TWI721759B - Substrate tray for solar cell manufacturing and solar cell manufacturing method - Google Patents

Abstract

The solar cell manufacturing tray (100) is used in the film-making process of manufacturing solar cells. In order to transport the substrate (200) to the film forming chamber, the substrate (200) is mounted on the tray (100). The tray (100) has a recess (120) and a resin member (130). The recess (120) is open on the surface of the tray (100) on the side where the substrate (200) is mounted, and the resin component (130) is arranged on the bottom surface (124) of the recess (120).

Description

Substrate tray for solar cell manufacturing and solar cell manufacturing method

The present invention relates to a substrate tray for manufacturing solar cells and a manufacturing method of solar cells

Carriers (electrons and holes) are generated by light irradiating the photoelectric conversion part composed of semiconductor laminates in solar cells, and the carriers (electrons and holes) are taken out to the outside through the transparent electrode layers formed on both sides of the semiconductor laminates Electric circuits, solar cells generate electricity in this way. Therefore, how to form the semiconductor laminate and the transparent electrode layer of the solar cell without reducing the performance becomes very important in the solar cell manufacturing process.

The semiconductor laminate is formed by laminating a silicon-based thin film on a crystalline silicon semiconductor substrate, for example. Silicon-based thin film formation and transparent electrode layer formation on semiconductor substrates are generally performed by chemical vapor deposition (CVD) or physical vapor deposition (PVD). In CVD or PVD, a semiconductor substrate is placed on a substrate tray and transported to a vacuum deposition chamber for film formation (for example, Patent Document 1).

【Prior Technical Literature】

【Patent Literature】

Patent Document 1: Japanese Patent Laid-Open No. 9-115840

In addition, during film formation, due to friction between the semiconductor substrate and the substrate tray, the semiconductor Defects such as scratches and defects on the substrate, or separation of the silicon-based thin film and transparent electrode layer formed on the semiconductor substrate, will reduce the yield of solar cells.

The problem to be solved by the present invention is to control the friction between the semiconductor substrate and the substrate tray in CVD or PVD, prevent the occurrence of defects and the separation of the film, and improve the yield of solar cells.

The substrate tray for solar cell manufacturing related to the present invention is to transport the semiconductor substrate to the film forming chamber during the film forming process for manufacturing solar cells, and the semiconductor substrate is mounted on the substrate tray. The substrate tray has recesses and resin. The recessed portion is opened on the surface of the substrate tray on the side where the semiconductor substrate is mounted, the resin component is arranged on at least one of the bottom surface of the recessed portion and the outer peripheral portion of the recessed portion, and the semiconductor substrate is mounted on the resin component.

The method of manufacturing a solar cell according to the present invention includes a film forming process of forming a thin film on a semiconductor substrate, the film forming process including: a preparation step of preparing a substrate tray for transporting the semiconductor substrate to the film forming chamber, and A mounting step of mounting the semiconductor substrate on the substrate tray. The substrate tray has a recessed portion and a resin component, the recessed portion is open on the surface of the substrate tray on one side where the semiconductor substrate is mounted, and the resin component is arranged on at least one of the bottom surface of the recessed portion and the outer peripheral portion of the recessed portion. In the step, the semiconductor substrate is mounted on the resin component.

Through the use of the present invention, the semiconductor substrate and the substrate tray will be prevented from directly contacting during the film forming process, thereby reducing the friction between the two. This can prevent the occurrence of defects and the detachment of the thin film, and improve the yield of solar cells.

100‧‧‧Tray (Substrate Tray)

101‧‧‧(The main body of the pallet)

110‧‧‧(The surface of the pallet)

120‧‧‧Concave

121‧‧‧Opening

121A‧‧‧(opening part) outer peripheral part

122‧‧‧Sidewall

124‧‧‧Bottom

124A‧‧‧(bottom) outer peripheral end

124B‧‧‧ (bottom) outer periphery

124C‧‧‧(Bottom) central part

130‧‧‧Resin parts

132‧‧‧Adhesive layer

134‧‧‧Heat-resistant resin layer

200‧‧‧Substrate (semiconductor substrate)

201‧‧‧(The outermost end of the substrate)

300‧‧‧Solar cell

301‧‧‧Semiconductor laminated body

301A‧‧‧Intrinsic silicon film

301B‧‧‧A conductive silicon-based film

301C‧‧‧Intrinsic silicon film

301D‧‧‧Reverse conductivity silicon-based film

302‧‧‧Transparent electrode layer

303‧‧‧ Collector

S11‧‧‧Preparation steps

S12‧‧‧Installation steps

S13‧‧‧Film making steps

W11‧‧‧(The width of the recess)

W12‧‧‧(substrate) width

Fig. 1 is a diagram for explaining the method of manufacturing the solar cell according to the first embodiment.

Fig. 2 is a flowchart for explaining the method of manufacturing the solar cell according to the first embodiment.

Fig. 3 is a perspective view of the tray according to the first embodiment.

[Fig. 4] is an enlarged top view of A in Fig. 3.

[Fig. 5] is a cross-sectional view taken along the line B-B in Fig. 4. [Fig.

Fig. 6 is a view corresponding to Fig. 4 of the tray according to the second embodiment.

[Fig. 7] is a cross-sectional view taken along the line C-C in Fig. 6.

Fig. 8 is a diagram corresponding to Fig. 4 of the tray according to the third embodiment.

Fig. 9 is a view corresponding to Fig. 4 of the tray according to the fourth embodiment.

Fig. 10 is a view corresponding to Fig. 4 of the tray according to the fifth embodiment.

Fig. 11 is a cross-sectional view taken along the line D-D of Fig. 10;

Fig. 12 is a diagram corresponding to Fig. 4 of the tray according to the sixth embodiment.

Fig. 13 is a view corresponding to Fig. 4 of the tray according to the seventh embodiment.

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

(Embodiment 1)

1 to 5, the manufacturing method of the solar cell and the solar cell manufacturing tray 100 (substrate tray) according to Embodiment 1 will be described.

(Solar battery)

The solar cell manufactured by the manufacturing method in this embodiment is preferably a heterojunction solar cell with a high photoelectric conversion efficiency. The heterojunction solar cell will be taken as an example for illustration below. Heterojunction solar cells are formed on the surface of a conductive monocrystalline silicon substrate to form a thin silicon system with an energy gap different from that of monocrystalline silicon. Film, thus forming a crystalline silicon solar cell with diffusion potential. The above-mentioned silicon-based thin film, for example, an amorphous silicon-based thin film is preferable. Among them, the thinner intrinsic amorphous silicon layer is between the conductive amorphous silicon thin film used to form the diffusion potential and the monocrystalline silicon substrate. It is the form of the crystalline silicon solar cell with the highest photoelectric conversion efficiency. one. However, the aforementioned solar cell is not limited to the aforementioned 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 laminate 301, a transparent electrode layer 302 formed on the main surface of the semiconductor laminate 301, and a collector 303 formed on the surface of the transparent electrode layer 302.

-Semiconductor laminated body-

The semiconductor laminate 301 includes an intrinsic silicon-based thin film 301A and a conductive silicon-based thin film 301B that are sequentially stacked on the main surface (hereinafter also referred to as the surface) on the light incident surface side of the substrate 200 (semiconductor substrate). In addition, the semiconductor laminate 301 is provided with an intrinsic silicon-based thin film 301C and a conductive type and the aforementioned one-conductive silicon-based thin film 301B that are sequentially laminated on the main surface (hereinafter also referred to as the back surface) of the substrate 200 opposite to the main surface. Different opposite conductivity type silicon thin film 301D. In addition, in this specification, "one conductivity type" refers to either n-type or p-type. In addition, the "reverse conductivity type" refers to a conductivity type different from the above-mentioned "one conductivity type". Specifically, for example, when the “one conductivity type” is an n-type, the “reverse conductivity type” is a p-type; and when the “one conductivity type” is a p-type, the “reverse conductivity type” is an n-type. The semiconductor laminate 301 constitutes the photoelectric conversion part of the solar cell 300. In addition, the intrinsic silicon film 301A, the one-conductivity silicon film 301B, the intrinsic silicon film 301C, and the reverse-conductivity silicon film 301D are collectively referred to as "silicon films 301A, 301B, 301C, and 301D" below.

-Substrate-

For example, the substrate 200 is a conductive single crystal silicon substrate. In addition, the n-type single crystal silicon substrate is a single crystal silicon substrate containing atoms (for example, phosphorus) for introducing electrons into silicon atoms. In addition, 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 an n-type or p-type single crystal silicon substrate, and an n-type single crystal silicon substrate is particularly preferable.

The shape of the substrate 200 is not particularly limited, but is square in plan view. , An octagon, rectangle, polygon, circle, etc. formed by cutting off the four corners of a square, preferably a square or octagon.

The size of the substrate 200 is not particularly limited, and is appropriately changed according to the specifications of the solar cell 300. Specifically, the width is, for example, 100 mm or more and 200 mm or less. In addition, in this specification, "width" has the following meanings: if it is a circle, it is the diameter of a circle; if it is a polygon, it is the distance between two opposite sides; if it is a rectangle, it is the length of the long side; if it is a square, it is the length of one side; If it is an octagon, the length of one side when it is square.

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

-Silicone film-

The silicon-based films 301A, 301B, 301C, and 301D are, for example, amorphous silicon-based 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. A conductive silicon-based thin film 301B and a reverse conductive silicon-based thin film 301D are p-type and n-type, or both n-type, or both p-type amorphous silicon thin films, preferably both p-type or both n-type amorphous silicon film.

The film forming method of the silicon-based thin films 301A, 301B, 301C, and 301D, for example, the plasma CVD method is preferable.

-Transparent electrode layer-

The transparent electrode layer 302 has a conductive oxide as a main component. The above-mentioned conductive oxides are, for example, zinc oxide, indium oxide, tin oxide, etc., which can be used alone or in combination. In particular, from the viewpoints of conductivity, optical characteristics, and long-term reliability, indium-based oxide whose main component is indium oxide is preferred. In this specification, the "main component" means that the content ratio is greater than 50% by mass, preferably 70% by mass or more, and more preferably 85% by mass or more. In addition, the above-mentioned conductive oxide used as the main component of the transparent electrode layer may preferably use at least one element such as Sn, W, As, Zn, Ge, Ca, Si, and C as a dopant depending on the use situation. Among them, indium tin oxide (ITO) using Sn as a dopant is particularly preferred.

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

-collector-

If there is only a transparent electrode layer in a heterojunction solar cell, the current extraction efficiency is poor, and the fill factor will decrease. The reason is as follows: Although the transparent electrode layer is formed with a conductive oxide as the main component, the resistivity of the conductive oxide is several orders of magnitude higher than that of metal. With only the transparent electrode layer, the series resistance ( Rs) is too large. Therefore, in order to prevent the increase of Rs and maintain a high fill factor, a collector electrode is used in a heterojunction solar cell.

Since the collecting electrode 303 is provided on the light incident surface side of the solar cell 300, it is preferable to have a pattern having a light-transmitting portion such as a comb tooth shape. If the collector 303 does not have a light-transmitting part, the light-shielding loss will increase, the light extraction amount will be reduced, and the short-circuit current will be reduced accordingly. The collector 303 preferably uses a material with high conductivity and chemical stability. Materials that meet this characteristic include silver or aluminum. The collector 303 is made of inkjet method, net Plate printing method, wire bonding method, spray method, vacuum evaporation method, sputtering method, electroplating method and other known techniques are made.

<Method of manufacturing solar cell>

As shown in FIG. 1, the manufacturing method of the solar cell 300 according to this embodiment includes: step S1 (filming process) of forming silicon-based thin films 301A, 301B, 301C, and 301D, and step S2 (making process) of forming a transparent electrode layer 302 Film manufacturing process) and step S3 of forming the collector 303.

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

For example, by mounting the substrate 200 on a tray and transporting it into a film forming apparatus, a desired thin film is formed on the main surface of the substrate 200 and the main surface opposite to the main surface to perform the film forming process.

Specifically, for example, as shown in FIG. 2, step S1 includes a preparation step S11, a mounting step S12, and a film forming step S13.

First, as shown in FIG. 3, the tray 100 is prepared in the preparation step S11. The tray 100 is used to transport the substrate 200 into the deposition chamber of a plasma CVD deposition apparatus (not shown). In addition, 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 the film forming material is vapor-deposited from the upper side on the main surface of the substrate 200 (refer to the arrow of the symbol P1 in FIG. 5), and the silicon-based film 301A is sequentially performed , 301B film production. After that, the substrate 200 is taken out of the plasma CVD film forming apparatus and the front and back surfaces are turned over, and then through the mounting step S12 and the film forming step S13, the silicon-based thin films 301C and 301D are sequentially performed on the opposite main surface of the substrate 200的filmmaking. Semiconductor Stacked body 301.

The obtained semiconductor layered body 301 is taken out from the plasma CVD film forming apparatus and mounted on the tray 100, or it is placed in another tray and carried into the PVD film forming apparatus. Then, the transparent electrode layer 302 is formed on both the front and back surfaces of the semiconductor laminate 301 (step S2). In the case of using another tray, a tray having the same structure as the tray 100 used in step S1 may be used, or a tray having another structure may be used.

Then, the semiconductor laminate 301 on which the transparent electrode layer 302 has been formed is taken out from the PVD film forming apparatus, and the pattern of the collector 303 is formed on both the front and back surfaces of the transparent electrode layer 302 by the various methods described above to obtain a solar cell 300 ( Step S3).

<tray>

Next, the structure of the tray 100 according to this embodiment will be described in detail. In addition, in the following description, the tray 100 used in step S1 is exemplified.

As shown in Figures 3 to 5, the tray 100 is a non-insulating component, which includes a flat main body 101 and a plurality of recesses 120. Each recess 120 is open on the surface 110 of the main body 101 on the side where the substrate 200 is mounted. Each recess 120 is square when viewed from above. The material of the non-insulating tray 100 includes metals such as titanium, aluminum, or stainless steel. However, the material of the tray 100 is not limited to metal, and the tray 100 can also be made of, for example, a carbon material. In addition, in the following description, for example, as shown in FIG. 3, for convenience, the side on which the substrate 200 is mounted is set to the upper side, and the other side opposite to the side is set to the lower side. In addition, 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 recess 120 includes an opening 121 formed on the surface 110 of the tray 100 and having a square shape in plan view, four side walls 122 extending downward from the opening 121, and a square bottom surface 124 connected to the lower ends of the four side walls 122. In addition, the four side walls The lower end of 122 forms the outer peripheral end 124A of the bottom surface 124.

In addition, the shape of the recess 120 is not limited to a square in a plan view, and can be appropriately changed to a rectangle, a polygon, a circle, or the like in a plan view according to the shape of the substrate 200. Alternatively, regardless of the shape of the substrate 200, it may be appropriately changed to a rectangular shape, a polygonal shape, a circular shape, or the like in a plan view.

The size of the recess 120, that is, the width W11 of the bottom surface 124, is slightly larger than that of the substrate 200. The details will be described later, that is, since the distance between the substrate 200 and the side wall 122 of the recess 120 is sufficiently small, the substrate 200 will not move significantly in the recess 120 during the transportation process of the tray 100 and the film forming process. It is possible to reduce damage to the substrate 200 and the like.

In addition, the size of the recess 120 is not limited to this structure, and can be appropriately changed according to the shape of the substrate 200, the specifications of the solar cell 300, and the like.

-Resin parts-

Here, a band-shaped resin member 130 is arranged on the bottom surface 124 of the recess 120.

The resin member 130 suppresses direct contact between the tray 100 and the substrate 200 after the substrate 200 has been installed in the recess 120. The resin member 130 is provided at two positions (a plurality of positions) of the outer peripheral portion 124B along the outer peripheral end 124A on the bottom surface 124 of the recess 120. In addition, it is preferable to arrange the resin member 130 in at least two positions of the outer peripheral portion 124B of the bottom surface 124 of the recess 120, and may be three or more positions. In addition, the shape of the resin member 130 is not limited to a belt shape, and may be other shapes such as a dot shape or a block shape.

As shown in FIG. 5, the resin member 130 has a two-layer laminated structure composed of an adhesive layer 132 in contact with the surface of the bottom surface 124 of the tray 100 and a heat-resistant resin layer 134 laminated on the upper side of the adhesive layer 132. In addition, the resin member 130 is not limited to a two-layer laminated structure, and may have a single-layer structure or a three-layer or more laminated structure. In the case where the resin component 130 has a three-layer or more laminated structure, it is preferable to let the tray The layer in contact with 100 is the adhesion layer 132, and the layer in contact with the substrate 200 is the heat-resistant resin layer 134.

The resin component 130 is fixed to the tray 100 with the adhesive layer 132. The main component of the adhesive layer 132 is epoxy resin, acrylic resin, or silicone resin. From the viewpoint of plasma resistance in the film forming process, etc., silicone resin is preferred.

The heat-resistant resin layer 134 is a layer that comes into contact with the substrate 200 after the upper substrate 200 is mounted in the mounting step S12, and is used to suppress contact and friction between the substrate 200 and the tray 100. The main components of the heat-resistant resin layer 134 are polyimide resin, polytetrafluoroethylene (PTFE) resin, polyolefin resin, and the like. From the viewpoint of plasma resistance in the film forming process, etc., a polyimide resin is preferred.

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. In addition, the thickness of the entire resin member 130 is, for example, 100 μm or less, preferably 80 μm or less, and more preferably 15 μm or more and 50 μm or less. Thereby, while ensuring sufficient elasticity of the resin member 130 for suppressing friction between the substrate 200 and the tray 100, it is also possible to suppress the diffusion of moisture, low molecular weight components, etc. during the film forming process.

In addition, from the standpoint of the ease of mounting work and removal work of the substrate 200, the heat-resistant resin layer 134 having appropriate sliding properties and anti-sticking properties is preferable. Specifically, from the viewpoint of improving slidability and anti-blocking properties, it is preferable that the surface of the heat-resistant resin layer 134 has a fine uneven shape. Such a concave-convex shape can be formed by adding a filler such as silica to the resin material forming the heat-resistant resin layer 134, or roughening treatment, or the like. The average surface roughness (Ra) as the surface roughness of the heat-resistant resin layer 134 is, for example, 10 nm or more and 100 nm or less, and particularly preferably 20 nm or more and 70 nm or less. In addition, sliding properties and anti-sticking properties are expressed through the coefficient of friction between the substrate 200 and the heat-resistant resin layer 134. For example, the static friction coefficient is preferably 0.4 or more and 0.5 or less, and the dynamic friction coefficient 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, a Bernoulli robot arm or the like. At this time, as shown in FIG. 4, the substrate 200 is preferably mounted on the resin member 130 in a manner to cover the entire resin member 130.

The plasma CVD method or PVD method in the film forming process is a plasma process in a vacuum environment. Moisture and low-molecular-weight components may be exposed to the radiant heat of the plasma in a vacuum environment and diffuse from the adhesive layer 132 and the heat-resistant resin layer 134 into the film forming chamber. These moisture and low-molecular-weight components can reduce the quality of the silicon-based films 301A, 301B and the transparent electrode layer 302, and are also the cause of pollution, which leads to the degradation of the performance of the solar cell.

It is preferable to arrange the resin member 130 in the tray 100 according to this embodiment in this way. That is, after the upper substrate 200 has been mounted in the mounting step S12, the outer peripheral end 136 of the resin member 130 is located inside the outermost end 201 of the substrate 200 when viewed from above. In other words, it is preferable that after the upper substrate 200 has been installed in the mounting step S12, the resin component 130 is completely covered by the substrate 200 in a plan view.

Specifically, referring to FIGS. 4 and 5, it is preferable that the following formula (1) is satisfied when the resin member 130 is arranged.

W1≧W2. . . . . . (1)

However, as shown in FIGS. 4 and 5, W1 is the shortest distance between the outer peripheral end 136 closest to the side wall 122 in the resin member 130 and the outer peripheral end 124A of the bottom surface 124 of the recess 120. W2 is the shortest distance between the outermost end 201 of the substrate 200 closest to the side wall 122 and the side wall 122. In addition, the shortest distance W2 is defined by the following formula (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. W2 is preferably 0.1mm or more and 2mm or less, 0.3mm or more and 0.9mm or less Better. In addition, the shortest distance W3 between the outermost end 201 of the substrate 200 and the outer peripheral end 136 of the resin member 130 expressed by the following formula (3) is preferably 0 mm or more and 44.9 mm or less, more preferably 0.05 mm Above 39.9mm.

W3=W1-W2. . . . . . (3)

With the above structure, in the film forming step S13, the influence of the radiant heat caused by the plasma entering the back side of the substrate 200 on the resin member 130 can be suppressed.

In addition, from the viewpoint of suppressing the surface of the substrate 200 from being contaminated by oxidants such as ozone components contained in the atmosphere and moisture, etc., it is preferable that the preparation step S11 and the mounting step S12 be performed under a predetermined range of oxidant concentration and a predetermined range of humidity. Specifically, the concentration of the oxidant is preferably 0 ppb or more and 10 ppb or less, and more preferably 0 ppb or more and 5 ppb or less. In addition, the relative humidity (RH) is preferably 40% RH or more and 70% RH or less, and the relative humidity (RH) is more preferably 50% RH or more and 60% RH or less.

<Effects>

In the film forming process, if the tray 100 according to this embodiment is used, the contact between the substrate 200 and the tray 100 and the friction between the two can be suppressed, and the occurrence of defects and the detachment of the thin film can be suppressed. The yield rate is improved. Specifically, the yield calculated in the appearance observation test described later is preferably 70% or more, more preferably 80% or more, and particularly preferably 90% or more.

In addition, in particular, by setting the arrangement and thickness of the resin member 130 within the above-mentioned range, and/or setting the oxidant concentration and humidity in the preparation step and mounting step of the tray 100 within the above-mentioned range, the photoelectric conversion of the solar cell 300 can be suppressed. The performance is reduced, and the durability of the solar cell 300 is improved. Specifically, the Voc calculated in the photoelectric conversion performance test described later is preferably 0.6V or more, more preferably 0.7V or more, and particularly preferably 0.7V or more and 0.8V or less. In addition, 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 addition, in the description of these embodiments, the same parts as those in the first embodiment will be assigned the same reference numerals and detailed descriptions will be omitted.

As shown in FIGS. 6 and 7, a through hole 126 may be formed in the central portion 124C of the bottom surface 124 of the recess 120. In this case, the main surface of the substrate 200 is taken as the lower side, and it is mounted on the resin member 130 arranged on the bottom surface 124. Then, a film forming material is vapor-deposited from below through the through hole 126 (see the arrow of symbol P2 in FIG. 7), and the silicon-based thin films 301A, 301B and the transparent electrode layer 302 are formed on the main surface of the substrate 200. The tray 100 according to the present embodiment is very suitable for a film forming apparatus of a deposition raising method. In addition, the size of the through hole 126 is not particularly limited, and can be appropriately determined according to the specifications of the solar cell 300 and the film forming apparatus, and the width W21 is, for example, 98 mm or more and 198 mm or less.

(Embodiment 3)

As shown in FIG. 8, in the tray 100 according to the first embodiment, not only the resin member 130 may be arranged on the outer peripheral portion 124B of the bottom surface 124 but also the resin member 130 may be arranged on the central portion 124C of the bottom surface 124. As a result, the contact and friction between the tray 100 and the substrate 200 can be 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 along the entire outer peripheral portion 124B of the bottom surface 124. As a result, the contact and friction between the tray 100 and the substrate 200 can be 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. In Figure 10 and Figure 11, the resin part The element 130 is arranged from the outer peripheral portion 121A of the opening portion 121 to the outer peripheral portion 124B of the side wall 122 and the bottom surface 124. In addition, it is preferable that the resin member 130 is arranged in at least two places of the opening 121 of the recess 120, and may be arranged in three or more places. In addition, the resin member 130 only needs to be arranged at least on the outer peripheral portion 121A of the opening 121, and it does not need to be arranged on the outer peripheral portion 124B of the side wall 122 and the bottom surface 124.

As shown in FIG. 10, when viewed from above, the entire recess 120 is covered when the substrate 200 is mounted. Furthermore, it is particularly preferable to mount the substrate 200 so as to cover the entire resin component 130. In other words, it is preferable to install the resin component 130 as described below. When the upper substrate 200 has been installed, the outer peripheral end 136 of the resin component 130 is located inside the outermost end 201 of the substrate 200 when viewed from above.

Specifically, it is preferable that the following formula (4) is satisfied when the resin member 130 is arranged.

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. In addition, the shortest distance W52 is defined by the following formula (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, more preferably 2 mm or more and 4 mm or less. 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. In addition, the shortest distance W53 between the outermost end 201 of the substrate 200 and the outer peripheral end 136 of the resin member 130 in plan view expressed by the following formula (6) 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. good.

W53=W52-W51. . . . . . (6)

Through the above structure, in the film forming process, the plasma can be prevented from entering the substrate The radiant heat generated on the back side of 200 affects the resin member 130.

If the tray 100 according to this embodiment is used, since the substrate 200 is larger than the recess 120, when the substrate 200 is deformed due to the radiant heat of the plasma during the film forming process, the central part of the substrate 200 can be prevented from contacting the tray 100, thereby It is possible to suppress the occurrence of defects and the deterioration of the quality of the film.

(Embodiment 6)

As shown in FIG. 12, in the tray 100 according to the fifth embodiment described above, the resin member 130 may be arranged along the entire circumference of the opening 121 of the recess 120. As a result, the contact and friction between the tray 100 and the substrate 200 can be effectively suppressed.

(Embodiment 7)

As shown in FIG. 13, in the tray 100 according to the fifth embodiment described above, the concave portion 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 surface and/or back surface of the substrate 200 may also have a texture structure. As a result, the semiconductor laminate 301 formed using the substrate 200 as a base also has a texture structure. Therefore, incident light is confined in the semiconductor laminate 301 as a photoelectric conversion unit, and the power generation efficiency of the solar cell 300 is improved. For example, the texture structure is formed by etching the surface and/or the back surface of the substrate 200.

For example, in Embodiment 1, etc., a photomask (not shown) may be provided above the substrate 200 in the film forming process. The photomask is used to prevent the film forming material from entering the surface of the substrate 200 on the opposite side to the surface on which the silicon-based thin films 301A, 301B and the transparent electrode layer 302 are formed. The photomask is provided to cover, for example, the peripheral portion of the substrate 200. In this case, the resin member 130 is arranged so as to be located inside the outer part of the mask when viewed from above. In other words, when viewed from above, the resin member 130 is completely covered by the substrate 200 and the photomask.

The silicon-based thin films 301A, 301B, the transparent electrode layer 302, and the collector electrode 303 may also be formed on both sides of the substrate 200. In this case, for example, while performing each step of step S1 to step S3 on the surface of the substrate 200, the surface and the back surface of the substrate 200 may be turned upside down to perform the same treatment on the back surface.

[Examples]

Hereinafter, specific implementation examples will be described.

<Production of solar cell samples>

The solar cell samples of Examples 1 to 7 and Comparative Example 1 shown in Table 1 were produced in the following order.

(Example 1)

The substrate 200 uses an n with an incident surface orientation of (100) and a thickness of 200μm. Type single crystal silicon wafer, and cut it into an octagon with a width W12 of 156.75 mm and four corners of 45 degrees. The 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 washed twice with ultrapure water. The silicon wafer was immersed in a 5 mass% KOH/15 mass% isopropanol mixed aqueous solution maintained at 70°C for 15 minutes to form a texture structure by etching the surface of the wafer. After that, it was washed twice with ultrapure water.

On the other hand, in the embodiment shown in FIGS. 3 to 5, the tray 100 has a square recess 120 (width W11=157mm), and a polyimide tape (produced by Teraoka Manufacturing Co., Ltd., Kapton tape 650S#25, thickness 50 μm, polyimide layer thickness 25 μm) was used as the resin member 130. In addition, the shortest distance W1 from the outer peripheral end 124A of the bottom surface 124 to the outer peripheral end 136 of the polyimide tape is 20 mm. In addition, the polyimide tape pasting work of the tray 100 and the wafer mounting work were performed in a clean room with an oxidant concentration of 8 ppb and a relative humidity of 55% RH.

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

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

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

As described above, the semiconductor laminate 301 fabricated as described above is taken out from the plasma CVD film forming apparatus, mounted in the recess 120 of the tray 100 of the same structure, and then transported as the sputtering device of the PVD film forming apparatus. In the plating device. Then, by a sputtering method, ITO with a film thickness of 100 nm was produced as a transparent electrode layer on the p-type amorphous silicon layer and the n-type amorphous silicon layer of the semiconductor laminate 301. The above-mentioned ITO used indium tin oxide as a target, substrate temperature: room temperature, pressure: in an argon and oxygen environment of 0.2 Pa, ^{a power density of 0.5 W/cm 2} was applied to form a film.

Next, the substrate is taken out from the sputtering device, and a comb-tooth-shaped collector is formed on the transparent electrode layer of the prepared photoelectric conversion part by using a screen printing method using silver flux.

In addition, a semiconductor laminate with electrodes was produced as described above and annealed at 180°C for 1 hour to obtain a solar cell sample.

(Example 2)

Except that the shortest distance W1 from the outer peripheral end 124A of the bottom surface 124 of the recess 120 of the tray 100 to the outer peripheral end 136 of the polyimide tape was set to 40 mm, the solar cell samples were produced in the same manner as in Example 1.

(Example 3)

Except that the shortest distance W1 from the outer peripheral end 124A of the bottom surface 124 of the recess 120 of the tray 100 to the outer peripheral end 136 of the polyimide tape was set to 0.125 mm, the same as in Example 1, a solar cell sample was produced.

(Example 4)

Except from the outer peripheral end 124A of the bottom surface 124 of the recess 120 of the tray 100 to the poly Except that the shortest distance W1 between the outer peripheral ends 136 of the imide tape was set to 0 mm, the other was the same as in Example 1, and a solar cell sample was produced.

(Example 5)

Except that a polyimide tape (Kapton tape 650S#25 produced by Teraoka Manufacturing Co., Ltd., thickness 100 μm, thickness of the polyimide layer 25 μm) was pasted as the resin member 130, the same as in Example 1, a solar cell sample was produced.

(Example 6)

Except that a PTFE tape (ASF-110FR, thickness 80 μm, PTFE layer thickness 23 μm, produced by Zhongxing Chemical Industry Co., Ltd.) was applied as the resin member 130, the same as in Example 1, and a solar cell sample was produced.

<Example 7>

Except that the storage of the tray 100 and the application of the polyimide tape were performed in an environment with an oxidant concentration of 15 ppb and a relative humidity of 90% RH, the other things were the same as in Example 1, and a solar cell sample was produced.

(Comparative example 1)

Except that the polyimide tape was not attached to the bottom surface 124 of the recess 120 of the tray 100, but the wafer was installed in the recess 120, the other things were the same as in Example 1, and a solar cell sample was produced.

<Appearance Observation Test>

Through the above-mentioned steps, 100 solar cell samples of Examples 1 to 7 and Comparative Example 1 were produced, and the appearance of the surface was visually observed by a tester. As a result of visual observation, a solar cell with a defect or a crack was regarded as a defective appearance, and a solar cell with no occurrence was regarded as a good appearance. The ratio of the number of good-looking products in 100 solar cell samples was calculated and expressed as a percentage, which was used as the yield rate of the solar cell samples shown in Table 1.

<Photoelectric conversion performance evaluation test>

For the solar cell samples judged to be excellent in appearance in the above-mentioned appearance observation test, the open voltage and short-circuit current as its photoelectric conversion performance were measured by measuring the voltage-current performance under the simulated sunlight of AM1.5 and 1sun.

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

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

<Research>

The yield of solar cell samples produced without arranging the resin components of Comparative Example 1 was 67%. In contrast, the yield of solar cell samples produced with the resin components of Examples 1 to 7 was 90% or more. After configuring the resin parts, the yield of solar cell samples has been improved.

In addition, when comparing the photoelectric conversion performance in Examples 1 to 7, compared with the solar cell samples of Example 6 using PTFE tape, the samples of Examples 1 to 5 and Example 7 using polyimide tape are compared with the solar cell samples of Example 6 using polyimide tape. The photoelectric conversion performance of the solar cell samples is more excellent.

In addition, in Examples 1 to 5 and 7, compared with the solar cell samples of Example 7 with higher oxidant concentration and humidity, the solar cell samples of Examples 1 to 5 with lower oxidant concentration and humidity had lower photoelectricity. The conversion performance is more excellent.

In addition, with regard to Examples 1 to 5, the solar cell samples of Examples 1 to 4 in which the thickness of the polyimide tape is 100 μm are compared with the solar cell samples of Example 5 in which the thickness of the polyimide tape is 50 μm. The photoelectric conversion performance is more excellent.

In addition, in Examples 1 to 4, the solar cell samples of Examples 1 to 3 satisfying W1≧W2 have more excellent photoelectric conversion performance than the solar cell samples of Example 4 where W1<W2.

100‧‧‧Tray (Substrate Tray)

101‧‧‧(The main body of the pallet)

110‧‧‧(The surface of the pallet)

120‧‧‧Concave

121‧‧‧Opening

122‧‧‧Sidewall

124‧‧‧Bottom

130‧‧‧Resin parts

200‧‧‧Substrate (semiconductor substrate)

Claims (11)

A substrate tray, in order to transport the semiconductor substrate to the film forming chamber in the film manufacturing process for manufacturing solar cells, the semiconductor substrate is mounted on the substrate tray, the substrate tray having a flat body, recesses, and resin parts The recessed portion is open on the surface of the main body on the side where the semiconductor substrate is mounted, the resin member is arranged on at least one of the bottom surface of the recessed portion and the outer peripheral portion of the recessed portion of the main body, and has elasticity, and the semiconductor substrate is not in contact with The main body is attached to the resin member in contact with each other. A method for manufacturing a solar cell includes a film forming process for forming a thin film on a semiconductor substrate. The film forming process includes: preparing a substrate tray for transporting the semiconductor substrate to a film forming chamber, and transferring the semiconductor substrate The step of mounting on the substrate tray, wherein the substrate tray has a flat body, a recess and a resin member, the recess is open on a surface of the body on a side where the semiconductor substrate is mounted, and the resin member is arranged on the body At least one of the bottom surface of the recessed portion and the outer peripheral portion of the recessed portion has elasticity, and in the mounting step, the semiconductor substrate is mounted on the resin member without contacting the main body. The method for manufacturing a solar cell according to claim 2, wherein in the mounting step, the semiconductor substrate is mounted on the resin member so as to cover the entire resin member. The method of manufacturing a solar cell as described in claim 3, wherein the shape of the semiconductor substrate is square or octagonal, The shape of the recess is a square with a width larger than the width of the semiconductor substrate in plan view, and the resin component is arranged at a plurality of positions on the outer periphery of the bottom surface of the recess or the entire circumference of the outer periphery, and the semiconductor substrate is mounted on the resin component After mounting, the outer peripheral end of the resin member is located inside the outermost end of the semiconductor substrate. The method of manufacturing a solar cell according to claim 3, wherein the shape of the semiconductor substrate is a square or an octagon, the shape of the recess is a square having a width smaller than that of the semiconductor substrate in plan view, and the resin member is arranged on the After the semiconductor substrate has been mounted on the resin member at a plurality of locations on the outer periphery of the recess or the entire periphery of the outer periphery, the outer periphery of the resin member is located inside the outermost end of the semiconductor substrate. The method for manufacturing a solar cell according to claim 2, wherein the resin member has a laminated structure of two or more layers. The method for manufacturing a solar cell according to claim 6, wherein the resin member includes an adhesive layer in contact with the surface of the substrate tray, and a heat-resistant resin layer in contact with the semiconductor substrate. The method for manufacturing a solar cell as described in claim 7, wherein the main component of the adhesive layer is silicone resin. The method for manufacturing a solar cell according to claim 7, wherein the main component of the heat-resistant resin layer is polyimide. The method for manufacturing a solar cell according to claim 9, wherein the thickness of the heat-resistant resin layer is 10 μm or more and 25 μm or less, and the thickness of the resin member is 15 μm or more and 50 μm or less. The method for manufacturing a solar cell as described in any one of claims 2 to 10, wherein the above-mentioned preparation steps and the above-mentioned installation steps are carried out in an environment with an oxidant concentration of 0ppb or more and 10ppb or less and a humidity of 40%RH or more and 70%RH or less .

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