Thin film generation method employing technology utilizing high-density radical nitriding interface

Abstract

According to one embodiment of the present invention, the present invention provides a method for generating an oxide film using a deposition apparatus, comprising: a step (a) for depositing a first thin film comprising a nitride film on a substrate; (b) oxidizing the first thin film by spraying OH radicals onto the first thin film, thereby forming a nitrogen oxide film in the first thin film; and (c) forming an insulating film on the first thin film. The thickness of the first thin film or the concentration of nitrogen inside the first thin film can be adjusted by selectively repeating the steps (a) and (b).

Description

Technical Field

[0001] The present invention relates to a method for generating a thin film, and in particular to a method for generating a thin film by utilizing high-density free radicals to nitride an interface. Background Art

[0002] As technology advances, semiconductors, which are the basis of the core technologies of the fourth industrial revolution, such as artificial intelligence, big data, 5G, and self-driving cars, require multilayer structures and complex circuit patterns in order to increase the speed of non-memory (system LSI) devices and the capacity of memory (DRAM, 3D_VNAND).

[0003] Therefore, at present, the semiconductor patterning technology with a line width of less than 5nm is ensured by introducing technologies such as extreme ultraviolet (EUV), but it is necessary to solve problems such as uneven film thickness, poor deposition of high aspect ratio contact holes, and low step coverage caused by the limitations of existing thin film deposition technology.

[0004] In this case, in order to solve the above problem, the existing thin film formation technology forms an oxide film by oxidizing the substrate or depositing it on the substrate, and then treats nitrous oxide (N2O) or nitric oxide (NO) to allow nitrogen (N) to penetrate into the interface, thereby reducing interface defects. As a result, the characteristics and reliability of the interface can be improved through such technology.

[0005] However, the above-mentioned conventional technologies have environmental problems due to the use of toxic gases, difficulty in adjusting the nitrogen concentration in the nitride film, and problems such as deterioration of interface roughness due to high temperature treatment, thereby deteriorating electrical characteristics.

[0006] Figure 1 This is a diagram showing an example of a conventional interface nitridation process.

[0007] The existing interface nitridation technology adopts a method of oxidizing the substrate 100 or forming an oxide film on the substrate 100 by deposition, and then performing a heat treatment using a nitrogen-containing gas.

[0008] Specifically, existing technologies such as Figure 1 As shown in parts (a) and (b) of FIG. 1 , an oxide film may be formed by oxidation or deposition on the substrate 100, and annealing may be performed using a gas containing nitrogen (e.g., nitrous oxide, nitric oxide, etc.). In this case, if annealing is excessively performed to increase the nitrogen concentration, the nitrogen concentration of not only the interface between the substrate 100 and silicon dioxide (SiO2) but also the silicon dioxide itself increases, thereby reducing the characteristics of the semiconductor device.

[0009] On the other hand, Figure 1 As shown in part (a) of FIG. 1 , if only an oxide film is formed, interface defects occur due to incomplete bonds such as dangling bonds at the silicon dioxide interface between the substrates 100 , thereby having a high interface defect density, such as Figure 1 As shown in part (b) of FIG. 1 , when annealing is performed using a gas containing nitrogen, interface defects such as incomplete bonding such as dangling bonds between the substrate 100 and the interface are improved. In this case, in addition to nitrogen, oxygen (O) or hydrogen (H) may be used depending on the process or material.

[0010] In addition, the existing technology forms silicon oxynitride (SiON) by breaking the atomic bonds of silicon dioxide, and considerable energy is required to break the bonds between atoms. Therefore, in the existing post-processing process, a high-temperature heat treatment method or plasma treatment method at more than 900°C is used to break the bonds between atoms.

[0011] In this case, the plasma method has the disadvantage of using too much energy, which may adversely affect the durability of the semiconductor product or the durability of the deposition equipment itself. In addition, the existing thermal treatment method also has similar disadvantages due to the process of performing too high a temperature. Generally, the plasma method uses more energy than the thermal treatment method, so the plasma method is used when the desired thin film deposition cannot be performed by the thermal treatment method.

[0012] Furthermore, the existing technology cannot react with nitrogen when the concentration of molecules converted into silicon oxynitride exceeds a specified level by reacting with nitrogen by breaking the atomic bonds of silicon dioxide, and therefore requires injection of higher energy. In this case, the nitrogen concentration in the silicon dioxide itself at the interface between the substrate and silicon dioxide is not increased, but there are limitations in adjusting the nitrogen concentration and the thickness of the silicon oxynitride, resulting in the problem of difficulty in improving device characteristics. Summary of the invention

[0013] Technical issues The present invention is to solve the problems of the prior art mentioned above. According to one embodiment of the present invention, the purpose of the present invention is to improve the interface defects and the characteristics of the film by improving the incomplete bonding between the interface of the substrate and the interface of the silicon nitride (SiN) film oxidized by high-density free radicals.

[0014] Furthermore, another object of the present invention is that, generally, silicon nitride is difficult to oxidize due to high-energy bonding, but the density of free radicals can be controlled by low-temperature oxidation (480-730°C) and adjustment of gas flow rate, and silicon nitride can be oxidized by controlling the exposure time and exposure amount of high-density free radicals, thereby adjusting the nitrogen concentration and the thickness of silicon oxynitride.

[0015] However, the technical problems to be solved by this embodiment are not limited to the technical problems mentioned above, and there may also be other technical problems.

[0016] Technical Solution As a technical means for solving the above-mentioned technical problems, the present invention provides a method for generating an oxide film using a deposition device, comprising: step (a), depositing a first thin film composed of a nitride film on a substrate; step (b), oxidizing the first thin film by spraying OH radicals onto the first thin film, thereby forming a nitride oxide film in the first thin film; and step (c), forming an insulating film on the first thin film, and either the thickness of the first thin film or the concentration of nitrogen inside the first thin film can be adjusted by selectively repeating the steps (a) and (b).

[0017] Furthermore, in the step (a), the deposition of the first thin film may be performed based on any one of chemical vapor deposition (CVD) and atomic layer deposition (ALD).

[0018] Furthermore, the first thin film may be made of silicon nitride, and the oxynitride film may be made of silicon oxynitride.

[0019] Furthermore, when the first thin film is made of silicon nitride, in the step (b), the silicon nitride may react with OH radicals to form silicon nitride oxide.

[0020] Also, the concentration of the silicon oxynitride component in the lower portion of the oxynitride film may be lower than the concentration of the silicon oxynitride component in the upper portion of the oxynitride film.

[0021] Furthermore, the process of injecting OH radicals in step (b) may be performed at a process temperature between 480°C and 730°C.

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

[0023] Beneficial Effects According to one embodiment of the present invention, the present invention aims to improve interface defects and film characteristics by improving the incomplete bonding between the interface of the substrate and the interface of the silicon nitride film oxidized by high-density radical oxidation.

[0024] Furthermore, another object of the present invention is that, generally, silicon nitride is difficult to oxidize due to high-energy bonding, but the density of free radicals can be controlled by low-temperature oxidation (480-730°C) and adjustment of gas flow rate, and silicon nitride can be oxidized by controlling the exposure time and exposure amount of high-density free radicals, thereby adjusting the nitrogen concentration and the thickness of silicon oxynitride.

[0025] Based on this, OH radicals may be injected after silicon nitride is deposited for subsequent heat treatment, or silicon oxynitride may be formed at the interface by atomic layer deposition. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a diagram showing an example of a conventional interface nitridation process.

[0027] Figure 2 FIG. 1 is a flowchart showing an operation of a thin film growth process using a technique of using high concentration radicals to nitride an interface according to an embodiment of the present invention.

[0028] Figure 3a to Figure 3d FIG. 4 is a diagram showing the morphology of a thin film corresponding to each step of forming a thin film according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that a person skilled in the art can easily implement the present invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Moreover, in order to clearly illustrate the present invention in the accompanying drawings, parts not related to the description will be omitted, and similar parts will be given similar reference numerals throughout the specification.

[0030] Throughout the specification, when it is mentioned that a part is "connected" to other parts, it not only refers to the case of "direct connection", but also includes the case of "indirect connection" with other devices between them. In addition, when it is mentioned that a part "includes" a certain structural element, unless there is a special record to the contrary, it means that other structural elements may also be included, rather than excluding other structural elements.

[0031] The following embodiments are detailed descriptions for helping the understanding of the present invention, but are not intended to limit the scope of the present invention. Therefore, inventions having the same scope and the same functions as the present invention should also fall within the scope of the present invention.

[0032] The thin film or deposition defined in the following description of the present invention may refer to a process of thinly coating an oxide or metal by alternately adsorbing and replacing molecules on the surface of a wafer (substrate) in a semiconductor manufacturing process. Therefore, each process described in the following description may be performed by a radical unit or a deposition device, and the thin film or deposition may be achieved by techniques such as atomic layer deposition or chemical vapor deposition.

[0033] Figure 2 A flowchart showing a process of forming an oxide film that can effectively adjust the nitrogen concentration and solve the problems of the existing deposition technology according to an embodiment of the present invention.

[0034] Reference Figure 2, a first thin film 110 composed of an oxide film may be deposited on the substrate 100 by using a deposition device (step S110 ).

[0035] In this case, the deposition device is a device that performs any one of chemical vapor deposition and atomic layer deposition techniques, and the first film 110 can be deposited using the relevant techniques.

[0036] In this case, as an alternative embodiment, Figure 3a As shown, the first thin film 110 first deposited on the substrate 100 may be composed of silicon nitride, and the oxynitride film 130 described later may be composed of silicon oxynitride.

[0037] Then, if Figure 3b As shown, the oxynitride film 130 may be formed in the first thin film 110 by spraying OH radicals 120 into the first thin film 110 (step S120 ).

[0038] like Figure 3b As shown, in the case where the first thin film 110 is made of silicon nitride in step S110 , the silicon nitride may react with the OH radical 120 to form silicon nitride oxide in step S120 .

[0039] Specifically, the present invention can spray OH radicals 120 at a high concentration on silicon nitride, so that the OH radicals 120 can penetrate into the film. In this case, after the OH radicals 120 penetrate into the film, they do not react by breaking the atomic bonds of silicon nitride, but can react with silicon nitride and OH to form silicon monoxide (SiO) or a new compound called silicon oxynitride. As a result, the existing high-temperature heat treatment is eliminated, and in the above process, silicon monoxide or silicon oxynitride can be formed at a lower temperature of 480 to 730°C.

[0040] In this case, if Figure 3c As shown, the oxynitride film 130 may have a characteristic that the concentration of the silicon oxynitride component in the lower portion 131 of the oxynitride film 130 is lower than the concentration of the silicon oxynitride component in the upper portion 132. This is because, as OH radicals penetrate and react to form silicon oxynitride, the concentrations of silicon oxynitride in the upper portion 132 and the lower portion 131 of the oxynitride film 130 are different from each other, and on the other hand, in addition to silicon oxynitride, a silicon monoxide component may remain in the oxynitride film 130, and in the oxynitride film 130, the concentration of the silicon monoxide component in the lower portion 131 may be higher than that in the upper portion 132.

[0041] Furthermore, in step S120 , the process of injecting OH radicals 120 may be performed at a process temperature between 480° C. and 730° C. Performing the process at such a low temperature will not have a significant impact on the durability of the substrate, the film, or other devices.

[0042] On the other hand, by selectively repeating step S110 and step S120, it is possible to adjust the thickness of the first film 110 or the concentration of nitrogen in the first film 110. Furthermore, when the concentration of OH radicals 120 is adjusted after forming a thick silicon nitride, the concentration of silicon monoxide or silicon oxynitride in the film can be adjusted. Generally, silicon nitride cannot be oxidized to silicon oxynitride by heat alone, but oxidation can be induced even at low temperatures by using OH radicals 120.

[0043] By repeating the relevant process, silicon oxynitride of a desired thickness can be formed, and a desired nitrogen concentration can be adjusted. In this case, the nitrogen concentration of the interface layer between silicon dioxide 140 and substrate 100 should generally be sufficient to be above a prescribed level. However, the process of the present invention can precisely adjust the nitrogen concentration of the interface layer to a prescribed level, and even if nitrogen is not applied to silicon dioxide 140 at all, nitrogen can be applied only to a desired interface layer.

[0044] Finally, an insulating film may be formed on the first thin film 110 (step S130 ).

[0045] like Figure 3d As shown, the thin film formation process can be completed by forming an insulating film composed of silicon dioxide 140 on the oxynitride film 130 composed of silicon oxynitride.

[0046] In this case, step S110 to step S130 may be included in a process of forming a gate oxide film in forming a semiconductor device.

[0047] Therefore, the incomplete bonding between the interface of the substrate 100 and the interface of the silicon nitride film oxidized by high-density free radicals can be improved by the above-described process, thereby improving the existing interface defects and the characteristics of the film. In addition, silicon nitride is difficult to be oxidized by the existing process due to high-energy bonding, but the density of free radicals can be controlled by the process of the present invention through low-temperature oxidation and adjustment of gas flow, and silicon nitride can be oxidized based on controlling the exposure time and exposure amount of high-density free radicals, thereby adjusting the nitrogen concentration and the thickness of silicon oxynitride. In addition, OH free radicals can be injected after silicon nitride is deposited through the process of the present invention for subsequent heat treatment, or silicon oxynitride can be formed at the interface by atomic layer deposition technology.

[0048] The above description of the present invention is only for illustration, and it can be understood by those skilled in the art that the present invention can be easily changed to other specific forms without changing the technical ideas or essential features of the present invention. Therefore, no matter from which aspect, the above embodiments are only for illustration and should not be interpreted as limiting. For example, each structural element described in a single type can also be implemented in a dispersed manner, and similarly, the structural elements described in a dispersed manner can be implemented in a combined form.

[0049] The scope of the present invention is shown in the attached claims for protection compared to the detailed description thereof, and the meaning and scope of the claims for protection and all changes or deformations derived from equivalent concepts should be interpreted as being included in the scope of the present invention.

Claims

1. A method for generating an oxide film using a deposition device, characterized in that: include: Step (a), depositing a first thin film consisting of a nitride film on a substrate; Step (b), oxidizing the first film by spraying OH radicals toward the first film, thereby forming an oxynitride film in the first film; as well as Step (c), forming an insulating film on the first thin film, By selectively repeating the steps (a) and (b), either the thickness of the first thin film or the concentration of nitrogen in the first thin film is adjusted.

2. The method for forming an oxide film using a deposition device according to claim 1, characterized in that: In the step (a), the deposition of the first thin film is performed based on any one of chemical vapor deposition and atomic layer deposition techniques.

3. The method for forming an oxide film using a deposition device according to claim 1, characterized in that: The first thin film is composed of silicon nitride, and the oxynitride film is composed of silicon oxynitride.

4. The method for forming an oxide film using a deposition device according to claim 1, characterized in that: In the case where the first thin film is made of silicon nitride, in the step (b), the silicon nitride reacts with OH radicals to form silicon nitride oxide.

5. The method for forming an oxide film using a deposition device according to claim 1, characterized in that: The concentration of the silicon oxynitride component in the lower portion of the oxynitride film is lower than the concentration of the silicon oxynitride component in the upper portion of the oxynitride film.

6. The method for forming an oxide film using a deposition device according to claim 1, characterized in that: The process of spraying the OH radicals in the step (b) is performed at a process temperature between 480° C. and 730° C.

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

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