JP2006073849A - Manufacturing method and manufacturing device of semiconductor element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify a semiconductor element manufacturing process, to suppress materials and fuel and light expenses to be consumed in the process to a small amount, then to simplify a manufacturing device and to lower the price of it by omitting expensive devices and processes exclusive for patterning. <P>SOLUTION: The method is disclosed for performing patterning with a substrate itself as a mask by folding the end of the substrate at the time of forming a semiconductor layer on the substrate. Patterning is executed by bending the substrate end just by an auxiliary roller installed in a substrate carrier. By the manufacturing method and manufacturing device, the need of the expensive devices and processes exclusive for patterning such as a metal mask and a laser is eliminated. Also, by the simplification of a device group, equipment depreciations are reduced. Then, the manufacture cost price of a solar battery is lowered drastically as well. As a result, an inexpensive solar battery is easily manufactured. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

This is a technical field related to patterning by a mask method in semiconductor thin film deposition. The substrate is transported using a roll-to-roll method. The flexible substrate includes a resin substrate such as PET, PEN, and cellulose, a metal thin plate such as SUS, and paper. A semiconductor element manufactured using a semiconductor thin film includes a photoelectric conversion element, a solar cell, and a diode. Semiconductor thin film deposition forming methods include plasma CVD, sputtering, vapor deposition, coating, and spraying.

In order to manufacture an inexpensive solar cell, it is urgent to simplify and lower the price of the solar cell manufacturing apparatus. If the manufacturing process is simplified, the amount of materials and utility costs consumed in the process can be reduced, and the manufacturing apparatus can be simplified and reduced in price easily.

Non-single crystal silicon thin film solar cells are being developed as a kind of inexpensive solar cells. Non-single crystal silicon refers to amorphous silicon, microcrystalline silicon, and polycrystalline silicon.

FIG. 1A is a cross-sectional view of a general thin film solar cell. In the thin film solar cell, light 105 is incident from one surface of the semiconductor layer 103 to generate a potential difference 106 in the thickness direction. A transparent electrode 104 that transmits light is provided on the light incident side of the thin film semiconductor. A back electrode 102 is provided on the side opposite to the light incident side of the thin film semiconductor. Conductive wires are connected to the transparent electrode and the back electrode, respectively, and current is taken out to the outside.

However, when connecting a conductive wire to each of the transparent electrode and the back electrode, care should be taken not to contact the transparent electrode and the back electrode. Each electrode is only separated by a thin film semiconductor layer 103 having a thickness of about 1 μm and a high resistance. In particular, the back electrode cannot be directly connected because it is covered with the transparent electrode and the thin film semiconductor layer. When trying to connect to the back electrode from the transparent electrode side, special measures must be taken to prevent contact with the transparent electrode side and current leakage. For example, as shown in FIG. 1B, only the transparent electrode and the semiconductor layer are separated by an insulator 112. Moreover, as shown in FIG. 1 (3), also when connecting the conducting wire 113 to a transparent electrode, if it crimps | bonds, a semiconductor layer will be penetrated and a transparent electrode and a back electrode will contact. When the transparent electrode and the back electrode are brought into contact, the potential difference between the two electrodes is lost.

When connecting each of the transparent electrode and the back electrode to the conducting wire, it is convenient to form the transparent electrode, the back electrode, and the semiconductor layer by shifting each other as shown in FIG. A method of shifting the transparent electrode, the back electrode, and the semiconductor layer to form each shape is called patterning. In the case of an electrode formed by patterning, as shown in FIG. 1 (5), the transparent electrode and the back electrode are not contacted even when the lead wire and each electrode are pressure-bonded. And current leakage does not occur.

As a conventional patterning technique, there is a method using a mask (for example, Patent Document 1 and Patent Document 2). FIG. 2 shows a manufacturing process of a solar cell using a method using a mask. (1) First, the transparent electrode 201 is formed on the transparent substrate 211. (2) A resin 202 is printed and formed on the transparent electrode 201. (3) The transparent electrode 201 is etched. The portion of the transparent electrode 201 covered with the resin 202 remains without being etched. (4) The resin 202 is peeled off. (5) The positions of the metal mask 221 and the transparent electrode 201 are aligned. Then, a semiconductor layer 203 is deposited. A semiconductor layer 203 is deposited and formed in the opening of the metal mask 221. (6) The positions of the metal mask 222 and the semiconductor layer 203 are aligned. Then, the back electrode 204 is deposited. A back electrode 204 is deposited and formed in the opening of the metal mask 222. Patterning is completed by the steps described in (1) to (6) above.

In FIG. 2, the transparent electrode 201 is formed by patterning called a photolithography method, and the semiconductor layer 203 and the back electrode 204 are formed by patterning called a metal mask method. In patterning called a photolithography method, a printed resin serves as a mask, and a transparent electrode in a portion not covered with the mask is etched. In patterning called a metal mask method, a semiconductor layer and a back electrode layer are deposited and formed in an opening of a metal mask.

The problem of patterning with a mask is that the mask itself is difficult to manufacture and maintain. In the photography system, a resin serving as a mask, a printing plate, a printing machine, a dryer, a resin removing liquid, and the like are required. In the metal mask method, a deposited film is deposited on the metal mask and must be cleaned when a certain film thickness is reached. Moreover, when making a metal mask disposable, it is necessary to manufacture the area of a metal mask by the same area as a solar cell main body board | substrate.

Other conventional techniques for patterning include laser cutting (for example, Patent Document 3 and Patent Document 4). FIG. 3 shows a manufacturing process of a solar cell using a method by laser cutting. (1) First, the transparent electrode 301 is deposited on the transparent substrate 311. (2) The laser 321 is scanned to cut the transparent electrode 301. (3) A semiconductor layer 302 is deposited. (4) The laser 321 is scanned to cut the semiconductor layer 302. (5) A back electrode 303 is deposited. (6) The laser 321 is scanned and the back electrode 303 is cut. Patterning is completed in FIGS. 3 (1) to 3 (6).

The problem with the laser cutting method is that the laser cutting device is expensive. Laser cutting devices require a laser light source and a laser scanning mechanism. The laser scanning mechanism includes a mechanism for moving an XY stage and a laser light reflecting mirror. Laser cutting devices are complex and expensive.
JP 10-12904 JP 2001-177136 A JP-A-10-27918 JP 2000-252360 A

Simplify the solar cell manufacturing process and keep the materials and utility costs consumed in the process small. And it aims at the simplification and cost reduction of a manufacturing apparatus. Specifically, an object is to omit an expensive apparatus and process dedicated to patterning.

The method according to this patent is a method of patterning by forming a semiconductor layer on a substrate by folding the edge of the substrate and using the substrate itself as a mask. The substrate can be bent at the substrate end only by the auxiliary roller in the middle of conveyance. An expensive apparatus and process dedicated to patterning are not necessary.

First, FIG. 4 shows patterning of a method of folding the substrate end to the back side of the substrate. FIG. 4 shows a cross-sectional view of the substrate. In the substrate 401, the surface exposed in the direction in which the deposited film flies is the front surface 411, and the opposite surface is the back surface 412. FIG. 4A shows the reference state of the substrate 401. In FIG. 4A, as the first step, the substrate end a is bent to the back side at the position A. Then, the state shown in FIG. Then, the first deposited film 402 is deposited and the state shown in FIG. In the second step, the substrate end a is first returned to the reference state. Then, the state shown in FIG. Then, a second deposited film 403 is deposited. As a result, the state shown in FIG. By the method shown in FIG. 4, the first deposited film 402 can be formed between bA on the substrate 401, and the second deposited film 403 can be formed between ba.

Next, FIG. 5 shows patterning of a method of folding the substrate end to the substrate surface side. FIG. 5A shows the reference state of the substrate 501. First, the substrate 501 is bent from the state shown in FIG. 5A to the surface side at the position A so as to be in the state shown in FIG. The substrate end a overlaps with the position a 'on the substrate. Then, a first deposited film 502 is deposited and brought into the state of FIG. Next, the substrate end a is returned to the reference state of the substrate to obtain the state shown in FIG. Then, a second deposited film 503 is deposited and formed as shown in FIG. By the method shown in FIG. 5, the first deposited film 502 can be deposited between ba ′, and the second deposited film 503 can be deposited between ba.

By using the patterning of the method of folding the substrate edge shown in FIGS. 4 and 5, the production of the mask, the expensive apparatus, etc. as seen in the method using the mask and the method using the laser become unnecessary.

The patterning of the method according to this patent shows that no leakage of the solar cell output current occurs at the connection between the solar cell and the conductor. The said conducting wire is for connecting with each electrode and taking out a solar cell output outside. A general connection state between the solar cell and the conductive wire is shown in FIG. The back electrode conducting wire 611 and the transparent electrode conducting wire 612 are directly connected to the back electrode 602 and the transparent electrode 604, respectively. Next, FIG. 6B shows a state in which the conductive wires are pressure-bonded to the substrate 601 side. Even if the back surface electrode conducting wire 611 is crimped to the back surface electrode 602, the substrate 601 only exists below the electrode. When an insulator is used for the substrate 601, the electrical connection is not affected. Further, the transparent electrode 604 and the back electrode lead wire 611 are separated and do not contact each other. Therefore, the transparent electrode 604 and the back electrode 602 are not short-circuited and no leakage current is generated. The transparent electrode conducting wire 612 may break through the transparent electrode 604 and reach the semiconductor layer 603 and further the substrate 601 when pressed. However, even when it reaches, it is separated from the back electrode 602 by the high-resistance semiconductor layer 603. Compared to the thickness 621 of the semiconductor layer, the distance 622 between the back electrode 602 and the transparent electrode conductor 612 can be sufficiently long, and no leakage current is generated.

The method according to this patent is a method of patterning by forming a semiconductor layer on a substrate by folding the edge of the substrate and using the substrate itself as a mask. The manufacturing method and manufacturing apparatus according to this patent eliminates the need for expensive apparatuses and processes dedicated to patterning, such as metal masks and lasers. Patterning can be performed by bending the substrate edge only with an auxiliary roller installed in the solar cell substrate transfer device by the manufacturing method and the manufacturing apparatus of this patent. In addition, equipment depreciation can be reduced by simplifying the device group. And the manufacturing cost of solar cells can be greatly reduced. As a result, the manufacturing method and the manufacturing apparatus according to the present patent facilitate manufacture of an inexpensive solar cell.

The form of the thin-film solar cell manufactured by using the patterning method of folding the substrate end toward the back surface shown in FIG. 4 is practical.

FIG. 7 shows a method for manufacturing a thin-film solar cell using a belt-like substrate by the method according to this patent. The strip substrate is a flexible substrate. FIG. 7 shows a short side sectional view of the belt-like substrate.

The state of the substrate 701 shown in FIG. 7A is a substrate reference state. The upper surface of the substrate 701 is a substrate surface 711 and the lower surface is a back surface 712. First, the substrate right end a is folded to the back surface 712 side at the position A, and the state shown in FIG. Then, a back metal electrode 702 is formed by deposition, and the state shown in FIG. Next, the left end b of the substrate is folded toward the back surface 712 at the position B to obtain the state shown in FIG. Then, an n-type semiconductor layer 703 is deposited and formed as shown in FIG. This time, only the right edge a of the substrate is returned to the position of the reference state, and the state shown in FIG. Thereafter, i, a p-type semiconductor layer 704 and a transparent electrode 705 are deposited to form the state shown in FIG. Finally, the left end b of the substrate is returned to the position in the reference state, and the state shown in FIG. As shown in FIG. 7, the solar cell is completed by using patterning by a method in which the substrate edge is folded and the solar cell substrate itself is used as a mask.

In addition, although the thin film solar cell structure which injects light from the surface opposite to a board | substrate was shown in the present Example, when a transparent substrate is used for the board | substrate 701, you may make it the thin film solar cell structure which injects light from the board | substrate side. In this case, a transparent electrode is formed instead of the back metal electrode 702.

In this embodiment, a method for manufacturing a solar cell is shown in the order of deposition of the n-type semiconductor layer 703, i, and p-type semiconductor layer 704. However, the n-type and p-type conductivity types are interchanged, and the p-type semiconductor layer is changed to 703. The solar cell can also be produced by depositing the i and n-type semiconductor layers at the position 704.

Solar cells made by patterning the method according to this patent can be easily connected in series. A solar cell group produced by connecting the solar cells in series is shown in FIG.

Non-single-crystal silicon thin-film solar cells have an open circuit voltage of about 0.5 V to 0.9 V under sunlight, per pin junction of a semiconductor layer. In the case of outputting an optimum current, the voltage is further lowered. For this reason, there are many cases where solar cells are connected in series and used at a high output voltage as a solar cell group in practical use such as connection with a battery.

FIG. 8 shows a solar cell group in which solar cells created on a flexible substrate are connected in series. The back electrode-side extraction lead wire 831 is connected to the back electrode side of the solar cell 841 corresponding to the end of the series connection, and the transparent electrode side extraction lead wire 832 is connected to the transparent electrode side of the solar cell 843 corresponding to the other end. A connecting portion between the solar cell 841 and the solar cell 842 is connected by a fastener 821. In addition, a connection portion between the solar cell 842 and the solar cell 843 is connected by a bolt 822.
Since the fasteners 821 and the bolts 822 are given as examples, the fasteners may be used at all connection locations, or bolts may be used at all connection locations. Regarding the electrodes, the transparent electrode 804a of the solar cell 841 and the back electrode 802b of the solar cell 842 are connected at the portion connected by the fastener 821. Similarly, the transparent electrode 804b of the solar cell 842 and the back electrode 802c of the solar cell 843 are connected at the portion connected by the bolt 822.

The leakage current of the solar cell group shown in FIG. 8 will be described. Even if the fastener 821 is firmly clamped, the transparent electrode 804a and the back electrode 802a in the solar cell 841 and the transparent electrode 804b and the back electrode 802b in the solar cell 842 are not in contact with each other. That is, the potential difference generated in each solar cell is not lost, and no leakage current is generated. In addition, a connection portion between the solar cell 842 and the solar cell 843 is connected by a bolt 822. In the connection portion, the electrode layer of each solar cell, the semiconductor layer, and the substrate are connected by making holes, but the transparent electrode 804b and the back electrode 802b in the solar cell 842, and the transparent electrode 804c and the back electrode 802c in the solar cell 843 are There is no contact with each other. That is, the potential difference generated in each solar cell is not lost, and no leakage current is generated. Furthermore, stress is often applied from the outside to each lead wire portion. However, in the solar cell structure created by patterning the method according to this patent, the contact between the transparent electrode and the back electrode in each solar cell does not occur, and the output characteristics are good.

Although not shown in FIG. 8, in order to improve the weather resistance of the solar cell group, a glass plate is provided on the transparent electrode side, a moisture-proof plate is provided on the substrate side, and the solar cell is sealed with the two plates. .

A solar cell manufacturing apparatus using patterning of the method according to this patent is shown in FIG. The apparatus is an apparatus for forming a non-single crystal silicon thin film solar cell on a long flexible substrate. The substrate transport mechanism of the apparatus is a roll-to-roll system in which a strip-shaped substrate wound in a roll shape is pulled out from the roll, and the pulled-out strip-shaped substrate is wound in a roll shape. FIG. 9 is a view from the surface side of the belt-like substrate. In FIG. 9, the strip-shaped substrate unwinding device and the strip-shaped substrate winding device are omitted. The belt-like substrate is transported from the belt-like substrate carry-in side end 921 toward the belt-like substrate carry-out side end 922.

The belt-shaped substrate is transported from the belt-shaped substrate carry-in side end 921. The cross-sectional shape of the substrate at the position 931a is as shown in 931b. First, the cross-sectional shape changing roller 912 and the auxiliary rollers 911 and 913 are used to fold the right end of the substrate toward the back side of the substrate. The cross-sectional shape of the substrate at the position 932a is like 932b. Then, a back electrode aluminum thin film is formed by a back electrode forming sputtering apparatus 901. Here, the cross-sectional shape changing roller 914 is used to fold the left end of the substrate toward the back side of the substrate. The cross-sectional shape of the substrate at the position 933a is as shown in 933b. Next, an n-type non-single-crystal silicon thin film is formed on the back electrode aluminum thin film by a CVD apparatus 902 for forming a non-single-crystal silicon thin film. Here, the sectional shape changing roller 915 is used to return the folding of the right end of the substrate to the original position. The cross-sectional shape of the substrate at the position of 934a is as shown in 934b. Then, an i-type non-single-crystal silicon thin film is formed by a CVD apparatus 903 for forming a non-single-crystal silicon thin film. Similarly, a p-type non-single-crystal silicon thin film is formed by the non-single-crystal silicon thin film forming CVD apparatus 904. Further, a transparent electrode tin oxide thin film is formed by a transparent electrode forming sputtering apparatus 905. Finally, the sectional shape changing roller 916 is used to return the folding of the left end of the substrate to the original position. The substrate cross-sectional shape at the position 935a is as shown in 935b, and the strip substrate is unloaded from the strip substrate unloading side end 922, whereby the solar cell is completed.

As can be seen from the solar cell manufacturing apparatus in the present embodiment, patterning of the thin film can be performed only by devising the shape of the auxiliary roller that is a part of the substrate transport mechanism using a roll-to-roll apparatus. Furthermore, a solar cell can be manufactured over a long flexible substrate. That is, in the solar cell manufacturing apparatus using the patterning of the method according to this patent, an expensive apparatus and process dedicated to patterning are not necessary.

Since an inexpensive solar cell manufacturing apparatus can be provided, the economic effect is great in the capital investment of solar cells.

Cross section of a general thin film solar cell Conventional patterning and masking methods Conventional patterning technology, laser cutting method Patterning the method of folding the substrate edge to the back side of the substrate Patterning the method of folding the substrate edge to the substrate surface side Leakage of solar cell output current at the connection between solar cell and conductor Method for forming a thin film solar cell on a substrate using the method according to this patent Solar cell group made by connecting solar cells in series Solar cell manufacturing equipment according to this patent

Explanation of symbols

101: Substrate 102: Back electrode 103: Semiconductor layer 104: Transparent electrode 105: Light incident direction 106: Potential difference between the back electrode and the transparent electrode
111: Back electrode side extraction electrode 112: Insulator 113: Transparent electrode side extraction electrode
201: Transparent electrode 202: Resin 203: Semiconductor layer 204: Back electrode
211: Transparent substrate
221: Metal mask 222: Metal mask
301: Transparent electrode 302: Semiconductor layer 303: Back electrode 311: Transparent substrate
321: Laser
401: Substrate 402: First deposited film 403: Second deposited film
411: Board surface 412: Board back
501: Substrate 502: First deposited film 503: Second deposited film
601: Substrate 602: Back electrode 603: Semiconductor layer 604: Transparent electrode
611: Back electrode side extraction electrode 612: Transparent electrode side extraction electrode
621: Semiconductor layer thickness 622: Distance between back electrode and transparent electrode conductor
701: Substrate 702: Back electrode 703: N-type semiconductor layer 704: i, p-type semiconductor layer 705: Transparent electrode
711: Substrate surface 712: Substrate back surface
801a: Substrate 802a-c: Back electrode 803a: Semiconductor layer 804a-c: Transparent electrode
821: Fastener 822: Bolt
831: Conductor for lead-out electrode side 832: Lead-out lead for transparent electrode
841: One unit of solar cell (1) 842: One unit of solar cell (2) 843: One unit of solar cell (3)
901: Sputtering apparatus for forming back electrode 902: CVD apparatus for forming non-single crystal silicon thin film, n layer 903: CVD apparatus for forming non-single crystal silicon thin film, i layer 904: CVD apparatus for forming non-single crystal silicon thin film, For p layer 905: Sputtering device for transparent electrode formation
911: Auxiliary roller 912: Roller for changing cross-sectional shape 913: Auxiliary roller 914: Roller for changing cross-sectional shape 915: Roller for changing cross-sectional shape 916: Roller for changing cross-sectional shape 917: Auxiliary roller
921: Strip substrate carrying side end 922: Strip substrate carrying side end
931a, 932a, 933a, 934a, 935a: Position on substrate
931b, 932b, 933b, 934b, 935b: substrate cross section

Claims (6)

A method of manufacturing a semiconductor device in which a deposited film material is formed by flying a deposited film material onto a substrate, wherein an end of one surface of the substrate is folded into the one surface side or the back surface side of the one surface. The first step of concealing the end of the one surface from the direction in which the deposited film material is made to fly, and forming the first deposited film on one surface portion excluding the end of the one surface, and the end of the one surface The second step of forming the second deposited film over the end of the first surface and the one surface on one surface is exposed to the direction in which the deposited film material is made to fly back from the folding. A method for manufacturing a semiconductor element. 2. The method of manufacturing a semiconductor device according to claim 1, wherein the substrate is a strip-like flexible substrate. 3. The method of manufacturing a semiconductor device according to claim 2, wherein a roll-to-roll type substrate transport mechanism for pulling out the belt-like substrate wound in a roll shape from the roll and winding the drawn belt-like substrate in a roll shape. A method for manufacturing a semiconductor element, characterized by being used. An apparatus for manufacturing a semiconductor element, wherein a deposited film material is formed by flying a deposited film material on a substrate, and the edge of one surface of the substrate is folded into the one surface side or the back surface side of the one surface. The first step of concealing the end of the one surface from the direction in which the deposited film material is made to fly, and forming the first deposited film on one surface portion excluding the end of the one surface, and the end of the one surface The second step of forming the second deposited film over the end of the first surface and the one surface on one surface is exposed to the direction in which the deposited film material is made to fly back from the folding. A semiconductor device manufacturing apparatus having a mechanism for carrying out. 5. The semiconductor element manufacturing apparatus according to claim 4, wherein the substrate is a belt-like flexible substrate. 6. The apparatus for manufacturing a semiconductor device according to claim 5, wherein a roll-to-roll substrate transporting mechanism for pulling out the strip-shaped substrate wound in a roll shape from the roll and winding the pulled-out strip-shaped substrate in a roll shape. An apparatus for manufacturing a semiconductor element, comprising:

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