JP2006351977A - Laser processing apparatus and laser processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform processing by laser beam irradiation to the entire area of a large-sized substrate just by equal speed movement. <P>SOLUTION: A laser processing apparatus 1 is provided with a substrate support 11 for which the outer surface side or inner surface side of a columnar surface is constituted as a support surface 11a of a workpiece W, and irradiation heads 13-1 and 13-2, etc., for irradiating the workpiece W supported by the support surface 11a of the substrate support part 11 with laser beams. By the relative unidirectional movement of the irradiation heads 13-1 and 13-2, etc., to the support surface 11a on a track centering the axis ϕ of the columnar surface constituting the support surface 11a, the irradiation heads 13-1 and 13-2, etc. , are scanned for the entire area of the workpiece W supported by the support surface 11a. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a laser processing apparatus and a laser processing method, and more particularly to a laser processing apparatus and a laser processing method that are suitably used for a process for efficiently irradiating a laser beam to the entire region of a large-area processing substrate.

  In a flat display device such as a liquid crystal display device or an organic EL display device, a thin film transistor (TFT) is used as a switching element for performing an active matrix display of a plurality of pixels. In particular, TFTs (polycrystalline silicon TFTs) that use polycrystalline silicon (poly-Si) or microcrystalline silicon (μc-Si) in the active region have a fast response speed and very excellent characteristics as a constituent material for switching elements. have. As a manufacturing technique of such a polycrystalline silicon TFT, a so-called low-temperature polysilicon process for crystallizing a semiconductor thin film by laser annealing by laser light irradiation has been developed and put into practical use. By using a low-temperature polysilicon process, it is possible to use a resin material as a substrate, so that a flat display device that can be flexibly bent is realized and the cost of the flat display device can be reduced.

  In the low-temperature polysilicon process as described above, when the laser annealing process is performed on a substrate having a large area, a laser beam in which an irradiation region is shaped into a predetermined shape is two-dimensionally applied to the processing surface. Intermittent irradiation while scanning. At this time, the laser beam irradiation positions are scanned so as to be overlapped so that each irradiation position is irradiated with the laser beam a plurality of times, thereby irradiating the laser beam with uniform energy over the entire surface of the substrate. The crystal grain size is made uniform. (See the following Patent Document 1).

JP 2000-340506 A (see paragraphs 10 to 14)

  However, the laser processing apparatus used for the above-described laser annealing process is configured to irradiate laser light in pulses in synchronization with the step movement of the substrate for the purpose of irradiating laser light uniformly over a wider range. . Then, in the annealing using such a laser processing apparatus, as described above, a plurality of times of pulse irradiation are performed on each irradiation position while shifting the irradiation region of the laser beam formed into a long linear shape. That process is performed. Therefore, for example, in the process of annealing a part of the elements arranged for the drive substrate of the display device, most of the irradiating energy is expended in a region where it is not used, which is wasteful. Furthermore, a configuration in which laser light is irradiated over a wide range has a large thermal load on the substrate, and is not suitable for application to a process using a plastic substrate.

  For this reason, while moving the irradiation position of the laser beam to the substrate at a constant speed, the thermal load on the substrate is reduced by controlling the ON / OFF of the laser beam and irradiating only the desired position with the laser beam. It is desired to develop a laser processing apparatus that can do this. However, in order to move the irradiation position of the laser light with respect to the substrate at a constant speed, a spatial acceleration region is required until the substrate or the laser light irradiation head reaches the speed of the constant speed movement. For this reason, there has been a problem that the apparatus becomes larger.

  Therefore, the present invention provides a laser processing apparatus capable of performing processing by laser light irradiation over the entire area of the substrate by a constant velocity motion, and a laser processing method using the laser processing apparatus. The purpose is to do.

  In order to achieve such an object, the laser processing apparatus of the present invention includes a substrate support portion in which an outer surface side or an inner surface side of a cylindrical surface is configured as a support surface of a processing substrate. Further, an irradiation head for irradiating the processing substrate supported on the support surface of the substrate support portion with laser light is provided. Then, the substrate support part and the irradiation head move in one direction relative to the support surface on the trajectory centering on the axis of the cylindrical surface constituting the support surface of the substrate support part, Accordingly, the irradiation head is configured to scan the entire area of the processing substrate supported on the support surface.

  In the laser processing apparatus having such a configuration, the support surface of the substrate support portion is the outer surface side or the inner surface side of the cylindrical surface. For this reason, in a state where the processing substrate is supported on the support surface, the surface to be processed of the processing substrate constitutes the outer surface side or the inner surface side of the cylindrical surface. The irradiation head for irradiating the processing substrate supported by the support surface with laser light is directed toward the support surface in one direction on the orbit centering on the axis of the cylindrical surface constituting the support surface. Move relatively. Therefore, the relative movement of the irradiation head with respect to the surface to be processed of the processing substrate supported by the substrate support unit is continuously performed only by the rotational motion around the axis of the cylindrical surface without moving the irradiation head and the substrate support unit. Will be done.

  The laser processing method of the present invention is a laser processing method for performing processing by laser light irradiation over the entire surface to be processed by irradiating the surface to be processed of the substrate while relatively scanning the laser beam. . In particular, the processing substrate is installed such that the outer surface side or the inner surface side of the cylindrical surface is a surface to be processed. And when irradiating a laser beam from an irradiation head toward the to-be-processed surface installed in this way, the said with respect to the to-be-processed surface on the track | orbit centering on the axis | shaft of the cylindrical surface which comprises a to-be-processed surface By the movement of the irradiation head in one relative direction, the laser light emitted from the irradiation head is scanned over the entire area of the surface to be processed.

  In such a processing method, the laser beam is applied to the entire area of the processing surface by moving the irradiation head in one relative direction with respect to the processing surface constituting the outer surface side or the inner surface side of the cylindrical surface. Scanning. For this reason, the relative movement of the irradiation head with respect to the processing surface of the processing substrate supported by the substrate support unit is continuously performed by a rotational movement around the axis of the cylindrical surface without moving the irradiation head and the substrate support unit. To be done.

  As described above, according to the laser processing apparatus and the laser processing method of the present invention, the relative movement of the irradiation head with respect to the surface to be processed of the processing substrate is continuously performed only by the rotational motion. It is possible to move the irradiation position of the laser beam on the processing substrate without moving the part. Thereby, it is possible to perform processing by laser light irradiation over the entire area of the substrate by constant velocity movement while keeping the apparatus small.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each embodiment, a configuration of a laser processing apparatus for performing a process of irradiating a predetermined irradiation position with laser light on the entire surface of a large-area processing substrate will be described, and then laser processing using a single laser processing apparatus will be described. A method will be described.

<First Embodiment>
FIG. 1 is a perspective view showing a schematic configuration of the laser processing apparatus of the first embodiment. The laser processing apparatus 1 according to the first embodiment shown in this figure includes a substrate support 11 for supporting a processing substrate W, and a plurality of irradiation heads 13 for irradiating a processing substrate supported by the substrate support 11 with laser light. -1, 13-2,... (Four here).

  Here, the board | substrate support part 11 is comprised as a cylindrical body (or cylindrical body), and the outer surface side of the cylindrical surface is comprised as the support surface 11a. The support surface 11a is configured to hold the processing substrate W by suction. There is no particular limitation on the suction holding mechanism, and for example, an electrostatic suction method or a vacuum suction method may be used. The substrate support portion 11 is configured to be rotatable at a constant rotational speed v1 in one direction (here, counterclockwise) around the axis φ of the cylindrical surface formed by the support surface 11a. Furthermore, the board | substrate support part 11 may become a structure which can move at a fixed speed | rate in the axis | shaft (phi) direction of the cylindrical surface which the support surface 11a comprises. In the drawing, in order to explain the support surface 11a, a part of the processing substrate W is cut out.

  The irradiation heads 13-1, 13-2,... Are arranged so as to irradiate the laser beam toward the support surface 11a of the substrate support portion 11. These irradiation heads 13-1, 13-2,... Are configured using, for example, a semiconductor laser oscillator. The irradiation heads 13-1, 13-2,... Are arranged on a spiral trajectory that uniformly surrounds the entire area of the support surface 11a around the axis φ of the cylindrical surface formed by the support surface 11a. Assume that they are arranged in a positional relationship.

  FIG. 2 shows a diagram for explaining an example of the arrangement state and movement direction of the irradiation heads 13-1, 13-2,. FIG. 2 is a side view of the laser processing apparatus 1 viewed from the direction of the white arrow in FIG. It is assumed that the irradiation heads 13-1, 13-2,... Shown in this figure are arranged on the one spiral trajectory described above. These irradiation heads 13-1, 13-2,... Follow one spiral trajectory surrounding the processing substrate W supported by the substrate support portion 11 and the number of irradiation heads 13-1, 13-2,. (4) are preferably arranged at equally divided intervals, whereby an area to be processed by one irradiation head is equally shared and efficient processing is performed.

  As shown in FIGS. 1 and 2, the irradiation heads 13-1, 13-2,... Have a constant moving speed v <b> 2 in one direction along the above-described spiral trajectory while maintaining the respective positional relationship. It is configured to move in. The movement of the irradiation heads 13-1, 13-2,... On the spiral trajectory may be a relative movement with respect to the substrate support 11, and the substrate support 11 also moves in the axis φ direction. Is a movement combined with this movement. For this reason, the board | substrate support part 11 becomes a structure which can rotate with the fixed rotational speed v1. The moving speed v2 of the irradiation heads 13-1, 13-2,... Is preferably set as fast as possible for the purpose of increasing the efficiency of laser processing. In order to assist the mechanical limit of the moving speed v2 of the irradiation heads 13-1, 13-2,..., The rotational speed v1 of the substrate support 11 and the moving speed in the axis φ direction may be set.

  It should be noted that the relative movement of the irradiation heads 13-1, 13-2,... Relative to the substrate support portion 11 may be on a spiral trajectory that uniformly surrounds the entire support surface 11a. Therefore, as shown in FIG. 3, the irradiation heads 13-1, 13-2,... May move on individual (for example, quadruple) spiral trajectories. In this case, the entire support surface 11a is uniformly surrounded by these spiral tracks.

  In addition, as described at the end of the embodiment, each of the irradiation heads 13-1, 13-2,... Has a laser beam irradiation position on the processing surface Wa of the processing substrate W supported by the substrate support portion 11. And a laser irradiation mechanism for finely adjusting the depth of focus.

  The laser processing method using the laser processing apparatus 1 configured as described above is performed as follows.

  First, the processing substrate W is wound around the substrate support unit 11, and the processing substrate W is sucked and held on the support surface 11 a on the outer surface side of the substrate support unit 11. At this time, the processing surface Wa of the processing substrate W is directed outward so that the outer surface side of the cylindrical surface becomes the processing surface Wa.

  Next, each irradiation is performed such that the uppermost irradiation head among the irradiation heads 13-1, 13-2,... Is disposed above the uppermost end of the processing substrate W supported by the substrate support unit 11. Heads 13-1, 13-2,... Are installed.

  In this state, movement of the irradiation heads 13-1, 13-2,... On the spiral trajectory described above toward a predetermined direction (downward here) is started. At this time, the movement of the substrate support 11 may be started as necessary. Then, after the moving speed v2 of the irradiation heads 13-1, 13-2,... With respect to the substrate support portion 11 becomes a predetermined constant speed, the processing substrate W in which the uppermost irradiation head is supported by the substrate support portion 11 is further provided. .. Starts irradiation of the laser beam onto the processing surface Wa of the processing substrate W from each of the irradiation heads 13-1, 13-2,.

  The irradiation of the laser beam to the processing surface Wa of the processing substrate W from each irradiation head 13-1, 13-2,... Is performed while switching ON / OFF according to the irradiation region of the laser beam.

  Then, the relative movement of the irradiation heads 13-1, 13-2,... Relative to the surface Wa to be processed on the spiral trajectory centering on the axis φ of the cylindrical surface as described above causes the object to be covered. The entire region of the processing surface Wa is scanned with the laser beam irradiated from the irradiation heads 13-1, 13-2,. Further, after the irradiation head arranged at the lowermost part passes through a predetermined position at the lowermost end of the processing substrate W supported by the substrate support part 11, the irradiation heads 13-1, 13-2,. Stop moving.

  As described above, according to the first embodiment, the irradiation heads 13-1, 13-2,... With respect to the processing surface Wa of the processing substrate W arranged in the state of constituting the outer surface side of the cylindrical surface. Is moved in one relative direction to scan the entire region of the processing surface Wa with the laser beam. Therefore, relative movement of the irradiation heads 13-1, 13-2,... With respect to the processing surface Wa of the processing substrate W supported by the substrate support unit 11 is caused by the substrate support unit 11 and the irradiation head 13 being moved. .., 13-2,... Are continuously performed only by the rotational movement around the axis of the cylindrical surface without moving the arrangement positions.

  Therefore, when moving the irradiation position of the laser beam on the surface Wa to be processed, the substrate or the laser beam irradiation head is moved at a constant speed even when the processing of moving the irradiation position of the laser beam to the substrate at a constant speed is performed. No spatial acceleration area is needed to reach the speed of movement. For this reason, size reduction of the apparatus which performs such a process is achieved.

  In addition, while moving the irradiation position of the laser beam with respect to the substrate, a process of irradiating the laser beam only at a desired position by controlling ON / OFF of the laser beam is performed. For this reason, the irradiation process of the laser beam by which the thermal load with respect to the board | substrate was reduced by irradiating only a required part with a laser beam is performed.

  As a result, by adjusting the moving speed of the laser beam Lh at a high speed, it becomes possible to perform the laser beam irradiation process with a reduced thermal load on the substrate W. For example, a semiconductor thin film on the substrate W is crystallized. It is possible to use a plastic substrate or the like having a lower heat resistance in the annealing process for achieving the same.

  Note that the laser processing apparatus 1 according to the first embodiment described above may have a configuration in which irradiation heads are arranged at intervals of laser light irradiation over a height direction parallel to the axis φ of the processing substrate W. With such a configuration, the irradiation head may be moved on a circular orbit maintained at each height of the axis φ. In this case, the laser light is turned on the entire surface of the processing surface Wa of the processing substrate W by turning each irradiation head relatively around the substrate support portion 11 and turning on / off the laser light in the meantime. The irradiation process can be completed.

Second Embodiment
FIG. 4 is a perspective view showing a schematic configuration of the laser processing apparatus of the second embodiment. The difference between the laser processing apparatus 2 of the second embodiment shown in this figure and the laser processing apparatus 1 described with reference to FIGS. 1 to 3 is the positional relationship between the substrate support portion 21 and the irradiation head.

  That is, the substrate support portion 21 in the laser processing apparatus 2 is configured as a cylindrical body, and the inner surface side of the cylindrical surface is configured as a support surface 21a, and other than this, the substrate support portion is the same as the substrate support portion of the first embodiment. is there. In other words, the support surface 21 a of the substrate support portion 21 is configured to hold the processing substrate W by suction. There is no particular limitation on the suction holding mechanism, and for example, an electrostatic suction method or a vacuum suction method may be used. The substrate support portion 21 is configured to be rotatable at a constant rotation speed v1 in one direction (here, counterclockwise) around the axis φ of the cylindrical surface formed by the support surface 21a. Further, the substrate support portion 21 may be configured to be movable at a constant speed in the axis φ direction of the cylindrical surface formed by the support surface 21a. In the drawing, in order to explain the support surface 21a, a part of the processing substrate W is notched.

  The irradiation heads 13-1, 13-2,... Are arranged so as to irradiate laser light toward the support surface 21a of the substrate support portion 21. The arrangement state, movement path, and speed of these irradiation heads 13-1, 13-2,... Are the same as those in the first embodiment.

  Laser processing using the laser processing apparatus 2 having such a configuration is performed in the same procedure as in the first embodiment. That is, first, the processing substrate W is sucked and held on the support surface 21 a on the inner surface side of the substrate support portion 21. At this time, the processing surface Wa of the processing substrate W is directed inward so that the inner surface side of the cylindrical surface becomes the processing surface Wa. Next, each irradiation is performed such that the uppermost irradiation head among the irradiation heads 13-1, 13-2,... Is disposed above the uppermost end of the processing substrate W supported by the substrate support unit 11. The heads 13-1, 13-2,... Are installed, and the irradiation heads 13-1, 13-2,... Move in a predetermined direction (downward here) on the spiral trajectory described in the first embodiment. Let it begin.

Then, the relative movement of the irradiation heads 13-1, 13-2,... Relative to the surface Wa to be processed on the spiral trajectory centering on the axis φ of the cylindrical surface as described above causes the object to be covered. The entire region of the processing surface Wa is scanned with the laser beam irradiated from the irradiation heads 13-1, 13-2,. At this time, while moving the irradiation position of the laser beam with respect to the surface Wa to be processed, the laser beam is irradiated only at a desired position by controlling ON / OFF of the laser beam. Further, after the irradiation head arranged at the lowermost part passes through a predetermined position at the lowermost end of the processing substrate W supported by the substrate support part 11, the irradiation heads 13-1, 13-2,. Stop moving.

  In the laser processing apparatus and laser processing method of the second embodiment described above, the irradiation heads 13-1, 13- are applied to the processing surface Wa of the processing substrate W arranged in the state of constituting the inner surface side of the cylindrical surface. The laser beam is scanned over the entire region of the surface Wa by moving the two,... In one relative direction. That is, the laser beam is continuously irradiated to the entire area of the processing surface Wa without changing the relative moving direction of the irradiation heads 13-1, 13-2,. Yes.

  Therefore, as in the first embodiment, it is possible to reduce the size of the apparatus that performs the process of moving the irradiation position of the laser beam at a constant speed with respect to the substrate. Then, the thermal load on the substrate W is performed by performing a process of irradiating only the desired position by controlling the ON / OFF of the laser beam while moving the irradiation position of the laser beam with respect to the processing surface Wa. For example, a plastic substrate with lower heat resistance can be used in the annealing process for crystallizing the semiconductor thin film on the substrate W, for example. .

  In the laser processing apparatus 2 according to the second embodiment described above, an irradiation head is arranged at every laser beam irradiation interval over a height direction parallel to the axis φ of the processing substrate W as in the first embodiment. It may be. With such a configuration, it is only necessary to move the irradiation heads on circular orbits maintained at the respective heights of the axis φ, and each irradiation head is relative to the substrate support portion 21 as in the first embodiment. Thus, the laser beam irradiation process can be completed for the entire region of the processing surface Wa of the processing substrate W.

<Third Embodiment>
FIG. 5 is a top view showing a schematic configuration of the laser processing apparatus of the third embodiment. The difference between the laser processing apparatus 3 of the third embodiment shown in this figure and the laser processing apparatus 3 of the second embodiment described with reference to FIG. 4 is that the configuration of the substrate support 31 and the present laser processing apparatus 3 are different. Is that a supply roll 33 and a take-up roll 35 for the processing substrate W are provided. FIG. 5 is a top view of the substrate support portion 31 configured as a cylindrical body as viewed from the cylindrical bottom surface side.

  That is, the substrate support portion 31 in the laser processing apparatus 3 is configured as a cylindrical body, and the inner surface side of the cylindrical surface is configured as the support surface 31a. In particular, the side wall of the substrate support portion 31 is provided with a slit 31b for inserting the processing substrate W into the support surface 31a formed on the inner surface side of the cylindrical surface. The slit 31b is provided in parallel with the axis φ of the cylindrical surface formed by the support surface 31a.

  The support surface 31a is configured to suck and hold the processing substrate W and to be slidable in the circumferential direction of the support surface 31a.

  And the supply roll 33 unwinds and supplies the process substrate W freely. On the other hand, the take-up roll 35 is for freely taking up and collecting the processing substrate W. Then, the processing substrate W supplied from the supply roll 33 is inserted into the substrate support portion 31 through the slit 31b and is sucked and held on the support surface 31a of the substrate support portion 31 and slides on the support surface 31a. And is wound around the winding roll 35.

  In addition, at the opening end of the slit 31b, the processing substrate W is fed from the supply roll 33 to the support surface 31a of the substrate support 31 and the processing substrate W is smoothly wound from the support surface 31a to the take-up roll 35. For this reason, it is assumed that a rotatable roller 37 is provided. Note that such a roller 37 may be arranged in an arrangement state as necessary.

  The irradiation heads 13-1, 13-2,... Are arranged so as to irradiate laser light toward the support surface 31a of the substrate support portion 31. The arrangement state and movement of these irradiation heads 13-1, 13-2,... Are the same as those in the first embodiment.

  Laser processing using the laser processing apparatus 3 having such a configuration is performed as follows.

  First, the processing substrate W supplied from the supply roll 33 is inserted into the substrate support portion 31 through the slit 31 b and sucked and held on the support surface 31 a of the substrate support portion 31. Further, the front end of the processing substrate W is led out from the slit 31 b and wound on the winding roll 35. At this time, the target surface Wa of the target substrate W attracted and held by the support substrate 31 is directed inward so that the inner surface side of the cylindrical surface becomes the target surface Wa.

  Next, each irradiation is performed such that the uppermost irradiation head among the irradiation heads 13-1, 13-2,... Is arranged above the uppermost end of the processing substrate W supported by the substrate support unit 31. The heads 13-1, 13-2,... Are installed, and the irradiation heads 13-1, 13-2,... Move in a predetermined direction (downward here) on the spiral trajectory described in the first embodiment. Let it begin. Then, the relative movement of the irradiation heads 13-1, 13-2,... Relative to the surface Wa to be processed on the spiral trajectory centering on the axis φ of the cylindrical surface as described above causes the object to be covered. The entire region of the processing surface Wa is scanned with the laser beam irradiated from the irradiation heads 13-1, 13-2,. At this time, while moving the irradiation position of the laser beam with respect to the surface Wa to be processed, the laser beam is irradiated only at a desired position by controlling ON / OFF of the laser beam. Further, after the irradiation head arranged at the lowermost portion passes through a predetermined position at the lowermost end of the processing substrate W supported by the substrate support portion 31, the irradiation heads 13-1, 13-2,. Stop moving.

  As described above, after performing the first process of irradiating the entire surface of the processing surface Wa portion of the processing substrate W held on the support surface 31 a of the substrate support portion 31 with the laser beam, from the supply roll 33. The substrate W to be unwound and fed and the substrate W to be wound around the take-up roll 35 are wound. Then, the unprocessed portion of the substrate W to be processed is attracted and held on the support surface 31 a of the substrate support portion 31.

  In this state, movement of the irradiation heads 13-1, 13-2,... On the spiral trajectory described in the first embodiment in a predetermined direction is started, and a second process is performed. At this time, if the irradiation heads 13-1, 13-2,... Have been returned to the processing start position, the irradiation heads 13-1, 13-2,. Let On the other hand, when the positions of the irradiation heads 13-1, 13-2,... Remain in the state where the first process is completed, the first process is performed on the spiral trajectory described in the first embodiment. The irradiation heads 13-1, 13-2,... Are moved in the opposite direction.

  After the second processing as described above is completed, the substrate W to be unwound and supplied from the supply roll 33 and the substrate W to be wound around the take-up roll 35 are again wound. The first process of irradiating the unprocessed portion of W with laser light is repeated.

  In the laser processing apparatus of the third embodiment, the moving speed of the processing substrate W due to the rotation of the supply roll 33, the winding roll 35, and the substrate support 31 and the irradiation heads 13-1, 13-2,. By appropriately combining these movement speeds, the continuous processing may be performed on the entire processing surface Wa while continuously moving the processing substrate W without stopping.

  Even in the laser processing apparatus and the laser processing method of the third embodiment described above, similarly to the second embodiment, the processing surface Wa of the processing substrate W arranged in a state of constituting the inner surface side of the cylindrical surface is applied. On the other hand, by moving the irradiation heads 13-1, 13-2,... In one relative direction, the entire region of the processing surface Wa is scanned with the laser light. Therefore, the same effects as those of the first embodiment and the second embodiment described above can be obtained.

  In the laser processing apparatus 3 of the third embodiment described above, the irradiation head is arranged at each laser beam irradiation interval over the height direction parallel to the axis φ of the processing substrate W as in the first embodiment. It may be. With such a configuration, it is only necessary to move the irradiation heads on circular orbits maintained at the respective heights of the axis φ, and each irradiation head is relative to the substrate support portion 31 as in the first embodiment. Thus, the laser light irradiation process can be completed for the entire area of the processing surface Wa portion of the processing substrate W supported by the substrate support portion 31. At this time, the processing substrate W is moved by the rotation of the supply roll 33, the winding roll 35, and the substrate support portion 31, thereby continuously moving the processing substrate W without stopping the movement of the processing substrate W. It becomes possible to perform processing on the entire surface.

<Fourth embodiment>
FIG. 6 is a top view showing a schematic configuration of the laser processing apparatus according to the fourth embodiment. The difference between the laser processing apparatus 4 of the fourth embodiment shown in this figure and the laser processing apparatus 3 of the third embodiment described with reference to FIG. FIG. 6 is a top view of the substrate support part 41 configured as a cylindrical body as viewed from the cylindrical bottom surface side.

  That is, the substrate support portion 41 in the laser processing apparatus 4 is configured as a cylindrical body, and the outer surface side of the cylindrical surface is configured as the support surface 41a. In particular, the substrate support portion 41 is characterized in that it is made of a material that transmits laser light, such as quartz.

  The support surface 41a sucks and holds the processing substrate W, and the processing substrate W is configured to be slidable in the circumferential direction of the support surface 41a.

  The laser processing apparatus 4 is also provided with a supply roll 43 for freely unwinding and supplying the processing substrate W and a winding roll 45 for freely winding and collecting the processing substrate W. The processing substrate W supplied from the supply roll 43 is configured to be sucked and held on the support surface 41a of the substrate support portion 41 and to be wound on the take-up roll 45 by sliding on the support surface 41a. . Note that a rotatable roller 47 for smooth movement of the processing substrate W is disposed between the supply roll 43 and the substrate support 41 and between the substrate support 41 and the take-up roll 45 as necessary. It is assumed that it is arranged at.

  The irradiation heads 13-1, 13-2,... Are arranged inside the cylindrical body of the substrate support portion 41, and are arranged so as to irradiate laser light toward the inner surface side of the cylindrical surface. Thereby, the laser beam irradiated from the irradiation heads 13-1, 13-2,... Passes through the wall portion of the substrate support portion 41 made of quartz or the like, and is a support surface 41a configured on the outer surface side of the cylindrical surface. It is the composition which is irradiated. It is assumed that the arrangement state, movement path, and speed of these irradiation heads 13-1, 13-2,... Are the same as those in the first embodiment.

  When performing laser processing using the laser processing apparatus 4 having such a configuration, first, the support surface 41a of the substrate support 41 is wound in a state where the processing substrate W supplied from the supply roll 43 is wound around the substrate support 41. To adsorb and hold. Further, the front end of the processing substrate W is wound around the winding roll 45. At this time, the target surface Wa of the target substrate W attracted and held by the support substrate 41 is set to be in a state of facing the support surface 41a.

  And the irradiation of the laser beam with respect to the process board | substrate W hold | maintained at the board | substrate support part 41 as mentioned above is performed like having demonstrated in 3rd Embodiment.

  Even in the laser processing apparatus and laser processing method of the fourth embodiment described above, similarly to the second embodiment, the processing surface Wa of the processing substrate W arranged in the state of constituting the inner surface side of the cylindrical surface is applied. On the other hand, by moving the irradiation heads 13-1, 13-2,... In one relative direction, the entire region of the processing surface Wa is scanned with the laser light. Therefore, the same effects as those of the first embodiment and the second embodiment described above can be obtained.

<Fifth Embodiment>
FIG. 7 is a perspective view showing a schematic configuration of the laser processing apparatus of the fifth embodiment. The laser processing apparatus 5 of the fifth embodiment shown in this figure is an apparatus having the roll-to-roll configuration of the laser processing apparatus 1 of the first embodiment described with reference to FIG.

  That is, the laser processing apparatus 5 includes a substrate support portion 51 made of a cylindrical body that is sufficiently longer than the width of the processing substrate W. And the outer surface side of the cylindrical surface of the substrate support portion 51 is a support surface 51a, and the processing substrate W is spirally wound around the support surface 51a. The substrate support portion 51 is configured to be rotatable at a constant rotational speed v1 in one direction (here, clockwise) around the axis φ of the cylindrical surface formed by the support surface 51a.

  The laser processing apparatus 5 is also provided with a supply roll 53 for freely unwinding and supplying the processing substrate W, and a winding roll 55 for freely winding and collecting the processing substrate W. The processing substrate W supplied from the supply roll 53 is spirally wound around the support surface 51 a of the substrate support portion 51 by the rotation of the substrate support portion 51, and the tip thereof is wound around the take-up roll 45. It has become. Although illustration is omitted here, supply and winding of the processing substrate W to and from the substrate support 51 between the supply roll 53 and the substrate support 51 and between the substrate support 51 and the take-up roll 55 are performed. It is assumed that a rotatable roller for smoothing out is arranged in an arrangement state as necessary.

  The irradiation heads 13-1, 13-2,... Are arranged on the support surface 51a of the substrate support portion 51 on the outer side of the cylindrical body, and are arranged so as to irradiate the laser beam toward the outer surface side of the cylindrical surface. ing. Each of the irradiation heads 13-1, 13-2,... Is arranged at a position kept at an equal distance with respect to the axis φ of the cylindrical surface formed by the support surface 51a. Further, each of the irradiation heads 13-1, 13-2,... Is arranged corresponding to each height position of the axis φ. In the figure, only four irradiation heads 13-1, 13-2,... Are shown, but these irradiation heads 13-1, 13-2,. It is assumed that a plurality of the processing surfaces 51 of the processing substrate 51 moving in a spiral shape are arranged in such a manner that the laser light is irradiated.

  When performing laser processing using the laser processing apparatus 5 having such a configuration, first, the processing substrate W supplied from the supply roll 43 is spirally wound around the substrate support portion 51, and further, the tip is wound. It is wound around a roll 55. At this time, the processing surface Wa of the processing target substrate W wound around the support substrate 51 is set to a state facing outward.

  In this state, the take-up roll 55, the substrate support 51, and the supply roll 53 are rotated while adjusting the rotation speed, and the processing substrate W wound around the substrate support 51 is rotated and moved in a spiral manner. Further, the irradiation heads 13-1, 13-2,... Are rotated about the axis φ in the direction opposite to the rotation of the substrate support portion 51. In this state, while moving the irradiation position of the laser beam with respect to the processing surface Wa of the processing substrate W wound around the substrate support portion 51, the laser beam is controlled only on a desired position by controlling ON / OFF of the laser beam. Irradiate with light.

  Even in the laser processing apparatus and laser processing method of the fifth embodiment described above, similarly to the second embodiment, the processing surface Wa of the processing substrate W arranged in the state of constituting the inner surface side of the cylindrical surface is applied. On the other hand, by moving the irradiation heads 13-1, 13-2,... In one relative direction, the entire region of the processing surface Wa is scanned with the laser light. Therefore, the same effects as those of the first embodiment and the second embodiment described above can be obtained.

<Laser irradiation mechanism>
Next, an example of the laser irradiation mechanism provided in each irradiation head in the laser processing apparatus of each embodiment described above will be described with reference to FIG. In the following, a configuration in which the laser irradiation mechanism 10 of the laser processing apparatus 1 of the first embodiment is provided will be described on behalf of each embodiment, but the laser processing apparatuses of the second embodiment and the third embodiment will be described. The same applies to.

  FIG. 8 is a configuration diagram showing irradiation heads 13-1, 13-2,... (Denoted as irradiation heads 13) and a laser irradiation mechanism 10 for controlling the driving of each irradiation head 13. The laser irradiation mechanism 10 shown in this figure is a mechanism for controlling the irradiation position and depth of focus of the laser beam from the irradiation head 13 with respect to the processing surface Wa of the processing substrate W supported by the substrate support portion 11. is there.

  First, before describing the configuration of the laser irradiation mechanism 10, the configuration of each irradiation head 13 will be described. Each irradiation head 13 includes a light source unit 102 and an objective lens 103 arranged to face the support surface 11 a of the substrate support unit 11. In the drawing, the support surface 11a of the substrate support 11 is shown in a flat stage shape. As described in the first embodiment, the substrate support 11 is a cylindrical body (or a cylindrical body). The outer surface side of the cylindrical surface is configured as a support surface 11a.

  Among these, the light source unit 102 is provided with a semiconductor laser oscillator 102a. As the semiconductor laser oscillator 102a, one that oscillates laser light Lh having an appropriate wavelength is selected depending on what kind of processing is performed using this laser processing apparatus. For example, when this laser processing apparatus is used for crystallization and activation of a semiconductor thin film made of amorphous silicon, a compound semiconductor laser including Ga and N having an oscillation wavelength of 350 nm to 470 nm is used. In particular, a GaN-based compound semiconductor laser oscillator having a high power necessary for crystallization and activation (for example, a rating of 40 mW or more by continuous irradiation) is preferably used.

  The light source unit 102 includes a plurality of members arranged on the optical path of the laser beam Lh oscillated from the semiconductor laser oscillator 102a, and the method is applied to the surface of the substrate W arranged on the substrate support unit 11. The laser beam Lh is irradiated from the linear direction. The configuration of the light source unit 102 will be described along the optical path order of the laser light Lh.

  That is, the laser beam Lh oscillated from the semiconductor laser oscillator 102a spreads with a large spread angle. For this reason, a collimator lens 102b having a large numerical aperture NA is disposed at the subsequent stage of the semiconductor laser oscillator 102a, and the laser light Lh is incident on the collimator lens 102b to be parallel light. Further, the laser light Lh oscillated from the semiconductor laser oscillator 102a has different divergence angles between the crystal growth direction of the semiconductor laser and the direction parallel to the crystal growth direction, so that the beam shape is elliptical while being collimated by the collimator lens 102b. It has become. For this reason, an anamorphic prism 102c in which two prisms are combined is disposed at the subsequent stage of the collimator lens 102b, and the laser light Lh is incident on the anamorphic prism 102c and the beam shape is converted into a circular beam.

A polarizing beam splitter 102d designed to have a P-wave transmittance T _p = 100% and an S-wave reflectance R _s = 100% is disposed downstream of the anamorphic prism 102c. Here, when a plane parallel to the paper surface is used as a refracting surface, the orientation of the laser light Lh oscillated from the semiconductor laser oscillator 102a is previously set so as to be polarized in a direction parallel to the paper surface. . Thereby, the laser beam Lh (for example, wavelength 405 nm) converted into a circular beam is configured to pass through the polarization beam splitter 102d.

  A λ / 4 plate 102e is disposed at the subsequent stage of the polarization beam splitter 102d, and the laser light Lh becomes circularly polarized light by passing through the λ / 4 plate 102e. Further, a dichroic prism 102f is arranged at the subsequent stage of the λ / 4 plate 102e, and the dichroic prism 102f is used to process the surface Wa of the processing substrate W disposed on the support surface 11a of the substrate support portion 11. The laser beam Lh is irradiated from the normal direction.

  The laser beam Lh reflected by the processing surface Wa is further reflected by the dichroic prism 102f and is incident on the λ / 4 plate 102e. The λ / 4 plate 102e becomes linearly polarized light orthogonal to the incident time, is reflected by the polarization beam splitter 102d, and is absorbed by the beam damper 102g. By such an optical path, the light returning to the semiconductor laser oscillator 102a can be minimized, and the laser oscillation is kept stable.

  The objective lens 103 disposed between the light source unit 102 and the substrate support unit 11 configured as described above is irradiated with the laser beam Lh from the light source unit 102 toward the support surface 11a of the substrate support unit 11. It is arranged on the optical path.

  The objective lens 103 is preferably made of glass or resin, and is preferably corrected for chromatic aberration with respect to laser light Lh (for example, wavelength 405 nm) and inspection light (for example, wavelength 830 nm) described below.

  In particular, the objective lens 103 is provided in a state of being mounted on a biaxial actuator not shown here. Accordingly, the objective lens 103 is configured to move in two axial directions, that is, a lens axis (optical axis) direction and a direction perpendicular to the lens axis (optical axis) direction by a drive signal from the outside of the scanning control unit 104 described below. The biaxial actuator may be a voice coil, a piezo actuator, or the like, and its form is not limited.

  The laser irradiation mechanism 10 for controlling the irradiation head 13 composed of the light source unit 102 and the objective lens 103 as described above is for scanning the laser beam Lh while being connected to the objective lens 103. Scanning controller 104 is provided. Further, the laser irradiation mechanism 10 includes an inspection light source unit 106, a focus control unit 107, and a position control unit 108 for irradiating the inspection light fh.

  The scanning control unit 104 provided in the objective lens 103 is provided as a biaxial device driver (scanning control unit) 104 that controls driving of the biaxial actuator on which the objective lens 103 is mounted. The biaxial device driver (scanning control unit) 104 also serves as a part of a focus control unit 107 and a position control unit 108 described below.

  Here, the laser light Lh incident on the objective lens 103 is collimated light, and the beam shape at the focal point is represented by a sinc function. When the numerical aperture NA of the objective lens 103 and the wavelength λ of the laser light Lh are set, the beam diameter (the diameter of the smallest circle with an amplitude of 0) φ is expressed by the following equation (1). φ = 2.44 × λ / (2 × NA) (1)

  In such laser light Lh, the intensity in the direction perpendicular to the optical axis (lens axis) has a Gaussian distribution. For this reason, the movement of the objective lens 103 in the direction perpendicular to the optical axis by the biaxial device driver (scanning control unit) 104 is performed in a range where the power density at the focal point formed by the objective lens 103 changes within 5%. It is assumed that it is set as follows. Thereby, when the laser beam Lh is scanned by moving the objective lens 103, a change in the irradiation intensity of the laser beam Lh at each scanning position can be suppressed to be small. As an example, when the objective lens 103 having a numerical aperture NA of 0.85 is used, the objective lens 103 is moved so that the laser light Lh is incident within a range of ± 50 μm from the lens axis (center position) of the objective lens 103. Thus, the change in power density at the focal point formed by the objective lens 103 can be suppressed to 5% or less. It is preferable that the intensity distribution of the laser beam Lh and the size of the aperture of the objective lens are designed so that the scanning range of the laser beam Lh due to the movement of the objective lens 103 is expanded as much as possible.

  Next, the inspection light source unit 106 is provided with an inspection light oscillator 106a that oscillates the inspection light fh. Here, as the inspection light fh, light having a wavelength that is not absorbed by the material to be processed is used. For this reason, for example, when a laser processing apparatus is used for crystallization and activation of a semiconductor thin film made of amorphous silicon, a laser having a wavelength of 650 nm or more, preferably a wavelength of 830 nm, in which absorption in the silicon-based semiconductor film becomes small. Light is used as inspection light fh. Thereby, the influence on the substrate W surface by the irradiation of the inspection light fh is prevented. As the inspection light source unit 106 that oscillates such inspection light fh, for example, a laser oscillator that oscillates laser light having a wavelength of 830 nm as inspection light fh is used.

  The inspection light source unit 106 includes a plurality of members arranged on the optical path of the inspection light fh oscillated from the inspection light oscillator 106a. The inspection light source unit 106 is mounted on the substrate support unit 11 through the objective lens 103 together with the laser light Lh described above. It is comprised so that the surface of the board | substrate W arrange | positioned may be irradiated. Such a configuration of the inspection light source unit 106 is substantially the same as the configuration of the light source unit 102 of the irradiation head 13 described above.

In other words, the inspection light fh oscillated from the inspection light oscillator 106a is incident on the collimator lens 106b to be parallel light, and is incident on the anamorphic prism b to be converted into a circular beam. The inspection light fh is transmitted through the polarization beam splitter 106d designed to have a P-wave transmittance T _p = 100% and an S-wave reflectance R _s = 100%, and passes through the λ / 4 plate 106e. It passes through and becomes circularly polarized light. Then, the light passes through the dichroic prism 102 f in the light source unit 102 of the irradiation head 13, is combined with the laser light Lh, and enters the objective lens 103.

  The inspection light fh reflected by the substrate W passes through the dichroic prism 102f and enters the λ / 4 plate 106e. The λ / 4 plate 106e becomes linearly polarized light orthogonal to the incident time, is reflected by the polarization beam splitter 106d, and is guided to the focus control unit 107 and the position control unit 108.

  Then, the cylindrical lens 107a, the condensing lens 107b, and the quadrant detector 107c are arranged in this order in the focus control unit 107 to which the inspection light fh reflected by the polarization beam splitter 106d is guided in the traveling direction of the inspection light fh. Has been placed.

  The cylindrical lens 107a is for generating astigmatism. The quadrant detector 107c is in an imaging relationship with the substrate W disposed on the substrate support 11 as a processing object. Therefore, when the objective lens 103 is focused on the substrate W, the inspection light fh is focused at the center of the quadrant detector 107c. On the other hand, when the focus of the objective lens 103 is above or below the surface of the substrate W, astigmatism occurs due to the cylindrical lens 107a, and the longitudinal axis or the horizontal direction has a long axis on the quadrant detector 107c. An elliptical beam is projected.

  Therefore, when the output signals A to D from the respective detector portions of the quadrant detector 107c are defined as described below, the signal (A + C) − (B + D) indicates whether the focus of the objective lens 103 is above or below the object. Change the sign of plus and minus, and this signal becomes zero when the focus is on the object. Therefore, this signal is used as an error signal (focus error signal) when focus servo is performed, and this error signal is fed back to the scanning control unit 104 of the objective lens 103 so that the signal becomes zero. Is moved in the lens axis direction (vertical direction in the drawing) to perform focus servo.

  The position control unit 108 to which the inspection light fh reflected by the polarization beam splitter 106d is guided is provided with the focus control unit 107 and the image signal position recognition unit 108a in the traveling direction of the inspection light fh. Arranged in order. Here, it is assumed that the focus control unit 107 also serves as a part of the position control unit 108.

  Then, the image signal position recognition unit 108a provided at the subsequent stage of the focus control unit 107 is based on the information on the surface of the substrate W to be processed and the output signals A to D from each detector portion of the quadrant detector 107c. Thus, the position where the inspection light fh is irradiated through the objective lens 103 is recognized.

  That is, when the output signals A to D from the respective detector portions of the quadrant detector 107c are defined, the sum signal (A + B + C + D) is a signal indicating a change in the reflectance of the exposure target. Therefore, an alignment mark serving as the same reference point in a two-dimensional plane on the processing surface Wa on the processing substrate W is formed in a pattern. Then, in the image signal position recognition unit 108a, the processing substrate W is obtained by the shape information (alignment mark arrangement information) of the surface of the substrate W obtained in advance and the relative movement between the irradiation head 13 and the substrate support unit 11. The irradiation position of the inspection light fh on the processing surface Wa is recognized from the change of the sum signal obtained by scanning the inspection surface fh on the processing surface Wa.

  In this laser processing apparatus, a reference point for annealing using the laser processing apparatus is obtained from the irradiation position of the inspection light fh recognized by the image signal position recognition unit 108a. Then, the arrangement state of the processing substrate W in the laser processing apparatus is set to a predetermined state by relatively moving the irradiation head 13 and the substrate support portion 11 based on the reference point. That is, the irradiation head 13 and the substrate support part 11 are relatively moved so that the portion on the surface of the irradiation substrate W to be annealed is the irradiation position of the laser light Lh.

  Further, the position control unit 108 moves from the semiconductor laser oscillator 102a in a state where the substrate support unit 11 and the irradiation head 13 are relatively moved so that the laser beam Lh is at a predetermined irradiation position as described above. By controlling on / off of the oscillation of the laser beam Lh, the laser beam Lh is irradiated only on the target portion of the processing surface Wa of the processing substrate W. Furthermore, the laser with respect to the processing surface Wa of the processing substrate W placed on the substrate support 11 is obtained by moving the objective lens 103 in a direction perpendicular to the axis by the biaxial device driver (scanning control unit) 104. The irradiation position of the light Lh may be controlled with high accuracy.

  In the above laser processing apparatus, the movement (scanning) of the irradiation position of the laser beam Lh by driving the substrate support 11 and the irradiation head 13 and the scanning of the laser beam Lh by the movement of the objective lens 103 may be combined. good. When the scanning of the laser beam Lh by the movement of the objective lens 103 is combined, the processing substrate W can be scanned with the laser beam Lh at a high speed. As a result, an annealing process that reduces the thermal load on the processing substrate W can be performed by the moving speed of the laser light Lh relative to the processing substrate W. Further, by selectively performing such irradiation of the laser beam Lh only on a necessary portion with respect to the processing substrate W, the thermal load on the processing substrate W is further reduced.

  Further, by adjusting the intensity of the laser beam Lh by adjusting the output of the laser beam Lh oscillated from the semiconductor laser oscillator 102a and changing the duty in the case of AC driving, an arbitrary laser intensity can be placed in the XY two-dimensional region on the substrate. It is also possible to form a distribution pattern.

  In addition, the provision of the semiconductor laser oscillator 102a makes it possible to reduce the size of the entire apparatus by reducing the size of the irradiation head 13-1 as compared with an excimer laser apparatus or a YAG laser. Further, since the irradiation head 13-1 is downsized, a plurality of laser irradiation mechanisms 10 including the irradiation head 13-1 may be provided to irradiate laser beams at multiple points on each position of the substrate W. . Thereby, it becomes possible to shorten the process of laser irradiation and improve productivity.

  When this laser processing apparatus is used for crystallization and activation of a semiconductor thin film made of amorphous silicon, the continuous irradiation of the laser beam Lh onto the substrate W is completely continuous without any interruption during the movement of the laser beam Lh. And a case where there is a pause that does not completely complete solidification of the melted semiconductor thin film portion by irradiation with the laser beam Lh. For this reason, if such a condition is satisfied, the case where a pause time shorter than the irradiation time is included is included in the continuous irradiation. As an example, a pause of about 10 to 20 ns is included with respect to the irradiation time of 100 ns to the semiconductor thin film portion. In some cases, it is included in continuous irradiation. Note that the pause time with respect to the irradiation time is appropriately designed according to the material and thickness of the semiconductor thin film, the energy density of the laser light Lh, and the like. By providing such a pause time, the thermal influence on the substrate W due to the laser light Lh irradiation can be suppressed. The excimer laser light is a complete pulse wave, and if it is a pulse wave of about 300 Hz, a pause of about 3300 ns will occur for an irradiation time of 25 ns. For this reason, in the excimer laser light, the next pulse irradiation is performed in a state where the solidification of the melted semiconductor thin film 5 portion by the irradiation of the laser light Lh is completed. Can not.

It is a perspective view for demonstrating the structure of the laser processing apparatus of 1st Embodiment. It is a side view for demonstrating an example of the relative movement of the irradiation head in the laser processing apparatus of 1st Embodiment. It is a side view for demonstrating another example of the relative movement of the irradiation head in the laser processing apparatus of 1st Embodiment. It is a perspective view for demonstrating the structure of the laser processing apparatus of 2nd Embodiment. It is a top view for demonstrating the structure of the laser processing apparatus of 3rd Embodiment. It is a top view for demonstrating the structure of the laser processing apparatus of 4th Embodiment. It is a perspective view for demonstrating the structure of the laser processing apparatus of 5th Embodiment. It is a block diagram of the laser irradiation mechanism used suitably for the laser processing apparatus of each embodiment.

Explanation of symbols

1, 2, 3, 4, 5... Laser processing apparatus, 11, 21, 31, 41, 51... Substrate support part, 11a, 21a, 31a, 41a, 51a ... support surface, 13-1, 13-2,. Irradiation head, 31b ... slit, 33, 43, 53 ... supply roll, 35, 45, 55 ... take-up roll, W ... treated substrate, φ ... axis

Claims (8)

A substrate support portion in which the outer surface side or the inner surface side of the cylindrical surface is configured as a support surface of the processing substrate;
An irradiation head for irradiating the processing substrate supported by the support surface of the substrate support unit with laser light;
With respect to the entire region of the processing substrate supported on the support surface by the movement of the irradiation head relative to the support surface in one direction on the track centering on the axis of the cylindrical surface constituting the support surface. A laser processing apparatus, wherein the irradiation head is scanned. The laser processing apparatus according to claim 1,
The laser processing apparatus, wherein the irradiation head moves in a predetermined direction on a spiral orbit centering on an axis of a cylindrical surface constituting the support surface. The laser processing apparatus according to claim 2,
The laser processing apparatus, wherein the substrate support section rotates in the direction opposite to the moving direction of the irradiation head around an axis of a cylindrical surface constituting the support surface. The laser processing apparatus according to claim 1,
A plurality of the irradiation heads are arranged at predetermined intervals along an axis of a cylindrical surface constituting the support surface. The laser processing apparatus according to claim 1,
The said substrate support part is equipped with the mechanism by which the said process substrate is adsorbed-held with respect to the said support surface. The laser processing apparatus characterized by the above-mentioned. The laser processing apparatus according to claim 1,
A supply roll for unwinding and supplying the processing substrate to the support surface of the substrate support part;
A laser processing apparatus, further comprising: a winding roll that winds and collects the processing substrate from a support surface of the substrate support portion. The laser processing apparatus according to claim 1,
The irradiation head is configured by using a semiconductor laser oscillator. A laser processing method for performing processing by laser light irradiation on the entire surface of the processing surface by irradiating the processing surface of the substrate while relatively scanning the laser light,
Install the processing substrate so that the outer surface side or inner surface side of the cylindrical surface is the surface to be processed,
Next, when irradiating a laser beam from the irradiation head toward the processing surface of the processing substrate, the irradiation head with respect to the processing surface on the trajectory around the axis of the cylindrical surface constituting the processing surface. A laser processing method, wherein the laser beam irradiated from the irradiation head is scanned over the entire area of the surface to be processed by movement in one relative direction.

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