WO2004003264A1

WO2004003264A1 - Thin sheet manufacturing method, and thin sheet manufacturing apparatus

Info

Publication number: WO2004003264A1
Application number: PCT/JP2003/008056
Authority: WO
Inventors: Shuji Goma; Hirozumi Gokaku; Kozaburo Yano
Original assignee: Sharp Kabushiki Kaisha
Priority date: 2002-06-28
Filing date: 2003-06-25
Publication date: 2004-01-08
Also published as: JPWO2004003264A1; TWI234592B; AU2003244062A1; TW200407469A; JP4105158B2

Abstract

A thin sheet manufacturing method with very high manufacturing efficiency and at a revolutionarily low manufacturing cost per unit area both achieved by expanding the production scale and a thin sheet manufacturing apparatus. A silicon thin sheet (1) is manufactured by the process including a dipping step in which the surface portion of a base sheet (2) is dipped in a silicon melt (10), and silicon is made to adhere to the surface of the base sheet. After the silicon thin sheet (1) formed on the surface (2a) of the base sheet (2) is separated from the base sheet, at least the peripheral portion (4) of the silicon thin sheet (1) is cut. Since a high-quality silicon thin sheet can be manufactured at a high efficiency, the manufacturing cost can be lowered.

Description

Description Sheet manufacturing method and sheet manufacturing apparatus

The present invention relates to a thin plate manufacturing method and a thin plate manufacturing apparatus, and more particularly, to a silicon thin plate manufacturing method and a silicon thin sheet manufacturing apparatus. Background art

Silicon is used for consumer solar cells. The conversion efficiency of silicon decreases in the order of single crystal, polycrystal, and amorphous, but on the other hand, the cost is lower and the area is easier to increase. Among these, amorphous silicon, the _{S i H 4 CVD (Chemical Vapor} Deposition) method as a raw material, glass, plastic, inexpensive because it can be deposited on such a metal substrate, and tends to a large area . The conversion efficiency is up to about 12%. .

In addition, single-crystal silicon can be produced in diameters of 150 mm (6 inches) or 200 mm (8 inches) by the CZ (Czochralski) method, and it can be made larger, with a conversion efficiency of 15%. Can be exceeded.

For polycrystalline silicon, various manufacturing methods are being studied using sheet glass manufacturing technology and the like. Polycrystalline silicon tends to have a large area like amorphous silicon, but the conversion efficiency is located between monocrystalline silicon and amorphous silicon.

The various silicon manufacturing methods described above have resulted in larger areas, higher conversion efficiencies, and lower manufacturing costs. However, compared to current large-scale power generation methods such as nuclear power and thermal power generation, the unit cost of power generation is considerably higher, and it is necessary to reduce manufacturing costs. Disclosure of the invention

The present invention provides a thin plate manufacturing method and a thin plate manufacturing method that can greatly increase the manufacturing efficiency by expanding the production scale and can drastically reduce the manufacturing cost per unit area. It is an object of the present invention to provide a thin plate manufacturing apparatus.

The thin plate manufacturing method of the present invention is a method of manufacturing a thin plate by immersing a surface layer of a base plate in a melt and attaching the thin plate to the surface of the base plate. In this manufacturing method, after the thin plate formed on the surface of the base plate is separated from the base plate, at least the peripheral edge of the thin plate is cut.

By this method, a burr portion on the peripheral edge of the thin plate generated on the side surface of the base plate can be removed, and a flat thin plate can be obtained. At least means that apart from the removal of the burr part, a cutting of the molding to the product dimensions may be performed. After separation from the base plate, the forming of the thin plate may be cut so as to have a predetermined size. That is, the removal of the peripheral portion may be performed simultaneously with the cutting of the molding, or the cutting of the molding may be performed regardless of the removal of the peripheral portion. In the case where the removal of the peripheral portion is performed simultaneously with the cutting of the forming, a thin plate formed in one step can be obtained.

In the above, the molding is cut so that multiple thin plates, such as two or three, are removed from the thin plate excluding burrs. By cutting the molding, for example, a silicon thin plate for a solar cell can be efficiently obtained.

It is desirable that the above-mentioned cut peripheral portion is collected and used as a raw material of the silicon melt, and the production cost can be reduced.

It is preferable to carry out a shape inspection on all or the thin sheets whose peripheral edge is cut. For example, by inspecting a silicon thin plate and passing a passing product to the next step, for example, the processing man-hour in a later solar cell manufacturing process is not wasted.

In the above-described shape inspection, at least one of surface waviness, surface roughness, thickness, and thickness distribution of the thin plate can be inspected.

The above inspection makes it possible, for example, to check the shape of a silicon thin plate that governs the performance of a solar cell.

It is preferable to conduct a mechanical strength test on all the thin sheets whose peripheral edges have been cut out or withdrawn. For example, by conducting a test on a silicon thin plate and passing a passed product to the next process, for example, a processing step in a later solar cell manufacturing process No wasted numbers.

After the above-described immersion treatment, the thin plate formed on the crystal growth surface of the base plate is preferably transported in an attitude above the base plate. With this method, it is possible to prevent the thin plate from falling off the base plate.

When cutting at least the peripheral portion of the above-mentioned thin plate, it is preferable that the thin plate is placed on a flat surface with the free surface during growth of the thin plate facing upward, and cut. As described above, the cutting yield can be improved by turning the free surface upward when growing a thin plate.

The thin sheet manufacturing apparatus of the present invention is a thin sheet manufacturing apparatus for manufacturing a thin plate by immersing a surface layer portion of a base plate in a melt and attaching the thin plate to the surface of the base plate. The apparatus for manufacturing a thin plate includes a separating device for separating a thin plate adhered to the base plate from the base plate, and a cutting device for cutting at least a peripheral portion of the thin plate separated from the base plate. With this configuration, it is possible to supply a thin plate that can be incorporated into a solar cell or the like and exhibit sufficient performance.

Further, an inspection device for inspecting the shape of the thin plate may be provided.

For this reason, for example, the thin sheet can be sent to the next process while checking the quality of the silicon sheet. For this reason, it is possible to avoid a situation in which the performance of a silicon thin plate is inferior after being assembled into a solar cell.

It is also desirable to provide a strength test device for testing the mechanical strength of the thin plate.

With this configuration, it is possible to detect, for example, a fragile portion or the like existing in the silicon thin plate without appearing in the external appearance, and prevent input to the next process. BRIEF DESCRIPTION OF THE FIGURES

1A and 1B are diagrams illustrating an example of an apparatus of an immersion mechanism according to an embodiment of the present invention. FIG. 1A is a layout view, and FIG. 1B is a perspective view of the immersion mechanism. .

2A and 2B are diagrams showing a device of another immersion mechanism according to the embodiment of the present invention, FIG. 2A is a diagram showing an elevating operation for immersion, and FIG. It is a figure which shows the attitude | position which mounted the silicon thin plate adhered by the mechanism on the pedestal. FIG. 3 is a diagram showing a thin plate manufacturing process according to the embodiment of the present invention.

FIG. 4 is a diagram showing a base plate discriminating apparatus in the thin plate manufacturing process of FIG.

FIG. 5 is a diagram showing a silicon thin plate formed on the surface of the base plate.

FIG. 6 is a diagram of a process of separating a silicon thin plate from a base plate.

FIG. 7 is a view showing a state in which the end of the silicon thin plate is cut.

8A and 8B are views showing a method of cutting the edge of the silicon thin plate, FIG. 8A is a perspective view, and FIG. 8B is a sectional view.

FIG. 9 is a view showing the XY stage in a state where no silicon thin plate is provided. FIG. 10 is a diagram showing a process of transferring a silicon thin plate whose end has been removed.

FIG. 11 is a diagram illustrating a method of cutting out four silicon thin plates from one silicon thin plate.

FIG. 12 is a diagram of a process of inspecting a silicon thin plate from which an end has been removed.

FIG. 13 is a diagram showing another device of the immersion mechanism in the embodiment of the present invention.

FIG. 14 is a view illustrating still another device of the immersion mechanism in the embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Next, embodiments of the present invention will be described with reference to the drawings. 1A and 1B are diagrams illustrating a thin plate manufacturing apparatus according to an embodiment of the present invention. The thin plate manufacturing apparatus shown in FIG. 1A has a main chamber 61 in which a crucible 9 is arranged, and two sub-chambers 63 and 64 provided continuously in the main chamber. The silicon melt 10 is stored in the crucible 9 of the main chamber 61, and an immersion mechanism 70 for immersing the surface layer of the base plate 2 in the silicon melt 10 is arranged. An inert gas is introduced into the main chamber and maintained at a pressure slightly lower than atmospheric pressure, that is, a negative pressure. 1A and 1B, Ar gas is introduced and the pressure is set to 70 O Torr.

The sub-chamber 63 is a charging sub-chamber for loading the base plate. The sub-chamber 64 is a take-out sub-chamber for taking out the base plate 2 to which the silicon is attached from the main chamber 61. The loading sub-chamber and the unloading sub-chamber should be located so as to face each other with the crucible 9 therebetween. This simplifies the flow of the base plate. It is not necessary to face each other with a crucible. Thereafter, depending on the configuration and shape of the immersion mechanism to be described, the two sub-chambers may be arranged on the same wall side of the main chamber. In this case, it is not necessary to provide two sub-chambers, and one sub-chamber may be provided with a carry-in line and a carry-out line. The atmosphere in the sub-chamber is the same as that in the main chamber, that is, the atmosphere is inert gas and has a negative pressure.

Next, a method of manufacturing a thin plate will be described. When the main chamber 6 1 is in operation, the airtight door 8 1 is opened with the airtight door 8 3 between the sub chamber 6 3 and the main chamber 6 1 closed, and the base plate 2 is moved to the sub chamber 6 3 Carry in. Next, the airtight door 81 is closed, and the atmosphere of the sub chamber 63 is made the same as that of the main chamber 61. Thereafter, according to the operation of the immersion mechanism in the main room, the hermetic door 83 between the main room and the main room is opened, and the base plate 2 is inserted into the main room 61.

In the main room 61, the immersion mechanism 70 grasps the base plate 2 and transfers it onto the crucible 9. Next, the base plate is lowered, and the surface layer of the base plate is immersed in a silicon melt 10 to adhere a silicon layer to the surface of the base plate. Thereafter, the base plate 2 on which the silicon is adhered rises and leaves the crucible 9. During this time, the attached silicon is naturally cooled, a solid phase grows, and a predetermined silicon thin plate 1 is formed.

It is desirable that the base plate is rotated by some rotating mechanism while the silicon base plate is attached so that the silicon thin plate formed by attaching to the base plate is transported while being mounted on the base plate.

The base plate 2 on which the silicon thin plate 1 is formed is airtightly opened after confirming that the airtight door 8 1 of the sub chamber 6 4 is closed. The atmosphere in the sub-chamber 64 is controlled so as to be the same as the atmosphere in the main chamber 61. Thereafter, the base plate on which the silicon thin plate is formed is sealed with an airtight door 8. With the 3 closed, open the airtight door 81 and carry it out.To cool the silicon thin plate formed on the surface of the base plate, the main chamber 61, sub chamber 64, or outside At least one cooling device for accelerating the cooling may be provided, and the cooling device may be used to cool the silicon-adhered base plate.

Any transport mechanism may be used as the immersion mechanism 70 for transporting the base plate in the main chamber and immersing it in the silicon melt 1 °.

In the thin plate manufacturing apparatus shown in FIG. 1B, the support plate 56 is run along the rail 52, Perform horizontal transfer. The transfer in the vertical direction is performed by raising and lowering a lifting device 53 that supports the reynole 52 and moves up and down along the pole.

The base plate 2 is attached to a pedestal 51 connected to a support plate 56 by a rod 58, and moves as the support plate 56 runs on the rail 52. The horizontal movement is stopped on the silicon melt 10 in the crucible 9 and the elevating device 53 descends, so that the support plate 56, the rod 58, the pedestal 51, and the base plate 2 are moved together with the rail 52. It descends, and the surface layer of the base plate is immersed in the silicon melt. As a result, silicon adheres to the surface of the base plate. Thereafter, the elevating device 53 ascends and the base plate separates from the silicon melt. Furthermore, after the above-mentioned ascent, horizontal movement is made, and the base plate on which the silicon is adhered is removed from the pedestal at a position away from the crucible. Since the silicon melt is at a high temperature of 140 to 150 ° C and silicon is deposited, the heat insulating shield plate 57 is placed on the crucible to protect the immersion mechanism such as rails. To place.

2A and 2B are diagrams showing another immersion mechanism different from the above immersion mechanism. The base plate 2 is held by a pedestal 51 and connected to a drive mechanism 76. The drive mechanism 76 has a rotary motion mechanism that not only moves along the axis 72 but also rotates by itself. When the base plate is immersed in the silicon melt in the crucible, the elevating drive mechanism 73 lowers the drive mechanism 76 and the base plate 2 including the shaft 72 together and melts the silicon plate on the base plate. By attaching the liquid, the silicon thin plate 1 can be manufactured.

After the silicon melt is applied and the silicon thin plate 1 is formed, during transfer, the driving mechanism 76 rotates as shown in Figure 2B, and the silicon thin plate 1 is placed on the ground plate 2 Take. With this position, even if the adhesive force of the silicon thin plate is reduced, the silicon thin plate can be prevented from detaching from the base plate 2 and dropping. Again, any mechanism for rotating the pedestal may be used as long as the base plate can move with a thin silicon plate placed on it during transfer.

Next, processing steps of the base plate and the silicon thin plate, which are features of the present invention, will be described. In FIG. 3, a silicon thin plate manufactured by the thin plate manufacturing apparatus is transferred to a cooling process while being attached to a carbon base plate. The silicon thin plate and the lower plate cooled in the cooling step are separated by a thin plate separating device.

The base plate separated from the silicon thin plate is transferred to the base plate determination process, Is determined. The three types of judgment are: (al) can be used again for immersion treatment, (a 2) processing is required before use for immersion treatment, and (a 3) is disposed of It is a judgment. The height of the ridges on the surface of the carbon base plate immersed in the silicon melt decreases as the number of immersion treatments increases. If the height of the ridges is reduced, a high-quality silicon sheet with a uniform thickness cannot be formed. Further, as the number of uses increases, a hole-shaped concave portion is formed on the surface of the base plate. These hole-shaped recesses also deteriorate the surface properties of the silicon thin plate.

The determination that processing was necessary before use in the immersion treatment in (a2) was made by forming ridges and depressions of a predetermined height again on the surface of the base plate and cutting to remove the pits. It means that processing must be performed. New ridge-like irregularities are formed on the surface of the base plate by cutting, and the thickness is reduced by cutting. In the case where the thickness is reduced within a predetermined range, a silicon thin plate can be manufactured without any trouble by modifying the trajectory of dipping the base plate in the silicon melt. At this time, usually, the horizontal movement command, the vertical movement movement command, and the tilt movement command are each programmed by a personal computer, and transmitted to the controller, thereby realizing an arbitrary trajectory according to the program. I do. One motor is assigned to each of the horizontal movement, the vertical movement, and the tilt movement described above, and each is individually driven by a total of three motors. The above-mentioned program is used to obtain a silicon thin plate with a predetermined thickness corresponding to (si) fluctuations in the liquid level of the melt and (s 2) fluctuations in the thickness of the base plate. Control movement (movement).

The disposal in (a3) refers to a base plate whose thickness has decreased beyond the processing limit as a result of repeating the above cutting process. There is no room for cutting such a base plate, so it is discarded. The discarded base plate is replenished by adding a new base plate.

FIG. 4 is a diagram showing a base plate discriminating apparatus used in the base plate discriminating step. In FIG. 4, the base plate 2 from which the silicon thin plate has been separated is sequentially fed from the back to the near side. The base plate that has been fed forward is measured by the surface state measurement unit 11 and the side surface state measurement unit 12 first. The surface condition measurement unit 11 observes the height of the ridge-shaped irregularities on the crystal growth surface of the base plate, the hole-shaped concave portions, etc. In addition, the shape of the crystal growth surface is measured. The side surface measurement unit 12 measures the thickness of the base plate and reads the identification mark and the usage history marking formed on the side surface. The surface properties, shape, thickness, markings, etc. of the crystal growth surface are sent to the base plate management PC 14 via the base plate information transmission path 16. The base board management PC 14 ascertains the state and use history of the target base board, and based on the information, determines which of the above judgments (al), (a2), and (a3) Is determined.

The content of this determination is sent to the sorting device 15 via the determination transmission path 17. The sorting device 15 sorts the target base plate to a transfer path corresponding to the determination. Also, the marking information is sent from the base plate management PC 14 to the marking device 13 via the marking information transmission path 18. The marking device 13 performs marking on the side surface of the base plate based on the marking information. The marking may be of any shape. For example, there is a method of engraving each time a character or symbol is used.

Further, the base plate may be provided with an identification mark for identifying itself. As the identification mark, an identification mark unique to the base plate, which differs for each base plate, may be used, or a lot of base plates may be used as one lot and a lot identification mark may be used. By having the identification mark on the base plate, the use history central management of the base plate can be more accurately managed, and the marking need only be performed once before use. The shape of the identification mark may be any shape. For example, there is a method of engraving characters, symbols, serial numbers, bar codes, etc.

The above marking is desirably made on a surface other than the surface on which the thin plate is grown, specifically on the side surface or the back surface. However, depending on the mark shape, it is also possible to mark the growth surface. In this case, the mark is transferred to the thin plate, and it is possible to grasp the used base plate or its history just by looking at the thin plate. The above marking makes it possible to reconsider the usage history even when an unexpected situation occurs and the identity of the base plate is confused.

With the above-mentioned base plate reuse system, it is possible to manufacture a silicon thin plate of a certain level or higher while maintaining a high yield while reusing the base plate. Next, the silicon thin plate will be described. In FIG. 3, the silicon thin plate separated from the base plate by the thin plate separating device is transferred to the edge cutting device, where the flash at the end is cut. The burrs at the end are used as a raw material for silicon melt as broken material. Also, the silicon thin plate of the product part whose end has been removed is transferred to the thin plate inspection process, where it is inspected, and passed products are put into the solar cell manufacturing process. Rejected products are considered to be broken materials and used as raw materials for silicon melts. Next, the step of cutting the edge of the silicon thin plate will be described. FIG. 5 is a view showing a state where the silicon thin plate 1 is formed on the crystal growth surface of the base plate 2. The uppermost surface of the silicon thin plate is the surface that was in contact with the silicon melt to the end when the silicon adhered, and is the free surface la. Silicon is formed not only on one surface of the base plate, but also on the surrounding side surfaces. The side part is an end beam. Next, as shown in FIG. 6, the silicon thin plate 1 is lifted up by the vacuum suction device 3 to be separated from the base plate 2. The crystal growth surface 2a of the base plate is separated from the silicon thin plate. Next, as shown in FIG. 7, the end 4 of the square silicon thin plate is cut off by a cutting portion 29 to obtain a silicon thin plate 5 as a product.

The step of cutting the end will be described in detail with reference to FIGS. 8A and 8B. FIG. 8A is a perspective view of a silicon thin plate placed on the suction stage 25 of the end cutting device, and FIG. 8B is a schematic sectional view thereof. The end beam is cut along the dotted line in FIG. 8A. The silicon thin plate shown in FIGS. 8A and 8B includes an end burr 4, and the silicon thin plate is placed on the suction stage 25 of the end cutting device with the free surface 1a on the top side. I have. FIG. 9 is a diagram showing the XY stage where no silicon thin plate is placed. As shown in FIG. 9, the suction stage is integrated with the XY stage 23. The outer shape of the suction stage is higher than the height of the end beam, smaller than the inner circumference of the end beam, and larger than the four rounds of cutting the thin silicon plate. Therefore, when the silicon thin plate is fixed to the suction stage, the end burrs do not interfere with the XY stage 23 and the suction stage.

8A and 8B, the silicon thin plate 1 with the burrs at the ends is mounted on the XY stage 23. FIG. The silicon thin plate 1 is cut at its end by a laser beam 21 emitted from a cutting unit 22 while operating an XY table. FIG. 10 is a diagram showing the silicon thin plate after the end is cut. Products and The silicon thin plate 5 is pulled up by the vacuum suction device 24 and transferred to a predetermined processing step. The burrs 4 at the end are used as a raw material for silicon melt. The cutting step of forming one silicon thin plate separated from one base plate into four silicon thin plates will be described with reference to FIG. In this case, the laser beam 21 emitted from the cutting unit 2'2 is used while scanning the XY stage 23 using the same end cutting device as that shown in FIGS. 8A and 8B. In the same process as the cutting in step 4, it is molded into four thin silicon plates. After molding, each of the four silicon thin plates is pulled up by a vacuum suction device and transferred to a predetermined processing step in the same manner as in FIG.

As another embodiment, the above cutting may be performed by scanning the laser beam 21 emitted from the cutting unit 22.

In another embodiment, the cutting of the end portion and the cutting of the molding may be performed using different cutting devices. In this case, the tact time required for cutting can be reduced as compared with using one cutting device.

The means for cutting the silicon thin plate is not limited to a laser, and a dicer, plasma cutting, electron beam cutting, or any other cutting means can be used.

FIG. 12 is a view showing an inspection process of a silicon thin plate whose end has been cut. It is assumed that the silicon thin plate 5 is sequentially fed from the left end of the figure to the right. The shape of the silicon thin plate 5 mounted on the XY stage 32 is inspected by the shape inspection unit 31. Next, the silicon thin plate 5 is transferred to a strength test unit 33, where it is subjected to a predetermined bending stress and subjected to a test to determine whether it will be broken. Since this strength test is a destructive test, it is preferable that only a predetermined number of silicon thin plates be extracted from one lot and tested. In addition, in the case of a normal silicon thin plate, a 100% test may be used as long as the test applies a bending stress that does not cause crushing. The results of these shape inspection and strength test are both sent to the sheet management PC 35 via the information transmission path 36. The thin plate management PC 35 determines pass / fail based on the above inspection result, and transmits the result to the pass / fail sorting device 34 via the pass / fail determination transmission path 37. The pass / fail sorting device 34 sorts the target silicon thin plate to the transfer path corresponding to the judgment based on the pass / fail judgment. FIGS. 13 and 14 show examples of a thin plate manufacturing apparatus. In the immersion mechanism shown in FIG. 13, a support plate 56 having a guide hole runs along the rail 52. The lifting rails 54 and 55 form a shallow U-shaped orbit on the crucible so that the pedestal approaches the silicon melt on the silicon melt 10. The upper end of the rod 58 is freely mounted on the rails 54, 55.

The base plate 2 is mounted on the pedestal 51 and run along the rails 52, 54, 55. When approaching the crucible, the rails 54 and 55 draw a smooth arc and follow a trajectory approaching the silicon melt 10. At this time, the rod approaches the silicon melt through the guide hole formed in the support plate 56, and as a result, the surface layer of the base plate 2 is immersed in the silicon melt. After this, the rails 54, 55 take an ascending trajectory. The subsequent movement is the same as in FIG. 1B.

In the thin plate manufacturing apparatus shown in FIG. 14, the base plate 2 is attached to a base plate coupler 42 arranged around the rotation axis 41. The base plate coupler moves according to the rotation of the rotating shaft 41. By bringing the rotating shaft 41 closer to the silicon melt while intermittently rotating the rotating shaft, a silicon thin plate is formed on the surface of the base plate 2.

(Example)

Next, examples will be described.

Example 1

In Example 1, the number of times the base plate was used was investigated. That is, a thin plate manufactured using a carbon base plate immersed in a silicon melt a predetermined number of times was inspected by the method shown in FIG. 12 to determine pass / fail.

In this example, after the thin plate was removed from the base plate and cut, a shape inspection was performed to check the surface undulation, thickness, and thickness distribution. For surface waviness, the passing criterion was that the maximum filtered waviness defined by JISB 0601-1994 be less than or equal to 300 μπι. For the thickness and thickness distribution, the acceptance criteria were that the thickness of the entire plate was 350 μm ± 50 m. Sheets that did not reach the inspection process due to poor sheet growth, dropping, cracking, or chipping were counted as rejected. Table 1 shows the results. Number of times of base plate use 1 time 10 times 50 times 100 times 500 times 1000 times

98% 98% 98% 98% 97% 83% According to Table 1, the pass rate of silicon substrate is 97% even after 500 times use. Therefore, it was confirmed that most of the base plate could be used about 500 times.

Example 2

In Example 2, the number of times of cutting the base plate and the change in the thickness of the base plate were investigated. Table 2 shows the thickness of the base plate according to the number of times of cutting and the progress of the thin plate inspection results. The method of inspecting a thin plate is the same as in Example 1.

Table 2

According to Table 2, the thickness of the base plate decreases as the number of cutting operations increases. The rate of reduction can be estimated to be 2 mm in thickness per cut. Conversely, it can be said that the cutting allowance per cutting is 2 mm. According to Table 2, when the trajectory is not corrected when the base plate is immersed, the pass rate of the silicon thin plate becomes 75% when the number of cutting operations is two, and the yield is considerably deteriorated. In addition, when correcting the trajectory, it was confirmed that a pass rate of 97% was maintained even after six cutting operations. In the case of eight cuttings, the thickness becomes too thin and immersion is impossible. Example 3

In Example 3, the relationship between the presence / absence of cutting of the end of the silicon thin plate, the presence / absence of inspection after cutting, and the non-defective product ratio was investigated.

The inspection method after cutting is the same as in Example 1.

Next, an example of a solar cell manufacturing process will be described. Wash and texture the sheet A general method was applied in the order of tuning, diffusion layer formation, oxide film removal, antireflection film formation, back etch, backside electrode formation, and light-receiving surface electrode formation. At this time, cracks in the process and thin sheets whose performance (conversion efficiency) after fabrication was less than 12% were rejected. Table 3 shows the results.

Table 3

By cutting the edge of the silicon thin plate, the product yield after the solar cell fabrication process is improved. If the edges remain, the screen during electrode printing cannot contact the surface that was in contact with the base plate, resulting in poor electrode printing and deteriorating the characteristics. Also, the overall rate of non-defective products does not change depending on the presence or absence of inspection. Also, depending on the presence or absence of the inspection, the overall non-defective rate does not change. However, the non-defective rate in the solar cell fabrication process was inferior to that without inspection. If the undulation or thickness distribution of the silicon thin plate is out of the acceptable standard, the anti-reflection film cannot be formed uniformly and the electrodes cannot be formed uniformly, which causes poor characteristics. For this reason, before conducting the solar cell fabrication process, the inspection is performed in advance and the defective silicon thin plate is removed, so that waste in subsequent steps can be reduced.

Example 4

In this example, Table 4 shows the results of investigations on the vertical relationship between the silicon thin plate and the base plate during transport immediately after the immersion treatment, and the attitude of the silicon thin plate when cutting the edge of the silicon thin plate. Table 4

Growth surface during transport: Crystal growth surface of base plate

Melt surface: Free surface of silicon sheet According to Table 4, if the sheet is placed on the lower side during transportation after immersion, the silicon sheet falls off the base sheet. For this reason, it was confirmed that dropping can be prevented by arranging the silicon thin plate on the base plate and transporting it. Also, when cutting the edge of a silicon thin plate on the XY stage, by turning the melt surface (free side) of the silicon thin plate upward, the overall non-defective rate can be greatly increased. Although the embodiments of the present invention have been described above, the embodiments of the present invention disclosed above are merely examples, and the scope of the present invention is limited to these embodiments. Never. The scope of the present invention is indicated by the description of the claims, and further includes meanings equivalent to the description of the claims and all modifications within the scope.

By using the thin plate manufacturing method and the thin plate manufacturing apparatus of the present invention, the manufacturing efficiency of the thin plate can be increased, and the manufacturing cost can be reduced. Industrial applicability

By using the thin plate manufacturing method and the thin plate manufacturing apparatus of the present invention, for example, a high quality silicon thin plate can be manufactured with high efficiency, so that the manufacturing cost can be reduced. For this reason, it is expected to be widely used in fields where cost competition with other power generation methods such as solar power generation is severe.

Claims

The scope of the claims

1. A method for producing a thin plate by immersing a surface layer of a base plate in a melt containing at least one of a metal material and a semiconductor material and attaching the thin plate to the surface of the base plate,

A method for manufacturing a thin plate, comprising: separating the thin plate formed on the surface of the base plate from the base plate; and cutting at least a peripheral portion of the thin plate.

2. The thin plate manufacturing method according to claim 1, wherein the cut peripheral portion is collected and used as a raw material of the melt.

3. The method of manufacturing a thin plate according to claim 1, wherein the cut thin plate is subjected to a shape inspection by a whole or a sampling.

4. The thin plate manufacturing method according to claim 3, wherein in the shape inspection, at least one of surface undulation, surface roughness, thickness, and thickness distribution of the thin plate is inspected.

5. The method for producing a thin plate according to claim 1, wherein a test for mechanical strength is performed on all or all of the cut thin plates.

6. The method of manufacturing a thin plate according to claim 1, wherein after the immersion treatment, the thin plate formed on the crystal growth surface of the base plate is transferred in a posture of resting on the base plate.

7. The thin plate manufacturing method according to claim 1, wherein when cutting at least a peripheral portion of the thin plate, the thin plate is placed on a flat surface with the free surface during growth of the thin plate facing upward, and cut.

8.- A method of manufacturing a thin plate by immersing a surface layer of a base plate in a melt containing at least one of a metal material and a semiconductor material and attaching the thin plate to the surface of the base plate,

A method for manufacturing a thin plate, comprising: separating the thin plate formed on the surface of the base plate from the base plate, and cutting the thin plate into a predetermined size.

9. The thin plate manufacturing method according to claim 8, wherein the cut peripheral portion is collected and used as a raw material of the melt.

10 0. For the cut thin plate, perform a shape inspection by extracting all or 9. The method for producing a thin plate according to claim 8.

11. The thin plate manufacturing method according to claim 10, wherein in the shape inspection, at least one of surface waviness, surface roughness, thickness, and thickness distribution of the thin plate is inspected.

12. The method of manufacturing a thin plate according to claim 8, wherein a test of mechanical strength is performed on all or all of the cut thin plates by pulling.

13. The method of manufacturing a thin plate according to claim 8, wherein after the immersion treatment, the thin plate formed on the crystal growth surface of the base plate is transferred in a posture of resting on the base plate.

9. The thin plate manufacturing method according to claim 8, wherein when cutting at least the peripheral portion of the thin plate, the thin plate is placed on a flat surface with the free surface during the growth of the thin plate facing upward, and cut. .

15. A thin plate manufacturing apparatus for manufacturing a thin plate by immersing a surface layer portion of a base plate in a melt and attaching the thin plate to the surface of the base plate,

A thin plate manufacturing apparatus comprising: a separating device that separates the thin plate adhered to the base plate from the base plate; and a cutting device that cuts at least a peripheral portion of the thin plate separated from the base plate.

16. The apparatus according to claim 15, further comprising an inspection device for inspecting a shape of the thin plate.

17. The thin plate manufacturing apparatus according to claim 15, further comprising a strength test device for testing a mechanical strength of the thin plate.