JP5617659B2 - Manufacturing method of solar cell - Google Patents

Description

The present invention is particularly thin thickness of the solar cell substrate processing relates to the production how effective solar cell when processing.

Current solar power has a problem that the power generation cost is still higher than that of conventional commercial power. Therefore, a significant reduction in manufacturing cost is required. In particular, in the mainstream crystalline silicon solar cells, the cost reduction due to the thinning of the substrate is progressing. Currently, it is 150 to 250 μm, but it is said that it is necessary to realize 50 to 100 μm in the future.
However, when the substrate is thinned in this way, the mechanical strength of the substrate itself is reduced, making it difficult to handle in the production process.

Therefore, conventionally, in order to supplement the strength of the thin substrate, a method of forming a joined body joined to a plate-like holding base for holding the substrate and transporting or processing the substrate has been used.
Regarding the formation of the joined body, there has been proposed a method (Japanese Patent Laid-Open No. 2006-156679: Patent Document 1) in which a holding base and a substrate are detachably adhered with an adhesive. However, the pressure-sensitive adhesive removing process is complicated, and a pressure-sensitive adhesive residue often occurs on the substrate surface, which may impair device quality. Further, the substrate may be damaged during the peeling process. In addition, since the pressure-sensitive adhesive uses an organic substance, there is a restriction that it cannot be used in a process where the processing temperature exceeds several hundred degrees.

  On the other hand, a method has been proposed in which the substrate and the holding table are transported together without bonding the substrate and the holding table (Japanese Patent Laid-Open No. 2008-10448: Patent Document 2). In this method, as shown in FIG. 1, the substrate 101 and the holding plate 102 are arranged on the suction jig 103 that performs vacuum suction, and the substrate 101 and the holding plate 102 are vacuum-sucked simultaneously. Vacuum suction is performed from a suction port 103c provided in the suction jig 103, and the holding plate 102 is sucked to the suction jig by the suction port 103b. The substrate 101 is sucked and fixed from a suction port 103 c provided in the suction jig 103 via a through hole 102 a provided in the holding plate 102. After a predetermined operation, the substrate 101 is released from the suction jig together with the holding plate 102 and is transported while being placed on the holding plate.

  However, in this method, since the substrate being transported is opened on the holding plate, the substrate falls off the holding plate. For this reason, for example, a process of providing protrusions on the outer periphery of the substrate holding portion of the holding plate is performed to prevent the substrate from falling off. However, such a shape of the holding plate is not only complicated and expensive, but also has a limitation that projections and steps for preventing the substrate from falling off become obstacles, and a process such as screen printing cannot be applied.

  On the other hand, in many batch processing apparatuses that process a large number of sheets simultaneously in one batch, the substrates are generally transported and processed in a cassette or boat in which a large number of substrates are vertically packed, so that the substrates are independent. This method, which is not fixed, cannot be applied to the mass production process of solar cells.

JP 2006-156679 A JP 2008-10448 A

The present invention has been made in view of the above problems, without the use of adhesives to hold the thin solar cell substrate with a simple structure, to provide a manufacturing how the Ru solar cell can transport and processing Objective.

In order to achieve the above object, the present invention provides the following solar cell manufacturing method.
Claim 1:
A step of holding the solar cell substrate in an atmosphere of a pressure P1 lower than atmospheric pressure on a holding plate having a concave structure on at least a part of a surface in contact with the substrate, and the pressure P1 while maintaining this holding Forming a joined body in which the substrate is fixed to the holding plate by exposing to a higher atmospheric pressure P2, and in the subsequent solar cell manufacturing process, the joined body is placed in a pressure atmosphere of the pressure P2 or higher. A method of manufacturing a solar cell that processes or processes a solar cell substrate of a joined body as a pseudo substrate in which a holding plate and a solar cell substrate are integrated, or transports the joined body, and is in a pressure atmosphere equal to or higher than the pressure P2. In the first step, the bonded body is a pseudo substrate in which the holding plate and the solar cell substrate are integrated, and after the first processing step, the solar cell substrate is detached from the holding plate, The battery substrate is lower than atmospheric pressure on a second processing holding plate made of a material different from that used in the first processing step in which a concave structure is formed on at least a part of a surface in contact with the substrate. A process of holding in an atmosphere of pressure P1 and exposure to an atmospheric pressure P2 higher than the pressure P1 while maintaining this holding form a bonded body in which the substrate is fixed to the holding plate for the second processing. And a step of performing the second treatment as a pseudo substrate in which the second treatment holding plate and the solar cell substrate are integrated in a pressure atmosphere of the pressure P2 or higher. A method for manufacturing a solar cell.
Claim 2:
The first processing step or the second processing step includes a step of performing wet cleaning as a pseudo substrate in which a holding plate and a solar cell substrate are integrated in a pressure atmosphere of the pressure P2 or higher. A method for producing a solar cell according to claim 1.
Claim 3:
The first treatment step or the second treatment step includes a step of heat-treating the joined body as a pseudo substrate in which a holding plate and a solar cell substrate are integrated in a pressure atmosphere of the pressure P2 or more. The manufacturing method of the solar cell of Claim 1.
Claim 4:
The method for manufacturing a solar cell according to claim 3, wherein at least a surface of the holding plate for heat treatment is formed of a material selected from silicon oxide, silicon carbide, and silicon nitride.
Claim 5 :
As the first processing step or the second processing step , a plurality of the joined bodies are vertically filled in a cassette or a boat as a pseudo substrate in which a holding plate and a solar cell substrate are integrated in a pressure atmosphere of the pressure P2 or higher. and then transported, for producing a solar cell according to any one of claims 1-4, characterized in that simultaneously process a plurality of conjugates that the filling.
Claim 6 :
Furthermore, the manufacturing method of the solar cell of any one of Claims 1-5 which has the process of canceling | releasing the said fixation in the atmosphere below the said pressure P1, and detach | detaching a solar cell board | substrate from a holding plate.
Claim 7 :
Concave structure of the holding plate, photovoltaic cell manufacturing method according to any one of claims 1-6 having the configuration formed narrower than the maximum width the width of the opening of the concave structure in the depth direction.
Claim 8 :
Process for producing a solar cell according to any one of claims 1 to 7 the thickness of the solar cell substrate is 50 to 100 [mu] m.

  In order to manufacture a solar cell at low cost, it is necessary to reduce the raw material cost by thinning the substrate of the solar cell. However, since the mechanical strength of the substrate decreases as the thickness is reduced, it is likely to be damaged if the substrate itself is transported or processed, and if the thickness is further reduced, the shape of the substrate itself cannot be maintained. Although there is a problem that it is difficult to apply the existing solar cell manufacturing process, according to the present invention, the substrate of the solar cell is adsorbed and fixed to the holding plate, and the strength of the substrate is supplemented and the adsorption is maintained. The substrate can be transported and processed as it is, and even a thin substrate having a thickness of about 50 μm can be transported, processed and processed stably, and the cost of the solar cell can be reduced.

It is sectional drawing which shows the holding method of the solar cell board | substrate of a prior art. It is sectional drawing which shows one Example of the holding plate for solar cell substrates of this invention. It is the schematic explaining an example of the holding method of the solar cell substrate by this invention, (a) is the state which has arrange | positioned the board | substrate and the holding plate under atmospheric pressure, (b) is the state which pressure-reduced the inside of the chamber to the pressure P1, (C) shows a state where the substrate is held on the holding plate under the pressure P1, and (d) shows a state where the pressure is increased to the pressure P2 in this state to form a joined body. (A)-(c) is a partially abbreviate | omitted sectional drawing which shows the different aspect of the holding | maintenance board for solar cell substrates, respectively. (A)-(c) is a top view which shows another aspect from which the holding plate for solar cell substrates differs, respectively.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
FIG. 2 shows a solar cell substrate holding plate 1 according to an embodiment of the present invention. The holding plate 1 has a large number of concave structures (recesses) on the contact surface 3 of the holding plate body 2 with the solar cell substrate 10. 4 is formed.
When the solar cell substrate 10 is held using the holding plate 1 and is transported, processed, or processed, first, as shown in FIG. The holding plate 1 to which the structure 4 is applied is arranged apart.
Next, as shown in FIG.3 (b), the inside of the chamber 20 is pressure-reduced to the pressure P1 lower than atmospheric pressure with a vacuum pump.
When the pressure reaches P1, the substrate 10 and the holding plate 1 are arranged at predetermined positions as shown in FIG.

  Next, as shown in FIG. 3D, the atmospheric pressure is increased to a pressure P2 higher than P1 while keeping the contact between the substrate 10 and the holding plate 1. However, at this time, since the pressure in the concave structure 4 is hermetically sealed by the substrate 10 and the holding plate 1 and kept at P1, the substrate 10 is attracted and fixed to the holding plate 1 by the differential pressure P2-P1. As a result, a joined body 30 in which the substrate 10 is integrated with the holding plate 1 is formed, and the joined body 30 is transported and fixed to the holding plate 1 and integrated in the pressure atmosphere of the pressure P2 or higher. Can be processed and processed without falling off the holding plate 1.

  Note that atmospheric pressure may be introduced for the pressure increase, and when a certain process is subsequently performed on the substrate, a process gas of a desired process may be used.

According to the present invention, various processes can be performed as a pseudo substrate in which a holding plate and a solar cell substrate fixed to the holding plate are integrated. Therefore, the value of the pressure P1 should be optimized by the solar cell process, but as a guideline, it should be 1/10 or less of the atmospheric pressure in the process (that is, the pressure P2).
It is desirable that the material of the holding plate has a certain degree of rigidity, and at the same time, it is selectively used depending on each manufacturing process of the solar cell.

For example, wet cleaning using chemicals may use a resin or quartz having high chemical resistance, and ceramics having high heat resistance can be used for firing heat treatment of a sinterable metal paste.
However, in order to obtain high solar cell characteristics, it is necessary to suppress impurity contamination particularly in a high temperature process. Therefore, it is preferable to use quartz (silicon oxide), silicon carbide, silicon nitride, or a combination thereof. These may be processed into a holding material by processing a bulk material, but may be applied as a coating material to a relatively inexpensive ceramic substrate or metal substrate, for example, depending on the cost and the applied process.

  The concave structure may be formed by a processing method suitable for the base material of the holding plate, and is not particularly limited. For example, in the case of metal, a method of mechanically grinding the surface can be applied. However, the contact surface with the substrate needs to be flat, and it is necessary to remove deformation and foreign matter during processing. In addition, when using ceramics or the like as the base material, a molding method using a mold, a press method, or the like can be applied.

  As shown in FIG. 4A, the cross section of the concave structure can adsorb the substrate even if the opening width 4a is equal to or wider than the maximum groove width 4b, but preferably as shown in FIG. 4B. Furthermore, it is better that the opening width 4a is narrower than the maximum groove width 4b. By adopting such a structure, it becomes possible to increase the capacity of the concave structure and keep the differential pressure for substrate adsorption more stable.

  The concave structure as shown in FIG. 4B can be formed, for example, by forming a pattern mask on the holding plate and exposing the concave structure forming portion to perform etching.

Alternatively, as shown in FIG. 4C, the concave structure 4 may be formed on the holding plate main body 2 by cutting or the like, and the plate 5 having the opening width 4a narrower than the groove width 4b may be bonded thereon.
The shape of the holding plate may be a shape suitable for the size and shape of the substrate.

  Various patterns of the concave structure can be applied. FIG. 5 is a view of a square holding plate as seen from the substrate support surface side as an example. The pattern of the concave structure may be a concentric pattern as shown in FIG. 5A, a lattice pattern as shown in FIG. 5B, or a point pattern as shown in FIG.

  In order to remove the substrate from the holding plate, the substrate and the holding plate are put into the chamber again, and the pressure is set to P1 or less. Thereby, the suction force due to the concave structure is eliminated, and the substrate can be removed from the holding plate. The substrate may be removed with, for example, a suction cup or a weakly viscous adhesive pad.

  Here, when the substrate is transferred to another holding plate and the next process is performed, the pressure in the chamber is set to a pressure suitable for the next process while keeping the substrate separated from the holding plate. The substrate is fixed to the holding plate for the next process by the procedure.

DESCRIPTION OF SYMBOLS 1 Solar cell board | substrate holding plate 2 Holding board main body 3 Contact surface with the solar cell board | substrate of a holding plate 4 Concave structure 4a Opening width 4b of a concave structure 5 Maximum width | variety in the depth direction of a concave structure Chamber 30 joined body

Claims (8)

A step of holding the solar cell substrate in an atmosphere of a pressure P1 lower than atmospheric pressure on a holding plate having a concave structure on at least a part of a surface in contact with the substrate, and the pressure P1 while maintaining this holding Forming a joined body in which the substrate is fixed to the holding plate by exposing to a higher atmospheric pressure P2, and in the subsequent solar cell manufacturing process, the joined body is placed in a pressure atmosphere of the pressure P2 or higher. A method of manufacturing a solar cell that processes or processes a solar cell substrate of a joined body as a pseudo substrate in which a holding plate and a solar cell substrate are integrated, or transports the joined body, and is in a pressure atmosphere equal to or higher than the pressure P2. In the first step, the bonded body is a pseudo substrate in which the holding plate and the solar cell substrate are integrated, and after the first processing step, the solar cell substrate is detached from the holding plate, The battery substrate is lower than atmospheric pressure on a second processing holding plate made of a material different from that used in the first processing step in which a concave structure is formed on at least a part of a surface in contact with the substrate. A process of holding in an atmosphere of pressure P1 and exposure to an atmospheric pressure P2 higher than the pressure P1 while maintaining this holding form a bonded body in which the substrate is fixed to the holding plate for the second processing. And a step of performing the second treatment as a pseudo substrate in which the second treatment holding plate and the solar cell substrate are integrated in a pressure atmosphere of the pressure P2 or higher. A method for manufacturing a solar cell. The first processing step or the second processing step includes a step of performing wet cleaning as a pseudo substrate in which a holding plate and a solar cell substrate are integrated in a pressure atmosphere of the pressure P2 or higher. A method for producing a solar cell according to claim 1. The first treatment step or the second treatment step includes a step of heat-treating the joined body as a pseudo substrate in which a holding plate and a solar cell substrate are integrated in a pressure atmosphere of the pressure P2 or more. The manufacturing method of the solar cell of Claim 1.   The method for manufacturing a solar cell according to claim 3, wherein at least a surface of the holding plate for heat treatment is formed of a material selected from silicon oxide, silicon carbide, and silicon nitride. As the first processing step or the second processing step , a plurality of the joined bodies are vertically filled in a cassette or a boat as a pseudo substrate in which a holding plate and a solar cell substrate are integrated in a pressure atmosphere of the pressure P2 or higher. and then transported, for producing a solar cell according to any one of claims 1-4, characterized in that simultaneously process a plurality of conjugates that the filling. Furthermore, the manufacturing method of the solar cell of any one of Claims 1-5 which has the process of canceling | releasing the said fixation in the atmosphere below the said pressure P1, and detach | detaching a solar cell board | substrate from a holding plate. Concave structure of the holding plate, photovoltaic cell manufacturing method according to any one of claims 1-6 having the configuration formed narrower than the maximum width the width of the opening of the concave structure in the depth direction. Process for producing a solar cell according to any one of claims 1 to 7 the thickness of the solar cell substrate is 50 to 100 [mu] m.

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