Anti-reflection coating composition as well as preparation method and application thereof

Abstract

The invention relates to the technical field of photoetching, and provides an anti-reflection coating composition as well as a preparation method and application thereof. The anti-reflection coating composition comprises the following raw material components in parts by weight: 14-20 parts of extinction resin, 1-4 parts of a catalyst, 2-8 parts of a cross-linking agent and 400-1300 parts of a solvent, the catalyst comprises p-toluenesulfonic acid and organic acid A; the molecular structure of the organic acid A contains an ether bond; the organic acid A comprises one of ethoxyacetic acid, phenoxyacetic acid and 2-naphthoxyacetic acid. According to the technical scheme, the problem of poor film thickness uniformity of the BARC film in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the field of lithography technology. Specifically, it relates to an anti-reflection coating composition, a preparation method thereof, and an application thereof. Background Art

[0002] In the core lithography process of semiconductor manufacturing, the bottom anti-reflection coating (BARC film) is made of an anti-reflection coating composition. As a key functional layer connecting the silicon substrate and the photoresist, its performance directly determines the accuracy and reliability of nanoscale pattern transfer. And the film thickness uniformity of the BARC film, as a core parameter affecting the anti-reflection effect and patterning quality, is becoming a key technical bottleneck restricting the development of high-end lithography technology.

[0003] During the lithography process, the core function of the BARC film is to eliminate the reflection interference on the surface of the silicon substrate by absorbing and scattering incident light, avoid the uneven exposure energy of the photoresist caused by the standing wave effect, and at the same time provide a flat imaging substrate for the upper photoresist. However, in the actual film-forming process, factors such as the leveling behavior of the anti-reflection coating, the drying shrinkage characteristics, and the interfacial interaction with the substrate are very likely to cause local deviations in the film thickness. When this deviation exceeds the process tolerance, it will not only cause fluctuations in reflectivity and affect exposure uniformity, but may also cause critical dimension deviations or edge roughness problems through changes in the photoresist film thickness, ultimately posing a significant threat to the chip yield. Chinese Patent CN112680052B, "An Anti-Reflection Coating Composition and Its Application", discloses the use of organic acid salts as catalysts and mixing them with other components to prepare a BARC layer to solve the problem of poor film thickness uniformity. However, its film thickness uniformity reaches at most 0.5%, the film thickness uniformity is poor, and the test method is to measure the film thickness uniformity at 49 points, and the accuracy of the test method is insufficient.

[0004] Under such a technical development background, it is necessary to prepare an anti-reflection coating composition so that the BARC film obtained after film formation has excellent film thickness uniformity. Summary of the Invention

[0005] The present invention provides an anti-reflection coating composition, a preparation method thereof, and an application thereof, which solves the problem of poor film thickness uniformity of the BARC film after film formation of the anti-reflection coating composition in the related art.

[0006] The technical solution of the present invention is as follows: The present invention provides an anti-reflection coating composition, the raw materials of which include the following components in parts by weight: 14 - 20 parts of a matting resin, 1 - 4 parts of a catalyst, 2 - 8 parts of a crosslinking agent, and 400 - 1300 parts of a solvent; The catalyst includes p-toluenesulfonic acid and organic acid A; The molecular structure of the organic acid A contains an ether bond; The organic acid A includes one of ethoxyacetic acid, phenoxyacetic acid, and 2-naphthyloxyacetic acid.

[0007] As a further technical solution, the mass ratio of the p-toluenesulfonic acid to the organic acid A is 3-5:1.

[0008] As a further technical solution, the mass ratio of the p-toluenesulfonic acid to the organic acid A is 4:1.

[0009] In the present invention, the mass ratio of the p-toluenesulfonic acid to the organic acid A can be 3:1, 3.1:1, 3.2:1, 3.3:1, 3.4:1, 3.5:1, 3.6:1, 3.7:1, 3.8:1, 3.9:1, 4:1, 4.1:1, 4.2:1, 4.3:1, 4.4:1, 4.5:1, 4.6:1, 4.7:1, 4.8:1, 4.9:1, 5:1, and is preferably 4:1.

[0010] In the present invention, in the raw materials of the antireflection coating composition, when the catalyst is p-toluenesulfonic acid and organic acid A with a mass ratio of 3-5:1, the p-toluenesulfonic acid serves as the main catalyst, providing the main driving force required for the crosslinking reaction and enabling the reaction to proceed within a reasonable time. The organic acid A plays a role in finely adjusting the reaction rate, preventing the crosslinking reaction from being too rapid due to the strong catalytic effect of the p-toluenesulfonic acid. When the mass ratio of the p-toluenesulfonic acid to the organic acid A is 3-5:1, the organic acid A can appropriately inhibit the reaction rate at the initial stage of the crosslinking reaction, allowing each component in the coating to have more sufficient time to uniformly diffuse and distribute in the solvent. Therefore, this synergistically regulated crosslinking reaction rate ensures that the crosslinking degree in each region is relatively consistent during the film-forming process of the coating, thereby effectively improving the film thickness uniformity of the BARC film after the antireflection coating composition forms a film.

[0011] As a further technical solution, the organic acid A is ethoxyacetic acid.

[0012] In the present invention, when the organic acid A is ethoxyacetic acid, the film thickness uniformity of the BARC film is further improved. Ethoxyacetic acid has a smaller steric hindrance, greater flexibility, and better flexibility compared to phenoxyacetic acid and 2-naphthyloxyacetic acid. Therefore, it is more likely to play a role in synergistically regulating the film thickness uniformity, further improving the film thickness uniformity of the BARC film.

[0013] As a further technical solution, the crosslinking agent includes one or more of melamine formaldehyde resin, benzoguanamine formaldehyde resin, and glycoluril formaldehyde resin.

[0014] In the present invention, the melamine formaldehyde resin molecular structure contains multiple active methylol functional groups, which can undergo condensation reaction with the active groups on the matting resin molecules, thereby connecting the matting resin molecules together and gradually building a three-dimensional cross-linked network structure, thereby enhancing the cohesion and stability of the anti-reflective coating composition coating, so that the coating can resist external forces and chemical erosion.

[0015] In the present invention, the benzoguanamine formaldehyde resin contains active functional groups that can participate in the cross-linking reaction. Under the action of a catalyst, the benzoguanamine formaldehyde resin is cross-linked with the matting resin. The presence of the benzene ring increases the rigidity and steric hindrance of the molecule, making the structure of the cross-linking network more compact and regular, which not only ensures the hardness and heat resistance of the coating, but also affects the propagation of light in the coating, has a certain influence on the optical properties of the coating, and helps to optimize the anti-reflection performance.

[0016] In the present invention, the active groups in the glycoluril formaldehyde resin molecules undergo a cross-linking reaction with the matting resin under the action of a catalyst, and the formed cross-linked network has different densities and flexibility. The specific structure in the glycoluril formaldehyde resin may make the cross-linked network have a certain elasticity, giving the coating better flexibility, which has advantages in some application scenarios that require the coating to adapt to certain deformations, and can also adjust other properties of the coating to a certain extent, such as impact resistance.

[0017] As a further technical solution, the solvent includes one or more of propylene glycol methyl ether acetate, cyclopentanone, and propylene glycol methyl ether.

[0018] In the present invention, the solvent in the anti-reflective coating composition can fully dissolve other raw materials of the anti-reflective coating to form a uniform and stable solution, wherein the molecular structure of propylene glycol methyl ether acetate comprises a propylene glycol segment, a methyl ether group and an acetate group, and this structure enables it to have good dissolving ability, and can form intermolecular interactions with coating components such as matting resin, crosslinking agent and catalyst, such as hydrogen bonds, van der Waals forces, etc., so as to effectively dissolve and disperse them in the system; the cyclopentanone molecule is a ring structure, has a certain polarity and a relatively high boiling point, and its polarity enables it to have good solubility for a variety of organic compounds, and can fully dissolve various components in the anti-reflective coating, and the high boiling point means that its volatilization speed is relatively slow, and in the drying process of the coating, it provides a relatively ample time for the crosslinking reaction of each component, which is conducive to forming a dense and uniform coating structure; propylene glycol methyl ether has a good dissolving ability for components such as resins and crosslinking agents in the coating, and can evenly disperse them in the solution, so as to make the leveling property of the coating better.

[0019] The present invention also provides a method for preparing an anti-reflective coating composition, which is used to prepare the anti-reflective coating composition, comprising the following steps: The matting resin, the catalyst and the cross-linking agent are added into the solvent and mixed to obtain the anti-reflective coating composition.

[0020] As a further technical solution, during the mixing, the temperature is 80-100° C. and the time is 3-4 hours.

[0021] The present invention also proposes the use of the anti-reflective coating composition or the anti-reflective coating composition prepared by the preparation method of the anti-reflective coating composition in photolithography.

[0022] The working principle and beneficial effects of the present invention are: The present invention adopts p-toluenesulfonic acid and an organic acid A containing ether bonds in its molecular structure to form a composite catalyst as a raw material for an anti-reflective coating composition, thereby improving the uniformity of the thickness of a BARC film formed by the anti-reflective coating composition. Different from the prior art in which p-toluenesulfonic acid and other organic acids are commonly used in anti-reflective coating compositions to play a catalytic role in cross-linking and curing, the present invention also focuses on using a catalyst to improve the uniformity of the thickness of a BARC film formed by the anti-reflective coating composition. In the present invention, p-toluenesulfonic acid rapidly reduces the reaction activation energy by virtue of its acidity, and promotes rapid cross-linking and curing reactions of components such as matting resins and cross-linking agents. At the same time, the organic acid A containing ether bonds in its molecular structure The molecules are endowed with flexibility, so that they have a catalytic effect and improve the leveling property of the coating at the same time. Due to their flexibility, they can be interspersed and arranged between macromolecules such as matte resins, effectively reducing the tendency of macromolecules to agglomerate, and promoting the uniform dispersion of various components in the solvent, so that the coating begins to be coated and solidified into a film and tightly combined. In addition, while the organic acid A improves the leveling property of the coating, it also makes the p-toluenesulfonic acid molecules more evenly dispersed, so that the originally relatively concentrated catalytic active sites of p-toluenesulfonic acid can be more evenly dispersed in the coating system. Therefore, the composite catalyst system of the present invention significantly improves the uniformity of the film thickness of the BARC film through synergistic effect. DETAILED DESCRIPTION

[0023] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] In the following examples and comparative examples, the model of melamine formaldehyde resin is CYMEL 385, the model of benzoguanamine formaldehyde resin is CYMEL 1123, and the model of glycoluril formaldehyde resin is CYMEL 1172; The matting resin is a matting resin with a weight-average molecular weight of 15,000, which is prepared by glycidyl methacrylate, hydroxypropyl methacrylate, and 9-anthracene carboxylic acid in a molar ratio of 1:1:1 according to a conventional method.

[0025] Example 1 An antireflection coating composition, the raw materials of which include the following components in parts by weight: 20 parts of matting resin, 4 parts of catalyst, 4 parts of melamine formaldehyde resin, 4 parts of phenylmelamine formaldehyde resin, 1000 parts of propylene glycol monomethyl ether acetate, and 300 parts of propylene glycol monomethyl ether; The catalyst includes p-toluenesulfonic acid and phenoxyacetic acid in a mass ratio of 7:1; A preparation method of the antireflection coating composition, which includes the following steps: Adding the matting resin, catalyst, melamine formaldehyde resin, and phenylmelamine formaldehyde resin into a mixed solvent of propylene glycol monomethyl ether acetate and propylene glycol monomethyl ether, and mixing at 100 °C for 3 h to obtain the antireflection coating composition.

[0026] Example 2 An antireflection coating composition, the raw materials of which include the following components in parts by weight: 14 parts of matting resin, 1 part of catalyst, 2 parts of glycoluril formaldehyde resin, 150 parts of propylene glycol monomethyl ether acetate, and 250 parts of propylene glycol monomethyl ether; The catalyst includes p-toluenesulfonic acid and 2-naphthoxyacetic acid in a mass ratio of 2:1; A preparation method of the antireflection coating composition, which includes the following steps: Adding the matting resin, catalyst, and glycoluril formaldehyde resin into a mixed solvent of propylene glycol monomethyl ether acetate and propylene glycol monomethyl ether, and mixing at 80 °C for 4 h to obtain the antireflection coating composition.

[0027] Example 3 The difference between this example and Example 2 is only that the mass ratio of p-toluenesulfonic acid and 2-naphthoxyacetic acid in this example is 6:1.

[0028] Example 4 The difference between this example and Example 2 is only that the mass ratio of p-toluenesulfonic acid and 2-naphthoxyacetic acid in this example is 3:1.

[0029] Example 5 The difference between this example and Example 2 is only that the mass ratio of p-toluenesulfonic acid and 2-naphthoxyacetic acid in this example is 4:1.

[0030] Example 6 The difference between this example and Example 2 is only that the mass ratio of p-toluenesulfonic acid and 2-naphthoxyacetic acid in this example is 5:1.

[0031] Example 7 The difference between this embodiment and Embodiment 5 is only that in this embodiment, 2-naphthoxyacetic acid is replaced with ethoxyacetic acid of equal mass.

[0032] Comparative Example 1 The difference between this comparative example and Embodiment 2 is only that the catalyst in this comparative example is p-toluenesulfonic acid.

[0033] Comparative Example 2 The difference between this comparative example and Embodiment 2 is only that the catalyst in this comparative example is 2-naphthoxyacetic acid.

[0034] Experimental Example The antireflection coating compositions prepared in Examples 1-7 and Comparative Examples 1-2 were spin-coated on the surface of a silicon wafer. After baking and cross-linking at 200 °C for 120 seconds, 100 points were taken to measure the film thickness uniformity of the coating surface. The test results are shown in Table 1; Film thickness uniformity = (maximum film thickness - minimum film thickness) / (maximum film thickness + minimum film thickness) × 100%.

[0035] Table 1 Test Results of Film Thickness Uniformity

[0036] As can be seen from Table 1, the film thickness uniformity of the BARC layer prepared from the antireflection coating in the present invention reaches below 0.38%. Therefore, in the present invention, the compounding of p-toluenesulfonic acid and an organic acid containing an ether bond in the molecular structure produces a synergistic effect, improving the film thickness uniformity of the BARC layer after the antireflection coating composition forms a film.

[0037] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An anti-reflective coating composition, characterized in that: The raw materials include the following components in parts by weight: 14-20 parts of matting resin, 1-4 parts of catalyst, 2-8 parts of cross-linking agent, and 400-1300 parts of solvent; The catalyst comprises p-toluenesulfonic acid and organic acid A; The organic acid A contains an ether bond in its molecular structure; The organic acid A includes one of ethoxyacetic acid, phenoxyacetic acid and 2-naphthoxyacetic acid.

2. An anti-reflective coating composition according to any one of claim 1, characterized in that: The mass ratio of the p-toluenesulfonic acid to the organic acid A is 3-5:

1.

3. An anti-reflective coating composition according to claim 2, characterized in that: The mass ratio of the p-toluenesulfonic acid to the organic acid A is 4:

1.

4. An anti-reflective coating composition according to claim 1, characterized in that: The organic acid A is ethoxyacetic acid.

5. An anti-reflective coating composition according to claim 1, characterized in that: The cross-linking agent includes one or more of melamine formaldehyde resin, benzoguanamine formaldehyde resin and glycoluril formaldehyde resin.

6. An anti-reflective coating composition according to claim 1, characterized in that: The solvent includes one or more of propylene glycol methyl ether acetate, cyclopentanone, and propylene glycol methyl ether.

7. A method for preparing an anti-reflective coating composition, for preparing an anti-reflective coating composition according to any one of claims 1 to 6, characterized in that: The following steps are involved: The matting resin, the catalyst and the cross-linking agent are added into the solvent and mixed to obtain the anti-reflective coating composition.

8. The method for preparing an anti-reflective coating composition according to claim 7, characterized in that: During the mixing, the temperature is 80-100° C. and the time is 3-4 hours.

9. Use of an anti-reflective coating composition according to any one of claims 1 to 6 or an anti-reflective coating composition prepared by the preparation method according to any one of claims 7 to 8 in a photolithography process.

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