Photocurable composition

Abstract

The photocurable composition can contain a polymerizable material and at least one photoinitiator. The polymerizable material contains at least one polyfunctional vinylbenzene monomer in an amount of at least 30% by weight based on the total weight of the polymerizable material. The at least one photoinitiator contains an oxime ester compound. The photocurable composition can be adapted such that the UV shrinkage rate after forming a photocured layer at 23°C is 4.0% or less, and the thermal shrinkage after baking treatment of the photocured layer at 350°C is 3.5% or less.

Description

Technical Field

[0001] The present disclosure relates to a photocurable composition, and more particularly to a photocurable composition suitable for inkjet adaptable planarization.

Background Art

[0002] Inkjet adaptable planarization (IAP) is a process for planarizing the surface of a substrate (e.g., a wafer including an electronic circuit) by ejecting droplets of a curable composition onto the surface of the substrate and bringing a flat superstrate into direct contact with the applied liquid to form a flat liquid layer. The flat liquid layer is typically solidified under exposure to UV light, and after removal of the superstrate, a flat surface is obtained that is subjected to subsequent processing steps such as baking, etching, and / or further deposition steps. There is a need for improved IAP materials that provide a planar cured layer with high thermal stability.

Summary of the Invention

[0003] In one embodiment, the photocurable composition can include a polymerizable material and at least one photoinitiator, the polymerizable material includes at least one polyfunctional vinylbenzene monomer in an amount of at least 30% by weight based on the total weight of the polymerizable material, the at least one photoinitiator includes an oxime ester compound, and the photocurable composition is adapted such that the UV shrinkage rate after forming a photocured layer at 23°C is 4.0% or less.

[0004] In other embodiments, the photocurable composition is adapted such that the photocured layer formed from the photocurable composition can have a thermal shrinkage rate of 3.5% or less after a baking treatment at 350°C, and the baking treatment includes baking the photocured layer for 2 minutes in a nitrogen 2 atmosphere on a stainless steel plate having a temperature of 350°C.

[0005] In one aspect, the oxime ester compound can have the structure of formula (1), JPEG2025516450000001.jpg22170R 1 is an aromatic ring system or a heteroaromatic ring system, and R 2 is H or C 1 -C 8 alkyl, and R 3 is H or C 1 -C 8 alkyl.

[0006] In certain embodiments, the oxime ester compound can include the structure of formula (2). JPEG2025516450000002.jpg32170

[0007] In other embodiments, the oxime ester compound can include the structure of formula (3). JPEG2025516450000003.jpg50170

[0008] In one embodiment, the photocurable composition can further include at least 0.05 wt% of 4-tert-butylcatechol (TBC).

[0009] In other embodiments of the photocurable composition, the amount of the oxime ester compound can be at least 1 wt% and at most 7 wt% based on the total weight of the photocurable composition.

[0010] In certain embodiments, the at least one photoinitiator can further include a photoinitiator that is not an oxime ester compound.

[0011] In other embodiments of the photocurable composition, the amount of the polymerizable material can be at least 85 wt% based on the total weight of the photocurable composition.

[0012] In one embodiment, the polyfunctional vinylbenzene monomer can include at least 3 vinyl groups. In certain embodiments, the polyfunctional vinylbenzene monomer can be a biphenyl compound containing 3 vinyl groups.

[0013] In another embodiment of the photocurable composition, the polymerizable material can further include at least one polyfunctional acrylate monomer. In certain embodiments, the polyfunctional acrylate monomer can include at least one acrylate group and at least one vinyl group.

[0014] In still another aspect of the photocurable composition, the total amount of the polyfunctional vinylbenzene monomer and the polyfunctional acrylate monomer can be at least 85% by weight based on the total weight of the polymerizable material.

[0015] In a further aspect, the polymerizable material of the photocurable composition can have a weight % ratio of the polyfunctional acrylate monomer to the polyfunctional vinylbenzene monomer in the range of 2:1 to 1:2.

[0016] In a further aspect, the viscosity of the photocurable composition can be 50 mPa·s or less.

[0017] In one embodiment, a method of forming a photocured layer on a substrate includes applying a layer of a photocurable composition on the substrate, the photocurable composition including a polymerizable material and at least one photoinitiator, the polymerizable material including at least one polyfunctional vinylbenzene monomer in an amount of at least 30% by weight based on the total weight of the polymerizable material, the at least one photoinitiator including an oxime ester compound; contacting the photocurable composition with a template or a superstrate; irradiating the photocurable composition with light to form a photocured layer; and removing the template or the superstrate from the photocured layer.

[0018] In one aspect of the method, the step of irradiating the photocurable composition can be performed with UV light, and the UV shrinkage rate after forming the photocured layer can be 4.0% or less.

[0019] In another aspect of the method, the photocurable layer can have a heat shrinkage rate of 3.5% or less after baking at 350 °C, and the baking treatment is carried out on a stainless steel plate having a temperature of 350 °C in an N 2 atmosphere and includes baking the photocurable layer for 2 minutes.

[0020] In other embodiments, a method for manufacturing an article includes a step of applying a layer of a photocurable composition onto a substrate, wherein the photocurable composition includes a polymerizable material and at least one photoinitiator, the polymerizable material includes at least one polyfunctional vinylbenzene monomer in an amount of at least 30% by weight based on the total weight of the polymerizable material, and the at least one photoinitiator includes an oxime ester compound; a step of bringing the photocurable composition into contact with a template or a superstrate; a step of irradiating the photocurable composition with light to form a photocured layer; a step of removing the template or the superstrate from the photocured layer; a step of forming a pattern on the substrate; a step of processing the substrate on which the pattern is formed in the forming step; and a step of manufacturing an article from the substrate processed in the processing step.

Embodiments for Carrying Out the Invention

[0021] The following description is provided to assist in understanding the teachings disclosed herein and focuses on specific implementations and embodiments of the teachings. This focus is provided to assist in explaining the teachings and should not be construed as a limitation on the scope or applicability of the teachings.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The materials, methods, and examples are illustrative only and not intended to be limiting. Many details regarding specific materials and processing acts are conventional and can be found in textbooks and other sources of information within the imprinting and lithography arts outside the scope described herein.

[0023] As used herein, the terms "comprises", "comprising", "includes", "including", "has", "having", or any other variation thereof are intended to cover non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of features is not necessarily limited to only those features, and may include other features not expressly listed or inherent to such process, method, article, or apparatus.

[0024] As used herein, unless expressly stated to the contrary, "or" refers to an inclusive - or and not an exclusive - or. For example, condition A or B is satisfied if either A is true (or present) and B is false (or absent), A is false (or absent) and B is true (or present), or both A and B are true (or present).

[0025] Also, the use of "a" or "an" is employed to describe elements and components described herein. This is merely for convenience and to give a general sense of the scope of the invention. This specification should be read to include one or at least one, and the singular form includes the plural form unless it is obvious that it has a different meaning.

[0026] The present disclosure is directed to a photocurable composition comprising a polymerizable material and a photoinitiator, the photoinitiator can comprise an oxime ester compound, and the polymerizable material can comprise a polyfunctional vinylbenzene monomer in an amount of at least 30% by weight.

[0027] The photocurable composition of the present disclosure can have the advantage of being usable for inkjet adaptable planarization (IAP) treatment by having low viscosity, low shrinkage during curing, and very high thermal stability.

[0028] In one embodiment, the photocurable composition of the present disclosure can be adapted such that the UV shrinkage after forming a photocured layer at 23°C can be 4.0% or less, or 3.5% or less, or 3.0% or less.

[0029] In another embodiment, the photocured layer formed from the photocurable composition can have a shrinkage rate of 3.5% or less after a baking treatment at 350°C, and the baking treatment includes baking the photocured layer on a stainless steel plate having a temperature of 350°C for 2 minutes. In a further aspect, the linear shrinkage rate after the baking treatment at 350°C can be 3.0% or less, 2.5% or less, 2.0% or less, 1.5% or less, or 1.0% or less, or 0.5% or less.

[0030] In one embodiment, the oxime ester compound of the photoinitiator can have the structure of formula (1). JPEG2025516450000004.jpg22170R 1 is an aromatic ring system or a heteroaromatic ring system, and R 2 is H or C 1 -C 8 alkyl, and R 3 is H or C 1 -C 8 alkyl.

[0031] In a specific embodiment, the oxime ester compound may have the configuration of formula (2). JPEG2025516450000005.jpg32170

[0032] In another specific embodiment, the oxime ester compound may have the configuration of formula (3). JPEG2025516450000006.jpg50170

[0033] In a more specific embodiment, the oxime ester can have the structure of formula (4). JPEG2025516450000007.jpg42170

[0034] The amount of the oxime ester compound of the photoinitiator can be at least 1.0 wt%, or at least 1.5 wt%, or at least 2.0 wt%, or at least 2.5 wt%, or at least 3.0 wt%, or at least 3.5 wt%, or at least 4.0 wt% based on the total weight of the photocurable composition. In another embodiment, the amount of the oxime ester compound can be 10 wt% or less, or 8 wt% or less, or 7 wt% or less, or 6 wt% or less, or 5 wt% or less, or 4 wt% or less based on the total weight of the photocurable composition. The amount of the oxime ester compound of the photoinitiator can be a value between any of the above minimum and maximum numbers.

[0035] In one embodiment, the photoinitiator of the photocurable composition can further comprise at least one photoinitiator that is not an oxime ester compound.

[0036] The polymerizable material of the photocurable composition can be the main amount of the composition. In one embodiment, the amount of the polymerizable material can be at least 60 wt%, or at least 70 wt%, or at least 80 wt%, or at least 90 wt%, or at least 92 wt%, or at least 95 wt% based on the total weight of the photocurable composition.

[0037] As used herein, the term polyfunctional vinylbenzene of a polymerizable material relates to a polymerizable monomer containing one or more benzene rings and at least two vinyl groups directly bonded to the one or more benzene rings. In certain embodiments, the polyfunctional vinylbenzene can include at least three vinyl groups or at least four vinyl groups. In one embodiment, the polyfunctional vinylbenzene monomer can include two benzene rings and three vinyl groups bonded to the benzene rings. A non-limiting example of such a monomer can be 3,4’,5-trivinyl-1,1’ biphenyl (3VPH).

[0038] In one embodiment, the amount of the polyfunctional vinylbenzene monomer can be at least 30 wt%, such as at least 35 wt%, at least 40 wt%, at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 90 wt%, or at least 95 wt% based on the total weight of the polymerizable material. In another embodiment, the amount of the polyfunctional vinylbenzene monomer can be 98 wt% or less, or 95 wt% or less, or 90 wt% or less, or 80 wt% or less, or 70 wt% or less, or 60 wt% or less, or 50 wt% or less based on the total weight of the polymerizable material. The amount of the polyfunctional vinylbenzene monomer can be a value between any of the above minimum and maximum numbers.

[0039] In another embodiment, the polymerizable material can further include a polyfunctional acrylate monomer. In one embodiment, the polyfunctional acrylate monomer can include at least two acrylate groups, or at least three acrylate groups, or at least four acrylate groups. In another embodiment, the polyfunctional acrylate monomer can include at least one acrylate group and at least one vinyl group. As used herein, the term acrylic acid monomer relates to substituted and unsubstituted acrylic acid monomers. Non-limiting examples of substituted acrylate monomers are C 1 -C 8It can be an alkyl acrylate, such as methacrylate or ethyl acrylate. Further, as used herein, the term "vinyl group" does not relate to a vinyl group that is part of an acrylate group and is itself a functional group.

[0040] In certain embodiments, the polyfunctional acrylate monomer can include one acrylate group, two vinyl groups, and an aromatic ring structure, such as one or more benzene rings.

[0041] The amount of the polyfunctional acrylate monomer can be at least 20 wt%, or at least 30 wt%, or at least 40 wt%, or at least 50 wt%, or at least 60 wt% based on the total weight of the polymerizable material. In another embodiment, the amount of the polyfunctional acrylate monomer can be 70 wt% or less, or 60 wt% or less, or 50 wt% or less based on the total weight of the polymerizable material. The amount of the polyfunctional acrylate monomer can be a value between any of the above minimum and maximum numbers.

[0042] In one embodiment, the polymerizable material can consist essentially of a polyfunctional vinylbenzene monomer and a polyfunctional acrylate monomer. In certain embodiments, the weight percentage ratio of the polyfunctional acrylate monomer to the polyfunctional vinylbenzene monomer can be in the range of 2:1 to 1:2, or 1.5:1 to 1:1.5. As used herein, consisting essentially of a polyfunctional vinylbenzene monomer and a polyfunctional acrylate monomer means that 1 wt% or less of the polymerizable material contains other types of polymerizable monomers, oligomers, or polymers.

[0043] In other embodiments, the polymerizable material can include other types of polymerizable compounds, such as monofunctional monomers, or polymerizable oligomers, or polymerizable polymers, in addition to the polyfunctional vinylbenzene monomer and the polyfunctional acrylate monomer. The amount of the other polymerizable compound can be at least 1 wt%, or at least 5 wt%, or at least 10 wt% based on the total weight of the polymerizable material. In another embodiment, the amount of the other polymerizable compound can be 30 wt% or less, or 20 wt% or less, or 15 wt% or less, or 10 wt% or less.

[0044] In certain embodiments, the photocurable composition may essentially not contain a maleimide monomer. As used herein, essentially not containing a maleimide monomer means that up to 0.5 wt% of the polymerizable material may be a maleimide monomer. In another embodiment, the photocurable composition may not contain a maleimide monomer.

[0045] To stabilize the polyfunctional vinylbenzene monomer in the photocurable composition (to prevent unwanted polymerization during storage), a suitable stabilizer can be added to the composition. In one embodiment, the photocurable composition can contain 4-tert-butylcatechol (TBC) as a stabilizer in an amount of at least 0.05 wt% based on the total weight of the photocurable composition. In certain embodiments, the amount of TBC can be at least 0.1 wt%, or at least 0.2 wt%, or at least 0.3 wt% based on the total weight of the photocurable composition. In another embodiment, the amount of TBC can be 1 wt% or less, or 0.5 wt% or less, or 0.3 wt% or less, or 0.2 wt% or less based on the total weight of the photocurable composition.

[0046] In certain embodiments, the photocurable composition of the present disclosure may essentially not contain a solvent.

[0047] As used herein, unless otherwise indicated, the term "solvent" refers to a compound that can dissolve or disperse a polymerizable monomer but does not itself polymerize during the photocuring of the photocurable composition. The term "substantially solvent-free" means herein that the amount of solvent is 5% by weight or less based on the total weight of the photocurable composition. In certain embodiments, the amount of solvent can be 3% by weight or less, 2% by weight or less, 1% by weight or less, or the photocurable composition may be solvent-free except for unavoidable impurities.

[0048] In another embodiment, the photocurable composition and the present disclosure can include an amount of solvent that exceeds 5% by weight based on the total weight of the photocurable composition. In certain embodiments, the amount of solvent can be at least 7% by weight, or at least 10% by weight, or at least 15% by weight, at least 20% by weight, or at least 25% by weight based on the total weight of the photocurable composition. In another embodiment, the amount of solvent can be 40% by weight or less, or 30% by weight or less, or 20% by weight or less, or 10% by weight or less based on the total weight of the photocurable composition.

[0049] In one embodiment, the curable composition of the present disclosure can have a low viscosity that enables the use of these compositions in IAP applications. In one embodiment, the viscosity of the curable composition at a temperature of 23°C can be 50 mPa·s or less, such as 40 mPa·s or less, or 30 mPa·s or less, 20 mPa·s or less, 15 mPa·s or less, or 10 mPa·s or less. In another embodiment, the viscosity can be at least 5 mPa·s, or at least 7 mPa·s. As used herein, all viscosity values relate to viscosities measured at a predetermined temperature using the Brookfield method.

[0050] In a further embodiment, the photocurable composition can contain at least one optional additive. Non-limiting examples of optional additives can be surfactants, dispersants, stabilizers, co-solvents, initiators, inhibitors, dyes, or any combination thereof.

[0051] In another embodiment, the present disclosure is directed to a laminate including a substrate and a photocurable layer overlapping the substrate, and the photocurable layer can be formed from the above-described photocurable composition.

[0052] In certain aspects, the laminate can further include one or more layers, such as an adhesive layer, between the substrate and the cured layer.

[0053] The present disclosure is further directed to a method of forming a photocurable layer. The method can include applying the above-described photocurable composition onto a substrate, contacting the photocurable composition with a template or a superstrate, irradiating the photocurable composition with light to form a photocurable layer, and removing the template or the superstrate from the photocurable layer.

[0054] In one aspect, the light irradiation can be performed with light having a wavelength of 250 nm to 760 nm. In a preferred aspect, the light irradiation can be performed with light having a wavelength of 300 nm to 450 nm.

[0055] The substrate and the cured (photocured) layer can be subjected to additional processing to form a desired article, for example, by including an etching process for transferring an image corresponding to a pattern in one or both of the cured layer and / or a patterned layer under the cured layer onto the substrate. The substrate can be further subjected to known processes and treatments for device (article) manufacturing, including, for example, curing, oxidation, layer formation, deposition, doping, planarization, etching, removal of formable materials, dicing, bonding, and packaging. In certain aspects, the substrate can be processed to manufacture a plurality of articles (devices).

[0056] The cured layer can be further used as an interlayer insulating film for semiconductor elements such as LSI, system LSI, DRAM, SDRAM, RDRAM, D-RDRAM, etc., or as a resist film used in semiconductor manufacturing processes.

[0057] As further demonstrated in the examples, surprisingly, a photocurable composition containing a specific combination of an oxime ester compound as a photoinitiator and a polyfunctional vinylbenzene as part of the polymerizable material has been found to be very suitable for IAP treatment. For example, it is possible to balance important parameters for IAP treatment such as low viscosity, UV curing speed, low shrinkage rate during UV curing to obtain a flat surface, and high thermal stability to enable downstream processing at temperatures such as 350 °C, or 400 °C, and even 450 °C.

[0058] Example The following non-limiting examples illustrate the concepts described herein.

[0059] Example 1

[0060] Preparation of photocurable IAP composition

[0061] A first set of photocurable compositions was prepared containing 50 parts by weight of 3,3'-divinylbiphenyl (DVBP), 50 parts by weight of m-xylene diacrylate (MXDA), 1 part by weight of a nonionic fluorosurfactant FS3100 (manufactured by Dupont), 0.3 part by weight of 4-tert-butylcatechol (TBC), and 1 part or 2 parts by weight of a photoinitiator. The compositions were varied by using different types and amounts of oxime ester photoinitiators.

[0062] The following oxime ester photoinitiators were used: OXE01 (see Structure 4 above); OXE02 (see Structure 2 above); and OXE03 (see Structure 3 above). Comparative compositions C1 and C2 are well-known for photocurable compositions suitable for IAP treatment and contain typical photoinitiators that are not oxime esters: Irgacure 819 and 907.

[0063] An overview of the first set of photocurable compositions is shown in Table 1.

[0064] Table 1 JPEG2025516450000008.jpg97170

[0065] The second set of the photocurable composition was prepared by mixing the following components: 40 parts by weight of 3,4’,5-trivinyl-1,1’-biphenyl (3VPH), 60 parts by weight of 3,5-divinylbenzyl acrylate (DVBA), 1 part by weight of a nonionic fluorosurfactant FS3100 (manufactured by Dupont), 0.5 part by weight of TBC, and various types and amounts of photoinitiators. The types of photoinitiators were the same as those of the first set of the photocurable composition, except that Irgacure 907 was further used as a comparative example. The amounts of the photoinitiators were varied by using 2 parts by weight, 4 parts by weight, and 6 parts by weight of the photoinitiator based on the total weight of the photocurable composition.

[0066] An overview of the second set of the photocurable composition can be shown in Table 2.

[0067] Table 2 JPEG2025516450000009.jpg97170

[0068] A further set of the comparative photocurable composition was prepared by using a combination of 60 wt% of MXDA, 35 wt% of trimethylolpropane triacrylate, and 1 wt% of a surfactant FS2000M1 as a polymerizable monomer. As photoinitiators, OXE02 and Irgacure 907 were varied in amounts of 2 wt% and 4 wt%. An overview of the composition and test results can be shown in Table 3.

[0069] Table 3 JPEG2025516450000010.jpg49170

[0070] UV shrinkage rate

[0071] The photocurable composition was cured using an Anton Paar MCR-301 rheometer connected to a UV curing system and a heater. The sample was irradiated with a mercury UV lamp having a 365 nm band filter. The light intensity was set to 38 mW / cm 2 and the UV radiation was carried out at room temperature (23 °C).

[0072] Before starting the UV radiation, the distance between the glass plate and the measuring unit was narrowed to a gap of 0.1 mm. At the start of the UV radiation, the radicals generated by the photoinitiator were consumed by the inhibitors present in the resist, so the storage modulus did not increase until all the inhibitors were consumed. This period was recorded as the induction time. The exposure to UV radiation was continued until a storage modulus of 1×10 7 Pa was obtained.

[0073] The thickness of the layer of the photocurable composition before curing was 35 microns, and the shrinkage rate was observed by tracking the change in the thickness of the layer during UV curing. In this specification, the UV shrinkage rate, also called the linear shrinkage rate, is S UV =(T p -T c ) / T p and is calculated as the percent UV shrinkage rate (S UV [%]), where T p is the thickness of the liquid film of the photocurable composition before UV curing, and T c is the thickness of the photocured film after curing (when a storage modulus of 1×10 7 Pa is reached).

[0074] As particularly seen for the photocurable compositions in Table 1 and Table 2, all the compositions prepared using the photoinitiators OXE01, OXE02, and OXE03 had a lower shrinkage rate during UV curing than the comparative compositions (C1-C8) using Irgacure 819 or Irgacure 907 at all photoinitiator concentrations.

[0075] Comparative compositions C9, C10, and C11 (see Table 3), which do not contain polyfunctional vinyl monomers but contain a combination of bifunctional acrylate MXDA and trifunctional acrylate monomers, do not have the desired low UV shrinkage rate, and it was further observed that the UV shrinkage rate of these samples exceeded 4.5%.

[0076] Induction time and curing rate

[0077] Further comparisons shown in Tables 1 and 2 are the induction time (the time until an increase in the storage modulus is measured) and the curing time (the time until a storage modulus of 1×10 7 Pa is obtained). In particular, it can be seen that the photocurable compositions containing oxime ester photoinitiators OXE01 and OXE02 were equivalent to the compositions containing photoinitiators Irgacure 819 and Irgacure 907 in terms of the induction time and the curing time (until a storage modulus of 1×10 7 Pa is obtained).

[0078] Thermal shrinkage rate

[0079] The thermal shrinkage rate was determined according to the following procedure.

[0080] First, a UV-cured layer was prepared by depositing a 500-nm-thick liquid film of the photocurable composition on a blank fused silica template. For the measurement, an Anton Paar MCR-301 rheometer connected to the above-mentioned Hamamatsu Lightningcure LC8 UV power supply was used. The liquid film was irradiated at a light intensity of 38 mW / cm 2 at 365 nm for 263 seconds, which corresponds to a curing energy dose of 10 J / cm 2 .

[0081] The photocurable film was subjected to high-temperature baking treatment by placing the UV-curable film on a hot plate having a temperature of 350 °C under nitrogen for 2 minutes. The film thickness before and after baking was measured with a JA Woollam Spectroscopic Ellipsometer M-2000 X-210. The thermal shrinkage rate (St) was calculated according to the formula: St = (T u - T b ) / T u , where T u is the thickness of the photocurable film before baking, and T b is the thickness of the film after baking.

[0082] The measured values of the thermal shrinkage rate are summarized in Table 1, Table 2, and Table 3. In particular, it can be seen that the second set of photocurable compositions summarized in Table 2 had a very low thermal shrinkage rate of less than 3% when the photoinitiator OXE02 or OXE03 was used. However, the photoinitiator OXE02 could not achieve a thermal shrinkage rate of less than 4.5 percent when the monomer combination did not contain a trifunctional vinyl monomer but instead contained a trifunctional acrylate monomer (see C9, C10, and C11 in Table 3). However, the thermal shrinkage rate when using the photoinitiator OXE02 in this series of experiments was also lower compared to the use of the photoinitiator Irgacure 907.

[0083] The best results were obtained with the combination of a biphenyl-benzene monomer containing three vinyl groups (3VPH) and the oxime photoinitiators OXE02 or OXE03, and the thermal shrinkage rate was always less than 3 percent. Without being bound by theory, the advantages of the OXE02 and OXE03 oxime ester type photoinitiators may be caused by the formation of CO 2 and CH 3 - radicals during photocuring. The small CH 3 radicals may move into the formed polymer network and reach unreacted C=C groups hidden within the network, and the released CO 2 can cause the formation of sub-nanopores, which may help prevent the polymer network from collapsing before it fully solidifies.

[0084] Viscosity

[0085] The viscosity of the photocurable composition was measured at 200 rpm using a Brookfield Viscometer LVDV-II + Pro, with a spindle size #18 and a spin rate of 135 rpm. For the viscosity test, a sample liquid of about 6 - 7 mL in an amount sufficient to cover the spindle head was applied into the sample chamber. The sample contained in the chamber was equilibrated for about 20 minutes to reach the desired measurement temperature of 23°C before the actual measurement was started. For all viscosity tests, at least three measurements were made and the average value was calculated.

[0086] The specification and drawings of the embodiments described herein are intended to provide a general understanding of the structures of the various embodiments. The specification and drawings do not comprehensively and inclusively describe all of the elements and features of the devices and systems using the structures or methods described herein. Separate embodiments may also be provided in combination in a single embodiment, and conversely, for the sake of brevity, the various features described in the context of a single embodiment may be provided separately or in any sub-combination. Further, references to values recited in ranges include each and every value within that range. Many other embodiments may be apparent to those skilled in the art only after reading this specification. Other embodiments may be used and derived from the present disclosure such that structural substitutions, logical substitutions, or other changes may be made without departing from the scope of the present disclosure. Accordingly, the present disclosure should be regarded as illustrative rather than restrictive.

Claims

1. A photocurable composition comprising a polymerizable material and at least one photoinitiator, wherein the polymerizable material is contained at a ratio of at least 85% by weight based on the total weight of the photocurable composition, the polymerizable material contains at least one polyfunctional vinylbenzene monomer, the polyfunctional vinylbenzene monomer is contained at a ratio of at least 30% by weight based on the total weight of the polymerizable material, the at least one photoinitiator contains an oxime ester compound, the photocurable composition is configured such that the film thickness change rate, expressed as a percentage, obtained by dividing the difference in film thickness before and after curing of the photocured layer formed by light irradiation at 23°C by the film thickness before curing is 4.0% or less. A photocurable composition.

2. The photocurable composition is configured such that the photocured layer formed from the photocurable composition has a heat shrinkage rate of 3.5% or less after a baking treatment at 350°C. The baking treatment includes baking the photocured layer for 2 minutes under an N ２ atmosphere on a stainless steel plate having a temperature of 350°C. The photocurable composition according to claim 1.

3. The oxime ester compound has a structure of formula (1), R １ is an aromatic ring system or a heteroaromatic ring system, and R ２ is H or C １ -C ８ alkyl, and R ３ is H or C １ -C ８ alkyl, the photocurable composition according to claim 1.

4. The oxime ester compound contains a structure of formula (2), The photocurable composition according to claim 3.

5. The oxime ester compound contains a structure of formula (3), The photocurable composition according to claim 3.

6. The photocurable composition according to claim 1, further comprising at least 0.05% by weight of 4-tert-butylcatechol (TBC).

7. The amount of the oxime ester compound is at least 1% by weight and 7% by weight or less based on the total weight of the photocurable composition. The photocurable composition according to claim 1.

8. The photocurable composition according to claim 1, wherein the at least one photoinitiator further contains a photoinitiator that is not an oxime ester compound.

9. The amount of the polymerizable material is at least 85% by weight based on the total weight of the photocurable composition. The photocurable composition according to claim 1.

10. The photocurable composition according to claim 1, wherein the polyfunctional vinylbenzene monomer contains at least three vinyl groups.

11. The photocurable composition according to claim 10, wherein the polyfunctional vinylbenzene monomer is a biphenyl compound containing three vinyl groups.

12. The photocurable composition according to claim 1, wherein the polymerizable material further contains at least one polyfunctional acrylate monomer.

13. The photocurable composition according to claim 12, wherein the polyfunctional acrylate monomer contains at least one acrylate group and at least one vinyl group.

14. The photocurable composition according to claim 12, wherein the total amount of the polyfunctional vinylbenzene monomer and the polyfunctional acrylate monomer is at least 85% by weight based on the total weight of the polymerizable material.

15. The photocurable composition according to claim 12, wherein the weight% ratio of the polyfunctional acrylate monomer to the polyfunctional vinylbenzene monomer is in the range of 2:1 to 1:

2.

16. The photocurable composition according to claim 1, wherein the viscosity of the photocurable composition is 50 mPa·s or less.

17. A method for forming a photocured layer on a substrate, comprising: a step of applying a layer of a photocurable composition on the substrate, wherein the photocurable composition contains a polymerizable material and at least one photoinitiator, the polymerizable material is contained in a proportion of at least 85% by weight based on the total weight of the photocurable composition, the polymerizable material contains at least one polyfunctional vinylbenzene monomer, the polyfunctional vinylbenzene monomer is contained in a proportion of at least 30% by weight based on the total weight of the polymerizable material, and the at least one photoinitiator contains an oxime ester compound; a step of bringing the photocurable composition into contact with a template or a superstrate; a step of irradiating the photocurable composition with light to form a photocured layer; a step of removing the template or the superstrate from the photocured layer; The method comprising the above steps.

18. The method according to claim 17, wherein the step of irradiating the photocurable composition is performed with UV light, and the UV shrinkage rate after forming the photocured layer is 4.0% or less.

19. The photocurable layer has a heat shrinkage rate of 3.5% or less after baking treatment at 350°C, and the baking treatment includes baking the photocurable layer for 2 minutes in an N ２ atmosphere on a stainless steel plate having a temperature of 350°C. The method according to claim 17.

20. A method for manufacturing an article, comprising: a step of applying a layer of a photocurable composition on a substrate, wherein the photocurable composition contains a polymerizable material and at least one photoinitiator, the polymerizable material is contained in a proportion of at least 85% by weight based on the total weight of the photocurable composition, the polymerizable material contains at least one polyfunctional vinylbenzene monomer, the polyfunctional vinylbenzene monomer is contained in a proportion of at least 30% by weight based on the total weight of the polymerizable material, and the at least one photoinitiator contains an oxime ester compound; a step of bringing the photocurable composition into contact with a template or a superstrate; a step of irradiating the photocurable composition with light to form a photocured layer; The step of removing the template or the superstrate from the photocurable layer; The step of forming a pattern on the substrate; The step of processing the substrate on which the pattern is formed in the forming step; The step of manufacturing an article from the substrate processed in the processing step; A method for manufacturing an article, comprising the above steps.

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