JP2007326132A - Laser beam machining apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser beam machining apparatus capable of machining a workpiece with excellent accuracy even when changing the inclination of a reference plane of a spatial modulation element with respect to the optical axis of a projection optical system. <P>SOLUTION: The laser beam machining apparatus 100 comprises a machining light source 1 for generating laser beams, a very small mirror array 3 for performing the spatial modulation of laser beams generated by the machining light source 1 by a plurality of very small mirrors on a very small mirror array surface 3A, a projection optical system 51 for projecting the machining reflected light 4 subjected to the spatial modulation by the very small mirror array 3 on a workpiece 10, and an image processing unit 15 which picks up an image of a workpiece surface 10a and generates the modulation data 208 for driving the very small mirror array 3 from the image of the workpiece surface 10a. The image processing unit 15 has an irradiation deviation correction means for correcting any deviation of an irradiation range of the machining reflected light 4 generated according to the inclination of the very small mirror array surface 3A with respect to the optical axis of the projection optical system 51. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a laser processing apparatus. For example, the present invention relates to a laser processing apparatus that performs removal, cutting, and the like of a specified region of a workpiece by irradiating laser light.

2. Description of the Related Art Conventionally, a laser processing apparatus that performs processing by irradiating a desired region of a workpiece with laser light is known. For example, in the manufacture of a liquid crystal display or the like, a laser repair apparatus is known as means for correcting a defective portion such as an unnecessary residue existing in a wiring pattern on a glass substrate or a photomask used for exposure.
In this laser processing apparatus, the size of the laser light irradiation area is defined by a variable rectangular opening or the like, but recently, an apparatus using a spatial modulation element such as a micromirror array is also known.
For example, Patent Document 1 includes a laser source, a processing table on which a workpiece is placed, and a micromirror array (micromirror array). The angles of a plurality of mirror pieces of the micromirror array are turned ON / OFF. A laser processing apparatus is described in which an arbitrary pattern shape is formed on a workpiece by switching by control.
As the wavelength of the laser used in the laser processing apparatus, an appropriate wavelength is selected depending on the processing target. For example, in a laser repair apparatus, a wavelength that is easily absorbed by a workpiece is used, such as a visible to infrared band for correcting a metal film and an ultraviolet band for a transparent film. In order to switch the wavelength, there are devices equipped with a plurality of lasers, devices capable of switching a plurality of harmonics of one fundamental wavelength laser, and the like.
JP-A-8-174242 (page 3-4, FIG. 1-2)

However, when laser processing is performed by a laser processing apparatus using a spatial modulation element in which a plurality of modulation elements are regularly arranged, such as a micromirror array as in Patent Document 1, an image of the micromirror array is obtained with a microscope. Reduce and project onto the work piece. Since the inclination angle of the micromirror cannot be set freely, the reference surface of the spatial modulation element is often inclined with respect to the optical axis of the projection optical system. In that case, since the image plane rotates and distortion occurs in the image formed by the modulated light on the processing surface, there is a problem that good processing accuracy may not be obtained.
Further, since the micromirror array has a structure in which small mirrors are arranged at equal intervals, the laser light reflected from the micromirror array is divided into a plurality of diffracted lights. However, since the rear numerical aperture of the microscope is generally small, it is not possible to enter all of the divided diffracted lights. For this reason, there is a problem that a phenomenon of reducing the utilization efficiency of the laser beam occurs simply by setting the optical axis of the microscope that irradiates the laser beam in the regular reflection direction by the micromirror.

The fact that the latter case may cause inconvenience will be described with reference to FIG.
FIG. 13 is an example of the angular distribution of diffracted light in a laser processing apparatus capable of switching the second harmonic (wavelength λ ₂ = 532 nm) and the third harmonic (wavelength λ ₃ = 354.7 nm) of the YAG laser. That is, the angle distribution (α, β) of the diffracted light reflected from the micromirror array is plotted on an angle plane 501 with the optical axis 502 of the microscope as the center.

At the wavelength λ ₃ , there is one diffraction order 504 in the vicinity of the optical axis 502, as indicated by a cross in the figure. Since the small mirror corresponding to the irradiation region of the laser beam is inclined so as to reflect the laser beam in the direction of the optical axis 502, the diffraction order 504 close to the optical axis 502 is the only diffracted light having a large intensity. Since this diffraction order 504 is within the range of the rear-side angular opening 503 of the microscope, the work piece can be efficiently irradiated with the intensity of the laser beam.
On the other hand, when switching the wavelength lambda _2, as shown in the illustrated circle, diffraction orders near the optical axis 502 is no, the similar angle position spaced four diffraction orders 505 are present. Therefore, the intensity of the laser is dispersed in the plurality of diffraction orders 505 and does not enter the rear angle opening 503 of the microscope. That is, when the wavelength λ ₂ is used, one diffraction order can be made incident by changing the incident angle with respect to the microscope, but the utilization efficiency of the laser beam is still not improved.
In such a case, it is conceivable to improve the laser beam utilization efficiency by changing the tilt angle of the reference surface of the micromirror array depending on the wavelength. However, by changing the tilt angle of the reference surface, distortion of the image of the micromirror array is possible. However, there is a problem that processing accuracy varies.

  The present invention has been made in view of such problems, and can process a workpiece with good accuracy even if the inclination of the reference plane with respect to the optical axis of the projection optical system of the spatial modulation element is changed. An object is to provide a laser processing apparatus.

In order to solve the above-described problems, a laser processing apparatus according to the present invention includes a laser light source that generates laser light, and a plurality of modulation elements that are regularly arranged on a reference plane with the laser light generated by the laser light source. A spatial modulation element that spatially modulates by means of: a projection optical system that projects modulated light spatially modulated by the spatial modulation element onto a workpiece; and imaging the surface to be processed, and the spatial modulation from the image of the surface to be processed A modulation data generation unit that generates modulation data for driving the element, and correction of a deviation of an irradiation range on the processing surface of the modulated light generated according to the inclination of the reference surface with respect to the optical axis of the projection optical system It is set as the structure provided with the irradiation deviation correction means to perform.
According to the present invention, the irradiation deviation correction means can correct the deviation of the irradiation range that occurs according to the inclination of the reference plane with respect to the optical axis of the projection optical system of the spatial modulation element. Even when tilted with respect to the optical axis of the projection optical system, laser processing can be performed without being affected by distortion of the irradiation range of the modulated light on the processing surface.

In the laser processing apparatus of the present invention, the irradiation deviation correction unit responds to distortion of the image of the modulated light due to the inclination of the reference plane with respect to the optical axis of the projection optical system with respect to the captured image of the processing surface. Preferably, the modulation data is generated by performing image processing for eliminating the deviation of the irradiation range.
In this case, since the deviation of the irradiation range is corrected by performing image processing on the captured image of the processing surface, it can be easily corrected even when the distortion of the image of the modulated light becomes complicated. For example, even when changing the laser light source or the projection optical system, or when changing the tilt in various ways, it is easy to make a suitable correction for each by storing a plurality of image processing conditions according to each case. And can be done quickly. Further, when changing the projection optical system, it is possible to simultaneously correct image distortion due to the aberration of the projection optical system.

Further, in the laser processing apparatus of the present invention, the irradiation deviation correcting means is in accordance with the inclination of the reference surface with respect to the optical axis of the projection optical system in the optical path between the spatial modulation element and the processing surface. Preferably, the image forming apparatus includes a correction element that optically corrects distortion of the image of the reference surface projected onto the processing surface.
In this case, since the distortion of the image of the modulated light projected onto the processing surface is optically corrected by the correction element, it is possible to correct the deviation of the irradiation range of the modulated light without performing a correction operation. Therefore, correction can be performed without changing the pixel configuration for forming the modulated light.
Further, it is possible to correct the deviation of the irradiation range according to various conditions by controlling the correction amount of the correction element or exchanging the correction element.

In the laser processing apparatus of the present invention, the irradiation deviation correction unit includes an imaging unit that images the surface to be processed, and an imaging surface rotation unit that rotates the imaging surface of the imaging unit, and the reference surface According to the inclination of the projection optical system with respect to the optical axis, the imaging surface rotating means rotates the imaging surface of the imaging means, and the modulation is performed based on the image captured on the rotated imaging surface. It is preferable to correct the deviation of the irradiation range by generating data.
In this case, the image pickup surface is tilted with respect to the processing surface by the image pickup surface rotating means in the same manner as the reference surface of the spatial modulation element, and modulation data is generated based on the image picked up on the image pickup surface. Then, an image of the surface to be processed that is distorted in the same manner as that distorted by the inclination of the reference surface with respect to the optical axis of the modulation projection optical system is acquired. Therefore, each distortion is canceled on the surface to be processed, so that the deviation of the irradiation range can be corrected. As a result, it is possible to save the trouble of performing image processing or installing a correction element in order to correct the deviation of the irradiation range, so that the processing efficiency can be improved.

Moreover, it is preferable that the laser processing apparatus of the present invention includes a modulation element rotation mechanism that tilts the spatial modulation element with respect to the optical axis of the projection optical system.
In this case, the emission direction of the modulated light incident on the projection optical system with respect to the spatial modulation element can be changed by rotating the spatial modulation element by the modulation element rotation mechanism. The emission direction of the modulated light can be adjusted to the direction of the diffraction angle of the order as appropriate according to the incident angle to the element. Therefore, modulated light with high diffraction efficiency can be incident on the projection optical system.
Also, in this case, if the information on the tilt of the reference plane with respect to the optical axis of the projection optical system is acquired from the modulation element rotating mechanism, the information on the tilt of the reference plane with respect to the optical axis of the projection optical system can be obtained quickly and accurately. Since it can acquire, it is more preferable.
In addition to such a configuration, in the case of a configuration having a light source unit rotation mechanism that changes the incident angle of laser light to the spatial modulation element, by combining the rotation with the modulation element rotation mechanism, The diffraction conditions of the modulated light incident on the projection optical system can be optimized.
In addition, if the laser light source can be rotated in accordance with the rotation of the spatial modulation element, the emission angle of the modulated light can be changed under the condition that the incident angle of the laser beam is constant. Control becomes easy and the diffraction order of modulated light can be changed efficiently.

In the laser processing apparatus of the present invention, the diffraction direction of the modulated light is calculated from the rotation position of the modulation element rotation mechanism and the wavelength of the laser light, and the diffraction direction is the optical axis of the projection optical system. It is preferable to provide a rotation mechanism control unit that drives the modulation element rotation mechanism so as to match.
In this case, since the diffraction direction of the modulated light can be calculated by the rotation mechanism control unit and the optical axis of the projection optical system can be matched with the diffraction direction, the diffraction efficiency can be automatically optimized.

In the laser processing apparatus provided with the rotation mechanism control unit of the present invention, the laser light source generates two or more different wavelengths of laser light in a switchable manner, and the rotation mechanism control unit includes the respective lasers. It is preferable that the optical axis of the projection optical system is substantially aligned with the diffraction direction common to the wavelength of light.
In this case, when laser processing is performed using laser beams having a plurality of wavelengths, the diffraction efficiency of the modulated light can be brought into an optimum state without readjusting the modulated light rotating mechanism even if the wavelengths are switched. Therefore, laser processing with the wavelength switched can be performed quickly, and processing efficiency can be improved.

In the laser processing apparatus of the present invention, the spatial modulation element includes a plurality of micromirrors that switch the tilt angle with respect to the reference plane and deflect the laser light in at least two directions as the plurality of modulation elements. An array is preferred.
In this case, in order to improve the diffraction efficiency of the modulated light, the modulation element rotating mechanism matches the diffraction direction of the modulated light with the optical axis of the projection optical system. The diffraction efficiency of modulated light can be easily optimized, and high-speed and highly efficient laser processing can be performed.

  According to the laser processing apparatus of the present invention, by providing the irradiation deviation correction means, the workpiece can be processed with good accuracy even if the inclination of the reference plane with respect to the optical axis of the projection optical system of the spatial modulation element is changed. There is an effect that can be.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In all the drawings, even if the embodiments are different, the same or corresponding members are denoted by the same reference numerals, and common description is omitted.

[First Embodiment]
A laser processing apparatus according to the first embodiment of the present invention will be described.
FIG. 1 is a schematic device configuration diagram showing a schematic configuration of a laser processing apparatus according to a first embodiment of the present invention. FIG. 2A is a schematic cross-sectional view showing the cross-sectional configuration of the spatial modulation element and the state of the diffracted light in the laser processing apparatus according to the first embodiment of the present invention. FIG. 2B is a schematic cross-sectional view showing the state of diffracted light when the spatial modulation element of FIG. FIG. 3 is a functional block diagram illustrating a schematic configuration of the image processing unit of the laser processing apparatus according to the first embodiment of the present invention. FIG. 4 is an example of an image of a surface to be processed in the laser processing apparatus according to the first embodiment of the present invention. FIG. 5 is an example of an image of a processed surface that does not have a portion to be laser processed. FIG. 6 is an example of a difference image obtained by taking the difference between the image of the processing surface in FIG. 4 and the image in FIG.
In addition, each figure is drawn typically, and the shape, arrangement position, posture, dimensional ratio, and the like of each member may be exaggerated (the same applies to the following).

As shown in FIG. 1, the laser processing apparatus 100 according to the present embodiment spatially modulates one of the laser beams L ₂ and L _{3 having} wavelengths of λ ₂ and λ ₃ according to a processing pattern, and performs processing. It is an apparatus that performs reduction processing such as repair processing by projecting the reflected light 4 on the workpiece 10 in a reduced scale.
Examples of the workpiece 10 include a glass substrate used for a liquid crystal display and a semiconductor substrate in the case of repair processing. In these cases, examples of the processing target include a wiring pattern on the substrate and a defective portion such as an unnecessary residue existing in a photomask used for exposure. Further, for example, when used in a microdissection apparatus, biological samples such as cells can be exemplified.
The laser beams L ₂ and L ₃ are switched and used in accordance with the wavelength absorption characteristics of the processing target. Hereinafter, an example in which the laser processing apparatus 100 performs repair processing will be described as an example.

  The schematic configuration of the laser processing apparatus 100 includes a light source unit 50, a minute mirror array 3 (spatial modulation element), a projection optical system 51, an observation light source 11, a moving stage 14, a movement drive control unit 17, a CCD 13 (imaging means), and The image processing unit 15 (modulation data generation unit) is included. Although not particularly illustrated, an operation unit for operating the laser processing apparatus 100 and a system control unit for controlling the operation of the entire apparatus such as coordinating the operation of each control unit are provided.

The light source unit 50 generates laser light for processing the workpiece 10, and includes a processing light source 1 (laser light source), an illumination optical system 2, and a rotation mechanism 22 (light source unit rotation mechanism).
The processing light source 1 is a laser light source that pulsates laser light having a plurality of wavelengths and emits it as a substantially parallel light beam. In the present 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, and the laser light L _{2 is} respectively switched. , L ₃ can be emitted on the same optical path.

The illumination optical system 2 is an optical system for irradiating laser light L ₂ (L ₃ ) emitted from the processing light source 1 to a micromirror array surface 3A that is a reference surface of the micromirror array 3 described later. If necessary, the luminous flux and the light intensity distribution can be adjusted. For example, examples of the configuration for adjusting the beam diameter include a beam expander and a diaphragm. Moreover, as a structure which arranges light intensity distribution, the optical attenuator which adjusts light quantity, the homogenizer which equalizes cross-sectional intensity distribution, etc. can be mentioned. When a homogenizer is used, various configurations such as a fly-eye lens, a diffractive element, an aspherical lens, and a kaleido type rod can be used as necessary.

The processing light source 1 and the illumination optical system 2 are fixed to a housing (not shown), and centered on one point on the optical axis of the laser light L ₂ (L ₃ ) by a rotating mechanism 22 such as a gonio stage, for example. It is held so as to be rotatable in two axial directions.
The rotation angle of the rotation mechanism 22 is controlled by a rotation control unit 23 (rotation mechanism control unit).

As shown in FIG. 2 (a), the micromirror array 3 is regularly provided with a plurality of micromirrors 3B (modulation elements) inclined in at least two directions according to a control signal on the micromirror array surface 3A. It is arranged. The micromirrors 3B are aligned in a direction along the micromirror array surface 3A when the tilt angle is 0 °.
Then, the light source unit 50, a position where the rotation center matches the rotation mechanism 22 to the center position of the micro mirror array surface 3A, are arranged in a posture, the laser beam L _{2 (L 3)} from the light source unit 50 The micromirror array surface 3A is irradiated.
As the micromirror array 3, for example, an element such as DMD (Digital Micromirror Device) can be adopted. In this embodiment, a DMD in which 800 × 600 16 μm square micromirrors 3B are arranged in a rectangular pattern in a rectangular region is employed.
Each micromirror 3B is driven by a drive unit (not shown) that generates an electrostatic electric field in response to a control signal from the drive control unit 16 at two inclination angles of an on state and an off state, for example, ± 12 °. It is designed to be inclined.
Therefore, the micromirror array 3, and reflects the specular direction 20b of the laser light 20a incident at an incident angle theta ₁ with respect to the micromirror array surface 3A in a micro mirror 3B in the ON state. FIG. 2A shows an example in which the regular reflection direction 20b coincides with the normal N of the micromirror array surface 3A.

The micromirror array 3 of the present embodiment is held so as to be rotatable in two axial directions around the center position of the micromirror array surface 3A by a rotating mechanism 21 (modulation element rotating mechanism) such as a gonio stage. ing. Therefore, the inclination of the micromirror array surface 3A with respect to the optical axis of the laser beam L ₂ (L ₃ ) incident on the micromirror array 3 can be changed.
The rotation angle of the rotation mechanism 21 is controlled by the rotation control unit 23.
Therefore, the micromirror array 3 rotates the rotation mechanism 21 in accordance with the incident direction of the laser light L ₂ (L ₃ ) emitted from the light source unit 50, so that the regular reflection direction of the micromirror 3 </ _b > B in the on state is turned on. It can be tilted so that 20b coincides with the optical axis of the projection optical system 51. Information on the tilt angle of the micromirror array surface 3A, that is, information on the tilt angle with respect to the optical axis of the light source unit 50 and the optical axis of the projection optical system 51 described later will be described later from the rotation control unit 23. It is sent to the image processing unit 15 as tilt angle information 207.
Therefore, as shown in FIG. 1, the reflected light corresponding to the arrangement of the micromirrors 3B in the on state can be incident along the optical axis of the projection optical system 51 as the processed reflected light 4 (modulated light). . On the other hand, the light reflected by the micro mirror 3B in the off state is reflected on the optical path different from the processing reflected light 4 as the processed reflected light 5 (see FIG. 1).
At this time, the micromirror array surface 3A is arranged not to be orthogonal to the optical axis of the projection optical system 51 depending on the tilt angle of the rotation mechanisms 21 and 22, but to be tilted. Hereinafter, the inclination angle of the micromirror array surface 3A with respect to the optical axis of the projection optical system 51 is represented by an angle formed with the normal line N of the micromirror array surface 3A.

The projection optical system 51 is disposed between the micromirror array 3 and the workpiece 10, and has a conjugate positional relationship between the center of the micromirror array surface 3A and the processing center on the processing surface 10a. The processing reflected light 4 reflected in step S4 is reduced and projected onto the processing surface 10a. In this embodiment, the processing reflected light 4 is composed of an imaging lens 7 and an objective lens 9 constituting a microscope.
The objective lens 9 has an infinity design on the image side, and the laser light L ₂ (L ₃ ) is a parallel light beam on the optical path between the imaging lens 7 and the objective lens 9.

In the optical path between the micromirror array 3 and the imaging lens 7, a beam splitter 6 that branches the optical path of the light transmitted through the projection optical system 51 is arranged in order to acquire an image of the processing surface 10 a. Yes.
The beam splitter 6 may be, for example, a half mirror, but a coating having a wavelength characteristic is applied to the surface of the beam splitter so as to transmit the wavelengths of the laser beams L ₂ and L ₃ and reflect the light other than those wavelengths. May be used.
Further, in the optical path between the imaging lens 7 and the objective lens 9, the light from the observation light source 11 disposed on the side of the optical path is reflected and guided to the objective lens 9, on the processing surface 10 a. And a beam splitter 8 that transmits the light from the observation light source 11 reflected by the processing surface 10 a and guides it to the imaging lens 7.
As the beam splitter 8, for example, a half mirror or a polarization beam splitter can be adopted.
The beam splitters 6 and 8 may be always arranged in the optical path. For example, each of the beam splitters 6 and 8 is held so as to be able to advance and retract on the optical path by an appropriate advancing / retracting mechanism, and retracted out of the optical path during laser processing Also good.

  The observation light source 11 is a light source that generates illumination light for illuminating the processing surface 10a. The observation light source 11 may be any light source as long as it can illuminate the processed surface 10a with a wavelength sensitive to the CCD 13, which will be described later. For example, a light source in the visible light region such as a halogen lamp is adopted. be able to. Further, if necessary, a polarizing filter or the like may be provided so that the polarization state of the illumination light can be controlled.

The moving stage 14 places the workpiece surface 10 a of the workpiece 10 on the projection surface of the projection optical system 51, and moves the position of the workpiece 10 on a plane orthogonal to the optical axis of the projection optical system 51 2. It is an axis movement stage.
The movement drive control unit 17 is a control unit that controls the amount of movement of the movement stage 14. For example, the movement drive control unit 17 drives the movement stage 14 in accordance with an input from an operation unit (not shown).

The CCD 13 is a two-dimensional image sensor for imaging the processing surface 10 a viewed through the projection optical system 51, and the image on the optical path branched in a direction intersecting the optical axis of the projection optical system 51 by the beam splitter 6. It is arranged at the surface position.
The imaging signal 200 obtained by the CCD 13 is sent to the monitor 12 for display on the monitor 12 and to the image processing unit 15.

The image processing unit 15 generates modulation data for performing on / off drive control of each micromirror 3B of the micromirror array 3 from the image of the processing surface 10a. Or a computer having a CPU, a memory, an input / output interface, an external storage unit, and the like.
As shown in FIG. 3, the schematic configuration includes an image capture unit 24, an image comparison unit 25, an image data storage unit 29, a defect extraction unit 26, an image correction unit 27 (irradiation deviation correction means), and a correction data storage unit. 28. For example, when configured by a computer, each function is realized by executing a program corresponding to these functions by the CPU.

The image capturing unit 24 acquires the imaging signal 200 from the CCD 13, performs noise removal processing, shading correction, and the like as necessary to generate processed surface image data 201 that is a two-dimensional image of the processed surface 10a. Are sent to the image comparison unit 25.
For example, the processed surface image data 201 includes, as shown in FIG. 4, a processed surface image including a repetitive pattern 30a such as a lattice shape and a defect image 30b different from the repetitive pattern 30a on the processed surface 10a. 30 is image data representing 30.

The image comparison unit 25 calls the normal image data 202 when there is no defect portion or the like from the data storage unit 29, performs comparison calculation processing with the processed surface image data 201, for example, difference calculation, and the like, and repeat pattern 30a. The difference image data 203 corresponding to the image of only the defect portion image 30b is generated and sent to the defect extraction portion 26.
For example, the normal image data 202 is image data corresponding to the normal image 31 including only the repeated pattern 30a shown in FIG. The normal image data 202 is stored in the data storage unit 29 in advance according to the type of the workpiece 10, the manufacturing process, and the like.

The defect extraction unit 26 extracts a defect portion to be removed or shaped by laser processing from the difference image data 203 based on the defect information 204 stored in the data storage unit 29, and the defect portion image data 205. Is sent to the image correction unit 27.
Any known algorithm may be used as an algorithm for extracting a defective portion from the difference image data 203. For example, whether or not to perform the feature extraction of the difference image data 203, determine the defect type based on the defect information 204 from the feature, for example, shape, size, luminance level, etc., and perform removal, shaping, etc. judge.
For example, in the case where image noise remains in the difference image data 203, it is excluded in accordance with the characteristics of the image noise included in the defect information 204, or the defect portion does not have the feature of the corresponding defect portion. Will not be extracted.
In the following description, it is assumed that image data corresponding to the defective portion image 30b as shown in FIG. 6 is generated as the defective portion image data 205.

When the defect portion image data 205 includes image distortion due to the inclination of the minute mirror array surface 3 </ b> A, the image correction unit 27 generates modulation data 208 in which the distortion is corrected and sends the modulation data 208 to the drive control unit 16. .
The presence / absence of distortion is determined based on the tilt angle information 207 sent from the rotation control unit 23.
The tilt angle information 207 includes, for example, information representing the rotation amounts of the rotation mechanisms 21 and 22 controlled by the rotation control unit 23 as angles in two axial directions from the reference rotation position. Therefore, the image correction unit 27 can calculate the tilt angle θ of the micromirror array surface 3A with respect to the optical axis of the projection optical system 51 from the tilt angle information 207.
The distortion correction is performed by image processing calculation of the defect portion image data 205 with reference to, for example, the distortion correction information 206 for each inclination angle θ stored in the correction data storage unit 28.
In the distortion correction information 206, distortion correction is performed according to the tilt angle θ and optical parameters of the light source unit 50 and the projection optical system 51, such as the wavelength of the laser light, the magnification of the projection optical system 51, the focal length, and the like. , A data table, or information such as an arithmetic expression for image conversion using the tilt angle θ as a variable is stored.
Note that the distortion correction information 206 is prepared not only for the inclination angle θ but also for optical elements and members that can be switched or exchanged, for example, the objective lens 9 in advance, and each file is in the form of a file or the like. To remember.

Next, the operation of the laser processing apparatus 100 will be described.
FIG. 7 is a flowchart for explaining the operation of the laser processing apparatus according to the first embodiment of the present invention. FIGS. 8A and 8B are a schematic diagram and an enlarged view for explaining the shift of the irradiation range of the modulated light generated on the processing surface. FIG. 9 is a schematic diagram showing an irradiation range corresponding to the corrected modulation data formed by the irradiation deviation correction unit of the laser processing apparatus according to the first embodiment of the present invention.

In order to perform repair processing with the laser processing apparatus 100, first, various initial settings are performed based on processing conditions (step S1).
In this initial setting, the wavelength of the laser beam used for processing is set according to the type of the workpiece 10, the manufacturing process, and the like, and the rotation mechanisms 21 and 22 are driven according to the wavelength, thereby projecting optics. This includes setting the tilt angle of the micromirror array surface 3A with respect to the optical axis of the system 51 and the incident angle of the laser beam.

Here, the reason why the inclination angle of the micromirror array surface 3A and the incident angle of the laser light are changed according to the wavelength of the laser light is to prevent the light intensity from being lowered due to the influence of diffraction in the micromirror array 3. is there.
With reference to FIGS. 2A and 2B, the diffraction that occurs when the laser beam 20a is irradiated will be briefly described.
FIG. 2A shows a plurality of micromirrors 3B in an on state that are inclined from the micromirror array surface 3A by a predetermined angle clockwise in the figure.
In this state, when the laser beam 20a is irradiated onto the micromirror array surface 3A, the diffraction 18 determined by the array pitch of the micromirrors 3B is generated along with the Fraunhofer diffraction 19 determined by the openings (mirror surfaces) of the micromirrors 3B. Arise. The light intensity distribution of the reflected light reflected in the regular reflection direction 20b is a convolution of these diffracted lights.

For example, as shown in the example of the micromirror 3b in FIG. 2A, the Fraunhofer diffraction 19 has an intensity on the peripheral side of each micromirror 3B with the specular reflection direction 20b passing through the center of each micromirror 3B as the axis of symmetry. Forms a line-symmetric light intensity distribution in which the light is attenuated.
On the other hand, the diffraction 18 corresponds to a diffraction order in which diffraction angles are distributed in two axial directions on the micromirror array surface 3A corresponding to the diffraction order determined from the array pitch of the micromirrors 3B and the wavelength of the laser light 20a. Form. The numbers described corresponding to the broken-line arrows in FIG. 2A indicate the diffraction orders in the direction along the plane of the discrete diffraction angles indicated by the arrows (hereinafter sometimes referred to as diffraction directions). . In this case, the 0th-order diffraction direction coincides with the reflection direction of the laser light 20a when the micromirror array surface 3A is a mirror surface. That is, in FIG. 2A, θ ₂ = θ ₁ is satisfied.
In this case, since the regular reflection direction 20b and the (−4) th diffraction direction of the diffraction 18 are shifted by the angle θ ₃ , the actual light intensity distribution obtained by convolving these is the light in the regular reflection direction 20b. The distribution has a relatively reduced strength.

On the other hand, since the projection optical system 51 performs reduction projection, depending on the magnification, the NA on the micromirror array 3 side of the imaging lens 7 is relatively small, and the angle θ ₃ does not fall within the range of the NA. In this case, the intensity of light incident on the imaging lens 7 is significantly reduced.
In order to efficiently guide the laser beam 20a through the projection optical system 51 to the processing surface 10a, the direction in which the maximum value of the light intensity distribution of the reflected light from the micromirror 3B is taken along the optical axis of the projection optical system 51. It is preferable that the light enters the imaging lens 7 perpendicularly. For that purpose, it is important to match the direction of the discrete diffraction angles of the diffraction 18 with the regular reflection direction 20b.

In the present embodiment, as shown in FIG. 2 (b), the micro-mirror array surface 3A by the rotation mechanism 21, by inclining only theta _3/2, the specular direction 20b, (- 4) order diffracted The direction can be matched. Here, 0 ′, −1 ′,..., Etc. represented by broken line arrows indicate the direction of the diffraction 18 before tilting the micromirror array surface 3A, and the solid line arrow indicates the direction of the diffraction 18 after tilting. Show.
Thus, in the present embodiment, focusing on the fact that the diffraction angle of the diffraction 18 is determined by the incident angle of the laser beam, the wavelength, and the arrangement pitch of the micromirrors 3B, the micromirror array surface 3A is rotated to obtain the diffraction angle. The direction of is moved.

In this case, since the incident angle of the laser beam 20a with respect to the micromirror 3B changes, the direction of the regular reflection direction 20b is shifted. However, by changing the incident angle of the laser beam 20a by the rotation mechanism 22, the regular reflection direction 20b. And the diffraction direction can be matched. Further, when the tilt angle of the micromirror 3B can be changed, the tilt angle of the micromirror 3B may be changed for adjustment.
In addition, for the sake of simplicity, the above description has been given by taking an example of adjusting the angle in the uniaxial direction. However, by changing the tilt angle of the micromirror array surface 3A in the biaxial direction, it exists in the depth direction of the paper surface. It is also possible to make the diffraction direction coincide with the regular reflection direction 20b.

In this way, in step S1, for example, when the wavelength λ ₂ is selected, the rotation control unit 23 makes the positional relationship such that the laser light L ₂ enters the imaging lens 7 with the maximum intensity. The rotation mechanisms 21 and 22 are driven. Information on the tilt angle of the micromirror array surface 3A with respect to the optical axis of the projection optical system 51 is sent to the image processing unit 15 as tilt angle information 207.

Next, in step S <b> 2, the movement stage 14 is driven by the movement drive control unit 17 to move the workpiece 10, and the processing position of the processing surface 10 a is moved within the irradiation range of the projection optical system 51. . After the movement is completed, the process proceeds to step S3.
The movement position may be automatically set based on information from another inspection apparatus, or may be manually moved by displaying an image of the processing surface 10a on the monitor 12 and viewing the image. . In the case of manual movement, the end of movement is input from an operation unit (not shown) after the movement is completed.
The image of the processing surface 10a is acquired by illuminating the processing surface 10a using the observation light source 11.
The light from the observation light source 11 is reflected by the beam splitter 8, enters the objective lens 9, and is irradiated onto the processing surface 10a. Then, the reflected light including the image information of the surface to be processed is condensed by the objective lens 9, transmitted through the beam splitter 8 and the imaging lens 7, and condensed and guided to the beam splitter 6. Then, the light is reflected by the beam splitter 6 in a direction intersecting the optical axis of the projection optical system 51 and imaged on the imaging surface of the CCD 13.
The CCD 13 photoelectrically converts the image and sends it to the monitor 12 and the image processing unit 15 as an imaging signal 200. As a result, an image of the processing surface 10 a is displayed on the monitor 12.

In step S <b> 3, the imaging signal 200 sent to the image processing unit 15 is converted into processed surface image data 201 by the image capturing unit 24 and sent to the image comparison unit 25. For example, a processed surface image 30 as shown in FIG. 4 is sent out as processed surface image data 201.
In the image comparison unit 25, the normal image data 202 is called from the data storage unit 29, and the difference image data 203 corresponding to the difference image 32 as shown in FIG. Calculate and send to the defect extraction unit 26 (step S4).
The defect extraction unit 26 performs defect extraction, refers to the defect information 204 stored in the data storage unit 29, and sends the defect part image data 205 including only the defect part image 30b to be repaired to the image correction unit 27. (Step S5).

Next, in step S <b> 6, the image correction unit 27 generates modulation data 208 from the defect portion image data 205 and sends it to the drive control unit 16.
In the process of generating the modulation data 208, image distortion is corrected according to the inclination of the micromirror array 3.
For example, as shown in FIG. 1, if the micromirror array surface 3A is inclined counterclockwise from the position perpendicular to the optical axis of the projection optical system 51, the micromirror array surface 3A These images are also inclined in the same inclination direction on the processing surface 10a. Therefore, for example, if the micromirrors 3B that are turned on are arranged in a rectangular shape on the micromirror array 3, even if the projection optical system 51 does not have any distortion, it is distorted in a trapezoidal shape on the processing surface 10a. The position will be irradiated.
For example, based on the defect portion image data 205, when modulation data for turning on the minute mirror 3B in a long and narrow rectangular shape that removes the defect portion image 30b is generated, reflected light for processing on the processing surface 10a is generated. 4 is a trapezoidal irradiation range 40B shown in FIG. Here, reference numeral 40 </ b> A is a reference pattern described in order to show a state of deformation of all irradiation ranges of the micromirror array 3.
Such distortion is called geometric distortion, and is determined geometrically from the optical parameters such as the tilt direction and tilt angle of the micromirror array surface 3A and the focal length of the projection optical system 51. It is stored in the distortion correction information 206 as a coordinate conversion formula or conversion table for the arrangement position of each micromirror 3B on the micromirror array surface 3A. These conversion formulas can be expressed as a function of the distance from the tilt center and the tilt angle, for example.
Therefore, the amount of distortion can be determined according to the information set in step S1, such as the tilt angle information 207 and the type of the objective lens 9.

In this case, as shown in FIG. 8B, laser processing is performed on the processing target in the processing target irradiation range 40a that overlaps the range of the defect image 30b, and the processing target is not processing in the non-processing target irradiation range 40b. Laser processing is performed on the portion. Further, since the processing reflected light 4 does not reach the unprocessed range 30c, laser processing is not performed.
Therefore, in the image correction unit 27 of the present embodiment, the defect portion image data 205 is subjected to a calculation for correcting the amount of distortion occurring in the irradiation range 40B to generate modulation data 208 corresponding to the irradiation range 40C in FIG. . In FIG. 9, reference numeral 40D is a reference pattern for indicating the amount of distortion to be corrected for the entire area of the micromirror array surface 3A.

Next, in step S <b> 7, the drive control unit 16 performs modulation control of the micromirror array 3 based on the modulation data 208 sent from the image correction unit 27.
Then, the imaging in the CCD 13 is interrupted, and the processing light source 1 is turned on (step S8).
The laser beam L ₂ which is illuminated by the processing light source 1, the illumination optical system 2, if necessary, Hikaritabakei, the light intensity distribution is adjusted is irradiated onto the micro mirror array surface 3A.
On the micromirror array surface 3A, each micromirror 3B is tilted between an on state and an off state according to the modulation data 208, and the processing reflected light 4 is reflected from the micromirror 3B in the on state. On the other hand, the processed reflected light 5 is reflected from the micro mirror 3 </ b> B in the off state and guided in a direction not entering the projection optical system 51.
The processed reflected light 4 travels on the optical axis of the projection optical system 51 in a state where the light amount is not reduced by the diffraction 18, and passes through the beam splitter 6, the imaging lens 7, the beam splitter 8, and the objective lens 9 in this order. The image is projected onto the processing surface 10 a by the action of the imaging lens 7 and the objective lens 9.
At this time, since the modulation data 208 is irradiated onto the range indicated by the defect image 30b, only the necessary processing range is repaired.
When irradiation is performed for a time required for repair processing, all of the micromirror array 3 is turned off, and the irradiation of Sh wisdom and reflected light 4 for processing is terminated.
Above, step S8 is complete | finished.

Next, in step S9, imaging by the CCD 13 interrupted in step S8 is started, and the operator confirms the state of the processing surface 10a by the monitor 12 (step S9).
When it is determined that the repair process has been completed normally, the process proceeds to step S11.
For example, when the processing of the processing target is insufficient, such as when a defect remains, the process proceeds to step S4 and the above steps are repeated.

Step S11 is a step of confirming whether there is any other defect. If there is another place to be repaired, the process proceeds to step S2 and the above steps are repeated.
If there is no other part to be repaired, the repair process is terminated.
This confirmation may be performed by an operator, or, for example, when a large defect is divided and repaired continuously in a plurality of times, it is determined by a system control unit that performs automatic operation.
Further, when processing by changing the wavelength of the laser beam, the above steps are repeated from step S1.

As described above, in the present embodiment, even if the micromirror array surface 3A is arranged to be inclined with respect to the optical axis of the projection optical system 51, the defect generated from the image acquired by the CCD 13 by the image processing unit 15 is used. Since the distortion of the partial image data 205 is corrected and the modulation data 208 is formed, laser processing can be performed with good accuracy without processing the non-processed portion or leaving the defective portion to be processed. It can be carried out.
Since such distortion correction is performed according to the tilt angle information 207 acquired from the rotation mechanisms 21 and 22, even if the tilt of the micromirror array surface 3A is changed by the rotation mechanisms 21 and 22, the distortion can be easily performed. Correction can be performed.
Therefore, in order to correct a decrease in light intensity due to diffraction due to the arrangement pitch of the micromirrors 3B of the micromirror array 3, it is advantageous to improve the processing efficiency when the micromirror array surface 3A is rotated.
Further, it is more suitable when performing laser processing using laser light having a plurality of wavelength lights depending on the processing object.

In addition, since modulation data is generated by performing image processing based on the distortion correction information 206, depending on the setting of the distortion correction information 206, various cases can be flexibly corrected. For example, by including aberration information such as distortion aberration of the projection optical system in the distortion correction information 206, it is possible to correct the displacement of the irradiation range including the aberration.
As described above, since the distortion correction according to the present embodiment is performed by image processing using the image of the processing surface 10a, an observation optical system that images the processing surface 10a and a laser processing optical system that performs laser processing. There is an advantage that it is particularly effective when the optical path and the optical element used are different.

[Second Embodiment]
A laser processing apparatus according to the second embodiment of the present invention will be described.
FIG. 10 is a schematic device configuration diagram showing a schematic configuration of a laser processing apparatus according to the second embodiment of the present invention. FIG. 11 is a functional block diagram illustrating a schematic configuration of an image processing unit of a laser processing apparatus according to the second embodiment of the present invention.

  As shown in FIG. 10, the laser processing apparatus 110 of the present embodiment replaces the image processing unit 15 and the projection optical system 51 of the laser processing apparatus 100 of the first embodiment with an image processing unit 62 (modulation data generation unit). ), A projection optical system 51A, and an imaging lens 70, a distortion correction element 60 (correction element), and a correction element driving unit 61 are added. Hereinafter, a description will be given centering on differences from the first embodiment.

As shown in FIG. 11, the image processing unit 62 deletes the image correction unit 27 and the correction data storage unit 28 from the image processing unit 15 of the first embodiment, and replaces the defect extraction unit 26 with a defect extraction unit. 26A.
The defect extraction unit 26A calculates defect part image data 205 in the same manner as the defect extraction unit 26 of the first embodiment, generates modulation data 209 based on the defect part image data 205, and sends it to the drive control unit 16. is there.
That is, the modulation data 209 is the same data as the modulation data 208 when the image correction unit 27 does not perform distortion correction in the first embodiment. This is obtained by a simple calculation process corresponding to the on / off state of the mirror 3B.

Similar to the projection optical system 51, the projection optical system 51 A includes beam splitters 6 and 8, an imaging lens 7, and an objective lens 9, but the beam splitter 6 is disposed between the imaging lens 7 and the beam splitter 8. The difference is that the optical path branching position with respect to the CCD 13 is changed.
The imaging lens 70 is arranged between the CCD 13 and the beam splitter 6 according to the movement of the arrangement position of the beam splitter 6, is reflected from the processing surface 10 a and reaches the beam splitter 6, and is reflected by the beam splitter 6. It is a lens for forming the imaged light on the imaging surface of the CCD 13.

The distortion correction element 60 is an optical element arranged in the optical path of the projection optical system 51A in order to correct the inclination of the image plane of the projection optical system 51A generated according to the inclination of the micromirror array surface 3A.
The correction element driving unit 61 controls the correction amount of the distortion correction element 60 in accordance with the tilt angle information 207 from the rotation control unit 23.
Such a distortion correction element 60 can be realized by various optical actions such as refraction, diffraction, reflection, etc., and the correction element driver 61 determines the degree of the action according to each optical action. A means to change according to is adopted.

As the distortion correction element 60, for example, by changing the optical path length until the light enters the imaging lens 7 according to the inclination of the micromirror array surface 3A, the image surface after passing through the imaging lens 7 does not rotate. An optical element can be employed. As such an optical element, it is possible to employ a wedge-shaped prism element that is held so as to be able to advance and retreat with respect to the optical axis of the projection optical system 51A and to rotate in three axes. In this case, the processed reflected light 4 is combined with a light beam equivalent to that reflected on the surface orthogonal to the optical axis by changing the optical path length according to the transmission position of the wedge-shaped prism element. The light can enter the image lens 7.
The correction element driving unit 61 can employ a combination of an appropriate moving stage, rotation, and rotation stage. Then, according to the inclination of the micromirror array surface 3A obtained from the inclination angle information 207, the position and orientation for optimizing the correction of the optical path length are calculated, and the distortion correction element 60 is moved. When the micromirror array surface 3A is in a positional relationship orthogonal to the optical axis of the projection optical system 51, it is not necessary to use the distortion correction element 60, and therefore it is retracted from the optical path.

The distortion correction element 60 is not limited to such a prism element that changes the optical path length, and may include a hologram element, a refractive index distribution element, a liquid crystal lens, a filter, or a combination thereof. Further, the optical element is not limited to an optical element that does not have power. For example, an optical element that has power may be arranged eccentrically, or an optical element that can change power according to the light transmission position may be employed. May be.
Further, the position where the distortion correcting element 60 is disposed is also different from that in FIG. 10, such as between the imaging lens 7 and the objective lens 9 or between the objective lens 9 and the processing surface 10 a as necessary. You may arrange.
Also, the configuration of the correction element driving unit 61 can adopt a required driving form according to the configuration, and is not limited to the moving operation by the moving stage or the like. For example, a mechanism in which a plurality of distortion correction elements 60 are prepared and switched in the optical path as necessary can be employed. Alternatively, the distortion correction element 60 may be composed of a plurality of elements, and the correction operation may be performed by changing the interval or relative position thereof.

According to such a configuration, when step S1 of the first embodiment is completed, the correction element driving unit at the timing until step S7 is executed based on the acquired tilt angle information 207. 61, the distortion correction element 60 is adjusted. Step S6 is omitted according to the deletion of the image correction unit 27. Other operations can be performed in the same manner as in the first embodiment.
In the present embodiment, the distortion correction element 60 and the correction element driving unit 61 constitute an irradiation deviation correction unit.

  In this embodiment, the distortion correction element 60 optically corrects the rotation of the image plane due to the inclination of the micromirror array surface 3A. Therefore, the modulation data 209 is generated based on the defect image data 205, and the first The calculation process performed by the image correction unit 27 of the embodiment can be omitted. Therefore, the apparatus is simplified, the calculation processing time is reduced, and the laser processing step can be performed efficiently.

[Third Embodiment]
A laser processing apparatus according to the third embodiment of the present invention will be described.
FIG. 12 is a schematic device configuration diagram showing a schematic configuration of a laser processing apparatus according to the third embodiment of the present invention.

  As shown in FIG. 12, the laser processing apparatus 120 of the present embodiment includes an image processing unit 62 similar to that of the second embodiment, instead of the image processing unit 15 of the laser processing apparatus 100 of the first embodiment. A beam splitter 65, an inclination imaging means 63 (imaging means), and an inclination control unit 64 (imaging surface rotating means). The following description will focus on the differences from the first and second embodiments.

The beam splitter 65 branches the light branched by the beam splitter 6 in two directions. For example, a half mirror can be used.
In the present embodiment, the CCD 13 is disposed in the optical path reflected by the beam splitter 65, and the tilt imaging means 63 is disposed in the optical path that passes through the beam splitter 65.
Here, the CCD 13 is disposed on the imaging surface of the imaging lens 7.

  The tilted imaging means 63 is an imaging means in which the imaging surface can be tilted in the biaxial direction with respect to the imaging surface of the imaging lens 7. For example, a configuration in which an imaging element such as a CCD is held on a rotating stage that rotates in two axial directions can be employed. For example, when a CCD is employed, a configuration similar to that of the CCD 13 can be employed. Alternatively, an imaging optical system with an appropriate magnification may be disposed in the optical path after the light branched by the beam splitter 65 forms a real image, and re-imaging may be performed on the imaging surface of the CCD 13.

The tilt control unit 64 performs control to change the tilt of the imaging surface of the tilt imaging unit 63 according to the tilt angle information 207.
For example, when the center of the imaging surface is located on the imaging surface of the imaging lens 7, the imaging surface is set to an inclination equivalent to the inclination angle and inclination direction of the micromirror array surface 3A.
When imaging is performed via the imaging optical system, the tilt angle corresponding to the micromirror array surface 3A is set in consideration of the optical characteristics of the imaging optical system.
In the present embodiment, the tilt imaging unit 63 and the tilt control unit 64 constitute an irradiation deviation correction unit.

According to such a configuration, when step S1 of the first embodiment is completed, the tilt control unit 64 is at a timing until step S3 is executed based on the acquired tilt angle information 207. By rotating the tilt imaging means 63, an image of the processing surface 10a is picked up in a tilted state corresponding to the micromirror array surface 3A.
In this state, the imaging signal 200 is sent to the image processing unit 62. Then, from step S3 in FIG. 7, in accordance with the deletion of the image correction unit 27, step S6 is omitted, and the other operations are the same as those in the first embodiment.
Here, the normal image data 202 and defect information 204 used in steps S4 and S5 are stored in advance in the data storage unit 29 according to the inclination of the micromirror array surface 3A.
On the other hand, the image data of the processed surface 10 a captured by the CCD 13 without tilting the imaging surface is displayed on the monitor 12. Therefore, the operator can perform operations such as operation and confirmation of the repair state by observing the image of the processing surface 10a viewed from the optical axis direction of the projection optical system 51 in step S2 and step S9. .

In the present embodiment, the tilted imaging unit 63 captures the imaging surface used for imaging for generating modulation data in a tilted state corresponding to the micromirror array surface 3A, so that it is the same as in the second embodiment. The modulation data 209 can be obtained by a simple calculation process in which the luminance data of the defect image data 205 calculated by the defect extraction unit 26A is made to correspond to the on / off state of the micromirror 3B.
Therefore, since the arithmetic processing performed by the image correction unit 27 of the first embodiment can be omitted, the apparatus is simplified, the arithmetic processing time is reduced, and the laser processing step can be performed efficiently. .

  In the above description, when switching the wavelength of the laser light, the example in which the specular reflection direction and the diffraction direction coincide with each other has been described. However, the specular reflection direction and the diffraction direction indicate that the diffraction direction is a space in the projection optical system. It only needs to be approximately the same as the NA range on the modulation element side.

  In the above description, when the wavelengths are different from each other, the specular reflection direction and the diffraction direction are matched with each other according to each wavelength.For example, when a plurality of wavelengths used for processing are determined, A direction in which the diffraction directions coincide at each wavelength may be obtained, and the common diffraction direction and the regular reflection direction may be matched. In this case, since it is not necessary to change the inclination of the reference plane with respect to the optical axis of the projection optical system between laser processing steps using a plurality of wavelengths, efficient laser processing can be performed.

Further, in the above description, the example in which the spatial modulation element is tilted to match the specular reflection direction and the diffraction direction has been described. However, the present invention is not limited to such an application. This is also suitable when the spatial modulation element is tilted for the reasons described above. Therefore, the wavelength of the laser light source is not limited to a plurality, and may be one wavelength.
The plurality of wavelengths are not limited to two wavelengths, and may be switched to two or more wavelengths.
In addition, if the normal of the reference surface of the spatial modulation element is inclined with respect to the optical axis of the projection optical system, the present invention may be applied when the inclination is not variable. That is, it is good also as a structure which is not provided with the rotation mechanisms 21 and 22. FIG.

In the above description, the example in which the inclination of the reference surface of the spatial modulation element is acquired from the modulation element rotation mechanism has been described. However, the inclination from other control means for setting the rotation amount of the modulation element rotation mechanism Information on the angle may be acquired, and for example, an inclination angle detection unit such as a sensor for detecting the inclination angle of the spatial modulation element may be provided.
In addition, a means for capturing an image of the spatial modulation element may be provided, and the tilt angle may be obtained by calculating a distortion amount of a mark or the like serving as a position reference on the image.
Further, it is possible to make it possible to confirm the irradiation region in which the irradiation deviation correction has been performed before processing with the processing light source 1 as a configuration capable of irradiation using visible laser light from the light source unit 50 as guide light.

  In the above description of the second embodiment, an example in which the distortion correction element 60 is controlled by the correction element driving unit 61 has been described. However, the present invention is not limited to this, and according to the inclination of the reference plane. Alternatively, different correction elements may be exchanged.

  In the description of the third embodiment, the CCD 13 can display an image when the imaging surface is not tilted by the CCD 13. However, the CCD 13 can be omitted. Even in this case, it is possible to display the processed surface 10a in the same manner as the CCD 13 by connecting the tilt imaging means 63 to the monitor 12 and returning the tilt of the imaging surface by the tilt control unit 64 in steps other than step S3. It becomes.

  In the above description of the third embodiment, the normal image data 202 and the defect information 204 have been described by way of example in accordance with the inclination of the micromirror array surface 3A. In the comparison calculation process performed in step S3 and the defect extraction process performed in the defect extraction unit 26A, the normal image data 202 and the defect information 204 when the micromirror array surface 3A used in the first embodiment is not tilted are stored in advance. In accordance with the corner information 207, the normal image data 202 and the defect information 204 may be configured to perform arithmetic processing for converting the image data and information when the inclination occurs, respectively.

  In the description of the third embodiment, the tilt imaging unit 63 includes an image sensor such as a CCD, and the tilt control unit 64 rotates the imaging surface. An optical element that generates a geometric distortion that rotates the imaging surface of the imaging lens 7 so as to be inclined with respect to the imaging surface, such as a prism or a hologram element, is interposed between the imaging lens 7 and the imaging device. It is good also as a structure which comprises, and the inclination control part 64 performs control which makes such an optical element advance or retreat in an optical path, or changes a rotation amount.

  In addition, the constituent elements described in all of the above-described embodiments and modifications can be implemented in appropriate combination as much as technically possible within the scope of the technical idea of the present invention.

It is a typical device block diagram which shows schematic structure of the laser processing apparatus which concerns on the 1st Embodiment of this invention. FIG. 2 is a schematic cross-sectional view showing a cross-sectional configuration of a spatial modulation element and a state of diffracted light of the laser processing apparatus according to the first embodiment of the present invention, and a schematic cross-sectional view showing a state of diffracted light when the spatial modulation element is tilted. is there. It is a functional block diagram explaining schematic structure of the image processing unit of the laser processing apparatus which concerns on the 1st Embodiment of this invention. It is an example of the image of the to-be-processed surface in the laser processing apparatus which concerns on the 1st Embodiment of this invention. It is an example of the image of the to-be-processed surface which does not have the part which laser-processes similarly. It is an example of the difference image which took the difference of the image of the to-be-processed surface of FIG. 4, and the image of FIG. It is a flowchart explaining operation | movement of the laser processing apparatus which concerns on the 1st Embodiment of this invention. It is the schematic diagram explaining the shift | offset | difference of the irradiation range of the modulated light generate | occur | produced on a to-be-processed surface, and its enlarged view. It is a schematic diagram which shows the irradiation range corresponding to the corrected modulation data which the irradiation deviation correction | amendment means of the laser processing apparatus which concerns on the 1st Embodiment of this invention forms. It is a typical apparatus block diagram which shows schematic structure of the laser processing apparatus which concerns on the 2nd Embodiment of this invention. It is a functional block diagram explaining schematic structure of the image processing unit of the laser processing apparatus which concerns on the 2nd Embodiment of this invention. It is a typical apparatus block diagram which shows schematic structure of the laser processing apparatus which concerns on the 3rd Embodiment of this invention. It is an angle distribution figure for demonstrating an example of the angle distribution of the diffracted light in the laser processing apparatus which can switch a wavelength.

Explanation of symbols

1 Processing light source (laser light source)
2 Illumination optical system 3 Micro mirror array (spatial modulation element)
3A Micro mirror array surface (reference surface)
3B, 3a, 3b, 3c, 3e Micro mirror (modulation element)
4 Reflected light for processing (modulated light)
7, 70 Imaging lens 9 Objective lens 10 Work piece 10a Work surface 11 Observation light source 13 CCD
14 Moving stages 15, 62 Image processing unit (modulation data generator)
16 Drive control unit 20a Laser beam 21 rotation mechanism (modulation element rotation mechanism)
22 Rotating mechanism (Light source rotating mechanism)
23 Rotation control unit (Rotation mechanism control unit)
24 Image capturing unit 25 Image comparing unit 26 Defect extracting unit 27 Image correcting unit (irradiation deviation correcting means)
28 correction data storage unit 29 data storage unit 30b defective portion image 40B irradiation range 50 light source unit 51 projection optical system 60 distortion correction element (correction element)
61 Correction element driving unit 63 Tilt imaging means (imaging means)
64 Tilt control unit (imaging surface rotating means)
100, 110, 120 Laser processing device 206 Distortion correction information 207 Inclination angle information 208, 209 Modulation data

Claims (8)

A laser light source for generating laser light;
A spatial modulation element that spatially modulates the laser light generated by the laser light source with a plurality of modulation elements regularly arranged on a reference plane;
A projection optical system that projects the modulated light spatially modulated by the spatial modulation element onto a workpiece;
A modulation data generating unit that images the processing surface and generates modulation data for driving the spatial modulation element from the image of the processing surface;
Laser processing comprising: an irradiation deviation correcting means for correcting deviation of an irradiation range on the processing surface of the modulated light generated according to an inclination of the reference surface with respect to an optical axis of the projection optical system apparatus. The irradiation deviation correction means is
By performing image processing that eliminates the deviation of the irradiation range in accordance with the distortion of the image of the modulated light caused by the inclination of the reference surface with respect to the optical axis of the projection optical system, on the captured image of the processing surface The laser processing apparatus according to claim 1, wherein the modulation data is generated. The irradiation deviation correction means is
In the optical path between the spatial modulation element and the processing surface, distortion of the image of the reference surface projected on the processing surface is caused according to the inclination of the reference surface with respect to the optical axis of the projection optical system. The laser processing apparatus according to claim 1, further comprising a correction element that optically corrects. The irradiation deviation correction means is
An image pickup means for picking up an image of the processing surface; and an image pickup surface rotating means for rotating the image pickup surface of the image pickup means,
Based on the image picked up on the rotated imaging surface by rotating the imaging surface of the imaging means by the imaging surface rotating means according to the inclination of the reference surface with respect to the optical axis of the projection optical system. The laser processing apparatus according to claim 1, wherein the deviation of the irradiation range is corrected by generating the modulation data.   The laser processing apparatus according to claim 1, further comprising a modulation element rotating mechanism that tilts the spatial modulation element with respect to an optical axis of the projection optical system.   The diffraction direction of the modulation light is calculated from the rotation position of the modulation element rotation mechanism and the wavelength of the laser light, and the modulation element rotation is performed so that the diffraction direction substantially coincides with the optical axis of the projection optical system. The laser processing apparatus according to claim 1, further comprising a rotation mechanism control unit that drives the mechanism. The laser light source is generated so that two or more different wavelengths of laser light can be switched,
The laser processing apparatus according to claim 6, wherein the rotation mechanism control unit substantially aligns the optical axis of the projection optical system with a diffraction direction common to the wavelengths of the respective laser beams. . The spatial modulation element is
8. The micro mirror array comprising a plurality of micro mirrors that switch the tilt angle with respect to the reference plane and deflect the laser light in at least two directions as the plurality of modulation elements. The laser processing apparatus as described in.

Images