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JP-7854981-B2 - Photocurable composition, pattern forming method, and cured film

JP7854981B2JP 7854981 B2JP7854981 B2JP 7854981B2JP-7854981-B2

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
20220311
Priority Date
20210316

Claims (7)

  1. Metal oxide nanoparticles (X) and Photopolymerizable compound (B), It contains a photoradical polymerization initiator (C) and The content of the photoradical polymerization initiator (C) is 10 parts by mass or more with respect to 100 parts by mass of the total content of the metal oxide nanoparticles (X) and the photopolymerizable compound (B), The metal oxide nanoparticles (X) include at least one selected from the group consisting of titania nanoparticles and zirconia nanoparticles. A photocurable composition for photoimprint lithography on which a mold pattern is transferred.
  2. The photocurable composition 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 according to claim 1 or 2, wherein, per 100 parts by mass of the total content of the metal oxide nanoparticles (X) and the photopolymerizable compound (B), the content of the metal oxide nanoparticles (X) is 60 to 90 parts by mass, and the content of the photopolymerizable compound (B) is 10 to 40 parts by mass.
  4. The photocurable composition according to any one of claims 1 to 3, wherein the cured film formed using the photocurable composition has a refractive index of 1.70 or higher at a wavelength of 530 nm.
  5. The photocurable composition according to any one of claims 1 to 4, wherein the haze value of a cured film with a thickness of 600 nm formed using the photocurable composition is 0.4% or less, as measured according to ASTM D100.
  6. A step of forming a photocurable film on a substrate using the photocurable composition described in any one of claims 1 to 5, 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 involves pressing the mold onto the photocurable film while exposing the photocurable film on which the uneven pattern has been transferred to the mold to form a cured film, A step of peeling the mold from the cured film, A pattern forming method having the following characteristics.
  7. A cured film obtained by curing a photocurable composition according to any one of claims 1 to 5.

Description

The present invention relates to a photocurable composition and a pattern forming method. This application claims priority based on Japanese Patent Application No. 2021-042611, 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 considered for improving the functionality of 3D sensors for autonomous driving and AR (augmented reality) waveguides in AR glasses. For 3D sensors and AR glasses, a high refractive index is required for the permanent film material that constitutes part of the device. One known method for increasing the refractive index of nanoimprint materials is the addition of metal oxide nanoparticles. For example, Patent Document 1 describes a photocurable resin composition in which a high refractive index is achieved by incorporating metal oxide nanoparticles such as titanium oxide or zirconium oxide. Patent No. 5952040 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) (hereinafter also referred to as "component (X)"), a photopolymerizable compound (B) (hereinafter also referred to as "component (B)"), and a photoradical polymerization initiator (C) (hereinafter also referred to as "component (C)"), wherein the content of component (C) is 10 parts by mass or more per 100 parts by mass of the total content of component (X) and component (B). <(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 a volume-average primary particle diameter on the order of nanometers. The 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 1 to 45 nm, and particularly preferably 1 to 40 nm.