Photocurable composition

Abstract

A photocurable composition may include a polymerizable material and at least one photoinitiator, where the polymerizable material includes a polyfunctional vinylbenzene monomer in an amount of at least 30 wt% based on the total weight of the polymerizable material, and the at least one photoinitiator includes an oxime ester compound. The UV shrinkage rate of the photocurable composition is not more than 4.0% after the photocurable composition forms a photocurable layer at 23 DEG C; and the thermal shrinkage rate of the photo-cured layer is not greater than 3.5% after the photo-cured layer is baked at 350 DEG C.

Description

Technical Field

[0001] The present disclosure relates to photocurable compositions, and in particular to photocurable compositions suitable for inkjet-adaptive planarization. Background Art

[0002] Inkjet adaptive planarization (IAP) is a method for planarizing the surface of a substrate (e.g., a wafer containing electronic circuits) by jetting droplets of a photocurable composition on the substrate surface and bringing a flat superstrate into direct contact with the added liquid to form a flat liquid layer. The flat liquid layer typically solidifies under UV light exposure and, after removing the superstrate, a flat surface is obtained that can be subjected to subsequent processing steps, such as baking, etching, and / or additional deposition steps. Improved IAP materials are needed that result in a flat solidified layer with high thermal stability. Summary of the invention

[0003] In one embodiment, the photocurable composition may include a polymerizable material and at least one photoinitiator, wherein the polymerizable material includes at least one multifunctional vinylbenzene monomer in an amount of at least 30 weight percent, 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 to have a UV shrinkage of no more than 4.0% after forming a photocured layer at 23°C.

[0004] In another embodiment, the photocurable composition can be adapted such that the thermal shrinkage of the photocurable layer formed by the photocurable composition after baking at 350°C is not greater than 3.5%, and the baking treatment includes baking the photocurable layer on a stainless steel plate at a temperature of 350°C for 2 minutes under a N2 environment.

[0005] In one aspect, the oxime ester compound of the photocurable composition may have a structure of formula (1): Wherein R1 is an aromatic ring system or a heteroaromatic ring system, R2 is H or a C1-C8 alkyl group, and R3 is H or a C1-C8 alkyl group.

[0006] In one particular aspect, the oxime ester compound may include a structure of formula (2):

[0007] In another specific aspect, the oxime ester compound of the photocurable composition may include a structure of formula (3):

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

[0009] In another embodiment of the photocurable composition, the amount of the oxime ester compound may be at least 1 wt % and not greater than 7 wt % based on the total weight of the photocurable composition.

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

[0011] In another aspect of the photocurable composition, the amount of the polymerizable material can be at least 85 weight percent, based on the total weight of the photocurable composition.

[0012] In one embodiment, the multifunctional vinylbenzene monomer of the polymerizable material may include at least three vinyl groups. In certain aspects, the multifunctional vinylbenzene monomer may be a biphenyl compound including three vinyl groups.

[0013] In another embodiment of the photocurable composition, the polymerizable material may further include at least one multifunctional acrylate monomer. In certain specific aspects, the multifunctional acrylate monomer may include at least one acrylate group and at least one vinyl group.

[0014] In yet another aspect of the photocurable composition, the total amount of the multifunctional vinylbenzene monomer and the multifunctional acrylate monomer may be at least 85 wt % based on the total weight of the polymerizable material.

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

[0016] In another aspect, the viscosity of the photocurable composition may be no greater than 50 mPa·s.

[0017] In one embodiment, a method for forming a photocurable layer on a substrate may include: applying a layer of a photocurable composition on a substrate, wherein the photocurable composition comprises a polymerizable material and at least one photoinitiator, the polymerizable material comprising at least one multifunctional vinylbenzene monomer in an amount of at least 30 weight percent, based on the total weight of the polymerizable material; and the at least one photoinitiator comprises an oxime ester compound; contacting the photocurable composition with a template or a cover layer; irradiating the photocurable composition with light to form a photocurable layer; and removing the template or the cover layer from the photocurable layer.

[0018] In one aspect of the method, the photocurable composition may be irradiated with UV light, and a UV shrinkage rate after forming a photocured layer may be no greater than 4.0%.

[0019] In another aspect of the method, the photocurable layer may have a thermal shrinkage of no more than 3.5% after a baking treatment at 350° C., the baking treatment comprising baking the photocurable layer on a stainless steel plate at a temperature of 350° C. under N 2 for 2 minutes.

[0020] In another embodiment, a method for manufacturing an article may include: applying a layer of a photocurable composition on a substrate, wherein the photocurable composition comprises a polymerizable material and at least one photoinitiator, the polymerizable material comprising at least one multifunctional vinylbenzene monomer in an amount of at least 30 weight percent, based on the total weight of the polymerizable material; and the at least one photoinitiator comprises an oxime ester compound; contacting the photocurable composition with a template or a cover layer; irradiating the photocurable composition with light to form a photocured layer; removing the template or the cover layer from the photocured layer; forming a pattern on a substrate; treating the substrate on which the pattern has been formed in the process; and manufacturing an article from the substrate treated in the process. DETAILED DESCRIPTION

[0021] The following description is provided to help understand the teaching disclosed herein and the following description will focus on specific embodiments and implementations of the teaching. This focus is provided to help describe the teaching and should not be interpreted as a limitation on the scope or applicability of the teaching.

[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 the invention belongs. The materials, methods, and examples are illustrative only and are not intended to be limiting. To the extent not described herein, many details about specific materials and processing operations are conventional and can be found in textbooks and other sources in the field of imprinting and lithography.

[0023] As used herein, the terms "comprises," "comprising," "including," "including," "having," "having" or any other variation thereof, are intended to cover a 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 but may include other features not expressly listed or inherent to such process, method, article, or apparatus.

[0024] As used herein, and unless expressly stated to the contrary, "or" means "inclusive or" rather than "exclusive or." For example, a condition A or B satisfies any of the following: A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B is true (or exists), and both A and B are true (or exist).

[0025] In addition, "a" or "an" is used to describe the elements and components described herein. This is done only for convenience and to give a general sense of the scope of the invention. The description should be interpreted as including one or at least one, and the singular also includes the plural, unless it is obvious that it means otherwise.

[0026] The present disclosure relates to a photocurable composition including a polymerizable material and a photoinitiator, wherein the photoinitiator may include an oxime ester compound, and the polymerizable material may include a multifunctional vinylbenzene monomer in an amount of at least 30 wt%.

[0027] The photocurable composition of the present disclosure has the advantage of being useful in inkjet adaptive planarization (IAP) processing due to low viscosity, low shrinkage during curing, and extremely high thermal stability.

[0028] In one embodiment, the photocurable composition of the present disclosure may be adapted to have a UV shrinkage of not more than 4.0%, or not more than 3.5%, or not more than 3.0% at 23° C. after forming a photocured layer.

[0029] In another embodiment, the shrinkage of the photocurable layer formed from the photocurable composition after baking at 350° C. is no greater than 3.5%, and the baking treatment includes baking the photocurable layer on a stainless steel plate at a temperature of 350° C. for 2 minutes. In other aspects, the linear shrinkage after baking at 350° C. may be no greater than 3.0%, no greater than 2.5%, no greater than 2.0%, no greater than 1.5%, or no greater than 1.0%, or no greater than 0.5%.

[0030] In one embodiment, the oxime ester compound of the photoinitiator may have the structure of formula (1): Wherein R1 is an aromatic ring system or a heteroaromatic ring system, R2 is H or a C1-C8 alkyl group, and R3 is H or a C1-C8 alkyl group.

[0031] In a particular embodiment, the oxime ester compound may have the structure of formula (2):

[0032] In another specific embodiment, the oxime ester compound may have the structure of formula (3):

[0033] In another specific aspect, the oxime ester compound may have a structure of formula (4):

[0034] The amount of the oxime ester compound of the photoinitiator may 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. On the other hand, the amount of the oxime ester compound may be no more than 10 wt %, or no more than 8 wt %, or no more than 7 wt %, or no more than 6 wt %, or no more than 5 wt %, or no more than 4 wt %, based on the total weight of the photocurable composition. The amount of the oxime ester compound of the photoinitiator may be a value between any of the above minimum and maximum numbers.

[0035] In certain aspects, the photoinitiator of the photocurable composition may further include at least one photoinitiator that is not an oxime ester compound.

[0036] The polymerizable material of the photocurable composition may be the major amount of the composition. In one embodiment, the amount of the polymerizable material may 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 multifunctional vinylbenzene of term polymerizable material refers to a polymerizable monomer containing one or more benzene rings and at least two vinyls directly connected to the one or more benzene rings. In some aspects, multifunctional vinylbenzene may include at least three vinyls or at least four vinyls. In particular aspects, multifunctional vinylbenzene monomer may include two benzene rings and three vinyls connected to the benzene ring. Non-limiting examples of such monomers may be 3,4',5-trivinyl-1,1'biphenyl (3VPH).

[0038] In one embodiment, the amount of the multifunctional vinylbenzene monomer can be at least 30 weight percent, such as at least 35 weight percent, at least 40 weight percent, at least 50 weight percent, at least 60 weight percent, at least 70 weight percent, at least 80 weight percent, at least 90 weight percent, or at least 95 weight percent, based on the total weight of the polymerizable material. On the other hand, the amount of the multifunctional vinylbenzene monomer can be no greater than 98 weight percent, or no greater than 95 weight percent, or no greater than 90 weight percent, or no greater than 80 weight percent, or no greater than 70 weight percent, or no greater than 60 weight percent, or no greater than 50 weight percent, based on the total weight of the polymerizable material. The amount of the multifunctional vinylbenzene monomer can be a value between any of the above minimum and maximum numbers.

[0039] In another embodiment, the polymerizable material may also include a multifunctional acrylate monomer. On the one hand, the multifunctional acrylate monomer may include at least two acrylate groups, or at least three acrylate groups, or at least four acrylate groups. On the other hand, the multifunctional acrylate monomer may include at least one acrylate group and at least one vinyl group. As used herein, the term acrylate monomer refers to substituted and unsubstituted acrylate monomers. Non-limiting examples of substituted acrylate monomers may be C1-C8 alkyl acrylates, such as methacrylate or ethyl acrylate. In addition, as used herein, the term "vinyl" does not refer to a vinyl group that is a part of an acrylate group but is itself a functional group.

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

[0041] The amount of the multifunctional 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. On the other hand, the amount of the multifunctional acrylate monomer can be no greater than 70 wt%, or no greater than 60 wt%, or no greater than 50 wt%, based on the total weight of the polymerizable material. The amount of the multifunctional acrylate monomer can be a value between any of the above minimum and maximum numbers.

[0042] In one aspect, the polymerizable material may consist essentially of multifunctional vinylbenzene monomers and multifunctional acrylate monomers. In a particular aspect, the weight % ratio of multifunctional vinylbenzene monomers to multifunctional acrylate monomers may be in the range of 2:1 to 1:2, or in the range of 1.5:1 to 1:1.5. As used herein, consisting essentially of multifunctional vinylbenzene monomers and multifunctional acrylate monomers means that no more than 1 weight % of the polymerizable material includes other types of polymerizable monomers, oligomers, or polymers.

[0043] In other aspects, in addition to the multifunctional vinylbenzene monomer and the multifunctional acrylate monomer, the polymerizable material may also include other types of polymerizable compounds, such as monofunctional monomers, or polymerizable oligomers, or polymerizable polymers. The amount of the other polymerizable compounds may 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 aspect, the amount of the other polymerizable compounds may be no greater than 30 wt%, or no greater than 20 wt%, or no greater than 15 wt%, or no greater than 10 wt%.

[0044] In certain aspects, the photocurable composition can be substantially free of maleimide monomers. Substantially free of maleimide monomers means herein that no more than 0.5% by weight of the polymerizable material can be maleimide monomers. In another aspect, the photocurable composition can be free of maleimide monomers.

[0045] In order to stabilize the multifunctional vinylbenzene monomer in the photocurable composition (to prevent undesirable polymerization during storage), a suitable stabilizer can be added to the composition. On the one hand, the photocurable composition can include at least 0.05% by weight of 4-tert-butylcatechol (TBC) as a stabilizer, based on the total weight of the photocurable composition. In certain aspects, the amount of TBC can be at least 0.1% by weight, or at least 0.2% by weight, or at least 0.3% by weight, based on the total weight of the photocurable composition. On the other hand, the amount of TBC may be not more than 1% by weight, or not more than 0.5% by weight, or not more than 0.3% by weight, or not more than 0.2% by weight, based on the total weight of the photocurable composition.

[0046] In certain embodiments, the photocurable compositions of the present disclosure may be substantially free of solvents.

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

[0048] In another aspect, the photocurable composition and the present disclosure may contain a solvent in an amount greater than 5 wt %, based on the total weight of the photocurable composition. In a particular aspect, the amount of solvent may be at least 7 wt %, or at least 10 wt %, or at least 15 wt %, at least 20 wt %, or at least 25 wt %, based on the total weight of the photocurable composition. In another aspect, the amount of solvent may be no greater than 40 wt %, or no greater than 30 wt %, or no greater than 20 wt %, or no greater than 10 wt %, based on the total weight of the photocurable composition.

[0049] In one embodiment, the curable compositions of the present disclosure may have a low viscosity, which may allow the use of these compositions in IAP applications. In one aspect, the viscosity of the curable composition at a temperature of 23° C. may be no greater than 50 mPa·s, such as no greater than 40 mPa·s, or no greater than 30 mPa·s, no greater than 20 mPa·s, no greater than 15 mPa·s, or no greater than 10 mPa·s. In another aspect, the viscosity may be at least 5 mPa·s, or at least 7 mPa·s. All viscosity values ​​used herein refer to the viscosity measured by the Brookfield method at a given temperature.

[0050] In yet another aspect, the photocurable composition may contain at least one optional additive. Non-limiting examples of the optional additive may be a surfactant, a dispersant, a stabilizer, a co-solvent, an initiator, an inhibitor, a dye, or any combination thereof.

[0051] In another embodiment, the present disclosure relates to a laminated body including a substrate and a photocurable layer covering the substrate, wherein the photocurable layer can be formed from the above-mentioned photocurable composition.

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

[0053] The present disclosure also relates to a method for forming a photocurable layer. The method may include applying the above-mentioned photocurable composition above a substrate; contacting the photocurable composition with a template or a cover layer; irradiating the photocurable composition with light to form a photocurable layer; and removing the template or the cover layer from the photocurable layer.

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

[0055] The substrate and the solidified (photocured) layer may be subjected to additional processing to form the desired product, for example, including an etching process to transfer an image to the substrate, which corresponds to the pattern in one or both of the solidified layer and / or the pattern layer below the solidified layer. The substrate may be further subjected to known steps and processes for device (product) manufacturing, including, for example, curing, oxidation, layer formation, deposition, doping, planarization, etching, formable material removal, cutting, bonding, and packaging, etc. In certain aspects, the substrate can be processed to prepare a variety of products (devices).

[0056] The cured layer is further used as an interlayer insulating film of a semiconductor device such as LSI, system LSI, DRAM, SDRAM, RDRAM, or D-RDRAM, or as a resist film used in a semiconductor manufacturing process.

[0057] As further demonstrated in the Examples, it was surprisingly found that certain combinations of photocurable compositions including an oxime ester compound as a photoinitiator and a multifunctional vinylbenzene as part of the polymerizable material can be very suitable for IAP processing. Parameters important for IAP processing, such as low viscosity, UV curing speed, low shrinkage during UV curing to obtain a flat surface, and high thermal stability can be balanced to allow downstream processing at temperatures of 350°C, or 400°C, or even 450°C. Example

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

[0059] Example 1

[0060] Preparation of photocurable IAP compositions

[0061] A first set of photocurable compositions was prepared, comprising 50 parts by weight of 3,3'-divinylbiphenyl (DVBP), 50 parts by weight of m-xylene diacrylate (MXDA), 1 part by weight of nonionic fluorosurfactant FS 3100 (from DuPont), 0.3 parts by weight of 4-tert-butylcatechol (TBC), and 1 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 contained typical photoinitiators that are well known for photocurable compositions suitable for IAP processing and are not oxime esters: Irgacure 819 and 907.

[0063] Table 1 shows the outline of the first group of photocurable compositions.

[0064] Table 1: S1 S2 S3 S4 S5 C1 C2 OXE01 1 2 OXE02 1 2 OXE03 2 Irgacure 819 2 Irgacure 907 2 UV shrinkage [%] 2.60 4.0 3.70 4.00 4.00 4.30 4.9 Thermal shrinkage [%] 22.92 9.77 9.12 10.63 Induction time [s] 15 105 11.5 25.6 50 4.4 17.9 Curing time[s] 76 319 31.1 184 373 9.6 48.5 Viscosity [mPa·s] 13 13 13 13 13 13 13

[0065] The second set of photocurable compositions was prepared by combining the following ingredients: 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 nonionic fluorinated surfactant FS 3100 (from DuPont), 0.5 parts by weight of TBC, and different types and amounts of photoinitiators. The type of photoinitiator was the same as that in the first set of photocurable compositions, except that Irgacure 907 was further used as a comparative example. The amount of the photoinitiator was varied by using 2, 4, and 6 parts by weight of the photoinitiator, based on the total weight of the photocurable composition.

[0066] In Table 2 a summary of the photocurable compositions of the second group can be seen.

[0067] Table 2:

[0068] Another set of comparative photocurable compositions was prepared by using a combination of 60 wt% MXDA and 35 wt% trimethylolpropane triacrylate and 1 wt% surfactant FS2000M1 as polymerizable monomers. The photoinitiator was changed to OXE02 and Irgacure 907 in amounts of 2 wt% and 4 wt%. A summary of these compositions and test results can be seen in Table 3.

[0069] Table 3: C9 C10 C11 OXE02 2 Irgacure 907 2 4 UV shrinkage [%] 5.8 4.7 4.6 Thermal shrinkage [%] 7.08 5.65 4.55 Viscosity [mPa·s] 17 17 17

[0070] UV shrinkage

[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 with a 365 nm band filter. The light intensity was set to 38 mW / cm 2 , UV irradiation was carried out at room temperature (23°C).

[0072] Before starting UV irradiation, the distance between the glass plate and the measuring cell was reduced to a gap of 0.1 mm. At the beginning of UV irradiation, the free radicals generated by the photoinitiator are consumed by the inhibitors present in the resist, so the storage modulus will not increase until all the inhibitors disappear. This period of time is recorded as the induction time. Continue UV irradiation until 1×10 7 Storage modulus in Pa.

[0073] Before curing, the layer thickness of the photocurable composition was 35 microns, and the shrinkage was observed by tracking the change in layer thickness during UV curing. The percentage UV shrinkage (S uv [%]) to calculate UV shrinkage (also referred to as linear shrinkage in this article): S uv =(T p -T c ) / T p , where T p is the film thickness of the photocurable composition before UV curing, T c is the thickness of the cured photocured film (when it reaches 1×10 7 Pa storage modulus).

[0074] It can be seen in particular for the photocurable compositions in Tables 1 and 2 that, at all photoinitiator concentrations, the compositions made using photoinitiators OXE01, OXE02 and OXE03 have lower shrinkage during UV curing than the comparative compositions (C1-C8) using photoinitiators Irgacure 819 or Irgacure 907.

[0075] It can be further observed that comparative compositions C9, C10 and C11 (see Table 3), which do not include a combination of a multifunctional vinyl monomer and a multifunctional acrylate monomer but include a combination of a difunctional acrylate MXDA and a trifunctional acrylate monomer, do not have the desired low UV shrinkage; the UV shrinkage of these samples is greater than 4.5%.

[0076] Induction time and curing speed

[0077] Other comparisons shown in Tables 1 and 2 are the induction time (the time until the storage modulus increase is measured) and the curing time (the time until a 1×10 7 Pa storage modulus). It can be seen that the photocurable compositions containing oxime ester photoinitiators OXE01 and OXE02 have a short induction time and curing time (until 1×10 7 Pa) is comparable to the compositions containing photoinitiators Irgacure 819 and Irgacure 907.

[0078] Thermal shrinkage

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

[0080] First, a UV-curable layer was prepared by depositing a 500 nm thick film of the photocurable composition onto a blank fused quartz template. For the measurement, an AntonPaar MCR-301 rheometer connected to a Hamamatsu Lightningcure LC8 UV source as described above was used. The rheometer was set at 365 nm at 38 mW / cm 2 The light intensity irradiated the liquid film for 263 seconds, which corresponds to 10 J / cm 2 The curing energy dose.

[0081] The photocured film was subjected to high temperature baking by placing the UV cured film on a hot plate at 350°C for two minutes under nitrogen. The film thickness before and after baking was measured using a JA Woollam Spectroscopic Ellipsometer M-2000X-210. The heat shrinkage (St) was calculated according to the following equation: St = (T u -T b ) / T u , where T uis the thickness of the photocured film before baking, T b is the film thickness after baking.

[0082] The measured heat shrinkage values ​​are summarized in Tables 1, 2 and 3. It can be seen that the second group of photocurable compositions summarized in Table 2, in particular, have extremely low heat shrinkages of less than 3% if photoinitiator OXE02 or OXE03 is used. However, if the monomer combination does not include a trifunctional vinyl monomer but includes a trifunctional acrylate monomer, photoinitiator OXE02 cannot achieve a heat shrinkage of less than 4.5%, see C9, C10 and C11 of Table 3. However, the heat shrinkage when using photoinitiator OXE02 in this group of experiments is also lower than when using photoinitiator Irgacure907.

[0083] The best results were obtained using a combination of a trivinyl-containing biphenyl-benzene monomer (3VPH) and oxime photoinitiators OXE02 or OXE03, where the thermal shrinkage was consistently below 3%. Without being bound by theory, the advantage of OXE02 and OXE03 oxime ester-type photoinitiators may be due to the formation of CO2 and CH3 radicals during photocuring. Small CH3 radicals can migrate into the formed polymer network, reaching unreacted C=C groups hidden in the network; and the released CO2 may lead to the formation of sub-nanometer pores, which helps prevent the polymer network from collapsing before complete solidification.

[0084] Viscosity

[0085] The viscosity of the photocurable composition was measured using a Brookfield viscometer LVDV-II+Pro at 200 rpm, with a spindle size of #18 and a rotation speed of 135 rpm. For the viscosity test, about 6-7 ml of sample liquid was added to the sample chamber, enough to cover the spindle head. Before starting the actual measurement, the sample contained in the chamber was equilibrated for about 20 minutes to reach the desired measurement temperature of 23°C. For all viscosity tests, at least three measurements were performed and the average value was calculated.

[0086] The detailed description and explanation of the embodiments described herein are intended to provide a general understanding of the structure of various embodiments. The detailed description and explanation are not intended to serve as a detailed and comprehensive description of all elements and features of the equipment and systems using the structures or methods described herein. Different embodiments may also be provided in combination in a single embodiment, and on the contrary, for simplicity, the various features described in the scene of a single embodiment may also be provided independently or in any sub-combination. In addition, the values ​​described in the reference range include each and each value within the range. Only after reading this specification, the technician may be aware of many other embodiments. Other embodiments may be used and derived from the present disclosure, so that structural replacement, logical replacement or other changes may be performed without departing from the scope of the present disclosure. Therefore, the present disclosure should be considered to be illustrative and not restrictive.

Claims

1. A photocurable composition comprising a polymerizable material and at least one photoinitiator, wherein The polymeric material comprises at least one multifunctional vinylbenzene monomer in an amount of at least 30 weight percent, based on the total weight of the polymeric material; The at least one photoinitiator comprises an oxime ester compound; and The photocurable composition is adapted to have a UV shrinkage of no more than 4.0% after forming a photocured layer at 23°C.

2. The photocurable composition according to claim 1, wherein the photocurable composition is adapted to have a thermal shrinkage rate of no more than 3.5% for a photocurable layer formed by the photocurable composition after baking at 350°C, and the baking treatment comprises baking the photocurable layer on a stainless steel plate at a temperature of 350°C for 2 minutes under a N2 environment.

3. The photocurable composition according to claim 1, wherein the oxime ester compound has a structure of formula (1): Wherein R1 is an aromatic ring system or a heteroaromatic ring system, R2 is H or a C1-C8 alkyl group, and R3 is H or a C1-C8 alkyl group.

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

5. The photocurable composition according to claim 3, wherein the oxime ester compound comprises a structure of formula (3):

6. The photocurable composition according to claim 1, further comprising at least 0.05 wt% of 4-tert-butylcatechol (TBC). 7 . The photocurable composition according to claim 1 , wherein the amount of the oxime ester compound is at least 1 wt % and not more than 7 wt % based on the total weight of the photocurable composition.

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

9. The photocurable composition of claim 1, wherein the amount of the polymerizable material is at least 85 wt% based on the total weight of the photocurable composition.

10. The photocurable composition according to claim 1, wherein the multifunctional vinylbenzene monomer includes at least three vinyl groups. 11 . The photocurable composition according to claim 10 , wherein the polyfunctional vinylbenzene monomer is a biphenyl compound including three vinyl groups.

12. The photocurable composition according to claim 1, wherein the polymerizable material further comprises at least one multifunctional acrylate monomer. 13 . The photocurable composition according to claim 12 , wherein the multifunctional acrylate monomer comprises at least one acrylate group and at least one vinyl group.

14. The photocurable composition of claim 12, wherein the total amount of the multifunctional vinylbenzene monomer and the multifunctional acrylate monomer is at least 85 wt% based on the total weight of the polymerizable material. 15 . The photocurable composition of claim 12 , wherein a weight % ratio of the multifunctional vinylbenzene monomer to the multifunctional acrylate 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 not more than 50 mPa·s.

17. A method for forming a photocurable layer on a substrate, the method comprising: applying a layer of a photocurable composition on a substrate, wherein the photocurable composition comprises a polymerizable material and at least one photoinitiator, the polymerizable material comprising at least one multifunctional vinylbenzene monomer in an amount of at least 30 weight percent, based on the total weight of the polymerizable material; and the at least one photoinitiator comprises an oxime ester compound; contacting the photocurable composition with a template or a cover layer; irradiating the photocurable composition with light to form a photocured layer; and Remove the template or cover layer from the photocured layer. 18 . The method according to claim 17 , wherein the photocurable composition is irradiated with UV light, and a UV shrinkage after forming the photocured layer is not more than 4.0%.

19. The method according to claim 17, wherein the photocurable layer has a thermal shrinkage of no more than 3.5% after a baking treatment at 350°C, wherein the baking treatment comprises baking the photocurable layer on a stainless steel plate at a temperature of 350°C under N2 for 2 minutes.

20. A method of manufacturing an article, the method comprising: applying a layer of a photocurable composition on a substrate, wherein the photocurable composition comprises a polymerizable material and at least one photoinitiator, the polymerizable material comprising at least one multifunctional vinylbenzene monomer in an amount of at least 30 weight percent, based on the total weight of the polymerizable material; and the at least one photoinitiator comprises an oxime ester compound; contacting the photocurable composition with a template or a cover layer; irradiating the photocurable composition with light to form a photocured layer; removing the template or cover layer from the light-cured layer; forming a pattern on a substrate; treating a substrate on which a pattern has been formed; as well as Articles are manufactured from the substrate treated in this process.

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