Film deposition method and film deposition apparatus

Abstract

To provide a technique capable of suppressing an overhang.SOLUTION: A deposition method of forming a film on a front surface of a substrate having a convex part on the front surface, includes: (a) supplying an original gas onto the front surface of the substrate, and making the front surface of the substrate adsorb the original gas; and (b) supplying a reaction gas onto the front surface of the substrate to form the film on the front surface of the substrate by a thermal reaction of the original gas adsorbed to the front surface of the substrate and the reaction gas. The substrate is arranged along a peripheral direction on the front surface of a rotational table provided in a vacuum container. In the vacuum container, an adsorption region where the (a) is executed and a reaction region where the (b) is executed are provided along the peripheral direction of the rotational table above the rotational table. In a state where the original gas is supplied from an original gas supply part to the adsorption region and the reaction gas is supplied from a reaction gas supply part to the reaction region, the rotational table is rotated, and the (a) and the (b) are repeatedly executed to the substrate. At least one of the original gas supply part and the reaction gas supply part supplies the gas at an angle with respect to a vertically downward.SELECTED DRAWING: Figure 4

Description

Technical Field

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

Background Art

[0002] As an example of a film forming apparatus that performs the atomic layer deposition (ALD) method, a film forming apparatus including a rotating table is known (see, for example, Patent Documents 1 and 2). The rotating table type film forming apparatus has a rotating table that is rotatably provided in a vacuum chamber. On the surface of the rotating table, substrates are arranged along the circumferential direction. In the vacuum chamber, a supply region for a raw material gas, a supply region for a reaction gas, and a separation region that separates these supply regions are provided above the rotating table.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure provides a technique capable of suppressing overhang.

Means for Solving the Problems

[0005] A film-forming method according to one aspect of the present disclosure is a film-forming method for forming a film on the surface of a substrate having protrusions on its surface, comprising: (a) a step of supplying a raw material gas onto the surface of the substrate and adsorbing the raw material gas onto the surface of the substrate; and (b) a step of supplying a reaction gas onto the surface of the substrate and forming a film on the surface of the substrate by a thermal reaction between the raw material gas adsorbed on the surface of the substrate and the reaction gas, wherein the substrate is arranged circumferentially on the surface of a rotating table provided in a vacuum chamber, and the vacuum chamber is provided with an adsorption region for performing step (a) and a reaction region for performing step (b) above the rotating table and along the circumferential direction of the rotating table, and the raw material gas is supplied to the adsorption region from a raw material gas supply unit and the reaction gas is supplied to the reaction region from a reaction gas supply unit, and the rotating table is rotated so that steps (a) and (b) are repeatedly performed on the substrate, and the raw material gas supply The department , relative to the vertically downward direction The first is located downstream in the rotational direction of the aforementioned rotary table. The gas is supplied at an angle. [Effects of the Invention]

[0006] According to this disclosure, overhang can be suppressed. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a schematic cross-sectional view showing a film deposition apparatus according to an embodiment. [Figure 2] Figure 2 is a schematic perspective view showing the configuration inside the vacuum chamber of the film deposition apparatus shown in Figure 1. [Figure 3] Figure 3 is a schematic plan view showing the configuration inside the vacuum chamber of the film deposition apparatus shown in Figure 1. [Figure 4] Figure 4 is a schematic cross-sectional view of the vacuum vessel along the concentric circles of the rotating table of the film deposition apparatus shown in Figure 1. [Figure 5] Figure 5 is another schematic cross-sectional view of the film deposition apparatus shown in Figure 1. [Figure 6] Figure 6 is a schematic cross-sectional view showing a plasma generator. [Figure 7]Figure 7 is another schematic cross-sectional view showing the plasma generator. [Figure 8] Figure 8 is a schematic top view showing the plasma generator. [Figure 9] Figure 9 is a diagram illustrating the film formed on the surface of the substrate. [Figure 10] Figure 10 is a cross-sectional view (1) showing the film deposition method according to the embodiment. [Figure 11] Figure 11 is a cross-sectional view (2) showing the film deposition method according to the embodiment. [Figure 12] Figure 12 is a cross-sectional view (3) showing the film deposition method according to the embodiment. [Figure 13] Figure 13 is a cross-sectional view (4) showing the film deposition method according to the embodiment. [Figure 14] Figure 14 is a cross-sectional view (5) showing the film deposition method according to the embodiment. [Figure 15] Figure 15 is a cross-sectional view (6) showing the film deposition method according to the embodiment. [Figure 16] Figure 16 shows the wet etching rate and refractive index characteristics of a titanium oxide film formed on the surface of a substrate. [Modes for carrying out the invention]

[0008] Hereinafter, exemplary embodiments of the present disclosure, not limited to those described herein, will be described with reference to the attached drawings. In all attached drawings, identical or corresponding members or components are denoted by the same or corresponding reference numerals, and redundant descriptions are omitted.

[0009] [Film forming equipment] A suitable film deposition apparatus for carrying out the film deposition method according to the embodiment will be described. The film deposition method according to the embodiment can be carried out with various film deposition apparatuses as long as the type of gas supplied to the substrate can be switched at high speed, and the form of the film deposition apparatus is not limited. Here, an example of a film deposition apparatus capable of rapidly switching the type of gas supplied to the substrate will be described.

[0010] Referring to FIGS. 1 to 3, the film forming apparatus includes a flat vacuum chamber 1 having a substantially circular planar shape, and a rotary table 2 provided in the vacuum chamber 1 and having a rotation center at the center of the vacuum chamber 1. The vacuum chamber 1 is a processing chamber for performing a film forming process on the surface of a substrate W accommodated therein. The substrate W is, for example, a semiconductor wafer. The vacuum chamber 1 has a container body 12 having a bottomed cylindrical shape, and a top plate 11 that is detachably and airtightly disposed on the upper surface of the container body 12 via a seal member 13 (FIG. 1) such as an O-ring.

[0011] The rotary table 2 is fixed to a cylindrical core portion 21 at the center. The core portion 21 is fixed to the upper end of a rotary shaft 22 extending in the vertical direction. The rotary shaft 22 penetrates the bottom 14 of the vacuum chamber 1, and the lower end is attached to a drive unit 23 that rotates the rotary shaft 22 (FIG. 1) around the vertical axis. The rotary shaft 22 and the drive unit 23 are housed in a cylindrical case body 20 having an open upper surface. The case body 20 has a flange portion provided on its upper surface airtightly attached to the lower surface of the bottom 14 of the vacuum chamber 1, and an airtight state between the internal atmosphere of the case body 20 and the external atmosphere is maintained.

[0012] As shown in FIGS. 2 and 3, a circular recess 24 for placing a plurality (five in the illustrated example) of substrates W along the rotation direction (circumferential direction) is provided on the surface portion of the rotary table 2. In FIG. 3, for convenience, only one recess 24 is shown with the substrate W. The recess 24 has an inner diameter slightly larger than the diameter of the substrate W, for example, 4 mm larger, and a depth substantially equal to the thickness of the substrate W. Therefore, when the substrate W is accommodated in the recess 24, the surface of the substrate W and the surface of the rotary table 2 (the region where the substrate W is not placed) are at the same height. Through holes (none of which are shown) through which, for example, three lifting pins for supporting the back surface of the substrate W and raising and lowering the substrate W penetrate are formed in the bottom surface of the recess 24.

[0013] Figures 2 and 3 are diagrams illustrating the internal structure of the vacuum vessel 1, and for the sake of clarity, the top plate 11 is not shown. As shown in Figures 2 and 3, above the rotary table 2, the raw material gas nozzle 31, reaction gas nozzle 32, reformed gas nozzle 33, and separation gas nozzles 41 and 42 are arranged at intervals from each other in the circumferential direction of the vacuum vessel 1 (the direction of rotation of the rotary table 2 (arrow A in Figure 3)). In the illustrated example, the separation gas nozzle 41, raw material gas nozzle 31, separation gas nozzle 42, reaction gas nozzle 32, and reformed gas nozzle 33 are arranged in this order along the direction of rotation of the rotary table 2. Each nozzle 31, 32, 33, 41, and 42 is made of, for example, quartz. The base end of each nozzle 31, 32, 33, 41, and 42, which is the gas introduction port 31a, 32a, 33a, 41a, and 42a (Figure 3), is fixed to the outer circumferential wall of the vessel body 12. As a result, each nozzle 31, 32, 33, 41, and 42 is introduced into the vacuum vessel 1 from the outer wall of the vacuum vessel 1 and mounted so as to extend horizontally to the rotary table 2 along the radial direction of the vessel body 12.

[0014] The raw material gas nozzle 31 is an example of a raw material gas supply unit. The raw material gas nozzle 31 is connected to the raw material gas supply source 130 via piping 110 and a flow controller 120, etc. The raw material gas nozzle 31 has a plurality of discharge holes 31h (Figure 4) arranged at predetermined intervals along the length of the raw material gas nozzle 31. The predetermined interval may be, for example, 10 mm. The area below the raw material gas nozzle 31 becomes an adsorption area P1 for adsorbing the raw material gas.

[0015] Each discharge hole 31h opens at a first angle θ1, for example, towards the downstream side in the rotational direction of the rotary table 2 relative to the vertically downward direction. The raw material gas nozzle 31 supplies the raw material gas from each discharge hole 31h at a first angle θ1 relative to the vertically downward direction. In this case, when forming a film on the surface of the substrate W having protrusions on its surface, the raw material gas supplied from each discharge hole 31h can easily reach the upper part of the protrusions, but not so easily reach the lower part. Therefore, the amount of raw material gas adsorbed is greater at the upper part of the protrusions than at the lower part. Also, the raw material gas supplied from each discharge hole 31h is more easily adsorbed on the upper surface of the protrusions than on the side surfaces.

[0016] The first angle θ1 is an angle other than 0°. The first angle θ1 is preferably 60° or more and 80° or less, for example, 70°. Each discharge hole 31h may be opened with the first angle θ1 facing upstream in the rotational direction of the rotary table 2 relative to the vertically downward direction.

[0017] The raw material gas is, for example, an organometallic gas or an organometallic gas. The organometallic gas may be, for example, an organometallic gas used for forming high-dielectric constant (High-k) films. The organometallic gas may be a gas containing various organometallics, and for example, when forming a titanium oxide (TiO2) film, it may be a gas containing organoaminotitanium such as TDMAT (tetrakisdimethylaminotitanium) gas. The organometallic gas may be an organosilane gas, such as an organoaminosilane gas such as 3DMASi.

[0018] The reaction gas nozzle 32 is an example of a reaction gas supply unit. The reaction gas nozzle 32 is connected to the oxidizing gas supply source 131 via piping 111 and a flow controller 121, etc. The reaction gas nozzle 32 has a plurality of discharge holes 32h (Figure 4) arranged at predetermined intervals along the length of the reaction gas nozzle 32. The predetermined interval may be, for example, 10 mm. The region below the reaction gas nozzle 32 is an oxidation region P2 in which an oxidizing gas is supplied to oxidize the raw material gas adsorbed on the substrate W in the adsorption region P1, and a molecular layer of oxides of organometallic or organometallic semi-metallic contained in the raw material gas is generated as a reaction product by thermal oxidation. The oxidation region P2 is an example of a reaction region.

[0019] Each discharge hole 32h opens at a second angle θ2, for example, toward the downstream side in the rotational direction of the rotary table 2 relative to the vertically downward direction. The reaction gas nozzle 32 supplies oxidizing gas from each discharge hole 32h at a second angle θ2 relative to the vertically downward direction. In this case, when forming a film on the surface of the substrate W having protrusions on its surface, the oxidizing gas supplied from each discharge hole 32h easily reaches the upper part of the protrusions but does not easily reach the lower part of the protrusions. Therefore, as shown in Figure 9, the thickness of the film formed on the upper part of the protrusions, for example, on the upper surface of the protrusions, and the thickness of the film formed on the upper side of the protrusions, T2 and T3 respectively, are thicker than the thickness T1 of the film formed on the lower part of the protrusions, for example, on the bottom surface between adjacent protrusions. This makes it possible to form a helmet-shaped film that covers the upper surface and upper side of the protrusions. In addition, the oxidizing gas supplied from each discharge hole 32h reacts more easily with the raw material gas on the upper surface of the protrusions than on the side surfaces. Therefore, as shown in Figure 9, the thickness T2 of the film formed on the upper surface of the protrusions tends to be thicker than the thickness T3 of the film formed on the side surfaces of the protrusions. As a result, it is possible to form a membrane with a helmet shape that has suppressed overhang (low overhang ratio). The overhang ratio is expressed as the ratio (T3 / T2) of the thickness T2 of the membrane formed on the upper surface of the convex part to the thickness T3 of the membrane formed on the side surface of the convex part, as shown in Figure 9.

[0020] The second angle θ2 is an angle other than 0°. The second angle θ2 is preferably 80° or more and 100° or less, for example 90°. When the second angle θ2 is 90°, the reaction gas nozzle 32 supplies oxidizing gas from each discharge hole 32h parallel to the surface of the rotary table 2. Each discharge hole 32h may open with the second angle θ2 facing upstream in the rotational direction of the rotary table 2 relative to the vertically downward direction.

[0021] As the oxidizing gas, any oxidizing gas that can react with the supplied organometallic gas to produce organometallic oxides can be used. For example, when oxidizing organometallic gases by thermal oxidation, water vapor (H2O), hydrogen peroxide (H2O2), oxygen (O2), and ozone (O3) gas can be selected as the oxidizing gas.

[0022] The reaction gas nozzle 32 may be connected to a source of nitriding gas. In this case, the region below the reaction gas nozzle 32 becomes a nitriding region where a nitriding gas is supplied to nitrid the raw material gas adsorbed on the substrate W in the adsorption region P1, and a molecular layer of nitrides of organometallic or organometallic semi-nitrides contained in the raw material gas is produced as a reaction product by thermal nitriding. The nitriding region is an example of a reaction region. Various nitriding gases can be used as the nitriding gas, as long as they can react with the supplied organometallic gas to produce organometallic nitrides. For example, when nitriding an organometallic gas by thermal nitriding, ammonia (NH3) gas is selected as the nitriding gas.

[0023] The reforming gas nozzle 33 is connected to a noble gas supply source 132 and an additive gas supply source 133 via piping 112 and a flow controller 122. The region below the reforming gas nozzle 33 becomes a reforming region P3 where plasma treatment (reforming treatment) is performed by supplying plasma-conjugated noble gas and additive gas to organometallic oxides or organometallic semi-oxides (protective films) generated by thermal oxidation in the oxidation region P2. Argon (Ar) gas and helium (He) gas, which are suitable for plasma formation, are selected as noble gases. Oxygen gas or hydrogen (H2) gas, etc., are selected as additive gases.

[0024] The modification region P3 is optional. Plasma modification is optional, and the system may be configured to perform only a thermal reaction (thermal oxidation or thermal nitriding) in the oxidation region P2 or the nitriding region. In this case, the plasma generator 80 and the modification gas nozzle 33 are not required. If the modification region P3 is provided, the plasma generator 80 and the modification gas nozzle 33 are provided. In Figure 3, the plasma generator 80 is shown simplified with a dashed line. Details of the modification gas nozzle 33 and the plasma generator 80 will be described later.

[0025] Both separation gas nozzles 41 and 42 are connected to a separation gas supply source (not shown) via piping and flow control valves (not shown). Nitrogen (N2) gas is used as the separation gas. Noble gases such as helium gas or argon gas may also be used as the separation gas.

[0026] The illustrated example shows a case where there is one raw material gas nozzle 31, but for example, two or more raw material gas nozzles 31 may be provided spaced apart in the rotational direction of the rotary table 2.

[0027] Referring to Figures 2 and 3, two convex portions 4 are provided inside the vacuum vessel 1. The convex portions 4, together with the separation gas nozzles 41 and 42, constitute the separation region D. For this reason, as will be described later, they are attached to the underside of the top plate 11 so as to protrude toward the rotary table 2. The convex portions 4 have a fan-shaped planar form with their tops cut in an arc shape. The inner arc of the convex portion 4 is connected to the protruding portion 5 (described later), and the outer arc is positioned to follow the inner circumferential surface of the container body 12 of the vacuum vessel 1.

[0028] Figure 4 shows a cross-section of the vacuum vessel 1 along the concentric circles of the rotary table 2 from the raw material gas nozzle 31 to the reaction gas nozzle 32. As shown in the figure, a convex portion 4 is attached to the underside of the top plate 11. Therefore, inside the vacuum vessel 1, there is a flat, low first ceiling surface 44 which is the underside of the convex portion 4, and second ceiling surfaces 45 which are located on both sides of the first ceiling surface 44 in the circumferential direction and are higher than the first ceiling surface 44. The first ceiling surface 44 has a fan-shaped planar shape with its top cut in an arc shape. As shown in the figure, a groove 43 is formed in the center of the convex portion 4 so as to extend radially. The separation gas nozzle 42 is housed in the groove 43. Similarly, a groove 43 is formed in the other convex portion 4, and the separation gas nozzle 41 is housed there. The raw material gas nozzle 31 and the reaction gas nozzle 32 are provided in the space below the second ceiling surface 45. The raw material gas nozzle 31 and the reaction gas nozzle 32 are provided in the vicinity of the substrate W, spaced apart from the second ceiling surface 45. As shown in Figure 4, the raw material gas nozzle 31 is provided in the space 481 on the right side below the second ceiling surface 45, and the reaction gas nozzle 32 is provided in the space 482 on the left side below the second ceiling surface 45.

[0029] The separation gas nozzle 42 has a plurality of discharge holes 42h (Figure 4) that open toward the rotary table 2, arranged at predetermined intervals along the length of the separation gas nozzle 42. The predetermined interval may be, for example, 10 mm. Similarly to the separation gas nozzle 42, the separation gas nozzle 41 also has a plurality of discharge holes (not shown) that open toward the rotary table 2, arranged at predetermined intervals along the length of the separation gas nozzle 41. The predetermined interval may be, for example, 10 mm.

[0030] The first ceiling surface 44 forms a narrow separation space H relative to the rotating table 2. When nitrogen gas is supplied from the discharge hole 42h of the separation gas nozzle 42, the nitrogen gas flows through the separation space H toward spaces 481 and 482. At this time, since the volume of the separation space H is smaller than the volume of spaces 481 and 482, the nitrogen gas can raise the pressure in the separation space H to a higher level than the pressure in spaces 481 and 482. That is, a high-pressure separation space H is formed between spaces 481 and 482. The nitrogen gas flowing out of the separation space H into spaces 481 and 482 acts as a counterflow for the raw material gas from the adsorption region P1 and the oxidizing gas from the oxidation region P2. As a result, the raw material gas from the adsorption region P1 and the oxidizing gas from the oxidation region P2 are separated by the separation space H. Therefore, mixing and reaction between the raw material gas and the oxidizing gas within the vacuum container 1 is suppressed.

[0031] The height h1 of the first ceiling surface 44 relative to the top surface of the rotary table 2 is set to a height suitable for making the pressure in the separation space H higher than the pressures in spaces 481 and 482, taking into consideration the pressure inside the vacuum chamber 1 during film formation, the rotation speed of the rotary table 2, and the amount of separation gas (nitrogen gas) supplied.

[0032] A projection 5 (Figures 2 and 3) is provided on the underside of the top plate 11, surrounding the outer circumference of the core portion 21 that fixes the rotating table 2. The projection 5 is continuous with the part of the convex portion 4 that is on the rotation center side, and its underside is formed at the same height as the first ceiling surface 44.

[0033] Figure 1, which was previously referenced, is a cross-sectional view along the line I-I' in Figure 3, showing the region where the second ceiling surface 45 is provided. On the other hand, Figure 5 is a cross-sectional view showing the region where the first ceiling surface 44 is provided. As shown in Figure 5, a bent portion 46 is formed on the periphery of the fan-shaped convex portion 4 (the outer edge side of the vacuum vessel 1), bending in an L-shape so as to face the outer end surface of the rotary table 2. Similar to the convex portion 4, the bent portion 46 suppresses the intrusion of reaction gases from both sides of the separation region D and suppresses the mixing of the two reaction gases. The convex portion 4 is provided on the top plate 11, and since the top plate 11 can be removed from the container body 12, there is a small gap between the outer circumferential surface of the bent portion 46 and the container body 12. The gap between the inner circumferential surface of the bent portion 46 and the outer end surface of the rotary table 2, and the gap between the outer circumferential surface of the bent portion 46 and the container body 12 are set to dimensions similar to, for example, the height of the first ceiling surface 44 relative to the top surface of the rotary table 2.

[0034] In the separation region D, the inner circumferential wall of the container body 12 is formed as a vertical surface close to the outer circumferential surface of the bent portion 46, as shown in Figure 4. In areas other than the separation region D, the inner circumferential wall of the container body 12 is recessed outward from the portion facing the outer end surface of the rotary table 2, for example, to the bottom 14, as shown in Figure 1. For the sake of explanation, the recessed portion having a roughly rectangular cross-sectional shape will be referred to as the exhaust region. Specifically, the exhaust region communicating with the adsorption region P1 will be referred to as the first exhaust region E1, and the region communicating with the oxidation region P2 and the modification region P3 will be referred to as the second exhaust region E2. At the bottom of the first exhaust region E1 and the second exhaust region E2, a first exhaust port 610 and a second exhaust port 620 are formed, respectively, as shown in Figures 1 to 3. The first exhaust port 610 and the second exhaust port 620 are each connected to a vacuum exhaust means, such as a vacuum pump 640, via an exhaust pipe 630, as shown in Figure 1. A pressure controller 650 is installed between the vacuum pump 640 and the exhaust pipe 630.

[0035] A heater unit 7 is provided in the space between the rotary table 2 and the bottom 14 of the vacuum vessel 1, as shown in Figures 1 and 4. The heater unit 7 heats the substrate W on the rotary table 2 to a temperature (e.g., 150°C) determined by the process recipe via the rotary table 2. A ring-shaped cover member 71 is provided on the lower side near the periphery of the rotary table 2 (Figure 5). This separates the atmosphere from the space above the rotary table 2 to the exhaust regions E1 and E2 from the atmosphere where the heater unit 7 is located, thereby suppressing the intrusion of gas into the lower region of the rotary table 2. The cover member 71 comprises an inner member 71a provided so as to face the outer edge of the rotary table 2 and the outer circumference beyond the outer edge from below, and an outer member 71b provided between the inner member 71a and the inner wall surface of the vacuum vessel 1. The outer member 71b is provided below the bent portion 46 formed on the outer edge of the convex portion 4 in the separation region D, and close to the bent portion 46. The inner member 71a surrounds the heater unit 7 all around, below the outer edge of the rotary table 2 (and slightly below the outer edge).

[0036] The bottom portion 14, closer to the center of rotation than the space where the heater unit 7 is located, protrudes upward to form a projection 12a, approaching the core portion 21 near the center of the lower surface of the rotary table 2. There is a narrow space between the projection 12a and the core portion 21, and the gap between the inner circumferential surface of the through-hole for the rotating shaft 22 that penetrates the bottom portion 14 and the rotating shaft 22 is also narrow. These narrow spaces communicate with the case body 20. The case body 20 is provided with a purge gas supply pipe 72 for supplying nitrogen gas, which is a purge gas, into these narrow spaces for purging. The bottom portion 14 of the vacuum vessel 1 is provided with a plurality of purge gas supply pipes 73 at predetermined angular intervals in the circumferential direction below the heater unit 7 for purging the space where the heater unit 7 is located (Figure 5 shows one purge gas supply pipe 73). Between the heater unit 7 and the rotary table 2, a cover member 7a is provided to cover the area from the inner circumferential wall of the outer member 71b (the upper surface of the inner member 71a) to the upper end of the protrusion 12a in the circumferential direction, in order to prevent gas from entering the area where the heater unit 7 is installed. The cover member 7a is made of, for example, quartz.

[0037] A separation gas supply pipe 51 is connected to the center of the top plate 11 of the vacuum vessel 1. The separation gas supply pipe 51 supplies nitrogen gas, which is the separation gas, to the space 52 between the top plate 11 and the core portion 21. The separation gas supplied to space 52 is discharged towards the periphery along the surface of the substrate mounting area side of the rotary table 2 through the narrow space 50 between the protrusion 5 and the rotary table 2. Space 50 can be maintained at a higher pressure than spaces 481 and 482 by the separation gas. As a result, space 50 prevents the mixing of the organometallic gas supplied to the adsorption region P1 and the oxidizing gas supplied to the oxidation region P2 through the central region C. That is, space 50 (or central region C) functions similarly to the separation space H (or separation region D).

[0038] As shown in Figures 2 and 3, a transfer port 15 is formed in the side wall of the vacuum chamber 1 for transferring the substrate W between the external transfer arm 10 and the rotary table 2. The transfer port 15 is opened and closed by a gate valve (not shown). The recess 24, which is the substrate placement area on the rotary table 2, is where the transfer of the substrate W between the transfer arm 10 takes place, facing the transfer port 15. For this reason, a lifting pin and its lifting mechanism (neither shown) are provided on the lower side of the rotary table 2 at the location corresponding to the transfer position, to lift the substrate W from the back side by passing through the recess 24.

[0039] Next, the plasma generator 80 will be described with reference to Figures 6 to 8. Figure 6 is a schematic cross-sectional view of the plasma generator 80 along the radial direction of the rotary table 2, Figure 7 is a schematic cross-sectional view of the plasma generator 80 along the direction perpendicular to the radial direction of the rotary table 2, and Figure 8 is a schematic top view of the plasma generator 80. For ease of illustration, some components are simplified in these figures.

[0040] Referring to Figure 6, the plasma generator 80 comprises a frame member 81, a Faraday shielding plate 82, an insulating plate 83, and an antenna 85.

[0041] The frame member 81 is made of a high-frequency transparent material. The frame member 81 has a recess that is indented from the top surface. The frame member 81 is fitted into an opening 11a formed in the top plate 11. The Faraday shielding plate 82 is housed in the recess of the frame member 81. The Faraday shielding plate 82 has a roughly box-like shape with an open top. The insulating plate 83 is placed on the bottom surface of the Faraday shielding plate 82. The antenna 85 is supported above the insulating plate 83. The antenna 85 has a coil shape with a roughly octagonal top surface.

[0042] The opening 11a of the top plate 11 has multiple stepped sections. A groove is formed around the entire circumference of one of the stepped sections, and a sealing member 81a, such as an O-ring, is fitted into this groove. The frame member 81 has multiple stepped sections corresponding to the stepped sections of the opening 11a. When the frame member 81 is fitted into the opening 11a, the back surface of one of the stepped sections contacts the sealing member 81a fitted into the groove of the opening 11a. This maintains airtightness between the top plate 11 and the frame member 81. As shown in Figure 6, a pressing member 81c is provided along the outer circumference of the frame member 81 fitted into the opening 11a of the top plate 11. This presses the frame member 81 downward against the top plate 11. Therefore, airtightness between the top plate 11 and the frame member 81 is maintained more reliably.

[0043] The lower surface of the frame member 81 faces the rotary table 2 inside the vacuum chamber 1, and a projection 81b is provided on the outer circumference of its lower surface, projecting downward (towards the rotary table 2) along its entire circumference. The lower surface of the projection 81b is close to the surface of the rotary table 2, and the projection 81b, the surface of the rotary table 2, and the lower surface of the frame member 81 define a space above the rotary table 2 (hereinafter referred to as the modification region P3). The distance between the lower surface of the projection 81b and the surface of the rotary table 2 may be approximately the same as the height h1 of the first ceiling surface 44 relative to the upper surface of the rotary table 2 in the separation space H (Figure 4).

[0044] A reforming gas nozzle 33 extends through the projection 81b into the reforming region P3. As shown in Figure 6, a noble gas supply source 132, which is filled with noble gases such as argon or helium, is connected to the reforming gas nozzle 33 via piping 112 through a flow controller 122. As shown in Figure 6, an additive gas supply source 133, which is filled with additive gases such as oxygen or hydrogen, is connected to the reforming gas nozzle 33 via piping 112 through a flow controller 123. That is, the noble gas, whose flow rate is controlled by the flow controller 122, and the additive gas, whose flow rate is controlled by the flow controller 123, are both mixed at a predetermined flow rate, and the mixed gas is plasma-generated by the plasma generator 80 and supplied to the reforming region P3.

[0045] The reformed gas nozzle 33 has a plurality of discharge holes 33h arranged at predetermined intervals along the length of the reformed gas nozzle 33. The predetermined interval may be, for example, 10 mm. The reformed gas nozzle 33 discharges the above-mentioned mixed gas from the discharge holes 33h. As shown in Figure 7, the discharge holes 33h are inclined from a direction perpendicular to the rotary table 2 toward the upstream side in the direction of rotation of the rotary table 2. Therefore, the gas supplied from the reformed gas nozzle 33 is discharged in the opposite direction to the direction of rotation of the rotary table 2, specifically toward the gap between the lower surface of the projection 81b and the surface of the rotary table 2. This prevents reaction gases and separation gases from flowing into the reformed region P3 from the space below the second ceiling surface 45, which is located upstream of the plasma generator 80 along the direction of rotation of the rotary table 2. Furthermore, as described above, since the projection 81b formed along the outer circumference of the lower surface of the frame member 81 is close to the surface of the rotary table 2, the pressure in the reforming region P3 can be easily maintained at a high level by the gas from the reforming gas nozzle 33. This also prevents reaction gases and separation gases from flowing into the reforming region P3.

[0046] Thus, the frame member 81 plays a role in separating the modification region P3 from the oxidation region P2. Therefore, the film deposition apparatus according to this embodiment does not necessarily have to include the entire plasma generator 80, but it is assumed to include the frame member 81 in order to partition the modification region P3 from the oxidation region P2 and prevent the inclusion of oxidizing gas.

[0047] The Faraday shielding plate 82 is made of a conductive material such as metal and is grounded, although this is not shown in the figure. As shown in Figure 8, a number of slits 82s are formed in the bottom of the Faraday shielding plate 82. Each slit 82s extends approximately perpendicular to the corresponding side of the antenna 85, which has a roughly octagonal planar shape.

[0048] As shown in Figures 7 and 8, the Faraday shielding plate 82 has support portions 82a that bend outward at two locations on its upper end. The support portions 82a are supported on the upper surface of the frame member 81, thereby supporting the Faraday shielding plate 82 in a predetermined position within the frame member 81.

[0049] The insulating plate 83 is made of, for example, quartz glass and is slightly smaller than the bottom surface of the Faraday shielding plate 82. The insulating plate 83 is placed on the bottom surface of the Faraday shielding plate 82. The insulating plate 83 insulates the Faraday shielding plate 82 from the antenna 85, while allowing high-frequency radio waves radiated from the antenna 85 to pass downwards.

[0050] Antenna 85 is formed by winding a hollow copper tube (pipe) in, for example, three times so that its planar shape is approximately octagonal. Cooling water can be circulated within the pipe, thereby preventing the antenna 85 from being heated to a high temperature by the high-frequency waves supplied to it. An upright portion 85a is provided on the antenna 85. A support portion 85b is attached to the upright portion 85a. The support portion 85b maintains the antenna 85 in a predetermined position within the Faraday shielding plate 82. A high-frequency power supply 87 is connected to the support portion 85b via a matching box 86. The high-frequency power supply 87 generates a high frequency having, for example, a frequency of 13.56 MHz.

[0051] According to the plasma generator 80, when high-frequency power is supplied from the high-frequency power supply 87 to the antenna 85 via the matching box 86, an electromagnetic field is generated by the antenna 85. The electric field component of this electromagnetic field is shielded by the Faraday shielding plate 82 and therefore cannot propagate downward. On the other hand, the magnetic field component propagates into the reforming region P3 through the multiple slits 82s of the Faraday shielding plate 82. The magnetic field component activates the mixed gas of the rare gas and additive gas supplied from the reforming gas nozzle 33 to the reforming region P3 at a predetermined flow rate ratio.

[0052] As shown in Figure 1, the film deposition apparatus according to this embodiment is equipped with a control unit 100, which is a computer for controlling the operation of the entire apparatus. The memory of the control unit 100 stores a program that causes the film deposition apparatus to perform the film deposition method described later under the control of the control unit 100. The program is structured into a group of steps to execute the film deposition method described later. The program is stored on a medium 102 such as a hard disk, compact disk, magneto-optical disk, memory card, or flexible disk, and is read into a storage unit 101 by a predetermined reading device and installed in the control unit 100.

[0053] [Film forming method] The film deposition method according to the embodiment will be described with reference to Figures 10 to 15. In the following description, the case in which a titanium oxide film is formed on the surface of a substrate W using the aforementioned film deposition apparatus will be used as an example. Figures 10 to 15 are cross-sectional views showing the film deposition method according to the embodiment.

[0054] Figure 10 shows an example of a surface pattern of a substrate W used in the film deposition method according to the embodiment. As shown in Figure 10, a substrate W having a plurality of trenches T on its surface is prepared. The substrate W is, for example, a silicon wafer.

[0055] Next, a gate valve (not shown) is opened, and the substrate W is transferred from the outside via the transfer opening 15 (Figures 2 and 3) to the recess 24 of the rotary table 2 by the transfer arm 10 (Figure 3). The transfer of the substrate W is performed by raising and lowering a lifting pin (not shown) from the bottom side of the vacuum container 1 through a through hole in the bottom surface of the recess 24 when the recess 24 stops in a position facing the transfer opening 15. The transfer of the substrate W is performed by intermittently rotating the rotary table 2, and the substrate W is placed in each of the five recesses 24 of the rotary table 2.

[0056] Next, the gate valve is closed and the vacuum chamber 1 is evacuated by the vacuum pump 640 to the achievable vacuum level. Then, nitrogen gas, which is the separation gas, is discharged at a predetermined flow rate from the separation gas nozzles 41 and 42, and nitrogen gas is also discharged at a predetermined flow rate from the separation gas supply pipe 51 and the purge gas supply pipes 72 and 73. Accordingly, the pressure controller 650 (Figure 1) controls the pressure inside the vacuum chamber 1 to a preset processing pressure. Next, the rotary table 2 is rotated clockwise at a high rotational speed, for example, 120 rpm, while the heater unit 7 heats the substrate W to, for example, 200°C.

[0057] Next, organic aminotitanium gas is supplied from the raw material gas nozzle 31 (Figures 2 and 3), and hydrogen peroxide gas is supplied from the reaction gas nozzle 32. At this time, the raw material gas nozzle 31 supplies organic aminotitanium gas from each discharge hole 31h at a first angle θ1 with respect to the vertically downward direction. The reaction gas nozzle 32 supplies hydrogen peroxide gas from each discharge hole 32h at a second angle θ2 with respect to the vertically downward direction.

[0058] Next, as the rotary table 2 rotates, the substrate W repeatedly passes through the adsorption region P1, the separation region D, the oxidation region P2, and the separation region D in that order (see Figure 3).

[0059] Figure 11 shows an example of the adsorption process. In the adsorption region P1, as shown in Figure 11, organic aminotitanium gas molecules Mt are adsorbed onto the surface U of the substrate W, forming an organic aminotitanium molecular layer 61. Here, the organic aminotitanium gas is supplied at a first angle θ1 with respect to the depth direction of the trench T. In this case, the organic aminotitanium molecules Mt have difficulty reaching the depths of the trench T and are therefore more likely to be adsorbed onto the surface U of the substrate W. The organic aminotitanium gas molecules Mt are organometallic gases, with organic groups attached around the titanium, which is a metal, and the diameter of the molecules Mt is large. Furthermore, the rotary table 2 rotates at high speed. For this reason, the organic aminotitanium molecules Mt do not reach the depths of the trench T and are adsorbed onto the surface U of the substrate.

[0060] Figures 12 and 13 show an example of the oxidation process. As shown in Figure 12, after passing through the separation region D, the organic aminotitanium gas adsorbed on the surface U of the substrate W is oxidized by hydrogen peroxide gas molecules Mo in the oxidation region P2. As a result, as shown in Figure 13, a titanium oxide film 62 is formed on the surface U of the substrate W at the upper end of the trench T. Here, the hydrogen peroxide gas is supplied at a second angle θ2 with respect to the depth direction of the trench T. In this case, the hydrogen peroxide gas molecules Mo have difficulty reaching the back of the trench T, so the titanium oxide film 62 is easily formed on the surface U of the substrate W. Furthermore, because the rotary table 2 is rotating at high speed, the hydrogen peroxide gas molecules Mo do not reach the back of the trench T, and the titanium oxide film 62 is formed on the surface U of the substrate.

[0061] Figure 14 shows an example of a repeated adsorption process. As shown in Figure 14, when the substrate W reaches the adsorption region P1 again due to the rotation of the rotary table 2, molecules Mt of organic aminotitanium gas supplied from the raw material gas nozzle 31 are adsorbed onto the surface U of the substrate W. Here, as in the adsorption process described above, the organic aminotitanium molecules Mt do not reach the depths of the trench T, but are adsorbed on the surface U of the substrate W.

[0062] Subsequently, while the rotary table 2 continues to rotate at high speed, the adsorption process and the oxidation process are repeated, resulting in the formation of a helmet-shaped titanium oxide film 62 on the surface (on the protrusions) of the substrate W between the trenches T, as shown in Figure 15, covering the upper surface and upper side of the protrusions.

[0063] As described above, according to the film formation method of the embodiment, organic aminotitanium gas and hydrogen peroxide gas are supplied at an angle to the depth direction of the trench T. As a result, the thickness of the titanium oxide film 62 formed above the protrusions becomes thicker than that formed below the protrusions. In addition, the thickness of the titanium oxide film 62 formed on the upper surface of the protrusions tends to be thicker than that of the titanium oxide film 62 formed on the side surfaces of the protrusions. As a result, a film having a helmet shape with suppressed overhang (low overhang rate) can be formed.

[0064] Furthermore, according to the film deposition method of this embodiment, an organometallic gas with a large molecular diameter is supplied as a raw material gas from the raw material gas nozzle 31, and the rotary table 2 is rotated at high speed. As a result, film deposition does not proceed within the trench T, and film deposition is selectively performed only in the region between the trenches T, thereby forming a localized titanium oxide film 62. In the above embodiment, the case in which organic aminotitanium gas is used as the raw material gas was described, but since organometallic gases generally have a large molecular diameter, it is also possible to carry out the film deposition method of this embodiment using other types of organometallic gases. Moreover, not only organometallic gases but also organometallic gases such as organosilane gas have a large molecular diameter, and the film deposition method of this embodiment can also be carried out using them.

[0065] The film deposition method according to the above embodiment describes a case where both the raw material gas and the oxidizing gas are supplied at an angle to the vertically downward direction, but is not limited to this. For example, the raw material gas may be supplied vertically downward, and the oxidizing gas may be supplied at an angle to the vertically downward direction. For example, the raw material gas may be supplied at an angle to the vertically downward direction, and the oxidizing gas may be supplied vertically downward. In this way, it is sufficient to supply at least one of the raw material gas and the oxidizing gas at an angle to the vertically downward direction.

[0066] The film formation method according to the above embodiment describes the case of forming a titanium oxide film, but is not limited to this. For example, when forming a titanium nitride film, the type of gas supplied from the reaction gas nozzle 32 can be changed from hydrogen peroxide gas to a nitriding gas such as ammonia gas.

[0067] [Examples] In this embodiment, a substrate having multiple protrusions on its surface was prepared, the prepared substrate was placed in the vacuum chamber 1 of the aforementioned film deposition apparatus, and a titanium oxide film was formed on the surface of the substrate under the conditions A1 and A2 shown below.

[0068] (Condition A1) Under condition A1, the adsorption and oxidation processes described above were carried out sequentially in the order described above, with the first angle θ1 set to 70° and the second angle θ2 set to 90°, to form a titanium oxide film. Specifically, under condition A1, the raw material gas was supplied at an angle of 70° to the vertically downward direction during the adsorption process, and the oxidizing gas was supplied parallel to the surface of the substrate during the oxidation process. TDMAT gas was supplied as the raw material gas during the adsorption process. Hydrogen peroxide gas was supplied as the oxidizing gas during the oxidation process.

[0069] (Condition A2) Under condition A2, the second angle θ2 was set to 0°. All other conditions were the same as in condition A1. Specifically, under condition A2, the raw material gas was supplied at an angle of 70° to the vertically downward direction during the adsorption process, and the oxidizing gas was supplied perpendicular to the surface of the substrate during the oxidation process.

[0070] Next, the thickness T1 (Figure 9) of the titanium oxide film formed on the substrate surface was measured on the bottom surface of the trench, the thickness T2 (Figure 9) in the region between adjacent trenches, and the thickness T3 on the upper side surface of the trench. The overhang ratio was also calculated from thicknesses T2 and T3.

[0071] In the titanium oxide film formed on the substrate surface under condition A1, the thickness T1 was 4.4 nm, the thickness T2 was 11.8 nm, and the thickness T3 was 7.7 nm. The overhang ratio was 65%.

[0072] In the titanium oxide film formed on the substrate surface under condition A2, the thickness T1 was 5.5 nm, the thickness T2 was 12.1 nm, and the thickness T3 was 8.7 nm. The overhang ratio was 72%.

[0073] The results above demonstrate that supplying the oxidizing gas parallel to the substrate surface during the oxidation process suppresses the overhang of the titanium oxide film formed on the convex portions more effectively than supplying the oxidizing gas perpendicular to the substrate surface during the oxidation process.

[0074] Next, the cycle rate, in-plane uniformity of film thickness, refractive index, and wet etching rate (WER) were measured for the titanium oxide film formed on the substrate surface. The cycle rate was calculated by measuring the film thickness of the titanium oxide film and dividing the measured film thickness by the number of repetitions of the adsorption and oxidation processes. The WER is the etching rate when the titanium oxide film is etched with dilute hydrofluoric acid (DHF).

[0075] The cycle rate of the titanium oxide film formed on the substrate surface under condition A1 was 0.198 Å / cycle. The cycle rate of the titanium oxide film formed on the substrate surface under condition A2 was 0.197 Å / cycle. These results indicate that the cycle rates of the titanium oxide film formed on the substrate surface under condition A1 and the titanium oxide film formed under condition A2 are equivalent. Furthermore, it was shown that a titanium oxide film with a helmet shape and suppressed overhang (low overhang rate) can be formed at a relatively high cycle rate of approximately 0.2 Å / cycle.

[0076] Furthermore, the in-plane uniformity of the film thickness was equivalent between the titanium oxide film formed on the substrate surface under condition A1 and the titanium oxide film formed on the substrate surface under condition A2.

[0077] Figure 16 shows the WER and refractive index of a titanium oxide film formed on the surface of a substrate. In Figure 16, the left vertical axis represents WER [nm / min], and the right vertical axis represents the refractive index. In Figure 16, the bar graph shows the WER measurement results, and the circles show the refractive index measurement results.

[0078] As shown in Figure 16, it can be seen that the WER and refractive index are equivalent between the titanium oxide film formed on the substrate surface under condition A1 and the titanium oxide film formed on the substrate surface under condition A2.

[0079] These results demonstrate that changing the direction in which the oxidizing gas is supplied during the oxidation process has almost no effect on the film properties of the titanium oxide film.

[0080] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The above embodiments may be omitted, replaced, or modified in various ways without departing from the scope and spirit of the appended claims. [Explanation of symbols]

[0081] 1 Vacuum container 2 Rotating Tables 31. Raw material gas nozzle 32 Reaction gas nozzle P1 Adsorption area P2 oxidation region W board

Claims

1. A method for forming a film on the surface of a substrate having a protrusion on its surface, (a) A step of supplying a raw material gas onto the surface of the substrate and adsorbing the raw material gas onto the surface of the substrate, (b) A step of supplying a reaction gas onto the surface of the substrate and forming a film on the surface of the substrate by a thermal reaction between the raw material gas adsorbed on the surface of the substrate and the reaction gas, It has, The substrate is arranged circumferentially on the surface of a rotating table provided inside a vacuum chamber. Within the vacuum vessel, above the rotating table and along the circumferential direction of the rotating table, are provided an adsorption region for carrying out step (a) and a reaction region for carrying out step (b). With the raw material gas supplied to the adsorption region from the raw material gas supply unit and the reaction gas supplied to the reaction region from the reaction gas supply unit, the rotary table is rotated, thereby repeatedly performing steps (a) and (b) on the substrate. The raw material gas supply unit supplies gas at a first angle downstream of the rotation direction of the rotary table relative to the vertically downward direction. Film formation method.

2. The first angle is between 60° and 80°. The method for forming a film according to claim 1.

3. The reaction gas supply unit supplies the reaction gas at a second angle with respect to the vertically downward direction. The method for forming a film according to claim 1 or 2.

4. The aforementioned second angle is between 80° and 100°. The method for forming a film according to claim 3.

5. The aforementioned raw material gas is an organometallic gas or an organometallic gas. The reaction gas is an oxidizing gas. The method for forming a film according to claim 1.

6. The aforementioned raw material gas is an organometallic gas or an organometallic gas. The reaction gas is a nitride gas. The method for forming a film according to claim 1.

7. A film-forming apparatus for forming a film on the surface of a substrate having a protrusion on its surface, A rotating table provided inside a vacuum container, on which the substrate is positioned circumferentially on its surface, An adsorption region and a reaction region are provided above the rotating table in the vacuum container, along the circumferential direction of the rotating table, A raw material gas supply unit that supplies raw material gas to the adsorption region, A reaction gas supply unit that supplies reaction gas to the reaction region, Control unit and Equipped with, The raw material gas supply unit is configured to supply gas at a first angle downstream of the rotation direction of the rotary table with respect to the vertically downward direction. The control unit, By supplying the raw material gas from the raw material gas supply unit to the adsorption region and supplying the reaction gas from the reaction gas supply unit to the reaction region, and then rotating the rotary table, A step of supplying the raw material gas onto the surface of the substrate placed on the surface of the rotating table, and adsorbing the raw material gas onto the surface of the substrate, A step of supplying the reaction gas onto the surface of the substrate placed on the surface of the rotating table, and forming a film on the surface of the substrate by a thermal reaction between the raw material gas adsorbed on the surface of the substrate and the reaction gas, The film deposition apparatus is configured to be controlled to perform the process repeatedly. Film deposition equipment.

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