WO2025057387A1 - はんだ合金、ソルダペースト、接合部、接合構造体および電子制御装置 - Google Patents

はんだ合金、ソルダペースト、接合部、接合構造体および電子制御装置 Download PDF

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WO2025057387A1
WO2025057387A1 PCT/JP2023/033629 JP2023033629W WO2025057387A1 WO 2025057387 A1 WO2025057387 A1 WO 2025057387A1 JP 2023033629 W JP2023033629 W JP 2023033629W WO 2025057387 A1 WO2025057387 A1 WO 2025057387A1
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Prior art keywords
mass
joint
solder alloy
solder
less
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English (en)
French (fr)
Japanese (ja)
Inventor
貴則 嶋崎
正也 新井
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Tamura Corp
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Tamura Corp
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Priority to JP2023557267A priority Critical patent/JP7406052B1/ja
Priority to PCT/JP2023/033629 priority patent/WO2025057387A1/ja
Publication of WO2025057387A1 publication Critical patent/WO2025057387A1/ja
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    • 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
    • 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°C
    • 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
    • B23K35/36—Selection of non-metallic compositions, e.g. coatings or fluxes; Selection of soldering or welding materials, conjoint with selection of non-metallic compositions, both selections being of interest
    • B23K35/3601—Selection of non-metallic compositions, e.g. coatings or fluxes; Selection of soldering or welding materials, conjoint with selection of non-metallic compositions, both selections being of interest with inorganic compounds as principal constituents
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C12/00—Alloys based on antimony or bismuth
    • 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
    • C22C13/02—Alloys based on tin with antimony or bismuth as the next major constituent

Definitions

  • the present invention relates to a solder alloy, a solder paste, a joint, a joint structure, and an electronic control device.
  • Solder alloys are one type of joining material used to join materials together (for example, printed wiring boards and electronic components).
  • Bi is added to solder alloys to adjust the melting temperature of the solder alloy.
  • Bi is hard and brittle, which reduces the ductility of the solder alloy.
  • solder alloys for example, are provided as Bi-containing solder alloys with improved ductility.
  • a SnBiSb-based low-temperature lead-free solder characterized in that the lead-free solder is composed of, by mass percentage, 32.8-56.5% Bi, 0.7-2.2% Sb, and the remainder Sn, and the mass percentages of Bi and Sb satisfy the relational expression b 0.006a2 - 0.672a + 19.61 + c, where a indicates the mass percentage of Bi and b indicates the mass percentage of Sb, and the value range of c is -1.85 ⁇ c ⁇ 1.85, and further contains, by mass percentage, one or more of the following metal elements: 0.01-2.5%, 0.05-2.0%, 0.5-0.8% Ag, and 0.05-1% In (Patent Document 3).
  • the joints in the joining structures (herein referring to structures in which multiple joined materials are joined via joints) in electronic devices are prone to cracking due to thermal fatigue. Furthermore, because joints formed with solder alloys containing Bi tend to be brittle, the above-mentioned cracks tend to propagate rapidly within the joints.
  • the through-hole mounting method is used to bond electronic components having terminals to a printed wiring board, that is, a method in which the terminals of the electronic components are inserted into through-holes provided in the printed wiring board and the two are bonded together.
  • the molten solder hardens from the through-hole side toward the printed wiring board when cooled, forming a bond (fillet) that bonds the terminal of the electronic component in the through-hole to the land (electrode) of the printed wiring board.
  • the residual stress of the bond tends to concentrate on the land side. This residual stress and the thermal contraction of the printed wiring board in the vertical direction cause the bond to peel off from the land (this phenomenon is hereinafter referred to as "lift-off"). Lift-off is particularly likely to occur when bonding using a solder alloy containing Bi.
  • Patent Documents 1 to 3 do not disclose or suggest a solder alloy that has resistance to the above-mentioned cracks (hereinafter referred to in this specification as “heat cycle resistance”) and resistance to impact forces (hereinafter referred to in this specification as “drop impact resistance”) and can suppress the occurrence of lift-off.
  • heat cycle resistance resistance to the above-mentioned cracks
  • drop impact resistance resistance to impact forces
  • the object of the present invention is to solve the above problems by providing a solder alloy and solder paste containing Bi that has good heat cycle resistance and drop impact resistance, and can form a joint that suppresses the occurrence of lift-off.
  • the solder alloy of the present invention contains 35% by mass or more and 65% by mass or less of Bi, 0.1% by mass or more and 0.65% by mass or less of Sb, 0.05% by mass or more and 2% by mass or less of Ag, and at least one of 0.001% by mass or more and 0.1% by mass or less of Ni and Co, with the remainder being Sn and unavoidable impurities.
  • solder alloy of the present invention further contains one or more elements selected from the group consisting of P, Ga, and Ge in a total amount of 0.001% by mass or more and 0.05% by mass or less.
  • the solder alloy of the present invention preferably further contains one or more elements selected from the group consisting of Mn, Ti, Al, Cr, V, Fe, Mg, Pd, Pb, and Mo in a total amount of 0.001% by mass or more and 0.05% by mass or less.
  • the bonding material of the present invention contains a solder alloy described in any one of (1) to (3) above.
  • the solder paste of the present invention contains a powder of the solder alloy described in any one of (1) to (3) above, and a flux containing a base resin, a thixotropic agent, an activator, and a solvent.
  • the joint of the present invention is formed from a solder alloy described in any one of (1) to (3) above.
  • the joint of the present invention is formed from the joint material described in (4) above.
  • the joint of the present invention is formed from the solder paste described in (5) above.
  • the joined structure of the present invention has a first joined material, a joining portion, and a second joined material, the joining portion being a joining portion described in any one of (6) to (8) above, and the first joined material and the second joined material being joined via the joining portion.
  • the electronic control device of the present invention has the joint structure described in (9) above.
  • solder alloy and solder paste of the present invention have good heat cycle resistance and drop impact resistance even when Bi is added, and can form joints that can suppress the occurrence of lift-off.
  • solder alloy of the present embodiment contains 35% by mass or more and 65% by mass or less of Bi, 0.1% by mass or more and 0.65% by mass or less of Sb, 0.05% by mass or more and 2% by mass or less of Ag, and 0.001% by mass or more and 0.1% by mass or less of at least one of Ni and Co, with the remainder being Sn and unavoidable impurities.
  • the occurrence of the cracks described above is mainly due to shear stresses that occur repeatedly in the joint due to differences in the linear expansion coefficients between the joined materials and between the joined materials and the joint. That is, dislocations move in the slip direction on the joint surface due to shear stresses. This dislocation movement causes plastic deformation (slip deformation) of the joint, resulting in the occurrence of cracks on the joint surface. In addition, shear stresses are concentrated at the tip of the crack, which causes dislocations to move along the grain boundaries (grain boundary sliding) and the cracks to grow.
  • the solder alloy of this embodiment contains a specified amount of Sn, Bi, Sb, Ag, Ni and/or Co, which improves the strength of the joint without impairing the ductility of the joint formed, thereby suppressing the occurrence and progression of the cracks described above.
  • a part of the joint formed with the solder alloy of this embodiment has a crystal structure in which Bi and Sb atoms are embedded in Sn crystals.
  • This crystal structure suppresses the movement of dislocations caused by the shear stress and improves the strength of the joint. As a result, the plastic deformation of the joint can be suppressed, and the occurrence of the cracks can be suppressed.
  • fine intermetallic compounds of Sn--Sb, Sn--Ag, Sn--Ni and/or Sn--Co are precipitated in the joint during solidification. These fine intermetallic compounds improve the strength of the joint and suppress the occurrence of grain boundary sliding in the joint.
  • the joint formed with the solder alloy of this embodiment has the above-mentioned functions, the occurrence and propagation of the above-mentioned cracks can be suppressed even when the joint is subjected to short-term and frequent temperature changes.
  • the solder alloy of the present embodiment can improve the strength of the joint without impairing the ductility of the joint, and therefore can suppress damage to the joint caused by the action of the impact force. That is, in order to suppress the occurrence of the above-mentioned cracks and the propagation of the cracks that have occurred, it is essential that dislocations are unlikely to move within the joint. On the other hand, a joint in which dislocations are unlikely to move is likely to break because it absorbs less impact energy caused by the action of the impact force. In addition, the impact force acts on the joint from multiple directions (at least two of tension, compression, shear, bending, and torsion).
  • the joint has not only strength but also sufficient ductility.
  • the solder alloy of the present embodiment contains a predetermined amount of Sn, Bi, Sb, Ag, Ni and/or Co, which allows the above crystal structure to be formed in the joint without impairing the ductility of the joint, and the above intermetallic compounds to be precipitated, thereby achieving both strength and ductility of the joint.
  • the solder alloy of the present embodiment can provide a joint that has good resistance to the above impact force, i.e., good drop impact resistance.
  • solder alloy of this embodiment can reduce the residual stress that occurs in the joint when the solder solidifies, and can suppress the occurrence of cracks in the joint caused by the residual stress and the occurrence of the lift-off described above.
  • the solder alloy of the present embodiment contains 35% by mass or more and 65% by mass or less of Bi, which allows for solution strengthening of the joint by the dissolution of Bi in Sn without impairing the ductility of the joint, thereby providing a joint having a good balance between strength and ductility.
  • the preferred Bi content is 35% by mass or more and 60% by mass or less. Furthermore, the more preferred Bi content is 40% by mass or more and 59% by mass or less.
  • the preferred Bi content can be 50% by mass or more, or 54% by mass or more, and can also be 58% by mass or less, 56.5% by mass or less, or 56% by mass or less.
  • the solder alloy of this embodiment contains 0.1 mass % or more and 0.65 mass % or less of Sb. This allows for the solid solution strengthening of the joint by the dissolution of Sb into Sn without impairing the ductility of the joint, and also allows for the strengthening of the joint and the improvement of the ductility of the joint to be realized by precipitating and dispersing fine ⁇ -SnSb intermetallic compounds in the joint. As a result, it is possible to achieve both strength and ductility of the joint.
  • the Sb content is less than 0.1 mass%, there is a risk that the joint will not be sufficiently strengthened. Also, if the Sb content exceeds 0.65 mass%, coarse ⁇ -SnSb intermetallic compounds will crystallize as primary crystals, which may impair the ductility of the joint.
  • the preferred Sb content is 0.2 mass% or more and 0.65 mass% or less. Furthermore, the more preferred Sb content is 0.3 mass% or more and 0.65 mass% or less, and 0.4 mass% or more and 0.65 mass% or less.
  • the upper limit of Sb can also be set to 0.6 mass% or less. By setting the Sb content within this range, the ductility and strength of the joint can be further improved.
  • the solder alloy of the present embodiment contains 0.05% by mass or more and 2% by mass or less of Ag. This allows fine Ag 3 Sn intermetallic compounds to be precipitated and dispersed in the joint, thereby strengthening the joint and improving its ductility. As a result, it is possible to achieve both strength and ductility at the joint.
  • the precipitation strengthening of the joint may be insufficient, and if the Ag content exceeds 2 mass %, the Ag 3 Sn intermetallic compound may become coarse, which may impair the ductility of the joint.
  • the preferred Ag content is 0.1% by mass or more and 1.5% by mass or less.
  • the preferred Ag content can be 1% by mass or less, 0.8% by mass or less, or 0.5% by mass or less.
  • the more preferred Ag content is 0.2% by mass or more and 0.4% by mass or less.
  • the solder alloy of the present embodiment contains at least one of 0.001 mass % to 0.1 mass % of Ni and Co. This makes it possible to refine the intermetallic compounds precipitated at the interface between the joint and the joined material, and to improve the strength in the vicinity of the interface, without impairing the ductility of the joint.
  • the crack propagation (grain boundary sliding) is likely to occur near the interface between the joint and the joined materials. Therefore, in order to suppress the crack propagation near this interface, it is essential to improve the strength near the interface.
  • the impact force also tends to concentrate at the interface, so in order to suppress the occurrence of damage near the interface, it is essential that the interface has high ductility.
  • the solder alloy of the present embodiment contains at least one of Ni and Co and predetermined amounts of Sn, Bi, Sb and Ag, and therefore can improve the strength near the interface without impairing ductility, and as a result, the joint can simultaneously suppress crack growth near the interface and suppress damage due to the impact force.
  • the Ni content is preferably 0.001% by mass or more and 0.1% by mass or less.
  • the Ni content can also be 0.07% by mass or less. More preferably, the Ni content is 0.01% by mass or more and 0.06% by mass or less.
  • the Ni content can also be 0.02% by mass or more, 0.03% by mass or more, or 0.04% by mass or more.
  • the preferred content is 0.001% by mass or more and 0.1% by mass or less.
  • the Co content can also be 0.07% by mass or less.
  • a more preferred Co content is 0.01% by mass or more and 0.06% by mass or less.
  • the Co content can also be 0.02% by mass or more, 0.03% by mass or more, or 0.04% by mass or more.
  • the preferred total content is 0.001% by mass or more and 0.1% by mass or less.
  • the total content can also be 0.07% by mass or less.
  • a more preferred total content is 0.01% by mass or more and 0.06% by mass or less.
  • the total content can also be 0.02% by mass or more, 0.03% by mass or more, or 0.04% by mass or more.
  • the content of at least one of Ni and Co exceeds 0.1 mass%, there is a risk that needle-shaped substances may be easily generated in the solder alloy during the manufacturing process of the solder alloy.
  • the presence of these needle-shaped substances may inhibit the powdering, making it difficult to powder into spherical shapes.
  • the solder alloy of this embodiment may further contain at least one element selected from the group consisting of P, Ga, and Ge in a total amount of 0.001% by mass to 0.05% by mass.
  • at least one element selected from the group consisting of P, Ga, and Ge By adding at least one element selected from the group consisting of P, Ga, and Ge to the solder alloy, oxidation of the solder alloy can be suppressed and the wettability of the solder alloy can be improved, making it possible to provide a highly reliable joint.
  • the total content of one or more elements selected from the group consisting of P, Ga, and Ge exceeds 0.05 mass %, voids may occur in the joint, which may deteriorate the heat cycle resistance of the joint.
  • the solder alloy of this embodiment may further contain one or more elements selected from the group consisting of Mn, Ti, Al, Cr, V, Fe, Mg, Pd, Pb, and Mo in a total amount of 0.001 mass % or more and 0.05 mass % or less.
  • the total content of one or more selected from Mn, Ti, Al, Cr, V, Fe, Mg, Pd, Pb, and Mo exceeds 0.05 mass%, voids may be generated in the joint, and the heat cycle resistance may be deteriorated. Furthermore, when Fe is added to the solder alloy of this embodiment, if the Fe content exceeds 0.05 mass %, there is a risk that needle-shaped substances are likely to be generated in the solder alloy during the manufacturing process of the solder alloy.
  • solder alloy of this embodiment is made up of Sn and inevitable impurities.
  • the solder alloy of this embodiment may contain alloy elements other than those described above as inevitable impurities.
  • the bonding material of the present embodiment contains the solder alloy of the present embodiment, and can be used in the form of a solder paste, a solder ball, a wire, a solder preform, a flux cored solder, etc., which will be described later.
  • the form of the bonding material can be appropriately selected depending on the size, type, and application of the materials to be bonded, the solder bonding method, etc.
  • the bonding material of this embodiment contains the solder alloy of this embodiment, and thus has heat cycle resistance and drop impact resistance, and can form a bonding portion that suppresses the occurrence of lift-off.
  • solder paste of the present embodiment contains the solder alloy of the present embodiment in powder form (hereinafter referred to as "alloy powder"), and is produced, for example, by kneading the alloy powder with flux to form a paste.
  • the flux may include, for example, a base resin, a thixotropic agent, an activator, and a solvent.
  • the base resin may, for example, be a rosin-based resin; an acrylic resin obtained by polymerizing at least one monomer such as acrylic acid, methacrylic acid, various esters of acrylic acid, various esters of methacrylic acid, crotonic acid, itaconic acid, maleic acid, maleic anhydride, esters of maleic acid, esters of maleic anhydride, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, vinyl chloride, or vinyl acetate; an epoxy resin; or a phenolic resin. These may be used alone or in combination.
  • an acrylic resin obtained by polymerizing at least one monomer such as acrylic acid, methacrylic acid, various esters of acrylic acid, various esters of methacrylic acid, crotonic acid, itaconic acid, maleic acid, maleic anhydride, esters of maleic acid, esters of maleic anhydride, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, vinyl
  • thixotropic agent examples include hydrogenated castor oil, hydrogenated castor oil, bisamide-based thixotropic agents (saturated fatty acid bisamide, unsaturated fatty acid bisamide, aromatic bisamide, etc.), oxyfatty acids, dimethyldibenzylidenesorbitol, etc. These can be used alone or in combination.
  • the activators include, for example, organic acids (monocarboxylic acids, dicarboxylic acids, other organic acids), halogen-containing compounds, amine-based activators, etc. These can be used alone or in combination.
  • the solvent may be, for example, an alcohol-based solvent, a butyl cellosolve-based solvent, a glycol ether-based solvent, an ester-based solvent, or the like. These may be used alone or in combination.
  • the flux may contain an antioxidant, such as a hindered phenol-based antioxidant, a phenol-based antioxidant, a bisphenol-based antioxidant, or a polymer-type antioxidant.
  • the flux may further contain additives such as a matting agent and an antifoaming agent.
  • the blending ratio (mass%) of the alloy powder to the flux can be 65:35 to 95:5 in terms of alloy powder:flux ratio.
  • the blending ratio can be 85:15 to 93:7 or 87:13 to 92:8.
  • the particle diameter of the alloy powder can be 1 ⁇ m or more and 40 ⁇ m or less.
  • the particle diameter can also be 5 ⁇ m or more and 35 ⁇ m or less, or 10 ⁇ m or more and 30 ⁇ m or less.
  • the particle diameter of the alloy powder can be changed as appropriate.
  • the solder paste of this embodiment contains the alloy powder, which allows the formation of joints that have heat cycle resistance and drop impact resistance and suppress the occurrence of lift-off.
  • the joint of the present embodiment is formed using the solder alloy and joint material (hereinafter, unless otherwise specified, including solder paste) of the present embodiment, and joins materials to be joined together.
  • the method for forming the joint of this embodiment may be any method that can be formed using the solder alloy or the joint material of this embodiment, and any method such as a reflow method, a flow method, etc.
  • the form of the joint material to be used may also be appropriately selected depending on the size, type, and use of the materials to be joined, the method for forming the joint, etc.
  • the joined structure of the present embodiment includes a first joined material, a joining portion, and a second joined material.
  • the joining portion is the joining portion of the present embodiment, and the first joined material and the second joined material are joined via the joining portion.
  • the first and second bonded materials may be, for example, a substrate (a substrate whose surface is made of ceramic, metal, alloy, or resin and on which no electronic circuit is formed), a printed wiring board (a substrate on which an electronic circuit is formed and on which no electronic components or the like are mounted), a printed circuit board (a printed wiring board on which electronic components or the like are mounted), an electronic component, a silicon wafer, a semiconductor package, a semiconductor chip, etc. Bonded materials of different types may be combined, or bonded materials of the same type may be combined. Specific combinations include, for example, a printed wiring board and an electronic component, a printed wiring board and a semiconductor chip, a semiconductor package and a printed circuit board, and a printed wiring board and a printed wiring board.
  • the joint structure of this embodiment is produced, for example, by the following method.
  • the joining material of this embodiment is placed (applied in the case of solder paste) at a predetermined position of the first material to be joined, for example, on an electronic circuit, and the second material to be joined is placed on the joining material.
  • a predetermined heating temperature for example, a peak temperature of 200° C.
  • solder preform when used as the joining material, a solder preform having a flux applied to its surface is placed at a predetermined position on the first joining material, and the second joining material is placed on the solder preform and heated.
  • solder paste is applied to a surface of the BGA or to a predetermined position of the first material to be joined, and the second material to be joined is placed on the predetermined position of the first material to be joined and heated.
  • the joint structure of this embodiment has the joint portion of this embodiment.
  • the joint structure of this embodiment has heat cycle resistance and drop impact resistance, is less susceptible to lift-off, and can maintain high reliability.
  • the electronic control device of the present embodiment includes the joint structure of the present embodiment, and is, for example, a printed circuit board in which an electronic component and a printed wiring board are joined, which is disposed in a housing, and controls the operation of components that constitute an electronic device.
  • the electronic control device of the present embodiment includes the joining structure of the present embodiment, which allows the electronic control device of the present embodiment to have heat cycle resistance and drop impact resistance, and is also less susceptible to lift-off, thereby maintaining high reliability.
  • test piece 10 was pulled in the X direction at room temperature with a stroke of 0.72 mm/min using a bench-top precision universal testing machine (product name: Autograph AG-50kNX plus, manufactured by Shimadzu Corporation) until it broke.
  • the stroke distance when the test piece 10 broke was defined as GL1
  • the length L of the central parallel part of the test piece before tension was defined as GL0.
  • the elongation of the test piece 10 was calculated based on the following formula.
  • Elongation rate (%) (GL1 - GL0) / GL0 x 100
  • Five test pieces 10 were prepared for each type of solder alloy, and the elongation and the average value of the elongation were calculated for each according to the above procedure, and evaluated based on the following criteria. The results are shown in Tables 4 to 6.
  • solder paste was prepared by kneading a flux containing the following components with a solder alloy powder (powder particle size 20 ⁇ m to 38 ⁇ m) shown in Tables 1 to 3 in the following mixing ratios (mass %).
  • the solder alloy powder was prepared by atomization.
  • Solder alloy powder: flux 89:11 ⁇ Flux composition> Hydrogenated acid modified rosin (product name: KE-604, manufactured by Arakawa Chemical Industries, Ltd.): 49% by mass Surfactant (glutaric acid: 0.3% by mass, suberic acid: 2% by mass, malonic acid: 0.5% by mass, dodecanedioic acid: 2% by mass, dibromobutenediol: 2% by mass) Fatty acid amide (product name: Slipax ZHH, manufactured by Nippon Kasei Co., Ltd.): 6% by mass Diethylene glycol monohexyl ether: 35.2% by mass Hindered phenol-based antioxidant (product name: Irganox 245, manufactured by BASF Japan Ltd.): 3% by mass
  • the following tools were prepared: - LGA (Land Grid Array, pitch width: 0.5 mm, size: length 12 mm x width 12 mm x thickness 1 mm, number of terminals: 228 pins) Glass epoxy board (base material: FR-4, surface treatment: Cu-OSP, thickness: 1.0 mm, with a pattern capable of mounting the above LGA) - Metal mask (thickness: 100 ⁇ m, corresponding to the above pattern) For each solder paste, five of the glass epoxy substrates and 20 LGAs were used. Using the above tools and each solder paste, each test board was produced according to the following procedure, and a drop impact test was performed.
  • LGA Linear Array, pitch width: 0.5 mm, size: length 12 mm x width 12 mm x thickness 1 mm, number of terminals: 228 pins
  • Glass epoxy board base material: FR-4, surface treatment: Cu-OSP, thickness: 1.0 mm, with a pattern capable of mounting the above LGA
  • - Metal mask
  • solder paste was printed on the glass epoxy board using a metal mask.
  • Four LGAs were placed on each glass epoxy board at the designated positions on the printed solder paste. The thickness of the solder paste was adjusted by the metal mask.
  • the glass epoxy board on which the LGA was placed was then reflowed using a reflow furnace (product name: TNV-M6110CR, manufactured by Tamura Corporation) to produce a test board having an LGA, a glass epoxy board, and a joint for joining them.
  • the preheat was 100° C. to 120° C.
  • the peak temperature was 200° C.
  • the time at or above 150° C. was 60 seconds
  • the cooling rate from the peak temperature to 100° C. was 1° C. to 4° C./sec.
  • the oxygen concentration was set to 200 ⁇ 100 ppm.
  • the prepared test substrate was subjected to a drop impact test under the following conditions using a drop impact tester (product name: HDST-150J, Shin-Ei Technology Co., Ltd.). That is, in accordance with the JEDEC standard JESD22-B111, the test board was repeatedly dropped from a height where a shock waveform with an acceleration of 1,500 G and a width of 0.5 ms was applied. During the drop impact test, the electrical resistance of each joint of the test board was constantly observed, and when the resistance value exceeded 1,000 ⁇ , it was judged that the board had broken, and the number of drops until the board broke was counted.
  • a drop impact tester product name: HDST-150J, Shin-Ei Technology Co., Ltd.
  • the characteristic life is 110 times or more.
  • the characteristic life is 90 times or more and less than 110 times.
  • the characteristic life is 70 times or more and less than 90 times.
  • the characteristic life is less than 70 times.
  • solder paste was printed on the glass epoxy board using a metal mask. Then, 10 chip components were placed on each glass epoxy board at predetermined positions on the printed solder paste. The thickness of the printed solder paste was adjusted by the metal mask.
  • the glass epoxy substrate on which the chip components were placed was then reflowed using a reflow furnace (product name: TNV-M6110CR, manufactured by Tamura Corporation) to produce three mounting substrates having chip components, glass epoxy substrates, and joints for joining them.
  • the preheat was 100° C. to 120° C.
  • the peak temperature was 200° C.
  • the time at or above 150° C. was 60 seconds
  • the cooling rate from the peak temperature to 100° C. was 1° C. to 4° C./sec.
  • the oxygen concentration was set to 200 ⁇ 100 ppm.
  • each mounting board was exposed to a thermal shock cycle as follows, with one cycle being set from -40°C (30 minutes) to 125°C (30 minutes), to produce test boards a to c.
  • a target portion of each of the test substrates a to c was cut out and sealed with epoxy resin (product name: HERZOG epoxy low viscosity resin (base agent and hardener), manufactured by Herzog Japan Co., Ltd.). Then, a wet polishing machine (product name: TegraPol-25, manufactured by Marumoto Struers, Ltd.) was used to make the central cross section of each chip component mounted on each test board visible, and a scanning electron microscope (product name: TM-1000, manufactured by Hitachi High-Technologies Corporation) was used to observe the state of each joint on each of test boards a to c to check for the presence or absence of cracks that completely crossed the joints, and evaluation was performed according to the following criteria. The results are shown in Tables 4 to 6.
  • ⁇ In all of the test substrates a to c, no cracks occurred that completely crossed the joint. ⁇ : In the test substrates a and b, no cracks occurred that completely crossed the joint (in the test substrate c, a crack occurred that completely crossed the joint). ⁇ : In test substrate a, no cracks occurred that completely crossed the joint (in test substrates b and c, cracks occurred that completely crossed the joint) ⁇ : In all of the test substrates a to c, a crack occurred that completely crossed the joint.
  • solder paste was printed on the glass epoxy board using a metal mask. Then, the terminals of the connector parts were inserted into the designated through-holes in the glass epoxy board, and reflow was performed using a reflow oven (product name: TNP-538EM, manufactured by Tamura Corporation) to create a test board with a solder joint (fillet) that joins the connector parts to the glass epoxy board. The reflow was performed under the same conditions as in (2) Drop Impact Test.
  • solder alloy powder was prepared from each solder ingot under the following conditions. First, 50 g of a solder ingot, 890 g of castor oil, and 10 g of hydrogenated acid-modified rosin (product name: KE-604, manufactured by Arakawa Chemical Industries, Ltd.) were placed in a 2 L stainless steel beaker, and the mixture was continuously heated using a mantle heater.
  • a homogenizer manufactured by SMT Co., Ltd.
  • SMT Co., Ltd. a homogenizer
  • the rotation speed of the homogenizer was changed to 10,000 rpm, and the contents in the stainless steel beaker were then stirred for 5 minutes. After stirring was completed, the contents in the stainless steel beaker were cooled until the temperature reached room temperature.
  • the solder alloy powder that had settled in the castor oil was removed from the stainless steel beaker and washed with ethyl acetate to remove any attached matter. The state of the solder alloy powder was then observed at 200x magnification using a digital microscope. The observation results were evaluated based on the following criteria. The results are shown in Tables 4 to 6. ⁇ : No needle-shaped substances were generated in the solder alloy powder. ⁇ : Needle-shaped substances were generated in the solder alloy powder.
  • the solder alloy of this embodiment contains a predetermined amount of Bi, Ag, Sb, Ni, or Co and Sn, or Bi, Ag, Sb, Ni, Co and Sn, and therefore can form a joint that shows good results in any of the above (1) to (4) even when Bi is added. Furthermore, the solder alloy of this embodiment can suppress the generation of needle-shaped substances even when at least one of Ni and Co is added. In addition, the solder alloy of this embodiment can improve the strength near the interface between the joint and the joined material without impairing the ductility of the joint, so that it is possible to suppress the progression of cracks even when subjected to frequent heat cycles, and to provide a joint having good drop impact resistance.
  • the strain rate when a car collides with an object is said to be 10 -3 (s -1 ) to 10 3 (s -1 ).
  • a test piece with a GL0 of 12 mm is pulled at a stroke of 0.72 mm/min, which converts to a strain rate of 10 -3 (s -1 ).
  • the solder alloy of this embodiment can form a joint having good resistance, i.e., good strength and ductility, even when subjected to a load comparable to the strain rate experienced when an automobile collides with an object.
  • the solder alloy of this embodiment has heat cycle resistance and drop impact resistance even when Bi is added, and can form a joint that can suppress the occurrence of lift-off. Furthermore, electronic control devices and electronic equipment having such a joint can demonstrate high reliability.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Electric Connection Of Electric Components To Printed Circuits (AREA)
PCT/JP2023/033629 2023-09-14 2023-09-14 はんだ合金、ソルダペースト、接合部、接合構造体および電子制御装置 Pending WO2025057387A1 (ja)

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Citations (6)

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CN105195915A (zh) * 2015-10-30 2015-12-30 苏州优诺电子材料科技有限公司 一种低温无铅焊料合金
JP2017051984A (ja) * 2015-09-10 2017-03-16 株式会社弘輝 はんだ合金及びはんだ組成物
JP2019155471A (ja) * 2018-03-08 2019-09-19 千住金属工業株式会社 はんだ合金、はんだペースト、はんだボール、やに入りはんだおよびはんだ継手
JP2021504139A (ja) * 2017-11-22 2021-02-15 深▲チェン▼市福英達工業技術有限公司 マイクロ／ナノ粒子強化型複合はんだ及びその調製方法
CN114850725A (zh) * 2022-05-24 2022-08-05 雅拓莱焊接科技（惠州）有限公司 超薄锡铋系预成型焊环及其制备工艺
JP7161140B1 (ja) * 2022-07-22 2022-10-26 千住金属工業株式会社 はんだ合金、はんだボール、はんだペーストおよびはんだ継手

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017051984A (ja) * 2015-09-10 2017-03-16 株式会社弘輝 はんだ合金及びはんだ組成物
CN105195915A (zh) * 2015-10-30 2015-12-30 苏州优诺电子材料科技有限公司 一种低温无铅焊料合金
JP2021504139A (ja) * 2017-11-22 2021-02-15 深▲チェン▼市福英達工業技術有限公司 マイクロ／ナノ粒子強化型複合はんだ及びその調製方法
JP2019155471A (ja) * 2018-03-08 2019-09-19 千住金属工業株式会社 はんだ合金、はんだペースト、はんだボール、やに入りはんだおよびはんだ継手
CN114850725A (zh) * 2022-05-24 2022-08-05 雅拓莱焊接科技（惠州）有限公司 超薄锡铋系预成型焊环及其制备工艺
JP7161140B1 (ja) * 2022-07-22 2022-10-26 千住金属工業株式会社 はんだ合金、はんだボール、はんだペーストおよびはんだ継手

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