• 专利附录
  • 专利说明
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    • 专利摘要:
    LEAD-FREE WELDING ALLOY. It is a lead free solder and solder alloy with the ability to maintain strong junction resistibility even in a high temperature state after soldering and which has high reliability and versatility. The lead-free solder alloy composition of the present invention has Sn-Cu-Ni as a basic composition, which includes 0.1 to 2.0% by weight of Cu, and 0.01 to 0.5% by weight of Ni, 0.1 to 5% by mass of Bi, and 76.0 to 99.5% by mass of Sn, so that it is possible to implement welding with high reliability without decreasing the joint resistibility of a welded joint even in a state in which it is exposed to elevated temperature for a long time, as well as the junction resistibility at the time of bonding.
    公开号:BR112016024855B1
    申请号:R112016024855-4
    申请日:2015-04-28
    公开日:2021-05-04
    发明作者:Tetsuro Nishimura；Takatoshi Nishimura
    申请人:Nihon Superior Co., Ltd；
    IPC主号:
    专利说明:

    FIELD OF TECHNIQUE
    [0001] The present invention relates to a lead-free solder alloy that has less deterioration over time and excellent long-term reliability, and a solder joint using the solder alloy. DESCRIPTION OF RELATED TECHNIQUE
    [0002] In order to reduce the overall environmental burden, a lead-free solder has been widely distributed as a bonding material for electronic components, and a Sn-Ag-Cu system solder alloy or a system solder alloy of Sn-Cu-Ni is a representative composition of them.
    [0003] Recently, in addition to the Sn-Ag-Cu system solder alloy and the Sn-Cu-Ni system solder alloy, a lead-free solder alloy in which Bi, In or Sb, etc. is added and a lead-free solder alloy, such as a Sn-Zn solder alloy, according to the soldering purpose and soldering characteristics, has been proposed.
    [0004] In particular, lead-free solder alloy in which Bi, Sb or In is added for the purpose of increasing the mechanical strength of soldered joints or decreasing the temperature of solids, is disclosed.
    [0005] For example, Patent Document 1 discloses a lead-free solder alloy that allows the melting point of solder to be easily controlled by adding 0.01 to 3% by weight of Bi to a basic composition of Sn -Cu-Ni.
    [0006] Furthermore, Patent Document 2 discloses a lead-free solder alloy that has improved mechanical resistibility by adding Bi to a basic composition of Sn-Cu-Sb in a proportion of 1% by weight or less.
    [0007] Additionally, Patent Document 3 discloses a lead-free solder alloy that has effects of increasing adhesive resistibility and lowering the temperature of solids by adding 0.001 to 5% by weight of Cu, Ni and Bi to the No.
    [0008] Additionally, the applicant discloses, in Patent Document 4, a lead-free solder alloy that exhibits strong joint resistability at the time of soldering, forming an intermetallic compound that has a closed hexagonal grouped structure in a joint welded and its junction interface, adding a prescribed amount of Ni and Cu to a eutectic composition of Sn-Bi.
    [0009] However, the techniques revealed in Patent Documents 1 to 4 also have problems to be solved. For example, the solder alloy composition disclosed in Patent Document 1 requires 2 to 5% by weight Cu mixture amount, and a soldering temperature that exceeds 400°C which is a temperature of at least 150°C higher than that of the Sn-Ag-Cu system solder alloy or the Sn-Cu-Ni system solder alloy which is a representative lead-free solder composition.
    [0010] Additionally, in a solder alloy composition disclosed in Patent Document 2, 10% by weight or more of Sb is mixed with the base composition thereof so that the solids temperature is 230°C or greater as described in the example, and as described in Patent Document 1, it is necessary to carry out a soldering process at a higher temperature as compared to a conventional representative lead-free solder composition.
    [0011] Additionally, the technique disclosed in Patent Document 3 is not a solder alloy composition with the ability to be applied to various solder connections, but a solder alloy composition limited to super fine wire solder and , therefore, has problems regarding versatility.
    [0012] However, the technique disclosed in Patent Document 4 is a technique with the purpose of providing strong junction by forming an intermetallic compound that has a NiAs-type crystal structure at a junction interface, in which a ratio of mixture of Sn and Bi is Sn: Bi = 76 to 37% atomic weight: 23 to 63% atomic weight, and the technique is aimed at a composition close to eutectic.
    [0013] Furthermore, Patent Publication Document 5 discloses a technique relating to a solder alloy composition which is adapted to prevent an occurrence of tin pest at an extremely low temperature, and includes Sn-Cu-Ni-Bi which It has good wettability and impact resistance. For the purpose of the corresponding invention, the composition has numerical values limited to a range where a mixing amount of Cu is 0.5 to 0.8% by mass, the mixing amount of Ni is 0.02 to 0 .04% by mass, and the mixing amount of Bi is 0.1% by mass or more and less than 1% by mass.
    [0014] In general, when an electronic device is being used, a soldered joint of the electronic device is in a conductive state and, in some cases, the solder bonding part may be exposed to elevated temperature.
    [0015] In the present document, in terms of solder bonding reliability, a bonding resistibility when the solder bonding part is exposed to high temperature becomes very important, as well as bonding resistibility at the time of soldering.
    [0016] However, the techniques disclosed in Patent Documents 1 to 5 do not teach any content regarding bond strength when the weld joint is exposed to elevated temperature for a long time.
    [0017] Additionally, a lead-free solder alloy that enables soldering with high reliability that is sufficient to withstand the long-term use of the electronic device, and that has versatility regarding solder bonding is required. RELATED TECHNIQUE DOCUMENT PATENT DOCUMENT
    [0018] [Patent Document 1] Patent Publication open to Public inspection in JP 2001-334384
    [0019] [Patent Document 2] Patent Publication open to Public inspection in JP 2004-298931
    [0020] [Patent Document 3] Patent Publication open to Public inspection in JP 2006-255762
    [0021] [Patent Document 4] Patent Publication open to Public inspection in JP 2013-744
    [0022] [Patent Document 5] Publication 2009/131114 SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION
    [0023] An objective of the present invention is to provide a lead-free solder alloy and a soldered joint with the ability to maintain strong joint resistibility without reducing bond resistibility even in a high temperature state after soldering, and which has high reliability and versatility. MEANS TO SOLVE PROBLEMS
    [0024] The present inventors have focused on a lead-free solder alloy composition and an intermetallic compound, and have repeatedly conducted intensive studies for the above-described objective. As a result, they found that by adding a specific amount of Bi to a lead-free solder alloy that has Sn-Cu-Ni as a basic composition, a decrease in bond strength is suppressed even when a part of solder bonding is exposed to elevated temperature and thus the present invention has been completed based on the above finding.
    [0025] That is, the present invention provides the lead-free solder alloy composition that has Sn-Cu-Ni as a basic composition, which includes 76.0 to 99.5% by mass of Sn, 0.1 to 2.0% by mass of Cu, and 0.01 to 0.5% by mass of Ni, and additionally including 0.1 to 5.0% by mass of Bi, thus enabling welding with high reliability that maintains the joining resistibility without decreasing the bonding resistibility of a welded joint even when it is exposed to high temperature for a long time, as well as at the time of bonding. ADVANTAGEOUS EFFECTS
    [0026] The lead-free solder alloy according to the present invention has versatility that is not limited by a method of using a solder product or a shape thereof, and even when the solder joint is exposed to a state of elevated temperature for a long time, the junction resistibility will not decrease. Therefore, lead-free solder alloy can be widely applied to a device that has a solder connection part in which high current flows, a device that is exposed to a state of high temperature, or the like, as well as the junction of an electronic device. BRIEF DESCRIPTION OF THE DRAWINGS
    [0027] Figure 1 is a graph that illustrates an experimental result.
    [0028] Figure 2 is a graph that summarizes the results of measuring the tensile strength of each sample that has a composition of Table 2.
    [0029] Figure 3 is a graph that summarizes the results of measuring the tensile strength of each sample that has a composition of Table 4.
    [0030] Figure 4 is a graph summarizing the results of measuring the tensile strength of samples having different additional amounts of Cu.
    [0031] Figure 5 is a graph summarizing the results of measuring the tensile strength of samples that have different additional amounts of Ni.
    [0032] Figure 6 is a graph summarizing the results of measuring the tensile strength of samples that have different additional amounts of Ge.
    [0033] Figure 7 is a graph summarizing the results of measuring the tensile strength of samples that have different additional amounts of In.
    [0034] Figure 8 is a graph summarizing the elongation rate measurement results of the modified In samples.
    [0035] Figure 9 is a graph summarizing the results of measuring the tensile strength of samples in which an additional element is added. WAYS TO PERFORM THE INVENTION
    [0036] Hereinafter, the present invention will be described in detail.
    [0037] Conventionally, the junction resistibility at the time of welding has been an important item for the welding of electronic devices, or the like, and the welding alloy with the ability to improve the junction resistibility at the time of welding has been developed and provided.
    [0038] However, welded joints used in electronic or similar devices can often be exposed to elevated temperature or in a state in which current flows, especially during use of the electronic device and, in some cases, an increase in the temperature of the joints soldered can be accelerated by the external environment. Therefore, in order to improve the reliability of welded joints, it is required to suppress deterioration over time of welded joints that are exposed to an elevated temperature state.
    [0039] However, according to a method for evaluating welded joints, a method to use a test referred to as a thermal cycling test in which a welded joint is repeatedly left in a high temperature state and a low temperature state by a prescribed time is generally used. However, it is also known that, in the method, since the welded joints are left in a high temperature state and then left in a low temperature state for a prescribed time, a condition of the welded joints after the test is different from that of an aging test in which the soldered joints are only left in an elevated temperature state for a long time.
    [0040] The present invention relates to a solder alloy composition with the ability to suppress a decrease in the joint resistance of a soldered joint due to continuously exposing the soldered joints in a state of high temperature, i.e., an environment that is an example of a situation according to the real state of using electronic devices.
    [0041] In particular, the present invention relates to a lead-free solder alloy which may include 76.0 to 99.5% by mass of Sn, 0.1 to 2.0% by mass of Cu, 0, 01 to 0.5% by mass of Ni, and 0.1 to 5.0% by mass of Bi, and a welded joint using lead-free solder alloy.
    [0042] Additionally, it is also possible to add one or two or more elements selected from 0.1 to 5.0% by mass of Sb, 0.1 to 10.0% by mass of In, 0.001 to 1.0 % by mass of Ge, and 0.001 to 1.0% by mass of Ga to a basic composition that includes 76.0 to 99.5% by mass of Sn, 0.1 to 2.0% by mass of Cu, 0 .01 to 0.5% by mass of Ni, and 0.1 to 5.0% by mass of Bi.
    [0043] Furthermore, an element such as P, Co, Al, Ti, Ag, etc. can also be arbitrarily added to the lead-free solder alloy which has Sn-Cu-Ni-Bi as the basic composition thereof of the present invention, in a range in which the effects of the present invention are obtained.
    [0044] A synergy effect of increasing the mechanical strength of the weld joints is expected while achieving the effects of the present invention by adding Sb to a solder alloy that has Sn-Cu-Ni-Bi as the basic composition of the same.
    [0045] Additionally, when adding In, even if Cu or Sb are mixed into a solder alloy in an amount exceeding 1% by mass, an effect of lowering the solids temperature can be obtained while achieving the effects of present invention, and an effect of decreasing a load applied to electronic components attached to electronic devices, welding work, or the like can be expected.
    [0046] Additionally, when adding Ge or Ga, it is possible to suppress the oxidation of the weld joint and improve the wettability, and a synergy effect of improving the long-term reliability and welding characteristics of the weld joint can also be expected, while achieving the effects of the present invention.
    [0047] In the following, the effects of the present invention will be described by illustrating an experimental example.
    [0048] An aging test to be described below was carried out on the lead-free solder alloy of the present invention and its properties were evaluated. AGING TEST (METHOD)
    [0049] 1) a solder alloy having a composition shown in Table 1 was prepared and melted and then cast in a canine bone-shaped mold that has a cross-section of 10 mm x 10 mm, preparing, thus, a sample for measurement.
    [0050] 2) The measurement sample was left at 150°C for 500 hours to perform the aging processing.
    [0051] 3) Samples in which aging processing has been performed and samples in which aging processing has not been performed are pushed until they are cut using a testing machine, AG-IS (manufactured by Shimadzu Corp.) under a condition of 10 mm/min at room temperature (20°C to 25°C), thus measuring the tensile strength of the samples. (RESULT)
    [0052] The measured results are illustrated in Figure 1. TABLE 1

    [0053] The graph illustrated in Figure 1 illustrates the measurement results of the samples in which the aging processing was not performed on the left side, and the measurement results of the samples in which the aging processing was performed on the right side , respectively.
    [0054] The samples of the present invention correspond to Nos. 2 to 5, and it can be understood that the tensile strength of the sample in which the aging processing was carried out is not much decreased as compared to that of the sample in which the aging processing has not was performed.
    [0055] Meanwhile, sample #1 and samples #6 to 9 which are comparative samples show a notable decrease in the tensile strength of the sample in which the aging processing was performed as compared to the sample in which the aging processing did not was performed.
    [0056] From the results, it could be clearly seen that even though the lead-free solder alloy which has Sn-Cu-Ni-Bi as the basic composition of the present invention has been exposed to the elevated temperature of 150°C by 500 hours, the decrease in tensile strength thereof was suppressed as compared to other lead-free solder alloy compositions.
    [0057] Hereinafter, in relation to the basic composition of Sn-Cu-Ni-Bi, a change in tensile strength that results from a change in an additional amount of Bi will be described in detail. In more detail, it will be described based on the measurement result of a change in the tensile strength of the samples wherein 0% by mass to 6% by mass of Bi is added to such a composition.
    [0058] Table 2 is a composition table that shows the compositions of the samples used in measuring tensile strength.
    [0059] According to a Comparative Example (Sample i: Sample name is SN2), a composition of Sn-Cu-Ni to which Bi is not mixed is contained. Additionally, samples that include Bi are referred to as Sample ii "Sample name: +0.1Bi*", Sample iii "Sample name: +0.5Bi*", Sample iv "Sample name: +1.0Bi* ", Sample v "Sample name: +1.5Bi*", Sample vi "Sample name: +2.0Bi*", Sample vii "Sample name: +3.0Bi*", Sample viii "Sample name : +4.0Bi*", Sample ix "Sample name: +5.0Bi*", and Sample x "Sample name: +6.0Bi*". In the iax samples, Bi is included in an amount of 0.1% by mass, 0.5% by mass, 1.0% by mass, 1.5% by mass, 2.0% by mass, 3.0% by mass, 4.0% by mass, 5.0% by mass, and 6.0% by mass, respectively.
    [0060] The iax samples having the compositions in Table 2 were prepared by the method described above in paragraph [0016]. Subsequently, aging processing was performed on the samples at 150°C for 0 hours and 500 hours, and their tensile strength was measured. TABLE 2
    TABLE 3

    [0061] Table 3 is a table showing the measurement results of samples i to x. "A" of Table 3 is a result of measuring the tensile strength after aging for 0 hours, and "C" of Table 3 is a result of measuring the tensile strength after aging for 500 hours, and the rate The resistibility change is a result obtained by measuring a change in tensile strength after aging for 500 hours while considering "A" (0 hours) as 100%. Additionally, Figure 2 is a graph summarizing the results of measuring the tensile strength of samples i to x.
    [0062] With respect to the aging processing time of 0 hours and 500 hours, it can be understood that Samples ii to x where Bi is added have greater tensile strength than that of Sample i where Bi is not added.
    [0063] Additionally, in the case of aging processing for 500 hours, Samples ii to x in which an additional amount of Bi is 0.1% by mass or more show greater tensile strength than Sample i in which Bi is not added. In addition, samples iv to vii where an additional amount of Bi is 1.0% by mass to 3.0% by mass show the rate of change of resistibility of 98% or greater. It is understood that the rate of change of tensile strength after aging for 500 hours is significantly low and, particularly, that the tensile strength after aging for 500 hours of samples va vii is more improved than in the case where the processing of aging is not performed.
    [0064] However, Sample x where an additional amount of Bi is 6% by mass shows the rate of change in tensile strength of 71.8% which is less than 85.2% of Sample i where Bi does not is added, so it can be said that 6% by mass is not a preferred mixing amount.
    [0065] Additionally, regarding a case of adding Ge to the basic composition of Sn-Cu-Ni-Bi, a change in tensile strength that results from a change in an additional amount of Bi will be described in detail. More specifically, a change in the tensile strength of samples where Bi is added to such a composition in an amount of 0 to 6% by mass was measured.
    [0066] Table 4 is a composition table that shows the compositions of the samples used in measuring tensile strength. As illustrated in Figure 3, Bi is not included in Sample 1 "SAC305" and Sample 2 "SN1." And in Sample 3 "+0.1Bi", Sample 4 "+0.5Bi", Sample 5 "+1.0Bi", Sample 6 "+1.5Bi", Sample 7 "+2.0Bi", Sample 8 " +3.0Bi", Sample 9 "+4.0Bi", Sample 10 "+5.0Bi", and Sample 11 "+6.0Bi", Bi is included in an amount of 0.1% by mass, 0, 5% by mass, 1% by mass, 1.5% by mass, 2% by mass, 3% by mass, 4% by mass, 5% by mass, and 6% by mass, respectively.
    [0067] Additionally, in all samples except for Sample 1 "SAC305", 0.7 mass% Cu, 0.05% mass Ni, and 0.006% mass Ge are included, and the rest is No. Furthermore, in Sample 1 "SAC305", 3% by mass of Ag and 0.5% by mass of Cu are included, and the rest is Sn.
    [0068] Hereinafter, for convenience of explanation, Sample 1 "SAC305", Sample 2 "SN1", Sample 3 "+10.1Bi", Sample 4 "+0.5Bi", Sample 5 "+1.0Bi", Sample 6 "+1.5Bi", Sample 7 "+2.0Bi", Sample 8 "+3.0Bi", Sample 9 "+4.0Bi", Sample 10 "+5.0Bi", and Sample 11 "+6 ,0Bi" will be referred to as "Sample 1", "Sample 2", "Sample 3", "Sample 4", "Sample 5", "Sample 6", "Sample 7", "Sample 8", "Sample 9" , "Sample 10", and "Sample 11", respectively. TABLE 4

    [0069] Samples 1 to 11 having compositions as shown in Table 4 were prepared by the method described above. The aging processing was carried out on samples prepared 1 to 11 for 0 hours and 500 hours at 150°C, and the tensile strength was measured by the method described above. TABLE 5

    [0070] Table 5 is a table showing the measurement results of samples 1 to 11. "A" of Table 5 is a measurement result of tensile strength after aging for 0 hours, and "C" of Table 5 is a result of measuring the tensile strength after aging for 500 hours, and the rate of change of resistibility is a result that shows a change in tensile strength after aging for 500 hours in percentage (%). Additionally, Figure 3 is a graph summarizing the tensile strength measurement results of samples 1 to 11.
    [0071] Regarding the aging processing time of 0 hours and 500 hours, it can be observed that Samples 3 to 11 where Bi is added have greater tensile strength than that of Sample 2 where Bi is not added.
    [0072] Additionally, in the case of aging processing for 500 hours, Samples 4 to 11 in which an additional amount of Bi is 0.5% by mass or more show greater tensile strength than that of Sample 1 where Bi is not added and Ag is added. Furthermore, it can be seen that samples 5 to 8 in which an additional amount of Bi is 1.0% by mass to 3.0% by mass show the rate of change of resistibility of 98% or greater, which is a rate of significantly low tensile strength change after aging for 500 hours.
    [0073] Consequently, in the case of Samples 4 to 11, since Ag is not used, it is possible to achieve a cost reduction while having the effect of improving the tensile strength.
    [0074] Additionally, it can be observed that in the case of Samples 3 to 9, that is, as an additional amount of Bi is increased from 0.1% by mass to 4% by mass, the tensile strength was increased. Furthermore, in such a range of the additional amount of Bi, there is no great difference between the tensile strength of the case where the aging processing has not been carried out and the tensile strength of the case where the input processing. aging was carried out for 500 hours.
    [0075] However, in the case of Samples 10 and 11 where an additional amount of Bi is 5% by mass or more, as the additional amount of Bi increased, the tensile strength of the case where the aging processing did not was performed is increased, however, the rate of change of resistibility tended to be decreased, in particular, in the case of 6% by mass, the rate of change of the tensile strength is 71.8% which is less than 85.2 % of the case where Bi is not added (Sample 2) and therefore it can be said that 6% by mass is not a preferred mixing amount.
    [0076] As can be seen from the above measurement results, when the lead-free solder alloy consisting of Sn, Cu, Ni, Bi, and Ge is exposed to an astringent use environment, i.e., high temperature at 150°C for a long time, it is preferred that an additional amount of Bi is from 0.5 to 4.0% by mass and more preferably from 1.0 to 3.0% by mass. In such a range of the additional amount of Bi as described above, even when aging processing is carried out for 500 hours, high tensile strength can be obtained. Additionally, there is no big difference between the tensile strength of the case where aging processing is not carried out and the tensile strength of the case where aging processing is carried out for 500 hours, that is, a stable tensile strength can be obtained.
    [0077] Furthermore, in the case of Sample 10 where an additional amount of Bi is 5% by mass, the tensile strength after the aging processing was less than the tensile strength of the case where the aging processing was not performed as described above. However, since the tensile strength of Samples 1 and 2 where Bi is not added is less than that of Sample 10 after the aging process has been carried out, the additional amount of Bi can be from 0.1 to 5.0 % in large scale.
    [0078] Additionally, hereinafter, in relation to a case of adding Ge to the basic composition of Sn-Cu-Ni-Bi, a change in tensile strength that results from a change in an additional amount of Cu will be described in detail.
    [0079] In this case, Ni, Bi, and Ge are included in an amount of 0.05% by mass, 1.5% by mass, and 0.006% by mass, respectively. Additionally, Cu is added in an amount of 0.05 to 2.2% by mass, and the rest is Sn. Hereinafter, for convenience of explanation, a sample in which 0.05% by mass of Cu is added, a sample in which 0.1% by mass of Cu is added, a sample in which 0.7% by mass of Cu is added, a sample where 2% by mass Cu is added, and a sample where 2.2% by mass Cu is added will be referred to as "0.05Cu", "0.1Cu", "0.7Cu" , "2Cu", and "2.2Cu", respectively.
    [0080] The samples were prepared by the method described above and the aging processing was performed on the samples prepared at 150°C for 0 hours and 500 hours, and their tensile strength was measured by the method described above. TABLE 6

    [0081] Table 6 is a table showing the results of measuring the tensile strength of samples having different additional amounts of Cu as described above. "A" of Table 6 is a result of measuring the tensile strength after aging for 0 hours, and "C" of Table 4 is a result of measuring the tensile strength after aging for 500 hours. Additionally, Figure 4 is a graph summarizing the tensile strength measurement results of samples having different additional amounts of Cu.
    [0082] All of "0.05Cu" to "2.2Cu" have a desirable resistibility change rate greater than 90% before and after aging. However, since problems such as an increase in so-called Cu leaching can occur, it is not preferable that an additional amount of Cu be 0.05% by mass. However, since problems such as an increase in liquid phase temperature, an occurrence of cavity shrinkage, or the like may occur, it is not preferable that an additional amount of Cu be 2.2% by mass.
    [0083] From the above description, when Ge is added to the basic composition of Sn-Cu-Ni-Bi, in the composition described above, it is preferred that an additional amount of Cu is from 0.1 to 2.0% by mass .
    [0084] Additionally, hereinafter, in relation to the case where Ge is added to the basic composition of Sn-Cu-Ni-Bi, a change in tensile strength that results from a change in an additional amount of Ni will be described in detail.
    [0085] In this case, Cu, Bi, and Ge are included in an amount of 0.7% by mass, 1.5% by mass, and 0.006% by mass, respectively, additionally Ni is added in a amount from 0.005 to 0.55% by mass, and the rest is Sn. Hereinafter, for convenience of explanation, a sample in which 0.005% by mass of Ni is added, a sample in which 0.01% by mass of Ni is added, a sample in which 0.05% by mass of Ni is added, a sample in which 0.5% by mass of Ni is added, and a sample in which 0.55% by mass of Ni is added will be referred to as "0.005Ni", "0.01Ni", "0.05Ni", "0.5Ni", and "0.55Ni", respectively.
    [0086] The samples were prepared by the method described above and the aging processing was performed on the samples prepared at 150°C for 0 hours and 500 hours, and their tensile strength was measured by the method described above. TABLE 7

    [0087] Table 7 is a table showing the results of measuring the tensile strength of samples having different additional amounts of Ni as described above. "A" of Table 7 is a result of measuring the tensile strength after aging for 0 hours, and "C" of Table 7 is a result of measuring the tensile strength after aging for 500 hours. Additionally, Figure 5 is a graph summarizing the tensile strength measurement results of samples having different additional amounts of Ni.
    [0088] All from "0.005Ni" to "0.55Ni" have a desirable resistivity change rate greater than 90% before and after aging. However, it is not preferable that the additional amount of Ni be small as an effect of suppressing granulation of an intermetallic compound at an alloy layer interface may be lost in order to cause fractures. However, it is not preferred that an additional amount of Ni exceed 0.5% by mass as the liquid phase temperature may rise to cause cavity shrinkage to occur.
    [0089] From the above description, when Ge is added to the basic composition of Sn-Cu-Ni-Bi, in the composition described above, it is preferred that an additional amount of Ni is from 0.01 to 0.5% by mass. .
    [0090] Additionally, hereinafter, in relation to the case where Ge is added to the basic composition of Sn-Cu-Ni-Bi, a change in tensile strength that results from a change in an additional amount of Ge will be described in detail.
    [0091] In this case, Cu, Ni, and Bi are included in an amount of 0.7% by mass, 0.05% by mass, and 1.5% by mass, respectively. Additionally, Ge is added in an amount of 0.0001 to 1% by mass, and the rest is Sn. Hereinafter, for convenience of explanation, a sample in which 0.0001% by mass of Ge is added, a sample in which 0.001% by mass of Ge is added, a sample in which 0.006% by mass of Ge is added, a sample where 0.1% by mass of Ge is added, and a sample where 1% by mass of Ge is added will be referred to as "0.0001Ge", "0.001Ge", "0.006Ge", "0.1Ge" , and "1Ge", respectively.
    [0092] The samples were prepared by the method described above and the aging processing was performed on the samples prepared at 150°C for 0 hours and 500 hours, and their tensile strength was measured by the method described above. TABLE 8

    [0093] Table 8 is a table showing the results of measuring the tensile strength of samples that have different additional amounts of Ge as described above. "A" of Table 8 is a result of measuring the tensile strength after aging for 0 hours, and "C" of Table 8 is a result of measuring the tensile strength after aging for 500 hours. Additionally, Figure 6 is a graph summarizing the tensile strength measurement results of samples having different additional amounts of Ge.
    [0094] All of "0.0001Ge" to "0.1Ge" have a desirable resistibility change rate greater than 90% before and after aging. However, it is not preferred that an additional amount of Ge be 0.0001% by mass, as an oxidation-preventing effect can be suppressed. However, when an additional amount of Ge is 1% by mass, the rate of change in resistibility before and after aging is much less than 90%.
    [0095] From the above description, when Ge is added to the basic composition of Sn-Cu-Ni-Bi, in the composition described above, it is preferred that an additional amount of Ge is from 0.001 to 0.1% by mass.
    [0096] However, since the effect of preventing oxidation is expected to improve as the additional amount of Ge is increased, an additional amount of Ge can also be from 0.001 to 1.0% by mass.
    [0097] Additionally, hereinafter, in relation to the case where In is added to the basic composition of Sn-Cu-Ni-Bi, a change in tensile strength that results from a change in an additional amount of In will be described in detail.
    [0098] In this case, Cu, Ni, Bi and Ge are included in an amount of 0.7% by mass, 0.05% by mass, 1.5% by mass, and 0.006% by mass, respectively. Additionally, In is added in an amount of 0 to 10% by mass, and the rest is Sn. Hereinafter, for convenience of explanation, a sample to which 0% by mass of In is added, a sample to which 0.1% by mass of In is added, a sample to which 3% by mass of In is added, a sample where 4% by mass of In is added, a sample where 5% by mass of In is added, a sample where 6% by mass of In is added, a sample where 7% by mass of In is added, and a sample where 10% by mass of In is added will be referred to as "0In", "0.1In", "3In", "4In", "5In", "6In", "7In" and "10In", respectively.
    [0099] The samples were prepared by the method described above and the aging processing was performed on the samples prepared at 150°C for 0 hours and 500 hours, and their tensile strength was measured by the method described above. TABLE 9

    [00100] Table 9 is a table showing the results of measuring the tensile strength of samples having different additional amounts of In (hereinafter, simply referred to as modified In sample) as described above. "A" of Table 9 is a result of measuring the tensile strength after aging for 0 hours, and "C" of Table 9 is a result of measuring the tensile strength after aging for 500 hours. Additionally, Figure 7 is a graph summarizing the tensile strength measurement results of samples having different additional amounts of In.
    [00101] All modified In samples except for "10In" have a desirable resistibility change rate greater than 90% before and after aging. Consequently, it can also be considered that it is effective for the additional amount of In to be from 0.1 to 7% by mass.
    [00102] However, Table 10 is a table showing the elongation rate measurement results of the modified In samples. "A" of Table 10 is a result of measuring the elongation rate after aging for 0 hours, and "C" of Table 10 is a result of measuring the elongation rate after aging for 500 hours, and the rate of change elongation is a result that shows a change in the elongation rate after aging for 500 hours, as a percentage (%). Additionally, Figure 8 is a graph summarizing the results of measuring the elongation rate of the modified In samples described above. TABLE

    [00103] In this document, the elongation rate can be obtained by the following equation. In the equation, "δ" represents the elongation ratio, "Lo" represents a length between gauge points before measuring the tensile strength, "L" is a length between the gauge points after measuring the tensile strength. δ(%) = (L-Lo)/Lo x 100
    [00104] Additionally, the elongation ratio was calculated using the above equation by marking a prescribed length (50 mm, Lo) between the gauge points on a test sample before measuring the tensile strength, and measuring it. if a length (L) between the gauge points at the time of correlated fractured parts of the test specimen after measuring the tensile strength.
    [00105] As can be seen from the Table and Figure 8, in a range where the additional amount of In is 4% by mass (4In) to 6% by mass (6In), all samples have a rate of stable elongation change greater than 100%. That is, in such a range, the elongation rate is improved after aging.
    [00106] In other words, in such a range, transformation can occur more easily after aging than before aging. When an impact is applied from the outside, the impact must be absorbed through the transformation and the resistibility increases, to some extent, overall. Therefore, such improvement in the elongation rate can contribute to the improvement of resistibility.
    [00107] However, when the additional amount of In is excessively large, the temperature at which the transformation starts can be decreased.
    [00108] From the above description, when In is added to the basic composition of Sn-Cu-Ni-Bi, in the composition described above, it is preferred that an additional amount of In is from 0.1 to 6% by mass.
    [00109] However, since it is expected that as the additional amount of In is increased, the liquid phase temperature is decreased and the resistibility is increased and therefore the additional amount of In can also be 0.1 to 10% in large scale.
    [00110] Henceforth, the resistibility change of the sample "SAC305" which includes only Ag, Cu, and Sn without Ni, Ge, and Bi that is added thereto, and samples with the basic composition of Sn-Cu-Ni-Bi where Ge, Sb, In, Ga, P, Co, Al, Ti, or Ag (hereinafter, referred to as an additional element) is added, will be described below. TABLE 11

    [00111] Table 11 is a table showing the results of measuring the tensile strength of samples in which the additional element is added. "A" of Table 11 is a result of measuring the tensile strength after aging for 0 hours, and "C" of Table 11 is a result of measuring the tensile strength after aging for 500 hours. Additionally, Figure 9 is a graph summarizing the tensile strength measurement results of the samples in which the additional element is added.
    [00112] Additionally, a composition of the samples in which the additional element is added is shown in Table 12. Here, since "SAC305" has the same composition as that of "SAC305" (produced by Nihon Superior Co., Ltd.) in Table 4 above, and the composition of "+1.5Bi" (I) was previously shown in Table 2, the compositions thereof will not be represented in detail. TABLE 12
    UNIT: % BY MASS
    [00113] In all samples II to XIV shown in Tables 11 and 12, Cu, Ni and Bi are included in an amount of 0.7% by mass, 0.05% by mass, and 1.5% by mass, respectively. Hereinafter, for convenience of explanation, the content of Cu, Ni, and Bi as described above will be referred to as a basic composition.
    [00114] Furthermore, in samples II and III, Ge is additionally included in an amount of 0.001% by mass or 0.1% by mass, respectively, in addition to the basic composition described above, and the rest is Sn. In addition, samples IV to XIV contain 0.006% by mass of Ge along with the basic composition described above and additionally contain the additional elements.
    [00115] As can be seen from Figure 9 and Table 11, only "SAC305" and "10In" (VII) have a resistance change rate of less than 90% before and after aging. That is, it is determined that, except for Sample vii, the additional element and the corresponding additional amount for each sample maintain the effects of the present invention, which is the effect of improving reliability after aging (improving tensile strength), while bringing unique effects due to the additional elements.
    [00116] For example, Ge and P have a unique effect of preventing the oxidation of Sn and solder ingredients due to oxide films. Ti and Ga have unique auto-oxidation effects and increased bulk resistibility. In has the unique effects of decreasing liquid phase temperature and increasing resistibility, and Ag has the unique effect of increasing resistibility before aging by strengthening dispersion and precipitation. Co has a unique effect of thinning a layer of intermetallic compound, and Al has unique effects of refining the intermetallic compound, which suppresses a decrease in resistibility after aging, and auto-oxidation.
    [00117] Table 13 is a table showing comparisons between the tensile strength of "SAC305" and the tensile strength of Samples I to XIV before and after aging. More specifically, Table 13 shows tensile strength ratios of Samples I to XIV to the tensile strength of "SAC305", and tensile strength ratios of "SAC305" and Samples II to XIV to the tensile strength of Sample I , in percentage (%). In other words, Table 13 shows the relative tensile strength in relation to "SAC305" and Sample I before and after aging. TABLE 13

    [00118] As can be seen from Table 13, all samples II to XIV have a relative tensile strength of 93% or more both before and after aging, in particular, samples V and IX have a tensile strength that exceeds 120% both before and after aging. From the results as described above, it is also determined that in the case of adding the additional elements described above, the effects of the present invention can be maintained, and the unique effects of the additional elements can also be obtained, as described above.
    [00119] If within the range in which the effects of the present invention are obtained, a shape or use of a lead-free solder alloy of the present invention that has Sn-Cu-Ni-Bi as the basic composition is not limited , and the lead-free soldering alloy can be used for flux soldering or reflow soldering. The lead-free solder alloy can have a shape such as a solder paste kind, a resin flux core solder kind, a powder kind, a preform kind, and a sphere kind accordingly. with its use, as well as a type of flux welding rod.
    [00120] Additionally, the present invention is also directed to a soldered joint that is soldered with the lead-free solder alloy of the present invention that is processed to have various shapes. INDUSTRIAL APPLICABILITY
    [00121] The present invention is a lead-free solder alloy that has versatility so as not to be limited by one form of a soldering product and, since the decrease in the resistance of the solder joint joint is little even in a state where it is exposed to high temperature for a long time, the excellent long-term reliability of the weld joint is maintained. Consequently, the present invention can be widely applied to apparatus and devices having soldered joints in which high current flows, apparatus and devices exposed to a state of elevated temperature, or the like, as well as to soldering of electronic devices.
    权利要求:
    Claims (2)
    [0001]
    1. Lead-free and silver-free solder alloy, characterized by the fact that it comprises: 0.1 to 2.0 by mass of Cu; 0.01 to 0.5% by mass of Ni; above 1 and up to 3% by mass of Bi; 0.0001 to 0.1% by mass of Ge; unavoidable impurities; and 76.0 to 99.5% by mass of Sn, which is the balance of the solder alloy.
    [0002]
    2. Welded joint, characterized in that it uses lead-free and silver-free solder alloy as defined in claim 1.
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    同族专利:
    公开号 | 公开日
    PH12016502152A1|2017-01-16|
    RU2016146520A|2018-05-30|
    JP2016129908A|2016-07-21|
    US10286497B2|2019-05-14|
    CA2946994A1|2015-11-05|
    RU2018118008A|2018-11-02|
    HK1259425A1|2019-11-29|
    RU2016146520A3|2018-05-30|
    US20160368102A1|2016-12-22|
    AU2015254179B2|2017-07-20|
    RU2018118008A3|2019-01-25|
    JP5872114B1|2016-03-01|
    CN105339131A|2016-02-17|
    BR112016024855A2|2017-08-15|
    PH12016502152B1|2017-01-16|
    MX2016014012A|2017-01-11|
    KR20160147996A|2016-12-23|
    CA2946994C|2020-04-14|
    AU2015254179A1|2016-11-17|
    RU2662176C2|2018-07-24|
    CN114161023A|2022-03-11|
    SG11201608933SA|2016-12-29|
    EP3138658A1|2017-03-08|
    WO2015166945A1|2015-11-05|
    JP6339993B2|2018-06-06|
    JP2016129907A|2016-07-21|
    JPWO2015166945A1|2017-04-20|
    CN108515289A|2018-09-11|
    EP3708292A1|2020-09-16|
    EP3138658A4|2018-04-11|
    RU2018118007A|2018-11-02|
    RU2018118007A3|2019-02-01|
    EP3138658B1|2020-11-04|
    RU2695791C2|2019-07-26|
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    法律状态:
    2019-08-20| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|
    2020-12-08| B06A| Patent application procedure suspended [chapter 6.1 patent gazette]|
    2021-03-09| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|
    2021-05-04| B16A| Patent or certificate of addition of invention granted [chapter 16.1 patent gazette]|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 28/04/2015, OBSERVADAS AS CONDICOES LEGAIS. |
    优先权:
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    JP2014-094277|2014-04-30|
    JP2014094277|2014-04-30|
    JP2015004403|2015-01-13|
    JP2015-004403|2015-01-13|
    PCT/JP2015/062818|WO2015166945A1|2014-04-30|2015-04-28|Lead-free solder alloy|
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