JP2000294819A - Manufacture of solar battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress increase of the area of a surface electrode keeping a series resistance low, by forming a main electrode by electrolytic plating so as to be at the peripheral brim part of a semiconductor substrate. SOLUTION: A silicon substrate 1 is thermally oxidized and a silicon oxide film 2 is formed, and an N-type diffusion layer 3 is formed. Seed metals 5, 6 formed on the silicon substrate 1 are used as cathodes. A flat board anode 8 is arranged in parallel to the seed metal 6, and an anode 9 is arranged in parallel to the seed metal 5. These are immersed in a plating solution 11, and voltage is applied. The seed metals 5, 6 on both sides of the silicon substrate 1 are plated with Ag, simultaneously. Following this, a reflection preventing film is formed on the substrate surface by an oxide film composed of two layers of TiO2 and Al2O3. Heat treatment is performed to increase the degree of adhesion between the surface and backside electrodes with the silicon substrate 1. Finally, the silicon substrate 1 is diced to final solar battery dimensions. Accordingly, it becomes possible to manufacture a solar battery provided with a main electrode having a thicker film thickness and a narrower area, and especially a lower series resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a solar cell, and more particularly, to a method for manufacturing a solar cell in which electrodes in the solar cell are formed by electrolytic plating, in particular, the series resistance is reduced.

[0002]

2. Description of the Related Art A conventionally proposed solar cell is manufactured, for example, as follows.

(1) In a thinning etching step, the thickness of the silicon substrate (P-type) 1 initially charged is chemically etched to the thickness of the final solar cell (FIG. 4A). (2) In a first oxidation step, an oxide film 2 is formed on both surfaces of the silicon substrate 1 (FIG. 4B). (3) After protecting the back surface of the silicon substrate 1 with respect to the light receiving surface with a masking agent such as a resist and an acid-resistant tape, the silicon substrate 1 is immersed in an HF solution to dissolve only the oxide film 2 on the light receiving surface (FIG. c)). (4) The N-type diffusion layer 3 is formed only on the light receiving surface by diffusing phosphorus into the silicon substrate 1 (FIG. 4D). (5) Then, the oxide film 2 on the back surface side is removed (FIG. 4).
(E))

(6) The purpose is to form an electrode of a predetermined shape to be connected to the N-type diffusion layer 3 of the silicon substrate 1 by electrolytic plating in a later step, and to form a predetermined electrode on the surface of the silicon substrate 1 by photolithography. A resist pattern 4 having a shape is formed (FIG. 5F). (7) For the purpose of producing a surface electrode on the seed metal by electrolytic plating in a later step, a seed metal 5 to be a base of the plated electrode is formed by an evaporation method, and the resist pattern 4 is peeled off in a lift-off step ( FIG.
(G)). (8) In order to form a back electrode on the seed metal by electrolytic plating in a later step, a seed metal 6 serving as a base of the plated electrode is formed by vapor deposition (FIG. 5).
(H)). (9) Electroplating is performed on the front side seed metal 5 and the rear side seed metal 6 by electrolytic plating to complete the front surface electrode 51 and the back surface electrode 61 (FIG. 5 (i)). (10) An antireflection film 7 for reducing light reflection is formed on the surface of the obtained silicon substrate 1 by a vapor deposition method (FIG. 5).
(J)). (11) Heat treatment is performed to increase the adhesion between the front surface electrode 51 and the back surface electrode 61 and the silicon substrate 1 (sintering step). (12) Dicing to final solar cell dimensions.

Here, the surface electrode 5 formed on the light receiving surface side
1 includes a plurality of sub-electrodes 53 for collecting a photocurrent generated in the solar cell element, and a plurality of sub-electrodes 53, as shown in FIG.
Main electrode 52 whose main purpose is to electrically connect
And a comb-shaped electrode composed of a connector for extracting a current generated in the solar cell element to the outside of the solar cell element, and an electrode pad 54 provided for electrically connecting the solar cell element. It is.

The surface electrode 51 shown in FIG. 6 has a shape corresponding to one completed solar cell element.
Normally, as shown in FIG. 7, a pattern of a plurality of surface electrodes 51 is formed on one silicon substrate 1.

In the electrolytic plating of step (9), as shown in FIG. 8, an anode made of a metal to be plated is usually placed in a plating tank 12 filled with a plating solution 11 containing metal ions to be plated. 8, 9 and seed metals 5, 6 formed on both surfaces of the silicon substrate 1 to be plated.
And a voltage is applied to both electrodes to perform plating on both surfaces of the silicon substrate 1. On this occasion,
The anodes 8 and 9 are made of a metal plate having the same area as the silicon substrate 1 on which the seed metals 5 and 6 as the cathodes are formed, and are arranged so as to be parallel to the cathodes.
However, when plating is performed using such anodes 8 and 9, the plating metal grows thicker in the peripheral portion of the silicon substrate 1 than in the central portion. This is because charges concentrate on the periphery when a voltage is applied. Therefore, in order to perform plating on the silicon substrate 1 with a uniform film thickness, a method is used in which the peripheral portion of the anode corresponding to the peripheral portion of the silicon substrate 1 which is particularly thick is removed, and an anode smaller than the cathode is used. is there. Thereby, it is possible to prevent the charge from being concentrated on the peripheral portion of the silicon substrate 1. Further, as shown in FIG. 9, there is a method of providing a barrier 10 between the peripheral portion of the silicon substrate 1 and the anodes 8 and 9 so as to prevent concentration of electric charges.

By the way, the most effective method for improving the conversion efficiency of a solar cell is to improve the light collection efficiency. Various methods can be considered to improve the light collection efficiency.As a relatively simple method, the electrode area on the surface of the solar cell element is reduced, and the loss of incident light due to reflection from the electrode is minimized. Is incident on the solar cell element. However, reducing the electrode area causes an increase in the series resistance of the solar cell element, and has a limit. Among the series resistance of the solar cell, the series resistance due to the surface electrode is inversely proportional to the cross-sectional area of the electrode in the current direction and increases in proportion to the length of the electrode when the electrode material is the same. Therefore, in order to reduce the series resistance, it is effective to increase the electrode thickness or increase the electrode width to increase the sectional area in the current direction. However, when the electrode width is increased, the loss of incident light increases, and it is rather desired to increase the electrode thickness. Further, this series resistance needs to be reduced particularly at the main electrode through which a large amount of current flows.

In general, in the electrolytic plating as described above, since the seed metal pattern is grown by plating in both the film thickness direction and the width direction, it is necessary to increase the thickness only of the film thickness without increasing the electrode width. It is difficult. Further, when comparing the main electrode and the sub-electrode, the total area of the plating electrode growing in the width direction is several tens to several times larger than the main electrode because the number of the sub-electrodes is larger. One hundred times larger. As a result, in the conventional method as described above, the main electrode cannot be plated thick in order to prevent the sub-electrode from being thickly plated. Therefore, it is necessary to increase the electrode area and reduce the series resistance, and the incident light However, there was a problem that the loss was increased. The present invention has been made to solve the above problems, and has as its object to provide a method for manufacturing a solar cell in which an increase in the electrode area of the surface electrode is suppressed while the series resistance is kept small.

[0010]

According to the present invention, a semiconductor substrate, a sub-electrode formed on the surface of the semiconductor substrate and collecting current generated by a solar cell element, and electrically connected to the sub-electrode. When manufacturing a solar cell including a front electrode and a back electrode composed of a main electrode, a method for manufacturing a solar cell is provided, in which the main electrode is formed by electrolytic plating so as to be arranged on a peripheral portion of a semiconductor substrate.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a method for manufacturing a solar cell mainly including a semiconductor substrate, a front electrode composed of a main electrode and a sub-electrode, and a back electrode, wherein at least the main electrode constituting the front electrode is electrolytically plated. Is a method for manufacturing a solar cell formed by the method described above.

The semiconductor substrate for manufacturing a solar cell which can be used in the present invention means a substrate for simultaneously forming one or a plurality of solar cell elements, and includes a wafer and the like. As this substrate, for example, a known substrate such as a semiconductor such as silicon or germanium, or a compound semiconductor such as GaP or GaAs can be used. Among them, a silicon substrate is preferable.

The semiconductor substrate may contain any of N-type impurities such as phosphorus and P-type impurities such as boron. Preferably, an impurity diffusion layer having a desired impurity concentration is formed on the front and back surfaces of the semiconductor substrate. It is preferable that such an impurity diffusion layer has an impurity concentration that is generally used for a semiconductor element, a solar cell, or the like. For example, the impurity concentration of the N-type and / or P-type impurity diffusion layers is 1.0 × 10 ^{19 to} 1.0
About × 10 ²⁰ cm ^-3 . If the thickness of the semiconductor substrate is about the thickness used for ordinary solar cells,
There is no particular limitation, for example, 200 to 400
One having a size of about μm is exemplified. Note that the surface of the semiconductor substrate may have a texture shape that reduces reflection of incident light. On the other hand, the back surface may have a BSF (Back Surface Field) structure in which a high concentration impurity diffusion layer is formed.

Using the above-mentioned semiconductor substrate, a front electrode and a back electrode are formed by electrolytic plating. According to this method, after a seed metal is formed on the front and back surfaces of the semiconductor substrate in advance, electrolytic plating is performed on the seed metal to form a front surface electrode and a back surface electrode.

The seed metal can be formed on both the front surface and the back surface by a known film forming method such as a vacuum evaporation method, a BE evaporation method, and a sputtering method. In addition, as a method of patterning the seed metal into a desired shape, a known method, for example, a lift-off method, photolithography, an etching technique, or the like can be used. As the material of the seed metal, a single layer film of a metal such as aluminum, gold, silver, copper, nickel, lead, titanium, tantalum, palladium, or Al / Ti / Pd, Al / Ti / Pd / A
g, Ti / Pd, Ti / Pd / Ag, Ti / Ag, Au
/ Zn / Ag and the like.
In particular, the seed metal of the back electrode is preferably a laminated film of Al / Ti / Pd or Al / Ti / Pd / Ag having high reflectivity. The thickness of these seed metals is not particularly limited.
About 10,000 °. Since the seed metal is a starting point for growing the electrode by electroplating in a later step, the seed metal is preferably formed in a shape substantially corresponding to the front surface electrode and the back surface electrode. For example,
The seed metal for forming the surface electrode should be formed in a comb shape, a lattice shape, or the like, with an area of about 1 to 10% of the light receiving surface, in order to increase the incident light amount of the finally obtained solar cell. Can be. In addition, the seed metal for forming the back electrode can form a back electrode that can be incident on the light receiving surface and that is incident on the back surface without being absorbed by the substrate and reflected by the back surface and absorbed in the substrate. In addition, it is preferable to form an area of about 80% or more with respect to the back surface on almost the entire surface except the periphery of the element.

As a method of forming a front surface electrode and a back surface electrode by performing electroplating on the seed metal, generally used electroplating can be performed by selecting desired conditions. Thus, a desired front surface electrode and back surface electrode can be formed. In the electroplating, for example, in a plating solution containing metal ions to be plated, an anode made of a metal to be plated and a cathode made of a seed metal formed on both surfaces of a semiconductor substrate to be plated are immersed in both electrodes. This can be performed by applying a voltage.

Here, examples of the metal to be electroplated on the seed metal include gold, silver, copper, nickel, palladium, platinum and the like.

As the plating solution, as described above, gold,
When plating silver, copper, nickel, palladium, platinum or the like on the seed metal, a cyanide containing these metal ions (for example, a cyan neutral type, a cyan weak acid type, a cyan acid type, a cyan acid type) Non-cyan-based (eg, non-cyan-based neutral type, non-cyan-based slightly acidic type, non-cyan-based acidic type, non-cyan-based weak alkali type, non-cyan-based alkali type, etc.) plating solutions. No. In the plating solution, if desired, smoothing and glossing of the finally obtained front and rear electrodes,
In order to improve crystal refinement, adhesion, reduction of residual stress, etc., an additive or the like may be appropriately added.

As the anode, as described above, gold, silver,
When copper, nickel, palladium, platinum, or the like is plated on the seed metal, it is preferable that the metal is formed of the same high-purity metal plate as these materials. The size of the anode is preferably, for example, approximately the same as or larger than the projected area of the cathode facing the cathode. Also,
The shape of the anode may be a flat plate shape, or, in the outer peripheral portion, in other words, a portion corresponding to the main electrode (described later) of the surface electrode finally formed by electrolytic plating, may have a convex shape in the semiconductor substrate direction. It may have a part. The anode is
It is preferable to have a convex portion because the distance from the cathode is reduced, and the main electrode can be formed in a thicker film by accelerating charge concentration. The thickness of the anode is not particularly limited in the case of a flat plate shape,
For example, when there is a convex portion of about 5 mm or more, the thickness of the concave portion is not particularly limited.
The thickness of the convex portion is about 1 to 5 cm in addition to the concave portion.

When performing electrolytic plating, the anode and a semiconductor substrate having a seed metal formed on the front and back surfaces thereof are separated from each other by:
Arrange them so that they are almost parallel. The distance between the seed metal and the anode at this time can be appropriately adjusted depending on the current density at the time of electrolytic plating, the type and concentration of the plating solution, and the like. For the formation of the surface electrode, for example, 3 to 15 cm
(If the outer peripheral portion of the anode has a convex portion, the distance between the seed metal and the convex portion is approximately 3 to 15 cm), and to form the back surface electrode, the distance is approximately 1 to 15 cm. It can be. Further, the plating solution is adjusted to 20-70.
° C, and 0.1-3.0 between anode and cathode.
Applying a voltage so as to have a current density of about A / dm ² is mentioned.

By the above-described electrolytic plating, a front electrode and a back electrode can be simultaneously formed on the front and back surfaces of the semiconductor substrate, respectively. In the present invention, the front surface electrode and the back surface electrode may be simultaneously formed of the same material, or the back surface electrode may be separately formed before or after forming the front surface electrode by electrolytic plating. It may be formed.

The shape of the surface electrode formed by electrolytic plating is not particularly limited, but is mainly composed of a sub-electrode for collecting a photocurrent generated in the solar cell element and a main electrode electrically connected to the sub-electrode. . Here, as the sub-electrode, a plurality of sub-electrodes having the same shape such as a comb tooth shape may be formed substantially in parallel, or a plurality of rectangular shapes such as a lattice shape may be arranged vertically and horizontally. May be formed by arranging a plurality of different shapes each having a different shape in a vertical and horizontal diagonal manner. Further, a spiral shape or a bent shape may be formed over the light receiving surface.
Only one may be formed. Further, the main electrode needs to be electrically connected to all of the sub-electrodes when a plurality of sub-electrodes are formed, and to the sub-electrode when only one sub-electrode is formed. The shape of the main electrode is not particularly limited as long as it is connected to the sub-electrode.
It is preferable that the shape is such that it is arranged on the peripheral portion of the finally obtained solar cell element. Further, the main electrode may have a pad portion for connecting to a connector when extracting the current collected by the sub-electrode to the outside. The thicknesses of the sub-electrode and the main electrode of the surface electrode finally obtained are about 5 to 15 μm and about 6 to 17 μm, respectively.

As shown in FIG. 1, for example, a pattern constituting one solar cell element is a surface electrode.
Two may be arranged on one semiconductor substrate, one may be arranged, or three or more may be arranged. In this case, it is preferable that the main electrode constituting the surface electrode is formed so as to be disposed on the peripheral edge of the semiconductor substrate. Further, as shown in FIG. 3, the edge of the peripheral portion of the semiconductor substrate on which the main electrode constituting the surface electrode is disposed may have a substantially linear shape. After forming the seed metal, the peripheral edge of the semiconductor substrate may be processed into a substantially linear shape before performing the electrolytic plating, or the semiconductor substrate having such a shape may be used as a semiconductor substrate for forming a solar cell. It may be initially charged. When a semiconductor substrate having a substantially linear peripheral edge is used, if the edge corresponding to the main electrode of the seed metal is set to about 5 mm or less from the peripheral edge of the semiconductor substrate, the main electrode of the surface electrode is formed by electrolytic plating. This is preferable because the thickness of the plated film further increases.

The shape of the back electrode formed by electrolytic plating is formed so as to correspond to the shape of the seed metal as described above. The thickness of the back electrode finally obtained is about 1 to 10 μm.

More specifically, the solar cell manufacturing method of the present invention can be used to complete a solar cell by using it as a part of the following series of solar cell manufacturing steps. (1) a step of chemically etching the thickness of the solar cell manufacturing substrate (P-type) that has been initially charged to the thickness of the final solar cell; (2) a step of forming an oxide film on both surfaces of the substrate by the first oxidation step; (3) a step of protecting only the back surface side of the light receiving surface of the substrate with a masking agent such as a resist or an acid-resistant tape, and then removing only the oxide film on the light receiving surface side using, for example, HF; An N-type diffusion layer is formed only on the light receiving surface by diffusing a type impurity, for example, phosphorus, and then,
(5) a step of forming a resist pattern for forming a surface electrode having a desired shape on a light receiving surface of the substrate by a photolithography technique in a subsequent step;

(6) A step of forming a seed metal to be a base of the plated electrode with a view to forming a surface electrode on the seed metal by electrolytic plating in a later step, and removing the resist by a lift-off step; A) a step of forming a seed metal serving as a base for the plated electrode with the purpose of producing a back electrode on the seed metal by electrolytic plating in a later step; and (8) forming a seed metal on the front and back surfaces of the substrate by electrolytic plating. The process of plating metal and completing the front and back electrodes

(9) a step of forming an antireflection film on the front surface side of the substrate to reduce the reflection of light; (10) a step of performing a heat treatment to increase the degree of adhesion between the front electrode and the back electrode and the substrate; ) Dicing to final solar cell dimensions.

At any stage of the above process before cutting into a final size, the substrate may be cut into a shape and size that can be easily processed in a subsequent process. When the substrate dimensions in the initial state and the final solar cell dimensions are the same, the dicing step (11) may be omitted.

Hereinafter, a method for manufacturing a solar cell according to the present invention will be described.
This will be described with reference to the drawings. First Embodiment First, a P-type silicon substrate having a thickness of about 200 to 400 μm, which has been initially charged, is
The substrate is thinned to a thickness of 0 μm by, for example, chemical etching using NaOH. Next, a silicon oxide film having a thickness of about 3000 ° is formed on both surfaces of the silicon substrate by thermal oxidation. Next, the substrate surface (light receiving surface)
The oxide film formed on the surface is dissolved and removed by a chemical treatment using, for example, HF for the purpose of diffusing the N-type impurity into the oxide film. Next, the substrate is processed in a diffusion furnace at about 800 ° C., and phosphorus in a diffusion atmosphere is thermally diffused on the substrate surface to form an N-type diffusion layer. The oxide film formed on the back surface of the substrate is removed by chemical treatment, for example, by dissolving with HF.

In order to form a surface electrode having a desired shape on the substrate surface in a later step, the surface electrode 51 shown in FIG.
A resist mask having an opening corresponding to is formed.

Subsequently, a metal serving as a seed metal for plating performed in a later step is formed on the surface of the substrate by a vapor deposition method. Here, Ti / Pd / Ag was used as the seed metal, and the film thickness was 2000/2000/5000. Next, the resist mask formed on the surface of the silicon substrate and the metal deposited on the surface are removed by a lift-off process. Thereafter, a metal serving as a seed metal for plating performed in a later step is formed on the back surface of the substrate by an evaporation method. Here, Al / Ti / Pd is used as the seed metal.
/ Ag, and the film thickness is 1500/2000/20
00 ° / 5000 °.

Subsequently, plating is performed on the seed metals 5 and 6 on the silicon substrate 1 by electrolytic plating using an electrolytic plating apparatus as shown in FIG. Here, the seed metals 5 and 6 formed on the silicon substrate 1 are used as cathodes, and a flat plate anode 8 made of silver with the same area as the silicon substrate 1 is arranged in parallel with the seed metal 6.
An anode 9 having a concave shape and a concave portion slightly smaller than the silicon substrate 1 and made of silver is arranged in parallel with the seed metal 5 and immersed in the plating solution 11. At this time, the temperature of the plating solution 11 was set to 40 to 60 ° C. In this state, 1-2 A / d
Ag is simultaneously plated on the seed metals 5 and 6 on the front and back surfaces of the silicon substrate 1 by applying a voltage at a current density of m ² .
The thickness of the plating film is set to 5.
About 0 μm, about 7 μm by the main electrode 52 and the electrode pad 54 arranged on the periphery of the silicon substrate 1.
It is about 1.0 μm on the back surface.

Next, an anti-reflection film is formed on the surface of the substrate using a two-layer oxide film of TiO ₂ / Al ₂ O ₃ for reducing light reflection. Subsequently, in order to increase the degree of adhesion between the front surface electrode and the back surface electrode and the silicon substrate 1, under an N ₂ atmosphere, 41
Heat treatment is performed at about 5 ° C. for about 30 minutes. Finally, FIG.
Along the dicing line A shown in FIG.
To the final solar cell dimensions.

Embodiment 2 After the resist mask formed on the surface of the silicon substrate and the metal deposited on the surface are removed by a lift-off process, the silicon substrate is removed from its peripheral portion 14 as shown in FIG. A solar cell element was produced in the same manner as in Embodiment 1 except that dicing was performed so that According to this embodiment, when the distance of the main electrode 52 in the surface electrode 51 from the peripheral edge of the silicon substrate is within about 5 mm, the plating thickness of the main electrode 52 further increases, and
It could be about μm.

[0035]

According to the present invention, there are provided a semiconductor substrate, a sub-electrode formed on the surface of the semiconductor substrate and collecting a current generated in the solar cell element, and a main electrode electrically connected to the sub-electrode. In manufacturing a solar cell including a front electrode and a back electrode, the main electrode is formed by electrolytic plating so as to be arranged on the peripheral portion of the semiconductor substrate. The thickness of the main electrode is reduced by utilizing the conventional method of electrolytic plating, in which the thickness of the sub-electrode is prevented from increasing due to the electrolytic plating. It is possible to manufacture a solar cell in which the film thickness can be increased and the area of the main electrode can be reduced, and in particular, the series resistance can be reduced.

In the case where the periphery of the semiconductor substrate on which the main electrode is provided is formed in a substantially linear shape, the main electrode can be formed closer to the periphery of the semiconductor substrate. Thus, the thickness of the main electrode can be increased, and the area of the main electrode can be further reduced.

Further, when a plurality of surface electrodes are formed on one semiconductor substrate, and the main electrodes of the respective surface electrodes are respectively arranged on the periphery of the semiconductor substrate, the area of the main electrodes can be reduced. The formed surface electrode can be formed at a time, and the manufacturing cost can be reduced.

Further, the semiconductor device faces the surface electrode on the semiconductor substrate,
In the case where electrolytic plating is performed using an anode having a convex shape in the direction of the semiconductor substrate in a portion corresponding to the main electrode of the front surface electrode, the thickness of the electrolytic plating on the peripheral portion of the semiconductor substrate is further increased. It is possible to form a film, and it is possible to manufacture a solar cell in which the area of the main electrode is reduced and the series resistance is further reduced.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing a surface electrode pattern formed in a method for manufacturing a solar cell of the present invention.

FIG. 2 is a schematic conceptual diagram of an apparatus for performing electrolytic plating performed in the method of manufacturing a solar cell according to the present invention.

FIG. 3 is a schematic plan view showing another arrangement of surface electrode patterns formed in the method for manufacturing a solar cell of the present invention.

FIG. 4 is a schematic cross-sectional process diagram for explaining a conventional solar cell manufacturing process.

FIG. 5 is a schematic cross-sectional process diagram for explaining a conventional solar cell manufacturing process.

FIG. 6 is a plan view showing a surface electrode pattern of the solar cell element.

FIG. 7 is a schematic plan view showing a surface electrode pattern formed in a conventional solar cell manufacturing method.

FIG. 8 is a schematic conceptual diagram of an apparatus for performing electrolytic plating performed in a conventional solar cell manufacturing method.

FIG. 9 is a schematic conceptual diagram of another apparatus for performing electrolytic plating performed in a conventional method of manufacturing a solar cell.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Silicon substrate (semiconductor substrate) 2 Oxide film 3 N type diffusion layer 4 Resist pattern 5, 6 Seed metal 7 Anti-reflection film 8, 9 Anode 10 Partition wall 11 Plating liquid 12 Plating tank 14 Peripheral part 51 Surface electrode 52 Main electrode 53 Sub Electrode 54 Electrode pad 61 Back electrode A Dicing line

Claims (4)

[Claims] 1. A front electrode comprising a semiconductor substrate, a sub-electrode formed on the surface of the semiconductor substrate and collecting a current generated by a solar cell element, a main electrode electrically connected to the sub-electrode, and a back electrode. A method of manufacturing a solar cell, comprising: forming a main electrode by electrolytic plating so as to be arranged on a peripheral portion of a semiconductor substrate when manufacturing the solar cell including: 2. The method for manufacturing a solar cell according to claim 1, wherein a peripheral portion of the semiconductor substrate on which the main electrode is disposed is formed substantially linearly. 3. The manufacturing of a solar cell according to claim 1, wherein a plurality of surface electrodes are formed on one semiconductor substrate, and a main electrode of each surface electrode is disposed on a peripheral portion of the semiconductor substrate. Method. 4. Electroplating is performed using an anode which faces a surface electrode on a semiconductor substrate and has a convex shape in the direction of the semiconductor substrate in a portion corresponding to a main electrode of the surface electrode. 4. The method for manufacturing a solar cell according to any one of Items 3 to 3.