Method of processing substrate, substrate processing apparatus, recording medium, and method of manufacturing semiconductor device

There is provided a technique that includes: forming a film containing a main element, carbon and nitrogen on a pattern formed on a surface of a substrate by performing a cycle a predetermined number of times, the cycle including non-simultaneously performing: (a) forming a first layer containing the main element by supplying a precursor, which contains the main element constituting the film to be formed, to the substrate having the pattern; and (b) forming a second layer containing the main element, carbon and nitrogen by supplying a first reactant, which contains carbon and nitrogen, to the substrate so that a substance obtained by decomposing a portion of the first reactant is adsorbed on the first layer.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2017-053328, filed on Mar. 17, 2017, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a method of manufacturing a semiconductor device, a substrate processing apparatus, and a recording medium.

BACKGROUND

As an example of processes of manufacturing a semiconductor device, a process of forming a film on a substrate is often carried out by non-simultaneously supplying a precursor and a reactant to the substrate.

When a film is formed on a substrate having a pattern formed on a surface of the substrate, there may occur a phenomenon that the thickness of a film to be formed becomes smaller (hereinafter, this phenomenon is also referred to as a “film thickness drop phenomenon”) when compared with when a film is formed on a substrate having no pattern formed on the surface of the substrate.

SUMMARY

Some embodiments of the present disclosure provide a technique capable of suppressing occurrence of a film thickness drop phenomenon when a film is formed on a substrate having a pattern formed on a surface of the substrate.

According to one embodiment of the present disclosure, there is provided a technique that includes: forming a film containing a main element, carbon and nitrogen on a pattern formed on a surface of a substrate by performing a cycle a predetermined number of times, the cycle including non-simultaneously performing: (a) forming a first layer containing the main element by supplying a precursor, which contains the main element constituting the film to be formed, to the substrate having the pattern; and (b) forming a second layer containing the main element, carbon and nitrogen, by supplying a first reactant, which contains carbon and nitrogen to the substrate so that a substance obtained by decomposing a portion of the first reactant is adsorbed on the first layer, wherein in (b), the first reactant is supplied until a density of an adsorption layer of the substance formed on each of at least an upper surface, a side surface and a lower surface of the pattern is equalized.

DETAILED DESCRIPTION

One Embodiment of the Present Disclosure

One embodiment of the present disclosure will be described as below with reference toFIGS.1to5.

(1) Configuration of the Substrate Processing Apparatus

As illustrated inFIG.1, a processing furnace202includes a heater207as a heating means (heating mechanism). The heater207has a cylindrical shape and is supported by a retaining plate so as to be vertically installed. The heater207functions as an activation mechanism (an excitation part) configured to thermally activate (excite) a gas.

A reaction tube203is disposed inside the heater207to be concentric with the heater207. The reaction tube203is made of a heat resistant material such as, quartz (SiO2), silicon carbide (SiC) or the like and has a cylindrical shape with its upper end closed and its lower end opened. A process chamber201is formed in a hollow cylindrical portion of the reaction tube203. The process chamber201is configured to accommodate wafers200as substrates.

Nozzles249aand249bare installed in the process chamber201so as to penetrate a sidewall of the lower portion of the reaction tube203. Gas supply pipes232aand232bare connected to the nozzles249aand249b, respectively.

Mass flow controllers (MFCs)241aand241b, which are flow rate controllers (flow rate control parts), and valves243aand243b, which are opening/closing valves, are installed to the gas supply pipes232aand232b, respectively, sequentially from upstream sides of the gas supply pipes232aand232b. Gas supply pipes232cand232d, which supply an inert gas, are connected to the gas supply pipes232aand232b, respectively, at downstream side of the valves243aand243b. MFCs241cand241d, and valves243cand243dare installed to the gas supply pipes232cand232d, respectively, sequentially from upstream sides of the gas supply pipes232cand232d.

As illustrated inFIG.2, the nozzles249aand249bare respectively disposed in a space with an annular plan-view shape between the inner wall of the reaction tube203and the wafers200such that the nozzle249aextends upward along a stacking direction of the wafers200from a lower portion of the inner wall of the reaction tube203to an upper portion of the inner wall of the reaction tube203. That is, the nozzles249aand249bare installed at a lateral side of a wafer arrangement region in which the wafers200are arranged, namely in a region which horizontally surrounds the wafer arrangement region, so as to extend along the wafer arrangement region. Gas supply holes250aand250bfor supplying a gas are formed on the side surfaces of the nozzles249aand249b, respectively. The gas supply holes250aand250bare opened toward the center of the reaction tube203so as to allow a gas to be supplied toward the wafers200. The gas supply holes250aand250bmay be formed in a plural number between the lower portion of the reaction tube203and the upper portion of the reaction tube203.

A halosilane-based precursor gas, which contains silicon (Si) as a main element and a halogen element constituting a film to be formed, is supplied as a precursor (precursor gas) from the gas supply pipe232ainto the process chamber201via the MFC241a, the valve243aand the nozzle249a. The precursor gas refers to a gaseous precursor, for example, a gas obtained by vaporizing a precursor which remains in a liquid state under a room temperature and an atmospheric pressure, or a precursor which remains in a gas state under the room temperature and the atmospheric pressure. The halogen element may include chlorine (Cl), fluorine (F), bromine (Br), iodine (I), and the like. As the halosilane-based gas, it may be possible to use, for example, a chlorosilane-based gas containing Cl. As the chlorosilane-based gas, it may be possible to use, for example, hexachlorodisilane (Si2Cl6, abbreviation: HCDS) gas.

An amine-based gas, which contains carbon (C) and nitrogen (N), is supplied as a first reactant (first reaction gas) from the gas supply pipe232binto the process chamber201via the MFC241b, the valve243b, and the nozzle249b. The amine-based gas is composed of three elements of N, C and H. As the amine-based gas, it may be possible to use, for example, triethylamine ((C2H5)3N, abbreviation: TEA) gas.

An oxidizing gas (oxidizing agent), which is a gas containing oxygen (O), is supplied as a second reactant (second reaction gas) from the gas supply pipe232binto the process chamber201via the MFC241b, the valve243b, and the nozzle249b. As the oxidizing gas, it may be possible to use, for example, oxygen (O2) gas.

An inert gas is supplied from the gas supply pipes232cand232dinto the process chamber201via the MFCs241cand241d, the valves243cand243d, the gas supply pipes232aand232b, and the nozzles249aand249b. As the inert gas, it may be possible to use, for example, nitrogen (N2) gas.

A precursor supply system mainly includes the gas supply pipe232a, the MFC241a, and the valve243a. Each of first and second reactant supply systems mainly includes the gas supply pipe232b, the MFC241b, and the valve243b. An inert gas supply system mainly includes the gas supply pipes232cand232d, the MFCs241cand241d, and the valves243cand243d.

One or all of various kinds of supply systems described above may be configured as an integrated supply system248in which the valves243ato243d, the MFCs241ato241d, and the like are integrated. The integrated supply system248is connected to each of the gas supply pipes232ato232dand is configured such that the supply operations of various kinds of gases into the gas supply pipes232ato232d, i.e., the opening/closing operation of the valves243ato243d, the flow rate adjusting operation by the MFCs241ato241d, and the like, are controlled by a controller121which will be described later. The integrated supply system248is configured as an integral type or division type integrated unit, and is detachable from the gas supply pipes232ato232dand the like on an integrated unit basis such that the maintenance, replacement, expansion or the like of the integrated supply system248can be performed on an integrated unit basis.

An exhaust pipe231configured to exhaust the internal atmosphere of the process chamber201is installed in the reaction tube203. A vacuum pump246as a vacuum exhaust device is connected to the exhaust pipe231via a pressure sensor245as a pressure detector (pressure detection part) which detects the internal pressure of the process chamber201and an auto pressure controller (APC) valve244as a pressure regulator (pressure regulation part). The APC valve244is configured so that the vacuum exhaust and the vacuum exhaust stop of the interior of the process chamber201can be performed by opening and closing the APC valve244while operating the vacuum pump246and so that the internal pressure of the process chamber201can be adjusted by adjusting the opening degree of the APC valve244based on the pressure information detected by the pressure sensor245while operating the vacuum pump246. An exhaust system mainly includes the exhaust pipe231, the APC valve244and the pressure sensor245. The vacuum pump246may be regarded as being included in the exhaust system.

A seal cap219, which serves as a furnace opening cover configured to hermetically seal a lower end opening of the reaction tube203, is installed under the reaction tube203. The seal cap219is made of a metal material such as, stainless steel (SUS) or the like, and is formed in a disc shape. An O-ring220, which is a seal member making contact with the lower end portion of the reaction tube203, is installed on an upper surface of the seal cap219. A rotation mechanism267configured to rotate a boat217, which will be described later, is installed under the seal cap219. A rotary shaft255of the rotation mechanism267, which penetrates the seal cap219, is connected to the boat217. The rotation mechanism267is configured to rotate the wafers200by rotating the boat217. The seal cap219is configured to be vertically moved up and down by a boat elevator115which is an elevator mechanism installed outside the reaction tube203. The boat elevator115is configured as a transfer device (transfer mechanism) which loads and unloads (transfers) the wafers200into and from the process chamber201by moving the seal cap219up and down.

The boat217serving as a substrate support is configured to support a plurality of wafers200, e.g., 25 to 200 wafers, in such a state that the wafers200are arranged in a horizontal posture and in multiple stages along a vertical direction with the centers of the wafers200aligned with one another. That is, the boat217is configured to arrange the wafers200in a spaced-apart relationship. The boat217is made of a heat resistant material such as, quartz or SiC. Heat insulating plates218made of a heat resistant material such as, quartz or SiC are installed below the boat217in multiple stages.

A temperature sensor263serving as a temperature detector is installed in the reaction tube203. Based on temperature information detected by the temperature sensor263, a state of supplying electric power to the heater207is adjusted such that the interior of the process chamber201has a desired temperature distribution. The temperature sensor263is installed along the inner wall of the reaction tube203.

As illustrated inFIG.3, the controller121, which is a control part (control means), may be configured as a computer including a central processing unit (CPU)121a, a random access memory (RAM)121b, a memory device121c, and an I/O port121d. The RAM121b, the memory device121cand the I/O port121dare configured to exchange data with the CPU121avia an internal bus121e. An input/output device122including, e.g., a touch panel or the like, is connected to the controller121.

The memory device121cincludes, 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 for specifying sequences and conditions of substrate processing as described hereinbelow, or the like is readably stored in the memory device121c. The process recipe functions as a program for causing the controller121to execute each sequence in the substrate processing, as described hereinbelow, to obtain a predetermined result. Hereinafter, the process recipe and the control program will be generally and simply referred to as a “program.” Furthermore, the process recipe will be simply referred to as a “recipe.” When the term “program” is used herein, it may indicate a case of including only the recipe, a case of including only the control program, or a case of including both the recipe and the control program. The RAM121bis configured as a memory area (work area) in which a program or data read by the CPU121ais temporarily stored.

The I/O port121dis connected to the MFCs241ato241d, the valves243ato243d, the pressure sensor245, the APC valve244, the vacuum pump246, the temperature sensor263, the heater207, the rotation mechanism267, the boat elevator115, and the like, as mentioned above.

The CPU121ais configured to read the control program from the memory device121cand execute the same. The CPU121ais also configured to read the recipe from the memory device121caccording to an input of an operation command from the input/output device122. In addition, the CPU121ais configured to control, according to the contents of the recipe thus read, the flow rate adjusting operation of various kinds of gases by the MFCs241ato241d, the opening/closing operation of the valves243ato243d, the opening/closing operation of the APC valve244, the pressure regulating operation performed by the APC valve244based on the pressure sensor245, the driving and stopping of the vacuum pump246, the temperature adjusting operation performed by the heater207based on the temperature sensor263, the operation of rotating the boat217with the rotation mechanism267and adjusting the rotation speed of the boat217, the operation of moving the boat217up and down with the boat elevator115, and the like.

The controller121may be configured by installing, on the computer, the aforementioned program stored in an external memory device123(for example, a magnetic disk such as an HDD, an optical disc such as a CD, a magneto-optical disc such as an MO, or a semiconductor memory such as a USB memory). The memory device121cor the external memory device123is configured as a non-transitory computer-readable recording medium. Hereinafter, the memory device121cand the external memory device123will 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 only the memory device121c, a case of including only the external memory device123, or a case of including both the memory device121cand the external memory device123. Furthermore, the program may be supplied to the computer using a communication means such as the Internet or a dedicated line, instead of using the external memory device123.

(2) Film Forming Process

A sequence example of forming a silicon oxycarbonitride film (SiOCN film) on a wafer200as a substrate using the aforementioned substrate processing apparatus, which is one of the processes for manufacturing a semiconductor device, will be described below with reference toFIG.4A. Here, an example in which a patterned wafer having a pattern (concavo-convex structure) formed on the surface of the patterned wafer is used as the wafer200will be described.FIG.5Ais an enlarged cross sectional view illustrating only a portion of a concavo-convex structure of a wafer200with a pattern having an upper surface200a, a side surface200b, and a lower surface (bottom surface)200cformed on the surface of the wafer200. The patterned wafer has a larger surface area than a bare wafer having no pattern formed on the surface of the bare wafer. In the following descriptions, the operations of the respective parts constituting the substrate processing apparatus are controlled by the controller121.

In the film forming sequence illustrated inFIG.4A, an SiOCN film is formed on a pattern by performing a cycle a predetermined number of times, the cycle non-simultaneously performing a step A of supplying the HCDS gas (precursor) to a wafer200having a pattern formed on the surface of the wafer200to form a first layer containing Si, a step B of supplying the TEA gas (first reactant) to the wafer200so that a substance obtained by decomposing a portion of the TEA gas is adsorbed on the first layer in order to form a second layer containing Si, C and N, and a step C of supplying an O2gas (second reactant) to the wafer200to oxidize the second layer in order to form a third layer containing Si, O, C and N.

Furthermore, at step B, the TEA gas is supplied until the density of an adsorption layer of a substance obtained by decomposing a portion of the TEA gas formed on each of at least the upper surface200a, the side surface200b, and the lower surface200cof the pattern is equalized (or substantially equalized).

In the present disclosure, for the sake of convenience, the sequence of the film forming process illustrated inFIG.4Amay sometimes be denoted as follows. The same denotation will be used in the modification examples and the like as described hereinbelow.
(HCDS→TEA→O2)×n→SiOCN

When the term “wafer” is used herein, it may refer to “a wafer itself” or “a laminated body of a wafer and a predetermined layer or film formed on the surface of the wafer.” In addition, when the phrase “a surface of a wafer” is used herein, it may refer to “a surface of a wafer itself” or “a surface of a predetermined layer or film formed on a wafer. Furthermore, in the present disclosure, the expression “a predetermined layer is formed on a wafer” may mean that “a predetermined layer is directly formed on a surface of a wafer itself” or that “a predetermined layer is formed on a layer formed on a wafer. In addition, when the term “substrate” is used herein, it may be synonymous with the term “wafer.”

(Wafer Charging and Boat Loading)

A plurality of wafers200is charged on the boat217(wafer charging). Thereafter, as illustrated inFIG.1, the boat217supporting the plurality of wafers200is lifted up by the boat elevator115and is loaded into the process chamber201(boat loading). In this state, the seal cap219seals the lower end of the reaction tube203via the O-ring220.

(Pressure Regulation and Temperature Adjustment)

The interior of the process chamber201, namely the space in which the wafers200are located, is vacuum-exhausted (depressurization-exhausted) by the vacuum pump246so as to reach a desired pressure (degree of vacuum). In this operation, the internal pressure of the process chamber201is measured by the pressure sensor245. The APC valve244is feedback-controlled based on the measured pressure information. The wafers200in the process chamber201are heated by the heater207to a desired temperature. In this operation, the state of supplying electric power to the heater207is feedback-controlled based on the temperature information detected by the temperature sensor263such that the interior of the process chamber201has a desired temperature distribution. In addition, the rotation of the wafers200by the rotation mechanism267begins. The exhaust of the interior of the process chamber201, and the heating and rotation of the wafers200may be continuously performed at least until the processing of the wafers200is completed.

Next, steps A to C are sequentially performed.

At this step, the HCDS gas is supplied to the wafer200within the process chamber201.

Specifically, the valve243ais opened to allow the HCDS gas to flow through the gas supply pipe232a. The flow rate of the HCDS gas is adjusted by the MFC241a. The HCDS gas is supplied into the process chamber201via the nozzle249aand is exhausted from the exhaust pipe231. At this time, the HCDS gas is supplied to the wafer200. At this time, the valves243cand243dare opened to allow an N2gas to flow through the gas supply pipes232cand232d.

Examples of the processing conditions at this step may be described as follows:HCDS gas supply flow rate: 1 to 2,000 sccm, specifically 10 to 1,000 sccmHCDS gas supply time (TA): 1 to 120 seconds, specifically 1 to 60 secondsN2gas supply flow rate: 0 to 10,000 sccmProcessing temperature: 250 to 800 degrees C., specifically 400 to 750 degrees C., more specifically 550 to 700 degrees C.Processing pressure: 1 to 2,666 Pa, specifically 67 to 1,333 Pa.

If the processing temperature is smaller than 250 degrees C., there may be a case where HCDS is difficult to be chemically adsorbed onto the wafer200and a practical film forming rate cannot be obtained. By setting the processing temperature to become 250 degrees C. or higher, it is possible to solve this. By setting the processing temperature to become 400 degrees C. or higher and further 550 degrees C. or higher, HCDS can be more sufficiently adsorbed onto the wafer200and a more sufficient film forming rate can be obtained.

If the processing temperature exceeds 800 degrees C., an excessive gas phase reaction may occur. Thus, the film thickness uniformity is likely to be deteriorates and the control of the film thickness uniformity is difficult. By setting the processing temperature at 800 degrees C. or lower, a moderate gas phase reaction can occur. Thus, it is possible to suppress the deterioration of the film thickness uniformity, and the control of the film thickness uniformity is possible. In particular, by setting the processing temperature at 750 degrees C. or lower and further 700 degrees C. or lower, the surface reaction becomes dominant over the gas phase reaction. Thus, it is easy to secure the film thickness uniformity and the control of the film thickness uniformity is facilitated.

By supplying the HCDS gas to the wafer200under the aforementioned conditions, an Si-containing layer containing Cl having a thickness of, for example, about less than one atomic layer (one molecular layer) to several atomic layers (several molecular layers) is formed as a first layer (initial layer) on the surface of the wafer200, namely on each of the surface200a, the side surface200b, and the lower surface200cof the pattern formed on the surface of the wafer200. The first layer is formed on the surface of the wafer200by the physical adsorption of HCDS, the chemisorption of a substance obtained by decomposing a portion of HCDS, the thermal decomposition of HCDS, or the like. In the present disclosure the substance constituting the Si-containing layer containing Cl is also referred to as SixCly(where 1≤x≤2 and 0≤y≤6) for the sake of convenience. Furthermore, the Si-containing layer containing Cl is also referred to simply as an Si-containing layer for the sake of convenience.

The HCDS gas containing Cl is a gas which is active (easily decomposed) compared with the TEA gas composed of only N, C and H and which has a high adsorption efficiency onto the surface of the wafer200. Therefore, by setting the supply time TAof the HCDS gas at a time which falls within the aforementioned range, namely without setting the HCDS gas supply time TAat a time as the same as TBdescribed hereinbelow, it is possible to equalize the density of the first layer formed on each of the surface200a, the side surface200b, and the lower surface200cof the pattern.FIG.5Bis a schematic diagram illustrating a state in which the first layer is continuously formed at a high density (equivalent density) on each of the surface200a, the side surface200b, and the lower surface200cof the pattern by performing step A. InFIG.5B, the symbol ∘ indicates SixCly. This is the same inFIGS.5C and5D.

After the first layer is formed, the valve243ais closed to stop the supply of the HCDS gas to the wafer200. Then, the interior of the process chamber201is vacuum-exhausted and the gas or the like, which remains within the process chamber201, is removed from the interior of the process chamber201. At this time, the valves243cand243dare opened to supply N2gas into the process chamber201. The N2gas acts as a purge gas. Thus, the interior of the process chamber201is purged.

As the precursor, it may be possible to use, in addition to the HCDS gas, for example, a chlorosilane-based gas such as monochlorosilane (SiH3Cl, abbreviation: MCS) gas, dichlorosilane (SiH2Cl2, abbreviation: DCS) gas, trichlorosilane (SiHCl3, abbreviation: TCS) gas, tetrachlorosilane (SiCl4, abbreviation: STC) gas, octachlorotrisilane (Si3Cl8, abbreviation: OCTS) gas or the like. As the precursor gas, it may be possible to use tetrafluorosilane (SiF4) gas, tetrabromosilane (SiBr4) gas, tetraiodosilane (SiI4) gas or the like. That is, as the precursor gas, it may be possible to use a halosilane-based gas other than a chlorosilane-based gas such as a fluorosilane-based gas, a bromosilane-based gas, an iodosilane-based gas or the like.

Furthermore, as the precursor, it may be possible to use an alkylenhalosilane-based gas such as 1,2-bis (trichlorosilyl) ethane ((SiCl3)2C2H4, abbreviation: BTCSE) gas, bis (trichlorosilyl) methane ((SiCl3)2CH2, abbreviation: BTCSM) gas or the like, or an alkylhalosilane-based gas such as 1,1,2,2-tetrachloro-1,2-dimethyldisilane (CH3)2Si2Cl4, abbreviation: TCDMDS) gas, 1,2-dichloro-1,1,2,2-tetramethyldisilane ((CH3)4Si2Cl2, abbreviation: DCTMDS) gas, 1-monochloro-1,1,2,2,2-pentamethyldisilane ((CH3)5Si2Cl, abbreviation MCPMDS) gas or the like. Since all of these gases contain Si—C bonds, it is possible to increase the C concentration in the SiOCN film finally formed.

In addition, as the precursor, it may be possible to use a silicon hydride gas such as monosilane (SiH4, abbreviation: MS) gas, disilane (Si2H6, abbreviation: DS) gas, trisilane (Si3H8abbreviation: TS) gas or the like.

Furthermore, as the precursor, it may be possible to suitably use an aminosilane-based gas such as tetrakis-dimethylaminosilane (Si[N(CH3)2]4, abbreviation: 4DMAS) gas, tris-dimethylaminosilane (Si[N(CH3)2]3H, abbreviation: 3DMAS) gas, bis-diethylaminosilane (Si[N(C2H5)2]2H2, abbreviation: BDEAS) gas, bis-tert-butylaminosilane (SiH2[NH(C4H9)]2, abbreviation: BTBAS) gas, diisopropylaminosilane (SiH3N[CH(CH3)2]2, abbreviation: DIPAS) gas or the like. Since all of these gases contain Si—N bonds, it is possible to increase the N concentration in the SiOCN film finally formed.

As the inert gas, it may possible to use, in addition to the N2gas, for example, a rare gas such as Ar gas, He gas, Ne gas, Xe gas or the like. This is the same at steps B and C.

After step A is completed, the TEA gas is supplied to the wafer200within the process chamber201, i.e., the first layer formed on the wafer200.

At this step, the opening/closing control of the valves243bto243dis performed in the same procedure as the opening/closing control of the valves243a,243cand243dat step A. The flow rate of the TEA gas is adjusted by the MFC241b. The TEA gas is supplied into the process chamber201via the nozzle249band is exhausted from the exhaust pipe231. At this time, the TEA gas is supplied to the wafer200.

Examples of the processing conditions at this step may be described as follows:TEA gas supply flow rate: 1 to 2,000 sccm, specifically 10 to 1,000 sccmTEA gas supply time TB: time longer than TAdescribed above, specifically two times or more TA, more specifically four times or more TA, even more specifically 10 times or more TA, much more specifically 15 times or more TAProcessing pressure: 1 to 4,000 Pa, specifically 1 to 3,000 Pa.
Other processing conditions may be similar to the processing conditions at step A.

By supplying the TEA gas to the wafer200under the aforementioned conditions, the first layer formed on the wafer200at step A may react with the TEA gas. That is, Cl contained in the first layer may react with an ethyl group contained in the TEA gas. Thus, at least some of Cl contained in the first layer can be drawn out (separated) from the first layer and at least some of a plurality of ethyl groups contained in the TEA gas can be separated from the TEA gas. Furthermore, it becomes possible to combine N of the TEA gas, from which at least some of the ethyl groups have been separated, and Si contained in the first layer to form Si—N bonds. At this time, it also becomes possible to combine C contained in the ethyl groups (—CH2CH3) separated from the TEA gas and Si contained in the first layer to form Si—C bonds. As a result, Cl is desorbed from the first layer, and an adsorption layer of a substance obtained by decomposing a portion of TEA is formed on the first layer. In the present disclosure, the substance obtained by decomposing a portion of TEA is also referred to as N(CxHy)z(where 0≤x≤2, 0≤y≤5, and 0≤z≤3) for the sake of convenience. A layer including the first layer and the adsorption layer of N(CxHy)zformed on the first layer, i.e., a silicon carbonitride layer (SiCN layer) which is a layer containing Si, C and N is formed as a second layer on the wafer200.

Compared with the HCDS gas containing Cl, the TEA gas is a gas which has a low degree of activity (difficult to be decomposed) and which has a low adsorption efficiency onto the surface of the wafer200. Therefore, if the supply time TBof the TEA gas is set to be shorter than or equal to the supply time TAof the HCDS gas (TB≤TA), the density of the adsorption layer of N(CxHy)zformed on each of the surface200a, the side surface200band the lower surface200cof the pattern may differ.FIG.5Cis a schematic diagram illustrating a density of the adsorption layer of N(CxHy)zformed on the surface of the wafer200(on the surface of the first layer) when set to be TB≤TA. InFIG.5C, the symbol Θ indicates N(CxHy)z. This is the same inFIG.5D.

As illustrated inFIG.5C, when set to be TB≤TA, the adsorption layer of N(CxHy)zmay be formed at a somewhat high density on the surface200aof the pattern. However, the adsorption amount of N(CxHy)zsignificantly decreases on the side surface200bof the pattern and the adsorption layer of N(CxHy), may be a discontinuous layer. Furthermore, N(CxHy)zhardly adsorbs onto the lower surface200cof the pattern and no adsorption layer of N(CxHy), may be formed. When the density of the adsorption layer of N(CxHy)zbecomes unequal as illustrated inFIG.5C, the thickness of the SiOCN film finally formed may significantly differ on each of the surface200a, the side surface200b, and the lower surface200cof the pattern. As a result, a phenomenon that the film thickness (average film thickness) of the SiOCN film formed on the wafer200is smaller than the film thickness (average film thickness) of the SiOCN film formed on the bare wafer by the same processing procedures and processing conditions as in this case, i.e., a film thickness drop phenomenon, is likely to occur. Furthermore, when the density of the adsorption layer of N(CxHy), becomes unequal as illustrated inFIG.5C, at least one of the N concentration and the C concentration in the adsorption layer of N(CxHy)zformed on each of the surface200a, the side surface200band the lower surface200cof the pattern may differ. As a result, the composition of the SiOCN film finally formed may significantly differ on each of the surface200a, the side surface200band the lower surface200cof the pattern.

On the other hand, as in this embodiment, by setting the supply time TBof the TEA gas to become longer than the supply time TAof the HCDS gas (TB>TA), it is possible to equalize the density of the adsorption layer of N(CxHy)zformed on each of the surface200a, the side surface200b, and the lower surface200cof the pattern.FIG.5Dis a schematic diagram illustrating a state in which the adsorption layer of N(CxHy)zis continuously formed at a high density (equivalent density) on each of the surface200a, the side surface200band the lower surface200cof the pattern by setting TB>TA. By arranging the density distribution of the adsorption layer of N(CxHy)zin the plane as inFIG.5D, it is possible to equalize the thickness of the SiOCN film finally formed on each of the surface200a, the side surface200band the lower surface200cof the pattern. As a result, according to this embodiment, even when a patterned wafer is used as the wafer200, it is possible to avoid a decrease of the film thickness (average film thickness) of the SiOCN film, i.e., to suppress the occurrence of the film thickness drop phenomenon. In addition, by arranging the density distribution of the adsorption layer of N(CxHy)zin the plane as inFIG.5D, it is possible to equalize at least one of the N concentration and the C concentration in the adsorption layer of N(CxHy)zformed on each of the surface200a, the side surface200band the lower surface200cof the pattern. As a result, it is also possible to equalize the composition of the SiOCN film finally formed on each of the surface200a, the side surface200band the lower surface200cof the pattern. Furthermore, the aforementioned effects may be sufficiently achieved by setting TBat a time greater than or equal to twice TA(TB≥2TA), and the aforementioned effects may be more sufficiently achieved by setting TBat a time greater than or equal to four times TA(TB≥4TA). In addition, the aforementioned effects may be reliably achieved by setting TBat a time of more than 10 times TA(TB≥10TA), and the aforementioned effects may be more reliably achieved by setting TBat a time greater than or equal to 15 times TA(TB≥15TA). For example, when TAis set at a time which falls within a range of 10 to 13 seconds, the aforementioned effects may be reliably achieved by setting TBat 100 to 130 seconds, and the aforementioned effects may be more reliably achieved by setting TBat 150 to 195 seconds. However, it is desirable to set TBat a time less than or equal to 20 times TA(TB≤20TA) in consideration of productivity.

Furthermore, in order to achieve the aforementioned effects, it is effective not only to lengthen the supply time TBof the TEA gas but also to increase the supply flow rate of the TEA gas. However, the TEA gas is a gas obtained by vaporizing a liquid precursor staying in a liquid state under a room temperature and an atmospheric pressure, and in many cases, it is difficult to make the flow rate thereof large. Therefore, when the gas obtained by vaporizing the liquid precursor such as the TEA gas is used as the first reactant, a method of adjusting the supply time TBof the TEA gas, i.e., a method of setting TB>TA, specifically TB≥2TA, more specifically TB≥4TA, more specifically TB≥10TA, even more specifically TB≥15TA, as in this embodiment, is particularly effective.

After the second layer is formed, the valve243bis closed to stop the supply of the TEA gas to the wafer200. Then, the gas or the like, which remains within the process chamber201, is removed from the interior of the process chamber201by the same processing procedure as that of step A.

In addition, as the first reactant, it may be possible to use, in addition to the amine-based gas, an organic hydrazine gas. As the organic hydrazine gas, it may be possible to use a methylhydrazine-based gas such as monomethylhydrazine ((CH3)HN2H2, abbreviation: MMH) gas, dimethylhydrazine ((CH3)2N2H2, abbreviation: DMH) gas, trimethylhydrazine ((CH3)2N2(CH3)H, abbreviation: TMH) gas or the like, or an ethylhydrazine-based gas such as ethylhydrazine ((C2H5)HN2H2, abbreviation: EH) gas.

After step B is completed, an O2gas is supplied to the wafer200within the process chamber201, i.e., the second layer formed on the wafer200.

At this step, the opening/closing control of the valves243bto243dis performed in the same procedure as the opening/closing control of the valves243a,243cand243dat step A. The flow rate of the O2gas is adjusted by the MFC241b. The O2gas is supplied to the process chamber201via the nozzle249band is exhausted from the exhaust pipe231. At this time, the O2gas is supplied to the wafer200.

Examples of the processing conditions at this step may be described as follows:O2gas supply flow rate: 100 to 10,000 sccmO2gas supply time TC: 1 to 120 seconds, specifically 1 to 60 secondsProcessing pressure: 1 to 4,000 Pa, specifically 1 to 3,000 Pa.
Other processing conditions may be similar to the processing conditions of step A.

By supplying the O2gas to the wafer200under the aforementioned conditions, it is possible to modify (oxidize) at least a portion of the second layer formed on the wafer200by performing step B. That is, at least a portion of the O component contained in the O2gas can be added to the second layer to form Si—O bonds in the second layer. By modifying the second layer, a silicon oxycarbonitride layer (SiOCN layer) which is a layer containing Si, O, C and N is formed as a third layer on the wafer200. When forming the third layer, at least a portion of the C component and the N component contained in the second layer is maintained in the second layer without being desorbed from the second layer. When forming the third layer, Cl contained in the second layer constitutes a gaseous substance containing at least Cl in the process of modification reaction with the O2gas and is discharged from the interior of the process chamber201. That is, an impurity such as Cl in the second layer is pulled out or desorbed from the interior of the second layer so as to be separated from the second layer. Thus, the third layer becomes a layer having less impurity such as Cl than the second layer.

After the third layer is formed, the valve243bis closed to stop the supply of the O2gas to the wafer200. Then, the gas or the like, which remains within the process chamber201, is removed from the interior of the process chamber201by the same processing procedure as that of step A.

As the oxidizing gas as the second reactant, it may be possible to use, in addition to the O2gas, an O-containing gas such as water vapor (H2O gas), nitrogen monoxide (NO) gas, nitrous oxide (N2O) gas, nitrogen dioxide (NO2) gas, carbon monoxide (CO) gas, carbon dioxide (CO2) gas, ozone (O3) gas, hydrogen (H2) gas+O2gas, H2gas+O3gas or the like.

[Performing a Predetermined Number of Times]

A cycle which includes non-simultaneously, i.e., non-synchronously, performing steps A to C is implemented once or more (n times). Thus, an SiOCN film having a desired composition and a desired film thickness can be formed on the wafer200. The aforementioned cycle may be repeated multiple times. That is, the thickness of the third layer formed per one cycle may be set to be smaller than a desired film thickness and the aforementioned cycle may be repeated multiple times until the thickness of the SiOCN film formed by laminating the third layer becomes equal to the desired film thickness.

(After Purge Step and Atmospheric Pressure Return)

After the SiOCN film having a desired composition and a desired film thickness is formed on the wafer200, the N2gas is supplied from each of the nozzles249aand249binto the process chamber201and is exhausted from the exhaust pipe231. Thus, the interior of the process chamber201is purged and the gas or the reaction byproduct, which remains within the process chamber201, is removed from the interior of the process chamber201(after purge). Thereafter, the internal atmosphere of the process chamber201is substituted by an inert gas (inert gas substitution). The internal pressure of the process chamber201is returned to an atmospheric pressure (atmospheric pressure return).

The seal cap219is moved down by the boat elevator115to open the lower end of the reaction tube203. The processed wafers200supported on the boat217are unloaded from the lower end of the reaction tube203to the outside of the reaction tube203(boat unloading). The processed wafers200are unloaded to the outside of the reaction tube203and are subsequently discharged from the boat217(wafer discharging).

(3) Effects According to the Present Embodiment

According to the present embodiment, one or more effects as set forth below may be achieved.(a) By setting TB>TAat step B, it becomes possible to equalize the density of the adsorption layer of N(CxHy)zformed on each of the surface200a, the side surface200b, and the lower surface200cof the pattern. This makes it possible to equalize the thickness of the SiOCN film finally formed on each of the surface200a, the side surface200b, and the lower surface200cof the pattern. As a result, it becomes possible to suppress the occurrence of the film thickness drop phenomenon.(b) By setting TB>TAat step B, it becomes possible to equalize at least one of the N concentration and the C concentration in the adsorption layer of N(CxHy)zformed on each of the surface200a, the side surface200b, and the lower surface200cof the pattern. This makes it possible to equalize the composition of the SiOCN film finally formed on each of the surface200a, the side surface200band the lower surface200cof the pattern.(c) By setting TB>TAor TB>TCat step B, it becomes possible to increase the thickness of the SiOCN layer formed per one cycle, i.e., to increase the cycle rate.(d) By setting TB>TAor TB>TCat step B, it becomes possible to finely adjust the composition in the SiOCN film finally formed. Specifically, it becomes possible to control the composition of the SiOCN film in a direction to increase the C concentration in the SiOCN film and in a direction to reduce the N concentration in the SiOCN film, respectively, as TBis lengthened.(e) Since only TB, not TA, is lengthened, it becomes possible to suppress the occurrence of the film thickness drop phenomenon while avoiding the deterioration of the wafer in-plane film thickness uniformity and the step coverage of the SiOCN film finally formed. On the other hand, if not only TBbut also TAis set to be as long as TB, even though the occurrence of the film thickness drop phenomenon could be suppressed, the decomposition of HCDS on the wafer200becomes excessive. The wafer in-plane film thickness uniformity and the step coverage of the SiOCN film finally formed are likely to be deteriorated, respectively.(f) The effects mentioned above can be similarly achieved in the case where the aforementioned precursor other than the HCDS gas is used, in the case where the aforementioned first reactant other than the TEA gas is used, in the case where the aforementioned second reactant other than the O2gas is used, or in the case where the aforementioned inert gas other than the N2gas is used.

(4) Modification Examples

The present embodiment may be modified as in the modification examples described below. These modification examples may be arbitrarily combined.

Modification Example 1

In the film forming sequence described above, the method of setting TB>TAhas been mainly described. However, even in the case of setting TB>TC, the same effects as those of the film forming sequence illustrated inFIG.4Amay be achieved. Furthermore, the aforementioned effects may be sufficiently achieved by setting TBat a time greater than or equal to 1.5 times TC(TB≥1.5TC), and the aforementioned effects may be more sufficiently achieved by setting TBat a time greater than or equal to 3 times TC(TB≥3TC). In addition, the aforementioned effects may be reliably achieved by setting TBat a time greater than or equal to five times TC(TB≥5TC), and the aforementioned effects may be more reliably achieved by setting TBat a time greater than or equal to 10 times TC(TB≥10TC). However, it is desirable to set TBat a time less than or equal to 20 times TC(TB≤20TC) in consideration of productivity. Other processing procedures and processing conditions may be similar to the processing sequences and processing conditions of the film forming sequence described above.

Modification Example 2

As in the film forming sequence illustrated inFIG.4Bor set forth below, the TEA gas may be dividedly (in pulses or intermittently) supplied at step B per cycle. That is, at step B per cycle, the supply of the TEA gas to the wafer200and the purge operation of the interior of the process chamber201may be alternately repeated a plurality of times (m times).
(HCDS→TEA×m→O2)×n⇒SiOCN

Even in this modification example, at step B, the TEA gas may be continuously and dividedly supplied until the density of the adsorption layers of N(CxHy)zformed on each of at least the upper surface200a, the side surface200b, and the lower surface200cof the pattern is equalized. For example, it becomes possible to realize this by setting the total supply time (the total supply time of each pulse) of the TEA gas at step B per cycle to become longer than the supply time TAof the HCDS gas at step A per cycle or to become longer than the supply time TCof the O2gas at step C per cycle.

Furthermore, in this modification example, it is desirable to dividedly supply the TEA gas in multiple times by setting the supply time of the TEA gas per pulse at step B in one cycle shorter than the supply time TAof the HCDS gas at step A per cycle. It is also desirable to dividedly supply the TEA gas in multiple times by setting the supply time of the TEA gas per pulse at step B in one cycle shorter than the supply time of the O2gas at step C per cycle. Other processing procedures and processing conditions may be similar to the processing procedures and processing conditions of the film forming sequence illustrated inFIG.4A.

Even in this modification example, the same effects as those of the film forming sequence illustrated inFIG.4Amay be achieved.

Furthermore, according to this modification example, the adsorption efficiency onto the surface of the wafer200of N(CxHy)zcan be increased by dividedly supplying the TEA gas at step B. This is because a portion of the TEA gases supplied to the wafer200stays on the surface of the first layer without causing a reaction with the first layer and thus hampers the formation of the adsorption layer of N(CxHy)zonto the first layer. This is also because the reaction byproduct generated in forming the adsorption layer of N(CxHy)zstays on the surface of the first layer and thus hampers the formation of the adsorption layer of N(CxHy)zonto the first layer. On the other hand, as in this modification example, by alternately supplying the TEA gas to the wafer200and the purge operation of the interior of the process chamber201a plurality of times at step B, it becomes possible to quickly remove the factor of hampering the formation of the adsorption layer of N(CxHy)zonto the first layer (the TEA gas or the reaction byproduct which failed in the adsorption reaction) from the surface of the first layer. As a result, it becomes possible to increase the adsorption efficiency of N(CxHy)zonto the surface of the wafer200, and to further suppress the occurrence of the film thickness drop phenomenon in the SiOCN film finally formed. It also becomes possible to further increase the thickness of the SiOCN layer formed per cycle, i.e., to further increase the cycle rate.

Modification Example 3

The silicon carbonitride film (SiCN film) containing Si, C, and N may be formed on the wafer200without performing step C as in the film forming sequences denoted below. The processing procedures and processing conditions of steps A and B in this modification example may be similar to those of steps A and B of the film forming sequence illustrated inFIG.4A.
(HCDS→TEA)×n⇒SiCN
(HCDS→TEA××m)×n⇒SiCN

Even in this modification example, the same effects as those of the film forming sequence illustrated inFIG.4Amay be achieved.

OTHER EMBODIMENTS

While the embodiment of the present disclosure has been specifically described above, the present disclosure is not limited to the aforementioned embodiment but may be differently modified without departing from the spirit of the present disclosure.

For example, the present disclosure may be suitably applied to a case where a metal thin film such as titanium oxycarbonitride film (TiOCN film) or titanium carbonitride film (TiCN film) is formed. These films may be formed by the film forming sequences denoted below using, for example, a precursor such as titanium tetrachloride (TiCl4) gas or the like, or a reactant such as the amine-based gas described above, an oxidizing gas or the like. Even in the case of performing these film forming sequences, a film may be formed under the same processing procedures and processing conditions as those of the aforementioned embodiment, and the same effects as those of the aforementioned embodiment may be achieved.
(TiCl4→TEA→O2)×n⇒TiOCN
(TiCl4→TEA×m→O2)×n⇒TiOCN
(TiCl4→TEA)×n⇒TiCN
(TiCl4→TEA×m)×n⇒TiCN

Recipes used in substrate processing may be prepared individually according to the processing contents and may be stored in the memory device121cvia a telecommunication line or the external memory device123. Moreover, at the start of substrate processing, the CPU121amay properly select an appropriate recipe from the recipes stored in the memory device121caccording to the contents of the substrate processing. Thus, it is possible for a single substrate processing apparatus to form films of different kinds, composition ratios, qualities and thicknesses with the enhanced reproducibility. In addition, it is possible to reduce an operator's burden and to quickly start the substrate processing while avoiding an operation error.

The recipes mentioned above are not limited to newly-prepared ones but may be prepared by, for example, modifying the existing recipes already installed in the substrate processing apparatus. When modifying the recipes, the modified recipes may be installed in the substrate processing apparatus via a telecommunication line or a recording medium storing the recipes. In addition, the existing recipes already installed in the substrate processing apparatus may be directly modified by operating the input/output device122of the existing substrate processing apparatus.

In the aforementioned embodiment, there has been described an example in which films are formed using a batch-type substrate processing apparatus capable of processing a plurality of substrates at a time. The present disclosure is not limited to the aforementioned embodiment but may be appropriately applied to, e.g., a case where films are formed using a single-wafer-type substrate processing apparatus capable of processing a single substrate or several substrates at a time. In addition, in the aforementioned embodiment, there has been described an example in which films are formed using a substrate processing apparatus provided with a hot-wall-type processing furnace. The present disclosure is not limited to the aforementioned embodiment but may be appropriately applied to a case where films are formed using a substrate processing apparatus provided with a cold-wall-type processing furnace.

In the case of using these substrate processing apparatuses, a film forming process may be performed by the sequence and processing conditions similar to those of the embodiment and modification examples described above. Effects similar to those of the embodiment and modification examples described above may be achieved.

The embodiment and modification examples described above may be appropriately combined with one another. In addition, the processing procedures and processing conditions used at this time may be similar to, for example, the processing procedures and processing conditions of the film forming sequence of the embodiment described above.

Various films formed by the embodiment and modification examples described above may be widely used as an insulating film, a spacer film, a mask film, a charge storage film, a stress control film, and the like. It has been required that the more accurate film thickness control be realized for films formed on a wafer according to the recent miniaturization of semiconductor devices. The present disclosure capable of accurately controlling the thickness of a film formed on a patterned wafer having a high density pattern formed on the surface of the patterned wafer is extremely useful as a technique for responding to such requirement.

EMBODIMENT EXAMPLES

Next, embodiment examples will be described.

In embodiment example 1, a process of forming an SiOCN film on a plurality of wafers was performed twice using the substrate processing apparatus illustrated inFIG.1by the film forming sequence illustrated inFIG.4A. In the first film forming process, all of 100 wafers charged on the boat were defined as bare wafers. In the second film forming process, 25 wafers on the upper side among the wafers charged on the boat were defined as patterned wafers having a surface area 10 times larger than that of the bare wafers, and the other 75 wafers were defined as the bare wafers. In either of the film forming processes, the supply time TBof the TEA gas at step B per cycle was set to be about 2 to 4 times the supply time TAof the HCDS gas at step A per cycle and was set to be about 1 to 5 times the supply time TCof the O2gas per cycle. Other processing conditions were set at predetermined conditions which fall within the range of the processing conditions described in the aforementioned embodiment.

In embodiment example 2, a process of forming an SiOCN film on a plurality of wafers was performed twice using the substrate processing apparatus illustrated inFIG.1by the film forming sequence illustrated inFIG.4A. In the first film forming process, all of 100 wafers charged on the boat were defined as bare wafers. In the second film forming process, 25 wafers on the upper side among the wafers charged on the boat were defined as patterned wafers having a surface area 10 times larger than that of the bare wafers, and the other 75 wafers were defined as the bare wafers. In either of the film forming processes, the supply time TBof the TEA gas at step B per cycle was set to be about 10 to 15 times the supply time TAof the HCDS gas at step A per cycle and was set to be about 10 to 20 times the supply time TCof the O2gas per cycle. Other processing conditions were set to be equal to the processing conditions of embodiment example 1.

In embodiment example 3, a process of forming an SiOCN film on a plurality of wafers was performed twice using the substrate processing apparatus illustrated inFIG.1by the film forming sequence illustrated inFIG.4B. In the first film forming process, all of 100 wafers charged on the boat were defined as bare wafers. In the second film forming process, 25 wafers on the upper side among the wafers charged on the boat were defined as patterned wafers having a surface area 10 times larger than that of the bare wafers, and the other 75 wafers were defined as the bare wafers. In either of the film forming processes, the total supply time (the total supply time of each pulse) of the TEA gas at step B per cycle was set to be equal to the supply time TBof the TEA gas at step B per cycle in embodiment example 1. Other processing conditions were set to be equal to the processing conditions of embodiment example 1.

In a comparative example, a process of forming an SiOCN film on a plurality of wafers, was performed twice using a substrate processing apparatus illustrated inFIG.1by a film forming sequence in which a cycle of non-simultaneously performing supplying an HCDS gas to a wafer, supplying a TEA gas to the wafer, and supplying an O2gas to the wafer is implemented a plurality of times. In the first film forming process, all of 100 wafers charged on the boat were defined as bare wafers. In the second film forming process, 25 wafers on the upper side among the wafers charged on in the boat were defined as patterned wafers having a surface area 10 times larger than that of the bare wafers, and the other 75 wafers were defined as the bare wafers. In either of the film forming processes, the supply time of TEA gas per cycle was set to be equal to the supply time of HCDS gas per cycle. Other processing conditions were set to be equal to the processing conditions of embodiment example 1.

Furthermore, in each of embodiment examples 1 to 3 and the comparative example, each of the average in-plane film thickness (AV1) of the SiOCN film formed on the bare wafers in the first film forming process and the average in-plane film thickness (AV2) of the SiOCN film formed on the patterned wafers in the second film forming process was measured, and the degree of occurrence of the film thickness drop phenomenon was evaluated.FIGS.6A to6Care diagrams illustrating results of measuring the thicknesses of the SiOCN film in the comparative example, embodiment example 1, and embodiment example 3, respectively. The horizontal axis in each drawing shows an average in-plane film thickness (Å), and the vertical axis shows a position of the wafer charged on the boat (where 120 is at the TOP side and 0 is at the BOTTOM side). In the drawing, the symbol ♦ represents an average in-plane film thickness (AV1) of the SiOCN film formed on the bare wafer in the first film forming process, and the symbol ⋄ represents an average in-plane film thickness (AV2) of the SiOCN film formed on the patterned wafer in the second film forming process.

As illustrated inFIG.6A, in the comparative example, it was found that there occurs the film thickness drop phenomenon that the average in-plane film thickness (AV2) of the SiOCN film formed on the patterned wafer was smaller than the average in-plane film thickness (AV1) of the SiOCN film formed on the bare wafer, and the film thickness drop rate represented by [(AV1−AV2)/AV1]×100 reaches 14.9%.

Furthermore, as illustrated inFIG.6B, it was found that the film thickness drop rate in embodiment example 1 was smaller than that in the comparative example which is about 9.2%. That is, it was found that the occurrence of the film thickness drop phenomenon can be suppressed by setting the supply time TBof the TEA gas at step B per cycle larger than the supply time TAof the HCDS gas at step A per cycle and larger than the supply time TCof the O2gas at step C per cycle.

Although not illustrated, it was recognized that the film thickness drop rate in embodiment example 2 was smaller than those in the comparative example and embodiment example 1 which is about 6.0%. That is, it was recognized that the occurrence of the film thickness drop phenomenon can be drastically suppressed by setting the supply time TBof the TEA gas at step B per cycle to about 10 to 15 times the supply time TAof the HCDS gas at step A per cycle and to about 10 to 20 times the supply time TCof the O2gas at step C per cycle.

Furthermore, as illustrated inFIG.6C, it was found that the film thickness drop rate in embodiment example 3 was smaller than those in the comparative example and embodiment example 1 which is about 6.0%. That is, it was found that the occurrence of the film thickness drop phenomenon can be drastically suppressed by dividedly supplying the TEA gas and by setting the total supply time of the TEA gas at step B per cycle to become larger than the supply time TAof the HCDS gas at step A per cycle.

According to the present disclosure in some embodiments, it is possible to suppress the occurrence of a film thickness drop phenomenon when a film is formed on a substrate.