A thin film production method that uses high-density radicals to nitride the interface

Abstract

According to one embodiment of the present invention, a method for forming an oxide film using a deposition apparatus includes the steps of: (a) depositing a first thin film made of a nitride film on a substrate; (b) forming an oxynitride film in the first thin film by injecting OH radicals into the first thin film to oxidize the first thin film; and (c) forming an insulating film on the first thin film. Either of steps (a) and (b) is selectively repeated to adjust the thickness of the first thin film or the concentration inside the first thin film.

Description

[Technical Field]

[0001] The present invention relates to a method for producing a thin film, and more particularly to a method for producing a thin film by nitriding an interface using high-density radicals. [Background technology]

[0002] With the development of technology, semiconductors, which are the foundation of core technologies of the Fourth Industrial Revolution such as artificial intelligence, big data, 5G, and autonomous vehicles, are requiring multi-layer structures and complex circuit patterns to improve the speed of non-memory (System LSI) devices and increase the capacity of memory (DRAM, 3D_VNAND).

[0003] Accordingly, semiconductor patterning technology with a line width of 5nm or less is currently being secured through the introduction of technologies such as EUV (Extreme Ultraviolet), but there are still issues that must be resolved, such as unevenness in thin film thickness, poor deposition of high aspect ratio contact holes, and poor step coverage, which are emerging as limitations of existing thin film deposition technology.

[0004] In order to solve the above-mentioned problems, conventional thin film formation technology involves oxidizing the substrate or depositing an oxide film on the substrate, and then treating it with NO or NO to allow N to penetrate to the interface, thereby reducing interface defects. This technology ultimately results in improved interface characteristics and reliability.

[0005] However, such conventional techniques also have problems such as environmental issues due to toxic gases, difficulty in controlling the N concentration in the nitride film, and deterioration of electrical characteristics due to interface roughness caused by high temperature processing.

[0006] FIG. 1 is an exemplary diagram showing a conventional interface nitriding process.

[0007] Conventional interface nitridation technology involves oxidizing the substrate (100) or depositing an oxide film on the substrate (100) and then applying a heat treatment using a gas containing N. Specifically, in the conventional technology, as shown in Figures 1(a) and 1(b), an oxide film is formed by oxidation or deposition on a substrate (100), and annealing is performed using a gas containing N (e.g., nitrogen dioxide (NO), nitric oxide (NO), etc.).

[0008] At this time, if annealing is performed excessively to increase the N concentration, the N concentration increases not only at the interface between the substrate (100) and SiO2 but also in the SiO2 itself, which can degrade the characteristics of the semiconductor device.

[0009] On the other hand, if only an oxide film is formed as shown in Figure 1(a), interface defects occur due to incomplete bonds such as dangling bonds at the SiO2 interface with the substrate (100), resulting in a high interface defect density, but if annealing is performed using a gas containing N as shown in Figure 1(b), the incomplete interface defects such as dangling bonds at the interface with the substrate (100) are improved. At this time, O or H can also be used in addition to N depending on the process or material.

[0010] In addition, conventional technology requires considerable energy to break the atomic bonds of SiO2 to form SiON, so high-temperature heat treatment or plasma treatment at temperatures above 900°C is used in conventional post-treatment processes to break the atomic bonds.

[0011] However, the plasma method has the disadvantage of using too much energy, which can adversely affect the durability of semiconductor products or the durability of the deposition equipment itself. Conventional heat treatment methods also have similar disadvantages because they operate at too high a temperature. Generally, because the plasma method uses more energy than the heat treatment method, the plasma method is used when the desired thin film deposition cannot be achieved through the heat treatment method.

[0012] In addition, conventional technology uses a method to break the atomic bonds of SiO2, so when the molecules converted into SiON by reacting with N reach a certain concentration, the reaction with N does not occur and higher energy injection is required. At this time, the N concentration increases in the SiO2 itself, not at the interface between the substrate and SiO2, and there is a limit to the adjustment of the N concentration and SiON thickness, which makes it difficult to improve device characteristics. Summary of the Invention [Problem to be solved by the invention]

[0013] The present invention is intended to solve the problems of the prior art described above, and aims to improve the incomplete bonding at the interface between the substrate and the SiN thin film, which is oxidized by high-density radicals, thereby improving interface defects and thin film properties.

[0014] In addition, SiN is generally difficult to oxidize because it is bonded with high energy, but by controlling the density of radicals by adjusting the gas flow rate and the exposure time and amount of high-density radicals, SiN can be oxidized, with the additional objective of adjusting the N concentration and SiON thickness.

[0015] However, the technical objectives to be achieved by this embodiment are not limited to the above-mentioned technical objectives, and other technical objectives may exist. [Means for solving the problem]

[0016] As a technical means for achieving the above technical object, a method for forming an oxide film using a deposition apparatus includes the steps of: (a) depositing a first thin film made of a nitride film on a substrate; (b) forming an oxynitride film in the first thin film by injecting OH radicals into the first thin film to oxidize the first thin film; and (c) forming an insulating film on the first thin film, and by selectively repeating steps (a) and (b), either the thickness of the first thin film or the concentration inside the first thin film can be adjusted.

[0017] Also, step (a) can be performed by depositing the first thin film based on either CVD or ALD techniques.

[0018] The first thin film may be made of SiN, and the oxynitride film may be made of SiON.

[0019] Also, if the first thin film is made of SiN, SiN may react with OH radicals in step (b) to form SiON.

[0020] In addition, the concentration of the SiON component in the lower part of the nitride oxide film may be lower than the concentration of the SiON component in the upper part of the nitride oxide film.

[0021] In addition, the process of injecting OH radicals in step (b) can be carried out at a process temperature between 480 and 730°C.

[0022] Also, steps (a) to (c) may be included in the process of forming a gate oxide film in the process of forming a semiconductor device. [Effects of the Invention]

[0023] An embodiment of the present invention aims to improve the incomplete bonding at the interface between the substrate and the SiN thin film oxidized by high-density radicals, thereby improving the interfacial defects and thin film properties.

[0024] In addition, SiN is generally difficult to oxidize because it is bonded with high energy, but by controlling the density of radicals by adjusting the gas flow rate and the exposure time and amount of high-density radicals, SiN can be oxidized, with the additional objective of adjusting the N concentration and SiON thickness.

[0025] Based on this, after SiN is deposited, OH radicals can be injected and a subsequent heat treatment can be performed, or SiON can be formed at the interface using the ALD method. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a diagram illustrating a conventional interface nitriding process. [Figure 2] 1 is an operational flow diagram illustrating a process for forming a thin film using a technique for nitriding an interface using high-concentration radicals according to an embodiment of the present invention. [Figures 3a-3d] 2A and 2B are diagrams showing the configuration of a thin film corresponding to each step of forming a thin film according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. In order to clearly explain the present invention in the drawings, parts that are not relevant to the description are omitted, and similar parts are designated by similar reference numerals throughout the specification.

[0028] Throughout this specification, when a part is said to be "coupled" to another part, this includes not only when they are "directly coupled" to each other, but also when they are "electrically coupled" to each other via another element in between.

[0029] Furthermore, when a part "comprises" a certain element, this does not mean that it excludes other elements, but that it may further include other elements, unless otherwise specified.

[0030] The following examples are provided to aid in understanding the present invention and are not intended to limit the scope of the present invention. Therefore, inventions that perform the same function as the present invention and have the same scope also fall within the scope of the present invention.

[0031] As defined in the following specification of the present invention, a thin film or deposition may refer to a process of thinly coating an oxide or metal on a wafer (substrate) surface by alternately adsorbing and replacing molecules during semiconductor manufacturing. Therefore, each process described in the following specification may be performed using a radical unit or deposition device, and the thin film or deposition may be realized through techniques such as atomic layer deposition (ALD) or chemical vapor deposition (CVD).

[0032] FIG. 2 is a process flow diagram illustrating a process for forming an oxide film capable of effectively controlling the N concentration by solving the problems of the conventional deposition technique according to an embodiment of the present invention.

[0033] Referring to FIG. 2, a first thin film 110 made of a nitride film can be deposited on a substrate 100 using a deposition apparatus (S110).

[0034] At this time, the deposition device is a device that performs either CVD or ALD, and the deposition of the first thin film 110 can be performed using the corresponding technique.

[0035] In this case, as an alternative embodiment, as shown in FIG. 3a, the first thin film 110 deposited on the substrate 100 may be made of SiN, and the nitride oxide film 130 described later may be made of SiON.

[0036] Next, as shown in FIG. 3b, OH radicals (120) are injected onto the first thin film (110) to form an oxynitride film (130) in the first thin film (110) (S120).

[0037] If the first thin film 110 in step S110 is made of SiN as shown in FIG. 3b, the SiN can react with the OH radicals 120 to form SiON in step S120.

[0038] Specifically, the present invention sprays OH radicals (120) onto SiN at a high concentration, allowing the OH radicals (120) to penetrate into the thin film. After the OH radicals (120) penetrate into the thin film, they do not break the atomic bonds of SiN and react, but rather react with each other to form new compounds such as SiO and SiON. This has the advantage of being able to form SiO and SiON at relatively low temperatures of 480-730°C, rather than the conventional high-temperature heat treatment.

[0039] At this time, the oxynitride film 130 can be characterized by a lower SiON concentration in the lower portion 131 than in the upper portion 132, as shown in Figure 3c. This is because SiON is formed by the penetration and reaction of OH radicals, so the SiON concentrations in the upper portion 132 and lower portion 131 of the oxynitride film 130 are different. However, SiO components may remain in addition to SiON in the oxynitride film 130, and the SiO concentration may be higher in the lower portion 131 than in the upper portion 132 of the oxynitride film 130.

[0040] In addition, the process of injecting OH radicals (120) from step (S120) can be carried out at a process temperature between 480 and 730° C. Since the process is carried out at such a low temperature, it does not significantly affect the durability of the substrate, thin film, and other equipment.

[0041] Meanwhile, by selectively repeating steps S110 and S120, it is possible to adjust either the thickness of the first thin film 110 or the concentration of N within the first thin film 110. Also, after forming a thick SiN film, the concentration of SiO or SiON within the thin film can be adjusted by adjusting the concentration of OH radicals 120. Generally, SiN is not oxidized to SiON simply by heat, but by using OH radicals 120, oxidation can be induced even at low temperatures.

[0042] By repeating this process, SiON can be formed to the desired thickness and the desired N concentration can be adjusted. Generally, the N concentration in the interface layer between SiO2 (140) and the substrate (100) must be above a certain level. However, the process of the present invention makes it possible to precisely control the N concentration in the interface layer to a certain level, so that no N is added to SiO2 (140) and only the desired interface layer is added.

[0043] Finally, an insulating film may be formed on the first thin film (110) (S130).

[0044] As shown in FIG. 3d, this completes the thin film formation process by forming an insulating film made of SiO2 (140) on the oxynitride film (130) made of SiON.

[0045] At this time, steps S110 to S130 may be included in the process of forming a gate oxide film in the process of forming a semiconductor device.

[0046] Therefore, the process disclosed above improves the incomplete bonding between the substrate (100) interface and the SiN thin film, which is oxidized by high-density radicals, thereby improving conventional interface defects and thin film characteristics. Furthermore, SiN is difficult to oxidize using conventional processes due to its high-energy bonds. However, the process of the present invention oxidizes SiN by controlling the density of radicals through low-temperature oxidation and gas flow rate control, and by controlling the exposure time and amount of high-density radicals, thereby adjusting the N concentration and SiON thickness. Additionally, after SiN is deposited using the process of the present invention, OH radicals can be injected and a subsequent heat treatment can be performed, or SiON can be formed at the interface using an ALD technique.

[0047] The above description of the present invention is for illustrative purposes only, and those skilled in the art will understand that the present invention can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. Therefore, the above-described embodiments should be understood as illustrative in all respects and not restrictive. For example, each component described as a single component can be implemented in a distributed form, and similarly, each component described as distributed can be implemented in a combined form.

[0048] The scope of the present invention is indicated by the claims below rather than the above detailed description, and all modifications and variations derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention.

Claims

1. A method for forming an oxide film using a deposition apparatus, comprising: (a) depositing a first thin film made of a nitride film on a substrate; (b) spraying OH radicals onto the first thin film to oxidize the first thin film, thereby forming an oxynitride film within the first thin film; (c) forming an insulating film on the first thin film; A method for forming an oxide film using a deposition apparatus, wherein steps (a) and (b) are selectively repeated to adjust either the thickness of the first thin film or the concentration of N in the first thin film.

2. The step (a) 10. The method for producing an oxide film using the deposition apparatus of claim 1, wherein the deposition of the first thin film is performed based on either a CVD or ALD technique.

3. 2. The method for forming an oxide film using a deposition apparatus according to claim 1, wherein the first thin film is made of SiN, and the nitride oxide film is made of SiON.

4. 2. The method of forming an oxide film using a deposition apparatus according to claim 1, wherein, when the first thin film is made of SiN, in step (b), the SiN reacts with OH radicals to form SiON.

5. 2. The method for forming an oxide film using the deposition apparatus according to claim 1, wherein the concentration of the SiON component in the lower part of the nitride oxide film is lower than the concentration of the SiON component in the upper part of the nitride oxide film.

6. 10. The method for forming an oxide film using a deposition apparatus according to claim 1, wherein the step (b) of injecting OH radicals is performed at a process temperature of 480 to 730 degrees.

7. 10. The method for forming an oxide film using a deposition apparatus according to claim 6, wherein steps (a) to (c) are included in a process of forming a gate oxide film in a process of forming a semiconductor device.

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