JP2008294365A - Method of manufacturing solar cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a solar cell in which productivity is enhanced. <P>SOLUTION: In the column surface 11 of a columnar semiconductor crystal ingot 100, a first groove 31 is formed continuously in the height direction on the column surface 11 and the first groove 31 indicates information for specifying the columnar semiconductor crystal ingot 100. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a solar cell formed using a semiconductor crystal ingot.

  Solar cells are expected as new energy sources because they directly convert clean and inexhaustible sunlight into electricity.

  Since the output per solar cell is about several watts, a solar cell module in which a plurality of solar cells are arranged is used when a solar cell is used as a power source for a house or a building. The solar cell has a light receiving surface that receives sunlight and a back surface provided on the opposite side of the light receiving surface.

Here, in order to manage individual solar cells included in the solar cell module, identification indicating information such as date of manufacture, country of manufacture, manufacturer, etc. on the light receiving surface, back surface or side surface of each solar cell It has been proposed to form a label (see Patent Document 1).
JP 2004-200514 A

  On the other hand, the characteristic defect of the solar cell is often caused by the characteristic defect of the semiconductor crystal ingot. In such a case, it is necessary to investigate the cause of the characteristic defect retroactively when the semiconductor crystal ingot is manufactured. Therefore, information (manufacturing lot, date of manufacture, etc.) specifying the semiconductor crystal ingot is important for quality control of the solar cell.

  However, when the identification mark is formed after the solar cell is formed as described above, it is necessary to separately manage information for specifying the semiconductor crystal ingot until after the solar cell is formed. Moreover, in order to add the information which specifies a semiconductor crystal ingot to a solar cell, it is necessary to form an identification mark for each individual solar cell.

  Due to the above complicated management and an increase in the number of manufacturing steps, productivity may be reduced.

  Further, since the semiconductor crystal ingot is sliced into a thin semiconductor crystal substrate, it is troublesome to individually form the identification mark in accordance with the position to be cut out as the semiconductor crystal substrate, which may further reduce the productivity.

  The present invention has been made in view of the above problems, and an object thereof is to provide a method for manufacturing a solar cell with improved productivity.

  A feature of the present invention is that a semiconductor crystal substrate is formed by slicing the semiconductor crystal ingot, and a step A of forming a first marker continuous on the column surface of the columnar semiconductor crystal ingot in the height direction of the column surface And a step C of forming a solar cell using the semiconductor crystal substrate, wherein the first label indicates information identifying the semiconductor crystal ingot.

  According to the feature of the present invention, since the first mark is continuously formed in the height direction on the column surface of the semiconductor crystal ingot, the first groove mark is efficiently applied to all the semiconductor crystal substrates cut out from the semiconductor crystal ingot. Can be formed. Moreover, the semiconductor crystal ingot used for the solar cell which a characteristic defect generate | occur | produced can be simply identified using the 1st label | marker of the solar cell using a semiconductor crystal substrate. Thereby, the follow-up survey can be performed efficiently until the semiconductor crystal ingot is manufactured (manufacturer, manufacturing date, manufacturing conditions, etc.). Moreover, since a solar cell can be formed using the semiconductor crystal substrate in which the 1st label | marker which shows the information which specifies a semiconductor crystal ingot was previously formed, until a solar cell preparation is completed, a semiconductor crystal ingot is specified. There is no need to manage information separately. Therefore, the productivity of the solar cell can be improved as compared with the case where the identification mark is formed for each solar cell.

  In the feature of the present invention, it is preferable that the first marker is constituted by a plurality of grooves, and information specifying the semiconductor crystal ingot is indicated by a combination of the plurality of grooves.

  In the feature of the present invention, in the step A, a second label that is continuous in the height direction of the column surface is further formed on the column surface of the semiconductor crystal ingot, and the second label is a height in the semiconductor crystal ingot. It is preferable to indicate information for specifying the position in the vertical direction.

  In the characteristics of the present invention, the column surface of the semiconductor crystal ingot is configured by a plurality of planes, and the first label and the second label are formed on different planes among the plurality of planes. Preferably it is.

  ADVANTAGE OF THE INVENTION According to this invention, the solar cell module which improved the electric power generation amount per unit area which provides the manufacturing method of the solar cell which improved productivity can be provided.

  Next, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones. Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

(Semiconductor crystal ingot processing)
First, a semiconductor crystal ingot 100 is prepared. FIG. 1 shows a semiconductor crystal ingot 100 used in this embodiment. The semiconductor crystal ingot 100 is formed in a quadrangular column shape and has four column surfaces 11 to 14. The four column surfaces 11 to 14 are uniformly formed from the first plane (upper surface) 21 to the second plane (bottom surface) 22.

  As the semiconductor crystal ingot 100, a silicon-based semiconductor crystal ingot such as a single crystal silicon ingot formed by a CZ method, an FZ method, an EFG method or the like, or a polycrystalline silicon ingot formed by a cast method or the like can be used. The semiconductor crystal ingot 100 is not limited to a silicon-based semiconductor crystal ingot but may be a compound-based semiconductor crystal ingot such as GaAs. In this embodiment, as an example, the semiconductor crystal ingot 100 formed in a quadrangular prism shape is used, but may be formed in another polygonal column shape, a cylindrical shape, or the like. The semiconductor crystal ingot 100 may use a columnar semiconductor crystal block obtained by cutting a semiconductor crystal ingot formed by a predetermined method into a plurality of pieces by a band saw device or the like.

  Next, as shown in FIG. 2, the semiconductor crystal ingot 100 is specified on the column surface 11, and the first groove 31 continuous in the height direction of the column surface 11 is formed. Specifically, the first groove 31 having a predetermined depth is formed from the first plane 21 to the second plane 22 by a laser beam engraving method, an etching corrosion method, or the like. The 1st groove | channel 31 which concerns on this embodiment is an identification mark which shows the information which specifies the semiconductor crystal ingot 100 by the combination of the groove | channel in the direction orthogonal to a height direction comprised by several groove | channels. Here, the information for specifying the semiconductor crystal ingot 100 is information useful for specifying the semiconductor crystal ingot 100 used for production from a solar cell produced using the semiconductor crystal ingot 100. Therefore, as information for specifying the semiconductor crystal ingot 100, for example, information such as a manufacturer, a manufacturing date, a manufacturing lot number, and manufacturing conditions can be arbitrarily selected.

  Next, the height direction position of the semiconductor crystal ingot 100 is specified on the column surface 12, and the second groove 32 continuous in the height direction of the column surface 12 is formed. Specifically, the second groove 32 continuous from the first plane 21 to the second plane 22 is formed with a predetermined depth by a laser beam engraving method, an etching corrosion method, or the like. The 2nd groove | channel 32 which concerns on this embodiment is comprised by one groove | channel. The second groove 32 is an identification mark indicating information for specifying a position in the height direction of the semiconductor crystal ingot 100. In the present embodiment, the second groove 32 is formed so as to have a predetermined inclination with respect to the height direction. Therefore, the position from the first plane 21 and the second plane 22 can be determined from the position where the second groove 32 is formed in the direction orthogonal to the height direction.

  Thus, the 1st groove | channel 31 is a label | marker for identifying the specific semiconductor crystal ingot between semiconductor crystal ingots, and the 2nd groove | channel 32 is for identifying the specific position in a specific semiconductor crystal ingot. It is a sign. In addition, what is necessary is just to form the 1st groove | channel 31 and the 2nd groove | channel 32 by the depth of the grade which does not reduce the output of a solar cell, when a solar cell is formed using the semiconductor crystal ingot 100. FIG.

  Next, the semiconductor crystal ingot 100 is sliced by a wire saw device or the like. Thereby, a semiconductor crystal substrate (wafer) is formed. FIG. 3 schematically shows a plurality of semiconductor crystal substrates 10 cut out from the semiconductor crystal ingot 100. FIG. 4 shows an enlarged semiconductor crystal substrate 10. As shown in FIG. 3, in all the semiconductor crystal substrates 10, the first groove 31 is formed on one side surface, and the second groove 32 is formed on the other side surface. As shown in FIG. 4, the first groove 31 and the second groove 32 are continuously formed from one main surface of the semiconductor crystal substrate 10 to another main surface provided on the opposite side of the one main surface. It is formed with a depth of. Accordingly, one main surface and the other main surface have recesses corresponding to the first groove 31 and the second groove 32. In other words, the sides forming one main surface and the other main surface have an uneven shape corresponding to the first groove 31 and the second groove 32. In addition, the 1st groove | channel 31 is formed like the barcode label | marker in one side surface.

  In addition to the first groove 31 and the second groove 32 according to the present embodiment, the semiconductor crystal ingot 100 may be formed with notches and orientation flats for specifying the plane orientation of the semiconductor crystal substrate 10.

(Formation of solar cells)
Next, a solar cell is formed using the semiconductor crystal substrate 10. As such a solar cell, a general solar cell having a semiconductor junction such as a semiconductor pn junction or a semiconductor pin junction formed using the semiconductor crystal substrate 10 as a basic structure can be formed. Below, an example of the manufacturing method of a solar cell is demonstrated using FIG.5 and FIG.6. The conductivity type of the semiconductor crystal substrate 10 may be either n-type or p-type, but the description will be made assuming that the conductivity type of the semiconductor crystal substrate 10 is n-type.

  First, the surface of the n-type semiconductor crystal substrate 10 is washed to remove impurities.

  Next, an i-type amorphous semiconductor layer 41 and a p-type amorphous semiconductor layer 42 are sequentially stacked on one main surface of the n-type semiconductor crystal substrate 10 by using a vapor phase growth method such as an RF plasma CVD method. To do. Similarly, an i-type amorphous semiconductor layer 43 and an n-type amorphous semiconductor layer 44 are sequentially stacked on the other main surface of the n-type semiconductor crystal substrate 10.

  Next, an ITO film 45 is formed on the p-type amorphous semiconductor layer 42 by using a magnetron sputtering method. Similarly, an ITO film 46 is formed on the n-type amorphous semiconductor layer 44. Thus, the photoelectric conversion unit 47 is formed.

  Next, an epoxy thermosetting silver paste 48 is formed in a comb shape on the ITO film 45 using a printing method such as a screen printing method or an offset printing method. Similarly, an epoxy thermosetting silver paste (not shown) is formed on the entire surface of the ITO film 46. Thereby, the current collection electrode which collects the photogenerated carrier produced | generated in the photoelectric conversion part 47 is formed.

  Thus, the solar cell 1 shown in FIG. 6 is formed. Here, as shown in FIG. 4, one main surface and the other main surface of the semiconductor crystal substrate 10 have recesses corresponding to the first groove 31 and the second groove 32. Therefore, one main surface of the solar cell 1 formed using such a semiconductor crystal substrate 10 and the other main surface provided on the opposite side of the one main surface are the first groove 31 and the second groove 32. Has a recess corresponding to.

(Function and effect)
According to the method for manufacturing a solar cell according to the present embodiment, the first groove 31 that is continuous in the height direction of the column surface 11 is formed on the column surface 11 of the columnar semiconductor crystal ingot 100. The first groove 31 shows information for specifying the semiconductor crystal ingot 100.

  Thus, since the 1st groove | channel 31 is continuously formed in the height direction in the column surface 11 of the semiconductor crystal ingot 100, the 1st groove | channel 31 is formed in all the semiconductor crystal substrates 10 cut out from the semiconductor crystal ingot 100. It can be formed efficiently. In addition, by using the first groove 31 formed in the solar cell 1 using the semiconductor crystal substrate 10, it is possible to easily identify the semiconductor crystal ingot used in the solar cell in which the characteristic defect has occurred. Thereby, the follow-up survey can be performed efficiently until the semiconductor crystal ingot is manufactured (manufacturer, manufacturing date, manufacturing conditions, etc.).

  Further, since the solar cell can be formed using the semiconductor crystal substrate 10 in which the first groove 31 indicating the information specifying the semiconductor crystal ingot 100 is previously formed, the semiconductor crystal ingot is manufactured until the solar cell is manufactured. There is no need to separately manage information identifying 100. Therefore, the productivity of the solar cell can be improved as compared with the case where the identification mark is formed for each solar cell.

  According to the method for manufacturing a solar cell according to the present embodiment, the first groove 31 is constituted by a plurality of grooves, and information for specifying a semiconductor crystal ingot is indicated by a combination of the plurality of grooves.

  As described above, by using the first groove 31 like a bar code label, information specifying the semiconductor crystal ingot 100 can be mechanically read. As a result, the identification mark can be efficiently identified without being misidentified.

  According to the method for manufacturing a solar cell according to the present embodiment, the second groove 32 continuous in the height direction of the column surface 12 is formed on the column surface 12 of the columnar semiconductor crystal ingot 100. The second groove 32 indicates information for specifying the position in the height direction of the semiconductor crystal ingot 100.

  Here, generally, the variation in specific resistance value inside the semiconductor crystal ingot tends to increase in the height direction of the semiconductor crystal ingot. Since the specific resistance value greatly affects the characteristics of the solar cell 1, information for identifying the position in the height direction of the semiconductor crystal ingot plays an important role in analyzing the cause of the characteristic failure of the solar cell.

  Therefore, by using the information specifying the position in the height direction of the semiconductor crystal ingot 100 indicated by the second groove 32, the manufacturing conditions and the like of the semiconductor crystal ingot can be improved more precisely.

  Furthermore, since the 1st groove | channel 31 and the 2nd groove | channel 32 are formed with the depth of the grade which does not affect the output of the solar cell 1, the label | marker which shows desired information, without reducing the output of a solar cell. Can be formed.

(Other embodiments)
Although the present invention has been described according to the above-described embodiments, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  For example, in the above-described embodiment, the first groove 31 and the second groove 32 are formed as signs indicating desired information. However, the first groove 31 and the second groove 32 can be used as long as there is no alteration due to heating and there is no fear of releasing impurities. Therefore, as long as these conditions are satisfied, ink or the like may be applied instead of the first groove 31 and the second groove 32.

  In the above embodiment, the first groove 31 and the second groove 32 are formed before the slicing process of the semiconductor crystal ingot 100. However, a plurality of semiconductor crystal substrates 10 formed by slicing the semiconductor crystal ingot 100 are stacked. Grooves can be formed in the combined state.

  Moreover, in the said embodiment, although the 1st groove | channel 31 and the 2nd groove | channel 32 were formed in the respectively different column surface (column surface 11 and column surface 12), you may form in the same column surface.

  In the above embodiment, the semiconductor crystal ingot 100 is used, but a columnar semiconductor crystal block obtained by cutting the semiconductor crystal ingot 100 into a plurality of pieces by a band saw device or the like may be used. Also in this case, the second groove 32 only needs to indicate information for specifying the height direction in the semiconductor crystal ingot 100.

  Moreover, in the said embodiment, although the 1st groove | channel 31 and the 2nd groove | channel 32 were formed in the semiconductor crystal ingot 100, if it is not necessary to specify the height direction of a semiconductor crystal ingot, the 2nd groove | channel 32 is not formed. May be.

  Moreover, in the said embodiment, although the 1st groove | channel 31 was comprised by the some groove | channel, if a semiconductor crystal ingot can be pinpointed by the position where one groove | channel is formed, the 1st groove | channel 31 will be comprised by one groove | channel. It may be configured.

  Moreover, in the said embodiment, although the 2nd groove | channel 32 was comprised by one groove | channel, you may comprise by a some groove | channel.

It is an external view of the semiconductor crystal ingot 100 used for embodiment. It is a figure which shows the 1st groove | channel 31 and the 2nd groove | channel 32 which were formed in the semiconductor crystal ingot 100 used for embodiment. It is a figure showing semiconductor crystal substrate 10 cut out from semiconductor crystal ingot 100 used for an embodiment. 1 is an enlarged view of a semiconductor crystal substrate 10. FIG. 2 is a diagram showing a photoelectric conversion unit 47 formed using a semiconductor crystal substrate 10. FIG. 1 is a diagram showing a solar cell 1 formed using a semiconductor crystal substrate 10. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Solar cell 10 ... Semiconductor crystal substrate
DESCRIPTION OF SYMBOLS 100 ... Semiconductor crystal ingot 11-14 ... Column surface 21 ... 1st plane 22 ... 2nd plane 31 ... 1st groove | channel 32 ... 2nd groove | channel 41 ... i-type amorphous semiconductor layer 42 ... p-type amorphous semiconductor layer 43 ... i-type amorphous semiconductor layer 44 ... n-type amorphous semiconductor layer 45 ... ITO film 46 ... ITO film 47 ... photoelectric conversion part 48 ... silver paste

Claims (4)

Forming a first marker that is continuous in the height direction of the column surface on the column surface of the columnar semiconductor crystal ingot; and
Forming a semiconductor crystal substrate by slicing the semiconductor crystal ingot; and
And forming a solar cell using the semiconductor crystal substrate,
The method for producing a solar cell, wherein the first label indicates information for identifying the semiconductor crystal ingot. The first marker is composed of a plurality of grooves,
The method for manufacturing a solar cell according to claim 1, wherein the information specifying the semiconductor crystal ingot is indicated by a combination of the plurality of grooves. In the step A, a second label that is continuous in the height direction of the column surface is further formed on the column surface of the semiconductor crystal ingot;
The method for manufacturing a solar cell according to claim 1, wherein the second label indicates information for specifying a position in a height direction of the semiconductor crystal ingot. The column surface of the semiconductor crystal ingot is composed of a plurality of planes,
The said 1st label | marker and the said 2nd label | marker are each formed in a mutually different plane among these several planes, The manufacturing method of the solar cell of Claim 3 characterized by the above-mentioned.

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