WO2020044650A1 - Soldering alloy - Google Patents

Soldering alloy Download PDF

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Publication number
WO2020044650A1
WO2020044650A1 PCT/JP2019/016718 JP2019016718W WO2020044650A1 WO 2020044650 A1 WO2020044650 A1 WO 2020044650A1 JP 2019016718 W JP2019016718 W JP 2019016718W WO 2020044650 A1 WO2020044650 A1 WO 2020044650A1
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mass
content
solder alloy
solder
alloy according
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PCT/JP2019/016718
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French (fr)
Japanese (ja)
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英治 日野
広信 澤渡
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Ｊｘ金属株式会社
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Priority to JP2019543866A priority Critical patent/JPWO2020044650A1/en
Priority to CN201980001971.9A priority patent/CN111132794B/en
Publication of WO2020044650A1 publication Critical patent/WO2020044650A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
    • B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
    • B23K35/24—Selection of soldering or welding materials proper
    • B23K35/26—Selection of soldering or welding materials proper with the principal constituent melting at less than 400 degrees C
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C12/00—Alloys based on antimony or bismuth
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
    • H05K3/32—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
    • H05K3/34—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by soldering

Definitions

  • the present invention relates to a solder alloy.
  • solder alloys are soldered from environmental considerations.
  • the temperature range suitable for use as a solder varies depending on the composition of the solder alloy.
  • Power devices are used in a wide range of fields, such as hybrid vehicles and power transmission and transformation, as power conversion elements.
  • SiC devices could be used, but SiC, GaN, etc., which have a larger bandgap than Si, have attracted attention in recent years in fields requiring high breakdown voltage, large current applications, and high-speed operation.
  • the operating temperature of conventional power modules was up to about 170 ° C., but the temperature range of next-generation SiC, GaN, etc. is likely to be 200 ° C. or higher. Accordingly, heat resistance and heat dissipation are required for each material used for a module on which these chips are mounted.
  • Sn-3.0Ag-0.5Cu solder is preferable from the viewpoint of Pb-free, but the melting point is around 220 ° C. because the operating temperature of the next-generation module may exceed 200 ° C. More heat resistance is required than Sn-3.0Ag-0.5Cu solder.
  • solder having a melting point of preferably 250 ° C. or more is required from the viewpoint of cooling of the radiator and tolerance of the temperature around the engine.
  • the composition of the solder is expressed in terms of mass% unless otherwise specified. In the case of Sn-3.0Ag-0.5Cu, the composition of Ag: 3.0 mass%, Cu: 0.5 mass%, and the balance of Sn That is.
  • Pb solder Pb-5Sn
  • Au-based solder Au-Ge, Au-Si, Au-Sn
  • Sn-based solders are known as inexpensive solders (Patent Documents 1 and 2).
  • metal powder paste has attracted attention as a bonding material for next-generation modules. Due to the small size of the metal powder, the surface energy is high and sintering begins at a temperature much lower than the melting point of the metal. And, unlike solder, once it is sintered, it does not re-melt unless it is heated to near the melting point of the metal. Taking advantage of such characteristics, development of an Ag fine powder paste is in progress (Patent Document 3).
  • Pb-5Sn solder has a sufficient function as a bonding material for the next-generation power module, but is leaded, and is desirably not used from the viewpoint of future environmental regulations.
  • Au-based solder is desirable as a bonding material in terms of function and environment, but has a problem of material price.
  • the Sn-based solder has a low melting point and may reduce the bonding strength in a high-temperature environment such as 250 ° C. Further, the Ag fine powder paste can provide sufficient bonding strength and heat resistance to the bonding layer depending on conditions, but has a problem of material price.
  • solder paste of Patent Literature 4 a plurality of types of powders having different compositions are blended and are designed to be alloyed after melting. For that purpose, heating exceeding the melting point of each powder is required. For example, if Cu powder is used, complete melting cannot be expected unless the powder is heated to a melting point of 1084.6 ° C. or higher, and there is a concern about non-uniformity depending on a heating operation at the time of soldering.
  • an object of the present invention is to provide a novel solder alloy that can be used in a high temperature range without being added with lead.
  • the present invention includes the following (1).
  • a solder alloy containing Sn, Bi, and Cu The Sn content is 1.9 to 4.3% by mass, the Cu content is 1.9 to 4.5% by mass, the balance is Bi and inevitable impurities, and the Sn content and the Cu content are Solder alloy that satisfies the following formula: Cu content (% by mass) ⁇ 1.50 ⁇ Sn content (% by mass) ⁇ 1.00 Cu content (% by mass) ⁇ 1.45 ⁇ Sn content (% by mass) ⁇ 1.63
  • solder alloy having excellent properties even in a high temperature range required for a bonding material of a next-generation power module, for example, in a temperature range exceeding 250 ° C. without adding lead. Can be.
  • FIG. 1 is an explanatory diagram illustrating a range of an expression satisfied by the embodiment of the present application.
  • solder alloy of the present invention is a solder alloy containing Sn, Bi, and Cu, and has a Sn content of 1.9 to 4.3% by mass and a Cu content of 1.9 to 4.5%. %, The balance being Bi and unavoidable impurities, the Sn content and the Cu content being in the solder alloy satisfying the following formula: Cu content (% by mass) ⁇ 1.50 ⁇ Sn content (% by mass) ⁇ 1.00 Cu content (% by mass) ⁇ 1.45 ⁇ Sn content (% by mass) ⁇ 1.63
  • the solder alloy of the present invention has a high solidus temperature and a liquidus temperature both in a high temperature range, and in order to maintain sufficient bonding strength even after long-time holding at a high temperature, a bonding material for a next-generation power module is used. It has excellent characteristics even in a high temperature range required for, for example, a temperature range exceeding 250 ° C.
  • the solder alloy of the present invention is advantageous from the viewpoint of future environmental regulations because lead is not intentionally added and contained, and the material is used because expensive Ag is not used. It is also advantageous in terms of price.
  • the unavoidable impurities are not the components intentionally added but the components unavoidably mixed from the material or the process.
  • the metal used as the raw material is a 4N product
  • the inevitable impurities contain 0.01% by mass at the maximum.
  • the solder alloy of the present invention is a so-called lead-free solder alloy. It may be contained.
  • [Bi] Bi bismuth is contained as a main constituent element of the solder alloy of the present invention.
  • the content of Bi in the solder alloy is, for example, 91.2 to 96.2% by mass, preferably 91.3 to 95.9% by mass, or 91.3 to 94.0% by mass. can do.
  • the content of Bi with respect to the solder alloy is, for example, 91.2% by mass or more, preferably 91.3% by mass or more, or 96.2% by mass or less, preferably 95.9% by mass or less. , 94.0% by mass or less.
  • the Sn content with respect to the solder alloy can be, for example, 1.9 to 4.3% by mass, preferably 2.1 to 4.2% by mass, or 3.0 to 4.2% by mass.
  • the content of Sn relative to the solder alloy is, for example, 1.9% by mass or more, preferably 2.1% by mass or more, more preferably 3.0% by mass or more, or for example 4.3% by mass. Or less, preferably 4.2 mass% or less.
  • the content of Cu in the solder alloy is, for example, in the range of 1.9 to 4.5% by mass, preferably 2.0 to 4.5% by mass or 3.0 to 4.5% by mass. It can be.
  • the content of Cu with respect to the solder alloy is, for example, 1.9% by mass or more, preferably 2.0% by mass or more, more preferably 3.0 or more, or for example 4.5% by mass or less. can do. Even if the Cu concentration is 1.9% by mass or more, there is no increase in the liquidus temperature, and the shear strength after 250 ° C. for 1000 hours can be easily secured to 40 MPa or more. On the other hand, if the Cu concentration exceeds 4.50 mass%, the adhesion of the solder to the manufacturing equipment cannot be ignored and continuous manufacturing becomes difficult.
  • the Cu and Sn contents satisfy the following formula: Cu content (% by mass) ⁇ 1.50 ⁇ Sn content (% by mass) ⁇ 1.00 Cu content (% by mass) ⁇ 1.45 ⁇ Sn content (% by mass) ⁇ 1.63
  • the Cu and Sn contents satisfy the following formula: Cu content (% by mass) ⁇ 1.50 ⁇ Sn content (% by mass) ⁇ 1.16 Cu content (% by mass) ⁇ 1.45 ⁇ Sn content (% by mass) ⁇ 1.50
  • the Cu and Sn contents satisfy the following formula: Cu content (% by mass) ⁇ 1.50 ⁇ Sn content (% by mass) ⁇ 1.50 Cu content (% by mass) ⁇ 1.45 ⁇ Sn content (% by mass) ⁇ 1.50
  • the solidus temperature can be, for example, 228 ° C. or higher, or 235 ° C. or higher.
  • the shear strength after 1000 hours under a 250 ° C. environment is 40 MPa or more, so that it can be used sufficiently in a high temperature range.
  • the liquidus temperature can be, for example, 272 ° C or lower, 270 ° C or lower, or 268 ° C or lower.
  • [Liquid temperature and solidus temperature] In a preferred embodiment, the value of the following equation: [liquidus temperature]-[solidus temperature] (solidus liquidus temperature difference: PR) is, for example, 33 ° C or less, or 24 ° C or less. Can be.
  • the composition of the solder alloy can be, for example, as follows.
  • Sn: Bi: Cu 2.1 to 4.2% by mass: 91.3 to 95.9% by mass: 2.0 to 4.5% by mass, which satisfies the following formula: Cu content (% by mass) ⁇ 1.50 ⁇ Sn content (% by mass) ⁇ 1.16 Cu content (% by mass) ⁇ 1.45 ⁇ Sn content (% by mass) ⁇ 1.50
  • Sn: Bi: Cu 3.0 to 4.2% by mass: 91.3 to 94.0% by mass: 3.0 to 4.5% by mass, which satisfies the following formula: Cu content (% by mass) ⁇ 1.50 ⁇ Sn content (% by mass) ⁇ 1.50 Cu content (% by mass) ⁇ 1.45 ⁇ Sn content (% by mass) ⁇ 1.50
  • the bonding strength of the solder alloy can be measured by the means described in the examples.
  • the bonding strength can be set as the shear strength after one or three reflow treatments, for example, 39 MPa or more, 43 MPa or more, or 47 MPa or more as the shear strength after one reflow treatment.
  • the shear strength after three reflow treatments can be, for example, 39 MPa or more, or 47 MPa or more, preferably 54 MPa or more.
  • the bonding strength can be, for example, 40 MPa or more, or 43 MPa or more, preferably 46 MPa or more, as the shear strength measured after being kept at 250 ° C. for 1000 hours in an air atmosphere.
  • solder alloy shape As the shape of the solder alloy of the present invention, a shape as required for use as a solder can be appropriately adopted. It can be a sheet-shaped member as described in the examples, and further can be a member having a shape such as a wire, a powder, a ball, a plate, and a bar.
  • the shape of the solder alloy is particularly preferably a powder shape, a solder ball shape (ball shape), or a sheet shape.
  • the solder ball is, for example, a ball having a diameter of 50 ⁇ m to 500 ⁇ m.
  • the term “solder powder” may be used to include the powder and the solder balls.
  • the solder powder can be used for a solder paste. In this case, for example, a powder having a particle size of less than 50 ⁇ m can be used.
  • the present invention includes the following (1).
  • a solder alloy containing Sn, Bi, and Cu The Sn content is 1.9 to 4.3% by mass, the Cu content is 1.9 to 4.5% by mass, the balance is Bi and inevitable impurities, and the Sn content and the Cu content are Solder alloy that satisfies the following formula: Cu content (% by mass) ⁇ 1.50 ⁇ Sn content (% by mass) ⁇ 1.00 Cu content (% by mass) ⁇ 1.45 ⁇ Sn content (% by mass) ⁇ 1.63
  • a printed circuit board comprising the solder alloy according to any one of (1) to (8).
  • An electronic component comprising the solder alloy according to any one of (1) to (8).
  • a power transistor comprising the solder alloy according to any one of (1) to (8).
  • An electronic device comprising the solder joint according to (11) or (12), the printed circuit board according to (13), the electronic component according to (14), or the power transistor according to (15).
  • the present invention is a member made of the above-mentioned solder alloy, an internal joint solder joint of an electronic component soldered with the solder alloy, a solder joint of a power transistor soldered with the solder alloy, It includes a printed circuit board having the solder alloy, an electronic component having the solder alloy, and a power transistor having the solder alloy.
  • the present invention includes the above-described solder joint, a printed circuit board, an electronic component, and an electronic device having a power transistor, and includes a power device having the above-described solder joint.
  • Example 1 A predetermined amount of Bi, Cu, and Sn chip raw materials was charged into a graphite crucible, the graphite crucible was set in an atomizing apparatus, an inert gas atmosphere was maintained, and a predetermined time was maintained until the raw materials were uniformly dissolved to obtain a molten metal. Thereafter, the stopper installed at the bottom of the graphite crucible was pulled up, and the molten metal was dropped on the lower part. At that time, an inert gas was sprayed on the molten metal to produce a solder powder. 0.5 g of the solder powder was accurately weighed and dissolved in an acid, and then the concentration was measured with an ICP emission spectrometer. The result is shown in Table 1.
  • Example 2 In the same procedure as in Example 1, a solder powder was prepared, the concentration was measured with an ICP emission spectrometer, and the solidus temperature, liquidus temperature, and melting point were measured by differential scanning calorimetry. After the treatment, the shear strength after three reflow treatments and after the high temperature test were measured. The results are summarized in Table 1.
  • solder alloys of Examples 1 to 6 maintained a sufficient shear strength even after the high temperature test (after a lapse of 1000 hours at 250 ° C.).
  • Example 1 had substantially the same Cu content as Comparative Example 4, but had a significantly improved shear strength after a high-temperature test due to a different Sn content.
  • Example 3 as compared with Comparative Example 7, the Cu content was almost the same, but the Sn content was different, so that the shear strength after the high-temperature test was greatly improved.
  • Example 5 as compared with Comparative Example 10, the Cu content was almost the same, but the Sn content was different, so that the shear strength after the high-temperature test was greatly improved.
  • compositions of the solder alloys of Examples 1 to 6 satisfied the following ranges: 1.9 ⁇ Sn content (% by mass) ⁇ 4.3 1.9 ⁇ Cu content (% by mass) ⁇ 4.5 Cu content (% by mass) ⁇ 1.50 ⁇ Sn content (% by mass) ⁇ 1.00 Cu content (% by mass) ⁇ 1.45 ⁇ Sn content (% by mass) ⁇ 1.63
  • the present invention provides a solder alloy having excellent properties in a high temperature range.
  • the present invention is an industrially useful invention.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
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  • Microelectronics & Electronic Packaging (AREA)
  • Electric Connection Of Electric Components To Printed Circuits (AREA)

Abstract

Provided is a novel lead-free soldering alloy that can be used in a high temperature range. This soldering alloy contains Sn, Bi, and Cu, wherein the Sn content is 1.9 to 4.3% by mass, the Cu content is 1.9 to 4.5% by mass, the remainder is Bi and unavoidable impurities, and the Sn content and the Cu content satisfy the formula: Cu content (% by mass) ≤ 1.50 × Sn content (% by mass) - 1.00 Cu content (% by mass) ≥ 1.45 × Sn content (% by mass) - 1.63.

Description

はんだ合金Solder alloy
　本発明は、はんだ合金に関する。 The present invention relates to a solder alloy.
　環境面の配慮から、鉛を含有しないはんだ合金の使用が推奨されている。はんだ合金は、その組成に応じてはんだとしての使用に適した温度域が変わってくる。 か ら Use of lead-free solder alloys is recommended from environmental considerations. The temperature range suitable for use as a solder varies depending on the composition of the solder alloy.
　パワーデバイスは、電力変換用の素子として、ハイブリッド自動車、送変電など幅広い分野で使用されている。従来はＳｉチップのデバイスで対応できたが、高耐圧、大電流用途、高速動作が求められる分野では、Ｓｉよりもバンドギャップが大きいＳｉＣ、ＧａＮ等が近年注目を浴びている。 Power devices are used in a wide range of fields, such as hybrid vehicles and power transmission and transformation, as power conversion elements. In the past, SiC devices could be used, but SiC, GaN, etc., which have a larger bandgap than Si, have attracted attention in recent years in fields requiring high breakdown voltage, large current applications, and high-speed operation.
　従来のパワーモジュールでは動作温度が１７０℃程度までであったのが、次世代型のＳｉＣ、ＧａＮ等では２００℃あるいはそれ以上の温度域となる可能性があるとされる。これに伴い、これらチップを搭載したモジュールに使用される各材料には耐熱性、放熱性が求められている。 動作 The operating temperature of conventional power modules was up to about 170 ° C., but the temperature range of next-generation SiC, GaN, etc. is likely to be 200 ° C. or higher. Accordingly, heat resistance and heat dissipation are required for each material used for a module on which these chips are mounted.
　接合材料に関して言えば、Ｐｂフリーの観点からＳｎ－３．０Ａｇ－０．５Ｃｕはんだが好ましいが、次世代型モジュールでは動作温度が２００℃を超える可能性があるので、融点が２２０℃付近であるＳｎ－３．０Ａｇ－０．５Ｃｕはんだよりも、さらに耐熱性が求められる。具体的にはラジエターの冷却およびエンジン回りの温度の許容性から、好ましくは２５０℃以上の融点を持つはんだが求められる。なお、はんだの組成は、特に断りがなければ質量％表示であり、上記Ｓｎ－３．０Ａｇ－０．５Ｃｕは、Ａｇ：３．０質量％、Ｃｕ：０．５質量％、残部Ｓｎの組成のことである。ＲｏＨＳの規制対象外ではあるものの、環境規制の観点から好ましくないＰｂはんだ（Ｐｂ－５Ｓｎ）であれば次世代型モジュールの動作温度には対応しうる。Ｐｂはんだと同様に耐熱はんだとしてはＡｕ系はんだ（Ａｕ－Ｇｅ、Ａｕ－Ｓｉ、Ａｕ－Ｓｎ）が使用されている（非特許文献１～３）。廉価なはんだとしてはＳｎベースのはんだが知られている（特許文献１、２）。 Speaking of the bonding material, Sn-3.0Ag-0.5Cu solder is preferable from the viewpoint of Pb-free, but the melting point is around 220 ° C. because the operating temperature of the next-generation module may exceed 200 ° C. More heat resistance is required than Sn-3.0Ag-0.5Cu solder. Specifically, solder having a melting point of preferably 250 ° C. or more is required from the viewpoint of cooling of the radiator and tolerance of the temperature around the engine. The composition of the solder is expressed in terms of mass% unless otherwise specified. In the case of Sn-3.0Ag-0.5Cu, the composition of Ag: 3.0 mass%, Cu: 0.5 mass%, and the balance of Sn That is. Pb solder (Pb-5Sn), which is not subject to RoHS regulation but is not desirable from the viewpoint of environmental regulation, can correspond to the operating temperature of the next-generation module. Au-based solder (Au-Ge, Au-Si, Au-Sn) is used as the heat-resistant solder in the same manner as the Pb solder (Non-patent Documents 1 to 3). Sn-based solders are known as inexpensive solders (Patent Documents 1 and 2).
　そこで、近年次世代型モジュールの接合材料として注目されているのが金属微粉ペーストである。金属粉のサイズが小さいので、表面エネルギーが高く、その金属の融点よりもはるかに低い温度で焼結が始まる。そして、はんだとは異なり、いったん焼結すれば、その金属の融点近くまで昇温しないと再溶融しない。このような特性を生かし、Ａｇ微粉ペーストで開発が進んでいる（特許文献３）。 Therefore, in recent years, metal powder paste has attracted attention as a bonding material for next-generation modules. Due to the small size of the metal powder, the surface energy is high and sintering begins at a temperature much lower than the melting point of the metal. And, unlike solder, once it is sintered, it does not re-melt unless it is heated to near the melting point of the metal. Taking advantage of such characteristics, development of an Ag fine powder paste is in progress (Patent Document 3).
　Ｐｂ－５Ｓｎはんだは次世代型パワーモジュールの接合材料としての機能は十分であるが、有鉛であり、将来的な環境規制の観点からも使用しないことが望ましい。また、Ａｕ系はんだは機能、環境面からは接合材料としては望ましいが、材料価格の問題点を抱える。Ｓｎベースはんだは融点が低く例えば２５０℃のような高温環境下において、接合強度を低下させる恐れがある。また、Ａｇ微粉ペーストは条件によっては十分な接合強度、耐熱性を接合層に付与することが可能であるが、材料価格の問題点を抱える。 Pb-5Sn solder has a sufficient function as a bonding material for the next-generation power module, but is leaded, and is desirably not used from the viewpoint of future environmental regulations. Au-based solder is desirable as a bonding material in terms of function and environment, but has a problem of material price. The Sn-based solder has a low melting point and may reduce the bonding strength in a high-temperature environment such as 250 ° C. Further, the Ag fine powder paste can provide sufficient bonding strength and heat resistance to the bonding layer depending on conditions, but has a problem of material price.
　特許文献４のソルダペーストでは、組成の異なる複数種の粉末がブレンドされていて、それが溶融後に合金となる設計となっているが、そのためにはそれぞれの粉末の融点を超える加熱が必要であり、例えばＣｕ粉を用いるならばＣｕの融点１０８４．６℃以上に加熱しないと完全な溶融は期待できず、はんだ付け時の加熱操作に依存した不均一性の懸念がある。 In the solder paste of Patent Literature 4, a plurality of types of powders having different compositions are blended and are designed to be alloyed after melting. For that purpose, heating exceeding the melting point of each powder is required. For example, if Cu powder is used, complete melting cannot be expected unless the powder is heated to a melting point of 1084.6 ° C. or higher, and there is a concern about non-uniformity depending on a heating operation at the time of soldering.
特開平９－２７１９８１号公報JP-A-9-271981 特開２０００－１４１０７９号公報JP 2000-141079 A 国際公開ＷＯ２０１１／１５５０５５号International Publication WO2011 / 155055 国際公開ＷＯ２００７／０５５３０８号International Publication WO2007 / 055308
　このように、次世代型パワーモジュールの接合材料に求められる高温域、例えば２５０℃を超える温度域においても、優れた特性を有するはんだ合金が、求められていた。 As described above, there has been a demand for a solder alloy having excellent characteristics even in a high temperature range required for a bonding material of a next-generation power module, for example, a temperature range exceeding 250 ° C.
　したがって、本発明の目的は、鉛が添加されて含まれることなく、高温域において使用可能な、新規のはんだ合金を提供することにある。 Accordingly, an object of the present invention is to provide a novel solder alloy that can be used in a high temperature range without being added with lead.
　本発明者は、鋭意研究の結果、後述するＢｉベースのはんだ合金によって、上記目的を達成できることを見いだして、本発明に到達した。 As a result of diligent research, the present inventor has found that the above object can be achieved by a Bi-based solder alloy described later, and has reached the present invention.
　したがって、本発明は以下の（１）を含む。
（１）
　Ｓｎ、Ｂｉ、及びＣｕを含有するはんだ合金であって、
　Ｓｎ含有量が１．９～４．３質量％であり、Ｃｕ含有量が１．９～４．５質量％であり、残部がＢｉ及び不可避不純物であり、Ｓｎ含有量とＣｕ含有量が、以下の式を満たす、はんだ合金：
　Ｃｕ含有量（質量％）≦１．５０×Ｓｎ含有量（質量％）－１．００
　Ｃｕ含有量（質量％）≧１．４５×Ｓｎ含有量（質量％）－１．６３ Therefore, the present invention includes the following (1).
(1)
A solder alloy containing Sn, Bi, and Cu,
The Sn content is 1.9 to 4.3% by mass, the Cu content is 1.9 to 4.5% by mass, the balance is Bi and inevitable impurities, and the Sn content and the Cu content are Solder alloy that satisfies the following formula:
Cu content (% by mass) ≦ 1.50 × Sn content (% by mass) −1.00
Cu content (% by mass) ≧ 1.45 × Sn content (% by mass) −1.63
　本発明によれば、鉛が添加されて含まれることなく、次世代型パワーモジュールの接合材料に求められる高温域、例えば２５０℃を超える温度域においても、優れた特性を有するはんだ合金を得ることができる。 According to the present invention, it is possible to obtain a solder alloy having excellent properties even in a high temperature range required for a bonding material of a next-generation power module, for example, in a temperature range exceeding 250 ° C. without adding lead. Can be.
図１は、本願の実施例が満たす式の範囲を図示した説明図である。FIG. 1 is an explanatory diagram illustrating a range of an expression satisfied by the embodiment of the present application.
　以下に本発明を実施の態様をあげて詳細に説明する。本発明は以下にあげる具体的な実施の態様に限定されるものではない。 (4) The present invention will be described in detail below with reference to embodiments. The present invention is not limited to the specific embodiments described below.
［はんだ合金］
　本発明のはんだ合金は、Ｓｎ、Ｂｉ、及びＣｕを含有するはんだ合金であって、Ｓｎ含有量が１．９～４．３質量％であり、Ｃｕ含有量が１．９～４．５質量％であり、残部がＢｉ及び不可避不純物であり、Ｓｎ含有量とＣｕ含有量が、以下の式を満たす、はんだ合金にある：
　Ｃｕ含有量（質量％）≦１．５０×Ｓｎ含有量（質量％）－１．００
　Ｃｕ含有量（質量％）≧１．４５×Ｓｎ含有量（質量％）－１．６３ [Solder alloy]
The solder alloy of the present invention is a solder alloy containing Sn, Bi, and Cu, and has a Sn content of 1.9 to 4.3% by mass and a Cu content of 1.9 to 4.5%. %, The balance being Bi and unavoidable impurities, the Sn content and the Cu content being in the solder alloy satisfying the following formula:
Cu content (% by mass) ≦ 1.50 × Sn content (% by mass) −1.00
Cu content (% by mass) ≧ 1.45 × Sn content (% by mass) −1.63
　本発明のはんだ合金は、固相線温度及び液相線温度がともに高い温度帯であり、高温での長時間保持後にも十分な接合強度を維持するために、次世代型パワーモジュールの接合材料に求められる高温域、例えば２５０℃を超える温度域においても、優れた特性を有する。好適な実施の態様において、本発明のはんだ合金は、鉛が意図的添加されて含まれることがないために、将来の環境規制の観点からも有利であり、高価なＡｇを使用しないために材料価格の点からも有利である。 The solder alloy of the present invention has a high solidus temperature and a liquidus temperature both in a high temperature range, and in order to maintain sufficient bonding strength even after long-time holding at a high temperature, a bonding material for a next-generation power module is used. It has excellent characteristics even in a high temperature range required for, for example, a temperature range exceeding 250 ° C. In a preferred embodiment, the solder alloy of the present invention is advantageous from the viewpoint of future environmental regulations because lead is not intentionally added and contained, and the material is used because expensive Ag is not used. It is also advantageous in terms of price.
　不可避不純物とは、意図的に添加した成分ではなく、材料あるいは工程に由来して不可避的に混入した成分をいう。例えば、原料となる金属が４Ｎ品であれば、不可避不純物は最大０．０１質量％含んでいることになる。好適な実施の態様において、本発明のはんだ合金は、いわゆる無鉛はんだ合金であるが、例えばＲｏＨＳ指令によって規定されている鉛含有率１０００ｐｐｍ（０．１質量％）以下の範囲で不可避不純物として鉛を含有していてもよい。 The unavoidable impurities are not the components intentionally added but the components unavoidably mixed from the material or the process. For example, if the metal used as the raw material is a 4N product, the inevitable impurities contain 0.01% by mass at the maximum. In a preferred embodiment, the solder alloy of the present invention is a so-called lead-free solder alloy. It may be contained.
［Ｂｉ］
　Ｂｉ（ビスマス）が、本発明のはんだ合金の主要な構成元素として、含有される。好適な実施の態様において、はんだ合金に対するＢｉの含有量は、例えば９１．２～９６．２質量％、好ましくは９１．３～９５．９質量％、あるいは９１．３～９４．０質量％とすることができる。好適な実施の態様において、はんだ合金に対するＢｉの含有量は、例えば９１．２質量％以上、好ましくは９１．３質量％以上、あるいは例えば９６．２質量％以下、好ましくは９５．９質量％以下、９４．０質量％以下とすることができる。このような範囲とすることによって、２５０℃１０００時間後のシェア強度をさらに高い範囲のものとすることができる。 [Bi]
Bi (bismuth) is contained as a main constituent element of the solder alloy of the present invention. In a preferred embodiment, the content of Bi in the solder alloy is, for example, 91.2 to 96.2% by mass, preferably 91.3 to 95.9% by mass, or 91.3 to 94.0% by mass. can do. In a preferred embodiment, the content of Bi with respect to the solder alloy is, for example, 91.2% by mass or more, preferably 91.3% by mass or more, or 96.2% by mass or less, preferably 95.9% by mass or less. , 94.0% by mass or less. By setting such a range, the shear strength after 250 ° C. for 1000 hours can be further increased.
［Ｓｎ］
　はんだ合金に対するＳｎの含有量は、例えば１．９～４．３質量％、好ましくは２．１～４．２質量％、あるいは３．０～４．２質量％とすることができる。好適な実施の態様において、はんだ合金に対するＳｎの含有量は、例えば１．９質量％以上、好ましくは２．１質量％以上、さらに好ましくは３．０質量％以上、あるいは例えば４．３質量％以下、好ましくは４．２質量％以下とすることができる。 [Sn]
The Sn content with respect to the solder alloy can be, for example, 1.9 to 4.3% by mass, preferably 2.1 to 4.2% by mass, or 3.0 to 4.2% by mass. In a preferred embodiment, the content of Sn relative to the solder alloy is, for example, 1.9% by mass or more, preferably 2.1% by mass or more, more preferably 3.0% by mass or more, or for example 4.3% by mass. Or less, preferably 4.2 mass% or less.
［Ｃｕ］
　好適な実施の態様において、はんだ合金に対するＣｕの含有量は、例えば１．９～４．５質量％、好ましくは２．０～４．５質量％あるいは３．０～４．５質量％の範囲とすることができる。好適な実施の態様において、はんだ合金に対するＣｕの含有量は、例えば１．９質量％以上、好ましくは２．０質量％以上、さらに好ましくは３．０以上、あるいは例えば４．５質量％以下とすることができる。Ｃｕ濃度を１．９質量％以上にしても液相線温度の上昇もなく、かつ２５０℃１０００時間後のシェア強度を４０ＭＰａ以上に確保しやすくなる。またＣｕ濃度を４．５０質量％を超えると、製造装置へのはんだ付着が無視できなくなり、連続製造が困難となる。 [Cu]
In a preferred embodiment, the content of Cu in the solder alloy is, for example, in the range of 1.9 to 4.5% by mass, preferably 2.0 to 4.5% by mass or 3.0 to 4.5% by mass. It can be. In a preferred embodiment, the content of Cu with respect to the solder alloy is, for example, 1.9% by mass or more, preferably 2.0% by mass or more, more preferably 3.0 or more, or for example 4.5% by mass or less. can do. Even if the Cu concentration is 1.9% by mass or more, there is no increase in the liquidus temperature, and the shear strength after 250 ° C. for 1000 hours can be easily secured to 40 MPa or more. On the other hand, if the Cu concentration exceeds 4.50 mass%, the adhesion of the solder to the manufacturing equipment cannot be ignored and continuous manufacturing becomes difficult.
［Ｃｕ含有量とＳｎ含有量の関係］
　好適な実施の態様において、Ｃｕ含有量とＳｎ含有量は次の式を満たす：
　Ｃｕ含有量（質量％）≦１．５０×Ｓｎ含有量（質量％）－１．００
　Ｃｕ含有量（質量％）≧１．４５×Ｓｎ含有量（質量％）－１．６３
　好適な実施の態様において、Ｃｕ含有量とＳｎ含有量は次の式を満たす：
　Ｃｕ含有量（質量％）≦１．５０×Ｓｎ含有量（質量％）－１．１６
　Ｃｕ含有量（質量％）≧１．４５×Ｓｎ含有量（質量％）－１．５０
　さらに好適な実施の態様において、Ｃｕ含有量とＳｎ含有量は次の式を満たす：
　Ｃｕ含有量（質量％）≦１．５０×Ｓｎ含有量（質量％）－１．５０
　Ｃｕ含有量（質量％）≧１．４５×Ｓｎ含有量（質量％）－１．５０ [Relationship between Cu content and Sn content]
In a preferred embodiment, the Cu and Sn contents satisfy the following formula:
Cu content (% by mass) ≦ 1.50 × Sn content (% by mass) −1.00
Cu content (% by mass) ≧ 1.45 × Sn content (% by mass) −1.63
In a preferred embodiment, the Cu and Sn contents satisfy the following formula:
Cu content (% by mass) ≦ 1.50 × Sn content (% by mass) −1.16
Cu content (% by mass) ≧ 1.45 × Sn content (% by mass) −1.50
In a further preferred embodiment, the Cu and Sn contents satisfy the following formula:
Cu content (% by mass) ≦ 1.50 × Sn content (% by mass) −1.50
Cu content (% by mass) ≧ 1.45 × Sn content (% by mass) −1.50
［固相線温度］
　固相線温度は、例えば２２８℃以上、あるいは２３５℃以上とすることができる。固相線温度が高い（例えば２３５℃以上）はんだ合金の場合２５０℃環境下で、１０００時間後のシェア強度が４０ＭＰａ以上あるので、高温域で十分使用できる。 [Solidus temperature]
The solidus temperature can be, for example, 228 ° C. or higher, or 235 ° C. or higher. In the case of a solder alloy having a high solidus temperature (for example, 235 ° C. or more), the shear strength after 1000 hours under a 250 ° C. environment is 40 MPa or more, so that it can be used sufficiently in a high temperature range.
［液相線温度］
　液相線温度は、例えば２７２℃以下、２７０℃以下、あるいは２６８℃以下とすることができる。 [Liquid phase temperature]
The liquidus temperature can be, for example, 272 ° C or lower, 270 ° C or lower, or 268 ° C or lower.
［液相線温度と固相線温度］
　好適な実施の態様において、次の式：　［液相線温度］－［固相線温度］の値（固相液相温度差：ＰＲ）を、例えば３３℃以下、あるいは２４℃以下とすることができる。 [Liquid temperature and solidus temperature]
In a preferred embodiment, the value of the following equation: [liquidus temperature]-[solidus temperature] (solidus liquidus temperature difference: PR) is, for example, 33 ° C or less, or 24 ° C or less. Can be.
［好適な組成］
　好適な実施の態様において、はんだ合金の組成は、例えば以下とすることができる。
　Ｓｎ：Ｂｉ：Ｃｕ＝２．１～４．２質量％：９１．３～９５．９質量％：２．０～４．５質量％であって、次の式を満たす組成：
　Ｃｕ含有量（質量％）≦１．５０×Ｓｎ含有量（質量％）－１．１６
　Ｃｕ含有量（質量％）≧１．４５×Ｓｎ含有量（質量％）－１．５０
　Ｓｎ：Ｂｉ：Ｃｕ＝３．０～４．２質量％：９１．３～９４．０質量％：３．０～４．５質量％であって、次の式を満たす組成：
　Ｃｕ含有量（質量％）≦１．５０×Ｓｎ含有量（質量％）－１．５０
　Ｃｕ含有量（質量％）≧１．４５×Ｓｎ含有量（質量％）－１．５０ [Suitable composition]
In a preferred embodiment, the composition of the solder alloy can be, for example, as follows.
Sn: Bi: Cu = 2.1 to 4.2% by mass: 91.3 to 95.9% by mass: 2.0 to 4.5% by mass, which satisfies the following formula:
Cu content (% by mass) ≦ 1.50 × Sn content (% by mass) −1.16
Cu content (% by mass) ≧ 1.45 × Sn content (% by mass) −1.50
Sn: Bi: Cu = 3.0 to 4.2% by mass: 91.3 to 94.0% by mass: 3.0 to 4.5% by mass, which satisfies the following formula:
Cu content (% by mass) ≦ 1.50 × Sn content (% by mass) −1.50
Cu content (% by mass) ≧ 1.45 × Sn content (% by mass) −1.50
［接合強度］
　はんだ合金の接合強度は、実施例に記載の手段によって、測定することができる。好適な実施の態様において、接合強度は、リフロー１回もしくは３回処理後のシェア強度として、例えばリフロー１回処理後のシェア強度として例えば３９ＭＰａ以上、４３ＭＰａ以上、あるいは４７ＭＰａ以上とすることができる。リフロー３回処理後とは、リフロー処理を３回実施する処理を行ったことをいう。またリフロー３回処理後のシェア強度として、例えば３９ＭＰａ以上、あるいは４７ＭＰａ以上好ましくは５４ＭＰａ以上とすることができる。好適な実施の態様において、接合強度は、空気雰囲気下２５０℃で１０００時間保持した後に測定したシェア強度として、例えば４０ＭＰａ以上、あるいは４３ＭＰａ以上、好ましくは４６ＭＰａ以上とすることができる。 [Joint strength]
The bonding strength of the solder alloy can be measured by the means described in the examples. In a preferred embodiment, the bonding strength can be set as the shear strength after one or three reflow treatments, for example, 39 MPa or more, 43 MPa or more, or 47 MPa or more as the shear strength after one reflow treatment. After the reflow process three times means that the process of performing the reflow process three times has been performed. The shear strength after three reflow treatments can be, for example, 39 MPa or more, or 47 MPa or more, preferably 54 MPa or more. In a preferred embodiment, the bonding strength can be, for example, 40 MPa or more, or 43 MPa or more, preferably 46 MPa or more, as the shear strength measured after being kept at 250 ° C. for 1000 hours in an air atmosphere.
［はんだ合金の形状］
　本発明のはんだ合金の形状は、はんだとして使用するために必要に応じた形状を、適宜採用することができる。実施例に記載のようにシート形状の部材とすることができ、さらに、例えばワイヤー、粉、ボール、板、棒などの形状の部材とすることができる。はんだ合金の形状は、粉体の形状、はんだボールの形状（ボール状）、又はシート状とすることが特に好ましい。はんだボールは、例えば直径５０μｍ～５００μｍのボールをいう。好適な実施の態様において、粉体とはんだボールとを包含して、はんだ粉と称することがある。はんだ粉は、はんだペースト用に使用することができ、この場合は、例えば粒径５０μｍ未満のものを用いることができる。 [Solder alloy shape]
As the shape of the solder alloy of the present invention, a shape as required for use as a solder can be appropriately adopted. It can be a sheet-shaped member as described in the examples, and further can be a member having a shape such as a wire, a powder, a ball, a plate, and a bar. The shape of the solder alloy is particularly preferably a powder shape, a solder ball shape (ball shape), or a sheet shape. The solder ball is, for example, a ball having a diameter of 50 μm to 500 μm. In a preferred embodiment, the term “solder powder” may be used to include the powder and the solder balls. The solder powder can be used for a solder paste. In this case, for example, a powder having a particle size of less than 50 μm can be used.
［好適な実施の態様］
　好適な実施の態様において、本願発明は、次の（１）以下を含む。
（１）
　Ｓｎ、Ｂｉ、及びＣｕを含有するはんだ合金であって、
　Ｓｎ含有量が１．９～４．３質量％であり、Ｃｕ含有量が１．９～４．５質量％であり、残部がＢｉ及び不可避不純物であり、Ｓｎ含有量とＣｕ含有量が、以下の式を満たす、はんだ合金：
　Ｃｕ含有量（質量％）≦１．５０×Ｓｎ含有量（質量％）－１．００
　Ｃｕ含有量（質量％）≧１．４５×Ｓｎ含有量（質量％）－１．６３
（２）
　Ｂｉ含有量が９１．２～９６．２質量％である、（１）に記載のはんだ合金。
（３）
　固相線温度が２３５℃以上である、（１）～（２）のいずれかに記載のはんだ合金。
（４）
　液相線温度が２７２℃以下である、（１）～（３）のいずれかに記載のはんだ合金。
（５）
　次の式：　［液相線温度］－［固相線温度］
の値が、３３℃以下である、（１）～（４）のいずれかに記載のはんだ合金。
（６）
　リフロー１回処理後の接合強度が３９ＭＰａ以上である、（１）～（５）のいずれかに記載のはんだ合金。
（７）
　リフロー３回処理後の接合強度が３９ＭＰａ以上である、（１）～（６）のいずれかに記載のはんだ合金。
（８）
　２５０℃１０００時間の高温保持後の接合強度が４０ＭＰａ以上である、（１）～（７）のいずれかに記載のはんだ合金。
（９）
　はんだ合金の形状が、粉状、ボール状、又はシート状である、（１）～（８）のいずれかに記載のはんだ合金。
（１０）
　（１）～（８）のいずれかに記載のはんだ合金を材料とした部材。
（１１）
　（１）～（８）のいずれかに記載のはんだ合金ではんだ付けされた電子部品の内部接合はんだ継手。
（１２）
（１）～（８）のいずれかに記載のはんだ合金ではんだ付けされたパワートランジスタのはんだ継手。
（１３）
　（１）～（８）のいずれかに記載のはんだ合金を有するプリント回路板。
（１４）
　（１）～（８）のいずれかに記載のはんだ合金を有する電子部品。
（１５）
　（１）～（８）のいずれかに記載のはんだ合金を有するパワートランジスタ。
（１６）
　（１１）または（１２）に記載のはんだ継手又は（１３）に記載のプリント回路板または（１４）に記載の電子部品または（１５）に記載のパワートランジスタを有する電子機器。
（１７）
　（１１）または（１２）に記載のはんだ継手を有するパワーデバイス。 [Preferred Embodiment]
In a preferred embodiment, the present invention includes the following (1).
(1)
A solder alloy containing Sn, Bi, and Cu,
The Sn content is 1.9 to 4.3% by mass, the Cu content is 1.9 to 4.5% by mass, the balance is Bi and inevitable impurities, and the Sn content and the Cu content are Solder alloy that satisfies the following formula:
Cu content (% by mass) ≦ 1.50 × Sn content (% by mass) −1.00
Cu content (% by mass) ≧ 1.45 × Sn content (% by mass) −1.63
(2)
The solder alloy according to (1), wherein the Bi content is 91.2 to 96.2% by mass.
(3)
The solder alloy according to any one of (1) to (2), wherein the solidus temperature is 235 ° C. or higher.
(4)
The solder alloy according to any one of (1) to (3), wherein the liquidus temperature is 272 ° C. or lower.
(5)
The following formula: [liquidus temperature]-[solidus temperature]
The solder alloy according to any one of (1) to (4), wherein
(6)
The solder alloy according to any one of (1) to (5), wherein the bonding strength after one reflow treatment is 39 MPa or more.
(7)
The solder alloy according to any one of (1) to (6), wherein the bonding strength after three reflow treatments is 39 MPa or more.
(8)
The solder alloy according to any one of (1) to (7), wherein the bonding strength after holding at a high temperature of 250 ° C. for 1000 hours is 40 MPa or more.
(9)
The solder alloy according to any one of (1) to (8), wherein the shape of the solder alloy is a powder, a ball, or a sheet.
(10)
A member made of the solder alloy according to any one of (1) to (8).
(11)
An internal joint solder joint of an electronic component soldered with the solder alloy according to any one of (1) to (8).
(12)
A solder joint of a power transistor soldered with the solder alloy according to any one of (1) to (8).
(13)
A printed circuit board comprising the solder alloy according to any one of (1) to (8).
(14)
An electronic component comprising the solder alloy according to any one of (1) to (8).
(15)
A power transistor comprising the solder alloy according to any one of (1) to (8).
(16)
An electronic device comprising the solder joint according to (11) or (12), the printed circuit board according to (13), the electronic component according to (14), or the power transistor according to (15).
(17)
A power device having the solder joint according to (11) or (12).
　好適な実施の態様において、本願発明は、上記はんだ合金を材料とした部材、上記はんだ合金ではんだ付けされた電子部品の内部接合はんだ継手、上記はんだ合金ではんだ付けされたパワートランジスタのはんだ継手、上記はんだ合金を有するプリント回路板、上記はんだ合金を有する電子部品、上記はんだ合金を有するパワートランジスタを含む。また、好適な実施の態様において、本願発明は、上記のはんだ継手、プリント回路板、電子部品、パワートランジスタを有する電子機器を含み、上記のはんだ継手を有するパワーデバイスを含む。 In a preferred embodiment, the present invention is a member made of the above-mentioned solder alloy, an internal joint solder joint of an electronic component soldered with the solder alloy, a solder joint of a power transistor soldered with the solder alloy, It includes a printed circuit board having the solder alloy, an electronic component having the solder alloy, and a power transistor having the solder alloy. In a preferred embodiment, the present invention includes the above-described solder joint, a printed circuit board, an electronic component, and an electronic device having a power transistor, and includes a power device having the above-described solder joint.
　以下に実施例をあげて、本発明を詳細に説明する。本発明は、以下に例示する実施例に限定されるものではない。 The present invention will be described in detail with reference to the following examples. The present invention is not limited to the embodiments illustrated below.
［実施例１］
　黒鉛るつぼにＢｉ、Ｃｕ、Ｓｎのチップ原料を所定量投入し、黒鉛るつぼをアトマイズ装置にセットし、不活性ガス雰囲気とし、均一に原料が溶解するまで一定時間保持して溶湯を得た。
　その後、黒鉛るつぼの底部に設置されたストッパーを引き上げ、溶湯を下部に投下した。その時不活性ガスを溶湯に吹き付け、はんだ粉を製造した。
　はんだ粉は０．５ｇ正確に秤量し、酸に溶解した後、ＩＣＰ発光分光分析器で濃度を測定し、その結果を表１に記載した。 [Example 1]
A predetermined amount of Bi, Cu, and Sn chip raw materials was charged into a graphite crucible, the graphite crucible was set in an atomizing apparatus, an inert gas atmosphere was maintained, and a predetermined time was maintained until the raw materials were uniformly dissolved to obtain a molten metal.
Thereafter, the stopper installed at the bottom of the graphite crucible was pulled up, and the molten metal was dropped on the lower part. At that time, an inert gas was sprayed on the molten metal to produce a solder powder.
0.5 g of the solder powder was accurately weighed and dissolved in an acid, and then the concentration was measured with an ICP emission spectrometer. The result is shown in Table 1.
［固相線温度、液相線温度、融点の測定］
　はんだ合金の固相線温度（ＳＰＴ）、液相線温度（ＬＰＴ）及び融点（ＭＰ）の測定は、ＪＩＳ　Ｚ３１９８－１：２０１４に準拠し、示差走査熱量測定（ＤＳＣ：Ｄｉｆｆｅｒｅｎｔｉａｌ　Ｓｃａｎｎｉｎｇ　Ｃａｌｏｒｉｍｅｔｒｙ）による方法で実施した。これらの結果をまとめて表１に示す。 [Measurement of solidus temperature, liquidus temperature, melting point]
The measurement of the solidus temperature (SPT), the liquidus temperature (LPT) and the melting point (MP) of the solder alloy is based on JIS Z3198-1: 2014, and is performed by differential scanning calorimetry (DSC). It was carried out in. The results are summarized in Table 1.
［シェア強度の測定（リフロー１回もしくは３回処理後）］
　Ｓｉウエハの片面にスパッタリングにより、Ａｌ面（厚さ３μｍ）を作製し、更に塗布によりポリイミド膜を形成し、その後露光現像によりポリイミド膜に直径３００μｍの開口部のランドを形成した。
　さらに無電解めっきによりランド部の上に、Ｎｉ層（厚さ２．５μｍ）、Ｐｄ層（厚さ０．０５μｍ）、Ａｕ層（厚さ０．０２μｍ）を順次形成してＵＢＭを設けた。
　ＵＢＭの上にフラックスを塗布し、さらにその上に直径３００μｍのはんだ粉を搭載し、リフロー処理を行って、加熱接合させた。リフロー処理の条件は、リフロー温度２９０℃×１分間で行い、これを１回だけ行うか、あるいは３回くり返した。
　その後接合強度（シェア強度）を以下の条件により測定した。
　接合強度は、ＭＩＬ　ＳＴＤ－８８３Ｇに準じて測定した。荷重センサに取り付けられたツールが基板面まで下降し、装置が基板面を検出し下降を停止し、検出した基板面から設定された高さまでツールが上昇し、ツールで接合部を押して破壊時の荷重を計測した。これらの結果をまとめて表１に示す。
＜測定条件＞
　装置：ｄａｇｅ社製　ｄａｇｅ　ｓｅｒｉｅｓ　４０００
　方法：ダイシェアテスト
　テストスピード：１００μｍ／ｓ
　テスト高さ：２０．０μｍ
　ツール移動量：０．９ｍｍ [Measurement of shear strength (after one or three reflow treatments)]
An Al surface (thickness: 3 μm) was formed on one surface of the Si wafer by sputtering, a polyimide film was formed by coating, and then a land having an opening of 300 μm in diameter was formed in the polyimide film by exposure and development.
Further, a Ni layer (2.5 μm in thickness), a Pd layer (0.05 μm in thickness), and an Au layer (0.02 μm in thickness) were sequentially formed on the lands by electroless plating to provide a UBM.
A flux was applied on the UBM, and a solder powder having a diameter of 300 μm was further mounted thereon, subjected to a reflow treatment, and joined by heating. The conditions for the reflow treatment were a reflow temperature of 290 ° C. × 1 minute, and this was performed only once or repeated three times.
Thereafter, the joining strength (shear strength) was measured under the following conditions.
The bonding strength was measured according to MIL STD-883G. The tool attached to the load sensor descends to the substrate surface, the device detects the substrate surface and stops descending, the tool rises to the set height from the detected substrate surface, and the tool presses the joint and breaks at the time of destruction The load was measured. The results are summarized in Table 1.
<Measurement conditions>
Apparatus: dage series 4000 manufactured by dage
Method: Die shear test Test speed: 100 μm / s
Test height: 20.0 μm
Tool travel: 0.9mm
［シェア強度の測定（高温試験後）］
　リフロー処理後（リフロー処理１回）に、高温試験として、空気雰囲気下で、２５０℃で１０００時間保持した後、上記と同様にシェア強度を測定した。これらの結果をまとめて、表１に示す。 [Measurement of shear strength (after high temperature test)]
After the reflow treatment (one time of the reflow treatment), as a high temperature test, the sample was kept at 250 ° C. for 1000 hours in an air atmosphere, and then the shear strength was measured in the same manner as described above. The results are summarized in Table 1.
［実施例２～６］
　実施例１と同様の手順で、はんだ粉を作製し、ＩＣＰ発光分光分析器で濃度を測定し、示差走査熱量測定によって固相線温度、液相線温度及び融点を測定し、さらにリフロー１回処理後、リフロー３回処理後、及び高温試験後のシェア強度を測定した。これらの結果をまとめて表１に示す。 [Examples 2 to 6]
In the same procedure as in Example 1, a solder powder was prepared, the concentration was measured with an ICP emission spectrometer, and the solidus temperature, liquidus temperature, and melting point were measured by differential scanning calorimetry. After the treatment, the shear strength after three reflow treatments and after the high temperature test were measured. The results are summarized in Table 1.
［比較例１～１２］
　実施例１と同様の手順で、はんだ粉を作製し、ＩＣＰ発光分光分析器で濃度を測定し、示差走査熱量測定によって固相線温度、液相線温度及び融点を測定し、さらにリフロー１回もしくは３回処理後と高温試験後のシェア強度を測定した。これらの結果をまとめて表１に示す。 [Comparative Examples 1 to 12]
In the same procedure as in Example 1, a solder powder was prepared, the concentration was measured with an ICP emission spectrometer, and the solidus temperature, liquidus temperature, and melting point were measured by differential scanning calorimetry. Alternatively, the shear strength after the treatment three times and after the high temperature test was measured. The results are summarized in Table 1.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
［結果］
　表１から示されるように、実施例１～６のはんだ合金は、高温試験後（２５０℃で１０００時間経過後）においても、十分なシェア強度を維持していた。 [result]
As shown in Table 1, the solder alloys of Examples 1 to 6 maintained a sufficient shear strength even after the high temperature test (after a lapse of 1000 hours at 250 ° C.).
　表１において、比較例３、６、９、１２はすでにリフロー３回処理後のシェア強度が低すぎるものであった。
　比較例１、２、５、８、１１は固相線温度が低すぎるものであった。そのために、はんだ合金としては不十分であると考えて、シェア強度測定は行わなかった。 In Table 1, in Comparative Examples 3, 6, 9, and 12, the shear strength after three reflow treatments was already too low.
In Comparative Examples 1, 2, 5, 8, and 11, the solidus temperature was too low. Therefore, the shear strength was not measured because it was considered to be insufficient as a solder alloy.
　実施例１は、比較例４と比較すると、Ｃｕ含有量がほぼ同程度であるがＳｎ含有量が異なることによって、高温試験後のシェア強度が大きく向上したものとなっていた。実施例３は、比較例７と比較すると、Ｃｕ含有量がほぼ同程度であるがＳｎ含有量が異なることによって、高温試験後のシェア強度が大きく向上したものとなっていた。実施例５は、比較例１０と比較すると、Ｃｕ含有量がほぼ同程度であるがＳｎ含有量が異なることによって、高温試験後のシェア強度が大きく向上したものとなっていた。 {Circle around (1)} Example 1 had substantially the same Cu content as Comparative Example 4, but had a significantly improved shear strength after a high-temperature test due to a different Sn content. In Example 3, as compared with Comparative Example 7, the Cu content was almost the same, but the Sn content was different, so that the shear strength after the high-temperature test was greatly improved. In Example 5, as compared with Comparative Example 10, the Cu content was almost the same, but the Sn content was different, so that the shear strength after the high-temperature test was greatly improved.
　表１から示されるように、実施例１～６のはんだ合金は、その組成について、一定の規則性ある範囲を満たすようなものとなっていた。この範囲を示す式を以下に示す。以下の式によって示される範囲を、図１に示す。 As shown in Table 1, the solder alloys of Examples 1 to 6 had compositions that satisfy a certain regular range. An equation indicating this range is shown below. The range indicated by the following equation is shown in FIG.
　図１に示されるように、実施例１～６のはんだ合金の組成は、以下の範囲を満たすものとなっていた：
　１．９≦Ｓｎ含有量（質量％）≦４．３
　１．９≦Ｃｕ含有量（質量％）≦４．５
　Ｃｕ含有量（質量％）≦１．５０×Ｓｎ含有量（質量％）－１．００
　Ｃｕ含有量（質量％）≧１．４５×Ｓｎ含有量（質量％）－１．６３ As shown in FIG. 1, the compositions of the solder alloys of Examples 1 to 6 satisfied the following ranges:
1.9 ≦ Sn content (% by mass) ≦ 4.3
1.9 ≦ Cu content (% by mass) ≦ 4.5
Cu content (% by mass) ≦ 1.50 × Sn content (% by mass) −1.00
Cu content (% by mass) ≧ 1.45 × Sn content (% by mass) −1.63
　本発明は、高温域において、優れた特性を有するはんだ合金を提供する。本発明は産業上有用な発明である。 The present invention provides a solder alloy having excellent properties in a high temperature range. The present invention is an industrially useful invention.

Claims (12)

  1. 　Ｓｎ、Ｂｉ、及びＣｕを含有するはんだ合金であって、
    　Ｓｎ含有量が１．９～４．３質量％であり、Ｃｕ含有量が１．９～４．５質量％であり、残部がＢｉ及び不可避不純物であり、Ｓｎ含有量とＣｕ含有量が、以下の式を満たす、はんだ合金：
    　Ｃｕ含有量（質量％）≦１．５０×Ｓｎ含有量（質量％）－１．００
    　Ｃｕ含有量（質量％）≧１．４５×Ｓｎ含有量（質量％）－１．６３     A solder alloy containing Sn, Bi, and Cu,
    The Sn content is 1.9 to 4.3% by mass, the Cu content is 1.9 to 4.5% by mass, the balance is Bi and inevitable impurities, and the Sn content and the Cu content are Solder alloy that satisfies the following formula:
    Cu content (% by mass) ≦ 1.50 × Sn content (% by mass) −1.00
    Cu content (% by mass) ≧ 1.45 × Sn content (% by mass) −1.63
  2. 　Ｂｉ含有量が９１．２～９６．２質量％である、請求項１に記載のはんだ合金。 2. The solder alloy according to claim 1, wherein the Bi content is 91.2 to 96.2% by mass.
  3. 　固相線温度が２３５℃以上である、請求項１に記載のはんだ合金。 The solder alloy according to claim 1, wherein the solidus temperature is 235 ° C or higher.
  4. 　液相線温度が２７２℃以下である、請求項１に記載のはんだ合金。 は ん だ The solder alloy according to claim 1, wherein the liquidus temperature is 272 ° C or lower.
  5. 　次の式：　［液相線温度］－［固相線温度］
    の値が、３３℃以下である、請求項１に記載のはんだ合金。     The following formula: [liquidus temperature]-[solidus temperature]
    2. The solder alloy according to claim 1, wherein a value of the solder alloy is 33 ° C. or less.
  6. 　リフロー１回処理後の接合強度が３９ＭＰａ以上である、請求項１に記載のはんだ合金。 The solder alloy according to claim 1, wherein the bonding strength after one reflow treatment is 39 MPa or more.
  7. 　リフロー３回処理後の接合強度が３９ＭＰａ以上である、請求項１に記載のはんだ合金。 2. The solder alloy according to claim 1, wherein the bonding strength after three reflow treatments is 39 MPa or more.
  8. 　２５０℃１０００時間の高温保持後の接合強度が４０ＭＰａ以上である、請求項１に記載のはんだ合金。 The solder alloy according to claim 1, wherein the bonding strength after holding at a high temperature of 250 ° C for 1000 hours is 40 MPa or more.
  9. 　はんだ合金の形状が、粉状、ボール状、又はシート状である、請求項１～８のいずれかに記載のはんだ合金。 The solder alloy according to any one of claims 1 to 8, wherein the shape of the solder alloy is a powder, a ball, or a sheet.
  10. 　請求項１に記載のはんだ合金ではんだ付けされた電子部品の内部接合はんだ継手。 An internal joint solder joint of an electronic component soldered with the solder alloy according to claim 1.
  11. 　請求項１に記載のはんだ合金ではんだ付けされたパワートランジスタのはんだ継手。 A solder joint of a power transistor soldered with the solder alloy according to claim 1.
  12. 　請求項１０または１１に記載のはんだ継手を有するパワーデバイス。 A power device having the solder joint according to claim 10 or 11.
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JP2011251329A (en) * 2010-06-04 2011-12-15 Sumitomo Metal Mining Co Ltd High-temperature lead-free solder paste
JP2017177122A (en) * 2016-03-28 2017-10-05 住友金属鉱山株式会社 HIGH-TEMPERATURE Pb-FREE SOLDER PASTE AND MANUFACTURING METHOD THEREOF

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