Method for forming a ruthenium oxide film and method for manufacturing a semiconductor device equipped therewith

Abstract

A method for forming a ruthenium oxide film according to an embodiment of the present invention may include 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 toward the ruthenium film; and forming a plasma to expose the ruthenium oxide film to the plasma. Therefore, according to embodiments of the present invention, a ruthenium oxide film with a high oxygen content can be formed. This improves the quality of the ruthenium oxide film, thereby improving the performance of the ruthenium oxide film provided in semiconductor devices.

Description

[Technical Field]

[0001] The present invention relates to a method for forming a ruthenium oxide film and a method for manufacturing a semiconductor device equipped therewith, 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 equipped therewith. [Background technology]

[0002] A capacitor comprises 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 is formed of a ruthenium metal film, and the diffusion barrier film can be formed of a ruthenium oxide film. Here, the diffusion barrier film is a film formed to inhibit or prevent ruthenium (Ru) contained in the lower electrode from moving or diffusing into the substrate.

[0003] In forming a ruthenium oxide film, a precursor containing ruthenium (Ru) is sprayed onto the substrate to form a ruthenium metal film, and then oxygen gas is sprayed onto the ruthenium metal film to complete the formation. 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, which leads to a decrease in the performance of the ruthenium oxide film. 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 solve the problem 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 of 500 °C or lower, the ruthenium oxide film and the ruthenium metal film cannot be formed in situ. That is, after forming the ruthenium oxide film in an arbitrary vapor deposition apparatus, the substrate on which the ruthenium oxide film is formed has to be moved to another vapor deposition apparatus to form the ruthenium metal film. Therefore, there is a problem that the process becomes complicated.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] 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.

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

Means for Solving the Problems

[0008] The 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 injecting a ruthenium (Ru)-containing precursor toward a substrate, a step of forming a ruthenium oxide film by injecting an oxygen-containing gas into the ruthenium film, and a step of forming a plasma and exposing the ruthenium oxide film to the plasma.

[0009] When forming the plasma, the plasma may be formed using an oxygen-containing gas.

[0010] The oxygen-containing gas may contain one or more of the following gases: oxygen (O2), ozone (O3), and nitrous oxide (N2O).

[0011] The step of forming the plasma includes a step of forming the plasma using an inert gas in addition to the oxygen-containing gas, wherein the inert gas may include one or more gases from argon (Ar) and helium (He).

[0012] The oxygen content of the ruthenium oxide film exposed to the plasma may be even higher than the oxygen content of the ruthenium oxide film before exposure to the plasma.

[0013] A film formation cycle (CY) including the steps of forming the ruthenium film and forming the ruthenium oxide film. f ) is performed multiple times, and multiple film formation cycles (CY) are carried out. f ) may be performed consecutively.

[0014] The step of exposing the ruthenium oxide film to the plasma is the film formation cycle (CY f This may be done after performing the following multiple times in a row.

[0015] In the step of forming the plasma, the step of forming the plasma using an inert gas in addition to the oxygen-containing gas includes the steps of injecting the oxygen-containing gas and the inert gas toward the ruthenium oxide film, and generating plasma using the injected oxygen-containing gas and the inert gas. When injecting the oxygen-containing gas and the inert gas, the flow rate of the oxygen-containing gas may be even greater than that of the inert gas.

[0016] The aforementioned film formation cycle (CY fWhen injecting an oxygen-containing gas in the device, an inert gas may be injected together, and the inert gas may contain one or more of argon (Ar) and helium (He) gases or a combination of two or more of them.

[0017] The aforementioned film formation cycle (CY f In the process of injecting oxygen-containing gas and inert gas, the flow rate of the oxygen-containing gas may be increased to be even greater than that of the inert gas.

[0018] In the steps of forming the ruthenium film, forming the ruthenium oxide film, and plasma exposure, the substrate temperature may be adjusted to 250°C to 450°C.

[0019] 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 forming a ruthenium oxide film in situ inside the chamber where the ruthenium metal film was formed, either before or after the step of forming the ruthenium metal film, wherein the step of forming the ruthenium oxide film may be performed by the method for forming the ruthenium oxide film.

[0020] In the steps of forming the ruthenium metal film and forming the ruthenium oxide film, the temperature of the substrate may be adjusted to 250°C to 450°C. [Effects of the Invention]

[0021] According to embodiments of the present invention, a ruthenium oxide film with a high oxygen content can be formed. Therefore, the quality of the ruthenium oxide film can be improved, thereby improving the performance of the ruthenium oxide film provided in semiconductor devices. [Brief explanation of the drawing]

[0022] [Figure 1]This figure conceptually illustrates a semiconductor device comprising a ruthenium oxide (RuO2) film formed by a method according to an embodiment of the present invention. [Figure 2] This is a conceptual diagram illustrating a method for forming a ruthenium oxide film according to the method of the first embodiment of the present invention. [Figure 3] (a) to (c) are process diagrams illustrating the vapor deposition step Pf according to the first embodiment of the present invention. [Figure 4] This is a process procedure diagram illustrating the plasma exposure step Pp according to the first embodiment of the present invention. [Figure 5] This is a conceptual diagram illustrating a method for forming a ruthenium oxide film according to a second embodiment of the present invention. [Figure 6] This figure shows the case where a ruthenium oxide (RuO2) film formed by the method according to an embodiment of the present invention is formed on top of a ruthenium metal film. [Figure 7] This figure shows the case where a ruthenium oxide (RuO2) film formed by the method according to the embodiment of the present invention is formed between the substrate and the ruthenium metal film, and on top of the ruthenium metal film. [Modes for carrying out the invention]

[0023] Embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. However, the present invention is not limited in any way to the embodiments disclosed below and can be embodied in a variety of different forms. The following embodiments are provided merely to complete the disclosure of the present invention and to fully inform those in the ordinary skill of the scope of the invention. The drawings may be exaggerated in order to illustrate embodiments of the present invention, and in the drawings, the same reference numerals refer to the same components.

[0024] The present invention relates to a method for forming a ruthenium oxide (RuO2) film that can improve the quality of the ruthenium oxide film. More specifically, the present invention relates to a method for forming a ruthenium oxide film that can form a ruthenium oxide film with an improved oxygen content.

[0025] Figure 1 is a conceptual diagram showing a semiconductor device comprising a ruthenium oxide (RuO2) film formed by a method according to an embodiment of the present invention.

[0026] A semiconductor device comprising a ruthenium oxide (RuO2) film may be, for example, a capacitor. Referring to Figure 1, the capacitor may comprise 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.

[0027] The substrate S may be a semiconductor substrate. More specifically, the substrate S may be a wafer, and may be any one of Si wafers, GaAs wafers, and SiGe wafers. Needless to say, the substrate S may be made of any one of glass, metal, plastic, polymer film, or dielectric material.

[0028] The dielectric film 20 may be formed from a dielectric material containing a metal oxide. More specifically, the dielectric film 20 may be formed from one of the following: ZrO2, Al2O3, TiO2, TaO2, and HfO2.

[0029] The lower conductive film 10 and the upper conductive film 30 are formed from conductive materials. In this case, the lower conductive film 10 may be formed from a ruthenium (Ru) metal film, and the upper conductive film 30 may be formed from a conductive material other than ruthenium (Ru). Needless to say, the upper conductive film 30 may be formed from a ruthenium (Ru) metal film, and the lower conductive film 10 may be formed from a conductive material other than ruthenium (Ru). Furthermore, the lower conductive film 10 and the upper conductive film 30 may also be formed from ruthenium metal films.

[0030] The following describes the case where the underlying conductive film 10 is formed from a ruthenium metal film. For ease of explanation, the underlying conductive film and the ruthenium metal film will be referred to by the same reference numeral "10" in the drawings.

[0031] On the other hand, when an underlying conductive film 10 made of a ruthenium metal film is directly formed on one side of a substrate S, for example, a Si wafer, there is a risk that ruthenium (Ru) contained in the underlying conductive film 10 may migrate or diffuse into the substrate S. This can degrade the performance of the semiconductor device. Therefore, as shown in Figure 1, a ruthenium oxide film 100 is formed between the substrate S and the underlying conductive film 10. In this case, the ruthenium oxide film 100 plays a role in suppressing or preventing the migration of ruthenium (Ru) contained in the underlying conductive film 10 to the substrate S. In other words, the ruthenium oxide film 100 formed between the substrate S and the underlying conductive film 10 is a diffusion barrier film that suppresses or prevents the migration of ruthenium (Ru).

[0032] The ruthenium oxide film 100 formed by the method according to this embodiment may be a diffusion barrier film formed between the substrate S and the underlying conductive film 10, as shown in Figure 1.

[0033] Here, the ruthenium oxide film 100 and the underlying conductive film 10 laminated on the substrate S may be components of the lower electrode. That is, the lower electrode may comprise the ruthenium oxide film 100 formed on the substrate S and the underlying conductive film 10 formed on the ruthenium oxide film 100. The upper conductive film 30 may also be the upper electrode.

[0034] The following describes a method for forming a ruthenium oxide film according to the first embodiment of the present invention, based on Figures 2 to 4. In this description, the formation of a ruthenium oxide film on one side of a substrate S will be used as an example.

[0035] Figure 2 is a conceptual diagram illustrating a method for forming a ruthenium oxide film according to the first embodiment of the present invention. Figures 3(a) to 3(c) show the film formation step P according to the first embodiment of the present invention. fIt is a process flow diagram for explanation. FIG. 4 is a plasma exposure step P according to the first embodiment of the present invention p It is a process flow diagram for explanation.

[0036] In FIG. 2, "on" means injecting a raw material or gas for film formation or generating plasma, and "off" means interrupting or terminating the injection of the raw material or gas, or not generating plasma.

[0037] Referring to FIG. 2, the method for forming a ruthenium oxide film includes a film formation step P for forming a ruthenium oxide (RuO2) film f and a plasma exposure step P for exposing the ruthenium oxide (RuO2) film formed in the film formation step P f to plasma to increase the oxygen content of the ruthenium oxide (RuO2) film. It may include this. p It may be included.

[0038] Hereinafter, for ease of explanation, the ruthenium oxide (RuO2) film formed in the film formation step P f is referred to as "primary ruthenium oxide film 110", and the film formed by exposing the primary ruthenium oxide film 110 formed in the film formation step P f to plasma is referred to as "secondary ruthenium oxide film 100".

[0039] Reflecting this, the method for forming the ruthenium oxide film 100 will be described again as follows. The method for forming the ruthenium oxide film 100 includes a film formation step P for forming the primary ruthenium oxide film 110 f and a plasma exposure step P for exposing the primary ruthenium oxide film 110 to plasma to form a secondary ruthenium oxide film 100 which is a ruthenium oxide film with an increased oxygen content compared to the primary ruthenium oxide film 110. It may be included. p It may be included.

[0040] Film formation step P f and plasma exposure step Pp The process including this can be defined as a single process cycle CY. In other words, "film formation step P f - Plasma exposure step P p The process that proceeds in the order of "[ ]" can be defined as a single process cycle CY. Note that a process cycle CY may be performed multiple times.

[0041] 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 the primary ruthenium oxide film 110 is exposed to plasma. For this reason, both the primary ruthenium oxide film 110 and the secondary ruthenium oxide film 100 can be referred to as ruthenium oxide (RuO2) films. However, there is a difference in the oxygen content between the primary ruthenium oxide film 110 and the secondary ruthenium oxide film 100 formed by the method according to this embodiment. That is, the oxygen content of the primary ruthenium oxide film 100 is even higher than that of the primary ruthenium oxide film 110.

[0042] Furthermore, the secondary ruthenium oxide film 100 is the final product to be formed by the method according to the embodiment. For this reason, the same reference numeral is used for both the final product, the ruthenium oxide film, and the secondary ruthenium oxide film, which are to be formed by the method according to the embodiment. In other words, the reference numeral "100" described later may refer to both the secondary ruthenium oxide film and the final product, the ruthenium oxide film.

[0043] Below, we will first describe the film formation step P based on Figures 2 and 3. f I will explain this.

[0044] Referring to Figures 2 and 3 (a) to (c), the film formation step P f The process includes the steps of forming a ruthenium film 111 by injecting a precursor containing ruthenium (Ru) toward a substrate S (precursor injection step) and forming a primary ruthenium oxide film 110 by injecting an oxygen-containing gas toward the ruthenium film 111.

[0045] Also, film formation step P f The procedure may further include at least one of the following steps: injecting a purge gas between the precursor injection step and the oxygen-containing gas injection step (primary purge step), and injecting a purge gas after the completion of the oxygen-containing gas injection step (secondary purge step). Here, argon (Ar) gas can be used as the purge gas.

[0046] Furthermore, the "precursor injection step - primary purge step - oxygen-containing gas injection step - secondary purge step" is considered one cycle (hereinafter referred to as the film formation cycle CY). f This may also be done. That is, film formation step P f This is the film formation cycle CY f It may also contain the film formation cycle CY f This may include a "precursor injection step - primary purging step - oxygen-containing gas injection step - secondary purging step". And the film formation step P f This involves multiple film formation cycles (CY) f It may also include multiple film formation cycles CY f This may be carried out continuously. Note that the film formation cycle CY f At least one of the primary purge step and the secondary purge step in this process can be omitted.

[0047] The following describes the film formation cycle (CY). f Each step will be explained in more detail.

[0048] In the step of spraying the precursor, a precursor containing (or presenting) ruthenium (Ru) is sprayed toward the substrate S. That is, the precursor containing ruthenium (Ru) is sprayed into the chamber in which the substrate S is placed. Here, as a precursor material containing ruthenium (Ru), for example, ethylcyclopentadienylruthenium ((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 onto one side of the substrate S, and a film containing ruthenium (Ru), i.e., a ruthenium film 111, is formed as shown in Figure 3(a).

[0049] Once the step of injecting the precursor is complete, a purge gas is injected into the chamber containing the substrate S to perform a primary purge. For example, argon (Ar) gas can be used as the purge gas.

[0050] Once the primary purging is complete, an oxygen-containing gas is injected into the chamber containing the substrate S, as shown in Figure 3(b). Here, the oxygen-containing gas may contain, for example, one or more of the following gases: oxygen (O2), ozone (O3), and nitrous oxide (N2O). When the oxygen-containing gas is injected, oxygen (O) penetrates the ruthenium film 111, causing a reaction between the ruthenium film 111 and the oxygen (O). That is, the ruthenium film 111 reacts with the oxygen contained in the oxygen-containing gas and is oxidized. As a result, a primary ruthenium oxide film 110, which is a ruthenium oxide (RuO2) film containing ruthenium (Ru) and oxygen, is formed.

[0051] Film formation step P f The oxygen-containing gas injected in this process is injected to react with the ruthenium film 111, and therefore can be referred to as a "reactant gas." For this reason, the reactant gas can be described as an oxygen-containing gas.

[0052] Once the step of injecting oxygen-containing gas is complete, a purge gas is injected into the chamber containing the substrate S to perform a secondary purge. At this time, the same gas used in the primary purge step can be used as the purge gas; for example, argon (Ar) gas can be used.

[0053] The precursor injection step, primary purging step, oxygen-containing gas injection step, and secondary purging step described above can be performed while the temperature of the substrate S is adjusted to 250°C to 450°C. That is, the film formation cycle CY can be performed while the temperature of the substrate S is adjusted to 250°C to 450°C. f This is carried out. More specifically, the temperature of a susceptor located inside the chamber of the deposition apparatus is adjusted to set the temperature of the substrate S supported on the susceptor to 250°C to 450°C. Then, the film formation cycle CY is performed by injecting a precursor, purge gas, and oxygen-containing gas into the chamber. f This is carried out. As a result, a primary ruthenium oxide film 110, which is a ruthenium oxide film, is formed on the substrate S.

[0054] Next, a film formation cycle CY is performed, which includes the precursor injection step, primary purging step, oxygen-containing gas injection step, and secondary purging step as described above. f This process is repeated multiple times. As a result, as shown in Figure 3(c), multiple primary ruthenium oxide films 110 are stacked on the substrate S.

[0055] In Figure 3(c), multiple film formation cycles (CY) are shown. f In order to distinguish the primary ruthenium oxide film 110 formed by ), multiple primary ruthenium oxide films 110 are shown separately, but the stacked multiple primary ruthenium oxide films 110 may be a single integrated film.

[0056] As described above, when an oxygen-containing gas is injected towards the ruthenium film 111, the ruthenium (Ru) contained in the ruthenium film 111 reacts with oxygen to form a primary ruthenium oxide film 110. However, the primary ruthenium oxide film 110 formed in this way has a low oxygen (O) content. More specifically, the primary ruthenium oxide film 110 has either a low oxygen (O) content compared to the ruthenium (Ru) content, or the ruthenium (Ru) content and oxygen (O) content are equal. In other words, the ratio of ruthenium (Ru) content to oxygen (O) content 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 means that the ruthenium (Ru) content and oxygen (O) content are the same, and a ratio of ruthenium (Ru) content to oxygen (O) content of less than 1:1 means that the oxygen content is even lower than the ruthenium (Ru) content.

[0057] If the oxygen content in the ruthenium oxide film is low, the function of the ruthenium oxide film may be impaired. To explain this in more detail, we will take the example of forming a ruthenium oxide film 100 between the lower conductive film 10 and the substrate S, as explained with reference to Figure 1. Here, the ruthenium oxide film 100 is a diffusion barrier film.

[0058] If the oxygen content in the ruthenium oxide film 100 is low, the ruthenium oxide film 100 may not be able to suppress or prevent the ruthenium (Ru) contained in the underlying conductive film 10 from moving to the substrate S. In other words, the quality of the diffusion barrier film deteriorates due to the low oxygen (O) content in the ruthenium oxide film 100.

[0059] Therefore, in the embodiment, the film formation step P fThe primary ruthenium oxide film 110 formed in the above is exposed to plasma to increase the oxygen (O) content contained in the primary ruthenium oxide film 110. In other words, the primary ruthenium oxide film 110 is exposed to plasma to form a secondary ruthenium oxide film 100 with an increased oxygen content compared to the primary ruthenium oxide film 110. At this time, an oxygen-containing plasma (oxygen plasma) may be formed, and the primary ruthenium oxide film 110 may be exposed to the oxygen plasma to form a secondary ruthenium oxide film 100 with an increased oxygen content.

[0060] The following plasma exposure step P for forming the secondary ruthenium oxide film 100 is performed based on Figures 2 and 4. p I will explain this.

[0061] Referring to Figure 2, plasma exposure step P p This includes the step of injecting an oxygen-containing gas to generate an oxygen-containing plasma. That is, the plasma exposure step P p The procedure includes the steps of injecting an oxygen-containing gas into or towards the chamber in which the substrate S is placed, and generating an oxygen plasma using the injected oxygen-containing gas. The step of generating the oxygen plasma may include the step of supplying a power source for plasma generation. In this case, for example, a radio frequency (RF) power source may be supplied 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 chamber. The oxygen-containing gas may include, for example, one or more gases from among oxygen (O2), ozone (O3), and nitrous oxide (N2O). In this way, by supplying an RF power source and injecting an oxygen-containing gas, it becomes possible to generate an oxygen-containing plasma, i.e., an oxygen plasma, inside the chamber. As a result, as shown in Figure 4, the primary ruthenium oxide film 110 formed on the substrate S is exposed to the oxygen plasma.

[0062] 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, oxygen ions generated during the formation of the oxygen plasma penetrate into the primary ruthenium oxide film 110. In this case, compared to simply injecting an oxygen-containing gas without forming an oxygen plasma, forming an oxygen plasma increases the amount of oxygen that penetrates into the primary ruthenium oxide film 110. This can be explained in more detail as follows: The oxygen contained in the oxygen-containing gas is unionized oxygen. However, when an oxygen-containing gas is injected to generate a plasma, oxygen ions are produced. The rate at which ionized oxygen (oxygen ions) moves toward the primary ruthenium oxide film 110 is even higher than the rate at which unionized oxygen moves toward the primary ruthenium oxide film 110. Therefore, by forming an oxygen plasma after forming the primary ruthenium oxide film 110, the oxygen content contained in the primary ruthenium oxide film 110 can be increased. Furthermore, compared to simply injecting an oxygen-containing gas onto the primary ruthenium oxide film 110 after its formation (without generating an oxygen plasma), forming an oxygen plasma effectively increases the amount of oxygen that penetrates the primary ruthenium oxide film 110.

[0063] Therefore, a secondary ruthenium oxide film 100 can be formed, which is a ruthenium oxide film with an increased oxygen content compared to the primary ruthenium oxide film 110. In this case, the secondary ruthenium oxide film 100 may have an even higher oxygen (O) content than ruthenium (Ru) content. In other words, the ratio of ruthenium (Ru) content to oxygen (O) content may exceed 1:1 (ruthenium content:oxygen content = greater than 1:1). More specifically, the ratio of ruthenium (Ru) content to oxygen (O) content may be 1:2 or greater (ruthenium content:oxygen content = 1:2 or greater).

[0064] Thus, the function of the secondary ruthenium oxide film 100 is improved if the oxygen content in the secondary ruthenium oxide film 100 is high. To explain this in more detail, we will take the case where a ruthenium oxide film is formed between the lower conductive film 10 and the substrate S as explained with reference to Figure 1 as an example. Here, the ruthenium oxide film 100 is a diffusion barrier film, and is a secondary ruthenium oxide film formed through the processes shown in Figures 3(a) and 3(b) and Figure 4. For this reason, the "ruthenium oxide film" shown in Figure 1 will be denoted by the reference numeral "100" in the drawing.

[0065] If the oxygen content of the ruthenium oxide film 100 formed between the underlying conductive film 10 and the substrate S increases, the ruthenium oxide film 100 can effectively suppress or prevent the ruthenium (Ru) contained in the underlying conductive film 10 from moving to the substrate S. In other words, as the oxygen (O) content of the ruthenium oxide film 100 increases, the function of the ruthenium oxide film 100 as a diffusion barrier film improves.

[0066] Then, plasma exposure step P p When performing this procedure, the temperature of the substrate S is as described in the film formation step P above. f The temperature may be the same as in step P. Also, the plasma exposure step P p When performing this, the temperature of the substrate S is determined by the film formation step P f The temperature may be adjusted to have a difference of ±30°C from the point in step P. To give a more specific example, plasma exposure step P p When performing this procedure, the temperature of the substrate S may be adjusted to 250°C to 450°C. In this case, the method for adjusting the temperature of the substrate S is the film formation step P described above. f Since it is similar to [another example], we will omit the explanation.

[0067] Thus, even when the temperature of the substrate S is adjusted to a low temperature of 250°C to 450°C, a ruthenium oxide film with improved oxygen content can be formed. Conventionally, the temperature of the substrate was adjusted to a high temperature of around 800°C to increase the oxygen content of the ruthenium oxide film. In contrast, in this embodiment, even if the substrate S is heated to a low temperature of 250°C to 450°C, a ruthenium oxide film 100 with 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 an oxygen plasma. In other words, by exposing the primary ruthenium oxide film 110 to an oxygen plasma, oxygen can be sufficiently penetrated into the primary ruthenium oxide film 110 without heating the substrate S to a high temperature of around 800°C. Therefore, a ruthenium oxide film 100 containing sufficient oxygen can be formed at a low temperature of 250°C to 450°C.

[0068] Furthermore, the ruthenium metal film 10, which is formed below or above the ruthenium oxide film 100, is formed at a temperature of 250°C to 450°C. Therefore, the ruthenium oxide film 100 and the ruthenium metal film 10 can be formed in situ. That is, after forming the ruthenium oxide film 100 inside the chamber of any deposition apparatus, the ruthenium metal film 10 can be formed inside the same chamber where the ruthenium oxide film 100 was formed. Consequently, when laminating the ruthenium oxide film 100 and the ruthenium metal film 10, the process is simplified and the time required is reduced.

[0069] Figure 5 is a conceptual diagram illustrating a method for forming a ruthenium oxide film according to the method of the second embodiment of the present invention.

[0070] In Figure 5, "on" means injecting raw materials or gases for film formation or generating plasma, while "off" means interrupting or ending the injection of the raw materials or gases, or not generating plasma.

[0071] In the first embodiment described with reference to Figures 2 and 3, the film formation step P f and plasma exposure step P p The injection of an oxygen-containing gas was described in this section. However, the present invention is not limited in any way to the film formation step P. f and plasma exposure step P p When injecting an oxygen-containing gas, an inert gas may be injected together.

[0072] The method for forming a ruthenium oxide film according to the second embodiment of the present invention will be described below with reference to Figure 5. In this case, explanations that overlap with those of the first embodiment will be omitted or simplified.

[0073] Referring to Figure 5, the method for forming a ruthenium oxide film according to the second embodiment involves a film formation step P in which a primary ruthenium oxide film 110 is formed. f Plasma exposure step P: and the primary ruthenium oxide film 110 is exposed to an oxygen-containing plasma to form a secondary ruthenium oxide film 100 with increased oxygen content. p It may include.

[0074] Then, film formation step P f The process includes a precursor injection step of injecting a precursor containing ruthenium (Ru) toward a substrate S to form a ruthenium film 111, and a step of injecting an oxygen-containing gas toward the ruthenium film 111 to form a primary ruthenium oxide film 110, which is a ruthenium oxide film.

[0075] Also, film formation step P f The procedure may further include at least one of the following steps: injecting a purge gas between the precursor injection step and the oxygen-containing gas injection step (primary purge step), and injecting a purge gas after the oxygen-containing gas injection step is completed (secondary purge step). Here, argon (Ar) gas can be used as the purge gas.

[0076] In short, the film formation step P according to the second embodiment f This may include a precursor injection step, a primary purging step, an oxygen-containing gas injection step, and a secondary purging step. The sequence "precursor injection step - primary purging step - oxygen-containing gas injection step - secondary purging step" constitutes one film formation cycle CY. f That is also acceptable.

[0077] In the method according to the second embodiment, the precursor injection step, the primary purge step, and the secondary purge step are performed in the same manner as described in the first embodiment. Therefore, a description of these steps is omitted.

[0078] Film formation step P according to the second embodiment f In the oxygen-containing gas injection step, an inert gas is injected together. That is, when an oxygen-containing gas is injected onto the ruthenium film 111, an inert gas is injected together. In this case, the inert gas may contain one or more of argon (Ar) and helium (He) gases. The reason for injecting the oxygen-containing gas and the inert gas together is the subsequent plasma exposure step P p This is because a plasma is formed using an oxygen-containing gas and an inert gas.

[0079] Film formation step P f The specific reason for injecting oxygen-containing gas and inert gas together in the plasma exposure step P is explained below. p I will explain it first, and then explain it again.

[0080] Referring to Figure 5, plasma exposure step P pThe method includes the steps of injecting an oxygen-containing gas and an inert gas, and generating a plasma using the injected oxygen-containing gas and the inert gas. In this case, the inert gas may contain one or more of argon (Ar) and helium (He). Thus, in the second embodiment, a plasma is generated by injecting an oxygen-containing gas and an inert gas, and the plasma generated at this time is a plasma containing oxygen and an inert element (one or more of Ar and He). For this reason, a plasma containing oxygen and an inert element can be called a mixed plasma.

[0081] 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 further supplied. That is, the step of generating a mixed plasma includes the steps of injecting the oxygen-containing gas and the inert gas into or toward the chamber in which the substrate S is placed, and generating a plasma using the injected oxygen-containing gas and the inert gas. The step of generating the plasma may also include the step of supplying a power source for plasma generation. In this case, for example, a radio frequency (RF) power source may be supplied 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 chamber. The oxygen-containing gas may include, for example, one or more gases from among oxygen (O2), ozone (O3), and nitrous oxide (N2O). The injection unit may inject a mixture of the oxygen-containing gas and the inert gas. Needless to say, separate injection units are provided for injecting oxygen-containing gas and inert gas, and the oxygen-containing gas and inert gas are injected via these separate injection units. In this way, by injecting oxygen-containing gas and inert gas and supplying RF power, a plasma containing oxygen and inert elements, i.e., a mixed plasma, is generated inside the chamber. As a result, the primary ruthenium oxide film 110 formed on the substrate S is exposed to the mixed plasma.

[0082] When the primary ruthenium oxide film 110 is exposed to a mixed plasma, oxygen (O) penetrates into the primary ruthenium oxide film 110. That is, oxygen ions generated when the mixed plasma is generated move into and penetrate the primary ruthenium oxide film 110. At this time, by injecting an inert gas together with the oxygen-containing gas to generate the plasma, oxygen can be penetrated into the primary ruthenium oxide film 110 even more effectively. In other words, the oxygen content can be increased even more effectively to form the secondary ruthenium oxide film 100.

[0083] This is because the density of a mixed plasma formed by injecting both an oxygen-containing gas and an inert gas is even higher than that of a plasma formed by injecting only an oxygen-containing gas. To explain this in more detail, inert elements such as argon (Ar) and helium (He) can be discharged at even lower energies than oxygen. Therefore, the density of a mixed plasma formed by injecting both an oxygen-containing gas and an inert gas (one or more of argon (Ar) and helium (He)) is even higher than that of a plasma formed by injecting only an oxygen-containing gas. In other words, a high-density plasma can be formed by injecting both an oxygen-containing gas and an inert gas and discharging the resulting gas. Furthermore, an increase in plasma density increases the rate at which oxygen ions move into the primary ruthenium oxide film 110, thereby increasing the amount of oxygen ions that penetrate the primary ruthenium oxide film 110 in the same amount of time.

[0084] Therefore, by exposing the primary ruthenium oxide film to a 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 increased more effectively. In other words, compared to forming an oxygen plasma by injecting only an oxygen-containing gas (first embodiment), the amount of oxygen penetrating the primary ruthenium oxide film 110 can be increased more effectively when forming a mixed plasma by injecting an oxygen-containing gas and an inert gas (second embodiment). As a result, the oxygen content can be increased more effectively in the second embodiment compared to the first embodiment when forming the secondary ruthenium oxide film 100. To put it another way, the oxygen content of the ruthenium oxide film 100 can be increased more effectively in the second embodiment compared to the first embodiment.

[0085] Thus, plasma exposure step P p In this step, an inert gas is further injected in addition to the oxygen-containing gas to form a plasma. Therefore, in the second embodiment, the plasma exposure step P p The film formation step P is performed before this step. f In step P, when an oxygen-containing gas is injected, an inert gas is injected together with it. f In the oxygen-containing gas injection step, the oxygen-containing gas and inert gas are injected together. Then, in the film formation step P f and plasma exposure step P p It is preferable to use the same type of inert gas as the inert gas injected in the plasma exposure step P. p This is to ensure stable plasma formation when an oxygen-containing gas and an inert gas are injected to form a plasma. For example, in film formation step P f In the oxygen-containing gas injection step, only the oxygen-containing gas was injected without inert gas. Then, in the subsequent plasma exposure step P pIn this process, an oxygen-containing gas and an inert gas are injected together to form a plasma. In such a case, there is a problem that the plasma energy increases rapidly due to the inert gas. That is, in the film formation step P f In this process, after the chamber is kept free of inert gas, the plasma exposure step P is performed. p When an inert gas is supplied to the inside of a chamber to generate plasma, there is a risk that the plasma energy will rapidly increase due to the inert gas, resulting in the creation of an unstable plasma. This is because argon (Ar) and helium (He) are more easily discharged at lower energies than oxygen.

[0086] Therefore, the film formation step P according to the second embodiment f In this process, the oxygen-containing gas and inert gas are injected together in the oxygen-containing gas injection step. Therefore, in the plasma exposure step P p Plasma can be stably formed in this environment.

[0087] Figure 6 shows the case where the ruthenium oxide (RuO2) film formed by the method according to the embodiment of the present invention is formed on top of the ruthenium metal film. Figure 7 shows the case where the ruthenium oxide (RuO2) film formed by the method according to the embodiment of the present invention is formed between the substrate and the ruthenium metal film, and on top of the ruthenium metal film.

[0088] In Figure 1 described above, the formation of a ruthenium oxide film 100 between the substrate S and the ruthenium metal film 10 was explained. However, the present invention is not limited thereto, and the ruthenium oxide (RuO2) film formed by the method according to the embodiment can be formed at a wide variety of positions.

[0089] For example, as shown in Figure 6, a ruthenium oxide film 100 may be formed on top of the 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 be components of the electrode. That is, the electrode may comprise the ruthenium metal film 10 and the ruthenium oxide film 100 formed on top of the ruthenium metal film 10.

[0090] 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, while the ruthenium oxide film 100 has an even 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 by improving the work function of the electrode, the leakage current can be reduced.

[0091] As another example, as shown in Figure 7, a ruthenium oxide film 100 may be formed on the lower and upper parts of the ruthenium metal film 10, respectively. Here, the ruthenium metal film 10 and the ruthenium oxide films 100 formed on the upper and lower parts of the ruthenium metal film 10 may be components of an electrode. That is, the electrode may comprise the ruthenium metal film 10, the ruthenium oxide film 100 formed on the lower part of the ruthenium metal film 10, and the ruthenium oxide film 100 formed on the upper part of the ruthenium metal film 10.

[0092] Here, the ruthenium oxide film 100 formed beneath the ruthenium metal film 10 acts as a diffusion barrier film that inhibits or prevents the ruthenium (Ru) from the ruthenium metal film 10 from migrating to the substrate S. Furthermore, the ruthenium oxide film 100 formed above the ruthenium metal film 10 can improve the work function of the electrode.

[0093] According to the ruthenium oxide film formation method of this embodiment, a ruthenium oxide film 100 with a high oxygen content can be formed. Specifically, after forming a primary ruthenium oxide film 110 by injecting 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. In other words, the amount of oxygen that penetrates into the primary ruthenium oxide film 110 can be increased. As a result, a secondary ruthenium oxide film 100 with an increased oxygen content compared to the primary ruthenium oxide film 110 can be formed. Therefore, a ruthenium oxide film (RuO2) with an even higher oxygen content than conventional methods can be formed, thereby improving the quality of the ruthenium oxide film 100. In other words, the performance of the ruthenium oxide film 100 provided in semiconductor devices can be improved. [Industrial applicability]

[0094] According to embodiments of the present invention, a ruthenium oxide film with a high oxygen content can be formed. Therefore, the quality of the ruthenium oxide film can be improved, thereby improving the performance of the ruthenium oxide film provided in semiconductor devices.

Claims

1. The process involves the steps of forming a ruthenium film by spraying a ruthenium (Ru)-containing precursor onto a substrate, The steps include: forming a ruthenium oxide film by injecting an oxygen-containing gas onto the ruthenium film; A step of forming a plasma to expose the ruthenium oxide film to the plasma, A method for forming a ruthenium oxide film, including [the specified component].

2. When forming the aforementioned plasma, A method for forming a ruthenium oxide film according to claim 1, comprising forming a plasma using an oxygen-containing gas.

3. The oxygen-containing gas is Oxygen (O ２ ), ozone (O ３ ) and nitrous oxide (N ２ A method for forming a ruthenium oxide film according to claim 2, comprising any one or a combination of two or more gases from O).

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

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

6. A film formation cycle (CY) including the steps of forming the ruthenium film and forming the ruthenium oxide film. ｆ ) is performed multiple times, and multiple film formation cycles (CY) are carried out. ｆ A method for forming a ruthenium oxide film according to claim 1, comprising performing the following steps consecutively.

7. The step of exposing the ruthenium oxide film to the plasma is the film formation cycle (CY ｆ A method for forming a ruthenium oxide film according to claim 6, which is performed after carrying out the following multiple times in succession.

8. The step of forming the plasma by further using an inert gas in addition to the oxygen-containing gas in the step of forming the plasma is: The steps include: spraying an oxygen-containing gas and an inert gas toward the ruthenium oxide film; A step of generating plasma using injected oxygen-containing gas and inert gas, Includes, The method for forming a ruthenium oxide film according to claim 4, wherein when injecting the oxygen-containing gas and the inert gas, the flow rate of the oxygen-containing gas is further increased compared to that of the inert gas.

9. The aforementioned film formation cycle (CY ｆ When injecting an oxygen-containing gas in ) an inert gas is injected together, The method for forming a ruthenium oxide film according to claim 6, wherein the inert gas includes one or more gases selected from argon (Ar) and helium (He).

10. The aforementioned film formation cycle (CY ｆ The method for forming a ruthenium oxide film according to claim 9, wherein when injecting an oxygen-containing gas and an inert gas in the device, the flow rate of the oxygen-containing gas is increased to be even greater than that of the inert gas.

11. A method for forming a ruthenium oxide film according to any one of claims 1 to 10, wherein in the steps of forming the ruthenium film, forming the ruthenium oxide film, and plasma exposure, the temperature of the substrate is adjusted to 250°C to 450°C.

12. The steps include forming a ruthenium metal film on a substrate inside the chamber, The step of forming a ruthenium oxide film in situ inside the chamber in which the ruthenium metal film was formed, either before or after the step of forming the ruthenium metal film, Includes, A method for manufacturing a semiconductor device, wherein the step of forming the ruthenium oxide film is performed by the method for forming a ruthenium oxide film according to any one of claims 1 to 10.

13. The method for manufacturing a semiconductor device according to claim 12, wherein in the steps of forming the ruthenium metal film and forming the ruthenium oxide film, the temperature of the substrate is adjusted to 250°C to 450°C.

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