Thin film processing method and storage device manufacturing method
Through the combination method of halogen-containing modifier and etching active agent, the problem of etching rate control and the problem of reducing film characteristics in traditional etching methods is solved, and uniform etching and thickness control of the film is realized, which is suitable for etching of multi-dimensional laminated structures.
Patent Information
- Application Number
- CN202510123321.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-02-23
- Filing Date
- 2025-01-26
- Publication Date
- 2025-07-25
AI Technical Summary
The prior art is difficult to achieve high-precision etch control at the atomic level, and traditional etching methods may lead to reduced film characteristics and impurity residues.
The film is treated by a combination of halogen-containing modifier and etching active agent, and combined with the inert gas purification step, uniform etching and thickness control of the film is achieved.
It realizes uniform removal of the film, accurately controls the degree of etching, avoids the reduction of film characteristics and impurities residues, and is suitable for the etching requirements of multi-dimensional laminated structures.
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Figure CN120376453A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a thin film processing method and a method for manufacturing a storage device including the thin film processing method. More specifically, it relates to a thin film processing method that can promote etching characteristics using a modifier and an etching activator, and a method for manufacturing a storage device including the thin film processing method. Background Art
[0002] In a conventional top-down patterning mechanism, after depositing a desired substance as a thin film, it is generally formed into a desired size and shape by isotropic wet etching, anisotropic dry etching, reactive ion etching (RIE), etc. However, due to the continuous requirements for high performance and low power consumption, as the pattern size becomes more and more miniaturized, innovation in multi-dimensional stacked structures exceeding three-dimensional structures is required, and an etching technique with high precision at the atomic level beyond existing wet / dry etching techniques is needed.
[0003] Accordingly, an atomic layer etching method inspired by atomic layer deposition has been developed. The conventional atomic layer etching method is implemented through a modification step and a removal step. In the modification step, hydrogen fluoride (HF), which can be easily modified due to its strong reactivity, is used to modify the surface layer. In the removal step, the modified surface layer is removed by reacting with the modified surface layer.
[0004] However, although hydrogen fluoride used in the conventional atomic layer etching method has the advantage of strong reactivity, due to the diffusion of very small fluorine atoms, there are problems such as difficulty in controlling the etching rate according to the input amount or only etching a very thin thickness. In addition, if fluorine atoms enter an undesired area, it may cause damage and reduce the characteristics during that period, and the high temperature during the process of removing the modified surface layer will also cause a reduction in the characteristics of the bottom film.
[0005] Therefore, to implement an ideal AL E (atomic layer etching) equivalent to the opposite concept of ALD (atomic layer deposition), materials and processes that can maintain a certain etching thickness and control the etching rate through the end of the surface reaction need to be developed. Summary of the Invention
[0006] An object of the present invention is to provide a thin film processing method capable of uniformly removing a thin film and a method for manufacturing a storage device including the thin film processing method.
[0007] Another object of the present invention is to provide a thin film processing method that can easily adjust the thickness of a thin film through a low etching rate and a method for manufacturing a storage device including the thin film processing method.
[0008] In addition, another object of the present invention is to provide a thin film processing method that can maintain the characteristics of a thin film without leaving impurities and a method for manufacturing a storage device including the thin film processing method.
[0009] Other objects of the present invention will become clearer in the following detailed description.
[0010] The thin film treatment method of the present invention includes: a step of supplying a halogen-based modifier into a cavity where a substrate is placed to adsorb the modifier onto a thin film formed on the substrate; a step of purifying the interior of the cavity; a step of supplying an etching activator into the cavity to react the etching activator with the adsorbed modifier and treat the thin film; and a step of purifying the interior of the cavity.
[0011] The modifier can be represented by the following Chemical Formula 1 or Chemical Formula 2: <Chemical Formula 1> <Chemical Formula 2> In Chemical Formula 1 or Chemical Formula 2, X1 and X2 are each hydrogen, a chlorine element, or a chloroalkyl group having 1 to 5 carbon atoms, and R1 to R3 are each selected from hydrogen, a straight-chain alkyl group, a branched-chain alkyl group, or a cycloalkyl group having 1 to 5 carbon atoms, an aryl group having 6 to 12 carbon atoms, a hydroxyl group having 0 to 4 carbon atoms, or an alkoxy group having 0 to 4 carbon atoms.
[0012] The etching activator can be represented by the following Chemical Formula 3: <Chemical Formula 3> In Chemical Formula 3, n is each selected from integers of 0 to 8, R1 to R3 are each a straight-chain alkyl group, a branched-chain alkyl group, or a cycloalkyl group having 1 to 5 carbon atoms, and R4 is selected from hydrogen, a straight-chain alkyl group, a branched-chain alkyl group, or a cycloalkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms.
[0013] The etching activator can be one of O3, O2, or H2O.
[0014] The thin film can have Al, Ti, Hf, Nb, Ta, Mo, or W as a central element.
[0015] The thin film can be one of a metal film, a metal oxide, a metal nitride, or a metal sulfide. Here, the metal film can include a binary compound or a ternary compound doped with one or more other elements for improving characteristics.
[0016] The thin film treatment method can be implemented at 50°C to 700°C.
[0017] The manufacturing method of the volatile storage device of the present invention can include the above-described thin film treatment method.
[0018] The manufacturing method of the non-volatile storage device of the present invention may include the thin film processing method described above. Description of the Drawings
[0019] Figure 1 It is a diagram schematically showing the supply cycle based on an embodiment of the present invention.
[0020] Figures 2 to 10 It is a diagram comparing the thin film thickness of each cycle according to whether an etching activator is used in Embodiment 1 of the present invention.
[0021] Figure 11 It is a diagram comparing the thin film thickness of each cycle according to whether an etching activator is used in Embodiment 2 of the present invention.
[0022] Figure 12 It is a diagram comparing the thin film thickness of each cycle according to whether an etching activator is used in Embodiment 3 of the present invention. Detailed Description of the Invention
[0023] Next, in conjunction with Figures 1 to 12 , the embodiments of the present invention will be described. The embodiments of the present invention can be varied in various forms, and the scope of the present invention should not be construed as being limited to the embodiments described below.
[0024] Figure 1 It is a diagram schematically showing the supply cycle based on an embodiment of the present invention. The substrate is loaded into the process chamber, and subsequent ALD process conditions are adjusted. The process conditions may include the temperature of the substrate or the process chamber, the temperature inside the process chamber, and the gas flow rate, and the temperature is 50°C to 700°C.
[0025] The substrate is exposed to the modifier supplied inside the chamber, and the modifier is adsorbed onto the thin film formed on the surface of the substrate. The thin film may have Al, Ti, Hf, Nb, Ta, Mo, or W as a central element, and the thin film may be one of a metal film, a metal oxide, a metal nitride, or a metal sulfide. Here, the metal film may include a binary compound or a ternary compound doped with one or more other elements for improving characteristics. The modifier is supplied at 50°C to 700°C.
[0026] Specifically, the modifier may be represented by the following Chemical Formula 1 or Chemical Formula 2: <Chemical Formula 1> <Chemical Formula 2> In Chemical Formula 1 or Chemical Formula 2, X1 and X2 are each hydrogen, a chlorine element, or a chloroalkyl group having 1 to 5 carbon atoms, and R1 to R3 are each selected from hydrogen, a straight-chain alkyl group, a branched-chain alkyl group, or a cycloalkyl group having 1 to 5 carbon atoms, an aryl group having 6 to 12 carbon atoms, a hydroxyl group having 0 to 4 carbon atoms, or an alkoxy group having 0 to 4 carbon atoms.
[0027] After that, a purifying gas (e.g., an inert gas such as Ar) is supplied into the interior of the cavity to discharge unadsorbed modifier or by-products.
[0028] After that, the substrate is exposed to an etching active agent supplied into the interior of the cavity, and the etching active agent reacts with the modifier to etch the thin film. The etching active agent is supplied at 50°C to 700°C.
[0029] Specifically, the etching active agent can be represented by the following Chemical Formula 3: <Chemical Formula 3> In Chemical Formula 3, n is each selected from integers of 0 to 8, R1 to R3 are each a straight-chain alkyl group, a branched-chain alkyl group, or a cycloalkyl group having 1 to 5 carbon atoms, and R4 is selected from hydrogen, a straight-chain alkyl group, a branched-chain alkyl group, or a cycloalkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms.
[0030] Also, the etching active agent can be one of O3, O2, or H2O.
[0031] After that, a purifying gas (e.g., an inert gas such as Ar) is supplied into the interior of the cavity to discharge unreacted etching active agent or by-products.
[0032] - Example 1: Dichloromethyl methyl ether + O3
[0033] Dichloromethyl methyl ether is used as the chlorine modifier, and O3 is used as the etching active agent to etch Nb2O5, Ta2O5, HfO2, TiO2, TiN, TiSiN, MoN, and Mo thin films.
[0034] Based on Figure 1 The etching process of the thin film in the shown supply cycle is as follows, and the following steps are implemented as one cycle.
[0035] 1) The modifier is supplied into the interior of the cavity, and the modifier is adsorbed onto the substrate.
[0036] 2) Ar gas is supplied into the interior of the cavity to discharge unadsorbed modifier or by-products.
[0037] 3) An etching activator is supplied to the interior of the chamber, and the etching activator reacts with the modifier to etch the thin film.
[0038] Figures 2 to 10 It is a graph comparing the thin film thickness of each cycle according to whether an etching activator is used in Example 1 of the present invention. When only dichloromethyl methyl ether is used as the chlorine modifier (w / o etching activator), almost no etching occurs on any thin film.
[0039] On the other hand, when an etching activator (w / etching activator) is used, it is confirmed that the thickness of the thin film linearly decreases on most of the thin films. It is confirmed that through the surface reaction of the two substances, the thin film at the atomic layer level can be uniformly etched.
[0040] This can be explained as follows: The chlorine modifier forms a modified monolayer through a substitution reaction with the metal element on the upper surface, or exists on the surface through physical adsorption, and when an oxygen-containing etching activator is added, the chlorine modifier is removed by forming a volatile by-product represented as M(Cl) a (O) b of the metal chlorooxide.
[0041] Table 1 below shows the etching rate of the thin film based on what was confirmed in Example 1.
[0042] [Table 1]
[0043] - Example 2: 2-chloro-1,1,1-trimethoxyethane + O3
[0044] 2-chloro-1,1,1-trimethoxyethane is used as the chlorine modifier, and O3 is used as the etching activator to etch the Nb2O5 thin film.
[0045] Based on Figure 1 the etching process of the thin film for the shown supply cycle is as follows, and the following steps are carried out as one cycle.
[0046] 1) The modifier is supplied to the interior of the chamber, and the modifier is adsorbed onto the substrate.
[0047] 2) Ar gas is supplied to the interior of the chamber to discharge the unadsorbed modifier or by-products.
[0048] 3) The etching activator is supplied to the interior of the chamber, and the etching activator reacts with the modifier to etch the thin film.
[0049] Figure 11It is a graph comparing the film thickness of each cycle according to whether an etching activator is used in Example 2 of the present invention. When only 2-chloro-1,1,1-trimethoxyethane is used as the chlorine modifier (w / o etching activator), almost no etching occurs on the Nb2O5 film.
[0050] On the other hand, when an etching activator is used (w / etching activator), it was confirmed that the thickness of the film decreased linearly. It was confirmed that through the surface reaction of the two substances, the film at the atomic layer level could be etched uniformly.
[0051] - Example 3: 2-chloro-1,1,1-trimethoxyethane + trimethyl orthoformate
[0052] 2-chloro-1,1,1-trimethoxyethane was used as the chlorine modifier, and trimethyl orthoformate was used as the etching activator to etch the Nb2O5 film.
[0053] Based on Figure 1 The etching process of the film for the shown supply cycle is as follows, and the following steps are implemented as one cycle.
[0054] 1) The modifier is supplied into the interior of the chamber, and the modifier is adsorbed onto the substrate.
[0055] 2) Ar gas is supplied into the interior of the chamber to discharge the unadsorbed modifier or by-products.
[0056] 3) The etching activator is supplied into the interior of the chamber, and the etching activator reacts with the modifier to etch the film.
[0057] Figure 12 It is a graph comparing the film thickness of each cycle according to whether an etching activator is used in Example 3 of the present invention. When only 2-chloro-1,1,1-trimethoxyethane is used as the chlorine modifier (w / o etching activator), almost no etching occurs on the Nb2O5 film.
[0058] On the other hand, it was confirmed that when an etching activator is used (w / etching activator), the thickness of the film decreased linearly. It was confirmed that through the surface reaction of the two substances, the film at the atomic layer level could be etched uniformly.
[0059] The following Table 2 shows the etching rate of the film confirmed based on Examples 2 and 3.
[0060] [Table 2]
[0061] - Example 4: 1-chloroethyl methyl ether + trimethyl orthoacetate
[0062] 1-Chloroethyl methyl ether is used as a chlorine modifier, and trimethyl orthoacetate is used as the etching activator to etch the thin films of TiO2 and Nb2O5.
[0063] Based on Figure 1 The etching process of the thin film based on the shown supply cycle is as follows, and the following steps are implemented as one cycle.
[0064] 1) The modifier is supplied into the interior of the chamber, and the modifier is adsorbed onto the substrate.
[0065] 2) Ar gas is supplied into the interior of the chamber to discharge the unadsorbed modifier or by-products.
[0066] 3) The etching activator is supplied into the interior of the chamber, and the etching activator reacts with the modifier to etch the thin film.
[0067] The following Table 3 shows the etching rate of the thin film confirmed by Example 4.
[0068] [Table 3]
[0069] According to the embodiment of the present invention, the thin film can be removed uniformly.
[0070] In addition, since the etching activator is uniformly adsorbed on the surface of the etching target material of the atomic layer, the etching degree can be precisely controlled compared with the conventional etching method.
[0071] The present invention has been described in detail with reference to the embodiments, but other embodiments may also be included. Accordingly, the technical idea and scope described in the following claims are not limited to the above embodiments.
Claims
1. A method for forming a thin film using a chemical purification material, characterized in that: It includes: A step of supplying a halogen-containing modifier into the interior of a chamber having a substrate disposed therein to adsorb the modifier onto a thin film formed on the substrate; A step of purifying the interior of the chamber; A step of supplying an etching active agent into the interior of the chamber to react the etching active agent with the adsorbed modifier and treat the thin film; and A step of purifying the interior of the chamber.
2. The thin film forming method according to claim 1, characterized in that: The modifier is represented by the following Chemical Formula 1 or Chemical Formula 2: <Chemical Formula 1> <Chemical Formula 2> In Chemical Formula 1 or Chemical Formula 2, X1 and X2 are each hydrogen, a chlorine element, or a chloroalkyl group having 1 to 5 carbon atoms, and R1 to R3 are each selected from hydrogen, a straight-chain alkyl group, a branched-chain alkyl group, or a cycloalkyl group having 1 to 5 carbon atoms, an aryl group having 6 to 12 carbon atoms, a hydroxyl group having 0 to 4 carbon atoms, or an alkoxy group having 0 to 4 carbon atoms.
3. The thin film forming method according to claim 1, characterized in that: The etching active agent is represented by the following Chemical Formula 3: <Chemical Formula 3> In Chemical Formula 3, n is each selected from integers of 0 to 8, and R1 to R3 are each a straight-chain alkyl group, a branched-chain alkyl group, or a cycloalkyl group having 1 to 5 carbon atoms, and R4 is selected from hydrogen, a straight-chain alkyl group, a branched-chain alkyl group, or a cycloalkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms.
4. The thin film forming method according to claim 1, characterized in that: The etching active agent is one of O3, O2, or H2O.
5. The thin film forming method according to claim 1, characterized in that: The thin film has Al, Ti, Hf, Nb, Ta, Mo, or W as a central element.
6. The thin film forming method according to claim 1, characterized in that: The thin film is one of a metal film, a metal oxide, a metal nitride, or a metal sulfide.
7. The thin film forming method according to claim 1, characterized in that: The thin film forming method is carried out at 50°C to 700°C.
8. A method for manufacturing a volatile memory device, characterized in that: It includes the thin film treatment method according to any one of claims 1 to 7.
9. A method for manufacturing a non-volatile memory device, characterized in that: It includes the thin film treatment method according to any one of claims 1 to 7.