JP5888820B2 - Substrate processing apparatus, cleaning method, and semiconductor device manufacturing method - Google Patents

Description

  The present invention relates to a substrate processing apparatus that performs a film forming process on a substrate.

  As an example of the substrate processing apparatus, there is a semiconductor manufacturing apparatus. Further, as an example of the semiconductor manufacturing apparatus, a vertical ALD (Atomic Layer Deposition) apparatus is known. This vertical ALD apparatus has a vertically elongated buffer chamber near a wall surface inside a reaction tube for processing a substrate, and a discharge electrode and a gas nozzle covered with two dielectric tubes inside. Then, a high frequency power generated by an oscillator is applied to the end of the discharge electrode to generate plasma between the discharge electrodes in the buffer chamber, and a reactive gas supplied from the gas nozzle is excited by the plasma to provide a gas provided on the buffer chamber wall. The structure is such that a supply hole supplies the film to be processed in the reaction chamber (for example, Patent Document 1).

Japanese Patent No. 3947126

In the film forming process using the above apparatus, a film is also formed on other portions other than the substrate surface, such as the inner wall of the reaction tube. The films in these other parts are accumulated differently from the substrate, and the film thickness gradually increases. For this reason, cracks occur when the film thickness exceeds a certain film thickness, and when the film thickness is further increased, film peeling occurs, causing contamination of foreign matter. For this reason, after forming the film to a certain cumulative film thickness, the film formed on the inner wall of the reaction tube or the like is removed using, for example, NF ₃ or F ₂ .

  However, when a reaction tube having a complicated shape is used in the conventional method, for example, a film such as a back side of a nozzle to which a gas is supplied or a portion deviating from a direction from the nozzle toward the exhaust pipe cannot be removed or is difficult to remove. Site was present. If film residue occurs in such a part, these films accumulate and cause contamination of foreign matter. Therefore, the film must be removed by a method other than cleaning using gas, and the reaction tube Cleaning with hydrofluoric acid accompanied by removal and attachment would be performed, leading to a reduction in the operating rate of the apparatus.

  An object of the present invention is to provide a substrate processing apparatus capable of suppressing contamination of foreign substances in a reaction tube and preventing a reduction in apparatus operation rate.

  In order to achieve the above object, the present invention is characterized by a reaction tube that accommodates a substrate, first and second nozzles that supply gas into the reaction tube, and a cleaning gas supply system that supplies a cleaning gas. An inert gas supply system that supplies an inert gas, an exhaust system that exhausts the atmosphere in the reaction tube, a control system that controls the cleaning gas supply system, the inert gas supply system, and the exhaust system The control system controls the cleaning gas supply system and the inert gas supply system to supply the inert gas and the cleaning gas into the reaction tube via the first nozzle, and the inert gas A first step of controlling a gas supply system to supply an inert gas into the reaction tube via the second nozzle, and controlling an exhaust system to control a pressure in the reaction tube; In the substrate processing apparatus characterized a second step of stopping the supply of the inert gas through the second nozzle to control the inert gas supply system, to make repeated.

  ADVANTAGE OF THE INVENTION According to this invention, the substrate processing apparatus which can suppress the foreign material contamination in a reaction tube and can prevent the fall of an apparatus operating rate can be provided.

It is a perspective perspective view which shows the schematic structure of the substrate processing apparatus used suitably in one Embodiment of this invention. It is a schematic block diagram of an example of the processing furnace suitably used in one embodiment of the present invention and the members accompanying it, and is a view showing the processing furnace part in particular in a longitudinal section. It is the sectional view on the AA line of the processing furnace shown in FIG. 2 used suitably in one Embodiment of this invention. It is a figure which shows the flowchart explaining the film-forming process used suitably by one Embodiment of this invention. It is a figure which shows the sequence in the film-forming process used suitably in one Embodiment of this invention. It is a figure which shows the temperature setting according to zone of the heater used suitably in one Embodiment of this invention. FIG. 3 is a diagram showing a sequence in a cleaning process used in the first embodiment of the present invention. FIG. 8 is a diagram showing a relationship between a wafer mounting position and an etching rate on a cumulative wafer in the sequence shown in FIG. 7 used in the first embodiment of the present invention. It is a figure which shows the mode of the film thickness which implemented cleaning based on the result of FIG. 8 used for the 1st Example of this invention, and remained on the plate-shaped member. It is a figure which shows the sequence in the cleaning process used for the 2nd Example of this invention. It is a figure which shows the relationship between the mounting position of a wafer in the sequence shown in FIG. 10 used for the 2nd Example of this invention, and the etching rate on a cumulative wafer. It is a figure which shows the mode of the film thickness which implemented cleaning based on the result of FIG. 11 used for the 2nd Example of this invention, and remained on the plate-shaped member. It is a cross-sectional view which shows the mode of the inside of the processing furnace used suitably in one Embodiment of this invention. It is a figure which shows the sequence in the cleaning process used for the 3rd Example of this invention. It is a figure which shows the relationship between the mounting position of a wafer in the sequence shown in FIG. 14 used for the 3rd Example of this invention, and the etching rate on a cumulative wafer. It is a figure which shows the mode of the film thickness which implemented cleaning based on the result of FIG. 15 used for the 3rd Example of this invention, and remained on the plate-shaped member. It is a conceptual diagram which shows the mode in the reaction tube used suitably in one Embodiment of this invention. It is a figure which shows the sequence in the cleaning process used for the 4th Example of this invention. It is a figure which shows the relationship between the mounting position of a wafer in the sequence shown in FIG. 18 used for the 4th Example of this invention, and the etching rate on a cumulative wafer. It is a figure which shows the mode of the film thickness which implemented cleaning based on the result of FIG. 19 used for the 4th Example of this invention, and remained on the plate-shaped member.

  First, a configuration example of a substrate processing apparatus according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective perspective view of a substrate processing apparatus 101 according to the present embodiment. FIG. 2 is a side sectional view of the processing furnace 202 according to this embodiment. FIG. 3 is a top cross-sectional view of the processing furnace 202 according to the present embodiment, and the processing furnace 202 portion is shown by a cross-sectional view along the line AA in FIG.

(Configuration of substrate processing equipment)
As shown in FIG. 1, the substrate processing apparatus 101 according to the present embodiment includes a housing 111. In order to transport a wafer (substrate) 200 made of silicon or the like into and out of the casing 111, a cassette 110 as a wafer carrier (substrate storage container) that stores a plurality of wafers 200 is used. A cassette stage (substrate storage container delivery table) 114 is provided in front of the housing 111 (on the right side in the drawing). The cassette 110 is placed on the cassette stage 114 by an in-process transfer device (not shown), and is carried out of the casing 111 from the cassette stage 114.

  The cassette 110 is placed on the cassette stage 114 so that the wafer 200 in the cassette 110 is in a vertical posture and the wafer loading / unloading port of the cassette 110 faces upward by the in-process transfer device. The cassette stage 114 rotates the cassette 110 90 degrees in the vertical direction toward the rear of the casing 111 to bring the wafer 200 in the cassette 110 into a horizontal posture, and the wafer loading / unloading port of the cassette 110 is placed behind the casing 111. It is configured to be able to face.

  A cassette shelf (substrate storage container mounting shelf) 105 is installed at a substantially central portion in the front-rear direction in the housing 111. The cassette shelf 105 is configured to store a plurality of cassettes 110 in a plurality of rows and a plurality of rows. The cassette shelf 105 is provided with a transfer shelf 123 in which a cassette 110 to be transferred by a wafer transfer mechanism 125 described later is stored. Further, a preliminary cassette shelf 107 is provided above the cassette stage 114, and is configured to store the cassette 110 in a preliminary manner.

  A cassette transfer device (substrate container transfer device) 118 is provided between the cassette stage 114 and the cassette shelf 105. The cassette transport device 118 includes a cassette elevator (substrate storage container lifting mechanism) 118a that can be moved up and down while holding the cassette 110, and a cassette transport mechanism (substrate storage container transport mechanism) as a transport mechanism that can move horizontally while holding the cassette 110. 118b. The cassette 110 is transported between the cassette stage 114, the cassette shelf 105, the spare cassette shelf 107, and the transfer shelf 123 by the cooperative operation of the cassette elevator 118a and the cassette transport mechanism 118b.

  A wafer transfer mechanism (substrate transfer mechanism) 125 is provided behind the cassette shelf 105. The wafer transfer mechanism 125 includes a wafer transfer device (substrate transfer device) 125a that can rotate or linearly move the wafer 200 in the horizontal direction, and a wafer transfer device elevator (substrate transfer device) that moves the wafer transfer device 125a up and down. Elevating mechanism) 125b. The wafer transfer device 125a includes a tweezer (substrate transfer jig) 125c that holds the wafer 200 in a horizontal posture. The wafer 200 is picked up from the cassette 110 on the transfer shelf 123 by the cooperative operation of the wafer transfer device 125a and the wafer transfer device elevator 125b, and is loaded into the boat (substrate holder) 217 described later (charging). Or the wafer 200 is unloaded (discharged) from the boat 217 and stored in the cassette 110 on the transfer shelf 123.

  A processing furnace 202 is provided above the rear portion of the casing 111. An opening (furnace port) is provided at the lower end of the processing furnace 202, and the opening is opened and closed by a furnace port shutter (furnace port opening / closing mechanism) 147. The configuration of the processing furnace 202 will be described later.

  Below the processing furnace 202, a boat elevator (substrate holder lifting mechanism) 115 is provided as a lifting mechanism that lifts and lowers the boat 217 and transports the boat 217 into and out of the processing furnace 202. The elevator 128 of the boat elevator 115 is provided with an arm 128 as a connecting tool. On the arm 128, a disc-shaped seal cap 219 as a lid that supports the boat 217 vertically and hermetically closes the lower end of the processing furnace 202 when the boat 217 is raised by the boat elevator 115 is in a horizontal posture. Is provided.

  The boat 217 includes a plurality of holding members, and a plurality of (for example, about 50 to 150) wafers 200 are aligned in the vertical direction in a horizontal posture and in a state where the centers thereof are aligned in multiple stages. Configured to hold. The detailed configuration of the boat 217 will be described later.

  Above the cassette shelf 105, a clean unit 134a having a supply fan and a dustproof filter is provided. The clean unit 134a is configured to circulate clean air, which is a cleaned atmosphere, inside the casing 111.

  In addition, a clean unit (not shown) provided with a supply fan and a dustproof filter so as to supply clean air to the left end portion of the housing 111 opposite to the wafer transfer device elevator 125b and the boat elevator 115 side. Is installed. Clean air blown out from the clean unit (not shown) is configured to be sucked into an exhaust device (not shown) and exhausted to the outside of the casing 111 after circulating around the wafer transfer device 125a and the boat 217. ing.

  Next, the operation of the substrate processing apparatus 101 according to the present embodiment will be described.

  First, the cassette 110 is placed on the cassette stage 114 by an in-process transfer device (not shown) so that the wafer 200 is in a vertical posture and the wafer loading / unloading port of the cassette 110 faces upward. Thereafter, the cassette 110 is rotated 90 ° in the vertical direction toward the rear of the casing 111 by the cassette stage 114. As a result, the wafer 200 in the cassette 110 assumes a horizontal posture, and the wafer loading / unloading port of the cassette 110 faces rearward in the housing 111.

  The cassette 110 is automatically transported to the designated shelf position of the cassette shelf 105 or the spare cassette shelf 107 by the cassette transporting device 118, delivered, temporarily stored, and then stored in the cassette shelf 105 or the spare cassette shelf. The sample is transferred from 107 to the transfer shelf 123 or directly transferred to the transfer shelf 123.

  When the cassette 110 is transferred to the transfer shelf 123, the wafer 200 is picked up from the cassette 110 through the wafer loading / unloading port by the tweezer 125c of the wafer transfer device 125a, and the wafer transfer device 125a and the wafer transfer device elevator 125b are picked up. Are loaded (charged) into the boat 217 behind the transfer chamber 124. The wafer transfer mechanism 125 that has transferred the wafer 200 to the boat 217 returns to the cassette 110 and loads the next wafer 200 into the boat 217.

When a predetermined number of wafers 200 are loaded into the boat 217, the lower end of the processing furnace 202 closed by the furnace port shutter 147 is opened by the furnace port shutter 147. Subsequently, when the seal cap 219 is raised by the boat elevator 115, the boat 217 holding the wafer 200 group is loaded into the processing furnace 202. After loading, arbitrary processing is performed on the wafer 200 in the processing furnace 202.
Such processing will be described later. After the processing, the wafer 200 and the cassette 110 are discharged to the outside of the casing 111 by a procedure reverse to the above procedure.

  FIG. 2 is a schematic configuration diagram of a vertical processing furnace of the substrate processing apparatus in the present embodiment, showing the processing furnace 202 portion in a vertical cross section, and FIG. 3 is an outline of the vertical processing furnace of the substrate processing apparatus in the present embodiment. It is a block diagram and the process furnace 202 part is shown with a cross section.

  As shown in FIG. 2, the processing furnace 202 has a heater 207 as a heating means (heating mechanism). The heater 207 has a cylindrical shape and is vertically installed by being supported by a heater base (not shown) as a holding plate. A reaction tube 203 that constitutes a reaction vessel (processing vessel) concentrically with the heater 207 is provided inside the heater 207.

  Below the reaction tube 203, a seal cap 219 is provided as a furnace opening lid capable of airtightly closing the lower end opening of the reaction tube 203. The seal cap 219 is brought into contact with the lower end of the reaction tube 203 from the lower side in the vertical direction. The seal cap 219 is made of a metal such as stainless steel and has a disk shape. An O-ring 220 is provided on the upper surface of the seal cap 219 as a seal member that contacts the lower end of the reaction tube 203. A rotation mechanism 267 for rotating the boat is provided on the side of the seal cap 219 opposite to the processing chamber 201. A rotation shaft 255 of the rotation mechanism 267 passes through the seal cap and is connected to a boat 217 described later, and is configured to rotate the wafer 200 by rotating the boat 217. The seal cap 219 is configured to be moved up and down in the vertical direction by a boat elevator 115 as an elevating mechanism provided outside the reaction tube 203, so that the boat 217 can be carried into and out of the processing chamber 201. It is possible.

  A boat 217 as a substrate holding means (support) is erected on the seal cap 219 via a quartz cap 218 as a heat insulating member. The quartz cap 218 is made of a heat-resistant material such as quartz or silicon carbide, and functions as a heat insulating portion and serves as a holding body that holds the boat. The boat 217 is made of a heat-resistant material such as quartz or silicon carbide, and is configured to support a plurality of wafers 200 in a horizontal posture and in a state where their centers are aligned with each other and supported in multiple stages in the tube axis direction. Yes.

  A first nozzle 249 a and a second nozzle 249 b are provided in the processing chamber 201 and below the reaction tube 203 so as to penetrate the reaction tube 203. A first gas supply pipe 232a is connected to the first nozzle 249a, and a second gas supply pipe 232b is connected to the second nozzle 249b.

  A mass flow controller (MFC) 241a which is a flow rate controller (flow rate control unit), valves 243a and 247a which are on / off valves, a gas reservoir 248 and a valve 251a which is an on / off valve are sequentially provided in the first gas supply pipe 232a from the upstream direction. Is provided. The gas reservoir 248 is constituted by, for example, a gas tank or a spiral pipe having a larger gas capacity than a normal pipe. Then, by opening or closing the valve 247a or the valve 251a, DCS gas as a first processing gas to be described later is stored in the gas reservoir 248 via the first gas supply pipe 232a, or the stored DCS gas is stored in the processing chamber 201. It can be supplied inside. An inert gas supply pipe 232c is connected to the first gas supply pipe 232a. The inert gas supply pipe 232c is provided with a mass flow controller 241c that is a flow rate controller (flow rate control unit) and a valve 243c that is an on-off valve in order from the upstream direction. The first nozzle 249a is connected to the tip of the first gas supply pipe 232a. The first nozzle 249a rises in the arc-shaped space between the inner wall of the reaction tube 203 and the wafer 200 so as to rise upward in the stacking direction of the wafer 200 along the upper portion from the lower portion of the inner wall of the reaction tube 203. Is provided. The first nozzle 249a is configured as an L-shaped long nozzle. A gas supply hole 250a for supplying gas is provided on the side surface of the first nozzle 249a. The gas supply hole 250 a is opened to face the center of the reaction tube 203. A plurality of gas supply holes 250a are provided from the bottom to the top of the reaction tube 203, each having the same opening area, and further provided at the same opening pitch. A first gas supply system is mainly configured by the first gas supply pipe 232a, the mass flow controller 241a, the valves 243a and 247a, the gas reservoir 248, the valve 251a, and the first nozzle 249a. In addition, a first inert gas supply system is mainly configured by the inert gas supply pipe 232c, the mass flow controller 241c, and the valve 243c.

  A cleaning gas supply pipe 252 is connected to the downstream side of the valve 251a of the first gas supply pipe 232a. The cleaning gas supply pipe 252 is connected to a first cleaning gas supply pipe 252a and a second cleaning gas supply pipe 252b. The first cleaning gas supply pipe 252a is provided with a mass flow controller 253a that is a flow rate controller (flow rate control unit), a valve 254a that is an on-off valve, and a valve 256a that is an on-off valve in order from the upstream direction. . The second cleaning gas supply pipe 252b is provided with a mass flow controller 253b as a flow rate controller (flow rate control unit), a valve 254b as an on-off valve, and a valve 256b as an on-off valve in order from the upstream direction. . A cleaning gas supply system is mainly constituted by the first cleaning gas supply pipe 252a, the mass flow controller 253a, the valves 254a and 256a, the second cleaning gas supply pipe 252b, the mass flow controller 253b, the valves 254b and 256b, and the cleaning gas supply pipe 252. Is configured.

  The second gas supply pipe 232b is provided with a mass flow controller (MFC) 241b that is a flow rate controller (flow rate control unit) and valves 243b and 247b that are on-off valves in order from the upstream direction. Further, an inert gas supply pipe 232d is connected to the downstream side of the valve 243b of the second gas supply pipe 232b. The inert gas supply pipe 232d is provided with a mass flow controller 241d that is a flow rate controller (flow rate control unit) and a valve 243d that is an on-off valve in order from the upstream direction. The second nozzle 249b is connected to the tip of the second gas supply pipe 232b. The second nozzle 249b is provided in a buffer chamber 237 that is a gas dispersion space.

  The buffer chamber is provided in a circular arc space between the inner wall of the reaction tube 203 and the wafer 200 in a portion extending from the lower portion to the upper portion of the inner wall of the reaction tube 203 along the loading direction of the wafer 200. A gas supply hole 250 c for supplying a gas is provided at the end of the wall of the buffer chamber 237 adjacent to the wafer 200. The gas supply hole 250 c is opened to face the center of the reaction tube 203. A plurality of gas supply holes 250c are provided from the lower part to the upper part of the reaction tube 203, each having the same opening area, and further provided at the same opening pitch.

  The second nozzle 249b is located at the end of the buffer chamber 237 opposite to the end where the gas supply hole 250c is provided, and extends upward from the bottom of the inner wall of the reaction tube 203 in the stacking direction of the wafer 200. To stand up. The second nozzle 249b is configured as an L-shaped long nozzle. A gas supply hole 250b for supplying gas is provided on the side surface of the second nozzle 249b. The gas supply hole 250 b is opened to face the center of the buffer chamber 237. A plurality of gas supply holes 250 b are provided from the lower part to the upper part of the reaction tube 203, similarly to the gas supply holes 250 c of the buffer chamber 237. Each of the plurality of gas supply holes 250b has the same opening area from the upstream side (lower part) to the downstream side (upper part) when the differential pressure in the buffer chamber 237 and the processing chamber 201 is small. However, when the differential pressure is large, the opening area is increased or the opening pitch is decreased from the upstream side toward the downstream side.

  In this embodiment, by adjusting the opening area and opening pitch of each gas supply hole 250b from the upstream side to the downstream side as described above, first, there is a difference in flow velocity from each of the gas supply holes 250b. The gas having the same flow rate is ejected. Then, the gas ejected from each of the gas supply holes 250b is once introduced into the buffer chamber 237, and the difference in gas flow velocity is made uniform in the buffer chamber 237.

  That is, the gas ejected into the buffer chamber 237 from each gas supply hole 250b of the second nozzle 249b is reduced in the particle velocity of each gas in the buffer chamber 237 and then processed from the gas supply hole 250c in the buffer chamber 237. It spouts into 201. Thus, the gas ejected from the gas supply holes 250b into the buffer chamber 237 becomes a gas having a uniform flow rate and flow velocity when ejected from the gas supply holes 250c into the processing chamber 201.

  A second gas supply system is mainly configured by the second gas supply pipe 232b, the mass flow controller 241b, the valves 243b and 247b, the second nozzle 249b, and the buffer chamber 237. In addition, a second inert gas supply system is mainly configured by the inert gas supply pipe 232d, the mass flow controller 241d, and the valve 243d.

From the first gas supply pipe 232a, for example, a silicon source gas, that is, a gas containing silicon (Si) as a first element (silicon-containing gas) is used as the first processing gas, and the mass flow controller 241a, valves 243a and 247a. The gas is supplied into the processing chamber 201 through the gas reservoir 248, the valve 251a, and the first nozzle 249a. As the silicon-containing gas, for example, dichlorosilane (SiH ₂ Cl ₂ , DCS) gas, hexachlorodisilane (Si ₂ Cl ₆ , DCS) gas, or the like can be used. Note that the first processing gas may be any of solid, liquid, and gas at normal temperature and pressure, but will be described as a gas here. When the first processing gas is liquid at normal temperature and pressure, a vaporizer (not shown) is provided.

From the second gas supply pipe 232b, for example, a gas containing nitrogen (N) as the second element (nitrogen-containing gas) is used as a second processing gas for reforming the raw material gas, such as a mass flow controller 241b, valves 243b, 247b. The second nozzle 249 b and the buffer chamber 237 are supplied into the processing chamber 201. As the nitrogen-containing gas, for example, ammonia (NH ₃ ) gas can be used.

From the inert gas supply pipes 232c and 232d, for example, nitrogen (N ₂ ) gas as an inert gas flows through the mass flow controller 241c, the valve 243c, the first gas supply pipe 232a, and the first nozzle 249a, respectively. The gas is supplied into the processing chamber 201 through the controller 241d, the valve 243d, the second gas supply pipe 232b, the second nozzle 249b, and the buffer chamber 237.

From the first cleaning gas supply pipe 252a, for example, fluorine (F ₂ ) gas as a cleaning gas enters the processing chamber 201 through the mass flow controller 253a, valves 254a, 256a, the cleaning gas supply pipe 252 and the first nozzle 249a. To be supplied.
From the second cleaning gas supply pipe 252b, for example, nitrogen trifluoride (NF ₃ ) gas is used as a cleaning gas, such as a mass flow controller 253b, valves 254b, 256b, a cleaning gas supply pipe 252, a second nozzle 249b, and a buffer chamber 237. Is supplied into the processing chamber 201.

  For example, when each of the gases as described above is caused to flow from each gas supply pipe, the first gas supply system forms a raw material gas supply system, that is, a silicon-containing gas supply system (silane-based gas supply system). The second gas supply system constitutes a reformed gas supply system, that is, a nitrogen-containing gas supply system.

  In the buffer chamber 237, as shown in FIGS. 2 and 3, a first rod-shaped electrode 269 which is a first electrode having an elongated structure and a second rod-shaped electrode 270 which is a second electrode are provided in a reaction tube. The wafer 200 is disposed along the stacking direction of the wafer 200 from the lower part to the upper part. The first rod-shaped electrode 269 and the second rod-shaped electrode 270 are provided in parallel with the second nozzle 249b, and are respectively covered with an electrode protection tube 275 that is a protection tube that protects each electrode from the top to the bottom. Protected by Either the first rod-shaped electrode 269 or the second rod-shaped electrode 270 is connected to the high-frequency power source 273 via the matching unit 272, and the other is connected to the ground as the reference potential. As a result, plasma is generated in the plasma generation region 224 between the first rod-shaped electrode 269 and the second rod-shaped electrode 270. The first rod-shaped electrode 269, the second rod-shaped electrode 270, the electrode protection tube 275, the matching unit 272, and the high-frequency power source 273 mainly constitute a plasma source as a plasma generator (plasma generating unit). The plasma source functions as an activation mechanism that activates a gas with plasma as will be described later.

  The electrode protection tube 275 has a structure in which each of the first rod-shaped electrode 269 and the second rod-shaped electrode 270 can be inserted into the buffer chamber 237 while being isolated from the atmosphere of the buffer chamber 237. Here, if the inside of the electrode protection tube 275 has the same atmosphere as the outside air (atmosphere), the first rod-shaped electrode 269 and the second rod-shaped electrode 270 inserted into the electrode protection tube 275 are oxidized by heat from the heater 207. Will be. Therefore, the inside of the electrode protection tube 275 is filled or purged with an inert gas such as nitrogen to suppress the oxygen concentration sufficiently low to prevent oxidation of the first rod-shaped electrode 269 or the second rod-shaped electrode 270. An active gas purge mechanism (not shown) is provided.

  The reaction tube 203 is provided with an exhaust pipe 231 for exhausting the atmosphere in the processing chamber 201. The exhaust pipe 231 is evacuated via a pressure sensor 245 as a pressure detector (pressure detection unit) for detecting the pressure in the processing chamber 201 and an APC (Auto Pressure Controller) valve 244 as a pressure regulator (pressure adjustment unit). A vacuum pump as an exhaust device is connected, and the processing chamber 201 can be evacuated so that the pressure in the processing chamber 201 becomes a predetermined pressure (degree of vacuum). Note that the APC valve 244 is an open / close valve that can open and close the valve to evacuate / stop the evacuation in the processing chamber 201 and further adjust the valve opening to adjust the pressure. An exhaust system is mainly configured by the exhaust pipe 231, the APC valve 244, the vacuum pump 246, and the pressure sensor 245.

  A temperature sensor 263 as a temperature detector is installed in the reaction tube 203, and the temperature in the processing chamber 201 is adjusted by adjusting the power supply to the heater 207 based on the temperature information detected by the temperature sensor 263. It is configured to have a desired temperature distribution. The temperature sensor 263 is configured in an L shape similarly to the nozzles 249 a and 249 b, and is provided along the inner wall of the reaction tube 203.

  In the reaction tube 203, quartz plate-like members 266a and 266b for confirming a removal state of a film attached in the reaction tube 203 after supplying a cleaning gas, which will be described later, are provided. The plate-like members 266 a and 266 b are provided in a state extending along the stacking direction of the wafer 200 along the upper part from the lower part of the inner wall of the reaction tube 203. For example, the plate-shaped member 266a is a wall surface in the reaction tube 203 and is disposed at a position facing the gas supply hole 250a of the first nozzle 249a, and the plate-shaped member 266b is a wall surface in the reaction tube 203. It arrange | positions in the position adjacent to the 1st nozzle 249a.

  The controller 121 which is a control unit (control means) includes mass flow controllers 241a, 241b, 241c, 241d, 253a and 253b, valves 243a, 243b, 243c, 243d, 247a, 247b, 251a, 254a, 254b, 256a and 256b, pressure The sensor 245, the APC valve 244, the vacuum pump 246, the heater 207, the temperature sensor 263, the boat rotation mechanism 267, the boat elevator 115, the high frequency power supply 273, the matching unit 272, and the like are connected. The controller 121 adjusts the flow rate of various gases by the mass flow controllers 241a, 241b, 241c, 241d, 253a and 253b, and opens and closes the valves 243a, 243b, 243c, 243d, 247a, 247b, 251a, 254a, 254b, 256a and 256b. , Opening / closing of APC valve 244 and pressure adjustment operation based on pressure sensor 245, temperature adjustment operation of heater 207 based on temperature sensor 263, control of vaporizer 500, start / stop of vacuum pump 246, adjustment of rotation speed of boat rotation mechanism 267 Control of operation, raising / lowering operation of the boat elevator 115, power supply control of the high frequency power supply 273, and impedance control by the matching unit 272 are performed.

  Next, a sequence example in which an insulating film is formed on a substrate will be described as one step of a semiconductor device (device) manufacturing process using the processing furnace of the substrate processing apparatus described above. In the following description, the operation of each part constituting the substrate processing apparatus is controlled by the controller 121.

  In a conventional CVD (Chemical Vapor Deposition) method or ALD (Atomic Layer Deposition) method, for example, in the case of a CVD method, a plurality of types of gases including a plurality of elements constituting a film to be formed are simultaneously supplied. In this case, a plurality of types of gases containing a plurality of elements constituting the film to be formed are alternately supplied. Then, a silicon nitride film (SiN film) or a silicon oxide film (SiO film) is formed by controlling supply conditions such as a gas supply flow rate, a gas supply time, and plasma power at the time of gas supply. In those techniques, for example, when forming a SiN film, the composition ratio of the film is N / Si≈1.33 which is a stoichiometric composition, and when forming a SiO film, for example, the composition ratio of the film is The supply conditions are controlled for the purpose of O / Si≈2, which is the stoichiometric composition.

  On the other hand, it is possible to control the supply conditions for the purpose of setting the composition ratio of the film to be formed to a predetermined composition ratio different from the stoichiometric composition. That is, the supply conditions are controlled for the purpose of making at least one element out of the plurality of elements constituting the film to be formed more excessive than the other elements with respect to the stoichiometric composition. It is also possible to perform film formation while controlling the ratio of a plurality of elements constituting the film to be formed as described above, that is, the composition ratio of the film. In the following, a sequence example for forming a film having a stoichiometric composition by alternately supplying a plurality of types of gases containing different types of elements will be described.

Here, silicon (Si) is used as the first element, nitrogen (N) is used as the second element, DCS gas that is a silicon-containing gas is included as the first processing gas including the first element, and the second element is included. An example in which an NH ₃ gas that is a nitrogen-containing gas is used as the second processing gas and an SiN film is formed as an insulating film on the substrate will be described with reference to FIGS. FIG. 4 is a flowchart for explaining a film forming process in the present embodiment, and FIG. 5 is a diagram showing a sequence in the film forming process in the present embodiment. In this example, a silicon-containing gas supply system (first element-containing gas supply system) is configured by the first gas supply system, and a nitrogen-containing gas supply system (second element-containing) is formed by the second gas supply system. Gas supply system) is configured.

  First, when a plurality of wafers 200 are loaded into the boat 217 (wafer charge), the boat 217 supporting the plurality of wafers 200 is lifted by the boat elevator 115 and processed as shown in FIG. It is carried into the chamber 201 (boat loading). In this state, the seal cap 219 seals the lower end of the reaction tube 203 via the O-ring 220.

The processing chamber 201 is evacuated by a vacuum pump 246 so that a desired pressure (degree of vacuum) is obtained. At this time, the pressure in the processing chamber 201 is measured by the pressure sensor 245, and the APC valve 244 is feedback-controlled based on the measured pressure (pressure adjustment). Further, the processing chamber 201 is heated by the heater 207 so as to have a desired temperature. At this time, the power supply to the heater 207 is feedback-controlled based on the temperature information detected by the temperature sensor 263 so that the inside of the processing chamber 201 has a desired temperature distribution (temperature adjustment). Subsequently, the wafer 200 is rotated by rotating the boat 217 by the rotation mechanism 267. Next, a film forming process for forming a SiN film by supplying DCS gas and NH ₃ gas into the processing chamber 201 is performed.

(Film formation process)
<Step 11>
In step 11, gas is first flowed (first step). By opening and closing the valves 243a and 247a or the valve 251a of the first gas supply pipe 232a, DCS gas is caused to flow into the first gas supply pipe 232a through the gas reservoir 248. The flow rate of the DCS gas that has flowed through the first gas supply pipe 232a is adjusted by the mass flow controller 241a. The DCS gas whose flow rate has been adjusted is exhausted from the gas exhaust pipe 231 while being supplied into the processing chamber 201 from the gas supply hole 250a of the first nozzle 249a. At this time, the valve 243c is opened at the same time, and an inert gas is caused to flow into the inert gas supply pipe 232c. As the inert gas, a group 18 element gas such as He gas, Ne gas, Ar gas or the like is suitable. However, since the temperature of the heater 207, that is, the temperature of the wafer 200 is set low, N ₂ gas is used. Also good. The flow rate of the N ₂ gas flowing through the inert gas supply pipe 232c is adjusted by the mass flow controller 241c. The N ₂ gas whose flow rate has been adjusted is exhausted from the gas exhaust pipe 231 while being supplied into the processing chamber 201 together with the DCS gas.

  At this time, the APC valve 244 is appropriately adjusted so that the pressure in the processing chamber 201 is, for example, in the range of 10 to 1000 Pa. The supply flow rate of DCS gas controlled by the mass flow controller 241a is, for example, a flow rate in the range of 100 to 5000 sccm. The time during which the DCS gas is exposed to the wafer 200, that is, the gas supply time (irradiation time) is, for example, a time within the range of 2 to 120 seconds. At this time, the temperature of the heater 207 is set to such a temperature that the temperature of the wafer 200 becomes a temperature within a range of 300 to 600 ° C., for example.

  By supplying the DCS gas, a first layer containing silicon as the first element is formed on the base film on the surface of the wafer 200. That is, a silicon layer (Si layer) as a silicon-containing layer of less than one atomic layer to several atomic layers is formed on the wafer 200 (on the base film). The silicon-containing layer may be a DCS chemical adsorption (surface adsorption) layer. Silicon is an element that becomes a solid by itself. Here, the silicon layer includes a continuous layer made of silicon, a discontinuous layer, and a thin film formed by overlapping these layers. A continuous layer made of silicon may be referred to as a thin film. The DCS chemical adsorption layer includes a continuous chemical adsorption layer of DCS molecules and a discontinuous chemical adsorption layer. When the thickness of the silicon-containing layer formed on the wafer 200 exceeds several atomic layers, the nitriding action in step 13 described later does not reach the entire silicon-containing layer. The minimum value of the silicon-containing layer that can be formed on the wafer 200 is less than one atomic layer. Therefore, the thickness of the silicon-containing layer is preferably less than one atomic layer to several atomic layers. In addition, by adjusting conditions such as the temperature of the wafer 200 and the pressure in the processing chamber 201, under the condition that the DCS gas is self-decomposed, silicon is deposited on the wafer 200, and a silicon layer is formed. Under the condition where the self-decomposition does not occur, the layer to be formed can be adjusted so that the chemical adsorption layer of DCS is formed by the chemical adsorption of DCS on the wafer 200. Note that the film formation rate can be increased when the silicon layer is formed on the wafer 200 as compared with the case where the chemical adsorption layer of DCS is formed on the wafer 200. In addition, a denser layer can be formed when the silicon layer is formed on the wafer 200 than when a DCS chemical adsorption layer is formed on the wafer 200.

<Step 12>
In step 12 (second step), after the silicon-containing layer is formed, the valve 243a is closed and the supply of DCS gas is stopped. At this time, the DCS after the APC valve 244 of the gas exhaust pipe 231 is kept open and the processing chamber 201 is evacuated by the vacuum pump 246 to contribute to the formation of unreacted or silicon-containing layer remaining in the processing chamber 201. The gas is removed from the processing chamber 201. At this time, the valves 243c, 247a and 251a are kept open, and the supply of N ₂ gas into the processing chamber 201 is maintained. This enhances the effect of removing unreacted or residual DCS gas remaining in the processing chamber 201 from the processing chamber 201. As the inert gas, a rare gas such as Ar gas, He gas, Ne gas, or Xe gas may be used in addition to N ₂ gas.

<Step 13>
In step 13, after removing the residual gas in the processing chamber 201, the valves 243b and 247b of the second gas supply pipe 232b are opened, and NH ₃ gas is caused to flow into the second gas supply pipe 232b (third step). ). The flow rate of the NH ₃ gas that has flowed through the second gas supply pipe 232b is adjusted by the mass flow controller 241b. The NH ₃ gas whose flow rate has been adjusted is supplied into the buffer chamber 237 from the gas supply hole 250b of the second nozzle 249b. At this time, NH ₃ gas supplied into the buffer chamber 237 is plasma-excited by applying high-frequency power from the high-frequency power source 273 via the matching unit 272 between the first rod-shaped electrode 269 and the second rod-shaped electrode 270. Then, the active species is exhausted from the gas exhaust pipe 231 while being supplied into the processing chamber 201 from the gas supply hole 250c. At the same time, the valve 243d is opened and N ₂ gas is allowed to flow into the inert gas supply pipe 232d. The N ₂ gas is exhausted from the gas exhaust pipe 231 while being supplied into the processing chamber 201 together with the NH ₃ gas.

When flowing NH ₃ gas as active species by plasma excitation, the APC valve 244 is appropriately adjusted to set the pressure in the processing chamber 201 to a pressure in the range of 10 to 100 Pa, for example. The supply flow rate of the NH ₃ gas controlled by the mass flow controller 241b is, for example, a flow rate in the range of 1000 to 10,000 sccm. The time during which the wafer 200 is exposed to the active species obtained by plasma excitation of NH ₃ gas, that is, the gas supply time (irradiation time) is, for example, a time within the range of 2 to 120 seconds. At this time, the temperature of the heater 207 is set to such a temperature that the temperature of the wafer 200 is in the range of 300 to 600 ° C., as in step 11. In addition, the high frequency power applied between the 1st rod-shaped electrode 269 and the 2nd rod-shaped electrode 270 from the high frequency power supply 273 is set so that it may become the electric power within the range of 50-1000W, for example. NH ₃ gas has a high reaction temperature, and it is difficult to react at the wafer temperature and the processing chamber pressure as described above. Therefore, the NH ₃ gas is made to flow after being activated by plasma excitation. Therefore, the temperature of the wafer 200 is as described above. The low temperature range set in (2) may be maintained. Note that, when the NH ₃ gas is supplied, plasma excitation is not performed, and the temperature of the heater 207 is appropriately adjusted to adjust the wafer 20.
The temperature of 0 is set to, for example, 600 ° C. or higher, and the APC valve 244 is appropriately adjusted so that the pressure in the processing chamber 201 is set to a pressure in the range of 50 to 3000 Pa, for example, so that the NH ₃ gas is non-plasma. Thermal activation is also possible. When NH ₃ gas is activated by heat and supplied, a soft reaction can be caused.

At this time, the gas flowing in the processing chamber 201 is activated species obtained by plasma-exciting NH ₃ gas, or NH ₃ gas that is thermally activated by increasing the pressure in the processing chamber 201. There is no DCS gas flowing in the processing chamber 201. Therefore, NH ₃ gas does not cause a gas phase reaction became active species, or activated NH ₃ gas, the silicon-containing layer as a first layer formed on the wafer 200 in step 11 React with some of the. As a result, the silicon-containing layer is nitrided and modified into a second layer containing silicon (first element) and nitrogen (second element), that is, a silicon nitride layer (SiN layer).

<Step 14>
In step 14 (fourth step), the valve 243b of the second gas supply pipe 232b is closed to stop the supply of NH ₃ gas. At this time, the APC valve 244 of the gas exhaust pipe 231 is kept open, the processing chamber 201 is evacuated by the vacuum pump 246, and the NH ₃ gas remaining in the processing chamber 201 and contributing to nitridation is removed. Excluded from the processing chamber 201. At this time, the valves 243d and 247b remain open, and the supply of N ₂ gas into the processing chamber 201 is maintained. This enhances the effect of removing NH ₃ gas remaining in the processing chamber 201 and remaining unreacted or contributed to nitridation from the processing chamber 201.

As the nitrogen-containing gas, in addition to a gas in which NH ₃ gas is excited by plasma or heat, a gas in which N ₂ gas, NF ₃ gas, N ₃ H ₈ gas or the like is excited by plasma or heat may be used. A gas obtained by diluting a gas with a rare gas such as Ar gas, He gas, Ne gas, or Xe gas may be excited with plasma or heat.

  By performing the above steps 11 to 14 as one cycle and performing this cycle at least once, a SiN film containing silicon (first element) and nitrogen (second element) having a predetermined thickness on the wafer 200 is formed. A film can be formed. The above cycle is preferably repeated a plurality of times.

When a film forming process for forming a SiN film having a predetermined thickness is performed, an inert gas such as N ₂ gas is exhausted while being supplied into the process chamber 201, whereby the inside of the process chamber 201 is purged with the inert gas. (Gas purge). Thereafter, the atmosphere in the processing chamber 201 is replaced with an inert gas (inert gas replacement), and the pressure in the processing chamber 201 is returned to normal pressure (return to atmospheric pressure).

  Thereafter, the seal cap 219 is lowered by the boat elevator 115, the lower end of the reaction tube 203 is opened, and the processed wafer 200 is supported by the boat 217 from the lower end of the reaction tube 203 to the outside of the reaction tube 203. Unload (boat unload). Thereafter, the processed wafer 200 is taken out from the boat 217 (wafer discharge).

Thereby, a SiN film (initial SiN film) can be formed on the surface of the wafer 200 using DCS gas and NH ₃ gas.

  By the way, when the above film forming steps are performed, the SiN film is also deposited on the inner wall of the reaction tube 203 or the like. When the thickness of the deposited film exceeds a certain value, film peeling occurs, which causes generation of foreign matter on the wafer 200.

Therefore, in the present embodiment, a cleaning step using F ₂ gas is performed before the thickness of the deposited film becomes peeled or when the predetermined number of cycles is reached. FIG. 6 is a diagram showing the temperature setting for each zone of the heater suitably used in one embodiment of the present invention. The temperature of the heater is set to 300 to 450 ° C., for example. At this time, the heater 207 is divided into five zones, U, CU, C, CL, and L zones, from the upper end. The temperature can be changed for each zone.

First, the temperatures of the U, CU, C, and CL zones from the upper end of the heater 207 are set to, for example, 300 ° C., and the L zone is set to 450 ° C. In this temperature setting, the lower part of the reaction tube 203 below the L zone is mainly cleaned.
Next, the temperature of the U, CU, C, and CL zones from the upper end of the heater 207 is set to 400 ° C., for example, and the L zone is set to 350 ° C. This mainly cleans the site such as the reaction tube 203 above the CL zone.
As described above, by changing the temperature setting, the lower part of the reaction tube, which is difficult to etch the film, is cleaned in the first stage, and the other parts are cleaned in the second stage, thereby performing uniform etching. be able to.

(Cleaning process)
[First embodiment]
FIG. 7 shows a sequence in the cleaning process used in the first embodiment.
The valves 243d and 247b are opened, and N ₂ gas is allowed to flow into the inert gas supply pipe 232d. Here, for example, the mass flow controller 241d is used to flow N ₂ gas at 8.0 slm. The N ₂ gas is supplied into the reaction tube 203 through the second gas supply pipe 232b, the second nozzle 249b, and the buffer chamber 237.
Further, the valves 254a and 256a are opened, and F ₂ gas is caused to flow into the first cleaning gas supply pipe 252a. Here, for example, the mass flow controller 253a is used to flow F ₂ gas at 2.0 slm. The F ₂ gas is supplied into the reaction tube 203 through the first cleaning gas supply pipe 252a, the cleaning gas supply pipe 252 and the first nozzle 249a.
Then, by controlling the inside of the furnace to 50 Torr with the APC valve 244, the SiN film formed as described above can be etched.

FIG. 8 shows the relationship between the mounting position of the wafer 200 and the etching rate on the accumulated wafer 200 in the above-described sequence used in the first embodiment.
Here, in the substrate processing apparatus 101, a total of five monitoring wafers 199 are set on the top and bottom of the wafer 200 and every 25 wafers in a configuration in which 100 wafers are processed in one batch. Of these five sheets, the uppermost area around the boat 217 is referred to as a top area (T), the middle area around the center is a center area (C), and the lowermost area around the bottom position is a bottom area (B). Furthermore, the heights of the plate-like members 266a and 266b having the same height as the monitoring wafer 199 in each region are designated as mon T, mon CT, mon C, mon CB, and mon B from the top. Further, the uppermost periphery of the quartz cap 218 as a heat insulating member is a heat insulating plate T, the middle periphery is a heat insulating plate C, and the lowermost periphery is a heat insulating plate B.

As shown in FIG. 8, it can be seen that the etching rate is slow in the top region which is the top of the boat 217. Further, when the plate-like members 266a and 266b in which films are accumulated as in the wafer 200 are cleaned based on the etching rate in the center region so as to etch all the accumulated films, FIG. 9 shows. As shown, it can be seen that both the plate-like members 266a and 266b have left films in mon T and mon CT located in the top region. This is because the flow rate is small and the internal pressure of the nozzle does not increase because the F ₂ gas flows through the gas supply hole 250a having a large number of holes, and the F ₂ gas is supplied to the top region. This is thought to be due to a decrease. In this state, the film remains in the top region even after the film is completely removed in the center region and the bottom region. Further, when the film in the top region is completely removed, the reaction tube 203 main body and the like are etched in the center region and the bottom region, and the structure is damaged.

[Second embodiment]
FIG. 10 shows a sequence in the cleaning process used in the second embodiment.
<Step 1>
The valves 243d and 247b are opened, and N ₂ gas is allowed to flow into the inert gas supply pipe 232d using a mass flow controller 241d through 0.3 slm, via the second gas supply pipe 232b, the second nozzle 249b, and the buffer chamber 237. , Supplied into the reaction tube 203.
Further, the valves 243c, 247a, and 251a are opened, and N ₂ gas is allowed to flow into the inert gas supply pipe 232c. Here, for example, N ₂ gas is allowed to flow at 8.0 slm using the mass flow controller 241c. The N ₂ gas is supplied into the reaction tube 203 through the first gas supply pipe 232a and the first nozzle 249a. Further, the valves 254a and 256a are opened, and F ₂ gas is caused to flow into the first cleaning gas supply pipe 252a. Here, for example, the mass flow controller 253a is used to flow F ₂ gas at 2.0 slm. The F ₂ gas is supplied into the reaction tube 203 through the first cleaning gas supply pipe 252a, the cleaning gas supply pipe 252 and the first nozzle 249a. In other words, the N ₂ and F ₂ gases are supplied into the processing chamber 201 through the first gas supply pipe 232a and the first nozzle 249a.
Then, the inside of the furnace is controlled to 50 Torr by the APC valve 244.
<Step 2>
The valves 243d and 247b are closed, and the supply of N ₂ gas from the second nozzle 249b and the buffer chamber 237 is stopped.
By repeating Step 1 and Step 2, F ₂ gas can be put into the buffer chamber 237, and the film attached to the nozzle can be removed by backflow or the like.

FIG. 11 shows the relationship between the mounting position of the wafer 200 and the etching rate on the accumulated wafer 200 in the above-described sequence used in the second embodiment.
As shown in FIG. 11, the etching rate in the top region can be increased and the difference in the etching rate at each position can be reduced as compared with the first embodiment. This is because the F ₂ gas flowed 2.0 slm and the N ₂ gas flow 8.0 slm to the first nozzle 249a, so the internal pressure of the nozzle increased and the supply of F ₂ gas to the top region increased. it is conceivable that. Further, when cleaning is performed on the plate-like members 266a and 266b on which the films are accumulated in the same manner as the wafer 200 so as to etch all the accumulated films based on the etching rate in the top region, as shown in FIG. As can be seen, all of the film on the plate-like member 266a could be etched, but in the plate-like member 266b, the film still remains in mon T, mon CT and mon C located in the top region. I understand that. This is because, as shown in FIG. 13, since a gas flow 301 is generated, it is considered that there is a region 302 in which the gas hardly flows in the vicinity of the gas supply hole 250a from which the cleaning gas comes out. Thereby, in the plate-like member 266b installed near the first nozzle 249a, it is considered that the etching rate is effectively slowed down and the film remains.

[Third embodiment]
FIG. 14 shows a sequence in the cleaning process used in the third embodiment.
<Step 1>
The valves 243c, 247a, and 251a are opened, and N ₂ gas is allowed to flow into the inert gas supply pipe 232c. Here, for example, N ₂ gas is allowed to flow at 8.0 slm using the mass flow controller 241c. The N ₂ gas is supplied into the reaction tube 203 through the first gas supply pipe 232a and the first nozzle 249a.
Further, the valves 254a and 256a are opened, and F ₂ gas is caused to flow into the first cleaning gas supply pipe 252a. Here, for example, the mass flow controller 253a is used to flow F ₂ gas at 2.0 slm. The F ₂ gas is supplied into the reaction tube 203 through the first cleaning gas supply pipe 252a, the cleaning gas supply pipe 252 and the first nozzle 249a. In other words, the N ₂ and F ₂ gases are supplied into the processing chamber 201 through the first gas supply pipe 232a and the first nozzle 249a.
Then, the inside of the furnace is controlled to 50 Torr by the APC valve 244 (for example, 60 seconds).
<Step 2>
The valves 243d and 247b are opened, and N ₂ gas is allowed to flow into the inert gas supply pipe 232d using a mass flow controller 241d through 0.3 slm, via the second gas supply pipe 232b, the second nozzle 249b, and the buffer chamber 237. Then, N ₂ gas is supplied into the reaction tube 203 (for example, 30 seconds).
<Step 3>
The valves 243c, 247a, 251a, 254a, 256a are closed to stop the supply of N ₂ gas and F ₂ gas from the first nozzle 249a, and the APC valve 244 is closed to flow the gas in the reaction tube 203 (For example, 90 seconds).
By repeating steps 1 to 3, the accumulated film can be etched.

FIG. 15 shows the relationship between the mounting position of the wafer 200 and the etching rate on the accumulated wafer 200 in the above-described sequence used in the third embodiment.
As shown in FIG. 15, the etching rate can be increased as a whole compared with the first and second embodiments described above. Based on the etching rate in the top region at this time, when the plate-like members 266a and 266b in which the films are accumulated in the same manner as the wafer 200 are cleaned so as to etch all the accumulated films, FIG. As shown in the figure, the mon CT can etch all the film even in the top region of the plate-like member 266b. However, it can be seen that the film still remains in mon T, which is the top of the top region. As shown in FIG. 17, in the center region and the bottom region, the gas that wraps around only reaches the nozzle 303, whereas in the top region, the gas that wraps around reaches the nozzle. Since it is divided into 303a and 303b that wraps around the dome portion at the top of the reaction tube 203, it is considered that the etching rate is effectively slowed down and the film remains.

[Fourth embodiment]
FIG. 18 shows a sequence in the cleaning process used in the fourth embodiment.
<Step 1>
The valves 243d and 247b are opened, and N ₂ gas is allowed to flow into the inert gas supply pipe 232d. Here, for example, N ₂ gas is supplied at 0.3 slm using the mass flow controller 241d. The N ₂ gas is supplied into the reaction tube 203 through the second gas supply pipe 232b, the second nozzle 249b, and the buffer chamber 237.
Further, the valves 243c, 247a, and 251a are opened, and N ₂ gas is allowed to flow into the inert gas supply pipe 232c. Here, for example, N ₂ gas is allowed to flow at 8.0 slm using the mass flow controller 241c. Further, the valves 254a and 256a are opened, and F ₂ gas is caused to flow into the first cleaning gas supply pipe 252a. Here, for example, the mass flow controller 253a is used to flow F ₂ gas at 2.0 slm. In other words, the N ₂ and F ₂ gases are supplied into the processing chamber 201 through the first gas supply pipe 232a and the first nozzle 249a.
Then, the inside of the furnace is controlled to 50 Torr by the APC valve 244.
<Step 2>
Next, the valves 243d and 247b are closed, and the supply of N ₂ gas from the second nozzle 249b and the buffer chamber 237 is stopped.
<Step 3>
Next, the valves 243d and 247b are opened, and N ₂ gas is caused to flow into the inert gas supply pipe 232d. Here, for example, the mass flow controller 241d is used to flow N ₂ gas at 0.5 slm. The N ₂ gas is supplied into the reaction tube 203 through the second gas supply pipe 232b, the second nozzle 249b, and the buffer chamber 237.
Further, the flow rate of N ₂ gas from the first nozzle 249a is set to 0.5 slm using the mass flow controller 241c.
Further, the valves 254a and 256a are closed to stop the supply of F ₂ gas, and the APC valve 244 is gradually opened to lower the pressure.
<Step 4>
The APC valve 244 is completely opened and the gas in the reaction tube 203 is exhausted.
By repeating steps 1 to 4, the accumulated film can be etched.

FIG. 19 shows the relationship between the mounting position of the wafer 200 and the etching rate on the accumulated wafer 200 in the above-described sequence used in the fourth embodiment.
Based on the etching rate in the top region at this time, when the plate-like members 266a and 266b in which the films are accumulated as in the wafer 200 are cleaned so as to etch all the accumulated films, FIG. As shown in the figure, it can be seen that in the plate-like member 266b, the film remains on the bottom B of the bottom region and the heat insulating plate T which is the region below the reaction tube 203. However, these regions can be removed by setting the cleaning temperature below the reaction tube. On the other hand, it can be seen that the accumulated film above the reaction tube 203 such as the top region can be removed almost uniformly. The reason why all the films could not be removed is thought to be because the etching rate of the films on the plate-like members 266a and 266b is slower than that on the wafer 200.

Therefore, by providing an elongated quartz plate-like member along the wafer stacking direction with respect to the quartz reaction tube, the removal state of the film by cleaning can be confirmed.
In addition, by using the above-described embodiment, it is possible to uniformly etch the accumulated film formed on a portion other than the substrate surface such as the inner wall of the reaction tube.

  According to the present invention, a film formed on a portion other than the substrate surface such as the inner wall of the reaction tube, particularly on the back side of the porous nozzle, where gas is difficult to flow around, or on the ceiling of the reaction tube where gas is difficult to reach is etched uniformly. be able to.

  In addition, this invention is applicable also to the film | membrane type | mold using the raw material which is liquid at normal temperature normal pressure irrespective of a film | membrane type | mold.

[Preferred embodiment of the present invention]
Hereinafter, preferred embodiments of the present invention will be additionally described.

(Appendix 1)
According to one aspect of the present invention, in the gas cleaning, the substrate processing apparatus that repeatedly performs the pressure control while supplying the cleaning gas and the step of stopping the supply of the cleaning gas and exhausting the cleaning gas. Is provided.
(Appendix 2)
According to another aspect of the present invention, in the gas cleaning, the substrate processing is performed by repeatedly performing the pressure control while supplying the cleaning gas and the step of stopping the supply of the cleaning gas and further completely stopping the exhaust. An apparatus is provided.
(Appendix 3)
According to another aspect of the present invention, in gas cleaning, the steps of pressure control while supplying the cleaning gas, the step of stopping the supply of the cleaning gas and further stopping the exhaust, and the exhaust of the cleaning gas are performed. There is provided a substrate processing apparatus that repeatedly performs the steps.

101 substrate processing apparatus 121 controller 200 wafer (substrate)
201 Processing chamber 202 Processing furnace 203 Reaction tube 207 Heater 217 Boat 218 Quartz cap (heat insulating plate)
231 Exhaust pipe 237 Buffer chamber 248 Gas reservoir 249 Nozzle 250 Gas supply hole 266 Plate member

Claims (14)

A reaction tube containing a substrate;
First and second nozzles for supplying gas into the reaction tube;
A cleaning gas supply system for supplying a cleaning gas;
An inert gas supply system for supplying an inert gas;
Controlling the cleaning gas supply system and the inert gas supply system to supply the cleaning gas into the reaction tube while supplying the inert gas into the reaction tube through the first nozzle; A first process of controlling an inert gas supply system to supply an inert gas into the reaction tube via the second nozzle, and supplying the inert gas and a cleaning gas via the first nozzle And a control unit configured to repeatedly perform the second process of stopping the supply of the inert gas through the second nozzle,
A substrate processing apparatus.   The controller further supplies an inert gas again into the reaction tube through the second nozzle after the second treatment, and stops supplying cleaning gas through the first nozzle. The substrate processing apparatus according to claim 1, wherein the third processing is performed, and the first to third processing is repeatedly performed.   The control unit further controls the cleaning gas supply system and the inert gas supply system so that the supply amount of the inert gas supplied through the first nozzle passes through the second nozzle. The substrate processing apparatus according to claim 1, wherein the substrate processing apparatus is configured to be controlled to be larger than a supply amount of the inert gas supplied. The reaction tube can accommodate a plurality of stacked substrates,
The first and second nozzles are erected along the stacking direction of the plurality of substrates, and a plurality of gas supply holes for ejecting gas into the reaction tube are opened along the stacking direction of the plurality of substrates. The substrate processing apparatus according to claim 1.   The substrate processing apparatus according to claim 4, wherein each of the plurality of gas supply holes has the same opening area.   6. The substrate processing apparatus according to claim 4, further comprising a plate-like member that is provided along a lower portion to an upper portion of an inner wall of the reaction tube and is made of the same material as the reaction tube. A cleaning gas is supplied into the reaction tube while supplying an inert gas into the reaction tube via a first nozzle that supplies a gas into the reaction tube, and a second nozzle that supplies a gas into the reaction tube. A first step of supplying an inert gas into the reaction tube;
A second step of stopping the supply of the inert gas through the second nozzle while supplying the inert gas and the cleaning gas through the first nozzle;
A cleaning method in which the inside of the reaction tube is cleaned repeatedly. After the second step, a third step of supplying the inert gas again into the reaction tube through the second nozzle and stopping the supply of the cleaning gas through the first nozzle;
Further comprising
The cleaning method according to claim 7, wherein the inside of the reaction tube is cleaned by repeating the first to third steps. A fourth step of exhausting the atmosphere in the reaction tube after the third step; and
The cleaning method according to claim 8, wherein the inside of the reaction tube is cleaned by repeating the first to fourth steps. A first step of supplying a cleaning gas into the reaction tube while supplying an inert gas into the reaction tube via a first nozzle for supplying a gas into the reaction tube;
A second step of supplying an inert gas into the reaction tube via a second nozzle for supplying gas into the reaction tube;
A third step of stopping the supply of the inert gas and the cleaning gas through the first nozzle and the exhaust of the atmosphere in the reaction tube while supplying the inert gas through the second nozzle;
A cleaning method in which the inside of the reaction tube is cleaned repeatedly. While supplying an inert gas into the reaction tube through a first nozzle that supplies gas into the reaction tube, a cleaning gas is supplied into the reaction tube through the first nozzle, and a gas is supplied into the reaction tube. A first step of supplying an inert gas into the reaction tube via a second nozzle;
A second step of stopping the supply of the inert gas through the second nozzle while supplying the inert gas and the cleaning gas through the first nozzle;
In a state of stopping the supply of the cleaning gas, supplies the inert gas prior Symbol reaction tube through the first nozzle, the reaction tube of the inert gas through the second nozzle A third step of supplying;
A fourth step of evacuating the atmosphere in the reaction tube;
A cleaning method in which the inside of the reaction tube is cleaned repeatedly.   12. The cleaning according to claim 7, wherein a supply amount of the inert gas supplied through the first nozzle is larger than a supply amount of the inert gas supplied through the second nozzle. Method.   The cleaning method according to claim 7, wherein a plate-like member made of the same material as the reaction tube is provided along the inner wall of the reaction tube to check the cleaning state. A film forming process for performing a film forming process on the substrate accommodated in the reaction tube in the substrate processing apparatus;
A step of cleaning the inside of the reaction tube by the cleaning method according to claim 7;
A method for manufacturing a semiconductor device comprising: