JP2010175609A - Photosensitive composition and solder resist composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive composition for forming a resist film less liable to cause discoloration, such as, yellowing and having superior adhesion with respect to a substrate, or the like, even if it is exposed to high temperature. <P>SOLUTION: The photosensitive composition contains: (A) a polymerizable hydrocarbon compound which is at least one of a polymerizable hydrocarbon monomer and a polymerizable hydrocarbon polymer within a molecule, having at least one carboxyl group per molecule; (B) a compound having at least two cyclic ether groups per molecule; (C) a photopolymerization initiator; and (D) a specific amine compound or a specified phosphine compound. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a photosensitive composition and a solder resist suitably used for forming a solder resist film on a substrate or forming a resist film that reflects light on a substrate on which a light emitting diode chip is mounted. Relates to the composition.

  A solder resist film is widely used as a protective film for protecting a printed wiring board from high-temperature solder.

  The following Patent Document 1 discloses a material for forming the solder resist film. More specifically, Patent Document 1 discloses a solder resist material containing an acrylate prepolymer resin.

  Conventionally, in various electronic device applications, a light emitting diode (hereinafter abbreviated as LED) chip is mounted on the upper surface of a printed wiring board. Of the light generated from the LED, the light reaching the upper surface side of the printed wiring board is also used, so that the light reaching the upper surface of the printed wiring board is reflected with high reflectance. In some cases, a white solder resist film is formed. Not only light directly irradiated from the surface of the LED chip to the side opposite to the printed wiring board but also reflected light that reaches the upper surface side of the printed wiring board and is reflected by the white solder resist film is used. Therefore, the utilization efficiency of the light generated from the LED can be increased.

  The following Patent Document 2 discloses an example of a material for forming a white solder resist film. Specifically, Patent Document 2 discloses a solder resist material containing a silane-modified epoxy resin having a hydrolyzable alkoxy group and an epoxy resin.

  On the other hand, the following Patent Document 3 discloses a white solder resist material containing an acrylate resin and an epoxy resin.

JP 58-25374 A JP 2007-249148 A JP 2007-322546 A

  However, when the resist film made of each material disclosed in Patent Documents 1 to 3 is exposed to a high temperature environment near 200 ° C. such as the temperature at the time of solder reflow, the resist film turns yellow or prints. In some cases, adhesion to a substrate such as a wiring substrate may be reduced.

  An object of the present invention is to provide a photosensitive composition that can form a resist film that hardly undergoes discoloration such as yellowing even when exposed to a high temperature and has excellent adhesion to a substrate, and the photosensitive composition. It is providing the soldering resist composition which consists of an adhesive composition.

  According to a wide aspect of the present invention, (A) at least one polymerizable hydrocarbon compound of a polymerizable hydrocarbon monomer and a polymerizable hydrocarbon polymer having at least one carboxyl group in one molecule, and (B) A compound having at least two cyclic ether groups in one molecule, (C) a photopolymerization initiator, (D) an amine compound (D1) represented by the following formula (1) or represented by the following formula (2): And a phosphine compound (D2).

In Formula (1) or Formula (2), R _{1 to} R ₆ are _one selected from the group consisting of a hydrogen atom, a hydrocarbon group, and an organic group containing an oxygen atom, and R _{1 to} R ₆ are the same. May be different.

In a specific aspect of the present invention, R _{1 to} R ₆ are a chain hydrocarbon group having 2 to 20 carbon atoms or an alicyclic hydrocarbon group having 3 to 12 carbon atoms. In this case, the hydroxyl group generated by the reaction between the compound (D) and the compound (B) can enhance the adhesion to the substrate, and the adhesion when exposed to a high temperature is further unlikely to decrease. .

Preferably, R _{1 to} R ₆ are one hydrocarbon group selected from the group consisting of an ethyl group, an n-propyl group, an n-butyl group, and a cyclohexyl group, whereby the compound (D) and The compound (B) having at least two cyclic ether groups in one molecule reacts appropriately, and the developability of the resist film made of the photosensitive composition can be enhanced.

  In still another specific aspect of the present invention, an inorganic filler having a pH of 6.8 or more and 11 or less is contained, thereby further effectively suppressing discoloration of the resist film when the resist film is formed. can do.

In another specific aspect of the photosensitive composition according to the present invention, the compound (D) is 0.01 to 5 parts by weight with respect to a total of 100 parts by weight of the compound (A) and the compound (B). Contained. In this case, it is possible to more effectively suppress discoloration of the resist film when the resist film is formed, and to effectively improve the adhesion of the resist film to the substrate or the like at a high temperature. The composition is composed of the photosensitive composition of the present invention. Therefore, when a solder resist film is formed, even when exposed to a high temperature, discoloration hardly occurs and adhesion to the substrate does not easily decrease.

  The photosensitive composition according to the present invention comprises at least one polymerizable hydrocarbon compound (A) of the specific polymerizable hydrocarbon monomer and polymerizable hydrocarbon polymer, a compound having at least two cyclic ether groups (B ), A photopolymerization initiator (C) and the specific compound (D), a resist film can be obtained by exposing and developing the photosensitive composition, and the resist film is exposed to a high temperature. Even if it is done, discoloration such as yellowing is difficult to occur, and adhesion to the substrate is difficult to decrease.

It is a partial notch front sectional drawing which shows an example of the LED device which has a soldering resist film | membrane of this invention.

  Hereinafter, the present invention will be clarified by describing specific embodiments and examples of the present invention with reference to the drawings.

[At least one polymerizable hydrocarbon compound (A) of polymerizable hydrocarbon monomer and polymerizable hydrocarbon polymer having at least one carboxy group in one molecule]
The photosensitive composition according to the present invention contains at least one of the specific polymerizable hydrocarbon monomer and the polymerizable hydrocarbon polymer. That is, the photosensitive composition according to the present invention may contain only a polymerizable hydrocarbon monomer as the compound (A), or may contain only a polymerizable hydrocarbon polymer. And a polymerizable hydrocarbon polymer. Further, as the polymerizable hydrocarbon monomer, only one type of polymerizable hydrocarbon monomer may be used, or two or more types of polymerizable hydrocarbon monomers may be used. Similarly, as the polymerizable hydrocarbon polymer, one type of polymerizable hydrocarbon polymer or the like may be used, or two or more types of polymerizable hydrocarbon polymers may be used.

  Examples of the polymerizable hydrocarbon monomer include a monomer having a polymerizable unsaturated group or a monomer having a polymerizable cyclic ether group. Examples of the polymerizable hydrocarbon polymer include acrylic resin, epoxy resin, and olefin resin. In addition, the term “resin” in the present specification includes not only solid resins but also liquid resins and oligomers.

  The monomer having a polymerizable unsaturated group is preferably a compound having a (meth) acryl group. Examples of the compound having a (meth) acryl group include di (meth) acrylates of glycols such as ethylene glycol, methoxytetraethylene glycol, polyethylene glycol or propylene glycol, polyhydric alcohols, ethylene oxide adducts of polyhydric alcohols or polyhydric alcohols. Polyhydric (meth) acrylate of propylene oxide adduct of alcohol, phenol, ethylene oxide adduct of phenol or (meth) acrylate of propylene oxide adduct of phenol, glycerin diglycidyl ether or trimethylolpropane triglycidyl ether, etc. (Meth) acrylate of glycidyl ether and melamine (meth) acrylate.

  Examples of the polyhydric alcohol include hexanediol, trimethylolpropane, pentaerythritol, dipentaerythritol, or tris-hydroxyethyl isocyanurate. Examples of the (meth) acrylate of phenol include phenoxy (meth) acrylate and di (meth) acrylate of bisphenol A.

  In the present specification, “(meth) acryl” means acryl or methacryl, and “(meth) acrylate” means acrylate or methacrylate.

  The monomer having a polymerizable unsaturated group preferably includes an acrylic monomer having at least two unsaturated double bond groups, and more preferably, the monomer having a polymerizable unsaturated group has at least two unsaturated groups. An acrylic monomer having a saturated double bond group. When the monomer having a polymerizable unsaturated group includes an acrylic monomer having two or more unsaturated double bond groups, it is possible to increase the crosslink density of the finally obtained resist film. The resist film is difficult to discolor even when exposed to.

  The polymerizable hydrocarbon polymer is preferably a resin having a carboxyl group mentioned in the following (i) to (iv).

(I) a resin obtained by copolymerizing a compound having an unsaturated carboxylic acid and an unsaturated double bond (ii) a (meth) acrylic copolymer resin (b1) having a carboxyl group and an oxirane ring and ethylene in one molecule A resin obtained by reacting a compound (b2) having a polymerizable unsaturated group (iii) a compound having one epoxy group and an unsaturated double bond in one molecule and a compound having an unsaturated double bond Resin in which unsaturated monocarboxylic acid is reacted with polymer and then secondary hydroxyl group produced by reaction is reacted with saturated or unsaturated polybasic acid anhydride (iv) Polymer having hydroxyl group is saturated or After reacting an unsaturated polybasic acid anhydride, the carboxylic acid group produced by the reaction is reacted with a compound having one epoxy group and an unsaturated double bond in one molecule. Having a group resin

  In addition, since the yellowing at a high temperature of the resist film can be further enhanced, the polymerizable hydrocarbon polymer is preferably (ii) the carboxyl group-containing resin.

  The (meth) acrylic copolymer resin (b1) having a carboxyl group includes, for example, a (meth) acrylic acid ester (b11), a compound having one unsaturated group and at least one carboxyl group in one molecule ( and b12) are copolymerized.

  Examples of the (meth) acrylic acid ester (b11) include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, and hexyl (meth) acrylate. It is done. Furthermore, examples of the (meth) acrylic acid ester (b11) include a hydroxyl group-containing (meth) acrylic acid ester and glycol-modified (meth) acrylate. One type of (meth) acrylic acid ester (b11) may be used, or two or more types of (meth) acrylic acid ester (b11) may be used in combination.

  Examples of the hydroxyl group-containing (meth) acrylic acid ester include 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, or caprolactone-modified 2-hydroxyethyl (meth) acrylate. As glycol-modified (meth) acrylate, methoxydiethylene glycol (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, isooctyloxydiethylene glycol (meth) acrylate, phenoxytriethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate, methoxy Examples include polyethylene glycol (meth) acrylate.

  Examples of the compound (b12) having one unsaturated group and at least one carboxyl group in one molecule include (meth) acrylic acid, and a modified unsaturated monoester having a chain extended between the unsaturated group and the carboxylic acid. Carboxylic acid, β-carboxyethyl (meth) acrylate, 2-acryloyloxyethyl succinic acid, 2-acryloyloxyethyl hexahydrophthalic acid, unsaturated monocarboxylic acid having an ester bond due to lactone modification, etc. Examples thereof include compounds having two or more carboxyl groups in one molecule such as saturated monocarboxylic acid and maleic acid. One type of the compound (b12) may be used, or two or more types of compounds (b12) may be used.

  Examples of the compound (b2) having an oxirane ring and an ethylenically unsaturated group in one molecule include glycidyl (meth) acrylate, α-methylglycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, Examples include 3,4-epoxycyclohexylethyl (meth) acrylate, 3,4-epoxycyclohexylbutyl (meth) acrylate, and 3,4-epoxycyclohexylmethylaminoacrylate. Of these, 3,4-epoxycyclohexylmethyl (meth) acrylate is preferable. 1 type of compounds (b2) may be used and 2 or more types of compounds (b2) may be used.

  The acid value of the carboxyl group-containing resins (i) to (iv) is preferably in the range of 50 to 150 mgKOH / g. When the acid value is in the range of 50 to 150 mgKOH / g, the resolution during development can be increased.

  Compound (i) contains a polymerizable hydrocarbon polymer having one or more unsaturated double bond groups and two or more carboxyl groups or acid anhydride groups, and has an acid value of 50 to 150 mgKOH / g. More preferably. The resolution during development can be increased.

  In addition, the “acid value” mentioned here is specifically determined by dissolving the compound in a solvent (toluene / 2-propanol / water (5/5 / 0.05 by volume)) and using potassium hydroxide. It can be calculated by Japanese titration. Examples of the neutralization titration method include a P-naphtholbenzein indicator method and a potentiometric titration method.

  Moreover, it is more preferable that the polymerizable hydrocarbon polymer includes an epoxy resin. For example, heterocyclic epoxy resins such as bisphenol S type epoxy resin, diglycidyl phthalate resin, triglycidyl isocyanurate, bixylenol type epoxy resin, biphenol type epoxy resin, tetraglycidyl xylenoylethane resin, bisphenol A type epoxy resin, Hydrogenated bisphenol A type epoxy resin, bisphenol F type resin, brominated bisphenol A type epoxy resin, phenol novolac type or cresol novolac type epoxy resin, alicyclic epoxy resin, bisphenol A novolak type epoxy resin, chelate type epoxy resin, Glyoxal type epoxy resin, amino group-containing epoxy resin, rubber modified epoxy resin, dicyclopentadiene phenolic type epoxy resin, silicone modified epoxy resin, ε-ca Rorakuton modified epoxy resins. One type of epoxy resin may be used, or two or more types of epoxy resins may be used in combination.

[Compound (B) having at least two cyclic ether groups in one molecule]
The photosensitive composition according to the present invention contains a compound having at least two cyclic ether groups in one molecule. As the compound (B) having such a cyclic ether group, dicyclopentadiene dioxide, (3,4-epoxycyclohexyl) methyl-3,4-epoxycyclohexanecarboxylate, bis (2,3-epoxycyclopentyl) ether Bis (3,4-epoxycyclohexylmethyl) adipate, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, (3,4-epoxy-6-methylcyclohexyl) methyl-3,4-epoxy-6 -Methylcyclohexanecarboxylate, bis (3,4-epoxycyclohexylmethyl) acetal, bis (3,4-epoxycyclohexyl) ether of ethylene glycol, bis (3,4-epoxycyclohexylmethyl) ether of ethylene glycol, ethyl 3,4-epoxycyclohexanecarboxylic acid diester of 2-glycol, 2- (3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy) cyclohexane-meta-dioxane, bisphenol A type epoxy resin, bisphenol F type Epoxy resin, bisphenol AD type epoxy resin, epoxy resin having hydantoin type, triglycidyl isocyanurate, polyphenols such as catechol and resorcinol or glycerin, glycidyl ether obtained by reacting polyhydric alcohol such as polyethylene glycol and epichlorohydrin, Polyglycidyl ester obtained by reacting polycarboxylic acid such as phthalic acid or isophthalic acid with epichlorohydrin, epoxidized phenol novolac resin, epoxidation Li olefin, water-soluble epoxy resin, or the like other urethane-modified epoxy resin.

  When the photopolymerization initiator is activated by light irradiation, the compound (B) having the cyclic ether group reacts with the polymerizable hydrocarbon monomer or polymer (A) to cure the photosensitive composition.

  The compound (B) having a cyclic ether group preferably reacts at a ratio of 0.1 to 50 parts by weight, more preferably at a ratio of 1 to 30 parts by weight with respect to 100 parts by weight of the compound (A). Blended. When the compounding ratio of the compound (B) having a cyclic ether group is within the above preferred range, a resist film that is difficult to discolor even when exposed to high temperatures can be obtained.

  Only 1 type may be used for the compound which has the said cyclic ether group, and 1 or more types may be used in combination.

[Polymerization initiator (C)]
Examples of the photopolymerization initiator (C) include acylphosphine oxide, halomethylated triazine, halomethylated oxadiazole, imidazole, benzoin, benzoin alkyl ether, anthraquinone, benzanthrone, benzophenone, acetophenone, thioxanthone, benzoate, Examples include acridine, phenazine, titanocene, α-aminoalkylphenone, oxime, and derivatives thereof. 1 type of photoinitiators (C) may be used and 2 or more types of photoinitiators (C) may be used.

  The photopolymerization initiator (C) is contained in the range of 0.1 to 30 parts by weight with respect to 100 parts by weight of the total of the transparent polymerizable hydrocarbon monomer and the transparent polymerizable hydrocarbon polymer. It is more preferable that it is contained within the range of 1 to 15 parts by weight. When the photopolymerization initiator (C) is contained within the above preferred range, the photosensitivity of the photosensitive composition can be further enhanced.

[(D) Amine compound (D1) represented by formula (1) or phosphine compound (D2) represented by formula (2)]
The photosensitive composition concerning this invention contains the compound (D) which is the phosphine compound (D2) represented by the amine compound (D1) represented by following formula (1), or Formula (2).

In Formula (1) or Formula (2), R _{1 to} R ₆ are a hydrogen atom, a hydrocarbon group, or an organic group containing an oxygen atom. R _{1 to} R ₆ may be the same or different.

In Formula (1) or Formula (2), R _{1 to} R ₆ are preferably a chain hydrocarbon group having 2 to 20 carbon atoms or an alicyclic hydrocarbon group having 6 to 12 carbon atoms, in which case The compound (D1) or the compound (D2) reacts with the compound (B) having the above cyclic ether group to generate a hydroxyl group. Due to this hydroxyl group, the adhesion of the finally obtained resist film to the substrate is enhanced. Therefore, even when exposed to a high temperature, a resist film can be obtained in which the adhesion to the substrate is hardly further lowered.

More preferably, R _{1 to} R ₆ are an ethyl group, an n-propyl group, an n-butyl group, or a cyclohexyl group, and in this case, the compound (D) is the above compound (B) having a cyclic ether group. Therefore, the developability of the resist film can be improved.

Examples of the chain hydrocarbon group having 2 to 20 carbon atoms include an ethyl group, an n-propyl group, an n-butyl group, a hexyl group, an octyl group, a pentyl group, a decyl group, a dodecyl group, a tetradecyl group, a hexadecyl group, and an octadecyl group. Is mentioned. Examples of the alicyclic hydrocarbon group having 3 to 12 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclooctyl group, and a norbornyl group. More preferably, R _{1 to} R ₆ are an ethyl group, an n-propyl group, an n-butyl group, or a cyclohexyl group.

  Specific examples of the compound (D) include n, n-dimethylbenzylamine, diphenylmethylphosphine, triphenylamine, triphenylphosphine, triethylamine, and tricyclohexylphosphine.

  The compound (D) is preferably blended at a ratio of 0.01 to 5 parts by weight with respect to a total of 100 parts by weight of the compound (A) and the compound (B). When the compounding ratio of the compound (D) is within this range, the adhesion of the finally obtained resist film to the substrate can be sufficiently increased, and the developability of the resist film can be further enhanced.

  If it is less than 0.01 part by weight, the adhesion may be lowered, and if it exceeds 5 parts by weight, the developability may be lowered.

[Inorganic filler (E)]
The photosensitive composition according to the present invention may contain an inorganic filler. Such inorganic fillers include calcium carbonate, aluminum oxide, aluminum hydroxide, zinc hydroxide, zinc oxide, aluminum nitride, silicon nitride, boron nitride, diamond powder, zirconium silicate, zirconium oxide, talc, barium sulfate, titanium. Examples thereof include barium acid, titanium oxide, clay, magnesium carbonate, magnesium hydroxide, mica, mica powder, lead sulfate, zinc sulfide, antimony oxide, titanium nitride, cerium fluoride, and cerium oxide.

  In addition, it is preferable that the pH measured by the boiling method is 6.8 or more and 11 or less, and in that case, the inorganic filler can further suppress yellowing of the resist film. More preferably, it is pH 7.0 or more, More preferably, it is pH 7.4 or more, More preferably, it is pH 8.1 or more. Since the pot life of the photosensitive composition can be further improved, the pH measured by the boiling method of the inorganic filler is preferably 10.0 or less, and more preferably pH 9.0 or less.

  The boiling method is as follows: (a) A liquid obtained by adding 5 g of the above inorganic filler to 100 mL of pure water is heated and boiled for 5 minutes, and then allowed to stand until reaching 23 ° C. to obtain a boiling treatment liquid ( b) Next, it is a method of measuring the pH of the obtained liquid by adding the amount of water evaporated at the time of boiling to the obtained boiling treatment liquid and making the total amount 100 mL.

  In the boiling method, specifically, a solution obtained by adding 5 g of the inorganic filler to 100 mL of pure water is placed in a container having an opening. The liquid in the container is heated by heating the container, and the liquid in the container is boiled. Maintain boiling for 5 minutes after starting to boil. Thereafter, a stopper is attached to the opening of the container and left to reach 23 ° C. to obtain a boiling treatment liquid. The stopper is removed from the opening of the container, and the amount of water evaporated by boiling is added to the obtained boiling treatment liquid to make the amount of water 100 mL. A stopper is attached to the opening of the container, shaken for 1 minute, and allowed to stand for 5 minutes. In this way, a measurement liquid is obtained. The pH of the obtained measuring solution is JIS Z8802 7. Can be measured in accordance with the operation described in 1.

  Examples of the inorganic filler include titanium oxide, zirconium oxide, antimony oxide, zinc oxide, white lead, zinc sulfide, potassium titanate, and lead titanate. Of these, titanium oxide is preferable because it is easy to handle.

  The inorganic filler is preferably rutile titanium oxide. In the case of rutile titanium oxide, yellowing hardly occurs when the solder resist film is exposed to light.

  It is preferable that at least one inorganic filler is coated with a basic metal oxide or basic metal hydroxide so that the surface is made basic. It is preferable that the surface of the inorganic filler is basic because yellowing of the resist film at higher temperatures can be further suppressed.

  Examples of the basic metal oxide or basic metal hydroxide include metal compounds such as magnesium, zirconium, cerium, strontium, antimony, barium, and calcium. Especially, since the possibility of yellowing when exposed to high temperature can be reduced, it is preferable that the material covering the inorganic filler contains zirconium oxide.

  Examples of the method for coating the inorganic filler include a method in which the inorganic filler to be coated is dispersed in water or a liquid medium containing water as a main component. At this time, preliminary pulverization may be performed using a wet pulverizer such as a sand mill or a ball mill according to the degree of aggregation of the inorganic filler. The pH of the slurry is preferably set as appropriate depending on the inorganic filler. For example, in the case of titanium oxide, the pH is preferably 9 or more. Next, a water-soluble salt of the metal to be coated is added to the slurry. Thereafter, neutralization, solid-liquid separation, drying and dry pulverization are performed, whereby a coated inorganic filler can be obtained.

  The inorganic filler preferably contains a compound capable of reacting with an acidic site of the inorganic filler in order to increase the basicity of the inorganic filler surface. Moreover, in order to raise the basicity of an inorganic filler, it is preferable to contain the inorganic filler in which the compound which can react with the acidic site | part of an inorganic filler exists on the surface. The compound capable of reacting with the acidic site of the inorganic filler includes (1) a polyhydric alcohol such as trimethylolpropane, trimethylolethane, ditrimethylolpropane, trimethylolpropane ethoxylate, or pentaerythritol, and (2) monoethanol. Examples thereof include alkanolamines such as amine, monopropanolamine diethanolamine, dipropanolamine, triethanolamine, and tripropanolamine, (3) chlorosilane, and (4) alkoxysilane.

  If the compound which can react with the acidic site | part of an inorganic filler is a basic compound, the basicity of an inorganic filler can be improved more and it is preferable. Examples of such preferable basic compound include alkanolamine.

  Surface treatment of the inorganic filler with a basic compound includes (1) a method of pulverizing the inorganic filler added with the above compound using a dry pulverizer such as a fluid energy pulverizer or an impact pulverizer, and (2) a Henschel mixer. And a method of stirring and mixing the inorganic filler after dry pulverization with the above compound using a high-speed stirrer such as a super mixer, and (3) a method of adding the above compound to an aqueous slurry of the inorganic filler and stirring. In particular, the method (1) is preferable because the inorganic filler can be pulverized and the surface treatment with the above compound can be simultaneously performed. As the dry pulverizer, a fluid energy pulverizer is preferable, and a swirl pulverizer such as a jet mill is more preferable.

  The content of the inorganic filler in 100% by weight of the photosensitive composition is preferably 3% by weight or more and 80% by weight or less. A more preferred lower limit is 10% by weight, and a more preferred upper limit is 75% by weight.

[Other ingredients]
The photosensitive composition according to the present invention includes an ultraviolet absorber, an antioxidant, a solvent, a colorant, a filler, an antifoaming agent, a curing agent, a curing accelerator, a release agent, a surface treatment agent, a flame retardant, and a viscosity modifier. An agent, a dispersant, a dispersion aid, a surface modifier, a plasticizer, an antibacterial agent, an antifungal agent, a leveling agent, a stabilizer, a coupling agent, an anti-sagging agent, or a phosphor may be contained.

[Preparation method]
The photosensitive composition according to the present invention can be prepared by, for example, stirring and mixing each compounding component and then uniformly mixing with three rolls.

Examples of the light source used for curing the photosensitive composition include an irradiation device that emits active energy rays such as ultraviolet rays or visible rays. Examples of the light source include an ultra high pressure mercury lamp, a deep UV lamp, a high pressure mercury lamp, a low pressure mercury lamp, a metal halide lamp, and an excimer laser. These light sources are appropriately selected according to the photosensitive wavelength of the constituent components of the photosensitive composition. The irradiation energy of light is appropriately selected depending on the desired film thickness or the constituent components of the photosensitive composition. The irradiation energy of light is generally in the range of 10 to 3000 mJ / cm ² .

[LED device]
The photosensitive composition concerning this invention is used suitably for formation of the soldering resist film in the LED device in which the LED chip is mounted in the board | substrate. FIG. 1 is a partially cutaway front sectional view schematically showing an LED device having a solder resist film formed using a photosensitive composition according to the present invention.

  In the LED device 1 shown in FIG. 1, a solder resist film 3 is formed on the upper surface 2 a of the substrate 2. An LED chip 7 is mounted on the solder resist film 3.

  The substrate 2 is composed of a laminated substrate having a glass layer 5 and a resin layer 6. But the board | substrate 2 is not specifically limited, Not only the laminated board which consists of resin and another material, You may form with other laminated boards, such as a ceramic multilayer board | substrate. Further, the substrate 2 may be a resin substrate made of a single resin material. Electrodes 4 a and 4 b are formed on the upper surface 2 a of the substrate 2. The electrodes 4a and 4b are made of an appropriate metal or alloy.

  The solder resist film 3 is formed by applying the photosensitive composition of the present invention onto the upper surface 2a of the substrate 2, and exposing and developing. More specifically, after forming the electrodes 4 a and 4 b, the photosensitive composition is applied to the entire surface of the upper surface 2 a of the substrate 2. Next, the photosensitive composition is selectively exposed from above using a mask in which the portions where the electrodes 4a and 4b are located are light shielding portions. The photosensitive composition is cured in a region irradiated with light by exposure. Curing of the photosensitive composition does not proceed in the region covered with the light shielding part. Therefore, the unexposed photosensitive composition portion is removed using a solvent that dissolves the uncured photosensitive composition. In this way, the solder resist film 3 having the openings 3a and 3b shown in FIG. 1 can be obtained. The electrodes 4a and 4b are exposed in the openings 3a and 3b, respectively.

  Next, the LED chip 7 having the terminals 8a and 8b on the lower surface 7a is mounted on the solder resist film 3, and the terminals 8a and 8b and the electrodes 4a and 4b are joined by solders 9a and 9b, respectively. In this way, the LED device 1 is obtained.

  In the LED device 1, when the LED chip 7 is driven, light is emitted as indicated by a broken line. In this case, not only the light irradiated from the LED chip 7 to the side opposite to the upper surface 2 a of the substrate 2, that is, the light irradiated on the solder resist film 3 is reflected as shown by the arrow A. The solder resist film 3 is white and reflects the light with high efficiency. Therefore, since the reflected light indicated by the arrow A is also used, the light use efficiency of the LED chip 7 can be increased.

  Hereinafter, the effects of the present invention will be clarified by giving specific examples and comparative examples of the present invention.

  First, evaluation methods of Examples and Comparative Examples will be described.

(Evaluation methods)
(1) Preparation of measurement sample On a glass epoxy substrate having a size of 80 mm × 90 mm × thickness 0.8 mm, a product number: FR-4, using a 100-mesh polyester bias screen printing plate by a screen printing method, The photosensitive composition was printed on the entire surface. After printing, the photosensitive composition layer printed for 20 minutes in an oven at 80 ° C. was dried. Next, using a UV irradiation device, UV light having a wavelength of 365 nm is applied to the photosensitive composition layer through a photomask having a pattern in which an unexposed area is a light-shielding portion so that the irradiation energy is 400 mJ / cm ^2. Irradiation with ultraviolet illuminance of 100 mW / cm ² for 4 seconds. Curing with ultraviolet light progressed, and a white resist film was formed. After irradiation, the resist film was immersed in a 1% by weight aqueous solution of sodium carbonate and developed to remove the unexposed photosensitive composition layer portion. In this way, a resist film having a pattern in which the light shielding part is an opening was obtained. Thereafter, the resist film was heated and cured in an oven at 150 ° C. for 1 hour to obtain a sample on which the resist film was formed. In addition, the thickness of the resist film in the obtained sample was 20 μm.

(2) Heat resistance The sample obtained in (1) was placed in a heating oven and heated at 270 ° C for 5 minutes.

  Using a color / color difference meter (CR-400, manufactured by Konica Minolta Co., Ltd.), L *, a *, and b * of the sample before heat treatment were measured. Further, L *, a *, and b * of the evaluation sample after the heat treatment were measured, and ΔE * ab was obtained from these two measured values.

[Evaluation criteria for yellowing degree]
ΔE * ab of the heat-treated sample is “◎” when it is 2 or less, exceeds 2 and is “◯” when it is 3 or less, “△” when 3 or less and 3.5 or less, “Δ”, 3 The results are shown in Table 1 below, where.

[Evaluation criteria for heat-resistant adhesion]
In the obtained sample, the adhesion of the resist film to the substrate was evaluated. In accordance with JIS K5600, using a cutter, the resist film on the substrate was cut so as to have a size of 1 mm × 1 mm when viewed in plan, and the resist film was divided into 100 pieces. An adhesive tape (cellophane tape, LP-18, manufactured by Nichiban Co., Ltd.) was attached to the divided resist film, and the adhesive tape was peeled off together with the resist film, and peeling was attempted. Whether the resist film was peeled off together with the tape was observed, and the adhesion was evaluated according to the following evaluation criteria.

◎: 100 resist films that did not peel out of 100 divided resist films ○: 90 to 99 resist films that did not peel out of 100 divided resist films Δ: Divided resist film 80 to 89 resist films that did not peel out of 100 pieces ×: 0 to 79 resist films that did not peel out of 100 divided resist films

(3) Developability A copper circuit having a thickness of 40 μm was formed on the upper surface, and a printed wiring board of 80 mm × 90 mm × thickness 1.0 mm was prepared. The photosensitive composition was screen-printed on the entire upper surface of the printed wiring board using a 100-mesh polyester bias screen plate. Thereafter, the photosensitive composition layer printed in a hot air oven at 80 ° C. was dried for 20 minutes.

Next, the photosensitive composition layer was selectively irradiated with ultraviolet rays through a photomask having a light shielding portion. Specifically, using an ultraviolet irradiation device (HMW-680GX, manufactured by Oak Manufacturing Co., Ltd.), ultraviolet rays having a wavelength of 365 nm are irradiated for 12 seconds at an ultraviolet illuminance of 50 mW / cm ² so that the irradiation energy is 600 mJ / cm ^2. Irradiated.

  Curing progressed in the photosensitive composition layer by irradiation with the ultraviolet rays, and a resist film was formed. This resist film was developed by using a 1 wt% sodium carbonate aqueous solution at 30 ° C. as a developing solution, being immersed for 90 seconds under a pressure of 0.2 MPa, and then dried in a hot air oven at 150 ° C. for 60 minutes. Thus, a resist film having a thickness of 20 μm was obtained. This resist film was used as a second sample.

  When obtaining the resist film of the second sample, whether or not a pattern was formed after development was observed using an electron microscope, and developability was evaluated according to the following evaluation criteria.

〔Evaluation criteria〕
○: L / S 100 μm pattern was formed Δ: L / S 100 μm pattern was formed, but there was a variation of 10% or more in the length direction dimension of the pattern ×: L / S 100 μm The pattern was not formed

(Synthesis Example 1) (Acrylic polymer 1)
A flask equipped with a thermometer, stirrer, dropping funnel, and reflux condenser is charged with ethyl carbitol acetate as a solvent and azobisisobutyronitrile as a catalyst, heated to 80 ° C. in a nitrogen atmosphere, methacrylic acid and methyl A monomer in which methacrylate was mixed at a molar ratio of 30:70 was dropped over about 2 hours. After stirring for another hour, the temperature was raised to 120 ° C.

  After cooling this solution to room temperature, 1 g of tetrabutylammonium bromide was added as a catalyst, and glycidyl acrylate was added so as to have a molar ratio of 10 to 100 in total of methacrylic acid and methyl acrylate. The resulting resin was subjected to an addition reaction with an equivalent amount of carboxyl groups, and then cooled to room temperature. The solution was taken out from the flask after cooling. When this solution was analyzed, it was confirmed that the acid value of the solid content was 60 mg KOH / g and the solution contained 50% by mass (nonvolatile content) of a carboxyl group-containing resin having a weight average molecular weight of 15,000. This solution is hereinafter referred to as acrylic polymer 1.

(Synthesis Example 2) (Acrylic polymer 2)
750 g of dipropylene glycol monomethyl ether and 17.9 g of t-butylperoxy 2-ethylhexanoate were charged, and after raising the temperature to 95 ° C., 241.4 g of methacrylic acid, succinic acid-modified ε-caprolactone-modified 2-hydroxyethyl methacrylate ( 205.4 g of Daicel Chemical Industries, Ltd. Plaxel FM1A) was added dropwise to dipropylene glycol monomethyl ether together with 17.9 g of 2,2′-azobis- (2,4-dimethylvaleronitrile) over 3 hours. By aging for a time, a vinyl copolymer solution having a carboxyl group was obtained. The reaction was performed under a N ₂ stream. Next, 303.3 g of epoxy cyclohexyl methyl acrylate (Daicel Chemical Industries, Ltd. Cyclomer A200), 3.03 g of triphenylphosphine, and 1.5 g of hydroquinone monomethyl ether were added to the vinyl copolymer solution, and the temperature was raised to 100 ° C. Then, epoxy ring-opening addition reaction was carried out by stirring. The reaction was performed under an air stream.

  After 10 hours, the contents were removed and the solution of the contents was analyzed. As a result, it was confirmed that this was an unsaturated group-containing curable resin solution having an acid value of 76.5 mgKOH / g, a solid content concentration of 55%, and a weight average molecular weight of 20000. Hereinafter, this resin solution is referred to as acrylic polymer 2.

Example 1
15 parts by weight of acrylic polymer 1, 5 parts by weight of dipentaerythritol hexaacrylate (DPHA), 40 parts by weight of rutile type titanium oxide (D-918, manufactured by Sakai Chemical Co., Ltd.), photo radical polymerization initiator (TPO, Japan) 2 parts by weight of Siebel Hegner), bisphenol A type epoxy resin (828, Japan Epoxy Resin) and 0.1 part by weight of N, N-dimethylbenzylamine are blended, and a blender (Nertaro SP-500, Sinky) After mixing for 3 minutes, the mixture was mixed with 3 rolls. Then, the photosensitive composition was obtained by defoaming the mixture for 3 minutes using a mixer (SP-500, manufactured by Sinky Corporation).

  The obtained photosensitive composition was coated on a substrate made of FR-4 by a screen printing method. After coating, the resist material layer was formed on the substrate by drying in an oven at 80 ° C. for 20 minutes. Next, using a UV irradiator through a photomask having a predetermined pattern, UV light having a wavelength of 365 nm is applied to the resist material layer for 4 seconds at an ultraviolet illuminance of 100 mW / cm 2 so that the irradiation energy is 400 mJ / cm 2. Irradiated. After irradiating with ultraviolet rays, the resist material layer was immersed in a 1% by weight aqueous solution of sodium carbonate and developed, and the resist material layer in the unexposed area was removed to form a resist film pattern on the substrate. Thereafter, the resist film was post-cured by heating in an oven at 150 ° C. for 1 hour to obtain a resist film. The thickness of the obtained resist film was 20 μm.

(Examples 2-8 and Comparative Examples 1-2)
A photosensitive composition was prepared in the same manner as in Example 1 except that the composition was changed to the composition described in Table 1.

  As is clear from Table 1, the examples including the formula (1) or the formula (2) have higher heat resistance than the comparative example 1 even when exposed to high temperatures. This is considered that the discoloration of the resist film is caused by a coloring substance generated from a peroxide or the like generated in a high temperature environment (use conditions), and is shown in the above formulas (1) and (2). Since the compound is a Lewis base, it has a function of decomposing the peroxide. Accordingly, it is considered that a resist film that hardly changes color can be obtained because the colored substance generated from the peroxide is decomposed. In addition, the Lewis base promotes the curing reaction between the polymerizable hydrocarbon monomer or polymer having at least one carboxyl group in one molecule and the compound having two or more cyclic ether groups in one molecule. As a result, it is considered that the resist film is hardly discolored as a result of an increase in the crosslink density of the resist film.

Moreover, as is clear from Examples 2 and 3, R _{1 to} R ₆ are hydrocarbons that may have 2 to 20 carbon atoms, and fats that may have 3 to 12 carbon atoms. When it is a cyclic hydrocarbon, the compound (D) represented by the formulas (1) and (2) reacts with the compound (B) having two or more cyclic ether groups in one molecule to generate a hydroxyl group. To do. It is considered that due to the adhesion improvement effect by the hydroxyl group, the adhesion of the resist film to the substrate is hardly lowered even when exposed to a high temperature.

Further, as is clear from Examples 4 and 5, when R _{1 to} R ₆ are an ethyl group, an n-propyl group, an n-butyl group, or a cyclohexyl group, they are represented by formulas (1) and (2). Since the compound (D) to be reacted appropriately with the compound having two or more cyclic ether groups in one molecule, the developability is considered to be improved.

  As is clear from Examples 7 and 8, when an inorganic filler having a pH of 6.8 or more and 11 or less is included, Lewis of the compound (D) represented by the above formula (1) or (2) As the basicity further increases, a curing reaction with a compound having two or more cyclic ether groups in one molecule proceeds, and the crosslink density of the resist film is increased. As a result, a resist film that is more difficult to discolor is obtained. It is thought that it was possible.

DESCRIPTION OF SYMBOLS 1 ... LED device 2 ... Board | substrate 2a ... Upper surface 3 ... Solder resist film 3a, 3b ... Opening part 4a, 4b ... Electrode 5 ... Glass layer 6 ... Resin layer 7 ... LED chip 7a ... Lower surface 8a, 8b ... Terminal 9a, 9b ... solder

Claims (6)

(A) at least one polymerizable hydrocarbon compound of a polymerizable hydrocarbon monomer having at least one carboxyl group in one molecule and a polymerizable hydrocarbon polymer;
(B) a compound having at least two cyclic ether groups in one molecule;
(C) a photopolymerization initiator;
(D) A photosensitive composition comprising an amine compound represented by the following formula (1) or a phosphine compound represented by the following formula (2).

In (Equation (1) or Formula _(2), R 1 to R ₆ is a hydrogen atom, a one selected from the group consisting of an organic group containing a hydrocarbon group and an oxygen _atom, R 1 to R ₆ is They may be the same or different) Wherein R ₁ to R ₆ is an alicyclic hydrocarbon group having a chain hydrocarbon group or a 3 to 12 carbon atoms having 2 to 20 carbon atoms, photosensitive composition according to claim 1. Wherein R ₁ to R ₆ is an ethyl group, an n- propyl group, one hydrocarbon group selected from the group consisting of n- butyl and cyclohexyl, photosensitive composition according to claim 2.   The photosensitive composition according to any one of claims 1 to 3, further comprising an inorganic filler having a pH of 6.8 or more and 11 or less.   The said compound (D) is 0.01-5 weight part with respect to a total of 100 weight part of the said compound (A) and the said compound (B), The any one of Claims 1-4 containing. Photosensitive composition. The soldering resist composition which consists of the photosensitive composition of any one of Claims 1-5.

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