JP2011005545A - Solder alloy, and soldered body using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new solder alloy capable of suppressing any secular change of the solder alloy while maintaining the characteristic of a Sn-Ag-Al solder alloy capable of soldering oxide such as glass and ceramic, and a hard-to-weld material such as Mo with poor wettability.SOLUTION: The solder alloy contains, by mass, 0.9-10.0% Ag, 0.01-0.50% Al, 0.04-3.00% Sb while the ratio Al/Sb is ≤0.25 (not including zero), and the balance Sn with inevitable impurities. The solder alloy may contain one or two kinds of ≤1.0% Y and ≤1.0% Ge.

Description

  The present invention belongs to a solder alloy suitable for joining a member having an oxide surface such as glass or ceramic or an oxide surface such as aluminum (Al), Mo having poor wettability, and the like and a solder joined body using the same. .

  Conventionally, in the joining technique of oxides such as glass, solder using lead or lead glass frit has been mainly used as a means for joining and sealing at around 380 ° C. However, the use of lead has become impossible due to environmental problems, and it has become necessary to establish alternative technologies. Therefore, the present inventors have proposed a solder alloy in which Ag and Al are added to Sn as a main component, as a solder alloy for joining oxide such as glass. (Patent Document 1) The present inventors have proposed a solder alloy in which Y and Ge are added to the oxide bonding solder alloy of Patent Document 1 in order to suppress voids during solder melting. (Patent Document 2)

WO2007 / 7840 US 2008/0241552

Since the Sn-Ag-Al solder alloys disclosed in Patent Documents 1 and 2 described above do not contain an element that forms an oxide (dross) such as Zn, there is an effect that handling at the time of soldering is easy. is there. However, according to the study by the present inventors, when the solder alloy proposed in Patent Document 1 or the like is held for a long time in the atmosphere where moisture exists, the interface between the solder and the material to be joined becomes discolored so that it becomes cloudy. I confirmed the new problem of going. Further, when examined in detail, it was also confirmed that the solder alloy itself was subject to voids (cavities) in the structure due to changes over time. Such modification of the solder alloy may deteriorate the bonding reliability.
In view of the above problems, an object of the present invention is to maintain the characteristics of an Sn—Ag—Al solder alloy capable of joining difficult-to-join materials such as oxides such as glass and ceramic, or Mo having poor wettability, and the like. It is to provide a new solder alloy that can suppress the change with time.

  The present inventors have studied the problem of aging of the solder that forms the joined body, and by adopting an alloy in which an appropriate amount of Sb is added to the Sn—Ag—Al solder alloy, the aging of the solder can be greatly improved. And reached the present invention.

That is, the present invention includes, in mass%, Ag: 0.9 to 10.0%, Al: 0.01 to 0.50%, Sb: 0.04 to 3.00%, and the ratio of Al / Sb. Is a solder alloy satisfying the relationship of 0.25 or less (not including 0) and comprising the remaining Sn and inevitable impurities.
The Al / Sb ratio is preferably 0.18 or less (excluding 0).
Moreover, it is preferable that the solder alloy of this invention contains any 1 type or 2 types of Y: 1.0% or less and Ge: 1.0% or less by the mass%.
Moreover, it is preferable that the solder alloy of this invention is Ag: 1.0-8.5%.
Moreover, it is preferable that the solder alloy of this invention is Al: 0.01-0.40%.
Moreover, it is preferable that the solder alloy of this invention is Al: 0.12-0.35%.
Moreover, it is preferable that the solder alloy of this invention is Sb: 0.50 to 3.00%.
Moreover, it is preferable that the solder alloy of this invention is Sb: 1.00-2.50%.
The solder alloy of the present invention is suitable for joining members having an oxide or oxide surface.
Moreover, the member which has an oxide or an oxidation surface can be firmly joined by the solder alloy of this invention, and an inexpensive solder joined body can be provided.

  According to the present invention, as a solder alloy applied to an airtight container such as a pair glass using glass or a display, or to fix a metal wiring on a glass substrate, the joint reliability can be dramatically improved. Therefore, its industrial value is extremely large.

It is a photograph which shows an example of the microstructure after the accelerated environment test of the solder alloy of this invention. It is a photograph which shows an example of the microstructure after the accelerated environment test of the solder alloy of a comparative example.

As described above, an important feature of the present invention is that an alloy obtained by adding an appropriate amount of Sb to a Sn—Ag—Al solder alloy is employed.
Hereinafter, the reason for limiting the component composition (mass%) of the solder alloy of the present invention will be described.

Sb: 0.04 to 3.00%
Sb is the most important element for suppressing the temporal change of the solder alloy of the present invention. Although it has not been accurately verified about the effect, Sb forms a compound with Al present in the Sn-Ag-Al solder alloy. As a result, oxidation progresses and causes the occurrence of white turbidity and voids. This is thought to be because the formation of the Ag-Al intermetallic compound is suppressed.
The Sb content depends on the Al content, but if it is too small, the effect of suppressing changes over time cannot be sufficiently exhibited, so 0.04% or more is necessary. Moreover, Sb improves the mechanical properties and thermal fatigue properties of the solder alloy such as tensile strength by dissolving in Sn. Therefore, 0.5% or more is preferable for the solder alloy of the present invention to obtain not only the effect of suppressing change with time but also sufficient mechanical properties and thermal fatigue properties. Moreover, it is more preferable to contain 1.00% or more.
On the other hand, even if Sb is added excessively, segregation of the Al—Sb compound increases, and the effect of suppressing the change with time obtained by addition of Sb cannot be sufficiently obtained. In addition, when the hard and brittle Al—Sb compound is excessively present in the solder, not only the initial mechanical properties are lowered, but also the oxidation of the Al—Sb compound itself can suppress the change over time of the solder alloy. It is considered to have an adverse effect. Furthermore, the increase in the Sb content decreases the solderability as the wettability deteriorates in addition to the increase in the melting point of the solder alloy.
Therefore, in the present invention, the maximum Sb content is 3.00% or less. Preferably it is 2.50% or less.

Ag: 0.9 to 10.0%
The Sn—Ag based solder alloy, which is the base alloy of the solder alloy of the present invention, determines basic characteristics such as the creep strength and ductility of the solder in addition to the effect of lowering the melting point due to the eutectic reaction. In particular, the Ag content greatly affects the creep strength. Even in the solder alloy of the present invention, if the amount of Ag is too small, an extreme decrease in creep strength can be considered. Therefore, the Ag content of the solder alloy of the present invention needs to be 0.9% or more in order to ensure the strength necessary for joining.
On the other hand, if the content of Ag is too large, in addition to an increase in the melting point, a hard and brittle coarse Sn-Ag intermetallic compound is generated in the solder alloy, which causes a drop impact resistance characteristic to be lowered. Therefore, the content of Ag in the solder alloy of the present invention is 10.0% or less, and more preferably 8.5% or less. In addition, it is preferable that the drop impact resistance characteristics such as a cellular phone are 5.0% or less.
Moreover, Ag improves the thermal fatigue characteristics and mechanical characteristics of the solder alloy when an intermetallic compound with Al is formed.
Therefore, the content of Ag in the solder alloy of the present invention is 0.9 to 10.0%, and more preferably 1.0 to 8.5%.

Al: 0.01 to 0.50%
Al is an essential metal that is essential for the Sn—Ag-based solder alloy of the present invention to achieve bonding with difficult-to-bond materials such as glass. That is, in a Sn-Ag based solder alloy, it is difficult to join difficult-to-join materials even if the Sn and Ag composition is changed. However, the addition of Al improves wettability with difficult-to-join materials. Adhesion with difficult-to-join materials becomes possible. This is because Al tends to be an oxide and easily binds to the oxide of the material to be joined. As a result, the wettability with respect to the difficult-to-join material is improved.
However, if the Al content is too high, the Al excessively forms an oxide, which in turn reduces the bondability or forms an Ag-Al intermetallic compound in which oxidation tends to proceed. -There is a concern that the solder joint, which is thought to be caused by oxidation or the like from the interface of the material to be joined, is likely to become clouded.
Therefore, the Al content of the present invention is set to 0.01 to 0.50% in relation to the Sb content described above. Preferably, it is 0.01-0.40%, More preferably, it is 0.12-0.35%.

Al / Sb content ratio: 0.25 or less (excluding 0)
An important feature of the present invention is that the content ratio of Al and Sb contained in the solder alloy is optimized. The reason will be described in detail below.
As described above, Al in the Sn—Ag—Al solder alloy not containing Sb forms an Ag—Al intermetallic compound that is an intermetallic compound with Ag. This Ag-Al intermetallic compound causes white turbidity in the solder joint, which is thought to be caused by oxidation or the like from the interface of the solder alloy and the solder alloy / bonded material, and therefore it is necessary to suppress the precipitation of the Ag-Al intermetallic compound. There is. Therefore, the solder alloy of the present invention suppresses the precipitation of the easily oxidizable Ag-Al intermetallic compound by positively precipitating the Al-Sb compound by adding Sb to the Sn-Ag-Al solder alloy. Thus, the effect of suppressing the white turbidity of the solder joint is obtained.
However, the oxidation of the solder alloy cannot be sufficiently suppressed only by adding the above-described Al or Sb. The reason is that when the Al content in the solder alloy is too high or the Sb content is too low, the Ag-Al intermetallic compound is excessively precipitated in the solder alloy. In such a state, it becomes difficult to suppress the cloudiness of the solder joint.
Therefore, in the present invention, in order to obtain a sufficient oxidation suppression effect, the ratio of Al / Sb contained in the solder alloy is set to 0.25 or less (not including 0). Furthermore, in order to obtain sufficient suppression of change with time, it is preferably 0.08 or less.

Remaining Sn and inevitable impurities Sn is a base element constituting the solder alloy of the present invention that acts to relax the thermal expansion coefficient with the material to be joined such as glass and lower the melting temperature. In particular, in adjusting the thermal expansion coefficient, Sn is desirably blended in the range of 85 to 95%. More preferably, it is 90 to 95%.
As unavoidable impurities, Fe, Ni, Co, Cr, V, and Mn inhibit the wettability of the solder, and thus these elements are preferably regulated to 1% or less in total. More preferably, the total amount is 500 ppm or less.

Moreover, since Ga, P, and B cause a void generation at the time of melting the solder, it is preferable to limit these elements to 500 ppm or less. More preferably, it is 100 ppm or less.
In addition, in the Sn-based solder, Zn is oxidized near the solder surface, so that micro cracks are developed in the solder, and the internal Zn is also gradually oxidized, and the solder becomes brittle. In addition, Zn has a high vapor pressure, and when it is melted under vacuum and soldered, Zn metal fume is generated, which contaminates the material to be joined and causes contamination in the vacuum furnace. In addition, the addition of Zn increases the amount of dross generated during soldering, which tends to hinder solder bonding. In particular, the ultrasonic soldering method used for solder joining tends to be noticeable because of cavitation. Therefore, in the solder alloy of the present invention, Zn is preferably excluded as much as possible, and preferably 100 ppm or less.

  Oxygen in the solder alloy increases the amount of oxide (dross) generated during soldering, and further causes the oxidation of the Al—Sb compound, making the solder brittle. Therefore, the oxygen value of the solder alloy of the present invention is preferably 500 ppm or less, and more preferably 50 ppm or less.

Y: 1.0% or less Y can also be contained in the solder alloy of the present invention. Y is optimal for reducing the generation of voids during melting of the solder, and is effective when it includes a step of remelting the solder joint. Although it is not clear about the action of void suppression at the time of specific solder melting of Y, it is expected that the surface tension of the molten metal is lowered and gas entrainment is reduced.
However, if a large amount of Y is contained, voids are generated when the solder is melted. This is thought to be due to the increase in the viscosity of the solder itself due to the formation of an intermetallic compound with Al, but the mechanism is not clear. Therefore, the Y content in the solder alloy of the present invention should be kept to a minimum. Therefore, in the present invention, the amount of Y is 1.0% or less, preferably 0.1% or less in terms of mass%. In order to clearly obtain the effect of adding Y, 0.01% or more is preferable.

Ge: 1.0% or less The solder alloy of the present invention may contain Ge. Since Ge suppresses the amount of oxide (dross) generated during melting, it can prevent entrainment of solder oxide and the like, and can perform bonding with higher reliability.
However, when a large amount of Ge is contained, the adhesion with the material to be joined is also affected by the Ge oxide generated on the solder surface layer portion as the amount of oxide of Ge itself increases rather than the effect of suppressing surface oxidation. Therefore, in the present invention, the Ge amount is preferably 0.50% or less by mass%. More preferably, 0.05% or less is more preferable. In order to clearly obtain the effect of Ge addition, 0.01% or more is preferable.

Even if the solder alloy of the present invention is a difficult-to-join material, it can be joined without applying a flux to the joint surface, and the temporal change of the solder after joining the joining objects can be suppressed. In addition to oxides such as ceramics such as alumina and soda lime glass, it is possible to suppress changes over time while exhibiting excellent bonding ability to members having an oxidized surface such as Al. . In addition, a change with time can be suppressed even for a nitride such as aluminum nitride.
Furthermore, the solder alloy of the present invention is suitable not only for the oxides and nitrides described above, but also for those in which a thin film such as Mo or Al is formed on glass.

In addition, the solder alloy of the present invention is not limited to the above-mentioned joining. For example, the solder alloy of the present invention applies a flux to the joint surface even for various kinds of metals such as stainless steel, copper, and Fe-Ni alloys. Even if it is a mating material that has a bonding ability and is inferior in bonding ability, it can be used after being subjected to surface treatment for imparting the bonding ability.
Moreover, the solder alloy of the present invention can be used as an alternative to the grounding treatment of soldering by applying to the oxide / nitride surface.

  For joining with difficult-to-join materials such as oxides and nitrides using the solder alloy of the present invention, for example, for fixing metal wiring on a glass substrate, a molten solder is applied on a glass substrate at room temperature. It becomes possible. Also, for sealing hermetic containers such as paired glass and displays, the member to be joined is heated to a temperature higher than the liquidus temperature of the solder alloy, or the heat capacity of the material to be joined is taken into account. It is possible to preheat the material to be joined below the liquidus temperature of the solder alloy. In addition, it is effective to apply ultrasonic vibration to the solder alloy in the above-mentioned bonding to the difficult-to-bond material, and oxygen is taken into the molten solder to promote the wetting of the material to be bonded and contribute to the bonding.

  Sn, Ag, Al, Sb, Y and Ge were weighed so as to have the composition shown in Table 1, and then melted. The molten alloy obtained in pairs was poured into a mold to produce a solder alloy, and the following evaluation test was performed. went.

(Evaluation Test 1)
As a material to be joined, a borosilicate glass plate (product name TEMPAX) cut to 30 mm square and 3 mm thick was placed on a hot plate heated to 350 ° C. and heated in advance. After that, using a soldering iron (ultrasonic soldering device SUNBUNDER USM-III, manufactured by Kuroda Techno Co., Ltd.) to which ultrasonic vibration is applied, the solder alloy is applied to the entire surface of the glass plate so that the thickness becomes 100 μm. Slowly cooled. Next, the sample was cooled to room temperature, and the solder surface of the sample was cut with a cutter so as to form a 5 × 5 grid of 5 mm square lattices, thereby producing a peel test piece.
In order to confirm the change in the bonding strength of the solder, the specimen was left for 1000 hours in a high-temperature and high-humidity tester (HIFLEX manufactured by Enomoto Kasei Co., Ltd.) at 85 ° C. and 85 RH% as an accelerated environmental test.

Next, a peel test was performed on the solder / glass plate connection interface of the test piece before and after the accelerated environment test. In the test, an adhesive tape (CT-405AP-24 manufactured by Nichiban Co., Ltd.) was attached to one surface of the test piece, a three-time peeling test was performed, and the areas where the solder was peeled were counted. Note that the peel test was performed on the 3 × 3 squares in the center of the 5 × 5 squares in order to ignore the influence of the edge portion.
As shown in Table 1, before the accelerated environment test, it was confirmed that both of the solder alloys of the present invention example and the comparative example had sufficient strength without peeling. Similarly, after the accelerated environment test, among the nine target masses, the solder alloys of the present invention example and the comparative example had the solder peeled only in the region of 1 mass or less. From this, it was confirmed that the solder alloy of the example of the present invention has sufficient bonding strength even after the accelerated environmental test.

(Evaluation test 2)
As a material to be joined, a borosilicate glass plate (product name TEMPAX) cut to 30 mm square and 3 mm thick was placed on a hot plate heated to 350 ° C. and heated in advance. After that, using a soldering iron (ultrasonic soldering device SUNBUNDER USM-III, manufactured by Kuroda Techno Co., Ltd.) to which ultrasonic vibration is applied, the solder alloy is applied to the entire surface of the glass plate so that the thickness becomes 100 μm. Slowly cooled.
In order to confirm the effect of suppressing white turbidity at the solder joints, which are thought to be caused by oxidation from the solder alloy / glass plate interface, etc., as an accelerated environment test, a high-temperature and high-humidity tester at 85 ° C and 85RH% (Enomoto Kasei Co., Ltd.) The test piece was left for 1000 hours in HIFLEX.

The cloudiness region of the solder joint of the test piece after the accelerated environment test was evaluated. The white turbidity region of the solder joint was evaluated by observing the solder / glass plate joint interface of the test piece from the glass side, measuring the white turbid area with respect to the entire 30 mm square glass plate, and evaluating the area ratio.
As shown in Table 1, the white turbid area ratio of the solder joint portion of the present invention example was 8% or less, whereas the white turbid area ratio of the comparative example was a value exceeding 80%. From this, it has confirmed that the solder alloy of this invention can suppress the cloudiness of a solder joint part even after an accelerated environment test by making the content rate of Al / Sb into 0.25 or less.

(Evaluation Test 3)
The sample used was a solder wire obtained by processing a solder alloy produced to have the composition shown in Table 1 into a wire of φ1 mm. In order to evaluate the oxidation resistance of the solder alloy, it was left as an accelerated environment test for 1000 hours in a high-temperature and high-humidity tester (HIFLEX manufactured by Enomoto Kasei Co., Ltd.) at 85 ° C. and 85 RH%.

The oxygen value of the solder alloy is measured with EMGA-620W manufactured by HORIBA, Ltd. when the oxygen value of the solder alloy is 1000 ppm or less, and when the oxygen value of the solder alloy exceeds 1000 ppm, And measured.
As shown in Table 1, after the accelerated environment test, the oxygen value of the solder alloy of the example of the present invention was 300 ppm or less, whereas the oxygen value of the solder alloy of the comparative example was a value exceeding 1000 ppm. From this, the solder alloy of this invention example has confirmed the effect which suppresses the oxidation of a solder alloy by making the content rate of Al / Sb into 0.25 or less.

(Evaluation Test 4)
As the sample, a solder wire obtained by processing a solder alloy produced in the same manner as in the evaluation test 3 into a wire of φ1 mm was used. In order to evaluate deterioration due to aging of the solder alloy, it was left as an accelerated environment test for 1000 hours in a high-temperature and high-humidity tester (HIFLEX manufactured by Enomoto Kasei Co., Ltd.) at 85 ° C. and 85 RH%.

In order to investigate the deterioration of the solder alloy due to aging, a 90 ° bending test was performed on the solder wire after the accelerated environmental test.
As shown in Table 1, in the solder alloy of the example of the present invention, the solder wire did not break even when the 90 ° bending test was performed nine times or more, but in the solder alloy of the comparative example, it was 90 ° once. The solder wire was broken by bending. From this, it was confirmed that the solder alloy of the example of the present invention suppresses deterioration due to aging of the solder alloy by setting the content ratio of Al / Sb to 0.25 or less.

  In mass%, Ag = 8.5%, Al = 0.35%, Sb = 2.0%, Y = 0.075%, Ge = 0.03%, the composition of the balance Sn (Al / Sb = 0. 18) After being weighed so as to become 18), melting was performed in an Ar atmosphere, and then the obtained molten alloy was poured into a mold to produce the solder alloy of the present invention. Similarly, as a comparative example, without adding Sb, the same solder alloy of mass%, Ag = 8.5%, Al = 0.35%, Y = 0.075%, Ge = 0.03%, and remaining Sn It was prepared. The following evaluation test was performed on the produced solder alloy.

(Evaluation Test 1)
First, a borosilicate glass plate (product name TEMPAX) cut into a 50 mm square and a thickness of 3 mm as a material to be joined was placed on a hot plate heated to 350 ° C. and heated in advance. Thereafter, using a soldering iron (ultrasonic soldering apparatus SUNBUNDER USM-III manufactured by Kuroda Techno Co., Ltd.) to which ultrasonic vibration is applied, the glass plate is formed so that the thickness of the solder alloy of the present invention and the solder alloy of the comparative example becomes 50 μm. It was applied on one side and slowly cooled in the atmosphere. After cooling to room temperature, the applied solder surface was cut with a cutter so as to form a 5 × 5 grid of 5 mm square grids, thereby preparing a test piece.
In order to confirm the effect of suppressing the oxidation of solder, as an accelerated environment test, the test piece was left for 168 hours in a high-temperature and high-humidity tester (HIFLEX manufactured by Enomoto Kasei Co., Ltd.) at 85 ° C. and 85 RH%.

The solder / glass plate bonding interface of the test piece before and after the accelerated environment test was observed from the glass side. In addition, in order to ignore the influence of the edge portion among the 5 × 5 cells, the observation was performed on the 3 × 3 cells at the center.
As a result, it was confirmed that both the solder alloy of the present invention and the solder alloy of the comparative example were in close contact with the glass immediately after application and a mirror surface was obtained, but after the accelerated environment test, the solder alloy of the present invention was confirmed. Then, while only a small part (a part of three of the target nine squares) remained cloudy, in the solder alloy of the comparative example, white turbidity was observed throughout the nine squares. From this result, it was confirmed that the solder alloy of the present invention to which Sb was added was effective in suppressing white turbidity in a high temperature and high humidity environment.

(Evaluation test 2)
Similarly to the evaluation test 1, a test piece coated with the solder alloy of the present invention and the solder alloy of the comparative example was prepared. Next, a peel test was performed on the solder / glass plate connection interface of the test piece before and after the accelerated environment test. In the peel test, an adhesive tape (CT-405AP-24 manufactured by Nichiban Co., Ltd.) was attached to one surface of the test piece, and peeling was repeated three times to count the areas where the solder was peeled off.
Immediately after the solder application, peeling of the solder alloy of the present invention and the solder alloy of the comparative example could not be confirmed.
After the accelerated environment test, solder peeling occurred only in the area of 1 square in the subject example of the 9 squares of the object, whereas in the comparative example, solder peeling occurred in the area of 5 squares. From this result, it was confirmed that the solder alloy of the present invention to which Sb was added was effective in preventing the deterioration of the bonding strength with time in a high temperature and high humidity environment.

(Evaluation Test 3)
Similar to test evaluation 1, the solder alloy of the present invention and the solder alloy of the comparative example were produced and then rolled into a solder sheet having a thickness of 0.35 mm, and an accelerated environment test similar to (Evaluation test 1) was performed. Changes in the internal structure of the solder were observed.
FIG. 1 shows the microstructure after the accelerated environment test of the solder alloy of the present invention, and FIG. 2 shows the microstructure after the accelerated environment test of the solder alloy of the comparative example. As is clear from comparison between FIG. 1 and FIG. 2, voids inside the solder alloy that are not confirmed in the solder alloy of the present invention are confirmed in the solder alloy of the comparative example.
The generation of voids in the solder alloy is a big problem for applications that require airtightness at the joint, and the solder alloy of the present invention to which Sb is added is effective for suppressing the occurrence of this problem. I was able to confirm.

  After being weighed so that the composition of Ag = 3.5%, Al = 0.10%, Sb = 1.5%, and remaining Sn (Al / Sb = 0.07) in mass%, in an Ar atmosphere After melting, the resulting molten alloy was poured into a mold to produce the solder alloy of the present invention. The following evaluation test was performed on the produced solder alloy.

(Evaluation Test 1)
As a material to be joined, an alumina plate (product name SSA-S manufactured by Nikkato Co., Ltd.) cut to a 25 mm square and a thickness of 2.5 mm was placed on a hot plate heated to 270 ° C. and heated in advance. Then, using a soldering iron (ultrasonic soldering device SUNBUNDER USM-III manufactured by Kuroda Techno Co., Ltd.) to which ultrasonic vibration was applied, the solder alloy of the present invention was applied to one surface of the alumina plate so that the thickness became 130 μm, and the atmosphere Slow cooling in. After cooling to room temperature, the applied solder surface was cut with a cutter so as to form a 5 × 5 grid of 5 mm square grids, to produce a peel test piece.

The test piece was a 3 × 3 square in the center portion in order to ignore the influence of the edge portion among the 5 × 5 squares.
As a result of the peel test, peeling of the solder alloy of the present invention applied on the alumina substrate was not confirmed. From this result, it was confirmed that the solder alloy of the present invention to which Sb was added had a sufficient bonding strength even for an alumina member having an oxidized surface.

(Evaluation test 2)
A 25 mm square and 0.7 mm thick glass substrate on which a 0.3 μm thick Mo film was formed as a material to be joined was placed on a hot plate heated to 280 ° C. and heated in advance. Thereafter, using a soldering iron (ultrasonic soldering apparatus SUNBUNDER USM-III manufactured by Kuroda Techno Co., Ltd.) to which ultrasonic vibration was applied, the Mo film of the glass substrate was formed so that the thickness of the solder alloy of the present invention was 130 μm. It was applied to one side and slowly cooled in the atmosphere. After cooling to room temperature, the applied solder surface was cut with a cutter so as to form a 5 × 5 grid of 5 mm square grids, to produce a peel test piece.

The test piece was a 3 × 3 square in the center portion in order to ignore the influence of the edge portion among the 5 × 5 squares.
As a result of the peel test, peeling of the solder alloy of the present invention applied to the Mo film was not confirmed. From this result, it was confirmed that the solder alloy of the present invention to which Sb was added had a sufficient bonding strength even for difficult-to-bond materials such as Mo.

(Evaluation Test 3)
As a material to be joined, a 30 mm square and 1.0 mm thick Al plate was placed on a hot plate heated to 240 ° C. and heated in advance. After that, using a soldering iron (ultrasonic soldering device SUNBUNDER USM-III manufactured by Kuroda Techno Co., Ltd.) to which ultrasonic vibration is applied, the solder alloy of the present invention is applied to the entire surface of the Al plate so that the thickness becomes 100 μm. Slow cooling in. After cooling to room temperature, the applied solder surface was cut with a cutter so as to form a 5 × 5 grid of 5 mm square grids, to produce a peel test piece.

The test piece was a 3 × 3 square in the center portion in order to ignore the influence of the edge portion among the 5 × 5 squares.
As a result of the peel test, peeling of the solder alloy of the present invention applied to the Al plate was not confirmed. From this result, it was confirmed that the solder alloy of the present invention to which Sb was added had sufficient bonding strength even for an Al member having an oxidized surface.

Claims (10)

  In mass%, Ag: 0.9 to 10.0%, Al: 0.01 to 0.50%, Sb: 0.04 to 3.00%, and the ratio of Al / Sb is 0.25 or less A solder alloy characterized by comprising the remaining Sn and inevitable impurities.   The solder alloy according to claim 1, wherein the Al / Sb ratio is 0.18 or less (not including 0).   The solder alloy according to claim 1 or 2, wherein Ag: 1.0 to 8.5% by mass.   The solder alloy according to any one of claims 1 to 3, wherein Al is 0.01 to 0.40% by mass.   4. The solder alloy according to claim 1, wherein Al is 0.12 to 0.35% by mass.   The solder alloy according to any one of claims 1 to 5, wherein Sb is 0.50 to 3.00% in terms of mass%.   The solder alloy according to any one of claims 1 to 5, wherein Sb is 1.00 to 2.50% in terms of mass%.   8. The solder alloy according to claim 1, wherein the solder alloy contains at least one of Y: 1.0% or less and Ge: 1.0% or less.   The solder alloy according to any one of claims 1 to 8, wherein a member having an oxide or an oxidized surface is joined. 9. A solder joint comprising a member having an oxide or oxide surface joined to the solder alloy according to claim 1.