Method of forming dielectric film

Abstract

This invention relates to a method for forming a dielectric film. The dielectric film in this embodiment is formed using a substrate processing apparatus, which includes: at least one processing module comprising a chamber for performing a process in a vacuum environment; a transfer module maintaining the vacuum state and disposed adjacent to the processing module to transport and remove the substrate; a standby module storing and idling the substrate in an atmospheric pressure environment; and a loading and locking module located between the transfer module and the standby module to buffer the pressure difference between the transfer module and the standby module. First, after loading the substrate in the chamber, at least one high-dielectric thin film is deposited on the substrate. The substrate with the high-dielectric thin film formed is unloaded to the standby module and normalized for a predetermined time to form a leakage-proof film including a natural oxide film on the high-dielectric thin film; and the at least one high-dielectric thin film is deposited on the natural oxide film.

Description

[Technical Field]

[0001] This invention relates to a semiconductor manufacturing technology, and more specifically, to a method for forming a dielectric film that ensures high dielectric constant and leakage current characteristics. [Previous Technology]

[0002] A representative semiconductor storage device is DRAM. In order to improve the capacity of DRAM, research is ongoing on increasing the surface area of ​​capacitor electrodes, changing the shape of three-dimensional capacitor electrodes, and increasing the dielectric constant of capacitor dielectric film.

[0003] Currently, techniques have been proposed to use high-dielectric films such as HfO2 and ZrO2 as capacitor dielectric films. However, while these high-dielectric films provide a high dielectric constant, they also suffer from high leakage current. To improve the leakage current of high-dielectric films, a technique has been proposed to insert an anti-leakage film within the high-dielectric film. Al2O3 films, as a representative example of such anti-leakage film, are being used.

[0004] However, Al₂O₃ remains in an amorphous state within a temperature range of approximately 300°C during the ALD process, resulting in a very low dielectric constant of 8. Therefore, while using Al₂O₃ as an anti-leakage film can improve the leakage current of the dielectric film, it also reduces the dielectric constant of the dielectric film. [Summary of the Invention]

[0005] The Problem to be Solved

[0006] This embodiment provides a method for forming a dielectric film that prevents leakage current while ensuring a high dielectric constant. (Means of Problem Solving)

[0007] According to an embodiment of the present invention, a method for forming a dielectric film using a substrate processing apparatus includes: at least one processing module including a chamber for performing a process in a vacuum environment; a transfer module maintaining the vacuum state and disposed adjacent to the processing module to transport and remove the substrate from the processing module; a standby module for storing and idling the substrate in an atmospheric pressure environment; and a loading locking module located between the transfer module and the standby module to buffer the pressure difference between the transfer module and the standby module; wherein the dielectric film forming method includes the following steps: after loading the substrate in the chamber, depositing at least one high-dielectric thin film on the substrate; unloading the substrate with the high-dielectric thin film formed thereon to the standby module for normalization for a predetermined time to form a leakage-proof film including a natural oxide film on the high-dielectric thin film; and depositing the at least one high-dielectric thin film on the natural oxide film.

[0008] Furthermore, according to an embodiment of the present invention, a dielectric film forming method is a method for forming a dielectric film on a substrate using a substrate processing apparatus. The substrate processing apparatus includes: a chamber for maintaining a vacuum environment and confining a processing space within it; a substrate support for placing a substrate in a lower region of the chamber; a processing module including a nozzle structure located in an upper region of the chamber and spraying various gases onto the substrate; and a standby module for maintaining an atmospheric pressure environment and room temperature and storing processed or unprocessed substrates. The dielectric film forming method includes: (a) a step of depositing a lower high-dielectric film on the substrate final structure at least once using a first deposition cycle; (b) a step of forming a natural oxide film on the lower high-dielectric film; and (c) a step of depositing an upper high-dielectric film on the natural oxide film at least once using a second deposition cycle. Steps (a) to (c) can be performed at least once. [Effects of the Invention]

[0009] According to this embodiment, a natural oxide film produced through a standardized process can be used as a leakage-proof film inside a high-dielectric film. This ensures leakage current characteristics and a high effective dielectric constant.

Implementation Method

[0011] The advantages, features, and methods of achieving the present invention will become clear from the following detailed description of embodiments, together with the accompanying drawings. However, the technical concept of the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms. These embodiments are provided only to fully disclose the invention and to fully inform those skilled in the art of the invention. The invention is defined only by the scope of the claims. The sizes and relative sizes of layers and regions in the drawings may be exaggerated for clarity of illustration. Throughout the specification, the same element symbols refer to the same components.

[0012] FIG1 is a plan view showing a substrate processing apparatus for depositing dielectric films according to an embodiment of the present invention; FIG2 is a schematic cross-sectional view of the substrate processing apparatus of FIG1.

[0013] Referring to FIG1, the substrate processing apparatus 10 may include: an EFEM 20 (equipment front-end module), a loading and locking chamber 30, a transfer module 40, and a plurality of processing modules 50. The EFEM 20 may be a standby module that maintains an atmospheric pressure (1 standard atmosphere) environment. The EFEM 20 may include a loading port 15, which may include at least one receiving chamber 15a, 15b, 15c referred to as a FOUP (front-opening wafer transfer box). The loading port 15 may be connected to the EFEM 20 and may maintain an atmospheric pressure (approximately 1 standard atmosphere) and a normal temperature (20°C to 25°C).

[0014] The loading locking chamber 30 is located between the standby module EFEM 20 and the transmission module 40, and can buffer the pressure difference between the standby module and the transmission module 40. For example, the loading locking chamber 30 can selectively maintain a vacuum state and an atmospheric pressure state. In the case of the substrate being exchanged between the loading locking chamber 30 and the transmission module 40 which is maintained in a vacuum state, the loading locking chamber 30 can maintain the same vacuum state as the transmission module 40. In addition, in the case of the substrate being exchanged between the loading locking chamber 30 and the standby module (i.e., EFEM 20), the loading locking chamber 30 can maintain atmospheric pressure. Here, the exchange between the two components refers to the movement of the substrate between the two components.

[0015] The standby module (i.e., EFEM 20) may further include a substrate moving component (not shown) that transports substrates between the receiving chambers 15a, 15b, 15c and the loading locking chamber 30. The substrate moving component can move substrates (not shown) stored in the receiving chambers 15a, 15b, 15c to the loading locking chamber 30, and can move the completed substrates from the loading locking chamber 30 to the receiving chambers 15a, 15b, 15c.

[0016] The transfer module 40 may include a transfer robot 45, which transfers substrates provided from the loading and locking chamber 30 to the processing modules 50a, 50b, and 50c, or transfers substrates that have been processed in the processing modules 50a, 50b, and 50c to the loading and locking chamber 30.

[0017] The processing module 50 is configured to connect to the transfer module 40. The transfer module 40 may include a plurality of sides. The loading locking chamber 30 is provided on one side of the transfer module 40, and the processing modules 50a, 50b, and 50c may be provided on the other sides. A gate (not shown) is provided between the processing module 50 and the transfer module 40 for mutual communication.

[0018] FIG2a is a schematic cross-sectional view showing a monolithic processing module according to an embodiment of the present invention.

[0019] As shown in FIG2a, the monolithic processing module 50 may be a monolithic structure including a chamber 100, a single nozzle 110, and a substrate support 120. Furthermore, the processing module 50 may also include an air supply unit 140, a power supply unit 150, a matching network 160, and a controller 180. As an exemplary embodiment, the processing module 50 may be an ALD (Atomic Layer Deposition) apparatus. As another example, the substrate processing apparatus 10 may be a PEALD (Plasma Enhanced Atomic Layer Deposition) apparatus or a PECVD (Plasma Enhanced Chemical Vapor Deposition) apparatus.

[0020] The chamber 100 may include a body 101 and a top cover 105. The body 101 of the chamber 100 defines a space for processing a substrate, i.e., a space for depositing a thin film. The body 101 may have an open upper portion. The top cover 105 may be disposed on the upper outer periphery of the body 101. The top cover 105 is formed into a cover shape having a window (not shown) into which the nozzle 110 can be inserted. Depending on the situation, the substrate processing apparatus 10 may also include an insulating ring r, which intervenes between the nozzle 110 and the top cover 105. The insulating ring r electrically insulates the chamber 100, and more specifically the top cover 105 and the nozzle 110.

[0021] A gate G may be configured on the side of the main body 101. The substrate to be processed can be loaded and unloaded through the gate G.

[0022] The chamber 100 may further include an exhaust port 102, which is connected to the lower end of the main body 101. Additionally, the substrate processing apparatus 10 may also include a pump 103, which is connected to the exhaust port 102. Through the suction action of the pump 103, the interior of the main body 101 can be vacuumed, and process residues can be discharged through the exhaust port 102.

[0023] The nozzle 110 is inserted into the viewing window of the top cover 105 and can be configured to face the substrate support 120. The nozzle 110 receives source gas and reaction gas from the gas supply unit 140 and can spray it onto the substrate W placed on the substrate support 120. As an exemplary embodiment, the nozzle 110 is electrically connected to the power supply unit 150 and can perform the operation of a first electrode for generating plasma.

[0024] The substrate support portion 120 may include a substrate placement portion 122 (base) and a support shaft 124. The substrate placement portion 122 may generally have a flat plate shape for placing at least one substrate W on it. The support shaft 124 may be perpendicularly coupled to the rear of the substrate placement portion 122. The support shaft 124 may receive a driving force and may raise, lower, and / or rotate the substrate placement portion 122. As an exemplary embodiment, the substrate placement portion 122 may have a built-in heater 125. The heater 125 may regulate the temperature of the substrate W to be processed. In addition, the substrate support portion 120 may perform an operation as a second electrode for generating the plasma in order to receive a ground voltage.

[0025] Here, the distance between the nozzle 110 and the substrate support 120 (e.g., gas jet distance) is one of the deposition conditions and may vary depending on the process.

[0026] For example, the gas supply unit 140 may include at least one source gas supply unit 140a and at least one reaction gas supply unit 140b. For example, the source gas supply unit 140a may include a metal precursor for depositing a high-dielectric film. For example, the metal precursor may include any one of Zr, Hf, Al, La and Y. As an example, the source gas supply unit 140a may include a Zr source, which includes ZrCl 4, Zr[N(CH 3)C 2H 5] 4, Zr(O-tBu) 4, Zr[N(CH 3) 2] 4, Zr[N(C 2H 5)(CH 3)] 4, Zr[N(C 2H 5) 2] 4, Zr(tmhd) 4, Zr(OiC 3H 7) 3(tmtd), Zr(OtBu) 4 and zirconium-containing compounds. As another example, the source gas supply unit 140a may include an Hf source, such as C16H36HfO4, TDEAHf, or TEMAHf.

[0027] The reaction gas supply unit 140b may include a reaction gas for reacting with the metal precursor. For example, the reaction gas composition may include an O2 source, an H2O source, an N2O source, or an O3 source. Additionally, although not shown, the gas supply unit 140 may also include an inhibitor gas supply unit and a purge gas supply unit.

[0028] The gas supply unit 140 can be connected to the nozzle 110 via a gas supply line L. At least one valve V1 and V2 can be installed in the gas supply line L. The valves V1 and V2 can adjust the amount of gas supplied in the gas supply unit 140.

[0029] The power supply unit 150 can apply a power supply voltage for generating plasma to the nozzle 110. The matching network 160 matches the impedance of the power supply unit 150 with the impedance of the chamber 100, thereby reducing power loss.

[0030] The controller 180 is configured to control the overall operation of the substrate processing apparatus 10. For example, the controller 180 can control the driving of each component (110-160, V1, V2) of the substrate processing apparatus 10.

[0031] In addition, although not shown, the controller 180 may include a central processing unit, memory, input / output ports, etc.

[0032] The substrate stored in the loading port 15 can be transferred to the loading locking chamber 30 through the substrate transfer module 20. The substrate waiting in the loading locking chamber 30 can be transferred to the processing module 50 for depositing dielectric film through the transfer module 40.

[0033] FIG2b is a schematic cross-sectional view of a processing module with a spatial division method according to an embodiment of the present invention; FIG2c is a plan view of the nozzle structure of FIG2b. For reference, FIG2b may be a cross-sectional view taken along line b-b' of FIG2c. In addition, in this embodiment, a structure different from the monolithic processing module 50 of FIG2a is described, and related repetitive descriptions of actually identical structures are excluded.

[0034] Referring to Figures 2a and 2c, the spatially segmented processing module 51 may include: a chamber 100a, a nozzle structure 111 including a plurality of gas injection sections 111a to 111g, a gas supply section 141, and a substrate support section 121 supporting a plurality of substrates W.

[0035] The nozzle structure 111 may include: at least one inhibitor gas injection section 111a, at least one purge gas injection section 111b, 111d, 111f, at least one source gas injection section 111c, at least one reaction gas injection section 111e, and an air curtain gas injection section 111g.

[0036] As an exemplary embodiment, considering the process sequence, the nozzle structure 111 may include an inhibitor gas injection section 111a, a first purge gas injection section 111b, a source gas injection section 111c, a second purge gas injection section 111d, a reaction gas injection section 111e, and a third purge gas injection section 111f arranged sequentially. The order of the gas injection sections (111a to 111f) can, of course, change depending on the process sequence.

[0037] The inhibitor gas jet 111a, the first purge gas jet 111b, the source gas jet 111c, the second purge gas jet 111d, the reaction gas jet 111e, and the third purge gas jet 111f can be arranged radially with reference to the center of the nozzle structure 111. Additionally, an air curtain gas jet 111g can be disposed at the center of the nozzle structure 111 to prevent unwanted mixing of the gases.

[0038] The gas supply unit 141 may include: inhibitor gas supply unit 141a, purge gas supply unit 141b, source gas supply unit 141c, reaction gas supply unit 141e, and curtain gas supply unit 141g.

[0039] The inhibitor gas supply unit 141a can be connected to the inhibitor gas injection unit 111a via a gas supply line L. The purge gas supply unit 141b can be connected to the first to third purge gas injection units 111b, 111d, and 111f via at least one gas supply line L. The source gas supply unit 141c is connected to the source gas injection unit 111c via a gas supply line L, and the reaction gas supply unit 141e can be connected to the reaction gas injection unit 111e via a gas supply line L. Valves V can be installed inside the gas supply lines L to selectively adjust the gas injection and flow rate.

[0040] The substrate support portion 121 may include a plurality of substrate placement portions 122a. The plurality of substrate placement portions 122a are located at positions corresponding to the inhibitor gas injection portion 111a, the first purge gas injection portion 111b, the source gas injection portion 111c, the second purge gas injection portion 111d, the reaction gas injection portion 111e, and the third purge gas injection portion 111f, respectively.

[0041] In order for the substrates W mounted on the plurality of substrate placement portions 122a to be processed sequentially, the substrate support portion 121 can be rotated and raised / lowered.

[0042] As an exemplary embodiment, the nozzle structure 111 of the spatially segmented processing module 51 includes an inhibitor gas jetting section 111a, a first purge gas jetting section 111b, a source gas jetting section 111c, a second purge gas jetting section 111d, a reaction gas jetting section 111e, and a third purge gas jetting section 111f, each continuously jetting gas. The substrate support section 121 rotates by a predetermined angle, thereby depositing a thin film, such as a dielectric film, on the substrate W. Here, the predetermined angle may refer to the angle formed with adjacent gas jetting sections.

[0043] FIG3 is a cross-sectional view illustrating a dielectric film formation method according to an embodiment of the present invention; FIG4 is a flowchart illustrating a dielectric film formation method according to an embodiment of the present invention; FIG5 is a timing diagram illustrating a dielectric film formation method according to an embodiment of the present invention.

[0044] Referring to Figures 1 to 5, a substrate (not shown) is mounted on the processing module 50. The processing module 50 (i.e., inside the chamber 100) can create a process environment for depositing a dielectric film. For example, the chamber 100 can maintain a temperature of, for example, 250 to 400°C and a vacuum environment, and through the drive of the power supply unit 150, the chamber 100 can be in a state where plasma has been generated. In the chamber 100 where such a process environment is created, a lower high-dielectric film 210 can be deposited at least once (S10). As an exemplary embodiment, the lower high-dielectric film 210 may include an atomic layer, which can be formed in a single deposition cycle. At this time, the deposition cycle may include, for example, an inhibitor gas injection step S11, a first purge gas injection step S12, a source gas injection step S13, a second purge gas injection step S14, a reactive gas injection step S15, and a third purge gas injection step S16. For example, the first to third purge gases may contain the same purge gas, but are not limited to this. Firstly, the inhibitor gas injection step S11 may be performed to deposit the lower high-dielectric film 210 at a uniform thickness when depositing it on an uneven surface. For example, the inhibitor gas may contain a gas that reduces the reactivity between the first gas and the deposition surface. Accordingly, the adsorption of the first gas component relative to the portion forming a thicker lower high-dielectric film 210 can be delayed. In this case, depending on the deposition surface state of the lower high-dielectric film 210 to be deposited, the inhibitor gas injection step S11 may be omitted.

[0045] The first purge gas injection step S12 is to remove residual inhibitor components that have not been adsorbed onto the deposition surface by using purge gas.

[0046] Then, the source gas injection step S13 involves supplying the source gas to the nozzle 110 with the valve V1 in FIG2 open. The nozzle 110 is capable of injecting the source gas onto the substrate according to a set flow rate. The source gas components can be physicochemically adsorbed onto the surface to be deposited. After the source gas injection step S13, the valve V1 is closed.

[0047] The second purge gas injection step S14 is to inject purge gas onto the final structure of the substrate that has adsorbed the source gas, and remove the source gas components that have not been adsorbed by the purge gas.

[0048] Then, in the reactive gas injection step S15, the reactive gas is supplied to the nozzle 110 with the valve V2 open as shown in FIG2. The nozzle 110 injects the reactive gas onto the substrate according to a set flow rate. The reactive gas reacts with the source gas components adsorbed on the final structure of the substrate to form a lower high-dielectric film 210. After completing the reactive gas injection step S15, the valve V2 is closed.

[0049] Then, the third purge gas injection step S16 can remove unreacted reaction gas components.

[0050] Repeating the deposition cycle once or more can form the lower high dielectric film 210.

[0051] Then, a standardization process (S20) can be performed on the substrate to which the lower high-dielectric film 210 has been deposited. In this embodiment, the standardization process may include a process of cooling the substrate for a predetermined time in a device that maintains room temperature and atmospheric pressure. Through the standardization process, the stress of the thin film (lower high-dielectric film 210) deposited in the previous process is relieved, the grain size of the lower high-dielectric film 210 is refined and standardized, and the mechanical properties of the lower high-dielectric film 210 can be improved.

[0052] As an exemplary embodiment, the standardization process of this embodiment can be a process of idling for a predetermined time in the loading port 15 of the standby module (i.e., EFEM 20) while maintaining atmospheric pressure and room temperature. During this process, a natural oxide film can be generated on the surface of the lower high-dielectric film 210. In this embodiment, the natural oxide film is used as the leakage-proof film 220 of the dielectric film. At this time, the thickness of the leakage-proof film 220 can be taken into account to adjust the standardization process time. For example, the standardization process of this embodiment can be performed for 3 to 7 minutes.

[0053] Then, the substrate with the anti-leakage film 220 formed is reloaded into the processing module 50 via the substrate transfer module 20, the loading locking chamber 30, and the transfer module 40. Then, an upper high-dielectric film 230 is deposited at least once on the anti-leakage film 220 (S30). For example, the upper high-dielectric film 230 may contain the same material as the lower high-dielectric film 210. The upper high-dielectric film 230 includes at least one atomic layer, which may be obtained by a single deposition cycle. For example, the deposition cycle for depositing the upper high-dielectric film 230 may include: an inhibitor gas injection step S31, a purge gas injection step S32, a source gas injection step S33, a purge gas injection step S34, a reactive gas injection step S35, and a purge gas injection step S36. When the upper high-dielectric film 230 and the lower high-dielectric film 210 are made of the same material, the deposition period of the upper high-dielectric film 230 and the deposition period of the lower high-dielectric film 210 can be the same. Therefore, repeated explanations are omitted.

[0054] FIG6 is a flowchart illustrating a dielectric film formation method according to an embodiment of the present invention; FIG7 is a timing diagram illustrating a dielectric film formation method according to an embodiment of the present invention.

[0055] Referring to Figures 6 and 7, the dielectric film formation method may include: a step of depositing a lower high dielectric film at least once (S50), a step of forming a leakage prevention film 220 by a standardized process (S60), and a step of depositing an upper high dielectric film different from the lower high dielectric film at least once (S70).

[0056] First, the lower high-dielectric film deposition step S50 can be repeatedly performed several times using the first deposition cycle for forming the lower high-dielectric atomic layer. For example, the first deposition cycle may include: inhibitor gas injection step S51, purge gas injection step S52, first source gas injection step S53, the purge gas injection step S54, the first reactive gas injection step S55, and the purge gas injection step S56. This first deposition cycle can actually be the same as the deposition cycle in FIG4.

[0057] As described above, the step (S60) of forming the anti-leakage film through a standardized process involves exposing the substrate to ambient temperature and atmospheric pressure for a predetermined time, thereby forming an anti-leakage film including a natural oxide film. The standardized process S60 can also be performed after the lower high-dielectric film deposition step S50. As another example, the standardized process S60 can also be performed between the first deposition cycles (S51-S56) of the lower high-dielectric film. Accordingly, an anti-leakage film (i.e., a natural oxide film) can be inserted between the atomic layers of the lower high-dielectric film.

[0058] The step of depositing the upper high-dielectric atomic layer, which is different from the lower high-dielectric film (S70), can be repeated several times in the second deposition cycle. For example, the second deposition cycle may include: inhibitor gas injection step S71, purge gas injection step S72, second source gas injection step S73, which is different from the first source gas, purge gas injection step S74, second reaction gas injection step S75, and purge gas injection step S76. The second deposition cycle differs from the first deposition cycle only in the types of source gas and / or reaction gas; the actual process mechanism can be the same. For example, the second reaction gas in the second deposition cycle can be the same gas as the first reaction gas in the first deposition cycle. In addition, the standardization process S60 can also be implemented between the second deposition cycles (S71-S75). Accordingly, a leakage-proof film including the natural oxide film can be formed between the atomic layers constituting the upper high-dielectric film.

[0059] In addition, in the above embodiment, the purge gas and the reaction gas are provided only in the above steps, but they can also be supplied continuously as needed.

[0060] Figures 8a to 8d are cross-sectional views illustrating the dielectric film according to an embodiment of the present invention.

[0061] Referring to FIG8a, the dielectric film 200a of this embodiment may include: a lower high-dielectric film 210-1, a leakage-proof film 220, and an upper high-dielectric film 230-1. The lower high-dielectric film 210-1 may include a plurality of lower high-dielectric films. For example, the lower high-dielectric film 210-1 may include a first lower high-dielectric film 210a, a second lower high-dielectric film 210b, and a third lower high-dielectric film 210c stacked sequentially. The first to third lower high-dielectric films 210a to 210c may each be an atomic layer obtained through at least one deposition cycle. The first to third lower high-dielectric films 210a to 210c may be formed in situ.

[0062] The leakage protection film 220 may be located between the lower high dielectric film 210-1 and the upper high dielectric film 230-1, for example, it may be located at the center of the dielectric film 200a.

[0063] The upper high-dielectric film 230-1 may contain the same or different material as the lower high-dielectric film 210-1. In this embodiment, the upper high-dielectric film 230-1 may include a plurality of upper high-dielectric films and at least one secondary leakage protection film 220a, wherein the at least one secondary leakage protection film 220a is interposed between the plurality of upper high-dielectric films. For example, the upper high-dielectric film 230-1 may include a first upper high-dielectric film 230a, a second upper high-dielectric film 230b, a secondary leakage protection film 220a, and a third upper high-dielectric film 230c stacked sequentially. However, it is not limited thereto. For example, the first upper high-dielectric film 230a, the second upper high-dielectric film 230b, and the third upper high-dielectric film 230c may each be an atomic layer obtained through a single deposition cycle. In addition, the first upper high-dielectric thin film 230a and the second upper high-dielectric thin film 230b, which are deposited continuously, can be formed in situ.

[0064] In this embodiment, the anti-leakage film 220 and the secondary anti-leakage film 220a can each be a natural oxide film obtained through the above-described standardized process. The anti-leakage film 220 and the secondary anti-leakage film 220a can have the same thickness or different thicknesses. In this case, the thickness of the anti-leakage films 220 and 220a can be adjusted based on the standardized process time (i.e., standby time).

[0065] Additionally, Figure 8a shows an example of forming a secondary leakage protection film 220a within the upper high dielectric film 230-1, but by performing a standardized process between deposition cycles (i.e., between the upper high dielectric film 230a and 230b), a plurality of secondary leakage protection films 220a can be formed.

[0066] According to this embodiment, leakage prevention films 220 and 220a can be formed inside the center of the dielectric film 200a and inside the upper high-dielectric film 230-1 corresponding to the upper region of the dielectric film 200a. Accordingly, leakage current occurring inside the dielectric film 200a and in the upper region (e.g., the plate electrode side) can be reduced.

[0067] Referring to FIG8b, the dielectric film 200b of this embodiment may include: a lower high dielectric film 210-2, a leakage protection film 220, and an upper high dielectric film 230-2, wherein the lower high dielectric film 210-2 includes a secondary leakage protection film 220a.

[0068] The lower high-dielectric film 210-2 may include a plurality of lower high-dielectric films and at least one secondary anti-leakage film 220a, wherein the at least one secondary anti-leakage film 220a is interposed between the plurality of lower high-dielectric films. For example, the lower high-dielectric film 210-2 may include a first lower high-dielectric film 210a, a secondary anti-leakage film 220a, a second lower high-dielectric film 210b, and a third lower high-dielectric film 210c stacked sequentially, but is not limited thereto.

[0069] The anti-leakage film 220 may be located between the lower high-dielectric film 210-2 and the upper high-dielectric film 230-2. In this embodiment, the anti-leakage film 220 and the secondary anti-leakage film 220a may be formed by a standardized process.

[0070] As an exemplary embodiment, FIG8b shows an example of forming a secondary leakage protection film 220a within the lower high dielectric film 210-2, but of course, a plurality of secondary leakage protection films 220a may also be formed by performing a standardized process between deposition cycles (i.e., between the lower high dielectric films).

[0071] The upper high-dielectric film 230-2 may contain the same or different material as the lower high-dielectric film 210-2. For example, the upper high-dielectric film 230-2 may include a first to a third upper high-dielectric film 230a, 230b, and 230c stacked sequentially. The first to third upper high-dielectric films 230a, 230b, and 230c may each be atomic layers obtained through at least one deposition cycle and may be formed in situ.

[0072] According to this embodiment, leakage prevention films 220 and 220a can be inserted in the center of the dielectric film 200b, for example, between the lower high-dielectric film 210-2 and the upper high-dielectric film 230-2, and inside the lower high-dielectric film 210-2 corresponding to the lower region of the dielectric film 200b. This reduces leakage current occurring inside the dielectric film 200b, especially in the lower region (e.g., the storage electrode).

[0073] Referring to FIG8c, the dielectric film 200c of this embodiment may include: a lower high-dielectric film 210-3, a leakage-proof film 220, and an upper high-dielectric film 230-3. The lower high-dielectric film 210-3 includes at least one secondary leakage-proof film 220a, and the upper high-dielectric film 230-3 includes at least one secondary leakage-proof film 220a. The leakage-proof film 220 and the secondary leakage-proof film 220a may be formed by a standardized process.

[0074] For reference, Figure 8c shows an example in which the lower high-dielectric film 210-3 and the upper high-dielectric film 230-3 each include a secondary leakage protection film 220a, but is not limited thereto. Instead, the standardized process is performed between the deposition cycles for forming the various films (210a-210c, 230a-230c), thereby forming a plurality of secondary leakage protection films 220a at locations where leakage current is likely to occur.

[0075] As described above, between the lower high dielectric film 210-2 and the upper high dielectric film 230-2, which are located at the center of the dielectric film 200c, leakage protection films 220 and 220a are respectively inserted in the lower region and the upper region. Therefore, leakage current can be reduced not only in the center of the dielectric film 200c, but also in the upper and lower regions.

[0076] As another example, referring to FIG8d, the dielectric film 200d of this embodiment may include a lower high-dielectric film 210-4 and an upper high-dielectric film 230-4. At least one of the lower high-dielectric film 210-4 and the upper high-dielectric film 230-4 may include a secondary leakage protection film 220a. As an exemplary embodiment, the lower high-dielectric film 210-4 and the upper high-dielectric film 230-4 may each include a secondary leakage protection film 220a.

[0077] As described above, by forming a secondary anti-leakage film 220a on the lower and upper regions of the dielectric film 200d, leakage current in the lower and upper regions of the dielectric film 200d can be prevented.

[0078] As a result, considering the leakage location of the dielectric film, the anti-leakage film can be inserted in areas with a relatively high leakage current occurrence rate. Alternatively, a relatively thicker anti-leakage film can be formed in areas where the leakage current occurrence rate is relatively high.

[0079] FIG9 is a cross-sectional view of a semiconductor device including a capacitor according to an embodiment of the present invention.

[0080] Referring to FIG9, an interlayer insulating film 310 is formed on the upper part of the semiconductor substrate 300. Although not shown in the figure, circuit elements can be assembled between the semiconductor substrate 300 and the interlayer insulating film 310.

[0081] The interlayer insulating film 310 may have a storage node contact portion 320 that is connected to the circuit element.

[0082] A storage electrode 330 may be formed on the upper part of the storage node contact portion 320. For example, the storage electrode 330 may be formed as a cylinder structure. Accordingly, the final structure of the semiconductor substrate 300 may have an uneven surface due to the structure of the storage electrode 330.

[0083] A dielectric film 340 according to this embodiment may be formed on the upper part of the interlayer insulating film 310 and the surface of the storage electrode 330. The dielectric film 340 of this embodiment may include at least one of the dielectric films shown in FIG3, FIG8a to FIG8d.

[0084] A plate electrode 350 may be formed on the upper part of the dielectric film 340.

[0085] According to this embodiment, at least one anti-leakage film 220 comprising a natural oxide film is inserted inside the dielectric film 340, thereby blocking the flow of leakage current not only inside the dielectric film 340, but also at the interface between the dielectric film 340 and the storage electrode 330 or at the interface between the dielectric film 340 and the plate electrode 350.

[0086] Figure 10 is a graph showing the leakage current of the dielectric film according to the applied voltage according to an embodiment of the present invention; Figure 11 is a graph showing the dielectric constant of the dielectric film according to an embodiment of the present invention.

[0087] Referring to FIG10, (a) is a leakage current curve of the natural oxide film of this embodiment as a leakage protection film including a dielectric film; (b) is a leakage current curve of Al2O3 of the comparative example as a leakage protection film including a dielectric film.

[0088] Comparing the results of curves (a) and (b), it was observed that the leakage current of curve (a) was lower than that of curve (b) in the low voltage band (-1V to 1V), and that both (a) and (b) showed similar levels of leakage current in the high voltage band (±1V to ±2V).

[0089] Referring to FIG11, (c) shows the effective dielectric constant of the natural oxide film of this embodiment as a leakage-proof film containing a dielectric film; (d) shows the effective dielectric constant of Al2O3 of the comparative example as a leakage-proof film containing a dielectric film.

[0090] Assuming the dielectric constant of the high-dielectric film, which constitutes the majority of the dielectric film, is approximately 35, in case (c), due to the dielectric constant of the natural oxide film, the effective dielectric constant of the dielectric film is approximately 25 to 27. On the other hand, in case (d) where Al₂O₃ is used as an anti-leakage film, the Al₂O₃ film is amorphous when moved between chambers used for depositing the Al₂O₃ film, thus the surface of the Al₂O₃ film can be converted into AlO. It is well known that amorphous AlO has a low dielectric constant of approximately 8, thus drastically reducing the overall effective dielectric constant of the dielectric film to approximately 10.

[0091] Based on the results of leakage current and dielectric constant in Figures 10 and 11, when the leakage protection film containing the natural oxide film in this embodiment is applied to a high dielectric film, it exhibits a similar leakage current distribution to the dielectric film for which Al2O3 leakage protection film is applied, while ensuring a higher effective dielectric constant than when Al2O3 leakage protection film is applied.

[0092] As detailed above, according to this embodiment, the natural oxide film produced through a standardized process can be used as a leakage-proof film inside the high-dielectric film. Accordingly, leakage current characteristics and a higher effective dielectric constant can be ensured.

[0093] In addition, the embodiments disclosed an example of implementing a standardized process in a standby module, but it is not limited thereto. The standardized process can also be implemented in modules that maintain an atmospheric pressure environment other than standby modules (e.g., loading lock modules).

[0094] The present invention has been described in detail above through preferred embodiments, but the present invention is not limited to the embodiments described, and various changes can be made by those skilled in the art within the scope of the technical concept of the present invention. [Simplified Explanation of the Diagram]

[0010] FIG1 is a plan view showing a substrate processing apparatus for depositing a dielectric film according to an embodiment of the present invention; FIG2a is a schematic cross-sectional view showing a monolithic processing module according to an embodiment of the present invention; FIG2b is a schematic cross-sectional view of a processing module with spatial division according to an embodiment of the present invention; FIG2c is a plan view of the nozzle structure of FIG2b; FIG3 is a cross-sectional view illustrating a dielectric film formation method according to an embodiment of the present invention; FIG4 is a flowchart illustrating a dielectric film formation method according to an embodiment of the present invention; FIG5 is a timing diagram illustrating a dielectric film formation method according to an embodiment of the present invention; FIG6 is a flowchart illustrating a dielectric film formation method according to an embodiment of the present invention; FIG7 is a timing diagram illustrating a dielectric film formation method according to an embodiment of the present invention; FIG8a to FIG8d are cross-sectional views illustrating dielectric films according to embodiments of the present invention; FIG9 is a cross-sectional view of a semiconductor device including a capacitor according to an embodiment of the present invention; Figure 10 is a graph showing the leakage current of the dielectric film according to an applied voltage according to an embodiment of the present invention; and Figure 11 is a graph showing the dielectric constant of the dielectric film according to an embodiment of the present invention.

Claims

1. A method for forming a dielectric film, comprising a substrate processing apparatus, the substrate processing apparatus including: At least one processing module includes: a chamber for performing a process in a vacuum environment; a transfer module for maintaining the vacuum state and being configured adjacent to the processing module to transport and remove a substrate from the processing module; a standby module for storing and idling the substrate in an atmospheric pressure environment; and a loading locking module located between the transfer module and the standby module to buffer the pressure difference between the transfer module and the standby module, wherein the dielectric film formation method includes the following steps: after loading the substrate in the chamber, depositing at least one high-dielectric thin film on the substrate; unloading the substrate with the high-dielectric thin film formed thereon to the standby module and normalizing it for a predetermined time in the atmospheric pressure environment to form a leakage-proof film including a natural oxide film on the high-dielectric thin film; and depositing the at least one high-dielectric thin film on the natural oxide film, the natural oxide film being formed by the atmospheric pressure environment and used to prevent leakage current from the high-dielectric thin film.

2. The method for forming a dielectric film according to claim 1, wherein, The standby module maintains a pressure of 1 standard atmosphere and a normal temperature of 20°C to 25°C.

3. The method for forming a dielectric film according to claim 1, wherein, The standby module includes at least one loading port, and wherein, during the formation of the anti-leakage film, the substrate is in standby mode within the loading port.

4. The method for forming a dielectric film according to claim 1, wherein, The high-dielectric thin film deposition step includes the following steps: spraying a first purge gas onto the final structure of the substrate; spraying a source gas onto the substrate on which the first purge gas has been sprayed; spraying a second purge gas to remove residual components of the source gas that have not been adsorbed; and spraying a reaction gas to react with the adsorbed source gas. And a third purge gas is injected to remove any residual components of the reactant gas that have not been adsorbed.

5. The method for forming a dielectric film according to claim 4, wherein, The high-dielectric thin film deposition step includes, before the step of spraying the first purge gas onto the final structure of the substrate, a step of spraying an inhibitor gas onto the upper part of the substrate.

6. A method for forming a dielectric film, comprising forming a dielectric film on a substrate using a substrate processing apparatus, the substrate processing apparatus comprising: A chamber that maintains a vacuum environment and confines a processing space within it; A substrate support is located in the lower region of the chamber and the substrate is placed thereon; a processing module includes a nozzle structure located in the upper region of the chamber and spraying various gases onto the upper part of the substrate. The system includes a standby module that maintains an atmospheric pressure environment and room temperature, and stores the processed or unprocessed substrate. The dielectric film formation method includes: (a) a step of repeatedly performing a first deposition cycle at least once on the final structure of the substrate to deposit a lower high-dielectric film; (b) a step of forming a natural oxide film on the upper part of the lower high-dielectric film; and (c) a step of repeatedly performing a second deposition cycle at least once on the upper part of the natural oxide film to deposit an upper high-dielectric film. The steps (a) to (c) are performed at least once, the natural oxide film is formed by the atmospheric pressure environment, and is used to prevent leakage current from the high-dielectric film.

7. The method for forming a dielectric film according to claim 6, wherein, At least one of the first deposition cycle and the second deposition cycle includes the following steps: spraying a first purge gas onto the substrate; spraying a source gas onto the substrate on which the first purge gas has been sprayed; spraying a second purge gas to remove residual components of the source gas that have not been adsorbed; and spraying a reaction gas to react with the adsorbed source gas. And a third purge gas is injected to remove any residual components of the reactant gas that have not been adsorbed.

8. The method for forming a dielectric film according to claim 7, wherein, Step (a), depositing the lower high-dielectric film, includes repeatedly performing the first deposition cycle several times, and wherein, between the first deposition cycles, there is at least one step of forming the natural oxide film.

9. The method for forming a dielectric film according to any one of claims 6 to 8, wherein, The natural oxide film formation steps include: a standardized step of moving the substrate to the standby module for a predetermined standby time.

10. The method for forming a dielectric film according to claim 7 or 8, wherein, Step (c) of depositing the upper high-dielectric film includes the step of repeatedly performing the second deposition cycle several times, wherein, between the second deposition cycles, there is also a step of forming the natural oxide film at least once, and wherein, there is a standardization step of moving the substrate to the standby module and standing for a set time.

11. The method for forming a dielectric film according to claim 6, wherein, The lower high-dielectric film and the upper high-dielectric film are made of different materials.

12. The method for forming a dielectric film according to claim 6, wherein, The lower high-dielectric film and the upper high-dielectric film have the same or different thicknesses.

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