Boron nitride film formation method and formation device

Abstract

Disclosed is a boron nitride film formation method including (a) a step for executing a sequence. The sequence includes: (a1) a step for supplying a first processing gas containing a first borazine compound and plasma chemical species to a substrate disposed in a chamber of a film formation device, in order to form a boron nitride film on the substrate; and (a2) a step for supplying plasma chemical species to the substrate without supplying the first processing gas to the substrate. The film formation method further includes (b) a step for supplying a second processing gas that contains a second borazine compound containing an alkyl group to the substrate without supplying plasma chemical species to the substrate. The film formation method further includes a step for repeating a cycle including (a) and (b).

Description

Boron nitride film forming method and film forming apparatus

[0001] An exemplary embodiment of the present disclosure relates to a method and apparatus for forming a boron nitride film.

[0002] Patent Document 1 describes a method of generating plasma of a boron-containing gas and a nitrogen-containing gas in a plasma generation region and forming a hexagonal boron nitride film (BN film) on the surface of a substrate by plasma CVD (Chemical Vapor Deposition).

[0003] Japanese Patent Application Laid-Open No. 2020-147826

[0004] The present disclosure provides a deposition technique that improves the step coverage of boron nitride films.

[0005] In one exemplary embodiment, a method for depositing a boron nitride film is provided. The method includes (a) performing a sequence. The sequence includes: (a1) supplying a first process gas containing a first borazine compound and plasma species to a substrate disposed in a chamber of a deposition apparatus to form a boron nitride film on the substrate; and (a2) supplying plasma species to the substrate without supplying the first process gas to the substrate. The method further includes (b) supplying a second process gas containing a second borazine compound containing an alkyl group to the substrate without supplying plasma species to the substrate. The method further includes repeating a cycle including (a) and (b).

[0006] According to one exemplary embodiment, a deposition technique can be provided that improves the step coverage of boron nitride films.

[0007] 1 is a timing chart showing a method for forming a boron nitride film (BN film) according to an exemplary embodiment; FIG. 2 is a timing chart showing a method for forming a BN film according to another exemplary embodiment; FIG. 3 is a timing chart showing a method for forming a BN film according to yet another exemplary embodiment; FIG. 4 is a diagram showing whether a hexagonal structure BN film (h-BN) or an amorphous structure BN film (a-BN) is formed at the pressure in the chamber and the processing temperature of the substrate when the supply time (depo time) of the first processing gas and plasma in the first process is 2 seconds; FIG. 5 is a diagram showing whether an h-BN film or an a-BN film is formed at the pressure in the chamber and the processing temperature of the substrate when the depo time is 4 seconds; FIG. 6 is a diagram showing the configuration of a BN film forming apparatus according to an exemplary embodiment; FIG. 7 is a schematic diagram of a cross-sectional TEM image of a sample substrate after the formation of a BN film; FIG. 8 is a diagram showing the results of an experiment measuring the growth suppression effect of the BN film. 1 is a diagram showing the results of an experiment measuring the relationship between the number x of sequences SQ1 in one cycle of cycle CY and the amount of BN film formed per sequence (GPC). FIG. 2 is a diagram showing the results of an experiment measuring the relationship between the time (Flow time) of process ST3 and GPC. FIG. 3 is a diagram showing the results of an experiment measuring the relationship between the flow rate of TMB in process ST3 and GPC. FIG. 4 is a diagram showing the results of an experiment measuring the relationship between pressure in process ST3 and GPC. FIG. 5 is a diagram showing the results of an experiment measuring the relationship between pressure in process ST3 and GPC.

[0008] Various exemplary embodiments will be described in detail below with reference to the drawings, in which the same or equivalent parts are designated by the same reference numerals.

[0009] <Boron Nitride Film Formation Method> Figure 1 is a timing chart showing a method for forming a boron nitride film (BN film) according to one example embodiment. In Figure 1, the states in which various gases are supplied and the states in which radio frequency (RF) power is supplied in the film formation method of one embodiment (hereinafter referred to as "method MT1") are indicated by solid or dotted lines with arrows.

[0010] As shown in FIG. 1 , in the method MT1, a cycle CY is repeated. In the method MT1, the cycle CY is performed y times, where y is an integer equal to or greater than 2. The cycle CY is repeated with a substrate accommodated in a chamber of a film forming apparatus. The substrate may be, for example, a semiconductor substrate. The semiconductor substrate may include a semiconductor region containing a semiconductor material such as Si, and may have desired films and structures formed on the semiconductor region.

[0011] The cycle CY includes a sequence SQ1 and a step ST3. In the cycle CY, the sequence SQ1 is performed x times, and then the step ST3 is performed, where x is an integer equal to or greater than 1. In the cycle CY, the step ST3 may be part of a sequence SQ2. The sequence SQ2 may include a step STc that is performed after the step ST3.

[0012] The sequence SQ1 includes a step ST1 and a step ST2. The sequence SQ1 of the method MT1 may further include a step STa and a step STb, or may include the step STb without including the step STa. The step STa is performed before the step ST1. In the step STa, the chamber is purged. In the step STa, a purge gas may be supplied into the chamber. The purge gas may be an inert gas. The inert gas may be, for example, a rare gas such as He gas.

[0013] In step STa, a flow of a first process gas may be prepared, as indicated by a dashed line with an arrow in FIG. 1 . The first process gas is used in the subsequent step ST1. To prepare the flow of the first process gas, in step STa, the first process gas may be flowed into an exhaust line such as the exhaust line of the film forming apparatus 100 described below. Alternatively, in step STa, the first process gas may be filled into a tank such as a fill tank of the film forming apparatus 100.

[0014] In step STa, a plasma source gas may be supplied into the chamber. The plasma source gas is used to generate plasma in the subsequent step ST2. The plasma source gas may be, for example, nitrogen (N ２ ), hydrogen (H ２), ammonia (NH ３ ), or a noble gas (e.g., argon (Ar)), but are not limited to these.

[0015] In the method MT1, step ST1 is performed after step STa. In step ST1, a first process is performed. The first process includes supplying a first process gas and plasma chemical species to a substrate. The first process gas includes a first borazine compound. In step ST1, a BN film is formed on the substrate by the first borazine compound. In step ST1, adsorption of the first borazine compound can be promoted by the plasma chemical species.

[0016] The first borazine compound and the second borazine compound used in step ST3 are compounds having a borazine ring as a basic skeleton, which includes three alternately bonded B (boron atoms) and three N (nitrogen atoms). The first borazine compound may be the same as or different from the second borazine compound.

[0017] The first borazine compound is borazine represented by the following formula (1), namely, cyclotriborazane (B ３ H ６ N ３ ) may also be used.

[0018] The first borazine compound may be an organic borazine compound in which some or all of the H atoms of borazine are substituted with organic ligands. The organic borazine compound may be an alkylborazine compound containing an alkyl group as an organic ligand. The alkylborazine compound may be N,N',N''-trimethylborazine (TMB) having a structure represented by the following formula (2):

[0019] The alkylborazine compound may include TMB, N,N',N''-triethylborazine, N,N',N''-tripropylborazine, N,N',N''-triisopropylborazine, or B,B',B''-triethyl-N,N',N''-trimethylborazine, or one or more of these. The borazine compound included in the first process gas functions as a B source and an N source for the BN film formed on the substrate.

[0020] In step ST1, plasma species are supplied to the substrate from plasma generated from a plasma source gas. The plasma species are supplied to the substrate in the chamber from plasma generated inside or outside the chamber. The plasma may be RF plasma obtained by exciting the plasma source gas using radio frequency (RF) power. Examples of RF plasma include capacitively coupled plasma (CCP), inductively coupled plasma (ICP), helicon wave plasma, and electron cyclotron resonance (ECR) plasma.

[0021] When a gas containing nitrogen atoms is used as the plasma source gas, nitrogen species (nitrogen radicals and / or nitrogen ions) in the plasma also function as an N source for the BN film. When a hexagonal BN film (h-BN film) is formed on a substrate, the energy of the plasma species can be adjusted so as not to destroy the basic skeleton of the first borazine compound.

[0022] After step ST1, step ST2 is performed. In step ST2, a second process is performed. The second process includes supplying plasma chemical species to the substrate without supplying a first process gas to the substrate. In step ST2, adsorption of the first borazine compound on the substrate to the substrate can be promoted. In step ST2, a reaction of forming a BN film from the first borazine compound can be promoted.

[0023] In step ST2, plasma may be generated from the same plasma source gas as the plasma source gas supplied into the chamber in step ST1, and plasma chemical species may be supplied to the substrate from the plasma. As shown in FIG. 1 , the plasma source gas may be supplied in steps STa, ST1, and ST2, and RF power may be applied to generate plasma in steps ST1 and ST2.

[0024] In the method MT1, a process STb is performed after the process ST2. In the process STb, the chamber is purged in the same manner as in the process STa.

[0025] As described above, in the method MT1, step ST3 is performed after the sequence SQ1 is performed x times (x≧1). As described above, step ST3 may be part of the sequence SQ2, and the sequence SQ2 may further include step STc.

[0026] In step ST3, a third process is performed. The third process includes supplying a second process gas containing a second borazine compound having an alkyl group to the substrate without supplying plasma chemical species to the substrate. In step ST3, the second borazine compound can be adsorbed onto the surface of the BN film.

[0027] The second borazine compound is, for example, a compound represented by the following general formula (3): １ or R ２ The second borazine compound may be an alkylborazine compound in which some or all of the groups are substituted with alkyl groups. The second borazine compound may be any of the alkylborazine compounds described above for the first borazine compound. The second borazine compound may be N,N',N-trimethylborazine (TMB) having the structure shown in formula (2) above.

[0028]

[0029] In the method MT1, a process STc is performed after the process ST3. In the process STc, the chamber is purged in the same manner as in the process STa.

[0030] In the method MT1, the cycle CY is repeated y times. The number of times y the cycle CY is performed may be determined in advance. Alternatively, the cycle CY may be repeated a number of times necessary for the thickness of the BN film on the substrate W to reach a predetermined thickness.

[0031] The second borazine compound adsorbed to the substrate in step ST3 has the effect of suppressing the growth of a BN film thereon (i.e., a growth-suppressing effect). Furthermore, in step ST3, the supply of the second process gas forms a distribution of the degree of the growth-suppressing effect on the surface of the substrate (see, for example, FIG. 7 ) provided by the protrusions. This distribution can be adjusted, for example, by the supply conditions of the second process gas in step ST3. In method MT1, the formation of the distribution of the degree of the growth-suppressing effect in step ST3 and the film formation in sequence SQ1 improve the step coverage (or conformality) of the BN film formed on the surface of the substrate.

[0032] 2 is a timing chart showing a method for forming a BN film according to another exemplary embodiment, in which the supply of various gases and the supply of radio frequency (RF) power in the film formation method according to one embodiment (hereinafter referred to as "method MT2") are indicated by solid or dotted lines with arrows.

[0033] Method MT2 differs from method MT1 in that it includes step ST2a, in which a second process is performed, before step ST1. Step ST2a is performed before step ST1 in sequence SQ1. In step ST2a, the second process is performed, similarly to step ST2. The other steps of method MT2 are similar to the corresponding steps of method MT1.

[0034] Like the sequence SQ1 of the method MT1, the sequence SQ1 of the method MT2 may further include step STa and step STb, or may include step STb without step STa. In the former case, i.e., when the sequence SQ1 of the method MT2 includes step STa, step ST2a may be performed between step STa and step ST1.

[0035] As shown in FIG. 2, the plasma source gas may be supplied during steps STa, ST2a, ST1, and ST2, and RF power for generating plasma may be supplied during steps ST2a, ST1, and ST2.

[0036] Since the method MT2 further includes step ST2a, it is possible to ensure a long supply time of the plasma chemical species. In the method MT2, step ST2a may be performed for the purpose of improving the flatness of the surface of the BN film formed on the surface of the substrate.

[0037] 3 is a timing chart showing a method for forming a BN film according to yet another example embodiment, in which the supply of various gases and the supply of radio frequency (RF) power in one embodiment of the method (hereinafter referred to as "method MT3") are indicated by solid or dotted lines with arrows.

[0038] Method MT3 differs from method MT1 in that it includes step STd instead of step STa. That is, in method MT3, step STd is performed before step ST1. The other steps of method MT2 are the same as the corresponding steps of method MT1.

[0039] In step STd, a pre-flow is performed. The pre-flow includes supplying a first process gas to the substrate without supplying plasma chemical species. In step STd, a plasma source gas may be supplied into the chamber. The plasma source gas is used to generate plasma from the plasma source gas in the subsequent step ST1. In step STd, a purge gas may be supplied into the chamber.

[0040] As shown in FIG. 3, the plasma source gas may be supplied during the steps STd, ST1, and ST2, and RF power may be applied and supplied during the steps ST1 and ST2 to generate plasma.

[0041] Since the method MT3 further includes step STd, the supply time of the first process gas can be secured for a long time. In the method MT3, step STd can be performed for the purpose of further improving the step coverage of the BN film formed on the surface of the substrate.

[0042] The deposition conditions for forming a BN film on a substrate in each cycle CY of the above-described methods MT1 to MT3 may include at least one of the substrate processing temperature, the pressure in the chamber, the supply time of the first processing gas and plasma in step ST1 (depo time), the supply time of plasma in step ST2, the supply time of the second processing gas in step ST3, and the supply flow rate of the second processing gas in step ST3. By setting these conditions to predetermined conditions, the conformality of the BN film on the surface of the substrate can be improved in accordance with the shape of the surface of the substrate.

[0043] Furthermore, the supply time of the second process gas in step ST3 of each of the methods MT1 to MT3 may be shorter than the deposition time in step ST1. In this case, the second borazine compound effectively suppresses the growth of the BN film. Therefore, the step coverage of the BN film can be further improved.

[0044] Furthermore, the supply flow rate of the second process gas in step ST3 of each of the methods MT1 to MT3 may be smaller than the supply flow rate of the first process gas in step ST1. In this case, the growth suppression effect of the second borazine compound is also effectively exerted. Therefore, the step coverage of the BN film can be further improved.

[0045] The first borazine compound used in each of methods MT1 to MT3 may contain an alkyl group. The first borazine compound may be the same as the second borazine compound. In this case, a BN film can be easily formed using a single borazine compound in methods MT1 to MT3.

[0046] In methods MT1 to MT3, the supply time of the second process gas in step ST3 may be 0.5 seconds or less. By adjusting the supply time of the second process gas in step ST3 within a range of 0.5 seconds or less, the growth suppression effect of the second borazine compound can be adjusted. Therefore, this BN film formation method makes it possible to form a BN film with higher step coverage. The supply time of the second process gas in step ST3 may be 0.1 seconds or less.

[0047] In addition, in methods MT1 to MT3, by adjusting the processing temperature of the substrate, the pressure in the chamber, and the deposition time, it is possible to form a BN film with a hexagonal crystal structure (h-BN) or a BN film with an amorphous structure (a-BN).

[0048] Here, the results of investigating whether an h-BN film or an a-BN film was formed by performing sequence SQ1 of method MT1 while changing the substrate processing temperature, the pressure in the chamber, and the deposition time are shown. In this investigation, the film formation apparatus shown in FIG. 6, which will be described later, was used. In addition, TMB gas was used as the source gas, and N was used as the plasma source gas. ２ Gas was used. The pressure in the chamber was changed in the range of 1.5 to 8 Torr, the processing temperature of the substrate (or the temperature of the mounting table 2) was changed in the range of 200°C to 400°C, and the Depo Time was set to 2 seconds and 4 seconds, respectively. The TMB flow rate was 20 sccm, and the RF power was 400 W. The times for steps STa and STb were set to 3 seconds, and the time for step ST2 was set to 4 seconds.

[0049] Fig. 4 is a diagram showing whether h-BN or a-BN is deposited at different chamber pressures and substrate processing temperatures when the deposition time is set to 2 seconds. Fig. 5 is a diagram showing whether h-BN or a-BN is deposited at different chamber pressures and substrate processing temperatures when the deposition time is set to 4 seconds.

[0050] 4 and 5, a-BN is more likely to form a film under low temperature and low pressure conditions, and h-BN is more likely to form a film under high temperature and high pressure conditions. Furthermore, the longer the depo time, the more likely a-BN is to form a film, and the more difficult it is for h-BN to form a film.

[0051] In methods MT1 to MT3, the deposition time may be set to 4 seconds or more, the pressure in the chamber may be set to 8 torr (800 Pa) or more, and the substrate temperature may be set to 200° C. or more. In this case, an h-BN film can also be formed.

[0052] <Boron Nitride Film Forming Apparatus> Figure 6 is a diagram showing the configuration of a BN film forming apparatus according to one example embodiment. The film forming apparatus 100 shown in Figure 6 is a film forming apparatus that can be used to form a BN film in methods MT1 to MT3. The film forming apparatus 100 includes a chamber 1, a gas supply mechanism 5, a plasma generating unit 6, and a control unit 7. The film forming apparatus 100 may further include a mounting table 2, a shower head 3, and an exhaust unit 4.

[0053] The chamber 1 is capable of accommodating a substrate W. The chamber 1 is made of a metal such as aluminum and has a substantially cylindrical shape. A loading / unloading port 11 for loading and unloading the substrate W is formed in a side wall of the chamber 1, and the loading / unloading port 11 can be opened and closed by a gate valve 12. An annular exhaust duct 13 with a rectangular cross section is provided on the main body of the chamber 1.

[0054] A slit 13a is formed along the inner peripheral surface of the exhaust duct 13. An exhaust port 13b is formed in the outer wall of the exhaust duct 13. A ceiling wall 14 is provided on the upper surface of the exhaust duct 13 to close the upper opening of the chamber 1. A seal ring 15 provides an airtight seal between the ceiling wall 14 and the exhaust duct 13.

[0055] The mounting table 2 is a table on which the substrate W can be placed in a horizontal position, has a disk shape corresponding in size to the substrate W, and is supported by a support member 23. The mounting table 2 is made of a ceramic material such as aluminum nitride (AlN) or a metal material such as aluminum or a nickel-based alloy, and has a heater 21 embedded therein for heating the substrate W. A cover member 22 is provided on the mounting table 2 so as to cover the side surface.

[0056] The support member 23 that supports the mounting table 2 extends from the center of the bottom surface of the mounting table 2 to below the chamber 1, passing through a hole formed in the bottom wall of the chamber 1, and its lower end is connected to the mounting table lifting mechanism 24. The mounting table lifting mechanism 24 enables the mounting table 2 to be raised and lowered via the support member 23 between a processing position shown by a solid line and a transport position shown by a dotted line below that, where a substrate can be transported.

[0057] A flange 25 is attached to the support member 23 below the chamber 1, and a bellows 26 is provided between the bottom surface of the chamber 1 and the flange 25 to separate the atmosphere inside the chamber 1 from the outside air and to expand and contract as the mounting table 2 moves up and down.

[0058] Three substrate support pins 27 (only two are shown) are provided near the bottom surface of the chamber 1 so as to protrude upward from an elevation plate 27a. The substrate support pins 27 can be raised and lowered via the elevation plate 27a by a substrate support pin elevation mechanism 28 provided below the chamber 1, and are inserted into through holes 2a provided in the mounting table 2 at the transfer position, so that they can protrude and retract relative to the upper surface of the mounting table 2.

[0059] By raising and lowering the substrate support pins 27 in this manner, the substrate W is transferred between a substrate transport mechanism (not shown) and the mounting table 2. A bellows 28a is provided between the bottom surface of the chamber 1 and the substrate support pin lifting mechanism 28.

[0060] The shower head 3 supplies a process gas into the chamber 1 in a shower-like manner. The shower head 3 is disposed opposite the mounting table 2 and has approximately the same diameter as the mounting table 2. The shower head 3 has a shower body 31 fixed to the ceiling wall 14 of the chamber 1 and a shower plate 32 connected below the shower body 31.

[0061] A gas diffusion space 33 is formed between the shower body 31 and the shower plate 32, and a gas inlet hole 36 is connected to this gas diffusion space 33. The gas inlet hole 36 penetrates the shower body 31 and the center of the ceiling wall 14 of the chamber 1. Gas outlet holes 34 are formed in the shower plate 32. When the mounting table 2 is in the processing position, a processing space S is formed between the shower plate 32 and the mounting table 2.

[0062] The exhaust unit 4 includes an exhaust pipe 41 connected to the exhaust port 13b of the exhaust duct 13, an automatic pressure control (APC) valve 42 connected to the exhaust pipe 41, and an exhaust mechanism 43 having a vacuum pump. During processing, gas inside the chamber 1 reaches the exhaust duct 13 through the slit 13a and is exhausted from the exhaust duct 13 through the exhaust pipe 41 by the exhaust mechanism 43 of the exhaust unit 4.

[0063] The gas supply mechanism 5 supplies gases used for film formation to the shower head 3. That is, the gas supply mechanism 5 can supply the above-mentioned first process gas, second process gas, plasma source gas, and purge gas to the processing space S in the chamber 1 via the shower head 3.

[0064] The gas supply mechanism 5 includes a first process gas supply source 51, a second process gas supply source 52, a plasma source gas supply source 53, and purge gas supply sources 54 and 55. The purge gas may be, for example, a rare gas.

[0065] One end of a gas line 51a is connected to the supply source 51. A valve 51b, a filter tank 51c, and a flow rate regulator 51d are installed in the gas line 51a in this order from the downstream side.

[0066] One end of a gas line 52a is connected to the supply source 52. A valve 52b, a filter tank 52c, and a flow rate regulator 52d are installed in the gas line 52a, in this order from the downstream side. The gas lines 51a and 52a merge downstream of the valves 51b and 52b and are connected to one end of a gas line 56.

[0067] One end of a gas line 53a is connected to the supply source 53. A valve 53b, a filter tank 53c, and a flow rate regulator 53d are installed in the gas line 53a, in this order from downstream. The gas line 56 and the gas line 53a are connected to one end of a gas line 57. The other end of the gas line 57 is connected to the gas inlet 36 of the showerhead 3.

[0068] One end of a gas line 54a is connected to the supply source 54. A valve 54b and a flow rate regulator 54d are disposed in the gas line 54a in this order from the downstream side. The other end of the gas line 54a is connected to a gas line 56.

[0069] One end of a gas line 55a is connected to the supply source 55. A valve 55b and a flow rate regulator 55d are disposed in the gas line 55a in this order from the downstream side. The other end of the gas line 55a is connected to the gas line 53a downstream of the valve 53b.

[0070] Valves 54b and 55b are constantly open during the BN film formation process in film formation apparatus 100. Furthermore, during the film formation process, purge gas from gas lines 54a and 55a is constantly supplied into chamber 1 via gas lines 56 and 53a.

[0071] The valves 51b, 52b, and 53b are configured as high-speed on-off valves that open and close the corresponding gas lines at high speed, while the valves 54b and 55b are normal on-off valves.

[0072] The fill tank 51 c, the fill tank 52 c, and the fill tank 53 c temporarily store the first process gas, the second process gas, and the plasma source gas, respectively, before they are supplied into the chamber 1.

[0073] By storing gas in fill tank 51c, fill tank 52c, or fill tank 53c, the pressure therein can be increased to a predetermined level, and then by opening valve 51b, 52b, or 53b, the gas can be discharged into chamber 1. This allows a large flow rate of gas to be stably supplied to chamber 1.

[0074] The flow rate adjusting units 51d, 52d, 53d, 54d, and 55d are configured by, for example, mass flow controllers, and adjust and control the flow rates of gases flowing through the corresponding gas lines.

[0075] The plasma generation unit 6 has a power supply line 61 connected to the shower body 31 of the showerhead 3, and a matching box 62 and a radio frequency (RF) power supply 63 connected to the power supply line 61. When radio frequency (RF) power is supplied from the RF power supply 63 to the showerhead 3, a radio frequency (RF) electric field is formed in the processing space S between the showerhead 3 and the mounting table 2, and this RF electric field generates plasma of the plasma source gas as capacitively coupled plasma. If the mounting table 2 is made of a ceramic material, an electrode is embedded in the mounting table 2, and an RF electric field is formed between the showerhead 3 and the electrode.

[0076] The supply source 53 and the plasma generating unit 6 function as a plasma supply mechanism that generates plasma from a plasma source gas and supplies plasma chemical species from the plasma to the substrate W.

[0077] The control unit 7 is configured by a computer and includes a main control unit with a CPU, an input device, an output device, a display device, and a storage device (storage medium). The main control unit controls components of the film forming apparatus 100, such as valves, flow rate regulators, automatic pressure control valves, heaters, and lifting mechanisms.

[0078] The storage device stores parameters for various processes executed by the film forming apparatus 100. The storage device also has a storage medium that stores programs for controlling the processes executed by the film forming apparatus 100, i.e., process recipes. The main control unit calls up a predetermined process recipe stored in the storage medium and causes the film forming apparatus 100 to perform a predetermined operation based on the process recipe.

[0079] The control unit 7 is configured to control the gas supply mechanism 5 and the plasma generating unit 6 to repeat the cycle CY while the substrate W is accommodated in the chamber 1, thereby performing the film formation process of the BN film.

[0080] An example of a film formation method using the above-described film formation apparatus 100 will be described below. In one example, first, a substrate W is prepared in the chamber 1 of the film formation apparatus 100. Specifically, the gate valve 12 is opened, and the substrate W is loaded into the chamber 1. The substrate W is loaded by a transfer device (not shown) through the load / unload port 11. The loaded substrate W is placed on the mounting table 2. Next, the transfer device is retracted from the space within the chamber 1, and the mounting table 2 is raised to a processing position. Then, the gate valve 12 is closed, and the chamber 1 is evacuated. Thereafter, the mounting table 2 is heated by the heater 21, and the temperature of the mounting table 2 (substrate temperature) is adjusted to a desired temperature.

[0081] A film formation process can be started in this state where the substrate W is prepared in the chamber 1 of the film formation apparatus 100. An example of a film formation process in the case where the method MT1 is performed as shown in FIG.

[0082] First, in step STa, the chamber 1 is purged. In step STa, a purge gas may be supplied from the supply source 54 and the supply source 55 to the processing space S via the gas line 54 a, the gas line 55 a, and the shower head 3. The purge gas may be continuously supplied during sequences SQ1 and SQ2.

[0083] In the process STa, the first process gas may be flowed into an exhaust line of the film forming apparatus 100. Alternatively, in the process STa, the first process gas may be filled into a fill tank of the film forming apparatus 100. In addition, in the process STa, a plasma source gas may be supplied into the chamber 1.

[0084] After step STa, step ST1 is performed. In step ST1, a first process is performed. In step ST1, a first process gas can be supplied from a supply source 51 to the processing space S via a gas line 51a and the shower head 3. Furthermore, a plasma source gas is supplied from a supply source 53 to the processing space S via a gas line 53a and the shower head 3, and RF power is supplied from an RF power source 63 of the plasma generation unit 6 to the shower head 3. As a result, the first process gas and plasma chemical species are supplied to the substrate W.

[0085] After the process ST1, a process ST2 is performed. In the process ST2, a second process is performed. In the process ST2, plasma chemical species are supplied to the substrate W. In addition, in the process ST2, the valve 51b is closed to stop the supply of the first process gas.

[0086] After process ST2, process STb is performed. In process STb, the chamber is purged in the same manner as in process STa. In process STb, the supply of RF power from the RF power supply 63 is stopped, and the valve 53b is closed to stop the supply of plasma source gas. This creates a state in which only the purge gas is supplied to the processing space S, and the chamber 1 is purged.

[0087] In step ST3, a third process is performed. In step ST3, a second process gas may be supplied from the supply source 52 to the processing space S via the gas line 52a and the shower head 3. In step ST3, a purge gas may be supplied.

[0088] Next, process STc is performed. In process STc, the chamber 1 is purged in the same manner as in process STa. In process STc, the valve 52b is closed to stop the supply of the second process gas. This creates a state in which only the purge gas is supplied to the processing space S, and the chamber 1 is purged.

[0089] In the above-described method MT2, after step STa of purging the chamber 1, step ST2a of supplying plasma chemical species to the substrate W is performed. In step ST2a, while a plasma source gas is being supplied to the processing space S, RF power is supplied from the RF power supply 63 of the plasma generation unit 6 to the shower head 3.

[0090] In the above-described method MT3, a preflow process (process STd) is performed instead of process ST1, in which a first process gas is supplied to the processing space S in addition to a purge gas (or a purge gas and a plasma source gas). In process STd, the first process gas can be supplied from the supply source 51 to the processing space S via the gas line 51 a and the shower head 3.

[0091] Although various exemplary embodiments have been described above, the present invention is not limited to the above-described exemplary embodiments, and various additions, omissions, substitutions, and modifications may be made. Furthermore, elements in different embodiments may be combined to form other embodiments.

[0092] For example, although methods MT1, MT2, and MT3 have been described as examples of methods for forming a BN film, methods other than these film formation processes can also be adopted. That is, sequence SQ1 may include step ST1 of supplying a first process gas containing a first borazine compound and plasma chemical species to a substrate accommodated in a chamber, and step ST2 of supplying plasma chemical species to the substrate without supplying the first process gas. Sequence SQ2 may include step ST3 of supplying a second process gas to the substrate without supplying plasma chemical species.

[0093] Furthermore, in the BN film forming apparatus 100, a supply source 51 and a supply source 52 are provided as supply mechanisms for the first and second process gases, respectively. However, the supply mechanisms for the first and second process gases do not need to be composed of multiple supply mechanisms, and may be composed of a single supply mechanism. For example, when both the first borazine compound and the second borazine compound are TMB, a single supply source can be used as the supply mechanism for the first and second process gases.

[0094] Furthermore, the BN film deposition apparatus may be a deposition apparatus other than a single-wafer deposition apparatus, for example, a batch deposition apparatus. Furthermore, the BN film deposition apparatus is not limited to a capacitively coupled plasma processing apparatus. For example, the BN film deposition apparatus may be any type of plasma processing apparatus, such as an inductively coupled plasma processing apparatus or a surface wave plasma processing apparatus configured to generate plasma using surface waves such as microwaves. Furthermore, the BN film deposition apparatus may be a remote plasma plasma processing apparatus configured to supply plasma generated at a different location to the substrate.

[0095] <Evaluation Experiment> Hereinafter, an experiment conducted to evaluate the formation of the BN film will be described.

[0096] 7 is a schematic diagram of a cross-sectional TEM image of a sample substrate WP after formation of a BN film in an experiment. As shown in FIG. 7, the sample substrate WP was a substrate including a base region B made of silicon and a protrusion PR made of silicon oxide and extending upward from the base region B. In the experiment, a BN film F was formed on the surface of the sample substrate WP. The protrusion PR had a structure including a pair of side surfaces and an upper surface extending from the upper ends of the side surfaces.

[0097] In the experiment, the thickness W of the BN film F at the top surface, i.e., the top T Ｔ , the thickness W of the BN film F at the intermediate portion Md in the height direction of the side surface of the protrusion PR Ｍ , the thickness W of the BN film F at the bottom Bt of the side surface of the protrusion PR Ｂ Then, W Ｔ W against Ｍ Percentage (%) and W Ｔ W against Ｂ The percentage (%) of "W Ｍ / W Ｔ " is W Ｔ W against Ｍ The ratio of "W Ｂ / W Ｔ " is W Ｔ W against Ｂ Indicates the percentage of.

[0098] In the following experimental examples and comparative experimental examples, N,N',N''-trimethylborazine (TMB) was used as the first process gas and the second process gas, and NH ３ The BN film F was formed using the gas as the purging gas and Ar gas as the purging gas.

[0099] (Comparative Experimental Example) In the comparative experimental example, a sample substrate WP was subjected to the film formation process described below to form a BN film F on the sample substrate WP. In the comparative experimental example, a sequence of performing, in this order, a first process (step ST1) of supplying TMB gas and plasma chemical species to the sample substrate WP, a second process (step ST2) of supplying plasma chemical species to the sample substrate WP without supplying TMB gas, and a purge process (step STb) of purging the chamber was repeated until a BN film F with a predetermined thickness was obtained.

[0100] Details of the processing conditions in the comparative experimental example are shown below. In the following, Depo time is the time of the first processing (step ST1), Plasma time is the time of the second processing (step ST2), and Purge time is the time of the purge step (step STb).

[0101] Substrate temperature: 400°C Stage gap: 6 mm Pressure: 6 torr (800 Pa) TMB flow rate: 20 sccm NH ３ Flow rate: 3000sccm Depo time: 2 seconds Plasma time: 16 seconds Purge time: 6 seconds RF power: 400W CF-Ar flow rate: 1500sccm Bottom Ar flow rate: 100sccm

[0102] In the film forming method of this comparative example, W Ｍ / W Ｔ = 46%, W Ｂ / W Ｔ The result was 43%.

[0103] Experimental Example 1 In Experimental Example 1, a sample substrate WP was subjected to the film formation process of method MT1 to form a BN film F on the sample substrate WP.

[0104] In sequence SQ1 of Experimental Example 1, a first process (step ST1) of supplying TMB gas and plasma species to the sample substrate WP, a second process (step ST2) of supplying plasma species to the sample substrate WP without supplying TMB gas, and a purge process (step STb) of purging the chamber were performed in this order. In sequence SQ2, a third process (step ST3) of supplying TMB gas without supplying plasma species, and a purge process (step STc) of purging the chamber were performed in this order.

[0105] Details of the processing conditions in Experimental Example 1 are shown below. In the following, Flow time is the time of the third processing (step ST3), and x is the number of times the sequence SQ1 is performed in one cycle (cycle CY).

[0106] Substrate temperature: 400° C. Stage gap: 6 mm Pressure: 6 torr (800 Pa) TMB flow rate (step ST1): 20 sccm TMB flow rate (step ST3): 10 sccm NH ３ Flow rate: 3000sccm Depo time: 2 seconds Plasma time: 16 seconds Purge time: 6 seconds Flow time: 0.1 seconds RF power: 400W CF-Ar flow rate: 1500sccm Bottom Ar flow rate: 100sccm x: 5

[0107] In the film forming method according to Experimental Example 1, W Ｍ / W Ｔ = 55%, W Ｂ / W Ｔ The result was 49%. Ｍ / W Ｔ and W Ｂ / W Ｔ All of the values ​​were superior to those of the comparative experiment, confirming that the step coverage was improved.

[0108] Experimental Example 2 In Experimental Example 2, the pressure in Experimental Example 1 was changed from 6 torr (800 Pa) to 11 torr (1467 Pa), and x was changed from 5 to 1, and an experiment similar to Experimental Example 1 was performed.

[0109] In the film forming method according to Experimental Example 2, W Ｍ / WＴ = 53%, W Ｂ / W Ｔ In Experimental Example 2, the result was W = 47%. Ｍ / W Ｔ and W Ｂ / W Ｔ The numerical value was superior to that of the comparative experiment, and it was confirmed that the step coverage was improved.

[0110] From the above results, it was confirmed that the film forming process including the third process (step ST3) in sequence SQ2 improved the step coverage.

[0111] In Experimental Examples 1 and 2, it is believed that the above-mentioned growth suppression effect was particularly pronounced at the top T of the protrusion PR. In addition to the above-mentioned Experimental Examples 1 and 2, an experiment was also carried out to measure the growth suppression effect of the BN film. Figure 8 shows the results of an experiment measuring the growth suppression effect of the BN film.

[0112] In this experiment, the amount of BN film formed per sequence (change in film thickness) was defined as GPC, and the ratio of GPC in Experimental Example 1 and Experimental Example 2 to GPC in the Comparative Experimental Example was calculated. Calculations were performed for each of the top T, middle side Ms, and bottom side Bs of the protrusion PR. As shown in Figure 8, in both Experimental Example 1 and Experimental Example 2, the GPC at the top T was smaller than that of the Comparative Experimental Example. This result shows that the growth inhibition effect was significantly exerted at the top T of the protrusion PR.

[0113] (Experimental Example 3) In Experimental Example 3, the number x of sequence SQ1 in one cycle was changed to various values, and GPC was measured to evaluate the change in the growth inhibition effect depending on the number x of sequence SQ1. In Experimental Example 3, instead of the sample substrate WP schematically shown in FIG. 7, another sample substrate (not shown) having a flat surface was used to evaluate the growth inhibition effect of the BN film on the flat surface. In Experimental Example 3, the flow time, which is the time for the third treatment (step ST3), was set to 1 second. The other conditions in Experimental Example 3 were the same as the corresponding conditions in Experimental Example 1.

[0114] 9 shows the results of an experiment that measured the relationship between the number x of sequence SQ1 in one cycle and GPC. In FIG. 9, "w / o" indicates the results of an experiment in which only sequence SQ1 was performed. As shown in FIG. 9, the smaller the value of x, the smaller the GPC. In other words, it was confirmed that the smaller the value of x, the more frequently sequence SQ2 is performed, and therefore the effect of suppressing the growth of the BN film is significantly exhibited.

[0115] (Experimental Example 4) In Experimental Example 4, using the same sample substrate as in Experimental Example 3, GPC was measured while changing the time (Flow time) of the third process (step ST3) in sequence SQ2. In Experimental Example 4, the number x of times sequence SQ1 was performed in one cycle was 5. The other conditions in Experimental Example 4 were the same as the corresponding conditions in Experimental Example 1.

[0116] 10 is a diagram showing the results of an experiment measuring the relationship between flow time and GPC. As shown in FIG. 10, when the flow time is between 0.1 and 0.5 seconds, the GPC decreases as the flow time increases. Even when the flow time is 0.5 seconds or longer, there is an effect of suppressing the growth of the BN film, but this effect is saturated, and it was confirmed that the GPC does not change even when the flow time is increased.

[0117] Therefore, it was confirmed that the growth inhibitory effect can be adjusted to a desired level by changing the flow time by 0.5 seconds or less.

[0118] (Experimental Example 5) In Experimental Example 5, using the same sample substrate as in Experimental Example 3, GPC was measured while changing the flow rate of TMB in step ST3 of sequence SQ2, and the relationship between the TMB flow rate in step ST3 and the growth inhibitory effect was evaluated. GPC measurements were performed for two patterns: when the flow time was 0.1 seconds and when it was 1 second. In Experimental Example 5, the number x of times sequence SQ1 was performed in one cycle was 5. The other conditions in Experimental Example 5 were the same as the corresponding conditions in Experimental Example 1.

[0119] 11 is a diagram showing the results of an experiment measuring the relationship between the flow rate of TMB in step ST3 and GPC. As shown in FIG. 11, it can be seen that the GPC does not change with the change in the flow rate of TMB in step ST3, whether the flow time is 1 second or 0.1 second.

[0120] Therefore, it was confirmed that the growth suppression effect was sufficiently exhibited when the TMB flow rate was set to 5 sccm. Furthermore, it was confirmed that when the TMB flow rate in step ST3 was set to be smaller than the TMB flow rate in step ST1, as in Experimental Example 5, the BN film growth suppression effect could be obtained regardless of the TMB flow rate.

[0121] <Effect of Pressure in Step ST3> Figure 12 is a diagram showing the results of an experiment measuring the relationship between the pressure in step ST3 and GPC using the same sample substrate as in Experimental Example 3. In the legend, "x" means the number of sequences SQ1 in one cycle, and "flow" means flow time. In the four experiments whose measurement results are shown in Figure 12, the conditions other than x and flow time are the same as the corresponding conditions in Experimental Example 1.

[0122] As shown in FIG. 12, it was confirmed that the GPC tends to improve as the pressure in step ST3 increases.

[0123] In Experimental Example 6, the same sample substrate as in Experimental Example 3 was used, and the number x of sequences SQ1 in one cycle was set to 1, the flow time was set to 0.1 seconds, and the relationship between the pressure in step ST3 and GPC was measured. The other conditions in Experimental Example 6 were the same as the corresponding conditions in Experimental Example 1.

[0124] 13 is a diagram showing the results of an experiment measuring the relationship between the pressure in step ST3 and GPC. As shown in FIG. 13, the higher the pressure in step ST3, the more improved the GPC. Therefore, it was confirmed that the effect of suppressing the growth of the BN film can be adjusted by adjusting the pressure in step ST3.

[0125] 12 and 13, it was confirmed that pressure dependence occurs in GPC depending on the number of sequences SQ1 in one cycle x or the value of Flow time. Therefore, it was confirmed that under the values ​​of x and Flow time at which pressure dependence occurs in GPC, it is possible to adjust the growth suppression effect of the BN film by adjusting the pressure.

[0126] Various exemplary embodiments included in the present disclosure are now described in [E1] to [E18] below.

[0127] [E1] A method for forming a boron nitride film, comprising: (a) a step of executing a sequence, the sequence comprising: (a1) a step of supplying a first process gas containing a first borazine compound and plasma species to a substrate placed in a chamber of a film formation apparatus in order to form a boron nitride film on the substrate; (a2) a step of supplying the plasma species to the substrate without supplying the first process gas to the substrate; (b) a step of supplying a second process gas containing a second borazine compound having an alkyl group to the substrate without supplying the plasma species to the substrate; and (c) a step of repeating a cycle comprising the steps (a) and (b).

[0128] [E2] The method of forming a boron nitride film according to E1, wherein the film formation conditions for forming the boron nitride film on the substrate in the cycle include at least one of a processing temperature of the substrate, a pressure in the chamber, a supply time of the first processing gas and the plasma chemical species in (a1), a supply time of the plasma chemical species in (a2), a supply time of the second processing gas in (b), and a supply flow rate of the second processing gas in (b).

[0129] [E3] The method for forming a boron nitride film according to E1 or E2, wherein the supply time of the second process gas in (b) is shorter than the supply time of the first process gas and the plasma chemical species in (a1).

[0130] [E4] The method for forming a boron nitride film according to E1 or E2, wherein the supply flow rate of the second process gas in (b) is smaller than the supply flow rate of the first process gas in (a1).

[0131] [E5] The method for forming a boron nitride film according to any one of E1 to E4, wherein the sequence further includes a step of purging the chamber after (a1) and (a2), and the cycle further includes a step of purging the chamber after (b).

[0132] [E6] The method for forming a boron nitride film according to any one of E1 to E4, wherein the sequence further comprises: before (a1), supplying the plasma chemical species to the substrate without supplying the first process gas to the substrate; and after (a1) and (a2), purging the chamber, and the cycle further comprises purging the chamber after (b). [E7] The method for forming a boron nitride film according to any one of E1 to E4, wherein the sequence further comprises: before (a1), supplying the first process gas to the substrate without supplying the plasma to the substrate; and after (a1) and (a2), purging the chamber, and the cycle further comprises purging the chamber after (b).

[0133] [E8] The method for forming a boron nitride film according to any one of E1 to E8, wherein the first borazine compound contains an alkyl group.

[0134] [E9] The method for forming a boron nitride film according to E8, wherein the first borazine compound is the same as the second borazine compound.

[0135] [E10] The method for forming a boron nitride film according to E9, wherein the first borazine compound and the second borazine compound are N,N',N''-trimethylborazine.

[0136] [E11] The method for forming a boron nitride film according to any one of E1 to E10, wherein the plasma chemical species is a plasma chemical species generated from a gas containing at least one selected from the group consisting of nitrogen, hydrogen, and a rare gas.

[0137] [E12] The plasma species is N ２ , H ２ and N.H. ３ The method for forming a boron nitride film according to E11, wherein the plasma species generated from the gas includes at least one selected from the group consisting of:

[0138] [E13] The plasma species is NH ３ The method for forming a boron nitride film according to E12, wherein the plasma species generated from the gas includes:

[0139] [E14] The method for forming a boron nitride film according to any one of E1 to E13, wherein the supply time of the second process gas in (b) is 0.5 seconds or less.

[0140] [E15] The method for forming a boron nitride film according to E14, wherein the supply time of the second process gas in (b) is 0.1 seconds or less.

[0141] [E16] The method for forming a boron nitride film according to any one of E1 to E15, wherein the surface of the substrate on which the boron nitride film is formed includes a side surface and an upper surface of a protrusion extending upward from an underlying region.

[0142] [E17] The method for forming a boron nitride film according to any one of E1 to E16, wherein in (a1), a supply time of the first process gas and the plasma chemical species, a pressure in the chamber, and a processing temperature of the substrate are set to predetermined supply times, pressures, and temperatures so as to form a hexagonal boron nitride film as the boron nitride film.

[0143] [E18] A film formation apparatus comprising: a chamber; a gas supply mechanism connected to the chamber; a plasma generation unit configured to generate plasma from a gas in the chamber; and a control unit, wherein the control unit controls the gas supply mechanism and the plasma generation unit with a substrate accommodated in the chamber to perform a film formation process for a boron nitride film, the sequence including: (a) a step of executing a sequence including: (a1) a step of supplying a first process gas containing a first borazine compound and plasma species to the substrate; and (a2) a step of supplying the plasma species to the substrate without supplying the first process gas to the substrate; and (b) a step of supplying a second process gas containing a second borazine compound having an alkyl group to the substrate without supplying the plasma species to the substrate; and (c) a step of repeating a cycle including the steps (a) and (b).

[0144] From the foregoing, it will be understood that various embodiments of the present disclosure have been described herein for purposes of illustration, and that various changes may be made without departing from the scope and spirit of the present disclosure. Accordingly, the various embodiments disclosed herein are not intended to be limiting, with the true scope and spirit being indicated by the appended claims.

[0145] 1...chamber, 2...mounting table, 3...shower head, 4...exhaust section, 5...gas supply mechanism, 6...plasma generating section, 7...control section, 51 to 55...supply sources, 100...film forming apparatus, W...substrate

Claims

1. (a) A step of executing a sequence, the sequence including: (a1) A step of supplying a first processing gas containing a first borazine compound and plasma chemical species to a substrate to form a boron nitride film on the substrate disposed in a chamber of a film forming apparatus; (a2) A step of supplying the plasma chemical species to the substrate without supplying the first processing gas to the substrate; and the step, and (b) A step of supplying a second processing gas containing a second borazine compound containing an alkyl group to the substrate without supplying the plasma chemical species to the substrate; (c) A step of repeating a cycle including the above (a) and (b). A method for forming a boron nitride film including the above steps.

2. The film forming conditions for forming the boron nitride film on the substrate in the cycle include at least one of the processing temperature of the substrate, the pressure in the chamber, the supply time of the first processing gas and the plasma chemical species in (a1), the supply time of the plasma chemical species in (a2), the supply time of the second processing gas in (b), and the supply flow rate of the second processing gas in (b). The method for forming a boron nitride film according to claim 1.

3. The method for forming a boron nitride film according to claim 1 or 2, wherein the supply time of the second processing gas in (b) is shorter than the supply time of the first processing gas and the plasma chemical species in (a1).

4. The method for forming a boron nitride film according to claim 1 or 2, wherein the supply flow rate of the second processing gas in (b) is smaller than the supply flow rate of the first processing gas in (a1).

5. The sequence further includes a step of purging the chamber after (a1) and (a2), and the cycle further includes a step of purging the chamber after (b). The method for forming a boron nitride film according to claim 1 or 2.

6. The sequence further includes: Before (a1), a step of supplying the plasma chemical species to the substrate without supplying the first processing gas to the substrate; After (a1) and (a2), a step of purging the chamber; and the cycle further includes a step of purging the chamber after (b). The method for forming a boron nitride film according to claim 1 or 2.

7. The sequence further includes, before the step (a1), a step of supplying the first processing gas to the substrate without supplying the plasma to the substrate, and after the steps (a1) and (a2), a step of purging the chamber. The cycle further includes a step of purging the chamber after the step (b). The method for forming a boron nitride film according to claim 1 or 2.

8. The method for forming a boron nitride film according to claim 1 or 2, wherein the first borazine compound contains an alkyl group.

9. The method for forming a boron nitride film according to claim 8, wherein the first borazine compound is the same as the second borazine compound.

10. The method for forming a boron nitride film according to claim 9, wherein the first borazine compound and the second borazine compound are N,N',N''-trimethylborazine.

11. The method for forming a boron nitride film according to claim 1 or 2, wherein the plasma chemical species is a plasma chemical species generated from a gas containing at least one selected from the group consisting of nitrogen, hydrogen, and a rare gas.

12. The plasma chemical species is N ２ , H ２ and NH ３ The method for forming a boron nitride film according to claim 11, which is a plasma chemical species generated from the gas containing at least one selected from the group consisting of 13. The plasma chemical species is a plasma chemical species generated from the gas containing NH ３ The method for forming a boron nitride film according to claim 12, wherein the method is a plasma chemical species generated from the gas containing 14. The method for forming a boron nitride film according to claim 1 or 2, wherein the supply time of the second processing gas in the step (b) is 0.5 seconds or less.

15. The method for forming a boron nitride film according to claim 14, wherein the supply time of the second processing gas in the step (b) is 0.1 seconds or less.

16. The surface of the substrate on which the boron nitride film is formed includes the side surface of a protrusion extending upward from a base region and the upper surface of the protrusion. The method for forming a boron nitride film according to claim 1.

17. In the step (a1), the supply time of the first processing gas and the plasma chemical species, the pressure in the chamber, and the processing temperature of the substrate are set to a predetermined supply time, pressure, and temperature so as to form a hexagonal boron nitride film as the boron nitride film. The method for forming a boron nitride film according to claim 1 or 16.

18. A film forming apparatus comprising a chamber, a gas supply mechanism connected to the chamber, a plasma generation unit configured to generate plasma from a gas in the chamber, and a control unit, wherein the control unit controls the gas supply mechanism and the plasma generation unit in a state where a substrate is accommodated in the chamber to perform: (a) a step of executing a sequence, the sequence including: (a1) a step of supplying a first processing gas containing a first borazine compound and plasma chemical species to the substrate; (a2) a step of supplying the plasma chemical species to the substrate without supplying the first processing gas to the substrate; and (b) a step of supplying a second processing gas containing a second borazine compound containing an alkyl group to the substrate without supplying the plasma chemical species to the substrate; and (c) a step of repeating a cycle including (a) and (b) to perform a film forming process for forming a boron nitride film.

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