Method for recovering platinum group metals, method for manufacturing platinum group metal-containing film, and film forming apparatus

Abstract

A method according to the present invention is for recovering a platinum group metal present within a film formation chamber after introducing a feedstock gas containing the platinum group metal into the film formation chamber and forming a film containing the platinum group metal on the surface of a substrate housed within the film formation chamber. The method is provided with: (i) a step for introducing a fluorine-containing cleaning gas into the film formation chamber after the substrate has been removed therefrom; and (ii) a step for introducing the cleaning gas discharged from the film formation chamber into a scavenging container that holds a scavenger comprising at least one selected from the group consisting of soda lime, slaked lime, and CaO.

Description

Technical Field

[0001] The present disclosure relates to a method for recovering platinum group metals, a method for manufacturing a platinum group metal-containing film, and a film forming apparatus. This application claims priority based on Japanese Application No. 2020-095296 filed on June 1, 2020, and incorporates all the descriptions described in the above Japanese application.

Background Art

[0002] A method of forming a metal-containing film such as ruthenium on the surface of a substrate using the CVD (Chemical Vapor Deposition) method is known. In the formation of the metal-containing film, a source gas of an organometallic compound is introduced into the film forming chamber, and a metal-containing film is formed on the surface of the substrate accommodated in the film forming chamber. In this process, it is considered that about 10% of the organometallic compounds introduced into the chamber form a metal film on the surface of the substrate. The remaining organometallic compounds are discharged from the exhaust pipe of the film forming chamber and also deposited in the film forming chamber.

[0003] In order to increase the recovery efficiency of precious metals such as ruthenium in film formation, it has been proposed to trap metal compounds discharged from the exhaust pipe in the film forming process. Patent Document 1 describes a CVD thin film forming process including a step of recovering an organometallic compound by bringing exhaust gas containing reaction products and unreacted source gas generated in the film forming process into contact with a solvent or an adsorbent, and then a step of separating and purifying the organometallic compound.

[0004] In addition, a dry cleaning method for removing deposits in a film formation chamber using a chlorine-based or fluorine-based cleaning gas is known. However, for safety reasons, the cleaning gas exhausted from the film formation chamber during cleaning cannot be introduced into a trap for capturing metal compounds in the source gas. Therefore, the metal compounds contained in the cleaning gas have not been recovered. Thus, in Patent Document 2, it has been proposed to suppress the number of dry cleaning times or eliminate the dry cleaning process itself by making the inside of the film formation chamber have a specific structure.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, while using an existing film formation chamber, there is no method for performing dry cleaning in the film formation chamber and recovering precious metals contained in the cleaning gas, and there is a limit to the recovery efficiency of precious metals used in film formation.

[0007] An object of the present disclosure is to provide a method for safely recovering precious metals contained in a cleaning gas. Another object of the present disclosure is to provide a method for manufacturing a metal film and a film formation apparatus with high precious metal recovery efficiency.

Means for Solving the Problems

[0008] The method for recovering platinum group metals according to the present disclosure is a method for introducing a raw material gas containing platinum group metals into a film forming chamber, forming a platinum group metal-containing film on the surface of a substrate accommodated in the film forming chamber, and then recovering the platinum group metals present in the film forming chamber, comprising: (i) a step of introducing a cleaning gas containing fluorine into the film forming chamber from which the substrate has been removed; (ii) a step of introducing the cleaning gas discharged from the film forming chamber into a capture container holding a capture agent composed of at least one selected from the group consisting of soda lime, slaked lime, and CaO.

[0009] Further, the method for manufacturing a platinum group metal-containing film according to the present disclosure comprises: (I) a step of introducing a raw material gas containing platinum group metals into a film forming chamber and forming a platinum group metal-containing film on the surface of a substrate accommodated in the film forming chamber; (II) a step of taking out the substrate on which the platinum group metal-containing film has been formed from the film forming chamber; (III) a step of recovering the platinum group metals present in the film forming chamber, wherein the step (III) of recovering the platinum group metals present in the film forming chamber is carried out by the above-described method for recovering platinum group metals.

[0010] Further, the film forming apparatus according to the present disclosure comprises: a film forming chamber for forming a thin film on the surface of a substrate; a gas supply mechanism connected to the film forming chamber; a gas discharge mechanism connected to the film forming chamber; and a control unit for controlling the film forming chamber, the gas supply mechanism, and the gas discharge mechanism, wherein the gas supply mechanism comprises: a first supply pipe for supplying a raw material gas containing platinum group metals to the film forming chamber; and a second supply pipe for supplying a cleaning gas containing fluorine to the film forming chamber, wherein the gas discharge mechanism comprises: A first exhaust pipe connecting the film forming chamber and a first capturing device capable of capturing platinum group metals contained in the source gas discharged from the film forming chamber. A second exhaust pipe connecting the film forming chamber and a second capturing device holding a capturing agent capable of capturing platinum group metals contained in the cleaning gas discharged from the film forming chamber.

Advantages of the Invention

[0011] According to the method for recovering platinum group metals of the present disclosure, platinum group metals contained in the cleaning gas can be recovered. Further, according to the method for manufacturing a platinum group metal-containing film and the film forming apparatus of the present disclosure, it is possible to recover platinum group metals in the cleaning gas, and the recovery efficiency of platinum group metals is high.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0013] As used herein, the term "platinum group metal" does not mean only the simple substance of the platinum group metal, but means chemical species containing a platinum group metal, including ions, compounds and complexes. For example, the term "ruthenium" does not mean only the simple substance of metallic ruthenium, but means chemical species containing ruthenium, including ruthenium ions, ruthenium compounds and ruthenium complexes. However, this is not the case when specific compound names (e.g., ruthenium fluoride, ruthenium oxide, etc.) are described.

[0014] [Summary of Embodiments] The method for recovering a platinum group metal according to the present disclosure is a method for introducing a source gas containing a platinum group metal into a film forming chamber, forming a platinum group metal-containing film on the surface of a substrate accommodated in the film forming chamber, and then recovering the platinum group metal present in the film forming chamber, comprising: (i) a step of introducing a cleaning gas containing fluorine into the film forming chamber from which the substrate has been removed; (ii) a step of introducing the cleaning gas discharged from the film forming chamber into a capture container holding a capture agent composed of at least one selected from the group consisting of soda lime, slaked lime and CaO.

[0015] Conventionally, there has been no known method for safely recovering precious metals contained in a cleaning gas, and the precious metals contained in the cleaning gas have not been recovered. Further, there has been a demand for a method for manufacturing a metal film and a film forming apparatus having excellent recovery efficiency of precious metals. The inventors have repeatedly studied this problem and conceived to provide an exhaust pipe for discharging a cleaning gas during cleaning separately from an exhaust pipe for discharging a source gas during film formation in the formation of a platinum group metal film. Furthermore, by connecting a capture device containing a capture agent capable of capturing a platinum group metal (platinum group metal fluoride) fluorinated by a cleaning gas containing fluorine to such a pipe, it has become possible to recover the platinum group metal contained in the cleaning gas that has conventionally been discarded, and it has been confirmed that the recovery efficiency of the platinum group metal in the method for manufacturing a platinum group metal film can be improved.

[0016] In the method for recovering platinum group metals according to the present disclosure, (i) a step of introducing a cleaning gas containing fluorine into the film formation chamber from which the substrate has been removed, and (ii) a step of introducing the cleaning gas discharged from the film formation chamber into a second capture container holding a capture agent composed of at least one selected from the group consisting of soda lime, slaked lime, and CaO. With this configuration, the cleaning gas can capture the platinum group metals contained in the cleaning gas without passing through the first capture device capable of capturing the platinum group metals contained in the source gas. With this configuration, the platinum group metals contained in the cleaning gas can be recovered without safety problems.

[0017] In the method for recovering platinum group metals, the capture agent may be soda lime. When the capture agent is soda lime, it is excellent in the recovery efficiency of platinum group metals fluorinated by the cleaning gas, can surely detoxify the cleaning gas containing fluorine, and is excellent in safety.

[0018] In the method for recovering platinum group metals, the platinum group metal may be ruthenium or osmium. When the platinum group metal is ruthenium or osmium, a high-quality thin film with few defects can be obtained, and dry cleaning can be performed at a relatively low temperature in the recovery process.

[0019] In the method for recovering platinum group metals, ClF3 can be used as the cleaning gas. ClF3 has much experience as a dry cleaning gas in the film formation of platinum group metals and can surely perform dry cleaning under mild conditions.

[0020] In the method for recovering platinum group metals, after steps (i) and (ii), (iii) a step of extracting the platinum group metal from the capture agent can be further provided. In step (iii), the platinum group metal is separated from the capture agent as a metal compound, and after being subjected to treatments such as purification, it can be used again as a film formation raw material.

[0021] In the method for recovering the platinum group metal, after removing the capture container from the film forming apparatus, a step of introducing a strong acid into the capture agent to extract the platinum group metal fluoride adsorbed on the capture agent as an aqueous solution of the platinum group metal can be included. According to such a step, it is possible to recover the platinum group metal from the capture agent in a simple step using general-purpose materials, and the practical compatibility is excellent.

[0022] The method for manufacturing a platinum group metal-containing film according to the present disclosure (I) A step of introducing a source gas containing a platinum group metal into a film forming chamber and forming a platinum group metal-containing film on the surface of a substrate accommodated in the film forming chamber; (II) A step of taking out the substrate on which the platinum group metal-containing film has been formed from the film forming chamber; (III) A step of recovering the platinum group metal present in the film forming chamber, and The step (III) of recovering the platinum group metal present in the film forming chamber can be carried out by the method for recovering the platinum group metal.

[0023] According to the above manufacturing method, the film forming step of the platinum group metal-containing film, the step of taking out the substrate, and the step of recovering the platinum group metal present in the film forming chamber can be continuously carried out as a series of steps. Further, it is possible to recover the platinum group metal without changing the configuration of the existing film forming chamber. Therefore, it is possible to improve the recovery efficiency of the platinum group metal as a whole of the manufacturing method while eliminating the need for changing or readjusting the regulation of the film forming step.

[0024] In the above manufacturing method, (I) the step of forming the platinum group metal-containing film and (II) the step of taking out the substrate from the film forming chamber may be repeatedly carried out a plurality of times in this order, and then (III) the step of recovering the platinum group metal present in the film forming chamber may be carried out. By adopting such a configuration, it is possible to reduce the man-hour without performing dry cleaning more than necessary, and to suppress the usage amount of raw materials such as dry cleaning gas.

[0025] The film forming apparatus according to the present disclosure includes a film forming chamber for forming a thin film on the surface of a substrate, a gas supply mechanism connected to the film forming chamber, a gas discharge mechanism connected to the film forming chamber, and a control unit for controlling the film forming chamber, the gas supply mechanism, and the gas discharge mechanism. The gas supply mechanism includes a first supply pipe for supplying a source gas containing a platinum group metal to the film forming chamber, and a second supply pipe for supplying a cleaning gas containing fluorine to the film forming chamber. The gas discharge mechanism includes a first exhaust pipe and a second exhaust pipe. The first exhaust pipe connects the film forming chamber and a first capture device capable of capturing the platinum group metal contained in the source gas discharged from the film forming chamber. The second exhaust pipe connects the film forming chamber and a second capture device holding a capture agent capable of capturing the platinum group metal contained in the cleaning gas discharged from the film forming chamber. According to the film forming apparatus of the present disclosure, the above-described method for recovering a platinum group metal and the above-described method for manufacturing a platinum group metal-containing film can be preferably implemented.

[0026] In the above manufacturing method, the second capture device can be made removable from the second exhaust pipe. By making the second capture device removable, it becomes possible to take out the platinum group metal at a timing independent of the film forming process at a location different from the installation locations of the film forming chamber and the gas supply mechanism. Further, it becomes possible to easily replace the second capture device. For example, by using while replacing a plurality of capture devices, it is possible to recover the platinum group metal without affecting the time management of the film forming process.

[0027] [Specific Examples of Embodiments] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated.

[0028] [Film Forming Apparatus] FIG. 1 is a diagram showing an overview of a connection state by piping in one embodiment of a film forming apparatus of the present disclosure. According to the film forming apparatus of the present disclosure, a platinum group metal-containing film such as a ruthenium-containing film or an osmium-containing film can be formed. Here, as an example, Ru3(CO) 12 gas is used, and an example using ClF3 gas as a cleaning gas containing fluorine is shown.

[0029] The film forming apparatus 1 is a film forming apparatus for forming a ruthenium-containing film by CVD method. Referring to FIG. 1, the film forming apparatus 1 includes a film forming chamber 10, a gas supply mechanism 20 for supplying a raw material gas and a cleaning gas to the film forming chamber 10, and a gas discharge mechanism 50 for discharging the raw material gas and the cleaning gas from the film forming chamber 10. Referring to FIG. 2, the film forming chamber 10, the gas supply mechanism 20, and the gas discharge mechanism 50 are controlled by a control unit 100.

[0030] The film forming chamber 10 may be a single wafer type film forming chamber or a batch type film forming chamber as long as it has a function of forming a ruthenium-containing film by CVD method. The film forming chamber 10 includes a gate (not shown) for loading and unloading the substrate to be processed, and a heater (not shown) for setting the inside of the chamber to a predetermined temperature.

[0031] Referring to FIG. 1, the film forming chamber 10 is connected to the gas supply mechanism 20 via a first supply pipe 91 and a second supply pipe 92 of the gas supply mechanism 20. The first supply pipe 91 is configured to supply a raw material gas containing ruthenium for forming a ruthenium-containing film by CVD method to the film forming chamber 10. The second supply pipe 92 is configured to supply a cleaning gas containing fluorine to the film forming chamber 10.

[0032] In the embodiment shown in FIG. 1, the first supply pipe 91 and the second supply pipe 92 are separately connected to the film forming chamber 10. However, the first supply pipe 91 and the second supply pipe 92 may be joined upstream of the film forming chamber 10 so that there is only one gas supply port provided in the film forming chamber 10. When the first supply pipe 91 and the second supply pipe 92 are joined upstream of the film forming chamber 10, valves are provided in each of the first supply pipe 91 and the second supply pipe 92 so that it is possible to switch which of the first supply pipe 91 and the second supply pipe 92 supplies the gas.

[0033] The film forming chamber 10 is connected to the gas discharge mechanism 50 via the first exhaust pipe 75 and the second exhaust pipe 76 of the gas discharge mechanism 50. The first exhaust pipe 75 is provided to discharge the gas discharged from the film forming chamber 10 in the film forming process. The second exhaust pipe 76 is provided to exhaust the gas discharged from the film forming chamber 10 in the cleaning process.

[0034] In the embodiment shown in FIG. 1, the first exhaust pipe 75 and the second exhaust pipe 76 are separately connected to the film forming chamber 10. However, the gas discharge port of the film forming chamber 10 may be made into one, and the first exhaust pipe 75 and the second exhaust pipe 76 may be branched downstream thereof.

[0035] The gas supply mechanism 20 will be described. The gas supply mechanism 20 is a mechanism for supplying a raw material gas for forming a ruthenium-containing film by CVD method and a cleaning gas for cleaning the film forming chamber 10 to the film forming chamber 10. The gas supply mechanism 20 has a film forming raw material container 45 that houses the solid film forming raw material P as Ru3(CO) 12 is provided. A heater 46 is provided around the film forming raw material container 45. Ru3(CO) housed in the film forming raw material container 45 12 is heated by the heater 46 and vaporized to Ru3(CO) 12It becomes gas (ruthenium carbonyl gas). A carrier gas supply pipe 25 for supplying CO gas as a carrier gas is inserted into the film-forming raw material container 45 from above. A carrier gas supply source 24 for supplying CO gas is connected to the carrier gas supply pipe 25. Further, a raw material gas supply pipe 26 is inserted into the film-forming raw material container 45. A mass flow controller 31 for flow control and valves 44a and 44b before and after it are provided in the carrier gas supply pipe 25. Further, a flow meter 35 for grasping the amount of Ru3(CO) 12 gas and a valve 44c whose opening and closing can be adjusted based on the measured value of the flow meter 35 are provided in the raw material gas supply pipe 26.

[0036] The gas supply mechanism 20 includes an additional gas supply source 23 that supplies Ar, which is a dilution gas, and an additional gas supply pipe 27. The additional gas supply pipe 27 connects the additional gas supply source 23 to the raw material gas supply pipe 26 and the first supply pipe 91. A mass flow controller 32 for flow control and valves 43a and 43b before and after it are provided on the additional gas supply source 23 side of the additional gas supply pipe 27.

[0037] With the above configuration, the raw material gas containing Ru3(CO) 12 supplied from the film-forming raw material container 45 is conveyed by CO gas, which is a carrier gas, mixed with Ar gas, and can be supplied into the film-forming chamber 10 through the first supply pipe 91. Note that the carrier gas supply pipe 25 may be branched so that CO gas is used as a counter gas and introduced into the film-forming chamber 10 separately from the raw material gas.

[0038] The gas supply mechanism 20 includes a cleaning gas supply source 22 that supplies ClF3 gas used as a cleaning gas, and a cleaning gas supply pipe 28. The cleaning gas supply pipe 28 connects the cleaning gas supply source 22 to the carrier gas supply pipe 29 and the second supply pipe 92. A mass flow controller 33 for flow control and valves 42a and 42b before and after it are provided on the cleaning gas supply source 22 side of the cleaning gas supply pipe 28.

[0039] The cleaning gas ClF3 gas is transported by the Ar gas supplied as a carrier gas from the carrier gas supply source 21. One end of the carrier gas supply pipe 29 is connected to the carrier gas supply source 21, and the other end of the carrier gas pipe 29 is connected to the cleaning gas supply pipe 28 and the second supply pipe 92. A mass flow controller 34 for flow control and valves 41a and 41b before and after it are provided on the carrier gas supply source 21 side of the carrier gas supply pipe 29.

[0040] With the above configuration, the ClF3 gas supplied from the cleaning gas supply source 22 can be carried by the Ar gas and supplied into the film forming chamber 10 through the second supply pipe 92.

[0041] The gas discharge mechanism 50 will be described. The gas discharge mechanism 50 is a mechanism for discharging the raw material gas after being used for film formation and the cleaning gas after dry cleaning from the film forming chamber 10. The gas discharge mechanism 50 includes a first capture device 51 connected to the film forming chamber 10 by a first exhaust pipe 75. The first capture device 51 can capture ruthenium contained in the raw material gas discharged from the film forming chamber 10. A specific embodiment of the first capture device 51 is, for example, a cold trap. When the first capture device 51 is a cold trap, water can be used as the refrigerant. Alternatively, instead of using a refrigerant, a vacuum cold trap having a cooling surface can be used as the first capture device 51.

[0042] A dry pump 61 is connected to the first capture device 51 via a pipe. The dry pump 61 exhausts from the film forming chamber 10 based on the measured value of a pressure gauge (not shown), and also maintains the inside of the film forming chamber 10 at a predetermined pressure.

[0043] The dry pump 61 is connected to the decontamination device 80 via a pipe. The decontamination device 80 decontaminates the raw material gas containing CO gas and ruthenium that could not be captured by the first capture device 51. A specific embodiment of the decontamination device 80 is, for example, a combustion type decontamination device. The CO gas conveyed to the decontamination device 80 is incinerated in the decontamination device 80 and discharged into the atmosphere as CO2 gas. As the decontamination device, in addition to the combustion type decontamination device, a heating type decontamination device such as a plasma type decontamination device or a heater type decontamination device can be used.

[0044] In the embodiment of FIG. 1, the first exhaust pipe 75 is connected to the first capture device 51, but an auxiliary capture device can also be provided in the middle of the first exhaust pipe 75. Further, a dry pump can be arranged upstream of the first capture device 51 so that the first capture device 51 is under atmospheric pressure.

[0045] The gas discharge mechanism 50 includes a second capture device 52 connected to the film forming chamber 10 by a second exhaust pipe 76. The second capture device 52 is a dry decontamination device that holds the solid granular capture agent 53 in a container made of, for example, stainless steel. The capture agent 53 is a capture agent capable of capturing ruthenium contained in the cleaning gas discharged from the film forming chamber 10 during cleaning of the film forming chamber 10.

[0046] The capture agent 53 is preferably at least one selected from the group consisting of, for example, soda lime, slaked lime, and CaO (calcium oxide), and more preferably soda lime. By using these substances as the capture agent 53, ruthenium (ruthenium fluoride) fluorinated by the fluorine-based cleaning gas contained in the cleaning gas can be captured as ruthenium oxide. Further, ClF3 can be decontaminated by the capture agent 53.

[0047] The second capture device 52 includes a cleaning gas introduction pipe 77. The cleaning gas introduction pipe 77 is connected to the second exhaust pipe 76 via a flange 54a and is inserted into the capture agent 53. The second capture device 52 also includes an outlet pipe 78. The outlet pipe 78 discharges the gas after decontamination that has passed through the capture agent 53. A flange 54b is provided on the outlet pipe 78. At the positions of the flanges 54a and 54b, the second capture device 52 is detachable from the second exhaust pipe 76. Since the second capture device 52 is detachable from the second exhaust pipe 76, the extraction of ruthenium from the capture agent 53 can be carried out with the second capture device 52 separated from the film forming apparatus 1. That is, the separation and purification of ruthenium from the capture agent 53 can be carried out at a location different from the installation location of the film forming apparatus and at a timing independent of the film forming process.

[0048] In the embodiment of FIG. 1, when the second capture device 52 has not only the function of capturing ruthenium but also the function of decontaminating fluorine compounds, the second capture device 52 does not need to be connected to the decontamination device 80, and there is no need to use expensive stainless steel pipes. As a result, since the fluorine compounds do not mix into the decontamination device 80, corrosion does not occur, and the maintenance frequency can be reduced.

[0049] Next, with reference to FIGS. 1 and 2, the control connections of the embodiment shown in FIG. 1 will be described. Referring to FIG. 2, the film forming apparatus 1 includes a film forming chamber 10, a gas supply mechanism 20, a gas discharge mechanism 50, and a control unit 100.

[0050] The control unit 100 functions as a flow path control device for the film forming apparatus, and controls the entire film forming apparatus from a plurality of gas supply sources and a film forming raw material container through the film forming chamber to the decontamination device. The control unit 100 adjusts the type, mixing ratio, and flow rate of the raw material gas and the cleaning gas supplied from the gas supply mechanism 20 by controlling the opening and closing states of the plurality of valves 41a to 44a, 41b to 44b, 44c included in the gas supply mechanism 20. Further, the control unit 100 receives the measured value signal of the flow meter 35, and adjusts the opening and closing state of the valve 44c according to the measured value. The control unit 100 adjusts the temperature inside the raw material container 45 by controlling the heater 46 included in the gas supply mechanism 20.

[0051] The control unit 100 also controls the operations of the heater, susceptor, gate, etc. provided in the film forming chamber 10 so that film formation according to a predetermined protocol is executed. Regarding these operations, the control unit 100 receives the measured value signals of the temperature sensor, pressure sensor, etc. provided in the film forming chamber 10, and can adjust the on / off, degree, and timing of the operations according to the measured values.

[0052] The control unit 100 also controls the opening and closing states of the plurality of valves 71 to 73 included in the gas discharge mechanism 50. Further, the control unit 100 controls the outputs of the pumps 61, 62 included in the gas discharge mechanism 50. By adjusting the outputs of the pumps 61, 62, the control unit 100 adjusts and maintains the pressure in the film forming chamber 10 and the pipes connected thereto to a predetermined value. By controlling the outputs of the pumps 61, 62, the flow rate and pressure of the raw material gas and the cleaning gas supplied to the film forming chamber 10, and the flow rate and pressure of the raw material gas after film formation and the cleaning gas after cleaning discharged from the film forming chamber 10 are adjusted.

[0053] <Materials used in the film forming method> <Materials used for film formation> In the film-forming apparatus of the present disclosure, the metal film to be formed is a platinum group metal-containing film, and examples of the platinum group metal include ruthenium, osmium, iridium, and platinum. In particular, a ruthenium-containing film or an osmium-containing film is preferable.

[0054] When forming a ruthenium-containing film, various organic and inorganic materials can be used as the ruthenium source gas. For example, ruthenium carbonyl (Ru3(CO) 12 ) can be preferably used. Ru3(CO) 12 gas becomes Ru by thermal decomposition. At this time, it is preferable to use CO gas as the carrier gas for Ru3(CO) 12 gas. By using CO as the carrier gas, the decomposition reaction of Ru3(CO) 12 gas in the processing chamber can be suppressed, and film formation can be performed by supplying it to the substrate to be processed while maintaining the structure of Ru3(CO) 12 as much as possible. Ru3(CO) 12 gas may be reacted with a reaction gas to form a ruthenium-containing film other than the ruthenium film.

[0055] Examples of the ruthenium source gas include, in addition to Ru3(CO) 12 RuO2, Ru(EtCp)2, Ru(DMDB)(CO)3, RuO4(HFE), Ru(HDAC), Ru(PF3), Ru(AMD)2CO, RuCOT, etc., and at least one of these raw materials containing Ru3(CO) 12 can be used.

[0056] The reaction gas when forming a ruthenium-containing film other than the ruthenium film is appropriately selected according to the ruthenium source gas and the ruthenium-containing film to be obtained. Examples of the reaction gas include CO2, O2, H2, SiH4, Si2H6, Si3H8, Si4H 10 , NH3, CH3(NH)NH2, C2H8N2, N2H4, etc., and at least one of these can be used.

[0057] When using CO2, O2, and H2 as reaction gases, a ruthenium film or a ruthenium oxide film can be formed. When using SiH4, Si2H6, Si3H8, Si4H 10 as reaction gases, a ruthenium film containing Si can be formed. When using NH3, CH3(NH)NH2, C2H8N2, N2H4 as reaction gases, a ruthenium film containing N can be formed. Also, a ruthenium film doped with a gas containing a dopant can be formed.

[0058] When forming a ruthenium single film, no reaction gas is used. As a carrier gas for diluting and transporting the source gas when forming a ruthenium single film, an inert gas such as N2 gas or a rare gas can be used. Examples of the rare gas include Ar, He, Ne, Xe, Kr, etc.

[0059] <Materials used for cleaning> In the recovery method and manufacturing method of the present disclosure, a cleaning gas containing fluorine is used as the cleaning gas. As the cleaning gas containing fluorine, ClF3 can be preferably used. Examples of cleaning gases other than ClF3 include F2, F2 / N2 mixed gas, NF3 excited in a plasma state, CF4, C2F6, C3F8, SF6, etc. These cleaning gases containing fluorine can be used alone or in combination of two or more.

[0060] In cleaning, a carrier gas for transporting the above cleaning gas may be used. As the carrier gas, an inert gas such as N2 gas or a rare gas can be used. Examples of the rare gas include Ar, He, Ne, Xe, Kr, etc.

[0061] <Film formation method> With reference to FIGS. 1 to 3, a method for manufacturing a ruthenium-containing film according to an embodiment of the present disclosure will be described. FIG. 3 is a flowchart showing a method for manufacturing a ruthenium-containing film according to an embodiment of the present disclosure. As shown in FIG. 3, the manufacturing method according to the present embodiment includes a step S10 of forming a ruthenium-containing film on a substrate, a step S20 of taking out the substrate from the film-forming chamber, a step S30 of introducing a cleaning gas into the film-forming chamber, and a step S40 of introducing the cleaning gas into a capture container.

[0062] The step S10 of forming a ruthenium-containing film on the substrate will be described. In the film-forming step S10, the following operations are executed by the control unit 100.

[0063] In the film-forming step S10, the substrate is transported into the film-forming chamber 10 of the film-forming apparatus 1, and the heater provided in the film-forming chamber 10 and the dry pump 61 of the gas discharge mechanism 50 are operated to set the inside of the film-forming chamber 10 to a predetermined temperature and pressure. At this time, the valves 43a and 43b may be opened, and Ar, which is a carrier gas, may be introduced into the film-forming chamber 10 as a purge gas. The pressure inside the film-forming chamber 10 in the film-forming step S10 can be, for example, 10 to 100 Pa, and the temperature can be, for example, 120 to 250°C.

[0064] Simultaneously or subsequently, the heater 46 of the film-forming raw material container 45 is operated to heat and vaporize the film-forming raw material P (Ru3(CO) 12 )). Further, the valves 44a and 44b are opened, and CO gas is blown into the film-forming raw material container 45 through the carrier gas supply pipe 25. The Ru3(CO) 12 gas in the film-forming raw material container 45 is supplied into the film-forming chamber 10 through the raw material gas supply pipe 26 and the first supply pipe 91 in a state carried by the CO gas. The flow rate of the Ru3(CO) 12 gas is measured by the flow meter 35, and the control unit 100 can change the opening / closing state of the valve 44c according to the measured value. Further, the control unit 100 adjusts the opening / closing states of the valves 43a and 43b to supply an additional gas (dilution gas) from the additional gas supply source 23. The flow rate of the raw material gas and the mixing ratio of the raw material gas and the dilution gas can be appropriately set according to the target film thickness of the ruthenium-containing film, the type of the substrate, and the like.

[0065] By the above operation, a ruthenium-containing film having a predetermined film thickness is formed on the surface of the substrate placed in the film formation chamber 10.

[0066] In the film formation step S10, the valves 41a, 41b, 42a, and 42b of the gas supply mechanism 20 are closed, and the gas from the second supply pipe 92 to the film formation chamber 10 is blocked.

[0067] While the film formation step S10 is being carried out, the valve 71 is open and the valve 72 is closed. That is, in the film formation step S10, the gas exhausted from the film formation chamber 10 is discharged through the first exhaust pipe 75. The gas exhausted from the film formation chamber 10 in the film formation step S10 contains the raw material gas and the dilution gas. When a reaction gas is used as the additional gas, the exhaust gas also contains the reaction product of ruthenium and the reaction gas.

[0068] The exhaust gas in the film formation step S10 passes through the first capture device 51, and the ruthenium contained in the exhaust gas is captured in the first capture device 51. The ruthenium captured in the first capture device 51 is generally considered to be about 70% of the ruthenium used as the film formation raw material. The exhaust gas after passing through the first capture device 51 mainly contains CO gas.

[0069] The exhaust gas that has passed through the first capture device 51 reaches the detoxification device 80 via the dry pump 61. In the detoxification device 80, the exhaust gas is detoxified, for example, by incineration and precipitation separation, and discharged into the atmosphere.

[0070] In the film formation step S10, the valves 72 and 73 of the gas discharge mechanism 50 are closed, and the pump 62 is stopped. That is, the exhaust gas in the film formation step S10 is not discharged to the second exhaust pipe 92.

[0071] The step S20 of taking out the substrate from the film formation chamber will be described. Following the film formation step S10, the substrate with the ruthenium-containing film formed on its surface is taken out from the film formation chamber 10. This step can be carried out by a known method and is not particularly limited. For example, in the film formation step S10, a raw material gas is supplied into the film formation chamber 10, and after a predetermined time (e.g., 1 to 600 seconds) has elapsed, the substrate is taken out from the film formation chamber 10, and the film formation chamber 10 can be made into a state where no substrate exists.

[0072] After repeating the film formation step S10 and the taking-out step S20 one or more times, it is determined whether to clean the inside of the film formation chamber. Specifically, for example, it is determined whether the deposition amount of ruthenium in the film formation chamber 10 exceeds the allowable amount (Q10). The determination criterion may be, for example, the number of repetitions of film formation (the number of film-formed substrates), or the elapsed time since the start of film formation. When it is determined that the deposition amount of ruthenium in the film formation chamber 10 is within the allowable range (NO in Q10), the film formation step S10 and the taking-out step S20 are carried out again.

[0073] On the other hand, when it is determined that the deposition amount of ruthenium in the film formation chamber 10 exceeds the allowable range (YES in Q10), a method for recovering the ruthenium existing in the film formation chamber is carried out. Specifically, a step S30 of introducing a cleaning gas into the film formation chamber and a step S40 of introducing the cleaning gas into a capture container are carried out.

[0074] The cleaning gas introduction step S30 is carried out in a state where no substrate exists in the film formation chamber 10 after the step S20 of taking out the substrate from the film formation chamber. The inside of the film formation chamber 10 is heated to a predetermined temperature, for example, 150 to 250°C, by the heater of the film formation chamber 10.

[0075] In the cleaning gas introduction step S30, the valves 43a, 43b, 44a, 44b, 44c of the gas supply mechanism 20 are closed, and the gas from the first supply pipe 91 to the film formation chamber 10 is shut off.

[0076] In the cleaning gas introduction step S30, the valve 71 of the gas discharge mechanism 50 is closed, and the cleaning gas is not discharged from the first exhaust pipe 75. Since there is a risk of explosion when introducing the cleaning gas into the first capture device 51 that has captured ruthenium or the like, introducing the cleaning gas into the first exhaust pipe 75 is avoided.

[0077] In the cleaning gas introduction step S30, the dry pump 62 operates. First, the valves 41a and 41b are opened, and a carrier gas (e.g., Ar gas) is supplied from the carrier gas supply source 21 to purge the inside of the film formation chamber 10. The pressure inside the film formation chamber 10 is adjusted to, for example, 10 to 1000 Pa. In this state, ClF3, which is the cleaning gas, is introduced into the film formation chamber 10 to perform dry cleaning.

[0078] Although not particularly limited by theory, the following chemical reaction occurs during dry cleaning, and ruthenium present in the film formation chamber 10 is discharged as ruthenium fluoride gas and is considered to be the case. Ru + 5 / 3ClF3 → RuF5↑ + 5 / 6Cl2↑

[0079] During dry cleaning, the valves 41a and 41b are opened, and while flowing the Ar gas, which is the carrier gas, the valves 42a and 42b are further opened to supply ClF3 gas. The flow rate of the ClF3 gas can be appropriately set according to the internal volume of the film formation chamber, the film thickness of the ruthenium film accumulated in the film formation chamber, and the like. The supply time of the ClF3 gas is preferably in the range of 1 to 60 seconds, and the number of repetitions is preferably about 1 to 100 times.

[0080] Following the cleaning gas introduction step S30, or simultaneously with the cleaning gas introduction step S30, valves 73, 79a, and 79b are opened to introduce the cleaning gas into the second capture device 52 (S40). The second capture device 52 is provided downstream of the dry pump 62, that is, under atmospheric pressure. The cleaning gas introduced into the second capture container 52 is introduced into the capture agent 53 through the cleaning gas introduction pipe 77 and contacts the capture agent 53.

[0081] The cleaning gas introduced into the capture agent 53 contains ClF3 and RuF5 (ruthenium fluoride). The capture agent 53 is at least one selected from the group consisting of soda lime, slaked lime, and CaO (calcium oxide). By capturing ClF3 and ruthenium fluoride by the capture agent, the cleaning gas is detoxified.

[0082] Note that soda lime is also called sodium lime, and is a strongly basic solid granular substance mainly composed of calcium hydroxide and containing water, potassium hydroxide, and sodium hydroxide. Examples of the composition of soda lime include those containing 75 wt% to 85 wt% of calcium hydroxide, 10 wt% to 20 wt% of water, 1 wt% to 5 wt% of potassium hydroxide, and 1 wt% to 5 wt% of sodium hydroxide.

[0083] Although not particularly bound by theory, the following chemical reaction occurs upon contact between ruthenium fluoride and the capture agent, and ruthenium fluoride is considered to become ruthenium oxide and be immobilized on the capture agent. Ca(OH)2 + RuF5 → CaF2 + RuO2 + CaCl2

[0084] The cleaning gas detoxified in the second capture device 52 is discharged into the atmosphere through the exhaust pipe 78 of the second capture device 52.

[0085] After the cleaning gas introduction step S30 into the film formation chamber 10 and the cleaning gas introduction step S40 into the second capture device 52 are repeated one or more times, it is determined whether to replace the capture device. Specifically, it is determined whether the replacement timing of the capture container 52 has been reached (Q20). The determination criteria may be, for example, the number of repetitions of dry cleaning or the elapsed time since the start of use of the capture device. Also, based on the detection signal from the gas detector (e.g., Cl2 sensor) provided in the second capture device 52, the replacement timing can be determined. If it is determined that the replacement timing of the container has not been reached (NO in Q20), the cleaning gas introduction step S30 into the film formation chamber 10 and the cleaning gas introduction step S40 into the second capture device 52 are carried out again.

[0086] On the other hand, if it is determined that the replacement timing of the container has been reached (YES in Q20), the valves 79a and 79b are closed, the piping is blocked at the flanges 54a and 54b, and the second capture device 52 is removed from the second exhaust pipe 76 (S50). Preferably, the second capture device 52 is provided with casters or the like so that the removed capture device can be easily moved.

[0087] After the second capture device 52 is removed from the second exhaust pipe 76, ruthenium is taken out from the capture agent 53 accommodated in the second capture device 52 (S60). The ruthenium extraction step S60 can be carried out at a location different from the installation location of the film forming apparatus and independently of the production of the ruthenium film.

[0088] Specifically, the ruthenium extraction step S60 can be carried out, for example, by introducing a strong acid such as hydrochloric acid or sulfuric acid into the capture agent 53 and causing the ruthenium oxide immobilized on the capture agent to flow out as an aqueous solution of ruthenium chloride.

[0089] The ruthenium chloride taken out as described above can be used again for film formation as a ruthenium precursor after undergoing a predetermined treatment.

[0090] <Other Embodiments> FIG. 4 shows a film forming apparatus 100 which is another embodiment of the film forming apparatus of the present disclosure. In the film forming apparatus 100, the film forming chamber 10 and the gas supply mechanism 20 are the same as those of the film forming apparatus 1 shown in FIG. 1, and the description thereof is omitted.

[0091] The gas supply mechanism 500 in the film forming apparatus 100 includes a first exhaust pipe 75 and a second exhaust pipe 76. The downstream of the first exhaust pipe 75 is the same as that of the film forming apparatus 1, and the description thereof is omitted.

[0092] The second exhaust pipe 76 connects the film forming chamber 10 and the second capture device 520. The second capture device 520 includes a cleaning gas introduction pipe 770. The cleaning gas introduction pipe 770 is connected to the second exhaust pipe 76 via a flange 540a and is inserted into the capture agent 530. The second capture device 520 also includes an outlet pipe 780. The outlet pipe 780 discharges the gas after detoxification that has passed through the capture agent 530. A flange 540b is provided on the outlet pipe 780. In the flange 540a, the second capture device 520 is detachable from the second exhaust pipe 76. A pipe 731 is connected downstream of the flange 540b. That is, the second capture device 520 is detachable from the second exhaust pipe 76 and the pipe 731 at the positions of the flanges 540a and 540b.

[0093] The second capture device 520 is connected to a dry pump 620 via a pipe 731. That is, when the dry pump 620 is operated to perform dry cleaning, the second capture device 520 is in a reduced pressure atmosphere. The downstream of the dry pump 620 is connected to a detoxification device 800, and the gas discharged from the dry pump 620 is detoxified by the detoxification device 800 and released into the atmosphere.

[0094] In the embodiment of FIG. 4, since the second capture device 520 is connected to the pest control device 800, the pest control function for fluorine compounds is unnecessary and only the capture of ruthenium is required. In this case, since the alkaline agent in the second capture device 520 reacts with the fluorine compound, the corrosion of the pest control device 800 can be suppressed by reducing the amount of fluorine compound mixed into the pest control device 800.

[0095] <Example> Hereinafter, examples will be described. Using the film forming apparatus shown in FIG. 1, a ruthenium film was formed by the above-described film forming method using Ru3(CO) 12 gas and CO gas. The ruthenium film deposited on the wall of the film forming chamber was dry cleaned using ClF3 as a cleaning gas. In this example, the cleaning with ClF3 was performed every time the film forming process was carried out, but the determination of the cleaning may be made according to the thickness of the ruthenium film deposited on the wall of the film forming chamber. During dry cleaning, ruthenium was captured using a capture device that houses soda lime in a stainless steel outer cylinder container.

[0096] After performing dry cleaning, the capture device was removed from the exhaust pipe of the cleaning gas, and the appearance of the capture agent in the capture device was observed. The capture agent had changed color to blackish brown, and it was confirmed that ruthenium fluoride was immobilized. Hydrochloric acid was injected into the capture agent, and ruthenium was recovered as an aqueous solution of ruthenium chloride.

[0097] The ruthenium recovered in dry cleaning was calculated to be about 10% of the ruthenium raw material used for film formation. In the conventional film forming method, since the ruthenium removed by dry cleaning was not recovered, it was confirmed that in this example, the recovery efficiency of ruthenium was improved by about 10% compared to the conventional method.

[0098] The embodiments disclosed this time should be understood as illustrative in all respects and not restrictive in any way. The scope of the present invention is defined by the claims rather than the above description, and it is intended that all modifications within the meaning and scope equivalent to the claims be included.

Industrial Applicability

[0099] The method for recovering platinum group metals, the method for manufacturing a platinum group metal-containing film, and the film forming apparatus of the present disclosure can be particularly advantageously applied in semiconductor manufacturing by the CVD method.

Explanation of Signs

[0100] 1, 100 Film forming apparatus 10 Film forming chamber 20 Gas supply mechanism 21 Carrier gas supply source 22 Cleaning gas supply source 23 Additional gas supply source 24 Carrier gas supply source 25 Carrier gas supply pipe 26 Source gas supply pipe 27 Additional gas supply pipe 28 Cleaning gas supply pipe 29 Carrier gas supply pipe 31, 32, 33, 34 Mass flow controller 35 Flow meter 41a, 41b, 42a, 42b, 43a, 43b, 44a, 44b, 71, 72, 73, 79a, 79b Valve 45 Film forming raw material container 46 Heater 50, 500 Gas discharge mechanism 51, 52, 520 Capture device 53, 530 Capture agent 54a, 54b, 540a, 540b Flange 61, 62, 620 Dry pump 731 Pipe 75, 76 Exhaust pipe 77, 770 Cleaning gas introduction pipe 78, 780 Exhaust Piping 80, 800 Decontamination Device 91, 92 Supply Piping

Claims

1. A method for recovering ruthenium present in a film formation chamber, comprising introducing a raw material gas containing gasified ruthenium carbonyl into the film formation chamber, forming a ruthenium-containing film on the surface of a substrate accommodated in the film formation chamber, and then recovering ruthenium present in the film formation chamber, (i) a step of introducing a cleaning gas containing fluorine into the film formation chamber from which the substrate has been removed; (ii) a step of introducing the cleaning gas discharged from the film formation chamber into a capture container holding a capture agent composed of at least one selected from the group consisting of soda lime, slaked lime, and CaO; After the steps (i) and (ii), (iii) a step of extracting ruthenium from the capture agent, The step (iii) of extracting ruthenium from the capture agent is a step of removing ruthenium immobilized as ruthenium oxide in the capture agent as a ruthenium salt solution by introducing a strong acid into the capture agent after removing the capture container from the film forming apparatus. A method for recovering ruthenium.

2. The method for recovering ruthenium according to claim 1, wherein the capture agent is soda lime.

3. wherein the cleaning gas is ClF ３ The method for recovering ruthenium according to claim 1 or claim 2, wherein the cleaning gas is ClF

4. (I) a step of introducing a raw material gas containing gasified ruthenium carbonyl into a film formation chamber and forming a ruthenium-containing film on the surface of a substrate accommodated in the film formation chamber; (II) a step of removing the substrate on which the ruthenium-containing film has been formed from the film formation chamber; (III) a step of recovering ruthenium present in the film formation chamber, The step (III) of recovering ruthenium present in the film formation chamber is carried out by the method for recovering ruthenium according to any one of claims 1 to 3. A method for producing a ruthenium-containing film.

5. (I) The step of forming the ruthenium-containing film and (II) the step of removing the substrate from the film formation chamber are repeatedly carried out a plurality of times in this order, After that, (III) a step of recovering ruthenium present in the film formation chamber is carried out. The method for producing a ruthenium-containing film according to claim 4.

6. A film formation chamber for forming a thin film on the surface of a substrate, A gas supply mechanism connected to the film formation chamber, A gas discharge mechanism connected to the film formation chamber, A control unit for controlling the film formation chamber, the gas supply mechanism, and the gas discharge mechanism, The gas supply mechanism is, A first supply pipe for supplying a raw material gas containing gasified ruthenium carbonyl to the film forming chamber; A second supply pipe for supplying a cleaning gas containing fluorine to the film forming chamber; and The gas discharge mechanism includes A first exhaust pipe connecting the film forming chamber and a first capture device capable of capturing ruthenium contained in the raw material gas discharged from the film forming chamber; A second exhaust pipe connecting the film forming chamber and a second capture device holding a capture agent which is at least one selected from the group consisting of soda lime, slaked lime, and CaO and capable of capturing ruthenium contained in the cleaning gas discharged from the film forming chamber; and The second capture device is removable from the second exhaust pipe; After removing the second capture device from the second exhaust pipe, ruthenium is removed from the capture agent accommodated in the second capture device; A film forming apparatus.

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