JP4318525B2 - Optical apparatus and laser irradiation apparatus - Google Patents

Description

  The present invention relates to an optical apparatus and a laser irradiation apparatus that can change the optical characteristics of laser light.

  There are cases where it is desired to change the spot diameter of laser light in drilling or drawing using laser light. For example, it is necessary to change the inner diameter of the hole to be formed or the line width of the drawing pattern. In such a case, the operation of the laser oscillator is once stopped. Then, an adjustment operation is performed such that the mask that defines the beam diameter of the laser beam is replaced with another mask, or the magnification of the lens is changed by moving the lens that condenses the laser beam in the optical axis direction.

  Patent Documents 1 and 2 disclose techniques that can change the beam diameter of laser light without requiring such adjustment work. In these techniques, the optical path of the laser light emitted from the light source is selectively switched to the first optical path or the second optical path. A mask is arranged on each optical path. The inner diameters of the pinholes formed in these masks are different from each other. By switching the optical path of the laser light emitted from the light source to the optical path where the desired mask is arranged, the beam diameter of the laser light can be changed to a desired value.

JP 2002-35979 A (FIG. 1) JP 2002-335063 A (FIG. 1)

  It is desired to emit laser light having a changed beam diameter along one optical axis. That is, it is desirable that the laser light passing through either the first optical path or the second optical path travel on the same optical path after the beam diameter is changed. In the techniques of Patent Documents 1 and 2, a polarization beam splitter is used as means for that purpose. However, in principle, the polarization beam splitter can only match the optical axis of P-polarized light with the optical axis of S-polarized light. Therefore, only the optical path through which the P-polarized light passes or the optical path through which the S-polarized light passes can be selected in advance as the optical path of the laser light emitted from the light source. That is, the laser beam diameter can be switched only in two stages.

  An object of the present invention is to make it possible to change optical characteristics such as the beam diameter of laser light in two or more steps or in a stepless manner, and to emit laser light whose optical characteristics have been changed along one optical axis. It is to provide the technology that can.

  In this specification, deflection refers to changing the traveling direction of laser light. The deflection angle refers to an angle formed by the incident direction of the laser light incident on the deflector and the emission direction of the laser light deflected by the deflector from the deflector. The deflection direction refers to the emission direction of the laser light deflected by the deflector from the deflector.

According to one aspect of the present invention,
A first deflector for deflecting laser light incident on a first deflection point along one incident optical axis at the first deflection point, and deflecting the laser light according to a control signal given from the outside A first deflector for changing the angle;
An optical system for causing the laser beam deflected by the first deflector to be incident on a common second deflection point via different optical paths depending on the deflection direction;
A second deflector for deflecting the laser beam incident on the second deflection point by the optical system at the second deflection point, the deflected laser beam traveling on a common outgoing optical axis; A second deflector that changes a deflection angle of the laser beam in accordance with a control signal given from the outside so as to propagate ;
Laser light disposed on the optical path between the first deflection point and the second deflection point through which the laser beam deflected by the first deflector passes, and deflected by the first deflector There is provided an optical apparatus comprising: an optical characteristic adjusting unit that varies the optical characteristic of each of the optical paths depending on the optical path through which the laser beam passes .

  According to another aspect of the present invention, incident laser light incident on a deflection point along one incident optical axis is deflected in a deflection direction determined according to a control signal given from the outside, while the incident laser light is deflected. When the laser beam is deflected, the laser beam incident on the deflection point in the direction opposite to the deflection direction is deflected as a return laser beam in the direction along the incident optical axis, and deflected by the deflector. An optical system for causing the incident laser light to enter the deflection point in a direction opposite to the deflection direction when deflected by the deflector after passing through different optical paths depending on the deflection direction; and the incident optical axis. There is provided an optical device including a separating unit that separates and extracts the return laser beam from a common optical path through which both the incident laser beam and the return laser beam pass.

  According to still another aspect of the present invention, there is provided a multi-reflecting surface body having a first reflecting surface and a second reflecting surface for deflecting both incident laser beams, wherein the laser is incident on the first reflecting surface. When the deflection angle of the light changes with the movement of the multi-reflecting surface body, the deflection angle of the laser light incident on the second reflecting surface changes by the same angle as the angle representing the amount of change. The multi-reflecting surface body configured as described above, and the laser light incident on the first reflecting surface along one incident optical axis and deflected on the first reflecting surface are made to pass through different optical paths according to the deflection directions. When the deflection angle of the laser beam on the first reflecting surface changes, the second reflecting surface is incident on the second reflecting surface by the same angle as the angle representing the amount of change. The incident direction of the laser beam incident on the reflective surface of the Optical device and an optical system configured to is provided.

  Since the spatial position of the optical path through which the laser beam incident along one incident optical axis is emitted along one outgoing optical axis can be moved, the optical path can be changed using various optical elements. In addition, the optical characteristics of the laser beam can be made different. Thereby, the optical characteristic of a laser beam can be changed in two steps or more or steplessly.

FIG. 1 shows a laser processing apparatus according to a first embodiment. The light source 1 emits laser light. The laser light emitted from the light source 1 is incident on the beam diameter switch 2 along one of the incident optical axis S _IN. Beam diameter switch 2 switches the beam diameter of the incident laser beam along an incident optical axis S _IN, emits along the laser light beam diameter is switched to one of the exit optical axis S _OUT.

The beam diameter switching device 2 will be described. The first galvanometer mirror 10 is disposed at a position where laser light traveling along the incident optical axis _SIN is incident. The incident position of the laser beam on the reflecting surface of the first galvanometer mirror 10 is the laser beam deflection point P ₁ in the first galvanometer mirror 10. The first parabolic mirror 11 is positioned to the deflection point P ₁ and the focal point. A second rotating parabolic mirror 12 is arranged so as to face the first rotating parabolic mirror 11. The second rotary parabolic mirror 12 has a rotational symmetry axis that coincides with the rotational symmetry axis of the first rotational parabolic mirror 11. The first rotary parabolic mirror 11 and the second rotary parabolic mirror 12 are both off-axis rotary parabolic mirrors.

A second galvanometer mirror 13 is disposed at the focal position of the second rotary parabolic mirror 12. The laser light deflection point P ₂ on the reflecting surface of the second galvanometer mirror 13 coincides with the focal point of the second rotary parabolic mirror 12. A beam diameter adjusting unit 15 is disposed between the first rotating parabolic mirror 11 and the second rotating parabolic mirror 12.

The first galvanometer mirror 10 is chosen the laser beam incident on the deflection point _{P 1} along the incident optical axis _{S IN} optical axis of the first through _{4 S 1, S 2, S} 3, and the _{S 4} Deflection in a direction along one optical axis. The first galvanometer mirror 10 oscillates according to the control signal sig ₁ given from the controller 14, thereby changing the deflection angle of the laser light incident on the deflection point P ₁ . Thus, it switched deflection direction of the laser beam incident on the deflection point P _1.

Each of the laser beams traveling along the first to fourth optical axes S ₁ , S ₂ , S ₃ , and S ₄ is incident on the reflection surface of the first paraboloidal mirror 11. The first rotary paraboloid mirror 11 receives first to fourth laser beams incident along the _first to fourth optical axes S ₁ , S ₂ , S ₃ , and S ₄ , which are parallel to each other. Reflected in a direction along the parallel optical axes SP ₁ , SP ₂ , SP ₃ , and SP ₄ . The beam diameter adjusting unit 15 makes the beam diameters of the laser beams traveling along the first to fourth parallel optical axes SP ₁ , SP ₂ , SP ₃ , and SP ₄ different from each other.

FIG. 2 shows a configuration of the beam diameter adjusting unit 15. Beam diameter adjusting part 15, parallel optical axes _SP 1 of the first to _4, SP 2, SP _3, and on the SP _4, a mask 15a respectively, 15b, 15c, and 15d are configured arranged. Each of the masks has a pinhole, and only the portion where the pinhole is formed allows the laser beam to pass. The beam diameter of the laser beam that has passed through the mask corresponds to the inner diameter of the pinhole formed in the mask. The inner diameters of the pinholes formed in the masks 15a, 15b, 15c, and 15d are different from each other. For example, the masks 15a, 15b, 15c, and 15d have pin holes with large inner diameters in this order.

Returning to FIG. 1, the description will be continued. Any laser light whose beam diameter is adjusted by the beam diameter adjusting unit 15 is incident on the reflecting surface of the second paraboloid mirror 12. The second rotary parabolic mirror 12 is configured to cause the laser light incident along the first to fourth parallel optical axes SP ₁ , SP ₂ , SP ₃ , and SP ₄ to enter the second galvanometer mirror from different directions. deflection point 13 to be incident on the _{P 2.}

The second galvanometer mirror 13, by swinging in accordance with the control signal sig ₂ given from the controller 14 to change the deflection angle of the laser beam incident on the deflection point P _2. Thus, the laser light incident from various directions to the deflection point P ₂ is deflected in the direction along the one of the exit optical axis S _OUT.

Specifically, the second galvanometer mirror 13, the laser first galvano mirror 10 is when changing the deflection angle of the laser beam by an angle identical to the angle indicating the amount of change, that is incident on the deflection point P ₂ Change the deflection angle of light.

On the other hand, when the first galvanometer mirror 10 changes the deflection angle of the laser beam, the optical system constituted by the pair of rotary parabolic mirrors 11 and 12 is the same angle as the angle representing the amount of change. The incident direction of the laser light incident on the deflection point P2 of the _second galvanometer mirror 13 is changed.

That is, when the first galvanometer mirror 10 changes the deflection angle of the laser beam, the incident direction of the laser beam incident on the deflection point P2 of the _second galvanometer mirror 13 changes. At the same time, the second galvanometer mirror 10 changes. mirror 13 changes the deflection angle of the laser beam incident on the deflection point P _2. Therefore, the laser beam incident on the deflection point P _2, the emission direction from the second galvano-mirror 13 is maintained in a direction along the one of the exit optical axis S _OUT.

More specifically, a pair of parabolic mirror 11 and the optical system constituted by 12 the laser beam deflected in the direction along the optical axis S _i of the i by the first galvanometer mirror 10, the outgoing light The light is incident on the deflection point P2 of the _second galvanometer mirror 13 from the direction in which the deflection angle with respect to the axis S _OUT is equal to the deflection angle with respect to the _i- th optical axis S _i from the incident optical axis S _IN . (Here, i is an arbitrary natural number of 1 or more and 4 or less.)
The second galvanometer mirror 13 is configured so that the deflection angle of the laser beam deflected by the second galvanometer mirror 13 is always equal to the deflection angle of the laser beam deflected by the first galvanometer mirror 10. It operates in synchronization with the first galvanometer mirror 10.

Therefore, the laser light incident from various directions to the deflection point P ₂ by a pair of parabolic mirrors 11 and 12 are deflected in the direction along the one of the exit optical axis S _OUT by the second galvanometer mirror 13 . The outgoing optical axis S _OUT is preferably arranged on the same straight line as the incident optical axis S _IN .

The laser light emitted along the outgoing optical axis S _OUT is incident on the surface of the substrate W _{1 to} be processed via the galvano scanner 3 and the fθ lens 4. The galvano scanner 3 scans the laser light emitted from the beam diameter switch 2 in a two-dimensional direction. The fθ lens 4 causes the scanned laser light to enter the surface of the substrate W ₁ to be processed substantially perpendicularly. Further, f [theta] lens 4, the mask 15a in the beam diameter adjusting unit 15, 15b, 15c, and 15d of the image of, connecting to the surface of the substrate to be processed _{W 1.} The substrate W _{1 to} be processed is held on the XY stage 5. XY stage 5 moves the position of the workpiece substrate W ₁ in the two-dimensional directions.

According to this laser processing apparatus, the space of the optical path through which the laser light incident on the beam diameter switching unit 2 along one incident optical axis S _IN passes along one output optical axis S _OUT. The target position can be different. Since the masks 15a, 15b, 15c, and 15d are respectively disposed on these optical paths, the beam diameter of the laser light emitted from the light source 1 can be switched in four stages. That is, it changes the spot diameter of the laser beam on the surface of the substrate to be processed W ₁ to 4 stages.

  The range in which the deflection angle can be changed in the first and second galvanometer mirrors 10 and 13 is about 30 degrees. This value is larger than other deflectors such as an acousto-optic deflector. Therefore, the optical path of the laser beam can be distributed in a wider space compared to the case where an acousto-optic deflection element or the like is used as a polarizer. Therefore, a larger number of masks can be arranged, so that the number of beam diameter switching can be increased.

  In this laser processing apparatus, the beam diameter switching order can be arbitrarily set. That is, the controller 14 can control the postures of the galvanometer mirrors 10 and 13 so that the beam diameter of the laser light emitted from the beam diameter switch 2 gradually becomes thicker or narrower. It is also possible to control the attitude of the galvanometer mirrors 10 and 13 so that the beam diameter of the laser beam emitted from the laser beam changes arbitrarily.

  In addition, as the galvanometer mirrors 10 and 13, a biaxial galvanometer mirror configured to be able to cover one reflection surface in the biaxial direction may be used. In the case of using a biaxial galvanometer mirror, a mask is distributed between the rotary parabolic mirrors 11 and 12 in a two-dimensional plane that intersects the rotational symmetry axis of the rotary parabolic mirrors 11 and 12. can do. Examples of the biaxial galvanometer mirror include a planar galvanometer mirror having a gimbal structure.

Figure 3 is a sectional view showing a main portion of a substrate to be processed W ₁ which is drilling with the laser machining apparatus. The substrate to be processed W ₁ is an intermediate body, for example a printed circuit board. The substrate to be processed W _1, to form a double hole (step via) 18.

First, the first galvano mirror 10 selects the direction along the fourth optical axis S ₄ as a deflection direction of the laser beam incident on the deflection point P _1. Thereby, the laser light emitted from the light source 1 passes through the mask 15d. At this time, the beam diameter of the laser light emitted from the beam diameter switcher 2 is maximized. The laser beam is incident on the surface of the substrate to be processed W _1, thereby ablating the incident location. Thereby, the hole 16 is formed.

Next, the first galvano mirror 10 of the deflection direction of the laser beam incident on the deflection point P _1, it switches to the first direction along the optical axis S _1. Thereby, the laser light emitted from the light source 1 passes through the mask 15a. At this time, the beam diameter of the laser beam emitted from the beam diameter switching unit 2 is minimized. This laser beam is incident on the central portion of the bottom surface of the hole 16 and ablate the incident location. Thereby, a hole 17 having an inner diameter smaller than the inner diameter of the hole 16 is formed. Thus, the double hole 18 whose side wall forms a step shape is completed.

By driving at least one of the galvanometer scanner 3 and the XY table 5, because it is possible to move the irradiation position of the laser beam on the surface of the substrate to be processed W _1, a plurality of dual substrate to be processed W ₁ Hole 18 can be formed.

Substrate to be processed W _1, it is assumed that a double hole 18 to the N form. N is, for example, thousands. In conventional processing methods, once on the workpiece substrate W _1, only the large hole 16 of the inner diameter to the N form. Next, after the operation of the laser oscillator is stopped, a mask replacement operation or the like is performed in order to change the beam diameter of the laser beam to be small. Then, a hole 17 having a small inner diameter is formed by irradiating the center portion of the bottom surface of each hole 16 with a laser beam whose beam diameter has been changed to be small. In the process of forming the N double holes 18, the mask can be replaced only once. However, in the process of completing one double hole 18, it is necessary to move the irradiation position of the laser beam. For this reason, the relative positional accuracy of the hole 16 having a large inner diameter and the hole 17 having a small inner diameter is affected by the scanning accuracy of the laser beam by the galvano scanner 3.

  On the other hand, in the present laser processing apparatus, the beam diameter can be quickly switched without requiring a mask replacement operation or the like, so that the processing efficiency is not impaired even if the beam diameter is switched N times. That is, the processing efficiency is not impaired even if the procedure of forming the hole 16 having a large inner diameter, switching the beam diameter, and forming the hole 17 having a small inner diameter is repeated N times. Since the galvano scanner 3 is fixed in the process of completing one double hole 18, the relative positional accuracy between the hole 16 having a large inner diameter and the hole 17 having a small inner diameter can be improved. As a result, it is possible to prevent a decrease in the manufacturing yield of the printed circuit board due to poor alignment or the like.

  In forming the double hole 18, the hole 17 having a small inner diameter may be formed first, and then the hole 16 having a large inner diameter may be formed so as to enclose it. Further, the double hole 18 can be formed so as to penetrate a plurality of layers in the depth direction.

FIG. 4 shows a laser processing apparatus according to the second embodiment. This laser processing apparatus is configured using acousto-optic deflection elements (AODs) 31 and 32 instead of the galvanometer mirrors 10 and 13 of the laser processing apparatus shown in FIG. The controller 33 can switch the beam diameter of the laser light emitted from the light source 1 to four stages by changing the deflection angle by switching the frequency of the RF signal sig ₃ transmitted to the first AOD 31 to four stages. .

The controller 33, by actuating the second AOD32 synchronism with the first AOD31, is emitted along a laser beam which is switched the beam diameter to one exit optical axis S _OUT. Note that the synchronization control of the first AOD 31 and the second AOD 32 is performed by the controller 33 sending the RF signal sig ₃ to the first AOD 31 and at the same time an RF signal having a frequency equal to the frequency of the RF signal sig _3. This is realized by sending sig ₄ to the second AOD 32.

  Also in this laser processing apparatus, the beam diameter of the laser beam can be switched in four stages. Further, the AODs 31 and 32 do not have a mechanical drive part. The time required for the AODs 31 and 32 to change the deflection angle does not depend on the magnitude of the angle representing the amount of change. Therefore, compared to the case of using a mechanically driven deflector such as a galvanometer mirror, the time required for the switching can be made constant even when the beam diameter switching order is arbitrarily set.

  FIG. 5 shows a laser processing apparatus according to the third embodiment. This laser processing apparatus is configured by using polygon mirrors 41 and 42 in place of the galvanometer mirrors 10 and 13 of the laser processing apparatus shown in FIG.

  Also in this laser processing apparatus, the beam diameter of the laser beam can be switched in four stages. In addition, the controller 43 causes the pair of polygon mirrors 41 and 42 to rotate synchronously (for example, constant-speed rotational movement), thereby periodically changing the beam diameter of the laser light emitted from the light source 1 at high speed. be able to.

  When, for example, eight polygon mirrors are used as the polygon mirrors 41 and 42, the range in which the deflection angle can be changed is about 90 degrees. This value is much larger than other deflectors such as galvanometer mirrors. Therefore, the optical path of the laser beam can be distributed in a wider space than when a galvanometer mirror or the like is used as a deflector. Therefore, a larger number of masks can be arranged, so that the number of beam diameter switching can be increased.

  In the laser processing apparatuses according to the first to third embodiments described above, the deflection angle of the laser beam in the front stage deflector (galvano mirror 10, AOD 31, or polygon mirror 41) and the rear stage deflector (galvano mirror 13, Both are operated in synchronism so that the deflection angles of the laser light in the AOD 32 or the polygon mirror 42) are equal. A steady deviation may be provided between the deflection angle of the laser beam in the former stage deflector and the deflection angle of the laser beam in the latter stage deflector.

The focal position of the second parabolic mirror 12 may be redesigned so that one processing point on the workpiece substrate W ₁ surface. That is, the subsequent stage deflector is omitted, and the substrate to be processed W ₁ is held at the focal position of the second parabolic mirror 12. However, in this case, with the change of the deflection angle of the laser beam in front of the deflector, it will change the incident angle of the laser beam to a processing substrate W _1. Therefore, it is preferable to provide a swinging mechanism for swinging the workpiece substrate W ₁ so as to cancel the change of the incident angle of the laser beam to a processing substrate W _1. In this case, the swing mechanism is preferably operated so that the incident direction of the laser light to the substrate W to be processed is always perpendicular to the surface of the substrate W to be processed.

  FIG. 6 shows a laser processing apparatus according to the fourth embodiment. A light source 50 emits linearly polarized laser light. When a laser oscillator that does not emit linearly polarized light is used, linearly polarized light may be obtained using a polarizer.

The laser light emitted from the light source 50 is incident on the beam diameter switch 60 along one of the incident optical axis S _IN. Beam diameter switcher 60 switches the beam diameter of the incident laser beam along an incident optical axis S _IN, emits along the laser light beam diameter is switched to one of the exit optical axis S _OUT.

The beam diameter switching device 60 will be described. On the incident optical axis _{S IN,} a polarization beam splitter; and (PBS Polarized Beam Splitter) 61 and the quarter-wave plate 62 are disposed in this order. The PBS 61 and the quarter wavelength plate 62 constitute a separation optical system.

A position where the laser beam is incident traveling along the incident optical axis S _IN passes through the quarter wave plate 62, the galvanometer mirror 63 is arranged. The incident position of the laser beam on the reflecting surface of the galvanometer mirror 63 is the laser beam deflection point P ₁ in the galvanometer mirror 63. The parabolic mirror 64 is positioned to the deflection point P ₁ and the focal point.

  A plane mirror 65 is arranged so as to face the rotary parabolic mirror 64. The plane mirror 65 is disposed perpendicular to the rotational symmetry axis of the rotary parabolic mirror 64. A beam diameter adjusting unit 66 is provided between the rotating paraboloid mirror 64 and the plane mirror 65 facing each other.

Laser light (linearly polarized light) emitted from the light source 50 first enters the PBS 61. The light source 50 emits laser light linearly polarized in the first direction. The PBS 61 transmits laser light linearly polarized in the first direction. The laser beam that has passed through the PBS 61 passes through the quarter-wave plate 62 and enters the deflection point P ₁ of the galvanometer mirror 63.

The galvanometer mirror 63 deflects the laser light incident on the deflection point P ₁ in a direction along one optical axis selected from the _first to fourth optical axes S ₁ , S ₂ , S ₃ , and S _4. . The galvanometer mirror 63 changes the deflection angle of the laser beam incident on the deflection point P ₁ in accordance with the control signal sig ₇ given from the controller 67. Thus, it switched deflection direction of the laser beam incident on the deflection point P _1.

The paraboloid mirror 64 is configured so that laser beams incident along the _first to fourth optical axes S ₁ , S ₂ , S ₃ , and S ₄ are first to fourth parallel optical axes parallel to each other. Reflects in a direction along SP ₁ , SP ₂ , SP ₃ , and SP ₄ . The beam diameter adjusting unit 66 makes the beam diameters of the laser beams traveling on the first to fourth parallel optical axes SP ₁ , SP ₂ , SP ₃ , and SP ₄ different from each other. Each of the laser beams traveling on the first to fourth parallel optical axes SP ₁ , SP ₂ , SP ₃ , and SP ₄ is incident on the plane mirror 65. The plane mirror 65 is arranged perpendicular to the first to fourth parallel optical axes SP ₁ , SP ₂ , SP ₃ , and SP ₄ , and receives the laser light incident along the _i-th parallel optical axis SP _i . It is folded back so as to be incident on the rotary parabolic mirror 64 via the i-th parallel optical axis SP _i again. Here, i is an arbitrary natural number of 1 or more and 4 or less.

  FIG. 7 is a cross-sectional view of the beam diameter adjusting unit 66 and the reflecting mirror 65. FIG. 7 shows only the laser beam folded by the plane mirror 65 for convenience. The beam diameter adjusting unit 66 is configured by providing masks 66 a, 66 b, 66 c, and 66 d at the laser light incident positions on the reflecting surface of the plane mirror 65, respectively. The inner diameters of the pinholes formed in each mask are different from each other. Since the mask is carried on the plane mirror 65, a member for holding the mask becomes unnecessary. Accordingly, the configuration of the beam diameter adjusting unit 66 can be simplified correspondingly.

Returning to FIG. 6, the description will be continued. The laser beam turned back in the direction along the parallel optical axes SP _i of the i by the plane mirror 65 is incident on the parabolic mirror 64 rotates along parallel optical axes SP _i of the i. The laser light incident on the rotary parabolic mirror 64 along the i-th parallel optical axis SP _i is reflected there, and is reflected on the deflection point P ₁ of the galvano mirror 63 along the _i- th optical axis S _i. Incident. Galvanometer mirror 63, the laser beam incident on the deflection point P ₁ along the optical axis of the i, as the return laser beam is deflected in the direction along the incident optical axis S _IN. Here, i is an arbitrary natural number of 1 or more and 4 or less.

The galvanometer mirror 63, the return laser beam deflected in the direction along the incident optical axis S _IN is incident on the quarter-wave plate 62 again. That is, the laser light emitted from the light source 50 passes through the quarter-wave plate 62 a total of two times, going and returning. Therefore, the linear polarization direction of the return laser beam is a second direction orthogonal to the first direction. The PBS 61 reflects the laser light linearly polarized in the second direction in a direction along the outgoing optical axis S _OUT orthogonal to the incident optical axis S _IN .

The laser light traveling along the outgoing optical axis S _OUT enters the workpiece substrate W ₁ held on the XY table 5 via the galvano scanner 3 and the fθ lens 4.
According to this laser processing apparatus, the laser beams deflected in the directions along the first to fourth optical axes S ₁ , S ₂ , S ₃ , and S ₄ by the galvanometer mirror 63 are respectively in the inner diameter of the pinhole. Passes through different masks 66a, 66b, 66c, and 66d, the beam diameter of the laser light can be switched in four stages.

  In the first to third embodiments described above, the first deflector (the first galvano mirror 10, the first AOD 31, the first polygon) for switching the optical path of the laser light emitted from the light source 1 is used. 2 of a mirror 41) and a second deflector (second galvanometer mirror 13, second AOD 32, second polygon mirror 42) for matching the optical axes of the laser beams whose beam diameters have been changed. Two deflectors were used.

  On the other hand, in the fourth embodiment, since the plane mirror 65 is arranged perpendicular to the rotation target axis of the rotary parabolic mirror 64 at a position facing the rotary parabolic mirror 64, a galvano as a single deflector. The mirror 63 can serve both as a function of switching the optical path of the laser light and a function of matching the optical axis of the laser light whose beam diameter has been changed. Since only one deflector is required, control for synchronizing the two deflectors becomes unnecessary. Moreover, since only one rotary parabolic mirror 64 is used, the apparatus can be realized at a low cost.

FIG. 8 shows a laser processing apparatus according to the fifth embodiment. This laser processing apparatus is configured by using an AOD 71 in place of the galvanometer mirror 63 of the laser processing apparatus shown in FIG. The AOD 71 converts the laser light incident on the deflection point P ₁ along the incident optical axis S _{IN out} of the optical axes of the first to fourth optical axes S ₁ , S ₂ , S ₃ , and S _4. Is deflected in a direction along one optical axis selected based on the control signal sig ₈ given by

  Also in this laser processing apparatus, the beam diameter of the laser beam can be switched in four stages. In addition, since the AOD 71 that is electrically driven is used as the deflector, the time required to change the deflection angle of the laser beam is less than the angle that represents the amount of change compared to the case of using the mechanically driven deflector. Can be constant regardless of size.

FIG. 9 shows a laser processing apparatus according to the sixth embodiment. This laser processing apparatus is configured by using a polygon mirror 81 in place of the galvano mirror 63 of the laser processing apparatus shown in FIG. The polygon mirror 81 rotates according to the control signal sig ₉ given from the controller 82.

  Also in this laser processing apparatus, the beam diameter of the laser beam can be switched in four stages. Further, since the polygon mirror 81 is used as the deflector, the beam diameter of the laser light can be periodically changed at a high speed.

FIG. 10 shows a laser processing apparatus according to the seventh embodiment. The light source 1 emits laser light. The laser light emitted from the light source 1, along one of the incoming optical axis S _IN is incident on the beam diameter switch 90. Beam diameter switch 90 switches the optical characteristics of the laser beam incident along the incident optical axis S _IN, emits along the laser beam optical characteristics is switched to one of the exit optical axis S _OUT.

The beam diameter switch 90 will be described. A double-sided mirror 91 is disposed at a position where laser light traveling along the incident optical axis _SIN is incident. Incident position of the laser beam on the surface (first reflecting surface) 91a of the double-sided mirror 91, a deflection point P ₁ of the laser beam on the first reflective surface 91a.

The deflection point P ₁ to the position where the focal point, the first parabolic mirror 92 is arranged. A first concave mirror 93 is arranged so as to face the first rotary parabolic mirror 92. A second concave mirror 94 is disposed so as to face the first concave mirror 93. As the concave mirrors 93 and 94, for example, spherical mirrors can be used.

A beam diameter adjusting unit 96 is disposed between the first concave mirror 93 and the second concave mirror 94 facing each other. A second rotating paraboloid mirror 95 is disposed so as to face the second concave mirror 94. The focal point of the second parabolic mirror 95 is located on the back surface (second reflection surface) 91b of the double-sided mirror 91. The position of the focal point, a deflection point P ₂ of the laser beam on the second reflective surface 91b. The second reflecting surface 91a is parallel to the first reflecting surface 91b.

Sided mirror 91, the laser beam incident along the incident optical axis _{S IN,} the first reflecting surface 91a, the optical axis _S 1 of the first to _4, S 2, _{S 3,} and is selected from _{S 4} It reflects in the direction along one optical axis. The double-sided mirror 91 changes the deflection angle of the laser beam on the first reflecting surface 91a by swinging according to the control signal sig ₁₀ given from the controller 96. Thereby, the deflection direction of the laser light is switched.

The first rotary paraboloid mirror 92 receives laser beams incident along the _first to fourth optical axes S ₁ , S ₂ , S ₃ , and S ₄ , respectively, in parallel with each other. Reflected in the direction along the parallel optical axes SP ₁ , SP ₂ , SP ₃ , and SP ₄ . The first concave mirror 93 transmits laser beams incident along the first to fourth parallel optical axes SP ₁ , SP ₂ , SP ₃ , and SP ₄ , respectively, to the _{11th to} 14th optical axes S ₁₁ , S ₁₁ . ₁₂ , S ₁₃ , and S ₁₄ are reflected along the direction. The beam diameter adjusting unit 96 makes the beam diameters of the laser beams traveling on the _{11th to} 14th optical axes S ₁₁ , S ₁₂ , S ₁₃ , or S ₁₄ different from each other.

FIG. 11 shows the beam diameter adjusting unit 96. Beam diameter adjusting unit 96, the optical axis _S 11 of the eleventh to _14, S _{12, S 13,} and on _{S 14,} respectively mask 96a, 96b, 96c, and 96d are configured arranged. The inner diameters of the pinholes formed in each mask are different from each other. Accordingly, the beam diameters of the laser beams traveling on the _{11th to} 14th optical axes S ₁₁ , S ₁₂ , S ₁₃ , and S ₁₄ are adjusted to be different from each other.

Returning to FIG. Laser light traveling along the first to fourteenth optical axes S ₁₁ , S ₁₂ , S ₁₃ , and S ₁₄ is incident on the second concave mirror 94. The second concave mirror 94 receives laser beams incident along the _{11th to} 14th optical axes S ₁₁ , S ₁₂ , S ₁₃ , and S ₁₄ , respectively, and the _{11th to} 14th parallel optical axes SP parallel to each other. ₁₁ , SP ₁₂ , SP ₁₃ , and SP ₁₄ are reflected along the direction.

The second rotary paraboloid mirror 95 transmits laser beams incident along the _{11th to} 14th parallel optical axes SP ₁₁ , SP ₁₂ , SP ₁₃ , and SP ₁₄ , respectively, to the 21st to 24th optical axes. _{S 21, S 22, S 23} , and the direction along the _{S 24,} to be incident on the deflection point _{P 2} on the second reflecting surface 91b of the double-sided mirror 91.

  Since the second reflecting surface 91b is configured integrally with the first reflecting surface 91a, when the deflection angle of the laser light on the first reflecting surface 91a changes as the double-sided mirror 91 swings, The deflection angle of the laser beam on the second reflecting surface 91b also changes by the same angle as the angle representing the amount of change.

On the other hand, the optical system constituted by the first rotating parabolic mirror 92, the first concave mirror 93, the second concave mirror 94, and the second rotating parabolic mirror 95 is a laser on the first reflecting surface 91a. When the light deflection angle changes as the double-sided mirror 91 swings, the incident direction of the laser light incident on the second reflecting surface 91b is changed by the same angle as the angle representing the amount of change. . As a result, laser light incident on the second reflecting surface 91b from various directions is reflected in a direction along one outgoing optical axis S _OUT on the second reflecting surface 91b.

The first paraboloid mirror 92 and the second paraboloid mirror 95 are arranged such that the i-th optical axis S _i is an extension of the _{(i + 20)} -th optical axis S _{(i + 20).} Alternatively, it is preferable to face each other with the double-sided mirror 91 interposed therebetween so as to be arranged on a line parallel to the extension line. (Where i is an arbitrary natural number greater than or equal to 1 and less than or equal to 4). Accordingly, the outgoing optical axis S _OUT is arranged on an extension line of the incident optical axis S _IN or on a line parallel to the extension line. The

According to this laser processing apparatus, by controlling the attitude of the double-sided mirror 91 based on the switching signal sig ₁₀ sent from the controller 96, the optical path of the laser light emitted from the light source 1 is changed to the masks 96a, 96b, 96c. , And 96d can be switched to an optical path in which a desired one is arranged. Thereby, the beam diameter of a laser beam can be switched in four steps.

  In the first to third embodiments described above, the first deflector for switching the optical path of the laser beam emitted from the light source 1 and the optical axis of each laser beam whose beam diameter has been changed are matched. Two deflectors with a second deflector were used. On the other hand, in the seventh embodiment, the first reflecting surface 91a of the double-sided mirror 91 has the function as the first deflector, and the second deflector 91 has the same function as the second deflector. Therefore, only one deflector is required. This eliminates the need for synchronous control of the two deflectors.

  FIG. 12 shows a laser drawing apparatus according to the eighth embodiment. The light source 101 emits laser light. The light source unit 101 includes a helium / cadmium laser oscillator. The laser light emitted from the light source 101 is exposure laser light having a wavelength of 441.6 nm, for example. The light source 101 may be configured using a helium-neon laser oscillator, a semiconductor laser oscillator, or the like.

  On the optical path of the laser light emitted from the light source 101, a beam diameter switch 102 and an objective lens 103 are arranged in this order. The configuration of the beam diameter switch 102 is substantially the same as the configuration of the beam diameter switch 2 shown in FIG. However, the arrangement positions of the masks 15a, 15b, 15c, and 15d in the beam diameter switch 102 are adjusted so that all the distances along the optical path from the mask to the objective lens 103 are all equal. .

The beam diameter switcher 102 switches the beam diameter of the laser light emitted from the light source 101. Objective lens 103 focuses the laser beam which is switched with the beam diameter on the surface of the wafer W _2. On the surface of the wafer W _2, photoresist is applied. Wafer _{W 2} is held on the XY stage 104. While irradiating the wafer W ₂ with laser light, the holding position of the wafer W ₂ is moved in a two-dimensional direction by the XY stage 104. Thus, the photoresist film formed on the surface of the wafer W _2, can be drawn a desired pattern.

According to the laser drawing apparatus, without using a photomask, it draws a desired pattern on a photoresist film formed on the surface of the wafer W _2. By way of movement of the wafer W ₂ by the XY stage 104, it is possible to flexibly change the pattern to be drawn on the photoresist film, it is suitable for limited production of diversified products.

  FIG. 13A shows a pattern drawn by this laser drawing apparatus. The narrow line 110 is drawn with the beam diameter switcher 102 switching the beam diameter to a smaller value. On the other hand, the thick line 111 is drawn after the beam diameter is largely switched by the beam diameter switch 102.

  FIG. 13B shows a pattern drawn without changing the beam diameter as a comparative example. The drawing of the thick line portion 112 is realized by drawing a plurality of thin lines. Therefore, it takes extra time. If the beam spot is enlarged by replacing the objective lens with another lens, a thick line can be drawn without drawing a plurality of thin lines. However, even in that case, extra time is required for the replacement work of the objective lens.

  On the other hand, according to this laser drawing apparatus, the beam diameter of the laser beam is switched by the beam diameter switch 102, so that the line width of the drawing pattern can be quickly changed without the need to replace or move the objective lens 103. . Thereby, the drawing efficiency can be improved.

  For example, a light intensity adjusting element such as an acousto-optic modulator (AOM) is arranged on the optical path between the light source 101 and the beam diameter switch 102, and the intensity of the laser light emitted from the light source 101 is measured. May be adjusted by the light intensity adjusting element. Then, the fine adjustment of the line width of the drawing pattern is performed by adjusting the intensity of the laser beam by the light intensity adjusting element, and the beam diameter switch 102 performs the large adjustment of the line width of the drawing pattern. This can be done by switching the optical path.

  As mentioned above, although the Example was described, this invention is not limited to this. In the first to eighth embodiments, the beam diameter of the laser beam is changed. However, optical characteristics other than the beam diameter may be changed.

FIG. 14 (a) shows a main part of a light intensity distribution switcher capable of changing the intensity distribution in the beam cross section of the laser light. Parallel optical axes _SP 2 of the second to 4, SP _3, and SP ₄ respectively on expander 301, and 303 are arranged. The expander expands the beam diameter of the laser beam incident on itself, and emits the laser beam with the beam diameter expanded into a parallel beam. The expansion ratios of the beam diameters in the expanders 301 to 303 are different from each other. Specifically, the expansion ratio of the beam diameter increases in the order of the expanders 301, 302, and 303. A mask 304 is disposed on the outgoing optical axis _SOUT .

  FIG. 14B shows the intensity distribution in the beam cross section of the laser light that has passed through the mask 304. The horizontal axis indicates the radial position in the beam cross section, and the vertical axis indicates the intensity of the laser beam. In the figure, d represents the inner diameter of the pinhole formed in the mask 304.

Symbol A indicates the intensity distribution in the beam cross section of the laser beam passing through the first parallel optical axes SP _1. Laser light is incident on the mask 301 without passing through the expander. The intensity distribution in the beam cross section of the laser light when emitted from the light source has a substantially Gaussian distribution. In the mask 304, even after the beam diameter is limited to d, the intensity of the laser light is biased toward the center of the beam.

Symbol B shows the intensity distribution in the beam cross section of the laser beam passing through the second parallel optical axes SP _2. Laser light passes through the expander 301 and enters the mask 304. When the beam diameter is expanded by the expander 301, the intensity distribution in the region where the beam diameter is within d approaches more uniformly than the intensity distribution A. Therefore, a laser beam having a more uniform intensity distribution in the beam cross section than the laser beam passing through the _first parallel optical axis SP1 can be obtained.

Symbol C shows the intensity distribution in the beam cross section of the third laser beam passed through the parallel optical axes SP _3. Laser light passes through the expander 302 and enters the mask 304. The expansion ratio of the beam diameter in the expander 302 is larger than the expansion ratio of the beam diameter in the expander 301. Accordingly, a laser beam having a more uniform intensity distribution in the beam cross section than the laser beam passing through the _second parallel optical axis SP2 can be obtained.

Reference numeral D denotes the intensity distribution in the beam cross section of the fourth laser beam passed through the parallel optical axes SP _4. Laser light passes through the expander 303 and enters the mask 304. The expansion ratio of the beam diameter in the expander 303 is larger than the expansion ratio of the beam diameter in the expander 302. Therefore, a laser beam having a more uniform intensity distribution in the beam cross section than the laser beam passing through the _third parallel optical axis SP3 can be obtained.

  As described above, according to the light intensity distribution switching device shown in FIG. 14A, the intensity distribution in the beam cross section of the laser light emitted from the light source is converted into the intensity distributions A, B, C, and D. You can switch to either.

In addition, for example, if a light intensity adjusting element is disposed on each of the first to fourth parallel optical axes SP ₁ , SP ₂ , SP ₃ , and SP ₄ , the intensity of the laser light can be switched in four stages. A light intensity switch is realized. For example, an attenuator can be used as the light intensity adjusting element. The intensity attenuation rate of the laser light in each light intensity adjusting element is different from each other. Note that the light intensity adjusting element may not be disposed on one of the first to fourth parallel optical axes SP ₁ , SP ₂ , SP ₃ , and SP ₄ .

For example, a ½ wavelength plate may be disposed on each of the first to fourth parallel optical axes SP ₁ , SP ₂ , SP ₃ , and SP ₄ . Laser light that has been linearly polarized in advance is incident on one of the half-wave plates via the incident optical axis _SIN . By changing the directions of the polarization axes of the half-wave plates, a linear polarization direction switch capable of changing the linear polarization direction of the laser light is realized.

Further, for example, without placing an optical element in the first upper parallel optical axes SP _1, the second to fourth parallel optical axes _SP 2, SP _3, and on the SP _4, respectively Deporaraiza (depolarizer), circle A polarizer and an elliptical polarizer may be disposed. The depolarizer converts linearly polarized light incident on itself into random polarized light. Laser light that has been linearly polarized in advance is incident along the incident optical axis _SIN . As a result, a polarization state switch that can switch the polarization state of the laser light to any of linearly polarized light, random polarized light, circularly polarized light, and elliptically polarized light is realized.

FIG. 15 shows a reflecting portion that can be used in place of a rotating parabolic mirror. The reflection unit is configured by first to fourth micromirrors M ₁ , M ₂ , M ₃ , and M ₄ . The i-th micromirror M _i reflects the laser beam incident along the _i- th optical axis S _i in a direction along the i-th parallel optical axis SPi. (Here, i is an arbitrary natural number of 1 or more and 4 or less.) As each micromirror, for example, a plane mirror, a convex mirror, or a concave mirror can be used. If this reflection part is used, it is not necessary to use an expensive paraboloid of revolution.

  Further, the number of switching of the optical characteristics of the laser light is not particularly limited to four stages. According to the apparatus according to the first to eighth embodiments, the optical characteristics of the laser beam can be switched in three or more stages in principle. The design may be changed so that the optical characteristics of the laser beam are switched to only two stages. Further, the laser light emitted from the light source may be pulsed laser light or CW laser light (continuous wave).

In the beam diameter switching device according to the first to eighth embodiments, the laser beam incident along one incident optical axis S _IN is emitted until it is emitted along one output optical axis S _OUT. It is also possible to switch the spatial position of the optical path that passes through in steps. This is realized by preventing the laser light from being emitted from the light source during the period in which the deflector is operated to switch the optical path. When the laser beam emitted from the light source is a pulse laser beam, the deflector (galvano scanner, AOD, polygon mirror, or double-sided mirror) is operated within the period between the pulse and the next pulse. You should keep it.

In the beam diameter switching device according to the first to eighth embodiments, the laser beam incident along one incident optical axis S _IN is emitted until it is emitted along one output optical axis S _OUT. The spatial position of the optical path that passes through can be moved steplessly. This is realized by allowing laser light to continue to be emitted from the light source even during a period in which the deflector is operated to switch the optical path.

  Further, for example, instead of the beam diameter adjusting unit 15 shown in FIG. 1, the rotational parabolic mirrors 11 and 12 are opposed to each other so as to intersect the rotational parabolic mirrors 11 and 12. By arranging a light transmitting member that is arranged and configured so that the light transmittance of the laser light continuously changes in a direction perpendicular to the rotational symmetry axis, the intensity of the laser light can be adjusted steplessly. It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

It is the schematic of the laser processing apparatus by an Example. It is the schematic of the beam diameter adjustment part by an Example. It is sectional drawing of a to-be-processed substrate. It is the schematic of the laser processing apparatus by another Example. It is the schematic of the laser processing apparatus by other Example. It is the schematic of the laser processing apparatus by other Example. It is the schematic of the beam diameter adjustment part by other Example. It is the schematic of the laser processing apparatus by other Example. It is the schematic of the laser processing apparatus by other Example. It is the schematic of the laser processing apparatus by other Example. It is the schematic of the beam diameter adjustment part by other Example. It is the schematic of the laser drawing apparatus by an Example. (a) is a diagram which shows the pattern drawn by the laser drawing apparatus by an Example, (b) is a diagram which shows the pattern drawn without changing the beam diameter of a laser beam. (a) is the schematic of the light intensity distribution switch by an Example, (b) is a graph showing intensity distribution in the beam cross section of a laser beam. It is the schematic of the reflection part which can be used instead of a parabolic mirror.

Explanation of symbols

2 Beam diameter switcher (optical device)
5 XY stage (holding means)
10 First galvanometer mirror (first deflector)
11 First rotating parabolic mirror 12 Second rotating parabolic mirror 13 Second galvanometer mirror (second deflector)
15 Beam diameter adjusting part (optical characteristic adjusting means)
53 Galvano mirror (polarizer)
54 Rotating parabolic mirror 55 Plane mirror 91 Double-sided mirror
91a Surface of a double-sided mirror (first reflective surface)
91b Back side of double-sided mirror (second reflecting surface)
92 First rotating parabolic mirror 93 First concave mirror 94 Second concave mirror 95 Second rotating parabolic mirror 104 XY stage (holding means)
W ₁ substrate to be processed (object to be irradiated)
W ₂ wafer (object to be irradiated)

Claims (20)

A first deflector for deflecting laser light incident on a first deflection point along one incident optical axis at the first deflection point, and deflecting the laser light according to a control signal given from the outside A first deflector for changing the angle;
An optical system for causing the laser beam deflected by the first deflector to be incident on a common second deflection point via different optical paths depending on the deflection direction;
A second deflector for deflecting the laser beam incident on the second deflection point by the optical system at the second deflection point, the deflected laser beam traveling on a common outgoing optical axis; A second deflector that changes a deflection angle of the laser beam in accordance with a control signal given from the outside so as to propagate ;
Laser light disposed on the optical path between the first deflection point and the second deflection point through which the laser beam deflected by the first deflector passes, and deflected by the first deflector An optical apparatus comprising: an optical characteristic adjusting unit that varies the optical characteristic of each of the optical paths depending on the optical path through which the laser beam passes . When the first deflector changes the deflection angle of the laser beam, the optical system causes the incident of the laser beam to be incident on the second deflection point by the same angle as the angle representing the amount of change. Configured to change direction,
When the second deflector changes the deflection angle of the laser beam, the laser beam is incident on the second deflection point by the same angle as the angle representing the change amount. The optical apparatus according to claim 1, wherein the laser beam incident on the second deflection point is deflected in a direction along one outgoing optical axis by changing the deflection angle.   The second deflector has the first deflection so that the deflection angle of the laser beam deflected by the second deflector is equal to the deflection angle of the laser beam deflected by the first deflector. The optical apparatus according to claim 2, wherein the optical apparatus operates in synchronism with the instrument. The optical system is
A first parabolic mirror focusing on the first deflection point;
A second rotational parabola that faces the first paraboloid mirror so as to have a rotational symmetry axis that is focused on the second deflection point and coincides with the rotational symmetry axis of the first paraboloid mirror. The optical apparatus according to claim 1, comprising an object mirror.   The optical device according to any one of claims 1 to 4, wherein both the first deflector and the second deflector are made of a swinging reflecting mirror, an acoustooptic deflecting element, or a polygon mirror. The optical characteristic adjusting unit according to any one of claims 1 to 5, wherein at least one of a size of a beam section of the laser light, an intensity distribution in the beam section, and a polarization state is made different for each optical path. Optical device. A first deflector for deflecting laser light incident on a first deflection point along one incident optical axis at the first deflection point, and deflecting the laser light in accordance with a control signal given from the outside A first deflector for changing the angle;
An optical system for causing the laser beam deflected by the first deflector to enter a common second deflection point via different optical paths depending on the deflection direction;
A second deflector for deflecting the laser beam incident on the second deflection point by the optical system at the second deflection point, the deflected laser beam traveling on a common outgoing optical axis; A second deflector that changes the deflection angle of the laser beam in accordance with a control signal given from the outside so as to propagate,
The optical system is
A first paraboloid mirror that focuses on the first deflection point;
A second rotational parabola that faces the first parabolic mirror so as to have a rotational symmetry axis that is focused on the second deflection point and coincides with the rotational symmetry axis of the first parabolic mirror. With a mirror
Including optical device. The incident laser beam incident on the deflection point along one incident optical axis is deflected in a deflection direction determined according to a control signal given from the outside, and when the incident laser beam is deflected, Is a deflector that deflects laser light incident on the deflection point in the opposite direction as return laser light in a direction along the incident optical axis;
An optical system for causing the incident laser beam deflected by the deflector to enter the deflection point in a direction opposite to the deflection direction when deflected by the deflector after passing through different optical paths according to the deflection direction; An optical device comprising: an optical path including the incident optical axis, and separating means for separating and extracting the return laser light from a common optical path through which both the incident laser light and the return laser light pass. The optical system is
A rotating parabolic mirror focusing on the deflection point;
The optical apparatus according to claim 8, further comprising: a plane mirror facing the rotary parabolic mirror and disposed perpendicular to the rotational symmetry axis of the rotary parabolic mirror.   The optical device according to claim 8 or 9, wherein the deflector includes a swinging reflecting mirror, an acoustooptic deflecting element, or a polygon mirror.   An optical device disposed on the optical path through which the incident laser light deflected by the deflector passes, and having different optical characteristics of the incident laser light deflected by the deflector depending on the optical path through which the incident laser light passes. The optical apparatus according to claim 8, further comprising a characteristic adjusting unit.   The optical apparatus according to claim 11, wherein the optical characteristic adjusting unit changes at least one of a size of a beam section of the incident laser light, an intensity distribution in the beam section, and a polarization state for each optical path. A multi-reflecting surface body having a first reflecting surface and a second reflecting surface for deflecting both incident laser beams, wherein the deflection angle of the laser light incident on the first reflecting surface is the same as that of the multi-reflecting surface body. A multi-reflecting surface body configured to change the deflection angle of the laser light incident on the second reflecting surface by the same angle as the angle representing the amount of change when changing with movement; and
Incident on the first reflecting surface along one incident optical axis, and the laser beam deflected on the first reflecting surface is incident on the second reflecting surface through different optical paths depending on the deflection direction. When the deflection angle of the laser beam on the first reflecting surface changes, the laser beam incident on the second reflecting surface by the same angle as the angle representing the amount of change is changed. And an optical system configured to change the incident direction.   The optical system makes the incident of the laser light incident on the second reflecting surface so that the deflection angle of the laser light on the second reflecting surface becomes equal to the deflection angle of the laser light on the first reflecting surface. The optical apparatus according to claim 13, wherein the direction is changed.   The optical device according to claim 13 or 14, wherein the multi-reflecting surface body includes a double-sided mirror having one reflecting surface as the first reflecting surface and the other reflecting surface as the second reflecting surface. The optical system is
A first paraboloid mirror that focuses on a deflection point of the laser beam on the first reflecting surface;
A first concave mirror facing the first parabolic mirror;
A second concave mirror facing the first concave mirror;
16. The optical device according to claim 13, further comprising: a second paraboloid mirror that faces the second concave mirror and focuses on a deflection point of the laser light on the second reflecting surface. apparatus.   The optical characteristic of the laser beam which is arranged on the optical path through which the laser beam deflected by the first reflecting surface passes and which is deflected by the first reflecting surface is made different for each optical path through which the laser beam passes. The optical device according to claim 13, further comprising an optical property adjusting unit.   The optical apparatus according to claim 17, wherein the optical characteristic adjusting unit changes at least one of a size of a beam section of the laser light, an intensity distribution in the beam section, and a polarization state for each optical path. A light source that emits laser light;
An optical device according to any one of claims 1 to 18,
A laser irradiation apparatus comprising: holding means for holding an object to be irradiated at a position where the laser light incident through the optical device is incident after being emitted from the light source.   The laser irradiation apparatus according to claim 19, wherein the holding unit moves the irradiation position of the laser light on the surface of the irradiated object on the surface of the irradiated object.

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