JP2012114293A - Semiconductor film deposition apparatus and semiconductor film deposition method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor film deposition apparatus which can ensure good in-plane uniformity stably for a long term by preventing occurrence of internal leak in a deposition chamber due to particles produced in the deposition chamber, and to provide a semiconductor film deposition method.SOLUTION: The semiconductor film deposition apparatus comprises a deposition chamber 5, a carry-in/carry-out gate 15 provided on one sidewall of the deposition chamber 5 in order to carry a substrate 2 in the deposition chamber 5 or to carry out the substrate 2 therefrom, a conveyance chamber 20 capable of being decompressed which is connected to the deposition chamber 5 via the carry-in/carry-out gate 15 in order to carry the substrate 2 in the deposition chamber 5 or to carry out the substrate 2 therefrom, a freely opening/closing gate valve 10 which can hermetically close the deposition chamber 5 by closing the carry-in/carry-out gate 15 while sandwiching a seal material 11 over the whole circumference at the peripheral part of the carry-in/carry-out gate 15 on the side surface of one sidewall on the conveyance chamber 20 side, and a trap plate 9 arranged at the carry-in/carry-out gate 15 in order to capture particles 8 produced in the deposition chamber 5.

Description

  The present invention relates to a semiconductor film manufacturing apparatus and a semiconductor film manufacturing method, and more particularly to a semiconductor film manufacturing apparatus and a semiconductor film manufacturing method suitable for manufacturing a photoelectric conversion layer (semiconductor layer) of a thin film solar cell.

  Conventionally, a thin film solar cell has a tandem structure in which a plurality of photoelectric conversion layers (semiconductor layers) made of materials with different band gaps are stacked on a light-transmitting insulating substrate in order to effectively use the solar spectrum widely. Yes. In particular, in the case of a silicon-based thin film solar cell, a structure in which an amorphous silicon cell and a microcrystalline silicon cell are stacked is often employed as a semiconductor layer. Here, each cell has a three-layer structure in which a p-type semiconductor film, an i-type semiconductor film, and an n-type semiconductor film are sequentially stacked. The I-type semiconductor film is a power generation layer, the P-type semiconductor film, and the N-type semiconductor film are This is a layer for forming a built-in electric field.

  For example, in a microcrystalline silicon solar battery cell, a thick film having a thickness of 1 μm or more is applied as the i-type microcrystalline semiconductor film of the power generation layer. This is because the absorption coefficient of the microcrystalline semiconductor is lower than that of amorphous silicon, and a film thickness sufficient to obtain a necessary generated current is required. In general, when such a thick semiconductor film is formed, a large amount of excess film (residual film) is formed on the inner wall surface of the film forming chamber or the surface of the shower head in the film forming apparatus. When these residue films are peeled off, a large number of particles are generated and scattered over a wide area in the film forming chamber. If such particles reach the transfer gate between the film forming chamber and the transfer chamber and adhere to the O-ring surface of the gate valve, for example, they may bite into the open / close portion of the gate valve and cause internal leakage. is there.

  When such an internal leak occurs, the source gas supplied into the film forming chamber is drawn in the direction of the gate valve during the film forming process and flows in one direction. There is concern about causing sex. In the case of a thin film solar cell, in-plane non-uniformity of a semiconductor layer, particularly a power generation layer, is directly related to a decrease in power generation efficiency when modularized, and thus must be avoided.

  Further, the particles once adhering to the O-ring surface as described above cannot be removed even by cleaning the film forming chamber. For this reason, the only way to repair the O-ring surface is to stop the apparatus and perform maintenance of the gate valve. Therefore, if such internal leaks occur frequently, the downtime of the apparatus increases and productivity is reduced.

  For this reason, in a conventional semiconductor film deposition apparatus, a pipe for periodically injecting an inert gas is provided inside the gate valve, and a configuration that suppresses adhesion of particles to the opening and closing part of the gate valve. (For example, refer to Patent Document 1).

JP 2005-26516 A

  However, when the method of injecting an inert gas to the opening / closing part of the gate valve as in the technique of Patent Document 1, particles soar and enter the film forming chamber and adhere to the surface of the manufactured film. There was a risk of deteriorating physical properties.

  Moreover, a thin film solar cell is normally produced on the glass substrate whose one side length is 1 meter or more. For this reason, in the technique of Patent Document 1, the lateral width of the opening / closing part of the gate valve of the CVD apparatus is 1 meter or more, the area (O-ring surface) where the inert gas should be injected becomes enormous, and particle adhesion is not suppressed. There was also the problem of becoming perfect.

  In addition, when particles adhere to the O-ring surface of the gate valve and cause internal leaks. O-ring replacement work occurs. If the frequency of replacement increases, there is also a problem that the period during which the apparatus is stopped increases and productivity deteriorates.

  The present invention has been made in view of the above, and the occurrence of internal leakage in the film forming chamber due to particles generated in the film forming chamber is prevented, and good in-plane uniformity can be stably maintained over a long period of time. An object is to obtain a feasible semiconductor film manufacturing apparatus and semiconductor film manufacturing method.

  In order to solve the above-described problems and achieve the object, a semiconductor film manufacturing apparatus according to the present invention holds a substrate to be processed so that a film-forming surface is horizontal and upward, and an upper portion of the film-forming surface. A thin film is formed by generating a plasma of the raw material gas in a state in which the raw material gas is supplied toward the surface of the film to be deposited, decomposing the raw material gas by the plasma, and depositing it on the surface of the film to be formed A film-forming chamber that can be evacuated, a carry-in / out gate that is provided on one side wall of the film-forming chamber and carries the substrate into and out of the film-forming chamber, and the carry-in / out gate A transfer chamber that is connected to the film formation chamber via the substrate and is capable of depressurizing the substrate to be transferred into and out of the film formation chamber, and the loading / unloading on the side surface of the one side wall portion on the transfer chamber side. Front with sealant sandwiched around the entire periphery of the gate It comprises a gate valve capable sealable opening and closing the deposition chamber blocks the unloading gate, and a trap plate for trapping particles generated by the film-forming chamber is disposed on the unloading gate.

  According to the present invention, a semiconductor film having good in-plane uniformity can be stably realized for a long period of time by preventing the occurrence of internal leak in the film forming chamber due to particles generated in the film forming chamber. There is an effect.

FIG. 1 is a cross-sectional view schematically showing the structure of a plasma CVD apparatus which is a semiconductor film manufacturing apparatus according to Embodiment 1 of the present invention. FIG. 2 is a flowchart showing a process flow of the film forming process of the microcrystalline silicon film by the plasma CVD apparatus according to the first embodiment of the present invention. FIG. 3 is a diagram showing a cross-sectional structure when the substrate is carried into the film forming chamber and held on the substrate stage by the plasma CVD apparatus according to the first embodiment of the present invention. FIG. 4 is a diagram showing a cross-sectional structure during the formation of the microcrystalline silicon film by the plasma CVD apparatus according to the first embodiment of the present invention. FIG. 5 is a view showing a cross-sectional structure immediately after the microcrystalline silicon film forming process is completed in the plasma CVD apparatus according to the first embodiment of the present invention. FIG. 6 is a view showing a cross-sectional structure when the microcrystalline silicon film is formed by the plasma CVD apparatus according to the first embodiment of the present invention and the substrate is taken out of the film forming chamber. FIG. 7 shows the in-plane distribution of the number of deposited films and the thickness of the microcrystalline silicon film when the microcrystalline silicon film is continuously formed by the plasma CVD apparatus according to the first embodiment of the present invention and the conventional plasma CVD apparatus. It is a characteristic view which shows the relationship. FIG. 8 is a diagram showing an in-plane distribution of the film thickness of a microcrystalline silicon film manufactured by a conventional plasma CVD apparatus. FIG. 9 is a diagram showing an in-plane distribution of the film thickness of the microcrystalline silicon film manufactured by the plasma CVD apparatus according to the first embodiment of the present invention. FIG. 10 is a cross-sectional view schematically showing the structure of the plasma CVD apparatus according to the second embodiment of the present invention. FIG. 11 is a flowchart showing a process flow of the microcrystalline silicon film forming process by the plasma CVD apparatus according to the second embodiment of the present invention. FIG. 12 is a characteristic diagram showing the relationship between the number of deposited films and the in-plane distribution of the thickness of the microcrystalline silicon film when the microcrystalline silicon film is continuously formed by the plasma CVD apparatus according to the third embodiment of the present invention. It is. FIG. 13: is sectional drawing which shows typically the structure of the plasma CVD apparatus concerning Embodiment 3 of this invention.

  Embodiments of a semiconductor film manufacturing apparatus and a semiconductor film manufacturing method according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited to the following description, In the range which does not deviate from the summary of this invention, it can change suitably. In the drawings shown below, the scale of each member may be different from the actual scale for easy understanding.

Embodiment 1 FIG.
FIG. 1 is a cross-sectional view schematically showing the structure of a plasma CVD apparatus which is a semiconductor film manufacturing apparatus according to Embodiment 1 of the present invention. FIG. 1 shows a state in which a particle trap plate captures particles scattered in the deposition chamber when the microcrystalline silicon film is deposited by the plasma CVD apparatus according to the first embodiment. The plasma CVD apparatus according to the first embodiment can be used for forming an i-type microcrystalline silicon film (power generation layer) of a thin film solar battery cell (microcrystalline silicon cell). Hereinafter, a case where a microcrystalline silicon film is formed by the plasma CVD apparatus according to this embodiment will be described.

  As shown in FIG. 1, a substrate stage 1 that is a holding member that holds a translucent insulating substrate 2 that is a substrate to be processed (hereinafter referred to as a substrate 2) is installed inside the film forming chamber 5. . The substrate stage 1 is grounded. A substrate 2 is held on the substrate stage 1 so that the film forming surface is horizontal and upward.

In addition, a shower head 4 is provided on the upper surface of the film forming chamber 5 so as to face the substrate stage 1 and distribute and supply the source gas to the upper region of the substrate stage 1. The shower head 4 is connected to a raw material gas supply pipe 7 for feeding a raw material gas such as silane (SiH ₄ ) or hydrogen (H ₂ ) into the film forming chamber 5. The source gas supply pipe 7 is connected to a gas supply source such as a gas cylinder (not shown). The amount of source gas supplied into the film forming chamber 5 can be adjusted by a valve 7 a attached to the source gas supply pipe 7.

  The shower head 4 is connected to a cleaning gas supply pipe 26 for supplying a cleaning gas for cleaning the film forming chamber 5 to the film forming chamber 5. The cleaning gas supply pipe 26 is connected to a gas supply source such as a gas cylinder (not shown). The supply amount of the cleaning gas into the film forming chamber 5 can be adjusted by a valve 26 a attached to the cleaning gas supply pipe 26. The film forming chamber 5 is connected to an exhaust part (not shown) via an exhaust pipe 19, and the film forming chamber 5 can be evacuated by the exhaust part.

  The shower head 4 also serves as a high-frequency electrode for generating plasma of the source gas. The shower head 4 is connected to a power source 17 that applies high-frequency power to the shower head 4. By applying high frequency power from the power source 17 to the shower head 4, high frequency power is applied between the shower head 4 and the substrate stage 1, and plasma is generated between the substrate 2 and the shower head 4. The source gas dispersed from the shower head 4 is decomposed by plasma to produce a film-forming precursor, which is deposited on the substrate 2 and a microcrystalline silicon film 3 grows on the upper surface of the substrate 2.

  A transfer gate 15 that is a loading / unloading gate is provided on one side surface of the film forming chamber 5 as an opening for loading and unloading the substrate 2 into / from the film forming chamber 5. A gate valve 10 that can be freely opened and closed is disposed so as to cover the transfer gate 15. The gate valve 10 covers the transfer gate 15 through an O-ring 11 that is a sealing material disposed on the entire periphery of the peripheral edge of the transfer gate 15 on the side surface of the film forming chamber 5 and presses it against the side wall of the film forming chamber 5. As a result, the film forming chamber 5 is sealed.

  Further, in a region adjacent to the transfer gate 15, a transfer chamber 20 is provided which is connected to the film forming chamber 5 through the gate valve 10 and carries the substrate 2 into and out of the film forming chamber 5. Yes. The transfer chamber 20 can be depressurized to an arbitrary pressure by an exhaust means (not shown).

  After film formation, a microcrystalline silicon film 3 is formed on the substrate 2 placed on the substrate stage 1, and a large amount of residual film 6 is formed on the surfaces of the shower head 4 and the inner wall 5a of the film formation chamber. Is attached. Then, when the gas supply from the source gas supply pipe 7 is finished after the film formation is completed and the inside of the film formation chamber 5 is evacuated by the exhaust part via the exhaust pipe 19, the pressure in the film formation chamber 5 changes rapidly. Accordingly, a large amount of particles 8 are generated from the surface of the residue film 6 and scattered over a wide area in the film forming chamber 5.

  Therefore, in the plasma CVD apparatus according to the first embodiment, the particle trap plate 9 is provided at the position of the transfer gate 15 between the gate valve 10 disposed on one side surface of the film forming chamber 5 and the film forming chamber 5. Yes. With this particle trap plate 9, particles scattered from the film forming chamber 5 toward the gate valve 10 can be captured. Thereby, it is possible to prevent the particles 8 from adhering to the surface of the O-ring 11 disposed between the gate valve 10 and one side surface of the film forming chamber 5.

  Here, the vertical and horizontal dimensions of the particle trap plate 9 are set larger than the vertical and horizontal dimensions of the transfer gate 15 so that the particles 8 do not pass through the gap between the particle trap plate 9 and the transfer gate 15. . Further, the particle trap plate 9 has a sponge-like or mesh-like structure in which an infinite number of through-holes having a hole diameter of 0.2 μm or less are provided, so that a larger number of particles 8 can be trapped inside. It has a configuration.

  Next, details of a series of operations in the film forming process of the microcrystalline silicon film by the plasma CVD apparatus according to the first embodiment will be described with reference to FIGS. FIG. 2 is a flowchart showing a process flow of the film forming process of the microcrystalline silicon film by the plasma CVD apparatus according to the first embodiment. FIG. 3 is a diagram for explaining the inside of the film forming chamber 5 when the microcrystalline silicon film is formed by the plasma CVD apparatus according to the first embodiment. The substrate 2 is carried into the film forming chamber 5 and the substrate stage is moved. It is a figure which shows the cross-section at the time of hold | maintaining on 1. FIG. FIG. 4 is a diagram for explaining the inside of the film forming chamber 5 when the microcrystalline silicon film is formed by the plasma CVD apparatus according to the first embodiment, and is a cross section in the process of forming the microcrystalline silicon film. It is a figure which shows a structure. FIG. 5 is a diagram for explaining the inside of the film forming chamber 5 when the microcrystalline silicon film is formed by the plasma CVD apparatus according to the first embodiment, and is a cross section immediately after the film forming process of the microcrystalline silicon film is completed. It is a figure which shows a structure. FIG. 6 is a diagram for explaining the inside of the film forming chamber 5 when the microcrystalline silicon film is formed by the plasma CVD apparatus according to the first embodiment. It is a figure which shows the cross-sectional structure at the time of carrying out from the film forming chamber.

  When performing the film forming process of the microcrystalline silicon film, first, the gate valve 10 is opened (step S10), and the substrate 2 is introduced into the film forming chamber 5 from the transfer chamber 20 by the substrate transfer arm 12, and the substrate stage 1 is moved. Is held on (step S20, FIG. 3). During this time, the particle trap plate 9 is housed in the trap plate storage chamber 13 provided in the transfer gate 15 separately from the film forming chamber 5, so that the operation of transporting the substrate 2 is not hindered. That is, the particle trap plate 9 is provided with an extendable arm 14 as a drive mechanism of the particle trap plate 9, and the particle trap plate 9 is moved to the trap plate storage chamber 13 by driving the extendable arm 14. Is possible.

When the substrate 2 is introduced into the film forming chamber 5 and held on the substrate stage 1, the gate valve 10 is closed (step S30). Then, the telescopic arm 14 is extended, and the particle trap plate 9 stored in the trap plate storage chamber 13 is transported to a position where the transfer gate 15 between the gate valve 10 and the film forming chamber 5 is blocked (step S40). Thereafter, the film forming chamber 5 is evacuated through an exhaust pipe 19 by an exhaust unit (not shown), and the film forming chamber 5 is evacuated or decompressed. Next, a raw material gas 16 such as silane (SiH ₄ ) and hydrogen (H ₂ ) is sent into the film forming chamber 5 through the raw material gas supply pipe 7, and the raw material gas 16 is supplied to the substrate stage 1 through the shower head 4. Distributedly supplied to the upper region. The supply amount of the source gas 16 is adjusted by a valve 7 a attached to the source gas supply pipe 7.

  When a high frequency power is applied to the shower head 4 by the power source 17 in the state as described above to generate an electric field between the shower head 4 and the substrate stage 1, a plasma generation region, that is, the substrate 2 and the shower head 4 The source gas 16 is excited in a region facing each other to generate plasma 18, and the source gas 16 is decomposed by the plasma 18. Thereby, a film-forming precursor is generated, and this film-forming precursor is deposited on the substrate 2 to grow the microcrystalline silicon film 3 (step S50, FIG. 4).

  Here, the microcrystalline silicon film 3 adheres in large amounts to the inner wall 5a of the film forming chamber and the surface of the shower head 4. When these films are peeled off during film formation, they become particles 8 and fly to the vicinity of the transfer gate 15 on the flow of gas exhaust. However, in the plasma CVD apparatus according to the first embodiment, the particle trap plate 9 is provided at a position where the transfer gate 15 between the gate valve 10 and the film forming chamber 5 is closed, and all the particles 8 that have come here are here. It is captured and does not reach the gate valve 10.

  When the film forming process is completed and the supply of the raw material gas 16 is stopped, the film forming chamber 5 is sufficiently evacuated (step S60). Thereafter, the gate valve 10 is opened to carry the substrate 2 out to the transfer chamber 20 (step S70, FIG. 5). Due to the pressure difference between the film forming chamber 5 and the transfer chamber 20, the particles 8 are scattered in the film forming chamber 5 when the gate valve 10 is opened. In particular, when the transfer chamber 20 has a lower pressure than the film forming chamber 5, the scattered particles 8 are attracted toward the transfer gate 15. Again, in the plasma CVD apparatus according to the first embodiment, almost all the particles 8 are captured by the particle trap plate 9 and do not reach the vicinity of the gate valve 10.

  Thereafter, the telescopic arm 14 contracts and the particle trap plate 9 is stored in the trap plate storage chamber 13 (step S80, FIG. 6), and the substrate transfer arm 12 extends to carry the substrate 2 on the substrate stage 1 into the transfer chamber 20. (Step S90, FIG. 6). At this time, since the particle trap plate 9 is stored in the trap plate storage chamber 13, the particle trap plate 9 does not interfere with the substrate 2 or the substrate transfer arm 12 when the substrate 2 is carried out.

  Further, after the substrate 2 is unloaded from the film forming chamber 5 after the film formation is completed, the inside of the film forming chamber 5 can be cleaned while the particle trap plate 9 is stored in the trap plate storage chamber 13. When cleaning is performed, a cleaning gas is introduced into the film forming chamber 5 from the cleaning gas supply pipe 26 through the shower head 4. Then, high frequency power is applied from the power source 17 to the shower head 4 to generate cleaning gas plasma. All the particles 8 in the film forming chamber 5 react with the cleaning gas plasma and disappear.

  FIG. 7 shows the in-plane relationship between the number of deposited films and the thickness of the microcrystalline silicon film when 120 microcrystalline silicon films are continuously formed by the plasma CVD apparatus according to the first embodiment and the conventional plasma CVD apparatus. It is a characteristic view which shows the relationship with distribution. The in-plane distribution in the present embodiment is the maximum value (Max) and the minimum value (Min) of the film thickness in the plane, and it is a percentage by the calculation formula: [(Max−Min) / (Max + Min)] × 100. Defined in

  Here, a glass substrate having a vertical and horizontal dimension of 1.1 m × 1.4 m was used as a substrate, film formation was performed with a target film thickness of 1 μm, and film thicknesses at 100 locations within the substrate surface were measured by ellipsometry. In FIG. 7, the in-plane distribution value of the microcrystalline silicon film (Example 1) formed by the plasma CVD apparatus according to the first embodiment is indicated by Δ, and the microcrystalline silicon film formed by the conventional plasma CVD apparatus (comparison) The in-plane distribution values in Example) are indicated by black circles.

  From FIG. 7, in the film formation by the conventional plasma CVD apparatus (comparative example), the in-plane distribution value starts monotonically increasing from the 40th sheet onward and becomes ± 45% at the 120th sheet, and the in-plane distribution cannot be maintained. I understand that. On the other hand, in the film formation by the plasma CVD apparatus of the first embodiment (Example 1), the in-plane distribution value hardly changes from the start of film formation to the 80th sheet, and the in-plane distribution of ± 23% even at the 120th sheet. It can be seen that Although FIG. 7 shows the behavior of the in-plane distribution with respect to the film thickness, the same behavior is confirmed with respect to the in-plane distribution of the semiconductor film quality (crystal ratio, crystal orientation, amount of hydrogen in the film, etc.). .

  FIG. 8 is a diagram showing an in-plane distribution of the film thickness of a microcrystalline silicon film manufactured by a conventional plasma CVD apparatus. FIG. 9 is a diagram showing an in-plane distribution of the film thickness of the microcrystalline silicon film manufactured by the plasma CVD apparatus according to the first embodiment. 8 and 9 show the in-plane distribution of the film thickness of the microcrystalline silicon film produced in the 80th of 120 sheets shown in FIG. 7, respectively.

  As shown in FIG. 8, the microcrystalline silicon film produced by a conventional plasma CVD apparatus has an extremely thick film on the left side of the substrate, and the source gas flows in this direction during film formation. Conceivable. On the other hand, the microcrystalline silicon film manufactured by the plasma CVD apparatus according to the first embodiment does not show a large deviation in film thickness as shown in FIG. 9, and has a good in-plane distribution. I understand.

  As described above, the plasma CVD apparatus according to the first embodiment includes the particle trap plate 9 for capturing the particles 8 generated in the film forming chamber 5 between the gate valve 10 and the film forming chamber 5. . According to this configuration, particles 8 scattered in the film forming chamber 5 during film formation and during evacuation after completion of film formation can be captured, and scattering of the particles 8 to the outside of the film forming chamber 5 can be prevented. The scattered particles 8 can be prevented from adhering to the surface of the O-ring 11 of the gate valve 10. Thereby, the biting of the particles 8 into the gate valve 10 between the film forming chamber 5 and the transfer chamber 20 is suppressed, and the raw material gas 16 supplied into the film forming chamber 5 during the film formation is transferred to the transfer chamber 20. One-way flow in the direction is prevented, and the frequency of internal leakage in the gate valve 10 is reduced. For this reason, even if long-term continuous film formation is performed, a semiconductor film having good in-plane uniformity of film thickness and film quality can be stably formed.

  The size of the particle trap plate 9 is not particularly limited, and a semiconductor film can be uniformly formed on a large-scale glass substrate on a meter scale within the substrate surface. Further, since the particles 8 are prevented from adhering to the surface of the O-ring 11, the frequency of exchanging the O-ring 11 is reduced. Thereby, since the operating time of the plasma CVD apparatus can be made longer than before, productivity can be greatly improved.

Further, in the plasma CVD apparatus according to the first embodiment, the particle trap plate 9 includes the extendable arm 14 as a drive mechanism, and when the substrate 2 is transferred between the transfer chamber 20 and the film forming chamber 5, It is stored in a trap plate storage chamber 13 provided at a position where it does not interfere with substrate conveyance.
Thereby, when the substrate 2 is moved between the transfer chamber 20 and the film forming chamber 5, interference between the particle trap plate 9 and the substrate 2 can be prevented.

  Therefore, according to the first embodiment, the occurrence of internal leak in the film forming chamber 5 due to the particles 8 generated in the film forming chamber 5 is prevented, and the in-plane uniformity between the film thickness and the film quality is good. A semiconductor film can be realized stably for a long period of time.

  Further, when a thin film solar cell is manufactured by forming a microcrystalline silicon film with the plasma CVD apparatus according to the first embodiment, a large area glass substrate (1.1 × 1.4) generally used in mass production of thin film solar cells. It is expected that good power generation efficiency can be realized with a good in-plane distribution.

Embodiment 2. FIG.
FIG. 10 is a cross-sectional view schematically showing the structure of the plasma CVD apparatus according to the second embodiment. FIG. 10 shows a state in which the inside of the film forming chamber 5 and the particle trap plate 9 are cleaned at the end of the formation of the microcrystalline silicon film by the plasma CVD apparatus according to the first embodiment. The plasma CVD apparatus according to the second embodiment basically has the same configuration as that of the plasma CVD apparatus according to the first embodiment. Here, as shown in the first embodiment, during film formation and after film formation ends. The particles 8 scattered in the film forming chamber 5 are almost completely captured by the particle trap plate 9.

  The plasma CVD apparatus according to the second embodiment is provided with a shower head 21, a cleaning gas supply pipe 22, and a power source 23 with respect to the trap plate storage chamber 13. The cleaning gas plasma 24 can be generated in the plate storage chamber 13. All the particles 8 captured by the particle trap plate 9 react with the cleaning gas plasma 24 and disappear. Thereby, the particle trap plate 9 can be cleaned.

  The cleaning of the particle trap plate 9 is performed simultaneously with the cleaning process in the film forming chamber 5, so that the cleaning gas 25 supplied to the trap plate storage chamber 13 is exhausted outside the apparatus through the film forming chamber 5. Is done. As described above, in the plasma CVD apparatus according to the second embodiment, the particle trap plate 9 can be cleaned every film formation, and the trapped particles 8 are detached from the particle trap plate 9 and the gate valve 10 Adhesion to the surface of the O-ring 11 is suppressed.

  Next, a series of operations in the process of forming a microcrystalline silicon film by the plasma CVD apparatus according to the second embodiment will be described with reference to FIG. FIG. 11 is a flowchart illustrating a process flow of a microcrystalline silicon film forming process performed by the plasma CVD apparatus according to the second embodiment. In the process flow of FIG. 11, items regarding cleaning are added to the process flow of the plasma CVD apparatus according to the first embodiment shown in FIG. Here, description of step 10 to step 90 is omitted.

  After the film formation is completed, the substrate 2 is unloaded from the film formation chamber 5 and then the particle trap plate 9 is stored in the trap plate storage chamber 13. The cleaning gas 25 is introduced through the cleaning gas 27, and the cleaning gas 27 is introduced into the film forming chamber 5 from the cleaning gas supply pipe 26 through the shower head 4 (step S100). Then, in the trap plate storage chamber 13, high frequency power is applied from the power source 23 to the shower head 21, and cleaning gas plasma 24 is generated (step S110). All particles 8 captured by the particle trap plate 9 react with the cleaning gas plasma and disappear. In the film forming chamber 5, high frequency power is applied from the power source 17 to the shower head 4 to generate a cleaning gas plasma 28 (step S110). All the particles 8 in the film forming chamber 5 react with the cleaning gas plasma and disappear.

  FIG. 12 is a characteristic showing the relationship between the number of deposited microcrystalline silicon films and the in-plane distribution of the thickness of the microcrystalline silicon film when 120 microcrystalline silicon films are continuously formed by the plasma CVD apparatus according to the third embodiment. FIG. As in the case of FIG. 7, the in-plane distribution is the maximum value (Max) and the minimum value (Min) of the film thickness in the plane, and the calculation formula: [(Max−Min) / (Max + Min)] × 100 is defined as a percentage. In addition, FIG. 12 also shows in-plane distribution values of the microcrystalline silicon film formed continuously by the plasma CVD apparatus according to the first embodiment and the conventional plasma CVD apparatus.

  Here, similarly to the case of FIG. 7, a glass substrate having a vertical and horizontal dimension of 1.1 m × 1.4 m is used as a substrate, film formation is performed with a target film thickness of 1 μm, and film thicknesses at 100 locations in the substrate surface are set. Measured by ellipsometry. In FIG. 12, the in-plane distribution value of the microcrystalline silicon film (Example 1) formed by the plasma CVD apparatus according to the first embodiment is indicated by Δ, and the fine film formed by the plasma CVD apparatus according to the second embodiment is shown. The in-plane distribution of the film thickness of the crystalline silicon film (Example 2) is indicated by black square marks, and the in-plane distribution value of the microcrystalline silicon film (comparative example) formed by the conventional plasma CVD apparatus is indicated by black circle marks. Yes.

  From FIG. 12, in the film formation by the conventional plasma CVD apparatus (comparative example), the in-plane distribution value starts monotonically increasing from the 40th sheet onward, and becomes ± 45% at the 120th sheet, and the in-plane distribution cannot be maintained. I understand that. On the other hand, in the film formation by the plasma CVD apparatus of the second embodiment (Example 2), the in-plane distribution value hardly increases between the start of film formation and the 120th sheet, and is substantially constant at ± 13-16%. I understand that This is lower than the film thickness in-plane distribution value when continuous film formation is performed by the conventional plasma CVD apparatus and the plasma CVD apparatus of the first embodiment, and a better in-plane distribution value has a larger continuous production value. It shows that it is obtained for membrane treatment. That is, by using the plasma CVD apparatus of the second embodiment, the work frequency of exchanging the O-ring 11 of the gate valve 10 in the transfer gate 15 is greatly reduced. Thereby, since the operating time of the plasma CVD apparatus can be made longer than before, productivity can be greatly improved.

  In FIG. 12, the behavior of the in-plane distribution with respect to the film thickness is shown as an example. However, the same behavior is confirmed for the in-plane distribution of the semiconductor film quality (crystallization rate, crystal orientation, amount of hydrogen in the film, etc.). ing.

  As described above, the plasma CVD apparatus according to the second embodiment includes the particle trap plate 9 for capturing the particles 8 generated in the film forming chamber 5 between the gate valve 10 and the film forming chamber 5. . According to this configuration, particles 8 scattered in the film forming chamber 5 during film formation and during evacuation after completion of film formation can be captured, and scattering of the particles 8 to the outside of the film forming chamber 5 can be prevented. The scattered particles 8 can be prevented from adhering to the surface of the O-ring 11 of the gate valve 10. Thereby, the biting of the particles 8 into the gate valve 10 between the film forming chamber 5 and the transfer chamber 20 is suppressed, and the raw material gas 16 supplied into the film forming chamber 5 during the film formation is transferred to the transfer chamber 20. One-way flow in the direction is prevented, and the frequency of internal leakage in the gate valve 10 is reduced. For this reason, even if long-term continuous film formation is performed, a semiconductor film having good in-plane uniformity of film thickness and film quality can be stably formed. The size of the particle trap plate 9 is not particularly limited, and a semiconductor film can be uniformly formed on a large-scale glass substrate on a meter scale within the substrate surface.

  Further, since the plasma CVD apparatus according to the second embodiment can generate the cleaning gas plasma in the trap plate storage chamber 13 separately from the film forming chamber 5, the particle trap plate 9 is periodically cleaned. And the captured particles 8 can be periodically lost. Thereby, it is possible to prevent the once captured particles 8 from being detached from the particle trap plate 9 and re-scattering into the film forming chamber 5.

  Then, the particle trap plate 9 is always in a clean state, and a high particle capture rate can be maintained, and the particle 8 can be prevented from biting into the gate valve 10 and the occurrence of internal leak can be suppressed. As a result, even if long-term continuous film formation is performed, it is possible to stably realize a good film thickness and in-plane uniformity of film quality. In addition, the maintenance cycle of the gate valve 10 can be prolonged, and the downtime of the plasma CVD apparatus is reduced, thereby improving productivity.

  Therefore, according to the second embodiment, the occurrence of internal leakage in the film forming chamber 5 due to the particles 8 generated in the film forming chamber 5 is prevented, and the in-plane uniformity of the film thickness and the film quality is good. A semiconductor film can be realized stably for a long period of time.

  Further, when a thin film solar cell is manufactured by forming a microcrystalline silicon film with the plasma CVD apparatus according to the second embodiment, a large area glass substrate (1.1 × 1.4) generally used in mass production of thin film solar cells. It is expected that good power generation efficiency can be realized with a good in-plane distribution.

Embodiment 3 FIG.
FIG. 13 is a sectional view schematically showing the structure of the plasma CVD apparatus according to the third embodiment. FIG. 13 shows a state in which the inside of the film forming chamber 5 and the particle trap plate 9 are cleaned at the end of film formation of the microcrystalline silicon film by the plasma CVD apparatus according to the first embodiment. The plasma CVD apparatus according to the third embodiment basically has the same configuration as the plasma CVD apparatus according to the first embodiment. Here, as shown in the first embodiment, during film formation and after film formation is completed. The particles 8 scattered in the film forming chamber 5 are almost completely captured by the particle trap plate 9.

  In the plasma CVD apparatus according to the third embodiment, a cleaning gas radical source 28 is connected to the trap plate storage chamber 13, and the particle trap plate 9 does not generate plasma in the trap plate storage chamber 13. Can be cleaned. That is, the cleaning gas radical 29 supplied from the cleaning gas radical source 28 is diffused into the trap plate storage chamber 13 through the shower head 21, reacts with the particles 8 captured by the particle trap plate 9 and disappears.

  The cleaning of the particle trap plate 9 is performed simultaneously with the cleaning process in the film forming chamber 5, so that the cleaning gas radical 29 supplied to the trap plate storage chamber 13 is removed from the apparatus through the film forming chamber 5. Exhausted. As described above, in the plasma CVD apparatus according to the third embodiment, the particle trap plate 9 can be cleaned for each film formation, and the trapped particles 8 are detached from the particle trap plate 9 and the gate valve 10 Adhesion to the surface of the O-ring 11 is suppressed.

  A series of operations in the film forming process of the microcrystalline silicon film by the plasma CVD apparatus according to the third embodiment is basically the same as the process of forming the microcrystalline silicon film by the plasma CVD apparatus according to the second embodiment. is there. The process of forming the microcrystalline silicon film by the plasma CVD apparatus according to the third embodiment is different from the process of forming the microcrystalline silicon film by the plasma CVD apparatus according to the second embodiment. In S100 and S110, instead of the cleaning gas 25, the cleaning gas radical 29 is introduced from the cleaning gas radical source 28 into the trap plate storage chamber 13 through the shower head 21. The cleaning gas radical 29 reacts with the particles 8 captured by the particle trap plate 9 and disappears, whereby the particle trap plate 9 can be cleaned.

  As described above, the plasma CVD apparatus according to the third embodiment includes the particle trap plate 9 for capturing the particles 8 generated in the film forming chamber 5 between the gate valve 10 and the film forming chamber 5. . According to this configuration, particles 8 scattered in the film forming chamber 5 during film formation and during evacuation after completion of film formation can be captured, and scattering of the particles 8 to the outside of the film forming chamber 5 can be prevented. The scattered particles 8 can be prevented from adhering to the surface of the O-ring 11 of the gate valve 10. Thereby, the biting of the particles 8 into the gate valve 10 between the film forming chamber 5 and the transfer chamber 20 is suppressed, and the raw material gas 16 supplied into the film forming chamber 5 during the film formation is transferred to the transfer chamber 20. One-way flow in the direction is prevented, and the frequency of internal leakage in the gate valve 10 is reduced. For this reason, even if long-term continuous film formation is performed, a semiconductor film having good in-plane uniformity of film thickness and film quality can be stably formed. The size of the particle trap plate 9 is not particularly limited, and a semiconductor film can be uniformly formed on a large-scale glass substrate on a meter scale within the substrate surface.

  Further, since the plasma CVD apparatus according to the third embodiment can directly supply the cleaning gas radical 29 to the trap plate storage chamber 13, the particle trap plate 9 can be periodically cleaned and captured. Particles 8 can be periodically lost. Thereby, it is possible to prevent the once captured particles 8 from being detached from the particle trap plate 9 and re-scattering into the film forming chamber 5.

  Then, the particle trap plate 9 is always in a clean state, and a high particle capture rate can be maintained, and the particle 8 can be prevented from biting into the gate valve 10 and the occurrence of internal leak can be suppressed. As a result, even if long-term continuous film formation is performed, it is possible to stably realize a good film thickness and in-plane uniformity of film quality. In addition, the maintenance cycle of the gate valve 10 can be prolonged, and the downtime of the plasma CVD apparatus is reduced, thereby improving productivity.

  Therefore, according to the third embodiment, the occurrence of internal leak in the film forming chamber 5 due to the particles 8 generated in the film forming chamber 5 is prevented, and the in-plane uniformity of the film thickness and the film quality is good. A semiconductor film can be realized stably for a long period of time.

  Further, when a thin film solar cell is manufactured by forming a microcrystalline silicon film with the plasma CVD apparatus according to the third embodiment, a large-area glass substrate (1.1 × 1.4) generally used in mass production of thin film solar cells. It is expected that good power generation efficiency can be realized with a good in-plane distribution.

  As described above, the semiconductor film manufacturing apparatus according to the present invention is useful for stably realizing good in-plane uniformity for a long period of time, and in particular, the photoelectric conversion layer (semiconductor layer) of a thin film solar cell. Suitable for manufacturing.

1 Substrate stage 2 Translucent insulating substrate (substrate)
3 Microcrystalline silicon film 4 Shower head 5 Film forming chamber 5a Inner wall of film forming chamber 6 Residual film 7 Source gas supply pipe 7a Valve 8 Particle 9 Particle trap plate 10 Gate valve 11 O-ring 12 Substrate transport arm 13 Trap plate storage chamber 14 Telescopic arm 15 Transfer gate 16 Raw material gas 17 Power source 18 Plasma 19 Exhaust pipe 20 Transfer chamber 21 Shower head 22 Cleaning gas supply pipe 23 Power source 24 Cleaning gas plasma 25 Cleaning gas 26 Cleaning gas supply pipe 26a Valve 27 Cleaning gas 28 Cleaning gas radical source 29 Cleaning gas radical

Claims (11)

The substrate to be processed is held so that the film formation surface is horizontal and upward, and the source gas plasma is generated in a state where the material gas is supplied from the upper part of the film formation surface toward the film formation surface. A film forming chamber in which the raw material gas is decomposed by the plasma and deposited on the film forming surface, and a thin film can be formed;
A loading / unloading gate for loading and unloading the substrate to be processed into the deposition chamber provided on one side wall of the deposition chamber;
A depressurized transfer chamber connected to the film forming chamber via the load / unload gate for loading and unloading the substrate to be processed into the film forming chamber;
An openable / closable gate valve capable of sealing the film forming chamber by closing the carry-in / out gate with a sealant sandwiched around the entire periphery of the peripheral portion of the carry-in / out gate on the side surface of the one side wall portion on the transfer chamber side. When,
A trap plate for capturing particles generated in the film forming chamber disposed at the carry-in / out gate;
A semiconductor film manufacturing apparatus comprising: A trap plate moving means for moving the trap plate to a position that does not interfere with the substrate transport when the substrate to be processed is carried into or out of the film forming chamber;
The semiconductor film manufacturing apparatus according to claim 1. A trap plate storage chamber provided on the one side wall portion for storing the trap plate;
The semiconductor film manufacturing apparatus according to claim 2. Moving and storing the trap plate into the trap plate storage chamber when the substrate is carried into the film forming chamber from the transfer chamber and when being transferred from the film forming chamber to the transfer chamber;
The semiconductor film manufacturing apparatus according to claim 3. Cleaning gas introduction means for introducing cleaning gas into the trap plate storage chamber, and plasma generation means for generating plasma of the cleaning gas in the trap plate storage chamber,
The semiconductor film manufacturing apparatus according to claim 3 or 4, wherein A cleaning gas radical introducing means for introducing cleaning gas radicals into the trap plate storage chamber;
The semiconductor film manufacturing apparatus according to claim 3 or 4, wherein A semiconductor film manufacturing method for forming a semiconductor film on a substrate to be processed held in a film forming chamber capable of being evacuated by a plasma CVD method,
A first step of carrying the substrate to be processed into a film forming chamber from a loading / unloading gate provided on one side wall of the film forming chamber;
The loading / unloading gate is closed from the outside of the film forming chamber with a gate valve in a state where a sealant is sandwiched around the entire periphery of the peripheral edge of the loading / unloading gate on the outer side surface of the film forming chamber on the one side wall portion. A second step of
A third step of arranging a trap plate for capturing particles generated in the film forming chamber at the loading / unloading gate;
A fourth step of forming a semiconductor film on a substrate to be processed by a CVD method in the film forming chamber;
A method for manufacturing a semiconductor film, comprising: After the fourth step,
A fifth step of evacuating the deposition chamber after deposition of the semiconductor film;
A sixth step of opening the gate valve;
The method of manufacturing a semiconductor film according to claim 7, comprising: After the sixth step,
A seventh step of moving the trap plate to a trap plate storage chamber that is provided on the one side wall portion and stores the trap plate;
An eighth step of carrying out the substrate to be processed from the film forming chamber;
The method of manufacturing a semiconductor film according to claim 8, comprising: After the eighth step,
A cleaning gas is flowed into the film forming chamber to clean the film forming chamber, and a cleaning gas plasma is generated in the trap plate storage chamber, so that the trap plate is attached to the trap plate by exposing it to the plasma. Having a ninth step of removing the particles;
The method of manufacturing a semiconductor film according to claim 9. After the eighth step,
A cleaning gas is flowed into the film forming chamber to clean the film forming chamber, and radicals of the cleaning gas are introduced into the trap plate storage chamber so that the trap plate is attached to the trap plate by exposing the trap plate to the radicals. Having a tenth step of removing the particles;
The method of manufacturing a semiconductor film according to claim 9.

Images