JP2012059997A - Semiconductor device manufacturing method and substrate processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device manufacturing method and a substrate processing apparatus which improve a deposition rate and film thickness uniformity of a thin film formed on a substrate by enhancing supply of material gasses to the substrate.SOLUTION: The semiconductor manufacturing method comprises: a step of depositing a thin film of a predetermined film thickness on a substrate by performing one or more cycles each including a step of supplying a material gas into a processing chamber in which the substrate is stored and exhausting the material gas through an exhaust duct, and a step of supplying a reaction gas different from the material gas into the processing chamber and exhausting the reaction gas through the exhaust duct. In the step of supplying the material gas, a valve provided on the exhaust duct is temporarily closed fully to temporarily block the exhaust duct immediately before supplying the material gas.

Description

  The present invention relates to a semiconductor device manufacturing method and a substrate processing apparatus including a step of forming a thin film on a substrate.

  As a process of manufacturing a semiconductor device (device), a source gas is supplied into a processing vessel containing a substrate and exhausted from an exhaust pipe, and a reactive gas different from the source gas is supplied into the processing vessel and an exhaust pipe. A substrate processing step of forming a thin film with a predetermined film thickness on the substrate may be performed by performing this cycle one or more times with the step of exhausting as one cycle.

  However, when the above-described substrate processing step is performed, the amount of source gas supplied to the substrate may be insufficient and the film formation rate may be reduced. In addition, the amount of source gas supplied to the substrate becomes non-uniform, and the film thickness uniformity of the thin film formed on the substrate may be reduced.

  An object of the present invention is to provide a method of manufacturing a semiconductor device and a substrate processing apparatus capable of promoting the supply of a source gas to the substrate and improving the film forming speed and film thickness uniformity of a thin film formed on the substrate. There is.

According to one aspect of the invention,
Supplying a source gas into a processing container containing a substrate and exhausting it from an exhaust pipe;
Supplying a reaction gas different from the source gas into the processing vessel and exhausting the exhaust gas from the exhaust pipe;
1 cycle, and performing this cycle one or more times to form a thin film with a predetermined thickness on the substrate,
In the step of supplying the source gas, a method of manufacturing a semiconductor device is provided in which the valve provided in the exhaust pipe is temporarily fully closed to temporarily close the exhaust pipe immediately before the source gas is supplied. Is done.

According to another aspect of the invention,
A processing container for accommodating and processing the substrate;
A raw material gas supply system for supplying a raw material gas into the processing vessel;
A reaction gas supply system for supplying a reaction gas different from the source gas into the processing vessel;
An exhaust pipe for exhausting the inside of the processing vessel;
A valve provided in the exhaust pipe;
An exhaust device connected to the exhaust pipe;
The process of supplying the raw material gas into the processing container containing the substrate and exhausting it from the exhaust pipe, and the process of supplying the reaction gas into the processing container and exhausting from the exhaust pipe are defined as one cycle. By performing the cycle one or more times, a process for forming a thin film with a predetermined thickness on the substrate is performed, and the valve is temporarily fully closed immediately before supplying the source gas into the processing container. A method of manufacturing a semiconductor device is provided that includes a control unit that controls the source gas supply system, the reaction gas supply system, the valve, and the exhaust device so as to temporarily close the exhaust pipe.

  According to the method for manufacturing a semiconductor device and the substrate processing apparatus according to the present invention, it is possible to promote the supply of the source gas to the substrate and to improve the film formation rate and the film thickness uniformity of the thin film formed on the substrate. .

It is a schematic block diagram of the vertical processing furnace of the substrate processing apparatus used suitably by this embodiment, and is a figure which shows a processing furnace part with a vertical cross section. It is a schematic block diagram of the vertical processing furnace of the substrate processing apparatus used suitably by this embodiment, and is a figure which shows a processing furnace part with the sectional view on the AA line of FIG. (A) is a schematic diagram which shows the opening / closing timing and gas supply timing of the APC valve concerning the 1st sequence of this embodiment, (b) is a schematic diagram which shows the opening / closing timing and gas supply timing of the conventional APC valve. It is. (A) is a schematic diagram which shows the timing of gas supply which concerns on the 2nd sequence of this embodiment, and the opening / closing state of an APC valve, (b) is a schematic diagram which shows the timing of conventional gas supply, and the opening / closing state of an APC valve. It is. (A) is a schematic diagram showing a pressure change in the processing chamber when the APC valve is fully closed immediately before supplying the HCD gas, and (b) is a processing chamber when supplying the HCD gas with the APC valve opened. It is a schematic diagram which shows the pressure change of. It is a graph which shows the film-forming speed | rate of the SiON film which concerns on the Example of this invention with the film-forming speed | rate of the SiON film which concerns on a comparative example. It is a graph which shows the pressure change in the process chamber which concerns on the Example of this invention with the pressure change in the process chamber which concerns on a comparative example.

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

(1) Configuration of Substrate Processing Apparatus FIG. 1 is a schematic configuration diagram of a vertical processing furnace of a substrate processing apparatus suitably used in the present embodiment, and shows a processing furnace 202 portion in a vertical section. FIG. 1 is a schematic configuration diagram of a vertical processing furnace suitably used in the present embodiment, and a processing furnace 202 portion is shown by a cross-sectional view along the line AA in FIG.

  As shown in FIG. 1, the processing furnace 202 includes 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. The heater 207 also functions as an activation mechanism that activates gas with heat, as will be described later.

Inside the heater 207, a reaction tube 203 constituting a reaction vessel (processing vessel) concentrically with the heater 207 is disposed. The reaction tube 203 is made of a heat-resistant material such as quartz (SiO ₂ ) or silicon carbide (SiC), and is formed in a cylindrical shape with the upper end closed and the lower end opened. A processing chamber 201 is formed in a hollow cylindrical portion of the reaction tube 203, and is configured to be able to accommodate wafers 200 as substrates in a state of being aligned in multiple stages in a horizontal posture and in a vertical direction by a boat 217 described later.

A first nozzle 249 a, a second nozzle 249 b, a third nozzle 249 c, and a fourth nozzle 249 d are provided below the reaction tube 203 in the processing chamber 201 so as to penetrate the reaction tube 203. The first nozzle 249a, the second nozzle 249b, the third nozzle 249c, and the fourth nozzle 249d include a first gas supply pipe 232a, a second gas supply pipe 232b, a third gas supply pipe 232c, and a fourth gas supply pipe 232d. , Each connected. Thus, the reaction tube 203 is provided with four nozzles 249a, 249b, 249c, and 249d and four gas supply tubes 232a, 232b, 232c, and 232d. Then, it is comprised so that four types of gas can be supplied.

  The first gas supply pipe 232a is provided with a mass flow controller (MFC) 241a that is a flow rate controller (flow rate control unit) and a valve 243a that is an on-off valve in order from the upstream direction. A first inert gas supply pipe 232e is connected to the downstream side of the valve 243a of the first gas supply pipe 232a. The first inert gas supply pipe 232e is provided with a mass flow controller 241e that is a flow rate controller (flow rate control unit) and a valve 243e that is an on-off valve in order from the upstream direction. The first nozzle 249a described above is connected to the tip of the first gas supply pipe 232a. The first nozzle 249a is provided in an arc-shaped space between the inner wall of the reaction tube 203 and the wafer 200 so as to rise upward from the lower portion of the inner wall of the reaction tube 203 in the stacking direction of the wafer 200. It has been. 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 valve 243a, and the first nozzle 249a. Further, a first inert gas supply system is mainly configured by the first inert gas supply pipe 232e, the mass flow controller 241e, and the valve 243e.

  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 a valve 243b that is an on-off valve in order from the upstream direction. Further, a second inert gas supply pipe 232f is connected to the downstream side of the valve 243b of the second gas supply pipe 232b. The second inert gas supply pipe 232f is provided with a mass flow controller 241f as a flow rate controller (flow rate control unit) and a valve 243f as 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 249 b is provided in an arc-shaped space between the inner wall of the reaction tube 203 and the wafer 200 so as to rise upward from the lower portion of the inner wall of the reaction tube 203 in the stacking direction of the wafer 200. It has been. 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 reaction tube 203. A plurality of the gas supply holes 250b 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. A second gas supply system is mainly configured by the second gas supply pipe 232b, the mass flow controller 241b, the valve 243b, and the second nozzle 249b. In addition, a second inert gas supply system is mainly configured by the second inert gas supply pipe 232f, the mass flow controller 241f, and the valve 243f.

The third gas supply pipe 232c is provided with a mass flow controller (MFC) 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. A third inert gas supply pipe 232g is connected to the downstream side of the valve 243c of the third gas supply pipe 232c. The third inert gas supply pipe 232g is provided with a mass flow controller 241g, which is a flow rate controller (flow rate control unit), and a valve 243g, which is an on-off valve, in order from the upstream direction. The third nozzle 249c is connected to the tip of the third gas supply pipe 232c. The third nozzle 249c is provided in an arc-shaped space between the inner wall of the reaction tube 203 and the wafer 200 so as to rise upward from the lower portion of the inner wall of the reaction tube 203 in the stacking direction of the wafer 200. It has been. The third nozzle 249c is configured as an L-shaped long nozzle. A gas supply hole 250c for supplying gas is provided on the side surface of the third nozzle 249c. 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. A third gas supply system is mainly configured by the third gas supply pipe 232c, the mass flow controller 241c, the valve 243c, and the third nozzle 249c. In addition, a third inert gas supply system is mainly configured by the third inert gas supply pipe 232g, the mass flow controller 241g, and the valve 243g.

  The fourth gas supply pipe 232d is provided with a mass flow controller (MFC) 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. A fourth inert gas supply pipe 232h is connected to the downstream side of the valve 243d of the fourth gas supply pipe 232d. The fourth inert gas supply pipe 232h is provided with a mass flow controller 241h as a flow rate controller (flow rate control unit) and a valve 243h as an on-off valve in order from the upstream direction. The fourth nozzle 249d described above is connected to the tip of the fourth gas supply pipe 232d. The fourth nozzle 249d is provided in an arc-shaped space between the inner wall of the reaction tube 203 and the wafer 200 so as to rise upward from the lower portion of the inner wall of the reaction tube 203 in the stacking direction of the wafer 200. ing. The fourth nozzle 249d is configured as an L-shaped long nozzle. A gas supply hole 250d for supplying a gas is provided on a side surface of the fourth nozzle 249d. The gas supply hole 250 d is opened to face the center of the reaction tube 203. A plurality of gas supply holes 250d 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 fourth gas supply system is mainly configured by the fourth gas supply pipe 232d, the mass flow controller 241d, the valve 243d, and the fourth nozzle 249d. In addition, a fourth inert gas supply system is mainly configured by the fourth inert gas supply pipe 232h, the mass flow controller 241h, and the valve 243h.

  As described above, the gas supply method according to the present embodiment is such that the reaction tube 203 is in an arcuate vertically long space defined by the inner wall of the reaction tube 203 and the ends of a plurality of stacked wafers 200. Gas is supplied directly from one end of the lower side or the upper side and flows from the lower side to the upper side or from the upper side to the lower side, and each wafer 200 loaded in the reaction tube 203 and the gas thus flowed are supplied. There is a big difference from the reaction method. In such a configuration, the amount of gas is relatively large (the gas concentration is relatively high) at a portion close to the gas supply unit, and a thin film formed on the wafer 200 located at that portion. The thickness becomes thicker. On the other hand, in the part away from the gas supply unit, the amount of gas that can reach the wafer 200 is reduced (because the gas concentration is relatively low), so that a thin film formed on the wafer 200 located at that part. The thickness becomes thinner. Accordingly, the film thickness of the thin film produced can be different between the upper and lower surfaces of the wafer 200 loaded in the reaction tube 203, which is not preferable as a vertical batch type apparatus.

  On the other hand, the gas supply method according to the present embodiment conveys gas via the nozzles 249a, 249b, 249c, and 249d arranged in the arcuate space described above, and opens the nozzles 249a, 249b, 249c, and 249d, respectively. Gas is blown into the reaction tube 203 for the first time in the vicinity of the wafer 200 from the gas supply holes 250a, 250b, 250c, 250d, and the main flow of the gas in the reaction tube 203 is in a direction parallel to the surface of the wafer 200; That is, the horizontal direction. With such a configuration, there is an effect that the gas can be supplied uniformly to each wafer 200 and the thickness of the thin film formed on each wafer 200 can be made uniform. The residual gas after the reaction flows toward the exhaust port, that is, the direction of the exhaust pipe 231 to be described later. The direction of the residual gas flow is appropriately specified by the position of the exhaust port and is limited to the vertical direction. It is not a thing.

From the first gas supply pipe 232a, for example, a gas (silicon-containing gas) containing silicon (Si) as a source gas is supplied into the processing chamber 201 via the mass flow controller 241a, the valve 243a, and the first nozzle 249a. . As the silicon-containing gas, for example, hexachlorodisilane (Si ₂ Cl ₆ , abbreviation: HCD) gas can be used.

From the second gas supply pipe 232b, as a reaction gas, for example, a gas containing nitrogen (N) (nitrogen-containing gas) is supplied into the processing chamber 201 through the mass flow controller 241b, the valve 243b, and the second nozzle 249b. . As the nitrogen-containing gas, for example, ammonia (NH ₃ ) gas can be used.

From the third gas supply pipe 232c, as a reaction gas, for example, a gas containing hydrogen (H) (hydrogen-containing gas) is supplied into the processing chamber 201 via the mass flow controller 241c, the valve 243c, and the third nozzle 249c. . As the hydrogen-containing gas, for example, hydrogen (H ₂ ) gas can be used.

From the fourth gas supply pipe 232d, for example, a gas containing oxygen (O) (oxygen-containing gas) is supplied as a reaction gas into the processing chamber 201 through the mass flow controller 241d, the valve 243d, and the fourth nozzle 249d. . As the oxygen-containing gas, for example, oxygen (O ₂ ) gas can be used.

From the inert gas supply pipes 232e, 232f, 232g, and 232h, for example, nitrogen (N ₂ ) gas as an inert gas is a mass flow controller 241e, 241f, 241g, 241h, valves 243e, 243f, 243g, 243h, gas, respectively. It is supplied into the processing chamber 201 through supply pipes 232a, 232b, 232c, 232d, and nozzles 249a, 249b, 249c, 249d.

  Note that, for example, when the above-described gases are supplied from the respective gas supply pipes, the first gas supply system constitutes a source gas supply system, that is, a silicon-containing gas supply system (silane-based gas supply system). The second gas supply system constitutes a nitrogen-containing gas supply system, the third gas supply system constitutes a hydrogen-containing gas supply system, and the fourth gas supply system constitutes an oxygen-containing gas supply system. A reactive gas supply system is configured by the second gas supply system, the third gas supply system, and the fourth gas supply system.

  The reaction tube 203 is provided with an exhaust pipe 231 for exhausting the atmosphere in the processing chamber 201. As shown in FIG. 2, in a cross-sectional view, the exhaust pipe 231 includes a gas supply hole 250 a of the first nozzle 249 a, a gas supply hole 250 b of the second nozzle 249 b, and a gas supply hole 250 c of the third nozzle 249 c. And the side of the fourth nozzle 249d facing the side where the gas supply holes 250d are provided, that is, the side opposite to the gas supply holes 250a, 250b, 250c and 250d across the wafer 200. In addition, as shown in FIG. 1, the exhaust pipe 231 is provided below the portion where the gas supply holes 250a, 250b, 250c, and 250d are provided in a longitudinal sectional view. With this configuration, after the gas supplied from the gas supply holes 250a, 250b, 250c, and 250d to the vicinity of the wafer 200 in the processing chamber 201 flows in the horizontal direction, that is, in a direction parallel to the surface of the wafer 200, It flows downward and is exhausted from the exhaust pipe 231. As described above, the main flow of gas in the processing chamber 201 is a flow in the horizontal direction.

From the upstream side, the exhaust pipe 231 includes a pressure sensor 245 as a pressure detector (pressure detector) for detecting the pressure in the processing chamber 201, and an APC (Auto Pressure) as a valve.
A controller) valve 244 and a vacuum pump 246 as an evacuation device are provided. The APC valve 244 is an on-off valve (pressure regulator) that can open and close the valve to stop evacuation / 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. The exhaust system is configured such that the inside of the processing chamber 201 can be evacuated so that the pressure in the processing chamber 201 becomes a predetermined pressure (degree of vacuum).

  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 installed 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 219 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 lifted vertically by a boat elevator 115 as a lifting mechanism vertically installed outside the reaction tube 203, and thereby the boat 217 is carried into and out of the processing chamber 201. It is possible.

  The boat 217 as a substrate support 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 aligned in a state where the centers are aligned with each other in multiple stages. ing. A heat insulating member 218 made of a heat resistant material such as quartz or silicon carbide is provided at the lower part of the boat 217 so that heat from the heater 207 is not easily transmitted to the seal cap 219 side. The heat insulating member 218 may be constituted by a plurality of heat insulating plates made of a heat resistant material such as quartz or silicon carbide, and a heat insulating plate holder that supports them in a horizontal posture in multiple stages.

  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 249a, 249b, 249c, and 249d, and is provided along the inner wall of the reaction tube 203.

  The controller 121 serving as a control unit (control means) includes mass flow controllers 241a, 241b, 241c, 241d, 241e, 241f, 241g, 241h, valves 243a, 243b, 243c, 243d, 243e, 243f, 243g, 243h, and pressure sensor 245. , APC valve 244, vacuum pump 246, heater 207, temperature sensor 263, rotating mechanism 267, boat elevator 115, and the like. The controller 121 controls the flow rate of various gases by the mass flow controllers 241a, 241b, 241c, 241d, 241e, 241f, 241g, 241h, the opening / closing operations of the valves 243a, 243b, 243c, 243d, 243e, 243f, 243g, 243h, APC Opening / closing of the valve 244 and pressure adjustment operation based on the pressure sensor 245, temperature adjustment operation of the heater 207 based on the temperature sensor 263, start / stop of the vacuum pump 246, rotation speed adjustment operation of the rotating mechanism 267, lifting / lowering operation of the boat elevator 115, etc. Is controlled.

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

(First sequence)
First, the first sequence of this embodiment will be described with reference to FIG. FIG. 3A is a schematic diagram showing the opening / closing timing and gas supply timing of the APC valve 244 according to the first sequence of the present embodiment.

In the first sequence of the present embodiment, a process of supplying HCD gas as a raw material gas into the processing container containing the wafer 200 and exhausting it from the exhaust pipe 231 and an NH ₃ gas as a reactive gas different from the raw material gas in the processing container. And the process of exhausting from the exhaust pipe 231 and the process of supplying O ₂ gas as a reaction gas different from the source gas into the processing vessel and exhausting from the exhaust pipe 231 are performed one or more times. As a result, a silicon oxynitride film (SiON film) having a predetermined thickness is formed on the wafer 200.

  Note that the step of supplying the HCD gas is performed under a condition where a CVD reaction occurs, and a first layer containing silicon of less than one atomic layer to several atomic layers is formed on the wafer 200. Also, in the step of supplying the HCD gas, immediately before supplying the HCD gas, the APC valve 244 provided in the exhaust pipe 231 is temporarily fully closed to temporarily close the exhaust pipe 231. This operation will be described later in detail.

Further, in the process of supplying NH ₃ gas, NH ₃ gas by supplying by thermally activated, reforming the first layer by reacting at least a portion and NH ₃ gas in the first layer Then, a second layer containing silicon and nitrogen is formed. For example, when the first layer containing several atomic layers of silicon is formed in the step of forming the first layer, a part of the surface layer may react with NH ₃ gas, or the surface layer The whole may react with NH ₃ gas. Further, NH ₃ gas may be reacted with several layers below the surface layer of the first layer of several atomic layers. When NH ₃ gas is supplied by being activated by heat rather than being activated by plasma, the soft reaction can be caused and the modification can be performed softly. Therefore, in this embodiment, the NH ₃ gas is activated by heat and supplied.

Furthermore, O in the step of supplying ₂ gas, O ₂ gas by supplying by thermally activated, modify the second layer by reacting at least a _portion, and O ₂ gas in the second layer Then, a third layer containing silicon, nitrogen and oxygen is formed. For example, when the second layer of several atomic layers is formed in the step of forming the second layer, a part of the surface layer may react with O ₂ gas, or the entire surface layer and O ₂ gas may be reacted. _Two gases may be reacted. Alternatively, several layers below the surface layer of the second layer of several atomic layers may react with O ₂ gas. The O ₂ gas can cause a soft reaction and be softly reformed when supplied by being activated by heat rather than being activated by plasma. Therefore, in the present embodiment, the O ₂ gas is activated by heat and supplied.

Hereinafter, the first sequence of the present embodiment will be specifically described. Here, a silicon oxynitride film (SiON film) is formed on the wafer 200 by using the sequence shown in FIG. 3A using an HCD gas that is a silicon-containing gas as a source gas and NH ₃ gas and O ₂ gas as reaction gases. ) Will be described.

  When a plurality of wafers 200 are loaded into the boat 217 (wafer charge), as shown in FIG. 1, the boat 217 supporting the plurality of wafers 200 is lifted by the boat elevator 115 and processed in the processing chamber 201. It is carried in (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 information (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 boat 217 is rotated by the rotation mechanism 267, whereby the wafer 200 is rotated (wafer rotation). Thereafter, the following three steps are sequentially executed.

[Step 1]
First, immediately before supplying the HCD gas into the processing container, the APC valve 244 provided in the exhaust pipe 231 is temporarily fully closed, and the exhaust pipe 231 is temporarily closed. While the APC valve 244 is fully closed, the processing chamber is continuously exhausted through the exhaust pipe 231. That is, the exhaust in the processing chamber 201 is stopped by fully closing the APC valve 244, but the state in which the vacuum pump 246 is operated is maintained and the exhaust pipe 231 is continuously exhausted.

  When the exhaust in the processing chamber 201 is stopped, the pressure in the processing chamber 201 gradually increases. When the predetermined time has elapsed, the valve 243a of the first gas supply pipe 232a is opened, the HCD gas is caused to flow into the first gas supply pipe 232a, and the opening operation of the APC valve 244 in the fully closed state is started. The HCD gas is supplied while gradually increasing the opening degree of the APC valve 244.

The flow rate of the HCD gas flowing through the first gas supply pipe 232a is adjusted by the mass flow controller 241a. The HCD gas whose flow rate is adjusted is supplied into the processing chamber 201 from the gas supply hole 250a of the first nozzle 249a, flows in the horizontal direction on the surface of the wafer 200, and is exhausted from the exhaust pipe 231. At this time, the valve 243e is opened at the same time, and an inert gas such as N ₂ gas is allowed to flow into the first inert gas supply pipe 232e. The flow rate of N ₂ gas that has flowed through the first inert gas supply pipe 232e is adjusted by the mass flow controller 241e. The N ₂ gas whose flow rate has been adjusted is supplied into the processing chamber 201 together with the HCD gas, flows in the horizontal direction on the surface of the wafer 200, and is exhausted from the exhaust pipe 231. At this time, the main flow of gas in the processing chamber 201 is a flow in the horizontal direction, that is, in a direction parallel to the surface of the wafer 200.

  At this time, the opening degree of the APC valve 244 is appropriately adjusted so that the pressure in the processing chamber 201 is, for example, a pressure in the range of 10 to 1000 Pa. As described above, in this embodiment, immediately before supplying the HCD gas into the processing container, the APC valve 244 provided in the exhaust pipe 231 is temporarily fully closed to temporarily close the exhaust pipe 231. . Thereby, the pressure in the processing chamber 201 can be quickly raised in a short time, and the maximum pressure (attainment pressure) in the processing chamber 201 at the time of supplying the HCD gas can be increased. In particular, the supply of HCD gas into the processing container is performed while gradually increasing the opening degree of the APC valve 244. Thereby, the pressure in the processing chamber 201 at the time of supplying the HCD gas can be increased in a shorter time, and the maximum pressure (attainment pressure) in the processing chamber 201 at the time of supplying the HCD gas can be further increased.

  The supply flow rate of the HCD gas controlled by the mass flow controller 241a is set to a flow rate in the range of 10 to 1000 sccm, for example. As described above, in this embodiment, immediately before supplying the HCD gas into the processing container, the APC valve 244 provided in the exhaust pipe 231 is temporarily fully closed to temporarily close the exhaust pipe 231. . Thereby, even when the flow rate of the HCD gas supplied into the processing container is small, the pressure in the processing chamber 201 is quickly increased in a short time, and the maximum pressure (attainment pressure) in the processing chamber 201 at the time of supplying the HCD gas is increased. be able to.

The time for exposing the HCD gas to the wafer 200, that is, the gas supply time (irradiation time) is, for example, a time within the range of 1 to 120 seconds. At this time, the temperature of the heater 207 is set to a temperature at which a CVD reaction occurs in the processing chamber 201, that is, a temperature at which the temperature of the wafer 200 becomes a temperature within a range of 350 to 700 ° C., for example. Note that when the temperature of the wafer 200 is as low as less than 350 ° C., silicon-containing gas such as HCD is difficult to be thermally decomposed. Further, when the temperature of the wafer 200 exceeds 700 ° C., the CVD reaction becomes strong, and the uniformity tends to deteriorate. Therefore, the temperature of the wafer 200 is preferably set to a temperature in the range of 350 to 700 ° C., for example.

  By supplying the HCD gas, a first layer containing silicon 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). 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. When the thickness of the silicon layer formed on the wafer 200 exceeds several atomic layers, the nitriding action in step 2 described later and the oxidizing action in step 3 described later do not reach the entire silicon layer. . Further, the minimum value of the silicon layer that can be formed on the wafer 200 is less than one atomic layer. Therefore, the thickness of the silicon layer is preferably less than one atomic layer to several atomic layers.

  Note that, under the condition that the HCD gas does not self-decompose, the HCD chemisorbed layer is formed by the chemical adsorption of HCD on the wafer 200. However, the condition under which the CVD reaction occurs as in this embodiment, that is, the HCD gas. Under the condition of self-decomposing, the HCD gas is thermally decomposed and silicon is deposited on the wafer 200 to form a silicon layer. Note that it is preferable to form a silicon layer on the wafer 200 as in this embodiment because the deposition rate can be increased, rather than forming an HCD chemical adsorption layer on the wafer 200. As described above, in the present embodiment, when supplying the HCD gas, the pressure in the processing chamber 201 is quickly increased in a short time, and the maximum pressure (attainment pressure) in the processing chamber 201 at the time of supplying the HCD gas. Is increasing. As a result, a sufficient amount of HCD gas can be uniformly supplied to the wafer 200, and the probability of adsorption of the HCD gas onto the underlying film on the surface of the wafer 200 and the silicon on the underlying film on the surface of the wafer 200 are determined. The deposition probability can be increased, the film formation rate can be further improved, and the film thickness uniformity within and between the wafers can be further improved.

After the silicon layer is formed, the valve 243a is closed and the supply of HCD gas is stopped. At this time, the APC valve 244 of the exhaust pipe 231 is kept open, the processing chamber 201 is evacuated by the vacuum pump 246, and the unreacted or remaining HCD gas remaining in the processing chamber 201 is contributed to the formation of the silicon layer. Excluded from the processing chamber 201. At this time, the valve 243e is kept open and the supply of N ₂ gas into the processing chamber 201 is maintained. As a result, it is possible to enhance the effect of removing the unreacted HCD gas remaining in the processing chamber 201 or after contributing to the formation of the silicon layer from the processing chamber 201. At this time, the gas remaining in the processing chamber 201 may not be completely removed, and the inside of the processing chamber 201 may not be completely purged. If the amount of gas remaining in the processing chamber 201 is very small, there will be no adverse effect in the subsequent step 2. At this time, the flow rate of the N ₂ gas supplied into the processing chamber 201 does not need to be a large flow rate. Purging to such an extent that no occurrence occurs can be performed. Thus, by not completely purging the inside of the processing chamber 201, the purge time can be shortened and the throughput can be improved. In addition, consumption of N ₂ gas can be minimized.

Examples of the silicon-containing gas include not only HCD gas but also inorganic raw materials such as dichlorosilane (SiH ₂ Cl ₂ , abbreviation: DCS) gas and monosilane (SiH ₄ ) gas, as well as aminosilane-based tetrakisdimethylaminosilane (Si (N ( CH ₃ ) ₂ ) ₄ , abbreviation: 4DMAS) gas, trisdimethylaminosilane (Si (N (CH ₃ ) ₂ ) ₃ H, abbreviation: 3DMAS) gas, bisdiethylaminosilane (Si (N (C ₂ H ₅ ) ₂ ) Organic raw materials such as ₂ H ₂ , abbreviation: 2DEAS) gas, and bistally butylaminosilane (SiH ₂ (NH (C ₄ H ₉ )) ₂ , abbreviation: BTBAS) gas may be used. 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 2]
After the residual gas in the processing chamber 201 is removed, the valve 243b of the second gas supply pipe 232b is opened, and NH ₃ gas is allowed to flow into the second gas supply pipe 232b. 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 processing chamber 201 from the gas supply hole 250 b of the second nozzle 249 b, flows in the horizontal direction on the surface of the wafer 200, and is exhausted from the exhaust pipe 231. At the same time, the valve 243f is opened and N ₂ gas is caused to flow into the second inert gas supply pipe 232f. The N ₂ gas is supplied into the processing chamber 201 together with the NH ₃ gas, flows horizontally on the surface of the wafer 200, and is exhausted from the exhaust pipe 231. At this time, the main flow of gas in the processing chamber 201 is a flow in the horizontal direction, that is, in a direction parallel to the surface of the wafer 200.

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 50 to 3000 Pa. The supply flow rate of NH ₃ gas controlled by the mass flow controller 241b is, for example, a flow rate in the range of 100 to 10,000 sccm. The time for exposing the wafer 200 to the NH ₃ gas, that is, the gas supply time (irradiation time) is, for example, a time within the range of 1 to 120 seconds. The temperature of the heater 207 at this time is set to a temperature at which the temperature of the wafer 200 becomes a temperature within the range of 350 to 700 ° C., for example, as in Step 1. Since NH ₃ gas has a high reaction temperature and does not easily react at the wafer temperature as described above, it can be thermally activated by setting the pressure in the processing chamber 201 to a relatively high pressure as described above. Yes. Note that the NH ₃ gas activated by heat (non-plasma) and supplied can cause a soft reaction, and nitridation described later can be performed softly.

At this time, the gas flowing into the processing chamber 201 is a thermally activated NH ₃ gas, and no HCD gas is flowing into the processing chamber 201. Therefore, the activated NH ₃ gas does not cause a gas phase reaction, and reacts with at least a part of the silicon layer as the first layer formed on the wafer 200 in Step 1. As a result, the silicon layer is nitrided and modified into a second layer containing silicon and nitrogen, that is, a silicon nitride layer (SiN layer).

Thereafter, 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 exhaust pipe 231 is kept open, the inside of 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 treated. Exclude from the chamber 201. At this time, the supply of N ₂ gas into the processing chamber 201 is maintained while the valve 243f is kept open. Thereby, it is possible to enhance the effect of removing unreacted NH ₃ gas remaining in the processing chamber 201 or after contributing to nitridation from the processing chamber 201.

As the nitrogen-containing gas, in addition to NH ₃ gas, nitrogen (N ₂ ) gas, nitrogen trifluoride (NF ₃ ) gas, hydrazine (N ₂ H ₄ ) gas, N ₃ H ₈ gas, or the like may be used.

[Step 3]
After the residual gas in the processing chamber 201 is removed, the valve 243d of the fourth gas supply pipe 232d is opened, and O ₂ gas is caused to flow into the fourth gas supply pipe 232d. The flow rate of the O ₂ gas that has flowed through the fourth gas supply pipe 232d is adjusted by the mass flow controller 241d. The O ₂ gas whose flow rate has been adjusted is activated by heat, and from the gas supply hole 250d of the fourth nozzle 249d, the processing chamber 201.
And flows horizontally on the surface of the wafer 200 and is exhausted from the exhaust pipe 231. At the same time, the valve 243h is opened and N ₂ gas is allowed to flow into the fourth inert gas supply pipe 232h. The N ₂ gas is supplied into the processing chamber 201 together with the O ₂ gas, flows horizontally on the surface of the wafer 200, and is exhausted from the exhaust pipe 231. At this time, the main flow of gas in the processing chamber 201 is a flow in the horizontal direction, that is, in a direction parallel to the surface of the wafer 200. The O ₂ gas is not limited to being activated by heat, but can be activated by plasma.

When the O ₂ gas is activated and flowed by heat, the APC valve 244 is appropriately adjusted so that the pressure in the processing chamber 201 is, for example, in the range of 1 to 3000 Pa. The supply flow rate of the O ₂ gas controlled by the mass flow controller 241d is, for example, a flow rate in the range of 100 to 5000 sccm (0.1 to 5 slm). The time for exposing the wafer 200 to the O ₂ gas, that is, the gas supply time (irradiation time) is, for example, a time within a range of 1 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 350 to 700 ° C., for example, as in Steps 1 and 2. O ₂ gas is thermally activated under the conditions as described above. Note that when the O ₂ gas is activated by heat (non-plasma) and supplied, a soft reaction can be caused, and oxidation described later can be performed softly.

At this time, the gas flowing into the processing chamber 201 is a thermally activated O ₂ gas, and neither the HCD gas nor the NH ₃ gas is flowing into the processing chamber 201. Therefore, the activated O ₂ gas does not cause a gas phase reaction, and reacts with at least a part of the SiN layer as the second layer formed on the wafer 200 in Step 2. As a result, the SiN layer is oxidized and modified into a third layer containing silicon, nitrogen and oxygen, that is, a silicon oxynitride layer (SiON layer).

Thereafter, the valve 243d of the fourth gas supply pipe 232d is closed, and the supply of O ₂ gas is stopped. At this time, the APC valve 244 of the exhaust pipe 231 is kept open, the processing chamber 201 is evacuated by the vacuum pump 246, and the O ₂ gas remaining in the processing chamber 201 and contributing to oxidation is treated. Exclude from the chamber 201. At this time, the supply of the N ₂ gas into the processing chamber 201 is maintained while the valve 243h is kept open. This enhances the effect of eliminating the unreacted or remaining O ₂ gas remaining in the processing chamber 201 from the processing chamber 201.

As the oxygen-containing gas, in addition to O ₂ gas, ozone (O ₃ ) gas, nitrogen monoxide (NO) gas, nitrous oxide (N ₂ O) gas, or the like may be used.

  By performing steps 1 to 3 described above as one cycle and performing this cycle one or more times, a thin film containing silicon, nitrogen and oxygen having a predetermined thickness, that is, a silicon oxynitride film (SiON film) is formed on the wafer 200. Can be membrane. The above cycle is preferably repeated a plurality of times.

When a film forming process for forming a silicon oxynitride film having a predetermined thickness is performed, an inert gas such as N ₂ is supplied into the processing chamber 201 and exhausted, whereby the processing 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 to open the lower end of the reaction tube 203, 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. Unloaded (boat unload). Thereafter, the processed wafer 200 is taken out from the boat 217 (wafer discharge).

  According to this embodiment, immediately before supplying the HCD gas into the processing container in step 1, the APC valve 244 provided in the exhaust pipe 231 is temporarily fully closed to temporarily close the exhaust pipe 231. . Thereby, when supplying the HCD gas into the processing chamber 201, the pressure in the processing chamber 201 can be quickly increased in a short time, and the maximum pressure (attainment pressure) in the processing chamber 201 when the HCD gas is supplied can be increased. it can. As a result, a sufficient amount of HCD gas can be uniformly supplied to the wafer 200, the probability of adsorption of the HCD gas onto the base film on the surface of the wafer 200, and the silicon on the base film on the surface of the wafer 200. The probability of deposition can be increased. Then, the deposition rate of the silicon oxynitride film (SiON film) on the wafer 200 can be improved, and the film thickness uniformity within the wafer surface and between the wafers can be improved. Even when the flow rate of the HCD gas supplied into the processing container is small, immediately before supplying the HCD gas into the processing container, the APC valve 244 provided in the exhaust pipe 231 is temporarily fully closed to exhaust the exhaust pipe. By temporarily closing 231, the above-described effects can be obtained.

  Further, according to the present embodiment, the supply of the HCD gas into the processing container in Step 1 is performed while gradually increasing the opening degree of the APC valve 244. Thereby, when supplying the HCD gas into the processing chamber 201, the pressure in the processing chamber 201 is further increased in a short time, and the maximum pressure (attainment pressure) in the processing chamber 201 at the time of supplying the HCD gas is further increased. Can do. As a result, a sufficient amount of HCD gas can be uniformly supplied to the wafer 200, the probability of adsorption of the HCD gas onto the base film on the surface of the wafer 200, and the silicon on the base film on the surface of the wafer 200. It is possible to increase the deposition probability, improve the deposition rate of the silicon oxynitride film (SiON film) on the wafer 200, and improve the film thickness uniformity within the wafer surface and between the wafers.

  Further, according to the present embodiment, when the APC valve 244 is temporarily fully closed and the exhaust pipe 231 is temporarily closed in step 1, the exhaust to the inside of the processing container through the exhaust pipe 231 is continuously performed. . That is, the state where the vacuum pump 246 is operated is maintained, and the exhaust pipe 231 is continuously exhausted. Thereby, when the APC valve 244 is opened, the backflow of the exhaust gas from the exhaust pipe 231 into the processing chamber 201 can be prevented. In addition, since the APC valve 244 is opened when the supply of the HCD gas is stopped, the processing chamber 201 can be quickly evacuated and decompressed.

  FIG. 5A is a schematic diagram showing a pressure change in the processing chamber 201 when the APC valve 244 is fully closed immediately before supplying the HCD gas, and FIG. 5B is a diagram showing the APC valve being opened. It is a schematic diagram which shows the pressure change in a process chamber at the time of setting. According to FIG. 5A, it can be seen that the pressure in the processing chamber 201 gradually increases by fully closing the APC valve 244 immediately before supplying the HCD gas. Then, it can be seen that the pressure in the processing chamber 201 further increases by starting the opening operation of the APC valve 244 simultaneously with the start of the supply of the HCD gas and gradually increasing the opening degree of the APC valve 244. From FIG. 5B in which the APC valve is kept open, it can be seen that the pressure in the processing chamber 201 increases in a short time and the maximum pressure (attainment pressure) at the time of supplying the HCD gas increases. Note that, since the APC valve 244 is open when the supply of the HCD gas is stopped, it can be seen that the processing chamber 201 is evacuated / depressurized quickly as in FIG. 5B.

(Second sequence)
Subsequently, the second sequence of the present embodiment will be described with reference to FIG. FIG. 4A is a schematic diagram showing the opening / closing timing of the APC valve 244 and the gas supply timing according to the second sequence of the present embodiment.

In the second sequence of the present embodiment, a process of supplying HCD gas as a source gas into the processing container containing the wafer 200 and exhausting it from the exhaust pipe 231 and a hydrogen-containing gas as a reactive gas different from the source gas in the processing container. The process of supplying the H ₂ gas as an oxygen gas and the O ₂ gas as an oxygen-containing gas and exhausting it from the exhaust pipe 231 is performed as one cycle, and this cycle is performed once or more, so that silicon oxide having a predetermined film thickness is formed on the wafer 200. A film (SiO film) is formed.

  Note that the step of supplying the HCD gas is performed under a condition in which a CVD reaction occurs as in the first sequence, and a first layer containing silicon of less than one atomic layer to several atomic layers is formed on the wafer 200. . Further, in the step of supplying the HCD gas, just like the first sequence, immediately before supplying the HCD gas, the APC valve 244 provided in the exhaust pipe 231 is temporarily fully closed to temporarily close the exhaust pipe 231. Block.

Further, in the step of supplying H ₂ gas and O ₂ gas, by supplying H ₂ gas and O ₂ gas into the processing vessel is under pressure (vacuum) atmosphere at less than atmospheric pressure, H ₂ in the process vessel The gas and O ₂ gas are reacted to generate an oxygen-containing oxidizing species (atomic oxygen or the like), and the first layer is oxidized by the oxidizing species to form a second layer containing silicon and oxygen. O ₂ gas and H ₂ gas can cause a soft reaction and be softly oxidized when activated and supplied with heat rather than activated with plasma. Therefore, in this embodiment, the O ₂ gas and the H ₂ gas are activated by heat and supplied.

  Hereinafter, the second sequence of the present embodiment will be specifically described.

  In the second sequence, wafer charging, boat loading, pressure adjustment, temperature control, and wafer rotation are performed in the same manner as in the first sequence. Thereafter, two steps to be described later are sequentially executed.

[Step 1]
Step 1 is performed in the same manner as Step 1 of the first sequence. That is, the processing conditions in Step 1, the reaction to be generated, the layer to be formed, the thickness of the layer to be formed, examples of gas species, and the like are the same as those in Step 1 in the first sequence. That is, in this step, a silicon layer as a first layer is formed on the wafer 200 by supplying the HCD gas into the processing chamber 201.

  Also in the second sequence, immediately before supplying the HCD gas into the processing container, the APC valve 244 provided in the exhaust pipe 231 is temporarily fully closed to temporarily close the exhaust pipe 231, The exhaust in the processing chamber 201 is temporarily stopped. Thereby, when supplying the HCD gas into the processing chamber 201, the pressure in the processing chamber 201 can be quickly increased in a short time, and the maximum pressure (attainment pressure) in the processing chamber 201 when the HCD gas is supplied can be increased. it can. Even when the HCD gas has a small flow rate, similarly, the pressure in the processing chamber 201 can be quickly increased in a short time, and the maximum pressure (attainment pressure) in the processing chamber 201 when the HCD gas is supplied can be increased. it can.

[Step 2]
After step 1 is completed and residual gas in the processing chamber 201 is removed, the valve 243c of the third gas supply pipe 232c and the valve 243d of the fourth gas supply pipe 232d are opened, and the inside of the third gas supply pipe 232c and the fourth gas supply pipe 232c are opened. H ₂ gas and O ₂ gas are allowed to flow through the gas supply pipe 232d, respectively. The flow rates of the H ₂ gas and the O ₂ gas that have flowed through the third gas supply pipe 232c and the fourth gas supply pipe 232d are adjusted by the mass flow controllers 241c and 241d, respectively. The flow-adjusted H ₂ gas and O ₂ gas are activated by heat and supplied into the processing chamber 201 from the gas supply hole 250c of the third nozzle 249c and the gas supply hole 250d of the fourth nozzle 249d, respectively. In the processing chamber 201, the H ₂ gas and the O ₂ gas react with each other to generate an oxygen-containing oxidizing species (atomic oxygen or the like). The generated oxidized species flow on the surface of the wafer 200 in the horizontal direction and are exhausted from the exhaust pipe 231. At the same time, the valves 243g and 243h are opened, and N ₂ gas is caused to flow into the third inert gas supply pipe 232g and the fourth inert gas supply pipe 232h. The N ₂ gas is supplied into the processing chamber 201 together with the H ₂ gas and the O ₂ gas, flows in the horizontal direction on the surface of the wafer 200, and is exhausted from the exhaust pipe 231. At this time, the main flow of gas in the processing chamber 201 is a flow in the horizontal direction, that is, in a direction parallel to the surface of the wafer 200. Note that the H ₂ gas and the O ₂ gas are not limited to be activated by heat, but can be activated by plasma.

When the H ₂ gas and the O ₂ gas are activated and flowed by heat, the APC valve 244 is appropriately adjusted so that the pressure in the processing chamber 201 is, for example, in the range of 1 to 3000 Pa. The supply flow rate of H ₂ gas controlled by the mass flow controller 241c is, for example, a flow rate in the range of 10 to 5000 sccm (0.01 to 5 slm), and the supply flow rate of O ₂ gas controlled by the mass flow controller 241d is, for example, 100 to 5000 sccm. The flow rate is within the range of (0.1 to 5 slm). The time during which the wafer 200 is exposed to the generated oxidized species, that is, the gas supply time (irradiation time) is, for example, a time within the range of 1 to 120 seconds. The temperature of the heater 207 at this time is set to a temperature at which the temperature of the wafer 200 becomes a temperature within the range of 350 to 700 ° C., as in Step 1. H ₂ gas and O ₂ gas are thermally activated under the conditions as described above. Note that the H ₂ gas and the O ₂ gas activated by heat (non-plasma) and supplied can cause a soft reaction, and the later-described oxidation can be performed softly.

At this time, the gas flowing into the processing chamber 201 is thermally activated H ₂ gas and O ₂ gas, and no HCD gas is flowing into the processing chamber 201. Therefore, the generated oxidized species does not cause a gas phase reaction, and reacts with at least a part of the Si layer as the first layer formed on the wafer 200 in Step 1. As a result, the Si layer is oxidized and modified into a second layer containing silicon and oxygen, that is, a silicon oxide layer (SiO layer).

Thereafter, the valve 243c of the third gas supply pipe 232c and the valve 243d of the fourth gas supply pipe 232d are closed to stop the supply of H ₂ gas and O ₂ gas. At this time, the APC valve 244 of the exhaust pipe 231 is kept open, the inside of the processing chamber 201 is evacuated by the vacuum pump 246, and the H ₂ gas and O ₂ remaining in the processing chamber 201 and contributed to oxidation are left behind. _Two gases are excluded from the processing chamber 201. At this time, the valves 243g and 243h are kept open and the supply of N ₂ gas into the processing chamber 201 is maintained. As a result, the effect of removing the H ₂ gas and the O ₂ gas remaining in the processing chamber 201 after being unreacted or contributing to oxidation from the processing chamber 201 is enhanced.

As the oxygen-containing gas, ozone (O ₃ ) gas, water vapor (H ₂ O), or the like may be used in addition to O ₂ gas. Further, as the hydrogen-containing gas, deuterium besides _{H 2} gas _(D 2), may be used water vapor _(H 2 O) and the like.

  By performing steps 1 and 2 described above as one cycle and performing this cycle once or more, a thin film containing silicon and oxygen having a predetermined thickness, that is, a silicon oxide film (SiO film) is formed on the wafer 200. Can do. The above cycle is preferably repeated a plurality of times.

In the present embodiment, the same effect as the first sequence is obtained. In the process of supplying H ₂ gas and O ₂ gas (step 2), the processing container is supplied by supplying H ₂ gas and O ₂ gas into the processing container under a pressure (decompression) atmosphere less than atmospheric pressure. H ₂ gas and O ₂ gas are caused to react with each other to generate oxygen-containing oxidizing species (atomic oxygen or the like), and the first layer is oxidized by the oxidizing species. As a result, the oxidation can be performed with a higher oxidizing power than the oxidation with a single oxygen-containing gas such as O ₂ gas, and the deposition rate of the silicon oxide film (SiO film) on the wafer 200 can be improved. it can.

<Other Embodiments of the Present Invention>
In the embodiment described above, the APC valve 244 provided in the exhaust pipe 231 is temporarily fully closed and the exhaust pipe 231 is temporarily closed only immediately before supplying the HCD gas into the processing container. It was. However, the present invention is not limited to such a form. That is, immediately before supplying a reaction gas such as NH ₃ gas, O ₂ gas, or H ₂ gas into the processing container, the APC valve 244 provided in the exhaust pipe 231 is temporarily fully closed to exhaust the exhaust pipe 231. May be temporarily closed.

  Thereby, when supplying the reaction gas into the processing chamber 201, the pressure in the processing chamber 201 can be quickly increased in a short time, and the maximum pressure (attainment pressure) in the processing chamber 201 when the reaction gas is supplied can be increased. it can. As a result, a sufficient amount of reaction gas can be uniformly supplied to the wafer 200, the probability of reaction between the silicon layer formed on the surface of the wafer 200 and the reaction gas is increased, and the silicon layer is nitrided, oxidized, etc. The film formation rate can be further improved, and the film quality uniformity of the silicon oxynitride film (SiON film) or the silicon oxide film (SiO film) within the wafer surface and between the wafers can be improved.

  In the above-described embodiment, the case where the APC valve 244 is used alone as a valve provided in the exhaust pipe 231 has been described, but the present invention is not limited to such a form. For example, as the valve provided in the exhaust pipe 231, an open / close valve that does not have a pressure control function may be used alone, or an open / close valve that does not have a pressure control function and an APC valve may be used in combination.

  In the above-described embodiment, an example of forming a silicon oxynitride film (SiON film) on the wafer 200 using a silicon-containing gas as a source gas, a nitrogen-containing gas and an oxygen-containing gas as reaction gases, and a source gas An example in which a silicon oxide film (SiO film) is formed on the wafer 200 using a hydrogen-containing gas and an oxygen-containing gas as reaction gases has been described. However, the present invention is not limited to the above-described embodiment, and can be applied to the case where other thin films are formed.

  For example, the present invention uses a silicon-containing gas, an aluminum-containing gas, a titanium-containing gas, a tantalum-containing gas, or a boron-containing gas as a source gas, and a reactive gas containing a nitrogen-containing gas, a hydrogen-containing gas, an oxygen-containing gas, carbon Also applicable to the case where a nitride film, oxide film, oxynitride film, carbide film, or the like containing any element of silicon, aluminum, titanium, tantalum, or boron is formed on the wafer 200 using at least one of the contained gases. can do.

In this case, as the aluminum-containing gas, for example, trimethylaluminum (Al (CH ₃ ) ₃ , abbreviation: TMA) gas can be used. As the titanium-containing gas, for example, titanium tetrachloride (TiCl ₄ ) gas or tetrakisdimethylamino titanium (Ti [N (CH ₃ ) ₂ ] ₄ , abbreviation: TDMAT) gas can be used. As the tantalum-containing gas, for example, tantalum pentachloride (TaCl ₅ ) gas or pentaethoxy tantalum (Ta (OC ₂ H ₅ ) ₅ , abbreviation: PET) gas can be used. As the boron-containing gas, for example, boron trichloride (BCl ₃ ) gas or diborane (B ₂ H ₆ ) gas can be used. Further, as the carbon-containing gas, for example, propylene (C ₃ H ₆ ) gas or ethylene (C ₂ H ₄ ) gas can be used.

Example 1
<Verification of SiON film deposition rate and film thickness uniformity>
Using the substrate processing apparatus described in the above embodiment, a SiON film (Example) formed using the same method as the first sequence, and a SiON film (Comparative Example) formed using a conventional method are formed. Speed and film thickness uniformity between wafers were measured respectively. The SiON film according to the example was formed using a sequence similar to the above-described first sequence shown in FIG. Further, the SiON film according to the comparative example was formed using the conventional sequence shown in FIG. 3B, that is, a sequence in which the APC valve is kept open immediately before supplying the HCD gas. It should be noted that conditions other than the opening / closing operation of the APC valve, that is, the processing chamber pressure (processing pressure), the wafer temperature (processing temperature), the HCD gas, NH ₃ gas, O The supply flow rate and supply time of ₂ gas and N ₂ gas were common to the examples and comparative examples. In both the examples and the comparative examples, 100 wafers were stacked in a horizontal posture in a processing container and accommodated to form a film.

  FIG. 6 is a graph showing the deposition rate of the SiON film according to the example of the present invention together with the deposition rate of the SiON film according to the comparative example. The vertical axis in FIG. 6 indicates the deposition rate of the SiON film, that is, the thickness (Å / cycle) of the SiON film formed per cycle. The horizontal axis indicates the substrate processing position, that is, the lower part (Bottom), the central part (Center), and the upper part (Top) in this order. Note that. In FIG. 6, Δ marks indicate examples, and □ marks indicate comparative examples.

  As shown in FIG. 6, the film formation speed of the example (Δ mark) is the same as that of the comparative example (□ mark) at any of the substrate processing positions at the bottom (Bottom), the center (Center), and the top (Top). It was found that each improved by 30% or more compared to the film formation rate.

  It was also found that the film thickness uniformity between the wafers according to the example was improved as compared with the film thickness uniformity between the wafers according to the comparative example. Specifically, the in-plane average film thickness of the SiON film was measured for each of the wafers of the example and the comparative example (100 sheets each), and the uniformity was determined as the maximum value Tmax of 100 in-plane average film thicknesses. -The minimum value Tmin of 100 in-plane average film thicknesses / (average value Tave of 100 in-plane average film thicknesses) x 100 (%) was evaluated using the following formula. However, in the example, it was reduced to 1.2%, and it was found that the film thickness uniformity between the wafers was improved in the example.

(Example 2)
<Verification of film thickness uniformity of SiO film>
Using the substrate processing apparatus described in the above-described embodiment, the SiO film (Example) formed using the same method as the second sequence, and the SiO film (Comparative Example) formed using the conventional method are used between wafers. The film thickness uniformity was measured. The SiO film according to the example was formed using the same sequence as the above-described second sequence shown in FIG. In addition, the SiO film according to the comparative example was formed using the conventional sequence shown in FIG. 4B, that is, the sequence in which the APC valve is kept open immediately before supplying the HCD gas. It should be noted that conditions other than the opening / closing operation of the APC valve, that is, the processing chamber pressure (processing pressure), wafer temperature (processing temperature), HCD gas, H ₂ gas, O in a steady state before and after the APC valve is closed. The supply flow rate and supply time of ₂ gas and N ₂ gas were common to the examples and comparative examples. In both the examples and the comparative examples, 100 wafers were stacked in a horizontal posture in a processing container and accommodated to form a film.

As a result, it was found that the film thickness uniformity between the wafers according to the example was improved as compared with the film thickness uniformity between the wafers according to the comparative example. Specifically, the in-plane average film thickness of the SiO film was measured for each of the wafers of the example and the comparative example (100 sheets each), and the uniformity was determined as the maximum value Tmax of the 100 in-plane average film thicknesses. -The minimum value Tmin of 100 sheets in the in-plane average film thickness) / (average value Tave of 100 sheets in the in-plane average film thickness) x 100 (%) was evaluated using the formula 1.1. However, in the example, it was reduced to 0.6%, and it was found that the film thickness uniformity between the wafers was improved in the example.

Example 3
<Verification of pressure change in processing chamber>
When the substrate processing apparatus described in the above embodiment is used and the APC valve is temporarily fully closed immediately before supplying the HCD gas (Example), or when the HCD gas is supplied with the APC valve opened (Comparative Example) ), The pressure change in the processing chamber was measured. The conditions other than the opening / closing operation of the APC valve, that is, the processing chamber pressure (processing pressure) before closing the APC valve, the processing chamber temperature, the supply flow rate and the supply time of the HCD gas and the N ₂ gas are shown in the example and the comparative example. And common.

  FIG. 7 is a graph showing the pressure change in the processing chamber according to the embodiment of the present invention together with the pressure change in the processing chamber according to the comparative example. The vertical axis in FIG. 7 indicates the pressure (Pa) in the processing chamber. The horizontal axis indicates the elapsed time (sec) from the start of the supply of HCD gas. Note that. In FIG. 7, Δ marks indicate examples, and □ marks indicate comparative examples.

As shown in FIG. 7, the pressure in the processing chamber according to the example (Δ mark) is higher than that in the processing chamber according to the comparative example (□), and the pressure in the processing chamber is quickly and quickly. You can see that it rises. Moreover, it turns out that the maximum pressure (attainment pressure) in the process chamber at the time of HCD gas supply which concerns on an Example is high compared with a comparative example. That is, in the example, it can be seen that the HCD gas can be more efficiently supplied to the wafer. Note that, since the APC valve 244 is opened when the supply of the HCD gas is stopped, it can be seen that the processing chamber is evacuated and decompressed as quickly as in the comparative example. Note that when the supply of HCD gas was started (at 0 sec in the figure), the pressure of the example was slightly higher than that of the comparative example, but this is because the APC valve is temporarily full immediately before supplying the HCD gas. This is because the exhaust in the processing chamber is stopped by closing, and the pressure in the processing chamber gradually increases due to the continuously supplied N ₂ gas.

<Preferred embodiment of the present invention>
Hereinafter, preferred embodiments of the present invention will be additionally described.

According to one aspect of the invention,
Supplying a source gas into a processing container containing a substrate and exhausting it from an exhaust pipe;
Supplying a reaction gas different from the source gas into the processing vessel and exhausting the exhaust gas from the exhaust pipe;
1 cycle, and performing this cycle one or more times to form a thin film with a predetermined thickness on the substrate,
In the step of supplying the source gas, a method of manufacturing a semiconductor device is provided in which the valve provided in the exhaust pipe is temporarily fully closed to temporarily close the exhaust pipe immediately before the source gas is supplied. Is done.

  Preferably, in the step of forming the thin film having the predetermined film thickness, the valve is kept open except when the valve is temporarily fully closed and the exhaust pipe is temporarily closed.

  Preferably, in the step of forming the thin film having the predetermined film thickness, the exhaust of the processing container through the exhaust pipe is continuously performed.

  Preferably, an exhaust device is connected to the exhaust pipe, and the exhaust device is kept in an operating state in the step of forming the thin film having the predetermined film thickness.

Preferably, in the step of supplying the source gas, immediately before supplying the source gas,
The valve is temporarily fully closed to temporarily close the exhaust pipe, and then the valve is opened to supply the source gas.

  Preferably, in the step of supplying the source gas, immediately before the source gas is supplied, the valve is temporarily fully closed to temporarily close the exhaust pipe, and then the opening of the valve is increased. The raw material gas is supplied while gradually increasing it.

According to another aspect of the invention,
A processing container for accommodating and processing the substrate;
A raw material gas supply system for supplying a raw material gas into the processing vessel;
A reaction gas supply system for supplying a reaction gas different from the source gas into the processing vessel;
An exhaust pipe for exhausting the inside of the processing vessel;
A valve provided in the exhaust pipe;
An exhaust device connected to the exhaust pipe;
The process of supplying the raw material gas into the processing container containing the substrate and exhausting it from the exhaust pipe, and the process of supplying the reaction gas into the processing container and exhausting from the exhaust pipe are defined as one cycle. By performing the cycle one or more times, a process for forming a thin film with a predetermined thickness on the substrate is performed, and the valve is temporarily fully closed immediately before supplying the source gas into the processing container. A substrate processing apparatus is provided that includes a control unit that controls the source gas supply system, the reaction gas supply system, the valve, and the exhaust device so as to temporarily close the exhaust pipe.

  Preferably, when performing the process of forming the thin film having the predetermined film thickness, the control unit opens the valve except when the valve is temporarily fully closed and the exhaust pipe is temporarily closed. The valve is controlled to maintain a closed state.

  Preferably, the control unit controls the exhaust device so as to continuously exhaust the inside of the processing container through the exhaust pipe when performing the process of forming the thin film having the predetermined film thickness. Composed.

  Preferably, the control unit is configured to control the exhaust device so as to maintain a state in which the exhaust device is operated when performing a process of forming the thin film having the predetermined thickness.

  Further preferably, when performing the process of further supplying the source gas, the control unit temporarily fully closes the valve and temporarily closes the exhaust pipe immediately before supplying the source gas. Thereafter, the valve and the source gas supply system are controlled to open the valve and supply the source gas.

  Further preferably, when performing the process of further supplying the source gas, the control unit temporarily fully closes the valve and temporarily closes the exhaust pipe immediately before supplying the source gas. Thereafter, the valve and the source gas supply system are controlled so as to supply the source gas while gradually increasing the opening of the valve.

121 Controller (control unit)
200 wafer (substrate)
201 Processing chamber 202 Processing furnace 231 Exhaust pipe 244 APC valve (valve)

Claims (2)

Supplying a source gas into a processing container containing a substrate and exhausting it from an exhaust pipe;
Supplying a reaction gas different from the source gas into the processing vessel and exhausting the exhaust gas from the exhaust pipe;
1 cycle, and performing this cycle one or more times to form a thin film with a predetermined thickness on the substrate,
In the step of supplying the source gas, immediately before supplying the source gas, a valve provided in the exhaust pipe is temporarily fully closed to temporarily close the exhaust pipe. Manufacturing method. A processing container for accommodating and processing the substrate;
A raw material gas supply system for supplying a raw material gas into the processing vessel;
A reaction gas supply system for supplying a reaction gas different from the source gas into the processing vessel;
An exhaust pipe for exhausting the inside of the processing vessel;
A valve provided in the exhaust pipe;
An exhaust device connected to the exhaust pipe;
The process of supplying the raw material gas into the processing container containing the substrate and exhausting it from the exhaust pipe, and the process of supplying the reaction gas into the processing container and exhausting from the exhaust pipe are defined as one cycle. By performing the cycle one or more times, a process for forming a thin film with a predetermined thickness on the substrate is performed, and the valve is temporarily fully closed immediately before supplying the source gas into the processing container. A substrate processing apparatus comprising: a source gas supply system, the reaction gas supply system, the valve, and a control unit that controls the exhaust device so as to temporarily close the exhaust pipe.

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