Anti-reflective coating composition, preparation method and application thereof

Abstract

The present invention relates to the field of photolithography technology and provides an antireflective coating composition, its preparation method, and its application. The antireflective coating composition comprises 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 comprises p-toluenesulfonic acid and an organic acid A; the organic acid A has an ether bond in its molecular structure; and the organic acid A comprises one of ethoxyacetic acid, phenoxyacetic acid, and 2-naphthyloxyacetic acid. This technical solution solves the problem of poor thickness uniformity in BARC films in related technologies.

Description

Technical Field

[0001] The present invention relates to the field of photolithography technology, and in particular to an anti-reflective coating composition, a preparation method thereof, and an application thereof. Background Art

[0002] In the core photolithography process of semiconductor manufacturing, the bottom anti-reflective coating (BARC film) is made of an anti-reflective 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. The thickness uniformity of the BARC film, as a core parameter affecting the anti-reflective effect and patterning quality, is becoming a key technical bottleneck restricting the development of high-end photolithography processes.

[0003] During the photolithography process, the core function of the BARC film is to eliminate reflective interference from the silicon substrate surface by absorbing and scattering incident light, avoiding uneven photoresist exposure energy caused by the standing wave effect, and providing a smooth imaging base for the upper photoresist layer. However, in the actual film formation process, factors such as the anti-reflective coating's parallelization behavior, drying shrinkage characteristics, and interfacial interaction with the substrate can easily cause local deviations in film thickness. When this deviation exceeds the process tolerance, it not only causes reflectivity fluctuations that affect exposure uniformity, but may also cause critical dimension deviations or edge roughness problems through changes in photoresist film thickness, ultimately posing a significant threat to chip yield. Chinese patent CN112680052B, "An Anti-reflective Coating Composition and Its Application," discloses the use of an organic acid salt as a catalyst mixed with other components to prepare a BARC layer to address the problem of poor film thickness uniformity. However, the film thickness uniformity achieved is at most 0.5%, which is poor. Moreover, the test method, which measures the film thickness uniformity at 49 points, lacks accuracy.

[0004] In this technological development context, it is necessary to prepare an anti-reflective 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-reflective coating composition, a preparation method and an application thereof, which solve the problem in the related art that the thickness uniformity of a BARC film after the anti-reflective coating composition is formed into a film is poor.

[0006] The technical solutions of the present invention are as follows:

[0007] The present invention provides an anti-reflective coating composition, the raw materials of which include the following components in parts by weight: 14 to 20 parts of a matting resin, 1 to 4 parts of a catalyst, 2 to 8 parts of a cross-linking agent, and 400 to 1300 parts of a solvent;

[0008] The catalyst comprises p-toluenesulfonic acid and organic acid A;

[0009] The molecular structure of the organic acid A contains an ether bond;

[0010] The organic acid A includes one of ethoxyacetic acid, phenoxyacetic acid, and 2-naphthyloxyacetic acid.

[0011] As a further technical solution, the mass ratio of p-toluenesulfonic acid to organic acid A is 3-5:1.

[0012] As a further technical solution, the mass ratio of p-toluenesulfonic acid to organic acid A is 4:1.

[0013] In the present invention, the mass ratio of p-toluenesulfonic acid to 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.

[0014] In the present invention, when the catalyst in the raw materials of the anti-reflective coating composition is p-toluenesulfonic acid and organic acid A in a mass ratio of 3 to 5:1, the p-toluenesulfonic acid, as the primary catalyst, provides the main driving force for the cross-linking reaction, allowing the reaction to proceed within a reasonable time. The organic acid A then fine-tunes the reaction rate, preventing the cross-linking reaction from being too rapid due to the strong catalytic effect of p-toluenesulfonic acid. When the mass ratio of p-toluenesulfonic acid to organic acid A is 3 to 5:1, the organic acid A can appropriately suppress the reaction rate in the early stages of the cross-linking reaction, allowing the various components in the coating to have more time to diffuse and distribute evenly in the solvent. Therefore, this coordinated regulation of the cross-linking reaction rate ensures a relatively consistent degree of cross-linking in all regions of the coating during film formation, thereby effectively improving the thickness uniformity of the BARC film after the anti-reflective coating composition is formed.

[0015] As a further technical solution, the organic acid A is ethoxyacetic acid.

[0016] In the present invention, when organic acid A is ethoxyacetic acid, the thickness uniformity of the BARC film is further improved. Compared with phenoxyacetic acid and 2-naphthyloxyacetic acid, ethoxyacetic acid has less steric hindrance, is more flexible, and has better flexibility. Therefore, it is easier to play a role in synergistically regulating film thickness uniformity, further improving the thickness uniformity of the BARC film.

[0017] As a further technical solution, the cross-linking agent includes one or more of melamine formaldehyde resin, benzoguanamine formaldehyde resin, and glycoluril formaldehyde resin.

[0018] In the present invention, the melamine formaldehyde resin contains multiple active methylol functional groups in its molecular structure, which can undergo a 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, enabling the coating to resist external forces and chemical erosion.

[0019] 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, it 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-linked 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 impact on the optical properties of the coating, and helps to optimize the anti-reflection performance.

[0020] 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. At the same time, it can also adjust other properties of the coating, such as impact resistance, to a certain extent.

[0021] As a further technical solution, the solvent includes one or more of propylene glycol methyl ether acetate, cyclopentanone, and propylene glycol methyl ether.

[0022] In the present invention, the solvent in the anti-reflective coating composition can fully dissolve the other raw materials of the anti-reflective coating to form a uniform and stable solution. The molecular structure of propylene glycol methyl ether acetate comprises a propylene glycol segment, a methyl ether group, and an acetate group. This structure gives it excellent solubility and enables it to form intermolecular interactions with coating components such as matting resins, crosslinking agents, and catalysts, such as hydrogen bonds and van der Waals forces, thereby effectively dissolving and dispersing them in the system. The cyclopentanone molecule has a cyclic structure, a certain polarity, and a relatively high boiling point. Its polarity gives it excellent solubility for various organic compounds and can fully dissolve various components in the anti-reflective coating. The high boiling point means that its volatilization rate is relatively slow, providing more time for the crosslinking reaction of various components during the coating drying process, which is conducive to forming a dense and uniform coating structure. Propylene glycol methyl ether has excellent solubility for components such as resins and crosslinking agents in the coating, enabling them to be uniformly dispersed in the solution, thereby improving the leveling properties of the coating.

[0023] The present invention also provides a method for preparing an anti-reflective coating composition, which comprises the following steps:

[0024] The matting resin, catalyst and cross-linking agent are added into a solvent and mixed to obtain the anti-reflective coating composition.

[0025] As a further technical solution, during the mixing, the temperature is 80-100° C. and the time is 3-4 hours.

[0026] 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 a photolithography process.

[0027] The working principle and beneficial effects of the present invention are:

[0028] The present invention uses p-toluenesulfonic acid and an organic acid A containing an ether bond 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, by virtue of its acidity, rapidly reduces the activation energy of the reaction, thereby promoting a rapid cross-linking and curing reaction of components such as a matting resin and a cross-linking agent. At the same time, the organic acid A containing an ether bond in its molecular structure The molecules are given flexibility, so that they improve the leveling properties of the coating while having a catalytic effect. Due to their flexibility, they can be interspersed and arranged between macromolecules such as matte resins, effectively reducing the tendency of macromolecules to agglomerate, prompting the various components to be evenly dispersed in the solvent, so that the coating begins to be applied and solidified into a film and is tightly combined. In addition, while the organic acid A improves the leveling properties of the coating, it also makes the p-toluenesulfonic acid molecules more evenly dispersed, so that the originally relatively concentrated catalytic active sites of the p-toluenesulfonic acid can be more evenly dispersed in the coating system. Therefore, the composite catalyst system of the present invention significantly improves the film thickness uniformity of the BARC film through synergistic effect. DETAILED DESCRIPTION

[0029] 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 embodiments described 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 making any creative efforts are within the scope of protection of the present invention.

[0030] In the following examples and comparative examples, the model of the melamine formaldehyde resin is CYMEL 385, the model of the benzoguanamine formaldehyde resin is CYMEL 1123, and the model of the glycoluril formaldehyde resin is CYMEL 1172;

[0031] The matting resin is prepared from glycidyl methacrylate, hydroxypropyl methacrylate and 9-anthracenecarboxylic acid in a molar ratio of 1:1:1 according to a conventional method and has a weight-average molecular weight of 15,000.

[0032] Example 1

[0033] An anti-reflective coating composition, comprising the following components in parts by weight: 20 parts of a matting resin, 4 parts of a catalyst, 4 parts of a melamine formaldehyde resin, 4 parts of a benzoguanamine formaldehyde resin, 1000 parts of propylene glycol methyl ether acetate, and 300 parts of propylene glycol methyl ether;

[0034] The catalyst includes p-toluenesulfonic acid and phenoxyacetic acid in a mass ratio of 7:1;

[0035] The method for preparing an anti-reflective coating composition comprises the following steps:

[0036] The matting resin, catalyst, melamine formaldehyde resin and benzoguanamine formaldehyde resin were added to a mixed solvent of propylene glycol methyl ether acetate and propylene glycol methyl ether, and mixed at 100° C. for 3 hours to obtain an anti-reflective coating composition.

[0037] Example 2

[0038] An anti-reflective coating composition, comprising the following components in parts by weight: 14 parts of a matting resin, 1 part of a catalyst, 2 parts of a glycoluril formaldehyde resin, 150 parts of propylene glycol methyl ether acetate, and 250 parts of propylene glycol methyl ether;

[0039] The catalyst includes p-toluenesulfonic acid and 2-naphthyloxyacetic acid in a mass ratio of 2:1;

[0040] The method for preparing an anti-reflective coating composition comprises the following steps:

[0041] The matting resin, catalyst and glycoluril formaldehyde resin were added to a mixed solvent of propylene glycol methyl ether acetate and propylene glycol methyl ether, and mixed at 80° C. for 4 hours to obtain an anti-reflective coating composition.

[0042] Example 3

[0043] The only difference between this embodiment and embodiment 2 is that the mass ratio of p-toluenesulfonic acid to 2-naphthyloxyacetic acid in this embodiment is 6:1.

[0044] Example 4

[0045] The only difference between this embodiment and embodiment 2 is that the mass ratio of p-toluenesulfonic acid to 2-naphthyloxyacetic acid in this embodiment is 3:1.

[0046] Example 5

[0047] The only difference between this embodiment and embodiment 2 is that the mass ratio of p-toluenesulfonic acid to 2-naphthyloxyacetic acid in this embodiment is 4:1.

[0048] Example 6

[0049] The only difference between this embodiment and embodiment 2 is that the mass ratio of p-toluenesulfonic acid to 2-naphthyloxyacetic acid in this embodiment is 5:1.

[0050] Example 7

[0051] The only difference between this embodiment and embodiment 5 is that in this embodiment, 2-naphthyloxyacetic acid is replaced by ethoxyacetic acid of equal mass.

[0052] Comparative Example 1

[0053] The only difference between this comparative example and Example 2 is that the catalyst in this comparative example is p-toluenesulfonic acid.

[0054] Comparative Example 2

[0055] The only difference between this comparative example and Example 2 is that the catalyst in this comparative example is 2-naphthyloxyacetic acid.

[0056] Experimental example

[0057] The anti-reflective coating compositions prepared in Examples 1-7 and Comparative Examples 1-2 were spin-coated on a silicon wafer surface, and after cross-linking by baking at 200°C / 120 sec, the film thickness uniformity of the coating surface was measured at 100 points. The test results are shown in Table 1.

[0058] Film thickness uniformity = (maximum film thickness - minimum film thickness) / (maximum film thickness + minimum film thickness) × 100%.

[0059] Table 1 Film thickness uniformity test results

[0060]

[0061] As can be seen from Table 1, the thickness uniformity of the BARC layer prepared from the anti-reflective coating of the present invention reaches less than 0.38%. Therefore, the present invention uses p-toluenesulfonic acid and an organic acid containing an ether bond in its molecular structure to produce a synergistic effect, thereby improving the thickness uniformity of the BARC layer after the anti-reflective coating composition is formed.

[0062] The above are only 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 principles of the present invention should be included in the scope of protection 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 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.

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

5. The 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. The 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, catalyst and cross-linking agent are added into a solvent and mixed to obtain the anti-reflective coating composition.

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

9. Use of the anti-reflective coating composition according to any one of claims 1 to 6 or the 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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