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WO2025164804A1 - Alliage de soudure, pâte à braser, bille de soudure, préforme de soudure, joint de soudure, circuit électronique embarqué, circuit électronique d'ecu, dispositif de circuit électronique embarqué et dispositif de circuit électronique d'ecu - Google Patents

Alliage de soudure, pâte à braser, bille de soudure, préforme de soudure, joint de soudure, circuit électronique embarqué, circuit électronique d'ecu, dispositif de circuit électronique embarqué et dispositif de circuit électronique d'ecu

Info

Publication number
WO2025164804A1
WO2025164804A1 PCT/JP2025/003328 JP2025003328W WO2025164804A1 WO 2025164804 A1 WO2025164804 A1 WO 2025164804A1 JP 2025003328 W JP2025003328 W JP 2025003328W WO 2025164804 A1 WO2025164804 A1 WO 2025164804A1
Authority
WO
WIPO (PCT)
Prior art keywords
solder
electronic circuit
less
alloy
shear strength
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/JP2025/003328
Other languages
English (en)
Japanese (ja)
Inventor
裕貴 飯島
貴大 横山
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Senju Metal Industry Co Ltd
Original Assignee
Senju Metal Industry Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Senju Metal Industry Co Ltd filed Critical Senju Metal Industry Co Ltd
Publication of WO2025164804A1 publication Critical patent/WO2025164804A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F9/00—Making metallic powder or suspensions thereof
    • 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
    • B23K35/02—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape
    • B23K35/0205—Non-consumable electrodes; C-electrodes
    • 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 degrees C
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C13/00—Alloys based on tin
    • 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 solder alloys, solder pastes, solder balls, solder preforms, solder joints, on-board electronic circuits, ECU electronic circuits, on-board electronic circuit devices, and ECU electronic circuit devices.
  • On-board electronic circuits consist of electronic components soldered to a printed circuit board.
  • On-board electronic circuits are used in devices that electrically control the engine, power steering, brakes, etc., and are extremely important safety components for the operation of a vehicle.
  • ECUs Engine Control Units
  • ECUs Engine Control Units
  • automotive electronic circuits mounted in the engine compartment can be exposed to temperatures as high as 125°C or higher when the engine is running. On the other hand, when the engine is stopped, they can be exposed to temperatures as low as -40°C or lower in cold regions. Highly reliable solder alloys are used for automotive electronic circuits that are used in such harsh environments.
  • Sn-Ag-Cu solder alloys have been used as a highly versatile solder alloy.
  • Sn-Ag-Cu solder alloys have the risk of thickening the intermetallic compound layer that forms at the joint interface, raising concerns that shear stress could cause peeling at the joint interface between the electrode and the solder alloy. For this reason, there is a demand for solder alloys that can maintain their joint strength even in harsh operating environments, and various studies have been conducted to date.
  • Patent Document 1 discloses a Sn-Ag-Cu-In-Sb-Co-Ge solder alloy, which contains In, Sb, and Co in a Sn-Ag-Cu solder alloy, as a solder alloy with high heat cycle resistance. The document explains that this solder alloy can suppress lift-off in addition to its heat cycle resistance. To achieve this effect, the document also describes the addition of In instead of Bi, which has traditionally been added to suppress the rise in melting point caused by Sb, in order to improve lift-off.
  • Patent Document 2 discloses a Sn-Ag-Cu-In-Sb-Ni-Co solder alloy as a solder alloy with high heat cycle resistance.
  • This solder alloy can suppress the occurrence of voids and lift-off in addition to heat cycle resistance.
  • the document also states that by balancing the Sb and In contents, not only can heat cycle resistance be improved, but lift-off and the occurrence of voids can also be suppressed.
  • the alloy may further contain elements such as Fe from the perspective of heat cycle resistance and suppressing void generation.
  • Patent No. 6349615 Patent No. 6420936
  • Patent Documents 1 and 2 both undergo evaluation of heat cycle resistance and lift-off.
  • Patent Document 2 also evaluates the occurrence of voids. Furthermore, the melting point is evaluated to prevent an increase in reflow temperature.
  • Patent Documents 1 and 2 do not consider shear strength or fracture modes at all, and it is difficult to say that they reflect the actual conditions when using solder joints. Because solder joints electrically connect substrates and electronic components, fractures at the joint interface should be avoided as much as possible.
  • Patent Documents 1 and 2 examine heat cycle resistance.
  • Patent Document 1 the total length of cracks at 2000 cycles is evaluated as the average value of four samples.
  • Patent Document 2 the occurrence of cracks at 3000 cycles was observed in 10 samples, and it appears that the presence or absence of cracks crossing the solder joint was evaluated.
  • Patent Document 2 The evaluation described in Patent Document 2 is thought to be able to roughly grasp cracks that completely fracture the solder joint. However, even if there are samples that do not cross the solder joint but come close to doing so, the sample will be treated as having an excellent rating. If a large number of samples out of 10 have developed cracks that come close to crossing the solder joint, it is inevitable to conclude that there are some issues, but such a group of samples will also be treated as having an excellent rating. Furthermore, the invention described in Patent Document 2 happens to evaluate cracks at 3,000 cycles, but if there is a concern that several more cycles would cause multiple cracks to cross the solder joint, it must be considered that there are still issues with heat cycle resistance.
  • Patent Documents 1 and 2 do not consider shear strength and failure mode, which are important properties for solder joints. Furthermore, as automobiles have become increasingly electrified in recent years, it is expected that the number of circuit boards installed will continue to increase, so there is an urgent need to develop solder alloys that can guarantee high levels of heat cycle resistance. Furthermore, in consideration of the heat resistance of electronic components, it is also desirable for them to exhibit melting points at the same level as conventional solder alloys.
  • the object of the present invention is to provide a solder alloy, solder paste, solder ball, solder preform, solder joint, on-board electronic circuit, ECU electronic circuit, on-board electronic circuit device, and ECU electronic circuit device that has a low melting point, high shear strength, an appropriate failure mode, and excellent heat cycle resistance.
  • solder alloys disclosed in both documents the Sn-Ag-Cu-In-Sb-Co-Ge solder alloy in Example 12 of Patent Document 1 and the Sn-Ag-Cu-In-Sb-Ni-Co-Fe solder alloy in Example 15 of Patent Document 2 both had similar shear strengths to conventional solder alloys, revealing that there is room for improvement.
  • solder alloys do not have alloy compositions designed for the purpose of improving shear strength.
  • the overall properties will generally differ, and it should be understood that the entire combination of alloying elements with a specified content is technically evaluated as a single entity.
  • the inventors therefore conducted detailed research into improving shear strength and fracture modes while suppressing an increase in melting point. As a result, they discovered that adding a specified amount of Fe to Example 12 of Patent Document 1 lowers the melting point by approximately 8 to 10°C. This is presumably because adding a specified amount of Fe to a Sn-Ag-Cu-In-Sb-Co-Ge solder alloy creates a synergistic effect with Co, further refining the structure of the solder alloy and suppressing the precipitation of coarse compounds.
  • Example 15 of Patent Document 2 had a slightly higher melting point. This is presumably because, when Ni is added to a Sn-Ag-Cu-In-Sb-Co-Fe solder alloy, a solid phase resulting from Ni begins to precipitate at higher temperatures during the solidification process. It is also believed that the low Cu content caused a slight deviation from the Sn-Ag-Cu eutectic composition, resulting in a higher melting point. Therefore, it was discovered that removing Ni from Example 15 of Patent Document 2 and increasing the Cu content by 0.1 to 0.4% lowered the melting point and significantly improved shear strength.
  • Patent Documents 1 and 2 indicate that heat cycle resistance can be demonstrated.
  • the inventors confirmed that even in the examples of each patent document, some solder alloys fractured after an extremely short cycle. This indicates a large variation in evaluation results. Therefore, even solder alloys that have been considered to have high heat cycle resistance using conventional evaluation methods include some with low heat cycle resistance, making more accurate evaluations necessary. Therefore, the inventors realized that the most effective way to evaluate heat cycle resistance is to evaluate the number of cycles to fracture using the standard deviation. By evaluating using the standard deviation, it was possible to identify solder alloys with low heat cycle resistance that had previously been overlooked, and to evaluate heat cycle resistance with greater accuracy.
  • the inventors then evaluated the heat cycle resistance by calculating the standard deviation of the number of cycles to fracture. As a result, they found that a solder alloy having each constituent element within a predetermined range has a low melting point, high shear strength, and an appropriate fracture mode, as described above, and also found that the standard deviation of the number of cycles to fracture is equal to or less than a predetermined value, thereby completing the present invention.
  • the present invention which was completed based on these findings, is as follows.
  • a solder alloy comprising, by mass%, 2.0 to 3.6% Ag, 0.6 to 0.9% Cu, 1.0 to 5.0% In, 3.0 to 5.0% Sb, 0.0010 to 0.0300% Fe, 0.0010 to 0.0500% Co, and the remainder being Sn.
  • a solder alloy characterized by having an alloy composition consisting of, in mass%, 2.0 to 3.6% Ag, 0.6 to 0.9% Cu, 1.0 to 5.0% In, 3.0 to 5.0% Sb, 0.0010 to 0.0300% Fe, 0.0010 to 0.0500% Co, and the balance being Sn.
  • solder alloy according to (0) or (1) above, wherein the alloy composition (solder alloy) further contains, by mass%, 0.100% or less in total of at least one of Zr, Ge, Ga, P, As, Pb, Zn, Mg, Cr, Ti, Mo, Pt, Pd, Au, Al, and Si.
  • solder alloy according to any one of (0) to (2) above, wherein the alloy composition (solder alloy) satisfies the following formulas (1) and (2): 0.0020 ⁇ Ag ⁇ Cu ⁇ In ⁇ Sb ⁇ Fe ⁇ Co ⁇ 0.0090 (1) 445 ⁇ In/(Ag ⁇ Cu ⁇ Sb ⁇ Fe ⁇ Co) ⁇ 3560 (2)
  • Ag, Cu, In, Sb, Fe, and Co each represent the content in mass % of the solder alloy.
  • FIG. 1 shows optical microscope photographs of the samples after measuring the shear strength, where FIG. 1(a) is Example 4, FIG. 1(b) is Comparative Example 19, and FIG. 1(c) is Comparative Example 3.
  • % in relation to the solder alloy composition means “% by mass” unless otherwise specified.
  • Solder alloy (1) Ag 2.0 to 3.6% Ag contributes to improving shear strength, optimizing the fracture mode due to Ag3Sn precipitation, lowering the melting point, and improving heat cycle resistance. If the Ag content is less than 2.0%, the amount of compound precipitation is small, resulting in a decrease in shear strength.
  • the lower limit of the Ag content is 2.0% or more, preferably 2.5% or more, more preferably 2.7% or more, and even more preferably 3.0% or more.
  • the upper limit of the Ag content is 3.6% or less, preferably 3.4% or less, and more preferably 3.2% or less.
  • Cu 0.6-0.9%
  • Cu contributes to improving shear strength, optimizing the fracture mode by controlling the amount of intermetallic compounds formed at the bonding interface, lowering the melting point, and improving heat cycle resistance. Furthermore, an appropriate content can suppress the precipitation of coarse Cu6Sn5 . If the Cu content is less than 0.6%, Cu6Sn5 does not precipitate sufficiently, resulting in poor shear strength. Furthermore, the melting point increases. The lower limit of the Cu content is 0.6% or more, preferably 0.7% or more.
  • the Cu content exceeds 0.9%, the shear strength deteriorates due to the formation of hypereutectic crystals and the precipitation of coarse Cu6Sn5 at the bonding interface. Furthermore, the fracture mode becomes the bonding interface. Furthermore, due to the deterioration of shear strength, cracks occur during heat cycle testing, the standard deviation increases, and the heat cycle resistance deteriorates.
  • the upper limit of the Cu content is 0.9% or less, preferably 0.8% or less.
  • the lower limit of the In content is 1.0% or more, preferably 1.5% or more, more preferably 2.0% or more, even more preferably 2.5% or more, and particularly preferably 3.0% or more.
  • the upper limit for the In content is 5.0% or less, preferably 4.5% or less, more preferably 4.0% or less, and even more preferably 3.5% or less.
  • Sb 3.0-5.0% Sb contributes to suppressing the rise in melting point, improving shear strength, optimizing the fracture mode, and improving heat cycle resistance. If the Sb content is less than 3.0%, the solid solution strengthening with respect to Sn and the precipitation strengthening of Sn-Sb compounds are insufficient, resulting in poor shear strength.
  • the lower limit of the Sb content is 3.0% or more, preferably 3.5% or more, more preferably 3.6% or more, even more preferably 3.8% or more, particularly preferably 3.9% or more, and most preferably 4.0% or more.
  • the upper limit for the Sb content is 5.0% or less, preferably 4.8% or less, more preferably 4.6% or less, even more preferably 4.5% or less, particularly preferably 4.3% or less, and most preferably 4.1% or less.
  • Fe 0.0010-0.0300% Fe contributes to improving shear strength, optimizing fracture mode, and improving heat cycle resistance. If the Fe content is less than 0.0010%, the effect of strengthening the interface by modifying the intermetallic compound layer formed at the interface is insufficient, resulting in poor shear strength.
  • the lower limit of the Fe content is 0.0010% or more, preferably 0.0050% or more, more preferably 0.0100% or more, even more preferably 0.0150% or more, and particularly preferably 0.0200% or more.
  • the upper limit for the Fe content is 0.0300%, preferably 0.0270%, and more preferably 0.0250%.
  • Co 0.0010-0.0500% Co contributes to suppressing the rise in melting point, improving shear strength, optimizing the fracture mode, and improving heat cycle resistance. If the Co content is less than 0.0010%, the bulk grain refinement effect is insufficient, resulting in a decrease in shear strength.
  • the lower limit of the Co content is 0.0010% or more, preferably 0.0030% or more, more preferably 0.0060% or more, and even more preferably 0.0080% or more.
  • the upper limit for the Co content is 0.0500%, preferably 0.0300%, and more preferably 0.0100%.
  • Sn The balance of the solder alloy according to the present invention is Sn.
  • unavoidable impurities may be contained. Even if unavoidable impurities are contained, the aforementioned effects are not affected.
  • Ni is preferably not contained in a Sn—Ag—Cu—In—Sb—Fe—Co solder alloy, as long as the respective contents are within the aforementioned ranges. This is because the addition of a small amount of Ni rapidly increases the melting point.
  • Mn is preferably not contained in the present invention, as it increases the melting point, deteriorates wettability, prevents the formation of suitable compounds, and reduces shear strength.
  • Bi forms a Sn—In—Bi low-melting-point phase when coexisting with In.
  • the low-melting-point phase has a low melting point that makes a room-temperature environment a high-temperature environment, making it prone to creep deformation and reducing strength. Therefore, it is preferable not to contain Bi in the present invention.
  • solder alloy according to the present invention may contain at least one of Zr, Ge, Ga, P, As, Pb, Zn, Mg, Cr, Ti, Mo, Pt, Pd, Au, Al, and Si in a total content of 0.100% or less as an optional element, to the extent that the effects of the present invention are not impaired.
  • the total content is 0.080% or less.
  • the lower limit of the content is not particularly limited, but may be 0.0001% or more, and may be 0.001% or more.
  • Equation (1) takes into consideration the balance of the additive elements in the solder alloy of the present invention.
  • the solder alloy of the present invention is able to exhibit a low melting point, high shear strength, appropriate fracture mode, and high heat cycle resistance through the synergistic effects of each constituent element. Therefore, if the balance of all constituent elements except Sn is further optimized, all of the effects of the present invention can be further improved.
  • the contents of Ag, Cu, In, and Sb are approximately 10 to 100 times the contents of Fe and Co. However, their contribution to the solder alloy is considered to be about the same. Therefore, in order to further improve the low melting point, high shear strength, appropriate fracture mode, and high heat cycle resistance simultaneously in a single composition in the present invention, it is preferable to maintain a balanced content.
  • Equation (2) takes into account the balance between In and other elements among the additive elements of the solder alloy of the present invention. Compared to other additive elements, In, whether below the lower limit or above the upper limit of the content range, results in poor shear strength and an inappropriate fracture mode. This is a phenomenon unique to the Sn-Ag-Cu-In-Sb-Co-Fe solder alloy of the present invention. The reason for this is unclear, but it is presumed that reduced wettability results in insufficient wetting and spreading, and that the effect of solid solution strengthening is insufficient.
  • the numerical values themselves are used in the measured values of the alloy compositions shown in Tables 1 and 2 below. That is, in calculating the formulas (1) and (2), all digits less than the number of significant figures in the measured values shown in Tables 1 and 2 below are treated as zeros. For example, if the measured Co content is "0.008" mass%, the Co content used in calculating the formulas (1), (2), and (2) is treated as "0.008000" rather than having a range of 0.0075 to 0.0084%. In formula (1), calculations are made to the fifth decimal place, and the fifth decimal place is rounded to the fourth decimal place.
  • formula (2) calculations are made to the first decimal place, and the first decimal place is rounded to the first decimal place to obtain the last decimal place. The same applies when formulas (1) and (2) are calculated from alloy compositions specifically disclosed in patent documents and other documents mentioned in this specification.
  • alloys do not have individual constituent elements that function individually, but rather all the constituent elements form a single entity as a whole, and therefore it is rare for one element to simultaneously exhibit all of the excellent effects. For this reason, as mentioned above, in order to achieve even better properties within the optimal content range of each constituent element, it is necessary to consider the constituent elements as a whole.
  • the solder alloy of the present invention in order to achieve an even higher level of a low melting point, high shear strength, appropriate fracture mode, and high heat cycle resistance all with a single composition, it is preferable for formulas (1) and (2) to be satisfied.
  • the lower limit of formula (1) is preferably 0.0020 or more, more preferably 0.0021 or more, even more preferably 0.0022 or more, still more preferably 0.0023 or more, particularly preferably 0.0024 or more, and most preferably 0.0028 or more, 0.0029 or more, 0.0033 or more, 0.0034 or more, 0.0035 or more, 0.0036 or more, 0.0038 or more, 0.0042 or more, 0.0043 or more, 0.0045 or more, 0.0046 or more, 0.0048 or more, 0.0049 or more, 0.0050 or more, or 0.0057 or more.
  • the upper limit of formula (1) is preferably 0.0090 or less, more preferably 0.0086 or less, even more preferably 0.085 or less, still more preferably 0.0083 or less, particularly preferably 0.0076 or less, and most preferably 0.0073 or less, 0.0071 or less, 0.0069 or less, 0.0068 or less, 0.0067 or less, 0.0066 or less, 0.0065 or less, 0.0064 or less, 0.0061 or less, or 0.0060 or less.
  • the lower limit of formula (2) is preferably 445 or more, more preferably 525 or more, even more preferably 630 or more, even more preferably 700 or more, particularly preferably 787 or more, and most preferably 788 or more, 840 or more, 1050 or more, 1225 or more, 1260 or more, 1261 or more, 1313 or more, 1378 or more, 1379 or more, 1400 or more, 1401 or more, 1470 or more, 1471 or more, or 1488 or more.
  • the upper limit of formula (2) is preferably 3560 or less, more preferably 3501 or less, even more preferably 3151 or less, even more preferably 2801 or less, particularly preferably 2679 or less, and most preferably 2678 or less, 2626 or less, 2450 or less, 2451 or less, 2363 or less, 2143 or less, 2142 or less, 2101 or less, 2100 or less, 1970 or less, 1969 or less, 1891 or less, 1890 or less, 1838 or less, 1786 or less, 1785 or less, 1751 or less, 1750 or less, 1681 or less, 1680 or less, 1576 or less, or 1575 or less.
  • a rating of " ⁇ " indicates that the result is particularly preferable in practical use compared to " ⁇ .”
  • " ⁇ ” indicates a more favorable result than conventional results, and therefore falls within the scope of the present invention if other evaluation results are also excellent, and is treated as an example.
  • " ⁇ ” indicates an insufficient result for the present invention, and therefore falls outside the scope of the present invention, and is treated as a comparative example.
  • the heat cycle resistance in this invention takes into account the variation between samples after heat cycle testing, and the smaller the deviation from the average value, the higher the evaluation. For this reason, its meaning is significantly different from the evaluation of heat cycle resistance that has traditionally been considered, which simply compares average values.
  • solder paste according to the present invention is a mixture of solder powder having the above-described alloy composition and flux.
  • the flux used in the present invention is not particularly limited as long as it allows for soldering by conventional methods. Therefore, it is sufficient to use a flux containing a suitable blend of commonly used rosin, organic acid, activator, thixotropic agent, and solvent.
  • the blending ratio of the metal powder component and the flux component in the present invention is not particularly limited, but is preferably 70 to 90 mass% of the metal powder component and 10 to 30 mass% of the flux component.
  • solder alloy according to the present invention can be used as solder balls.
  • the solder alloy according to the present invention can be manufactured using a dropping method, which is a common method in the industry.
  • a solder joint can be manufactured by processing the solder balls using a common method in the industry, such as by mounting one solder ball on an electrode coated with flux and joining the solder balls.
  • the particle size of the solder balls is preferably 1 ⁇ m or more, more preferably 10 ⁇ m or more, even more preferably 20 ⁇ m or more, and particularly preferably 30 ⁇ m or more.
  • the upper limit of the particle size of the solder balls is preferably 3000 ⁇ m or less, more preferably 1000 ⁇ m or less, even more preferably 800 ⁇ m or less, and particularly preferably 600 ⁇ m or less.
  • solder alloy according to the present invention can be used as a preform, which may be in the form of a washer, ring, pellet, disk, ribbon, wire, or the like.
  • solder joint is suitable for use in joining at least two or more members to be joined.
  • the members to be joined are not particularly limited, as long as they are electrically connected using the solder alloy according to the present invention, and include, for example, elements, substrates, electronic components, printed circuit boards, insulating substrates, heat sinks, lead frames, semiconductors using electrode terminals, power modules, inverter products, etc.
  • Joining using the solder alloy of the present invention can be performed in the usual way, for example using the reflow method.
  • the melting temperature of the solder alloy when performing reflow soldering can be approximately 20°C higher than the liquidus temperature.
  • the cooling rate during solidification will allow for an even finer alloy structure.
  • the solder joint can be cooled at a cooling rate of 2-3°C/s or more. Other joining conditions can be adjusted as appropriate depending on the alloy composition of the solder alloy.
  • the solder alloy according to the present invention has a suppressed increase in melting point, excellent shear strength, an appropriate fracture mode, and excellent heat cycle resistance. Therefore, even when used in automobiles, which are exposed to harsh environments, i.e., when used on-board, fracture of soldered joints is suppressed with uniformity. Therefore, because it has such particularly outstanding properties, it can be seen that the solder alloy according to the present invention is particularly suitable for soldering electronic circuits mounted on automobiles.
  • excellent heat cycle resistance means that, as shown in the examples below, a heat cycle test is conducted in which the temperature is held at -40°C and +125°C for 10 minutes each, and the standard deviation of the number of cycles required for the electrical resistance of the soldered joint to increase by 20% from before the heat cycle test is 1,000 or less. These characteristics mean that even when used under extremely harsh conditions such as those in the heat cycle test, the possibility of breakage of the on-board electronic circuitry is minimized, and no unusable or malfunctioning will occur.
  • solder alloy of the present invention is more particularly used for soldering on-board electronic circuits or ECU electronic circuits, and exhibits excellent heat cycle resistance.
  • An "electronic circuit” is a system that performs a desired function as a whole through the electronic engineering combination of multiple electronic components, each with its own function.
  • Examples of electronic components that make up such electronic circuits include chip resistor components, multi-resistor components, QFP, QFN, power transistors, diodes, capacitors, etc. Electronic circuits incorporating these electronic components are mounted on a substrate to form electronic circuit devices.
  • the substrate that constitutes such an electronic circuit device such as a printed wiring board
  • the substrate that constitutes such an electronic circuit device is not particularly limited. Its material is also not particularly limited, but examples include heat-resistant plastic substrates (e.g., FR-4, which has a high Tg and low CTE).
  • a preferred printed wiring board is one in which the Cu land surface has been treated with an organic substance such as amine or imidazole (OSP: Organic Surface Protection).
  • solder alloy according to the present invention can be manufactured using low alpha dose materials as its raw materials. When such low alpha dose alloys are used to form solder bumps around memory, they can suppress soft errors.
  • each temperature was determined from the DSC curve.
  • the DSC curve was obtained by raising the temperature at 5°C/min in the atmosphere using a Seiko Instruments DSC (Model: 6200).
  • the liquidus temperature was determined from the obtained DSC curve and used as the melting point. If the melting point is 232°C or less, reflow soldering can be performed at temperatures similar to conventional ones. If the melting point is above 232°C, conventional reflow soldering cannot be performed due to the high melting point.
  • solder alloys shown in Tables 1 and 2 were cast to prepare solder sheets (diameter: 1 mm, thickness: 0.15 mm).
  • a reflow furnace (SNR-615: manufactured by Senju Metal Industry Co., Ltd.) was used to solder chip resistors to Cu-OSP electrodes on an FR-4 substrate.
  • the chip resistors used were 3216CR (CR32-114JV: manufactured by Hokuriku Electric Industry Co., Ltd.).
  • the reflow profile consisted of holding the temperature at 220°C or higher for 40 seconds in a nitrogen atmosphere, with a peak temperature of 245°C.
  • Example 4 from Table 1 and Comparative Example 19 from Table 2 were selected, and each solder alloy was atomized to prepare solder powder.
  • a solder paste of each solder alloy was prepared by mixing with a soldering flux ("GLV” manufactured by Senju Metal Industry Co., Ltd.) consisting of rosin, solvent, activator, thixotropic agent, organic acid, etc.
  • the alloy powder of the solder paste was 88% by mass, and the flux was 12% by mass.
  • the solder paste was printed on a 0.8 mm thick printed circuit board (material: FR-4) using a 100 ⁇ m thick metal mask, and then a 12 mm x 12 mm LGA (Land Grid Array) component was mounted using a mounter. Reflow soldering was performed using the same reflow profile as in "(2) (2-1)" above to prepare samples. Fifteen samples were prepared for Example 4, and 14 samples were prepared for Comparative Example 18.
  • the prepared samples were placed in a heat cycle tester (TSA-101L-A, manufactured by Espec Corporation) set at a low temperature of -40°C, a high temperature of +125°C, and a holding time of 10 minutes, and the resistance value was measured during the test. A 20% increase from the initial resistance value was considered to have caused breakage, and the average number of cycles at breakage and the standard deviation were calculated. When the standard deviation was 1000 or less, it was evaluated as having a degree of variation that was not problematic for practical use. On the other hand, when the standard deviation was more than 1000, samples were present that were far from the average value, and therefore the variation was evaluated as being impractical.
  • the evaluation results of (1) to (3) are shown in Tables 1 and 2.
  • the evaluation results of (4) are shown in Table 3.
  • Examples 1 to 62 all had appropriate amounts of each constituent element, resulting in practically acceptable results in all evaluations. Furthermore, Examples 1 to 8, 10 to 17, 19 to 24, 27 to 31, 38, 39, 42, 43, and 46 to 62, which satisfied formulas (1) and (2), were found to show extremely excellent results in all evaluations. These were results that were significantly superior, even among those that were practically acceptable.
  • Comparative Example 1 did not contain In, Sb, Fe, or Co, and therefore had poor shear strength and an inappropriate fracture mode.
  • Comparative Example 2 had poor shear strength due to the low Ag content.
  • Comparative Examples 3 and 4 had high Ag contents, and therefore had poor shear strength and an inappropriate fracture mode.
  • Comparative Examples 5 and 6 had poor shear strength due to the low Cu content.
  • Comparative Example 6 had an inappropriate fracture mode due to the inclusion of Ni.
  • Comparative Example 7 had a high Cu content, resulting in poor shear strength and an inappropriate fracture mode.
  • Comparative Examples 8 and 9 the In content was inappropriate, resulting in poor shear strength and an inappropriate fracture mode.
  • the Sb content was low, resulting in poor shear strength.
  • the Sb content was high, resulting in poor shear strength and an inappropriate fracture mode.
  • Comparative Examples 12 to 14 had poor shear strength due to the low Fe content. Comparative Example 15 had poor shear strength due to the high Fe content, and the failure mode was inappropriate.
  • Comparative Example 16 had poor shear strength due to the low Co content. Comparative Example 17 had poor shear strength and an inappropriate fracture mode due to the high Co content.
  • Comparative Examples 18 and 20 contained Ni or Mn, respectively, resulting in a significantly increased melting point, poor shear strength, and an inappropriate fracture mode. Comparative Example 19 contained Bi, resulting in poor shear strength.
  • Example 4 there was only one sample with small variations in the heat cycle test and a small difference from the average value. It was found that similar results were also observed in the other Examples. On the other hand, in Comparative Example 19, there was a large variation in the heat cycle test and there were samples with an extremely large difference from the average value.
  • Figure 1 shows optical microscope photographs of samples after shear strength measurement, with Figure 1(a) being Example 4, Figure 1(b) being Comparative Example 19, and Figure 1(c) being Comparative Example 3.
  • Example 4 the solder joint was found to have fractured due to bulk fracture.
  • Comparative Example 19 the solder joint was found to have fractured due to both bulk fracture and fracture in the intermetallic compound at the joint interface.
  • Comparative Example 3 the solder joint was found to have fractured in the intermetallic compound at the joint interface. Therefore, it was found that the fracture mode was appropriate in this Example 4. Similar results were obtained in the other Examples.
  • the solder of the present invention can be used in on-board electronic circuits such as ECUs, which are electronic circuits that control automobiles using computers to improve fuel efficiency, but it can also be used in consumer electronic devices such as personal computers with excellent results.
  • ECUs electronic circuits that control automobiles using computers to improve fuel efficiency

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacture Of Metal Powder And Suspensions Thereof (AREA)
  • Powder Metallurgy (AREA)
  • Conductive Materials (AREA)
  • Electric Connection Of Electric Components To Printed Circuits (AREA)

Abstract

La présente invention concerne un alliage de soudure, une pâte à braser, une bille de soudure, une préforme de soudure, un joint de soudure, un circuit électronique embarqué, un circuit électronique d'ECU, un dispositif de circuit électronique embarqué, et un dispositif de circuit électronique d'ECU qui ont un point de fusion bas, ont une résistance au cisaillement élevée, présentent un mode de fracture approprié, et ont une excellente résistance au cycle thermique. L'alliage de brasure a une composition d'alliage comprenant, en % en masse, de 2,0 à 3,6 % d'Ag, de 0,6 à 0,9 % de Cu, de 1,0 à 5,0 % de In, de 3,0 à 5,0 % de Sb, de 0,0010 à 0,0300 % de Fe, et de 0,0010 à 0,0500 % de Co, le reste étant du Sn. De préférence, la composition d'alliage contient en outre, en % en masse, au moins l'un parmi Zr, Ge, Ga, P, As, Pb, Zn, Mg, Cr, Ti, Mo, Pt, Pd, Au, Al et Si en une quantité totale inférieure ou égale à 0,100 %.
PCT/JP2025/003328 2024-02-04 2025-02-03 Alliage de soudure, pâte à braser, bille de soudure, préforme de soudure, joint de soudure, circuit électronique embarqué, circuit électronique d'ecu, dispositif de circuit électronique embarqué et dispositif de circuit électronique d'ecu Pending WO2025164804A1 (fr)

Applications Claiming Priority (2)

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JP2024015315A JP7578897B1 (ja) 2024-02-04 2024-02-04 はんだ合金、はんだペースト、はんだボール、はんだプリフォーム、はんだ継手、車載電子回路、ｅｃｕ電子回路、車載電子回路装置、およびｅｃｕ電子回路装置
JP2024-015315 2024-02-04

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WO2025164804A1 true WO2025164804A1 (fr) 2025-08-07

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013252548A (ja) * 2012-06-08 2013-12-19 Nihon Almit Co Ltd 微細部品接合用のソルダペースト
WO2018164171A1 (fr) * 2017-03-10 2018-09-13 株式会社タムラ製作所 Alliage de soudage sans plomb, pâte à souder, et carte de circuit électronique
JP2019063830A (ja) * 2017-10-03 2019-04-25 株式会社弘輝 はんだ合金、はんだ接合材料及び電子回路基板
WO2020031361A1 (fr) * 2018-08-09 2020-02-13 株式会社タムラ製作所 Alliage de brasage sans plomb, pâte de brasage, substrat monté sur des circuits électroniques, et dispositif de commande électronique
JP7376842B1 (ja) * 2023-02-21 2023-11-09 千住金属工業株式会社 はんだ合金、はんだボール、はんだペースト及びはんだ継手

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013252548A (ja) * 2012-06-08 2013-12-19 Nihon Almit Co Ltd 微細部品接合用のソルダペースト
WO2018164171A1 (fr) * 2017-03-10 2018-09-13 株式会社タムラ製作所 Alliage de soudage sans plomb, pâte à souder, et carte de circuit électronique
JP2019063830A (ja) * 2017-10-03 2019-04-25 株式会社弘輝 はんだ合金、はんだ接合材料及び電子回路基板
WO2020031361A1 (fr) * 2018-08-09 2020-02-13 株式会社タムラ製作所 Alliage de brasage sans plomb, pâte de brasage, substrat monté sur des circuits électroniques, et dispositif de commande électronique
JP7376842B1 (ja) * 2023-02-21 2023-11-09 千住金属工業株式会社 はんだ合金、はんだボール、はんだペースト及びはんだ継手

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