Patent Description:
In the related art, a semiconductor manufacturing apparatus for manufac turing a semiconductor device is known as an example of a substrate processing apparatus. For example, substrate processing in which a substrate (hereinafter also referred to as a "wafer") is processed under a predetermined processing con dition by supplying a processing gas into a reaction tube is performed. Generall y, a mass flow controller (MFC) as a flow rate controller is used to supply a proc essing gas. Hereinafter, the mass flow controller may simply be referred to as a n MFC.

In recent years, various processing gases, such as gases obtained by vapor izing liquids and gases obtained by sublimating solids, have been used. It is kno wn that when these processing gases are controlled by an MFC, adiabatic expans ion occurs at a subsequent stage of the MFC.

When the processing gas re-solidifies (or re-liquefies) due to a temperatu re drop by this adiabatic expansion and reaches an interior of a reaction tube in a solid (or liquid) state (fine powder or mist state), particles may be generated. The prior art document <CIT> describes methods of producing a fuel from biogas, wherein the biogas is transported as pressurized gas in one or more pressure vessels. The prior art document <CIT> describes a method of processing biogas that includes obtaining a mobile tank containing biogas at a pressure gre ater than <NUM> psig, connecting the mobile tank to a pressure let down system, a nd depressurizing the mobile tank to remove biogas therein. The depressurizati on includes removing gas from the mobile tank using the pressure let down syst em, and introducing a warming gas into the mobile tank.

The present invention is described in the independent claims. Preferred e mbodiments are provided by the dependent claims. Some embodiments of the p resent disclosure provide a technique for supplying a processing gas without bei ng phase-changed.

According to one embodiment of the present disclosure, there is provided a technique that includes: a flow rate controller configured to control a flow rate of fluid flowing in a pipe; an adjuster configured to supply an adjustment gas to at least a downstream side of the flow rate controller; and a controller configure d to be capable of suppressing a phase change of the fluid, which is caused by a t emperature drop due to adiabatic expansion, by supplying the adjustment gas fr om the adjuster according to a difference between an internal pressure of the flo w rate controller and a pressure on the downstream side of the flow rate controll er.

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present disclosure.

Reference will now be made in detail to various embodiments, examples of which are illustrated in the accompanying drawings. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to one of ordinary skill in the art that the present disclosure may be practiced without these specific details. In other instances, well-known methods, procedures, systems, and components have not been described in detail so as not to unnecessarily obscure aspects of the various embodiments.

<FIG> and <FIG> show a vertical process furnace <NUM> used in a substrate processing apparatus which is an example of a processing apparatus. First, the outline of the operation of the substrate processing apparatus to which the present disclosure is applied will be described with reference to <FIG>. The drawings used in the following description are all schematic, and the dimensional relationship, ratios, and the like of various elements shown in figures do not always match the actual ones. Further, the dimensional relationship, ratios, and the like of various elements between plural figures do not always match each other.

When a predetermined number of substrates <NUM> as objects to be processed are transferred and charged into a boat <NUM> as a holder, the boat <NUM> is moved up by a boat elevator and is loaded into the process furnace <NUM>. In a state where the boat <NUM> is completely loaded, the process furnace <NUM> is air-tightly closed by a seal cap <NUM>. In the air-tightly closed process furnace <NUM>, according to a selected process recipe, a substrate <NUM> is processed by supplying a processing gas into the process furnace <NUM>, and discharging an atmosphere of a process chamber <NUM> by an exhaust device (not shown) through a gas exhaust pipe <NUM>. Here, the processing gas includes, for example, a precursor gas, a reaction gas, a mixture of these gases and a carrier gas, and the like. In the present disclosure, all gases that contribute to the processing of the substrate <NUM> as above are referred to as a processing gas. Further, all gases supplied to the process furnace <NUM>, which include the processing gas and an inert gas as a gas that does not contribute to the processing of the substrate <NUM>, may simply be referred to as a fluid.

Next, the process furnace <NUM> will be described with reference to <FIG> and <FIG>. A reaction tube <NUM> is installed inside a heater <NUM> which is a heating device (heating means), a manifold <NUM> made of, for example, stainless steel or the like is consecutively connected to the lower end of the reaction tube <NUM> via an O-ring <NUM> which is an airtight member, and a lower end opening (furnace opening) of the manifold <NUM> is air-tightly closed by the seal cap <NUM>, which is a cover, via an O-ring <NUM>, which is an airtight member. The process chamber <NUM> is defined and formed by at least the reaction tube <NUM>, the manifold <NUM>, and the seal cap <NUM>.

The boat <NUM> is erected on the seal cap <NUM> via a boat support table <NUM>, and the boat support table <NUM> serves as a holder for holding the boat <NUM>.

Two gas supply pipes (a first gas supply pipe <NUM> and a second gas supply pipe <NUM>) as supply paths for supplying a plurality of kinds of processing gases (here, two kinds of processing gases) are installed in the process chamber <NUM>.

On the first gas supply pipe <NUM>, a precursor source <NUM>, a first mass flow controller (hereinafter also referred to as an MFC) <NUM> which is a flow rate controller (flow rate control device), a pressure sensor <NUM>, and a valve <NUM> (hereinafter sometimes referred to as an opening/closing part) as a first opening/closing valve, are installed sequentially from the upstream. Further, a supply valve (not shown) is installed in a pipe at the upstream side of the pressure sensor <NUM> and the downstream side of the first MFC <NUM>.

A first carrier gas supply pipe <NUM> for supplying an inert gas joins on the downstream side of the opening/closing valve <NUM>. On the first carrier gas supply pipe <NUM>, a carrier gas source <NUM>, an MFC <NUM> as a flow rate control device (flow rate control means), and a valve <NUM> as an opening/closing valve, are installed sequentially from the upstream. Further, at the leading end portion of the first gas supply pipe <NUM>, a first nozzle <NUM> is installed to extend from a lower portion to a top portion along an inner wall of the reaction tube <NUM>. Gas supply holes <NUM> for supplying a gas are formed on the side surface of the first nozzle <NUM>. The first gas supply holes <NUM> are formed from a lower portion to an upper portion at equal pitches and have the same opening area. A regulator (automatic pressure control valve) may be installed instead of the MFC <NUM>.

In the present embodiment, a carrier gas (for example, a N<NUM> gas), which is an inert gas, supplied from the carrier gas source <NUM>, is used as an adjustment gas to adjust the pressure of the pressure sensor <NUM>. Details thereof will be described later. In addition, the adjustment gas (carrier gas) is supplied by a pipe <NUM> as an adjustment gas supply pipe to a supply pipe 47a between the first MFC <NUM> and the opening/closing valve <NUM> via a valve <NUM>. In the present embodiment, a structure for supplying the adjustment gas to the supply pipe 47a between the first MFC <NUM> and the opening/closing valve <NUM> via the valve <NUM> may be referred to an adjuster (hereinafter also referred to as a flow rate adjuster). That is, the adjuster is configured to include at least the carrier gas source <NUM>, the MFC <NUM>, the pipe <NUM> for supplying the inert gas as the adjustment gas to the supply pipe 47a (hereinafter also referred to as an adjustment gas supply pipe), and the valve <NUM>. In the present embodiments, although the carrier gas source <NUM> and the MFC <NUM> are configured to be integrated with a supply system that supplies an inert gas into the reaction tube <NUM>, it is not particularly limited to this form and the carrier gas source and the MFC may be individually installed as the adjuster.

Here, the first gas supply pipe <NUM>, the precursor source <NUM>, the first MFC <NUM>, the pressure sensor <NUM>, and the opening/closing valve <NUM> are collectively referred to a first gas supplier (first gas supply line). Further, the first nozzle <NUM> may be included in the first gas supplier. Further, the first carrier gas supply pipe <NUM>, the carrier gas source <NUM>, the MFC <NUM>, and the valve <NUM> may be included in the first gas supply part.

A precursor (liquid precursor, solid precursor, which is received from the precursor source <NUM>, is generated as a precursor gas (fluid of a gaseous state) in the precursor source <NUM>. This precursor gas joins with the first carrier gas supply pipe <NUM> via the first MFC <NUM> and the opening/closing valve <NUM> and is also supplied into the process chamber <NUM> via the first nozzle <NUM>. In the present embodiment, when a solid precursor is supplied into the process chamber <NUM>, the precursor source <NUM> is configured as a precursor tank <NUM>. That is, a processing gas obtained by sublimating the solid precursor in the precursor tank <NUM> is supplied into the process chamber <NUM>. Specifically, the solid precursor is placed in the precursor tank <NUM>, and the precursor tank <NUM> is heated by a sub-heater as a heating means (not shown), the heated solid precursor is sublimated, and a gaseous precursor gas is supplied into the process chamber <NUM>. When a liquid precursor is supplied into the process chamber <NUM>, the precursor source <NUM> is configured as a vaporizer. That is, the vaporizer <NUM> is heated by a sub-heater, and a precursor gas of a vaporized state (a gaseous state) in the vaporizer <NUM> is supplied into the process chamber <NUM>. A gas in which a carrier gas or an inert gas as an adjustment gas is mixed with a precursor gas is also included in the processing gas. In addition, the specific descriptions is omitted, the precursor source <NUM> also includes a precursor gas source that is gaseous at the room temperature.

The precursor tank <NUM> is configured to heat and sublimate a solid precursor to generate a precursor gas as a processing gas.

The vaporizer <NUM> is configured to heat and vaporize a precursor supplied in a liquid form to generate a precursor gas as a processing gas.

The precursor source <NUM> can also include a sub-heater (not shown). By the heating of the sub-heater, it is configured to be capable of being controlled to be equal to or higher than a temperature at which the precursor is transformed into a gaseous state. Further, the precursor source <NUM> includes a heating part for heating each of the supply pipe 47a between the first MFC <NUM> and the opening/closing valve <NUM>, a supply pipe 47b between the opening/closing valve <NUM> and the first nozzle <NUM>, the first MFC <NUM>, the opening/closing part <NUM>. In addition, it is desirable to control the temperature to be equal to or higher than the vaporization temperature of the above-mentioned precursor which is the source of a fluid.

In the second gas supply pipe <NUM>, a reaction gas source <NUM>, a third MFC <NUM>, which is a flow rate controller, and a valve <NUM>, which is an opening/closing valve, are installed sequentially from the upstream direction, and a second carrier gas supply pipe <NUM> for supplying a carrier gas joins on the downstream side of the valve <NUM>. In the second carrier gas supply pipe <NUM>, a carrier gas source <NUM>, a fourth MFC <NUM>, which is a flow rate controller, and a valve <NUM>, which is an opening/closing valve, are installed sequentially from the upstream. A second nozzle <NUM> is installed at the leading end portion of the second gas supply pipe <NUM> in parallel with the first nozzle <NUM>, and second gas supply holes <NUM>, which are supply holes for supplying a gas, are formed on the side surface of the second nozzle <NUM>. The second gas supply holes <NUM> are vertically formed at equal pitches and have the same opening area.

Here, the second gas supply pipe <NUM>, the third MFC <NUM>, the valve <NUM>, and the second nozzle <NUM> are collectively referred to as a second gas supplier (second gas supply line). The second carrier gas supply pipe <NUM>, the fourth MFC <NUM>, and the valve <NUM> may be included in the second gas supplier. Further, the reaction gas source <NUM> and the carrier gas source <NUM> may be included in the second gas supplier. A reaction gas supplied from the reaction gas source <NUM> joins with the second carrier gas supply pipe <NUM> via the third MFC <NUM> and the valve <NUM> and is supplied into the process chamber <NUM> via the second nozzle <NUM>. Needless to say, the reaction gas is included in the processing gas.

The process chamber <NUM> is connected to a vacuum pump <NUM>, which is an exhaust device (exhausting means), via the gas exhaust pipe <NUM> for exhausting a gas, and is vacuum-exhausted. A valve <NUM> as a pressure regulating valve is a second opening/closing valve that can be opened/closed to perform and stop the vacuum exhaust of the process chamber <NUM> and can adjust a pressure by adjusting the valve opening degree.

A boat rotator <NUM> is installed in the seal cap <NUM> and rotates the boat <NUM> to improve process uniformity.

Next, the fluid supply system to be managed according to the present embodiment will be specifically described with reference to <FIG>. <FIG> is an enlarged view of a main part of the supply pipe 47a for supplying the precursor gas. Herein, when the constitutions are the same as those of <FIG>, the indication thereof may be omitted.

As shown in <FIG>, the first gas supply line includes, as main parts, at least the MFC <NUM> that controls a flow rate of fluid such as a processing gas flowing through the supply pipe 47a, the pressure gauge <NUM> as a pressure sensor that detects a pressure inside the supply pipe 47a on a secondary side (output side) of the MFC <NUM>, the MFC <NUM> that supplies an inert gas as an adjustment gas to the downstream side of the supply pipe 47a from at least the MFC <NUM> at a controlled flow rate, and the opening/closing part <NUM> configured to be capable of supplying the fluid into the process chamber <NUM>. The MFC <NUM>, the MFC <NUM>, the pressure gauge <NUM>, and the opening/closing part <NUM> are electrically connected to a controller <NUM>.

The controller <NUM> corresponds to a "control part" of the present disclosure and is configured to be capable of supplying an adjustment gas via the MFC <NUM> according to a difference between an internal pressure of the MFC <NUM> and a pressure on the secondary side of the MFC <NUM>. Details thereof will be described later. The configuration of the controller <NUM> will be described later.

A Cv value of the opening/closing valve <NUM> (hereinafter also referred to as a valve characteristic value) is generally set to fall within a range of <NUM> or more and <NUM> or less. Here, the valve characteristic value (Cv value), which is defined in JIS B <NUM>:<NUM>, is a capacity coefficient indicating the ease of flow peculiar to the valve and is a value representing a capacity when a fluid flows through the valve at a certain differential pressure across the valve. In the present embodiment, it is set to a predetermined value in a range of <NUM> to <NUM>. According to such a valve characteristic value, with the opening/closing valve <NUM> shown in <FIG> kept open, by supplying the adjustment gas (inert gas) whose flow rate is adjusted by the MFC <NUM>, a pressure on the secondary side (output side) of the first MFC <NUM>, that is, a pressure P2 on the downstream side of the first MFC <NUM>, can be increased. In order to supply a large flow rate of precursor gas from the first MFC <NUM>, it is desirable that the valve characteristic value is large and the optimal valve characteristic value is <NUM>. However, regardless of the flow rate of the adjustment gas, it is possible to supply a desired precursor gas if the valve characteristic value is <NUM> or more.

Here, if the valve characteristic value is less than <NUM>, the pressure will fluctuate too much with respect to the flow rate of the adjustment gas (inert gas), which makes pressure control impossible, and as a result, the flow rate control will become unstable. Further, if the valve characteristic value is larger than <NUM>, a large amount of the adjustment gas (inert gas) is required in order to suppress re-solidification due to a temperature drop due to adiabatic expansion, and as a result, it may be difficult to control the internal pressure of the process furnace <NUM>. Further, there is a possibility that the adjustment of gas distribution in the intra-plane of the substrate <NUM> and the inter-plane of the substrate <NUM> will be disturbed (become non-uniform), which may deteriorate the quality of the substrate processing. When the valve characteristic value is <NUM> or more and <NUM> or less, by supplying an appropriate adjustment gas (inert gas), it is possible to control the internal pressure of the process furnace <NUM> while stably suppressing the adiabatic expansion and obtain a desired gas distribution within the intra-plane of the substrate <NUM> and the inter-plane of the substrate <NUM> while suppressing the generation of particles.

As shown in <FIG>, the first MFC <NUM> includes a pre-filter <NUM>, a control valve <NUM>, a first pressure sensor <NUM>, a temperature sensor <NUM>, an orifice <NUM>, a second pressure sensor <NUM>, and a controller <NUM>. Although not shown in <FIG>, the first MFC <NUM> is provided with a supply valve (not shown) that opens/closes the flow path of the supply pipe 47a, at a subsequent stage of the control valve <NUM>. The opening/closing valve (opening/closing part) <NUM> is provided in the supply pipe 47a on the downstream of the first MFC <NUM>.

The internal pressure sensor <NUM>, the temperature sensor <NUM>, and the second pressure sensor <NUM> are connected to the controller <NUM>. The opening/closing valve <NUM> is also connected to the controller <NUM>. The controller <NUM> is also connected to the controller <NUM> (see <FIG>) which will be described later. The controller <NUM> controls a flow rate of a precursor gas as a fluid flowing through a downstream side at a predetermined value. The controller <NUM> and the controller <NUM> may be implemented integrally instead of separately. In other words, the configuration may be such that control for supplying the above-mentioned adjustment gas is performed.

The first MFC <NUM> of the present embodiment is of a pressure control type that utilizes a choke flow in the orifice, and is controlled to maintain a pressure value that satisfies a choke flow condition in the orifice in the first MFC <NUM>. Specifically, when a supply pressure of the precursor gas from the precursor source <NUM> on the upstream side of the orifice is P1 and a pressure on the downstream side of the orifice is P2, the pressure P2 is maintained at a pressure value that satisfies the choke flow conditional expression"P1≥2P2" in the orifice. Further, it is configured to be capable of controlling the flow rate of the precursor gas to be kept constant with respect to the pressure fluctuation of the precursor source <NUM>.

<FIG> shows a conceptual diagram of characteristics of the first MFC <NUM>. As shown in <FIG>, a region A is a region where control is impossible due to an insufficient pressure difference (pressure P2-pressure P1), a region B is a region where control is possible, and a region C is a region where control is possible but there is a risk of particle occurrence.

With the recent miniaturization of semiconductor devices, the structure of the surface of the substrate <NUM> has become more complicated, while requirements for in-plane film thickness uniformity of a single substrate <NUM> and film thickness uniformity between substrates <NUM> have become stricter. In order to meet these requirements, precursor gas must be supplied into the process chamber <NUM> at a large flow rate as a need to supply the gas evenly to an increased surface area of the substrate <NUM> increases.

Here, as shown in <FIG>, when it is attempted to output a large flow rate of precursor gas from the MFC <NUM>, a possibility of generating particles increases (region C). This is because adiabatic expansion occurs in the subsequent stage of the MFC <NUM>, so that a temperature drop occurs. As a result, the gaseous precursor gas is phase-changed to be transformed into the original solid (or liquid), so that fine powder (or mist) is generated. Especially, when the pressure difference (pressure P2-pressure P1) is large, this fine powder (or mist) rides on the choke flow together with the precursor gas, reaches the process chamber <NUM>, and becomes a factor of particles. Therefore, the pressure difference (pressure P2-pressure P1) must be reduced (region B). Here, when a large flow rate of precursor gas is output from the MFC <NUM>, it is necessary to make an adjustment so as not to exceed the control limit value of the MFC (region A). Although this control limit value depends on the MFC, it is generally between <NUM> Torr and <NUM> Torr.

Next, the controller <NUM>, which is a control part (control means), will be described. As shown in <FIG>, the controller <NUM> is configured as a computer including a central processing unit (CPU) 41a, a random access memory (RAM) 41b, a memory 41c, and an I/O port 41d. The RAM 41b, the memory 41c, and the I/O port 41d are configured to be capable of exchanging data with the CPU 41a via an internal bus 41e. An input/output device <NUM>, which is formed of, e.g., a touch panel or the like, and an external memory <NUM> may be connected to the controller <NUM>. Further, there is installed a receiver <NUM> which is connected to a host device <NUM> via a network. The receiver <NUM> can receive information on other devices from the host device <NUM>.

The memory 41c is configured by, for example, a flash memory, a hard disk drive (HDD), or the like. A control program for controlling operations of a substrate processing apparatus, a process recipe, a correction recipe, etc. in which sequences and conditions of substrate processing to be described later are written, are readably stored in the memory 41c. The process recipe and the correction recipe function as programs for causing the controller <NUM> to execute each sequence in a substrate processing process and a characteristic checking process performed in a substrate processing mode, to obtain an expected result. When the term "program" is used herein, it may indicate a case of including the process recipe and the correction recipe only, a case of including the control program only, or a case of including all the process recipe, the correction recipe, and the control program. The RAM 41b is configured as a memory area (work area) in which a program or data read by the CPU 41a is temporarily stored. In the present embodiment, the memory 41c stores characteristic data including the control limit range of the flow rate controller (especially the MFC <NUM>) shown in <FIG>, and characteristic data including the vapor pressure curves for precursors such as various solid precursors and liquid precursors shown in <FIG>. Further, threshold values (for example, the pressure difference (P1-P2) and the valve characteristic value), which are set in advance, are stored in the memory 41c. Further, the I/O port 41d is connected to an elevating member, a heater, a mass flow controller, each MFC, each valve, and the like.

The controller <NUM>, which is the control part, performs the flow rate adjustment of the MFCs installed in the substrate processing apparatus, the opening/closing operation of the valves, the temperature adjustment of the heater, the actuating and stopping operation of the vacuum pump, the rotation speed adjustment of the boat rotator, the elevating operation control of the boat elevator, and so on. Further, in the present embodiment, the controller <NUM> acquires characteristic data shown in <FIG>, which are stored in the memory 41c, and threshold values of a pressure difference (P1-P2) that is set in advance and a valve characteristic value, and controls the operations of the MFC <NUM>, the MFC <NUM>, the pressure gauge <NUM>, the valve <NUM>, etc. based on these characteristic data and threshold values.

Then, the controller <NUM> causes the carrier gas source <NUM> to supply the adjustment gas whose flow rate is adjusted by the MFC <NUM> to the supply pipe 47a on the downstream side of the first MFC <NUM>, and adjusts a pressure difference between the internal pressure P1 of the first MFC <NUM> and the pressure P2 on the downstream side of the first MFC <NUM> based on the threshold value of the pressure difference (P1-P2) so as not to exceed the control limit value of the first MFC <NUM>. Therefore, since a precursor gas flowing through the supply pipe 47a from the precursor source <NUM> can be set to the conditions of (iii) of <FIG>, the phase change of the precursor gas can be suppressed.

The controller <NUM> is not limited to being configured as a dedicated computer, and may be configured as a general-purpose computer. For example, the controller <NUM> of the present embodiment can be configured by preparing the external memory (for example, a semiconductor memory such as a USB memory or a memory card) <NUM> that stores the aforementioned program and installing the program on the general-purpose computer by using the external memory <NUM>. A means for supplying the program to the computer is not limited to a case of supplying the program via the external memory <NUM>. For example, the program may be installed on the computer using communication means such as the Internet or a dedicated line, instead of using the external memory <NUM>. The memory 41c or the external memory <NUM> is configured as a non-transitory computer-readable recording medium. Hereinafter, the memory 41c and the external memory <NUM> may be generally and simply referred to as a "recording medium. " When the term "recording medium" is used herein, it may indicate a case of including the memory 41c only, a case of including the external memory <NUM> only, or a case of including both the memory 41c and the external memory <NUM>.

Next, an example of processing a substrate will be described. Here, as an example of a process of manufacturing a semiconductor device, a cycle process in which a source gas (precursor gas) and a reactant gas (reaction gas) are alternately supplied into the process chamber will be described. In the present embodiment, an example of forming a film on a substrate will be described.

In the process of the present embodiment, a film is formed on a substrate <NUM> by performing a cycle a predetermined number of times (one or more times), the cycle including non-simultaneously performing a step of supplying a precursor gas to the substrate <NUM> in the process chamber <NUM> (film-formation step <NUM>: step S3 in <FIG>), a purge step of removing the precursor gas (residual gas) from the process chamber <NUM> (film-forming step <NUM>: step S4 in <FIG>), a step of supplying a nitrogen-containing gas to the substrate <NUM> in the process chamber <NUM> (film-forming step <NUM>: step S5 in <FIG>), and a purge step of removing the nitrogen-containing gas (residual gas) from the process chamber <NUM> (film-forming step <NUM>: step S6 in <FIG>).

First, as described above, the substrate <NUM> is charged into the boat <NUM> and loaded into the process chamber <NUM> (step S1 in <FIG>). At this time, after the boat <NUM> is loaded into the process chamber <NUM>, the internal pressure and internal temperature of the process chamber <NUM> are adjusted (step S2 in <FIG>). Next, four steps of film-forming steps <NUM> to <NUM> are sequentially executed. Each step will be described in detail below.

In film-forming step <NUM>, first, a precursor gas is adsorbed on the surface of the substrate <NUM>. Specifically, in the first gas supply line, with the opening/closing valve <NUM> opened, the precursor gas generated in the precursor source <NUM> is supplied into the process chamber <NUM> by the first MFC <NUM>.

Here, in the present embodiment, when the pressure difference (P1-P2) falls within a preset range (that is, the state of region B), the controller <NUM> causes the precursor gas generated in the precursor source <NUM> to be supplied into the process chamber <NUM> by the first MFC <NUM> without supplying an adjustment gas to the supply pipe 47a.

On the other hand, when the pressure difference (P1-P2) is out of the preset range (that is, the state of region C), the controller <NUM> causes an adjustment gas whose flow rate is controlled by the MFC <NUM> to be supplied to the supply pipe 47a in order to operate the first MFC <NUM> in the state of region B shown in <FIG>. Then, when the pressure difference (P1-P2) falls within the preset range, the controller <NUM> stops the supply of the adjustment gas and causes a mixture of the precursor gas generated in the precursor source <NUM> and the adjustment gas to be supplied into the process chamber <NUM> by the first MFC <NUM>. In addition, it may be possible to supply a small amount of the adjustment gas which does not affect the film formation without stopping the supply of the adjustment gas.

Further, a threshold value as a first predetermined value may be determined within a preset range (a controllable range of the first MFC <NUM>). In this case, the controller <NUM> can determine the flow rate supply time of the adjustment gas as a time required until the difference between the internal pressure of the first MFC <NUM> and the pressure on the secondary side of the first MFC <NUM> becomes equal to or less than the preset first predetermined value. As a result, the first MFC <NUM> in the region C can be changed to the state of region B. Then, the mixture of the precursor gas generated in the precursor source <NUM> and the adjustment gas is supplied into the process chamber <NUM> by the first MFC <NUM>. For example, the first predetermined value is set to a lower limit pressure that prevents a phase change due to adiabatic expansion. Further, a value with a slight margin from the lower limit pressure may be used.

The above-described control for transitioning the first MFC <NUM> from the state of region C to the state of region B is performed by sequentially executing the four steps of film-forming steps <NUM> to <NUM> and must be completed until the next film-forming step <NUM> proceeds. According to the present embodiment, it is possible to supply a constant flow rate controlled by the MFC <NUM>, so that it is easy to complete the control in advance until the next film-forming step <NUM> proceeds.

In film-forming step <NUM>, the opening/closing valve <NUM> of the first gas supply pipe <NUM> and the valve <NUM> of the first carrier gas supply pipe <NUM> are closed to stop the supply of the precursor gas and the carrier gas. With the valve <NUM> of the gas exhaust pipe <NUM> kept open, the process furnace <NUM> is exhausted to <NUM> Pa or less by the vacuum pump <NUM> to remove the residual precursor gas from the process chamber <NUM>. At this time, when an inert gas such as a N<NUM> gas used as a carrier gas is supplied to the process furnace <NUM>, the effect of removing the residual precursor gas is further enhanced.

In film-forming step <NUM>, a nitrogen-containing gas and a carrier gas are allowed to flow. First, the valve <NUM> installed in the second gas supply pipe <NUM> and the valve <NUM> installed in the second carrier gas supply pipe <NUM> are both opened, the nitrogen-containing gas whose flow rate is adjusted by the third MFC <NUM> from the second gas supply pipe <NUM> is mixed with the carrier gas whose flow rate is adjusted by the fourth MFC <NUM> from the second carrier gas supply pipe <NUM>, and a mixture of the nitrogen-containing gas and the carrier gas is supplied into the process chamber <NUM> from the second gas supply holes <NUM> of the second nozzle <NUM> and exhausted from the gas exhaust pipe <NUM>. By supplying the nitrogen-containing gas, a film on a base film of the substrate <NUM> reacts with the nitrogen-containing gas and a nitride film on the substrate <NUM> is formed.

After the nitride film is formed, in film-forming step <NUM>, the valves <NUM> and <NUM> are closed, the process chamber <NUM> is vacuum-exhausted by the vacuum pump <NUM> as the exhaust device to remove the nitrogen-containing gas remaining after contributing to the film formation. At this time, when an inert gas such as a N<NUM> gas used as a carrier gas is supplied into the process chamber <NUM>, the effect of removing the residual nitrogen-containing gas from the process chamber <NUM> is enhanced.

Then, with the above-described film-forming steps <NUM> to <NUM> as one cycle, a film having a predetermined film thickness can be formed on the substrate <NUM> by performing the cycle of film-forming steps <NUM> to <NUM> a predetermined number of times in step S7 in <FIG>. In the present embodiment, film-forming steps <NUM> to <NUM> are repeated a plurality of times.

After the above-described film-forming process is completed, in step S8 in <FIG>, the pressure of the process chamber <NUM> is returned to the normal pressure (atmospheric pressure). Specifically, for example, an inert gas such as a N<NUM> gas is supplied into the process chamber <NUM> and is exhausted. As a result, the process chamber <NUM> is purged with the inert gas to remove a gas and the like remaining in the process chamber <NUM> from the process chamber <NUM> (inert gas purge). Thereafter, the atmosphere of the process chamber <NUM> is substituted with the inert gas (inert gas substitution), and the pressure of the process chamber <NUM> is returned to the normal pressure (atmospheric pressure). Then, in step S9 in <FIG>, when the substrate <NUM> is unloaded from the process chamber <NUM>, the substrate processing according to the present embodiment is completed.

<FIG> shows a vapor pressure curve of a solid precursor as an example of the precursor and a state transition of a fluid (in this case, a precursor gas obtained by sublimating a solid precursor). The present embodiment will be described in detail with reference to <FIG>.

In <FIG>, (i) shows a state of the precursor gas when it is supplied from the precursor source <NUM> to the first MFC <NUM>. In this state, if only sublimation is required, the sub-heater can be used to raise the temperature, but the higher the temperature, the higher the risk of solidification and corrosion. Therefore, the temperature is controlled so as not to be set to an excessively high temperature and to be close to the sublimation temperature (near the vapor pressure curve).

In <FIG>, (ii) shows a result when the first MFC <NUM> outputs the precursor gas under the condition of region C shown in <FIG>. In <FIG>, in the present embodiment, when a large flow rate of precursor gas is output from the first MFC <NUM>, (iii) shows a result when the pressure difference (P1-P2) is adjusted with an adjustment gas so as not to exceed the control limit value of the first MFC (so as not to enter the region A shown in <FIG>). That is, this is the result when the first MFC <NUM> outputs the precursor gas under the condition of region B shown in <FIG> and the pressure difference (P1-P2) is adjusted to be near the control limit value of the first MFC.

Here, when comparing (ii) and (iii) in <FIG>, the state transition in (iii) in <FIG> is much smaller than that of (ii) in <FIG>. In other words, it can be seen that the state transition due to the adiabatic expansion when the precursor gas is discharged from the first MFC <NUM> is reduced. This is because the adjustment gas is supplied to the downstream side (secondary side) of the first MFC <NUM> to increase the pressure P2 on the downstream side (secondary side) of the first MFC <NUM> before supplying the precursor gas into the process chamber <NUM>, thereby reducing the value of the pressure difference (P1-P2) to reduce an effect by the adiabatic expansion.

In this way, according to the present embodiment, the controller <NUM> can detect in advance a condition in which a phase change (Vapor-Solid) of the gaseous precursor gas ((i) in <FIG>) is generated by a temperature drop due to the adiabatic expansion when a large flow rate is discharged from the MFC <NUM>, and can adjust the pressure difference (P1-P2) such that the phase change (Vapor-Solid) is not generated even if the temperature drops due to the adiabatic expansion. For example, the threshold value (first set value) may be set to a value near the lower limit pressure that prevents the phase change due to the adiabatic expansion, and the controller <NUM> may compare the pressure difference (P1-P2) with the threshold value.

Since the present embodiment has the configuration including the first MFC <NUM> that controls the flow rate of precursor gas flowing through the supply pipe 47a, the pressure gauge <NUM> that detects the pressure on the secondary side of the first MFC <NUM>, the supplier that supplies the adjustment gas (inert gas) to at least the secondary side (downstream side) of the first MFC <NUM>, and the controller <NUM> configured to be capable of suppressing the phase change of the precursor gas by causing the adjustment gas to be supplied from the adjuster according to the difference between the internal pressure P1 of the first MFC <NUM> and the pressure P2 on the secondary side (downstream side) of the first MFC <NUM>, it is possible to supply a large flow rate of precursor gas into the process chamber <NUM>. Therefore, it is possible to improve the step coverage and reproducibility of a film formed on the surface of the substrate <NUM>, thereby enhancing the in-plane film thickness uniformity of the substrate and the film thickness uniformity between substrates.

Further, in the present embodiment, by supplying the adjustment gas from the adjuster according to the difference between the internal pressure P1 of the first MFC <NUM> and the pressure P2 on the secondary side (downstream side) of the first MFC <NUM>, the effect of adiabatic expansion due to the discharge of a large flow rate of precursor gas from the first MFC <NUM> can be suppressed, so that it is possible to suppress the re-solidification (or re-liquefaction) of the precursor gas. In particular, since the controller <NUM> can minimize the pressure difference (P1-P2) so as not to exceed the control limit value of the first MFC <NUM>, it possible to continuously supply a large flow rate of gas into the process chamber <NUM>.

Further, flush supply can also be achieved by increasing the capacity of the precursor source <NUM> or increasing the diameter of the orifice <NUM> of the flow path. Further, in the present embodiment, it is possible to dispose a container that stores the processing gas between the MFC <NUM> and the opening/closing valve <NUM>, whereby the first nozzle <NUM> can discharge the precursor gas into a decompressed process chamber <NUM>. Therefore, it is possible to perform flash supply for improving the in-plane film thickness uniformity of the substrate and the film thickness uniformity between substrates.

<FIG> shows a modification of <FIG>. A difference from <FIG> is that a heater <NUM> for heating an inert gas (carrier gas) as an adjustment gas is further installed. The other configuration is the same as the fluid supply system shown in <FIG>. For the same components as those of <FIG>, the indication thereof are omitted in <FIG>. Thus, herein, the configuration relating to the heater <NUM> will be described.

As shown in <FIG>, it is configured to include the heater <NUM> for heating the inert gas (carrier gas), as the adjustment gas, to a temperature equal to or higher than a sublimation temperature or a vaporization temperature of the fluid to be supplied into the process chamber <NUM>. It is configured such that the fluid supplied to the process chamber <NUM> is heated by being mixed with the adjustment gas heated by the heater <NUM>. With this configuration, it is possible to directly contact the adjustment gas with respect to the fluid, so that the temperature of the fluid can be increased more efficiently than installing a heater or the like as a heating means on the outside of the pipe.

For example, since the state in <FIG> can be shifted to the right, it is possible to make the solid state in <FIG> a vapor state. Specifically, the fluid supplied to the process chamber <NUM> is heated by heat conduction with the adjustment gas heated by the heater <NUM>, so that a temperature increasing effect by heating of the fluid is expected in addition to suppressing a temperature decrease by the adiabatic expansion by the adjustment gas. Thereby, it becomes possible to suppress re-solidification (or re-liquefaction) of the fluid (particularly the precursor gas).

Particularly, the above effect by the adjustment gas is exerted by being mixed with the fluid supplied into the processing chamber <NUM> in the pipe on the downstream side, which is directly connected to the flow rate controller such as the first MFC. Therefore, in the configuration shown in <FIG>, the effects of suppressing the temperature decrease due to adiabatic expansion by the adjustment gas and increasing the temperature by heating the fluid are most expected.

Although the embodiments of the present disclosure have been specifically described above, the present disclosure is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present disclosure.

For example, in the present embodiment, the pipe <NUM> and the valve <NUM> are installed as components of the flow rate adjuster, but the present disclosure is not limited thereto. Although not shown, the opening/closing valve <NUM> may be installed in the pipe 47b, that is, between the MFC <NUM> and the nozzle <NUM> (desirably in the vicinity of the nozzle <NUM>). In this case, since the inert gas can be supplied as the adjustment gas to the downstream side of the first MFC <NUM> by the inert gas source <NUM> and the MFC <NUM>, the pipe <NUM> and the valve <NUM> in the present embodiment can be omitted. On the other hand, separately (independently) from the inert gas source <NUM> and the MFC <NUM>, the inert gas source, the MFC, the valves, the pipes, etc. as an adjustment gas supplier may be directly connected to the downstream side of the first MFC <NUM>.

Further, a pressure gauge may be installed in the supply pipe 47a on the upstream side of the first MFC <NUM> to measure the supply pressure P1 of the precursor gas from the precursor source <NUM>. In this case, the controller <NUM> causes the adjustment gas whose flow rate is controlled by the MFC <NUM> to be supplied to the supply pipe 47a in order to operate the first MFC <NUM> in the state of region B shown in <FIG>. Then, when the pressure difference (P1-P2) is within a preset range (or is a preset threshold value (first predetermined value)), the controller <NUM> stops the supply of the adjustment gas, and causes the mixture of the precursor gas and the adjustment gas to be supplied into the process chamber <NUM> with the control valve <NUM> kept open. As a result, since adjustment can be made to the condition of region B of the first MFC <NUM> so as not to exceed the control limit value of the MFC, it is possible to supply a large flow rate of precursor gas into the process chamber <NUM>. As a result, since the precursor gas can be spread over the surface of the substrate <NUM>, it is possible to improve the in-plane film thickness uniformity of the single substrate <NUM> and the film thickness uniformity between substrates <NUM>.

Further, although the first MFC <NUM> is of a pressure control type using the choke flow in the orifice, it may be a heat control type MFC. The heat control type is a method of controlling a flow rate in response to a change in temperature of two temperature detectors installed in a flow path. Specifically, the heat control type is to separate the gas flow path into a bypass line and a sensor line, detect the change in temperature from two temperature sensors installed in the upstream and downstream sides of the sensor line, and control a flow rate Q based on the detected change. Herein, the total flow rate Q is sensor flow Q1+bypass flow Q2. When a temperature of the upstream-side temperature sensor is T1, a temperature of the downstream-side temperature sensor is T2, and a division ratio k is Q2/Q1, the flow rate Q is expressed as Q=k×(T1-T2).

Even when this heat control-type MFC is adopted, the controller <NUM> can check whether or not the pressure difference (P1-P2) is within the preset range. If it is out of the range, the controller <NUM> can cause the adjustment gas to be supplied to the supply pipe 47a in order to operate the heat control-type MFC in the state of region B shown in <FIG>. That is, the heat control-type MFC is applicable to the present disclosure.

Regardless of the valve characteristic value of the opening/closing valve <NUM>, the pressure P2 on the downstream side of the MFC <NUM> can be increased by closing the opening/closing valve <NUM>. Specifically, when the pressure difference (P1-P2) is out of the preset range (that is, in the state of region C) and even if the conductance value of the opening/closing valve <NUM> is not in a range of <NUM> to <NUM>, by closing the opening/closing valve <NUM>, the controller <NUM> causes the adjustment gas whose flow rate is controlled by the MFC <NUM> to be supplied into the supply pipe 47a, to increase the downstream side pressure P2 of the first MFC <NUM>. However, if the valve characteristic value is high, a large amount of inert gas is required. If the valve characteristic value is too low, the precursor gas flow rate becomes small, which may lead to a possibility that a desired precursor gas flow rate cannot be supplied into the process chamber <NUM>. In particular, it is difficult to apply it when the supply time of the precursor gas is short in a cyclic process or the like.

Further, for example, in the above-described embodiments, as the film-forming process performed by the substrate processing apparatus, the solid precursor as the precursor gas is used and it is configured such that the precursor gas is generated by heating and sublimating the solid precursor. Although the case in which the nitride film is formed on the substrate <NUM> by using the nitrogen-containing gas as the reactant (reactive gas) and supplying these gases alternately, is taken as an example, the present disclosure is not limited thereto.

Herein, as the solid precursor, there is a solid precursor chemical substance, particularly inorganic solid precursor metal or a semiconductor precursor, and for example, HfCl<NUM>, ZrCl<NUM>, AlCl<NUM>, MoO<NUM>Cl<NUM>, or MoCl<NUM> or SiI<NUM> is adopted as the solid precursor.

Further, it is configured to heat and vaporize a precursor supplied in a liquid form to generate a precursor gas. Examples of the liquid precursor may include chlorosilane-based gases such as a monochlorosilane (SiH<NUM>Cl, abbreviation: MCS) gas, a dichlorosilane (SiH<NUM>Cl<NUM>, abbreviation: DCS) gas, a trichlorosilane (SiHCl<NUM>, abbreviation: TCS) gas, a tetrachlorosilane (SiCl<NUM>, abbreviation: STC) gas, a hexachlorodisilane gas (Si<NUM>Cl<NUM>, abbreviation: HCDS) gas, and an octachlorotrisilane (Si<NUM>Cl<NUM>, abbreviation: OCTS) gas. Examples of the precursor gas may include fluorosilane-based gases such as a tetrafluorosilane (SiF<NUM>) gas and a difluorosilane (SiH<NUM>F<NUM>) gas, bromosilane-based gases such as a tetrabromosilane (SiBr<NUM>) gas and a dibromosilane (SiH<NUM>Br<NUM>) gas, and iodosilane-based gases such as a tetraiodosilane (SiI<NUM>) gas and a diiodosilane (SiH<NUM>I<NUM>) gas. Examples of the precursor gas may also include aminosilane-based gases such as a tetrakis(dimethylamino)silane (Si[N(CH<NUM>)<NUM>]<NUM>, abbreviation: 4DMAS) gas, a tris(dimethylamino)silane (Si[N(CH<NUM>)<NUM>]<NUM>H, abbreviation: 3DMAS) gas, a bis(diethylamino)silane (Si[N(C<NUM>H<NUM>)<NUM>]<NUM>H<NUM>, abbreviation: BDEAS) gas, and a bis(tert-butylamino)silane (SiH<NUM>[NH(C<NUM>H<NUM>)]<NUM>, abbreviation: BTBAS ) gas. Further, as the precursor gas, for example, an organic-based silane precursor gas such as a tetraethoxysilane (Si(OC<NUM>H<NUM>)<NUM>, abbreviation: TEOS) gas can also be used. One or more of these gases can be used as the precursor gas. That is, the precursor gas can also include precursors that are stored in a liquid form by pressurization or cooling.

As the nitrogen-containing gas, one or more selected from the group of a nitrous oxide (N<NUM>O) gas, a nitric oxide (NO) gas, a nitrogen dioxide (NO<NUM>) gas, an ammonia (NH<NUM>) gas, and the like can be used.

Further, the reactant is not limited to the nitrogen-containing gas, and other types of thin films may be formed using gases that react with the source to perform film processing. Furthermore, the film-forming process may be performed using three or more kinds of processing gases.

Further, for example, in each of the above-described embodiments, the film-forming process in the semiconductor device is taken as an example of the process performed by the substrate processing apparatus, but the present disclosure is not limited thereto. The technique of the present disclosure can be applied to all processes performed by exposing an object on which a pattern with a high aspect ratio (that is, the depth is greater than the width) is formed to a vaporized gas. That is, in addition to the film-forming process, the process performed by the substrate processing apparatus may be a process of forming an oxide film or a nitride film, or a process of forming a film containing metal. Further, the specific contents of the substrate processing is irrelevant, and the present disclosure can be suitably applied not only to the film-forming process but also to other substrate processing such as annealing, oxidation, nitridation, diffusion, lithography, and the like.

Further, the present disclosure can also be suitably applied to other substrate processing apparatuses such as an annealing apparatus, an oxidation apparatus, a nitridation apparatus, an exposure apparatus, a coating apparatus, a drying apparatus, a heating apparatus, a plasma processing apparatus, and the like. Further, the present disclosure may be suitably applied to a mixture of these apparatuses.

Further, in the present embodiments, although the semiconductor manufacturing process has been described, the present disclosure is not limited thereto. For example, the present disclosure can also be applied to substrate processing such as a liquid crystal device manufacturing process, a solar cell manufacturing process, a light emitting device manufacturing process, a glass substrate processing process, a ceramic substrate processing process, and a conductive substrate processing process.

Further, a portion of the configuration of any embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of any embodiment. Further, it is also possible to add, delete, or replace a portion of the configuration of each embodiment with another configuration.

Further, in the above-described embodiments, an example of using the N<NUM> gas as the inert gas has been described, but the present disclosure is not limited thereto. For example, a rare gas such as an Ar gas, a He gas, a Ne gas, and a Xe gas may be used as the inert gas. However, in this case, it is necessary to prepare a rare gas source. Further, it is necessary to connect this rare gas source to the first gas supply pipe <NUM> so that the rare gas can be introduced.

According to the present disclosure in some embodiments, it is possible to supply a processing gas without being phase-changed.

Claim 1:
A fluid supply system comprising:
a flow rate controller (<NUM>) that is installed on a pipe (47a) such that the pipe (47a) extends via the flow rate controller (<NUM>), and the flow rate controller (<NUM>) is configured to control a flow rate of fluid flowing in the pipe (47a);
an adjuster (<NUM>, <NUM>, <NUM>, <NUM>) configured to supply an adjustment gas to at least a downstream side of the flow rate controller (<NUM>);
a first pressure sensor (<NUM>) configured to detect a first pressure in a first portion of the pipe (47a), the first portion being located in the flow rate controller (<NUM>);
a second pressure sensor (<NUM>) configured to detect a second pressure in a second portion of the pipe (47a), the second portion being located on the downstream side of the flow rate controller (<NUM>); and
a controller (<NUM>) configured to be capable of suppressing a phase change of the fluid, which is caused by a temperature drop due to adiabatic expansion, by supplying the adjustment gas from the adjuster (<NUM>, <NUM>, <NUM>, <NUM>) according to a difference between the first pressure and the second pressure.