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

Abstract

One embodiment of the present invention relates to a photosensitive resin composition comprising (A) a carboxyl group-containing resin not containing an aromatic ring, (B) an inorganic filler, and (E) a photopolymerization initiator that is a trimethylbenzoylphosphine oxide group-containing compound containing one or more P-O bonds. The combination of these four components significantly reduces outgassing of the photopolymerization initiator, thereby improving the yellowing and uncured state of silicone encapsulants and improving the reactivity of silicone encapsulants. Furthermore, the composition can prevent transfer of outgassing of the photopolymerization initiator to the protective film, eliminating the need for a baking process after the reflow process. Furthermore, the composition can improve power consumption by increasing reflectivity. Furthermore, the composition exhibits high HAST resistance and reflectivity after the HAST test, and the decrease in reflectivity under high temperature / high humidity conditions is suppressed. These characteristics enable the photosensitive resin composition of the present invention to exhibit excellent effectiveness as a solder resist. Therefore, the photosensitive resin composition of the present invention can efficiently open many holes in the solder resist, and the solder resist has high reflectivity, making it possible to realize an efficient backlight unit.

Description

[Technical Field]

[0001] The present invention relates to a photosensitive resin composition, a dry film, a cured product, a printed wiring board, and a laminate. In particular, the dry film has a photosensitive resin layer formed by applying the photosensitive resin composition onto a first film and drying it, the cured product is obtained by curing the photosensitive resin layer of the dry film, and the printed wiring board and the laminate include the cured product. [Background technology]

[0002] In general, in printed wiring boards used in electronic devices, etc., a solder resist layer is formed on the board on which the circuit pattern is formed in areas other than the connection holes in order to prevent solder from adhering to unnecessary areas when mounting electronic components on the printed wiring board and to prevent the circuit conductors from being exposed and corroding due to oxidation or humidity.

[0003] In recent years, electronic devices have become lighter, thinner, shorter, and smaller, resulting in higher precision and higher density of printed wiring boards. Currently, solder resist layers are mainly formed by applying a photosensitive resin composition to a substrate, forming a pattern by exposure and development, and then fully curing the patterned resin by heating or light irradiation, which is called a photosolder resist.

[0004] The liquid photosensitive resin composition as described above contains a solvent in the composition, and the steps of printing and drying the composition must be repeated during production, which results in long working times and is not environmentally friendly.

[0005] Therefore, it has been proposed to form a solder resist layer using a so-called photosensitive dry film, which can omit the drying step after applying the composition, instead of a liquid photosensitive resin composition. Laminating using a dry film shortens the working time, greatly shortens the manufacturing process, and is very productive, allowing the efficient use of a solder resist layer even on thin-film substrates.

[0006] Such dry films generally have a laminated structure in which a solder resist layer, a photosensitive resin layer, is formed on a first film substrate, and a second film is bonded to the layer for protection or other purposes. In use, the second film is peeled off, the film is heated and pressed onto a wiring board, and the first film is exposed to light, and then the first film is peeled off and developed to form a patterned solder resist layer. When forming a solder resist layer using a dry film, compared to using a liquid photosensitive resin composition such as the one described above, not only can the drying step of the composition be omitted, but the dry film is pressed onto the circuit board, which reduces the likelihood of air bubbles being trapped between the board and the solder resist layer and improves the ability to fill recesses on the board surface. Furthermore, when forming a solder resist layer using a dry film, the film exhibits excellent flatness, allowing for efficient chip mounting and high resolution.

[0007] However, since a white solder resist layer has a higher reflectivity than a colored solder resist layer, when a solder resist layer is formed using a dry film in the above-mentioned manner, light is reflected from the surface of the solder resist layer during exposure, making it difficult for the light to penetrate to the bottom, resulting in a phenomenon called halation, in which the top of the surface is larger than the bottom, making it difficult to realize a pattern (see, for example, Patent Document 1, etc.).

[0008] On the other hand, since the solder resist layer also functions as a permanent protective film for the circuit board, the solder resist composition is required to have various properties such as alkaline developability and solder heat resistance.

[0009] Furthermore, in addition to the properties required for a general solder resist layer, it is important that the white solder resist layer has high reflectivity, that the reflectivity does not decrease much during the manufacturing process, and that the cured product does not turn yellow even when exposed to heat or light.

[0010] There is a need for a photosensitive resin composition that satisfies the basic properties required for a solder resist layer as well as the additional properties required for a white solder resist layer, has a higher reflectance than conventional ones, and is excellent in yellowing resistance, and for a method for producing a dry film and a printed wiring board that include a solder resist layer, which can solve the specific problems that arise in the manufacturing process of the solder resist layer. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Detailed Description of the Invention of Korean Patent Publication No. 10-2022-0086524

[0012] [Technical issues] Conventionally, photopolymerization initiators (e.g., 2,4,6-trimethylbenzoyldiphenyl phosphine oxide (TPO)) contained in photosensitive resin compositions used to form solder resists generate a large amount of outgassing. When this outgas spreads to the adjacent silicone encapsulant, the transparent silicone encapsulant turns yellow, reducing its reflectance and making it difficult for the silicone encapsulant to harden. These problems have led to concerns about the long-term reliability of the substrate. Furthermore, the photopolymerization initiator can be transferred to the adjacent substrate in addition to the silicone encapsulant.

[0013] Therefore, in order to remove outgassing from the photopolymerization initiator, it has been considered to add a baking process (e.g., curing at 150°C for 6 hours) after the reflow process (e.g., 10 seconds at 260°C), but this baking process significantly reduces the reflectivity, and when used in a backlight unit, etc., there is a problem that power consumption increases to increase the reflectivity after the chip is mounted. In other words, the number of processes increases, but the reflectivity also decreases.

[0014] Furthermore, before the baking process, a protective film (PF) can be placed on the solder resist layer to remove the photopolymerization initiator. The protective film is a film used to minimize outgassing of the photopolymerization initiator after the solder resist is prepared and before the subsequent baking process. It is peeled off and removed before the baking process, and because it has high affinity with the photopolymerization initiator, it can efficiently remove the photopolymerization initiator, so it was used for the purpose of removing the photopolymerization initiator. However, in the end, two additional processes, the use of the protective film and the baking process, are required, and the problem of reduced reflectivity still exists.

[0015] The present invention has been made to solve the above-mentioned problems, and provides a technology for a photosensitive resin composition comprising (A) a carboxyl group-containing resin not containing an aromatic ring, (B) an inorganic filler or (C) a mercapto-modified (meth)acrylate, and (E) a photopolymerization initiator which is a trimethylbenzoylphosphine oxide group-containing compound having one or more P-O bonds.

[0016] The photosensitive resin composition of the present invention significantly reduces outgassing of the photopolymerization initiator, thereby alleviating problems such as yellowing and uncured silicone encapsulants and improving the reactivity of the silicone encapsulant. Furthermore, by suppressing the amount of outgassing generated by the photopolymerization initiator, the amount of outgas transferred to the protective film can be reduced, making it possible to omit a baking process after the reflow process. Furthermore, the increased reflectance can alleviate problems with power consumption. Furthermore, the photosensitive resin composition of the present invention exhibits high reflectance and excellent HAST resistance after reflow, UV testing, or HAST testing, and can suppress a decrease in reflectance under high temperature / high humidity conditions. Due to these characteristics, solder resists produced using the photosensitive resin composition of the present invention exhibit excellent effects.

[0017] The present invention also provides a dry film, a cured product, a printed wiring board, and a laminate using the photosensitive resin composition. [Technical solution]

[0018] One embodiment of the present invention relates to a photosensitive resin composition.

[0019] In one aspect, the photosensitive resin composition may include (A) a carboxyl group-containing resin that does not contain an aromatic ring, (B) an inorganic filler, and (E) a photopolymerization initiator that is a trimethylbenzoylphosphine oxide group-containing compound that has one or more P-O bonds.

[0020] In one aspect, the (E) photopolymerization initiator that is a trimethylbenzoylphosphine oxide group-containing compound having one or more P-O bonds may include a *-C(=O)-P(=O)R1-O-*' moiety (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 one aspect, the (E) photopolymerization initiator which is a trimethylbenzoylphosphine oxide group-containing compound containing one or more P-O bonds may be a trimethylbenzoylphosphine oxide group-containing polymer.

[0022] In one aspect, the trimethylbenzoylphosphine oxide group-containing polymer may have a weight average molecular weight (Mn) of 900 g / mol or more.

[0023] In one aspect, the trimethylbenzoylphosphine oxide group-containing polymer may be represented by the following Chemical Formula 1:

[0024] [ka] a=0~100, b=0~100, c=0~100

[0025] In one aspect, the (E) photopolymerization initiator, which is a trimethylbenzoylphosphine oxide group-containing compound containing one or more P-O bonds, may contain an alkoxy group.

[0026] In one aspect, the (E) photopolymerization initiator, which is a trimethylbenzoylphosphine oxide group-containing compound containing one or more PO bonds, may contain an ethoxy group.

[0027] In one aspect, the (E) photopolymerization initiator, which is a trimethylbenzoylphosphine oxide group-containing compound having one or more P-O bonds, may be represented by the following Chemical Formula 2:

[0028] [ka]

[0029] In one aspect, the content of the (E) photopolymerization initiator which is a trimethylbenzoylphosphine oxide group-containing compound having one or more PO bonds may be 0.01 to 10 wt % based on the total weight of the composition.

[0030] In one aspect, the (A) carboxyl group-containing resin not containing an aromatic ring may contain an unsaturated double bond.

[0031] In one aspect, the photosensitive resin composition may further include (D) a resin containing an aromatic ring.

[0032] In one aspect, the (D) resin containing an aromatic ring may be a melamine resin, a silicone resin, or a resin having a styrene skeleton.

[0033] In one aspect, the photosensitive resin composition may further include (C) a mercapto-modified (meth)acrylate.

[0034] In one aspect, the photosensitive resin composition may further include (F) a silane coupling agent.

[0035] In one aspect, the photosensitive resin composition may further include (G) a resin having a urethane bond.

[0036] In one aspect, the outgassing content of the photosensitive resin composition measured by thermal desorption spectroscopy (TDS) and gas chromatography-mass spectrometry (GC-MS) may be 1,000 ppm or less relative to the content of (E) the photopolymerization initiator, which is a trimethylbenzoylphosphine oxide group-containing compound having one or more P-O bonds.

[0037] In one aspect, the photosensitive resin composition may have a phosphorus content of 500 to 5000 ppm.

[0038] Another embodiment of the present invention relates to a photosensitive resin composition comprising (A) a carboxyl group-containing resin that does not contain an aromatic ring, (C) a mercapto-modified (meth)acrylate, and (E) a photopolymerization initiator that is a trimethylbenzoylphosphine oxide group-containing compound that has one or more P-O bonds.

[0039] In one aspect, the photosensitive resin composition may further include (D) a resin containing an aromatic ring.

[0040] In one aspect, the photosensitive resin composition may further include (F) a silane coupling agent.

[0041] In one aspect, the photosensitive resin composition may further include (G) a resin having a urethane bond.

[0042] Another embodiment of the present invention relates to a dry film having a photosensitive resin layer formed by coating the above-mentioned photosensitive resin composition on a first film and drying the coated film.

[0043] Another embodiment of the present invention relates to a cured product obtained by curing the above-mentioned photosensitive resin composition or the photosensitive resin layer of a dry film obtained from the same.

[0044] Another embodiment of the present invention relates to a printed wiring board containing the above-described cured product as a solder resist.

[0045] In one aspect, the printed wiring board may further include a silicon encapsulant layer disposed on the solder resist.

[0046] In one aspect, the silicon encapsulant layer includes an upper encapsulant region and a lower encapsulant region, and the content of the (E) photopolymerization initiator contained in at least one of the upper encapsulant region or the lower encapsulant region may be 1,000 ppm or less relative to the content of the (E) photopolymerization initiator contained in the solder resist.

[0047] Yet another embodiment of the present invention relates to a laminate including the above-described cured product and a protective film.

[0048] In one aspect, the content of the (E) photopolymerization initiator contained in the protective film may be 1,000 ppm or less relative to the content of the (E) photopolymerization initiator contained in the solder resist. [Effects of the invention]

[0049] The photosensitive resin composition according to one embodiment of the present invention significantly reduces outgassing of the photopolymerization initiator, thereby alleviating problems such as yellowing and uncured silicone encapsulants and improving the reactivity of the silicone encapsulant. Furthermore, the amount of outgassing of the photopolymerization initiator transferred to the protective film can be reduced, making it possible to omit the baking process after the reflow process, and the increased reflectance can alleviate problems with power consumption. Furthermore, the composition exhibits high HAST resistance and reflectance after the HAST test, and the decrease in reflectance under high temperature / high humidity conditions can be suppressed. Due to these characteristics, the solder resist produced using the photosensitive resin composition of the present invention can exhibit excellent effects.

[0050] For example, the photosensitive resin composition according to one aspect of the present invention may further contain titanium oxide as an inorganic filler, thereby achieving excellent reflectance maintenance effect.

[0051] The present invention also provides a dry film, a cured product, and a printed wiring board using the photosensitive resin composition. [Brief explanation of the drawings]

[0052] 1A and 1B are images showing the results of the BHAST test of dry films using the photosensitive resin compositions of Comparative Example 1 and Example 3, respectively.

[0053] Various embodiments of the present invention will now be described.

[0054] [Photosensitive resin composition]

[0055] One embodiment of the present invention relates to a photosensitive resin composition comprising (A) a carboxyl group-containing resin that does not contain an aromatic ring, (B) an inorganic filler, and (E) one or more photopolymerization initiators selected from the group consisting of trimethylbenzoylphosphine oxide group-containing compounds having one or more P-O bonds.

[0056] Another embodiment of the present invention relates to a photosensitive resin composition comprising (A) a carboxyl group-containing resin that does not contain an aromatic ring, (C) a mercapto-modified (meth)acrylate, and (E) a photopolymerization initiator that is a trimethylbenzoylphosphine oxide group-containing compound that has one or more P-O bonds.

[0057] The photosensitive resin composition can suppress outgassing and exhibit excellent reactivity with silicone encapsulants, reflectance, and HAST resistance.

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

[0059] Each component of the photosensitive resin composition will be described in detail below.

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

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

[0062] Resin (A) contains carboxyl groups, allowing for alkaline development. Its absence of aromatic rings provides excellent resistance to discoloration and yellowing when exposed to heat or UV energy. Furthermore, the combination with inorganic filler (B), described below, allows for high reflectance, resulting in minimal reflectance loss after the reflow process and a 3,000-hour blue light test. Therefore, compositions containing resin (A) exhibit less reflectance loss due to discoloration and yellowing than other white ink compositions, providing excellent yellowing resistance. For example, carboxyl-containing resins containing aromatic rings exhibit relatively lower initial reflectance in cured products than resin (A) without aromatic rings, and can experience significant reflectance loss when subjected to heat, UV, BHAST, and 85°C / 85% tests. This is due to the aromatic rings being deformed by heat, UV, BHAST, and 85°C / 85% tests, significantly impacting the reflectance loss.

[0063] For example, the resin (A) may contain an unsaturated double bond. When the resin (A) contains an unsaturated double bond, it can be radically cured by ultraviolet light, electron beams, or heat.

[0064] The resin (A) is not particularly limited as long as it does not contain an aromatic ring and contains a carboxyl group, but may be, for example, a photosensitive carboxyl group-containing resin that itself has one or more photosensitive unsaturated double bonds, or a carboxyl group-containing resin that does not have a photosensitive unsaturated double bond.

[0065] For example, the resin (A) may be any of the following resins that do not have an aromatic ring (either an oligomer or a polymer is possible):

[0066] (1) a carboxyl group-containing resin obtained by copolymerizing an unsaturated carboxylic acid and a compound having an unsaturated double bond;

[0067] (2) A photosensitive carboxyl group-containing resin obtained by reacting a carboxyl group-containing (meth)acrylic copolymer resin with a compound having an oxirane ring and an ethylenically unsaturated group in one molecule.

[0068] (3) A photosensitive carboxyl group-containing resin obtained by reacting a copolymer of a compound having one epoxy group and one unsaturated double bond per molecule with an unsaturated monocarboxylic acid, and then reacting the resulting copolymer with a secondary hydroxyl group-saturated or unsaturated polybasic acid anhydride.

[0069] (4) A photosensitive resin containing hydroxyl and carboxyl groups, obtained by reacting a hydroxyl-containing polymer with a saturated or unsaturated polybasic acid anhydride, followed by a compound having one epoxy group and one unsaturated double bond in each molecule of the carboxylic acid produced by this reaction.

[0070] For example, the resin (A) may be (a) a carboxyl group-containing (meth)acrylic copolymer resin, which is a photosensitive resin containing a carboxyl group (2), and (b) a copolymer resin having a carboxyl group obtained by reacting a compound having an oxirane ring and an ethylenically unsaturated group in one molecule.

[0071] For example, (a) a carboxyl group-containing (meth)acrylic copolymer resin can be obtained by copolymerizing a (meth)acrylic acid ester and a compound having one unsaturated group and at least one carboxyl group in one molecule, but is not limited to this. Examples of the (meth)acrylic acid ester constituting the copolymer resin (a) include (meth)acrylic acid alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, and hexyl (meth)acrylate; hydroxyl group-containing (meth)acrylic acid esters such as 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, and caprolactone-modified 2-hydroxyethyl (meth)acrylate; and glycol-modified (meth)acrylates such as methoxydiethylene glycol (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. In this specification, (meth)acrylate is a general term for acrylate and methacrylate, and the same applies to other similar expressions.

[0072] Examples of compounds having one unsaturated group and at least one carboxyl group in one molecule include acrylic acid, methacrylic acid, modified unsaturated monocarboxylic acids in which a chain is extended between the unsaturated group and the carboxylic acid, such as β-carboxyethyl (meth)acrylate, 2-acryloyloxyethyl succinic acid, 2-acryloyloxyethyl hexahydrophthalic acid, unsaturated monocarboxylic acids having an ester bond due to lactone modification, modified unsaturated monocarboxylic acids having an ether bond, and those containing two or more carboxyl groups in the molecule, such as maleic acid. These may be used alone or in combination of two or more.

[0073] (b) Compounds having an oxirane ring and an ethylenically unsaturated group in one molecule may be any compounds having an oxirane ring and an ethylenically unsaturated group in one molecule, such as 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 may be used alone or in combination of two or more. For example, (b) Compounds having an oxirane ring and an ethylenically unsaturated group in one molecule may be 3,4-epoxycyclohexylmethyl (meth)acrylate.

[0074] For example, the resin (A) may have an acid value of 30 to 200 mg KOH / g. When the acid value of the resin (A) is 30 mg KOH / g or more, the unexposed portions of the solder resist composition coating film can be easily removed with a weak alkaline aqueous solution. When the acid value of the resin (A) is 200 mg KOH / g or less, the water resistance and electrical properties of the cured film can be improved.

[0075] For example, the weight-average molecular weight of resin (A) may be 5,000 to 100,000 g / mol. When the weight-average molecular weight of resin (A) is 5,000 g / mol or more, it is possible to prevent a decrease in the tackiness of the solder resist composition coating film. When the weight-average molecular weight of resin (A) is 100,000 g / mol or less, it is possible to prevent a decrease in the developability and storage stability of the solder resist composition.

[0076] In the photosensitive resin composition of the present invention, the content of resin (A) may be 5 to 40 wt%, 10 to 35 wt%, or 12 to 33 wt% of the total composition. The composition contains a solid content and a solvent. The content of resin (A) may be calculated on a solid content basis.

[0077] When the content of resin (A) is within the above range, excellent yellowing resistance and high reflectance can be realized, a solder resist coating film can be formed well, excellent pencil hardness and adhesion can be exhibited, and deterioration of the tack-free property and undercut of the coating film can be suppressed.

[0078] [(B) Inorganic filler]

[0079] The photosensitive resin composition according to one embodiment of the present invention can obtain high reflectance by including an inorganic filler.

[0080] Examples of inorganic fillers include titanium oxide, zinc oxide, basic carbonates, basic sulfates, sulfates, zinc sulfide, antimony oxide, aluminum hydroxide, silica, and barium sulfate. For example, when a composition is formulated using a mixture of barium sulfate and silica as the 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 may be measured according to Hunter 1948. For example, when a composition is formulated using a high content of titanium oxide and silica as the 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, resulting in high whiteness and reflectance. For example, when a composition is formulated using at least one of titanium oxide and silica as the inorganic filler, the L value may be 95 or greater, an a value of -2 or greater, and a b value of -1 or greater, resulting in the highest whiteness and reflectance.

[0081] For example, the method for producing titanium oxide may be either a sulfuric acid method or a chlorine method, for example, a chlorine method. For example, sulfuric acid may not be used in the production process. Furthermore, the surface treatment of titanium oxide is not particularly limited, but titanium oxide may be treated with an acid other than sulfuric acid, such as hydrochloric acid, nitric acid, phosphoric acid, or acetic acid, during neutralization.

[0082] The titanium oxide may be of any structure selected from the group consisting of rutile, anatase, and ramsdellite types, and may be used alone or in combination of two or more. Among these, ramsdellite titanium oxide is ramsdellite Li 0.5 TiO2 can be obtained by chemical lithium oxide desorption treatment.

[0083] Among these, the use of rutile titanium oxide can further improve heat resistance, reduce discoloration due to light exposure, and reduce deterioration in quality even in harsh operating environments. In particular, the use of rutile titanium oxide surface-treated with aluminum oxide such as alumina can improve heat resistance. The content of rutile titanium oxide surface-treated with aluminum oxide in the total titanium oxide is, for example, 35% by mass or more, e.g., 55% by mass or more, with the upper limit being 100% by mass or less, i.e., the entire amount of titanium oxide may be rutile titanium oxide surface-treated with aluminum oxide. Furthermore, anatase titanium oxide has a lower hardness than rutile titanium oxide, and therefore, the use of anatase titanium oxide is more useful in terms of the formability of the composition.

[0084] In the photosensitive resin composition of the present invention, the blending amount of the (B) inorganic filler may be in the range of 30 to 70 mass % of the total resin composition, for example, in the range of 40 to 70 mass %, for example, in the range of 45 to 70 mass %. The content of the (B) inorganic filler may be calculated on a solid content basis. If the content of the (B) inorganic filler is within the above range, it is advantageous for high reflectivity, if it is less than the above range, the reflectivity will decrease, and if it exceeds the above range, cracks may occur.

[0085] Among the (B) inorganic fillers, titanium oxide may have 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. Alternatively, commercially available titanium oxide with a sulfur concentration of 100 ppm or more may be blended after lowering the sulfur concentration by heat treatment, chemical treatment, or purification such as washing or calcination. Here, sulfur contained in titanium oxide refers to all sulfur detected by analysis. This includes sulfur adsorbed on titanium oxide and sulfur applied to titanium oxide as an impurity. Furthermore, titanium oxide may have a sodium concentration of 100 ppm or less, or 50 ppm or less. The lower the sodium concentration, the better. If the sodium concentration is too high, sodium ions may promote corrosion and oxidation of the copper substrate when exposed to moisture. For this reason, the sodium ion concentration may be 100 ppm or less.

[0086] The photosensitive resin composition of the present invention may contain titanium oxide having a sulfur concentration of 100 ppm or more, provided that the effect of the present invention is 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 Industries Co., Ltd., and R-21 manufactured by Sakai-Chem Co., Ltd.

[0087] Other examples that can be used include rutile-type chlorine-process titanium oxides such as T-550, T-580, R-630, R-820, CR-50, CR-60, R-90, and CR-97 manufactured by Ishihara Sangyo Co., Ltd., Ti PURE R-706, R-902+, and R931 manufactured by DuPont, TR-600, TR-700, and TR-840 manufactured by Fuji Titanium Industrial Co., Ltd., and KR-270, KR-310, and KR-380 manufactured by Titanium Industrial Co., Ltd.

[0088] If the particle size of titanium oxide is too small, the flowability will be poor, and conversely, if it is too large, the insertability into a small diameter substrate may be poor. From these points of view, the median particle size of titanium oxide is in the range of 0.1 to 5 μm, for example, in the range of 0.1 to 1 μm, for example, in the range of 0.1 to 0.5 μm, and may be 0.36 μm. If the particle size of titanium oxide is within the above range, high reflectivity can be achieved. The above particle size was measured using a laser diffraction method.

[0089] Among the inorganic fillers (B), examples of barium sulfate 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, BARIACE BF-10, BARIACE BF-20, BARIACE BF-40 (manufactured by Sakai Chemical Industry Co., Ltd.), W-1, W-6, W-10, and C300 (manufactured by Takehara Kagaku Kogyo Co., Ltd.).

[0090] Among the (B) inorganic fillers, silica particles are not particularly limited and may be obtained by methods known to those of ordinary skill in the art. For example, they can be produced by burning silicon powder using the VMC (Vaporized Metal Combustion) method. The VMC method involves forming a chemical flame using a burner in an oxygen-containing atmosphere, adding a metal powder that constitutes part of the desired oxide particles into this chemical flame in an amount sufficient to form a dust cloud, and producing oxide particles by knocking. Commercially available silicas include the SO series manufactured by Admatechs Co., Ltd. and the HPS series manufactured by Towa Gosei Co., Ltd. (HPS-0500, HPS-1000, HPS3500, etc.).

[0091] [(C) Mercapto-modified (meth)acrylate]

[0092] The photosensitive resin composition according to one embodiment of the present invention may have enhanced surface hardening, improved gloss, and high reflectivity due to the use of (C) mercapto-modified (meth)acrylate.

[0093] In addition, when the (C) mercapto-modified (meth)acrylate of the present invention is used in a photosensitive resin composition together with the (B) inorganic filler, the surface hardening of the photosensitive resin layer is improved, and the improved surface hardening may enable the realization of higher reflectivity and higher gloss.

[0094] The (C) mercapto-modified (meth)acrylate of the present invention is a compound modified by introducing a mercapto group into an acrylate compound, and the acrylate compound may be a mono- or polyfunctional acrylate compound, and may be an aliphatic compound having 1 to 15 carbon atoms and substituted with one or more functional groups selected from the group consisting of an acryloyl group, an acryloyloxy group, and an acryloyloxyalkyl group, such as pentane triacrylate.

[0095] The (C) mercapto-modified (meth)acrylate of the present invention may be curable or may be actinic ray-curable. The (C) mercapto-modified (meth)acrylate of the present invention is a mercapto-modified (meth)acrylate, and can be obtained by subjecting a polyfunctional thiol compound and a stoichiometrically excessive amount of a difunctional or higher polyfunctional (meth)acrylate compound to a Michael addition reaction. Examples of the polyfunctional thiol compound include a polyfunctional thiol compound that is a reaction product of a polyisocyanate 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)benzenetetrathiol with a polyfunctional thiol compound such as trimethylolpropane tris(3-mercaptopropionate); and a reaction product of a polyisocyanate such as isophorone diisocyanate with a polyfunctional thiol compound such as trimethylolpropane tris(3-mercaptopropionate). Examples of suitable mercapto-modified (meth)acrylates include polyfunctional thiol compounds, such as reaction products of polyisocyanates (e.g., hexamethylene diisocyanate) with polyfunctional thiol compounds (e.g., 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), trimethylolpropane tris(2-mercaptoacetate), and ethylene glycol bis(3-mercaptopropionate) (molecular weight 238 g / mol). For example, the mercapto-modified (meth)acrylate (C) may contain two or more mercapto groups, or may contain three or more mercapto groups.

[0096] The weight-average molecular weight of the (C) mercapto-modified (meth)acrylate may be 5,000 g / mol or less, 3,000 g / mol or less, or 2,000 g / mol or less. A weight-average molecular weight of 5,000 g / mol or less reduces the mobility of the mercapto-modified (meth)acrylate molecules, thereby suppressing a decrease in reactivity during the formation of the active energy ray-curable coating film of the present invention. For example, a decrease in reactivity can increase the tackiness of the cured coating film surface when the coating film is cured with UV-LED, increasing the likelihood of the printed material becoming sticky when placed on it.

[0097] In the photosensitive resin composition of the present invention, the content of the (C) mercapto-modified (meth)acrylate may be 1 to 20 parts by weight, 1 to 10 parts by weight, or 1 to 7 parts by weight, relative to 100 parts by weight of the total composition.

[0098] If the content of (C) mercapto-modified (meth)acrylate is within the above range, the surface curing is strengthened, gloss is improved, high reflectance is possible, and even after the manufacturing process, the reflectance decreases little, and excellent crack resistance can be achieved. In addition, the decrease in gloss due to the decrease in surface curing can be suppressed, high reflectance can be achieved, and the surface can be appropriately cured, reducing cracking of the coating film and improving resolution.

[0099] [(D) Resin containing an aromatic ring]

[0100] The photosensitive resin composition of the present invention contains (A) a carboxyl group-containing resin (A) that does not contain an aromatic ring, and may further contain (D) a resin that contains an aromatic ring in addition to the (A) resin.

[0101] The aromatic ring-containing resin (D) can exhibit excellent yellowing resistance when combined with the aromatic ring-containing resin (A). The photosensitive resin composition according to one embodiment of the present invention can exhibit excellent yellowing resistance by containing the aromatic ring-containing resin (D) in a smaller amount than the aromatic ring-containing resin (A).

[0102] The (D) aromatic ring-containing resin of the present invention may be, for example, a resin that is cured by heating to exhibit electrical insulation properties.

[0103] The aromatic ring may be a benzene ring, a pyridine ring, a pyrimidine ring, a triazine ring, or the like. Examples of the resin (D) containing an aromatic ring of the present invention that can be used include melamine resins, silicone resins, and resins having a styrene skeleton, and for example, a resin having a styrene skeleton can be used.

[0104] The (D) aromatic ring-containing resin may contain a carboxyl group, for example, a carboxyl group-containing resin having a styrene skeleton. For example, the (D) aromatic ring-containing resin may be a mixture of a carboxyl group-containing resin having a styrene skeleton and a carboxyl group-containing resin other than the carboxyl group-containing resin having a styrene skeleton.

[0105] For example, if the (D) aromatic ring-containing resin is a carboxyl group-containing resin having a styrene skeleton, it may not have a photosensitive group such as an ethylenically unsaturated bond having a carboxyl group in the molecule, but may have a styrene skeleton in the molecule, an average molecular weight of 10,000 to 50,000 g / mol, and an acid value of 80 to 200 mg KOH / g. Such a carboxyl group-containing resin having a styrene skeleton can be synthesized by copolymerizing styrene as an essential monomer. By using a carboxyl group-containing resin having physical properties within the above-mentioned ranges, it is possible to achieve excellent dryness to touch and anti-running effects in the cured film.

[0106] Examples of carboxyl group-containing resins having a styrene skeleton include carboxyl group-containing resins (either oligomers or polymers) obtained by copolymerizing an unsaturated carboxylic acid such as (meth)acrylic acid with a compound containing an unsaturated group selected from styrene, α-methylstyrene, lower alkyl (meth)acrylate, isobutylene, etc. Here, the lower alkyl can mean an alkyl group having 1 to 5 carbon atoms.

[0107] In the photosensitive resin composition of the present invention, the weight-average molecular weight of the carboxyl group-containing resin having a styrene skeleton varies depending on the resin skeleton, but may 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. By setting the weight-average molecular weight at 10,000 g / mol or more, not only is the effect of preventing runaway improved, but also the dryness to the touch (tackiness) is further improved, the moisture resistance of the exposed coating film is improved, and film thinning during development is suppressed, thereby suppressing a decrease in resolution. Furthermore, by setting the weight-average molecular weight at 50,000 g / mol or less, not only is the effect of preventing runaway improved, but developability and storage stability can also be improved.

[0108] In the photosensitive resin composition of the present invention, the acid value of the carboxyl group-containing resin having a styrene skeleton may be 80 to 200 mg KOH / g, or 100 to 180 mg KOH / g. By making the acid value of the carboxyl group-containing resin having a styrene skeleton 80 mg KOH / g or more, the softening point is increased, thereby improving tackiness and developability. On the other hand, by making the acid value of the carboxyl group-containing resin having a styrene skeleton 200 mg KOH / g or less, stress is not generated during curing due to an appropriate crosslink density, and a good coating film can be obtained.

[0109] In the photosensitive resin composition of the present invention, the carboxyl group-containing resin having a styrene skeleton has an aromatic ring, and thus, despite having an aromatic ring, the cured product is prevented from decreasing in reflectance and discoloration due to light irradiation or heat, and has excellent developability and dryness to the touch. The proportion of the styrene skeleton in the molecule may be 10 to 80 mol%, 10 to 60 mol%, or 10 to 50 mol%. That is, when synthesizing the carboxyl group-containing resin having a styrene skeleton, 30 to 60 mol% of styrene can be used relative to the total amount of monomers. When the proportion of the styrene skeleton in the carboxyl group-containing resin having a styrene skeleton is 10 mol% or more in the molecule, compatibility with other components is improved, and when it is 80 mol% or less in the molecule, developability can be improved.

[0110] Carboxyl group-containing resins having a styrene skeleton produced by suspension polymerization can be high-molecular-weight resins. As a result, photosensitive resin compositions using such resins can have excellent dry-to-touch properties (tackiness). Generally, carboxyl group-containing resins having a styrene skeleton produced by suspension polymerization have high molecular weights. However, taking into consideration properties such as screen printing suitability, dry-to-touch properties, and developability, the weight-average molecular weight may be limited to a range of 10,000 to 50,000 g / mol. Therefore, to control the molecular weight, a chain transfer agent can be used during the synthesis of the carboxyl group-containing resin having a styrene skeleton.

[0111] To promote polymerization, a polymerization initiator can be used during synthesis of the carboxyl group-containing resin having a styrene skeleton. Examples of the polymerization initiator include BPO (benzoyl peroxide), t-butylperoxy-2-ethylhexanoate, and AMBN (2,2'-azobis(2-methylbutyronitrile)). For example, BPO (benzoyl peroxide) may be used. The amount of the polymerization initiator may be 0.1 to 10 wt % or 0.1 to 6 wt % in terms of solid content, based on 100 wt % of the carboxyl group-containing resin having a styrene skeleton.

[0112] In the photosensitive resin composition of the present invention, the content of the aromatic ring-containing resin (D) may be 0.1 to 15 wt %, 1 to 10 wt %, or 2 to 6 wt %, based on the total weight of the composition. The photosensitive resin composition contains a solid content and a solvent.

[0113] If the content of the (D) aromatic ring-containing resin is within the above range, a decrease in reflectance and discoloration are suppressed, the developability and dryness to touch are excellent, and the effects of improving reflectance and preventing yellowing can be improved.

[0114] [(E) Photopolymerization initiator]

[0115] The photosensitive resin composition according to one embodiment of the present invention may contain (E) a photopolymerization initiator (hereinafter referred to as "photopolymerization initiator (E)") which is a trimethylbenzoylphosphine oxide group-containing compound having one or more P-O bonds.

[0116] 2,4,6-trimethylbenzoyldiphenylphosphine oxide (TPO), which has been widely used as a conventional photopolymerization initiator, generates a large amount of outgas during the curing process, and this outgas diffuses into the silicone encapsulant layer and protective film, causing yellowing of the silicone encapsulant, reducing reflectivity, and making it difficult to cure, which has caused problems with the long-term reliability of the product.

[0117] The trimethylbenzoylphosphine oxide group-containing polymer used as a photopolymerization initiator has a high molecular weight and therefore generates little outgassing due to heat even in the final curing step where heat is applied, or in the reflow and baking steps.

[0118] On the other hand, even in the case of a trimethylbenzoylphosphine oxide group-containing compound having a lower molecular weight than TPO, it is presumed that the intermolecular bonding strength is improved (for example, stronger hydrogen bonds with OH groups or COOH groups that remain unreacted in the composition) by including one or more P-O bonds, thereby significantly suppressing outgassing of the photopolymerization initiator.

[0119] For example, the trimethylbenzoylphosphine oxide group-containing compound may contain three or more hydrogen-bonding sites, which improves the intermolecular bonding strength and significantly suppresses outgassing of the photopolymerization initiator.

[0120] This can improve the problems of yellowing and non-curing of the silicone encapsulant, reduce the amount of outgassing of the photopolymerization initiator transferred to the protective film, and greatly increase the reaction rate of the silicone encapsulant.

[0121] In addition, when using a photopolymerization initiator such as TPO, a separate baking process (for example, curing at 150°C for 6 hours) was added after the reflow process to efficiently remove the resulting outgassing. However, this baking process significantly reduces reflectivity and increases power consumption when the chip is mounted.

[0122] However, by using the photopolymerization initiator (E) of the present invention, the baking process can be omitted, reducing working time and thereby increasing yield and cost, the reflectance can be increased, power consumption due to a decrease in reflectance can be prevented, the outgassing content of the photopolymerization initiator is very low even without using a protective film for removing the photopolymerization initiator, the degree of cure of the silicone is greatly increased, long-term reliability is improved, and excellent HAST resistance and reflectance after the HAST test can be exhibited. In addition, the decrease in reflectance under high temperature / high humidity conditions can be suppressed.

[0123] The photopolymerization initiator (E) may be liquid at room temperature (20° C.) and 1 atmosphere.

[0124] The photopolymerization initiator (E) may contain a PO bond.

[0125] The photopolymerization initiator (E) may contain a *-C(=O)-P(=O)R1-O-*' moiety (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).

[0126] When the photopolymerization initiator (E) is a trimethylbenzoylphosphine oxide group-containing polymer, the trimethylbenzoylphosphine oxide group-containing polymer has a weight average molecular weight (M n For example, the trimethylbenzoylphosphine oxide group-containing polymer may have a weight average molecular weight (M n ) may be 1,000 g / mol to 100,000 g / mol.

[0127] The trimethylbenzoylphosphine oxide group-containing polymer may be represented by the following Chemical Formula 1:

[0128] [ka] a=0~100, b=0~100, c=0~100

[0129] When the photopolymerization initiator (E) is a trimethylbenzoylphosphine oxide group-containing compound containing a PO bond, the trimethylbenzoylphosphine oxide group-containing compound containing a PO bond may contain an alkoxy group.

[0130] For example, in the above chemical formula 1, a+b+c>0 may be satisfied.

[0131] For example, the trimethylbenzoylphosphine oxide group-containing compound containing the PO bond may contain an ethoxy group.

[0132] The trimethylbenzoylphosphine oxide group-containing compound having the PO bond may be represented by the following Chemical Formula 2.

[0133] [ka]

[0134] For example, the photopolymerization initiator (E) may further include one or more selected from the group consisting of benzoin and its alkyl ethers, acetophenones, anthraquinones, thioxanthones, ketals, benzophenones, α-aminoacetophenones, acylphosphine oxides, acylphosphinates, and oxime esters.

[0135] In the photosensitive resin composition of the present invention, the content of the photopolymerization initiator (E) may be 0.01 to 10 wt %, 0.01 to 7 wt %, or 0.01 to 5 wt % of the total composition. By including the photopolymerization initiator (E) in this range, photocurability on copper is sufficient, the curing properties of the coating film are good, and coating film properties such as chemical resistance are improved, and deep curing properties can also be improved.

[0136] In addition, when the content of the photopolymerization initiator (E) is within the above range, the undercut is not severe and the halation is not significant, so that the resolution is excellent, and many solder resist openings can be formed, and high reflectivity can be maintained.

[0137] [(F) Silane coupling agent]

[0138] The photosensitive resin composition according to one embodiment of the present invention may further contain a silane coupling agent (F). By containing the silane coupling agent (F), the photosensitive resin composition can exhibit the effects of improved crack resistance, improved reflectance compared to conventional compositions, and excellent gloss.

[0139] The silane coupling agent (F) of the present invention may have an organic group such as a vinyl group, a styryl group, an acrylic group, a methacrylic group, an isocyanurate group, an acid anhydride group, a ureido group, an epoxy group, an amino group, a methacryloxy group, a mercapto group, or an isocyanate group.

[0140] Examples of silane coupling agents having a vinyl group include vinyltrimethoxysilane and vinyltriethoxysilane. Examples of silane coupling agents having a styryl group include p-styrylmethoxysilane. Examples of silane coupling agents having a methacryl group include 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyldiethoxysilane, and 3-methacryloxypropyltriethoxysilane. Examples of silane coupling agents having an acrylic group include 3-acryloxypropyltrimethoxysilane. Examples of silane coupling agents having an amino group include N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, and N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane. Examples of silane coupling agents having a methacryloxy group include 3-methacryloxypropyltrimethoxysilane and 3-methacryloxypropyltriethoxysilane. Examples of silane coupling agents having a mercapto group include 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane. Examples of silane coupling agents having an isocyanate group include 3-isocyanatepropyltriethoxysilane. Examples of silane coupling agents having an isocyanurate group include tris-(trimethoxysilylpropyl)isocyanurate. Examples of silane coupling agents having a ureido group include 3-ureidopropyltrialkoxysilane. Examples of silane coupling agents having an acid anhydride group include 3-(trimethoxysilyl)propyl succinic anhydride.

[0141] The silane coupling agent may be a silane coupling agent having an epoxy group, such as 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane, such as 3-glycidoxypropyltriethoxysilane.

[0142] In the photosensitive resin composition of the present invention, the content of the silane coupling agent (F) may be 0.1 to 5 wt %, 0.3 to 3 wt %, or 0.4 to 2 wt % based on the total weight of the composition. The composition contains a solid content and a solvent.

[0143] If the content of the (F) silane coupling agent is within the above range, the composition has excellent crack resistance, high reflectance, excellent adhesive strength, and low tackiness, and is therefore suitable for forming into a film.

[0144] The (F) silane coupling agent may be a commercially available product, and examples thereof 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-9007N, and X-12-967C manufactured by Shin-Etsu Chemical Co., Ltd.

[0145] [(G) Resin having a urethane bond]

[0146] The photosensitive resin composition according to an embodiment of the present invention may further contain (G) a resin having a urethane bond. The (G) resin having a urethane bond may be a resin having excellent flexibility.

[0147] By using the (G) resin having a urethane bond, the photosensitive resin composition does not tear even on flexible substrates or thin plates, enables lamination work of a uniform thickness, and can have excellent crack resistance and tear resistance against external impact and bending.

[0148] The (G) resin having a urethane bond of the present invention may include a modified urethane resin, and the resin having a urethane bond may be an ester type urethane, an ether type urethane, a modified urethane acrylate, a modified urethane epoxy, a silicon-modified urethane, a fluorine-modified urethane, or the like, and may be, for example, a modified urethane epoxy acrylate containing an epoxy group.

[0149] The resin (G) having a urethane bond of the present invention may be a known compound having a urethane bond, such as a reaction product of an isocyanate compound (e.g., monoisocyanate, diisocyanate, polyisocyanate) with a compound having an OH group (e.g., polyhydric alcohol such as monohydric alcohol, polyester polyol, polyether polyol, or epoxy (meth)acrylate), or a modified product thereof.

[0150] In the present invention, the resin (G) having a urethane bond may be one having a carboxyl group or an epoxy group, or one having a (meth)acryloyl group, such as the following carboxyl group-containing resin (1), epoxy group-containing resin (2), or (meth)acryloyl group-containing resin (3), (4), or (5).

[0151] (1) A carboxyl group-containing photosensitive polyurethane resin obtained by the polyaddition reaction of a diisocyanate with a monocarboxylic acid compound having an ethylenically unsaturated double bond, such as a bifunctional epoxy resin (meth)acrylate, such as bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bixylenol epoxy resin, or phenol type epoxy resin, or a partial anhydride or modified product thereof, with a carboxyl group-containing dialcohol compound and a diol compound.

[0152] (2) A urethane-modified epoxy resin having a urethane bond and two or more epoxy groups in the molecule, obtained by reacting a urethane bond-containing compound having an isocyanate group, which is obtained by reacting a polyhydroxy compound with a polyisocyanate compound, with a hydroxy group-containing epoxy compound.

[0153] (3) Urethane resins obtained by the polyaddition reaction of diisocyanates such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates with diol compounds such as polycarbonate-based polyols, polyether-based polyols, polyester-based polyols, polyolefin polyols, acrylic polyols, epoxy resins having hydroxy groups (when these are used, urethane resins having epoxy groups are obtained), bisphenol A-based alkylene oxide adduct diols, and compounds having phenolic hydroxyl groups and alcoholic hydroxyl groups.

[0154] (4) A photosensitive polyurethane resin obtained by replacing part or all of the diisocyanate in (3) above with 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 subjecting such an isocyanate and the diol compound to a polyaddition reaction.

[0155] (5) A (meth)acrylate-terminated photosensitive polyurethane resin obtained by adding a compound having one hydroxyl group and one or more (meth)acryloyl groups in the molecule, such as a hydroxyalkyl (meth)acrylate, during the synthesis of either the resin (3) or (4) above.

[0156] As described above, one resin may have at least two of the carboxyl group, epoxy group, and methacryloyl group.

[0157] The (G) resin having a urethane bond may be (1) a carboxyl group-containing resin, (2) an epoxy group-containing resin, or (5) a (meth)acryloyl group-containing resin.

[0158] 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-tolylene diisocyanate, naphthalene-1,5-diisocyanate-o-xylylene diisocyanate, m-xylylene diisocyanate, and 2,4-tolylene dimer. Examples of aliphatic polyisocyanates include tetramethylene diisocyanate, hexamethylene diisocyanate, methylene diisocyanate, trimethylhexamethylene diisocyanate, 4,4-methylenebis(cyclohexyl isocyanate), and isophorone diisocyanate. Examples of alicyclic polyisocyanates include bicycloheptane triisocyanate. For example, the diisocyanate may be an aliphatic isocyanate.

[0159] When the (G) resin 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 to 200 mg KOH / g, or 45 to 120 mg KOH / g. If the acid value of the carboxyl group-containing resin is in the range of 40 to 200 mg KOH / g, the adhesion of the cured coating is obtained and alkaline development is facilitated, thereby suppressing dissolution of exposed areas in the developer and preventing excessive line narrowing, making it easy to draw a normal resist pattern.

[0160] When the (G) resin having a urethane bond is a carboxyl group-containing resin having a urethane bond, the weight-average molecular weight of the carboxyl group-containing resin varies depending on the resin skeleton, but may be 2,000 to 150,000 g / mol, 5,000 to 50,000 g / mol, or 2,000 to 50,000 g / mol. A weight-average molecular weight within this range provides good tackiness, resulting in good moisture resistance of the cured film and reduced film loss during development. Furthermore, a weight-average molecular weight within this range provides good resolution, developability, and storage stability.

[0161] (G) Examples of commercially available resins having a urethane bond (e.g., a carboxyl group-containing resin having a urethane bond) include UXE-3000 (Nippon Kayaku Co., Ltd.), EPU-7N (urethane-modified epoxy resin; ADEKA Corporation), and Ebecryl 210 (aromatic urethane acrylate; Daicel Allnex Co., Ltd.).

[0162] In the photosensitive resin composition of the present invention, the content of the resin having a urethane bond (G) may be 0.1 to 15 wt %, 5 to 13 wt %, or 8 to 12 wt % of the total composition. The composition contains a solid content and a solvent. When the content of the resin having a urethane bond (G) is within the above range, the composition has excellent flexibility and crack resistance, and can exhibit appropriate tackiness, as well as excellent printability and drying properties.

[0163] In the photosensitive resin composition of the present invention, the weight-average molecular weight of the (G) resin having a urethane bond may be 2,000 to 150,000 g / mol, or 2,000 to 50,000 g / mol. When the weight-average molecular weight of the (G) resin having a urethane bond is within the above range, the composition can have excellent crack resistance and flexibility.

[0164] [Other optional ingredients]

[0165] The photosensitive resin composition of the present invention may contain various additives as optional components, if necessary. Specifically, the composition may contain a thermosetting catalyst, a dispersant, an antioxidant, a colorant, an epoxy resin, an oxetane compound, a (meth)acrylic resin, other additives, or a mixture of two or more of these. The optional components may include one or more of the following materials:

[0166] <Epoxy resin>

[0167] The epoxy resin of the present invention may be a known, commonly used compound having one or more epoxy groups. For example, the epoxy resin may not overlap with the aforementioned components (A) to (G). For example, it may be a compound having two or more epoxy groups. For example, monoepoxy compounds such as butyl glycidyl ether, phenyl glycidyl ether, and glycidyl (meth)acrylate, bisphenol A epoxy resins, bisphenol S epoxy resins, bisphenol F epoxy resins, phenol novolac epoxy resins, cresol novolac epoxy resins, aliphatic ring epoxy resins, 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, triglycidyl tris(2-hydroxyethyl)isocyanurate, and other compounds having two or more epoxy groups per molecule may be used alone or in combination depending on the required properties.

[0168] Examples of compounds having two or more epoxy groups include jER828, jER834, jER1001, and jER1004 from Mitsubishi Chemical Corporation, Epicron 840, Epicron 850, Epicron 1050, and Epicron 2055 from DIC Corporation, Epotohto D-011, YD-013, YD127, and YD-128 from Nippon Steel Chemical & Materials, and DER317 and DER33 from Dow Chemical Japan. 1. Bisphenol A epoxy resins such as DER661, DER664, Sumiepoxy ESA-011, ESA-014, ELA-115, ELA128 from Sumitomo Chemical Co., Ltd., AER330, AER331, AER661, AER664 from Asahi Kasei Materials Corporation (all trade names); jERYL903 from Mitsubishi Chemical Corporation, Epicron 152, Epicron 165 from DIC Corporation, and Nippon Steel Chemical & Materials Co., Ltd. Brominated epoxy resins such as Epotohto YDE-400 and YDE-500 from Aruz Corporation, DER542 from Dow Chemical Japan, Sumiepoxy ESB-400 and ESB-700 from Sumitomo Chemical Co., Ltd., AER711 and AER714 from Asahi Kasei Materials Corporation (all trade names); jER152 and jER154 from Mitsubishi Chemical Corporation, DEN431 and DEN438 from Dow Chemical Japan, and DIC Corporation. Epicron N-730, Epicron N-770, Epicron N-865, Epotohto YDC-701, YDC-704 from Nippon Steel Chemical & Materials Co., Ltd., EPPN-201, EPPN-1025, EPPN-1020, EPPN-104S, RE-306, NC-3000 from Nippon Chemical Co., Ltd., Sumiepoxy ESCN-195X, ESCN-220 from Sumitomo Chemical Co., Ltd., AER from Asahi Kasei Materials Co., Ltd.Novolac epoxy resins such as ECN-235, ECN-299, YDCN-700-2, YDCN-700-3, YDCN-700-5, YDCN-700-7, YDCN-700-10, YDCN-704, YDCN-704A from Nippon Steel Chemical & Materials Co., Ltd., and Epiclon N-680, N-690, and N-695 from DIC Corporation (all trade names); bisphenol F epoxy resins such as Epiclon 830 from DIC Corporation, jER807 from Mitsubishi Chemical Corporation, and Epotohto YDF-175 and YDF-2004 from Nippon Steel Chemical & Materials Co., Ltd. (all trade names); Epoxy resins; hydrogenated bisphenol A type epoxy resins such as Epotohto ST-2004, ST-2007, and ST-3000 (trade names) from Nippon Steel Chemical & Materials Co., Ltd.; glycidyl amine type epoxy resins such as jER604 from Mitsubishi Chemical Corporation and Epotohto YH-434 from Nippon Steel Chemical & Materials Co., Ltd.; Sumiepoxy ELM-120 from Sumitomo Chemical Co., Ltd. (all trade names); hydantoin type epoxy resins; alicyclic epoxy resins such as Celoxide 2021 from Daicel Corporation (all trade names); YL-933 from Mitsubishi Chemical Corporation and TEN from Dow Chemical Japan Co., Ltd.trihydroxyphenylmethane-type epoxy resins such as EPPN-501, EPPN-502 (all trade names); bixylenol-type or biphenol-type epoxy resins or mixtures thereof such as YL-6056, YX-4000, YL-6121 (all trade names) from Mitsubishi Chemical Corporation; bisphenol S-type epoxy resins such as EBPS-200 from Nippon Kayaku Co., Ltd., EPX-30 from ADEKA Corporation, and EXA-1514 (trade name) from DIC Corporation; bisphenol A novolac-type epoxy resins such as jER157S (trade name) from Mitsubishi Chemical Corporation; jER from Mitsubishi Chemical Corporation Tetraphenylolethane type epoxy resins such as YL-931 (all trade names); heterocyclic epoxy resins such as TEPIC (all trade names) from Nissan Chemical Industries, Ltd.; diglycidyl phthalate resins such as Blenmar DGT from NOF Corporation; tetraglycidyl xylenoylethane resins such as ZX-1063 from Nippon Steel Chemical & Materials Co., Ltd.; naphtha resins such as ESN-190, ESN-360 from Nippon Steel Chemical & Materials Co., Ltd., and HP-4032, EXA-4750, and EXA-4700 from DIC Corporation. Examples of suitable epoxy resins include, but are not limited to, ethylene-containing epoxy resins; epoxy resins having a dicyclopentadiene skeleton, such as HP-7200 and HP-7200H manufactured by DIC Corporation; glycidyl methacrylate copolymer epoxy resins, such as CP-50S and CP-50M manufactured by NOF Corporation; cyclohexylmaleimide and glycidyl methacrylate copolymer epoxy resins; and CTBN-modified epoxy resins (e.g., YR-102 and YR-450 manufactured by Nippon Steel Chemical & Materials Co., Ltd.). Among these, bisphenol A-type epoxy resins, heterocyclic epoxy resins, and mixtures thereof are preferred, especially those with excellent discoloration resistance. These epoxy resins may be used singly or in combination of two or more.

[0169] In the photosensitive resin composition of the present invention, the epoxy resin may be a bisphenol-based epoxy resin, for example, a bisphenol-epoxy-based epoxy resin having two or more epoxy groups. The amount of the bisphenol-based epoxy resin having two or more epoxy groups used in the present invention may be 1 to 15 wt %, 1 to 10 wt %, or 3 to 10 wt % of the total composition. The composition contains a solid content and a solvent.

[0170] When the content of the epoxy resin is within the above range, the coating film formed by the composition has excellent adhesion, heat resistance, and pencil hardness, and is well cured, thereby solving problems such as yellowing and difficulty in achieving high reflectance after processing.

[0171] In the photosensitive resin composition of the present invention, the weight average molecular weight of the epoxy resin may be 150 to 100,000 g / mol.

[0172] <Oxetane compounds>

[0173] Next, the oxetane compound will be described.

[0174] [ka]

[0175] (In the formula, R 1represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. Specific examples of oxetane compounds containing an oxetane ring represented by the formula (1) include 3-ethyl-3-hydroxymethyloxetane (Toagosei Co., Ltd., trade name OXT-101), 3-ethyl-3-(phenoxymethyl)oxetane (Toagosei Co., Ltd., trade name OXT-211), 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane (Toagosei Co., Ltd., trade name OXT-212), 1,4-bis{[(3-ethyl-3-oxetanyl)methoxy]methyl}benzene (Toagosei Co., Ltd., trade name OXT-121), and bis(3-ethyl-3-oxetanylmethyl)ether (Toagosei Co., Ltd., trade name OXT-221). Further examples include phenol novolac-type oxetane compounds. Such an oxetane compound may be used in combination with the epoxy compound or may be used alone.

[0176] <(Meth)acrylic resin>

[0177] The (meth)acrylic resin is a photocurable resin. The photocurable resin is not particularly limited as long as it is a resin that is cured by irradiation with active energy rays and exhibits electrical insulation, and may be, for example, a compound having one or more ethylenically unsaturated bonds in the molecule. For example, the (meth)acrylic resin may not overlap with the above-mentioned components (A) to (G).

[0178] The compound having an ethylenically unsaturated bond may be a known or commonly used photopolymerizable oligomer, photopolymerizable monomer, or photopolymerizable vinyl monomer. The photopolymerizable oligomer may be an unsaturated polyester oligomer, a (meth)acrylate oligomer, or the like. The (meth)acrylate oligomer may be an epoxy (meth)acrylate such as phenol novolac epoxy (meth)acrylate, cresol novolac epoxy (meth)acrylate, or bisphenol-type epoxy (meth)acrylate, a urethane (meth)acrylate, an epoxy urethane (meth)acrylate, a polyester (meth)acrylate, a polyether (meth)acrylate, or a polybutadiene-modified (meth)acrylate.

[0179] Examples of the photopolymerizable monomer or photopolymerizable vinyl monomer include known and commonly used ones, for example, 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, vinyl-t-butyl ether, vinyl-n-amyl ether, vinyl isoamyl ether, vinyl-n-octadecyl ether, vinyl cyclohexyl ether, ethylene glycol monobutyl ether, and triethylene glycol monomethyl ether; (meth)acrylamides such as acrylamide, methacrylamide, N-hydroxymethylacrylamide, N-hydroxymethylmethacrylamide, N-methoxymethylacrylamide, N-ethoxymethylacrylamide, and N-butoxymethylacrylamide; aryl compounds such as triallyl isocyanurate, diaryl phthalate, and diaryl isophthalate; 2-ethylhexyl (meth)acrylate, lauric acid, and the like. (Meth)acrylic acid esters such as methyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, isobornyl (meth)acrylate, phenyl (meth)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)acrylates, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate;Examples include 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 hydroxypivalic acid neopentyl glycol ester di(meth)acrylate; and isocyanurate-type poly(meth)acrylates such as tris[(meth)acryloxyethyl]isocyanurate, and these can be used alone or in combination of two or more types.

[0180] In the photosensitive resin composition of the present invention, the (meth)acrylic resin may be an unsaturated polyester oligomer, a (meth)acrylate oligomer, or the like, and may be, for example, a hexafunctional flexible acrylic oligomer. The amount of the (meth)acrylic resin may be 1 to 15 wt %, 1 to 10 wt %, or 5 to 10 wt % of the total composition. The composition contains a solid content and a solvent. When the content of the (meth)acrylic resin is within the above range, the coating film can be cured to an appropriate level with excellent resolution and undercut.

[0181] <Thermosetting catalyst>

[0182] The composition of the present invention may further contain at least one of a curing agent or a curing catalyst as a thermosetting catalyst. For example, the thermosetting catalyst may not overlap with the components (A) to (G) described above.

[0183] The curing agent may be, for example, a polyfunctional phenolic compound, a polycarboxylic acid and its acid anhydride, an aliphatic or aromatic primary or secondary amine, a polyamide resin, an isocyanate compound, a polymercapto compound, or the like. The curing agent may be, for example, a polyfunctional phenolic compound, a polycarboxylic acid and its acid anhydride, and excellent workability and insulating properties can be obtained by using such a curing agent. The polyfunctional phenolic compound is not particularly limited as long as it has two or more phenolic hydroxyl groups per molecule, and may be, for example, a known or commonly used compound. For example, the polyfunctional phenolic compound may be a phenol novolac resin, a cresol novolac resin, bisphenol A, allylated bisphenol A, bisphenol F, a bisphenol A novolac resin, or a vinylphenol copolymer resin. The polyfunctional phenolic compound may be, for example, bisphenol A, which provides high reactivity and improved heat resistance. The polyfunctional phenolic compound can undergo an addition reaction with at least one epoxy compound or oxetane compound in the presence of an appropriate curing catalyst. The polycarboxylic acid and its acid anhydride may be, for example, a compound having two or more carboxyl groups in one molecule and its acid anhydride, such as a copolymer of (meth)acrylic acid, a copolymer of maleic anhydride, a condensate of a dibasic acid, etc. Commercially available products include JONCRYL (product group name) from BASF, SMA Resin (product group name) from Sartomer, and polyazelaic anhydride from New Japan Chemical Co., Ltd.

[0184] The curing catalyst may be a compound that can act as a curing catalyst in the reaction between a thermosetting resin, such as an epoxy compound or an oxetane compound, and a curing agent, or a compound that acts as a polymerization catalyst when a curing agent is not used. Specific examples of the curing catalyst include tertiary amines, tertiary amine salts, quaternary ammonium salts, tertiary phosphines, crown ether compounds, and phosphonium ylides, and these may be used alone or in combination of two or more.

[0185] For example, imidazoles such as 2E4MZ, C11Z, C17Z, and 2PZ (trade names), imidazole AZINE compounds such as 2MZ-A and 2E4MZ-A (trade names), imidazole isocyanurates such as 2MZ-OK and 2PZ-OK (trade names), imidazole hydroxymethyl compounds such as 2PHZ and 2P4MHZ (trade names; Shikoku Chemical Industry Co., Ltd.), dicyandiamide and its derivatives, melamine and its derivatives, diaminomaleonitrile and its derivatives, diethylenetriamine, triethylenetetramine, tetraethylenepentasiloxane ... amines such as methyltriamine, 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., Inc.); or organic phosphine compounds such as triphenylphosphine, tricyclohexylphosphine, tributylphosphine, and methyldiphenylphosphine.

[0186] In the photosensitive resin composition of the present invention, the curing catalyst may be an amine-based, phosphine-based, or imidazole-based curing catalyst, such as a melamine-based amine curing catalyst. The amount of the curing catalyst may be 0.1 to 10 wt %, 0.1 to 5 wt %, or 0.1 to 3 wt % of the total composition.

[0187] When the content of the curing catalyst is within the above range, the coating film is sufficiently cured, and therefore the coating film has excellent adhesion, pencil hardness, and heat resistance, and the curing time can be set appropriately while preventing a decrease in developability.

[0188] <Antioxidants>

[0189] The photosensitive resin composition of the present invention may also contain an antioxidant. The inclusion of an antioxidant can prevent oxidative degradation of curable resins and the like, suppress discoloration, and also improve heat resistance and resolution (line width reproducibility). While some types of white colorants may reflect and absorb light, thereby degrading resolution, the inclusion of an antioxidant can achieve good resolution regardless of the type of white colorant. The antioxidant may be a radical scavenger that neutralizes generated radicals, or a peroxide decomposition inhibitor that decomposes generated peroxides into harmless substances and prevents the generation of new radicals. The antioxidant may be used alone or in combination of two or more.

[0190] Antioxidants that act as radical scavengers include, for example, hydroquinone, 4-t-butylcatechol, 2-t-butylhydroquinone, hydroquinone monomethyl ether, 2,6-di-t-butyl-p-cresol, 2,2-methylene-bis(4-methyl-6-t-butylphenol), 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-trimethyl-2,4,6 ... Examples of suitable compounds include phenolic compounds such as (3,5-di-t-butyl-4-hydroxybenzyl)benzene and 1,3,5-tris(3',5'-di-t-butyl-4-hydroxybenzyl)-S-triazine-2,4,6-(1H,3H,5H)trione, quinone compounds such as menaquinone and benzoquinone, and amine compounds such as bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate and phenothiazine. Commercially available products include, for example, IRGANOX 1010 (all trade names, BASF Japan Ltd.).

[0191] Examples of antioxidants that act as peroxide decomposers include phosphorus compounds such as triphenyl phosphite, and sulfur compounds such as pentaerythritol tetralauryl thiopropionate, dilauryl thiodipropionate, and distearyl-3,3'-thiodipropionate.

[0192] For example, the antioxidant may be a phenolic compound, and when used, it is possible to suppress discoloration, improve heat resistance, and reproduce better resolution.

[0193] Furthermore, antioxidants, such as phenolic antioxidants, can be used in combination with heat stabilizers, and when used in combination, more excellent effects can be achieved.

[0194] The heat stabilizer may be, for example, a phosphorus-based, hydroxylamine-based, or sulfur-based heat stabilizer, etc. The heat stabilizer may be used alone or in combination of two or more.

[0195] For example, the antioxidant may be a hydroxylamine-based antioxidant, a sulfur-based antioxidant, or a phenol-based antioxidant. When a phenol-based antioxidant is used, its amount may be 0.01 to 5 wt % or 0.03 to 3 wt % based on the total composition. By adding the antioxidant in an amount of 0.01 to 1 wt % or more, the effects of adding the antioxidant can be reliably obtained. By adding the antioxidant in an amount of 1 wt % or less, good alkaline development can be achieved without inhibiting the photoreaction, and good tack-dryness and coating film physical properties can be ensured.

[0196] <Organic solvents>

[0197] The photosensitive resin composition of the present invention may contain an organic solvent for the purpose of adjusting the viscosity during production of the composition or during application to a substrate or base material. Examples of the organic solvent that can be used include well-known and commonly used organic solvents, such as esters; aliphatic hydrocarbons such as octane and decane; and petroleum-based solvents such as petroleum ether, petroleum naphtha, and solvent naphtha. These organic solvents can be used alone or in combination of two or more.

[0198] <Other additives>

[0199] The photosensitive resin composition of the present invention may also contain other additives known and commonly used in the field of electronic materials, such as thermal polymerization inhibitors, ultraviolet absorbers, plasticizers, flame retardants, antistatic agents, antiaging agents, antibacterial and antifungal agents, defoaming agents, leveling agents, thickeners, adhesion promoters, thixotropic agents, photoinitiator assistants, viscosity enhancers, curing accelerators, release agents, surface treatment agents, dispersants, dispersion assistants, surface modifiers, and stabilizers.

[0200] The photosensitive resin composition of the present invention may have a phosphorus content of 500 to 5000 ppm.

[0201] By making the phosphorus content of the photosensitive resin composition 500 ppm or more, it is possible to improve the surface hardening and enhance the gold plating resistance and adhesion, and by making the phosphorus content 5000 ppm or less, it is possible to increase the reaction rate of the silicone encapsulant.

[0202] If the phosphorus content is less than 500 ppm, the pencil hardness will be 3H, the adhesion after gold plating will be poor, the gloss will be low, and the solder resist opening (SRO) may not be formed well.On the other hand, if the phosphorus content exceeds 5,000 ppm, the reactivity of the silicone encapsulant will be very low, the developability and reflectivity will be low, and it may be difficult to form the SRO.

[0203] [Dry film and its manufacturing method]

[0204] Another embodiment of the present invention relates to a dry film having a photosensitive resin layer formed by coating a photosensitive resin composition on a first film and drying the coated photosensitive resin composition.

[0205] To form a dry film, the composition of the present invention is first diluted with an organic solvent to adjust the viscosity to an appropriate level, and then coated onto a first film to a uniform thickness, for example, in the range of 40 to 60 μm, using a comma coater, blade coater, lip coater, road coater, squeeze coater, reverse coater, transfer roll coater, gravure coater, microgravure coater, spray coater, etc. The coated composition is then typically dried at a temperature in the range of 40 to 120°C for 1 to 30 minutes to form a photosensitive resin layer, thereby forming a dry film.

[0206] There are no particular limitations on the thickness of the coating film, but in general, the thickness after drying may be 10 to 150 μm, 10 to 80 μm, or 10 to 60 μm.

[0207] The first film may be a plastic film, such as a polyester film such as polyethylene terephthalate (PET), a polyimide film, a polyamideimide film, a polypropylene film, or a polystyrene film, and may be, for example, polyethylene terephthalate. The thickness of the first film is not particularly limited, but may generally be appropriately selected within the range of 10 to 150 μm. The first film may be applied to a metal foil such as copper foil or aluminum foil. The first film may be subjected to a release treatment such as acrylic or silicone.

[0208] Since the dry film of the present invention is white, it may be used to reflect light generated from light-emitting diodes (LEDs) or electroluminescent devices (ELs) used as light sources in lighting systems and backlights for liquid crystal displays in mobile terminals, notebook PCs, tablet PCs, monitors, smartphones, personal computers, televisions, etc. The dry film of the present invention may be applied to LEDs and light-emitting PCBs.

[0209] To produce a cured coating on a printed wiring board using a dry film, the second film, which serves the purpose of protecting the dry film, is peeled off, and the exposed resin layer of the dry film is placed on the circuit-formed substrate and attached using a laminator or the like, forming a resin layer on the circuit-formed substrate. The formed resin layer is then exposed to light, developed, heated, and cured to form a cured coating. The second film can be peeled off either before or after exposure.

[0210] [Cured product and method for producing the same]

[0211] The cured product of the present invention can be obtained by curing the photosensitive resin composition of the present invention or the solder resist layer of the dry film of the present invention.

[0212] The cured product of the present invention can be suitably used in printed wiring boards, electronic components, etc. The cured product of the present invention has excellent crack resistance, high resolution, and dielectric properties including low dielectric constant and low dielectric loss tangent. The cured product of the present invention also has excellent heat resistance and linear expansion coefficient.

[0213] For example, the cured product of the present invention may be a solder resist.

[0214] The solder resist may be prepared by applying the photosensitive resin composition of the present invention to a substrate to form a photosensitive resin layer, selectively exposing the photosensitive resin layer to active energy rays using a photomask having a predetermined pattern formed thereon, and developing the unexposed portions with a dilute alkaline aqueous solution (e.g., a 0.3 to 3 wt % sodium carbonate aqueous solution) to form a pattern. Alternatively, in the case of a dry film, a patterned solder resist can be formed on the substrate by peeling off the first film of the dry film after exposure and then developing the resulting resin layer, provided that the properties are not impaired. Furthermore, the first film can be peeled off from the dry film before exposure, and the exposed resin layer can be exposed and developed.

[0215] [Printed wiring board and its manufacturing method]

[0216] The printed wiring board of the present invention may comprise a cured film obtained by curing the photosensitive resin layer of the dry film of the present invention or the cured product of the photosensitive resin composition of the present invention.

[0217] The printed wiring board of the present invention may include a cured product obtained from the photosensitive resin composition of the present invention or a photosensitive resin layer of a dry film. A method for producing a printed wiring board of the present invention involves, for example, adjusting the viscosity of the photosensitive resin composition of the present invention using the organic solvent to a level suitable for the coating method, applying it to a substrate by a method such as dip coating, flow coating, roll coating, bar coating, screen printing, or curtain coating, and then evaporating and drying (pre-drying) the organic solvent contained in the composition at a temperature of 60 to 100°C to form a tacky-free resin layer. Alternatively, in the case of a dry film, the resin layer can be bonded to a substrate using a laminator or the like so that the resin layer is in contact with the substrate, and then the first film can be peeled off to form the resin layer on the substrate.

[0218] The substrates include printed wiring boards and flexible printed wiring boards with circuits formed from copper or the like, as well as materials such as paper phenol, paper epoxy, glass fiber epoxy, glass polyimide, glass fiber / epoxy, glass fiber / paper epoxy, synthetic fiber epoxy, copper foil laminates for high frequency circuits made from fluororesin, polyethylene, polyphenylene ether, polyphenylene oxide cyanate, etc. Examples of such materials include FR-4 substrates, copper foil laminates of all grades (FR-4, etc.), other metal substrates, polyimide film, polyethylene terephthalate film, polyethylene naphthalate (PEN) film, glass substrates, ceramic substrates, and wafer substrates.

[0219] The dry film can be laminated onto a substrate by applying pressure and heat using a vacuum laminator or the like. By using such a vacuum laminator, even if a circuit board with a pre-formed circuit is used and the surface of the circuit board is uneven, the dry film adheres to the circuit board, preventing the inclusion of air bubbles and improving the smoothing of recesses on the board surface. The pressure may be about 0.1 to 2.0 MPa, and the temperature may be 40 to 120°C.

[0220] Furthermore, the cured product can be finally cured by i) irradiating it with active energy rays and then heat-curing (for example, at 100 to 220°C), or ii) irradiating it with active energy rays after heat-curing, or iii) only irradiating it with active energy rays, or iv) only heat-curing, thereby forming a cured film that is excellent in various properties such as adhesion and hardness.

[0221] The cured product of the present invention can be cured by heating at a temperature of, for example, 100 to 220° C. to form a cured film having excellent overall properties such as high reflectance, excellent yellowing resistance, and excellent crack resistance.

[0222] The exposure device used for the active energy ray irradiation may be a device equipped with a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a mercury short arc lamp, or the like, which irradiates ultraviolet (UV) rays in the range of 350 to 450 nm, or may be a direct imaging device (for example, a laser direct imaging device that directly images CAD data in a computer with a laser). The direct imaging lamp light source or laser light source may have a maximum wavelength in the range of 350 to 450 nm. The exposure for image formation varies depending on the thickness, etc., but is generally 10 to 1000 mJ / cm. 2 or 20 to 800 mJ / cm 2 It may be.

[0223] The developing method may be a dipping method, a shower method, a spray method, a brush method, or the like, and the developing solution may be an aqueous alkaline solution of potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, amines, or the like.

[0224] The printed wiring board of the present invention may include a dry film including one or more layers formed from the photosensitive resin composition.

[0225] When forming a printed wiring board, the dry film can be placed on the test substrate and vacuum laminated to transfer the dry film onto the test substrate.

[0226] The first film is then peeled off, and the substrate with the transferred dry film from which the first film has been peeled off can be exposed to UV light using an exposure device. This exposure can harden the exposed areas (the areas irradiated with light). After exposure, the substrate is cooled at room temperature and then placed in a developing machine, where the unexposed areas are developed using an alkaline aqueous solution, completing the formation of the resist pattern. The substrate with the pattern formed by development is post-cured in an oven at 150°C for 1 hour, completing the substrate fabrication. After the final curing, a reflow process is performed, followed by a chip mounting process. This is followed by an encapsulation process in which a silicone encapsulant is prepared on the cured product of the photosensitive resin layer. The photosensitive resin composition of the present invention can improve the yellowing and uncured problems of the silicone encapsulant formed on the cured product by reducing outgassing of the photopolymerization initiator, thereby improving the reaction rate of the silicone encapsulant.

[0227] In the method for producing a printed wiring board including the cured product of the present invention, for example, after the lamination step, an exposure operation can be performed, and then the first film can be peeled off.

[0228] [Silicone encapsulant layer and its manufacturing method]

[0229] The printed wiring board of the present invention may further include a silicone encapsulant layer disposed on the cured product (obtained by curing the photosensitive resin layer). The silicone encapsulant layer may be formed by coating a composition containing silicone to encapsulate and protect the printed wiring board and the solder resist layer.

[0230] In order to protect the light-emitting chip portion and the photosensitive resin layer (or the cured product obtained by curing this), the above-mentioned silicone sealing material layer can be coated.

[0231] An exemplary method for fabricating the silicon encapsulant layer is described below.

[0232] After final curing or reflow has been completed, a dam measuring 2.0 cm wide, 2.0 cm long, and 250-300 μm thick is created on the printed circuit board, and a 1:1 mixture of silicone encapsulant A and B is then added to coat the silicone encapsulant to a thickness of 250-300 μm. This is then cured in a 100°C oven for two hours to complete the primary cure, and then cured in a 150°C oven for four hours to complete the secondary cure of the silicone encapsulant, creating a silicone encapsulant layer.

[0233] To measure the physical properties of the silicone encapsulant layer, the silicone encapsulant layer is peeled off after curing is complete, and the reaction rate of the silicone encapsulant and the amount of photopolymerization initiator remaining in the silicone encapsulant layer can be analyzed. The degree of cure (reaction rate) of the silicone encapsulant can also be measured to determine how much curing has progressed. The reflectance of the silicone encapsulant layer can also be measured.

[0234] For example, the silicon encapsulant layer may include a lower encapsulant region that is a region closer to the solder resist layer and an upper encapsulant region that is a region farther from the solder resist layer.

[0235] For example, the content of the (E) photopolymerization initiator contained in the upper encapsulant region or the lower encapsulant region may be 1,000 ppm or less relative to the content of the (E) photopolymerization initiator contained in the solder resist layer, for example, 900 ppm or less, 800 ppm or less, 700 ppm or less, 600 ppm or less, or 500 ppm or less.

[0236] The amount of photopolymerization initiator contained in the upper or lower encapsulant region is the amount of the photopolymerization initiator transferred from the solder resist layer. That is, by using a trimethylbenzoylphosphine oxide-based compound containing one or more P-O bonds, which is the photopolymerization initiator (E) of the present invention, the amount of photopolymerization initiator transferred to the nearby upper or lower encapsulant region can be reduced.

[0237] For example, if the photopolymerization initiator is transferred to the silicone encapsulant layer due to outgassing, the phosphorus (P) component of the photopolymerization initiator will react with the catalyst component (e.g., platinum catalyst) of the silicone encapsulant layer to inhibit curing, resulting in a decrease in the reaction rate of the silicone encapsulant. This decrease in reaction rate of the silicone encapsulant may cause problems with long-term reliability.

[0238] [Protection film]

[0239] The laminate of the present invention may include the cured product and a protective film.

[0240] In the present invention, in order to remove the photopolymerization initiator, a protective film can be attached after the photosensitive resin layer is finally cured to form a cured product. When the protective film is attached, the photopolymerization initiator remaining in the solder resist layer can be efficiently removed because the protective film has a high affinity for the photopolymerization initiator. Removing this remaining photopolymerization initiator reduces the amount of photopolymerization initiator remaining after the reflow and baking processes. This reduced photopolymerization initiator content increases the reactivity of the silicone encapsulant when the cured product layer is coated with the silicone encapsulant, and this increased reactivity can significantly improve long-term reliability.

[0241] The protective film may be, for example, a polyethylene film, a polytetrafluoroethylene film, a polypropylene film, surface-treated paper, etc. The thickness of the protective film is not particularly limited, but may be, for example, 10 to 150 μm.

[0242] For example, the content of the (E) photopolymerization initiator contained in the protective film may be 1000 ppm or less relative to the content of the (E) photopolymerization initiator contained in the solder resist layer.

[0243] The content of the photopolymerization initiator contained in the protective film is the photopolymerization initiator contained in the solder resist layer that is transferred. That is, by using the trimethylbenzoylphosphine oxide group-containing compound having one or more P-O bonds, which is the photopolymerization initiator (E) of the present invention, the content of the photopolymerization initiator transferred to the nearby protective film can be reduced.

[0244] <Example>

[0245] The present invention will be described in detail below using examples, but the present invention is not limited to the following examples.

[0246] <Synthesis Example 1 (alkali-soluble resin A, copolymer resin)>

[0247] In a flask equipped with a thermometer, a stirrer, a dropping funnel, and a reflux condenser, 325.0 parts by weight of dipropylene glycol monomethyl ether as a solvent was heated to 110°C, and 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 t-butylperoxy-2-ethylhexanoate (Perbutyl-O, NOF Corporation) as a polymerization catalyst was added dropwise over 3 hours. After stirring for 3 hours at 110°C, the polymerization catalyst was deactivated to obtain a resin solution. After cooling this resin solution, 289.0 parts by weight of Daicel's Cyclomer M100, 3.0 parts by weight of triphenylphosphine, and 1.3 parts by weight of hydroquinone monomethyl ether were added, and the mixture was heated to 100°C and stirred to carry out a ring-opening addition reaction of the epoxy group ring, yielding resin solution A. The solids content of the resulting resin solution A was 54.5% by weight, and the acid value of the solids was 79.8 mg KOH / g.

[0248] <Synthesis example 2, D resin solution>

[0249] 200 parts by weight of deionized water and 0.3 parts by weight of sodium sulfate were poured into a pressure vessel equipped with a thermometer, condenser, and stirrer, and dissolved. Subsequently, 5 parts by weight of BPO (benzoyl peroxide) as a polymerization initiator and 5 parts by weight of MSD (α-methylstyrene dimer) as a chain transfer agent were added to a monomer mixture consisting of 10.4 parts by weight of MMA (methyl methacrylate), 5 parts by weight of n-BA (n-butyl acrylate), 24.6 parts by weight of MAA (methacrylic acid), and 60 parts by weight of Stylene (styrene), and then thoroughly dissolved. A dispersant was then added to a concentration of 300 ppm, thoroughly stirred, and the inside of the vessel was purged with nitrogen. The temperature was then raised to allow suspension polymerization. After polymerization was complete, the resulting suspension was filtered through a 30 μm mesh and dried with hot air at 40°C to obtain a particulate resin. The granular resin (copolymer resin) thus obtained was dissolved sufficiently using the organic solvent DPM (dipropylene glycol methyl ether) to a solid content concentration of 50% by weight, and the resulting solution was designated as resin solution D. The acid value of the solid content was 160 mg KOH / g.

[0250] <Synthesis Example 3, Carboxyl Group-Containing Cresol Novolac Epoxy Acrylate Resin A-2>

[0251] 220 parts by weight of cresol novolac epoxy resin was placed in a four-neck flask equipped with a stirrer and reflux condenser, and 214 parts by weight of carbitol acetate was added and dissolved by heating. Next, 0.1 parts by weight of hydroquinone as a polymerization inhibitor and 2.0 parts by weight of dimethylbenzylamine as a reaction catalyst were added to produce a mixture. This mixture was heated to 95-105°C, and 72 parts by weight of acrylic acid was slowly added dropwise, followed by a 16-hour reaction. The reaction product was cooled to 80-90°C, and 106 parts by weight of tetrahydrophthalic anhydride was added and reacted for 8 hours. After cooling, the mixture was removed.

[0252] The photosensitive resin thus obtained, which had both ethylenically unsaturated bonds and carboxyl groups, had a nonvolatile content of 64%, an acid value of the solid matter of 84.4 mg KOH / g, and a weight-average molecular weight Mw of approximately 7,500. Hereinafter, this resin will be referred to as (A-2). The weight-average molecular weight of the obtained resin was measured by GPC.

[0253] Production of photosensitive resin composition

[0254] [Table 1] JPEG2025531167000008.jpg247170JPEG2025531167000009.jpg143170

[0255] Production of dry films of photosensitive resin compositions

[0256] In a dust-free room, using a comma coater, (1) the compositions of each example and comparative example were coated to a uniform thickness (50 μm) onto a first film (PET film) (Toray XD-500P, film thickness: 25 μm). (2) The coated compositions were dried in four temperature chambers ranging from 40 to 120°C (Chamber 1: 60°C, Chamber 2: 80°C, Chamber 3: 100°C, Chamber 4: 100°C). (3) The moderately dried coating on the first film was laminated to a second film (polypropylene, PP film) to produce a dry film. The dried coating thickness was adjusted to be within the range of 60 μm.

[0257] Evaluation example 1: Outgassing, silicon sealant reaction rate, photopolymerization initiator content measurement

[0258] 1. Outgassing content measurement

[0259] The photosensitive resin compositions according to the Examples and Comparative Examples were laminated onto a PET film using a vacuum laminator (CVP-300, manufactured by Nikko Materials Co., Ltd.) in a first chamber at 60°C under conditions of a vacuum pressure of 3 hPa and a vacuum time of 10 seconds to produce a dry film, and the PET film was then peeled off.

[0260] Using a DI exposure device manufactured by Screen, the integrated light meter measured 300mJ / cm 2 Using a Kodak Step Tablet No. 0.2 (41 steps) as a photomask, the entire surface was exposed to light so that 23 steps were formed. Next, development was performed for 60 seconds using a 1.0% Na2CO3 aqueous solution at 30°C under a spray pressure of 0.2 MPa. After that, the film was cured in an oven at 150°C for 60 minutes to obtain a cured photosensitive resin layer.

[0261] A powder sample was collected from the prepared resist layer and placed in a thermal desorption unit (TDU) manufactured by GURSTEL. Specifically, the powder sample was heated at a rate of 60°C / min from 30°C using helium (50 ml / min) as a purge gas, heated to 150°C for 60 minutes, and then desorbed and collected at -50°C. The collected outgas components were separated and analyzed using an Agilent Technologies gas chromatography mass spectrometer (8890 / 5977B). After being quantified in terms of n-dodecane, the weight percentage was measured based on the weight of the photopolymerization initiator contained in the cured photosensitive resin layer.

[0262] The measurement conditions for gas chromatography were as follows: Column: Agilent Technologies capillary column DB-1MS (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, after sample injection, held at 50°C for 2 minutes, heated to 300°C at 12°C / second, and held for 10 minutes after reaching 300°C.

[0263] Separately, as described below, a silicone sealing material was formed on a substrate (a FR-4 Cu film on which a dry film of a photosensitive resin composition was laminated, and then the PET was peeled off), and then the material was heated at 100°C for 2 hours and then at 150°C for 4 hours to be cured.

[0264] The outgas content, silicon reaction rate, and content of photopolymerization initiator transferred to the silicon sealing material and protective film of each example and comparative example were measured and are shown in the following Table 2. The respective measurement methods are described below.

[0265] [Outgassing content measurement method]

[0266] The photopolymerization initiator peak was confirmed by TD-GCMS analysis. The peak was expressed in μg / g, which means how many μg of gas was generated per 1 g of sample, converted to n-dodecane, and the total outgassing of the photopolymerization initiator peak was measured. The peak area ratio of the photopolymerization initiator to the area of ​​n-dodecane, which is the GC-MS REF, was calculated (using the following formula).

[0267] Calculation formula: Area of ​​the photopolymerization initiator analysis peak / Area of ​​the n-dodecane measurement peak

[0268] 2. Measurement of reaction rate and photopolymerization initiator content of silicone encapsulant

[0269] [Calculation of reaction rate and photopolymerization initiator content of silicone encapsulant]

[0270] (1) A dry film of each photosensitive resin composition (white solder resist composition) was laminated onto an FR-4Cu film using a vacuum laminator (CVP-300: manufactured by Nikko Materials Co., Ltd.) in a first chamber at 60°C under conditions of a vacuum pressure of 3 hPa and a vacuum time of 10 seconds, and the PET film was then peeled off.

[0271] Using a DI exposure device manufactured by Screen, the integrated light meter measured 300mJ / cm 2 The photoresist was exposed to light using a Kodak Step Tablet No. 0.2 (41 steps) as a photomask so that 23 steps were formed, and then developed with a 1.0% Na2CO3 aqueous solution at 30°C at a spray pressure of 0.2 MPa for 60 seconds, followed by curing in an oven at 150°C for 60 minutes to obtain a cured photosensitive resin layer (solder resist layer).

[0272] After creating dams measuring 2.0 cm wide, 2.0 cm long, and 250–300 μm thick, they were attached to both ends of the cured photosensitive resin layer on the FR-4Cu film. A 1:1 mixture of silicone encapsulants A and B was added to the space formed by the dams to form a 250–300 μm thick silicone encapsulant layer. The encapsulant was then cured in an oven at 100°C for two hours to complete the primary cure, and then cured in an oven at 150°C for four hours to complete the secondary cure. After the secondary cure was completed, the interface between the cured photosensitive resin layer and the silicone encapsulant layer was peeled off with a utility knife. FT-IR was used to measure the reaction rate in the upper and lower encapsulant regions of the silicone encapsulant layer on a ZnSe crystal plate, and the degree of cure of the silicone encapsulant in the silicone encapsulant layer was measured.

[0273] [Calculation method for silicon reaction rate]

[0274] 1) Samples (top and bottom) of silicone that had not undergone the above-mentioned first and second curing and silicone that had undergone the second curing were prepared.

[0275] 2) Uncured and cured silicon were placed on a ZnSe crystal plate and FT-IR was measured.

[0276] 3) The uncured silicon is used as the reference, and the Si-H peak of the cured silicon is (2160 cm -1 ) and the reaction rate was calculated (using the following formula).

[0277] Calculation formula: Si-H peak height of cured silicon / Si-H peak height of uncured silicon x 100

[0278] (2) The silicone sealant was peeled off with a cutter knife and the content of photopolymerization initiator was measured using gel permeation chromatography.

[0279] Specifically, 0.05 g of the second, final-cured silicone encapsulant was peeled off with a cutter knife from the silicone encapsulant layer formed on the cured photosensitive resin layer to prepare an analytical sample. 0.05 g of the analytical sample was dissolved in 10.0 g of THF and then poured into a vial. To dissolve any undissolved photosensitive resin composition in the solution, the solution was heated for 5 minutes using an ultrasonic vibrator to prepare the sample. Then, 100 μl of the sample was injected into a gel permeation chromatography (GPC) instrument to complete the analysis.

[0280] [Calculation of the amount of photopolymerization initiator transferred to the protective film]

[0281] A PF protective film was attached to the post-cured silicone encapsulant and then left at 40°C and 90% humidity for 24 hours. The PF protective film was then peeled off, and 0.05 g of the PF protective film was peeled off with a utility knife from the silicone encapsulant layer formed on the cured photosensitive resin layer to prepare an analytical sample. 0.05 g of the analytical sample was dissolved in 5.0 g of tetrahydrofuran (THF) and then filled into a vial. To dissolve any undissolved photosensitive resin composition in the solution, the solution was heated for 5 minutes using an ultrasonic vibrator to prepare the sample. 100 μL of the sample was then injected into a gel permeation chromatography (GPC) instrument to complete the analysis.

[0282] [Method and conditions for gel permeation chromatography (GPC) for photopolymerization initiator content analysis]

[0283] The sample was injected into the GPC system using a gel permeation chromatography system with an E2695 separation module by water, a detector with a 2998PDA / 2414 RI column, a flow rate of 0.5 ml / min, two HSP gel HR MB-L columns, and one HSP gel HR column, a temperature of 4°C, and a mobile phase of THF. The analysis was performed by quantifying the peak at 382 nm, the absorption wavelength of the photoinitiator TPO. The same calibration curve was performed on the sample and the reference photoinitiator sample containing 1, 10, and 100 ppm TPO. The calibration curve results for each concentration were used to quantify the photoinitiator contained in the sample.

[0284] (Outgassing content evaluation)

[0285] ◎: Outgas content <500 ppm ○: 500 ppm or less outgassing content < 1,000 ppm △: 1,000 ppm or less outgassing content < 2,000 ppm ×: 2,000 ppm or less outgassing content

[0286] (Silicon upper encapsulation reaction rate evaluation) ◎: 70% or less silicon upper encapsulant reaction rate ○: 55%≦Si upper encapsulant reaction rate<70% △: 40%≦Si upper encapsulant reaction rate<55% ×: Silicon upper encapsulant reaction rate <40%

[0287] (Silicon bottom encapsulant reaction rate evaluation)

[0288] ◎: 50% or less silicon upper encapsulant reaction rate ○: 40%≦Si lower encapsulant reaction rate<50% △: 30%≦Si upper encapsulant reaction rate<40% ×: Silicon upper encapsulant reaction rate <30%

[0289] (Photopolymerization initiator content transferred to the encapsulant)

[0290] ◎: Photopolymerization initiator content <300 ppm ○: 300 ppm≦Photopolymerization initiator content<500 ppm △: 500 ppm≦Photopolymerization initiator content<700 ppm ×: 700 ppm or less photopolymerization initiator content

[0291] [Table 2]

[0292] Referring to Table 2, it can be seen that the outgassing contents of Examples 1 to 10, which contain Photopolymerization Initiator 1 or 2, are significantly lower than those of Comparative Examples 1 to 4, 6, and 7. This significantly reduced outgassing of the photopolymerization initiator improves the yellowing of the silicone encapsulant, thereby significantly increasing the reaction rate of the silicone encapsulant, and the reduced content of photopolymerization initiator transferred to the silicone encapsulant improves the long-term reliability and stability of the product.

[0293] When TPO was used as the photopolymerization initiator as in Comparative Examples 1 to 4, 6, and 7, it was confirmed that the photopolymerization initiator TPO was transferred to and remained in the silicone encapsulant at a content of 700 ppm or more. This, as described herein, reduces the reflectance and reactivity of the silicone encapsulant, which may impair the long-term reliability of the product.

[0294] On the other hand, when only Omnipol TP was used as the photoinitiator as in Examples 1 and 2, the amount of outgassing of the photoinitiator and the amount of photoinitiator transferred to the silicone encapsulant were significantly reduced, thereby maintaining high reflectivity, increasing the reaction rate of the encapsulant region, and improving the long-term reliability and stability of the product.

[0295] Furthermore, when Omnirad TPO L was used as the photoinitiator as in Examples 3 to 10, the amount of outgassing and the amount of photoinitiator transferred to the silicone encapsulant were significantly reduced, which resulted in maintaining high reflectivity, increasing the reaction rate in the encapsulant region, and improving the long-term reliability and stability of the product.

[0296] Next, a protective film (PF) was formed on the silicone encapsulant and kept at 40°C / 90% humidity for 24 hours. After that, the protective film was peeled off and the content of the photopolymerization initiator transferred to the protective film was measured using gel permeation chromatography. The results are shown in Table 3 below.

[0297] (Photopolymerization initiator content evaluation)

[0298] ◎: Photopolymerization initiator content <500 ppm ○: 500 ppm or less photopolymerization initiator content < 2,000 ppm △: 2,000 ppm≦Photopolymerization initiator content<4,000 ppm ×: 4,000 ppm or less photopolymerization initiator content

[0299] [Table 3]

[0300] Referring to Table 3 together with Table 2, it can be seen that the outgassing content of Examples 1 to 10, which contain Photopolymerization Initiator 1 or 2, is significantly lower than that of Comparative Examples 1 to 4, 6, and 7, which contain other photopolymerization initiators. This indicates that the amount of photopolymerization initiator transferred to the protective film, as well as the silicone encapsulant, is also significantly reduced. Specifically, compared to Comparative Examples 1 to 4, 6, and 7, Examples 1 to 10 show significantly less photopolymerization initiator transferred to the protective film (PF). This is because the use of photopolymerization initiators represented by Chemical Formulas 1 and 2 reduces outgassing, preventing the photopolymerization initiator from being transferred to the silicone encapsulant and protective film. As a result, the use of the photopolymerization initiator defined in the present invention increases reflectivity, improves the reaction rate and cure degree of the silicone encapsulant, and improves long-term reliability.

[0301] Evaluation example 2: BHAST test

[0302] The dry films prepared in Examples 3 and 4 and Comparative Examples 1 to 4 were laminated onto a substrate with interdigital electrodes (line / space = 50 μm / 50 μm) using a vacuum laminator (CVP-300, manufactured by Nikko Materials Co., Ltd.) in a first chamber at 60 °C under conditions of 3 hPa vacuum pressure and 10 seconds of vacuum time, followed by pressing under conditions of 0.2 MPa pressure and 10 seconds of pressing to obtain evaluation substrates. After peeling off the PET film, the substrates were exposed using a DI exposure machine (Screen Inc.) at an exposure dose sufficient to obtain 23 steps on a step tablet (41 steps), followed by development (1 wt% Na2CO3, 30 °C, 0.2 MPa) for 60 seconds to complete the substrate preparation. After the substrate preparation was completed, BHAST was performed at 20 V for 250 hours in a chamber at 110 °C and 85% humidity, and the insulation reliability, BHAST resistance, reflectance, etc. were evaluated.

[0303] The results of the BHAST test are shown in Figures 1A and 1B.

[0304] Next, the reflectance was measured after the BHAST test, and the results are shown in Table 4 below. The reflectance was measured at a wavelength of 450 nm using a spectrophotometer (CM-2600d, Konica Minolta Sensing Inc.).

[0305] ◎:90%≦Reflectance ○:87%≦Reflectance<90% △:84%≦Reflectance<87% ×: Reflectance <84%

[0306] In addition, a HAST resistance test was conducted and the results are shown in Table 4 below.

[0307] The dry films produced in each example and comparative example were laminated onto a substrate having interdigital electrodes (line / space = 50 μm / 50 μm) formed thereon using a vacuum laminator (CVP-300: manufactured by Nikko Materials Co., Ltd.) in a first chamber at 60°C under conditions of a vacuum pressure of 3 hPa and a vacuum time of 10 seconds, and then pressed under conditions of a press pressure of 0.2 MPa and a press time of 10 seconds to obtain an evaluation substrate.

[0308] After peeling off the PET film, the integrating light meter measured 300mJ / cm 2 The substrate was exposed to light so that the cured dry film was visible, and then developed for 60 seconds using a 1% Na2CO3 aqueous solution at 30°C under a spray pressure of 0.2 MPa. The substrate was then cured in a 150°C oven for 60 minutes to form a dry film cured coating, producing a HAST evaluation substrate. This evaluation substrate was placed in a high-temperature, high-humidity chamber at 110°C and 85% humidity, charged with 20V, and subjected to an in-chamber HAST (Highly Accelerated Stress Test) test for 250 hours. After 250 hours, the discoloration and elution of the cured dry film coating were evaluated according to the following criteria (equipment manufacturer: Espec Corporation, Ion Migration System, equipment name: NY IM1064).

[0309] ○: No peeling, discoloration, or elution ×: Peeling, discoloration, or elution is observed with the naked eye

[0310] [Table 4]

[0311] Referring to Table 4, it can be seen that Examples 3 and 4 have higher reflectance after the HAST test than Comparative Examples 1 to 4. In addition, it can be seen that Examples 3 and 4 have higher reflectance after the HAST test than Comparative Examples 1 to 4, and that the degree of copper oxidation and corrosion is very small, and there is no peeling, discoloration, or leaching.

[0312] Evaluation example 3: Reflectance test (after reflow and UV treatment)

[0313] The dry films prepared in Examples 1 to 4 and Comparative Examples 1 to 7 were laminated onto copper substrates using a vacuum laminator (CVP-300: manufactured by Nikko Materials Co., Ltd.) in a first chamber at 60°C under conditions of a vacuum pressure of 3 hPa and a vacuum time of 10 seconds, and then pressed under conditions of a press pressure of 0.2 MPa and a press time of 10 seconds.

[0314] After peeling off the PET film, the exposure was measured using a DI exposure device manufactured by Screen, with an integrated light meter measuring 300 mJ / cm 2 The coating was exposed to light using a Kodak Step Tablet No. 0.2 (41 steps) as a photomask to form 23 steps, then developed with a 1% Na2CO3 aqueous solution at 30°C for 60 seconds at a spray pressure of 0.2 MPa, and cured in a 150°C oven for 60 minutes to obtain a substrate. The reflectance of the coating surface on the obtained substrate at a wavelength of 450 nm was measured using a spectrophotometer (CM-2600d, Konica Minolta Sensing, Inc.). Reflow was performed once to three times at 260°C for 10 seconds, and the reflectance was measured. The results are shown in Table 5. After final curing, UV was irradiated at 500 mJ / cm2 using an integrated actinometer. 2 The conditions were passed three times, and the reflectance was measured for each pass. The results are shown in Table 6.

[0315] ◎:90%≦Reflectance ○:87%≦Reflectance<90% △:84%≦Reflectance<87% ×:Reflectance<84%

[0316] [Table 5]

[0317] In Examples 1 to 4, not only the initial reflectance when no reflow was performed, but also the reflectance at 450 nm after one, two, and three reflows, and after one reflow followed by firing, was higher than that of Comparative Examples 1 to 7, and it was confirmed that there was little decrease in reflectance after reflow or firing.

[0318] In particular, in Examples 1 to 4, by using Omnipol TP or Omnirad TPO-L as the photopolymerization initiator, the amount of outgassing is small, which has little effect on the silicon encapsulant, and therefore the baking step can be omitted, allowing high reflectance to be maintained even after reflow.

[0319] However, in Comparative Examples 1 to 7, in order to apply them to backlight unit products, a baking process must be performed after the reflow process to remove the TPO because the TPO photopolymerization initiator affects the curing property with the silicone encapsulant. Furthermore, it was confirmed that the reflectance significantly decreased when the baking process was performed.

[0320] In summary, compared to Comparative Examples 1 to 7, Examples 1 to 4 have reflectances equivalent to or higher than those applicable to actual products, and as explained in Table 2 above, have excellent reactivity and hardening degree of the silicone encapsulant, which can improve the long-term reliability and stability of the product.

[0321] [Table 6] JPEG2025531167000015.jpg51170

[0322] The reflectance at 450 nm of Examples 1 to 4 showed higher initial reflectance than Comparative Examples 1 to 6, and showed a similar trend after three treatments with 500 mJ of UV. After three UV treatments, the reflectance of Examples 1 to 4 was 90.2 to 90.6, but Comparative Examples 1 to 4 showed a reflectance of 73 to 89.7 after three UV treatments, which is likely due to severe yellowing.

[0323] Evaluation example 4: Tested in a chamber at 85°C and 85% humidity, reflectance test in HS chamber

[0324] The dry films prepared in Examples 2 to 4 and Comparative Example 1 were laminated in a first chamber at 60°C using a vacuum laminator (CVP-300: manufactured by Nikko Materials Co., Ltd.) under conditions of 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 to obtain evaluation substrates.

[0325] After peeling off the PET film, the integrating light meter measured 300mJ / cm 2 The substrate was exposed to light so that the reflection intensity was 100%. The film was then developed with a 1% Na2CO3 aqueous solution at 30°C for 60 seconds at a spray pressure of 0.2 MPa, and cured in a 150°C oven for 60 minutes to obtain a substrate. The resulting substrate was placed in a chamber (ETAC's HIFLEX, Temperature and Humidity Chamber) at a temperature of 85°C and humidity of 85% and left for 1000 hours. The reflectance of the substrate at a wavelength of 450 nm after leaving the chamber for 1000 hours was measured using a spectrophotometer (CM-2600d, Konica Minolta Sensing, Inc.). The results are shown in Table 7.

[0326] ◎:90%≦Reflectance ○:87%≦Reflectance<90% △:84%≦Reflectance<87% ×:Reflectance<84%

[0327] [Table 7]

[0328] It was confirmed that in Examples 2 to 4, even when evaluated for a long period of time under high temperature and humidity conditions, the reflectance at 450 nm decreased only slightly even under high temperature and humidity conditions.

[0329] On the other hand, in Examples 2 to 4, the b value after evaluation under high temperature and humidity conditions was smaller than that of Comparative Example 1. This indicates that less yellowing occurred under high temperature and humidity conditions in Examples 2 to 4 than in Comparative Example 1. Since less yellowing occurred in Examples 2 to 4 even under harsh conditions of high temperature and humidity than in Comparative Example 1, Examples 2 to 4 can be more effectively used as materials for backlight units.

[0330] Evaluation example 5: General physical property evaluation

[0331] <Creating an evaluation board>

[0332] The photosensitive resin compositions prepared in each example and comparative example were laminated onto a PET film substrate using a vacuum laminator (CVP-300: manufactured by Nikko Materials Co., Ltd.) in a first chamber at 60°C under conditions of 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 press time of 10 seconds to obtain evaluation substrates. After peeling off the PET film, the substrates were exposed to 300 mJ / cm on an integrating actinometer using a DI exposure device manufactured by Screen Co., Ltd. 2 The film was exposed to light using a Kodak Step Tablet No. 0.2 (41 steps) as a photomask to create 23 steps, and then developed with a 1% Na2CO3 aqueous solution at 30°C at a spray pressure of 0.2 MPa for 60 seconds, followed by final curing in an oven at 150°C to produce the substrate.

[0333] <Pencil hardness>

[0334] Using the substrate, pencils ranging from B to 9H, each having a flattened tip, were pressed at an angle of approximately 45°, and the hardness of the pencil at which the coating did not peel off was recorded.

[0335] <Adhesion>

[0336] A 1 mm grid (10 × 10) was created on the substrate, and transparent adhesive tape was completely attached to the grid. Immediately, one end of the tape was held perpendicular to the substrate and instantly peeled off, and the number of grid squares that were not completely peeled off was counted. The results were reported using the number of remaining grid squares as the numerator and the total number of grid squares (100) as the denominator.

[0337] PASS: 95% or more of the grid remains. NG: Less than 95% of the grid holes remain.

[0338] <Gloss evaluation>

[0339] The gloss of the coating surface of the substrate was measured at an angle of 60° using a gloss colorimeter (BYK E-4430).

[0340] <Solder heat resistance>

[0341] The board was immersed in a solder bath at 288°C for 10 seconds, and then a 1mm grid (10x10) was created on the board. Transparent adhesive tape was completely attached to the grid. Immediately, one end of the tape was held perpendicular to the board and instantly peeled off. The number of grid cells that remained unpeeled was counted. The results were reported using the number of remaining grid cells as the numerator and the total number of grid cells (100) as the denominator.

[0342] PASS: 95% or more of the grid remains. NG: Less than 95% of the grid holes remain.

[0343] [Table 8]

[0344] However, in Comparative Example 5, the photopolymerization initiator content was low, which resulted in insufficient surface curing. As a result, the pencil hardness was low at 3H, the gloss was significantly reduced to 72, the adhesion and solder heat resistance were unsatisfactory, and the developability was also poor. In Comparative Example 6, the photopolymerization initiator content was too high, which resulted in good surface curing. As a result, the adhesion and solder heat resistance were excellent, but the increased curing rate resulted in decreased developability, making it unsuitable for forming an SRO. In Example 7, the pencil hardness was improved to 6H, and the adhesion and solder heat resistance were greatly improved. In Example 8, the pencil hardness was also improved to 6H, and the adhesion and solder heat resistance were also greatly improved.

[0345] Evaluation Example 6: Phosphorus Content Analysis of Photosensitive Resin Composition

[0346] 1) 0.1 g of the photosensitive resin composition of Examples 1 to 8 and Comparative Examples 1 to 6 was accurately weighed and placed in a beaker, and 2 mL of nitric acid was added. The mixture was then heated on a hot plate to react. 2) The sample was temporarily removed from the hot plate and allowed to cool to room temperature. 0.03 mL of hydrochloric acid was added in hot increments to react. 3) After that, a small amount of the nitric acid solution of the sample was left unevaporated, and cooled to room temperature. 1 mL of concentrated nitric acid was then added to completely dissolve the sample. After the sample was completely dissolved, it was diluted with ultrapure water. 4) The phosphorus (P) concentration of the examples and comparative examples was analyzed using an ICP-OES analyzer (Optima series, Perkin Elmer) at wavelengths of 213.617 nm and 214.914 nm.

[0347] [Table 9]

[0348] The phosphorus content was detected to be about 3,000 ppm in the compositions of Examples 1 to 8 and Comparative Examples 1 to 4. In Comparative Example 5, a phosphorus content of about 430 ppm was detected because a phosphorus-containing photopolymerization initiator was not used. In Comparative Example 6, the phosphorus content in the composition was detected to be 5,500 ppm.

Claims

1. (A) a carboxyl group-containing resin that does not contain an aromatic ring; (B) an inorganic filler, and (E) A photopolymerization initiator that is a trimethylbenzoylphosphine oxide group-containing compound containing one or more P—O bonds. A photosensitive resin composition comprising:

2. The photopolymerization initiator (E) which is a trimethylbenzoylphosphine oxide group-containing compound having one or more P—O bonds is *—C(═O)—P(═O)R １ -O-*'moiety (where R １ 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.

3. 2. The photosensitive resin composition according to claim 1, wherein the (E) photopolymerization initiator which is a trimethylbenzoylphosphine oxide group-containing compound having one or more P—O bonds is a trimethylbenzoylphosphine oxide group-containing polymer.

4. The trimethylbenzoylphosphine oxide group-containing polymer has a weight average molecular weight (M ｎ 4. The photosensitive resin composition according to claim 3, wherein the molecular weight of the polymer is 900 g / mol or more.

5. The photosensitive resin composition according to claim 3 , wherein the trimethylbenzoylphosphine oxide group-containing polymer is represented by the following Chemical Formula 1: 【Chemical 1】 a=0-100, b=0-100, c=0-100

6. 2. The photosensitive resin composition according to claim 1, wherein the (E) photopolymerization initiator, which is a trimethylbenzoylphosphine oxide group-containing compound having one or more P—O bonds, contains an alkoxy group.

7. 2. The photosensitive resin composition according to claim 1, wherein the (E) photopolymerization initiator, which is a trimethylbenzoylphosphine oxide group-containing compound having one or more P—O bonds, contains an ethoxy group.

8. 2. The photosensitive resin composition according to claim 1, wherein the photopolymerization initiator (E) is a trimethylbenzoylphosphine oxide group-containing compound having one or more P—O bonds, and is represented by the following Chemical Formula 2: 【Chemistry 2】

9. 2. The photosensitive resin composition according to claim 1, wherein the content of the photopolymerization initiator (E), which is a trimethylbenzoylphosphine oxide group-containing compound having one or more P—O bonds, is 0.01 to 10 wt % based on the total weight of the composition.

10. The photosensitive resin composition according to claim 1 , wherein the (A) carboxyl group-containing resin not containing an aromatic ring contains an unsaturated double bond.

11. The photosensitive resin composition according to claim 1 , further comprising (D) a resin containing an aromatic ring.

12. The photosensitive resin composition according to claim 11, wherein the (D) resin containing an aromatic ring is a melamine resin, a silicone resin, or a resin having a styrene skeleton.

13. The photosensitive resin composition according to claim 1 , further comprising (C) a mercapto-modified (meth)acrylate.

14. The photosensitive resin composition according to claim 1 , further comprising (F) a silane coupling agent.

15. The photosensitive resin composition according to claim 1 , further comprising (G) a resin having a urethane bond.

16. 2. The photosensitive resin composition according to claim 1, wherein the outgassing content of the photosensitive resin composition measured by thermal desorption spectroscopy (TDS) and gas chromatography-mass spectrometry (GC-MS) is 1,000 ppm or less relative to the content of (E) the photopolymerization initiator which is a trimethylbenzoylphosphine oxide group-containing compound having one or more P—O bonds.

17. 2. The photosensitive resin composition according to claim 1, wherein the phosphorus content is 500 to 5,000 ppm.

18. (A) a carboxyl group-containing resin that does not contain an aromatic ring; (C) a mercapto-modified (meth)acrylate, and (E) A photopolymerization initiator that is a trimethylbenzoylphosphine oxide group-containing compound containing one or more P—O bonds. A photosensitive resin composition comprising:

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

20. The photosensitive resin composition according to claim 18, further comprising (F) a silane coupling agent.

21. The photosensitive resin composition according to claim 18, further comprising (G) a resin having a urethane bond.

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

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

24. A printed wiring board comprising the cured product according to claim 23 as a solder resist.

25. 25. The printed wiring board of claim 24, further comprising a silicone encapsulant layer disposed on the solder resist.

26. the silicone encapsulant layer includes an upper encapsulant region and a lower encapsulant region; 26. The printed wiring board according to claim 25, wherein the content of (E) the photopolymerization initiator which is a trimethylbenzoylphosphine oxide group-containing compound having one or more P—O bonds contained in at least one of the upper encapsulant region and the lower encapsulant region is 1,000 ppm or less relative to the content of (E) the photopolymerization initiator which is a trimethylbenzoylphosphine oxide group-containing compound having one or more P—O bonds contained in the solder resist.

27. The cured product according to claim 23, and A laminate comprising a protective film.

28. 28. The laminate according to claim 27, wherein the content of (E) the photopolymerization initiator which is a trimethylbenzoylphosphine oxide group-containing compound having one or more P—O bonds contained in the protective film is 1,000 ppm or less relative to the content of (E) the photopolymerization initiator which is a trimethylbenzoylphosphine oxide group-containing compound having one or more P—O bonds contained in the solder resist.

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