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WO2020066489A1 - Solder composition and electronic substrate - Google Patents

Solder composition and electronic substrate Download PDF

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Publication number
WO2020066489A1
WO2020066489A1 PCT/JP2019/034542 JP2019034542W WO2020066489A1 WO 2020066489 A1 WO2020066489 A1 WO 2020066489A1 JP 2019034542 W JP2019034542 W JP 2019034542W WO 2020066489 A1 WO2020066489 A1 WO 2020066489A1
Authority
WO
WIPO (PCT)
Prior art keywords
component
solder
acid
mass
solder composition
Prior art date
Application number
PCT/JP2019/034542
Other languages
French (fr)
Japanese (ja)
Inventor
弘 榮西
伸一 臼倉
慎二 吉澤
岩渕　充
Original Assignee
株式会社タムラ製作所
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2019159582A external-priority patent/JP6940565B2/en
Application filed by 株式会社タムラ製作所 filed Critical 株式会社タムラ製作所
Priority to CN201980001737.6A priority Critical patent/CN111225764A/en
Priority to EP19866061.5A priority patent/EP3858538A4/en
Publication of WO2020066489A1 publication Critical patent/WO2020066489A1/en

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
    • B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
    • B23K35/24—Selection of soldering or welding materials proper
    • B23K35/26—Selection of soldering or welding materials proper with the principal constituent melting at less than 400 degrees C
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C13/00—Alloys based on tin

Definitions

  • the present invention relates to a solder composition and an electronic substrate.
  • the solder composition is a mixture obtained by kneading a flux composition (a rosin-based resin, an activator, a solvent, and the like) with a solder powder to form a paste (for example, Patent Document 1).
  • a flux composition a rosin-based resin, an activator, a solvent, and the like
  • solder powder for example, Patent Document 1
  • solderability such as solder melting property and a property that solder easily spreads (solder wet spreading)
  • suppression of voids and printability are required.
  • large-sized electronic components have been mounted on electronic substrates. Further, among large electronic components, there are electronic components having a large electrode terminal area (for example, QFN (Quad Flatpack No Lead), power transistor). In such an electronic component, the printed area of the solder composition is large, so that voids tend to be easily generated.
  • an object of the present invention is to provide a solder composition that can sufficiently suppress voids, and an electronic substrate using the same.
  • the solder composition of the present invention comprises: (A) a flux composition containing a rosin-based resin, (B) an activator, and (C) a solvent, and (D) a solder powder having a melting point of 200 ° C. or more and 250 ° C. or less.
  • (B1) an aromatic carboxylic acid having a hydroxyl group only at the ortho or pros position
  • (B2) a dicarboxylic acid having an alkylene group and having 2 to 8 carbon atoms
  • B3) An alkyl group, containing at least one member selected from the group consisting of monocarboxylic acids having 2 to 8 carbon atoms, wherein the component (C) is (C1) having a boiling point of 220 ° C or higher and 250 ° C or lower. Which is characterized by containing a diol or a diacetate of a diol.
  • the component (C1) comprises 1,4-butanediol, 1,5-pentanediol, 2-ethyl-1,3-hexanediol, 1,2-hexanediol, dipropylene It is preferably at least one selected from the group consisting of glycol, 1,4-butanediol diacetate, and 1,3-butylene diol diacetate.
  • the component (C1) preferably has a boiling point of 230 ° C. or more and 250 ° C. or less.
  • the component (B) preferably further contains (B4) dimer acid.
  • An electronic substrate according to the present invention includes a soldered portion using the solder composition.
  • the reason why voids can be sufficiently suppressed is not always clear, but the present inventors speculate as follows. That is, in the solder composition of the present invention, (C1) a diol or a diol diacetate having a boiling point of 220 ° C. or more and 250 ° C. or less is used as the solvent (C). Part of the component (C1) is volatilized before the solder is melted or when the solder is melted and becomes a gas. This gas has an effect of pushing out the gas in the solder composition to the outside.
  • the solder composition containing the component (C1) that has not volatilized has a certain degree of fluidity even when the solder is melted, the gas in the solder composition is gradually collected and released to the outside. In this way, voids can be sufficiently suppressed. In addition, depending on the type of the organic acid, it can be a factor for generating voids. On the other hand, in the present invention, an organic acid (such as the component (B1)) which does not easily cause voids is selected and used. The present inventors presume that the effects of the present invention are achieved as described above.
  • solder composition capable of sufficiently suppressing voids and an electronic substrate using the same can be provided.
  • the solder composition of the present invention contains a flux composition described below and a solder powder (D) described below.
  • the flux composition used in the present invention is a component other than the solder powder in the solder composition, and contains (A) a rosin-based resin, (B) an activator, and (C) a solvent.
  • the rosin-based resin (A) used in the present embodiment includes rosins and rosin-modified resins. Rosins include gum rosin, wood rosin and tall oil rosin. Examples of the rosin-based modified resin include disproportionated rosin, polymerized rosin, hydrogenated rosin, and derivatives thereof. Examples of the hydrogenated rosin include fully hydrogenated rosin, partially hydrogenated rosin, and unsaturated organic acids (such as aliphatic unsaturated monobasic acids such as (meth) acrylic acid), ⁇ , ⁇ - such as fumaric acid and maleic acid.
  • Rosins include gum rosin, wood rosin and tall oil rosin.
  • the rosin-based modified resin include disproportionated rosin, polymerized rosin, hydrogenated rosin, and derivatives thereof.
  • Examples of the hydrogenated rosin include fully hydrogenated rosin, partially hydrogenated rosin, and unsaturated organic acids (such as aliphatic unsaturated
  • a hydrogenated product of an unsaturated organic acid-modified rosin that is a modified rosin of an aliphatic unsaturated dibasic acid such as an unsaturated carboxylic acid, an unsaturated carboxylic acid having an aromatic ring such as cinnamic acid, etc. Rosin).
  • These rosin-based resins may be used alone or in a combination of two or more.
  • the amount of the component (A) is preferably from 20% by mass to 70% by mass, more preferably from 30% by mass to 60% by mass, based on 100% by mass of the flux composition.
  • the amount of the component (A) is not less than the lower limit, it is possible to prevent the oxidation of the copper foil surface of the soldering land and to easily wet the molten solder on the surface. Can be suppressed.
  • the amount of the component (A) is equal to or less than the upper limit, the amount of flux residue can be sufficiently suppressed.
  • the activator (B) used in this embodiment includes (B1) an aromatic carboxylic acid having a hydroxyl group only at the ortho or pros position, (B2) a dicarboxylic acid having an alkylene group and having 2 to 8 carbon atoms, and , (B3) having an alkyl group and containing at least one member selected from the group consisting of monocarboxylic acids having 2 to 8 carbon atoms. These components (B1) to (B3) hardly cause voids.
  • Examples of the component (B1) include 2,6-dihydroxybenzoic acid, 2-hydroxybenzoic acid, 1-hydroxy-2-naphthoic acid, and 3-hydroxy-2-naphthoic acid. Among these, 2,6-dihydroxybenzoic acid is particularly preferred. These may be used alone or as a mixture of two or more.
  • Examples of the component (B2) include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, and suberic acid. Among these, succinic acid, glutaric acid and adipic acid are preferred, and succinic acid and adipic acid are more preferred. These may be used alone or as a mixture of two or more.
  • the component (B3) examples include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, and caprylic acid. These may be used alone or as a mixture of two or more.
  • the components (B1) to (B3) the components (B1) and (B2) are more preferable, and the component (B1) is particularly preferable, from the viewpoint of voids and active action.
  • the total blending amount of the components (B1) to (B3) is preferably 1% by mass or more and 7% by mass or less with respect to 100% by mass of the flux composition, from the viewpoint of voids and active action. It is more preferably from 5% by mass to 5% by mass, particularly preferably from 2% by mass to 3% by mass.
  • the component (B) may further contain (B4) dimer acid. Since the component (B4) tends to prevent reoxidation of the solder powder, the action of another activator can be synergistically enhanced.
  • the component (B4) hardly causes voids.
  • the component (B4) is preferably a dimer acid produced by polymerization of an unsaturated fatty acid.
  • the carbon number of the unsaturated fatty acid is not particularly limited, but is preferably 8 or more and 22 or less, more preferably 12 or more and 18 or less, and particularly preferably 18.
  • the dimer acid may be one having a dibasic acid as a main component (50% by mass or more), and may contain a monobasic acid or a tribasic acid.
  • an organic acid other than the components (B1) to (B4) it is preferable not to use an organic acid other than the components (B1) to (B4) from the viewpoint of suppressing chip side balls and voids.
  • the blending amount of the component (B4) is preferably from 1% by mass to 20% by mass, and more preferably from 3% by mass to 15% by mass, based on 100% by mass of the flux composition, from the viewpoint of voids and activating action. It is more preferable that the content is 5% by mass or more and 10% by mass or less.
  • the component (B) includes, in addition to the components (B1) to (B4), other activators ((B5) a halogen-based activator and (B6) an amine-based activator) as long as the object of the present invention can be achieved. ) May be further contained.
  • the total amount of the components (B1) to (B4) is preferably 90% by mass or more, and more preferably 95% by mass or more based on 100% by mass of the component (B) from the viewpoint of voids and active action. Is more preferable.
  • the component (B5) may be a compound formed by a covalent bond of each of chlorine, bromine, and fluorine, such as chlorinated, brominated, and fluoride, or any two or all of chlorine, bromine, and fluorine. May be a compound having a covalent bond of These compounds preferably have a polar group such as a hydroxyl group or a carboxyl group like a halogenated alcohol or a halogenated carboxyl compound in order to improve solubility in an aqueous solvent.
  • a polar group such as a hydroxyl group or a carboxyl group like a halogenated alcohol or a halogenated carboxyl compound in order to improve solubility in an aqueous solvent.
  • halogenated alcohol examples include brominated alcohols (2,3-dibromopropanol, 2,3-dibromobutanediol, trans-2,3-dibromo-2-butene-1,4-diol, 1,4-dibromo -2-butanol, tribromoneopentyl alcohol, etc.), chlorinated alcohols (1,3-dichloro-2-propanol, 1,4-dichloro-2-butanol, etc.), fluorinated alcohols (3-fluorocatechol, etc.) ), And other similar compounds.
  • halogenated carboxyl compound examples include iodide carboxyl compounds (such as 2-iodobenzoic acid, 3-iodobenzoic acid, 2-iodopropionic acid, 5-iodosalicylic acid, and 5-iodoanthranilic acid), and carboxyl chloride compounds (2- Chlorobenzoic acid, 3-chloropropionic acid, etc.), brominated carboxyl compounds (2,3-dibromopropionic acid, 2,3-dibromosuccinic acid, 2-bromobenzoic acid, etc.), and other similar compounds Is mentioned. In addition, these may be used individually by 1 type, and may be used in mixture of 2 or more types.
  • iodide carboxyl compounds such as 2-iodobenzoic acid, 3-iodobenzoic acid, 2-iodopropionic acid, 5-iodosalicylic acid, and 5-iodoanthranilic acid
  • amines eg, polyamines such as ethylenediamine
  • amine salts eg, amines such as trimethylolamine, cyclohexylamine, and diethylamine
  • organic acid salts and inorganic acid salts such as aminoalcohols (hydrochloric acid, sulfuric acid, and the like) Hydrobromic acid
  • amino acids such as glycine, alanine, aspartic acid, glutamic acid, and valine
  • amide compounds e.glycine, alanine, aspartic acid, glutamic acid, and valine
  • imidazole compounds e.g, imidazole compounds.
  • diphenylguanidine hydrobromide cyclohexylamine hydrobromide
  • diethylamine salt such as hydrochloride, succinate, adipate, and sebacate
  • triethanolamine monoethanolamine
  • monoethanolamine and hydrobromides of these amines.
  • the blending amount of the component (B) is preferably from 1% by mass to 25% by mass, more preferably from 2% by mass to 20% by mass, based on 100% by mass of the flux composition. It is particularly preferable that the content be from 15% by mass to 15% by mass.
  • the amount of the component (B) is less than the lower limit, solder balls tend to be easily formed.
  • the amount exceeds the upper limit the insulating property of the flux composition tends to decrease.
  • the (C) solvent used in the present embodiment needs to contain (C1) a diol or a diol diacetate having a boiling point of 220 ° C. or more and 250 ° C. or less.
  • the generation of voids can be suppressed by the component (C1).
  • a boiling point means the boiling point in 1013 hPa.
  • the boiling point of the component (C1) is preferably from 220 ° C to 240 ° C, more preferably from 225 ° C to 235 ° C, and more preferably from 230 ° C to 235 ° C. Particularly preferred.
  • 1,4-butanediol (boiling point: 230 ° C.), 1,5-pentanediol (boiling point: 240 ° C.), 2-ethyl-1,3-hexanediol (boiling point: 242 ° C.), 1,2-hexanediol (boiling point: 223 ° C.), dipropylene glycol (boiling point: 230 ° C.), 1,4-butanediol diacetate (boiling point: 232 ° C.), and 1,3-butylenediol diacetate (boiling point: 232 ° C.).
  • 1,4-butanediol and 1,3-butylenediol diacetate are more preferred from the viewpoint of the melting point of the solvent. These may be used alone or as a mixture of two or more.
  • Component (C) may contain a solvent (component (C2)) other than component (C1) as long as the object of the present invention can be achieved.
  • component (C2) diethylene glycol monohexyl ether, diethylene glycol monobutyl ether, ⁇ , ⁇ , ⁇ -terpineol, benzyl glycol, diethylene glycol mono-2-ethylhexyl ether, tripropylene glycol, diethylene glycol monobenzyl ether, diethylene glycol dibutyl ether, tripropylene glycol Monomethyl ether, dipropylene glycol monobutyl ether, ethylene glycol mono-2-ethylhexyl ether, diethylene glycol monoethyl ether acetate, 2,2-dimethyl-1,3-propanediol and the like can be mentioned. These may be used alone or as a mixture of two or more.
  • the mass ratio ((C2) / (C)) of the component (C2) to the component (C) is from 1/15 to 1/1, from the viewpoint of the balance between the suppression of voids and the printability. It is preferably 1 or less, more preferably 1/10 or more and ⁇ or less, particularly preferably 1/5 or more and 1/3 or less.
  • the compounding amount of the component (C) is preferably 20% by mass or more and 60% by mass or less, more preferably 25% by mass or more and 50% by mass or less, and more preferably 30% by mass or less with respect to 100% by mass of the flux composition. % To 40% by mass or less is particularly preferred. If the amount of the solvent is within the above range, the viscosity of the obtained solder composition can be appropriately adjusted to an appropriate range.
  • a thixotropic agent may be further contained from the viewpoint of printability and the like.
  • the thixotropic agent used in the present embodiment include hardened castor oil, amides, kaolin, colloidal silica, organic bentonite, and glass frit.
  • One of these thixotropic agents may be used alone, or two or more thereof may be used in combination.
  • the amount thereof is preferably 2% by mass or more and 20% by mass or less, more preferably 4% by mass or more and 12% by mass or less based on 100% by mass of the flux composition.
  • the amount is less than the lower limit, thixotropic properties are not obtained and sagging tends to occur.
  • the amount exceeds the upper limit the thixotropic properties are too high and printing tends to be poor.
  • additives and further other resins are added as necessary.
  • Other additives include defoamers, antioxidants, modifiers, matting agents, foaming agents, and the like.
  • the amount of these additives is preferably 0.01% by mass or more and 5% by mass or less based on 100% by mass of the flux composition.
  • Other resins include acrylic resins.
  • solder composition contains the above-described flux composition of the present embodiment and (D) a solder powder described below.
  • the compounding amount of the flux composition is preferably from 5% by mass to 35% by mass, more preferably from 7% by mass to 15% by mass, and more preferably 8% by mass, based on 100% by mass of the solder composition. It is particularly preferable that the content be at least 12 mass%.
  • the compounding amount of the flux composition is less than 5% by mass (when the compounding amount of the solder powder exceeds 95% by mass), the flux composition as a binder is insufficient, so that the flux composition and the solder powder are mixed.
  • the amount of the flux composition exceeds 35% by mass (when the amount of the solder powder is less than 65% by mass)
  • the obtained solder composition is used, It tends to be difficult to form a sufficient solder joint.
  • the solder powder (D) used in the present embodiment is a solder powder having a melting point of 200 ° C. or more and 250 ° C. or less.
  • the boiling point of the component (C1) is defined on the assumption that a solder powder having a melting point of 200 ° C. or more and 250 ° C. or less is used.
  • As a solder alloy in the solder powder an alloy containing tin (Sn) as a main component is preferable.
  • the second element of the alloy includes silver (Ag), copper (Cu), zinc (Zn), bismuth (Bi), indium (In), and antimony (Sb). Further, other elements (third and subsequent elements) may be added to this alloy as needed.
  • the lead-free solder powder refers to a solder metal or alloy powder to which lead is not added.
  • the presence of lead as an unavoidable impurity in the lead-free solder powder is acceptable, but in this case, the amount of lead is preferably 300 ppm by mass or less.
  • solder alloy in the lead-free solder powder examples include Sn-Ag and Sn-Ag-Cu.
  • Sn-Ag-Cu-based solder alloys are preferably used from the viewpoint of the strength of the solder joint.
  • the melting point of the Sn—Ag—Cu solder is usually 200 ° C. to 250 ° C. (preferably, 200 ° C. to 240 ° C.).
  • the solder having a low silver content has a melting point of 210 ° C. or more and 250 ° C. or less (preferably 220 ° C. or more and 240 ° C. or less).
  • the average particle diameter of the component (D) is usually 1 ⁇ m or more and 40 ⁇ m or less, but is preferably 1 ⁇ m or more and 35 ⁇ m or less, more preferably 2 ⁇ m or more and 30 ⁇ m or less, from the viewpoint of supporting an electronic substrate having a narrow solder pad pitch. It is still more preferable that the thickness is not more than 3 ⁇ m and particularly preferably not more than 3 ⁇ m and not more than 20 ⁇ m.
  • the average particle size can be measured by a dynamic light scattering type particle size measuring device.
  • solder composition manufacturing method The solder composition of the present embodiment can be manufactured by blending the above-described flux composition and the above-described (D) solder powder at the above-described predetermined ratio and stirring and mixing.
  • the electronic substrate according to the present embodiment includes a soldered portion using the above-described solder composition.
  • the electronic substrate of the present invention can be manufactured by mounting an electronic component on an electronic substrate (such as a printed wiring board) using the solder composition.
  • the above-described solder composition of the present embodiment can sufficiently suppress large-diameter voids even when the printed area of the solder composition is large. Therefore, an electronic component having a large electrode terminal area (for example, QFN, power transistor) may be used as the electronic component.
  • the printed area of the solder composition may be, for example, 20 mm 2 or more, 30 mm 2 or more, or 40 mm 2 or more.
  • the printing area corresponds to the area of the electrode terminal of the electronic component.
  • the coating device used here include a screen printing machine, a metal mask printing machine, a dispenser, and a jet dispenser.
  • the electronic component is placed on the solder composition applied by the coating device, heated by a reflow oven under predetermined conditions, and the electronic component is mounted on a printed wiring board by a reflow process. Can be implemented.
  • the electronic component is placed on the solder composition, and heated by a reflow furnace under predetermined conditions.
  • a sufficient solder joint can be performed between the electronic component and the printed wiring board.
  • the electronic component can be mounted on the printed wiring board.
  • the reflow condition may be appropriately set according to the melting point of the solder.
  • the preheat temperature is preferably from 140 ° C to 200 ° C, more preferably from 150 ° C to 160 ° C.
  • the preheating time is preferably from 60 seconds to 120 seconds.
  • the peak temperature is preferably from 230 ° C to 270 ° C, more preferably from 240 ° C to 255 ° C.
  • the holding time at a temperature of 220 ° C. or more is preferably 20 seconds or more and 60 seconds or less.
  • the solder composition and the electronic substrate of the present embodiment are not limited to the above embodiment, and modifications and improvements as long as the object of the present invention can be achieved are included in the present invention.
  • the printed wiring board and the electronic component are bonded by the reflow process, but the present invention is not limited to this.
  • the printed wiring board and the electronic component may be bonded to each other by a step of heating the solder composition using a laser beam (laser heating step).
  • the laser light source is not particularly limited, and can be appropriately adopted according to the wavelength adjusted to the absorption band of the metal.
  • a laser light source for example, a solid laser (ruby, glass, YAG, etc.), a semiconductor laser (GaAs, InGaAsP, etc.), a liquid laser (dye, etc.), and a gas laser (He—Ne, Ar, CO 2 , Excimer, etc.).
  • ((B4) component) Organic acid G: dimer acid, trade name "UNIDYME14", manufactured by Air Brown (component (B5))
  • Halogen activator trans-2,3-dibromo-2-butene-1,4-diol (TDBD)
  • (C1) component) Solvent A: 1,4-butanediol (boiling point: 230 ° C.)
  • solvent B 1,3-butylene diol diacetate (boiling point: 232 ° C.) manufactured by Tokyo Chemical Industry Co., Ltd.
  • solvent C 1,5-pentane manufactured by Daicel Chemical Industries, Ltd.
  • Diol (boiling point: 240 ° C.), solvent D: 2-ethyl-1,3-hexanediol (boiling point: 242 ° C.) manufactured by Tokyo Kasei Co., Ltd.
  • Solvent E 1,4-butanediol diacetate (boiling point: manufactured by Nippon Emulsifier) 232 ° C.), trade name “CELTOL 1,4-BDDA”, solvent F manufactured by Daicel Chemical Industries, Ltd .: dipropylene glycol (boiling point: 230 ° C.), solvent G manufactured by Tokyo Kasei Co., Ltd., 1,2-hexanediol (boiling point: 223 ° C.) ), Manufactured by Osaka Organic Chemical Industry Co., Ltd.
  • Example 1 Container containing 46% by mass of rosin-based resin, 2% by mass of organic acid A, 8.5% by mass of organic acid G, 0.5% by mass of halogen-based activator, 35% by mass of solvent A, 6% by mass of thixotropic agent and 2% by mass of antioxidant And mixed using a planetary mixer to obtain a flux composition. Thereafter, 11% by mass of the obtained flux composition and 89% by mass of solder powder (100% by mass in total) were charged into a container, and mixed by a planetary mixer to prepare a solder composition.
  • Examples 2 to 12 A solder composition was obtained in the same manner as in Example 1 except that each material was blended according to the composition shown in Table 1.
  • Comparative Examples 1 to 6 A solder composition was obtained in the same manner as in Example 1 except that each material was blended according to the composition shown in Table 1.
  • solder composition (chip side ball, ball between pins, QFN void, power transistor component void, micro pad void) was performed by the following method. Table 1 shows the obtained results.
  • a substrate for evaluation was prepared by the following method. That is, a board (Tamura) on which chip components (1608 chips (size: 1.6 mm ⁇ 0.8 mm) and 1005 chips (size: 1.6 mm ⁇ 0.8 mm), QFP components, QFN chips, BGA components) can be mounted.
  • a solder composition was printed using a metal mask having a thickness of 120 ⁇ m, and 60 chip components were mounted under any of the following reflow conditions A and B.
  • the reflow conditions A and B are as follows.
  • the preheat temperature is 150 to 180 ° C. (about 80 seconds), the time at a temperature of 220 ° C. or more is about 50 seconds, and the peak temperature is 245 ° C.
  • Reflow condition B The preheat temperature is 150 to 180 ° C.
  • Chip Side Ball The evaluation substrate obtained under the reflow condition A was observed with a magnifying glass, and the number of solder balls (sides / chip) generated on the side of the chip component was measured. B: The number of solder balls per chip is less than three. D: The number of solder balls per chip is three or more.
  • Ball between pins Observation of the evaluation board obtained under the reflow condition A with a magnifying glass was performed, and the result of the number of solder balls (pins / pin) generated between the pins of the QFP component (0.8 mm pitch) was obtained. Based on the following criteria, the balls between pins were evaluated.
  • the number of solder balls per pin is less than 100.
  • D The number of solder balls per pin is 100 or more.
  • a power transistor (size: 5.5 mm x 6.5 mm, thickness: 2.3 mm, land: tin plating, land area: 30 mm2) is mounted on a substrate having electrodes.
  • the solder composition was printed using a metal mask having a pattern. Thereafter, a power transistor was mounted on the solder composition, and reflow was performed under reflow conditions A, thereby producing a test substrate.
  • the solder joints on the obtained test substrate were observed using an X-ray inspection apparatus (“NLX-5000”, manufactured by NAGOYA ELECTRIC WORKS).
  • the results of the solder compositions of the present invention were as follows: chip side balls, inter-pin balls, QFN voids, power transistor component voids, and micro pad voids. It was confirmed that it was good. Therefore, it was confirmed that voids can be sufficiently suppressed according to the solder composition of the present invention.
  • solder composition of the present invention can be suitably used as a technique for mounting an electronic component on an electronic substrate such as a printed wiring board of an electronic device.

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  • Electric Connection Of Electric Components To Printed Circuits (AREA)

Abstract

A solder composition according to the present invention is characterized by comprising: a flux composition containing (A) a rosin resin, (B) an activator, and (C) a solvent; and (D) a solder powder having a melting point of 200-250°C, wherein the (B) component contains at least one substance selected from the group consisting of (B1) aromatic carboxylic acids having a hydroxy group only at the ortho position or the pros position, (B2) dicarboxylic acids having an alkylene group and having 2-8 carbon atoms, and (B3) monocarboxylic acids having an alkyl group and having 2-8 carbon atoms, and the component (C) contains (C1) a diol or a diol diacetate having a boiling point of 220–250°C.

Description

はんだ組成物および電子基板Solder composition and electronic substrate
　本発明は、はんだ組成物および電子基板に関する。 The present invention relates to a solder composition and an electronic substrate.
　はんだ組成物は、はんだ粉末にフラックス組成物（ロジン系樹脂、活性剤および溶剤など）を混練してペースト状にした混合物である（例えば、特許文献１）。このはんだ組成物においては、はんだ溶融性やはんだが濡れ広がりやすいという性質（はんだ濡れ広がり）などのはんだ付け性とともに、ボイドの抑制や印刷性などが要求されている。
　一方で、電子機器の機能の多様化により、大型の電子部品が電子基板に搭載されるようになっている。また、大型の電子部品の中には、電極端子の面積が広い電子部品（例えば、ＱＦＮ（Ｑｕａｄ　Ｆｌａｔｐａｃｋ　Ｎｏ　Ｌｅａｄ）、パワートランジスタ）がある。このような電子部品では、はんだ組成物の印刷面積が広いため、ボイドが発生しやすい傾向にある。 The solder composition is a mixture obtained by kneading a flux composition (a rosin-based resin, an activator, a solvent, and the like) with a solder powder to form a paste (for example, Patent Document 1). In this solder composition, in addition to solderability such as solder melting property and a property that solder easily spreads (solder wet spreading), suppression of voids and printability are required.
On the other hand, with the diversification of functions of electronic devices, large-sized electronic components have been mounted on electronic substrates. Further, among large electronic components, there are electronic components having a large electrode terminal area (for example, QFN (Quad Flatpack No Lead), power transistor). In such an electronic component, the printed area of the solder composition is large, so that voids tend to be easily generated.
特許第５７５６０６７号Patent No. 5756067
　はんだ組成物において、ボイドを低減するために、イソボルニルシクロヘキサノールのような高沸点で高粘度の溶剤を用いることが検討されている。しかしながら、このように高沸点で高粘度の溶剤を用いても、ＱＦＮのような電極端子の面積が広い電子部品に対しては、ボイドを低減する効果が不十分であることが分かった。 In a solder composition, use of a solvent having a high boiling point and a high viscosity, such as isobornylcyclohexanol, has been studied in order to reduce voids. However, it has been found that even with such a high boiling point and high viscosity solvent, the effect of reducing voids is insufficient for electronic components such as QFN having a large electrode terminal area.
　そこで、本発明は、ボイドを十分に抑制できるはんだ組成物、およびそれを用いた電子基板を提供することを目的とする。 Accordingly, an object of the present invention is to provide a solder composition that can sufficiently suppress voids, and an electronic substrate using the same.
　前記課題を解決すべく、本発明は、以下のようなはんだ組成物および電子基板を提供するものである。
　本発明のはんだ組成物は、（Ａ）ロジン系樹脂、（Ｂ）活性剤および（Ｃ）溶剤を含有するフラックス組成物と、（Ｄ）融点が２００℃以上２５０℃以下であるはんだ粉末とを含有し、前記（Ｂ）成分が、（Ｂ１）オルト位またはプロス位のみに水酸基を有する芳香族カルボン酸、（Ｂ２）アルキレン基を有し、炭素数が２～８のジカルボン酸、および、（Ｂ３）アルキル基を有し、炭素数が２～８のモノカルボン酸からなる群から選択される少なくとも１種を含有し、前記（Ｃ）成分が、（Ｃ１）沸点が２２０℃以上２５０℃以下である、ジオール、または、ジオールのジアセテートを含有することを特徴とするものである。 In order to solve the above problems, the present invention provides the following solder composition and electronic substrate.
The solder composition of the present invention comprises: (A) a flux composition containing a rosin-based resin, (B) an activator, and (C) a solvent, and (D) a solder powder having a melting point of 200 ° C. or more and 250 ° C. or less. (B1) an aromatic carboxylic acid having a hydroxyl group only at the ortho or pros position, (B2) a dicarboxylic acid having an alkylene group and having 2 to 8 carbon atoms, and B3) An alkyl group, containing at least one member selected from the group consisting of monocarboxylic acids having 2 to 8 carbon atoms, wherein the component (C) is (C1) having a boiling point of 220 ° C or higher and 250 ° C or lower. Which is characterized by containing a diol or a diacetate of a diol.
　本発明のはんだ組成物においては、前記（Ｃ１）成分が、１，４－ブタンジオール、１，５－ペンタンジオール、２－エチル－１，３－ヘキサンジオール、１，２－ヘキサンジオール、ジプロピレングリコール、１，４－ブタンジオールジアセテート、および１，３－ブチレンジオールジアセテートからなる群から選択される少なくとも１種であることが好ましい。
　本発明のはんだ組成物においては、前記（Ｃ１）成分の沸点が、２３０℃以上２５０℃以下であることが好ましい。
　本発明のはんだ組成物においては、前記（Ｂ）成分が、（Ｂ４）ダイマー酸をさらに含有することが好ましい。
　本発明の電子基板は、前記はんだ組成物を用いたはんだ付け部を備えることを特徴とするものである。 In the solder composition of the present invention, the component (C1) comprises 1,4-butanediol, 1,5-pentanediol, 2-ethyl-1,3-hexanediol, 1,2-hexanediol, dipropylene It is preferably at least one selected from the group consisting of glycol, 1,4-butanediol diacetate, and 1,3-butylene diol diacetate.
In the solder composition of the present invention, the component (C1) preferably has a boiling point of 230 ° C. or more and 250 ° C. or less.
In the solder composition of the present invention, the component (B) preferably further contains (B4) dimer acid.
An electronic substrate according to the present invention includes a soldered portion using the solder composition.
　本発明のはんだ組成物によれば、ボイドを十分に抑制できる理由は必ずしも定かではないが、本発明者らは以下のように推察する。
　すなわち、本発明のはんだ組成物においては、（Ｃ）溶剤として、（Ｃ１）沸点が２２０℃以上２５０℃以下である、ジオール、または、ジオールのジアセテートを用いている。（Ｃ１）成分は、その一部は、はんだが溶融する前やはんだ溶融時に揮発して気体となってしまうが、この気体が、はんだ組成物中の気体を外部に押し出す作用がある。そして、揮発しなかった（Ｃ１）成分を含有するはんだ組成物は、はんだ溶融時にもある程度の流動性を有しているため、はんだ組成物中の気体が徐々に集まりながら外部に放出される。このようにして、ボイドを十分に抑制できる。また、有機酸の種類によっては、ボイドの発生要因となりえる。これに対し、本発明においては、ボイドの発生要因となりにくい有機酸（（Ｂ１）成分など）を選択して使用している。以上のようにして、上記本発明の効果が達成されるものと本発明者らは推察する。 According to the solder composition of the present invention, the reason why voids can be sufficiently suppressed is not always clear, but the present inventors speculate as follows.
That is, in the solder composition of the present invention, (C1) a diol or a diol diacetate having a boiling point of 220 ° C. or more and 250 ° C. or less is used as the solvent (C). Part of the component (C1) is volatilized before the solder is melted or when the solder is melted and becomes a gas. This gas has an effect of pushing out the gas in the solder composition to the outside. Since the solder composition containing the component (C1) that has not volatilized has a certain degree of fluidity even when the solder is melted, the gas in the solder composition is gradually collected and released to the outside. In this way, voids can be sufficiently suppressed. In addition, depending on the type of the organic acid, it can be a factor for generating voids. On the other hand, in the present invention, an organic acid (such as the component (B1)) which does not easily cause voids is selected and used. The present inventors presume that the effects of the present invention are achieved as described above.
　本発明によれば、ボイドを十分に抑制できるはんだ組成物、並びにそれを用いた電子基板を提供できる。 According to the present invention, a solder composition capable of sufficiently suppressing voids and an electronic substrate using the same can be provided.
　本発明のはんだ組成物は、以下説明するフラックス組成物と、以下説明する（Ｄ）はんだ粉末とを含有するものである。 は ん だ The solder composition of the present invention contains a flux composition described below and a solder powder (D) described below.
　［フラックス組成物］
　まず、本発明に用いるフラックス組成物について説明する。本発明に用いるフラックス組成物は、はんだ組成物におけるはんだ粉末以外の成分であり、（Ａ）ロジン系樹脂、（Ｂ）活性剤および（Ｃ）溶剤を含有するものである。 [Flux composition]
First, the flux composition used in the present invention will be described. The flux composition used in the present invention is a component other than the solder powder in the solder composition, and contains (A) a rosin-based resin, (B) an activator, and (C) a solvent.
　［（Ａ）成分］
　　本実施形態に用いる（Ａ）ロジン系樹脂としては、ロジン類およびロジン系変性樹脂が挙げられる。ロジン類としては、ガムロジン、ウッドロジンおよびトール油ロジンなどが挙げられる。ロジン系変性樹脂としては、不均化ロジン、重合ロジン、水素添加ロジンおよびこれらの誘導体などが挙げられる。水素添加ロジンとしては、完全水添ロジン、部分水添ロジン、並びに、不飽和有機酸（（メタ）アクリル酸などの脂肪族の不飽和一塩基酸、フマル酸、マレイン酸などのα，β－不飽和カルボン酸などの脂肪族不飽和二塩基酸、桂皮酸などの芳香族環を有する不飽和カルボン酸など）の変性ロジンである不飽和有機酸変性ロジンの水素添加物（「水添酸変性ロジン」ともいう）などが挙げられる。これらのロジン系樹脂は１種を単独で用いてもよく、２種以上を混合して用いてもよい。 [(A) component]
The rosin-based resin (A) used in the present embodiment includes rosins and rosin-modified resins. Rosins include gum rosin, wood rosin and tall oil rosin. Examples of the rosin-based modified resin include disproportionated rosin, polymerized rosin, hydrogenated rosin, and derivatives thereof. Examples of the hydrogenated rosin include fully hydrogenated rosin, partially hydrogenated rosin, and unsaturated organic acids (such as aliphatic unsaturated monobasic acids such as (meth) acrylic acid), α, β- such as fumaric acid and maleic acid. A hydrogenated product of an unsaturated organic acid-modified rosin that is a modified rosin of an aliphatic unsaturated dibasic acid such as an unsaturated carboxylic acid, an unsaturated carboxylic acid having an aromatic ring such as cinnamic acid, etc. Rosin). These rosin-based resins may be used alone or in a combination of two or more.
（Ａ）成分の配合量は、フラックス組成物１００質量％に対して、２０質量％以上７０質量％以下であることが好ましく、３０質量％以上６０質量％以下であることがより好ましい。（Ａ）成分の配合量が前記下限以上であれば、はんだ付ランドの銅箔面の酸化を防止してその表面に溶融はんだを濡れやすくする、いわゆるはんだ付け性を向上でき、はんだボールを十分に抑制できる。また、（Ａ）成分の配合量が前記上限以下であれば、フラックス残さ量を十分に抑制できる。 The amount of the component (A) is preferably from 20% by mass to 70% by mass, more preferably from 30% by mass to 60% by mass, based on 100% by mass of the flux composition. When the amount of the component (A) is not less than the lower limit, it is possible to prevent the oxidation of the copper foil surface of the soldering land and to easily wet the molten solder on the surface. Can be suppressed. In addition, when the amount of the component (A) is equal to or less than the upper limit, the amount of flux residue can be sufficiently suppressed.
　［（Ｂ）成分］
　本実施形態に用いる（Ｂ）活性剤は、（Ｂ１）オルト位またはプロス位のみに水酸基を有する芳香族カルボン酸、（Ｂ２）アルキレン基を有し、炭素数が２～８のジカルボン酸、および、（Ｂ３）アルキル基を有し、炭素数が２～８のモノカルボン酸からなる群から選択される少なくとも１種を含有する。これら（Ｂ１）成分～（Ｂ３）成分は、ボイドの発生要因になりにくい。 [Component (B)]
The activator (B) used in this embodiment includes (B1) an aromatic carboxylic acid having a hydroxyl group only at the ortho or pros position, (B2) a dicarboxylic acid having an alkylene group and having 2 to 8 carbon atoms, and , (B3) having an alkyl group and containing at least one member selected from the group consisting of monocarboxylic acids having 2 to 8 carbon atoms. These components (B1) to (B3) hardly cause voids.
　（Ｂ１）成分としては、２，６－ジヒドロキシ安息香酸、２－ヒドロキシ安息香酸、１－ヒドロキシ－２－ナフトエ酸、および３－ヒドロキシ－２－ナフトエ酸などが挙げられる。これらの中でも、２，６－ジヒドロキシ安息香酸が特に好ましい。これらは１種を単独で用いてもよく、２種以上を混合して用いてもよい。
　（Ｂ２）成分としては、シュウ酸、マロン酸、コハク酸、グルタル酸、アジピン酸、ピメリン酸、およびスベリン酸が挙げられる。これらの中でも、コハク酸、グルタル酸、アジピン酸が好ましく、コハク酸、アジピン酸がより好ましい。これらは１種を単独で用いてもよく、２種以上を混合して用いてもよい。
　（Ｂ３）成分としては、酢酸、プロピオン酸、ブチリック酸、バレリック酸、カプロン酸、エナント酸、およびカプリル酸などが挙げられる。これらは１種を単独で用いてもよく、２種以上を混合して用いてもよい。
　これら（Ｂ１）成分～（Ｂ３）成分の中でも、ボイドおよび活性作用の観点から、（Ｂ１）成分および（Ｂ２）成分がより好ましく、（Ｂ１）成分が特に好ましい。
　（Ｂ１）成分～（Ｂ３）成分の合計配合量は、ボイドおよび活性作用の観点から、フラックス組成物１００質量％に対して、１質量％以上７質量％以下であることが好ましく、１．５質量％以上５質量％以下であることがより好ましく、２質量％以上３質量％以下であることが特に好ましい。 Examples of the component (B1) include 2,6-dihydroxybenzoic acid, 2-hydroxybenzoic acid, 1-hydroxy-2-naphthoic acid, and 3-hydroxy-2-naphthoic acid. Among these, 2,6-dihydroxybenzoic acid is particularly preferred. These may be used alone or as a mixture of two or more.
Examples of the component (B2) include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, and suberic acid. Among these, succinic acid, glutaric acid and adipic acid are preferred, and succinic acid and adipic acid are more preferred. These may be used alone or as a mixture of two or more.
Examples of the component (B3) include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, and caprylic acid. These may be used alone or as a mixture of two or more.
Among the components (B1) to (B3), the components (B1) and (B2) are more preferable, and the component (B1) is particularly preferable, from the viewpoint of voids and active action.
The total blending amount of the components (B1) to (B3) is preferably 1% by mass or more and 7% by mass or less with respect to 100% by mass of the flux composition, from the viewpoint of voids and active action. It is more preferably from 5% by mass to 5% by mass, particularly preferably from 2% by mass to 3% by mass.
　本実施形態において、（Ｂ）成分は、（Ｂ４）ダイマー酸をさらに含有してもよい。この（Ｂ４）成分により、はんだ粉末の再酸化を防止できる傾向があるために、他の活性剤の作用を相乗的に高めることができる。また、（Ｂ４）成分は、ボイドの発生要因になりにくい。
　（Ｂ４）成分は、不飽和脂肪酸の重合によって生成されるダイマー酸であることが好ましい。この不飽和脂肪酸の炭素数は、特に限定されないが、８以上２２以下であることが好ましく、１２以上１８以下であることがより好ましく、１８であることが特に好ましい。また、ダイマー酸は、二塩基酸を主成分（５０質量％以上）とするものであればよく、一塩基酸または三塩基酸を含有していてもよい。
　本実施形態においては、チップ脇ボールおよびボイドの抑制の観点から、（Ｂ１）成分～（Ｂ４）成分以外の有機酸を用いないことが好ましい。
　（Ｂ４）成分の配合量は、ボイドおよび活性作用の観点から、フラックス組成物１００質量％に対して、１質量％以上２０質量％以下であることが好ましく、３質量％以上１５質量％以下であることがより好ましく、５質量％以上１０質量％以下であることが特に好ましい。 In this embodiment, the component (B) may further contain (B4) dimer acid. Since the component (B4) tends to prevent reoxidation of the solder powder, the action of another activator can be synergistically enhanced. The component (B4) hardly causes voids.
The component (B4) is preferably a dimer acid produced by polymerization of an unsaturated fatty acid. The carbon number of the unsaturated fatty acid is not particularly limited, but is preferably 8 or more and 22 or less, more preferably 12 or more and 18 or less, and particularly preferably 18. Further, the dimer acid may be one having a dibasic acid as a main component (50% by mass or more), and may contain a monobasic acid or a tribasic acid.
In the present embodiment, it is preferable not to use an organic acid other than the components (B1) to (B4) from the viewpoint of suppressing chip side balls and voids.
The blending amount of the component (B4) is preferably from 1% by mass to 20% by mass, and more preferably from 3% by mass to 15% by mass, based on 100% by mass of the flux composition, from the viewpoint of voids and activating action. It is more preferable that the content is 5% by mass or more and 10% by mass or less.
　（Ｂ）成分は、本発明の課題を達成できる範囲において、（Ｂ１）成分～（Ｂ４）成分以外に、その他の活性剤（（Ｂ５）ハロゲン系活性剤、および（Ｂ６）アミン系活性剤など）をさらに含有してもよい。なお、（Ｂ１）成分～（Ｂ４）成分の合計配合量は、ボイドおよび活性作用の観点から、（Ｂ）成分１００質量％に対して、９０質量％以上であることが好ましく、９５質量％以上であることがより好ましい。 The component (B) includes, in addition to the components (B1) to (B4), other activators ((B5) a halogen-based activator and (B6) an amine-based activator) as long as the object of the present invention can be achieved. ) May be further contained. The total amount of the components (B1) to (B4) is preferably 90% by mass or more, and more preferably 95% by mass or more based on 100% by mass of the component (B) from the viewpoint of voids and active action. Is more preferable.
　（Ｂ５）成分としては、塩素化物、臭素化物、フッ化物のように塩素、臭素、フッ素の各単独元素の共有結合による化合物でもよいが、塩素、臭素およびフッ素の任意の２つまたは全部のそれぞれの共有結合を有する化合物でもよい。これらの化合物は、水性溶媒に対する溶解性を向上させるために、例えばハロゲン化アルコールやハロゲン化カルボキシル化合物のように水酸基やカルボキシル基などの極性基を有することが好ましい。ハロゲン化アルコールとしては、例えば、臭素化アルコール（２，３－ジブロモプロパノール、２，３－ジブロモブタンジオール、トランス－２，３－ジブロモ－２－ブテン－１，４－ジオール、１，４－ジブロモ－２－ブタノール、およびトリブロモネオペンチルアルコールなど）、塩素化アルコール（１，３－ジクロロ－２－プロパノール、および１，４－ジクロロ－２－ブタノールなど）、フッ素化アルコール（３－フルオロカテコールなど）、並びに、その他これらに類する化合物が挙げられる。ハロゲン化カルボキシル化合物としては、ヨウ化カルボキシル化合物（２－ヨード安息香酸、３－ヨード安息香酸、２－ヨードプロピオン酸、５－ヨードサリチル酸、および５－ヨードアントラニル酸など）、塩化カルボキシル化合物（２－クロロ安息香酸、および３－クロロプロピオン酸など）、臭素化カルボキシル化合物（２，３－ジブロモプロピオン酸、２，３－ジブロモコハク酸、および２－ブロモ安息香酸など）、並びに、その他これらに類する化合物が挙げられる。なお、これらは１種を単独で用いてもよく、２種以上を混合して用いてもよい。 The component (B5) may be a compound formed by a covalent bond of each of chlorine, bromine, and fluorine, such as chlorinated, brominated, and fluoride, or any two or all of chlorine, bromine, and fluorine. May be a compound having a covalent bond of These compounds preferably have a polar group such as a hydroxyl group or a carboxyl group like a halogenated alcohol or a halogenated carboxyl compound in order to improve solubility in an aqueous solvent. Examples of the halogenated alcohol include brominated alcohols (2,3-dibromopropanol, 2,3-dibromobutanediol, trans-2,3-dibromo-2-butene-1,4-diol, 1,4-dibromo -2-butanol, tribromoneopentyl alcohol, etc.), chlorinated alcohols (1,3-dichloro-2-propanol, 1,4-dichloro-2-butanol, etc.), fluorinated alcohols (3-fluorocatechol, etc.) ), And other similar compounds. Examples of the halogenated carboxyl compound include iodide carboxyl compounds (such as 2-iodobenzoic acid, 3-iodobenzoic acid, 2-iodopropionic acid, 5-iodosalicylic acid, and 5-iodoanthranilic acid), and carboxyl chloride compounds (2- Chlorobenzoic acid, 3-chloropropionic acid, etc.), brominated carboxyl compounds (2,3-dibromopropionic acid, 2,3-dibromosuccinic acid, 2-bromobenzoic acid, etc.), and other similar compounds Is mentioned. In addition, these may be used individually by 1 type, and may be used in mixture of 2 or more types.
　（Ｂ６）成分としては、アミン類（エチレンジアミンなどのポリアミンなど）、アミン塩類（トリメチロールアミン、シクロヘキシルアミン、およびジエチルアミンなどのアミンやアミノアルコールなどの有機酸塩や無機酸塩（塩酸、硫酸、および臭化水素酸など））、アミノ酸類（グリシン、アラニン、アスパラギン酸、グルタミン酸、およびバリンなど）、アミド系化合物、およびイミダゾール系化合物などが挙げられる。具体的には、ジフェニルグアニジン臭化水素酸塩、シクロヘキシルアミン臭化水素酸塩、ジエチルアミン塩（塩酸塩、コハク酸塩、アジピン酸塩、およびセバシン酸塩など）、トリエタノールアミン、モノエタノールアミン、並びに、これらのアミンの臭化水素酸塩などが挙げられる。 As the component (B6), amines (eg, polyamines such as ethylenediamine), amine salts (eg, amines such as trimethylolamine, cyclohexylamine, and diethylamine, and organic acid salts and inorganic acid salts such as aminoalcohols (hydrochloric acid, sulfuric acid, and the like) Hydrobromic acid), amino acids (such as glycine, alanine, aspartic acid, glutamic acid, and valine), amide compounds, and imidazole compounds. Specifically, diphenylguanidine hydrobromide, cyclohexylamine hydrobromide, diethylamine salt (such as hydrochloride, succinate, adipate, and sebacate), triethanolamine, monoethanolamine, And hydrobromides of these amines.
　（Ｂ）成分の配合量としては、フラックス組成物１００質量％に対して、１質量％以上２５質量％以下であることが好ましく、２質量％以上２０質量％以下であることがより好ましく、３質量％以上１５質量％以下であることが特に好ましい。（Ｂ）成分の配合量が前記下限未満では、はんだボールが生じやすくなる傾向にあり、他方、前記上限を超えると、フラックス組成物の絶縁性が低下する傾向にある。 The blending amount of the component (B) is preferably from 1% by mass to 25% by mass, more preferably from 2% by mass to 20% by mass, based on 100% by mass of the flux composition. It is particularly preferable that the content be from 15% by mass to 15% by mass. When the amount of the component (B) is less than the lower limit, solder balls tend to be easily formed. On the other hand, when the amount exceeds the upper limit, the insulating property of the flux composition tends to decrease.
　［（Ｃ）成分］
　本実施形態に用いる（Ｃ）溶剤は、（Ｃ１）沸点が２２０℃以上２５０℃以下である、ジオール、または、ジオールのジアセテートを含有することが必要である。（Ｃ１）成分により、ボイドの発生を抑制できる。
　なお、（Ｃ１）成分の沸点が２２０℃未満である場合、および、（Ｃ１）成分の沸点が２５０℃超である場合には、ボイドの発生を十分に抑制できない。なお、本明細書において、沸点とは、１０１３ｈＰａにおける沸点のことをいう。また、ボイドの観点から、（Ｃ１）成分の沸点は、２２０℃以上２４０℃以下であることが好ましく、２２５℃以上２３５℃以下であることがさらに好ましく、２３０℃以上２３５℃以下であることが特に好ましい。 [(C) component]
The (C) solvent used in the present embodiment needs to contain (C1) a diol or a diol diacetate having a boiling point of 220 ° C. or more and 250 ° C. or less. The generation of voids can be suppressed by the component (C1).
When the boiling point of the component (C1) is lower than 220 ° C. and when the boiling point of the component (C1) is higher than 250 ° C., the generation of voids cannot be sufficiently suppressed. In addition, in this specification, a boiling point means the boiling point in 1013 hPa. Further, from the viewpoint of voids, the boiling point of the component (C1) is preferably from 220 ° C to 240 ° C, more preferably from 225 ° C to 235 ° C, and more preferably from 230 ° C to 235 ° C. Particularly preferred.
　（Ｃ１）成分としては、１，４－ブタンジオール（沸点：２３０℃）、１，５－ペンタンジオール（沸点：２４０℃）、２－エチル－１，３－ヘキサンジオール（沸点：２４２℃）、１，２－ヘキサンジオール（沸点：２２３℃）、ジプロピレングリコール（沸点：２３０℃）、１，４－ブタンジオールジアセテート（沸点：２３２℃）、および１，３－ブチレンジオールジアセテート（沸点：２３２℃）などが挙げられる。これらの中でも、溶剤の融点の観点から、１，４－ブタンジオール、１，３－ブチレンジオールジアセテートがより好ましい。これらは１種を単独で用いてもよく、２種以上を混合して用いてもよい。 As the component (C1), 1,4-butanediol (boiling point: 230 ° C.), 1,5-pentanediol (boiling point: 240 ° C.), 2-ethyl-1,3-hexanediol (boiling point: 242 ° C.), 1,2-hexanediol (boiling point: 223 ° C.), dipropylene glycol (boiling point: 230 ° C.), 1,4-butanediol diacetate (boiling point: 232 ° C.), and 1,3-butylenediol diacetate (boiling point: 232 ° C.). Among these, 1,4-butanediol and 1,3-butylenediol diacetate are more preferred from the viewpoint of the melting point of the solvent. These may be used alone or as a mixture of two or more.
　（Ｃ）成分は、本発明の目的を達成できる範囲内において、（Ｃ１）成分以外の溶剤（（Ｃ２）成分）を含有していてもよい。
　（Ｃ２）成分としては、ジエチレングリコールモノヘキシルエーテル、ジエチレングリコールモノブチルエーテル、α,β,γ－ターピネオール、ベンジルグリコール、ジエチレングリコールモノ２－エチルヘキシルエーテル、トリプロピレングリコール、ジエチレングリコールモノベンジルエーテル、ジエチレングリコールジブチルエーテル、トリプロピレングリコールモノメチルエーテル、ジプロピレングリコールモノブチルエーテル、エチレングリコールモノ２－エチルヘキシルエーテル、ジエチレングリコールモノエチルエーテルアセテートおよび２，２－ジメチル－１，３－プロパンジオールなどが挙げられる。これらは１種を単独で用いてもよく、２種以上を混合して用いてもよい。 Component (C) may contain a solvent (component (C2)) other than component (C1) as long as the object of the present invention can be achieved.
As the component (C2), diethylene glycol monohexyl ether, diethylene glycol monobutyl ether, α, β, γ-terpineol, benzyl glycol, diethylene glycol mono-2-ethylhexyl ether, tripropylene glycol, diethylene glycol monobenzyl ether, diethylene glycol dibutyl ether, tripropylene glycol Monomethyl ether, dipropylene glycol monobutyl ether, ethylene glycol mono-2-ethylhexyl ether, diethylene glycol monoethyl ether acetate, 2,2-dimethyl-1,3-propanediol and the like can be mentioned. These may be used alone or as a mixture of two or more.
　（Ｃ２）成分を用いる場合、（Ｃ２）成分の（Ｃ）成分に対する質量比（（Ｃ２）／（Ｃ））は、ボイドの抑制と印刷性とのバランスの観点から、１／１５以上１／１以下であることが好ましく、１／１０以上１／２以下であることがより好ましく、１／５以上１／３以下であることが特に好ましい。 When the component (C2) is used, the mass ratio ((C2) / (C)) of the component (C2) to the component (C) is from 1/15 to 1/1, from the viewpoint of the balance between the suppression of voids and the printability. It is preferably 1 or less, more preferably 1/10 or more and 以下 or less, particularly preferably 1/5 or more and 1/3 or less.
　（Ｃ）成分の配合量は、フラックス組成物１００質量％に対して、２０質量％以上６０質量％以下であることが好ましく、２５質量％以上５０質量％以下であることがより好ましく、３０質量％以上４０質量％以下であることが特に好ましい。溶剤の配合量が前記範囲内であれば、得られるはんだ組成物の粘度を適正な範囲に適宜調整できる。 The compounding amount of the component (C) is preferably 20% by mass or more and 60% by mass or less, more preferably 25% by mass or more and 50% by mass or less, and more preferably 30% by mass or less with respect to 100% by mass of the flux composition. % To 40% by mass or less is particularly preferred. If the amount of the solvent is within the above range, the viscosity of the obtained solder composition can be appropriately adjusted to an appropriate range.
　本実施形態においては、印刷性などの観点から、さらにチクソ剤を含有していてもよい。本実施形態に用いるチクソ剤としては、硬化ひまし油、アミド類、カオリン、コロイダルシリカ、有機ベントナイト、およびガラスフリットなどが挙げられる。これらのチクソ剤は１種を単独で用いてもよく、２種以上を混合して用いてもよい。 に お い て In the present embodiment, a thixotropic agent may be further contained from the viewpoint of printability and the like. Examples of the thixotropic agent used in the present embodiment include hardened castor oil, amides, kaolin, colloidal silica, organic bentonite, and glass frit. One of these thixotropic agents may be used alone, or two or more thereof may be used in combination.
　チクソ剤を用いる場合、その配合量は、フラックス組成物１００質量％に対して、２質量％以上２０質量％以下であることが好ましく、４質量％以上１２質量％以下であることがより好ましい。配合量が前記下限未満では、チクソ性が得られず、ダレが生じやすくなる傾向にあり、他方、前記上限を超えると、チクソ性が高すぎて、印刷不良となりやすい傾向にある。 When a thixotropic agent is used, the amount thereof is preferably 2% by mass or more and 20% by mass or less, more preferably 4% by mass or more and 12% by mass or less based on 100% by mass of the flux composition. When the amount is less than the lower limit, thixotropic properties are not obtained and sagging tends to occur. On the other hand, when the amount exceeds the upper limit, the thixotropic properties are too high and printing tends to be poor.
　［他の成分］
　本実施形態に用いるフラックス組成物には、（Ａ）成分、（Ｂ）成分、（Ｃ）成分およびチクソ剤の他に、必要に応じて、その他の添加剤、更には、その他の樹脂を加えることができる。その他の添加剤としては、消泡剤、酸化防止剤、改質剤、つや消し剤、および発泡剤などが挙げられる。これらの添加剤の配合量としては、フラックス組成物１００質量％に対して、０．０１質量％以上５質量％以下であることが好ましい。その他の樹脂としては、アクリル系樹脂などが挙げられる。 [Other components]
To the flux composition used in the present embodiment, in addition to the component (A), the component (B), the component (C), and the thixo agent, other additives and further other resins are added as necessary. be able to. Other additives include defoamers, antioxidants, modifiers, matting agents, foaming agents, and the like. The amount of these additives is preferably 0.01% by mass or more and 5% by mass or less based on 100% by mass of the flux composition. Other resins include acrylic resins.
　［はんだ組成物］
　次に、本実施形態のはんだ組成物について説明する。本実施形態のはんだ組成物は、前述の本実施形態のフラックス組成物と、以下説明する（Ｄ）はんだ粉末とを含有するものである。
　フラックス組成物の配合量は、はんだ組成物１００質量％に対して、５質量％以上３５質量％以下であることが好ましく、７質量％以上１５質量％以下であることがより好ましく、８質量％以上１２質量％以下であることが特に好ましい。フラックス組成物の配合量が５質量％未満の場合（はんだ粉末の配合量が９５質量％を超える場合）には、バインダーとしてのフラックス組成物が足りないため、フラックス組成物とはんだ粉末とを混合しにくくなる傾向にあり、他方、フラックス組成物の配合量が３５質量％を超える場合（はんだ粉末の配合量が６５質量％未満の場合）には、得られるはんだ組成物を用いた場合に、十分なはんだ接合を形成できにくくなる傾向にある。 [Solder composition]
Next, the solder composition of the present embodiment will be described. The solder composition of the present embodiment contains the above-described flux composition of the present embodiment and (D) a solder powder described below.
The compounding amount of the flux composition is preferably from 5% by mass to 35% by mass, more preferably from 7% by mass to 15% by mass, and more preferably 8% by mass, based on 100% by mass of the solder composition. It is particularly preferable that the content be at least 12 mass%. When the compounding amount of the flux composition is less than 5% by mass (when the compounding amount of the solder powder exceeds 95% by mass), the flux composition as a binder is insufficient, so that the flux composition and the solder powder are mixed. On the other hand, when the amount of the flux composition exceeds 35% by mass (when the amount of the solder powder is less than 65% by mass), when the obtained solder composition is used, It tends to be difficult to form a sufficient solder joint.
　［（Ｄ）成分］
　本実施形態に用いる（Ｄ）はんだ粉末は、融点が２００℃以上２５０℃以下であるはんだ粉末である。本実施形態においては、融点が２００℃以上２５０℃以下のはんだ粉末を使用する前提で、（Ｃ１）成分の沸点を規定している。
　このはんだ粉末におけるはんだ合金としては、スズ（Ｓｎ）を主成分とする合金が好ましい。また、この合金の第二元素としては、銀（Ａｇ）、銅（Ｃｕ）、亜鉛（Ｚｎ）、ビスマス（Ｂｉ）、インジウム（Ｉｎ）およびアンチモン（Ｓｂ）などが挙げられる。さらに、この合金には、必要に応じて他の元素（第三元素以降）を添加してもよい。他の元素としては、銅、銀、ビスマス、インジウム、アンチモン、およびアルミニウム（Ａｌ）などが挙げられる。
　ここで、鉛フリーはんだ粉末とは、鉛を添加しないはんだ金属または合金の粉末のことをいう。ただし、鉛フリーはんだ粉末中に、不可避的不純物として鉛が存在することは許容されるが、この場合に、鉛の量は、３００質量ｐｐｍ以下であることが好ましい。 [(D) component]
The solder powder (D) used in the present embodiment is a solder powder having a melting point of 200 ° C. or more and 250 ° C. or less. In the present embodiment, the boiling point of the component (C1) is defined on the assumption that a solder powder having a melting point of 200 ° C. or more and 250 ° C. or less is used.
As a solder alloy in the solder powder, an alloy containing tin (Sn) as a main component is preferable. The second element of the alloy includes silver (Ag), copper (Cu), zinc (Zn), bismuth (Bi), indium (In), and antimony (Sb). Further, other elements (third and subsequent elements) may be added to this alloy as needed. Other elements include copper, silver, bismuth, indium, antimony, aluminum (Al), and the like.
Here, the lead-free solder powder refers to a solder metal or alloy powder to which lead is not added. However, the presence of lead as an unavoidable impurity in the lead-free solder powder is acceptable, but in this case, the amount of lead is preferably 300 ppm by mass or less.
　鉛フリーはんだ粉末におけるはんだ合金としては、具体的には、Ｓｎ－Ａｇ系、およびＳｎ－Ａｇ－Ｃｕ系などが挙げられる。これらの中でも、はんだ接合の強度の観点から、Ｓｎ－Ａｇ－Ｃｕ系のはんだ合金が好ましく用いられている。そして、Ｓｎ－Ａｇ－Ｃｕ系のはんだの融点は、通常２００℃以上２５０℃以下（好ましくは、２００℃以上２４０℃以下）である。なお、Ｓｎ－Ａｇ－Ｃｕ系のはんだの中でも、銀含有量が低い系統のはんだの融点は、２１０℃以上２５０℃以下（好ましくは、２２０℃以上２４０℃以下）である。 は ん だ Specific examples of the solder alloy in the lead-free solder powder include Sn-Ag and Sn-Ag-Cu. Among these, Sn-Ag-Cu-based solder alloys are preferably used from the viewpoint of the strength of the solder joint. The melting point of the Sn—Ag—Cu solder is usually 200 ° C. to 250 ° C. (preferably, 200 ° C. to 240 ° C.). In addition, among Sn-Ag-Cu solders, the solder having a low silver content has a melting point of 210 ° C. or more and 250 ° C. or less (preferably 220 ° C. or more and 240 ° C. or less).
　（Ｄ）成分の平均粒子径は、通常１μｍ以上４０μｍ以下であるが、はんだ付けパッドのピッチが狭い電子基板にも対応するという観点から、１μｍ以上３５μｍ以下であることがより好ましく、２μｍ以上３０μｍ以下であることがさらにより好ましく、３μｍ以上２０μｍ以下であることが特に好ましい。なお、平均粒子径は、動的光散乱式の粒子径測定装置により測定できる。 The average particle diameter of the component (D) is usually 1 μm or more and 40 μm or less, but is preferably 1 μm or more and 35 μm or less, more preferably 2 μm or more and 30 μm or less, from the viewpoint of supporting an electronic substrate having a narrow solder pad pitch. It is still more preferable that the thickness is not more than 3 μm and particularly preferably not more than 3 μm and not more than 20 μm. The average particle size can be measured by a dynamic light scattering type particle size measuring device.
　［はんだ組成物の製造方法］
　本実施形態のはんだ組成物は、上記説明したフラックス組成物と上記説明した（Ｄ）はんだ粉末とを上記所定の割合で配合し、撹拌混合することで製造できる。 [Solder composition manufacturing method]
The solder composition of the present embodiment can be manufactured by blending the above-described flux composition and the above-described (D) solder powder at the above-described predetermined ratio and stirring and mixing.
　［電子基板］
　次に、本実施形態の電子基板について説明する。本実施形態の電子基板は、以上説明したはんだ組成物を用いたはんだ付け部を備えることを特徴とするものである。本発明の電子基板は、前記はんだ組成物を用いて電子部品を電子基板（プリント配線基板など）に実装することで製造できる。
　前述した本実施形態のはんだ組成物は、はんだ組成物の印刷面積が広い場合でも、大きな径のボイドを十分に抑制できる。そのため、電子部品としては、電極端子の面積が広い電子部品（例えば、ＱＦＮ、パワートランジスタ）を用いてもよい。また、はんだ組成物の印刷面積は、例えば、２０ｍｍ２以上であってもよく、３０ｍｍ２以上であってもよく、４０ｍｍ２以上であってもよい。なお、印刷面積は、電子部品の電極端子の面積に対応する。
　ここで用いる塗布装置としては、スクリーン印刷機、メタルマスク印刷機、ディスペンサー、およびジェットディスペンサーなどが挙げられる。
　また、前記塗布装置にて塗布したはんだ組成物上に電子部品を配置し、リフロー炉により所定条件にて加熱して、前記電子部品をプリント配線基板に実装するリフロー工程により、電子部品を電子基板に実装できる。 [Electronic substrate]
Next, the electronic substrate of the present embodiment will be described. The electronic substrate according to the present embodiment includes a soldered portion using the above-described solder composition. The electronic substrate of the present invention can be manufactured by mounting an electronic component on an electronic substrate (such as a printed wiring board) using the solder composition.
The above-described solder composition of the present embodiment can sufficiently suppress large-diameter voids even when the printed area of the solder composition is large. Therefore, an electronic component having a large electrode terminal area (for example, QFN, power transistor) may be used as the electronic component. The printed area of the solder composition may be, for example, 20 mm 2 or more, 30 mm 2 or more, or 40 mm 2 or more. Note that the printing area corresponds to the area of the electrode terminal of the electronic component.
Examples of the coating device used here include a screen printing machine, a metal mask printing machine, a dispenser, and a jet dispenser.
Further, the electronic component is placed on the solder composition applied by the coating device, heated by a reflow oven under predetermined conditions, and the electronic component is mounted on a printed wiring board by a reflow process. Can be implemented.
　リフロー工程においては、前記はんだ組成物上に前記電子部品を配置し、リフロー炉により所定条件にて加熱する。このリフロー工程により、電子部品およびプリント配線基板の間に十分なはんだ接合を行うことができる。その結果、前記電子部品を前記プリント配線基板に実装することができる。
　リフロー条件は、はんだの融点に応じて適宜設定すればよい。例えば、プリヒート温度は、１４０℃以上２００℃以下であることが好ましく、１５０℃以上１６０℃以下であることがより好ましい。プリヒート時間は、６０秒間以上１２０秒間以下であることが好ましい。ピーク温度は、２３０℃以上２７０℃以下であることが好ましく、２４０℃以上２５５℃以下であることがより好ましい。また、２２０℃以上の温度の保持時間は、２０秒間以上６０秒間以下であることが好ましい。 In the reflow step, the electronic component is placed on the solder composition, and heated by a reflow furnace under predetermined conditions. By this reflow step, a sufficient solder joint can be performed between the electronic component and the printed wiring board. As a result, the electronic component can be mounted on the printed wiring board.
The reflow condition may be appropriately set according to the melting point of the solder. For example, the preheat temperature is preferably from 140 ° C to 200 ° C, more preferably from 150 ° C to 160 ° C. The preheating time is preferably from 60 seconds to 120 seconds. The peak temperature is preferably from 230 ° C to 270 ° C, more preferably from 240 ° C to 255 ° C. The holding time at a temperature of 220 ° C. or more is preferably 20 seconds or more and 60 seconds or less.
　また、本実施形態のはんだ組成物および電子基板は、前記実施形態に限定されるものではなく、本発明の目的を達成できる範囲での変形、改良などは本発明に含まれるものである。
　例えば、前記電子基板では、リフロー工程により、プリント配線基板と電子部品とを接着しているが、これに限定されない。例えば、リフロー工程に代えて、レーザー光を用いてはんだ組成物を加熱する工程（レーザー加熱工程）により、プリント配線基板と電子部品とを接着してもよい。この場合、レーザー光源としては、特に限定されず、金属の吸収帯に合わせた波長に応じて適宜採用できる。レーザー光源としては、例えば、固体レーザー（ルビー、ガラス、ＹＡＧなど）、半導体レーザー（ＧａＡｓ、およびＩｎＧａＡｓＰなど）、液体レーザー（色素など）、並びに、気体レーザー（Ｈｅ－Ｎｅ、Ａｒ、ＣＯ２、およびエキシマーなど）が挙げられる。 Further, the solder composition and the electronic substrate of the present embodiment are not limited to the above embodiment, and modifications and improvements as long as the object of the present invention can be achieved are included in the present invention.
For example, in the electronic board, the printed wiring board and the electronic component are bonded by the reflow process, but the present invention is not limited to this. For example, instead of the reflow step, the printed wiring board and the electronic component may be bonded to each other by a step of heating the solder composition using a laser beam (laser heating step). In this case, the laser light source is not particularly limited, and can be appropriately adopted according to the wavelength adjusted to the absorption band of the metal. As a laser light source, for example, a solid laser (ruby, glass, YAG, etc.), a semiconductor laser (GaAs, InGaAsP, etc.), a liquid laser (dye, etc.), and a gas laser (He—Ne, Ar, CO 2 , Excimer, etc.).
　次に、本発明を実施例および比較例によりさらに詳細に説明するが、本発明はこれらの例によってなんら限定されるものではない。なお、実施例および比較例にて用いた材料を以下に示す。
（（Ａ）成分）
ロジン系樹脂：水添酸変性ロジン、商品名「パインクリスタルＫＥ－６０４」、荒川化学工業社製
（（Ｂ１）成分）
有機酸Ａ：２，６－ジヒドロキシ安息香酸、東京化成社製
（（Ｂ２）成分）
有機酸Ｂ：コハク酸、東京化成社製
有機酸Ｃ：アジピン酸、東京化成社製
有機酸Ｄ：グルタル酸、東京化成社製
有機酸Ｅ：ピメリン酸、東京化成社製
有機酸Ｆ：スベリン酸、東京化成社製
（（Ｂ４）成分）
有機酸Ｇ：ダイマー酸、商品名「ＵＮＩＤＹＭＥ１４」、エア・ブラウン社製
（（Ｂ５）成分）
ハロゲン系活性剤：トランス－２，３－ジブロモ－２－ブテン－１，４－ジオール（ＴＤＢＤ）
（（Ｃ１）成分）
溶剤Ａ：１，４－ブタンジオール（沸点：２３０℃）、東京化成社製
溶剤Ｂ：１，３－ブチレンジオールジアセテート（沸点：２３２℃）、ダイセル化学社製
溶剤Ｃ：１，５－ペンタンジオール（沸点：２４０℃）、東京化成社製
溶剤Ｄ：２－エチル－１，３－ヘキサンジオール（沸点：２４２℃）、日本乳化剤社製
溶剤Ｅ：１，４－ブタンジオールジアセテート（沸点：２３２℃）、商品名「ＣＥＬＴＯＬ　１，４－ＢＤＤＡ」、ダイセル化学社製
溶剤Ｆ：ジプロピレングリコール（沸点：２３０℃）、東京化成社製
溶剤Ｇ：１，２－ヘキサンジオール（沸点：２２３℃）、大阪有機化学工業社製
（（Ｃ２）成分）
溶剤Ｈ：２，４－ジエチル－１，５－ペンタンジオール（沸点：３００℃）、商品名「キョーワジオールＰＤ－９」、ＫＨネオケム社製
溶剤Ｉ：１－（２－ブトキシ－１－メチルエトキシ）プロパン－２－オール（沸点：２３０℃）、ダウ・ケミカル社製
溶剤Ｊ：ジエチレングリコールモノエチルエーテルアセテート（沸点：２１７℃）
溶剤Ｋ：ジプロピレングリコールモノプロピルエーテル（沸点：２１２℃）
（（Ｄ）成分）
はんだ粉末：合金組成はＳｎ－３．０Ａｇ－０．５Ｃｕ、粒子径分布は２０～３８μｍ、はんだ融点は２１７～２２０℃
（他の成分）
有機酸Ｈ：２，４－ジヒドロキシ安息香酸、東京化成社製
有機酸Ｉ：エイコサン二酸、東京化成社製
チクソ剤：商品名「スリパックスＨ」、日本化成社製
酸化防止剤：商品名「イルガノックス２４５」、ＢＡＳＦ社製 Next, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. The materials used in the examples and comparative examples are shown below.
((A) component)
Rosin-based resin: hydrogenated acid-modified rosin, trade name “Pine Crystal KE-604”, manufactured by Arakawa Chemical Industries, Ltd. (component (B1))
Organic acid A: 2,6-dihydroxybenzoic acid, manufactured by Tokyo Chemical Industry Co. (component (B2))
Organic acid B: succinic acid, Tokyo Kasei organic acid C: adipic acid, Tokyo Kasei organic acid D: glutaric acid, Tokyo Kasei organic acid E: pimelic acid, Tokyo Kasei organic acid F: suberic acid , Manufactured by Tokyo Kasei Co., Ltd. ((B4) component)
Organic acid G: dimer acid, trade name "UNIDYME14", manufactured by Air Brown (component (B5))
Halogen activator: trans-2,3-dibromo-2-butene-1,4-diol (TDBD)
((C1) component)
Solvent A: 1,4-butanediol (boiling point: 230 ° C.), solvent B: 1,3-butylene diol diacetate (boiling point: 232 ° C.) manufactured by Tokyo Chemical Industry Co., Ltd., solvent C: 1,5-pentane manufactured by Daicel Chemical Industries, Ltd. Diol (boiling point: 240 ° C.), solvent D: 2-ethyl-1,3-hexanediol (boiling point: 242 ° C.) manufactured by Tokyo Kasei Co., Ltd. Solvent E: 1,4-butanediol diacetate (boiling point: manufactured by Nippon Emulsifier) 232 ° C.), trade name “CELTOL 1,4-BDDA”, solvent F manufactured by Daicel Chemical Industries, Ltd .: dipropylene glycol (boiling point: 230 ° C.), solvent G manufactured by Tokyo Kasei Co., Ltd., 1,2-hexanediol (boiling point: 223 ° C.) ), Manufactured by Osaka Organic Chemical Industry Co., Ltd. ((C2) component)
Solvent H: 2,4-diethyl-1,5-pentanediol (boiling point: 300 ° C.), trade name “Kyowadiol PD-9”, solvent I: 1- (2-butoxy-1-methylethoxy) manufactured by KH Neochem ) Propan-2-ol (boiling point: 230 ° C), solvent J: Dow Chemical Company: diethylene glycol monoethyl ether acetate (boiling point: 217 ° C)
Solvent K: dipropylene glycol monopropyl ether (boiling point: 212 ° C.)
((D) component)
Solder powder: alloy composition Sn-3.0Ag-0.5Cu, particle size distribution 20-38μm, solder melting point 217-220 ° C
(Other ingredients)
Organic acid H: 2,4-dihydroxybenzoic acid, organic acid I manufactured by Tokyo Kasei Co., Ltd. I: eicosane diacid, thixotropic agent manufactured by Tokyo Kasei Co., Ltd .: trade name “Slipax H”, Nippon Kasei Co. antioxidant: trade name “IRGA” Knox 245 ", manufactured by BASF
　［実施例１］
　ロジン系樹脂４６質量％、有機酸Ａ２質量％、有機酸Ｇ８．５質量％、ハロゲン系活性剤０．５質量％、溶剤Ａ３５質量％、チクソ剤６質量％および酸化防止剤２質量％を容器に投入し、プラネタリーミキサーを用いて混合してフラックス組成物を得た。
　その後、得られたフラックス組成物１１質量％およびはんだ粉末８９質量％（合計で１００質量％）を容器に投入し、プラネタリーミキサーにて混合することではんだ組成物を調製した。 [Example 1]
Container containing 46% by mass of rosin-based resin, 2% by mass of organic acid A, 8.5% by mass of organic acid G, 0.5% by mass of halogen-based activator, 35% by mass of solvent A, 6% by mass of thixotropic agent and 2% by mass of antioxidant And mixed using a planetary mixer to obtain a flux composition.
Thereafter, 11% by mass of the obtained flux composition and 89% by mass of solder powder (100% by mass in total) were charged into a container, and mixed by a planetary mixer to prepare a solder composition.
　［実施例２～１２］
　表１に示す組成に従い各材料を配合した以外は実施例１と同様にして、はんだ組成物を得た。
　［比較例１～６］
　表１に示す組成に従い各材料を配合した以外は実施例１と同様にして、はんだ組成物を得た。 [Examples 2 to 12]
A solder composition was obtained in the same manner as in Example 1 except that each material was blended according to the composition shown in Table 1.
[Comparative Examples 1 to 6]
A solder composition was obtained in the same manner as in Example 1 except that each material was blended according to the composition shown in Table 1.
　＜はんだ組成物の評価＞
　はんだ組成物の評価（チップ脇ボール、ピン間ボール、ＱＦＮボイド、パワートランジスタ部品ボイド、極小パッドボイド）を以下のような方法で行った。得られた結果を表１に示す。
　なお、以下のような方法において、評価用基板は、次の方法で作成した。
　すなわち、チップ部品（１６０８チップ（大きさ：１．６ｍｍ×０．８ｍｍ）および１００５チップ（大きさ：１．６ｍｍ×０．８ｍｍ）、ＱＦＰ部品、ＱＦＮチップ、ＢＧＡ部品）を搭載できる基板（タムラ製作所社製の「ＳＰ－ＴＤＣ」）に、１２０μｍ厚のメタルマスクを使用して、はんだ組成物を印刷し、チップ部品６０個を搭載し、下記リフロー条件ＡおよびＢのいずれかの条件にて、リフロー炉（タムラ製作所社製）で、はんだ組成物を溶解させて、はんだ付けを行って、評価用基板を得た。
　また、リフロー条件ＡおよびＢについては、以下の通りである。
（i）リフロー条件Ａ
　プリヒート温度が１５０～１８０℃（約８０秒間）であり、温度２２０℃以上の時間が約５０秒間であり、ピーク温度が２４５℃である。
（ii）リフロー条件Ｂ
　プリヒート温度が１５０～１８０℃（約８０秒間）であり、温度２２０℃以上の時間が約５０秒間であり、ピーク温度が２３５℃である。
（１）チップ脇ボール
　リフロー条件Ａで得られた評価用基板を拡大鏡にて観察し、チップ部品の脇に発生したはんだボールの数（個／チップ）を測定した。
Ｂ：チップ当たりのはんだボールの数が、３個未満である。
Ｄ：チップ当たりのはんだボールの数が、３個以上である。
（２）ピン間ボール
　リフロー条件Ａで得られた評価用基板を拡大鏡にて観察し、ＱＦＰ部品（０．８ｍｍピッチ）のピン間に発生したはんだボールの数（個／ピン）の結果に基づいて下記の基準に従って、ピン間ボールを評価した。
Ｂ：ピン当たりのはんだボールの数が、１００個未満である。
Ｄ：ピン当たりのはんだボールの数が、１００個以上である。
（３）ＱＦＮボイド
　リフロー条件ＡおよびＢで得られた評価用基板のそれぞれについて、ＱＦＮ部品（大きさ：８ｍｍ×８ｍｍ、厚み：０．７５ｍｍ）の搭載部分をＸ線検査装置（「ＮＬＸ－５０００」、ＮＡＧＯＹＡ　ＥＬＥＣＴＲＩＣ　ＷＯＲＫＳ社製）を用いて観察した。得られた画像から、ボイド率［（ボイド面積／電極面積）×１００］を算出し、その平均値（ｎ＝４）をとった。そして、ボイド率に基づいて、下記の基準に従って、ＱＦＮボイドを評価した。
Ａ：ボイド率が、１５％未満である。
Ｂ：ボイド率が、１５％以上２０％未満である。
Ｃ：ボイド率が、２０％以上２５％未満である。
Ｄ：ボイド率が、２５％以上である。
（４）パワートランジスタ部品ボイド
　パワートランジスタ（大きさ：５．５ｍｍ×６．５ｍｍ、厚み：２．３ｍｍ、ランド：スズめっき、ランドの面積：３０ｍｍ２）を実装できる電極を有する基板上に、対応するパターンを有するメタルマスクを用い、はんだ組成物を印刷した。その後、はんだ組成物上にパワートランジスタを搭載して、リフロー条件Ａでリフローを行い、試験基板を作製した。得られた試験基板におけるはんだ接合部を、Ｘ線検査装置（「ＮＬＸ－５０００」、ＮＡＧＯＹＡ　ＥＬＥＣＴＲＩＣ　ＷＯＲＫＳ社製）を用いて観察した。そして、リフロー後のパワートランジスタでのボイドを観察し、得られた画像から、ボイド率(ボイド面積／電極面積×１００)を算出し、その平均値（Ｎ＝４）をとった。そしてボイド率に基づいて、下記の基準に従って、パワートランジスタのボイドを評価した。
Ｂ：ボイド率が、１０％未満である。
Ｃ：ボイド率が、１０％以上１３％未満である。
Ｄ：ボイド率が、１３％以上である。
（５）極小パッドボイド
　リフロー条件Ａで得られた評価用基板について、ＢＧＡ部品（大きさ：８ｍｍ×８ｍｍ、厚み：０．７５ｍｍ、ピッチ：０．５ｍｍ、パッド数：２２８）の搭載部分をＸ線検査装置（「ＮＬＸ－５０００」、ＮＡＧＯＹＡ　ＥＬＥＣＴＲＩＣ　ＷＯＲＫＳ社製）を用いて観察した。得られた画像から、ボイド率［（ボイド面積／電極面積）×１００］を算出し、その平均値（ｎ＝２２８）をとった。そして、ボイド率に基づいて、下記の基準に従って、極小パッドボイドを評価した。
Ｂ：ボイド率が、２％未満である
Ｄ：ボイド率が、２％以上である。 <Evaluation of solder composition>
The evaluation of the solder composition (chip side ball, ball between pins, QFN void, power transistor component void, micro pad void) was performed by the following method. Table 1 shows the obtained results.
In the following method, a substrate for evaluation was prepared by the following method.
That is, a board (Tamura) on which chip components (1608 chips (size: 1.6 mm × 0.8 mm) and 1005 chips (size: 1.6 mm × 0.8 mm), QFP components, QFN chips, BGA components) can be mounted. On a “SP-TDC” manufactured by Seisakusho Co., Ltd., a solder composition was printed using a metal mask having a thickness of 120 μm, and 60 chip components were mounted under any of the following reflow conditions A and B. In a reflow furnace (manufactured by Tamura Seisakusho), the solder composition was melted and soldered to obtain a substrate for evaluation.
The reflow conditions A and B are as follows.
(I) Reflow condition A
The preheat temperature is 150 to 180 ° C. (about 80 seconds), the time at a temperature of 220 ° C. or more is about 50 seconds, and the peak temperature is 245 ° C.
(Ii) Reflow condition B
The preheat temperature is 150 to 180 ° C. (about 80 seconds), the time at or above 220 ° C. is about 50 seconds, and the peak temperature is 235 ° C.
(1) Chip Side Ball The evaluation substrate obtained under the reflow condition A was observed with a magnifying glass, and the number of solder balls (sides / chip) generated on the side of the chip component was measured.
B: The number of solder balls per chip is less than three.
D: The number of solder balls per chip is three or more.
(2) Ball between pins Observation of the evaluation board obtained under the reflow condition A with a magnifying glass was performed, and the result of the number of solder balls (pins / pin) generated between the pins of the QFP component (0.8 mm pitch) was obtained. Based on the following criteria, the balls between pins were evaluated.
B: The number of solder balls per pin is less than 100.
D: The number of solder balls per pin is 100 or more.
(3) QFN Void For each of the evaluation substrates obtained under reflow conditions A and B, the mounting portion of the QFN component (size: 8 mm × 8 mm, thickness: 0.75 mm) is inspected with an X-ray inspection apparatus (“NLX-5000”). And "NAGOYA ELECTRIC WORKS"). The void ratio [(void area / electrode area) × 100] was calculated from the obtained image, and the average value (n = 4) was obtained. Then, based on the void ratio, QFN voids were evaluated according to the following criteria.
A: The void ratio is less than 15%.
B: The void ratio is 15% or more and less than 20%.
C: The void ratio is 20% or more and less than 25%.
D: The void ratio is 25% or more.
(4) Power transistor component void A power transistor (size: 5.5 mm x 6.5 mm, thickness: 2.3 mm, land: tin plating, land area: 30 mm2) is mounted on a substrate having electrodes. The solder composition was printed using a metal mask having a pattern. Thereafter, a power transistor was mounted on the solder composition, and reflow was performed under reflow conditions A, thereby producing a test substrate. The solder joints on the obtained test substrate were observed using an X-ray inspection apparatus (“NLX-5000”, manufactured by NAGOYA ELECTRIC WORKS). Then, the void in the power transistor after the reflow was observed, and the void ratio (void area / electrode area × 100) was calculated from the obtained image, and the average value (N = 4) was obtained. Then, based on the void ratio, the void of the power transistor was evaluated according to the following criteria.
B: The void ratio is less than 10%.
C: The void ratio is 10% or more and less than 13%.
D: The void ratio is 13% or more.
(5) Minimal pad void For the evaluation board obtained under the reflow condition A, the mounting portion of the BGA component (size: 8 mm × 8 mm, thickness: 0.75 mm, pitch: 0.5 mm, number of pads: 228) is set to X. Observation was performed using a line inspection apparatus (“NLX-5000”, manufactured by NAGOYA ELECTRIC WORKS). The void ratio [(void area / electrode area) × 100] was calculated from the obtained image, and the average value (n = 228) was obtained. Then, based on the void ratio, the minimum pad void was evaluated according to the following criteria.
B: Void rate is less than 2% D: Void rate is 2% or more.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１に示す結果からも明らかなように、本発明のはんだ組成物（実施例１～１２）は、チップ脇ボール、ピン間ボール、ＱＦＮボイド、パワートランジスタ部品ボイド、および極小パッドボイドの結果が良好であることが確認された。従って、本発明のはんだ組成物によれば、ボイドを十分に抑制できることが確認された。 As is clear from the results shown in Table 1, the results of the solder compositions of the present invention (Examples 1 to 12) were as follows: chip side balls, inter-pin balls, QFN voids, power transistor component voids, and micro pad voids. It was confirmed that it was good. Therefore, it was confirmed that voids can be sufficiently suppressed according to the solder composition of the present invention.
　本発明のはんだ組成物は、電子機器のプリント配線基板などの電子基板に電子部品を実装するための技術として好適に用いることができる。 は ん だ The solder composition of the present invention can be suitably used as a technique for mounting an electronic component on an electronic substrate such as a printed wiring board of an electronic device.

Claims (5)

  1. 　（Ａ）ロジン系樹脂、（Ｂ）活性剤および（Ｃ）溶剤を含有するフラックス組成物と、（Ｄ）融点が２００℃以上２５０℃以下であるはんだ粉末とを含有し、
    　前記（Ｂ）成分が、（Ｂ１）オルト位またはプロス位のみに水酸基を有する芳香族カルボン酸、（Ｂ２）アルキレン基を有し、炭素数が２～８のジカルボン酸、および、（Ｂ３）アルキル基を有し、炭素数が２～８のモノカルボン酸からなる群から選択される少なくとも１種を含有し、
    　前記（Ｃ）成分が、（Ｃ１）沸点が２２０℃以上２５０℃以下である、ジオール、または、ジオールのジアセテートを含有する
    　ことを特徴とするはんだ組成物。     (A) a flux composition containing a rosin-based resin, (B) an activator and (C) a solvent, and (D) a solder powder having a melting point of 200 ° C or more and 250 ° C or less,
    The component (B) comprises (B1) an aromatic carboxylic acid having a hydroxyl group only at the ortho or pros position, (B2) a dicarboxylic acid having an alkylene group and having 2 to 8 carbon atoms, and (B3) an alkyl. Containing at least one selected from the group consisting of monocarboxylic acids having 2 to 8 carbon atoms,
    The solder composition, wherein the component (C) contains (C1) a diol having a boiling point of 220 ° C. or higher and 250 ° C. or lower, or diacetate of a diol.
  2. 　請求項１に記載のはんだ組成物において、
    　前記（Ｃ１）成分が、１，４－ブタンジオール、１，５－ペンタンジオール、２－エチル－１，３－ヘキサンジオール、１，２－ヘキサンジオール、ジプロピレングリコール、１，４－ブタンジオールジアセテート、および１，３－ブチレンジオールジアセテートからなる群から選択される少なくとも１種である
    　ことを特徴とするはんだ組成物。     The solder composition according to claim 1,
    The component (C1) comprises 1,4-butanediol, 1,5-pentanediol, 2-ethyl-1,3-hexanediol, 1,2-hexanediol, dipropylene glycol, 1,4-butanediol A solder composition comprising at least one selected from the group consisting of acetate and 1,3-butylene diol acetate.
  3. 　請求項１に記載のはんだ組成物において、
    　前記（Ｃ１）成分の沸点が、２３０℃以上２５０℃以下である
    　ことを特徴とするはんだ組成物。     The solder composition according to claim 1,
    The solder composition, wherein the component (C1) has a boiling point of 230 ° C. or higher and 250 ° C. or lower.
  4. 　請求項１～請求項３のいずれか１項に記載のはんだ組成物において、
    　前記（Ｂ）成分が、（Ｂ４）ダイマー酸をさらに含有する
    　ことを特徴とするはんだ組成物。     The solder composition according to any one of claims 1 to 3,
    The component (B) further comprises (B4) dimer acid.
  5. 　請求項１～請求項４のいずれか１項に記載のはんだ組成物を用いたはんだ付け部を備えることを特徴とする電子基板。 (5) An electronic substrate, comprising: a soldered part using the solder composition according to any one of (1) to (4).
PCT/JP2019/034542 2018-09-27 2019-09-03 Solder composition and electronic substrate WO2020066489A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08155675A (en) * 1994-11-29 1996-06-18 Sony Corp Flux for forming solder bump
JP2014100737A (en) * 2012-11-22 2014-06-05 Tamura Seisakusho Co Ltd Solder composition for laser soldering, and printed wiring board using the same
JP2017185542A (en) * 2016-03-31 2017-10-12 株式会社タムラ製作所 Solder composition and electronic substrate

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08155675A (en) * 1994-11-29 1996-06-18 Sony Corp Flux for forming solder bump
JP2014100737A (en) * 2012-11-22 2014-06-05 Tamura Seisakusho Co Ltd Solder composition for laser soldering, and printed wiring board using the same
JP2017185542A (en) * 2016-03-31 2017-10-12 株式会社タムラ製作所 Solder composition and electronic substrate

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