WO2020152951A1 - Substrate tray for manufacturing solar battery and method for manufacturing solar battery - Google Patents

Abstract

A tray 100 for manufacturing a solar battery is for mounting a substrate 200 so as to transport the substrate 200 to a film forming chamber in a film forming process for manufacturing a solar battery, the tray 100 including a recessed portion 120 that opens on the surface on which the substrate 200 is mounted and a resin member 130 that is disposed on a bottom face 124 of the recessed portion 120, the substrate 200 being mounted on the resin member 130.

Description

Substrate tray for manufacturing solar cell and method for manufacturing solar cell

The present disclosure relates to a substrate tray for manufacturing a solar cell and a method for manufacturing a solar cell.

In solar cells, electricity is generated by extracting carriers (electrons and holes) generated by light irradiation to the photoelectric conversion part composed of a semiconductor laminate into an external circuit through transparent electrode layers formed on both sides of the semiconductor laminate. To do. Therefore, how to form the semiconductor laminated body and the transparent electrode layer of the solar cell without deterioration of characteristics is important in the manufacturing process of the solar cell.

The semiconductor laminated body is formed by laminating a silicon-based thin film on a semiconductor substrate of crystalline silicon, for example. Film formation of a silicon-based thin film and film formation of a transparent electrode layer on a semiconductor substrate are generally performed using a chemical vapor deposition (CVD) method or a physical vapor deposition (PVD) method. In CVD or PVD, a semiconductor substrate placed on a substrate tray is transferred into a vacuum film forming chamber to perform film formation (for example, Patent Document 1).

Japanese Patent Laid-Open No. 9-115840

By the way, at the time of film formation, the semiconductor substrate and the substrate tray rub against each other, resulting in defects such as scratches and chips on the semiconductor substrate, or peeling off of the silicon-based thin film and the transparent electrode layer formed on the semiconductor substrate. Yield is reduced.

An object of the present disclosure is to suppress rubbing between a semiconductor substrate and a substrate tray in CVD or PVD, suppress generation of defects and peeling of a thin film, and improve the yield of solar cells.

A substrate tray for manufacturing a solar cell according to the present disclosure is a substrate tray on which a semiconductor substrate is placed in order to convey a semiconductor substrate to a film forming chamber in a film forming process for manufacturing a solar cell, The semiconductor substrate is provided on the resin member, and the semiconductor substrate is provided with a recess opening on a surface on which the semiconductor substrate is mounted, and a resin member disposed on at least one of a bottom surface of the recess and an outer peripheral portion of the recess. Placed on.

A method for manufacturing a solar cell according to the present disclosure is a method for manufacturing a solar cell including a film forming process for forming a thin film on a semiconductor substrate, wherein the film forming process conveys the semiconductor substrate to a film forming chamber. And a mounting step of mounting the semiconductor substrate on the substrate tray. The substrate tray has an opening on a surface on which the semiconductor substrate is mounted. The semiconductor substrate is mounted on the resin member in the mounting step, including a recess and a resin member disposed on at least one of a bottom surface of the recess and an outer peripheral portion of the recess.

According to the present disclosure, in the film forming process, direct contact between the semiconductor substrate and the substrate tray is suppressed, and thus rubbing between the both is suppressed. This suppresses the occurrence of defects and peeling of the thin film, thus improving the yield of solar cells.

FIG. 3 is a diagram for explaining the method for manufacturing the solar cell according to the first embodiment. 6 is a flow for explaining the method for manufacturing the solar cell according to the first embodiment. FIG. 3 is a perspective view of the tray according to the first exemplary embodiment. FIG. 4 is an enlarged plan view of A in FIG. 3. FIG. 5 is a sectional view taken along the line BB of FIG. 4. FIG. 6 is a view corresponding to FIG. 4 of the tray according to the second exemplary embodiment. FIG. 7 is a sectional view taken along line CC of FIG. 6. It is a FIG. 4 equivalent view of the tray which concerns on Embodiment 3. FIG. It is a FIG. 4 equivalent view of the tray which concerns on Embodiment 4. FIG. It is a FIG. 4 equivalent view of the tray which concerns on Embodiment 5. FIG. FIG. 11 is a sectional view taken along the line DD of FIG. 10. It is a FIG. 4 equivalent view of the tray which concerns on Embodiment 6. FIG. It is a FIG. 4 equivalent view of the tray which concerns on Embodiment 7. FIG.

Hereinafter, embodiments will be described in detail with reference to the drawings.

(Embodiment 1)
A solar cell manufacturing method and a solar cell manufacturing tray 100 (substrate tray) according to a first embodiment will be described with reference to FIGS. 1 to 5.

<Solar cell>
As the solar cell manufactured by the manufacturing method of the present embodiment, a heterojunction solar cell having high photoelectric conversion efficiency is preferable, and the heterojunction solar cell will be described below as an example. The heterojunction solar cell is a crystalline silicon solar cell in which a diffusion potential is formed by having a silicon thin film having a band gap different from that of single crystal silicon on the surface of a single crystal silicon substrate of one conductivity type. As the silicon-based thin film, for example, an amorphous silicon-based thin film is preferable. Among them, the one in which a thin intrinsic amorphous silicon layer is interposed between the conductive type amorphous silicon thin film for forming the diffusion potential and the single crystal silicon substrate is crystalline silicon having the highest photoelectric conversion efficiency. It is known as one of the forms of solar cells. However, the solar cell is not limited to the heterojunction solar cell, and may be, for example, a homojunction solar cell.

FIG. 1 shows an example of a method for manufacturing a solar cell according to this embodiment and a solar cell manufactured by the method.

As shown in FIG. 1, the solar cell 300 includes a semiconductor laminated body 301, a transparent electrode layer 302 formed on the main surface of the semiconductor laminated body 301, and a collector electrode 303 formed on the surface of the transparent electrode layer 302. Equipped with.

-Semiconductor stack-
The semiconductor laminated body 301 has an intrinsic silicon-based thin film 301A and a one-conductivity-type silicon-based thin film 301B that are sequentially stacked on a main surface (hereinafter, also referred to as a surface) that is a light incident surface side of the substrate 200 (semiconductor substrate). Equipped with. Further, the semiconductor laminated body 301 has a conductivity type different from that of the intrinsic silicon-based thin film 301C and the one conductivity type silicon-based thin film 301B that are sequentially stacked on the reverse main surface (hereinafter, also referred to as the back surface) of the substrate 200. And a reverse conductivity type silicon-based thin film 301D. In addition, in this specification, "one conductivity type" means one of n-type and p-type. Further, the “reverse conductivity type” means a conductivity type different from the above-mentioned “one conductivity type”. Specifically, for example, when "one conductivity type" is n-type, "reverse conductivity type" is p-type, and when "one conductivity type" is p-type, "reverse conductivity type". Is n-type. The semiconductor laminated body 301 constitutes the photoelectric conversion part of the solar cell 300. Note that, hereinafter, the intrinsic silicon-based thin film 301A, the one conductivity type silicon-based thin film 301B, the intrinsic silicon-based thin film 301C, and the opposite conductivity-type silicon-based thin film 301D are collectively referred to as "silicon-based thin films 301A, 301B, 301C, 301D" and the like. Sometimes.

-substrate-
The substrate 200 is, for example, a single conductivity type single crystal silicon substrate. Note that the n-type single crystal silicon substrate is a single crystal silicon substrate that contains atoms (for example, phosphorus) for introducing electrons into silicon atoms. Further, the p-type single crystal silicon substrate is a single crystal silicon substrate containing atoms (for example, boron) for introducing holes into silicon atoms. The substrate 200 is either an n-type or p-type single crystal silicon substrate, and particularly preferably an n-type single crystal silicon substrate.

The shape of the substrate 200 is not particularly limited, but in plan view, a square shape (hereinafter, may be referred to as “square shape”), a semi-square shape in which four corners of the square shape are cut off, a rectangular shape, It has a polygonal shape, a circular shape, or the like, and preferably has a square shape or a semi-square shape.

The size of the substrate 200 is not particularly limited, and may be changed appropriately according to the specifications of the solar cell 300. Specifically, for example, the width is 100 mm or more and 200 mm or less. In the present specification, “width” means, for example, a circle having a diameter of a circle, a polygon having a distance between two opposite sides, a rectangle having a long side, and a square having a width. The length of one side, or the length of one side when considered as a square if it is a semi-square.

The thickness of the substrate 200 is not particularly limited and is appropriately changed depending on the specifications of the solar cell 300, but is 100 μm or more and 500 μm or less, for example.

-Silicon thin film-
The silicon-based thin films 301A, 301B, 301C and 301D are, for example, amorphous silicon-based thin films. Specifically, for example, the intrinsic silicon-based thin film 301A and the intrinsic silicon-based thin film 301C are i-type hydrogenated amorphous silicon-based thin films composed of silicon and hydrogen. The one conductivity type silicon-based thin film 301B and the opposite conductivity type silicon-based thin film 301D are p-type and n-type, or n-type or p-type amorphous silicon-based thin films, respectively, preferably p-type and n-type, respectively. It is an amorphous silicon thin film.

As a method for forming the silicon-based thin films 301A, 301B, 301C, 301D, for example, a plasma CVD method is preferable.

-Transparent electrode layer-
The transparent electrode layer 302 is formed mainly of a conductive oxide. Examples of the conductive oxide include zinc oxide, indium oxide, tin oxide and the like, and these may be used alone or in combination. In particular, an indium oxide containing indium oxide as a main component is preferable from the viewpoints of conductivity, optical characteristics, and long-term reliability. In the present specification, the "main component" means that the content ratio is more than 50% by mass, preferably 70% by mass or more, and more preferably 85% by mass or more. The conductive oxide used as the main component of the transparent electrode layer contains at least one element such as Sn, W, As, Zn, Ge, Ca, Si, and C as a dopant, depending on the usage. Is preferred. Among them, indium tin oxide (ITO) using Sn as a dopant is particularly preferably used.

In FIG. 1, the transparent electrode layer 302 has a single-layer structure on each of the main surface side and the opposite main surface side, but may have a laminated structure including a plurality of layers. The method for forming the transparent electrode layer 302 is not particularly limited, but it is formed by a PVD method such as a sputtering method.

-Collection electrode-
In the heterojunction solar cell, current extraction efficiency is poor only with the transparent electrode layer, and the fill factor may decrease. Although the transparent electrode layer is mainly composed of a conductive oxide, the conductive oxide has a resistivity several orders of magnitude higher than that of metal, and the transparent electrode layer alone has a large series resistance (Rs). This is partly because it becomes too much. Therefore, in order to suppress the increase of Rs and maintain a high fill factor, a collector electrode is used in the heterojunction solar cell.

Since the collecting electrode 303 is provided on the light incident surface side of the solar cell 300, it is preferable that the collecting electrode 303 is formed in a pattern having a light-transmitting portion, such as a comb shape. This is because if the collecting electrode 303 does not have a light transmitting portion, the light blocking loss becomes large and the amount of light taken in is reduced, so that the short-circuit current is reduced. For the collecting electrode 303, it is desirable to use a material having high conductivity and chemical stability. Examples of materials that satisfy such characteristics include silver and aluminum. The collecting electrode 303 is manufactured by a known technique such as an inkjet method, a screen printing method, a conductive wire bonding method, a spray method, a vacuum deposition method, a sputtering method, a plating method, or the like.

<Method of manufacturing solar cell>
As shown in FIG. 1, in the method for manufacturing the solar cell 300 according to the present embodiment, the step S1 (film forming process) of forming the silicon-based thin films 301A, 301B, 301C and 301D and the step of forming the transparent electrode layer 302. S2 (film forming process) and step S3 of forming the collecting electrode 303 are provided.

Steps S1 and S2 are steps for forming a thin film on the substrate 200 by using the plasma CVD method, the PVD method, or the like, as described above. In this specification, these steps S1 and S2 are referred to as a film forming process.

The film forming process is performed, for example, by placing the substrate 200 on a tray, transporting it into a film forming apparatus, and forming a desired thin film on the main surface and the reverse main surface of the substrate 200.

Specifically, for example, the step S1 includes a preparation step S11, a mounting step S12, and a film forming step S13, as shown in FIG.

First, in the preparation step S11, the tray 100 is prepared as shown in FIG. The tray 100 is for transporting the substrate 200 into a film forming chamber of a plasma CVD film forming apparatus (not shown) of a depot down system. Then, the resin member 130 is arranged on the bottom surface 124 of the recess 120 of the tray 100. Next, in the mounting step S12, the substrate 200 is mounted on the surface of the resin member 130 in the recess 120 of the tray 100. Then, in the film forming step S13, the tray 100 is transported into the film forming chamber, and a film forming material is vapor-deposited from the upper side on the main surface of the substrate 200 (see an arrow P1 in FIG. 5) to form a silicon-based thin film. 301A and 301B are sequentially formed into a film. After that, the substrate 200 is taken out from the plasma CVD film forming apparatus, turned over, and further subjected to the placing step S12 and the film forming step S13, and then the silicon-based thin films 301C and 301D are sequentially formed on the reverse main surface of the substrate 200. Thus, the semiconductor laminated body 301 is obtained.

The obtained semiconductor laminated body 301 is taken out from the plasma CVD film forming apparatus, and is carried in the PVD film forming apparatus while being placed on the tray 100 or after being replaced with another tray. Then, the transparent electrode layers 302 are formed on both front and back surfaces of the semiconductor laminated body 301 (step S2). When another tray is used, a tray having the same configuration as the tray 100 used in step S1 may be used, or a tray having another configuration may be used.

Then, the semiconductor laminated body 301 having the transparent electrode layer 302 formed thereon is taken out from the PVD film forming apparatus, and the patterns of the collecting electrodes 303 are formed on both the front and back surfaces of the transparent electrode layer 302 by using the above-mentioned various methods. 300 is obtained (step S3).

<Tray>
Hereinafter, the configuration of the tray 100 according to this embodiment will be described in detail. In the following description, the tray 100 used in step S1 will be described as an example.

As shown in FIGS. 3 to 5, the tray 100 is provided with a flat plate-shaped main body 101 and a plurality of concave portions 120 having a square shape in a plan view which are opened in a surface 110 of the main body 101 on which the substrate 200 is placed. It is an insulating member. Examples of the material of the non-insulating tray 100 include metals such as titanium, aluminum, and stainless. However, the material of the tray 100 is not limited to metal, and for example, the tray may be formed of carbon material or the like. In the following description, for the sake of convenience, the side on which the substrate 200 is placed is the upper side and the opposite side is the lower side, as shown in FIG. 3, for example. Further, in FIG. 3, the tray 100 includes four recesses 120, but the number of recesses 120 is not limited to four, and may be two, three, or five or more.

The recessed portion 120 has a square-shaped opening 121 formed in the surface 110 of the tray 100 in plan view, four side walls 122 extending downward from the opening 121, and a square-shaped bottom surface connected to the lower ends of the four side walls 122. And 124. The lower ends of the four side walls 122 form the outer peripheral end 124A of the bottom surface 124.

The shape of the recess 120 is not limited to the square shape in plan view, and may be a rectangular shape, a polygonal shape, a circular shape in plan view, depending on the shape of the substrate 200 or regardless of the shape of the substrate 200. Be changed.

The size of the recess 120, that is, the width W11 of the bottom surface 124 is slightly larger than the substrate 200. That is, as will be described later in detail, since the distance between the substrate 200 and the side wall 122 of the recess 120 is sufficiently small, the substrate 200 does not move largely inside the recess 120 during transport of the tray 100, film formation, or the like. The damage to the substrate 200 and the like can be suppressed.

Note that the size of the recess 120 is not limited to the configuration, and may be appropriately changed according to the shape of the substrate 200, the specifications of the solar cell 300, and the like.

-Resin member-
Here, a tape-shaped resin member 130 is disposed on the bottom surface 124 of the recess 120.

The resin member 130 suppresses direct contact between the tray 100 and the substrate 200 when the substrate 200 is placed in the recess 120. The resin member 130 is provided at two locations (a plurality of locations) on the outer peripheral portion 124B along the outer peripheral edge 124A on the bottom surface 124 of the recess 120. The resin member 130 is preferably arranged at least at two positions on the outer peripheral portion 124B of the bottom surface 124 of the recess 120, and may be at three or more positions. Further, the shape of the resin member 130 is not limited to the tape shape, and may be another shape such as a dot shape or a block shape.

As shown in FIG. 5, the resin member 130 has a two-layer laminated structure including an adhesive layer 132 that contacts the surface of the bottom surface 124 of the tray 100 and a heat resistant resin layer 134 that is laminated on the adhesive layer 132. is there. The resin member 130 is not limited to the laminated structure of two layers, and may be a single layer or a laminated structure of three or more layers. When the resin member 130 has a laminated structure of three or more layers, it is desirable that the layer contacting the tray 100 be the adhesive layer 132 and the layer contacting the substrate 200 be the heat resistant resin layer 134.

The adhesive layer 132 is for fixing the resin member 130 to the tray 100. The main component of the adhesive layer 132 is an epoxy resin, an acrylic resin, a silicone resin, or the like, and is preferably a silicone resin from the viewpoint of plasma resistance in the film forming process.

The heat-resistant resin layer 134 is a layer that comes into contact with the substrate 200 when the substrate 200 is placed in the placing step S12, and is for suppressing contact/rubbing between the substrate 200 and the tray 100. The main component of the heat resistant resin layer 134 is a polyimide resin, a polytetrafluoroethylene (PTFE) resin, a polyolefin resin, or the like, and is preferably a polyimide resin from the viewpoint of plasma resistance in the film forming process.

The thickness of the heat resistant resin layer 134 is, for example, 30 μm or less, preferably 10 μm or more and 25 μm or less. The total thickness of the resin member 130 is, for example, 100 μm or less, preferably 80 μm or less, more preferably 15 μm or more and 50 μm or less. As a result, the diffusion of water and low molecular weight components during the film forming process is suppressed while ensuring sufficient elasticity of the resin member 130 for suppressing the rubbing between the substrate 200 and the tray 100.

The heat-resistant resin layer 134 preferably has appropriate slipperiness and anti-blocking properties from the viewpoint of ease of placing and taking out the substrate 200. Specifically, it is preferable that the heat-resistant resin layer 134 has fine irregularities on the surface from the viewpoint of improving the slip property and the anti-blocking property. Such a concavo-convex shape is formed by adding a filler such as silica to the resin material forming the heat resistant resin layer 134, or by roughening the surface. Regarding the surface roughness of the heat resistant resin layer 134, the average surface roughness (Ra) is, for example, 10 nm or more and 100 nm or less, and particularly preferably 20 nm or more and 70 nm or less. The slipperiness and anti-blocking property are expressed by the coefficient of friction between the substrate 200 and the heat resistant resin layer 134. For example, the coefficient of static friction is preferably 0.4 or more and 0.5 or less, and the coefficient of dynamic friction is It is preferably 0.3 or more and 0.4 or less.

In the mounting step S12, the substrate 200 is mounted on the resin member 130 inside the recess 120 by, for example, Bernoulli hand. At this time, as shown in FIG. 4, the substrate 200 is preferably placed on the resin member 130 so as to cover the entire resin member 130.

The plasma CVD method or PVD method of the film forming process is a plasma process in a vacuum atmosphere. By receiving radiant heat of plasma in a vacuum atmosphere, water and low molecular weight components may diffuse from the adhesive layer 132 and the heat resistant resin layer 134 into the film forming chamber. These water content and low molecular weight components cause quality deterioration and contamination of the silicon-based thin films 301A and 301B and the transparent electrode layer 302, resulting in deterioration of solar cell performance.

In the tray 100 according to the present embodiment, when the substrate 200 is placed in the placing step S12, the outer peripheral end 136 of the resin member 130 is located inside the outermost end 201 of the substrate 200 in plan view. In addition, it is preferable that the resin member 130 is arranged. In other words, preferably, when the substrate 200 is placed in the placing step S12, the resin member 130 is completely covered by the substrate 200 in plan view.

Specifically, referring to FIGS. 4 and 5, the resin member 130 is preferably arranged so as to satisfy the following expression (1).

W1≧W2 (1)
However, as shown in FIGS. 4 and 5, W1 is the shortest distance between the outer peripheral end 136 of the resin member 130 closest to the side wall 122 and the outer peripheral end 124A of the bottom surface 124 of the recess 120. W2 is the shortest distance between the side wall 122 and the outermost end 201 that is closest to the side wall 122 of the substrate 200. The shortest distance W2 is defined by the following equation (2).

W2=(W11-W12)/2 (2)
However, W11 is the width of the bottom surface 124 of the recess 120, and W12 is the width of the substrate 200.

W1 is preferably 0.1 mm or more and 45 mm or less, and more preferably 0.125 mm or more and 40 mm or less. Further, W2 is preferably 0.1 mm or more and 2 mm or less, and more preferably 0.3 mm or more and 0.9 mm or less. The shortest distance W3 between the outermost end 201 of the substrate 200 and the outer peripheral end 136 of the resin member 130 in plan view, which is represented by the following formula (3), is preferably 0 mm or more and 44.9 mm or less, and 0 It is preferably 0.05 mm or more and 39.9 mm or less.

W3=W1-W2 (3)
With the above configuration, in the film forming step S13, the influence of radiant heat on the resin member 130 due to the wraparound of plasma to the back surface side of the substrate 200 is suppressed.

Note that the preparation step S11 and the placement step S12 are performed in order to suppress contamination of the surface of the substrate 200 due to oxidants such as ozone components contained in the atmosphere and moisture, and the oxidant concentration within a predetermined range and humidity within a predetermined range. It is desirable to be done in. Specifically, the oxidant concentration is preferably 0 ppb or more and 10 ppb or less, and more preferably 0 ppb or more and 5 ppb or less. The relative humidity (RH) is preferably 40% RH or more and 70% RH or less, and more preferably 50% RH or more and 60% RH or less.

<Effect>
When the tray 100 according to the present embodiment is used in the film forming process, contact between the substrate 200 and the tray 100 and rubbing between the both are suppressed, so that generation of defects and peeling of the thin film are suppressed, and by extension, the solar cell. Yield is improved. Specifically, the yield calculated in the later-described appearance observation test is preferably 70% or more, more preferably 80% or more, and particularly preferably 90% or more.

Further, in particular, by setting the arrangement and thickness of the resin member 130 within the above range, and/or by setting the oxidant concentration and humidity in the preparation process and the placement process of the tray 100 within the above ranges, the solar cell 300 The deterioration of photoelectric conversion characteristics is suppressed, and the long-term reliability of the solar cell 300 is improved. Specifically, Voc calculated in the photoelectric conversion characteristic test described below is preferably 0.6 V or higher, more preferably 0.7 V or higher, and particularly preferably 0.7 V or higher and 0.8 V or lower. The fill factor (FF) is preferably 0.55 or more, more preferably 0.6 or more, and particularly preferably 0.7 or more and 0.85 or less.

(Embodiment 2)
Hereinafter, other embodiments will be described in detail. In the description of these embodiments, the same parts as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIGS. 6 and 7, a through hole 126 may be provided in the central portion 124C of the bottom surface 124 of the recess 120. In this case, the substrate 200 is placed on the resin member 130 arranged on the bottom surface 124 with its main surface facing downward. Then, a film forming material is vapor-deposited from the lower side through the through holes 126 (see the arrow P2 in FIG. 7) to form the silicon-based thin films 301A and 301B and the transparent electrode layer 302 on the main surface of the substrate 200. The tray 100 according to this embodiment is suitably used for a deposition-type film forming apparatus. The size of the through hole 126 is not particularly limited and is appropriately determined according to the specifications of the solar cell 300 and the film forming apparatus, but the width W21 is 98 mm or more and 198 mm or less, for example.

(Embodiment 3)
As shown in FIG. 8, in the tray 100 according to the first embodiment, the resin member 130 may be arranged not only on the outer peripheral portion 124B of the bottom surface 124 but also on the central portion 124C of the bottom surface 124. As a result, contact and rubbing between the tray 100 and the substrate 200 are effectively suppressed.

(Embodiment 4)
As shown in FIG. 9, in the tray 100 according to the first embodiment, the resin member 130 may be arranged over the entire circumference of the outer peripheral portion 124B of the bottom surface 124. As a result, contact and rubbing between the tray 100 and the substrate 200 are effectively suppressed.

(Embodiment 5)
As shown in FIGS. 10 and 11, the width W11 of the recess 120 may be smaller than the width W12 of the substrate 200. In this case, the resin member 130 is arranged at two positions (a plurality of positions) of the opening 121 of the recess 120. 10 and 11, the resin member 130 is arranged from the outer peripheral portion 121A of the opening 121 to the side wall 122 and the outer peripheral portion 124B of the bottom surface 124. The resin member 130 is preferably arranged in at least two places of the opening 121 of the recess 120, and may be arranged in three or more places. Further, the resin member 130 may be disposed at least on the outer peripheral portion 121A of the opening 121, and may not be disposed on the outer peripheral portion 124B of the side wall 122 and the bottom surface 124.

The substrate 200 is placed so as to cover the entire recess 120 in a plan view, as shown in FIG. Then, it is particularly preferable that the resin member 130 is placed so as to cover the whole. In other words, it is preferable that the resin member 130 be arranged such that the outer peripheral end 136 of the resin member 130 is located inside the outermost end 201 of the substrate 200 in a plan view when the substrate 200 is placed. ..

Specifically, the resin member 130 is preferably arranged so as to satisfy the following formula (4).

W52≧W51 (4)
However, as shown in FIGS. 10 and 11, W51 is the shortest distance between the outer peripheral end 136 of the resin member 130 arranged on the outer peripheral portion 121A of the opening 121 of the tray 100 and the opening 121. W52 is the shortest distance between the outermost end 201 of the substrate 200 and the opening 121 in a plan view. The shortest distance W52 is defined by the following equation (5).

W52=(W12-W11)/2 (5)
However, W11 is the width of the bottom surface 124 of the recess 120, and W12 is the width of the substrate 200.

W51 is preferably 1 mm or more and 5 mm or less, and more preferably 2 mm or more and 4 mm or less. Further, W52 is preferably 1 mm or more and 8 mm or less, and more preferably 1.5 mm or more and 6 mm or less. Then, the shortest distance W53 in plan view between the outermost end 201 of the substrate 200 and the outer peripheral end 136 of the resin member 130, which is represented by the following formula (6), is preferably 0 mm or more and 3 mm or less, and 0.05 mm. More preferably, it is 2.5 mm or less.

W53=W52-W51 (3)
With the above configuration, in the film forming process, the influence of radiant heat on the resin member 130 due to the wraparound of plasma to the back surface side of the substrate 200 is suppressed.

According to the tray 100 according to the present embodiment, the substrate 200 is smaller than the concave portion 120, so that when the substrate 200 is deformed by the radiant heat of plasma in the film forming process, the central portion of the substrate 200 contacts the tray 100. The occurrence of defects and the deterioration of the quality of the thin film are suppressed.

(Embodiment 6)
As shown in FIG. 12, in the tray 100 according to the fifth embodiment, the resin member 130 may be arranged over the entire circumference of the opening 121 of the recess 120. As a result, contact and rubbing between the tray 100 and the substrate 200 are effectively suppressed.

(Embodiment 7)
As shown in FIG. 13, in the tray 100 according to the fifth embodiment, the recess 120 may be circular. In this case, the shortest distance W73 between the outer peripheral end 136 of the resin member 130 and the outermost end 201 of the substrate 200 is preferably 0 mm or more and 3 mm or less, and more preferably 0.05 mm or more and 2.5 mm or less.

(Other embodiments)
The substrate 200 may have a textured structure on the front surface and/or the back surface. As a result, the semiconductor laminated body 301 formed using the substrate 200 as a base body also has a texture structure, so that the incident light is confined in the semiconductor laminated body 301 serving as the photoelectric conversion unit, and the power generation efficiency of the solar cell 300 is improved. .. The texture structure is formed, for example, by performing an etching process or the like on the front surface and/or the back surface of the substrate 200.

For example, in the first embodiment and the like, a mask (not shown) may be installed above the substrate 200 in the film forming process. The mask is for suppressing the film forming material from wrapping around to the surface of the substrate 200 opposite to the surface on which the silicon-based thin films 301A and 301B and the transparent electrode layer 302 are formed. The mask is installed so as to cover the peripheral portion of the substrate 200, for example. In this case, the resin member 130 is arranged so as to be located inside the outer peripheral portion of the mask in plan view. In other words, the resin member 130 is completely covered with the substrate 200 and the mask in a plan view.

The silicon-based thin films 301A and 301B, the transparent electrode layer 302, and the collector electrode 303 may be formed on both surfaces of the substrate 200. In this case, for example, each of the steps S1 to S3 may be performed on the front surface of the substrate 200 and turned over to the back surface of the substrate 200.

Next, we will explain the concrete examples.

<Solar cell sample preparation>
The solar cell samples of Examples 1 to 7 and Comparative Example 1 shown in Table 1 were prepared by the following procedure.

(Example 1)
As the substrate 200, an n-type single crystal silicon wafer having a plane of incidence of (100) and a thickness of 200 μm was cut into a semi-square shape having a width W12 of 156.75 mm. This wafer was immersed in a 2% by mass HF aqueous solution for 3 minutes to remove the silicon oxide film on the surface, and then rinsed with ultrapure water twice. This silicon wafer was immersed in a mixed aqueous solution of 5% by mass KOH/15% by mass isopropyl alcohol held at 70° C. for 15 minutes to etch the surface of the wafer to form a textured structure. After that, rinsing with ultrapure water was performed twice.

On the other hand, in the embodiment shown in FIGS. 3 to 5, a polyimide tape (Kapton adhesive tape manufactured by Teraoka Manufacturing Co., Ltd., as a resin member 130 is formed on the bottom surface 124 of the recess 120 of the tray 100 having the square recess 120 (width W11=157 mm). 650S#25, thickness 50 μm, polyimide layer thickness 25 μm) was attached. The shortest distance W1 from the outer peripheral edge 124A of the bottom surface 124 to the outer peripheral edge 136 of the polyimide tape was 20 mm. Further, the work of attaching the polyimide tape to the tray 100 and the work of placing the wafer were carried out in a clean room under the environment of an oxidant concentration of 8 ppb and a relative humidity of 55% RH.

Then, the above-mentioned wafer was placed on the polyimide tape in the recess 120 of the tray 100. The tray was introduced into the film forming chamber of the plasma CVD film forming apparatus, and the first i-type amorphous silicon layer as an intrinsic silicon-based thin film was formed to a film thickness of 5 nm on the surface of the wafer. The film forming conditions for the first i-type amorphous silicon layer were: substrate temperature: 150° C., pressure: 120 Pa, SiH ₄ /H ₂ flow rate ratio: 3/10, input power density: 0.011 W/cm ² . ..

Then, a p-type amorphous silicon layer having a film thickness of 7 nm was formed on the first i-type amorphous silicon layer as a reverse conductivity type silicon-based thin film. The film forming conditions of the p-type amorphous silicon layer were as follows: substrate temperature: 150° C., pressure: 60 Pa, SiH ₄ /B ₂ H ₆ flow rate ratio: 1/3, input power density: 0.01 W/cm ² . .. The B ₂ H ₆ gas flow rate described above is the flow rate of the diluent gas diluted with H ₂ to a B ₂ H ₆ concentration of 5000 ppm.

Similarly, a second i-type amorphous silicon layer is formed as an intrinsic silicon thin film on the main surface side opposite to the main surface on which the p-type amorphous silicon layer is formed, and a second i-type amorphous silicon layer. An n-type amorphous silicon layer was formed on the above. The conditions for forming the n-type silicon layer were as follows: substrate temperature: 150° C., pressure: 60 Pa, SiH ₄ /PH ₃ flow rate ratio: 1/2, input power density: 0.01 W/cm ² . The PH ₃ gas flow rate mentioned above is the flow rate of the diluent gas diluted with H ₂ to a PH ₃ concentration of 5%.

The semiconductor laminated body 301 manufactured as described above was taken out from the plasma CVD film forming apparatus, placed in the separately prepared recess 120 of the tray 100 having the same structure, and carried into the sputtering apparatus as the PVD film forming apparatus. Then, ITO was formed into a film having a thickness of 100 nm as a transparent electrode layer on the p-type amorphous silicon layer and the n-type amorphous silicon layer of the semiconductor laminated body 301 by the sputtering method. The ITO was formed by using indium tin oxide as a target and applying a power density of 0.5 W/cm ^{2 in} an atmosphere of argon and oxygen at a substrate temperature of room temperature and a pressure of 0.2 Pa.

Next, the substrate was taken out from the sputtering device, and a comb-shaped collector electrode was formed with silver paste on the transparent electrode layer of the photoelectric conversion part thus produced using a screen printing method.

Then, the semiconductor laminated body with electrodes manufactured as described above was annealed at 180° C. for 1 hour to obtain a solar cell sample.

(Example 2)
A solar cell sample was produced in the same manner as in Example 1 except that the shortest distance W1 from the outer peripheral edge 124A of the bottom surface 124 of the recess 120 of the tray 100 to the outer peripheral edge 136 of the polyimide tape was 40 mm.

(Example 3)
A solar cell sample was produced in the same manner as in Example 1 except that the shortest distance W1 from the outer peripheral edge 124A of the bottom surface 124 of the recess 120 of the tray 100 to the outer peripheral edge 136 of the polyimide tape was 0.125 mm.

(Example 4)
A solar cell sample was produced in the same manner as in Example 1 except that the shortest distance W1 from the outer peripheral edge 124A of the bottom surface 124 of the recess 120 of the tray 100 to the outer peripheral edge 136 of the polyimide tape was 0 mm.

(Example 5)
A solar cell sample was prepared in the same manner as in Example 1 except that a polyimide tape (Kapton adhesive tape 650S#25, thickness 100 μm, polyimide layer thickness 25 μm, manufactured by Teraoka Seisakusho Co., Ltd.) was attached as the resin member 130.

(Example 6)
A solar cell sample was produced in the same manner as in Example 1 except that a PTFE tape (ASF-110FR, thickness: 80 μm, PTFE layer thickness: 23 μm, manufactured by Chukoh Chemical Industries, Ltd.) was attached as the resin member 130.

(Example 7)
A solar cell sample was produced in the same manner as in Example 1 except that the tray 100 was stored and the polyimide tape was attached under the environment of an oxidant concentration of 15 ppb and a relative humidity of 90% RH.

(Comparative Example 1)
A solar cell sample was produced in the same manner as in Example 1 except that the wafer was placed in the recess 120 without attaching the polyimide tape to the bottom surface 124 of the recess 120 of the tray 100.

<Appearance observation test>
100 solar cell samples according to each of Examples 1 to 7 and Comparative Example 1 were manufactured by the above-described procedure, and one tester visually observed the appearance of the surface. As a result of visual observation, those in which the solar cell sample was chipped and cracked were judged to be defective appearance products, and those which did not occur were judged to be excellent appearance products. The yield of the solar cell sample shown in Table 1 was calculated by expressing the percentage of the number of excellent appearance products in 100 solar cell samples as a percentage.

<Photoelectric conversion characteristic evaluation test>
With respect to the solar cell sample determined to be a good appearance product in the appearance observation test, the open circuit voltage and the short circuit as its photoelectric conversion characteristics were obtained by measuring the voltage-current characteristics under the irradiation of simulated sunlight of AM1.5 and 1 sun. The current was measured.

-The average value of open circuit voltage of good appearance products was calculated as Voc shown in Table 1.

Also, the fill factor FF shown in Table 1 was calculated from the average value of the open-circuit voltage and the average value of the short-circuit current of the excellent appearance products of each sample.

<Discussion>
The solar cell sample produced without disposing the resin member of Comparative Example 1 had a yield of 67%, while the solar cell samples produced by disposing the resin member of Examples 1 to 7 had yields of 67%. The rate was 90% or more, and it was found that the yield of the solar cell sample was improved by disposing the resin member.

In addition, comparing the photoelectric conversion characteristics in Examples 1 to 7, as compared with the solar cell sample of Example 6 using the PTFE tape, the solar cell samples of Examples 1 to 5 and 7 using the polyimide tape were compared. Is more excellent in photoelectric conversion characteristics.

In addition, in Examples 1 to 5 and Example 7, the solar cell samples of Examples 1 to 5 having low oxidant concentration and humidity have photoelectric conversion characteristics as compared with the solar cell samples of Example 7 having high oxidant concentration and humidity. Excellent in

Furthermore, in Examples 1 to 5, the solar cell samples of Examples 1 to 4 in which the thickness of the polyimide tape is 50 μm are superior to the solar cell samples of Example 5 in which the thickness of the polyimide tape is 100 μm.

Further, in Examples 1 to 4, the solar cell samples of Examples 1 to 3 satisfying W1≧W2 are superior in photoelectric conversion characteristics as compared with the solar cell sample of Example 4 in which W1<W2.

100 trays (substrate tray)
101 (Tray) Main Body 110 (Tray) Surface 120 Recess 121 121 Opening 121A (Opening) Outer Perimeter 122 Sidewall 124 Bottom Surface 124A (Bottom) Outer Edge 124B (Bottom) Outer Edge 124C (Bottom) Central 130 Resin Member 132 Adhesive Layer 134 Heat Resistant Resin Layer 200 Substrate (Semiconductor Substrate)
201 Outermost end (of substrate) 300 Solar cell 301 Semiconductor laminate 301A Intrinsic silicon-based thin film 301B One conductivity type silicon based thin film 301C Intrinsic silicon based thin film 301D Reverse conductivity type silicon based thin film 302 Transparent electrode layer 303 Collection electrode S11 Preparation step S12 Mounting step S13 Film forming step W11 (recessed portion) width W12 (substrate) width

Claims (11)

In a film forming process for manufacturing a solar cell, a substrate tray on which the semiconductor substrate is placed for transferring the semiconductor substrate to a film forming chamber,
A recess opening on the surface on which the semiconductor substrate is mounted,
A resin member disposed on at least one of the bottom surface of the recess and the outer peripheral portion of the recess,
A substrate tray for manufacturing a solar cell, wherein the semiconductor substrate is placed on the resin member. A method for manufacturing a solar cell comprising a film forming process for forming a thin film on a semiconductor substrate,
The film forming process is
A preparatory step of preparing a substrate tray for transporting the semiconductor substrate to a film forming chamber,
A mounting step of mounting the semiconductor substrate on the substrate tray,
The substrate tray is
A recess opening on the surface on which the semiconductor substrate is mounted,
A resin member disposed on at least one of the bottom surface of the recess and the outer peripheral portion of the recess,
The method of manufacturing a solar cell, wherein the semiconductor substrate is placed on the resin member in the placing step. The method for manufacturing a solar cell according to claim 2,
The method for manufacturing a solar cell, wherein in the placing step, the semiconductor substrate is placed on the resin member so as to cover the entire resin member. The method for manufacturing a solar cell according to claim 3,
The shape of the semiconductor substrate is a square shape or a semi-square shape,
The shape of the recess is a square shape having a width larger than the width of the semiconductor substrate in a plan view,
The resin member is arranged at a plurality of locations or the entire circumference of the outer peripheral portion of the bottom surface of the recess,
A method of manufacturing a solar cell, wherein, when the semiconductor substrate is placed on the resin member, an outer peripheral end of the resin member is located inside an outermost end of the semiconductor substrate. The method for manufacturing a solar cell according to claim 3,
The shape of the semiconductor substrate is a square shape or a semi-square shape,
The shape of the recess is a square shape having a width smaller than the width of the semiconductor substrate in a plan view,
The resin member is arranged at a plurality of positions or the entire circumference of the outer peripheral portion of the recess,
A method for manufacturing a solar cell, wherein, when the semiconductor substrate is placed on the resin member, an outer peripheral end of the resin member is located inside an outermost end of the semiconductor substrate. The method for manufacturing a solar cell according to claim 2,
The method for manufacturing a solar cell, wherein the resin member has a laminated structure of two or more layers. The method for manufacturing a solar cell according to claim 6,
The resin member is
An adhesive layer that contacts the surface of the substrate tray,
A method of manufacturing a solar cell, comprising: a heat-resistant resin layer in contact with the semiconductor substrate. The method for manufacturing a solar cell according to claim 7,
The solar cell manufacturing method, wherein the main component of the adhesive layer is a silicone resin. The method for manufacturing a solar cell according to claim 7,
The solar cell manufacturing method, wherein the main component of the heat resistant resin layer is polyimide. The method for manufacturing a solar cell according to claim 9,
The heat-resistant resin layer has a thickness of 10 μm or more and 25 μm or less,
The method for manufacturing a solar cell, wherein the resin member has a thickness of 15 μm or more and 50 μm or less. The method for manufacturing a solar cell according to any one of claims 2 to 10,
The preparation step and the placement step are preferably 0 ppb or more and 10 ppb or less, more preferably 0 ppb or more and 5 ppb or less oxidant concentration and preferably 40% RH or more and 70% RH or less, more preferably 50% RH or more and 60% RH or less. Of manufacturing a solar cell, which is performed at the same humidity.

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