JP2013118351A - Manufacturing apparatus for solar cell, solar cell, and manufacturing method for solar cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lower the manufacturing cost of a heterojunction solar cell.SOLUTION: The manufacturing apparatus for solar cell includes: a substrate holder configured to hold a plurality of substrates in plane so that a first main surface and a second main surface of each of the substrates are both exposed; a pre-filming chamber in which a first film is formed on the first main surface of the substrate when the substrate holder is carried in to an anode electrode side; a post-filming chamber in which a second film is formed on the second main surface of the substrate when the substrate holder is carried in to the anode electrode side; a movement chamber connecting the pre-filming chamber and the post-filming chamber so as to convey the substrate holder from the pre-filming chamber to the post-filming chamber without opening the inside to the atmosphere; and a conveying mechanism which conveys the substrate holder along the first main surface at the major part of a conveyance path from the pre-filming chamber to the post-filming chamber without opening the inside to the atmosphere.

Description

  The present invention relates to a solar cell manufacturing apparatus, a solar cell, and a solar cell manufacturing method.

The solar power generation system is expected as clean energy that protects the global environment in the 21st century from the increase in carbon dioxide (CO ₂ ) gas due to the burning of fossil energy, and its production volume is exploding worldwide. .

  A current general crystalline silicon solar cell uses a p-type crystalline silicon substrate having a thickness of about 200 μm, and has a surface texture, an n-type impurity diffusion layer, an antireflection film, and a surface electrode (for example, comb type) that increase the light absorption rate. Ag electrodes) are sequentially formed on the front surface side of the substrate, and back electrodes (for example, Al electrodes) are formed on the back surface side of the substrate by screen printing, and then these are fired.

  In such firing, the solvent content of the front electrode and the back electrode is volatilized, and the comb-shaped Ag electrode penetrates the antireflection film and is connected to the n-type impurity diffusion layer on the light receiving surface side of the substrate. On the side, a part of Al of the Al electrode diffuses into the substrate to form a back surface field layer (BSF). The BSF layer has an effect of suppressing the carrier recombination in the vicinity of the Al electrode by forming an internal electric field at the joint surface with the silicon substrate to push back minority carriers generated in the vicinity of the BSF layer into the silicon substrate. However, the thickness of the junction and the BSF layer by this diffusion becomes a thick film thickness of several hundred nm to several μm when formed using a thermal process having an appropriate dopant concentration. Short circuit current decreases due to light absorption.

  Therefore, a heterojunction solar cell has been developed in which a junction made of an impurity-doped silicon layer or a BSF layer is formed on the back surface of a crystalline silicon substrate via a thin intrinsic semiconductor thin film (i layer).

  In a heterojunction solar cell, the impurity concentration distribution of the impurity-doped silicon layer can be freely set by forming the impurity-doped silicon layer on the back side as a thin film, and the recombination of carriers and light in the film is possible because the impurity layer is thin. Absorption can be suppressed, and a large short-circuit current can be obtained. In addition, since the intrinsic semiconductor layer inserted between them can suppress impurity diffusion between the junctions and form a junction having a steep impurity profile, a high open-circuit voltage can be obtained by forming a good junction interface.

  Furthermore, in the heterojunction solar cell, the intrinsic semiconductor thin film and the impurity-doped silicon layer on the back side can be formed at a low temperature of about 200 ° C., thereby reducing the stress and warpage of the substrate caused by heat even if the substrate is thin. can do. In addition, it can be expected that a decrease in substrate quality can be suppressed even for a crystalline silicon substrate that is easily deteriorated by heat.

  In manufacturing a heterojunction solar cell, for example, when an n-type crystalline silicon substrate is used, an intrinsic semiconductor thin film (i layer) and a p-type impurity doped silicon layer are formed on the front surface side, and an intrinsic semiconductor thin film ( i layer) and an n-type impurity-doped silicon layer are formed.

  On the other hand, in Patent Document 1, in the production of a semiconductor active layer having a PIN junction in a photovoltaic device, diborane is added to a mixed gas of silane and methane to form a P-type impurity layer, and silicon compound gas is used. It is described that an intrinsic layer is formed by forcibly mixing a nitrogen source gas and an oxygen source gas, and an N-type impurity layer is formed by adding phosphine to silane. Thereby, according to patent document 1, it is supposed that the deterioration rate of the photoelectric conversion efficiency by long-time irradiation of strong light can be suppressed by forcibly containing nitrogen and oxygen simultaneously in the intrinsic layer. .

  An in-line type CVD apparatus in which a plurality of reaction chambers are connected in series is known as an apparatus for forming a semiconductor thin film stack in which a plurality of types of films are stacked.

  In Patent Document 2, in a continuous separation plasma apparatus for forming a pin structure, a preparation chamber, a first reaction chamber, a second reaction chamber, a third reaction chamber, and an extraction chamber are provided in series, and a glass substrate is provided in each chamber. Describes that a p-type, i-type, and n-type amorphous semiconductor film is sequentially formed in the process of sequentially transporting to form a photovoltaic device. In the second reaction chamber of this continuous separation plasma apparatus, the interval between the upper discharge electrode and the lower discharge electrode is set so as to gradually increase along the traveling direction of the glass substrate and then gradually decrease. Thus, according to Patent Document 2, since the discharge power density can be accurately changed along the traveling direction of the substrate, a desired band is provided for each of the plurality of glass substrates moving in the reaction chamber. It is said that an i layer having a gap structure can be formed.

Japanese Patent Laid-Open No. 61-222277 Japanese Patent Laid-Open No. 6-151917

  Each of the techniques described in Patent Document 1 and Patent Document 2 is based on the premise that a film is formed on only one of two main surfaces of a glass substrate (insulating substrate). For this reason, Patent Document 1 and Patent Document 2 describe how to efficiently form different films on two main surfaces of a semiconductor substrate (for example, a silicon substrate) for manufacturing a heterojunction solar cell. There is no mention at all.

  If the continuous separation plasma apparatus described in Patent Document 2 is used to manufacture a heterojunction solar cell, a stack of different semiconductor thin films is formed on each of the two main surfaces (front and back surfaces) of the semiconductor substrate. In order to do so, a step of inverting the semiconductor substrate after forming a semiconductor thin film on one main surface of the semiconductor substrate is required. Therefore, a plurality of CVD apparatuses for forming the semiconductor thin film layers on the front surface side and the back surface side and an apparatus for inverting the silicon substrate between the respective CVD apparatuses are required. As a result, the apparatus cost increases and the manufacturing process becomes complicated, which may increase the manufacturing cost.

  This invention is made | formed in view of the above, Comprising: It aims at obtaining the manufacturing method of a solar cell which can reduce the manufacturing cost of a heterojunction solar cell, a solar cell, and the manufacturing method of a solar cell.

  In order to solve the above-described problems and achieve the object, a solar cell manufacturing apparatus according to one aspect of the present invention includes a first main surface and a second main surface opposite to the first main surface. A substrate holder for holding the plurality of substrates in a plane so that both the first main surface and the second main surface of the substrate are exposed, and the substrate holder is carried into the anode electrode side. When the substrate holder contacts the anode electrode, the second main surface is isolated from the discharge to be generated and the first main surface is exposed to the discharge to be generated. The substrate holder is placed as described above, and a first film is applied to the first main surface of the substrate by discharging high-frequency power between the cathode electrode and the anode electrode to discharge the first gas. The film formation chamber before film formation and the substrate holder are carried to the anode electrode side When the substrate holder is in contact with the anode electrode, the first main surface is isolated from the discharge to be generated and the second main surface is exposed to the discharge. A substrate holder is placed, and a second film is formed on the second main surface of the substrate by applying high-frequency power between the cathode electrode and the anode electrode to discharge the second gas. A post-deposition chamber; and a transport mechanism that transports the substrate holder in a direction along the first main surface in most of the transport path without opening the atmosphere from the pre-deposition chamber to the post-deposition chamber. It is characterized by having.

  According to the present invention, a process for inverting the substrate holder is unnecessary, and the size of the moving chamber connecting the pre-deposition chamber and the post-deposition chamber can be reduced as compared with the case of inverting. . Thereby, since a manufacturing process can be shortened and the enlargement of a manufacturing apparatus can be suppressed, the manufacturing cost of a heterojunction solar cell can be reduced.

FIG. 1 is a diagram illustrating a configuration of a solar cell manufacturing apparatus according to the first embodiment. FIG. 2 is a plan view showing the configuration of the solar cell substrate holder in the first embodiment. FIG. 3 is a cross-sectional view showing the configuration of the solar cell substrate holder in the first embodiment. FIG. 4 is a diagram illustrating a configuration of the film formation chamber in the first embodiment. FIG. 5 is a diagram illustrating the configuration and operation of the transport mechanism according to the first embodiment. FIG. 6 is a diagram illustrating the configuration and operation of the solar cell manufacturing apparatus according to the second embodiment. FIG. 7 is a diagram illustrating the configuration and operation of the solar cell manufacturing apparatus according to the second embodiment. FIG. 8 is a diagram illustrating a configuration of a film formation chamber in the second embodiment. FIG. 9 is a partial top view showing the configuration of the solar cell substrate tray in the third embodiment. FIG. 10 is a partial cross-sectional view showing the configuration of the solar cell substrate tray in the third embodiment. FIG. 11 is a partial top view showing a state in which the solar cell substrate tray, the substrate, and the solar cell substrate holder in Embodiment 3 are placed. 12 is a partial cross-sectional view in the CC direction in FIG. FIG. 13 is a partial cross-sectional view in the DD direction in FIG. FIG. 14 is a cross-sectional view showing a substrate over which an amorphous semiconductor layer is formed in Embodiment Mode 3. FIG. 15 is a partial top view showing an example of a state in which the solar cell substrate tray, the substrate, and the solar cell substrate holder in the third embodiment are placed. FIG. 16 is a partial top view showing an example of a state in which the solar cell substrate tray, the substrate, and the solar cell substrate holder in the third embodiment are placed. FIG. 17 is a partial top view showing an example of a state in which the solar cell substrate tray, the substrate, and the solar cell substrate holder in the third embodiment are placed. FIG. 18 is a top view showing a solar cell substrate on which a collecting electrode is formed in the third embodiment. FIG. 19 is a partial cross-sectional view in the EE direction in FIG. FIG. 20 is a partial top view showing an example of the configuration of the solar cell substrate tray in the third embodiment. FIG. 21 is a partial top view showing an example of a state in which the solar cell substrate tray, the substrate, and the solar cell substrate holder in the third embodiment are placed. FIG. 22 is a partial cross-sectional view in the HH direction in FIG. 23 is a partial cross-sectional view in the II direction in FIG. FIG. 24 is a partial cross-sectional view illustrating an example of a structure in a film formation chamber in Embodiment 4. FIG. 25 is a partial cross-sectional view illustrating an example of a structure in a film formation chamber in Embodiment 4. FIG. 26 is a partial cross-sectional view illustrating an example of a structure in the deposition chamber in Embodiment 4. FIG. 27 is a partial cross-sectional view illustrating an example of a structure in a film formation chamber in Embodiment 4.

  Embodiments of a solar cell manufacturing apparatus according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. Moreover, the solar cell manufacturing apparatus diagram used in the following embodiments is schematic, and the relationship between length, depth, height, ratios thereof, and the like are different from actual ones.

Embodiment 1 FIG.
A solar cell manufacturing apparatus 100 according to Embodiment 1 will be described with reference to FIG. FIG. 1 is a top view schematically showing an example of the configuration of a solar cell manufacturing apparatus 100.

  The solar cell manufacturing apparatus 100 is, for example, an in-line plasma CVD apparatus for manufacturing a heterojunction solar cell, and a plurality of film forming chambers are connected in series via a plurality of gate valves. Specifically, the solar cell manufacturing apparatus 100 includes a solar cell substrate holder 6, a load chamber 1, a first film formation chamber 21, a second film formation chamber 22, a moving chamber 3, a third film formation chamber 23, and a fourth. A film forming chamber 24, an unload chamber 4, a plurality of gate valves 5-1 to 5-6, and a transport mechanism 30 are provided.

  The solar cell substrate holder 6 holds a plurality of substrates 9-1 to 9-16 (see FIG. 2) in a plane so that both the front surface 9a and the back surface 9b (see FIG. 3) of each substrate 9 are exposed. . Each substrate 9 is formed of, for example, a material whose main component is a semiconductor (for example, silicon), and different films are deposited on both the front surface 9a and the back surface 9b so that a heterojunction solar cell is formed. It should be a substrate. The load chamber 1, the first film formation chamber 21, the second film formation chamber 22, the moving chamber 3, the third film formation chamber 23, the fourth film formation chamber 24, and the unload chamber 4 include a plurality of gate valves 5-1. 5-6 are connected in series.

  For example, the solar cell substrate holder 6 set substantially vertically is put into the load chamber 1 from the atmosphere with the gate valve 5-1 closed. After the load chamber 1 is evacuated, the gate valve 5-1 is opened, and the transfer mechanism 30 moves the solar cell substrate holder 6 from the load chamber 1 to the first film formation chamber along the surface 9a of the substrate 9. Transport to 21. After the gate valves 5-1 and 5-2 are closed and the first film formation chamber 21 is evacuated, the first film formation gas is introduced into the first film formation chamber 21, and the solar cell substrate holder 6. A first film is formed on the surface 9a of each substrate 9 held on the substrate. Similarly, the solar cell substrate holder 6 is sequentially moved to the next film formation chamber by the transport mechanism 30. After the film formation in each film formation chamber (the first film formation chamber 21, the second film formation chamber 22, the third film formation chamber 23, and the fourth film formation chamber 24) is completed, the solar cell substrate holder 6 is transferred to the transport mechanism 30. To the unload chamber 4. After the unload chamber 4 is released to the atmosphere, the solar cell substrate holder 6 is taken out of the solar cell manufacturing apparatus 100.

  In each film formation chamber (first film formation chamber 21, second film formation chamber 22, third film formation chamber 23, and fourth film formation chamber 24), a cathode electrode 7 and an anode electrode 8 are installed. The positional relationship between the cathode electrode 7 and the anode electrode 8 is such that the first film formation chamber 21 and the second film formation chamber 22, and the third film formation chamber 23 and the fourth film formation chamber 24 sandwich the moving chamber 3. It is reversed. That is, in each of the first film formation chamber 21 and the second film formation chamber 22, the cathode electrode 7 is located on the lower side in FIG. 1, and the anode electrode 8 is located on the upper side in FIG. On the other hand, in each of the third film formation chamber 23 and the fourth film formation chamber 24, the cathode electrode 7 is located on the upper side in FIG. 1, and the anode electrode 8 is located on the lower side in FIG. The solar cell substrate holder 6 moves in parallel along a direction (for example, a substantially vertical direction) intersecting the surface 9 a (see FIG. 3) of the substrate 9 in the moving chamber 3. In this case, film formation is performed in the state of being close to the anode electrode 8.

  The transport mechanism 30 transports the solar cell substrate holder 6 from the first film forming chamber 21 to the fourth film forming chamber 24 in the direction along the surface 9 a of the substrate 9 in most of the transport path without opening to the atmosphere. Specifically, the transport mechanism 30 includes a first transport mechanism 31, a second transport mechanism 32, and a third transport mechanism 33.

  The first transport mechanism 31 is a mechanism capable of transporting along the surface 9a of the substrate 9 (see FIG. 3). For example, the first transfer mechanism 31 sequentially transfers the solar cell substrate holder 6 from the load chamber 1 to the first film forming chamber 21, the second film forming chamber 22, and the moving chamber 3 along the surface 9 a of the substrate 9. I will do it. For example, the first transport mechanism 31 includes a stator 31a, a mover 31b, and a holding portion 31c (see FIG. 5A). The stator 31 a extends in a direction along the surface 9 a of the substrate 9. The mover 31b is configured to be movable along the longitudinal direction of the stator 31a. For example, the stator 31a and the mover 31b may constitute a linear motor in which one has a permanent magnet and the other has an electromagnet. The holding portion 31c is coupled to the mover 31b and moves together with the mover 31b while holding the solar cell substrate holder 6. The holding part 31c may hold | maintain the side surface 6a, 6b vicinity of the side along the longitudinal direction of the manufacturing apparatus 100 among 4 side surface 6a-6d of the solar cell substrate holder 6, for example (FIG. 2, FIG. )reference).

  The 2nd conveyance mechanism 32 is a mechanism which can be conveyed along the direction (for example, substantially perpendicular direction) which cross | intersects the surface 9a (refer FIG. 3) of the board | substrate 9. FIG. For example, the second transport mechanism 32 moves the solar cell substrate holder 6 from the position corresponding to the anode electrode 8 of the second film forming chamber 22 to the position corresponding to the anode electrode 8 of the third film forming chamber 23 in the moving chamber 3. Move. For example, the second transport mechanism 32 includes a stator 32a, a mover 32b, and a holding portion 32c (see FIG. 5B). The stator 32a extends in a direction intersecting the surface 9a of the substrate 9 (for example, a substantially vertical direction). The stator 32a is arranged on the opposite side of the stator 31a with respect to the solar cell substrate holder 6, for example. The mover 32b is configured to be movable along the longitudinal direction of the stator 32a. For example, the stator 32a and the mover 32b may constitute a linear motor in which one has a permanent magnet and the other has an electromagnet. The holding part 32c is coupled to the mover 32b and moves together with the mover 32b while holding the solar cell substrate holder 6. The holding part 32c may hold | maintain the side surface 6c vicinity of the side which cross | intersects the longitudinal direction of the manufacturing apparatus 100 among 4 side surface 6a-6d of the solar cell substrate holder 6, for example (refer FIG. 2, FIG.5 (b)). ).

  The third transport mechanism 33 is a mechanism capable of transporting along the surface 9a of the substrate 9 (see FIG. 3). For example, the third transfer mechanism 33 sequentially transfers the solar cell substrate holder 6 from the moving chamber 3 to the third film forming chamber 23, the fourth film forming chamber 24, and the unload chamber 4 along the surface 9 a of the substrate 9. I will do it. For example, the third transport mechanism 33 includes a stator 33a, a mover 33b, and a holding portion 33c (see FIG. 5C). The stator 33 a extends in a direction along the surface 9 a of the substrate 9. The mover 33b is configured to be movable along the longitudinal direction of the stator 33a. For example, the stator 33a and the mover 33b may constitute a linear motor in which one has a permanent magnet and the other has an electromagnet. The holding portion 33c is coupled to the mover 33b and moves together with the mover 33b while holding the solar cell substrate holder 6. The holding part 33c may hold | maintain the side surface 6a, 6b vicinity of the side along the advancing direction among 4 side surface 6a-6d of the solar cell substrate holder 6, for example (refer FIG. 2, FIG.5 (c)).

  In this way, the transport mechanism 30 moves the solar cell substrate holder 6 from the first film formation chamber 21 to the fourth film formation chamber 24 in the direction along the surface 9a of the substrate 9 in the most part of the transport path without opening the atmosphere. Since it carries, it becomes possible to form into a film on both surfaces (the surface 9a and the back surface 9b) of the board | substrate 9, without reversing the solar cell substrate holder 6 largely. This eliminates the need for a process for reversing the solar cell substrate holder 6 (such as the opening of the atmosphere for rotating or a vacuuming process), and makes the size of the moving chamber 3 smaller than when performing reversal. be able to. For example, the size of the moving chamber 3 can be minimized with respect to movement in the lateral direction (direction substantially perpendicular to the surface 9 a of the substrate 9) by the second transport mechanism 32.

  Next, the configuration of the solar cell substrate holder 6 will be described with reference to FIGS. FIG. 2 is a plan view showing the configuration of the solar cell substrate holder 6. For example, FIG. 2 is a diagram showing the configuration when the solar cell substrate holder 6 is viewed from below in FIG. 1. FIG. 3 is a cross-sectional view showing the configuration of the solar cell substrate holder 6 and is a cross-sectional view taken along the line AA in FIG.

  As shown in FIG. 2, a plurality of substrates 9-1 to 9-16 are placed on the solar cell substrate holder 6 and can be simultaneously formed on the plurality of substrates 9-1 to 9-16. It is. Each substrate 9 is made of, for example, a material (for example, crystal) whose main component is a semiconductor (for example, silicon), and is different from each other on both the front surface 9a and the back surface 9b so that a heterojunction solar cell is formed. The substrate on which the film is to be deposited.

  As shown in FIG. 3, the solar cell substrate holder 6 includes a solar cell substrate tray 61 and a solar cell substrate holder 62. The substrate 9 is fixed so that the edge portion is sandwiched between the solar cell substrate tray 61 and the solar cell substrate holder 62. Moreover, both the solar cell substrate tray 61 and the solar cell substrate holder 62 are provided with openings 61a and 62a, and the substrate 9 is exposed so that the front surface 9a and the back surface 9b can be exposed to plasma, respectively. That is, the solar cell substrate holder 6 holds the plurality of substrates 9-1 to 9-16 (see FIG. 2) so that both the front surface 9a and the back surface 9b (see FIG. 3) of each substrate 9 are exposed. Thereby, it is possible to form a film on both the front surface 9a and the back surface 9b of each substrate 9. As the material for the solar cell substrate tray 61 and the solar cell substrate holder 62, ceramic materials such as aluminum and alumina whose surfaces are anodized, carbon composite materials, and the like can be used.

  Next, the configuration of each film forming chamber (the first film forming chamber 21, the second film forming chamber 22, the third film forming chamber 23, and the fourth film forming chamber 24) will be described with reference to FIG. FIG. 4 exemplarily shows a top view when the first film forming chamber 21 shown in FIG. 1 is rotated 90 ° clockwise.

  The first film forming chamber 21 is a space that can be evacuated and surrounded by the chamber wall CH. An exhaust port CHa and a supply port CHb are formed in the chamber wall CH. In the first film forming chamber 21, the anode electrode 8 and the cathode electrode 7 are disposed so as to face each other. The cathode electrode 7 is provided with a plurality of openings 7a in a shower shape, for example. The cathode electrode 7 is electrically connected to the high frequency power supply 10, for example. The anode electrode 8 is electrically connected to the ground potential, for example.

  After the inside of the first film forming chamber 21 is evacuated by the vacuum pump through the exhaust port CHa, the solar cell substrate holder 6 is carried into the anode electrode 8 side by the first transport mechanism 31 as shown in FIG. It arrange | positions in the electrode 8 vicinity. The solar cell substrate holder 6 is placed so as to be in contact with the anode electrode 8, for example. At this time, for example, the front surface 9a of the two main surfaces (the front surface 9a and the back surface 9b) of each substrate 9 held by the solar cell substrate holder 6 faces the cathode electrode 7 side. Then, in the space SP between the anode electrode 8 and the cathode electrode 7, from a gas supply source (not shown) through the process gas control system 11 and the supply port CHb and the shower-like opening 7 a of the cathode electrode 7. Process gas is supplied. Further, high frequency power (high frequency bias) supplied from the high frequency power supply 10 is applied to the cathode electrode 7, and plasma PL is generated in the space SP between the cathode electrode 7 and the anode electrode 8. The chemically active species generated in the plasma PL becomes a film formation precursor, and reacts with the main surface of the substrate 9 (in this case, the surface 9a) to form a desired film. For example, when the solar cell substrate holder 6 is placed so as to contact the anode electrode 8, the solar cell substrate holder 6 is formed only on the main surface exposed to the plasma PL (in this case, the surface 9 a) out of the two main surfaces of the substrate 9. A film is formed, and no film is formed on the opposite main surface (in this case, the back surface 9 b) in contact with the anode electrode 8. Although not shown, the anode electrode 8 is heated by a heater to control the temperature of the solar cell substrate holder 6 and the substrate 9. Process gases and reaction products that do not contribute to the reaction are discharged out of the film forming chamber by the vacuum pump through the exhaust port CHa.

  In the second film formation chamber 22 as well, the surface 9a of the two main surfaces (the front surface 9a and the back surface 9b) of each substrate 9 held by the solar cell substrate holder 6 faces the cathode electrode 7 side. 9 is the same as the above in that film formation is performed on the surface 9a side. On the other hand, in the third film formation chamber 23 and the fourth film formation chamber 24, the back surface 9b of the two main surfaces (the front surface 9a and the back surface 9b) of each substrate 9 held by the solar cell substrate holder 6 is a cathode. It differs from the above in that it is directed to the electrode 7 side and the film is formed on the back surface 9b side of each substrate 9. Other points are the same as above.

  Next, the film forming process will be described with reference to FIGS. FIGS. 5A, 5 </ b> B, and 5 </ b> C are diagrams illustrating operations when the first transport mechanism 31, the second transport mechanism 32, and the third transport mechanism 33 are viewed from below in FIG. 1. .

  As the substrate 9, an n-type single crystal silicon substrate is used, and when the opening 62 a side of the solar cell substrate holder 62 is operated as a solar cell, a light receiving surface (surface 9 a) on which sunlight is incident is used. An n-type single crystal silicon substrate (substrate 9) is placed on the solar cell substrate holder 6 so that the opening 61a side of the substrate tray 61 is the back surface 9b. With the gate valve 5-1 closed, the solar cell substrate holder 6 is put into the load chamber 1 and the load chamber 1 is evacuated. Thereafter, the first transfer mechanism 31 moves the solar cell substrate holder 6 to the first film formation chamber 21 with the gate valve 5-1 opened. The solar cell substrate holder 6 is disposed in the vicinity of the anode electrode 8 so that the opening 62a side of the solar cell substrate holder 62 is exposed to the plasma PL. Then, after the gate valves 5-1 and 5-2 are closed and the first film formation chamber 21 is evacuated, silane gas and hydrogen gas are first used as process gases for forming an i-type amorphous silicon layer. It is introduced into the film forming chamber 21. At this time, for example, the process gas control system 11 or the like sets the flow rate of hydrogen gas to a range of 0 to 20 times the silane gas flow rate, and controls the pressure to be a constant value in the range of 50 to 500 Pa. The substrate temperature is controlled to be a constant value of 100 to 200 ° C. For example, a high frequency power (high frequency bias) of 10 to 100 mW per square centimeter of power density is applied between the cathode electrode 7 and the anode electrode 8 to discharge the process gas. Thereby, for example, an i-type amorphous silicon layer having a thickness of 2 to 10 nm is formed on the surface 9 a side of each substrate 9.

  Next, with the gate valve 5-2 opened, the first transport mechanism 31 moves the solar cell substrate holder 6 to the second film formation chamber 22. Then, after the gate valves 5-2 and 5-3 are closed and the inside of the second film forming chamber 22 is evacuated, silane gas, diborane gas and hydrogen gas are used as process gases for forming a p-type amorphous silicon layer. It is introduced into the second film formation chamber 22. At this time, for example, the flow rate of hydrogen gas with respect to the silane gas flow rate is set to a range of 0 to 20 times so that the diborane gas flow rate with respect to the silane gas flow rate becomes 0.4 to 5.0% by the process gas control system 11 or the like. Each is set and controlled to be a constant value in the range of 50 to 500 Pa, and the substrate temperature is controlled to be a constant value of 100 to 200 ° C. For example, a high frequency power (high frequency bias) of 10 to 100 mW per square centimeter of power density is applied between the cathode electrode 7 and the anode electrode 8 to discharge the process gas. Thereby, for example, a p-type amorphous silicon layer having a film thickness of 2 to 10 nm is formed on the surface 9 a side of each substrate 9.

  Note that methane gas or monomethylsilane gas may be used as a process gas in order to form a p-type amorphous silicon carbide layer having a wider band gap and higher light transmittance than the p-type amorphous silicon layer.

  Next, the 1st conveyance mechanism 31 moves the solar cell substrate holder 6 to the movement chamber 3 in the state which opened the gate valve 5-3. Specifically, as shown in FIG. 5A, the first transport mechanism 31 moves the solar cell substrate holder 6 along the surface 9 a of each substrate 9. That is, the first transport mechanism 31 moves the solar cell substrate holder 6 from the position near the anode electrode 8 in the second film forming chamber 22 to a position corresponding to the anode electrode 8 in the second film forming chamber 22 in the moving chamber 3. Move.

  And the 2nd conveyance mechanism 32 hold | maintains the solar cell substrate holder 6 in the position corresponding to the anode electrode 8 of the 2nd film-forming chamber 22 in the movement chamber 3, as shown in FIG.5 (b). Thereafter, the first transport mechanism 31 releases the holding of the solar cell substrate holder 6. The second transport mechanism 32 moves the solar cell substrate holder 6 in the lateral direction within the moving chamber 3. Specifically, the second transport mechanism 32 moves the solar cell substrate holder 6 in a direction substantially perpendicular to the surface 9a of each substrate 9 (for example, in a direction approaching to the front side of FIG. 5B). . That is, the second transport mechanism 32 moves the solar cell substrate holder 6 from the position corresponding to the anode electrode 8 of the second film forming chamber 22 in the moving chamber 3 to the anode electrode 8 of the third film forming chamber 23 in the moving chamber 3. Move to a position corresponding to. At this time, the gate valves 5-3 and 5-4 may be closed.

  Further, as shown in FIG. 5C, the third transport mechanism 33 holds the solar cell substrate holder 6 at a position corresponding to the anode electrode 8 of the third film forming chamber 23 in the moving chamber 3. Thereafter, the second transport mechanism 32 releases the holding of the solar cell substrate holder 6. With the gate valve 5-4 opened, the third transport mechanism 33 moves the solar cell substrate holder 6 to the second film formation chamber 23. Specifically, as shown in FIG. 5C, the third transport mechanism 33 moves the solar cell substrate holder 6 along the surface 9 a of each substrate 9. That is, the third transport mechanism 33 moves the solar cell substrate holder 6 from a position corresponding to the anode electrode 8 of the third film forming chamber 23 in the moving chamber 3 to a position near the anode electrode 8 in the third film forming chamber 23. Move.

  The solar cell substrate holder 6 is moved in the lateral direction (a direction substantially perpendicular to the surface 9a of each substrate 9) in the moving chamber 3, so that the opening 61a side of the solar cell substrate tray 61 is exposed to plasma. The solar cell substrate holder 6 is disposed in the vicinity of the anode electrode 8. Then, after the gate valves 5-4 and 5-5 are closed and the inside of the third film formation chamber 23 is evacuated, a silane gas and a hydrogen gas are used as process gases to form an i-type amorphous silicon layer. It is introduced into the film forming chamber 23. At this time, for example, the process gas control system 11 or the like sets the flow rate of hydrogen gas to a range of 0 to 20 times the silane gas flow rate, and controls the pressure to be a constant value in the range of 50 to 500 Pa. The substrate temperature is controlled to be a constant value of 100 to 200 ° C. For example, a high frequency power (high frequency bias) of 10 to 100 mW per square centimeter of power density is applied between the cathode electrode 7 and the anode electrode 8 to discharge the process gas. Thereby, for example, an i-type amorphous silicon layer having a thickness of 2 to 10 nm is formed on the back surface 9 b side of each substrate 9.

  Next, with the gate valve 5-5 opened, the third transport mechanism 33 moves the solar cell substrate holder 6 to the fourth film formation chamber 24. Then, after closing the gate valves 5-5 and 5-6 and evacuating the fourth film formation chamber 24, silane gas, phosphine gas and hydrogen gas are used as process gases to form an n-type amorphous silicon layer. Is introduced into the fourth film forming chamber 24. At this time, for example, by the process gas control system 11 or the like, the flow rate of hydrogen gas with respect to the silane gas flow rate is set to a range of 0 to 20 times so that the phosphine gas flow rate with respect to the silane gas flow rate is 0.4 to 5.0%. The pressure is controlled to be a constant value in the range of 50 to 500 Pa, and the substrate temperature is controlled to be a constant value of 100 to 200 ° C. For example, a high frequency power (high frequency bias) of 10 to 100 mW per square centimeter of power density is applied between the cathode electrode 7 and the anode electrode 8 to discharge the process gas. Thereby, for example, an n-type amorphous silicon layer having a thickness of 2 to 20 nm is formed on the back surface 9 b side of each substrate 9.

  After the film formation in the fourth film formation chamber 24 is completed, the third transport mechanism 33 moves the solar cell substrate holder 6 to the unload chamber 4 with the gate valve 5-6 opened. Then, after the unload chamber 4 is released to the atmosphere with the gate valve 5-6 closed, the solar cell substrate holder 6 is taken out. Thus, a laminated body of an i-type amorphous silicon layer and a p-type amorphous silicon layer is formed on the light-receiving surface side of the n-type single crystal silicon substrate, and an i-type amorphous silicon layer and an n-type film are formed on the back surface side. A laminated body with an amorphous silicon layer is formed.

  In the capacitively coupled plasma CVD film forming apparatus using plasma generated by the high-frequency electric field applied between the cathode electrode 7 and the anode electrode 8 facing each other, the substrate 9 or the solar cell substrate holder 6 is attached to the apparatus. An amorphous silicon layer constituting a heterojunction solar cell can be continuously formed on both surfaces of the substrate 9 without taking out the mechanism or a mechanism for inverting the substrate 9 or the solar cell substrate holder 6.

  The capacitively coupled plasma CVD method has a milder ionization in the plasma than the inductively coupled plasma CVD method, so it is less prone to excessive decomposition of reaction product species such as silane gas. It is advantageous in that a suitable high quality amorphous silicon layer with few defects in the film is formed.

  In the present embodiment, each layer is formed in an independent film formation chamber, but a continuous film may be formed in the same film formation chamber. For example, in the first film formation chamber 21, The second film formation chamber 22 may be omitted by continuously forming the i-type amorphous silicon layer and the p-type amorphous silicon layer. Further, the film formation order on the light receiving surface side and the back surface side may be reversed. Further, a preheating chamber may be provided between the load chamber 1 and the first film formation chamber 21.

  Further, a p-type single crystal silicon substrate, an n-type polycrystalline silicon substrate, or a p-type polycrystalline silicon substrate may be used as the solar cell crystal substrate.

  As described above, in the first embodiment, the solar cell substrate holder 6 uses the plurality of substrates 9-1 to 9-16 (see FIG. 2) as both the front surface 9a and the back surface 9b of each substrate 9 (see FIG. 3). Is held flat so that is exposed. Then, the transport mechanism 30 transports the solar cell substrate holder 6 from the first film formation chamber 21 to the fourth film formation chamber 24 in the direction along the surface 9a of the substrate 9 in most of the transport path without opening to the atmosphere. . Thereby, since it becomes possible to form a film on both surfaces (front surface 9a and back surface 9b) of the substrate 9 without largely reversing the solar cell substrate holder 6, a process (rotation) for reversing the solar cell substrate holder 6 is possible. And the like, and the size of the moving chamber 3 can be reduced as compared with the case of inversion. Therefore, since the manufacturing process can be shortened and the increase in the size of the manufacturing apparatus can be suppressed, the manufacturing cost of the heterojunction solar cell can be reduced.

  In the first embodiment, the positional relationship between the cathode electrode 7 and the anode electrode 8 in each of the first film forming chamber 21 and the second film forming chamber 22 is the third film forming chamber 23 and the fourth film forming chamber 24. These are opposite to the positional relationship between the cathode electrode 7 and the anode electrode 8. Thereby, the transfer mechanism 30 moves the solar cell substrate holder 6 to the first film formation chamber 21, the second film formation chamber 22, the third film formation chamber 23, and the fourth film formation chamber 24 without inverting the substrate 9. By sequentially conveying, film formation on both the front surface 9a and the back surface 9b of each substrate 9 becomes possible. This eliminates the need for a process for reversing the solar cell substrate holder 6 (such as the opening of the atmosphere for rotating or a vacuuming process), and makes the size of the moving chamber 3 smaller than when performing reversal. be able to. For example, the size of the moving chamber 3 can be minimized with respect to movement in the lateral direction (direction substantially perpendicular to the surface 9 a of the substrate 9) by the second transport mechanism 32. Therefore, since the manufacturing process can be shortened and the size of the manufacturing apparatus can be suppressed, the manufacturing cost of the heterojunction crystal solar cell can be reduced.

  In the first embodiment, in the transport mechanism 30, the first transport mechanism 31 moves the solar cell substrate holder 6 from the load chamber 1 to the first film formation chamber 21 and the second film formation along the surface 9 a of the substrate 9. The material is sequentially transferred to the chamber 22 and the moving chamber 3. The second transfer mechanism 32 moves the solar cell substrate holder 6 from the position corresponding to the anode electrode 8 in the second film forming chamber 22 to the position corresponding to the anode electrode 8 in the third film forming chamber 23 in the moving chamber 3. . The third transfer mechanism 33 sequentially transfers the solar cell substrate holder 6 from the moving chamber 3 to the third film forming chamber 23, the fourth film forming chamber 24, and the unload chamber 4 along the surface 9a of the substrate 9. Go. Thereby, the apparatus which can form into the film on both surfaces of the surface 9a and the back surface 9b in the board | substrate 9 without inverting the board | substrate 9 is realizable with simple structure.

  Moreover, in Embodiment 1, the 1st conveyance mechanism 31 hold | maintains the side surface 6a, 6b vicinity of the side along the longitudinal direction of the manufacturing apparatus 100 among 4 side surface 6a-6d of the solar cell substrate holder 6, for example, The 2nd conveyance mechanism 32 hold | maintains the side surface 6c vicinity of the side which cross | intersects the longitudinal direction of the manufacturing apparatus 100 among the 4 side surfaces 6a-6d of the solar cell substrate holder 6, for example, and the 3rd conveyance mechanism 33 is solar, for example Of the four side surfaces 6a to 6d of the battery substrate holder 6, the vicinity of the side surfaces 6a and 6b on the side along the traveling direction is held. That is, the first transport mechanism 31 and the second transport mechanism 32 hold the vicinity of different side surfaces among the four side surfaces 6a to 6d of the solar cell substrate holder 6, and the second transport mechanism 32 and the third transport mechanism 33 are solar. Of the four side surfaces 6 a to 6 d of the battery substrate holder 6, different side surface neighborhoods are held. Thereby, the delivery of the solar cell substrate holder 6 between the first transport mechanism 31 and the second transport mechanism 32 can be performed smoothly and the space for the delivery can be suppressed to a compact one. In addition, the solar cell substrate holder 6 can be smoothly transferred between the second transfer mechanism 32 and the third transfer mechanism 33, and the space for transfer can be suppressed to a compact one.

  Further, in the first embodiment, the moving chamber 3 has the first film forming chamber 21, the second film forming chamber 22, the third film forming chamber 23, and the fourth film forming chamber in the direction along the surface 9a of the substrate 9. 24. Accordingly, the second transport mechanism 32 of the transport mechanism 30 moves the solar cell substrate holder 6 from the position corresponding to the anode electrode 8 of the second film forming chamber 22 in the moving chamber 3 to the anode electrode 8 of the third film forming chamber 23. It is easy to keep the stroke short when moving to a position corresponding to.

Embodiment 2. FIG.
Next, the solar cell manufacturing apparatus 200 according to the second embodiment will be described with reference to FIGS. 6 and 7. 6 and 7 are top views schematically showing an example of the configuration and operation of the solar cell manufacturing apparatus 200. FIG. Below, it demonstrates focusing on a different part from Embodiment 1. FIG.

  The solar cell manufacturing apparatus 200 according to the second embodiment includes, for example, an in-line type CVD apparatus in which a plurality of film formation chambers L1 and L2 connected in series via a plurality of gate valves are arranged in two rows in parallel. It is. In the series L1, the load chamber 201-1, the first film formation chamber 221-1, the second film formation chamber 222-1, the third film formation chamber 223-1, the fourth film formation chamber 224-1, and the unload chamber 204 are displayed. -1 are connected in series via a plurality of gate valves 5-11 to 5-16. Similarly, in the series L2, the load chamber 201-2, the first film formation chamber 221-2, the second film formation chamber 222-2, the third film formation chamber 223-2, the fourth film formation chamber 224-2, The load chamber 204-2 is connected in series via a plurality of gate valves 5-21 to 5-26.

  Between the second film formation chambers 222-1 and 222-2 and the third film formation chambers 223-1 and 223-2, there is a common transfer chamber 203 in both rows of gate valves 5-13, 5-23, and 5-14. , 5-24. The moving chamber 203 connects the second film forming chamber 222-1 of the series L1 and the third film forming chamber 223-2 of the series L2 in a direction intersecting the surface 9a of the substrate 9. The moving chamber 203 connects the second film forming chamber 222-2 of the series L2 and the third film forming chamber 223-1 of the series L1 in a direction intersecting the opposite side to the surface 9a of the substrate 9. .

  The transport mechanism 230 includes a first transport mechanism 231, a second transport mechanism 232, a third transport mechanism 233, a fourth transport mechanism 234, and a fifth transport mechanism 235.

  As shown in FIG. 6, the first transport mechanism 231 moves the solar cell substrate holder 6-1 from the load chamber 201-1 in the series L1 along the surface 9a of the substrate 9 to the first film formation chamber 221-1 and the first film formation chamber 221-1. 2 The film is sequentially transferred to the film forming chamber 222-1 and the moving chamber 203. The second transport mechanism 232 moves the solar cell substrate holder 6-1 from the position corresponding to the anode electrode 8 of the second film forming chamber 222-1 of the series L1 in the moving chamber 203 to the third film forming chamber 223 of the series L2. It is moved in parallel to a position corresponding to the second anode electrode 8. The third transport mechanism 233 moves the solar cell substrate holder 6-1 from the moving chamber 203 along the surface 9a of the substrate 9 to the third film forming chamber 223-2, the fourth film forming chamber 224-2, and the unroller in the series L2. The material is sequentially transferred to the load chamber 204-2.

  At this time, the positional relationship between the cathode electrode 7 and the anode electrode 8 in each of the first film formation chamber 221-1 and the second film formation chamber 222-1 of the series L1 is the third film formation chamber 223-2 of the series L2. The positional relationship between the cathode electrode 7 and the anode electrode 8 in each of the fourth film formation chambers 224-2 is reversed.

  7, the fourth transport mechanism 234 moves the solar cell substrate holder 6-2 along the surface 9a of the substrate 9 from the load chamber 201-2 in the series L2 to the first film formation chamber 221-2. Then, the film is sequentially transferred to the second film formation chamber 222-2 and the moving chamber 203. The second transport mechanism 232 moves the solar cell substrate holder 6-2 from the position corresponding to the anode electrode 8 of the second film forming chamber 222-2 of the series L2 in the moving chamber 203 to the third film forming chamber 223 of the series L1. It is moved in parallel to a position corresponding to one anode electrode 8. The fifth transport mechanism 235 moves the solar cell substrate holder 6-2 from the moving chamber 203 along the surface 9a of the substrate 9 to the third film forming chamber 223-1, the fourth film forming chamber 224-1 in the series L1, and the unloading chamber 203. The material is sequentially transferred to the load chamber 204-1.

  At this time, the positional relationship between the cathode electrode 7 and the anode electrode 8 in the first film formation chamber 221-2 and the second film formation chamber 222-2 of the series L2 is the third film formation chamber 223-1 of the series L1, The positional relationship between the cathode electrode 7 and the anode electrode 8 in each of the fourth film formation chambers 224-1 is reversed.

  Thus, unlike the first embodiment, in each of the series L1 and L2, the positional relationship between the cathode electrode 7 and the anode electrode 8 in the film forming chamber is not reversed and the both sides of the substrate 9 are respectively reversed. Therefore, the cathode electrode 7 is arranged inside the manufacturing apparatus 200 and the anode electrode 8 is arranged outside the manufacturing apparatus 200 from the cathode electrode 7 in all film forming chambers. That is, the cathode electrode 7 of each film forming chamber in the series L1 is arranged on the series L2 side, and the cathode electrode 7 of each film forming chamber in the series L2 is arranged on the series L1 side.

  At this time, as shown in FIG. 8, the cathode electrode 7 in the film forming chamber (for example, the first film forming chamber 221-1 and the first film forming chamber 221-2) corresponding to the series L1 and the series L2 is manufactured. By setting it inside 200, facilities, such as a process gas control system 211 and a high frequency power supply, can be concentrated and arrange | positioned inside the manufacturing apparatus 200, and the manufacturing apparatus 200 can be reduced in size. In addition, since the high-frequency power source and the process gas system are not connected and the anode electrode 8 having a simple structure can be disposed outside the cathode electrode 7, maintenance work when the film forming chamber is opened to the atmosphere and cleaned, etc. Becomes easy.

  As described above, in the second embodiment, it is possible to perform continuous film formation on both surfaces of the substrate without a process of inverting the substrate with a simple structure, and the throughput is increased by arranging the film formation chambers in parallel. The manufacturing cost can be reduced.

Embodiment 3 FIG.
Next, a solar cell manufacturing apparatus according to Embodiment 3 will be described. Below, it demonstrates centering on a different part from Embodiment 1 and Embodiment 2. FIG.

  In Embodiment 1 and Embodiment 2, the shape of the openings 61a and 62a in the solar cell substrate holder 6 is not specifically limited. However, in Embodiment 3, the solar cell substrate holder 306 includes the openings 61a and 62a. The following devices are added to the shape of 62a.

  For example, the solar cell substrate holder 306 has a configuration as shown in FIGS.

  FIG. 9 is a plan view showing the configuration of the solar cell substrate holder 306 in a state where the solar cell substrate tray 61 is prepared and the substrate 9 and the solar cell substrate holder 362 are not yet placed. A plurality of substrates 9-1 to 9-16 are arranged in a matrix on the solar cell substrate tray 61 as shown in FIG. 2, and FIG. 9 shows a portion corresponding to one substrate 9. Yes. FIG. 10 is a view showing a cross section when the solar cell substrate tray 61 shown in FIG. 9 is cut along the line BB. As shown in FIG. 10, a counterbore 61 b is formed in a frame shape in the vicinity of the peripheral edge 61 a 1 of the opening 61 a in the solar cell substrate tray 61.

  FIG. 11 is a plan view showing the configuration of the solar cell substrate holder 306 in a state where the substrate 9 is placed on the solar cell substrate tray 61 and the solar cell substrate holder 362 is further placed and the substrate 9 is fixed. FIG. 11 is a plan view corresponding to FIG. 9 and shows a portion corresponding to one substrate 9. 12 is a view showing a cross section when the solar cell substrate holder 362 and the solar cell substrate tray 61 shown in FIG. 9 are cut along the line CC, and FIG. 13 is a diagram showing the solar cell substrate holder shown in FIG. It is a figure which shows the cross section at the time of cutting 362 and the solar cell board | substrate tray 61 along DD line.

  As FIG. 12 shows, since the width | variety of the direction along the CC line of the opening part 362a of the solar cell board | substrate holding | suppressing 362 is narrower than the board | substrate 9, the board | substrate 9 is a direction along the CC line. Are sandwiched and fixed between the solar cell substrate tray 61 and the solar cell substrate holder 362 at a pair of edge portions orthogonal to each other. On the other hand, as shown in FIG. 13, the width of the opening 362 a of the solar cell substrate holder 362 in the direction along the line DD is the same as that of the substrate 9 or about 0.5 to 2.0 mm wide. The surface 9a of the substrate 9 is exposed to plasma over its entire width.

  In this state, as in the first embodiment, film formation is performed on the surface 9a of the substrate 9 in the first film formation chamber 21 and the second film formation chamber 22, and then the third film formation chamber 23 and the fourth film formation chamber 24 are formed. Then, a film is formed on the back surface 9b of the substrate 9 (see FIG. 1). FIG. 14 shows a DD cross section of the substrate 9 after film formation. An i-type amorphous silicon layer 14 and a p-type amorphous silicon layer 15 are sequentially stacked on the surface 9 a of the substrate 9, and an i-type amorphous silicon layer is formed on the back surface 9 b of the substrate 9. 14 and an n-type amorphous silicon layer 16 are sequentially stacked.

  As shown in FIG. 14, the film is formed on the front surface 9 a over substantially the entire width of the substrate 9, but the edge 9 b 1 of the back surface 9 b is covered with the solar cell substrate holder 362 and has a region that is not formed. Exists. Therefore, the p-type amorphous silicon layer 15 formed on the front surface 9a and the n-type amorphous silicon layer 16 formed on the back surface 9b do not contact each other until reaching the vicinity of the end face of the substrate 9. Thus, the leakage current at the end face can be suppressed. In addition, an i-type amorphous silicon layer 14 and a p-type amorphous silicon layer 15 are stacked substantially over the entire surface 9a of the substrate 9, and a pin type diode structure is formed with the n-type silicon substrate. Therefore, the peripheral portion where the i-type amorphous silicon layer 14 and the n-type amorphous silicon layer 16 are not formed on the back surface 9b also functions as a solar cell, and has an effective area as a solar cell. Therefore, cell conversion efficiency can be improved. For example, it is desirable that the width of the non-deposition region of the edge portion 9b1 of the back surface 9b be 0.5 to 5 mm.

  As described above, in the third embodiment, when the surface 9a (light-receiving surface) of the substrate 9 is formed, the first direction along the surface 9a of the substrate 9 (the direction along the line CC) is used. The width of the opening 362a of the solar cell substrate holder 306 is made narrower than the width of the substrate 9, and the opening of the solar cell substrate holder 306 in the second direction along the surface 9a of the substrate 9 (direction along the DD line). The width of the portion 362 a is made equal to or wider than the width of the substrate 9. Thereby, a large film-forming area can be secured while the solar cell substrate holder 306 holds the substrate 9. As a result, since the effective area as a solar cell can be secured widely, cell conversion efficiency can be improved.

  Note that the shape of the opening 362ai of the solar cell substrate holder 362i in the solar cell substrate holder 306i may be fixed only at the corners of the substrate 9 as shown in FIG. That is, the opening 362ai connects the main side 362ai1 extending corresponding to the contour side of the substrate 9 and the two adjacent main sides 362ai1 and intersects the contour side of the substrate 9 in the vicinity of the corner of the substrate 9. And an inclined side portion 362ai2 extending in this manner. In this case, the area of the non-film formation region of the surface 9a covered with the solar cell substrate holder 362i can be further reduced, and the cell conversion efficiency can be further improved.

  Alternatively, as shown in FIG. 16, the opening 362aj of the solar cell substrate holder 362j in the solar cell substrate holder 306j may have a shape having claw-like projections. That is, the opening 362aj includes a main side 362aj1 extending corresponding to the contour side of the substrate 9, and a protrusion 362aj2 protruding from the main side 362aj1 to the inside of the opening 362aj. In this case, the area of the non-film formation region of the surface 9a covered with the solar cell substrate holder 362i can be further reduced, and the cell conversion efficiency can be further improved.

  Alternatively, as shown in FIG. 17, the substrate 9 may be fixed with the opening 362ak of the solar cell substrate holder 362k in the solar cell substrate holder 306k having a ladder shape. That is, the opening 362ak includes a main side 362ak1 extending corresponding to the contour side of the substrate 9, and a ladder part 36ak2 connecting the two main sides 362ak1 facing each other. In this case, the ladder portion 36ak2 may be provided so as to correspond to the current collecting electrode 17 to be formed on the substrate 9. For example, as shown in FIGS. 18 and 19, the collector electrode 17 is formed in a region (non-deposition region 19) covered with the ladder portion 36 ak2 (see FIG. 17) on the surface 9 a of the substrate 9. 18 is a plan view of the substrate 9 on which the current collecting electrode 17 is formed as viewed from the surface 9a side. FIG. 19 is a cross-sectional view of the substrate 9 of FIG. 18 taken along the line EE. FIG. As shown in FIG. 19, the collector electrode 17 is formed above the non-deposition region 19 where the i-type amorphous silicon layer 14 and the p-type amorphous silicon layer 15 on the surface 9a side of the substrate 9 are not formed. Is done. That is, since the substrate part under the non-deposition region 19 that hardly functions as a solar cell serves as a shadow part of the current collecting electrode 17, the sunlight does not substantially enter, so the effective area as a solar cell does not decrease. In other words, an effective area as a solar cell can be secured, and materials used for forming the i-type amorphous silicon layer 14 and the p-type amorphous silicon layer 15 can be saved.

A transparent conductive layer 18 made of an oxide conductor such as indium tin oxide (ITO) or zinc oxide (ZnO ₂ ) is formed on the i-type amorphous silicon layer 14 and the p-type amorphous silicon layer 15. Therefore, since the electric charge generated in the substrate 9 is transported to the current collecting electrode 17 through the transparent conductive layer 18, even if the non-film formation region 19 and the current collecting electrode 17 are in contact with each other, the connection resistance is reduced. The increase in solar cell conversion efficiency does not decrease.

  Further, since no leakage current is generated unless the p-type amorphous silicon layer 15 and the n-type amorphous silicon layer 16 are in contact with each other at the end surface portion of the substrate 9, no film is formed on the entire periphery of the back surface 9b of the substrate 9. It is not always necessary to provide a region. For example, as shown in FIG. 20, the counterbore part 361bp of the solar cell substrate tray 361p in the solar cell substrate holder 306p is provided on a pair of side edge portions orthogonal to the GG line, and a pair of sides orthogonal to the FF line As shown in FIG. 21, the opening 362ap of the solar cell substrate holder 362 in the solar cell substrate holder 306p is narrower in the HH direction than the substrate 9 as shown in FIG. The width may be the same as that of the substrate 9 or wider than the substrate 9. FIG. 20 is a plan view showing the configuration of the solar cell substrate holder 306p in a state where the solar cell substrate tray 361p is prepared and the substrate 9 and the solar cell substrate holder 362p are not yet placed. FIG. 21 is a plan view showing the configuration of the solar cell substrate holder 306p in a state where the substrate 9 is placed on the solar cell substrate tray 61 and the solar cell substrate holder 362p is further placed and the substrate 9 is fixed.

  In this case, a diagram showing a cross section when the solar cell substrate holder 362p and the solar cell substrate tray 361p shown in FIG. 21 are cut along the line HH is as shown in FIG. 22, and the solar cell substrate shown in FIG. FIG. 23 shows a cross-sectional view when the presser 362p and the solar cell substrate tray 361p are cut along the line II. 22 and 23, the surface 9a of the substrate 9 is in contact with the solar cell substrate holder 362p at a pair of edge portions orthogonal to the HH line, and the back surface 9b of the substrate 9 is orthogonal to the II line. Since the substrate 9 is fixed in contact with the solar cell substrate tray 361p at a pair of edges, the non-deposition region on the surface 9a of the substrate 9 when seen through from the direction perpendicular to the surface 9a of the substrate 9 The non-deposition region on the back surface 9 b of the substrate 9 extends so as to complement the periphery of the substrate 9 in a complementary manner. This makes it difficult for the p-type amorphous silicon layer 15 and the n-type amorphous silicon layer 16 to contact each other at the end face.

Embodiment 4 FIG.
Next, a solar cell manufacturing apparatus according to Embodiment 4 will be described with reference to FIG. FIG. 24 is a partial cross-sectional view of a film forming chamber constituting the solar cell manufacturing apparatus according to the fourth embodiment. Below, it demonstrates focusing on a different point from Embodiment 1 and Embodiment 2. FIG.

  In the first and second embodiments, the anode electrode 8 is heated by a heater to control the temperature of the substrate 9. In the fourth embodiment, a process gas having a predetermined temperature is not formed on the substrate 9. The temperature of the substrate 9 is controlled by supplying the film surface.

  Specifically, each film formation chamber (the first film formation chamber 21, the second film formation chamber 22, the third film formation chamber 23, and the fourth film formation chamber 24) has a process gas control system (first process gas). In addition to the control system 11, a process control system (second process gas control system) 412, a process control system (third process gas control system) 413, and a switching unit 414 are provided. The process gas control system 11 supplies process gas (first gas or second gas) to the film forming chamber through the opening 7 a of the cathode electrode 7, as in the first embodiment.

On the other hand, the process control system 412 supplies a process gas (third gas) through the opening 8 a of the anode electrode 8. The process control system 413 supplies process gas (fourth gas) through the opening 8 b of the anode electrode 8. The process gas supplied from the process gas control systems 412 and 413 includes, for example, a silicon-containing gas such as silane gas or an element serving as a dopant such as phosphorus (P) boron (B) such as PH ₃ or B ₂ H ₆ gas. The gas containing hydrogen, carbon dioxide, a noble gas, or the like alone or a combination thereof is used. That is, as the process gas supplied from the process gas control systems 412 and 413, any single gas of a gas type that cannot form a film or a mixed gas thereof is used. Since these process gases are supplied from the non-film formation side of the substrate 9 into the film formation chamber through the solar cell substrate tray 61, the solar cell substrate retainer 62, and the gaps of the substrate 9, they are generated in the film formation chamber. It is possible to suppress the deposition reaction species such as SiH _x radicals and the dopant gas such as PH ₃ and B ₂ H _{6 from} entering the non-deposition surface side.

  In addition, the process gases supplied from the process gas control systems 412 and 413 have different temperatures. For example, the temperature of the process gas supplied from the process gas control system 412 is lower than the temperature of the process gas supplied from the process gas control system 413.

  Then, the switching unit 414 performs switching so that one of the second process gas control system 412 and the third process gas control system 413 operates according to the temperature of the substrate 9 to be controlled. For example, when the temperature of the substrate 9 to be controlled is close to the temperature of the process gas supplied from the process gas control system 412, the switching unit 414 switches and controls the second process gas control system 412 to operate. When the temperature 9 is close to the temperature of the process gas supplied from the process gas control system 413, the third process gas control system 413 is switched to operate.

  Next, a film forming procedure will be described. First, low temperature hydrogen gas is supplied from the process gas control system 412 to control the temperature of the substrate 9 to be in the range of 100 to 150 ° C. In this state, a mixed gas of silane and hydrogen is supplied from the process gas control system 11 through the cathode electrode 7. The total amount of hydrogen gas supplied from the process gas control systems 11 and 412 is set to be in the range of 1 to 20 times the silane gas flow rate. Then, the process gas is discharged by supplying high-frequency power to the cathode electrode 7 to start the formation of the i-type amorphous silicon layer. Then, the process gas control system is switched from 412 to 413 during film formation, and the temperature of the substrate 9 is heated to a range of 150 to 200 ° C. by supplying high-temperature hydrogen gas to the non-film formation surface side of the substrate 9. Then, the i-type amorphous silicon layer is continuously formed to form an i-type amorphous silicon layer having a total film thickness of 2 to 10 nm.

  As a result, an i-type amorphous silicon layer in which epitaxial growth is sufficiently suppressed is formed at a relatively low temperature at the interface portion of the silicon substrate where there is a strong tendency to grow epitaxially, and the film forming temperature is immediately increased. Thus, it is possible to continuously form a higher quality i-type amorphous silicon layer with fewer defects in the film. Here, the high-quality i-type amorphous silicon layer has a hydrogen atom density in the range of 10 to 20% calculated from Fourier transform infrared absorption spectroscopy (FTIR), and SiH2 with respect to SiH bonds. It is defined as a bond ratio of 1/10 or less.

  Although not shown in FIG. 24, the anode electrode 8 itself may be provided with a temperature control mechanism by providing a heater electrode or the like in the anode electrode 8.

  In addition, regarding the method for controlling the temperature of the process gas supplied to the non-film-forming surface side of the substrate 9 during film formation, instead of switching the supply of process gas at different temperatures, the process gas is heated as shown in FIG. This may be done by providing a heating mechanism that changes the heating temperature. That is, each film forming chamber (the first film forming chamber 21, the second film forming chamber 22, the third film forming chamber 23, and the fourth film forming chamber 24) includes a process gas control system 412, a process gas control system 413, and Instead of the switching unit 414, a process gas control system 415i may be included. The process gas control system 415i includes a control system main body 415i1 and a heating mechanism 415i2. The process gas control system 415i supplies the process gas from the control system main body 415i1 to the heating mechanism 415i2 and heats it to a predetermined temperature by the heating mechanism 415i2, and the heated process gas is passed through the opening 8a of the anode electrode 8. The substrate 9 is supplied to the film formation chamber from the non-film formation surface side. For example, when the silicon substrate interface is formed, an i-type amorphous silicon layer in which epitaxial growth is sufficiently suppressed is formed by supplying a relatively low temperature process gas that is not heated by stopping the heating mechanism 415i2. After that, by operating the heating mechanism 415i2 to perform heating, a high-temperature process gas can be supplied to increase the temperature of the silicon substrate.

  Further, as shown in FIG. 26, a process gas exhaust system 416j for exhausting the process gas from the non-film-forming surface side of the substrate 9 through the opening 8c of the anode electrode 8 is provided for the configuration shown in FIG. Thus, the process gas supplied to the non-film-forming surface side of the substrate 9 may be circulated. By applying this structure, since the temperature of the substrate 9 is controlled, it is possible to supply a gas having a flow rate larger than that required for film formation on the non-film formation surface side. Can be performed more easily.

  Alternatively, as shown in FIG. 27, a process gas exhaust system 416j for exhausting the process gas from the non-film-forming surface side of the substrate 9 through the opening 8c of the anode electrode 8 is provided for the configuration shown in FIG. Thus, the process gas supplied to the non-film-forming surface side of the substrate 9 may be circulated. By applying this structure, since the temperature of the substrate 9 is controlled, it is possible to supply a gas having a flow rate larger than that required for film formation on the non-film formation surface side. Can be performed more easily.

  In the fourth embodiment, the film formation of the i-type amorphous silicon layer has been described. However, the present invention is applied to p-type and n-type amorphous silicon layers and p-type and n-type microcrystalline silicon layers. For example, during film formation, a low-temperature gas is supplied from the process gas control system 412 to the back surface 9b of the substrate 9 to lower the temperature of the substrate 9, thereby controlling the band gap by increasing the density of hydrogen atoms in the film. Then, it may be used for improving the bonding characteristics with the electrode material or the like.

  As described above, the solar cell manufacturing apparatus and the solar cell manufacturing method according to the present invention are useful for manufacturing a heterojunction solar cell.

  1, 201-1, 201-2 load chamber, 3,203 moving chamber, 4 unload chamber, 5-1 to 5-6, 5-11 to 5-16, 5-21 to 5-26 gate valve, 6 , 6-1,6-2 Solar cell substrate holder, 7 cathode electrode, 8 anode electrode, 9 substrate, 10 high frequency power source, 11, 412, 413, 415i process gas control system, 14 i-type amorphous silicon layer, 15 p-type amorphous silicon layer, 16 n-type amorphous silicon layer, 17 collector electrode, 18 transparent conductive layer, 19 non-deposition region, 21221-1, 211-2 first deposition chamber, 22, 222-1, 222-2 second film forming chamber, 23, 223-1, 223-2 third film forming chamber, 24, 224-1, 224-2 fourth film forming chamber, 30, 230 transport mechanism, 31 , 231 First transfer Structure, 32,232 second transport mechanism, 33,233 third transport mechanism, 61 solar cell substrate tray, 62 solar cell substrate holder, 100,200 manufacturing apparatus, 234 fourth transport mechanism, 235 fifth transport mechanism, 414 switching Part, 415i1 control system main body, 415i2 heating mechanism, 416j exhaust system.

Claims (18)

A plurality of the first main surface and the second main surface of the substrate having a first main surface and a second main surface opposite to the first main surface are exposed. A substrate holder for holding the substrate planarly;
When the substrate holder is loaded on the anode electrode side, the substrate holder comes into contact with the anode electrode, and the second main surface is isolated from the discharge to be generated, and the first main surface is The substrate holder is placed so as to be exposed to the discharge to be generated, and a high frequency power is applied between the cathode electrode and the anode electrode to discharge the first gas, thereby discharging the first gas on the substrate. A pre-deposition chamber for depositing a first film on one main surface;
When the substrate holder is loaded on the anode electrode side, the substrate holder comes into contact with the anode electrode, and the first main surface is isolated from the discharge to be generated, and the second main surface is The substrate holder is placed so as to be exposed to the discharge, and the second main surface of the substrate is discharged by applying a high frequency power between the cathode electrode and the anode electrode to discharge the second gas. A film formation chamber after forming a second film on
A transport mechanism for transporting the substrate holder in a direction along the first main surface in most of the transport path without opening the atmosphere from the pre-deposition chamber to the post-deposition chamber;
An apparatus for manufacturing a solar cell, comprising: The positional relationship between the cathode electrode and the anode electrode in the pre-deposition chamber is opposite to the positional relationship between the cathode electrode and the anode electrode in the post-deposition chamber. Solar cell manufacturing equipment. The transfer mechanism moves the substrate holder from the pre-deposition chamber to the transfer chamber connecting the pre-deposition chamber and the post-deposition chamber along the first main surface of the substrate. The substrate holder is moved from the position corresponding to the anode electrode of the pre-deposition chamber to the position corresponding to the anode electrode of the post-deposition chamber in the moving chamber. And moving the substrate holder from the moving chamber to the post-deposition chamber along the first main surface in the direction along the first main surface. The manufacturing apparatus of the solar cell of Claim 2. 4. The solar cell manufacturing apparatus according to claim 3, wherein the moving chamber connects the front film formation chamber and the rear film formation chamber in a direction along the first main surface of the substrate. . The solar cell manufacturing apparatus according to claim 3, wherein the moving chamber connects the front film formation chamber and the rear film formation chamber in a direction intersecting the first main surface of the substrate. . Both the first main surface and the second main surface of the second substrate having the first main surface and the second main surface opposite to the first main surface are exposed. A second substrate holder for holding the second substrate;
When the second substrate holder is carried into the anode electrode side, the substrate holder comes into contact with the anode electrode, and the second main surface is isolated from the discharge to be generated, and the first main holder is isolated. The substrate holder is placed so that the surface is exposed to the discharge to be generated, and the first gas is discharged by applying high-frequency power between the cathode electrode and the anode electrode. A second pre-deposition chamber for depositing a first film on the first main surface of the second substrate;
When the second substrate holder is carried into the anode electrode side, the substrate holder comes into contact with the anode electrode, and the first main surface is isolated from the discharge to be generated, and the second main holder is isolated. The substrate holder is placed so that the surface is exposed to the discharge, and the second gas is discharged by applying high-frequency power between the cathode electrode and the anode electrode to discharge the second gas. A second post-deposition chamber for forming a second film on the second main surface of
The second substrate holder is transferred from the second pre-deposition chamber to the second post-deposition chamber in the direction along the first main surface in most of the transfer path without opening to the atmosphere. Two transport mechanisms;
Further comprising
The positional relationship between the cathode electrode and the anode electrode in the second pre-deposition chamber is opposite to the positional relationship between the cathode electrode and the anode electrode in the second post-deposition chamber,
The moving chamber connects the front film formation chamber and the rear film formation chamber in a direction intersecting the first main surface of the substrate and intersects the opposite side of the substrate from the first main surface. The solar cell manufacturing apparatus according to claim 5, wherein the second pre-deposition chamber and the second post-deposition chamber are connected in a direction in which the second pre-deposition chamber is connected. The second transport mechanism moves the second substrate holder along the first main surface of the substrate from the second pre-deposition chamber to the transfer chamber along the first main surface. And moving the second substrate holder from the position corresponding to the anode electrode of the second pre-deposition chamber to the position corresponding to the anode electrode of the second post-deposition chamber in the moving chamber. The first main surface is moved in a direction intersecting the first main surface, and the second main body holder is moved from the moving chamber to the second post-deposition chamber along the first main surface of the substrate. It conveys in the direction along the surface. The manufacturing apparatus of the solar cell of Claim 6 characterized by the above-mentioned. The substrate holder has a substrate tray and a substrate holder,
The substrate tray and the substrate press hold the substrate by sandwiching in contact with the substrate, respectively.
The contact portion between the substrate and the substrate tray or the substrate retainer is selected so that the semiconductor layer formed on both surfaces of the substrate does not contact the substrate tray and the substrate retainer at the end surface portion, and the semiconductor layer is selected. The solar cell manufacturing apparatus according to any one of claims 1 to 7, wherein the solar cell manufacturing apparatus is disposed so as to be provided with a region that is masked and not formed. A first process gas control system for supplying the first gas or the second gas to the pre-deposition chamber and the post-deposition chamber via the cathode electrode;
A second process gas control system for supplying a third gas from the non-film-forming surface side of the substrate to the pre-deposition chamber and the post-deposition chamber via the anode electrode;
A third gas is supplied from the non-film-forming surface side of the substrate to the pre-film formation chamber and the post-film formation chamber through the anode electrode, with a fourth gas having a temperature different from that of the third gas. A process gas control system of
A switching unit configured to switch so that one of the second process gas control system and the third process gas control system operates according to the temperature of the substrate to be controlled;
Further equipped with,
The solar cell manufacturing apparatus according to any one of claims 1 to 8, wherein the apparatus is a solar cell manufacturing apparatus. An exhaust system for exhausting the third gas and the fourth gas through the anode electrode;
The solar cell manufacturing apparatus according to claim 9. A first process gas control system for supplying the first gas to the pre-deposition chamber via the cathode electrode and supplying the second gas to the post-deposition chamber via the cathode electrode;
And a third gas heated by the heating mechanism to each of the pre-deposition chamber and the post-deposition chamber from the non-deposition surface side of the substrate via the anode electrode. A fourth process gas control system to supply;
Further equipped with,
The solar cell manufacturing apparatus according to any one of claims 1 to 8, wherein the apparatus is a solar cell manufacturing apparatus. An exhaust system for exhausting the third gas and the fourth gas through the anode electrode;
The solar cell manufacturing apparatus according to claim 11. A solar cell manufactured using the solar cell manufacturing apparatus according to claim 8,
A collector electrode disposed in a first region corresponding to a contact portion between the substrate and the substrate tray or the substrate holder;
A semiconductor layer disposed in a second region remaining on the surface except for the first region;
A solar cell comprising: A plurality of the first main surface and the second main surface of the substrate having a first main surface and a second main surface opposite to the first main surface are exposed. A solar cell manufacturing method for manufacturing a solar cell including the substrate using a substrate holder that holds the substrate in a plane,
A loading step of loading the substrate holder to the anode electrode side in the pre-deposition chamber;
The substrate is in contact with the anode electrode so that the second main surface is isolated from the discharge to be generated and the first main surface is exposed to the discharge to be generated. A holder is placed on the first main surface of the loaded substrate by applying a high frequency power between the cathode electrode and the anode electrode in the pre-deposition chamber to discharge the first gas. A first film forming step of forming a first film;
A transport step of transporting the substrate holder from the anode electrode side in the pre-deposition chamber to the anode electrode side in the post-deposition chamber without opening to the atmosphere;
The substrate holder is placed so that the substrate holder contacts the anode electrode, and the first main surface is isolated from the discharge to be generated and the second main surface is exposed to the discharge. Then, a second film is formed on the second main surface of the substrate by applying a bias between the cathode electrode and the anode electrode in the post-deposition chamber to discharge the second gas. A second film forming step;
With
The positional relationship between the cathode electrode and the anode electrode in the pre-deposition chamber is opposite to the positional relationship between the cathode electrode and the anode electrode in the post-deposition chamber. . The conveying step is
An unloading step of unloading the substrate holder from the pre-deposition chamber in a direction along the first main surface along the first main surface of the substrate;
After the unloading step, a position corresponding to the anode electrode in the post-deposition chamber from a position corresponding to the anode electrode in the pre-deposition chamber along a direction substantially perpendicular to the first main surface of the substrate A moving step of moving the substrate holder to
A carrying-in step of carrying the substrate holder along the first main surface of the substrate into the post-deposition chamber in the direction along the first main surface after the moving step;
The method for manufacturing a solar cell according to claim 14, comprising: The substrate holder has a substrate tray and a substrate holder,
The substrate tray and the substrate press hold the substrate by sandwiching in contact with the substrate, respectively.
In the first film forming step or the second film forming step, a contact portion between the substrate and the substrate tray or the substrate presser is formed, and a semiconductor layer formed on both surfaces of the substrate is an end surface portion. 16. The method according to claim 14, wherein the step is performed so that a region that does not contact the tray and the substrate pressing member and is selectively formed by masking the semiconductor layer is provided. A method for manufacturing a solar cell. In the first film formation step, the first gas is supplied to the pre-film formation chamber through the cathode electrode,
In the second film formation step, the second gas is supplied to the post film formation chamber via the cathode electrode,
In each of the first film forming step and the second film forming step,
A first operation for supplying a third gas from the non-film-forming surface side of the substrate through the anode electrode and a fourth gas having a temperature different from that of the third gas through the anode electrode are supplied to the substrate. 17. The method according to claim 14, wherein either one of the second operation supplied from the non-film-forming surface side is switched according to the temperature of the substrate to be controlled. A method for manufacturing a solar cell. In the first film formation step, the first gas is supplied to the pre-film formation chamber through the cathode electrode,
In the second film formation step, the second gas is supplied to the post film formation chamber via the cathode electrode,
In each of the first film forming step and the second film forming step,
The solar cell production according to any one of claims 14 to 16, wherein the third gas is heated by a heating mechanism through the anode electrode and supplied from the non-film-forming surface side of the substrate. Method.

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