JP2012256738A - Manufacturing method of photovoltaic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a photovoltaic device capable of dividing a semiconductor substrate into a plurality of photovoltaic devices in a simple step.SOLUTION: A manufacturing method of a photovoltaic device comprises; a printing step of printing an electrode covering a second principal surface of a semiconductor substrate having a first principal surface which serves as a light-receiving surface and the second principal surface on the opposite side of the first principal surface; a groove formation step of forming a groove on the first principal surface so that the groove overlaps the electrode when seen through in a direction perpendicular to the first principal surface; and a division step of dividing the semiconductor substrate into a plurality of photovoltaic devices by bending the semiconductor substrate so as to rotate with the groove as nearly a central axis.

Description

  The present invention relates to a method for manufacturing a photovoltaic device.

  In the process of manufacturing a semiconductor device, a manufacturing method is generally used in which a plurality of devices are formed on a semiconductor substrate and then the semiconductor substrate is divided into individual devices.

  In Patent Document 1, a mask member having a plurality of openings formed on the back surface of a semiconductor substrate is attached, a metal layer is deposited by a sputtering apparatus, the mask member is peeled off, and a street between a plurality of formed electrodes. The modified layer is formed by irradiating a laser beam along the surface of the semiconductor substrate, and the adhesive tape is attached to the back surface of the semiconductor substrate to expand the adhesive tape. As a result, according to Patent Document 1, a tensile force acts radially on the semiconductor substrate, and the semiconductor substrate is broken along the streets whose strength has been reduced by the formation of the altered layer, and is divided into individual devices. It is said that.

  However, when a material having higher ductility than a semiconductor substrate such as solder is applied to the semiconductor substrate by screen printing, it is difficult to divide the material having high ductility.

  On the other hand, in Patent Document 2, a solder layer is formed by printing on an electrode layer on the backside of a semiconductor wafer, an adhesive tape is attached to the backside of the semiconductor wafer, and the solder layer is cut while cutting the semiconductor wafer along the street. Describes forming a shallow groove and expanding the adhesive tape. Thus, according to Patent Document 1, a tensile force is radially applied to the semiconductor wafer and the solder layer, the solder layer is broken along the shallow processed groove with the shallow processed groove as a division base point, and the semiconductor wafer is separated into individual semiconductor chips. It is said that the occurrence of cutting defects can be prevented.

JP 2010-016116 A JP 2010-182901 A

  On the other hand, a silicon crystal photovoltaic device (solar cell) has electrodes on almost the entire back surface opposite to the light receiving surface. A typical example of this electrode is an aluminum paste obtained by diffusing aluminum powder in a solvent, applied by screen printing, and fired. When a semiconductor substrate coated with an electrode (aluminum) on the back surface is divided into a plurality of photovoltaic devices, the main body portion (silicon) of the semiconductor substrate can be easily divided, but it is difficult to divide the electrode (aluminum).

  When dividing such a semiconductor substrate into a plurality of photovoltaic devices, when the dividing method described in Patent Document 1 is used, if the position accuracy of electrode printing is low, the street provided for facilitating the division is erroneous. As a result, the electrodes may be applied, and the process yield may be reduced.

  In addition, when the dividing method described in Patent Document 2 is used, it is difficult to remove the separated semiconductor device from the elastic adhesive tape, and the semiconductor device may be cracked or chipped, thereby reducing the yield. There is. In order to prevent cracks and chipping of semiconductor devices, it is necessary to remove individual semiconductor devices from the adhesive tape over time, and the number of devices cut out from one substrate like a photovoltaic device is increased to ten. If it is less, the manufacturing tact per device tends to be too long.

  This invention is made | formed in view of the above, Comprising: It aims at obtaining the manufacturing method of the photovoltaic device which can divide | segment a semiconductor substrate into a several photovoltaic device by a simple process.

  In order to solve the above-described problems and achieve the object, a method of manufacturing a photovoltaic device according to one aspect of the present invention is the first main surface that should be a light-receiving surface and the opposite of the first main surface. A printing step of printing an electrode covering the second main surface of the semiconductor substrate having a second main surface on the side, and overlapping the electrode when seen through from a direction perpendicular to the first main surface A groove forming step of forming a groove in the first main surface, and a division of dividing the semiconductor substrate into a plurality of photovoltaic devices by bending the semiconductor substrate so as to rotate about the groove And a process.

  According to the present invention, since the semiconductor substrate is divided into a plurality of photovoltaic devices by bending the semiconductor substrate, there is no need to use a stretchable adhesive tape, and the step of removing the divided photovoltaic device from the adhesive tape Is also unnecessary. Thereby, the semiconductor substrate can be divided into a plurality of photovoltaic devices by a simple process.

FIG. 1 is a diagram illustrating a method of manufacturing the photovoltaic device according to the first embodiment. FIG. 2 is a diagram illustrating the method of manufacturing the photovoltaic device according to the first embodiment. FIG. 3 is a diagram illustrating the method of manufacturing the photovoltaic device according to the first embodiment. FIG. 4 is a diagram illustrating a method of manufacturing the photovoltaic device according to the second embodiment.

  Embodiments of a method for manufacturing a photovoltaic device according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
The manufacturing method of the photovoltaic apparatus concerning Embodiment 1 is demonstrated using FIGS. 1-3.

  In the process shown in FIG. 1, a semiconductor substrate 103 is prepared. The semiconductor substrate 103 is made of, for example, crystalline silicon (for example, single crystal silicon or polycrystalline silicon). The semiconductor substrate 103 has a first main surface 103a and a second main surface 103b. The first main surface 103a is a surface to be a light receiving surface of each of the photovoltaic devices PPD1 to PPD4 (see FIG. 3B). The second main surface 103b is a main surface opposite to the first main surface 103a.

  A predetermined surface treatment is performed on the first main surface 103a of the semiconductor substrate 103 to form a texture (uneven pattern). Then, the p− layer 104 and the p + layer 102 are respectively formed on the first main surface 103a and the second main surface 103b of the semiconductor substrate 103 by a thermal diffusion method or the like.

  Next, the electrode 101 is printed on, for example, substantially the entire surface of the second main surface 103b of the semiconductor substrate 103, and then dried. The electrode 101 is printed by applying an aluminum paste to the second main surface 103b of the semiconductor substrate 103 through a printing mask, for example, by a screen printing method. Subsequently, the semiconductor substrate 103 is turned upside down to print, for example, the light receiving surface electrode 105 on the first main surface 103a of the semiconductor substrate 103, and then dried and baked. The light receiving surface electrode 105 is printed by applying a silver paste to the first main surface 103a of the semiconductor substrate 103 of the semiconductor substrate 103 through a printing mask, for example, by screen printing. Thereby, the semiconductor substrate 100 including the semiconductor substrate 103, the electrode 101, and the light receiving surface electrode 105 is obtained. Hereinafter, the semiconductor substrate 103 is referred to as a main body portion 103.

  In the step shown in FIG. 2, scribe grooves 106-1 and 106-2 are formed in the first main surface 103a of the semiconductor substrate 100. At this time, the scribe grooves 106-1 and 106-2 are formed so as to overlap the electrode 101 when seen through from a direction perpendicular to the first main surface 103a of the semiconductor substrate 100. That is, when viewed from a direction perpendicular to the first main surface 103a, for example, the four portions delimited by the scribe grooves 106-1 and 106-2 in the semiconductor substrate 100 are four photovoltaic devices PPD1 to PPD4. This is the part that should be.

  Scribe grooves 106-1 and 106-2 are provided by adsorbing the second main surface 103b of the semiconductor substrate 100 with a laser processing stage (not shown) and passing the fixed laser irradiation position at a constant speed. For example, the laser beam is provided by scanning the first main surface 103a along the broken line with a polygon mirror or a galvanometer mirror. As the laser light, a YAG laser fundamental wave (wavelength 1064 nm), a second harmonic (wavelength 532 nm), or the like is suitable. The depth of the scribe grooves 106-1 and 106-2 is preferably approximately one third of the thickness of the semiconductor substrate 103.

  3A, the second main surface 103b of the semiconductor substrate 100 is sucked by the suction mechanism 108 attached to the bending arm 107, and the semiconductor substrate 100 is moved up to the vicinity of the jig 109. At this time, the position of the ridge line portion 109a of the push-up jig 109 is acquired by, for example, the imaging device 120 and stored in a predetermined storage device (not shown). Then, while acquiring the position of the semiconductor substrate 100 by the imaging device 120, for example, alignment is performed so that the scribe groove 106-2 is positioned above the ridge line portion 109a of the push-up jig 109 stored in the storage device.

  In the step shown in FIG. 3B, the semiconductor substrate 100 is pushed up against the jig 109 by releasing the suction by the suction mechanism 108 and lowering the bending arm 107. At this time, the end portion on the first main surface 103 a side of the semiconductor substrate 100 is supported by the columnar portion 110 of the bending arm 107. The push-up jig 109 is provided with two inclined surfaces 109b and 109c. For this reason, when the semiconductor substrate 100 is pressed against the pushing jig 109, the ridge line portion 109a formed by the two inclined surfaces 109b and 109c pushes up so as to push the scribe groove 106-2. That is, the semiconductor substrate 100 is bent so as to rotate about the scribe groove 106-2 as a central axis.

  The process shown in FIGS. 3A and 3B is also performed on the scribe groove 106-1. Thereby, the semiconductor substrate 100 is divided into a plurality of photovoltaic devices PDD1 to PDD4.

  Note that a curvature is provided in the ridge line portion 109a, and the semiconductor substrate 100 is not easily damaged by the push-up jig 109 even if the positions of the scribe groove 106-2 and the push-up jig 109 are changed.

  Here, when the semiconductor substrate 100 is bent until the rotation angle θ reaches 5 degrees, the main body portion 103 (crystalline silicon) of the semiconductor substrate 100 is divided. However, the electrode 101 (aluminum) has not been divided yet. The electrode 101 (aluminum) can be divided after the bending rotation angle θ becomes 15 degrees or more. The rotation angle θ varies depending on the compounding ratio of the material of the aluminum electrode, the thickness, the firing temperature, and the like, but is preferably 15 to 35 degrees within the range we have experimented.

  If the rotation angle θ is smaller than 15 degrees, the electrode 101 (aluminum) tends not to be divided. When the rotation angle θ is larger than 35 degrees, the photovoltaic device after splitting is cracked or chipped, and the yield tends to deteriorate.

  As described above, in the first embodiment, the scribe grooves 106-1 and 106-2 having a predetermined depth are formed in the semiconductor substrate 100, and the scribe grooves 106-1 and 106-2 are rotated about the central axis. In this way, the semiconductor substrate 100 is bent to divide the semiconductor substrate 100 into a plurality of photovoltaic devices PDD1 to PDD4. For this reason, it is not necessary to use the adhesive tape with elasticity, and the process which removes the divided photovoltaic devices PDD1-PDD4 from an adhesive tape becomes unnecessary. Therefore, the semiconductor substrate 100 can be divided into a plurality of photovoltaic devices PDD1 to PDD4 by a simple process.

  Moreover, since the process which removes the divided photovoltaic devices PDD1-PDD4 from an adhesive tape is unnecessary, the tact which took the removal process can be shortened, and the cost of an adhesive tape can be reduced. In addition, there is an advantage that the yield can be improved by eliminating cracks / chips that have occurred when the photovoltaic devices PDD1 to PDD4 are removed from the adhesive tape. Furthermore, since there is no need to provide a street, the yield does not decrease due to the positional accuracy of electrode printing.

  In the first embodiment, the scribe grooves 106-1 and 106-2 are formed by laser light. Thereby, the scribe grooves 106-1 and 106-2 can be easily formed.

  Furthermore, in the first embodiment, the rotation angle when the semiconductor substrate 100 is bent is 15 degrees or more. Thereby, the electrode 101 made of a material having higher ductility than the semiconductor substrate 100 can be easily divided.

  Note that the scribe grooves 106-1 and 106-2 may be formed by a cutting blade. Even in this case, the scribe grooves 106-1 and 106-2 can be easily formed.

Embodiment 2. FIG.
A method for manufacturing the photovoltaic device according to the second embodiment will be described. Below, it demonstrates focusing on a different part from Embodiment 1. FIG.

  In the process shown in FIG. 4A, the second main surface 103b of the semiconductor substrate 100 is sucked and fixed by a laser processing stage (not shown) (the sucked and fixed state in the process shown in FIG. 2). The first main surface 103a side of the semiconductor substrate 100 is adsorbed by the bending plate 111 while maintaining. Thereafter, the suction by the laser processing stage is released. The bending plate 111 is composed of a pair of a first plate 111 a and a second plate 111 b, and both or one of them is configured to rotate about the rotation shaft 112. The apparatus is assembled so that the rotation shaft 112 substantially coincides with the scribe groove 106-2 formed on the semiconductor substrate 100. That is, the position of the rotating shaft 112 of the bending plate 111 is acquired by, for example, the imaging device 120 and stored in a predetermined storage device (not shown). Then, while acquiring the position of the semiconductor substrate 100 by the imaging device 120, for example, alignment is performed so that the scribe groove 106-2 is positioned above the rotation shaft 112 of the bending plate 111 stored in the storage device. This alignment may be performed, for example, in the process shown in FIG.

  In the step shown in FIG. 4B, by rotating the bending plate 111, a crack is developed in the main body portion 103 of the semiconductor substrate 100 starting from the scribe groove 106-2, and the rotation angle θ is 5 degrees. At that time, the main body portion 103 (silicon) is broken. Thereafter, the electrode 101 (aluminum) can also be broken by bending until the rotation angle θ is 15 degrees or more. The bending rotation angle θ at which the electrode 101 (aluminum) breaks varies depending on the type of electrode, the coating thickness, and the firing conditions, but 15 to 30 degrees is suitable within the range we have experimented.

  Here, when the semiconductor substrate 100 with the electrode 101 (aluminum) is divided, the electrode 101 (aluminum) is peeled off from the semiconductor substrate 100 and scattered as dust, or is not peeled off and remains on the semiconductor substrate 100 as burrs. May occur. The amount of dust and burrs generated depends on the positional relationship between the scribe grooves 106-1 and 106-2 and the rotation center of bending.

  On the other hand, in the second embodiment, the semiconductor substrate 100 is received from the laser processing stage to the bending plate 111 without changing the position of the semiconductor substrate 100 provided with the scribe grooves 106-1 and 106-2 by laser processing. Therefore, the alignment position accuracy between the scribe grooves 106-1 and 106-2 and the rotating shaft 112 can be kept high, and the generation of dust and burrs can be suppressed.

  Further, the bending rotation angle necessary for the division varies depending on the thickness of the electrode and the firing conditions, but the apparatus according to the present embodiment has an advantage that the bending rotation angle can be easily increased.

  As described above, the method for manufacturing a photovoltaic device according to the present invention is useful for manufacturing a silicon crystal-based photovoltaic device.

DESCRIPTION OF SYMBOLS 100 Semiconductor substrate 101 Electrode 102 p + layer 103 Semiconductor substrate, main-body part 103a 1st main surface 103b 2nd main surface 104 p-layer 105 Light-receiving surface electrode 106-1 and 106-2 Scribe groove 107 Bending arm 108 Adsorption mechanism 109 Push-up jig 110 Cylindrical portion 111 Bending plate 112 Rotating shaft 120 Imaging device PPD1 to PPD4 Photovoltaic device

Claims (3)

A printing step of printing an electrode covering the second main surface of the semiconductor substrate having a first main surface to be a light receiving surface and a second main surface opposite to the first main surface;
A groove forming step of forming a groove in the first main surface so as to overlap the electrode when seen through from a direction perpendicular to the first main surface;
A dividing step of dividing the semiconductor substrate into a plurality of photovoltaic devices by bending the semiconductor substrate so as to rotate about the groove as a central axis;
A method for manufacturing a photovoltaic device, comprising: The method for manufacturing a photovoltaic device according to claim 1, wherein in the groove forming step, a groove is formed in the first main surface by a cutting blade or laser light. The method for manufacturing a photovoltaic device according to claim 1, wherein in the dividing step, a rotation angle when the semiconductor substrate is bent is 15 degrees or more.

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