Solder alloy, solder ball, solder pre-form, solder paste and solder joint

Description

1 / 27 “SOLDER ALLOY, SOLDER BALL, SOLDER PREFORM, SOLDER PASTE AND SOLDER JOINT” DIVIDED FROM BR 11 2024 006276-7, DEPOSITED ON 09 / 29 / 2022 Technical Field

[001] The present invention relates to a solder alloy, a solder ball, a solder preform, a solder paste and a solder joint for use in various electronic equipment. Background of the Invention

[002] In recent years, the performance of electronic components mounted on substrates has improved dramatically due to the increased functionality of commercial off-the-shelf electronic equipment, such as personal computers. The higher the performance of the electronic equipment, the greater the current supplied to the electronic components, and therefore, the solder joints used on a commercial electronic equipment substrate are exposed to high temperatures in some cases. When soldering is performed by staggered soldering, a solder joint is also exposed to a high temperature of approximately 150 °C. On the other hand, it is easy to assume that commercial electronic equipment is used in cold climate regions.

[003] Examples of solder joint uses where the solder joints are exposed to a hostile environment include, in addition to use for off-the-shelf commercial electronic equipment, use for vehicle-mounted electronic equipment or industrial electronic equipment. With regard to vehicles, automotive electronics has advanced and the transition from gasoline vehicles to electric and hybrid vehicles is underway. Accordingly, due to the expansion of use, a vehicle-mounted electronic equipment substrate may be placed in a location exposed to high temperatures, such as an engine room. On the other hand, when the Petition 870260039025, dated 04 / 27 / 2026, page 13 / 78 2 / 27 motor for, the welded joints can be exposed to temperatures as low as -40 °C in cold climate regions. Furthermore, depending on the operating environment, an external physical force, such as an impact, may be applied to the electronic equipment.

[004] Industrial electronic equipment is used in a location where it is difficult for a worker to perform a job. Therefore, as in the case of a vehicle-mounted electronic equipment substrate, it is assumed that an industrial electronic equipment substrate is exposed to an environment with extreme temperature changes or that an external force is applied to the electronic equipment.

[005] Moreover, as an alloy for connecting substrates and electronic components, an Sn-3Ag-0.5Cu solder alloy is widely used. The application range of solder alloys is expanding and, accordingly, as represented by their use in vehicle-mounted equipment, etc., solder alloys are increasingly required to have high connection reliability, so as not to cause rupture or deterioration of solder joints even in prolonged use in a harsh environment.

[006] However, when an electronic circuit is exposed to extreme temperature changes as described above, due to a difference in the coefficient of thermal expansion between the electronic components and a printed circuit board, the stress concentrates at the solder joints. Furthermore, when an external force is applied to the electronic equipment, the stress concentrates at the solder joints with small cross-sectional areas. Therefore, the use of conventional Sn-3Ag-0.5Cu solder alloy involves the risk of solder joint rupture, making a solder alloy that avoids this necessary.

[007] For example, in Patent Document 1, as a solder alloy that prevents the growth of a weld joint crack and suppresses the generation of voids in a thermal cycling environment, a composition Petition 870260039025, dated 04 / 27 / 2026, page 14 / 78 3 / 27 of an alloy potentially containing In and Co, etc., as optional elements in a Sn-Ag-Cu-Sb-Bi-Ni solder alloy is revealed.

[008] In Patent Document 2, a solder alloy that forms a fine structure of an intermetallic compound and has high crack resistance and high durability by preventing voids and leaching of Cu and preventing crack growth after a thermal cycle, an alloy composition that may contain Sb and In etc., as optional elements in a Sn-Ag-Cu-Bi-Ni-Co based solder alloy is disclosed.

[009] In Patent Document 3, as a solder alloy with excellent wettability and improved bond durability after a thermal cycle, an alloy composition that may contain Co etc., as optional elements in a Sn-Ag-Cu-Bi-Sb-In-Ni based solder alloy is disclosed. List of Citations Patent Documents

[010] Patent Document 1: Publication of Unexamined Japanese Patent Application No. 2017-170464.

[011] Patent Document 2: Publication of Unexamined Japanese Patent Application No. 2014-037005.

[012] Patent Document 3: Japanese Patent Publication No. 6060199. Brief Description of the Invention Technical problem

[013] However, the solder alloys described in Patent Documents 1 to 3 are designed focusing primarily on the thermal cycling properties as described above. When electronic equipment is exposed to thermal cycling, due to a difference in the coefficient of thermal expansion between a substrate and the electronic components, stress is applied to the solder joints. On the other hand, when vibration is applied to a circuit Petition 870260039025, dated 04 / 27 / 2026, page 15 / 78 4 / 27 electronic components mounted in a vehicle, the way voltage is applied is considered different from the voltage caused by the expansion and contraction of the printed circuit board and electronic components that occurs in a thermal cycle. Therefore, even when various voltages are applied to the solder joints due to the deterioration of the operating environment caused by the high functionality and expansion of the use of electronic equipment in recent years, in order to avoid solder joint failure, the strength of the solder alloy itself needs to be improved.

[014] Furthermore, examples of weld joint failure include, in addition to the failure of a weld alloy that constitutes the weld joint, failure at a joint interface caused by deterioration of the wettability of the weld alloy. Thus, to form a weld joint with greater reliability than conventional weld joints, it is necessary to reconsider publicly known alloy compositions.

[015] One objective of the present invention is to provide a solder alloy, a solder ball, a solder preform, a solder paste and a solder joint, which have excellent wettability and high reliability by preventing rupture of solder joints. Solution to the Problem

[016] The inventors examined in detail the stress to be applied to a solder joint due to a difference in the coefficient of thermal expansion between a substrate and an electronic component, and focused on the fact that the stress to be applied to a solder joint was close to the stress applied at the time of design in a physical test. When there is a large difference in the coefficient of thermal expansion, one of the substrates and the electronic component deform strongly, so that a portion of a solder alloy that constitutes a solder joint is stretched. When the drawability is excellent, the solder joint is prevented from breaking. Petition 870260039025, dated 04 / 27 / 2026, p. 16 / 78 5 / 27 even when a large voltage is applied to it.

[017] Furthermore, it is considered that, even when the stress caused by a difference in the coefficient of thermal expansion between a substrate and an electronic component is applied to a solder joint, provided that the strain energy of a solder alloy constituting the solder joint is optimal, the solder joint can be prevented from breaking. As illustrated in Figure 1, the strain energy in the present invention is represented by a region that follows an inflection point on a stress-strain curve to account for the strain energy. An area bounded by the vertical axis and the horizontal axis corresponds to the strain energy. As illustrated in Figure 1B, when the tensile stress and the amount of strain are large, this indicates that the strain energy is large. Thus, to increase the strain energy, high tensile strength and a large amount of strain are required.

[018] A possible cause of a solder joint rupture is a rupture at the joint interface between an electrode and a solder alloy. To avoid this rupture, the solder alloy needs to be improved in terms of wettability. The melting point of a solder alloy changes with the alloy composition, and to wet and spread the solder alloy when the melting point is high, the soldering temperature needs to be increased. However, from the point of view of heat resistance, etc., of an electronic component to be mounted on a substrate, it is not easy to change a defined temperature of the soldering equipment. Therefore, to improve the wettability of the solder alloy, the melting point of the solder alloy must be reduced.

[019] Formability, strain energy, and wettability are not considered in the conventional Sn-Ag-Cu-Sb-In-Ni-Bi solder alloys disclosed in Patent Documents 1 to 3, which have been conventionally studied focusing on thermal cycling resistance. In the alloy Petition 870260039025, dated 04 / 27 / 2026, p. 17 / 78 The solder alloy disclosed in Example 23 in Patent Document 1, consisting of Ag: 3.0% by mass, Cu: 0.7% by mass, Bi: 3.2% by mass, In: 3.0% by mass, Sb: 3.0% by mass, Ni: 0.03% by mass, Co: 0.008% by mass, with the remainder being Sn, was found to have a high liquidus line temperature and low wettability. The solder alloy disclosed in Example 40 in Patent Document 2, consisting of Ag: 3.0% by mass, Cu: 0.5% by mass, Sb: 1.5% by mass, In: 4.3% by mass, Ni: 0.05% by mass, Bi: 0.5% by mass, Co: 0.005% by mass, with the remainder being Sn, was found to have low formability. In the solder alloy disclosed in Example 54 in Patent Document 3, consisting of Ag: 0.1% by mass, Cu: 0.7% by mass, Sb: 0.08% by mass, In: 2% by mass, Ni: 0.065% by mass, Bi: 4.5% by mass, Co: 0.003% by mass, with the remainder being Sn, the solder alloy was found to have a coarse alloy structure.

[020] Therefore, the inventors seriously studied an alloy composition that achieved an overall improvement in wettability, an improvement in strain energy, and high formability and high tensile strength at the same time, even in a conventional solder alloy considered to have excellent thermal cycle resistance. As a result, the inventors discovered that, in an Sn-Ag-Cu-Sb-In-Ni-Bi solder alloy, when it had a predetermined Bi content, the reduction of In and Sb contents caused the crystallization of fine InSb and contributed to an improvement in formability. Since it was discovered that Bi dissolved in Sn, a Bi content within a predetermined range contributed to an improvement in tensile strength. Furthermore, it was found that Ag and Ni contributed to the refinement of the alloy structure. It is presumed that Ag promotes the densification of the alloy structure, since Ag forms a fine Ag3Sn network.Furthermore, it was found that Ni contributed to the refinement of the alloy structure at the joint interface. Additionally, it was found that Cu suppressed an increase in... Petition 870260039025, dated 04 / 27 / 2026, p. 18 / 78 7 / 27 liquidus line temperature in a range where Ag, Ni, Bi, In, and Sb satisfied the properties described above. As described, based on the finding that the effects described above could only be exerted when the contents of the respective constituent elements were within predetermined ranges, the present invention was completed.

[021] The present invention obtained from these discoveries is as follows: (1) A solder alloy having an alloy composition consisting of, in % by mass: Ag: 1.0 to 3.8%; Cu: 0.4 to 0.8%; Sb: 0.03 to 2.90%; In: 1.1 to 4.2%; Ni: 0.01 to 0.14%; Bi: 0.1 to 5.0%, with the remainder being Sn; (2) The solder alloy according to (1) above, further comprising, in % by mass, Co: 0.1% or less; (3) The solder alloy according to (1) or (2) above, further comprising, in % by mass, at least one of Zr, Fe, Ge, Ga, P, As, Pb, Zn, Mg, Cr, Ti, Mn, Mo, Pt, Pd, Au, Al and Si: 0.1% or less in total; (4) The solder alloy according to any one of (1) to (3) above, satisfying at least one of the following relations (1) to (4): 113 < Sn / Cu < 165 Ratio (1); 0.06 < AgxNi < 0.19 Ratio (2); 0.10 < Bi / (In+Sb) < 0.32 Relationship (3); 0.432 < (In+Sb) / (Ag+In+Bi) < 0.999 Ratio (4); where Sn, Cu, Ag, Ni, Bi, In and Sb in the ratios (1) to (4) above each represent the content (% by mass) of the same in the composition of Petition 870260039025, dated 04 / 27 / 2026, page 19 / 78 8 / 27 league; (5) A solder ball consisting of solder alloy according to any one of (1) to (4) above; (6) A weld preform consisting of the weld alloy according to any one of (1) to (4) above; (7) A solder paste comprising a solder powder consisting of the solder alloy according to any one of (1) to (4) above; (8) A weld joint comprising the weld alloy according to any one of (1) to (4) above. Brief Description of the Figures

[022] Figure 1A is a diagram that illustrates a stress-strain curve to describe strain energy, Figure 1A is a diagram that describes that an area bounded by an axis representing tensile strength and an axis representing strain is small.

[023] Figure 1B is a diagram that illustrates a stress-strain curve to describe strain energy, Figure 1B is a diagram describing that an area bounded by the axis representing tensile strength and the axis representing strain is large.

[024] Figure 2A is a SEM sectional photograph of a solder joint, Figure 2A illustrates Example 3.

[025] Figure 2B is a SEM sectional photograph of a solder joint, Figure 2B illustrates Comparative Example 3.

[026] Figure 3A is a SEM sectional photograph of a solder joint, Figure 3A illustrates Example 3.

[027] Figure 3B is a SEM sectional photograph of a solder alloy, Figure 3B illustrates Comparative Example 13. Description of Implementation Methods

[028] The present invention is described in more detail below. In Petition 870260039025, dated 04 / 27 / 2026, p. 20 / 78 9 / 27 In this description, “%” relating to solder alloy composition refers to “% by mass”, unless otherwise specified. 1. Welding Alloy (1) Ag: 1.0 to 3.8%

[029] Ag forms a fine Ag3Sn network and can promote the densification of the solder alloy. When the Ag content is less than 1.0%, Ag3Sn cannot be crystallized and formability deteriorates. Furthermore, an Ag3Sn network cannot be formed. A lower limit for the Ag content is 1.0% or more, preferably 1.5% or more, more preferably 2.0% or more, still preferably 2.5% or more, and particularly preferably 3.0% or more. On the other hand, when the Ag content is greater than 3.8%, coarse Ag3Sn crystallizes and, consequently, the alloy structure does not become dense and formability deteriorates. An upper limit for the Ag content is 3.8% or less, and preferably 3.4% or less. (2) Cu: 0.4 to 0.8%

[030] Cu can maintain excellent wettability of the molten solder by suppressing an increase in the liquidus line temperature. When the Cu content is less than 0.4% or greater than 0.8%, the liquidus line temperature increases, fluidity at a joining temperature deteriorates, and wettability deteriorates. A lower limit for the Cu content is 0.4% or more, preferably 0.5% or more, and even more preferably 0.6% or more. An upper limit for the Cu content is 0.8% or less, and preferably 0.7% or less. (3) Sb: 0.03 to 2.90%

[031] Sb causes crystallization of fine InSb when added simultaneously with In and can improve stampability. When the Sb content is less than 0.03%, InSb does not crystallize and the stampability-improving effect cannot be obtained. A lower limit for the Sb content is 0.03% or more, and preferably 0.05% or more. On the other hand, when the content Petition 870260039025, dated 04 / 27 / 2026, p. 21 / 78 If the Sb content is greater than 2.90%, the liquidus line temperature increases and wettability deteriorates. An upper limit for Sb content is 2.90% or less, preferably 2.50% or less, and most preferably 2.00% or less. (4) In: 1.1 to 4.2%

[032] Causes the crystallization of fine InSb when added simultaneously with Sb, and can improve stampability. When the In content is less than 1.1%, InSb does not crystallize and the stampability-improving effect cannot be obtained. A lower limit for the In content is 1.1% or more, preferably 2.0% or more, and more preferably 3.0% or more. On the other hand, when the In content is greater than 4.2%, a coarse InSb compound crystallizes due to simultaneous addition with Ag and, consequently, stampability deteriorates. An upper limit for the In content is 4.2% or less, and preferably 4.0% or less. (5) Ni: 0.01 to 0.14%

[033] Ni blocks the diffusion of Cu to Sn after welding and suppresses the growth of an intermetallic compound that precipitates at the joint interface. Furthermore, by suppressing the thickening of the intermetallic compound that precipitates at the joint interface, Ni can strengthen the joint interface. When the Ni content is less than 0.01%, the alloy structure does not become sufficiently dense and the strain energy does not improve. In addition, the joint interface cannot be strengthened. A lower limit for Ni content is 0.01% or more, preferably 0.02% or more, more preferably 0.03% or more, and even more preferably 0.04% or more. On the other hand, when the Ni content is greater than 0.14%, due to an increase in the liquidus line temperature, wettability deteriorates. An upper limit for the Ni content is 0.09% or less, preferably 0.06% or less, and more preferably 0.05% or less. Petition 870260039025, dated 04 / 27 / 2026, p. 22 / 78 11 / 27 (6) Bi: 0.1 A 5.0%

[034] Bi dissolves in Sn and can, consequently, improve tensile strength. When the Bi content is less than 0.1%, tensile strength does not improve. A lower limit for Bi content is 0.1% or more, and preferably 0.5% or more. On the other hand, when the Bi content is greater than 5.0%, due to Bi segregation, the weld alloy weakens and deteriorates tensile strength and formability. An upper limit for Bi content is 5.0% or less, preferably 4.0% or less, more preferably 3.0% or less, still preferably 2.0% or less, and particularly preferably 1.0% or less. (7) Remaining: Sn

[035] The remainder of the solder alloy according to the present invention is Sn. In addition to the elements described above, unavoidable impurities may be contained. Even when unavoidable impurities are present, they do not affect the effects described above. (8) Co: 0.100% or less

[036] Co is an optional element that has the effects of suppressing intermetallic compound growth and refining the alloy structure. An upper limit of the Co content is preferably 0.100% or less, more preferably 0.050% or less, and even more preferably 0.010% or less. Although a lower limit of the Co content is not particularly restrictive, from the point of view of refining the alloy structure, the lower limit is preferably 0.001% or more, more preferably 0.003% or more, even more preferably 0.005% or more, even more preferably 0.006% or more, particularly preferably 0.007% or more, and even more preferably 0.008% or more. (9) Other Optional Elements

[037] In addition to the elements described above, the solder alloy of Petition 870260039025, dated 04 / 27 / 2026, page 23 / 78 12 / 27 according to the present invention may contain at least one of Zr, Fe, Ge, Ga, P, As, Pb, Zn, Mg, Cr, Ti, Mn, Mo, Pt, Pd, Au, Al and Si: 0.1% or less in total. In particular, with regard to Fe, it has the effect of suppressing the growth of an intermetallic compound that precipitates at a joint interface, so that by containing Fe in the solder alloy of the present invention, the effects of Ni can be further enhanced. Even when a content of these elements is 0.1% or less, a coarse compound does not precipitate and the effects of the present invention described above can be exerted. A total content of these elements is preferably 0.1% or less, more preferably 0.09% or less, still preferably 0.05% or less, and particularly preferably 0.015% or less. The content of each element is preferably from 0.0003 to 0.02%, although not particularly limited.Among these, like Ni, Fe blocks the diffusion of Cu to Sn after welding and suppresses the growth of an intermetallic compound that precipitates at the joint interface. Furthermore, by suppressing the thickening of the intermetallic compound that precipitates at the joint interface, Fe can strengthen the joint interface. (10) Relationships (1) to (4) 113 < Sn / Cu < 165 Relationship (1), 0.06 < AgxNi < 0.19 Relationship (2), 0.10 < Bi / (In+Sb) < 0.32 Relationship (3), 0.432 < (In+Sb) / (Ag+In+Bi) < 0.999 Relationship (4).

[038] Sn, Cu, Ag, Ni, Bi, In and Sb in the ratios (1) to (4) above represent, each, their content (% by mass) in the alloy composition.

[039] It is preferable that the solder alloy according to the present invention satisfies at least one of the relationships (1) to (4). An alloy composition that satisfies all these relationships can exert particularly good effects. Petition 870260039025, dated 04 / 27 / 2026, p. 24 / 78 13 / 27 excellent.

[040] Cu contributes greatly to the liquidus line temperature. Therefore, when its ratio with Sn as the main constituent satisfies relation (1), a liquidus line temperature is obtained that exhibits adequate wettability for soldering. A lower limit of relation (1) is preferably 113 or more, more preferably 123 or more, and particularly preferably 125 or more. An upper limit of relation (1) is preferably 165 or less, more preferably 151 or less, and also preferably 132 or less.

[041] In the solder alloy according to the present invention, Ag contributes to the densification of the alloy structure, and Ni contributes to the homogeneous densification of a joint interface. Both elements can crystallize a compound with Sn, and when their respective contents are well balanced, the thickening of the compound is suppressed and the densification of the alloy structure is promoted. A lower limit of the ratio (2) is preferably 0.06 or more, more preferably 0.09 or more, and even more preferably 0.10 or more. An upper limit of the ratio (2) is preferably 0.19 or less, and more preferably 0.15 or less.

[042] Bi, In, and Sb contribute to the mechanical properties of the solder alloy according to the present invention. Bi contributes to an improvement in tensile strength, and In and Sb contribute to an improvement in formability. When the content of any of the elements is excessive or insufficient, as described above, both tensile strength and formability may not be guaranteed. Therefore, it is preferable that the solder alloy according to the present invention satisfies ratio (3). A lower limit of ratio (3) is preferably 0.10 or more, more preferably 0.14 or more, and even more preferably 0.16 or more. An upper limit of ratio (3) is preferably 0.32 or less, more Petition 870260039025, dated 04 / 27 / 2026, p. 25 / 78 14 / 27 preferably 0.25 or less, and even more preferably 0.200 or less.

[043] The solder alloy according to the present invention can be further improved in formability by satisfying relation (4). To this end, in order to maintain a balance between the total contents of In and Sb which improve formability when added, and the total contents of Ag, In and Bi which deteriorate formability when their contents are high, these elements are preferably contained. A lower limit of relation (4) is preferably 0.432 or more, more preferably 0.433 or more, and more preferably 0.442 or more. An upper limit of relation (4) is preferably 0.999 or less, more preferably 0.769 or less, and more preferably 0.750 or less. 2. Welding Sphere

[044] The solder alloy according to the present invention can be used as a solder ball. A solder ball according to the present invention is used to form electrode protrusions and a substrate of a semiconductor package such as a BGA (Ball Grid Array). The diameter of the solder ball according to the present invention is preferably within a range of 1 to 1000 µm. The solder ball can be produced by a general solder ball production method. 3. Welding Preform

[045] One form of a solder preform according to the present invention is not particularly limited and can be used in the form of a plate, a ring shape, a cylindrical shape, a ribbon shape, a square shape, a disc shape, a washer shape, a chip shape and a wire shape etc. The solder preform may contain internally high melting point metal grains (for example, Ni grains and Cu grains, and an alloy powder containing mainly Ni and Cu) which have a melting point Petition 870260039025, dated 04 / 27 / 2026, page 26 / 78 15 / 27 higher than that of the solder alloy and are easily moistened with molten solder. 4. Solder Paste

[046] The solder alloy according to the present invention can be used as solder paste. The solder paste is obtained by mixing a solder alloy powder with a small amount of flux and processing them into a paste. The solder alloy according to the present invention can be used as solder paste for mounting an electronic component on a printed circuit board by a reflow soldering method. The flux to be used for the solder paste can be a water-soluble flux or a water-insoluble flux. Typically, a rosin-based flux is used as a water-insoluble rosin-based flux. 5. Welding Joint

[047] The solder joint according to the present invention connects an IC chip and a (interposed) substrate of the IC chip in a semiconductor package, or joins and connects a semiconductor package and a printed circuit board. That is, the solder joint according to the present invention is a connecting portion of an electrode and can be formed using general soldering conditions.

[048] The joining method using the solder alloy according to the present invention can be carried out in the usual manner using, for example, a reflow method. A heating temperature can be adjusted as appropriate according to the heat resistance of a chip and a liquid line temperature of the solder alloy. Other joining conditions can be adjusted as appropriate according to the solder alloy composition. Examples

[049] Solder alloys consisting of the alloy compositions described in Tables 1 to 3 were prepared, and the liquidus line temperature was measured as evaluation 1, the density of the solder structure was evaluated Petition 870260039025, dated 04 / 27 / 2026, page 27 / 78 16 / 27 as evaluation 2, stampability was evaluated as evaluation 3, tensile strength was evaluated as evaluation 4, and homogeneous refinement of a joint interface was evaluated as evaluation 5. - Evaluation 1: Liquidus Line Temperature

[050] The respective solder alloys described in Tables 1 to 3 were produced and their liquidus line temperatures were measured. The liquidus line temperatures were measured by a DSC method similar to the JIS Z 3198-1 solidus temperature measurement method. A case where the liquidus line temperature was 200 to 218 °C was rated as “excellent”, a case where the liquidus line temperature was greater than 218 °C and 220 °C or less was rated as “good”, a case where the liquidus line temperature was greater than 220 °C was rated as “poor”, and a case where the liquidus line temperature was less than 200 °C was also rated as “poor”. - Assessment 2: Weld Structure Density

[051] The solder alloys with the alloy compositions described in Tables 1 to 3 were cast in a predetermined mold, and the resulting solder alloys were resin-molded and ground. The portions where the solder alloys were ground by approximately half were photographed at 1000x magnification using a FE-SEM. From the photograph taken, the density of Ag3Sn and the refinement of InSb were evaluated by cross-sectional observation and compositional mapping analysis using EDS. Each compound was identified by compositional mapping analysis, and a larger crystalline grain was visually selected. For this crystal grain, two parallel tangent lines were drawn so that the distance between them became greater, and this distance was defined as the maximum crystal grain size. A case where the maximum crystalline grain size of Ag3Sn was 5 pm or more and 10 pm or less was evaluated as “excellent,” a case where Petition 870260039025, dated 04 / 27 / 2026, page 28 / 78 17 / 27 where the maximum crystalline grain size was greater than 10 pm and 15 pm or less was rated as “good”, and one case where the maximum crystal grain size was less than 5 pm and one case where the maximum crystal grain size was greater than 15 pm were rated as “poor”. One case where the maximum crystalline grain size of InSb was 5 pm or less was rated as “excellent”, one case where the maximum crystalline grain size was greater than 5 pm and 10 pm or less was rated as “good”, and one case where the maximum crystal grain size was greater than 10 pm was rated as “poor”. In evaluation 2, a case in which AgaSn and InSb were evaluated as "excellent" was evaluated as "excellent," a case in which one of them was evaluated as "excellent" and the other as "good" was evaluated as "good," and a case in which either of them was evaluated as "poor" was evaluated as "poor." - Rating 3, 4: Formability, Tensile Strength

[052] Formability and tensile strength were measured according to JIS Z 3198-2. Each weld alloy described in Tables 1 to 3 was cast in a mold and a test piece with a standard length of 30 mm and a diameter of 8 mm was manufactured. The manufactured test piece was stretched at a rate of 6 mm / min at room temperature using a Type 5966 die manufactured by Instron, and the strength at which the test piece broke was measured. Formability was measured from a ratio of a cross-sectional area S1 of a broken portion of the test piece to a cross-sectional area S0 before the test. A case where the tensile strength was 65 MPa or more was rated as “excellent”, a case where the tensile strength was 60 MPa or more and less than 65 MPa was rated as “good”, and a case where the tensile strength was less than or greater than 60 MPa was rated as “poor”.A case where the printability was 50% or more was rated as "good," and a case where the printability was less than 50% was rated as "poor."

[053] The evaluation results are presented in Tables 1 Petition 870260039025, dated 04 / 27 / 2026, page 29 / 78 18 / 27 to 3. Evaluation 5: Homogeneous Refinement of the Joint Interface

[054] A 0.6 mm solder ball was prepared from each solder alloy described in Tables 1 to 3. After this solder ball was mounted on a Cu pad, reflow soldering was performed at 245 °C, and consequently, a solder collision was formed. By measuring the thickness of an intermetallic compound (IMC) from a sectional SEM photograph, imagining a section of a joint interface between the solder collision and the Cu pad, the homogeneous refinement of the joint interface was evaluated. When the joint interface is homogeneously refined, the intermetallic compound layer becomes thin, so in evaluation 5, the homogeneous refinement was evaluated based on the thickness of the intermetallic compound. The sectional SEM photograph was analyzed by image analysis software (Scandium manufactured by SEIKA CORPORATION), and a thickness of the intermetallic compound layer was measured.A case in which the thickness of the intermetallic compound was 1.5 pm or less was rated as "excellent," a case in which the thickness was greater than 1.5 pm and 2.5 pm or less was rated as "good," and a case in which the thickness was greater than 2.5 pm was rated as "poor."

[055] The evaluation results are presented in Tables 1 to 3. Table 1 Sn Ag Cu Sb In Ni Bi Co Others Ratio(1) Sn / Cu Ratio(2 AgxNi Ratio(3 Bi / (In+Sb)) Ratio(4) (In+Sb) / (Ag+In+Bi) Ex.1 Remainder 1.0 0.7 2.0 0 3.0 0.0 5 1.0 132 0.05 0.20 1.000 Ex.2 Remainder 2.0 0.7 2.0 0 3.0 0.0 5 1.0 130 0.10 0.20 0.833 Ex.3 Remainder 3.0 0.7 2.0 0 3.0 0.0 5 1.0 129 0.15 0.20 0.714 Petition 870260039025, dated 04 / 27 / 2026, p. 30 / 78 19 / 27 Sn Ag Cu Sb In Ni Bi Co Others Ratio(1) Sn / Cu Ratio(2 AgxNi Ratio(3 Bi / (In+Sb)) Ratio(4) (In+Sb) / (Ag+In+Bi) Ex.4 Remainder 3.8 0.7 2.0 0 3.0 0.0 5 1.0 128 0.19 0.20 0.641 Ex.5 Remainder 3.0 0.4 2.0 0 3.0 0.0 5 1.0 226 0.15 0.20 0.714 Ex.6 Remainder 3.0 0.5 2.0 0 3.0 0.0 5 1.0 181 0.15 0.20 0.714 Ex.7 Remainder 3.0 0.6 2.0 0 3.0 0.0 5 1.0 151 0.15 0.20 0.714 Ex.8 Remainder 3.0 0.8 2.0 0 3.0 0.0 5 1.0 113 0.15 0.20 0.714 Ex.9 Remainder 3.0 0.7 0.0 3 3.0 0.0 5 1.0 132 0.15 0.33 0.433 Ex.1 0 Remainder 3.0 0.7 0.0 5 3.0 0.0 5 1.0 132 0.15 0.33 0.436 Ex.1 1 Remainder 3.0 0.7 0.5 0 3.0 0.0 5 0.5 132 0.15 0.14 0.538 Ex.1 2 Remainder 3.0 0.7 1.0 0 3.0 0.0 5 1.0 130 0.15 0.25 0.571 Ex.1 3 Remainder 3.0 0.7 2.9 0 3.0 0.0 5 1.0 128 0.15 0.17 0.843 Ex.1 4 Remainder 3.0 0.7 2.0 0 1.1 0.0 5 1.0 132 0.15 0.32 0.608 Ex.1 5 Remainder 3.0 0.7 2.0 0 2.0 0.0 5 1.0 130 0.15 0.25 0.667 Ex.1 6 Remainder 3, 0 0, 7 2.0 0 4, 0 0.0 5 1.0 128 0.15 0.17 0.750 Ex.1 7 Remainder 3.0 0.7 2.0 0 4.2 0.0 5 1.0 127 0.15 0.16 0.756 Ex.1 8 Remainder 3.0 0.7 2.0 0 3.0 0.0 1 1.0 129 0.03 0.20 0.714 Ex.1 9 Remainder 3, 0 0, 7 2,0 0 3, 0 0,0 2 1,0 129 0,06 0,20 0,714 Ex.2 1 Remainder 3, 0 0, 7 2.0 0 3.0 0.0 4 1.0 129 0.12 0.20 0.714 Ex.2 2 Remainder 3.0 0.7 2.0 0 3.0 0.0 6 1.0 129 0.18 0.20 0.714 Ex.2 3 Remainder 3.0 0, 7 2.0 0 3.0 0.0 5 0.1 130 0.15 0.02 0.820 Ex.2 4 Remainder 3.0 0.7 2.0 0 3.0 0.0 5 0.5 130 0.15 0.10 0.769 Ex.2 5 Remainder 3.0 0.7 2.0 0 3.0 0.0 5 2.0 128 0.15 0.40 0.625 Ex.2 6 Remainder 3, 0 0, 7 2.0 0 3, 0 0.0 5 3.0 126 0.15 0.60 0.556. Petition 870260039025, dated 04 / 27 / 2026, page 31 / 78 20 / 27 Sn Ag Cu Sb In Ni Bi Co Others Ratio(1) Sn / Cu Ratio(2 AgxNi Ratio(3 Bi / (In+Sb ) Ratio(4) (In+Sb) / (Ag+ In+Bi) Ex.2 7 Remainder 3, 0 0, 7 2,0 0 3, 0 0,0 5 4,0 125 0,15 0,80 0,500 Table 1 - continued Evaluation 1: Liquidus line temperature Evaluation 2: Weld structure density Evaluation 3: Formability Evaluation 4: Tensile strength Evaluation 5: Homogeneous refinement of the joint interface Comprehensive evaluation Ex.1 excellent good good excellent good good Ex.2 excellent excellent good excellent excellent good Ex.3 excellent excellent good excellent excellent good Ex.4 excellent excellent good excellent excellent good Ex.5 good excellent good excellent excellent good Ex.6 good excellent good excellent excellent good Ex.7 excellent excellent good excellent excellent good Ex.8 excellent excellent good excellent excellent good Ex.9 excellent excellent good good excellent good Ex.10 excellent excellent good good excellent good Ex.11 excellent excellent good excellent excellent good Ex.12 excellent excellent good excellent excellent good Ex.13 excellent excellent good excellent excellent good Ex.14 excellent excellent good excellent excellent good Ex.15 excellent excellent good excellent excellent good Ex.16 excellent excellent good excellent excellent good Ex.17 excellent excellent good excellent excellent good Ex.18 excellent good good good good good Ex.19 excellent excellent good excellent excellent good Ex.20 excellent excellent good excellent excellent good Ex.21 excellent excellent good excellent excellent good Ex.22 excellent excellent good excellent excellent good Ex.23 excellent excellent good good excellent good Ex.24 excellent excellent good excellent excellent good Ex.25 excellent excellent good good excellent good Ex.26 excellent excellent good good excellent good Ex.27 excellent excellent good good excellent good. Petition 870260039025, dated 04 / 27 / 2026, page 32 / 78 21 / 27 Table 2 Sn Ag Cu Sb In Ni Bi Co Others Ratio( ) Sn / Cu Ratio(: ) AgxNi Ratio( Bi / (In+S b) Ratio(4) (In+Sb) / (Ag+In+ Bi) Ex.2 8 Rest o 3, 0 0, 7 2,0 0 3, 0 0,0 5 5, 0 123 0,15 1,00 0,455 Ex.2 9 Rest o 3, 0 0, 7 2,0 0 3, 0 0,0 5 1, 0 0,01 0 129 0,15 0,20 0,714 Ex.3 0 Rest o 3, 0 0, 7 2,0 0 3, 0 0,0 5 1, 0 0,10 0 129 0,15 0.20 0.714 Ex.3 1 Remainder 3, 4 0.7 0.0 5 3.0 0.0 3 0.5 0.01 0 132 0.10 0.16 0.442 Ex.3 2 Remainder 3.0 0.7 2.0 0 4.0 0.0 5 1.0 0.00 1 Fe:0.01 5 127 0.15 0.17 0.750 Ex.3 3 Rest 3.0 0.7 2.0 0 4, 0 0.0 5 1, 0 0.01 0 Fe:0.01 0 127 0.15 0.17 0.750 Ex.3 5 Rest 3, 0 0. 7 2.0 0 4, 0 0.0 5 1, 0 0.01 0 Fe:0.01 5 127 0.15 0.17 0.750 Ex.3 6 Remainder 3, 0 0, 7 2.0 0 4, 0 0.0 5 1, 0 0.00 1 Fe:0.01 0 127 0.15 0.17 0.750 Ex.3 7 Remainder 3, 0 0, 7 2.0 0 4, 0 0.0 5 1.0 0.00 8 Fe:0.01 0 127 0.15 0.17 0.750 Ex.3 8 Rest 3, 0 0, 7 2.0 0 4, 0 0.0 5 1, 0 Zr:0.01 5 127 0.15 0.17 0.750 Ex.39 0.15 0.17 0.750 Ex.4 1 Remainder 3, 0 0, 7 2.0 0 4, 0 0.0 5 1, 0 Ga:0.0 15 127 0.15 0.17 0.750 Ex.4 2 Remainder 3, 0 0, 7 2.0 0 4, 0 0.0 5 1.0 P:0.015 127 0.15 0.17 0.750 Ex.4 3 Rest 3.0 0.7 2.0 0 4.0 0.0 5 1.0 As:0.01 5 127 0.15 0.17 0.750 Ex.4 4 Rest 3.0 0.7 2.0 0 4.0 .0 0 0.7 2.0 0 4, 0 0.0 5 1, 0 Mg:0.0 15 127 0.15 0.17 0.750 Ex.4 7 Rest 8 Remainder 3, 0 0, 7 2,0 0 4, 0 0,0 5 1, 0 Ti:0,01 5 127 0,15 0,17 0,750 Ex.4 9 Remainder 3, 0 0, 7 2,0 0 4, 0 0,0 5 1, 0 Mn:0,0 15 127 0.15 0.17 0.750 Ex.5 Rest 3, 0, 2.0 4, 0.0 1, Mo:0.0 127 0.15 0.17 0.750. Petition 870260039025, dated 04 / 27 / 2026, page 33 / 78 22 / 27 Sn Ag Cu Sb In Ni Bi Co Others Ratio( ) Sn / Cu Ratio(: ) AgxNi Ratio( Bi / (In+S b) Ratio(4) (In+Sb) / (Ag+In+ Bi) 0 o 0 7 0 0 5 0 15 Ex.5 1 Rest o 3, 0 0, 7 2,0 0 4, 0 0,0 5 1, 0 Pt:0,01 5 127 0,15 0,17 0,750 Ex.5 2 Rest o 3, 0 0, 7 2,0 0 4, 0 0,0 5 1, 0 Pd:0,01 5 127 0,15 0,17 0,750 Ex.5 3 Rest o 3, 0 0, 7 2,0 0 4, 0 0.0 5 1.0 Au:0.01 5 127 0.15 0.17 0.750 Ex.5 4 Rest 3.0 0.7 2.0 0 4.0 0.0 5 1.0 Al:0.01 5 127 0.15 0.17 0.750 Table 2 - continued Evaluation 1: Liquidus line temperature Evaluation 2: Weld structure density Evaluation 3: Formability Evaluation 4: Tensile strength Evaluation 5: Homogeneous refinement of the joint interface Comprehensive evaluation Ex.28 excellent excellent good good good excellent good Ex.29 excellent excellent good excellent excellent good Ex.30 excellent excellent good excellent excellent good Ex.31 excellent excellent good excellent excellent good Ex.32 excellent excellent good excellent excellent good Ex.33 excellent excellent good excellent excellent good Ex.34 excellent excellent good excellent excellent good Ex.35 excellent excellent good excellent excellent good Ex.36 excellent excellent good excellent excellent good Ex.37 excellent excellent good excellent excellent good Ex.38 excellent excellent good excellent excellent good Ex.39 excellent excellent good excellent excellent good Ex.40 excellent excellent good excellent excellent good Ex.41 excellent excellent good excellent excellent good Ex.42 excellent excellent good excellent excellent good Ex.43 excellent excellent good excellent excellent good Ex.44 excellent excellent good excellent excellent good Ex.45 excellent excellent good excellent excellent good Ex.46 excellent excellent good excellent excellent good Ex.47 excellent excellent good excellent excellent good Ex.48 excellent excellent good excellent excellent good Ex.49 excellent excellent good excellent excellent good Ex.50 excellent excellent good excellent excellent good Ex.51 excellent excellent good excellent excellent good Ex.52 excellent excellent good excellent excellent good Ex.53 excellent excellent good excellent excellent good Ex.54 excellent excellent good excellent excellent good. Petition 870260039025, dated 04 / 27 / 2026, page 34 / 78 23 / 27 Table 3 [Sn Ag Cu Sb In Ni Bi Co Others] [Relation]' ) Sn / Cu Relation] 2) AgxNi Relation] ) Bi / ]In+S b) Relation] ]In+Sb) / ]Ag+In+ Bi) Ex.55 Rest o 3, 0 0, 7 2,0 0 4, 0 0,05 1,0 Si:0,015 127 0,15 0,17 0,750 Ex.56 Rest o 3, 0 0, 7 2,0 0 4, 0 0,05 1,0 0,01 0 Zr:0,00 5, Fe:0,00 5, Ge:0,00 5, Ga:0,00 5, P:0,005 , As:0,00 5, Pb:0,00 5, Zn:0,00 5, Mg:0.00 5, Cr:0.00 5, Ti:0.005 , Mn:0.00 5, Mo:0.00 5, Pt:0.00 5, Pd:0.00 5, Au:0.00 5, Al:0.005 , Si:0.005 127 0.15 0.17 0.750 Ex. Comp.1 Rest 0, 1 0, 7 0.0 8 2, 0 0.07 4.5 0.00 3 132 0.01 2.16 0.315 Ex. Comp.2 Rest 0, 9 0. 7 2.0 0 3, 0 0.05 1.0 132 0.05 0.20 1,020 Ex. Comp.3 Rest 3 9 0, 7 2.0 0 3, 0 0.05 1.0 128 0.20 0.20 0.633 Ex. Comp.4 Rest 3, 0 0, 3 2.0 0 3, 0 0.05 1.0 302 0.15 0.20 0.714 Ex. Comp.5 Rest 3, 0 0, 3 3.0 0 2, 5 0.04 - 0.01 0 304 0.12 - 1.000 Ex. Rest 3, 0, 2.0 3, 0.05 1.0 100 0.15 0.20 0.714 Petition 870260039025, dated 04 / 27 / 2026, page 35 / 78 24 / 27 Sn Ag Cu Sb In Ni Bi Co Others relation f) Sn / Cu Relation^ 2) AgxNi Relation( ) Bi / (In+S b) Relation 4) (In+Sb) / (Ag+In+ Bi) Comp.6 o 0 9 0 0 Ex. Comp.7 Rest o 1, 2 0, 9 1,0 0 1, 0 - 2,5 104 - 1,25 0,426 Ex. Comp.8 Rest o 3, 0 0, 5 - 4, 0 0,05 1,5 0,00 5 182 0,15 0,38 0,471 Ex. Comp.9 Rest o 3, 0 0, 7 0,0 2 3, 0 0,05 1,0 132 0,15 0,33 0,431 Ex. Comp.10 Rest 3, 0 0, 7 30 0 3, 0 0.03 3.2 0.00 8 124 0.09 0.53 0.652 Ex. Comp.11 Rest 1, 0 0, 7 1.5 0 ^|oi 0.05 1.0 0.03 0 135 0.05 0.40 0.833 Comp. 1.0 129 0.02 0.20 0.714 Ex. Comp.14 Rest 3, 0 0, 5 1.0 0 4, 0 0.15 0.5 182 0.45 0.10 0.667 Ex. Comp.15 Rest 3, 4 0, 7 2.5 0 1, 1 0.07 - 132 0.24 - 0.800 Ex. Comp.16 Rest 3, 0 0, 7 2.0 0 3, 0 0.05 00 5 130 0.15 0.01 0.826 Ex. Comp.17 Rest 3, 0 0, 7 2.0 0 3, 0 0.05 55 123 0.15 1.10 0.435 Ex. Comp.18 Rest o 3.0 0.7 3.0 0 3.0 -60 120 -1.00 0.500 * The underlined text indicates that it does not fall within the scope of the present invention. Table 3 - continued Evaluation 1: Liquidus line temperature Evaluation 2: Weld structure density Evaluation 3: Formability Evaluation 4: Tensile strength Evaluation 5: Homogeneous joint interface refinement Comprehensive evaluation Ex.55 excellent excellent good excellent excellent good Ex.56 excellent excellent good excellent excellent good Ex. Comp.1 good poor poor good poor poor Ex. Comp.2 good poor poor good poor poor Ex. Comp.3 good poor poor good good poor Ex. Comp.4 poor good good good good poor Ex. Comp.5 poor good good poor good poor Petition 870260039025, dated 04 / 27 / 2026, page 36 / 78 25 / 27 Evaluation 1: Liquidus line temperature Evaluation 2: Weld structure density Evaluation 3: Formability Evaluation 4: Tensile strength Evaluation 5: Homogeneous joint interface refinement Comprehensive evaluation Ex. Comp.6 bad good good good good good bad Ex. Comp.7 bad good good good bad bad Ex. Comp.8 good good bad good good bad Ex. Comp.9 good good bad good good bad Ex. Comp.10 bad good good good good bad Ex. Comp.11 good good bad good bad bad Ex. Comp.12 good bad bad good good bad Ex. Comp.13 good good good good bad bad Ex. Comp.14 bad good good good good bad Ex. Comp.15 good good good bad good bad Ex. Comp.16 good good bad bad good bad Ex. Comp.17 good good bad bad good bad Ex. Comp.18 good good bad bad bad bad

[056] As is clear from Tables 1 to 3, it was found that the constituent elements of Examples 1 to 56 were all suitable and their temperatures on the liquidus line were within a predetermined range. Furthermore, the structures of the solder alloys were dense and exhibited excellent formability and tensile strength. In addition, the structures at the joint interfaces were homogeneous and fine. It was confirmed that Examples 2 to 4, 7, 8, 11 to 17, 19 to 22, 24 and 29 to 56 satisfying relations (1) to (4) obtained excellent results in all evaluation items.

[057] On the other hand, in Comparative Examples 1 to 3, due to an excessive or insufficient Ag content, the alloy structure did not become dense and exhibited low formability.

[058] In Comparative Examples 4 to 7, due to a content Petition 870260039025, dated 04 / 27 / 2026, page 37 / 78 26 / 27 excessive or insufficient Cu, the liquidus line temperature was not adequate.

[059] In Comparative Examples 8 and 9, due to a low Sb content, the stampability was poor.

[060] In Comparative Example 10, due to a high Sb content, the liquidus line temperature was not suitable.

[061] In Comparative Examples 11 and 12, due to an excessive or insufficient In content, the printability was poor.

[062] In Comparative Example 13, due to a low Ni content, it was not possible to observe homogeneous densification of a joint interface.

[063] In Comparative Example 14, due to a high Ni content, the liquidus line temperature was not suitable.

[064] In Comparative Examples 15 and 16, due to a low Bi content, tensile strength was poor.

[065] In Comparative Examples 17 and 18, due to a high Bi content, formability and tensile strength were poor.

[066] These results will be described using the drawings. Figure 2 shows SEM cross-sectional photographs of solder alloys, Figure 2A illustrates this in Example 3, and Figure 2B illustrates this in Comparative Example 3. As is clear from Figure 2, it can be confirmed that the solder structure was dense in Example 3. On the other hand, in Comparative Example 3, AgaSn was greater than 15 pm, so it was confirmed that all crystal grains were coarse. As described, although the structure became dense and excellent effects were exerted in the Examples where the content of the constituent elements was adequate, the structure did not become dense and the effects deteriorated in the Comparative Examples where the content of at least one of the constituent elements was not adequate.

[067] Figure 3 shows SEM sectional photographs of solder joints, Petition 870260039025, dated 04 / 27 / 2026, page 38 / 78 27 / 27 Figure 3A illustrates this in Example 3 and Figure 3B illustrates this in Comparative Example 13. In Example 3, an intermetallic compound that precipitated at a joint interface was considered homogeneous and fine. On the other hand, in Comparative Example 13, it was not possible to observe the homogeneous densification of a joint interface. Petition 870260039025, dated 04 / 27 / 2026, page 39 / 78

Claims

1 / 3 Claims 1. SOLDER ALLOY, characterized by having an alloy composition consisting of, in % by mass: Ag: 1.0 to 3.8%, Cu: 0.4 to 0.8%, Sb: 0.03 to 2.90%, In: 2.0 to 4.2%, Ni: 0.01 to 0.14%, Bi: 0.1 to 5.0%, Co: 0.100% or less, and at least one of Zr, Fe, Ge, Ga, P, As, Pb, Zn, Mg, Cr, Ti, Mn, Mo, Pt, Pd, Au, Al and Si: 0.1% or less in total, with the remainder being Sn and unavoidable impurities.

2. SOLDER ALLOY, according to claim 1, characterized in that the alloy composition consists of, in % by mass: Ag: 1.0 to 3.8%, Cu: 0.4 to 0.8%, Sb: 0.03 to 2.90%, In: 2.0 to 4.2%, Ni: 0.01 to 0.14%, Bi: 0.1 to 5.0%, and Co: 0.100% or less, with the remainder being Sn and unavoidable impurities.

3. SOLDER ALLOY, according to claim 1, characterized in that the alloy composition consists of, in % by mass: Ag: 1.0 to 3.8%, Cu: 0.4 to 0.8%, Sb: 0.03 to 2.90%, Petition 870260039025, dated 04 / 27 / 2026, p. 40 / 78 2 / 3 In: 2.0 to 4.2%, Ni: 0.01 to 0.14%, Bi: 0.1 to 5.0%, Co: 0.100% or less, and at least one of Zr, As, Pb, Zn, Mg, Ti, Pt, Pd, Au, Al and Si: 0.1% or less in total, with the remainder being Sn and unavoidable impurities.

4. WELDING ALLOY, according to any one of claims 1 to 3, characterized by the alloy composition satisfying the following relation (3): 0.10 < Bi / (In+Sb) < 0.32 Relation (3) where Bi, In and Sb in relation (3) above each represent their content (% by mass) in the alloy composition.

5. WELDING ALLOY, according to any one of claims 1 to 4, characterized by the alloy composition satisfying at least one of the following ratios (1) and (4): 113 < Sn / Cu < 165 Ratio (1) 0.432 < (In+Sb) / (Ag+In+Bi) < 0.999 Ratio (4) wherein Sn, Cu, Ag, Bi, In and Sb in ratios (1) and (4) above each represent the content (% by mass) of the same in the alloy composition.

6. WELDING ALLOY, according to any one of claims 1 to 5, characterized by the alloy composition satisfying the following relation (2): 0.06 < Ag x Ni < 0.19 Relation (2) wherein Ag and Ni in relation (2) above each represent the content (% by mass) of the same in the alloy composition.

7. WELDING SPHERE, characterized by consisting of the welding alloy, as defined in any one of claims 1 to 6.

8. WELD PREFORM, characterized by consisting of the weld alloy, as defined in any one of claims 1 to 6.

9. SOLDERING PASTE, characterized by comprising a soldering powder consisting of the soldering alloy, as defined in any one of claims 1 to 6.

10. WELDED JOINT, characterized by comprising the weld alloy, as defined in any one of claims 1 to 6. Petition 870260039025, dated 04 / 27 / 2026, page 42 / 78

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