JP2014046320A - Solder material and mounting body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem that a conventional solder material does not necessarily have a sufficiently high thermal fatigue property in soldering of an Au electrode on which Au flash plating is carried out by flash treatment for providing thin plating in a short time.SOLUTION: A solder material utilized for soldering of an Au component electrode having Ni plate containing P includes 5.6-6.8 mass% of In, 0.3-4.0 mass% of Ag, 0-1.0 mass% of Bi, 0.025-1.0 mass% of Mo, and the balance of only 87.2 mass% or more of Sn.

Description

  The present invention mainly relates to a solder material and a mounting body in a solder paste or the like used for soldering an electronic circuit board.

  In an electronic circuit board, generally, a Cu substrate electrode whose electrode material is Cu is often used. In general electronic components mounted on an electronic circuit board, Cu component electrodes in which Sn is plated on Cu are used. However, in-vehicle products such as electric compressors, DC / DC converters, inverters, and headlamps, there are cases where Au component electrodes that have been subjected to Au flash plating by flash processing that performs thin plating in a short time may be used. The reason is that, on the joint surface between the Au component electrode and the solder material, the wettability is good, so that a large fillet is formed and the joint reliability is increased. As an example, an electronic circuit board having a Cu substrate electrode and an electronic component having a Cu component electrode or an Au component electrode are joined by soldering to form a mounting body. A schematic cross-sectional view of the mounted body is shown in FIG.

  The mounting body 800 includes an electronic circuit board 830 having Cu substrate electrodes 831 and 832, an electronic component 820 having an Au component electrode 821 on the Cu substrate electrode 831, an electronic component 840 having a Cu component electrode 841 on the Cu substrate electrode 832, The solder portions 811 and 812 are formed using a solder material having a composition of Sn—Ag—Bi—In.

  For the soldering of the electronic circuit board 830 and the electronic components 820 and 840 used here, a solder material having a composition of Sn—Ag—Bi—In composed of four kinds of elements is used. (For example, refer to Patent Document 1). In such a solder material, thermal fatigue characteristics related to fatigue failure caused by thermal stress accompanying temperature change are enhanced by a technique called a solid solution strengthening mechanism. Here, the solid solution strengthening mechanism is a technique that makes it difficult for the solder material to deteriorate by replacing some of the metal atoms arranged in a lattice with different kinds of metal atoms and distorting the lattice.

  In the solder material having the Sn-Ag-Bi-In composition described above, In is dissolved in the Sn lattice, and the thermal fatigue characteristics are enhanced. Specifically, Sn-3.5 mass% Ag A solder material having a composition such as −0.5 mass% Bi-6 mass% In is used. Here, Ag and Bi are added. Ag is added for improving the alloy strength and lowering the melting point by precipitation strengthening, and Bi is added for lowering the melting point.

Japanese Patent No. 3040929

  However, in the case of soldering to the Au component electrode 821, it has been found that a solder material having a composition of Sn—Ag—Bi—In does not necessarily have a sufficiently high thermal fatigue characteristic. On the other hand, in the case of soldering to the Cu component electrode 841, the thermal fatigue characteristics were kept high.

  The inventors have analyzed the reason as follows. That is, in a solder material having a composition of Sn—Ag—Bi—In, the thermal fatigue characteristics change depending on the In content. The thermal fatigue property here is that the occurrence of cracks is not confirmed by observation of the cross section of the soldered joint after the temperature cycle test is carried out under the test conditions of −40 ° C./150° C. (reliability test conditions for in-vehicle products). Shown in number of cycles. For example, the composition of the solder material after soldering is Sn-3.5 mass% Ag-0.5 mass% Bi-6 mass% In and Sn-3.5 mass% Ag-0.5 mass% Bi-5.5 mass% In. , The number of cycles in the temperature cycle test is 2300 cycles and 2150 cycles, and the number of cycles (thermal fatigue characteristics) decreases as In decreases.

  The alloy strength related to thermal fatigue characteristics increases as the In content increases, but becomes maximum when the In content is approximately 6 mass%, and decreases when the In content exceeds this. That is, when the In content is about 6 mass%, the number of cycles in the temperature cycle test is high, so that the thermal fatigue characteristics are the highest. Therefore, in order to effectively use the solid solution strengthening mechanism by In, it is desirable to control the In content of the solder material more accurately.

  This will be described in detail below. First, in a combination of a Cu component electrode and a solder material having a composition of Sn—Ag—Bi—In, Cu and In are not highly reactive, so that the Sn lattice that contributes to the improvement of thermal fatigue characteristics is fixed. Since the In content of the dissolved In does not change during soldering, the thermal fatigue characteristics are kept high.

  On the other hand, for the Au component electrode, Ni plating having a film thickness of 1 to 5 μm is applied on the Cu electrode, and Au flash plating having a film thickness of 0.03 to 0.07 μm is further applied on the Ni plating. In this structure, Au melts into Sn-Ag-Bi-In during soldering with heating, and Ni plating is exposed. Ni plating has a composition of 90 mass% Ni and 10 mass% P, and since In and P are highly reactive, In reacts with P to produce a compound InP having an In-P composition. . As a result, the amount of In dissolved in the Sn lattice, which contributes to the improvement of thermal fatigue characteristics, decreases, and the substantial In content decreases.

  Here, when the In content of the Sn-Ag-Bi-In solder material before soldering is increased in order to enhance the thermal fatigue characteristics of the Au component electrode in which the In content after soldering decreases. The thermal fatigue characteristics of the Au component electrode are enhanced. However, when the same solder material is used in consideration of workability for soldering of an electronic component mounted on one electronic circuit board, the Cu component electrode of the electronic component is made of In before the soldering. On the contrary, the thermal fatigue characteristics decrease depending on the increase in In from the content. Thus, even if the In content of the solder material before soldering is simply increased in order to prevent a decrease in In after the soldering of the Au component electrode, the thermal fatigue characteristics of the Cu component electrode are decreased. Therefore, it was necessary to examine means other than the addition of In.

  The present invention solves the above-mentioned conventional problems, and satisfies the thermal fatigue characteristics of Au component electrodes even in a mounted body after soldering with an electronic component having an Au component electrode mounted on an electronic circuit board. It is an object of the present invention to provide a solder material and a mounting body that can be used.

  In order to achieve the above object, the first aspect of the present invention is a solder material used for soldering an Au component electrode having Ni plating containing P, comprising 5.6 to 6.8 mass% In, It contains 0.3-4.0 mass% Ag, 0-1.0 mass% Bi, 0.025-1.0 mass% Mo, and the balance is only 87.2 mass% or more of Sn. It is a solder material characterized.

  According to a second aspect of the present invention, there is provided a mounting body in which an electronic component having an Au component electrode and an electronic circuit board having a substrate electrode are joined by the solder material of the first aspect.

  According to the configuration of the first invention, it is possible to provide a solder material that can satisfy the thermal fatigue characteristics of the Au component electrode mounted on the electronic circuit board after soldering.

  Moreover, the structure of the said 2nd invention can provide the mounting body with which the Au component electrode mounted in the electronic circuit board after soldering satisfy | filled the thermal fatigue characteristic.

The graph which shows the reliability test result of the alloy with the composition of Sn-3.5mass% Ag-0.5mass% Bi which added In for demonstrating the solder material of Embodiment 1 in this invention. Schematic configuration diagram showing the configuration of the Au electrode prepared as a sample Schematic explanatory diagram for measuring the In content after joining a Cu electrode or an Au electrode prepared as a sample and an alloy having a composition of Sn-3.5 mass% Ag-0.5 mass% Bi-6.0 mass% In For explaining the solder material according to the first embodiment of the present invention, an alloy having a composition of Sn-3.5 mass% Ag-0.5 mass% Bi-6.0 mass% In is used. Graph showing the analysis result of In content in each solder after soldering to the electrode Use of an alloy in which Mo is added to the composition of 90 mass% Sn-3.5mass% Ag-0.5mass% Bi-6.0mass% In for explaining the solder material of the first embodiment in the present invention Then, after soldering to the Au electrode, the graph showing the analysis result of the In content in the solder Schematic sectional view of a mounting body according to an embodiment of the present invention Schematic configuration diagram showing composition of substrate electrode, solder material and component electrode before and after soldering Schematic cross-sectional view of a mounting body using conventional solder materials

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
First, the principle regarding the solder material according to the first embodiment will be described with reference to FIG.

  FIG. 1 is a reliability test of an alloy having a composition of Sn-3.5 mass% Ag-0.5 mass% Bi to which In is added for explaining the solder material according to the first embodiment of the present invention. It is a graph which shows a result.

  In FIG. 1, the In content on the horizontal axis is a substantial In content of In that is dissolved in the solder after soldering, more specifically, In that is dissolved in the Sn lattice. .

  The number of test cycles on the vertical axis is the FR5 board with the FR grade (FR) (Frame Regentant Grade) mounted with a chip capacitor of 1608 size (1.6 mm x 0.8 mm). This is the number of cycles in which generation of cracks was not confirmed by cross-sectional observation of the soldered joint after being performed under the test conditions of 40 ° C./150° C.

  In a reliability test of an in-vehicle product mounted in the vicinity of an automobile engine, a required number of cycles of 2000 cycles or more is required. (Here, it is assumed that the thermal fatigue characteristics are satisfied when the number of cycles is 2000 or more.)

  The number of cycles is 2000 when the In content dissolved in the solder after soldering is 5.5 mass% (2150 cycles), 6.0 mass% (2300 cycles), and 6.5 mass% (2200 cycles). Although it is more than a cycle, when In content is 5.0 mass% or less or 7.0 mass% or more, it is less than 2000 cycles.

A quadratic function obtained by using an approximate curve using the above numerical data (Expression 1)
(Number of test cycles)
= −410.7 × (In content) ² + 4919.6 × (In content) -12446
It is illustrated as a graph.

  Therefore, the range of the In content that can secure the number of cycles of 2000 cycles or more, which is the vehicle-mounted standard, is approximately 5.2 to 6.8 mass%, and the management width is approximately ± 0.8 mass%.

  Since the variation range of the In content of the solder alloy in mass production is about ± 0.5 mass%, the In content is 4.7 (= 5.2-0.5) mass% or more and 7.3 (= It may be 6.8 + 0.5) mass% or less, but is more preferably 5.7 (= 5.2 + 0.5) mass% or more and 6.3 (= 6.8−0.5) mass% or less.

  Next, the influence of P contained in the Ni plating will be described with reference mainly to FIGS.

  As the Au electrode and Cu electrode used here, a sample prepared for measurement is used.

  FIG. 2 is a schematic configuration diagram showing a configuration of an Au electrode prepared as a sample. FIG. 3 shows a Cu electrode and an Au electrode prepared as a sample and Sn-3.5 mass% Ag-0.5 mass% Bi-6. It is a schematic explanatory drawing which measures In content rate after joining with the alloy which has a composition of 0.0 mass% In.

  The Au electrode prepared as a sample is a Cu foil with a Cu electrode having a film thickness of 35 μm, and Ni plating with a film thickness of 1 to 5 μm is used as an electroless plating that does not require energization like electroplating. The Au flash plating having a film thickness of 0.03 to 0.07 μm is applied on the Ni plating.

  For example, the thickness of Ni plating is 3 μm, and the thickness of Au flash plating is 0.05 μm.

  Solder material having a composition of Sn-3.5 mass% Ag-0.5 mass% Bi-6.0 mass% In is supplied on the Cu electrode and Au electrode in a shape of 5 mm in diameter and 0.15 mm in thickness, respectively. And heated on a hot plate at 240 ° C. for 30 seconds and slowly cooled at room temperature.

  The center part of the cross section polished so that the vertical cross section appears is analyzed by a method using EDX (Energy Dispersive X-ray spectroscopy), and the In content is measured.

  Here, the central portion is a position corresponding to a position at a half of the thickness of the solder and a half of the solder spreading width.

  FIG. 4 shows an example in which an alloy having a composition of Sn-3.5 mass% Ag-0.5 mass% Bi-6.0 mass% In is used after soldering to a Cu electrode and an Au electrode. It is a graph about the analysis result of In content rate in the inside of solder.

  The measured substantial In content of In dissolved in the Sn lattice contributing to the improvement of thermal fatigue properties has decreased from the initial In content of 6.0 mass%, It is 5.9 mass% for the Cu electrode, and a smaller 5.1 mass% for the Au electrode.

  As for the Au electrode, Au diffuses into the solder during heating, and Ni plating having a composition of 90 mass% Ni and 10 mass% P formed under the Au flash plating is exposed.

  As described above, since In reacts with P to produce compound InP, the amount of In dissolved in the Sn lattice decreases, and the substantial In content in the case of the Au electrode is the same as that of the Cu electrode. Compared with the case, it will be greatly reduced.

  For this reason, since the range of In content corresponding to the vehicle-mounted standard is approximately 5.2 to 6.8 mass% as described above, the Au electrode does not satisfy the vehicle-mounted standard.

Since the specific gravity of Ni plating is 7.9 g / cm ³ , the weight of P contained in the Ni plating is 7.9 × T × using the Ni plating film thickness T and the Ni plating area S. The weight of P contained in the Ni plating varies in proportion to the thickness T of the Ni plating.

  Based on such a phenomenon, the present inventors have found that the addition of an element that easily reacts with P more easily than In is effective for suppressing a decrease in In content.

An element found as such element among many elements reacts with P to produce compounds such as MoP ₂ , MoP, Mo ₄ P ₃ , Mo ₃ P, which will be described below. (Molybdenum).

  Here, the solder material according to the present embodiment will be specifically described with reference to FIG.

  FIG. 5 is a graph showing the composition of 90 mass% Sn-3.5 mass% Ag-0.5 mass% Bi-6.0 mass% In for explaining the solder material according to the first embodiment of the present invention. It is a graph which shows the analysis result of In content rate in the solder after soldering with respect to Au electrode was performed using the added alloy.

  First, the lower limit of the Mo content will be described.

  Here, the analysis is performed by the same method as described above, and the In content after the soldering with the Au electrode is measured.

  The sample is prepared as follows.

  89.7 g of Sn is put in a ceramic crucible and left in an electric jacket heater whose temperature is adjusted to 500 ° C.

  6.0 g of In is added after it is confirmed that Sn has melted, and stirring is performed for 3 minutes.

  0.5 g of Bi is charged and stirring is further performed for 3 minutes.

  3.5 g of Ag is charged and stirring is further performed for 3 minutes.

  0.3 g of Mo is charged and stirring is further performed for 3 minutes.

  Thereafter, the crucible is taken out from the electric jacket heater and immersed in a container filled with water at 25 ° C. to be cooled.

  The In content is (1) 5.1 mass% when the Mo content is zero, but (2) When the Mo content increases, the decrease in In is suppressed, 3) When the Mo content is 0.2 mass%, it becomes 5.62 mass%, and (4) When the Mo content becomes 0.4 mass%, it becomes almost 6.03 mass%.

  (5) Even if the Mo content is 0.5 mass%, 0.6 mass%, 0.7 mass%, and 0.8 mass%, there is almost no change in the In content.

When an approximate straight line is drawn using numerical values when the Mo content is 0 mass% to 0.4 mass%, a linear function (Equation 2)
(In content)
= 2.33 x (Mo content) + 5.142
Is obtained.

  Therefore, in order to secure the In content of 5.2 mass% or more necessary for satisfying the on-vehicle standard even in combination with the Au electrode, the Mo content is preferably 0.025 mass% or more. If the Mo content is 0.025 mass% or more, the In content after soldering is 5.2 mass% or more even in combination with the Au electrode, and the reliability of the on-vehicle standard can be satisfied.

  However, since the fluctuation range of the In content of the solder alloy in mass production is about ± 0.5 mass%, the In content may be slightly reduced for that reason.

In such a case, the approximate straight line is a linear function in which the graph of (Equation 2) has undergone a downward movement corresponding to −0.5 mass%, which is the lower limit of the fluctuation range in mass production (Equation 3)
(In content)
= 2.33 × (Mo content) +4.642
The In content is 4.7 mass% when the Mo content is 0.025 mass%.

  Therefore, when the lower limit of the fluctuation range in mass production is considered, in order to secure an In content of 5.2 mass% or more, the Mo content has a margin of 0.24 mass% or more (this value is (5 2−4.662) /2.33=0.239≈0.24). In the above description, the case where an alloy having a composition of 90 mass% Sn-3.5 mass% Ag-0.5 mass% Bi-6.0 mass% In is used has been described. Changes at a constant ratio, so even when the In content is different, it can be handled accordingly.

  Next, the upper limit of the Mo content will be described.

  That is, if the Mo content is too large, the viscosity at the time of melting increases and the fluidity decreases, so that the wettability to the electrode tends to deteriorate.

  More specifically, when Mo is added to the Sn-based solder, an intermetallic compound having a MoSn2 composition is generated. Since the melting point of the intermetallic compound having the MoSn2 composition is 600 ° C., Sn melts into a liquid state at a soldering temperature of 250 to 260 ° C., but MoSn2 is in a solid state. Therefore, the solid particles are suspended in the liquid. Here, since the amount of solid particles increases when the amount of added Mo increases, the fluidity of the liquid decreases.

  Table 1 explains the relationship between the Mo content and the wetting spread when the Mo content is 0.1 mass%, 0.2 mass%,..., 2.0 mass%. (The same applies to the other tables, but the unit attached to the numerical data is mass%).

  Here, it is assumed that the Ni plating film thickness approaches the lower limit and the P content is minimum, and the wetting spreadability is not good from this viewpoint, so that the Ni plating film thickness is 1 μm. For the prepared sample, the wetting spread rate is measured by the spread test method defined in JIS Z 3197 “Flux test method for soldering”.

  Regarding the evaluation of the wetting spread, ◯ indicates that the wetting spread rate is 90% or more, Δ indicates that the wetting spread rate is 85% or more and less than 90%, and x indicates the wetting spread rate. Is less than 85%.

  Therefore, in order to guarantee a wetting spread rate of 90% or more which is important for good soldering, it is desirable that the Mo content is 1.0 mass% or less.

  Table 2 explains the relationship between the various compositions of the solder material before soldering and the change in the In content of the solder material after soldering for the compositions 1 to 4 and the comparative example, and the reliability is determined. .

  The remaining amount with respect to the change in the In content is measured by performing an analysis of the In content in the solder after the soldering to the Au electrode is performed using EDX.

  Regarding the determination about the change in the In content, ○ indicates that the In content after soldering is included in the range of 5.2 to 6.8 mass%, and × indicates the In content. Is in the range of less than 5.2 mass%.

  Regarding reliability judgment, ○ indicates that the standard is satisfied, based on the fact that the number of cycles of the temperature cycle test in the reliability test of in-vehicle products satisfies the required specification of 2000 cycles or more, × Indicates that the standard is not satisfied.

  From the reliability determination of the compositions 1 to 4, it can be seen that the decrease in the In content is suppressed by the inclusion of Mo in the solder material having the Sn-Ag-Bi-In composition.

  In the comparative example, since an effective element was not added to suppress a decrease in the In content, the In content after soldering was 5.1 mass% (the change in In content was -0.9 mass%). ), The judgment about that is x.

  Next, Table 3 explains the relationship between various compositions of the solder material not containing Bi and changes in the In content for compositions 5 to 8, and the reliability is determined. The various determinations are the same as in Table 2 above.

  In the compositions 5 to 8 in Table 3, since the reliability determination results all satisfy the standard, it can be seen that the change in In content is not affected even if Bi is not contained in the solder material. .

  Bi of the solder material is added to adjust the melting temperature of the alloy, and the amount of Bi does not affect the thermal fatigue characteristics of the solder material.

  From the results of the reliability determination in Tables 2 and 3, the Mo content is 0.025 mass% or more and 1.0 mass in order to satisfy the reliability evaluation of the in-vehicle product even in soldering to the Au electrode. When the lower limit of the fluctuation range in mass production is taken into consideration, the Mo content is more preferably 0.24 mass% or more and 1.0 mass% or less with a slight margin.

  Moreover, the content rate of Ag which comprises the solder material in embodiment is determined for the following reasons. As described above, since the thermal fatigue characteristics are improved by the solid solution strengthening action of In against Sn, the thermal fatigue characteristics vary greatly depending on the amount of In. However, since Ag does not dissolve in Sn, thermal fatigue characteristics do not change greatly.

Moreover, since the amount of Ag affects the melting point of the solder material, if the Ag content exceeds 4 mass%, the melting point becomes 235 ° C. or more, and the wetting and spreading during soldering deteriorates, so it cannot be used. Therefore, the maximum value of the Ag content is set to 4 mass%. Further, when the Ag content is decreased, the amount of Ag ₃ Sn deposited on the Sn phase is decreased and the mechanical strength characteristics are lowered. Therefore, the minimum value of the Ag content is set to 0.3 mass%.

  Next, the content rate of Bi which comprises the solder material in embodiment is determined for the following reasons. As described in Table 3, the minimum value can be zero because it does not affect the thermal fatigue characteristics of the solder material. Further, since Bi has a property of segregating inside the solder alloy, if it exceeds 1 mass%, the amount of segregation increases, and the alloy becomes brittle and cannot be used. Therefore, the maximum value of Bi content was set to 1 mass%.

  From the above, since Ag and Bi do not affect the thermal fatigue characteristics of the solder material, the effect of the In content in Sn-Ag-Bi-In is similarly handled in Sn-Ag-In and Sn-Bi-In. I think you can.

  As for the composition of the solder material, “the composition of 90 mass% Sn-3.5 mass% Ag-0.5 mass% Bi-6.0 mass% In to which Mo (for example, 0.1 mass%) is added” in FIG. However, when this is replaced with the composition notation of the solder material in Tables 2 and 3, "89.9 mass% Sn-3.5 mass% Ag-0.5 mass% Bi-6.0 mass% In-0. 1 mass% Mo ”, and the Sn content is reduced by the addition of Mo. It is considered that a slight change in Sn does not affect the change in the In content.

  As is clear from the above description, the solder material of the present invention is a solder material used for soldering an Au component electrode having Ni plating containing P, and includes 5.6 to 6.8 mass% In. And 0.3-4.0 mass% Ag, 0-1.0 mass% Bi, 0.025-1.0 mass% Mo, and the balance is only 87.2 mass% or more of Sn. It is characterized by that.

  The mounting body of the present invention is characterized in that an electronic component having an Au component electrode and an electronic circuit board having a substrate electrode are joined by the solder material described above, and is mounted on the electronic circuit board after soldering. It is possible to provide a mounting body that can satisfy the thermal fatigue characteristics of the Au component electrode.

  Further, the amount of Mo contained is desirably an amount corresponding to the amount of P contained in the Ni plating.

  Moreover, since the solder part formed using the solder material having the composition of Cu electrode and Sn-Ag-Bi-In-Mo does not form an intermetallic compound with Cu and Mo, thermal fatigue characteristics The degree of influence is considered to be small.

  FIG. 6 shows a schematic cross-sectional view of the mounting body according to the embodiment of the present invention. The mounting body 600 includes an electronic circuit board 630 having Cu substrate electrodes 631 and 632, an electronic component 620 having an Au component electrode 621 on the substrate electrode 631, an electronic component 640 having a Cu component electrode 641 on the substrate electrode 632, and Sn −. They are joined by solder portions 611 and 612 formed using a solder material having a composition of Ag-Bi-In-Mo. The mounting body 600 having such a configuration satisfies the required specifications for the reliability test of the in-vehicle product.

  Further, the substrate electrodes 631 and 632 may be Au electrodes.

Moreover, the schematic block diagram before and behind soldering of the solder part 611 and the board | substrate electrode 631 which were formed using the solder material which has the composition of Au component electrode 621 and Sn-Ag-Bi-In-Mo is shown. 7 shows. The figure shown on the left side of FIG. 7 shows the configuration before soldering, and the figure on the right side at the tip of the arrow shows after soldering. In the Au component electrode having Ni plating containing P, a MoP ₂ compound indicated by a small circle is formed on the solder portion after soldering. Formation of this MoP ₂ compound helps to prevent a decrease in In content in the solder material.

  In addition, Mo was added to the solder material having the Sn-Ag-Bi-In composition this time, but even if Co (cobalt) or Ga (gallium) is used in place of Mo, the inclusion of In in the solder material Helps prevent rate decline.

  The solder material and the mounting body in the present invention can satisfy thermal fatigue characteristics even in soldering to an Au component electrode, and are useful for use in, for example, a solder paste used for soldering an electronic circuit board. .

600 Mounting body 611, 612 Solder part 620, 640 Electronic component 621 Au component electrode 630 Electronic circuit board 631, 632 Cu substrate electrode 641 Cu component electrode

Claims (2)

A solder material used for soldering an Au component electrode having Ni plating containing P,
5.6 to 6.8 mass% In,
0.3 to 4.0 mass% Ag;
0 to 1.0 mass% Bi,
Containing 0.025 to 1.0 mass% Mo,
The balance is only 87.2 mass% or more of Sn, which is a solder material.   An electronic component having an Au component electrode and an electronic circuit board having a substrate electrode are joined by the solder material according to claim 1.

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