Method for forming electrode of semiconductor device

Abstract

An electrode forming method according to an embodiment of the present disclosure may include a step of preparing a substrate, a step of spraying a precursor including ruthenium (Ru) on the substrate to form a metal thin film layer, a first processing step of spraying a first processing gas including oxygen (O2) on the substrate, and a second processing step of spraying a second processing gas including oxygen (O2) on the substrate. A purge step of injecting a purge gas after the injection of the first processing gas is stopped; and a second processing step of annealing the metal thin film layer by injecting a second processing gas including at least one of hydrogen gas (H2), argon gas (Ar), and helium gas (He) on the substrate. Accordingly, according to an embodiment of the present disclosure, an electrode from which ligand impurities generated by a precursor including at least one of ruthenium (Ru) and molybdenum (Mo) are removed can be formed. Therefore, an electrode having low resistance can be prepared. Further, when forming an electrode on a substrate having a trench, a step coverage may be improved by reducing a difference between a thickness of a thin film formed on an inner wall where the trench is formed and a thickness of a thin film formed on an upper surface of the substrate.

Description

Technical Field

[0001] The present disclosure relates to a method for forming an electrode of a semiconductor device, and more particularly, to a method for forming an electrode of a semiconductor device with improved electrical performance. Background Art

[0002] In order to improve the electrical performance of a semiconductor device such as a NAND flash, it is necessary to reduce the resistance of the electrode.

[0003] When forming an electrode of a semiconductor device, the electrode is formed by a method of spraying a precursor containing a metal on a substrate and depositing it.

[0004] In addition, the precursor for forming the electrode contains at least one ligand among carbon (C), hydrogen (H), and oxygen (O). However, these ligands act as impurities that increase the resistance of the electrode, and thus there is a problem of deterioration of the electrical performance of the semiconductor device.

[0005] [Related Technical Documents]

[0006] (Patent Document 1) Korean Registered Patent No. 10-0942958. Summary of the Invention

[0007] Technical Problem

[0008] The present disclosure provides a method for forming an electrode of a semiconductor device, which can reduce the resistance of the electrode.

[0009] The present disclosure also provides a method for forming an electrode of a semiconductor device, which can remove impurities.

[0010] Technical Solution

[0011] According to an exemplary embodiment, a method for forming an electrode includes a step of preparing a substrate, a step of spraying a precursor containing ruthenium (Ru) on the substrate to form a metal thin film layer, a first treatment step of spraying a first treatment gas including oxygen (O2) on the substrate, a purge step of spraying a purge gas after stopping 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 including at least one of hydrogen (H2), argon (Ar), and helium (He) on the substrate.

[0012] The method may further include a first plasma treatment step of forming oxygen (O2) plasma on the substrate after the first treatment step.

[0013] The method may further include a first plasma treatment step of forming oxygen (O2) plasma on the substrate before the first treatment step.

[0014] The steps of forming the metal thin film layer, the first processing step, the purging step, and the second processing step can be repeated multiple times.

[0015] The process temperature of the second processing step can be adjusted to be higher than that of the first processing step.

[0016] The pressure in the second processing step can be from 5 Torr to 7 Torr.

[0017] The substrate according to an exemplary embodiment of the present disclosure can include trenches recessed downward from the upper surface of the substrate, and the method of forming an electrode according to an exemplary embodiment of the present disclosure can further include a pretreatment step of exposing the substrate having the metal thin film layer formed thereon to oxygen plasma to convert a part of the metal thin film layer into gaseous metal oxide, thereby etching the metal thin film layer, wherein the pretreatment step can be performed between the first processing step and the purging step, or between the step of forming the metal thin film layer and the first processing step.

[0018] When a part of the metal thin film layer is converted into gaseous metal oxide in the pretreatment step, another part of the metal thin film layer can be converted into solid metal oxide, the second processing gas ejected in the second processing step can include hydrogen (H2), and the second processing step of ejecting the second processing gas including hydrogen (H2) can cause the hydrogen (H2) included in the second processing gas to react with the solid metal oxide contained in the metal thin film layer, thereby reducing the solid metal oxide to metal.

[0019] The second processing step can include a step of generating hydrogen plasma by using the second processing gas including hydrogen (H2).

[0020] According to another exemplary embodiment, a method of forming an electrode includes the steps of preparing a substrate having an indium gallium zinc oxide (IGZO) thin film layer formed on a surface thereof, ejecting a precursor containing ruthenium (Ru) on the IGZO thin film layer to form a metal thin film layer, a first processing step of ejecting a first processing gas including oxygen (O2) on the substrate to remove impurities contained in the metal thin film layer, a purging step of ejecting a purging gas after stopping the ejection of the first processing gas, and a second processing step of ejecting a second processing gas including argon (Ar) on the substrate to anneal the metal thin film layer.

[0021] The method can further include a post-processing step of ejecting a post-processing gas including hydrogen (H2) on the substrate after the second processing step.

[0022] According to another exemplary embodiment, a method of forming an electrode includes a step of preparing a substrate, a first process cycle step including a step of forming a first metal thin film layer on the substrate, and a second process cycle step including a step of forming a second metal thin film layer on the first metal thin film layer. The first process cycle step includes a step of spraying a precursor containing ruthenium (Ru) on the substrate to form the first metal thin film layer, a first treatment step of spraying a first treatment gas including oxygen (O2) on the substrate, a purge step of spraying a purge gas after stopping the spraying of the first treatment gas, and a second treatment step of spraying a second treatment gas including argon (Ar) on the substrate. The second process cycle step includes a step of spraying a precursor containing ruthenium (Ru) on the first metal thin film layer to form the second metal thin film layer, a third treatment step of spraying a third treatment gas including oxygen (O2) on the first metal thin film layer, a purge step of spraying a purge gas after stopping the spraying of the third treatment gas, and a fourth treatment step of spraying a fourth treatment gas including hydrogen (H2) on the first metal thin film layer.

[0023] The fourth treatment step may include a step of including a gas including argon (Ar) before spraying the fourth treatment gas.

[0024] Advantageous Effects

[0025] According to an embodiment of the present disclosure, an electrode from which ligand impurities generated from a precursor containing at least one of ruthenium (Ru) and molybdenum (Mo) are removed can be formed. Therefore, an electrode having a low resistance can be prepared.

[0026] In addition, when forming an electrode on a substrate having grooves, the step coverage can be improved by reducing the difference between the thickness of the thin film formed on the inner wall of the formed groove and the thickness of the thin film formed on the upper surface of the substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a view showing a state in which an electrode is formed on a substrate according to an exemplary embodiment;

[0028] Figure 2 is a conceptual diagram for describing a method of forming an electrode according to an exemplary embodiment;

[0029] Figure 3 is a process diagram conceptually showing a method of forming an electrode according to an exemplary embodiment;

[0030] Figure 4 is a conceptual diagram showing a method of forming a metal thin film layer on a substrate according to another exemplary embodiment;

[0031] Figure 5 is a process diagram conceptually showing a method of forming an electrode according to still another exemplary embodiment;

[0032] Figure 6 is a conceptual diagram for describing a method of forming an electrode according to another exemplary embodiment; and

[0033] Figure 7 is a conceptual diagram for describing a method of forming an electrode according to still another exemplary embodiment. Detailed Description

[0034] Hereinafter, embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and will be implemented in various different forms. The embodiments are only used to make the present disclosure complete and to convey the scope of the present disclosure to those skilled in the art in its entirety. In order to describe the embodiments of the present disclosure, the drawings may be exaggerated, and in the drawings, the same reference numerals indicate the same elements.

[0035] Embodiments of the present disclosure relate to a method of forming an electrode of a semiconductor device, and more particularly, to a method of forming an electrode of a semiconductor device having improved electrical properties. More specifically, embodiments of the present disclosure relate to a method of forming an electrode of a semiconductor device including a method of forming a metal thin film layer having low resistance.

[0036] As a specific example, the semiconductor device may be a NAND flash memory, and the electrode may be a gate of the NAND flash memory. However, the electrode formed by the method according to the embodiment is not limited to the gate and may be various components requiring conductivity, such as a word line of the NAND flash memory. In addition, the electrode formed by the method according to the embodiment is not limited to the NAND flash memory and may be applied to a thin film requiring conductivity in various semiconductor devices.

[0037] [Embodiment 1]

[0038] Figure 1 is a diagram showing a state in which an electrode is formed on a substrate according to an exemplary embodiment.

[0039] Referring to Figure 1 , an electrode 100 may be formed on a substrate S. Here, the substrate S may be a wafer, which may be one of a Si wafer, a gallium arsenide (GaAs) wafer, and a silicon germanium (SiGe) wafer.

[0040] The electrode 100 may be a laminate body formed by stacking a plurality of metal thin film layers 110. In addition, each of the plurality of metal thin film layers 110 may be formed by using a precursor material containing ruthenium (Ru) as a low-resistance metal. Therefore, the electrode 100 may be an electrode containing ruthenium (Ru) or an electrode made of ruthenium (Ru).

[0041] In addition, the metal thin film layer 110 can be formed by using a precursor material containing molybdenum (Mo). Therefore, the electrode 100 can be an electrode containing molybdenum (Mo).

[0042] In addition, the metal thin film layer 110 can be formed by using a precursor material containing ruthenium (Ru) and molybdenum (Mo). Therefore, the electrode 100 can be an electrode containing ruthenium (Ru) and molybdenum (Mo).

[0043] Hereinafter, with reference to Figures 1 to 3 , a method of forming an electrode on a substrate according to an exemplary embodiment will be described.

[0044] Figure 2 is a conceptual diagram for describing a method of forming an electrode according to an exemplary embodiment. Figure 3 is a process diagram conceptually showing a method of forming an electrode according to an exemplary embodiment.

[0045] In Figure 2 , the term "open" may refer to the raw material used in the spraying process, and the term "close" may refer to stopping or terminating the spraying of the raw material.

[0046] With reference to Figure 2 and Figure 3 , a method of forming the electrode 100 includes: a step of spraying a precursor containing at least one of ruthenium (Ru) and molybdenum (Mo) toward the substrate S to form the metal thin film layer 110 (precursor spraying step P pr ); a step of spraying a gas containing oxygen (O2) (hereinafter referred to as the first processing gas) to remove impurities from the metal thin film layer 110 (first processing step P t1 ); and an annealing step of spraying a gas containing at least one of hydrogen (H2), argon (Ar), and helium (He) (hereinafter referred to as the second processing gas) to increase the internal temperature of the chamber in which the process is performed, thereby reducing voids in the metal thin film layer 110 (hereinafter referred to as the second processing step P t2 ).

[0047] In addition, the method of forming the electrode 100 may include a step of spraying a purge gas. That is, the method may include: a first purge step P pr of spraying a purge gas between the precursor spraying step P t1 and the impurity removal step (first processing step P pu1 ); a second purge step P t1 of spraying a purge gas between the impurity removal step (first processing step P t2 ) and the annealing step (second processing step P pu2 ); and a third purge step P t2The third purge step P of ejecting and purging gas after termination pu3 .

[0048] In summary, the method for forming the electrode 100 may include a precursor ejection step P pr , a first purge step P pu1 , an impurity removal step (first treatment step P t1 ), a second purge step P pu2 , an annealing step (second treatment step P t2 ), and a third purge step P pu3 .

[0049] In addition, the precursor ejection step P pr - first purge step P pu1 - impurity removal step (first treatment step P t1 ) - second purge step P pu2 - annealing step (second treatment step P t2 ) - third purge step P pu3 described above can be set as one process cycle CY for forming the metal thin film layer 110. In addition, as Figure 1 shown, the above process cycle CY is repeated multiple times to deposit or stack multiple metal thin film layers 110. Thus, the electrode 100 with multiple metal thin film layers 110 stacked or the electrode 100 of the semiconductor device including 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.

[0050] In the above, it has been described that one process cycle CY includes all the steps in the first purge step Ppu1, the second purge step P pu2 , and the third purge step P pu3 . However, it is not limited thereto, and some of the steps in the first purge step P pu1 , the second purge step P pu2 , and the third purge step P pu3 can be performed, and other steps can be omitted. At this time, preferably, the second purge step P pu2 is performed, and at least one of the first purge step P pu1 and the third purge step P pu3 is omitted.

[0051] In Figure 1 , in order to distinguish the multiple metal thin film layers formed by multiple process cycles CY, each metal thin film layer 110 is shown separately, but the stacked multiple metal thin film layers 110 may be in an integral form.

[0052] In addition, each "step" included in a process cycle CY can be expressed as an "operation". That is to say, the process cycle CY can be described as including a "precursor injection operation P pr - a first purging operation P pu1 - an impurity removal operation (a first treatment operation P t1 ) - a second purging operation P pu2 - an annealing operation (a second treatment operation P t2 ) - a third purging operation P pu3 ".

[0053] Hereinafter, each step included in the process cycle CY will be described in detail. At this time, for the convenience of explanation, the step P of injecting a first treatment gas containing oxygen (O2) to remove impurities t1 will be named and described as the "first treatment step P t1 ". In addition, the step P of injecting a second treatment gas containing at least one of H2, Ar, and He to anneal the metal thin film layer 110 t2 will be named and described as the "second treatment step P t2 ".

[0054] In the precursor injection step P pr , a precursor raw material containing at least one of ruthenium (Ru) and molybdenum (Mo) is injected into the chamber loaded with the substrate S.

[0055] For example, the precursor raw material containing ruthenium (Ru) can be a raw material containing bis(ethylcyclopentadienyl)ruthenium ((EtCp)2Ru). In addition, for example, the precursor raw material containing molybdenum (Mo) can be a raw material containing at least one of molybdenum hexacarbonyl and molybdenum pentachloride. Here, the precursor raw material containing ruthenium (Ru) can be named the "ruthenium (Ru) source", and the precursor raw material containing molybdenum (Mo) can be named the "molybdenum (Mo) source".

[0056] The precursor raw material containing at least one of ruthenium (Ru) and molybdenum (Mo) can be an organic substance. In addition, the precursor raw material can be a solid or a liquid. Therefore, before injecting the solid-phase or liquid-phase precursor, it is heated and converted into a gas, and then the gas-phase precursor is injected onto the substrate S. When the precursor is injected toward the substrate S, the precursor or the metal element contained in the precursor (that is, at least one of ruthenium (Ru) and molybdenum (Mo)) will be adsorbed on the substrate S. Therefore, as Figure 3As shown in (a) in [reference], a metal thin film layer 110 is formed on a substrate S. That is, a metal thin film layer 110 containing at least one of ruthenium (Ru) and molybdenum (Mo) is formed.

[0057] When the precursor injection step Ppr terminates, a purge gas is injected into the chamber and purging is performed (the first purge step P pu1 ). At this time, for example, Ar gas can be used as the purge gas.

[0058] In addition, a precursor raw material containing at least one of ruthenium (Ru) and molybdenum (Mo) may contain at least one ligand of carbon (C), hydrogen (H), and oxygen (O) depending on the type of material. Therefore, the metal thin film layer 110 on which the precursor raw material containing at least one of ruthenium (Ru) and molybdenum (Mo) has been injected and deposited may contain at least one ligand of carbon (C), hydrogen (H), and oxygen (O). In addition, ligands such as carbon (C), hydrogen (H), and oxygen (O) contained in the metal thin film layer 110 act as impurities that increase resistance.

[0059] Therefore, in the embodiment, after injecting the precursor to form the metal thin film layer 110, a step of removing impurities that are at least one ligand among the carbon (C), hydrogen (H), and oxygen (O) impurities from the metal thin film layer 110 is performed, that is, the first treatment step P t1 .

[0060] Hereinafter, the first treatment step P t1 will be described.

[0061] The first treatment step P t1 is a step of removing impurities from the metal thin film layer 110. The first treatment step P t1 includes a step of injecting a first treatment gas including oxygen (O2) into the chamber. Here, the first treatment gas including oxygen (O2) can be, for example, pure oxygen (O2) or air. However, it is not limited thereto, and various gases including oxygen (O2) can be used as the first treatment gas.

[0062] The first treatment step Pt1 can be performed after the precursor injection step P pr and the purge gas injection step (the first purge step P pu1 ) terminate. In other words, the precursor injection step Ppr and the purge gas injection step (the first purge step P pu1 ) are performed in sequence, and the first treatment step P t1 can be performed by injecting the first treatment gas.

[0063] Heat the interior of the chamber in which the substrate S is loaded or in which the process is performed to a temperature above a predetermined temperature. That is, the interior of the chamber can be maintained at a state of keeping the process temperature for forming the metal thin film layer 110, for example, from about 200 °C to about 400 °C. More specifically, the interior of the chamber can be controlled to keep the temperature at about 250 °C to about 300 °C. When the first processing gas is injected into the chamber, the ligands (e.g., carbon (C) ligands) contained in the metal thin film layer 110 react with oxygen (O2). That is, a combustion reaction occurs between the oxygen (O2) and the carbon (C) ligands contained in the first processing gas to separate carbon (C) 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 are broken and detached from the metal thin film layer 110. Therefore, the content of at least one of the ligand impurities of carbon (C), hydrogen (H), and oxygen (O) contained in the metal thin film layer 110 can be reduced, or the ligand impurities can be removed from the metal thin film layer 110.

[0064] As described above, in the first processing step, the temperature inside the chamber is maintained at about 200 °C to about 400 °C, preferably about 250 °C to about 300 °C. Therefore, the combustion reaction between the oxygen (O2) contained in the first processing gas and the ligands can be promoted. That is, the combustion reaction between the oxygen (O2) contained in the first processing gas and the ligands contained in the metal thin film layer 110 can be promoted due to the heat inside the chamber. Therefore, the combustion reaction between the oxygen (O2) contained in the first processing gas and the ligands contained in the metal thin film layer 110 or the precursor can be described as a thermal reaction.

[0065] In the first processing step P t1 After termination, a purge gas is injected into the chamber and purging (the second purge step P pu2 ) is performed. At this time, the purge gas can be the same as the gas used in the first purge step P pu1 , for example, Ar gas can be used.

[0066] The second processing step P t2 can be a process of annealing the metal thin film layer 110 to reduce voids. As shown in (c) of Figure 2 and Figure 3 , the second processing step P t2 includes a step of injecting a second processing gas into the chamber. At this time, the second processing gas can include at least one gas among hydrogen (H2), argon (Ar), and helium (He).

[0067] When injecting a second processing gas into the chamber, the injection is performed such that the pressure inside the chamber is increased compared to the pressure inside the chamber before injecting the second processing gas. At this time, preferably, the pressure inside the chamber is increased to about 5 Torr to about 7 Torr, and the second processing gas is injected for more than 10 seconds.

[0068] The reason for injecting the second processing gas to increase the pressure inside the chamber to about 5 Torr to about 7 Torr is to raise the temperature inside the chamber. For example, before injecting the second processing gas or in the first processing step, the temperature inside the chamber can be about 250 °C to about 300 °C. After that, when injecting the second processing gas to make the pressure inside the chamber become about 5 Torr to about 7 Torr, the temperature inside the chamber can be raised to about 350 °C to about 400 °C. In other words, the pressure increase caused by injecting the second processing gas can raise the temperature inside the chamber. In addition, because the pressure is increased to about 5 Torr to about 7 Torr, the temperature inside the chamber during the second processing step can be controlled to be higher than the temperature inside the chamber during the first processing step.

[0069] Because the temperature inside the chamber is raised, the substrate S or the metal thin film layer 110 deposited on the substrate S can be annealed. Therefore, the grains contained in the metal thin film layer 110 will expand, so that the voids between the grains can be reduced or the voids between the grains can be made smaller. Because the voids are reduced by annealing, the resistance of the metal thin film layer 110 or the electrode 100 can be lowered. That is, a metal thin film layer 110 or an electrode 100 with low resistance can be formed.

[0070] In addition, when injecting the second processing gas, when the injection is performed such that the pressure inside the chamber becomes less than 5 Torr, due to the low temperature inside the chamber, the grains of the metal thin film layer 110 may not expand or may not expand sufficiently. For example, the temperature inside the chamber may be lower than about 350 °C, so that the grains of the metal thin film layer 110 may not expand or may not expand sufficiently. In addition, in order to expand the grains of the metal thin film layer 110, the temperature inside the chamber is controlled to be about 350 °C to about 400 °C, and for this purpose, a pressure of about 7 Torr or less in the chamber is sufficient.

[0071] Therefore, when injecting the second processing gas, the pressure inside the chamber is controlled to be about 5 Torr to about 7 Torr.

[0072] As described above, the second processing gas used in the second processing step includes at least one of hydrogen (H2), argon (Ar), and helium (He). At this time, when a gas including hydrogen (H2) is used as the second processing gas, impurities remaining in the metal thin film layer 110 can be further removed in the second processing step. That is, in the metal thin film layer 110, at least one of the ligand impurities of carbon (C), hydrogen (H), and oxygen (O) that were not removed in the first processing step may remain. The hydrogen (H2) included in the second processing gas can further remove the ligand impurities. In other words, the hydrogen (H2) included in the second processing gas can break and remove at least one ligand bond of carbon (C), hydrogen (H), and oxygen (O) included in the metal thin film layer 110. Therefore, the content of at least one of the ligand impurities of carbon (C), hydrogen (H), and oxygen (O) included in the metal thin film layer 110 can be reduced or removed.

[0073] Second processing step P t2 may include a step of generating plasma. That is, the second processing step P t2 may include a step of generating plasma by using the second processing gas while ejecting the second processing gas. More specifically, the second processing gas is ejected into the chamber or toward the substrate S, and power for generating plasma is supplied. At this time, for example, radio frequency (RF) power is applied to at least one of the chamber, the pedestal on which the substrate S is placed inside the chamber, and the ejection part that ejects the second processing gas into the chamber. Therefore, plasma including at least one of hydrogen (H2), argon (Ar), and helium (He) can be generated inside the chamber.

[0074] The plasma can promote the annealing of the metal thin film layer 110. In other words, compared with the case where the second processing gas is ejected without generating plasma, when plasma is generated while ejecting the second processing gas, the annealing reaction can occur faster to shorten the annealing time.

[0075] After the second processing step P t2 is terminated, a purge gas is ejected into the chamber and purging (third purge step P pu3 ) is performed. At this time, the purge gas can be the same as the gas used in the first purge step P pu1 and the second purge step P pu2 , for example, Ar gas can be used.

[0076] After that, the above-described steps including "precursor ejection step P pr - first purge step P pu1 - first processing step P t1 - second purge step P pu2 - second processing step Pt2 - The third purge step P pu3 ” for a plurality of process cycles CY. Thus, as Figure 1 shown, a plurality of metal thin film layers 110 are formed on the substrate S, and thus an electrode 100 having a predetermined thickness is formed.

[0077] [Embodiment 2]

[0078] Figure 4 is a conceptual diagram showing a method of forming a metal thin film layer on a substrate according to another exemplary embodiment.

[0079] In Figure 4 , the term "on" may refer to the raw materials used in the spraying process or the generation of plasma. In addition, the term "off" may refer to the stop or termination of the raw material spraying or plasma generation.

[0080] The method according to another exemplary embodiment may be the same as the exemplary embodiment in terms of the precursor spraying step P pr , the first purge step P pu1 , the second purge step P pu2 , the third purge step P pu3 and the second processing step P t2 , while it may be different in terms of the first processing step P t1 .

[0081] The first processing step P according to another exemplary embodiment t1 may include a step of generating plasma. That is, as Figure 4 shown, the first processing step P t1 may include a step of spraying a first processing gas and a step of using the sprayed first processing gas to generate oxygen plasma. More specifically, the first processing gas is sprayed into the chamber or toward the substrate S, and power for generating plasma is supplied. At this time, for example, radio frequency (RF) power is applied to at least one of the chamber, the pedestal on which the substrate S is placed inside the chamber, and the spraying unit for spraying gas into the chamber. At this time, preferably, the power applied for plasma generation is controlled to be about 500 W to about 1000 W (about 500 watts to about 1000 watts). Thus, plasma is generated inside the chamber. At this time, since the first processing gas includes oxygen (O2), the plasma generated in the first processing step may be "oxygen plasma".

[0082] When oxygen plasma is generated in the first processing step Pt1, the combustion reaction between the ligand impurities contained in the metal thin film layer 110 and oxygen (O2) can be promoted. That is, since the temperature inside the chamber is maintained at about 250°C to about 300°C, the combustion reaction between the ligand impurities and oxygen (O2) occurs due to the heat inside the chamber, and since oxygen plasma is also generated in addition to the reaction, the combustion reaction between the ligand impurities and oxygen (O2) can be promoted. Therefore, when plasma is generated while injecting the first processing gas, at least one of the impurity removal amount and the impurity removal rate can be increased compared to the case of only injecting the first processing gas. Therefore, the ligand impurities generated from the precursor can be removed more effectively.

[0083] Meanwhile, when the power applied in the first processing step P t1 is less than 500 W, the effect of promoting the combustion reaction by oxygen plasma may not be significant. In addition, when the power applied in the first processing step P t1 is higher than 1000 W, the amount of gaseous or vapor-phase metal oxide such as RuO4 (gas) converted from the metal thin film layer 110 by oxygen plasma may be large, and thus the metal thin film layer 110 may be etched in large amounts. Therefore, when forming the electrode 100 by stacking multiple metal thin film layers 110 through multiple process cycles CY, there may be a problem that it takes a long time to form the electrode 100 to the target thickness. Therefore, in the first processing step P t1 about 500 W to about 1000 W of power is applied to generate oxygen plasma.

[0084] [Embodiment 3]

[0085] Figure 5 is a process diagram conceptually showing a method of forming an electrode according to still another exemplary embodiment. Figure 6 is a conceptual diagram for describing a method of forming an electrode according to still another exemplary embodiment.

[0086] In Figure 6 the term "on" may refer to injecting the raw materials used in the spraying process or generating plasma. In addition, the term "off" may refer to stopping or terminating the raw material injection or plasma generation.

[0087] In the above exemplary embodiment and another exemplary embodiment, forming the electrode 100 by depositing the metal thin film layer 110 on the flat substrate S has been described. However, it is not limited thereto, as Figure 5 shown, the electrode 100 can be formed by depositing the metal thin film layer 110 on the substrate S having the trench TR.

[0088] In addition, as Figure 5As shown in (a) of , when forming the metal thin film layer 110 on the substrate S having the trench TR, an over-hang problem may occur, where the thickness T1 of the metal thin film layer 110 deposited on the upper surface of the substrate S is greater than the thicknesses T2 and T3 of the metal thin film layer 110 deposited on the inner wall surfaces of the formed trench TR. In other words, when the precursor injection step P pr and the first processing step P t1 terminate, the thickness of the metal thin film layer 110 deposited on the substrate S may vary for each position. At this time, as shown in (a) of Figure 5 , the thickness T1 deposited on the upper surface of the substrate S may be different from the thicknesses T2 and T3 deposited on the inner wall surfaces of the formed trench TR. Therefore, when forming the electrode 100 by depositing the metal thin film layer 110 on the substrate S having the trench TR, it is necessary to reduce or prevent over-hang from occurring.

[0089] When depositing the metal thin film layer 110 by a method according to another embodiment, over-hang can be reduced or the occurrence of over-hang can be prevented. That is, by reducing the difference between the thicknesses T2 and T3 of the metal thin film layer 110 deposited on the inner wall surfaces of the formed trench TR and the thickness T1 of the metal thin film layer 110 deposited on the upper surface of the substrate S, the step coverage can be improved.

[0090] Hereinafter, with reference to Figure 5 and Figure 6 , a method of forming an electrode according to another exemplary embodiment will be described.

[0091] With reference to Figure 6 , the method according to another exemplary embodiment may include: a precursor injection step P pr , injecting a precursor containing ruthenium (Ru) and molybdenum (Mo) toward the substrate S to form the metal thin film layer 110; a first processing step Pt1, injecting a first processing gas including oxygen (O2) to remove impurities contained in the metal thin film layer 110; a step P 等离子体-1 , etching a part of the metal thin film layer deposited on the upper surface of the substrate S by generating oxygen plasma while injecting the first processing gas; and a step P t2 , injecting a second processing gas including hydrogen (H2) to reduce the metal oxide (solid) generated in the etching step P 等离子体-1 to a metal.

[0092] Here, since the second processing gas including hydrogen (H2) is injected as in the above exemplary embodiment and another exemplary embodiment, the step of reducing the metal oxide (solid) to a metal is named "the second processing step P t2”. Further, hereinafter, for convenience of explanation, step P of etching a part of the metal thin film layer 110 deposited on the upper surface of the substrate S by generating oxygen plasma while injecting a first processing gas 等离子体-1 is named as “first plasma processing step P 等离子体-1 ” ( Figure 5 in (b) of

[0093] ). Therefore, the method for forming an electrode according to another exemplary embodiment may include a precursor injection step P pr , a first purge step P pu1 , a first processing step P t1 , a first plasma processing step P 等离子体-1 , a second purge step P pu 2, a second processing step P t2 and a third purge step P pu3 .

[0094] Further, in the method for forming an electrode according to another exemplary embodiment, one process cycle CY may include “precursor injection step P pr - first purge step P pu1 - first processing step P t1 - first plasma processing step P 等离子体-1 - second purge step P pu2 - second processing step P t2 - third purge step P pu3 ”, and the process cycle CY may be repeated multiple times.

[0095] Since the precursor injection step P pr and the first purge step P pu1 to the third purge step P pu3 are similar to the precursor injection step P pr and the first purge step P pu1 to the third purge step P pu3 of the exemplary embodiment and another exemplary embodiment, their descriptions will be omitted.

[0096] The above-mentioned first processing step P t1 according to another exemplary embodiment includes a first processing gas injection step and an oxygen plasma generation step. That is, as Figure 4 shown, the first processing step P t1While the first processing gas is being ejected, the oxygen plasma continues to be generated. In other words, while the first processing gas is being ejected, power for generating plasma is applied by applying radio frequency (RF) power to at least one of the susceptor on which the substrate S is placed and the ejection unit that ejects the first processing gas into the chamber. Accordingly, while the first processing gas is being ejected, oxygen (O2) plasma is generated inside the chamber.

[0097] However, the first processing step Pt1 according to still another exemplary embodiment includes the step of ejecting the first processing gas, but does not include the step of generating plasma. In addition, in the first processing step P t1 After the first plasma processing step P 等离子体-1 Includes the step of ejecting the first processing gas and the step of generating plasma by using the first processing gas. In other words, plasma is not generated during the first set period after the start of ejecting the first processing gas (first processing step (P t1 ), and then during the second set period starting from the time after the first set time (first plasma processing step (P 等离子体-1 ), oxygen plasma is generated simultaneously with the ejection of the first processing gas. In other words, power for generating plasma is not applied during the first set period after the start of ejecting the first processing gas (first processing step (P t1 ), and then during the second set period starting from the time after the first set time (first plasma processing step (P 等离子体-1 ), power for generating plasma is applied while ejecting the first processing gas to generate oxygen plasma. The step of generating plasma while ejecting the first processing gas is defined as the first plasma processing step P 等离子体-1 in still another exemplary embodiment.

[0098] Hereinafter, with reference to Figure 5 , the method according to still another exemplary embodiment will be described in more detail.

[0099] For example, when a precursor is ejected onto the substrate S and then the first processing gas including oxygen (O2) is ejected, the metal thin film layer 110 formed on the substrate S may be the same as the metal thin film layer 110 shown in (a) of Figure 5 . That is, the thickness T1 of the metal thin film layer deposited on the upper surface of the substrate S may be greater than the thicknesses T2 and T3 of the metal thin film layers deposited on the inner wall surfaces of the formed trenches TR.

[0100] After the first processing step P t1 for ejecting the first processing gas to remove impurities is terminated, the first plasma processing step P 等离子体-1That is, a first plasma treatment step P is performed to generate plasma by using a first processing gas while injecting the first processing gas. 等离子体-1 For this purpose, while injecting a first processing gas including oxygen (O2) into the chamber, RF power is applied to at least one of the susceptor on which the substrate S is placed and the injection part for injecting gas into the chamber. Therefore, as Figure 5 shown in (b) of [], oxygen plasma is generated inside the chamber.

[0101] 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). In addition, this reaction produces solid metal oxides and gaseous metal oxides. For example, when oxygen plasma is generated inside the chamber, a reaction occurs between ruthenium (Ru) contained in the metal thin film layer 110 and oxygen (O2). Therefore, solid-phase RuO2 (solid) and gaseous-phase RuO4 (gas) are generated (see Figure 5 (b) of []). Among these solid-phase RuO2 and gaseous-phase RuO4, solid-phase RuO2 (solid) remains in the metal thin film layer 110, and gaseous-phase RuO4 (gas) is removed from the metal thin film layer 110 in the gaseous phase. That is, an etching reaction occurs in which a part of the metal thin film layer 110 is converted into a gaseous metal oxide such as RuO4 and removed.

[0102] Etching mainly occurs in the metal thin film layer 110 deposited on the upper surface of the substrate S. This is because when 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 of the formed 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 greater than the etching rate and etching thickness of the metal thin film layer 110 formed on the inner wall surface of the formed trench TR. Therefore, as Figure 5 shown in (c) of [], when the first plasma treatment step P for generating oxygen plasma is performed 等离子体-1 , the difference between the thicknesses T2 and T3 of the metal thin film layer 110 formed on the inner wall surface of the formed trench TR and the thickness T1 of the metal thin film layer 110 formed on the upper surface of the substrate S is reduced.

[0103] The second treatment step P t2 is a process performed after the first plasma treatment step P 等离子体-1 , and is a process for reducing the metal oxide generated in the first plasma treatment step P 等离子体-1 to metal. The second treatment step P t2It includes a step of ejecting a second processing gas including hydrogen (H2). When the second processing gas including hydrogen (H2) is ejected, the metal oxide in the metal thin film layer reacts with hydrogen and is reduced to a metal. For example, as the metal oxide RuO2 (solid) generated in the first plasma processing step P 等离子体-1 reacts with hydrogen (H2) and is reduced to ruthenium (Ru) as a metal.

[0104] In addition, when performing the second processing step P t2 , plasma can be generated. That is, the second processing step P t2 can include a step of ejecting the second processing gas and a step of generating plasma by using the second processing gas. At this time, since the second processing gas includes hydrogen (H2), the plasma generated in the second processing step P t2 can be described as hydrogen plasma. In addition, the hydrogen plasma can promote the reaction of reducing the metal oxide to a metal. Therefore, the time required to reduce the metal oxide to a metal can be shortened.

[0105] As described above, the first plasma processing step P for generating a metal is performed before the second processing step P t2 . Therefore, the first plasma processing step P 等离子体-1 can be named "pretreatment step P 等离子体-1 ", which is performed before the second processing step P 等离子体-1 . t2

[0106] [Embodiment 4]

[0107] Figure 7 is a conceptual diagram for describing a method of forming an electrode according to still another exemplary embodiment.

[0108] In Figure 7 , the term "on" can refer to ejecting the raw materials used in the spraying process or generating plasma. In addition, the term "off" can refer to stopping or terminating the raw material ejection or plasma generation.

[0109] Still another exemplary embodiment is similar to the above-mentioned another exemplary embodiment. However, in still another exemplary embodiment, as Figure 7 shown, the first plasma processing step P 等离子体-1 is performed, and then the first processing step P t1 is performed. That is, according to the process cycle CY of still another exemplary embodiment, it is "precursor ejection step P pr -first purge step P pu1 -first plasma processing step P 等离子体-1 -first processing step P t1 ​- Second purging step P pu2 - Second processing step P t2 - Third purging step P pu3 in the order of

[0110] When performing the third processing step P of forming an oxygen plasma t3 and then performing the first processing step P of ejecting a gas including oxygen (O2) t1 the time required to remove ligand impurities in the first processing step P can be shortened. That is, compared with performing the first processing step P first t1 and then performing the first plasma processing step P t1 in another exemplary embodiment, performing the first plasma processing step P first 等离子体-1 and then performing the first processing step P 等离子体-1 in yet another exemplary embodiment increases the rate of removing ligand impurities. t1

[0111] In the above, another exemplary embodiment and yet another exemplary embodiment are described for forming a metal thin film layer 110 on a substrate S having trenches TR. However, not limited thereto, any one of the above another exemplary embodiment and yet another exemplary embodiment can be applied to form a metal thin film layer 110 on a plane (that is, without trenches TR) of the substrate S.

[0112] In addition, in the above, a metal thin film layer 110 containing at least one of ruthenium (Ru) and molybdenum (Mo) is described as being formed on the upper surface of the substrate S. However, not limited thereto, a predetermined thin film (hereinafter, an underlying layer) can be formed on the upper surface of the substrate S, and a metal thin film layer 110 containing at least one of ruthenium (Ru) and molybdenum (Mo) can be formed on the upper part of the underlying layer. At this time, for example, the underlying layer can be an active layer of a semiconductor device.

[0113] When the underlying layer is indium gallium zinc oxide (IGZO), preferably, a gas not including hydrogen (H2) is used as the second processing gas ejected in the second processing step P t2 This is because when IGZO is exposed to hydrogen (H2), the electrical properties of the underlying layer may deteriorate. Therefore, when the underlying layer is IGZO, preferably, a second processing gas including a gas not including hydrogen (H2) (for example, argon (Ar)) is used to perform the second processing step P t2

[0114] In addition, when the underlying layer is indium gallium zinc oxide (IGZO), in the second processing step P of ejecting a second processing gas including argon (Ar) t2 ​​After termination, a post-treatment step of ejecting a gas including hydrogen (H2) (hereinafter, a post-treatment gas) can be performed.

[0115] In summary, when the underlying layer is indium gallium zinc oxide (IGZO), the process cycle CY can be in the order of "precursor ejection 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 ". Here, the second treatment step P t2 is a step of ejecting a second treatment gas including argon (Ar), and the post-treatment step is a step of ejecting a post-treatment gas including hydrogen (H2). Since the second treatment gas including argon (Ar) is ejected and then the post-treatment gas including hydrogen (H2) (post-treatment step) is ejected, damage to the underlying layer caused by hydrogen (H2) can be suppressed.

[0116] In the above embodiment, the process cycle CY including the same multiple steps has been described as being repeated multiple times. However, it is not limited thereto, and multiple process cycles using different gases can be alternately performed.

[0117] More specifically, the method of forming the electrode 100 can include a first process cycle CY1 and a second process cycle CY2. Here, the first process cycle CY1 can include: a precursor ejection step P pr , ejecting a precursor containing at least one of ruthenium (Ru) and molybdenum (Mo) toward the substrate S to form a first metal thin film layer; a first treatment step P t1 , ejecting a first treatment gas including oxygen (O2) to remove impurities from the first metal thin film layer; a purge step P pu2 , ejecting a purge gas after stopping the ejection of the first treatment gas; and a second treatment step P t2 , ejecting a second treatment gas including argon (Ar). In addition, the second process cycle CY2 can include: a precursor ejection step P pr , ejecting a precursor containing at least one of ruthenium (Ru) and molybdenum (Mo) on the first metal thin film layer to form a second metal thin film layer; a third treatment step P t3 , ejecting a gas including oxygen (O2) (hereinafter, a third treatment gas) to remove impurities from the second metal thin film layer; a purge step P pu2 , ejecting a purge gas after stopping the ejection of the third treatment gas; and a fourth treatment step P t4 , ejecting a fourth treatment gas including hydrogen (H2).

[0118] The third process gas used in the second process cycle CY2 is a gas including oxygen (O2) as described above, and may be the same as the first process gas used in the first process cycle CY1.

[0119] In addition, the second process cycle CY2 can be carried out in the purge step P pu2 and the fourth processing step P t4 The method further includes the step of spraying a gas including argon (Ar).

[0120] As described above, according to the embodiment, an electrode from which ligand impurities generated by a precursor including at least one of ruthenium (Ru) and molybdenum (Mo) are removed can be formed. Therefore, the electrode 100 having low resistance can be prepared.

[0121] In addition, when the electrode 100 is formed on the substrate S having the groove TR, the step coverage can be improved by reducing the difference between the thickness of the metal film layer 110 formed on the inner wall of the groove TR and the thickness of the metal film layer 110 formed on the upper surface of the substrate S.

[0122] Industrial applicability

[0123] According to an embodiment of the present disclosure, an electrode from which ligand impurities generated by a precursor including at least one of ruthenium (Ru) and molybdenum (Mo) are removed can be formed. Therefore, an electrode having low resistance can be prepared.

[0124] Furthermore, when forming an electrode on a substrate having a groove, the step coverage can be improved by reducing the difference between the thickness of a thin film formed on the inner wall of the groove and the thickness of a thin film formed on the upper surface of the substrate.

Claims

1. A method of forming an electrode, the method comprising: a step of preparing a substrate; a step of spraying a precursor containing ruthenium (Ru) on the substrate to form a metal thin film layer; a first treatment step of spraying a first treatment gas including oxygen (O2) on the substrate; a purge step of spraying a purge gas after stopping the spraying of the first treatment gas; and a second treatment step of spraying a second treatment gas including at least one of hydrogen (H2), argon (Ar), and helium (He) on the substrate to anneal the metal thin film layer.

2. The method of forming an electrode according to claim 1, further comprising a first plasma treatment step of forming an oxygen (O2) plasma on the substrate after the first treatment step.

3. The method of forming an electrode according to claim 1, further comprising a first plasma treatment step of forming an oxygen (O2) plasma on the substrate before the first treatment step.

4. The method of forming an electrode according to claim 1, wherein Repeat the steps of forming the metal thin film layer, the first treatment step, the purge step, and the second treatment step multiple times.

5. The method of forming an electrode according to claim 1, wherein, The process temperature of the second treatment step is higher than that of the first treatment step.

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

7. The method for forming an electrode according to claim 1, wherein, The substrate includes a trench recessed downward from the upper surface of the substrate; and The method further comprises a pretreatment step of exposing the substrate having the metal thin film layer formed thereon to oxygen plasma to convert a part of the metal thin film layer into gaseous metal oxide, thereby etching the metal thin film layer, wherein the pretreatment step is performed between the first treatment step and the purge step, or between the step of forming the metal thin film layer and the first treatment step.

8. The method of forming an electrode according to claim 7, wherein when a part of the metal thin film layer is converted into the gaseous metal oxide in the pretreatment step, another part of the metal thin film layer is converted into solid metal oxide; the second treatment gas sprayed in the second treatment step includes hydrogen (H2); and the second treatment step of spraying the second treatment gas including hydrogen (H2) causes the hydrogen (H2) included in the second treatment gas to react with the solid metal oxide included in the metal thin film layer, thereby reducing the solid metal oxide to metal.

9. The method of forming an electrode according to claim 8, wherein, The second treatment step includes a step of generating hydrogen plasma by using the second treatment gas including hydrogen (H2).

10. A method of forming an electrode, the method comprising: a step of preparing a substrate having an indium gallium zinc oxide (IGZO) thin film layer formed on a surface thereof; a step of spraying a precursor containing ruthenium (Ru) on the IGZO thin film layer to form a metal thin film layer; a first treatment step of spraying a first treatment gas including oxygen (O2) on the substrate to remove impurities included in the metal thin film layer; a purge step of spraying a purge gas after stopping the spraying of the first treatment gas; and A second processing step of annealing the metal thin film layer by spraying a second processing gas including argon (Ar) on the substrate.

11. The method of forming an electrode according to claim 10, further comprising a post-processing step of spraying a post-processing gas including hydrogen (H2) on the substrate after the second processing step.

12. A method of forming an electrode, the method comprising: A step of preparing a substrate; A first process cycle step including a step of forming a first metal thin film layer on the substrate; And A second process cycle step including a step of forming a second metal thin film layer on the first metal thin film layer, Wherein, the first process cycle step includes: A step of spraying a precursor containing ruthenium (Ru) on the substrate to form the first metal thin film layer; A first processing step of spraying a first processing gas including oxygen (O2) on the substrate; A purging step of spraying a purging gas after stopping spraying the first processing gas; and A second processing step of spraying a second processing gas including argon (Ar) on the substrate, and The second process cycle step includes: A step of spraying a precursor containing ruthenium (Ru) on the first metal thin film layer to form the second metal thin film layer; A third processing step of spraying a third processing gas including oxygen (O2) on the first metal thin film layer; A purging step of spraying a purging gas after stopping spraying the third processing gas; and A fourth processing step of spraying a fourth processing gas including hydrogen (H2) on the first metal thin film layer.

13. The method of forming an electrode according to claim 12, wherein, The fourth processing step includes a step of including a gas including argon (Ar) before spraying the fourth processing gas.

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