Laser processing method

Abstract

This technology provides a method for forming a precise square grid-like aperture pattern on a large-area target film in a short amount of time. [Solution] The laser processing method processes a target film formed on a substrate with a laser beam. The laser processing method comprises setting a plurality of processing areas on the target film, setting a square grid-shaped target path in each of the processing areas, moving the irradiation point of the galvanometer scanner so that the irradiation point of the laser beam passes through the target path, and switching the processing area in which the irradiation point is moved by moving the galvanometer scanner relative to the substrate, thereby forming a square grid-shaped aperture pattern spanning a plurality of processing areas. The laser processing method further comprises obtaining a measurement result of the deviation between the target path and the aperture pattern, and correcting the target path according to the deviation.

Description

Technical Field

[0001] This disclosure relates to a laser processing method.

Background Art

[0002] The radio wave absorber described in Patent Document 1 has a first dielectric layer, a conductive layer, a second dielectric layer, a radio wave reflection layer, and a third dielectric layer in this order. The conductive layer consists of a plurality of conductors and gaps that arrange the plurality of conductors apart from each other, and the plurality of conductors are insulated from each other. On the conductive layer, a first slit and a second slit that are orthogonal to each other are formed. The first slit and the second slit form a square lattice. The first slit and the second slit are formed by forming a spot of a laser beam on the surface of the conductive layer and scanning the spot.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In laser processing, it is conceivable to use a galvanometer scanner. The galvanometer scanner can move the irradiation point of the laser beam at high speed. However, the size of the movement range of the irradiation point by the galvanometer scanner is finite. Also, there may be a deviation between the movement path of the irradiation point and the target path. As a factor of the deviation, optical distortion of the galvanometer scanner is conceivable.

[0005] One embodiment of this disclosure provides a technique for forming an accurate square lattice-shaped opening pattern on a large-area target film in a short time.

Means for Solving the Problems

[0006] A laser processing method according to one embodiment of the present disclosure processes a target film formed on a substrate with a laser beam. The laser processing method comprises setting a plurality of processing regions on the target film, setting a square grid-shaped target path in each of the processing regions, moving the irradiation point of a galvanometer scanner so that the irradiation point of the laser beam passes through the target path, and switching the processing region in which the irradiation point is moved by moving the galvanometer scanner relative to the substrate, thereby forming a square grid-shaped aperture pattern spanning a plurality of processing regions. The laser processing method further comprises obtaining a measurement result of the deviation between the target path and the aperture pattern, and correcting the target path according to the deviation. [Effects of the Invention]

[0007] According to one embodiment of the present disclosure, a precise square grid-like opening pattern can be formed on a large-area target film in a short time. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a perspective view showing an example of a laser processing apparatus. [Figure 2] Figure 2 is a perspective view showing an example of a galvanometer scanner. [Figure 3] Figure 3 is a flowchart showing an example of a laser processing method. [Figure 4] Figure 4 is a perspective view showing an example of a machining area. [Figure 5] Figure 5 shows an example of a combination of part of the target path and part of the opening pattern. [Figure 6] Figure 6 shows an example of correction for the first straight section. [Figure 7] Figure 7 shows another example of the correction for the first straight line section. [Figure 8] Figure 8 shows an example of a radio wave absorber. [Figure 9] Figure 9 shows an example of the aperture pattern of the conductive layer shown in Figure 8. [Modes for carrying out the invention]

[0009] Embodiments of this disclosure will be described below with reference to the drawings. In each drawing, identical or similar components are denoted by the same reference numerals, and their descriptions may be omitted. In each drawing, the X-axis, Y-axis, and Z-axis directions are perpendicular to each other, the X-axis and Y-axis directions are horizontal, and the Z-axis direction is vertical.

[0010] The X-axis direction includes the positive X-axis direction and the negative X-axis direction, which is the opposite direction to the positive X-axis direction. The Y-axis direction includes the positive Y-axis direction and the negative Y-axis direction, which is the opposite direction to the positive Y-axis direction. The Z-axis direction includes the positive Z-axis direction and the negative Z-axis direction, which is the opposite direction to the positive Z-axis direction. The positive Z-axis direction is upward, and the negative Z-axis direction is downward.

[0011] An example of a laser processing apparatus 1 will be described with reference to Figure 1, etc. The laser processing apparatus 1 processes a target film 110 formed on a substrate 100 with a laser beam. At the point of irradiation of the laser beam, the target film 110 changes state from solid to gas and scatters, or scatters while remaining in the solid state. As a result, the target film 110 can be locally removed. The laser processing apparatus 1 includes, for example, a stage 10, a stopper 15, a first moving device 20, a processing head 30, a second moving device 40, and a control device 50.

[0012] Stage 10 holds the substrate 100 on which the target film 110 is formed. Stage 10 holds the substrate 100 horizontally from below, for example, with the target film 110 facing upwards. Stage 10 may have a plurality of free rollers 11. The plurality of free rollers 11 are arranged at intervals. The plurality of free rollers 11 roll while in contact with the lower surface of the substrate 100, reducing frictional resistance during transport of the substrate 100. The stopper 15 abuts against two sides of the substrate 100 to position the substrate 100.

[0013] The first moving device 20 moves the substrate 100 relative to the stage 10. The first moving device 20 is, for example, a belt conveyor 21. The stage 10 is divided into a plurality of divided stages 12 in the X-axis direction, and a belt conveyor 21 is arranged between adjacent divided stages 12. The belt conveyor 21 moves the substrate 100 relative to the stage 10 in the Y-axis direction. A plurality of belt conveyors 21 may be provided.

[0014] The processing head 30 irradiates a laser beam onto the substrate 100 held by the stage 10. As shown in FIG. 2, the processing head 30 has a galvanometer scanner 31. The galvanometer scanner 31 includes, for example, an X-axis mirror 32, an X-axis motor 33, a Y-axis mirror 34, a Y-axis motor 35, and an fθ lens 36.

[0015] By rotating the X-axis mirror 32 under the control of the control device 50 by the X-axis motor 33, the irradiation point P of the laser beam LB on the target film 110 moves in the X-axis direction. Also, by rotating the Y-axis mirror 34 under the control of the control device 50 by the Y-axis motor 35, the irradiation point P of the laser beam LB on the target film 110 moves in the Y-axis direction.

[0016] The control device 50 stores in advance information indicating the relationship between the rotation angles of the X-axis mirror 32 and the Y-axis mirror 34 and the XY coordinates of the irradiation point P, and controls the position of the irradiation point P while referring to the stored information. The relationship between the rotation angles of the X-axis mirror 32 and the Y-axis mirror 34 and the XY coordinates of the irradiation point P is stored in the form of an equation or a table.

[0017] The fθ lens 36 forms a focal plane perpendicular to the Z-axis direction. While the X-axis mirror 32 or the Y-axis mirror 34 moves the irradiation point P in the X-axis direction or the Y-axis direction, the fθ lens 36 maintains the shape and dimensions of the irradiation point P on the upper surface of the target film 110. The height of the irradiation point P coincides with the height of the focal plane in this embodiment, but it does not have to coincide with the height of the focal plane, and may be higher or lower than the height of the focal plane.

[0018] The processing head 30 includes an oscillator 37. The oscillator 37 oscillates a laser beam. The wavelength of the laser beam is appropriately set according to the material of the target film 110. The oscillator 37 may be either a continuous wave laser or a pulsed laser. The continuous wave laser continuously oscillates with a constant output. The pulsed laser repeatedly oscillates with a pulsed output at a constant frequency.

[0019] As shown in FIG. 1, the second moving device 40 moves the processing head 30 relative to the stage 10. The second moving device 40 has, for example, an X-axis moving mechanism 41 and a Y-axis moving mechanism 42. The X-axis moving mechanism 41 moves the processing head 30 in the X-axis direction. The Y-axis moving mechanism 42 moves the processing head 30 in the Y-axis direction. The X-axis moving mechanism 41 and the Y-axis moving mechanism 42 each include, for example, a rotary motor and a ball screw that converts the rotational motion of the rotary motor into a linear motion. Note that the X-axis moving mechanism 41 and the Y-axis moving mechanism 42 may each include a linear motor.

[0020] The control device 50 is, for example, a computer. The control device 50 includes an arithmetic unit 51 such as a CPU (Central Processing Unit) and a storage unit 52 such as a memory. A program for controlling various processes executed in the laser processing apparatus 1 is stored in the storage unit 52. The control device 50 controls the operation of the laser processing apparatus 1 by causing the arithmetic unit 51 to execute the program stored in the storage unit 52.

[0021] The control device 50 includes an electronic circuit such as a CPU, a GPU (Graphics Processing Unit), an FPGA (Field Programmable Gate Array), or an ASIC (Application Specific Integrated Circuit), and executes various control operations described in the present specification by executing instruction codes stored in a memory or by being circuit-designed for a specific purpose.

[0022] An example of a laser processing method will be described with reference to Figure 3, etc. The laser processing method includes, for example, steps S101 to S107. Steps S101 to S107 are performed under the control of the control device 50.

[0023] First, the control device 50 sets multiple processing areas 120 (see Figure 4) on the target film 110 (step S101). The processing areas 120 are the areas in which the galvanoscanner 31 moves the irradiation point P. The processing areas 120 are preferably rectangular so that they can be arranged without gaps. The rectangle may have two sides parallel to the X-axis direction and two sides parallel to the Y-axis direction. The processing areas 120 can be arranged without gaps in the X-axis direction and the Y-axis direction.

[0024] Multiple processing areas 120 are basically the same size. However, some processing areas 120 may have a different size from the remaining processing areas 120 to match the size of the target film 110. From the viewpoint of reducing the number of processing area 120 switching cycles and consequently shortening the processing time, a larger size of processing area 120 is preferable.

[0025] The length of each side of the processing area 120 is preferably 150 mm or more, and more preferably 200 mm or more, from the viewpoint of reducing the number of times the processing area 120 is switched and, consequently, shortening the processing time. While the length of each side of the processing area 120 is preferable as long as possible, it may be 300 mm or less from the viewpoint of miniaturizing the fθ lens 36.

[0026] Next, the control device 50 sets a square grid-shaped target path 130 in each processing area 120 (step S102). The target path 130 may have a plurality of first straight sections 131 and a plurality of second straight sections 132 that intersect each of the first straight sections 131, as shown in Figure 4.

[0027] Before performing the correction described later (step S107), the multiple first straight sections 131 are parallel to each other, the multiple second straight sections 132 are parallel to each other, and the first straight sections 131 and the second straight sections 132 are perpendicular to each other. The first straight sections 131 are, for example, parallel to the Y-axis direction, and the second straight sections 132 are, for example, parallel to the X-axis direction.

[0028] Next, the galvanometer scanner 31 moves the irradiation point P so that the irradiation point P of the laser beam LB passes through the target path 130 (step S103). The galvanometer scanner 31 can move the irradiation point P at a higher speed than the second moving device 40, thus reducing the processing time. While the galvanometer scanner 31 moves the irradiation point P, the second moving device 40 stops moving the processing head 30.

[0029] The galvanometer scanner 31 may move the irradiation point P so that it passes through each first linear section 131 and each second linear section 132 only once in one direction. This reduces processing time compared to when the irradiation point P passes through each first linear section 131 and each second linear section 132 multiple times. It also allows for a narrower line width in the aperture pattern.

[0030] Next, the control device 50 checks whether laser processing has been completed in all processing areas 120 (step S104). If there are any unprocessed processing areas 120 (step S104, NO), the second moving device 40 moves the galvanometer scanner 31 relative to the substrate 100 to switch the processing area 120 in which the irradiation point P is moved (step S105).

[0031] In this embodiment, when switching the processing area 120, the galvanometer scanner 31 is moved in the X-axis or Y-axis direction, but the substrate 100 may also be moved in the X-axis or Y-axis direction. At least one of the galvanometer scanner 31 and the substrate 100 should be moved in the X-axis or Y-axis direction. In other words, when switching the processing area 120, the galvanometer scanner 31 and the substrate 100 should be moved relative to each other.

[0032] Incidentally, the movement speed V1 of the illumination point P by the galvanoscanner 31 is faster than the relative movement speed V2 of the galvanoscanner 31 with respect to the substrate 100 when switching the processing area 120. This is because the X-axis mirror 32 and Y-axis mirror 34 are light and can rotate at high speed. V1 is preferably 5 times or more than V2, and more preferably 10 times or more. V1 may be 100 times or less than V2.

[0033] After step S105, the control device 50 repeats the processing from step S103 onwards. The control device 50 controls the formation of a square grid-like opening pattern spanning multiple processing areas 120 by repeatedly performing steps S103 and S105 alternately. The opening pattern is continuously connected at the boundaries of adjacent processing areas 120. By repeatedly performing steps S103 and S105 alternately, a large area target film 110 can be processed in a short time.

[0034] If the target film 110 is rectangular, the length of each side of the target film 110 is preferably 300 mm or more, and more preferably 500 mm or more. While longer sides of the target film 110 are preferable, they may be 3000 mm or less from the viewpoint of handling the substrate 100.

[0035] When laser processing is completed in all processing areas 120 (step S104, YES), the control device 50 performs the processing from step S106 onwards. First, the control device 50 obtains the measurement result of the deviation between the target path 130 and the aperture pattern (step S106). The aperture pattern matches the actual movement path of the irradiation point P in step S103.

[0036] The control device 50 pre-stores information showing the relationship between the rotation angles of the X-axis mirror 32 and the Y-axis mirror 34 and the XY coordinates of the irradiation point P, and controls the position of the irradiation point P while referring to the stored information. However, the above-mentioned deviation may occur. Possible causes of the above-mentioned deviation include optical distortion of the galvanometer scanner 31, for example, distortion of the fθ lens 36. The above-mentioned deviation is measured by an inspection device (not shown).

[0037] The inspection device captures an image of the target film 110 after laser processing using a camera, and measures the deviation between the target path 130 and the aperture pattern by image processing of the captured image. The inspection device transmits the measurement result of the deviation to the control device 50. This allows the control device 50 to obtain the measurement result of the deviation. The inspection device is provided separately from the laser processing device 1, but it may also be provided as part of the laser processing device 1.

[0038] The inspection device does not need to image the entire aperture pattern; it may image only a portion of the aperture pattern. The measurement of the deviation is possible as long as laser processing is completed in at least one processing area 120. Therefore, the measurement of the deviation does not need to be performed on a target film 110 that is the same size as the product; it may be performed on a target film 110 that is smaller than the product.

[0039] After step S106, the control device 50 corrects the target path 130 (step S107). The control device 50 corrects the target path 130 according to the deviation acquired in step S106.

[0040] Figure 5 shows an example of correction of the first straight section 131. By correcting the target path 130, the deviation between the target path 130 before correction and the aperture pattern can be reduced in the next laser processing. Therefore, an accurate square grid-like aperture pattern can be formed on a large area target film 110 in a short time.

[0041] The control device 50 may perform steps S101 to S107 multiple times until the deviation falls within the acceptable range.

[0042] Referring to Figure 6, an example of correction of the first linear section 131 will be described. In Figure 6, 131 is the first linear section before correction, 131A is the first linear section after correction, and 141 is the actual movement path of the irradiation point P when the galvanoscanner 31 moves the irradiation point P so that the irradiation point P passes through the first linear section 131 before correction. 141 is part of the actual aperture pattern 140.

[0043] If the movement path 141 is a straight line before the correction of the first straight section 131, the correction of the first straight section 131 includes, for example, rotating the first straight section 131. Note that, as shown in Figure 5, it is not necessary to rotate all of the first straight sections 131; it is sufficient to rotate at least one of the first straight sections 131. Before correction, the first straight sections 131 are parallel to the Y-axis direction, and the first straight sections 131 overlap at the boundary of adjacent machining regions 120 in the Y-axis direction.

[0044] The magnitude and direction of rotation of the first linear section 131 are set according to the magnitude and direction of the displacement ΔX of the opening pattern 140 in the X-axis direction at the boundary of adjacent machining areas 120 in the Y-axis direction. The larger the magnitude of ΔX, the greater the magnitude of rotation. The rotation center of the first linear section 131 is set, for example, at the intersection of the first linear section 131 and the movement path 141.

[0045] The corrected first straight section 131A only needs to be symmetrical with respect to the movement path 141, with reference to the first straight section 131 before correction. Therefore, it is not necessary to measure the magnitude and direction of the deviation ΔX. Correction of the first straight section 131 is possible as long as laser processing is completed in at least one processing area 120.

[0046] Although not shown in the diagram, the correction of the second straight section 132 can be performed in the same way as the correction of the first straight section 131. Before correction, the second straight section 132 is parallel to the X-axis direction, and the second straight sections 132 overlap at the boundary of adjacent machining regions 120 in the X-axis direction.

[0047] The magnitude and direction of rotation of the second linear section 132 are set, for example, according to the magnitude and direction of the displacement ΔY of the opening pattern 140 in the Y-axis direction at the boundary of adjacent machining regions 120 in the X-axis direction. The corrected second linear section should be symmetrical with respect to the actual movement path of the irradiation point P, with reference to the second linear section 132 before correction.

[0048] Referring to Figure 7, another example of correction of the first linear section 131 will be described. In Figure 7, 131 is the first linear section before correction, 131A is the first linear section after correction, and 141 is the actual movement path of the irradiation point P when the galvanoscanner 31 moves the irradiation point P so that the irradiation point P passes through the first linear section 131 before correction. 141 is part of the actual aperture pattern 140.

[0049] In Figure 7, 141A is an approximation line of the travel path 141. The approximation line 141A is a polyline created by connecting multiple points of the travel path 141 with straight lines. For example, the approximation line 141A is a polyline that includes a straight line 142A connecting one end of the travel path 141 to the center, and a straight line 143A connecting the other end of the travel path 141 to the center.

[0050] As shown in Figure 7, if the movement path 141 is curved before correction of the first straight section 131, the movement paths 141 intersect at the boundary of adjacent machining regions 120 in the Y-axis direction. Therefore, it is possible to determine whether the movement path 141 is curved or not by whether or not the movement paths 141 intersect at the boundary of adjacent machining regions 120 in the Y-axis direction.

[0051] If the movement path 141 is a curve before the correction of the first straight section 131, the correction of the first straight section 131 includes, for example, deforming the first straight section 131 into a polylinear shape by rotating it at predetermined intervals. Note that it is not necessary to correct all of the first straight sections 131; it is sufficient to correct at least one of the first straight sections 131.

[0052] The corrected first straight section 131A should be symmetrical with respect to the approximation line 141A of the movement path 141, with respect to the first straight section 131 before correction. The number of sections is 2 in this embodiment, but it can be 2 or more and is not particularly limited. For example, the control device 50 may set the number of sections to 2 in the first step S107 and set the number of sections to 3 or more in the second step S107. If the deviation between the target path 130 before correction and the aperture pattern 140 cannot be kept within an acceptable range even after the first correction, the number of sections may be increased.

[0053] Although not shown in the diagram, the correction of the second straight section 132 can be performed in the same way as the correction of the first straight section 131. The correction of the second straight section 132 includes, for example, transforming the second straight section 132 into a polylinear shape by rotating it in predetermined intervals. The number of intervals can be two or more, and is not particularly limited. The corrected second straight section should be symmetrical with respect to the approximation line 141A of the movement path 141, with respect to the second straight section 132 before correction.

[0054] An example of the radio wave absorber 200 will be described with reference to Figures 8 and 9. The radio wave absorber 200 absorbs radio waves of a desired frequency and suppresses diffuse reflection of those radio waves. It is preferable that the radio wave absorber 200 is transparent so that the opposite side can be seen from one side of the radio wave absorber 200.

[0055] The radio wave absorber 200 is, for example, plate-shaped and includes a first main surface 201 to which radio waves are incident and a second main surface 202 facing the opposite direction from the first main surface 201. The radio wave absorber 200 comprises a first dielectric layer 210, a conductive layer 220, a second dielectric layer 230, a radio wave reflective layer 240, and a third dielectric layer 250 in this order, from the first main surface 201 toward the second main surface 202. The second dielectric layer 230 is an example of a substrate 100, and the conductive layer 220 is an example of a target film 110.

[0056] The radio wave absorber 200 may further include an adhesive layer 260 between the first main surface 201 and the second main surface 202. The adhesive layer 260 is placed, for example, between the first dielectric layer 210 and the conductive layer 220, between the second dielectric layer 230 and the radio wave reflective layer 240, and between the radio wave reflective layer 240 and the third dielectric layer 250. The arrangement of the adhesive layer 260 can be changed as appropriate.

[0057] The first dielectric layer 210 protects the conductive layer 220. The first dielectric layer 210 is made of glass, ceramics, or resin. From the viewpoint of weight reduction, resin is preferred. Specific examples of resins include polyethylene terephthalate (PET) resin, polycarbonate (PC) resin, or acrylic resin. On the other hand, from the viewpoint of scratch resistance, glass or ceramics are preferred.

[0058] When the first dielectric layer 210 is a glass substrate or a ceramic substrate, its thickness is, for example, 0.2 mm to 4.0 mm, preferably 0.3 mm to 2.5 mm, and more preferably 0.3 mm to 1.0 mm. On the other hand, when the first dielectric layer 210 is a resin substrate, its thickness is, for example, 0.4 mm to 5.0 mm, preferably 0.5 mm to 3.5 mm, and more preferably 0.5 mm to 1.5 mm.

[0059] When the first dielectric layer 210 is a glass substrate, the tanδ (also called dielectric loss tangent) of the glass substrate is preferably 0.025 or less, more preferably 0.020 or less, and even more preferably 0.010 or less. The lower limit of the tanδ of the glass substrate is not particularly limited, but may be 0.0001 or more. Furthermore, the relative permittivity of the glass substrate is preferably 8 or less, and even more preferably 7 or less. The lower limit of the relative permittivity of the glass substrate is not particularly limited, but may be 3.5 or more.

[0060] When the first dielectric layer 210 is a resin substrate, the tanδ of the resin substrate is preferably 0.2 or less, and more preferably 0.1 or less. The lower limit of the tanδ of the resin substrate is not particularly limited, but may be 0.0005 or more. Furthermore, the relative permittivity of the resin substrate is preferably 5 or less, and more preferably 4 or less. The lower limit of the relative permittivity of the resin substrate is not particularly limited, but may be 2 or more.

[0061] Here, tanδ is a value expressed as ε² / ε¹ using the complex permittivity, where ε¹ is the relative permittivity and ε² is the dielectric loss. The smaller the value of tanδ, the less the radio wave is absorbed in that frequency band. Tanδ and relative permittivity are values ​​measured at a measurement frequency of 1 GHz according to the method specified in IEC (International Electrotechnical Commission) 61189-2-721 (2015).

[0062] The ratio (T1 / T2) of the thickness of the first dielectric layer 210 (T1) to the thickness of the second dielectric layer 230 (T2) is, for example, 0.05 to 0.75. The first dielectric layer 210 is intended to protect the conductive layer 220, so it may be thinner than the second dielectric layer 230.

[0063] As shown in Figure 9, the conductive layer 220 includes a plurality of conductors 221 that are spaced apart from each other and insulated from one another. The conductors 221 are transparent conductive films such as ITO (indium tin oxide) films or Low-E (low-emissivity) films. The conductive layer 220 is formed by, for example, a vapor deposition method or a sputtering method. The aperture pattern 222 of the conductive layer 220 is formed by a laser processing apparatus 1.

[0064] The opening pattern 222 of the conductive layer 220 includes multiple first slits 223 and second slits 224 that are orthogonal to each other. The first slits 223 and second slits 224 are formed in a square grid pattern, separating adjacent conductors 221. The conductors 221 are formed in a rectangular shape, including squares.

[0065] The conductors 221 may be the same size or may be of different sizes. The size of the conductors 221 is set according to the wavelength of the radio waves they absorb. The longer the wavelength of the radio waves, the larger the size of the conductors 221. In other words, the lower the frequency of the radio waves, the larger the size of the conductors 221.

[0066] The conductive layer 220 may be a so-called FSS (Frequency Selective Surface). The conductive layer 220 reflects a portion of the radio waves and transmits the rest. The radio waves that have passed through the conductive layer 220 are reflected by the radio wave reflection layer 240. The radio waves reflected by the conductive layer 220 and the radio waves reflected by the radio wave reflection layer 240 interfere with each other and cancel each other out. As a result, the radio waves are absorbed.

[0067] When radio waves reach the conductive layer 220, free electrons in the conductor 221 move in the opposite direction to the electric field direction of the radio waves, causing a current to flow in the conductor 221. At the same time, energy is periodically accumulated and released in the gaps between the conductors 221 due to the generated electric field. As a result, a propagation delay occurs in the radio waves that pass through the conductive layer 220. In other words, a delay time occurs between the time the radio waves enter the conductive layer 220 and the time they are re-radiated. Therefore, the distance between the conductive layer 220 and the radio wave reflective layer 240 can be reduced to less than λ / 4, thereby thinning the radio wave absorber 200. The distance between the conductive layer 220 and the radio wave reflective layer 240 is preferably 1.5 mm to 20 mm, more preferably 2 mm to 10 mm, and even more preferably 2 mm to 5 mm.

[0068] The thickness of the conductive layer 220 is not particularly limited, but for example, if the conductive layer 220 is a Low-E (low-emissivity) film, it is 50 nm to 300 nm.

[0069] The following additional information is disclosed regarding the above embodiments, etc. [Note 1] A laser processing method for processing a target film formed on a substrate with a laser beam, Setting multiple processing regions in the aforementioned target film, Setting a square grid-like target path in each of the aforementioned processing areas, The galvanometer scanner moves the irradiation point so that the irradiation point of the laser beam passes through the target path, and the galvanometer scanner moves relative to the substrate to switch the processing area in which the irradiation point moves, and by repeatedly performing these actions alternately, a square grid-like aperture pattern spanning multiple processing areas is formed. It has, To obtain the measurement results of the deviation between the target path and the opening pattern, Correcting the target path according to the aforementioned deviation, A laser processing method further comprising [the specified feature]. [Note 2] The target path comprises a plurality of first straight sections and a plurality of second straight sections intersecting each of the first straight sections. The laser processing method according to Appendix 1, wherein correcting the target path includes rotating at least one of the first straight sections. [Note 3] The laser processing method according to Appendix 2, wherein the magnitude and direction of rotation of the first linear portion are set according to the magnitude and direction of the misalignment of the aperture pattern at the boundary of adjacent processing areas. [Note 4] The target path comprises a plurality of first straight sections and a plurality of second straight sections intersecting each of the first straight sections. The laser processing method according to Appendix 1, wherein correcting the target path includes correcting it in a polylinear manner by rotating at least one of the first straight sections at predetermined intervals. [Note 5] The laser processing method according to any one of the appendices 1 to 4, wherein the movement speed of the irradiation point by the galvanoscanner is faster than the relative movement speed of the galvanoscanner with respect to the substrate when switching the processing area. [Note 6] The target path comprises a plurality of first straight sections and a plurality of second straight sections intersecting each of the first straight sections. The laser processing method according to any one of the appendices 1 to 5, wherein the galvanometer scanner moves the irradiation point so that the irradiation point passes through each of the first linear sections and each of the second linear sections only once in one direction. [Note 7] The aforementioned substrate is a glass substrate, as described in any one of the appendices 1 to 6, for the laser processing method. [Note 8] The laser processing method described in any one of the appendices 1 to 7, wherein the target film is a conductive film.

[0070] The laser processing method described above is not limited to the embodiments described herein. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. These also naturally fall within the technical scope of this disclosure. [Explanation of symbols]

[0071] 1. Laser processing device 10 stages 20 1st mobile device 30 Machining Heads 31 Galvanometer Scanner 40 Second mobile device 50 Control device 100 circuit boards 110 Target membrane 120 Processing area 130 Target Route 140 Opening Patterns

Claims

1. A laser processing method for processing a target film formed on a substrate with a laser beam, Setting multiple processing regions in the aforementioned target film, Setting a square grid-like target path in each of the aforementioned processing areas, The galvanometer scanner moves the irradiation point so that the irradiation point of the laser beam passes through the target path, and the galvanometer scanner moves relative to the substrate to switch the processing area in which the irradiation point moves, and by repeatedly performing these actions alternately, a square grid-like aperture pattern spanning multiple processing areas is formed. It has, To obtain the measurement results of the deviation between the target path and the opening pattern, Correcting the target path according to the aforementioned deviation, A laser processing method further comprising [the specified feature].

2. The target path comprises a plurality of first straight sections and a plurality of second straight sections intersecting each of the first straight sections. The laser processing method according to claim 1, wherein correcting the target path includes rotating at least one of the first straight sections.

3. The laser processing method according to claim 2, wherein the magnitude and direction of rotation of the first linear portion are set according to the magnitude and direction of the misalignment of the aperture pattern at the boundary of adjacent processing areas.

4. The target path comprises a plurality of first straight sections and a plurality of second straight sections intersecting each of the first straight sections. The laser processing method according to claim 1, wherein correcting the target path includes deforming at least one of the first straight sections into a broken line by rotating it at predetermined intervals.

5. The laser processing method according to any one of claims 1 to 4, wherein the movement speed of the irradiation point by the galvanoscanner is faster than the relative movement speed of the galvanoscanner with respect to the substrate when switching the processing area.

6. The target path comprises a plurality of first straight sections and a plurality of second straight sections intersecting each of the first straight sections. The laser processing method according to any one of claims 1 to 4, wherein the galvanometer scanner moves the irradiation point such that the irradiation point passes through each of the first linear sections and each of the second linear sections only once in one direction.

7. The laser processing method according to any one of claims 1 to 4, wherein the substrate is a glass substrate.

8. The laser processing method according to any one of claims 1 to 4, wherein the target film is a conductive film.

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