JP2009297742A - Laser processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser processing apparatus where a plurality of laser beams with thin and long shape in the cross-sectional face can be simultaneously produced from one laser beam in a simple constitution, and its production cost is reduced. <P>SOLUTION: The laser processing apparatus includes: a stage 1 reciprocately carrying a rectangular substrate 5; a laser head 2 provided so as to be confronted with the upper face of the stage 1 and provided with a plurality of cylindrical lenses 18 producing a plurality of laser beams with thin and long shape in the cross-sectional face from laser beam radiated from a laser light source 14 and emitting them to a substrate 5; first and second imaging means 3A, 3B arranged so as to image the positions on this side in the carrying direction of the laser beam emission positions by the plurality of cylindrical lenses 18; and a control means 4 controlling the emission timing of the laser beam radiated from the laser light source 14 and the emission positions of the laser beams based on the images by the first and second imaging means 3A, 3B. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a laser processing apparatus that performs laser processing by irradiating a substrate with a laser beam from a laser light source while transporting the substrate in a certain direction by a transport means. The present invention relates to a laser processing apparatus capable of simultaneously generating a fine laser beam and reducing the manufacturing cost of the apparatus.

A conventional laser processing apparatus includes a mounting table that holds a substrate on which a film body is formed and moves in the X-axis direction and the Y-axis direction, a laser oscillator that emits laser light for laser processing the film body, and the laser oscillator A scanning mechanism that scans the laser beam emitted from the film body and an image processing sensor that measures the position of the laser-processed processing mark. The position of the processing mark is measured by the image processing sensor and the X of the processing mark is measured. The amount of undulation in the axial and Y-axis directions is detected, the direction and distance in which the amount of undulation is to be corrected is calculated, and the mounting table is moved to perform laser processing (see, for example, Patent Document 1).
JP 2004-170455 A

  However, in such a conventional laser processing apparatus, the scanning mechanism uses a galvano mirror or an acousto-optic element, and a control means for driving and controlling the scanning mechanism is required in addition to the control means for driving and controlling the apparatus. Thus, there is a problem that the configuration of the apparatus becomes complicated. In particular, in order to simultaneously form a plurality of processing patterns from a single laser light source, a plurality of the scanning mechanisms are required, and there is a problem that the configuration of the apparatus becomes more complicated. Further, since the galvanometer mirror and the acousto-optic element are expensive parts, there is a risk that a laser processing apparatus equipped with a plurality of these parts may have a high manufacturing cost due to a complicated apparatus configuration.

  Accordingly, the present invention addresses such problems, enables a laser beam having a simple configuration to simultaneously generate a plurality of thin cross-section laser beams from a single laser light source, and reduces the manufacturing cost of the apparatus. An object is to provide an apparatus.

  In order to achieve the above object, a laser processing apparatus according to the present invention is a laser processing apparatus that performs laser processing by irradiating a laser beam from a laser light source onto a substrate while holding the substrate by a transfer means and transferring the substrate in a certain direction. A laser head provided with a plurality of cylindrical lenses for generating a plurality of laser beams having a thin cross-sectional shape from laser light emitted from the laser light source and irradiating the substrate, and a laser beam by the plurality of cylindrical lenses An imaging unit arranged to image a position on the near side in the transport direction of the irradiation position, an irradiation timing of the laser light emitted from the laser light source based on an image captured by the imaging unit, and an irradiation position of the laser beam Control means for controlling.

  With such a configuration, while the substrate is held by the transport unit and transported in a certain direction, the imaging unit images the position of the laser beam irradiation position on the near side in the transport direction by the plurality of cylindrical lenses of the laser head, and the control unit Control the irradiation timing and position of the laser beam emitted from the laser light source based on the image picked up by the imaging means, and generate a plurality of laser beams having a cross-sectional shape from the laser beam using a plurality of cylindrical lenses. Irradiate the substrate and laser process.

  The laser head has a predetermined pitch so that the long axes of the plurality of cylindrical lenses are substantially parallel to the axis in the substrate transport direction within a plane parallel to the substrate holding surface of the transport means. A lens array arranged side by side is provided. Thus, a lens array in which a plurality of cylindrical lenses are arranged at a predetermined pitch so that the major axis thereof is substantially parallel to the axis in the substrate transport direction within a plane parallel to the substrate holding surface of the transport means. A plurality of laser beams having a thin cross-sectional shape substantially parallel to an axis in the substrate transport direction are generated by the provided laser head and irradiated onto the substrate.

  Further, the lens array is formed so as to be movable in a direction orthogonal to the transport direction of the substrate relative to the transport means. As a result, the lens array is moved relative to the transport means in a direction perpendicular to the transport direction of the substrate to perform laser processing.

  The substrate has a rectangular shape, and the laser head includes a first lens pair in which two cylindrical lenses are arranged at a predetermined interval parallel to the substrate transport direction, and the substrate transport direction. And a second lens pair in which two cylindrical lenses are arranged at a predetermined interval perpendicularly to each other and spaced apart by a predetermined distance in the substrate transport direction. Accordingly, a first lens pair in which two cylindrical lenses are arranged at a predetermined interval parallel to the substrate transport direction, and a second lens pair in which two cylindrical lenses are disposed at a predetermined interval orthogonal to the substrate transport direction. A plurality of laser beams having a thin cross-sectional shape are generated by a laser head that is spaced apart by a predetermined distance in the substrate transport direction and irradiated onto a rectangular substrate.

  Further, the first and second lens pairs are formed so as to be rotatable so that the irradiation position of the laser beam from each cylindrical lens is parallel to the edge of the rectangular substrate to be conveyed. . Thus, the first and second lens pairs are rotated so that the irradiation position of the laser beam from each cylindrical lens is parallel to the edge of the rectangular substrate to be conveyed.

  Furthermore, in the first and second lens pairs, the distance between the two cylindrical lenses is variably formed. Thereby, the interval between the two cylindrical lenses of the first and second lens pairs is changed to make the interval between the edge of the rectangular substrate and the laser irradiation position constant.

  And the said board | substrate is a board | substrate of a solar cell. Thereby, a plurality of laser processings are simultaneously performed on the surface of the solar cell with a plurality of laser beams.

  According to the first aspect of the present invention, it is possible to simultaneously generate a plurality of laser beams having a thin cross-sectional shape from one laser light source with an extremely simple configuration in which a plurality of cylindrical lenses are combined. Therefore, the configuration of the apparatus is simplified, and the manufacturing cost of the apparatus can be reduced. Also, the position of the laser beam irradiation position by the cylindrical lens on the front side in the conveyance direction is imaged, and the irradiation timing of the laser beam and the irradiation position of the laser beam emitted from the laser light source are controlled based on the captured image. For example, if the edge of the substrate transport direction is detected to control the irradiation timing of the laser beam, and the edge parallel to the substrate transport direction is detected to control the irradiation position of the laser beam, the periphery of the substrate Laser processing can be accurately performed at a position within a predetermined distance from the portion.

  According to the second aspect of the present invention, it is possible to simultaneously generate a plurality of laser beams having a thin cross-sectional shape parallel to the substrate transport direction. Therefore, a plurality of grooves can be laser processed in parallel to the substrate transport direction. Therefore, it is effective for forming a scribe line of a thin film type solar cell, for example.

  According to the third aspect of the invention, it is possible to perform laser processing by positioning with reference to the edge of the groove that has been previously laser processed. Therefore, a plurality of grooves can be formed in parallel with each other at a predetermined interval.

  According to the fourth aspect of the present invention, the groove can be laser-processed in a well shape on the surface of the rectangular substrate only by transporting the substrate in one direction. Therefore, for example, it is effective for forming a scribe line for a crystalline silicon solar cell.

  Furthermore, according to the invention which concerns on Claim 5, a groove | channel can be laser-processed in parallel with the peripheral part of a square-shaped board | substrate. Therefore, for example, the front electrode and the back electrode of a crystalline silicon solar cell can be reliably separated.

  Furthermore, according to the invention which concerns on Claim 6, even if the size of a board | substrate changes, the space | interval of the edge part of a square-shaped board | substrate and a laser irradiation position can be made constant.

  And according to the invention which concerns on Claim 7, the formation precision of the scribe line of a solar cell can be improved. Therefore, a solar cell with a high photoelectric conversion rate can be manufactured by expanding the light receiving region.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a schematic configuration diagram showing a first embodiment of a laser processing apparatus according to the present invention. The laser processing apparatus performs laser processing by irradiating a substrate with a laser beam from a laser light source while placing the substrate on a stage and transporting the substrate in a fixed direction. The stage 1, the laser head 2, and the first The second imaging means 3A and 3B and the control means 4 are provided. In the following description, the case where the substrate 5 is a solar cell 6 will be described.

  This solar cell 6 is a thin film type solar cell as shown in FIGS. 2 and 3, and as shown in FIG. 3A, a transparent electrode layer 7 and a photoelectric conversion layer are formed on a rectangular transparent substrate 5. 8, the back electrode layer 9 is formed in order, and the first separation groove 10 for separating the transparent electrode layer 7 and the transparent electrode layer 7 are connected to the back electrode layer 9 as shown in FIG. For this purpose, a contact line 11 and a second separation groove 12 for separating the back electrode layer 9 are arranged in parallel at a predetermined interval. In this case, a region A shown in FIG. 5B is a portion that does not contribute to photoelectric conversion, and it is desired to increase the photoelectric conversion efficiency by narrowing the width of the region A and widening the width of the light receiving region B. Yes. In FIG. 2 and FIG. 3B, reference numeral 13 denotes an electrode for extracting a current to the outside. L1 is the distance from the edge 5a, 5b orthogonal to the axis of the substrate 5 in the conveyance direction to the end of the laser processing groove, and L2, L3, L4 are respectively on the axis of the substrate 5 in the conveyance direction. This is the distance from the parallel edge 5 c to the edges of the first first separation groove 10, the contact line 11, and the second separation groove 12. L5 is the arrangement pitch of the first separation groove 10, the contact line 11, and the second separation groove 12.

  The stage 1 holds the substrate 5 of the solar cell 6 on the upper surface (substrate holding surface) and reciprocates and conveys the substrate 5 in one direction. The stage 1 serves as a conveying means, and the X axis shown in FIG. It moves in the Y-axis direction from the front side to the back side in the direction and the figure. The stage 1 is provided with an X, Y position sensor and a speed sensor (not shown), and the movement distance and movement speed of the stage 1 can be detected based on the output of each sensor.

  A laser head 2 is provided above the stage 1. The laser head 2 irradiates a substrate 5 with a laser beam and performs laser processing. The laser head 2 is a laser light source 14, a beam expander 15, a uniformizing means 16, a condenser lens 17, and a plurality of cylindrical lenses 18. It is configured with. In FIG. 1, reference numeral 19 denotes a reflecting mirror.

  Here, the laser light source 14 emits laser light, and a pulse laser that intermittently emits laser light having a wavelength of 1064 nm and energy of about 1200 mJ and laser light having a wavelength of 532 nm and energy of about 600 mJ at a period of 50 Hz. It is. The beam expander 15 emits the laser beam emitted from the laser light source 14 with an enlarged diameter. Further, the homogenizing means 16 is a unit that multi-reflects and uniformizes and emits laser light having an enlarged diameter, and is, for example, a rod lens or a light pipe. Furthermore, the condenser lens 17 emits the uniformed laser light as parallel light parallel to the optical axis, and is a condensing lens, and its front focal point is substantially matched with the exit side end face 16a of the uniformizing means 16. Are arranged. The plurality of cylindrical lenses 18 receive the parallel light and generate and output a thin laser beam having a cross section of, for example, 20 μm × 60 mm. As shown in FIG. 4, for example, 10 mm (W). The lens array 20 is formed in a shape of × 60 mm (L6), and the major axis is arranged in parallel with the axis in the transport direction of the substrate 5 in a plane parallel to the upper surface of the stage 1, for example, at a pitch of 10 mm. It is composed. FIG. 4 shows a lens array 20 in which eight cylindrical lenses 18 are arranged in parallel as an example.

  As shown in FIG. 1, the first and second imaging means 3A and 3B are separated from the center of the lens array 20 by a distance D1 before and after the laser head 2 in the transport direction. Is provided. The first and second imaging means 3A and 3B are for imaging the position of the laser beam irradiation position on the front side in the transport direction by the lens array 20, and the surface of the substrate 5 is parallel to the upper surface of the stage 1. It is a line camera in which a plurality of light receiving elements are arranged in a straight line in a direction substantially orthogonal to the transport direction, and detects the edge of the substrate 5 and the edge of a groove that has already been laser processed. When the substrate 5 is conveyed from right to left in FIG. 1, the first imaging unit 3A images the substrate 5, and when the substrate 5 is conveyed from left to right, the second imaging unit 3B 5 is switched to be used for imaging. Note that the positions of the first and second imaging means 3A and 3B corresponding to the first cylindrical lens 18a (see FIG. 4) of the lens array 20 are stored in advance in a memory 23 described later as a reference position. .

  A control unit 4 is provided by connecting to the stage 1, the laser light source 14, the lens array 20, and the first and second imaging units 3A and 3B. The control means 4 controls the irradiation timing and the irradiation position of the laser beam emitted from the laser light source 14 based on the images taken by the first and second imaging means 3A and 3B, as shown in FIG. As shown, the image processing unit 21, the calculation unit 22, the memory 23, the stage drive controller 24, the laser light source drive controller 25, and the control unit 26 are provided.

  Here, the image processing unit 21 detects the positions of the edge of the substrate 5 and the edge of the laser-processed groove based on the one-dimensional images picked up by the first and second image pickup means 3A and 3B. As shown in FIG. 6, an input switching unit 27, a buffer memory 28, a first position detecting unit 29, and a second position detecting unit 30 are provided. The input switching unit 27 switches between the input from the first imaging unit 3A and the input from the second imaging unit 3B. Further, a buffer memory 28 is provided in connection with the input switching unit 27. The buffer memory 28 temporarily stores a one-dimensional image picked up by the image pickup means 3. Further, a first position detector 29 is provided in connection with the buffer memory 28. The first position detection unit 29 sequentially reads out the one-dimensional images picked up by the first and second image pickup means 3A and 3B from the buffer memory 28, interpolates the pixels in the transport direction, and starts from the sudden change position of the luminance change. The position of the edge parts 5a and 5b (refer FIG. 2) orthogonal to the conveyance direction of the board | substrate 5 is detected. Then, the second position detection unit 30 interpolates the one-dimensional images picked up by the first and second image pickup means 3A and 3B in the direction in which the light receiving elements are arranged, and determines the substrate 5 from the sudden change position of the luminance change. The position of the edge 5c (see FIG. 2) parallel to the conveying direction and the edge of the laser processed groove, that is, the first separation groove 10, the contact line 11, and the second separation groove 12 are detected.

  In addition, the calculation unit 22 calculates the distance that the substrate 5 moves after detecting the edge portions 5a and 5b orthogonal to the transport direction of the substrate 5 by the first and second imaging means 3A and 3B. The distance between the edge 5c parallel to the conveying direction or the edge of the laser processed groove and the reference position of the first and second imaging means 3A, 3B (the position corresponding to the first cylindrical lens 18a) And the CAD data stored in the memory 23 described later are compared to calculate the distance deviation amount.

  Further, the memory 23 stores an initial set value and laser processing CAD data input by operating an operation unit (not shown), and stores a calculation result in the calculation unit 22.

  The stage drive controller 24 compares the output of the speed sensor of the stage 1 with the speed information input in advance and stored in the memory 23 by operating the operation means, and reciprocates the stage 1 at a constant speed. When the laser processing in the direction is completed, the stage 1 is moved in the Y-axis direction by a distance corresponding to the step movement amount stored in the memory 23.

  Further, the laser light source drive controller 25 controls the light emission of the laser light source 14. The laser light source drive controller 25 causes the laser light source 14 to emit light after a predetermined time elapses after detecting the edges 5 a and 5 b orthogonal to the conveyance direction of the substrate 5. The light is emitted intermittently at the time interval. And the control part 26 controls so that each said component may operate | move appropriately.

Next, the operation of the first embodiment of the laser processing apparatus configured as described above and the manufacture of the thin-film solar cell 6 will be described with reference to the flowchart shown in FIG. 7 and FIG.
First, in step S1, CAD data is stored in the memory 23, and an operation means (not shown) is operated to move the movement speed and distance of the stage 1 in the X-axis direction, the step movement amount in the Y-axis direction, and the like. The number of feeds is input and initialized, and stored in the memory 23. In this case, the moving speed of the stage 1 is set so that a part of each laser processing pattern overlaps a predetermined amount with respect to the light emission period of 50 Hz of the laser light source 14. As CAD data, data stored in a CD-ROM or the like may be read into the memory 23.

  In step S2, positioning adjustment between the laser head 2 and the stage 1 is performed. That is, a mark provided on the laser head 2 and the stage 1 is detected by an alignment camera provided separately, and the lens array 20 of the laser head 2 is rotated and moved by a rotation mechanism (not shown) so that both marks have a predetermined positional relationship. The long axis of each cylindrical lens 18 is set so as to be parallel to the transport direction (X-axis direction) of the substrate 5. This positioning may be performed manually or automatically.

  In step S3, the substrate 5 on which the transparent electrode layer 7 is formed on the upper surface of the transparent substrate 5 as shown in FIG. 8A is positioned and placed at a predetermined position on the stage 1.

  In step S4, when the start switch is turned on, the substrate 5 is transported at a constant speed from the right to the left in FIG. 1 in the X-axis direction, and the laser processing of the forward path is started.

  In this case, first, the position of the edge portion 5a (one end) on the top side in the transport direction of the substrate 5 orthogonal to the transport direction is detected from the captured image of the first image capturing means 3A and stored in the memory 23. Specifically, the input switching unit 27 of the image processing unit 21 is switched to the first imaging unit 3A side to acquire an image captured by the first imaging unit 3A, and the acquired one-dimensional image is stored in the buffer memory 28. save. Then, the one-dimensional image stored in the buffer memory 28 is sequentially read out, and the first position detection unit 29 performs pixel interpolation in the transport direction (X-axis direction) of the substrate 5 to detect a sudden change position of the luminance change, The sudden change position is extracted as the edge 5a on the leading side in the transport direction of the substrate 5, and the position of the stage 1 at the time of extraction of the edge 5a is detected by the X position sensor and stored in the memory 23.

  Next, the position of one edge 5c of the two edges of the substrate 5 parallel to the transport direction is detected from the captured image of the first imaging means 3A and stored in the memory 23. Specifically, the one-dimensional image by the first imaging unit 3A stored in the buffer memory 28 is read out, and the second position detection unit 30 performs pixel interpolation in the light receiving element arrangement direction (Y-axis direction) to obtain luminance. The sudden change position is detected, the sudden change position is extracted as the position of the one edge portion 5 c parallel to the transport direction of the substrate 5, and the position information is stored in the memory 23.

  Subsequently, the position information of one edge 5c parallel to the conveyance direction of the substrate 5 and the reference position information of the first imaging means 3A are read from the memory 23 and subtracted by the calculation unit 22, and the distance L between the two is calculated. Is calculated. Further, among the CAD data read from the distance L and the memory 23, the dimension L2 from one edge 5c of the substrate 5 to the edge of the first first separation groove 10a shown in FIG. 3B. And the stage drive controller 24 moves the stage 1 in the Y-axis direction so that L = L2, and each cylindrical lens 18 is positioned at the position where the first separation groove 10 is formed. This operation is always performed while the substrate 5 is being transported, and the first separation groove 10 is formed in parallel with one edge portion 5 c parallel to the transport direction of the substrate 5.

  Further, the position information of the leading edge 5a in the transport direction of the substrate 5 is read from the memory 23, and the position information and the position information input from the X position sensor are compared by the arithmetic unit 22, and as shown in FIG. The distance D in which the substrate 5 has moved after the leading edge 5a in the transport direction 5 is detected is calculated. When the moving distance D of the substrate 5 becomes D = D1 + L1 + L6 / 2, the laser light source drive controller 25 is driven to cause the laser light source 14 to emit light and to emit laser light having a wavelength of 1064 nm. Thereafter, the laser light source 14 is controlled by the laser light source drive controller 25 and repeatedly emits light at a cycle of 50 Hz.

  The diameter of the laser light emitted from the laser light source 14 is enlarged by the beam expander 15, the luminance distribution is made uniform by the uniformizing means 16, and parallel light parallel to the optical axis is made by the condenser lens 17, and the lens array 20. Is incident on. The laser light incident on the lens array 20 is shaped into a plurality of laser beams having a cross-sectional thin line shape by a plurality of cylindrical lenses 18 and irradiated onto the substrate 5, and is parallel to the transport electrode axis on the transparent electrode layer 7 on the substrate 5. A plurality of fine laser processing patterns arranged at predetermined intervals are formed.

  The calculation unit 22 calculates the distance the substrate 5 has moved after detecting the leading edge 5a in the transfer direction of the substrate 5 based on the position information input from the X position sensor at all times during the transfer of the substrate 5. Then, the distance is compared with the CAD data read from the memory 23 to determine whether or not the substrate 5 has moved by a predetermined distance. Here, when it is detected that the substrate 5 has moved by a predetermined distance, the laser light source drive controller 25 stops the light emission of the laser light source 14. As a result, the plurality of laser processing patterns are connected in a straight line in a state where a part of the laser processing patterns overlaps, and the first separation groove 10 having a predetermined length is formed.

  In step S5, when the stage 1 moves by a preset distance, the stage drive controller 24 controls the stage 1 to stop moving in the X-axis direction. Subsequently, the stage 1 is step-moved from the back side to the near side in FIG. 1 in the Y-axis direction by the step movement amount read from the memory 23. At that time, the number of step feeds in the Y-axis direction is counted and stored in the memory 23.

  In step S6, the stage 1 is moved at a constant speed from the left to the right in FIG. At this time, the input switching unit 27 of the image processing unit 21 is switched to the second imaging unit 3B side, and based on the image data by the second imaging unit 3B, the leading edge 5b in the transport direction of the substrate 5 is the same as described above. (The other end) is detected, and the light emission timing of the laser light source 14 is controlled based on the edge 5b. Further, the edge of the first separation groove 10 immediately adjacent to the plurality of first separation grooves 10 laser-processed in the immediately forward path is detected based on the image data from the second imaging means 3B, and the edge and Laser processing is performed while the stage 1 is displaced in the Y-axis direction so that the distance from the reference position of the second imaging means 3B (corresponding to the position of the first cylindrical lens 18a of the lens array 20) is L5. As a result, a plurality of first separation grooves 10 are formed in parallel to the first separation grooves 10 formed in the outward path in the return path.

  In step S7, the controller 26 determines whether or not the number of step feeds of the stage 1 in the Y-axis direction has reached a predetermined number. If the determination is “NO”, the process proceeds to step S8, and the stage 1 is stepped by a predetermined distance from the back side to the near side in FIG. 1 in the Y-axis direction. At the same time, the number of feeds is counted and stored in the memory 23. Then, returning to step S4, steps S4 to S8 are repeatedly executed until “YES” is determined in step S7. In this case, the positioning reference for laser processing in step S4 is not the one edge portion 5c parallel to the conveyance direction of the substrate 5, but the first separation groove 10 immediately adjacent among the plurality of first separation grooves 10 laser-processed in the immediately preceding return path. This is the edge of one separation groove 10.

  If “YES” is determined in step S8, the process proceeds to step S9, where the stage 1 returns to the machining start position and stops. As a result, as shown in FIG. 8B, a plurality of first separation grooves 10 are formed in the transparent electrode layer 7.

  Next, as shown in FIG. 8C, the photoelectric conversion layer 8 is formed so as to cover the transparent electrode layer 7, and the photoelectric conversion is performed as shown in FIG. A contact line 11 is formed on the layer 8. In this case, in step S4, based on the image data from the first image pickup means 3A, the one edge portion 5c parallel to the transport direction of the substrate 5 and the reference position of the first image pickup means 3A are always during laser processing. The stage 1 is displaced in the Y-axis direction so that the distance between them becomes L3. Further, the positioning reference for laser processing in step S6 and subsequent steps is the edge of the contact line 11 immediately adjacent among the plurality of contact lines 11 laser-processed in the immediately preceding return path or forward path. Further, in the last laser processing, the cylindrical lens 18b (see FIG. 4) positioned at the opposite end to the first cylindrical lens 18a of the lens array 20 is shielded from light. As the laser light of the laser light source 14 used here, a laser light having a wavelength of 532 nm is selected so that only the photoelectric conversion layer 8 is laser processed.

  When a plurality of contact lines 11 are formed on the photoelectric conversion layer 8 in this way, the back electrode layer 9 is formed so as to cover the photoelectric conversion layer 8 as shown in FIG. As a result, the second separation groove 12 is formed on the back electrode layer 9 as shown in FIG. In this case, in step S4, based on the image data from the first image pickup means 3A, the one edge portion 5c parallel to the transport direction of the substrate 5 and the reference position of the first image pickup means 3A are always during laser processing. The stage 1 is displaced in the Y-axis direction so that the distance between them becomes L4. Further, the positioning reference for laser processing in step S6 and subsequent steps is the edge of the second separation groove 12 immediately adjacent among the plurality of second separation grooves 12 laser-processed in the immediately preceding return path or forward path. Furthermore, also in this case, in the last laser processing, the cylindrical lens 18b located at the opposite end to the first cylindrical lens 18a of the lens array 20 is shielded from light. The laser light of the laser light source 14 used here is a laser light having a wavelength of 532 nm so that only the photoelectric conversion layer 8 and the back electrode layer 9 are laser processed.

  Finally, as shown in FIG. 8 (g), an electrode 13 is formed on the back electrode layer 9 in the vicinity of the edge parallel to the transport direction of the substrate 5, so that the thin-film solar shown in FIGS. A battery 6 is formed.

  In the first embodiment, the groove to be laser-processed next is compared with one edge 5c parallel to the axis of the substrate 5 in the transport direction and the edge of the groove formed by laser processing first. Although the case where the stage 1 is displaced in the Y-axis direction during positioning has been described, the present invention is not limited to this, and the lens array 20 or the laser light source 14 may be displaced in the Y-axis direction.

  In the first embodiment, the case where the laser beam irradiation timing control and the laser processing positioning control are performed based on the edge of the substrate 5 has been described. However, the present invention is not limited to this, and the substrate The edge of the thin film layer formed on 5 may be used as a reference.

  Furthermore, in the first embodiment, after a predetermined time has elapsed, the first imaging unit 3A detects the edge 5a of the substrate 5 and the second imaging unit 3B detects the edge 5b of the substrate 5. Although the case where the laser light source 14 is caused to emit light has been described, the present invention is not limited to this, and the first or second imaging means 3A, 3B detects the edge on the leading side in the transport direction of the previously laser processed groove. The laser light source 14 may emit light after a predetermined time has elapsed with reference to the detection time.

  A shutter that shields a laser beam that passes through the cylindrical lens 18 is provided so as to be able to move forward and backward in the vicinity of a predetermined cylindrical lens 18 of a lens array 20 configured by arranging a plurality of cylindrical lenses 18 at regular intervals. The pitches of the plurality of laser beams generated in (1) may be changeable. Thereby, it is possible to cope with the formation of a plurality of types of solar cells 6 having different formation pitches such as the first separation grooves 10 with one lens array 20.

  FIG. 10 is a plan view showing a main part of a second embodiment of the laser processing apparatus according to the present invention. The difference from the first embodiment is that the substrate 5 is conveyed in one direction (X-axis direction) by, for example, a belt conveyor (conveying means), and two cylindrical lenses 18 are arranged at a predetermined interval parallel to the conveyance direction of the substrate 5. The first lens pair 31 and the second lens pair 32 in which two cylindrical lenses 18 are arranged at a predetermined interval orthogonal to the transport direction of the substrate 5 are provided apart from each other by a predetermined distance in the transport direction of the substrate 5. The image pickup means is separated from the center of the first lens pair 31 by D2 and separated from the center of the second lens pair 32 by D3 on the front side in the transport direction of the laser beam irradiation position by each of the lens pairs 31 and 32. 3, each lens pair is formed by a rotating means (not shown) so as to be rotatable about a center by a predetermined angle as indicated by an arrow in the figure, and a lens moving means (not shown) More distance between the two cylindrical lenses 18 of the lens pair 31 and 32 is variable. Further, each lens pair 31 and 32 is movable in the Y-axis direction by a lens pair moving means (not shown).

  Next, the operation of the second embodiment configured as described above will be described. The substrate 5 used here is a rectangular substrate of the solar cell 6 made of crystalline silicon. In this case, since the n-type doping layer is formed so as to cover the outer surface of the rectangular substrate 5, a groove is formed along each edge at a position a predetermined distance from each edge of the surface of the substrate 5. Thus, it is necessary to electrically separate the front surface electrode and the back surface electrode. In the second embodiment, two laser beam pairs are generated by the first and second lens pairs 31 and 32 to irradiate the substrate 5, and the separation groove is parallel to each edge of the rectangular substrate 5. Is to try to form. This will be described below with reference to FIG.

  First, the one-dimensional image picked up by the image pickup means 3 is subjected to pixel interpolation in the transport direction (X-axis direction) of the substrate 5 and the arrangement direction of the light receiving elements (Y-axis direction), and the substrate 5 shown in FIG. The position coordinates of the edges P1, P2, P3, and P4 are detected and stored in the memory 23. In this case, the X coordinate of each edge is determined by the movement distance of the substrate 5 with respect to the edge P1.

  Next, the position coordinates of each edge stored in the memory 23 are read to calculate the rotation angle θ of the substrate 5, and the center position coordinates of the substrate 5 and the distance between the opposite sides of the substrate 5 are calculated in the memory 23. save.

  Subsequently, the center position coordinates of the substrate 5 stored in the memory 23 are read out, and the shift amount in the Y-axis direction of the substrate 5 from the center axis line in the transport direction (center line passing through the center of the imaging means 3) is calculated. Then, the first and second lens pairs 31 and 32 are moved in the Y-axis direction by the same amount as the shift amount by the lens pair moving means. Further, the rotating means is driven based on the rotation angle θ of the substrate 5 stored in the memory 23 to rotate the lens pairs 31 and 32 by the angle θ. Further, the distance between the opposite sides of the substrate 5 stored in the memory 23 is read out and compared with CAD data stored in advance in the memory 23, and the irradiation position of the laser beam is a predetermined distance inside each edge of the substrate 5. The distance between the cylindrical lenses 18 facing each other is adjusted by driving the lens moving means so as to be positioned.

  Then, after the center of the substrate 5 is detected by the imaging means 3, the substrate 5 is transported by the distance D2, and the center of the substrate 5 coincides with the center of the first lens pair 31 as shown in FIG. The laser light source 14 emits light for a predetermined time as controlled by the laser drive controller. As a result, the laser light emitted from the laser light source 14 is irradiated to the substrate 5 by being converted into a laser beam having a thin cross-section by the two cylindrical lenses 18 of the first lens pair 31, and is shown in FIG. Thus, two separation grooves 33a are formed in parallel to the two edges of the substrate 5, respectively.

  Further, after the center of the substrate 5 is detected by the imaging means 3, the substrate 5 is transported by the distance D3, and the center of the substrate 5 coincides with the center of the second lens pair 32 as shown in FIG. The laser light source 14 emits light for a predetermined time as controlled by the laser drive controller. As a result, the laser light emitted from the laser light source 14 is irradiated with the two cylindrical lenses 18 of the second lens pair 32 into a laser beam having a thin cross-sectional shape and irradiated onto the substrate 5, as shown in FIG. As described above, two separation grooves 33b are formed in parallel to the two edges of the substrate 5, respectively. In this way, the separation grooves 33a and 33b are formed at positions inside the respective edges of the substrate 5 by a predetermined distance, and the front surface electrode and the back surface electrode of the crystalline silicon solar cell 6 can be completely separated. it can.

  According to this 2nd Embodiment, the some board | substrate 5 can be continuously conveyed with a belt conveyor, and can be laser-processed, and the efficiency of a laser processing process can be improved. Moreover, since it is not necessary to position and mount the board | substrate 5 on a belt conveyor, work efficiency improves.

  In the second embodiment, the case where the first and second lens pairs 31 and 32 are formed to be movable in the Y-axis direction has been described. However, the present invention is not limited to this, and each lens pair is formed. The cylindrical lenses 18 of the first lens pair 31 may be individually moved in the Y-axis direction and the cylindrical lenses 18 of the second lens pair 32 may be individually moved in the X-axis direction while 31 and 32 are fixed. .

  In the first and second embodiments, the substrate 5 is transported while being held on the upper surface of the stage 1, and laser is applied to the substrate 5 by the laser head 2 disposed above the stage 1 and facing the upper surface. Although the case of irradiating a beam has been described, the present invention is not limited to this, and the laser head 2 is disposed below the stage 1 and the substrate 5 held and transported by the stage 1 is irradiated with the laser beam. There may be.

  In the above description, the case where the substrate 5 is the solar cell 6 has been described. However, the present invention is not limited to this, and the substrate 5 is not limited as long as the grooves are formed in parallel at a predetermined interval. There may be.

1 is a schematic configuration diagram showing a first embodiment of a laser processing apparatus according to the present invention. It is a top view which shows the example of 1 structure of the thin film type solar cell formed by the said 1st Embodiment. It is sectional drawing of the said thin film type solar cell, (a) is the OO sectional view taken on the line of FIG. 2, (b) is the QQ sectional view taken on the line of FIG. It is a figure which shows the lens array used in the said 1st Embodiment, (a) is a top view, (b) is a right view. It is a block diagram which shows schematic structure of the control means in the said 1st Embodiment. It is a block diagram which shows the structural example of the image process part of the said control means. It is a flowchart which shows the laser processing operation by the said 1st Embodiment. It is process drawing shown about manufacture of the said thin film type solar cell. It is explanatory drawing which shows the laser irradiation timing by the said 1st Embodiment. It is a top view which shows the principal part of 2nd Embodiment of the laser processing apparatus by this invention. It is explanatory drawing which shows the laser processing operation | movement by the said 2nd Embodiment.

Explanation of symbols

1. Stage (conveying means)
DESCRIPTION OF SYMBOLS 2 ... Laser head 3 ... Imaging means 3A ... 1st imaging means 3B ... 2nd imaging means 4 ... Control means 5 ... Substrate 6 ... Solar cell 14 ... Laser light source 18 ... Cylindrical lens 20 ... Lens array 31 ... 1st Lens pair 32 ... Second lens pair

Claims (7)

A laser processing apparatus that performs laser processing by irradiating a laser beam from a laser light source onto the substrate while holding the substrate by a transport means and transporting the substrate in a certain direction.
A laser head provided with a plurality of cylindrical lenses for generating a plurality of laser beams having a thin cross-sectional shape from the laser light emitted from the laser light source and irradiating the substrate;
Imaging means arranged to image a position on the near side in the transport direction of a laser beam irradiation position by the plurality of cylindrical lenses;
Control means for controlling the irradiation timing of the laser beam and the irradiation position of the laser beam emitted from the laser light source on the basis of the captured image of the imaging means;
A laser processing apparatus comprising:   The laser head has the plurality of cylindrical lenses arranged at a predetermined pitch so that the major axis thereof is substantially parallel to the axis in the substrate transport direction within a plane parallel to the substrate holding surface of the transport means. The laser processing apparatus according to claim 1, further comprising a lens array configured.   3. The laser processing apparatus according to claim 2, wherein the lens array is formed so as to be movable in a direction orthogonal to the transport direction of the substrate relative to the transport means. The substrate has a rectangular shape,
The laser head includes a first lens pair in which two cylindrical lenses are arranged at a predetermined interval parallel to the substrate transport direction, and a first lens pair in which two cylindrical lenses are disposed at a predetermined interval orthogonal to the substrate transport direction. 2. The laser processing apparatus according to claim 1, wherein the two lens pairs are separated from each other by a predetermined distance in the substrate transport direction.   The first and second lens pairs are respectively formed to be rotatable so that the irradiation position of the laser beam by each cylindrical lens is parallel to the edge of the rectangular substrate to be conveyed. The laser processing apparatus according to claim 4.   6. The laser processing apparatus according to claim 4, wherein the first lens pair and the second lens pair are formed such that a distance between the two cylindrical lenses is variable.   The laser processing apparatus according to claim 1, wherein the substrate is a substrate of a solar cell.

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