JP2008049361A - Beam forming method, and laser beam machining apparatus using the method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a beam forming method and a laser beam machining apparatus using the method capable of forming laser beams having a uniform beam profile in a predetermined shape, and realizing the laser beam machining of a workpiece with high precision by using the formed laser beams. <P>SOLUTION: The beam forming method for forming circular laser beams in a predetermined shape comprises: an elliptical shape forming step of forming laser beams of an elliptical shape from laser beams of a circular shape; a branching step of branching the laser beams of the elliptical shape to be obtained by the elliptical shape forming step; a turning step of turning the laser beams of at least one elliptical shape so that the angles of the elliptical shapes to be obtained by the branching step are made different from each other; a combining step of combining laser beams of the elliptical shape to be obtained by the turning step; and a segmenting step of segmenting laser beams of the predetermined shape by passing the composite laser beam obtained by the combining step through a mask mechanism. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a beam forming method and a laser processing apparatus using the method, and in particular, forms a laser beam having a uniform beam profile in a predetermined shape, and uses the formed laser beam to apply to a workpiece. The present invention relates to a beam forming method for realizing high-precision laser processing on a workpiece to realize high-precision laser processing, and a laser processing apparatus using the method.

2. Description of the Related Art Conventionally, there is a technique for performing laser processing by irradiating an object to be processed such as a printed wiring board with one or a plurality of laser beams using a laser beam generated from a laser oscillator. For example, the amount of light of a pulsed laser beam emitted from a CO ₂ gas laser oscillator is adjusted by a mask mechanism or the like, and focused on a processing point of an object to be processed by an imaging lens or the like.

  At this time, the laser beam that has passed through the light amount adjustment mechanism such as a mask is irradiated onto a predetermined region of the object to be processed through a uniform optical system (incident condensing lens, kaleidoreflector, etc.).

  In the above-mentioned uniform optical system, for example, a laser beam collected by an incident condenser lens is incident on a kaleidoreflector. (Energy) Intensity distribution (beam profile) is made uniform. A technique for controlling the beam profile of the laser beam includes, for example, a homogenizer.

  Then, the laser beam whose light intensity distribution is made uniform by the uniform optical system is shaken by, for example, a scanning system such as a galvano scanner, and is irradiated onto a predetermined region of the workpiece on the XY stage.

  By the way, in the laser processing described above, when the light intensity distribution of the laser beam is Gaussian (hanging), the light intensity distribution at the axis of the laser beam is the strongest and the light intensity distribution at the outer periphery of the laser beam is weak. Become.

  Further, when the mask mechanism is used as described above, for example, even when the beam diameter of the laser beam is regulated by the hole diameter of the fixed mask, the light intensity distribution near the axis of the laser beam that has passed through the fixed mask is the strongest. does not change. For this reason, the inner periphery of the hole processed (via hole processing) becomes tapered, and there is a problem that there is a limit to the improvement of the aperture ratio of the hole processing.

Therefore, conventionally, an opening made up of a plurality of holes or a plurality of slits is arbitrarily arranged in the mask mechanism, and the mask is rotated about the optical axis of the laser beam, whereby the light intensity distribution of the laser beam (beam A method for controlling the amount of light so that the profile is uniform is disclosed (for example, see Patent Document 1).
JP 2005-118831 A

  However, as described above, in the prior art, the light intensity distribution (beam profile) of the incident laser beam is adjusted to be uniform by rotating the mask, but it is necessary to control the rotation of the mask. The loss of the laser beam due to the rotating mask is large and not efficient.

  Furthermore, the laser beam emitted from the laser oscillator is usually circular. However, when processing a workpiece with a uniform beam profile by shaping the laser beam into a predetermined shape such as a quadrangle, for example, the laser beam is used as described above. A method of cutting out a laser beam having a predetermined shape by passing a rectangular slit or the like formed in the mask is used. However, when this method is used, the center portion of the cut laser beam is strong and the peripheral portion is weak, and the corner (corner) portion of the slit far from the central axis is particularly weak. For this reason, high-precision laser processing cannot be realized for the workpiece.

  For example, as a laser processing apparatus, there is an apparatus that performs laser patterning by irradiating a predetermined region of a processing object with a laser beam using a galvano scanner or the like. In this apparatus, an optical system is used that has a long distance from the galvano scanner to the object to be processed and generally transfers a shape having a corner to the processing point of the object to be processed. There are some limitations.

For example, the size of the galvano scanner is limited, and the NA (Numerical Aperture) of the processing point is limited in the spread angle θ so as to satisfy the standard of “M ² = πdθ / 4λ” indicating the laser quality. Further, in order to obtain a desired spot size (for example, 100 μm, etc.) of the laser beam irradiated to the above-described workpiece, a certain or higher beam quality M ² is required.

Therefore, in order to obtain a uniform processing point profile, since the beam profile with the laser oscillator is likely to be reflected in the machining point, for example without using the homogenizer, fiber, Callide reflector or the like, the configuration to deteriorate the beam quality M ² Is preferred.

  Therefore, in order to improve the uniformity of the laser beam, only the center portion of the laser beam is cut out at the slit surface, and in that case, the efficiency is deteriorated. Therefore, high-precision laser processing on the workpiece has not been realized.

  The present invention has been made in view of the above-described problems, and forms a laser beam having a uniform beam profile in a predetermined shape, and uses the shaped laser beam to provide a highly accurate laser on a workpiece. It is an object of the present invention to provide a beam forming method for realizing processing and a laser processing apparatus using the method.

  To achieve the above object, the present invention provides a beam shaping method for shaping a circular laser beam into a predetermined shape, and an elliptical shaping step of shaping an elliptical laser beam from the circular laser beam; A branching step for branching the elliptical laser beam obtained by the elliptical shaping step, and a rotating step for rotating at least one elliptical laser beam so that the angles of the respective elliptical shapes obtained by the branching step are different. A synthesis step for synthesizing the elliptical laser beam obtained by the rotation step, and a cutting step for cutting out the laser beam having a predetermined shape by passing the synthesized laser beam obtained by the synthesis step through a mask mechanism. It is characterized by that. Thereby, a uniform beam profile in a predetermined shape can be acquired. In addition, using the shaped laser beam, it is possible to realize high-precision laser processing on a workpiece.

  Further, in the rotating step, the elliptical laser beam is rotated so that the major axis of the elliptical shape intersects with at least one corner of the opening formed in the mask mechanism. Thereby, unnecessary loss due to the mask can be eliminated, and a uniform beam profile can be formed in the central portion and the peripheral portion in the predetermined shape.

  Further, the branching step splits the elliptical laser beam into a plurality based on the number of angles of the aperture using a polarizing optical system, and the combining step splits the elliptical laser beam split using the polarizing optical system. The laser beam is synthesized. Thereby, since the laser beam is branched and synthesized by the polarization optical system, it is possible to minimize degradation of the beam quality.

  The present invention also provides a laser processing apparatus for performing predetermined processing on a workpiece using a beam forming method for forming a circular laser beam into a predetermined shape, and a laser oscillator for irradiating the laser beam, and the laser oscillator Ellipse-shaped shaping means for shaping an elliptical laser beam from the circular laser beam emitted from the beam, branching means for branching the elliptical laser beam obtained by the elliptical-shaped shaping means, and each of the branching means obtained Rotating means for rotating at least one elliptical laser beam, synthesizing means for synthesizing the elliptical laser beam obtained by the rotating means, and synthesized by the synthesizing means so that the angles of the elliptical shapes are different. And a mask mechanism for cutting the laser beam into a predetermined shape. Thereby, a uniform beam profile in a predetermined shape can be acquired. In addition, using the shaped laser beam, it is possible to realize high-precision laser processing on a workpiece.

  Further, the rotating means rotates the elliptical laser beam so that the major axis of the elliptical shape intersects with at least one corner of the opening formed in the mask mechanism. Thereby, unnecessary loss due to the mask can be eliminated, and a uniform beam profile can be formed in the central portion and the peripheral portion in the predetermined shape.

  Further, the branching unit has a polarization optical system for branching the elliptical laser beam into a plurality based on the number of angles of the opening, and the combining unit is a polarization for combining the branched elliptical laser beam. It has an optical system. Thereby, since the laser beam is branched and synthesized by the polarization optical system, it is possible to minimize degradation of the beam quality.

  According to the present invention, it is possible to acquire a uniform beam profile in a predetermined shape. In addition, using the shaped laser beam, it is possible to realize high-precision laser processing on a workpiece.

<Concept of the present invention>
In the present invention, when a uniform beam profile of a laser beam is formed, an elliptical beam (long beam) that can be easily formed by an optical system or the like is used. Further, the shaped elliptical beam is branched into a predetermined number. Further, at least one elliptical beam is rotated about the center of the beam so that each of the branched elliptical beams has a different angle. Further, the elliptical beams that have been rotated are combined so that their centers intersect, and then passed through the mask. Thereby, unnecessary loss due to the mask can be eliminated, and a beam profile having a uniform central portion and peripheral portion in a predetermined shape can be obtained.

  In the present invention, when the elliptical beam is rotated, the long axis of the ellipse is positioned so as to intersect at least one corner (corner) of a predetermined shape formed by an opening (slit or the like) formed in the mask. Is preferred.

  With this technique, for example, in a processing apparatus that performs laser patterning processing with a long distance (work distance) from a laser oscillator to a processing object using a galvano scanner or the like, without reducing the beam quality of the laser beam emitted from the laser oscillator In addition, high-precision laser processing is realized on a workpiece using a shaped laser beam with a beam profile of the processing point corresponding to a uniform slit shape without deteriorating the transmission efficiency in the optical system. can do. Thereby, processing quality can be improved.

<Example of laser beam>
Here, an example of a laser beam incident on an opening formed in a mask mechanism for shaping a beam having a predetermined shape will be described with reference to the drawings. FIG. 1 is a diagram illustrating an example of a laser beam incident on an opening formed in a mask mechanism.

  In FIG. 1, a square slit is formed as an example of the opening. FIG. 1 (a) shows an example of a conventional laser beam incident on the slit, and FIG. 1 (b) shows an example of the laser beam of the present invention incident on the slit. In FIGS. 1A and 1B, ripple-shaped beam shapes having different sizes are shown. This indicates the strength of the beam profile, and the beam becomes stronger toward the center. Yes.

  As shown in FIG. 1A, since a conventional laser beam incident on a square slit 11 for shaping a beam having a predetermined shape is a circular laser beam (circular beam 12), a slit is formed. The beam profile of the laser beam cut out by 11 is a beam having a strong center and a weak peripheral part in the slit 11. Therefore, the corner portion of the slit 11 is the weakest beam because the distance from the center is long.

  Therefore, in the present invention, as shown in FIG. 1B, the laser beam incident on the slit 11 is first formed into an elliptical laser beam, and the elliptical beam is branched to have different directions. , One or both elliptical beams are rotated about the center of the elliptical shape, and the respective elliptical beams are combined so that the centers intersect, and the center of the combined elliptical beam 13 intersects the center of the slit 11. By passing through the slit 11, the beam profile of the laser beam in the peripheral portion in the slit 11 can be strengthened. Therefore, the profile in the processing spot is made uniform, and the processing quality can be improved.

  In the present invention, the shaped elliptical beam 13 is preferably rotated in accordance with the shape of the slit. Specifically, the elliptical beam is rotated so that the major axis of the elliptical shape is positioned at a position where it intersects the position of at least one corner (corner) of the slit shape. Thereby, the beam profile of the peripheral part of the beam shape | molded by the slit 11, especially a corner | angular part can be strengthened. Therefore, the beam profile can be made uniform.

  Here, FIG. 2 is a diagram showing another example of a laser beam incident on the slit in the present invention. For example, as shown in FIG. 2A, in the case of the rectangular slit 21, the elliptical beams 22-1 and 22-2 are arranged so that the major axis of the elliptical beam corresponds to each corner (corner) of the rectangle. Rotate. As shown in FIG. 2B, for example, in the case of a hexagonal slit 23, the major axes of the three elliptical beams 24-1 to 24-3 intersect with the corners of the hexagonal slit 23, respectively. 2 and combining the rotated elliptical beams 24-1 to 24-3 as shown in FIG. 2B, a laser beam having a uniform beam profile can be formed. Moreover, by irradiating the workpiece with the formed laser beam and processing it, it is possible to realize high-precision laser processing on the workpiece.

  Each elliptical beam described above is positioned so that the major axis intersects with two corners of the slit. However, the present invention is not limited to this, and is positioned so that the major axis intersects with at least one corner. It only has to be. Therefore, in addition to the slit shape described above, for example, a triangle or a star may be used, and a slit such as a rhombus or an ellipse may be split into a predetermined number of elliptical beams so as to correspond to the respective corners. A uniform beam profile can be obtained by passing the slit using an elliptical beam synthesized by rotating to an angle.

  Here, in the above-described embodiments, it is preferable to use a lens optical system in order to reduce loss when forming an elliptical beam. For example, a cylindrical lens that can realize optical systems having different magnifications in the vertical and horizontal directions is used. Can do. Thereby, an elliptical beam can be easily shaped by the incidence of a circular beam. The method for forming the elliptical beam is not limited to this in the present invention.

  When the elliptical beam is branched, a polarization optical system such as a beam splitter can be used as the branching unit. The splitter is preferably a half mirror or a polarizing beam splitter. In addition, when branching into a P wave and an S wave with a polarization beam splitter, the branching ratio can be easily adjusted by using a λ / 2 wavelength plate or a λ / 4 wavelength plate.

In addition, when the branched elliptical beam is rotated by a predetermined angle and the rotated elliptical beam is synthesized, the polarization optical system can be used as the synthesizing unit similarly to the branching unit. For example, when a polarization beam splitter is used as a branching unit, a combined polarization beam splitter that combines P waves and S waves is used. In PS synthesis by the synthesis polarization beam splitter, for example, a λ / 2 wavelength plate is inserted for PS synthesis to adjust the direction of linearly polarized light. In this way, since the laser beam is branched and synthesized by the polarization optical system, deterioration of the beam quality can be minimized. Further, since there is no change in the beam quality (M ² , divergence angle θ) of the combined beam, there is little loss in the optical system. Therefore, a highly accurate laser beam can be formed.

  In addition, when rotating an elliptical beam, the elliptical beam is rotated to a predetermined angle by using the polarizing optical system or mirror unit described above to incline and reflect at a predetermined angle with respect to the incident direction of the laser beam. Let

  Note that the configuration for branching, rotating, and synthesizing the laser beam is not limited to the above-described content, and other configurations may be used.

<Laser processing equipment>
Next, a laser processing apparatus that performs laser processing by irradiating an object to be processed using a laser beam formed by the method described above will be described with reference to the drawings. As for the laser processing apparatus shown below, an example will be described in which two elliptical beams are combined and passed through a rectangular slit, and the object to be processed is irradiated with a uniform beam profile. In the invention, the slit shape and the like are not limited to this.

  FIG. 3 is a diagram showing a configuration example of a laser processing apparatus that performs processing by beam forming in the present invention. 3 includes a control means 31, a laser oscillator 32, a galvano scanner 33, a galvano mirror 34, a stage driver 35 as a stage driving means, a stage 36, and an elliptical shaping means. A cylindrical lens 37, a beam splitter 38 which is a polarization optical system as a branching unit, mirror units 39-1 to 39-3 as a rotation unit, a combined polarization beam splitter 40 which is a polarization optical system as a combining unit, A slit 41 that is an opening as a mask mechanism and a slit imaging optical system 42 are provided. 3A to 3G schematically show the shape of the laser beam at that time.

  In the laser processing apparatus 30 shown in FIG. 3, the control means 31 controls the entire laser processing apparatus 30. Specifically, the control unit 31 sets processing conditions based on a processing plan parameter 52 including various control information that defines how the processing object 51 is processed, and a laser oscillator 32 and a galvano scanner 33. And corresponding control information (irradiation condition setting information, irradiation start information, settling information, stage target position information, etc.) are output to the stage driver 35.

  The laser oscillator 32 is irradiation condition setting information such as the frequency and power of the laser beam, the number of shots, the pulse width, the irradiation timing information, and the irradiation position for processing a predetermined processing region of the processing object 51 obtained from the control means 31. Based on the above, the laser beam irradiation conditions are set. Further, the laser oscillator 32 irradiates a predetermined laser beam based on the irradiation start information obtained from the control means 31.

Here, as the type of the laser beam, a normal laser beam such as a YAG laser, an excimer laser, or a CO ₂ laser can be used. In this embodiment, a YAG laser second high frequency (for example, wavelength 532 nm), laser intensity 80 W (for example, 8 mJ, 10 kHz, etc.), beam size diameter 5 mm, beam quality M ² = 20 is used as an example. The intensity of the laser beam in the present invention is not particularly limited.

  Next, the galvano scanner 33 moves and stabilizes the galvano mirror 34 to a predetermined position based on the setting information such as the position and angle of the galvano mirror 34 obtained from the control means 31, and is incident on the galvano mirror 34. The direction of the laser beam is changed to irradiate a predetermined processing position of the processing object 51. By using the galvano scanner 33, for example, the irradiation position of the laser beam with respect to the horizontal direction (XY direction) of the workpiece 51 can be changed, and the laser beam can be irradiated by irradiating a predetermined region (block).

  The stage driver 35 is for positioning the stage 36, which is obtained by fixing the workpiece 51 obtained from the control means 31, by suction or the like in a predetermined height (Z direction) and / or horizontal direction (XY direction) corresponding to the machining conditions. The stage 36 is moved based on the stage target position information.

  The cylindrical lens 37 changes the vertical and horizontal magnifications of the circular beam (FIG. 3A) emitted from the laser oscillator 32 and shapes an elliptical beam (FIG. 3B). The optical system for shaping the elliptical beam is not limited to the cylindrical lens, and other lens optical systems and configurations having a beam deformation mechanism can be used.

  The beam splitter 38 receives the elliptical beam (FIG. 3B) deformed by the cylindrical lens 37, branches the incident laser beam into, for example, a P wave and an S wave, and outputs the elliptical beam in a predetermined direction ( 3 (c)) The beam splitter 38 may be a half mirror, a polarization beam splitter, etc. When the beam splitter 38 is branched, a λ / 2 wavelength plate or a λ / 4 wavelength plate is used. By using it, the ratio of branching can be adjusted, and various branches can be realized.

  The mirror unit 39 guides the incident laser beam in a predetermined direction. At this time, the laser beam can be rotated by a predetermined angle according to the incident angle of the laser beam incident on the mirror unit 39 and output.

  Specifically, the mirror unit 39-1 and the mirror unit 39-2 shown in FIG. 3 reflect and guide each laser beam obtained from the beam splitter 38 in a predetermined direction. At this time, the mirror unit 39-2 can be rotated 90 ° in a predetermined direction by the mirror (FIG. 3D). The mirror unit 39-3 guides the combined laser beam from the combined polarization beam splitter 40 in a predetermined direction. At this time, as described above, the laser beam can be rotated by 45 ° by the mirror ((FIG. 3 (f)). The specific configuration of each of the mirror units 39-1 to 39-3 will be described later. To do.

  The combined polarization beam splitter 40 performs PS combining so that the centers of the elliptical beams of P waves and S waves obtained from the mirror units 39-1 and 39-2 intersect. That is, the combined polarization beam splitter 40 is arranged so that two elliptical beams of P wave and S wave propagate on the same optical axis. When performing PS synthesis, a λ / 2 wavelength plate is inserted into the optical system to adjust the direction of linearly polarized light.

  In this way, the laser beams are combined on the same optical axis and propagate on the same optical axis. Note that the power of the combined laser beam is a value obtained by adding the powers of the respective laser beams (FIG. 3E). In this way, by performing PS combining, there is no change in the beam quality of the combined beam, so that loss in the optical system can be reduced.

  The slit 41 is opened in a preset shape, and a laser beam having a desired shape can be obtained by allowing the laser beam to pass therethrough (FIG. 3G). In this embodiment, for example, a square having a side of 0.5 mm to 2 mm can be used as the slit size, and a reduction optical system of about 1/4 to 1/5 is formed with respect to the incident laser beam. However, the present invention is not limited to this. The slit imaging optical system 42 shapes the laser beam that irradiates the workpiece 51 by enlarging or reducing the laser beam that has passed through the slit 41 into a predetermined shape. For example, as an example, the beam shape is formed so that the processing size of the processing point of the processing object 51 is a square having a side of 100 μm to 500 μm.

  Next, specific operation contents based on the apparatus configuration shown in FIG. 3 will be described. First, a laser beam is emitted from the laser oscillator 32 under the control of the control means 31 (FIG. 3A), and an elliptical beam is shaped by the cylindrical lens 37 (FIG. 3B).

  The elliptical beam is split into two elliptical beams by the beam splitter 38 (FIG. 3C). The two branched elliptical beams are guided in a predetermined direction by the mirror units 39-1 and 39-2. At this time, the elliptical beams having different angles are transmitted by the mirror units 39-1 and 39-2. It becomes. Specifically, one of the branched elliptical beams is rotated 90 ° by the mirror unit 39-2 (FIG. 3D).

  Next, elliptical beams having different angles are combined by the combining polarization splitter 40 to form a crossed elliptical beam (FIG. 3E). Further, the obtained cross elliptical beam is rotated by 45 ° by the mirror unit 39-3 to form an X-shaped laser beam from the cross (FIG. 3 (f)) and guided in a predetermined direction.

  Next, a rectangular shape is cut out by the slit 41 (FIG. 3 (g)), the shape is reduced by the slit imaging optical system 42, is incident on the galvano mirror 34, and the laser beam shaken by the galvano mirror 34 is processed. A predetermined position of the object 51 is irradiated and laser processing is performed.

  Note that the number and installation position of the beam splitter 38, the mirror unit 39, and the combined polarization splitter 40 are arbitrarily set according to the number of branched laser beams, the rotation angle of each elliptical beam, and the like.

  In addition to the configuration of the above-described embodiment, for example, by applying a predetermined voltage to the laser beam emitted from the combined polarization beam splitter 40 using, for example, an electro-optic modulator, linearly polarized light passing therethrough is applied. The polarization direction may be rotated by a predetermined angle.

<Configuration example of mirror unit>
Here, FIG. 4 is a diagram illustrating a configuration example of the mirror unit in the present embodiment. In FIG. 4, the XY axis is shown as a plane axis perpendicular to the optical axis of the laser beam 60, and the cube 61 indicated by a dotted line clarifies the traveling direction of the laser beam 60 in three dimensions. Is for.

  Further, FIG. 4A shows a mirror unit corresponding to the above-described mirror unit 39-1, and FIG. 4B shows a mirror unit corresponding to the above-described mirror unit 39-2, and FIG. ) Shows a mirror unit corresponding to the above-described mirror unit 39-3.

  In the mirror unit 39-1, it is sufficient to reflect the laser beam 60 in a predetermined direction without rotating. Therefore, for example, the folding mirror 62 is installed at the position shown in FIG. 4A with respect to the traveling direction of the laser beam 60. By doing so, the laser beam 60 can be reflected without rotating (rotating 0 °).

  Further, in the mirror unit 39-2, it is necessary to rotate the laser beam 60 by 90 ° and reflect it in a predetermined direction. For example, the two folding mirrors 63 and 64 are arranged with respect to the traveling direction of the laser beam 60 in FIG. By installing at the position shown in b), the laser beam 60 can be reflected by being rotated by 90 °.

  Further, in the mirror unit 39-3, it is necessary to rotate the laser beam 60 by 45 ° and reflect it in a predetermined direction. For example, the two folding mirrors 65 and 66 are arranged with respect to the traveling direction of the laser beam 60 in FIG. By installing at the position shown in c), the laser beam 60 can be reflected by being rotated by 45 °.

  By selecting and installing one or more mirror units as shown in FIGS. 4A to 4C described above, one or more laser beams are rotated at an arbitrary angle around the center of the beam. be able to. Note that the shape, size, installation position, and the like of the folding mirror in the above-described mirror unit are not limited to this.

<Example of beam shape>
Here, FIG. 5 is a diagram illustrating an example of a beam shape in the present embodiment. 5A shows an example of a conventional beam shape, and FIG. 5B shows an example of a beam shape formed by the present invention. In addition, each region shown in the ripple shape in FIG. 5 indicates the magnitude of the laser intensity, and indicates that the intensity increases toward the center.

  As shown in FIG. 5 (a), in the case of a conventional circular beam, the intensity distribution also spreads in a circular shape, so that the intensity of the peripheral portion in the slit becomes uniform when cut out by a slit such as a square. In particular, the strength of corner portions such as squares is insufficient.

  Therefore, as shown in FIG. 5 (b), by using the elliptical beam composite shape in the present invention, the intensity of the peripheral portion in the slit can be made uniform even when cut out by a slit such as a square. A corner portion such as a square can have a sufficient strength for high-precision processing. Therefore, it is possible to form a laser beam having a uniform beam profile, and by irradiating the object to be processed with this laser beam, it is possible to realize highly accurate laser processing on the object to be processed.

As described above, according to the present invention, a uniform beam profile can be acquired in a predetermined shape. In addition, using the shaped laser beam, it is possible to realize high-precision laser processing on a workpiece. Specifically, beam quality deterioration can be minimized by shaping a circular beam into an elliptical beam, and branching and recombining the shaped laser beam with a polarizing optical system such as a splitter. Further, since there is no change in the beam quality (M ² , divergence angle θ) of the combined beam, the loss in the optical system can be reduced.

  Furthermore, according to the present invention, a beam profile suitable for a processing spot corresponding to the slit shape is obtained by rotating the long axis of the elliptical beam so as to match the corner of the slit shape as the opening of the mask mechanism. Can do. Furthermore, the processing quality can be improved by making the profile in the processing spot uniform.

  The laser processing in the present invention can be applied to all laser processing such as via formation, welding, cutting and annealing.

  The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to such specific embodiments, and various modifications can be made within the scope of the gist of the present invention described in the claims. Can be changed.

It is a figure which shows an example of the laser beam which injects into the opening part formed in the mask mechanism. It is a figure which shows the other example of the laser beam which injects into the slit in this invention. It is a figure which shows one structural example of the laser processing apparatus which processes by the beam shaping in this invention. It is a figure which shows the structural example of the mirror unit in a present Example. It is a figure which shows an example of the beam shape in a present Example.

Explanation of symbols

11, 21, 23, 41 Slit (opening)
DESCRIPTION OF SYMBOLS 12 Circular beam 13, 22, 24 Elliptic beam 30 Laser processing apparatus 31 Control means 32 Laser oscillator 33 Galvano scanner 34 Galvano mirror 35 Stage driver 36 Stage 37 Cylindrical lens 38 Beam splitter 39 Mirror unit 40 Synthetic polarization beam splitter 42 Slit imaging optics System 51 Processing object 52 Processing plan parameter 60 Laser beam 61 Cube 62-66 Folding mirror

Claims (6)

In a beam shaping method for shaping a circular laser beam into a predetermined shape,
An elliptical shaping step of shaping an elliptical laser beam from the circular laser beam;
A branching step for branching the elliptical laser beam obtained by the elliptical shaping step;
A rotating step of rotating at least one elliptical laser beam such that the angles of the elliptical shapes obtained by the branching step are different;
A synthesis step of synthesizing an elliptical laser beam obtained by the rotation step;
A beam forming method comprising: a step of cutting out a laser beam having a predetermined shape by passing the combined laser beam obtained by the combining step through a mask mechanism. The rotation step includes
The beam shaping method according to claim 1, wherein the elliptical laser beam is rotated so that the major axis of the elliptical shape intersects at least one corner of an opening formed in the mask mechanism. The branching step branches the elliptical laser beam into a plurality based on the number of angles of the opening using a polarization optical system,
3. The beam shaping method according to claim 1, wherein the synthesizing step synthesizes an elliptical laser beam branched using a polarization optical system. In a laser processing apparatus that performs predetermined processing on a workpiece using a beam forming method for forming a circular laser beam into a predetermined shape,
A laser oscillator for irradiating the laser beam;
Elliptical shaping means for shaping an elliptical laser beam from a circular laser beam emitted from the laser oscillator;
Branching means for branching the elliptical laser beam obtained by the elliptical shaping means;
Rotating means for rotating at least one elliptical laser beam so that the angles of the elliptical shapes obtained by the branching means are different;
Synthesizing means for synthesizing an elliptical laser beam obtained by the rotating means;
A laser processing apparatus comprising a mask mechanism for cutting out a synthesized laser beam obtained by the synthesizing means into a predetermined shape. The rotating means includes
5. The laser processing apparatus according to claim 4, wherein the elliptical laser beam is rotated so that the elliptical long axis intersects at least one corner of an opening formed in the mask mechanism. The branching unit has a polarization optical system for branching the elliptical laser beam into a plurality based on the number of angles of the opening,
6. The laser processing apparatus according to claim 4, wherein the synthesizing unit includes a polarization optical system that synthesizes a branched elliptical laser beam.

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