JP2012134412A - Semiconductor device manufacturing method, substrate processing method and substrate processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a nitride film having low hydrogen concentration in the film, excellent film thickness uniformity and less leakage current in a high temperature region.SOLUTION: A semiconductor device manufacturing method comprises: a step of forming a predetermined element containing layer on an oxide film by housing a substrate on which the oxide film is formed in a processing chamber under a heated pressure atmosphere of less than an atmospheric pressure and supplying a material gas; a step of changing the predetermined element containing layer to a nitride layer by supplying a nitrogen containing gas into the processing chamber under the heated pressure atmosphere of less than the atmospheric pressure; and a step of forming a nitride film on the oxide film by repeatedly performing the forming step and the changing step of the predetermined element containing layer alternately with performing a step of purging by supplying an inert gas into the processing chamber between the forming step and the changing step of the predetermined element containing layer. In the forming step of the predetermined element containing layer, an inert gas or a hydrogen containing gas is supplied via a nozzle provided lateral to the substrate when the material gas is supplied via the nozzle, and a flow rate of the material gas flowing in parallel with the substrate is set larger than a flow rate of the inert gas flowing in parallel with the substrate in the step of purging the inside of the processing chamber.

Description

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

A flash memory has an electron storage region (floating gate) surrounded by an insulating film, and writes information by exchanging electrons through a thin tunnel oxide film, and at the same time uses the insulating properties of this thin oxide film. The principle of operation is to hold electrons for a long time and keep the memory. In a flash memory, information is stored when electrons and holes (holes) accumulate in a floating gate through a tunnel insulating film at the time of writing and erasing. However, as miniaturization progresses, EOT (Equivalent Oxide Thickness) in the tunnel insulating film is stored. : Equivalent oxide thickness) is required. Therefore, a nitride film (Si ₃ N ₄ film, hereinafter also simply referred to as SiN film) having a higher dielectric constant than that of an oxide film (SiO ₂ film, hereinafter also simply referred to as SiO film) may be used as the tunnel insulating film. However, the SiN film has a high defect density, and its reduction is required. Structural defects such as dangling bonds, which are known as defects, easily bond to hydrogen, so a film with many hydrogen atoms in the film can be rephrased as a film having a high defect density, and high-quality SiN that does not contain hydrogen. There is a need for membranes.

Conventionally, the SiN film is formed by, for example, a CVD (Chemical Vapor Deposition) method using SiH ₂ Cl ₂ gas and NH ₃ gas in a temperature range of about 700 ° C. to 800 ° C., but is formed by the CVD method. Further, since SiN film (CVD-SiN film) has a high defect density and contains hydrogen in the order of 10 21, which is a quantitative value of hydrogen by TDS (thermal desorption method), these improvements are desired.

  Further, in the CVD method, it is difficult to reduce hydrogen by increasing the film formation temperature due to restrictions on film thickness uniformity and step coverage characteristics, and a film formation method replacing the CVD method is desired.

In an ALD (Atomic Layer Deposition) method, which is cited as an alternative to the CVD method, for example, in the case of ALD-SiN film formation using SiH ₂ Cl ₂ gas and NH ₃ gas, the raw material contains hydrogen. In the temperature range (about 550 ° C.), hydrogen derived from the raw material remains in the film. Therefore, film thickness uniformity and step coverage can be substituted for ALD-SiN film formation using SiH ₂ Cl ₂ gas and NH ₃ gas. A method with good characteristics is desired.

  As a result of diligent research, the inventors have devised a method of forming a nitride film having a very low hydrogen concentration and good film thickness uniformity in a high temperature region.

In such a method, a predetermined element is contained on the substrate by supplying and exhausting a raw material gas containing the predetermined element in a state where the substrate is accommodated in a heated processing container set to a pressure lower than atmospheric pressure. A step of forming a layer, and a step of changing the predetermined element-containing layer to a nitride layer by supplying and exhausting a nitrogen-containing gas into a processing vessel that is set to a pressure lower than atmospheric pressure and heated. In the meantime, a nitride film having a predetermined thickness is formed on the substrate by alternately repeating the process of supplying and exhausting an inert gas into the processing container and purging the inside of the processing container. In the process of forming the predetermined element-containing layer, the source gas is supplied from the nozzle provided on the side of the substrate toward the substrate, and at that time, the inert gas is supplied together with the source gas from the same nozzle as the nozzle. Alternatively, by supplying the hydrogen-containing gas, the flow rate of the source gas flowing in the direction parallel to the surface of the substrate is made larger than the flow rate of the inert gas flowing in the direction parallel to the surface of the substrate during the purge.

  However, the nitride film formed by the above-described method sometimes has a high leakage current despite the extremely low hydrogen concentration in the film and good film thickness uniformity.

  An object of the present invention is to provide a method for manufacturing a semiconductor device, a substrate processing method, and a substrate processing method capable of forming a nitride film with extremely low hydrogen concentration in the film, good film thickness uniformity, and low leakage current in a high temperature region. It is to provide a substrate processing apparatus.

According to one aspect of the invention,
A raw material gas containing a predetermined element is supplied into the processing container in a state where a substrate having an oxide film with a predetermined film thickness formed on the surface is accommodated in a heated processing container under a pressure atmosphere less than atmospheric pressure. Evacuating and forming a predetermined element-containing layer on the oxide film;
Supplying and exhausting a nitrogen-containing gas into the processing vessel under a heated pressure atmosphere less than atmospheric pressure to change the predetermined element-containing layer into a nitride layer;
In the meantime, a process of forming a nitride film having a predetermined thickness on the oxide film is alternately repeated with a process of supplying and exhausting an inert gas into the processing container and purging the processing container. ,
In the step of forming the predetermined element-containing layer, the source gas is supplied toward the substrate through a nozzle provided on a side of the substrate, and at that time, together with the source gas through the nozzle By supplying an inert gas or a hydrogen-containing gas toward the substrate, the flow rate of the source gas flowing in a direction parallel to the surface of the substrate is parallel to the surface of the substrate in the step of purging the inside of the processing container. A method for manufacturing a semiconductor device is provided which is larger than the flow rate of the inert gas flowing through the substrate.

According to another aspect of the invention,
A raw material gas containing a predetermined element is supplied into the processing container in a state where a substrate having an oxide film with a predetermined film thickness formed on the surface is accommodated in a heated processing container under a pressure atmosphere less than atmospheric pressure. Evacuating and forming a predetermined element-containing layer on the oxide film;
Supplying and exhausting a nitrogen-containing gas into the processing vessel under a heated pressure atmosphere less than atmospheric pressure to change the predetermined element-containing layer into a nitride layer;
In the meantime, a process of forming a nitride film having a predetermined thickness on the oxide film is alternately repeated with a process of supplying and exhausting an inert gas into the processing container and purging the processing container. ,
In the step of forming the predetermined element-containing layer, the source gas is supplied toward the substrate through a nozzle provided on a side of the substrate, and at that time, together with the source gas through the nozzle By supplying an inert gas or a hydrogen-containing gas toward the substrate, the flow rate of the source gas flowing in a direction parallel to the surface of the substrate is parallel to the surface of the substrate in the step of purging the inside of the processing container. There is provided a substrate processing method in which the flow rate of the inert gas flowing in the substrate is larger than that of the inert gas.

According to yet another aspect of the invention,
A processing container for containing a substrate;
A heater for heating the inside of the processing container;
A source gas supply system for supplying a source gas containing a predetermined element in the processing container;
A nitrogen-containing gas supply system for supplying a nitrogen-containing gas into the processing vessel;
An inert gas or hydrogen-containing gas supply system for supplying an inert gas or a hydrogen-containing gas into the processing vessel;
An exhaust system for exhausting the inside of the processing vessel;
A pressure adjusting unit for adjusting the pressure in the processing container;
The raw material gas is supplied into the processing vessel and evacuated in a state where a substrate having an oxide film with a predetermined film thickness formed on the surface is accommodated in the processing vessel under a pressure atmosphere less than atmospheric pressure. A process of forming a predetermined element-containing layer on the oxide film, and supplying and exhausting the nitrogen-containing gas into the processing vessel under a heated pressure atmosphere less than atmospheric pressure, and the predetermined element-containing layer And a process of changing the gas to a nitride layer, alternately repeating the process of supplying and exhausting the inert gas into the process vessel and purging the process vessel in the meantime, thereby forming a predetermined film on the oxide film. In the process of forming a predetermined nitride-containing layer while forming a thick nitride film, the source gas is supplied toward the substrate through a nozzle provided on the side of the substrate, and at that time, the nozzle Together with the source gas through By supplying the active gas or the hydrogen-containing gas toward the substrate, the flow rate of the source gas flowing in the direction parallel to the surface of the substrate is set in the direction parallel to the surface of the substrate in the process of purging the inside of the processing container. The heater, the raw material gas supply system, the nitrogen-containing gas supply system, the inert gas or hydrogen-containing gas supply system, the exhaust system, and the pressure adjustment unit A control unit to control;
A substrate processing apparatus is provided.

  According to the present invention, in a high-temperature region, a method for manufacturing a semiconductor device, a substrate processing method, and a method for forming a nitride film that can form a nitride film with extremely low hydrogen concentration, good film thickness uniformity, and low leakage current A substrate processing apparatus can be provided.

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. It is a figure which shows the film-forming flow in this embodiment. It is a figure which shows the timing of the gas supply in the film-forming sequence of the oxide film which concerns on this embodiment, and has shown the example which uses inert gas as deposition and adsorption inhibition gas. It is a figure which shows the timing of the gas supply in the film-forming sequence of the oxide film which concerns on this embodiment, and has shown the example using hydrogen-containing gas as deposition and adsorption | suction inhibition gas. It is a figure which shows the timing of the gas supply in the film-forming sequence of the nitride film which concerns on this embodiment, and has shown the example using inert gas as deposition and adsorption | suction inhibition gas. It is a figure which shows the timing of the gas supply in the film-forming sequence of the nitride film which concerns on this embodiment, and has shown the example using hydrogen-containing gas as deposition / adsorption inhibition gas. It is a graph which shows the leakage current density and EOT of the SiN film (Example) formed through the SiO film and the SiO film (reference example) formed by wet oxidation, respectively. It is a graph which respectively shows the leakage current density and EOT of the SiN film (comparative example) formed directly on the wafer without passing through the SiO film, and the SiO film (reference example) formed by wet oxidation. It is a figure which shows typically the mode of silicon deposition or adsorption | suction of HCD gas, (a) shows the case where the flow velocity of HCD gas is small, and (b) shows the case where the flow velocity of HCD gas is large, respectively. It is sectional drawing which shows a mode that the silicon oxide film and the silicon nitride film were laminated | stacked in order on the wafer by the film-forming sequence concerning this embodiment.

The inventors diligently studied the above-described factors for increasing the leakage current of the nitride film. As a result, when the deposition temperature of the nitride film is increased, the temperature rise time and the temperature stabilization time become longer, and the influence on the interface between the substrate surface and the nitride film due to adsorbed oxygen or entrained oxygen on the substrate surface increases. Has been found to be a factor in this phenomenon. In addition, by increasing the temperature of the nitride film, damage such as etch pits due to thermal etching may occur on the substrate surface, increasing the effective surface area of the substrate, which affects the electrical properties of the nitride film. It was also found that this is one factor that gives In addition, the conventional thermal oxide film formed by oxidation of the substrate surface (base material oxidation) has good characteristics because the interface between the substrate and the thermal oxide film is constantly updated, but nitride is deposited on the substrate. Since the interface between the substrate and the nitride film is not updated, damage such as etch pits remains as it is, and this interface characteristic becomes a factor that affects the electrical characteristics of the nitride film. I also investigated.

  The inventors have found that the above-described problem can be solved by forming the nitride film through an oxide film having a predetermined thickness instead of directly forming the nitride film on the substrate. That is, a raw material gas containing a predetermined element is supplied into a processing container in a state where a substrate having an oxide film of a predetermined thickness formed on the surface is accommodated in a heated processing container under a pressure atmosphere below atmospheric pressure. And evacuating to form a predetermined element-containing layer on the oxide film, and supplying and exhausting a nitrogen-containing gas into a heated processing vessel under a pressure atmosphere less than atmospheric pressure to form the predetermined element-containing layer. The step of changing to a nitride layer is alternately repeated with the step of supplying and exhausting an inert gas into the processing vessel and purging the inside of the processing vessel therebetween, thereby forming a nitride film having a predetermined thickness on the oxide film. When forming, in the step of forming the predetermined element-containing layer, the source gas is supplied toward the substrate through a nozzle provided on the side of the substrate, and at that time, together with the source gas through the nozzle Inert gas or hydrogen-containing gas toward the substrate By feeding, the flow rate of the source gas flowing parallel to the surface direction of the substrate, is greater than the flow rate of the inert gas flowing parallel to the surface direction of the substrate in the step of purging the process container. As a result, it has been found that in a high temperature region, it is possible to form a nitride film in which the hydrogen concentration in the film is extremely low, the film thickness uniformity is good, and the leakage current is small.

  Even if the film formation temperature of the nitride film is increased by pre-forming an oxide film as the base film of the nitride film, the influence of adsorbed oxygen and entrained oxygen on the substrate surface on the interface between the substrate surface and the nitride film Can be reduced. In addition, since the surface of the substrate is covered with an oxide film, even if the deposition temperature of the nitride film is increased, the generation of etch pits on the substrate surface due to thermal etching can be suppressed, and the effective surface area of the substrate surface can be reduced. Increase can be prevented. As a result, the influence of the nitride film on the electrical characteristics can be reduced, and the leakage current of the nitride film can be reduced. Note that the oxide film as the base film may be formed by depositing an oxide film on the substrate, or may be formed by thermally oxidizing the surface of the substrate. The thickness of the oxide film is preferably in the range of 2 nm to 4 nm, for example, 2 nm. The formation of the oxide film and the nitride film may be performed continuously in the same processing container (in-situ) or separately in different processing containers.

  Note that the step of forming the predetermined element-containing layer on the oxide film is performed under conditions where a CVD reaction occurs. At this time, a predetermined element layer as a predetermined element-containing layer having a thickness of less than one atomic layer to several atomic layers is formed on the oxide film. The predetermined element-containing layer may be an adsorption layer of a source gas containing a predetermined element (hereinafter also simply referred to as source gas). Here, the predetermined element layer is a generic name including a continuous layer composed of a predetermined element, a discontinuous layer, and a thin film formed by overlapping these layers. In addition, the continuous layer comprised with a predetermined element may be called a thin film. The source gas adsorption layer includes a discontinuous chemical adsorption layer in addition to a continuous chemical adsorption layer of gas molecules of the source gas. In addition, the layer less than 1 atomic layer means the atomic layer formed discontinuously. Under the condition that the source gas self-decomposes, the predetermined element layer is formed by depositing the predetermined element on the oxide film. Under conditions where the source gas does not self-decompose, the source gas is adsorbed on the oxide film, thereby forming an adsorption layer of the source gas. Note that it is preferable to form the predetermined element layer because the deposition rate can be increased, rather than forming the source gas adsorption layer on the oxide film.

Further, in the step of changing the predetermined element-containing layer into a nitride layer, a nitrogen-containing gas is generated by activating or thermally decomposing a nitrogen-containing gas in a processing container under a pressure atmosphere lower than atmospheric pressure. The predetermined element-containing layer is nitrided by this nitriding species to be changed (modified) into a nitride layer. That is, the nitriding species and the predetermined element-containing layer are reacted to change the predetermined element-containing layer into a nitride layer. The step of changing the predetermined element-containing layer into the nitride layer can be performed in a non-plasma reduced pressure atmosphere. In the step of changing the predetermined element-containing layer to the nitride layer, a nitrogen-containing gas can be activated with plasma and used.

  Then, in the step of forming the predetermined element-containing layer, the source gas is supplied from the nozzle provided on the side of the substrate toward the substrate, and at that time, the inert gas together with the source gas is supplied from the same nozzle as the nozzle. Alternatively, by supplying the hydrogen-containing gas, the flow rate of the source gas flowing in the direction parallel to the surface of the substrate is made larger than the flow rate of the inert gas flowing in the direction parallel to the surface of the substrate during the purge. Thus, by increasing the flow rate of the source gas flowing in the direction parallel to the surface of the substrate, the predetermined element-containing layer is formed on the substrate while inhibiting (suppressing) the deposition or adsorption of the predetermined element-containing layer on the oxide film. It becomes possible to move the deposition or adsorption center of the predetermined element-containing layer from the edge side of the substrate to the center. As a result, it is possible to form a nitride film with good film thickness uniformity in the high temperature region.

  The present invention has been made based on such knowledge obtained by the inventors. Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

<One Embodiment of the Present Invention>
(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. 2 is a schematic configuration diagram of a vertical processing furnace suitably used in the present embodiment, and the processing furnace 202 portion is shown by a cross-sectional view taken along line AA in FIG. The present invention is not limited to the substrate processing apparatus according to the present embodiment, and can be suitably applied to a substrate processing apparatus having a single wafer type, hot wall type, or cold wall type processing furnace.

  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.

  In the processing chamber 201, a first nozzle 233 a as a first gas introduction unit and a second nozzle 233 b as a second gas introduction unit are provided so as to penetrate the lower side wall of the reaction tube 203. A first gas supply pipe 232a is connected to the first nozzle 233a. In addition, a second gas supply pipe 232b, a third gas supply pipe 232c, and a fourth gas supply pipe 232d are connected to the second nozzle 233b. As described above, the reaction tube 203 is provided with the two nozzles 233a and 233b and the four gas supply tubes 232a, 232b, 232c, and 232d. It is comprised so that gas can be supplied.

In the first gas supply pipe 232a, 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 are provided 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 233a is connected to the tip of the first gas supply pipe 232a. The first nozzle 233a 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. That is, the first nozzle 233a is provided on the side of the wafer arrangement area where the wafers 200 are arranged. The first nozzle 233a is configured as an L-shaped long nozzle. A gas supply hole 248a for supplying gas is provided on the side surface of the first nozzle 233a. The gas supply hole 248 a is opened so as to face the center of the reaction tube 203, and gas can be supplied toward the wafer 200. A plurality of gas supply holes 248a 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 first gas supply system is mainly configured by the first gas supply pipe 232a, the mass flow controller 241a, and the valve 243a. The first nozzle 233a may be included in the first gas supply system. 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 first inert gas supply system also functions as a purge gas supply system.

  In the second gas supply pipe 232b, 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 are provided 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 233b is connected to the tip of the second gas supply pipe 232b. The second nozzle 233b is provided in a buffer chamber 237 that is a gas dispersion space.

  The buffer chamber 237 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 part to the upper part of the inner wall of the reaction tube 203 along the loading direction of the wafer 200. That is, the buffer chamber 237 is provided on the side of the wafer arrangement region. A gas supply hole 248 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 248 c is opened so as to face the center of the reaction tube 203, and gas can be supplied toward the wafer 200. A plurality of gas supply holes 248c 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 233b is located at the end of the buffer chamber 237 opposite to the end where the gas supply hole 248c 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. It is provided to stand up. That is, the second nozzle 233b is provided on the side of the wafer arrangement region. The second nozzle 233b is configured as an L-shaped long nozzle. A gas supply hole 248b for supplying gas is provided on the side surface of the second nozzle 233b. The gas supply hole 248 b is opened to face the center of the buffer chamber 237. A plurality of gas supply holes 248 b are provided from the lower part to the upper part of the reaction tube 203, similarly to the gas supply holes 248 c of the buffer chamber 237. Each of the plurality of gas supply holes 248b 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 the present embodiment, by adjusting the opening area and the opening pitch of the gas supply holes 248b of the second nozzle 233b from the upstream side to the downstream side as described above, first, from each of the gas supply holes 248b, Although there is a difference in flow velocity, gas with the same flow rate is ejected. The gas ejected from each of the gas supply holes 248b 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 jetted into the buffer chamber 237 from each of the gas supply holes 248b of the second nozzle 233b is reduced in the particle velocity of each gas in the buffer chamber 237, and then is processed from the gas supply hole 248c of the buffer chamber 237. It spouts into 201. Accordingly, when the gas ejected into the buffer chamber 237 from each of the gas supply holes 248b of the second nozzle 233b is ejected into the processing chamber 201 from each of the gas supply holes 248c of the buffer chamber 237, a uniform flow rate is obtained. And a gas having a flow rate.

  A second gas supply system is mainly configured by the second gas supply pipe 232b, the mass flow controller 241b, and the valve 243b. Note that the second nozzle 233b and the buffer chamber 237 may be included in the second gas supply system. 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 second inert gas supply system also functions as a purge gas supply system.

  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 tip of the third gas supply pipe 232c is connected to the downstream side of the valve 243b of the second gas supply pipe 232b.

  A third gas supply system is mainly configured by the third gas supply pipe 232c, the mass flow controller 241c, and the valve 243c. The second gas supply pipe 232b may be considered to include the second nozzle 233b and the buffer chamber 237 in the third gas supply system on the downstream side of the connection portion between the second gas supply pipe 232b and the third gas supply pipe 232c. 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 third inert gas supply system also functions as a purge gas supply system.

  In the fourth gas supply pipe 232d, 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 are provided 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 tip of the fourth gas supply pipe 232d is connected to the downstream side of the valve 243b of the second gas supply pipe 232b.

  A fourth gas supply system is mainly configured by the fourth gas supply pipe 232d, the mass flow controller 241d, and the valve 243d. The second gas supply pipe 232b may be considered to include the second nozzle 233b and the buffer chamber 237 in the fourth gas supply system on the downstream side of the connection portion between the second gas supply pipe 232b and the fourth gas supply pipe 232d. 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. The fourth inert gas supply system also functions as a purge gas supply system.

From the first gas supply pipe 232a, for example, hexachlorodisilane (Si ₂ Cl ₆ , abbreviation: HCD) is used as a source gas containing a predetermined element, that is, a source gas containing silicon (Si) as a predetermined element (silicon-containing gas). A gas is supplied into the processing chamber 201 via the mass flow controller 241a, the valve 243a, and the first nozzle 233a. That is, the first gas supply system is configured as a source gas supply system (silicon-containing gas supply system). In addition, when using the liquid raw material which is a liquid state under normal temperature normal pressure like HCD, a liquid raw material will be vaporized with vaporization systems, such as a vaporizer and a bubbler, and will be supplied as raw material gas. At the same time, an inert gas as a deposition / adsorption inhibition gas is supplied from the first inert gas supply pipe 232e into the first gas supply pipe 232a via the mass flow controller 241e and the valve 243e. Here, the deposition / adsorption inhibition gas is a gas for inhibiting the deposition of silicon on the surface of the wafer 200 or the adsorption of the HCD gas. The inert gas as the deposition / adsorption inhibition gas supplied into the first gas supply pipe 232a is supplied into the processing chamber 201 together with the HCD gas through the first nozzle 233a. At this time, as the deposition / adsorption inhibition gas, a hydrogen-containing gas may be supplied into the first gas supply pipe 232a instead of the inert gas. In this case, the first inert gas supply system may be replaced with a hydrogen-containing gas supply system. That is, in this case, the hydrogen-containing gas supply system includes the hydrogen-containing gas supply pipe 232e, the mass flow controller 241e, and the valve 243e. Thus, the first inert gas supply system is also configured as a deposition / adsorption inhibition gas supply system and can be replaced with a hydrogen-containing gas supply system.

From the second gas supply pipe 232b, for example, ammonia (NH ₃ ) gas is contained as nitrogen-containing gas (nitrogen-containing gas) via the mass flow controller 241b, the valve 243b, the second nozzle 233b, and the buffer chamber 237. Supplied in. That is, the second gas supply system is configured as a nitrogen-containing gas supply system. At the same time, the inert gas may be supplied from the second inert gas supply pipe 232f into the second gas supply pipe 232b via the mass flow controller 241f and the valve 243f.

From the third gas supply pipe 232c, as a gas containing oxygen (oxygen-containing gas), for example, oxygen (O ₂ ) gas includes a mass flow controller 241c, a valve 243c, a second gas supply pipe 232b, a second nozzle 233b, and a buffer chamber. 237 is supplied into the processing chamber 201. That is, the third gas supply system is configured as an oxygen-containing gas supply system. At the same time, the inert gas may be supplied from the third inert gas supply pipe 232g into the third gas supply pipe 232c via the mass flow controller 241g and the valve 243g.

From the fourth gas supply pipe 232d, for example, hydrogen (H ₂ ) gas as a gas containing hydrogen (hydrogen-containing gas) includes a mass flow controller 241d, a valve 243d, a second gas supply pipe 232b, a second nozzle 233b, and a buffer chamber. 237 is supplied into the processing chamber 201. That is, the fourth gas supply system is configured as a hydrogen-containing gas supply system. At the same time, the inert gas may be supplied from the fourth inert gas supply pipe 232h into the fourth gas supply pipe 232d via the mass flow controller 241h and the valve 243h.

In the present embodiment, NH ₃ gas, O ₂ gas, and H ₂ gas are supplied from the same nozzle into the processing chamber 201 (inside the buffer chamber 237). The gas may be supplied into 201, or only H ₂ gas may be supplied into the processing chamber 201 from another nozzle. However, sharing the nozzles with a plurality of types of gas has the advantages that the number of nozzles can be reduced, the apparatus cost can be reduced, and maintenance is facilitated. Further, H ₂ gas and HCD gas may be supplied into the processing chamber 201 from the same nozzle. The deposition temperature range described later, but do not react with _{H 2} gas and HCD gas, NH ₃ gas and HCD gas, and since the _{O 2} gas and the HCD gas is considered to react respectively, NH ₃ gas and O It is better to separate the nozzle for supplying the _two gases and the nozzle for supplying the HCD gas.

  In the buffer chamber 237, as shown in FIG. 2, a first rod-shaped electrode 269 that is a first electrode having an elongated structure and a second rod-shaped electrode 270 that is a second electrode are provided at the bottom of the reaction tube 203. The upper part is disposed along the stacking direction of the wafers 200. Each of the first rod-shaped electrode 269 and the second rod-shaped electrode 270 is provided in parallel with the second nozzle 233b. Each of the first rod-shaped electrode 269 and the second rod-shaped electrode 270 is protected by being covered with an electrode protection tube 275 that is a protection tube that protects each electrode from the top to the bottom. 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. It 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 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 through 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 246 as an exhaust device is connected. The APC valve 244 is an open / close valve configured to open and close the valve to stop evacuation / stop of evacuation in the processing chamber 201 and further adjust the pressure by adjusting the valve opening. By adjusting the opening degree of the APC valve 244 based on the pressure information detected by the pressure sensor 245 while operating the vacuum pump 246, the pressure in the processing chamber 201 becomes a predetermined pressure (degree of vacuum). It is configured so that it can be evacuated. An exhaust system is mainly configured by the exhaust pipe 231, the APC valve 244, the vacuum pump 246, and the pressure sensor 245.

  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 configured to contact 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. On the opposite side of the seal cap 219 from the processing chamber 201, a rotation mechanism 267 for rotating a boat 217 as a substrate holder described later is installed. A rotation shaft 255 of the rotation mechanism 267 passes through the seal cap 219 and is connected to the boat 217. The rotation mechanism 267 is configured to rotate the wafer 200 by rotating the boat 217. The seal cap 219 is configured to be lifted and lowered in the vertical direction by a boat elevator 115 as a lifting mechanism vertically installed outside the reaction tube 203. The boat elevator 115 is configured such that the boat 217 can be carried into and out of the processing chamber 201 by moving the seal cap 219 up and down.

  The boat 217 as a substrate support is made of a heat-resistant material such as quartz or silicon carbide, and supports 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. It is configured. 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 the heat insulating plates 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. Similar to the first nozzle 233 a and the second nozzle 233 b, the temperature sensor 263 is configured in an L shape 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 a pressure sensor 245. , APC valve 244, vacuum pump 246, heater 207, temperature sensor 263, rotating mechanism 267, boat elevator 115, high frequency power supply 273, matching device 272, and the like. The controller 121 controls the flow rates 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 The opening and closing of the valve 244 and the pressure adjustment operation based on the pressure sensor 245, the temperature adjustment operation of the heater 207 based on the temperature sensor 263, the start / stop of the vacuum pump 246, the rotation speed adjustment operation of the rotation mechanism 267, and the boat 217 by the boat elevator 115 Control such as lifting and lowering, power supply control of the high frequency power supply 273, and impedance control by the matching unit 272 are performed.

(2) Substrate Processing Step Next, after forming an oxide film with a predetermined thickness on the substrate as a base film as one step of the manufacturing process of the semiconductor device (device) using the processing furnace of the substrate processing apparatus described above. An example of a method for forming a nitride film on an oxide film as a base film will be described. In the following description, the operation of each part constituting the substrate processing apparatus is controlled by the controller 121.

  FIG. 3 shows a flow chart of film formation in the present embodiment, FIGS. 4 and 5 show timing diagrams of gas supply in the film formation sequence of the oxide film according to the present embodiment, and FIGS. 6 and 7 show nitridation according to the present embodiment. The timing chart of the gas supply in the film formation sequence is shown respectively.

  In the film forming sequence of the present embodiment, first, a source gas containing silicon as a predetermined element is supplied and exhausted in a state where a substrate is accommodated in a heated processing container under a pressure atmosphere less than atmospheric pressure. A step of forming a silicon-containing layer as a predetermined element-containing layer on the substrate, and supplying and exhausting an oxygen-containing gas and a hydrogen-containing gas into a processing vessel under a heated pressure atmosphere less than atmospheric pressure, The step of changing the silicon-containing layer into a silicon oxide layer as an oxide layer is alternately repeated with a step of supplying and exhausting an inert gas into the processing container and purging the processing container in between. A silicon oxide film is formed as an oxide film having a predetermined thickness.

Then, a raw material gas containing silicon as a predetermined element is supplied in a state where a substrate having a silicon oxide film having a predetermined thickness formed on the surface thereof is housed in a heated processing vessel under a pressure atmosphere less than atmospheric pressure. And evacuating and supplying a nitrogen-containing gas into a processing container under a heated pressure atmosphere less than atmospheric pressure and exhausting the silicon-containing layer as a predetermined element-containing layer on the silicon oxide film. And the step of changing the silicon-containing layer into a silicon nitride layer as a nitride layer, and alternately repeating a process of supplying and exhausting an inert gas into the processing container and purging the processing container in between. A silicon nitride film as a nitride film having a predetermined thickness is formed on the oxide film.

  In the step of forming each silicon-containing layer, which is performed when forming the silicon oxide film and forming the silicon nitride film, the source gas is directed toward the substrate through a nozzle provided on the side of the substrate. The raw material flowing in a direction parallel to the surface of the substrate by supplying an inert gas or hydrogen-containing gas as a deposition / adsorption inhibition gas to the substrate together with the source gas through the nozzle. The gas flow rate is set higher than the flow rate of the inert gas flowing in the direction parallel to the surface of the substrate in the process of purging the inside of the processing container.

This will be specifically described below. In this embodiment, first, HCD gas is used as a source gas, O ₂ gas is used as an oxygen-containing gas, H ₂ gas is used as a hydrogen-containing gas, N ₂ gas or H ₂ gas is used as a deposition / adsorption inhibition gas, and purge gas is used. N ₂ gas is used, and a silicon oxide film (SiO ₂ film, hereinafter, also simply referred to as SiO film) is formed on the wafer 200 by the film formation flow shown in FIG. 3 and the film formation sequence shown in FIGS. Thereafter, the HCD gas as a source gas, NH ₃ gas as the nitrogen-containing gas, _{N 2} gas or _{H 2} gas as the deposition and absorption inhibiting gas, a _{N 2} gas as a purge gas, film-forming flow of FIG. 3, FIG. 6 7, a silicon nitride film (Si ₃ N ₄ film, hereinafter also simply referred to as an SiN film) is formed on the silicon oxide film as the base film.

(Wafer charge and boat load)
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.

(Pressure adjustment and temperature adjustment)
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 rotation mechanism 267 starts to rotate the boat 217 and the wafer 200.

(Silicon oxide film formation process)
Thereafter, the following steps 1a to 4a are set as one cycle, and this cycle is performed a predetermined number of times to form a silicon oxide film having a predetermined thickness on the wafer 200.

[Step 1a]
The valve 243a of the first gas supply pipe 232a and the valve 243e of the first inert gas supply pipe 232e are opened, the HCD gas is used as the first gas supply pipe 232a, and the deposition / adsorption inhibition gas is used as the first inert gas supply pipe 232e. Flow N ₂ gas. N ₂ gas flows from the first inert gas supply pipe 232e, and the flow rate is adjusted by the mass flow controller 241e. The HCD gas flows from the first gas supply pipe 232a and the flow rate is adjusted by the mass flow controller 241a. The flow-adjusted HCD gas is mixed with the flow-adjusted N ₂ gas in the first gas supply pipe 232a, and is heated from the gas supply hole 248a of the first nozzle 233a into the heated processing chamber 201 in a reduced pressure state. Supplied and exhausted from the exhaust pipe 231 (HCD gas + N ₂ gas supply).

At this time, the APC valve 244 is appropriately adjusted to maintain the pressure in the processing chamber 201 at a pressure lower than atmospheric pressure, for example, in a range of 10 to 1000 Pa. The supply flow rate of the HCD gas controlled by the mass flow controller 241a is, for example, a flow rate in the range of 20 to 1000 sccm (0.02 to 1 slm). The supply flow rate of N ₂ gas as the deposition / adsorption inhibition gas controlled by the mass flow controller 241e is larger than the supply flow rate of the HCD gas, for example, a flow rate in the range of 1000 to 20000 sccm (1 to 20 slm). The time for exposing the HCD gas to the wafer 200 is, for example, a time within a range of 1 to 120 seconds. The temperature of the heater 207 is set so that the CVD reaction occurs in the processing chamber 201 in the above-described pressure zone. That is, the temperature of the heater 207 is set so that the temperature of the wafer 200 is, for example, in the range of 350 to 950 ° C., preferably 700 to 800 ° C. Note that when the temperature of the wafer 200 is less than 350 ° C., the HCD is difficult to be decomposed and adsorbed on the wafer 200. When the temperature of the wafer 200 exceeds 950 ° C., the CVD reaction becomes too strong, the action of the deposition / adsorption inhibition gas does not work sufficiently, and it becomes difficult to improve the deterioration of the film thickness uniformity. On the other hand, when the temperature of the wafer 200 is lower than 700 ° C., the film thickness uniformity is relatively good, and the film thickness uniformity is significantly deteriorated in a high temperature region of 700 ° C. or higher. Especially effective. Further, when the temperature of the wafer 200 exceeds 800 ° C., the CVD reaction becomes strong, and in order to improve the deterioration of the film thickness uniformity, it is necessary to increase the flow rate of the deposition / adsorption inhibition gas. Gas consumption increases and costs increase. In addition, there is a demerit that the film forming speed is lowered. For example, the deposition rate when the temperature of the wafer 200 is 900 ° C. is approximately one third of the deposition rate when the temperature of the wafer 200 is 700 to 800 ° C. In view of the above, the temperature of the wafer 200 is preferably 350 to 950 ° C., more preferably 700 to 800 ° C.

  By supplying the HCD gas into the processing chamber 201 under the above-described conditions, that is, the conditions in which the CVD reaction occurs, the silicon-containing layer of less than one atomic layer to several atomic layers is formed on the wafer 200 (surface underlayer film). A silicon layer is formed. The silicon-containing layer may be an HCD gas adsorption layer. Here, the silicon layer is a generic name including a continuous layer made of silicon, a discontinuous layer, and a silicon thin film formed by overlapping these layers. A continuous layer made of silicon may be referred to as a silicon thin film. The HCD gas adsorption layer includes a discontinuous chemical adsorption layer as well as a continuous chemical adsorption layer of gas molecules of the HCD gas. In addition, the layer less than 1 atomic layer means the atomic layer formed discontinuously. Under the condition that the HCD gas self-decomposes, silicon is deposited on the wafer 200 to form a silicon layer. Under conditions where the HCD gas does not self-decompose, the HCD gas is adsorbed on the wafer 200 to form an HCD gas adsorption layer. When the thickness of the silicon-containing layer formed on the wafer 200 exceeds several atomic layers, the oxidizing action in step 3a 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 set to be less than one atomic layer to several atomic layers. Note that it is preferable to form a silicon layer on the wafer 200 in order to increase the deposition rate, rather than forming an HCD gas adsorption layer on the wafer 200.

At this time, as described above, the N ₂ gas as the deposition / adsorption inhibition gas is supplied toward the wafer 200 at a large flow rate together with the HCD gas from the same nozzle as the first nozzle 233a that supplies the HCD gas. The flow rate of the HCD gas, particularly the flow rate of the HCD gas flowing in a direction parallel to the surface of the wafer 200 (crossing the surface of the wafer 200) is increased. That is, the HCD gas is strongly blown in the direction parallel to the surface of the wafer 200. Thereby, the deposition efficiency of silicon on the wafer 200 or the adsorption efficiency of the HCD gas can be lowered, and the silicon-containing layer can be formed on the wafer 200 while suppressing the deposition or adsorption. By the action of the deposition / adsorption inhibition gas, the deposition or adsorption center of the silicon-containing layer can be moved from the edge side of the wafer 200 to the center as shown in FIG. And the thinnest part can be reduced. For example, even in a region where the adsorption reaction breaks down in a high temperature region of 700 ° C. or higher, that is, in a region where deposition or adsorption of the silicon-containing layer is excessive, the silicon-containing layer can be uniformly formed. It becomes possible to form.

FIG. 10A is a diagram schematically showing the state of silicon deposition or HCD gas adsorption when the flow rate of the HCD gas flowing parallel to the surface of the wafer 200 is small. FIG. 10B is a diagram schematically showing the state of silicon deposition or HCD gas adsorption when the flow rate of the HCD gas flowing in the direction parallel to the surface of the wafer 200 is large. The white arrows in FIG. 10 indicate the flow directions of the HCD gas and the N ₂ gas, and the white circles (◯) on the wafer 200 are adsorbed on the Si atoms deposited on the wafer 200 or on the wafer 200. HCD gas molecules are shown. In FIG. 10, only the left half of the wafer 200 is shown for convenience.

  As shown in FIG. 10, by increasing the flow rate of the HCD gas flowing in the direction parallel to the surface of the wafer 200, the thickness of the silicon-containing layer is reduced as a whole, and the deposition or adsorption center of the silicon-containing layer is set at the wafer 200. It is possible to move from the edge side to the center. Further, the difference between the thickest portion and the thinnest portion of the silicon-containing layer can be reduced, and the silicon-containing layer can be formed uniformly over the surface of the wafer 200.

Note that the supply flow rate of the N ₂ gas as the deposition / adsorption inhibition gas is preferably set to a flow rate in the range of 1 to 20 slm as described above, and is preferably larger than the supply flow rate of the HCD gas. In this way, the supply flow rate of N ₂ gas is set, and the volume flow rate of N ₂ gas is set to be larger than the volume flow rate of HCD gas. Make it faster than flowing the gas alone. That is, the HCD gas is blown stronger in the direction parallel to the surface of the wafer 200 than when the HCD gas is supplied alone. The supply flow rate of N ₂ gas as the deposition / adsorption inhibition gas is preferably larger than the supply flow rate of O ₂ gas or H ₂ gas supplied into the processing chamber 201 in step 3a described later. In this way, the supply flow rate of N ₂ gas is set, and the volume flow rate of N ₂ gas is set larger than the volume flow rate of O ₂ gas or H ₂ gas, so that the HCD gas flowing in the direction parallel to the surface of the wafer 200 is obtained. Is made faster than the flow rate of O ₂ gas and H ₂ gas flowing in the direction parallel to the surface of the wafer 200. That is, the HCD gas is blown in the direction parallel to the surface of the wafer 200 stronger than the O ₂ gas or H ₂ gas is blown in the direction parallel to the surface of the wafer 200. Furthermore, the supply flow rate of N ₂ gas as the deposition / adsorption inhibition gas is preferably larger than the supply flow rate of N ₂ gas as the purge gas supplied into the processing chamber 201 in steps 2a and 4a described later. . In this way, the supply flow rate of N ₂ gas as the deposition / adsorption inhibition gas is set, and the volume flow rate of N ₂ gas as the deposition / adsorption inhibition gas is set larger than the volume flow rate of N ₂ gas as the purge gas. Thus, the flow rate of the HCD gas flowing in the direction parallel to the surface of the wafer 200 is made faster than the flow rate of the N ₂ gas as the purge gas flowing in the direction parallel to the surface of the wafer 200. That is, it is stronger than spraying N ₂ gas as a purge gas in the direction parallel to the surface of the wafer 200, and HCD gas is sprayed in the direction parallel to the surface of the wafer 200.

Specifically, the volume flow rate of the N ₂ gas as the deposition / adsorption inhibition gas is about 10 to 30 times the volume flow rate of the HCD gas and about 5 to 30 times the volume flow rate of the N ₂ gas as the purge gas. Is preferable. By setting the volume flow rate of N ₂ gas as the deposition / adsorption inhibition gas to about 10 to 30 times the volume flow rate of HCD gas, the flow rate of HCD gas flowing in the direction parallel to the surface of the wafer 200 can be increased sufficiently. Thus, deposition or adsorption of the silicon-containing layer can be more sufficiently suppressed, and the deposition or adsorption center can be easily set from the edge side of the wafer 200 to the center. It is also easy to reduce the difference between the thickest part and the thinnest part of the silicon-containing layer. As a result, the film thickness uniformity can be more sufficiently improved. Further, it is possible to prevent the practical flow rate from being obtained because the flow rate of the HCD gas becomes too high and the deposition or adsorption of the silicon-containing layer is suppressed too much.

As raw materials containing Si, not only inorganic raw materials such as TCS (tetrachlorosilane, SiCl ₄ ), DCS (dichlorosilane, SiH ₂ Cl ₂ ), SiH ₄ (monosilane), but also aminosilane-based 4DMAS (tetrakis) are included. Dimethylaminosilane, Si [N (CH ₃ ) ₂ ] ₄ ), 3DMAS (trisdimethylaminosilane, Si [N (CH ₃ ) ₂ ] ₃ H), 2DEAS (bisdiethylaminosilane, Si [N (C ₂ H ₅ ) ₂ ] ₂ H ₂ ), BTBAS (Bisturary butylaminosilane, SiH ₂ [NH (C ₄ H ₉ )] ₂ ) or the like may be used.

As the inert gas as the deposition / adsorption inhibition gas, a rare gas such as Ar, He, Ne, or Xe may be used in addition to the N ₂ gas. Further, a hydrogen-containing gas may be used as the deposition / adsorption inhibition gas. As the hydrogen-containing gas, for example, hydrogen (H ₂ ) gas, deuterium (D ₂ ) gas, or the like can be used. FIG. 5 shows an example of a film forming sequence using H ₂ gas, which is a hydrogen-containing gas, as the deposition / adsorption inhibition gas. The supply flow rate of H ₂ gas as the deposition / adsorption inhibition gas is set to a flow rate in the range of 1000 to 20000 sccm (1 to 20 slm), similarly to the supply flow rate of N ₂ gas as the deposition / adsorption inhibition gas. As the deposition / adsorption inhibition gas, silicon formed by using a rare gas such as Ar or He, or a hydrogen-containing gas such as H ₂ gas or D ₂ gas, which is a gas not containing nitrogen (N). There is also an effect that the N impurity concentration in the oxide film can be reduced.

[Step 2a]
After the silicon-containing layer is formed on the wafer 200, the valve 243a of the first gas supply pipe 232a 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 inside of the processing chamber 201 is evacuated by the vacuum pump 246, and the remaining HCD gas is removed from the processing chamber 201. At this time, the valve 243e remains open and the supply of N ₂ gas as an inert gas into the processing chamber 201 is maintained. At this time, the valves 243f, 243g, and 243h may be opened. The N ₂ gas acts as a purge gas, which can further enhance the effect of removing the unreacted HCD gas remaining in the processing chamber 201 or the silicon-containing layer formation from the processing chamber 201 (residual) Gas removal).

At this time, the temperature of the heater 207 is set so that the temperature of the wafer 200 is in the range of 350 to 950 ° C., preferably 700 to 800 ° C., as in the case of supplying the HCD gas. The supply flow rate of N ₂ gas as the purge gas is set to a flow rate in the range of 200 to 1000 sccm (0.2 to 1 slm). Note that the volume flow rate of the N ₂ gas as the purge gas does not need to be as large as the volume flow rate of the N ₂ gas as the deposition / adsorption inhibition gas, and a sufficient purge effect can be obtained with a smaller flow rate. In other words, the volume flow rate of N ₂ gas as the deposition / adsorption inhibition gas needs to be larger than the volume flow rate of N ₂ gas as the purge gas. That is, in order to obtain the deposition / adsorption suppression effect of the silicon-containing layer, the volume flow rate of the N ₂ gas as the deposition / adsorption inhibition gas is set to be larger than the volume flow rate of the N ₂ gas sufficient to obtain the purge effect. There is a need to. Therefore, when removing the residual gas in the processing chamber 201 by purging, the mass flow controller 241e is controlled, and the supply flow rate of N ₂ gas supplied from the first inert gas supply pipe 232e is changed from 1 to 20 slm to 0.2. It will be changed to ˜1 slm and the volume flow rate of N ₂ gas will be reduced. In addition to the N ₂ gas, a rare gas such as Ar, He, Ne, or Xe may be used as the purge gas.

[Step 3a]
After the residual gas in the processing chamber 201 is removed, the valve 243c of the third gas supply pipe 232c is opened, and O ₂ gas is allowed to flow through the third gas supply pipe 232c. The O ₂ gas flows from the third gas supply pipe 232c, and the flow rate is adjusted by the mass flow controller 241c. The O ₂ gas whose flow rate has been adjusted is supplied from the gas supply hole 248b of the second nozzle 233b to the heated buffer chamber 237 via the second gas supply pipe 232b. At the same time, the valve 243d of the fourth gas supply pipe 232d is opened, and H ₂ gas is caused to flow through the fourth gas supply pipe 232d. The H ₂ gas flows from the fourth gas supply pipe 232d and the flow rate is adjusted by the mass flow controller 241d. The H ₂ gas whose flow rate has been adjusted is supplied to the heated buffer chamber 237 from the gas supply hole 248b of the second nozzle 233b through the second gas supply pipe 232b. The H ₂ gas is mixed with O ₂ gas in the second gas supply pipe 232b when passing through the second gas supply pipe 232b. That is, a mixed gas of O ₂ gas and H ₂ gas is supplied from the second nozzle 233b. The mixed gas of O ₂ gas and H ₂ gas supplied into the buffer chamber 237 is supplied from the gas supply hole 248 c of the buffer chamber 237 into the heated processing chamber 201 in a reduced pressure state and exhausted from the exhaust pipe 231. (O ₂ gas + H ₂ gas supply).

At this time, the valve 243g of the third inert gas supply pipe 232g may be opened to supply N ₂ gas as an inert gas from the third inert gas supply pipe 232g. The flow rate of the N ₂ gas is adjusted by the mass flow controller 241g and is supplied into the third gas supply pipe 232c. Further, the valve 243h of the fourth inert gas supply pipe 232h may be opened, and N ₂ gas may be supplied as an inert gas from the fourth inert gas supply pipe 232h. The flow rate of the N ₂ gas is adjusted by the mass flow controller 241h, and the N ₂ gas is supplied into the fourth gas supply pipe 232d. In this case, a mixed gas of O ₂ gas, H ₂ gas, and N ₂ gas is supplied from the second nozzle 233b. As the inert gas, a rare gas such as Ar, He, Ne, or Xe may be used in addition to the N ₂ gas.

At this time, the APC valve 244 is appropriately adjusted to maintain the pressure in the processing chamber 201 at a pressure lower than atmospheric pressure, for example, in a range of 1 to 1000 Pa. The supply flow rate of O ₂ gas controlled by the mass flow controller 241c is, for example, a flow rate in the range of 1000 to 10,000 sccm (1 to 10 slm). The supply flow rate of the H ₂ gas controlled by the mass flow controller 241d is, for example, a flow rate in the range of 1000 to 10,000 sccm (1 to 10 slm). Note that the time for exposing the O ₂ gas and H ₂ gas to the wafer 200 is, for example, a time within a range of 1 to 120 seconds. The temperature of the heater 207 is set so that the temperature of the wafer 200 becomes a temperature within a range of 350 to 1000 ° C., for example. Note that it was confirmed that the effect of improving the oxidizing power by adding H ₂ gas to the O ₂ gas under a reduced pressure atmosphere can be obtained at a temperature within this range. It has also been confirmed that if the temperature of the wafer 200 is too low, the effect of improving the oxidizing power cannot be obtained. However, in consideration of the throughput, the temperature of the wafer 200 is a temperature at which the effect of improving the oxidizing power is obtained, and is in the same temperature range as when the HCD gas is supplied in Step 1a, that is, in Step 1a and Step 3a. It is preferable to set the temperature of the heater 207 so that the temperature in the processing chamber 201 is maintained in a similar temperature range. In this case, the temperature of the heater 207 is set so that the temperature of the wafer 200 in step 1a and step 3a, that is, the temperature in the processing chamber 201 becomes a constant temperature in the range of 350 to 950 ° C., preferably 700 to 800 ° C. Set. Furthermore, it is more preferable to set the temperature of the heater 207 so that the temperature in the processing chamber 201 is maintained in a similar temperature range from step 1a to step 4a (described later). In this case, the temperature of the heater 207 is set so that the temperature in the processing chamber 201 becomes a constant temperature in the range of 350 to 950 ° C., preferably 700 to 800 ° C. in steps 1a to 4a (described later). Incidentally, in order to obtain the effect of the oxidizing power improvement by H ₂ gas added to the O ₂ gas under a reduced pressure atmosphere, although the temperature in the processing chamber 201 is required to be 350 ° C. or higher, the temperature in the processing chamber 201 Is preferably 400 ° C. or higher, more preferably 450 ° C. or higher. If the temperature in the processing chamber 201 is 400 ° C. or higher, an oxidizing power exceeding the oxidizing power by the O ₃ oxidation treatment performed at a temperature of 400 ° C. or higher can be obtained. For example, an oxidizing power exceeding the oxidizing power by the O ₂ plasma oxidation treatment performed at a temperature of 450 ° C. or higher can be obtained.

By supplying O ₂ gas and H ₂ gas into the processing chamber 201 under the above-mentioned conditions, the O ₂ gas and H ₂ gas are thermally activated by non-plasma and react in a heated reduced pressure atmosphere. , Thereby producing an oxidizing species containing oxygen, such as atomic oxygen (O). Then, an oxidation treatment is performed on the silicon-containing layer formed on the wafer 200 in Step 1a mainly by this oxidizing species. By this oxidation treatment, the silicon-containing layer is changed (modified) into a silicon oxide layer (SiO ₂ layer, hereinafter, also simply referred to as “SiO layer”). According to this oxidation treatment, as described above, the oxidizing power can be greatly improved as compared with the case where O ₂ gas is supplied alone. That is, by adding H ₂ gas to O ₂ gas in a reduced pressure atmosphere, a significant effect of improving the oxidizing power can be obtained compared to the case of supplying O ₂ gas alone.

At this time, at least one or both of O ₂ gas and H ₂ gas can be activated by plasma and flowed. O ₂ gas and / or H ₂ gas that flowed activated with plasma, it is possible to generate a higher oxidation species of energy, by performing the oxidation treatment by the oxidizing species, etc. the device characteristics are improved The effect of can also be considered. For example, when both O ₂ gas and H ₂ gas are activated by plasma, high frequency power is applied between the first rod-shaped electrode 269 and the second rod-shaped electrode 270 from the high-frequency power source 273 via the matching device 272. Thus, the mixed gas of O ₂ gas and H ₂ gas supplied into the buffer chamber 237 is plasma-excited, supplied as active species into the processing chamber 201 from the gas supply hole 248c, and exhausted from the exhaust pipe 231. At this time, the high-frequency power applied between the first rod-shaped electrode 269 and the second rod-shaped electrode 270 from the high-frequency power source 273 is set to be, for example, a power in the range of 50 to 1000 W. Other processing conditions are the same as those described above. In the above temperature range, the O ₂ gas and the H ₂ gas are activated by heat and sufficiently react to generate a sufficient amount of oxidized species. Therefore, sufficient oxidizing power can be obtained even if O ₂ gas and H ₂ gas are thermally activated by non-plasma. Note that when the O ₂ gas and the H ₂ gas are activated and supplied with heat, a soft reaction can be generated, and the above-described oxidation treatment can be performed softly.

As the oxygen-containing gas, that is, the oxidizing gas, ozone (O ₃ ) gas or the like may be used in addition to oxygen (O ₂ ) gas. In addition, when the hydrogen-containing gas addition effect to the nitrogen monoxide (NO) gas and the nitrous oxide (N ₂ O) gas was tried in the above temperature range, the NO gas alone supply and the N ₂ O gas alone supply were performed. It was confirmed that the effect of improving the oxidizing power was not obtained. That is, it is preferable to use a nitrogen-free oxygen-containing gas (a gas that does not contain nitrogen but contains oxygen) as the oxygen-containing gas. As the hydrogen-containing gas, that is, the reducing gas, deuterium (D ₂ ) gas or the like may be used in addition to hydrogen (H ₂ ) gas. Note that when ammonia (NH ₃ ) gas, methane (CH ₄ ) gas, or the like is used, nitrogen (N) impurities or carbon (C) impurities may be mixed into the film. That is, as the hydrogen-containing gas, it is preferable to use a hydrogen-containing gas that does not contain other elements (a gas that does not contain other elements and contains hydrogen or deuterium). That is, as the oxygen-containing gas, at least one gas selected from the group consisting of O ₂ gas and O ₃ gas can be used, and as the hydrogen-containing gas, selected from the group consisting of H ₂ gas and D ₂ gas At least one gas can be used.

[Step 4a]
After changing the silicon-containing layer to the silicon oxide layer, the valve 243c of the third gas supply pipe 232c is closed, and the supply of O ₂ gas is stopped. Further, the valve 243d of the fourth gas supply pipe 232d is closed, and the supply of H ₂ gas is stopped. 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 remaining O ₂ gas and H ₂ gas are removed from the processing chamber 201. At this time, the valves 243e, 243f, 243g, and 243h are opened, and N ₂ gas as an inert gas is supplied into the processing chamber 201. The N ₂ gas acts as a purge gas, thereby further enhancing the effect of removing the O ₂ gas and H ₂ gas remaining in the processing chamber 201 or contributing to the formation of the silicon oxide layer from the processing chamber 201. (Residual gas removal).

The temperature of the heater 207 at this time is set so that the temperature of the wafer 200 is in the range of 350 to 950 ° C., preferably 700 to 800 ° C., as in the case of supplying the O ₂ gas and H ₂ gas. The supply flow rate of N ₂ gas as the purge gas is set to a flow rate in the range of 200 to 1000 sccm (0.2 to 1 slm). As described above, the volume flow rate of the N ₂ gas as the purge gas does not need to be increased as much as the volume flow rate of the N ₂ gas as the deposition / adsorption inhibition gas, and a sufficient purge effect can be obtained with a smaller flow rate. As the purge gas, a rare gas such as Ar, He, Ne, or Xe may be used in addition to the N ₂ gas.

  The above-described steps 1a to 4a are set as one cycle, and the silicon oxide film having a predetermined thickness can be formed on the wafer 200 by performing this cycle at least once, preferably a plurality of times. The silicon oxide film serves as a base film for a silicon nitride film formed in a process described later.

  If the thickness of the silicon oxide film formed as the base film is less than 2 nm, etch pits may be generated on the surface of the wafer 200 due to thermal etching. If the silicon oxide film formed as the base film is too thick, the effective dielectric constant of the insulating film formed by laminating the silicon oxide film and the silicon nitride film is lowered, and the silicon nitride film is used as the insulating film. The advantage of using it may be impaired. Therefore, the thickness of the silicon oxide film formed as the base film is preferably 2 nm or more and 4 nm or less, and more preferably 2 nm.

(Silicon nitride film formation process)
Subsequently, the following steps 1b to 4b are set as one cycle, and this cycle is performed a predetermined number of times to form a silicon nitride film having a predetermined thickness on the silicon oxide film as the base film.

[Step 1b]
HCD gas and N ₂ gas are supplied and exhausted into the heated processing chamber 201 in a decompressed state by the same procedure as in step 1a of the silicon oxide film forming process (HCD gas + N ₂ gas supply).

At this time, the APC valve 244 is appropriately adjusted to maintain the pressure in the processing chamber 201 at a pressure lower than atmospheric pressure, for example, in a range of 10 to 1000 Pa. The supply flow rate of the HCD gas controlled by the mass flow controller 241a is, for example, a flow rate in the range of 20 to 1000 sccm (0.02 to 1 slm). The supply flow rate of N ₂ gas as the deposition / adsorption inhibition gas controlled by the mass flow controller 241e is larger than the supply flow rate of the HCD gas, for example, a flow rate in the range of 1000 to 20000 sccm (1 to 20 slm). The time for exposing the HCD gas to the wafer 200 is, for example, a time within a range of 1 to 120 seconds. The temperature of the heater 207 is set so that the CVD reaction occurs in the processing chamber 201 in the above-described pressure zone. That is, the temperature of the heater 207 is set so that the temperature of the wafer 200 is, for example, 350 to 950 ° C., preferably 700 to 950 ° C., more preferably 750 to 950 ° C., and still more preferably 800 to 950 ° C. To do. Note that when the temperature of the wafer 200 is less than 350 ° C., the HCD is difficult to be decomposed and adsorbed on the wafer 200. When the temperature of the wafer 200 exceeds 950 ° C., the CVD reaction becomes too strong, the action of the deposition / adsorption inhibition gas does not work sufficiently, and it becomes difficult to improve the deterioration of the film thickness uniformity. On the other hand, when the temperature of the wafer 200 is lower than 700 ° C., the film thickness uniformity is relatively good, and the film thickness uniformity is significantly deteriorated in a high temperature region of 700 ° C. or higher. Especially effective. Further, when the temperature of the wafer 200 is less than 800 ° C., particularly less than 750 ° C., the hydrogen taken into the film is likely to remain, and a low-density film having many hydrogen adsorption sites (many defects) is formed. The From the above, the temperature of the wafer 200 is 350 to 950 ° C., preferably 700 to 950 ° C., more preferably 750 to 950 ° C., and still more preferably 800 to 950 ° C. If the temperature of the wafer 200 is set to 750 to 950 ° C., more preferably 800 to 950 ° C., the action of the deposition / adsorption inhibition gas can be sufficiently generated, and further, hydrogen taken into the film remains. This makes it possible to form a high-density film that is difficult (desorbed easily) and has few hydrogen adsorption sites (small defects). That is, in this temperature range, it is possible to form a film with extremely low hydrogen concentration in the film and extremely good film thickness uniformity.

  By supplying the HCD gas into the processing chamber 201 under the above-described conditions, that is, conditions under which a CVD reaction occurs, silicon as a silicon-containing layer of less than one atomic layer to several atomic layers is formed on the silicon oxide film (underlying film). A layer (Si layer) is formed. The silicon-containing layer may be an HCD gas adsorption layer. Here, the silicon layer is a generic name including a continuous layer made of silicon, a discontinuous layer, and a silicon thin film formed by overlapping these layers. A continuous layer made of silicon may be referred to as a silicon thin film. The HCD gas adsorption layer includes a discontinuous chemical adsorption layer as well as a continuous chemical adsorption layer of gas molecules of the HCD gas. In addition, the layer less than 1 atomic layer means the atomic layer formed discontinuously. Under the condition that the HCD gas self-decomposes, silicon is deposited on the silicon oxide film to form a silicon layer. Under the condition that the HCD gas does not self-decompose, the HCD gas adsorbed layer is formed by adsorbing the HCD gas on the silicon oxide film. When the thickness of the silicon-containing layer formed on the silicon oxide film exceeds several atomic layers, the nitriding action in step 3b described later does not reach the entire silicon-containing layer. The minimum value of the silicon-containing layer that can be formed on the silicon oxide film is less than one atomic layer. Therefore, the thickness of the silicon-containing layer is preferably set to be less than one atomic layer to several atomic layers. Note that it is preferable to form a silicon layer on the silicon oxide film because the deposition rate can be increased, rather than forming an HCD gas adsorption layer on the silicon oxide film.

At this time, as described above, the N ₂ gas as the deposition / adsorption inhibition gas is supplied toward the wafer 200 at a large flow rate together with the HCD gas from the same nozzle as the first nozzle 233a that supplies the HCD gas. The flow rate of the HCD gas, particularly the flow rate of the HCD gas flowing in a direction parallel to the surface of the wafer 200 (crossing the surface of the wafer 200) is increased. That is, the HCD gas is strongly blown in the direction parallel to the surface of the wafer 200. As a result, the silicon deposition efficiency or the HCD gas adsorption efficiency on the silicon oxide film can be lowered, and the silicon-containing layer can be formed on the silicon oxide film while suppressing the deposition or adsorption. By the action of the deposition / adsorption inhibition gas, the deposition or adsorption center of the silicon-containing layer can be moved from the edge side of the wafer 200 to the center as shown in FIG. And the thinnest part can be reduced. For example, even in a region where the adsorption reaction breaks down in a high temperature region of 700 ° C. or higher, that is, in a region where deposition or adsorption of the silicon-containing layer is excessive, the silicon-containing layer can be uniformly formed. It becomes possible to form.

FIG. 10A is a diagram schematically showing the state of silicon deposition or HCD gas adsorption when the flow rate of the HCD gas flowing parallel to the surface of the wafer 200 is small. FIG. 10B is a diagram schematically showing the state of silicon deposition or HCD gas adsorption when the flow rate of the HCD gas flowing in the direction parallel to the surface of the wafer 200 is large. In FIG. 10, for convenience, a silicon oxide film as a base film is not shown. The white arrows in FIG. 10 indicate the flow directions of the HCD gas and the N ₂ gas, and white circles (◯) on the wafer 200 indicate Si atoms deposited on the wafer 200 (on the silicon oxide film) or Wafer 20
HCD gas molecules adsorbed on 0 (on the silicon oxide film) are shown. In FIG. 10, only the left half of the wafer 200 is shown for convenience.

  As shown in FIG. 10, by increasing the flow rate of the HCD gas flowing in the direction parallel to the surface of the wafer 200, the thickness of the silicon-containing layer is reduced as a whole, and the deposition or adsorption center of the silicon-containing layer is set at the wafer 200. It is possible to move from the edge side to the center. Further, the difference between the thickest portion and the thinnest portion of the silicon-containing layer can be reduced, and the silicon-containing layer can be formed uniformly over the surface of the wafer 200.

Note that the supply flow rate of the N ₂ gas as the deposition / adsorption inhibition gas is preferably set to a flow rate in the range of 1 to 20 slm as described above, and is preferably larger than the supply flow rate of the HCD gas. In this way, the supply flow rate of N ₂ gas is set, and the volume flow rate of N ₂ gas is set to be larger than the volume flow rate of HCD gas. Make it faster than flowing the gas alone. That is, the HCD gas is blown stronger in the direction parallel to the surface of the wafer 200 than when the HCD gas is supplied alone. The supply flow rate of N ₂ gas as the deposition / adsorption inhibition gas is preferably larger than the supply flow rate of NH ₃ gas supplied into the processing chamber 201 in step 3b described later. Thus setting the supply flow rate of N ₂ gas, the volumetric flow rate of N ₂ gas, by a high flow rate than the volume flow of the NH ₃ gas, the flow rate of the HCD gas flowing in the direction parallel to the wafer 200 surface, The flow rate of the NH ₃ gas flowing in the direction parallel to the surface of the wafer 200 is set to be faster. That is, the HCD gas is blown in a direction parallel to the surface of the wafer 200 stronger than the NH ₃ gas is blown in a direction parallel to the surface of the wafer 200. Furthermore, the supply flow rate of N ₂ gas as the deposition / adsorption inhibition gas is preferably larger than the supply flow rate of N ₂ gas as the purge gas supplied into the processing chamber 201 in steps 2b and 4b described later. . In this way, the supply flow rate of N ₂ gas as the deposition / adsorption inhibition gas is set, and the volume flow rate of N ₂ gas as the deposition / adsorption inhibition gas is set larger than the volume flow rate of N ₂ gas as the purge gas. Thus, the flow rate of the HCD gas flowing in the direction parallel to the surface of the wafer 200 is made faster than the flow rate of the N ₂ gas as the purge gas flowing in the direction parallel to the surface of the wafer 200. That is, it is stronger than spraying N ₂ gas as a purge gas in the direction parallel to the surface of the wafer 200, and HCD gas is sprayed in the direction parallel to the surface of the wafer 200.

Specifically, the volume flow rate of the N ₂ gas as the deposition / adsorption inhibition gas is about 10 to 30 times the volume flow rate of the HCD gas and about 5 to 30 times the volume flow rate of the N ₂ gas as the purge gas. Is preferable. By setting the volume flow rate of N ₂ gas as the deposition / adsorption inhibition gas to about 10 to 30 times the volume flow rate of HCD gas, the flow rate of HCD gas flowing in the direction parallel to the surface of the wafer 200 can be increased sufficiently. Thus, deposition or adsorption of the silicon-containing layer can be more sufficiently suppressed, and the deposition or adsorption center can be easily set from the edge side of the wafer 200 to the center. It is also easy to reduce the difference between the thickest part and the thinnest part of the silicon-containing layer. As a result, the film thickness uniformity can be more sufficiently improved. Further, it is possible to prevent the practical flow rate from being obtained because the flow rate of the HCD gas becomes too high and the deposition or adsorption of the silicon-containing layer is suppressed too much.

As raw materials containing Si, not only inorganic raw materials such as TCS (tetrachlorosilane, SiCl ₄ ), DCS (dichlorosilane, SiH ₂ Cl ₂ ), SiH ₄ (monosilane), but also aminosilane-based 4DMAS (tetrakis) are included. Dimethylaminosilane, Si [N (CH ₃ ) ₂ ] ₄ ), 3DMAS (trisdimethylaminosilane, Si [N (CH ₃ ) ₂ ] ₃ H), 2DEAS (bisdiethylaminosilane, Si [N (C ₂ H ₅ ) ₂ ] ₂ H ₂ ), BTBAS (Bisturary butylaminosilane, SiH ₂ [NH (C ₄ H ₉ )] ₂ ) or the like may be used.

As the inert gas as the deposition / adsorption inhibition gas, a rare gas such as Ar, He, Ne, or Xe may be used in addition to the N ₂ gas. Further, a hydrogen-containing gas may be used as the deposition / adsorption inhibition gas. As the hydrogen-containing gas, for example, hydrogen (H ₂ ) gas, deuterium (D ₂ ) gas, or the like can be used. FIG. 7 shows an example of a film forming sequence using H ₂ gas, which is a hydrogen-containing gas, as the deposition / adsorption inhibition gas. The supply flow rate of H ₂ gas as the deposition / adsorption inhibition gas is set to a flow rate in the range of 1000 to 20000 sccm (1 to 20 slm), similarly to the supply flow rate of N ₂ gas as the deposition / adsorption inhibition gas. Note that, for example, at a high temperature of 750 ° C. or higher, preferably 800 ° C. or higher, the hydrogen taken into the film hardly remains (is easily desorbed). There is no effect on the hydrogen concentration reduction effect. Even in this case, a high-density film with few hydrogen adsorption sites (small defects) is formed. Note that it is conceivable to extract Cl from the HCD gas by supplying H ₂ gas when the HCD gas is supplied, thereby improving the film formation rate and reducing Cl impurities in the film.

[Step 2b]
After the silicon-containing layer is formed on the silicon oxide film, the HCD gas is removed from the processing chamber 201 and the processing chamber 201 is purged with N ₂ gas by the same procedure as in step 2a of the silicon oxide film forming step. (Residual gas removal).

The temperature of the heater 207 at this time is in the range of 350 to 950 ° C., preferably 700 to 950 ° C., more preferably 750 to 950 ° C., more preferably 800 to 950 ° C. Set the temperature to be within the range. The supply flow rate of N ₂ gas as the purge gas is set to a flow rate in the range of 200 to 1000 sccm (0.2 to 1 slm). Note that the volume flow rate of the N ₂ gas as the purge gas does not need to be as large as the volume flow rate of the N ₂ gas as the deposition / adsorption inhibition gas, and a sufficient purge effect can be obtained with a smaller flow rate. In other words, the volume flow rate of N ₂ gas as the deposition / adsorption inhibition gas needs to be larger than the volume flow rate of N ₂ gas as the purge gas. That is, in order to obtain the deposition / adsorption suppression effect of the silicon-containing layer, the volume flow rate of the N ₂ gas as the deposition / adsorption inhibition gas is set to be larger than the volume flow rate of the N ₂ gas sufficient to obtain the purge effect. There is a need to. Therefore, when removing the residual gas in the processing chamber 201 by purging, the mass flow controller 241e is controlled, and the supply flow rate of N ₂ gas supplied from the first inert gas supply pipe 232e is changed from 1 to 20 slm to 0.2. It will be changed to ˜1 slm and the volume flow rate of N ₂ gas will be reduced. In addition to the N ₂ gas, a rare gas such as Ar, He, Ne, or Xe may be used as the purge gas.

[Step 3b]
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 through the second gas supply pipe 232b. The NH ₃ gas flows from the second gas supply pipe 232b and the flow rate is adjusted by the mass flow controller 241b. The NH ₃ gas whose flow rate has been adjusted is supplied from the gas supply hole 248b of the second nozzle 233b into the buffer chamber 237 in a depressurized state. At this time, high frequency power is not applied between the first rod-shaped electrode 269 and the second rod-shaped electrode 270. As a result, the NH ₃ gas supplied into the buffer chamber 237 is activated by heat and supplied from the gas supply hole 248 c of the buffer chamber 237 into the heated processing chamber 201 in a decompressed state, and is supplied from the exhaust pipe 231. It is exhausted (NH ₃ gas supply).

At this time, the valve 243f of the second inert gas supply pipe 232f may be opened to supply N ₂ gas as an inert gas from the second inert gas supply pipe 232f. The flow rate of the N ₂ gas is adjusted by the mass flow controller 241f, and the N ₂ gas is supplied into the second gas supply pipe 232b. In this case, a mixed gas of NH ₃ gas and N ₂ gas is supplied from the second nozzle 233b. In addition, as the inert gas, in addition to N ₂ gas, Ar, He, Ne, Xe
A noble gas such as may be used.

At this time, the APC valve 244 is appropriately adjusted to maintain the pressure in the processing chamber 201 at a pressure lower than atmospheric pressure, for example, within a range of 1 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 10000 sccm (0.1 to 10 slm). The time for exposing the NH ₃ gas to the wafer 200 is, for example, a time within a range of 1 to 120 seconds. The temperature of the heater 207 is set so that the temperature of the wafer 200 is in a range of 350 to 1200 ° C., for example. Note that it was confirmed that if the temperature was within this range, the effect of nitriding with NH ₃ gas under a reduced pressure atmosphere, that is, the nitriding reaction of the silicon-containing layer was obtained. It was also confirmed that the nitriding effect could not be obtained if the temperature of the wafer 200 was too low. However, considering the throughput, the temperature of the wafer 200 is such that the nitridation reaction of the silicon-containing layer occurs, and is in the same temperature range as when the HCD gas is supplied in Step 1b, that is, Step 1b and Step 3b. Therefore, it is preferable to set the temperature of the heater 207 so that the temperature in the processing chamber 201 is maintained in a similar temperature range. In this case, the temperature of the wafer 200 in step 1b and step 3b, that is, the temperature in the processing chamber 201 is 350 to 950 ° C., preferably 700 to 950 ° C., more preferably 750 to 950 ° C., and still more preferably 800 to 950 ° C. The temperature of the heater 207 is set so as to be a constant temperature within the range. Furthermore, it is more preferable to set the temperature of the heater 207 so that the temperature in the processing chamber 201 is maintained in a similar temperature range from step 1b to step 4b (described later). In this case, the temperature in the processing chamber 201 is 350 to 950 ° C., preferably 700 to 950 ° C., more preferably 750 to 950 ° C., and still more preferably 800 to 950 ° C. from Step 1b to Step 4b (described later). The temperature of the heater 207 is set so as to be a constant temperature. Note that when the temperature in the processing chamber 201 is set to 550 ° C. or higher, the effect of improving the nitriding power by the NH ₃ gas in a reduced pressure atmosphere can be obtained. In order to further enhance the effect of improving the nitriding power, the temperature in the processing chamber 201 is preferably 600 ° C. or higher, and more preferably 700 ° C. or higher. Note that the NH ₃ gas can cause a soft reaction when supplied by being activated by heat rather than being activated by plasma, and can perform nitriding described later softly.

By supplying the NH ₃ gas into the processing chamber 201 under the above-described conditions, the NH ₃ gas is thermally activated by non-plasma in a heated reduced-pressure atmosphere or pyrolyzed and contains nitrogen. Nitriding species are generated. At this time, since the HCD gas does not flow in the processing chamber 201, the NH ₃ gas does not cause a gas phase reaction, and the NH ₃ gas is obtained by being thermally activated or thermally decomposed. The nitrided species reacted with at least a portion of the silicon-containing layer formed on the silicon oxide film in step 1b. As a result, a nitriding process is performed on the silicon-containing layer, and the silicon-containing layer is changed into a silicon nitride layer (Si ₃ N ₄ layer, hereinafter, also simply referred to as a SiN layer) by the nitriding process (modified). Quality).

At this time, NH ₃ gas may be activated by plasma and flowed. By activating and flowing NH ₃ gas with plasma, a higher-energy nitriding species can be generated. By performing nitriding with this nitriding species, effects such as improved device characteristics can be considered. When NH ₃ gas is activated by plasma, high frequency power is applied between the first rod-shaped electrode 269 and the second rod-shaped electrode 270 from the high-frequency power source 273 via the matching device 272 to be supplied into the buffer chamber 237. The NH ₃ gas thus excited is plasma-excited, supplied as an active species into the processing chamber 201 from the gas supply hole 248c, and exhausted from the exhaust pipe 231. At this time, the high-frequency power applied between the first rod-shaped electrode 269 and the second rod-shaped electrode 270 from the high-frequency power source 273 is set to be, for example, a power in the range of 50 to 1000 W. Other processing conditions are the same as those described above. In the above temperature range, the NH ₃ gas is sufficiently activated by heat, and a sufficient amount of nitriding species is generated. Therefore, sufficient nitriding power can be obtained even when NH ₃ gas is thermally activated by non-plasma. Note that the NH ₃ gas activated by heat can be supplied to cause a soft reaction, and the above-described nitriding treatment can be performed softly.

As the nitrogen-containing gas, other than NH ₃ gas, diazine (N ₂ H ₂ ) gas, hydrazine (N ₂ H ₄ ) gas, N ₃ H ₈ gas, amine-based gas, or the like may be used.

[Step 4b]
After changing the silicon-containing layer to the silicon nitride layer, the valve 243b of the second gas supply pipe 232b is closed, and the supply of NH ₃ gas is stopped. 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 remaining NH ₃ gas is removed from the processing chamber 201. At this time, the valves 243e, 243f, 243g, and 243h are opened, and N ₂ gas as an inert gas is supplied into the processing chamber 201. The N ₂ gas acts as a purge gas, which can further enhance the effect of removing the NH ₃ gas remaining in the processing chamber 201 or contributing to the formation of the silicon nitride layer from the processing chamber 201 ( Residual gas removal).

The temperature of the heater 207 at this time is 350 to 950 ° C., preferably 700 to 950 ° C., more preferably 750 to 950 ° C., and still more preferably 800 to 950 ° C., as in the case of supplying the NH ₃ gas. Set the temperature within the range. The supply flow rate of N ₂ gas as the purge gas is set to a flow rate in the range of 200 to 1000 sccm (0.2 to 1 slm). As described above, the volume flow rate of the N ₂ gas as the purge gas does not need to be increased as much as the volume flow rate of the N ₂ gas as the deposition / adsorption inhibition gas, and a sufficient purge effect can be obtained with a smaller flow rate. As the purge gas, a rare gas such as Ar, He, Ne, or Xe may be used in addition to the N ₂ gas.

  By performing the above-described steps 1b to 4b as one cycle and performing this cycle at least once, preferably a plurality of times, a silicon nitride film having a predetermined thickness can be formed on the silicon oxide film as the base film. . FIG. 11 is a cross-sectional view showing a state in which a silicon oxide film and a silicon nitride film are sequentially stacked on the wafer 200 by the above-described film forming sequence. The silicon oxide film forming step and the silicon nitride film forming step are preferably performed in a state where the temperature of the wafer 200 is maintained in a similar temperature range.

(Purge and return to atmospheric pressure)
When the silicon nitride film having a predetermined thickness is formed, the valves 243e, 243f, 243g, and 243h are opened, and the first inert gas supply pipe 232e, the second inert gas supply pipe 232f, and the third inert gas supply pipe. N ₂ gas as an inert gas is supplied into the processing chamber 201 from each of 232 g and the fourth inert gas supply pipe 232 h and exhausted from the exhaust pipe 231. The N ₂ gas acts as a purge gas, whereby the inside of the processing chamber 201 is purged with an inert gas, and the gas remaining in the processing chamber 201 is removed from the inside of the processing chamber 201 (purge). Thereafter, the atmosphere in the processing chamber 201 is replaced with an inert gas, and the pressure in the processing chamber 201 is returned to normal pressure (return to atmospheric pressure).

(Boat unload and wafer discharge)
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 held 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).

(3) Effects according to the present embodiment According to the present embodiment, the following one or more effects are achieved.

  According to the present embodiment, the silicon nitride film is not directly formed on the wafer 200, but is formed through the silicon oxide film as the base film. By doing so, even if the film formation temperature of the silicon nitride film is increased, the influence of adsorbed oxygen, entrained oxygen, etc. on the wafer 200 surface on the interface between the wafer 200 surface and the silicon nitride film is reduced. Can do. Further, since the surface of the wafer 200 is covered with the silicon oxide film, even if the film formation temperature of the silicon nitride film is increased, generation of etch pits or the like on the surface of the wafer 200 due to thermal etching can be suppressed, and the surface of the wafer 200 can be suppressed. An increase in effective surface area can be prevented. As a result, the influence on the electrical characteristics of the silicon nitride film can be reduced, the leakage current of the silicon nitride film can be reduced, and the EOT can be reduced.

  According to the present embodiment, the thickness of the silicon oxide film as the base film is 2 nm or more. Thereby, it is possible to more reliably avoid the occurrence of etch pits on the surface of the wafer 200 due to thermal etching. The film thickness of the silicon oxide film as the base film is 4 nm or less. Thereby, it is possible to prevent a decrease in effective dielectric constant of the insulating film formed by laminating the silicon oxide film and the silicon nitride film.

In step 1a of the present embodiment, than to the N ₂ gas _is supplied as a deposition-adsorption inhibiting gas from the first nozzle 233a with HCD gas into the processing chamber 201 at a large flow rate as described above, HCD gas In particular, the flow rate of the HCD gas ejected from the gas supply hole 248a of the first nozzle 233a toward the wafer 200 and flowing parallel to the surface of the wafer 200 (crossing the surface of the wafer 200) is increased. Thereby, the deposition efficiency of silicon on the wafer 200 or the adsorption efficiency of the HCD gas can be lowered, and the silicon-containing layer can be formed on the wafer 200 while suppressing the deposition of silicon or the adsorption of the HCD gas. become. By the action of the deposition / adsorption inhibition gas, the deposition or adsorption center of the silicon-containing layer can be moved from the edge side of the wafer 200 to the center, and the thickest portion and the thinnest portion of the silicon-containing layer can be moved. The difference can be reduced, and for example, even in a region where the adsorption reaction collapses in a high temperature region of 700 ° C. or higher, that is, in a region where the deposition or adsorption of the silicon-containing layer is excessive, a silicon-containing layer can be formed uniformly. Become.

In Step 3a of the present embodiment, O ₂ gas and H ₂ gas are reacted in a heated reduced pressure atmosphere to generate an oxidizing species containing oxygen such as atomic oxygen (O). By using the step of changing the silicon-containing layer into the silicon oxide layer, the Si—N, Si—Cl, Si—H, and Si—C bonds in which the energy of the oxidized species is contained in the silicon-containing layer are obtained. Separate. Since the energy for forming the Si—O bond is higher than the bond energy of Si—N, Si—Cl, Si—H, and Si—C, the energy required for forming the Si—O bond is converted to silicon to be oxidized. By giving to the containing layer, Si—N, Si—Cl, Si—H, and Si—C bonds in the silicon containing layer are cut off. N, H, Cl, and C from which the bond with Si has been removed are removed from the film and discharged as N ₂ , H ₂ , Cl ₂ , HCl, CO _{2, and the} like. Further, the remaining Si bonds due to the disconnection of N, H, Cl, and C are combined with O contained in the oxidized species. In this way, the silicon-containing layer is changed into a SiO ₂ layer. The SiO ₂ film formed by the film forming sequence of this embodiment has a very low concentration of nitrogen, hydrogen, chlorine, and carbon, and a Si / O ratio that is very close to the stoichiometric composition of 0.5. It was confirmed that

In Step 3a of the present embodiment, O ₂ gas and H ₂ gas are supplied from the same second nozzle 233b into the processing chamber 201 through the buffer chamber 237, and the second nozzle 233b and the buffer chamber 237 are supplied. The inside is heated to the same temperature as in the processing chamber 201. Therefore, the O ₂ gas and the H ₂ gas are the second nozzle 233 that is in a heated pressure atmosphere less than atmospheric pressure.
The reaction occurs in b and in the buffer chamber 237, and oxidizing species including oxygen such as atomic oxygen (O) is generated in the second nozzle 233b and the buffer chamber 237. Further, the pressure in the second nozzle 233 b and the buffer chamber 237 is higher than that in the processing chamber 201. Therefore, the reaction between the O ₂ gas and the H ₂ gas in the second nozzle 233b and the buffer chamber 237 is promoted, and more oxidizing species generated by the reaction between the O ₂ gas and the H ₂ gas can be generated. Thus, the oxidizing power can be further improved. Further, since the O ₂ gas and the H ₂ gas can be evenly mixed in the second nozzle 233b and the buffer chamber 237 before being supplied into the processing chamber 201, the O ₂ gas and the H ₂ gas can be mixed. The reaction can be performed uniformly in the two nozzles 233b, the concentration of oxidizing species can be made uniform, and the oxidizing power between the wafers 200 can be made uniform. In this way, by supplying O ₂ gas and H ₂ gas from the same second nozzle 233b into the processing chamber 201, higher oxidizing power improvement effect and oxidizing power equalizing effect can be obtained. Note that when the plasma is not used, the buffer chamber 237 can be omitted, but in this case, the same effect as described above can be obtained.

However, when O ₂ gas and H ₂ gas are supplied from the same second nozzle 233 b into the processing chamber 201 via the buffer chamber 237, more oxidizing species are generated in the second nozzle 233 b and the buffer chamber 237. Although it is possible, the generated oxidized species may be deactivated when passing through the second nozzle 233b or the buffer chamber 237, and the amount reaching the wafer 200 may be reduced. . On the other hand, if O ₂ gas and H ₂ gas are supplied into the processing chamber 201 from different nozzles, the O ₂ gas and H ₂ gas are mixed in the processing chamber 201 for the first time. Oxidized species are generated in the processing chamber 201, and it is possible to prevent deactivation of the oxidized species in the second nozzle 233b and the buffer chamber 237.

Further, if the silicon oxide film is formed by the film forming sequence of the present embodiment, the film thickness uniformity in the wafer 200 plane is better than that in the case of forming the silicon oxide film by a general CVD method. It was confirmed. Note that the general CVD method refers to a method of simultaneously forming DCS and N ₂ O, which are inorganic materials, and forming a silicon oxide film (HTO (High Temperature Oxide) film) by the CVD method. . Further, it was confirmed that the concentration of impurities such as nitrogen and chlorine in the silicon oxide film formed by the film forming sequence of the present embodiment is extremely lower than that of a silicon oxide film formed by a general CVD method. Further, it was confirmed that the impurity concentration in the silicon oxide film formed by the film forming sequence of this embodiment is extremely lower than that of the silicon oxide film formed by the CVD method using an organic silicon raw material. Further, according to the film forming sequence of the present embodiment, it was confirmed that even when an organic silicon raw material was used, the film thickness uniformity in the wafer surface and the impurity concentration in the film were good. .

In step 1b of the present embodiment, than to the N ₂ gas _is supplied as a deposition-adsorption inhibiting gas from the first nozzle 233a with HCD gas into the processing chamber 201 at a large flow rate as described above, HCD gas In particular, the flow rate of the HCD gas ejected from the gas supply hole 248a of the first nozzle 233a toward the wafer 200 and flowing parallel to the surface of the wafer 200 (crossing the surface of the wafer 200) is increased. Thereby, the deposition efficiency of silicon on the wafer 200 or the adsorption efficiency of the HCD gas can be lowered, and the silicon-containing layer can be formed on the wafer 200 while suppressing the deposition of silicon or the adsorption of the HCD gas. become. By the action of the deposition / adsorption inhibition gas, it becomes possible to move the deposition or adsorption center of the silicon-containing layer from the edge side of the wafer 200 to the center. Even in a region where the deposition or adsorption of the silicon-containing layer is excessive, the silicon-containing layer can be formed uniformly.

In step 3b of the present embodiment, the silicon-containing layer is changed into a silicon nitride layer by using a nitriding species obtained by activating or thermally decomposing NH ₃ gas in a heated reduced pressure atmosphere. The energy of the nitriding species is not only Si—H bond but also N—H bond having higher bond energy than Si—H bond, so that H (hydrogen) is removed and discharged as H ₂ etc. The Si and N from which the bond with hydrogen is cut off are combined with N and Si, respectively, to form a new Si—N bond. The silicon nitride film formed by the film forming sequence of the present embodiment has a hydrogen concentration in the film that is one order of magnitude lower than that of a silicon nitride film (CVD-SiN film) formed by a general CVD method, and becomes a very high quality film. It was confirmed. Note that the general CVD method refers to a method in which DCS and NH ₃ which are inorganic materials are simultaneously supplied to form a silicon nitride film by the CVD method.

  Further, if the silicon nitride film is formed by the film forming sequence of the present embodiment, the film thickness uniformity in the wafer 200 plane is better than that in the case of forming the silicon nitride film by a general CVD method. It was confirmed. Further, it was confirmed that the concentration of impurities such as hydrogen in the silicon nitride film formed by the film forming sequence of the present embodiment is extremely lower than that of a silicon nitride film formed by a general CVD method. Further, it was confirmed that the hydrogen concentration in the silicon nitride film formed by the film forming sequence of this embodiment is extremely lower than that of the silicon nitride film formed by the CVD method using an organic silicon raw material. Further, according to the film forming sequence of the present embodiment, it is confirmed that the film thickness uniformity in the wafer 200 surface and the hydrogen concentration in the film are good even when the organic silicon raw material is used. did.

  Further, as described above, according to the film forming sequence of this embodiment, a silicon nitride film (hereinafter also referred to as a hydrogen-free SiN film) having a very low hydrogen concentration can be formed on the silicon oxide film. If an insulating film formed by laminating a film and this hydrogen-free SiN film is used as a SAC (Self Align Contact), NBTI (Negative Bias Temperature Instability) characteristics can be improved.

  Moreover, if an insulating film formed by laminating a silicon oxide film and this hydrogen-free SiN film is used as a gate insulating film, it is possible to increase the dielectric breakdown resistance. The Si—H bond is a bond having a weaker binding force than the Si—N bond, and has a high probability of desorption due to hole-electron recombination. The Si-unbonded hand (dangling bond) from which hydrogen is removed becomes a charge trap, contributes to current conduction, and weakens the dielectric breakdown resistance. For this reason, high dielectric breakdown resistance can be obtained by using an insulating film including a hydrogen-free SiN film having no hydrogen (particularly, Si—H bonds) in the film (very small) as a gate insulating film.

  In addition, according to the film forming sequence of the present embodiment, a silicon nitride film (hereinafter also referred to as a stress-free SiN film) having a very low stress can be formed on the silicon oxide film as a base film of 2 to 4 nm. If an insulating film formed by laminating a silicon oxide film and this stress-free SiN film is used in an STI (Shallow Trench Isolation) process, the following merits are obtained. In other words, the Si etching is performed using the SiN film as a mask for forming the STI. However, since the stress of the SiN film is high and the film is formed directly on the wafer, the wafer (channel portion) is damaged and damage is usually caused. A SiN film is formed on a sacrificial oxide film of about 10 nm formed on the wafer. On the other hand, if a laminated film of a silicon oxide film and a stress-free SiN film is used in the STI process, damage to the wafer (channel portion) is caused even if a laminated film including the stress-free SiN film is directly formed on the wafer. Therefore, there is no need to separately form a sacrificial oxide film, and the two steps of forming the sacrificial oxide film and removing the sacrificial oxide film can be reduced. In addition, normally, the SiN film after mask processing is in a state where a large stress is applied only to the back surface of the wafer, and the entire wafer is distorted. However, if an insulating film including a stress-free SiN film is used as a mask, Distortion is eliminated, the area around the polishing becomes uniform, and polishing can be performed more efficiently.

<Other Embodiments of the Present Invention>
In the above-described embodiment, by alternately repeating the step of forming a silicon-containing layer on the wafer 200 and the step of changing the silicon-containing layer into a silicon oxide layer, a silicon oxide film is formed on the wafer 200 as a base film. Although an example of forming by deposition has been described, the present invention is not limited to such a form.

For example, the silicon oxide film as the base film may be formed by thermally oxidizing the surface of the wafer 200 by a technique such as wet oxidation. Further, for example, using an oxidizing species containing oxygen such as atomic oxygen (O) generated by reacting an oxygen-containing gas such as O ₂ gas and a hydrogen-containing gas such as H ₂ gas in a heated reduced-pressure atmosphere. You may form by the reduced pressure oxidation which oxidizes the wafer 200 surface. Further, for example, the wafer 200 may be formed by a CVD method in which a source gas such as HCD gas and an oxygen-containing gas such as O ₂ gas are simultaneously supplied to deposit a silicon oxide film on the wafer 200. Further, for example, it may be formed by an ALD method in which a source gas such as HCD gas and an oxygen-containing gas such as O ₂ gas are alternately supplied to the wafer 200 to deposit a silicon oxide film on the wafer 200. In any case, the silicon oxide film and the silicon nitride film may be continuously formed in the same processing container (in-situ) as in the above-described embodiment, or separately in different processing containers. You may form in.

  The silicon oxide film as the base film is preferably dense. The density of the silicon oxide film includes a silicon oxide film (ALD-SiO film) by a general ALD method, a silicon oxide film (CVD-SiO film) by a general CVD method, and a silicon oxide film by the method of the above-described embodiment. The order of the thermal oxide film increases. That is, among these silicon oxide films, the thermal oxide film has the highest density. Therefore, from that viewpoint, it is most preferable to use a thermal oxide film as the base film. An embodiment using a thermal oxide film as a base film will be described later.

  In the above-described embodiment, the deposition / adsorption inhibition gas increases the flow rate of the HCD gas flowing in the direction parallel to the surface of the wafer 200 to increase the deposition of silicon on the wafer 200 or the silicon oxide film as the base film. The example of suppressing the adsorption of the HCD gas and improving the film thickness uniformity has been described, but the method of increasing the flow rate of the HCD gas is not limited to this.

  For example, by setting the flow resistance inside the reaction tube 203 to the same level as the flow resistance between the wafers 200, the flow rate of the HCD gas flowing in the direction parallel to the wafer 200 surface can be increased. For example, by filling the space above and below the reaction tube 203 with a dummy wafer, a heat insulating plate, etc., the flow rate of the HCD gas flowing in the direction parallel to the surface of the wafer 200 is increased, and the wafer 200 and the silicon oxide film as the underlayer are formed. Silicon deposition or HCD gas adsorption on the substrate can be suppressed, and film thickness uniformity can be improved.

  Further, for example, by setting the conductance between the nozzle 233a for supplying the HCD gas and the wafer 200 to be approximately the same as the conductance between the wafers 200, the flow rate of the HCD gas flowing in the direction parallel to the surface of the wafer 200 can be increased. . For example, by increasing the diameter of the first nozzle 233a or reducing the diameter of the reaction tube 203, the flow rate of the HCD gas flowing in the direction parallel to the surface of the wafer 200 is increased, and the wafer 200 is used as a base film. The deposition of silicon on the silicon oxide film or the adsorption of HCD gas can be suppressed, and the film thickness uniformity can be improved.

Further, for example, by repeating the supply and exhaust of the HCD gas, the flow rate of the HCD gas flowing in the direction parallel to the surface of the wafer 200 can be increased. For example, by increasing the pressure difference between the wafer arrangement region in the reaction tube 203 and the nozzle 233a (in the buffer chamber 237), the flow rate of the HCD gas flowing in the direction parallel to the surface of the wafer 200 is increased. Silicon deposition or HCD gas adsorption on the silicon oxide film as the base film can be suppressed, and the film thickness uniformity can be improved.

  Further, in the above-described embodiment, steps 1a to 4a are performed in this order, and this is defined as one cycle, and this cycle is performed at least once, preferably a plurality of times, so that a silicon oxide film having a predetermined thickness is formed on the wafer 200. Although an example of forming a film has been described, Step 1a and Step 3a may be interchanged. That is, step 3a, step 2a, step 1a, and step 4a are performed in this order, and this is defined as one cycle. By performing this cycle at least once, preferably a plurality of times, silicon oxide having a predetermined film thickness is formed on the wafer 200. A film can also be formed. Similarly, step 1b and step 3b may be interchanged. That is, step 3b, step 2b, step 1b, and step 4b are performed in this order, and this is defined as one cycle. By performing this cycle at least once, preferably a plurality of times, silicon having a predetermined thickness is formed on the silicon oxide film. A nitride film can also be formed.

  In the above-described embodiment, an example in which a silicon nitride film (SiN film) containing silicon (Si) as a semiconductor element is formed as a nitride film on the oxide film has been described. However, the present invention provides a nitride film on the oxide film. The present invention can also be applied to the case of forming a metal nitride film containing a metal element such as titanium (Ti), tantalum (Ta), or aluminum (Al). In this case, a metal element-containing layer is formed on the oxide film by supplying the source gas and the deposition / adsorption inhibition gas (step 1b), the residual gas is removed by purging (step 2b), and the metal element is contained by supplying the nitrogen-containing gas. By converting the layer into a metal nitride layer (step 3b) and removing the residual gas by purging (step 4b) as one cycle, this cycle is performed at least once, preferably a plurality of times, so that Then, a metal nitride film having a predetermined thickness is formed.

For example, when a titanium nitride film (TiN film) is formed as a metal nitride film containing titanium (Ti) on the oxide film, a titanium-containing layer is formed on the oxide film by supplying a source gas and a deposition / adsorption inhibition gas (step) 1b), removal of residual gas by purging (step 2b), conversion of a titanium-containing layer to a titanium nitride layer by supplying nitrogen-containing gas (step 3b), and removal of residual gas by purging (step 4b). As one cycle, this cycle is performed at least once, preferably a plurality of times to form a titanium nitride film having a predetermined thickness on the oxide film. As the raw material gas, for example, TiCl ₄ (titanium tetrachloride) gas or TDMAT (Tetrakis (dimethylamino) titanium: Ti [N (CH ₃ ) ₂ ] ₄ ) gas can be used. As the nitrogen-containing gas, NH ₃ gas can be used as in the above-described embodiment. In this case, the first gas supply system (raw material gas supply system) of the substrate processing apparatus in the above-described embodiment is configured as a titanium-containing gas supply system. Further, the processing condition is, for example, a condition within the processing condition range described in the above embodiment. The TiN film is a conductive metal nitride film.

For example, when a tantalum nitride film (TaN film) is formed as a metal nitride film containing tantalum (Ta) on the oxide film, a tantalum-containing layer is formed on the oxide film by supplying a source gas and a deposition / adsorption inhibition gas ( Step 1b), removal of residual gas by purging (Step 2b), conversion of a tantalum-containing layer to a tantalum nitride layer by supplying nitrogen-containing gas (Step 3b), removal of residual gas by purging (Step 4b), Is performed at least once, preferably a plurality of times, to form a tantalum nitride film having a predetermined thickness on the oxide film. As the source gas, for example, PET (Penta Ethoxy Tantalum: Ta (OC ₂ H ₅ ) ₅ ) gas can be used. As the nitrogen-containing gas, NH ₃ gas can be used as in the above-described embodiment. In this case, the first gas supply system (raw material gas supply system) of the substrate processing apparatus in the above-described embodiment is configured as a tantalum-containing gas supply system. Further, the processing condition is, for example, a condition within the processing condition range described in the above embodiment. The TaN film is a conductive metal nitride film.

For example, when an aluminum nitride film (AlN film) is formed as a metal nitride film containing aluminum (Al) on the oxide film, an aluminum-containing layer is formed on the oxide film by supplying a source gas and a deposition / adsorption inhibition gas ( Step 1b), removal of residual gas by purging (Step 2b), conversion of an aluminum-containing layer to an aluminum nitride layer by supplying nitrogen-containing gas (Step 3b), removal of residual gas by purging (Step 4b), Is performed at least once, preferably a plurality of times, to form an aluminum nitride film having a predetermined thickness on the oxide film. As the source gas, for example, TMA (Trimethyl-aluminum: Al (CH ₃ ) ₃ ) gas can be used. As the nitrogen-containing gas, NH ₃ gas can be used as in the above-described embodiment. In this case, the first gas supply system (raw material gas supply system) of the substrate processing apparatus in the above-described embodiment is configured as an aluminum-containing gas supply system. Further, the processing condition is, for example, a condition within the processing condition range described in the above embodiment. The AlN film is an insulating metal nitride film.

  As described above, the film forming sequence of the present embodiment can also be applied to a process of forming a conductive metal nitride film such as a TiN film or a TaN film or a process of forming an insulating metal nitride film such as an AlN film. That is, the film forming sequence of this embodiment can be applied not only when the predetermined element is a semiconductor element but also when it is a metal element. Thus, even when the present invention is applied to the formation of a metal nitride film, the same effect as that obtained when the present invention is applied to the formation of a silicon nitride film can be obtained.

  Next, examples of the present invention will be described together with comparative examples and reference examples.

In this example, an SiO film, which is a thermal oxide film, was formed as a base film on the wafer surface by wet oxidation using H ₂ O gas generated by burning O ₂ gas and H ₂ gas. Thereafter, an SiN film is formed on the SiO film as the base film by the same method as the film forming sequence (silicon nitride film forming step) of the present embodiment, and a laminated film of the formed SiO film and SiN film (hereinafter, referred to as a film stacking sequence) The leakage current density and EOT (equivalent oxide film thickness) of the SiN / SiO laminated film were measured. The wafer temperature when forming the SiO film was 800 ° C., and the film thickness was 4 nm. The film formation temperature (wafer temperature) of the SiN film was set to a temperature in the range of 600 to 900 ° C., and the film thickness was set to 8.2 to 11 nm. The SiO film was formed using an oxidation furnace different from that of the above-described substrate processing apparatus, and the SiN film was formed using an apparatus having the same configuration as the above-described substrate processing apparatus. That is, the SiO film and the SiN film were formed separately in different processing containers.

  In the comparative example, the SiN film was directly formed on the wafer without using the SiO film, and the leakage current density and EOT of the formed SiN film were measured. The SiN film was formed by the same method as the film forming sequence (silicon nitride film forming step) of this embodiment. The film formation temperature (wafer temperature) was set to a temperature in the range of 600 to 900 ° C., and the film thickness was set to 9 to 11 nm.

In the reference example, a SiO film that is a thermal oxide film is formed on the wafer surface by wet oxidation using H ₂ O gas generated by burning O ₂ gas and H ₂ gas, and the leakage current density of the formed SiO film And EOT were measured. The wafer temperature when forming the SiO film was 800 ° C., and the film thickness was 4 to 10.5 nm.

FIG. 8 is a graph showing the leakage current density and EOT of the SiN film (Example) formed through the SiO film and the SiO film (Reference Example) formed by wet oxidation. In FIG. 8, the horizontal axis indicates EOT (nm), and the vertical axis indicates the leakage current density (A / cm ² ) when a voltage of −10 V is applied. The three circles in FIG. 8 indicate, in order from the left, the SiN film deposition temperature of 900 ° C. and the SiN film thickness of 8.2 nm. In the example in which the temperature was set to 800 ° C., the SiN film thickness was set to 9.3 nm, the SiN / SiO multilayer film according to the example was set to 600 ° C., and the SiN film thickness was set to 11 nm. The measurement results of the SiN / SiO multilayer film are shown. In addition, in order from the left, the three X marks are SiO films according to a reference example with a film thickness of 7.2 nm formed at a film formation temperature of 800 ° C. The measurement results of the SiO film according to the example and the SiO film according to the reference example having a film thickness of 10.5 nm formed at a film formation temperature of 800 ° C. are shown.

FIG. 9 is a graph showing the leakage current density and EOT of the SiN film (comparative example) and the thermal oxide film (reference example) formed directly on the wafer without using the SiO film. In FIG. 9, the horizontal axis indicates EOT (nm), and the vertical axis indicates the leakage current density (A / cm ² ) when a voltage of −5 V is applied. Three triangles in FIG. 9 are, in order from the left, a SiN film according to a comparative example with a film thickness of 9 nm formed at a film formation temperature of 800 ° C., and an SiN film according to a comparative example with a film thickness of 10 nm formed at a film formation temperature of 900 ° C. The measurement result of the SiN film which concerns on the comparative example with a film thickness of 11 nm formed with the film-forming temperature of 600 degreeC is shown. Further, the x mark indicates the measurement result of the SiO film according to the reference example having a film thickness of 4 nm formed at the film forming temperature of 800 ° C.

  From FIG. 8, it can be seen that the SiN film (example) formed through the SiO film has the same EOT, that is, the same electric film thickness as that of the SiO film formed by wet oxidation (reference example). It turns out that a density becomes small. Further, FIG. 9 shows that the SiN film directly formed on the wafer without the SiO film (comparative example) shows a leakage current when viewed in the same EOT as compared with the SiO film formed by wet oxidation (reference example). It can be seen that the density increases. That is, it can be seen that the SiN film (example) formed through the SiO film can have a lower leakage current density than the SiN film (comparative example) formed directly on the wafer without using the SiO film.

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

According to one aspect of the invention,
A raw material gas containing a predetermined element is supplied into the processing container in a state where a substrate having an oxide film with a predetermined film thickness formed on the surface is accommodated in a heated processing container under a pressure atmosphere less than atmospheric pressure. Evacuating and forming a predetermined element-containing layer on the oxide film;
Supplying and exhausting a nitrogen-containing gas into the processing vessel under a heated pressure atmosphere less than atmospheric pressure to change the predetermined element-containing layer into a nitride layer;
In the meantime, a process of forming a nitride film having a predetermined thickness on the oxide film is alternately repeated with a process of supplying and exhausting an inert gas into the processing container and purging the processing container. ,
In the step of forming the predetermined element-containing layer, the source gas is supplied toward the substrate through a nozzle provided on a side of the substrate, and at that time, together with the source gas through the nozzle By supplying an inert gas or a hydrogen-containing gas toward the substrate, the flow rate of the source gas flowing in a direction parallel to the surface of the substrate is parallel to the surface of the substrate in the step of purging the inside of the processing container. A method for manufacturing a semiconductor device is provided which is larger than the flow rate of the inert gas flowing through the substrate.

  Preferably, the thickness of the oxide film is 2 nm or more and 4 nm or less.

  Preferably, the oxide film has a thickness of 2 nm.

  Preferably, the oxide film is formed in the processing container.

  Preferably, the oxide film is formed by thermally oxidizing the surface of the substrate.

  Preferably, the oxide film is formed by depositing an oxide film on the substrate.

According to another aspect of the invention,
A source gas containing silicon is supplied into the processing container in a state where a substrate having a silicon oxide film having a predetermined thickness formed on the surface is accommodated in a heated processing container under a pressure atmosphere less than atmospheric pressure. Evacuating and forming a silicon-containing layer on the silicon oxide film;
Supplying and exhausting a nitrogen-containing gas into the processing vessel under a heated pressure atmosphere less than atmospheric pressure to change the silicon-containing layer into a silicon nitride layer;
In the meantime, a process of forming a silicon nitride film having a predetermined thickness on the silicon oxide film is alternately repeated with a process of supplying and exhausting an inert gas into the processing container and purging the processing container. Have
In the step of forming the silicon-containing layer, the source gas is supplied toward the substrate through a nozzle provided on a side of the substrate, and at that time, the source gas is not discharged together with the source gas through the nozzle. By supplying the active gas or the hydrogen-containing gas toward the substrate, the flow rate of the source gas flowing in the direction parallel to the surface of the substrate is set in the direction parallel to the surface of the substrate in the step of purging the inside of the processing container. Provided is a method for manufacturing a semiconductor device in which the flow rate of flowing inert gas is greater than that.

According to yet another aspect of the invention,
A raw material gas containing a predetermined element is supplied into the processing container and exhausted in a state where the substrate is accommodated in a heated processing container under a pressure atmosphere below atmospheric pressure, and a predetermined element-containing layer is formed on the substrate. Forming a step;
Supplying and exhausting an oxygen-containing gas and a hydrogen-containing gas into the processing vessel under a heated pressure atmosphere less than atmospheric pressure to change the predetermined element-containing layer into an oxide layer;
A process of forming an oxide film having a predetermined thickness on the substrate by alternately repeating the process of supplying and exhausting an inert gas into the process container and purging the process container in the meantime, and
Supplying and exhausting the source gas into the processing vessel under a heated pressure atmosphere less than atmospheric pressure to form a predetermined element-containing layer on the oxide film;
Supplying and exhausting a nitrogen-containing gas into the processing vessel under a heated pressure atmosphere less than atmospheric pressure to change the predetermined element-containing layer into a nitride layer;
In the meantime, an inert gas is supplied into the processing vessel and exhausted to purge the inside of the processing vessel alternately, and a step of forming a nitride film having a predetermined thickness on the oxide film is repeated. In the step of forming each of the predetermined element-containing layers, the source gas is supplied toward the substrate through a nozzle provided on a side of the substrate, and at that time, the source gas is supplied through the nozzle. And supplying an inert gas or a hydrogen-containing gas toward the substrate together with the surface of the substrate in the step of purging the inside of the processing container with the flow rate of the source gas flowing in a direction parallel to the surface of the substrate. There is provided a method for manufacturing a semiconductor device in which the flow rate of the inert gas flowing in a direction parallel to the semiconductor device is larger than the flow rate.

According to yet another aspect of the invention,
A raw material gas containing a predetermined element is supplied into the processing container in a state where a substrate having an oxide film with a predetermined film thickness formed on the surface is accommodated in a heated processing container under a pressure atmosphere less than atmospheric pressure. Evacuating and forming a predetermined element-containing layer on the oxide film;
Supplying and exhausting a nitrogen-containing gas into the processing vessel under a heated pressure atmosphere less than atmospheric pressure to change the predetermined element-containing layer into a nitride layer;
In the meantime, a process of forming a nitride film having a predetermined thickness on the oxide film is alternately repeated with a process of supplying and exhausting an inert gas into the processing container and purging the processing container. ,
In the step of forming the predetermined element-containing layer, the source gas is supplied toward the substrate through a nozzle provided on a side of the substrate, and at that time, together with the source gas through the nozzle By supplying an inert gas or a hydrogen-containing gas toward the substrate, the flow rate of the source gas flowing in a direction parallel to the surface of the substrate is parallel to the surface of the substrate in the step of purging the inside of the processing container. There is provided a substrate processing method in which the flow rate of the inert gas flowing in the substrate is larger than that of the inert gas.

According to yet another aspect of the invention,
A processing container for containing a substrate;
A heater for heating the inside of the processing container;
A source gas supply system for supplying a source gas containing a predetermined element in the processing container;
A nitrogen-containing gas supply system for supplying a nitrogen-containing gas into the processing vessel;
An inert gas or hydrogen-containing gas supply system for supplying an inert gas or a hydrogen-containing gas into the processing vessel;
An exhaust system for exhausting the inside of the processing vessel;
A pressure adjusting unit for adjusting the pressure in the processing container;
The raw material gas is supplied into the processing vessel and evacuated in a state where a substrate having an oxide film with a predetermined film thickness formed on the surface is accommodated in the processing vessel under a pressure atmosphere less than atmospheric pressure. A process of forming a predetermined element-containing layer on the oxide film, and supplying and exhausting the nitrogen-containing gas into the processing vessel under a heated pressure atmosphere less than atmospheric pressure, and the predetermined element-containing layer And a process of changing the gas to a nitride layer, alternately repeating the process of supplying and exhausting the inert gas into the process vessel and purging the process vessel in the meantime, thereby forming a predetermined film on the oxide film. In the process of forming a predetermined nitride-containing layer while forming a thick nitride film, the source gas is supplied toward the substrate through a nozzle provided on the side of the substrate, and at that time, the nozzle Together with the source gas through By supplying the active gas or the hydrogen-containing gas toward the substrate, the flow rate of the source gas flowing in the direction parallel to the surface of the substrate is set in the direction parallel to the surface of the substrate in the process of purging the inside of the processing container. The heater, the raw material gas supply system, the nitrogen-containing gas supply system, the inert gas or hydrogen-containing gas supply system, the exhaust system, and the pressure adjusting unit so as to be larger than the flow rate of the inert gas flowing through And a control unit for controlling the substrate processing apparatus.

121 Controller (control unit)
200 wafer (substrate)
201 Processing chamber 202 Processing furnace 203 Reaction tube 207 Heater 231 Exhaust tube 244 APC valve (pressure adjusting unit)

Claims (3)

A raw material gas containing a predetermined element is supplied into the processing container in a state where a substrate having an oxide film with a predetermined film thickness formed on the surface is accommodated in a heated processing container under a pressure atmosphere less than atmospheric pressure. Evacuating and forming a predetermined element-containing layer on the oxide film;
Supplying and exhausting a nitrogen-containing gas into the processing vessel under a heated pressure atmosphere less than atmospheric pressure to change the predetermined element-containing layer into a nitride layer;
In the meantime, a process of forming a nitride film having a predetermined thickness on the oxide film is alternately repeated with a process of supplying and exhausting an inert gas into the processing container and purging the processing container. ,
In the step of forming the predetermined element-containing layer, the source gas is supplied toward the substrate through a nozzle provided on a side of the substrate, and at that time, together with the source gas through the nozzle By supplying an inert gas or a hydrogen-containing gas toward the substrate, the flow rate of the source gas flowing in a direction parallel to the surface of the substrate is parallel to the surface of the substrate in the step of purging the inside of the processing container. A method for manufacturing a semiconductor device, wherein the flow rate of the inert gas flowing through the substrate is larger than that of the inert gas. A raw material gas containing a predetermined element is supplied into the processing container in a state where a substrate having an oxide film with a predetermined film thickness formed on the surface is accommodated in a heated processing container under a pressure atmosphere less than atmospheric pressure. Evacuating and forming a predetermined element-containing layer on the oxide film;
Supplying and exhausting a nitrogen-containing gas into the processing vessel under a heated pressure atmosphere less than atmospheric pressure to change the predetermined element-containing layer into a nitride layer;
In the meantime, a process of forming a nitride film having a predetermined thickness on the oxide film is alternately repeated with a process of supplying and exhausting an inert gas into the processing container and purging the processing container. ,
In the step of forming the predetermined element-containing layer, the source gas is supplied toward the substrate through a nozzle provided on a side of the substrate, and at that time, together with the source gas through the nozzle By supplying an inert gas or a hydrogen-containing gas toward the substrate, the flow rate of the source gas flowing in a direction parallel to the surface of the substrate is parallel to the surface of the substrate in the step of purging the inside of the processing container. And a flow rate of the inert gas flowing through the substrate. A processing container for containing a substrate;
A heater for heating the inside of the processing container;
A source gas supply system for supplying a source gas containing a predetermined element in the processing container;
A nitrogen-containing gas supply system for supplying a nitrogen-containing gas into the processing vessel;
An inert gas or hydrogen-containing gas supply system for supplying an inert gas or a hydrogen-containing gas into the processing vessel;
An exhaust system for exhausting the inside of the processing vessel;
A pressure adjusting unit for adjusting the pressure in the processing container;
The raw material gas is supplied into the processing vessel and evacuated in a state where a substrate having an oxide film with a predetermined film thickness formed on the surface is accommodated in the processing vessel under a pressure atmosphere less than atmospheric pressure. A process of forming a predetermined element-containing layer on the oxide film, and supplying and exhausting the nitrogen-containing gas into the processing vessel under a heated pressure atmosphere less than atmospheric pressure, and the predetermined element-containing layer And a process of changing the gas to a nitride layer, alternately repeating the process of supplying and exhausting the inert gas into the process vessel and purging the process vessel in the meantime, thereby forming a predetermined film on the oxide film. In the process of forming a predetermined nitride-containing layer while forming a thick nitride film, the source gas is supplied toward the substrate through a nozzle provided on the side of the substrate, and at that time, the nozzle Together with the source gas through By supplying the active gas or the hydrogen-containing gas toward the substrate, the flow rate of the source gas flowing in the direction parallel to the surface of the substrate is set in the direction parallel to the surface of the substrate in the process of purging the inside of the processing container. The heater, the raw material gas supply system, the nitrogen-containing gas supply system, the inert gas or hydrogen-containing gas supply system, the exhaust system, and the pressure adjustment unit A control unit to control;
A substrate processing apparatus comprising: