JP2010052031A - Laser processing apparatus, method for producing solar cell panel, solar cell panel and laser processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily remove powder produced by scribing treatment of cutting a thin film. <P>SOLUTION: The laser processing apparatus comprises: a laser light source 11 irradiating a thin film formed at a substrate 2 with laser light and oscillating the laser light for cutting the thin film; and an UV lamp 15 irradiating the powder of the thin film scattered when the thin film is cut with ultraviolet light, so as to act the ultraviolet light on the powder. By irradiating the powder scattered from the thin film toward the upper direction with ultraviolet light when the thin film is cut by the laser light, the powder is modified, so as to be a stock having a material different from that of the thin film. The modification-finished powder dropped on the thin film is sucked away by an air duct 17, and can be easily removed from the thin film. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a laser processing apparatus that performs laser processing on a thin film formed on a substrate, a solar cell panel manufacturing apparatus, a solar cell panel, and a laser processing method.

  An amorphous silicon solar cell panel, which is a type of solar cell panel, has a transparent electrode layer, a photoelectric conversion layer, and a back electrode layer laminated on a transparent substrate as a thin film. A metal oxide such as SnO (tin oxide) is used as the thin film of the transparent electrode layer and the back electrode layer, and amorphous (non-crystalline) silicon is used as the thin film of the photoelectric conversion layer. Each thin film is formed by being sequentially deposited on a substrate by a vapor deposition method such as a CVD (vapor deposition method). A general solar battery panel employs a structure in which a photoelectric conversion layer is divided into a plurality of cells, and the cells are connected in series. By changing the number of stages of each cell, it is possible to arbitrarily set the voltage as the solar battery panel.

In order to divide the solar cell panel into a plurality of cells, a scribing process (or a laser etching process) is performed in which a thin film of each layer is cut to form a groove portion in order to divide the thin film into a plurality of regions. For example, Patent Documents 1 and 2 disclose techniques for performing the scribing process. In Patent Document 1, the substrate is mounted on a transparent stage and the thin film is cut by irradiating laser light from the stage side. In Patent Document 2, the thin film is cut by irradiating laser light while blowing gas. .
JP-A-6-326337 JP 2001-320071 A

  As in Patent Documents 1 and 2, the thin film is cut by irradiating the laser beam, and the thin film is partially removed at the time of cutting, and the removed thin film becomes a fine powder such as dust and moves upward. The scattered powder falls and reattaches to the thin film. Since the dropped powder reduces the smoothness of the surface of the thin film, the powder dropped on the thin film must be removed from the viewpoint of quality improvement. However, since the powder dropped on the substrate is originally the same material as the thin film, it is difficult for the dropped powder and the thin film to adhere to each other or adhere to each other and be removed. For this reason, in order to reliably remove the powder from the thin film, it is necessary to perform cleaning using a dedicated cleaning liquid or the like, which requires a cleaning process and a cleaning mechanism, and reduces productivity and complexity of the mechanism. Invites

  As described above, a plurality of thin films are stacked on the substrate, and a scribing process is performed on each thin film in order to divide the thin film into a plurality of regions. For this reason, when vapor-depositing the thin film laminated | stacked next with respect to the thin film by which the scribe process was carried out, you must make it vapor-deposit, after removing a powder reliably. Therefore, the scribing process and the cleaning process must be alternately repeated, which greatly reduces productivity. Further, in Patent Document 2, gas is blown and removed with respect to the powder generated by the scribing process. However, since the powder has a very small particle size, it can be completely obtained by blowing the gas. The powder cannot be removed. For this reason, in order to remove the remaining powder, it is still necessary to perform cleaning, resulting in a decrease in productivity and a complicated mechanism.

  Then, an object of this invention is to remove easily the powder produced by the scribe process which cuts a thin film.

  In order to solve the above-described problems, a laser processing apparatus according to claim 1 of the present invention includes a laser beam irradiation means for irradiating a thin film formed on a substrate with laser light to cut the thin film, and the thin film. And a dry cleaning means for irradiating the thin film powder scattered when the film is cut with ultraviolet light and causing the ultraviolet light to act on the powder.

  According to this laser processing apparatus, the powder scattered by the scribing process is modified by the action of ultraviolet light, and the powder becomes a material different from the thin film. Even if the powder on which the ultraviolet light has acted falls on the thin film, the affinity between the powder and the thin film is reduced or lost, and the powder can be easily separated. Thereby, the powder is easily removed. Since the scattered powder must be irradiated with ultraviolet light before falling onto the thin film, dry cleaning should be performed by irradiating with ultraviolet light in parallel with the cutting of the thin film by laser irradiation. Is desirable. By performing laser light irradiation and dry cleaning in parallel, ultraviolet light can act before the powder falls, making it easy to separate the powder and cutting and drying the thin film. By simultaneously performing the cleaning, the processing time can be shortened.

  The laser processing apparatus according to claim 2 of the present invention is the laser processing apparatus according to claim 1, wherein the dry cleaning means includes an ultraviolet light irradiation means for irradiating the powder with ultraviolet light, and a powder on which the ultraviolet light acts. And a suction removing means for sucking and removing the body.

  According to this laser processing apparatus, the powder to which the ultraviolet light has acted has reduced or lost affinity with the thin film, and can be easily removed from the thin film by simply performing suction removal by the suction removal means.

  According to a third aspect of the present invention, there is provided the laser processing apparatus according to the first aspect, further comprising a moving means for relatively moving the laser light source and the substrate.

  According to this laser processing apparatus, since the substrate and the laser light source can be moved relative to each other, the thin film can be cut into a desired pattern. Since the thin film is basically cut in one direction, the direction of relative movement may be one direction. However, if the thin film can be moved in two directions orthogonal to each other, a desired pattern can be cut. become.

  According to a fourth aspect of the present invention, there is provided a solar cell panel manufacturing apparatus comprising the laser processing apparatus according to any one of the first to third aspects. Moreover, the solar cell panel of Claim 5 of this invention was manufactured with the manufacturing apparatus of the solar cell panel of Claim 4.

  The laser processing apparatus can be applied to a solar cell panel manufacturing apparatus. In a solar battery panel in which a thin film is laminated on a substrate, the laser processing apparatus described above can be applied to remove powder generated by the scribing process because a scribing process for dividing the thin film into a plurality of cells is performed.

  A laser processing method according to claim 6 of the present invention is a thin film cutting step in which the thin film formed on the substrate is cut by irradiating laser light to divide the thin film into a plurality of regions, and the thin film cutting step. Irradiating the thin film powder scattered in step 1 with ultraviolet light and applying the ultraviolet light to the powder; and suction removal for sucking and removing the powder after the action of the ultraviolet light And a process.

  In the present invention, ultraviolet light is applied to the thin film powder generated when the thin film scribe process is performed. Therefore, even if the powder after the ultraviolet light action falls on the thin film, it adheres to or adheres to the thin film. The powder can be easily removed. This eliminates the need for a cleaning step and a cleaning mechanism, so that productivity can be improved and the mechanism can be simplified.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this embodiment, a case where a solar cell panel is applied will be described. However, as long as the thin film is partially removed by irradiating the thin film with laser light, the solar cell panel can be applied to other than the solar cell panel. You may apply.

  FIG. 1 is a schematic configuration diagram of a laser processing apparatus 1 of the present invention. The laser processing apparatus 1 has a schematic configuration mainly including a workpiece 2, a mounting stage 3, a stage moving unit 4, and a processing unit 5. The target object 2 is an object to be processed by the laser processing apparatus 1 and has a substrate 6 as a basic configuration. The substrate 6 is a transparent glass substrate, and various thin films for exhibiting the function of the solar cell panel are deposited on the substrate 6. Accordingly, the workpiece 2 is the substrate 6 when the thin film is not deposited, and includes the substrate 6 and the deposited thin film when the thin film is deposited.

  The mounting stage 3 is a stage for mounting and holding the substrate 6 in the workpiece 2. The stage moving unit 4 can move the mounting stage 3 in one direction, and is a moving means for moving the mounting stage 3 and the processing unit 5 relative to each other. In the example of FIG. 1, the processing unit 5 is fixed and the mounting stage 3 is moved, but the mounting stage 3 may be fixed and the processing unit 5 may be moved. Moreover, in order to move both relatively, you may move both the process unit 5 and the mounting stage 3. FIG. Although the mounting stage 3 is movable in one direction, it may be movable in two directions orthogonal to each other on a plane.

  The processing unit 5 includes a laser light source 11, a beam expander 12, a PBS (polarization beam splitter) 13, an objective lens 14, a UV (Ultra Violet) lamp 15, an air nozzle 16, and an air duct 17, and is schematically configured. Are united together. As described above, when the moving unit is provided in the processing unit 5, each part of the processing unit 5 is integrally moved relative to the mounting stage 3 by the moving unit.

  The laser light source 11 is a light source that oscillates laser light having a predetermined wavelength, and a thin film scribing process (or laser etching process) is performed by the laser light. Since the thin film reacts in different wavelength ranges depending on its material, the laser light source 11 oscillates laser light having a wavelength corresponding to the thin film to be scribed. The beam expander 12 is an optical component provided to widen the beam diameter of the laser light emitted from the laser light source 11. The PBS 13 is an optical component that is disposed at an angle of 45 degrees with respect to the optical path of the laser light, transmits one direction of polarized light in two directions orthogonal to each other, and reflects the other polarized light. The objective lens 14 is a lens for condensing the laser beam reflected by the PBS 13 onto a thin film to be scribed. The beam expander 12, the PBS 13, and the objective lens 14 are optional components, and other optical components may be used as long as the scribing process can be performed by irradiating the thin film with laser light. .

  The UV lamp 15 is a lamp for irradiating ultraviolet light. The UV lamp 15 is disposed so as to irradiate ultraviolet light toward an upper position of a portion where the thin film formed on the object 2 is subjected to a scribing process, and is directed obliquely downward from the upper position of the air nozzle 16. Irradiating with ultraviolet light. Although the UV lamp 15 is applied in FIG. 1, any light source that irradiates ultraviolet light can be applied. For example, a laser light source that irradiates laser light in the ultraviolet light region (wavelength near 355 nm) may be applied.

  The air nozzle 16 is a discharge unit that discharges air, and the air duct 17 is a suction removal unit that removes powder after reforming, which will be described later, by sucking air. The air nozzle 16 is provided with an air discharge port 16A that discharges air toward a site of the object 2 to be processed obliquely below, and the air duct 17 has an air suction port 17A that sucks air at an object to be processed diagonally below. It is provided toward the part of the body 2 to be scribed. Accordingly, an air flow is generated from the air nozzle 16 toward the air duct 17 via a portion of the workpiece 2 that is scribed. Although the air nozzle 16 and the air duct 17 are used here, any means may be used as long as it forms an air flow. Further, the air nozzle 16 need not be provided as long as the air flow can be created only by the air duct 17, but it is desirable to create a strong air flow to some extent using both the air nozzle 16 and the air duct 17.

  Laser processing using the above configuration will be described. The solar cell panel has a configuration in which a transparent electrode layer, a photoelectric conversion layer, and a back electrode layer are sequentially laminated as a thin film, and a thin film (here, SnO film 7) as a transparent electrode layer is first deposited. The object 2 to be processed at this time is a substrate 6 on which no thin film is formed, and an SnO film 7 as a transparent electrode layer is deposited on the entire surface of the substrate 6 by a CVD method or the like. And the to-be-processed object 2 with which the SnO film | membrane 7 was vapor-deposited is located in the lower part of the process unit 5, and a scribe process is started. Laser light having a wavelength of 1064 nm is oscillated from the laser light source 11. This is because SnO reacts to light in the vicinity of a wavelength of 1064 nm and does not react to light in other wavelength regions. The laser light oscillated from the laser light source 11 is applied to the SnO film 7 of the workpiece 2 via the beam expander 12, the PBS 13, and the objective lens 14.

  The irradiated laser light reacts with the SnO film 7 and the portion of the SnO film 7 irradiated with the laser light is removed as shown in FIG. The SnO film 7 is cut in one direction by irradiating the laser beam so that the surface of the substrate 6 is exposed by the laser beam irradiation, and the stage moving unit 4 moves the mounting stage 3 in one direction. 7A is formed. By forming the groove 7A at a plurality of locations of the SnO film 7, the SnO film 7 is divided into a plurality of regions, and there is no portion connected to each region.

  Although the SnO film 7 is partially removed by irradiation with the laser light, the removed SnO film 7 becomes powder D having a very small particle size and scatters upward. Here, as also shown in FIG. 2, an air flow is generated by the air nozzle 16 and the air duct 17, and this air flow is directed from the air nozzle 16 to the vicinity of the groove 7A and from the vicinity of the groove 7A to the air duct 17. There is a flow towards it. Accordingly, the powder D that is scribed and scattered upward is collected toward the air duct 17 by this air flow. However, a very large number of dust-like powders D are swollen upward during the scribing process, so that all cannot be recovered in the air duct 17, and the unrecovered powder D is the SnO film 7. Fall into.

  In the present invention, the laser light irradiation from the laser light source 11 and the ultraviolet light irradiation from the UV lamp 15 are performed in parallel. As a result, the powder D that has been scribed and scattered is irradiated with ultraviolet light before falling onto the SnO film 7. When the ultraviolet light is irradiated, the powder D (SnO) is activated and modified (or sintered), and the bond between tin and oxygen is broken to produce tin and oxygen as metals. As a result, the modified powder D becomes metallic tin, which is a different material from SnO. Therefore, even if the modified powder D falls on the SnO film 7, SnO and Sn are different from each other, so the affinity is reduced or lost, and the powder D and the SnO film 7 are not connected. Adhesiveness hardly acts and can be easily removed.

  As described above, the scribing process for irradiating laser light to cut the SnO film 7 and the ultraviolet light irradiation process for applying ultraviolet light to the powder D generated by the scribing process are performed in parallel. That is, while the powder D scattered by the scribing process is in a floating state, it is irradiated with ultraviolet light to act. For this reason, the UV lamp 15 irradiates ultraviolet light obliquely from above so as not to affect the optical path of laser light incident from a direction orthogonal to the SnO film 7. Thereby, before the powder D falls, the ultraviolet light can be applied to make it different from the SnO film 7, and the floating powder D falls on the SnO film 7 without being collected by the air flow. Can be easily removed. In this case, the optical path of the laser light and the optical path of the ultraviolet light are overlapped with each other. However, since the wavelength ranges of the laser light and the ultraviolet light are different from each other, they do not affect each other. .

  Since the powder D scattered by the scribing process is scattered upward, the powder D that has not been recovered by the air flow does not diffuse so widely and falls around the groove 7A. Since the groove portion 7A is a path of air flow by the air nozzle 16 and the air duct 17, the dropped powder D tends to be captured by the air flow. Since the powder D almost loses the affinity with the SnO film 7, it is easily removed from the SnO film 7 by the air flow and collected in the air duct 17. Accordingly, the powder D can be easily and completely removed without requiring a separate cleaning step and a cleaning mechanism, so that the next thin film can be formed.

  Here, the irradiation energy of the UV light of the UV lamp 15 is set low. Since the size of the powder D is extremely small, even if the energy is low, the ultraviolet light can be sufficiently applied to the powder D, and if the irradiation energy of the ultraviolet light is set high, the SnO film 7 is affected. It is because there is a possibility of giving.

  Next, an α-Si film 8 as a photoelectric conversion layer is deposited on the entire surface of the SnO film 7 of the object 2 to be processed. A plurality of grooves 7A are formed in the SnO film 7, and an α-Si film 8 is deposited on the entire surface of the SnO film 7 including each groove 7A. Then, as shown in FIG. 3, the α-Si film 8 is also cut by a scribing process in the same manner as the SnO film 7 to form groove portions 8A at a plurality of locations. At this time, the laser light source 11 oscillates a laser beam having a wavelength of 532 nm. This is because the wavelength range in which the α-Si film 8 reacts is near 532 nm. Even if the α-Si film 8 is irradiated with ultraviolet light, the α-Si film 8 itself is not changed into a material having a different property, but the surface of the α-Si film 8 is nano-ordered by irradiating the ultraviolet light. The oxide film is formed. Thereby, an effect equivalent to that of the modification is obtained, and the affinity between the powder D (the α-Si film on which the oxide film is formed) and the α-Si film 8 is almost lost. Therefore, it can be easily removed by an air flow. The groove 8A is formed not at the same position as the groove 7A in the thickness direction of the workpiece 2 but at a different position. Since the powder D is scattered in the scribing process for forming the groove 8A, the powder D is modified by irradiating with ultraviolet light, and the air flow generated by the air nozzle 16 and the air duct 17 is reliably modified. The removed powder D is removed.

  Next, a SnO film 9 as a back electrode layer is deposited on the entire surface of the α-Si film 8 of the object to be processed 2 (including the substrate 6, the SnO film 7 and the α-Si film 8). The α-Si film 8 has a plurality of grooves 8A formed therein, and a SnO film 9 is deposited on the entire surface of the α-Si film 8 including each groove 8A. Then, as shown in FIG. 4, cutting is performed by a scribing process. At this time, not only the SnO film 9 but also the α-Si film 8 is removed to form the groove 9A. That is, the scribing process is performed on the two layers from the surface.

  At this time, laser light with a wavelength of 1064 nm may be irradiated to remove the SnO film 9, and then laser light with a wavelength of 532 nm may be irradiated to remove the α-Si film 8. It is only necessary to irradiate the α-Si film 8 with laser light. Since the laser beam having a wavelength of 532 nm does not react with the SnO film 9, the laser beam passes through the SnO film 9 and is irradiated to the α-Si film 8, and the irradiated portion is removed. Along with this, the SnO film 9 is also removed together with the α-Si film 8, so that a groove 9A as shown in FIG. 4 is formed at a plurality of locations. Since the powder D is scattered even when the scribing process for forming each groove 9A is performed, the modification is performed by irradiating ultraviolet light, and the modified powder D is removed by the air flow.

  The groove 9A is formed at a position different from the groove 7A and the groove 8A in the thickness direction of the object 2 to be processed. Accordingly, the groove 7A, the groove 8A, and the groove 9A are formed at different positions. The SnO film 7 as the transparent electrode layer is divided into a plurality of regions by the groove portion 7A, the α-Si film 8 as the photoelectric conversion layer is divided into a plurality of regions by the groove portion 8A, and the SnO film 9 as the back electrode layer is the groove portion. Divided into a plurality of areas by 9A. Thereby, the solar cell panel is divided into a plurality of cells. In addition, since the SnO film 7 as the transparent electrode layer and the SnO film 9 as the back electrode layer are electrically connected by the groove 8A, the cells are connected in series.

  Therefore, every time a thin film of each layer is deposited, a scribing process is performed, and a thin film deposition and a scribing process are alternately performed. For this reason, the scribing process is repeated a plurality of times. In each scribing process, the powder D falling on the thin film can be easily removed by modifying the powder D with ultraviolet light. Therefore, the cleaning process and the cleaning mechanism are not required. Therefore, productivity can be improved and the mechanism can be simplified.

  In the present embodiment, the case where the SnO film is applied to the transparent electrode layer and the back electrode layer has been described as an example. However, the present invention is not limited to this, and ZnO (zinc oxide), ITO (indium tin oxide), or the like is applied. A metal material other than a metal oxide may be applied. Different materials may be applied to the transparent electrode layer and the back electrode layer. As the photoelectric conversion layer, the one to which α-Si is applied has been described. However, single crystal silicon, polycrystalline silicon, microcrystalline silicon, or the like may be used, or a workpiece system such as GaAs or CIS (chalcopyrite) may be used. A material may be used. Although each thin film laminated | stacked on the board | substrate 6 demonstrated vapor deposition by CVD method, arbitrary vapor deposition methods, such as sputtering method and an ion plating method, may be applied.

It is a schematic block diagram of a laser processing apparatus. It is the figure explaining the state which is performing the scribing process with respect to the transparent electrode layer. It is a figure explaining the state which is performing the scribing process with respect to the photoelectric converting layer. It is the figure explaining the state which is performing the scribe process with respect to a back electrode layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser processing apparatus 2 To-be-processed object 3 Mounting stage 4 Stage moving part 5 Processing unit 6 Substrate 7 SnO film 8 α-Si film 9 SnO film 11 Laser light source 15 UV lamp 16 Air nozzle 17 Air duct D Powder

Claims (6)

Laser light irradiation means for irradiating a thin film formed on a substrate with laser light and cutting the thin film;
Dry cleaning means for irradiating ultraviolet light to the powder of the thin film scattered when the thin film is cut, and causing the ultraviolet light to act on the powder;
A laser processing apparatus comprising: The dry cleaning means includes
Ultraviolet light irradiation means for irradiating the powder with ultraviolet light;
Suction removal means for sucking and removing the powder on which the ultraviolet light has acted;
The laser processing apparatus according to claim 1, further comprising:   The laser processing apparatus according to claim 1, further comprising a moving unit that relatively moves the laser light source and the substrate.   An apparatus for manufacturing a solar cell panel, comprising the laser processing apparatus according to any one of claims 1 to 3.   A solar cell panel manufactured by the solar cell panel manufacturing apparatus according to claim 4. A thin film cutting step of performing a cut by irradiating a laser beam to a thin film formed on a substrate and dividing the thin film into a plurality of regions;
Irradiating the thin film powder scattered in the thin film cutting process with ultraviolet light, and applying the ultraviolet light to the powder;
A suction removal step of sucking and removing the powder after the action of the ultraviolet light;
The laser processing method characterized by having.

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