Film Formation Method and Film Formation Apparatus

Abstract

To provide a technique capable of controlling the nitrogen concentration in a silicon oxynitride film after forming the silicon oxynitride film.SOLUTION: A film forming method according to one aspect of the present disclosure includes a step (a) of forming a film containing silicon (Si), oxygen (O), and nitrogen (N) on a substrate, and a step (b) of exposing the substrate on which the film is formed to plasma generated from a plasma-generating gas containing Ar gas, and adjusting the concentration of nitrogen contained in the film by switching whether the plasma-generating gas contains a nitriding gas.SELECTED DRAWING: Figure 11

Description

Technical Field

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

Background Art

[0002] There is known a technique for modifying a silicon oxide film by using plasma obtained by plasmaizing a rare gas after forming the silicon oxide film (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure provides a technique capable of controlling the nitrogen concentration in a silicon oxynitride film after forming the silicon oxynitride film.

Means for Solving the Problems

[0005] A film forming method according to an aspect of the present disclosure includes: (a) a step of forming a film containing silicon (Si), oxygen (O), and nitrogen (N) on a substrate; and (b) a step of exposing the substrate on which the film is formed to plasma generated from a plasma generation gas containing Ar gas, and adjusting the nitrogen concentration contained in the film by switching whether or not to include a nitriding gas in the plasma generation gas. Step (a) includes repeating a cycle including a step of supplying a first processing gas containing a silicon-containing gas to the substrate, a step of supplying a second processing gas containing an oxidizing gas to the substrate, and a step of supplying a third processing gas containing a nitriding gas to the substrate. 。

Effects of the Invention

[0006] According to the present disclosure, the nitrogen concentration in the silicon oxynitride film can be controlled after forming the silicon oxynitride film.

Brief Description of the Drawings

[0007]

Figure 1

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Figure 10

Figure 11

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MODE FOR CARRYING OUT THE INVENTION

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

[0009] 〔Film Deposition Apparatus〕 Referring to FIGS. 1 to 10, a configuration example of the film deposition apparatus according to the embodiment will be described. FIG. 1 is a cross-sectional view showing a configuration example of the film deposition apparatus according to the embodiment. FIG. 2 is a plan view of the film deposition apparatus of FIG. 1. In FIG. 2, for convenience of explanation, the illustration of the top plate is omitted.

[0010] As shown in FIG. 1, the film deposition apparatus includes a vacuum chamber 1 having a generally circular planar shape, and a rotary table 2 provided in the vacuum chamber 1, having a rotation center at the center of the vacuum chamber 1 and for revolving a wafer W.

[0011] The vacuum chamber 1 is a processing chamber for accommodating the wafer W and performing a film deposition process on the surface of the wafer W to deposit a thin film. The vacuum chamber 1 includes a top plate 11 provided at a position facing a recess 24 (described later) of the rotary table 2, and a container body 12. A seal member 13 provided in an annular shape is provided at the periphery of the upper surface of the container body 12. The top plate 11 is configured to be detachable from the container body 12. The diameter dimension (inner diameter dimension) of the vacuum chamber 1 in a plan view is not limited, but may be, for example, about 1100 mm.

[0012] A separation gas supply pipe 51 for supplying a separation gas is connected to the central portion on the upper surface side in the vacuum chamber 1 to suppress mixing of different process gases with each other in the central region C in the vacuum chamber 1.

[0013] The rotary table 2 is fixed to a core portion 21 having a generally cylindrical shape at the center portion, and is configured to be rotatable about a vertical axis by a drive unit 23 around the vertical axis with respect to a rotary shaft 22 connected to the lower surface of the core portion 21 and extending in the vertical direction. In the example shown in FIG. 2, it is clockwise. The diameter dimension of the rotary table 2 is not limited, but may be, for example, about 1000 mm.

[0014] The drive unit 23 is provided with an encoder 25 for detecting the rotation angle of the rotary shaft 22. In the embodiment, the rotation angle of the rotary shaft 22 detected by the encoder 25 is transmitted to the control unit 120 and used by the control unit 120 to identify the position of the wafer W placed on each recess 24 on the rotary table 2.

[0015] The rotary shaft 22 and the drive unit 23 are housed in the case body 20. The flange portion on the upper surface side of the case body 20 is airtightly attached to the lower surface of the bottom surface portion 14 of the vacuum chamber 1. A purge gas supply pipe 72 for supplying Ar gas or the like as a purge gas (separation gas) to the lower region of the rotary table 2 is connected to the case body 20.

[0016] The outer peripheral side of the core portion 21 on the bottom surface portion 14 of the vacuum chamber 1 is formed in an annular shape so as to approach the rotary table 2 from below to form a protruding portion 12a.

[0017] On the surface of the rotary table 2, circular recesses 24 capable of placing a wafer W with a diameter dimension of, for example, 300 mm are formed. The recesses 24 are provided at a plurality of locations, for example, six locations, along the rotation direction of the rotary table 2 (the direction indicated by the arrow A in FIG. 2). The recesses 24 have an inner diameter that is slightly larger than the diameter of the wafer W, specifically, about 1 mm to 4 mm larger. The depth of the recesses 24 is substantially equal to the thickness of the wafer W or configured to be larger than the thickness of the wafer W. Therefore, when the wafer W is accommodated in the recesses 24, the surface of the wafer W and the surface of the flat region of the rotary table 2 where the wafer W is not placed are at the same height, or the surface of the wafer W is lower than the surface of the rotary table 2. Further, through holes (not shown) through which, for example, three lifting pins described later for lifting the wafer W from below are formed are formed in the bottom surface of the recesses 24.

[0018] As shown in FIG. 2, along the rotation direction of the rotary table 2, a first processing region P1, a second processing region P2, and a third processing region P3 are provided so as to be separated from each other. At a position facing the passage region of the recess 24 in the rotary table 2, a plurality of gas nozzles made of, for example, quartz are radially arranged at intervals in the circumferential direction of the vacuum chamber 1. In the present embodiment, the plurality of gas nozzles are a first processing gas nozzle 31, a second processing gas nozzle 32, third processing gas nozzles 33 to 35, and separation gas nozzles 41 and 42.

[0019] The first processing gas nozzle 31, the second processing gas nozzle 32, the third processing gas nozzles 33 to 35, and the separation gas nozzles 41 and 42 are arranged between the rotary table 2 and the top plate 11. Each of the first processing gas nozzle 31, the second processing gas nozzle 32, the third processing gas nozzles 33 and 34, and the separation gas nozzles 41 and 42 is attached so as to horizontally extend toward the rotary table 2 from the outer peripheral wall of the vacuum chamber 1 toward the central region C. The third processing gas nozzle 35 extends from the outer peripheral wall of the vacuum chamber 1 toward the central region C, then bends and extends counterclockwise (in the direction opposite to the rotation direction of the rotary table 2) along the central region C linearly. In the example shown in FIG. 2, from the transfer port 15, which will be described later, in the clockwise direction (the rotation direction of the rotary table 2), the third processing gas nozzles 33 to 35, the separation gas nozzle 41, the first processing gas nozzle 31, the separation gas nozzle 42, and the second processing gas nozzle 32 are arranged in this order.

[0020] The first processing gas nozzle 31 forms a first processing gas supply unit. The lower region of the first processing gas nozzle 31 is the first processing region P1 to which the first processing gas is supplied. The first processing gas nozzle 31 is connected to a supply source (not shown) of the first processing gas via a flow rate adjustment valve. On the lower surface side (the side facing the rotary table 2) of the first processing gas nozzle 31, a plurality of gas holes 36 are formed along the radial direction of the rotary table 2, and the first processing gas nozzle 31 discharges the first processing gas from the plurality of gas holes 36. In the present embodiment, the first processing gas is a gas containing a silicon-containing gas.

[0021] The second processing gas nozzle 32 forms a second processing gas supply unit. The lower region of the second processing gas nozzle 32 is a second processing region P2 where the second processing gas is supplied. The second processing gas nozzle 32 is connected to a supply source (not shown) of the second processing gas via a flow rate adjustment valve. A plurality of gas holes 36 are formed along the radial direction of the rotary table 2 on the lower surface side (the side facing the rotary table 2) of the second processing gas nozzle 32, and the second processing gas nozzle 32 discharges the second processing gas from the plurality of gas holes 36. In the present embodiment, the second processing gas is a gas containing an oxidizing gas.

[0022] The third processing gas nozzles 33 to 35 each form a third processing gas supply unit. The lower regions of the third processing gas nozzles 33 to 35 are a third processing region P3 where the third processing gas and the plasma generating gas are supplied. The third processing gas nozzles 33 to 35 are connected to a supply source (not shown) of the third processing gas via a flow rate adjustment valve. A plurality of gas holes 36 are formed along the radial direction of the rotary table 2 on the lower surface side (the side facing the rotary table 2) of the third processing gas nozzle 33, and the third processing gas nozzles 33 to 35 discharge the third processing gas from the plurality of gas holes 36. In the present embodiment, the third processing gas is a gas containing a nitriding gas, and the plasma generating gas is a gas containing Ar gas. Note that the third processing gas nozzles 33 to 35 may be replaced by one gas nozzle. In this case, for example, similar to the second processing gas nozzle 32, a gas nozzle extending from the outer peripheral wall of the vacuum chamber 1 toward the central region C may be provided.

[0023] The separation gas nozzles 41 and 42 each form a separation gas supply unit. The separation gas nozzles 41 and 42 are provided to form a separation region D that separates the first processing region P1 from the second processing region P2 and the third processing region P3 and the first processing region P1. In the present embodiment, the separation gas is an inert gas or a noble gas.

[0024] FIG. 3 is a cross-sectional view along a concentric circle of the rotary table 2 of the film forming apparatus of FIG. 1, and is a cross-sectional view from the separation region D through the first processing region P1 to the separation region D.

[0025] On the top plate 11 of the vacuum chamber 1 in the separation region D, a generally fan-shaped convex portion 4 is provided. The convex portion 4 is attached to the back surface of the top plate 11. In the vacuum chamber 1, a flat and low ceiling surface (hereinafter referred to as "first ceiling surface 44") which is the lower surface of the convex portion 4, and ceiling surfaces (hereinafter referred to as "second ceiling surfaces 45") which are higher than the first ceiling surface 44 and are located on both circumferential sides of the first ceiling surface 44, are formed.

[0026] As shown in FIG. 2, the convex portion 4 forming the first ceiling surface 44 has a fan-shaped planar shape with its top cut in an arc shape. In the convex portion 4, a groove portion 43 is formed so as to extend in the radial direction at the center in the circumferential direction. The separation gas nozzles 41 and 42 are accommodated in the groove portion 43. Note that the peripheral edge of the convex portion 4 (the portion on the outer edge side of the vacuum chamber 1) is bent in an L shape so as to face the outer end surface of the rotary table 2 and be slightly separated from the container body 12 in order to prevent the mixing of the respective processing gases.

[0027] Above the first processing gas nozzle 31, a nozzle cover 230 is provided in order to allow the first processing gas to flow along the wafer W and to allow the separation gas to flow through the top plate 11 side of the vacuum chamber 1 while avoiding the vicinity of the wafer W. As shown in FIG. 3, the nozzle cover 230 includes a cover body 231 and a rectifying plate 232. The cover body 231 has a generally box shape with an opening on the lower surface side for accommodating the first processing gas nozzle 31. The rectifying plate 232 is a plate-like body connected to the upstream side and the downstream side in the rotation direction of the rotary table 2 at the opening end on the lower surface side of the cover body 231, respectively. The side wall surface of the cover body 231 on the rotation center side of the rotary table 2 extends toward the rotary table 2 so as to face the tip of the first processing gas nozzle 31. Also, the side wall surface of the cover body 231 on the outer edge side of the rotary table 2 is cut out so as not to interfere with the first processing gas nozzle 31. Note that the nozzle cover 230 is not essential and may be provided as necessary.

[0028] As shown in FIG. 2, a plasma source 80 is provided above the third processing gas nozzles 33 to 35 to plasmaize the plasma processing gas discharged into the vacuum chamber 1. The plasma source 80 generates inductively coupled plasma using an antenna 83.

[0029] FIG. 4 is a cross-sectional view of the plasma source 80 provided in the film forming apparatus of FIG. 1. FIG. 5 is an exploded perspective view of the plasma source 80 provided in the film forming apparatus of FIG. 1. FIG. 6 is a perspective view of an example of a housing 90 provided in the plasma source 80 of FIG. 5.

[0030] The plasma source 80 is configured by winding an antenna 83 formed of a metal wire or the like in a coil shape, for example, three times around the vertical axis. Further, the plasma source 80 is arranged so as to surround a belt-like region extending in the radial direction of the rotary table 2 in a plan view and straddle the diameter portion of the wafer W on the rotary table 2.

[0031] The antenna 83 is connected to an RF power source 85 having a frequency of, for example, 13.56 MHz via a matcher 84. The antenna 83 is provided so as to be hermetically partitioned from the internal region of the vacuum chamber 1. In FIGS. 4 and 5, a connection electrode 86 for electrically connecting the antenna 83, the matcher 84, and the RF power source 85 is provided.

[0032] In addition, the antenna 83 may be provided with a configuration that can be bent up and down, a vertical movement mechanism that can automatically bend the antenna 83 up and down, and a mechanism that can move the portion on the center side of the rotary table 2 up and down as needed. Those configurations are omitted in FIG. 4.

[0033] As shown in FIGS. 4 and 5, an opening 11a that opens in a substantially fan shape in a plan view is formed in the top plate 11 above the third processing gas nozzles 33 to 35.

[0034] As shown in FIG. 4, the opening 11a has an annular member 82 that is airtightly provided along the opening edge of the opening 11a. A housing 90, which will be described later, is airtightly provided on the inner peripheral surface side of the annular member 82. That is, the annular member 82 is airtightly provided such that its outer peripheral side contacts the inner peripheral surface 11b of the opening 11a of the top plate 11 and its inner peripheral side contacts the flange portion 90a of the housing 90, which will be described later. And via the annular member 82, a housing 90 made of a dielectric such as quartz, for example, is provided in the opening 11a to position the antenna 83 below the top plate 11. The bottom surface of the housing 90 constitutes the ceiling surface 46 of the third processing region P3.

[0035] As shown in FIG. 6, the housing 90 has a peripheral edge on the upper side that horizontally extends in a flange shape over the circumferential direction to form a flange portion 90a, and in a plan view, the central portion is formed to be recessed toward the inner region of the vacuum vessel 1 on the lower side.

[0036] The housing 90 is arranged to straddle the diameter portion of the wafer W in the radial direction of the rotary table 2 when the wafer W is positioned below the housing 90. Note that a seal member 11c such as an O-ring is provided between the annular member 82 and the top plate 11 (see FIG. 4).

[0037] The internal atmosphere of the vacuum vessel 1 is airtightly set via the annular member 82 and the housing 90. Specifically, the annular member 82 and the housing 90 are fitted into the opening 11a, and then the housing 90 is pressed downward in the circumferential direction by a pressing member 91 formed in a frame shape along the contact portion of the annular member 82 and the housing 90 on the upper surfaces of the annular member 82 and the housing 90. Further, the pressing member 91 is fixed to the top plate 11 by bolts (not shown) or the like. Thereby, the internal atmosphere of the vacuum vessel 1 is airtightly set. Note that in FIG. 5, the annular member 82 is omitted for simplicity of illustration.

[0038] As shown in FIG. 6, a protrusion 92 that extends vertically toward the rotary table 2 is formed on the lower surface of the housing 90 so as to surround the third processing region P3 on the lower side of the housing 90 along the circumferential direction. The third processing gas nozzles 33 to 35 described above are housed in the region surrounded by the inner circumferential surface of the protrusion 92, the lower surface of the housing 90, and the upper surface of the rotary table 2. Note that the protrusion 92 at the base ends of the third processing gas nozzles 33 to 35 (on the inner wall side of the vacuum chamber 1) is notched in a substantially arc shape along the outer shapes of the third processing gas nozzles 33 to 35.

[0039] As shown in FIG. 4, a protrusion 92 is formed over the circumferential direction on the lower side (the third processing region P3 side) of the housing 90. The seal member 11c is not directly exposed to the plasma by the protrusion 92, that is, it is isolated from the third processing region P3. Therefore, even if the plasma tries to diffuse from the third processing region P3 to the seal member 11c side, for example, it will pass through the lower part of the protrusion 92, so the plasma will be deactivated before reaching the seal member 11c.

[0040] FIG. 7 is another cross-sectional view of the plasma source 80 provided in the film forming apparatus of FIG. 1, and is a longitudinal sectional view showing the vacuum chamber 1 cut along the rotation direction of the rotary table 2. As shown in FIG. 7, since the rotary table 2 rotates clockwise during plasma processing, Ar gas tends to enter from the gap between the rotary table 2 and the protrusion 92 to the lower side of the housing 90 along with the rotation of the rotary table 2. Therefore, in order to prevent the intrusion of Ar gas to the lower side of the housing 90 through the gap, gas is discharged from the lower side of the housing 90 to the gap. Specifically, for the gas hole 36 of the third processing gas nozzle 33, as shown in FIGS. 4 and 7, it is arranged so as to face the gap, that is, on the upstream side and downward in the rotation direction of the rotary table 2. The angle θ at which the gas hole 36 of the third processing gas nozzle 33 faces the vertical axis may be, for example, about 45° as shown in FIG. 7, or about 90° so as to face the inner surface of the protrusion 92. That is, the angle θ at which the gas hole 36 faces can be set according to the application within a range of about 45° to 90° that can appropriately prevent the intrusion of Ar gas.

[0041] FIG. 8 is a perspective view showing an enlarged view of the third processing gas nozzles 33 to 35 provided in the third processing region P3. As shown in FIG. 8, the third processing gas nozzle 33 is a nozzle that can cover the entire recess 24 where the wafer W is placed and supply the plasma processing gas to the entire surface of the wafer W. On the other hand, the third processing gas nozzle 34 is provided slightly above the third processing gas nozzle 33 and substantially overlapping the third processing gas nozzle 33, and has a length of about half of the third processing gas nozzle 33. Further, the third processing gas nozzle 35 extends along the radius on the downstream side in the rotation direction of the rotary table 2 in the fan-shaped third processing region P3 from the outer peripheral wall of the vacuum chamber 1, and has a shape that bends linearly along the central region C when it reaches the vicinity of the central region C. Hereinafter, for ease of distinction, the third processing gas nozzle 33 that covers the whole is also referred to as the base nozzle 33, the third processing gas nozzle 34 that covers only the outside is also referred to as the outer nozzle 34, and the third processing gas nozzle 35 that extends to the inside is also referred to as the shaft side nozzle 35.

[0042] The base nozzle 33 is a gas nozzle for supplying the plasma processing gas to the entire surface of the wafer W, and discharges the plasma processing gas toward the protrusion 92 that constitutes the side surface partitioning the third processing region P3, as described with reference to FIG. 7.

[0043] On the other hand, the outer nozzle 34 is a nozzle for mainly supplying the plasma processing gas to the outer region of the wafer W.

[0044] The axial-side nozzle 35 is a nozzle for mainly supplying the plasma processing gas to the central region near the axis side of the rotary table 2 of the wafer W.

[0045] When only one third processing gas nozzle is provided, only the base nozzle 33 may be provided.

[0046] Next, the Faraday shield 95 of the plasma source 80 will be described in more detail. As shown in FIGS. 4 and 5, above the housing 90, a grounded Faraday shield 95 made of a conductive plate-like body, for example, copper, which is formed so as to generally follow the internal shape of the housing 90, is accommodated. The Faraday shield 95 includes a horizontal surface 95a horizontally locked along the bottom surface of the housing 90, and a vertical surface 95b extending upward in the circumferential direction from the outer end of the horizontal surface 95a, and may be configured to have a generally hexagonal shape in plan view, for example.

[0047] FIG. 9 is a plan view of an example of the plasma source 80 in FIG. 5, showing an example of the plasma source 80 in which the details of the structure of the antenna 83 and the vertical movement mechanism are omitted. FIG. 10 is a perspective view showing a part of the Faraday shield 95 provided in the plasma source 80.

[0048] When viewed from the center of rotation of the rotary table 2, the upper edge of the Faraday shield 95 on the right and left sides extends horizontally to the right and left, respectively, to form the support portion 96. Between the Faraday shield 95 and the housing 90, a frame body 99 is provided that supports the support portion 96 from below and is supported by the center region C side of the housing 90 and the flange portion 90a on the outer edge side of the rotary table 2 (see Fig. 5).

[0049] When an electric field reaches the wafer W, the electrical wiring and the like formed inside the wafer W may be electrically damaged. Therefore, as shown in Fig. 10, on the horizontal plane 95a, a number of slits 97 are formed to prevent the electric field component of the electric field and magnetic field (electromagnetic field) generated by the antenna 83 from reaching the lower wafer W and to allow the magnetic field to reach the wafer W.

[0050] As shown in Figs. 9 and 10, the slits 97 are formed at a position below the antenna 83 in the circumferential direction so as to extend in a direction orthogonal to the winding direction of the antenna 83. The slits 97 are formed to have a width dimension of about 1 / 10000 or less of the wavelength corresponding to the frequency of the RF power supplied to the antenna 83. Also, on one end side and the other end side in the length direction of each slit 97, conductive paths 97a formed from a grounded conductor or the like are arranged in the circumferential direction so as to close the open end of the slit 97. An opening 98 is formed in a region of the Faraday shield 95 outside the formation region of these slits 97, that is, on the central side of the region where the antenna 83 is wound, for checking the light emission state of the plasma through this region.

[0051] As shown in FIG. 5, on the horizontal plane 95a of the Faraday shield 95, an insulating plate 94 made of quartz or the like with a thickness dimension of about 2 mm, for example, is laminated to ensure insulation between the plasma source 80 placed above the Faraday shield 95. That is, the plasma source 80 is arranged to cover the inside of the vacuum chamber 1 (wafer W on the rotary table 2) via the housing 90, the Faraday shield 95, and the insulating plate 94.

[0052] Next, other components of the film forming apparatus according to the embodiment will be described.

[0053] As shown in FIGS. 1 and 2, on the outer peripheral side of the rotary table 2, at a position below the rotary table 2, a side ring 100 which is a cover body is arranged. On the upper surface of the side ring 100, a first exhaust port 61 and a second exhaust port 62 are formed so as to be separated from each other in the circumferential direction. In other words, two exhaust ports are formed on the bottom surface of the vacuum chamber 1, and the first exhaust port 61 and the second exhaust port 62 are formed in the side ring 100 at positions corresponding to these exhaust ports.

[0054] The first exhaust port 61 is formed at a position closer to the separation region D between the first processing gas nozzle 31 and the separation region D located on the downstream side in the rotation direction of the rotary table 2 with respect to the first processing gas nozzle 31. The second exhaust port 62 is formed at a position closer to the separation region D between the plasma source 80 and the separation region D on the downstream side in the rotation direction of the rotary table 2 with respect to the plasma source 80.

[0055] The first exhaust port 61 is an exhaust port for exhausting the first processing gas and the separation gas, and the second exhaust port 62 is an exhaust port for exhausting the plasma processing gas and the separation gas. As shown in FIG. 1, the first exhaust port 61 and the second exhaust port 62 are each connected to a vacuum pump 64, which is a vacuum exhaust mechanism, by an exhaust pipe 63 provided with a pressure adjustment unit 65 such as a butterfly valve.

[0056] As described above, since the housing 90 is arranged from the center region C side to the outer edge side, the gas flowing from the upstream side in the rotation direction of the rotary table 2 to the second processing region P2 may have its flow toward the second exhaust port 62 restricted by the housing 90. Therefore, a groove-shaped gas flow path 101 for the gas to flow is formed on the upper surface of the side ring 100 on the outer peripheral side of the housing 90.

[0057] As shown in FIG. 1, at the central portion on the lower surface of the top plate 11, a protruding portion 5 is provided which is formed in a substantially annular shape continuously in the circumferential direction along with the portion on the center region C side of the convex portion 4, and whose lower surface is formed at the same height as the lower surface (the first ceiling surface 44) of the convex portion 4. Above the core portion 21 on the rotation center side of the rotary table 2 with respect to the protruding portion 5, a labyrinth structure portion 110 for suppressing the mixing of various gases in the center region C is arranged.

[0058] As described above, since the housing 90 is formed up to a position closer to the center region C side, the core portion 21 that supports the central portion of the rotary table 2 is formed on the rotation center side such that the upper portion of the rotary table 2 avoids the housing 90. Therefore, in the center region C, various gases are more likely to mix than on the outer edge portion side. Therefore, by forming the labyrinth structure portion 110 above the core portion 21, a gas flow path can be created and the mixing of gases can be prevented.

[0059] As shown in FIG. 1, a heater unit 7 which is a heating mechanism is provided in the space between the rotary table 2 and the bottom surface portion 14 of the vacuum chamber 1. The heater unit 7 is configured to be able to heat the wafer W on the rotary table 2 via the rotary table 2 to, for example, about room temperature to 700°C. In FIG. 1, a cover member 71 is provided on the side of the heater unit 7, and a covering member 7a that covers the upper side of the heater unit 7 is provided. Further, on the bottom surface portion 14 of the vacuum chamber 1, a plurality of purge gas supply pipes 73 for purging the arrangement space of the heater unit 7 are provided at a plurality of locations in the circumferential direction below the heater unit 7.

[0060] As shown in Fig. 2, a transfer port 15 for transferring the wafer W is formed on the side wall of the vacuum chamber 1 between the transfer arm 10 and the rotary table 2. The transfer port 15 is configured to be hermetically opened and closed more tightly than the gate valve G.

[0061] The recess 24 of the rotary table 2 is located at a position facing the transfer port 15 and the wafer W is transferred between the transfer port 15 and the transfer arm 10. Therefore, at a location corresponding to the transfer position on the lower side of the rotary table 2, a lifting pin and a lifting mechanism (not shown) for lifting the wafer W from the back surface through the recess 24 are provided.

[0062] In addition, the film forming apparatus according to the embodiment is provided with a control unit 120 composed of a computer for controlling the operation of the entire apparatus. A program for performing the substrate processing described later is stored in the memory of the control unit 120. The program is composed of a group of steps for executing various operations of the apparatus, and is installed from a storage unit 121, which is a storage medium such as a hard disk, a compact disk, a magneto-optical disk, a memory card, or a flexible disk, into the control unit 120.

[0063] 〔Film Forming Method〕 Referring to Fig. 11, the film forming method according to the embodiment will be described by taking the case of forming a SiON film using the above-described film forming apparatus as an example. The film forming method according to the embodiment is performed by the control unit 120 controlling the operation of the entire film forming apparatus.

[0064] As shown in Fig. 11, the film forming method according to the embodiment forms a SiON film by performing a SiON film forming step S1 and a plasma annealing step S2 in this order.

[0065] First, the wafer W is carried into the vacuum chamber 1. When carrying in the wafer W, the gate valve G is opened, and while intermittently rotating the rotary table 2, the wafer W is placed on the rotary table 2 through the transfer port 15 by the transfer arm 10. After placing the wafer W, the transfer arm 10 is retracted outside the vacuum chamber 1, and the gate valve G is closed.

[0066] Next, the SiON film forming step S1 is performed. In the SiON film forming step S1, while rotating the rotary table 2 in a state where the inside of the vacuum chamber 1 is controlled to a predetermined pressure by the vacuum pump 64 and the pressure adjustment unit 65, the wafer W is heated to a predetermined temperature by the heater unit 7. At this time, a separation gas (for example, Ar gas) is supplied from the separation gas nozzles 41 and 42. Further, a first processing gas (for example, DIPAS gas) is supplied from the first processing gas nozzle 31. Further, a second processing gas (for example, a mixed gas of O3 gas and O2 gas) is supplied from the second processing gas nozzle 32. Further, a third processing gas (for example, a mixed gas of NH3 gas and Ar gas) is supplied from the third processing gas nozzles 33 to 35. Further, RF power is supplied from the RF power supply 85 to the antenna 83 to ignite the plasma and generate plasma from the third processing gas.

[0067] In the SiON film forming step S1, due to the rotation of the rotary table 2, the DIPAS gas is adsorbed in the first processing region P1 on the surface of the wafer W, and then the DIPAS gas adsorbed on the wafer W in the second processing region P2 is oxidized by the O3 gas. As a result, a molecular layer of SiO2, which is a thin film component, is formed in one or more layers and deposited on the wafer W. When the rotary table 2 further rotates, the wafer W reaches the third processing region P3, and nitrogen is introduced into the SiO2 molecular layer. Thereby, a molecular layer of SiON is formed in one or more layers on the wafer W.

[0068] In such a state, by continuing the rotation of the rotary table 2, a cycle including the adsorption of DIPAS gas onto the surface of the wafer W, the oxidation of the DIPAS gas components adsorbed on the surface of the wafer W, and the introduction of nitrogen into the SiO2 molecular layer is repeated. That is, the formation of the SiON film by the ALD method is performed by the rotation of the rotary table 2. After the film thickness of the SiON film reaches the target film thickness, the supply of RF power from the RF power supply 85 to the antenna 83 is stopped. Also, the supply of the first processing gas, the second processing gas, and the third processing gas is stopped.

[0069] Next, a plasma annealing step S2 is performed. In the plasma annealing step S2, while rotating the rotary table 2 in a state where the inside of the vacuum chamber 1 is controlled to a predetermined pressure by the vacuum pump 64 and the pressure adjustment unit 65, the wafer W is heated to a predetermined temperature by the heater unit 7. At this time, a separation gas (for example, Ar gas) is supplied from the separation gas nozzles 41 and 42. Also, the first processing gas is not supplied from the first processing gas nozzle 31, and the second processing gas (for example, a mixed gas of O3 gas and O2 gas) is supplied from the second processing gas nozzle 32. Further, a plasma generation gas (for example, Ar gas, a mixed gas of Ar gas and NH3 gas) is supplied from the third processing gas nozzles 33 to 35. Also, RF power is supplied from the RF power supply 85 to the antenna 83 to ignite the plasma and generate plasma from the plasma generation gas.

[0070] In the plasma annealing step S2, the nitrogen concentration in the film of the SiON film formed in the SiON film formation step S1 is adjusted by switching whether or not to include NH3 gas in the plasma generation gas. When it is selected not to include NH3 gas in the plasma generation gas, the active species (Ar ions, etc.) of the Ar gas constituting the plasma react with the SiON film, and nitrogen in the SiON film desorbs, so that the nitrogen concentration in the film of the SiON film decreases. On the other hand, when it is selected to include NH3 gas in the plasma generation gas, the active species (NH2 radicals, NH radicals, etc.) of the NH3 gas constituting the plasma react with the SiON film, and nitrogen is introduced into the SiON film, so that the nitrogen concentration in the film of the SiON film increases.

[0071] In such a state, by continuing the rotation of the rotary table 2, the SiON film formed on the wafer W is exposed to the plasma generated from the plasma generation gas, and the nitrogen concentration in the film is adjusted. Then, after a predetermined time has elapsed, the supply of RF power from the RF power supply 85 to the antenna 83 is stopped. Also, the supply of the second processing gas and the plasma generation gas is stopped. After that, after stopping the rotation of the rotary table 2, the processed wafer W is carried out of the vacuum chamber 1, and the process is completed.

[0072] According to the film formation method of the embodiment described above, the plasma annealing step S2 is performed after the SiON film formation step S1, and the nitrogen concentration contained in the SiON film is adjusted by switching whether or not to include NH3 gas in the plasma generation gas in the plasma annealing step S2. Thereby, the nitrogen concentration in the film of the SiON film can be controlled after forming the SiON film.

[0073] In the film formation method of the above embodiment, the case where the SiON film formation step S1 and the plasma annealing step S2 are performed once in this order has been described, but it is not limited to this. For example, the SiON film formation step S1 and the plasma annealing step S2 may be alternately repeated.

[0074] 〔Example〕 (Example 1) In Example 1, in the above-described film forming apparatus, after performing the SiON film formation step S1, the plasma annealing step S2 was performed to form a SiON film on the silicon wafer. In Example 1, in the plasma annealing step S2, Ar gas was supplied without supplying NH3 gas from the third processing gas nozzles 33 to 35, and the processing times were set to 0 minutes (without the plasma annealing step S2), 1 minute, 5 minutes, and 10 minutes. Next, the refractive index and film thickness were measured for each SiON film. The conditions of the SiON film formation step S1 and the conditions of the plasma annealing step S2 are as follows.

[0075] <SiON film formation step S1> Wafer temperature: 400 °C Pressure inside the vacuum chamber 1: 1.8 Torr to 2.0 Torr (240 Pa to 267 Pa) RF power: 4000 W First process gas nozzle 31: DIPAS gas Second process gas nozzle 32: Mixed gas of O3 gas and O2 gas Third process gas nozzles 33 - 35: Mixed gas of Ar gas and NH3 gas Rotation speed of the rotary table 2: 10 rpm <Plasma annealing process S2> Wafer temperature: 400 °C Pressure inside the vacuum chamber 1: 1.8 Torr to 2.0 Torr (240 Pa to 267 Pa) RF power: 4000 W First process gas nozzle 31: Not used (no supply of the first process gas) Second process gas nozzle 32: Mixed gas of O3 gas and O2 gas Third process gas nozzles 33 - 35: Ar gas Rotation speed of the rotary table 2: 10 rpm Processing time: 0 min, 1 min, 5 min, 10 min

[0076] Figure 12 is a diagram showing the measurement results of the refractive index of the SiON film. In Figure 12, the horizontal axis represents the processing time [min] of the plasma annealing process S2, and the vertical axis represents the refractive index of the SiON film.

[0077] As shown in FIG. 12, in the plasma annealing step S2, by supplying Ar gas without supplying NH3 gas from the third processing gas nozzles 33 to 35, it can be seen that the refractive index of the SiON film decreases. Also, it can be seen that the longer the processing time of the plasma annealing step S2, the lower the refractive index of the SiON film. Here, in the SiON film, it is known that the higher the composition ratio of oxygen (O) to nitrogen (N) in the film, the lower the refractive index. Considering this, in the plasma annealing step S2, by supplying Ar gas without supplying NH3 gas from the third processing gas nozzles 33 to 35 and increasing the processing time, it can be said that the composition ratio of oxygen to nitrogen in the SiON film can be increased. Thus, it has been shown that in the plasma annealing step S2, by supplying Ar gas without supplying NH3 gas from the third processing gas nozzles 33 to 35 and changing the processing time, the nitrogen concentration and oxygen concentration in the SiON film can be controlled.

[0078] FIG. 13 is a diagram showing the measurement results of the film thickness of the SiON film. In FIG. 13, the horizontal axis represents the processing time [min] of the plasma annealing step S2, and the vertical axis represents the film thickness [Å] of the SiON film.

[0079] As shown in FIG. 13, it can be seen that even when the processing time of the plasma annealing step S2 changes, the film thickness of the SiON film is almost the same. From this result, it can be said that performing the plasma annealing step S2 has almost no effect on the film thickness of the SiON film. Also, although not shown, even when the processing time of the plasma annealing step S2 changes, the in-plane uniformity of the film thickness of the SiON film is also almost the same. From this result, it can be said that performing the plasma annealing step S2 has almost no effect on the in-plane uniformity of the film thickness of the SiON film.

[0080] (Example 2) In Example 2, in the above-described film-forming apparatus, SiON films were formed under seven different conditions (Conditions 1 to 7), and the refractive index and film thickness were measured for each SiON film. Further, by using a known relational expression between the refractive index of the SiON film and the nitrogen concentration and oxygen concentration in the SiON film, the nitrogen concentration and oxygen concentration in the SiON film corresponding to the measured refractive index of the SiON film were calculated.

[0081] Condition 1 is a condition where the plasma annealing step S2 was not performed after the SiON film forming step S1.

[0082] Conditions 2 to 5 are conditions where the plasma annealing step S2 was performed after the SiON film forming step S1. In Condition 2, in the plasma annealing step S2, O3 gas and O2 gas were supplied from the second processing gas nozzle 32, and Ar gas was supplied without supplying NH3 gas from the third to fifth processing gas nozzles 33 to 35. In Condition 3, in the plasma annealing step S2, O2 gas was supplied from the second processing gas nozzle 32 without supplying O3 gas, and Ar gas was supplied without supplying NH3 gas from the third to fifth processing gas nozzles 33 to 35. In Condition 4, in the plasma annealing step S2, O2 gas was supplied from the second processing gas nozzle 32 without supplying O3 gas, and Ar gas and NH3 gas were supplied from the third to fifth processing gas nozzles 33 to 35. In Condition 5, in the plasma annealing step S2, O3 gas and O2 gas were supplied from the second processing gas nozzle 32, and Ar gas and NH3 gas were supplied from the third to fifth processing gas nozzles 33 to 35.

[0083] Conditions 6 to 7 are conditions where an annealing step without using plasma was performed instead of the plasma annealing step S2 after the above-described SiON film forming step S1. In Condition 6, in the annealing step, O3 gas and O2 gas were supplied from the second processing gas nozzle 32, and Ar gas was supplied without supplying NH3 gas from the third to fifth processing gas nozzles 33 to 35. In Condition 7, in the annealing step, O2 gas was supplied from the second processing gas nozzle 32 without supplying O3 gas, and Ar gas was supplied without supplying NH3 gas from the third to fifth processing gas nozzles 33 to 35.

[0084] The conditions of the SiON film formation step S1, the plasma annealing step S2, and the annealing step are as follows.

[0085] <SiON film formation step S1> Wafer temperature: 400 °C Pressure in the vacuum chamber 1: 1.8 Torr to 2.0 Torr (240 Pa to 267 Pa) RF power: 4000 W First processing gas nozzle 31: DIPAS gas Second processing gas nozzle 32: Mixed gas of O3 gas and O2 gas Third processing gas nozzles 33 to 35: Mixed gas of Ar gas and NH3 gas Rotation speed of the rotary table 2: 10 rpm <Plasma annealing step S2> Wafer temperature: 400 °C Pressure in the vacuum chamber 1: 1.8 Torr to 2.0 Torr (240 Pa to 267 Pa) RF power: 4000 W First processing gas nozzle 31: Not used (no supply of the first processing gas) Second processing gas nozzle 32: Mixed gas of O3 gas and O2 gas, O2 gas Third processing gas nozzles 33 to 35: Ar gas, mixed gas of Ar gas and NH3 gas Rotation speed of the rotary table 2: 10 rpm <Annealing step> Wafer temperature: 400 °C Pressure in the vacuum chamber 1: 1.8 Torr to 2.0 Torr (240 Pa to 267 Pa) RF power: 0 W First processing gas nozzle 31: Not used (no supply of the first processing gas) Second processing gas nozzle 32: Mixed gas of O3 gas and O2 gas, O2 gas Third processing gas nozzles 33 to 35: Ar gas Rotation speed of the rotary table 2: 10 rpm

[0086] Figure 14 is a diagram showing the measurement results of the refractive index of the SiON film under conditions 1 to 7.

[0087] As shown in FIG. 14, it can be seen that under conditions 2 and 3, the refractive index of the SiON film is lower than that under condition 1. That is, when Ar gas is supplied from the third processing gas nozzles 33 to 35 in the plasma annealing step S2, it can be seen that the refractive index of the SiON film becomes lower than when the plasma annealing step S2 is not performed. In particular, under condition 2, it can be seen that the refractive index of the SiON film is lower than that under condition 3. That is, when O3 gas is supplied from the second processing gas nozzle 32 in the plasma annealing step S2, it can be seen that the refractive index of the SiON film becomes lower than when O3 gas is not supplied from the second processing gas nozzle 32.

[0088] Also, as shown in FIG. 14, it can be seen that under condition 4, the refractive index of the SiON film is higher than that under condition 1. That is, when O3 gas is not supplied from the second processing gas nozzle 32 in the plasma annealing step S2 and Ar gas and NH3 gas are supplied from the third processing gas nozzles 33 to 35, it can be seen that the refractive index of the SiON film becomes higher than when the plasma annealing step S2 is not performed.

[0089] From these results, it was shown that the refractive index of the SiON film can be adjusted by switching whether or not NH3 gas is included in the gas supplied from the third processing gas nozzles 33 to 35 in the plasma annealing step S2.

[0090] Also, as shown in FIG. 14, it can be seen that under condition 5, the refractive index of the SiON film hardly changes with respect to condition 1. That is, when O3 gas is supplied from the second processing gas nozzle 32 and Ar gas and NH3 gas are supplied from the third processing gas nozzles 33 to 35 in the plasma annealing step S2, it can be seen that the refractive index of the SiON film hardly changes compared to when the plasma annealing step S2 is not performed. From this result, it is considered that in order to adjust the refractive index of the SiON film in the plasma annealing step S2, it is required not to supply O3 gas from the second processing gas nozzle 32.

[0091] Also, as shown in FIG. 14, it can be seen that under conditions 6 and 7, the refractive index of the SiON film does not change significantly with respect to condition 1. That is, when an annealing process is performed instead of the plasma annealing process S2, it can be seen that the refractive index of the SiON film does not change significantly compared to the case where the annealing process is not performed. From these results, it is considered that in order to adjust the refractive index of the SiON film, it is required to perform the plasma annealing process S2.

[0092] FIG. 15 is a diagram showing the concentrations of nitrogen and oxygen in the SiON film calculated based on FIG. 14. In FIG. 15, the diamond marks indicate the nitrogen (N) concentration, and the square marks indicate the oxygen (O) concentration.

[0093] As shown in FIG. 15, it can be seen that under conditions 2 and 3, the nitrogen concentration in the SiON film is lower than that under condition 1. That is, when Ar gas is supplied from the third processing gas nozzles 33 to 35 in the plasma annealing process S2, it can be seen that the nitrogen concentration in the SiON film becomes lower than that in the case where the plasma annealing process S2 is not performed. In particular, under condition 2, it can be seen that the nitrogen concentration in the SiON film is lower than that under condition 3. That is, when O3 gas is supplied from the second processing gas nozzle 32 in the plasma annealing process S2, it can be seen that the nitrogen concentration in the SiON film becomes lower than that in the case where O3 gas is not supplied from the second processing gas nozzle 32.

[0094] Also, as shown in FIG. 15, it can be seen that under condition 4, the nitrogen concentration in the SiON film is higher than that under condition 1. That is, when O3 gas is not supplied from the second processing gas nozzle 32 and Ar gas and NH3 gas are supplied from the third processing gas nozzles 33 to 35 in the plasma annealing process S2, it can be seen that the nitrogen concentration in the SiON film becomes higher than that in the case where the plasma annealing process S2 is not performed.

[0095] From these results, it was shown that the nitrogen concentration in the SiON film can be adjusted by switching whether or not to include NH3 gas in the gas supplied from the third processing gas nozzles 33 to 35 in the plasma annealing process S2.

[0096] Also, as shown in FIG. 15, it can be seen that under Condition 5, the nitrogen concentration of the SiON film hardly changes with respect to Condition 1. That is, when O3 gas is supplied from the second processing gas nozzle 32 and Ar gas and NH3 gas are supplied from the third processing gas nozzles 33 to 35 in the plasma annealing step S2, it can be seen that the nitrogen concentration in the SiON film hardly changes compared to the case where the plasma annealing step S2 is not performed. From this result, it is considered that in order to adjust the nitrogen concentration in the SiON film in the plasma annealing step S2, it is required not to supply O3 gas from the second processing gas nozzle 32.

[0097] Also, as shown in FIG. 15, it can be seen that under Conditions 6 and 7, the nitrogen concentration in the SiON film hardly changes with respect to Condition 1. That is, when an annealing step is performed instead of the plasma annealing step S2, it can be seen that the nitrogen concentration in the SiON film hardly changes compared to the case where the annealing step is not performed. From this result, it is considered that in order to adjust the nitrogen concentration in the SiON film, it is required to perform the plasma annealing step S2.

[0098] FIG. 16 is a diagram showing the measurement results of the film thickness of the SiON film under Conditions 1 to 7.

[0099] As shown in FIG. 16, it can be seen that the film thickness of the SiON film is almost the same under any of Conditions 1 to 7. From this result, it can be said that the presence or absence of the plasma annealing step S2, the presence or absence of the annealing step, and the difference in the gas supplied from the third processing gas nozzles 33 to 35 in the plasma annealing step S2 hardly affect the film thickness of the SiON film. Also, although not shown in the figure, the in-plane uniformity of the film thickness of the SiON film was almost the same under any of Conditions 1 to 7. From this result, it can be said that the presence or absence of the plasma annealing step S2, the presence or absence of the annealing step, and the difference in the gas supplied from the third processing gas nozzles 33 to 35 in the plasma annealing step S2 hardly affect the in-plane uniformity of the film thickness of the SiON film.

[0100] The embodiments disclosed herein should be considered illustrative in all respects and not restrictive. The above embodiments may be omitted, substituted, or changed in various forms without departing from the scope and spirit of the appended claims.

[0101] In the above embodiment, a semi-batch type apparatus has been described in which a film forming apparatus revolves a plurality of substrates arranged on a rotating table in a processing chamber by the rotating table and passes through a plurality of processing regions in order to perform processing on the substrates. However, the present disclosure is not limited thereto. For example, the film forming apparatus may be a batch type apparatus that performs processing on a plurality of substrates at once. Further, for example, the film forming apparatus may be a single wafer type apparatus that processes substrates one by one.

[0102] In the above embodiment, the case where the first processing gas is a DIPAS gas has been described. However, the present disclosure is not limited thereto. The first processing gas may be any gas containing a silicon-containing gas, and may contain an inert gas such as Ar gas in addition to the silicon-containing gas. As the silicon-containing gas, for example, an aminosilane-based gas, a silicon hydride gas, a halogen-containing silicon gas, and combinations thereof can be used. Examples of the aminosilane-based gas include DIPAS (diisopropylaminosilane) gas, 3DMAS (trisdimethylaminosilane) gas, and BTBAS (bis-t-butylaminosilane) gas. Examples of the silicon hydride gas include SiH4 (MS) gas, Si2H6 (DS) gas, Si3H8 gas, and Si4H 10 gas. Examples of the halogen-containing silicon gas include fluorine-containing silicon gases such as SiF4 gas, SiHF3 gas, SiH2F2 gas, and SiH3F gas, chlorine-containing silicon gases such as SiCl4 gas, SiHCl3 gas, SiH2Cl2 (DCS) gas, SiH3Cl gas, and Si2Cl6 gas, and bromine-containing silicon gases such as SiBr4 gas, SiHBr3 gas, SiH2Br2 gas, and SiH3Br gas.

[0103] In the above-described embodiment, the case where the second processing gas is a mixed gas of O3 gas and O2 gas has been described, but the present disclosure is not limited thereto. The second processing gas may be any gas containing an oxidizing gas, and may contain an inert gas such as Ar gas in addition to the oxidizing gas. As the oxidizing gas, for example, O2 gas, O3 gas, H2O gas, NO2 gas, and combinations thereof can be used.

[0104] In the above-described embodiment, the case where the third processing gas is a mixed gas of NH3 gas and Ar gas has been described, but the present disclosure is not limited thereto. The third processing gas may be any gas containing a nitriding gas. As the nitriding gas, for example, ammonia (NH3) gas, diazene (N2H2) gas, hydrazine (N2H4) gas, monomethylhydrazine (CH3(NH)NH2) gas, and combinations thereof can be used.

[0105] In the above-described embodiment, the case where the plasma generation gas is Ar gas or a mixed gas of Ar gas and NH3 gas has been described, but the present disclosure is not limited thereto. For example, instead of NH3 gas, another nitriding gas described above can be used.

[0106] In the above-described embodiment, the case of forming a SiON film has been described, but the present disclosure is not limited thereto. For example, the film formed by the film-forming method of the embodiment may be any film containing silicon (Si), oxygen (O), and nitrogen (N), and may contain other elements.

Description of Reference Numerals

[0107] 1 Vacuum chamber 2 Rotating table 31 First processing gas nozzle 32 Second processing gas nozzle 33 - 35 Third processing gas nozzles 120 Control unit W Wafer

Claims

1. (a) forming a film containing silicon (Si), oxygen (O) and nitrogen (N) on a substrate; (b) exposing the substrate on which the film is formed to plasma generated from a plasma generation gas containing Ar gas, and adjusting the nitrogen concentration in the film by switching whether or not to include a nitriding gas in the plasma generation gas; having The step (a) includes: supplying a first processing gas containing a silicon-containing gas to the substrate; supplying a second processing gas containing an oxidizing gas to the substrate; supplying a third processing gas containing a nitriding gas to the substrate; including repeating a cycle including a film forming method.

2. The step (b) includes lowering the nitrogen concentration in the film by not including a nitriding gas in the plasma generation gas. The film forming method according to Claim 1.

3. The step (b) includes increasing the nitrogen concentration in the film by including a nitriding gas in the plasma generation gas. The film forming method according to Claim 1.

4. Repeating the step (a) and the step (b) alternately. The film forming method according to any one of Claims 1 to 3.

5. The nitriding gas contained in the plasma generation gas is the same as the nitriding gas contained in the third processing gas. The film forming method according to any one of Claims 1 to 4.

6. The substrate is disposed along the circumferential direction on the upper surface of a rotating table provided in a vacuum chamber. Above the rotating table in the vacuum chamber, along the rotation direction of the rotating table, a first processing gas supply unit capable of supplying the first processing gas, a second processing gas supply unit capable of supplying the second processing gas, and a third processing gas supply unit capable of supplying plasma generated from the third processing gas or the plasma generation gas are provided. The step (a) is performed by supplying the first processing gas from the first processing gas supply unit, supplying the second processing gas from the second processing gas supply unit, supplying the third processing gas from the third processing gas supply unit, and generating plasma from the third processing gas while rotating the rotating table. In the step (b), without supplying the first processing gas from the first processing gas supply unit, the plasma generation gas is supplied from the third processing gas supply unit, and the plasma is generated from the plasma generation gas, and the rotating table is rotated to perform the step. The film forming method according to any one of claims 1 to 5.

7. The step (b) is performed in a state where the second processing gas is supplied from the second processing gas supply unit. The film forming method according to claim 6.

8. A rotating table provided in a vacuum chamber and having a plurality of substrates placed on an upper surface along a circumferential direction. A first processing gas supply unit provided above the rotating table in the vacuum chamber along the rotation direction of the rotating table and capable of supplying a first processing gas containing a silicon-containing gas, a second processing gas supply unit capable of supplying a second processing gas containing an oxidation gas, and a third processing gas supply unit capable of supplying a plasma generated from a third processing gas containing a nitriding gas or a plasma generation gas containing an Ar gas. A control unit. Comprising: The control unit: A step of forming a film containing silicon (Si), oxygen (O), and nitrogen (N) on the substrate by supplying the first processing gas from the first processing gas supply unit, supplying the second processing gas from the second processing gas supply unit, supplying the third processing gas from the third processing gas supply unit, and generating plasma from the third processing gas and rotating the rotating table. A step of exposing the substrate on which the film is formed to the plasma generated from the plasma generation gas by rotating the rotating table in a state where the plasma generation gas is supplied from the third processing gas supply unit without supplying the first processing gas from the first processing gas supply unit and plasma is generated from the plasma generation gas, and adjusting the nitrogen concentration in the film by switching whether or not to include a nitriding gas in the plasma generation gas. The rotating table, the first processing gas supply unit, the second processing gas supply unit, and the third processing gas supply unit are configured to be controlled so as to execute the above steps. A film forming apparatus.

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