Method for forming ruthenium film and apparatus for forming ruthenium film

Abstract

In the present invention, in a substrate processing apparatus that is provided with a mounting table which is disposed in a processing chamber and on which a substrate that is an object of film formation is placed, and an annular member which is disposed along a peripheral portion of the mounting table, a cycle which includes steps (A) to (C) executed in this order is repeated. (A) A step for placing the substrate that is an object of film formation on the mounting table and disposing the annular member on the peripheral portion of the mounting table; (B) a step for supplying a starting material gas of ruthenium into the processing chamber and forming a Ru film on the substrate; and (C) a step for supplying a cleaning gas into the processing chamber and removing the Ru film formed on the annular member in a state in which the annular member is disposed on the peripheral portion of the mounting table after the substrate on which the Ru film is formed is carried out to the outside of the processing chamber.

Description

Method for forming a ruthenium film and apparatus for forming a ruthenium film

[0001] This disclosure relates to a method for forming a ruthenium film and an apparatus for forming a ruthenium film.

[0002] In the semiconductor device manufacturing process, there is a procedure to form a ruthenium film by creating recesses such as holes and trenches in the insulating film formed on the substrate for semiconductor device manufacturing, and then embedding ruthenium (Ru), which is a wiring material, into these recesses.

[0003] Patent Document 1 discloses a technique for cleaning a reaction vessel in which a ruthenium film has been deposited on a workpiece by supplying a gas containing active oxygen as a cleaning gas. The cleaning is described as removing the ruthenium film attached to the inner wall of the reaction vessel by reducing the pressure inside the reaction vessel to 1.33 kPa or less and setting the atmosphere to a high temperature of 850°C or higher. The film deposition apparatus in Patent Document 1 is a vertical heat treatment apparatus in which a large number of workpieces are placed in multiple stages on a wafer boat and transported into the reaction vessel. Patent Document 1 does not describe a single-wafer film deposition apparatus in which the workpieces are placed on a mounting table and the film is deposited.

[0004] Japanese Patent Publication No. 2003-13232

[0005] This disclosure provides a technique for removing a ruthenium film formed on an annular member positioned at the periphery of a mounting stage when a substrate is placed on the mounting stage to deposit a ruthenium film.

[0006] This disclosure relates to a method for forming a ruthenium film on a substrate, comprising a substrate processing apparatus which is placed in a processing container and on which a substrate to be formed is placed, and an annular member which is placed along the periphery of the aforementioned platform during the period in which the film is formed, the method comprising: (A) a step of placing the substrate to be formed on the aforementioned platform and the annular member being placed on the periphery of the platform; (B) a step of supplying a ruthenium raw material gas into the processing container and forming a ruthenium film on the substrate; and (C) a step of supplying a cleaning gas into the processing container with the annular member being placed on the periphery of the aforementioned platform after the substrate on which the ruthenium film has been formed has been removed from the processing container and the ruthenium film formed on the annular member has been removed, wherein the steps (A) to (C) are performed in this order in a repeating cycle.

[0007] According to this disclosure, when a substrate is placed on a mounting stage in a processing container to form a ruthenium film, the ruthenium film formed on an annular member arranged at the periphery of the mounting stage can be removed.

[0008] This is a plan view showing one embodiment of a substrate processing system. This is a longitudinal cross-sectional side view showing one embodiment of a film deposition apparatus. This is a plan view and a side view showing a part of the film deposition apparatus. This is an explanatory diagram showing a state in which a ruthenium film has been formed on an annular member (clamp ring). This is a flowchart showing one embodiment of a film deposition method. This is an explanatory diagram showing the state of the annular member (clamp ring) during the execution period of the film deposition method. This is a longitudinal cross-sectional side view showing a part of another embodiment of the film deposition apparatus. This is a first characteristic diagram showing experimental results. This is a second characteristic diagram showing experimental results. This is a third characteristic diagram showing experimental results.

[0009] <Substrate Processing System> Figure 1 is a schematic plan view illustrating a substrate processing system according to the present disclosure, which includes a substrate processing apparatus (hereinafter referred to as "film deposition apparatus") for depositing a ruthenium film. The substrate processing system 1 is a multi-chamber system equipped with a plurality of processing modules 11, 12, and 13, including a processing module for depositing a ruthenium film (Ru film) on a semiconductor wafer 10 (hereinafter referred to as "wafer 10") which is a substrate. In this example, the substrate processing system 1 will be described as an example in which a Ru film is deposited in a recess formed on the surface layer of the wafer 10 so as to be embedded in the recess. For example, the wafer 10 has a tungsten layer (W layer) and, for example, a silicon oxide film (SiO ２ An insulating layer is laminated with this insulating layer, and multiple recesses are formed in this insulating layer by etching.

[0010] In the substrate processing system 1, in this example, processing module 11 is configured as a pre-cleaning module, processing module 12 as a film deposition module, and processing module 13 as an annealing module. Hereinafter, these processing modules 11 to 13 will also be referred to as "pre-cleaning module 11, film deposition module 12, and annealing module 13." Film deposition module 12 is a module corresponding to the film deposition apparatus of this disclosure, and is configured to supply ruthenium (Ru) raw material gas into the processing container and deposit a Ru film on the wafer 10, the details of which will be described later. Pre-cleaning module 11 is a module that performs a pre-cleaning process to remove the metal oxide film formed on the bottom wall of the recess before the Ru film deposition process. Annealing module 13 is a module that performs an annealing process on the Ru film after the Ru film deposition process.

[0011] Returning to the explanation of Figure 1, the substrate processing system 1 is provided with a loader module 14, a load lock module 15, a first vacuum transport module 16, a connection module 17, and a second vacuum transport module 18 arranged in this order in the front-to-back direction (Y direction in Figure 1) when viewed from above. In the following explanation of the substrate processing system 1, the direction perpendicular to the front-to-back direction is referred to as the left-to-right direction (X direction in Figure 1), and in the front-to-back direction, the side where the loader module 14 is located is referred to as the front side, and the side where the second vacuum transport module 18 is located is referred to as the rear side.

[0012] The loader module 14 is set to an atmospheric pressure environment and is configured to transport wafers 10 between the transport container C and the load lock module 15 by a transport mechanism 141 located inside it. The transport container C is placed on the load port 142 and contains a large number of wafers 10 with recesses formed on their surfaces. The load lock module 15 is a module that transfers wafers 10 between the loader module 14 and the first vacuum transport module 16, and its interior is configured to be adjustable to atmospheric pressure and the pressure inside the first vacuum transport module 16.

[0013] The first and second vacuum transport modules 16 and 18 are similarly configured and each includes a first and second vacuum transport mechanism 191 and 192, respectively. These modules 16 and 18 are maintained in a vacuum atmosphere by a vacuum evacuation mechanism connected via an exhaust pipe, but the exhaust pipe and vacuum evacuation mechanism are not shown in the illustration. Hereafter, the first and second vacuum transport mechanisms 191 and 192 may be referred to as the vacuum transport mechanism 19. The connecting module 17 is a module that transfers wafers 10 between the first and second vacuum transport modules 16 and 18, and is adjusted to the same vacuum atmosphere pressure as inside the first and second vacuum transport modules 16 and 18.

[0014] On both the left and right sides of the first vacuum transport module 16, when viewed from the front, a cleaning module 11 and a film deposition module 12 are provided, arranged front to back. The first vacuum transport mechanism 191 is configured to transport the wafer 10 between these processing modules 11 and 12, a connection module 17, and a load lock module 15. Similarly, on both the left and right sides of the second vacuum transport module 18, when viewed from the front, a film deposition module 12 and an annealing module 13 are provided, arranged front to back. The second vacuum transport mechanism 192 is configured to transport the wafer 10 between these processing modules 12 and 13 and a connection module 17.

[0015] A wafer transport port is formed between the first and second vacuum transport modules 16 and 18 and the processing modules 11, 12, and 13, respectively, and these transport ports are configured to be opened and closed by gate valves GV. Note that wafer transport ports and gate valves for opening and closing these ports also exist between the first and second vacuum transport modules 16 and 18 and the transfer module 17, between the load lock module 15 and the first vacuum transport module 16, and between the load lock module 15 and the loader module 14, but these are not shown in the illustration.

[0016] The substrate processing system 1 includes a control unit 100, which is a computer, and this control unit 100 contains a program. The program incorporates instructions (steps) for performing the process of depositing a Ru film on the wafer 10 (described later) and each step in the transport of the wafer 10. This program is stored in a storage medium, such as a compact disk, hard disk, DVD, or non-volatile memory, and is read from the storage medium and installed in the control unit 100.

[0017] The control unit 100 is configured to output control signals to each part of the substrate processing system 1 according to the program, thereby executing the operation of each part. Specifically, it controls the operation of processing modules 11 to 13, the opening and closing of gate valves GV, the operation of the transport mechanism 141 and the first and second vacuum transport mechanisms 191 and 192, and the operation of the exhaust mechanism. Control of the operation of the processing modules 11 to 13 includes, for example, temperature control of the wafer 10 by supplying power to the heating section, and control of the supply and cutoff and supply flow rate of each gas in each processing module 11 to 13.

[0018] <Film Deposition Module> Next, an example of the configuration of the film deposition module 12 will be described with reference to Figure 2. Figure 2 shows the film deposition module 12 connected to the right side of the first and second vacuum transport modules 16 and 18, as viewed from the loader module 14 side in Figure 1. This film deposition module 12 is configured to deposit a Ru film by thermal CVD using a raw material gas containing Ru. The film deposition module 12 comprises a processing container 2, a mounting table 3 provided inside the processing container 2, and a gas shower head 4 provided above the processing container 2 so as to face the mounting table 3, for introducing the raw material gas into the processing container 2.

[0019] The processing container 2 comprises a lower container 22 that encloses a lower space and has an opening at the top, and an exhaust duct 21 stacked on the upper end of the side wall of the lower container 22. The opening surrounded by the exhaust duct 21 is closed from above by a gas shower head 4 and a support member 41 for the gas shower head 4, thus forming the processing container 2. The lower container 22 and the exhaust duct 21 are made of, for example, aluminum (Al). An inlet / outlet 20 for loading and unloading wafers 10 by the first and second vacuum transport mechanisms 191 and 192 described above is formed in the side wall of the lower container 22, and this inlet / outlet 20 is opened and closed by the gate valve GV described above.

[0020] The exhaust duct 21 is configured as an annular body formed by curving a duct with a rectangular cross-sectional shape, for example, and has multiple openings 211 on its inner circumferential surface. The outer circumferential wall of the exhaust duct 21 is connected to the exhaust mechanism 23 via an exhaust pipe 231, and is configured to evacuate the inside of the processing container 2. The exhaust mechanism 23 includes, for example, a vacuum pump and a pressure regulating valve such as an APC valve.

[0021] The mounting table 3 is formed in the shape of a flat disc, using a material such as aluminum nitride (AlN) or quartz, and has a heater 31 embedded inside that serves as a heating element for raising the wafer 10 to a preset temperature. The heater 31 is powered by a power supply unit (not shown) to heat the wafer 10 placed on the mounting table 3 to a temperature within the range of 100°C to 250°C, which is the film deposition temperature for Ru, for example.

[0022] In this example, the mounting base 3 is covered by a cover member 32 made of, for example, quartz. The cover member 32 is positioned to detachably cover the top and sides of the mounting base 3, preventing reaction products and by-products such as Ru from accumulating on the surface of the mounting base 3. A circular recess 321 having a diameter slightly larger than the wafer 10 is formed in the central region of the top surface of the cover member 32, and this recess 321 constitutes the mounting surface of the mounting base 3. In addition, a through hole is formed on the top side of the cover member 32 for housing the head of the lifting pin 37, which will be described later.

[0023] The lower central part of the mounting platform 3 is supported by a columnar support member 33, the lower end of which penetrates the bottom of the processing container 2 and is connected to a lifting plate 35 that is raised and lowered by a lifting mechanism 34. Furthermore, the space between the lifting plate 35 and the bottom wall of the lower container 22 is airtightly joined by a bellows 36. In this way, the mounting platform 3 is configured to be able to move up and down between a transport position (shown by a dashed line in Figure 2) where the wafer 10 is transferred between the first and second vacuum transport mechanisms 191 and 192, and a processing position (shown by a solid line in Figure 2) located above the transport position where the wafer 10 is processed.

[0024] Furthermore, the mounting table 3 is equipped with, for example, three lifting pins 37 for transferring the wafer 10. These lifting pins 37 penetrate the mounting table 3 vertically, with their lower ends protruding downward from the mounting table 3. A ring-shaped lifting member 38 is provided below each lifting pin 37. By lowering the mounting table 3 to the wafer 10 transport position and then raising and lowering the lifting member 38, the wafer 10 supported by the lifting pins 37 can be placed on and raised against the mounting surface of the mounting table 3.

[0025] The processing container 2 is provided with an inner ring 24 that surrounds the mounting platform 3 of the processing position. The inner ring 24 is an annular member made of, for example, aluminum (Al), and is provided on the side wall of the lower container 22. For example, a flange portion 241 is provided on the outer circumference of the upper surface of the inner ring 24 so as to widen outwards, and the inner ring 241 is positioned inside the processing container 2 with the flange portion 241 locked to the exhaust duct 21.

[0026] Furthermore, an annular member is arranged inside the processing container 2 along the periphery of the mounting table 3. In this example, the annular member is a clamping ring 5, which is provided to contact the periphery of the upper surface of the wafer 10 placed on the mounting table 3 and cover the periphery. The clamping ring 5 has the function of fixing the wafer 10 to the mounting table 3 and preventing the Ru raw material gas from flowing inwards towards the lower side of the mounting table 3.

[0027] For example, as shown in Figures 3(a) and 3(b), the clamp ring 5 comprises a main body 51 made of an annular plate material, and is positioned inside the processing container 2 with the lower surface of the outer edge of the main body 51 resting on the inner ring 24. The inner edge of the main body 51 extends substantially horizontally toward the center of the processing container 2, and its inner end is located above the peripheral edge of the wafer 10 placed on the mounting table 3. The inner end of the main body 51 is bent downward, and a flat contact portion 52 is formed at its lower end. The clamp ring 5 is made of, for example, alumina (Al ２ O ３ It is composed of ceramics such as ) and metals such as Al.

[0028] When the mounting table 3 rises to the processing position, the clamping ring 5's contact portion 52 contacts the entire circumference of the peripheral edge of the wafer 10 on the mounting table 3, pressing down on the wafer 10. In this way, when the contact portion 52 of the clamping ring 5 is in a position to press down on the peripheral edge of the wafer 10, the main body portion 51 is positioned from the peripheral edge of the wafer 10 to the side wall of the processing container 2. As a result, the clamping ring 5, together with the mounting table 3 in the processing position, is configured to divide the inside of the processing container 2 into the processing space S1, which is the space above the mounting table 3, and the lower space S2 described above. By pressing its contact portion 52 against the wafer 10 on the mounting table 3, the clamping ring 5 suppresses the leakage of raw material gas into the lower space S2 of the processing container 2, preventing the formation of a Ru film on the peripheral edge or back surface of the wafer 10. Therefore, the clamp ring 5 is configured to have a weight sufficient to suppress the leakage of the raw material gas, for example, a weight of several hundred grams to several kilograms.

[0029] Next, the gas shower head 4 will be described. The gas shower head 2 is disc-shaped and is provided on the lower surface of the support member 41. For example, the lower surface of the peripheral edge of the gas shower head 4 is positioned above the clamp ring 5 and opposite the clamp ring 5. A gas diffusion space (not shown) is provided inside the gas shower head 4, and the lower part of the gas shower head 4 is a shower plate with multiple through holes formed therein. The upper center of the gas shower head 4 is connected to the gas supply mechanism 6 via the support member 41.

[0030] The gas supply mechanism 6 is configured to supply various processing gases to the processing container 2. Specifically, the gas supply mechanism 6 includes a raw material gas supply unit 61 for supplying raw material gas for forming a Ru film, an ozone gas supply unit 62 for supplying etching gas and cleaning gas, a reducing gas supply unit 63, and a gas supply pipe 64 that branches to connect each of the supply units 61 to 63 to the gas shower head 4. The raw material gas supply unit 61 includes a raw material gas supply source 611 for the Ru film, a flow meter 612, and a valve V1, which are arranged in this order downstream in the branched gas supply pipe 64. In this example, Ru is used as the raw material gas for the Ru film. ３ (CO)１２ It uses (DCR: dodecacarbonyltriruthenium) gas, and the raw material gas supply unit 61 is configured to generate DCR gas using, for example, carbon monoxide (CO) gas as a carrier gas.

[0031] The ozone gas supply unit 62 includes an oxygen (O ２ ) gas supply source ２ 621, valve V21, flow rate adjustment unit 622, ozonizer 623, and valve V22, and these are arranged in this order downstream in the branched gas supply pipe 64. The O ２ gas supplied from the oxygen gas supply source ２ 621 is controlled in flow rate by the flow rate adjustment unit 622 and supplied to the ozonizer 623. The ozonizer 623 is configured as, for example, a silent discharge type discharge tube, and discharges by the electric energy applied from an external power source not shown in the figure, and activates at least a part of the supplied O ２ gas to supply ozone (O ３ ) gas. And the ozonizer 623 adjusts the applied voltage from the external power source to adjust the O ３ concentration, for example, from 0 g / m ３ to 400 g / m ３ (based on 0 °C, 101.3 kPa. Hereinafter, the same applies to the O ３ concentration). Thus, the ozonizer 623 is configured to be able to supply ozone-containing oxygen gas with different O ３ concentrations. Also, by adjusting both the supply flow rate of the O ２ gas from the oxygen gas supply source ２ 621 and the applied voltage, it is possible to change the supply flow rate of the O ３ gas while maintaining the desired O ３ concentration.

[0032] In this example, as will be described later, the process of forming the Ru film involves supplying a raw material gas to form the Ru layer and etching a portion of the Ru layer using an etching gas. The etching gas used at this time is a gas containing ozone. The cleaning gas used in the process of removing the Ru film formed on the annular member, the clamp ring 5, is also a gas containing ozone. However, the etching gas and the cleaning gas are defined as gases containing O ３ The concentrations are different, and the cleaning gas is O200% higher than the etching gas. ３ High-concentration gases are used.

[0033] In this disclosure, the ozonizer 623 uses O as the etching gas. ３ Concentration of 100 g / m² ３ Above, 400g / m ３ For example, within the range of less than O ３ Concentration 150g / m ３ It supplies ozone-containing oxygen gas. In addition, as a cleaning gas, O ３ Concentration of 100 g / m² ３ Above, 400g / m ３ Within the following range, the ozone concentration is higher than that of the ozone-containing oxygen gas supplied as the etching gas, for example, O ３ Concentration 300g / m ３ Ozone-containing oxygen gas is supplied. Therefore, the ozone gas supply unit 62 corresponds to the cleaning gas supply unit. Oxygen gas supplied from the oxygen gas supply source 621 to the ozonizer 623. ２ The gas flow rate for both the etching gas and the cleaning gas is, for example, 400 sccm to 20,000 sccm.

[0034] The reducing gas supply unit 63 includes a supply source 631 for reducing gas, such as CO gas, a flow rate adjustment unit 632, and a valve V3. As will be described later, in the ruthenium film deposition process, Ru ３ (CO) １２To regulate the decomposition, CO gas is supplied separately from the carrier gas, in parallel with the raw material gas. The reducing gas supply unit 63 supplies the aforementioned CO gas in parallel with the raw material gas during the film formation process, and also supplies CO gas together with the cleaning gas during the cleaning process. Furthermore, the gas supply mechanism 6 preferably includes an inert gas supply unit connected to the gas shower head 4, similar to the supply units 61 to 63 for each processing gas. In this case, the supplied inert gas purges each processing gas and suppresses the reaction between the processing gases and the accumulation of products.

[0035] Furthermore, in this example, the processing container 2 and the gas shower head 4 are each provided with a processing container heating section 71 and a gas shower head heating section 72. These processing container heating sections 71 and gas shower head heating sections 72 are configured to heat the constituent members of the processing container 2 and the gas shower head 4 in order to prevent the formation of a Ru film on their surfaces. For example, the processing container heating section 71 is made up of heaters provided on the side walls and bottom walls of the processing container 2, and the gas shower head heating section 72 is made up of heaters provided on the support member 41.

[0036] A brief explanation will also be given of the processing modules other than the film deposition module 12 in the substrate processing system 1. The pre-clean module 11 is a device that supplies H between the gas shower head and the mounting table. ２ The system is configured to supply plasma to the wafer 10 to remove the metal oxide film formed in the recesses. The bottom surface of the recesses, as described above, exposes a tungsten oxide film that has been oxidized by, for example, an atmospheric environment. Therefore, the pre-clean module 11 performs a process to remove the metal oxide film (tungsten oxide film) from the bottom surface of the recesses. Furthermore, the annealing module 13 uses, for example, N ２ The system is configured to heat the wafer 10 placed on the mounting platform while supplying an inert gas such as gas.

[0037] In the substrate processing system 1 having the above configuration, the first and second vacuum transport modules 16 and 18 are kept in a vacuum atmosphere with a preset pressure, and the processing modules 11 to 13 each regulate the pressure inside the processing container 2 to a preset vacuum atmosphere using an exhaust mechanism. Furthermore, in each processing module 11 to 13, the mounting stage 3 is preheated to, for example, 200°C.

[0038] Then, the wafer 10 is transported in the following order: transport container C → loader module 14 → load lock module 15 → first vacuum transport module 16 → pre-clean module 11 to remove the metal oxide film formed on the bottom wall of the recess of the wafer 10. Next, the wafer 10 is transported in the following order: first vacuum transport module 16 → film deposition module 12. When transporting to the film deposition module 12 on the second vacuum transport module 18 side, the wafer 10 is transported in the following order: first vacuum transport module 16 → connection module 17 → second vacuum transport module 18 → film deposition module 12.

[0039] Thus, a Ru film is deposited on the wafer 10 in the film deposition module 12, and then the wafer 10 is transported to the annealing module 13 via the second vacuum transport module 18. After that, the wafer 10 is transported in the following order: second vacuum transport module 18 → connection module 17 → first vacuum transport module 16 → load lock module 15 → loader module 14, and returned to the transport container C.

[0040] In this process, the film deposition module 12 transfers the wafer 10 to the mounting table 3 using the first and second vacuum transfer mechanisms 191 and 192, as described later. Then, with the clamp ring 5 positioned around the periphery of the wafer 10, the raw material gas is supplied to the processing space S1 to perform the Ru film deposition process. Incidentally, in the past, in order to standardize the environment inside the processing container 2 during film deposition and to perform stable film deposition, the processing container 2 was sometimes coated with a Ru film. However, as the number of Ru film deposition processes in the processing container 2 increases, the Ru film formed on the clamp ring 5 gradually accumulates, which can cause film peeling on the clamp ring 5 and lead to particle generation. Furthermore, there is a concern that the uniformity of the film deposition process cannot be maintained due to changes in the state of the Ru film formed on the clamp ring 5.

[0041] One of the factors that can be assumed to cause particle generation is the increasing thickness of the Ru film deposited on the clamp ring 5. As the film thickness increases, it becomes easier for the film to peel off, and it is presumed that this peeling off is what causes the generation of particles. Another factor that can be assumed is that, as shown in Figure 4(b-1), a layered structure of Ru81 and ruthenium oxide (RuOx)82 is formed on the surface of the clamp ring 5 during the film deposition process described later. Figure 4(a) shows the clamp ring 5 before the film deposition process is performed. As will be described later, the film deposition process involves repeatedly depositing a Ru layer and etching a part of the Ru layer, and during this etching, the Ru layer is oxidized to form RuOx82. Therefore, as the deposition and etching of the Ru layer are repeated, a layered structure of Ru81 and RuOx is formed, but because these have low adhesion to each other, film peeling is likely to occur at their interface, and it is presumed that this peeling off is what causes the generation of particles.

[0042] Furthermore, the factors contributing to the decrease in uniformity of the film deposition process are speculated as follows: As shown in Figure 4(b-2), it is thought that RuOx82 is partially formed on the surface of Ru81 formed on the clamp ring 5. In the film deposition process described later, the raw material gas for Ru contains CO gas as a carrier gas, and as previously mentioned, CO gas for reaction adjustment is supplied in parallel with the raw material gas. However, these CO gases are consumed in the reduction of RuOx82 formed on the clamp ring 5, accelerating the decomposition of the raw material gas. As a result, the amount of raw material gas supplied becomes uneven on the wafer surface between the vicinity of the region where RuOx82 is formed and the vicinity of the region where it is not formed. As a result, it is speculated that the in-plane uniformity of the film deposition rate of the wafer 10 decreases.

[0043] For these reasons, in this disclosure, after the step of depositing a Ru film on the wafer 10, a step of removing the Ru film formed on the clamp ring 5 using a cleaning gas is performed. The Ru film deposition method of this disclosure will be described in detail below with reference to Figure 5, which shows a flowchart, and Figure 6, which shows the state of the clamp ring 5. The Ru film deposition process of this disclosure is carried out by repeating a cycle in the deposition module 12 in the order of placement step (A), deposition step (B), and cleaning step (C) multiple times.

[0044] First, a placement step (A) is performed in which the wafer 10 is brought into the processing container 2 and placed on the mounting table 3, so that the clamp ring 5 is positioned on the periphery of the mounting table 3 (step S1). In this placement step (A), the film deposition module 2 uses a vacuum transfer mechanism 19 (191, 192) to bring the wafer 10 into the processing container 2 and transfer it to the mounting table 3 at the transfer position. Next, the vacuum transfer mechanism 19 is withdrawn from the processing container 2 and the gate valve GV is closed, moving the mounting table 3 to the processing position. In this way, the clamp ring 5 is positioned so that the contact portion 52 contacts the entire periphery of the wafer 10, and the clamp ring 5 is positioned on the periphery of the mounting table 3.

[0045] Next, a Ru raw material gas is supplied into the processing container 2 to perform a film deposition process (B) in which a Ru film is deposited on the wafer 10 (step S2). This film deposition process (B) is performed by repeating a cycle multiple times in which a Ru layer deposition process (B-1), in which a ruthenium layer (Ru layer) is deposited using a raw material gas, and an etching process (B-2), in which a part of the Ru layer is etched using an etching gas, are performed in this order.

[0046] In the Ru layer deposition process (B-1), for example, the wafer 10 placed on the mounting table 3 is heated to a predetermined temperature, and the pressure in the processing space S1 is adjusted to a set pressure. In addition, the processing container heating unit 71 and the gas shower head heating unit 72 heat the components of the processing container 2 and the gas shower head 4 to a temperature lower than the temperature that suppresses Ru film deposition, for example, the lower limit of the film deposition temperature range (100 to 250°C). Then, the raw material gas supply unit 61 supplies DCR gas, which is the raw material gas for Ru, together with the carrier gas CO gas into the processing space S1, and the reduction gas supply unit 63 supplies CO gas for reaction adjustment. Note that an inert gas, such as argon (Ar) gas, is supplied to the processing space S1 from an inert gas supply unit (not shown), and purge gas is continuously supplied to the lower space S2 from a purge gas supply mechanism (not shown).

[0047] As a result, the DCR gas decomposes on the heated surface of the wafer 10, and a Ru layer is formed on the surface of the wafer 10 by thermal CVD. During this process, Ru layers are deposited at the bottom and sides of the recesses. Specifically, the Ru layer is formed by deposition (bottom-up) from the bottom of the recess upwards. Additionally, ruthenium is deposited in island-like formations from the sides of the recesses.

[0048] In this case, DCR gas is supplied together with CO gas. DCR (Ru ３ (CO) １２ ) is Ru(CO) ４ YaRu(CO) ５ It is broken down into Ru through this process, but Ru(CO) ５ is Ru(CO) ４ It is more stable and less susceptible to thermal decomposition. DCR gas undergoes Ru(CO) decomposition in the presence of CO gas. ５This makes it easier for the CO gas to decompose the Ru raw material gas in the gas supply pipe 64, the gas shower head 4, and the processing space S1, thus playing a role in suppressing the deposition of Ru outside of the wafer 10.

[0049] An example of the processing conditions for the Ru layer deposition process (B-1) is as follows: pressure inside the processing vessel: 2.21 Pa (16.6 mTorr), temperature of the mounting stage: 155°C or 180°C, DCR gas flow rate: 1.6 to 2.0 sccm, CO gas flow rate: 200 to 300 sccm. In the Ru layer deposition process (B-1), depending on the desired thickness of the Ru film, the deposition process (B-1) may be divided into multiple cycles and repeated, for example, 3 to 5 times. An example is when the execution time of the deposition process (B-1) per cycle (DCR gas supply time) is 35 seconds. When the deposition process (B-1) is repeated for multiple cycles in this way, for example, the supply of DCR gas is stopped and the supply of CO gas is continued, and a DCR purge is performed for 5 seconds. Next, the supply of CO gas is stopped, while the exhaust from the processing container 2 is continued. After this exhaust is maintained for, for example, 10 to 60 seconds, the DCR gas supply for the next cycle is carried out.

[0050] After performing the Ru layer deposition process (B-1) for a predetermined time, the etching process (B-2) is carried out. This process is performed to prevent the opening of the recess from closing and voids from forming as the thickness increases due to further deposition of Ru on the side of the recess.

[0051] Specifically, the supply of DCR gas and CO gas is stopped, and as etching gas, for example, O is supplied from the ozone gas supply unit 62. ３ Concentration 150g / m ３ Ozone-containing oxygen gas is supplied. This causes the surface portion of the Ru layer at the bottom of the recess and the Ru on the sides to separate. ３ It reacts with gas to form volatile ruthenium tetroxide (RuO ４) and are exhausted and removed by the exhaust mechanism 23. An example of the processing conditions for the etching process (B-2) is as follows: pressure inside the processing vessel: 2.21 Pa (16.6 mTorr), mounting stage temperature: 155°C or 180°C, etching gas flow rate: 1000 sccm, and time for performing the etching process (B-2) (time for supplying etching gas): 25 sec. However, as will be described later, the pressure inside the processing vessel and the mounting stage temperature may be set to different values ​​than those for the Ru layer deposition process (B-1).

[0052] The Ru film deposition process (B) is completed by repeating the Ru layer deposition process (B-1) and the etching process (B-2) in this order a predetermined number of times (steps S2, S3). For example, in the deposition process (B), the cycle of processes (B-1) and (B-2) is repeated four times to deposit a Ru film with a thickness of approximately 50 nm. The total processing time for the deposition process (B) is, for example, 1500 seconds. After completing the deposition process (B), the mounting table 3 is lowered to the transport position. Then, the gate valve GV is opened to transfer the wafer 10 from the mounting table 3 to the first and second vacuum transport mechanisms 191 and 192, and the wafer 10 is removed from the processing container 2 (step S4).

[0053] Next, a cleaning process (C) is performed. In this process, the mounting table 3 is raised to the processing position, and with the clamp ring 5 positioned around its periphery, a cleaning gas is supplied into the processing container 2 to remove the Ru film formed on the clamp ring 5 (Step S5). As previously described, CO gas is supplied along with the DCR gas to suppress the deposition of Ru film in areas other than the wafer 10. In addition, the processing container 2 is heated by the processing container heating section 71 and the gas shower head heating section 72, so the deposition of Ru film on the components of the processing container 2 and the gas shower head 4 is suppressed.

[0054] In contrast, the clamping ring 5 presses against the wafer 10 during the film deposition process, is located near the wafer 10, and is heated to a temperature suitable for Ru film deposition by heat transfer from the mounting table 3 through the wafer 10. Therefore, when the film deposition process (B) is carried out, a Ru film is deposited on the surface of the clamping ring 5, just as a Ru film is deposited on the wafer 10. Figure 6 schematically shows the state of the clamping ring 5 during the film deposition process. Figure 6(a) shows the state after the placement process (A) is completed and before the film deposition process (B) is started, and Figure 6(b) shows the state after the film deposition process (B) is completed. As shown in Figure 6(b), at the stage when the film deposition process (B) is completed, a Ru film 8 is formed on the surface of the clamping ring 5.

[0055] Therefore, as shown in Figure 6(c), in the cleaning step (C), ozone-containing oxygen gas, which is a cleaning gas, is supplied into the processing container 2 to remove the Ru film 8 formed on the clamp ring 5. In the cleaning step (C) of this example, a reducing gas (CO gas in this example) is supplied to assist in the removal of the Ru film 8 by the cleaning gas, and cleaning is performed.

[0056] Furthermore, the cleaning gas supplied in the cleaning process (C) has a higher O250% ratio to the processing container 2 than the etching gas described above. ３ The supply volume is set to be large. In the etching process (B-2), a portion of the Ru layer is etched, but in this cleaning process (C), the Ru film 8 deposited on the clamp ring 5 is removed. Therefore, the Ru film 8 to be removed is thicker, and a larger etching rate is required in the cleaning process (C).

[0057] Specifically, the pressure inside the processing container 2 is adjusted to be higher than the pressure used during etching, and the supply flow rate of the cleaning gas, which is ozone-containing oxygen gas, is adjusted to be greater than the supply flow rate of the etching gas, which is ozone-containing oxygen gas. Furthermore, the O in the cleaning gas ３ The concentration of O in the etching gas ３ The concentration is adjusted to be higher than the standard. O for these processing containers 2 ３Adjustments to increase the supply will be implemented by selecting at least one of these options.

[0058] Furthermore, in the cleaning process (C), it is preferable to adjust the temperature so that the heating temperature of the mounting table 3 by the heater 31 is lower than in the etching process (B-2). This is because, as shown in the experimental examples described later, the amount of etching of the Ru film in the cleaning process (C) is greater when the temperature of the mounting table 3 is around 80°C. However, it has also been found from the experimental examples that the temperature dependence of the etching amount of the Ru film differs depending on the type of reducing gas. For this reason, the heating temperature of the mounting table 3 should be adjusted according to the type of reducing gas and the processing, and the cleaning process (C) may be performed at approximately the same temperature as the etching process (B-2) in order to prioritize processing throughput.

[0059] Here is an example of the processing conditions for the cleaning process (C): As a cleaning gas, O ３ For example, a concentration of 100-400 g / m³ ３ Ozone-containing oxygen gas is used. The processing container pressure is 13.3 to 933 Pa (0.1 to 7 Torr), the mounting platform temperature is 60 to 250°C, and the cleaning gas flow rate is (O ２ Gas flow rate): Set to 400 to 20000 sccm. This cleaning process (C) removes the Ru film 8 formed on the surface of the clamp ring 5. ３ Reacts with gas to form RuO ４ After vaporizing, it is removed by exhaust from the exhaust mechanism 23 (see Figure 6(c)).

[0060] As the cleaning process (C) continues in this manner, O is produced on the surface of the Ru film 8. ３ gas and O ２ Ruthenium oxide (RuO) reacts with gas ２ Ruthenium dioxide may be formed. ２ O ３ RuO ４Although it is removed, its etching rate is lower compared to the unoxidized Ru film 8. For this reason, in this example, a cycle of alternately supplying cleaning gas and CO gas, which is a reducing gas, is repeated.

[0061] Specifically, cleaning gas is supplied from the ozone gas supply unit 61 for a predetermined period, then the supply of cleaning gas is stopped, and then CO gas is supplied from the reduction gas supply unit 63. As a result, the ruthenium oxide formed on the surface side of the Ru film 8 is reduced by the CO gas, resulting in an unoxidized Ru film. Then, after supplying CO gas for a predetermined period, the supply of CO gas is stopped, and then cleaning gas is supplied again from the ozone gas supply unit 62. Since an unoxidized Ru film is deposited on the clamp ring 5, the removal of the Ru film by the cleaning gas proceeds rapidly.

[0062] Here, CO gas was used as the reducing gas, but in addition to this, hydrogen (H) can also be used as a reducing gas. ２ ) gas or its plasma, ammonia (NH ３ ) gas or its plasma, monomethylhydrazine ((CH ３ ) (NH) NH ２ ) gas, hydrazine (N ２ H ４ A group of reducing gases consisting of the following gases can be selected. Furthermore, multiple gases selected from these may be supplied simultaneously or alternately.

[0063] The CO gas supply conditions are: pressure inside the processing vessel: 13.3 Pa to 2.66 kPa (0.1 to 20 Torr), mounting stage temperature: 60 to 250°C, and CO gas flow rate: 300 to 20000 sccm. In addition, H is used as the reducing gas. ２ When using gas, the supply conditions are: pressure inside the processing container: 13.3 to 933 Pa (0.1 to 7 Torr), mounting platform temperature: 60 to 250°C, H ２ The gas flow rate is 100 to 20,000 sccm. As such, the supply conditions for the reducing gas are selected as appropriate, but from the viewpoint of suppressing a decrease in throughput, it is preferable to match the pressure inside the processing vessel and the temperature of the mounting stage with the conditions when the cleaning gas is supplied.

[0064] In this way, the Ru film 8 is removed in the cleaning process (C) by repeatedly performing a cycle of alternately supplying cleaning gas and reducing gas. The supply time for the cleaning gas is, for example, 25 seconds, and the supply time for the reducing gas is, for example, 120 seconds. The conditions and cleaning times for the cleaning process (C) described above should be determined in advance through experiments. Here, the Ru film deposited on the clamp ring 5 is removed in the cleaning process (C), but in the film formation process (B), the Ru film deposited in locations other than the clamp ring 5 in the processing container 2 is also removed.

[0065] After completing the cleaning process (C), the processing container 2 is purged, for example, with an inert gas. Next, the film deposition module 12 loads the next wafer 10 that has not yet undergone film deposition (placement process (A)), and performs the film deposition process (B) and the cleaning process (C) on the wafer 10. In this way, the film deposition module repeatedly performs a cycle in which the placement process (A), the film deposition process (B), and the cleaning process (C) are executed in this order.

[0066] In the above, cleaning gas and reducing gas were supplied alternately in cleaning step (C), but cleaning gas and reducing gas may be supplied simultaneously. That is, in cleaning step (C), cleaning gas may be supplied from the ozone gas supply unit 62 and reducing gas may be supplied from the reducing gas supply unit 63. In this case, as will be clear from the embodiments described later, the effect of further increasing the etching rate of the Ru film is obtained.

[0067] In this embodiment, after the wafer 10 on which the Ru film has been deposited is removed from the processing container 2, the clamp ring 5 is placed on the periphery of the mounting table 3 to remove the Ru film formed on the clamp ring 5. Therefore, by performing the film deposition process stably, the uniformity of the film deposition process can be improved and the generation of particles can be suppressed.

[0068] In other words, as shown in Figure 6, when the film deposition process (B) is completed, the Ru film 8 is deposited on the clamp ring 5 (Figure 6(b)), but the Ru film 8 is removed by performing the cleaning process (C) (Figure 6(c)). Then, in this state, the film deposition process (B) is performed on the next wafer 10 (Figure 6(a)). Thus, when the Ru film deposition process is performed on the wafer 10, the Ru film 8 is not formed on the clamp ring 5.

[0069] Therefore, the environment surrounding the wafer 10 during the film deposition process can be standardized for each process, and variations in conditions from process to process can be suppressed. As a result, process stability is improved and the uniformity of the process is enhanced. The clamp ring 5 is positioned around the wafer 10 and has a significant impact on the wafer 10's processing. Furthermore, the clamp ring 5 is a component that, unlike the processing container 2 and the gas shower head 4, is difficult to prevent the formation of Ru film by providing heating sections (processing container heating section 71, gas shower head heating section 72). For these reasons, it is important to perform a cleaning process (C) to remove the Ru film and standardize the surface condition of the clamp ring 5 for each process. This is because the Ru film is a reflective film, and if a Ru film is formed on the clamp ring 5, the way heat is transferred by radiation changes, which may reduce the in-plane temperature uniformity of the wafer 10.

[0070] Furthermore, as the thickness of the Ru film deposited on the clamping ring 5 increases, the film thickness at the peripheral edge of the wafer 10 tends to decrease. As previously described, in the film deposition process (B), in the process of repeatedly depositing and etching the Ru layer, the CO gas supplied along with the raw material gas during Ru layer deposition is consumed in the reduction of the Ru film on the clamping ring 5. For this reason, in the Ru layer deposition process (B-1), the film thickness of the Ru film decreases at the peripheral edge of the wafer 10 near the clamping ring 5, and as a result, the in-plane uniformity of the film thickness decreases.

[0071] Furthermore, by performing a cleaning step (C) after each process, the increase in the thickness of the Ru film on the clamping ring 5 is suppressed, thereby suppressing the generation of particles caused by the deposition of the Ru film. In this way, by removing the Ru film formed on the clamping ring 5 in the cleaning step (C), the generation of particles is suppressed, the Ru film deposition process can be performed stably, and the uniformity of the deposition process can be improved.

[0072] As described above, the clamping ring 5 is positioned near the wafer 10, and the processing environment for the film deposition process changes depending on whether or not a Ru film 8 is formed on the clamping ring 5. For this reason, in order to improve the uniformity of the film deposition process, it is preferable to perform the cleaning process (C) each time the film deposition process (B) is performed on one wafer 10. However, in some cases, such as when suppressing the generation of particles or prioritizing the throughput of the process, the disclosure also includes cases in which the cleaning process (C) is performed after the film deposition process (B) has been performed on several wafers 10, for example, 2 to 5 wafers 10.

[0073] <Other Examples of Annular Members> Next, other examples of annular members will be described. The annular member may be a shield ring 9, as shown in Figure 7. The shield ring 9 is a member that is placed along the periphery of the mounting table 3A to prevent film deposition on the mounting table 3A and to suppress large positional displacement of the wafer 10, for example, when the mounting table 3A is equipped with an electrostatic chuck. The shield ring 9 will be described with reference to Figure 7. In this configuration, the wafer 10 to be deposited is configured to have a larger diameter than the mounting table 3A, and when the wafer 10 is placed on the mounting table 3A, the periphery of the wafer 10 protrudes outward from the periphery of the mounting table 3A. Here, an example in which the wafer 10 has a larger diameter than the mounting table 3A has been described, but the shield ring 9 can also be placed in a configuration in which the mounting table 3A has a larger diameter than the wafer 10.

[0074] The shield ring 9 includes a substantially horizontal, plate-shaped annular body 91 formed outside the wafer 10 placed on the mounting table 3A, extending from near the side surface of the wafer 10 toward the side wall of a processing container (not shown). An L-shaped region 92 is formed on the inner edge of this annular body 91 to cover the side surface and lower surface of the peripheral edge of the wafer 10, as well as the side surface of the mounting table 3A.

[0075] For example, the shield ring 9 is fixed to the side wall of the processing container via a support member (not shown) at the periphery of the annular body 91. If the processing position of the mounting table 3A is the position shown by the solid line in Figure 7, the transfer position where the wafer 10 is transferred between the mounting table 3A and the vacuum transfer mechanism 19 is set above the processing position, as shown by the dashed line in Figure 7. Thus, when the mounting table 3A, which has received the wafer 10 from the vacuum transfer mechanism 19 at the transfer position, descends to the processing position, the shield ring 9 is positioned on the periphery of the mounting table 3A. The film formation process (B) and the cleaning process (C) are performed with the shield ring 9 positioned on the periphery of the mounting table 3A in the same manner as in the embodiment described above.

[0076] However, if the mounting stage 3A is equipped with an electrostatic chuck, the cleaning process (C) is preferably performed by placing a dummy wafer for stage protection on the mounting stage 3A. In this case, the wafer 10 is brought into the processing container 2 and placed on the mounting stage 3A, and after the Ru film is deposited, the wafer 10 is removed from the processing container 2. Next, the dummy wafer is brought into the processing container 2 and placed on the mounting stage 3A, and the shield ring 9 is placed on the periphery of the mounting stage 3A and cleaning is performed. After the dummy wafer is removed from the processing container 2, the wafer 10 to be deposited is brought in and the Ru film deposition process is performed again.

[0077] Up to this point, we have described a configuration in which the annular members (clamp ring 5 and shield ring 9) are supported in a position relative to the processing container 2, and the annular members are positioned on the periphery of the mounting tables 3 and 3A by raising and lowering the mounting tables 3 and 3A. However, the configuration is not limited to this, and a moving mechanism may be provided on the annular members to allow them to move up and down or horizontally. The annular members may then be raised and lowered or moved horizontally to be positioned on the periphery of the mounting tables 3 and 3A at the processing position to perform the film formation process (B) or the cleaning process (C). In this case, the cleaning process (C) does not necessarily require the mounting tables 3 and 3A and the annular members to be positioned at the processing position. However, if the cleaning gas is supplied from the gas shower head 4, it is preferable to position them at the processing position as they are closer to the gas shower head 4 and the cleaning gas can reach them more easily.

[0078] In the above, the present disclosure is not necessarily limited to the case in which a Ru film is deposited on a single wafer 10 in the processing container 2. For example, a configuration in which multiple mounting stages are arranged horizontally in a common processing container may be adopted. In the example described above, the case in which the "placement process (A) → film deposition process (B) → cleaning process (C)" is performed in this order in each cycle was explained. In contrast, for example, the cleaning process (C) may be performed first in each cycle, such as "cleaning process (C) → placement process (A) → film deposition process (B)". In this case as well, since the Ru film formed on the annular member can be removed by cleaning before the ruthenium film can be deposited on the wafer 10, the uniformity of the process can be improved and the generation of particles can be suppressed.

[0079] The ozone gas supply unit 62 in the film deposition module 12 includes, but is not limited to, a silent discharge type ozonizer 621 that generates plasma as described above. ３If a cleaning gas or etching gas of the appropriate concentration can be supplied, an ozone generator using a chemical method, electric field method, ultraviolet method, etc., may be used instead of the ozonizer 621. Furthermore, although this disclosure shows an example in which one ozonizer 621 is provided for the film deposition module 12, two or more may be provided. If two ozonizers 621 are provided, one ozonizer 621 may be used to supply the cleaning gas and the other ozonizer 621 may be used to supply the etching gas.

[0080] In the cleaning process (C), the thickness of the Ru film formed on the annular member differs depending on the type of film formation process, so it is not always necessary to supply reducing gas together with the cleaning gas. Also, when supplying cleaning gas and reducing gas alternately, the process may start with the supply of cleaning gas or with the supply of reducing gas. Furthermore, in the etching process (B-2), reducing gas may be supplied from the reducing gas supply unit 63 to assist in the etching of a portion of the Ru layer by the etching gas.

[0081] In the example described above, heating by the processing container heating unit 71 and the gas shower head heating unit 72 prevented the formation of a Ru film on the surfaces of the components constituting the processing container 2 and the gas shower head 4. However, depending on the Ru film formation temperature, if the temperature of the processing container 2 and the gas shower head 4 is lower than the film formation temperature, the formation of a Ru film on these components may be suppressed. Therefore, it is not always necessary to provide the processing container heating unit 71 and the gas shower head heating unit 72 in the processing container 2.

[0082] Furthermore, O is not necessarily used as a cleaning gas. ３ It is not necessary to use a gas containing ClF ３The cleaning process (C) may be carried out using a cleaning gas containing halogens, such as gas. Furthermore, the present disclosure may be carried out in combination with a pre-coating process in which the inside of the processing container 2 is coated with a Ru film. Pre-coating involves forming a Ru film on the surface of the mounting table and annular member in advance to equalize the environment inside the processing container. During cleaning, the Ru film deposited on the mounting table and annular member by the film formation process is removed together with the pre-coated Ru film. Then, the surface of the mounting table and annular member is coated with a Ru film again before the film formation process is carried out.

[0083] In the substrate processing system 1 of this disclosure, the number and arrangement of processing modules 11 to 13 and vacuum transport modules 16 and 18 are not limited to the example shown in Figure 1, and the number and arrangement of each device can be set to improve the overall throughput. Furthermore, it is not always necessary to provide the pre-cleaning module 11 and the annealing module 13, and processing modules that perform processing other than pre-cleaning and annealing may be provided. Moreover, it is not a mandatory requirement to provide the first and second vacuum transport modules 191 and 192 and the connection module 17. For example, the second vacuum transport module 18 and the connection module 17 may not be provided, and the processing modules 11 to 13 may be arranged around the first vacuum transport module 16.

[0084] Furthermore, in addition to the processes described above, the substrate processing system 1 also processes gaseous components contained in the wafer (for example, H2 in the air adsorbed on the surface of the incoming wafer 10) before the cleaning process. ２ The system may be configured to perform a degassing process that releases O). In this case, for example, a new degassing module configured to heat the wafer 10 in a vacuum atmosphere may be provided, or the degassing process may be performed in the annealing module 13 or the load lock module 15.

[0085] <Experimental Example 1> Using the film forming module 12 shown in FIG. 2, after forming a 20-nm Ru film on the wafer 10, the wafer 10 was carried out, and a cleaning process (C) was performed to measure the etching amount of the Ru film formed on the clamp ring 5. The Ru film was formed by using DCR gas as the source gas, CO gas as the carrier gas, and Ar gas as the inert gas, and repeating the Ru layer forming process (B-1) and the etching process (B-2) in the same manner as in the above-described embodiment. The film forming conditions are as follows. Processing vessel internal pressure in the Ru layer forming process (B-1): 2.21 Pa (16.6 mTorr) Mounting table temperature: 156.5 ° C DCR gas flow rate: 1.6 sccm CO gas flow rate: 200 sccm Processing vessel internal pressure in the etching process (B-2): 13.3 Pa (100 mTorrT) Concentration of etching gas O ３ Concentration: 150 g / cm ３ Etching gas flow rate: 1000 sccm

[0086] In addition, in the cleaning process (C), as the cleaning gas, ozone-containing oxygen gas with a concentration of 300 g / cm was used, and H gas was used as the reducing gas. The processing vessel internal pressure was 13.3 Pa (100 mTorr), and the mounting table temperature was 156.5 ° C. The flow rates of the O gas and the H gas supplied simultaneously with the cleaning gas are as follows. Example 1: O gas 900 sccm, H gas 100 sccm Example 2: O gas 800 sccm, H gas 200 sccm Example 3: O gas 700 sccm, H gas 300 sccm Example 4: O gas 600 sccm, H gas 400 sccm Example 5: O gas 1000 sccm, H gas 0 sccm​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​This is an example of simultaneously supplying gas. Example 5 is an example of alternately supplying cleaning gas and H ２ gas, and when only H ２ gas is supplied, the flow rate of H ２ gas was set to 1000 sccm. This result is shown in FIG. 8. In the figure, the horizontal axis is the etching time (s), and the vertical axis is the average etching amount (nm). The average etching amount is obtained by measuring the etching amount at a plurality of locations on the Ru film deposited on the clamping ring 5 and finding the average value. Also, in FIG. 8, the data of Example 1 is plotted as a circle (○), Example 2 as a square (□), Example 3 as a diamond (◇), Example 4 as a triangle (△), and Example 5 as an inverted triangle (▽).

[0088] Also, in FIG. 9, for Examples 1 to 5, the relationship between the flow rate of H ２ gas and the average etching amount is shown as a graph. In the figure, the horizontal axis is the flow rate of H ２ gas (sccm), and the vertical axis is the etching rate (nm / min). Similar to FIG. 8, the data of Example 1 is plotted as ○, Example 2 as □, Example 3 as ◇, Example 4 as △, and Example 5 as ▽.

[0089] From FIGS. 8 and 9, it was found that the average etching amount of Examples 1 to 4, which simultaneously supply cleaning gas and reducing gas (H ２ gas), is larger than that of Example 5, which alternately supplies these gases. Also, from the results of Examples 1 to ２ [[ID= 20]]4 in FIG. 9, it was recognized that the higher the flow rate of H ２ gas, the lower the etching rate, and the etching rate is not proportional to the flow rate of H ２ gas. Regarding this reason, it is推测 that when the supply amount of H

[0090] gas is too large, oxygen radicals in the cleaning gas are consumed in the reaction with H, and the active species of oxygen decrease.<Experimental Example 2> In the cleaning process (C) of this disclosure, the relationship between temperature and etching amount was confirmed. Similar to Experimental Example 1, a 20 nm Ru film was deposited on the wafer 10 using the film deposition module 12 shown in Figure 2. After that, the wafer 10 was removed, and the cleaning process (C) was performed to measure the etching amount of the Ru film formed on the clamp ring 5. The film deposition conditions for the Ru film were the same as in Experimental Example 1.

[0091] Furthermore, in the cleaning process (C), O is used as the cleaning gas. ３ The concentration is 300 g / cm³. ３ Using ozone-containing oxygen gas, the pressure inside the processing container was set to 13.3 Pa (100 mTorr), and the temperature of the mounting platform 3 was varied. H was used as the reducing gas. ２ Using gas and CO gas, the temperature of the mounting platform 3 was set to 80°C, 146.5°C, and 156.5°C. The cleaning gas was supplied simultaneously with the CO gas. ２ The gas flow rate is 1000 sccm, H ２ The gas flow rate was set to 1000 sccm, and the CO gas flow rate was also set to 1000 sccm.

[0092] The results are shown in Figure 10. In the figure, the horizontal axis represents the etching temperature (°C), and the vertical axis represents the etching amount (nm), where H is the reducing gas. ２ The case where it is a gas is shown by a shaded bar graph, and the case where it is CO gas is shown by a white bar graph. From Figure 10, the reducing gas is H ２ In both the case of gas and CO gas, the amount of etching is greatest when the temperature of the mounting stage 3 is 80°C, especially H ２ With gas, it was found that the amount of etching increases with lower temperatures, and at 80°C, the etching amount is about twice as high as at 146.5°C and 156.5°C. ２ In gases, the reason why etching increases as the temperature decreases is that at low temperatures, the oxidation reaction that oxidizes the surface of the Ru film does not proceed easily. Therefore, this oxidation reaction and the Ru film ３ RuO ４ It is presumed that this balances with the etching reaction that removes material, thereby suppressing a decrease in the etching rate.

[0093] On the other hand, CO gas is H２ It was confirmed that the change in etching amount with respect to temperature changes is not as large as with gases. Therefore, it is thought that the temperature of the cleaning process (C) can be appropriately selected depending on the type of reducing gas. H ２ When using gas, a lower temperature results in a greater amount of etching, so if cleaning is the priority, it is preferable to use a low temperature of around 80°C. However, since the film deposition temperature is 100°C to 250°C, if throughput is the priority, the cleaning process (C) may be performed at a temperature close to the film deposition temperature.

[0094] It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The above embodiments may be omitted, substituted, modified, and combined in various ways without departing from the scope and spirit of the appended claims.

[0095] 10 Semiconductor wafer 12 Film deposition apparatus (substrate processing apparatus) 2 Processing container 3 Mounting table 5 Clamping ring (annular member)

Claims

1. A method for forming a ruthenium film on a substrate, comprising: a substrate processing apparatus disposed in a processing container and on which a substrate to be formed is placed; and an annular member disposed along the periphery of the aforementioned platform during the period in which the film is formed, the method comprising: (A) a step of placing the substrate to be formed on the aforementioned platform and the annular member disposed along the periphery of the platform; (B) a step of supplying a ruthenium raw material gas into the processing container and forming a ruthenium film on the substrate; and (C) a step of supplying a cleaning gas into the processing container with the annular member disposed along the periphery of the aforementioned platform after the substrate on which the ruthenium film has been formed has been removed from the processing container and the ruthenium film formed on the annular member has been removed, wherein a cycle in which steps (A) to (C) are performed in this order is repeated.

2. The method according to claim 1, wherein the annular member is a clamping ring that covers the peripheral edge of the upper surface of the substrate placed on the mounting base when it is positioned on the peripheral edge of the mounting base described above.

3. The method according to claim 1, wherein the substrate to be film-deposited is configured to have a larger diameter than the stand described above, and when the substrate is placed on the stand described above, the peripheral edge of the substrate protrudes outward from the peripheral edge of the stand described above, and the annular member is a shield ring having an L-shaped region in its longitudinal cross-section to cover the side surface of the substrate, the lower surface of the peripheral edge, and the side surface of the stand described above.

4. The method according to claim 1, wherein the (B) step includes (B-1) supplying a ruthenium raw material gas into the processing vessel to form a ruthenium layer for forming the ruthenium film, and (B-2) supplying an etching gas containing ozone gas into the processing vessel to etch a part of the ruthenium layer, and the cycle in which steps (B-1) to (B-2) are performed in this order is repeated.

5. The method according to claim 4, wherein in step (C), a gas containing ozone is used as the cleaning gas, and at least one supply adjustment selected from the following is performed: adjusting the pressure inside the processing container to be higher than in step (B-2), adjusting the supply flow rate of the cleaning gas to be greater than the supply flow rate of the etching gas, or adjusting the ozone concentration in the cleaning gas to be higher than the ozone concentration in the etching gas, so that the amount of ozone supplied to the processing container is greater than in step (B-2).

6. The method according to claim 5, wherein the mounting base is provided with a heating section for heating the substrate, and when the annular member is heated by heat transfer from the mounting base, in step (C), temperature adjustment is performed to lower the heating temperature of the mounting base by the heating section compared to step (B-2).

7. The method according to claim 1, wherein in step (C), a gas containing ozone is used as the cleaning gas, and further in step (C), a reducing gas is supplied to assist in the removal of the ruthenium film by the cleaning gas containing ozone.

8. The method according to claim 7, wherein the reducing gas is selected from the group of reducing gases consisting of hydrogen gas or its plasma, carbon monoxide gas, ammonia gas or its plasma, monomethylhydrazine gas, and hydrazine gas.

9. An apparatus for depositing a ruthenium film on a substrate, comprising: a processing container; a mounting table disposed within the processing container on which the substrate to be deposited is placed; an annular member disposed along the periphery of the mounting table during the period in which the film is deposited; a raw material gas supply unit for supplying a ruthenium raw material gas to the processing container; a cleaning gas supply unit for supplying a cleaning gas to remove the ruthenium film to the processing container; and a control unit. The control unit is configured to output a control signal for repeatedly performing a cycle in the order of (A) to (C), which includes the steps of: (A) placing the substrate to be film-formed on the aforementioned stand and positioning the annular member on the periphery of the stand; (B) supplying the raw material gas into the processing container to form a ruthenium film on the substrate; and (C) supplying the cleaning gas into the processing container to remove the ruthenium film formed on the annular member, with the annular member positioned on the periphery of the aforementioned stand after the substrate on which the ruthenium film has been formed has been transported out of the processing container.

10. The apparatus according to claim 9, wherein the annular member, when positioned on the periphery of the mounting base described above, is a clamping ring that covers the periphery of the upper surface of the substrate placed on the mounting base.

11. The apparatus according to claim 9, wherein the substrate to be film-formed is configured to have a larger diameter than the stand described above, and when the substrate is placed on the stand described above, the peripheral edge of the substrate protrudes outward from the peripheral edge of the stand described above, and the annular member is a shielding ring having an L-shaped region in its longitudinal cross-section to cover the side surface of the substrate, the lower surface of the peripheral edge, and the side surface of the stand described above.

12. The apparatus according to claim 9, wherein the control unit is configured to output a control signal for repeating a cycle in which, in step (B), the steps of (B-1) supplying a ruthenium raw material gas into the processing container to form a ruthenium layer for forming the ruthenium film, and (B-2) supplying an etching gas containing ozone gas into the processing container to etch a part of the ruthenium layer, are performed in the order of (B-1) to (B-2).

13. The apparatus according to claim 12, wherein the cleaning gas supply unit is configured to supply a gas containing ozone as the cleaning gas, and the control unit is configured to output a control signal that performs at least one supply amount adjustment selected from the following: adjusting the pressure inside the processing container to be higher, adjusting the supply flow rate of the cleaning gas to be higher than the supply flow rate of the etching gas, or adjusting the ozone concentration in the cleaning gas to be higher than the ozone concentration in the etching gas, so that the amount of ozone supplied to the processing container is greater when step (C) is performed than when step (B-2) is performed.

14. The apparatus according to claim 13, wherein the mounting base is equipped with a heating unit for heating the substrate, and when the annular member is heated by heat transfer from the mounting base, the control unit is configured to output a control signal in step (C) that lowers the heating temperature of the mounting base by the heating unit compared to step (B-2).

15. The apparatus according to claim 9, wherein the cleaning gas supply unit is configured to supply a gas containing ozone as the cleaning gas, and further comprises a reducing gas supply unit for supplying a reducing gas to the processing container, and the control unit is configured to output a control signal in step (C) for supplying the reducing gas in order to assist in the removal of the ruthenium film by the cleaning gas containing ozone.

16. The apparatus according to claim 15, wherein the reducing gas supply unit is configured to supply a reducing gas selected from a group of reducing gases consisting of hydrogen gas or its plasma, carbon monoxide gas, ammonia gas or its plasma, monomethylhydrazine gas, and hydrazine gas.

17. The apparatus according to claim 9, wherein the processing container is equipped with a gas shower head for introducing the raw material gas supplied from the raw material gas supply unit into the processing container, and the processing container and the gas shower head are provided with a processing container heating unit and a gas shower head heating unit for heating the constituent members to prevent the formation of the ruthenium film on the surfaces of the constituent members constituting the processing container and the gas shower head.

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