Method for forming electrodes in semiconductor devices

Abstract

An electrode formation method according to an embodiment of the present invention may include the steps of: preparing a substrate; forming a metal thin film layer by spraying a precursor containing ruthenium (Ru) onto the substrate; a first treatment step of spraying a first treatment gas containing oxygen (O2) onto the substrate; a purging step of spraying a purging gas after interrupting the spraying of the first treatment gas; and a second treatment step of annealing the metal thin film layer by spraying a second treatment gas containing at least one of hydrogen (H2), argon (Ar), and helium (He) onto the substrate. Therefore, according to embodiments of the present invention, electrodes can be formed from which ligand impurities originating from a precursor containing at least one of ruthenium (Ru) and molybdenum (Mo) have been removed. Consequently, electrodes with low resistance can be provided. Furthermore, when forming electrodes on a trenched substrate, the difference in film thickness between the thin film formed on the inner wall surface of the trench and the thin film formed on the upper surface of the substrate can be reduced to improve step coverage.

Description

[Technical Field]

[0001] The present invention relates to a method for forming electrodes for semiconductor devices, and more specifically, to a method for forming electrodes for semiconductor devices with improved electrical properties. [Background technology]

[0002] To improve the electrical characteristics of semiconductor devices such as NAND flash memory, it is necessary to lower the resistance of the electrodes.

[0003] When forming electrodes for semiconductor devices, a precursor containing metal is sprayed and deposited onto a substrate.

[0004] On the other hand, the precursors used to form electrodes contain at least one ligand from among C (carbon), H (hydrogen), and O (oxygen). However, these ligands act as impurities that increase the resistance of the electrodes, which leads to a problem in that the electrical properties of the semiconductor device deteriorate. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Korean Registered Patent Publication No. 10-0942958 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The present invention relates to a method for forming electrodes in a semiconductor device that can reduce the resistance of the electrodes.

[0007] The present invention relates to a method for forming electrodes for semiconductor devices that can remove impurities. [Means for solving the problem]

[0008] An electrode formation method according to an embodiment of the present invention may include the steps of: preparing a substrate; forming a thin metal film layer by spraying a precursor containing ruthenium (Ru) onto the substrate; a first treatment step of spraying a first treatment gas containing oxygen (O2) onto the substrate; a purging step of spraying a purging gas after interrupting the spraying of the first treatment gas; and a second treatment step of annealing the thin metal film layer by spraying a second treatment gas containing at least one of hydrogen (H2), argon (Ar), and helium (He) onto the substrate.

[0009] The electrode formation method may include a first plasma treatment step, which is performed after the first treatment step, and in which oxygen (O2) plasma is formed on the substrate.

[0010] The electrode formation method may include a first plasma treatment step, which is performed before the first treatment step, and in which oxygen (O2) plasma is formed on the substrate.

[0011] The steps of forming the metal thin film layer, the first treatment step, the purging step, and the second treatment step may be repeated multiple times.

[0012] The second treatment step may be performed at a higher process temperature than the first treatment step.

[0013] The pressure in the second treatment step may be 5 Torr to 7 Torr.

[0014] A substrate according to an embodiment of the present invention includes a trench recessed downward from the upper surface, and an electrode formation method according to an embodiment of the present invention includes a pre-treatment step of exposing the substrate on which the metal thin film layer is formed to an oxygen plasma to convert a portion of the metal thin film layer into a gas-phase metal oxide and etching the metal thin film layer, the pre-treatment step may be performed between the first treatment step and the purging step, or between the metal thin film layer formation step and the first treatment step.

[0015] In the pre-treatment step, when a portion of the metal thin film layer is converted into a gaseous metal oxide, the other portion of the metal thin film layer is converted into a solid-phase metal oxide, and the second treatment gas injected in the second treatment step contains hydrogen (H2), and the second treatment step of injecting the second treatment gas containing hydrogen (H2) may include a step of reacting the hydrogen (H2) contained in the second treatment gas with the solid-phase metal oxide contained in the metal thin film layer to reduce the solid-phase metal oxide to a metal.

[0016] The second treatment step may include generating a hydrogen plasma using a second treatment gas containing hydrogen (H2).

[0017] An electrode formation method according to an embodiment of the present invention may include the steps of: preparing a substrate on which an IGZO (Indium Gallium Zinc Oxide) thin film layer is formed on one side; forming a metal thin film layer by spraying a precursor containing ruthenium (Ru) onto the IGZO thin film layer; a first treatment step of spraying a first treatment gas containing oxygen (O2) onto the substrate to remove impurities contained in the metal thin film layer; a purging step of spraying a purge gas after interrupting the spraying of the first treatment gas; and a second treatment step of spraying a second treatment gas containing argon (Ar) onto the substrate to anneal the metal thin film layer.

[0018] The electrode formation method may be performed after the second treatment step and may include a post-treatment step in which a post-treatment gas containing hydrogen (H2) is sprayed onto the substrate.

[0019] An electrode formation method according to an embodiment of the present invention includes the steps of preparing a substrate, forming a first process cycle step on the substrate, forming a first metal thin film layer on the substrate, and forming a second metal thin film layer on the first metal thin film layer, wherein the first process cycle includes the steps of forming a first metal thin film layer by spraying a precursor containing ruthenium (Ru) onto the substrate, forming a first metal thin film layer by spraying a first treatment gas containing oxygen (O2) onto the substrate, and purging the substrate by spraying a purge gas after interrupting the spraying of the first treatment gas. The second process cycle may include a second treatment step of injecting a second treatment gas containing argon (Ar) onto a plate, the second process cycle of forming a second metal thin film layer by injecting a precursor containing ruthenium (Ru) onto the first metal thin film layer, a third treatment step of injecting a third treatment gas containing oxygen (O2) onto the first metal thin film layer, a purging step of injecting a purging gas after interrupting the injection of the third treatment gas, and a fourth treatment step of injecting a fourth treatment gas containing hydrogen (H2) onto the first metal thin film layer.

[0020] The fourth treatment step may include injecting a gas containing argon (Ar) before injecting the fourth treatment gas. [Effects of the Invention]

[0021] According to embodiments of the present invention, electrodes can be formed from which ligand impurities originating from a precursor containing at least one of ruthenium (Ru) and molybdenum (Mo) have been removed. Therefore, electrodes with low resistance can be provided.

[0022] Furthermore, when forming electrodes on a trenched substrate, the difference in film thickness between the thin film formed on the inner wall surface of the trench and the thin film formed on the upper surface of the substrate can be reduced to improve step coverage. [Brief explanation of the drawing]

[0023] [Figure 1] This figure shows an electrode according to the first embodiment of the present invention formed on a substrate. [Figure 2] This is a conceptual diagram illustrating a method for forming electrodes according to the method of the first embodiment of the present invention. [Figure 3] This is a conceptual step diagram illustrating a method for forming electrodes according to the method of the first embodiment of the present invention. [Figure 4] This is a conceptual diagram illustrating a method for forming a thin metal film layer on a substrate according to a second embodiment of the present invention. [Figure 5] This is a conceptual step diagram illustrating a method for forming electrodes according to a third embodiment of the present invention. [Figure 6] This is a conceptual diagram illustrating a method for forming electrodes according to a third embodiment of the present invention. [Figure 7] This is a conceptual diagram illustrating a method for forming electrodes according to a fourth embodiment of the present invention. [Modes for carrying out the invention]

[0024] 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. In order to illustrate embodiments of the present invention, the drawings may be exaggerated, and the same reference numerals in the drawings refer to the same components.

[0025] Embodiments of the present invention relate to a method for forming electrodes for semiconductor devices, and more specifically, to a method for forming electrodes for semiconductor devices with improved electrical properties. More specifically, embodiments of the present invention relate to a method for forming electrodes for semiconductor devices that includes a method for forming a low-resistance metal thin film layer.

[0026] As a specific example, the semiconductor element may be a NAND flash, and the electrode may be the gate electrode of the NAND flash. Needless to say, the electrode formed by the method according to the embodiment of the present invention is not limited in any way to a gate electrode, but may be a wide variety of components that require conductivity, for example, the word line of the NAND flash. Furthermore, the electrode formed by the method according to the embodiment of the present invention is not limited in any way to NAND flash, but is applicable to thin films that require conductivity in a wide variety of semiconductor elements.

[0027] [First Embodiment]

[0028] Figure 1 shows an electrode according to the first embodiment of the present invention formed on a substrate.

[0029] Referring to Figure 1, the electrode 100 may be formed on a substrate S. Here, the substrate S may be a wafer, and may be any one of the following: a silicon wafer, a gallium arsenide wafer, or a silicon Germanium wafer.

[0030] The electrode 100 may be a laminate formed by stacking multiple metal thin film layers 110. Each of the multiple metal thin film layers 110 may be formed using a precursor material containing ruthenium (Ru), a metal with low resistance. Therefore, the electrode 100 can be an electrode containing ruthenium (Ru), or an electrode made of ruthenium (Ru).

[0031] Furthermore, the metal thin film layer may be formed using a precursor material containing molybdenum (Mo). Therefore, electrode 100 can be an electrode containing molybdenum (Mo).

[0032] Furthermore, the thin metal film layer may be formed using precursor materials containing ruthenium (Ru) and molybdenum (Mo), and therefore the electrode can be an electrode containing ruthenium (Ru) and molybdenum (Mo).

[0033] The following describes a method for forming electrodes on a substrate according to the first embodiment of the present invention, based on Figures 1 to 3.

[0034] Figure 2 is a conceptual diagram illustrating a method for forming electrodes according to the first embodiment of the present invention. Figure 3 is a conceptual process diagram showing a method for forming electrodes according to the first embodiment of the present invention.

[0035] In Figure 2, "on" may mean injecting the raw material for the process, while "off" may mean interrupting or ending the injection of the raw material.

[0036] Referring to Figures 2 and 3, the method for forming the electrode 100 involves the step of forming a metal thin film layer 110 by injecting a precursor containing at least one of ruthenium (Ru) and molybdenum (Mo) toward the substrate S (precursor injection step P pr ) and a step of removing impurities from the metal thin film layer 110 by injecting a gas containing oxygen (O2) (hereinafter referred to as the first treatment gas) (first treatment step P t1 Annealing step (second treatment step P) involves injecting a gas containing at least one of hydrogen (H2), argon (Ar), and helium (He) (hereinafter referred to as the second treatment gas) to raise the temperature inside the chamber in which the process is carried out, thereby reducing the voids in the metal thin film layer 110. t2 ) includes.

[0037] Also, the method of forming the electrode 100 may include a step of injecting a purge gas. That is, the precursor injection step P pr and a first purge step P t1 of injecting a purge gas between the impurity removal step (the first treatment step P pu1 ), and a second purge step p t1 of injecting a purge gas between the impurity removal step (the first treatment step P t2 ) and the annealing step (the second treatment step P u2 ), and a third purge step P t2 of injecting a purge gas after the annealing step (the second treatment step P pu3 ) is completed.

[0038] In short, the method of forming the electrode 100 described above may include the precursor injection step P pr and the first purge step P pu1 and the impurity removal step (the first treatment step P t1 ) and the second purge step P pu2 and the annealing step (the second treatment step P t2 ) and the third purge step P pu3 .

[0039] Also, as described above, "precursor injection step P pr - first purge step P pu1 - impurity removal step (the first treatment step P t1 )- second purge step P pu2 - annealing step (the second treatment step P t2 )- third purge step P pu3This can be considered as one process cycle (cycle) CY for forming the metal thin film layer 110. Then, the above-described process cycle CY is repeated multiple times to deposit or stack multiple metal thin film layers 110 as shown in Figure 1. In this way, an electrode with multiple metal thin film layers 110 stacked on top of each other, or an electrode 100 of a semiconductor device having multiple metal thin film layers 110 is formed. At this time, the number of repetitions of the process cycle CY can be adjusted according to the target thickness of the electrode 100 to be formed.

[0040] In the above, one process cycle CY consists of the first to third purge steps P pu1 , P pu2 , P pu3 The invention is not limited to the first to third purge steps P. pu1 , P pu2 , P pu3 Only a portion of these steps may be performed, and other parts may be omitted. In this case, the second purge step P pu2 The first and third purge steps P are carried out. pu1 , P pu3 It is preferable to omit at least one of them.

[0041] In Figure 1, each metal thin film layer 110 is shown separately to distinguish between the metal thin film layers formed by multiple process cycles CY; however, the stacked metal thin film layers 110 may be a single integrated unit.

[0042] Furthermore, each "step" included in a single process cycle CY can be rewritten as a "process." That is, process cycle CY can be rewritten as "precursor injection process P." pr - First purging process P pu1 - Impurity removal process (first treatment process P) t1 )-Second purging process P pu2 - Annealing process (second treatment process P) t2 )-Third purging process P pu3 It can be explained that it includes [something].

[0043] The following describes each step included in the process cycle CY in detail. For the sake of clarity, step P involves injecting a first treatment gas containing oxygen (O2) to remove impurities. t1 This is the first treatment step P t1 It is described as "[...]." Step P is also performed by injecting a second treatment gas containing at least one of H2, Ar, and He to anneal the metal thin film layer 110. t2 This is the "second treatment step P" t2 He gives it the name and explains it as such.

[0044] Step P involves injecting a precursor. pr In this process, a precursor material containing at least one of Ru (ruthenium) and molybdenum (Mo) is sprayed into the chamber in which the substrate S is placed.

[0045] As a precursor raw material containing Ru (ruthenium), for example, a raw material containing ethylcyclopentadienylruthenium ((EtCp)2Ru) (bis(ethylcyclopentadienyl)ruthenium) can be used. As a precursor raw material containing molybdenum (Mo), for example, a raw material containing at least one of molybdenum hexacarbonyl or molybdenum pentachloride can be used. Here, the precursor raw material containing ruthenium (Ru) may be named "Ru (ruthenium)-containing source," and the precursor raw material containing molybdenum (Mo) may be named "molybdenum (Mo)-containing source."

[0046] The precursor material containing at least one of Ru (ruthenium) and molybdenum (Mo) may be an organic substance. Furthermore, such a precursor material may be in a solid or liquid phase. Therefore, before injection, the solid or liquid phase precursor is heated to convert it into a gas, and then the gaseous precursor is injected onto the substrate S. When the precursor is injected towards the substrate S, the precursor or the metal elements contained within it, namely Ru (ruthenium) and molybdenum (Mo), are adsorbed onto the substrate S. As a result, a thin metal film layer 110 is formed on the substrate S, as shown in Figure 3(a). That is, a thin metal film layer 110 containing at least one of ruthenium (Ru) and molybdenum (Mo) is formed.

[0047] Precursor injection step P pr Once this is complete, purge gas is injected into the chamber to purge it (first purge step P) pu1 ). In this case, Ar gas can be used as the purge gas, for example.

[0048] On the other hand, a precursor material containing at least one of ruthenium (Ru) and molybdenum (Mo) may contain at least one ligand from among C (carbon), H (hydrogen), and O (oxygen), depending on the type of material. Therefore, the metal thin film layer 110 deposited by spraying a precursor material containing at least one of ruthenium (Ru) and molybdenum (Mo) may contain at least one ligand from among C (carbon), H (hydrogen), and O (oxygen). Ligands such as C (carbon), H (hydrogen), and O (oxygen) contained in the metal thin film layer 110 act as impurities that increase resistance.

[0049] Therefore, in embodiments of the present invention, after injecting a precursor to form a metal thin film layer 110, the first treatment step P is performed, which involves removing an impurity from the metal thin film layer 110 that is at least one ligand among C (carbon), H (hydrogen), and O (oxygen). t1 We will implement this.

[0050] The following is the first treatment step P. t1 I will explain this.

[0051] First treatment step P t1 This is a step to remove impurities from the metal thin film layer 110. t1 The present invention includes the step of injecting a first treatment gas containing oxygen (O2) into the chamber. Here, the first treatment gas containing oxygen (O2) may be, for example, pure oxygen (O2) gas or air. Needless to say, the present invention is not limited thereto, and a wide variety of gases containing oxygen (O2) can be used as the first treatment gas.

[0052] First treatment step P t1 Step P involves injecting the precursor. pr and the step of injecting purge gas (first purge step P pu1 ) may be performed after step P is completed. In other words, step P injecting the precursor. pr and the step of injecting purge gas (first purge step P pu1 After performing the steps in this order, spray the first treatment gas to complete the first treatment step P. t1 You may implement this.

[0053] The chamber in which the substrate S is placed or the chamber in which the process is to be carried out is heated to a predetermined temperature or higher. That is, the inside of the chamber may be maintained at the process temperature for forming the metal thin film layer 110, for example, 200°C to 400°C. More specifically, the temperature inside the chamber may be adjusted to be maintained at 250°C to 300°C. When the first treatment gas is injected into the inside of the chamber, the ligand contained in the metal thin film layer 110, for example, the carbon (C) ligand, reacts with oxygen (O2). That is, a combustion reaction occurs between the oxygen (O2) contained in the first treatment gas and the carbon (C) ligand, causing carbon (C) to detach from the metal thin film layer 110. In other words, the carbon (C) ligand bonds contained in the precursor of the metal thin film layer 110 break and detach from the metal thin film layer 110. This reduces the content of at least one ligand impurity among C (carbon), H (hydrogen), and O (oxygen) contained in the metal thin film layer 110, or removes ligand impurities from the metal thin film layer 110.

[0054] As described above, in the first treatment step, the temperature inside the chamber is maintained at 200°C to 400°C, preferably 250°C to 300°C. This allows the combustion reaction between the oxygen (O2) contained in the injected first treatment gas and the ligand to proceed smoothly. In other words, the heat inside the chamber allows the combustion reaction between the oxygen (O2) contained in the first treatment gas and the ligand contained in the metal thin film layer 110 to proceed smoothly. Therefore, the combustion reaction between the oxygen (O2) contained in the first treatment gas and the ligand contained in the metal thin film layer 110 or the precursor can be explained as a thermal reaction.

[0055] First treatment step P t1 Once this is complete, purge gas is injected into the chamber to purge it (second purge step P) pu2 ). At this time, the purge gas is the first purge step Ppu1 The same type of gas used in the above can be used; for example, Ar gas can be used.

[0056] Second treatment step P t2 This may be a step of annealing the metal thin film layer 110 to reduce voids. t2 The procedure includes the step of injecting a second treatment gas into the chamber, as shown in Figures 2 and 3(c). The second treatment gas may include the step of injecting at least one of hydrogen (H2), argon (Ar), and helium (He).

[0057] When injecting the second treatment gas into the chamber, the injection is carried out in such a way that the pressure inside the chamber is further increased compared to before the injection of the second treatment gas. At this time, it is preferable that the pressure inside the chamber is increased to 5 torr to 7 torr, and that the injection time of the second treatment gas is maintained for 10 seconds or more.

[0058] The reason for injecting the second treatment gas to increase the pressure inside the chamber to 5 torr to 7 torr is to raise the temperature inside the chamber. For example, before injecting the second treatment gas or during the first treatment step, the temperature inside the chamber may be 250°C to 300°C. After this, if the second treatment gas is injected to increase the pressure inside the chamber to 5 torr to 7 torr, the temperature inside the chamber can be raised to 350°C to 400°C. In other words, the temperature inside the chamber can be raised by increasing the pressure due to the injection of the second treatment gas. And as the pressure is increased to 5 torr to 7 torr in this way, the temperature inside the chamber during the second treatment step can be adjusted to be higher than during the first treatment step.

[0059] As the temperature inside the chamber rises, the substrate S or the metal thin film layer 110 deposited on the substrate S becomes annealable. As a result, the grains contained in the metal thin film layer 110 expand, which reduces or shrinks the voids between the grains. As a result of this reduction in voids due to annealing, the resistance of the metal thin film layer 110 or the electrode 100 can be reduced. In other words, it becomes possible to form a metal thin film layer 110 or electrode 100 with low resistance.

[0060] On the other hand, when injecting the second treatment gas, if the pressure inside the chamber is less than 5 torr, the temperature inside the chamber may be too low, causing the grains of the metal thin film layer 110 to not expand or to expand insufficiently. For example, if the temperature inside the chamber is as low as 350°C, the grains of the metal thin film layer 110 may not expand or to expand insufficiently. In order to expand the grains of the metal thin film layer 110, the temperature inside the chamber is adjusted to 350°C to 400°C, and for this purpose, the chamber pressure should be 7 torr or less.

[0061] Therefore, when injecting the second treatment gas, the pressure inside the chamber is adjusted to be between 5 torr and 7 torr.

[0062] As explained above, the second treatment gas used in the second treatment step contains at least one of hydrogen (H2), argon (Ar), and helium (He). When a gas containing hydrogen (H2) is used as the second treatment gas, impurities remaining in the metal thin film layer 110 can be further removed in the second treatment step. That is, the metal thin film layer 110 may contain at least one ligand impurity from C (carbon), H (hydrogen), and O (oxygen) that was not removed in the first treatment step. Such ligand impurities can be further removed by the hydrogen (H2) contained in the second treatment gas. In other words, the hydrogen (H2) contained in the second treatment gas can break and remove at least one ligand bond from C (carbon), H (hydrogen), and O (oxygen) contained in the metal thin film layer 110. This reduces the content of at least one ligand impurity among C (carbon), H (hydrogen), and O (oxygen) contained in the metal thin film layer 110, or removes the ligand impurity.

[0063] Second treatment step P t2 This may include a step of generating plasma, namely the second treatment step P. t2 The procedure may include a step of generating a plasma using a second treatment gas while injecting the second treatment gas. More specifically, the second treatment gas is injected into the chamber or toward the substrate S, and power is supplied for plasma generation. At this time, for example, a radio frequency (RF) power supply is 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 second treatment gas into the chamber. As a result, it becomes possible to generate a plasma containing at least one of hydrogen (H2), argon (Ar), and helium (He) inside the chamber.

[0064] Plasma can promote the annealing of the metal thin film layer 110. In other words, compared to injecting the second treatment gas without generating plasma, generating plasma while injecting the second treatment gas allows the annealing reaction to occur more quickly, thus shortening the time required for annealing.

[0065] Second treatment step P t2 Once this is complete, purge gas is injected into the chamber to purge it (third purge step P) pu3 ). At this time, the purge gas is the first and second purge step P pu1 , P pu2 The same type of gas used in the above can be used; for example, Ar gas can be used.

[0066] Following this, the "precursor injection step P" described above will be performed. pr - First purge step P pu1 -First treatment step P t1 - Second purge step P pu2 - Second treatment step P t2 - Third purge step P pu3 The process cycle CY, which includes the above step, is repeated multiple times. As a result, as shown in Figure 1, multiple metal thin film layers 110 are stacked and formed on the substrate S, thereby forming an electrode 100 of a predetermined thickness.

[0067] [Second Embodiment]

[0068] Figure 4 is a conceptual diagram showing a method for forming a thin metal film layer on a substrate according to the second embodiment of the present invention.

[0069] In Figure 4, "on" may mean injecting raw materials or generating plasma for the process. Conversely, "off" may mean interrupting or ending the injection of raw materials or the generation of plasma.

[0070] The method according to the second embodiment differs from that of the first embodiment in that the precursor injection step P pr , the 1st to 3rd purge steps P pu1 ~P pu3 , the second treatment step P t2 The same applies to the first treatment step P. t1 There are differences.

[0071] First treatment step P according to the second embodiment t1 This may include a step of generating plasma, namely the first treatment step P. t1 As shown in Figure 4, the procedure may include the steps of injecting a first treatment gas and generating an oxygen plasma using the injected first treatment gas. More specifically, the first treatment gas is injected into the chamber or toward the substrate S, and power is supplied for plasma generation. At this time, for example, a radio frequency (RF) power supply is 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 gas into the chamber. At this time, the power supplied for plasma generation is preferably adjusted to 500W to 1000W. As a result, plasma is generated inside the chamber. At this time, since the first treatment gas contains oxygen (O2), the plasma generated in the first treatment step may be "oxygen plasma".

[0072] First treatment step P t1When oxygen plasma is generated, the combustion reaction between ligand impurities contained in the metal thin film layer 110 and oxygen (O2) can be promoted. That is, as the temperature inside the chamber is maintained at 250°C to 300°C, the combustion reaction between ligand impurities and oxygen (O2) occurs due to the heat inside the chamber. In addition to this, the combustion reaction between ligand impurities and oxygen (O2) can be promoted by generating oxygen plasma. Therefore, compared to the case where only the first treatment gas is injected, at least one of the amount and rate of impurity removal can be increased when plasma is generated while injecting the first treatment gas. As a result, ligand impurities originating from precursors can be removed more effectively.

[0073] Meanwhile, the first treatment step P pr If the power supplied is less than 500W, the effect of oxygen plasma in promoting the combustion reaction may be weak. Then, the first treatment step P pr If the power supplied exceeds 1000W, a large amount of the metal thin film layer 110 is converted into a gaseous metal oxide, such as RuO4(gas), by the oxygen plasma, which may lead to excessive etching of the metal thin film layer 110. Therefore, when performing the process cycle CY multiple times to stack multiple metal thin film layers 110 and form the electrode 100, there is a risk that it will take a long time to form the electrode 100 to the target thickness. Consequently, the first treatment step P pr In generating oxygen plasma, 500W to 1000W of power is supplied.

[0074] [Third Embodiment]

[0075] Figure 5 is a conceptual process diagram illustrating a method for forming electrodes according to the third embodiment of the present invention. Figure 6 is a conceptual diagram illustrating a method for forming electrodes according to the third embodiment of the present invention.

[0076] In Figure 6, "on" may mean injecting raw materials for the process or generating plasma. Conversely, "off" may mean interrupting or ending the injection of raw materials or the generation of plasma.

[0077] In the first and second embodiments described above, the electrode 100 was formed by depositing a thin metal film layer 110 onto a planar substrate S. However, the present invention is not limited thereto, and as shown in Figure 5, the electrode 100 may also be formed by depositing a thin metal film layer 110 onto a substrate S with trenches TR.

[0078] On the other hand, when forming a thin metal film layer 110 on a substrate S with a trench TR, as shown in Figure 5(a), there is a problem in that the thickness T1 of the thin metal film layer 110 deposited on the upper surface of the substrate S is even thicker than the thickness T2 and T3 of the thin metal film layer 110 deposited on the inner wall surface forming the trench TR, resulting in an overhang. In other words, step P injecting the precursor pr and the first processing step P t1 When the process is complete, the thickness of the metal thin film layer 110 deposited on the substrate S may vary from position to position. In this case, as shown in Figure 5(a), the thickness T1 deposited on the upper surface of the substrate S may differ from the thicknesses T2 and T3 deposited on the inner wall surface forming the trench TR. Therefore, when depositing the metal thin film layer 110 on the substrate S with the trench TR to form the electrode 100, it is necessary to reduce or prevent overhangs.

[0079] When depositing the metal thin film layer 110 using the method according to the third embodiment, it is possible to reduce or prevent overhangs. Specifically, the difference between the thickness T2 and T3 of the metal thin film layer 110 deposited on the inner wall surface forming the trench TR and the thickness T1 of the metal thin film layer 110 deposited on the upper surface of the substrate S can be reduced, thereby improving step coverage.

[0080] Hereinafter, referring to FIGS. 5 and 6, a method for forming an electrode by the method according to the third embodiment will be described.

[0081] Referring to FIG. 6, the electrode forming method according to the third embodiment includes a precursor injection step P of injecting a precursor containing ruthenium (Ru) and molybdenum (Mo) toward the substrate S to form a metal thin film layer 110. pr a first treatment step P of injecting a first treatment gas containing oxygen (O2) to remove impurities from the metal thin film layer 110. t1 a step P of generating oxygen plasma while injecting the first treatment gas to etch a part of the metal thin film layer deposited on the upper surface of the substrate S. plasma-1 a step P of injecting a second treatment gas containing hydrogen (H2) to plasma-1 reduce the metal oxide (solid) generated in the etching step P to metal. t2 and may include.

[0082] Here, the step of reducing the metal oxide (solid) to metal is the same as the first and second embodiments described above. Since a second treatment gas containing hydrogen (H2) is injected, it is named "the second treatment step P t2 ". And hereinafter, for the sake of easy explanation, the step P of generating plasma while injecting the first treatment gas to etch a part of the metal thin film layer 110 deposited on the upper surface of the substrate S plasma-1 is named "the first plasma treatment step P plasma-1 " (FIG. 5(b)).

[0083] Therefore, the electrode forming method according to the third embodiment includes a precursor injection step P pr a first purge step P pu1 a first treatment step P t1 a first plasma treatment step P plasma-1 a second purge step P pu2And the second treatment step P t2 And the third purge step P pu3 It may include and.

[0084] Furthermore, in the electrode formation method according to the third embodiment, one process cycle CY is "precursor injection step P pr - First purge step P pu1 -First treatment step P t1 - First Plasma Treatment Step P plasma-1 - Second purge step P pu2 - Second treatment step P t2 - Third purge step P pu3 This may include "[...]", and this process cycle CY may be repeated multiple times.

[0085] Precursor injection step P pr And the first to third purge steps P pu1 ~P pu3 Since this is substantially the same as the first and second embodiments, a description thereof will be omitted.

[0086] The first treatment step P according to the second embodiment described above t1 This includes a first treatment gas injection step and an oxygen plasma generation step. That is, as shown in Figure 4, the first treatment step P according to the second embodiment t1 This system continuously generates oxygen plasma while injecting the first treatment gas. In other words, while injecting the first treatment gas, power is supplied for plasma generation, and a radio frequency (RF) power supply is supplied to at least one of the injection units that inject the first treatment gas into the susceptor on which the substrate S is placed and into the chamber. Therefore, oxygen (O2) plasma is generated inside the chamber while injecting the first treatment gas.

[0087] However, the first treatment step P according to the third embodiment t1This includes a step of injecting a first treatment gas, but does not include a step of generating plasma. And a first plasma treatment step P is performed after the first treatment step Pt1. plasma-1 This includes a first treatment injection step and a plasma generation step using a first treatment gas. In other words, after the injection of the first treatment gas begins, plasma is not generated for a first set time (first treatment step P t1 ), and during the period from the time the first set time has elapsed until the second set time, the first treatment gas is injected while simultaneously generating oxygen plasma (first plasma treatment step P plasma-1 ). To explain this in other words, no power is supplied for plasma generation between the start of the injection of the first treatment gas and the first set time (first treatment step P t1 ), and from the time the first set time has elapsed until the second set time, the first treatment gas is injected while power is supplied for plasma generation to generate oxygen plasma (first plasma treatment step P plasma-1 In this way, the step of simultaneously generating plasma while injecting the first treatment gas is, in the third embodiment, the first plasma treatment step P plasma-1 This is how it is defined.

[0088] The method according to the third embodiment will be described in more detail below with reference to Figure 5.

[0089] After the precursor is sprayed onto the substrate S, a first treatment gas containing oxygen (O2) is sprayed. The metal thin film layer 110 formed on the substrate S may be as shown in Figure 5(a), for example. That is, the thickness T1 of the metal thin film layer deposited on the upper surface of the substrate S may be thicker than the thicknesses T2 and T3 of the metal thin film layers 110 deposited on the inner wall surface forming the trench TR.

[0090] First treatment step P involves spraying a first treatment gas to remove impurities. t1 Once that is complete, proceed to the first plasma treatment step P. plasma-1 This is carried out as follows: a first plasma treatment step P in which a plasma is generated using the first treatment gas while injecting the first treatment gas. plasma-1 This process is carried out by injecting a first treatment gas containing oxygen (O2) into the chamber while supplying a radio frequency (RF) power supply to at least one of the susceptor on which the substrate S is placed and the injection unit that injects the gas into the chamber. As a result, an oxygen plasma is generated inside the chamber, as shown in Figure 5(b).

[0091] When oxygen plasma is generated inside the chamber, a reaction occurs between the metal contained in the metal thin film layer 110 and oxygen (O2). This reaction produces a solid-state metal oxide and a gaseous metal oxide. For example, when oxygen plasma is generated inside the chamber, a reaction occurs between the Ru (ruthenium) contained in the metal thin film layer 110 and oxygen (O2). As a result, a solid-state RuO2 (solid) and a gaseous RuO4 (gas) are produced (see Figure 5(b)). Of these, the solid-state RuO2 (solid) remains in the metal thin film layer 110, while the RuO4 (gas) is removed from the metal thin film layer 110 in a gaseous state. In other words, an etching reaction occurs in which a portion of the metal thin film layer 110 is converted to a gaseous metal oxide, such as RuO4, and removed.

[0092] Such etching primarily occurs in the metal thin film layer 110 deposited on the upper surface of the substrate S. This is because, as oxygen plasma is generated on the upper side of the substrate S, the metal thin film layer 110 formed on the upper surface of the substrate S is closer to the oxygen plasma than the metal thin film layer 110 formed on the inner wall surface forming the trench TR. Therefore, when oxygen plasma is generated, the etching rate and etching thickness of the metal thin film layer 110 formed on the upper surface of the substrate are higher than those of the metal thin film layer 110 formed on the inner wall surface forming the trench TR. Consequently, the first plasma treatment step P that generates oxygen plasma... plasma-1 If this is done, as shown in Figure 5(c), the difference between the thickness T2 and T3 of the metal thin film layer 110 formed on the inner wall surface forming the trench TR and the thickness T1 of the metal thin film layer 110 formed on the upper surface of the substrate S will be reduced.

[0093] Second treatment step P t2 This is the first plasma treatment step P plasma-1 A process performed after the first plasma treatment step P plasma-1 This is a process of reducing the metal oxide generated in the process back to the metal. t2 This includes the step of injecting a second treatment gas containing hydrogen (H2). When the second treatment gas containing hydrogen (H2) is injected, the metal oxide in the metal thin film layer reacts with hydrogen and is reduced back to metal. For example, the first plasma treatment step P plasma-1 During this process, the metal oxide RuO2 (Solid) is produced and then reacts with hydrogen (H2) to reduce it to the metal Ru (Ruthenium).

[0094] And then, the second treatment step P t2 Plasma can be generated when performing this procedure. That is, the second treatment step P t2This may include the steps of injecting a second treatment gas and generating plasma using the second treatment gas. In this case, the second treatment gas contains hydrogen (H2), so the second treatment step P t2 The plasma generated in this process can be described as hydrogen plasma. Furthermore, hydrogen plasma can promote the reaction that reduces metal oxides to metals. Therefore, the time required to reduce metal oxides to metals can be shortened.

[0095] As described above, the first plasma treatment step P generates a metal oxide. plasma-1 This is the second treatment step P t2 This is performed before the first plasma treatment step P. plasma-1 This is the second treatment step P t2 The "Pre-treatment Step P" is performed before the main treatment. plasma-1 It is possible to name it "".

[0096] [Fourth Embodiment]

[0097] Figure 7 is a conceptual diagram illustrating a method for forming electrodes according to the fourth embodiment of the present invention.

[0098] In Figure 7, "on" may mean injecting raw materials for the process or generating plasma. Conversely, "off" may mean interrupting or ending the injection of raw materials or the generation of plasma.

[0099] The fourth embodiment is substantially the same as the third embodiment described above. However, in the fourth embodiment, as shown in Figure 7, the first plasma treatment step P plasma-1 After performing the first treatment step P t1 This is carried out. In other words, the process cycle CY according to the fourth embodiment is "precursor injection step P pr - First purge step P pu1- First Plasma Treatment Step P plasma-1 -First treatment step P t1 - Second purge step P pu2 - Second treatment step P t2 - Third purge step P pu3 The process will proceed in the following order:

[0100] Thus, the third treatment step P forms an oxygen plasma. t3 The first treatment step P involves injecting an oxygen (O2) gas after performing the following steps. t1 When performing this, the first treatment step P t1 In this process, the time required to remove ligand impurities can be shortened. That is, the first treatment step P t1 After performing the first step, proceed to the first plasma treatment step P. plasma-1 Compared to the third embodiment in which the first plasma treatment step P is carried out, plasma-1 After performing the first treatment step P t1 In the fourth embodiment, the rate at which ligand impurities are removed is improved.

[0101] In the above, the third and fourth embodiments were described in relation to forming a thin metal film layer 110 on a substrate S with trenches TR. However, the present invention is not limited thereto, and when forming a thin metal film layer 110 on a substrate S without trenches TR, i.e., on a planar substrate S, either one of the third and fourth embodiments described above may be applied.

[0102] In the above, the formation of a metal thin film layer 110 containing at least one of ruthenium (Ru) and molybdenum (Mo) on the upper surface of the substrate S has been described. However, the present invention is not limited thereto, and a predetermined thin film (hereinafter referred to as the underlayer) may be formed on the upper surface of the substrate S, and the metal thin film layer 110 containing at least one of ruthenium (Ru) and molybdenum (Mo) may be formed on top of the underlayer. In this case, the underlayer may be, for example, the active layer of a semiconductor device.

[0103] If the base layer is IGZO (Indium Gallium Zinc Oxide), then the second treatment step P t2 In the second treatment step P, it is preferable to use a gas that does not contain hydrogen (H2) as the second treatment gas that is injected. This is because when IGZO is exposed to hydrogen (H2), there is a risk that the electrical properties of the substrate will deteriorate. Therefore, when the substrate is IGZO, it is preferable to use a second treatment gas that does not contain hydrogen (H2), for example, argon (Ar), in the second treatment step P. t2 It is preferable to carry out this.

[0104] Furthermore, if the substrate is IGZO (Indium Gallium Zinc Oxide), a second treatment step P involves injecting a second treatment gas containing argon (Ar). t2 After the process is completed, a post-treatment step may be performed in which a gas containing hydrogen (H2) (hereinafter referred to as post-treatment gas) is injected.

[0105] In short, if the underlying layer is IGZO (Indium Gallium Zinc Oxide), the process cycle CY is "precursor injection step P pr - First purge step P pu1 -First treatment step P t1 - Second purge step P pu2 - Second treatment step P t2-Post-treatment step- Third purge step P pu3 The steps may be carried out in the following order. Here, the second treatment step P t2 The first step involves injecting a second treatment gas containing argon (Ar), and the second step involves injecting a post-treatment gas containing hydrogen (H2). In this way, since the second treatment gas containing argon (Ar) is injected first, followed by the injection of a post-treatment gas containing hydrogen (H2) (post-treatment step), damage to the substrate film due to hydrogen (H2) can be suppressed.

[0106] In the embodiments described above, the process cycle CY, which includes the same step, was repeatedly performed multiple times. However, the present invention is not limited thereto, and multiple process cycles using different gases may be performed alternately.

[0107] More specifically, the method for forming the electrodes may include a first process cycle CY1 and a second process cycle CY2. Here, the first process cycle CY1 is a precursor injection step P in which a precursor containing at least one of ruthenium (Ru) and molybdenum (Mo) is injected toward a substrate S to form a first metal thin film layer. pr Then, a first treatment step P is performed, in which a first treatment gas containing oxygen (O2) is injected to remove impurities from the first metal thin film layer. t1 Then, after interrupting the injection of the first treatment gas, a purge step P is performed in which a purge gas is injected. pu2 Then, a second treatment step P is performed, injecting a second treatment gas containing argon (Ar). t2 The process may also include the following. The second process cycle CY2 is a precursor injection step P in which a precursor containing at least one of ruthenium (Ru) and molybdenum (Mo) is injected onto the first metal thin film layer to form a second metal thin film layer. prThen, a third treatment step P is performed, in which an oxygen (O2)-containing gas (hereinafter referred to as the third treatment gas) is injected to remove impurities from the second metal thin film layer. t3 Then, after interrupting the injection of the third treatment gas, purge step P injects the purge gas. pu2 Then, a fourth treatment step P is performed, injecting a fourth treatment gas containing hydrogen (H2) onto the second thin metal film layer. t4 This includes,

[0108] The third treatment gas used in the second process cycle CY2 is, as described above, a gas containing oxygen (O2), and may be the same type of gas as the first treatment gas used in the first process cycle CY1.

[0109] Then, the second process cycle CY2 is the purge step P pu2 and the fourth treatment step P t4 The process may further include a step of injecting a gas containing argon (Ar) between the two steps.

[0110] Thus, according to the embodiments of the present invention, it is possible to form an electrode from which ligand impurities originating from a precursor containing at least one of ruthenium (Ru) and molybdenum (Mo) have been removed. Therefore, an electrode 100 with low resistance can be provided.

[0111] Furthermore, when forming electrodes 100 on a substrate S with trenches TR, the step coverage can be improved by reducing the difference between the thickness of the metal thin film layer 110 formed on the inner wall surface of the trenches TR and the thickness of the metal thin film layer 110 formed on the upper surface of the substrate S. [Industrial applicability]

[0112] According to embodiments of the present invention, electrodes can be formed from which ligand impurities originating from a precursor containing at least one of ruthenium (Ru) and molybdenum (Mo) have been removed. Therefore, electrodes with low resistance can be provided.

[0113] Furthermore, when forming electrodes on a substrate with trenches, the step coverage can be improved by reducing the difference between the thickness of the thin film formed on the inner wall surface of the trench and the thickness of the thin film formed on the upper surface of the substrate.

Claims

1. The steps include preparing the circuit board and The steps include: forming a thin metal film layer by spraying a precursor containing ruthenium (Ru) onto the substrate; Oxygen (O) on the substrate ２ A first treatment step involves spraying a first treatment gas containing ) A purging step in which a purge gas is injected after interrupting the injection of the first treatment gas, Hydrogen (H) is placed on the substrate. ２ A second treatment step involves injecting a second treatment gas containing at least one of argon (Ar) and helium (He) to anneal the metal thin film layer, A method for forming electrodes, including the method described above.

2. This is performed after the first treatment step, and oxygen (O) is applied to the substrate. ２ The electrode formation method according to claim 1, comprising a first plasma treatment step of forming a plasma.

3. This is performed before the first treatment step, and oxygen (O) is placed on the substrate. ２ The electrode formation method according to claim 1, comprising a first plasma treatment step of forming a plasma.

4. The electrode formation method according to claim 1, comprising repeating the steps of forming the metal thin film layer, the first treatment step, the purging step, and the second treatment step multiple times.

5. The electrode formation method according to claim 1, wherein the second treatment step has a process temperature even higher than that of the first treatment step.

6. The electrode formation method according to claim 1, wherein the pressure in the second treatment step is 5 Torr to 7 Torr.

7. The substrate includes a trench recessed downwards from the upper surface. The process includes a pretreatment step in which the substrate on which the metal thin film layer is formed is exposed to an oxygen plasma to convert a portion of the metal thin film layer into a gas-phase metal oxide, thereby etching the metal thin film layer. The electrode formation method according to claim 1, wherein the pre-treatment step is performed between the first treatment step and the purging step, or between the metal thin film layer formation step and the first treatment step.

8. In the aforementioned pretreatment step, when a portion of the metal thin film layer is converted into a gas-phase metal oxide, the other portion of the metal thin film layer is converted into a solid-phase metal oxide. The second treatment gas sprayed in the second treatment step is hydrogen (H ２ ) including, Hydrogen (H ２ The second treatment step involves injecting a second treatment gas containing ) and the hydrogen (H) contained in the second treatment gas. ２ The electrode formation method according to claim 7, comprising the step of reacting with a solid-phase metal oxide contained in the metal thin film layer to reduce the solid-phase metal oxide to a metal.

9. The second treatment step is hydrogen (H ２ The electrode forming method according to claim 8, comprising the step of generating a hydrogen plasma using a second treatment gas containing ).

10. The steps include: preparing a substrate on which a thin film layer of IGZO (Indium Gallium Zinc Oxide) is formed on one side; The steps include: forming a metal thin film layer by spraying a ruthenium (Ru)-containing precursor onto the IGZO thin film layer; Inject a first treatment gas containing oxygen (O ２ ) into the substrate to remove impurities contained in the metal thin film layer, the first treatment step; A purging step in which a purge gas is injected after interrupting the injection of the first treatment gas, A second treatment step involves injecting a second treatment gas containing argon (Ar) onto the substrate to anneal the thin metal film layer. A method for forming electrodes, including the method described above.

11. This is performed after the second treatment step, and hydrogen (H) is applied to the substrate. ２ The electrode forming method according to claim 10, comprising a post-treatment step of injecting a post-treatment gas containing ).

12. The steps include preparing the circuit board and A first process cycle step including the step of forming a first metal thin film layer on the substrate, A second process cycle step including the step of forming a second metal thin film layer on the first metal thin film layer, Includes, The first process cycle described above is: The steps include: forming a first metal thin film layer by spraying a precursor containing ruthenium (Ru) onto the substrate; Oxygen (O) on the substrate ２ A first treatment step involves spraying a first treatment gas containing ) A purging step in which a purge gas is injected after interrupting the injection of the first treatment gas, A second treatment step involves spraying a second treatment gas containing argon (Ar) onto the substrate, Includes, The second process cycle is, The steps include: forming a second metal thin film layer by injecting a ruthenium (Ru)-containing precursor onto the first metal thin film layer; Oxygen (O) is placed on the first metal thin film layer. ２ A third treatment step involves spraying a third treatment gas containing ) A purge step in which a purge gas is injected after interrupting the injection of the third treatment gas, Hydrogen (H) is placed on the first metal thin film layer. ２ A fourth treatment step involves spraying a fourth treatment gas containing ) A method for forming electrodes, including the method described above.

13. The electrode forming method according to claim 12, wherein the fourth treatment step includes injecting a gas containing argon (Ar) before injecting the fourth treatment gas.

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