Laser processing apparatus and projection optical system for laser processing apparatus

Abstract

The invention provides a laser processing apparatus and a projection optical system of the laser processing apparatus. In a laser processing apparatus that scans a linear beam, a projection image is appropriately corrected with respect to expansion and contraction of a workpiece such as a substrate. A laser processing device (100) is provided with a unidirectional variable magnification optical unit (32) comprising a group of lenses in which a convex cylindrical lens and a concave cylindrical lens are disposed so that the concave and convex surfaces face each other, and the unidirectional variable magnification optical unit (32) is disposed so that the generatrix (BM) of the unidirectional variable magnification optical unit (32) follows the scanning direction of a linear beam (LB). The projection magnification of the projection optical system (30) can be corrected along the Y-axis in one direction by adjusting the distance (T) between the convex cylindrical lens and the concave cylindrical lens along the optical axis (C), and the projection image can be reduced or enlarged.

Description

Technical Field

[0001] The present invention relates to a laser processing device for processing a workpiece such as a substrate using a high-energy-density laser, and more particularly to correction of a projection image that is deformed with respect to the substrate. Background Art

[0002] For printed wiring boards, laminated PKG boards, etc., high-precision pattern formation is required as patterns become finer and high-density mounting is achieved. As a processing method for forming tiny vias and grooves (grooves), ablation processing using a laser processing device is known (see Patent Documents 1 and 2).

[0003] Among them, high-energy-density lasers such as excimer lasers are shaped into linear beams, which are moved relative to a fixed mask (reticle) and projection lens to project patterned light onto a substrate, etc. The surface of the material is instantly removed according to the mask pattern, thereby forming vias and grooves on the substrate.

[0004] In a laser processing device, a high-density energy laser is irradiated, so during the processing process, a substrate or other workpiece undergoes thermal deformation and expansion and contraction. In order to cope with such deformation of the substrate or the like, for example, an autofocus unit is provided in a laser processing device of a scanning type that irradiates a linear beam while scanning a mask and a substrate. The autofocus function changes the focal length according to the expansion and contraction amount, and the projection magnification of the projection lens is adjusted (see Patent Document 3).

[0005] Patent Document 1: International Publication No. 2020 / 003421

[0006] Patent Document 2: Japanese Patent Application Publication No. 2021-49560

[0007] Patent Document 3: Japanese Patent Application Publication No. 2008-221299

[0008] In a laser processing apparatus that scans a linear beam, a scanning direction for each processing area is set from the viewpoints of the size of the processing area of ​​the substrate, optical characteristics such as the reduction ratio of the projection optical system, and productivity improvement.

[0009] On the other hand, due to the influence of the laser processing technology and its forward and backward stroke, the expansion and contraction direction and amount of the substrate are various and are not related to the scanning direction of the linear beam. In addition, the expansion and contraction direction and amount of the substrate are not necessarily constant within the entire range of the substrate, and sometimes vary depending on the area of ​​the substrate. Summary of the invention

[0010] Therefore, in a laser processing apparatus that scans a linear beam, it is required to appropriately correct a projection image with respect to expansion and contraction of a workpiece such as a substrate.

[0011] A laser processing device as one embodiment of the present invention has: a beam forming optical system that shapes the laser into a linear shape; a projection optical system that projects the linear beam that has passed through the mask onto the workpiece; and an optical unit that is obtained by arranging a convex cylindrical lens and a concave cylindrical lens opposite to each other. The optical unit is configured as an optical unit (hereinafter referred to as a one-way variable magnification optical unit) that can change and adjust the projection magnification (imaging magnification) of the projection optical system 30 along one direction. In addition, the laser processing device has a scanning mechanism that scans the linear beam relative to the mask, the one-way variable magnification optical unit, and the projection optical system. In the one-way variable magnification optical unit, the linear beam passes through while changing its position, and the projection magnification of the projection optical system in one direction can be changed by changing the distance interval between the convex cylindrical lens and the concave cylindrical lens along the optical axis of the projection optical system. The one-way variable magnification optical unit can be set in the projection optical system or on the optical path outside the projection optical system.

[0012] The one-way variable magnification optical unit is configured such that when the linear light beam is scanned, the linear light beam passes through the one-way variable magnification optical unit while changing the incident surface position of the one-way variable magnification optical unit in the beam width direction. Therefore, the configuration of the one-way variable magnification optical unit taking into account the scanning direction of the linear light beam enables pattern correction corresponding to the deformation direction and deformation amount of the substrate.

[0013] Regarding the one-way variable magnification optical unit, various structures can be applied, and the curvature of the convex cylindrical lens and the curvature of the concave cylindrical lens can be set arbitrarily. For example, the one-way variable magnification optical unit can be constructed so that the curvatures of the convex cylindrical lens and the concave cylindrical lens are different from each other. In addition, the laser processing device can have an actuator that can move the lens in the optical axis direction, and the projection magnification can be changed by driving the actuator.

[0014] Regarding the configuration structure of the above-mentioned one-way variable magnification optical unit in which the linear light beam moves on the optical surface during scanning, various configuration structures can be applied according to the deformation direction, deformation amount, etc. of the substrate. For example, the one-way variable magnification optical unit can be configured so that its busbar is along the scanning direction of the linear light beam. Furthermore, the one-way variable magnification optical unit can be configured so that its busbar is along a direction perpendicular to the scanning direction of the linear light beam. Furthermore, the one-way variable magnification optical unit can also be configured so that its busbar is along a direction inclined relative to a direction parallel to the scanning direction of the linear light beam or a direction perpendicular to the scanning direction of the linear light beam. The one-way variable magnification optical unit can be selectively configured so that the busbar is pre-oriented in the above-mentioned direction.

[0015] On the other hand, the laser processing device may have an actuator capable of rotating the one-way variable magnification optical unit around the optical axis. The above-mentioned actuator may be used together, or a dedicated actuator may be provided separately. Before scanning the linear beam, the busbar may be directed in the above-mentioned direction to scan the linear beam. Alternatively, it may be configured such that during scanning, the direction of the busbar is changed at a predetermined time, for example, according to the deformation direction and deformation amount of the substrate.

[0016] Furthermore, the laser processing device may have an optical unit composed of one or more lenses (hereinafter referred to as an isotropic magnification correction optical unit) capable of isotropically correcting the projection magnification of the projection optical system. The isotropic magnification correction optical unit is configured as an optical unit capable of adjusting the projection magnification in a manner that maintains the scaling ratio of the projection image. The projection 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 one-way variable magnification optical unit can be arranged at a position closer to the mask side than the isotropic magnification correction optical unit along the optical axis of the projection optical system.

[0017] Furthermore, the laser processing device may be configured to change the distance between the convex cylindrical lens and the concave cylindrical lens by driving the actuator while the linear beam is being scanned with respect to the one-way variable power optical unit.

[0018] As another embodiment of the present invention, the projection optical system of a laser processing device projects a linear light beam that has passed through a mask onto a workpiece while scanning, wherein the projection optical system of the laser processing device has a one-way variable magnification optical unit, which is obtained by arranging a convex cylindrical lens and a concave cylindrical lens opposite to each other. The one-way variable magnification optical unit is configured such that when the linear light beam is scanned, the linear light beam passes through the one-way variable magnification optical unit while changing the position of the incident surface of the one-way variable magnification optical unit in the direction of the beam width. In addition, the laser processing device can change the projection magnification in one direction by changing the distance interval between the convex cylindrical lens and the concave cylindrical lens along the optical axis.

[0019] According to the present invention, in a laser processing apparatus that scans a linear beam, a projection image can be appropriately corrected with respect to expansion and contraction of a workpiece such as a substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic structural diagram of a laser processing device as a first embodiment.

[0021] Figure 2 This is a schematic block diagram of a laser processing device.

[0022] Figure 3 It is a schematic perspective view of the one-way variable power optical unit 32 .

[0023] Figure 4 1 and 2 are a cross-sectional view of the one-way variable power optical unit 32 along the YZ direction and a cross-sectional view along the XZ direction.

[0024] Figure 5 1 is a diagram showing correction of the projection magnification of a projection image performed by the one-way variable power optical unit 32 .

[0025] Figure 6 The diagram shows correction of the projection magnification of a projection image by the unidirectional variable magnification optical unit 32 and the isotropic magnification correction optical unit 35 .

[0026] Figure 7 This is a diagram showing a one-way variable power optical unit of a laser processing device as a second embodiment.

[0027] Description of symbols

[0028] 100: laser processing device; 20: beam forming unit; 25: beam forming optical system; 30: projection optical system; 32: one-way variable magnification optical unit; 32A: concave cylindrical lens; 32B: convex cylindrical lens; 35: isotropic magnification correction optical unit. DETAILED DESCRIPTION

[0029] Hereinafter, the laser processing apparatus according to the present embodiment will be described with reference to the drawings.

[0030] Figure 1 It is a schematic structural diagram of a laser processing device as a first embodiment. Figure 2 This is a schematic block diagram of a laser processing device.

[0031] The laser processing device 100 is a processing device capable of forming a pattern on a substrate W by ablation processing, and includes a beam forming unit 20, a projection optical system 30, a mask stage 40, and a processing stage 50. The beam forming unit 20, the mask stage 40, and the processing stage 50 are equipped on a device body (not shown) and can move relative to the device 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 composed of a resin substrate such as a printed substrate.

[0032] The laser 10 disposed near the device body oscillates a high energy density laser. Here, an excimer laser of a KrF excimer laser having a pulse irradiation wavelength of 248 nm is applied. The laser oscillated from the laser 10 is guided to the 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 device 100, or may be configured as an independent device.

[0033] The beam forming unit 20 includes an optical system such as a lens array 24, a beam forming optical system 25, and an angle switching mirror 26. The beam forming optical system 25 includes a cylindrical lens, etc. The lens array 24 adjusts the intensity distribution of the incident laser light. The beam forming optical system 25 shapes the incident laser light beam into a linear light LB.

[0034] The beam forming unit 20 accommodates an optical system such as a beam forming optical system 25 in its housing 20K, and the housing 20K is supported by a scanning mechanism 60. The scanning mechanism 60 can move the beam forming unit 20 along the main scanning direction (X direction) at a set speed, and move the linear light LB relative to the mask M in the main scanning direction (X direction) as the scanning direction.

[0035] The angle switching mirror 26 provided in the line beam forming unit 20 can shift the irradiation position of the linear light LB on the mask M along the sub-scanning direction (Y direction) by switching its angle (position), that is, it can switch the scanning area. Here, the angle switching mirror 26 is provided at a conjugate position between the lens array 24 and the line beam forming optical system 25.

[0036] The mask stage 40 supports the mask M and can move the mask M in the main scanning direction (X direction) and the sub-scanning direction (Y direction) which is the scanning width direction of the linear light LB, and can rotate the mask M. The mask stage moving mechanism 70 drives the mask stage 40 based on a signal output from a position detection encoder (not shown).

[0037] A light shielding film (e.g., Al film) is formed on a portion other than the mask pattern of the mask M. The light shielding film (e.g., Al film) shields the KrF excimer laser from the base material (e.g., quartz glass) that transmits the KrF excimer laser. For example, a mask pattern forming a through hole is formed on the mask M as a processing pattern.

[0038] 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 the mask pattern portion formed by 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 (e.g., 0.5 times).

[0039] The processing stage 50 can fix the substrate W by vacuum adsorption, etc., and move the substrate W in the main scanning direction (X direction) and the sub-scanning direction (Y direction), and rotate the substrate W. The processing stage moving mechanism 80 drives the processing stage 50 based on a signal output from a position detection encoder (not shown).

[0040] A copper wiring layer is formed on a base material such as epoxy resin of a substrate W as a resin substrate, and an insulating layer is formed on the copper wiring layer. The substrate W is ablated by irradiating high-energy-density excimer laser light from an excimer laser 10 to form a pattern (hereinafter referred to as a processing pattern) WA corresponding to the mask pattern formed by the mask M. As the processing pattern WA, a through via, a non-through via, or a groove (groove) for a wiring pattern can be formed.

[0041] As the scanning mechanism 60 moves the line beam forming unit 20 in the main scanning direction (X direction), the linear light (hereinafter also referred to as the linear light 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 linear light beam LB. Here, the mask M is formed with a mask pattern corresponding to the pattern WA repeatedly formed on the substrate W.

[0042] The mask pattern formed on the mask M has an area size that exceeds the width of the linear light LB according to the processing area AR where the processing pattern WA is formed and the projection magnification of the projection optical system 30. In addition, while switching the irradiation position of the linear light LB by the angle switching mirror 26, scanning along the main scanning direction (X direction) is repeated, thereby forming a processing pattern WA for the entire processing area AR.

[0043] Whenever the processing pattern WA is formed on the processing area AR, the processing stage 50 moves stepwise along the main scanning direction (X direction) and the sub-scanning direction (Y direction) to perform ablation processing on the entire substrate W. After the processing pattern is formed on the entire substrate W by ablation processing, a conductor such as copper is filled. In addition, a mask pattern that depicts a pattern that extends over the entire substrate W may be formed on the mask M.

[0044] The controller 90 controls the angle switching mirror 26, the scanning mechanism 60, the mask carrier moving mechanism 70, and the processing carrier moving mechanism 80 of the beam forming unit 20, and performs control of the ablation processing, namely, positioning of the mask M, positioning of the substrate W, movement of the linear light LB in the main scanning direction (X direction), and switching of the irradiation position along the sub-scanning direction (Y direction).

[0045] The projection optical system 30 is provided with a one-way variable magnification optical unit 32 and an isotropic magnification correction optical unit 35. Here, the one-way variable magnification optical unit 32 is arranged on the side of the projection optical system 30 closest to the mask M, and the isotropic magnification correction optical unit 35 is arranged on the side of the projection optical system 30 closest to the substrate W.

[0046] In addition, the configuration of the one-way variable magnification optical unit 32 and the isotropic magnification correction optical unit 35 may be exchanged, and the lens group arranged in the projection optical system 30 may be arranged at a position farther from the mask M and the substrate W. Furthermore, the one-way 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.

[0047] The one-way 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 in one direction. Here, the one-way variable magnification optical unit 32 can change the projection magnification along the Y axis of the sub-scanning direction.

[0048] On the other hand, the isotropic magnification correction optical unit 35 is configured as an optical unit that can adjust the projection magnification of the projection optical system 30 in a manner that maintains the scaling ratio of the projection image. The isotropic magnification correction optical unit 35 can isotropically change the projection magnification with respect to the X-axis and the Y-axis in the main scanning direction and the sub-scanning direction. The isotropic change here means that the projection image is changed (scaled) at an equal ratio in the XY plane regardless of the axial direction.

[0049] An alignment camera 29 for photographing the alignment mark provided on the mask M is provided in the housing 20K of the harness forming unit 20. Also, an alignment camera 38 for photographing the alignment mark provided on the substrate W is provided near the processing stage 50. As the mask stage 40 and the processing stage 50 move in the main scanning direction (X axis) and the sub-scanning direction (Y axis), the alignment cameras 29 and 38 photograph the alignment marks formed at predetermined positions (e.g., four corners) of the mask M and the substrate W, respectively.

[0050] The controller 90 detects the positional deviation of the alignment mark relative to the reference position (design position, etc.) based on the image data obtained by the alignment cameras 29 and 38, and measures the expansion and contraction amount of the substrate W along the main scanning direction (X axis) and the sub-scanning direction (Y axis). In addition, the rotation amount (θ) of the substrate W relative to the Z axis which is perpendicular to the XY coordinate plane and parallel to the optical axis C of the projection optical system 30 can also be detected, and the expansion and contraction amount of the substrate W along the X axis and the Y axis direction can be obtained based on the rotation amount (θ). Such a method of measuring (calculating) the expansion and contraction amount of the substrate W is well known, and a detailed description thereof is omitted.

[0051] The actuator 37 and the actuator 39 can respectively drive the one-way zoom optical unit 32 and the isotropic magnification correction optical unit 35 along the optical axis C. The controller 90 drives and controls the actuator 37 and the actuator 39 according to the measured expansion and contraction amounts of the substrate W along the X-axis and the Y-axis directions. Specifically, the positions of the zoom 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 can be projected onto the substrate W.

[0052] Figure 3 It is a schematic perspective view of the one-way variable power optical unit 32 . Figure 4 1 and 2 are a cross-sectional view of the one-way variable power optical unit 32 along the YZ direction and a cross-sectional view along the XZ direction.

[0053] The one-way variable magnification optical unit 32 is composed of a group of lenses including a concave cylindrical lens 32A and a convex cylindrical lens 32B, and the concave and convex portions are arranged to face each other. Figure 3 In the figure, only the convex cylindrical lens 32B is shown.

[0054] The opposite side planes of the concave cylindrical lens 32A and the convex cylindrical lens 32B are parallel to the 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 square shape.

[0055] While the scanning mechanism 60 moves the line beam forming unit 20 in the main scanning direction (X direction), the linear light beam LB moves relative to the one-way variable magnification optical unit 32 disposed above the projection optical system 30. The concave cylindrical lens 32A and the convex cylindrical lens 32B are set to have such a size that the linear light beam LB can pass through while changing on its incident surface 32I. In addition, the size of the concave cylindrical lens 32A and the convex cylindrical lens 32B is set according to the width WB of the linear light beam LB, the energy density of the laser light source required for ablation processing, the scanning speed, etc.

[0056] When the linear light beam LB moves in the main scanning direction, it moves while changing the passing position on the curved surface of the one-way variable magnification optical unit 32. Since the light energy absorption load toward the lens is dispersed, the life is prolonged. In addition, the heat caused by light absorption is also dispersed, so the characteristic change caused by the thermal expansion of the lens can be suppressed.

[0057] The one-way variable magnification optical unit 32 is configured in accordance with the direction of its busbar BM. Here, the one-way variable magnification optical unit 32 is positioned so that the busbar BM of the concave cylindrical lens 32A and the convex cylindrical lens 32B is along the scanning direction of the linear light beam BM. Therefore, the length direction of the linear light beam LB is along the curved surface direction of the concave cylindrical lens 32A and the convex cylindrical lens 32B, that is, the direction perpendicular to the busbar BM.

[0058] like Figure 4 As shown, the curvatures R1 and R2 of the concave and convex parts of the concave cylindrical lens 32A and the convex cylindrical lens 32B are different. The curvatures R1 and R2 are set so that a gap GM is generated when the concave cylindrical lens 32A and the convex cylindrical lens 32B are in the closest state (contact state), and the curved surfaces of the concave and convex parts of the concave cylindrical lens 32A and the convex cylindrical lens 32B are not in close contact as a whole.

[0059] Thus, when the thermal distribution and thermal expansion coefficient of the lens change due to the movement of the linear beam LB, the stress between the lenses can be released to prevent damage. In addition, the curvatures R1 and R2 can be set to the same value so that the concave and convex parts of the concave cylindrical lens 32A and the convex cylindrical lens 32B are closely fitted over the entire surface.

[0060] The peripheries of the concave cylindrical lens 32A and the convex cylindrical lens 32B are held by a support frame (not shown). Here, the convex cylindrical lens 32B on one side can slide along the optical axis C, and the actuator 37 drives the convex cylindrical lens 32B via the support frame. For example, the actuator 37 can be constituted by a mechanism combining a cam mechanism and a motor.

[0061] The controller 90 drives and controls the convex cylindrical lens 32B according to the measured expansion and contraction amount of the substrate W along the Y direction, and adjusts the distance T between the concave cylindrical lens 32A and the convex cylindrical lens 32B. As described above, the one-way variable magnification optical unit 32 can correct the projection magnification in the Y-axis direction as the 1 axis, and adjusts the distance T in order to reduce or increase the projection magnification.

[0062] 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 the distance T shorter than the reference distance T0.

[0063] In addition, regarding the configuration of the concave cylindrical lens 32A and the convex cylindrical lens 32B, the positional relationship along the optical axis C may be reversed (the concave and convex directions are opposite). The concave cylindrical lens 32A may be moved instead of the convex cylindrical lens 32B. Alternatively, both the concave cylindrical lens 32A and the convex cylindrical lens 32B may be moved along the optical axis C.

[0064] On the other hand, here, the isotropic magnification correction optical unit 35 (see Figure 2 ) is composed of a circular lens (for example, a plano-convex lens or a biconvex lens). By moving the isotropic magnification correction optical unit 35 along the optical axis C by the actuator 39, the projection magnification can be isotropically changed in each direction including the X-axis and the Y-axis. In addition, the isotropic magnification correction optical unit 35 can also be composed of a plurality of lenses such as a focusing lens.

[0065] Figure 5 2 is a diagram showing correction of the projection magnification of the projection image performed by the one-way variable power optical unit 32 . Figure 6 1 and 2 are diagrams showing correction of the projection magnification of a projection image by the unidirectional variable magnification optical unit 32 and the isotropic magnification correction optical unit 35 .

[0066] As described above, the one-way variable magnification optical unit 32 reduces or enlarges the projection image P along the Y-axis direction. Figure 5 In the figure, the enlarged projection image is represented by the symbol P'y, and the reduced projection image is represented by the symbol P"y. During the scanning of the linear beam LB, the optical power (refractive index) in the generatrix direction is constant (refer to Figure 3 ), so the projection image P can be enlarged or reduced at the same projection magnification for the entire width along the X direction.

[0067] exist Figure 6 , a diagram showing a projection image enlarged only in the X-axis direction by a combination of a one-way variable magnification optical unit 32 and an isotropic magnification correction optical unit 35 is shown. After the projection image P is reduced by a predetermined reduction ratio (refer to the reference symbol P"y), the reduced projection image P"y is isotropically enlarged in each direction including the X-axis and the Y-axis by the isotropic magnification correction optical unit 35, thereby enabling the projection image P to be enlarged to form an image enlarged only in the X-axis direction (refer to the reference symbol P'x).

[0068] In addition, a projection image can be formed at an arbitrary projection magnification in the X-axis direction and the Y-axis direction by combining the one-way variable magnification optical unit 32 and the isotropic magnification correction optical unit 35. Therefore, the controller 90 controls the position of the one-way variable magnification optical unit 32 and the isotropic magnification correction optical unit 35 according to the measured expansion and contraction amount of the substrate X, and corrects the projection magnification according to the expansion and contraction amount of the substrate W. Thus, a projection image can be formed on the substrate W in accordance with an ideal (designed) projection magnification in which the substrate W does not expand and contract.

[0069] Next, use Figure 7 A laser processing apparatus according to a second embodiment will be described. In the second embodiment, the arrangement direction of the one-way variable power optical unit is different from that of the first embodiment.

[0070] Figure 7 1 is a diagram showing a one-way variable power optical unit of a laser processing device as a second embodiment. The one-way variable power optical unit 132 is composed of a concave cylindrical lens (not shown here) and a convex cylindrical lens 132B.

[0071] The one-way variable magnification optical unit 132 is configured such that its busbar BM is along a direction perpendicular to the scanning direction of the linear light beam LB, i.e., the length direction of the linear light beam LB. Therefore, the one-way variable magnification optical unit 132 reduces or enlarges the projection image only along the X-axis direction. As in the first embodiment, the convex cylindrical lens 132B can move along the optical axis C, and reduces or enlarges the projection image by changing the distance interval with the concave cylindrical lens.

[0072] By configuring the one-way zoom optical unit 132 in this way, the thickness of the cylindrical lens in the length direction of the linear light beam LB becomes uniform. That is, the refractive amount (refractive index) is constant. Therefore, during the period when the linear light beam LB moves relative to the one-way zoom optical unit 35, the projection magnification along the X-axis direction can be finely adjusted by changing the position of the convex cylindrical lens 132B.

[0073] For example, by forming a plurality of alignment marks on the processing area AR specified by the mask M on the substrate W, the projection magnification can be finely set and the reduction or enlargement of the projection image can be finely adjusted in accordance with the scanning position in the area. In addition, as in the first embodiment, by combining with the isotropic magnification correction optical unit 35, the projection image can be enlarged or reduced at an arbitrary projection magnification along the X-axis and the Y-axis.

[0074] As described above, the laser processing device 100 shown in the first and second embodiments has a one-way variable magnification optical unit 32 (132), which is composed of a group of lenses obtained by arranging a convex cylindrical lens and a concave cylindrical lens in a manner that the concave and convex surfaces are opposite to each other. Moreover, the one-way variable magnification optical unit 32 (132) is configured so that its master line BM is along the scanning direction of the linear light beam LB (along the direction perpendicular to the scanning direction). By adjusting the distance interval T between the convex cylindrical lens and the concave cylindrical lens along the optical axis C, the projection magnification of the projection optical system 30 can be corrected along the Y axis (X axis) in one direction, and the projection image can be reduced or enlarged.

[0075] In addition, the laser processing device 100 has an isotropic magnification correction optical unit 35, which, by combining with the one-way variable magnification optical unit 32 (132), can reduce or enlarge the projection image only along the Y-axis or X-axis direction, and can reduce or enlarge the projection image at any projection magnification along the X-axis and Y-axis respectively.

[0076] The following mechanism may also be used: prepare the one-way variable magnification optical unit 32 shown in the first embodiment and the one-way variable magnification optical unit 132 shown in the second embodiment, configure one of the one-way variable magnification optical units along the optical axis C, and configure the other in a retracted position. Furthermore, a mechanism may be used to rotate the one-way variable magnification optical unit 32 about the optical axis C, and the one-way variable magnification optical unit 32 in the configuration state shown in the first embodiment may be rotated 90 degrees according to the expansion and contraction amount and expansion and contraction direction of the substrate, thereby changing the configuration to the position shown in the second embodiment.

[0077] In the first and second embodiments, the one-way variable magnification optical unit 32 (132) is configured so that its bus line BM is along a direction parallel to or perpendicular to the scanning direction of the linear light beam LB, but the one-way variable magnification optical unit 32 (132) can also be configured so that the bus line BM is inclined relative to the direction parallel to or perpendicular to the scanning direction of the linear light beam LB, that is, in an inclined direction.

[0078] For example, the structure may be such that the direction of the busbar M is changed during the scanning of the linear light beam LB. The scanning may be started with the busbar BM being parallel to or perpendicular to the linear light beam LB, and the one-way variable magnification optical unit 32 (132) is rotated by a predetermined angle around the optical axis C at a predetermined timing by means of the actuator 37. Furthermore, the structure may be such that the busbar BM can be returned to a state in which the busbar BM is directed in the scanning direction of the linear light beam LB or in a perpendicular direction, and the direction of the busbar BM can be adjusted to match the deformation amount of the substrate, especially the deformation amount of the substrate in the area to be scanned by the linear light beam, by controlling the actuator 37 by the controller 90.

[0079] Alternatively, the one-way variable magnification optical unit 32 (132) may be configured in advance so that the busbar BM is tilted at a predetermined angle relative to the scanning direction or the vertical direction of the linear light beam LB, and then the linear light beam LB is scanned. Furthermore, during scanning, scanning control may be performed at a predetermined timing so that the busbar BM is changed to a state in which it is oriented toward the scanning direction of the linear light beam LB or toward the vertical direction, and then returned to the tilted direction.

[0080] As described above, the structure is such that, during laser processing, the linear light beam LB passes through the one-way variable magnification optical unit 32 (132) while its position moves on the optical surface. Moreover, by adjusting the direction of the busbar BM of the one-way variable magnification optical unit 32 (132), the magnification direction can be arbitrarily set based on the scanning direction or the vertical direction of the linear light beam LB. Thus, even if complex substrate deformation occurs, the pattern correction corresponding to it can be performed. In addition, in the structures shown in the first and second embodiments, the pattern correction that matches the deformation direction and deformation amount of the substrate can also be performed.

Claims

1. A laser processing device, characterized in that: The laser processing device comprises: A beam-forming optical system that shapes the laser light into a line shape; A projection optical system that projects a linear light beam that has passed through the mask onto a workpiece; A one-way variable magnification optical unit, which is obtained by arranging a convex cylindrical lens and a concave cylindrical lens opposite to each other; and a scanning mechanism for scanning a linear light beam relative to the mask, the one-way variable magnification optical unit, and the projection optical system, 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.

2. The laser processing device according to claim 1, characterized in that: The laser processing device further includes an isotropic magnification correction optical unit composed of one or more lenses, and the isotropic magnification correction optical unit can isotropically correct the projection magnification of the projection optical system.

3. The laser processing device according to claim 2, characterized in that: The one-way variable power optical unit is arranged at a position closer to the mask than the isotropic magnification correction optical unit along the optical axis of the projection optical system.

4. The laser processing device according to claim 1, characterized in that: While the linear beam is being scanned with respect to the one-way variable power optical unit, the distance between the convex cylindrical lens and the concave cylindrical lens can be changed.

5. The laser processing device according to claim 1, characterized in that: The curvature of the convex cylindrical lens is different from the curvature of the concave cylindrical lens.

6. The laser processing device according to any one of claims 1 to 5, characterized in that: The one-way variable magnification optical unit is configured such that its generatrix is ​​along the scanning direction of the linear light beam.

7. The laser processing device according to any one of claims 1 to 5, characterized in that: The one-way variable magnification optical unit is configured such that its generatrix is ​​along a direction perpendicular to the scanning direction of the linear light beam.

8. The laser processing device according to any one of claims 1 to 5, characterized in that: The one-way variable magnification optical unit is configured such that its generatrix is ​​along a direction inclined relative to a direction parallel to a scanning direction of the linear light beam or a direction perpendicular to the scanning direction of the linear light beam.

9. The laser processing device according to any one of claims 1 to 5, characterized in that: The laser processing device further includes an actuator capable of rotating the one-way variable magnification optical unit around an optical axis.

10. A projection optical system of a laser processing device, which can project a linear beam that has passed through a mask onto a workpiece while scanning, characterized in that: The projection optical system of the laser processing device has a one-way variable magnification optical unit, which is obtained by arranging a convex cylindrical lens and a concave cylindrical lens opposite to each other. The one-way variable magnification optical unit is configured such that when the linear light beam is scanned, the linear light beam passes through the one-way variable magnification optical unit while changing the position of the incident surface in the beam width direction. The projection magnification in one direction can be changed by changing the distance between the convex cylindrical lens and the concave cylindrical lens along the optical axis.

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