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

Abstract

When placing a substrate on a mounting table and depositing a Ru film, the Ru film formed on the annular member positioned at the periphery of the mounting table is removed. [Solution] A substrate processing apparatus comprising a mounting table placed inside a processing container on which a substrate to be coated is placed, and an annular member placed along the periphery of the mounting table, the apparatus includes the steps of (A) placing the substrate to be coated on the mounting table and the annular member being placed on the periphery of the mounting table, (B) supplying ruthenium raw material gas into the processing container and depositing a Ru film on the substrate, and (C) supplying cleaning gas into the processing container with the annular member being placed on the periphery of the mounting table after the substrate with the Ru film deposited has been removed from the processing container, to remove the Ru film formed on the annular member, and repeating a cycle in which steps (A) to (C) are performed in this order.

Description

[Technical Field]

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

[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 an insulating film formed on a 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 being carried out 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, thereby removing the ruthenium film attached to the inner wall of the reaction vessel. The film deposition apparatus described in Patent Document 1 is a vertical heat treatment apparatus that places a large number of workpieces on a wafer boat in multiple stages and transports them into a reaction vessel. Patent Document 1 does not describe a single-wafer film deposition apparatus that performs film deposition by placing workpieces on a mounting table. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2003-13232 [Overview of the project] [Problems that the invention aims to solve]

[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. [Means for solving the problem]

[0006] This disclosure is, A method for depositing a ruthenium film on a substrate, A substrate processing apparatus comprising a mounting platform placed inside a processing container on which a substrate to be coated is placed, and an annular member positioned along the periphery of the mounting platform during the period in which the coating is performed, (A) A step of placing the substrate to be film-deposited on the aforementioned stand and the annular member on the peripheral edge of the stand, (B) A step of supplying ruthenium raw material gas into the processing container and forming a ruthenium film on the substrate, (C) After the substrate on which the ruthenium film has been formed has been removed from the processing container, the annular member is positioned on the periphery of the aforementioned stand, and a cleaning gas is supplied into the processing container to remove the ruthenium film formed on the annular member, This method involves repeating a cycle in which steps (A) to (C) described above are executed in this order. [Effects of the Invention]

[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. [Brief explanation of the drawing]

[0008] [Figure 1] This is a plan view showing one embodiment of a substrate processing system. [Figure 2] This is a longitudinal cross-sectional side view showing one embodiment of a film deposition apparatus. [Figure 3] These are a plan view and a side view showing a part of the film deposition apparatus. [Figure 4] This is an explanatory diagram showing a state in which a ruthenium film has been formed on an annular member (clamp ring). [Figure 5] This is a flowchart showing one embodiment of the film deposition method. [Figure 6]It is an explanatory diagram showing the state of the annular member (clamping ring) during the implementation period of the film forming method. [Figure 7] It is a longitudinal sectional side view showing a part of another embodiment of the film forming apparatus. [Figure 8] It is a first characteristic diagram showing experimental results. [Figure 9] It is a second characteristic diagram showing experimental results. [Figure 10] It is a third characteristic diagram showing experimental results.

Embodiments for Carrying Out the Invention

[0009] <Substrate Processing System> FIG. 1 is a schematic plan view illustrating a substrate processing system including a substrate processing process (hereinafter referred to as a "film forming apparatus") for forming a ruthenium film according to the present disclosure. The substrate processing system 1 is a multi-chamber system including a plurality of processing modules 11, 12, and 13 including a processing module for forming a ruthenium film (Ru film) on a semiconductor wafer 10 as a substrate (hereinafter referred to as "wafer 10"). In this example, in the substrate processing system 1, a case where a process of forming a Ru film so as to fill a recess formed in the surface layer of the wafer 10 will be described as an example. For example, on the wafer 10, a tungsten layer (W layer) and an insulating layer such as a silicon oxide film (SiO2) are laminated, and a plurality of recesses are formed in this insulating layer by etching.

[0010] In the substrate processing system 1, in this example, the processing module 11 is configured as a pre-clean module, the processing module 12 is configured as a film forming module, and the processing module 13 is configured as an annealing module, respectively. Hereinafter, these processing modules 11 to 13 will also be referred to as "pre-clean module 11, film forming module 12, annealing module 13". The 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. The pre-clean module 11 is a module that performs a pre-cleaning treatment to remove the metal oxide film formed on the bottom wall of the recess before the Ru film deposition treatment. The annealing module 13 is a module that performs an annealing treatment on the Ru film after the Ru film deposition treatment.

[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 the wafer 10 between the loader module 14 and the first vacuum transfer module 16, and its interior is configured to be adjustable to atmospheric pressure and the pressure inside the first vacuum transfer 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 the wafer 10 between the first and second vacuum transfer modules 16 and 18, and is adjusted to the same vacuum atmosphere pressure as inside the first and second vacuum transfer modules 16 and 18.

[0014] When viewed from the front of the first vacuum transport module 16, cleaning modules 11 and film deposition modules 12 are provided on both the left and right sides, arranged in a front-to-back configuration. The first vacuum transport mechanism 191 is configured to transport the wafer 10 between these processing modules 11 and 12, the connection module 17, and the load lock module 15. Furthermore, on both the left and right sides of the second vacuum transport module 18, when viewed from the front, are a film deposition module 12 and an annealing module 13, respectively, arranged in a front-to-back configuration. The second vacuum transport mechanism 192 is configured to transport the wafer 10 between these processing modules 12 and 13 and the 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 transportation 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 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 opposite 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 a heater 31 is embedded inside it, which 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 stage 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 stage 3, preventing reaction products and by-products such as Ru from accumulating on the surface of the mounting stage 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 stage 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 passes through 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 lifting plate 35 and the bottom wall of the lower container 22 are airtightly joined by a bellows 36. Thus, 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 positioned 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 that 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, ceramics such as alumina (Al2O3) or 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 and 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 few 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 61-63 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, Ru3(CO) is used as the raw material gas for the Ru film. 12 (DCR: Dodecacarbonyltrilthenium) gas is used, 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 comprises an oxygen (O2) gas supply source 621, a valve V21, a flow rate adjustment unit 622, an ozonizer 623, and a valve V22, which are arranged in this order downstream in the branched gas supply pipe 64. The O2 gas supplied from the oxygen gas supply source 621 is supplied to the ozonizer 623 after its flow rate is controlled by the flow rate adjustment unit 622. The ozonizer 623 is configured, for example, as a silent discharge type discharge tube, and is configured to generate a discharge by electrical energy applied from an external power source (not shown), activating at least a portion of the supplied O2 gas to supply ozone (O3) gas. The ozonizer 623 then adjusts the O3 concentration to, for example, 0 g / m³ by adjusting the voltage applied from the external power source. 3 From 400g / m 3 It can be adjusted down to (based on 0°C and 101.3kPa; the same applies to O3 concentration below). In this way, the ozonizer 623 is configured to supply ozone-containing oxygen gas with different O3 concentrations. Furthermore, by adjusting both the supply flow rate of O2 gas from the oxygen gas supply source 621 and the applied voltage, it is possible to change the supply flow rate of O3 gas while maintaining the desired O3 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. Furthermore, the cleaning gas used in the process of removing the Ru film formed on the annular clamp ring 5 is also an ozone-containing gas. However, the etching gas and the cleaning gas differ in their O3 concentration, with the cleaning gas having a higher O3 concentration than the etching gas.

[0033] In this disclosure, the ozonizer 623 has an etching gas with an O3 concentration of 100 g / m². 3 More than 400g / m 3 For example, an O3 concentration of less than 150 g / m³ 3 It supplies ozone-containing oxygen gas. Additionally, the cleaning gas has an O3 concentration of 100 g / m³. 3 More than 400g / m 3Within the following range, an ozone-containing oxygen gas having an ozone concentration higher than that of the ozone-containing oxygen gas supplied as an etching gas, for example, an ozone concentration of 300 g / m 3 of ozone-containing oxygen gas is supplied. From the above, the ozone gas supply unit 62 corresponds to the cleaning gas supply unit. The flow rate of the O2 gas supplied from the oxygen gas supply source 621 to the ozonizer 623 is, for both the supply of the etching gas and the cleaning gas, for example, 400 sccm to 20,000 sccm.

[0034] The reducing gas supply unit 63 includes a supply source 631 of a reducing gas, for example, CO gas, a flow rate adjustment unit 632, and a valve V3. As will be described later, in the ruthenium film formation process, for the purpose of adjusting the decomposition of Ru3(CO) 12 CO gas is supplied in parallel with the source gas separately from the carrier gas. The reducing gas supply unit 63 supplies the above-mentioned CO gas supplied in parallel with the source gas in the film formation process, and supplies CO gas together with the cleaning gas in the cleaning process. Further, 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 of each process gas. In this case, the supplied inert gas purges each process gas to suppress the reaction of each process gas with each other and the deposition of products.

[0035] Furthermore, in this example, a processing container heating unit 71 and a gas shower head heating unit 72 are provided in the processing container 2 and the gas shower head 4, respectively. These processing container heating unit 71 and gas shower head heating unit 72 are configured to heat these constituent members in order to prevent the formation of a Ru film on the surfaces of the constituent members constituting the processing container 2 and the gas shower head 4. For example, the processing container heating unit 71 is constituted by heaters provided on the side wall and bottom wall of the processing container 2, and for example, the gas shower head heating unit 72 is constituted by 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 configured to supply plasma from the supplied H2 gas between the gas shower head and the mounting stage and to supply it to the wafer 10 to remove the metal oxide film formed in the recesses. The bottom surface of the recesses described above has an exposed 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 is configured to heat the wafer 10 placed on the mounting stage while supplying an inert gas, such as N2 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 back to the transport container C in the following order: second vacuum transport module 18 → connection module 17 → first vacuum transport module 16 → load lock module 15 → loader module 14.

[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 will be described later. Then, with the clamp ring 5 placed 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, conventionally, in order to standardize the environment inside the processing container 2 during film deposition and to ensure stable film deposition, a Ru film coating was sometimes applied to the processing container 2. However, as the Ru film deposition process is repeated in the processing container 2, 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 may not be maintained due to changes in the state of the Ru film formed on the clamp ring 5.

[0041] One of the factors that is thought to contribute to particle generation is the increasing thickness of the Ru film deposited on the clamp ring 5. As the film thickness increases, it becomes more prone to delamination, and it is presumed that this delamination generates particles. Another possible factor 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. As will be described later, the film deposition process involves repeatedly depositing a Ru layer and etching a portion of the Ru layer, during which 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, delamination is likely to occur at their interface, and it is presumed that this delamination generates 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 supply amount of raw material gas 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, this disclosure includes a step to remove the Ru film formed on the clamp ring 5 using a cleaning gas after the step of depositing the Ru film on the wafer 10. 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 described herein is carried out by repeating a cycle in the deposition module 12 in the order of placement (A), deposition (B), and cleaning (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 film deposition process (B) is performed in which a Ru raw material gas is supplied into the processing container 2 to deposit a Ru film on the wafer 10 (step S2). This film deposition process (B) is performed by repeating multiple cycles 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 at which Ru film deposition is suppressed, for example, the lower limit of the 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, to the processing space S1 together with the carrier gas CO gas, and the reducing gas supply unit 63 supplies CO gas for reaction adjustment. In addition, 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 deposited 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(Ru3(CO) 12 DCR gas is decomposed into Ru via Ru(CO)4 and Ru(CO)5, but Ru(CO)5 is more stable than Ru(CO)4 and is less susceptible to thermal decomposition. The presence of CO gas makes DCR gas more readily convert to Ru(CO)5, and in this way, CO gas plays a role in suppressing the decomposition of Ru raw material gas in the gas supply pipe 64, gas shower head 4, and processing space S1, thereby 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: processing vessel pressure: 2.21 Pa (16.6 mTorr), mounting stage temperature: 155°C or 180°C, DCR gas flow rate: 1.6~2.0 sccm, CO gas flow rate: 200~300 sccm. In the Ru layer deposition process (B-1), depending on the desired Ru film thickness, 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 repeating the deposition process (B-1) multiple times in this way, as described above, for example, the supply of DCR gas is stopped and the supply of CO gas is continued to perform a DCR purge for 5 seconds. Next, the supply of CO gas is stopped, while the exhaust from the processing container 2 continues. After this exhaust continues 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 becoming blocked and voids from forming as the thickness increases due to further deposition of Ru on the sides of the recess.

[0051] Specifically, the supply of DCR gas and CO gas is stopped, and as etching gas, for example, an O3 gas with a concentration of 150 g / m³ is supplied from the ozone gas supply unit 62. 3 Ozone-containing oxygen gas is supplied. As a result, the surface portion of the Ru layer at the bottom of the recess and the Ru on the sides react with the O3 gas to form volatile ruthenium tetroxide (RuO4), which is then exhausted and removed by the exhaust mechanism 23. An example of the processing conditions for the etching process (B-2) is as follows: processing vessel pressure: 2.21 Pa (16.6 mTorr), mounting stage temperature: 155°C or 180°C, etching gas flow rate: 1000 sccm, and the execution time of the etching process (B-2) (etching gas supply time): 25 sec. However, as will be described later, the processing vessel pressure and 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 film deposition process (B), the mounting platform 3 is lowered to the transport position. Then, the gate valve GV is opened to transfer the wafer 10 from the mounting platform 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 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 unit 71 and the gas shower head heating unit 72, which suppresses the deposition of Ru film on the components of the processing container 2 and the gas shower head 4.

[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 clamp 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 has been formed on the surface of the clamp 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) is set to supply a larger amount of O3 to the processing container 2 than the etching gas described above. While the etching process (B-2) etches a portion of the Ru layer, this cleaning process (C) removes the Ru film 8 deposited on the clamp ring 5. 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 O3 concentration in the cleaning gas is adjusted to be higher than the O3 concentration in the etching gas. At least one of these adjustments to increase the amount of O3 supplied to the processing container 2 is selected and implemented.

[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, experimental examples have shown 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 stage 3 should be adjusted according to the type of reducing gas and the processing method, 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, as an example of the processing conditions for the cleaning process (C), the cleaning gas has an O3 concentration of, for example, 100-400 g / m³. 3Ozone-containing oxygen gas is used. The processing container pressure is set to 13.3~933 Pa (0.1~7 Torr), the mounting platform temperature to 60~250°C, and the cleaning gas flow rate (O2 gas flow rate) to 400~20000 sccm. In this cleaning process (C), the Ru film 8 formed on the surface of the clamp ring 5 reacts with O3 gas to become RuO4, vaporizes, and is then removed by exhaust from the exhaust mechanism 23 (see Figure 6(c)).

[0060] As the cleaning process (C) continues in this manner, ruthenium oxide (RuO2: ruthenium dioxide) may be formed on the surface of the Ru film 8 through a reaction with O3 gas or O2 gas. This RuO2 is also removed by O3 gas by being converted to RuO4, but 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 reducing gas, CO gas, is repeated.

[0061] Specifically, after supplying cleaning gas from the ozone gas supply unit 61 for a predetermined period, 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, the reducing gas can be selected from a group of reducing gases consisting of hydrogen (H2) gas or its plasma, ammonia (NH3) gas or its plasma, monomethylhydrazine ((CH3)(NH)NH2) gas, and hydrazine (N2H4) gas. Furthermore, multiple gases selected from these may be supplied simultaneously or alternately.

[0063] The supply conditions for CO gas 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 20,000 sccm. When H2 gas is used as the reducing gas, the supply conditions are: pressure inside the processing vessel: 13.3 to 933 Pa (0.1 to 7 Torr), mounting stage temperature: 60 to 250°C, and H2 gas flow rate: 100 to 20,000 sccm. Thus, 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 mounting stage temperature with the conditions for supplying the cleaning gas.

[0064] Thus, in cleaning step (C), the Ru film 8 is removed by repeatedly performing a cycle of alternately supplying cleaning gas and reducing gas. The supply time for cleaning gas is, for example, 25 seconds, and the supply time for reducing gas is, for example, 120 seconds. The conditions and cleaning times for cleaning step (C) described above should be determined in advance through experiments. In this process, the Ru film deposited on the clamp ring 5 is removed during the cleaning process (C), but in the film deposition process (B), the Ru film deposited in locations other than the clamp ring 5 within 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 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. This allows for stable film deposition, improving the uniformity of the film deposition process and suppressing the generation of particles.

[0068] In other words, as shown in Figure 6, at the stage 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 clamping ring 5 is positioned around the wafer 10 and has a significant impact on the processing of the wafer 10. Furthermore, unlike the processing container 2 and the gas shower head 4, it is difficult to prevent the formation of Ru film on the clamping ring 5 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 to ensure that the surface condition of the clamping ring 5 is consistent after each processing. This is because the Ru film is a reflective film, and if a Ru film is formed on the clamping 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 processing step, the increase in the thickness of the Ru film on the clamp ring 5 is suppressed, thereby reducing the generation of particles caused by the deposition of the Ru film. In this way, by removing the Ru film formed on the clamp ring 5 in the cleaning process (C), particle generation can be 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 processing throughput, 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 ring-shaped 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 positioned along the periphery of the mounting table 3A to prevent film formation on the mounting table 3A and to suppress large positional displacement of the wafer 10, for example, when the mounting table 3A is configured to have an electrostatic chuck. The shield ring 9 will be explained with reference to Figure 7. In this configuration, the wafer 10 to be deposited on is configured to have a larger diameter than the mounting stage 3A, and when the wafer 10 is placed on the mounting stage 3A, the peripheral edge of the wafer 10 protrudes outward from the peripheral edge of the mounting stage 3A. Although this example describes a case where the wafer 10 has a larger diameter than the mounting stage 3A, the shield ring 9 can also be placed in a configuration where the mounting stage 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 deposition 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, this 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 this disclosure, the present invention is not necessarily limited to the case in which a Ru film is deposited on a single wafer 10 within the processing container 2. For example, a configuration in which multiple mounting stages are arranged horizontally within a common processing container may be adopted. In the example described above, the case where 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 ozone generator 621 that generates plasma as described above. For example, if cleaning gases and etching gases of various O3 concentrations as described above can be supplied, an ozone generator using a chemical method, electric field method, ultraviolet method, etc., may be used instead of the ozone generator 621. In addition, although this disclosure shows an example in which one ozone generator 621 is provided in the film deposition module 12, two or more may be provided. If two ozone generators 621 are provided, one ozone generator 621 may supply cleaning gas and the other ozone generator 621 may supply 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 deposition process, so it is not always necessary to supply a reducing gas along with the cleaning gas. Furthermore, when supplying cleaning gas and reducing gas alternately, the process may be started with the supply of cleaning gas, or it may be started 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, it is not always necessary to use a gas containing O3 as the cleaning gas; the cleaning process (C) may be carried out using a cleaning gas containing a halogen, such as ClF3 gas. Furthermore, this 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 11-13 and vacuum transport modules 16, 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, 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 11-13 may be arranged around the first vacuum transport module 16.

[0084] Furthermore, in addition to the processes described above, the substrate processing system 1 may be configured to perform a degassing process, for example, to release gaseous components contained in the wafer (e.g., H2O in the air adsorbed on the surface of the incoming wafer 10) before the cleaning process. In this case, a degassing module configured to heat the wafer 10 under a vacuum atmosphere may be newly provided, or the degassing process may be performed in the annealing module 13 or the load lock module 15. [Examples]

[0085] <Experimental Example 1> In the film deposition module 12 shown in Figure 2, a 20 nm Ru film was deposited on the wafer 10. After that, the wafer 10 was removed, and a cleaning process (C) was performed to measure the amount of etching of the Ru film formed on the clamp ring 5. The Ru film was deposited using DCR gas as the source gas, CO gas as the carrier gas, and Ar gas as the inert gas, and the Ru layer deposition process (B-1) and etching process (B-2) were repeated in the same manner as in the embodiment described above. The deposition conditions were as follows. Pressure inside the processing vessel during the Ru layer deposition process (B-1): 2.21 Pa (16.6 mTorr) Mounting table temperature: 156.5℃ DCR gas flow rate: 1.6 sccm CO gas flow rate: 200 sccm Pressure inside the processing vessel during the etching process (B-2): 13.3 Pa (100 mTorrT) Etching gas O3 concentration: 150 g / cm³ 3 Etching gas flow rate: 1000 sccm

[0086] Furthermore, in the cleaning process (C), the cleaning gas used is O3 with a concentration of 300 g / cm³. 3 Ozone-containing oxygen gas was used, and H2 gas was used as the reducing gas. The pressure inside the processing container was 13.3 Pa (100 mTorr), and the temperature of the mounting platform was 156.5°C. The flow rates of the O2 gas and H2 gas supplied simultaneously with the cleaning gas were as follows. Example 1: 900 sccm of O2 gas, 100 sccm of H2 gas Example 2: 800 sccm of O2 gas, 200 sccm of H2 gas Example 3: 700 sccm of O2 gas, 300 sccm of H2 gas Example 4: 600 sccm of O2 gas, 400 sccm of H2 gas Example 5: 1000 sccm of O2 gas, 0 sccm of H2 gas

[0087] Examples 1 to 4 are examples in which cleaning gas and H2 gas are supplied simultaneously. Example 5 is an example in which cleaning gas and H2 gas are supplied alternately, and when only H2 gas is supplied, the flow rate of H2 gas is set to 1000 sccm. The results are shown in Figure 8. In the figure, the horizontal axis represents etching time (s), and the vertical axis represents the average etching amount (nm). The average etching amount was calculated by measuring the etching amount at multiple locations on the Ru film deposited on the clamp ring 5 and averaging the results. In Figure 8, the data for Example 1 is plotted as a circle (○), Example 2 as a square (□), Example 3 as a rhombus (◇), Example 4 as a triangle (△), and Example 5 as an inverted triangle (▽).

[0088] Furthermore, Figure 9 shows a graph illustrating the relationship between the H2 gas flow rate and the average etching amount for Examples 1 to 5. In the graph, the horizontal axis represents the H2 gas flow rate (sccm), and the vertical axis represents the etching rate (nm / min). Similar to Figure 8, the data for Example 1 is plotted with ○, Example 2 with □, Example 3 with ◇, Example 4 with △, and Example 5 with ▽.

[0089] Figures 8 and 9 show that the average etching amount was higher in Examples 1-4, where the cleaning gas and reducing gas (H2 gas) were supplied simultaneously, than in Example 5, where these gases were supplied alternately. Furthermore, the results from Examples 1-4 in Figure 9 showed that the etching rate decreased as the H2 gas flow rate increased, indicating that the etching rate was not proportional to the H2 gas flow rate. This is presumed to be because if the H2 gas supply is too high, oxygen radicals in the cleaning gas are consumed in the reaction with H, reducing the number of oxygen reactive species.

[0090] <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 deposition module 12 shown in Figure 2. After that, the wafer 10 was removed, and the cleaning process (C) was performed to measure the amount of etching of the Ru film formed on the clamp ring 5. The deposition conditions for the Ru film were the same as in Experimental Example 1.

[0091] Furthermore, in the cleaning process (C), the cleaning gas used is O3 with a concentration of 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. H2 gas and CO gas were used as reducing gases, and the temperature of the mounting platform 3 was set to 80°C, 146.5°C, and 156.5°C. The flow rates of the O2 gas, H2 gas, and CO gas supplied simultaneously with the cleaning gas were 1000 sccm, 1000 sccm, and 1000 sccm, respectively.

[0092] The results are shown in Figure 10. In the figure, the horizontal axis represents etching temperature (°C), and the vertical axis represents etching amount (nm). The case where the reducing gas is H2 gas is shown as a shaded bar graph, and the case where the reducing gas is CO gas is shown as a white bar graph. Figure 10 shows that, in both cases where the reducing gas is H2 gas or CO gas, the amount of etching is greatest when the temperature of the mounting stage 3 is 80°C. In particular, with H2 gas, the amount of etching increases as the temperature decreases, and at 80°C, it is about twice as much as at 146.5°C and 156.5°C. The reason why the amount of etching increases as the temperature decreases with H2 gas is that the oxidation reaction that oxidizes the surface of the Ru film does not proceed easily at low temperatures. Therefore, it is presumed that a balance is maintained between this oxidation reaction and the etching reaction in which the Ru film is removed by O3 to become RuO4, thus suppressing a decrease in the etching rate.

[0093] On the other hand, it was confirmed that the amount of etching in response to temperature changes is not as large for CO gas as it is for H2 gas. Therefore, the temperature of the cleaning process (C) can be appropriately selected depending on the type of reducing gas. When using H2 gas as the reducing gas, a lower temperature results in a larger etching amount, so if cleaning is the priority, it is preferable to set the temperature to a low 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. [Explanation of Symbols]

[0095] 10 Semiconductor wafers 12. Film deposition equipment (substrate processing equipment) 2 Processing container 3. Mounting platform 5. Clamping ring (annular member)

Claims

1. A method for depositing a ruthenium film on a substrate, A substrate processing apparatus comprising a mounting platform placed inside a processing container on which a substrate to be coated is placed, and an annular member positioned along the periphery of the mounting platform during the period in which the coating is performed, (A) A step of placing the substrate to be film-formed on the stand described above, and the annular member being positioned on the periphery of the stand, (B) A step of supplying a ruthenium raw material gas into the processing container and forming a ruthenium film on the substrate, (C) After the substrate on which the ruthenium film has been formed has been removed from the processing container, the annular member is positioned on the periphery of the aforementioned stand, and a cleaning gas is supplied into the processing container to remove the ruthenium film formed on the annular member, A method in which the above steps (A) to (C) are performed in this order, and the cycle 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 substrate to be film-deposited is configured to have a larger diameter than the aforementioned stand, and when the substrate is placed on the aforementioned stand, the peripheral edge of the substrate protrudes outward from the peripheral edge of the aforementioned stand. The method according to claim 1, wherein the annular member is a shielding ring having an L-shaped region in its longitudinal cross-section for covering the side surface and the lower surface of the peripheral edge of the substrate, and the side surface of the stand described above.

4. The aforementioned step (B) is, (B-1) A step of supplying a ruthenium raw material gas into the processing container and forming a ruthenium layer for forming the ruthenium film, (B-2) The process includes supplying an etching gas containing ozone gas into the processing container and etching a portion of the ruthenium layer, The method according to claim 1, wherein the process described above (B-1) to (B-2) is repeated in a cycle in this order.

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.

6. 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, The method according to claim 5, wherein in step (C), temperature adjustment is performed to lower the heating temperature of the base described above by the heating unit compared to step (B-2).

7. In step (C) above, a gas containing ozone is used as the cleaning gas. The method according to claim 1, further comprising supplying a reducing gas in step (C) 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 onto a substrate, Processing container and A mounting platform is placed inside the processing container on which the substrate to be film-deposited is placed, During the period in which the aforementioned film formation is performed, an annular member is positioned along the periphery of the aforementioned mounting base, The processing container is provided with a raw material gas supply unit that supplies ruthenium raw material gas, The processing container includes a cleaning gas supply unit that supplies a cleaning gas for removing the ruthenium film, It comprises a control unit and, 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 is a clamping ring that covers the peripheral edge of the upper surface of the substrate placed on the mounting base when positioned on the peripheral edge of the mounting base described above.

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

12. The control unit, The apparatus according to claim 9, wherein in step (B), the apparatus is configured to output a control signal for repeating a cycle in which 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 cleaning gas supply unit is configured to supply a gas containing ozone as the cleaning gas. The apparatus according to claim 12, wherein the control unit is configured to output a control signal that performs at least one supply 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, such 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 mounting base is equipped with a heating section for heating the substrate, and when the annular member is heated by heat transfer from the mounting base described above, The apparatus according to claim 13, wherein the control unit is configured to output a control signal in step (C) to perform temperature adjustment to lower the heating temperature of the base described above by the heating unit than in step (B-2).

15. The cleaning gas supply unit is configured to supply a gas containing ozone as the cleaning gas. Furthermore, the processing container is equipped with a reduction gas supply unit for supplying reduction gas. The apparatus according to claim 9, wherein the control unit is configured to output a control signal in step (C) for supplying the reducing gas 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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