Solar cell and method for manufacturing solar cell

Abstract

Provided are: a solar cell capable of preventing short-circuiting during signaling connection; and a method for manufacturing the solar cell. In a solar cell 1 according to an aspect of the present invention, a first semiconductor layer 20 of a conductivity type different from that of a semiconductor substrate 10 has: a main function part 21 which has a first base end 23 formed at one side, in a first direction, of the semiconductor substrate 10 so as to extend over the entire length in a second direction and a plurality of collection portions 24 which each extend from the first base end 23 to the other side in the first direction and which have layered thereon a first electrode pattern 40; and a partition part 22 which is linearly formed at the other side end, in the first direction, of the semiconductor substrate 10 so as to extend over the entire length in the second direction, and which does not have layered thereon the first electrode pattern 40. A second semiconductor layer 30 of the same conductivity type as that of the semiconductor substrate 10 has a second base end 31 which is adjacent to one side, in the first direction, of the partition part 22 and which extends in the second direction, and a plurality of second collection portions 32 which each extend from the second base end 31 to the one side in the first direction.

Description

[Technical field]

[0001] The present invention relates to a solar cell and a method for manufacturing a solar cell. [Background technology]

[0002] A back-contact type solar cell is known in which a pair of semiconductor layers having different conductivity types are formed in complementary regions on the back side of a semiconductor substrate, and an electrode pattern is laminated on each semiconductor layer. In a back-contact type solar cell, in order to reduce the moving distance of carriers, it is preferable to alternately arrange strip-shaped semiconductor films having different polarities in a plan view and connect strip-shaped semiconductor films having the same polarity. Considering that a module is formed by connecting a plurality of solar cells, it is assumed that each strip-shaped semiconductor film is arranged to extend in the solar cell connection direction, a base end portion is provided on one side of the solar cell connection direction to connect an end of a strip-shaped semiconductor of one conductivity type, and a base end portion is provided on the other side of the solar cell connection direction to connect an end of a strip-shaped semiconductor of the other conductivity type, that is, a pair of semiconductor layers are formed in a comb shape and arranged so that their teeth mesh with each other (see, for example, Patent Document 1).

[0003] Patent Document 1 discloses a manufacturing method for obtaining two solar cells by forming the cell structures (semiconductor layers and electrodes) of a pair of solar cells on a semiconductor wafer in a mirror image (line symmetry) such that the connection parts of one of the semiconductor layers are adjacent to each other, and then cutting the semiconductor wafer at the boundary of the cell structures. In Patent Document 1, an octagonal semiconductor wafer having chamfered corners is cut in the center to form two solar cells, and as a result, each solar cell has an asymmetric shape in which the corner on the side where the base end part of one of the semiconductor layers is formed is chamfered.

[0004] When forming a solar cell module using a plurality of solar cells, it is common to arrange a plurality of solar cell strings, each of which is formed by arranging a plurality of solar cells in a row. In the solar cell module described in Patent Document 1, the shape of the solar cell is asymmetric, so that the orientation of the solar cell in the solar cell string can be easily confirmed. Since the orientation of the solar cell string is determined depending on the electrical connection, the orientation of the solar cell in the solar cell module of Patent Document 1 is reversed for each row. Therefore, if a plurality of solar cells are formed on a semiconductor wafer with the same orientation, solar cells with reversed polarity of the semiconductor layer can be obtained, so that the chamfered portions in the solar cell module can be unified on the same side. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-163988 A Summary of the Invention [Problem to be solved by the invention]

[0006] In Patent Document 1, a gap is formed between the solar cells, but a so-called shingled structure in which the ends of the solar cells are stacked in a certain direction may be adopted as a configuration for improving the output per area of ​​the module. In this case, the electrode structure at the end of the solar cell on the front side abuts against the semiconductor substrate (light receiving surface) of the solar cell on the back side. If the polarity of the abutting portion of the electrode structure of the solar cell on the front side is equal to the polarity of the semiconductor substrate on the back side, the solar cell may be short-circuited. As described above, when multiple solar cells are formed on a semiconductor wafer with the same orientation, a minute semiconductor layer having an unintended polarity may be formed at the end of the solar cell due to an error in the cutting position. For this reason, when multiple solar cells are formed on a semiconductor wafer with the same orientation, there is a risk of a short circuit occurring during shingled connection. In view of such circumstances, the present invention aims to provide a solar cell and a manufacturing method thereof that can prevent a short circuit during shingled connection. [Means for solving the problem]

[0007] a first semiconductor layer formed on a rear surface of the semiconductor substrate and having a different conductivity type than the semiconductor substrate, and a second semiconductor layer formed on the rear surface of the semiconductor substrate and having the same conductivity type as the semiconductor substrate; a first electrode pattern stacked on the first semiconductor layer and a second electrode pattern stacked on the second semiconductor layer, the first semiconductor layer having a first base end formed at an end on one side of the first direction of the semiconductor substrate over an entire length in a second direction intersecting the first direction, and a plurality of first collecting portions extending from the first base end to the other side of the first direction, the first electrode pattern being stacked on a main functional portion and an isolation portion formed linearly at an end on the other side of the first direction of the semiconductor substrate over an entire length in the second direction, and on which the first electrode pattern is not stacked; and the second semiconductor layer having a second base end adjacent to the one side of the isolation portion in the first direction and extending in the second direction, and a plurality of second collecting portions extending from the second base end to the one side of the first direction.

[0008] In the solar cell, the average width in the first direction of the isolation portion may be smaller than the average width in the second direction of the first collecting portion, and the average width in the second direction of the first collecting portion may be smaller than the average width in the first direction of the first base end portion.

[0009] In the solar cell, the isolation portion may have an average width in the first direction of 2000 μm or less.

[0010] A solar cell manufacturing method according to one aspect of the present invention includes the steps of: forming, on a rear surface of a semiconductor wafer having a first conductivity type, a plurality of cell structures each having a first semiconductor layer having a conductivity type different from that of the semiconductor wafer, a second semiconductor layer having the same conductivity type as that of the semiconductor wafer, a first electrode pattern laminated on the first semiconductor layer, and a second electrode pattern laminated on the second semiconductor layer; and cutting the semiconductor wafer at boundaries of the cell structures, the plurality of cell structures being formed side by side in a first direction and oriented in the same direction, and the first semiconductor layer being arranged at an end of the cell structure on one side in the first direction such that the first semiconductor layer intersects with the first direction. the first electrode pattern is laminated; and an isolation portion is formed linearly at an end of the cell structure on the other side of the first direction over the entire length in the second direction, and the first electrode pattern is not laminated. In a step of forming the cell structure, the main functional portion and the isolation portion of the cell structure adjacent to one side in the first direction are formed continuously, and in a step of cutting the semiconductor wafer, the main functional portion and the isolation portion of the cell structure adjacent to one side in the first direction are separated. Effect of the Invention

[0011] According to the present invention, it is possible to provide a solar cell that can prevent short circuits during shingling connection. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a rear view of a solar cell according to one embodiment of the present invention. [Diagram 2] 2 is a cross-sectional view taken along line AA of the solar cell of FIG. 1. [Diagram 3] 2 is a flowchart showing the steps of a method for manufacturing the solar cell of FIG. [Figure 4] 4 is a cross-sectional view of the semiconductor wafer after the cell structure forming step in FIG. 3. [Diagram 5] 2 is a cross-sectional view of a solar cell module having the solar cell of FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, each embodiment of the present invention will be described with reference to the attached drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals. For simplification, illustrations and reference numerals of members may be omitted, in which case, other drawings shall be referred to. For convenience, the shapes and dimensions of various members in the drawings have been adjusted to make them easy to see.

[0014] <Solar cell> Fig. 1 is a back view showing a solar cell 1 according to one embodiment of the present invention. Fig. 2 is a cross-sectional view of the solar cell 1. The solar cell 1 includes a semiconductor substrate 10 having a first conductivity type, a first semiconductor layer 20 having a different conductivity type from that of the semiconductor substrate 10 and a second semiconductor layer 30 having the same conductivity type as that of the semiconductor substrate 10, which are formed on the back surface (the surface opposite to the light-receiving surface) of the semiconductor substrate 10, a first electrode pattern 40 laminated on the first semiconductor layer 20, and a second electrode pattern 50 laminated on the second semiconductor layer 30.

[0015] The semiconductor substrate 10 can be formed of a crystalline silicon material such as single crystal silicon or polycrystalline silicon. It may also be formed of other semiconductor materials such as gallium arsenide (GaAs). The semiconductor substrate 10 is, for example, an n-type semiconductor substrate in which a crystalline silicon material is doped with an n-type dopant. An example of the n-type dopant is phosphorus (P). The semiconductor substrate 10 functions as a photoelectric conversion substrate that absorbs incident light from the light-receiving surface side and generates photocarriers (electrons and holes). By using crystalline silicon as the material of the semiconductor substrate 10, a relatively high output (stable output regardless of illuminance) can be obtained even when the dark current is relatively small and the intensity of the incident light is low.

[0016] The first semiconductor layer 20 and the second semiconductor layer 30 attract carriers of different polarities from inside the semiconductor substrate 10, and collect charges of different polarities. Specifically, when the semiconductor substrate 10 is an n-type, the first semiconductor layer 20 is formed of a p-type semiconductor, and the second semiconductor layer 30 is formed of an n-type semiconductor. The first semiconductor layer 20 and the second semiconductor layer 30 can be formed of, for example, an amorphous silicon material containing a dopant that imparts a desired conductivity type. An example of the p-type dopant is boron (B), and an example of the n-type dopant is the above-mentioned phosphorus (P).

[0017] The first semiconductor layer 20 and the second semiconductor layer 30 are formed in a substantially complementary shape on the back surface of the semiconductor substrate 10. In other words, substantially the entire area of ​​the back surface of the semiconductor substrate 10 is covered with either the first semiconductor layer 20 or the second semiconductor layer 30.

[0018] The first semiconductor layer 20 has a main functional section 21 on which the first electrode pattern 40 is laminated, and an isolation section 22 that is isolated from the main functional section 21 and on which the first electrode pattern 40 is not laminated. The main functional section 21 has a first base end 23 formed at an end on one side in the first direction of the semiconductor substrate 10 over substantially the entire length in a second direction intersecting with the first direction, and a plurality of first collection sections 24 extending from the first base end 23 to the other side in the first direction. The isolation section 22 is formed linearly over the entire length in the second direction at an end on the other side in the first direction of the semiconductor substrate 10.

[0019] The second semiconductor layer 30 has a second base end 31 adjacent to one side of the isolation portion 22 in the first direction and extending in the second direction, and a plurality of second collection portions 32 extending from the second base end 31 to one side in the first direction.

[0020] In order to reduce the moving distance of carriers in the semiconductor substrate 10 and improve the photoelectric conversion efficiency, the first collecting portion 24 and the second collecting portion 32 are preferably alternately formed with a relatively small constant width that allows the first electrode pattern 40 or the second electrode pattern 50 described later to be stacked. The first base end 23 and the second base end 31 preferably have a width larger than the first collecting portion 24 and the second collecting portion 32 in order to reduce the electrical resistance because the charges extracted by the first collecting portion 24 and the second collecting portion 32 flow into them. Since the isolating portion 22 does not contribute to photoelectric conversion, it is preferable that the average width of the isolating portion 22 in the second direction is set to the minimum width that can be continuously formed in the first direction. For this reason, it is preferable that the average width of the isolating portion 22 in the first direction is smaller than the average width of the first collecting portion 24 in the second direction, and the average width of the first collecting portion 24 in the second direction is smaller than the average width of the first base end 23 in the first direction. Specifically, the lower limit of the average width of the isolating portion in the first direction is preferably 100 μm, and more preferably 200 μm. On the other hand, the upper limit of the average width in the first direction of the isolating parts is preferably 2000 μm, and more preferably 1000 μm.

[0021] The first electrode pattern 40 and the second electrode pattern 50 are formed of a material having high conductivity, such as a metal. The first electrode pattern 40 and the second electrode pattern 50 may be a laminate of a transparent electrode layer made of, for example, ITO (Indium Tin Oxide), zinc oxide (ZnO), or the like, which is laminated on the first semiconductor layer 20 and the second semiconductor layer 30, and a metal electrode layer mainly made of a metal.

[0022] The first electrode pattern 40 is provided to extract charges from the first semiconductor layer 20, and the second electrode pattern 50 is provided to extract charges from the second semiconductor layer 30. The first electrode pattern 40 and the second electrode pattern 50 are laminated so as to leave margins at the outer edges of the first semiconductor layer 20 (main functional section 21) and the second semiconductor layer 30 to prevent short circuits.

[0023] Specifically, the first electrode pattern 40 has a first busbar electrode 41 stacked on the first base end 23 and extending in the second direction, and a plurality of first finger electrodes 42 extending from the first busbar electrode 41 to the other side in the first direction and stacked on each of the first collecting portions 24. The second electrode pattern 50 has a second busbar electrode 51 stacked on the second base end 31 and extending in the second direction, and a plurality of second finger electrodes 52 extending from the second busbar electrode 51 to one side in the first direction and stacked on each of the second collecting portions 32.

[0024] As described above, the solar cell 1 has the first semiconductor layer 20 (the first base end 23 and the isolating portion 22) having a different conductivity type from the semiconductor substrate 10 at both ends in the first direction over the entire length in the first direction. Therefore, when a plurality of solar cells 1 are connected in a shingled manner in the first direction, the semiconductor substrate 10 may come into contact with the first semiconductor layer 20 of the adjacent solar cell 1, but will not come into contact with the second semiconductor layer 30. Therefore, the solar cell 1 will not be short-circuited during shingled connection. Note that in the figure, the semiconductor substrate 10 of the solar cell 1 on the back side and the first semiconductor layer 20 and the second semiconductor layer 30 of the solar cell 1 on the front side do not seem to come into contact with each other due to the thicknesses of the first electrode pattern 40 and the second electrode pattern 50, but the actual thicknesses of the first electrode pattern 40 and the second electrode pattern 50 are small, so that the semiconductor substrate 10 of the solar cell 1 on the back side can easily come into contact with the isolating portion 22 due to slight inclination or deformation.

[0025] <Solar cell manufacturing method> The solar cell 1 can be manufactured by a solar cell manufacturing method according to one embodiment of the present invention, shown in FIG.

[0026] The solar cell manufacturing method of this embodiment includes a step of forming a plurality of cell structures C on the back surface of a semiconductor wafer W (step S1: cell structure forming step) and a step of cutting the semiconductor wafer W at the boundaries of the cell structures C (step S2: cutting step). The semiconductor wafer W is a large, plate-shaped semiconductor that can be cut into a plurality of semiconductor substrates 10 by cutting. The cell structure C is a concept that collectively includes the components of each solar cell other than the semiconductor substrate 10, that is, the first semiconductor layer 20, the second semiconductor layer 30, the first electrode pattern 40, and the second electrode pattern 50.

[0027] In the cell structure forming process of step S1, as shown in Fig. 4, a plurality of cell structures C are formed on a semiconductor wafer W in a line in the first direction and oriented in the same direction. Note that Fig. 4 shows a cross section at the same position as Fig. 2, that is, a cross section along line AA in Fig. 1. As is clear from the description of the solar cell 1, the first semiconductor layer 20 has a first base end 23 formed at an end on one side of the first direction of each cell structure C over the entire length in the second direction intersecting with the first direction, and a plurality of first collecting portions 24 extending from the first base end 23 to the other side of the first direction, and has a main function portion 21 on which the first electrode pattern 40 is laminated, and an isolation portion 22 formed linearly over the entire length in the second direction at an end on the other side of the first direction of each cell structure, and on which the first electrode pattern 40 is not laminated.

[0028] In the cell structure forming process, the main functional unit 21 of the cell structure C on the other side in the first direction and the isolation unit 22 of the adjacent cell structure C on one side in the first direction are formed continuously. That is, by forming the first semiconductor layer 20 to extend across the boundary (shown by the dashed line) of the cell structure C, the main functional unit 21 of the cell structure C on the other side in the first direction and the isolation unit 22 of the cell structure C on one side in the first direction are formed integrally. That is, in Fig. 4, the first semiconductor layer 20 of the cell structure C on the right side extends slightly beyond the boundary of the cell structure C to the cell structure C on the left side, and the portion exceeding the boundary of this cell structure C constitutes the isolation unit 22 of the cell structure C on the left side.

[0029] The first semiconductor layer 20 and the second semiconductor layer 30 can be formed by forming a resist pattern and selectively stacking semiconductor materials by a film formation technique such as CVD. The first electrode pattern 40 and the second electrode pattern 50 can be formed by a method such as etching a metal layer formed by plating using a seed layer formed by sputtering or the like as an adherend, or by printing and baking a conductive paste.

[0030] In the cutting process of step S2, the semiconductor wafer W is cut along the boundary of the cell structure C to separate the main functional portion 21 of the cell structure C on the other side of the first direction from the isolation portion 22 of the adjacent cell structure C on one side of the first direction, thereby cutting out the solar cell 1.

[0031] The semiconductor wafer W can be cut by forming scribed grooves by, for example, laser irradiation, milling, or the like, and then bending the semiconductor wafer W to break it.

[0032] <Solar cell module> 5 is a cross-sectional view of a solar cell module M having a plurality of solar cells 1. The solar cell module M includes a plurality of solar cell strings 100 each formed by arranging and connecting a plurality of solar cell cells 1 in a row, a plate-shaped front surface protective material 200 covering the front sides of the plurality of solar cell strings 100, a plate-shaped or sheet-shaped back surface protective material 300 covering the back sides of the plurality of solar cell strings 100, and a sealing material 400 filled between the front surface protective material 200 and the back surface protective material 300.

[0033] The solar cell string 100 has a plurality of solar cells 1 arranged in a row in a first direction, and an interconnector 2 that connects adjacent solar cells. In the solar cell string 100, an end portion on one side in the first direction of each solar cell 1 is arranged overlapping the back side of an end portion on the other side in the first direction of an adjacent solar cell 1. The interconnector 2 is formed from a conductor such as metal foil or metal mesh wire, and connects a first bus bar electrode 41 of the solar cell 1 overlapping on the front side to a second bus bar electrode 51 of the solar cell 1 overlapping on the back side.

[0034] In the solar cell string, as shown in the figure, the interconnector 2 may abut against the isolation portion 22 of the first semiconductor layer 20, but since the isolation portion 22 is isolated from the main functional portion 21 that contributes to photoelectric conversion, no inconvenience occurs even if the interconnector 2 comes into contact.

[0035] The surface protection material 200 protects the solar cell string 100 by covering the surface of the solar cell string 100 via the sealing material 400. The surface protection material 200 is preferably formed of a transparent and scratch-resistant material such as glass, polycarbonate, acrylic resin, etc., and has excellent weather resistance. Specifically, examples of the material of the surface protection material 200 include transparent resins such as acrylic resins and polycarbonate resins, and glass. In addition, the surface of the surface protection material 200 may be processed to have an uneven shape or coated with an anti-reflection coating layer in order to suppress light reflection. The surface protection material 200 may have a light-shielding region on the outer periphery.

[0036] The surface protective material 200 preferably has a sufficient thickness to provide the strength to maintain the shape of the solar cell module M. Furthermore, by using the surface protective material 200 that has been formed into a desired shape in advance, a solar cell module M having the desired shape can be obtained.

[0037] The solar cell string 100 may be formed to have a length substantially equal to the length in the first direction of the light-transmitting region inside the light-shielding region of the surface protective material 200. This increases the effective area for receiving light by the solar cell string 100, while preventing a decrease in photoelectric conversion efficiency caused by a lack of light entering some of the solar cells 1 at the end of the solar cell string 100. Note that the multiple solar cell strings 100 may be connected to each other by wiring material (not shown).

[0038] The back surface protective material 300 is a layer that protects the back surface side of the solar cell string 100. The material of the back surface protective material 300 is not particularly limited, but is preferably a material that prevents the intrusion of water or the like (high water impermeability). Specifically, the back surface protective material 300 can be formed from, for example, glass, polyethylene terephthalate (PET), acrylic resin, polyethylene (PE), olefin resin, fluorine-containing resin, silicone-containing resin, or other resin. The back surface protective material 300 may also be a laminate of a resin layer and a metal layer such as aluminum foil. In addition, the color (light reflection characteristics) of the back surface protective material 300 when viewed from the front side surface is preferably similar to the color of the front side surface of the solar cell 1 in order to make the gaps between the solar cell strings 100 less noticeable and improve the aesthetic appearance of the solar cell module M.

[0039] The sealing material 400 seals the solar cell string 100 in the space between the front surface protective material 200 and the back surface protective material 300, and suppresses deterioration of the solar cell string 100 due to moisture or the like. The sealing material 400 is formed from a material that has transparency and has adhesion to the front surface protective material 200 and the solar cell string 100. The material forming the sealing material 400 preferably has thermoplasticity so that the gap between the front surface protective material 200 and the solar cell string 100 can be sealed by heat pressing. Specifically, the material forming the sealing material 400 may be, for example, a resin composition mainly composed of ethylene / vinyl acetate copolymer (EVA), ethylene / α-olefin copolymer, ethylene / vinyl acetate / triallyl isocyanurate (EVAT), polyvinyl butyrate (PVB), acrylic resin, urethane resin, silicone resin, or the like.

[0040] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and variations are possible. Furthermore, the solar cell according to the present invention may have components other than those described in the above-described embodiments. For example, the solar cell according to the present invention may have an intrinsic semiconductor layer that separates the first semiconductor layer and the second semiconductor layer. Furthermore, the planar shapes of the main functional portion of the first semiconductor layer and the second semiconductor layer, and thus the planar shapes of the first electrode pattern and the second electrode pattern, may be appropriately modified. [Explanation of symbols]

[0041] 1 Solar cell 2 Interconnector 10. Semiconductor Substrate 20 First semiconductor layer 21 Main function section 22 Isolation section 23 First proximal end 24 First Collection Section 30 Second semiconductor layer 31 Second proximal end 32 2nd Collection Section 40 First electrode pattern 41 First bus bar electrode 42 First finger electrode 50 Second electrode pattern 51 Second bus bar electrode 52 Second Finger Electrode 100 solar cell strings 200 Surface protection material 300 Back protection material 400 Encapsulating material C Cell Structure M Solar Cell Module W Semiconductor wafer

Claims

1. a semiconductor substrate having a first conductivity type; a first semiconductor layer formed on a rear surface of the semiconductor substrate and having a conductivity type different from that of the semiconductor substrate, and a second semiconductor layer having the same conductivity type as that of the semiconductor substrate; a first electrode pattern laminated on the first semiconductor layer and a second electrode pattern laminated on the second semiconductor layer; Equipped with The first semiconductor layer is a main functional section including a first base end portion formed at an end portion on one side in a first direction of the semiconductor substrate over an entire length in a second direction intersecting the first direction, and a plurality of first collecting portions extending from the first base end portion to the other side in the first direction, and on which the first electrode pattern is laminated; an isolation portion that is linearly formed at an end portion of the semiconductor substrate on the other side in the first direction over the entire length in the second direction, and on which the first electrode pattern is not stacked; having The second semiconductor layer has a second base end portion adjacent to one side of the isolation portion in the first direction and extending in the second direction, and a plurality of second collecting portions extending from the second base end portions to one side in the first direction.

2. 2. The solar cell of claim 1, wherein an average width in the first direction of the isolation portion is smaller than an average width in the second direction of the first collecting portion, and an average width in the second direction of the first collecting portion is smaller than an average width in the first direction of the first base end portion.

3. The solar cell according to claim 1 , wherein the average width of the isolation portion in the first direction is 2000 μm or less.

4. A step of forming a plurality of cell structures on a back surface of a semiconductor wafer having a first conductivity type, the cell structures each having a first semiconductor layer having a conductivity type different from that of the semiconductor wafer, a second semiconductor layer having the same conductivity type as that of the semiconductor wafer, a first electrode pattern laminated on the first semiconductor layer, and a second electrode pattern laminated on the second semiconductor layer; cutting the semiconductor wafer at boundaries of the cell structure; Equipped with The plurality of cell structures are aligned in a first direction and oriented in the same direction, The first semiconductor layer is a main functional section including a first base end portion formed at an end portion on one side in the first direction of the cell structure over an entire length in a second direction intersecting the first direction, and a plurality of second collecting portions extending from the first base end portion to the other side in the first direction, and on which the first electrode pattern is laminated; an isolating portion that is linearly formed at an end portion on the other side in the first direction of the cell structure over an entire length in the second direction, and on which the first electrode pattern is not laminated; having In the step of forming the cell structure, the main functional portion and the isolation portion of the cell structure adjacent to the one side in the first direction are formed continuously, the main functional portion and the isolation portion of the cell structure adjacent to one side in the first direction are separated in the step of cutting the semiconductor wafer.

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