JP4453612B2 - Lead-free solder alloy - Google Patents

Description

  The present invention relates to a lead-free solder alloy, and particularly to a lead-free solder alloy suitable for joining inside an electronic component.

  Conventionally, solder mainly composed of Pb and Sn has been used as a material for connecting electronic components. As a solder used for mounting an electronic component on a substrate, a eutectic solder having a low melting point, for example, a eutectic solder containing 37 mass% Pb in Sn (hereinafter referred to as “Sn / 37 mass% Pb In the following, a simplified description is often used for solders having other compositions as well. The melting point of the Sn / 37 mass% Pb eutectic solder is as low as 183 ° C.

  On the other hand, high-temperature solder having a high melting point is often used for connection inside an electronic component, for example, connection between a lead frame and a chip. This is because when the electronic component is mounted on the substrate, reflow is performed at 220 to 230 ° C., so that the reliability of the joint is lowered when the solidus line of the high-temperature solder inside the electronic component is equal to or lower than the reflow temperature.

  For this reason, it is necessary to use a solder having a solidus temperature higher than the reflow temperature at the time of mounting on the board for joining inside the electronic component. Pb / 5 mass% Sn (solidus temperature 305 ° C.), Pb / A high-temperature solder mainly composed of Pb and Sn such as 3 mass% Sn (solidus temperature 315 ° C.) is used. In addition to the melting point, characteristics required for high-temperature solder include heat dissipation, stress relaxation, thermal fatigue resistance, electrical conductivity, and the like. This is because a large current load is applied and a large amount of heat is generated.

  However, while solder containing lead is often used as a solder for joining electronic components, there is a risk that lead will flow out from discarded products and penetrate into the soil, and lead may accumulate in agricultural products and harm humans. Has been pointed out. Furthermore, it has been pointed out that lead spillage from discarded products has been accelerated by acid rain, increasing the risk of human health damage from lead.

  For this reason, lead-free solder containing no Pb such as Sn—Ag—Cu has begun to be used as a substitute for a eutectic solder having a low melting point used when mounting electronic components on a substrate. However, the melting point of lead-free solder such as Sn—Ag—Cu is higher than that of a conventional eutectic solder and is about 220 ° C. In order to perform reflow using this solder, the reflow temperature during mounting is 250 to 260. It will be necessary to raise it to around ℃. Patent Document 1 describes conditions required for such mounting.

  On the other hand, there is Sn—Sb solder as one of lead-free solders used for die bonding, which is a bonding inside an electronic component, and one having Sb of 10% by mass or less is mainly used. The Sn—Sb solder with Sb of 10% by mass or less has a solidus temperature / liquidus temperature of 246 ° C. or less.

  For this reason, when lead-free solder such as Sn-Ag-Cu is used to mount an electronic component die-bonded with Sn-Sb solder with Sb of 10% by mass or less on a substrate, Sn-Sb is used during reflow. There is a possibility that the solder may be completely melted, the jointability inside the electronic component is impaired, and the function as the electronic component may not be performed.

  In addition, there are Au—Sn alloy, Bi—Ag alloy, etc. as the alloy system not containing Pb having a solidus of 260 ° C. to 320 ° C., but the Au—Sn alloy is expensive and not practical in terms of cost. The Bi—Ag alloy proposed in Patent Document 2 (Japanese Patent Laid-Open No. 2002-160089) and the like is mainly composed of Bi, which has a lower thermal conductivity than Pb alloy and Sn alloy, and therefore has a heat dissipation property. There's a problem.

JP 2002-321084 A JP 2002-160089 A

  The present invention has been made in view of such problems, and has a high melting point, good heat resistance, improved wettability and thermal fatigue strength characteristics, and is used for mounting electronic components on a board. Providing lead-free solder alloys that can be suitably used for die bonding, which is an internal joint of electronic components, without the adverse effects of heat during reflow even when lead-free solder with a relatively high melting point is used as the solder The purpose is to do.

  The first aspect of the lead-free solder alloy according to the present invention includes Cu in excess of 10% by mass and 24.9% by mass or less, Sb in an amount of 5% by mass or more, the balance being Sn, and the Sn content. Is more than 70% by mass.

  The second embodiment of the lead-free solder alloy according to the present invention contains Cu in excess of 10% by mass and 24.9% by mass or less, Sb in an amount of 5% by mass or more, and Te in a range of 0.01% by mass to 5% by mass. The remainder is made of Sn, and the Sn content exceeds 70% by mass.

  A third aspect of the lead-free solder alloy according to the present invention includes at least one selected from the group consisting of more than 10% by weight of Cu and 24.9% by weight or less, Sb of 5% by weight or more, and P and Ge. It is characterized by containing 0.001 mass% or more and 0.5 mass% or less of elements in total, the remainder consists of Sn, and content of Sn exceeds 70 mass%.

  In a fourth embodiment of the lead-free solder alloy according to the present invention, Cu exceeds 10% by weight and is 24.9% by weight or less, Sb is 5% by weight or more, Te is 0.01% by weight or more and 5% by weight or less, P And at least one element selected from the group consisting of Ge and 0.001% by mass or more and 0.5% by mass or less, the balance being Sn, and the Sn content exceeding 70% by mass It is characterized by that.

  According to a fifth aspect of the lead-free solder alloy of the present invention, Sb is 5% by mass or more, Cu is 5% by mass or more, and one or more elements selected from the group consisting of Ag, Au, and Pd are added in a total amount of 0.0. 1% by mass or more, the total content of Cu, Ag, Au and Pd is more than 10% by mass and 24.9% by mass or less, the balance is Sn, and the Sn content is 70% by mass It is characterized by exceeding.

  A sixth aspect of the lead-free solder alloy according to the present invention is a group consisting of Sb of 5 mass% or more, Cu of 5 mass% or more, Te of 0.01 mass% or more and 5 mass% or less, Ag, Au, and Pd. The total content of one or more selected elements is 0.1% by mass or more, the total content of Cu, Ag, Au and Pd is more than 10% by mass and 24.9% by mass or less, and the balance is Sn And the Sn content exceeds 70% by mass.

  In a seventh embodiment of the lead-free solder alloy according to the present invention, Sb is 5% by mass or more, Cu is 5% by mass or more, and at least one element selected from the group consisting of P and Ge is 0.001 in total. % Or more and 0.5% by mass or less, containing at least 0.1% by mass in total of one or more elements selected from the group consisting of Ag, Au and Pd, and the total content of Cu, Ag, Au and Pd is More than 10 mass% and 24.9 mass% or less, the remainder consists of Sn, and Sn content exceeds 70 mass%.

  An eighth aspect of the lead-free solder alloy according to the present invention is selected from the group consisting of Sb of 5 mass% or more, Cu of 5 mass% or more, Te of 0.01 mass% or more and 5 mass% or less, P and Ge. In addition, 0.001% by mass or more and 0.5% by mass or less of one or more elements in total, and one or more elements selected from the group consisting of Ag, Au and Pd in total containing 0.1% by mass or more. , Cu, Ag, Au, and Pd have a total content of more than 10% by mass and 24.9% by mass or less, the remainder is made of Sn, and the Sn content is more than 70% by mass To do.

  Since the lead-free solder alloy according to the present invention does not contain Pb, it has a high melting point, good heat resistance, and improved wettability and thermal fatigue strength characteristics. Even if a lead-free solder having a relatively high melting point is used as the solder for use, there is no adverse effect due to heat during reflow, and it can be used for die bonding or the like, which is a joint inside an electronic component. In addition, wettability and thermal fatigue strength can be improved by adding predetermined amounts of Te, P, and Ge.

  There is Sn-Sb solder as a lead-free solder for joining inside an electronic component that has a higher solidus line than the lead-free solder used when mounting the electronic component on a substrate and does not contain lead. Sn—Sb solder is a peritectic alloy. A peritectic alloy is an alloy system that does not lower a melting point due to alloying unlike a eutectic alloy. Therefore, Sn—Sb solder has a melting point higher than that of Sn (232 ° C.), and when Sb is contained in an amount of 10% by mass or more, the solidus temperature becomes 246 ° C., and it is practical as a solder as an Sn-base alloy. It is an alloy system with the highest possible solidus.

  The present inventor made Sn-Sb solder as a base and added another predetermined element in excess of 10% by mass to raise the liquidus, so that 260 ° C. (reflow using lead-free solder for mounting) It has been found that the melting rate of the lead-free solder for bonding at the reflow temperature (which is assumed when performing soldering) can be reduced, and the initial shape of the solder inside the electronic component can be maintained even after mounting.

  The present inventor has focused on Cu, Ag, Au, and Pd as elements that have the effect of increasing the liquidus when added. When these elements are added to the Sn-based alloy, the liquidus increases as the addition amount increases. And when this inventor adds Cu, Ag, Au, and Pd to a Sn-Sb solder alloy, liquidus temperature rises further, the fusion rate in a solidus line reduces significantly, and it is 260 degreeC. It has been found that the melting rate of the solder can be reduced.

  Further, an increase in the Sb content also raises the liquidus, but the ratio of the hard and brittle intermetallic compound of Sn and Sb (hereinafter referred to as β ′ phase) increases. In addition, the increase in the β ′ phase and the increase in intermetallic compounds generated by the additive elements make the Sn—Sb solder alloy hard and brittle, so that chip cracks and the like occur after bonding. Therefore, in order to suppress this phenomenon, the present inventor has conducted intensive research and development, contains Sn in excess of 70% by mass, and leaves the Sn single phase, thereby achieving both mechanical properties and reliability after bonding. I found out that I can make it.

  Further, in the Sn—Sb alloy, when the Sb content is 10% by mass or more, a β ′ phase is crystallized as an initial crystal during solidification. For this reason, the β ′ phase may be present in a coarse form in the solder, and in this case, there is a possibility that poor wetting may occur during use. Furthermore, a coarse β ′ phase may be present in the solidified structure after die bonding, and in this case, chip cracks are caused. In response to this, the present inventor can refine the solidification structure by adding Te, which is an element that crystallizes at a temperature higher than the liquidus temperature of the Sn—Sb alloy. I found out that I can.

  Furthermore, the present inventor has found that it is effective to add P or Ge in order to improve the wettability of the solder and reduce the generation of voids during bonding.

  The solder alloy according to the present invention has been completed based on the above findings. Hereinafter, the solder alloy according to the present invention will be described in detail.

"Sn"
The necessary Sn content is an amount exceeding 70% by mass. As described above, when the Sn content is 70% by mass or less, the ratio of hard and brittle intermetallic compounds such as Sn—Sb and Sn—Cu increases, the stress relaxation property as solder disappears, and the chip after bonding Cracks occur. The upper limit of the required Sn content is Sb, Cu, which are other essential additive elements necessary in the present invention, and Te, P, Ge, Ag, Au, Pd, which are elements that are preferably added. It depends on the minimum amount required.

"Sb"
The required Sb content is 5% by mass or more. If it is less than 5% by mass, a decrease in heat resistance due to a decrease in solidus will occur, and the initial shape after soldering will change. The upper limit value of the necessary Sb content is the minimum necessary amount of Sn, Cu, which are other essential additive elements necessary in the present invention, and Te, P, Ag, Au, Pd, which are elements preferably added. It depends on the amount added.

"Cu, Ag, Au, Pd"
Cu, Ag, Au, and Pd are effective in increasing the liquidus temperature. The Cu content necessary for the alloy of the first aspect according to the present invention is more than 10% by mass and 24.9% by mass or less. When the content of Cu is 10% by mass or less, when the solder melts during reflow (260 ° C.) after the solder joint, the melt amount becomes too large, and the initial shape after the solder joint is changed. Therefore, the role as a bonding material cannot be fulfilled. Further, if the Cu content exceeds 24.9% by mass, it becomes hard and brittle, so that defects such as chip cracks often occur after bonding.

  In addition to Cu, the alloy of the fifth aspect according to the present invention, which adds Ag, Au, and Pd, which has the effect of raising the liquidus like Cu, is obtained by adding 5% by mass or more of Cu. One or more elements selected from the group consisting of Au and Pd are added in a total amount of 0.1% by mass or more, and the total content of Cu, Ag, Au and Pd exceeds 10% by mass and 24.9% by mass % Or less. Thereby, in heat resistance, the same effect as when Cu content exceeds 10 mass% and is 24.9 mass% or less (the alloy of the first aspect according to the present invention) is obtained.

  Addition of Ag, Au and Pd is effective in improving thermal fatigue strength in addition to heat resistance. If the total addition amount of one or more elements selected from the group consisting of Ag, Au and Pd is less than 0.1% by mass, this effect is hardly obtained. On the other hand, if the total content of Cu, Ag, Au, and Pd exceeds 24.9% by mass, it becomes hard and brittle, and defects such as chip cracks often occur after bonding.

"Te"
Te is effective in reducing the solidification structure. The reason why such an effect is obtained by adding Te is that Te is an element that crystallizes at a temperature higher than the liquidus temperature of the Sn—Sb alloy, and the added Te is the liquidus line of the Sn—Sb alloy. This is presumably because it crystallizes at a temperature higher than the temperature and becomes the nucleus of primary crystal formation of the peritectic alloy and contributes to the refinement of the solidified structure. It is considered that the β ′ phase can be refined by making many primary crystal nuclei exist.

  The necessary amount of Te added is 0.01 to 5% by mass. When the added amount of Te exceeds 5% by mass, the effect of refining the β ′ phase is reduced. On the other hand, when the amount of Te added is less than 0.01% by mass, the number of primary crystal formation nuclei in the peritectic alloy is reduced, and it does not sufficiently contribute to the refinement of the solidified structure.

"P, Ge"
P and Ge are effective in improving the wettability of the solder and reducing the generation of voids during bonding. The reason why such an effect can be obtained by adding P and / or Ge is presumably because P and Ge are preferentially oxidized and oxidation of the solder surface is suppressed. The required total addition amount of P and / or Ge is 0.001 to 0.5 mass%. If the total addition amount exceeds 0.5% by mass, P and / or Ge will form many oxides, resulting in poor wettability. Moreover, when the total addition amount is less than 0.001% by mass, the effect of adding P and / or Ge becomes insufficient.

(Examples 1 and 2, Examples 5 to 9, Comparative Examples 3, 4, 10, and 11)
Using Sn, Sb, and Cu with a purity of 99.99 mass%, an Sn alloy having the composition shown in Table 1 was melted using an air melting furnace, extruded to 1 mmφ, and a wire-shaped solder alloy was produced. .

  In order to evaluate the wettability of the obtained solder alloy, the wire was subjected to a melting test in a lead frame island heated to 400 ° C. in a nitrogen atmosphere, and gradually cooled after melting. Although a melting test was performed on 200 samples for each composition, no wetting failure was confirmed, and the wettability was good.

  Next, die bonding was performed using each of the obtained samples, and the reliability of the bonded portion was evaluated. The evaluation method is specifically described below. Using the 1 mmφ sample and a die bonder, a dummy chip produced by vapor-depositing Au on the die bonding surface of a silicon chip was die-bonded to a copper lead frame. Next, this was molded with an epoxy resin. 500 cycles of a temperature cycle test at −50 ° C./150° C. were performed using the molded product. Thereafter, the resin was opened and the bonded portion was observed by die bonding, and the case where no crack occurred in the chip and the bonded portion was evaluated as “good”, and the case where a crack occurred was evaluated as “bad”. The results are shown in Table 1.

  As shown in Table 1, in Comparative Example 3, the content of Cu is 10% by mass or less, and the content of Sb is less than 5% by mass, which is not within the scope of the present invention. In Comparative Examples 4, 10, and 11, the Sn content does not exceed 70% by mass and does not fall within the scope of the present invention.

  For this reason, although cracks did not occur in the chips or joints in Comparative Example 3 by the above temperature cycle test, cracks occurred in the chips or joints in Comparative Examples 4, 10, and 11, and the reliability of the joints was improved. The evaluation result was “bad”.

  For Examples 1 and 2 and Examples 5 to 9 that are within the scope of the present invention, even in the above temperature cycle test, the chip and the joint were not cracked, and the evaluation result of the joint reliability was “good”. "

  Next, a part of the molded product was mounted on a substrate at a reflow temperature of 260 ° C., and the presence or absence of abnormality in the chip and the joint after mounting was examined. As a result, in Comparative Example 3, the solder part melted due to the influence of heat during mounting, the solder flowed out, the initial shape of the solder was changed, and the heat resistance was “bad”. In all other cases, no abnormality was observed, and no conspicuous voids could be confirmed.

  Moreover, although the heat resistance evaluation of the site | part joined with the solder alloy which concerns on this invention (Example 1, 2, Examples 5-9) was implemented by hold | maintaining for 10 second at 260 degreeC which is reflow temperature, It was confirmed that only a part of the melted portion was melted in any joint, and the whole was kept without melting. Therefore, the part joined by the solder alloy according to the present invention (Examples 1 and 2 and Examples 5 to 9) does not cause peeling or void even during reflow for mounting the electronic component on the substrate. Therefore, it is considered that no problem occurs in the characteristics of the electronic component.

(Examples 12 to 21)
Using Sn, Sb, Cu, Te, P with a purity of 99.99 mass%, an Sn alloy having the composition shown in Table 2 is melted using an air melting furnace, extruded to 1 mmφ, and wire-shaped solder An alloy was made.

  In order to evaluate the wettability of the obtained solder alloy, the wire was subjected to a melting test in a lead frame island heated to 400 ° C. in a nitrogen atmosphere, and gradually cooled after melting. Although a melting test was performed on each of the 200 samples for each composition, no wetting failure was confirmed, and the wetting spread was greater than in Examples 1, 2, Examples 5-9, and Comparative Examples 3, 4, 10, and 11. It became favorable and wettability improved.

  Next, die bonding was performed using each of the obtained samples, and the reliability of the bonded portion was evaluated. The evaluation method is specifically described below. Using the 1 mmφ sample and a die bonder, a dummy chip produced by vapor-depositing Au on the die bonding surface of a silicon chip was die-bonded to a copper lead frame. Next, this was molded with an epoxy resin. Using the molded product, the temperature cycle test of −50 ° C./150° C. was increased to 1000 cycles. Thereafter, the resin was opened and the bonded portion was observed by die bonding, and the case where no crack occurred in the chip and the bonded portion was evaluated as “good”, and the case where a crack occurred was evaluated as “bad”. The results are shown in Table 2.

  As shown in Table 2, for Examples 12 to 21 within the scope of the present invention, the chip and the joint did not crack even by the above temperature cycle test. It was good.

  Next, a part of the molded product was mounted on a substrate at a reflow temperature of 260 ° C., and the presence or absence of abnormality in the chip and the joint after mounting was examined. As a result, no abnormality was observed, and no conspicuous voids could be confirmed.

  Moreover, although the heat resistance evaluation of the site | part joined with the solder alloy which concerns on this invention (Examples 12-21) was implemented by hold | maintaining at 260 degreeC which is a reflow temperature for 10 second, in any junction part It was confirmed that only a part melted and the whole was kept without melting. Therefore, the part joined by the solder alloy according to the present invention (Examples 12 to 21) does not cause peeling or void even during reflow for mounting the electronic component on the substrate, and the characteristics of the electronic component are not affected. The problem is not expected to occur.

(Examples 22 to 26)
Using Sn, Sb, Cu, and Ag with a purity of 99.99 mass%, an Sn alloy having the composition shown in Table 3 is melted using an air melting furnace and extruded to 1 mmφ to produce a wire-shaped solder alloy. did.

  In order to evaluate the wettability of the obtained solder alloy, the wire was subjected to a melting test in a lead frame island heated to 400 ° C. in a nitrogen atmosphere, and gradually cooled after melting. A melting test was conducted on 200 samples for each composition, but no wetting defect was confirmed.

  Next, die bonding was performed using each of the obtained samples, and the reliability of the bonded portion was evaluated. The evaluation method is specifically described below. Using the 1 mmφ sample and a die bonder, a dummy chip produced by vapor-depositing Au on the die bonding surface of a silicon chip was die-bonded to a copper lead frame. Next, this was molded with an epoxy resin. Using the molded product, a temperature cycle test of −50 ° C./150° C. was performed 800 cycles. Thereafter, the resin was opened and the bonded portion was observed by die bonding, and the case where no crack occurred in the chip and the bonded portion was evaluated as “good”, and the case where a crack occurred was evaluated as “bad”. The above results are shown in Table 3.

  As shown in Table 3, for Examples 22 to 26 that are within the scope of the present invention, cracks did not occur in the chip or the joint even by the above-described temperature cycle test, and the evaluation result of the joint reliability was “ It was good.

  Next, a part of the molded product was mounted on a substrate at a reflow temperature of 260 ° C., and the presence or absence of abnormality in the chip and the joint after mounting was examined. As a result, no abnormality was observed, and no conspicuous voids could be confirmed.

  Moreover, although evaluation of the heat resistance of the site | part joined with the solder alloy which concerns on this invention (Examples 22-26) was implemented by hold | maintaining at 260 degreeC which is a reflow temperature for 10 second, in any joined part. It was confirmed that only a part melted and the whole was kept without melting. Therefore, the part joined by the solder alloy according to the present invention (Examples 22 to 26) does not cause peeling or void even during reflow for mounting the electronic component on the substrate, and the characteristics of the electronic component are not affected. The problem is not expected to occur.

(Examples 27 to 36)
Using Sn, Sb, Cu, Ag, Te, P with a purity of 99.99% by mass, an Sn alloy having the composition shown in Table 4 is melted using an air melting furnace, extruded to 1 mmφ, and wire shape A solder alloy was prepared.

  In order to evaluate the wettability of the obtained solder alloy, the wire was subjected to a melting test in a lead frame island heated to 400 ° C. in a nitrogen atmosphere, and gradually cooled after melting. Although a melting test was performed on each of the 200 samples for each composition, no wetting defect was confirmed, and the wetting spread was improved and the wettability was improved from Examples 22 to 26.

  Next, die bonding was performed using each of the obtained samples, and the reliability of the bonded portion was evaluated. The evaluation method is specifically described below. Using the 1 mmφ sample and a die bonder, a dummy chip produced by vapor-depositing Au on the die bonding surface of a silicon chip was die-bonded to a copper lead frame. Next, this was molded with an epoxy resin. Using the molded product, the temperature cycle test of −50 ° C./150° C. was increased to 1000 cycles. Thereafter, the resin was opened and the bonded portion was observed by die bonding, and the case where no crack occurred in the chip and the bonded portion was evaluated as “good”, and the case where a crack occurred was evaluated as “bad”. The results are shown in Table 4.

  As shown in Table 4, with respect to Examples 27 to 36 that are within the scope of the present invention, the chip and the joint were not cracked by the above temperature cycle test, and the evaluation result of the joint reliability was “good”. "

  Next, a part of the molded product was mounted on a substrate at a reflow temperature of 260 ° C., and the presence or absence of abnormality in the chip and the joint after mounting was examined. As a result, no abnormality was observed, and no conspicuous voids could be confirmed.

  Moreover, evaluation of the heat resistance of the site | part joined with the solder alloy which concerns on this invention (Examples 27-36) is hold | maintained at 260 degreeC which is a reflow temperature for 10 second about 5 joined parts for each Example. However, it was confirmed that only a part was melted at any joint, and the whole was maintained without being melted. Therefore, the part joined by the solder alloy according to the present invention (Examples 27 to 36) does not cause peeling or voids even during reflow for mounting the electronic component on the substrate, and the characteristics of the electronic component are reduced. The problem is not expected to occur.

(Semiconductor package)
FIG. 1 is a cross-sectional view showing an example of a semiconductor package using a solder alloy according to the present invention. The semiconductor chip 1 is soldered to the lead frame island part 4 using the solder alloy 3 according to the present invention. The electrodes 2 on the semiconductor chip 1 are connected to the lead frame 5 via bonding wires 6. All of them are covered with the mold resin 7 except for the outer periphery of the lead frame 5.

It is sectional drawing which shows an example of a semiconductor package.

Explanation of symbols

1 Chip 2 Electrode 3 Solder Alloy 4 Lead Frame Island 5 Lead Frame 6 Bonding Wire 7 Mold Resin

Claims (6)

  Lead-free solder alloy characterized by containing Cu in excess of 10% by mass and 24.9% by mass or less, Sb in an amount of 5% by mass or more, the balance being Sn, and Sn content exceeding 70% by mass .  Cu exceeds 10% by mass and is 24.9% by mass or less, Sb is 5% by mass or more, Te is 0.01% by mass or more and 5% by mass or less, the balance is Sn, and the content of Sn is Lead-free solder alloy characterized by exceeding 70% by mass. Cu exceeds 10% by mass and is 24.9% by mass or less, Sb is 5% by mass or more, Te is 0.01% by mass to 5% by mass, and P is 0.001% by mass to 0.5% by mass. And the balance is Sn, and the Sn content exceeds 70% by mass. 5% by mass or more of Sb, 5% by mass or more of Cu, 0.1% by mass or more of Ag , the total content of Cu and Ag is more than 10% by mass and 24.9% by mass or less, and the balance is A lead-free solder alloy comprising Sn and having a Sn content exceeding 70% by mass. Sb is 5% by mass or more, Cu is 5% by mass or more, Te is 0.01% by mass to 5% by mass, Ag is 0.1% by mass or more, and the total content of Cu and Ag is 10% by mass. A lead-free solder alloy characterized by exceeding 24.9% by mass, the balance being Sn, and the Sn content exceeding 70% by mass. Sb 5 mass% or more, Cu 5 mass% or more, Te 0.01 mass% or more and 5 mass% or less, P 0.001 mass% or more and 0.5 mass% or less, Ag 0.1 mass% or more Lead-free, characterized in that the total content of Cu and Ag exceeds 10% by mass and is 24.9% by mass or less, the balance is Sn, and the Sn content exceeds 70% by mass Solder alloy.

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