Method for forming ruthenium oxide film and method for manufacturing semiconductor device comprising same

Abstract

A method for forming a ruthenium oxide film according to an embodiment of the present invention may comprise the steps of: forming a ruthenium film by spraying a precursor containing ruthenium (Ru) toward a substrate; forming a ruthenium oxide film by spraying an oxygen-containing gas onto the ruthenium film; and forming plasma to expose the ruthenium oxide film to the plasma. According to embodiments of the present invention, a ruthenium oxide film with a high oxygen content can be formed. Thus, the quality of the ruthenium oxide film can be improved, leading to an enhancement in performance of the ruthenium oxide film included in a semiconductor device.

Description

Method for forming a ruthenium oxide film and method for manufacturing a semiconductor device including the same

[0001] The present invention relates to a method for forming a ruthenium oxide film and a method for manufacturing a semiconductor device including the same, and more particularly, to a method for forming a ruthenium oxide film capable of increasing the oxygen content and a method for manufacturing a semiconductor device including the same.

[0002] A capacitor includes a substrate, a diffusion barrier film formed on the substrate, a lower electrode formed on the diffusion barrier film, a dielectric film formed on the lower electrode, and an upper electrode formed on the dielectric film. The lower electrode may be formed of a ruthenium metal film, and the diffusion barrier film may be formed of a ruthenium oxide film. Here, the diffusion barrier film is a film formed to suppress or prevent ruthenium (Ru) contained in the lower electrode from moving or diffusing to the substrate.

[0003] In forming a ruthenium oxide film, a precursor containing ruthenium (Ru) is sprayed to form a ruthenium metal film on a substrate, and oxygen gas is sprayed toward the ruthenium metal film to form the film. However, ruthenium (Ru) is a noble metal and does not oxidize easily. Therefore, there is a problem that the oxygen content of the ruthenium oxide film is low, and this causes a problem that the performance of the ruthenium oxide film is deteriorated. In other words, there is a problem that the ruthenium oxide film cannot suppress or prevent the migration of ruthenium (Ru) from the lower electrode to the substrate.

[0004] To address the issue of low oxygen content in the ruthenium oxide film, the substrate is heated to a high temperature of 800°C or higher. However, since the ruthenium metal film is formed at a temperature below 500°C, the ruthenium oxide film and the ruthenium metal film cannot be formed in situ. In other words, after forming the ruthenium oxide film in one deposition device, the substrate with the formed ruthenium oxide film must be transferred to another deposition device to form the ruthenium metal film. This complicates the process.

[0005] (Prior art literature)

[0006] (Patent Document 1) Korean Registered Patent KR 0434489

[0007] The present invention provides a method for forming a ruthenium oxide film capable of increasing the oxygen content and a method for manufacturing a semiconductor device including the same.

[0008] The present invention provides a method for forming a ruthenium oxide film capable of forming a ruthenium oxide film by effectively increasing the oxygen content, and a method for manufacturing a semiconductor device including the same.

[0009] A method for forming a ruthenium oxide film according to an embodiment of the present invention may include a step of forming a ruthenium film by spraying a precursor containing ruthenium (Ru) toward a substrate; a step of forming a ruthenium oxide film by spraying an oxygen-containing gas onto the ruthenium film; and a step of forming plasma and exposing the ruthenium oxide film to the plasma.

[0010] In forming the above plasma, the plasma can be formed using an oxygen-containing gas.

[0011] The above oxygen-containing gas may include one or a combination of two or more of oxygen (O2), ozone (O3), and nitrous oxide (N2O).

[0012] The step of forming the plasma includes a step of forming the plasma by additionally using an inert gas in addition to the oxygen-containing gas, and the inert gas may include one or a combination of two or more of argon (Ar) and helium (He).

[0013] The oxygen content of the ruthenium oxide film exposed to the plasma may be higher than the oxygen content of the ruthenium oxide film before exposure to the plasma.

[0014] A film formation cycle (CY) comprising a step of forming the above ruthenium film and a step of forming a ruthenium oxide film f ) is performed multiple times, and multiple film formation cycles (CY f ) can be performed continuously.

[0015] The step of exposing the above ruthenium oxide film to plasma is the film formation cycle (CY f ) can be performed after performing it multiple times in succession.

[0016] In the step of forming the plasma, the step of forming the plasma by additionally using an inert gas in addition to the oxygen-containing gas includes the step of injecting the oxygen-containing gas and the inert gas toward the ruthenium oxide film; and the step of generating plasma by using the injected oxygen-containing gas and the inert gas; and in the step of injecting the oxygen-containing gas and the inert gas, the flow rate of the oxygen-containing gas may be greater than that of the inert gas.

[0017] The above film formation cycle (CY f ) In spraying an oxygen-containing gas, an inert gas is sprayed together, and the inert gas may include one or a combination of two or more of argon (Ar) and helium (He).

[0018] The above film formation cycle (CY f) injecting oxygen-containing gas and inert gas, the flow rate of oxygen-containing gas can be larger than that of inert gas.

[0019] In the step of forming the ruthenium film, the step of forming the ruthenium oxide film, and the step of exposing the plasma, the temperature of the substrate can be controlled to 250°C to 450°C.

[0020]

[0021] A method for manufacturing a semiconductor device according to an embodiment of the present invention includes the steps of forming a ruthenium metal film on a substrate inside a chamber; and the steps of forming a ruthenium oxide film in situ inside the chamber in which the ruthenium metal film was formed before or after the step of forming the ruthenium metal film; wherein the step of forming the ruthenium oxide film may include the method for forming the ruthenium oxide film described above.

[0022] In the step of forming the ruthenium metal film and the step of forming the ruthenium oxide film, the temperature of the substrate can be controlled to 250°C to 450°C.

[0023] According to embodiments of the present invention, a ruthenium oxide film with a high oxygen content can be formed. Accordingly, the quality of the ruthenium oxide film can be improved, and thus the performance of the ruthenium oxide film included in a semiconductor device can be improved.

[0024] FIG. 1 is a conceptual diagram illustrating a semiconductor device including a ruthenium oxide (RuO2) film formed by a method according to embodiments of the present invention.

[0025] FIG. 2 is a conceptual diagram for explaining a method for forming a ruthenium oxide film according to a first embodiment of the present invention.

[0026] Figures 3 (a) to (c) illustrate the deposition step (P) according to the first embodiment of the present invention. f ) is a process diagram to explain.

[0027] Figure 4 is a plasma exposure step (P) according to the first embodiment of the present invention. p ) is a process diagram to explain.

[0028] FIG. 5 is a conceptual diagram for explaining a method for forming a ruthenium oxide film according to a second embodiment of the present invention.

[0029] FIG. 6 is a drawing showing a case where a ruthenium oxide (RuO2) film formed by a method according to embodiments of the present invention is formed on top of a ruthenium metal film.

[0030] FIG. 7 is a drawing showing a case where a ruthenium oxide (RuO2) film formed by a method according to embodiments of the present invention is formed between a substrate and a ruthenium metal film, on top of the ruthenium metal film.

[0031] Hereinafter, embodiments of the present invention will be described in more detail with reference to the attached drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms. These embodiments are provided solely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention. To illustrate the embodiments of the present invention, the drawings may be exaggerated, and like reference numerals in the drawings represent like components.

[0032]

[0033] The present invention relates to a method for forming a ruthenium oxide film capable of improving the quality of a ruthenium oxide (RuO2) film. More specifically, the present invention relates to a method for forming a ruthenium oxide film capable of forming a ruthenium oxide film with an improved oxygen content.

[0034]

[0035] FIG. 1 is a conceptual diagram illustrating a semiconductor device including a ruthenium oxide (RuO2) film formed by a method according to embodiments of the present invention.

[0036] A semiconductor device including a ruthenium oxide (RuO2) film may be, for example, a capacitor. Referring to FIG. 1, the capacitor may include a substrate (S), a lower conductive film (10) formed on the substrate (S), a dielectric film (20) formed on the lower conductive film (10), and an upper conductive film (30) formed on the dielectric film (20).

[0037] The substrate (S) may be a semiconductor substrate. More specifically, the substrate (S) may be a wafer, and may be any one of a Si wafer, a GaAs wafer, and a SiGe wafer. Of course, the substrate (S) may be made of any one of glass, metal, plastic, a polymer film, and a dielectric material.

[0038] The dielectric film (20) may be formed of a dielectric material including a metal oxide. As a more specific example, the dielectric film (20) may be formed of any one of ZrO2, Al2O3, TiO2, TaO2, and HfO2.

[0039] The lower conductive film (10) and the upper conductive film (30) are formed of a conductive material. At this time, the lower conductive film (10) may be formed of a ruthenium (Ru) metal film, and the upper conductive film (30) may be formed of a conductive material other than ruthenium (Ru). Of course, the upper conductive film (30) may be formed of a ruthenium (Ru) metal film, and the lower conductive film (10) may be formed of a conductive material other than ruthenium (Ru). In addition, the lower conductive film (10) and the upper conductive film (30) may also be formed of a ruthenium metal film.

[0040] Hereinafter, it will be described that the lower conductive film (10) is formed of a ruthenium metal film. Accordingly, for convenience of explanation, the lower conductive film and the ruthenium metal film are referred to by the same drawing reference numeral '10'.

[0041] Meanwhile, if a lower conductive film (10) made of a ruthenium metal film is directly formed on one side of a substrate (S), for example, a Si wafer, ruthenium (Ru) contained in the lower conductive film (10) may migrate or diffuse to the substrate (S). This may deteriorate the performance of the semiconductor device. Therefore, as shown in Fig. 1, a ruthenium oxide film (100) is formed between the substrate (S) and the lower conductive film (10). At this time, the ruthenium oxide film (100) plays a role in suppressing or preventing ruthenium (Ru) contained in the lower conductive film (10) from migrating to the substrate (S). That is, the ruthenium oxide film (100) formed between the substrate (S) and the lower conductive film (10) is a diffusion barrier film that suppresses or prevents the migration of ruthenium (Ru).

[0042] The ruthenium oxide film (100) formed by the method according to the embodiments may be a diffusion barrier film formed between the substrate (S) and the lower conductive film (10) as shown in FIG. 1.

[0043] Here, the ruthenium oxide film (100) and the lower conductive film (10) laminated on the substrate (S) may constitute a lower electrode. That is, the lower electrode may include a ruthenium oxide film (100) formed on the substrate (S) and a lower conductive film (10) formed on the ruthenium oxide film (100). In addition, the upper conductive film (30) may be an upper electrode.

[0044]

[0045] Hereinafter, a method for forming a ruthenium oxide film according to a first embodiment of the present invention will be described with reference to FIGS. 2 to 4. Here, forming a ruthenium oxide film on one surface of a substrate (S) will be described as an example.

[0046] Figure 2 is a conceptual diagram for explaining a method for forming a ruthenium oxide film according to a first embodiment of the present invention. Figures 3 (a) to (c) illustrate a film forming step (P) according to the first embodiment of the present invention. f) is a process diagram for explaining the plasma exposure step (P) according to the first embodiment of the present invention. p ) is a process diagram to explain.

[0047] In FIG. 2, 'on' means spraying raw materials or gas for film formation or generating plasma, and 'off' may mean stopping or ending spraying of the raw materials or gas, or not generating plasma.

[0048] Referring to FIG. 2, the method for forming a ruthenium oxide film includes a film forming step (P) of forming a ruthenium oxide (RuO2) film. f ) and membrane formation stage (P f ) to increase the oxygen content of the ruthenium oxide (RuO2) film by exposing the film to plasma (P p ) may be included.

[0049] For convenience of explanation, the film formation step (P) is described below. f ) is named as the 'primary ruthenium oxide film (110)' and the film formation step (P f ) is formed by exposing the primary ruthenium oxide film (110) to plasma and the film formed is named ‘secondary ruthenium oxide film (100)’.

[0050] Reflecting this, the method for forming a ruthenium oxide film (100) is described again as follows. The method for forming a ruthenium oxide film (100) includes a film forming step (P) for forming a first ruthenium oxide film (110). f ) and a plasma exposure step (P) in which a secondary ruthenium oxide film (100) is formed by exposing the primary ruthenium oxide film (110) to plasma, which is a ruthenium oxide film with increased oxygen content compared to the primary ruthenium oxide film (110). p ) may be included.

[0051] Membrane formation stage (P f) and plasma exposure stage (P p ) can be defined as one process cycle (CY). In other words, the 'film formation step (P f ) - Plasma exposure stage (P p )' sequence can be defined as one process cycle (CY). In addition, the process cycle (CY) can be performed multiple times.

[0052] Here, the primary ruthenium oxide film (110) is a ruthenium oxide film formed by oxidizing ruthenium, and the secondary ruthenium oxide film (100) is a ruthenium oxide film formed after exposing the primary ruthenium oxide film (110) to plasma. Therefore, both the primary ruthenium oxide film (110) and the secondary ruthenium oxide film (100) can be referred to as ruthenium oxide (RuO2) films. However, the primary ruthenium oxide film (110) and the secondary ruthenium oxide film (100) formed by the method according to the embodiment have a difference in the oxygen content. That is, the primary ruthenium oxide film (100) has a higher oxygen content than the primary ruthenium oxide film (110).

[0053] In addition, the secondary ruthenium oxide film (100) is a ruthenium oxide film, which is a final product to be formed by the method according to the embodiment. Accordingly, the ruthenium oxide film, which is a final product to be formed by the method according to the embodiment, and the secondary ruthenium oxide film may be described with the same drawing reference numeral. That is, the drawing reference numeral '100' described below may mean both the secondary ruthenium oxide film and the ruthenium oxide film, which is a final product.

[0054]

[0055] Below, first, referring to FIGS. 2 and 3, the film formation step (P f ) is explained.

[0056] Referring to (a) to (c) of FIG. 2 and FIG. 3, the film formation step (P f) includes a step of forming a ruthenium film (111) by spraying a precursor containing ruthenium (Ru) toward a substrate (S) (precursor spraying step) and a step of forming a primary ruthenium oxide film (110) by spraying an oxygen-containing gas toward the ruthenium film (111).

[0057] Additionally, the membrane formation stage (P f ) may further include at least one of a step of injecting a purge gas between the precursor injection step and the oxygen-containing gas injection step (first purge step) and a step of injecting a purge gas after the oxygen-containing gas injection step ends (second purge step). Here, argon (Ar) gas may be used as the purge gas.

[0058] In addition, 'precursor injection stage - 1st purge stage - oxygen-containing gas injection stage - 2nd purge stage' is one cycle (hereinafter, film formation cycle (CY) f )) can be done. That is, the film formation stage (P f ) is the membrane formation cycle (CY f ) may include a membrane formation cycle (CY f ) may include 'precursor injection step - first purge step - oxygen-containing gas injection step - second purge step'. And, film formation step (P f ) is a multiple membrane formation cycle (CY f ) may include multiple film formation cycles (CY f ) can be performed continuously. In addition, the film formation cycle (CY f ) at least one of the first and second fuzzy steps may be omitted.

[0059] Below is the membrane formation cycle (CY f ) is explained in more detail for each step.

[0060] In the step of spraying a precursor, a precursor containing or including ruthenium (Ru) is sprayed toward the substrate (S). That is, the precursor containing ruthenium (Ru) is sprayed into the interior of the chamber in which the substrate (S) is loaded. Here, as the precursor raw material containing ruthenium (Ru), for example, ethylcyclopentadienyl ruthenium ((EtCp)2Ru)(Bis(ethylcyclopentadienyl)ruthenium) can be used. When the precursor containing ruthenium (Ru) is sprayed in this way, the precursor is deposited or adsorbed on one surface of the substrate (S), thereby forming a film containing ruthenium (Ru), i.e., a ruthenium film (111), as shown in (a) of FIG. 3.

[0061] When the precursor injection step is completed, a purge gas is injected into the chamber where the substrate (S) is loaded to perform a primary purge. At this time, the purge gas can be, for example, argon (Ar) gas.

[0062] When the first purge is completed, an oxygen-containing gas is injected into the chamber in which the substrate (S) is loaded, as shown in (b) of Fig. 3. Here, the oxygen-containing gas may include, for example, one or a combination of two or more gases from among oxygen (O2), ozone (O3), and nitrous oxide (N2O). When the oxygen-containing gas is injected, oxygen (O) penetrates into the ruthenium film (111), and the ruthenium film (111) and oxygen (O) react. That is, the ruthenium film (111) may react with the oxygen contained in the oxygen-containing gas and be oxidized. As a result, a primary ruthenium oxide film (110), which is a ruthenium oxide (RuO2) film containing ruthenium (Ru) and oxygen, is formed.

[0063] Membrane formation stage (P f ) can be named as a ‘reactant gas’ because it is a gas injected to react with the ruthenium film (111). Accordingly, the reactant gas can be explained as an oxygen-containing gas.

[0064] After the step of injecting oxygen-containing gas is completed, a second purge is performed by injecting purge gas into the chamber in which the substrate (S) is loaded. At this time, the same gas as in the first purge step can be used as the purge gas, and for example, argon (Ar) gas can be used.

[0065] In carrying out the precursor injection step, the first purge step, the oxygen-containing gas injection step, and the second purge step as described above, it can be carried out while the temperature of the substrate (S) is controlled to 250°C to 450°C. That is, the film formation cycle (CY) is carried out while the temperature of the substrate (S) is controlled to 250°C to 450°C. f ) is performed. More specifically, the temperature of the susceptor installed inside the chamber of the deposition device is controlled to control the temperature of the substrate (S) supported on the susceptor to 250°C to 450°C. Then, a film formation cycle (CY) is performed in which precursor, purge gas, and oxygen-containing gas are injected into the chamber. f ) is performed. As a result, a primary ruthenium oxide film (110), which is a ruthenium oxide film, is formed on the substrate (S).

[0066] Afterwards, a film formation cycle (CY) including a precursor injection step, a first purge step, an oxygen-containing gas injection step, and a second purge step as described above f ) is repeated multiple times. Accordingly, multiple primary ruthenium oxide films (110) are laminated on the substrate (S) as shown in (c) of Fig. 3.

[0067] In Fig. 3 (c), multiple film formation cycles (CY f ) are shown separately, but the plurality of stacked primary ruthenium oxide films (110) may be integral.

[0068]

[0069] As described above, when an oxygen-containing gas is sprayed toward a ruthenium film (111), ruthenium (Ru) contained in the ruthenium film (111) reacts with oxygen to form a primary ruthenium oxide film (110), which is a ruthenium oxide film. However, the primary ruthenium oxide film (110) formed in this way has a low oxygen (O) content. To be more specific, the primary ruthenium oxide film (110) may have a low oxygen (O) content compared to the ruthenium (Ru) content, or the ruthenium (Ru) content may be the same as the oxygen (O). In other words, the ratio of the ruthenium (Ru) content and the oxygen (O) content contained in the primary ruthenium oxide film (110) may be 1:1 or less (ruthenium content: oxygen content = 1:1 or less). Here, a ratio of ruthenium (Ru) content to oxygen (O) content of 1:1 may mean that the content of ruthenium (Ru) and the content of oxygen (O) are the same, and a ratio of ruthenium (Ru) content to oxygen (O) content of less than 1:1 may mean that the content of oxygen is less than the content of ruthenium (Ru).

[0070] If the oxygen content in the ruthenium oxide film is low, the function of the ruthenium oxide film may be degraded. To explain this in more detail, a case in which a ruthenium oxide film (100) is formed between a lower conductive film (10) and a substrate (S) as described in Fig. 1 will be described as an example. Here, the ruthenium oxide film (100) is a diffusion barrier film.

[0071] When the content of oxygen contained in the ruthenium oxide film (100) is low, the ruthenium oxide film (100) may not be able to suppress or prevent ruthenium (Ru) contained in the lower conductive film (10) from moving to the substrate (S). That is, the content of oxygen (O) contained in the ruthenium oxide film (100) is low, resulting in a deterioration in the quality of the film as a diffusion barrier film.

[0072] Therefore, in the embodiment, the film formation step (P f) is exposed to plasma to increase the content of oxygen (O) contained in the primary ruthenium oxide film (110). In other words, by exposing the primary ruthenium oxide film (110) to plasma, a secondary ruthenium oxide film (100) having an increased content of oxygen compared to the primary ruthenium oxide film (110) is formed. At this time, a plasma containing oxygen (oxygen plasma) is formed, and the primary ruthenium oxide film (110) is exposed to oxygen plasma, so that a secondary ruthenium oxide film (100) having an increased content of oxygen can be formed.

[0073]

[0074] Hereinafter, referring to FIG. 2 and FIG. 4, a plasma exposure step (P) for forming a secondary ruthenium oxide film (100) p ) is explained.

[0075] Referring to Figure 2, the plasma exposure step (P p ) includes a step of generating an oxygen-containing plasma by injecting an oxygen-containing gas. That is, the plasma exposure step (P p) includes a step of injecting an oxygen-containing gas into a chamber in which a substrate (S) is loaded or toward the substrate (S), and a step of generating oxygen plasma using the injected oxygen-containing gas. In addition, the step of generating the oxygen plasma may include a step of applying power for plasma generation. At this time, for example, RF (Radio Frequency) power may be applied to at least one of the chamber, the susceptor on which the substrate (S) is placed inside the chamber, and the injection unit that injects the oxygen-containing gas into the interior of the chamber. In addition, the oxygen-containing gas may include, for example, one or a combination of two or more gases from among oxygen (O2), ozone (O3), and nitrous oxide (N2O). In this way, when RF power is applied and the oxygen-containing gas is injected, a plasma containing oxygen, i.e., oxygen plasma, may be generated inside the chamber. Accordingly, as shown in FIG. 4, the primary ruthenium oxide film (110) formed on the substrate (S) is exposed to the oxygen plasma.

[0076] When the primary ruthenium oxide film (110) is exposed to oxygen plasma, the oxygen (O) contained in the oxygen plasma penetrates into the primary ruthenium oxide film (110). That is, the oxygen ions generated when the oxygen plasma is formed penetrate into the primary ruthenium oxide film (110). At this time, compared to not forming oxygen plasma and only spraying an oxygen-containing gas, when oxygen plasma is formed, the amount of oxygen penetrating into the primary ruthenium oxide film (110) can be increased. This will be described in more detail as follows. The oxygen contained in the oxygen-containing gas is non-ionized oxygen. However, when plasma is generated by spraying an oxygen-containing gas, oxygen ions are generated. In addition, the speed at which ionized oxygen (oxygen ions) moves toward the primary ruthenium oxide film (110) is greater than the speed at which non-ionized oxygen moves toward the primary ruthenium oxide film (110). Accordingly, by forming oxygen plasma after forming the primary ruthenium oxide film (110), the content of oxygen contained in the primary ruthenium oxide film (110) can be increased. In addition, compared to simply injecting oxygen-containing gas into the primary ruthenium oxide film (without generating oxygen plasma) after forming the primary ruthenium oxide film (110), when forming oxygen plasma, the amount of oxygen penetrating into the primary ruthenium oxide film (110) can be effectively increased.

[0077] Accordingly, a secondary ruthenium oxide film (100), which is a ruthenium oxide film having an increased oxygen content compared to the primary ruthenium oxide film (110), can be formed. At this time, the secondary ruthenium oxide film (100) may have a higher oxygen (O) content than the ruthenium (Ru) content. In other words, the ratio of the ruthenium (Ru) content to the oxygen (0) content may exceed 1:1 (ruthenium content: oxygen content = exceeding 1:1). More specifically, the ratio of the ruthenium (Ru) content to the oxygen (0) content may be 1:2 or more (ruthenium content: oxygen content = 1:2 or more).

[0078] In this way, if the content of oxygen contained in the secondary ruthenium oxide film (100) is high, the function of the secondary ruthenium oxide film (100) can be improved. To explain this in more detail, an example of forming a ruthenium oxide film between the lower conductive film (10) and the substrate (S) as described in FIG. 1 will be described. Here, the ruthenium oxide film (100) is a diffusion barrier film, and is a secondary ruthenium oxide film formed through the processes of FIG. 3 (a) and (b) and FIG. 4. Accordingly, the reference numeral '100' illustrated in FIG. 1 will be referred to as a 'ruthenium oxide film' and described.

[0079] As the oxygen content of the ruthenium oxide film (100) formed between the lower conductive film (10) and the substrate (S) increases, the ruthenium oxide film (100) can effectively suppress or prevent ruthenium (Ru) contained in the lower conductive film (10) from moving to the substrate (S). That is, as the oxygen (O) content contained in the ruthenium oxide film (100) increases, the function of the ruthenium oxide film (100) as a diffusion barrier film is improved.

[0080] And the plasma exposure stage (P p ) the temperature of the substrate (S) is the same as the film formation step (P) described above. f ) may be the same as the temperature in the plasma exposure stage (Pp ) is performed, the temperature of the substrate (S) is determined during the film formation stage (P f ) can be controlled by a difference of ± 30℃. As a more specific example, the plasma exposure stage (P p ) can be adjusted to the temperature of the substrate (S) from 250°C to 450°C. At this time, the method for adjusting the temperature of the substrate (S) is the film formation step (P) described above. f ) is the same, so its explanation is omitted.

[0081] In this way, even if the temperature of the substrate (S) is controlled to a low temperature of 250°C to 450°C, a ruthenium oxide film with an improved oxygen content can be formed. That is, in the past, the temperature of the substrate was controlled to a high temperature of about 800°C in order to increase the oxygen content of the ruthenium oxide film. On the other hand, in the embodiment, even if the substrate (S) is heated to a low temperature of 250°C to 450°C, a ruthenium oxide film (100) with an improved oxygen content can be formed. This is because, after forming the primary ruthenium oxide film (110), the primary ruthenium oxide film (110) is exposed to oxygen plasma. That is, by exposing the primary ruthenium oxide film (110) to oxygen plasma, oxygen can sufficiently penetrate into the primary ruthenium oxide film (110) even if the substrate (S) is not heated to a high temperature of about 800°C. Therefore, a ruthenium oxide film (100) containing sufficient oxygen can be formed at a low temperature of 250°C to 450°C.

[0082] In addition, the ruthenium metal film (10) formed on the lower or upper portion of the ruthenium oxide film (100) is formed at 250°C to 450°C. Accordingly, the ruthenium oxide film (100) and the ruthenium metal film (10) can be formed in situ. That is, after the ruthenium oxide film (100) is formed inside the chamber of a deposition device, the ruthenium metal film (10) can be formed inside the chamber in which the ruthenium oxide film (100) was formed. Therefore, in laminating the ruthenium oxide film (100) and the ruthenium metal film (10), the process is simplified and there is an effect of saving time.

[0083]

[0084] FIG. 5 is a conceptual diagram for explaining a method for forming a ruthenium oxide film according to a second embodiment of the present invention.

[0085] In FIG. 5, 'on' means spraying raw materials or gas for film formation or generating plasma, and 'off' may mean stopping or ending spraying of the raw materials or gas, or not generating plasma.

[0086] In the first embodiment described in FIGS. 2 and 3, the film forming step (P f ) and plasma exposure stage (P p ) was described as spraying oxygen-containing gas. However, it is not limited to this, and the film formation step (P f ) and plasma exposure stage (P p ) When injecting oxygen-containing gas, an inert gas can be injected together.

[0087] Hereinafter, with reference to FIG. 5, a method for forming a ruthenium oxide film according to a second embodiment of the present invention will be described. At this time, descriptions overlapping with those of the first embodiment will be omitted or briefly described.

[0088] Referring to FIG. 5, the method for forming a ruthenium oxide film according to the second embodiment includes a film forming step (P) for forming a primary ruthenium oxide film (110). f ) and a plasma exposure step (P) in which the primary ruthenium oxide film (110) is exposed to a plasma containing oxygen to form a secondary ruthenium oxide film (100) with increased oxygen content. p ) may be included.

[0089] And, the membrane formation stage (P f ) includes a precursor injection step of forming a ruthenium film (111) by injecting a precursor containing ruthenium (Ru) toward a substrate (S) and a step of forming a primary ruthenium oxide film (110) which is an oxide ruthenium film by injecting an oxygen-containing gas toward the ruthenium film (111).

[0090] Additionally, the membrane formation stage (P f ) may further include at least one of a step of injecting a purge gas between the precursor injection step and the oxygen-containing gas injection step (first purge step) and a step of injecting a purge gas after the oxygen-containing gas injection step is completed (second purge step). Here, argon (Ar) gas may be used as the purge gas.

[0091] In summary, the film forming step (P) according to the second embodiment f ) may include a precursor injection step, a first purge step, an oxygen-containing gas injection step, and a second purge step. And, 'precursor injection step - first purge step - oxygen-containing gas injection step - second purge step' is one film formation cycle (CY f ) can be used.

[0092] In the method according to the second embodiment, the precursor injection step, the first purge step, and the second purge step are performed in the same manner as in the method described in the first embodiment. Therefore, a description of these steps is omitted.

[0093] Film formation step according to the second embodiment (P f) is injected together with an inert gas. That is, when injecting an oxygen-containing gas into the ruthenium film (111), an inert gas is injected together. At this time, the inert gas may include one or a combination of two or more gases among argon (Ar) and helium (He). The reason for injecting the oxygen-containing gas and the inert gas together is that the plasma exposure step (P) performed thereafter p ) because plasma is formed using oxygen-containing gas and inert gas.

[0094] Membrane formation stage (P f ) for the specific reason for injecting oxygen-containing gas and inert gas together, see the plasma exposure stage (P p ) will be explained again after explaining it first.

[0095] Referring to Figure 5, the plasma exposure step (P p ) includes a step of injecting an oxygen-containing gas and an inert gas, and a step of generating plasma using the injected oxygen-containing gas and inert gas. At this time, the inert gas may include one or a combination of two or more of argon (Ar) and helium (He). In this way, in the second embodiment, since plasma is generated by injecting an oxygen-containing gas and an inert gas, the plasma generated at this time is a plasma containing oxygen and an inert element (one or a combination of two or more of Ar and He). Therefore, the plasma containing oxygen and an inert element may be referred to as a mixed plasma.

[0096] The step of generating a mixed plasma using an oxygen-containing gas and an inert gas may be the same as in the first embodiment, except that the inert gas is additionally supplied. That is, the step of generating a mixed plasma includes the step of injecting an oxygen-containing gas and an inert gas into the interior of a chamber in which a substrate (S) is loaded or toward the substrate (S), and the step of generating plasma using the injected oxygen-containing gas and inert gas. In addition, the step of generating plasma may include the step of applying power for plasma generation. At this time, for example, RF (Radio Frequency) power may be applied to at least one of the chamber, the susceptor on which the substrate (S) is mounted inside the chamber, and the injection unit that injects the oxygen-containing gas into the chamber. The oxygen-containing gas may include, for example, one or a combination of two or more of oxygen (O2), ozone (O3), and nitrous oxide (N2O). The injection unit may inject a mixture of the oxygen-containing gas and the inert gas. Of course, separate injection units for injecting oxygen-containing gas and injection units for injecting inert gas may be provided, so that the oxygen-containing gas and inert gas can be injected through separate injection units. When the oxygen-containing gas and inert gas are injected in this way and RF power is applied, a plasma containing oxygen and inert elements, i.e., a mixed plasma, is generated inside the chamber. Accordingly, the primary ruthenium oxide film (110) formed on the substrate (S) is exposed to the mixed plasma.

[0097] When the primary ruthenium oxide film (110) is exposed to the mixed plasma, oxygen (O) penetrates into the primary ruthenium oxide film (110). That is, the oxygen ions generated when the mixed plasma is generated move to and penetrate the primary ruthenium oxide film (110). At this time, by injecting an inert gas together with an oxygen-containing gas to generate plasma, oxygen can be more effectively penetrated into the primary ruthenium oxide film (110). That is, the oxygen content can be more effectively increased to form the secondary ruthenium oxide film (100).

[0098] This is because the density of the mixed plasma formed by injecting both an oxygen-containing gas and an inert gas is higher than that of the plasma formed by injecting only an oxygen-containing gas. More specifically, inert elements such as argon (Ar) and helium (He) can be discharged at lower energy than oxygen. Therefore, the density of the mixed plasma formed by injecting both an oxygen-containing gas and an inert gas (one or a combination of two or more of argon (Ar) and helium (He)) is higher than that of the plasma formed by injecting only an oxygen-containing gas. In other words, a high-density plasma can be formed by injecting and discharging an oxygen-containing gas and an inert gas. In addition, when the density of the plasma increases, the speed at which oxygen ions move to the primary ruthenium oxide film (110) can increase, and thus the amount of oxygen ions penetrating into the primary ruthenium oxide film (110) during the same period of time can increase.

[0099] Therefore, by exposing the primary ruthenium oxide film to the mixed plasma generated by injecting an oxygen-containing gas and an inert gas, the oxygen content contained in the primary ruthenium oxide film (110) can be more effectively increased. That is, compared to when forming oxygen plasma by injecting only an oxygen-containing gas (the first embodiment), when forming a mixed plasma by injecting an oxygen-containing gas and an inert gas (the second embodiment), the amount of oxygen penetrating into the primary ruthenium oxide film (110) can be effectively increased. Accordingly, the secondary ruthenium oxide film (100) can be formed by more effectively increasing the oxygen content in the second embodiment compared to the first embodiment. In other words, the oxygen content of the ruthenium oxide film (100) can be more effectively increased in the second embodiment compared to the first embodiment.

[0100] In this way, the plasma exposure stage (P p ) to form plasma by additionally injecting an inert gas in addition to an oxygen-containing gas. Accordingly, in the second embodiment, the plasma exposure step (P p ) prior to the membrane formation step (P f ) when injecting oxygen-containing gas, an inert gas is injected together. That is, in the film formation stage (P f ) In the oxygen-containing gas injection step, oxygen-containing gas and inert gas are injected together. And, in the film formation step (P f ) and plasma exposure stage (P p ) It is desirable to use the same type of inert gas as the inert gas injected in the plasma exposure stage (P p ) to form plasma by injecting oxygen-containing gas and inert gas, in order to form plasma stably. For example, in the film formation stage (P f ) was injected only with oxygen-containing gas without inert gas during the oxygen-containing gas injection step. And then, in the plasma exposure step (Pp ) to form plasma by injecting oxygen-containing gas and inert gas together. In this case, there is a problem that the plasma energy increases rapidly due to the inert gas. That is, the film formation stage (P f ) is maintained in a state where there is no inert gas inside the chamber, and then the plasma exposure stage (P p ) When plasma is generated by supplying an inert gas into the chamber, the plasma energy may rapidly increase due to the inert gas, which may generate an unstable plasma. This is because argon (Ar) and helium (He) are easily discharged at lower energies than oxygen.

[0101] Therefore, the film forming step (P) according to the second embodiment f ) In the oxygen-containing gas injection step, oxygen-containing gas and inert gas are injected together. Accordingly, in the plasma exposure step (P p ) can stably form plasma.

[0102]

[0103] FIG. 6 is a drawing showing a case where a ruthenium oxide (RuO2) film formed by a method according to embodiments of the present invention is formed on top of a ruthenium metal film. FIG. 7 is a drawing showing a case where a ruthenium oxide (RuO2) film formed by a method according to embodiments of the present invention is formed between a substrate and a ruthenium metal film, on top of the ruthenium metal film.

[0104] In the above-described drawing 1, the formation of a ruthenium oxide film (100) between a substrate (S) and a ruthenium metal film (10) is described. However, the present invention is not limited thereto, and a ruthenium oxide (RuO2) film formed by a method according to an embodiment may be formed at various locations.

[0105] For example, as illustrated in FIG. 6, a ruthenium oxide film (100) may be formed on top of a ruthenium metal film (10). Here, the ruthenium metal film (10) and the ruthenium oxide film (100) formed on top of the ruthenium metal film (10) may constitute an electrode. That is, the electrode may include the ruthenium metal film (10) and the ruthenium oxide film (100) formed on top of the ruthenium metal film (10).

[0106] The ruthenium oxide film (100) formed on top of the ruthenium metal film (10) increases the work function of the electrode. That is, the ruthenium metal film (10) has a low work function, and the ruthenium oxide film (100) has a higher work function than the ruthenium metal film (10). Therefore, by forming the ruthenium oxide film (100) on top of the ruthenium metal film (10), the work function of the electrode can be improved. And as the work function of the electrode is improved, the leakage current can be reduced.

[0107] As another example, as illustrated in FIG. 7, a ruthenium oxide film (100) may be formed on each of the lower and upper portions of a ruthenium metal film (10). Here, the ruthenium metal film (10), the ruthenium oxide film (100) formed on the upper and lower portions of the ruthenium metal film (10), and the ruthenium oxide film (100) formed on the lower portion may constitute an electrode. That is, the electrode may include the ruthenium metal film (10), the ruthenium oxide film (100) formed on the lower portion of the ruthenium metal film (10), and the ruthenium oxide film (100) formed on the upper portion of the ruthenium metal film (10).

[0108] Here, the ruthenium oxide film (100) formed on the lower portion of the ruthenium metal film (10) acts as a diffusion barrier film that suppresses or prevents ruthenium (Ru) of the ruthenium metal film (10) from moving to the substrate (S). In addition, the ruthenium oxide film (100) formed on the upper portion of the ruthenium metal film (10) can improve the work function of the electrode.

[0109]

[0110] According to the method for forming a ruthenium oxide film according to the embodiments, a ruthenium oxide film (100) having a high oxygen content can be formed. That is, after forming a primary ruthenium oxide film (110) by spraying an oxygen-containing gas onto a ruthenium film (111) which is a noble metal, oxygen can be easily permeated into the primary ruthenium oxide film (110) by exposing the primary ruthenium oxide film (110) to plasma. That is, the amount of oxygen permeating into the primary ruthenium oxide film (110) can be increased. Accordingly, a secondary ruthenium oxide film (100) having an increased oxygen content compared to the primary ruthenium oxide film (110) can be formed. Therefore, a ruthenium oxide film (RuO2) having a higher oxygen content compared to a conventional film can be formed, thereby improving the quality of the ruthenium oxide film (100). That is, the performance of the ruthenium oxide film (100) included in the semiconductor device can be improved.

[0111] According to embodiments of the present invention, a ruthenium oxide film with a high oxygen content can be formed. Accordingly, the quality of the ruthenium oxide film can be improved, and thus the performance of the ruthenium oxide film included in a semiconductor device can be improved.

Claims

1. A step of forming a ruthenium film by spraying a precursor containing ruthenium (Ru) toward a substrate; A step of forming a ruthenium oxide film by spraying an oxygen-containing gas onto the ruthenium film; and A method for forming a ruthenium oxide film, comprising the step of forming plasma and exposing the ruthenium oxide film to plasma.

2. In claim 1, In forming the above plasma, A method for forming a ruthenium oxide film by forming a plasma using an oxygen-containing gas.

3. In claim 2, The above oxygen-containing gas is, A method for forming a ruthenium oxide film comprising one or more gases selected from the group consisting of oxygen (O2), ozone (O3) and nitrous oxide (N2O).

4. In claim 2, The step of forming the plasma includes a step of forming the plasma by additionally using an inert gas in addition to the oxygen-containing gas, A method for forming a ruthenium oxide film, wherein the above inert gas includes one or a combination of two or more gases selected from argon (Ar) and helium (He).

5. In claim 1, A method for forming a ruthenium oxide film, wherein the oxygen content of the ruthenium oxide film exposed to the plasma is higher than the oxygen content of the ruthenium oxide film before exposure to the plasma.

6. In claim 1, A film formation cycle (CY) comprising a step of forming the above ruthenium film and a step of forming a ruthenium oxide film f ) is performed multiple times, and multiple film formation cycles (CY f ) is continuously performed to form a ruthenium oxide film.

7. In claim 6, The step of exposing the above ruthenium oxide film to plasma is the film formation cycle (CY f ) is performed multiple times in succession to form a ruthenium oxide film.

8. In claim 4, In the step of forming the plasma, the step of forming the plasma by additionally using an inert gas in addition to the oxygen-containing gas is as follows: A step of spraying an oxygen-containing gas and an inert gas toward the above ruthenium oxide film; and A step of generating plasma using injected oxygen-containing gas and an inert gas; A method for forming a ruthenium oxide film, wherein the oxygen-containing gas and the inert gas are injected so that the flow rate of the oxygen-containing gas is greater than that of the inert gas.

9. In claim 6, The above film formation cycle (CY f ) Injecting oxygen-containing gas, an inert gas is injected together, A method for forming a ruthenium oxide film, wherein the above inert gas includes one or a combination of two or more gases selected from argon (Ar) and helium (He).

10. In claim 9, The above film formation cycle (CY f ) A method for forming a ruthenium oxide film by injecting oxygen-containing gas and inert gas so that the flow rate of oxygen-containing gas is greater than that of inert gas.

11. In any one of claims 1 to 10, A method for forming a ruthenium oxide film, wherein the temperature of the substrate is controlled to 250°C to 450°C in the step of forming the ruthenium film, the step of forming the ruthenium oxide film, and the step of exposing the plasma.

12. A step of forming a ruthenium metal film on a substrate inside the chamber; and A step of forming a ruthenium oxide film in situ inside a chamber in which the ruthenium metal film is formed before or after the step of forming the ruthenium metal film; A method for manufacturing a semiconductor device, wherein the step of forming the ruthenium oxide film is formed by the method for forming the ruthenium oxide film described in any one of claims 1 to 10.

13. In claim 12, A method for manufacturing a semiconductor device, wherein the temperature of the substrate is controlled to 250°C to 450°C in the step of forming the ruthenium metal film and the step of forming the ruthenium oxide film.

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