Method for cleaning filter and device for cleaning filter

Abstract

The present invention cleans a filter which is capable of removing impurities that have been mixed into a starting material gas. This method for cleaning a filter (F) includes: a purging step for removing foreign matter adhering to the filter (F) by supplying a gas to the filter (F) from a first end (E1) side of the filter (F) and purging the inside of the filter (F) through a filter surface; and a cleaning step for removing impurities and foreign matter adhering to the filter (F) by supplying a cleaning liquid to the filter (F) from a second end (E2) side of the filter (F).

Description

Filter cleaning method and filter cleaning device

[0001] The present invention relates to a filter cleaning method and a filter cleaning device.

[0002] Conventionally, it is known to produce polysilicon by supplying a raw material gas into a reactor to deposit polysilicon on a silicon core wire disposed in the reactor. Here, as disclosed in Patent Document 1, in order to prevent impurities derived from materials used in pipes and the like for forming a supply flow path for supplying the raw material gas into the reactor from entering the reactor, it is preferable to provide a filter for removing impurities mixed in the raw material gas.

[0003] International Publication No. 2021 / 065685

[0004] However, regarding the filter disclosed in Patent Document 1, a method for cleaning the filter for reuse has not been established conventionally. One aspect of the present invention aims to clean a filter capable of removing impurities mixed in a raw material gas.

[0005] In order to solve the above problems, a filter cleaning method according to one aspect of the present invention is a filter cleaning method for removing impurities mixed in a raw material gas for polysilicon deposition and foreign substances adhering to the filter after polysilicon deposition from a filter having a first end that is blocked, a second end that is opposite to the first end and is open, and a filter surface extending between the first end and the second end, the method including: a purge step of supplying a gas to the filter from the first end side and purging the inside of the filter through the filter surface to remove the foreign substances adhering to the filter; and a cleaning step of supplying a cleaning liquid to the filter from the second end side after the purge step to remove the impurities and the foreign substances adhering to the filter.

[0006] Furthermore, a filter cleaning device according to one aspect of the present invention is a filter cleaning device that removes impurities mixed in the raw material gas for polysilicon deposition and foreign matter adhering to the filter after polysilicon deposition from a filter having a closed first end, a second end opposite to the first end and open, and a filter surface extending between the first end and the second end, comprising: a gas supply unit capable of removing the foreign matter adhering to the filter by supplying gas to the filter from the first end side and purging the inside of the filter via the filter surface; and a cleaning liquid supply unit capable of removing the impurities and foreign matter adhering to the filter by supplying cleaning liquid to the filter from the second end side.

[0007] According to one aspect of the present invention, a filter capable of removing impurities mixed in the raw material gas can be cleaned.

[0008] This is a schematic diagram showing an example of a polysilicon manufacturing apparatus equipped with a filter according to an embodiment of the present invention. This is a cross-sectional view showing an example of the configuration of the filter included in the polysilicon manufacturing apparatus shown in Figure 1. This is a schematic diagram showing an example of the configuration of a filter cleaning apparatus according to an embodiment of the present invention. This is a cross-sectional view showing an example of the configuration of the holding part and storage part included in the polysilicon cleaning apparatus shown in Figure 3. This is a schematic diagram for explaining the configuration of the clamping part included in the polysilicon cleaning apparatus shown in Figure 3.

[0009] <Configuration of Polysilicon S Manufacturing Apparatus 100> First, the manner in which the filter F to be cleaned is used in the embodiment of the present invention will be described. Figure 1 is a schematic diagram showing an example of a polysilicon S manufacturing apparatus 100 equipped with a filter F according to an embodiment of the present invention. As shown in Figure 1, the polysilicon S manufacturing apparatus 100 includes a reactor 110, a supply pipe 120, a filter F, a supply nozzle 130, an electrode 140, and a discharge pipe 150. Note that the manufacturing apparatus 100 does not necessarily have to be equipped with a supply nozzle 130.

[0010] The reactor 110 has a bottom portion 111 where polysilicon S is placed, and a bell jar-type lid portion 112 that is detachably connected to the bottom portion 111. The reactor 110 contains the raw material gas G for silicon deposition with the lid portion 112 connected to the bottom portion 111. The reactor 110 may also be a batch-type reactor capable of producing multiple polysilicon S at once.

[0011] The raw material gas G is a gas for polysilicon deposition and is, for example, a gas containing silane. The silane may be, for example, tetrachlorosilane, trichlorosilane, dichlorosilane, or monochlorosilane, and generally, trichlorosilane is preferred. Alternatively, the raw material gas G may be, for example, a mixed gas of hydrogen and trichlorosilane, or a mixed gas of hydrogen, trichlorosilane, and dichlorosilane.

[0012] The bottom 111 has an inlet 113 for the raw material gas G to flow into the reactor 110 and an outlet 114 for the exhaust gas HG after the reaction in the reactor 110 to be discharged. A through hole H1 extends from the inlet 113 through the bottom 111. A through hole H2 extends from the outlet 114 through the bottom 111. In Figure 1, two inlets 113 and one outlet 114 are formed in the bottom 111, but the number of inlets 113 and outlets 114 formed in the bottom 111 is not particularly limited.

[0013] The supply piping 120 includes a first pipe 121 and a second pipe 122. One end of the first pipe 121 is connected to a gas supply unit (not shown) that supplies raw material gas G, and the other end of the first pipe 121 is connected to the second pipe 122. The raw material gas G can be supplied equally to each of the two inlets 113. In Figure 1, there are two second pipes 122, but since this is the same as the number of inlets 113, the number may be changed as appropriate to correspond to the number of inlets 113.

[0014] The second pipe 122 connects the first pipe 121 to the bottom 111. The second pipe 122 extends between the connection point between the first pipe 121 and the second pipe 122 and the end of the through hole H1 opposite to the inlet 113. The second pipe 122 may also extend between the connection point between the first pipe 121 and the second pipe 122 and the inlet 113.

[0015] The supply pipe 120 and the bottom portion 111 that forms the through hole H1 are made of, for example, stainless steel. Stainless steel is an alloy containing at least one of the constituent elements such as Fe, Ni, Cr, Mn, Cu, Ti, Mo, and Nb. The supply pipe 120 is corroded by the raw material gas G, causing impurities of the constituent elements of stainless steel to be introduced into the raw material gas G. These impurities include oxides and chlorides of the constituent elements of stainless steel.

[0016] Because the supply pipe 120 and the bottom portion 111 forming the through-hole H1 are made of stainless steel, there is a possibility that at least one of the heavy metal elements Fe, Ni, Cr, Mn, Cu, Ti, Mo, and Nb may enter the reactor 110 and contaminate the polysilicon S due to the constituent elements of stainless steel.

[0017] The supply channel for supplying the raw material gas G into the reactor 110 is formed from a supply pipe 120, an inlet 113, and a supply nozzle 130. In other words, the supply channel includes the inlet 113, and the supply pipe 120 forms the supply channel. The supply channel also includes the inlet 131 of the supply nozzle 130, that is, the tip of the supply nozzle 130.

[0018] The supply nozzle 130 is a nozzle that protrudes into the reactor 110 from the inlet 113. The supply nozzle 130 is located at the bottom 111 of the reactor 110 to allow the raw material gas G flowing in from the inlet 113 to reach the upper part of the reactor 110 and to allow the polysilicon S to grow uniformly. The supply nozzle 130 also prevents the raw material gas G from directly contacting the vicinity of the electrode 140. The supply nozzle 130 helps to prevent the polysilicon S from becoming easily broken.

[0019] The supply nozzle 130 is preferably made of a material that has high corrosion resistance to the raw material gas G, for example, carbon. The supply nozzle 130 has the shape of a nozzle, but it may also have a shape other than a nozzle, for example, it may be an orifice provided in the inlet 113.

[0020] The electrode 140 is a component for supplying power to a silicon core wire (not shown) electrically connected to the electrode 140, and is a component for heating the silicon core wire by passing current through it. At least one pair of electrodes 140 are provided at the bottom 111. The number of electrodes 140 is determined in accordance with the number of silicon core wires installed inside the reactor 110.

[0021] The discharge pipe 150 is a pipe for discharging the exhaust gas HG generated in the reactor 110 to the outside of the reactor 110. The discharge pipe 150 extends between the outside of the reactor 110 and the end of the through hole H2 opposite to the outlet 114. Alternatively, the discharge pipe 150 may extend between the outside of the reactor 110 and the outlet 114.

[0022] <Configuration of Filter F> Filter F is installed in the supply channel and is a component capable of removing impurities mixed in the raw material gas G. In other words, filter F is installed in either the supply pipe 120, the inlet 113, the supply nozzle 130, or the inlet 131. In order to minimize the amount of impurities entering the reactor 110, it is preferable that filter F be installed near the reactor 110 or inside the reactor 110 so as to be able to capture impurities generated from the material of the supply channel closest to the reactor 110, for example, it is preferable that it be installed at the inlet 113 in the supply channel.

[0023] Figure 2 is a cross-sectional view showing an example of the configuration of a filter F provided in the polysilicon S manufacturing apparatus 100 shown in Figure 1. As shown in Figure 2, the filter F has a cylindrical shape and comprises a tip portion F1, a first side wall portion F2, a filter surface F3, a second side wall portion F4, and a base portion F5. The first side wall portion F2, the filter surface F3, and the second side wall portion F4 are cylindrical in shape.

[0024] The tip portion F1 has a closed first end E1, and the shape of the tip portion F1 is tapered, narrowing in the direction from the second end E2 (described later) toward the first end E1. The first side wall portion F2 is connected to or integrated with the tip portion F1. The first side wall portion F2 is positioned between the tip portion F1 and the filter surface F3.

[0025] The filter surface F3 is provided between the first side wall portion F2 and the second side wall portion F4. The filter surface F3 may be composed of, for example, a mesh, or a sintered body of fine powder such as metal or ceramic. Alternatively, the filter surface F3 may be composed of a structure in which the mesh and the sintered body are stacked. In this case, it is preferable that the mesh is placed on the outside and the sintered body is placed on the inside.

[0026] The second side wall portion F4 is connected to or integrated with the base portion F5. The second side wall portion F4 may be detachable from the base portion F5. The second side wall portion F4 is positioned between the filter surface F3 and the base portion F5. The base portion F5 has a second end E2 that is opposite to the first end E1 and is open.

[0027] The base F5 is provided at the inlet 113 and connects the supply nozzle 130 and the second side wall F4. The supply nozzle 130 is connected to the side of the base F5 opposite to the side to which the second side wall F4 is connected. The supply nozzle 130 may be detachable from the base F5. The direction in which the raw material gas G flows is from the first end E1 to the second end E2. The filter surface F3 extends between the first side wall F2 and the second side wall F4. In other words, the filter surface F3 extends between the first end E1 and the second end E2. If the filter surface F3 has sufficient strength to prevent significant deformation or other problems caused by the gas flow during polysilicon deposition, the first side wall F2 and the second side wall F4 may be omitted, and the filter surface F3 may be directly connected to the tip F1 and the base F5.

[0028] The filter F is preferably made of a material with high corrosion resistance to the raw material gas G. The filter F is made of, for example, stainless steel containing 10% or more Ni, a corrosion-resistant material, or a ceramic. Examples of the corrosion-resistant material include Hastelloy, Inconel 600, Incoloy 800, or Incoloy 800H. Examples of the ceramic include alumina, titania, zirconia, quartz, silicon carbide, silicon nitride, or aluminum nitride. Considering economics, the filter F is preferably made of stainless steel containing 10% or more Ni, or SUS316L.

[0029] The first end E1 is positioned on the upstream side of the supply channel, and the second end E2 is positioned on the downstream side of the supply channel. The structure of the filter F is such that the first end E1 is positioned on the opposite side from the second end E2. The base F5 is attached to the inlet 113 so that the first end E1 and the second end E2 are aligned along the inner wall of the supply channel. The base F5 can be removed from the inlet 113 for cleaning the filter F.

[0030] <Method for Manufacturing Polysilicon S> Next, an example of a method for manufacturing polysilicon S will be described. First, impurities mixed in the raw material gas G are removed by a filter F. It is preferable that the removal of impurities mixed in the raw material gas G is performed immediately before the raw material gas G is supplied into the reactor 110. This makes it possible to minimize the amount of impurities that enter the reactor 110. After removing the impurities mixed in the raw material gas G, the raw material gas G from which the impurities have been removed is supplied into the reactor 110, thereby depositing polysilicon S on the silicon core wire electrically connected to the electrode 140.

[0031] As described above, after the filter F removes impurities mixed into the raw material gas G, polysilicon S precipitates. As a result, even though silane, which contains chlorine in its molecule and is corrosive, is included in the raw material gas G, the material of the supply piping 120 is eroded, rust and chlorides are formed on the surface, and even if some of the rust and chlorides mix into the raw material gas G, it is possible to prevent them from entering the reactor 110.

[0032] <Configuration of the filter F cleaning device 1> Figure 3 is a schematic diagram showing an example of the configuration of the filter F cleaning device 1 according to an embodiment of the present invention. In Figure 3, the positive X-axis direction is the direction in which the filter F is transported by the transport mechanisms 7, 11, 16, and 51, the Z-axis direction is the vertical direction, and the Y-axis direction is perpendicular to both the X-axis direction and the Z-axis direction. The X-axis direction and the Z-axis direction are perpendicular to each other. The following description is a description of the cleaning device 1, but also serves as a description of the method for cleaning the filter F.

[0033] As shown in Figure 3, the cleaning device 1 comprises a mounting section 3, 19, a transport section 5, a reversing mechanism 9, 14, a holding section 10, clamping sections 41, 171, 191, expandable sections 42, 172, 192, a supply section 80, a measuring section 200, and a discharge section 210. The cleaning device 1 is a device for cleaning filters F used in the manufacture of polysilicon S.

[0034] <Configuration of the mounting section 3 and the transport section 5> The mounting section 3 is a mounting platform or container on which multiple filters F are placed before processing by the washing device 1. The multiple filters F are placed on the mounting section 3 with their first end E1 facing upwards and their second end E2 facing downwards.

[0035] The transport unit 5 includes transport mechanisms 7, 11, 16, and 51. The transport mechanism 51 is connected to the telescopic parts 42, 172, and 192, and the transport mechanism 51 moves the telescopic parts 42, 172, and 192 in the X-axis direction. The tip of the telescopic part 42 is provided with a clamping part 41 capable of clamping the filter F, and the position of the clamping part 41 in the Z-axis direction is changed as the telescopic part 42 extends and retracts in the Z-axis direction.

[0036] Let's consider the case where the cleaning device 1 places the filter F, which is placed on the mounting section 3, onto the support section 6 located at a predetermined position on the transport mechanism 7. In this case, the transport mechanism 51 moves the telescopic section 42 to a position above the mounting section 3, and as the telescopic section 42 extends, the clamping section 41 clamps the filter F. After the clamping section 41 clamps the filter F, the telescopic section 42 retracts, and the transport mechanism 51 moves the telescopic section 42 to a position above the transport mechanism 7.

[0037] Then, the extendable portion 42 extends, and the clamping portion 41 releases its grip on the filter F, thereby positioning the filter F on the support portion 6 at a predetermined position on the transport mechanism 7. At this time, the support portion 6 supports the filter F such that the first end E1 faces upward and the second end E2 faces downward. As described above, the transport mechanism 51 transports the filter F in the positive X-axis direction by moving the clamping portion 41, which is gripping the filter F, in the positive X-axis direction. The transport mechanism 7 transports the support portion 6 that supports the filter F in the positive X-axis direction.

[0038] <Configuration of the gas supply unit 83> The supply unit 80 comprises gas supply units 83, 163, and 183, and a cleaning liquid supply unit 162. The supply unit 80 is capable of supplying cleaning liquid and gas. The gas supplied by the gas supply units 83, 163, and 183 is, for example, air or nitrogen. The gas supply unit 83 is connected to the discharge unit 81 via a hose 82. The gas supply unit 83 can discharge gas from the discharge unit 81. The discharge units 81 and 181 are, for example, elongated containers with open lower ends, and the hoses 82 and 182 extend so that the lower ends of the discharge units 81 and 181 come into contact with the support units 6 and 15, enclosing the filter F and shielding it from the outside.

[0039] After the transport mechanism 7 transports the support section 6 to a position below the discharge section 81, the gas supply section 83 supplies gas to the filter F from the first end E1 side to purge the inside of the filter F via the filter surface F3 (purging step). This allows the gas supply section 83 to remove foreign matter that adheres to the inside of the filter F after polysilicon deposition.

[0040] The foreign matter removed from the filter F by the gas supply unit 83 is discharged outside the cleaning device 1 by passing through the outlet H3 formed below the discharge unit 81. The gas that has passed through the filter F is also discharged outside the cleaning device 1 as exhaust gas by passing through the outlet H3.

[0041] The foreign matter removed from the filter F by the gas supply unit 83 is foreign matter that adhered to the filter F provided at the inlet 113 after polysilicon S was deposited on the silicon core wire during the manufacturing of polysilicon S.

[0042] The foreign matter includes by-products in the reactor 110 that fell into the filter F from the inlet 113 after the deposition of polysilicon ended and the supply of the raw material gas G stopped. Further, the foreign matter includes dust generated when taking out the polysilicon S from the reactor 110 and falling into the filter F from the inlet 113, and fine particles in the air that flowed into the filter F while the filter F was being transported from the reactor 110 to the cleaning device 1. The dust is generated in the environment where the reactor 110 is installed.

[0043] On the other hand, the gas supplied by the gas supply unit 83 is supplied in the same direction as the supply direction of the raw material gas G supplied during the polysilicon deposition, that is, in the direction from the first end E1 to the second end E2. Therefore, the impurities in the raw material gas G collected outside the filter F and the fine particles in the air adhering to the outside of the filter F while the filter F is being transported from the reactor 110 to the cleaning device 1 cannot pass through the filter surface F3, and thus cannot be removed when the gas supply unit 83 supplies gas to the filter F.

[0044] In the above, the transport unit 5 transports the filter F from the standby position where the filter F waits in the placement unit 3 by the transport mechanisms 7 and 51 to the purge position where the purge of the inside of the filter F is performed by the gas supply unit 83.

[0045] <Configuration of the inversion mechanism 9> After the gas supply unit 83 removes the foreign matter adhering to the inside of the filter F, the transport mechanism 7 transports the support portion 6 to a position below the inversion mechanism 9. The inversion mechanism 9 includes a first clamping portion 91 and a second clamping portion 92. The first clamping portion 91 clamps the first end E1 side of the filter F, and the second clamping portion 92 clamps the second end E2 side of the filter F. Specifically, the first clamping portion 91 clamps the first side wall portion F2 of the filter F, and the second clamping portion 92 clamps the second side wall portion F4 of the filter F.

[0046] In this state, the inversion mechanism 9 inverts the first end E1 and the second end E2 of the filter F by inverting the first clamping part 91 and the second clamping part 92 (inversion process). Then, the transport mechanism 51 moves the telescopic part 172 to a position above the inversion mechanism 9. As the telescopic part 172 extends, the clamping part 171 clamps the second end E2 side of the filter F. Specifically, the clamping part 171 clamps the base part F5 of the filter F. The clamping part 171 has the same function as the clamping part 41, and the telescopic part 172 has the same function as the telescopic part 42.

[0047] <Configuration of the cleaning liquid supply part 162 and the gas supply part 163> The cleaning liquid supply part 162 is connected to a pipe P2 branched from the pipe P1. The gas supply part 163 is connected to a pipe P3 branched from the pipe P1. The pipe P1 branches into the pipe P2 and the pipe P3. The pipe P1 is connected to the discharge part 161 via a hose 164.

[0048] After the clamping part 171 clamps the filter F, the telescopic part 172 contracts, and the transport mechanism 51 moves the telescopic part 172 to a position above the holding part 10 at a predetermined position of the transport mechanism 11. Then, as the telescopic part 172 extends, the clamping part 171 releases the state of clamping the filter F, thereby causing the filter F to be held by the holding part 10 at a predetermined position of the transport mechanism 11. In other words, the clamping part 171 accommodates the filter F in the holding part 10 by releasing the state of clamping the filter F (accommodation process). The holding part 10 is an example of the accommodation part.

[0049] At this time, the holding part 10 holds the filter F such that the second end E2 faces upward and the first end E1 faces downward. As described above, the transport mechanism 51 transports the filter F in the positive X-axis direction by moving the clamping part 171 in the state of clamping the filter F in the positive X-axis direction. The transport mechanism 11 transports the holding part 10 holding the filter F to a position below the discharge part 161.

[0050] <Configuration of the holding section 10 and storage section 20> Figure 4 is a cross-sectional view showing an example of the configuration of the holding section 10 and storage section 20 provided in the cleaning device 1 shown in Figure 3. As indicated by reference numeral 401 in Figure 4, the holding section 10 includes a side wall section 101 and an opening / closing section 102. The opening / closing section 102 is openable and closable relative to the side wall section 101, and when the opening / closing section 102 is open, the filter F is housed inside the holding section 10 from the outside by the clamping section 171. The holding section 10 forms a housing space SP in which the filter F is housed. An inlet 102A is formed in the opening / closing section 102 for gas and cleaning liquid to flow into the holding section 10. The holding section 10 may also be configured without the opening / closing section 102, with the lower end of the discharge section 161 directly connected to the upper surface of the side wall section 101.

[0051] A protruding portion 101P is provided in an annular shape on the inner wall 101W of the side wall portion 101. The holding portion 10 holds the second end E2 side of the filter F, that is, the base portion F5 of the filter F, by sandwiching the base portion F5 of the filter F between the protruding portion 101P and the opening / closing portion 102.

[0052] At this point, when the clamping portion 171 releases its grip on the filter F, the opening / closing portion 102 is in the open position, the filter F falls from the clamping portion 171 toward the holding portion 10, and the base portion F5 is positioned on the protruding portion 101P. Then, the opening / closing portion 102 closes, and the base portion F5 is sandwiched between the protruding portion 101P and the opening / closing portion 102.

[0053] The storage section 20 is positioned to surround the filter surface F3 of the filter F, which is held by the holding section 10, from the outside of the filter F. Specifically, the storage section 20 is positioned to surround the tip F1, the first side wall F2, and the filter surface F3 of the filter F. The storage section 20 has side walls 21 and a bottom 22.

[0054] The side wall 21 of the storage section 20 is positioned between the filter surface F3 and the inner wall 101W of the side wall 101 in the storage space SP. The bottom 22 of the storage section 20 is, for example, an orifice, facing the tip F1 of the filter F, and is formed along the tapered shape of the tip F1. An opening 24 is formed in the bottom 22 of the storage section 20 facing the first end E1 of the filter F.

[0055] A gap IS is formed between the part of the holding portion 10 that holds the second end E2 side of the filter F and the upper part 23 of the storage portion 20 on the opposite side of the bottom portion 22. In other words, a gap IS is formed between the protruding portion 101P and the upper part 23. An outlet 101A is formed below the holding portion 10.

[0056] The storage section 20 has a tapered shape that narrows in the direction from the upper part 23 toward the opening 24. Specifically, the storage section 20 has a tapered shape because the bottom part 22 of the storage section 20 is formed along the tapered shape of the tip part F1. For example, if the shape of the tip part F1, the first side wall part F2, and the filter surface F3 of the filter F is a tapered shape that narrows in the direction from the second end E2 toward the first end E1, the overall shape of the storage section 20 may also be tapered.

[0057] <Cleaning of Filter F> In Figure 3, consider the case where the transport mechanism 11 transports the holding part 10, which holds the filter F, to a position below the discharge part 161, and then the cleaning liquid supply unit 162 supplies cleaning liquid into the filter F from the second end E2 side of the filter F held by the holding part 10 (cleaning process). In this case, the cleaning liquid supply unit 162 discharges cleaning liquid from the discharge part 161 via the pipes P1, P2 and hose 164.

[0058] Furthermore, as shown by reference numeral 402 in Figure 4, cleaning liquid L is supplied into the filter F from the inlet 102A. At this time, the storage section 20 stores the cleaning liquid L that flows out of the filter F through the filter surface F3. In addition, the tapered shape of the storage section 20 makes it easier to temporarily store the cleaning liquid L inside the filter F and outside the filter surface F3.

[0059] The cleaning liquid L that flows out from inside the filter F flows between the filter F and the side wall 21, and also flows between the tip F1 and the bottom 22, and flows out to the outside of the storage section 20 from the opening 24. The cleaning liquid L that flows out from the opening 24 is discharged to the outside of the holding section 10 from the outlet 101A. Here, the cleaning liquid supply unit 162 supplies cleaning liquid L such that the amount of cleaning liquid L supplied from the inlet 102A is greater than the amount of cleaning liquid L flowing out from the opening 24, so that cleaning liquid L is stored in the storage section 20.

[0060] If the amount of cleaning liquid L stored in the storage section 20 exceeds the storage capacity of the storage section 20, the cleaning liquid L will flow out from the gap IS between the protruding portion 101P and the upper part 23, as shown by reference numeral 403 in Figure 4. In this case, the entire tip portion F1, the first side wall portion F2, and the filter surface F3 will be immersed in the cleaning liquid L. This allows the cleaning liquid L to flow over the entire filter surface F3, thoroughly washing away impurities from the raw material gas G adhering to the outside of the filter F, as well as fine particles from the air adhering to the outside of the filter F while the filter F is being transported to the cleaning device 1. Furthermore, hydrochloric acid and silica produced when the raw material gas G adsorbed on the filter F reacts with air or the cleaning liquid L can be washed away, preventing rusting and blockage of the tip portion F1, the first side wall portion F2, and the filter surface F3.

[0061] The cleaning liquid L flowing out from the gap IS flows between the side wall 21 of the storage section 20 and the inner wall 101W of the side wall section 101, and is discharged to the outside of the holding section 10 from the outlet 101A. The cleaning liquid L discharged from the outlet 101A is then discharged as waste liquid to the outside of the cleaning device 1 by passing through the outlet H4 formed below the discharge section 161, as shown in Figure 3.

[0062] As described above, the cleaning fluid supply unit 162 is capable of cleaning the outside of the filter F by supplying cleaning fluid L to the filter F from the second end E2 side. As previously mentioned, by supplying gas to the filter F from the first end E1 side to purge the inside of the filter F, foreign matter adhering to the inside of the filter F can be removed from the second end E2, which is opposite to the first end E1, before the outside of the filter F is cleaned with the cleaning fluid L. Therefore, the filter F can be cleaned with the cleaning fluid L when no foreign matter is adhering to the inside of the filter F.

[0063] Furthermore, by supplying cleaning solution L to the filter F from the second end E2 side, the cleaning solution L can be discharged from inside the filter F to outside the filter F via the filter surface F3, thereby removing impurities and foreign matter adhering to the outside of the filter F. Therefore, both the inside and outside surfaces of the filter F can be efficiently cleaned. When manufacturing polysilicon S, using a filter F cleaned in this manner prevents blockage due to the accumulation of collected material in the filter F, prevents impurities and foreign matter from entering the reactor 110, and achieves the deposition of polysilicon S with minimal contamination.

[0064] The storage section 20 allows for the temporary storage of cleaning liquid L inside the filter F and outside the filter surface F3. Furthermore, the cleaning liquid L present at the bottom 22 of the storage section 20 is allowed to flow out through the opening 24, while the filter is being cleaned and the cleaning liquid L is being stored in the storage section 20. Any cleaning liquid L exceeding the storage capacity of the storage section 20 can be allowed to flow out through the gap IS between the part of the holding section 10 that holds the filter F and the upper part 23 of the storage section 20. Therefore, the filter F can be cleaned efficiently.

[0065] Furthermore, the discharge port 101A discharges the cleaning liquid L flowing out from the opening 24, the cleaning liquid L that flows out from the gap IS in excess of the storage capacity of the storage section 20, and the cleaning liquid L that flows between the side wall 21 of the storage section 20 and the inner wall 101W of the holding section 10, to the outside of the holding section 10. As a result, the cleaning liquid L that flows out from the gap IS in excess of the storage capacity of the storage section 20 flows between the side wall 21 of the storage section 20 and the inner wall 101W of the holding section 10, and can be discharged to the outside of the holding section 10 through the discharge port 101A formed below the holding section 10. Therefore, it is possible to prevent the cleaning liquid L from splashing to the sides of the holding section 10.

[0066] The cleaning solution L for the filter F used in the polysilicon S manufacturing apparatus 100 is preferably pure water. A gas containing silane as a raw material gas G is adsorbed on the surface of the filter F, and reacts with moisture in the air and the cleaning solution L that the filter F comes into contact with during transport to the cleaning apparatus 1 to form hydrochloric acid and silica particles. Organic solvents with low surface tension that make it easy to clean these, and alkaline solutions that neutralize hydrochloric acid and dissolve silica are useful in terms of cleaning efficiency, but the carbon atoms and alkali metal elements they possess may remain on the surface of the filter F and become a new source of contamination for the polysilicon S when the filter F is reused.

[0067] In the cleaning solution L supplied by the cleaning solution supply unit 162, the sum of the concentrations of Fe, Cr, Ni, Cu, Zn, and Na is preferably 0.1 ppbw or less. Since the cleaning solution supply unit 162 supplies the cleaning solution L into the filter F from the second end E2 side of the filter F, these metal elements remain in the filter F. These residues will be mixed with the raw material gas G during the next polysilicon deposition and scattered into the reactor 110, leading to contamination of the polysilicon S, so it is necessary to increase the purity of the cleaning solution L.

[0068] The cleaning liquid supply unit 162 supplies cleaning liquid L to the filter F housed in the holding unit 10. This allows the cleaning liquid L to spread around the filter F, enabling efficient cleaning of the filter F.

[0069] <Drying of Filter F> After the cleaning liquid supply unit 162 supplies cleaning liquid L into the filter F, the gas supply unit 163 discharges gas from the discharge unit 161 via the pipes P1, P3 and hose 164. In other words, the gas supply unit 163 supplies gas into the filter F from the second end E2 side of the filter F held by the holding unit 10 (drying process).

[0070] In other words, the gas supply unit 163 supplies gas into the filter F from the second end E2 side of the filter F housed in the holding unit 10. This dries the filter F. As a result, the gas supply unit 163 can spread the gas around the filter F, allowing the filter F to be dried efficiently. Specifically, the gas supply unit 163 supplies gas into the filter F, whose filter surface F3 is surrounded by the storage unit 20, thereby spreading the gas to the outside of the filter surface F3. The gas that has passed through the filter F is discharged as exhaust gas through the outlet H4 to the outside of the cleaning device 1.

[0071] Furthermore, as the gas supplied by the gas supply units 83, 163, and 183, in order to prevent the filter F from becoming clogged with particles, a gas containing 3,000 or fewer particles with a particle size of 0.5 μm or larger per cubic foot (CF) is generally used, and in the cleaning process of the filter F, which exhibits a high collection efficiency for submicron diameter particles, a gas with 100 particles or less per CF is preferably used.

[0072] In the above configuration, the transport unit 5, using transport mechanisms 7, 11, and 51, transports the filter F from the purging position where the gas supply unit 83 performs purging of the filter F to the cleaning position where the cleaning liquid supply unit 162 cleans the filter F. This cleaning position is the same as the drying position where the gas supply unit 163 dries the filter F.

[0073] The cleaning solution L used to clean the filter F in the polysilicon S manufacturing apparatus 100 is often acidic, and it is anticipated that it may be scattered into the cleaning apparatus 1 other than the discharge port H4 by gas blowing during the drying process. If corrosion occurs on the parts inside the cleaning apparatus 1 due to this scattered liquid, these will become new sources of contamination, leading to a problem of reduced cleaning effectiveness.

[0074] To address this problem, it is desirable to use metals with high corrosion resistance to hydrochloric acid for parts exposed to the atmosphere inside the cleaning device 1, to apply a resin coating to parts for which these materials cannot be used, or to wrap resin tape around such parts. Furthermore, since the splashing of acidic liquid is dangerous to surrounding workers, it is preferable to provide a cover around the cleaning device 1 and to have the inside constantly ventilated with gas whose cleanliness is controlled, similar to the gas used in the gas supply units 83, 163, and 183.

[0075] <Configuration of the inversion mechanism 14> After the gas supply unit 163 supplies gas to the filter F and completes the drying process, the holding unit 10 and the discharge unit 161 are separated and the opening / closing unit 102 opens, exposing the base F5 of the filter F in the holding unit 10. In this state, the transport mechanism 11 transports the holding unit 10 that holds the filter F to a position on the positive X-axis side from below the discharge unit 161, that is, to a position where the clamping unit 171 can clamp the filter F. The telescopic unit 172 extends to clamp the filter F to the clamping unit 171, and in this state, the telescopic unit 172 retracts, pulling the filter F out of the holding unit 10. After that, the transport mechanism 51 transports it to a position above the inversion mechanism 14, and the telescopic unit 172 extends to lower the filter F to a position where the inversion mechanism 14 can clamp it. The inversion mechanism 14 includes a first clamping unit 141 and a second clamping unit 142. The first clamping portion 141 clamps the second end E2 side of the filter F, and the second clamping portion 142 clamps the first end E1 side of the filter F. Specifically, the first clamping portion 141 clamps the second side wall portion F4 of the filter F, and the second clamping portion 142 clamps the first side wall portion F2 of the filter F. After the reversing mechanism 14 has clamped the filter F, the clamping portion 171 releases the clamp, retracts the telescopic portion 172, and retracts from above the reversing mechanism 14 in the negative X-axis direction.

[0076] In this state, the reversing mechanism 14 reverses the first clamping portion 141 and the second clamping portion 142, thereby reversing the first end E1 and the second end E2 of the filter F. Then, the transport mechanism 51 moves the telescopic portion 192 to a position above the reversing mechanism 14, and as the telescopic portion 192 extends, the clamping portion 191 clamps the first end E1 side of the filter F. Specifically, the clamping portion 191 clamps the first side wall portion F2 of the filter F. The clamping portion 191 has the same function as the clamping portion 41, and the telescopic portion 192 has the same function as the telescopic portion 42.

[0077] After the clamping portion 191 grips the filter F, the telescopic portion 192 retracts, and the transport mechanism 51 moves the telescopic portion 192 to a position above the support portion 15 located in a predetermined position on the transport mechanism 16. Then, the telescopic portion 192 extends, and the clamping portion 191 releases its grip on the filter F, thereby allowing the filter F to be supported by the support portion 15 located in a predetermined position on the transport mechanism 16.

[0078] At this time, the support portion 15 supports the filter F such that the first end E1 faces upward and the second end E2 faces downward. As described above, the transport mechanism 51 transports the filter F in the positive X-axis direction by moving the clamping portion 191, which is holding the filter F, in the positive X-axis direction. The transport mechanism 16 transports the support portion 15, which is supporting the filter F, to a position below the discharge portion 181.

[0079] <Configuration of the gas supply unit 183> The gas supply unit 183 is connected to the discharge unit 181 via a hose 182. The gas supply unit 183 can discharge gas from the discharge unit 181. After the transport mechanism 16 transports the support unit 15 to a position below the discharge unit 181, the gas supply unit 183 supplies gas to the filter F from the first end E1 side.

[0080] As a result, even if foreign matter originating from the cleaning solution L and foreign matter originating from the gas used in the drying process is attached to the filter F, the gas supply unit 183 removes the foreign matter from the second end E2, thereby preventing these foreign matter from mixing with the raw material gas G and flowing out into the reactor 110 when the filter F is reused. The foreign matter removed from the filter F by the gas supply unit 183 is discharged outside the cleaning device 1 by passing through the discharge port H5 formed below the discharge unit 181.

[0081] Furthermore, since the gas supply unit 183 supplies gas to the filter F from the first end E1 side, the direction in which the raw material gas G passes through the filter F during the production of polysilicon S is the same as the direction in which the gas supply unit 183 supplies gas to the filter F. Therefore, measurements by the measurement unit 200, described later, can be performed according to the conditions under which the filter F is used during the production of polysilicon S.

[0082] <Configuration of the Measurement Unit 200> The measurement unit 200 comprises a particle measurement unit 201, a first pressure measurement unit 202, and a second pressure measurement unit 203. When the gas supply unit 183 supplies gas to the filter F, the particle measurement unit 201 measures the particles contained in the gas that has passed through the filter F (particle measurement process).

[0083] Specifically, the particle measuring unit 201 measures the number of particles contained in the gas that has passed through the filter F. The unit of measurement for the number of particles is [particles / CF (cubic feet)]. The particle measuring unit 201 is located inside the support unit 15 or at the outlet H5. By measuring the particles, it is possible to confirm whether impurities and foreign matter have adhered to the filter F after it has been dried, thereby maintaining the quality of the raw material gas G that passes through the filter F.

[0084] Furthermore, when the gas supply unit 183 supplies gas to the filter F, the first pressure measuring unit 202 measures the pressure of the gas at the first end E1 of the filter F, and the second pressure measuring unit 203 measures the pressure of the gas at the second end E2 of the filter F (pressure measurement step). The first pressure measuring unit 202 is located between the discharge unit 181 and the first end E1 of the filter F, and the second pressure measuring unit 203 is located inside the support unit 15 or at the outlet H5. If the discharge unit 181 is a hollow container that encloses the filter F through the expansion and contraction of the hose 182, the first pressure measuring unit 202 may be located within the gas flow path of the discharge unit 181. In the pressure measurement process, the gas supply amount is preferably such that the difference in numerical pressure measurements (pressure loss) obtained by subtracting the pressure of the gas at the second end E2 side measured by the second pressure measurement unit 203 from the pressure of the gas at the first end E1 side of the filter F measured by the first pressure measurement unit 202 is equal to or greater than the maximum pressure loss that occurs in a normal filter F during polysilicon deposition. This maximum pressure loss is the maximum value of the pressure loss that occurs in a normal filter F, such as an unused filter F.

[0085] The first pressure measuring unit 202 and the second pressure measuring unit 203 measure the gas pressure after the particle measuring unit 201 measures the particles. Alternatively, the first pressure measuring unit 202 and the second pressure measuring unit 203 may measure the gas pressure before the particle measuring unit 201 measures the particles, or simultaneously with the particle measuring unit 201 measuring the particles.

[0086] After drying the filter F, the gas pressure at the first end E1 and the gas pressure at the second end E2 can be measured to confirm whether any impurities remain in the filter F and whether the filter F is damaged. This ensures that the quality of the raw material gas G passing through the filter F is maintained.

[0087] As described above, the transport unit 5 transports the filter F from the cleaning position where the filter F is cleaned by the cleaning liquid supply unit 162 to the measurement position where the measurement is performed by the measurement unit 200, using the transport mechanisms 11, 16, and 51. The measurement performed by the measurement unit 200 is performed by the particle measurement unit 201, the first pressure measurement unit 202, and the second pressure measurement unit 203.

[0088] After the first pressure measuring unit 202 and the second pressure measuring unit 203 measure the pressure of the gas, the transport mechanism 16 transports the support unit 15 that supports the filter F in the positive X-axis direction. Then, the transport mechanism 51 moves the expandable part 192 to a position above the support unit 15 transported by the transport mechanism 16, and as the expandable part 192 extends, the clamping part 191 clamps the first end E1 side of the filter F.

[0089] <Configuration of the mounting section 19> After the clamping section 191 clamps the filter F, the telescopic section 192 retracts, and the transport mechanism 51 moves the telescopic section 192 to a position above a predetermined position on the mounting section 19 or on another mounting section (not shown), based on the control of the unloading section 210, which will be described later. Then, the telescopic section 192 extends, and the clamping section 191 releases its grip on the filter F, thereby placing the filter F on the mounting section 19 or on another mounting section.

[0090] At this time, the filter F is placed on the mounting section 19 or the other mounting section with its first end E1 facing upwards and its second end E2 facing downwards. The mounting section 19 and the other mounting section are mounting stands or containers on which multiple filters F are placed after being processed by the washing device 1.

[0091] <Configuration of the unloading unit 210> Based on the measurement results from the measuring unit 200, the unloading unit 210 controls the transport unit 5 to distribute the destinations of multiple filters F to a first unloading position and a second unloading position different from the first unloading position. The unloading unit 210 is a control device that controls the transport unit 5, and is, for example, a CPU (Central Processing Unit). The first unloading position is a position on the mounting unit 19, and the second unloading position is a position on the other mounting unit.

[0092] If the number of particles measured by the particle measuring unit 201 is less than or equal to a predetermined number, the discharge unit 210 sets the destination of the filter F to the first discharge position. On the other hand, if the number of particles measured by the particle measuring unit 201 is greater than the predetermined number, the discharge unit 210 sets the destination of the filter F to the second discharge position. The particle size of the particles to be measured by the particle measuring unit 201 is determined based on the mesh size of the filter F, but in the case of a filter for precipitation of polysilicon S, it is preferably 0.5 μm or larger. The predetermined number is, for example, the number of particles measured on an unused filter F.

[0093] If the number of particles is less than or equal to a predetermined number, there is a high probability that the filter F is undamaged, and the discharge unit 210 can discharge the filter F that is likely to be undamaged to the mounting unit 19. On the other hand, if the number of particles is greater than the predetermined number, there is a high probability that the filter F is damaged, and the discharge unit 210 can discharge the filter F that is likely to be damaged to a mounting unit other than the mounting unit 19.

[0094] Furthermore, the discharge unit 210 calculates the pressure loss of the filter F based on the pressure of the gas at the first end E1 of the filter F, measured by the first pressure measuring unit 202, and the pressure of the gas at the second end E2 of the filter F, measured by the second pressure measuring unit 203.

[0095] The discharge unit 210 sets the destination of the filter F to the first discharge position if the pressure loss amount of the filter F is within a predetermined range. On the other hand, the discharge unit 210 sets the destination of the filter F to the second discharge position if the pressure loss amount of the filter F is outside the predetermined range. The above predetermined range is, for example, a range calculated based on the pressure loss amount measured for an unused filter F.

[0096] If the pressure loss of filter F is within a predetermined range, there is a high probability that no impurities or foreign matter are attached to filter F and that it is undamaged, and the discharge unit 210 can discharge such filter F to the mounting unit 19. On the other hand, if the pressure loss of filter F is outside the predetermined range, there is a high probability that impurities or foreign matter are attached to filter F or that it is damaged, and the discharge unit 210 can discharge such filter F to a mounting unit other than the mounting unit 19.

[0097] In this way, the discharge unit 210 sorts and discharges multiple filters F based on the measurement results from the measurement unit 200. This allows for sorting, for example, between filters F that are free of impurities and foreign matter and undamaged, and filters F that are contaminated with impurities or foreign matter, or are damaged. By reusing only the filters F that are determined to be free of impurities and foreign matter and undamaged, it is possible to prevent impurities and foreign matter from entering the reactor 110, thereby achieving the deposition of polysilicon S with minimal contamination. Filters F that are determined to be contaminated with impurities or foreign matter, or are damaged, are isolated at a different discharge destination. This prevents the situation where they are reused without being detected, allowing impurities to enter the reactor 110 and contaminating the polysilicon S, and allows for measures such as re-cleaning or repair and maintenance to be taken for reuse based on the results of inspection by a person or machine.

[0098] <Detailed Configuration of Clamping Section 41> Figure 5 is a schematic diagram illustrating the configuration of the clamping section 41 provided in the cleaning device 1 shown in Figure 3. Reference numeral 501 in Figure 5 indicates a clamping section 45 for comparison with the clamping section 41. The clamping section 45 comprises tip sections 451A and 451B, side plates 452A and 452B, and a top plate 453.

[0099] The tip portions 451A and 451B make surface contact with the first side wall portion F2 of the filter F when the clamping portion 45 is clamping the filter F. The tip portion 451A is connected to the top plate 453 via the side plate 452A, and the tip portion 451B is connected to the top plate 453 via the side plate 452B. The top plate 453 is connected to the telescopic portion 42. The clamping portion 45 can change the distance between the side plates 452A and 452B, and the filter F can be clamped by the tip portions 451A and 451B.

[0100] Since the tip portions 451A and 451B make surface contact with the filter F, if the filter surface F3 of the filter F is bent, the base portion F5 of the filter F will be significantly offset from the central axis CA of the telescopic portion 42 while the clamping portion 45 is clamping the filter F. Therefore, the filter F cannot be stably positioned in the predetermined location of the transport mechanism 7.

[0101] On the other hand, as shown by reference numeral 502 in Figure 5, the clamping portion 41 comprises tip portions 411A and 411B, side plates 412A and 412B, and a top plate 413. The tip portions 411A and 411B make point contact with the first side wall portion F2 of the filter F when the clamping portion 41 is clamping the filter F. The shape of the tip portions 411A and 411B is a shape having at least one protruding portion, or a shape having at least one curved surface portion. The curved surface portion is, for example, a part of a sphere.

[0102] The tip portion 411A is connected to the top plate 413 via the side plate 412A, and the tip portion 411B is connected to the top plate 413 via the side plate 412B. The top plate 413 is connected to the telescopic portion 42. The clamping portion 41 can change the distance between the side plates 412A and 412B, and the filter F can be clamped between the tip portions 411A and 411B.

[0103] Because the clamping portion 41 has tip portions 411A and 411B that make point contact with the filter F, even when the filter surface F3 of the filter F is bent, the base portion F5 of the filter F does not deviate significantly from the central axis CA of the telescopic portion 42 due to gravity acting on the filter F. Therefore, the filter F can be stably positioned in the predetermined location of the transport mechanism 7, and the cleaning process of the filter F can be carried out efficiently. The clamping portions 171 and 191 have the same structure as the clamping portion 41 and are equipped with tip portions that make point contact with the first side wall portion F2 of the filter F.

[0104] While employing a clamping mechanism that grips the filter at point contact as described above significantly improves installation errors from a predetermined position, it is still possible that the filter F may be transported to a position with an unacceptable error depending on the amount of deformation of the filter. Furthermore, if the task of loading the filter F into the mounting section 3 before cleaning is performed manually, there is a possibility of installation errors due to human error. To address these installation abnormalities, it is preferable that the cleaning device 1 be equipped with a system that, for example, installs a laser-type detector inside the cleaning device 1 to detect installation abnormalities when the deviation from the installation position exceeds an acceptable value, issues an alarm to prompt the worker to correct the installation position, or automatically removes the filter F that failed to be installed from the cleaning process line.

[0105] <Modification 1> The storage section 20 may have multiple openings instead of one opening 24, as long as the amount of cleaning liquid L flowing out of the storage section 20 is less than the amount of cleaning liquid L supplied to the storage section 20. In this case, the bottom 22 may extend in a plane perpendicular to the direction from the second end E2 to the first end E1 instead of being tapered, and multiple openings will be formed in the bottom 22.

[0106] <Modification 2> The gas supply unit 163 may dry the filter F by supplying gas to the filter F from the first end E1 side of the filter F. In this case, the clamping unit 171 removes the filter F from the holding unit 10, the reversing mechanism 14 inverts the filter F, and the filter F is supported by a support unit (not shown). Then, the gas supply unit 163 supplies gas to the filter F supported by the support unit using a hose and a discharge unit (not shown). Alternatively, the cleaning device 1 may use the support unit 15 as the destination for transporting the filter F and perform some or all of the drying process, particle measurement process, and pressure measurement process by the gas supply unit 183. In this case, it is desirable to provide a mechanism to protect the measurement units related to particle measurement and pressure measurement from the effects of cleaning liquid and moisture.

[0107] <Modification 3> In the above description, the cleaning liquid L supplied by the cleaning liquid supply unit 162 and the gas supplied by the gas supply unit 163 are both discharged from the discharge unit 161. However, the cleaning liquid L and the gas may be discharged from separate discharge units.

[0108] <Modification 4> In Figure 3, the transport section 5, clamping sections 41, 171, 191, expandable sections 42, 172, 192, and reversing mechanisms 9, 14 may be arranged in a plurality in the Y-axis direction. In this case, the cleaning device 1 performs cleaning of multiple filters F in parallel by transporting the filters F along a plurality of transport paths formed in the Y-axis direction.

[0109] <Modification 5> The measuring unit 200 may include a particle measuring unit 201, but may not include a first pressure measuring unit 202 and a second pressure measuring unit 203. Alternatively, the measuring unit 200 may not include a particle measuring unit 201, but may include a first pressure measuring unit 202 and a second pressure measuring unit 203.

[0110] Furthermore, the measuring unit 200 may be equipped with one pressure measuring unit instead of the first pressure measuring unit 202 and the second pressure measuring unit 203. In this case, a moving mechanism (not shown) provided by the cleaning device 1 may move the one pressure measuring unit between a first position between the discharge unit 181 and the first end E1 of the filter F and a second position inside the discharge port H5.

[0111] Alternatively, the measuring unit 200 may be a single measuring unit capable of measuring particles contained in the gas that has passed through the filter F, the pressure of the gas at the first end E1 of the filter F, and the pressure of the gas at the second end E2 of the filter F.

[0112] Therefore, when gas is supplied to the filter F, the measuring unit 200 performs at least one of the following: measuring the particles contained in the gas that has passed through the filter F, measuring the pressure of the gas at the first end E1 of the filter F, and measuring the pressure of the gas at the second end E2 of the filter F.

[0113] In this case, the measurement by the measuring unit 200 may be a measurement of particles, or it may be a measurement of the gas pressure at the first end E1 side of the filter F, and the gas pressure at the second end E2 side of the filter F. Alternatively, the measurement by the measuring unit 200 may be a measurement of particles, the gas pressure at the first end E1 side of the filter F, and the gas pressure at the second end E2 side of the filter F, all of these.

[0114] <Modification 6> In the method for cleaning the filter F, at least a portion of the processes described above, which are performed by the cleaning device 1, may be performed by a person. Specifically, the conveying process of the filter F by the conveying unit 5 and the clamping units 41, 171, 191, and the gas supply process by the gas supply units 83, 163, 183 may be performed by a person. In addition, the inversion process of the filter F by the inversion mechanisms 9, 14, the supply process of the cleaning liquid L by the cleaning liquid supply unit 162, the measurement process by the measuring unit 200, and the discharge process by the discharge unit 210 may be performed by a person.

[0115] The frequency of the cleaning process, which is carried out using some or all of the cleaning apparatus and cleaning method described above, can be determined, for example, based on the allowable range of the pressure loss that increases as impurities in the raw material gas G accumulate on the filter F in roughly proportion to the flow rate. However, it is preferable that this cleaning process be carried out every time after the precipitation of polysilicon S is completed, for the purpose of preventing foreign matter in the reactor 110 that falls into the filter F after the precipitation of polysilicon S from affecting the subsequent precipitation of polysilicon S, and for the purpose of detecting damage to the filter F early and preventing contamination of polysilicon S.

[0116] <Additional Notes> The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the multiple technical means disclosed in the embodiments are also included in the technical scope of the present invention.

[0117] 1 Washing device 5 Conveying section 9, 14 Reversing mechanism 10 Holding section 20 Storage section 21 Side wall 22 Bottom section 23 Top section 24 Opening 41, 171, 191 Clamping section 80 Supply section 83, 163, 183 Gas supply section 101A Outlet 101W Inner wall 162 Washing liquid supply section 200 Measurement section 210 Discharge section 411A, 411B Tip section E1 First end E2 Second end F Filter F3 Filter surface G Raw material gas IS Gap L Washing liquid SP Storage space

Claims

1. A method for cleaning a filter having a first closed end, a second open end on the opposite side of the first end, and a filter surface extending between the first and second ends, the method for cleaning a filter to remove impurities mixed in a raw material gas for polysilicon deposition and foreign matter adhering to the filter after polysilicon deposition, comprising: a purging step of supplying gas to the filter from the first end side to purge the inside of the filter via the filter surface to remove the foreign matter adhering to the filter; and a cleaning step of supplying a cleaning solution to the filter from the second end side after the purging step to remove the impurities and foreign matter adhering to the filter.

2. The filter cleaning method according to claim 1, further comprising a reversal step of reversing the first end and the second end of the filter between the purging step and the cleaning step.

3. A method for cleaning a filter according to claim 1 or 2, further comprising: a drying step of drying the filter by supplying gas to the filter after the cleaning step; and a particle measuring step of supplying gas to the filter from the first end side after the drying step and measuring the particles contained in the gas that has passed through the filter.

4. A method for cleaning a filter according to claim 1 or 2, further comprising: a drying step of drying the filter by supplying gas to the filter after the cleaning step; and a pressure measuring step of supplying gas to the filter from the first end after the drying step, and measuring the pressure of the gas at the first end of the filter and the pressure of the gas at the second end of the filter.

5. A method for cleaning a filter according to claim 1 or 2, further comprising a storage step of housing the filter in a housing after the purging step, wherein a cleaning solution is supplied to the filter housed in the housing in the cleaning step.

6. The filter cleaning method according to claim 5, further comprising a drying step of drying the filter housed in the housing by supplying gas to the filter after the cleaning step.

7. A filter cleaning device for removing impurities mixed in a raw material gas for polysilicon deposition and foreign matter adhering to the filter after polysilicon deposition from a filter having a first closed end, a second open end opposite to the first end, and a filter surface extending between the first end and the second end, the device comprising: a gas supply unit capable of removing the foreign matter adhering to the filter by supplying gas to the filter from the first end side and purging the inside of the filter via the filter surface; and a cleaning liquid supply unit capable of removing the impurities and foreign matter adhering to the filter by supplying cleaning liquid to the filter from the second end side.

8. The filter cleaning device according to claim 7, further comprising a reversal mechanism for reversing the first end and the second end of the filter.

9. The filter cleaning device according to claim 7, further comprising: a clamping portion for clamping the filter; and a transport portion for transporting the filter by moving the clamping portion while it is clamping the filter, wherein the clamping portion has a tip portion that makes point contact with the filter while it is clamping the filter.

10. The filter cleaning apparatus according to claim 7, further comprising: a measuring unit that, when gas is supplied to the filter, measures at least one of the following: measuring particles contained in the gas that has passed through the filter; measuring the pressure of the gas at the first end of the filter; and measuring the pressure of the gas at the second end of the filter; a conveying unit that conveys the filter from a cleaning position where the filter is cleaned by the cleaning liquid supply unit to a measuring position where the measurement is performed by the measuring unit; and a discharge unit that, based on the results of the measurement by the measuring unit, distributes the discharge destinations of a plurality of filters to a first discharge position and a second discharge position different from the first discharge position.

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