JP2021174839A - Production method of solar battery and solar battery - Google Patents

Abstract

To provide a solar battery capable of simplifying its production process and achieving lower cost.SOLUTION: In a solar battery 1 of a back electrode type, a semiconductor layer 25, a transparent electrode layer 28, and a metal electrode layer 29 are formed in an area 7, and a semiconductor layer 35, a transparent electrode layer 38, and a metal electrode layer 39 are formed in an area 8. The solar battery includes an insulation layer 41 which covers the metal electrode layer 29 except a non-insulation area 41a, and a contact electrode 51 formed on the non-insulation area 41a. In the non-insulation area 41a the transparent electrode layer 28 and the metal electrode layer 29 are not formed. The contact electrode 51 is brought into contact with a side face of the transparent electrode layer 28, a side face of the metal electrode layer 29, and a side face of the insulation layer 41.SELECTED DRAWING: Figure 2A

Description

The present invention relates to a method for manufacturing a back electrode type (back contact type) solar cell and a back electrode type solar cell.

Patent Documents 1 to 3 disclose a technique for connecting two polar electrodes and a wiring member in a back surface electrode type solar cell. Patent Documents 1 and 2 describe in a back electrode type solar cell.
-Has first and second wires that intersect the first and second electrodes,
-The first wiring is connected to the first electrode at the point where it intersects with the first electrode, and is insulated from the second electrode by an insulating layer at the point where it intersects with the second electrode.
The second wiring is connected to the second electrode at the point where it intersects with the second electrode, and is insulated from the first electrode by an insulating layer at the point where it intersects with the first electrode.
It is stated that.

Further, in Patent Document 3, in the back electrode type solar cell,
-Has p-electrode wiring and n-electrode wiring that intersect the p-electrode and n-electrode.
・ Insulating resin is formed on the back side,
The wiring for the p electrode is connected to the p electrode by the conductive member in the hole of the insulating resin at the point where it intersects with the p electrode, and is insulated from the n electrode by the insulating resin at the point where it intersects with the n electrode.
The n-electrode wiring is connected to the n-electrode by a conductive member in the hole of the insulating resin at the point where it intersects with the n-electrode, and is insulated from the p-electrode by the insulating resin at the point where it intersects with the p-electrode.
It is stated that.

JP-A-2018-133567 Japanese Unexamined Patent Publication No. 2015-159286 Japanese Unexamined Patent Publication No. 2014-127550

The inventors of the present application aim to simplify and reduce the cost of such a solar cell manufacturing process.

An object of the present invention is to provide a method for manufacturing a solar cell and a solar cell capable of simplifying the manufacturing process and reducing the cost.

The method for manufacturing a solar cell according to the present invention includes a first conductive type semiconductor layer, a first transparent electrode layer, and a first transparent electrode layer, which are sequentially laminated on a semiconductor substrate and a first region which is a part of one main surface side of the semiconductor substrate. It includes a metal electrode layer, a second conductive semiconductor layer, a second transparent electrode layer, and a second metal electrode layer, which are sequentially laminated in a second region which is a part of the other main surface side of the semiconductor substrate. A method for manufacturing a back electrode type solar cell, in which a series of transparent electrode layer material films are formed on the first conductive type semiconductor layer and the second conductive type semiconductor layer on the one main surface side of the semiconductor substrate. The transparent electrode layer material film forming step to be formed, the metal electrode layer material film forming step of forming a series of metal electrode layer material films on the transparent electrode layer material film, and the metal electrode layer material in the first region. A first insulating layer that completely covers the film except for the first non-insulating region, and a second insulating layer that completely covers the metal electrode layer material film in the second region except for the second non-insulating region. The first insulating layer is formed by forming the first insulating layer and the second insulating layer that are separated from each other, and an etching method using the first insulating layer and the second insulating layer as masks. The exposed portion of the metal electrode layer material film and the transparent electrode layer material corresponding to the exposed portion between the insulating layer and the second insulating layer, and in the first non-insulated region and the second non-insulated region. By removing the film, the first transparent electrode layer and the first metal electrode layer patterned in the first region are formed, and the second transparent electrode layer and the second transparent electrode layer patterned in the second region are formed. A step of forming a transparent electrode layer and a metal electrode layer that forms a second metal electrode layer and leaves the first insulating layer and the second insulating layer without removing them, and the first transparent electrode in the first non-insulating region. The first contact electrode is formed so as to be in contact with the side surface of the layer, the side surface of the first metal electrode layer, and the side surface of the first insulating layer, and the side surface of the second transparent electrode layer, the side surface of the second transparent electrode layer, is formed in the second non-insulating region. It includes a contact electrode forming step of forming the second contact electrode so as to be in contact with the side surface of the second metal electrode layer and the side surface of the second insulating layer.

The solar cell according to the present invention includes a semiconductor substrate, a first conductive semiconductor layer, a first transparent electrode layer, and a first metal electrode that are sequentially laminated in a first region that is a part of one main surface side of the semiconductor substrate. A back electrode type including a layer and a second conductive type semiconductor layer, a second transparent electrode layer, and a second metal electrode layer which are sequentially laminated in a second region which is a part of the other main surface side of the semiconductor substrate. The first insulating layer formed in the first region and the second metal electrode layer so as to cover the first metal electrode layer as a whole except for the first non-insulating region. The second insulating layer formed in the second region so as to cover the entire area except for the non-insulated region, the first contact electrode formed in the first non-insulated region, and the second non-insulated region. A second contact electrode formed is provided. The first transparent electrode layer and the first metal electrode layer are not formed in the first non-insulated region, and the second transparent electrode layer and the second metal electrode are formed in the second non-insulated region. The layer is not formed, and the first contact electrode is in contact with the side surface of the first transparent electrode layer, the side surface of the first metal electrode layer, and the side surface of the first insulating layer, and the second contact electrode. Is in contact with the side surface of the second transparent electrode layer, the side surface of the second metal electrode layer, and the side surface of the second insulating layer.

According to the present invention, the manufacturing process of a solar cell can be simplified and the cost can be reduced.

It is the figure which looked at the solar cell which concerns on this embodiment from the back side. FIG. 5 is a cross-sectional view taken along the line IIA-IIA of the solar cell of FIG. FIG. 2 is a cross-sectional view taken along the line IIB-IIB of the solar cell of FIG. It is a figure which shows the semiconductor layer formation process in the manufacturing method of the solar cell which concerns on this embodiment. It is a figure which shows the electrode layer material film formation | transparent electrode layer material film formation | metal electrode layer material film formation | metal electrode layer material film formation step in the manufacturing method of the solar cell which concerns on this embodiment. It is a figure which shows the insulation layer formation process in the manufacturing method of the solar cell which concerns on this embodiment. It is a figure which shows the electrode layer formation process, that is, the transparent electrode layer formation process, and the metal electrode layer formation process in the manufacturing method of the solar cell which concerns on this embodiment. It is a figure which shows the contact electrode forming process in the manufacturing method of the solar cell which concerns on this embodiment. It is sectional drawing of the solar cell which concerns on modification 1 of this Embodiment, and is the sectional view corresponding to line IIA-IIA in FIG. It is sectional drawing of the solar cell which concerns on modification 1 of this Embodiment, and is the sectional view corresponding to line IIA-IIA in FIG. FIG. 5 is an enlarged view of a first non-insulated region of a first insulating layer on the back surface side of the solar cell according to the second modification of the present embodiment. It is an enlarged view of the 1st non-insulating region of the 1st insulating layer on the back surface side of the solar cell which concerns on modification 3 of this embodiment. It is an enlarged view of the 1st non-insulating region of the 1st insulating layer on the back surface side of the solar cell which concerns on the modification 4 of this embodiment. It is an enlarged view of the 1st non-insulating region of the 1st insulating layer on the back surface side of the solar cell which concerns on the modification 5 of this embodiment. It is an enlarged view of the 1st non-insulating region of the 1st insulating layer on the back surface side of the solar cell which concerns on the modification 6 of this embodiment. It is sectional drawing of the solar cell which concerns on Comparative Examples 1 and 2, and is the sectional view corresponding to line IIA-IIA in FIG. It is sectional drawing of the solar cell which concerns on Comparative Examples 1 and 2, and is the sectional view corresponding to line IIB-IIB in FIG. It is a figure which shows the transparent electrode layer material film forming step, the metal electrode layer material film forming step, and the insulating layer forming step in the manufacturing method of the solar cell which concerns on Comparative Example 1. It is a figure which shows the contact electrode forming process in the manufacturing method of the solar cell which concerns on Comparative Example 1. It is a figure which shows the electrode layer formation step in the manufacturing method of the solar cell which concerns on Comparative Example 1, that is, the transparent electrode layer formation step and the metal electrode layer formation step. FIG. 7A is an enlarged view showing a partial VIID in the manufacturing process of the solar cell shown in FIG. 7A. It is a figure which shows the transparent electrode layer material film forming process, the metal electrode layer material film forming process, and the contact electrode forming process in the manufacturing method of the solar cell which concerns on Comparative Example 2. It is a figure which shows the insulation layer formation process in the manufacturing method of the solar cell which concerns on Comparative Example 2. It is a figure which shows the electrode layer formation process, that is, the transparent electrode layer formation process, and the metal electrode layer formation process in the manufacturing method of the solar cell which concerns on Comparative Example 2.

Hereinafter, an example of the embodiment of the present invention will be described with reference to the accompanying drawings. In addition, the same reference numerals are given to the same or corresponding parts in each drawing. In addition, for convenience, hatching, member codes, and the like may be omitted, but in such cases, other drawings shall be referred to.

(Solar cell of this embodiment)
FIG. 1 is a view of the solar cell according to the present embodiment as viewed from the back surface side. FIG. 2A is a sectional view taken along line IIA-IIA of the solar cell of FIG. 1, and FIG. 2B is a sectional view taken along line IIB-IIB of the solar cell of FIG. The solar cell 1 shown in FIGS. 1, 2A and 2B is a back electrode type (also referred to as a back contact type or a back surface bonding type) and a heterojunction type solar cell.

The solar cell 1 includes a semiconductor substrate 11 having two main surfaces, and has a first region 7 and a second region 8 on the main surface of the semiconductor substrate 11. In the following, the main surface of the main surface of the semiconductor substrate 11 on the light receiving side is the light receiving surface, and the main surface of the main surface of the semiconductor substrate 11 opposite to the light receiving surface (one main surface) is the back surface.

The first region 7 has a band-like shape and extends in the Y direction (second direction). Similarly, the second region 8 has a band-like shape and extends in the Y direction. The first region 7 and the second region 8 are alternately provided in the X direction (first direction) intersecting the Y direction.

As shown in FIGS. 2A and 2B, the solar cell 1 includes a passivation layer 13 and an optical adjustment layer 15 which are sequentially laminated on the light receiving surface side of the semiconductor substrate 11. Further, the solar cell 1 includes a passivation layer 23, a first conductive semiconductor layer 25, a first electrode layer 27, and a first insulating layer 41, which are sequentially laminated on a part (first region 7) on the back surface side of the semiconductor substrate 11. To be equipped. Further, the solar cell 1 includes a passivation layer 33, a second conductive semiconductor layer 35, a second electrode layer 37, and a second insulation laminated in order on another part (second region 8) on the back surface side of the semiconductor substrate 11. It includes a layer 42. Further, the solar cell 1 includes a first contact electrode 51 corresponding to the first electrode layer 27 and a second contact electrode 52 corresponding to the second electrode layer 37.

The semiconductor substrate 11 is formed of a crystalline silicon material such as single crystal silicon or polycrystalline silicon. The semiconductor substrate 11 is, for example, an n-type semiconductor substrate in which a crystalline silicon material is doped with an n-type dopant. The semiconductor substrate 11 may be, for example, a p-type semiconductor substrate in which a crystalline silicon material is doped with a p-type dopant. Examples of the n-type dopant include phosphorus (P). Examples of the p-type dopant include boron (B). The semiconductor substrate 11 functions as a photoelectric conversion substrate that absorbs incident light from the light receiving surface side to generate optical carriers (electrons and holes).

By using crystalline silicon as the material of the semiconductor substrate 11, a relatively high output (stable output regardless of the illuminance) can be obtained even when the dark current is relatively small and the intensity of the incident light is low.

The passivation layer 13 is formed on the light receiving surface side of the semiconductor substrate 11. The passivation layer 23 is formed in the first region 7 on the back surface side of the semiconductor substrate 11. The passivation layer 33 is formed in the second region 8 on the back surface side of the semiconductor substrate 11. The passivation layers 13, 23, 33 are formed of, for example, a material containing an intrinsic (i-type) amorphous silicon material as a main component. The passivation layers 13, 23, 33 suppress the recombination of carriers generated in the semiconductor substrate 11 and increase the carrier recovery efficiency.

The optical adjustment layer 15 is formed on the passivation layer 13 on the light receiving surface side of the semiconductor substrate 11. The optical adjustment layer 15 functions as an antireflection layer that prevents reflection of incident light, and also functions as a protective layer that protects the light receiving surface side of the semiconductor substrate 11 and the passivation layer 13. The optical adjustment layer 15 is formed of an insulating material such as a composite thereof such as silicon oxide (SiO), silicon nitride (SiN), or silicon oxynitride (SiON).

The first conductive semiconductor layer 25 is formed on the passivation layer 23, that is, in the first region 7 on the back surface side of the semiconductor substrate 11. On the other hand, the second conductive semiconductor layer 35 is formed on the passivation layer 33, that is, in the second region 8 on the back surface side of the semiconductor substrate 11. That is, the first conductive semiconductor layer 25 and the second conductive semiconductor layer 35 have a band-like shape and extend in the Y direction. The first conductive semiconductor layer 25 and the second conductive semiconductor layer 35 are alternately arranged in the X direction. A part of the second conductive semiconductor layer 35 may overlap a part of the adjacent first conductive semiconductor layer 25 (not shown).

The first conductive semiconductor layer 25 is formed of, for example, an amorphous silicon material. The first conductive semiconductor layer 25 is, for example, a p-type semiconductor layer in which an amorphous silicon material is doped with a p-type dopant (for example, the above-mentioned boron (B)).

The second conductive semiconductor layer 35 is formed of, for example, an amorphous silicon material. The second conductive semiconductor layer 35 is, for example, an n-type semiconductor layer in which an amorphous silicon material is doped with an n-type dopant (for example, phosphorus (P) described above). The first conductive semiconductor layer 25 may be an n-type semiconductor layer, and the second conductive semiconductor layer 35 may be a p-type semiconductor layer.

The first electrode layer 27 is formed on the first conductive semiconductor layer 25, that is, in the first region 7 on the back surface side of the semiconductor substrate 11. On the other hand, the second electrode layer 37 is formed on the second conductive semiconductor layer 35, that is, in the second region 8 on the back surface side of the semiconductor substrate 11. That is, the first electrode layer 27 and the second electrode layer 37 have a band-like shape and extend in the Y direction. The first electrode layer 27 and the second electrode layer 37 are provided alternately in the X direction.

The first electrode layer 27 has a first transparent electrode layer 28 and a first metal electrode layer 29 that are sequentially laminated on the first conductive semiconductor layer 25. On the other hand, the second electrode layer 37 has a second transparent electrode layer 38 and a second metal electrode layer 39 which are sequentially laminated on the second conductive semiconductor layer 35.

The first transparent electrode layer 28 and the second transparent electrode layer 38 are formed of a transparent conductive material. Examples of the transparent conductive material include ITO (Indium Tin Oxide: a composite oxide of indium tin oxide and tin oxide), ZnO (Zinc Oxide: zinc oxide) and the like.

The first metal electrode layer 29 and the second metal electrode layer 39 include a metal material such as silver, copper, and aluminum formed by a PVD method such as sputtering or a plating method, for example. Among these, as the metal material, Cu, which is an inexpensive material as compared with the known conductive paste material containing Ag powder, is preferable.

The first insulating layer 41 is formed on the first metal electrode layer 29, that is, in the first region 7 on the back surface side of the semiconductor substrate 11. The second insulating layer 42 is formed on the second metal electrode layer 39, that is, in the second region 8 on the back surface side of the semiconductor substrate 11. That is, as shown in FIG. 1, the first insulating layer 41 and the second insulating layer 42 have a band-like shape and extend in the Y direction. The first insulating layer 41 and the second insulating layer 42 are alternately provided in the X direction.

The first insulating layer 41 covers the first metal electrode layer 29 as a whole except for the first non-insulating region 41a. Similarly, the second insulating layer 42 covers the second metal electrode layer 39 as a whole except for the second non-insulating region 42a.

The first insulating layer 41, the first metal electrode layer 29, and the first transparent electrode layer 28 are not formed in the first non-insulating region 41a. That is, the first non-insulated region 41a is composed of openings that expose the surface of the first conductive semiconductor layer 25, the side surface of the first transparent electrode layer 28, and the side surface of the first metal electrode layer 29. The first non-insulated region 41a is arranged on a first straight line X1 extending in the X direction (first direction).

Similarly, the second insulating layer 42, the second metal electrode layer 39, and the second transparent electrode layer 38 are not formed in the second non-insulating region 42a. That is, the second non-insulating region 42a is composed of openings that expose the surface of the second conductive semiconductor layer 35, the side surface of the second transparent electrode layer 38, and the side surface of the second metal electrode layer 39. The second non-insulated region 42a is arranged on a second straight line X2 different from the first straight line X1 extending in the X direction (first direction).

The first straight line X1 and the second straight line X2 intersect the first electrode layer 27 and the second electrode layer 37, and are alternately arranged in the Y direction (second direction).

Examples of the material of the first insulating layer 41 and the second insulating layer 42 include composites thereof such as silicon oxide (SiO), silicon nitride (SiN), and silicon oxynitride (SiON). Further, for example, a thermosetting resin such as an epoxy resin type or a resin ester type that can be applied and fired by screen printing can also be used. Inorganic particles such as silica or talc may be mixed with these resins for the purpose of improving printability or chemical resistance.

A first contact electrode 51 is formed in the first non-insulating region 41a of the first insulating layer 41, and a second contact electrode 52 is formed in the second non-insulating region 42a of the second insulating layer 42. There is. That is, the first contact electrode 51 is arranged on the first straight line X1, and the second contact electrode 52 is arranged on the second straight line X2.

The first contact electrode 51 is in contact with the surface of the first conductive semiconductor layer 25, the side surface of the first transparent electrode layer 28, the side surface of the first metal electrode layer 29, and the side surface of the first insulating layer 41. On the other hand, the second contact electrode 52 is in contact with the surface of the second conductive semiconductor layer 35, the side surface of the second transparent electrode layer 38, the side surface of the second metal electrode layer 39, and the side surface of the second insulating layer 42.

The surface of the first conductive semiconductor layer 25 in the first non-insulated region 41a is oxidized, and the first contact electrode 51 may be in contact with the oxide layer 25o on the surface of the first conductive semiconductor layer 25. .. Similarly, the surface of the second conductive semiconductor layer 35 in the second non-insulated region 42a is oxidized, and the second contact electrode 52 may be in contact with the oxide layer 35o on the surface of the second conductive semiconductor layer 35. good.

The first contact electrode 51 and the second contact electrode 52 are formed by printing and curing a printing material containing a particulate metal material such as Cu, Ag, or Al, a resin material, and a solvent. Among these, as the printing material, an Ag paste material is preferable from the viewpoint of contactability with solder for connection with a wiring member.

The width of the first non-insulating region 41a of the first insulating layer 41 in the Y direction (second direction), that is, the width of the first contact electrode 51 in the Y direction (second direction) is larger than the width of the first wiring member 91. big. Similarly, the width of the second non-insulated region 42a in the Y direction (second direction), that is, the width of the second contact electrode 52 in the Y direction (second direction) is larger than the width of the second wiring member 92. For example, the width of the first non-insulated region 41a and the second non-insulated region 42a, that is, the width of the first contact electrode 51 and the second contact electrode 52 is 1 mm or more and 50 mm or less. According to this, it is possible to secure the alignment clearance at the time of connecting the wiring members.

As shown in FIGS. 1, 2A and 2B, the first electrode layer 27 and the second electrode layer 37 are separated at the boundary between the first region 7 and the second region 8. That is, the first transparent electrode layer 28 and the second transparent electrode layer 38 are separated from each other, and the first metal electrode layer 29 and the second metal electrode layer 39 are separated from each other. Further, the first insulating layer 41 and the second insulating layer 42 are separated from each other.

The region between the first transparent electrode layer 28 and the second transparent electrode layer 38, that is, the region between the first metal electrode layer 29 and the second metal electrode layer 39 is the first insulating layer 41 and the second insulating layer. Not covered with 42.

In the first metal electrode layer 29, the main surface opposite to the main surface in contact with the first transparent electrode layer 28 is covered with the first insulating layer 41. Similarly, in the second metal electrode layer 39, the main surface opposite to the main surface in contact with the second transparent electrode layer 38 is covered with the second insulating layer 42.

On the other hand, the side surface of the first metal electrode layer 29 and the side surface of the first transparent electrode layer 28 are not covered with the first insulating layer 41. Similarly, the side surface of the second metal electrode layer 39 and the side surface of the second transparent electrode layer 38 are not covered with the second insulating layer 42.

As shown in FIG. 1, the first wiring member 91 extends in the X direction (first direction) along the first straight line X1. Similarly, the second wiring member 92 extends in the X direction (first direction) along the second straight line X2. That is, the first wiring member 91 and the second wiring member 92 intersect the first electrode layer 27 and the second electrode layer 37, and are alternately arranged in the Y direction (second direction).

The first wiring member 91 is electrically connected to the first electrode layer 27 by the first contact electrode 51 in the first non-insulated region 41a of the first insulating layer 41, and is connected to the second electrode layer 37 by the second insulating layer 42. It is electrically insulated. Similarly, the second wiring member 92 is electrically connected to the second electrode layer 37 by the second contact electrode 52 in the second non-insulated region 42a of the second insulating layer 42, and the first electrode is connected by the first insulating layer 41. It is electrically insulated from the layer 27.

The center distance (pitch) between the first wiring member 91 and the second wiring member 92 in the Y direction is larger than the center distance (pitch) between the first electrode layer 27 and the second electrode layer 37 in the X direction. For example, the center distance (pitch) between the first wiring member 91 and the second wiring member 92 is 5 mm or more and 50 mm or less. According to this, the current path flowing through the electrode layer can be shortened, the output loss due to the electrode resistance can be reduced, and the power generation efficiency of the solar cell can be improved.

Examples of the first wiring member 91 and the second wiring member 92 include known tab wires and the like.

Here, the inventors of the present application have made the insulating layers 41, 42 for ensuring insulation and contact with the wiring members 91, 92 for the purpose of simplifying the manufacturing process of such a solar cell and reducing the cost. It is devised that the contact electrodes 51 and 52 are also used as a resist for etching the electrode layers 27 and 37, that is, the metal electrode layers 29 and 39 and the transparent electrode layers 28 and 38. Hereinafter, the manufacturing process of the electrode layer devised by the inventors of the present application will be described as Comparative Examples 1 and 2.

(Solar cells of Comparative Examples 1 and 2)
FIG. 6A is a cross-sectional view of the solar cell according to Comparative Examples 1 and 2, which is a cross-sectional view corresponding to the line IIA-IIA in FIG. 1, and FIG. 6B is a cross-sectional view of the solar cell according to Comparative Examples 1 and 2. It is a cross-sectional view corresponding to the line IIB-IIB in FIG. The solar cells 1X of Comparative Examples 1 and 2 shown in FIGS. 6A and 6B are mainly also in the first non-insulated region 41a of the first insulating layer 41X as compared with the solar cells 1 shown in FIGS. 2A and 2B. , The first electrode layer 27X, that is, the first transparent electrode layer 28X and the first metal electrode layer 29X, and the first contact electrode 51X is the first metal of the first electrode layer 27X in the first non-insulated region 41a. The second electrode layer 37X, that is, the second transparent electrode layer 38X and the second metal electrode layer 39X, are also formed at the points formed on the electrode layer 29X and in the second non-insulating region 42a of the second insulating layer 42X. The second contact electrode 52X is formed on the second metal electrode layer 39X of the second electrode layer 37X in the second non-insulated region 42a, which is different from the present embodiment.

(Manufacturing method of solar cell of Comparative Example 1)
Hereinafter, the manufacturing process of the electrode layers 27X and 37X in the method for manufacturing the solar cell of Comparative Example 1 will be mainly described with reference to FIGS. 7A to 7C. In the manufacturing process of the electrode layers 27X and 37X of Comparative Example 1, after the insulating layers 41X and 42X are formed, the contact electrodes 51X and 52X are formed, and then the insulating layers 41X and 42X and the contact electrodes 51X and 52X are used as masks. The electrode layers 27X and 37X, that is, the metal electrode layers 29X and 39X and the transparent electrode layers 28X and 38X are patterned.

FIG. 7A is a diagram showing a transparent electrode layer material film forming step, a metal electrode layer material film forming step, and an insulating layer forming step in the method for manufacturing a solar cell according to Comparative Example 1, and FIG. 7B is a diagram showing Comparative Example 1 It is a figure which shows the contact electrode forming process in the manufacturing method of a solar cell. Further, FIG. 7C is a diagram showing an electrode layer forming step, that is, a transparent electrode layer forming step and a metal electrode layer forming step in the method for manufacturing a solar cell according to Comparative Example 1. 7A to 7C show the back surface side of the semiconductor substrate 11, and omit the front surface side of the semiconductor substrate 11.

First, as shown in FIG. 7A, a series of transparent electrode layer material films 28Z are formed on the first conductive semiconductor layer 25 and the second conductive semiconductor layer 35 by using, for example, the CVD method or the PVD method. (Transparent electrode layer material film forming step). Next, using a PVD method such as sputtering or a plating method, a series of metal electrode layers are placed on the transparent electrode layer material film 28Z, that is, across the first conductive semiconductor layer 25 and the second conductive semiconductor layer 35. A material film 29Z is formed (metal electrode layer material film forming step).

Next, the first insulating layer 41X is placed on the first conductive semiconductor layer 25 via the transparent electrode layer material film 28Z and the metal electrode layer material film 29Z, that is, in the first region 7, except for the first non-insulating region 41a. To form. Further, the second insulating layer 42X is provided on the second conductive semiconductor layer 35 via the transparent electrode layer material film 28Z and the metal electrode layer material film 29Z, that is, in the second region 8 except for the second non-insulating region 42a. Form (insulating layer forming step). The first insulating layer 41X and the second insulating layer 42X are formed so as to be separated from each other.

For example, by printing a printing material containing a resin material and a solvent using a pattern printing method such as press printing such as screen printing or gravure printing, or ejection printing such as inkjet printing, and firing (curing) the printing material. The first insulating layer 41X and the second insulating layer 42X are formed.

Next, as shown in FIG. 7B, the first contact electrode 51X is formed in the first non-insulating region 41a of the first insulating layer 41X, and the second contact electrode 52X is formed in the second non-insulating region 42a of the second insulating layer 42X. (Contact electrode forming step). For example, using a pattern printing method such as press printing such as screen printing or gravure printing, or ejection printing such as inkjet printing, a printing material containing Ag particles, a resin material and a solvent, that is, an Ag paste material is printed. By firing (curing), the first contact electrode 51X and the second contact electrode 52X are formed.

Next, as shown in FIG. 7C, the metal electrode layer material film 29Z is used by an etching method using the first insulating layer 41X and the first contact electrode 51X, and the second insulating layer 42X and the second contact electrode 52X as masks. The first transparent electrode layer 28X and the second transparent electrode layer 38X separated from each other by patterning the transparent electrode layer material film 28Z, and the first metal electrode layer 29X and the second metal electrode layer 39X separated from each other. (Electrode layer forming step). As a result, the first electrode layer 27X and the second electrode layer 37X are formed. At this time, the first insulating layer 41X and the second insulating layer 42X are left without being removed.

FIG. 7D is an enlarged view showing a partial VIID in the manufacturing process of the solar cell shown in FIG. 7A. As shown in FIG. 7D, in Comparative Example 1, when the printing material for the first insulating layer 41X (and the second insulating layer 42X) is fired (cured), the resin material in the printing material exudes. The resin film 41Z covers a part (for example, a valley portion of the uneven structure (texture structure)) of the metal electrode layer material film 29Z in the first non-insulating region 41a (and the second non-insulating region 42a). There is. Then, the contact area between the first contact electrode 51X and the first metal electrode layer 29X formed in the first non-insulating region 41a becomes smaller, and the resistance increases (decreased contact property). Further, the contact area between the second contact electrode 52X and the second metal electrode layer 39X formed in the second non-insulating region 42a becomes smaller, and the resistance increases (decreased contact property).

(Manufacturing method of solar cell of Comparative Example 2)
Next, the manufacturing process of the electrode layers 27X and 37X in the method for manufacturing the solar cell of Comparative Example 2 will be mainly described with reference to FIGS. 8A to 8C. In the manufacturing process of the electrode layers 27X and 37X of Comparative Example 2, the forming order of the insulating layers 41X and 42X and the contact electrodes 51X and 52X is opposite to that of Comparative Example 1. That is, in the manufacturing process of the electrode layers 27X and 37X of Comparative Example 2, after forming the contact electrodes 51X and 52X, the insulating layers 41X and 42X are formed, and then the insulating layers 41X and 42X and the contact electrodes 51X and 52X are masked. The electrode layers 27X and 37X, that is, the metal electrode layers 29X and 39X and the transparent electrode layers 28X and 38X are patterned.

FIG. 8A is a diagram showing a transparent electrode layer material film forming step, a metal electrode layer material film forming step, and a contact electrode forming step in the method for manufacturing a solar cell according to Comparative Example 2, and FIG. 8B is a diagram showing Comparative Example 2 It is a figure which shows the insulation layer formation process in the manufacturing method of a solar cell. Further, FIG. 8C is a diagram showing an electrode layer forming step, that is, a transparent electrode layer forming step and a metal electrode layer forming step in the method for manufacturing a solar cell according to Comparative Example 2. 8A to 8C also show the back surface side of the semiconductor substrate 11, and omit the front surface side of the semiconductor substrate 11.

First, as shown in FIG. 8A, a series of transparent electrode layer materials straddling the first conductive type semiconductor layer 25 and the second conductive type semiconductor layer 35 by using, for example, a CVD method or a PVD method in the same manner as described above. A film 28Z is formed (transparent electrode layer material film forming step). Next, using a PVD method such as sputtering or a plating method, a series of metal electrode layers are placed on the transparent electrode layer material film 28Z, that is, across the first conductive semiconductor layer 25 and the second conductive semiconductor layer 35. A material film 29Z is formed (metal electrode layer material film forming step).

Next, the first contact electrode 51X is formed in a region corresponding to the first non-insulating region 41a of the first insulating layer 41X, which will be described later. Further, the second contact electrode 52X is formed in the region corresponding to the second non-insulating region 42a of the second insulating layer 42X (contact electrode forming step). For example, as described above, using a pattern printing method such as press printing such as screen printing or gravure printing, or ejection printing such as inkjet printing, a printing material containing Ag particles, a resin material and a solvent, that is, an Ag paste material. Is printed and fired (cured) to form a first contact electrode 51X and a second contact electrode 52X.

Next, as shown in FIG. 8B, the first non-insulating region 41a is formed on the first conductive semiconductor layer 25 via the transparent electrode layer material film 28Z and the metal electrode layer material film 29Z, that is, in the first region 7. Except for this, the first insulating layer 41X is formed. Further, the second insulating layer 42X is provided on the second conductive semiconductor layer 35 via the transparent electrode layer material film 28Z and the metal electrode layer material film 29Z, that is, in the second region 8 except for the second non-insulating region 42a. Form (insulating layer forming step). The first insulating layer 41X and the second insulating layer 42X are formed so as to be separated from each other.

For example, as described above, a printing material containing a resin material and a solvent is printed and fired (cured) by using a pattern printing method such as press printing such as screen printing or gravure printing, or ejection printing such as inkjet printing. By doing so, the first insulating layer 41X and the second insulating layer 42X are formed.

Next, as shown in FIG. 8C, a metal electrode is used by using an etching method using the first insulating layer 41X and the first contact electrode 51X, and the second insulating layer 42X and the second contact electrode 52X as masks, as described above. The first transparent electrode layer 28X and the second transparent electrode layer 38X separated from each other by patterning the layer material film 29Z and the transparent electrode layer material film 28Z, and the first metal electrode layer 29X and the second separated from each other. The metal electrode layer 39X is formed (electrode layer forming step). As a result, the first electrode layer 27X and the second electrode layer 37X are formed. At this time, the first insulating layer 41X and the second insulating layer 42X are left without being removed.

In Comparative Example 2, as shown in FIG. 8B, since the portion A around the contact electrode is narrow, the insulating layers 41X and 42X may not be properly formed in this portion A (decrease in stability of the manufacturing process).

Regarding these points, the inventors of the present application can reduce the deterioration of the contact property between the contact electrode and the metal electrode layer even if the manufacturing process is simplified and the cost is reduced, and the manufacturing process can be reduced. We devise a method for manufacturing a solar cell that can reduce the decrease in stability.

(Manufacturing method of solar cell of this embodiment)
Hereinafter, a method for manufacturing a solar cell according to the present embodiment will be described with reference to FIGS. 3A to 3E. FIG. 3A is a diagram showing a semiconductor layer forming step in the solar cell manufacturing method according to the present embodiment, and FIG. 3B is an electrode layer material film forming step in the solar cell manufacturing method according to the present embodiment, that is, a transparent electrode. It is a figure which shows the layer material film forming process and the metal electrode layer material film forming process. Further, FIG. 3C is a diagram showing an insulating layer forming step in the solar cell manufacturing method according to the present embodiment, and FIG. 3D is an electrode layer forming step in the solar cell manufacturing method according to the present embodiment, that is, a transparent electrode. It is a figure which shows the layer formation process and the metal electrode layer formation process. Further, FIG. 3E is a diagram showing a contact electrode forming step in the method for manufacturing a solar cell according to the present embodiment. 3A to 3E show the back surface side of the semiconductor substrate 11, and omit the front surface side of the semiconductor substrate 11.

First, as shown in FIG. 3A, a passivation layer 23 and a first conductive semiconductor layer 25 are formed on a part of the back surface side of the semiconductor substrate 11, specifically in the first region 7 (semiconductor layer forming step). .. For example, a passivation layer material film and a first conductive semiconductor layer material film are formed on all the back surfaces of the semiconductor substrate 11 by using a CVD method or a PVD method, and then generated by using a photolithography technique or a printing technique. The passivation layer 23 and the first conductive semiconductor layer 25 may be patterned by an etching method using a resist or a metal mask.

Examples of the etching solution for the p-type semiconductor layer material film include hydrofluoric acid containing ozone, and an acidic solution such as a mixed solution of nitric acid and hydrofluoric acid. Examples of the etching solution for the n-type semiconductor layer material film include hydrofluoric acid. For example, an alkaline solution such as an aqueous solution of potassium hydroxide can be mentioned.

Alternatively, when the passivation layer and the first conductive semiconductor layer are laminated on the back surface side of the semiconductor substrate 11 by using the CVD method or the PVD method, a mask is used to form the passivation layer 23 and the first conductive semiconductor layer 25. Film formation and patterning may be performed at the same time.

Next, the passivation layer 33 and the second conductive semiconductor layer 35 are formed on the other part of the back surface side of the semiconductor substrate 11, specifically in the second region 8 (semiconductor layer forming step). For example, similarly to the above, a passivation layer material film and a second conductive semiconductor layer material film are formed on all the back surfaces of the semiconductor substrate 11 by using the CVD method or the PVD method, and then the photolithography technique or the printing technique is applied. The passivation layer 33 and the second conductive semiconductor layer 35 may be patterned by an etching method using the resist or the metal mask produced in the above.

Alternatively, when the passivation layer and the second conductive semiconductor layer are laminated on the back surface side of the semiconductor substrate 11 by using the CVD method or the PVD method, a mask is used to form the passivation layer 33 and the second conductive semiconductor layer 35. Film formation and patterning may be performed at the same time.

In this semiconductor layer forming step, the passivation layer 13 may be formed on the entire surface of the semiconductor substrate 11 on the light receiving surface side (not shown).

Next, as shown in FIG. 3B, a series of transparent electrode layer material films 28Z are formed on the first conductive semiconductor layer 25 and the second conductive semiconductor layer 35 so as to straddle them (transparent electrode layer material film forming step). ). As a method for forming the transparent electrode layer material film 28Z, for example, a CVD method or a PVD method is used.

Next, a series of metal electrode layer material films 29Z are formed on the transparent electrode layer material film 28Z, that is, across the first conductive semiconductor layer 25 and the second conductive semiconductor layer 35 (metal electrode layer material film forming step). ). As a method for forming the metal electrode layer material film 29Z, for example, a PVD method such as sputtering or a plating method is used.

Next, as shown in FIG. 3C, the first non-insulating region 41a is formed on the first conductive semiconductor layer 25 via the transparent electrode layer material film 28Z and the metal electrode layer material film 29Z, that is, in the first region 7. Except for this, the first insulating layer 41 is formed. Further, the second insulating layer 42 is provided on the second conductive semiconductor layer 35 via the transparent electrode layer material film 28Z and the metal electrode layer material film 29Z, that is, in the second region 8 except for the second non-insulating region 42a. Form (insulating layer forming step). The first insulating layer 41 and the second insulating layer 42 are formed so as to be separated from each other.

Examples of the method for forming the first insulating layer 41 and the second insulating layer 42 include a pattern printing method such as press printing such as screen printing or gravure printing, or ejection printing such as inkjet printing.

In the pattern printing method, a printing material containing a resin material and a solvent is printed and fired (cured) to form a first insulating layer 41X and a second insulating layer 42X. At this time, as described above, the resin film exuded from the resin material in the printing material is a part of the metal electrode layer material film 29Z in the first non-insulating region 41a and the second non-insulating region 42a (for example, an uneven structure). (Tanibe of (texture structure)) or the whole may be covered.

Next, as shown in FIG. 3D, an etching method using the first insulating layer 41 and the second insulating layer 42 as masks is used between the first insulating layer 41 and the second insulating layer 42, and first. By removing the exposed portion of the metal electrode layer material film 29Z and the transparent electrode layer material film 28Z corresponding to the exposed portion in the non-insulated region 41a and the second non-insulated region 42a, the first region 7 was patterned. The first transparent electrode layer 28 and the first metal electrode layer 29 are formed, and the second transparent electrode layer 38 and the second metal electrode layer 39 patterned in the second region 8 are formed (electrode layer forming step: transparent electrode). Layer forming step and metal electrode layer forming step). As a result, the first electrode layer 27 and the second electrode layer 37 are formed. At this time, the first insulating layer 41 and the second insulating layer 42 are left without being removed.

In the first electrode layer 27, the metal electrode layer material film 29Z and the transparent electrode layer material film 28Z in the first non-insulating region 41a are also removed. Further, in the second electrode layer 37, the metal electrode layer material film 29Z and the transparent electrode layer material film 28Z in the second non-insulating region 42a are also removed. As a result, the above-mentioned resin film covering the metal electrode layer material film 29Z in the first non-insulating region 41a and the second non-insulating region 42a is also removed. Thereby, as in Comparative Example 1 described above, it is possible to reduce the decrease in contact property due to the resin film.

Examples of the etching solution for simultaneous etching of the metal electrode layer material film 29Z and the transparent electrode layer material film 28Z include a mixed solution of an oxidizing agent such as ammonium persulfate (ammonium persulfate) and an acidic solution such as hydrochloric acid (HCl). As a result, the surface of the first conductive semiconductor layer 25 in the first non-insulated region 41a is oxidized to form the oxide layer 25o. Further, the surface of the second conductive semiconductor layer 35 in the second non-insulating region 42a is oxidized to form the oxide layer 35o.

Next, as shown in FIG. 3E, the first contact electrode 51 is formed in the first non-insulating region 41a of the first insulating layer 41, and the second contact electrode 52 is formed in the second non-insulating region 42a of the second insulating layer 42. (Contact electrode forming step). As a result, the first contact electrode 51 includes the oxide layer 25o on the surface of the first conductive semiconductor layer 25, the side surface of the first transparent electrode layer 28, the side surface of the first metal electrode layer 29, and the side surface of the first insulating layer 41. Contact. Further, the second contact electrode 52 comes into contact with the oxide layer 35o on the surface of the second conductive semiconductor layer 35, the side surface of the second transparent electrode layer 38, the side surface of the second metal electrode layer 39, and the side surface of the second insulating layer. ..

Examples of the method for forming the first contact electrode 51 and the second contact electrode 52 include a pattern printing method such as press printing such as screen printing or gravure printing, or ejection printing such as inkjet printing. In the pattern printing method, a printing material containing Ag particles, a resin material and a solvent, that is, an Ag paste material is printed and fired (cured) to form a first contact electrode 51 and a second contact electrode 52.

As described above, by using the paste material having fluidity, the printing material can be appropriately filled in the first non-insulating region 41a and the second non-insulating region 42a. Further, by forming the first contact electrode 51 and the second contact electrode 52 after forming the first insulating layer 41 and the second insulating layer 42, the insulating layers 41 and 42 can be formed as in Comparative Example 2 described above. It is possible to reduce a decrease in the stability of the manufacturing process that is not properly formed.

After that, the optical adjustment layer 15 is formed on the entire surface of the semiconductor substrate 11 on the light receiving surface side (not shown). Through the above steps, the back electrode type solar cell 1 of the present embodiment shown in FIGS. 1, 2A and 2B can be obtained.

As described above, according to the method for manufacturing a solar cell of the present embodiment, the insulating layers 41 and 42 for ensuring insulation from the wiring members 91 and 92 are provided as metal electrode layers 29 and 39 and transparent electrode layers 28. Since it is also used as the etching resist of, 38, the steps of forming and removing the etching resist of the metal electrode layers 29 and 39 and the transparent electrode layers 28 and 38 can be reduced, and the manufacturing process of the solar cell can be simplified and the cost can be reduced. It is possible to etch.

Further, according to the method for manufacturing a solar cell of the present embodiment, after the insulating layers 41 and 42 are formed and before the contact electrodes 51 and 52 are formed, the metal electrode layers 29 and 39 and the transparent electrode layers 28 and 38 are formed. Etching. As a result, the exuded resin film in the non-insulated regions 41a and 42a can be removed, and the decrease in contact property due to the exuded resin film as in Comparative Example 1 can be reduced.

Further, according to the method for manufacturing a solar cell of the present embodiment, the contact electrodes 51 and 52 are formed after the insulating layers 41 and 42 are formed, so that the insulating layers 41 and 42 are appropriately formed as in Comparative Example 2. It is possible to reduce the decrease in stability of the manufacturing process that is not performed.

In this way, even if the manufacturing process is simplified and the cost is reduced, the deterioration of the contact property between the contact electrode and the metal electrode layer can be reduced, and the deterioration of the stability of the manufacturing process can be reduced. can.

Further, according to the method for producing a solar cell of the present embodiment, as a material for the metal electrode layers 29 and 39, a relatively inexpensive metal such as Cu (for example, Cu (for example)) is used instead of the relatively expensive known Ag paste. Wet etching is used after film formation using a PVD method such as sputtering. This makes it possible to reduce the cost of the solar cell.

(Modification example 1)
4A and 4B are cross-sectional views of the solar cell according to the first modification of the present embodiment, which is a cross-sectional view corresponding to the line IIA-IIA in FIG. As shown in FIGS. 4A and 4B, in the first non-insulating region 41a of the first insulating layer 41, the side surface of the first metal electrode layer 29 and / or the side surface of the first transparent electrode layer 28 is the first insulating layer 41. It may be less than the side of. In other words, in the first contact electrode 51, the portion of the first contact electrode 51 in contact with the side surface of the first metal electrode layer 29 and / or the side surface of the first transparent electrode layer 28 protrudes from the portion in contact with the side surface of the first insulating layer 41. May be good.

As shown in FIG. 4A, the side surface of the first transparent electrode layer 28 may be recessed from the side surface of the first metal electrode layer 29, and as shown in FIG. 4B, the side surface of the first metal electrode layer 29. The side surface may be recessed from the side surface of the first transparent electrode layer 28.

Similarly, in the second non-insulated region 42a of the second insulating layer 42, the side surface of the second metal electrode layer 39 and / or the side surface of the second transparent electrode layer 38 is recessed from the side surface of the second insulating layer 42. You may. In other words, in the second contact electrode 52, the portion of the second contact electrode 52 in contact with the side surface of the second metal electrode layer 39 and / or the side surface of the second transparent electrode layer 38 protrudes more than the portion in contact with the side surface of the second insulating layer 42. May be good.

Similarly, the side surface of the second transparent electrode layer 38 may be recessed from the side surface of the second metal electrode layer 39, and the side surface of the second metal electrode layer 39 may be smaller than the side surface of the second transparent electrode layer 38. May also decline.

According to this, due to the anchor effect, the reliability of contact between the first contact electrode 51 and the side surface of the first metal electrode layer 29 and / or the side surface of the first transparent electrode layer 28, and the second contact electrode 52 The reliability of contactability with the side surface of the second metal electrode layer 39 and / or the side surface of the second transparent electrode layer 38 can be improved.

(Modification 2)
FIG. 5A is an enlarged view of a first non-insulating region of the first insulating layer on the back surface side of the solar cell according to the second modification of the present embodiment. As shown in FIG. 5A, in the first non-insulating region 41a of the first insulating layer 41, the first contact electrode 51 includes a plurality of band shapes extending in the extending direction (Y direction) of the first region 7. The first transparent electrode layer 28, the first metal electrode layer 29, and the first insulating layer 41 may be present in a portion other than the plurality of strip shapes.

Similarly, in the second non-insulating region 42a of the second insulating layer 42, the second contact electrode 52 may include a plurality of band shapes extending in the extending direction (Y direction) of the second region 8. , The second transparent electrode layer 38, the second metal electrode layer 39, and the second insulating layer 42 may be present in a portion other than the plurality of strip shapes.

As a result, in the first non-insulated region 41a, the total length of the side surface of the first metal electrode layer 29 and the total length of the side surface of the first transparent electrode layer 28 are longer than the peripheral length of the first non-insulated region 41a. As a result, the contact area between the first contact electrode 51 and the side surface of the first metal electrode layer 29 and the side surface of the first transparent electrode layer 28 can be increased, and the contact area between the first contact electrode 51 and the first metal electrode layer 29 can be increased. The contact property with the side surface and the side surface of the first transparent electrode layer 28 can be further improved.

Further, in the first non-insulated region 41a, the first contact electrode 51 extends continuously in the extending direction (Y direction) of the first region 7, and also includes the first transparent electrode layer 28 and the first transparent electrode layer 28. The metal electrode layer 29 also extends continuously in the extending direction (Y direction) of the first region 7. Thereby, the line resistance of the first transparent electrode layer 28, the first metal electrode layer 29, and the first contact electrode 51 in the Y direction can be reduced.

Similarly, in the second non-insulated region 42a, the total length of the side surface of the second metal electrode layer 39 and the total length of the side surface of the second transparent electrode layer 38 are longer than the peripheral length of the second non-insulated region 42a. As a result, the contact area between the second contact electrode 52 and the side surface of the second metal electrode layer 39 and the side surface of the second transparent electrode layer 38 can be increased, and the contact area between the second contact electrode 52 and the second metal electrode layer 39 can be increased. The contact property with the side surface and the side surface of the second transparent electrode layer 38 can be further improved.

Similarly, in the second non-insulated region 42a, the second contact electrode 52 extends continuously in the extending direction (Y direction) of the second region 8, and the second transparent electrode layer 38 also extends. The second metal electrode layer 39 also extends continuously in the extending direction (Y direction) of the second region 8. As a result, it is possible to reduce the line resistance of the second transparent electrode layer 38, the second metal electrode layer 39, and the second contact electrode 52 in the Y direction as a whole.

(Modification example 3)
FIG. 5B is an enlarged view of the first non-insulated region of the first insulating layer on the back surface side of the solar cell according to the third modification of the present embodiment. As shown in FIG. 5B, in the first non-insulating region 41a of the first insulating layer 41, the first contact electrode 51 includes a plurality of strips extending radially on the surface (XY plane) of the first region 7. The first transparent electrode layer 28, the first metal electrode layer 29, and the first insulating layer 41 may be present in a portion other than the plurality of strip shapes.

Similarly, in the second non-insulating region 42a of the second insulating layer 42, the second contact electrode 52 may include a plurality of strips extending radially on the surface (XY plane) of the second region 8. , The second transparent electrode layer 38, the second metal electrode layer 39, and the second insulating layer 42 may be present in a portion other than the plurality of strip shapes.

As a result, in the first non-insulated region 41a, the total length of the side surface of the first metal electrode layer 29 and the total length of the side surface of the first transparent electrode layer 28 are longer than the peripheral length of the first non-insulated region 41a. As a result, the contact area between the first contact electrode 51 and the side surface of the first metal electrode layer 29 and the side surface of the first transparent electrode layer 28 can be increased, and the contact area between the first contact electrode 51 and the first metal electrode layer 29 can be increased. The contact property with the side surface and the side surface of the first transparent electrode layer 28 can be further improved.

Further, similarly to the above, it is possible to reduce the line resistance of the first transparent electrode layer 28, the first metal electrode layer 29, and the first contact electrode 51 in the Y direction as a whole.

Similarly, in the second non-insulated region 42a, the total length of the side surface of the second metal electrode layer 39 and the total length of the side surface of the second transparent electrode layer 38 are longer than the peripheral length of the second non-insulated region 42a. As a result, the contact area between the second contact electrode 52 and the side surface of the second metal electrode layer 39 and the side surface of the second transparent electrode layer 38 can be increased, and the contact area between the second contact electrode 52 and the second metal electrode layer 39 can be increased. The contact property with the side surface and the side surface of the second transparent electrode layer 38 can be further improved.

Further, similarly to the above, it is possible to reduce the line resistance of the second transparent electrode layer 38, the second metal electrode layer 39, and the second contact electrode 52 as a whole in the Y direction.

(Modification example 4)
FIG. 5C is an enlarged view of the first non-insulated region of the first insulating layer on the back surface side of the solar cell according to the fourth modification of the present embodiment. As shown in FIG. 5C, in the first non-insulating region 41a of the first insulating layer 41, the first contact electrode 51 has a plurality of band shapes extending in a grid pattern on the surface (XY plane) of the first region 7. The first transparent electrode layer 28, the first metal electrode layer 29, and the first insulating layer 41 may be present in a portion other than the plurality of strip shapes.

Similarly, in the second non-insulating region 42a of the second insulating layer 42, the second contact electrode 52 may include a plurality of strips extending in a grid pattern on the surface (XY plane) of the second region 8. Often, the second transparent electrode layer 38, the second metal electrode layer 39, and the second insulating layer 42 may be present in a portion other than the plurality of strip shapes.

As a result, in the first non-insulated region 41a, the total length of the side surface of the first metal electrode layer 29 and the total length of the side surface of the first transparent electrode layer 28 are longer than the peripheral length of the first non-insulated region 41a. As a result, the contact area between the first contact electrode 51 and the side surface of the first metal electrode layer 29 and the side surface of the first transparent electrode layer 28 can be increased, and the contact area between the first contact electrode 51 and the first metal electrode layer 29 can be increased. The contact property with the side surface and the side surface of the first transparent electrode layer 28 can be further improved.

Further, similarly to the above, it is possible to reduce the line resistance of the first transparent electrode layer 28, the first metal electrode layer 29, and the first contact electrode 51 in the Y direction as a whole.

Similarly, in the second non-insulated region 42a, the total length of the side surface of the second metal electrode layer 39 and the total length of the side surface of the second transparent electrode layer 38 are longer than the peripheral length of the second non-insulated region 42a. As a result, the contact area between the second contact electrode 52 and the side surface of the second metal electrode layer 39 and the side surface of the second transparent electrode layer 38 can be increased, and the contact area between the second contact electrode 52 and the second metal electrode layer 39 can be increased. The contact property with the side surface and the side surface of the second transparent electrode layer 38 can be further improved.

Further, similarly to the above, it is possible to reduce the line resistance of the second transparent electrode layer 38, the second metal electrode layer 39, and the second contact electrode 52 as a whole in the Y direction.

(Modification 5)
FIG. 5D is an enlarged view of the first non-insulating region of the first insulating layer on the back surface side of the solar cell according to the modified example 5 of the present embodiment. As shown in FIG. 5D, in the first non-insulating region 41a of the first insulating layer 41, the first contact electrode 51 may have a plurality of island shapes in the sea-island structure, and the first transparent electrode layer 28, the first. The metal electrode layer 29 and the first insulating layer 41 may exist in a sea shape in the sea island structure.

Similarly, in the second non-insulated region 42a of the second insulating layer 42, the second contact electrode 52 may have a plurality of island shapes in the sea-island structure, and the second transparent electrode layer 38 and the second metal electrode layer 39. And the second insulating layer 42 may exist in the sea shape in the sea island structure.

As a result, in the first non-insulated region 41a, the total length of the side surface of the first metal electrode layer 29 and the total length of the side surface of the first transparent electrode layer 28 are longer than the peripheral length of the first non-insulated region 41a. As a result, the contact area between the first contact electrode 51 and the side surface of the first metal electrode layer 29 and the side surface of the first transparent electrode layer 28 can be increased, and the contact area between the first contact electrode 51 and the first metal electrode layer 29 can be increased. The contact property with the side surface and the side surface of the first transparent electrode layer 28 can be further improved.

Further, similarly to the above, it is possible to reduce the line resistance of the first transparent electrode layer 28, the first metal electrode layer 29, and the first contact electrode 51 in the Y direction as a whole. In addition, the contact points between the first contact electrode 51 and the side surface of the first metal electrode layer 29 and the side surface of the first transparent electrode layer 28 are dispersed, so that a part of the contact points are dispersed in the reliability test in a high temperature and high humidity environment. Even when a contact failure occurs at a contact point, an increase in overall resistance can be suppressed, and reliability can be improved.

Similarly, in the second non-insulated region 42a, the total length of the side surface of the second metal electrode layer 39 and the total length of the side surface of the second transparent electrode layer 38 are longer than the peripheral length of the second non-insulated region 42a. As a result, the contact area between the second contact electrode 52 and the side surface of the second metal electrode layer 39 and the side surface of the second transparent electrode layer 38 can be increased, and the contact area between the second contact electrode 52 and the second metal electrode layer 39 can be increased. The contact property with the side surface and the side surface of the second transparent electrode layer 38 can be further improved.

Further, similarly to the above, it is possible to reduce the line resistance of the second transparent electrode layer 38, the second metal electrode layer 39, and the second contact electrode 52 as a whole in the Y direction. In addition, the contact points between the second contact electrode 52 and the side surface of the second metal electrode layer 39 and the side surface of the second transparent electrode layer 38 are dispersed, so that a part of the contact points are dispersed in the reliability test in a high temperature and high humidity environment. Even when a contact failure occurs at a contact point, an increase in overall resistance can be suppressed, and reliability can be improved.

(Modification 6)
FIG. 5E is an enlarged view of the first non-insulated region of the first insulating layer on the back surface side of the solar cell according to the modified example 6 of the present embodiment. As shown in FIG. 5E, in the first non-insulating region 41a of the first insulating layer 41, the first contact electrode 51 may have a plurality of sea shapes in the sea-island structure, and the first transparent electrode layer 28, the first. The metal electrode layer 29 and the first insulating layer 41 may exist in an island shape in the sea-island structure.

Similarly, in the second non-insulated region 42a of the second insulating layer 42, the second contact electrode 52 may include a plurality of sea shapes in the sea island structure, and the second transparent electrode layer 38 and the second metal electrode layer. The 39 and the second insulating layer 42 may be present in an island shape in the sea-island structure.

As a result, in the first non-insulated region 41a, the total length of the side surface of the first metal electrode layer 29 and the total length of the side surface of the first transparent electrode layer 28 are longer than the peripheral length of the first non-insulated region 41a. As a result, the contact area between the first contact electrode 51 and the side surface of the first metal electrode layer 29 and the side surface of the first transparent electrode layer 28 can be increased, and the contact area between the first contact electrode 51 and the first metal electrode layer 29 can be increased. The contact property with the side surface and the side surface of the first transparent electrode layer 28 can be further improved.

Further, similarly to the above, it is possible to reduce the line resistance of the first transparent electrode layer 28, the first metal electrode layer 29, and the first contact electrode 51 in the Y direction as a whole. In addition, the contact points between the first contact electrode 51 and the side surface of the first metal electrode layer 29 and the side surface of the first transparent electrode layer 28 are dispersed, so that a part of the contact points are dispersed in the reliability test in a high temperature and high humidity environment. Even when a contact failure occurs at a contact point, an increase in overall resistance can be suppressed, and reliability can be improved.

Similarly, in the second non-insulated region 42a, the total length of the side surface of the second metal electrode layer 39 and the total length of the side surface of the second transparent electrode layer 38 are longer than the peripheral length of the second non-insulated region 42a. As a result, the contact area between the second contact electrode 52 and the side surface of the second metal electrode layer 39 and the side surface of the second transparent electrode layer 38 can be increased, and the contact area between the second contact electrode 52 and the second metal electrode layer 39 can be increased. The contact property with the side surface and the side surface of the second transparent electrode layer 38 can be further improved.

Further, similarly to the above, it is possible to reduce the line resistance of the second transparent electrode layer 38, the second metal electrode layer 39, and the second contact electrode 52 as a whole in the Y direction. In addition, the contact points between the second contact electrode 52 and the side surface of the second metal electrode layer 39 and the side surface of the second transparent electrode layer 38 are dispersed, so that a part of the contact points are dispersed in the reliability test in a high temperature and high humidity environment. Even when a contact failure occurs at a contact point, an increase in overall resistance can be suppressed, and reliability can be improved.

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 modifications can be made. For example, in the above-described embodiment, the solar cell 1 using the crystalline silicon material has been exemplified, but the present invention is not limited thereto. For example, as the material of the solar cell, various materials such as gallium arsenide (GaAs) may be used.

Further, in the above-described embodiment, the heterojunction type solar cell 1 is exemplified as shown in FIG. However, the present invention is not limited to this, and can be applied to various solar cells such as homozygous solar cells.

1,1X solar cell 7 1st region 8 2nd region 11 Semiconductor substrate 13, 23, 33 Passion layer 15 Optical adjustment layer 25 1st conductive semiconductor layer 27, 27X 1st electrode layer 28, 28X 1st transparent electrode layer 28Z Transparent electrode layer Material film 29,29X First metal electrode layer 29Z Metal electrode layer Material film 35 Second conductive semiconductor layer 37,37X Second electrode layer 38,38X Second transparent electrode layer 39,39X Second metal electrode layer 41 , 41X 1st insulating layer 41Z resin film 41a 1st non-insulated area 42, 42X 2nd insulating layer 42a 2nd non-insulating area 51, 51X 1st contact electrode 52, 52X 2nd contact electrode 91 1st wiring member 92 2nd Wiring member X1 1st straight line X2 2nd straight line

Claims (10)

A semiconductor substrate, a first conductive semiconductor layer, a first transparent electrode layer, and a first metal electrode layer laminated in order on a first region that is a part of one main surface side of the semiconductor substrate, and the semiconductor substrate. On the other hand, it is a back electrode type solar cell provided with a second conductive semiconductor layer, a second transparent electrode layer and a second metal electrode layer which are sequentially laminated in a second region which is another part on the main surface side.
A first insulating layer formed in the first region so as to cover the first metal electrode layer as a whole except for the first non-insulating region.
A second insulating layer formed in the second region so as to cover the second metal electrode layer as a whole except for the second non-insulating region.
The first contact electrode formed in the first non-insulated region and
The second contact electrode formed in the second non-insulated region and
With
The first transparent electrode layer and the first metal electrode layer are not formed in the first non-insulating region, and the first transparent electrode layer and the first metal electrode layer are not formed.
The second transparent electrode layer and the second metal electrode layer are not formed in the second non-insulating region, and the second transparent electrode layer and the second metal electrode layer are not formed.
The first contact electrode is in contact with the side surface of the first transparent electrode layer, the side surface of the first metal electrode layer, and the side surface of the first insulating layer.
The second contact electrode is in contact with the side surface of the second transparent electrode layer, the side surface of the second metal electrode layer, and the side surface of the second insulating layer.
Solar cell. In the first non-insulating region, the side surface of the first metal electrode layer or the side surface of the first transparent electrode layer is recessed from the side surface of the first insulating layer.
In the second non-insulating region, the side surface of the second metal electrode layer or the side surface of the second transparent electrode layer is recessed from the side surface of the second insulating layer.
The solar cell according to claim 1. In the first non-insulated region, the surface of the first conductive semiconductor layer is oxidized.
In the second non-insulated region, the surface of the second conductive semiconductor layer is oxidized.
The first contact electrode is in contact with an oxide layer on the surface of the first conductive semiconductor layer.
The second contact electrode is in contact with an oxide layer on the surface of the second conductive semiconductor layer.
The solar cell according to claim 1 or 2. In the first non-insulated region, the total length of the side surface of the first metal electrode layer and the total length of the side surface of the first transparent electrode layer are longer than the peripheral length of the first non-insulated region.
In the second non-insulated region, the total length of the side surface of the second metal electrode layer and the total length of the side surface of the second transparent electrode layer are longer than the peripheral length of the second non-insulated region.
The solar cell according to any one of claims 1 to 3. In the first non-insulated region
The first contact electrode includes a plurality of band shapes extending in the extending direction of the first region.
The first transparent electrode layer, the first metal electrode layer, and the first insulating layer are present in a portion other than the plurality of strip shapes.
In the second non-insulated region
The second contact electrode includes a plurality of band shapes extending in the extending direction of the second region.
The second transparent electrode layer, the second metal electrode layer, and the second insulating layer are present in a portion other than the plurality of strip shapes.
The solar cell according to claim 4. In the first non-insulated region
The first contact electrode includes a plurality of strips extending radially on the surface of the first region.
The first transparent electrode layer, the first metal electrode layer, and the first insulating layer are present in a portion other than the plurality of strip shapes.
In the second non-insulated region
The second contact electrode comprises a plurality of strips extending radially in the plane of the second region.
The second transparent electrode layer, the second metal electrode layer, and the second insulating layer are present in a portion other than the plurality of strip shapes.
The solar cell according to claim 4. In the first non-insulated region
The first contact electrode includes a plurality of band shapes extending in a grid pattern on the surface of the first region.
The first transparent electrode layer, the first metal electrode layer, and the first insulating layer are present in a portion other than the plurality of strip shapes.
In the second non-insulated region
The second contact electrode includes a plurality of band shapes extending in a grid pattern on the surface of the second region.
The second transparent electrode layer, the second metal electrode layer, and the second insulating layer are present in a portion other than the plurality of strip shapes.
The solar cell according to claim 4. In the first non-insulated region
The first contact electrode has a plurality of island shapes in the sea island structure, and has a plurality of island shapes.
The first transparent electrode layer, the first metal electrode layer, and the first insulating layer exist in a sea shape in the sea island structure.
In the second non-insulated region
The second contact electrode has a plurality of island shapes in the sea island structure, and has a plurality of island shapes.
The second transparent electrode layer, the second metal electrode layer, and the second insulating layer exist in a sea shape in the sea island structure.
The solar cell according to claim 4. In the first non-insulated region
The first contact electrode has a sea shape in a sea island structure.
The first transparent electrode layer, the first metal electrode layer, and the first insulating layer exist in a plurality of island shapes in the sea island structure.
In the second non-insulated region
The second contact electrode has a sea shape in a sea island structure.
The second transparent electrode layer, the second metal electrode layer, and the second insulating layer exist in a plurality of island shapes in the sea island structure.
The solar cell according to claim 4. A semiconductor substrate, a first conductive semiconductor layer, a first transparent electrode layer, and a first metal electrode layer laminated in order on a first region that is a part of one main surface side of the semiconductor substrate, and the semiconductor substrate. On the other hand, it is a method for manufacturing a back electrode type solar cell including a second conductive semiconductor layer, a second transparent electrode layer and a second metal electrode layer which are sequentially laminated in a second region which is another part on the main surface side. hand,
A transparent electrode layer material film forming step of forming a series of transparent electrode layer material films on the first conductive type semiconductor layer and the second conductive type semiconductor layer on the one main surface side of the semiconductor substrate.
A metal electrode layer material film forming step of forming a series of metal electrode layer material films on the transparent electrode layer material film, and
The first insulating layer that covers the metal electrode layer material film in the first region as a whole except for the first non-insulating region, and the metal electrode layer material film in the second region excluding the second non-insulating region. A second insulating layer that covers the entire surface, and an insulating layer forming step that forms the first insulating layer and the second insulating layer that are separated from each other.
Using an etching method using the first insulating layer and the second insulating layer as masks, between the first insulating layer and the second insulating layer, and the first non-insulated region and the second non-insulated region. The first transparent electrode layer and the first transparent electrode layer patterned in the first region by removing the exposed portion of the metal electrode layer material film and the transparent electrode layer material film corresponding to the exposed portion in the region. A metal electrode layer is formed, the second transparent electrode layer and the second metal electrode layer patterned in the second region are formed, and the first insulating layer and the second insulating layer are left unremoved. The process of forming the transparent electrode layer and the metal electrode layer,
A first contact electrode is formed in the first non-insulated region so as to be in contact with the side surface of the first transparent electrode layer, the side surface of the first metal electrode layer, and the side surface of the first insulating layer, and the second non-insulated region is formed. A contact electrode forming step of forming a second contact electrode in the region so as to be in contact with the side surface of the second transparent electrode layer, the side surface of the second metal electrode layer, and the side surface of the second insulating layer.
including,
How to manufacture solar cells.

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