Laser processing apparatus

Abstract

A laser processing apparatus is disclosed. Disclosed is the laser processing apparatus comprising: a laser light source for generating laser light; a spatial light modulator for forming a processing modulation pattern by modulating the laser light provided by the laser light source; a condensing optical system for condensing, onto an object to be processed, the laser light modulated by the spatial light modulator; a relay lens optical system positioned between the spatial light modulator and the condensing optical system; and a control unit for controlling the spatial light modulator such that the laser light is modulated according to the processing modulation pattern. The relay lens optical system transfers an image of the processing modulation pattern formed by the spatial light modulator to the incident side of the condensing optical system, and includes a first lens group, a second lens group and a field lens between the first lens group and the second lens group.

Description

Laser processing device

[0001] The present invention relates to a laser processing device including a relay lens optical system.

[0002] Laser processing refers to the process of manipulating the shape or physical properties of an object's surface by beaming laser light onto it. For this process, laser light emitted from a laser source is focused onto a specific area of ​​the object being processed.

[0003] Laser processing devices enable non-contact, high-precision processing regardless of the material of the object being processed. Processing is performed using a focused laser beam that forms a spot, ensuring the thermal stability of the object being processed and enabling ultra-precision processing without being limited by the size of the processing area.

[0004] The size of these laser processing devices can be determined by the optical system used for laser processing. Therefore, optical system design for miniaturization of laser processing devices is required.

[0005] A laser processing device including a relay lens optical system designed to enable size reduction is provided.

[0006] A laser processing device according to one type includes: a laser light source that generates laser light; a spatial light modulator that modulates laser light provided from the laser light source to form a processing modulation pattern; a focusing optical system that focuses the laser light modulated by the spatial light modulator onto a processing object; a relay lens optical system positioned between the spatial light modulator and the focusing optical system and arranged to transmit an image of the processing modulation pattern formed by the spatial light modulator to an entrance pupil of the focusing optical system, the relay lens optical system including a first lens group, a second lens group, and a field lens between the first lens group and the second lens group; and a control unit that controls the spatial light modulator to modulate the laser light with the processing modulation pattern.

[0007] Each of the first lens group and the second lens group may include two or more lenses.

[0008] Each of the first lens group and the second lens group includes a first lens having positive refractive power and a second lens having negative refractive power, and the field lens may be provided to have positive refractive power.

[0009] The above relay lens optical system can be arranged to form a 3f lens unit.

[0010] The above spatial light modulator can form the processing modulation pattern under the control of the control unit so that the laser light modulated with the processing modulation pattern is focused on a plurality of focusing points at different depths inside the processing target by the focusing optical system.

[0011] The laser light modulated with the above-mentioned processing modulation pattern may include a light component having a different refractive power with respect to the basic light component.

[0012] The above spatial light modulator may include a reflective spatial light modulator.

[0013] An optical member is further included, and when the direction of propagation of the laser light incident from the laser light source to the optical member is referred to as a first propagation direction, the optical member is provided to cause the laser light to be incident obliquely onto the spatial light modulator and to propagate the laser light modulated and reflected by the spatial light modulator in a direction parallel to the first propagation direction, and the internal reflection surface may be a prism structure parallel to the spatial light modulator.

[0014] The above-mentioned light-gathering optical system may include an objective lens that focuses the incident laser light onto a processing target.

[0015] The above-mentioned light-gathering optical system may further include a beam expander provided between the relay lens optical system and the objective lens to expand the beam width of the laser light.

[0016] A reflection mirror is further included between the relay lens optical system and the objective lens, and the beam expander can be placed between the relay lens optical system and the reflection mirror or between the reflection mirror and the objective lens.

[0017] It may further include a stage configured to be capable of two-dimensional plane movement; and a stage position control unit that controls two-dimensional plane movement of the stage.

[0018] A laser processing device according to one type may include: a laser source that generates laser light; a reflective spatial light modulator that modulates laser light provided from the laser source to form a processing modulation pattern; a focusing optical system that focuses the laser light modulated by the reflective spatial light modulator onto a processing object and includes an objective lens; a relay lens optical system positioned between the reflective spatial light modulator and the focusing optical system and arranged to transmit an image of the processing modulation pattern formed by the reflective spatial light modulator to an entrance pupil of the focusing optical system, the relay lens optical system including a first lens group, a second lens group, and a field lens between the first lens group and the second lens group; a stage configured to be capable of two-dimensional plane movement; a stage position control unit that controls two-dimensional plane movement of the stage; and a control unit that controls the spatial light modulator to modulate the laser light with the processing modulation pattern.

[0019] Each of the first lens group and the second lens group may include two or more lenses.

[0020] Each of the first lens group and the second lens group includes a first lens having positive refractive power and a second lens having negative refractive power, and the field lens may be provided to have positive refractive power.

[0021] The above relay lens optical system can be arranged to form a 3f lens unit.

[0022] The above spatial light modulator can form the processing modulation pattern under the control of the control unit so that the laser light modulated with the processing modulation pattern is focused on a plurality of focusing points at different depths inside the processing target by the focusing optical system.

[0023] The laser light modulated with the above-mentioned processing modulation pattern may include a light component having a different refractive power with respect to the basic light component.

[0024] The optical system may further include a reflection mirror between the relay lens optical system and the objective lens, and the light-gathering optical system may further include a beam expander provided between the relay lens optical system and the reflection mirror or between the reflection mirror and the objective lens to expand the beam width of the laser light.

[0025] It further includes an optical member, and the optical member is provided so that, when the direction of propagation of the laser light incident from the laser light source to the optical member is referred to as a first propagation direction, the laser light is obliquely incident to the spatial light modulator, and the laser light modulated and reflected by the spatial light modulator is propagated in a direction parallel to the first propagation direction, and the internal reflection surface may be a prism structure parallel to the spatial light modulator.

[0026] According to the laser processing device according to the embodiment, the relay lens optical system for transmitting light between the laser light source and the focusing optical system can be reduced in size, thereby realizing miniaturization of the device. In addition, the number of lenses in the relay lens optical system can also be reduced, thereby realizing a laser processing device including an optical system configured with a reduced length of the optical system and a smaller number of lenses.

[0027] Fig. 1 schematically shows a laser processing device according to an embodiment.

[0028] Figure 2 is a plan view schematically illustrating an exemplary configuration of the processing object of Figure 1.

[0029] Figure 3 shows an example in which laser light modulated with a processing modulation pattern set by a spatial light modulator is focused onto multiple focusing points inside a processing target by a focusing optical system.

[0030] Figure 4 is intended to explain the principle of cracks occurring inside the processing target of Figure 3.

[0031] Fig. 5 schematically shows an embodiment of the relay lens optical system of Fig. 1.

[0032] FIG. 6a is for explaining the optical path length reduction effect of the relay lens optical system according to the embodiment.

[0033] Figure 6b shows the optical path length of the relay lens optical system of the comparative example.

[0034] FIGS. 7 and 8 show other embodiments of optical system configurations that can be applied to the laser processing device of FIG. 1.

[0035] FIG. 9a and FIG. 9b schematically show the optical path in the entire lens optical system of a relay lens optical system and a laser processing device (100) including the same according to an embodiment.

[0036] Table 1 of Fig. 10 shows the design data of the relay lens optical system according to the embodiment of Fig. 9a and the material and refractive power of the lens.

[0037] FIG. 11a, FIG. 11b, and FIG. 11c respectively show the MTF performance, aberration (chromatic aberration, astigmatism, distortion), and ray aberration of the entire lens optical system of the relay lens optical system and the laser processing device including the same according to the embodiment formed with the design data of Table 1 shown in FIG. 10.

[0038] Figures 12a and 12b schematically show the optical path in the relay lens optical system of the comparative example and the entire lens optical system of the laser processing device including the same.

[0039] Table 2 of Fig. 13 shows the design data of the relay lens optical system of the comparative example of Fig. 12a and the material and refractive power of the lens.

[0040] Figures 14a, 14b, and 14c respectively show the MTF performance, aberration (chromatic aberration, astigmatism, distortion), and ray aberration of a relay lens optical system of a comparative example formed with the design data of Table 2 and the entire lens optical system including the same of a laser processing device.

[0041] Hereinafter, exemplary embodiments will be described in detail with reference to the attached drawings. In the drawings below, like reference numerals designate like components, and the sizes of each component in the drawings may be exaggerated for clarity and convenience. The embodiments described below are merely exemplary, and various modifications are possible from these embodiments.

[0042] Hereinafter, the terms "upper" or "upper" may include not only those directly above, below, left, or right in contact, but also those directly above, below, left, or right in non-contact. Singular expressions include plural expressions unless the context clearly indicates otherwise. Furthermore, when a part is said to "include" a component, this does not exclude other components, but rather includes other components, unless otherwise specifically stated.

[0043] The use of the term "above" and similar referential terms may refer to both the singular and the plural. Unless the steps of a method are explicitly stated in a specific order or to the contrary, the steps may be performed in any appropriate order, and the order stated is not necessarily limited to that order.

[0044] Additionally, terms such as “part”, “module”, etc. described in the specification mean a unit that processes at least one function or operation, which may be implemented as hardware or software, or a combination of hardware and software.

[0045] The lines connecting or disconnecting between components depicted in the drawings are merely representative of functional connections and / or physical or circuit connections, and may be replaced or represented as various additional functional connections, physical connections, or circuit connections in an actual device.

[0046] Any use of examples or exemplary terms is merely intended to elaborate technical ideas and is not intended to limit the scope of the invention unless otherwise defined by the claims.

[0047] The laser processing device according to the embodiment described below with reference to the drawings can be applied to, for example, a stealth dicing type laser processing device that forms a modified area by focusing laser light inside a semiconductor wafer during a cutting process included in a semiconductor post-process, and causes the semiconductor wafer to be cut by cracks generated from the modified area.

[0048] Fig. 1 schematically illustrates a laser processing device (100) according to an embodiment. Fig. 2 is a plan view schematically illustrating an exemplary configuration of a processing object (1) of Fig. 1.

[0049] Referring to FIG. 1, a laser processing device (100) includes a laser light source (10) that generates laser light, a spatial light modulator (30) that modulates laser light provided from the laser light source (10) to form a processing modulation pattern, a focusing optical system (60) that focuses the laser light modulated by the processing modulation pattern in the spatial light modulator (30) onto a processing target (1), a relay lens optical system (50) that transmits an image of the processing modulation pattern formed by the spatial light modulator (30) to the entrance pupil of the focusing optical system (60), and a control unit (20) that controls the spatial light modulator (30) to modulate the laser light into the processing modulation pattern. The laser processing device (100) may be arranged so that the control unit (20) controls not only the spatial light modulator (30) but also the laser light source (10), or the laser light source (10) may be controlled by a separate control unit. FIG. 1 shows an example in which a control unit (20) is arranged to control a spatial light modulator (30) and a laser light source (10). Meanwhile, the laser processing device (100) may further include a stage (3) for moving a processing object (1) placed on a mounting surface of a support (5) and a stage position control unit (70) for controlling the position of the stage (3). In addition, the laser processing device (100) may further include an optical system position control unit (not shown) for adjusting the relative distance between a focusing optical system (60) and the processing object (1) so that the position of the focusing point of the laser light inside the processing object (1) is adjusted. The laser processing device (100) according to this embodiment can perform a processing process, for example, a cutting process, by irradiating the processing object (1) with laser light modulated into a processing modulation pattern by the spatial light modulator (30).

[0050] The processing object (1) may include, for example, a semiconductor wafer. The processing object (1) may include a semiconductor wafer made of a silicon semiconductor material or a semiconductor wafer made of another material. For example, referring to FIG. 2, the processing object (1) may include a semiconductor wafer having a plurality of functional elements (2) two-dimensionally arranged on the upper portion. However, the present invention is not limited thereto, and the semiconductor wafer included in the processing object (1) may not have a plurality of functional elements (2). The processing object (1) is not limited to a semiconductor wafer and may be made of various materials.

[0051] The plurality of functional elements (2) may include any one of a light-receiving element such as a photodiode, a light-emitting element such as a laser diode, and a circuit element such as a logic element or a memory element. However, the present invention is not limited thereto, and the plurality of functional elements (2) may include various types of elements other than the above-described elements. By the laser processing device (100) according to the embodiment, the object to be processed (1) may be cut along a cutting line (L) that demarcates an area in which the plurality of functional elements (2) are provided. The cutting line (L) may include a structure in which a plurality of first lines extending in a first direction and arranged parallel to a second direction perpendicular to the first direction and a plurality of second lines extending in a second direction and arranged parallel to the first direction intersect each other. In this case, the first direction and the second direction may be perpendicular to each other. However, the present invention is not limited thereto, and the first direction and the second direction may not be perpendicular to each other.

[0052] The laser light source (10) can emit pulsed laser light that is transparent to the object to be processed (1). In addition, the laser light source (10) can emit pulsed laser light that has conditions under which multiphoton absorption can occur within the object to be processed (1) when the laser light is focused within the object to be processed (1). The conditions under which multiphoton absorption can occur are widely known in the stealth dicing technology field, and therefore, a description thereof is omitted herein.

[0053] A spatial light modulator (SLM) (30) can spatially modulate laser light incident from a laser light source (10) to form a processing modulation pattern. The spatial light modulator (30) can be controlled by a control unit (20) to modulate the laser light with a set processing modulation pattern. Under the control of the control unit (20), the laser light modulated with the processing modulation pattern in the spatial light modulator (30) can be focused on a plurality of focusing points at different depths within the processing target (1) by a focusing optical system (60).

[0054] The control unit (20) can control the spatial light modulator (30) to form a set processing modulation pattern. In addition, the control unit (20) can control the spatial light modulator (30) to adjust the processing modulation pattern according to the processing target (1) and / or the processing direction so that the position of the focusing point of the laser light is adjusted.

[0055] A reflective spatial light modulator (30) may be provided. As another example, a transmissive spatial light modulator (30) may be provided. In FIG. 1 and FIGS. 7 and 8 described below, an example in which the spatial light modulator (30) is a reflective spatial light modulator is described and illustrated, but the present invention is not limited thereto.

[0056] The spatial light modulator (30) may be configured to enable light control, for example, on a pixel-by-pixel or sub-pixel-by-pixel basis. The spatial light modulator (30) reflects and outputs incident laser light, and may include, for example, a reflective liquid crystal on silicon (LCOS) spatial light modulator to modulate the laser light into a processing modulation pattern under the control of the control unit (20). In the reflective liquid crystal spatial light modulator, the arrangement direction of liquid crystal molecules changes according to an electric field formed in a liquid crystal layer for each pixel or sub-pixel, and accordingly, the phase of the laser light passing through the liquid crystal layer may vary for each pixel. A processing modulation pattern can be formed by such phase modulation.

[0057] As another example, the spatial light modulator (30) may include a DLP (Digital Light Processing) type spatial light modulator having a two-dimensional array of digital micromirror devices (DMDs) that enable light control on a pixel-by-pixel or sub-pixel basis. The DLP type spatial light modulator can form a processing modulation pattern by turning light on / off on a pixel-by-pixel or sub-pixel basis, or by adjusting the direction of propagation of reflected light and the resulting divergence angle to vary.

[0058] The spatial light modulator (30) can form a processing modulation pattern so that the laser light modulated with the processing modulation pattern can be focused on a plurality of focusing points at different depths inside the object to be processed (1). At this time, the laser light modulated with the processing modulation pattern can include a light component having a different refractive power with respect to the basic light component. The light component having a different refractive power is a light component defocused with respect to the basic light component, and may correspond to a light component having a negative refractive power and / or a positive refractive power. The basic light component represents a light component whose refractive power is not adjusted by the spatial light modulator (30), and the defocused light component may represent a light component whose refractive power is adjusted by the spatial light modulator (30). The focusing point where the light component having a different refractive power is focused can be located in front of or behind the focusing point where the basic light component is focused.

[0059] As an example, the spatial light modulator (30) can be controlled by the control unit (20) so that the laser light modulated with the processing modulation pattern includes a fundamental light component and a light component having a different refractive power from the fundamental light component. The light component having a different refractive power may be a light component exhibiting positive or negative refractive power. In this case, one of the first and second focusing points (P1) (P2) in FIG. 3 may be, for example, a focusing point of the fundamental light component, and the other may be a focusing point of a defocused light component exhibiting negative or positive refractive power with respect to the fundamental light component.

[0060] As another example, the spatial light modulator (30) can be controlled by the control unit (20) so that the laser light modulated with the processing modulation pattern includes a defocused light component that exhibits positive refractive power and a defocused light component that exhibits negative refractive power. In this case, one of the first and second focusing points (P1) (P2) in FIG. 3 can be, for example, a focusing point of a defocused light component that exhibits negative refractive power, and the other can be a focusing point of a defocused light component that exhibits positive refractive power.

[0061] As another example, the spatial light modulator (30) may be controlled by the control unit (20) to form a processing modulation pattern that focuses laser light on three or more focusing points at different depths inside the processing object (1). In this case, the laser light modulated by the processing modulation pattern can be focused by the focusing optical system (60) on three or more focusing points at different depths inside the processing object (1). For example, among the three focusing points, the focusing point at the middle depth may be a focusing point of the fundamental light component, the focusing point at the first depth may be a focusing point of the fundamental light component defocused to exhibit, for example, positive refractive power, and the focusing point at the third depth may be a focusing point of the fundamental light component defocused to exhibit, for example, negative refractive power.

[0062] Figure 3 shows an example in which laser light modulated with a processing modulation pattern set by a spatial light modulator (30) is focused on multiple focusing points inside a processing target (1) by a focusing optical system (60).

[0063] Referring to FIG. 3, when the laser light modulated with the set processing modulation pattern is focused inside the processing object (1) by the focusing optical system (60), the modulated laser light can be focused on a plurality of focusing points at different depths, for example, a first focusing point (P1) and a second focusing point (P2). The laser light can be absorbed at each of the plurality of focusing points, for example, the first focusing point (P1) and the second focusing point (P2), to form a first modified region (4a) and a second modified region (4b). FIG. 3 shows an example in which the first focusing point (P1) is located at a first depth (d1) and the second focusing point (P2) is located at a second depth (d2) from the upper surface (1a) of the processing object (1). At this time, the first depth (d1) and the second depth (d2) are different from each other. As exemplarily shown in Fig. 3, laser light modulated into a processing modulation pattern by a spatial light modulator (30) can be focused by a focusing optical system (60) onto first and second focusing points (P1) (P2) at a first depth (d1) and a second depth (d2) from the upper surface (1a) of the processing target (1), whereby a first modified region (4a) and a second modified region (4b) can be formed at the first focusing point (P1) and the second focusing point (P2), respectively. By moving the processing target (1), an array of first modified regions (4a) and an array of second modified regions (4b) can be formed at the first depth (d1) and the second depth (d2), respectively. In FIG. 3 and the following description, the first modified region (4a) and the second modified region (4b) are described and illustrated as being formed at the first focusing point (P1) and the second focusing point (P2) positions of different first depths (d1) and second depths (d2), respectively, but are not limited thereto. The number of focusing points of different depths and the number of modified regions resulting from them may be three or more.

[0064] In this way, the spatial light modulator (30) can form a processing modulation pattern so that the laser light can be focused on multiple focusing points at different depths within the processing target (1). At this time, the laser light modulated by the processing modulation pattern can include a light component having a different refractive power with respect to the basic light component.

[0065] Meanwhile, when the laser light modulated by the spatial light modulator (30) forming the processing modulation pattern is focused on the inside of the processing target (1) by the focusing optical system (60), a modified region can be formed at each of the plurality of focusing points at different depths where the laser light is focused. Since the modified region can be discontinuously formed along the cutting line (L) according to the movement of the processing target (1), a plurality of modified region arrays at different depths can be formed along the cutting line (L). Each of the plurality of modified region arrays can form a cutting line.

[0066] For example, during one duty of laser light irradiation for forming a modified region, a first modified region (4a) and a second modified region (4b) can be formed at the first focus point (P1) and the second focus point (P2) of the first depth (d1) and the second depth (d2) inside the object to be processed (1), respectively. When the object to be processed (1) is moved along the line to be cut (L) while the laser light is irradiated on the line to be cut (L), an array of first modified regions (4a) and an array of second modified regions (4b) can be formed at the first depth (d1) and the second depth (d2) inside the object to be processed (1), respectively, corresponding to the line to be cut (L). Here, one duty is a time for which laser light is irradiated to form the first modified region (4a) and the second modified region (4b) at one location. During one duty, the laser light can be irradiated once in a pulse form or multiple times. In addition, the spacing between the modified regions in the first modified region (4a) array and the second modified region (4b) array may depend on the moving speed of the object to be processed (1) and the duty interval for irradiating the pulsed laser light. The moving speed of the object to be processed (1) and the duty interval for irradiating the pulsed laser light may be determined as an interval at which the object to be processed (1) can be cut along the cutting line (L) by cracks generated during the cooling process of the first modified region (4a) and the second modified region (4b) that are discontinuously arranged along the cutting line (L). Cracks generated during the cooling process of the first modified region (4a) and the second modified region (4b) that are adjacent to each other in the depth direction may meet each other.

[0067] Meanwhile, the first modified region (4a) and the second modified region (4b), which are formed simultaneously and adjacent to each other in the depth direction during one duty, may exist in a state spaced apart from each other or may be combined in the depth direction to form an enlarged modified region.

[0068] When the first modified region (4a) and the second modified region (4b) adjacent in the depth direction are spaced apart from each other, the arrangement of the first modified region (4a) and the arrangement of the second modified region (4b) can each form a cutting line. In this case, during one machining process along the cutting line (L), cutting lines can be simultaneously formed at the first depth (d1) and the second depth (d2) of the object to be processed (1), respectively, so that the number of times the cutting process is repeated to sequentially form a plurality of cutting lines at different depths can be reduced, and thus the cutting process time can be shortened.

[0069] In addition, as another example, the first modified region (4a) and the second modified region (4b) which are adjacent to each other in the depth direction may be combined with each other to form a single enlarged modified region (4' in FIG. 4). In this case, the arrangement of the first modified region (4a) and the arrangement of the second modified region (4b) also form an arrangement of modified regions enlarged in the depth direction, whereby the enlarged modified regions can form a single cutting line in which the arranged discontinuously along the cutting line (L) are arranged. In this case as well, during a single machining process along the cutting line (L), corresponding to forming a plurality of cutting lines sequentially at different depths through repetition of the cutting process, a cutting line including an arrangement of enlarged modified regions inside the processing object (1) can be formed, so that the cutting process time can be shortened.

[0070] Therefore, according to the laser processing device (100) according to the embodiment, by modulating the laser light to form a processing modulation pattern by the spatial light modulator (30), during a single cutting process performed along the cutting line (L), a plurality of cutting lines can be simultaneously formed at different depths within the processing target (1), or a single cutting line can be formed by an array of enlarged modified areas, so that the number of times the cutting process is repeated can be reduced, and thus the cutting process time can be shortened.

[0071] Fig. 4 is intended to explain the principle of a crack (c1) occurring inside the processing target (1) of Fig. 3. In Fig. 4, reference numeral 4' indicates an enlarged modified area with a dotted line when the first modified area (4a) and the second modified area (4b) are connected to each other.

[0072] Referring to Fig. 4, cracks (c1) may be generated based on the first and second modified regions (4a) (4b), respectively, or based on the expanded modified region (4') formed by connecting the first and second modified regions (4a) (4b). The cracks (c1) may occur during the cooling process of the modified region heated by laser processing. The plurality of cracks (c1) may extend to reach the upper surface (1a) and the lower surface (1b) of the object to be processed (1). However, the present invention is not limited thereto, and the cracks (c1) may extend even when an external stress acts on the modified region. The object to be processed (1) may be cut based on the plurality of cracks (c1).

[0073] Meanwhile, according to the laser processing device (100) according to the embodiment, the processing process may be performed two or more times along the cutting line (L) while varying the depth at which the modified area is formed so as to generate sufficient cracks for cutting the object to be processed (1). For example, if laser processing is performed while changing the distance between the light-collecting optical system (60) and the object to be processed (1) by the optical system position control unit, the position at which the cutting line is formed inside the object to be processed (1) in the optical axis direction (z direction) can be changed. At this time, each cutting line may include a plurality of cutting lines by an arrangement of a plurality of modified areas (4a) (4b) that are formed simultaneously as described with reference to FIG. 3, for example, or a cutting line by an arrangement of an enlarged modified area (4') as described with reference to FIG. 4. For example, in the case where two cutting lines are formed during one processing process as in Fig. 3, if the processing process is performed twice, four cutting lines can be formed at different locations in the optical axis direction (z direction) inside the processing object (1). In addition, in the case where a cutting line is formed by an array of enlarged modified regions (4') as in Fig. 4, if the processing process is performed twice, two processing lines, each formed over a wide range at different locations in the optical axis direction (z direction) inside the processing object (1), can be formed.

[0074] Referring back to FIG. 1, according to the laser processing device (100) according to the embodiment, the relay lens optical system (50) can transmit laser light modulated with a processing modulation pattern by the spatial light modulator (30) to the focusing optical system (60). The relay lens optical system (50) can be arranged to transmit an image of the processing modulation pattern formed by the spatial light modulator (30) to the entrance pupil of the focusing optical system (60). To this end, the relay lens optical system (50) can be positioned between the spatial light modulator (30) and the focusing optical system (60).

[0075] The relay lens optical system (50) includes a first lens group (51), a second lens group (56), and a field lens (55) between the first lens group (51) and the second lens group (56), and can be arranged so that the processing modulation pattern forming surface of the spatial light modulator (30) and the entrance pupil of the light collecting optical system (60) form an imaging relationship.

[0076] According to the relay lens optical system (50) according to the embodiment, each of the first lens group (51) and the second lens group (56) may include two or more lenses. For example, each of the first lens group (51) and the second lens group (56) may include a lens having positive refractive power and a lens having negative refractive power. In addition, the relay lens optical system (50) may be arranged to form, for example, a 3f lens system.

[0077] Fig. 5 schematically shows an embodiment of the relay lens optical system (50) of Fig. 1.

[0078] Referring to FIG. 5, the relay lens optical system (50) may be configured such that the first lens group (51) and the second lens group (56) each include two lenses, and the field lens (55) includes, for example, one lens. The first lens group (51) may be configured with two lenses, for example, including a first lens (52) having positive refractive power and a second lens (53) having negative refractive power. The field lens (55) may be configured with, for example, positive refractive power. The second lens group (56) may be configured with two lenses, for example, including a first lens (57) having positive refractive power and a second lens (58) having negative refractive power.

[0079] As exemplarily shown in Fig. 5, the relay lens optical system (50) can form a 3f lens system by placing a field lens (55) between the first lens group (51) and the second lens group (56).

[0080] For example, the relay lens optical system (50) can be designed so that the focal length of the first lens group (51) is f1, the focal length of the second lens group (56) is f2, the distance between the center of the first lens group (51) and the center of the second lens group (56) is f1+f2, and the field lens (55) is positioned at f1 from the center of the first lens group (51) and at f2 from the center of the second lens group (56). In this case, the distance from the object surface (S1), for example, the processing modulation pattern forming surface (S1) of the spatial light modulator (30), to the center of the first lens group (51) can be f1 / 2, and the distance from the center of the second lens group (56) to the image surface (S2), for example, the entrance pupil (S2) of the light-gathering optical system (60) can be f2 / 2, so that the relay lens optical system (50) can form a 3f lens unit system.

[0081] In this way, by configuring the relay lens optical system (50) with a structure in which the field lens (55) is arranged between the first lens group (51) and the second lens group (56), a 3f lens unit system can be formed. As a result, the optical path length between the processing modulation pattern forming surface (S1) of the spatial light modulator (30) and the entrance pupil (S2) of the light-gathering optical system (60) can be reduced, so that the optical system of the laser processing device (100) can be reduced, and the overall size of the laser processing device (100) can be reduced. Here, the processing modulation pattern forming surface (S1) may correspond to, for example, the input / output surface (30a) of the spatial light modulator (30) or a surface including any point within the thickness range of the spatial light modulator (30).

[0082] FIG. 6A is for explaining the optical path length reduction effect of the relay lens optical system (50) according to the embodiment. FIG. 6B shows the optical path length of the relay lens optical system (50') of the comparative example, and shows the case where the relay lens optical system (50') of the comparative example is composed of the first lens group (51) and the second lens group (56) of the relay lens optical system (50) of the embodiment. FIG. 6A exemplarily shows the optical path in the relay lens optical system (50) according to the embodiment when the effective focal lengths of the first lens group (51) and the second lens group (56) are the same, and FIG. 6B exemplarily shows the optical path in the relay lens optical system (50') of the comparative example when the effective focal lengths of the first lens group (51) and the second lens group (56) are the same, and shows an example in which the relay lens optical system (50') of the comparative example configures a telecentric lens optical system.

[0083] For comparison, FIGS. 6A and 6B show examples in which the effective focal lengths of the first lens group (51) and the second lens group (56) are the same as f. In FIGS. 6A and 6B, A represents the center position of the first lens group (51), B represents the center position of the second lens group (56), and C represents the center position of the field lens (55). In addition, in FIGS. 6A and 6B, reference numerals S1 and S1' represent entrance pupils, and S2 and S2' represent exit pupils. The entrance pupils (S1 and S1') may correspond to the processing modulation pattern forming surface of the spatial light modulator (30), and the exit pupils (S2 and S2') may correspond to the entrance pupils of the light-gathering optical system (60).

[0084] As shown in Fig. 6a, the relay lens optical system (50) of the embodiment may include a first lens group (51), a second lens group (56), and a field lens (55) at an intermediate position from the centers of the first lens group (51) and the second lens group (56). Accordingly, according to the relay lens optical system (50) of the embodiment, the entrance pupil (S1) may be positioned at a distance of f / 2 from the first lens group (51), and the exit pupil (S2) may be positioned at a distance of f / 2 from the second lens group (56).

[0085] On the other hand, as shown in Fig. 6b, the relay lens optical system (50') of the comparative example may be composed of a first lens group (51) and a second lens group (56). Accordingly, according to the relay lens optical system (50') of the comparative example, the entrance pupil (S1') is located at a distance of f from the first lens group (51), and the exit pupil (S2') is located at a distance of f from the second lens group (56).

[0086] As can be seen from the comparison of FIGS. 6A and 6B, the relay lens optical system (50) according to the embodiment can reduce the optical path length from 4f to 3f by further providing a field lens (55) between the first lens group (51) and the second lens group (56) compared to the relay lens optical system (50') of the comparative example. In addition, as can be seen from the comparison of the relay lens optical system (50) according to the embodiment of FIG. 9A, which will be described later, and the relay lens optical system (50') of the comparative example of FIG. 12A, the relay lens optical system (50') of the comparative example requires a larger number of lenses when applying an optical system with a telecentric lens configuration than when not doing so. However, in the relay lens optical system (50) according to the embodiment, the field lens (55) replaces this role, so the number of lenses and the optical path length can be reduced more effectively.

[0087] In this way, according to the relay lens optical system (50) according to the embodiment, by further providing a field lens (55) between the first lens group (51) and the second lens group (56), the optical path length can be reduced, thereby reducing the optical system size and, accordingly, the overall size of the laser processing device (100).

[0088] Meanwhile, FIG. 5 shows an example in which each of the first lens group (51) and the second lens group (56) consists of two lenses, but this is merely exemplary and the embodiment is not limited thereto. In addition, FIG. 5 shows an example in which the field lens (55) consists of one lens, but the embodiment is not limited thereto. For example, the first lens group (51), the second lens group (56) and the field lens (55) arranged therebetween can be designed in various ways so that the relay lens optical system (50) forms a 3f lens unit system.

[0089] This relay lens optical system (50) can transmit the image of the processing modulation pattern formed by the spatial light modulator (30) to the entrance pupil of the focusing optical system (60). The focusing optical system (60) can focus the laser light transmitted through the relay lens optical system (50) on the inside of the processing target (1) mounted on the support (5) to form a focusing point.

[0090] At this time, as described above, multiple focusing points of the laser light can be obtained at different depths within the processing target (1) according to the processing modulation pattern formed by the spatial light modulator (30). Accordingly, since a modified region can be formed at each of the multiple focusing points, modified regions spaced apart from each other in the depth direction can be formed, or modified regions formed at the multiple focusing points can be connected to each other to form a modified region expanded in the depth direction.

[0091] For example, as in FIG. 3, a first focusing point (P1) and a second focusing point (P2) are formed at a first depth (d1) and a second depth (d2) inside the processing target (1), so that a first modified region (4a) and a second modified region (4b) can be formed simultaneously at the first depth (d1) and the second depth (d2).

[0092] Accordingly, by moving the stage (3) along the cutting line (L) under the control of the stage position control unit (70) to move the processing object (1) and focus the laser light inside the processing object (1), an arrangement in which the first modified area (4a) is discontinuously formed at the first focusing point (P1) position of the first depth (d1) along the cutting line (L) inside the processing object (1) and an arrangement in which the second modified area (4b) is discontinuously formed at the second focusing point (P2) position of the second depth (d2) different from the first depth (d1) can be formed.

[0093] That is, by moving the processing target (1), an array of a first modified region (4a) at a first depth (d1) and an array of a second modified region (4b) at a second depth (d2) can be formed. At this time, the first modified region (4a) and the second modified region (4b), which are simultaneously formed adjacent to each other in the depth direction during one duty, can exist in a state spaced apart from each other, or can be combined in the depth direction to form an enlarged modified region (4').

[0094] Therefore, according to the laser processing device (100) according to the embodiment, during one processing process along the cutting line (L), a plurality of cutting lines can be formed in the depth direction inside the processing target (1), or one cutting line including an array of enlarged modified areas (4') can be formed, so that the number of times the cutting process is repeated along the cutting line (L) can be reduced, and thus the cutting process time can be shortened.

[0095] Meanwhile, referring back to FIG. 1, the focusing optical system (60) may include an objective lens (61) that focuses the laser light transmitted through the relay lens optical system (50) onto the inside of the processing target (1). In addition, the laser processing device (100) according to the embodiment may further include a reflection mirror (101) between the relay lens optical system (50) and the objective lens (61) of the focusing optical system (60). When the focusing optical system (60) includes only the objective lens (61), the entrance pupil of the focusing optical system (60) through which the image of the processing modulation pattern is transmitted may correspond to the entrance pupil of the objective lens (61).

[0096] Meanwhile, FIGS. 7 and 8 show other embodiments of optical system configurations that can be applied to the laser processing device (100) of FIG. 1. In FIGS. 1, 7, and 8, the spacing between optical components, the size and shape of the optical components, etc. are only shown as examples for the purpose of explaining the arrangement relationship, and the embodiments are not limited thereto.

[0097] Referring to FIGS. 7 and 8, the focusing optical system (60) may further include a beam expander (65) for expanding the beam width of the laser light between the relay lens optical system (50) and the objective lens (61). The beam expander (65) may be disposed between the relay lens optical system (50) and the reflecting mirror (101), as exemplarily shown in FIG. 7. In addition, the beam expander (65) may be disposed between the reflecting mirror (101) and the objective lens (61), as exemplarily shown in FIG. 8.

[0098] As exemplarily shown in FIGS. 7 and 8, when the focusing optical system (60) further includes a beam expander (65), the entrance pupil of the focusing optical system (60) through which the image of the processed modulation pattern is transmitted may correspond to the entrance pupil of the beam expander (65).

[0099] Meanwhile, FIG. 8 shows an example of an optical system configuration that can be applied to the laser processing device (100) of FIG. 1. Compared to FIG. 1 and FIG. 7, there is a difference not only in the arrangement of the beam expander (65), but also in the arrangement of the spatial light modulator (30).

[0100] Referring to FIG. 8, the laser processing device (100) may be arranged so that, when the direction in which the laser light emitted from the laser light source (10) travels or the direction perpendicular thereto is referred to as the first traveling direction, the spatial light modulator (30) is arranged to be parallel to the first traveling direction. To this end, the laser processing device (100) may further include an optical member (40) that is arranged to cause the laser light to be obliquely incident to the spatial light modulator (30) and to cause the laser light modulated and reflected by the spatial light modulator (30) to travel in a direction parallel to the first traveling direction. The traveling direction of the laser light incident from the laser light source (10) to the optical member (40) may correspond to the first traveling direction.

[0101] Fig. 8 shows an example in which an optical member (40) has a triangular cross-sectional structure. The optical member (40) may include a first surface (41) and a second surface (43) that are angled to each other and are positioned obliquely with respect to the spatial light modulator (30), and a third surface (45) that is positioned on the opposite side from the spatial light modulator (30).

[0102] The optical member (40) may have, for example, a prism structure, in which case the first surface (41) and the second surface (43) may be refracting / transmitting surfaces, and the third surface (45) may be an internal reflecting surface. The third surface (45) may be arranged, for example, parallel to the spatial light modulator (30). In this way, when the optical member (40) has a prism structure, the laser light incident on the optical member (40) along the first propagation direction may be refracted / passed through the first surface (41), internally reflected at the third surface (45), refracted / passed through the first surface (41) again, and then incident on the spatial light modulator (30). The laser light modulated and reflected to form a processed modulation pattern in the spatial light modulator (30) is refracted / passes through the second surface (43), is internally reflected at the third surface (45), and is refracted / passes through the third surface (45) again to proceed along the first direction of travel and can be transmitted to the relay lens optical system (50).

[0103] As another example, the optical member (40) may have a first surface (41) and a second surface (43) that may be a first reflective surface and a second reflective surface, respectively. In this case, the first surface (41) may be configured to reflect laser light incident in the first propagation direction and cause the laser light to be obliquely incident on the spatial light modulator (30), and the second surface (43) may be configured to reflect laser light that is modulated and reflected to form a processed modulation pattern in the spatial light modulator (30) and cause the laser light to propagate along the first propagation direction. The angle formed by the first surface (41) and the second surface (43) may be determined so that such a propagation path is obtained.

[0104] Meanwhile, in order to properly arrange the laser processing device (100) according to the embodiment and to secure the necessary optical path without enlarging the size of the optical system, a reflection mirror (110) (111) (113) (115) may be further applied as shown in FIGS. 1, 7, and 8. Meanwhile, in FIGS. 1, 7, and 8, the first lens group (51) and the second lens group (56) of the relay lens optical system (50), the beam expander (65) of the light-gathering optical system (60), and the objective lens (61) are illustrated as single lenses, but this is merely an example and does not limit the embodiment. As shown as an example in FIG. 9b described below, the objective lens (61) may be formed of a plurality of lenses, and the beam expander (65) may also be formed of a plurality of lenses.

[0105] Referring back to FIG. 1, the stage position control unit (70) can control the movement of the stage (3) connected to the support (5) on which the workpiece (1) is placed. The stage (3) can be configured to be able to move in a two-dimensional plane (xy plane). The stage position control unit (70) can control the movement of the stage (3) on the two-dimensional plane.

[0106] Meanwhile, as described above, in the case where the optical system position control unit is further included, the optical system position control unit can change the position of the focusing optical system (60), for example, the objective lens (61), in the optical axis direction (z direction), for example. As another example, the optical system position control unit can change the position of the entire optical system of the laser processing device (100) or the focusing optical system (60) including the objective lens (61) and the beam expander (65) in the optical axis direction (z direction). As a result, a cutting line can be formed at a set depth from the upper surface (1a) of the processing target (1), and the depth of cutting line formation can also be changed.

[0107] FIGS. 9A and 9B schematically show an optical path in a relay lens optical system (50) according to an embodiment and an entire lens optical system of a laser processing device (100) including the same. Table 1 of FIG. 10 shows design data and lens material and refractive power of the relay lens optical system (50) according to the embodiment of FIG. 9A. FIGS. 11A, 11B, and 11C show MTF performance, aberrations (chromatic aberration, astigmatism, distortion), and ray aberrations of the relay lens optical system (50) according to an embodiment formed with the design data of Table 1 shown in FIG. 10 and the entire lens optical system of a laser processing device (100) including the same, respectively.

[0108] Referring to Table 1 of FIGS. 9A, 9B and 10, in the relay lens optical system (50) according to the embodiment, the first lens group (51: Lens1) may include two lenses (52: G1) (53: G2), the field lens (55: Field Lens) may include one lens (G1), and the second lens group (56: Lens2) may include two lenses (G1) (G2). The first lens group (51) may include, for example, a lens (52: G1) having positive refractive power and a lens (53: G2) having negative refractive power. The field lens (55) may include, for example, a lens (G1) having positive refractive power. The second lens group (56) may include, for example, a lens (57: G1) having positive refractive power and a lens (58: G1) having negative refractive power. In Table 1, G1 represents a lens with positive refractive power, and G2 represents a lens with negative refractive power.

[0109] Meanwhile, as illustrated in FIG. 9b, the focusing optical system (60) may include a beam expander (65) and an objective lens (61), and the beam expander (65) may be composed of a plurality of lenses, and the objective lens (61) may be composed of a plurality of lenses. When the focusing optical system (60) includes a beam expander (65) and an objective lens (61) as illustrated in FIG. 9b, the entrance pupil of the focusing optical system (60) may correspond to the entrance pupil of the beam expander.

[0110] In Fig. 9b, the starting point S1 representing the length of the optical system represents the entrance pupil of the relay lens optical system (50) and may correspond to the processing modulation pattern forming surface of the spatial light modulator (30) described above. Point S2 may correspond to the exit pupil of the relay lens optical system (50) and the entrance pupil of the condensing optical system (60). Point I is the focus position of the objective lens (61) of the condensing optical system (60) and may correspond to the condensing point of the basic light component inside the processing target (1) described above. The lens optical system of the laser processing device (100) may be composed of the relay lens optical system (50) and the condensing optical system (60), and the length of the lens optical system of the laser processing device (100) may correspond to the distance (①) from the above-mentioned starting point S1 to point I.

[0111] When designing a relay lens optical system (50) with the data of Table 1 shown in FIG. 10, it can be seen that the relay lens optical system (50) of the embodiment and the entire lens optical system of the laser processing device (100) including the same exhibit good MTF performance, aberration (chromatic aberration, astigmatism, distortion), and ray aberration, as shown in FIGS. 11a, 11b, and 11c. In addition, when designing a relay lens optical system (50) with the data of Table 1 shown in FIG. 10, the optical path length (the distance (②) from the starting point S1 to the point S2) of the relay lens optical system (50) of the embodiment may be about 913.356 mm, and the optical path length (the distance (①) from the starting point S1 to the point I) of the entire lens system of the laser processing device (100) may be about 1150 mm.

[0112] FIGS. 12a and 12b schematically show the optical path in the entire lens optical system of a comparative example relay lens optical system (50') designed to have similar optical performance to the relay lens optical system (50) according to the embodiment, and a laser processing device including the same. Table 2 of FIG. 13 shows the design data, lens material, and refractive power of the comparative example relay lens optical system (50') of FIG. 12a. FIGS. 14a, 14b, and 14c show the MTF performance, aberration (chromatic aberration, astigmatism, distortion), and ray aberration of the comparative example relay lens optical system (50') formed with the design data of Table 2, and the entire lens optical system of a laser processing device including the same, respectively.

[0113] Referring to FIGS. 12a, 12b and Table 2 of FIG. 13, the relay lens optical system (50') of the comparative example is composed of a first lens group (51': Lens1) and a second lens group (56': Lens2). The first lens group (51': Lens1) may be composed of three lenses (52': G1') (53': G2') (54': G3'), and the second lens group (56': Lens2) may be composed of three lenses (57': G1') (58': G2') (59': G3'). The first lens group (51') may be composed of a lens having positive refractive power (52': G1'), a lens having negative refractive power (53': G2'), and a lens having positive refractive power (54': G3'). The second lens group (56) may be composed of a lens having positive refractive power (57':G1'), a lens having negative refractive power (58':G2'), and a lens having positive refractive power (59':G3'). Meanwhile, the light-gathering optical system (60) may be the same as in Fig. 9b.

[0114] In Fig. 12b, the starting point S1' representing the length of the optical system, the entrance pupil of the relay lens optical system (50') of the comparative example, point S2' is the exit pupil of the relay lens optical system (50') of the comparative example, the entrance pupil of the condensing optical system (60), point S2', and point I' may correspond to the focus position of the objective lens (61) of the condensing optical system (60). The entire lens system of the laser processing device may be composed of the relay lens optical system (50') and the condensing optical system (60), and the optical path length (①') of the entire lens system of the laser processing device corresponds to the distance from the above-mentioned starting point S1' to point I'.

[0115] When designing a relay lens optical system (50') of a comparative example with the data of Table 2 shown in FIG. 13, it can be seen that the relay lens optical system (50') of a comparative example and the entire lens system of a laser processing device including the same exhibit good MTF performance, aberration (chromatic aberration, astigmatism, distortion), and ray aberration, as shown in FIGS. 14a, 14b, and 14c. In addition, when designing a relay lens optical system (50') of a comparative example with the data of Table 2 shown in FIG. 13, the optical path length (the distance (②') from the starting point S1' to the point S2') of the relay lens optical system (50') of a comparative example is about 1145.356 mm, and the optical path length (the distance (①') from the starting point S1' to the point I') of the entire lens system of the laser processing device is about 1382 mm.

[0116] In this way, the optical path length (②) of the relay lens optical system (50) of the embodiment is about 913.356 mm, and the optical path length (①) of the entire lens system of the laser processing device (100) including it is about 1150 mm, whereas the optical path length (②') of the relay lens optical system (50') of the comparative example is 1145.356 mm, and the optical path length (①') of the entire lens system of the laser processing device including it is about 1382 mm. From this, it can be confirmed that when the relay lens optical system (50) of the embodiment is applied, the optical path length can be reduced, and thus the overall size of the laser processing device (100) can be reduced. Furthermore, according to the relay lens optical system (50) according to the embodiment, by providing the field lens (55) between the first lens group (51) and the second lens group (56), it can be confirmed that the number of lenses is reduced compared to the relay lens optical system (50') of the comparative example.

[0117] As described above, according to the relay lens optical system (50) according to the embodiment and the laser processing device (100) applying the same, the optical path length and the entire optical system can be reduced, thereby reducing the size of the laser processing device (100).

[0118] Although the above-described relay lens optical system (50) and the laser processing device (100) including the same have been described with reference to the embodiments illustrated in the drawings, these are merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible from this. Therefore, the disclosed embodiments should be considered from an illustrative rather than a limiting perspective. The scope of the present specification is indicated by the claims, not the foregoing description, and all differences within a scope equivalent thereto should be interpreted as being included.

Claims

1. A laser light source that generates laser light; A spatial light modulator that modulates laser light provided from the laser light source to form a processing modulation pattern; A focusing optical system that focuses the laser light modulated by the above spatial light modulator onto a processing target; A relay lens optical system positioned between the spatial light modulator and the condensing optical system, configured to transmit an image of a processed modulation pattern formed by the spatial light modulator to the entrance pupil of the condensing optical system, the relay lens optical system including a first lens group, a second lens group, and a field lens between the first lens group and the second lens group; A laser processing device comprising a control unit that controls the spatial light modulator to modulate laser light with the above processing modulation pattern.

2. A laser processing device according to claim 1, wherein each of the first lens group and the second lens group includes two or more lenses.

3. In the second paragraph, each of the first lens group and the second lens group includes a first lens having positive refractive power and a second lens having negative refractive power, The above field lens is a laser processing device designed to have positive refractive power.

4. In the second paragraph, the relay lens optical system is a laser processing device configured to form a 3f lens unit.

5. In the first paragraph, the spatial light modulator, A laser processing device that forms the processing modulation pattern under the control of the control unit so that the laser light modulated by the processing modulation pattern is focused on a plurality of focusing points at different depths inside the processing target by the focusing optical system.

6. In the fifth paragraph, the laser light modulated with the processing modulation pattern is A laser processing device that includes a light component having a different refractive power than the basic light component.

7. In the first paragraph, the spatial light modulator is a laser processing device including a reflective spatial light modulator.

8. In the 7th paragraph, an optical member is further included; When the direction of propagation of the laser light incident from the laser light source to the optical member is referred to as the first propagation direction, A laser processing device in which the optical member is arranged to cause the laser light to be incident obliquely onto the spatial light modulator and to cause the laser light modulated and reflected by the spatial light modulator to proceed in a direction parallel to the first propagation direction, and the internal reflection surface is a prism structure parallel to the spatial light modulator.

9. In the first paragraph, the light-gathering optical system, A laser processing device including an objective lens that focuses the incident laser light onto a processing target.

10. In the 9th paragraph, the light-gathering optical system, A laser processing device further comprising a beam expander provided between the relay lens optical system and the objective lens to expand the beam width of the laser light.

11. In the 10th paragraph, a reflection mirror is further included between the relay lens optical system and the objective lens; The above beam expander is a laser processing device arranged between the relay lens optical system and the reflective mirror or between the reflective mirror and the objective lens.

12. In any one of paragraphs 1 to 11, A stage configured to be capable of two-dimensional plane movement; and A laser processing device further comprising a stage position control unit for controlling two-dimensional plane movement of the stage.

13. A laser light source that generates laser light; A reflective spatial light modulator that modulates laser light provided from the laser light source to form a processing modulation pattern; A focusing optical system including an objective lens that focuses the modulated laser light from the above reflective spatial light modulator onto a processing target; A relay lens optical system positioned between the reflective spatial light modulator and the condensing optical system, configured to transmit an image of a processed modulation pattern formed by the reflective spatial light modulator to an entrance pupil of the condensing optical system, the relay lens optical system including a first lens group, a second lens group, and a field lens between the first lens group and the second lens group; A stage configured to be capable of two-dimensional plane movement; A stage position control unit that controls the two-dimensional plane movement of the stage; A laser processing device including a control unit that controls the spatial light modulator to modulate laser light with the above processing modulation pattern.

14. A laser processing device in accordance with claim 13, wherein each of the first lens group and the second lens group includes two or more lenses.

15. In the 14th paragraph, each of the first lens group and the second lens group includes a first lens having positive refractive power and a second lens having negative refractive power, The above field lens is a laser processing device designed to have positive refractive power.

16. In the 14th paragraph, the relay lens optical system is a laser processing device configured to form a 3f lens unit.

17. In the 13th paragraph, the spatial light modulator, A laser processing device that forms the processing modulation pattern under the control of the control unit so that the laser light modulated by the processing modulation pattern is focused on a plurality of focusing points at different depths inside the processing target by the focusing optical system.

18. In the 17th paragraph, the laser light modulated with the processing modulation pattern is A laser processing device that includes a light component having a different refractive power than the basic light component.

19. In the 13th paragraph, a reflection mirror is further included between the relay lens optical system and the objective lens; A laser processing device wherein the above-mentioned light-gathering optical system further includes a beam expander provided between the relay lens optical system and the reflection mirror or between the reflection mirror and the objective lens to expand the beam width of the laser light.

20. In any one of claims 13 to 19, further comprising an optical member; The above optical member, A laser processing device in which the direction in which the laser light incident from the laser light source to the optical member is propagated is referred to as a first propagation direction, the laser light is incident obliquely onto the spatial light modulator, and the laser light modulated and reflected by the spatial light modulator is propagated in a direction parallel to the first propagation direction, and the internal reflection surface is a prism structure parallel to the spatial light modulator.

Images