Film deposition method and film deposition apparatus

Abstract

This invention provides a technology to suppress nitriding of the substrate surface during the formation of a boron nitride film on the substrate. [Solution] The disclosed film formation method includes (a) performing a first sequence to form a first boron nitride film on a substrate, and (b) performing a second sequence after (a) to form a second boron nitride film on the first boron nitride film. The first sequence includes (a1) supplying a source gas containing a borazine compound to a substrate in a chamber, and (a2) supplying a first plasma chemical species generated from a nitrogen-free gas to the substrate for forming a first boron nitride film from the borazine compound. The second sequence includes (b1) supplying a source gas to a substrate in a chamber, and (b2) supplying a second plasma chemical species generated from a nitrogen-containing gas to a borazine compound on the first boron nitride film.

Description

Technical Field

[0004] , , , , ,

[0005] ,

[0001] Exemplary embodiments of the present disclosure relate to a method and an apparatus for forming a boron nitride film.

Background Art

[0002] The following Patent Documents 1 to 3 disclose a method of forming a hexagonal boron nitride film on the surface of a substrate by supplying plasma species of a boron-containing gas and a nitrogen-containing gas to the substrate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

[0006] According to one exemplary embodiment, it is possible to suppress nitriding of the substrate surface during the formation of a boron nitride film on the substrate. [Brief explanation of the drawing]

[0007] [Figure 1] This is a timing chart illustrating a method for depositing a boron nitride film according to one exemplary embodiment. [Figure 2] Figure 2(a) is a partially enlarged cross-sectional view of an example substrate, Figure 2(b) is a partially enlarged cross-sectional view of an example substrate having a first boron nitride film, and Figure 2(c) is a partially enlarged cross-sectional view of an example substrate having first and second boron nitride films. [Figure 3] This figure shows the configuration of a film deposition apparatus according to one exemplary embodiment. [Figure 4] This is a graph showing the results of the experiment. [Modes for carrying out the invention]

[0008] Various exemplary embodiments will be described in detail below with reference to the drawings. In each drawing, the same or corresponding parts will be denoted by the same reference numerals.

[0009] <Method for forming boron nitride films>

[0010] First, a method for depositing a boron nitride film according to one exemplary embodiment will be described with reference to Figures 1 and 2(a) to 2(c). Figure 1 is a timing chart showing a method for depositing a boron nitride film according to one exemplary embodiment. In Figure 1, the states in which various gases are supplied and the states in which high-frequency (RF) power is supplied are shown by solid lines with arrows. Figure 2(a) is a partially enlarged cross-sectional view of an example substrate, Figure 2(b) is a partially enlarged cross-sectional view of an example substrate having a first boron nitride film, and Figure 2(c) is a partially enlarged cross-sectional view of an example substrate having first and second boron nitride films.

[0011] Method MT is performed using a film deposition apparatus such as the film deposition apparatus 100 described later. Method MT is performed to form a boron nitride film on a substrate W, i.e., a base substrate UR, as shown in Figure 2(a). The base substrate UR in the state shown in Figure 2(a) may be a semiconductor substrate or may be formed from silicon.

[0012] As shown in Figure 1, method MT includes steps STa and STb. Method MT may further include step STc, which is performed between steps STa and STb.

[0013] In step STa, the first sequence SQ1 is executed to form a first boron nitride film F1 on the substrate UR, as shown in Figure 2(b). In step STa, the first sequence SQ1 is executed x times, where x is an integer of 1 or more. In step STa, the first sequence SQ1 is executed once or repeated to form a first boron nitride film F1 having the required thickness. In one embodiment, the thickness of the first boron nitride film F1 may be 8 nm or less. In one embodiment, the thickness of the first boron nitride film F1 may be 1 nm or more, or 2 nm or more.

[0014] As shown in FIG. 1, the first sequence SQ1 includes step ST11 and step ST12. The first sequence SQ1 may further include step ST1p that is executed after step ST12. The first sequence SQ1 may further include step ST1f that is executed before step ST11.

[0015] In step ST1f, preparations for step ST11 are made. In step ST1f, a nitrogen-free gas and a purge gas, which will be described later, are supplied into the chamber of the film forming apparatus. Note that the purge gas may be continuously supplied into the chamber during step STa. In step ST1f, a raw material gas, which will be described later, may be further supplied into the chamber. In step ST1f, RF (radio frequency) power for generating plasma is not supplied.

[0016] In step ST11, a raw material gas containing a borazine compound is supplied to the substrate W (i.e., the underlying substrate UR) in the chamber of the film forming apparatus. In step ST11, the borazine compound in the raw material gas adsorbs on the surface of the underlying substrate UR.

[0017] The borazine compound is a compound having a borazine ring in which three B (boron atoms) and three N (nitrogen atoms) are alternately bonded as a basic skeleton.

[0018] The borazine compound may be borazine represented by the following formula (1), that is, cyclotriborazane (B3H6N3).

Chemical formula

[0019] The borazine compound may be an organic borazine compound in which some or all of the H of borazine is substituted with an organic ligand. The organic borazine compound may be an alkyl borazine compound containing an alkyl group as an organic ligand. The alkyl borazine compound may be N,N’,N’’-trimethylborazine (TMB) having the structure represented by the following formula (2).

Chemical formula

[0020] The alkylborazine compound may contain TMB, N,N',N''-triethylborazine, N,N',N''-tripropylborazine, N,N',N''-triisopropylborazine, B,B',B''-trimethylborazine, or B,B',B''-triethyl-N,N',N''-trimethylborazine, or one or more of these.

[0021] In the subsequent step ST12, a first plasma chemical species is supplied to the substrate W after step ST11 in the chamber of the film deposition apparatus. The first plasma chemical species is generated from a nitrogen-free gas. The nitrogen-free gas is, for example, hydrogen gas (H2 gas). The nitrogen-free gas may also be other gases, such as a noble gas (e.g., argon gas), as long as it does not contain nitrogen and can form a first boron nitride film F1 from the borazine compound film.

[0022] The plasma species used in the first plasma species method MT can be supplied to the substrate W inside the chamber from plasma generated inside or outside the chamber. The plasma may be an RF plasma obtained by exciting a gas using RF (radio frequency) power. Examples of RF plasmas include capacitively coupled plasma (CCP), inductively coupled plasma (ICP), helicon wave plasma, and electron cyclotron resonance (ECR) plasma.

[0023] In step ST12, nitrogen-free gas is supplied into the chamber of the film deposition apparatus, and RF power is supplied to generate plasma from the nitrogen-free gas. In step ST12, a first plasma chemical species (e.g., hydrogen plasma chemical species) from the plasma is supplied to the borazine compound film, and a first boron nitride film F1 is formed on the substrate UR (see Figure 2(b)).

[0024] As shown in Figure 1, the supply of nitrogen-free gas and RF power may be carried out from process ST11 to process ST12. Also, in process ST12, the raw material gas does not have to be supplied into the chamber. That is, in process ST12, the raw material gas does not have to be supplied to the substrate W in the chamber.

[0025] In the subsequent step ST1p, the chamber of the film deposition apparatus is purged. In step ST1p, a purge gas may be supplied into the chamber of the film deposition apparatus. The purge gas may be an inert gas. The inert gas may be a noble gas such as argon gas.

[0026] Following step STa, step STb is executed. In step STb, the second sequence SQ2 is executed to form a second boron nitride film F2 on the first boron nitride film F1 on the substrate W, as shown in Figure 2(c). In step STb, the second sequence SQ2 is executed y times, where y is an integer greater than or equal to 1. In step STb, the second sequence SQ2 is executed once or repeatedly to form a second boron nitride film F2 having the required thickness.

[0027] As shown in Figure 1, the second sequence SQ2 includes steps ST21 and ST22. The second sequence SQ2 may further include step ST2p1, which is executed after step ST22. The second sequence SQ2 may further include step ST23, which is executed after either step ST22 or step ST2p1. The second sequence SQ2 may further include step ST2p2, which is executed after step ST23. The second sequence SQ2 may also further include step ST2f, which is executed before step ST21.

[0028] In step ST2f, preparations for step ST21 are carried out. In step ST2f, a nitrogen-containing gas and a purge gas, described later, are supplied into the chamber of the film deposition apparatus. Note that the purge gas may be continuously supplied into the chamber during step STb. In step ST2f, a source gas, described later, may be further supplied into the chamber. RF power for generating plasma is not supplied in step ST2f.

[0029] In step ST21, a raw material gas containing a borazine compound is supplied to the substrate W in the chamber of the film deposition apparatus. The borazine compound in the raw material gas used in step ST21 may be any of the above-mentioned examples of the borazine compound in the raw material gas used in step ST11. The raw material gas used in step ST21 may be the same as or different from the raw material gas used in step ST11. That is, the borazine compound in the raw material gas used in step ST21 may be the same as or different from the borazine compound in the raw material gas used in step ST11. In step ST21, the borazine compound in the raw material gas is adsorbed onto the surface of the first boron nitride film F1.

[0030] In the subsequent step ST22, a second plasma chemical species is supplied to the substrate W after step ST21, i.e., the borazine compound on the first boron nitride film F1, within the chamber of the film deposition apparatus. The second plasma chemical species is generated from a nitrogen-containing gas. In one embodiment, the nitrogen-containing gas may contain ammonia gas (NH3 gas). In another embodiment, the nitrogen-containing gas may contain nitrogen gas (N2 gas).

[0031] In step ST22, nitrogen-containing gas is supplied into the chamber of the film deposition apparatus, and RF power is supplied to generate plasma from the nitrogen-containing gas. In step ST22, a second plasma chemical species (e.g., nitrogen-containing plasma chemical species) from the plasma is supplied to the borazine compound film, and a second boron nitride film F2 is formed on the first boron nitride film F1 (see Figure 2(c)).

[0032] As shown in Figure 1, the supply of nitrogen-containing gas and RF power may be carried out from process ST21 to process ST22. Also, in process ST22, the raw material gas does not have to be supplied into the chamber. That is, in process ST22, the raw material gas does not have to be supplied to the substrate W in the chamber.

[0033] The second boron nitride film F2 may be a hexagonal boron nitride (h-BN) film. In this case, the temperature of the substrate W in steps ST21 and ST22 may be 200°C or higher and 400°C or lower. The pressure inside the chamber in steps ST21 and ST22 may be 4 Torr or higher. The pressure inside the chamber in steps ST21 and ST22 may also be less than 12 Torr. When the pressure inside the chamber in steps ST21 and ST22 is less than 12 Torr, a high film deposition rate (GPC: Growth per Cycle) can be obtained. The time for step ST21 may also be 2 seconds or less. When the time for step ST21 is 2 seconds or less, it is possible to significantly suppress the amorphous component in the second boron nitride film F2. The time for step ST22 may also be 4 seconds or more. When the time for step ST22 is 4 seconds or more, the formation of lateral orientation of h-BN is promoted. Furthermore, the RF power level in steps ST21 and ST22 may be 100W or higher. When the RF power level in steps ST21 and ST22 is 100W or higher, it becomes possible to form a second boron nitride film F2 having high film quality.

[0034] In the subsequent step ST2p1, the chamber of the film deposition apparatus is purged. In step ST2p1, a purge gas may be supplied into the chamber of the film deposition apparatus. The purge gas may be an inert gas. The inert gas may be a noble gas such as argon gas.

[0035] In the subsequent step ST23, nitrogen plasma chemical species generated from nitrogen gas (N2 gas) are supplied to the substrate in the chamber of the film deposition apparatus. In step ST23, nitrogen gas is supplied to the chamber of the film deposition apparatus, and RF power is supplied to generate plasma from the nitrogen gas. In step ST23, nitrogen plasma chemical species from the plasma are supplied to the second boron nitride film F2, and the second boron nitride film F2 is modified.

[0036] In step ST23, the processing temperature of the substrate W may be 200°C or higher and 400°C or lower, similar to the processing temperature of the substrate W in steps ST21 and ST22. The pressure inside the chamber in step ST23 may be 6 Torr or higher. The duration of step ST23 may be 1 second or longer. The RF power level in step ST23 may be 400W or higher.

[0037] In the subsequent step ST2p2, the chamber of the film deposition apparatus is purged. In step ST2p2, a purge gas may be supplied into the chamber of the film deposition apparatus. The purge gas may be an inert gas. The inert gas may be a noble gas such as argon gas.

[0038] As described above, step STc may be performed between steps STa and STb. In step STc, a third plasma chemical species generated from nitrogen gas (N2 gas) and / or a noble gas such as argon gas is supplied to the first boron nitride film F1. In step STc, nitrogen gas and / or a noble gas is supplied into the chamber of the deposition apparatus, and RF power is supplied to generate plasma from the nitrogen gas and / or noble gas. In step STc, the third plasma chemical species from the plasma is supplied to the first boron nitride film F1, thereby modifying the first boron nitride film F1.

[0039] As explained above, in method MT, the first boron nitride film F1 is formed on the substrate UR using plasma generated from a nitrogen-free gas before the second boron nitride film F2 is formed. Therefore, in method MT, nitriding of the substrate UR is suppressed.

[0040] Furthermore, as mentioned above, the thickness of the first boron nitride film F1 may be 1 nm or more, or 2 nm or more. In this case, nitriding of the underlying substrate UR is more reliably suppressed. Also, as mentioned above, the thickness of the first boron nitride film F1 may be 8 nm or less. In this case, it is possible to obtain a second boron nitride film F2 with high orientation.

[0041] Furthermore, if method MT includes step STc, it is possible to reduce the variation in the orientation angle of the second boron nitride film F2 and to increase the crystal size (orientation distance) of the second boron nitride film F2.

[0042] <Film forming equipment>

[0043] The following describes a film deposition apparatus according to one exemplary embodiment, with reference to Figure 3. Figure 3 is a diagram showing the configuration of a film deposition apparatus according to one exemplary embodiment. The film deposition apparatus 100 shown in Figure 3 is a film deposition apparatus that can be used in method MT. The film deposition apparatus 100 includes a chamber 1, a gas supply mechanism 5, a plasma generation unit 6, and a control unit 7. The film deposition apparatus 100 may further include a mounting table 2, a shower head 3, and an exhaust unit 4.

[0044] Chamber 1 is capable of housing a substrate W within its internal space. Chamber 1 is made of a metal such as aluminum and has a substantially cylindrical shape. An inlet / outlet 11 for loading and unloading the substrate W is formed in the side wall of Chamber 1, and the inlet / outlet 11 can be opened and closed by a gate valve 12. An annular exhaust duct 13 with a rectangular cross-section is provided on top of the main body of Chamber 1.

[0045] A slit 13a is formed along the inner circumference of the exhaust duct 13. An exhaust port 13b is also formed on the outer wall of the exhaust duct 13. A top wall 14 is provided on the upper surface of the exhaust duct 13 to close the upper opening of the chamber 1. A sealing ring 15 is sandwiched between the top wall 14 and the exhaust duct 13 to ensure airtightness of the space inside the chamber 10.

[0046] The mounting base 2 is a base capable of supporting the substrate W placed on it in a horizontal position. It is a disc-shaped base sized to correspond to the substrate W and is supported by a support member 23. This mounting base 2 is made of a ceramic material such as aluminum nitride (AlN) or a metallic material such as aluminum or nickel-based alloy. A heater 21 for heating the substrate W is embedded inside the mounting base 2. A cover member 22 is provided on the mounting base 2 to cover its sides.

[0047] The support member 23 that supports the mounting table 2 extends downward from the center of the bottom surface of the mounting table 2, through a hole formed in the bottom wall of the chamber 1, and downward from the chamber 1. The lower end of the support member 23 is connected to the mounting table lifting mechanism 24. The mounting table 2 can be raised and lowered between the processing position shown by the solid line and the transport position shown by the dashed line, via the support member 23 and the mounting table lifting mechanism 24. The transport position is lower than the processing position and is the position where the substrate is placed for transport.

[0048] Below the chamber 1, a flange portion 25 is attached to the support member 23. Between the bottom surface of the chamber 1 and the flange portion 25, a bellows 26 is provided that partitions the atmosphere inside the chamber 1 from the outside air and expands and contracts in accordance with the raising and lowering movement of the mounting platform 2.

[0049] Near the bottom of the chamber 1, three substrate support pins 27 (only two are shown) are provided, protruding upward from the lifting plate 27a. The substrate support pins 27 can be raised and lowered via the lifting plate 27a by a substrate support pin lifting mechanism 28 provided below the chamber 1, and can be inserted through holes 2a provided in the mounting table 2 at the transport position, allowing them to protrude and retract relative to the upper surface of the mounting table 2.

[0050] By raising and lowering the substrate support pins 27 in this manner, the substrate W is transferred between the 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.

[0051] The shower head 3 supplies the processed gas into the chamber 1 in a shower-like manner. The shower head 3 is positioned opposite the mounting base 2 and has approximately the same diameter as the mounting base 2. The shower head 3 has a shower body 31 fixed to the top wall 14 of the chamber 1 and a shower plate 32 connected below the shower body 31.

[0052] A gas diffusion space 33 is formed between the shower body 31 and the shower plate 32. A gas inlet 36, which is provided to penetrate the shower body 31 and the center of the top wall 14 of the chamber 1, is connected to this gas diffusion space 33. A gas discharge hole 34 is formed in the shower plate 32. The gas discharge hole 34 extends downward from the gas diffusion space 33 and penetrates the shower plate 32. When the mounting base 2 is in the processing position, a processing space S is formed between the shower plate 32 and the mounting base 2.

[0053] 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, the gas in 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.

[0054] The gas supply mechanism 5 supplies the gas used for film formation to the shower head 3. That is, the gas supply mechanism 5 can supply the above-mentioned raw material gas, nitrogen-free gas, nitrogen-containing gas, nitrogen gas, and purge gas to the processing space S in the chamber 1 via the shower head 3.

[0055] The gas supply mechanism 5 includes a raw material gas supply source 51, a nitrogen-free gas supply source 52, a nitrogen-containing gas supply source 53, a nitrogen gas supply source 54, and a purge gas supply source 55. Supply source 51 is connected to the gas inlet 36 via a flow regulator 51d, a fill tank 51c, and a valve 51b. Supply source 52 is connected to the gas inlet 36 via a flow regulator 52d, a fill tank 52c, and a valve 52b. Supply source 53 is connected to the gas inlet 36 via a flow regulator 53d, a fill tank 53c, and a valve 53b. Supply source 54 is connected to the gas inlet 36 via a flow regulator 54d, a fill tank 54c, and a valve 54b. In addition, supply source 55 is connected to the gas inlet 36 via a flow regulator 55d and a valve 55b.

[0056] Valves 51b, 52b, 53b, and 54b may be configured as high-speed on / off valves that can be opened and closed at high speed. Valve 55b may be a normal on / off valve. During the execution of method MT, valve 55b may be kept open at all times, and purge gas may be continuously supplied into chamber 1.

[0057] Fill tanks 51c, 52c, 53c, and 54c are tanks for temporarily storing the raw material gas, nitrogen-free gas, nitrogen-containing gas, and nitrogen gas, respectively, before supplying them into chamber 1.

[0058] By storing the corresponding gas in fill tanks 51c, 52c, 53c, and 54c, a state can be created where the pressure inside each tank is increased to a predetermined pressure. After increasing the pressure inside each of fill tanks 51c, 52c, 53c, and 54c, the corresponding gas can be discharged into chamber 1 by opening the corresponding valve among valves 51b, 52b, 53b, and 54b. This makes it possible to stably supply a large flow rate of gas to chamber 1.

[0059] Flow regulators 51d, 52d, 53d, 54d, and 55d are configured, for example, by a mass flow controller. Each of the flow regulators 51d, 52d, 53d, 54d, and 55d is configured to adjust the flow rate of the gas flowing in from upstream and to output the gas with the adjusted flow rate.

[0060] The plasma generation unit 6 includes a power supply line 61 connected to the shower body 31 of the shower head 3, a matching unit 62 and an RF power supply 63 (high-frequency power supply) connected to the power supply line 61. When high-frequency (RF) power is supplied to the shower head 3 from the RF power supply 63, a high-frequency (RF) electric field is formed in the processing space S between the shower head 3 and the mounting base 2, and plasma is generated from the gas as a capacitively coupled plasma by this RF electric field. If the mounting base 2 is made of ceramic material, the RF electric field may be formed between the shower head 3 and electrodes embedded in the mounting base 2.

[0061] The control unit 7 is composed of a computer and includes a main control unit equipped with a CPU, an input device, an output device, a display device, and a storage device (storage medium). The main control unit controls the components of the film deposition apparatus 100, such as valves, flow regulators, automatic pressure control valves, heaters, and lifting mechanisms.

[0062] The memory device stores parameters for various processes performed by the film deposition apparatus 100. The memory device also has a storage medium that stores programs, i.e., processing recipes, for controlling the processes performed by the film deposition apparatus 100. The main control unit retrieves a predetermined processing recipe stored in the storage medium and, based on that processing recipe, causes the film deposition apparatus 100 to perform a predetermined operation.

[0063] The control unit 7 is configured to execute method MT by controlling each part of the film deposition apparatus 100, such as the gas supply mechanism 5 and the plasma generation unit 6, while the substrate W is housed in the chamber 1.

[0064] An example of method MT using the film deposition apparatus 100 described above is described below. In this example, first, the substrate W, i.e., the base substrate UR (see Figure 2(a)), is prepared in the chamber 1 of the film deposition apparatus 100. Specifically, the gate valve 12 is opened and the substrate W is loaded into the chamber 1. The substrate W is loaded via the loading port 11 by a transport device (not shown). The loaded substrate W is placed on the mounting table 2. Next, the transport device is moved out of the space inside the chamber 1 and the mounting table 2 is raised to the processing position. Then, the gate valve 12 is closed and the chamber 1 is evacuated. After that, the mounting table 2 is heated by the heater 21 and the temperature of the mounting table 2 (substrate temperature) is adjusted to the desired temperature.

[0065] With the substrate W prepared in the chamber 1 of the deposition apparatus 100 in this manner, the deposition process of method MT can be started. Below, an example of the deposition process when using method MT will be described as shown in Figure 1.

[0066] First, in process ST1f, valves 55b and 52b are set to the open state, and purge gas and nitrogen-free gas are supplied from supply sources 55 and 52 to the processing space S via the showerhead 3. The purge gas may be continuously supplied to the processing space S throughout process STa. Also, in process ST1f, valve 51b may be set to the open state, and raw material gas may be further supplied from supply source 51 to the processing space S via the showerhead 3.

[0067] In step ST11, the valve 51b is set to the open state and raw material gas is supplied from the supply source 51 to the processing space S via the shower head 3. In step ST11, the valve 52b may also be set to the open state and nitrogen-free gas may be further supplied from the supply source 52 to the processing space S via the shower head 3. In step ST11, RF power may also be supplied from the RF power supply 63 of the plasma generation unit 6 to the shower head 3 to generate plasma from the gas in the processing space S. In step ST11, as described above, raw material gas is supplied to the substrate UR and the borazine compound in the raw material gas is adsorbed onto the surface of the substrate UR.

[0068] In step ST12, the valve 52b is set to the open state, and nitrogen-free gas is further supplied from the supply source 52 to the processing space S via the shower head 3. Also in step ST12, RF power is supplied from the RF power supply 63 of the plasma generation unit 6 to the shower head 3, and plasma is generated from the gas in the processing space S. In step ST12, the valve 51b may be set to the closed state. In step ST12, a first plasma chemical species is supplied from the plasma to the borazine compound, and a first boron nitride film F1 is formed on the substrate UR.

[0069] In step ST1p, chamber 1 is purged. In step ST1p, the valve 55b is set to the open state, and purge gas is supplied from the supply source 55 to the processing space S via the shower head 3. The gas in chamber 1 is exhausted by the exhaust unit 4. Also in step ST1p, the supply of RF power from the RF power supply 63 is stopped.

[0070] In step STc, the valve 54b is set to the open state, and nitrogen gas is supplied to the processing space S via the showerhead 3. In step STc, the valve 55b may also be set to the open state, and purge gas may be further supplied to the processing space S via the showerhead 3. In step STc, RF power is supplied from the RF power supply 63 of the plasma generation unit 6 to the showerhead 3, and plasma is generated from the gas in the processing space S. In step STc, as described above, nitrogen plasma chemical species are supplied from the plasma to the first boron nitride film F1, and the first boron nitride film F1 is modified.

[0071] In step ST2f, valves 55b and 53b are set to the open state, and purge gas and nitrogen-containing gas are supplied from supply sources 55 and 53 to the processing space S via the showerhead 3. The purge gas may be continuously supplied to the processing space S throughout step STb, as described above. In step ST2f, valve 51b may be set to the open state, and raw material gas may be further supplied from supply source 51 to the processing space S via the showerhead 3.

[0072] In step ST21, the valve 51b is set to the open state and raw material gas is supplied from the supply source 51 to the processing space S via the shower head 3. In step ST21, the valve 53b may also be set to the open state and nitrogen-containing gas may be further supplied from the supply source 53 to the processing space S via the shower head 3. In step ST21, RF power may also be supplied from the RF power supply 63 of the plasma generation unit 6 to the shower head 3 to generate plasma from the gas in the processing space S. In step ST21, as described above, raw material gas is supplied to the substrate W and the borazine compound in the raw material gas is adsorbed onto the surface of the first boron nitride film F1.

[0073] In step ST22, the valve 53b is set to the open state, and nitrogen-containing gas is further supplied from the supply source 53 to the processing space S via the shower head 3. Also in step ST22, RF power is supplied from the RF power supply 63 of the plasma generation unit 6 to the shower head 3, and plasma is generated from the gas in the processing space S. In step ST22, the valve 51b may be set to the closed state. In step ST22, a second plasma chemical species is supplied from the plasma to the borazine compound, and a second boron nitride film F2 is formed on the first boron nitride film F1.

[0074] In step ST2p1, the chamber 1 is purged. In step ST2p1, the valve 55b is set to the open state, and purge gas is supplied from the supply source 55 to the processing space S via the shower head 3. The gas in the chamber 1 is exhausted by the exhaust unit 4. Also in step ST2p1, the supply of RF power from the RF power supply 63 is stopped.

[0075] In step ST23, the valve 54b is set to the open state, and nitrogen gas is supplied to the processing space S via the showerhead 3. In step ST23, the valve 55b may also be set to the open state, and purge gas may be further supplied to the processing space S via the showerhead 3. In step ST23, RF power is supplied from the RF power supply 63 of the plasma generation unit 6 to the showerhead 3, and plasma is generated from the gas in the processing space S. In step ST23, as described above, nitrogen plasma chemical species are supplied from the plasma to the second boron nitride film F2, and the second boron nitride film F2 is modified.

[0076] In step ST2p2, chamber 1 is purged. In step ST2p2, the valve 55b is set to the open state, and purge gas is supplied from the supply source 55 to the processing space S via the shower head 3. The gas in chamber 1 is exhausted by the exhaust unit 4. Also in step ST2p2, the supply of RF power from the RF power supply 63 is stopped.

[0077] <Evaluation experiment>

[0078] The following describes the evaluation experiment (hereinafter referred to as "the experiment") conducted to evaluate method MT. In the experiment, method MT was performed using the film deposition apparatus 100 to sequentially form a first boron nitride film F1 and a second boron nitride film F2 on silicon substrates of multiple sample substrates. In the experiment, hydrogen gas was used as the nitrogen-free gas and ammonia gas was used as the nitrogen-containing gas. In the experiment, various processing conditions were set to form a hexagonal boron nitride film as the second boron nitride film F2. In addition, in the experiment, the thickness of the first boron nitride film F1 formed on the substrates of multiple sample substrates was set to a different thickness from one another. The film deposition conditions for the first boron nitride film F1 for each of the multiple sample substrates were the same from one another, except for the number of times the first sequence Q1 was executed. The film deposition conditions for the second boron nitride film F2 for each of the multiple sample substrates were also the same from one another.

[0079] In the experiment, the arithmetic mean roughness Sa, as defined in ISO 25178, was determined for each surface of the first boron nitride film F1 on multiple sample substrates. Note that a smaller arithmetic mean roughness Sa tends to indicate higher orientation of the second boron nitride film F2. Figure 4 shows the experimental results. In the graph in Figure 4, the horizontal axis represents the thickness of the first boron nitride film F1, and the vertical axis represents the arithmetic mean roughness Sa of the surface of the first boron nitride film F1. As can be seen from Figure 4, the experimental results confirmed that an arithmetic mean roughness Sa of 0.5 nm or less can be obtained if the thickness of the first boron nitride film F1 is 8 nm or less.

[0080] Although various exemplary embodiments have been described above, the invention is not limited to the exemplary embodiments described above, and various additions, omissions, substitutions, and modifications may be made. Furthermore, it is possible to combine elements from different embodiments to form other embodiments.

[0081] Herein, various exemplary embodiments included in this disclosure are described in [E1] to [E16] below.

[0082] [E1] (a) A step of performing a first sequence to form a first boron nitride film on a substrate, (b) After (a), a step of performing a second sequence to form a second boron nitride film on the first boron nitride film, Includes, The first sequence described above is: (a1) A step of supplying a raw material gas containing a borazine compound to the substrate in the chamber, (a2) A step of supplying a first plasma chemical species generated from a nitrogen-free gas to the substrate for forming the first boron nitride film from the borazine compound, Includes, The second sequence is, (b1) A step of supplying the raw material gas to the substrate in the chamber, (b2) A step of supplying a second plasma chemical species generated from a nitrogen-containing gas to the borazine compound on the first boron nitride film, including, Film formation method.

[0083] [E2] The film deposition method according to E1, wherein the first plasma chemical species is a hydrogen plasma chemical species generated from the hydrogen gas, which is the nitrogen-free gas.

[0084] [E3] (c) The film formation method according to E2, further comprising the step of supplying a third plasma chemical species generated from nitrogen gas and / or a noble gas to the first boron nitride film between (a) and (b).

[0085] [E4] The film deposition method according to any one of E1 to E3, wherein the thickness of the first boron nitride film is 8 nm or less.

[0086] [E5] The film formation method according to any one of E1 to E4, wherein the thickness of the first boron nitride film is 1 nm or more or 2 nm or more.

[0087] [E6] (b1) above includes supplying the second plasma chemical species to the substrate together with the raw material gas, In (b2) above, the source gas is not supplied to the substrate. A film formation method described in any one of items E1 to E5.

[0088] [E7] The second plasma chemical species is generated from the nitrogen-containing gas containing ammonia gas, according to the film deposition method described in any one of E1 to E6.

[0089] [E8] The second sequence is, (b3) After (b2), a step of supplying nitrogen plasma chemical species generated from nitrogen gas to the substrate is performed. Furthermore, the film formation method described in E7.

[0090] [E9] (a1) above includes supplying the first plasma chemical species to the substrate together with the raw material gas, In (a2) above, the source gas is not supplied to the substrate. A film deposition method described in any one of items E1 to E8.

[0091] [E10] A film deposition method according to any one of E1 to E9, wherein, after the first sequence in (a) is executed once or more times, the second sequence in (b) is executed multiple times.

[0092] [E11] The method for forming a film according to any one of E1 to E10, wherein the borazine compound is an alkylborazine compound.

[0093] [E12] The method for forming a film according to E11, wherein the borazine compound is trimethylborazine.

[0094] [E13] The aforementioned substrate is a silicon substrate, and the film deposition method is as described in any one of E1 to E12.

[0095] [E14] Chamber and, A gas supply mechanism connected to the chamber, A plasma generation unit configured to generate plasma from gas within the chamber, Control unit and Equipped with, The control unit controls the gas supply mechanism and the plasma generation unit while the substrate is housed in the chamber. (a) A step of performing a first sequence to form a first boron nitride film on a substrate, (b) After (a), a step of performing a second sequence to form a second boron nitride film on the first boron nitride film, It is configured to perform a film deposition process that includes, The first sequence described above is: (a1) A step of supplying a raw material gas containing a borazine compound to the substrate in the chamber, (a2) A step of supplying a first plasma chemical species generated from a nitrogen-free gas to the substrate for forming the first boron nitride film from the borazine compound, Includes, The second sequence is, (b1) A step of supplying the raw material gas to the substrate in the chamber, (b2) A step of supplying a second plasma chemical species generated from a nitrogen-containing gas to the borazine compound on the first boron nitride film, including, Film deposition equipment.

[0096] [E15] The film deposition apparatus according to E14, wherein the control unit is configured to control the gas supply mechanism and the plasma generation unit to generate hydrogen plasma chemical species from hydrogen gas, which is a nitrogen-free gas, and to supply the hydrogen plasma chemical species as the first plasma chemical species to the substrate.

[0097] [E16] The film deposition apparatus according to E15, wherein the control unit is configured to control the gas supply mechanism and the plasma generation unit to supply a third plasma chemical species generated from nitrogen gas and / or a noble gas to the first boron nitride film between (a) and (b).

[0098] From the above description, it will be understood that the various embodiments of this disclosure are described herein for illustrative purposes and can be modified in various ways without departing from the scope and spirit of this disclosure. Accordingly, the various embodiments disclosed herein are not intended to limit the scope and spirit, and the true scope and spirit are shown by the appended claims. [Explanation of Symbols]

[0099] 100...Film deposition apparatus, 1...Chamber, 5...Gas supply mechanism, 6...Plasma generation unit, 7...Control unit, W...Substrate, UR...Underlayment substrate, F1...First boron nitride film, F2...Second boron nitride film.

Claims

1. (a) A step of performing a first sequence to form a first boron nitride film on a substrate, (b) After (a), a step of performing a second sequence to form a second boron nitride film on the first boron nitride film, Includes, The first sequence is, (a1) A step of supplying a raw material gas containing a borazine compound to the substrate in the chamber, (a2) A step of supplying a first plasma chemical species generated from a nitrogen-free gas to the substrate for forming the first boron nitride film from the borazine compound, Includes, The second sequence is, (b1) A step of supplying the raw material gas to the substrate in the chamber, (b2) A step of supplying a second plasma chemical species generated from a nitrogen-containing gas to the borazine compound on the first boron nitride film, including, Film formation method.

2. The method for forming a film according to claim 1, wherein the first plasma chemical species is a hydrogen plasma chemical species generated from the hydrogen gas, which is the nitrogen-free gas.

3. (c) The method for forming a film according to claim 2, further comprising the step of supplying a third plasma chemical species generated from nitrogen gas and / or a noble gas to the first boron nitride film between (a) and (b).

4. The method for forming a film according to any one of claims 1 to 3, wherein the thickness of the first boron nitride film is 8 nm or less.

5. The method for forming a film according to claim 4, wherein the thickness of the first boron nitride film is 1 nm or more or 2 nm or more.

6. (b1) includes supplying the second plasma chemical species to the substrate together with the raw material gas, In (b2) above, the source gas is not supplied to the substrate. A method for forming a film according to any one of claims 1 to 3.

7. The method for forming a film according to any one of claims 1 to 3, wherein the second plasma chemical species is generated from the nitrogen-containing gas containing ammonia gas.

8. The second sequence is, (b3) After (b2), a step is taken to supply nitrogen plasma chemical species generated from nitrogen gas to the substrate, The film formation method according to claim 7 is further included.

9. (a1) above includes supplying the first plasma chemical species to the substrate together with the raw material gas, In (a2) above, the source gas is not supplied to the substrate. A method for forming a film according to any one of claims 1 to 3.

10. The film formation method according to any one of claims 1 to 3, wherein, after the first sequence in (a) is executed once or more times, the second sequence in (b) is executed multiple times.

11. The method for forming a film according to any one of claims 1 to 3, wherein the borazine compound is an alkylborazine compound.

12. The method for forming a film according to claim 11, wherein the borazine compound is trimethylborazine.

13. The film formation method according to any one of claims 1 to 3, wherein the substrate is a silicon substrate.

14. Chamber and, A gas supply mechanism connected to the chamber, A plasma generation unit configured to generate plasma from gas within the chamber, Control unit and Equipped with, The control unit controls the gas supply mechanism and the plasma generation unit while the substrate is housed in the chamber. (a) A step of performing a first sequence to form a first boron nitride film on a substrate, (b) After (a), a step of performing a second sequence to form a second boron nitride film on the first boron nitride film, It is configured to perform a film deposition process that includes, The first sequence is, (a1) A step of supplying a raw material gas containing a borazine compound to the substrate in the chamber, (a2) A step of supplying a first plasma chemical species generated from a nitrogen-free gas to the substrate for forming the first boron nitride film from the borazine compound, Includes, The second sequence is, (b1) A step of supplying the raw material gas to the substrate in the chamber, (b2) A step of supplying a second plasma chemical species generated from a nitrogen-containing gas to the borazine compound on the first boron nitride film, including, Film deposition equipment.

15. The film deposition apparatus according to claim 14, wherein the control unit is configured to control the gas supply mechanism and the plasma generation unit to generate hydrogen plasma chemical species from hydrogen gas, which is a nitrogen-free gas, and to supply the hydrogen plasma chemical species as the first plasma chemical species to the substrate.

16. The film deposition apparatus according to claim 15, wherein the control unit is configured to control the gas supply mechanism and the plasma generation unit to supply a third plasma chemical species generated from nitrogen gas and / or a noble gas to the first boron nitride film between (a) and (b).

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