavelengths is not limited to harmonics. For example, it may be a laser light having a plurality of wavelengths emitted from a separate light source.

The plurality of wavelengths preferably form an integer ratio accurately, but may be substantially an integer ratio as long as the change in diffraction efficiency is within an acceptable range. In this case, diffraction directions common to each do not exist, but diffraction directions close to each other exist. Therefore, by aligning the optical axes of the irradiation optical systems in one of these diffraction directions close to each other or in their average diffraction directions, an effect similar to that in the case of the constant ratio can be obtained.

The degree to which an almost integer ratio is achieved is set by the degree of agreement of a diffraction direction. For example, when m _x and m _y become large, the diffraction direction is shifted in proportion to the shift of the integer ratio, so it is preferable to approach a more accurate integer ratio. On the other hand, when m _x and m _y are relatively small, even if they deviate from the exact integer ratio, the amount shifted in the diffraction direction becomes small, and good diffraction efficiency can be obtained. It is preferable to set the shift amount of the diffraction direction smaller than at least the rear angle opening of the irradiation optical system 20.

In this case, the wavelength of the plurality of laser light sources, one to n _k λu when La (u _k are mutually different integers, k = 1, 2, ··· , n), of a certain wavelength λ (n ≥ 2) On the other hand, λu _k is set to be approximately (λ / u _k ), and the diffraction order is the (u _k · m _x , u _k · m _y ) difference (where m _x , m _y is an integer).

For example, using a nitrogen laser (wavelength lambda ₂ = 3371 nm) and a second harmonic of the YAG laser (lambda ₃ = 532 nm), two wavelength ratios lambda ₂ : lambda ₃ are approximately an integer ratio of 5: 8. Can be.

In addition, in the above description, an example in which the laser beam is deflected by the plane mirror 6 in order to inject the laser beam into the micromirror array 7 at a predetermined angle has been described. , The plane mirror 6 may be omitted.

In the above description, an example in which two of the second and third harmonics are used as the harmonics will be described. If necessary, three or more harmonics may be used. In addition, you may select the order of harmonics at random.

In that case, when a plurality of harmonics are n (n? 2) u _th harmonics (u _k is a different integer from each other, k = 1, 2, ..., n), they are common to the plurality of wavelengths. What is necessary is just to set it as the diffraction direction in the direction where each diffraction order is (u _k * m _x , u _k * m _y ) (wherein m _x and m _y are integers).

In addition, although the above description demonstrated the example which aligns the optical axis of the irradiation optical system with the diffraction direction which is common to or substantially coincides with all of the plurality of wavelengths, only a part of the plurality of wavelengths may be used depending on the processing conditions. In that case, according to the wavelength which a rotation mechanism control part uses for a process, the direction in which the diffraction direction is substantially corresponded may be calculated, and a control signal may be sent so that the optical axis of an irradiation optical system may be aligned.

Moreover, there may be only one type of wavelength used for a process, and in that case, the suitable diffraction direction and the optical axis of an irradiation optical system can be matched.

In the above description, the rotating mechanism control unit calculates the rotating position of the rotating mechanism and sends out a control signal. However, the positional relationship is calculated in advance according to the wavelengths or combinations of all the laser beams of the laser light source. The result may be stored, for example, in a data table or the like.

The laser processing method and apparatus of the present invention can also be applied to technical fields such as micro die sections for microscopic cutting of biological samples.

In addition, the structure disclosed above is not limited to the structure of each Example, If it can implement, it can implement combining suitably within the range of the technical idea of this invention.

According to the laser processing method and the laser processing apparatus of the present invention, even if a plurality of wavelengths of laser light are switched, the modulated light is reflected in one direction and is incident on the modulated light irradiation optical system, so that the utilization efficiency of the laser light can be improved, The workpiece can be processed efficiently.

Claims (17)

From a laser light source for generating laser light having a plurality of wavelengths, the laser light is irradiated toward an active optical element in which a plurality of active optical elements are regularly arranged, and the laser beam corresponds to a cross-sectional shape corresponding to the processing pattern of the workpiece. A laser processing method for converting into modulated light having a light beam, and irradiating the workpiece with a modulated light irradiation optical system to perform laser processing, And a direction in which the diffracted light of the plurality of wavelengths generated in the active optical element is directed in the direction of the optical axis of the modulated light irradiation optical system by the laser light having the plurality of wavelengths. The method of claim 1, The optical axis of the modulated light irradiation optical system, The laser processing method according to claim 1, wherein the laser beams having the plurality of wavelengths are directed in a direction common to the plurality of wavelengths among diffraction directions of diffracted light generated in the active optical element. The method according to claim 1 or 2, The laser processing method characterized by forming the said laser beam which has the said some wavelength from the some harmonic by one laser light source. The method according to claim 1 or 2, A laser processing method, wherein the laser light having the plurality of wavelengths is formed by a plurality of laser light sources having different wavelengths. The method according to claim 1 or 2, And said active optical element is a micromirror array having as said plurality of active optical elements a plurality of small mirrors provided such that tilt angles are switchable. The method of claim 5, And an inclination angle of the compact mirror is set such that the inclined angle of the small mirror reflects the modulated light in the optical axis direction of the modulated light irradiation optical system in the ON state in which the laser light is reflected as the modulated light. The method of claim 3, When the plurality of harmonics are n (n ≥ 2) u _th harmonics (u _k is an integer different from each other, k = 1, 2, ..., n), As a diffraction direction common to the plurality of wavelengths, in a direction in which the diffraction orders of the plurality of harmonics are (u _k · m _x , u _k · m _y ) differences (where m _x and m _y are integers) The laser processing method characterized by the above-mentioned. 5. The method of claim 4, The wavelength of the plurality of laser light sources, n pieces _{(n ≥ 2) λu k (} u k are mutually different integers, k = 1, 2, ... . N) of and, For a certain wavelength λ, when λu _k is (λ / u _k ), As a diffraction direction common to the plurality of wavelengths, the diffraction orders of the laser beams having the plurality of wavelengths are (u _k · m _x , u _k · m _y ) differences (where m _x and m _y are integers) The laser processing method characterized by setting to the phosphorus direction. A laser light source for generating laser light having a plurality of wavelengths; An active optical element in which a plurality of active optical elements are regularly arranged, and converting the laser light into modulated light having a cross-sectional shape corresponding to the processing pattern of the workpiece; A laser processing apparatus comprising a modulated light irradiation optical system for irradiating the modulated light onto a workpiece, And a direction in which the diffracted light of the plurality of wavelengths generated in the active optical element is directed in the direction of the optical axis of the modulated light irradiation optical system by the laser light having the plurality of wavelengths. 10. The method of claim 9, The optical axis of the modulated light irradiation optical system, And a laser beam having the plurality of wavelengths so as to be directed in a direction common to the plurality of wavelengths among diffraction directions of diffracted light generated in the active optical element. 11. The method according to claim 9 or 10, Wherein the active optical element comprises, as the plurality of active optical elements, a micromirror array having a plurality of micromirrors that deflect the laser light by switching an inclination angle, The inclination angle of the micromirror is set to an angle for reflecting the laser light in the optical axis direction of the modulated light irradiation optical system. 10. The method of claim 9, A rotation mechanism for changing the inclination of at least one of the laser light source and the active optical element with respect to the modulated light irradiation optical system, The modulated light irradiation optical system irradiates the workpiece with modulated light deflected along any one of the at least two directions by the active optical element, The rotation mechanism is a laser processing apparatus, characterized in that the output angle of the modulated light traveling along the optical axis of the modulated light irradiation optical system to the active optical element is variable. The method of claim 12, And the rotation mechanism rotates to change the inclination of the laser light source with respect to the active optical element. The method according to claim 12 or 13, And the rotating mechanism rotates to change the inclination of the active optical element with respect to the modulated light irradiation optical system. The method according to claim 12 or 13, And a rotation mechanism control unit for calculating a diffraction direction of the modulated light from the rotation position of the rotation mechanism and the wavelength of the laser light, and for driving the rotation mechanism such that the diffraction direction coincides with the optical axis of the modulated light irradiation optical system. Laser processing equipment. 16. The method of claim 15, The laser light source generates switchable laser light having two or more different wavelengths, and the tilting mechanism control unit causes the optical axis of the modulated light irradiation optical system to coincide in a diffraction direction common to the wavelength of each laser light. The laser processing apparatus characterized by the above-mentioned. The method according to claim 12 or 13, And said active optical element is a micromirror array comprising a plurality of micromirrors for changing a tilt angle and deflecting said laser light in at least two directions as a plurality of deflection elements.

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