Deposition method and deposition apparatus

Abstract

To provide a technique that can suppress an increase in the resistance of a metal film and improve productivity during the deposition of a film containing silicon atoms and nitrogen atoms on the metal film.SOLUTION: A deposition method according to one aspect of the present disclosure for forming a film containing silicon atoms and nitrogen atoms on the surface of a substrate having a metal film on the surface includes steps of: supplying a boron-containing gas and a first nitride gas to the substrate to form a first film containing boron atoms and nitrogen atoms on the surface; and supplying a silicon-containing gas and a second nitride gas to the substrate to form a second film containing silicon atoms and nitrogen atoms on the first film.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a film forming method and a film forming apparatus. [Background technology]

[0002] A method for forming a silicon oxide film on a tungsten film by atomic layer deposition (ALD) using a silicon-containing gas and oxygen active species is known (see, for example, Patent Document 1). In Patent Document 1, a first silicon oxide film is formed by low-temperature film formation at 25 to 350°C, and then a second silicon oxide film is formed by medium- to high-temperature film formation at 500 to 750°C, thereby suppressing oxidation of the tungsten film. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-29582 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique that can achieve both suppression of an increase in resistivity of a metal film and improvement in productivity when forming a film containing silicon atoms and nitrogen atoms on a metal film. [Means for solving the problem]

[0005] A film formation method according to one embodiment of the present disclosure is a film formation method for forming a film containing silicon atoms and nitrogen atoms on a surface of a substrate having a metal film on the surface, the method comprising the steps of supplying a boron-containing gas and a first nitriding gas to the substrate to form a first film containing boron atoms and nitrogen atoms on the surface, and supplying a silicon-containing gas and a second nitriding gas to the substrate to form a second film containing silicon atoms and nitrogen atoms on the first film. Effect of the Invention

[0006] According to the present disclosure, when a film containing silicon atoms and nitrogen atoms is formed on a metal film, it is possible to suppress an increase in resistivity of the metal film and improve productivity at the same time. [Brief description of the drawings]

[0007] [Figure 1] 2 is a flowchart illustrating a film forming method according to an embodiment. [Diagram 2] 1A to 1C are cross-sectional views illustrating a film forming method according to an embodiment. [Diagram 3] 1 is a flowchart showing an example of a process for forming a BN film. [Figure 4] 13 is a flowchart showing another example of the process of forming a BN film. [Diagram 5] 1 is a vertical cross-sectional view showing a film forming apparatus according to an embodiment. [Figure 6] 1 is a horizontal cross-sectional view showing a film forming apparatus according to an embodiment. [Figure 7] FIG. 13 is a diagram showing the measurement results of the sheet resistance of a Ru film. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, non-limiting exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings. In all of the accompanying drawings, the same or corresponding members or parts are designated by the same or corresponding reference numerals, and duplicated descriptions will be omitted.

[0009] [Film formation method] A film forming method according to an embodiment will be described with reference to Figs. 1 and 2. Fig. 1 is a flowchart showing the film forming method according to the embodiment. Fig. 2 is a cross-sectional view showing the film forming method according to the embodiment. In the embodiment, a case where a boron nitride (BN) film and a silicon nitride (SiN) film are formed in this order on a ruthenium (Ru) film will be described as an example. The Ru film is an example of a metal film, the BN film is an example of a first film containing boron (B) atoms and nitrogen (N) atoms, and the SiN film is an example of a second film containing silicon (Si) atoms and nitrogen atoms.

[0010] In step S1, as shown in FIG. 2(a), a substrate 100 is prepared. The substrate 100 has an insulating film 101, a barrier metal film 102, and a Ru film 103. The insulating film 101 is, for example, a thermal oxide film. The barrier metal film 102 is provided on the insulating film 101. The barrier metal film 102 is, for example, a titanium nitride (TiN) film. The Ru film 103 is provided on the barrier metal film 102. The Ru film 103 is formed by, for example, a physical vapor deposition (PVD) method. The Ru film 103 may be heat-treated, for example, in a reduced pressure atmosphere or an inert gas atmosphere maintained at 600° C. or more and 700° C. or less. In this case, the crystal grain size of the Ru film 103 can be increased to reduce the resistivity.

[0011] Step S2 is performed after step S1. In step S2, while the temperature of the substrate 100 is maintained at a first temperature, as shown in FIG. 2(b), a BN film 104 is formed on the Ru film 103. The first temperature is, for example, 550° C. or more and 650° C. or less. The BN film 104 can be formed by, for example, a thermal ALD method in which a boron-containing gas is alternately supplied to the substrate 100 and a first nitriding gas is alternately supplied to the substrate 100. In this case, the BN film 104 is easily formed conformally along the surface of the Ru film 103. The boron-containing gas is a gas that contains boron atoms and does not contain silicon atoms. The boron-containing gas is, for example, diborane (B2H6) gas or boron trichloride (BCl3) gas. The first nitriding gas is, for example, ammonia (NH3) gas. The thickness of the BN film 104 is, for example, 1 nm or more. In this case, even if the Ru film 103 is exposed to a silicon-containing gas at the first temperature in step S3, the Ru film 103 is unlikely to be silicided.

[0012] Step S3 is performed after step S2. In step S3, while the temperature of the substrate 100 is maintained at the first temperature, as shown in FIG. 2(c), a SiN film 105 is formed on the BN film 104. The SiN film 105 can be formed by, for example, a plasma ALD method in which a silicon-containing gas is supplied to the substrate 100 and the substrate 100 is exposed to plasma generated from a second nitriding gas in an alternating manner. In this case, a high-quality SiN film 105 can be formed conformally along the surface of the BN film 104. The silicon-containing gas is, for example, dichlorosilane (DCS) gas. The second nitriding gas is, for example, the same gas as the first nitriding gas. The second nitriding gas is, for example, ammonia gas.

[0013] By carrying out the above steps S1 to S3, a laminated film 106 can be formed in which the BN film 104 and the SiN film 105 are laminated in this order on the Ru film 103.

[0014] Incidentally, when the SiN film 105 is formed on the Ru film 103 at a high temperature (for example, 550° C. or higher), silicon (Si) atoms contained in a silicon-containing gas diffuse into the Ru film 103, forming a ruthenium silicide (RuSi) layer in the Ru film 103. When the RuSi layer is formed in the Ru film 103, the resistance of the Ru film 103 becomes high.

[0015] In the film forming method according to the embodiment, the BN film 104 is formed on the Ru film 103, and the SiN film 105 is formed on the BN film 104. The boron-containing gas used in forming the BN film 104 does not contain silicon atoms. Therefore, even if the surface of the Ru film 103 is exposed when the BN film 104 is formed, the Ru film 103 is not silicided. Since the surface of the Ru film 103 is covered with the BN film 104 when the SiN film 105 is formed, the surface of the Ru film 103 is not exposed to the silicon-containing gas. Therefore, the silicide of the Ru film 103 can be suppressed. As a result, an increase in the resistivity of the Ru film 103 can be suppressed. Moreover, in the film forming method according to the embodiment, the BN film 104 can be formed at the same temperature as the temperature when the SiN film 105 is formed, so that the BN film 104 and the SiN film 105 can be formed continuously without changing the temperature. This improves productivity. As described above, according to the film formation method of the embodiment, when forming the SiN film 105 on the Ru film 103, it is possible to suppress an increase in the resistivity of the Ru film 103 and to improve the productivity at the same time.

[0016] An example of a method for forming the BN film 104 in step S2 will be described with reference to Fig. 3. Fig. 3 is a flow chart showing an example of a process for forming the BN film 104.

[0017] 3 is started, a purge gas is supplied in step S21. This causes the surface of the substrate 100 to be purged with the purge gas, and excess gas molecules attached to the surface of the substrate 100 are removed. The purge gas may be, for example, argon (Ar) gas, nitrogen (N2) gas, or a mixed gas of argon gas and nitrogen gas.

[0018] After a predetermined time has elapsed since the start of step S21, the supply of the purge gas is stopped, and in step S22, a boron-containing gas is supplied, whereby the boron-containing gas is adsorbed onto the substrate 100.

[0019] After a predetermined time has elapsed since the start of step S22, the supply of the boron-containing gas is stopped, and a purge gas is supplied in step S23, whereby the surface of the substrate 100 is purged with the purge gas, and excess gas molecules attached to the surface of the substrate 100 are removed.

[0020] After a predetermined time has elapsed since the start of step S23, the supply of the purge gas is stopped, and in step S24, a first nitriding gas is supplied, whereby the boron-containing gas adsorbed on the substrate 100 reacts with the first nitriding gas and is nitridized.

[0021] After a predetermined time has elapsed since the start of step S24, in step S25, it is determined whether or not the processing of steps S21 to S24 has been executed a predetermined set number of times. If it is determined that steps S21 to S24 have not been executed the set number of times, the process returns to step S21, and steps S21 to S24 are executed again. If it is determined that steps S21 to S24 have been executed the set number of times, the process of FIG. 3 is terminated.

[0022] Another example of the method for forming the BN film 104 in step S2 will be described with reference to Fig. 4. Fig. 4 is a flow chart showing another example of the process for forming the BN film 104.

[0023] The process of Fig. 4 differs from the process of Fig. 3 in that hydrogen radical purge (HRP) is performed between step S23 and step S24 and between step S24 and step S25. The other configurations are the same as those of the process of Fig. 3. The following will mainly explain the configurations that are different from the process of Fig. 3.

[0024] First, steps S21 to S23 are performed in the same manner as in the process of FIG. 3. After a predetermined time has elapsed from the start of step S23, the supply of the purge gas is stopped, and in step S26, hydrogen radical purging is performed. In the hydrogen radical purging, hydrogen (H2) gas is turned into plasma and hydrogen radicals are generated. The hydrogen radicals react with halogens and the like that may be contained in the boron-containing gas adsorbed on the surface of the Ru film 103, and the halogens and the like are replaced with hydrogen, thereby modifying the boron-containing film.

[0025] After a predetermined time has elapsed since the start of step S26, the hydrogen radical purge is stopped, and the first nitriding gas is supplied in step S24, whereby the boron-containing gas adsorbed on the substrate 100 reacts with the first nitriding gas and is nitridized.

[0026] After a predetermined time has elapsed since the start of step S24, the supply of the first nitriding gas is stopped, and in step S27, hydrogen radical purging is performed. In the hydrogen radical purging, hydrogen gas is converted into plasma and hydrogen radicals are generated. The hydrogen radicals react with halogens and the like that may be contained in the BN film 104 formed on the surface of the Ru film 103, and the halogens and the like are replaced with hydrogen, thereby modifying the BN film 104. As a result, the BN film 104 can be formed with good film quality.

[0027] After a predetermined time has elapsed since the start of step S24, in step S25, it is determined whether or not the processes of steps S21, S22, S23, S26, S24, and S27 have been performed a predetermined number of times. If it is determined that steps S21, S22, S23, S26, S24, and S27 have not been performed the set number of times, the process returns to step S21, and steps S21, S22, S23, S26, S24, and S27 are performed again. If it is determined that steps S21, S22, S23, S26, S24, and S27 have been performed the set number of times, the process of FIG. 4 is terminated.

[0028] [Film forming equipment] The film forming apparatus 1 according to the embodiment will be described with reference to Fig. 5 and Fig. 6. Fig. 5 is a vertical cross-sectional view showing the film forming apparatus 1 according to the embodiment. Fig. 6 is a horizontal cross-sectional view showing the film forming apparatus 1 according to the embodiment.

[0029] The film forming apparatus 1 includes a processing chamber 10, a gas supply unit 30, an exhaust unit 40, a heating unit 50, a plasma generating mechanism 60, and a control unit 90.

[0030] The processing vessel 10 has a vertical cylindrical shape with a ceiling and an open bottom end. The processing vessel 10 is made of, for example, quartz. A quartz ceiling plate 11 is provided near the upper end of the processing vessel 10, and the area below the ceiling plate 11 is sealed. A cylindrically shaped manifold 12 is connected to the opening at the lower end of the processing vessel 10 via a seal member 13 such as an O-ring. The manifold 12 is made of, for example, metal.

[0031] Manifold 12 supports the lower end of processing vessel 10. Boat 14 is inserted into processing vessel 10 from below manifold 12. Boat 14 holds multiple substrates W at intervals in the vertical direction. Boat 14 holds each substrate W in a horizontal position. Boat 14 is made of, for example, quartz. Boat 14 has, for example, three support columns 15. Each support column 15 has grooves (not shown) formed at predetermined intervals in the vertical direction. Boat 14 holds multiple substrates W by the grooves. The substrates W are, for example, semiconductor wafers.

[0032] The boat 14 is placed on a table 17 via a quartz heat-insulating tube 16. The table 17 is supported on a rotation shaft 19 that penetrates a lid 18. The lid 18 opens and closes the opening at the lower end of the manifold 12. The lid 18 is made of, for example, stainless steel.

[0033] A magnetic fluid seal 20 is provided at the penetration portion of the rotating shaft 19. The magnetic fluid seal 20 airtightly seals the rotating shaft 19 and rotatably supports it. A seal member 21 is provided between the peripheral portion of the lid 18 and the lower end of the manifold 12. The seal member 21 maintains the airtightness inside the processing vessel 10. The seal member 21 is, for example, an O-ring.

[0034] The rotating shaft 19 is attached to the tip of an arm 22 supported by a lifting mechanism (not shown) such as a boat elevator. This allows the boat 14 and the lid 18 to be lifted and lowered as a unit and inserted into and removed from the processing vessel 10.

[0035] An opening 23 and an exhaust port 24 are provided in the side wall of the processing vessel 10. The opening 23 is formed to be elongated in the vertical direction so as to cover all of the substrates W supported by the boat 14 in the vertical direction. The exhaust port 24 is provided, for example, at a position opposite to the opening 23. The exhaust port 24 is formed to be elongated in the vertical direction so as to cover all of the substrates W supported by the boat 14 in the vertical direction.

[0036] The gas supply unit 30 is configured to be able to introduce various process gases used in the above-described film formation method into the process vessel 10. The gas supply unit 30 includes a boron supply unit 31, a DCS supply unit 32, an ammonia supply unit 33, and a nitrogen supply unit .

[0037] The boron supply unit 31 includes a boron supply pipe 31a in the processing vessel 10 and a boron supply path 31b outside the processing vessel 10. A boron supply source 31c, a mass flow controller 31d, and a valve 31e are provided in the boron supply path 31b in this order from the upstream side to the downstream side in the gas flow direction. Thus, the supply timing of the boron-containing gas from the boron supply source 31c is controlled by the valve 31e, and the flow rate is adjusted to a predetermined value by the mass flow controller 31d. The boron-containing gas flows from the boron supply path 31b into the boron supply pipe 31a and is discharged from the boron supply pipe 31a into the processing vessel 10.

[0038] The DCS supply unit 32 includes a DCS supply pipe 32a inside the processing vessel 10, and a DCS supply path 32b outside the processing vessel 10. A DCS source 32c, a mass flow controller 32d, and a valve 32e are provided on the DCS supply path 32b, in this order from the upstream side to the downstream side in the gas flow direction. Thus, the supply timing of the DCS gas from the DCS source 32c is controlled by the valve 32e, and the flow rate is adjusted to a predetermined value by the mass flow controller 32d. The DCS gas flows from the DCS supply path 32b into the DCS supply pipe 32a, and is discharged from the DCS supply pipe 32a into the processing vessel 10.

[0039] The ammonia supply unit 33 includes an ammonia supply pipe 33a inside the processing vessel 10, and an ammonia supply path 33b outside the processing vessel 10. An ammonia source 33c, a mass flow controller 33d, and a valve 33e are provided in the ammonia supply path 33b, in this order from the upstream side to the downstream side in the gas flow direction. Thus, the supply timing of the ammonia gas from the ammonia source 33c is controlled by the valve 33e, and the flow rate is adjusted to a predetermined value by the mass flow controller 33d. The ammonia gas flows from the ammonia supply path 33b into the ammonia supply pipe 33a, and is discharged from the ammonia supply pipe 33a into the processing vessel 10.

[0040] The nitrogen supply unit 34 includes a nitrogen supply pipe 34a inside the processing vessel 10, and a nitrogen supply path 34b outside the processing vessel 10. A nitrogen source 34c, a mass flow controller 34d, and a valve 34e are provided in the nitrogen supply path 34b, in this order from the upstream side to the downstream side in the gas flow direction. Thus, the supply timing of the nitrogen gas from the nitrogen source 34c is controlled by the valve 34e, and the flow rate is adjusted to a predetermined value by the mass flow controller 34d. The nitrogen gas flows from the nitrogen supply path 34b into the nitrogen supply pipe 34a, and is discharged from the nitrogen supply pipe 34a into the processing vessel 10.

[0041] The boron supply pipe 31a and the DCS supply pipe 32a extend vertically along the inner wall of the processing vessel 10, and are supported so as to penetrate the manifold 12, with their base ends bent in an L shape and extending horizontally. A plurality of boron outlet ports 31f are provided in the boron supply pipe 31a at a portion located within the processing vessel 10. A plurality of DCS outlet ports 32f are provided in the DCS supply pipe 32a at a portion located within the processing vessel 10.

[0042] The ammonia supply pipe 33a extends vertically along a plasma partition wall 61 in a plasma generation space P described later, and its base end is bent in an L-shape and extends horizontally, and is supported so as to penetrate the manifold 12. A plurality of ammonia discharge ports 33f are provided in a portion of the ammonia supply pipe 33a located inside the processing vessel 10.

[0043] The nitrogen supply pipe 34a extends horizontally inside the processing vessel 10 and is supported so as to penetrate the side wall of the manifold 12. The nitrogen supply pipe 34a has an open end, and discharges nitrogen gas from the opening.

[0044] The boron supply pipe 31a, the DCS supply pipe 32a, the ammonia supply pipe 33a and the nitrogen supply pipe 34a are made of, for example, quartz.

[0045] The outlets (boron outlet 31f, DCS outlet 32f, ammonia outlet 33f) are formed at predetermined intervals along the extension direction of the respective gas supply pipes (boron supply pipe 31a, DCS supply pipe 32a, ammonia supply pipe 33a). Each outlet discharges gas in the horizontal direction. The interval between each outlet is set to be the same as the interval between the substrates W held in the boat 14, for example. The height position of each outlet is set to the midpoint between the substrates W adjacent in the vertical direction. This allows each outlet to efficiently supply gas to the opposing surfaces between the adjacent substrates W.

[0046] The gas supply unit 30 may mix a plurality of types of gases and discharge the mixed gas from one gas supply pipe. The gas supply pipes (boron supply pipe 31a, DCS supply pipe 32a, ammonia supply pipe 33a, and nitrogen supply pipe 34a) may have different shapes and arrangements. The gas supply unit 30 may include a supply unit that supplies another gas in addition to the boron-containing gas, DCS gas, and ammonia gas.

[0047] The exhaust unit 40 includes a cover member 41, an exhaust pipe 42, a pressure control valve 43, and a vacuum pump 44. The cover member 41 is attached to a portion of the processing vessel 10 corresponding to the exhaust port 24 so as to cover the exhaust port 24. The cover member 41 extends vertically along the outer wall of the processing vessel 10. The exhaust pipe 42 is connected to a lower portion of the cover member 41. The pressure control valve 43 and the vacuum pump 44 are provided on the exhaust pipe 42. The pressure control valve 43 controls the pressure inside the processing vessel 10. The vacuum pump 44 exhausts the inside of the processing vessel 10.

[0048] The heating unit 50 is provided around the processing vessel 10. The heating unit 50 includes, for example, a heater. The heater heats each substrate W in the processing vessel 10 to a predetermined temperature by controlling the output.

[0049] The plasma generation mechanism 60 is provided on a part of the side wall of the processing vessel 10. The plasma generation mechanism 60 generates plasma from the ammonia gas supplied by the ammonia supply pipe 33a. The plasma generation mechanism 60 includes a plasma partition wall 61, a pair of plasma electrodes 62, a power supply line 63, an RF power supply 64, and an insulating protective cover 65.

[0050] The plasma compartment wall 61 is hermetically welded to the outer wall of the processing vessel 10. The plasma compartment wall 61 is made of, for example, quartz. The plasma compartment wall 61 has a concave shape in a horizontal cross section. The plasma compartment wall 61 covers the opening 23. The plasma compartment wall 61 forms a plasma generation space P that communicates with the inside of the processing vessel 10.

[0051] The pair of plasma electrodes 62 each have a shape elongated in the vertical direction. The pair of plasma electrodes 62 are provided on the outer surfaces of the opposing walls of the plasma compartment wall 61. The pair of plasma electrodes 62 are disposed opposite each other across the opposing walls of the plasma compartment wall 61 and the plasma generation space P. A power supply line 63 is connected to the lower end of each plasma electrode 62.

[0052] The power supply line 63 electrically connects each plasma electrode 62 to an RF power supply 64. For example, one end of the power supply line 63 is connected to the lower end of each plasma electrode 62, and the other end is connected to the RF power supply 64.

[0053] The RF power supply 64 is connected to the lower end of each plasma electrode 62 via a power supply line 63. The RF power supply 64 supplies RF power of, for example, 13.56 MHz to the pair of plasma electrodes 62. As a result, the RF power is applied to the plasma generation space P, and plasma is generated from the ammonia gas supplied to the plasma generation space P.

[0054] The insulating protective cover 65 is attached to the outside of the plasma compartment wall 61 so as to cover the plasma compartment wall 61. A coolant passage (not shown) may be provided in the inner portion of the insulating protective cover 65. In this case, the plasma electrode 62 can be cooled by flowing a coolant through the coolant passage.

[0055] The control unit 90 controls the operation of each part of the film forming apparatus 1. The control unit 90 may be, for example, a computer. A computer program for controlling the operation of each part of the film forming apparatus 1 is stored in a storage medium. The storage medium may be, for example, a flexible disk, a compact disk, a hard disk, a flash memory, a DVD, or the like.

[0056] [Operation of the Film Forming Apparatus] An example of the operation of the film forming apparatus 1 when carrying out the film forming method according to the embodiment will be described.

[0057] First, the control unit 90 controls the lifting mechanism (not shown) to load the boat 14 holding the multiple substrates W into the processing vessel 10, and hermetically closes the opening at the bottom of the processing vessel 10 with the lid 18. This causes the multiple substrates W to be accommodated in the processing vessel 10. Next, the control unit 90 controls the exhaust unit 40 to reduce the pressure inside the processing vessel 10. In addition, the control unit 90 controls the heating unit 50 to adjust the temperature of the substrates W to a first temperature. Each substrate W may be the substrate 100 described above (step S1 in FIG. 1).

[0058] Next, the control unit 90 controls the heating unit 50 to maintain the temperature of the substrate W at the first temperature, and controls the gas supply unit 30 to alternately and repeatedly supply the boron-containing gas and the ammonia gas into the processing vessel 10. As a result, a BN film 104 is formed on the Ru film 103 by the thermal ALD method (step S2 in FIG. 1).

[0059] Next, the control unit 90 controls the heating unit 50 to maintain the temperature of the substrate W at the first temperature, and controls the gas supply unit 30 to alternately and repeatedly supply DCS gas and ammonia gas into the processing vessel 10. When supplying ammonia gas into the processing vessel 10, the control unit 90 also controls the RF power supply 64 to supply RF power of, for example, 13.56 MHz to the pair of plasma electrodes 62 to generate plasma from the ammonia gas. As a result, a SiN film 105 is formed on the BN film 104 by the plasma ALD method (step S3 in FIG. 1).

[0060] Next, the control unit 90 increases the pressure inside the processing vessel 10 to atmospheric pressure and decreases the temperature inside the processing vessel 10 to the unloading temperature, and then controls the lifting mechanism to unload the boat 14 from the processing vessel 10. In this manner, a stacked film 106 in which the BN film 104 and the SiN film 105 are stacked in this order on the multiple substrates W held in the boat 14 can be formed.

[0061] [Example] First, five substrates W1 to W5 having a Ru film on the surface were prepared. Then, the sheet resistance of the Ru film on each of the substrates W1 to W5 was measured. Then, in the processing chamber 10 of the film formation apparatus 1, various films were formed on the Ru film on each of the substrates W1 to W5. The various films will be described later. After the various films were formed, the sheet resistance of the Ru film on each of the substrates W1 to W5 was measured again.

[0062] For the substrate W1, a SiN film having a thickness of 2 nm was formed on the Ru film by the plasma ALD method without forming a BN film. The SiN film was formed under the following condition B1.

[0063] For the substrate W2, a BN film having a thickness of 2 nm was formed on the Ru film by a thermal ALD method under the following condition A1.

[0064] For the substrate W3, a 1 nm thick BN film was formed on the Ru film by thermal ALD, and a 1 nm thick SiN film was formed on the BN film by plasma ALD. The BN film was formed under the following condition A1, and the SiN film was formed under the following condition B1.

[0065] For the substrate W4, a BN film having a thickness of 2 nm was formed on the Ru film by a thermal ALD method under the following condition A2.

[0066] For the substrate W5, a 1 nm thick BN film was formed on the Ru film by thermal ALD, and a 1 nm thick SiN film was formed on the BN film by plasma ALD. The BN film was formed under the following condition A2, and the SiN film was formed under the following condition B1.

[0067] (BN film formation conditions: Condition A1) Substrate temperature: 630℃ Gas supply sequence: (purge → boron-containing gas → purge → ammonia gas) repeated

[0068] (BN film formation conditions: Condition A2) Substrate temperature: 630℃ Gas supply sequence: (purge → boron-containing gas → purge → hydrogen radical purge → ammonia gas → hydrogen radical purge) repeated

[0069] (SiN film formation conditions: B1) Substrate temperature: 630℃ Gas supply sequence: (purge → DCS gas → purge → ammonia plasma) repeated

[0070] Figure 7 shows the results of measuring the sheet resistance of the Ru film. The sheet resistance of the Ru film in Figure 7 is shown as a relative value when the sheet resistance of the Ru film before various films are formed on the Ru film is set to 100%. The bar graph in Figure 7 shows the results for substrate W1, substrate W2, substrate W3, substrate W4, and substrate W5 from the left.

[0071] As shown in Fig. 7, the relative value of the sheet resistance of the Ru film is 168% for the substrate W1, and 100% for the substrates W2 to W5. This result shows that when a SiN film is formed on a Ru film without forming a BN film, the sheet resistance of the Ru film increases, whereas when a BN film is formed on the Ru film and then a SiN film is formed, the increase in the sheet resistance of the Ru film is suppressed. This is considered to be because when a BN film is not formed on the Ru film, the Ru film is silicided, whereas when a BN film is formed on the Ru film, the BN film functions as a barrier film that prevents the Ru film from being silicided.

[0072] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The above-described embodiments may be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended claims.

[0073] In the above embodiment, the silicon-containing gas is DCS gas, but the present disclosure is not limited thereto. For example, the silicon-containing gas can be selected from monochlorosilane gas, dichlorosilane gas, trichlorosilane gas, hexachlorodisilane gas, trisilylamine gas, or a combination thereof.

[0074] In the above embodiment, the first nitriding gas and the second nitriding gas are ammonia gas, but the present disclosure is not limited thereto. For example, the first nitriding gas and the second nitriding gas may be different gases. For example, the first nitriding gas and the second nitriding gas may be ammonia (NH3) gas, diazane (N2H2) gas, hydrazine (N2H4) gas, monomethylhydrazine (CH3(NH)NH2) gas, or a combination thereof, respectively.

[0075] In the above embodiment, the metal film is a Ru film, but the present disclosure is not limited to this. For example, the metal film may be a tungsten film, a cobalt film, or a molybdenum film.

[0076] In the above embodiment, the first film containing boron atoms and nitrogen atoms is a BN film, but the present disclosure is not limited thereto. For example, the first film may contain another element in addition to boron atoms and nitrogen atoms.

[0077] In the above embodiment, the second film containing silicon atoms and nitrogen atoms is a SiN film, but the present disclosure is not limited thereto. For example, the second film may contain another element in addition to silicon atoms and nitrogen atoms. For example, the second film may be a low-k film such as a SiCN film, a SiON film, a SiOCN film, a SiBN film, or a SiBCN film.

[0078] In the above embodiment, the case where the BN film is formed by the thermal ALD method has been described, but the present disclosure is not limited thereto. For example, the BN film may be formed by the plasma ALD method. However, from the viewpoint of reducing the surface roughness of the BN film, the thermal ALD method is preferable. For example, the BN film may be formed by the chemical vapor deposition (CVD) method. The CVD method may be the thermal CVD method or the plasma CVD method.

[0079] In the above embodiment, the case where the SiN film is formed by the plasma ALD method has been described, but the present disclosure is not limited thereto. For example, the SiN film may be formed by the thermal ALD method. For example, the SiN film may be formed by the CVD method. The CVD method may be the thermal CVD method or the plasma CVD method.

[0080] In the above embodiment, the film forming apparatus is a capacitively coupled plasma (CCP) apparatus, but the present disclosure is not limited thereto. For example, the film forming apparatus may be an inductively coupled plasma (ICP) apparatus, a remote plasma apparatus, or a microwave plasma apparatus.

[0081] In the above embodiment, the film forming apparatus is a batch type apparatus that processes a plurality of substrates at once, but the present disclosure is not limited to this. For example, the film forming apparatus may be a semi-batch type apparatus that rotates a plurality of substrates placed on a turntable in a processing vessel by the turntable and passes the substrates through a plurality of processing regions in order to process the substrates. For example, the film forming apparatus may be a single-wafer type apparatus that processes substrates one by one. [Explanation of symbols]

[0082] 100 Substrates 103 Ru membrane 104 BN membrane 105 SiN film

Claims

1. 1. A method for forming a film containing silicon atoms and nitrogen atoms on a surface of a substrate having a metal film on the surface, comprising the steps of: supplying a boron-containing gas and a first nitriding gas to the substrate to form a first film containing boron atoms and nitrogen atoms on the surface; supplying a silicon-containing gas and a second nitriding gas to the substrate to form a second film containing silicon atoms and nitrogen atoms on the first film; The film forming method includes the steps of:

2. The step of forming the first film is performed while maintaining the substrate at a first temperature, The step of forming the second film is performed while maintaining the substrate at the first temperature. The film forming method according to claim 1 .

3. The first temperature is 550° C. or more and 650° C. or less. The film forming method according to claim 2 .

4. the step of forming the first film includes forming the first film by a thermal ALD method in which the supply of the boron-containing gas and the supply of the first nitriding gas are alternately repeated. The film forming method according to claim 1 .

5. the step of forming the first film includes exposing the substrate to plasma generated from a hydrogen gas at least one of after the supply of the boron-containing gas and before the supply of the first nitriding gas, and after the supply of the first nitriding gas and before the supply of the boron-containing gas. The film forming method according to claim 1 .

6. the step of forming the second film includes forming the second film by a plasma ALD method in which the supply of the silicon-containing gas and the exposure of the substrate to plasma generated from the second nitriding gas are alternately repeated. The film forming method according to claim 1 .

7. The silicon-containing gas is dichlorosilane gas. The film forming method according to claim 1 .

8. The second nitriding gas is the same gas as the first nitriding gas. The film forming method according to claim 1 .

9. The metal film is a ruthenium film. The film forming method according to claim 1 .

10. A film forming apparatus for forming a film containing silicon atoms and nitrogen atoms on a surface of a substrate having a metal film on the surface, the apparatus comprising: a processing vessel for accommodating the substrate; a gas supply unit for supplying a gas into the processing chamber; A control unit; Equipped with The control unit is supplying a boron-containing gas and a first nitriding gas to the substrate to form a first film containing boron atoms and nitrogen atoms on the surface; supplying a silicon-containing gas and a second nitriding gas to the substrate to form a second film containing silicon atoms and nitrogen atoms on the first film; configured to: Film deposition equipment.

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