Method for processing thin film and method for manufacturing memory element including the same

Abstract

To provide a method for processing a thin film which can evenly remove a thin film.SOLUTION: The method for processing a thin film according to an embodiment of the present invention includes: a modifier supply step of supplying a modifier containing a halogen group in a chamber containing a substrate and causing a thin film on the substrate to adsorb the modifier; a step of purging the inside of the chamber; a thin film processing step of supplying an etching activator into the inside of the chamber to cause a reaction with the adsorbed modifier, and processing the thin film; and a step of purging the inside of the chamber.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a thin film processing method and a method for manufacturing a memory device including the same, and more particularly to a thin film processing method that can enhance etching characteristics using a modifier and an etching activator, and a method for manufacturing a memory device including the same. [Background technology]

[0002] The main mechanism of conventional top-down patterning is to deposit the desired material in the form of a thin film and then fabricate it into the desired size and shape through isotropic wet etching, anisotropic dry etching, reactive ion etching (RIE), etc. However, as the demand for continuous high performance and low power consumption continues to drive smaller and smaller pattern sizes, innovation beyond the current three-dimensional to multidimensional stacked structures is required, and an etching technology with atomic-level precision that surpasses existing wet / dry etching technologies is required.

[0003] This led to the development of an atomic layer etching method inspired by atomic layer deposition. Conventional atomic layer etching methods involve a modification step in which the surface layer is modified using hydrogen fluoride (HF), which has strong reactivity and is therefore easy to modify, and a removal step in which the modified surface layer is removed by reacting with HF.

[0004] However, while hydrogen fluoride used in conventional atomic layer etching has the advantage of strong reactivity, it has the problem of making it difficult to adjust the etching rate according to the input amount or to etch only a very thin thickness due to the very small diffusion of fluorine atoms. Furthermore, if fluorine atoms penetrate into unwanted areas, they can cause damage and degrade device characteristics. Similarly, the high temperatures used in the process of removing the modified surface layer can also degrade the characteristics of the underlying film.

[0005] Therefore, to realize ideal ALE (Atomic Layer Etch), which is the opposite concept of ALD (Atomic Layer Deposition), it is necessary to develop materials and processes that can maintain a constant etched thickness and control the etching rate through the termination of surface reactions. Summary of the Invention [Problem to be solved by the invention]

[0006] SUMMARY OF THE INVENTION An object of the present invention is to provide a method for forming a thin film that can uniformly remove the thin film, and a method for manufacturing a memory device including the same.

[0007] Another object of the present invention is to provide a method for forming a thin film that can maintain thin film characteristics without leaving impurities, and a method for manufacturing a memory device including the same.

[0008] Further objects of the present invention will become more apparent from the following detailed description. [Means for solving the problem]

[0009] According to one embodiment of the present invention, a thin film processing method includes a modifier supply step of supplying a modifier containing a halogen group into a chamber in which a substrate is placed to adsorb the modifier into a thin film formed on the substrate, a step of purging the inside of the chamber, a thin film processing step of supplying an etching activator into the chamber to react with the adsorbed modifier to process the thin film, and a step of purging the inside of the chamber.

[0010] The modifier can be represented by the following <Chemical Formula 1> or <Chemical Formula 2>. [ka] [ka] In the <Chemical Formula 1> or <Chemical Formula 2>, X1 and X2 are independently hydrogen, chlorine, or a chloroalkyl group having 1 to 5 carbon atoms; R1 to R3 are independently selected from hydrogen, a linear, branched or cyclic alkyl group having 1 to 5 carbon atoms, an aryl group having 6 to 12 carbon atoms, a hydroxy group having 0 to 4 carbon atoms, and an alkoxy group having 0 to 4 carbon atoms.

[0011] The etching activator can be represented by the following <Chemical Formula 3>. [ka] In the <Chemical Formula 3>, n is independently selected from integers of 0 to 8; R1 to R3 are independently a linear, branched, or cyclic alkyl group having 1 to 5 carbon atoms, R4 is selected from hydrogen, a linear, branched or cyclic alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms.

[0012] The etching activator may be any one of O3, O2, and H2O.

[0013] The thin film may have one of Al, Ti, Hf, Nb, Ta, Mo, and W as its central element.

[0014] The thin film may be any one of a metal film, a metal oxide, a metal nitride, and a metal sulfide. In this case, the metal film may include a binary or ternary compound doped with one or more other elements to improve its characteristics.

[0015] The thin film treatment method can be carried out at a temperature of 50 to 700°C.

[0016] According to one embodiment of the present invention, a method for manufacturing a volatile memory device may include the thin film processing method described above.

[0017] According to one embodiment of the present invention, a method for manufacturing a nonvolatile memory device may include the thin film processing method described above. [Effects of the Invention]

[0018] According to one embodiment of the present invention, the thin film can be removed uniformly.

[0019] Furthermore, since the etching activator is uniformly adsorbed on the surface of the material to be etched in atomic layers, the degree of etching can be adjusted more accurately than in conventional etching methods. [Brief explanation of the drawings]

[0020] [Figure 1] 4 is a graph that schematically illustrates a supply period according to an embodiment of the present invention. [Figure 2] 1 is a graph showing a comparison of the thickness of a thin film (Nb2O5) per cycle depending on whether an etching activator is used or not in Example 1 of the present invention. [Figure 3] 1 is a graph showing a comparison of the thickness of a thin film (Ta2O5) per cycle depending on whether an etching activator is used or not in Example 1 of the present invention. [Figure 4] 1 is a graph showing a comparison of the thickness of a thin film (HfO2) per cycle depending on whether an etching activator is used or not in Example 1 of the present invention. [Figure 5] 1 is a graph showing a comparison of the thickness of a thin film (TiO2) per cycle depending on whether an etching activator is used or not in Example 1 of the present invention. [Figure 6] 1 is a graph showing a comparison of the thickness of a thin film (TiN) per cycle depending on whether an etching activator is used or not in Example 1 of the present invention. [Figure 7] 1 is a graph showing a comparison of the thickness of a thin film (TiSiN) per cycle depending on whether an etching activator is used or not in Example 1 of the present invention. [Figure 8] 1 is a graph showing a comparison of the thickness of a thin film (MoN) per cycle depending on whether an etching activator is used or not in Example 1 of the present invention. [Figure 9]1 is a graph showing a comparison of the thickness of a thin film (Mo) per cycle depending on whether an etching activator is used or not in Example 1 of the present invention. [Figure 10] 1 is a graph showing a comparison of the thickness of a thin film (Al2O3) per cycle depending on whether an etching activator is used or not in Example 1 of the present invention. [Figure 11] 10 is a graph showing a comparison of thin film thickness per cycle depending on whether an etching activator is used or not in Example 2 of the present invention. [Figure 12] 10 is a graph showing a comparison of thin film thickness per cycle depending on whether an etching activator is used or not in Example 3 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] Preferred embodiments of the present invention will now be described in more detail with reference to the accompanying Figures 1 to 12. The embodiments of the present invention may be modified in various forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. These embodiments are provided to explain the present invention in more detail to those skilled in the art to which the present invention pertains. Therefore, the shape of each element shown in the drawings may be exaggerated to emphasize a clearer description.

[0022] 1 is a graph showing a schematic diagram of a supply cycle according to an embodiment of the present invention. A substrate is loaded into a process chamber, and the following process conditions are adjusted. The process conditions may include substrate or process chamber temperature, chamber pressure, and gas flow rate, and the temperature is 50 to 700°C.

[0023] The substrate is exposed to the modifier supplied into the chamber, and the modifier is adsorbed into a thin film formed on the surface of the substrate. The thin film can have one of Al, Ti, Hf, Nb, Ta, Mo, or W as its central element, and can be one of a metal film, metal oxide, metal nitride, or metal sulfide. In this case, the metal film can include a binary or ternary compound doped with one or more other elements to improve its characteristics. The modifier supply step is carried out at a temperature of 50 to 700°C.

[0024] Specifically, the modifier can be represented by the following <Chemical Formula 1> or <Chemical Formula 2>. [ka] [ka] In the <Chemical Formula 1> or <Chemical Formula 2>, X1 and X2 are independently hydrogen, chlorine, or a chloroalkyl group having 1 to 5 carbon atoms; R1 to R3 are independently selected from hydrogen, a linear, branched or cyclic alkyl group having 1 to 5 carbon atoms, an aryl group having 6 to 12 carbon atoms, a hydroxy group having 0 to 4 carbon atoms, and an alkoxy group having 0 to 4 carbon atoms.

[0025] Thereafter, a purge gas (eg, an inert gas such as Ar) is supplied into the chamber to remove or purify any unadsorbed modifier or by-products.

[0026] The substrate is then exposed to an etching activator supplied into the chamber, which reacts with the modifier to etch the thin film. The etching activator supply step is carried out at a temperature of 50 to 700°C.

[0027] Specifically, the etching activator can be represented by the following <Chemical Formula 3>. [ka] In the <Chemical Formula 3>, n is independently selected from integers of 0 to 8; R1 to R3 are independently a linear, branched, or cyclic alkyl group having 1 to 5 carbon atoms, R4 is selected from hydrogen, a linear, branched or cyclic alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms.

[0028] The etching activator may be any one of O3, O2, and H2O.

[0029] Thereafter, a purge gas (for example, an inert gas such as Ar) is supplied into the chamber to remove or purify any unadsorbed etching activator or by-products.

[0030] Example 1: Dichloromethyl methyl ether + O Dichloromethyl methyl ether was used as a chlorine modifier and O3 was used as an etching activator to etch Nb2O5, Ta2O5, HfO2, TiO2, TiN, TiSiN (TSN), MoN, and Mo thin films.

[0031] The etching process according to the supply cycle shown in FIG. 1 was as follows, and the following process was performed as one cycle. 1) The process of supplying a modifier into the chamber and adsorbing the modifier onto the substrate. 2) A process of supplying Ar gas into the chamber to remove unadsorbed modifier or by-products. 3) A process in which an etching activator is supplied into the chamber and reacts with the modifier to etch the thin film.

[0032] 2 to 10 are graphs comparing the thin film thickness per cycle with and without the use of an etching activator in Example 1 of the present invention. When only dichloromethyl methyl ether, a chlorine modifier, was used (w / o etching activator), almost no etching occurred in any of the thin films.

[0033] On the other hand, when an etching activator was used (w / etching activator), it was confirmed that the thickness of most thin films decreased linearly. It was confirmed that the surface reaction of the two materials can uniformly etch thin films at the atomic layer level.

[0034] The chlorine modifier forms a modified monolayer through a substitution reaction with the metal element on the top surface or exists on the surface through physical adsorption. When an etching activator containing oxygen is introduced, it forms a metal oxide, i.e., M(Cl). a (O) b This can be interpreted as forming and removing volatile by-products represented by the formula:

[0035] The following Table 1 shows the etching rates of the thin films confirmed in Example 1.

[0036] [Table 1]

[0037] Example 2: Trimethylchloroorthoacetate + O Nb2O5 thin films were etched using trimethyl chloro-orthoacetate as a chlorine modifier and O3 as an etching activator.

[0038] The etching process according to the supply cycle shown in FIG. 1 was as follows, and the following process was performed as one cycle. 1) The process of supplying a modifier into the chamber and adsorbing the modifier onto the substrate. 2) A process of supplying Ar gas into the chamber to remove unadsorbed modifier or by-products. 3) A process in which an etching activator is supplied into the chamber and reacts with the modifier to etch the thin film.

[0039] Figure 11 is a graph comparing the thin film thickness per cycle with and without the use of an etching activator in Example 2 of the present invention. When only trimethylchloroorthoacetate, a chlorine modifier, was used (w / o etching activator), almost no etching occurred in the Nb2O5 thin film.

[0040] On the other hand, when an etching activator was used (w / etching activator), the thickness of the thin film decreased linearly. It was confirmed that the surface reaction of the two materials allowed for uniform etching of the thin film at the atomic layer level.

[0041] Example 3: Trimethylchloroorthoacetate + Trimethylorthoformiate Nb2O5 thin films were etched using trimethylchloro-orthoacetate as a chlorine modifier and trimethyl orthoformate as an etching activator.

[0042] The etching process according to the supply cycle shown in FIG. 1 was as follows, and the following process was performed as one cycle. 1) The process of supplying a modifier into the chamber and adsorbing the modifier onto the substrate. 2) A process of supplying Ar gas into the chamber to remove unadsorbed modifier or by-products. 3) A process in which an etching activator is supplied into the chamber and reacts with the modifier to etch the thin film.

[0043] Figure 12 is a graph comparing the thin film thickness per cycle with and without the use of an etching activator in Example 3 of the present invention. When only trimethylchloroorthoacetate, a chlorine modifier, was used (w / o etching activator), almost no etching occurred in the Nb2O5 thin film.

[0044] On the other hand, when an etching activator was used (w / etching activator), the thickness of the thin film decreased linearly. It was confirmed that the surface reaction of the two materials allowed for uniform etching of the thin film at the atomic layer level.

[0045] The following Table 2 shows the etching rates confirmed in Examples 2 and 3.

[0046] [Table 2]

[0047] Example 4: 1-Chloromethyl ethyl ether + trimethyl orthoacetate TiO2 and Nb2O5 thin films were etched using 1-chloromethyl ethyl ether as a chlorine modifier and trimethyl orthoacetate as an etching activator.

[0048] The etching process according to the supply cycle shown in FIG. 1 was as follows, and the following process was performed as one cycle. 1) The process of supplying a modifier into the chamber and adsorbing the modifier onto the substrate. 2) A process of supplying Ar gas into the chamber to remove unadsorbed modifier or by-products. 3) A process in which an etching activator is supplied into the chamber and reacts with the modifier to etch the thin film.

[0049] The following Table 3 shows the etching rates confirmed in Example 4.

[0050] [Table 3]

[0051] Although the present invention has been described in detail above through the examples, other embodiments are possible, and the technical spirit and scope of the following claims are not limited to the examples.

Claims

1. In the thin film processing method, 1. A thin film processing method, comprising: a modifier supplying step of supplying a modifier containing a halogen group into a chamber in which a substrate is placed, and adsorbing the modifier into a thin film formed on the substrate; a step of purging the chamber; a thin film processing step of supplying an etching activator into the chamber, and reacting with the adsorbed modifier to process the thin film; and a step of purging the chamber.

2. 2. The thin film processing method according to claim 1, wherein the modifier is represented by the following <Chemical Formula 1> or <Chemical Formula 2>. In <Chemical Formula 1> or <Chemical Formula 2>, X1 and X2 are independently hydrogen, chlorine, or a chloroalkyl group having 1 to 5 carbon atoms; R1 to R3 are independently selected from hydrogen, a linear, branched, or cyclic alkyl group having 1 to 5 carbon atoms, an aryl group having 6 to 12 carbon atoms, a hydroxy group having 0 to 4 carbon atoms, and an alkoxy group having 0 to 4 carbon atoms.

3. 2. The method of claim 1, wherein the etching activator is represented by the following formula 3: In the <Chemical Formula 3>, n is independently selected from integers of 0 to 8; R1 to R3 are independently a linear, branched, or cyclic alkyl group having 1 to 5 carbon atoms; R4 is selected from hydrogen, a linear, branched or cyclic alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms.

4. The etching activator is O 3 , O 2 , H 2 2. The thin film processing method according to claim 1, wherein the method is one of the above.

5. 2. The thin film processing method according to claim 1, wherein the thin film has one of Al, Ti, Hf, Nb, Ta, Mo, and W as a central element.

6. 2. The thin film processing method according to claim 1, wherein the thin film is one of a metal film, a metal oxide film, a metal nitride film, and a metal sulfide film.

7. 2. The thin film processing method according to claim 1, wherein the thin film processing method proceeds at a temperature of 50 to 700.degree.

8. A method for manufacturing a volatile memory element, comprising any one of the thin film processing methods according to claims 1 to 7.

9. A method for manufacturing a nonvolatile memory element, comprising any one of the thin film processing methods according to claims 1 to 7.

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