Photosensitive resin composition, dry film, cured product, printed circuit board, and laminate

Abstract

A photosensitive resin composition comprises: (A) a carboxyl-containing resin without aromatic rings; (B) an inorganic filler; and (E) a photopolymerization initiator of a compound containing a trimethylbenzylphosphine oxide group having at least one PO bond. The combination of the four components of the photosensitive resin composition significantly reduces the gas release of the photopolymerization initiator, thus addressing yellowing and incomplete curing of silicone sealants and increasing the reaction rate of the silicone sealant. It also reduces the amount of gas released from the photopolymerization initiator to the protective film and eliminates the need for a firing process after reflow to increase reflectivity, thereby solving power consumption-related problems. The composition exhibits high HAST resistance and reflectivity after HAST testing, and the reduction in reflectivity under high temperature / high humidity conditions can be suppressed. Therefore, these properties of the photosensitive resin composition enable the produced solder resist to perform excellently, allowing the photosensitive resin composition to effectively provide openings for the solder resist and facilitating the realization of a high-efficiency backlight unit through a solder resist with high reflectivity.

Description

Technical Field

[0001] The present disclosure relates to a photosensitive resin composition, a dry film, a cured product, a printed circuit board, and a laminate. The dry film comprises a photosensitive resin layer formed by coating and drying the photosensitive resin composition on a first film, the cured product is obtained by curing the photosensitive resin layer of the dry film, and the printed circuit board and the laminate each comprise the cured product. Prior Art

[0002] For printed circuit boards used in electronic devices, etc., when electronic components are mounted on the printed circuit board, a solder resist layer is generally formed on the area of ​​the board with the circuit pattern except for the connection holes in order to prevent solder from adhering to unnecessary parts and to prevent the circuit conductors from being exposed and corroded due to oxidation or moisture.

[0003] With the lightweight and miniaturization of electronic devices, printed circuit boards have recently had high precision and high density. Recently, the solder mask layer is usually formed by applying a photosensitive resin composition to a substrate, forming a pattern through exposure and development, and then curing the patterned resin through heating or light irradiation, which is the so-called photo solder mask.

[0004] The above-mentioned liquid photosensitive resin composition contains a solvent, and the production process requires repeated printing and composition drying processes, resulting in long working time and being environmentally unfriendly.

[0005] Instead of using a liquid photosensitive resin composition, the use of so-called photosensitive dry film to form a solder resist layer has been proposed. This allows for the omission of the drying process after applying the composition. Lamination using dry film reduces working time, significantly shortening the manufacturing process and improving productivity, while also enabling the effective use of solder resist even on film boards.

[0006] This type of dry film typically comprises a laminated structure, in which a solder mask layer, a photosensitive resin layer, is formed on a first film, serving as a substrate, and a second film, for example, is bonded to this layer for protection. During use, after the second film is peeled off, the dry film is hot-pressed onto the circuit board, and the first film is exposed to light, peeled off, and then developed, forming a patterned solder mask layer. Compared to using a liquid photosensitive resin composition as described above, using a dry film to form the solder mask layer not only eliminates the need for drying the composition but also improves hole-filling performance in recessed areas on the board surface. This is because pressing the dry film onto the board makes it less likely that air bubbles will be introduced between the board and the solder mask layer. Furthermore, using a dry film to form the solder mask layer ensures excellent film flatness, enabling efficient wafer mounting and achieving high resolution.

[0007] At the same time, the white solder resist layer has a higher reflectivity than the colored solder resist layer. Therefore, when the solder resist layer is formed using a dry film by the same method as described above, light is reflected from the surface of the solder resist layer during exposure, so it is difficult for light to penetrate to the lower part of the solder resist layer, and a phenomenon in which the upper part is larger than the lower part (halation) occurs on the surface, making it difficult to realize the pattern (for example, see Patent Document 1).

[0008] The solder resist layer also acts as a permanent protective film for the circuit board, so the solder resist composition is required to have various properties, such as alkali developability and solder heat resistance.

[0009] Furthermore, in addition to meeting the requirements as a general solder mask, the white solder mask must also have high reflectivity to minimize the reduction of reflectivity during the manufacturing process and prevent the cured product from yellowing when exposed to heat and light.

[0010] What is needed: a photosensitive resin composition that not only meets the basic requirements for a solder mask, but also meets the additional requirements for a white solder mask, and has higher reflectivity and excellent yellowing resistance compared to the prior art; a dry film comprising the solder mask, which can solve unique problems arising in the solder mask manufacturing process; and a method for manufacturing a printed circuit board.

[0011] (Patent Document 1) Korean Patent Publication No. 10-2022-0086524. Summary of the Invention

[0012] Conventional photopolymerization initiators (e.g., 2,4,6-trimethylbenzoyldiphenylphosphine oxide (TPO)) contained in photosensitive resin compositions used to form solder resists generate a large amount of outgassing. When this outgassing diffuses into the adjacent silicone sealant, the transparent silicone sealant may yellow, reducing reflectivity and causing incomplete curing of the silicone sealant. These drawbacks lead to long-term reliability issues for the board. Furthermore, the photopolymerization initiator can migrate not only to the silicone sealant but also to adjacent boards.

[0013] To remove outgassing from the photopolymerization initiator, one approach has been to add a firing step (e.g., curing at 150°C for 6 hours) after a reflow step (e.g., 260°C for 10 seconds). However, when the photopolymerization initiator is used for backlight units or similar purposes, this firing step significantly reduces reflectivity, leading to increased power consumption to improve reflectivity after wafer mounting. In other words, the number of steps may increase, and reflectivity may also decrease.

[0014] Furthermore, a protective film (PF) can be placed over the solder resist layer before the firing process to remove the photopolymerization initiator. This protective film is used to minimize outgassing of the photopolymerization initiator after solder resist preparation and before the subsequent firing process, and is removed by peeling before the firing process. Protective films are used for this purpose because they effectively remove photopolymerization initiators due to their high affinity for them. However, this requires two steps, namely the application of this protective film and the firing process, and does not address the reduction in reflectivity.

[0015] Various embodiments of the present disclosure provide a photosensitive resin composition comprising: (A) a carboxyl-containing resin without an aromatic ring; (B) an inorganic filler and / or (C) a mercapto-modified (meth)acrylate; and (E) a photopolymerization initiator of a compound containing a trimethylbenzylphosphine oxide group and having at least one PO bond.

[0016] According to the photosensitive resin composition of the present disclosure, outgassing of the photopolymerization initiator can be significantly reduced to solve the yellowing and incomplete curing of the silicone sealant and increase the reaction rate of the silicone sealant. In addition, the amount of outgassing generated by the photopolymerization initiator can be suppressed to reduce the amount of outgassing transferred to the protective film, and the firing process after the reflow process can be omitted to increase the reflectivity, thereby solving problems related to power consumption. In addition, the photosensitive resin composition of the present disclosure can exhibit excellent resistance to the Highly Accelerated Stress Test (HAST), high reflectivity after reflow, UV testing or HAST testing, and suppress the reduction of reflectivity under high temperature / high humidity conditions. These characteristics of the photosensitive resin composition of the present disclosure enable the produced solder resist to perform excellently.

[0017] Various embodiments of the present disclosure provide a dry film, a cured product, a printed circuit board, and a laminated board, all using the photosensitive resin composition.

[0018] According to one aspect of the present disclosure, a photosensitive resin composition is provided.

[0019] The photosensitive resin composition according to one embodiment of the present disclosure may include: (A) a carboxyl-containing resin without an aromatic ring; (B) an inorganic filler; and (E) a photopolymerization initiator of a trimethylbenzylphosphine oxide group-containing compound having at least one PO bond.

[0020] In the photosensitive resin composition according to one embodiment of the present disclosure, the photopolymerization initiator (E) of a trimethylbenzylphosphine oxide group-containing compound having at least one PO bond may include a *-C(=O)-P(=O)R1-O-*' portion (wherein R1 is an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, or a cyclic group having 5 to 20 carbon atoms).

[0021] In the photosensitive resin composition according to one embodiment of the present disclosure, the photopolymerization initiator (E) of the trimethylbenzylphosphine oxide group-containing compound having at least one PO bond may be a trimethylbenzylphosphine oxide group-containing polymer.

[0022] In the photosensitive resin composition according to one embodiment of the present disclosure, the polymer containing a trimethylbenzylphosphine oxide group may have a weight average molecular weight (Mn) of 900 g / mol or more.

[0023] In the photosensitive resin composition according to one embodiment of the present disclosure, the polymer containing a trimethylbenzylphosphine oxide group can be represented by the following Chemical Formula 1:

[0024] <Chemical Formula 1> a = 0 to 100, b = 0 to 100, and c = 0 to 100.

[0025] In the photosensitive resin composition according to one embodiment of the present disclosure, the (E) photopolymerization initiator of the trimethylbenzylphosphine oxide group-containing compound having at least one PO bond may include an alkoxy group.

[0026] In the photosensitive resin composition according to one embodiment of the present disclosure, the (E) photopolymerization initiator of the trimethylbenzylphosphine oxide group-containing compound having at least one PO bond may include an ethoxy group.

[0027] In the photosensitive resin composition according to one embodiment of the present disclosure, the photopolymerization initiator (E) of a trimethylbenzylphosphine oxide group-containing compound having at least one PO bond may be represented by the following Chemical Formula 2:

[0028] <Chemical Formula 2>

[0029] In the photosensitive resin composition according to one embodiment of the present disclosure, the content of the photopolymerization initiator (E) a trimethylbenzylphosphine oxide group-containing compound having at least one PO bond may be 0.01 wt % to 10 wt % relative to the total weight of the composition.

[0030] In the photosensitive resin composition according to one embodiment of the present disclosure, (A) the carboxyl group-containing resin having no aromatic ring may have an unsaturated double bond.

[0031] In the photosensitive resin composition according to one embodiment of the present disclosure, the photosensitive resin composition may further include (D) a resin containing an aromatic ring.

[0032] In the photosensitive resin composition according to one embodiment of the present disclosure, (D) the resin containing an aromatic ring may be a melamine resin, a silicone resin, or a resin having a styrene main chain.

[0033] In the photosensitive resin composition according to one embodiment of the present disclosure, the photosensitive resin composition may further include (C) mercapto-modified (meth)acrylate.

[0034] In the photosensitive resin composition according to one embodiment of the present disclosure, the photosensitive resin composition may further include (F) a silane coupling agent.

[0035] In the photosensitive resin composition according to one embodiment of the present disclosure, the photosensitive resin composition may further include (G) a resin having a urethane bond.

[0036] In the photosensitive resin composition according to one embodiment of the present disclosure, the outgassing content of the photosensitive resin composition measured by thermal desorption spectroscopy (TDS) and gas chromatography-mass spectrometry (GC-MS) may be 1000 ppm or less relative to the photopolymerization initiator (E) of a trimethylbenzylphosphine oxide group-containing compound having at least one PO bond.

[0037] In the photosensitive resin composition according to one embodiment of the present disclosure, the content of phosphorus may be 500 ppm to 5000 ppm.

[0038] The photosensitive resin composition according to one embodiment of the present disclosure may include: (A) a carboxyl-containing resin without an aromatic ring; (C) a mercapto-modified (meth)acrylate; and (E) a photopolymerization initiator of a trimethylbenzylphosphine oxide group-containing compound having at least one PO bond.

[0039] In the photosensitive resin composition according to one embodiment of the present disclosure, the photosensitive resin composition may further include (D) a resin containing an aromatic ring.

[0040] In the photosensitive resin composition according to one embodiment of the present disclosure, the photosensitive resin composition may further include (F) a silane coupling agent.

[0041] In the photosensitive resin composition according to one embodiment of the present disclosure, the photosensitive resin composition may further include (G) a resin having a urethane bond.

[0042] The dry film according to one embodiment of the present disclosure may have a photosensitive resin layer formed by coating the photosensitive resin composition on a first film and drying the coating.

[0043] According to one embodiment of the present disclosure, a cured product can be obtained by curing the photosensitive resin composition or a photosensitive resin layer for a dry film obtained from the photosensitive resin composition.

[0044] A printed circuit board according to an embodiment of the present disclosure may include the cured product as a solder resist.

[0045] According to an embodiment of the present disclosure, the printed circuit board may further include a silicone sealant disposed on the solder resist.

[0046] In a printed circuit board according to one embodiment of the present disclosure, the silicone sealant includes an upper sealant region and a lower sealant region, and the content of the photopolymerization initiator of the (E) trimethylbenzylphosphine oxide group-containing compound having at least one PO bond contained in the upper sealant region or the lower sealant region is 1000 ppm or less relative to the content of the photopolymerization initiator of the (E) trimethylbenzylphosphine oxide group-containing compound having at least one PO bond contained in the solder resist.

[0047] A laminate according to one embodiment of the present disclosure may include: the cured product; and a protective film.

[0048] In the laminate according to one embodiment of the present disclosure, the content of the photopolymerization initiator of the (E) trimethylbenzylphosphine oxide group-containing compound having at least one PO bond contained in the protective film is 1000 ppm or less relative to the content of the photopolymerization initiator of the (E) trimethylbenzylphosphine oxide group-containing compound having at least one PO bond contained in the solder resist.

[0049] According to some embodiments of the present disclosure, photosensitive resin compositions can significantly reduce outgassing from photopolymerization initiators, addressing yellowing and incomplete curing of silicone sealants and improving the reaction rate of silicone sealants. Furthermore, the amount of outgassing transferred from the photopolymerization initiator to the protective film can be reduced, and the post-reflow firing process can be omitted to increase reflectivity, thereby addressing power consumption issues. Furthermore, HAST resistance and reflectivity after HAST testing are high, and reflectivity degradation under high temperature / high humidity conditions can be suppressed. These characteristics of the photosensitive resin compositions disclosed herein enable the resulting solder resist to exhibit excellent results.

[0050] For example, the photosensitive resin composition according to one aspect of the present disclosure can achieve excellent reflectivity retention by further including titanium oxide as an inorganic filler.

[0051] According to the present disclosure, in some embodiments, a dry film, a cured product, a printed circuit board, and a laminated board all using the photosensitive resin composition may also be provided. Simple diagram description

[0052] [FIGS. 1a and 1b] are images showing BHAST test results of dry films using the photosensitive resin compositions of Comparative Example 1 and Example 3, respectively. Implementation Method

[0053] Various aspects of the present disclosure will be described below.

[0054] [Photosensitive resin composition]

[0055] One aspect of the present disclosure relates to a photosensitive resin composition comprising: (A) a carboxyl-containing resin free of aromatic rings; (B) an inorganic filler; and (E) a photopolymerization initiator selected from compounds containing a trimethylbenzylphosphine oxide group and having at least one PO bond.

[0056] Another aspect of the present disclosure relates to a photosensitive resin composition comprising: (A) a carboxyl-containing resin without an aromatic ring; (C) a mercapto-modified (meth)acrylate; and (E) a photopolymerization initiator selected from compounds containing a trimethylbenzylphosphine oxide group and having at least one PO bond.

[0057] The photosensitive resin composition can suppress degassing and exhibit excellent silicone sealant reaction rate, reflectivity and HAST resistance.

[0058] For example, the photosensitive resin composition may be a composition that is cured to form a solder resist.

[0059] Next, each component of the photosensitive resin composition is described in detail.

[0060] [(A) Carboxyl-containing resin not containing an aromatic ring]

[0061] In the photosensitive resin composition according to one embodiment of the present disclosure, the carboxyl-containing resin (A) not containing an aromatic ring (hereinafter referred to as "resin (A)") may be a resin that is cured by irradiation with active energy rays to exhibit electrical insulation. Examples of aromatic rings include a benzene ring, a pyridine ring, a pyrimidine ring, a triazine ring, and the like.

[0062] Resin (A) can be alkaline developed due to its carboxyl group content, and due to its lack of aromatic rings, it exhibits excellent resistance to discoloration and yellowing when exposed to heat or UV energy. Furthermore, combining resin (A) with inorganic filler (B) results in high reflectivity, minimal reflectivity drop after the reflow process, and minimal reflectivity drop after 3000 hours of blue light exposure. Therefore, compared to other white ink compositions, compositions containing resin (A) exhibit minimal reflectivity drop due to discoloration and yellowing and excellent resistance to yellowing. For example, compared to resin (A) without aromatic rings, carboxyl group-containing resins containing aromatic rings may exhibit relatively low initial reflectivity in their cured products, and their reflectivity significantly decreases when subjected to heat, UV, BHAST, and 85°C / 85% tests. This is because aromatic rings deform during heat, UV, BHAST, and 85°C / 85% tests, significantly reducing reflectivity.

[0063] For example, the resin (A) may have unsaturated double bonds. The resin (A) can be free radical-cured by ultraviolet light, electron beams, or heat due to the presence of saturated double bonds therein.

[0064] The resin (A) is not particularly limited as long as it contains a carboxyl group but does not contain an aromatic ring. Examples thereof include photosensitive carboxyl group-containing resins having at least one photosensitive unsaturated double bond or carboxyl group-containing resins having no photosensitive unsaturated double bond.

[0065] For example, a resin (any oligomer or polymer) not containing an aromatic ring from any of the following resins can be suitably used: (1) Carboxyl-containing resins obtained by copolymerization of unsaturated carboxylic acids and compounds having unsaturated double bonds; (2) a photosensitive carboxyl-containing resin obtained by reacting a carboxyl-containing (meth) acrylic copolymer resin with a compound having an ethylene oxide ring and an ethylenically unsaturated group in one molecule; (3) A photosensitive carboxyl group-containing resin obtained by reacting a copolymer of an unsaturated monocarboxylic acid with a compound having an unsaturated double bond and a compound having one unsaturated double bond and one epoxy group per molecule, and reacting a saturated or unsaturated polybasic acid anhydride with a secondary hydroxy group produced by the reaction; and (4) Resins containing photosensitive hydroxyl and carboxyl groups, obtained by reacting a hydroxyl-containing polymer with a saturated or unsaturated polybasic acid anhydride and then reacting the resulting compound having an epoxy group and an unsaturated double bond in one carboxylic acid molecule.

[0066] For example, the resin (A) may be a copolymer resin having a carboxyl group, which is obtained by reacting (a) a carboxyl group-containing (meth)acrylic copolymer resin as the photosensitive carboxyl group-containing resin (2) with (b) a compound having an ethylene oxide ring and an ethylenically unsaturated group in one molecule.

[0067] For example, the carboxyl group-containing (meth)acrylic copolymer resin (a) can be obtained by copolymerizing (meth)acrylate with a compound having one unsaturated group and at least one carboxyl group in one molecule, but is not limited thereto. Examples of the (meth)acrylates constituting the copolymer resin (a) include: alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, and hexyl (meth)acrylate; (meth)acrylates containing a hydroxyl group such as 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, and caprolactone-modified 2-hydroxyethyl (meth)acrylate; and ethylene glycol-modified (meth)acrylates such as methoxydiglycol (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, isooctyloxyethylene glycol (meth)acrylate, phenoxytriethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, and methoxypolyethylene glycol (meth)acrylate. These may be used alone or in combination of two or more. Here, (meth)acrylate is a general term for acrylate and methacrylate, and the same applies to other similar expressions.

[0068] Examples of compounds containing one unsaturated group and at least one carboxyl group in one molecule include acrylic acid, methacrylic acid; modified unsaturated monocarboxylic acids with a chain extending between the unsaturated group and the carboxylic acid, such as β-carboxyethyl (meth)acrylate, 2-acryloyloxyethyl succinic acid, 2-acryloyloxyethyl hexahydrophthalic acid, and unsaturated monocarboxylic acids with ester bonds formed through lactone modification; modified unsaturated monocarboxylic acids with ether bonds; and compounds containing two or more carboxyl groups in one molecule, such as maleic acid. These can be used alone or in combination of two or more.

[0069] The compound (b) having an ethylene oxide ring and an ethylenically unsaturated group in one molecule can be any compound having both an ethylene oxide ring and an ethylene oxide ring in one molecule. Examples thereof include glycidyl (meth)acrylate, α-methylglycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, 3,4-epoxycyclohexylethyl (meth)acrylate, 3,4-epoxycyclohexylbutyl (meth)acrylate, and 3,4-epoxycyclohexylmethylaminoacrylate. These compounds can be used alone or in combination of two or more. For example, the compound (b) having an ethylene oxide ring and an ethylenically unsaturated group in one molecule can be 3,4-epoxycyclohexylmethyl (meth)acrylate.

[0070] For example, the resin (A) may have an acid value of 30 mgKOH / g to 200 mgKOH / g. When the acid value of the resin (A) is 30 mgKOH / g or higher, the unexposed portion of the solder resist composition coating can be easily removed in a weakly alkaline aqueous solution. When the acid value of the resin (A) is 200 mgKOH / g or lower, the water resistance and electrical properties of the cured film can be improved.

[0071] For example, the weight average molecular weight of resin (A) can be 5,000 g / mol to 100,000 g / mol. When the weight average molecular weight of resin (A) is 5,000 g / mol or higher, deterioration in the dry feel of the solder resist composition coating film can be suppressed. When the weight average molecular weight of resin (A) is 100,000 g / mol or lower, deterioration in the developability and storage stability of the solder resist composition can be suppressed.

[0072] The content of resin (A) in the photosensitive resin composition of the present disclosure may be 5 wt% to 40 wt%, 10 wt% to 35 wt%, or 12 wt% to 33 wt%, relative to the total weight of the resin composition. The composition includes solids and a solvent. The content of resin (A) can be calculated based on the solid content.

[0073] When the content of the resin (A) is within the above range, excellent yellowing resistance and high reflectivity can be obtained, and a solder resist coating film can be formed favorably, excellent pencil hardness and adhesion can be exhibited, and the dry touch of the coating film and the reduction of undercut can be suppressed.

[0074] [(B) Inorganic filler]

[0075] The photosensitive resin composition according to one aspect of the present disclosure may obtain high reflectivity by including an inorganic filler.

[0076] Examples of inorganic fillers include titanium oxide, zinc oxide, basic carbonates, basic sulfates, sulfates, zinc sulfide, antimony oxide, aluminum hydroxide, silicon dioxide, barium sulfate, and the like. For example, when a composition is prepared using a mixture of barium sulfate and silicon dioxide as an inorganic filler, the L value is 80 or greater, the a value is -5 or greater, and the b value is -5 or greater. The L value can be measured using Hunter 1948. For example, when a composition is prepared using a high-content mixture of titanium oxide and silicon dioxide as an inorganic filler, the cured product of the composition has an L value of 90 or greater, an a value of -3 or greater, and a b value of -3 or greater, exhibiting high whiteness and reflectivity. For example, when a composition is prepared using at least one of titanium oxide or silicon dioxide as an inorganic filler, the highest whiteness and reflectivity are exhibited when the L value is 95 or greater, the a value is -2 or greater, and the b value is -1 or greater.

[0077] For example, the method for preparing titanium oxide can be either a sulfuric acid method or a chlorine method, with the chlorine method being preferred. For example, sulfuric acid may not be used in the preparation process. The surface treatment of titanium oxide is not particularly limited, but during the neutralization process, the titanium oxide may be treated with hydrochloric acid, nitric acid, phosphoric acid, acetic acid, or the like instead of sulfuric acid.

[0078] The titanium oxide may be any titanium oxide having any of the following structures: rutile, anatase, and ramsdellite. These may be used alone or in combination of two or more. Ramsdellite-type titanium oxide can be obtained by subjecting ramsdellite-type Li₁₀TiO₂ to a chemical lithium oxide desorption treatment.

[0079] Among these, the use of rutile titanium oxide can further enhance heat resistance, minimize discoloration caused by light exposure, and prevent quality degradation even in harsh usage environments. In particular, heat resistance can be improved by using rutile titanium oxide that has been surface-treated with aluminum oxide, such as alumina. The content of rutile titanium oxide surface-treated with aluminum oxide in the total titanium oxide can be, for example, 35% by mass or greater, for example 55% or greater, with an upper limit of 100% or less. In other words, the entire titanium oxide can be rutile titanium oxide surface-treated with aluminum oxide. Furthermore, anatase titanium oxide has a lower hardness than rutile titanium oxide, making it preferable for the moldability of the composition.

[0080] In the photosensitive resin composition of the present disclosure, the amount of the inorganic filler (B) mixed can be within a range of 30% to 70% by mass, for example, 40% to 70% by mass, or 45% to 70% by mass, relative to the total resin composition. The content of the inorganic filler (B) can be calculated based on the solid content. A content of the inorganic filler (B) within the above range contributes to high reflectivity, while a content below the above range results in reduced reflectivity, and a content exceeding the above range can cause cracking.

[0081] In the inorganic filler (B), the titanium oxide has a sulfur concentration of 100 ppm or less, or 50 ppm or less. Alternatively, commercially available titanium oxide with a sulfur concentration of 100 ppm or less may be used, or commercially available titanium oxide with a sulfur concentration of 100 ppm or more may be subjected to heat treatment, chemical treatment, or refining by washing, firing, or the like to reduce the sulfur concentration before mixing. Specifically, the sulfur contained in the titanium oxide refers to all sulfur detected by analysis. This sulfur includes sulfur adsorbed on the titanium oxide and sulfur incorporated as an impurity. Furthermore, the titanium oxide may have a sodium concentration of 100 ppm or less, or 50 ppm or less. A lower sodium concentration may be preferable. Excessively high sodium concentrations may accelerate corrosion or oxidation of the copper substrate when exposed to moisture caused by sodium ions. For this reason, the sodium ion concentration may be 100 ppm or less.

[0082] In addition, the photosensitive resin composition of the present disclosure may include titanium oxide having a sulfur concentration of 100 ppm or more, as long as the advantages of the present disclosure are not impaired. Examples of titanium oxide having a sulfur concentration of 100 ppm or more include CR-58, CR-90, and R-630 manufactured by ISHIHARA Co., Ltd., and R-21 manufactured by Sakai-Chem Co., Ltd.

[0083] Alternatively, T-550, T-580, R-630, R-820, CR-50, CR-60, R-90, or CR-97 manufactured by ISHIHARA SANGYO Co., Ltd., Ti PURE R-706, R-902+, or R931 manufactured by DuPont Co., Ltd., TR-600, TR-700, or TR-840 manufactured by Fuji Titanium Industries Co., Ltd., or KR-270, KR-310, and KR-380 manufactured by Titanium Industries Co., Ltd., which are rutile type chloride-based titanium oxides, may be used.

[0084] When the titanium oxide particle size is too small, fluidity may be impaired, while when the particle size is too large, the ability to be inserted into small-diameter substrates may be impaired. Taking this into account, the titanium oxide median particle size can be within the range of 0.1 μm to 5 μm, for example, within the range of 0.1 μm to 1 μm, for example, within the range of 0.1 μm to 0.5 μm, and can be 0.36 μm. When the titanium oxide particle size is within this range, high reflectivity can be exhibited. The above particle size is measured using laser diffraction.

[0085] Among the inorganic fillers (B), examples of barium sulfate may include precipitated barium sulfate #100, precipitated barium sulfate #300, precipitated barium sulfate SS-50, BARIACE B-30, BARIACE B-31, BARIACE B-32, BARIACE B-33, BARIACE B-34, BARIFINE BF-1, BARIFINE BF-10, BARIFINE BF-20, BARIFINE BF-40 (Sakai Chemical Industry Co., Ltd.), W-1, W-6, W-10, C300 (Takehara Kagaku Kogyo Co., Ltd.), and the like.

[0086] Among the inorganic fillers (B), silica particles are not particularly limited and can be obtained by methods known to those skilled in the art. For example, silica particles can be produced by burning silicon powder using the vaporized metal combustion (VMC) method. The VMC method forms a chemical salt using a burner in an oxygen-containing atmosphere. A metal powder, which constitutes a portion of the target oxide particles, is injected into the chemical salt in an amount sufficient to form a dust cloud, and detonation is induced to produce the oxide particles. Examples of commercially available silica include the SO series manufactured by Admatechs and the HPS series (HPS-0500, HPS-1000, HPS3500, etc.) manufactured by Toagosei.

[0087] [(C) Mercapto-modified (meth)acrylate]

[0088] The photosensitive resin composition according to one aspect of the present disclosure ensures enhanced surface curing by using a mercapto-modified acrylate (C), thereby achieving improved gloss and high reflectivity.

[0089] In addition, using the mercapto-modified acrylate (C) disclosed herein together with the inorganic filler (B) in the photosensitive resin composition can enhance the surface curing of the photosensitive resin layer, thereby achieving higher reflectivity and higher gloss through the enhanced surface curing.

[0090] The mercapto-modified acrylate (C) disclosed herein is a compound modified by introducing a mercapto group into an acrylate compound. The acrylate compound can be a monofunctional or polyfunctional acrylate compound; or an aliphatic compound having 1 to 15 carbon atoms substituted with at least one functional group selected from acryl, acryloxy, and acryloxyalkyl; or can be, for example, pentanetriacrylate.

[0091] The mercapto-modified acrylate (C) disclosed herein may be curable or active energy ray-curable. The mercapto-modified (meth)acrylate (C) disclosed herein can be obtained through a Michael addition reaction of a polyfunctional thiol compound and a stoichiometric excess of a difunctional or polyfunctional (meth)acrylate compound. Examples of the polyfunctional thiol compound include polyfunctional thiol compounds in reaction products of polyisocyanates, such as pentaerythritol tetrakis(3-mercaptopropionate) (molecular weight: 489 g / mol), trimethylolpropane tris(3-mercaptopropionate) (molecular weight: 399 g / mol), or 1,3-bis(2-isocyanato-2-propyl)benzene tetrakis(1,3-bis(2-isocyanato-2-propyl) benzenetetrathiol), and polyfunctional thiol compounds such as trimethylolpropane tris(3-mercaptopropionate); polyfunctional thiol compounds in reaction products of polyisocyanates, such as isophorone diisocyanate, and polyfunctional thiol compounds such as trimethylolpropane tris(3-mercaptopropionate); polyfunctional thiol compounds in reaction products of polyisocyanates, such as hexamethylene diisocyanate, and polyfunctional thiol compounds such as trimethylolpropane tris(3-mercaptopropionate); 1,6-hexanedithiol (molecular weight: 150 g / mol), ethylene glycol di-2-mercaptoacetate (molecular weight: 210 g / mol), pentaerythritol tetrakis(2-mercaptoacetate) (molecular weight: 433 g / mol) and trimethylolpropane tris(2-mercaptoacetate), ethylene glycol bis(3-mercaptopropionate) (molecular weight: 238 g / mol), etc. For example, the mercapto-modified acrylate (C) may have two or more mercapto groups or three or more mercapto groups.

[0092] The weight-average molecular weight of the mercapto-modified acrylate (C) can be 5000 g / mol or less, 3000 g / mol or less, or 2000 g / mol or less. At a weight-average molecular weight of 5000 g / mol or less, the mobility of the mercapto-modified (meth)acrylate molecules decreases, thereby suppressing the deterioration of the reactivity of the active energy ray-curable coating film formed by the present disclosure. For example, when the coating film is cured using UV-LEDs with deteriorated reactivity, the tackiness of the cured coating film surface increases, and when printed material is placed on the cured coating film, the cured coating film is likely to adhere to the printed material.

[0093] In the photosensitive resin composition of the present disclosure, the content of the mercapto-modified (meth)acrylate may be 1-20 parts by weight, 1-10 parts by weight, or 1-7 parts by weight, relative to a total of 100 parts by weight of the composition.

[0094] When the content of the mercapto-modified acrylate (C) is within the above range, enhanced surface curing, improved gloss, and high reflectivity can be achieved. Furthermore, even after the manufacturing process, minimal reflectivity reduction and excellent crack resistance can be achieved. Furthermore, gloss degradation caused by deterioration of surface curing can be suppressed, achieving high reflectivity. Appropriate surface curing can reduce coating damage and improve resolution.

[0095] [(D) Resin containing aromatic ring]

[0096] The photosensitive resin composition of the present disclosure may include a carboxyl-containing resin (A) having no aromatic ring, and may further include a resin (D) having an aromatic ring in addition to the resin (A).

[0097] The aromatic ring-containing resin (D) can exhibit excellent anti-yellowing properties by combining with the resin (A). The photosensitive resin composition according to one aspect of the present disclosure can exhibit excellent anti-yellowing properties by including the aromatic ring-containing resin (D) in a smaller content than that of the resin (A).

[0098] The aromatic ring-containing resin (D) of the present disclosure can be cured by, for example, heating to exhibit electrical insulation properties.

[0099] Examples of aromatic rings include benzene rings, pyridine rings, pyrimidine rings, triazine rings, and the like. Examples of the aromatic ring-containing resin (D) of the present disclosure may include melamine resins, silicone resins, and resins having a styrene backbone. For example, a resin having a styrene backbone may be used.

[0100] The aromatic ring-containing resin (D) may contain a carboxyl group and may be, for example, a carboxyl resin having a styrene backbone. For example, the aromatic ring-containing resin (D) may be a mixture of a carboxyl resin having a styrene backbone and a carboxyl resin other than the carboxyl resin having a styrene backbone.

[0101] For example, when the aromatic ring-containing resin (D) is a carboxyl-containing resin with a styrene backbone, this resin does not have a photosensitive group, such as an ethylenically unsaturated bond with a carboxyl group, but rather has a styrene backbone, an average molecular weight of 10,000 to 50,000 g / mol, and an acid value of 80 to 200 mgKOH / g. This carboxyl-containing resin with a styrene backbone can be synthesized by copolymerization using styrene as an essential monomer. By utilizing a carboxyl-containing resin with the aforementioned performance range, a cured coating film comprising the photosensitive resin composition of the present disclosure exhibits an excellent dry feel and anti-flow effect.

[0102] The carboxyl resin having a styrene backbone may be, for example, a carboxyl resin (either an oligomer or a polymer) obtained by copolymerizing an unsaturated carboxylic acid such as (meth)acrylic acid with a compound containing an unsaturated group selected from styrene, α-methylstyrene, a lower alkyl (meth)acrylate, isobutylene, and the like. Specifically, the lower alkyl group may refer to an alkyl group having 1 to 5 carbon atoms.

[0103] In the photosensitive resin composition of the present disclosure, the weight-average molecular weight of the carboxyl-containing resin having a styrene backbone varies depending on the backbone of the resin, but can be 10,000 g / mol to 50,000 g / mol, 10,000 g / mol to 25,000 g / mol, 10,000 g / mol to 20,000 g / mol, or 10,000 g / mol to 17,000 g / mol. A weight-average molecular weight of 10,000 g / mol or greater can improve anti-flow properties and dry touch (stickiness), enhance moisture resistance of the exposed coating, suppress film thinning during development, and inhibit resolution degradation. Furthermore, a weight-average molecular weight of 50,000 g / mol or less can improve anti-flow properties, developability, and storage stability.

[0104] In the photosensitive resin composition of the present disclosure, the acid value of the carboxyl resin can be 80 mgKOH / g to 200 mgKOH / g, or 100 mgKOH / g to 180 mgKOH / g. When the acid value of the carboxyl resin having a styrene backbone is 80 mgKOH / g or higher, the softening point can be increased, thereby improving adhesion and developability. When the acid value of the carboxyl resin having a styrene backbone is 200 mgKOH / g or lower, stress is not generated during the curing process due to the appropriate crosslinking density, and a good coating film can be obtained.

[0105] In the photosensitive resin composition of the present disclosure, the carboxyl-containing resin having a styrene backbone, despite having aromatic rings, can suppress discoloration and reduction in reflectivity of the cured product under light irradiation or heating due to the styrene backbone, and exhibits excellent developability and dry touch. The proportion of the styrene backbone in the molecule can be 10 mol% to 80 mol%, 10 mol% to 60 mol%, or 10 mol% to 50 mol%. That is, when synthesizing the carboxyl-containing resin having a styrene backbone, 30 mol% to 60 mol% of styrene can be used relative to the total amount of monomers. When the proportion of the styrene backbone of the carboxyl-containing resin in the molecule is 10 mol% or higher, improved compatibility with other components can be achieved, and when this proportion is 80 mol% or lower in the molecule, good developability can be achieved.

[0106] Carboxyl-containing resins with a styrene backbone can be prepared through suspension polymerization to achieve high molecular weights. Consequently, photosensitive resin compositions using these resins can exhibit excellent dry touch (tacky) properties. Generally, carboxyl-containing resins with a styrene backbone exhibit high molecular weights when prepared through suspension polymerization. However, considering properties such as screen printing compatibility, dry touch, and developability, the weight-average molecular weight of the resin is limited to a range of 10,000 to 50,000 g / mol. Therefore, to control the molecular weight, chain transfer agents may be used in the synthesis of carboxyl-containing resins with a styrene backbone.

[0107] Furthermore, to accelerate polymerization, a polymerization initiator can be used in the synthesis of a carboxyl-containing resin with a styrene backbone. Examples of polymerization initiators include benzoyl peroxide (BPO), tertiary butyl peroxy-2-ethylhexanoate, and 2,2'-azobis(2-methylbutyronitrile) (AMBN). A polymerization inhibitor can be benzoyl peroxide (BPO). The amount of the polymerization initiator mixed, based on solid content, can be 0.1 to 10 wt% or 0.1 to 6 wt% relative to 100 wt% of the carboxyl-containing resin with a styrene backbone.

[0108] In the photosensitive resin composition of the present disclosure, the content of the aromatic ring-containing resin (D) may be 0.1 wt % to 15 wt %, 1 wt % to 10 wt %, or 2 wt % to 6 wt % relative to the total weight of the composition. The photosensitive resin composition includes a solid and a solvent.

[0109] When the content of the aromatic ring-containing resin (D) is within the above range, discoloration and reduction in reflectivity are suppressed, and developability and dry touch are excellent, whereby the effects of improving reflectivity and preventing yellowing can be further enhanced.

[0110] [(E) Photopolymerization initiator]

[0111] The photosensitive resin composition according to one aspect of the present disclosure may include a photopolymerization initiator (E) of a compound including a trimethylbenzylphosphine oxide group having at least one PO bond (hereinafter referred to as “photopolymerization initiator (E)”).

[0112] 2,4,6-trimethylbenzoyldiphenylphosphine oxide (TPO), a widely used conventional photopolymerization initiator, produces a large amount of outgassing during the curing process. This outgassing diffuses into the silicone sealant layer or protective film, causing the silicone sealant to yellow, reducing reflectivity and hindering curing. This poses a problem for the long-term reliability of these products.

[0113] The polymer containing trimethylbenzylphosphine oxide groups as a photopolymerization initiator has a high molecular weight and a high molecular weight, so the amount of outgassing due to heat is small even in the final curing step, reflow and sintering processes using heat.

[0114] Meanwhile, even compounds containing trimethylbenzylphosphine oxide, which has a lower molecular weight than TPO, contain one or more PO bonds, resulting in enhanced intermolecular bonding (e.g., forming stronger hydrogen bonds with the remaining OH or COOH groups in the composition without reacting), thereby significantly suppressing outgassing of the photopolymerization initiator.

[0115] For example, a compound containing a trimethylbenzylphosphine oxide group may include three or more hydrogen-bondable sites. This can enhance the intermolecular bonding force, thereby significantly suppressing the outgassing of the photopolymerization initiator.

[0116] Therefore, this can solve the yellowing and non-curing problems of silicone sealants, reduce the outgassing amount of photopolymerization initiator transferred to the protective film, and significantly increase the reaction rate of silicone sealants.

[0117] When using a photopolymerization initiator such as TPO, a separate firing step (for example, curing at 150°C for 6 hours) is added after the reflow process to effectively remove the generated outgassing, but this firing step results in a significant decrease in reflectivity, leading to increased power consumption when mounting the wafer.

[0118] However, the use of the above-mentioned photopolymerization initiator (E) disclosed herein can omit the firing process, reducing working time, thereby increasing productivity and reducing costs, improving reflectivity, and preventing power consumption caused by reduced reflectivity. Even without a protective film for removing the photopolymerization initiator, it can minimize outgassing of the photopolymerization initiator, significantly improve the degree of silicone curing, enhance long-term reliability, and exhibit excellent HAST resistance and reflectivity after HAST testing. Furthermore, it can suppress the reduction of reflectivity under high temperature and high humidity conditions.

[0119] The photopolymerization initiator (E) may be liquid at room temperature (20° C.) and 1 atmosphere.

[0120] The photopolymerization initiator (E) may have a PO bond.

[0121] The photopolymerization initiator (E) may include a *-C(=O)-P(=O)R1-O-*' portion (wherein R1 is an alkyl group of 1 to 20 carbon atoms, an alkenyl group of 2 to 20 carbon atoms, an alkynyl group of 2 to 20 carbon atoms, or a cyclic group of 5 to 20 carbon atoms)

[0122] When the photopolymerization initiator (E) is a polymer containing a trimethylbenzylphosphine oxide group, the weight average molecular weight (Mn) of the polymer containing a trimethylbenzylphosphine oxide group may be about 1,000 g / mol or greater. For example, the weight average molecular weight (Mn) of the polymer containing a trimethylbenzylphosphine oxide group may be 1,000 g / mol to 100,000 g / mol.

[0123] The polymer containing a trimethylbenzylphosphine oxide group may be represented by the following Chemical Formula 1.

[0124] <Chemical Formula 1>

[0125] a = 0 to 100, b = 0 to 100, and c = 0 to 100.

[0126] When the photopolymerization initiator (E) is a trimethylbenzylphosphine oxide group-containing compound having a PO bond, the trimethylbenzylphosphine oxide group-containing compound having a PO bond may include an alkoxy group.

[0127] For example, a+b+c>0 in chemical formula 1.

[0128] For example, the trimethylbenzylphosphine oxide group-containing compound having a PO bond may include an ethoxy group.

[0129] The trimethylbenzylphosphine oxide group-containing polymer having a PO bond may be represented by the following Chemical Formula 2.

[0130] <Chemical Formula 2>

[0131] For example, the photopolymerization initiator (E) may further include at least one selected from benzoin and its alkyl ethers, acetophenone, anthraquinone, thioxanthone, ketal, benzophenone, α-aminoacetophenone, acylphosphine oxide, acylphosphinate, and oxime ester.

[0132] In the photosensitive resin composition of the present disclosure, the content of the photopolymerization initiator (E) may be 0.01 wt% to 10 wt%, 0.01 wt% to 7 wt%, or 0.01 wt% to 5 wt% relative to the total composition. The photopolymerization initiator (E) contained within the above ranges produces sufficient photocurability on copper, resulting in good coating film curability, improved coating film properties such as chemical resistance, and improved deep curing properties.

[0133] The content of the photopolymerization initiator (E) within the above range results in a gentle undercut and inconspicuous expansion (halation) of the upper portion, resulting in excellent resolution and a large number of solder resist openings. In addition, high reflectivity can be maintained.

[0134] [(F) Silane coupling agent]

[0135] The photosensitive resin composition according to one aspect of the present disclosure may further include a silane coupling agent (F). By including the silane coupling agent (F), the photosensitive resin composition may exhibit improved crack resistance, increased reflectivity compared to existing ones, and excellent gloss.

[0136] The silane coupling agent (F) of the present disclosure may have an organic group, such as a vinyl group, a styryl group, an acryl group, a methacryl group, an acid anhydride group, an urea group, an epoxy group, an amino group, a methacryloyloxy group, a mercapto group, an isocyanate group, or an isocyanurate group.

[0137] Examples of silane coupling agents having a vinyl group may include vinyltrimethoxysilane, vinyltriethoxysilane, and the like. Examples of silane coupling agents having a styrene group may include p-styrenemethoxysilane, and the like. Examples of silane coupling agents having a methacrylic group may include 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyldiethoxysilane, and 3-methacryloxypropyltriethoxysilane, and the like. Examples of silane coupling agents having an acrylic group may include 3-acryloxypropyltrimethoxysilane, and the like. Examples of silane coupling agents having an amino group may include N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxy-silyl-N-(1,3-dimethyl-butylene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane, etc. Examples of silane coupling agents having a methacryloxy group may include 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, etc. Examples of silane coupling agents having a mercapto group may include 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, and the like. Examples of silane coupling agents having an isocyanate group may include 3-isocyanatepropyltriethoxysilane, and the like. Examples of silane coupling agents having an isocyanurate group may include tris-(trimethoxysilylpropyl)isocyanurate. Examples of silane coupling agents having a urea group may include 3-ureidopropyltrialkoxysilane, and the like. Examples of silane coupling agents having an anhydride group may include 3-(trimethoxysilyl)propylsuccinic anhydride, and the like.

[0138] The silane coupling agent may be a silane coupling agent having an epoxy group, and examples thereof may include 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethylbisethoxysilane, and 3-glycidoxypropyltriethoxysilane.

[0139] In the photosensitive resin composition of the present disclosure, the content of the silane coupling agent (F) may be 0.1 wt % to 5 wt %, 0.3 wt % to 3 wt %, or 0.4 wt % to 2 wt % relative to the total composition. The composition includes a solid and a solvent.

[0140] When the content of the silane coupling agent (E) is within the above range, the composition has excellent crack resistance, high reflectivity, excellent adhesion, and low viscosity, and thus can be suitable for film formation.

[0141] The silane coupling agent (F) may be a commercially available product, and examples thereof may include KBM-1003, KBE-1003, KBM-303, KBM-402, KBM-403, KBE-402, KBE-403, KBM-1403, KBM-502, KBM-503, KBE-502, KBE-503, KBM5103, KBM-602, KBM-603, KBM-903, KBE-903, KBE-9103P, KBM-573, KBM-575, KBM-9659, KBM-585A, KBM-802, KBM-803, KBE-0007N, X-12-967C, and the like, all of Shin-Etsu Kagaku Kogyo.

[0142] [(G) Resin having a urethane bond]

[0143] The photosensitive resin composition according to one aspect of the present disclosure may further include a resin (G) having a urethane bond. The resin (G) having a urethane bond may have excellent flexibility.

[0144] By using the resin (G) having a urethane bond, the photosensitive resin composition does not break even on a flexible substrate or a thin plate having a small thickness, allows lamination to a uniform thickness, and has excellent crack resistance or fracture resistance when subjected to external impact or bending.

[0145] The resin (G) having a urethane bond of the present disclosure may include a modified urethane resin, and examples of the resin having a urethane bond may include ester-type urethane, ether-type urethane, modified urethane acrylate, modified urethane epoxy resin, silicone-modified urethane, or fluorine-type modified urethane, and may be, for example, a modified urethane epoxy acrylate containing an epoxy group.

[0146] The resin (G) having a urethane bond of the present disclosure can use a conventional compound having a urethane bond. Examples thereof include reaction products of isocyanate compounds (e.g., monoisocyanates, diisocyanates, and polyisocyanates) with compounds having an OH group (e.g., monohydric alcohols, polyols such as polyester polyols or polyether polyols, and epoxy (meth)acrylates), or modified products thereof.

[0147] The resin (G) having a urethane bond of the present disclosure may have a carboxyl group, an epoxy group, or a (meth)acrylic group, and examples thereof may include (1) carboxyl group-containing resins, (2) epoxy group-containing resins, (3) urethane resins, (4) photosensitive polyurethane resins, (5) (meth)acrylic group-containing resins, etc.: (1) Carboxyl-containing photosensitive polyurethane resins obtained by the polyaddition reaction of a carboxyl-containing diol compound, a diol compound and a diisocyanate with a reaction product of a monocarboxylic acid compound having an ethylenically unsaturated double bond, for example, difunctional epoxy resin (meth)acrylates such as bisphenol A epoxy resin, hydrogenated bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, bixylenol epoxy resin or novolac epoxy resin, partial anhydrides thereof or modifications thereof; (2) Urethane-modified epoxy resins having a urethane bond and two or more epoxy moieties in the molecule, obtained by reacting a hydroxyl-containing epoxy compound with a urethane bond-containing compound having an isocyanate group obtained by reacting a polyhydroxy compound with a polyisocyanate compound; (3) Urethane resins obtained by polyaddition reaction of diisocyanates (e.g., aliphatic diisocyanates, branched diisocyanates, alicyclic diisocyanates or aromatic diisocyanates) and diol compounds (e.g., polycarbonate-based polyols, polyether-based polyols and polyester-based polyols, polyolefin polyols, acryl polyols, epoxy resins having hydroxyl groups (which can be used to obtain urethane resins having epoxy groups), bisphenol A alkylene oxide adduct diols, compounds having phenolic hydroxyl groups and alcoholic hydroxyl groups); (4) a photosensitive polyurethane resin obtained by a polyaddition reaction of an isocyanate and a diol compound, wherein part or all of the diisocyanate in (3) above is replaced by a reaction product of isophorone diisocyanate and pentaerythritol triacrylate and / or a compound having one isocyanate group and one or more (meth)acryloyl groups in the molecule; and (5) A terminal (meth)acrylated photosensitive polyurethane resin prepared by adding a compound having one hydroxyl group and one or more (meth)acrylic groups in the molecule, such as a hydroxyalkyl (meth)acrylate, during the synthesis of one of the resins (3) and (4).

[0148] Furthermore, as described above, one resin may have at least two types of carboxyl groups, epoxy groups, or methacryl groups.

[0149] The resin (G) having a urethane bond may be (1) in a carboxyl group-containing resin, (2) in an epoxy group-containing resin, and (5) in a (meth)acrylic group-containing resin.

[0150] The diisocyanate may be, for example, an aromatic polyisocyanate, an aliphatic polyisocyanate, or an alicyclic polyisocyanate. Examples of aromatic polyisocyanates include 4,4'-diphenylmethane diisocyanate, 2,4-diisocyanate-2,6-toluene diisocyanate, naphthalene-1,5-diisocyanate-o-xylene diisocyanate, m-xylene diisocyanate, 2,4-triene dimer, and the like. Examples of aliphatic polyisocyanates include tetramethylene diisocyanate, hexamethylene diisocyanate, methylene diisocyanate and trimethylhexamethylene diisocyanate, 4,4-methylenebis(cyclohexyl isocyanate), and isophorone diisocyanate. Examples of alicyclic polyisocyanates include dicycloheptane triisocyanate. For example, the diisocyanate may be an aliphatic isocyanate.

[0151] When the resin (G) having a urethane bond is a carboxyl group-containing resin having a urethane bond, the acid value of the carboxyl group-containing resin may be 40 mgKOH / G to 200 mgKOH / G or 45 mgKOH / G to 120 mgKOH / G. When the acid value of the carboxyl group-containing resin is within the range of 40 mgKOH / G to 200 mgKOH / G, adhesion of the cured film is ensured to facilitate alkali development, thereby suppressing dissolution of the exposed area by the developing solution, preventing the line from being narrowed more than necessary, thereby allowing easy drawing of a normal resist pattern.

[0152] When the resin (G) having a urethane bond is a carboxyl-containing resin having a urethane bond, the weight-average molecular weight of the carboxyl-containing resin varies depending on the main chain of the resin, but can be 2,000 g / mol to 150,000 g / mol, 5,000 g / mol to 50,000 g / mol, or 2,000 g / mol to 50,000 g / mol. A weight-average molecular weight of the carboxyl-containing resin within the above ranges results in good tack, thereby improving the moisture resistance of the cured film and reducing thinning of the coating film during development. Furthermore, a weight-average molecular weight within the above ranges can result in good resolution and developability, as well as improved storage stability.

[0153] Exemplary commercially available products of the resin (G) having a urethane bond (e.g., a carboxyl group-containing resin having a urethane bond) may include UXE-3000 (Japan Explorers Co., Ltd.), EPU-7N (urethane-modified epoxy resin; ADEKA Co., Ltd.), and Ebecryl 210 (aromatic urethane acrylate; Daicel Allnex Co., Ltd.).

[0154] In the photosensitive resin composition of the present disclosure, the content of the resin (G) having a urethane bond can be 0.1 wt% to 15 wt%, 5 wt% to 13 wt%, or 8 wt% to 12 wt% relative to the total composition. The composition includes solids and a solvent. When the content of the resin (G) having a urethane bond is within the above range, the composition can exhibit excellent flexibility and crack resistance, moderate adhesion, and excellent printability and drying properties.

[0155] In the photosensitive resin composition of the present disclosure, the weight average molecular weight of the resin (G) having a urethane bond may be 2,000 g / mol to 150,000 g / mol or 2,000 g / mol to 50,000 g / mol. When the weight average molecular weight of the resin (G) having a urethane bond is within the above range, the composition may exhibit excellent crack resistance and flexibility.

[0156] [Other optional components]

[0157] If necessary, various additives may be added as optional components to the photosensitive resin composition of the present disclosure. Specifically, a thermal curing catalyst, a dispersant, an antioxidant, a colorant, an epoxy resin, an oxetane compound, a (meth)acrylic resin, and various other additives, or a mixture of two or more thereof, may be added. One or more of the following materials may be included as optional ingredients.

[0158] <Epoxy resin>

[0159] The epoxy resin disclosed herein can be a well-known and commonly used compound having one or more epoxy groups. For example, the epoxy resin may not overlap with the above components (A) to (G). For example, the epoxy resin may be a compound having two or more epoxy groups. Examples of epoxy resins include monoepoxy compounds such as butyl glycidyl ether, phenyl glycidyl ether, or glycidyl (meth)acrylate, as well as compounds having two or more epoxy groups per molecule, such as bisphenol A epoxy resin, bisphenol S epoxy resin, bisphenol F epoxy resin, phenol novolac epoxy resin, cresol novolac epoxy resin, alicyclic epoxy resin, trimethylolpropane polyglycidyl ether, phenyl-1,3-diglycidyl ether, biphenyl-4,4'-diglycidyl ether, 1,6-hexanediol diglycidyl ether, diglycidyl ether of ethylene glycol or propylene glycol, sorbitol polyglycidyl ether, tris(2,3-epoxypropyl)isocyanurate, or triglycidyl tris(2-hydroxyethyl)isocyanurate. These can be used alone or in combination of two or more, depending on the desired properties.

[0160] Examples of compounds having two or more epoxy groups include bisphenol A epoxy resins such as jER828, jER834, jER1001, and jER1004 from Mitsubishi Chemical Co., Ltd., EPICLON 840, EPICLON 850, EPICLON 1050, and EPICLON 2055 from DIC Co., Ltd., Epototo D-011, YD-013, YD127, and YD-128 from Nittetsu Chemical & Materials Co., Ltd., DER317, DER331, DER661, and DER664 from Dow Chemical Japan Co., Ltd., Sumi Epoxy ESA-011, ESA-014, ELA-115, and ELA128 from Sumitomo Chemical Co., Ltd., Asahi Kasei Materials Co., Ltd. AER330, AER331, AER661 and AER664 (all trade names); brominated epoxy resins such as Mitsubishi Chemical Co., Ltd. jERYL903, DIC Co., Ltd. EPICLON 152 and EPICLON 165, Nittetsu Chemical & Materials Co., Ltd. Epototo YDE-400 and YDE-500, Dow Chemical Japan Co., Ltd. DER542, Sumitomo Chemical Co., Ltd. Sumitoepoxy ESB-400 and ESB-700, Asahi Kasei Materials Co., Ltd. AER711 and AER714 (all trade names); novolac epoxy resins such as Mitsubishi Chemical Co., Ltd. jER152 and jER154, Dow Chemical Japan Co., Ltd. DEN431 and DEN438, EPICLON N-730, EPICLON N-770, and EPICLON N-865 from DIC Co., Ltd., Epototo YDC-701 and YDC-704 from Nittetsu Chemical & Materials Co., Ltd., EPPN-201, EPPN-1025, EPPN-1020, EPPN-104S, RE-306, and NC-3000 from Japan Chemical Co., Ltd., Sumi Epoxy ESCN-195X and ESCN-220 from Sumitomo Chemical Co., Ltd., AERECN-235 and ECN-299 from Asahi Kasei Materials Co., Ltd., Nittetsu Chemical & YDCN-700-2, YDCN-700-3, YDCN-700-5, YDCN-700-7, YDCN-700-10, YDCN-704, and YDCN-704A from DIC Materials Co., Ltd., EPICLON N-680, N-690, and N-695 (all trade names) from DIC Co., Ltd.; bisphenol F epoxy resins such as EPICLON 830 from DIC Co., Ltd., jER807 from Mitsumi Chemical Co., Ltd., Epototo YDF-175 and YDF-2004 (all trade names) from Nittetsu Chemical & Materials Co., Ltd.; hydrogenated bisphenol A epoxy resins such as Epototo ST-2004, ST-2007, and ST-3000 (all trade names) from Nittetsu Chemical & Materials Co., Ltd., jER 604, Ephotouto YH-434 from Nittetsu Chemical & Materials Co., Ltd.; glycidylamine-type epoxy resins, such as Sumi Epoxy ELM-120 (trade name) from Sumitomo Chemical Co., Ltd.; hydantoin epoxy resins; aliphatic epoxy resins, such as Celloxide 2021 (trade name) from Daicel Co., Ltd.; trihydroxyphenylmethane epoxy resins, such as YL-933 from Mitsubishi Chemical Co., Ltd. and TEN from Dow Chemical Japan Co., Ltd., EPPN-501 and EPPN-502 (all trade names); bis-xylenol or bisphenol epoxy resins, such as YL-6056, YX-4000 and YL-6121 of Mitsubishi Chemical Co., Ltd. or mixtures thereof (all trade names); bisphenol S epoxy resins, such as EBPS-200 of Kayaku Co., Ltd., EPX-30 of ADEKA and EXA-1514 of DIC Co., Ltd. (all trade names); bisphenol A novolac epoxy resins, such as jER 157S (trade name) of Mitsubishi Chemical Co., Ltd.; tetraphenylolethane epoxy resins, such as jER YL-931 (trade name) of Mitsubishi Chemical Co., Ltd.; heterocyclic epoxy resins, such as TEPIC (trade name) of Nissan Chemical Co., Ltd.; diglycidyl phthalate resins, such as Brenmer DGT; tetraglycylyl kylenoylethane resin, such as ZX-1063 from Nittetsu Chemical & Materials Co., Ltd.; naphthalene-containing epoxy resins, such as ESN-190 and ESN-360 from Nittetsu Chemical & Materials Co., Ltd., and HP-4032, EXA-4750, and EXA-4700 from DIC Co., Ltd.; epoxy resins having a dicyclopentadiene backbone, such as HP-7200 and HP-7200H from DIC Co., Ltd.; glycidyl methacrylate copolymer epoxy resins, such as CP-50S and CP-50M from Niche Oil Co., Ltd.; copolymer epoxy resins of cyclohexylmaleimide and glycidyl methacrylate; and CTBN-modified epoxy resins (such as YR-102 and YR-450 from Nittetsu Chemical & Materials Co., Ltd.), but are not limited thereto. Among them, the compound having two or more epoxy groups may be a bisphenol A epoxy resin, a heterocyclic epoxy resin, or a mixture thereof, rather than a resin having excellent anti-discoloration properties. These epoxy resins may be used alone or in combination of two or more.

[0161] In the photosensitive resin composition of the present disclosure, the epoxy resin may be a bisphenol-based epoxy resin, for example, a bisphenol-based epoxy resin having two or more epoxy groups. The blending amount of the bisphenol-based epoxy resin having two or more epoxy groups used in the present disclosure may be 1 wt% to 15 wt%, 1 wt% to 10 wt%, or 3 wt% to 10 wt% relative to the total composition. The composition includes a solid and a solvent.

[0162] When the content of the epoxy resin is within the above range, a coating film formed from the composition exhibits excellent adhesion, heat resistance, and pencil hardness, undergoes good curing, and can solve problems such as yellowing and difficulty in achieving high reflectivity after processing.

[0163] In the photosensitive resin composition of the present disclosure, the weight average molecular weight of the epoxy resin may be 150 g / mol to 100,000 g / mol.

[0164] <Oxetane Compounds>

[0165] Next, the oxetane compound will be described. The oxetane compound containing the oxetane ring is represented by the following general formula (I): (I)

[0166] (wherein R 1 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms). Specific examples of the oxetane compound may include 3-ethyl-3-hydroxymethyloxetane (DongA Synthetic Co., Ltd., trade name: OXT-101), 3-ethyl-3-(phenoxymethyl)oxetane (DongA Synthetic Co., Ltd., trade name: OXT-211), 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane (DongA Synthetic Co., Ltd., trade name: OXT-212), 1,4-bis{[(3-ethyl-3-oxetanyl)methoxy]methyl}benzene (DongA Synthetic Co., Ltd., trade name: OXT-121), and bis(3-ethyl-3-oxetanylmethyl)ether (DongA Synthetic Co., Ltd., trade name: OXT-221). In addition, examples thereof include phenol novolac type oxetane compounds. Such oxetane compounds can be used alone or in combination with epoxy compounds.

[0167] <(Meta)acrylic resin>

[0168] (Meth)acrylic resins are photocurable resins. The photocurable resin is not limited, as long as it cures upon exposure to active energy rays to exhibit electrical insulation properties. For example, it may be a compound having at least one ethylenically unsaturated bond in the molecule. For example, the (meth)acrylic resin may not overlap with the aforementioned components (A) to (G).

[0169] Compounds having ethylenically unsaturated bonds may include well-known and commonly used photopolymerizable oligomers, photopolymerizable monomers, and photopolymerizable vinyl monomers. The photopolymerizable oligomer may be an unsaturated polyester-based oligomer, a (meth)acrylate-based oligomer, or the like. Examples of (meth)acrylate-based oligomers may include epoxy (meth)acrylates, such as phenol novolac epoxy (meth)acrylate, cresol novolac epoxy (meth)acrylate, and bisphenol-type epoxy (meth)acrylates, urethane (meth)acrylates, epoxyurethane (meth)acrylates, polyester (meth)acrylates, polyether (meth)acrylates, and polybutadiene-modified (meth)acrylates.

[0170] As the photopolymerizable monomer or photopolymerizable vinyl monomer, well-known and commonly used monomers can be used, and examples thereof may include: styrene derivatives such as styrene, chlorostyrene, and α-methylstyrene; vinyl esters such as vinyl acetate, vinyl butyrate, and vinyl benzoate; ethers such as vinyl isobutyl ether, vinyl n-butyl ether, polyvinyl tertiary butyl ether, vinyl n-amyl ether, vinyl isopentyl ether, vinyl n-octadecyl ether, vinyl cyclohexyl ether, ethylene glycol monobutyl ether, and triethylene glycol monomethyl ether; (meth)acrylamides such as acrylamide, methylacrylamide, and methylvinyl ether; Enamides, N-methylol acrylamide, N-methylol methacrylamide, N-methoxy methacrylamide, N-ethoxy methacrylamide, and N-butoxy methacrylamide; aromatic compounds such as triallyl isocyanurate, diaryl phthalates, and diaryl isophthalates; (meth)acrylates such as 2-ethylhexyl (meth)acrylate, dodecyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, isoboroniae (meth)acrylate, (meth) Phenyl acrylate and phenoxyethyl (meth)acrylate; hydroxyalkyl (meth)acrylates such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate and pentaerythritol tri(meth)acrylate; alkoxyalkylene glycol mono(meth)acrylates such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate; alkylene polyol poly(meth)acrylates such as ethylene glycol di(meth)acrylate, butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, acrylates, such as tris[(meth)acryloyloxyethyl]isocyanurate; polyoxyalkylene glycol poly(meth)acrylates, such as diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, ethoxylated trimethylolpropane triacrylate, and propoxylated trimethylolpropane tri(meth)acrylate; poly(meth)acrylates, such as neopentyl glycol hydroxypivalate di(meth)acrylate; and isonalate-type poly(meth)acrylates, such as tris[(meth)acryloyloxyethyl]isocyanurate, which may be used alone or in combination of two or more.

[0171] In the photosensitive resin composition of the present disclosure, the (meth)acrylic resin can be an unsaturated polyester-based oligomer, a (meth)acrylate-based oligomer, or the like, and can be, for example, a hexafunctional flexible acrylic oligomer. The (meth)acrylic resin can be incorporated in an amount of 1 to 15 wt%, 1 to 10 wt%, or 5 to 10 wt% relative to the total composition. The composition includes solids and a solvent. When the (meth)acrylic resin content is within the above range, excellent resolution and undercut can be achieved, and the coating film can be cured to an appropriate level.

[0172] <Thermal Curing Catalyst>

[0173] In the composition of the present disclosure, at least one type of curing agent or curing catalyst may be further added as a thermal curing catalyst. For example, the thermal curing catalyst may not overlap with the above components (A) to (G).

[0174] Examples of curing agents include polyfunctional phenolic compounds, polycarboxylic acids and their anhydrides, aliphatic or aromatic primary or secondary amines, polyamide resins, isocyanate compounds, and polythiol compounds. The curing agent may be, for example, a polyfunctional phenolic compound, polycarboxylic acid, and its anhydride. The use of these curing agents can ensure good processability and insulation properties. The polyfunctional phenolic compound may be specifically limited as long as the compound has two or more phenolic hydroxyl groups in one molecule and may be, for example, a well-known and commonly used compound. Examples of polyfunctional phenolic compounds include phenol novolac resins, cresol novolac resins, bisphenol A, allyl bisphenol A, bisphenol F, bisphenol A novolac resins, and vinylphenol copolymer resins. The polyfunctional phenolic compound may be, for example, bisphenol A, and thus can ensure high reactivity and high heat resistance. The polyfunctional phenolic compound may undergo an addition reaction with at least one type of epoxy compound or octane compound in the presence of an appropriate curing catalyst. The polycarboxylic acid and its anhydride may be a compound having two or more carboxyl groups in one molecule and its anhydride, and may include, for example, a (meth)acrylic acid copolymer, a maleic anhydride copolymer, a dibasic acid condensation product, etc. Examples of commercially available products may include Joncryl (product group name) from BASF, SMA resin (product group name) from Sartomer, and polyazelaic polyanhydride from New Japan Chemical Co., Ltd.

[0175] A curing catalyst is a compound that can act as a curing catalyst in the reaction between a curing agent and a thermosetting resin, such as an epoxy compound or an oxetane compound, or a polymerization catalyst when no curing agent is used. Specific examples of curing catalysts include tertiary amines, tertiary amine salts, quaternary ammonium salts, tertiary phosphines, crown ether compounds, and phosphonium ylides, which can be used alone or in combination of two or more.

[0176] Examples of curing catalysts may include imidazoles, such as trade names 2E4MZ, C11Z, C17Z, and 2PZ; imidazole AZINE compounds, such as trade names 2MZ-A and 2E4MZ-A; isocyanurates of imidazoles, such as trade names 2MZ-OK and 2PZ-OK; imidazole hydroxymethyl compounds, such as trade names 2PHZ and 2P4MHZ (Shikoku Kasei Industrial Co., Ltd.); dicyandiamide and its derivatives; melamine and its derivatives; diaminomalononitrile and its derivatives; amines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, bis(hexamethylene)triamine, triethanolamine and diaminodiphenylmethane; 1,8-diazabicyclo[5,4,0]undecene-7 (trade name DBU, San-Apro Co., Ltd.); 3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro[5,5]undecane (trade name ATU, Ajinomoto Co., Ltd.); or organic phosphine compounds such as triphenylphosphine, tricyclohexylphosphine, tributylphosphine and methyldiphenylphosphine.

[0177] In the photosensitive resin composition of the present disclosure, the curing catalyst may be an amine-based, phosphine-based, or imidazole-based curing catalyst, and may be, for example, a melamine-based amine curing catalyst. The curing catalyst may be present in an amount of 0.1 wt% to 10 wt%, 0.1 wt% to 5 wt%, or 0.1 wt% to 3 wt% relative to the total composition.

[0178] When the content of the curing catalyst is within the above range, the coating film can be sufficiently cured to exhibit excellent adhesion, pencil hardness, and heat resistance, ensure an appropriate curing time, and prevent deterioration of developability.

[0179] <Antioxidants>

[0180] The photosensitive resin composition of the present disclosure may also include an antioxidant. The addition of an antioxidant can prevent oxidative degradation of the curable resin, thereby suppressing discoloration, while achieving enhanced heat resistance and good resolution (reproducibility of line width). In other words, white colorants can reduce resolution through reflection and absorption of light depending on their type, but regardless of the type of white colorant, the inclusion of an antioxidant can achieve good resolution. Antioxidants can be free radical scavengers that neutralize generated free radicals, or peroxide decomposition inhibitors that decompose generated peroxides into harmless substances and prevent the generation of new free radicals, and can be used alone or in combination of two or more.

[0181] Examples of antioxidants having a free radical scavenger effect may include phenolic compounds such as hydroquinone, 4-tert-butylcatechol, 2-tert-butylhydroquinone, hydroquinone monomethyl ether, 2,6-di-tert-butyl-p-cresol, 2,2-methylenebis(4-methyl-6-tert-butylphenol), 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, and 1,3,5-tris(3',5'-di-tert-butyl-4-hydroxybenzyl)-S-triazine-2,4,6-(1H,3H,5H)trione. 3H, 5H) trione); quinone-based compounds such as methylquinone and benzoquinone; amine-based compounds such as bis(2,2,6,6-tetramethyl-4-piperidinyl)-sebacate and phenothiazine. For example, IRGANOX 1010 (trade name, BASF Japan Co., Ltd.) and the like can be used as commercially available products.

[0182] Examples of the antioxidant having a peroxide decomposing effect may include phosphorus compounds such as triphenyl phosphite; and sulfur compounds such as pentaerythritol tetralaurylthiopropionate, dilaurylthiopropionate, and distearyl-3,3′-thiodipropionate.

[0183] For example, the antioxidant may be a phenolic compound, and the use of such a compound can suppress discoloration, enhance heat resistance, and reproduce better resolution.

[0184] Antioxidants, such as phenolic antioxidants, can be used in combination with heat-resistant stabilizers. Such a combination can exhibit greater effects.

[0185] Examples of heat-resistant stabilizers include phosphorus-based, hydroxylamine-based, and sulfur-based heat-resistant stabilizers. Such heat-resistant stabilizers can be used alone or in combination of two or more.

[0186] For example, the antioxidant can be a hydroxylamine-based antioxidant, a sulfur-based antioxidant, or a phenolic antioxidant. When a phenolic antioxidant is used, the blending amount of the phenolic antioxidant can be 0.01 to 5 wt% or 0.03 to 3 wt% relative to the total composition. When the blending amount of the antioxidant exceeds 0.01 to 1 wt%, the effects of adding the antioxidant can be reliably achieved. When the blending amount is 1 wt% or less, a good alkalinity phenomenon can be achieved without interrupting the photoreaction, and a good dry feel and coating film properties can be ensured.

[0187] <Organic Solvents>

[0188] The photosensitive resin composition of the present disclosure may include an organic solvent for use in preparing the composition or adjusting viscosity when applied to a substrate or base film. Examples of organic solvents include esters; aliphatic hydrocarbons such as octane and decane; petroleum-based solvents such as petroleum ether, petroleum naphtha, and solvent naphtha; and other commonly known and commonly used organic solvents. These organic solvents may be used alone or in combination of two or more.

[0189] <Other additives>

[0190] In addition, the photosensitive resin composition of the present disclosure may include other additives that are well-known and commonly used in the field of electronic materials. Examples of other additives may include thermal polymerization inhibitors, ultraviolet absorbers, plasticizers, flame retardants, antistatic agents, anti-aging agents, antimicrobial and antifungal agents, defoamers, leveling agents, thickeners, adhesives, thixotropic agents, photoinitiator aids, sensitizers, curing accelerators, release agents, surface treatment agents, dispersants, dispersing aids, surface modifiers, stabilizers, and the like.

[0191] In the photosensitive resin composition of the present disclosure, the content of phosphorus may be 500 ppm to 5000 ppm.

[0192] In the photosensitive resin composition, a phosphorus content of 500 ppm or more can improve surface curing and enhance gold plating resistance and adhesion, and a phosphorus content of 5000 ppm or less can show an effect of increasing the reaction rate of the silicone sealant.

[0193] Phosphorus levels below 500 ppm may result in a 3H pencil hardness, poor adhesion after gold plating, low gloss, and incomplete solder resist opening (SRO) formation. However, phosphorus levels exceeding 5000 ppm may result in a very slow reaction rate of the silicone encapsulant, low developability and reflectivity, and incomplete SRO formation.

[0194] [Dry film and its manufacturing method]

[0195] Another aspect of the present disclosure relates to a dry film having a photosensitive resin layer formed by coating and drying a photosensitive resin composition on a first film.

[0196] To produce a dry film, the composition of the present disclosure is first diluted with an organic solvent to have an appropriately adjusted viscosity, and then coated onto a first film to a uniform thickness, for example, 40 μm to 60 μm, using a notch wheel coater, knife coater, lip coater, rod coater, extrusion coater, reverse coater, transfer roll coater, gravure coater, micro gravure coater, or spray coater. Subsequently, the applied composition can be dried, typically at a temperature of 40°C to 120°C for 1 to 30 minutes, to form a photosensitive resin layer, ultimately producing a dry film.

[0197] The thickness of the coated film is not particularly limited, but generally, the thickness after drying may be 10 μm to 150 μm, 10 μm to 80 μm, or 10 μm to 60 μm.

[0198] As the first film, a plastic film can be used, and for example, a polyester film such as polyethylene terephthalate (PET), polyimide film, polyamide-imide film, polypropylene film, or polystyrene film can be used. For example, the plastic film can be polyethylene terephthalate. The thickness of the first film is not particularly limited, but is generally selected within the range of 10 μm to 150 μm. The composition can be applied to metal foils such as copper foil or aluminum foil. The already used first film can be subjected to a release treatment using acrylic resin, silicone, or the like.

[0199] The dry film disclosed herein is white and can therefore be used to reflect light generated by light-emitting diodes (LEDs) or electroluminescence (EL), which are used as light sources in lighting fixtures or backlights for liquid crystal displays (LCDs), such as mobile terminals, laptops, tablets, monitors, smartphones, personal computers, and televisions. The dry film disclosed herein can be applied to LEDs, illuminated printed circuit boards, and the like.

[0200] To prepare a cured film on a printed circuit board using a dry film, the second film protecting the dry film is removed, and the exposed resin layer of the dry film is covered and attached to a substrate having a circuit using a laminator, etc., thereby forming a resin layer on the substrate having a circuit. The formed resin layer can then be exposed, developed, heated, and then cured to form a cured film. The second film can be removed at any step before or after exposure.

[0201] [Current product and its preparation method]

[0202] The cured product of the present disclosure can be obtained by curing the photosensitive resin composition of the present disclosure or the solder resist layer of the dry film of the present disclosure.

[0203] The cured product of the present disclosure can be suitably used in printed circuit boards, electronic components, and the like. The cured product of the present disclosure has high crack resistance, high resolution, and outstanding dielectric properties (including a low dielectric constant and a low dielectric loss tangent). In addition, the cured product of the present disclosure can be excellent in heat resistance and linear expansion coefficient.

[0204] For example, the cured product of the present disclosure may be a solder resist.

[0205] The solder resist can be prepared by coating the photosensitive resin composition of the present disclosure on a substrate to form a photosensitive resin layer, selectively exposing the photosensitive resin layer through a photomask having a predetermined pattern using active energy rays, and then developing the unexposed portions with an alkaline aqueous solution (e.g., a 0.3 wt% to 3 wt% aqueous sodium carbonate solution) to form a pattern. Alternatively, in the case of a dry film, the first film of the dry film is peeled off, and then developed after exposure to form a patterned solder resist layer on the substrate. As long as this does not impair the properties, the first film can be peeled off from the dry film before exposure, and the exposed resin layer can then be exposed and developed.

[0206] [Printed circuit board and method of manufacturing the same]

[0207] The printed circuit board of the present disclosure may include a cured product of the photosensitive resin composition of the present disclosure or a cured film obtained by curing the photosensitive resin layer of the dry film of the present disclosure.

[0208] The printed circuit board disclosed herein may include a cured product obtained from the photosensitive resin composition disclosed herein or a photosensitive resin layer of a dry film. In the method for manufacturing a printed circuit board disclosed herein, for example, the viscosity of the photosensitive resin composition disclosed herein is adjusted to a level suitable for a coating method using an organic solvent, and the photosensitive resin composition is applied to a substrate using a method such as dip coating, flow coating, roller coating, bar coating, screen printing, or curtain coating. The organic solvent in the composition is then volatilized at a temperature of 60°C to 100°C and dried (pre-drying) to form a tacky-free resin layer. In the case of a dry film, the resin layer is bonded to the substrate using a laminator or the like to contact the substrate, and then the first film is separated to form the resin layer on the substrate.

[0209] Examples of substrates may include not only printed circuit boards and flexible printed circuit boards having circuits formed of copper or the like, but also FR-4 substrates and all grades of copper-clad laminates (FR-4, etc.), which use copper-clad laminate materials for high-frequency circuits, utilizing paper phenol, paper epoxy, glass fiber epoxy, glass polyimide, glass fiber / epoxy, glass fiber / paper epoxy, synthetic fiber epoxy, fluoroplastic-polyethylene-polyphenylene ether, polyphenylene oxide cyanate, etc., as well as other metal substrates, polyimide films, polyethylene terephthalate films, polyethylene naphthalate (PEN) films, glass substrates, ceramic substrates, wafer substrates, and the like.

[0210] Lamination of the dry film onto the substrate can be performed after applying pressure and heat using a vacuum laminator or the like. When using a substrate with circuitry, using such a vacuum laminator allows the dry film to adhere to the circuit substrate regardless of surface unevenness, thereby preventing the incorporation of air bubbles and improving the reduction of sink marks on the substrate surface. The pressure applied can be approximately 0.1 MPa to 2.0 MPa, and the temperature can be 40°C to 120°C.

[0211] In addition, post-curing of the cured product is performed by: i) active energy ray irradiation followed by heat curing (e.g., 100°C to 220°C), ii) heat curing followed by active energy ray irradiation, iii) active energy ray irradiation alone, or iv) heat curing alone, thereby forming a cured film having excellent properties such as adhesion and hardness.

[0212] The cured product of the present disclosure is cured by heating at a temperature of, for example, 100° C. to 220° C., thereby forming a cured film having excellent overall properties, such as high reflectivity, outstanding anti-yellowing properties, and excellent crack resistance.

[0213] The exposure device used for active energy ray irradiation can be a device equipped with a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a mercury arc lamp, etc., and irradiates ultraviolet (UV) light in the range of 350 nm to 450 nm, or a direct drawing device (for example, a laser direct imaging device that directly draws CAD data using a computer via laser) can be used. The direct drawing lamp light source or laser light source can have a maximum wavelength in the range of 350 nm to 450 nm. The exposure dose used for image formation varies depending on the thickness, etc., but can generally be 10 mJ / cm2 to 1000 mJ / cm2 or 20 mJ / cm2 to 800 mJ / cm2.

[0214] Development can be performed by dipping, showering, spraying, brushing, etc., and an alkaline aqueous solution such as potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, or amine can be used as a developing solution.

[0215] The printed circuit board of the present disclosure may include a dry film including one or more layers formed of a photosensitive resin composition.

[0216] In the formation of a printed circuit board, the dry film may be placed on a test substrate, and the dry film may be transferred to the test substrate through vacuum lamination.

[0217] Thereafter, the first film is peeled off, and the substrate onto which the dry film from which the first film has been peeled has been transferred can be subjected to UV exposure using an exposure device. During this exposure, the exposed portion (light-irradiated portion) can be cured. After exposure, the substrate is cooled at room temperature and then placed in a developing device, where the unexposed portion is developed with an alkaline aqueous solution, thereby completing the formation of the resist pattern. The substrate, patterned by development, is post-cured (post-cured) in an oven at 150°C for 1 hour, completing substrate manufacturing. After post-curing, a reflow process is performed, followed by a wafer mounting process. Then, a packaging process is performed by preparing a silicone sealant on the cured product of the photosensitive resin layer. The photosensitive resin composition disclosed herein can reduce outgassing of the photopolymerization initiator, thereby resolving yellowing and incomplete curing of the silicone sealant formed on the cured product and increasing the reaction rate of the silicone sealant.

[0218] In the method of manufacturing a printed circuit board including the cured product of the present disclosure, for example, the first film may be peeled off after the exposure process, followed by a lamination process.

[0219] [Silicone sealant layer and preparation method thereof]

[0220] The printed circuit board of the present disclosure may further include a silicone sealant layer disposed on the cured product (obtained by curing the photosensitive resin layer). The silicone sealant layer may be formed by applying a composition including silicone to seal and protect the printed circuit board or the solder mask layer.

[0221] In order to protect the light-emitting chip portion and the photosensitive resin layer (or the cured product obtained by curing the photosensitive resin layer), the above-mentioned silicone sealant layer can be applied.

[0222] An exemplary method for preparing the silicone sealant layer will be described below.

[0223] A dam with a width of 2.0 cm, a height of 2.0 cm, and a thickness of 250-300 μm was fabricated on a printed circuit board that had been post-cured or reflowed. A 1:1 mixture of any of silicone sealants A and B was then added thereto to apply a silicone sealant with a thickness of 250 μm to 300 μm. The silicone sealant was then subjected to a primary cure in an oven at 100°C for 2 hours and a secondary cure in an oven at 150°C for 4 hours to prepare a silicone sealant layer.

[0224] To measure the physical properties of the silicone sealant layer, the reaction rate of the silicone sealant and the amount of photopolymerization initiator remaining in the silicone sealant layer can be analyzed after peeling it off after curing is complete. Furthermore, the degree of cure (reaction rate) of the silicone sealant can be measured to check the degree of cure. The reflectivity of the silicone sealant layer can also be measured.

[0225] For example, the silicone sealant layer may include a lower sealant region proximate to the solder mask layer and an upper sealant region distal to the solder mask layer.

[0226] For example, the content of the photopolymerization initiator (E) included in the upper sealant region or the lower sealant region may be 1000 ppm or less, 900 ppm or less, 800 ppm or less, 700 ppm or less, 600 ppm or less, or 500 ppm or less, relative to the content of the photopolymerization initiator (E) included in the solder resist layer.

[0227] The amount of photopolymerization initiator included in the upper or lower sealant region is derived from the migration of the photopolymerization initiator included in the solder resist layer. That is, the photopolymerization initiator of the trimethylbenzylphosphine oxide-based compound (E) having at least one PO bond disclosed herein can be used to reduce the amount of photopolymerization initiator that migrates to the adjacent upper or lower sealant region.

[0228] For example, when the photopolymerization initiator is transferred to the silicone sealant layer due to outgassing diffusion, the silicone sealant does not fully cure due to the inhibition reaction between the phosphorus (P) component of the photopolymerization initiator and the catalyst component (e.g., platinum catalyst) of the silicone sealant layer. This decrease in the reaction rate of the silicone sealant can lead to problems related to long-term reliability.

[0229] [Protective film]

[0230] The laminate of the present disclosure may include a cured product and a protective film.

[0231] In the present disclosure, a protective film can be attached after the photosensitive resin layer is post-cured to form a cured product to remove the photopolymerization initiator. Due to the protective film's high affinity for photopolymerization initiators, the attachment of the protective film effectively removes residual photopolymerization initiators from the solder resist layer. Removing residual photopolymerization initiators can reduce the amount of residual photopolymerization initiator remaining after the flow and firing processes. When a silicone sealant is applied to the cured product layer, the reduced photopolymerization initiator content increases the silicone sealant's reaction rate, and this increased reaction rate can significantly improve long-term reliability.

[0232] The protective film may be, for example, a polyethylene film, a polytetrafluoroethylene film, a polypropylene film, a surface-treated paper, etc. The thickness of the protective film is not particularly limited, but may be, for example, 10 μm to 150 μm.

[0233] For example, the content of the photopolymerization initiator (E) included in the protective film may be 1000 ppm or less relative to the content of the photopolymerization initiator (E) included in the solder resist layer.

[0234] The content of the photopolymerization initiator included in the protective film is derived from the migration of the photopolymerization initiator included in the solder resist layer. That is, the photopolymerization initiator based on the trimethylbenzylphosphine oxide compound (E) disclosed herein having at least one PO bond can be used to reduce the content of the photopolymerization initiator that migrates to the nearby protective film.

[0235] <Example>

[0236] Hereinafter, the present disclosure will be described in detail with reference to Examples. The present disclosure is not limited to the following Examples.

[0237] <Synthesis Example 1: Alkali-soluble resin A, copolymer resin>

[0238] In a flask equipped with a thermometer, stirrer, dropping funnel, and reflux condenser, 325.0 parts by weight of dipropylene glycol monomethyl ether (dipropylene glycol monomethyl ether) was heated to 110°C as a solvent. A mixture of 174.0 parts by weight of methacrylic acid, 174.0 parts by weight of ε-caprolactone-modified methacrylic acid (average molecular weight: 314), 77.0 parts by weight of methyl methacrylate, 222.0 parts by weight of dipropylene glycol monomethyl ether, and 12.0 parts by weight of tert-butyl peroxy-2-ethylhexanoate (Nichiyu's fully butylated-O) was added dropwise over 3 hours. The mixture was stirred at 110°C for 3 hours, and the polymerization catalyst was then deactivated to obtain a resin solution. The resin solution was cooled, and then 289.0 parts by weight of cyclopolymer M100 (Daicel), 3.0 parts by weight of triphenylphosphine, and 1.3 parts by weight of hydroquinone monomethyl ether were added. The temperature was raised to 100° C., and the mixture was stirred to perform a ring-opening addition reaction of the epoxy ring, thereby obtaining a resin solution A. The obtained resin solution A had a solid content of 54.5 wt %, and an acid value of the solid content of 79.8 mgKOH / g.

[0239] <Synthesis Example 2: Resin Solution D>

[0240] In an internal pressure vessel equipped with a thermometer, cooling tube, and stirrer, 200 parts by weight of deionized water and 0.3 parts by weight of sodium sulfate were injected and confirmed to be dissolved. Then, 5 parts by weight of benzoyl peroxide (BPO) as a polymerization initiator and 5 parts by weight of α-methylstyrene dimer (MSD) as a chain transfer agent were added to a mixture of 10.4 parts by weight of methyl methacrylate (MMA), 5 parts by weight of n-butyl acrylate (n-BA), 24.6 parts by weight of methacrylic acid (MAA), and 60 parts by weight of styrene and dissolved thoroughly. A dispersant was then added to a concentration of 300 ppm, and the furnace interior was purged with nitrogen with thorough stirring. The temperature was then raised to carry out suspension polymerization. After completion of polymerization, the resulting suspension was filtered through a 30 μm mesh and dried under hot air at 40°C to obtain pelletized resin. The obtained granular resin (copolymer resin) was fully dissolved using dipropylene glycol methyl ether (DPM) as an organic solvent to achieve a solid concentration of 50 wt%, and this solution was referred to as resin solution D. The solid acid value was 160 mgKOH / g.

[0241] <Synthesis Example 3: Carboxyl-containing cresol novolac epoxy acrylate resin A-2>

[0242] In a four-necked flask equipped with a stirrer and a reflux condenser, 220 parts by mass of a cresol novolac-type epoxy resin was placed, and 214 parts by mass of carbitol acetate was added and dissolved by heating. Subsequently, 0.1 parts by mass of hydroquinone as a polymerization inhibitor and 2.0 parts by mass of dimethylbenzylamine as a reaction catalyst were added to prepare a mixture. This mixture was heated to 95°C to 105°C, and 72 parts by mass of acrylic acid was slowly added dropwise, followed by a 16-hour reaction. The reaction product was cooled to 80°C to 90°C, and 106 parts by mass of tetrahydrophthalic anhydride was added. The reaction was allowed to proceed for 8 hours, followed by cooling and removal of the contents.

[0243] The photosensitive resin thus obtained, which contained ethylenically unsaturated bonds and carboxyl groups, had a nonvolatile content of 64%, a solid acid value of 84.4 mgKOH / g, and a weight-average molecular weight (Mw) of approximately 7500. This resin is hereinafter referred to as (A-2). The weight-average molecular weight of the obtained resin was measured by GPC. [ , , ]

[0244] [Preparation of photosensitive resin composition]

[0245] Table 1

[0246] Content of each component of the photosensitive resin composition (unit: based on the mass percentage relative to the total composition, each value is rounded to three decimal places, provided that in Example 2, the weight percentage is calculated relative to the total weight of the composition of Example 1). [Component] [Example] [1] [Example] [2] [Example] [3] [Example] [4] [Example] [5] [Example] [6] [Example] [7] [Example] [8] [Example] [9] [Example]

[10] [(A)] 12.50 12.50 12.50 12.50 12.50 12.50 32.00 32.00 32.00 32.00 [(A-1)] 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 [(A-2)] 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 [(A-3)] 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 [(B)] [Titanium oxide] 47.70 47.04 47.70 47.70 24.35 0.00 60.00 62.00 54.00 65.00 [(B)] [Silicon dioxide] 1.00 1.00 1.00 1.00 24.35 24.35 1.00 1.00 1.00 1.00 [(B)] [BaSO , 4, ] 0.00 0.00 0.00 0.00 0.00 24.35 0.00 0.00 0.00 0.00 [(C)] 1.50 1.50 1.50 1.50 1.50 1.50 0.00 3.00 0.00 0.00 [(D)] 2.50 2.50 2.50 2.50 2.50 2.50 5.00 0.00 0.00 0.00 [(F)] 0.50 0.50 0.50 0.50 0.50 0.50 0.00 0.00 0.00 0.00 [(G)] 11.00 11.00 11.00 11.00 11.00 11.00 0.00 0.00 11.0 0.00 [Photopolymerization initiator] [A] 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 [Photopolymerization initiator] [E-1] 2.00 2.66 0.00 1.00 0.00 0.00 0.00 0.00 0.00 0.00 [Photopolymerization initiator] [E-2] 0.00 0.00 2.00 1.00 2.00 2.00 2.00 2.00 2.00 2.00 [Photopolymerization initiator (oxime-based)] 0.60 0.60 0.60 0.60 0.60 0.60 0.00 0.00 0.00 0.00 [Epoxy resin] 9.50 9.50 9.50 9.50 9.50 9.50 0.00 0.00 0.00 0.00 [Acrylic resin] 9.50 9.50 9.50 9.50 9.50 9.50 0.00 0.00 0.00 0.00 [Thermal Curing Catalyst] 1.00 1.00 1.00 1.00 1.00 1.00 0.00 0.00 0.00 0.00 [Dispersant] 0.50 0.50 0.50 0.50 0.50 0.50 0.00 0.00 0.00 0.00 [Antioxidants] 0.20 0.20 0.20 0.20 0.20 0.20 0.00 0.00 0.00 0.00 [sum] 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 [Component] [Comparative Example] [1] [Comparative Example] [2] [Comparative Example] [3] [Comparative Example] [4] [Comparative Example] [5] [Comparative Example] [6] [Comparative Example] [7] [(A)] 12.50 0.00 0.00 0.00 12.50 12.50 32.00 [(A-1)] 0.00 12.50 0.00 0.00 0.00 0.00 0.00 [(A-2)] 0.00 0.00 12.50 0.00 0.00 0.00 0.00 [(A-3)] 0.00 0.00 0.00 12.50 0.00 0.00 0.00 [(B)] [Titanium oxide] 47.70 47.70 47.70 47.70 49.70 43.70 65.00 [(B)] [Silicon dioxide] 1.00 1.00 1.00 1.00 1.00 1.00 1.00 [(B)] [BaSO , 4, ] 0.00 0.00 0.00 0.00 0.00 0.00 0.00 [(C)] 1.50 1.50 1.50 1.50 1.50 1.50 0.00 [(D)] 2.50 2.50 2.50 2.50 2.50 2.50 0.00 [(F)] 0.50 0.50 0.50 0.50 0.50 0.50 0.00 [(G)] 11.00 11.00 11.00 11.00 11.00 11.00 0.00 [Photopolymerization initiator] [A] 2.00 2.00 2.00 2.00 0.00 6.00 2.00 [Photopolymerization initiator] [E-1] 0.00 0.00 0.00 0.00 0.00 0.00 0.00 [Photopolymerization initiator] [E-2] 0.00 0.00 0.00 0.00 0.00 0.00 0.00 [Photopolymerization initiator (oxime-based)] 0.60 0.60 0.60 0.60 0.60 0.60 0.00 [Epoxy resin] 9.50 9.50 9.50 9.50 9.50 9.50 0.00 [Acrylic resin] 9.50 9.50 9.50 9.50 9.50 9.50 0.00 [Thermal Curing Catalyst] 1.00 1.00 1.00 1.00 1.00 1.00 0.00 [Dispersant] 0.50 0.50 0.50 0.50 0.50 0.50 0.00 [Antioxidants] 0.20 0.20 0.20 0.20 0.20 0.20 0.00 [sum] 100.00 100.00 100.00 100.00 100.00 100.00 100.00 Resin solution A synthesized above (weight average molecular weight: g / mol) (A-1) EPICLON R-2000K, manufactured by DIC Co., Ltd., Japan: Contains cresol phenolic acid (weight average molecular weight: 7500 g / mol) (A-2) EPICLON R-2000, manufactured by DIC Co., Ltd., Japan: Contains cresol phenolic acid (weight average molecular weight: 7500 g / mol, acid value: 54 mgKOH / g, solid acid value: 84.4 mgKOH / g, solid content: 64 wt%) (A-3) ZAR-1035, manufactured by Nippon Chemical Co., Ltd.: Contains bisphenol (weight average molecular weight: 8000 g / mol, solid acid value: 100 mgKOH / g, solid content: 64 wt%) (B) Rutile titanium oxide, R-931 manufactured by DuPont Ltd.: (average particle size: 0.36 μm) (B) Silica ADMAFINE SO-E2, manufactured by Admatex (B) Barium sulfate (BaSO4, B-30, manufactured by Sakai Chemical Co., Ltd.) (C) Mercapto-modified (meth)acrylate, ES110N from Miwon Specialty Chemical Co., Ltd. (weight average molecular weight: 340 g / mol, obtained by mixing pentaerythritol tetrakis(3-mercaptopropionate) and trimethylolpropane triacrylate) (D) Resin solution D synthesized above (F) Silane coupling agent, KBE-403, manufactured by Shinetsu Chemical Co., Ltd. (3-glycidoxy propyltriethoxysilane) (G) Ebecryl 210 resin with urethane linkages, manufactured by Daicel-Allnex Co., Ltd. (aromatic urethane diacrylate oligomer) Photopolymerization initiator A: 2,4,6-trimethylbenzyldiphenylphosphine oxide Photopolymerization initiator E-1: Omnipol TP (Made from IGM resin) (a+b+c=1 to 20) Photopolymerization initiator E-2: Omnirad TPO L (Made from IGM resin) Photopolymerization initiator, oxime-based: Oxime ester initiator IRGACURE OXE02 (manufactured by BASF Japan Co., Ltd.) Epoxy resin: jER828 (bisphenol A type epoxy resin, manufactured by Mitsubishi Chemical) Acrylic resin: KAYARAD DPCA-60, manufactured by Japan Explosives Co., Ltd. Thermal curing catalyst: melamine, dicyandiamide, manufactured by Mitsubishi Chemical Dispersant: Disperbyk-110, manufactured by BYK GmbH Antioxidant: Phenolic antioxidant IRGANOX 1010 (manufactured by BASF Japan Co., Ltd.)

[0247] [Preparation of dry film of photosensitive resin composition]

[0248] Each composition of the Examples and Comparative Examples was coated to a uniform thickness (50 μm) on a first film (PET film; XD-500P manufactured by Toray Co., Ltd., film thickness: 25 μm) using a notch wheel coater in a clean room. (2) The coated resin composition was dried in four temperature chambers (chamber 1: 60 °C, chamber 2: 80 °C, chamber 3: 100 °C, chamber 4: 100 °C) ranging from 40 °C to 120 °C. (3) The properly dried coating film on the first film was combined with a second film (polypropylene (PP) film) to prepare a dry film. Specifically, the thickness of the dry coating film was 60 μm.

[0249] Evaluation Example 1: Measurement of Outgassing Content, Silicone Sealant Reaction Rate, and Photopolymerization Initiator Content

[0250] Determination of outgassing content

[0251] The photosensitive resin composition of each example and comparative example was laminated on a PET film using a vacuum laminator (CVP-300, Nichigo-Morton) with a first chamber temperature of 60° C., a vacuum pressure of 3 hPa, and a vacuum time of 10 seconds to prepare a dry film, and then the PET film was peeled off.

[0252] Full-surface exposure was performed using a Screen Corporation DI exposure unit at 300 mJ / cm², measured with an integrated photometer, while a Kodak Step Tablet No. 2 (41 steps) with 23 steps set as a photomask was used. Subsequently, development was performed using a 1.0% Na₂CO₃ aqueous solution at 30°C for 60 seconds at a spray pressure of 0.2 MPa. Afterward, curing was performed in an oven at 150°C for 60 minutes to obtain a cured photosensitive resin layer.

[0253] Powder samples were collected from the fabricated resist layer and placed in a thermal desorption unit (TDU) manufactured by GERSTEL Co., Ltd. Specifically, using helium as a purge gas (50 ml / min), the powder sample was heated at 150°C for 60 minutes, starting from 30°C at a temperature increase rate of 60°C / min, and then desorbed and collected at -50°C. The collected outgassing components were separated and analyzed using a gas chromatograph-mass spectrometer (8890 / 5977B) manufactured by Agilent Technologies Co., Ltd. to quantify the conversion rate of n-dodecane. The weight percentage of the outgassing components was then measured based on the weight of the photopolymerization initiator included in the cured product of the photosensitive resin layer.

[0254] Gas chromatography measurement conditions are as follows: Column: Capillary column DB-1MS, manufactured by Agilent Technologies (length: 30 m, inner diameter: 0.25 mm, thickness: 0.25 μm), Detector: MS (ITQ900), Carrier gas: Helium, Injector temperature: 300°C, Detector temperature: 230°C, Column temperature conditions: Initial temperature: 50°C, hold at 50°C for 2 minutes after sample injection, then increase the temperature to 300°C at a rate of 12°C / s, and hold at 300°C for 10 minutes.

[0255] Separately, as described below, a silicone sealant (obtained by laminating a dry film of a photosensitive resin composition on an FR-4 Cu film and then peeling off the PET) was formed on the substrate and then cured by heating at 100°C for 2 hours and then at 150°C for 4 hours.

[0256] The outgassing content, silicone reaction rate, and the content of the photopolymerization initiator transferred to the silicone sealant and protective film in each of Examples and Comparative Examples were measured and shown in the following Table 2. The respective measurement methods are described below.

[0257] [Measurement method of outgassing]

[0258] The photopolymerization initiator peak was analyzed using TD-GCMS. The peak unit is expressed as μg / g, representing the amount of gas (in μg) generated as n-dodecane per 1g of sample. The total outgassing from the photopolymerization initiator peak was measured. Specifically, the ratio of the photopolymerization initiator peak area to the area of ​​n-dodecane, which serves as the reference for GC-MS, was calculated (the calculation formula is provided below).

[0259] Calculation formula: photopolymerization initiator analysis peak area / n-dodecane measurement peak area.

[0260] 2. Measurement of silicone sealant reaction rate and photopolymerization initiator content

[0261] [Calculation of silicone sealant reaction rate and photopolymerization initiator content]

[0262] Each dry film of the photosensitive resin composition (white solder resist composition) was laminated on the FR-4 Cu film using a vacuum laminator (CVP-300, Nichigo-Morton) with the first chamber temperature at 60°C, the vacuum pressure at 3 hPa, and the vacuum time at 10 seconds, and then the PET film was peeled off.

[0263] Exposure was performed using a DI exposure system manufactured by Screen at 300 mJ / cm², measured with an integrated photometer, using a Kodak Step Tablet No. 2 (41 steps) with 23 steps set as a photomask. Subsequently, development was performed using a 1.0% Na₂CO₃ aqueous solution at 30°C for 60 seconds at a spray pressure of 0.2 MPa. Curing was then performed in an oven at 150°C for 60 minutes to obtain a cured product (solder resist) of the photosensitive resin layer.

[0264] A dam measuring 2.0 cm wide, 2.0 cm high, and 250-300 μm thick was fabricated and attached to both ends of the cured product of the photosensitive resin layer on the FR-4 Cu film. A 1:1 mixture of silicone sealants A and B was added to the space formed by the dam, laminating a silicone sealant layer with a thickness of 250 to 300 μm. The silicone sealant was then cured in an oven at 100°C for 2 hours, followed by a secondary cure at 150°C for 4 hours. After the secondary cure, the interface between the cured product of the photosensitive resin layer and the silicone sealant layer was separated using a knife. The reaction rates of the upper and lower sealant regions of the silicone sealant layer, as well as the degree of cure of the silicone sealant within the silicone sealant layer, were then measured on a ZnSe crystal plate using an FT-IR system.

[0265] [Calculation method of silicone reaction rate]

[0266] 1) Silicone samples without primary and secondary curing and silicone samples with secondary curing (upper and lower parts) were prepared.

[0267] 2) Uncured silicone and cured silicone were placed on a ZnSe crystal plate and subjected to FT-IR measurements.

[0268] 3) Calculate the reaction rate by comparing the Si-H peak of the cured silicone with the Si-H peak in the adjacent region (2160-1), using the uncured silicone as the reference (calculation formula provided below).

[0269] Calculation formula: Si-H peak height of cured silicone / Si-H peak height of uncured silicone × 100

[0270] (2) The content of photopolymerization initiator was measured by gel permeation chromatography while using a silicone sealant separated by a knife.

[0271] Specifically, a 0.05g sample of the analyte, representing the secondary post-cured silicone sealant, was separated from the silicone sealant layer formed on the cured product of the photosensitive resin layer using a knife. This 0.05g sample was dissolved in 10.0g of THF and then placed in a vial. An ultrasonic vibrator was used for 5 minutes to dissolve any undissolved photosensitive resin composition. Subsequently, 100μl of the sample was injected into a gel permeation chromatography (GPC) instrument and analyzed.

[0272] [Calculation of the Content of Photopolymerization Initiator Transferred to the Protective Film]

[0273] A PF protective film was attached to a secondary cured silicone sealant and placed at 40°C and 90% humidity for 24 hours. The PF protective film was then peeled off, and a 0.05 g sample of the silicone sealant layer formed on the cured product of the photosensitive resin layer was separated with a knife to prepare the PF protective film analyte sample. This 0.05 g analyte sample was dissolved in 5.0 g of tetrahydrofuran (THF) and placed in a vial. An ultrasonic vibrator was used for 5 minutes to dissolve any undissolved photosensitive resin composition into the solution, thereby preparing the sample. Afterwards, 100 μl of the sample was injected into a gel permeation chromatography (GPC) instrument and analyzed.

[0274] [Gel Permeation Chromatography (GPC) Measurement Method and Measurement Conditions for Photopolymerization Initiator Content Analysis]

[0275] The sample was injected into a GPC instrument (GPC instrument name: E2695 Water Separation Module, detector: 2998 PDA / 2414 RI, flow rate: 0.5 ml / min, columns: HSP Gel HR MB-L 2.0 and HSP Gel HR 1.0, measurement temperature: 4°C, mobile phase: THF). The calculation method quantified and analyzed the peak at the absorption wavelength of 382 nm for TPO, a photopolymerization initiator. The sampled analyte and TPO were used as the REF photopolymerization initiator sample. The same procedure was performed for samples containing 1 ppm, 10 ppm, and 100 ppm of TPO to obtain a calibration curve. The calibration curve results obtained at each concentration were used to quantify the photopolymerization initiator in the sample.

[0276] (Evaluation of outgassing amount) ◎: Outgassing content <500 ppm ○:500 ppm≤Outgassing content<1000 ppm △:1000 ppm≤Outgassing content<2000 ppm X: 2000 ppm≤ outgassing content (Evaluation of the reaction rate of silicone sealant) ◎:70%≤Reaction rate of silicone sealant ○:55%≤Reaction rate of silicone sealant<70% △:40%≤Reaction rate of silicone sealant<55% X: Reaction rate of silicone sealant <40% (Evaluation of the reaction rate of silicone sealant) ◎:50%≤lower silicone sealant reaction rate ○:40%≤Silicone sealant reaction rate<50% △:30%≤lower silicone sealant reaction rate<40% X: Reaction rate of silicone sealant <30% (Content of photopolymerization initiator transferred to sealant) ◎: Photopolymerization initiator content <300 ppm ○:300 ppm≤Photopolymerization initiator content<500 ppm △:500 ppm≤Photopolymerization initiator content<700 ppm X: 700 ppm ≤ Photopolymerization initiator content

[0277] Table 2 Outgassing content Reaction rate of silicone sealant Reaction rate of silicone sealant Photopolymerization initiator content transferred to sealant Comparative Example 1 X △ △ X Comparative Example 2 X △ △ X Comparative Example 3 X △ △ X Comparative Example 4 X △ △ X Comparative Example 5 ◎ ◎ ◎ ◎ Comparative Example 6 X X X X Comparative Example 7 X △ △ X Example 1 ◎ ◎ ◎ ◎ Example 2 ◎ ◎ ◎ ◎ Example 3 ○ ◎ ◎ ◎ Example 4 ◎ ◎ ◎ ◎ Example 5 ○ ◎ ◎ ◎ Example 6 ○ ◎ ◎ ◎ Example 7 ○ ◎ ◎ ◎ Example 8 ○ ◎ ◎ ◎ Example 9 ○ ◎ ◎ ◎ Example 10 ○ ◎ ◎ ◎

[0278] Referring to Table 2, Examples 1 to 10, which included photopolymerization initiator 1 or 2, exhibited significantly lower outgassing levels than Comparative Examples 1 to 4, 6, and 7. This significant reduction in outgassing from photopolymerization initiators can address the yellowing issue of silicone sealants and significantly increase the reaction rate of silicone sealants. This reduction in the amount of photopolymerization initiator transferred to the silicone sealant can improve the long-term reliability and stability of the product.

[0279] In Comparative Examples 1 to 4, 6, and 7 using TPO as a photopolymerization initiator, as described above, the transferred photopolymerization initiator TPO remained in a content of 700 ppm or more in the silicone sealant, resulting in reduced reflectivity and reaction rate of the silicone sealant and problems associated with long-term reliability of the product.

[0280] In Examples 1 and 2, which used only Omnipol TP as the photopolymerization initiator, the outgassing level of the photopolymerization initiator and the level of photopolymerization initiator transferred to the silicone sealant were significantly reduced, thereby maintaining high reflectivity, increasing the reaction rate in the sealant area, and improving the long-term reliability and stability of the product.

[0281] In Examples 3 to 10, which used Omnirad TPO L as the photopolymerization initiator, the outgassing content and the content of photopolymerization initiator transferred to the silicone sealant were significantly reduced, thereby maintaining high reflectivity, increasing the reaction rate in the sealant area, and improving the long-term reliability and stability of the product.

[0282] Next, a protective film (PF) was formed on the silicone sealant and maintained at 40°C / 90% humidity for 24 hours, after which only the protective film was peeled off. The amount of photopolymerization initiator transferred to the protective film was then measured using gel permeation chromatography, as shown in Table 3 below.

[0283] (Evaluation of Photopolymerization Initiator Content) ◎: Photopolymerization initiator content <500 ppm ○:500 ppm≤Photopolymerization initiator content<2000 ppm △:2000 ppm≤Photopolymerization initiator content<4000 ppm X: 4000 ppm≤ photopolymerization initiator content

[0284] Table 3 Content of photopolymerization initiator transferred to protective film Comparative Example 1 △ Comparative Example 2 △ Comparative Example 3 △ Comparative Example 4 △ Comparative Example 5 ◎ Comparative Example 6 X Comparative Example 7 △ Example 1 ◎ Example 2 ◎ Example 3 ◎ Example 4 ◎ Example 5 ◎ Example 6 ◎ Example 7 ◎ Example 8 ◎ Example 9 ◎ Example 10 ◎

[0285] Referring to Tables 3 and 2, Examples 1 to 10, which included photopolymerization initiators 1 or 2, exhibited significantly lower outgassing levels than Comparative Examples 1 to 4, 6, and 7, which included other photopolymerization initiators. Consequently, the amount of photopolymerization initiator transferred not only to the silicone sealant but also to the protective film was significantly reduced. Specifically, Examples 1 to 10 exhibited significantly less photopolymerization initiator transfer to the protective film (PF) compared to Comparative Examples 1-4, 6, and 7. This demonstrates that the use of the photopolymerization initiators represented by Chemical Formulas 1 and 2 reduces outgassing, and that this reduction in outgassing prevents the transfer of photopolymerization initiator to the silicone sealant and protective film. Therefore, the use of the photopolymerization initiators defined in this disclosure can increase reflectivity and improve the reaction rate and degree of curing of the silicone sealant, thereby enhancing long-term reliability.

[0286] Evaluation Example 2: BHAST Test

[0287] Each dry film prepared in Examples 3 and 4 and Comparative Examples 1 to 4 was laminated onto a substrate with comb-shaped electrodes (line / space = 50 μm / 50 μm) using a vacuum laminator (CVP-300, Nichigo-Morton) at a first chamber temperature of 60°C, a vacuum pressure of 3 hPa, and a vacuum time of 10 seconds. The films were then pressed under a pressure of 0.2 MPa and a pressing time of 10 seconds to produce evaluation substrates. The PET film was peeled off and then exposed using a DI exposure device (Screen) using the exposure dose obtained in step 23 of a Step Tablet (41 steps). The films were then developed (1% by mass Na₂CO₃, 30°C, 0.2 MPa) for 60 seconds to complete the substrate production. Following completion, the substrates were subjected to BHAST in a chamber at 110°C, 85% RH, and 20 V for 250 hours to evaluate insulation reliability, BHAST resistance, and reflectivity.

[0288] The BHAST test results are shown in Figures 1a and 1b.

[0289] After the BHAST test, the reflectance was measured and is shown in the following Table 4. The reflectance was measured at a wavelength of 450 nm using a spectrophotometer (CM-2600d, Konica Minolta Sensing Co., Ltd.). ◎:90%≤Reflectivity ○:87%≤Reflectivity<90% △:84%≤Reflectivity<87% X: Reflectivity <84%

[0290] In addition, HAST resistance tests were conducted and the results are shown in Table 4 below.

[0291] Each of the dry films prepared in Examples and Comparative Examples was laminated on a substrate having comb-shaped electrodes (line / space = 50 μm / 50 μm) using a vacuum laminator (CVP-300, Nichigo-Morton Co., Ltd.) at a first chamber temperature of 60 ° C., a vacuum pressure of 3 hPa, and a vacuum time of 10 seconds, and then pressed under a pressure of 0.2 MPa and a pressing time of 10 seconds to obtain an evaluation substrate.

[0292] The PET film was peeled off, and the exposure was measured at 300 mJ / cm² using an integrated photometer. Development was then performed with a 1.0% aqueous Na₂CO₃ solution at 30°C for 60 seconds at a spray pressure of 0.2 MPa. The resulting cured coating formed a dry film that was then cured in an oven at 150°C for 60 minutes to produce a HAST evaluation substrate. The evaluation substrate was placed in a high-temperature, high-humidity bath at 110°C and 85% humidity, charged at 20V, and subjected to a Highly Accelerated Stress Test (HAST) for 250 hours. After 250 hours, the cured coating was evaluated for discoloration and elution according to the following evaluation criteria (Equipment Manufacturer: Espec Co., Ltd., Ion Migration System, Equipment Name: NY IM1064). ○: No peeling, discoloration, or elution was observed. X: Peeling, discoloration, or elution is often observed with the naked eye.

[0293] Table 4 Reflectivity Substrate:Cu electrode Reflectivity Substrate: FR-4 substrate BHAST resistance Comparative Example 1 △ ○ X Comparative Example 2 X △ X Comparative Example 3 X X X Comparative Example 4 X X X Example 3 ○ ◎ ○ Example 4 ○ ○ ○

[0294] Referring to Table 4, the reflectivity after HAST testing was higher in Examples 3 and 4 compared to Comparative Examples 1 to 4. In addition, compared to Comparative Examples 1 to 4, Examples 3 and 4 showed higher reflectivity after HAST testing, very low copper oxidation and corrosion, and no peeling, discoloration, or dissolution.

[0295] Evaluation Example 3: Reflectivity Test (After Reflow and UV Treatment)

[0296] Each of the dry films prepared in Examples 1 to 4 and Comparative Examples 1 to 7 was laminated on a copper substrate using a vacuum laminator (CVP-300, Nichigo-Morton Co., Ltd.) at a first chamber temperature of 60°C, a vacuum pressure of 3 hPa, and a vacuum time of 10 seconds, and then pressed under conditions of a pressure of 0.2 MPa and a pressing time of 10 seconds.

[0297] The PET film was peeled off and then exposed using a DI exposure apparatus manufactured by Screen Corporation at 300 mJ / cm². Measurements were made using an integrated photometer, with a Kodak Step Tablet No. 2 (41 steps) set at 23 steps as a photomask. Subsequently, development was performed using a 1.0% Na₂CO₃ aqueous solution at 30°C for 60 seconds at a spray pressure of 0.2 MPa. The film was then cured in an oven at 150°C for 60 minutes to obtain a substrate. The reflectance of the coating surface of the resulting substrate was measured at a wavelength of 450 nm using a spectrophotometer (CM-2600d, Konica Minolta Sensing Co., Ltd.). Reflow was performed one to three times at 260°C for 10 seconds, and the reflectance was measured. The results are shown in Table 5. After post-curing, UV light was passed through the integrated photometer three times at 500 mJ / cm², and the reflectance was measured each time. The results are shown in Table 6. ◎:90%≤Reflectivity ○:87%≤Reflectivity<90% △:84%≤Reflectivity<87% X: Reflectivity <84%

[0298] Table 5 laboratory Average reflectivity (%) 450 nm Reflectivity (%) Process L a b Example 1 initial 97.23 -1.54 1.99 ◎ ◎ After reflow once 97.07 -1.5 2.47 ◎ ◎ Reflow once + firing 96.92 -1.32 2.67 ◎ ◎ Example 2 initial 97.22 -1.56 1.93 ◎ ◎ After reflow once 97.16 -1.55 2.46 ◎ ◎ Reflow once + firing 97.04 -1.5 2.63 ◎ ◎ Example 3 initial 97.08 -1.58 1.91 ◎ ◎ After reflow once 97.09 -1.52 2.66 ◎ ◎ Reflow once + firing 96.95 -1.5 2.76 ◎ ◎ Example 4 initial 97.17 -1.58 1.95 ◎ ◎ After reflow once 97.12 -1.49 2.85 ◎ ◎ Reflow once + firing 96.99 -1.4 2.97 ◎ ◎ Comparative Example 1 initial 97.01 -1.74 1.99 ◎ ◎ After reflow once 96.93 -1.7 2.62 ◎ ◎ Reflow once + firing 96.83 -1.6 3.11 ○ ○ Comparative Example 2 initial 90.89 -1.63 5.72 △ △ After reflow once 90.85 -1.62 5.94 △ △ Reflow once + firing 90.72 -1.58 6.42 △ X Comparative Example 3 initial 90.73 -1.56 5.99 △ △ After reflow once 90.71 -1.53 6.32 △ △ Reflow once + firing 90.34 -1.5 6.33 △ X Comparative Example 4 initial 88.12 -1.61 9.99 X X After reflow once 87.79 -1.6 10.22 X X Reflow once + firing 87.34 -1.58 11.32 X X Comparative Example 5 initial 90.59 -1.43 6.12 △ △ After reflow once 90.45 -1.42 6.42 △ △ Reflow once + firing 90.12 -1.28 6.71 △ X Comparative Example 6 initial 90.69 -1.63 5.72 △ △ After reflow once 90.55 -1.62 5.94 △ △ Reflow once + firing 90.32 -1.58 6.39 △ △ Comparative Example 7 initial 95.71 -1.43 1.71 ◎ ○ After reflow once 95.51 -1.42 2.37 ○ ○ Reflow once + firing 95.42 -1.4 3.01 ○ △

[0299] The initial reflectivity without performing the reflow process, and the reflectivity at 450 nm after the reflow process once, twice, and three times, and after the reflow process once and the firing process in Examples 1 to 4 are higher than those in Comparative Examples 1 to 7, indicating that the reflectivity reduction after reflow or firing is minimized.

[0300] Specifically, in Examples 1 to 4, using Omnipol TP or Omnirad TPO-L as a photopolymerization initiator resulted in minimal outgassing, which had little effect on the silicone sealant, allowing the firing process to be omitted. Consequently, high reflectivity was achieved even after reflow.

[0301] However, for Comparative Examples 1 to 7, a firing step to remove the TPO is required after the reflow process for backlight unit applications, as the TPO photopolymerization initiator affects the curability of the silicone sealant. Furthermore, this firing process significantly reduces reflectivity.

[0302] In summary, Examples 1 to 4 exhibited excellent reflectivity at an equivalent or higher level than Comparative Examples 1 to 7 even when applied to actual products, and, as previously discussed in Table 2, demonstrated the excellent reaction rate and degree of curing of the silicone sealant, thereby improving the long-term durability and stability of the product.

[0303] Table 6

[0304] Reflectivity evaluation after post-curing and UV treatment Laboratory (color difference) Average reflectivity (%) 450 nm reflectivity (%) Number of UV treatments L a b Example 1 0 97.23 -1.54 1.83 ◎ ◎ 1 97.11 -1.49 2.27 ◎ ◎ 2 97 -1.45 2.35 ◎ ◎ 3 96.8 -1.38 2.64 ◎ ◎ Example 2 0 97.22 -1.56 1.82 ◎ ◎ 1 97.1 -1.51 2.25 ◎ ◎ 2 97.01 -1.5 2.32 ◎ ◎ 3 96.81 -1.41 2.62 ◎ ◎ Example 3 0 97.08 -1.58 1.82 ◎ ◎ 1 97.01 -1.4 2.25 ◎ ◎ 2 96.95 -1.33 2.3 ◎ ◎ 3 96.81 -1.3 2.62 ◎ ◎ Example 4 0 97.17 -1.58 1.8 ◎ ◎ 1 97.08 -1.5 2.25 ◎ ◎ 2 96.89 -1.45 2.27 ◎ ◎ 3 96.8 -1.33 2.6 ◎ ◎ Comparative Example 1 0 97.01 -1.74 1.98 ◎ ◎ 1 96.99 -1.7 2.3 ◎ ◎ 2 96.85 -1.62 2.62 ○ ◎ 3 96.7 -1.6 2.8 ○ ○ Comparative Example 2 0 90.89 -1.63 3.97 △ △ 1 90.79 -1.62 4.03 △ △ 2 90.65 -1.53 4.22 △ X 3 90.53 -1.49 4.35 △ X Comparative Example 3 0 90.73 -1.7 4.01 △ △ 1 90.7 -1.62 4.07 △ △ 2 90.61 -1.58 4.35 △ X 3 90.52 -1.55 4.38 △ X Comparative Example 4 0 88.12 -1.61 7.02 X X 1 88.07 -1.59 7.5 △ X 2 88.03 -1.55 8.12 △ X 3 87.99 -1.51 8.25 △ X Comparative Example 5 0 90.59 -1.41 6.12 △ △ 1 90.39 -1.42 6.33 △ △ 2 90.25 -1.43 6.45 △ △ 3 90.13 -1.39 6.61 △ X Comparative Example 6 0 90.69 -1.33 5.72 ○ △ 1 90.59 -1.32 5.82 △ △ 2 90.45 -1.33 5.89 △ △ 3 90.23 -1.29 5.99 △ △ Comparative Example 7 0 95.71 -1.43 1.71 ◎ ○ 1 94.9 -1.42 1.69 ○ ○ 2 94.7 -1.41 1.66 ○ ○ 3 94.5 -1.4 1.65 ○ △

[0305] Regarding reflectance at 450 nm, Examples 1 to 4 exhibited higher initial reflectance than Comparative Examples 1 to 6, and a similar trend was observed even after three treatments with 500 mJ of UV light. While Examples 1 to 4 exhibited reflectances of 90.2 to 90.6 after three UV treatments, Comparative Examples 1 to 4 exhibited reflectances of 73 to 89.7 after three UV treatments, likely due to worsening yellowing.

[0306] Evaluation Example 4: Test in a chamber with a temperature of 85°C and a humidity of 85% and a reflectivity test in a HS chamber

[0307] Each of the dry films prepared in Examples 2 to 4 and Comparative Example 1 was laminated using a vacuum laminator (CVP-300, Nichigo-Morton Co., Ltd.) at a first chamber temperature of 60°C, a vacuum pressure of 3 hPa, and a vacuum time of 10 seconds, and then pressed under a pressure of 0.2 MPa and a pressing time of 10 seconds to obtain an evaluation substrate.

[0308] The PET film was peeled off and then exposed to 300 mJ / cm² using an integrated photometer. Subsequently, the film was developed with a 1.0% aqueous Na₂CO₃ solution at 30°C for 60 seconds at a spray pressure of 0.2 MPa. The resulting substrate was then cured in a 150°C oven for 60 minutes to obtain a substrate. The resulting substrate was placed in a chamber (HIFLEX, provided by ETAC) at 85°C and 85% humidity for 1000 hours. The reflectivity of the substrate at a wavelength of 450 nm, after 1000 hours in the HS chamber, was measured using a spectrophotometer (CM-2600d, Konica Minolta Sensing Co., Ltd.). The results are shown in Table 7. ◎:90%≤Reflectivity ○:87%≤Reflectivity<90% △:84%≤Reflectivity<87% X: Reflectivity <84%

[0309] Table 7

[0310] Reflectance evaluation after placement in a chamber at 85°C and 85% humidity Example 2 time L a b Average reflectivity 450 nm reflectivity (%) 0 96.48 -0.92 2.33 ◎ ◎ 168 95.93 -0.87 2.01 ◎ ◎ 350 95.84 -0.82 2.15 ◎ ◎ 500 95.44 -0.78 2.4 ◎ ◎ 750 95.12 -0.76 2.58 ◎ ○ 1000 95.05 -0.81 2.93 ○ ○ Example 3 time L a b Average reflectivity 450 nm reflectivity (%) 0 96.68 -0.87 1.91 ◎ ◎ 168 96.43 -0.82 2 ◎ ◎ 350 96.14 -0.77 2.13 ◎ ◎ 500 95.94 -0.73 2.39 ◎ ◎ 750 95.82 -0.71 2.58 ◎ ◎ 1000 95.42 -0.76 2.92 ◎ ○ Example 4 time L a b Average reflectivity 450 nm reflectivity (%) 0 96.75 -0.87 1.94 ◎ ◎ 168 96.66 -0.82 2.04 ◎ ◎ 350 96.16 -0.77 2.16 ◎ ◎ 500 95.84 -0.73 2.52 ◎ ◎ 750 95.03 -0.71 2.78 ◎ ○ 1000 95.01 -0.76 3.1 ○ ○ Comparative Example 1 time L a b Average reflectivity 450 nm reflectivity (%) 0 96.48 -0.87 2.12 ◎ ◎ 168 95.93 -0.82 2.1 ◎ ◎ 350 95.64 -0.77 2.29 ◎ ◎ 500 95.14 -0.73 2.69 ◎ ◎ 750 94.82 -0.71 2.95 ○ ○ 1000 94.75 -0.76 3.3 ○ △

[0311] Even when evaluated for a long time under high temperature and high humidity conditions, Examples 2 to 4 showed a small decrease in reflectance at 450 nm even under high temperature and high humidity conditions.

[0312] After evaluation under high temperature and high humidity conditions, the b values ​​in Examples 2 to 4 were smaller than those in Comparative Example 1. This indicates that under high temperature and high humidity conditions, Examples 2 to 4 experienced less yellowing than Comparative Example 1. Even under high temperature and high humidity conditions, Examples 2 to 4 experienced less yellowing than Comparative Example 1 and are therefore more suitable as materials for backlight units.

[0313] Evaluation Example 5: General Performance Evaluation

[0314] <Manufacturing of Evaluation Substrates>

[0315] Each photosensitive resin composition prepared in the Examples and Comparative Examples was laminated onto a PET film using a vacuum laminator (CVP-300, Nichigo-Morton Co., Ltd.) at a first chamber temperature of 60°C, a vacuum pressure of 3 hPa, and a vacuum time of 10 seconds. Evaluation substrates were then produced by pressing at a pressure of 0.2 MPa and a pressing time of 10 seconds. The PET film was peeled off and then exposed at 300 mJ / cm² using a DI exposure system manufactured by Screen Co., Ltd., with measurements made through an integrated photometer using a Kodak Step Tablet No. 2 (41 steps) with 23 steps as a photomask. Subsequently, the substrates were developed using a 1.0% Na₂CO₃ aqueous solution at 30°C for 60 seconds at a spray pressure of 0.2 MPa and post-cured in an oven at 150°C to produce the substrates.

[0316] <Pencil Hardness>

[0317] For the substrate, a pencil ranging from B to 9H that had been polished so that the tip of the core was flattened was pressed at an angle of about 45° to record the hardness of the pencil without peeling off the coating film.

[0318] <Adhesion>

[0319] Mark a 1 mm (10 × 10) checkerboard grid on a substrate. Apply clear tape completely to the gridboard. While holding one end of the tape at a right angle to the substrate, immediately peel it off. Count the number of unpeeled squares. Use the number of remaining squares as the numerator and the total number of squares (100) as the denominator to record the result.

[0320] PASS: At least 95% of the board squares remain.

[0321] NG: Fewer than 95% of the board squares remain.

[0322] <Glossiness Evaluation>

[0323] The glossiness of the coating surface of the substrate at an angle of 60° was measured using a gloss colorimeter (BYK E-4430).

[0324] <Solder Heat Resistance>

[0325] Immerse the substrate in a 288°C solder bath for 10 seconds. Then, mark a 1 mm (10 × 10) checkerboard grid on the substrate. Apply clear tape completely to the grid. While holding one end of the tape at a right angle to the substrate, immediately peel it off. Check the number of unpeeled squares. Record the result using the number of remaining squares as the numerator and the total number of squares (100) as the denominator. PASS: At least 95% of the board squares remain. NG: Fewer than 95% of the board squares remain.

[0326] Table 8 Assessment Project Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Pencil hardness 7H 7H 7H 7H 7H 7H 6H 6H 7H 6H 6H 6H 3H 7H 3H Adhesion 100 / 100 PASS 100 / 100 PASS 100 / 100 PASS 100 / 100 PASS 100 / 100 PASS 100 / 100 PASS 100 / 100 PASS 100 / 100 PASS 100 / 100 PASS 100 / 100 PASS 100 / 100 PASS 100 / 100 PASS NG 100 / 100 PASS NG Glossiness 89.1 89.5 90.1 89.7 88.9 88.7 73.0 86.3 86.2 85.3 85.7 85.2 72 89.5 50 Solder heat resistance PASS PASS PASS PASS PASS PASS PASS PASS PASS PASS PASS PASS NG PASS NG

[0327] Comparative Example 5 had a low amount of photopolymerization initiator, resulting in incomplete surface curing, and thus exhibited a low pencil hardness of 3H, a significantly reduced gloss of 72, NG adhesion and solder heat resistance, and unfavorable developability. Comparative Example 6 had an excessively high photopolymerization initiator content, resulting in good surface curing to ensure excellent adhesion and solder heat resistance, but poor developability due to increased curability, which may cause problems in SRO formation. Example 7 exhibited improved pencil hardness of up to 6H and significantly improved adhesion and solder heat resistance, and Example 8 exhibited improved pencil hardness of up to 6H and significantly improved adhesion and solder heat resistance.

[0328] Evaluation Example 6: Analysis of Phosphorus Content in Photosensitive Resin Composition

[0329] 1) Accurately weigh 0.1 g of each photosensitive resin composition of Examples 1 to 8 and Comparative Examples 1 to 6 into a beaker, then add 2 mL of nitric acid and heat on a hot plate to react. 2) Temporarily place the sample on a hot plate and cool to room temperature, then add 0.03 mL of hot hydrochloric acid to react. 3) Afterwards, do not allow the nitric acid solution in the sample to completely evaporate, leaving only a small amount. Cool the residue to room temperature and then completely dissolve it in 1 mL of concentrated nitric acid. Completely dissolve the sample and then dilute with ultrapure water. 4) Analyze the phosphorus (P) concentration of the Examples and Comparative Examples using an ICP-OES analysis system (Optima series, manufactured by Perkin Elmer Co., Ltd.) at wavelengths of 213.617 nm and 214.914 nm.

[0330] Table 9 Assessment Project Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Phosphorus (P) content 2900 ppm 3101 ppm 3120 ppm 3103 ppm 3120 ppm 3050 ppm 3200 ppm 3220 ppm 3230 ppm 3195 ppm 3210 ppm 2985 ppm 430 ppm 5500 ppm

[0331] The compositions of Examples 1 to 8 and Comparative Examples 1 to 4 were found to have phosphorus concentrations of approximately 3,000 ppm. Since Comparative Example 5 did not use a phosphorus-containing photopolymerization initiator, its phosphorus content was found to be as low as 430 ppm. The phosphorus content of Comparative Example 6 was found to be 5,500 ppm.

[0332] none

Claims

1. A photosensitive resin composition, comprising: (A) Carboxyl-containing resins that do not contain aromatic rings; (B) Inorganic fillers; (E) a photopolymerization initiator of a compound containing a trimethylbenzoylphosphine oxide group having at least one PO bond, and further comprising: (H) an epoxy resin of bisphenol.

2. The photosensitive resin composition as claimed in claim 1, wherein (E) the photopolymerization initiator of the compound containing a trimethylbenzoylphosphine oxide group having at least one PO bond comprises the *-C(=O)-P(=O)R1-O-*' moiety (wherein, R1 is an alkyl group of 1 to 20 carbon atoms, an alkenyl group of 2 to 20 carbon atoms, an alkynyl group of 2 to 20 carbon atoms, or a cyclic group of 5 to 20 carbon atoms.

3. The photosensitive resin composition as claimed in claim 1, wherein the photopolymerization initiator of (E) a compound containing a trimethylbenzoylphosphine oxide group having at least one PO bond is a polymer containing a trimethylbenzoylphosphine oxide group.

4. The photosensitive resin composition as claimed in claim 3, wherein the polymer containing a trimethylbenzylphosphine oxide group has a weight-average molecular weight (Mn) of 900 g / mol or higher.

5. The photosensitive resin composition as claimed in claim 3, wherein the polymer containing a trimethylbenzoylphosphine oxide group is represented by the following chemical formula 1: <Chemical Formula 1> a = 0 to 100, b = 0 to 100, and c = 0 to 100.

6. The photosensitive resin composition of claim 1, wherein (E) the photopolymerization initiator of the compound containing a trimethylbenzoylphosphine oxide group having at least one PO bond comprises an alkoxy group.

7. The photosensitive resin composition of claim 1, wherein (E) the photopolymerization initiator of the compound containing a trimethylbenzoylphosphine oxide group having at least one PO bond includes ethoxy.

8. The photosensitive resin composition as claimed in claim 1, wherein (E) the photopolymerization initiator of the compound containing a trimethylbenzoylphosphine oxide group having at least one PO bond is represented by the following chemical formula 2: <chemical formula 2>.

9. The photosensitive resin composition as claimed in claim 1, wherein the content of the photopolymerization initiator of the compound containing a trimethylbenzoylphosphine oxide group having at least one PO bond in (E) is from 0.01 wt% to 10 wt% relative to the total weight of the composition.

10. The photosensitive resin composition as claimed in claim 1, wherein (A) is a carboxyl-containing resin without aromatic rings having unsaturated double bonds.

11. The photosensitive resin composition as claimed in claim 1, further comprising (D) a resin containing an aromatic ring.

12. The photosensitive resin composition as claimed in claim 11, wherein (D) the resin containing an aromatic ring is a melamine resin, a silicone resin, or a resin having a styrene backbone.

13. The photosensitive resin composition as claimed in claim 1 further comprises (C) mercapto-modified (meth)acrylate.

14. The photosensitive resin composition as claimed in claim 1 further comprises (F) a silane coupling agent.

15. The photosensitive resin composition of claim 1, further comprising (G) a resin having a carbamate bond.

16. The photosensitive resin composition of claim 1, wherein the photopolymerization initiator of the compound containing a trimethylbenzylphosphine oxide group having at least one PO bond in (E) has an exhalation content of 1000 ppm or less as measured by thermal desorption spectroscopy (TDS) and gas chromatography-mass spectrometry (GC-MS).

17. The photosensitive resin composition as claimed in claim 1, wherein the phosphorus content is from 500 ppm to 5000 ppm.

18. A photosensitive resin composition comprising: (A) Carboxyl-containing resins without aromatic rings; (B) Thiol-modified (meth)acrylates; (E) a photopolymerization initiator of a compound containing a trimethylbenzoylphosphine oxide group having at least one PO bond, and further comprising: (H) an epoxy resin of bisphenol.

19. The photosensitive resin composition of claim 18, further comprising (D) a resin containing an aromatic ring.

20. The photosensitive resin composition as claimed in claim 18 further comprises (F) a silane coupling agent.

21. The photosensitive resin composition of claim 18 further comprises (G) a resin having a carbamate bond.

22. A dry film having a photosensitive resin layer formed by coating a first film with the photosensitive resin composition of any one of claims 1 to 21 and drying it.

23. A cured product obtained by curing the photosensitive resin composition of any one of claims 1 to 21 or a dry film photosensitive resin layer obtained from said photosensitive resin composition.

24. A printed circuit board comprising the cured product of claim 23 as a solder resist.

25. The printed circuit board as claimed in claim 24, further comprising a silicone sealant disposed on the solder resist.

26. The printed circuit board of claim 25, wherein the silicone sealant comprises an upper sealant region and a lower sealant region, and the content of a photopolymerization initiator comprising a compound having at least one PO bond of a trimethylbenzoylphosphine oxide group contained in at least one of the upper sealant regions or the lower sealant region is 1000 ppm or less, relative to the content of the photopolymerization initiator comprising a compound having at least one PO bond of a trimethylbenzoylphosphine oxide group contained in at least one of the upper sealant regions or the lower sealant region.

27. A laminate, comprising: The cured product described in claim 23; and protective film.

28. The laminate as claimed in claim 27, wherein the content of the photopolymerization initiator of the compound containing a trimethylbenzoylphosphine oxide group having at least one PO bond in the protective film is 1000 ppm or less, relative to the content of the photopolymerization initiator of the compound containing a trimethylbenzoylphosphine oxide group having at least one PO bond in the solder resist (E).

Images