JP-7854980-B2 - Photocurable composition, pattern forming method, and cured film

Inventors

• 昆野 健理
• 森 莉紗子

Assignees

• 東京応化工業株式会社

Dates

Publication Date

20260507

Application Date

20220307

Priority Date

20210316

Claims (6)

1. Metal oxide nanoparticles (X) and Photopolymerizable sulfur compounds (C) and It contains, The aforementioned metal oxide nanoparticles (X) are titania ( TiO₂ ) nanoparticles. The aforementioned photopolymerizable sulfur compound (C) is a compound represented by the following general formula (c-1), The total content of the metal oxide nanoparticles (X) and the photopolymerizable sulfur compound (C) is 100 parts by mass, and the content of the photopolymerizable sulfur compound (C) is 10 to 40 parts by mass. A photocurable composition for photoimprint lithography that does not contain a photopolymerizable monomer having a polymerizable functional group other than the aforementioned photopolymerizable sulfur compound (C) . [In the formula, R 11 to R 14 and R 21 to R 24 each independently represent a hydrogen atom, an alkyl group, or a halogen atom, and R 5 represents a polymerizable functional group.]
2. The photocurable composition for photoimprint lithography according to claim 1, wherein the volume-average primary particle diameter of the metal oxide nanoparticles (X) is 100 nm or less.
3. The photocurable composition for photoimprint lithography according to claim 1 or 2, wherein the content of the photopolymerizable sulfur compound (C) is 20 to 40 parts by mass per 100 parts by mass of the total content of the metal oxide nanoparticles (X) and the photopolymerizable sulfur compound (C).
4. A photocurable composition for photoimprint lithography according to any one of claims 1 to 3, wherein the resin cured film formed using the aforementioned photocurable composition for photoimprint lithography has a refractive index of 1.86 or higher at a wavelength of 530 nm.
5. A step of forming a photocurable film on a substrate using a photocurable composition for photoimprint lithography described in any one of claims 1 to 4 , A step of pressing a mold having an uneven pattern onto the photocurable film to transfer the uneven pattern onto the photocurable film, The process of pressing the mold onto the photocurable film and exposing the photocurable film on which the uneven pattern has been transferred to it to form a cured film, A step of peeling the mold from the cured film, A pattern forming method having the following characteristics.
6. A cured film obtained by curing a photocurable composition for photoimprint lithography according to any one of claims 1 to 4.

Description

The present invention relates to a photocurable composition and a pattern forming method. This application claims priority based on Japanese Patent Application No. 2021-042612, filed in Japan on March 16, 2021, and the contents of that application are incorporated herein by reference. Lithography is a core technology in the manufacturing process of semiconductor devices, and with the increasing integration of semiconductor integrated circuits (ICs) in recent years, further miniaturization of wiring is progressing. Common miniaturization methods include shortening the wavelength of light sources by using shorter wavelength light sources such as KrF excimer lasers, ArF excimer lasers, F2 lasers, EUV (extreme ultraviolet light), EB (electron beam), and X-rays, as well as increasing the numerical aperture (NA) of the lenses of the exposure equipment (high NA). In this context, nanoimprint lithography, a method for forming fine patterns in semiconductors, is expected to be promising in terms of productivity and other factors. This method involves pressing a mold with a predetermined pattern onto a curable film formed on a substrate to transfer the pattern of the mold to the curable film. Nanoimprint lithography uses photocurable compositions containing photocurable compounds that harden with light (ultraviolet light, electron beam). In this case, a mold having a predetermined pattern is pressed onto a curable film containing the photocurable compound, then light is irradiated to harden the photocurable compound, and then the mold is peeled off from the hardened film to obtain a transfer pattern (structure). Photocurable compositions used in nanoimprint lithography require specific properties, including ease of application to substrates by methods such as spin coating, and curability upon heating or exposure. Poor application to the substrate can lead to variations in the film thickness of the photocurable composition, resulting in reduced pattern transfer when a mold is pressed onto the curable film. Curability is also a crucial property for maintaining the desired dimensions of the pattern formed by mold pressing. In addition, photocurable compositions are required to have good mold release properties when peeling the mold from the cured film. In recent years, nanoimprint lithography has been explored for improving the functionality of 3D sensors for autonomous driving and AR (augmented reality) waveguides in AR glasses. For 3D sensors and AR glasses, there is a need for higher refractive index materials in the permanent film materials that constitute part of the device. One known method for increasing the refractive index of nanoimprint materials is to add metal oxide nanoparticles. For example, Patent Document 1 describes a photocurable resin composition in which the refractive index is increased by incorporating metal oxide nanoparticles such as titanium oxide or zirconium oxide. Furthermore, as a means of increasing the refractive index of nanoimprint materials, for example, Patent Document 2 describes a photocurable resin composition in which the refractive index is increased by using a compound having a biphenyl skeleton and polymerizable groups, and a photopolymerization initiator. Japanese Patent Publication No. 2013-191800Japanese Patent Publication No. 2013-95833 This is a schematic process diagram illustrating one embodiment of a nanoimprint pattern formation method.This is a schematic process diagram illustrating an example of an optional process. In this specification and in the claims, "aliphatic" is defined as a concept relative to aromatic, meaning a group, compound, etc., that does not possess aromaticity. Unless otherwise specified, "alkyl group" includes linear, branched, and cyclic monovalent saturated hydrocarbon groups. The same applies to alkyl groups within alkoxy groups. "(Meth)acrylate" means at least one of acrylate and methacrylate. When it is stated that a group "may have substituents," this includes both cases where a hydrogen atom (-H) is substituted with a monovalent group and cases where a methylene group ( -CH2- ) is substituted with a divalent group. "Exposure" is a concept that includes all forms of radiation exposure. (Photocurable composition) A photocurable composition according to a first aspect of the present invention contains metal oxide nanoparticles (X) and a photopolymerizable sulfur compound (C). <(X) component> Component (X) is a metal oxide nanoparticle. "Nanoparticles" refer to particles with a volume-average primary particle diameter on the order of nanometers (less than 1000 nm). Metal oxide nanoparticles are metal oxide particles with an average primary particle diameter on the order of nanometers. The volume-average primary particle diameter of component (X) is preferably 100 nm or less. The volume-average primary particle diameter of component (X) is preferably 0.1 to 100 nm, more preferably 1 to 60 nm, even more preferably 1 to 50 nm, even more preferably