A thin film fabrication method that applies a technique to nitride the interface using high-density radicals.

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 forming a thin film, and more specifically, to a method for forming a thin film that nitrides an interface using high-density radicals.

Background Art

[0002] With the development of technology, semiconductors, which are the core of the key technologies of the fourth industrial revolution such as artificial intelligence, big data, 5G, and autonomous driving vehicles, require multilayer structures and complex-shaped circuit patterns for improving the speed of non-memory (System LSI) devices and increasing the capacity of memory (DRAM, 3D_VNAND).

[0003] Along with this, currently, through the introduction of technologies such as EUV (Extreme Ultraviolet), semiconductor patterning technology with a line width of 5 nm or less is ensured, but problems such as non-uniformity of thin film thickness, poor deposition of High Aspect Ratio Contact Hole, and low step coverage, which have emerged as the limitations of existing thin film deposition technologies, must be solved. <氧>

[0004] At this time, in order to solve the above-mentioned problems, the conventional thin film formation technology oxidized the substrate or formed an oxide film by depositing on the substrate, and then treated with N2O or NO to penetrate N to the interface to reduce the defects of the interface. As a result of such technology, it was possible to achieve the result of improving the characteristics and reliability of the interface.

[0005] However, such conventional technologies also have problems such as environmental problems due to toxic gases, difficulty in adjusting the N concentration in the nitride film, and deterioration of electrical characteristics due to deterioration of the roughness of the interface by performing high-temperature treatment.

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

[0007] It should be noted that there is an unclear symbol "<氧>" in the original text at line 18 which is retained as is in the translation. If this is an error, please correct the original text for a more accurate translation.Conventional interfacial nitriding technology applied a method in which an oxide film was formed by oxidizing or depositing an oxide film onto the substrate (100), and then heat-treated using a gas containing nitrogen. Specifically, conventional techniques, as illustrated in Figures 1(a) and 1(b), can be used to form an oxide film on a substrate (100) by oxidation or deposition, and then perform annealing using a gas containing nitrogen (for example, nitrogen dioxide (N2O), nitrogen oxide (NO), etc.).

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

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

[0010] Furthermore, conventional techniques break the atomic bonds of SiO2 to form SiON, which requires considerable energy to break the interatomic bonds. Therefore, conventional post-processing methods utilize high-temperature heat treatment methods of 900°C or higher or plasma treatment methods to break the interatomic bonds.

[0011] At this time, the plasma method has the disadvantage of negatively affecting the durability of semiconductor products or the deposition equipment itself because it utilizes extremely high energy. Similarly, conventional heat treatment methods also suffer from similar disadvantages due to their high-temperature processes. Generally, since the plasma method utilizes higher energy than the heat treatment method, it is used when the desired thin-film deposition cannot be achieved through the heat treatment method.

[0012] Furthermore, conventional technology involves breaking the atomic bonds of SiO2. When the concentration of molecules converted to SiON by reacting with N exceeds a certain level, the reaction with N ceases, requiring injection at a higher energy level. At this point, the N concentration increases in the SiO2 itself, not just at the substrate-SiO2 interface, leading to a problem where improving device characteristics becomes difficult due to the limitations of adjusting N concentration and SiON thickness. [Overview of the project] [Problems that the invention aims to solve]

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

[0014] Furthermore, although SiN is generally bonded with high energy and difficult to oxidize, low-temperature oxidation (480-730°C) and gas flow rate control allow for the control of radical density, exposure time and amount of high-density radicals, and thus the oxidation of SiN is used to adjust the N concentration and SiN thickness for another purpose.

[0015] However, the technical challenges that this embodiment aims to address are not limited to those described above, and other technical challenges may exist. [Means for solving the problem]

[0016] As a technical means to achieve the aforementioned technical challenges, a method for generating an oxide film using a deposition apparatus includes the steps of (a) depositing a first thin film composed of a nitride film onto a substrate, (b) injecting OH radicals into the first thin film to oxidize the first thin film and form a nitrogen oxide film within the first thin film, and (c) forming an insulating film on the first thin film. By selectively repeating steps (a) and (b), either the thickness of the first thin film or the concentration inside the first thin film is adjusted.

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

[0018] Also, the first thin film can be composed of SiN, and the silicon nitride film can be composed of SiON.

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

[0020] Also, the concentration of the SiON component in the lower part of the silicon nitride film can be lower than the concentration of the SiON component in the upper part of the silicon nitride film.

[0021] Also, the process in which OH radicals are injected in step (b) can proceed at a process temperature between 480 and 730 °C.

[0022] Also, steps (a) to (c) can be included in the process of forming a gate oxide film during the process of forming a semiconductor element.

Advantages of the Invention

[0023] According to one embodiment of the present invention, it is an object to improve the imperfect bonding between the interface of the substrate and the interface of the SiN thin film oxidized by high-density radicals, and to improve the interface defects and the characteristics of the thin film.

[0024] Also, generally, SiN is bonded with high energy and is difficult to oxidize. However, by controlling the density of radicals through low-temperature oxidation (480 to 730 °C) and adjustment of gas flow rate, and controlling the exposure time and exposure amount of high-density radicals, another object is to oxidize SiN to adjust the N concentration and the thickness of SiON.

[0025] Based on this, after SiN is deposited, OH radicals can be injected to perform subsequent heat treatment, or SiON can be formed on the interface by the ALD method.

Brief Description of the Drawings

[0026] [Figure 1] It is an exemplary drawing showing a conventional interface nitriding process. [Figure 2] It is an operation flowchart showing a process of forming a thin film to which a technique of nitriding an interface using high-concentration radicals is applied according to an embodiment of the present invention. [Figures 3a-3d] It is a drawing of the form of a thin film corresponding to each step of forming a thin film according to an embodiment of the present invention.

Best Mode for Carrying Out the Invention

[0027] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those having ordinary knowledge in the technical field to which the present invention pertains can easily implement it. However, the present invention can be embodied in various different forms and is not limited to the embodiments described here. And, in order to clearly explain the present invention in the drawings, parts not related to the explanation are omitted, and similar reference numerals are given to similar parts throughout the specification.

[0028] Throughout the specification, when a part is said to be "connected" to another part, this includes not only the case where it is "directly connected", but also the case where it is "electrically connected" with other elements interposed therebetween. [[ID=!]]

[0029] Also, when a part is said to "include" a certain component, this means that, unless otherwise stated to the contrary, it does not exclude other components, but can further include other components.

[0030] The following embodiments are detailed explanations for helping the understanding of the present invention and do not limit the scope of rights of the present invention. Therefore, inventions within the same scope that perform the same function as the present invention will also belong to the scope of rights of the present invention.

[0031] In the following specification of the present invention, a thin film or deposition can refer to a process in which an oxide or metal is thinly coated onto the surface of a wafer (substrate) by alternately adsorbing and substituting molecules during the semiconductor manufacturing process. Thus, each of the processes described in the following specification can be carried out by a radical unit or deposition apparatus, and the thin film or deposition can be realized through technologies such as atomic layer deposition (ALD) or chemical vapor deposition (CVD).

[0032] Figure 2 is a process flow diagram showing the process of generating an oxide film that can effectively adjust the concentration of nitrogen, solving the problems of conventional deposition techniques, according to one embodiment of the present invention.

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

[0034] At this time, the deposition apparatus is one that performs either CVD or ALD techniques, and the deposition of the first thin film (110) can be carried out using the relevant technique.

[0035] In this case, as shown in Figure 3a as a selective embodiment, the first thin film (110) deposited on the substrate (100) for the first time may be composed of SiN, and the nitrogen oxide film (130), which will be described later, may be composed of SiON.

[0036] Next, as shown in Figure 3b, OH radicals (120) can be injected into the first thin film (110) to form a nitrogen oxide film (130) within the first thin film (110) (S120).

[0037] If the first thin film (110) in step (S110) is composed of SiN as shown in Figure 3b, then in step (S120), the SiN can react with the OH radical (120) to form SiN.

[0038] Specifically, the present invention involves spraying OH radicals (120) onto SiN at a high concentration, allowing the OH radicals (120) to penetrate into the thin film. At this time, after the OH radicals (120) penetrate into the thin film, instead of breaking the atomic bonds of SiN and reacting, SiN and OH react with each other to form new compounds such as SiO and SiON. This eliminates the need for conventional high-temperature heat treatment, and the process has the advantage of being able to form SiO and SiON at relatively low temperatures of 480-730°C.

[0039] At this time, the nitrogen oxide film (130) can have the characteristic that the concentration of the SiON component in the lower part (131) is lower than the concentration of the SiON component in the upper part (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 part (132) and lower part (131) of the nitrogen oxide film (130) will differ from each other. On the other hand, in addition to SiON, SiO components may also remain in the nitrogen oxide film (130), and the concentration of SiO components may be even higher in the lower part (131) of the nitrogen oxide film (130) than in the upper part (132).

[0040] Furthermore, the process in which OH radicals (120) are injected from stage (S120) can be carried out at a process temperature between 480 and 730°C. By carrying out the process at such a low temperature, it does not have a significant impact on the durability of the substrate, thin film, and other equipment.

[0041] On the other hand, by selectively repeating steps (S110) and (S120), either the thickness of the first thin film (110) or the concentration of N inside the first thin film (110) can be adjusted. Furthermore, if the concentration of OH radicals (120) is adjusted after forming a thick SiN film, the concentrations of SiO and SiON inside the thin film can be adjusted. Generally, SiN is not oxidized by SiON simply by heat, but by utilizing OH radicals (120), oxidation can be induced even at low temperatures.

[0042] When the relevant process is performed repeatedly, it becomes possible to form SiON of the desired thickness and adjust the desired N concentration. In this case, the N concentration of the interface layer between SiO2(140) and the substrate (100) must generally be above a certain level. However, the process of the present invention makes it possible to precisely control the N concentration of the interface layer to a certain level, so that no N is applied to SiO2(140) and N is applied only to the desired interface layer.

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

[0044] As shown in Figure 3d, this process of forming a thin film is completed by forming an insulating film composed of SiO2 (140) on top of a nitrogen oxide film (130) composed of SiON.

[0045] At this time, step (S110) or step (S130) can be included in the process of forming the gate oxide film within the process of forming the semiconductor device.

[0046] Therefore, the imperfect bonding of the interface between the substrate (100) and the SiN thin film oxidized by high-density radicals is improved through the process disclosed above, thereby improving conventional interface defects and thin film properties. Furthermore, although SiN is bonded at high energy and difficult to oxidize in conventional processes, the process of the present invention allows for the oxidation of SiN and adjustment of N concentration and SiN thickness based on low-temperature oxidation, control of radical density through gas flow rate adjustment, and control of exposure time and amount of high-density radicals. In addition, after SiN is deposited through the process of the present invention, OH radicals can be injected to perform subsequent heat treatment, or SiN can be formed at the interface through ALD techniques.

[0047] The above description of the present invention is illustrative, and a person with ordinary skill in the art will understand that the invention can be easily modified into other specific forms without altering the technical idea or essential features. Therefore, the embodiments described above should be understood in all respects as illustrative and not limiting. For example, each component described as a single type can be implemented in a distributed manner, and similarly, components described as distributed can be implemented in a combined form.

[0048] The scope of the present invention is defined by the claims, which are set forth below rather than in the detailed description above, and all modified or altered forms derived from the meaning and scope of the claims and the concept of equivalents thereof should be interpreted as being included within the scope of the present invention.

Claims

1. In a method for generating an oxide film using a vapor deposition apparatus, (a) A step of depositing a first thin film made of a nitride film onto a substrate, (b) A step of forming a nitrogen oxide film within the first thin film by injecting OH radicals into the first thin film and oxidizing the first thin film, (c) The step of forming an insulating film on the first thin film, A method for producing an oxide film using a vapor deposition apparatus, wherein the thickness of the first thin film or the concentration of N inside the first thin film is adjusted by selectively repeating steps (a) and (b) described above.

2. The aforementioned step (a) is A method for producing an oxide film using the deposition apparatus according to claim 1, wherein the first thin film is deposited based on either a CVD or ALD technique.

3. A method for producing an oxide film using the deposition apparatus according to claim 1, wherein the first thin film is composed of SiN and the nitrogen oxide film is composed of SiON.

4. A method for producing an oxide film using the deposition apparatus according to claim 1, wherein, in the first thin film, the SiN reacts with an OH radical in step (b) to form SiON.

5. A method for producing an oxide film using the deposition apparatus according to claim 1, wherein the concentration of the SiON component in the lower part of the nitrogen oxide film is lower than the concentration of the SiON component in the upper part of the nitrogen oxide film.

6. A method for producing an oxide film using the deposition apparatus according to claim 1, wherein the step of injecting OH radicals in step (b) is carried out at a process temperature between 480 and 730°C.

7. A method for generating an oxide film using the deposition apparatus according to claim 6, wherein 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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