JP7063709B2 - Equipment for manufacturing substrates with transparent conductive film, manufacturing method for substrates with transparent conductive film - Google Patents

Description

The present invention relates to an apparatus for manufacturing a substrate with a transparent conductive film and a method for manufacturing a substrate with a transparent conductive film, wherein transparent conductive films having different hydrogen contents are arranged on the front surface side and the back surface side of the substrate.

In recent years, solar cells having a heterojunction between crystalline silicon and amorphous silicon (a-Si) (hetero-type crystalline Si solar cells) have higher conversion efficiency than conventional crystalline silicon solar cells. Attention has been paid. In a hetero-type crystalline Si solar cell, TCO (Transparent Conducting Oxide) is usually formed on amorphous silicon arranged on both sides of crystalline silicon. Here, TCO is a transparent material that conducts electricity, and examples thereof include indium oxide, tin oxide, and zinc oxide.

The TCO arranged on the light receiving surface side of the solar cell is particularly required to have both low resistance and high transmittance. As one of the measures to solve this problem, a solar cell in which a transparent conductive film containing hydrogen is provided on the light receiving surface side is known (Patent Document 1).
However, from the viewpoint of the solar cell device, the amorphous silicon (a-Si) that forms the base of the TCO is in contact with the plasma containing hydrogen gas to generate _H2O , which is the amorphous silicon (a-Si). ), There is a problem that an insulating layer is formed at the interface between the amorphous silicon (a—Si) and the TCO deposited on the amorphous silicon (a—Si). Since the existence of such an insulating layer becomes a factor that hinders the electrical flow in the stacking direction, the development of a solution thereof has been expected.

International Publication No. 2013/061637

The present invention has been made in view of the above circumstances, and is a device for manufacturing a substrate with a transparent conductive film, which comprises transparent conductive films having different hydrogen contents arranged on the front surface side and the back surface side of the substrate. It is an object of the present invention to provide a method for manufacturing a substrate with a film.

The apparatus for manufacturing a substrate with a transparent conductive film according to claim 1 of the present invention is provided on the front surface side and the back surface side of the substrate together with a third temperature control means for heat-treating the substrate placed on the tray, respectively. A device for manufacturing a substrate with a transparent conductive film, which includes a film forming chamber provided with a first film forming means and a second film forming means for forming the first transparent conductive film and the second transparent conductive film.
In the film forming chamber, the first process of supplying a first process gas containing hydrogen to the vicinity of the first target forming the first transparent conductive film on the surface side of the substrate, which forms the first film forming means. The gas outlet of the gas introduction mechanism is arranged at a position where the first process gas is sprayed on the target located on the upper side of the first target in the direction in which the substrate moves.
In the film forming chamber, a second process gas containing no hydrogen is supplied in the vicinity of the second target forming the second transparent conductive film on the back surface side of the substrate, which forms the second film forming means. The gas outlet of the process gas introduction mechanism is arranged,
When the substrate passes in front of the first target, the first transparent conductive film is formed on the surface side of the substrate by a sputtering method, and the substrate passes in front of the second target. The first target and the second target are arranged in the film forming chamber so that the second transparent conductive film is formed on the back surface side of the substrate by a sputtering method.

According to claim 1, the apparatus for manufacturing a substrate with a transparent conductive film according to claim 2 of the present invention communicates the film forming chamber with an internal space located between the first target and the second target. As such, it is characterized in that one or more exhaust means provided with an intake port are arranged.

The apparatus for manufacturing a substrate with a transparent conductive film according to claim 3 of the present invention supports, in claim 1, an opening for the tray to expose the front surface and the back surface of the substrate, and a side surface of the substrate. A plurality of the trays are arranged linearly side by side in the traveling direction in the film forming chamber having a portion, and a specific tray among the plurality of trays is in front of the first target and the second target. Has a portion that overlaps the leading tray and the trailing tray located in front of and behind the specific tray in the traveling direction, and the specific tray is provided from the first target side or the second target side. When looking at, move each tray so that the specific tray forms a group with the leading tray and the trailing tray located in front of and behind it, and the leading tray and the trailing tray are on one side with the specific tray in between. It is characterized by having means for controlling.

The apparatus for manufacturing a substrate with a transparent conductive film according to claim 4 of the present invention is the position in claim 1 before the substrate passes in front of the first target and the second target in the film forming chamber. In the internal space in the above and in the internal space at the position where the film formation is performed by passing in front of each target, one or more of the third temperature controlling means are arranged for each internal space. It is characterized by.

The apparatus for manufacturing a substrate with a transparent conductive film according to claim 5 of the present invention has the first transparent conductive film on the surface side of the substrate, which serves as the first film forming means in the film forming chamber according to claim 1. The gas lead-out unit of the first process gas introduction mechanism that supplies the first process gas containing hydrogen toward the discharge space generated between the first target forming the above and the moving substrate is the first. It is characterized in that it is arranged at a position where the process gas is sprayed.

In claim 1 or 5, the apparatus for manufacturing a substrate with a transparent conductive film according to claim 6 of the present invention is first transparent on the surface side of the substrate forming the first film forming means in the film forming chamber. It is characterized in that a chimney is arranged so as to surround the discharge space generated between the first target forming the conductive film and the moving substrate.

The apparatus for manufacturing a substrate with a transparent conductive film according to claim 7 of the present invention is placed on a tray introduced from an atmospheric atmosphere in front of the film forming chamber in any one of claims 1 to 6. The preparation chamber L provided with the first temperature control means for heat-treating the substrate having the a-Si film on the front surface and the back surface in the prepared state in a reduced pressure atmosphere, and the tray and the substrate moved from the preparation chamber. A heating chamber H provided with a second temperature control means for heat treatment is provided, and in the subsequent stage of the film forming chamber, a transport chamber for cooling the tray and the substrate moved from the film forming chamber and a transport chamber moved from the transport chamber. It is characterized by having a take-out chamber for leading the heat-treated tray and the substrate from the reduced pressure atmosphere to the atmospheric atmosphere.

The method for manufacturing a substrate with a transparent conductive film according to claim 8 of the present invention is to manufacture a substrate with a transparent conductive film having at least a charging chamber, a heating chamber, a film forming chamber, a transport chamber, and a taking-out chamber according to claim 7. It is a method of manufacturing a substrate with a transparent conductive film, which forms a transparent conductive film on the a-Si film arranged on the front surface and the back surface of the substrate placed on the tray by using an apparatus, and is a heat treatment temperature in the charging chamber. When the maximum value of is defined as _TL [° C], the maximum value of the heat treatment temperature in the heating chamber is TH [° C], and the maximum value of the heat treatment temperature in the film formation chamber is T _SP [° _C ], _TL is defined. It is characterized in that it satisfies the relational expression of ≧ T _SP or _TH ≧ T _SP .

The method for manufacturing a substrate with a transparent conductive film according to claim 9 of the present invention is the method of claim 8, wherein in the internal space of the charging chamber and the internal space of the heating chamber, the substrate is on the front surface side and the back surface thereof. It is characterized in that it is heat-treated by the first temperature control means and the second temperature control means, which are arranged on the side respectively.

The method for manufacturing a substrate with a transparent conductive film according to claim 10 of the present invention is the internal space in the film forming chamber, which is located before the substrate passes in front of the first target. Further, in the internal space where the substrate passes in front of the first target and the film formation is performed, the substrate is heat-treated by the third temperature control means arranged on the non-deposit surface side thereof. It is characterized by being done.

The method for manufacturing a substrate with a transparent conductive film according to claim 11 of the present invention is the internal space in the film forming chamber, which is located before the substrate passes in front of the second target. Further, in the internal space where the substrate passes in front of the second target and the film formation is performed, the substrate is heat-treated by the third temperature control means arranged on the non-deposit surface side thereof. It is characterized by being done.

The transparent conductive film-attached substrate manufactured by the method for manufacturing a transparent conductive film-attached substrate of the present invention is, for example, a first transparent conductive film and a second transparent film on a-Si films arranged on the front surface and the back surface of the substrate, respectively. A substrate with a transparent conductive film on which a conductive film is arranged, the hydrogen content C _H1 [atoms / cm ³ ] contained in the first transparent conductive film, and the hydrogen content C contained in the second transparent conductive film. When defined as _H2 [atoms / cm ³ ], the relational expression of _CH1 > _CH2 is satisfied .

The substrate with a transparent conductive film preferably has ¹⁰²¹ units of _CH1 and ¹⁰²⁰ units of _CH2 [atoms / cm ³ ] .

As the solar cell according to the present invention, for example, a substrate with a transparent conductive film having a first transparent conductive film and a second transparent conductive film arranged on a-Si films arranged on the front surface and the back surface of the substrate is provided. The solar cell has a hydrogen content _CH1 [atoms / cm ³ ] contained in the first transparent conductive film and a hydrogen content contained in the second transparent conductive film, with the surface side of the substrate as the light incident surface. When the quantity C _H2 [atoms / cm ³ ] is defined, an example includes a substrate with a transparent conductive film satisfying the relational expression of C _H1 > C _H2 .

It is preferable that the above-mentioned solar cell has ₁₀₂₁ units of ^CH1 and ¹⁰²⁰ units of _CH2 [atoms / cm ³ ] .

According to the apparatus for manufacturing a substrate with a transparent conductive film (hereinafter also referred to as TCO) according to the present invention, the first film forming means uses a first target and a process gas containing hydrogen, and is specified to be located in the previous stage in the film forming chamber. A first transparent conductive film is formed on the surface side of the substrate by a sputtering method in the internal space of. Next, the second film forming means uses a second target and a process gas containing no hydrogen to form a second transparent conductive film on the back surface side of the substrate by a sputtering method in a specific internal space located at the subsequent stage in the film forming chamber. .. In other words, although the manufacturing apparatus of the present invention exists in the same film forming chamber, the first transparent conductive film containing hydrogen is placed on the surface side of the substrate in a specific film forming space located in the preceding stage in the traveling direction of the substrate. After the film is formed, a hydrogen-free second transparent conductive film can be formed on the back surface side of the substrate in a specific film forming space located in the subsequent stage.
Therefore, the manufacturing apparatus of the present invention uses a process gas containing hydrogen on the surface side of the substrate with respect to the substrate in which amorphous silicon (a-Si) forming the base of TCO is previously provided on both the front and back surfaces of the substrate. Even if H ₂ O is generated by contact with a plasma containing hydrogen gas when the first transparent conductive film is formed, the amorphous silicon on the back surface side of the substrate is generated by wrapping around the back surface side of the substrate. The problem that an insulating layer is formed at the interface between the amorphous silicon (a—Si) on the back surface side of the substrate and the TCO deposited on the amorphous silicon (a—Si) due to reattachment to a—Si) is solved.
Therefore, the present invention provides a manufacturing apparatus that contributes to the formation of a substrate with a transparent conductive film in which transparent conductive films having different hydrogen contents are arranged on the front surface side and the back surface side of the substrate.

The method for manufacturing a substrate with a transparent conductive film according to the present invention uses a substrate manufacturing apparatus with a transparent conductive film having at least a charging chamber, a heating chamber, a film forming chamber, a transport chamber, and a taking-out chamber, and a substrate placed on a tray. Before the transparent conductive film is formed on the a-Si film arranged on the front surface and the back surface of the film while being heat-treated in the film forming chamber, the heat treatment is performed in the preparation chamber and the heating chamber in advance.
The heat treatment conditions at that time are as follows: the maximum value of the heat treatment temperature in the charging chamber is _TL [° C.], the maximum value of the heat treatment temperature in the heating chamber is _TH [° C.], and the maximum value of the heat treatment temperature in the film formation chamber is set. When each is defined as T _SP [° C.], it is assumed that the relational expression of T _L ≧ T _SP or _TH ≧ T _SP is satisfied.
By controlling the maximum value of each heat treatment temperature in the preparation chamber, the heating chamber, and the film formation chamber so as to satisfy this relational expression, the tray is placed on the tray in the preparation chamber and the heating chamber located in front of the film formation chamber. The substrate reaches its peak temperature. The substrate placed on the tray moved to the film forming chamber is kept at a temperature lower than this peak temperature. As a result, the discharge and carry-in of water in the film forming chamber by the substrate placed on the tray are reduced.
Therefore, according to the method for manufacturing a substrate with a transparent conductive film according to the present invention, the discharge and carry-in of water in the film forming chamber are reduced, so that the transparent conductive film having different hydrogen contents on the front surface side and the back surface side of the substrate. It is possible to stably form a substrate with a transparent conductive film on which a film is arranged.

A substrate with a transparent conductive film in which a first transparent conductive film and a second transparent conductive film are arranged on a-Si films arranged on the front surface and the back surface of the substrate by the above-mentioned manufacturing apparatus and manufacturing method of the present invention, respectively. Is defined as the hydrogen content C _H1 [atoms / cm ³ ] contained in the first transparent conductive film and the hydrogen content C _H2 [atoms / cm ³ ] contained in the second transparent conductive film. In this case, a substrate with a transparent conductive film satisfying the relational expression of _CH1 > _CH2 is obtained. As a result, the substrate with a transparent conductive film of the present invention has a configuration in which transparent conductive films having different hydrogen contents are arranged on the front surface side and the back surface side of the substrate, and the front surface side of the substrate is utilized as a light incident surface. Since it can be used, it is suitable for solar cell applications.

A substrate with a transparent conductive film in which a first transparent conductive film and a second transparent conductive film are arranged on a-Si films arranged on the front surface and the back surface of the substrate by the above-mentioned manufacturing apparatus and manufacturing method of the present invention, respectively. Is obtained. By using this substrate with a transparent conductive film, the surface side of the substrate is used as a light incident surface, and the hydrogen content _CH1 [atoms / cm ³ ] contained in the first transparent conductive film is used for the second transparent conductive film. When the hydrogen content contained is defined as C _H2 [atoms / cm ³ ], a solar cell satisfying the relational expression of C _H1 > C _{H 2} is obtained. A solar cell having this configuration can improve the curve factor (FF: Fill Factor) and the power generation efficiency (Eff). The curve factor is "the value obtained by dividing the maximum output (Pmax) by the product of the open circuit voltage (Voc) and the short circuit current (Isc)", and the power generation efficiency is "the open circuit voltage (Voc) and the short circuit current density (Jsc)". , The product of the curve factors (FF) ".

The cross-sectional view which shows an example of the manufacturing apparatus of the substrate with a transparent conductive film. FIG. 3 is a cross-sectional view showing an example of a substrate placed on a tray. An enlarged cross-sectional view showing a gas lead-out unit in a configuration example in which two targets are used. An enlarged cross-sectional view showing a gas outlet portion in a configuration example in which three targets are used. FIG. 2 is a cross-sectional view showing an example of a substrate with a transparent conductive film and a solar cell including the substrate. The flowchart which shows the manufacturing method of the conventional substrate with a transparent conductive film. The flowchart which shows the manufacturing method of the substrate with a transparent conductive film which concerns on embodiment of this invention. A list showing tray temperatures in Experimental Examples 1 to 4 of the present invention. The graph which shows the tray temperature in Experimental Examples 1 to 4 of this invention. The figure which shows the profile of the hydrogen content of a transparent conductive film (when H ₂ O / Ar = 0%). The figure which shows the profile of the hydrogen content of a transparent conductive film (in the case of H ₂ O / Ar = 6%).

Hereinafter, the best mode of the manufacturing apparatus and manufacturing method of the substrate with a transparent conductive film according to the present invention will be described with reference to the drawings. It should be noted that the present embodiment is specifically described in order to better understand the gist of the invention, and is not limited to the present invention unless otherwise specified.

<First Embodiment>
In the following, FIG. 5 describes a method for manufacturing a substrate with a transparent conductive film, in which a transparent conductive film is arranged so as to cover the a-Si film on a substrate whose front surface and back surface are both covered with an a-Si film. Will be described with reference to.
FIG. 5 is a cross-sectional view showing an example of a substrate with a transparent conductive film and a solar cell including the substrate.
In FIG. 5, the substrate 101 (substrate) constituting the transparent conductive film-attached substrate 10A (10) is a flat-plate crystalline silicon substrate, and both the front surface 101a and the back surface 101b of the substrate 101 are formed of an a—Si film. It is covered. In FIG. 5, the (downward) arrow pointing toward the surface 101a of the substrate 101 indicates the light incident direction.

The a-Si film (denoted as α in FIG. 5) provided on the surface 101a on the light incident side includes an i-type a-Si film 102 provided in contact with the surface 101a and the i-type a-Si. It is composed of a p-type a—Si film 103 provided on the film 102. Further, the first transparent conductive film 104 is provided so as to cover the p-type a-Si film 103 forming the outer surface of the a-Si film (α). Further, an electrode 105 made of a metal film is arranged on the outer surface of the first transparent conductive film 104.

On the other hand, the a-Si film (indicated as β in FIG. 5) arranged on the back surface 101b on the non-light incident side is the i-type a-Si film 112 provided in contact with the back surface 101b. It is composed of an n-type a-Si film 113 provided on the i-type a-Si film 112 and the n-type a-Si film 113. Further, a second transparent conductive film 114 is provided so as to cover the n-type a-Si film 113 forming the outer surface of the a-Si film (β). Further, an electrode 115 made of a metal film is arranged on the outer surface of the second transparent conductive film 114.

In the present invention, the hydrogen content contained in the first transparent conductive film 104 and the second transparent conductive film 114 is controlled by the manufacturing apparatus and manufacturing method of the substrate with the transparent conductive film described later. That is, when defined as the hydrogen content C _H1 [atoms / cm ³ ] contained in the first transparent conductive film 104 and the hydrogen content C _H2 [atoms / cm ³ ] contained in the second transparent conductive film, C _H1 > It is controlled so as to satisfy the relational expression of _CH2 . As a result, the substrate with a transparent conductive film of the present invention has a configuration in which transparent conductive films having different hydrogen contents are arranged on the front surface side and the back surface side of the substrate, and the front surface side of the substrate is utilized as a light incident surface. Since it can be used, it is suitable for solar cell applications.

Hereinafter, the structure in which the a—Si film (α) and the a—Si (β) are arranged with respect to the substrate 101 is referred to as an intermediate structure 1A (1). The structure in which the first transparent conductive film 104 and the second transparent conductive film 114 are arranged with respect to the intermediate structure 1A (1) is the substrate 10A (10) with a transparent conductive film. Further, the solar cell 100A (100) is a structure in which a crystalline silicon base material is used as the substrate 101 and the electrodes 105 and 115 are arranged on the substrate 10A (10) with a transparent conductive film.

The transparent conductive film-attached substrate 10A (10) having the first transparent conductive film 104 and the second transparent conductive film 114 having the above-mentioned configuration (FIG. 5) manufactured by the manufacturing apparatus and manufacturing method of the present invention described in detail later From Table 2 described later, it was confirmed that the substrate has a structure in which transparent conductive films having different hydrogen contents are arranged on the front surface side and the back surface side. The substrate with a transparent conductive film having this configuration is suitable for solar cell applications because the surface side of the substrate can be used as a light incident surface.
Further, it was found that the solar cell using the substrate with the transparent conductive film having the above structure can improve the curve factor (FF: Fill Factor) and the power generation efficiency (Eff).

Although not explicitly shown in FIG. 5, an antireflection layer (Anti Reflection Layer: AR layer) may be arranged on the surface 101a side of the substrate 101, if necessary. As the antireflection layer, for example, an insulating nitride film, a silicon nitride film, a titanium oxide film, an aluminum oxide film and the like are preferably used.

6 and 7 are flowcharts showing a method of manufacturing a substrate with a transparent conductive film, FIG. 6 shows a conventional example, and FIG. 7 shows an embodiment of the present invention. The embodiments of the present invention differ from the conventional examples in the steps of "S16, S17" described in detail below.

The conventional substrate with a transparent conductive film is formed through the process flow of S51 to S58 shown in FIG. That is, "c-Si (n) preparation, texture formation (both sides), i-type a-Si formation (both sides), p-type a-Si formation (front surface), n-type a-Si formation (back surface), waterless TCO. It is manufactured by sequentially performing eight process treatments of "formation (front surface), water (or no water) TCO formation (back surface), and electrode formation (both sides)".

In particular, in the conventional method for manufacturing a substrate with a transparent conductive film, a "water-free process gas" is used when forming a TCO film on the front surface side which is a light receiving surface, and the back surface side which is a non-light receiving surface is used. When the TCO film is formed, the "process gas containing water" is used, and when the film is formed in this order, the "process gas containing water" used when forming the TCO film on the back surface side is used. The electrode is formed on the TCO film surface on the surface side, which has been formed in advance, and has water adhered to the TCO film surface. Therefore, there is a possibility that an electrical defect may occur between the TCO on the surface side and the electrode.

On the other hand, the substrate with a transparent conductive film of the present invention is formed through the process flow of S11 to S18 shown in FIG. 75. That is, "c-Si (n) preparation, texture formation (both sides), i-type a-Si formation (both sides), p-type a-Si formation (front surface), n-type a-Si formation (back surface), TCO with water. It is manufactured by sequentially performing eight process treatments consisting of "formation (front surface), waterless TCO formation (back surface), and electrode formation (both sides)". When the film is formed in this order, the TCO film on the back surface side uses a "process gas that does not contain water", so even if it wraps around the TCO film surface on the front surface side that has already been film-formed in advance, the TCO film on the front surface side. There is no risk of water adhering to the surface. As a result, the electrode is formed on the TCO film surface on the surface side without being affected by water. Therefore, the problem that an electrical defect occurs between the TCO on the surface side and the electrode is solved.

In order to manufacture the above-mentioned substrate with a transparent conductive film of the present invention, for example, an apparatus for manufacturing a substrate with a transparent conductive film as shown in FIG. 1 is suitable. FIG. 2 is a cross-sectional view showing an example of a substrate placed on a tray in the manufacturing apparatus of FIG. Hereinafter, the apparatus for manufacturing a substrate with a transparent conductive film according to the present invention will be described in detail with reference to FIGS. 1 and 2.

<Spattering equipment>
In the method for manufacturing a substrate with a transparent conductive film in the present invention, the a—Si film (α, β) corresponding to the substrate of the transparent conductive film is previously formed on the substrate 101 by a known CVD apparatus. Here, the two transparent conductive films 104 (TCO1) and 114 (TCO2) can be formed by a manufacturing apparatus (hereinafter referred to as a sputtering apparatus) 700 for forming a film by a sputtering method as shown in FIG. The manufacturing apparatus 700 is an in-line sputtering apparatus, which is a horizontal conveying type sputtering apparatus provided with a conveying mechanism for horizontally holding and conveying the substrate 101. The discharge type in the sputtering apparatus 700 is not limited to DC, and may be RF or (DC + RF) superimposition.

In the sputtering apparatus shown in FIG. 1, a plurality of process chambers [preparation chamber L, heating chamber H, film formation inlet chamber ENT, first film formation chamber SP1, second film formation chamber SP2, third film formation chamber SP3, first 4 film formation chamber SP4, film formation outlet chamber EXT, transfer chamber B, take-out chamber UL] are connected and arranged in series. The tray 400 on which the substrate 101 [intermediate structure 1A (1)] on which the a—Si film (α, β) is formed passes through each process chamber in order, so that the transparent conductivity according to the embodiment of the present invention is obtained. A film is made on the intermediate structure 1A (1).

That is, as will be described later, in the present invention, the substrate 101 heat-treated to a desired temperature passes through the four film forming chambers (SP1 → SP2 → SP3 → SP4), whereby the surface side of the substrate 101 [light]. On the a—Si film (α) used as the incident surface], a “first transparent conductive film 104 (TCO1) having a high hydrogen content” is formed, and the back surface side of the substrate 101 [used as a non-light incident surface]. On the a-Si film (β)], a second transparent conductive film 114 (TCO2) having a low hydrogen content is formed.

When the first transparent conductive film 104 (TCO1) and the second transparent conductive film 114 (TCO2) are formed by the sputtering method, the tray 400 having the configuration shown in FIG. 2 is preferably used. That is, the tray 400 has a main body 401 having a first opening 400a and a second opening 400b for exposing the front surface α and the back surface β of the substrate 101 to be treated, and a second body located inside the main body 401. It is composed of one protruding portion 402 and second protruding portions 403a and 403b located outside the main body 401.

The first protrusion 402 places the substrate 101 inside the main body 401 so that the first opening 400a is set larger than the second opening 400b. As a result, the first opening 400a is defined by the inner side surface 401s of the main body 401, and the second opening 400b is defined by the inner side surface 402s of the protrusion 402. This is because the first transparent conductive film 104 (TCO1) on the light incident side is formed in a larger area than the second transparent conductive film 114 (TCO2) on the non-light incident side.

Second protrusions 403a and 403b are provided on the outside of the main body 401. In the traveling direction of the tray (also referred to as a specific tray) 400 (in the direction of the arrow in FIG. 2), the second protruding portion 403a extending in the direction of the advanced tray (also referred to as the leading tray) 410 and the backward tray (backward). The second projecting portion 403b extending in the direction of the (also referred to as a tray) 420 is provided with the connection position with the main body 401 turned upside down. That is, the second protrusion 413b is arranged on the advanced tray 410 so as to overlap the second protrusion 403a of the tray 400. Similarly, the second protruding portion 423a is arranged on the tray 420 to be moved backward so as to overlap the second protruding portion 403b of the tray 400.

As a result, the second protrusion 403a of the tray 400 and the second protrusion 413b of the advanced tray 410 are kept in an overlapping state, and the second protrusion 403b of the tray 400 and the second protrusion 423a of the tray 420 to be moved backward overlap each other. While maintaining the state, the three trays 400, 410, and 420 are connected to perform spatter film formation of the first transparent conductive film 104 (TCO1) and the second transparent conductive film 114 (TCO2).

In the manufacturing apparatus of the present invention, the trays 400, 410, and 420 on which the substrate 101 is placed are connected in the traveling direction of the trays, and there is no gap between the trays. Therefore, the possibility that the sputter particles reach the non-deposited surface of the substrate 101 (for example, when the front surface is a film-formed surface, the back surface is the non-deposited surface) is greatly reduced through the voids between the trays. Similarly, the wraparound of the process gas to be sputtered is suppressed.

Therefore, the present invention can avoid problems such as sputter particles adhering to the non-deposited surface of the substrate 101 and the non-deposited surface of the substrate 101 being exposed to the process gas used for sputtering. Brings the manufacturing equipment of. This action / effect is "used as a light incident surface on the surface side of the substrate 101 by passing the substrate 101 heat-treated to a desired temperature through four film forming chambers (SP1 → SP2 → SP3 → SP4). On the a-Si film (α) to be formed], a "first transparent conductive film 104 (TCO1) having a high hydrogen content" is formed, and the back surface side of the substrate 101 [the a-Si film used as a non-light incident surface]. On (β)], a second transparent conductive film 114 (TCO2) having a low hydrogen content is formed. ”In the present invention, it works extremely effectively.

The sputtering apparatus of FIG. 1 has a plurality of process chambers [preparation chamber L, heating chamber H, film formation inlet chamber ENT, first film formation chamber SP1, second film formation chamber SP2, third film formation chamber SP3, fourth formation. The film chamber SP4, the film formation outlet chamber EXT, the transport chamber B, and the take-out chamber UL] are connected and arranged in series. The sputtering apparatus of FIG. 1 is provided with a mechanism (not shown) for mounting the substrate 101 [intermediate structure 1A (1)] from the charging chamber L to the taking-out chamber UL and transporting the substrate 101 while keeping it horizontal. ..

In the sputtering apparatus of FIG. 1, the reference numerals DV1 to DV6 all represent door valves. The first door valve DV1 cuts off the space between the air space outside the device and the internal space of the charging chamber L. The second door valve DV2 cuts off between the internal space of the charging chamber L and the internal space of the heating chamber H. The third door valve DV3 shuts off between the internal space of the heating chamber H and the internal space of the film formation inlet chamber ENT. The fourth door valve DV4 shuts off between the internal space of the film formation outlet chamber EXT and the internal space of the transport chamber B. The fifth door valve DV5 shuts off between the internal space of the transport chamber B and the internal space of the take-out chamber UL. The sixth door valve DV6 shuts off between the internal space of the take-out chamber UL and the atmospheric space outside the device.

In the sputtering apparatus of FIG. 1, six chambers (the film forming inlet chamber ENT, the first film forming chamber SP1, the second film forming chamber SP2, the third film forming chamber SP3, the fourth film forming chamber SP4, and the film forming are formed. The internal space of the outlet chamber EXT) is all in communication, forming one vacuum chamber. In the six chambers, the "dashed-dotted line" indicating the partition between the chambers in the adjacent positions means that the internal spaces of the chambers in the adjacent positions communicate with each other.

Both the front surface and the back surface of the substrate 101 [intermediate structure 1A (1)] mounted on the tray 400 carried into the internal space of the charging chamber L from the external space of the sputtering apparatus are previously subjected to a known CVD apparatus. An a-Si film is formed. The substrate 101 can be moved only in the forward direction from the charging chamber L to the taking-out chamber UL while being mounted on the tray 400. That is, in the manufacturing apparatus shown in FIG. 1, the substrate 101 mounted on the tray 400 does not need to return in the reverse direction [direction from the take-out chamber UL to the charging chamber L]. Therefore, the sputtering apparatus of FIG. 1 is excellent in mass productivity.

The first door valve DV1 is opened and closed, and the substrate 101 is carried from the atmospheric space (outside the sputtering apparatus) into the internal space of the charging chamber L. The first exhaust means P11 is used to make the internal space of the charging chamber L a desired depressurized atmosphere. If necessary, heat treatment is performed from both sides of the substrate 101 in the charging chamber L by using the temperature controlling means H11 and H12 in the charging chamber L. The substrate 101 without heat treatment or the substrate 101 having reached a desired temperature by heat treatment performs an opening / closing operation of the second door valve DV2 and is moved from the charging chamber L to the heating chamber H.

Next, the substrate 101 moved from the charging chamber L to the heating chamber H is heat-treated from both sides of the substrate 101 by the temperature control means H21 and H22 at the point A. At that time, the second exhaust means P21 is used for the internal space of the heating chamber H, and a desired depressurized atmosphere is maintained. The substrate 101 having reached a desired temperature in the heating chamber H opens and closes the third door valve DV3, and is moved from the heating chamber H to the film formation inlet chamber ENT.

Next, the substrate 101 moved from the heating chamber H to the film formation inlet chamber ENT is heat-treated from both sides of the substrate 101 by the temperature control means H311 and H312 at the point B. The substrate 101 having reached the desired temperature in the film forming inlet chamber ENT passes through the internal spaces of the four film forming chambers (SP1 → SP2 → SP3 → SP4) from the film forming inlet chamber ENT to form a desired film formation. After that, it is moved to the film forming outlet chamber EXT.

The atmosphere of the film forming inlet chamber ENT in which the substrate 101 is housed is the substrate 101 in the first film forming chamber SP1, the second film forming chamber SP2, the third film forming chamber SP3, and the fourth film forming chamber SP4 located in the subsequent stage. It is adjusted according to the atmospheric conditions (spatter film forming conditions and the like) when the first transparent conductive film 104 (TCO1) and the second transparent conductive film 114 (TCO2) formed on the front and back surfaces of the above are formed.

In the first film forming chamber SP1 located next to the film forming inlet chamber ENT, a temperature control means H322 for heat-treating the back surface of the substrate 101 when the substrate 101 passes the point C is arranged. This makes it possible to adjust the temperature of the substrate 101 immediately before the formation of the first transparent conductive film 104 (TCO1) performed in the next second film forming chamber SP2.

In the second film forming chamber SP2 located next to the first film forming chamber SP1, the temperature control means H332 for heat-treating the back surface of the substrate 101 when the substrate 101 passes the point D, and the surface side of the substrate 101 A first film forming means composed of a pair of rotating targets TG21 and TG22 for forming the first transparent conductive film 104 (TCO1) is arranged. As a result, the film formation temperature of the substrate 101 at the time of forming the first transparent conductive film 104 (TCO1) can be adjusted from the back surface (lower surface in FIG. 1) which is a non-deposition surface. The outlets of the two process gas supply means G21 and G22 are arranged at positions on the upper side in the traveling direction of the substrate 101 with respect to the pair of rotation targets TG21 and TG22.

The temperature-adjusted substrate 101 passes through the point D of the second film forming chamber SP2. At this time, the tray 400 keeps the substrate 101 horizontally so that the surface of the substrate 101 faces the first targets TG21 and TG22. By passing the substrate 101 through the point D by the tray 400, the first transparent conductive film 104 (TCO1) is formed only on the surface side of the substrate 101 by, for example, the DC sputtering method using the first targets TG21 and TG22. To. As a result, the first transparent conductive film 104 (TCO1) is formed on the a—Si film (α) on the surface (101b) side of the substrate 101. As described above, the discharge type of the sputtering method in the present invention is not limited to DC, and may be RF or (DC + RF) superposition.

At that time, as the first process gas for forming the plasma, an inert gas (for example, Ar) G21 and a gas containing a reactive gas (for example, _O2 gas) or hydrogen (for example, _H2O ) G22 are used in the traveling direction of the substrate. It is supplied so as to blow toward the target TG21 on the good side. In the second film forming chamber SP2, the first targets TG21 and TG22 are arranged above the substrate 101, and depot down sputtering is performed.

FIG. 3 is an enlarged cross-sectional view showing a gas lead-out unit in a configuration example in which two targets are used. The pair of targets shown in FIG. 3 represents a pair of first targets TG21 and TG22 arranged in the second film forming chamber SP2 of FIG. In FIG. 3, reference numeral 400 is a tray on which the substrate is mounted, and a thick white arrow (pointing to the right on the paper surface) indicates the direction in which the tray (that is, the substrate) moves.

As shown in FIG. 3, in the film forming chamber, in the vicinity of the first targets TG21 and TG22 that form the first film forming means and form the first transparent conductive film on the surface side of the substrate, the first process is performed. Of the gases, the gas lead-out portion (arrow) of the first process gas introduction mechanism that supplies the gas G22 containing reactive gas or hydrogen moves in the direction in which the substrate moves [(in FIG. 3, from the right end to the right side of the tray 400). In the direction of the thick white arrow (extending)], it is preferable that the configuration is arranged at a position where the first process gas G22 is blown toward the target TG21 located on the upper side of the first targets TG21 and TG22. According to this configuration, hydrogen is consumed at the cathode on the upper side, and a film formation with less hydrogen can be performed at the cathode on the lower side. As a result, in the first transparent conductive film formed on the surface side of the substrate, the initial growth portion has a high hydrogen concentration, and the hydrogen concentration can be lowered as the film thickness increases.

In FIG. 3, among the first process gases, the gas out-licensing part of the first process gas introduction mechanism that supplies the inert gas G21 is not shown, but it is a gas G22 containing a reactive gas or hydrogen. Similarly, it is not always necessary to dispose of it on the upper side, and it may be arranged on the lower side, for example.

Further, instead of the above-mentioned configuration (a configuration in which the first process gas G22 is blown toward the target TG21), the first transparent conductivity is formed on the surface side of the substrate forming the first film forming means in the film forming chamber. The first process gas introduction mechanism that supplies the first process gas G22 containing hydrogen toward the discharge space (plasma) generated between the first targets TG21 and TG22 forming the film and the moving substrate. The gas lead-out unit may be arranged at a position where the first process gas G22 is sprayed. As a result, a state in which hydrogen is evenly contained in the discharge space (plasma) can be realized, so that the first transparent conductive film formed on the substrate can have a uniform hydrogen content in the film.

In the configuration of FIG. 3, that is, in the configuration in which the first target consists of two cylindrical targets TG21 and TG22, the chimney arrangement is effective. When the chimneys are arranged in the configuration of FIG. 3, it is preferable to provide the chimneys C21 and C22 so as to surround the two first targets TG21 and TG22. By providing the chimney, the first process gas G22 containing hydrogen, which is used to form the first transparent conductive film on the front surface side of the substrate, forms a film on the back surface side of the substrate (of the second transparent conductive film). It is possible to suppress the influence on the formation).

FIG. 4 is an enlarged cross-sectional view showing a gas lead-out unit in a configuration example in which three targets are used.
FIG. 3 shows a configuration in which the first targets TG21 and TG22 are paired, but the present invention is not limited thereto. For example, as shown in FIG. 4, the first target consists of three cylindrical targets TG21, TG22, and TG23, and the direction in which the substrate moves [(in FIG. 4, extending from the right end to the right side of the tray 400) is outlined. The present invention can also be applied to a configuration in which TG23, TG21, and TG22 are arranged side by side in order from the upper side to the lower side in the direction of the thick arrow. TG21 and TG22 in FIG. 4 are a pair of first targets similar to those in FIG.

When the first target TG23 is independently located in the front stage and the second and third first targets TG21 and TG22 are paired and located in the rear stage in the direction in which the substrate moves. It suffices that the gas outlet of the first process gas introduction mechanism that supplies the first process gas is provided only to the first target TG23 that is independently located in the previous stage. At that time, the gas out-licensing unit of the first process gas introduction mechanism that supplies the first process gas to the first target TG23 is not limited to the upper side in the direction in which the substrate moves, for example, the lower side or the like. It may be arranged in.

The first process gas supplied to the first target TG23 located in the previous stage can also be supplied to the first targets TG21 and TG22 in the subsequent stage by flowing in the direction of the first targets TG21 and TG22 in the subsequent stage. As a result, the gas out-licensing unit (gas out-licensing unit as shown in FIG. 3) of the first process gas introduction mechanism that supplies the first process gas to the first targets TG21 and TG22 in the subsequent stage is necessarily configured in FIG. It is not necessary to dispose of it in.

The chimney arrangement is also effective in the configuration of FIG. 4, that is, in the configuration in which the first target is composed of three cylindrical targets TG21, TG22, and TG23. When the chimneys are arranged in the configuration of FIG. 4, the first chimneys C23 and C24 are provided so as to surround the first first target TG23, and the second and third first targets TG21, It is preferable to provide the second chimneys C21 and C22 so as to surround the TG22. As a result, even in the configuration of FIG. 4, the effect of providing the chimney [the first process containing hydrogen used for forming the first transparent conductive film on the surface side of the substrate, as in the configuration of FIG. 3 described above. The effect of suppressing the influence of the gas G22 on the film formation (formation of the second transparent conductive film) on the back surface side of the substrate] can be stably obtained.

The first target may be composed of four or more cylindrical targets. When there are four first targets, that is, the above-mentioned pair of target arrangements may be repeated twice. Similarly, when there are five first targets, one first target and a pair of target placements may be repeated twice. That is, the present invention can be applied both when the first target is composed of an even number of cylindrical targets and when the first target is composed of an odd number of cylindrical targets.

In the third film forming chamber SP3 located next to the second film forming chamber SP2, a temperature control means H331 that heat-treats the surface of the substrate 101 when the substrate 101 passes the point E is arranged.

In the fourth film forming chamber SP4 located next to the third film forming chamber SP3, the temperature control means H341 for heat-treating the surface of the substrate 101 when the substrate 101 passes the point F, and the back surface side of the substrate 101 A second film forming means composed of a pair of rotating targets TG41 and TG42 for forming the second transparent conductive film 114 (TCO2) is arranged. As a result, the film formation temperature of the substrate 101 at the time of forming the second transparent conductive film 114 (TCO2) can be adjusted from the surface (upper surface in FIG. 1) which is a non-deposition surface. The outlets of the two process gas supply means G41 and G42 are arranged at positions on the upper side in the traveling direction of the substrate 101 with respect to the two pairs of rotation targets TG41 and TG42.

The temperature-adjusted substrate 101 passes through the point F of the fourth film forming chamber SP4. At this time, the tray 400 keeps the substrate 101 horizontally so that the back surface of the substrate 101 faces the second targets TG41 and TG42. By passing the substrate 101 through the point F by the tray 400, the second transparent conductive film 114 (TCO2) is formed only on the back surface side of the substrate 101 by, for example, the DC sputtering method using the second targets TG41 and TG42. To. As a result, the second transparent conductive film 114 (TCO2) is formed on the a—Si film (β) on the back surface (101b) side of the substrate 101. As described above, the discharge type of the sputtering method in the present invention is not limited to DC, and may be RF or (DC + RF) superposition.

At that time, as the process gas for forming the plasma, the inert gas (for example, Ar gas) G41 or the reactive gas (for example, _O2 gas) G42 is used as the target TG41 on the upper side or the target TG42 on the lower side in the traveling direction of the substrate. It is supplied to blow toward. In the fourth film forming chamber SP4, the targets TG41 and TG42 are arranged below the substrate 101, and depot-up sputtering is performed.

In other words, in the film forming chamber, a second process that does not contain hydrogen in the vicinity of the second targets TG41 and TG42 that form the second transparent conductive film on the back surface side of the substrate, which forms the second film forming means. A gas outlet of the second process gas introduction mechanism for supplying gas is arranged. For example, the gas outlet of the second process gas introduction mechanism faces the target TG41 located on the upper side or the target TG42 located on the lower side of the second targets TG41 and TG42 in the direction in which the substrate moves. , The configuration arranged at the position where the second process gas is blown is preferable, but the present invention is not limited to this configuration.

The second target is also not limited to the above-mentioned pair of configurations. Similar to the first target described above, the second target may be arranged by arranging three cylindrical targets side by side, or four or more cylindrical targets may be arranged side by side as the second target. That is, the present invention can be applied both when the second target is composed of an even number of cylindrical targets and when the second target is composed of an odd number of cylindrical targets.

FIG. 1 discloses a manufacturing apparatus having a specification configuration in which film formation is not performed in the first film forming chamber SP1 and the third film forming chamber SP3, but the present invention is not limited to this configuration. For example, the first film forming chamber SP1 may be provided with the same film forming means as the second film forming chamber SP2. The third film forming chamber SP3 may be provided with the same film forming means as the fourth film forming chamber SP4.

In the sputtering apparatus of FIG. 1, six chambers (the film forming inlet chamber ENT, the first film forming chamber SP1, the second film forming chamber SP2, the third film forming chamber SP3, the fourth film forming chamber SP4, and the film forming are formed. In the outlet chamber EXT), a plurality of exhaust means (P31, P332, P331, P352) are arranged in order to create a reduced pressure atmosphere in the communicated internal space. That is, for example, a partition valve, a door valve, a differential pressure valve, and the like are not provided between the six chambers between the film forming chambers located at adjacent positions. As a result, the above-mentioned "configuration in which a plurality of trays (for example, trays 400, 410, 420) are connected and moved in the traveling direction" can be realized.

The third exhaust means P31 is connected to a position where the internal space of the film formation inlet chamber ENT is mainly exhausted. The fourth exhaust means P332 is connected to a position where the internal space of the second film forming chamber SP2 is mainly exhausted. The fifth exhaust means P331 is connected to a position where the internal space of the third film forming chamber SP3 is mainly exhausted. The sixth exhaust means P352 is connected to a position where the internal space of the film formation outlet chamber EXT is mainly exhausted.

Above all, the fourth exhaust means P332 and the fifth exhaust means P331 are important. The fourth exhaust means P332 mainly includes the internal space of the second film forming chamber SP2 in which the film forming means composed of a pair of rotating targets TG11 and TG22 for forming the first transparent conductive film 104 (TCO1) is arranged. Exhaust. The fifth exhaust means P331 is in front of the internal space of the fourth film forming chamber SP4 in which the film forming means composed of two pairs of rotation targets TG41 and TG42 for forming the second transparent conductive film 114 (TCO2) is arranged. The internal space of the third film forming chamber SP3, which is located, is mainly exhausted.

As a result, the fourth exhaust means P332 and the fifth exhaust means P331 have the process gas [hydrogen content] introduced from the two process gas supply means G21 and G22 for forming the first transparent conductive film 104 (TCO1). Gas for forming a large amount of the first transparent conductive film 104 (TCO1)] does not affect the film formation of the second transparent conductive film 114 (TCO2) having a low hydrogen content, which is located in the subsequent step. Works for.

A device that assists the function so as not to affect the film formation of the second transparent conductive film 114 (TCO2) having a low hydrogen content, which is located in the subsequent step, is the above-mentioned "three trays 400, 410, 420". Is connected to form a sputter film formation of the first transparent conductive film 104 (TCO1) and the second transparent conductive film 114 (TCO2). " In the manufacturing apparatus of the present invention, since a plurality of trays (for example, trays 400, 410, 420) are connected and move in the traveling direction, there is no gap between the trays, so that the gap between the trays is passed through. The possibility that the sputter particles reach the non-deposited surface of the substrate 101 (for example, when the front surface is a film-formed surface, the back surface is the non-deposited surface) is greatly reduced. Similarly, the wraparound of the process gas to be sputtered is suppressed. Therefore, according to the present invention, the second transparent conductive film 114 (TCO2) having a low hydrogen content, which is produced after forming the first transparent conductive film 104 (TCO1), can be stably formed.

In this way, by passing through the four film forming chambers (SP1 → SP2 → SP3 → SP4), the surface side of the substrate 101 [on the a—Si film (α) used as the light incident surface] is “. The first transparent conductive film 104 (TCO1) having a high hydrogen content is formed, and the back surface side of the substrate 101 [on the a-Si film (β) used as a non-light incident surface] has a low hydrogen content. A substrate 101 on which the second transparent conductive film 114 (TCO2) is formed is obtained. The substrate 101 that has passed through the four film forming chambers (SP1 → SP2 → SP3 → SP4) is moved by the tray 400 to the point G in the internal space of the film forming outlet chamber EXT.

After the substrate 101 on which the first transparent conductive film 104 (TCO1) and the second transparent conductive film 114 (TCO2) are formed is moved to the film formation outlet chamber EXT (point G), the fourth door valve DV4 is opened and closed. Then, the film is moved from the film forming outlet chamber EXT to the transport chamber B.

After being moved to the transport chamber B (point H), the fifth door valve DV5 is opened and closed, and the fifth door valve DV5 is moved from the transport chamber B to the take-out chamber UL (point I). After that, the pressure inside the take-out chamber UL was set to atmospheric pressure, and then the sixth door valve DV6 was opened and closed to form the first transparent conductive film 104 (TCO1) and the second transparent conductive film 114 (TCO2). The substrate 101 is carried out of the sputtering apparatus.

As described above, in the sputtering apparatus of FIG. 1, the gas containing hydrogen introduced into the internal space of the second film forming chamber SP2 located in the front stage flows out to the internal space of the fourth film forming chamber located in the rear stage. In order to prevent this from happening, the arrangement of providing the fourth exhaust means P332 and the fifth exhaust means P331 with respect to the pair of rotation targets TG11 and TG22 for forming the first transparent conductive film 104 (TCO1) was devised.

Further, in the sputtering apparatus of FIG. 1, the gas containing hydrogen introduced into the internal space of the second film forming chamber SP2 located in the front stage flows out to the internal space of the fourth film forming chamber located in the rear stage. In order to prevent this, the tray 401 on which the substrate 101 is placed and moved is also devised. That is, in the traveling direction of the trays, the trays 400, 410, and 420 on which the substrate 101 is placed are connected, and the trays 400, 410, and 420 move in a connected state so that there is no gap between the trays. It was possible.

The present invention provides a sputtering apparatus capable of significantly suppressing the wraparound of process gas to be sputtered from one surface side to the other surface side (for example, from the front surface side to the back surface side) of the substrate by devising such an exhaust means and a tray. Bring.

Further, since the sputtering apparatus of FIG. 1 is an in-line sputtering apparatus, it is possible to manufacture a substrate (and a solar cell) with a transparent conductive film with high productivity, and the footprint of the apparatus can be reduced. It has the advantage of. Further, in the case of an in-line sputtering apparatus, it is suitable for producing a uniform film under the same film forming conditions.

On the other hand, when a general single-wafer manufacturing apparatus is used, each time a single substrate is processed, the previously formed substrate (post-deposited substrate) is transferred from the film forming chamber to the moving chamber (transfer chamber). It is necessary to take out the substrate (the substrate before film formation) to be deposited next and transfer it from the moving chamber to the film forming chamber. Further, it is also necessary to clean the film-forming chamber by removing the residual gas in the film-forming chamber after taking out the film-forming substrate, and then transport the pre-deposition substrate into the film-forming chamber. However, in this case, the residual component is not completely removed from the film forming chamber due to the residual component of the residual gas adhering to the wall portion of the film forming chamber or the like, and the residual component is formed later on the film. May affect the characteristics of. Further, when the film is formed on the substrate, the process gas is introduced and the process gas introduction is stopped in the film forming chamber, and the discharge is turned on / off. In this case, it is necessary to control the amount of water adsorbed on the undercoat every time one substrate is processed, which tends to make the process difficult.

On the other hand, when the in-line sputtering apparatus is used, the substrate 101 moves only in the forward direction from the charging chamber L to the taking-out chamber UL, passes through the internal space in which the substrate 101 communicates, and a-on both sides of the substrate 101. Since the first transparent conductive film 104 (TCO1) and the second transparent conductive film 114 (TCO2) are formed on the Si film (α, β), respectively, the amount of water adsorbed on the a-Si film which is the undercoat film. It has the advantage of simplifying the control of. Further, since the power is always turned on, the time contributing to the film formation is 100 [%], and high productivity and low running cost can be achieved at the same time.

Further, in the sputtering apparatus of FIG. 1, in the film forming chambers (SP1, SP2, SP3, SP4) forming a continuous closed space, the a—Si films (α, β) on both sides of the substrate 101 are first, respectively. Since the transparent conductive film 104 (TCO1) and the second transparent conductive film 114 (TCO2) are formed into a film, the substrate 101 is not exposed to the atmospheric atmosphere, and the a-on both sides of the substrate 101 is maintained in a vacuum state. The first transparent conductive film 104 (TCO1) and the second transparent conductive film 114 (TCO2) can be formed on the Si film (α, β), respectively (vacuum consistent front and back film formation).

In the following, a plurality of process chambers [preparation chamber L, heating chamber H, film formation inlet chamber ENT, first film formation chamber SP1, second film formation chamber SP2, third film formation chamber] constituting the sputtering apparatus of FIG. 1 The results of verification of the tray temperature in SP3, the fourth film forming chamber SP4, the film forming outlet chamber EXT, the transport chamber B, and the take-out chamber UL] will be described.

FIG. 8 is a list showing the tray temperature [° C.] in Experimental Examples 1 to 4, in FIG. 8, "Pos." Is the name of the process chamber, and "Time" is the tray starting to move. For example, "240" represents "240 seconds after the start of moving the tray". The numbers described in the columns of Experimental Examples 1 to 4 are the temperature [° C.] of the tray (heat-treated by the temperature control means arranged in each process chamber) at that time (Time).
FIG. 9 is a graph showing the tray temperature [° C.] of FIG. In FIG. 9, the solid line shows Experimental Example 1, the short dotted line shows Experimental Example 2, the long dotted line shows Experimental Example 3, and the alternate long and short dash line shows Experimental Example 4.

<Experimental Example 1>
Under the setting conditions of Experimental Example 1, the temperature is gradually applied in the charging chamber L and the heating chamber H, and the temperature peaks are given in the four film forming chambers (SP1 to SP4, particularly SP3 and SP4). Therefore, the discharge of water from the tray surface into the internal space of the film forming chamber increases, which may adversely affect the process gas during sputtering.

<Experimental Example 2>
Under the setting conditions of Experimental Example 2, water is degassed from the tray surface by heating in the charging chamber L to give a temperature peak. In the process chamber located after the charging chamber L, the tray temperature is monotonically reduced. As a result, in the four film forming chambers (SP1 to SP4), it is possible to create a lower temperature state than at the time of the temperature peak, so that it is possible to reduce the discharge and carry-in of water.

<Experimental example 3>
Under the setting conditions of Experimental Example 3, water is sufficiently degassed from the tray surface by heating in the charging chamber L and the heating chamber H. After that, the degassing effect is enhanced by providing the high temperature holding time also in the film forming inlet chamber ENT and the four film forming chambers (SP1 to SP4).

<Experimental Example 4>
Under the setting conditions of Experimental Example 4, only vacuum exhaust is performed in the charging chamber L, and water is degassed from the tray surface by heating in the heating chamber H. After that, as in Experimental Example 3, the degassing effect is enhanced by providing a high temperature holding time in the film forming inlet chamber ENT and the four film forming chambers (SP1 to SP4). Although the temperature is raised slightly by adjusting the temperature at the time of film formation on the back surface, the effect of the released gas is minor because it has been heated and degassed in advance.

FIG. 10 is a diagram showing a profile of the hydrogen content of the transparent conductive film (when H ₂ O / Ar = 0%). FIG. 11 is a diagram showing a profile of the hydrogen content of the transparent conductive film (in the case of H ₂ O / Ar = 6%). 10 and 11 are the results obtained by SIMS analysis. The measuring instrument used for SIMS analysis is SIMS6650 manufactured by ULVAC-PHI. As the measurement conditions, the primary ion species was Cs ⁺ and the acceleration voltage was 5 kV.
In FIGS. 10 and 11, the horizontal axis is the depth of the transparent conductive film (the time when the transparent conductive film is dug from the front surface to the back surface of the transparent conductive film), and the left vertical axis is the hydrogen content [atoms / cm ³ ], and the vertical axis on the right shows the secondary ionic strength (16O, 115In, 28Si).

From FIGS. 10 and 11, the following points became clear.
The transparent conductive film of FIG. 10 corresponds to the above-mentioned second transparent conductive film 114 (TCO2), and its hydrogen content was in the range of 10 ²⁰ [atoms / cm ³ ].
The transparent conductive film of FIG. 11 corresponds to the above-mentioned first transparent conductive film 104 ( ^TCO1 ), and its hydrogen content was in the range of 1021 [atoms / cm ³ ].

Table 1 shows typical film forming conditions for forming the first transparent conductive film 104 (TCO1) and the second transparent conductive film 114 (TCO2). In the item column of Table 1, "Front" is the first transparent conductive film 104 (TCO1) formed on the front surface side of the substrate, and "Rear" is the second transparent conductive film 114 (TCO2) formed on the back surface side of the substrate. ) Means each.

From the above results, the substrate with a transparent conductive film of the present invention is a transparent conductive film in which a first transparent conductive film and a second transparent conductive film are arranged on a-Si films arranged on the front surface and the back surface of the substrate, respectively. A substrate with a film, defined as a hydrogen content C _H1 [atoms / cm ³ ] contained in the first transparent conductive film and a hydrogen content C _H2 [atoms / cm ³ ] contained in the second transparent conductive film. If so, it can be formed by satisfying the relational expression of _CH1 > _CH2 . At that time, the number of _CH1 is ¹⁰²¹ , and the number of _CH2 [atoms / cm ³ ] is ¹⁰²⁰ .

Table 2 shows the results of evaluating the hydrogen content C _H1 [atoms / cm ³ ] contained in the first transparent conductive film by changing the ratio of "water (H ₂ O) / Ar" under the Front conditions in Table 1. show.

Four types of solar cells having the configuration shown in FIG. 3 were manufactured. The four types of solar cells have different combinations of hydrogen content of the transparent conductive film [Front side TCO] provided on the front surface side (light receiving surface side) of the substrate and the transparent conductive film [Rear side TCO] provided on the back surface side of the substrate. bottom. Other configurations were the same. Experimental Examples 11 to 14 shown in Table 3 are four types of solar cells. As the evaluation results of the solar cell, the curve factor FF and the power generation efficiency Eff were evaluated.

The curve factor FF was 1.019 in the case of Experimental Example 11, 0.998 in the case of Experimental Example 12, and 1.007 in the case of Experimental Example 13, when standardized by the numerical values of Experimental Example 14.
The power generation efficiency Eff was 1.044 in the case of Experimental Example 11, 1.032 in the case of Experimental Example 12, and 1.010 in the case of Experimental Example 13, when standardized by the numerical values of Experimental Example 14.

From the above results, the hydrogen content C _H1 [atoms / cm ³ ] contained in the first transparent conductive film and the hydrogen content C _H2 contained in the second transparent conductive film, with the surface side of the substrate as the light incident surface. When defined as [atoms / cm ³ ], a solar cell (Experimental Example 11) that _satisfies the relational expression of _CH1 > CH2 has improved curve factor (FF: Fill Factor) and power generation efficiency (Eff). It turned out that it could be planned. The curve factor is "the value obtained by dividing the maximum output (Pmax) by the product of the open circuit voltage (Voc) and the short circuit current (Isc)", and the power generation efficiency is "the open circuit voltage (Voc) and the short circuit current density (Jsc)". , The product of the curve factors (FF) ".

Although the invention made by the present inventor has been specifically described above based on the embodiment, the present invention is not limited to the above embodiment and can be variously modified without departing from the gist thereof. Needless to say.

The present invention is widely applicable to an apparatus for manufacturing a substrate with a transparent conductive film, a method for manufacturing a substrate with a transparent conductive film, a substrate with a transparent conductive film, and a solar cell.

L charging room, H heating room, ENT film forming inlet room, SP1 first film forming room, SP2 second film forming room, SP3 third film forming room, SP4 fourth film forming room, EXT film forming exit room, B transport Room, UL take-out room, DV1, DV2, DV3, DV4, DV5, DV6 door valve, G21, G22 1st process gas introduction mechanism (process gas supply means for 1st transparent conductive film), G41, G42 2nd process gas introduction Mechanism (process gas supply means for the second transparent conductive film), H11, H12, H21, H22, H311, H312, H322, H332, H331, H341 temperature control means, P11, P21, P31, P331, P332, P352, P41, P52 Exhaust means, TG21, TG22 Rotating target for the first transparent conductive film (first film forming means), TG41, TG42 Rotating target for the second transparent conductive film (second film forming means), α, β a -Si film, 101 substrate, 104 first transparent conductive film (TCO1), 114 second transparent conductive film (TCO2), 400 trays, 700 sputtering apparatus.

Claims (11)

Along with a third temperature control means for heat-treating the substrate placed on the tray, a first film forming means for forming a first transparent conductive film and a second transparent conductive film on the front surface side and the back surface side of the substrate, respectively. And an apparatus for manufacturing a substrate with a transparent conductive film, which includes a film forming chamber provided with a second film forming means.
In the film forming chamber, the first process of supplying a first process gas containing hydrogen to the vicinity of the first target forming the first transparent conductive film on the surface side of the substrate, which forms the first film forming means. The gas outlet of the gas introduction mechanism is arranged at a position where the first process gas is blown toward the target located on the upper side of the first target in the direction in which the substrate moves.
In the film forming chamber, a second process gas containing no hydrogen is supplied in the vicinity of the second target forming the second transparent conductive film on the back surface side of the substrate, which forms the second film forming means. The gas outlet of the process gas introduction mechanism is arranged,
When the substrate passes in front of the first target, the first transparent conductive film is formed on the surface side of the substrate by a sputtering method, and when the substrate passes in front of the second target, the substrate is formed. A substrate with a transparent conductive film, wherein the first target and the second target are arranged in the film forming chamber so that the second transparent conductive film is formed on the back surface side of the substrate by a sputtering method. Manufacturing equipment. The film forming chamber is characterized in that one or more exhaust means provided with an intake port are arranged so as to communicate with an internal space located between the first target and the second target. The apparatus for manufacturing a substrate with a transparent conductive film according to claim 1. The tray has an opening for exposing the front surface and the back surface of the substrate, and a portion supporting the side surface of the substrate, and a plurality of the trays are linearly arranged in the traveling direction in the film forming chamber. Among the plurality of trays arranged, the specific tray is the preceding tray and the trailing tray located in front of and behind the specific tray in the traveling direction when passing in front of the first target and the second target. Each tray has an overlapping portion, and when the specific tray is viewed from the first target side or the second target side, the specific tray forms a group with the preceding tray and the following tray located in front of and behind the specific tray. The substrate with a transparent conductive film according to claim 1, further comprising a means for controlling the movement of each tray so that the leading tray and the trailing tray face one surface with the specific tray sandwiched between them. Manufacturing equipment. In the film forming chamber, an internal space at a position before the substrate passes in front of the first target and the second target, and an inside at a position where the film is formed by passing in front of each target. The apparatus for manufacturing a substrate with a transparent conductive film according to claim 1, wherein one or more of the third temperature controlling means are arranged in each internal space. In the film forming chamber, toward the discharge space generated between the first target forming the first transparent conductive film on the surface side of the substrate, which is the first film forming means, and the moving substrate. The transparency according to claim 1, wherein the gas outlet of the first process gas introduction mechanism for supplying the first process gas containing hydrogen is arranged at a position where the first process gas is sprayed. Equipment for manufacturing substrates with conductive films. In the film forming chamber, the discharge space generated between the first target forming the first transparent conductive film on the surface side of the substrate, which is the first film forming means, and the moving substrate is surrounded. The apparatus for manufacturing a substrate with a transparent conductive film according to claim 1 or 5, wherein a chimney is arranged in the surface. In the front stage of the film forming chamber, a first temperature control means for heat-treating a substrate introduced from an air atmosphere and placed on a tray and having an a-Si film on the front surface and the back surface in a reduced pressure atmosphere. A charging chamber L provided with the above, and a heating chamber H provided with a second temperature controlling means for heat-treating the tray and the substrate moved from the charging chamber.
In the subsequent stage of the film forming chamber, there is a transport chamber for cooling the tray and the substrate moved from the film forming chamber, and a take-out chamber for leading the tray and the substrate moved from the transport chamber from the reduced pressure atmosphere to the atmospheric atmosphere. The apparatus for manufacturing a substrate with a transparent conductive film according to any one of claims 1 to 6, wherein the apparatus comprises the above. Using the apparatus for manufacturing a substrate with a transparent conductive film having at least a charging chamber, a heating chamber, a film forming chamber, a transport chamber, and a take-out chamber according to claim 7, the substrates are arranged on the front surface and the back surface of the substrate placed on the tray. A method for manufacturing a substrate with a transparent conductive film, which forms a transparent conductive film on an a-Si film.
The maximum value of the heat treatment temperature in the preparation chamber is T _L [° _C ], the maximum value of the heat treatment temperature in the heating chamber is TH [° C], and the maximum value of the heat treatment temperature in the film formation chamber is T _SP [° C]. When defined, a method for manufacturing a substrate with a transparent conductive film, which satisfies the relational expression of _TL ≧ T _SP or _TH ≧ T _SP . In the internal space of the charging chamber and the internal space of the heating chamber, the substrate is heat-treated by the first temperature controlling means and the second temperature controlling means respectively arranged on the front surface side and the back surface side thereof. The method for manufacturing a substrate with a transparent conductive film according to claim 8. In the film forming chamber, an internal space at a position before the substrate passes in front of the first target, and an inside at a position where the substrate passes in front of the first target and film formation is performed. The method for manufacturing a substrate with a transparent conductive film according to claim 8, wherein the substrate is heat-treated by a third temperature control means arranged on the non-deposited surface side of the space. In the film forming chamber, an internal space at a position before the substrate passes in front of the second target, and an inside at a position where the substrate passes in front of the second target and film formation is performed. The method for manufacturing a substrate with a transparent conductive film according to claim 8, wherein the substrate is heat-treated by a third temperature control means arranged on the non-deposited surface side of the space.

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