Optical processing apparatus

Abstract

To provide an optical processing apparatus capable of appropriately forming a structure on an object.MEANS: An optical processing apparatus includes: a split optical system configured to split a first light beam, which enters thereto, into a second light beam including a plurality of light beams; a magnification varying optical system that is disposed on at least one of an optical path of the first light beam entering the split optical system and an optical path of the plurality of light beams included in the second light beam emitted from the split optical system; and a condensing optical system configured to condense the second light beam, where an object is processed by the second light beam from the condensing optical system.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an optical processing apparatus. [Background technology]

[0002] As an example of a processing device capable of processing an object, Patent Document 1 describes a processing device that forms a structure by irradiating a laser beam onto the surface of an object. This type of processing device is required to appropriately form a structure on the object (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Pat. No. 4,994,639 Summary of the Invention

[0004] According to a first aspect, an optical processing apparatus includes a splitting optical system that splits an incident first light beam into a second light beam including a plurality of light beams, a variable magnification optical system that is arranged at least one of an optical path of the first light beam incident on the splitting optical system and an optical path of the plurality of light beams included in the second light beam that emerges from the splitting optical system, and a focusing optical system that focuses the second light beam, and processes an object with the second light beam from the focusing optical system. According to a second aspect, the optical processing apparatus is the optical processing apparatus of the first aspect, further comprising a reflecting device arranged on the optical path of the second light beam between the splitting optical system and the focusing optical system, and having a movable reflecting surface that reflects the multiple light beams contained in the second light beam. According to a third aspect, in the optical processing apparatus of the first aspect, the multiple light beams included in the second light beam are three or more light beams, and the focusing optical system focuses each of the three or more light beams from the splitting optical system. [Brief description of the drawings]

[0005] [Figure 1]1 is a diagram illustrating a schematic configuration of an optical processing apparatus according to a first embodiment. [Diagram 2] FIG. 4 is a diagram showing an example of a light beam split by a splitting optical system. [Diagram 3] 4A and 4B are diagrams showing a light beam entering the second variable magnification optical system and a light beam exiting from the second variable magnification optical system. [Figure 4] FIG. 4 is a conceptual diagram showing a second light flux being focused on a focusing surface by a focusing optical system. [Diagram 5] FIG. 2 is a perspective view showing an example of a riblet structure formed on an object using the optical processing apparatus of the first embodiment. [Figure 6] FIG. 13 is a diagram showing another example of a split optical system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0006] In this specification, the term "variable magnification optical system" refers to an optical system in which at least one of the lateral magnification and angular magnification of the optical system changes due to the movement of the optical members that make up the optical system. Therefore, the variable magnification optical system also includes zoom lenses and varifocal lenses whose focal length changes due to the movement of the optical members, and optical systems whose angular magnification changes due to the movement of the optical members. The optical system whose angular magnification changes may change its angular magnification while maintaining the afocal system.

[0007] (Optical processing device of the first embodiment) FIG. 1 is a diagram showing a schematic configuration of an optical processing device 1 according to a first embodiment. The X, Y, and Z directions shown by arrows in FIG. 1 and each of the figures described later are orthogonal to each other, and the X, Y, and Z directions indicate the same direction in each of the figures. The XZ direction shown by arrows in FIG. 1 is a direction intermediate between the above-mentioned X and Z directions, that is, it is orthogonal to the Y direction and indicates a direction 45° away from each of the X and Z directions. Hereinafter, the directions indicated by the arrows are called the +X direction, the +Y direction, the +Z direction, and the +XZ direction, respectively. The position in the X direction is called the X position, the position in the Y direction is called the Y position, and the position in the Z direction is called the Z position.

[0008] The optical processing device 1 of the first embodiment is a device including a first variable magnification optical system 11, a splitting optical system 14, a second variable magnification optical system 19, a first reflecting member 24, a light collecting optical system 27, and a reflecting device 22. The optical processing device 1 irradiates light supplied from a light source device 10 onto a surface (work surface WS) of an object W, which is a workpiece.

[0009] A light source device 10 such as a laser emits a first light beam L1 having a diameter D0, i.e., an opening angle (divergence angle or convergence angle) of approximately 0. Here, the diameter of the light beam is, for example, a diameter of a light beam having a cross-sectional intensity distribution of a Gaussian distribution type, the diameter of the light beam being 1 / e of the peak intensity. 2 The supplied first light flux L1 having a diameter D0 travels in the -Z direction and is introduced into the first variable magnification optical system 11.

[0010] First variable magnification optical system 11 is, for example, an afocal variable magnification optical system including first barrel 12 and four lenses 13a to 13d. First barrel 12 moves front lens group 13a, 13b and rear lens group 13c, 13d in the Z direction. This changes the overall angular magnification of first variable magnification optical system 11.

[0011] When the first variable magnification optical system 11 is an afocal system, the first light beam L1, which is a substantially parallel light beam incident on the first variable magnification optical system 11, has its diameter enlarged or reduced by the first variable magnification optical system 11, and emerges from the first variable magnification optical system 11 with a diameter D1. Then, by changing the Z positions of the front group lenses 13a, 13b and the rear group lenses 13c, 13d of the first variable magnification optical system 11, the diameter D1 of the first light beam L1 changes.

[0012] The first light beam L1 having a diameter D1 emitted from the first variable magnification optical system 11 is incident on the splitting optical system 14. Therefore, it can be said that the first variable magnification optical system 11 is disposed on the optical path of the first light beam L1 that is incident on the splitting optical system 14.

[0013] FIG. 2 is a diagram showing an example of a light beam split by the splitting optical system 14. The splitting optical system 14 is, for example, a diffractive optical element 16, which is, for example, a phase type diffraction grating that is a one-dimensional light-transmitting diffraction grating, formed on a light-transmitting substrate 15. The diffractive optical element 16 is, for example, a grating extending in the Y direction that is periodically arranged in the X direction. Note that the concave-convex pattern (phase pattern) provided on the diffractive optical element 16 is not limited to a one-dimensional pattern. For example, it may be a phase type diffractive optical element having a two-dimensional concave-convex pattern (phase pattern) as disclosed in U.S. Pat. No. 5,580,300. Also, the diffractive optical element 16 may be an amplitude type diffractive optical element.

[0014] The first light beam L1 traveling in the +Z direction is diffracted by the diffractive optical element 16 and split in the X direction. Of these, the zeroth-order diffracted light L22, which is a straight light and is shown by a solid line, travels in the +Z direction. The +1st-order diffracted light L23, shown by a dashed line, travels in a direction away from the +Z direction in the +X direction by an angle φ2. And the -1st-order diffracted light L21, shown by a dotted line, travels in a direction away from the +Z direction in the -X direction by an angle φ1.

[0015] In addition to these, the diffractive optical element 16 may generate ±2nd order or higher diffracted light. Hereinafter, the 0th order diffracted light L22, the +1st order diffracted light L23, the -1st order diffracted light L21, and the ±2nd order or higher diffracted light are collectively or individually referred to as the second light beam L2. In addition, the diffracted lights (L22a, L23a, L21a, etc.) obtained after passing through the second variable magnification optical system 19 and the diffracted lights (L22b, L23b, L21b, etc.) obtained after passing through the focusing optical system 27 are collectively or individually referred to as the second light beam L2. That is, the second light beam L2 includes three or more light beams including, for example, the 0th order diffracted light L22, the +1st order diffracted light L23, and the -1st order diffracted light L21 in a cross section perpendicular to its traveling direction.

[0016] The angle φ1 between the traveling direction of the 0th-order diffracted light L22 and the traveling direction of the −1st-order diffracted light L21 is, for example, greater than 0° and less than 90°. Similarly, the angle φ2 between the traveling direction of the 0th-order diffracted light L22 and the traveling direction of the +1st-order diffracted light L23 is, for example, greater than 0° and less than 90°. Even if high-order diffracted light of ±2nd order or higher is included, among the three or more light beams (0th-order diffracted light L22, +1st-order diffracted light L23, −1st-order diffracted light L21, etc.) included in the second light beam L2 emitted from the splitting optical system 14, the angle formed by the axes along the respective traveling directions of two adjacent light beams is an acute angle.

[0017] The following description will be given with reference again to FIG. The second light beam L2 including the multiple light beams split by the splitting optical system 14 is incident on a combining optical system 17 consisting of a dichroic beam splitter, for example. The combining optical system 17 is an optical system that merges (combines) the second light beam L2 incident from the splitting optical system 14 with a third light beam L3, indicated by a two-dot chain line, incident from a position detection unit 18, and emits the combined light toward a second variable magnification optical system 19.

[0018] As an example, the second light beam L2 is light with a wavelength λ2, and the third light beam L3 is light with a wavelength λ3 different from the wavelength λ2, and the dichroic surface 17a of the combining optical system 17 transmits the second light beam L2 with the wavelength λ2 and reflects the third light beam L3 with the wavelength λ3. As described later, the third light beam L3 is reflected or scattered by the object W and becomes a fourth light beam L4, which enters the combining optical system 17 from the second variable magnification optical system 19 side. The combining optical system 17 guides the fourth light beam L4 incident from the second variable magnification optical system 19 side to the position detection unit 18. The position detection unit 18 will be described later.

[0019] The combining optical system 17 is not limited to the dichroic beam splitter described above, and may be composed of a flat glass plate having a dichroic mirror. Alternatively, when the second light beam L2 and the third light beam L3 are linearly polarized lights whose polarization planes are substantially orthogonal to each other, a polarizing beam splitter may be used.

[0020] The second light beam L2, which has exited the splitting optical system 14 and passed through the combining optical system 17, enters the second variable magnification optical system 19. Therefore, it can be said that the second variable magnification optical system 19 is disposed on the optical path of the second light beam L2 exiting from the splitting optical system 14. The third light beam L3 that is merged with the second light beam L2 by the combining optical system 17 also enters the second variable magnification optical system 19 together with the second light beam L2.

[0021] The second variable magnification optical system 19 is, for example, an afocal variable magnification optical system including a second lens barrel 20 and four lenses 21a to 21d. The second lens barrel 20 moves the front lens group 21a, 21b and the rear lens group 21c, 21d in the Z direction. This changes the angular magnification of the second variable magnification optical system 19 as a whole.

[0022] 3 is a diagram showing the second light beam entering the second variable magnification optical system 19 and the second light beam emerging from the second variable magnification optical system. As described above, of the second light beam L2 entering the second variable magnification optical system 19, the traveling direction of the 0th order diffracted light L22 is the +Z direction. The traveling direction of the -1st order diffracted light L21 is a direction away from the +Z direction in the -X direction by an angle φ1, and the traveling direction of the +1st order diffracted light L23 is a direction away from the +Z direction in the +X direction by an angle φ2. The diameters of the incident second light beams L21, L22, and L23 are all D1.

[0023] The second light beams L21, L22, and L23 incident on the second variable magnification optical system 19 become second light beams L21a, L22a, and L23a, respectively, and emerge from the second variable magnification optical system 19. The zeroth-order diffracted light L22a corresponding to the incident zeroth-order diffracted light L22 is emitted in the +Z direction. The -1st-order diffracted light L21a corresponding to the incident -1st-order diffracted light L21 is emitted in a direction away from the +Z direction in the -X direction by an angle φ3. The +1st-order diffracted light L23a corresponding to the incident +1st-order diffracted light L23 is emitted in a direction away from the +Z direction in the +X direction by an angle φ4. The diameters of the emitted second light beams L21a, L22a, and L23a are all D2.

[0024] The above-mentioned angles φ3, φ4, and diameter D2 change due to a change in the angular magnification of the second variable magnification optical system 19. Because the second variable magnification optical system 19 is an afocal system, even if the angular magnification of the second variable magnification optical system 19 changes, the opening angles of the emitted second light beams L21a, L22a, and L23a do not change.

[0025] 3, the ±2nd order or higher diffracted light emerging from the second variable magnification optical system 19 is similar to the +1st order diffracted light L23a and the −1st order diffracted light L21a described above, although the angles of the traveling directions from the +Z direction are different. Furthermore, the diameter, or further the opening angle or traveling direction of the third light beam L3 is also changed by the second variable magnification optical system 19.

[0026] In the following description, the second light beam L2 also includes ±2nd order or higher diffracted light. However, the ±2nd order or higher diffracted light differs from the +1st order diffracted light L23a and the −1st order diffracted light L21a only in the deviation angle of its traveling direction from the +Z direction, and other than that, the behavior of the ±2nd order or higher diffracted light is the same as that of the +1st order diffracted light L23a and the −1st order diffracted light L21a, so a description thereof will be omitted.

[0027] The following description will be given with reference again to FIG. The second light beams L21a, L22a, and L23a emitted from the second variable magnification optical system 19 and ±second-order or higher diffracted light (not shown) are incident on a reflecting surface 23 provided on the reflecting device 22. As an example, the reflecting surface 23 is a flat surface arranged along a plane parallel to the XZ direction and the Y direction. The second light beam L22a traveling in the +Z direction and incident on the reflecting surface 23 is reflected by the reflecting surface 23 in the +X direction.

[0028] The second light beam L21a, which travels in a direction away from the +Z direction by an angle φ3 in the -X direction and is incident on the reflecting surface 23, is reflected by the reflecting surface 23 in a direction away from the +X direction by an angle φ3 in the -Z direction. Also, the second light beam L23a, which travels in a direction away from the +Z direction by an angle φ4 in the +X direction and is incident on the reflecting surface 23, is reflected by the reflecting surface 23 in a direction away from the +X direction by an angle φ4 in the +Z direction.

[0029] The reflecting surface 23 is held by the driving member 24 via the reflecting device 22 so as to be swingable within a predetermined angle range, for example with the XZ direction as the center of rotation. As an example, a so-called galvanometer mirror may be used as the reflecting device 22, the reflecting surface 23, and the driving member 24. When the reflecting surface 23 swings within a predetermined angle range with the XZ direction as the center of rotation, the traveling direction of each of the second light beams L21a, L22a, and L23a reflected by the reflecting surface 23 changes (swings) between two directions separated from the above-mentioned direction by an angle twice the above-mentioned predetermined angle in the ±Y direction. Note that the configuration for actively changing the emission angle of the second light beam is not limited to the galvanometer mirror, and for example, a polygon mirror or an AOD (acousto-optical deflector) may be used.

[0030] The second light beams L21a, L22a, and L23a reflected by the reflecting surface 23 are incident on a second reflecting surface 26 provided on the second reflecting device 25. The second reflecting surface 26 is, for example, a flat surface arranged along a plane parallel to the XZ direction and the Y direction, and reflects the traveling directions of the second light beams L21a, L22a, and L23a that travel in a direction centered on the above-mentioned +X direction and are incident on the second reflecting surface 26, in each direction centered on the +Z direction. The second reflecting device 25 does not need to be held swingably, but may be fixedly held relative to the entire optical processing apparatus 1. The second reflecting device 25 may be held swingably.

[0031] The second light beams L21a, L22a, and L23a reflected by the second reflecting surface 26 are incident on the focusing optical system 27. The second light beams L21a, L22a, and L23a are converted into second light beams L21b, L22b, and L23b, which are convergent light beams, by the focusing optical system 27. Then, at the focusing surface CP, the second light beam L21b is focused at the focusing section S1, the second light beam L22b is focused at the focusing section S2, and the second light beam L23b is focused at the focusing section S3.

[0032] The light collecting optical system 27 includes, as an example, three lenses 27a to 27c, one of which, lens 27b, is held by a focal position changing member 28. The focal position (position of the light collecting plane CP) of the light collecting optical system 27 can be adjusted by moving lens 27b in the Z direction by the focal position changing member 28. Note that instead of or in addition to the configuration in which at least a part of the lenses constituting the light collecting optical system 27 is moved in the Z direction to change the focal position, a configuration in which an optical member (typically a lens) movable along the light traveling direction is provided in the optical path of the second light flux and / or the third light flux between the synthesis optical system 17 and the light collecting optical system 27 may be used.

[0033] Fig. 4 is a conceptual diagram showing the second light beams L21b-L23b focused on the focusing surface CP by the focusing optical system 27. For simplification, Fig. 4 shows the focusing optical system 27 as a single lens. Fig. 4 also shows the surface MP on which the reflecting surface 23 is disposed, but omits the illustration of the second reflecting surface 26. For this reason, Fig. 4 shows the second light beams L21a-L23a emitted from the reflecting surface 23 as traveling in a direction centered on the +Z direction. The diameters of the second light beams L21a-L23a are all D2, as described above.

[0034] As described above, the second light beams L21a-L23a incident on the focusing optical system 27 are converted into second light beams L21b-L23b, which are convergent light beams, by the refractive power of the focusing optical system 27, and are focused on the three focusing portions S1-S3 aligned in the X direction, respectively. The third light beam L3 is also focused by the focusing optical system 27 on the second focusing portion S10 on the focusing surface CP.

[0035] The aperture angle θ of the second light fluxes L21b to L23b is determined by the formula (1) using the focal length f of the focusing optical system 27. 2 × f × sin(θ) = D2 (1) The second light beams L21a to L23a all have the same diameter D2, and therefore the opening angles θ of the second light beams L21b to L23b are also the same.

[0036] A diameter D3 of the three light-collecting portions S1 to S3 on the light-collecting surface CP is expressed by formula (2) using the wavelength λ2 of the second light flux L2 and the divergence angle θ. D3 = 2×λ2 / {π×sin(θ)} ···(2)

[0037] By changing the angular magnification of the second variable magnification optical system 19, the diameter D2 of the second light beams L21a-L23a changes, and therefore the opening angle θ of the second light beams L21b-L23b can be changed. As a result, the diameter D3 of the three light collecting portions S1-S3 can be changed according to formula (2).

[0038] Incidentally, the diameter D2 of the second light beams L21a-L23a can be changed similarly by changing the angular magnification of the first variable magnification optical system 11. This is because, when the angular magnification of the first variable magnification optical system 11 is changed, the diameter D1 of the first light beam L1 emerging from the first variable magnification optical system 11 is changed, and the diameter D2 of the second light beams L21a-L23a emerging from the second variable magnification optical system 19 is proportional to the diameter D1 of the first light beam L1.

[0039] Therefore, by changing the angular magnification of the first variable magnification optical system 11, the opening angle θ of the second light fluxes L21b to L23b can be changed, and the diameter D3 of the three light collecting portions S1 to S3 can be changed.

[0040] As an example, the focusing optical system 27 is a so-called fθ lens system. The projection characteristic of the focusing optical system 27 is not limited to fθ. When the projection characteristic of the focusing optical system 27 is fθ, the distance from the optical axis AX of the focusing optical system 27 to the focusing portions S1 to S3 on the focusing surface CP is proportional to the deviation angle from the +Z direction of the traveling direction of each of the second light beams L21a to L23a emitted from the reflecting surface 23. Since the second light flux L22a travels in the +Z direction from the reflecting surface 23, the position in the X direction of the light-concentrating portion S2 of the second light flux L22b concentrated by the focusing optical system 27 coincides with the optical axis AX.

[0041] Since the second light beam L21a travels in a direction away from the reflecting surface 23 in the -X direction by an angle φ3 with respect to the +Z direction, the position of the light collecting section S1 in the X direction is a position away from the optical axis AX in the -X direction by a distance P1. Also, since the second light beam L23a travels in a direction away from the reflecting surface 23 in the +X direction by an angle φ4 with respect to the +Z direction, the position of the light collecting section S3 in the X direction is a position away from the optical axis AX in the +X direction by a distance P2. The distances P1 and P2 can also be said to be the intervals in the X direction between the light collecting sections S1 to S3, and therefore, hereinafter, the distances P1 and P2 will also be referred to as the interval P1 and the interval P2, respectively.

[0042] The distance P1 is a value obtained by multiplying the angle φ3 by the focal length of the focusing optical system 27, and the distance P2 is a value obtained by multiplying the angle φ4 by the focal length of the focusing optical system 27. As described above, the angles φ3 and φ4 can be changed by changing the angular magnification of the second variable magnification optical system 19. Therefore, by changing the angular magnification of the second variable magnification optical system 19, the intervals P1, P2 in the X direction between the multiple focusing sections S1 to S3 can be changed.

[0043] To summarize the above, the opening angle θ of the second light beams L21b-L23b can be changed by changing the angular magnification of the first variable magnification optical system 11, and the diameter D3 of the multiple light collecting portions S1-S3 can be changed. Also, the opening angle θ of the second light beams L21b-L23b can be changed by changing the angular magnification of the second variable magnification optical system 19, and the diameter D3 of the multiple light collecting portions S1-S3 can be changed, and the intervals P1, P2 in the X direction between the multiple light collecting portions S1-S3 can be changed.

[0044] In other words, the intervals P1, P2 in the X direction between the multiple light collecting parts S1 to S3 can be changed to desired values ​​by changing the angular magnification of the second variable magnification optical system 19. Accordingly, the opening angle θ of the second light beams L21b to L23b is also changed, but the opening angle θ of the second light beams L21b to L23b can be set to a desired value by changing the angular magnification of the first variable magnification optical system 11. Therefore, by changing the magnification of the first variable magnification optical system 11 and the second variable magnification optical system 19, the opening angle θ of the multiple second light beams L21b to L23b emitted from the light collecting optical system 27 and the intervals P1, P2 in the X direction between the multiple light collecting parts S1 to S3 collected on the light collecting surface CP can be changed independently.

[0045] As described above, when the reflecting surface 23 of the reflecting device 22 swings within a predetermined angle range with the XZ direction as the center of rotation, the traveling direction of the second light flux L2 reflected by the reflecting surface 23 swings in the ±Y direction by an angle twice the predetermined angle with the above-mentioned direction, which is roughly the +X direction, as the center. Therefore, when the reflecting surface 23 of the reflecting device 22 swings, the multiple light collecting sections S1 to S3 swing (move) in the Y direction on the light collecting surface CP.

[0046] In the optical processing apparatus 1 of the first embodiment, the respective focusing portions S1 to S3 of the multiple second light beams L2 that are focused on the focusing surface CP are aligned in the X direction. In other words, the splitting optical system 14 splits the first light beam L1 into multiple second light beams L2 so as to be focused on the multiple focusing portions S1 to S3 that are aligned in the X direction on the focusing surface CP.

[0047] It can also be said that the reflecting surface 23 of the reflecting device 22 oscillates along the Y direction intersecting with the X direction so that the light collecting portions S1 to S3 move on the light collecting surface CP. The X direction may also be referred to as the first direction, and the Y direction may also be referred to as the second direction.

[0048] A processing surface WS of an object W, which is a workpiece, is disposed on the light-collecting plane CP. The optical processing apparatus 1 of the first embodiment has a sample stage 29 that holds the object W and moves on a guide 30 in the X direction. With the object W and sample stage 29 positioned at a predetermined X position, the reflecting surface 23 of the reflecting device 22 is swung within a predetermined angle range with the XZ direction as the center of rotation, thereby allowing each of the multiple focusing sections S1 to S3 to move (scan) in the Y direction on the processed surface WS of the object W.

[0049] 5 is a perspective view showing an example of a riblet structure formed on a work surface WS of an object W using the optical processing apparatus 1 of the first embodiment. When forming the riblet structure, a plurality of light-collecting sections S1 to S3 arranged in the X direction on the light-collecting surface CP are scanned in the Y direction on the light-collecting surface CP with the work surface WS aligned to the light-collecting surface CP. This makes it possible to form a group of recesses SG on the work surface WS, each of which extends in the Y direction and includes, for example, three recesses RS that are periodically arranged in the X direction. The recesses RS may also be called grooves.

[0050] Then, by scanning the focusing parts S1-S3 on the focusing surface CP in the Y direction a number of times while sequentially moving the X positions of the object W and the sample stage 29, a riblet structure consisting of a number of recesses RS can be formed on the processing surface WS. Here, the riblet structure may be considered to be composed of a number of protrusions PS or uneven parts. The movement of the X positions of the object W and the sample stage 29 may be continuous movement in the X direction at a substantially constant speed.

[0051] Each recess RS may be formed by melting, evaporating or sublimating a part of the work surface WS of the object W, such as a metal, by irradiation with the second light beam L2, which is the processing light. Alternatively, a powder of metal or the like placed on the work surface WS of the object W, such as a metal, may be melted by irradiation with the second light beam L2, and solidified to form convex portions, thereby forming recesses between the convex portions. Alternatively, a coating film on the work surface WS of the object W may be melted, evaporating or sublimating by irradiation with the second light beam L2 to form recesses.

[0052] The number of the light collecting sections S1 to S3 arranged in the X direction on the light collecting surface CP is not limited to three as described above, but may be any number equal to or greater than two. In the optical processing device 1 of the first embodiment, a plurality of focusing sections S1 to S3 are formed aligned in the X direction on the focusing surface CP, and these plurality of focusing sections S1 to S3 are moved (scanned) collectively in the Y direction to process the processing surface WS of the object W, thereby improving the processing speed compared to the case where a single focusing section is scanned for processing.

[0053] In the optical processing apparatus 1 of the first embodiment, the diameter D3 (or the opening angle θ of the second light fluxes L21b-L23b toward the light collecting surface CP) of each of the multiple light collecting portions S arranged in the X direction on the light collecting surface CP and the intervals P1, P2 in the X direction can be changed, so that the width of each recess RS (or the width of the protrusion PS) to be processed on the work surface WS of the object W, the interval in the X direction between the multiple recesses RS (or the interval in the X direction between the multiple protrusions PS), and the ratio between the width of the recess RS and the protrusion PS can be freely changed. Therefore, multiple types of structures can be formed on the work surface WS depending on the application of the object W, etc.

[0054] As an example, the angle θ of the second light fluxes L21b-L23b toward the light-collecting surface CP can be changed to change the inclination of the slope of the recesses RS of the riblet structure (the inclination of the slope of the protrusions PS). When processing the recesses RS extending in the Y direction, the light-collecting portion S may be moved in the Y direction to perform processing, and then the position of the light-collecting portion S may be moved in the X direction, and then the light-collecting portion S may be moved in the Y direction to perform processing. In this case, the amount of movement of the light-collecting portion S in the X direction may be smaller than the diameter D3 of the light-collecting portion.

[0055] The third light beam L3, which is emitted from the position detection unit 18 and merged (combined) with the second light beam L2 by the combining optical system 17, passes through the second variable magnification optical system 19, the reflecting surface 23, the second reflecting surface 26, and the focusing optical system 27, and is focused at the second focusing unit S10 on the focusing surface CP, just like the second light beam L2. The third light beam L3 is then irradiated onto the work surface WS of the object W placed on the focusing surface CP. The third light beam L3 irradiated onto the work surface WS is reflected or scattered by the work surface WS, and at least a part of it becomes a fourth light beam L4, which travels along an optical path generally similar to that of the third light beam L3, in the opposite direction to that of the third light beam L3, and returns to the combining optical system 17.

[0056] The fourth light beam L4 is reflected by the dichroic surface 17a of the combining optical system 17, and is guided to the position detection unit , and is received by the position detection unit . The position detection unit 18 detects the position of the object W, for example, in the Z direction, based on the received fourth light beam L4. The position detection unit 18 may include, for example, an interferometer. As such a position detection unit, the three-dimensional shape measurement device disclosed in Japanese Patent No. 5231883 may be applied. Alternatively, the position detection unit 18 may detect the position of a portion of a predetermined shape on the work surface WS of the object W in the X direction or Y direction.

[0057] The first variable magnification optical system 11 and the second variable magnification optical system 19 are not limited to afocal systems, but may be a so-called zoom lens system whose focal length changes, or a varifocal system. In this case, as the magnification of the first variable magnification optical system 11 or the second variable magnification optical system 19 changes, not only the diameter of the light beam emitted from the first variable magnification optical system 11 or the second variable magnification optical system 19 but also the opening angle changes.

[0058] Furthermore, the number of lenses constituting the first variable magnification optical system 11, the second variable magnification optical system 19, and the condensing optical system 27 is not limited to the above-mentioned number, and each may have any number of lenses. Alternatively, at least one of the first variable magnification optical system 11, the second variable magnification optical system 19, and the condensing optical system 27 may be a reflective optical system or a catadioptric optical system including a reflective optical member such as a mirror or a prism. At least one of the first variable magnification optical system 11, the second variable magnification optical system 19, and the condensing optical system 27 may be a diffractive optical system.

[0059] In the above example, the combining optical system 17 is disposed between the splitting optical system 14 and the second variable magnification optical system 19, but it may be disposed inside the second variable magnification optical system 19 or between the second variable magnification optical system 19 and the reflecting device 22. When it is not necessary to move the third light flux L3 on the light collecting plane CP, the combining optical system may be disposed on the light collecting plane CP side of the reflecting device 22.

[0060] The optical processing device 1 does not necessarily have to have either the first variable magnification optical system 11 or the second variable magnification optical system 19. As described above, when the optical processing device 1 includes the second variable magnification optical system 19, the aperture angle θ of the second light beams L21b-L23b can be changed by varying the magnification of the second variable magnification optical system 19, and the intervals P1, P2 in the X direction between the multiple light collecting sections S1-S3 can be changed. When the optical processing device 1 includes the first variable magnification optical system 11, the aperture angle θ of the second light beams L21b-L23b can be changed by varying the magnification of the first variable magnification optical system 11.

[0061] The sample stage 29 may move the held object W in the X and Y directions. In this case, instead of swinging the reflecting device 22 and the reflecting surface 23, the sample stage 29 moves the object W relative to the light collecting parts S1 to S3, thereby moving (scanning) the relative positions of the light collecting parts S1 to S3 in the processed surface WS of the object W in the Y direction. Therefore, in this case, the optical processing apparatus 1 does not need to have the reflecting device 22 and the reflecting surface 23.

[0062] In the above description, the second reflecting device 25 and the second reflecting surface 26 are fixed to the entire optical processing apparatus 1, but the second reflecting device 25 and the second reflecting surface 26 may be swung within a predetermined angle range with the Y direction as the center of rotation. This allows the light collecting parts S1 to S3 to be moved (scanned) in the X direction on the light collecting surface CP.

[0063] In this case, the multiple light collecting sections S1 to S3 on the light collecting surface CP are formed side by side in the Y direction on the light collecting surface CP. Also, the light collecting sections S1 to S3 move (scan) in the X direction on the light collecting surface CP by the oscillation of the reflecting surface 23. Therefore, in this case, the optical processing apparatus 1 does not need to have a sample stage 29 that holds the object W and moves it in the X direction.

[0064] In the above description, the splitting optical system 14 splits the first light beam L1 into a plurality of second light beams L2 in the X direction, and the reflecting device 22 and the reflecting surface 23 swing within a predetermined angle range with the XZ direction as the center of rotation. However, the present invention is not limited to this, and the splitting optical system 14 may split the first light beam L1 into a plurality of second light beams L2 in the Y direction, and the reflecting device 22 and the reflecting surface 23 may swing within a predetermined angle range with the Y direction as the center of rotation.

[0065] The splitting optical system 14 does not necessarily have to split the first light beam L1 so that the multiple light collecting parts S1 to S3 are aligned in the X direction or Y direction on the light collecting surface CP. Instead, the first light beam L1 may be split into the second light beam L2 so that the X positions or Y positions of the multiple light collecting parts S1 to S3 on the light collecting surface CP are different from each other. The splitting optical system 14 may also split the first light beam L1 into two second light beams L2.

[0066] The optical processing apparatus 1 does not need to have the light source device 10, and may, for example, receive the first light beam L1 from a light source provided outside the optical processing apparatus 1 via a light guiding member such as an optical fiber.

[0067] The splitting optical system 14 is not limited to a configuration having the above-mentioned diffractive optical element 16, but may be any optical system that splits the first light beam L1 into multiple second light beams L2 whose directions of travel are separated from each other by a predetermined angle.

[0068] 6 shows a splitting optical system 14a including a reflecting member as another example of the splitting optical system 14. In the splitting optical system 14a, the first light beam L1 incident thereon is split by the polarizing beam splitter 41 into a P-polarized first light beam L11 that transmits through the reflecting surface 41a and an S-polarized first light beam L12 that is reflected by the reflecting surface 41a.

[0069] The first light beam L1 of P polarized light transmitted through the polarizing beam splitter 41 is converted into circularly polarized light by the quarter-wave plate 42 and reflected by the reflecting mirror 43. It then transmits again through the quarter-wave plate 42 and is converted into S polarized light, reflected by the reflecting surface 41a of the polarizing beam splitter 41, and emerges from the splitting optical system 14a as the second light beam L21.

[0070] The first light beam L2 of S polarized light reflected by the polarizing beam splitter 41 is converted into circularly polarized light by the quarter-wave plate 44 and reflected by the reflecting mirror 45. It then passes through the quarter-wave plate 44 again and is converted into P polarized light, passes through the polarizing beam splitter 41, and is emitted from the splitting optical system 14a as the second light beam L22.

[0071] At this time, by arranging the reflecting surfaces of the reflecting mirrors 43 and 45 so as to be slightly offset from a perpendicular direction, the traveling directions of the second light beams L21 and L22 are offset by, for example, an angle difference φ1. In the configuration shown in FIG. 6, the traveling direction of the second light beam L21 and the second light beam L22 is approximately the -X direction, but by arranging a folding mirror (not shown), the traveling direction of the second light beam L21 and the second light beam L22 may be converted to approximately the +Z direction while maintaining the above-mentioned angular difference φ1.

[0072] The light beams emitted from the splitting optical system 14a are two, the second light beam L21 and the second light beam L22, but by arranging a plurality of splitting optical systems 14a in series, the single first light beam L1 may be divided into more second light beams L2. When a plurality of splitting optical systems 14a are arranged in series, a quarter-wave plate may be arranged between them to convert the second light beams L21 and L22 emitted from one splitting optical system 14a into circularly polarized light.

[0073] (Effects of the optical processing device of the first embodiment) (1) The optical processing apparatus 1 of the first embodiment described above includes a splitting optical system 14 that splits the incident first light beam L1 into a second light beam L2 including a plurality of light beams (L21, L22, L23), a variable magnification optical system (11, 19) that is arranged at least on the optical path of the first light beam L1 incident on the splitting optical system 14 and on the optical path of the plurality of light beams included in the second light beam L2 emerging from the splitting optical system 14, and a focusing optical system 27 that focuses the second light beam L2, and processes an object W with the second light beam L2 from the focusing optical system 27. With this configuration, multiple light-converging areas S1 to S3 can be formed on the workpiece surface WS of the object W, and by varying the magnification of the variable magnification optical system (11, 19), the opening angle θ of each of the second light beams L21b to L23b that are focused on the light-converging areas S1 to S3 can be changed. Therefore, it is possible to realize an optical processing device 1 with high processing capacity that can simultaneously process multiple locations on the workpiece surface WS. Also, it is possible to realize an optical processing device 1 that can change (adjust) the diameter D3 of the light collecting parts S1 to S3, that is, the dimensions of the processing area of ​​the workpiece surface WS can be easily changed.

[0074] (2) The optical processing apparatus 1 may further include a reflecting device 22 that is arranged on the optical path of the second light beam L2 between the splitting optical system 14 and the focusing optical system 27 and has a movable reflecting surface 23 that reflects the multiple light beams contained in the second light beam L2. In this configuration, the plurality of light collecting parts S1 to S3 formed on the workpiece surface WS can be moved (scanned) on the workpiece surface WS by the oscillation of the reflecting surface 23. This makes it possible to realize an optical processing apparatus 1 with higher processing capacity.

[0075] (3) In the optical processing apparatus 1, the multiple light beams contained in the second light beam L2 can be three or more light beams (L21, L22, L23), and the focusing optical system 27 can be configured to focus each of the three or more light beams from the splitting optical system 14. This configuration makes it possible to simultaneously process three or more locations on the workpiece surface WS, thereby realizing an optical processing device 1 with even higher processing capacity.

[0076] The present invention is not limited to the above. Other aspects conceivable within the scope of the technical idea of ​​the present invention are also included in the scope of the present invention. This embodiment may combine all or part of the above aspects. [Explanation of symbols]

[0077] 1: light processing device, 10: light source device, 11: first variable magnification optical system, 14: splitting optical system, 17: combining optical system, L1: first light beam, L2: second light beam, L3: third light beam, 18: position detection unit, 22: reflecting device, 23: reflecting surface, 27: focusing optical system, CP: focusing surface, 29: sample stage, 30: guide, W: object, WS: processing surface

Claims

1. A splitting optical system that splits an incident first light beam into a second light beam including a plurality of light beams; A first magnification optical system disposed on the optical path of the first light beam incident on the splitting optical system; A second magnification optical system disposed on the optical paths of the plurality of light beams included in the second light beam emitted from the splitting optical system; A condensing optical system that condenses the second light beam; A reflecting device disposed on the optical path of the second light beam passing through the splitting optical system, the reflecting device including a swingable reflecting surface that reflects the plurality of light beams including the second light beam; comprising; The object is processed by the second light beam passing through the condensing optical system; A laser processing device.

2. The first magnification optical system includes a lens group movable in the optical axis direction, Magnification is performed by moving the lens group in the optical axis direction; The laser processing device according to claim 1.

3. The first magnification optical system changes the size of the light beam incident on the splitting optical system; The laser processing device according to claim 1 or claim 2.

4. The second magnification optical system includes a lens group movable in the optical axis direction, Magnification is performed by moving the lens group in the optical axis direction; The laser processing device according to any one of claims 1 to 3.

5. The second magnification optical system is an afocal optical system with a variable angular magnification; The laser processing device according to any one of claims 1 to 4.

6. One or more of the plurality of lenses disposed on the optical path of the second light beam emitted from the splitting optical system are moved in the optical axis direction to change the position of the condensing surface of the second light beam emitted from the condensing optical system in the optical axis direction; The laser processing device according to any one of claims 1 to 5.

7. The plurality of light beams included in the second light beam emitted from the splitting optical system form a plurality of condensing portions arranged in one direction on the object; The laser processing device according to any one of claims 1 to 6.

8. The reflecting device scans the plurality of condensing portions in a direction different from the one direction; The laser processing device according to claim 7.

9. A riblet structure having a plurality of convex portions or a plurality of concavo-convex portions is formed on the surface of the object by the second light beam passing through the condensing optical system; The laser processing device according to any one of claims 1 to 8.

10. Irradiating the surface of an object with a plurality of light beams from the laser processing device according to any one of claims 1 to 9; Scanning, using the reflection device, a plurality of condensing portions formed by the plurality of light beams on the surface of the object A light processing method including this.

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