An antireflection composite film, a semiconductor device, and a method for manufacturing the same

Abstract

An antireflection composite film for photolithography, which comprises at least one layer of nitrogen-containing antireflection film and at least one layer of nitrogen-free antireflection film. By optimizing the antireflection coating under the photoresist, the properties of the antireflection coating are improved, the light reflection and scattering during photolithographic patterning are significantly reduced, the accuracy of the pattern shape formed by photolithography is improved, which helps to manufacture fine patterns, and finally improves the integration of components.

Description

Technical Field

[0001] The exemplary embodiments of the present invention relate to an anti-reflective composite film, a semiconductor device, and a method for preparing the same. Background Technology

[0002] Photolithography is one of the most critical technologies in the manufacturing of semiconductors, flat panel displays, and other devices. With increasing semiconductor integration, the aspect ratio of semiconductor devices is increasing, their structures are becoming more complex, and the patterns formed by photolithography are gradually shrinking. To ensure device performance, miniaturizing the patterns formed by photolithography is a major technological development direction for photolithography, namely, improving pattern resolution. Improvements in semiconductor capacity and performance can be achieved through pattern miniaturization. Summary of the Invention

[0003] According to one or more embodiments, an antireflective composite film for photolithography is provided, the antireflective composite film comprising at least one nitrogen-containing antireflective film and at least one nitrogen-free antireflective film.

[0004] This invention improves the characteristics of the anti-reflective coating by optimizing the anti-reflective coating under the photoresist, which can significantly reduce light reflection and scattering during photolithography patterning, improve the accuracy of the pattern shape formed by photolithography, and thus help to manufacture fine patterns, ultimately improving the integration of components.

[0005] According to one or more embodiments, a method for preparing an anti-reflective composite film includes the following steps:

[0006] Forming a nitrogen-containing antireflective film;

[0007] A nitrogen-free antireflective film is formed on a nitrogen-containing antireflective film.

[0008] According to one or more embodiments, a method for fabricating a semiconductor device includes the following steps:

[0009] The anti-reflective composite film as described above is coated onto the layer to be patterned;

[0010] Photoresist is coated onto the anti-reflective composite film;

[0011] Place the photomask above the photoresist and irradiate the photomask with an exposure source;

[0012] Pattern the patterned layer. Attached Figure Description

[0013] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0014] Figure 1 A schematic diagram of the photolithography process in the prior art is shown.

[0015] Figure 2 A schematic diagram of the photolithography process according to an embodiment of the present invention is shown.

[0016] Figure 3 A schematic diagram of the preparation process of the anti-reflective composite film according to an embodiment of the present invention is shown.

[0017] [Symbol Explanation]

[0018] [Existing Technology]

[0019] 10-Patterned layer; 11-Anti-reflective coating; 12-Photoresist; 13-Mask;

[0020] [This Invention]

[0021] 20 - Patterning layer; 21 - Anti-reflective composite film; 211 - Nitrogen-containing anti-reflective film; 212 - Nitrogen-free anti-reflective film; 22 - Photoresist; 23 - Mask. Detailed Implementation

[0022] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0023] The accompanying drawings illustrate various structural schematics according to embodiments of the present invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0024] In the context of this invention, when a layer / element is referred to as being "above" another layer / element, the layer / element may be directly above the other layer / element, or there may be an intermediate layer / element between them. Additionally, if a layer / element is "above" another layer / element in one orientation, then when the orientation is reversed, the layer / element may be "below" the other layer / element.

[0025] During photolithography, especially when the wavelength of the exposure light source becomes shorter, the influence of many optical phenomena becomes more and more obvious. For example, the light interference effect caused by reflected light on the patterned layer of the semiconductor substrate increases, resulting in a large difference between the pattern formed by photolithography and the design, which greatly reduces the accuracy of photolithography. In order to solve this technical problem, an anti-reflection coating is usually coated between the photoresist and the patterned layer. This can alleviate the light interference and scattering phenomena, making it easier to form patterns by photolithography and helping to form fine patterns.

[0026] Photolithography is a key technology in semiconductor device manufacturing. The quality of photolithography directly determines the capacity and performance of semiconductor devices. Therefore, as photolithographic patterns become more refined, the characteristics of the anti-reflective coating under the photoresist become particularly important. Figure 1 A schematic diagram of a photolithography process in the prior art is shown, involving photoresist and an underlying anti-reflective coating. (Example) Figure 1 As shown, an anti-reflective coating 11 is coated on the patterned layer 10, and a photoresist 12 is coated on the anti-reflective coating 11. A mask 13 is placed above the photoresist 12, and an exposure source irradiates the mask 13. The mask 13 has a semiconductor pattern.

[0027] exist Figure 1 In this process, the anti-reflective coating 11 typically uses a silicon-based SiON film, which is formed using SiH4 gas and N2O gas; or the anti-reflective coating 11 uses a SiOC film, which is formed using SiH4 gas and CO2 gas. Although using SiON or SiOC films in the anti-reflective coating 11 alleviates light interference and scattering to some extent, its effect is limited and cannot meet the precision requirements for forming fine patterns in current photolithography processes.

[0028] To further improve the ability to form fine patterns in photolithography, this invention employs an anti-reflective composite film when applying the anti-reflective coating. Figure 2 A schematic diagram of the photolithography process according to an embodiment of the present invention is shown, illustrating the anti-reflective composite film. For example... Figure 2 As shown, an anti-reflective composite film 21 is coated on the patterned layer 20, and photoresist 22 is coated on the anti-reflective composite film 21. A photomask 23 is placed above the photoresist 22. A laser or electron beam is used as the exposure source to irradiate the photomask 23. Light passes through the photomask 23 and irradiates the photoresist 22. The photoresist 22 is a photosensitive material, and its material properties change due to light exposure; that is, the solubility of the photoresist 22 changes. Through processes such as exposure, development, and etching, the semiconductor circuit pattern on the photomask 23 is transferred to the patterned layer 20, forming a geometric pattern completely corresponding to the photomask 23. The above process is the patterning process of the patterned layer 20, which is a method for fabricating semiconductor devices and can yield corresponding semiconductor devices.

[0029] exist Figure 2 In this process, the antireflective composite film 21 includes a nitrogen-containing antireflective film 211 and a nitrogen-free antireflective film 212. That is, the antireflective composite film 21 can be composed of multiple layers of film structure, including at least one nitrogen-containing antireflective film 211 and one nitrogen-free antireflective film 212. The nitrogen-containing antireflective film 211 in the antireflective composite film 21 can include multiple layers of different film structure, and the nitrogen-free antireflective film 212 in the antireflective composite film 21 can also include multiple layers of different film structure.

[0030] This invention improves the characteristics of the anti-reflective coating by optimizing the anti-reflective coating under the photoresist, which can significantly reduce light reflection and scattering during photolithography patterning, improve the accuracy of the pattern shape formed by photolithography, and thus help to manufacture fine patterns, ultimately improving the integration of components.

[0031] In a specific embodiment, the nitrogen-containing antireflective film 211 is a SiON film. The SiON film can be obtained by the following two methods: one is to form it using three gases, SiH4, NH3 and N2O; the other is to form it using two gases, SiH4 and N2O.

[0032] The nitrogen-free antireflective film 212 is a SiOC film or a SiOCH film. Preferably, the SiOC film is formed by two gases, SiH4 and CO2, and the SiOCH film is formed by three gases, SiH4, C3H8 and O2. The refractive index of the SiOCH film is in the range of 1 to 3.

[0033] The thickness of the nitrogen-free antireflective film 212 is 1 to 10 times that of the nitrogen-containing antireflective film 211, meaning the thickness ratio of the nitrogen-free antireflective film 212 to the nitrogen-containing antireflective film 211 is 1:1 to 1:10. This thickness ratio affects the reflectivity of the antireflective composite film 21. Therefore, the reflectivity of the antireflective composite film 21 can be controlled by adjusting this ratio, thus improving its applicability.

[0034] This invention also provides a method for preparing an anti-reflective composite film. The formation process of the anti-reflective composite film 21 will be described in detail below. The preparation steps of the anti-reflective composite film include the following:

[0035] Formation of a nitrogen-containing antireflective film 211;

[0036] A nitrogen-free antireflective film 212 is formed on the nitrogen-containing antireflective film 211.

[0037] It should be noted that the nitrogen-containing antireflective film 211 can be a single layer or multiple layers, and the nitrogen-free antireflective film 212 can be a single layer or multiple layers. Preferably, the antireflective composite film 21 is formed into a multilayer film structure using plasma-enhanced chemical vapor deposition (PECVD).

[0038] In the process of preparing the antireflective composite film 21, the reflectivity or reflection effect of the antireflective composite film 21 is controlled by adjusting the film thickness of the nitrogen-free antireflective film 212 and the nitrogen-containing antireflective film 211.

[0039] Example:

[0040] Figure 3 A schematic diagram illustrating the preparation process of the anti-reflective composite film according to an embodiment of the present invention is shown. Figure 3 As shown, a SiON film is formed using three gases: SiH4, NH3, and N2O. A SiOCH film is then deposited on the SiON film using a PECVD process. The SiOCH film is formed using three gases: SiH4, C3H8, and O2. The thickness of the SiOCH film is five times that of the SiON film.

[0041] This invention improves upon existing anti-reflective coatings by employing a multi-layered composite film structure. This improved coating characteristic significantly reduces light reflection and scattering during photolithography patterning, enhancing the accuracy of the pattern shape and facilitating the fabrication of fine patterns. Ultimately, this improves the integration density of components. Furthermore, the reflectivity of the anti-reflective composite film can be controlled by adjusting the thickness ratio of the nitrogen-containing and nitrogen-free anti-reflective films, thus improving its applicability.

[0042] The above description does not provide detailed explanations of the technical aspects of each layer's patterning, etching, etc. However, those skilled in the art should understand that various technical means can be used to form layers and regions of the desired shape. Furthermore, to form the same structure, those skilled in the art can also design methods that are not entirely identical to those described above. Additionally, although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination.

[0043] The embodiments of the present invention have been described above. However, these embodiments are merely illustrative and not intended to limit the scope of the invention. The scope of the invention is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of the invention, and all such substitutions and modifications should fall within the scope of the invention.

Claims

1. A method for preparing an anti-reflective composite film for photolithography, characterized in that, Includes the following steps: Forming a nitrogen-containing antireflective film; A nitrogen-free antireflective film is formed on the nitrogen-containing antireflective film; The nitrogen-free antireflective film comprises a SiOC film and / or a SiOCH film; the thickness of the nitrogen-free antireflective film is 5 to 10 times that of the nitrogen-containing antireflective film. The nitrogen-containing antireflective film includes a SiON film, which is formed by using three gases, SiH4, NH3 and N2O, or by using two gases, SiH4 and N2O. The SiOC membrane is formed using two gases, SiH4 and CO2, while the SiOCH membrane is formed using three gases, SiH4, C3H8, and O2. The reflectivity of the antireflective composite film is controlled by adjusting the thickness ratio of the nitrogen-free antireflective film and the nitrogen-containing antireflective film during the preparation process; the nitrogen-containing antireflective film and the nitrogen-free antireflective film are formed by plasma-enhanced vapor deposition.

2. An anti-reflective composite film for photolithography prepared by the method according to claim 1, characterized in that, The anti-reflective composite film comprises at least one nitrogen-containing anti-reflective film and at least one nitrogen-free anti-reflective film; The nitrogen-free antireflective film comprises a SiOC film and / or a SiOCH film; The thickness of the nitrogen-free antireflective film is 5 to 10 times that of the nitrogen-containing antireflective film.

3. The anti-reflective composite film according to claim 2, characterized in that, The nitrogen-containing antireflective film includes a SiON film.

4. A method for fabricating a semiconductor device, characterized in that, Includes the following steps: Coat the anti-reflective composite film as described in claim 2 or 3 onto the layer to be patterned; Photoresist is coated onto the antireflective composite film; The photomask is placed above the photoresist, and the photomask is irradiated using an exposure source; The layer to be patterned is then patterned.

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