KR20190024866A - Flux compositions, solder paste compositions and electronic circuit boards - Google Patents

Abstract

It is an object of the present invention to provide a flux composition and a solder paste composition capable of suppressing the occurrence of voids during reflow soldering while suppressing stickiness of flux residue after soldering. In order to accomplish the object, the flux composition of the present invention is a flux composition constituting a solder paste composition by mixing with a solder alloy powder, wherein the flux composition comprises (A) a base resin, (B) an activator, (C) (D-1) an organic acid ester having neither a carboxyl group nor a hydroxyl group, wherein the organic acid ester (D-1) is used as the solvent (D) The melting point of the solder alloy constituting the solder alloy powder is not more than 50 DEG C and the amount of the organic acid ester (D-1) is not more than 180 DEG C, ) Is 10% by mass to 100% by mass with respect to the whole amount.

Description

Flux compositions, solder paste compositions and electronic circuit boards

The present invention relates to an electronic circuit board having a flux composition, a solder paste composition and a solder joint formed using the composition.

Conventionally, in order to bond an electronic component to an electronic circuit formed on a substrate such as a printed wiring board or a silicon wafer, a solder paste composition in which a flux and a solder alloy powder are mixed is printed on a substrate, (Hereinafter referred to as " reflow soldering method ") is generally used as a method of forming a solder joint portion by heating with a reflow furnace or the like.

The reflow soldering method is disadvantageous in that voids are liable to occur in the formed solder joint portions as compared with the soldering method using the solder molded in a predetermined form. The main cause of the generation of this void is that the components contained in the flux composition, especially the volatile solvent, are not discharged from the rapidly agglomerating solder when the solder alloy powder contained in the solder paste composition melts and agglomerates.

In recent years, due to miniaturization of pads accompanying miniaturization of electronic parts and increase of heat generation due to high functioning of electronic parts, voids allowed so far have influenced heat dissipation inhibition of parts and deterioration of joint reliability. For example, in the case of a chip component having a size of 3.2 mm x 1.6 mm, when two voids having a diameter of 200 mu m are generated under the electrode and two voids having a diameter of 300 mu m are generated, It is reported that the joint life of the joint is reduced by 0.85 times and 0.63 times, respectively. The occurrence of voids in the solder joint portion in this manner may significantly impair the reliability of electronic devices and electronic components.

As a method for reducing such voids, a method has been used in which a proper amount of an activator is mixed with a flux composition to be used to improve the fluidity at the time of melting the solder, thereby discharging gas generated inside the solder. However, such an activator is initiated from the time when the solder alloy powder and the flux composition are mixed, and the active power is already consumed to some extent at the use stage of the solder paste composition. Therefore, in this case, especially in the case of the electronic part having the miniaturization pad as described above, it is difficult to ensure sufficient wettability in soldering, and discharge of gas from the solder to be agglomerated becomes difficult.

As a method for solving this problem, there is a method in which an activator corresponding to the consumption of the active power by reaction with the solder alloy powder is added to the flux composition in advance to make it highly active to improve the fluidity at the time of melting the solder. However, if the activator is increased for high activity, the insulating property of the flux residue remaining on the substrate after soldering is lowered, thereby causing a short circuit between the component terminals.

As another method for reducing the generation of voids described above, there is a method of blending the flux composition with a solvent which is completely volatilized during the preheating step during heating. Usually, the solvent is used to adjust the solder paste composition to a proper viscosity and to improve the printability thereof. Thereby, when the printing of the solder paste composition on the substrate is completed, the solvent becomes an unnecessary component.

However, when such a volatile solvent is used, the solder paste composition tends to be dried on the metal mask, thereby increasing the viscosity of the solder paste in the course of the continuous printing, thereby causing clogging of openings in the metal mask and poor printing.

Further, as another method for reducing the generation of voids in reflow soldering, a method in which 70% by mass or more of the solvent contained in the flux is heated to a temperature (TG-15 temperature) at which the weight loss rate becomes 15 mass% There has been proposed a solder paste using a solvent which is 5 ° C or more higher than the melting peak temperature of the solder (see Patent Document 1). The amount of the solvent vaporized until the solder melts is at most 15% by mass or less. Therefore, since the solder paste is completely melted and the solder exhibits wettability, vaporization becomes strong, so that the solvent is likely to be discharged from the molten solder, thereby suppressing the generation of voids.

However, such a solvent may be used as a flux residue together with an unvaporized flux component other than the solvent (for example, a resin, a tin scavenger, an activator, etc.) when the solvent is only partially vaporized during reflow heating or substantially no vaporization And remains around the solder joint. Since the flux residue containing the solvent has a sticky nature, dust or dirt in the atmosphere tends to adhere to the atmosphere. Such flux residues with such dust or the like are deteriorated in insulation property, and therefore, there is a fear that the reliability thereof may be remarkably impaired.

Further, the flux residue may be removed by washing with a cleaning agent after soldering. In recent years, however, the non-cleaning type solder paste composition has been widely used from the viewpoints of cost, environment, and the like, and the solder paste composition capable of suppressing stickiness of flux residue while suppressing occurrence of voids is increasingly important.

Japanese Patent No. 4458043

It is an object of the present invention to provide a flux composition and a solder paste composition capable of suppressing stickiness of flux residue after soldering while suppressing generation of voids during reflow soldering.

(1) The flux composition of the present invention comprises a base resin, (B) an activator, (C) a tin agent, and (D) a solvent, wherein the solder paste composition is composed of a solder paste composition by mixing with a solder alloy powder (D-1) an organic acid ester having neither a carboxyl group nor a hydroxyl group as the solvent (D), wherein the weight loss rate (measured by the TG method) of the organic acid ester (D-1) (D-1) is in the range of 10 to 10% by mass with respect to the total amount of the solvent (D), and the melting point temperature of the solder alloy constituting the solder alloy powder is + By mass to 100% by mass.

(2) In the constitution described in (1) above, the weight loss rate (TG) of the organic acid ester (D-1) in the case where the melting peak temperature of the solder alloy constituting the solder alloy powder is 130 캜 or more and less than 175 캜 Method) is at least 180 ° C and less than 225 ° C.

(3) The composition according to (1) above, wherein the melting rate (TG) of the organic acid ester (D-1) in the case where the melting peak temperature of the solder alloy constituting the solder alloy powder is 175 캜 or more and less than 200 캜 Method) is not less than 180 占 폚 and less than 250 占 폚.

(4) The method according to (1) above, wherein the weight loss rate of the organic acid ester (D-1) when the melting peak temperature of the solder alloy constituting the solder alloy powder is 200 ° C or higher ) Is not less than 180 占 폚 and the melting peak temperature is not more than +50 占 폚.

(5) In the structure described in (2) above, the organic acid ester (D-1) is at least one of dimethyl adipate and dibutyl maleate.

(6) The composition according to (3), wherein the organic acid ester (D-1) is selected from the group consisting of dimethyl adipate, diisopropyl adipate, dibutyl maleate, dimethyl sebacate, diisobutyl adipate, Ethyl, and the like.

(7) The composition according to (4), wherein the organic acid ester (D-1) is selected from the group consisting of dimethyl adipate, diisopropyl adipate, dibutyl maleate, dimethyl sebacate, diisobutyl adipate, Ethyl, diisopropyl sebacate, dibutyl sebacate, and di-octyl sebacate.

(8) The composition according to any one of (1) to (7) above, wherein the base resin (A) comprises at least one of a rosin resin (A- The synthetic resin (A-2) can be obtained by mixing a rosin-based resin having an acrylic resin, a styrene-maleic acid resin, an epoxy resin, a urethane resin, a polyester resin, a phenoxy resin, a terpene resin, a polyalkylene carbonate, And a derivative compound obtained by dehydrating condensation of an acid derivative flexible alcohol compound.

(9) The solder paste composition of the present invention is characterized by comprising the flux composition according to any one of (1) to (8) and a solder alloy powder.

(10) The solder alloy powder according to the above (9), wherein the solder alloy powder contains 2 mass% or more and 3.1 mass% or less of Ag, 0 mass% or more and 1 mass% or less of Cu, 1 mass% or more and 5 mass% 0.5 to 4.5% by mass of Bi, 0.01 to 0.25% by mass of Ni, and the remainder being Sn.

(11) In the structure described in (10) above, the solder alloy powder further contains Co in an amount of 0.001 mass% or more and 0.25 mass% or less.

(12) The electronic circuit board of the present invention is characterized by having a solder joint body formed by using the solder paste composition according to any one of (9) to (11).

According to the present invention, it is possible to provide a flux composition and a solder paste composition capable of suppressing stickiness of flux residues after soldering, in particular, while suppressing generation of voids during reflow soldering.

One embodiment of the flux composition, solder paste composition and electronic circuit board of the present invention will be described in detail below. Needless to say, the present invention is not limited to these embodiments.

(1) Flux composition

The flux composition of the present embodiment comprises (A) a base resin, (B) an activator, (C) a tin agent, and (D) a solvent.

(A) Base resin

As the base resin (A), for example, it is preferable to use at least one of (A-1) a rosin-based resin and (A-2) a synthetic resin.

Examples of the rosin-based resin (A-1) include rosins such as tall oil rosin, gum rosin, and wood rosin; Rosin derivatives in which rosin is polymerized, hydrogenated, heterogenized, acrylated, maleized, esterified or subjected to phenol addition reaction; And modified rosin resins obtained by subjecting these rosin or rosin derivatives and unsaturated carboxylic acids (acrylic acid, methacrylic acid, maleic acid, fumaric acid, etc.) to a Diels-Alder reaction. Of these, a modified rosin resin is preferably used, and a hydrogenated acrylic acid modified rosin resin obtained by reacting acrylic acid with hydrogen to be added is particularly preferably used. These may be used singly or in combination of plural kinds.

The acid value of the rosin-based resin (A-1) is preferably 140 mgKOH / g to 350 mgKOH / g, and the weight average molecular weight thereof is preferably 200 MW to 1,000 MW.

Examples of the synthetic resin (A-2) include acrylic resin, styrene-maleic acid resin, epoxy resin, urethane resin, polyester resin, phenoxy resin, terpene resin, polyalkylene carbonate and rosin having a carboxyl group Based resin and a derivative compound obtained by dehydrating condensation of a dimeric acid derivative flexible alcohol compound. These may be used singly or in combination of plural kinds.

The acrylic resin is obtained, for example, by polymerizing a (meth) acrylate having an alkyl group having 1 to 20 carbon atoms or by copolymerizing a monomer containing the acrylate as a main component. Of these acrylic resins, an acrylic resin obtained by polymerizing monomers containing a monomer having two saturated alkyl groups having 2 to 20 carbon atoms, in which methacrylic acid and a carbon chain are straight-chain, is preferably used. The acrylic resin may be used singly or in combination of plural kinds.

As the epoxy resin, any thermosetting resin having a reactive epoxy group at the terminal thereof can be used. For example, bisphenol A type, bisphenol F type, bisphenol S type, biphenyl type, naphthalene type, cresol novolak type, Phenol novolak type, brominated bisphenol A type, hydrogenated bisphenol A type, bisphenol AF type, fluorene type, glycidyl ether type, glycidyl ester type, glycidylamine type, alicyclic type epoxy resin have. These may be used singly or in combination of plural kinds.

The urethane resin can be any resin as long as it can be obtained, for example, by reacting a compound having a plurality of isocyanate groups in one molecule with a polyol compound having two or more hydroxyl groups in one molecule. Among these, aliphatic and aromatic components Is preferably used. The urethane resin may be used singly or in combination of plural kinds.

Examples of the polyester resin include polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate and the like. These may be used singly or in combination of plural kinds.

Examples of the phenoxy resin include a bisphenol A type phenoxy resin and a bisphenol F type phenoxy resin. These may be used singly or in combination of plural kinds.

Examples of the polyalkylene carbonate include polyethylene carbonate, polypropylene carbonate, polybutene carbonate, polyisobutene carbonate, polypentene carbonate, polyhexene carbonate, polycyclo There may be mentioned polypropylene carbonate, polybutylene carbonate and the like, such as polytetrafluoroethylene, polytetrafluoroethylene, pentene carbonate, polycyclohexene carbonate, polycycloheptene carbonate, polycyclooctenecarbonate and polyimonenecarbonate . These may be used singly or in combination of plural kinds.

Examples of the rosin-based resin having a carboxyl group for a derivative compound (hereinafter referred to as a " rosin derivative compound ") obtained by dehydration condensation of a rosin-based resin having a carboxyl group and a dimeric acid derivative-compliant alcohol compound include tall oil rosin, Rosins such as gum rosin, wood rosin and the like; Rosin derivatives such as hydrogenated rosin, polymerized rosin, heterogenized rosin, acrylic acid modified rosin and maleic acid modified rosin, and the like, and in addition to these, rosins having a carboxyl group can be used. These may be used singly or in combination of plural kinds.

Examples of the dimeric acid derivative flexible alcohol compound include compounds derived from a dimer acid such as dimer diol, polyester polyol and polyester dimer diol, and having an alcohol group at the terminal thereof. For example, PRIPOL2033, PRIPLAST3197, PRIPLAST1838 (manufactured by Kuroda Japan K.K.) and the like can be used.

The rosin derivative compound is obtained by dehydration condensation of the rosin-based resin having a carboxyl group and the dimeric acid derivative flexible alcohol compound. As a method of this dehydration condensation, a commonly used method can be used. The weight ratio of the rosin-based resin having a carboxyl group to the dimeric acid derivative flexible alcohol compound is preferably 25:75 to 75:25.

The acid value of the synthetic resin (A-2) is preferably 0 mgKOH / g to 150 mgKOH / g, and the weight average molecular weight thereof is preferably 1,000 Mw to 30,000 Mw.

The blending amount of the base resin (A) is preferably 10% by mass or more and 60% by mass or less, more preferably 30% by mass or more and 55% by mass or less based on the whole amount of the flux composition.

When the rosin-based resin (A-1) is used alone, the blending amount thereof is preferably 10% by mass or more and 50% by mass or less, more preferably 15% by mass or more and 45% by mass or less based on the whole amount of the flux composition. By setting the blending amount of the rosin-based resin (A-1) within this range, good solderability and an appropriate flux residue amount can be obtained.

When the synthetic resin (A-2) is used alone, its blending amount is preferably 10% by mass or more and 60% by mass or less, more preferably 15% by mass or more and 50% by mass or less based on the whole amount of the flux composition.

When the rosin-based resin (A-1) and the synthetic resin (A-2) are used in combination, the blending ratio thereof is preferably 20:80 to 50:50, more preferably 25:75 to 40:60 desirable.

(B) Activator

Examples of the activator (B) include carboxylic acids, compounds containing a halogen, and the like. These may be used singly or in combination of plural kinds.

Examples of the carboxylic acids include monocarboxylic acids and dicarboxylic acids, and other organic acids.

Examples of the monocarboxylic acid include monocarboxylic acids such as propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, capric acid, lauric acid, myristic acid, pentadecylic acid, palmitic acid, Tallowuricostearic acid, arachidic acid, behenic acid, lignoceric acid, glycolic acid, and the like.

Examples of the dicarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, tartaric acid and diglycolic acid.

Examples of the other organic acids include dimer acid, levulic acid, lactic acid, acrylic acid, benzoic acid, salicylic acid, anisic acid, citric acid and picolinic acid.

These may be used singly or in combination of plural kinds.

Examples of the halogen-containing compound include, for example, a halogen compound (comparative cyclic activator) and a dissociative halogen compound (dissociative activator).

Examples of the non-salt type activator include non-salt organic compounds in which halogen atoms are bonded by a covalent bond, and examples thereof include chlorine, bromide, iodide and fluoride. Or may be a compound which binds two or more different halogen atoms thereof via a covalent bond. The compound is preferably a compound having a polar group such as a hydroxyl group such as a halogenated alcohol in order to improve solubility in an aqueous solvent. Examples of the halogenated alcohol include brominated alcohols such as 2,3-dibromopropanol, 2,3-dibromobutanediol, 1,4-dibromo-2-butanol and tribromonopentyl alcohol; Chlorinated alcohols such as 1,3-dichloro-2-propanol and 1,4-dichloro-2-butanol; Fluorinated alcohols such as 3-fluorocatechol; Other compounds similar to these can be mentioned.

Examples of the dissociative activator include a hydrochloride salt and a hydrobromide salt of a base such as amine and imidazole. Examples of the salts of hydrochloric acid and hydrobromic acid include salts of organic acids such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, n-propylamine, di-n-propylamine, Amines having relatively low carbon number such as propylamine, diisopropylamine, butylamine, dibutylamine, tributylamine, cyclohexylamine, monoethanolamine, diethanolamine, triethanolamine and the like; Imidazole, 2-methylimidazole, 2-ethylimidazole, 2-methyl-4-methylimidazole, 2-methyl-4-ethylimidazole, 2-propylimidazole, 2-propyl-4-propimidazole and the like, and hydrobromic acid salts. These may be used singly or in combination of plural kinds.

The blending amount of the activator (B) is preferably 0.1% by mass or more and 30% by mass or more, more preferably 2% by mass or more and 25% by mass or less based on the whole amount of the flux composition.

The amount of the carboxylic acid to be used in the activator (B) is preferably 1% by mass or more and 25% by mass or less, more preferably 5% by mass or more and 15% by mass or less, based on the whole amount of the flux composition. When the blending amount of the carboxylic acid is within this range, it is possible to suppress the generation of solder balls and to exhibit a good flux composition insulating property.

The blending amount of the above-mentioned cyclic activator used in the activator (B) is preferably 0.1% by mass or more and 5% by mass or less, more preferably 0.5% by mass or more and 3% by mass or less based on the whole amount of the flux composition.

The blending amount of the dissociative activator used in the activator (B) is preferably 0.1% by mass or more and 3% by mass or less, more preferably 0.3% by mass or more and 1.5% by mass or less based on the whole amount of the flux composition.

When the amines and imidazoles are separately used as the dissociative activator, the amount thereof is preferably 0.1% by mass or more and 5% by mass or less, more preferably 0.5% by mass or more and 3% by mass or less.

(C) Thick slurry

Examples of the thixotropic agent (C) include hydrogenated castor oil, saturated fatty acid amide, saturated fatty acid bisamides, oxy fatty acids, dibenzylidene sorbitol and the like. These may be used singly or in combination of plural kinds.

The blending amount of the thickener is preferably 1% by mass or more and 15% by mass or less, more preferably 3% by mass or more and 10% by mass or less based on the entire amount of the flux.

(D) Solvent

Examples of the solvent (D) include solvents such as isopropyl alcohol, ethanol, acetone, toluene, xylene, ethyl acetate, ethyl cellosolve, butyl cellosolve, hexyldiglycol, (2-ethylhexyl) , Butyl carbitol, octanediol, alpha terpineol, beta terpineol, tetraethylene glycol dimethyl ether, trimellitic acid tris (2-ethylhexyl), and bisisopropyl sebacate. These may be used singly or in combination of plural kinds.

In the flux composition of the present embodiment, it is preferable that the solvent (D) contains an organic acid ester having neither a carboxyl group nor a hydroxyl group (D-1).

As the solvent used in the flux composition, it is common to use a component containing either a carboxyl group or a hydroxyl group. The active agent in the components of the flux composition is electrolyzed when dissolved in such a solvent, whereby organic acid ions (RCOO < - >) or halide ions having negative charges are generated. The carboxyl group and the hydroxyl group are liable to be oriented around the ion, and as a result, they are solvated to cause a reaction between the solder alloy powder and the solvent.

However, since the organic acid ester (D-1) does not have any of the carboxyl group and the hydroxyl group, the flux composition of the present embodiment has no functional group which is liable to be oriented to the ion ionized from the activator (B) It is difficult to plum. Therefore, the solder paste composition using the flux composition of the present embodiment can suppress the reaction between the solder alloy powder and the activator in a non-heated storage state.

Since the flux composition containing the organic acid ester (D-1) can inhibit the reaction between the solder alloy powder and the activator (B) during storage of the solder paste composition, the activity and the amount of the active agent (B) The activation force remains even without adjustment, so that good wettability at the time of soldering is ensured and generation of voids can be suppressed.

Further, even if the organic acid ester (D-1) remains in the flux residue formed on the substrate, the organic acid ester (D-1) does not have any of the carboxyl group and the hydroxyl group as described above and therefore the hygroscopicity of the flux residue It is considered that it is difficult to affect the insulating property of the flux residue.

Further, the weight loss rate of the organic acid ester (D-1) (measured using the TG method, specifically, the TG curve was measured using a thermogravimetric-differential thermal analyzer, thereby calculating the weight loss rate. ) Is not less than 180 ° C. and the melting peak temperature of the solder alloy constituting the solder alloy + 50 ° C. or less is preferable. Such an organic acid ester (D-1) can suppress stickiness of flux residues formed on the substrate, and therefore can provide good insulating properties to the flux residues.

That is, the general reflow heating conditions of the solder paste composition are often set so that the peak temperature of the heating is 10 ° C to 50 ° C higher than the melting peak temperature of the solder.

As a result of intensive studies, the inventors of the present invention have found that the above-mentioned organic acid ester (D) having a weight loss rate of 100% or more at a temperature of 180 ° C or higher and a melting peak temperature of 50 ° C or less higher than the melting peak temperature of the solder alloy to be used D-1), the drying on the metal mask at the time of printing is less likely to occur, and stable continuous printing property can be ensured. Further, while suppressing the generation of voids under the reflow heating conditions, It was found that the stickiness of the flux residue can be suppressed.

For example, when the peak temperature of the solder alloy of the solder alloy powder used for mixing is 130 占 폚 or more and less than 175 占 폚, the temperature at which the weight loss rate of the organic acid ester (D-1) is 100% by mass is 180 Deg.] C and less than 225 [deg.] C is preferably used. Examples of such an organic acid ester (D-1) include dimethyl adipate, dibutyl maleate, and the like. These may be used singly or in combination of plural kinds.

Further, for example, when the peak temperature of the solder alloy of the solder alloy powder used for mixing is 175 占 폚 or more and less than 200 占 폚, the temperature at which the weight loss rate of the organic acid ester (D-1) 180 DEG C or more and less than 250 DEG C is preferably used. Examples of such organic acid ester (D-1) include dimethyl adipate, diisopropyl adipate, dibutyl maleate, dimethyl sebacate, diisobutyl adipate, diethyl sebacate and the like. These may be used singly or in combination of plural kinds.

Further, for example, when the peak temperature of the solder alloy of the solder alloy powder used for mixing is 205 DEG C or higher, the temperature at which the weight loss of the organic acid ester (D-1) is 100% And the melting peak temperature of the solder alloy constituting the solder alloy + 50 DEG C or lower is preferably used. Examples of such organic acid esters (D-1) include dimethyl adipate, diisopropyl adipate, dibutyl maleate, dimethyl sebacate, diisobutyl adipate, diethyl sebacate, diisopropyl sebacate, Diisobutyl sebacate, di-octyl sebacate, and the like. These may be used singly or in combination of plural kinds.

The blending amount of the solvent (D) is preferably 20% by mass or more and 65% by mass or less with respect to the total amount of the flux composition. The blending amount thereof is more preferably 20 mass% or more and 60 mass% or less, and particularly preferably 25 mass% or more and 50 mass% or less.

The amount of the organic acid ester (D-1) is preferably 10% by mass to 100% by mass with respect to the total amount of the solvent (D).

In the flux composition of the present embodiment, an additive may be added if necessary. Examples of the additive include antioxidants, antifoaming agents, surfactants, quenchers and the like. These may be used singly or in combination of plural kinds.

The blending amount of the additive is preferably 0.5 mass% or more and 20 mass% or less, more preferably 1 mass% or more and 15 mass% or less with respect to the entire flux.

(2) Solder paste composition

The solder paste composition of the present embodiment is obtained by mixing the flux composition and the solder alloy powder.

As the solder alloy powder, any of leaded and non-leaded solder alloy powders can be used. That is, the solder paste composition of the present embodiment can be produced by using the above-described organic acid ester (D-1) suitable for the melting peak temperature, regardless of the components of the solder alloy powder to be used, It is possible to suppress the stickiness of the flux residue after it.

Examples of alloys usable for the solder alloy powder include alloys containing Sn and Pb, Sn and Pb, alloys containing at least one of Ag, Bi and In, alloys containing Sn and Ag, An alloy containing Sn and Cu, an alloy containing Sn, Ag and Cu, an alloy containing Sn and Bi, and the like. A solder alloy powder in which a suitable combination of Sn, Pb, Ag, Bi, In, Cu, Zn, Ga, Sb, Au, Pd, Ge, Ni, Cr, . It is also possible to use them in combination other than the above-mentioned elements.

Among them, a powder of a solder alloy including Sb, Ag and Cu such as a Sn-Ag based solder alloy, a Sn-Ag-Cu based solder alloy and a Sn-Ag-Cu-Bi-Sb based solder alloy Is preferably used.

Among these, the use of the solder alloy powder having an alloy composition as exemplified below can improve the crack propagation inhibiting effect of the solder joint portion to be formed.

That is, the solder alloy powder contains 1 mass% to 3.1 mass% of Ag, 1 mass% or more of Cu, 0 mass% or more and 5 mass% or less of Sb, 0.5 mass% or more and 4.5 mass% or less of Bi , Ni in an amount of not less than 0.01 mass% and not more than 0.25 mass%, and the balance being Sn.

A more preferable content of Ag is 2 mass% to 3.1 mass%, a more preferable content of Cu is 0.5 mass% to 1 mass%, a more preferable content of Sb is 2 mass% to 4 mass% A more preferable content of Bi is 3.1% by mass or more and 4.5% by mass, and a more preferable content of Ni is 0.01% by mass or more and 0.15% by mass or less.

It is preferable that the solder alloy powder further contains Co in an amount of 0.001 mass% or more and 0.25 mass% or less. The content of Co is more preferably 0.001 mass% or more and 0.15 mass% or less.

By using such a solder alloy powder, the solder joint portion formed by using the solder paste composition according to the present embodiment can suppress crack propagation in the solder joint portion even in a harsh environment in which the difference in the grain boundary is large and vibration is applied. Further, even when solder bonding is performed using an electronic component that is not Ni / Pd / Au plated or Ni / Au plated, it is possible to suppress crack propagation in the vicinity of the interface between the solder joint and the bottom electrode of the electronic component .

The blending amount of the solder alloy powder is preferably 65% by mass to 95% by mass with respect to the total amount of the solder paste composition. The blending amount thereof is more preferably 85% by mass to 93% by mass, and particularly preferably 87% by mass to 92% by mass.

When the blending amount of the solder alloy powder is less than 65% by mass, sufficient solder bonding tends to be difficult to be formed when the obtained solder paste composition is used. When the content of the other solder alloy powder is more than 95% by mass, the flux composition as a binder tends to be insufficient, so that it tends to be difficult to mix the flux composition and the solder alloy powder.

The particle diameter of the solder alloy powder is preferably 1 mu m or more and 40 mu m or less, more preferably 5 mu m or more and 35 mu m or less, particularly preferably 10 mu m or more and 30 mu m or less.

The solder paste composition of the present embodiment is obtained by using the flux composition comprising the organic acid ester (D-1), which is suitable for the melting peak temperature of the solder alloy of the solder alloy powder, to suppress the generation of voids during reflow soldering, The stickiness of the residue can be suppressed.

(3) Electronic circuit board

The electronic circuit board of the present embodiment preferably has a solder joint portion formed using the above solder paste composition and a flux residue (in this specification, a solder joint portion and a flux residue together referred to as a " solder joint body "). The electronic circuit board is manufactured by forming an electrode and a solder resist film at predetermined positions on a substrate, printing a solder paste composition of the present embodiment using a mask having a predetermined pattern, Is mounted at a predetermined position, and is reflowed.

The electronic circuit board thus manufactured is provided with a solder joint portion on the electrode, and the solder joint portion electrically connects the electrode and the electronic component. On the substrate, a flux residue is adhered to at least the solder joint portion.

Since the solder paste composition and the flux residue are formed by using the solder paste composition of the present embodiment, voids are hardly generated in the solder joint portion, and the flux residue is hardly sticky. Further, by making the alloy composition of the solder alloy powder a specific element and a content, it is possible to improve the crack propagation inhibiting effect of the solder joint portion.

Example

Hereinafter, the present invention will be described in detail with reference to examples and comparative examples. The present invention is not limited to these examples.

≪ Production of synthetic resin &

200 g of diethylene glycol monohexyl ether was charged into a 500 ml four-necked flask equipped with a stirrer, a reflux tube and a nitrogen inlet tube, and the mixture was heated to 110 占 폚.

Further, 300 g of a mixture of 10 mass% of methacrylic acid, 51 mass% of 2-ethylhexyl methacrylate, and 39 mass% of lauryl acrylate was added, and dimethyl 2,2'-azobis (2-methylpropyl (Manufactured by Wako Pure Chemical Industries, Ltd.) (trade name: V-601, manufactured by Wako Pure Chemical Industries, Ltd.) was added to dissolve the solution to prepare a solution.

Subsequently, this solution was added dropwise to the above-mentioned four-necked flask over 1.5 hours. The mixture was stirred at 110 DEG C for 1 hour and then the reaction was terminated to obtain a synthetic resin (A-2) used in the examples. The weight average molecular weight of the synthetic resin (A-2) was 7,800 Mw, the acid value was 40 mgKOH / g, and the glass transition temperature was -47 占 폚.

≪ Preparation of solder paste composition >

Each of the components described in Tables 1 to 4 was kneaded to obtain each of the flux compositions relating to Examples 1 to 34 and Comparative Examples 1 to 13. Subsequently, 11 mass% of each flux composition and 89 mass% of the solder alloy powder exemplified below were kneaded to obtain respective solder paste compositions relating to Examples 1 to 34 and Comparative Examples 1 to 13. Unless otherwise stated, the numerical values set forth in Tables 1 to 4 indicate% by mass.

For the synthetic resin (A-2), the solvent-like resin prepared by the above procedure is used after the solvent is volatilized by using an evaporator. Therefore, the numerical values of the synthetic resin (A-2) shown in Tables 1 to 4 show solids in which the solvent is volatilized.

The solder alloy powder used in each of the examples and comparative examples is as follows.

Examples 1 to 20 and Comparative Examples 1 to 8: Sn-3Ag-0.5Cu solder alloy powder (melt peak temperature: 219 ° C)

Examples 21 and 22 and Comparative Example 9: Sn-10Sb (melting peak temperature: 248 ° C)

Examples 23 and 24, and Comparative Examples 10 and 11: Sn-58Bi (melting peak temperature: 139 ° C)

Examples 25 to 28 and Comparative Example 12: Sn-3.5Ag-0.5Bi-8In (melt peak temperature: 202 DEG C)

Examples 29 and 30: Sn-3Ag-0.7Cu-3.5Bi-3Sb-0.04Ni-0.01Co (melting peak temperature: 223 DEG C)

Examples 31 and 32: Sn-3Ag-0.5Cu-4.5Bi-3Sb-0.03Ni (melt peak temperature: 222 DEG C)

Examples 33 and 34: Sn-3Ag-0.5Cu-3Bi-2Sb-0.03Ni (melting peak temperature: 223 DEG C)

Comparative Example 13: Sn-0.5Ag-0.5Cu-3Bi-2Sb-0.04Ni (melting peak temperature: 228 DEG C)

A thermogravimetry-differential thermal analyzer (product name: STA7200RV, manufactured by Hitachi High-Tech Science Co., Ltd.) was used for each of the organic acid ester (D-1) components and the temperature at which the weight loss rate in the TG curve was 100 mass% Were measured and described together with the component names of Tables 1 to 4. The measurement conditions were a temperature raising rate of 10 占 폚 / min, a nitrogen gas flow rate of 200 ml / min, and a sample amount of 10 mg.

※ 1 Made by Arakawa Kagaku Kogyo Co., Ltd. Hydrogenated acid-modified rosin

* 2 Fatty acid bisamide (manufactured by Nippon Kasei Co., Ltd.)

* 3 Hindered phenolic antioxidant from BASF Japan Ltd.

<Print Recovery Test>

A glass epoxy substrate having a solder resist and an electrode (diameter: 0.25 mm) having a pattern capable of mounting a BGA having a pitch of 100 mm and a pitch of 0.5 mm and a metal mask having the same pattern as the above pattern and having a thickness of 120 탆 were prepared.

Then, each solder paste composition was printed on the substrate using the metal mask. This printing was also carried out by a method of continuously printing six kinds of the above-mentioned substrates on one solder paste composition.

After this continuous printing, each solder paste composition on the metal mask was allowed to stand for 1 hour under an environment of 25 ° C-50%.

Each solder paste composition on the metal mask was then printed on the substrate. This printing was also performed by a method of continuously printing one kind of solder paste composition using ten sheets of the above substrates.

The transfer volume ratio of an electrode portion having a diameter of 0.25 mm from the 5th to the 10th printing order on the substrate subjected to the continuous printing was measured using an image tester (product name: aspire2, manufactured by Ko Young Technology Co., Ltd.) And evaluated according to the following criteria. The results are shown in Tables 5 to 8.

&Amp; cir &amp;: The number of the transfer volume ratio 35% or less is 0

?: The number of transfer volume fractions of 35% or less is 1 to 10

?: The number of transfer volume percentages of 35% or less was 11 or more and 50 or less

X: Number of transfer volume ratio of not more than 35% was 51 or more

&Lt; Flux residue stickiness test >

A glass epoxy substrate having solder resist having a pattern of a size of 6 mm in diameter and a copper land, and a metal mask having a thickness of 150 mu m and having the same pattern as the above pattern were prepared. Subsequently, each solder paste composition was printed on the glass epoxy substrate using the metal mask, and each of the solder paste compositions was heated using a reflow furnace (trade name: TNP-538EM, manufactured by Tamura Seisakusho Co., Ltd.) did. The reflow conditions depend on the composition of the solder alloy powder used for each printed solder paste composition. The conditions are as follows. Also, the oxygen concentration in the reflow furnace is 1500 ± 500 ppm.

Examples 1 to 20 and Comparative Examples 1 to 8: The preheat was carried out at 170 ° C to 180 ° C for 90 seconds, at the peak temperature of 230 ° C, at 220 ° C or more for 30 seconds or less, at a cooling rate of 3 ° C To 8 [deg.] C / sec

Examples 21 and 22 and Comparative Example 9: The preheat was carried out at 180 ° C to 200 ° C for 90 seconds, peak temperature 265 ° C, 250 ° C or more for 30 seconds or less, and the cooling rate from peak temperature to 235 ° C, 8 ℃ / sec

Examples 23 and 24 and Comparative Examples 10 and 11: The preheat was carried out at 100 ° C to 110 ° C for 90 seconds, at the peak temperature of 160 ° C, at 150 ° C or more for 30 seconds or less, and at the peak temperature to 120 ° C for 3 ° C to 8 ° C / second

Examples 25 to 28 and Comparative Example 12: The preheat was carried out at a temperature of 150 to 170 占 폚 for 90 seconds, a peak temperature of 220 占 폚, a temperature of 210 占 폚 or more for 30 seconds or less, and a cooling rate of 3 占 폚 to 8 ℃ / sec

Examples 29 to 34: The preheat was carried out at a temperature of 170 to 180 ° C for 90 seconds, a peak temperature of 230 ° C, a temperature of 220 ° C or more for 30 seconds or less, and a cooling rate of 3 ° C to 8 ° C /

Comparative Example 13: A preheat was carried out at 170 ° C to 180 ° C for 90 seconds, a peak temperature of 240 ° C, a temperature of 230 ° C or more for 30 seconds or less, and a cooling rate of 3 ° C to 8 ° C /

After each test substrate was left at room temperature for 2 hours, a solder ball having a diameter of 300 mu m was sprinkled on the flux residue formed on each test substrate soldered with a pattern of 6 mm in diameter so that the side surface of each test substrate was parallel to the ground I gave it a shock to my desk. Thereafter, the number of solder balls attached to the flux residue on each test substrate was counted and evaluated according to the following criteria. The results are shown in Tables 5 to 8.

◎: The number of solder balls is 0

○: The number of solder balls is 1 or more and 10 or less

B: The number of solder balls is 11 or more and 30 or less

X: More than 31 solder balls were attached

&Lt; Production of Continuous Rolling Paste >

Each solder paste composition was continuously subjected to a squeegee angle of 60 °, a printing tact of 30 seconds and a stroke of 300 mm under conditions of 25 ° C-50% RH for 4 hours using a squeegee of polyurethane rubber (hardness 90) Quizzing was performed.

The sample injection amount was 500 g. Each solder paste composition thus obtained after continuous scouring is hereinafter referred to as &quot; continuous rolling paste &quot;.

<Solder ball test>

A glass epoxy substrate, and a chip component having a size of 2.0 mm x 1.2 mm were prepared. A solder resist and an electrode (1.25 mm x 1.0 mm) corresponding to the chip component were formed on the glass epoxy substrate, and a metal mask having a thickness of 150 mu m having the same pattern as that of the metal mask was used to form each solder paste composition And each continuous rolling paste were printed, and chip parts were mounted. Subsequently, each glass epoxy substrate was heated with reflow furnace (product name: TNP-538EM, manufactured by Tamura Seisakusho Co., Ltd.) to prepare test substrates. The reflow conditions depend on the composition of the solder alloy powder used for each printed solder paste composition and each continuous rolling paste. The conditions are as follows. Also, the oxygen concentration in the reflow furnace is 1500 ± 500 ppm.

EXAMPLES 1 to 20 and COMPARATIVE EXAMPLES 1 to 8: Preheats were carried out at a temperature of 170 to 190 占 폚 for 110 seconds, a peak temperature of 260 占 폚, 200 占 폚 or more for 70 seconds, 220 占 폚 or more for 60 seconds, RTI ID = 0.0 &gt; 8 C / sec &lt; / RTI &gt;

Examples 21 and 22 and Comparative Example 9: Preheating was carried out at a temperature of 180 ° C to 210 ° C for 110 seconds, a peak temperature of 290 ° C, a temperature of 230 ° C or more for 70 seconds, a temperature of 250 ° C or more for 60 seconds, The cooling rate is 3 [deg.] C to 8 [deg.] C / sec

Examples 23 and 24 and Comparative Example 10 and Comparative Example 11 A preheat was carried out at a temperature of 100 ° C to 120 ° C for 110 seconds, a peak temperature of 210 ° C, a temperature of 130 ° C or more for 70 seconds, and a temperature of 150 ° C or more for 60 seconds, The cooling rate up to &lt; RTI ID = 0.0 &gt; 150 C &lt; / RTI &

Examples 25 to 28 and Comparative Example 12: Preheating was carried out at a temperature of 150 to 180 ° C for 110 seconds, a peak temperature of 250 ° C, a temperature of 190 ° C or more for 70 seconds, a temperature of 210 ° C or more for 60 seconds, The rate is 3 [deg.] C to 8 [deg.] C / sec

Examples 29 to 34: Examples 29 to 34: The preheat was carried out at 170 ° C to 190 ° C for 110 seconds, at a peak temperature of 260 ° C, at 200 ° C or more for 70 seconds, at 220 ° C for 60 seconds and at a peak temperature to 200 ° C at 3 ° C To 8 [deg.] C / sec

Comparative Example 13: The preheating was carried out at a temperature of 170 to 190 占 폚 for 110 seconds, a peak temperature of 260 占 폚, a temperature of 200 占 폚 or more for 70 seconds, a temperature of 220 占 폚 or more for 60 seconds, ℃ / sec

Each of the test substrates was observed using an X-ray diffraction apparatus (product name: SMX-160E, manufactured by Shimadzu Seisakusho Co., Ltd.), and the number of solder balls and their diameters formed on the periphery and on the undersurface of the chip component were counted . The results are shown in Tables 5 to 8.

◎: 2.0 mm × 1.2 mm Number of balls generated per 10 chip resistances is 0

○: 2.0 mm × 1.2 mm Number of balls generated per 10 chip resistances is 1 to 5

?: 2.0 mm 占 1.2 mm The number of balls generated per 10 chip resistances was 6 or more and 10 or less

×: 2.0 mm × 1.2 mm The number of balls generated per 10 chip resistances was 11 or more

&Lt; void test >

Each test substrate was manufactured under the same conditions as the solder ball test, and the surface state thereof was observed with an X-ray diffraction device (product name: SMX-160E, Shimadzu Corporation) The ratio of the total area of voids (area ratio of voids) was measured. The occurrence of voids was determined by determining the maximum value of the area ratio of the voids in 20 lands among the test substrates, and evaluated as follows. The results are shown in Tables 5 to 8.

◎: The maximum value of the area ratio of the void is 10% or less

○: The maximum value of the area ratio of the void is more than 10% and not more than 13%

?: The maximum value of the area ratio of the void is more than 13% and not more than 20%

X: The maximum value of the area ratio of the void is more than 20%

&Lt; Crack propagation inhibition test >

(Ni / Sn plating) having a size of 3.2 mm x 1.6 mm, a solder resist having a pattern capable of mounting a chip component of this size, and an electrode (1.6 mm x 1.2 mm) A glass epoxy substrate, and a 150 mu m-thick metal mask having the same pattern were prepared.

Each solder paste composition was printed on the glass epoxy substrate using the metal mask, and the chip components were mounted on the solder paste composition.

Thereafter, each of the glass epoxy substrates was heated using Reflow (trade name: TNP-538EM, manufactured by Shimadzu Corporation) to form solder joints for electrically joining the glass epoxy substrate and the chip components to each other And the chip parts were mounted. The preheat was performed at a temperature of 170 to 190 ° C for 110 seconds and a peak temperature of 245 ° C and for a period of at least 200 ° C for 65 seconds and at a temperature of 220 ° C for 45 seconds for cooling to a peak temperature of 200 ° C The speed was set at 3 占 폚 to 8 占 폚 / second, and the oxygen concentration was set to 1500 占 500ppm.

Next, using a cold and heat impact test apparatus (product name: ES-76LMS, manufactured by Hitachi Appliances Co., Ltd.) set at conditions of -40 ° C. (30 minutes) to 125 ° C. (30 minutes) , 1,500, 2,000, 2,500, and 3,000 cycles, the respective glass epoxy substrates were exposed to each other, and then they were taken out to prepare respective test substrates.

Subsequently, the target portion of each test substrate was cut out and sealed with an epoxy resin (trade name: Epomount (subject and curing agent), Refine Tech Co., Ltd.). Further, by using a wet grinding machine (product name: TegraPol-25, manufactured by Marumoto Struers Co., Ltd.), the central section of the chip component mounted on each test board can be recognized, and cracks generated in the solder joint portion Whether or not the junction was completely traversed and ruptured was observed using a scanning electron microscope (product name: TM-1000, Hitachi High Technologies Co., Ltd.) and evaluated according to the following criteria. The results are shown in Tables 5 to 8. In addition, the number of evaluation chips in each cold / heat shock cycle was set to ten.

◎ &amp; cir &amp;: Cracks that completely cross the solder joints do not occur until 3,000 cycles

&Amp; cir &amp; &amp; cir &amp; C: Cracks completely crossing the solder joint occurred between 2,501 and 3,000 cycles

?: Cracks that completely cross the solder joint occurred between 2,001 and 2,500 cycles

DELTA: Cracks completely crossing the solder joint occurred in 2,000 cycles or less

As described above, the solder paste compositions according to Examples 1 to 34 exhibited stable continuous printability by using the organic acid ester (D-1) adjusted to the melting peak temperature of the solder alloy constituting the solder alloy powder used And it was also found that the stickiness of the flux residue after soldering can be suppressed while suppressing the occurrence of voids during reflow soldering. In addition, since they have good wettability upon reflow, generation of solder balls can be suppressed. Further, it was found that, even when continuous squeezing is performed, the reaction between the activator (B) and the solder alloy powder can be suppressed, generation of voids and solder balls can be suppressed even with continuous rolling paste.

In Examples 25 to 28 using the solder alloy powder containing In, it is possible to exert a good effect of suppressing crack growth by the effect of addition of In.

In Examples 29 to 34 in which the alloy composition of the solder alloy powder was set to a specific element and content, the generation of solder balls and voids could be sufficiently suppressed, and in the case where the In-containing solder alloy powder was used It was found that a crack propagation inhibiting effect equal to or higher than that of Comparative Example 1 can be exhibited. Such a solder paste composition can be suitably used for an electronic circuit board, which is particularly disadvantageous in an electronic circuit board for in-vehicle use, and which requires high reliability.

With respect to dioctyl sebacate in the organic acid ester (D-1) shown in Tables 1 to 4, the melting peak temperature of the solder alloy powder used therein was less than 295 DEG C, The solder alloy powder having a melting point of not less than 100 ° C and a melting point of not more than 50 ° C is used as the solder alloy powder, It is possible to suppress the occurrence of voids and to suppress the stickiness of the flux residue.

Claims (12)

1. A flux composition for constituting a solder paste composition by mixing with a solder alloy powder,
(A) a base resin, (B) an activator, (C) a tin agent, and (D) a solvent,
(D-1) an organic acid ester having neither a carboxyl group nor a hydroxyl group as the solvent (D)
The temperature at which the weight loss rate (measured by the TG method) of the organic acid ester (D-1) is 100% by mass is 180 ° C or higher and the melting peak temperature of the solder alloy constituting the solder alloy powder + ,
Wherein the blending amount of the organic acid ester (D-1) is 10% by mass to 100% by mass with respect to the total amount of the solvent (D). The method according to claim 1, wherein the weight loss rate (measured by the TG method) of the organic acid ester (D-1) in the case where the melting peak temperature of the solder alloy constituting the solder alloy powder is 130 캜 or more and less than 175 캜 100% by mass is 180 占 폚 or higher and lower than 225 占 폚. The method according to claim 1, wherein the weight loss rate (measured using the TG method) of the organic acid ester (D-1) in the case where the melting peak temperature of the solder alloy constituting the solder alloy powder is 175 캜 or more and less than 205 캜 100% by mass is 180 占 폚 or higher and lower than 255 占 폚. The method for producing a solder alloy powder according to claim 1, wherein the weight loss rate (measured by the TG method) of the organic acid ester (D-1) when the melting peak temperature of the solder alloy constituting the solder alloy powder is 205 占 폚 or higher is 100% Is 180 DEG C or higher and the melting peak temperature + 50 DEG C or lower. The flux composition according to claim 2, wherein the organic acid ester (D-1) is at least one of dimethyl adipate and dibutyl maleate. The organic acid ester (D-1) according to claim 3, wherein the organic acid ester (D-1) is at least one selected from dimethyl adipate, diisopropyl adipate, dibutyl maleate, dimethyl sebacate, diisobutyl adipate and diethyl sebacate &Lt; / RTI &gt; The organic acid ester (D-1) according to claim 4, wherein the organic acid ester (D-1) is selected from the group consisting of dimethyl adipate, diisopropyl adipate, dibutyl maleate, dimethyl sebacate, diisobutyl adipate, diethyl sebacate, diisopropyl sebacate , Dibutyl sebacate and dioctyl sebacate. &Lt; RTI ID = 0.0 &gt; 8. &lt; / RTI &gt; 8. The resin composition according to any one of claims 1 to 7, wherein the base resin (A) comprises at least one of (A-1) a rosin-based resin and (A-2)
The synthetic resin (A-2) can be obtained by mixing a rosin-based resin having an acrylic resin, a styrene-maleic acid resin, an epoxy resin, a urethane resin, a polyester resin, a phenoxy resin, a terpene resin, a polyalkylene carbonate, And a derivative compound obtained by dehydrating condensation of an acid derivative flexible alcohol compound. A solder paste composition comprising the flux composition according to any one of claims 1 to 8 and a solder alloy powder. The solder alloy powder according to claim 9, wherein the solder alloy powder contains 2 mass% or more and 3.1 mass% or less of Ag, 0 mass% or more and 1 mass% or less of Cu, 1 mass% or more and 5 mass% or less of Sb, 0.5 mass% or more 4.5% by mass or less, Ni by 0.01% by mass or more and 0.25% by mass or less, and the remainder being Sn. The solder paste composition according to claim 10, wherein the solder alloy powder further contains Co in an amount of not less than 0.001 mass% and not more than 0.25 mass%. An electronic circuit board characterized by having a solder joint body formed by using the solder paste composition according to any one of claims 9 to 11.