JP2020033641A - Film deposition apparatus, film deposition method, and manufacturing method of solar cell - Google Patents

Abstract

To provide a technology for forming a high quality and uniform transparent conductive oxide film on both faces of a substrate to be used for, for example, a heterojunction type solar cell, in a passage type film deposition apparatus using a plurality of substrate holders.SOLUTION: A film deposition apparatus includes a first film deposition region 4 where sputter film deposition is performed on a first surface of a substrate 10, a first vacuum annealing mechanism 21 for vacuum annealing a first sputter film in an amorphous state formed on the first surface of the substrate 10 in the first film deposition region, downstream from the first film deposition region 4 in the conveying direction, a second film deposition region 5 where sputter film deposition is performed on a second surface of the substrate 10, and a second vacuum annealing mechanism 22 for vacuum annealing a second sputter film in an amorphous state formed on the second surface of the substrate 10 downstream from the second film deposition region 5 in the conveying direction, in a vacuum tank 2 capable of conveying the substrate 10 along a conveying passage.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a technology of a film forming apparatus for forming a film on both surfaces of a substrate by sputtering in a vacuum, and more particularly to a technology of forming a transparent conductive oxide film on both surfaces of a substrate of a heterojunction solar cell.

  In recent years, solar cells have been put to practical use as a clean and safe energy source. Among them, heterojunction type solar cells have attracted attention.

FIG. 19 is a cross-sectional view illustrating a schematic configuration of a general heterojunction solar cell.
As shown in FIG. 19, this heterojunction solar cell 100 has an i-type amorphous silicon layer 102, a p-type amorphous silicon layer 103, on one side (sunlight side) of an n-type crystalline silicon substrate 101. A first transparent conductive oxide film 104 and an electrode layer 105 are sequentially formed. Further, on the other surface of the n-type crystalline silicon substrate 101, an i-type amorphous silicon layer 106, an n-type amorphous silicon layer 107, a second The transparent conductive oxide film 108 and the electrode layer 109 are sequentially formed.

  Heterojunction solar cells can significantly reduce the power generation loss at the interface by passivating the amorphous silicon layer of the silicon wafer, and therefore have higher conversion efficiency and reduce the amount of silicon used compared to conventional crystalline solar cells. There are advantages such as being able to.

  In addition, the heterojunction solar cell has an advantage that high power generation efficiency can be achieved since power can be generated on both sides of the n-type crystalline silicon substrate.

  However, the heterojunction solar cell has a problem caused by the presence of a transparent conductive oxide film made of, for example, indium oxide on both sides of the n-type crystalline silicon substrate.

  That is, the transparent conductive oxide film on the light receiving surface side is required to have a particularly low resistance value and a high light transmittance, and this high light transmittance is required not only in the visible light region but also in the near infrared region. Achieving requires high carrier mobility.

  Conventionally, as a method for obtaining high carrier mobility, it is known to use a sputtering gas containing hydrogen when forming a transparent conductive oxide film by a sputtering method.

  This contributes to increasing the mobility of carriers by forming larger crystal grains and reducing crystal grain boundaries that cause carrier traps.

  In the process of obtaining high carrier mobility, annealing is performed on the amorphous film immediately after film formation by sputtering, whereby the transparent conductive oxide is crystallized and the particles are enlarged, resulting in high carrier mobility. It is.

  In such a conventional technique, the annealing process of the amorphous film is performed using the heat history when the electrode of the crystalline silicon solar cell is formed by firing. It is difficult to form a high-quality and uniform transparent conductive oxide film because it differs depending on the components.

  In addition, when the annealing temperature is low or the annealing time is insufficient, the intrinsic performance of the transparent conductive oxide film is not sufficiently exhibited, and as a result, the power generation efficiency of the crystalline silicon solar cell decreases. There was a problem that would.

JP 2011-146528 A

  The present invention has been made in view of such problems of the conventional technology, and an object thereof is to provide, for example, a heterojunction solar cell in a pass-through film forming apparatus using a plurality of substrate holders. An object of the present invention is to provide a technique for forming a high-quality and uniform transparent conductive oxide film on both surfaces of a substrate to be used.

In order to achieve the above object, the present invention provides a vacuum chamber capable of transporting a substrate along a transport path, and a first chamber provided in the vacuum chamber and configured to form a film on a first surface of the substrate. A first film formation region having a sputtering source, and an amorphous state formed on the first surface of the substrate in the first film formation region on the downstream side in the transport direction of the first film formation region. A first vacuum annealing mechanism for performing a vacuum annealing process on the first sputtered film, and a second sputtering source provided in the vacuum chamber and configured to form a film on a second surface of the substrate. And a second sputtered film in an amorphous state provided on the second surface of the substrate in the second film formation region and provided on the downstream side in the transport direction of the second film formation region. A second vacuum annealing mechanism for performing vacuum annealing on Is a film-forming apparatus having.
According to the present invention, a first vacuum annealing process is performed between the first vacuum annealing mechanism and the second film forming region on the first surface of the substrate that has been vacuum-annealed by the first vacuum annealing mechanism. This is a film forming apparatus provided with an annealing promoting vacuum annealing mechanism for further performing a vacuum annealing process on the sputtered film.
The present invention provides a vacuum chamber in which a single vacuum atmosphere is formed, and a first film formation region provided in the vacuum chamber and having a first sputtering source for forming a film on a first surface of a substrate. A second film formation region provided in the vacuum chamber and having a second sputtering source for forming a film on the second surface of the substrate, and formed so that a projection shape to a vertical plane becomes a series of rings. A transfer path provided to pass through the first and second film formation regions, an opening exposing first and second surfaces of the substrate, and holding the substrate in a horizontal state. A substrate holder transport mechanism that transports the substrate holder along the transport path, wherein the substrate holder transport mechanism moves the substrate holder through a first film formation region in a first direction. A first transport unit that transports the substrate in the transport direction, and the substrate holder that passes through the second film formation region. A second transport unit for transporting the substrate holder in a second transport direction opposite to the first transport direction, and the second transport unit from the first transport unit while maintaining the substrate holder in a vertical relationship. And a transport turn-back portion for transporting the substrate in a direction to be transported downstream of the first film-forming region of the first transport unit in an amorphous state formed on the first surface of the substrate. A first vacuum annealing mechanism for performing a vacuum annealing process on the first sputtered film is provided, and a first vacuum annealing process mechanism is provided downstream of the second film forming region of the second transport unit in the transport direction. This is a film forming apparatus provided with a second vacuum annealing mechanism for performing vacuum annealing on a second sputtered film in an amorphous state formed on two surfaces.
The first surface of the substrate that has been vacuum-annealed by the first vacuum annealing mechanism on the first transport direction side with respect to the second film-forming region of the second transport unit. This is a film forming apparatus provided with an annealing promoting vacuum annealing mechanism for further performing a vacuum annealing process on the first sputtered film.
The present invention is a film forming method for forming a film by sputtering on both surfaces of a substrate while moving the substrate in a vacuum, wherein a first sputtered film in an amorphous state is formed on a first surface of the substrate. A first film forming process, a first vacuum annealing process for performing a vacuum annealing process on the first sputtered film on the first surface of the substrate, and an amorphous state on the second surface of the substrate. A second film forming step of forming a second sputtered film, and a second vacuum annealing step of performing a vacuum annealing process on the second sputtered film on the second surface of the substrate Is the way.
The present invention is characterized in that after the first vacuum annealing process step of performing a vacuum annealing process on the first sputtered film in the amorphous state on the first surface of the substrate and on the second surface of the substrate, Before the second film forming step of forming the second sputtered film, a film forming method having an annealing promoting step of further performing a vacuum annealing process on the first sputtered film on the first surface of the substrate is there.
According to the present invention, the substrate is provided with an i-type amorphous silicon layer and a p-type amorphous silicon layer sequentially on a first surface of an n-type crystalline silicon substrate, and on a second surface of the n-type crystalline silicon substrate, a substrate on which an i-type amorphous silicon layer and an n-type amorphous silicon layer are sequentially provided, wherein the first sputtered film is a first transparent conductive oxide film, and the second sputtered film is a second transparent conductive oxide film. This is a film formation method that is a conductive oxide film.
According to another aspect of the present invention, there is provided a film forming method using the film forming apparatus described above, wherein the first transport unit of the substrate holder transport mechanism passes the substrate holder through the first film forming region. A first deposition step of transporting the first transport direction along the transport path and forming a first sputtered film by sputtering on a first surface of the substrate held by the substrate holder; The substrate holder is transported in the first transport direction along the transport path by a first transport unit of the substrate holder transport mechanism, and the first sputter film on the first surface of the substrate is moved. A first vacuum annealing process for performing a vacuum annealing process by the first vacuum annealing mechanism, and the transfer path in a state where the substrate holder is maintained in an up-down relationship by a transfer turning portion of the substrate holder transfer mechanism. Along the said Returning the substrate holder from the transfer unit to the second transfer unit, and transferring the substrate holder through the second film formation region by the second transfer unit of the substrate holder transfer mechanism. A second deposition step of transporting the second transport direction along the transport path and forming a second sputtered film by sputtering on a second surface of the substrate held by the substrate holder; The substrate holder is transported in the second transport direction along the transport path by a second transport unit of the substrate holder transport mechanism, and the second holder is transported with respect to the second sputtered film on the second surface of the substrate. And a second vacuum annealing step of performing a vacuum annealing process by the second vacuum annealing mechanism.
According to another aspect of the present invention, there is provided a film forming method using the film forming apparatus described above, wherein the first transport unit of the substrate holder transport mechanism passes the substrate holder through the first film forming region. A first deposition step of transporting the first transport direction along the transport path and forming a first sputtered film by sputtering on a first surface of the substrate held by the substrate holder; The substrate holder is transported in the first transport direction along the transport path by a first transport unit of the substrate holder transport mechanism, and the first sputter film on the first surface of the substrate is moved. A first vacuum annealing process for performing a vacuum annealing process by the first vacuum annealing mechanism, and the transfer path in a state where the substrate holder is maintained in an up-down relationship by a transfer turning portion of the substrate holder transfer mechanism. Along the said Returning the substrate holder from the transfer unit to the second transfer unit and transferring the substrate holder along the transfer path by the second transfer unit of the substrate holder transfer mechanism in the second transfer direction. The first sputtered film on the first surface of the substrate that has been vacuum-annealed by the first vacuum annealing mechanism is further subjected to vacuum annealing by the annealing promoting vacuum annealing mechanism. An annealing promoting step, and transporting the substrate holder in the second transport direction along the transport path so as to pass through the second film formation region by a second transport unit of the substrate holder transport mechanism. A second film forming step of forming a second sputtered film on the second surface of the substrate held by the substrate holder by sputtering, and a second transfer unit of the substrate holder transfer mechanism. Transporting the substrate holder along the transport path in the second transport direction, and subjecting the second sputtered film on the second surface of the substrate to vacuum annealing by the second vacuum annealing mechanism. And a second vacuum annealing process for performing the process.
The present invention is a method for manufacturing a solar cell using the film forming apparatus described above, wherein, as the substrate, an i-type amorphous silicon layer and a p-type amorphous silicon layer are provided on a first surface of an n-type crystalline silicon substrate. A substrate is provided in which an i-type amorphous silicon layer and an n-type amorphous silicon layer are sequentially provided on a second surface of the n-type crystalline silicon substrate, and a first transfer of the substrate holder transfer mechanism is performed. Transporting the substrate holder in the first transport direction along the transport path so as to pass through the first film formation region by the unit, and on the first surface of the substrate held by the substrate holder. Forming a first transparent conductive oxide film in an amorphous state by sputtering, and moving the substrate holder along the transport path by a first transport unit of the substrate holder transport mechanism. A first transfer unit that transfers the substrate in the first transfer direction and performs a vacuum annealing process on the first transparent conductive oxide film in an amorphous state on the first surface of the substrate by the first vacuum annealing mechanism; A vacuum annealing process and a process in which the substrate holder is moved up and down from the first transport unit to the second transport unit along the transport path while maintaining the vertical relationship of the substrate holder by the transport turn-back unit of the substrate holder transport mechanism. And transporting the substrate holder by the second transport unit along the transport path so that the substrate holder passes through the second film formation region by the second transport unit of the substrate holder transport mechanism. Forming a second transparent conductive oxide film in an amorphous state by sputtering on a second surface of the substrate held by the substrate holder, and a second step of the substrate holder transfer mechanism. The transport unit transports the substrate holder in the second transport direction along the transport path, and moves the second transparent conductive oxide film on the second surface of the substrate in the amorphous state to the second transparent conductive oxide film. And a second vacuum annealing treatment step of performing a vacuum annealing treatment by the vacuum annealing treatment mechanism of (1).
The present invention is a method for manufacturing a solar cell using the film forming apparatus described above, wherein, as the substrate, an i-type amorphous silicon layer and a p-type amorphous silicon layer are provided on a first surface of an n-type crystalline silicon substrate. A substrate is provided in which an i-type amorphous silicon layer and an n-type amorphous silicon layer are sequentially provided on a second surface of the n-type crystalline silicon substrate, and a first transfer of the substrate holder transfer mechanism is performed. Transporting the substrate holder in the first transport direction along the transport path so as to pass through the first film formation region by the unit, and on the first surface of the substrate held by the substrate holder. Forming a first transparent conductive oxide film in an amorphous state by sputtering, and moving the substrate holder along the transport path by a first transport unit of the substrate holder transport mechanism. A first transfer unit that transfers the substrate in the first transfer direction and performs a vacuum annealing process on the first transparent conductive oxide film in an amorphous state on the first surface of the substrate by the first vacuum annealing mechanism; A vacuum annealing process and a process in which the substrate holder is moved up and down from the first transport unit to the second transport unit along the transport path while maintaining the vertical relationship of the substrate holder by the transport turn-back unit of the substrate holder transport mechanism. And transporting the substrate holder in the second transport direction along the transport path by the second transport unit of the substrate holder transport mechanism, and the first vacuum annealing mechanism The first transparent conductive oxide film on the first surface of the substrate, which has been subjected to vacuum annealing by the above, is further subjected to vacuum annealing by the annealing promoting vacuum annealing mechanism. And promoting the substrate holder by the second transport unit of the substrate holder transport mechanism in the second transport direction along the transport path so as to pass through the second film formation region. Forming a second transparent conductive oxide film in an amorphous state by sputtering on a second surface of the substrate held by the substrate holder, and forming the second transparent conductive oxide film in an amorphous state by a second transfer unit of the substrate holder transfer mechanism. The substrate holder is transported along the transport path in the second transport direction, and the second transparent conductive oxide film on the second surface of the substrate is vacuumed by the second vacuum annealing mechanism. And a second vacuum annealing process for performing an annealing process.

  According to the present invention, a first vacuum annealing process is performed on a first sputtered film (for example, a first transparent conductive oxide film) in an amorphous state formed on a first surface of a substrate in a vacuum. In addition, since the second vacuum annealing process is performed on the amorphous second sputtered film (for example, the second transparent conductive oxide film) formed on the second surface of the substrate, The mobility of carriers can be improved by enlarging the crystal grains of, for example, the first and second transparent conductive oxide films in a crystalline state. A uniform transparent conductive oxide film of high quality can be formed, and crystallization progresses faster in vacuum annealing than in air, improving the efficiency of film formation and annealing. It can be.

  In this case, after performing the first vacuum annealing process on the first sputtered film on the first surface of the substrate and before forming the second sputtered film in an amorphous state on the second surface of the substrate, By further performing a vacuum annealing process on the first sputtered film on the first surface of the substrate, it is possible to promote the progress of crystallization of the first sputtered film in an amorphous state in which crystallization has progressed to some extent. This makes it possible to improve the mobility of carriers of the first sputtered film in a crystalline state on the first surface of the substrate. It is possible to form a transparent conductive oxide film in a crystalline state.

Schematic configuration diagram showing the entire embodiment of a film forming apparatus according to the present invention (A) and (b): Basic structures of a substrate holder transport mechanism and a direction change mechanism in the present embodiment, wherein FIG. 2 (a) is a plan view and FIG. 2 (b) is a front view. FIGS. 3A and 3B show the configuration of the substrate holder used in the present embodiment, where FIG. 3A is a plan view and FIG. 3B is a side view. Front view showing the configuration of the direction change mechanism in the present embodiment. (A) to (d): cross-sectional process diagrams illustrating a method for forming a transparent conductive oxide film in this embodiment. Explanatory drawing showing the operation of the film forming apparatus of the present embodiment (part 1) Explanatory drawing showing the operation of the film forming apparatus of the present embodiment (part 2) Explanatory drawing showing the operation of the film forming apparatus of the present embodiment (part 3) (A) and (b): Explanatory diagrams showing the operation of the substrate holder transport mechanism in the present embodiment (part 1) (A) to (c): Explanatory diagrams (part 1) showing the operations of the substrate holder transport mechanism and the direction changing mechanism in the present embodiment. (A) to (c): Explanatory diagrams showing the operations of the substrate holder transport mechanism and the direction changing mechanism in the present embodiment (part 2) (A) and (b): Explanatory diagrams showing the operation of the substrate holder transport mechanism in the present embodiment (part 3) Explanatory drawing showing the operation of the film forming apparatus of the present embodiment (part 4) Explanatory drawing showing the operation of the film forming apparatus of the present embodiment (part 5) Explanatory drawing showing the operation of the film forming apparatus of the present embodiment (part 6) Front view showing the configuration of another example of the direction change mechanism (A)-(c): Explanatory drawing (1) which shows operation | movement of the other example of a board | substrate holder conveyance mechanism and a direction change mechanism. (A)-(c): Explanatory drawing (2) which shows operation | movement of the other example of a board | substrate holder conveyance mechanism and a direction change mechanism. Sectional view showing a schematic configuration of a general heterojunction solar cell (A) and (b): SEM photographs showing the surface and cross section of the indium oxide film of the example. (A) and (b): SEM photographs showing the surface and cross section of the indium oxide film of the comparative example.

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

  FIG. 1 is a schematic configuration diagram showing an entire embodiment of a film forming apparatus according to the present invention.

  FIGS. 2A and 2B show the basic structure of the substrate holder transport mechanism and the direction changing mechanism in the present embodiment. FIG. 2A is a plan view, and FIG. FIG.

  3 (a) and 3 (b) show the configuration of the substrate holder used in the present embodiment. FIG. 3 (a) is a plan view and FIG. 3 (b) is a side view.

  FIG. 4 is a front view showing the configuration of the direction changing mechanism in the present embodiment.

  As shown in FIG. 1, the film forming apparatus 1 according to the present embodiment has a vacuum chamber 2 connected to a vacuum pumping apparatus 1a having, for example, a turbo molecular pump, in which a single vacuum atmosphere is formed. .

  A substrate holder transport mechanism 3 that transports a substrate holder 11 described below along a transport path is provided inside the vacuum chamber 2.

  The substrate holder transport mechanism 3 is configured to continuously transport a plurality of substrate holders 11 that hold a substrate 10.

  Here, the substrate holder transport mechanism 3 includes first and second circular drive wheels 31 and 32 having the same diameter and operating by transmitting a rotational driving force from a drive mechanism (not shown) made of, for example, a sprocket or the like. The first and second drive wheels 31 and 32 are arranged at a predetermined distance in a state where their rotation axes are parallel to each other.

  A series of transport drive members 33, for example, composed of a chain or the like are bridged between the first and second drive wheels 31, 32.

  Further, a structure in which a transport drive member 33 is bridged between the first and second drive wheels 31 and 32 is arranged in parallel at a predetermined distance (see FIG. 2A), and the pair of transports is provided. The drive member 33 forms a series of annular transport paths with respect to the vertical plane.

  In the present embodiment, the substrate holder 11 is moved from the first drive wheel 31 toward the second drive wheel 32 to the upper portion of the transport drive member 33 constituting the transport path to move the substrate holder 11 to the first transport wheel. A forward transport section (first transport section) 33a for transporting in the direction P1 is formed, and the transport direction of the substrate holder 11 is reversed by the transport drive member 33 around the second drive wheel 32. A return portion 33b that changes the direction is formed, and further, the lower portion of the transport drive member 33 is moved from the second drive wheel 32 toward the first drive wheel 31 to move the substrate holder 11 to the first position. A return-side transport section (second transport section) 33c that transports the sheet in the second transport direction P2 is formed.

  In the substrate holder transport mechanism 3 of the present embodiment, a forward transport section 33a located above each transport drive member 33 and a return transport section 33c located below each transport drive member 33 face each other. In addition, they are configured to overlap in the vertical direction.

  Further, the substrate holder transport mechanism 3 includes a substrate holder introduction part 30A for introducing the substrate holder 11, a transport return part 30B for returning the substrate holder 11 and transporting the same, and a substrate holder for discharging the substrate holder 11. A container discharge unit 30C is provided.

  Here, a direction changing mechanism 40, which will be described later, is provided in the vicinity of the transport turn-back portion 30B.

  First and second film formation regions 4 and 5 are provided in the vacuum chamber 2.

  In the present embodiment, a first film formation region 4 having a first sputtering source 4T is provided, for example, above the substrate holder transport mechanism 3 in the vacuum chamber 2, and the substrate holder transport mechanism 3, for example, is provided. A second film formation region 5 having a second sputtering source 5T is provided below.

  In the present embodiment, the outward transport section 33a of the transport driving member 33 described above is configured to pass straight through the first film formation region 4 in the horizontal direction, and the return transport section 33c is It is configured to pass straight through the second film formation region 5 in the horizontal direction.

  Then, when the substrate holder 11 passes through the forward-side transport portion 33a and the backward-side transport portion 33c of the transport drive member 33 constituting the transport path, the plurality of substrates 10 (FIG. (See (a)) is conveyed in a horizontal state.

  As shown in FIG. 1, in the present embodiment, a first vacuum annealing mechanism 21 is provided near the first transport direction P1 side of the first film formation region 4 in the vacuum chamber 2. I have.

  Further, a second vacuum annealing mechanism 22 is provided near the second transport direction P2 side of the second film formation region 5 in the vacuum chamber 2.

  As the first and second vacuum annealing mechanisms 21 and 22, for example, a radiant (radiation) electric heater such as a sheath heater can be suitably used.

  Further, between the first and second film forming regions 4 and 5, for example, below the second drive wheel 32, an annealing accelerating vacuum annealing mechanism 23 is provided.

  As in the first and second vacuum annealing mechanisms 21 and 22, the radiating (radiation) electric heating type heater such as a sheath heater can be suitably used as the annealing promoting vacuum annealing mechanism 23.

  On the other hand, a cooling mechanism 25 is provided on the second transport direction P2 side of the annealing promoting vacuum annealing mechanism 23 and in the vicinity of the second transport area 5 on the first transport direction P1 side.

  As the cooling mechanism 25, for example, radiation (radiation) of a structure configured to cool copper having a good thermal conductivity using a cooling medium or a plate configured to circulate cooling water through a pipe through a metal plate is used. ) Method can be suitably used.

  A position for transferring and receiving the substrate holder 11 to and from the substrate holder transport mechanism 3 is provided at a position near the substrate holder transport mechanism 3 in the vacuum chamber 2, for example, at a position adjacent to the first drive wheel 31. A substrate loading / unloading mechanism 6 is provided.

  The substrate carry-in / carry-out mechanism 6 of the present embodiment has a support part 62 provided at the tip (upper) end of a drive rod 61 driven vertically by, for example, a vertical mechanism.

  In the present embodiment, the transfer robot 64 is provided on the support portion 62 of the substrate loading / unloading mechanism 6, and supports the above-described substrate holder 11 on the transfer robot 64 to move the substrate holder 11 in the vertical and vertical directions. The transfer robot 64 is configured to transfer and receive the substrate holder 11 to and from the substrate holder transport mechanism 3.

  In this case, as described later, the substrate holder 11 is transferred from the substrate loading / unloading mechanism 6 to the substrate holder introduction section 30A of the forward-side transport section 33a of the substrate holder transport mechanism 3 (this position is referred to as a “substrate holder transfer position”). ), And the substrate holder 11 is taken out from the substrate holder ejecting section 30C of the return-side transfer section 33c of the substrate holder transfer mechanism 3 (this position is referred to as a “substrate holder take-out position”). Have been.

  A substrate loading / unloading chamber 2 </ b> A for loading the substrate 10 into the vacuum chamber 2 and unloading the substrate 10 from the vacuum chamber 2 is provided, for example, above the vacuum chamber 2.

  The substrate loading / unloading chamber 2A is provided, for example, at a position above the support section 62 of the above-described substrate loading / unloading mechanism 6 via the communication port 2B. A lid 2a is provided.

  Then, as described later, the substrate 10a before film formation carried into the substrate carry-in / carry-out chamber 2A is delivered to and held by the substrate holder 11 on the transfer robot 64 of the support portion 62 of the substrate carry-in / carry-out mechanism 6, and The substrate 10b after film formation is configured to be carried out from the substrate holder 11 on the transfer robot 64 of the support portion 62 of the substrate carry-in / carry-out mechanism 6 into, for example, the atmosphere outside the vacuum chamber 2.

  In the case of the present embodiment, the substrate loading / unloading chamber 2A is isolated from the atmosphere in the vacuum chamber 2 when loading and unloading the substrate 10 at the upper edge of the support portion 62 of the substrate loading / unloading mechanism 6. For example, a seal member 63 such as an O-ring is provided.

  In this case, the supporting portion 62 of the substrate loading / unloading mechanism 6 is raised toward the substrate loading / unloading chamber 2A, and the seal member 63 on the supporting portion 62 is brought into close contact with the inner wall of the vacuum chamber 2 to close the communication port 2B. The atmosphere in the substrate loading / unloading chamber 2 </ b> A is configured to be isolated from the atmosphere in the vacuum chamber 2.

  As shown in FIGS. 2A and 2B, a plurality of first driving units 36 are provided at a predetermined interval between the pair of transport driving members 33 of the substrate holder transport mechanism 3 of the present embodiment. It is provided so as to protrude outward from the transport driving member 33.

  The first drive unit 36 is formed in, for example, a J-hook shape (a shape in which a groove is formed such that the height of the protrusion on the downstream side in the transport direction is lower than the height of the protrusion on the upstream side in the transport direction). To drive the substrate holder 11 in the first or second transport direction P1 or P2 by contacting the first driven shaft 12 of the substrate holder 11 supported by the substrate holder support mechanism 18 described later. It is configured to be.

  A pair of substrate holder supporting mechanisms 18 that support the substrate holder 11 to be transported are provided inside the pair of transport driving members 33.

  The substrate holder supporting mechanism 18 is composed of a rotatable member such as a plurality of rollers, for example, and is provided near the transport driving member 33, respectively.

  In the present embodiment, the forward-side substrate holder support mechanism 18a is provided near the forward path-side transport section 33a of the transport drive member 33, and the backward-path substrate is located near the downstream path-side transport section 33c of the transport drive member 33. A holder support mechanism 18c is provided, and is arranged and configured to support both edges of the lower surface of the substrate holder 11 to be conveyed.

  The forward-side substrate holder support mechanism 18a is provided up to the vicinity of the entrance of the first direction change path 51 of the later-described direction change mechanism 40, and the return-side substrate holder support mechanism 18c is provided with a later-described direction change mechanism. 40 is provided to the vicinity of the outlet of the second direction change path 52.

  The substrate holder 11 used in the present embodiment is for performing vacuum processing on both surfaces of the substrate 10 and is formed of a tray having an opening.

  As shown in FIGS. 2A and 3A, the substrate holder 11 of the present embodiment is formed in, for example, a long rectangular flat plate shape, and its longitudinal direction, that is, the first and second transport directions. A plurality of holding units 14 are provided for holding, for example, a plurality of rectangular substrates 10 in a row in a direction orthogonal to P1 and P2.

  Here, each holding unit 14 is provided with, for example, a rectangular opening having the same size and shape as each substrate 10 and both surfaces of each substrate 10 are entirely exposed. Is held horizontally.

  In the present invention, although not particularly limited, from the viewpoint of reducing the installation area and improving the processing capability, the substrate holder 11 may be moved in a direction orthogonal to the transport direction as in the present embodiment. It is preferable that a plurality of substrates 10 are arranged in a line and held respectively.

  However, from the viewpoint of improving processing efficiency, it is also possible to arrange a plurality of substrates 10 in a plurality of rows in a direction orthogonal to the transport direction.

  On the other hand, first driven shafts 12 are provided at both ends in the longitudinal direction of the substrate holder 11 on the upstream side in the first transport direction P1, respectively, and on the downstream side in the first transport direction P1. A second driven shaft 13 is provided at each end.

  Each of the first and second driven shafts 12 and 13 is formed in a circular cross section with a rotation axis extending in a direction orthogonal to the transport direction, that is, a longitudinal direction of the substrate holder 11 as a center.

  In the present embodiment, the size is determined such that the length of the second driven shaft 13 is longer than the length of the first driven shaft 12.

  Specifically, as shown in FIG. 2A, when the substrate holder 11 is disposed on the substrate holder transport mechanism 3, the first driven shafts 12 on both sides of the substrate holder 11 are connected to the substrate holder. When the substrate holder 11 is in contact with the first driving unit 36 of the transport mechanism 3 and the substrate holder 11 is disposed on the direction changing mechanism 40 described below, the second driven shaft 13 contacts the second driving unit 46 described later. The dimensions of the first and second driven shafts 12 and 13 are determined in such a manner.

  A pair of direction change mechanisms 40 having the same configuration are provided downstream of the pair of transport driving members 33 in the first transport direction P1.

  In the case of the present embodiment, the pair of direction change mechanisms 40 are disposed outside the pair of transport driving members 33 in the first and second transport directions P1 and P2, respectively.

  In addition, the pair of direction change mechanisms 40 are provided such that an upstream portion in the first transport direction P1 slightly overlaps a downstream portion of each transport drive member 33 in the first transport direction P1. .

  As shown in FIG. 4, the direction changing mechanism 40 of the present embodiment has a first guide member 41, a second guide member 42, and a third guide member 43, and these first to third guide members are provided. The members 41 to 43 are arranged in this order from the upstream side in the first transport direction P1.

  In the present embodiment, the first to third guide members 41 to 43 are respectively disposed at positions near the outside of the pair of transport driving members 33, and further, the outside of the first to third guide members 41 to 43. At a nearby position, a transport driving member 45 described later is arranged.

  In FIG. 2B, a part of the direction changing mechanism 40 is omitted, and the positional relationship between the members in the transport direction is shown ignoring the overlapping relationship of the members.

  As shown in FIGS. 2A and 4, the first to third guide members 41 to 43 are made of, for example, plate-like members, and are provided in the vertical direction, respectively.

  Here, the portion of the first guide member 41 on the first transport direction P1 side is formed in a curved shape that is convex toward the first transport direction P1 side, and the second guide member 42 has the second surface. The portion on the transport direction P2 side is formed in a curved shape that is concave on the first transport direction P1 side.

  The first and second guide members 41 and 42 have a curved surface in which a portion of the first guide member 41 on the first transport direction P1 side and a portion of the second guide member 42 on the second transport direction P2 side are equivalent. These parts are arranged close to each other with a gap slightly larger than the diameter of the first driven shaft 12 of the substrate holder 11. A first direction change path 51 that guides the first driven shaft 12 of the substrate holder 11 through the gap is provided.

  Further, the portion of the second guide member 42 on the first transport direction P1 side is formed in a curved shape that is convex toward the first transport direction P1 side, and the second transport of the third guide member 43 is The portion on the direction P2 side is formed in a curved shape concave toward the first transport direction P1 side.

  The second and third guide members 42 and 43 have a curved surface in which a portion of the second guide member 42 on the first transport direction P1 side and a portion of the third guide member 43 on the second transport direction P2 side are equivalent. These portions are arranged close to each other with a gap slightly larger than the diameter of the second driven shaft 13 of the substrate holder 11. Then, a second direction change path 52 for guiding the second driven shaft 13 of the substrate holder 11 through the gap is provided.

  In the present embodiment, the first direction change path 51 and the second direction change path 52 are formed in the same curved shape.

  Furthermore, the distance in the horizontal direction of each part of the first and second direction change paths 51 and 52 is equal to the distance between the first and second driven shafts 12 and 13 of the substrate holder 11. The dimensions are determined as follows.

  Further, in the present embodiment, the upper opening of the first direction change path 51 is the entrance of the first driven shaft 12 of the substrate holder 11, and the height position of the opening is The substrate holder 11 supported by the holder support mechanism 18a is configured to be at a position lower than the height position of the second driven shaft 13 (see FIG. 2B).

  Further, the opening on the lower side of the first direction change path 51 is an outlet of the first driven shaft 12 of the substrate holder 11, and the height position thereof is determined by the return-side substrate holder support mechanism 18c. (See FIG. 2 (b)). The substrate holder 11 is supported at a position higher than the height of the second driven shaft 13.

  In the second direction changing path 52, the upper opening is an entrance of the second driven shaft 13 of the substrate holder 11, and the height position of the opening is the forward path side substrate holder support. The substrate holder 11 supported by the mechanism 18a is configured to be at a position equivalent to the height position of the second driven shaft 13 (see FIG. 2B).

  On the other hand, the opening on the lower side of the second direction change path 52 is an outlet of the second driven shaft 13 of the substrate holder 11, and its height position is determined by the return-side substrate holder support mechanism 18c. (See FIG. 2B) so as to be at a position equivalent to the height position of the second driven shaft 13 of the substrate holder 11 supported by the substrate holder 11.

  The direction changing mechanism 40 according to the present embodiment includes, for example, a pair of sprockets, and a transport driving member 45 composed of a chain spanned over the pair of sprockets. It is configured to be annular.

  The transport drive member 45 is configured such that the radius of curvature of the folded portion is equal to the radius of curvature of the folded portion 33b of the transport drive member 33 of the substrate holder transport mechanism 3.

  The transport driving member 45 is driven such that the upper portion moves in the first transport direction P1 and the lower portion moves in the second transport direction P2.

  The transport drive member 45 is provided with a plurality of second drive units 46 at predetermined intervals so as to protrude outward from the transport drive member 45.

  The second driving unit 46 has a concave portion formed in a portion on the outer side of the transport driving member 45, and the edge of the concave portion contacts the second driven shaft 13 of the substrate holder 11, and 11 is configured to be supported and driven along the second direction change path 52.

  In addition, as described later, when the second driving section 46 of the present embodiment has reached the positions of the entrance and the exit of the second direction change path 52, its end on the concave side is the second direction. The path of the transport drive member 45 and the dimensions of the second drive unit 46 are set so as to retreat from the direction change path 52 (see FIG. 2B).

  In the present embodiment, as will be described later, the transport drive member 33 of the substrate holder transport mechanism 3 operates such that the second driver 46 operates in synchronization with the first driver 36 of the substrate holder transport mechanism 3. And the operation of the transport driving member 45 of the direction changing mechanism 40 is controlled.

  In the present embodiment, the substrate holder 11 is driven in the first transport direction P1 by the first drive unit 36 of the substrate holder transport mechanism 3 to move the first and second driven shafts 12 and 13. When the substrate holder 11 enters the first and second direction change paths 51 and 52, the first and second driving units 36 and 46 maintain the vertical relationship of the substrate holder 11, and the first and second driving units 36 and 46 respectively. The first and second driving units 36 and 46, and the first and second driving units 36 and 46 so that the driving shafts 12 and 13 are supported and move, and are smoothly discharged from the first and second turning paths 51 and 52. The shapes and dimensions of the second direction change paths 51 and 52 are respectively set.

  On the other hand, below the first guide member 41 and the second guide member 42 and near the discharge port of the first direction changing path 51, the substrate holder 11 is moved from the direction changing mechanism 40 to the substrate holder supporting mechanism 18. A delivery member 47 is provided for smoothly delivering the substrate to the return-side substrate holder support mechanism 18c.

  The transfer member 47 is formed of, for example, an elongated member extending in the horizontal direction. The transfer member 47 is centered on a rotation shaft 48 provided at a position below the return-side substrate holder support mechanism 18c at an end on the second transport direction P2 side. It is configured to rotate vertically. The portion of the transfer member 47 on the first transport direction P1 side is urged upward by, for example, an elastic member (not shown).

  The elastic member used in the present invention is not particularly limited, but from the viewpoint of reliably preventing buckling without increasing the number of parts, a torsion coil spring is used rather than a coil spring (for example, a compression coil spring). Is preferred.

  In the upper part of the transfer member 47, a portion adjacent to the discharge port of the first direction changing path 51 on the second transport direction P2 side is continuous with the first direction changing path 51 and has a substrate holder supporting mechanism. A transfer portion 47a having a curved shape is provided so as to be continuous with the return-side substrate holder support mechanism 18c of FIG. 18 (see FIG. 2B).

  In the upper part of the transfer member 47, an inclined surface 47b that is inclined downward toward the first transport direction P1 is provided at a portion on the first transport direction P1 side. The inclined surface 47b is provided at a height position facing the discharge port of the second direction change path 52.

  Hereinafter, an operation of the film forming apparatus 1 and an example of a film forming method of the present embodiment will be described with reference to FIGS. 5 (a) to 5 (d) to FIG.

  5A to 5D are cross-sectional process diagrams illustrating a method for forming a transparent conductive oxide film in the present embodiment.

  As shown in FIG. 5A, the substrate 10a before film formation used in the present embodiment is formed on the first surface (the upper surface, which is the light receiving surface in the present embodiment) of the n-type crystalline silicon substrate 10A. A-type amorphous silicon layer 10B and a first conductivity type (for example, p-type) amorphous silicon layer 10D are sequentially provided, and the second surface of the n-type crystal silicon substrate 10A (the lower surface which is the reflection surface side in this embodiment). An i-type amorphous silicon layer 10C and a second conductivity type (for example, n-type) amorphous silicon layer 10E are sequentially provided thereon.

  In the present embodiment, first, the sealing member 63 on the support portion 62 of the substrate loading / unloading mechanism 6 is brought into close contact with the inner wall of the vacuum tank 2 to reduce the atmosphere in the substrate loading / unloading chamber 2A with respect to the atmosphere in the vacuum tank 2. After venting to atmospheric pressure in the isolated state, as shown in FIG. 6, the lid 2a of the substrate loading / unloading chamber 2A is opened.

  Thereafter, the substrate 10a before film formation is mounted and held on the substrate holder 11 on the transfer robot 64 of the support portion 62 of the substrate carry-in / carry-out mechanism 6 using a transfer robot (not shown).

  Then, after closing the lid 2a of the substrate loading / unloading chamber 2A and evacuating it to a predetermined pressure, as shown in FIG. 7, the supporting portion 62 of the substrate loading / unloading mechanism 6 is moved to the above-described substrate holder transfer position. The substrate holder 11 is lowered so that the height of the substrate holder 11 is equal to the height position of the forward-side transport section 33 a of the transport drive member 33.

  Further, as shown in FIG. 8, the substrate holder 11 is arranged in the substrate holder introduction portion 30A of the substrate holder transport mechanism 3 by the transport robot 64 provided on the support portion 62 of the substrate loading / unloading mechanism 6.

  In this case, as shown in FIG. 9A, the first driven shaft 12 of the substrate holder 11 is positioned so as to be disposed in the groove of the first drive unit 36, and the forward-side substrate holder is supported. It is placed on the mechanism 18a.

  In this state, as shown in FIG. 9B, the forward-side transport section 33a of the transport drive member 33 of the substrate holder transport mechanism 3 is moved in the first transport direction P1.

  Thus, the first driven shaft 12 of the substrate holder 11 is driven in the first transport direction P1 by the first drive unit 36 on the forward transport unit 33a of the transport drive member 33, and the substrate holder 11 is moved. The sheet is transported on the forward transport section 33a of the transport drive member 33 toward the transport turning section 30B.

  In this operation, the first surface (upper surface) of the substrate 10 a before film formation held by the substrate holder 11 is positioned above the substrate holder 11 when passing through the first film formation region 4. The first sputtering source 4T performs film formation by sputtering.

  Specifically, as shown in FIG. 5B, for example, an n-type first transparent conductive oxide film (the first transparent conductive oxide film) is formed on the surface of the p-type amorphous silicon layer 10D of the substrate 10a before film formation by sputtering. A sputtered film 10f is entirely formed. At this point, the first transparent conductive oxide film 10f is a film in an amorphous state.

  In the case of the present invention, the material of the first transparent conductive oxide film 10f is not particularly limited, but it is preferable to use an indium oxide-based material which is a low-resistance and light-transmitting material, and more preferably. Is a material in which at least one or more metal oxides such as titanium oxide, zirconium oxide, tungsten oxide, cerium oxide, gallium oxide, and silicon oxide are added to indium oxide in trace amounts.

  After this film formation, before the substrate holder 11 arrives at the transport turn-back portion 30B of the substrate holder transport mechanism 3, the first vacuum annealing processing mechanism 21 (see FIG. 1) described above makes the first transparent amorphous state transparent. The first vacuum annealing treatment is performed by heating the conductive oxide film 10f.

  In this case, it is preferable to set the heating conditions so as to be 180 ° C. or more and 220 ° C. or less.

  FIGS. 10A to 10C and FIGS. 11A to 11C are explanatory views showing the operations of the substrate holder transport mechanism and the direction changing mechanism in the present embodiment.

  In the present embodiment, after the above-described film forming process, by moving the first drive unit 36 of the substrate holder transport mechanism 3 in the first transport direction P1, as shown in FIG. The substrate holder 11 that has reached the transfer folding portion 30B of the substrate holder transfer mechanism 3 is further moved in the first transfer direction P1, and the second driven shaft 13 of the substrate holder 11 is moved to the second position of the direction change mechanism 40. At the entrance of the direction change path 52.

  In this case, the operation of the transport driving member 45 is controlled such that the second driving section 46 of the direction changing mechanism 40 is located below the second driven shaft 13 of the substrate holder 11.

  Then, the transport drive member 33 of the substrate holder transport mechanism 3 is driven to move the first drive unit 36 in the first transport direction P1, and the transport drive member 45 of the direction change mechanism 40 is driven to drive the Is moved in the first transport direction P1. In this case, control is performed such that the operations of the first drive unit 36 and the second drive unit 46 are synchronized.

  Thereby, as shown in FIG. 10B, the first and second driven shafts 12 and 13 of the substrate holder 11 are supported and driven by the first and second driving units 36 and 46, respectively, and And move downward in the second direction changing paths 51 and 52, respectively.

  In this process, the first driven shaft 12 of the substrate holder 11 does not contact the first direction changing path 51 at the same time, but the first guide member 41 and the second guide member 42 The second driven shaft 13 does not contact at the same time in the second turning path 52, but also contacts the edge of the second guide member 42 and the third guide member 43. Although they make contact, the substrate holder 11 maintains the vertical relationship.

  Then, from the vicinity where the first and second driven shafts 12 and 13 pass through the middle portions of the first and second direction change paths 51 and 52, respectively, the first and second driven shafts 12 and 13 The transport direction is changed to a second transport direction P2 opposite to the first transport direction P1 while maintaining the vertical relationship of the substrate holder 11.

  In this process, the first driven shaft 12 of the substrate holder 11 does not contact the first direction changing path 51 at the same time, but the first guide member 41 and the second guide member 42 The second driven shaft 13 does not contact at the same time in the second turning path 52, but also contacts the edge of the second guide member 42 and the third guide member 43. Contact.

  Further, when the drive of the transport drive member 33 of the substrate holder transport mechanism 3 and the drive of the transport drive member 45 of the direction change mechanism 40 are continued, the first driven shaft of the substrate holder 11 is moved as shown in FIG. 12 is disposed above the transfer member 47 via the discharge port of the first direction change path 51 and the transfer portion 47a of the transfer member 47, and the second driven shaft 13 of the substrate holder 11 is The substrate holder 11 is disposed at the position of the discharge port of the second direction change path 52, and then, as shown in FIG. 11A, the substrate holder 11 is connected to the return-side substrate holder support mechanism 18 c of the substrate holder support mechanism 18. Handed over.

  At the time shown in FIG. 10C, the second driving unit 46 of the direction changing mechanism 40 and the second driven shaft 13 of the substrate holder 11 are not in contact, and the substrate holder 11 The first transport unit 36 of the container transport mechanism 3 is driven in contact with the first driven shaft 12 to move in the second transport direction P2.

  Then, by further driving of the transport driving member 33 of the substrate holder transport mechanism 3, the second driven shaft 13 of the substrate holder 11 is moved to the inclined surface 47 b of the transfer member 47 as shown in FIG. Upon contact, the transfer member 47 rotates downward around the rotation shaft 48, and the second driven shaft 13 of the substrate holder 11 passes above the transfer member 47 as shown in FIG. Then, the substrate holder 11 moves in the second transport direction P2.

  After this process, the transfer member 47 returns to the original position by the urging force of an elastic member (not shown).

  Thereafter, as shown in FIG. 12A, the backward transport portion 33c of the transport drive member 33 of the substrate holder transport mechanism 3 is moved in the second transport direction P2, and the first drive portion 36 is moved in the same direction. By driving, the substrate holder 11 is transported toward the substrate holder discharge unit 30C.

  In this case, since the temperature of the substrate 10a before film formation decreases when passing through the direction changing mechanism 40, when the substrate holder 11 is transported toward the substrate holder discharge unit 30C, the substrate holder The second surface (lower surface) of the substrate 10a before film formation held by the substrate 11 is heated by the above-described vacuum accelerating mechanism for accelerating annealing 23 (see FIG. 1) to form the first transparent conductive oxide film in an amorphous state. 10f is further heated to perform a vacuum annealing process.

  In this case, it is preferable to set the heating conditions so as to be 180 ° C. or more and 220 ° C. or less. Then, the progress of crystallization of the transparent conductive oxide film 10f is promoted by this annealing treatment. The total time of the first vacuum annealing process and the annealing process for annealing promotion is about several minutes.

  Then, in order to prevent the substrate temperature from excessively rising, the substrate 10a is cooled by the cooling mechanism 25 (see FIG. 1) as necessary.

  Thereafter, when passing through the second film formation region 5 shown in FIG. 1, the substrate is held on the surface of the n-type amorphous silicon layer 10 </ b> E on the second surface (lower surface) of the substrate 10 a held by the substrate holder 11. For example, an n-type second transparent conductive oxide film (second sputtered film) 10g is entirely formed by sputtering by a second sputter source 5T located below the vessel 11 (see FIG. 5C). . At this point, the second transparent conductive oxide film 10g is an amorphous film.

  When forming the second transparent conductive oxide film 10g, a mask (not shown) is used to prevent a short circuit with the first transparent conductive oxide film 10f formed on the first surface of the substrate 10a. It is preferable to form the first transparent conductive oxide film 10f such that the edge of the first transparent conductive oxide film 10f is located slightly inward with respect to the edge of the substrate 10a.

  In the case of the present invention, the material of the second transparent conductive oxide film 10g is not particularly limited, but similarly to the above-described first transparent conductive oxide film 10f, a low-resistance and light-transmitting material is used. It is preferable to use an indium oxide-based material. More preferably, a trace amount of at least one metal oxide such as titanium oxide, zirconium oxide, tungsten oxide, cerium oxide, gallium oxide, and silicon oxide is added to indium oxide. It was done.

  In the present embodiment, when the second transparent conductive oxide film 10 g in the amorphous state is formed by sputtering, the amorphous state in which crystallization has progressed to some extent on the first surface of the substrate 10 a by the heat of the plasma due to the discharge. The crystallization of the first transparent conductive oxide film 10f further proceeds and is almost completed. Then, as shown in FIG. 5C, the first transparent conductive oxide film 10F in a crystalline state is formed.

  Furthermore, in the present embodiment, after the above-described film formation, before the substrate holder 11 reaches the substrate holder discharge unit 30C of the substrate holder transport mechanism 3, the second vacuum annealing mechanism 22 (FIG. 1), the second transparent conductive oxide film 10g in an amorphous state is heated to perform vacuum annealing.

  In this case, it is preferable to set the heating conditions so as to be 180 ° C. or more and 220 ° C. or less.

  By this second annealing, the second transparent conductive oxide film 10g in an amorphous state is crystallized to form a second transparent conductive oxide film 10G in a crystalline state. As a result, as shown in FIG. Then, the substrate 10b after film formation is obtained.

  Then, after the substrate holder 11 that moves in the second transport direction P2 reaches the substrate holder discharge unit 30C, the backward transport unit 33c of the transport driving member 33 is moved in the second transport direction P2, and the first transport direction is performed. When the drive unit 36 is driven in the same direction, the first drive unit 36 is inclined from the vertical direction with the movement of the return-side transport unit 33c, as shown in FIG. The contact between the driving unit 36 and the first driven shaft 12 is released, whereby the substrate holder 11 loses the propulsive force. Therefore, the substrate holding unit 11 is moved by the transfer robot 64 of the substrate loading / unloading mechanism 6 shown in FIG. Is moved in the second transport direction P <b> 2 to be separated from the first drive unit 36.

  Further, the substrate holding device 11 is taken out using the transfer robot 64 of the substrate loading / unloading mechanism 6, and the substrate holder 11 is arranged on the support portion 62 together with the transfer robot 64 as shown in FIG.

  Thereafter, as shown in FIG. 14, the support portion 62 of the substrate loading / unloading mechanism 6 is raised, and the sealing member 63 on the support portion 62 is brought into close contact with the inner wall of the vacuum tank 2, and the substrate Vent to atmospheric pressure with the atmosphere in the loading / unloading chamber 2A isolated.

  Then, as shown in FIG. 15, the lid 2a of the substrate loading / unloading chamber 2A is opened, and the substrate 10b after film formation is taken out of the substrate holder 11 into the atmosphere using a transfer robot (not shown).

  Thereafter, returning to the state shown in FIG. 6, the above-described operation is repeated to perform the above-described film formation and annealing on both surfaces of each of the plurality of substrates 10a before film formation.

  The surface electrode of the heterojunction solar cell can be formed by applying, for example, a silver paste by screen printing on the first and second transparent conductive oxide films 10F and 10G in the above-described crystalline state, and by firing. it can.

  In the present embodiment described above, in vacuum, the first vacuum is applied to the amorphous first transparent conductive oxide film 10f formed on the first surface of the substrate 10a before film formation. Since the second vacuum annealing process is performed on the second transparent conductive oxide film 10g in an amorphous state formed on the second surface of the substrate 10a while performing the annealing process, The mobility of carriers can be improved by enlarging the crystal grains of the first and second transparent conductive oxide films 10F and 10G in the crystalline state. Since a high-quality and uniform transparent conductive oxide film can be formed on both sides, and crystallization proceeds at a higher speed in vacuum annealing than in air, the film formation and annealing are performed. It is possible to improve the efficiency of the process.

  In this case, after performing a first vacuum annealing process on the first transparent conductive oxide film 10f on the first surface of the substrate 10a, a second amorphous state is formed on the second surface of the substrate 10a. Before the transparent conductive oxide film 10g is formed, the first transparent conductive oxide film 10f in an amorphous state on the first surface of the substrate 10a may be further subjected to vacuum annealing treatment. Can promote the crystallization of the transparent conductive oxide film 10f, thereby further improving the carrier mobility of the crystalline first transparent conductive oxide film 10F on the first surface of the substrate 10a. Therefore, for example, a high-quality and uniform transparent conductive oxide film can be formed on the light receiving surface side of a substrate used for a heterojunction solar cell.

  FIG. 16 is a front view showing the configuration of another example of the direction changing mechanism.

  As shown in FIG. 16, the direction changing mechanism 40A of the present example has a transfer member 49 that replaces the transfer member 47 shown in FIG.

  The transfer member 49 is formed of, for example, an elongated member extending in the transport direction, and is provided near the discharge port of the first direction change path 51 of the direction change mechanism 40A and above the return path side substrate holder support mechanism 18c. The portion extending toward the second transport direction P2 around the shaft 49a is configured to rotate vertically.

  The transfer member 49 is formed such that a lower portion 49b is formed in a planar shape, and a tip portion 49c of the lower portion 49b on the second transport direction P2 side is inclined upward.

  The transfer member 49 is configured such that a portion on the second transport direction P2 side with respect to the rotation shaft 49a is slightly downwardly inclined with respect to the horizontal direction in a state where no external force is applied.

  In this case, the portion of the transfer member 49 on the second transport direction P2 side is urged downward by an elastic member such as a torsion coil spring (not shown) so that no external force acts on the portion on the second transport direction P2 side. The portion can be inclined slightly downward with respect to the horizontal direction, and the portion on the second transport direction P2 side with respect to the horizontal direction in a state where no external force acts due to the weight of the transfer member 49. It may be configured to be slightly inclined downward.

  FIGS. 17A to 17C and FIGS. 18A to 18C are explanatory views showing the operation of the substrate holder transport mechanism and the direction changing mechanism in this example.

  Also in this example, by moving the first driving unit 36 of the substrate holder transport mechanism 3 in the first transport direction P1, as shown in FIG. The substrate holder 11 that has reached the transport turn-back portion 30B of the transport mechanism 3 is further moved in the first transport direction P1, and the second driven shaft 13 of the substrate holder 11 is changed in the second direction by the direction changing mechanism 40A. It is disposed at the entrance of the path 52, and controls the operation of the transport driving member 45 so that the second driving section 46 of the direction changing mechanism 40A is located below the second driven shaft 13 of the substrate holder 11. I do.

  Then, the first driving unit 36 and the second driving unit 46 are moved in the first transport direction P1 in synchronization with each other, and as shown in FIG. And the second driven shafts 12 and 13 are supported and driven by the first and second driving units 36 and 46, respectively, and are moved downward in the first and second direction change paths 51 and 52, respectively. Thereby, the substrate holder 11 is moved downward while maintaining the vertical relationship.

  Then, from the vicinity where the first and second driven shafts 12 and 13 pass through the middle portions of the first and second direction change paths 51 and 52, respectively, the first and second driven shafts 12 and 13 The transport direction is changed to a second transport direction P2 opposite to the first transport direction P1 while maintaining the vertical relationship of the substrate holder 11.

  Further, when the drive of the transport drive member 33 of the substrate holder transport mechanism 3 and the drive of the transport drive member 45 of the direction changing mechanism 40A are continued, the first driven shaft of the substrate holder 11 is moved as shown in FIG. The second driven shaft 13 of the substrate holder 11 is disposed at the position of the discharge port of the second direction change path 52 while the 12 passes through the discharge port of the first direction change path 51 and the transfer member 49, Thereafter, as shown in FIG. 18A, the substrate holder 11 is transferred to the return-side substrate holder support mechanism 18c of the substrate holder support mechanism 18.

  At the time shown in FIG. 17C, the second driving portion 46 of the direction changing mechanism 40A and the second driven shaft 13 of the substrate holder 11 are not in contact with each other, and the substrate holder 11 The first transport unit 36 of the container transport mechanism 3 is driven in contact with the first driven shaft 12 to move in the second transport direction P2.

  Then, by further driving of the transport driving member 33 of the substrate holder transport mechanism 3, as shown in FIG. 18B, the second driven shaft 13 of the substrate holder 11 is moved to a lower portion of the transfer member 49. The transfer member 49 comes into contact with the transfer member 49b and rotates upward about the rotation shaft 49a. As shown in FIG. 18C, the second driven shaft 13 of the substrate holder 11 is moved to the distal end of the transfer member 49. The substrate holder 11 moves in the second transport direction P2 after passing below the portion 49c.

  After this process, the transfer member 49 returns to its original position by the urging force of an elastic member (not shown) or its own weight.

  According to the direction changing mechanism 40A having the transfer member 49 of the present embodiment described above, the frictional force when the substrate holder 11 passes through the transfer member 49 is minimized.

  Note that the present invention is not limited to the above-described embodiment, and various changes can be made.

  For example, in the above-described embodiment, a film forming apparatus having a transfer path formed such that a projection shape on a vertical plane is formed into a series of annular shapes has been described as an example. However, the present invention is not limited to this. The invention can also be applied to a so-called in-line type film forming apparatus having a path.

  In the above-described embodiment, the upper portion of the transport driving member 33 is the forward transport portion 33a, which is the first transport portion, and the lower portion of the transport driving member 33 is the second transport portion. Although the return-side transport unit 33c is a unit, the present invention is not limited to this, and the up-down relationship can be reversed.

  Further, in the above embodiment, the upper surface of the substrate is the first surface, and the lower surface is the second surface. However, the lower surface of the substrate may be the first surface, and the upper surface may be the second surface.

  Furthermore, in the above embodiment, the case where the transparent conductive oxide film is formed on both surfaces of the substrate for the heterojunction solar cell has been described as an example, but the present invention is not limited to this, and the present invention is not limited to this. It can be applied to the case where various films are formed thereon.

  However, the present invention is particularly effective when transparent conductive oxide films are formed on both surfaces of a substrate for a heterojunction solar cell.

  Further, in the above-described embodiment, the substrate holder transport mechanism 3 and the direction changing mechanism 40 are configured by a pair of sprockets and a chain bridged over the pair of sprockets. An annular transport drive mechanism can also be used.

  Further, the substrate holder supporting mechanism 18 may be configured using a belt or a rail instead of a roller.

  Furthermore, the present invention is not limited to the case where the substrate 10a before film formation is carried into the vacuum chamber 2 and the substrate 10b after film formation is carried out of the vacuum chamber 2 as in the above-described embodiment. The present invention can also be applied to a case where the substrate 10a is carried into the vacuum chamber 2 together with the substrate holder 11, and the substrate 10b after film formation is carried out from the vacuum chamber 2 together with the substrate holder 11.

  Hereinafter, embodiments of the present invention will be described.

<Example>
A film made of indium oxide (In ₂ O ₃ ) having a thickness of 110 nm was formed on a glass substrate by sputtering.
The sheet resistance of this indium oxide film was 42.9 Ω / □.

The indium oxide film was annealed at 200 ° C. for 5 minutes in a vacuum using a sheath heater.
Furthermore, the indium oxide film after the annealing treatment is immersed in phosphoric acid acetic acid (phosphoric acid 73: nitric acid 3: acetic acid 7: water 17) at a temperature of 40 ° C. for 70 seconds to perform half etching, and then the surface and the cross section are observed by SEM Was observed.
The results are shown in FIGS.

  The sheet resistance of the indium oxide film after the half etching was measured and found to be 44.0 Ω / □.

<Comparative example>
The sheet resistance of the indium oxide film formed by the same method as in the above example was measured and found to be 41.4 Ω / □.

Further, the indium oxide film was immersed in the above-mentioned phosphoric acid nitric acid at a temperature of 40 ° C. for 70 seconds to perform half etching, and then the surface and the cross section were observed by SEM.
The results are shown in FIGS.

  The sheet resistance of the indium oxide film after the half etching was measured and found to be 1518 Ω / □.

<Evaluation>
As shown in FIGS. 20 (a) and 20 (b), the indium oxide film of the example in which the vacuum annealing treatment was performed after the film formation had a uniform and dense surface and inside, and even after half-etching, The resistance value hardly increased.

  On the other hand, as shown in FIGS. 21A and 21B, the surface of the indium oxide film of the comparative example in which the vacuum annealing treatment was not performed after the film formation was formed in an island shape, and voids were formed inside. Many were seen.

  Furthermore, the sheet resistance of the indium oxide film of the comparative example was significantly increased (41.4Ω / □ → 1518Ω / □) after half-etching.

  From the above, it has been found that by performing the vacuum annealing treatment of the present invention, a uniform and high-quality sputtered film can be formed at the time when the film is discharged from the film forming apparatus.

DESCRIPTION OF SYMBOLS 1 ... Film-forming apparatus 2 ... Vacuum tank 3 ... Substrate holder conveyance mechanism 4 ... 1st film-forming area 4T ... 1st sputtering source 5 ... 2nd film-forming area 5T ... 2nd sputter source 6 ... Substrate carrying in Unloading mechanism 10 Substrate 10a Substrate 10b before film formation Substrate 10A after film formation n-type crystalline silicon substrate 10B, 10C ... i-type amorphous silicon layer 10D ... p-type amorphous silicon layer 10E ... n-type amorphous silicon layer 10f ... Amorphous first transparent conductive oxide film (amorphous first sputtered film)
10F: first transparent conductive oxide film in a crystalline state (first sputtered film in a crystalline state)
10g: A second transparent conductive oxide film in an amorphous state (a second sputtered film in an amorphous state)
10G: second transparent conductive oxide film in a crystalline state (second sputtered film in a crystalline state)
11 substrate holder 12 first driven shaft 13 second driven shaft 14 holding unit 18 substrate holder support mechanism 21 first vacuum annealing mechanism 22 second vacuum annealing mechanism 23 ... Vacuum annealing treatment mechanism 25 for promoting annealing 25 ... Cooling mechanism 30A ... Substrate holder introduction part 30B ... Transfer folding part 30C ... Substrate holder discharge part 33 ... Transport drive member (transport path)
33a: forward path transport section (first transport section)
33b ... return part 33c ... return-side transport unit (second transport unit)
40 direction changing mechanism P1 first transport direction P2 second transport direction

Claims (11)

A vacuum chamber capable of transporting the substrate along the transport path,
A first film formation region provided in the vacuum chamber and having a first sputtering source for forming a film on a first surface of the substrate;
A vacuum annealing process is performed on the first sputtered film in the amorphous state, which is provided on the downstream side in the transport direction of the first film formation region and formed on the first surface of the substrate in the first film formation region. A first vacuum annealing mechanism to be performed;
A second film formation region provided in the vacuum chamber and having a second sputtering source for forming a film on the second surface of the substrate;
A vacuum annealing process is performed on the second sputtered film in the amorphous state, which is provided on the downstream side in the transport direction of the second film formation region and is formed on the second surface of the substrate in the second film formation region. A second vacuum annealing mechanism for performing the process.   A first sputtered film on the first surface of the substrate that has been vacuum-annealed by the first vacuum annealing mechanism between the first vacuum annealing mechanism and the second film formation region. 2. The film forming apparatus according to claim 1, further comprising an annealing promoting vacuum annealing mechanism for performing a vacuum annealing process. A vacuum chamber in which a single vacuum atmosphere is formed;
A first film formation region provided in the vacuum chamber and having a first sputtering source for forming a film on the first surface of the substrate;
A second film formation region provided in the vacuum chamber and having a second sputtering source for forming a film on the second surface of the substrate;
A transport path formed so that the projected shape with respect to the vertical plane is formed into a series of annular shapes, and provided so as to pass through the first and second film formation regions;
A substrate holder having an opening through which the first and second surfaces of the substrate are exposed and holding the substrate in a horizontal state, a substrate holder transport mechanism for transporting the substrate along the transport path;
The substrate holder transport mechanism includes a first transport unit that transports the substrate holder in a first transport direction so as to pass through the first film formation area, and transports the substrate holder to the second component. A second transport unit that transports in a second transport direction opposite to the first transport direction so as to pass through the film region, and a first transport unit that maintains the substrate holder in an up-down relationship. Having a transport turn-back portion for returning and transporting toward the second transport portion,
A vacuum annealing process is performed on the first sputtered film in an amorphous state formed on the first surface of the substrate on the downstream side in the transport direction of the first film formation region of the first transport unit. Vacuum annealing mechanism is provided,
A vacuum annealing process is performed on the second sputtered film in the amorphous state formed on the second surface of the substrate, on the downstream side in the transport direction of the second film formation region of the second transport unit. A film forming apparatus provided with a vacuum annealing mechanism.   The first vacuum annealing mechanism performs a first vacuum annealing process on the first surface of the substrate on the first transport direction side of the second transport area with respect to the second film forming region. 4. The film forming apparatus according to claim 3, further comprising an annealing promoting vacuum annealing mechanism for performing a vacuum annealing process on said sputtered film. A film forming method for forming a film by sputtering on both surfaces of the substrate while moving the substrate in a vacuum,
A first film forming step of forming a first sputtered film in an amorphous state on a first surface of the substrate;
A first vacuum annealing process for performing a vacuum annealing process on the first sputtered film on the first surface of the substrate;
A second film forming step of forming a second sputtered film in an amorphous state on the second surface of the substrate;
Performing a vacuum annealing process on the second sputtered film on the second surface of the substrate.   After a first vacuum annealing process of performing a vacuum annealing process on the first sputtered film in the amorphous state on the first surface of the substrate and on the second surface of the substrate, a second amorphous state is formed. 6. The film forming method according to claim 5, further comprising, before the second film forming step of forming the sputtered film, an annealing promoting step of further performing a vacuum annealing process on the first sputtered film on the first surface of the substrate. . The substrate has an i-type amorphous silicon layer and a p-type amorphous silicon layer sequentially provided on a first surface of an n-type crystalline silicon substrate, and an i-type amorphous silicon layer is provided on a second surface of the n-type crystalline silicon substrate. A substrate in which a layer and an n-type amorphous silicon layer are sequentially provided,
The film formation according to claim 5, wherein the first sputtered film is a first transparent conductive oxide film, and the second sputtered film is a second transparent conductive oxide film. Method. A film forming method using the film forming apparatus according to claim 3,
Transporting the substrate holder in the first transport direction along the transport path so as to pass through the first film formation region by a first transport unit of the substrate holder transport mechanism; A first film forming step of forming a first sputtered film by sputtering on the first surface of the substrate held at
The substrate holder is transported in the first transport direction along the transport path by a first transport unit of the substrate holder transport mechanism, and the first sputter film on the first surface of the substrate is moved. A first vacuum annealing step of performing a vacuum annealing process by the first vacuum annealing mechanism;
A step of returning the substrate holder from the first transport section to the second transport section along the transport path while maintaining the vertical relationship of the substrate holder by the transport folding section of the substrate holder transport mechanism; When,
Transporting the substrate holder in the second transport direction along the transport path so as to pass through the second film formation region by a second transport unit of the substrate holder transport mechanism; A second film forming step of forming a second sputtered film by sputtering on the second surface of the substrate held at
The substrate holder is transported in the second transport direction along the transport path by a second transport unit of the substrate holder transport mechanism, and the second holder is transported with respect to the second sputtered film on the second surface of the substrate. A second vacuum annealing treatment step of performing a vacuum annealing treatment by the second vacuum annealing treatment mechanism. A film forming method using the film forming apparatus according to claim 4,
Transporting the substrate holder in the first transport direction along the transport path so as to pass through the first film formation region by a first transport unit of the substrate holder transport mechanism; A first film forming step of forming a first sputtered film by sputtering on the first surface of the substrate held at
The substrate holder is transported in the first transport direction along the transport path by a first transport unit of the substrate holder transport mechanism, and the first sputter film on the first surface of the substrate is moved. A first vacuum annealing step of performing a vacuum annealing process by the first vacuum annealing mechanism;
A step of returning the substrate holder from the first transport section to the second transport section along the transport path while maintaining the vertical relationship of the substrate holder by the transport folding section of the substrate holder transport mechanism; When,
The substrate that has been transported in the second transport direction along the transport path by the second transport unit of the substrate holder transport mechanism and that has been subjected to vacuum annealing by the first vacuum annealing mechanism An annealing accelerating step of further performing a vacuum annealing process on the first sputtered film on the first surface by the annealing accelerating vacuum annealing mechanism;
Transporting the substrate holder in the second transport direction along the transport path so as to pass through the second film formation region by a second transport unit of the substrate holder transport mechanism; A second film forming step of forming a second sputtered film by sputtering on the second surface of the substrate held at
The substrate holder is transported in the second transport direction along the transport path by a second transport unit of the substrate holder transport mechanism, and the second holder is transported with respect to the second sputtered film on the second surface of the substrate. A second vacuum annealing treatment step of performing a vacuum annealing treatment by the second vacuum annealing treatment mechanism. It is a manufacturing method of the solar cell using the film-forming apparatus of Claim 3, Comprising:
As the substrate, an i-type amorphous silicon layer and a p-type amorphous silicon layer are sequentially provided on a first surface of an n-type crystalline silicon substrate, and an i-type amorphous silicon layer is provided on a second surface of the n-type crystalline silicon substrate. Prepare a substrate on which a layer and an n-type amorphous silicon layer are sequentially provided,
Transporting the substrate holder in the first transport direction along the transport path so as to pass through the first film formation region by a first transport unit of the substrate holder transport mechanism; Forming a first transparent conductive oxide film in an amorphous state by sputtering on the first surface of the substrate held in;
The substrate holder is transported in the first transport direction along the transport path by a first transport unit of the substrate holder transport mechanism, and the first transparent substrate in the amorphous state on the first surface of the substrate is transported. A first vacuum annealing process for performing a vacuum annealing process on the conductive oxide film by the first vacuum annealing process mechanism;
A step of returning the substrate holder from the first transport section to the second transport section along the transport path while maintaining the vertical relationship of the substrate holder by the transport folding section of the substrate holder transport mechanism; When,
Transporting the substrate holder in the second transport direction along the transport path so as to pass through the second film formation region by a second transport unit of the substrate holder transport mechanism; Forming a second transparent conductive oxide film in an amorphous state by sputtering on the second surface of the substrate held in
The second transport unit of the substrate holder transport mechanism transports the substrate holder in the second transport direction along the transport path, and the second transparent substrate in the amorphous state on the second surface of the substrate. A second vacuum annealing step of performing a vacuum annealing process on the conductive oxide film by the second vacuum annealing mechanism. It is a manufacturing method of the solar cell using the film-forming apparatus of Claim 4, Comprising:
As the substrate, an i-type amorphous silicon layer and a p-type amorphous silicon layer are sequentially provided on a first surface of an n-type crystalline silicon substrate, and an i-type amorphous silicon layer is provided on a second surface of the n-type crystalline silicon substrate. Prepare a substrate on which a layer and an n-type amorphous silicon layer are sequentially provided,
Transporting the substrate holder in the first transport direction along the transport path so as to pass through the first film formation region by a first transport unit of the substrate holder transport mechanism; Forming a first transparent conductive oxide film in an amorphous state by sputtering on the first surface of the substrate held in;
The substrate holder is transported in the first transport direction along the transport path by a first transport unit of the substrate holder transport mechanism, and the first transparent substrate in the amorphous state on the first surface of the substrate is transported. A first vacuum annealing process for performing a vacuum annealing process on the conductive oxide film by the first vacuum annealing process mechanism;
A step of returning the substrate holder from the first transport section to the second transport section along the transport path while maintaining the vertical relationship of the substrate holder by the transport folding section of the substrate holder transport mechanism; When,
The substrate that has been transported in the second transport direction along the transport path by the second transport unit of the substrate holder transport mechanism and that has been subjected to vacuum annealing by the first vacuum annealing mechanism An annealing promoting step of further performing a vacuum annealing process on the first transparent conductive oxide film on the first surface by the annealing promoting vacuum annealing mechanism;
Transporting the substrate holder in the second transport direction along the transport path so as to pass through the second film formation region by a second transport unit of the substrate holder transport mechanism; Forming a second transparent conductive oxide film in an amorphous state by sputtering on the second surface of the substrate held in
The substrate holder is transported in the second transport direction along the transport path by a second transport unit of the substrate holder transport mechanism, and the second transparent conductive oxide on the second surface of the substrate is transported. A second vacuum annealing treatment step of performing a vacuum annealing treatment on the film by the second vacuum annealing treatment mechanism.

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