Film forming method and film-forming apparatus

Abstract

To provide a technique that enables a titanium oxynitride film to be easily formed into a target shape.SOLUTION: A film forming method forms a titanium oxynitride film on a substrate. The film forming method includes the steps of: (a) supplying a titanium-containing gas to the substrate; and (b) supplying an oxidizing gas to the substrate to which the titanium-containing gas has been supplied, and supplying a shape control gas to an area same as that to which the oxidizing gas is supplied, thereby, adjusting a shape of the titanium oxynitride film. This enables the film forming method to easily form the titanium oxynitride film into a target shape.SELECTED DRAWING: Figure 6

Description

[Technical field]

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

[0002] Patent Document 1 discloses a method for forming a protective film on flat regions (protrusions) between multiple recesses formed on the surface of a substrate. This method forms an organic metal or organic metalloid oxide film on the flat regions, and then etches the side surfaces of the oxide film.

[0003] However, it is known that titanium oxide (TiO) films, which are oxide films formed on substrates, are difficult to remove by peeling, etc. Therefore, when removing them by peeling, etc., it is considered to form a titanium oxynitride (TiON) film, which is easier to remove, on the surface of the substrate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-102807 A Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure provides a technique that can easily form a titanium oxynitride film in a target shape. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, there is provided a method for forming a titanium oxynitride film on a substrate, the method comprising the steps of: (a) supplying a titanium-containing gas to the substrate; and (b) supplying an oxidizing gas to the substrate to which the titanium-containing gas has been supplied, and supplying a shape-controlling gas to the same area as the oxidizing gas, to adjust a shape of the titanium oxynitride film. Effect of the Invention

[0007] According to one embodiment, the titanium oxynitride film can be easily formed into a target shape. [Brief description of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view illustrating a film forming apparatus according to an embodiment of the present invention. [Diagram 2] 2 is a plan view illustrating the inside of a processing chamber of a film forming apparatus. FIG. [Diagram 3] 1 is a partial cross-sectional view of a processing vessel along the concentric circles of a rotary table from a source gas nozzle, a separation gas nozzle, and a reaction gas nozzle. [Figure 4] 4 is a flowchart showing a film forming method of the film forming apparatus. [Diagram 5] 1 is a graph showing the component ratio of a titanium oxynitride film formed by a film forming method. [Figure 6] Fig. 6(A) is an enlarged cross-sectional view of a protruding portion of a substrate W on which a film has been formed, and Fig. 6(B) is a graph showing an analysis of the state of a film formed on the protruding portion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and duplicated descriptions may be omitted.

[0010] Fig. 1 is a cross-sectional view that illustrates a film formation apparatus 100 according to an embodiment. Fig. 2 is a plan view that illustrates an interior of a processing vessel 1 of the film formation apparatus 100. As illustrated in Figs. 1 and 2, the film formation apparatus 100 according to the embodiment is a substrate processing apparatus that forms a film on a surface of a substrate W by atomic layer deposition (ALD) or molecular layer deposition (MLD). The film formation apparatus 100 includes a processing vessel 1 that accommodates the substrate W therein and performs a film formation process, and a turntable 2 that is rotatably provided within the processing vessel 1.

[0011] The processing vessel 1 is formed in a flat cylindrical shape and has a processing chamber therein for accommodating a substrate W. For example, the processing vessel 1 is configured by assembling a vessel body 12 having an open top and a top plate 11 disposed on the upper part of the vessel body 12. For convenience of explanation, the top plate 11 is not shown in FIG. 2. The vessel body 12 has a disk-shaped bottom 14 and a side portion 13 protruding vertically upward from the outer edge of the bottom portion 14. The side portion 13 of the vessel body 12 and the top plate 11 are fixed airtight via a seal member 15 such as an O-ring.

[0012] The turntable 2 is formed in an annular shape, and its inner periphery is fixed to a cylindrical core part 21. The core part 21 is fixed to the upper end of a rotation shaft 22 extending in the vertical direction. The rotation shaft 22 penetrates the bottom part 14 of the processing vessel 1, and its lower end is held by a driving part 23. The driving part 23 rotates the rotation shaft 22 about its axis. As a result, the turntable 2 rotates via the rotation shaft 22 and the core part 21, with the center of the processing vessel 1 as the center of rotation.

[0013] The rotating shaft 22 and the driving unit 23 are housed in a cylindrical case body 20 that is open at the top. The case body 20 has a flange portion at the upper end, and is airtightly fixed to the bottom portion 14 of the processing vessel 1. Therefore, the internal space of the case body 20 is isolated from the outside of the case body 20 and is in communication with the processing chamber of the processing vessel 1.

[0014] As shown in Fig. 2, a plurality of (five in Fig. 2) circular mounting recesses 24 (mounting portions) on which a substrate W can be mounted are provided on the upper surface of the turntable 2 along the direction of rotation of the turntable 2. Examples of the substrate W to be subjected to the film formation process include semiconductor wafers such as silicon semiconductors, compound semiconductors, and oxide semiconductors. The substrate W may have recesses Wc and protrusions Ws (see Fig. 6) such as trenches and vias on its surface.

[0015] The mounting recess 24 has an inner diameter slightly larger than the diameter of the substrate W (e.g., 300 mm), and a depth approximately equal to the thickness of the substrate W. As a result, when the substrate W is placed in the mounting recess 24, the upper surface of the substrate W and the upper surface of the turntable 2 (the area on which the substrate W is not placed) are at approximately the same height.

[0016] The film forming apparatus 100 includes a gas supply unit 30 for supplying gas into the inside of the processing vessel 1. The gas supply unit 30 includes a plurality of gas nozzles 30N formed of, for example, quartz and extending linearly. Each gas nozzle 30N has an inlet port 30a, which is a base end, fixed to a side portion 13 of the processing vessel 1, and extends radially inside the processing vessel 1 to near the central region. Each gas nozzle 30N extends parallel to the upper surface of the turntable 2 in the processing vessel 1. Each gas nozzle 30N has a plurality of gas discharge holes 30h that open vertically downward toward the turntable 2 (see also FIG. 3). Each gas discharge hole 30h is arranged at equal intervals along the axial direction (the radial direction of the processing vessel 1).

[0017] The gas supply unit 30 includes a raw material gas supply unit 31 that supplies a raw material gas, a reactive gas supply unit 32 that supplies a reactive gas, a shape-controlling gas supply unit 33 that supplies a shape-controlling gas, and a first separation gas supply unit 34 and a second separation gas supply unit 35 that supply a separation gas. The raw material gas supply unit 31 has three raw material gas nozzles 31N as the gas nozzle 30N. The reactive gas supply unit 32 has one reactive gas nozzle 32N as the gas nozzle 30N. The shape-controlling gas supply unit 33 ejects the shape-controlling gas using the reactive gas nozzle 32N. The first separation gas supply unit 34 has one first separation gas nozzle 34N as the gas nozzle 30N. The second separation gas supply unit 35 has one second separation gas nozzle 35N as the gas nozzle 30N. The processing vessel 1 in the illustrated example has one second separation gas nozzle 35N, three raw material gas nozzles 31N, one first separation gas nozzle 34N, and one reaction gas nozzle 32N arranged in that order clockwise from the transfer port 16 provided on the side 13.

[0018] The raw material gas supply unit 31 connects a raw material gas supply path 41 to the inlet port 30a of each raw material gas nozzle 31N protruding to the outside of the processing vessel 1. The raw material gas supply unit 31 includes a raw material gas supply source 411, an opening / closing valve 412, a flow rate regulator 413, and the like on the raw material gas supply path 41.

[0019] The film forming apparatus 100 according to the embodiment forms a titanium oxynitride (TiON) film on the surface of the substrate W. When forming a titanium oxynitride film, the raw material gas supplied by the raw material gas supply unit 31 is a titanium-containing gas containing titanium (Ti), which is a metal element. Examples of the titanium-containing gas include tetrakis(dimethylamino)titanium (Ti[N(CH3)2]4), titanium tetrachloride (TiCl4), TiCp(NMe2)3, TiMe5Cp(NMe2)3, and tetraisopropyl titanate (Ti(OCH(CH3)2)4). In the embodiment, tetrakis(dimethylamino)titanium is used as the titanium-containing gas (abbreviated as TDMAT, and hereinafter also referred to as TDMAT).

[0020] The three source gas nozzles 31N include a nozzle for supplying the TDMAT gas toward the center of the turntable 2, a nozzle for supplying the TDMAT gas over substantially the entire radial direction of the turntable 2, and a nozzle for supplying the TDMAT gas toward the outer periphery of the turntable 2. This allows the TDMAT gas to be evenly adsorbed onto the surface of the substrate W while the substrate W is moving in the circumferential direction of the turntable 2.

[0021] The reactive gas supply unit 32 connects a reactive gas supply path 42 to the inlet port 30a of each reactive gas nozzle 32N protruding to the outside of the processing chamber 1. The reactive gas supply unit 32 includes a reactive gas supply source 421, an opening / closing valve 422, a flow rate regulator 423, and the like on the reactive gas supply path 42.

[0022] The reactive gas supplied by the reactive gas supply unit 32 is selected as an oxidizing gas that reacts with and oxidizes TDMAT (titanium-containing precursor) adsorbed on the surface of the substrate W. In this embodiment, the reactive gas is oxygen (O2) gas.

[0023] The shape-controlling gas supply unit 33 has a shape-controlling gas supply path 43 connected to a midpoint of the reactive gas supply path 42, and mixes the shape-controlling gas and oxygen gas from the reactive gas supply path 42 and distributes the resulting mixture to the inlet port 30a of the reactive gas nozzle 32N. The shape-controlling gas supply unit 33 includes a shape-controlling gas supply source 431, an opening / closing valve 432, a flow rate regulator 433, and the like on the shape-controlling gas supply path 43.

[0024] The shape control gas is selected from gases that react with oxygen and titanium on the surface of the substrate W. In this embodiment, the shape control gas is ammonia (NH3) gas. Shape control of the titanium oxynitride film by supplying the shape control gas will be described in detail later. The shape control gas supply unit 33 may be configured to include a shape control gas nozzle in the processing vessel 1 in addition to the reaction gas nozzle 32N, and to eject the shape control gas from this shape control gas nozzle.

[0025] The first separation gas supply unit 34 connects a separation gas supply path (not shown) to the inlet port 30a of the first separation gas nozzle 34N protruding to the outside of the processing vessel 1. The first separation gas supply unit 34 is equipped with a separation gas supply source, an on-off valve, a flow rate regulator, etc. (all not shown) on the separation gas supply path. The second separation gas supply unit 35 connects a separation gas supply path (not shown) to the inlet port 30a of the second separation gas nozzle 35N protruding to the outside of the processing vessel 1. The second separation gas supply unit 35 is equipped with a separation gas supply source, an on-off valve, a flow rate regulator, etc. (all not shown) on the separation gas supply path.

[0026] The separation gas supplied by the first separation gas supply unit 34 and the second separation gas supply unit 35 is appropriately selected from rare gases such as argon (Ar) and helium (He), and inert gases such as nitrogen (N2) gas, etc. In the embodiment, nitrogen gas is used as the separation gas.

[0027] The processing vessel 1 also includes two internal convex portions 4 arranged along the circumferential direction. The convex portions 4 have a generally sector-shaped planar shape cut into an arc. In the embodiment, the inner arc is connected to a protruding portion 5 described below, and the outer arc is disposed along the inner circumferential surface of a side portion 13 of the processing vessel 1.

[0028] 3 is a partial cross-sectional view of the processing vessel 1 along the concentric circle of the turntable 2 from the source gas nozzle 31N, the first separation gas nozzle 34N, and the reaction gas nozzle 32N. As shown in FIG. 3, the convex portion 4 is attached to the lower surface of the top plate 11. Therefore, inside the processing vessel 1, there are a flat low ceiling surface 46 which is the lower surface of the convex portion 4, and ceiling surfaces 47 which are located on both sides of the ceiling surface 46 in the circumferential direction and are higher than the ceiling surface 46.

[0029] A groove 4a is formed in the convex portion 4, extending along the radial direction of the turntable 2. A first separation gas nozzle 34N is housed in this groove 4a. A similar groove 4a is formed in the other convex portion 4, and a second separation gas nozzle 35N is housed in this groove 4a (see FIG. 2).

[0030] 3, a source gas nozzle 31N is provided in a space 481 (the space vertically below the high ceiling surface 47) on the right side of the convex portion 4. A reactive gas nozzle 32N is provided in a space 482 (the space vertically below the high ceiling surface 47) on the left side of the convex portion 4. These gas nozzles 30N are provided in the vicinity of the substrate W, spaced apart from the ceiling surface 47.

[0031] On the other hand, the low ceiling surface 46 forms a narrow space, separation space H, relative to the turntable 2. Since the volume of the separation space H is smaller than the volumes of the spaces 481 and 482, when nitrogen gas (separation gas) is supplied from the first separation gas nozzle 34N, the pressure in the separation space H can be made higher than the pressures in the spaces 481 and 482 by the nitrogen gas. As a result, the separation space H forms a pressure barrier between the spaces 481 and 482. Moreover, the nitrogen gas flowing out from the separation space H to the spaces 481 and 482 acts as a counterflow between the source gas and the reaction gas. Therefore, the source gas and the reaction gas are separated by the separation space H, and are prevented from mixing with each other and reacting with each other.

[0032] 1 and 2, the protrusion 5 provided on the underside of the top plate 11 surrounds the outer periphery of the core portion 21 that fixes the rotary table 2. This protrusion 5 is continuous with the part of the convex portion 4 on the rotation center side, and its underside is formed at the same height as the ceiling surface 46.

[0033] Further, exhaust ports 61 are formed between the turntable 2 and the side portion 13 of the container body 12. An exhaust pipe 630 is connected to the exhaust port 61, and this exhaust pipe 630 is connected via a pressure regulator 650 to a vacuum pump 640 which is a vacuum exhaust means.

[0034] A heater unit 7, which is a heating means, is provided in the space between the bottom 14 of the processing vessel 1 and the turntable 2. The heater unit 7 heats the substrate W on the turntable 2 to a target temperature (e.g., 225° C.) determined by a recipe. A ring-shaped cover member 71 is provided below the periphery of the turntable 2 to prevent gas from entering the space below the turntable 2.

[0035] The bottom 14 at a portion closer to the center of rotation than the space in which the heater unit 7 is disposed is a protruding portion 12a that protrudes upward so as to approach the core portion 21 at the center of the lower surface of the turntable 2. A narrow space is formed between the protruding portion 12a and the core portion 21. In addition, the gap between the inner peripheral surface of the through hole of the rotating shaft 22 penetrating the bottom 14 and the rotating shaft 22 is narrow, and this narrow space is connected to the case body 20. A lid member 7a is provided between the heater unit 7 and the turntable 2, covering the area between the cover member 71 and the upper end of the protruding portion 12a in the circumferential direction. The lid member 7a is made of, for example, quartz, and suppresses the intrusion of gas into the heater unit 7.

[0036] A purge gas supply pipe 72 that supplies nitrogen gas, which is a purge gas (the same gas as the separation gas supplied by the first separation gas nozzle 34N), into the narrow space is provided in the case body 20. Furthermore, a plurality of purge gas supply pipes 73 for purging the arrangement space of the heater unit 7 are provided at appropriate intervals along the circumferential direction in the bottom 14 below the heater unit 7.

[0037] When purge gas is supplied from the purge gas supply pipe 72, the purge gas flows through a gap between the inner circumferential surface of the through hole of the rotating shaft 22 and the rotating shaft 22, and a gap between the protruding portion 12a and the core portion 21, into the space between the turntable 2 and the lid member 7a, and is exhausted from the multiple exhaust ports 61. When purge gas is supplied from the purge gas supply pipe 73, the purge gas flows out from the space in which the heater unit 7 is accommodated through a gap (not shown) between the lid member 7a and the cover member 71, and is exhausted from the multiple exhaust ports 61. Due to these flows of purge gas, it is possible to prevent the source gas and the reaction gas from mixing through the space below the center of the processing vessel 1 and the space below the turntable 2.

[0038] In addition, a separation gas supply pipe 51 is connected to the center of the top plate 11 of the processing vessel 1. The separation gas supply pipe 51 supplies nitrogen gas (the same gas as the separation gas supplied by the first separation gas nozzle 34N) to the space between the top plate 11 and the core portion 21. The nitrogen gas supplied to this space flows along the surface of the turntable 2 through the narrow space between the protrusion 5 and the turntable 2. The space between the protrusion 5 and the turntable 2 is maintained at a pressure higher than that of the nitrogen gas. Therefore, the raw material gas and the reaction gas are prevented from mixing through the central region C.

[0039] 2, a transfer port 16 is formed in the side wall of the processing vessel 1, through which the substrate W is transferred between an external transfer arm 80 and the turntable 2. This transfer port 16 is opened and closed by a gate valve (not shown). A mounting recess 24, which is a substrate mounting area in the turntable 2, receives and transfers the substrate W between the mount recess 24 and the transfer arm 80 at a position facing the transfer port 16. For this reason, the film forming apparatus 100 is provided with lift pins and a lift mechanism (neither of which is shown) that penetrate the mounting recess 24 and lift the substrate W from the backside, at a position adjacent to the transfer port 16 on the lower side of the turntable 2.

[0040] The film forming apparatus 100 also includes a control unit 90 that controls the operation of the entire apparatus. The control unit 90 is a computer having a processor, memory, an input / output interface, and a communication interface (not shown). The processor is a combination of one or more of a central processing unit (CPU), a graphics processing unit (GPU), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a circuit made of a plurality of discrete semiconductors, and executes a program stored in the memory. The memory includes a main storage device made of a semiconductor memory or the like, and an auxiliary storage device made of a disk, a semiconductor memory (flash memory), or the like.

[0041] The above-described film forming apparatus 100 supplies TDMAT gas, oxygen gas, ammonia gas, and nitrogen gas to the processing chamber of the processing vessel 1 under the control of the controller 90. In a plan view, the processing vessel 1 can separate a source gas processing space P1 to which the TDMAT gas is supplied and a reactive gas processing space P2 to which oxygen gas and ammonia gas are supplied by supplying nitrogen gas to the separation space H. In particular, the film forming apparatus 100 supplies oxygen gas and ammonia gas to the reactive gas processing space P2 (the same area) to adjust the shape of the titanium oxynitride film to be formed by these gases.

[0042] The film formation apparatus 100 according to the embodiment is basically configured as described above, and its operation (film formation method) will be described below with reference to Fig. 4. Fig. 4 is a flowchart showing the film formation method of the film formation apparatus 100. The film formation apparatus 100 performs steps S101 to S106 shown in Fig. 4 under the control of the control unit 90.

[0043] Specifically, the control unit 90 first opens the gate valve, and causes the transfer arm 80 to load the substrate W through the transfer port 16 (FIG. 2) and place it in the mounting recess 24 of the turntable 2 (step S101). At this time, the control unit 90 intermittently rotates the turntable 2 to sequentially place the substrates W in each mounting recess 24. After each substrate W is loaded, the control unit 90 closes the gate valve to hermetically seal the processing vessel 1.

[0044] After sealing the processing vessel 1, the control unit 90 performs preparations for the film formation process. The control unit 90 discharges nitrogen gas from the first separation gas nozzle 34N and the second separation gas nozzle 35N, and evacuates the gas using the vacuum pump 640 and the pressure regulator 650, thereby adjusting the entire processing chamber of the processing vessel 1 to a target pressure (step S102). At this time, the control unit 90 may also discharge nitrogen gas from the separation gas supply pipe 51 and the purge gas supply pipes 72 and 73.

[0045] Furthermore, as a preparation for the film formation process, the control unit 90 heats the substrate W to a target temperature by the heater unit 7 and rotates the turntable 2 clockwise at a target rotation speed (step S103). During the film formation process, the film formation apparatus 100 maintains the target pressure, temperature, and rotation speed set in steps S102 and S103. Note that the target pressure, temperature, and rotation speed may be changed depending on the contents (recipe) of the film formation process.

[0046] After the advance preparation is completed, the control unit 90 supplies the TDMAT gas, nitrogen gas, oxygen gas, and ammonia gas from the gas supply unit 30 to the processing chamber 1 to perform a film forming process on each substrate W rotated by the turntable 2 (step S104). The TDMAT gas, oxygen gas, and ammonia gas are separated in the separation spaces H (first separation space H1, second separation space H2) of the two convex parts 4 supplying the nitrogen gas, and are prevented from being mixed with each other in the processing chamber 1.

[0047] The above step S104 includes a process (process (A)) of supplying TDMAT gas to the raw material gas processing space P1 by the raw material gas supply unit 31. When the substrate W passes through the raw material gas processing space P1 by the rotation of the turntable 2, the TDMAT gas (titanium-containing precursor) supplied from the raw material gas nozzle 31N is adsorbed onto the surface of the substrate W.

[0048] When the substrate W on the turntable 2 passes through the first separation space H1 after the source gas processing space P1, nitrogen gas is supplied from the first separation gas nozzle 34N. This removes the TDMAT gas floating around the substrate W. The nitrogen gas also increases the pressure in the first separation space H1 and flows into the source gas processing space P1 and the reactive gas processing space P2 around the convex portion 4, separating these spaces.

[0049] Furthermore, the above step S104 includes a process (process (B)) of supplying oxygen gas to the reactive gas processing space P2 by the reactive gas supply unit 32 and supplying ammonia gas to the reactive gas processing space P2 by the shape control gas supply unit 33. That is, the substrate W on the turntable 2 moves to the reactive gas processing space P2 after the first separation space H1, and mixed oxygen gas and ammonia gas are supplied from each reactive gas nozzle 32N. For example, the gas supply unit 30 supplies oxygen gas at a supply rate of 6000 sccm to the reactive gas processing space P2. Also, for example, the gas supply unit 30 supplies ammonia gas at a supply rate of 1000 sccm to the reactive gas processing space P2. As a result, the reactive gas processing space P2 is in a state where a large amount of oxygen gas and ammonia gas are mixed.

[0050] As a result, in the reactive gas processing space P2, a reaction occurs between the titanium precursor, oxygen, and ammonia on the surface of the substrate W. The ammonia is decomposed into nitrogen atoms and hydrogen atoms and reacts with titanium, and the oxygen is also decomposed into oxygen atoms and reacts with titanium. Thus, a titanium oxynitride film is formed on the surface of the substrate W.

[0051] In particular, by supplying oxygen gas and ammonia gas to the same reactive gas processing space P2, it is possible to suppress the excessive generation of titanium oxide due to the reaction between titanium and oxygen. The ammonia gas changes the shape of the film on the recesses Wc and protrusions Ws of the substrate W according to the amount of ammonia gas supplied (see also FIG. 6). The action of this ammonia gas will be described later.

[0052] When the substrate W on the turntable 2 passes through the second separation space H2 after the reactive gas processing space P2, nitrogen gas is supplied from the second separation gas nozzle 35N. This removes oxygen gas, ammonia gas, and reaction by-products remaining on the surface of the substrate W. The nitrogen gas also flows into the source gas processing space P1 and the reactive gas processing space P2 around the convex portion 4 while increasing the pressure in the second separation space H2, separating these spaces. After passing through the second separation space H2, the substrate on the turntable 2 returns to the source gas processing space P1 again.

[0053] In step S104, the control unit 90 determines whether or not to continue the film formation process. If the film formation process is to be continued (step S105: YES), the process returns to step S102, and the same process flow is repeated. As a result, a titanium oxynitride film is gradually deposited on the surface of the substrate W. Furthermore, for example, the control unit 90 monitors the execution period of the film formation process, and determines the end of the film formation process when a target execution period has elapsed (step S105: NO). The target execution period is set according to a target film thickness of the titanium oxynitride film.

[0054] When the control unit 90 determines that the film formation process is completed, it stops the supply of each gas to the processing vessel 1 and the rotation of the turntable 2, and unloads the substrate W from the processing vessel 1 in the reverse order to the order in which the substrate W was loaded (step S106). This completes the film formation method.

[0055] Fig. 5 is a graph showing the component ratios of titanium oxide films formed by the film formation method. In Fig. 5, the bar on the left side of the graph shows the concentration ratio of a titanium oxide film according to a comparative example in which ammonia gas is not supplied, and the bar on the right side of the graph shows the concentration ratio of a titanium oxide film formed by the above film formation method.

[0056] In the comparative example, oxygen gas and ozone (O3) gas were supplied as reactive gases, and a plasma treatment was performed to form a titanium oxide film on the surface of the substrate. This titanium oxide film has a titanium concentration of 35%, while the oxygen concentration is as high as 64%. In addition, in a substrate W having a plurality of recesses Wc and protrusions Ws, the oxygen concentration tends to be higher near the protruding ends of each protrusion Ws. For this reason, the titanium oxide film is likely to be formed in a shape (helmet shape) in which the film thickness is thicker at the protruding ends of the protrusions Ws.

[0057] On the other hand, in the film forming method according to the embodiment, a titanium oxynitride film is formed on the surface of the substrate W by a process of supplying a mixture of oxygen gas and ammonia gas as described above. In particular, in the film forming method, the amount of ammonia gas supplied is less than the amount of oxygen gas supplied. As a result, the titanium oxynitride film according to the embodiment has an oxygen concentration of 35.6% and a nitrogen concentration of 25%. In other words, the above film forming method can ensure the oxygen content of the titanium oxynitride film while suppressing the inclusion of a high concentration of nitrogen in the titanium oxynitride film. The titanium concentration of the titanium oxynitride film is 37.8%. In this way, the titanium oxynitride film formed by the film forming method according to the embodiment contains oxygen and nitrogen in appropriate proportions.

[0058] Furthermore, in a substrate W having a plurality of recesses Wc and protrusions Ws, the nitrogen concentration tends to be higher in the middle of each protrusion Ws. Therefore, in the film formation method, the shape of the titanium oxynitride film formed on the recesses Wc and protrusions Ws of the substrate W can be controlled by appropriately adjusting the supply amount of oxygen gas containing oxygen atoms and the supply amount of ammonia gas containing nitrogen atoms.

[0059] FIG. 6(A) is an enlarged cross-sectional view of the protruding portion Ws of the substrate W on which the film was formed. FIG. 6(B) is a graph analyzing the state of the film formed on the protruding portion Ws. In FIG. 6(A) and FIG. 6(B), the comparative example is the same as the titanium oxide film shown in the comparative example of the graph in FIG. 5, and Examples 1 to 3 are examples in which the supply amount of oxygen gas and the supply amount of ammonia gas are changed. Specifically, in Example 1, the supply amount of oxygen gas is 6000 sccm, and the supply amount of ammonia gas is 1000 sccm. Therefore, the ratio of the supply amount of ammonia gas to the supply amount of oxygen gas in Example 1 is 1 / 6. In Example 2, the supply amount of oxygen gas is 6000 sccm, and the supply amount of ammonia gas is 100 sccm. Therefore, the ratio of the supply amount of ammonia gas to the supply amount of oxygen gas in Example 2 is 1 / 60. In Example 3, the supply amount of oxygen gas is 500 sccm, and the supply amount of ammonia gas is 100 sccm. Therefore, the ratio of the supply amount of ammonia gas to the supply amount of oxygen gas in Example 3 is 1 / 5. Note that, in Examples 1 to 3, the process conditions other than the oxygen gas and ammonia gas are the same.

[0060] Moreover, the overhang in Fig. 6(B) refers to the length by which the deposited film protrudes laterally (in a direction perpendicular to the convex portion Ws) relative to the width of the protruding end of the convex portion Ws of the substrate W. The overhang ratio in Fig. 6(B) refers to the ratio of the overhang to the height direction thickness of the film deposited on the convex portion Ws of the substrate W. The bottom / top film thickness ratio in Fig. 6(B) refers to the ratio of the film thickness at the protruding end of the film deposited on the convex portion Ws of the substrate W to the film thickness at the bottom.

[0061] 6(A) and 6(B), the shape of the titanium oxynitride film formed on the protruding portions Ws of the substrate W changes by changing the supply amounts of oxygen gas and ammonia gas, or by changing the ratio between the supply amounts of oxygen gas and ammonia gas. For example, Example 1 can be said to be a pattern in which the supply amounts of oxygen gas and ammonia gas are relatively large and the supply amount ratio is small. In Example 1, it can be considered that the overhang of the protruding portions Ws of the substrate W is suppressed, and a titanium oxynitride film having a thickness relative to the faces of the protruding ends of the protruding portions Ws is formed.

[0062] On the other hand, in Example 2, the amount of oxygen gas supplied is relatively large while the amount of ammonia gas supplied is small, in other words, it can be said to be a pattern in which the ratio of supply amounts is large. In Example 2, it can be considered that a film having a generally uniform thickness is formed along the height direction of the convex portion Ws of the substrate W, with little difference in the thickness of the titanium oxynitride film (the bottom / top film thickness ratio is large).

[0063] Therefore, in the film forming method, it is preferable to adjust the supply amount of oxygen gas, the supply amount of ammonia gas, and the supply amount ratio according to the target shape of the titanium oxynitride film to be formed on the protruding portion Ws of the substrate W. For example, when forming a shape (helmet shape) in which the titanium oxynitride film is thick on the surface of the protruding end of the protruding portion Ws and thin on the side surface of the protruding portion Ws, the supply amount of ammonia gas is increased in the film forming method. That is, the ratio of the supply amount of oxygen gas to the supply amount of ammonia gas is reduced. However, even if the supply amount ratio is small as in Example 3, if the supply amounts of oxygen gas and ammonia gas are both small, the overhang becomes large.

[0064] Therefore, when forming a helmet shape, it is preferable to set the supply rates of oxygen gas and ammonia gas in the range of, for example, 1000sccm to 10000sccm. The ratio of the supply rate of ammonia gas to the supply rate of oxygen gas is preferably set in the range of about 1 / 3 to 1 / 10. This allows the helmet shape of the titanium oxynitride film to be formed with high accuracy.

[0065] On the other hand, when it is desired to obtain a film thickness that is highly uniform (conformal) over the entire surface of the protrusion Ws, the amount of ammonia gas supplied is reduced and the ratio of the amount of oxygen gas supplied to the amount of ammonia gas supplied is increased in the film forming method. For example, the ratio of the amount of ammonia gas supplied to the amount of oxygen gas supplied is set to a range of about 1 / 30 to 1 / 100. It is also preferable that the amount of oxygen gas supplied is set to a range of 1000 sccm to 10000 sccm, and the amount of ammonia gas supplied is set to a range of 10 sccm to 500 sccm. This allows a titanium oxynitride film to be formed with a conformal thickness on the protrusion Ws with high accuracy.

[0066] As described above, the film formation apparatus 100 and the film formation method are capable of forming a titanium oxynitride film in an appropriate shape on the convex portion Ws of the substrate W. In other words, the ammonia gas supplied in a mixture with oxygen gas can appropriately control the shape of the titanium oxynitride film depending on the supply amounts and the supply amount ratio of the ammonia gas and the oxygen gas.

[0067] The film forming apparatus 100 and the film forming method are not limited to the above embodiment, and may take various modifications. For example, the film forming apparatus 100 according to the above embodiment is configured to supply oxygen gas and ammonia gas to the reactive gas processing space P2 of the processing vessel 1 and cause a reaction by heating. However, the film forming apparatus 100 is not limited to this, and may be configured to generate plasma in the reactive gas processing space P2 and perform plasma processing on each substrate W. For example, the film forming apparatus 100 may include a plasma generating unit 70 at a position indicated by a dotted line in the reactive gas processing space P2 in FIG. 2. In addition, when generating plasma in the reactive gas processing space P2, the film forming apparatus 100 may contain ozone gas as a gas to be supplied to the reactive gas processing space P2 in addition to oxygen gas and ammonia gas. By converting ozone gas into plasma in the plasma generating unit 70, radicalized oxygen can be supplied to each substrate W.

[0068] Further, for example, the film forming apparatus 100 is not limited to a configuration in which the turntable 2 rotates (revolves) the multiple substrates W in the circumferential direction. For example, the film forming apparatus 100 may adopt a configuration in which each substrate W is rotated on its own axis while the turntable 2 revolves each substrate W. Furthermore, the film forming apparatus 100 may be a single-wafer type apparatus that performs a film forming process on one substrate W, or a batch type apparatus that performs a film forming process by arranging multiple substrates vertically or horizontally so that the flat surfaces of the substrates W face each other. When a single-wafer type apparatus or a batch type apparatus is applied, the same effect as above can be obtained by separating the step of supplying a titanium-containing gas (TDMAT gas) from the step of simultaneously supplying an oxidation gas (oxygen gas) and a shape control gas (ammonia gas) on the time axis.

[0069] The technical ideas and effects of the present disclosure explained in the above embodiments will be described below.

[0070] A first aspect of the present disclosure is a method for forming a titanium oxynitride film on a substrate W, comprising the steps of (a) supplying a titanium-containing gas to the substrate W, and (b) supplying an oxidizing gas to the substrate W to which the titanium-containing gas has been supplied, and supplying a shape-controlling gas to the same area as the oxidizing gas, to adjust the shape of the titanium oxynitride film.

[0071] According to the above, the film formation method can easily form a titanium oxynitride film into a target shape by supplying an oxidizing gas and a shape control gas to the same area. In addition, the titanium oxynitride film formed on the surface of the substrate W has a film quality that is softer than, for example, a titanium oxide film, and can be easily peeled off, for example. In other words, the film formation method can obtain a titanium oxynitride film that is easy to form into a target shape and is easy to process after film formation.

[0072] In the step (b), the amount of the shape-controlling gas supplied is made less than the amount of the oxidizing gas supplied, thereby making it possible for the film forming method to prevent the titanium oxynitride film from containing a high concentration of the shape-controlling gas and to ensure the oxygen content of the titanium oxynitride film.

[0073] The surface of the substrate W has a plurality of recesses Wc and a plurality of protrusions Ws formed between the recesses Wc, and in step (b), the shape of the titanium oxynitride film formed on the plurality of protrusions Ws is adjusted by changing the supply amount of the shape control gas, thereby enabling the film formation method to appropriately form the titanium oxynitride film on the plurality of protrusions Ws.

[0074] Furthermore, when the thickness of the titanium oxynitride film is made thicker on the protruding ends of the multiple protruding portions Ws and thinner on the side surfaces of the multiple protruding portions Ws, the ratio of the supply amount of the shape control gas to the supply amount of the oxidizing gas is set in the range of 1 / 3 to 1 / 10 in the step (b). This enables the film forming method to satisfactorily form a titanium oxynitride film having a certain thickness on the protruding ends of the multiple protruding portions Ws.

[0075] Furthermore, when forming a highly uniform titanium oxynitride film on the protruding ends and side surfaces of the multiple protruding portions Ws, the ratio of the supply amount of the shape control gas to the supply amount of the oxidizing gas is set in the range of 1 / 30 to 1 / 100 in the step (b), which enables the film forming method to form a titanium oxynitride film with a conformal thickness on the protruding ends and side surfaces of the multiple protruding portions Ws.

[0076] The shape-controlling gas is ammonia gas. By using ammonia gas as the shape-controlling gas, the film forming method can easily control the titanium oxynitride film to a target shape.

[0077] The oxidizing gas is oxygen gas, and the film forming method can efficiently form a titanium oxynitride film by the reaction between oxygen gas and ammonia gas in the same area (reactive gas processing space P2).

[0078] A second aspect of the present disclosure is a film formation apparatus 100 for forming a titanium oxynitride film on a substrate W, which includes a source gas supply unit 31 for supplying a titanium-containing gas to the substrate W, a reactive gas supply unit 32 for supplying an oxidizing gas to the substrate W to which the titanium-containing gas has been supplied, and a shape-controlling gas supply unit 33 for supplying a shape-controlling gas to the same area as the oxidizing gas to adjust the shape of the titanium oxynitride film. Even in this case, the film formation apparatus 100 can easily form a titanium oxide film into a target shape.

[0079] The film forming apparatus 100 also includes a processing vessel 1 and a turntable 2 rotatably provided inside the processing vessel 1 and on which a plurality of substrates W are placed, and a source gas supply unit 31 supplies a titanium-containing gas to a source gas processing space P1 set in the circumferential direction of the turntable 2, and a reactive gas supply unit 32 and a shape-controlling gas supply unit 33 supply an oxidizing gas and a shape-controlling gas to a reactive gas processing space P2 set at a position different from the source gas processing space P1 in the circumferential direction of the turntable 2. In this way, the film forming apparatus 100 can perform a film forming method while rotating each substrate W, and can satisfactorily form a titanium oxynitride film on each substrate W.

[0080] The film forming apparatus 100 and the film forming method according to the presently disclosed embodiment are illustrative and not restrictive in all respects. The embodiments can be modified and improved in various forms without departing from the spirit and scope of the appended claims. The matters described in the above embodiments can be configured in other ways without any contradiction, and can be combined without any contradiction. [Explanation of symbols]

[0081] 1 Processing vessel 2 Rotating table 31 Raw gas supply section 32 Reactive gas supply section 33 Shape control gas supply unit 100 Film deposition equipment W substrate

Claims

1. 1. A method for forming a titanium oxynitride film on a substrate, comprising the steps of: (a) supplying a titanium-containing gas to the substrate; (b) supplying an oxidation gas to the substrate to which the titanium-containing gas has been supplied, and supplying a shape-controlling gas to the same area as the oxidation gas, thereby adjusting a shape of the titanium oxynitride film. Film formation method.

2. In the step (b), the supply amount of the shape-controlling gas is made smaller than the supply amount of the oxidizing gas. The film forming method according to claim 1 .

3. the surface of the substrate has a plurality of recesses and a plurality of protrusions formed between the plurality of recesses; In the step (b), the supply amount of the shape-controlling gas is changed to adjust the shape of the titanium oxynitride film formed on the plurality of convex portions. The film forming method according to claim 1 or 2.

4. When the thickness of the titanium oxynitride film is made thicker at the protruding ends of the plurality of convex portions and thinner at the side surfaces of the plurality of convex portions, in the step (b), a ratio of the supply amount of the shape control gas to the supply amount of the oxidizing gas is set in a range of 1 / 3 to 1 / 10. The film forming method according to claim 3 .

5. When the titanium oxynitride film is formed with high uniformity on the protruding ends and side surfaces of the plurality of convex portions, in the step (b), a ratio of the supply amount of the shape control gas to the supply amount of the oxidizing gas is set in a range of 1 / 30 to 1 / 100. The film forming method according to claim 3 .

6. The shape control gas is ammonia gas. The film forming method according to claim 1 or 2.

7. The oxidizing gas is oxygen gas. The film forming method according to claim 1 or 2.

8. A film forming apparatus for forming a titanium oxynitride film on a substrate, comprising: a source gas supply unit for supplying a titanium-containing gas to the substrate; a reactive gas supply unit that supplies an oxidizing gas to the substrate to which the titanium-containing gas has been supplied; a shape-controlling gas supply unit that supplies a shape-controlling gas to the same area as the oxidizing gas to adjust the shape of the titanium oxynitride film. Film deposition equipment.

9. A processing vessel; a rotation table rotatably provided within the processing chamber and configured to place a plurality of the substrates thereon; the raw material gas supply unit supplies the titanium-containing gas to a raw material gas processing space set in a circumferential direction of the turntable; the reactive gas supply unit and the shape-controlling gas supply unit supply the oxidizing gas and the shape-controlling gas to a reactive gas processing space set at a position different from a raw material gas processing space in a circumferential direction of the turntable, The film forming apparatus according to claim 8.

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