JP2013199673A - Method for forming ruthenium oxide film and method for cleaning treatment container for forming ruthenium oxide film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming a ruthenium oxide film, capable of cleaning an inside of a treatment container at low cost in a short time, and to provide a method for cleaning the treatment container for forming the ruthenium oxide film.SOLUTION: A method for forming a ruthenium oxide film includes: a step of storing a substrate in a treatment container, feeding a gas-phase ruthenium compound on the substrate, and feeding an oxygen gas on the substrate to form the ruthenium oxide film on the substrate by a reaction of the gas of ruthenium compound with the oxygen gas; a step of conveying out the substrate from the treatment container and introducing a hydrogen gas into the treatment container so that the inside of the treatment container is subjected to hydrogen annealing; and a step of introducing at least one of a CIFgas, an Fgas and an HF gas as a cleaning gas into the treatment container after the hydrogen annealing to clean the inside of the treatment container.

Description

  The present invention relates to a ruthenium oxide film forming method for forming a ruthenium oxide film by a chemical vapor deposition method (CVD method) and a ruthenium oxide film forming processing container cleaning method.

  Recently, various high dielectric constant materials (High-k materials) have been used as materials for capacitors of DRAMs, and ruthenium oxide films (RuOx films) as electrode materials for capacitors using such High-k material films. Is attracting attention.

  The capacitor electrode is required to be able to form a film in a recess having a high aspect ratio, and good step coverage is required. For this reason, formation of a RuOx film by a CVD method with essentially good step coverage has been studied (for example, Patent Document 1). In addition, the formation of a RuOx film by an ALD (Atomic Layer Deposition) method that alternately supplies a precursor and a reducing gas, which is a kind of CVD method, is also being studied.

  By the way, when a RuOx film is formed by the CVD method (including the ALD method), the reaction product (mainly RuOx) adheres to the inner wall of the chamber, which is a processing container, and therefore the chamber is cleaned at a predetermined timing. There is a need to. As a technique for cleaning the chamber after forming the RuOx film, a technique using ozone is known (for example, Patent Document 2).

JP-A-6-283438 JP 2001-284317 A

However, cleaning using ozone requires an ozonizer for each film forming apparatus, which increases the cost. Further, if ClF ₃ gas or F ₂ gas used in a general CVD chamber can be used as a cleaning gas, cleaning can be performed at low cost, but ClF ₃ gas or F ₂ gas has a low etching rate, There is a problem that cleaning takes time.

  The present invention has been made in view of such circumstances, and a method for forming a ruthenium oxide film and a cleaning container for forming a ruthenium oxide film capable of cleaning the inside of the processing container at a low cost and in a short time. It is an object to provide a method.

In order to solve the above problems, the present invention accommodates a substrate in a processing container, supplies a ruthenium compound on the substrate in a gas phase state, and supplies oxygen gas onto the substrate. A step of forming a ruthenium oxide film on the substrate by reaction with oxygen gas, a step of unloading the substrate from the processing vessel, introducing hydrogen gas into the processing vessel, and subjecting the processing vessel to hydrogen annealing; And a step of cleaning the inside of the processing vessel by introducing at least one of ClF ₃ gas, F ₂ gas, and HF gas as a cleaning gas into the processing vessel after the hydrogen annealing. A ruthenium oxide film forming method is provided.

The present invention also includes a substrate contained in a processing vessel, a ruthenium compound is supplied onto the substrate in a gas phase state, and an oxygen gas is supplied onto the substrate to react the ruthenium compound gas with the oxygen gas. A ruthenium oxide film deposition processing container cleaning method for performing a film deposition process for depositing a ruthenium oxide film on a substrate and then cleaning the process container, wherein after the film deposition process, the process container In the state where the substrate does not exist, hydrogen gas is introduced into the processing container to anneal the inside of the processing container, and then ClF ₃ gas, F ₂ gas, and HF gas are used as cleaning gases in the processing container. A method for cleaning a processing container for forming a ruthenium oxide film is provided, wherein one or more of these are introduced to clean the inside of the processing container.

  Furthermore, the present invention is a storage medium that operates on a computer and stores a program for controlling a film forming apparatus, and the program executes the ruthenium oxide film forming method when executed. A storage medium is provided that causes a computer to control the film formation apparatus.

In the present invention, the ruthenium compound has a structure of the following formula (1) in which two β-diketones and two groups selected from orphene, amine, nitrile, and carbonyl are coordinated to Ru. A thing can be used suitably.
However, R ₁ and R ₂ are alkyl groups having 2 to 5 total carbon atoms, and R ₃ is a group selected from an orphen group, an amine group, a nitrile group, and a carbonyl group.

  In the present invention, the hydrogen annealing step is preferably performed at a temperature in the processing container of 120 to 300 ° C., and the cleaning step is performed at a temperature in the processing container of 180 to 300 ° C. It is preferable to be performed.

  Furthermore, in the present invention, the reaction product mainly composed of ruthenium oxide produced in the processing vessel may be reduced by the hydrogen annealing to be a reduction product mainly composed of ruthenium metal. .

  In this specification, the unit of the gas flow rate is mL / min. However, since the volume of the gas varies greatly depending on the temperature and the atmospheric pressure, the value converted into the standard state is used in the present invention. In addition, since the flow volume converted into the standard state is normally indicated by sccm (Standard Cubic Centimeter per Minutes), sccm is also written together. The standard state here is a state (STP) at a temperature of 0 ° C. (273.15 K) and an atmospheric pressure of 1 atm (101325 Pa).

According to the present invention, a reaction product mainly composed of ruthenium oxide is reduced mainly to a metal ruthenium film by hydrogen annealing after the ruthenium oxide film is formed by the CVD method. Therefore, ClF ₃ gas, F ₂ gas In addition, the etching rate with one or more cleaning gases of HF gas can be increased, and the inside of the processing container can be cleaned in a short time. In addition, ClF ₃ gas or the like used as a cleaning gas can be cleaned by simply introducing it into a heated processing container, so that additional equipment such as an ozonizer is not required and the cost is low.

It is a schematic diagram which shows an example of the film-forming apparatus for enforcing the film-forming method of the ruthenium oxide film which concerns on one Embodiment of this invention. It is a flowchart which shows the film-forming method of the ruthenium oxide film | membrane which concerns on one Embodiment of this invention. It is a timing chart which shows the film-forming sequence at the time of forming into a film by ALD method. 200 ° C., 250 ° C., at 300 ° C., is a diagram showing an etching rate when etching the RuO ₂ film and Ru film ClF _3. With the RuO ₂ film formed on the evaluation substrate (as depo.) And after the film formation, the surface condition of the evaluation substrate when hydrogen annealing was performed by changing the temperature to 120 ° C., 150 ° C., and 200 ° C. FIG. On the evaluation substrate which is a diagram showing an X-ray diffraction pattern in the case of performing the case and 226 ° C. were performed at 120 ° C. The hydrogen annealing after forming the RuO ₂ film.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a schematic view showing an example of a film forming apparatus for carrying out a method for forming a ruthenium oxide film according to an embodiment of the present invention.

  This film forming apparatus 100 has a substantially cylindrical chamber 1 that is airtightly configured, and in this, a semiconductor wafer W (hereinafter referred to as a wafer) that is a substrate to be processed is horizontally supported. The susceptor 2 is arranged in a state of being supported by a cylindrical support member 3 that reaches the lower center of the exhaust chamber, which will be described later. The susceptor 2 is made of a ceramic such as AlN. Further, a heater 5 is embedded in the susceptor 2, and a heater power source 6 is connected to the heater 5. On the other hand, a thermocouple 7 is provided in the vicinity of the upper surface of the susceptor 2, and a signal of the thermocouple 7 is transmitted to the heater controller 8. The heater controller 8 transmits a command to the heater power supply 6 in accordance with a signal from the thermocouple 7, and controls the heating of the heater 5 to control the wafer W to a predetermined temperature. The susceptor 2 is provided with three wafer raising / lowering pins (not shown) so as to be able to project and retract with respect to the surface of the susceptor 2, and is projected from the surface of the susceptor 2 when the wafer W is transferred. To be.

A circular hole 1 b is formed in the top wall 1 a of the chamber 1, and a shower head 10 is fitted so as to protrude into the chamber 1 therefrom. The shower head 10 is for discharging a film forming gas supplied from a gas supply mechanism 30 described later into the chamber 1, and a film forming material gas and a cleaning gas are introduced into the upper part thereof. 1 introduction path 11 and a second introduction path 12 for introducing oxygen gas (O ₂ gas), dilution gas (Ar gas is exemplified) and hydrogen gas (H ₂ gas) as a reducing gas into the chamber 1. Have.

  Inside the shower head 10, spaces 13 and 14 are provided in two upper and lower stages. A first introduction path 11 is connected to the upper space 13, and a first gas discharge path 15 extends from the space 13 to the bottom surface of the shower head 10. A second introduction path 12 is connected to the lower space 14, and a second gas discharge path 16 extends from the space 14 to the bottom surface of the shower head 10. That is, the shower head 10 discharges the film forming source gas and the oxygen gas independently from the gas discharge paths 15 and 16.

  An exhaust chamber 21 that protrudes downward is provided on the bottom wall of the chamber 1. An exhaust pipe 22 is connected to the side surface of the exhaust chamber 21, and an exhaust device 23 having a vacuum pump, a pressure control valve, and the like is connected to the exhaust pipe 22. The inside of the chamber 1 can be brought into a predetermined reduced pressure state by controlling the opening degree of a pressure control valve (not shown) that operates the exhaust device 23.

  On the side wall of the chamber 1, a loading / unloading port 24 for loading / unloading the wafer W and a gate valve 25 for opening / closing the loading / unloading port 24 are provided. A heater 26 is provided on the wall portion of the chamber 1 so that the temperature of the inner wall of the chamber 1 can be controlled during the film forming process.

The gas supply mechanism 30 includes a raw material gas delivery pipe 36 connected to the first introduction path 11 of the shower head 10 and a gas supply pipe 40 connected to the second introduction path 12. A film forming raw material tank 31 for storing a ruthenium compound as a film forming raw material (precursor) for supplying a raw material gas through the raw material gas delivery pipe 36 and a gas containing fluorine as a cleaning gas through the raw material gas delivery pipe 36 It has a ClF ₃ gas supply source 53 for supplying a certain ClF ₃ gas, and further supplies an O ₂ gas supply source 42 for supplying O ₂ gas as a reducing gas via the gas supply pipe 40, and a gas supply pipe 40. via has a H ₂ gas supply source 44 for supplying H ₂ gas through the Ar gas supply source 43, and the gas supply pipe 40 for supplying Ar gas as a diluent gas

  A heater 31a is provided around the film forming material tank 31 so that the film forming material in the film forming material tank 31 can be heated to an appropriate temperature.

  A bubbling pipe 32 for supplying Ar gas as a bubbling gas from above is inserted into the film forming material tank 31 so as to be immersed in the film forming material. An Ar gas supply source 33 is connected to the bubbling pipe 32, and a mass flow controller 34 as a flow rate controller and front and rear valves 35 are interposed. In addition, a raw material gas delivery pipe 36 is inserted into the film forming raw material tank 31 from above. A valve 37 is interposed in the source gas delivery pipe 36. The source gas delivery pipe 36 is provided with a heater 38 for preventing condensation of the film forming source gas. Then, Ar gas that is a bubbling gas is supplied to the film forming raw material in the film forming raw material tank 31, whereby the film forming raw material is vaporized by bubbling in the film forming raw material tank 31, and the generated film forming raw material gas is It is supplied into the shower head 10 through the raw material gas delivery pipe 36 and the first introduction path 11.

  The bubbling pipe 32 and the source gas delivery pipe 36 are connected by a bypass pipe 51, and a valve 52 is interposed in the pipe 51. Valves 35a and 37a are interposed on the downstream side of the pipe 51 connecting portion in the bubbling pipe 32 and the source gas delivery pipe 36, respectively. Then, by closing the valves 35a and 37a and opening the valve 52, Ar gas from the Ar gas supply source 33 passes through the bubbling pipe 32, the bypass pipe 51, and the source gas delivery pipe 36 into the chamber 1 as purge gas or the like. It is possible to supply.

As the bubbling gas or purge gas, other inert gas such as N ₂ gas can be used instead of Ar gas.

A valve 41 is provided in the gas supply pipe 40 connected to the second introduction path 12. The gas supply pipe 40 is branched into branch pipes 40a, 40b, and 40c. The O ₂ gas supply source 42 is connected to the branch pipe 40a, and the Ar gas supply source 43 is connected to the branch pipe 40b. The H ₂ gas supply source 44 is connected to the branch pipe 40c. The branch pipe 40a is provided with a mass flow controller 45 as a flow rate controller and its front and rear valves 46, and the branch pipe 40b is provided with a mass flow controller 47 as a flow rate controller and its front and rear valves 48. The branch pipe 40c is provided with a mass flow controller 49 as a flow rate controller and valves 50 before and after the mass flow controller 49. As the dilution gas and purge gas, other inert gas such as N ₂ gas can be used instead of Ar gas.

The ClF ₃ gas supply source 53 is connected to a cleaning gas supply pipe 54 leading to the raw material gas delivery pipe 36. The cleaning gas supply pipe 54 is provided with a mass flow controller 55 as a flow rate controller and valves 56 before and after the mass flow controller 55. Has been. As the cleaning gas, other fluorine-containing gases such as F ₂ gas and HF gas can be used.

The ruthenium compound used as a film-forming raw material is not particularly limited, and those conventionally used can be used. From Ru, two β-diketones, and two, orphene, amine, nitrile, and carbonyl. A ruthenium compound having the structure of the following formula (1) in which the selected group is coordinated is preferable.
R ₁ and R ₂ are alkyl groups having 2 to 5 total carbon atoms, and R ₃ is a group selected from orphene, amine, nitrile, and carbonyl.

_{Alternatively,} it is also possible to use a _{Ru (CP) 2, Ru (} C 5 H 5) 2, Ru (EtCp) 2, Ru (C 5 H 4 -C 2 H 5) 2 and the like.

  The film forming apparatus includes a control unit 60 that controls each component, specifically, a valve, a power source, a heater, a pump, and the like. The control unit 60 includes a process controller 61 including a microprocessor (computer), a user interface 62, and a storage unit 63. Each component of the film forming apparatus 100 is electrically connected to the process controller 61 and controlled. The user interface 62 is connected to the process controller 61 and visualizes the operation status of each component of the film forming apparatus and a keyboard on which an operator inputs commands to manage each component of the film forming apparatus. It consists of a display that displays it. The storage unit 63 is also connected to the process controller 61, and the storage unit 63 corresponds to a control program for realizing various processes executed by the film forming apparatus 100 under the control of the process controller 61 and processing conditions. A control program for causing each component of the film forming apparatus 100 to execute a predetermined process, that is, a process recipe, various databases, and the like are stored. The processing recipe is stored in the storage medium 63 a in the storage unit 63. The storage medium 63a may be a fixed medium such as a hard disk or a portable medium such as a CDROM, DVD, or flash memory. Moreover, you may make it transmit a recipe suitably from another apparatus via a dedicated line, for example.

  Then, if necessary, a predetermined processing recipe is called from the storage unit 63 by an instruction from the user interface 62 and is executed by the process controller 61, so that the film forming apparatus 100 can control the process controller 61. Desired processing is performed.

  Next, a method for forming a ruthenium oxide film according to an embodiment of the present invention performed by the film forming apparatus 100 as described above will be described.

  FIG. 2 is a flowchart showing a ruthenium oxide film forming method according to this embodiment. In the present embodiment, as shown in FIG. 2, a film forming process (process 1), a hydrogen annealing process (process 2), and a cleaning process (process 3) are performed.

First, the film forming step of step 1 will be described.
The gate valve 25 is opened, and the wafer W is loaded into the chamber 1 through the loading / unloading port 24 by a transfer device (not shown) and placed on the susceptor 2.

Next, the inside of the chamber 1 is evacuated by the exhaust device 23 to bring the inside of the chamber 1 to a predetermined pressure, and the susceptor 2 is heated to a film forming temperature, preferably a predetermined temperature in the range of 200 to 350 ° C. Then, Ar gas is supplied at a predetermined flow rate as a carrier gas from the bubbling pipe 32 to the film forming raw material tank 31 heated to, for example, 80 to 200 ° C. by the heater 31a, and the ruthenium compound as the film forming raw material is vaporized by bubbling. Then, the gas is supplied into the chamber 1 through the source gas delivery pipe 36, the first introduction path 11, and the shower head 10. Further, O ₂ gas as a reducing gas is supplied from the O ₂ gas supply source 42 into the chamber 1 through the branch pipe 40 a, the gas supply pipe 40, the second introduction path 12, and the shower head 10.

By supplying ruthenium compound gas and O ₂ gas as a reducing gas into the chamber 1, they react on the surface of the wafer W heated by the susceptor 2, and a ruthenium oxide film (RuO _{x) is formed on the} wafer W by thermal CVD. Film) is formed.

  As described above, the ruthenium compound is not particularly limited, and a conventionally used ruthenium compound can be used, and Ru is composed of two β-diketones and two olphens, amines, nitriles, and carbonyls. A ruthenium compound having the structure of the above formula (1) in which a selected group is coordinated is preferable. This ruthenium compound is liquid at room temperature and has a relatively low vapor pressure, so that it is easy to supply a gas phase.

When a ruthenium oxide (RuO _x ) film is formed using the ruthenium compound having the structure of the above formula (1) and O ₂ gas, the O ₂ partial pressure or the O ₂ gas / Ru compound gas content in the chamber 1 is used. The pressure ratio may be adjusted, and the O ₂ partial pressure in the chamber 1 is preferably 5 Torr (665 Pa) or higher, or the O ₂ gas / Ru compound gas partial pressure ratio is preferably 20 or higher.

In the ruthenium compound having the structure of the above formula (1), groups (ligands) such as orphene, amine, nitrile, and carbonyl coordinated to Ru are unlikely to interfere with adsorption to the substrate, and are relatively eliminated. Since it is easy, Ru is easily adsorbed to the wafer W. Therefore, by using this ruthenium compound as a film forming raw material and forming a RuO _x film using O ₂ gas as a reducing gas, it is possible to form a film at a high film formation rate with a short incubation time. It is possible to achieve good step coverage capable of forming a film in a recess having a high aspect ratio. Further, the remaining β-diketone (diketonate ligand) is easily decomposed by the O ₂ gas, and a RuO _x film can be quickly formed on the wafer W, so that a high film formation rate can be obtained.

The ruthenium compound having the structure of the above formula (1) is used as a film forming raw material, and a RuO _x film is formed using O ₂ gas as a reducing gas. The pressure in the chamber 1 at this time is 5 to 100 Torr (665 to 13330 Pa). The carrier gas flow rate is preferably 100 to 500 mL / min (sccm) (corresponding to a ruthenium compound 0.5 to 14.6 mL / min (sccm)), and the O ₂ gas flow rate as the reducing gas is 25 to 500 mL / min. (Sccm) is preferred.

  In the ruthenium compound, β-diketones include 2,4-hexanedione, 5-methyl-2,4-hexanedione, 2,4-heptanedione, 5-methyl-2,4-heptanedione, 6-methyl. Either -2,4-heptanedione or 2,4-octanedione can be used.

In addition, in the ruthenium compound having the structure of the above formula (1), those having the following structure of the formula (2) in which R ₃ is carbonyl are preferable. The carbonyl having a small molecular weight hardly interferes with the adsorption to the wafer W, and is particularly easily desorbed in the R ₃ group, so that the adsorptivity to the wafer W is extremely high. For this reason, the effect which shortens incubation time and the effect which improves step coverage can be exhibited more effectively.

As such a Ru compound, for example, a compound having a structure of the following formula (3) whose composition formula is C ₁₆ H ₂₂ O ₆ Ru can be given as a suitable example.

In forming the RuO _x film, in addition to supplying the ruthenium compound gas and the O ₂ gas simultaneously as described above, the ruthenium compound gas and the reducing gas O ₂ gas are purged as shown in FIG. It is also possible to use an ALD-like method of alternately supplying with sandwiching. Ar gas from an Ar gas supply source 43 can be used for purging. Further, Ar gas can be supplied from the Ar gas supply source 33 through the bubbling pipe 32, the bypass pipe 51, and the raw material gas delivery pipe 36, or both of them can be used. By this ALD method, a RuO _x film with less impurities can be obtained at a low film formation temperature.

After forming the RuO _x film as described above, the supply of the Ru compound gas and the O ₂ gas is stopped, the vacuum pump of the exhaust device 23 is turned off, and the chamber 1 is supplied from the Ar gas supply sources 43 and 33. Ar gas is supplied into the chamber to purge the chamber 1. Then, after the purge process is completed, the gate valve 25 is opened, and the wafer W is unloaded through the loading / unloading port 24 by a transfer device (not shown). Thereby, the film forming process for one wafer W is completed.

After performing the film forming step of step 1 on a predetermined number of wafers, the hydrogen annealing step of step 2 is performed prior to the cleaning step of step 3.
In the hydrogen annealing process, the chamber 1 is heated to a predetermined temperature by the heater 5 while the wafer 1 is not present in the chamber 1, and the chamber 1 is set to a predetermined pressure, and the H ₂ gas supply source 44 supplies the inside of the chamber 1. H ₂ gas is introduced into the chamber 1 and hydrogen annealing in the chamber 1 is performed.

The temperature at this time is preferably 120 to 300 ° C. When the temperature of hydrogen annealing is lower than 120 ° C., RuO _x is not sufficiently reduced. The temperature of hydrogen annealing is preferably the same as the cleaning performed continuously. As a result, it is not necessary to change the temperature during cleaning, and the efficiency can be improved. The pressure in the chamber 1 is preferably 50 to 90 Torr (6665 to 11997 Pa), and the H ₂ gas flow rate is preferably 1000 to 5000 mL / min (sccm).

The reaction product mainly composed of ruthenium oxide (RuO _x ) adheres to the inner wall of the chamber 1 and the shower head 10 by the film formation, and this is removed by cleaning. In this embodiment, the cleaning gas Assuming that a fluorine-containing gas typified by ClF ₃ gas, which is generally used as a cleaning gas for a CVD chamber, is used. However, RuO _x, which is the main component of the reaction product, has a low reactivity with ClF ₃ gas, so the etching rate is low, and it takes a long time for cleaning, resulting in a decrease in throughput. In contrast, Ru was found to have a high reactivity with ClF ₃ gas and a high etching rate. FIG. 4 is a diagram showing an etching rate when the RuO ₂ film and the Ru film are etched with ClF ₃ at 200 ° C., 250 ° C., and 300 ° C. As shown in FIG. Is about three times the etching rate of the RuO ₂ film.

Therefore, in this embodiment, prior to the cleaning process, ruthenium oxide (RuO _x ), which is a main component of the reaction product, is reduced to metal ruthenium (Ru) by hydrogen annealing, and cleaning with ClF ₃ gas or the like is performed in a short time. Make it possible.

It was confirmed by experiments by the present inventors that RuO ₂ which is a typical ruthenium oxide can be reduced to Ru by hydrogen annealing.

Hereinafter, the experimental result will be described.
FIG. 5 shows an evaluation substrate when hydrogen annealing is performed with the RuO ₂ film formed on the evaluation substrate (as depo.) And after the film formation, the temperature is changed to 120 ° C., 150 ° C., and 200 ° C. It is a figure which shows the surface state (morphology). FIG. 6 is a diagram showing an X-ray diffraction pattern when hydrogen annealing is performed at 120 ° C. after the RuO ₂ film is formed on the evaluation substrate and at 226 ° C.

As shown in FIG. 5, it was confirmed that the surface of the evaluation substrate became powdery by hydrogen annealing. In addition, as shown in the X-ray diffraction pattern of FIG. 6, when the hydrogen annealing temperature is 120 ° C., some RuO ₂ remains, but it is reduced to almost Ru, and at 226 ° C., it is completely reduced to Ru. confirmed.

The surface became powdery by hydrogen annealing because the lattice constant of RuO ₂ is about twice that of Ru, and the volume is reduced to about half when reduced from RuO ₂ to Ru. It is considered a thing. The generation of powdery Ru makes it easier to etch than the Ru film, and it is expected that a higher etching rate can be obtained during cleaning.

As described above, in Step 2, by performing hydrogen annealing prior to cleaning with ClF ₃ gas, the reaction product mainly composed of RuO _x is reduced and changed into the reduction product mainly composed of Ru. The cleaning process can be performed in a short time.

The cleaning process in step 3 is performed subsequent to the hydrogen annealing step in step 2.
In the cleaning process, the ClF ₃ gas supply is performed in a state in which the wafer 1 is heated to a predetermined temperature by the heater 5 while the chamber 1 is at a predetermined pressure while the wafer 1 is not present in the chamber 1 following the process 2. A cleaning gas ClF ₃ gas is introduced from the source 53 into the chamber 1 to clean the inside of the chamber 1. As a result, the reduction product mainly made of Ru produced by reduction of the reaction product mainly made of RuOx by hydrogen annealing is etched and removed by the ClF ₃ gas.

The temperature at this time is preferably 180 to 300 ° C. If the cleaning temperature is lower than 180 ° C., the reduction product mainly composed of Ru cannot be sufficiently etched, and if it exceeds 300 ° C., corrosion of members in the processing container becomes a problem due to the cleaning gas. The pressure in the chamber 1 is preferably 5 to 50 Torr (666.5 to 6665 Pa), and the ClF ₃ gas flow rate is preferably 100 to 500 mL / min (sccm).

As described above, Ru, which is a reduction product, essentially has a higher etching rate with ClF ₃ than RuO _x , and the reduction product, Ru, is pulverized, so that the cleaning time can be extremely shortened. it can. Moreover, since cleaning by ClF ₃ is only flowing a ClF ₃ gas while heating the chamber 1, never device cost becomes high as in the case of using the ozone.

As the cleaning gas not only ClF ₃ gas, can be used _{F 2} gas or HF gas instead of ClF ₃ gas may be a ClF ₃ gas, _{F 2} gas, one or more of HF gas . F ₂ gas and HF gas are known to have reactivity similar to ClF ₃ gas, and F ₂ gas and HF gas also have a low etching rate for RuO _x , as with ClF ₃ gas. The etching rate for Ru is high.

The present invention can be variously modified without being limited to the above embodiment. For example, in the above-described embodiment, an example in which a RuO ₂ film is formed mainly using the ruthenium compound of the above formula (1) and O ₂ gas at the time of film formation has been shown. Instead, the present invention can be applied to all cases where a RuO ₂ film is formed by a CVD method (including an ALD method). Further, the apparatus configuration and processing conditions of the present embodiment are merely examples, and are not limited to these. Furthermore, the substrate to be processed is not limited to a semiconductor wafer, and may be another substrate such as an FPD (flat panel display) substrate typified by an LCD (liquid crystal display) substrate or a ceramic substrate.

1; chamber 2; susceptor 5; heater 10, showerhead to 30; the gas supply mechanism 31; film forming material tank 42; _{O 2} gas supply source 44; _{H 2} gas source 53; ClF ₃ gas supply source 60; controller 61 Process controller 63; storage unit 100; film forming apparatus W; semiconductor wafer

Claims (11)

A substrate is accommodated in a processing container, a ruthenium compound is supplied onto the substrate in a gas phase state, and oxygen gas is supplied onto the substrate, and ruthenium oxide is formed on the substrate by a reaction between the ruthenium compound gas and oxygen gas. Forming a film;
Unloading the substrate from within the processing vessel, introducing hydrogen gas into the processing vessel, and annealing the inside of the processing vessel; and
And a step of introducing at least one of ClF ₃ gas, F ₂ gas, and HF gas as a cleaning gas into the processing vessel after the hydrogen annealing to clean the inside of the processing vessel. A method for forming a ruthenium oxide film. The ruthenium compound has a structure of the following formula (1) in which two β-diketones and two groups selected from orphene, amine, nitrile, and carbonyl are coordinated to Ru. The method for forming a ruthenium oxide film according to claim 1.
However, R ₁ and R ₂ are alkyl groups having 2 to 5 total carbon atoms, and R ₃ is a group selected from an orphen group, an amine group, a nitrile group, and a carbonyl group.   The method for forming a ruthenium oxide film according to claim 1 or 2, wherein the hydrogen annealing step is performed at a temperature in the processing vessel of 120 to 300 ° C.   4. The method for forming a ruthenium oxide film according to claim 1, wherein the cleaning step is performed at a temperature in the processing container of 180 to 300 ° C. 5.   5. The reaction product mainly composed of ruthenium oxide produced in the processing vessel is reduced by the hydrogen annealing to become a reduction product mainly composed of metal ruthenium. The method for forming a ruthenium oxide film according to any one of the above. A substrate is accommodated in a processing container, a ruthenium compound is supplied onto the substrate in a gas phase state, and oxygen gas is supplied onto the substrate, and ruthenium oxide is formed on the substrate by a reaction between the ruthenium compound gas and oxygen gas. A ruthenium oxide film deposition processing container cleaning method for cleaning a processing container after performing a film forming process for forming a film,
After the film formation process, in the state where the substrate is not present in the processing container, hydrogen gas is introduced into the processing container to anneal the inside of the processing container,
Thereafter, at least one of ClF ₃ gas, F ₂ gas, and HF gas is introduced into the processing container as a cleaning gas to clean the inside of the processing container. Cleaning method. The ruthenium compound has a structure of the following formula (1) in which two β-diketones and two groups selected from orphene, amine, nitrile, and carbonyl are coordinated to Ru. A method for cleaning a processing container for forming a ruthenium oxide film according to claim 6.
However, R ₁ and R ₂ are alkyl groups having 2 to 5 total carbon atoms, and R ₃ is a group selected from an orphen group, an amine group, a nitrile group, and a carbonyl group.   The method for cleaning a ruthenium oxide film deposition processing container according to claim 6 or 7, wherein the hydrogen annealing is performed at a temperature in the processing container of 120 to 300 ° C.   9. The cleaning method for a ruthenium oxide film-forming treatment container according to claim 6, wherein the cleaning is performed at a temperature of 180 to 300 ° C. in the treatment container. 10. .   The reaction product mainly composed of ruthenium oxide produced in the processing vessel is reduced by the hydrogen annealing to become a reduction product mainly composed of metal ruthenium. The method for cleaning a processing container for ruthenium oxide film formation according to any one of the above.   A storage medium that operates on a computer and stores a program for controlling a film forming apparatus, wherein the program is executed when the ruthenium oxide film is formed according to any one of claims 1 to 5. A storage medium that causes a computer to control the film formation apparatus.