JP2012158815A - Method for treating polysilanes - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for safely treating polysilanes formed as by-products when a microcrystalline silicon film is formed by a CVD process.SOLUTION: Regarding the method for treating polysilanes, when a microcrystalline silicon film or an amorphous silicon film is deposited on a substrate by a plasma CVD process, polysilanes produced as by-products in a vacuum chamber, and deposited and stuck inside a vacuum pump are treated, wherein, an organic solvent selected from lubricating oils is poured and filled into the vacuum pump and is left for a prescribed time, next, the vacuum pump is dismantled, and the dismantled components stuck with the polysilane-dispersed organic solvent are cleaned with a cleaning oil.

Description

  The present invention relates to a method for treating polysilanes, and more particularly to a method for treating polysilanes formed as a by-product when a microcrystalline silicon film or an amorphous silicon film is formed by a CVD method.

  In recent years, solar cells have been in the spotlight as an energy source, and energy can be used efficiently, so that there is a remarkable spread. There are various types of solar cells. Among them, the single crystal Si type and the polycrystalline Si type occupy the majority, and the single crystal Si type solar cell (photoelectric conversion device) has energy per unit area. Excellent conversion efficiency.

  In addition to the conventional a-Si (amorphous silicon) type thin film solar cell, in recent years, an a-Si film and μc-Si (microcrystalline silicon) are stacked to improve conversion efficiency. Thin film solar cells have been developed. This is because microcrystalline Si has an extremely high electron mobility compared to amorphous Si.

  The Si thin film is formed by a plasma CVD method. Many conventional techniques are known as an apparatus for forming such a thin film. For example, a CVD apparatus intended to reduce manufacturing costs and maintenance costs has been proposed (for example, Patent Documents). 1).

  However, for example, when a microcrystalline Si film is formed, it is formed by a plasma CVD method using a silane gas. However, polysilanes are generated as by-products when the microcrystalline Si film is formed. The generated polysilanes are, for example, ultrafine powder having a particle size of about 37 nm, and are deposited and adhered to the inside of the apparatus or its inner wall, to the parts inside the apparatus, to the inside or the inner wall of exhaust pipes, or inside the vacuum pump. To do. Therefore, various measures are taken because there is a risk of dust explosion in the worst case depending on the state of the atmosphere.

  For example, since a large amount of polysilane is generated in the reaction vessel when forming an amorphous Si film, there is a risk of dust explosion when exhausting the reaction vessel suddenly. However, there is still a problem that the slow exhaust path is clogged, so it has been proposed to provide an inert gas introduction pipe in the slow exhaust path and to flow the inert gas through the slow exhaust path during slow exhaust (for example, Patent Document 2). However, even if the clogging of the slow exhaust path is prevented, there is a problem that the possibility of dust disaster does not disappear.

  Further, a switching means is provided between a reaction vessel for forming a deposited film on the object to be processed and an exhaust means for exhausting the inside of the reaction vessel, and this exhaust means is provided with an exhaust system for film deposition used for film deposition. , Having at least two exhaust systems for dry etching used for cleaning the reaction container, and configured to be able to switch the exhaust system during film deposition and during the cleaning of the reaction container. It has been proposed to capture by-products generated during film deposition using a powder trap provided between the two (see, for example, Patent Document 3). This patent document describes the use of an oil trap, but does not suggest what the oil is.

  However, as disclosed in Patent Document 3, even if a powder trap is provided between the reaction vessel and the switching means, the film is formed while evacuating, so that polysilanes formed over the entire path of the film formation process It is not always possible to treat all by-products such as, and there remains a risk of dust explosion due to polysilanes. Accordingly, there is a demand for more complete treatment of polysilanes.

JP 2005-139524 A Japanese Patent Laid-Open No. 08-283946 JP 2008-214660 A

  An object of the present invention is to solve the above-mentioned problems of the prior art, and in particular, safely treat polysilanes formed as by-products when forming a microcrystalline silicon film or an amorphous silicon film by a CVD method. It is to provide a way to do.

  The polysilanes processing method of the present invention is produced as a by-product in a vacuum chamber when a microcrystalline silicon film or an amorphous silicon film is deposited on a substrate by a plasma CVD method, and is deposited and adhered in a vacuum pump. Injecting and filling an organic solvent selected from a lubricating oil into the vacuum pump, leaving it for a predetermined time, then decomposing the vacuum pump, and depositing a polysilane-dispersed organic solvent The disassembled components are cleaned with cleaning oil.

  The polysilane treatment method of the present invention is also produced as a by-product in a vacuum chamber when a microcrystalline silicon film or an amorphous silicon film is deposited on a substrate by plasma CVD, and is installed in the vacuum chamber. A method of treating polysilanes deposited and adhering to a part being applied, wherein an organic solvent selected from a lubricating oil is applied to the part, and then a polysilane-dispersed organic solvent is placed in a sink containing cleaning oil. The adhering parts are put in and the parts are washed with cleaning oil.

  The polysilane treatment method of the present invention further generates a by-product in a vacuum chamber when a microcrystalline silicon film or an amorphous silicon film is deposited on a substrate by plasma CVD, Dispersing and processing polysilanes deposited in and attached to an organic solvent in an organic solvent, components disposed in a vacuum chamber, piping from the vacuum chamber to the vacuum exhaust system, and a vacuum pump of the vacuum exhaust system And

  The polysilane treatment method of the present invention is further provided by introducing a silane gas using a vacuum chamber on which a Si substrate is placed and equipped with a vacuum exhaust system, and then microcrystallizing the substrate by plasma CVD. When a silicon film or an amorphous silicon film is deposited, it is generated as a by-product in the vacuum chamber, and the components disposed in the vacuum chamber, the vacuum chamber, and piping from the vacuum chamber to the vacuum exhaust system The polysilanes deposited and adhered in the vacuum pump of the vacuum exhaust system are dispersed in an organic solvent and processed.

  According to the present invention, it is possible to safely treat polysilanes formed as by-products when forming a microcrystalline silicon film or an amorphous silicon film by a CVD method.

Sectional drawing for demonstrating one form of the manufacturing method of a photoelectric conversion apparatus. Sectional drawing for demonstrating another form of the manufacturing method of a photoelectric conversion apparatus. 2 is a photograph for explaining a treatment process of polysilanes in a vacuum pump in Example 1. FIG. 3 is a photograph showing the cleaning result of the component parts obtained in Example 1. FIG. 4 is a photograph for explaining a treatment process for polysilanes in a vacuum pump in Example 2. FIG. The photograph for demonstrating the processing process of the components to which polysilanes adhered in Example 3. FIG.

  According to the first embodiment of the method for treating polysilanes according to the present invention, this treatment method uses a film forming apparatus having a vacuum chamber on which a Si substrate is placed and equipped with a vacuum chamber equipped with a vacuum exhaust system. When a silane gas is introduced into the vacuum chamber and a microcrystalline silicon film and / or an amorphous silicon film is deposited on the Si substrate by plasma CVD, it is generated as a by-product in the vacuum chamber, and a vacuum exhaust system. A method of treating polysilanes deposited and adhering in a vacuum pump such as a dry pump, and an organic solvent selected from a lubricating oil such as mineral oil as described below into a vacuum pump removed from a vacuum chamber. Fill and fill, leave for a specified time, then disassemble the vacuum pump and disassemble the disassembled components with the polysilane dispersed lubricant attached as described below. It consists of cleaning an oil.

  According to the second embodiment of the method for treating polysilanes according to the present invention, this treatment method uses a film forming apparatus having an evacuable vacuum chamber on which a Si substrate is mounted and equipped with a vacuum exhaust system. When a microcrystalline silicon film and / or an amorphous silicon film is deposited on the Si substrate by plasma CVD method by introducing silane gas into the vacuum chamber, it is generated as a by-product in the vacuum chamber. Is a method for treating polysilanes deposited and adhering to various components (for example, transport trays, electrodes, etc. on which a substrate is placed and transported). An organic solvent selected from oil (for example, lubricating oil) or the like is applied (for example, the organic solvent is supplied into a vacuum chamber), and the part to which the polysilane-dispersed organic solvent is attached Extraction, then placed parts polysilane dispersed lubricating oil in the sink containing the cleaning oil as described below are attached, consists of cleaning the parts with washing oil. The piping can be treated by sink immersion as in the case of parts.

  According to the third embodiment of the method for treating polysilanes according to the present invention, this treatment method uses a film forming apparatus having a vacuum chamber on which a Si substrate is placed and equipped with a vacuum chamber equipped with a vacuum exhaust system. When a microcrystalline silicon film and / or an amorphous silicon film is deposited on the Si substrate by plasma CVD method by introducing silane gas into the vacuum chamber, it is generated as a by-product in the vacuum chamber. And the inner wall, the various parts arranged in the vacuum chamber, the exhaust pipe from the vacuum chamber to the vacuum exhaust system, the inner wall, and the polysilane deposited and adhered in the vacuum pump such as the dry pump of the vacuum exhaust system Is dispersed in an organic solvent selected from mineral oils as described below, and then washed with a cleaning oil as described below.

  Polysilanes as by-products as described above are used in solar cells, etc., using plasma CVD devices such as single wafer PE-CVD devices, in-line PE-CVD devices, and batch-type PE-CVD devices, for example. It is formed when the Si film (semiconductor layer) is formed.

  Hereinafter, an example of the plasma CVD apparatus will be described, and the treatment of the formed polysilanes will be referred to.

  As a first example of the plasma CVD apparatus, for example, a film forming chamber (vacuum chamber) for forming a desired film on a substrate in a vacuum, and a vacuum evacuation which is fixed to the film forming chamber via a first opening / closing part. A film forming apparatus having a possible loading / unloading chamber, a second opening / closing portion provided on a surface opposite to the first opening / closing portion of the loading / unloading chamber, and a film-forming surface of the substrate in a direction of gravity. A carrier that is held so as to be substantially parallel, the carrier or the substrate passes through the second opening / closing part and is carried into and out of the loading / unloading chamber, and a plurality of carriers are arranged in parallel in the loading / unloading chamber, A plurality of carriers are carried in and out in parallel between the loading / unloading chamber and the film forming chamber, and film formation is performed by simultaneously forming films on a plurality of substrates held by the plurality of carriers in the film forming chamber. For example, when a microcrystalline silicon film is formed on a substrate using an apparatus, microcrystalline silicon is used. Polysilanes are formed in large quantities at the time of forming the layer as a by-product.

  The polysilanes described above are deposited and adhered to the film forming chamber, its inner wall, and various parts installed in the film forming chamber, and are also deposited and adhered to the exhaust pipe and its inner wall. There is a high possibility that problems such as dust explosion and the like will occur, and countermeasures are required.

  In addition, as a second example of the plasma CVD apparatus, a film forming chamber (vacuum chamber) for forming a desired film on a substrate in a vacuum, and the film forming chamber are fixed via a first opening / closing part, Deposition with a evacuating preparation / removal chamber, and a substrate removal chamber for desorbing the substrate from a carrier configured to hold the substrate, which is fixed via the second opening / closing portion and the preparation / removal chamber. An apparatus, wherein the carrier holds the substrate so that the film formation surface is substantially parallel to the direction of gravity, and a plurality of carriers are arranged in parallel in the substrate removal chamber, and the substrate removal chamber, the loading / unloading chamber, Multiple carriers are loaded / unloaded in parallel, and multiple carriers are loaded / unloaded in parallel between the loading / unloading chamber and the deposition chamber, and are held by the multiple carriers in the deposition chamber. Using a film forming apparatus that forms films on a plurality of substrates at the same time, When forming a crystal silicon film, polysilanes as a by-product during the formation of the microcrystalline silicon layer is mass formed.

  Also in the case of the CVD apparatus of this second example, polysilanes are deposited and adhered to the film forming chamber, its inner wall and various parts installed in the film forming chamber, and are also deposited on the exhaust pipe and its inner wall. There is a high possibility that such a problem will occur due to adhering, depositing and adhering in the vacuum pump, and dust explosion as described above.

  Next, a case where a photoelectric conversion device used for a solar cell is manufactured by depositing the above-described microcrystalline silicon film or the like will be described with reference to WO2010 / 02947, and treatment of polysilanes generated as a by-product To mention.

  The first manufacturing system of this photoelectric conversion device is shown in FIG. As shown in FIG. 1, the first manufacturing system includes an in-line type first film forming apparatus (vacuum chamber) 60, a batch type second film forming apparatus (vacuum chamber) 70A, and a first film forming apparatus 60. The exposure apparatus 80A moves to the second film forming apparatus 70A after exposing the treated substrate such as a Si substrate to the atmosphere (air).

  The first film forming apparatus 60 in the first manufacturing system is provided with a load chamber (L) 61 into which a substrate is carried and the internal pressure is reduced. Note that a heating chamber for heating the substrate temperature to a certain temperature may be provided in the subsequent stage of the load chamber 61 in accordance with the film forming process.

  Subsequently, a p-layer film formation reaction chamber 62 for forming the p-type semiconductor layer of the first photoelectric conversion unit, an i-layer film formation reaction chamber 63 for forming an i-type silicon layer (amorphous silicon layer), and an n-type semiconductor layer An n-layer film formation reaction chamber 64 to be formed and a p-layer film formation reaction chamber 65 to form the p-type semiconductor layer of the second photoelectric conversion unit are continuously arranged in a straight line.

  Finally, an unload chamber (UL: unloading device) 66 for returning the decompressed atmosphere to the atmospheric atmosphere and unloading the substrate is connected to the p-layer film formation reaction chamber 65.

  As a result, a reduced pressure atmosphere is created between the load chamber 61, the p-layer film formation reaction chamber 62, the i-layer film formation reaction chamber 63, the n-layer film formation reaction chamber 64, the p-layer film formation reaction chamber 65, and the unload chamber 66. The substrate can be transported while being maintained.

  At this time, an insulating transparent substrate on which a transparent conductive film is formed is prepared at point A shown in FIG.

  Further, at the point B shown in FIG. 1, on the transparent conductive film, the p-type semiconductor layer, i-type silicon layer (amorphous silicon layer) and n-type semiconductor layer of the first photoelectric conversion unit, and the second A first intermediate product of the photoelectric conversion device provided with the p-type semiconductor layer of the photoelectric conversion unit is formed.

  Further, the exposure device 80A in the first manufacturing system is for temporarily placing or storing the first intermediate product in which the surface of the p-type semiconductor layer is exposed in the air atmosphere (air atmosphere). It is a shelf to use. Further, the exposure apparatus 80A may be a substrate storage cassette used for handling a plurality of first intermediate products as one group. Further, the exposure apparatus 80A may include a transport mechanism (atmospheric transport mechanism) that transports the first intermediate product from the first film forming apparatus 60 toward the second film forming apparatus 70A. When the first manufacturing system is operating in a clean room, the exposure device 80A exposes the first intermediate product in an air atmosphere in the clean room in which the humidity, temperature, or the amount of particles per unit volume is controlled. I am letting.

  Further, the second film forming apparatus 70 </ b> A in the first manufacturing system includes a load / unload chamber (L / UL) 71 and an in-layer film forming reaction chamber 72. This load / unload chamber carries in the first intermediate product of the photoelectric conversion device processed by the first film forming device 60, and when the substrate is carried in, the internal pressure is reduced, or when the substrate is carried out, It has a function of returning the reduced-pressure atmosphere to an air atmosphere. The in-layer film formation reaction chamber 72 is connected to the load / unload chamber 71.

  In the in-layer film formation reaction chamber 72, the i-type silicon layer (crystalline silicon layer) and the n-type semiconductor layer of the second photoelectric conversion unit are sequentially placed on the p-type semiconductor layer of the second photoelectric conversion unit. Formed with.

  Further, this film forming process is performed simultaneously on a plurality of substrates.

  At this time, the second intermediate product of the photoelectric conversion device provided with the second photoelectric conversion unit is formed on the first photoelectric conversion unit at the point C shown in FIG.

  In addition, as shown in FIG. 1, in the in-line type first film forming apparatus 60, film forming processing is simultaneously performed on two substrates, and the i-layer film forming reaction chamber 63 includes four reaction chambers 63a and 63b. , 63c, 63d.

  In FIG. 1, the batch-type second film forming apparatus 70 </ b> A is configured to simultaneously process six substrates.

  As described above, after the amorphous silicon pin power generation layer and the microcrystalline silicon p layer are formed in the in-line type first film formation apparatus (CVD apparatus: vacuum chamber) 60, the batch type second film formation apparatus ( In-layer of microcrystalline silicon is formed in a CVD apparatus (vacuum chamber) 70A. When the microcrystalline silicon layer is formed, particularly when the microcrystalline silicon layer is formed in a batch type CVD apparatus, a large amount of polysilanes are formed as by-products. These polysilanes deposit and adhere to the film forming apparatus (vacuum chamber), its inner wall and various parts installed in the film forming apparatus, and also deposit and adhere to the exhaust pipe and its inner wall. Therefore, it is highly possible that problems such as the above-mentioned dust explosion will occur due to accumulation and adhesion in the vacuum pump. In the case of an in-line type apparatus, since polysilanes are formed as a by-product, there may be a problem similar to that in the case of a batch type CVD apparatus. . You may take measures with an inline device.

  Next, a second manufacturing system of the photoelectric conversion device is shown in FIG. As shown in FIG. 2, the second manufacturing system includes a first film forming apparatus (CVD apparatus: vacuum chamber) 60, a second film forming apparatus (CVD apparatus: vacuum chamber) 70B, and a first film forming apparatus 60. The exposure apparatus 80B moves to the second film forming apparatus 70B after exposing the processed substrate to the atmosphere (air).

  Similar to the first film forming apparatus 60 in the first manufacturing system, the first film forming apparatus 60 in the second manufacturing system includes a load chamber (L) 61 that reduces the internal pressure after the substrate is loaded. Note that a heating chamber for heating the substrate temperature to a constant temperature may be provided in the subsequent stage of the load chamber 61 according to the process.

  Subsequently, a p-layer film formation reaction chamber 62 for forming the p-type semiconductor layer of the first photoelectric conversion unit, an i-layer film formation reaction chamber 63 for forming an i-type silicon layer (amorphous silicon layer), and an n-type semiconductor layer An n-layer film formation reaction chamber 64 to be formed and a p-layer film formation reaction chamber 65 to form the p-type semiconductor layer of the second photoelectric conversion unit are continuously arranged in a straight line.

  Finally, an unload chamber (UL) 66 for returning the reduced-pressure atmosphere to the atmospheric atmosphere and carrying out the substrate is connected to the p-layer film formation reaction chamber 65.

  As a result, a reduced pressure atmosphere is created between the load chamber 61, the p-layer film formation reaction chamber 62, the i-layer film formation reaction chamber 63, the n-layer film formation reaction chamber 64, the p-layer film formation reaction chamber 65, and the unload chamber 66. The substrate can be transported while being maintained.

  At this time, an insulating transparent substrate on which a transparent conductive film is formed is prepared at point D shown in FIG.

  In addition, at the point E shown in FIG. 2, the p-type semiconductor layer, i-type silicon layer (amorphous silicon layer) and n-type semiconductor layer of the first photoelectric conversion unit on the transparent conductive film, and the second photoelectric conversion. A first intermediate product of the photoelectric conversion device provided with each layer of the p-type semiconductor layer of the unit is formed.

  The configuration of the exposure apparatus 80B in the second manufacturing system is the same as the exposure apparatus 80A in the first manufacturing system. The exposure apparatus 80B may include a transport mechanism (atmospheric transport mechanism) that transports the first intermediate product from the first film forming apparatus 60 to the second film forming apparatus 70B in an air atmosphere.

  The second film forming apparatus 70B in the second manufacturing system includes a load / unload chamber 73, an i-layer film forming reaction chamber 74, an n-layer film forming reaction chamber 75, and an intermediate chamber 77 arranged in an annular shape.

  The load / unload chamber 73 reduces the internal pressure after the first intermediate product of the photoelectric conversion apparatus processed by the first film forming apparatus 60 is carried in, or changes the reduced pressure atmosphere to the air atmosphere when carrying out the substrate. To return.

  Subsequently, the substrate is carried into the intermediate chamber 77 through the load / unload chamber 73. Further, the intermediate chamber 77 and the i-layer film formation reaction chamber 74 are transported between the intermediate chamber 77 and the n-layer film formation reaction chamber 75.

  In the i-layer film formation reaction chamber 74, the i-type silicon layer (crystalline silicon layer) of the second photoelectric conversion unit is formed on the p-type semiconductor layer of the second photoelectric conversion unit. In the n-layer deposition reaction chamber 75, an n-type semiconductor layer is formed on the i-type silicon layer (crystalline silicon layer).

  In each of the i-layer deposition reaction chamber 74 and the n-layer deposition reaction chamber 75, one of the i-type silicon layer and the n-type semiconductor layer is formed on a single substrate.

  Further, a transfer device (not shown) provided in the intermediate chamber 77 transfers a substrate to each of the reaction chambers 74 and 75 in order to stack an i-type silicon layer and an n-type semiconductor layer, Or unload the board.

  Note that the second film forming apparatus 70B may include a heating chamber that heats the substrate temperature to a certain temperature according to the film forming process.

  At this time, a second intermediate product of the photoelectric conversion device in which the second photoelectric conversion unit is provided on the first photoelectric conversion unit is formed at point F shown in FIG.

  In FIG. 2, in the in-line type first film forming apparatus 60, film formation processing is simultaneously performed on two substrates, and the i-layer film formation reaction chamber 63 includes four reaction chambers 63 a, 63 b, 63 c, 63d.

  In FIG. 2, in the single wafer type second film forming apparatus 70B, seven substrates are simultaneously processed in each reaction chamber.

  In FIG. 2, the i-layer film formation reaction chamber 74 includes six reaction chambers 74a, 74b, 74c, 74d, 74e, and 74f.

  Since the i-type silicon layer constituting the second photoelectric conversion unit has a larger film thickness than the n-type semiconductor layer, the film formation time is longer than when the n-type semiconductor layer is formed.

  Therefore, the throughput for producing the photoelectric conversion device is determined depending on the number of reaction chambers in the i-layer film formation reaction chamber 74.

  As described above, in the single-wafer type second film forming apparatus 70B, the i-layer film forming reaction chamber 74 has six reaction chambers, so that an i-type silicon layer can be simultaneously formed on a plurality of substrates. This increases the throughput.

  According to the method for manufacturing a photoelectric conversion device as described above, crystalline photoelectric conversion is performed on the p layer, i layer, and n layer of the first photoelectric conversion unit that is an amorphous photoelectric conversion device in the first film forming device 60. The p layer of the 2nd photoelectric conversion unit which is an apparatus is formed. In the second film forming apparatuses 70A and 70B, the i layer and the n layer of the second photoelectric conversion unit are formed. Thereby, it is possible to easily control the crystallization rate distribution of the i layer of the second photoelectric conversion unit.

  In the above, when the i-type silicon layer (crystalline silicon layer) and the n-type semiconductor layer constituting the second photoelectric conversion unit are formed on the p-type semiconductor layer exposed to the atmosphere, this i layer is formed. It is desirable to expose the p layer of the second photoelectric conversion unit exposed to the atmosphere to plasma containing hydrogen radicals before forming (hydrogen radical plasma treatment).

  Examples of the hydrogen radical plasma treatment include a method in which a hydrogen radical plasma treatment chamber is prepared in advance, the substrate on which the p layer of the second photoelectric conversion unit is formed is transferred to the plasma treatment chamber, and the p layer is exposed to plasma. In addition, after the hydrogen radical plasma treatment, an i-type silicon layer (crystalline silicon layer) and an n-type semiconductor layer constituting the second photoelectric conversion unit are formed in separate reaction chambers.

  On the other hand, as the hydrogen radical plasma treatment, the hydrogen radical plasma treatment and the treatment for forming the i layer and the n layer of the second photoelectric conversion unit may be continuously performed in the same reaction chamber.

Here, when the process for forming the i layer and the n layer of the second photoelectric conversion unit and the hydrogen radical plasma process are performed in the same processing chamber, the inner wall of the reaction chamber is formed with hydrogen radicals before the i layer is formed. by exposure to a plasma containing, it can be removed by decomposing the residual impurity gas PH ₃ which is introduced when forming the last n-layer.

  Therefore, even when the film formation process of the i layer and the n layer of the second photoelectric conversion unit is repeatedly performed in the same processing chamber, a good impurity profile can be obtained, and a laminated thin film photoelectric conversion device with good power generation efficiency can be obtained. Can be obtained.

In the hydrogen radical plasma processing performed on the p layer of the second photoelectric conversion unit, using H ₂ gas (hydrogen gas) as the process gas when desired. That is, in order to generate hydrogen radical plasma, plasma is effectively generated by applying a high frequency such as 13.5 MHz, 27 MHz, 40 MHz, or the like between the electrodes in the processing chamber with H ₂ flowing into the processing chamber. Can be generated.

Further, in the above-described second film forming apparatuses 70A and 70B, a gas box (gas introduction part) and a gas line (gas introduction part) for supplying H ₂ gas used for hydrogen radical plasma treatment into the treatment chamber (reaction chamber). Is provided. In addition, a mass flow controller (gas introduction unit) is connected to the processing chamber, the flow rate of H ₂ gas supplied through the gas box and the gas line is controlled, and a gas having a controlled flow rate is supplied into the processing chamber. The

  When hydrogen radical plasma treatment is performed in this manner, a mild reaction occurs as compared with O radicals, and therefore, there is an effect of activating the surface of the p layer of the second photoelectric conversion unit without damaging the lower layer.

  Therefore, the surface of the p layer of the second photoelectric conversion unit can be activated, and crystals of the i layer and the n layer of the second photoelectric conversion unit laminated thereon can be effectively generated. Even when the second photoelectric conversion unit is formed on a large-area substrate, a uniform crystallization rate distribution can be obtained.

  In addition, the n layer of the first photoelectric conversion unit and the p layer of the second photoelectric conversion unit may be a layer in which microcrystalline silicon (μc-Si) is dispersed in an amorphous silicon (a-Si) layer, A layer in which microcrystalline silicon (μc-Si) is dispersed in an amorphous silicon oxide (a-SiO) layer may be used.

  However, in order to obtain a uniform crystallization distribution rate required when the area of the substrate is increased, that is, a uniform crystallization distribution rate by generation of crystal growth nuclei of the crystalline photoelectric conversion layer i layer and n layer. For this, it is preferable to employ a layer in which microcrystalline silicon (μc-Si) is dispersed in an amorphous silicon oxide (a-SiO) layer.

  Thus, a layer in which microcrystalline silicon (μc-Si) is dispersed in an amorphous amorphous silicon oxide (a-SiO) layer has a lower refractive index than an amorphous silicon (a-Si) semiconductor layer. It is possible to adjust as follows.

  Therefore, it is possible to improve the conversion efficiency by making this layer function as a wavelength selective reflection film and confining short wavelength light on the top cell side.

  Regardless of the effect of confining the light, a layer in which microcrystalline silicon (μc-Si) is dispersed in an amorphous amorphous silicon oxide (a-SiO) layer is subjected to hydrogen radical plasma treatment. Generation of crystal growth nuclei of the i-layer and n-layer of the photoelectric conversion unit can be effectively performed, and a uniform crystallization rate distribution can be obtained even on a large-area substrate.

  In the present invention, a crystalline silicon-based thin film may be formed as the n layer constituting the first photoelectric conversion unit. That is, the n layer of microcrystalline silicon and the p layer of the second photoelectric conversion unit of microcrystalline silicon are formed on the p layer and i layer of the first photoelectric conversion unit of amorphous silicon.

  At this time, the p layer of the amorphous first photoelectric conversion unit, the amorphous i layer formed on the p layer, the crystalline n layer formed on the i layer, and the n layer It is desirable to form the p layer of the second photoelectric conversion unit formed in a continuous manner without opening to the atmosphere.

  In particular, in the method of forming the p layer, i layer, and n layer of the second photoelectric conversion unit in a separate reaction chamber after opening the p layer, i layer, and n layer of the first photoelectric conversion unit, and then opening the atmosphere. The i-layer of the first photoelectric conversion unit deteriorates due to the time, temperature, atmosphere, etc., when the substrate is left open to the atmosphere and the device performance deteriorates.

  Therefore, after forming the p layer and i layer of the first photoelectric conversion unit, the crystalline n layer and the p layer of the second photoelectric conversion unit are continuously formed without opening to the atmosphere.

  In this manner, the substrate on which the crystalline n layer and the p layer of the second photoelectric conversion unit are formed is subjected to hydrogen radical plasma treatment in an individual reaction chamber or the same reaction chamber, and the surface is activated to form crystal nuclei. By producing and subsequently laminating the i layer and the n layer of the crystalline second photoelectric conversion unit, a laminated thin film photoelectric conversion device with good power generation efficiency can be obtained.

  FIG. 2 shows an example in which each of the i layer and the n layer of the second photoelectric conversion unit is formed in individual reaction chambers 74 and 75. However, each of the individual reaction chambers 74 and 75 is shown in FIG. In this case, a method of continuously forming the i layer and the n layer may be employed.

  Also in the second manufacturing system described above, when forming the microcrystalline silicon layer (n layer, p layer), as in the case of the first manufacturing system, polysilanes are used as by-products when forming the microcrystalline silicon layer. Formed in large quantities. These polysilanes deposit and adhere to the inside of the equipment, its inner wall and various parts installed in the equipment, and also deposit and adhere to the exhaust pipe and its inner wall, and also deposit and adhere to the vacuum pump. However, since there is a high possibility that problems such as the dust explosion described above will occur, countermeasures are required.

  In the case of a plasma CVD apparatus that forms a known microcrystalline silicon film other than the above-described CVD apparatus, polysilanes may be formed as a by-product when the microcrystalline silicon film is formed, and the same problem as described above may occur. Of course, it is not necessary to argue that it is necessary to take similar measures.

  Next, a method for treating polysilanes formed as by-products when forming a microcrystalline silicon film or an amorphous silicon film will be described.

  In a technical field such as a solar cell, when a microcrystalline silicon film or an amorphous silicon film is formed using silane by a plasma CVD method, polysilanes are generated as a by-product in a vacuum chamber, and the polysilanes are generated in the chamber. It accumulates on and adheres to various parts installed in the chamber, its inner wall and chamber, and also deposits and adheres to the inside of exhaust pipes and its inner wall, and also deposits and adheres to the vacuum pump (dry pump). Thus, it is known that there is a risk of dust explosion at a predetermined concentration.

  According to the study of the present inventor, the dust explosion as described above occurs, for example, when the attached polysilanes are peeled off (collapsed) from the inner wall of the chamber due to the influence of an electrode or the like disposed in the vacuum chamber. It was found that the polysilanes were ignited by static electricity (collapse potential). In addition, polysilanes accumulated in piping and vacuum pumps (dry pumps, etc.) may explode due to static electricity as an ignition source. If polysilanes are deposited in the vacuum pump, the pump becomes inoperable, so an overhaul is required. However, there is a risk of explosion even during transportation to an overhaul factory or the like.

  Since it is dangerous to simply burn polysilanes, conventionally, as described above, the production of polysilanes is suppressed or trapped and removed, but there is no satisfactory solution. For example, even if it is treated with water or steam in order to eliminate the collapse potential, the problem is not solved because polysilanes are hydrophobic and thus difficult to completely wet with water. In addition, if water is present, hydrogen gas may be generated, which is dangerous in another sense.

  According to the study of the present inventor, in order to solve the above problems, for example, (1) a method of treating with an anionic, cationic and / or nonionic surfactant (aqueous), (2) mineral oil, etc. (3) A method of treating with an organic solvent containing mineral oil, (4) A method of treating with a perfume solvent (oil-based material) such as refined oil, And (5) Combustion method etc. can be considered.

  The treatment method (1) has the advantage that it can be made nonflammable with a single agent and has a low cost. However, if the surfactant is water-based, hydrogen gas is generated when the polysilane comes into contact with moisture, whether it is alkaline or acidic. Therefore, it cannot be said that there is no danger, and there is a disadvantage that it is expensive depending on the type of surfactant used. As the surfactant, those described above can be used, but nonionic surfactants having strong detergency due to less foaming and a small critical micelle concentration (CMC) are preferable.

  The treatment method (2) is advantageous in that non-combustible cleaning can be easily performed and the treatment of the surfactant waste liquid is easy, but the cost is high (the surfactant that cleans the oil is expensive), and the interface If the activator is water-based, when polysilanes come into contact with the moisture, hydrogen gas may be generated as described above.

  The treatment method (3) does not generate hydrogen, is low in cost, and can be used repeatedly. (Because polysilanes are aggregated and dispersed in the oil, filtration is possible. ), However, there are drawbacks in that two carrier oils / cleaning oils are required and waste oil treatment after cleaning is required.

  The treatment method (4) has the advantage that it can be cleaned with incombustibility with one agent and does not generate hydrogen, but it requires high cost, waste solvent treatment, and its flash point is near room temperature. There are difficulties.

  The processing method (5) has the disadvantage that the structure is complicated especially in the case of a vacuum pump (dry pump), so that it remains unburned and the operation is dangerous.

  In the above processing method, especially in the case of a vacuum pump, it is removed from the vacuum chamber and transported to an overhaul factory, where it is disassembled and cleaned, but there is a risk of explosion even during its transportation, so avoid such danger It is necessary to consider possible countermeasures.

  Therefore, for the treatment of polysilanes, the treatment methods (1) to (4) described above are possible, and the treatment method (3) is preferred in view of the recent increase in waste oil treatment plants.

  Hereinafter, the processing method (3) will be mainly described.

  Since the polysilanes to be produced are ultrafine powder having a particle size of about 37 nm, they are dispersed in an organic solvent including mineral oil.

  Therefore, the polysilanes deposited in the vacuum chamber and adhering to the inner wall thereof are peeled off by spraying an organic solvent, and the polysilanes dispersed in the organic solvent are taken out, transported, Process in place. That is, the polysilane-containing organic solvent is filtered, the polysilanes are removed, and the organic solvent is reused.

  Also, after removing the parts placed in the vacuum chamber, transport them by immersing them in an organic solvent such as mineral oil in a sink, etc., and disperse the polysilanes adhering to the parts at a predetermined place. The organic solvent is washed with washing oil. Also, the piping can be cleaned as in the case of parts.

  In addition, for vacuum pumps (dry pumps), remove from the vacuum chamber, open the inlet of the upper cylinder, inject and fill with organic solvent such as mineral oil, close the inlet, transport to the processing plant, etc. After being left for a predetermined time, it is decomposed, and the polysilane-dispersed organic solvent is washed with washing oil to overhaul. Then assemble and reuse.

Hereinafter, organic solvents such as mineral oil that can be used in the present invention will be described. Polysilanes are hydrophobic substances and can be dispersed in organic solvents. The organic solvent may be any organic solvent that does not generate hydrogen gas in a state where polysilanes are dispersed. For example, an organic solvent that does not contain water is preferable. Further, the flash point may be anything that does not ignite during the processing operation, preferably at room temperature or higher, for example, 40 to 45 ° C. or higher, and the kinematic viscosity is lower when considering the permeability into the vacuum pump. Preferably, for example, it may be 65 mm ² / s or less, preferably 40 mm ² / s or less at 40 ° C. Furthermore, it is preferable that this organic solvent does not have an unsaturated bond in the component. In addition, about a thing with a high viscosity, it can heat to predetermined temperature at the time of use, and can use it, reducing a viscosity.

  Examples of the organic solvent that can be used in the present invention include cyclohexanone, 4-hydroxyn-4-methyl-2-pentanone, 3,5,5-trimethyl-2-cycloxen-1-one, and 2,6-dimethyl. Ketone solvents such as -4-hebutanone; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono tert-butyl ether, ethylene glycol monobutyl ether, 3-methyl-3-methoxybutanol, diethylene glycol monobutyl ether, diisopropyl ether, di Ether solvents such as butyl ether, 1,2-dimethoxyethane, tetrahydrofuran, anisole, ethylene glycol monoethyl ether acetate; heavy aromatics (HA-100, HA- 50, HA-180), aromatic hydrocarbon solvents such as mesitylene, ethylbenzene, chlorobenzene and ortho-dichlorobenzene; aliphatic hydrocarbon solvents such as n-hexane, n-heptane, n-octane and decane; cyclo Alicyclic hydrocarbon solvents such as pentane, cyclohexane, cycloheptane, cyclooctane; dichloromethane, trichloroethylene, 1,1,2,2-tetrachloroethylene, 1,2-dichlorobenzene, chloroform, carbon tetrachloride, 1 Halogenated hydrocarbon solvents such as 1,2-dichloroethane; propylene glycol monomethyl ether acetate, celloselve acetate (ethylene glycol monoethyl ether acetate), ethyl-3-ethoxypropionate, 3-methoxybutyl acetate, 3-methyl-3 -Methoxy Ester solvents such as tilacetate; petroleum solvents such as coal tar, petroleum benzene, turpentine, and mineral spirits; silicon oils; paraffinic solvents such as liquid paraffin; N, N-dimethylformamide, 4-methylaminolactam, Examples thereof include a solvent such as dimethyl sulfoxide; an alcohol solvent; and a combination of two or more of these solvents. In addition, perfume oils, for example, a mixture of natural and synthetic fragrances, may be used as long as the object of the present invention can be achieved even if not mentioned above.

  Furthermore, although partially overlapping with the above, turbine oil, gear oil, spindle oil, lubricating oil, and the like used as machine oil can also be used.

  Examples of the lubricating oil include Daphne (registered trademark) oil and Daphne mechanic oils 32 and 46 (trade name) and Diana Fresia W-8 (trade name) manufactured by Idemitsu Kosan Co., Ltd., as well as Daphne mechanic oil and Diana. Base oil etc. from which additives are removed from Frescia etc. can be used. Also, Arboyl R-4, R-7, R-80 (manufactured by ULVAC, Inc .; trade name), which are petroleum mineral oils as pump oil for oil rotary vacuum pumps, and base oils thereof can be used.

  According to the present invention, the polysilane-dispersed organic solvent adhering to the above components, pipes and vacuum pump is washed with the washing oil.

  As this cleaning oil, it is only necessary to be able to wash the polysilane-dispersed organic solvent, and it can be used by appropriately selecting from the organic solvents described above. However, a lower kinematic viscosity is preferable. For example, paraffinic solvents are preferred. Specifically, for example, Daphne Alpha Cleaners M and H (trade names) manufactured by petroleum solvent Idemitsu Kosan Co., Ltd., and clean-through L841 (trade names) can be used.

  Embodiments of the present invention will be described below with reference to the drawings.

  Using a known plasma CVD apparatus, a silane gas was allowed to flow in a vacuum chamber under a known process condition, and a microcrystalline silicon film was formed on the Si substrate. As a by-product, a large amount of polysilanes were formed, and the vacuum pump A large amount was also deposited in the (dry pump). Therefore, the polysilanes in the vacuum pump were processed through the processes shown in FIGS.

  That is, the vacuum pump is removed from the vacuum chamber, the upper cylinder inlet is opened, and Dafney (registered trademark) mechanic oils 32 and 46 (trade name) made by Idemitsu Kosan Co., Ltd. are injected into the vacuum pump as lubricating oil. Then, after closing the intake port, transporting it to the processing plant, leaving it overnight, disassembling the vacuum pump, and using the polysilane-dispersed organic solvent adhering to each component as the cleaning oil, Idemitsu Kosan Co., Ltd. Washing was performed using Daphne Alpha Cleaner M and H (trade names) manufactured by the manufacturer.

  Since both the Daphne mechanic oils 32 and 46 as the lubricating oil used in this example and the Daphne alpha cleaners M and H as the cleaning oil obtained the same result, the Daphne mechanic oil 32 and The result when using Daphne Alpha Cleaner M will be described as a representative.

  FIG. 3 (a) shows a state where the upper cylinder inlet of the pump is opened when disassembling the vacuum pump at the processing plant (the brown one is polysilane dispersed lubricating oil), and FIG. 3 (b) shows The pump upper cylinder inlet port is wiped with a waste cloth, and FIGS. 3C to 3F show the state of each component after the pump is disassembled. That is, FIG. 3 (c) shows the state of polysilane dispersed lubricating oil adhering to the dry upper cylinder in the pump, and FIG. 3 (d) shows the state of polysilane dispersed lubricating oil adhering to the dry lower cylinder rotor in the pump. 3 (e) shows the state of the polysilane dispersed lubricating oil adhering to the dry rotor in the pump, and FIG. 3 (f) shows the state of the polysilane dispersed lubricating oil adhering to the dry lower cylinder in the pump. Show.

  As is apparent from FIGS. 3C to 3F, it can be seen that the polysilane-dispersed lubricating oil permeates and adheres to the entire components in the vacuum pump.

  Next, the component parts to which the polysilane-dispersed lubricating oil adhered were washed as described above. Among the components, a dry rotor is taken as an example, and the cleaning state is shown in FIGS. As is clear from FIGS. 4A to 4D, it can be seen that all the deposits are removed from the surface of the rotor, and a clean surface is obtained. It was confirmed that similar results were obtained with other components.

  In this way, each component which overhauled was assembled. Using this vacuum pump, a microcrystalline silicon film was formed on the Si substrate by plasma CVD as described above. The film formation process could be carried out in the same way as when using a new vacuum pump.

  The method described in Example 1 was repeated. However, polysilane deposited in the vacuum pump was treated using Daphne Mechanic Oil 68 as the lubricating oil and Daphne Alpha Cleaner M as the cleaning oil.

  The result is shown to Fig.5 (a)-(f). FIG. 5A shows a state in which lubricating oil is injected into the pump from the vacuum pump inlet port, and FIG. 5B shows a state in which the pump inlet port is opened after being left overnight after the lubricating oil injection. 5 (c) to 5 (f) show the state of each component (rotor, cylinder) after disassembling the pump, respectively.

  As is apparent from FIGS. 5C to 5F, it can be seen that the lubricating oil penetrates only up to the second stage of the vacuum pump. Even when the polysilane reaches only the second stage, it is considered that the treatment has been effected to some extent.

  When each component thus obtained was washed by the method described in Example 1, it could be washed cleanly and a clean surface was obtained.

  The method described in Example 1 was repeated. However, the polysilanes adhering to the components among the components installed in the vacuum chamber were processed.

  Introducing Daphne Mechanic Oil 32 as lubricating oil into the vacuum chamber, taking out the parts to which the polysilanes to which this oil was applied are taken out, and using the Daphne Alpha Cleaner M as the cleaning oil, the polysilanes adhering to the parts surface The dispersed lubricating oil was washed.

  As shown in FIG. 6, cleaning oil is injected into the sink (FIG. 6 (a)), and the part to which the polysilane-dispersed lubricating oil is attached is immersed in the sink (FIG. 6 (b)), and cleaning is performed in the sink. (FIG. 6C). As a result of this cleaning, the parts became clean (FIGS. 6D to 6F) and could be reused. Also, regarding the piping, a clean surface was obtained when treated in the same manner as the above parts.

  A microcrystalline silicon film was formed on the Si substrate using the plasma CVD apparatus of the first and second examples described above. A large amount of polysilanes are formed as a by-product during the formation of the microcrystalline silicon layer, and these polysilanes deposit and adhere to various components installed in the film formation chamber, its inner wall and film formation chamber, and exhaust piping. It deposited and adhered to the inside and its inner wall, and also deposited and adhered to the vacuum pump.

  When the formed polysilanes were treated according to the method described in Example 1, the polysilanes deposited and adhered in the vacuum pump were washed, and a pump component having a clean surface was obtained.

  A microcrystalline silicon film was formed on the Si substrate using the first and second manufacturing systems shown in FIGS. 1 and 2, respectively. A large amount of polysilanes are formed as a by-product during the formation of the microcrystalline silicon layer, and these polysilanes deposit and adhere to various components installed in the film formation chamber, its inner wall and film formation chamber, and exhaust piping. It deposited and adhered to the inside and its inner wall, and also deposited and adhered to the vacuum pump.

  When the formed polysilanes were treated according to the method described in Example 1, the polysilanes deposited and adhered in the vacuum pump were washed, and a pump component having a clean surface was obtained.

  According to the present invention, polysilanes formed as a by-product when a microcrystalline silicon film and / or an amorphous silicon film are formed by plasma CVD can be safely processed. Alternatively, the present invention can be effectively used in an industrial field using an amorphous silicon film, particularly in a solar cell industrial field.

60 first film forming apparatus 61 load chamber 62 layer film forming reaction chamber 63 layer film forming reaction chamber 63a, 63b, 63c, 63d reaction chamber 64, 65 layer film forming reaction chamber 66 unload chamber 70A, 70B second film forming apparatus 71 Load / unload chamber 72 Layer deposition reaction chamber 73 Load / unload chamber 74, 75 Reaction chamber 74a, 74b, 74c, 74d, 74f Reaction chamber 77 Intermediate chamber 80A, 80B Exposure equipment

Claims (4)

When depositing a microcrystalline silicon film or an amorphous silicon film on a substrate by plasma CVD, it is a method for treating polysilanes that are generated as by-products in a vacuum chamber and deposited and adhered in a vacuum pump. The organic solvent selected from the lubricating oil is injected and filled into the vacuum pump, left for a predetermined time, and then the vacuum pump is decomposed to clean the decomposed components to which the polysilane-dispersed organic solvent is adhered. A method for treating polysilanes, which comprises washing with oil. Polysilanes that are generated as by-products in a vacuum chamber when depositing a microcrystalline silicon film or an amorphous silicon film on a substrate by plasma CVD, and depositing and adhering to components installed in the vacuum chamber The organic solvent selected from the lubricating oil is applied to the part, and then the part to which the polysilane-dispersed organic solvent is adhered is placed in the sink containing the cleaning oil. A method for treating polysilanes, comprising washing with a washing oil. When a microcrystalline silicon film or an amorphous silicon film is deposited on a substrate by a plasma CVD method, it is generated as a by-product in a vacuum chamber, the vacuum chamber, a component disposed in the vacuum chamber, the vacuum A method for treating polysilanes, comprising: dispersing and treating polysilanes deposited and adhering in a pipe from a chamber to the vacuum exhaust system and in a vacuum pump of the vacuum exhaust system in an organic solvent. When a silane gas is introduced using a vacuum chamber capable of depressurization equipped with a vacuum exhaust system on which a Si substrate is placed, and a microcrystalline silicon film or an amorphous silicon film is deposited on the substrate by plasma CVD, Produced as a by-product in the vacuum chamber, and into the vacuum chamber, components disposed in the vacuum chamber, piping from the vacuum chamber to the vacuum exhaust system, and a vacuum pump of the vacuum exhaust system A method for treating polysilanes, characterized by dispersing and treating polysilanes deposited and adhered in an organic solvent.