WO2021246340A1 - Method for recovering platinum group metal, method for manufacturing film containing platinum group metal, and film-forming apparatus - Google Patents

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

Platinum group metal recovery method, platinum group metal-containing film manufacturing method and film forming apparatus

The present disclosure relates to a method for recovering a platinum group metal, a method for producing 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 contents described in the Japanese application.

A method of forming a metal-containing film such as ruthenium on the surface of a substrate by using a CVD (Chemical Vapor Deposition) method is known. In the film formation of the metal-containing film, the raw material gas of the organic metal compound is introduced into the film formation chamber, and the metal-containing film is formed on the surface of the substrate housed in the film formation 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 residual organometallic compound is discharged from the exhaust pipe of the film forming chamber and is deposited in the film forming chamber.

In order to improve the recovery efficiency of precious metals such as ruthenium in film formation, it has been proposed to trap the metal compound discharged from the exhaust pipe in the film formation process. Patent Document 1 describes a step of recovering an organic metal compound by contacting an exhaust gas containing a reaction product generated in a film forming step and an unreacted raw material gas with a solvent or an adsorbent, and then a step of recovering the organic metal compound. A CVD thin film forming process comprising a step of separating and purifying is described.

Further, a dry cleaning method for removing deposits in a film forming chamber using a chlorine-based or fluorine-based cleaning gas is known. However, for safety reasons, the cleaning gas exhausted from the film forming chamber during cleaning cannot be introduced into the trap for capturing the metal compound in the raw material gas. Therefore, the metal compound contained in the cleaning gas was not recovered. Therefore, Patent Document 2 proposes to suppress the number of dry cleanings or eliminate the dry cleaning process itself by forming the inside of the film forming chamber with a specific structure.

Japanese Unexamined Patent Publication No. 2001-342566 Japanese Unexamined Patent Publication No. 2011-192661

However, there is no method for performing dry cleaning inside the film forming chamber while using the existing film forming chamber and recovering the noble metal contained in the cleaning gas, and the recovery efficiency of the noble metal used for film forming is not high. There was a limit.

The purpose of this disclosure is to provide a method for safely recovering precious metals contained in cleaning gas. Another object of the present disclosure is to provide a method for producing a metal film having high recovery efficiency of a noble metal and a film forming apparatus.

In the method for recovering a platinum group metal according to the present disclosure, a raw material gas containing a platinum group metal is introduced into a film forming chamber, and a platinum group metal-containing film is formed on the surface of a substrate housed in the film forming chamber. After that, it is a method of recovering the platinum group metal existing in the film forming chamber.
(I) A step of introducing a cleaning gas containing fluorine into the film forming chamber from which the substrate is taken out, and
(Ii) A step of introducing the cleaning gas discharged from the film forming chamber into a trapping container holding a trapping agent consisting of at least one selected from the group consisting of soda lime, slaked lime and CaO. ..

In addition, the method for producing a platinum group metal-containing film according to the present disclosure is as follows.
(I) A step of introducing a raw material 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 housed in the film forming chamber.
(II) A step of taking out the substrate on which the platinum group metal-containing film is formed from the film forming chamber, and
(III) A step of recovering the platinum group metal existing in the film forming chamber is provided.
The step of recovering the platinum group metal existing in the film forming chamber (III) is carried out by the above-mentioned platinum group metal recovery method.

In addition, the film forming apparatus according to the present disclosure is
A film formation chamber for forming a thin film on the surface of the substrate,
A gas supply mechanism connected to the film forming chamber and
A gas discharge mechanism connected to the film forming chamber and
The film forming chamber, the gas supply mechanism, and a control unit for controlling the gas discharge mechanism are provided.
The gas supply mechanism is
The first supply pipe for supplying the raw material 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 is provided.
The gas discharge mechanism is
A first exhaust pipe connecting the film forming chamber and a first capturing device capable of capturing the platinum group metal contained in the raw material gas discharged from the film forming chamber.
A second exhaust pipe connecting the film forming chamber and a second capturing device holding a scavenger capable of capturing the platinum group metal contained in the cleaning gas discharged from the film forming chamber. To prepare for.

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

FIG. 1 is a diagram showing an outline of a connection state by piping in an example of an embodiment of a film forming apparatus. FIG. 2 is a diagram showing an outline of a control connection state in an example of the embodiment of the film forming apparatus. FIG. 3 is a flowchart showing an example of an embodiment of a method for producing a platinum group metal-containing film. FIG. 4 is a diagram showing an outline of a connection state by piping in an example of the embodiment of the film forming apparatus.

As used herein, the term "platinum group metal" does not mean only a simple substance of a platinum group metal, but also means a chemical species containing a platinum group metal, including ions, compounds and complexes. For example, "ruthenium" does not mean only a single metal ruthenium, but a ruthenium-containing chemical species, including ruthenium ions, ruthenium compounds and ruthenium complexes. However, this does not apply when a specific compound name (for example, ruthenium fluoride, ruthenium oxide, etc.) is described.

[Outline of Embodiment]
In the method for recovering a platinum group metal according to the present disclosure, a raw material gas containing a platinum group metal is introduced into a film forming chamber, and a platinum group metal-containing film is formed on the surface of a substrate housed in the film forming chamber. After that, it is a method of recovering the platinum group metal existing in the film forming chamber.
(I) A step of introducing a cleaning gas containing fluorine into the film forming chamber from which the substrate is taken out, and
(Ii) A step of introducing the cleaning gas discharged from the film forming chamber into a trapping container holding a trapping agent consisting of at least one selected from the group consisting of soda lime, slaked lime and CaO. ..

Conventionally, a method for safely recovering the precious metal contained in the cleaning gas has not been known, and the precious metal contained in the cleaning gas has not been recovered. Further, there has been a demand for a metal film manufacturing method and a film forming apparatus having excellent recovery efficiency of precious metals. The inventors have repeatedly studied this problem and came up with the idea of providing an exhaust pipe for discharging the cleaning gas at the time of cleaning, in addition to the exhaust pipe for discharging the raw material gas at the time of forming the platinum group metal film. did. Further, by connecting a catching device containing a catching agent capable of catching a platinum group metal (platinum group metal fluoride) fluorinated by a cleaning gas containing fluorine to such a pipe, cleaning that has been conventionally discarded It has been confirmed that the platinum group metal contained in the gas can be recovered, and the recovery efficiency of the platinum group metal in the method for producing the platinum group metal film can be improved.

In the method for recovering a platinum group metal according to the present disclosure, (i) a step of introducing a cleaning gas containing fluorine into the film forming chamber from which the substrate is taken out, and (ii) from soda lime, slaked lime and CaO. A step of introducing the cleaning gas discharged from the film forming chamber into the second trapping container holding the trapping agent consisting of at least one selected from the group. With this configuration, the platinum group metal contained in the cleaning gas can be captured without the cleaning gas passing through the first capture device capable of capturing the platinum group metal contained in the raw material gas. With this configuration, the platinum group metal contained in the cleaning gas can be recovered without any safety problem.

In the above platinum group metal recovery method, the scavenger may be soda lime. When the scavenger is soda lime, the recovery efficiency of the platinum group metal fluoride fluorided by the cleaning gas is excellent, and the cleaning gas containing fluorine can be reliably detoxified, which is excellent in safety.

In the above method for recovering a platinum group metal, 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.

In the method for recovering a platinum group metal, ClF ₃ can be used as a cleaning gas. ClF ₃ has many achievements as a dry cleaning gas in the film formation of platinum group metals, and can reliably perform dry cleaning under mild conditions.

In the platinum group metal recovery method, after steps (i) and (ii), (iii) a step of extracting the platinum group metal from the scavenger can be further provided. In the step (iii), the platinum group metal is separated from the scavenger as a metal compound, further subjected to a treatment such as purification, and then can be used again as a film forming raw material.

In the above method for recovering a platinum group metal, a step of removing the platinum group metal fluoride adsorbed by the scavenger as a platinum group metal aqueous solution by introducing a strong acid into the scavenger after removing the capture container from the film forming apparatus is performed. Can include. According to such a step, it is possible to recover the platinum group metal from the scavenger by a simple step using a general-purpose material, and the suitability for practical use is excellent.

The method for producing a platinum group metal-containing film according to the present disclosure is as follows.
(I) A step of introducing a raw material 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 housed in the film forming chamber.
(II) A step of taking out the substrate on which the platinum group metal-containing film is formed from the film forming chamber, and
(III) A step of recovering the platinum group metal existing in the film forming chamber is provided.
The step of recovering the platinum group metal existing in the film forming chamber (III) can be carried out by the method of recovering the platinum group metal.

According to the above-mentioned manufacturing method, the step of forming a platinum group metal-containing film, the step of taking out the substrate, and the step of recovering the platinum group metal existing 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 in the manufacturing method, while it is not necessary to change or readjust the regulation of the film forming process.

In the above-mentioned 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 are repeated a plurality of times in this order, and then (III). ) It may be configured so that the step of recovering the platinum group metal existing in the film forming chamber is carried out. With such a configuration, it is possible to reduce the number of man-hours and reduce the amount of raw materials used such as dry cleaning gas without performing dry cleaning more than necessary.

The film forming apparatus according to the present disclosure includes a film forming chamber for forming a thin film on the surface of the substrate, a gas supply mechanism connected to the film forming chamber, and a gas discharge mechanism connected to the film forming chamber. The film forming chamber, the gas supply mechanism, and a control unit for controlling the gas discharge mechanism are provided. The gas supply mechanism includes a first supply pipe that supplies a raw material gas containing a platinum group metal to the film forming chamber, and a second supply pipe that supplies 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 the first capturing device capable of capturing the platinum group metal contained in the raw material gas discharged from the film forming chamber. The second exhaust pipe connects the film forming chamber and a second capturing device that holds a scavenger capable of capturing the platinum group metal contained in the cleaning gas discharged from the film forming chamber. do. According to the film forming apparatus of the present disclosure, the above-mentioned method for recovering a platinum group metal and the above-mentioned method for producing a platinum group metal-containing film can be suitably carried out.

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 is possible to take out the platinum group metal at a timing independent of the film forming process at a place different from the place where the film forming chamber and the gas supply mechanism are installed. In addition, the second capture device can be easily replaced. For example, by using a plurality of capture devices while exchanging them, it is possible to recover the platinum group metal without affecting the time control in the film forming process.

[Specific example of the embodiment]
Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following drawings, the same or corresponding parts are given the same reference numbers, and the description thereof will not be repeated.

<Film formation device>
FIG. 1 is a diagram showing an outline of a connection state by piping in one embodiment of the film forming apparatus of the present disclosure. According to the deposition apparatus of the present disclosure, the ruthenium-containing film and a platinum group metal-containing film osmium-containing film or the like can be deposited, as an example, the Ru 3 _{(CO) 12} gas as a ruthenium source gas used , an example of using a ClF ₃ gas as a cleaning gas fluorine containing.

The film forming apparatus 1 is a film forming apparatus for forming a ruthenium-containing film by a CVD method. With reference to FIG. 1, the film forming apparatus 1 discharges the raw material gas and the cleaning gas from the film forming chamber 10, the gas supply mechanism 20 for supplying the raw material gas and the cleaning gas to the film forming chamber 10, and the film forming chamber 10. The gas discharge mechanism 50 is provided. With reference to FIG. 2, the film forming chamber 10, the gas supply mechanism 20, and the gas discharge mechanism 50 are controlled by the control unit 100.

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 a CVD method. The film forming chamber 10 includes a gate (not shown) for carrying in and out the substrate to be processed, and a heater (not shown) for bringing the inside of the chamber to a predetermined temperature.

With reference to FIG. 1, the film forming chamber 10 is connected to the gas supply mechanism 20 via the first supply pipe 91 and the 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 a 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.

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, but the first supply pipe 91 and the second supply pipe are connected separately. It is also possible to combine the 92 with the film forming chamber 10 upstream of the film forming chamber 10 so that the film forming chamber 10 is provided with one gas supply port. When the first supply pipe 91 and the second supply pipe 92 are merged upstream of the film forming chamber 10, valves are provided in each of the first supply pipe 91 and the second supply pipe 92, and the first supply pipe 91 and the second supply pipe 92 are provided with valves. It is possible to switch whether to supply gas from the first supply pipe 91 or the second supply pipe 92.

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 step.

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, but the gas discharge port of the film forming chamber 10 is provided at one place. The first exhaust pipe 75 and the second exhaust pipe 76 may be branched downstream thereof.

The gas supply mechanism 20 will be described.
The gas supply mechanism 20 is a mechanism for supplying the raw material gas for forming a ruthenium-containing film by the CVD method and the 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 for accommodating _{Ru 3} (CO) ₁₂ as a solid film forming raw material P. A heater 46 is provided around the film-forming raw material container 45. _{The Ru 3} (CO) ₁₂ housed in the film-forming raw material container 45 is heated by the heater 46 and vaporized to become the Ru ₃ (CO) ₁₂ 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. The carrier gas supply pipe 25 is provided with a mass flow controller 31 for flow rate control and valves 44a and 44b before and after the mass flow controller 31. Further, the raw material gas supply pipe 26 is provided _{with a flow meter 35 for grasping the amount of Ru 3} (CO) ₁₂ gas and a valve 44c whose opening and closing can be adjusted based on the measured value of the flow meter 35. ..

The gas supply mechanism 20 has an additional gas supply source 23 for supplying Ar, which is a diluted gas, and an additional gas supply pipe 27. The additional gas supply pipe 27 connects the additional gas supply source 23 with the raw material gas supply pipe 26 and the first supply pipe 91. On the side of the additional gas supply source 23 of the additional gas supply pipe 27, a mass flow controller 32 for flow rate control and valves 43a and 43b before and after the mass flow controller 32 are provided.

_{With the above configuration, the raw material gas containing Ru 3} (CO) ₁₂ supplied from the film forming raw material container 45 is conveyed to the CO gas, which is a carrier gas, and mixed with the Ar gas to form the first supply pipe 91. Through it, it can be supplied into the film forming chamber 10. The carrier gas supply pipe 25 may be branched and the CO gas may be introduced into the film forming chamber 10 separately from the raw material gas as a counter gas.

The cleaning gas supply pipe 28 having a cleaning gas supply source 22 and a cleaning gas supply pipe 28 for supplying _{ClF 3} gas used as a cleaning gas is a cleaning gas supply source 22. , The carrier gas supply pipe 29 and the second supply pipe 92 are connected. On the cleaning gas supply source 22 side of the cleaning gas supply pipe 28, a mass flow controller 33 for flow rate control and valves 42a and 42b before and after the mass flow controller 33 are provided.

_{The ClF 3} gas, which is a cleaning gas, is conveyed by an 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. On the carrier gas supply source 21 side of the carrier gas supply pipe 29, a mass flow controller 34 for flow rate control and valves 41a and 41b before and after the mass flow controller 34 are provided.

_{With the above configuration, the ClF 3} gas supplied from the cleaning gas supply source 22 can be carried by the Ar gas and supplied into the film forming chamber 10 via the second supply pipe 92.

The gas discharge mechanism 50 will be described.
The gas discharge mechanism 50 is a mechanism for discharging the raw material gas after being subjected to 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. Further, instead of using the refrigerant, a vacuum cold trap provided with a cooling surface can be used as the first capture device 51.

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

The abatement device 80 is connected to the dry pump 61 via a pipe. The abatement device 80 removes the CO gas and the raw material gas containing ruthenium that could not be captured by the first capture device 51. A specific embodiment of the abatement device 80 is, for example, a combustion type abatement device. The CO gas conveyed to the abatement device 80 is incinerated in the abatement device 80 and discharged into the atmosphere as _{CO 2 gas.} As the abatement device, in addition to the combustion type abatement device, a heating type aggression device such as a plasma type aggression device and a heater type aggression device can be used.

Although the first exhaust pipe 75 is connected to the first capture device 51 in the embodiment of FIG. 1, an auxiliary capture device may be provided in the middle of the first exhaust pipe 75. Further, a dry pump may be arranged upstream of the first capture device 51 so that the first capture device 51 is under atmospheric pressure.

The gas discharge mechanism 50 includes a second capture device 52 connected to the film forming chamber 10 by the second exhaust pipe 76. The second scavenger 52 is a dry abatement device that holds the solid-grained scavenger 53 in, for example, a stainless steel container. The scavenger 53 is a scavenger capable of capturing ruthenium contained in the cleaning gas discharged from the film forming chamber 10 when the film forming chamber 10 is cleaned.

The scavenger 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 scavenger 53, ruthenium (ruthenium fluoride) fluorinated by the fluorine-based cleaning gas contained in the cleaning gas can be captured as ruthenium oxide. In addition, it is possible to eliminate _{ClF 3 with the scavenger 53.}

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 the flange 54a and is inserted into the scavenger 53. The second capture device 52 includes an outlet pipe 78. The outlet pipe 78 discharges the detoxified gas that has passed through the scavenger 53. The outlet pipe 78 is provided with a flange 54b. At the positions of the flanges 54a, 54b, the second capture device 52 is removable from the second exhaust pipe 76. Since the second scavenger 52 is removable from the second exhaust pipe 76, the removal of ruthenium from the scavenger 53 can be carried out with the second scavenger 52 separated from the film forming apparatus 1. That is, the separation and purification of ruthenium from the scavenger 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.

In the embodiment of FIG. 1, when the second capture device 52 has a function of not only capturing ruthenium but also abatement of a fluorine compound, the second capture device 52 does not need to be connected to the abatement device 80 and is expensive. There is no need to use stainless steel piping. As a result, since the fluorine compound is not mixed into the abatement device 80, corrosion does not occur and the maintenance frequency can be reduced.

Next, the control connection of the embodiment shown in FIG. 1 will be described with reference to FIGS. 1 and 2.
With reference 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.

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 to the abatement apparatus via the film forming chamber. The control unit 100 controls the open / closed states of the plurality of valves 41a to 44a, 41b to 44b, and 44c included in the gas supply mechanism 20 to control the types and mixing of the raw material gas and the cleaning gas supplied from the gas supply mechanism 20. Adjust the rate and flow rate. Further, the control unit 100 receives the measured value signal of the flow meter 35 and adjusts the open / closed 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.

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

The control unit 100 also controls the open / closed state 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 and 62 included in the gas discharge mechanism 50. By adjusting the outputs of the pumps 61 and 62, the control unit 100 adjusts and maintains the pressure in the film forming chamber 10 and the piping connected to the film forming chamber 10 to a predetermined value. By controlling the outputs of the pumps 61 and 62, the flow rate and pressure of the raw material gas and cleaning gas supplied to the film forming chamber 10, the raw material gas after film forming and the cleaning gas after cleaning discharged from the film forming chamber 10 Flow rate and pressure are adjusted.

<Material used for film formation method>
<Material used for film formation>
The metal film formed in the film forming apparatus of the present disclosure 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.

When forming a ruthenium-containing film, various organic and inorganic ruthenium raw material gases can be used as the ruthenium raw material gas. For example, ruthenium carbonyl (Ru ₃ (CO) ₁₂ ) can be suitably used. Ru ₃ (CO) ₁₂ gas becomes Ru by thermal decomposition. At this time, it is preferable to use CO gas as the carrier gas of _{Ru 3} (CO) _{12 gas.} By using CO as the carrier gas, the decomposition reaction _{of Ru 3} (CO) _{12 gas in the processing container can be suppressed, and the structure of Ru 3} (CO) ₁₂ is supplied to the substrate to be processed while maintaining the structure as much as possible. Can form a film. A ruthenium-containing film other than the ruthenium film may be formed by reacting the Ru ₃ (CO) _{12 gas with the reaction gas.}

As ruthenium raw material gas, in addition to Ru ₃ (CO) ₁₂ , RuO ₂ , Ru (EtCp) ₂ , Ru (DMDB) (CO) ₃ , RuO ₄ (HFE), Ru (HDAC), Ru (PF ₃ ), Ru (AMD) ₂ CO, RuCOT and the like can be mentioned, and at least one of these raw materials including _{Ru 3} (CO) _{12 can be used.}

The reaction gas for forming a ruthenium-containing film other than the ruthenium film is appropriately selected depending on the ruthenium raw material gas and the ruthenium-containing film to be obtained. Examples of the reaction gas include CO ₂ , O ₂ , H ₂ , Si H ₄ , Si _{2 H 6} , Si ₃ H ₈ , Si ₄ H ₁₀ , NH ₃ , CH ₃ (NH) NH ₂ , C ₂ H ₈ N. ₂ , N ₂ H _4, etc. can be mentioned, and at least one of these can be used.

_{When CO 2} , O ₂ , or H ₂ is used as the reaction gas, a ruthenium film or a ruthenium oxide film can be formed. _{When SiH 4} , Si ₂ H ₆ , Si ₃ H ₈ , or Si ₄ H ₁₀ is used as the reaction gas, a ruthenium film containing Si can be formed. _{When NH 3} , CH ₃ (NH) NH ₂ , C ₂ H ₈ N ₂ , and N ₂ H ₄ are used as the reaction gas, a ruthenium film containing N can be formed. It is also possible to form a doped ruthenium film using a gas containing a dopant.

When forming a ruthenium simple substance film, no reaction gas is used. As a carrier gas for diluting and transporting the raw material gas in the case of forming a ruthenium single film, it is possible to use an inert gas such as N ₂ gas or a rare gas. Examples of the rare gas include Ar, He, Ne, Xe, Kr and the like.

<Material used for cleaning>
In the recovery method and the manufacturing method of the present disclosure, a cleaning gas containing fluorine is used as the cleaning gas. _{ClF 3} can be preferably used as the cleaning gas containing fluorine. Examples of the cleaning gas other than _{ClF 3 include F 2} , F ₂ / N _{2 mixed gas, NF 3} , CF ₄ , C ₂ F ₆ , C ₃ F ₈ , SF ₆ excited in a plasma state, and the like. These fluorine-containing cleaning gases may be used alone or in combination of two or more.

In cleaning, a carrier gas that carries the above-mentioned cleaning gas may be used. The carrier gas may be an inert gas such as N ₂ gas or a rare gas. Examples of the rare gas include Ar, He, Ne, Xe, Kr and the like.

<Film formation method>
A method for producing a ruthenium-containing film according to an embodiment of the present disclosure will be described with reference to FIGS. 1 to 3.
FIG. 3 is a flowchart showing a method for producing 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 for forming a ruthenium-containing film on a substrate, a step S20 for taking out the substrate from the film forming chamber, and introducing a cleaning gas into the film forming chamber. It has a step S30 and a step S40 for introducing the cleaning gas into the trapping container.

The step S10 for forming a ruthenium-containing film on the substrate will be described. In the film forming step S10, the following operation is executed by the control unit 100.

In the film forming step S10, the substrate is conveyed 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 operate the film forming chamber 10. The inside is set 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 in 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.

At the same time 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 (Ru 3} (CO) _12). Further, the valves 44a and 44b are opened, and CO gas is blown into the film forming raw material container 45 via the carrier gas supply pipe 25. _{The Ru 3} (CO) ₁₂ gas in the film forming raw material container 45 is supplied into the film forming chamber 10 via the raw material gas supply pipe 26 and the first supply pipe 91 in a state of being carrierd by the CO gas. The flow rate of the Ru ₃ (CO) ₁₂ gas is measured by the flow meter 35, and the control unit 100 can change the open / closed state of the valve 44c according to the measured value. Further, the control unit 100 can adjust the open / closed state of the valves 43a and 43b and supply the added gas (diluted gas) from the added gas supply source 23. The flow rate of the raw material gas and the mixing ratio of the raw material gas and the diluted gas can be appropriately set according to the film thickness of the target ruthenium-containing film, the type of the substrate, and the like.

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 forming chamber 10.

In the film forming step S10, the valves 41a, 41b, 42a, 42b of the gas supply mechanism 20 are closed, and the gas from the second supply pipe 92 to the film forming chamber 10 is shut off.

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

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

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

In the film forming 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 forming step S10 is not discharged to the second exhaust pipe 92.

The step S20 for taking out the substrate from the film forming chamber will be described.
Following the film forming step S10, the substrate on which the ruthenium-containing film is formed on the surface is taken out from the film forming chamber 10. This step can be performed by a known method and is not particularly limited. For example, in the film forming step S10, the raw material gas is supplied into the film forming chamber 10 and a predetermined time (for example, 1 to 600 seconds) has elapsed. The substrate can be taken out from the film chamber 10 so that the substrate does not exist in the film forming chamber 10.

After repeating the film forming step S10 and the taking-out step S20 once or a plurality of times, it is determined whether or not to clean the inside of the film forming chamber. Specifically, for example, it is determined whether or not the amount of ruthenium deposited in the film forming chamber 10 exceeds the allowable amount (Q10). The determination criterion may be, for example, the number of times the film formation is repeated (the number of film formations), or the elapsed time from the start of the film formation. When it is determined that the amount of ruthenium deposited in the film forming chamber 10 is within the allowable range (NO in Q10), the film forming step S10 and the taking-out step S20 are carried out again.

On the other hand, if it is determined that the amount of ruthenium deposited in the film forming chamber 10 exceeds the allowable range (YES in Q10), a method of recovering ruthenium existing in the film forming chamber is implemented. Specifically, the step S30 for introducing the cleaning gas into the film forming chamber and the step S40 for introducing the cleaning gas into the trapping container are carried out.

The cleaning gas introduction step S30 is carried out in a state where the substrate does not exist in the film forming chamber 10 after the step S20 of taking out the substrate from the film forming chamber. The inside of the film forming chamber 10 is heated to a predetermined temperature, for example, 150 to 250 ° C. by the heater of the film forming chamber 10.

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 forming chamber 10 is shut off.

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 if the cleaning gas is introduced into the first trapping device 51 in which ruthenium or the like is captured, it is avoided to introduce the cleaning gas into the first exhaust pipe 75.

In the cleaning gas introduction step S30, the dry pump 62 operates, first opens the valves 41a and 41b, supplies carrier gas (for example, Ar gas) from the carrier gas supply source 21, and purges the inside of the film forming chamber 10. The pressure in the film forming chamber 10 is adjusted to, for example, 10 to 1000 Pa. _{In this state, ClF 3} , which is a cleaning gas, is introduced into the film forming chamber 10 and dry cleaning is performed.

Although not particularly bound by theory, it is considered that the following chemical reaction occurs in dry cleaning, and ruthenium existing in the film forming chamber 10 is discharged as ruthenium pentafluoride gas.
Ru + 5 / 3ClF ₃ → RuF ₅ ↑ + 5 / 6Cl ₂ ↑

In the dry cleaning, the valves 41a and 41b are opened and Ar gas, which is a carrier gas, is flowed, and the valves 42a and 42b are further opened to supply _{ClF 3 gas.} The ClF ₃ gas flow rate can be appropriately set according to the internal volume of the film forming chamber, the film thickness of the ruthenium film accumulated in the film forming chamber, and the like. The supply time of ClF ₃ gas is preferably in the range of 1 to 60 sec, and the number of repetitions is preferably about 1 to 100 times.

Following the cleaning gas introduction step S30, or at the same time as the cleaning gas introduction step S30, the valves 73, 79a, 79b are opened, and the cleaning gas is introduced into the second capture device 52 (S40). The second capture device 52 is provided downstream of the dry pump 62, i.e., 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 comes into contact with the capture agent 53.

The cleaning gas introduced into the scavenger 53 contains ClF ₃ and RuF ₅ (ruthenium fluoride). The scavenger 53 is at least one selected from the group consisting of soda lime, slaked lime and CaO (calcium oxide), and the scavenger eliminates the cleaning gas by capturing _{ClF 3 and ruthenium fluoride.}

Soda lime is also called soda lime, and is a strong basic solid granular substance containing calcium hydroxide as a main component and 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.

Although not particularly bound by theory, it is believed that contact between ruthenium fluoride and a scavenger causes the following chemical reaction, which turns ruthenium fluoride into ruthenium oxide and is immobilized on the scavenger. ..
Ca (OH) ₂ + RuF ₅ → CaF ₂ + RuO ₂ + CaCl ₂

The cleaning gas detoxified by the second capture device 52 is released into the atmosphere through the exhaust pipe 78 of the second capture device 52.

After repeating the cleaning gas introduction step S30 into the film forming chamber 10 and the cleaning gas introduction step S40 into the second capture device 52 once or a plurality of times, it is determined whether to replace the capture device. Specifically, it is determined whether or not the replacement time of the capture container 52 has been reached (Q20). The determination criterion may be, for example, the number of repetitions of dry cleaning, or the elapsed time from the start of use of the capture device. Further, the replacement time can be determined based on the detection signal from the gas detector (for example, Cl _{2 sensor) provided in the second capture device 52.} If it is determined that the container replacement time has not been reached (NO in Q20), the cleaning gas introduction step S30 to the film forming chamber 10 and the cleaning gas introduction step S40 to the second capture device 52 are performed again. ..

On the other hand, when it is determined that the container replacement time has been reached (YES in Q20), the valves 79a and 79b are closed, the piping is cut off at the flanges 54a and 54b, and the second capture device 52 is seconded. Removed from the exhaust pipe 76 (S50). It is preferable that the second capture device 52 is provided with casters or the like so that the removed capture device can be easily moved.

After removing the second capture device 52 from the second exhaust pipe 76, ruthenium is taken out from the capture agent 53 contained in the second capture device 52 (S60). The ruthenium extraction step S60 can be performed independently of the production of the ruthenium film at a location different from the installation location of the film forming apparatus.

Specifically, the ruthenium extraction step S60 can be carried out by introducing a strong acid such as hydrochloric acid or sulfuric acid into the scavenger 53 and allowing ruthenium oxide immobilized on the scavenger to flow out as an aqueous solution of ruthenium chloride.

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

<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 will be omitted.

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 will be omitted.

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 the flange 540a and is inserted into the scavenger 530. The second capture device 520 includes an outlet pipe 780. The outlet pipe 780 discharges the detoxified gas that has passed through the scavenger 530. The outlet pipe 780 is provided with a flange 540b. At the flange 540a, the second capture device 520 is removable from the second exhaust pipe 76. A pipe 731 is connected to the downstream of the flange 540b. That is, the second capture device 520 is removable from the second exhaust pipe 76 and the pipe 731 at the positions of the flanges 540a and 540b.

The second capture device 520 is connected to the dry pump 620 via the pipe 731. That is, when the dry pump 620 is operated to perform dry cleaning, the second capture device 520 becomes a decompressed atmosphere. The downstream of the dry pump 620 is connected to the abatement device 800, and the gas discharged from the dry pump 620 is detoxified by the abatement device 800 and released into the atmosphere.

In the embodiment of FIG. 4, since the second capture device 520 is connected to the abatement device 800, the abatement function of the fluorine compound is unnecessary and only ruthenium capture is sufficient. In this case, since the alkaline chemical in the second capture device 520 reacts with the fluorine compound, it is possible to suppress the corrosion of the abatement device 800 by reducing the amount of the fluorine compound mixed in the abatement device 800. can. It was

<Example>
Hereinafter, examples will be described.
Using the film forming apparatus shown in FIG. 1, a _{ruthenium film was formed with Ru 3} (CO) ₁₂ gas and CO gas by the above-mentioned film forming method. The ruthenium film deposited on the wall of the film forming chamber was dry-cleaned using _{ClF 3 as a cleaning gas.} In this embodiment, the _{cleaning with ClF 3} is performed for each film forming process, but the cleaning may be determined based on the thickness of the ruthenium film deposited on the wall of the film forming chamber. During dry cleaning, ruthenium was captured using a trapping device that contained soda lime in a stainless steel outer cylinder container.

After performing dry cleaning, the scavenger was removed from the exhaust pipe of the cleaning gas, and the appearance of the scavenger inside the scavenger was observed. The scavenger turned dark brown, confirming that ruthenium pentafluoride was immobilized. Hydrochloric acid was injected into the scavenger to recover ruthenium as an aqueous solution of ruthenium chloride.

It was calculated that the ruthenium recovered by dry cleaning was about 10% of the ruthenium raw material used for film formation. Since the ruthenium removed by dry cleaning was not recovered by the conventional film forming method, it was confirmed that the recovery efficiency of ruthenium was improved by about 10% in this example as compared with the conventional method. ..

It should be understood that the embodiments disclosed this time are exemplary in all respects and are not restrictive in any respect. The scope of the present invention is defined by the scope of claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims.

The platinum group metal recovery method, the platinum group metal-containing film manufacturing method, and the film forming apparatus of the present disclosure can be particularly advantageously applied in semiconductor manufacturing by the CVD method.

1,100 Formation device 10 Formation 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 Raw material gas supply pipe 27 Additional gas supply pipe 28 Cleaning gas supply piping 29 Carrier gas supply piping 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 formation 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 Piping 75, 76 Exhaust piping 77, 770 Cleaning gas introduction Piping 78, 780 Exhaust piping 80, 800 Abatement device 91, 92 Supply piping

Claims (11)

1. After introducing a raw material gas containing a platinum group metal into the film forming chamber and forming a platinum group metal-containing film on the surface of the substrate housed in the film forming chamber, the platinum group existing in the film forming chamber is formed. It ’s a way to recover metal,
   (I) A step of introducing a cleaning gas containing fluorine into the film forming chamber from which the substrate is taken out, and
   (Ii) A step of introducing the cleaning gas discharged from the film forming chamber into a trapping container holding a trapping agent consisting of at least one selected from the group consisting of soda lime, slaked lime and CaO. , Platinum group metal recovery method.
2. The method for recovering a platinum group metal according to claim 1, wherein the scavenger is soda lime.
3. The method for recovering a platinum group metal according to claim 1 or 2, wherein the platinum group metal is ruthenium or osmium.
4. The method for recovering a platinum group metal according to any one of claims 1 to ₃ , wherein the cleaning gas is ClF 3.
5. After (i) the step of introducing the cleaning gas into the film forming chamber and (ii) the step of introducing the cleaning gas discharged from the film forming chamber into the trapping container.
   (Iii) The method for recovering a platinum group metal according to any one of claims 1 to 4, further comprising a step of extracting the platinum group metal from the scavenger.
6. (Iii) In the step of taking out the platinum group metal from the scavenger, the platinum group metal foot adsorbed by the scavenger is introduced by introducing a strong acid into the scavenger after removing the trapping container from the film forming apparatus. Including the step of taking out the compound as a platinum group metal salt solution,
   The method for recovering a platinum group metal according to claim 5.
7. (I) A step of introducing a raw material 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 housed in the film forming chamber.
   (II) A step of taking out the substrate on which the platinum group metal-containing film is formed from the film forming chamber, and
   (III) A step of recovering the platinum group metal existing in the film forming chamber is provided.
   The step of recovering the platinum group metal existing in the film forming chamber (III) is carried out by the method for recovering the platinum group metal according to any one of claims 1 to 6.
   A method for producing a platinum group metal-containing film.
8. (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 were repeated a plurality of times in this order.
   After that,
   (III) A step of recovering the platinum group metal existing in the film forming chamber is carried out.
   The method for producing a platinum group metal-containing film according to claim 7.
9. A film formation chamber for forming a thin film on the surface of the substrate,
   A gas supply mechanism connected to the film forming chamber and
   A gas discharge mechanism connected to the film forming chamber and
   The film forming chamber, the gas supply mechanism, and a control unit for controlling the gas discharge mechanism are provided.
   The gas supply mechanism is
   The first supply pipe for supplying the raw material 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 is provided.
   The gas discharge mechanism is
   A first exhaust pipe connecting the film forming chamber and a first capturing device capable of capturing the platinum group metal contained in the raw material gas discharged from the film forming chamber.
   A second exhaust pipe connecting the film forming chamber and a second capturing device holding a scavenger capable of capturing the platinum group metal contained in the cleaning gas discharged from the film forming chamber. Equipped with
   Film forming equipment.
10. The film forming apparatus according to claim 9, wherein the scavenger is at least one selected from the group consisting of soda lime, slaked lime and CaO.
11. The film forming apparatus according to claim 9, wherein the second capture device is removable from the second exhaust pipe.

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