JP2012216718A - Cleaning method of cvd apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning method of a CVD apparatus capable of reducing the usage of reaction gas.SOLUTION: Cleaning of a film deposition chamber 22 is carried out by performing a non-plasma step and a plasma step. In the non-plasma step, a mixture gas of fluorine and nitrogen, or the like, is introduced into the film deposition chamber 22 and the interior of which is maintained lower than 250°C. In the non-plasma step, plasma discharge is not performed. In the plasma step, pressure in the film deposition chamber 22 is reduced, and then a mixture gas of fluorine gas and nitrogen gas, or the like, is introduced and plasma is generated. Interior of the film deposition chamber 22 is also maintained lower than 250°C in the plasma step.

Description

  The present invention relates to a method for cleaning the inside of a film forming chamber of a CVD apparatus. More specifically, the present invention is applied to a CVD apparatus equipped with a high frequency power supply capable of plasma discharge, and can form a film on a substrate in the film forming chamber. The present invention relates to a method for cleaning a film formation chamber of a CVD apparatus.

  A solar power generation element used for a solar power generation device (photoelectric conversion device) is obtained by laminating a plurality of thin film layers such as a transparent conductive film, an amorphous silicon thin film, and a microcrystalline silicon thin film on a glass substrate. These thin film layers are generally formed by using a CVD (Chemical Vapor Deposition) apparatus to fill a reaction gas into a film forming chamber into which a glass substrate is inserted and to cause a chemical reaction. Therefore, in a CVD apparatus used for mass production or the like, unnecessary compounds or precipitates are stuck in the film forming chamber. These compounds, precipitates, and the like cause contamination and degrade the characteristics of the photovoltaic power generation element. Therefore, it is necessary to periodically clean the film formation chamber.

  Patent Document 1 discloses a method for cleaning a semiconductor device. In the semiconductor device cleaning method described in Patent Document 1, a mixed gas is introduced into a chamber (a film formation chamber) included in the semiconductor device to etch unnecessary materials in the film formation chamber. In Patent Document 1, various methods are described as examples of the cleaning method.

JP 2009-533853 A

  According to the measure of Patent Document 1, there is a complaint that the film forming chamber cannot be cleaned to every corner, and a residue remains in the details of the film forming chamber. That is, since the measure of Patent Document 1 activates the mixed gas using plasma discharge, the region where plasma is generated has a high cleaning effect. However, the region where plasma exists in the film formation chamber is limited, and the plasma does not reach the corner of the film formation chamber, and the residue remains without being removed.

  Further, in the measure of Patent Document 1, after argon gas is injected into the chamber and plasma discharge is started, the mixed gas is introduced into the chamber, the precipitate and the mixed gas are reacted, and the generated gaseous reaction is performed. The product is evacuated to remove precipitates from the chamber. However, in the cleaning method described in Patent Document 1, since a mixed gas is introduced into the chamber and evacuation is continued during the cleaning process, a large amount of mixed gas is required. In addition, it is necessary to discharge plasma in the chamber and maintain a vacuum, and a large amount of power is consumed by long-time cleaning. That is, in the cleaning method described in Patent Document 1, there is a risk that the cost for removing the deposit is increased.

  In view of the above-described present situation, an object of the present invention is to provide a CVD apparatus cleaning method capable of cleaning a film forming chamber to every corner and contributing to a reduction in reaction gas consumption.

  The invention described in claim 1 for solving the above-described problem has a film forming chamber provided with a high frequency power supply device capable of plasma discharge, a film forming chamber side decompression device, and a reactive gas injection device, and A CVD apparatus cleaning method capable of forming a film on a substrate in a film chamber includes a non-plasma process and a plasma process, wherein the non-plasma process is performed by injecting a first reaction gas into the film formation chamber for a predetermined time. Or a step of evacuating the film formation chamber while injecting the first reaction gas into the film formation chamber, and the plasma step is to evacuate the film formation chamber while injecting the second reaction gas into the film formation chamber. And a plasma discharge process, wherein the first reaction gas and the second reaction gas contain a fluorine element.

A high-frequency power supply device capable of plasma discharge, a film formation chamber-side decompression device, and a film formation chamber provided with a reactive gas injection device refer to a film formation chamber provided with an apparatus capable of film formation.
The CVD apparatus cleaning method employed in the present invention includes a non-plasma process and a plasma process in a CVD apparatus having a film formation chamber capable of film formation.

  The non-plasma step is a step of injecting a first reaction gas into the film formation chamber and allowing a predetermined time to elapse, or a step of exhausting the film formation chamber while injecting the first reaction gas into the film formation chamber. The process is a process of exhausting the film formation chamber while injecting the second reaction gas into the film formation chamber and performing plasma discharge. In other words, the non-plasma process is a cleaning process using only a chemical reaction without performing plasma discharge. Implement a flow system that exhausts while injecting into the tank.

  On the other hand, the plasma process is a process for exhausting the film formation chamber while injecting the second reaction gas into the film formation chamber and performing plasma discharge. In other words, the plasma process is a cleaning process by a chemical reaction in a plasma atmosphere, and a flow method is performed in which the second reaction gas is exhausted while being injected into the film formation chamber.

The composition of the first reaction gas and the second reaction gas may be the same.
In the non-plasma process, there are a non-flow method and a flow method as a method for supplying the first reaction gas.
In the non-plasma process, the region where the first reactive gas reaches can be cleaned, and the film formation chamber can be cleaned to every corner. On the other hand, in the non-plasma process, since the residue reacts with the reactive gas without depending on the plasma, it takes time to remove the residue as compared with the case of using plasma together. Therefore, for example, when only the non-plasma process is performed, the residue may not be sufficiently removed in a short time in a region where the residue is thickly stacked.

On the other hand, in the plasma process, since the reaction gas is activated by using plasma together, the effect of removing the residue is high. Therefore, the residue in the film forming chamber can be removed quickly and reliably. Therefore, even if the deposit is thick, it can be sufficiently removed. In addition, the portion where the deposit accumulates is often in the vicinity of the region where the substrate is installed or in the vicinity of the region where the film forming gas is introduced into the film forming chamber. It is. For this reason, after the plasma process, satisfactory residue removal can be performed even for the portion where the deposits are thickened.
That is, the present invention can remove thin precipitates that are spread over a wide range in a non-plasma process, and can remove residues that have been deposited thickly in the plasma process.
In particular, in a film forming apparatus for forming a substrate having a plurality of layers having different crystal structures, such as a solar cell called a hybrid type, in one film forming chamber, precipitates having different hardness, composition, and reactivity are generated. It overlaps and adheres. When cleaning such a film formation chamber, it is effective to change the reaction conditions for cleaning, and the effect of using the plasma process and the non-plasma process as in the present invention is high.
Furthermore, the plasma as in the present invention is also used for cleaning a film forming chamber in which a precipitate having a covalent bond such as a silicon oxide film (particularly an n-type silicon oxide film) or a film forming chamber in which an alloy is deposited. The effect of combining the process and the non-plasma process is high.
Further, according to the present invention, it contributes to saving of the reaction gas. That is, in the non-plasma process, when the first reaction gas is supplied by the non-flow method, the amount of gas used is small. Also in the plasma process, since the finishing process can be performed quickly, the amount of gas used is small. That is, by combining the non-plasma process and the plasma process, the amount of gas used for removing the residue can be reduced as a result. Also, the total time required for cleaning can be shortened.
That is, according to the present invention, the synergistic effect by combining the non-plasma process and the plasma process allows the film forming chamber to be more thoroughly cleaned, reduces the consumption of the reaction gas, and further shortens the required time. it can.

  According to a second aspect of the present invention, in the non-plasma process and / or the plasma process, the temperature in the film forming chamber is adjusted to a temperature of less than 250 degrees Celsius. This is a cleaning method.

In the non-plasma process, it is desirable to raise the temperature in the deposition chamber in order to increase the reactivity of the reaction gas. From the viewpoint of improving the cleaning efficiency, it can be said that the higher the temperature of the film forming chamber, the better.
However, according to experiments by the present inventors, it has been found that if the temperature in the film forming chamber is raised above a certain level, the film forming chamber and the members of the flow paths communicating therewith are corroded.
That is, stainless steel is frequently used in the film forming chamber and the flow path communicating therewith in order to prevent corrosion. Stainless steel is hard to rust, but it corrodes when it comes into contact with reactive gases containing fluorine. The corrosion rate increases as the environmental temperature increases, but according to the experiments by the present inventors, the corrosion rate rapidly increases at about 250 degrees Celsius.
In the present invention, as described above, in the non-plasma process, the reaction rate is accelerated if the temperature in the film forming chamber is raised excessively in order to increase the reactivity of the first reaction gas, and the film forming chamber is corroded by excessive cleaning. May be.
In the CVD apparatus cleaning method employed in the present invention, the temperature in the film forming chamber is set to less than 250 degrees Celsius. That is, even if stainless steel is used for the film formation chamber or the like, the film formation chamber or the like can be prevented from being corroded.
The same applies to the plasma process. By adjusting the temperature in the deposition chamber to a temperature of less than 250 degrees Celsius, the deposition chamber is prevented from being corroded even if stainless steel is used in the deposition chamber. it can.

  The invention according to claim 3 is characterized in that the first reaction gas is any one of fluorine gas, a mixed gas containing at least fluorine gas and nitrogen gas, and chlorine trifluoride gas. 2. A cleaning method for a CVD apparatus according to 2.

  Since fluorine gas and chlorine trifluoride gas are excellent in reactivity, they are suitable for a non-plasma process using only a chemical reaction. In addition, fluorine gas and chlorine trifluoride gas are suitable as cleaning gases because of their extremely low global warming potential (GWP).

  The invention according to claim 4 is characterized in that the second reaction gas is fluorine gas, a mixed gas containing at least fluorine gas and nitrogen gas, a carbonyl fluoride gas, a mixed gas containing at least carbonyl fluoride gas and oxygen gas, The CVD apparatus cleaning method according to any one of claims 1 to 3, wherein the gas is chlorine trifluoride gas.

  Since the carbonyl fluoride gas is excellent in reactivity like the above-described fluorine gas and chlorine trifluoride gas, it is suitable for a plasma process in which a fast reaction is desired. Carbonyl fluoride gas is also suitable as a cleaning gas because it has a very low global warming potential (GWP).

  In the non-plasma process, when a mixed gas of fluorine gas and nitrogen gas is used, the partial pressure of the fluorine gas in the deposition chamber is preferably 1000 to 5000 Pascals (Claim 5).

  In the non-plasma process, it is desirable that chlorine trifluoride gas is used and the partial pressure of chlorine trifluoride gas in the film forming chamber is 1000 to 5000 Pascals.

  In the plasma step, it is preferable that the partial pressure of the fluorine gas in the film forming chamber when a mixed gas of fluorine gas and nitrogen gas is used is 20 to 1000 Pascal.

  Note that the total pressure in the film formation chamber under these conditions is recommended to be 100 to 1000 Pascals.

  In the plasma step, it is preferable that the partial pressure of the carbonyl fluoride gas in the deposition chamber when using a mixed gas of carbonyl fluoride gas and oxygen gas is 20 to 1000 Pascal.

  Note that the total pressure in the film formation chamber under these conditions is recommended to be 100 to 1000 Pascals.

  Furthermore, in the plasma step, it is preferable that the partial pressure in the film forming chamber when using chlorine trifluoride gas is 20 to 1000 Pascal.

  It is recommended that the total pressure in the film forming chamber under this condition is 20 to 1000 Pascal.

  The invention according to claim 10 is the CVD apparatus cleaning method according to any one of claims 1 to 9, wherein the plasma process is performed again after the non-plasma process and the plasma process are sequentially performed. is there.

  In the CVD apparatus cleaning method employed in the present invention, the non-plasma process and the plasma process are sequentially performed, and then the plasma process is performed again. That is, finally, a plasma process is performed to finish cleaning. As described above, the film formation chamber can be finished by removing most of unnecessary substances in the non-plasma process and removing the deposits thickly stacked in the plasma process.

  The invention described in claim 11 has a gas analyzer, and the reaction gas discharged from the film forming chamber is monitored by the gas analyzer. This is a method for cleaning a CVD apparatus.

  In the CVD apparatus cleaning method employed in the present invention, the reaction gas discharged from the film forming chamber is monitored by a gas analyzer. For example, in the plasma process, it is difficult to check the cleaning status in the film forming chamber. That is, the cleaning state in the film forming chamber can be grasped by analyzing the components of the reaction gas with the gas analyzer. As a result, the film formation chamber can be prevented from being corroded by excessive cleaning.

  In addition, it is desirable to introduce a film material into the film formation chamber and generate plasma after performing the cleaning method.

  According to this method, a thin film is formed on the film forming chamber itself or a device such as a heater in the film forming chamber. The coating functions as a protective film for equipment and the like.

  According to a twelfth aspect of the present invention, the film formation chamber includes a transfer chamber capable of carrying in and out the substrate, the transfer chamber includes a storage chamber, and the storage chamber is coupled to the film formation chamber. 12. The CVD apparatus cleaning method according to claim 1, wherein the non-plasma process is performed in a state where the chamber can be integrated and the storage chamber and the film formation chamber are integrated. is there.

The transfer chamber is for carrying the substrate into and out of the film formation chamber. That is, the transfer chamber does not include an apparatus capable of forming a film in the storage chamber. For this reason, it is difficult to inject the reaction gas into the storage chamber, and cleaning of the storage chamber has been performed manually.
In the CVD apparatus cleaning method employed in the present invention, the non-plasma process is performed in a state in which the storage chamber of the transfer chamber and the film formation chamber are integrated. That is, when the film forming chamber is cleaned, the storage chamber can also be cleaned.

  According to the cleaning method for a CVD apparatus of the present invention, by combining the non-plasma process and the plasma process, the film forming chamber can be cleaned to every corner, and the consumption of the reaction gas can be reduced.

It is the whole perspective view which looked at the CVD apparatus used for the cleaning method of the CVD apparatus of this invention from the movement chamber side. It is the perspective view which looked at the chamber for movement from the storage room entrance / exit side. It is a perspective view which shows the internal structure of the film-forming chamber. It is a perspective view of the electrode built in the film-forming chamber. It is a perspective view which shows the inside of the chamber for a movement. It is a plane sectional view showing the internal structure of a chamber body. It is a perspective view of a base carrier used in an embodiment of the present invention. It is a disassembled perspective view of the base | substrate carrier of FIG. It is an external appearance perspective view which shows the state which the chamber for movement and the film-forming chamber joined. It is a partially broken perspective view of a transfer chamber and a film formation chamber showing a state in which a substrate carrier moves from the transfer chamber to the film formation chamber. It is a perspective view which shows the film-forming chamber in which the gas analyzer was provided between the valve and the vacuum pump.

  Hereinafter, embodiments of a cleaning method for a CVD apparatus according to the present invention will be described in detail with reference to the drawings. In addition, the following description is for facilitating the understanding of the embodiment, and the present invention should not be understood to be limited thereby.

  In FIG. 1, reference numeral 1 denotes a CVD apparatus used for a CVD apparatus cleaning method according to an embodiment of the present invention. The CVD apparatus 1 forms a semiconductor layer on a glass base 46 (substrate). The CVD apparatus 1 is roughly composed of a substrate receiving / dispensing apparatus 2, a film forming chamber group 3, a moving chamber 5 and a chamber moving apparatus 32.

To explain sequentially, the substrate receiving / dispensing device 2 is such that five substrate moving devices 8 are provided on the base member 4 as shown in FIG.
The film forming chambers 15 constituting the film forming chamber group 3 all have the same structure. FIG. 3 is a perspective view showing the internal structure of the film forming chamber 15.

  As shown in FIGS. 1 and 3, the outer shape of the film forming chamber 15 is a box shape in which the top surface, the bottom surface, the left and right side surfaces, and the back surface are surrounded. A rectangular film forming chamber entrance 16 is provided on the front surface. It has been. A flange 17 is provided at the opening end of the film forming chamber entrance 16.

An airtight shutter 18 is provided at the film forming chamber entrance 16.
The shutter 18 employs what is called a slide-type gate valve, and the door-like member 14 slides in the direction of the arrow as shown by the arrow in FIG.

  Inside the film forming chamber 15 is a film forming chamber 22 for forming a film on the substrate 46 by plasma CVD. In addition, as shown in FIG. 5, six heaters 23a, b, c, d, e, and f and five electrodes 25a, b, c, d, and e are provided. That is, the heater 23 is illustrated as a thin rectangle in FIG. 5, and the electrode 25 is illustrated as a thick rectangle.

  The heaters 23a, b, c, d, e, and f are all plate-like surface heaters, but their internal structure is the same as that used in known plasma CVD, for example, inside the plate body. It is possible to employ one in which a sheathed heater is embedded, a plate-like ceramic heater, or a halogen lamp arranged in a planar shape.

  Of the six heaters 23a, b, c, d, e, and f, the heaters 23a and 23f at both ends are attached to the inner walls 24a and 24b on the side surfaces of the film forming chamber 22. The other heaters 23b, c, d are placed vertically in parallel in the film forming chamber 22 with a predetermined interval.

  On the other hand, as shown in FIG. 4, the electrodes 25a, b, c, d, and e have shower plates 27 attached to both surfaces of the frame body 26.

  A gas pipe 31 is connected to the frame body 26 and is connected to a source gas supply source 61 (reactive gas injection device). The frame body 26 is connected to a high frequency AC power source 60 (high frequency AC power source) via a matching circuit (MBX).

As shown in FIG. 3, the electrodes 25a, b, c, d, e are vertically placed in parallel between the six heaters 23a, b, c, d, e, f.
Further, a substrate moving device 29 similar to the substrate receiving / dispensing device 2 described above is provided inside the film forming chamber 22. The number of the substrate moving devices 29 is the same as that of the substrate receiving / dispensing device 2 described above, and the interval is the same as that of the substrate receiving / dispensing device 2.
Inside the film forming chamber 22, the electrodes 25 a to 25 e are positioned in the guide grooves 11 of the substrate moving devices 29 as shown in FIG. 3.

  As shown in FIG. 3, a vacuum pump (deposition chamber side pressure reducing device) 34 is connected to the film forming chamber 22 via a valve 33.

Next, the moving chamber 5 and the chamber moving device 32 will be described.
As shown in FIG. 2, the moving chamber 5 has a box shape in which the top surface, the bottom surface, the left and right side surfaces, and the back surface are surrounded, and a rectangular storage chamber entrance 35 is provided on the front surface. A flange 37 is provided at the open end of the storage chamber entrance 35.

The size and shape of the storage chamber entrance / exit 35 and the flange 37 are equal to the film formation chamber entrance / exit 16 and the flange 17 of the film formation chamber 15 described above.
The storage chamber entrance / exit 35 of the moving chamber 5 has no member to shield it, and the storage chamber entrance / exit 35 is always open.

The interior of the transfer chamber 5 is a storage chamber 47 for storing the base body 46 as shown in FIG.
A substrate moving device 49 is provided inside the storage chamber 47 in the same manner as the substrate receiving / dispensing device 2 and the film forming chamber 22 described above. The number of the substrate moving devices 49 is the same as that of the substrate receiving / dispensing device 2 and the film forming chamber 22 described above, and the interval is the same as that of the substrate receiving / dispensing device 2 and the like.

Further, as shown in FIG. 6, six heaters 43a, b, c, d, e, and f are provided in the storage chamber 47 of the moving chamber 5. The structure of the six heaters 43 a, b, c, d, e, and f includes six heaters 23 a, b, c, d, e, and f arranged in the film forming chamber 22 of the film forming chamber 15 described above. It is the same. The six heaters 23a, b, c, d disposed in the film forming chamber 22 of the film forming chamber 15 are also related to the positional relationship between the six heaters 43a, b, c, d, e, f in the transfer chamber 5. , E, f.
A vacuum pump 44 is connected to the storage chamber 47 through a valve 45. The vacuum pump 44 functions as a storage chamber side pressure reducing device.

The chamber moving device 32 moves the moving chamber 5 in the row direction and in the front-rear direction, and the movement in the row direction is performed along the rail 50 as shown in FIGS. That is, it moves along the rail 50 with an electric motor (not shown).
On the other hand, it is performed along the straight guide 51 in the front-rear direction. That is, the moving chamber 5 linearly moves in the front-rear direction (the approaching / separating direction with respect to the film forming chamber 15) by a hydraulic or pneumatic cylinder (not shown).

Next, the base carrier 72 that carries the base 46 will be described.
As shown in FIG. 7, the base carrier 72 has a rectangular parallelepiped carrier base 73, and a total of eight wheels 75 are provided on both sides thereof.

Two frame bodies 77 are provided on the upper surface side of the carrier base 73 so as to face each other in parallel.
As shown in FIGS. 7 and 8, the frame body 77 is provided with two square openings 78, and a number of clips 80 are provided around the openings 78.

As shown in FIG. 8, a glass substrate as the base 46 is attached to the frame body 77 of the base carrier 72, and the clip 80 holds the two together.
Therefore, the exposed surface of the glass substrate serving as the base 46 faces the inside of the opposing frame body 77.

  Next, the overall layout of the CVD apparatus 1 will be described.

  In the CVD apparatus 1, as shown in FIG. 1, the four film forming chambers 15 constituting the film forming chamber group 3 are all arranged in a row with the film forming chamber entrances 16 facing in the same direction. The substrate receiving / dispensing device 2 is in a position aligned with the film forming chamber group 3.

As shown in FIGS. 1 and 2, the rail 50 of the chamber moving device 32 is installed along the front side of the film forming chamber group 3 and the substrate receiving / dispensing device 2. The moving chamber 5 is placed on the rail 50. The storage chamber entrance / exit 35 of the transfer chamber 5 faces the direction facing the film formation chamber entrance / exit 16 of the film formation chamber 15.
The electric motor (not shown) of the chamber moving device 32 rotates and self-runs, and the moving chamber 5 moves in the column direction of the film forming chamber group 3.
Further, when the cylinder (not shown) of the chamber moving device 32 is expanded and contracted, the moving chamber 5 moves in the approaching / separating direction with respect to the film forming chamber 15.

  Next, a CVD method using the CVD apparatus 1 will be briefly described.

  FIG. 9 is an external perspective view showing a state where the transfer chamber 5 and the film forming chamber 15 are joined. FIG. 10 is a partially broken perspective view of the moving chamber 5 and the film forming chamber 15 showing a state in which the substrate carrier 72 moves from the moving chamber 5 to the film forming chamber 15.

  As a preparation stage of the CVD method, the pressure in the film forming chambers 22 of the four film forming chambers 15 constituting the film forming chamber group 3 is reduced. Specifically, the shutter 18 of the film forming chamber entrance / exit 16 is closed, the vacuum pump (film forming chamber side pressure reducing device) 34 is started, and the valve 33 is opened to exhaust the air in the film forming chamber 22. The base 46 is attached to the base carrier 72.

  In the CVD method, first, the substrate carrier 72 is set in the substrate receiving / dispensing apparatus 2. Specifically, the substrate carrier 72 is placed on the substrate receiving / dispensing device 2, and the wheel 75 of the substrate carrier 72 is fitted between the guide grooves 11 of the substrate moving device 8 of the substrate receiving / dispensing device 2.

  Then, the substrate receiving / dispensing device 2, the transfer chamber 5, and the film forming chamber group 3 are organically operated by a control device (not shown) to form a silicon-based p layer, i layer, and n layer on the substrate 46.

More specifically, when the substrate carrier 72 is placed on the substrate receiving / dispensing device 2, the moving chamber 5 moves to the position of the substrate receiving / dispensing device 2.
Then, the five base carriers 72 are sequentially advanced and moved into the storage chamber 47 on the side of the moving chamber 5.

  When it is confirmed that all the substrate carriers 72 have moved to the moving chamber 5 side, the moving chamber 5 moves again in the row direction and stops in front of the film forming chamber 15 at the adjacent position.

  Subsequently, the cylinder of the moving chamber 5 extends, and the moving chamber moves in a direction close to the film forming chamber 15.

  Finally, the tip of the transfer chamber 5 comes into contact with the tip of the film forming chamber 15 as shown in FIGS.

  That is, the storage chamber entrance / exit 35 of the transfer chamber 5 matches the film forming chamber entrance / exit 16 of the film forming chamber 15, and the flange 37 of the transfer chamber 5 matches the flange 17 of the film forming chamber 15. The flange 37 presses the flange 17 of the film forming chamber 15.

  As described above, the film-forming chamber entrance / exit 16 of the film-forming chamber 15 is provided with an airtight shutter 18, and therefore, in the transfer chamber 5, the storage chamber 47, A closed space surrounded by is formed.

  When it is confirmed that the flange 37 of the transfer chamber 5 and the flange 17 of the film forming chamber 15 are completely connected, the vacuum pump (storage chamber side pressure reducing device) 44 is activated and the valve 45 is opened to store the above-described storage. Air is exhausted from a closed space surrounded by the chamber 47 and the shutter 18 of the film forming chamber 15, and the pressure is reduced to a vacuum.

  When the enclosed space reaches a predetermined degree of vacuum, the six heaters 43a, b, c, d, e, and f provided in the storage chamber 47 of the moving chamber 5 are heated to increase the internal substrate. 46 is heated and heated. In this CVD method, since the substrate is heated after the pressure in the chamber is reduced, an oxide film cannot be formed on the substrate surface, and a high-quality thin film can be formed.

  When it is confirmed that the substrate 46 has reached a predetermined temperature, the shutter 18 of the film forming chamber 15 is opened. Here, the film forming chamber 22 of the film forming chamber 15 is in a high vacuum state first, but as described above, air is discharged from the enclosed space surrounded by the storage chamber 47 and the shutter 18 of the film forming chamber 15. Since this part is also in a vacuum state after evacuation, the degree of vacuum in the film forming chamber 22 is maintained even if the shutter 18 of the film forming chamber 15 is opened.

  When it is confirmed that the shutter 18 is completely opened, the substrate carrier 72 is drawn into the film forming chamber 22 of the film forming chamber 15.

  There are six heaters 23a, b, c, d, e, and f inside the film forming chamber 22, and the electrodes 25a, b, c, d, and the heaters 23a, b, c, d, e, and f. Are alternately arranged, so that each of the substrates 46 mounted on the substrate carrier 72 is inserted between the heater 23 and the electrode 25.

  That is, a plurality of bases 46 are stored in the storage chamber 47 of the transfer chamber 5, and the bases 46 are arranged vertically in parallel with a predetermined interval. However, the bases in the storage chamber 47 of the transfer chamber 5 are arranged. 46 moves linearly in the surface direction and is transferred to the film forming chamber 22 of the film forming chamber 15, and each substrate 46 is inserted between the heater 23 and the electrode 25.

  When it is confirmed that all of the substrate carriers 72 are moved into the film forming chamber 22 of the film forming chamber 15 and are respectively disposed at predetermined positions, the shutter 18 of the film forming chamber 15 is closed. Then, a silicon semiconductor is formed on the base 46 of the base carrier 72 in the film forming chamber 22 of the film forming chamber 15.

  That is, a source gas is supplied into the frame 26 of the electrodes 25a, b, c, d, e and a high-frequency alternating current is applied to the electrodes 25a, b, c, d, e, so that the electrodes 25a, b, c, d, e A glow discharge is generated between the substrate carrier 72 and the source gas is decomposed to form a thin film on the surface of the substrate 46 placed vertically.

  Then, each thin film layer constituting the solar cell is formed in the film formation chamber 22 of one film formation chamber 15. That is, the solar cell is formed by laminating p-layer, i-layer, and n-layer semiconductor layers. In the CVD apparatus 1, the p-layer, i-layer, and n-layer semiconductor layers can be sequentially stacked in the film-forming chamber 22 of one film-forming chamber 15.

  Further, while the film forming process is being performed in the film forming chamber 15, the atmospheric pressure is introduced into the moving chamber 5 where the substrate carrier 72 is discharged and is empty, so that the pressure in the storage chamber 47 is increased. From the reduced pressure state to the state of equilibrium with the external pressure.

  When the pressure difference between the inside of the storage chamber 47 and the outside air is eliminated, the cylinder 71 of the chamber moving device 32 is contracted, and the moving chamber 5 is moved away from the film forming chamber 15. In other words, the transfer chamber 5, which has been joined, is separated from the film formation chamber 15. Since the transfer chamber 5 is separated from the film forming chamber 15 after the storage chamber 47 is opened to the atmosphere, the transfer chamber 5 is not subjected to atmospheric pressure, and the transfer chamber 5 is easily moved.

Then, the moving chamber 5 is self-propelled along the rail 50, moved in the row direction of the film forming chamber, and stopped again in front of the substrate receiving / dispensing apparatus 2.
Thereafter, this process is repeated, and an operation of laminating a thin film on the base 46 is performed.

Next, a cleaning method for the CVD apparatus 1 according to the embodiment of the present invention will be described.
The CVD apparatus 1 cleaning method according to the embodiment of the present invention includes a method of cleaning the film forming chamber 15 (film forming chamber 22) alone, a film forming chamber 15 (film forming chamber 22), and a transfer chamber 5 (housing). There is a method of cleaning in a state in which the chamber 47) is integrated.
First, a method for cleaning the film forming chamber 15 (film forming chamber 22) alone will be described.

As a preparatory step for the cleaning method for the film forming chamber 15 (film forming chamber 22) alone, the shutter 18 at the film forming chamber entrance / exit 16 is closed.
There are two types of processes performed by the method for cleaning the film formation chamber 22 alone: a non-plasma process and a plasma process. The film formation chamber 22 can be cleaned by sequentially performing these two types of processes. is there. The order of the non-plasma process and the plasma process is not limited, and the number of executions is not limited. Therefore, after the non-plasma process is performed, the plasma process may be performed to finish the cleaning of the film formation chamber 22, or the plasma process is performed first, and then the non-plasma process is performed to finish the cleaning of the film formation chamber 22. May be. Further, the non-plasma process and the plasma process may be alternately repeated a plurality of times. Furthermore, after repeating the non-plasma process or a plurality of times, the plasma process may be repeated a plurality of times, or after repeating the plasma process or a plurality of times, the non-plasma process may be repeated a plurality of times.
A recommended measure is a measure in which the non-plasma process and the plasma process are alternately repeated a plurality of times, and finally the plasma process is performed to finish the cleaning of the film formation chamber 22.

Here, each step will be described.
The non-plasma process is a process in which the plasma discharge is not performed in the film forming chamber 22 and the cleaning is performed only by the chemical reaction by the first reaction gas. In the non-plasma process, there are a non-flow method and a flow method as the method for injecting the first reaction gas, and either method can be adopted.
Here, the non-flow method is a measure for injecting the first reaction gas into the film formation chamber 22 and letting it elapse for a predetermined time, and then discharging the first reaction gas to clean the inside of the film formation chamber 22. On the other hand, the flow method is a measure for cleaning the film formation chamber 22 by exhausting the film formation chamber 22 while injecting the first reaction gas into the film formation chamber 22.
As described above, the method for injecting the first reaction gas is arbitrary, and the non-flow method or the flow method may be adopted. However, in this embodiment, the non-flow method is adopted. A source gas supply source 61 is used for injecting the first reaction gas, and a vacuum pump 34 is used for exhausting the film forming chamber 22.

Note that in the non-plasma process, both the non-flow method and the flow method may be performed at a pressure in the vicinity of the atmospheric pressure, but it is desirable that the inside of the film formation chamber 22 be decompressed.
The pressure (total pressure) in the film forming chamber 22 when performing the non-plasma process will be described as 1000 to 5000 (Pa: Pascal).

As the first reactive gas used in the non-plasma process, one of the three types shown in Table 1 is selected. That is, no. 1 simple fluorine gas, No. 1 No. 2 fluorine gas and nitrogen gas mixed gas; 3 chlorine trifluoride gas. In either case, a trace amount of additive gas may be included.
No. In the case of using one fluorine gas alone, the total pressure is equal to the partial pressure. That is, when a single fluorine gas is used, the partial pressure of the fluorine gas in the film forming chamber 22 is 1000 to 5000 (Pa).
No. In the mixed gas of fluorine gas and nitrogen gas, fluorine gas (F ₂ ) is a cleaning gas, and nitrogen gas (N ₂ ) is a dilution gas. The partial pressure of the fluorine gas in the film forming chamber 22 is 1000 to 5000 (Pa).
No. In No. ₃ chlorine trifluoride gas (ClF ₃ ), the chlorine trifluoride gas concentration in the film forming chamber 22 is 100 (vol%). The partial pressure of chlorine trifluoride gas in the film forming chamber 22 is 1000 to 5000 (Pa).

In the non-plasma process, the heaters 23a, b, c, d, e, and f built in the film forming chamber 22 are driven to raise the temperature in the film forming chamber 22.
The temperature in the film forming chamber 22 is desirably less than 250 degrees Celsius. A more desirable temperature range is 25 degrees Celsius to 200 degrees Celsius, and the most recommended temperature range is a range of 50 degrees Celsius to 150 degrees Celsius.
That is, when the temperature in the film forming chamber 22 reaches 250 degrees Celsius or higher, the main body of the film forming chamber 22, internal devices such as the heaters 23a, b, c, d, e, and f, and additional devices such as the vacuum pump 34, etc. There is a concern of corrosion. On the other hand, if the ambient temperature is less than 25 degrees Celsius, the activity of the reaction gas is lowered, and the deposits are not removed smoothly.
If the temperature in the film forming chamber 22 is maintained in the range of 50 degrees Celsius to 150 degrees Celsius, the precipitates are removed smoothly and the internal equipment is not damaged.

  On the other hand, the plasma process is a process of performing cleaning by a chemical reaction with the second reaction gas in a state where the inside of the film forming chamber 22 is in a plasma atmosphere. In the plasma process, the second reactive gas is injected by a flow method. A source gas supply source 61 (see FIG. 4) is used for injecting the second reaction gas, and a vacuum pump 34 (see FIG. 3) is used for exhausting the film formation chamber 22. Moreover, the high frequency alternating current power supply 60 (refer FIG. 4) is used for plasma discharge.

In the plasma process, the inside of the film forming chamber 22 is depressurized. The total pressure in the film forming chamber 22 in the plasma process is 1 (Pa) to 5000 (Pa), and the recommended total pressure is 10 (Pa) to 3000 (Pa). The most recommended total pressure is 100 (Pa) to 1000 (Pa).
In the present embodiment, the inside of the film forming chamber 22 is reduced to a total pressure of 20 to 1000 (Pa) in the plasma process.

Even when the plasma process is performed, the temperature in the film forming chamber 22 is preferably less than 250 degrees Celsius. A more desirable temperature range is 25 degrees Celsius to 200 degrees Celsius, and the most recommended temperature range is a range of 50 degrees Celsius to 150 degrees Celsius.
That is, when the temperature in the film forming chamber 22 reaches 250 degrees Celsius or higher, the main body of the film forming chamber 22, internal devices such as the heaters 23a, b, c, d, e, and f, and additional devices such as the vacuum pump 34, etc. There is a concern of corrosion. On the other hand, if the ambient temperature is less than 25 degrees Celsius, the activity of the reaction gas is lowered, and the deposits are not removed smoothly.
If the temperature in the film forming chamber 22 is maintained in the range of 50 degrees Celsius to 150 degrees Celsius, the precipitates are removed smoothly and the internal equipment is not damaged.

As the second reactive gas used in the plasma process, one is selected from the five types shown in Table 2. That is, no. No. 1 fluorine gas alone, No. 1 No. 2 mixed gas of fluorine gas and nitrogen gas, No. 2 3 carbonyl fluoride gas alone, No. 3 No. 4 mixed gas of carbonyl fluoride and oxygen gas, No. 4 One of 5 simple substances of chlorine trifluoride gas is selected. However, no. No. 1 fluorine gas alone, No. 1 The single carbonyl fluoride gas 3 may contain a small amount of additive gas. Further, other mixed gases may contain a small amount of additive gas.
In any case, the partial pressure of the reaction gas (excluding the dilution gas) in the film forming chamber 22 is 20 to 1000 (Pa).
That is, no. For one fluorine gas, the partial pressure of fluorine gas in the film forming chamber 22 is 20 to 1000 (Pa). No. The partial pressure of the fluorine gas in the film forming chamber 22 is 20 to 1000 (Pa) even in the mixed gas of fluorine gas and nitrogen gas.
Furthermore, no. 3, the partial pressure of the carbonyl fluoride gas in the film forming chamber 22 is 20 to 1000 (Pa).
No. 4, the partial pressure of the carbonyl fluoride gas in the film forming chamber 22 is 20 to 1000 (Pa).
No. 5 is used, the partial pressure of the chlorine trifluoride gas in the film forming chamber 22 is 20 to 1000 (Pa).
When a single gas is used, the partial pressure and the total pressure are equal.

In the plasma process, plasma is used in combination to increase the reactivity, so that the deposits in the film forming chamber 22 can be removed quickly and reliably.
Therefore, a wide range of unnecessary substances in the film formation chamber 22 can be removed by the non-plasma process, and the precipitates thickly stacked in the film formation chamber 22 can be quickly removed and finished by the plasma process. In the non-plasma process, the first reaction gas is supplied in a non-flow manner and only needs to be stored once, so that the amount of gas used is small. Also in the plasma process, since the finishing process can be performed quickly, the amount of gas used is small. That is, by combining the non-plasma process and the plasma process, the amount of gas used for removing unnecessary substances in the film forming chamber 22 can be reduced as compared with the conventional case. Also, the overall processing time can be shortened.

It is also recommended that the non-plasma process and the plasma process be performed in order or repeated, and then the non-plasma process is performed again at the end.
As described above, most of the unnecessary materials in the film forming chamber 22 can be removed by the non-plasma process, and the unnecessary materials in the film forming chamber 22 can be quickly removed and finished by the plasma process.

  The same effect can be expected by introducing a film material into the film forming chamber and generating plasma after the cleaning process is completed. For example, after the cleaning process is completed, plasma is generated by introducing a gas for forming a film material such as silicon into the film formation chamber. As a result, the inner surface of the film forming chamber 22 is covered with silicon, and this silicon layer functions as a protective film.

Next, a cleaning method of the film forming chamber 15 (film forming chamber 22) alone for monitoring the reaction gas discharged from the film forming chamber in the plasma process or the non-plasma process will be described.
As shown in FIG. 11, a gas analyzer 65 is provided between the valve 33 and the vacuum pump 34 in the film forming chamber 22. For example, in the plasma process, the gas analyzer 65 monitors the reaction gas discharged from the film forming chamber 22. That is, the gas analyzer 65 analyzes the components of the reaction gas, and monitors the gas components derived from the precipitates contained in the exhaust gas. Then, if the gas derived from the precipitate becomes a certain amount or less, it is considered that the cleaning is completed.

This method can also be applied in a non-plasma process. For example, during the non-plasma process, the internal gas is periodically extracted and its components are analyzed. For example, when the flow method is adopted in the non-plasma process, the cleaning is considered to be completed when the gas derived from the precipitate becomes a certain amount or less.
On the contrary, when the non-flow method is adopted, it is considered that the cleaning is completed when the gas derived from the precipitate becomes a certain amount or more.
In this manner, the cleaning state in the film forming chamber 22 can be grasped by monitoring the reaction gas discharged from the film forming chamber. As a result, the film formation chamber 22 can be prevented from being corroded by excessive cleaning.

Next, a cleaning method in which the film forming chamber 15 (film forming chamber 22) and the moving chamber 5 (housing chamber 47) are integrated will be described.
As shown in FIGS. 9 and 10, as a preparatory stage of the cleaning method in which the film forming chamber 15 (film forming chamber 22) and the moving chamber 5 (storage chamber 47) are integrated, as shown in FIGS. The storage chamber 47 is combined and integrated. At this time, the substrate carrier 72 is taken out from both the film formation chamber 22 and the storage chamber 47.

  In a state where the film formation chamber 22 and the storage chamber 47 are integrated, a non-plasma process is performed in the film formation chamber 22 as described above. As a result, the inside of the storage chamber 47 can be cleaned together with the cleaning of the film forming chamber 22. In addition, as shown in FIG. 6, six heaters 43a, b, c, d, e, and f are provided in the storage chamber 47 (the moving chamber 5). Therefore, when cleaning the storage chamber 47, the heaters 43a, b, c, d, e, and f can also be cleaned.

DESCRIPTION OF SYMBOLS 1 CVD apparatus 5 Transfer chamber 22 Deposition chamber 34 Vacuum pump (deposition chamber side decompression device)
46 Base (substrate)
47 Storage Room 60 High Frequency AC Power Supply (High Frequency Power Supply)
61 Source gas supply source (reactive gas injection device)
65 Gas analyzer

Claims (12)

In a cleaning method of a CVD apparatus having a film forming chamber equipped with a high frequency power supply device capable of plasma discharge, a film forming chamber side pressure reducing device, and a reactive gas injection device, and capable of forming a film on a substrate in the film forming chamber ,
It has a non-plasma process and a plasma process,
The non-plasma step is a step of injecting a first reaction gas into the film formation chamber and allowing a predetermined time to elapse, or a step of exhausting the film formation chamber while injecting the first reaction gas into the film formation chamber,
The plasma step is a step of exhausting the film formation chamber while injecting the second reaction gas into the film formation chamber and performing plasma discharge.
A cleaning method for a CVD apparatus, wherein the first reaction gas and the second reaction gas contain a fluorine element.   2. The CVD apparatus cleaning method according to claim 1, wherein in the non-plasma process and / or the plasma process, the temperature in the film forming chamber is adjusted to a temperature of less than 250 degrees Celsius.   3. The CVD apparatus cleaning method according to claim 1, wherein the first reaction gas is any one of fluorine gas, a mixed gas containing at least fluorine gas and nitrogen gas, and chlorine trifluoride gas. 4. .   The second reaction gas is any one of fluorine gas, a mixed gas containing at least fluorine gas and nitrogen gas, a carbonyl fluoride gas, a mixed gas containing at least carbonyl fluoride gas and oxygen gas, and chlorine trifluoride gas. The CVD apparatus cleaning method according to claim 1, wherein the CVD apparatus cleaning method is provided.   5. The partial pressure of fluorine gas in the deposition chamber when a mixed gas of fluorine gas and nitrogen gas is used in the non-plasma process is set to 1000 to 5000 Pascals. Cleaning method for CVD apparatus.   5. The CVD according to claim 1, wherein in the non-plasma process, chlorine trifluoride gas is used, and a partial pressure of the chlorine trifluoride gas in the film forming chamber is set to 1000 to 5000 Pascal. How to clean the device.   7. The plasma process according to claim 1, wherein in the plasma step, a partial pressure of the fluorine gas in the film formation chamber when a mixed gas of fluorine gas and nitrogen gas is used is set to 20 to 1000 Pascal. A cleaning method for a CVD apparatus.   7. The plasma process, wherein the partial pressure of the carbonyl fluoride gas in the film forming chamber when using a mixed gas of carbonyl fluoride gas and oxygen gas is set to 20 to 1000 Pascal. A cleaning method for a CVD apparatus according to claim 1.   7. The CVD apparatus cleaning method according to claim 1, wherein a partial pressure in the film forming chamber when chlorine trifluoride gas is used in the plasma step is 20 to 1000 Pascal.   10. The CVD apparatus cleaning method according to claim 1, wherein the plasma process is performed after the non-plasma process and the plasma process are performed once or a plurality of times.   The CVD apparatus cleaning method according to claim 1, further comprising a gas analyzer, wherein the reaction gas discharged from the film forming chamber is monitored by the gas analyzer.   The film formation chamber has a transfer chamber capable of carrying in and out the substrate, the transfer chamber has a storage chamber, and the storage chamber can be combined with the film formation chamber to integrate the chamber. The CVD apparatus cleaning method according to claim 1, wherein the non-plasma process is performed in a state where the chamber and the film formation chamber are integrated.

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