Laser processing device and projection optical system of laser processing device

Abstract

To provide a laser processing device for scanning a linear beam, which can appropriately correct a projection image, with respect to expansion and contraction of a work-piece such as a substrate.SOLUTION: A laser processing device 100 comprises a one-sided variable magnification optical unit 32 composed of one pair of lenses in which a convex cylindrical lens and a concave cylindrical lens are oppositely arranged on a concave / convex surface. The one-sided variable magnification optical unit 32 is arranged so that a bus bar BM thereof extends along a scanning direction of a linear beam LB. A distance interval T along optical axis C of the convex cylindrical lens and the concave cylindrical lens is adjusted, so that projection magnifications of a projection optical system 30 can be corrected along a Y-axis in one direction, which can minify or magnify the projection image.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a laser processing apparatus that processes a workpiece such as a substrate by using a high-energy density laser beam, and more particularly to correction of a projected image in response to deformation of the substrate. [Background technology]

[0002] High-precision pattern formation is required for printed wiring boards, laminated PKG boards, etc., along with the miniaturization of patterns and high-density mounting. Ablation processing using a laser processing device is known as a processing method for forming fine vias and grooves (trenches) (see Patent Documents 1 and 2).

[0003] In this technique, high-energy density laser light from an excimer laser or similar is shaped into a line beam, which is then moved relative to a fixed mask (reticle) and projection lens to project a pattern of light onto a substrate, etc. Vias, grooves, etc. are formed in the substrate by instantaneously removing the material surface according to the mask pattern.

[0004] In laser processing equipment, high-density energy laser light is irradiated, so that workpieces such as substrates undergo thermal deformation and expansion and contraction during the processing process. In order to deal with such deformation of substrates, for example, an autofocus unit is provided in a scanning type laser processing equipment that irradiates a line-shaped beam while scanning a mask and substrate. The focal length is changed by the autofocus function according to the amount of expansion and contraction, and the projection magnification of the projection lens is adjusted (see Patent Document 3). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2020 / 003421 [Patent Document 2] Patent Publication No. 2021-49560 [Patent Document 3] JP 2008-221299 A Summary of the Invention [Problem to be solved by the invention]

[0006] In a laser processing apparatus that scans a line-shaped beam, the scanning direction for each processing area is determined from the viewpoints of the size of the processing area of ​​the substrate, optical characteristics such as the reduction magnification of the projection optical system, and improvement of throughput.

[0007] On the other hand, the direction and amount of expansion of the substrate varies depending on the influence of the laser processing process and the processes before and after it, and is not related to the scanning direction of the line beam. In addition, the direction and amount of expansion of the substrate are not necessarily constant over the entire substrate, and may differ depending on the area of ​​the substrate.

[0008] Therefore, in a laser processing device that scans a line-shaped beam, it is necessary to appropriately correct the projected image in response to expansion and contraction of a workpiece such as a substrate. [Means for solving the problem]

[0009] A laser processing apparatus according to one embodiment of the present invention includes a line beam forming optical system for shaping a laser beam into a line shape, a projection optical system for projecting the line beam transmitted through a mask onto a workpiece, and an optical unit in which a convex cylindrical lens and a concave cylindrical lens are arranged opposite each other. The optical unit is configured as an optical unit (hereinafter referred to as a single variable magnification optical unit) capable of changing and adjusting the projection magnification (imaging magnification) of the projection optical system 30 along one direction. The laser processing apparatus includes a scanning mechanism for scanning the line beam over the mask, the single variable magnification optical unit, and the projection optical system, and the single variable magnification optical unit transmits the line beam while changing its position, and the projection magnification of the projection optical system in one direction can be changed by changing the distance between the convex cylindrical lens and the concave cylindrical lens along the optical axis of the projection optical system. The single variable magnification optical unit can be provided within the projection optical system, or can be provided on an optical path outside the projection optical system.

[0010] The single-sided variable magnification optical unit is configured so that, when scanning the line-shaped beam, the line-shaped beam passes through the single-sided variable magnification optical unit while changing the incident surface position in the beam width direction. Therefore, the arrangement of the single-sided variable magnification optical unit taking into consideration the scanning direction of the line-shaped beam enables pattern correction according to the deformation direction and deformation amount of the substrate.

[0011] Various configurations can be applied to the single-sided variable magnification optical unit, and the curvature of the convex cylindrical lens and the curvature of the concave cylindrical lens can be set arbitrarily. For example, the single-sided variable magnification optical unit can be configured so that the curvatures are different from each other. In addition, the laser processing device is equipped with an actuator that can move the lens in the optical axis direction, and the projection magnification can be changed by driving the actuator.

[0012] Regarding the arrangement of the single-variable magnification optical unit in which the line-shaped beam moves on the optical surface during scanning, various arrangements can be applied according to the deformation direction, deformation amount, etc. of the substrate. For example, the single-variable magnification optical unit can be arranged so that its generatrix is ​​along the scanning direction of the line-shaped beam. Also, the single-variable magnification optical unit can be arranged so that its generatrix is ​​along a direction perpendicular to the scanning direction of the line-shaped beam. Furthermore, the single-variable magnification optical unit can be arranged so that its generatrix is ​​along a direction parallel to or inclined relative to the scanning direction of the line-shaped beam. The single-variable magnification optical unit can be selectively arranged so that the generatrix faces the above-mentioned direction in advance.

[0013] On the other hand, the laser processing device can be equipped with an actuator capable of rotating the single-sided variable magnification optical unit around the optical axis. The actuator may be used in combination with the above actuator, or a separate dedicated actuator may be provided. Before scanning with the line-shaped beam, the generatrix can be oriented in the above-mentioned direction to scan the line-shaped beam. Alternatively, during the scanning period, the direction of the generatrix can be changed at a predetermined timing depending on, for example, the deformation direction and amount of deformation of the substrate.

[0014] The laser processing apparatus may also include an optical unit (hereinafter referred to as an isotropic magnification correction optical unit) that is composed of one or more lenses and that can isotropically correct the projection magnification of the projection optical system. The isotropic magnification correction optical unit is configured as an optical unit that can adjust the projection magnification so as to maintain the scaling of the projected image. The projected image can be enlarged or reduced at any magnification in the scanning direction and in a direction perpendicular to the scanning direction. In this case, the single variable magnification optical unit can be disposed on the mask side of the isotropic magnification correction optical unit along the optical axis of the projection optical system.

[0015] In addition, the laser processing apparatus can be configured to change the distance between the convex cylindrical lens and the concave cylindrical lens by driving the actuator during the period in which the line-shaped beam is scanned over the single-magnification optical unit.

[0016] The projection optical system of the laser processing device according to another aspect of the present invention is a projection optical system of the laser processing device that projects a line-shaped beam transmitted through a mask onto a workpiece while scanning the line-shaped beam, and includes a single-sided variable magnification optical unit in which a convex cylindrical lens and a concave cylindrical lens are arranged opposite each other. The single-sided variable magnification optical unit is configured so that when the line-shaped beam is scanned, the line-shaped beam passes through the single-sided variable magnification optical unit while changing the position of the incident surface of the single-sided variable magnification optical unit in the beam width direction. The laser processing device can change the projection magnification in one direction by changing the distance between the convex cylindrical lens and the concave cylindrical lens along the optical axis. Effect of the Invention

[0017] According to the present invention, in a laser processing device that scans a line-shaped beam, a projected image can be appropriately corrected for expansion and contraction of a workpiece such as a substrate. [Brief description of the drawings]

[0018] [Figure 1] 1 is a schematic configuration diagram of a laser processing device according to a first embodiment. [Diagram 2] FIG. 1 is a schematic block diagram of a laser processing device. [Diagram 3] FIG. 2 is a schematic perspective view of a single-side variable magnification optical unit 32. [Figure 4] 3A and 3B are cross-sectional views of a single-side variable magnification optical unit 32 taken along the YZ direction and the XZ direction, respectively. [Diagram 5] 13A and 13B are diagrams illustrating correction of the projection magnification of a projected image by a single-sided variable magnification optical unit 32. [Figure 6] 13A and 13B are diagrams illustrating correction of the projection magnification of a projected image by a one-sided variable magnification optical unit 32 and an isotropic magnification correction optical unit 35. FIG. [Figure 7] FIG. 13 is a diagram showing a single-sided variable magnification optical unit of a laser processing apparatus according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, the laser processing apparatus according to the present embodiment will be described with reference to the drawings.

[0020] Fig. 1 is a schematic configuration diagram of a laser processing apparatus according to a first embodiment, and Fig. 2 is a schematic block diagram of the laser processing apparatus.

[0021] The laser processing apparatus 100 is a processing apparatus capable of forming a pattern on a substrate W by ablation processing, and includes a line beam forming unit 20, a projection optical system 30, a mask stage 40, and a processing stage 50. The line beam forming unit 20, the mask stage 40, and the processing stage 50 are mounted on an apparatus main body (not shown) and are movable relative to the apparatus main body. The mask M and the substrate W are mounted on the mask stage 40 and the processing stage 50, respectively. Here, the substrate W is formed of a resin substrate such as a printed circuit board.

[0022] A laser 10 installed near the main body of the apparatus oscillates a high energy density laser beam. In this embodiment, an excimer laser that irradiates a pulsed KrF excimer laser beam with a wavelength of 248 nm is used. The laser beam oscillated from the laser 10 is guided to a line beam forming unit 20 via a correction optical system for adjusting the optical axis (not shown). The laser 10 may be configured as a part of the laser processing apparatus 100, or may be configured as a separate device.

[0023] The line beam forming unit 20 includes an optical system including a lens array 24, a line beam forming optical system 25 including a cylindrical lens, and an angle switching mirror 26. The lens array 24 adjusts the intensity distribution of the incident laser light. The line beam forming optical system 25 shapes the beam luminous flux of the incident laser light into a line-shaped light LB.

[0024] The line beam forming unit 20 houses an optical system such as the line beam forming optical system 25 in its casing 20K, and the casing 20K is supported by a scanning mechanism 60. The scanning mechanism 60 is capable of moving the line beam forming unit 20 at a set speed along the main scanning direction (X direction), and is capable of moving the line-shaped light LB relatively to the mask M in the main scanning direction (X direction), which is the scanning direction.

[0025] Angle-switching mirror 26 provided in line beam forming unit 20 can shift the irradiation position of line-shaped light LB on mask M along the sub-scanning direction (Y direction) by switching its angle (position), that is, can switch the scanning area. Here, angle-switching mirror 26 is provided at a conjugate position between lens array 24 and line beam forming optical system 25.

[0026] The mask stage 40 supports the mask M and can move it in the main scanning direction (X direction) and the sub-scanning direction (Y direction), which is the scanning width direction of the line-shaped light LB, and can also rotate it. The mask stage movement mechanism 70 drives the mask stage 40 based on a signal output from a position detection encoder (not shown).

[0027] In the mask M, a light-shielding film (e.g., an Al film) that blocks the KrF excimer laser light is formed in a portion other than the mask pattern on a base material (e.g., quartz glass) that transmits the KrF excimer laser light. For example, a mask pattern for forming a through via as a processing pattern is formed on the mask M.

[0028] The projection optical system 30 is an imaging optical system having focal points on the surface of the mask M and the surface of the substrate W, and projects light (pattern light) that has passed through a mask pattern portion formed on the mask M onto the substrate W. Here, the projection optical system 30 is configured as a reduced projection optical system, and is set to a predetermined projection magnification (for example, 0.5 times).

[0029] The processing stage 50 is capable of fixing the substrate W by vacuum suction or the like, and of moving and rotating the substrate W in the main scanning direction (X direction) and sub-scanning direction (Y direction). The processing stage movement mechanism 80 drives the processing stage 50 based on a signal output from a position detection encoder (not shown).

[0030] The substrate W, which is a resin substrate, has a copper wiring layer formed on a base material such as epoxy resin, and an insulating layer formed thereon. By irradiating the substrate W with high-energy density excimer laser light from the excimer laser 10, ablation occurs on the substrate W, and a pattern (hereinafter referred to as a processing pattern) WA corresponding to the mask pattern formed on the mask M is formed. As the processing pattern WA, a through via, a non-through via, or a groove (trenches) for a wiring pattern can be formed.

[0031] As the scanning mechanism 60 moves the line beam forming unit 20 in the main scanning direction (X direction), a line-shaped light (hereinafter also referred to as a line-shaped beam) LB perpendicular to the main scanning direction (X direction) and parallel to the sub-scanning direction (Y direction) moves relative to the mask M (mask stage 40), the projection optical system 30, and the substrate W (processing stage 50). As a result, the mask M and the substrate W are scanned by the line-shaped beam LB. Here, a mask pattern corresponding to the pattern WA repeatedly formed on the substrate W is formed on the mask M.

[0032] The mask pattern formed on the mask M according to the processing area AR where the processing pattern WA is formed and the projection magnification of the projection optical system 30 has an area size exceeding the width of the line-shaped light LB. Then, the processing pattern WA is formed on the entire processing area AR by repeatedly performing scanning along the main scanning direction (X direction) while switching the irradiation position of the line-shaped light LB by the angle switching mirror 26.

[0033] Each time a processing pattern WA is formed in a processing area AR, the processing stage 50 moves stepwise in the main scanning direction (X direction) and sub-scanning direction (Y direction), and an ablation processing is performed over the entire substrate W. After the processing pattern is formed over the entire substrate W by ablation processing, a conductor such as copper is filled in. A mask pattern that draws a pattern over the entire substrate W may be formed on the mask M.

[0034] The controller 90 controls the angle switching mirror 26, the scanning mechanism 60, the mask stage moving mechanism 70, and the processing stage moving mechanism 80 of the line beam forming unit 20, and performs control in the ablation processing, i.e., positioning the mask M, positioning the substrate W, moving the line-shaped light LB in the main scanning direction (X direction), and switching the irradiation position along the sub-scanning direction (Y direction).

[0035] The projection optical system 30 is provided with a single-sided variable magnification optical unit 32 and an isotropic magnification correction optical unit 35. Here, the single-sided variable magnification optical unit 32 is disposed on the side of the projection optical system 30 closest to the mask M, and the isotropic magnification correction optical unit 35 is disposed on the side of the projection optical system 30 closest to the substrate W.

[0036] It is also possible to switch the locations of the single-variable magnification optical unit 32 and the isotropic magnification correction optical unit 35, or to place them in a lens group in the projection optical system 30 and at a position farther away from the mask M and the substrate W. Also, the single-variable magnification optical unit 32 and the isotropic magnification correction optical unit 35 may be provided in the optical path outside the projection optical system 30.

[0037] The single-sided variable magnification optical unit 32 is configured as an optical unit capable of changing and adjusting the projection magnification (imaging magnification) of the projection optical system 30 along one direction. Here, the single-sided variable magnification optical unit 32 is capable of changing the projection magnification along the Y axis in the sub-scanning direction.

[0038] On the other hand, the isotropic magnification correction optical unit 35 is configured as an optical unit capable of adjusting the projection magnification of the projection optical system 30 so as to maintain the scaling of the projected image. The isotropic magnification correction optical unit 35 can change the projection magnification isotropically with respect to the X-axis and Y-axis in the main scanning direction and sub-scanning direction. Here, the isotropic change means changing (scaling) the projected image at the same ratio regardless of the axial direction in the XY plane.

[0039] An alignment camera 29 that captures an image of an alignment mark provided on the mask M is installed in a casing 20K of the line beam forming unit 20. In addition, an alignment camera 38 that captures an image of an alignment mark provided on the substrate W is installed beside the processing stage 50. The alignment cameras 29, 38 capture images of alignment marks formed at predetermined positions (e.g., the four corners) of the mask M and the substrate W in accordance with the movement of the mask stage 40 and the processing stage 50 in the main scanning direction (X-axis) and sub-scanning direction (Y-axis), respectively.

[0040] The controller 90 detects the amount of positional deviation of the alignment marks from a reference position (such as a design position) based on image data obtained by imaging with the alignment cameras 29, 38, and measures the amount of expansion and contraction of the substrate W along the main scanning direction (X axis) and sub-scanning direction (Y axis). It is also possible to detect the amount of rotation (θ) of the substrate W relative to the Z axis that is perpendicular to the XY coordinate plane and parallel to the optical axis C of the projection optical system 30, and calculate the amount of expansion and contraction of the substrate W along the X and Y axis directions after taking the amount of rotation (θ) into account. Such methods for measuring (calculating) the amount of expansion and contraction of the substrate W are well known, and a detailed description thereof will be omitted.

[0041] The actuators 37 and 39 are capable of driving the single-sided variable magnification optical unit 32 and the isotropic magnification correction optical unit 35, respectively, along the optical axis C. The controller 90 controls the driving of the actuators 37 and 39 based on the measured amounts of expansion and contraction of the substrate W along the X-axis and Y-axis directions. Specifically, the positions of the single-sided variable magnification optical unit 32 and the isotropic magnification correction optical unit 35 are corrected along the optical axis C so that a projection image of a desired projection magnification is projected onto the substrate W.

[0042] Fig. 3 is a schematic perspective view of the single-sided variable magnification optical unit 32. Fig. 4 is a cross-sectional view of the single-sided variable magnification optical unit 32 taken along the YZ direction and along the XZ direction.

[0043] The single-sided variable magnification optical unit 32 is composed of a pair of lenses including a concave cylindrical lens 32A and a convex cylindrical lens 32B, the concave and convex portions of which are arranged to face each other. However, only the convex cylindrical lens 32B is shown in FIG. 3.

[0044] The opposite flat surfaces of the concave cylindrical lens 32A and the convex cylindrical lens 32B are parallel to a direction perpendicular to the optical axis C of the projection optical system 30. Here, the concave cylindrical lens 32A and the convex cylindrical lens 32B are each formed in a rectangular shape.

[0045] While the scanning mechanism 60 moves the line beam forming unit 20 in the main scanning direction (X direction), the line-shaped beam LB moves relative to the single-sided variable magnification optical unit 32 provided above the projection optical system 30. The concave cylindrical lens 32A and the convex cylindrical lens 32B are determined to have sizes such that the line-shaped beam LB passes through while changing its incidence surface 32I. The sizes of the concave cylindrical lens 32A and the convex cylindrical lens 32B are determined according to the width WB of the line-shaped beam LB, the energy density of the laser light source required for the ablation processing, the scanning speed, etc.

[0046] When the line beam LB moves in the main scanning direction, it moves while changing the passing position on the curved surface of the single-sided variable magnification optical unit 32. The light energy absorption load on the lens is dispersed, so the lifespan is extended. In addition, heat generated by light absorption is also dispersed, so the characteristic change due to thermal expansion of the lens can be suppressed.

[0047] The orientation of the single-sided variable magnification optical unit 32 is determined according to the direction of its generating line BM. Here, the single-sided variable magnification optical unit 32 is positioned so that the generating line BM of the concave cylindrical lens 32A and the convex cylindrical lens 32B is aligned with the scanning direction of the line-shaped beam BM. Therefore, the longitudinal direction of the line-shaped beam LB is aligned with the curved surface direction of the concave cylindrical lens 32A and the convex cylindrical lens 32B, i.e., the direction perpendicular to the generating line BM.

[0048] 4, the curvatures R1, R2 of the concave and convex portions of the concave cylindrical lens 32A and the convex cylindrical lens 32B are different. The curvatures R1, R2 are determined so that a gap GM occurs when the concave cylindrical lens 32A and the convex cylindrical lens 32B are closest to each other (contact state), and the entire curved surfaces of the concave and convex portions of the concave cylindrical lens 32A and the convex cylindrical lens 32B are not in close contact with each other.

[0049] This allows the stress between the lenses to be released and prevents damage when the lens heat distribution and thermal expansion coefficient change due to the movement of the line-shaped beam LB. Note that the curvatures R1 and R2 may be set to the same value so that the concave and convex portions of the concave cylindrical lens 32A and the convex cylindrical lens 32B are in full contact with each other.

[0050] The peripheries of the concave cylindrical lens 32A and the convex cylindrical lens 32B are held by a support frame (not shown). Here, one of the convex cylindrical lenses, the lens 32B, is slidable along the optical axis C, and the actuator 37 drives the convex cylindrical lens 32B through the support frame. For example, the actuator 37 can be configured by a mechanism combining a cam mechanism and a motor.

[0051] The controller 90 controls the driving of the convex cylindrical lens 32B based on the measured amount of expansion and contraction along the Y direction of the substrate W, and adjusts the distance T between the concave cylindrical lens 32A and the convex cylindrical lens 32B. As described above, the single-sided variable magnification optical unit 32 can correct the projection magnification in the Y axis direction as one axis, and the distance T is adjusted to reduce or enlarge the projection magnification.

[0052] For example, the projection magnification can be increased by making the distance T between the concave cylindrical lens 32A and the convex cylindrical lens 32B longer than the reference distance T0, and the projection magnification can be decreased by making it shorter than the reference distance T0.

[0053] The concave cylindrical lens 32A and the convex cylindrical lens 32B may be arranged in the opposite position to the optical axis C (the concave and convex directions may be reversed). Instead of the convex cylindrical lens 32B, the concave cylindrical lens 32A may be made movable. Alternatively, both the concave cylindrical lens 32A and the convex cylindrical lens 32B may be made movable along the optical axis C.

[0054] On the other hand, the isotropic magnification correction optical unit 35 (see FIG. 2) arranged near the substrate W is composed of one circular lens (e.g., a plano-convex lens or a biconvex lens) here. The actuator 39 moves the isotropic magnification correction optical unit 35 along the optical axis C, making it possible to isotropically change the projection magnification including the X-axis and Y-axis. The isotropic magnification correction optical unit 35 can also be composed of multiple lenses such as a focusing lens.

[0055] Fig. 5 is a diagram showing correction of the projection magnification of a projected image by the single-sided variable magnification optical unit 32. Fig. 6 is a diagram showing correction of the projection magnification of a projected image by the single-sided variable magnification optical unit 32 and the isotropic magnification correction optical unit 35.

[0056] As described above, the single-sided variable magnification optical unit 32 reduces or enlarges the projected image P along the Y-axis direction. In FIG. 5, the enlarged projected image is indicated by the symbol P'y, and the reduced projected image is indicated by the symbol P"y. Since the refractive power (refractive index) in the generatrix direction is constant during the line beam LB scan (see FIG. 3), the projected image can be enlarged or reduced uniformly at the same projection magnification for the entire width of the projected image P along the X-direction.

[0057] FIG. 6 shows a diagram in which the projected image is enlarged only in the X-axis direction by a combination of the single-sided variable magnification optical unit 32 and the isotropic magnification correction optical unit 35. After the projected image P is reduced at a predetermined reduction ratio (see symbol P"y), the reduced projected image P'y is isotropically enlarged in both the X-axis and Y-axis directions by the isotropic magnification correction optical unit 35, whereby the projected image P can be enlarged and formed as an image enlarged only in the X-axis direction (see symbol P'x).

[0058] It is possible to form a projected image at any projection magnification in the X-axis direction and the Y-axis direction by combining the single-variable magnification optical unit 32 and the isotropic magnification correction optical unit 35. Therefore, the controller 90 controls the positions of the single-variable magnification optical unit 32 and the isotropic magnification correction optical unit 35 based on the measured amount of expansion and contraction of the substrate X, and corrects the projection magnification according to the amount of expansion and contraction of the substrate W. This makes it possible to form a projected image on the substrate W according to an ideal (designed) projection magnification without expansion and contraction of the substrate W.

[0059] Next, a laser processing apparatus according to a second embodiment will be described with reference to Fig. 7. In the second embodiment, the arrangement direction of the single-sided variable magnification optical unit is different from that of the first embodiment.

[0060] 7 is a diagram showing a single-sided variable magnification optical unit of a laser processing apparatus according to the second embodiment. The single-sided variable magnification optical unit 132 is composed of a concave cylindrical lens (not shown here) and a convex cylindrical lens 132B.

[0061] The single-sided variable magnification optical unit 132 is disposed so that its generatrix BM is perpendicular to the scanning direction of the line-shaped beam LB, i.e., along the longitudinal direction of the line-shaped beam LB. Therefore, the single-sided variable magnification optical unit 132 reduces or enlarges the projected image only along the X-axis direction. As in the first embodiment, the convex cylindrical lens 132B is movable along the optical axis C, and the projected image is reduced or enlarged by changing the distance between the convex cylindrical lens 132B and the concave cylindrical lens.

[0062] By disposing the single-sided variable magnification optical unit 132 in this way, the thickness of the cylindrical lens in the longitudinal direction of the line-shaped beam LB becomes uniform. That is, the amount of refraction (refractive index) becomes constant. Therefore, while the line-shaped beam LB is moving the single-sided variable magnification optical unit 35 relatively, by varying the position of the convex cylindrical lens 132B, it is possible to finely adjust the projection magnification along the X-axis direction.

[0063] For example, by forming a large number of alignment marks in a processing area AR defined for the mask M and the substrate W, it is possible to set the projection magnification and finely adjust the reduction or enlargement of the projected image in accordance with the scanning position within the area. Also, as in the first embodiment, by combining with the isotropic magnification correction optical unit 35, it is possible to enlarge or reduce the projected image at any projection magnification along the X-axis and Y-axis.

[0064] As described above, the laser processing apparatus 100 shown in the first and second embodiments includes the single-sided variable magnification optical unit 32 (132) composed of a pair of lenses in which a convex cylindrical lens and a concave cylindrical lens are arranged with their concave and convex surfaces facing each other. The single-sided variable magnification optical unit 32 (132) is arranged so that its generating line BM is aligned along the scanning direction of the line beam LB (along the direction perpendicular to the scanning direction). By adjusting the distance T along the optical axis C of the convex cylindrical lens and the concave cylindrical lens, the projection magnification of the projection optical system 30 can be corrected along one direction, the Y axis (X axis), and the projected image can be reduced or enlarged.

[0065] Furthermore, the laser processing apparatus 100 is equipped with an isotropic magnification correction optical unit 35, which, in combination with the single-sided variable magnification optical unit 32 (132), makes it possible to reduce or enlarge the projected image only along the Y-axis or X-axis direction, and furthermore, to reduce or enlarge the projected image at any projection magnification along each of the X-axis and Y-axis.

[0066] A mechanism may be used in which the single-magnification variable optical unit 32 shown in the first embodiment and the single-magnification variable optical unit 132 shown in the second embodiment are prepared, one of the single-magnification variable optical units is arranged along the optical axis C, and the other is arranged in a retracted position. Also, a mechanism may be used in which the single-magnification variable optical unit 32 can be rotated about the optical axis C, and the single-magnification variable optical unit 32 in the arrangement state shown in the first embodiment can be changed to the position shown in the second embodiment by rotating it 90 degrees depending on the amount of expansion and contraction and the direction of expansion and contraction of the board.

[0067] In the first and second embodiments, the single-sided variable magnification optical unit 32 (132) is arranged so that its generating line BM is aligned parallel or perpendicular to the scanning direction of the line-shaped beam LB, but it is possible to arrange the single-sided variable magnification optical unit 32 (132) so that the generating line BM is inclined, i.e., oblique, with respect to the direction parallel or perpendicular to the scanning direction of the line-shaped beam LB.

[0068] For example, it is possible to configure the system so that the direction of the generating line M is changed during the scanning period of the line-shaped beam LB. Scanning is started with the generating line BM and the line-shaped beam LB parallel or perpendicular to each other, and the actuator 37 can rotate the single-side magnification variable unit 32 (132) by a predetermined angle around the optical axis C at a predetermined timing. Furthermore, it is possible to configure the generating line BM to return to a state in which it faces the scanning direction of the line-shaped beam LB or a state in which it faces perpendicularly, and adjust the direction of the generating line BM in accordance with the amount of deformation of the substrate, particularly the amount of deformation of the substrate in the area to be scanned by the line-shaped beam, by controlling the actuator 37 with the controller 90.

[0069] Alternatively, the single-sided variable magnification optical unit 32 (132) may be arranged in advance so that the generating line BM is aligned along a direction inclined at a predetermined angle with respect to the scanning direction of the line-shaped beam LB or a direction perpendicular to the line-shaped beam LB, and then the line-shaped beam LB may be scanned. Then, during the scanning period, scanning control may be performed so that the generating line BM is changed to a state in which it faces the scanning direction of the line-shaped beam LB or a state in which it faces a perpendicular direction, and then returned to the oblique direction again at a predetermined timing.

[0070] As described above, during laser processing, the line-shaped beam LB passes through the single-sided variable magnification optical unit 32 (132) while moving its position on the optical surface. By adjusting the direction of the generatrix BM of the single-sided variable magnification optical unit 32 (132), the direction of magnification can be arbitrarily determined based on the scanning direction or the perpendicular direction of the line-shaped beam LB. This makes it possible to correct the pattern accordingly even if a complex deformation occurs in the substrate. Note that the configurations shown in the first and second embodiments also make it possible to correct the pattern according to the deformation direction and amount of the substrate. [Explanation of symbols]

[0071] 100 Laser processing equipment 20 Line beam forming section 25 Line beam forming optics 30 Projection optical system 32 Single variable magnification optical unit 32A Concave cylindrical lens 32B Convex cylindrical lens 35 Isotropic magnification correction optical unit

Claims

1. a line beam forming optical system that shapes the laser beam into a line; a projection optical system that projects the line-shaped beam that has passed through the mask onto a workpiece; a single-sided variable magnification optical unit in which a convex cylindrical lens and a concave cylindrical lens are disposed opposite each other; a scanning mechanism for scanning the line-shaped beam over the mask, the single-sided variable magnification optical unit, and the projection optical system, A laser processing apparatus capable of changing the projection magnification in one direction of the projection optical system by changing the distance between the convex cylindrical lens and the concave cylindrical lens along the optical axis of the projection optical system.

2. 2. The laser processing apparatus according to claim 1, further comprising an isotropic magnification correction optical unit that is configured to be capable of isotropically correcting the projection magnification of the projection optical system and that is composed of one or a plurality of lenses.

3. 3. The laser processing apparatus according to claim 2, wherein the one-sided variable magnification optical unit is disposed on the mask side of the isotropic magnification correction optical unit along the optical axis of the projection optical system.

4. 2. The laser processing device according to claim 1, wherein the distance between the convex cylindrical lens and the concave cylindrical lens is variable during a period in which the line-shaped beam is scanned across the single-side variable magnification optical unit.

5. 2. The laser processing apparatus according to claim 1, wherein a curvature of the convex cylindrical lens is different from a curvature of the concave cylindrical lens.

6. 6. The laser processing apparatus according to claim 1, wherein the single-sided variable magnification optical unit is disposed so that its generating line is aligned with the scanning direction of the line-shaped beam.

7. 6. The laser processing apparatus according to claim 1, wherein the single-sided variable magnification optical unit is disposed so that its generating line is aligned along a direction perpendicular to the scanning direction of the line-shaped beam.

8. 6. The laser processing apparatus according to claim 1, wherein the single-sided variable magnification optical unit is disposed so that its generating line is parallel to or inclined relative to the scanning direction of the line-shaped beam.

9. 6. The laser processing apparatus according to claim 1, further comprising an actuator capable of rotating the single-sided variable magnification optical unit about an optical axis.

10. A projection optical system of a laser processing apparatus that projects a line-shaped beam transmitted through a mask onto a workpiece while scanning the line-shaped beam, a single-sided variable magnification optical unit in which a convex cylindrical lens and a concave cylindrical lens are arranged opposite each other, the single-sided variable magnification optical unit is configured such that, when scanning the line-shaped beam, the line-shaped beam passes through the single-sided variable magnification optical unit while changing an incident surface position of the single-sided variable magnification optical unit in a beam width direction; A projection optical system for a laser processing apparatus, characterized in that the projection magnification in one direction can be changed by changing the distance between said convex cylindrical lens and said concave cylindrical lens along the optical axis.

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