Solder composition and method for manufacturing electronic substrate

Abstract

The present invention relates to a solder composition containing a flux composition containing (A) a rosin-based resin, (B) an activator, and (C) a solvent, and (E) a solder powder, the component (B) containing (B1) diglycolic acid, and the component (C) containing (C1) an alcohol compound, the alcohol compound has an alkyl chain having 12-22 carbon atoms and one hydroxyl group in one molecule, and the alkyl chain has a branched chain.

Description

Technical Field

[0001] The present invention relates to a solder composition and a method for producing an electronic substrate. Background Art

[0002] The solder composition is a mixture obtained by kneading solder powder and a flux composition (rosin resin, activator, solvent, etc.) into a paste (see Patent Document 1: Japanese Patent No. 5887330). Then, an electronic substrate is manufactured by reflow soldering using the solder composition.

[0003] By such a method for manufacturing an electronic substrate, module components such as communication modules or camera modules can be manufactured. In addition, module components are becoming smaller and smaller, and the electronic components carried also use fine 0402 chips or 0201 chips, and the mask openings are becoming more and more fine. In addition, due to the installation of closely adjacent components, the component spacing tends to become very narrow. In addition, by the miniaturization of the mask opening, the printing amount of the solder composition is also reduced, so there is a situation where it is easily affected by drying and it is difficult to maintain the adhesive force. In addition, the fine chip is prone to poor mounting due to the influence of static electricity, so it is necessary to use an ion blower to blow air when it is mounted on the substrate, which becomes easier to dry. At this time, when the adhesive force of the solder composition cannot be maintained, there is a situation where the components cannot be mounted halfway. In addition, even if the components are mounted, there is a situation where the components are blown away by the blower in the reflow oven. In addition, due to the narrowing of the component spacing, there is a risk of bridging after reflow soldering, resulting in a short circuit.

[0004] In addition, as for module components, for example, electronic components are sometimes mounted on a large electronic substrate, and after reflow, they are manufactured by being divided into hundreds of module components. Moreover, on a large electronic substrate, the average number of components on a substrate is more than 10,000, and it sometimes takes 2 to 3 hours to mount electronic components on a large electronic substrate. In such a case, the drying of the solder composition may reduce the adhesive force, resulting in the problem that the mounted electronic components cannot be maintained.

[0005] On the other hand, when the reduction in adhesiveness caused by drying is suppressed by increasing the boiling point of the solvent in the solder composition, there is a problem of reducing the heat slump of the solder composition. In addition, the reduction in heat slump tends to easily cause bridging. Thus, it is difficult to achieve both the adhesiveness and heat slump of the solder composition.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent No. 5887330 Summary of the invention

[0009] An object of the present invention is to provide a solder composition having excellent adhesive strength over a long period of time and excellent heat slump properties, and a method for producing an electronic substrate using the solder composition.

[0010] According to the present invention, there are provided a solder composition and an electronic substrate as shown below.

[0011] [1] A solder composition comprising:

[0012] A flux composition comprising (A) a rosin-based resin, (B) an activator and (C) a solvent, and

[0013] (E) solder powder,

[0014] The component (B) contains (B1) diglycolic acid,

[0015] The component (C) includes: (C1) an alcohol compound having an alkyl chain having 12 to 22 carbon atoms and one hydroxyl group in one molecule, wherein the alkyl chain has a branch.

[0016] [2] The solder composition according to [1], wherein

[0017] The alkyl chain of the component (C1) has a branch at the C-2 position.

[0018] [3] The solder composition according to [1] or [2], wherein

[0019] The soldering flux composition further contains (D) a thixotropic agent,

[0020] The component (D) contains (D1) an amide-based thixotropic agent and (D2) a dibenzylidene sorbitol-based thixotropic agent.

[0021] [4] The solder composition according to any one of [1] to [3], wherein

[0022] The component (C) further contains (C3) a dicarboxylic acid diester which is an ester of a chain saturated dicarboxylic acid having 6 to 10 carbon atoms and an alcohol having 3 to 4 carbon atoms.

[0023] [5] A solder composition comprising:

[0024] A flux composition comprising (A) a rosin-based resin, (B) an activator and (C) a solvent, and

[0025] (E) solder powder,

[0026] The component (B) contains (B1) diglycolic acid,

[0027] The component (C) contains (C3) a dicarboxylic acid diester, which is an ester of a chain saturated dicarboxylic acid having 6 to 10 carbon atoms and an alcohol having 3 to 4 carbon atoms.

[0028] [6] A method for producing an electronic substrate, which is a method for producing an electronic substrate by soldering using the solder composition described in any one of [1] to [5], wherein:

[0029] The manufacturing method comprises:

[0030] The process of coating the solder composition on an electronic substrate;

[0031] A step of disposing an electronic component on the solder composition;

[0032] A process of mounting the electronic component on the electronic substrate by heating in a reflow oven under given conditions; and

[0033] The electronic substrate is divided into sections to obtain module components.

[0034] According to the present invention, there can be provided a solder composition having excellent adhesive strength over a long period of time and excellent heat slump properties, and a method for producing an electronic substrate using the solder composition. DETAILED DESCRIPTION

[0035] The solder composition of this embodiment comprises: a flux composition comprising (A) a rosin resin, (B) an activator and (C) a solvent, and (E) a solder powder. The component (B) comprises (B1) diglycolic acid. The component (C) comprises: (C1) an alcohol compound having an alkyl chain having 12 or more and 22 or less carbon atoms and one hydroxyl group in one molecule, and the alkyl chain has a branched chain.

[0036] According to the present embodiment, a solder composition having excellent adhesive strength after a long period of time and excellent heat slump can be obtained. The reason for this is not clear, but the present inventors speculate as follows.

[0037] That is, the flux composition of the present embodiment is a so-called rosin-based flux containing (A) a rosin-based resin, and has excellent printability after a long period of time. In addition, the flux composition of the present embodiment further uses (B1) diglycolic acid and (C1) an alcohol compound in combination, wherein the alcohol compound has an alkyl chain with a carbon number of 12 or more and 22 or less and one hydroxyl group in one molecule and the alkyl chain has a branched chain. The (C1) component can improve the adhesion after a long period of time and tends to reduce the heat collapse. However, surprisingly, by combining the (B1) component with the (C1) component, the adhesion can be improved while maintaining the heat collapse. As described above, the inventors presume that the effects of the present invention can be achieved.

[0038] [Flux composition]

[0039] First, the flux composition used in the present embodiment will be described. The flux composition used in the present embodiment is a component other than solder powder in a solder composition, and contains (A) a rosin-based resin, (B) an activator, and (C) a solvent as described below.

[0040] [(A) ingredient]

[0041] As the (A) rosin resin used in the present embodiment, rosins and rosin-modified resins can be cited. As rosins, gum rosin, wood rosin and tall oil rosin can be cited. As rosin-modified resins, disproportionated rosin, polymerized rosin, hydrogenated rosin and derivatives thereof can be cited. As hydrogenated rosin, fully hydrogenated rosin, partially hydrogenated rosin, and hydrogenated products of unsaturated organic acid-modified rosins (aliphatic unsaturated monobasic acids such as (meth) acrylic acid, aliphatic unsaturated dibasic acids such as α,β-unsaturated carboxylic acids such as fumaric acid and maleic acid, unsaturated carboxylic acids with aromatic rings such as cinnamic acid, etc.) can be cited (also referred to as "hydrogenated acid-modified rosins"), etc. These rosin resins can be used alone or in combination of two or more.

[0042] The amount of component (A) is preferably 20% to 70% by mass, more preferably 30% to 65% by mass, and particularly preferably 40% to 60% by mass, relative to 100% by mass of the flux composition. When the amount of component (A) is above the lower limit, oxidation of the copper foil surface of the pad can be prevented, the surface can be easily wetted with molten solder, the so-called solderability can be improved, and solder balls can be fully suppressed. In addition, when the amount of component (A) is below the upper limit, the amount of residual flux can be fully suppressed.

[0043] [(B) ingredient]

[0044] The (B) activator used in the present embodiment needs to contain (B1) diglycolic acid. The (B1) component allows the heat slump property to be maintained even when the (C1) component is used.

[0045] The amount of component (B1) is preferably 0.1% by mass or more and 5% by mass or less, and more preferably 0.2% by mass or more and 2% by mass or less, relative to 100% by mass of the flux composition. When the amount of component (B2) is equal to or more than the lower limit, the heat collapse property tends to be further improved, while when it is equal to or less than the upper limit, the insulation property of the flux composition tends to be maintained.

[0046] The component (B) preferably further contains (B2) an organic acid other than diglycolic acid.

[0047] As the component (B1), other organic acids may be mentioned in addition to monocarboxylic acids, dicarboxylic acids, etc. These may be used alone or in combination of two or more.

[0048] Examples of the monocarboxylic acid include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, heptanoic acid, capric acid, lauric acid, myristic acid, pentadecanoic acid, palmitic acid, heptadecanoic acid, stearic acid, tuberostearic acid, eicosanoic acid, behenic acid, lignoic acid, and glycolic acid.

[0049] Examples of the dicarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, fumaric acid, maleic acid, and tartaric acid.

[0050] Examples of other organic acids include 1,2,3-propanetricarboxylic acid, 3-hydroxy-2-naphthoic acid, dimer acid, trimer acid, levulinic acid, lactic acid, acrylic acid, benzoic acid, salicylic acid, anisic acid, citric acid, and picolinic acid.

[0051] The amount of the component (B2) is preferably 0.5% by mass or more and 10% by mass or less, more preferably 1% by mass or more and 7% by mass or less, and even more preferably 2% by mass or more and 5% by mass or less, relative to 100% by mass of the flux composition. When the amount of the component (B2) is equal to or greater than the lower limit, the activation effect tends to be enhanced, while when it is equal to or less than the upper limit, the insulating properties of the flux composition tend to be maintained.

[0052] The component (B) may further contain other activators (hereinafter also referred to as component (B3)) in addition to the components (B1) and (B2) within the scope of being able to solve the technical problems of the present invention. As the component (B3), halogen activators and amine activators can be mentioned. Among them, the total amount of the components (B1) and (B2) relative to 100% by mass of the component (B) is preferably 70% by mass or more, more preferably 80% by mass or more, and particularly preferably 90% by mass or more.

[0053] The amount of the component (B) is preferably 1% by mass or more and 15% by mass or less, more preferably 2% by mass or more and 10% by mass or less, and particularly preferably 3% by mass or more and 8% by mass or less, relative to 100% by mass of the flux composition. When the amount of the component (B) is equal to or greater than the lower limit, the activation effect tends to be enhanced, while when it is equal to or less than the upper limit, the insulating properties of the flux composition tend to be maintained.

[0054] [(C) ingredient]

[0055] The (C) solvent used in this embodiment needs to contain (C1) an alcohol compound having an alkyl chain with 12 to 22 carbon atoms and one hydroxyl group in one molecule, and the alkyl chain has a branch. The (C1) component can improve the adhesive strength after a long period of time.

[0056] In the component (C1), the number of carbon atoms in the alkyl chain is preferably 16 or more and 20 or less, and particularly preferably 18. Furthermore, the alkyl chain preferably has a branch at the C-2 position.

[0057] Examples of the component (C1) include 2-hexyldecanol, isostearyl alcohol, 2-heptylundecanol, 2-octyldecanol, 2-hexyldodecanol, and 2-octyldodecanol.

[0058] The amount of component (C1) is preferably 10% by mass or more and 50% by mass or less, more preferably 15% by mass or more and 40% by mass or less, relative to 100% by mass of component (C), and more preferably 15% by mass or more and 40% by mass or less. When the amount of component (C1) is above the lower limit, the adhesive force after a long time can be further improved. On the other hand, when the amount of component (C1) is below the upper limit, the heat collapse can be maintained. From the same point of view, the amount of component (C1) is preferably 1% by mass or more and 20% by mass or less, more preferably 3% by mass or more and 15% by mass or less, and particularly preferably 5% by mass or more and 10% by mass or less, relative to 100% by mass of the flux composition.

[0059] The component (C) may contain a solvent other than the component (C1) and the component (C3) described below (hereinafter referred to as the component (C2)). Examples of the component (C2) include diethylene glycol, dipropylene glycol, triethylene glycol, isohexylene glycol, 1,5-pentanediol, 2,5-dimethyl-2,5-hexanediol, methyl carbitol, butyl carbitol, 2-ethylhexyldiethylene glycol (EHDG), phenyl glycol, hexyldiethylene glycol (DEH), tetraethylene glycol dimethyl ether, and dibutyl maleate.

[0060] The (C) component preferably contains a (C3) dicarboxylic acid diester, which is an ester formed by a chain saturated dicarboxylic acid having 6 or more and 10 or less carbon atoms and an alcohol having 3 or more and 4 or less carbon atoms. It should be noted that the inventors have found that the (C3) component plays a role roughly equivalent to that of the (C1) component. That is, the use of the (C3) component instead of the (C1) component can also play the role effect in this embodiment.

[0061] Examples of the component (C3) include diisopropyl sebacate and dibutyl adipate.

[0062] The amount of component (C3) is preferably from 1 mass % to 20 mass % with respect to 100 mass % of the flux composition, more preferably from 3 mass % to 15 mass % and particularly preferably from 5 mass % to 10 mass % from the viewpoint of adhesion after a long period of time.

[0063] When the components (C1) and (C3) are used in combination, the mass ratio of the component (C3) to the component (C1) (component (C3) / component (C1)) is preferably 1 / 10 or more and 10 or less, more preferably 1 / 4 or more and 4 or less, and particularly preferably 1 / 2 or more and 2 or less.

[0064] The amount of component (C) is preferably 10% by mass or more and 50% by mass or less, and more preferably 20% by mass or more and 40% by mass or less relative to 100% by mass of the flux composition. When the amount of the solvent is within the above range, the viscosity of the obtained solder composition can be appropriately adjusted within an appropriate range.

[0065] [(D) ingredient]

[0066] The flux composition used in this embodiment preferably further contains (D) a thixotropic agent from the viewpoint of printing slump and heating slump. In addition, the (D) component preferably contains (D1) an amide thixotropic agent and (D2) a dibenzylidene sorbitol thixotropic agent. The combination of the (D1) component and the (D2) component can further improve the heating slump.

[0067] As the component (D1), known fatty acid amides can be used.

[0068] The amount of the component (D1) added is preferably 0.5% by mass or more and 8% by mass or less, and more preferably 1% by mass or more and 6% by mass or less, based on 100% by mass of the flux composition.

[0069] As the component (D2), 1,3:2,4-bis-O-benzylidene-D-sorbitol and the like can be mentioned.

[0070] The amount of the component (D2) added is preferably 0.1% by mass or more and 3% by mass or less, and more preferably 0.5% by mass or more and 2% by mass or less, based on 100% by mass of the flux composition.

[0071] As for the component (D), from the viewpoint of printability, etc., a thixotropic agent (hereinafter also referred to as component (D3)) other than the components (D1) and (D2) may be further contained. As the component (D3) used therein, hydrogenated castor oil, kaolin, colloidal silica, organic bentonite, glass powder, etc. may be mentioned. These may be used alone or in combination of two or more.

[0072] The amount of the component (D) is preferably 2% by mass or more and 15% by mass or less, more preferably 5% by mass or more and 10% by mass or less, relative to 100% by mass of the flux composition. When the amount is less than the lower limit, thixotropy cannot be obtained and printing collapse tends to occur easily. On the other hand, when the amount exceeds the upper limit, thixotropy is too high and printing tends to be poor.

[0073] [Other ingredients]

[0074] In the flux composition used in the present embodiment, in addition to the components (A), (B), (C) and (D), other additives and other resins may be further added as needed. Examples of other additives include antioxidants, defoamers, modifiers, matting agents and foaming agents. The amount of these additives is preferably 0.01% by mass or more and 5% by mass or less relative to 100% by mass of the flux composition. Examples of other resins include acrylic resins and the like.

[0075] [Solder composition]

[0076] Next, the solder composition of the present embodiment will be described. The solder composition of the present embodiment contains the flux composition used in the present embodiment described above and (E) solder powder described below.

[0077] The amount of the flux composition to be blended is preferably 5% by mass or more and 35% by mass or less, more preferably 7% by mass or more and 15% by mass or less, and particularly preferably 8% by mass or more and 12% by mass or less, relative to 100% by mass of the solder composition. When the amount of the flux composition to be blended is less than 5% by mass (when the amount of the solder powder to be blended exceeds 95% by mass), the flux composition as a binder is insufficient, so that it tends to be difficult to mix the flux composition and the solder powder. On the other hand, when the amount of the flux composition to be blended exceeds 35% by mass (when the amount of the solder powder to be blended is less than 65% by mass), when the resulting solder composition is used, it tends to be difficult to form a sufficient solder joint.

[0078] [(E) ingredient]

[0079] The (E) solder powder used in this embodiment is preferably composed of lead-free solder powder only, but may also be lead-containing solder powder. In addition, the solder alloy in the solder powder preferably contains at least one selected from tin (Sn), copper (Cu), zinc (Zn), silver (Ag), antimony (Sb), lead (Pb), indium (In), bismuth (Bi), nickel (Ni), cobalt (Co) and germanium (Ge).

[0080] As the solder alloy in the solder powder, an alloy having tin as a main component is preferred. In addition, the solder alloy more preferably contains tin, silver and copper. In addition, the solder alloy may contain at least one of antimony, bismuth and nickel as an additive element. According to the flux composition of this embodiment, even when a solder alloy containing easily oxidizable additive elements such as antimony, bismuth and nickel is used, the generation of voids can be suppressed.

[0081] Here, the lead-free solder powder refers to a solder metal or alloy powder to which lead is not added. However, in the lead-free solder powder, lead is allowed to exist as an inevitable impurity, and in this case, the amount of lead is preferably 300 mass ppm or less.

[0082] Specific examples of lead-free solder powder alloys include Sn-Ag-Cu, Sn-Cu, Sn-Ag, Sn-Bi, Sn-Ag-Bi, Sn-Ag-Cu-Bi, Sn-Ag-Cu-Ni, Sn-Ag-Cu-Bi-Sb, Sn-Ag-Bi-In, and Sn-Ag-Cu-Bi-In-Sb.

[0083] The average particle size of the component (E) is preferably 1 μm to 20 μm, and more preferably 2 μm to 15 μm, from the viewpoint of being applicable to electronic substrates having narrow pad spacing. The average particle size can be measured by a dynamic light scattering particle size measuring device.

[0084] [Method for producing solder composition]

[0085] The solder composition of the present embodiment can be produced by mixing the flux composition described above and the (E) solder powder described above at the given ratio, and stirring and mixing them.

[0086] [Method for manufacturing electronic substrate]

[0087] Next, a method for manufacturing an electronic substrate according to the present embodiment will be described.

[0088] The manufacturing method of the electronic substrate of the present embodiment is a manufacturing method of the electronic substrate using the solder composition described above for soldering, and the method comprises: a step of coating the solder composition on the electronic substrate (coating step); a step of arranging electronic components on the solder composition (mounting step); a step of mounting the electronic components on the electronic substrate by heating under given conditions in a reflow furnace (reflow step); and a step of dividing the electronic substrate to obtain module components (dividing step).

[0089] According to the method for manufacturing an electronic substrate of the present embodiment, hundreds of module components can be manufactured from one relatively large electronic substrate.

[0090] In the coating step, the solder composition is coated on the electronic substrate. In the mounting step, the electronic component is placed on the solder composition.

[0091] Examples of the coating apparatus used here include a screen printer, a metal mask printer, a dispenser, and a jet dispenser.

[0092] In addition, the electronic substrate can be a large substrate that can be divided into hundreds of module components and can carry a large number of electronic components. The solder composition of the present embodiment described above has excellent adhesion after a long time, so even when a large number of electronic components are carried for a long time, it is possible to suppress the problem of being unable to maintain the carried electronic components.

[0093] In the reflow process, the electronic component is placed on the solder composition and heated under given conditions in a reflow furnace. The reflow process can achieve sufficient solder bonding between the electronic component and the printed circuit board. As a result, the electronic component can be mounted on the printed circuit board.

[0094] The reflow conditions can be appropriately set according to the melting point of the solder. For example, the preheating temperature is preferably 140°C or more and 200°C or less, more preferably 150°C or more and 160°C or less. The preheating time is preferably 60 seconds or more and 120 seconds or less. The peak temperature is preferably 230°C or more and 270°C or less, more preferably 240°C or more and 255°C or less. In addition, the holding time at a temperature of 220°C or more is preferably 20 seconds or more and 60 seconds or less.

[0095] In the dividing step, the electronic substrate is divided to obtain module components.

[0096] Here, the electronic substrate can be divided using a router-type substrate dividing machine, a dry slicer-type substrate dividing machine, a slicer, etc. In addition, the electronic substrate may be provided with cuts in advance.

[0097] The solder composition and the electronic substrate of the present embodiment are not limited to the above-described embodiment, and the present invention includes modifications, improvements, and the like within the scope that can achieve the object of the present invention.

[0098] For example, in the electronic substrate, a printed circuit board is bonded to an electronic component by a reflow process, but is not limited thereto. For example, a printed circuit board can be bonded to an electronic component by using a process (laser heating process) of heating a solder composition with a laser instead of the reflow process. In this case, the laser source is not particularly limited and can be suitably used according to the wavelength of the absorption band of the metal. As a laser source, for example, solid lasers (ruby, glass, YAG, etc.), semiconductor lasers (GaAs and InGaAsP, etc.), liquid lasers (pigments, etc.), and gas lasers (He-Ne, Ar, CO2 and excimer, etc.) can be cited.

[0099] Example

[0100] Next, the present invention will be described in further detail by way of examples and comparative examples, but the present invention is not limited to these examples. It should be noted that the materials used in the examples and comparative examples are as follows.

[0101] ((A) ingredient)

[0102] Rosin resin A: Hydrogenated acid-modified rosin, trade name "PINECRYSTAL KE-604", manufactured by Arakawa Chemical Industries, Ltd.

[0103] Rosin resin B: Fully hydrogenated rosin, trade name "Foral AX", manufactured by RIKA FINETECH

[0104] ((B1) ingredient)

[0105] Diglycolic acid: Diglycolic acid, manufactured by MIDORI KAGAKU

[0106] ((B2) ingredient)

[0107] Organic acid A: Malonic acid

[0108] Organic acid B: succinic acid

[0109] Organic acid C: Glutaric acid

[0110] Organic acid D: 1,2,3-propanetricarboxylic acid, manufactured by Shin Nippon Chemical Co., Ltd.

[0111] Organic acid E: 3-hydroxy-2-naphthoic acid

[0112] ((C1) ingredient)

[0113] Solvent A: 2-Hexyldecanol, manufactured by KOKYU ALCOHOL KOGYO Co., Ltd.

[0114] Solvent B: Isostearyl alcohol, manufactured by KOKYU ALCOHOL KOGYO

[0115] Solvent C: 2-octyldodecanol, manufactured by KOKYU ALCOHOL KOGYO

[0116] ((C2) ingredient)

[0117] Solvent D: Diethylene glycol monohexyl ether (hexyl diethylene glycol (DEH)), manufactured by Nippon Emulsifier Co., Ltd.

[0118] Solvent E: 2-Ethylhexyldiglycol (EHDG), manufactured by Nippon Emulsifier Co., Ltd.

[0119] Solvent F: Tetraethylene glycol dimethyl ether, trade name "HISOLVE MTEM", manufactured by Toho Chemical Industry Co., Ltd.

[0120] ((C3) ingredient)

[0121] Solvent G: Diisopropyl sebacate, manufactured by Tokyo Chemical Industry Co., Ltd.

[0122] Solvent H: Dibutyl adipate, manufactured by Tokyo Chemical Industry Co., Ltd.

[0123] ((D1) ingredient)

[0124] Thixotropic agent A: amide thixotropic agent (lauric acid amide), trade name "Diamid Y", manufactured by MITSUBISHI CHEMICAL CO., LTD.

[0125] ((D2) ingredient)

[0126] Thixotropic agent B: dibenzylidene sorbitol thixotropic agent (1,3:2,4-bis-O-benzylidene-D-sorbitol), trade name "GEL ALLD", manufactured by Shin Nippon Rika Co., Ltd.

[0127] ((D3) ingredient)

[0128] Thixotropic agent C: hydrogenated castor oil (melting point 85-87°C), trade name "Himaco", manufactured by KF TRADING

[0129] ((E) ingredient)

[0130] Solder powder: Alloy composition is Sn-3.0Ag-0.5Cu, particle size distribution is 5 to 15μm (equivalent to type 7 of IPC-J-STD-005A), solder melting point is 217 to 220℃

[0131] [Example 1]

[0132] 35 mass% of rosin resin A, 15 mass% of rosin resin B, 0.8 mass% of diglycolic acid, 0.5 mass% of organic acid A, 0.5 mass% of organic acid B, 2 mass% of organic acid C, 3 mass% of organic acid E, 10 mass% of solvent A, 23.2 mass% of solvent B, 4 mass% of thixotropic agent A, 1 mass% of thixotropic agent B and 5 mass% of thixotropic agent C were placed in a container and mixed using a planetary mixer to obtain a flux composition.

[0133] Then, 12 mass % of the obtained flux composition and 88 mass % of the solder powder (total 100 mass %) were placed in a container and mixed with a planetary mixer to prepare a solder composition.

[0134] [Examples 2 to 8]

[0135] A solder composition was obtained in the same manner as in Example 1 except that the respective materials were blended according to the composition shown in Table 1.

[0136] [Comparative Examples 1 to 8]

[0137] A solder composition was obtained in the same manner as in Example 1 except that the respective materials were blended according to the composition shown in Table 1.

[0138] <Evaluation of Solder Composition>

[0139] Evaluation of the solder composition (parts flight test, heat slump) was performed according to the following method. The obtained results are shown in Table 1.

[0140] (1) Component flight test

[0141] The solder composition was printed onto the test substrate using a 0201 chip pattern with an opening of 125μm×85μm, a 0402 chip pattern with an opening of 210μm×150μm, and a metal mask with a thickness of 25μm. In addition, air was blown to the test substrate by a circulating fan under an environment of temperature 25°C and humidity 50%RH. After 2 hours and 3 hours respectively, 200 0201 chips and 200 0402 chips were loaded. After the components were loaded, the test substrate was turned over to confirm whether the chips fell off, and the component flight test was evaluated according to the following criteria.

[0142] A: No chips fall off.

[0143] C: Chip detachment occurred.

[0144] (2) Heating slump

[0145] Using the IPC-A-20 pattern and a 100μm thick metal mask, the solder composition was printed on the ceramic substrate. Then, it was heated for 10 minutes in a hot air oven set to 150°C. Using a microscope, the bridge position was confirmed in the test pattern with a pad size of 0.2mm×2.03mm. In addition, the heating collapse was evaluated according to the following criteria. It should be noted that when a bridge is generated at a spacing of 0.30mm, a solder bridge is generated between the components during reflow, and the possibility of a short circuit in the substrate is high.

[0146] A: The minimum spacing is less than 0.15mm spacing.

[0147] B: The minimum spacing is less than 0.25mm spacing.

[0148] C: The minimum interval is 0.30 mm or more.

[0149] [Table 1]

[0150]

[0151] From the results shown in Table 1, it was clearly confirmed that all the results of the component flight test and the heat slump property in the solder compositions of the present invention (Examples 1 to 8) were good.

[0152] Therefore, it was confirmed that the solder composition according to the present invention was excellent in adhesive strength after a long period of time and excellent in heat slump property.

Claims

1. A solder composition comprising: A flux composition comprising (A) a rosin-based resin, (B) an activator and (C) a solvent, and (E) solder powder, The component (B) contains (B1) diglycolic acid, The component (C) includes: (C1) an alcohol compound having an alkyl chain having 12 to 22 carbon atoms and one hydroxyl group in one molecule, wherein the alkyl chain has a branch.

2. The solder composition according to claim 1, wherein The alkyl chain of the component (C1) has a branch at the C-2 position.

3. The solder composition according to claim 1 or 2, wherein The soldering flux composition further contains (D) a thixotropic agent, The component (D) contains (D1) an amide-based thixotropic agent and (D2) a dibenzylidene sorbitol-based thixotropic agent.

4. The solder composition according to claim 1 or 2, wherein The component (C) further contains (C3) a dicarboxylic acid diester, which is an ester of a linear saturated dicarboxylic acid having 6 to 10 carbon atoms and an alcohol having 3 to 4 carbon atoms.

5. A solder composition comprising: A flux composition comprising (A) a rosin-based resin, (B) an activator and (C) a solvent, and (E) solder powder, The component (B) contains (B1) diglycolic acid, The component (C) contains (C3) a dicarboxylic acid diester, which is an ester of a chain saturated dicarboxylic acid having 6 to 10 carbon atoms and an alcohol having 3 to 4 carbon atoms.

6. The solder composition according to claim 1 or 2, wherein The component (B) further contains (B2) an organic acid other than diglycolic acid.

7. The solder composition according to claim 6, wherein The total amount of the component (B1) and the component (B2) is 70% by mass or more relative to 100% by mass of the component (B).

8. The solder composition according to claim 1 or 2, wherein The component (C1) is at least one selected from 2-hexyldecanol, isostearyl alcohol, 2-heptylundecanol, 2-octyldecanol, 2-hexyldodecanol and 2-octyldodecanol.

9. The solder composition according to claim 1 or 2, wherein The amount of the component (A) is 20% by mass or more and 70% by mass or less relative to 100% by mass of the flux composition. The amount of the component (B) is 1% by mass or more and 15% by mass or less relative to 100% by mass of the flux composition. The amount of the component (B1) is 0.1% by mass or more and 5% by mass or less relative to 100% by mass of the flux composition. The amount of the component (C) is 10% by mass or more and 50% by mass or less relative to 100% by mass of the flux composition. The amount of the component (C1) is 10% by mass or more and 50% by mass or less relative to 100% by mass of the component (C), The flux composition is blended in an amount of 5 mass % or more and 35 mass % or less relative to 100 mass % of the solder composition.

10. A method for producing an electronic substrate, which is a method for producing an electronic substrate by soldering using the solder composition according to claim 1 or 2, wherein: The manufacturing method comprises: The process of coating the solder composition on an electronic substrate; A step of disposing an electronic component on the solder composition; A process of mounting the electronic component on the electronic substrate by heating in a reflow oven under given conditions; and The electronic substrate is divided into sections to obtain module components.

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