JP7267522B1 - Bonding materials and semiconductor devices - Google Patents

Bonding materials and semiconductor devices Download PDF

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JP7267522B1
JP7267522B1 JP2023508568A JP2023508568A JP7267522B1 JP 7267522 B1 JP7267522 B1 JP 7267522B1 JP 2023508568 A JP2023508568 A JP 2023508568A JP 2023508568 A JP2023508568 A JP 2023508568A JP 7267522 B1 JP7267522 B1 JP 7267522B1
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melting point
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thermal expansion
metal particles
solder
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浩次 山▲崎▼
紀和 境
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Mitsubishi Electric Corp
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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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
    • H01L23/40—Mountings or securing means for detachable cooling or heating arrangements ; fixed by friction, plugs or springs

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Abstract

第１対象物（２）と第２対象物（３）とを接合する、接合部材（１）。接合部材（１）は、Ｎｉを主成分として含む金属粒子（１１）と、Ｓｎを主成分として含み３００℃未満の融点を有する低融点相（１２）と、Ｓｎと金属粒子（１１）との間の相互拡散により生じた３００℃以上の融点を有する金属間化合物（１３）と、を含む。接合部材（１）の総量に対する低融点相（１２）の量の比率は２体積％以上２０体積％未満である。第１対象物（２）および第２対象物（３）の熱膨張係数は３×１０－６／Ｋ以上１３×１０－６／Ｋ未満であり、第１対象物（２）と第２対象物（３）との間の熱膨張係数の差は５×１０－６／Ｋ未満である。接合部材（１）の熱膨張係数は１６×１０－６／Ｋ以上２０×１０－６／Ｋ未満である。A joining member (1) for joining a first object (2) and a second object (3). The joining member (1) is composed of metal particles (11) containing Ni as a main component, a low melting point phase (12) containing Sn as a main component and having a melting point of less than 300° C., and Sn and the metal particles (11). and an intermetallic compound (13) having a melting point of 300° C. or higher generated by interdiffusion between the metals. The ratio of the amount of the low melting point phase (12) to the total amount of the joining member (1) is 2% by volume or more and less than 20% by volume. The thermal expansion coefficients of the first object (2) and the second object (3) are 3 × 10-6 / K or more and less than 13 × 10-6 / K, and the first object (2) and the second object The difference in coefficient of thermal expansion between object (3) is less than 5×10 −6 /K. The joining member (1) has a thermal expansion coefficient of 16×10 −6 /K or more and less than 20×10 −6 /K.

Description

本開示は、接合部材および半導体装置に関する。 The present disclosure relates to bonding members and semiconductor devices.

近年、半導体装置に対する信頼性の要求はますます高まっている。特に、熱膨張係数の異なる部品の接合部（例えば、半導体素子と回路基板との接合部、または、回路基板と放熱板との接合部）についての寿命信頼性の向上が求められている。 In recent years, the demand for reliability of semiconductor devices is increasing more and more. In particular, there is a demand for improving the life reliability of joints between parts having different coefficients of thermal expansion (for example, joints between a semiconductor element and a circuit board, or joints between a circuit board and a heat sink).

従来、シリコン（Ｓｉ）、ガリウム砒素（ＧａＡｓ）等を用いた基材を有する半導体素子が多く使われている。そのような半導体素子の動作温度は１００℃～１２５℃である。それらの半導体素子と回路基板との接合に用いられるはんだ材には、製造時の多段階はんだ接合に対応するための高融点、起動と停止に伴う繰り返し熱応力に対する耐クラック性、および、デバイスの汚染耐性が求められる。 2. Description of the Related Art Conventionally, many semiconductor devices having substrates using silicon (Si), gallium arsenide (GaAs), or the like have been used. The operating temperature of such semiconductor devices is 100.degree. C. to 125.degree. The solder materials used to join these semiconductor elements and circuit boards must have a high melting point to support multi-step solder joints during manufacturing, crack resistance against repeated thermal stress associated with starting and stopping, and Contamination resistance is required.

それら要求に対して、例えば、Ｓｉデバイス用のはんだ材として９５Ｐｂ－５Ｓｎ（質量％）が使用され、ガリウム砒素デバイス用のはんだ材として８０Ａｕ－２０Ｓｎ（質量％）が使用されてきた。 To meet these requirements, for example, 95Pb-5Sn (mass %) has been used as a solder material for Si devices, and 80Au-20Sn (mass %) has been used as a solder material for gallium arsenide devices.

しかしながら、有害な鉛（Ｐｂ）を大量に含有する９５Ｐｂ－５Ｓｎは、環境負荷低減の観点から問題がある。また、貴金属を多く含む８０Ａｕ－２０Ｓｎは、貴金属の価格高騰または埋蔵量の点から問題がある。したがって、両者について代替材が強く望まれていた。 However, 95Pb-5Sn, which contains a large amount of harmful lead (Pb), poses a problem from the viewpoint of reducing the environmental load. In addition, 80Au-20Sn, which contains a large amount of precious metals, poses a problem in terms of rising precious metal prices or reserves. Therefore, alternative materials for both have been strongly desired.

一方、省エネルギーの観点から、次世代デバイスとしてシリコンカーバイド（ＳｉＣ）または窒化ガリウム（ＧａＮ）を用いた基材を有するデバイスの開発が盛んになされている。これらの動作温度は、１７５℃以上とされており、将来的には３００℃になるとも言われている。 On the other hand, from the viewpoint of energy saving, as next-generation devices, devices having substrates using silicon carbide (SiC) or gallium nitride (GaN) are being actively developed. The operating temperature of these devices is 175° C. or higher, and is said to reach 300° C. in the future.

これは、半導体素子と回路基板との接合部の温度が１７５℃になることを意味する。また、回路基板と放熱板との接合部の温度も、動作条件および放熱性能によっては、これに近い温度まで上昇する。このため、半導体素子と回路基板との接合部とともに、回路基板と放熱板との接合部には、高い信頼性が求められている。 This means that the temperature of the junction between the semiconductor element and the circuit board reaches 175.degree. In addition, the temperature of the joint between the circuit board and the heat sink also rises to a temperature close to this depending on the operating conditions and heat dissipation performance. Therefore, high reliability is required for the joint between the circuit board and the heat sink as well as the joint between the semiconductor element and the circuit board.

上記のように、従来および次世代のデバイスにおいて、融点が高く、かつ耐熱性に優れた上記接合部を構造する部材（接合部材）が求められている。 As described above, in conventional and next-generation devices, there is a demand for a member (joining member) that has a high melting point and excellent heat resistance and that forms the joining portion.

従来の高耐熱な接合体の製造方法として、Ｓｎ中にＡｇ、Ｃｕ等の金属粒子を多く添加して、接合時の加熱（３００℃以下）による金属拡散によって、接合層をＡｇ－Ｓｎ合金相（例えば、Ａｇ３Ｓｎ：融点４８０℃）、Ｃｕ－Ｓｎ合金（例えば、Ｃｕ６Ｓｎ５：融点４１５℃、Ｃｕ３Ｓｎ：融点６７６℃）等で形成する方法が知られている。As a conventional method for manufacturing a highly heat-resistant bonded body, a large amount of metal particles such as Ag and Cu are added to Sn, and the bonding layer is formed into an Ag—Sn alloy phase by metal diffusion due to heating (300 ° C. or less) during bonding. (for example, Ag 3 Sn: melting point 480° C.), Cu—Sn alloy (for example, Cu 6 Sn 5 : melting point 415° C., Cu 3 Sn: melting point 676° C.), and the like.

例えば、特許文献１（特開２００２－３１４２４１号公報）では、はんだを用いた接続方法または電子機器に関して、はんだボールのＳｎが溶融して、金属ボールのＣｕとの界面で金属間化合物を形成し、Ｃｕの金属ボール間が連結された接合構造が開示されている。なお、溶融したＳｎは、半導体チップの電極、中間基板の電極等とも金属間化合物を形成するため、Ｃｕの金属ボールとそれらの電極とが連結されている。 For example, in Patent Document 1 (Japanese Patent Application Laid-Open No. 2002-314241), regarding a connection method or an electronic device using solder, Sn in a solder ball melts to form an intermetallic compound at the interface with Cu in the metal ball. , Cu metal balls are connected. The molten Sn also forms an intermetallic compound with the electrodes of the semiconductor chip, the electrodes of the intermediate substrate, and the like, so that the metal balls of Cu and these electrodes are connected.

また、接続部は、はんだボールのＳｎがＣｕ－Ｓｎ金属間化合物（Ｃｕ６Ｓｎ５、融点：約６３０℃）となって、接触部およびその近傍は高融点化し、たとえＳｎの一部が残っても、他の部分が溶融しなければ、後付けのはんだ接続時のプロセスに耐えられる強度を十分に確保できると、特許文献１に記載されている。In addition, the Sn of the solder ball at the connection portion becomes a Cu—Sn intermetallic compound (Cu 6 Sn 5 , melting point: about 630° C.), and the contact portion and its vicinity have a high melting point, even though some Sn remains. Patent document 1 states that, even if other parts do not melt, sufficient strength can be ensured to withstand the process of soldering for later attachment.

なお、金属ボールとして、Ｃｕに限らず、Ａｇ、Ａｕ、Ａｌ、Ｎｉ、Ｃｕ合金、Ｃｕ－Ｓｎ化合物、Ａｇ－Ｓｎ化合物、Ａｕ－Ｓｎ化合物、Ａｌ－Ａｇ化合物、Ｚｎ－Ａｌ化合物などを用いても良く、Ａｕはぬれ性が良いために接続部のボイド低減効果を有する旨も、特許文献１に記載されている。 The metal balls are not limited to Cu, and Ag, Au, Al, Ni, Cu alloys, Cu—Sn compounds, Ag—Sn compounds, Au—Sn compounds, Al—Ag compounds, Zn—Al compounds, etc. can be used. Patent Document 1 also states that Au has good wettability and therefore has an effect of reducing voids in the connection portion.

また、特許文献２（国際公開第２０１２／１０８３９５号）では、接続部において、Ｓｎ系金属とＣｕ系金属を含むはんだを加熱溶融することにより、３１０℃以上の融点を持つ金属間化合物が形成されることが記載されている。なお、接続部に含まれるＳｎ系金属成分の比率が３０体積％以下であることも開示されている。 Further, in Patent Document 2 (International Publication No. 2012/108395), an intermetallic compound having a melting point of 310° C. or higher is formed by heating and melting a solder containing Sn-based metal and Cu-based metal in a connection portion. It is stated that It is also disclosed that the ratio of the Sn-based metal component contained in the connecting portion is 30% by volume or less.

特開２００２－３１４２４１号公報JP-A-2002-314241 国際公開第２０１２／１０８３９５号WO2012/108395

しかし、特許文献１および特許文献２に示されている従来の半導体装置の製造方法では、Ｓｎ粒子に対する金属粒子の添加量について、熱衝撃試験でのクラック耐性に関する評価はなされていない。 However, in the conventional semiconductor device manufacturing methods disclosed in Patent Documents 1 and 2, the amount of metal particles added to Sn particles is not evaluated with respect to crack resistance in a thermal shock test.

例えば、Ｃｕ粒子、Ａｇ粒子等の金属粒子を多く添加すると、Ｓｎの流動性が悪くなるため、金属粒子同士で密閉された箇所は未接合部となり、ボイドが発生し、接合部に熱衝撃が加わった際にクラックが生じ易い。 For example, when a large amount of metal particles such as Cu particles and Ag particles are added, the flowability of Sn deteriorates, so the parts sealed between the metal particles become unjoined parts, voids are generated, and thermal shock is applied to the joint parts. Cracks are likely to occur when applied.

加えて、Ａｇ３Ｓｎに代表されるＡｇ－Ｓｎ合金、または、Ｃｕ６Ｓｎ５に代表されるＣｕ－Ｓｎ合金は、金属状態図から考えると、５質量％程度のＡｇまたはＣｕとＳｎとの固溶領域を有する。しかし、２相分離型の様相を示すため、Ａｇ３ＳｎとＣｕ６Ｓｎ５との界面は、低融点のＳｎ相が無ければ空隙となり、クラックの起点となる。In addition, Ag—Sn alloys typified by Ag 3 Sn, or Cu—Sn alloys typified by Cu 6 Sn 5 , have about 5% by mass of Ag or Cu and Sn, considering the metal phase diagram. It has a solid solution region. However, since it exhibits a two-phase separation type appearance, the interface between Ag 3 Sn and Cu 6 Sn 5 becomes a void if there is no Sn phase with a low melting point, and becomes a starting point of cracks.

一方、本発明者らは、高温動作する半導体装置においては、材料としての機械特性、または、適用した部品単体としての耐ヒートサイクル性だけではなく、実際の動作を伴うパワーサイクル（半導体装置に対して電力印加のＯＮとＯＦＦを繰り返すことで発熱と冷却を繰り返すこと）における装置としての信頼性を確保することが重要であると考えた。 On the other hand, in semiconductor devices that operate at high temperatures, the present inventors consider not only the mechanical properties of the material or the heat cycle resistance of the individual parts to which they are applied, but also the power cycle that accompanies the actual operation (for semiconductor devices, It is important to ensure the reliability of the device in the case of repeating heat generation and cooling by repeatedly turning on and off the application of electric power.

本開示の目的は、高温動作する半導体装置において、パワーサイクルに対する接合信頼性の高い接合部材を提供することである。 An object of the present disclosure is to provide a bonding member with high bonding reliability against power cycles in a semiconductor device that operates at high temperatures.

第１対象物と第２対象物とを接合する、接合部材。
接合部材は、Ｎｉを主成分として含む金属粒子と、Ｓｎを主成分として含み３００℃未満の融点を有する低融点相と、Ｓｎと前記金属粒子との間の相互拡散により生じた３００℃以上の融点を有する金属間化合物と、を含む。
前記接合部材の総量に対する前記低融点相の量の比率は２体積％以上２０体積％未満である。
前記第１対象物および前記第２対象物の熱膨張係数は３×１０－６／Ｋ以上１３×１０－６／Ｋ未満であり、前記第１対象物と前記第２対象物との間の熱膨張係数の差は５×１０－６／Ｋ未満である。
前記接合部材の熱膨張係数は１６×１０－６／Ｋ以上２０×１０－６／Ｋ未満である。A joining member that joins the first object and the second object.
The joining member includes metal particles containing Ni as a main component, a low melting point phase containing Sn as a main component and having a melting point of less than 300° C., and a temperature of 300° C. or higher generated by interdiffusion between Sn and the metal particles. and an intermetallic compound having a melting point.
A ratio of the amount of the low melting point phase to the total amount of the joining member is 2% by volume or more and less than 20% by volume.
The coefficient of thermal expansion of the first object and the second object is 3×10 −6 /K or more and less than 13×10 −6 /K, and the thermal expansion coefficient between the first object and the second object is The difference in thermal expansion coefficients is less than 5×10 −6 /K.
The thermal expansion coefficient of the joining member is 16×10 −6 /K or more and less than 20×10 −6 /K.

本開示によれば、高温動作する半導体装置において、パワーサイクルに対する接合信頼性の高い接合部材を提供することができる。 According to the present disclosure, it is possible to provide a bonding member with high bonding reliability against power cycles in a semiconductor device that operates at high temperatures.

具体的には、本開示の接合部材では、低融点相（例えば、Ｓｎ単独相）を残存させることで、被接合部材（接合対象物）への濡れ性を確保し、その残存量を適正化することで、パワーサイクルにおける縦クラックを抑制することができる。 Specifically, in the bonding member of the present disclosure, by leaving a low melting point phase (for example, a single Sn phase), the wettability to the member to be bonded (bonded object) is ensured, and the remaining amount is optimized. By doing so, vertical cracks in power cycles can be suppressed.

また、本開示の接合部材は、熱膨張係数差が特定の範囲内である複数の接合対象物の接合に適用されるため、複数の接合対象物間の熱膨張係数差に起因するせん断応力によって生じる横クラックを抑制することができる。 In addition, since the joining member of the present disclosure is applied to joining a plurality of objects to be joined having a difference in thermal expansion coefficient within a specific range, the shear stress caused by the difference in thermal expansion coefficient between the plurality of objects to be joined Horizontal cracks that occur can be suppressed.

更に、特定の範囲内の熱膨張係数を有する接合部材を採用することで、接合対象物と接合部材との間の熱膨張係数差に起因する引張応力および圧縮応力（引張圧縮応力）が抑制され、高温（例えば、１７５℃）での動作においても優れた接合信頼性を有する。 Furthermore, by adopting joining members having a coefficient of thermal expansion within a specific range, tensile stress and compressive stress (tensile-compressive stress) caused by the difference in coefficient of thermal expansion between the object to be joined and the members to be joined can be suppressed. , and has excellent bonding reliability even during operation at high temperatures (eg, 175° C.).

半導体装置（接合部材）の製造手順を示すフローチャートである。4 is a flow chart showing a manufacturing procedure of a semiconductor device (joining member). 図１の第１工程を示す概略断面図である。It is a schematic sectional drawing which shows the 1st process of FIG. 図１の第２工程を示す概略断面図である。It is a schematic sectional drawing which shows the 2nd process of FIG. 図１の第３工程を示す概略断面図である。It is a schematic sectional drawing which shows the 3rd process of FIG. 図１の第４工程を示す概略断面図である。It is a schematic sectional drawing which shows the 4th process of FIG. 図１の第５工程を示す概略断面図である。It is a schematic sectional drawing which shows the 5th process of FIG.

以下、本開示の実施の形態について説明する。なお、図面において、長さ、幅、厚さ、深さなどの寸法関係は図面の明瞭化と簡略化のために適宜変更されており、実際の寸法関係を表すものではない。 Embodiments of the present disclosure will be described below. In the drawings, dimensional relationships such as length, width, thickness, and depth are changed as appropriate for clarity and simplification of the drawings, and do not represent actual dimensional relationships.

実施の形態１．
＜接合部材＞
本実施の形態の接合部材１は、第１対象物２（例えば、放熱板）と第２対象物３（例えば、半導体素子および配線回路を有する回路基板）とを接合する部材である（図６参照）。なお、接合部材１は、後述のはんだシート１０とは異なり、加熱工程により溶融した後に凝固したはんだ（はんだ合金）からなる部材であり、被接合部材（第１対象物２および第２対象物３）の両者と接合した状態で存在する部材である。Embodiment 1.
<Joining member>
The joining member 1 of the present embodiment is a member that joins a first object 2 (for example, a radiator plate) and a second object 3 (for example, a circuit board having a semiconductor element and a wiring circuit) (FIG. 6 reference). In addition, unlike the solder sheet 10 described later, the joining member 1 is a member made of solder (solder alloy) that is solidified after being melted in a heating process, and is a member to be joined (the first object 2 and the second object 3 ) is a member that exists in a state of being joined to both.

本実施の形態の接合部材１は、金属粒子１１と、低融点相１２と、金属間化合物１３と、を含む。 Joining member 1 of the present embodiment includes metal particles 11 , low melting point phase 12 , and intermetallic compound 13 .

金属粒子１１は、Ｎｉを主成分として含む。ここで、「主成分」とは、金属粒子１１に含まれる成分のうち最も量が多い成分である。金属粒子１１中のＳｎの含有率は、好ましくは６０質量％以上であり、より好ましくは７０質量％以上であり、さらに好ましくは８０質量％以上である。 Metal particles 11 contain Ni as a main component. Here, the “main component” is the component contained in the metal particles 11 in the largest amount. The Sn content in metal particles 11 is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more.

金属粒子１１は、さらに、Ｆｅ、Ｃｒ、Ｃ、ＣｕおよびＳｉからなる群から選択される少なくとも１種の成分を含み得る。 Metal particles 11 may further contain at least one component selected from the group consisting of Fe, Cr, C, Cu and Si.

低融点相１２は、Ｓｎを主成分として含み、３００℃未満の融点を有する。ここで、「主成分」とは、低融点相１２に含まれる成分のうち最も量が多い成分である。低融点相１２中のＳｎの含有率は、好ましくは６０質量％以上であり、より好ましくは７０質量％以上であり、さらに好ましくは８０質量％以上である。 The low melting point phase 12 contains Sn as a main component and has a melting point of less than 300°C. Here, the “main component” is the component contained in the low-melting phase 12 in the largest amount. The Sn content in the low melting point phase 12 is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more.

低融点相は、例えば、（Ｓｎに加えて）さらにＡｇおよびＣｕを含み得る。この場合、例えば、Ａｇの含有率は３質量％以上４質量％未満であってもよく、Ｃｕの含有率は０．５質量％以上１．０質量％未満であってもよい。なお、ＡｇおよびＣｕの含有率がこの範囲内であれば、本開示の効果がより確実に得られることが期待される。 The low-melting phase may, for example, also contain Ag and Cu (in addition to Sn). In this case, for example, the Ag content may be 3% by mass or more and less than 4% by mass, and the Cu content may be 0.5% by mass or more and less than 1.0% by mass. If the Ag and Cu contents are within this range, it is expected that the effects of the present disclosure will be obtained more reliably.

金属間化合物１３は、Ｓｎと金属粒子１１との間の相互拡散により生じた化合物（相）であり、３００℃以上の融点を有する。 The intermetallic compound 13 is a compound (phase) produced by interdiffusion between Sn and the metal particles 11, and has a melting point of 300° C. or higher.

また、本実施の形態の接合部材１において、接合部材１の総量に対する低融点相１２の量の比率は、２体積％以上２０体積％未満である。 Moreover, in the bonding member 1 of the present embodiment, the ratio of the amount of the low melting point phase 12 to the total amount of the bonding member 1 is 2% by volume or more and less than 20% by volume.

また、第１対象物２および第２対象物３の熱膨張係数は、３×１０－６／Ｋ以上１３×１０－６／Ｋ未満であり、かつ、第１対象物２と第２対象物３との間の熱膨張係数の差は５×１０－６／Ｋ未満である。In addition, the thermal expansion coefficients of the first object 2 and the second object 3 are 3 × 10 -6 /K or more and less than 13 × 10 -6 /K, and the first object 2 and the second object 3 is less than 5×10 −6 /K.

また、接合部材の熱膨張係数は、１６×１０－６／Ｋ以上２０×１０－６／Ｋ未満である。Also, the thermal expansion coefficient of the bonding member is 16×10 −6 /K or more and less than 20×10 −6 /K.

なお、本発明者らは、半導体装置に対してパワーサイクルでの信頼性試験を行った結果、パワーサイクルでは、接合部材の層に対して厚み方向に生じるクラック（縦クラック）の抑制が、接合信頼性の向上に重要であることを見出した。 The inventors of the present invention conducted a reliability test on a semiconductor device under power cycling, and found that the suppression of cracks (longitudinal cracks) generated in the thickness direction of the layers of the bonding member during power cycling was effective for bonding. It was found to be important for improving reliability.

さらに、はんだ等の接合部材を構成する材料だけではなく、被接合部材（接合対象物）の構成によっても、接合部の信頼性は左右される。このため、パワーモジュールの信頼性を高めるためには、接合部材の材料の組成だけでなく、被接合部材の構成も併せた検討が必要であると考えられる。 Furthermore, the reliability of the joint is influenced not only by the material such as solder that constitutes the joint member, but also by the structure of the member to be joined (object to be joined). Therefore, in order to improve the reliability of the power module, it is considered necessary to consider not only the composition of the material of the joining members but also the configuration of the members to be joined.

なお、この縦クラックについて、参考文献（山崎浩次，“鉛フリーはんだ接合部の縦割れ発生条件に関する研究”，第２６回エレクトロニクス実装学術講演大会，９Ｃ－１４）には、Ｃｕ板同士をはんだ接合したサンプル、および、Ｍｏ板同士をはんだ接合したサンプルに対して、高速ヒートサイクル試験（＋５０℃／＋１７５℃、温度差：１２５℃）を実施したところ、どちらも同じはんだ材を用いて接合されているにも関わらず、前者では縦クラックが発生せず、後者では縦クラックが発生したことが記載されている。 Regarding this vertical crack, the reference (Koji Yamazaki, "Study on Conditions for Vertical Crack Occurrence in Lead-Free Solder Joints", 26th Electronics Packaging Academic Lecture Conference, 9C-14) mentions that Cu plates are soldered together. When a high-speed heat cycle test (+50°C/+175°C, temperature difference: 125°C) was performed on the sample that was soldered together and the sample that was soldered together, both were joined using the same solder material. It is described that the former did not generate vertical cracks and the latter generated vertical cracks, despite the presence of the cracks.

これには、はんだ材と被接合部材との熱膨張係数差に起因する引張応力および圧縮応力（引張圧縮応力）が関係している。低熱膨張性の部材で拘束されると熱膨張係数の大きいはんだには引張圧縮応力がかかり、更に加熱のよってはんだに動的再結晶が生じることで、はんだの主成分であるＳｎの粒界または内部析出物伝いに縦クラックが発生する。 This is related to tensile stress and compressive stress (tensile-compressive stress) caused by the difference in thermal expansion coefficient between the solder material and the member to be joined. When restrained by a member with low thermal expansion, tensile compressive stress is applied to the solder with a large thermal expansion coefficient, and dynamic recrystallization occurs in the solder due to heating. Vertical cracks are generated along the internal precipitates.

なお、被接合部材間（２つの接合対象物の間）で熱膨張係数差が大きい場合は、縦クラックではなく、横クラックが主に発生することが知られている。 It is known that when there is a large difference in thermal expansion coefficients between members to be joined (two objects to be joined), not vertical cracks but horizontal cracks are mainly generated.

本発明者らは、上述のような検討の結果によって、高温動作する半導体装置におけるパワーサイクルに対する接合信頼性の高い本開示の接合部材を見出した。 As a result of the studies described above, the present inventors have found the bonding member of the present disclosure that has high bonding reliability against power cycles in semiconductor devices that operate at high temperatures.

実施の形態２．
＜半導体装置＞
本実施の形態に係る半導体装置は、放熱板２と、回路基板３（半導体素子および配線回路を有する基板）と、を備える。放熱板２と回路基板３とは、実施の形態１に記載の接合信頼製の高い接合部材１を介して接合されている。これにより、信頼性の高い半導体装置が提供される。Embodiment 2.
<Semiconductor device>
The semiconductor device according to the present embodiment includes a radiator plate 2 and a circuit board 3 (a board having semiconductor elements and wiring circuits). The radiator plate 2 and the circuit board 3 are bonded via the bonding member 1 described in the first embodiment, which has high bonding reliability. Thereby, a highly reliable semiconductor device is provided.

本実施の形態の半導体装置は、放熱板と回路基板とを接合する工程（図１～図６参照）を含む製造方法によって、製造され得る。 The semiconductor device of this embodiment can be manufactured by a manufacturing method including a step of bonding a heat sink and a circuit board (see FIGS. 1 to 6).

以下、図１に示されるフローチャートを参照して、本実施の形態の半導体装置の製造方法において、回路基板と放熱板を接合する際の手順の一例について、説明する。 An example of a procedure for bonding a circuit board and a heat sink in the method of manufacturing a semiconductor device according to the present embodiment will be described below with reference to the flowchart shown in FIG.

最初に、第１工程（Ｓ１）として、Ｓｎを主成分として含み３００℃以下の融点を有する低融点相１２中に、Ｎｉからなる金属粒子１１が分散されてなる、はんだシート１０を所定のサイズにカットする（図２参照）。 First, as a first step (S1), a solder sheet 10 having a metal particle 11 made of Ni dispersed in a low-melting phase 12 containing Sn as a main component and having a melting point of 300° C. or less is prepared to a predetermined size. (see Figure 2).

具体的には、低融点相１２のはんだ組成の代表例としてＳｎ－３．３Ａｇ－０．５Ｃｕ（数値は質量％を示す。Ｓｎは他の元素の組成比の残部である。）で示される組成となるように各元素を添加し溶解して、バルク体を作製した。 Specifically, Sn-3.3Ag-0.5Cu (numerical values indicate % by mass. Sn is the remainder of the composition ratio of other elements) as a representative example of the solder composition of the low melting point phase 12. A bulk body was produced by adding and dissolving each element so as to obtain the composition.

次に、厚みが１００μｍになるように、１００℃以下の圧延プロセスにより、ロール状のはんだシート１０を作製した。 Next, a roll-shaped solder sheet 10 was produced by a rolling process at 100° C. or less so as to have a thickness of 100 μm.

その後、Ｎｉ粒子（金属粒子１１）をはんだシート１０内に均一に分散し、更に上から低融点相１２からなるシートを重ねあわせて混合シートを作製した。本実施の形態では１００μｍ厚としたが、これに依らない。またカットサイズは上部材と同じサイズ１０ｍｍ×１０ｍｍにカットした。 After that, Ni particles (metallic particles 11) were uniformly dispersed in the solder sheet 10, and a sheet composed of the low-melting phase 12 was overlaid to prepare a mixed sheet. In this embodiment, the thickness is set to 100 μm, but it does not depend on this. Also, the cut size was the same size as the upper member, 10 mm×10 mm.

なお、はんだシート１０の製造については、圧延だけでなく、バルク体を溶融させて薄いスリットから溶けたはんだを順次流し込むことにより、はんだシート１０を製造してもよい。また、上記のように元素の組み合わせが３元素より多い場合（例えばＳｎ－Ａｇ－ＣｕにＢｉ、Ｉｎ、Ｓｂ等を添加する場合）、溶解炉の温度バラつきによって、バルク体の組成が不均一になる場合がある。その場合はＳｎ－Ａｇ－Ｃｕのバルク体を最初に製造し、その後再度溶解させて残りのＢｉ、Ｉｎ、Ｓｂ等を所定量添加することではんだ組成の調整をしてもよい。他に、一旦はんだボール化して、そのはんだボールを均一に平板にばらまき、圧縮成型してはんだシート１０を製造してもよい。 The solder sheet 10 may be manufactured not only by rolling, but also by melting a bulk body and sequentially pouring the melted solder through thin slits. In addition, when the combination of elements is more than three elements as described above (for example, when Bi, In, Sb, etc. are added to Sn-Ag-Cu), the composition of the bulk body becomes uneven due to temperature variations in the melting furnace. may become. In that case, a Sn--Ag--Cu bulk body may be manufactured first, then melted again, and the remaining Bi, In, Sb, etc. may be added in predetermined amounts to adjust the solder composition. Alternatively, the solder sheet 10 may be manufactured by forming solder balls once, spreading the solder balls uniformly on a flat plate, and performing compression molding.

次に、第２工程（Ｓ２）として、第１対象物２（下部材）に上記はんだシート１０を載せる（図３参照）。 Next, as a second step (S2), the solder sheet 10 is placed on the first object 2 (lower member) (see FIG. 3).

なお、ＣｕＭｏ合金板の最表面には、酸化防止のため、接合性に影響を与えない分解温度１００℃以下の防錆剤を所定量塗布してもよい。また、はんだシート１０を載せる際、はんだシート１０が所定位置からズレないように１００℃以上の高温で熱分解する有機剤をタック材として使用してもよい。タック材の粘度としては２００Ｐａ・ｓ以上が好ましい。あるいは、はんだシート１０がズレない様に第１対象物２の接合部以外にはレジスト膜を塗布しておけばよい。 In order to prevent oxidation, the outermost surface of the CuMo alloy plate may be coated with a predetermined amount of an antirust agent having a decomposition temperature of 100° C. or less, which does not affect the bondability. Also, when placing the solder sheet 10, an organic agent that thermally decomposes at a high temperature of 100° C. or higher may be used as a tack material so that the solder sheet 10 does not shift from a predetermined position. The viscosity of the tack material is preferably 200 Pa·s or more. Alternatively, a resist film may be applied to areas other than the joints of the first object 2 so that the solder sheet 10 is not displaced.

はんだシート１０については、カット時あるいはハンドリング時に多少の湾曲が生じていてもよい。これは、はんだシート１０が加熱によってある程度溶融するので、はんだシートの初期形状による影響が小さいためである。ただし、次工程で第２対象物３（上部材）を載せるため、第２対象物３（上部材）を載せられない程、はんだシート１０が大きく湾曲している場合は、はんだシート１０を別の平板上で平行に矯正する。 The solder sheet 10 may be slightly curved during cutting or handling. This is because the solder sheet 10 is melted to some extent by heating, so that the initial shape of the solder sheet has little effect. However, since the second object 3 (upper member) is to be placed in the next process, if the solder sheet 10 is curved so much that the second object 3 (upper member) cannot be placed, the solder sheet 10 must be removed. straighten on a flat plate.

次に、第３工程（Ｓ３）として、第２対象物３（上部材）をはんだシート１０上に載せる（図４参照）。 Next, as a third step (S3), the second object 3 (upper member) is placed on the solder sheet 10 (see FIG. 4).

なお、被接合部材（上部材）１とはんだシート１０との間に、搭載位置を固定させるため上述のタック材を塗布してもよい。 In addition, the tack material described above may be applied between the member to be joined (upper member) 1 and the solder sheet 10 to fix the mounting position.

なお、被接合部材（第１対象物２および第２対象物３）の接合側の表面は、（めっき）はＣｕまたはＮｉのめっきが施されているか、または、数十ｎｍオーダのＡｕ膜、Ａｇ膜、Ｐｔ膜等で被覆されていることが好ましい。 The surfaces of the members to be joined (the first object 2 and the second object 3) on the joining side are (plated) plated with Cu or Ni, or an Au film on the order of several tens of nanometers, It is preferably covered with an Ag film, Pt film, or the like.

次に、第４工程（Ｓ４）として、上記の工程で得られた各部材の積層体を、加熱炉５内のホットプレート５上に載置した（図５参照）。そして、加熱炉５内に酸化膜を還元できる代表的な有機酸であるギ酸を封入し、１８０℃で５分間の加熱、および、その後の２６０℃で３分間の加熱により、はんだシート１０を溶融させて、接合部材１を形成した。 Next, as a fourth step (S4), the laminate of the members obtained in the above steps was placed on the hot plate 5 in the heating furnace 5 (see FIG. 5). Then, formic acid, which is a representative organic acid capable of reducing an oxide film, is enclosed in the heating furnace 5, and the solder sheet 10 is melted by heating at 180° C. for 5 minutes and then at 260° C. for 3 minutes. Then, the joining member 1 was formed.

ここで、はんだシート１０内の低融点相１２と金属粒子１１は熱拡散により化合物を形成する。金属粒子１１の粒径および添加量によって、金属粒子１１とＳｎとの化合物（金属間化合物）の形成割合は変化する。このため、低融点相１２が残るように、金属粒子１１の粒径および添加量を調整することが好ましい。 Here, the low melting point phase 12 and the metal particles 11 in the solder sheet 10 form a compound by thermal diffusion. The formation ratio of the compound (intermetallic compound) between the metal particles 11 and Sn changes depending on the particle size of the metal particles 11 and the amount of addition. Therefore, it is preferable to adjust the particle diameter and the amount of addition of the metal particles 11 so that the low melting point phase 12 remains.

その理由について、まず、接合部材１の多くの部分が金属粒子１１および金属間化合物１３で形成されていれば、低融点相１２のＳｎが変形することができないため、接合信頼性の点では問題がない。 As for the reason, first, if most of the bonding member 1 is formed of the metal particles 11 and the intermetallic compound 13, the Sn of the low-melting-point phase 12 cannot be deformed. There is no

一方、汎用の被接合部材（第１対象物２および第２対象物３）の表面には粗さがあり、表面粗さ（凹凸）が数μｍオーダである場合もあり得る。このため、無加圧で接合する際に、その表面の凹凸の体積分も低融点相１２が濡れ広がる必要がある。しかし、金属粒子１１が多量に存在すると、はんだシート１０内で金属粒子１１の表面積が大きくなり、低融点相１２が金属粒子１１と優先的に反応してしまい、低融点相１２が被接合部材の表面に十分に濡れなくなってしまう。 On the other hand, the general-purpose members to be joined (the first object 2 and the second object 3) have rough surfaces, and the surface roughness (unevenness) may be on the order of several μm. Therefore, when joining without pressure, the low melting point phase 12 needs to wet and spread by the volume of the unevenness on the surface. However, when a large amount of metal particles 11 are present, the surface area of metal particles 11 in solder sheet 10 increases, and low melting point phase 12 preferentially reacts with metal particles 11, causing low melting point phase 12 to become a member to be joined. It will not wet the surface sufficiently.

このため、本実施の形態では、低融点相１２が残るように、金属粒子１１の粒径および添加量を調整することが好ましい。例えば、はんだシート１０に添加される金属粒子１１の粒径（平均粒径：Ｄ５０）は、５～２０μｍであり、はんだシート１０中の金属粒子の配合率は、８～３０質量％である。 Therefore, in the present embodiment, it is preferable to adjust the particle size and the amount of metal particles 11 added so that the low melting point phase 12 remains. For example, the particle size (average particle size: D50) of the metal particles 11 added to the solder sheet 10 is 5-20 μm, and the mixing ratio of the metal particles in the solder sheet 10 is 8-30 mass %.

なお、被接合部材へのダメージが懸念されない場合は、加圧を加えて接合をおこなってもよい。 If there is no concern about damage to the member to be joined, the joining may be performed by applying pressure.

次に、第５工程（Ｓ５）として、接合部材１が形成された試料を冷却プレート６上に置き、冷却をおこなった（図６参照）。 Next, as a fifth step (S5), the sample with the bonding member 1 formed thereon was placed on the cooling plate 6 and cooled (see FIG. 6).

この際、通常のはんだのように完全溶融する材料ではんだ接合部材が形成される場合、熱収縮によって被接合部材（上部材または下部材）が反る、あるいはうねる（凹凸が生じる）という問題が生じる可能性がある。このため、冷却工程で徐々に冷却を行うことが望ましい。例えば、一般には１００℃まで６０秒以内で冷却するが、反りを低減させようとすると１００℃まで約４００秒かけておこなう場合がある。 At this time, when the solder joint member is formed of a material that melts completely like ordinary solder, there is a problem that the member to be joined (upper member or lower member) warps or undulates (unevenness occurs) due to thermal contraction. may occur. Therefore, it is desirable to cool gradually in the cooling process. For example, although it is generally cooled to 100° C. within 60 seconds, it may take about 400 seconds to cool to 100° C. in order to reduce warpage.

本開示では、金属粒子１１の主成分がＳｎよりも熱膨張係数の低いＮｉであるため、はんだシート１０の熱収縮量が小さく、また、被接合部材（第１対象物２および第２対象物３）の各々の熱膨張係数が３×１０－６／Ｋ以上１３×１０－６／Ｋ未満であり、第１対象物２および第２対象物３の間の熱膨張係数差は５×１０－６／Ｋ未満であるため、反りは小さく、接合部材１に生じる残留応力も低くすることができる。このため、特に、冷却工程の時間を長くする必要がない。In the present disclosure, since the main component of the metal particles 11 is Ni, which has a lower coefficient of thermal expansion than Sn, the amount of thermal shrinkage of the solder sheet 10 is small, and the members to be joined (the first object 2 and the second object 3) each has a thermal expansion coefficient of 3×10 −6 /K or more and less than 13×10 −6 /K, and the thermal expansion coefficient difference between the first object 2 and the second object 3 is 5×10 Since it is less than -6 /K, the warp is small and the residual stress generated in the joint member 1 can be reduced. Therefore, it is not particularly necessary to lengthen the time of the cooling process.

実際のパワーモジュールへの適用においては、例えば、半導体素子および回路パターンが形成された回路基板と、放熱板とが、上記の接合部材１を介して接合され得る。接合部材１（はんだシート１０）は、接合面積サイズに依らず、パワーモジュールのダイボンド部、ベース付け部等への適用が可能である。 In actual application to a power module, for example, a circuit board on which a semiconductor element and a circuit pattern are formed and a heat sink can be joined via the joining member 1 . The joining member 1 (solder sheet 10) can be applied to a die-bonding part, a base attaching part, etc. of a power module regardless of the joining area size.

なお、はんだシート１０中の酸素濃度も重要である。金属粒子１１が酸化されやすいＮｉを含み、金属粒子１１の表面積は大きい。このため、わずかな金属粒子１１の表面酸化が生じた場合でも、金属粒子１１の界面から酸化が進んでいくと、全体としての酸化量は大きくなり、濡れ性に大きく影響する。そのため、はんだシート１０中の酸素濃度が高いと、真空デシケータ内等で保管しておかないと良好な接合部材が形成されない。したがって、良好な接合部材を形成するためには、はんだシート１０中の酸素濃度は、０より多く５００ｐｐｍ未満であることが好ましい。 The oxygen concentration in solder sheet 10 is also important. The metal particles 11 contain Ni, which is easily oxidized, and the surface area of the metal particles 11 is large. Therefore, even if the surface of the metal particles 11 is slightly oxidized, as the oxidation progresses from the interface of the metal particles 11, the amount of oxidation as a whole increases, which greatly affects the wettability. Therefore, when the oxygen concentration in the solder sheet 10 is high, a good joint member cannot be formed unless the solder sheet 10 is stored in a vacuum desiccator or the like. Therefore, in order to form a good joint member, the oxygen concentration in solder sheet 10 is preferably more than 0 and less than 500 ppm.

以下に実施例を挙げて本開示をさらに詳細に説明するが、本開示はこれら実施例に限定されるものではない。 EXAMPLES The present disclosure will be described in more detail with examples below, but the present disclosure is not limited to these examples.

（試験例１）
図１を参照して説明した上記実施の形態の通りの手順で、第１対象物２および第２対象物３の各々の熱膨張係数を表１に示されるように変化させて、接合サンプル（サンプル１～７）を作製した。なお、はんだシート１０に添加される金属粒子１１の粒径（平均粒径：Ｄ５０）は１０μｍである。(Test example 1)
The thermal expansion coefficients of each of the first object 2 and the second object 3 were changed as shown in Table 1 in the same manner as in the above embodiment described with reference to FIG. Samples 1 to 7) were prepared. The particle size (average particle size: D50) of the metal particles 11 added to the solder sheet 10 is 10 μm.

第１対象物２としては、ＣｕＭｏ合金板（厚み：１ｍｍ、サイズ：２０ｍｍ×２０ｍｍ）を使用した。ＣｕＭｏ合金板の最表面は銅無垢であり、該最表面にめっき処理は施されていない。このＣｕＭｏ合金板では、ＣｕとＭｏの配合比率を変えて、表１に示されるように熱膨張係数を変化させた。ただし、熱膨張係数が２の第１対象物としては、インバー合金を使用した。 A CuMo alloy plate (thickness: 1 mm, size: 20 mm×20 mm) was used as the first object 2 . The outermost surface of the CuMo alloy plate is pure copper, and is not plated. In this CuMo alloy plate, the compounding ratio of Cu and Mo was changed to change the thermal expansion coefficient as shown in Table 1. However, as the first object with a thermal expansion coefficient of 2, an Invar alloy was used.

なお、ＤＢＣ（Direct Bonded Copper）基板またはＣＩＣ（銅・インバー・銅）基板では、それらの基板を構成する三層の厚さにより、熱膨張係数を任意に調整することができる。 In the case of a DBC (Direct Bonded Copper) substrate or a CIC (copper-invar-copper) substrate, the thermal expansion coefficient can be arbitrarily adjusted by adjusting the thickness of the three layers that constitute the substrate.

第２対象物３の厚みは１００μｍ、サイズは１０ｍｍ×１０ｍｍである。この第２対象物３の熱膨張係数は、第１対象物２と同様にＣｕＭｏ合金およびインバー合金の配合比率によって、表１に示されるように変化させた。 The second object 3 has a thickness of 100 μm and a size of 10 mm×10 mm. The coefficient of thermal expansion of this second object 3 was changed as shown in Table 1 by the compounding ratio of the CuMo alloy and the Invar alloy as in the case of the first object 2 .

被接合部材の種類によって濡れ性が異なることがないようにするため、第１対象物２および第２対象物３の各々の接合側の表面には、厚み３μｍのＮｉめっきが施された。 In order to prevent the wettability from varying with the type of member to be joined, the surface of each of the first object 2 and the second object 3 on the joining side was plated with Ni to a thickness of 3 μm.

上記のようにして得られた表１に示される組み合わせの接合サンプルについて、パワーサイクル試験を模擬した高速熱衝撃試験をおこなった。具体的には、１０秒間の通電ＯＮ（到達温度：１７５℃）と１０秒間の通電ＯＦＦ（到達温度：５０℃）とからなる１サイクルを１０万サイクル繰り返す熱衝撃試験を実施した。 A high-speed thermal shock test simulating a power cycle test was performed on the bonded samples of the combinations shown in Table 1 obtained as described above. Specifically, a thermal shock test was performed by repeating 100,000 cycles of energization ON for 10 seconds (reaching temperature: 175° C.) and energization OFF for 10 seconds (reaching temperature: 50° C.).

熱衝撃試験後に、接合サンプルの接合部材の層の厚み方向の断面を作成し、該断面についての透過Ｘ線画像を２値化して画像解析を行うことにより、該断面における接合部材全体の面積（１００％）に対する接合部材に生じた空隙の面積比率を測定した。そして、空隙の面積比率が１０％以上である場合を「ＮＧ」と評価し、１０％未満であれば実用上問題ないため「ＯＫ」と評価した。評価結果を表１に示す。 After the thermal shock test, a cross-section in the thickness direction of the layer of the bonding member of the bonding sample is created, and the transmission X-ray image of the cross-section is binarized and image analysis is performed to obtain the area of the entire bonding member in the cross section ( 100%) were measured. When the area ratio of voids was 10% or more, it was evaluated as "NG", and when it was less than 10%, there was no practical problem, so it was evaluated as "OK". Table 1 shows the evaluation results.

Figure 0007267522000001
Figure 0007267522000001

表１に示される結果から、第１対象物２および第２対象物３の熱膨張係数が３×１０－６／Ｋ（３．０×１０－６／Ｋ）以上１３×１０－６／Ｋ（１３．０×１０－６／Ｋ）未満であり、第１対象物２と第２対象物３との間の熱膨張係数の差が５×１０－６／Ｋ（５．０×１０－６／Ｋ）未満である場合は、評価結果がＯＫであり、高速熱衝撃試験後に接合部材に空隙が発生しにくいことが分かる。したがって、本開示によれば、高温動作する半導体装置においてパワーサイクルに対する接合信頼性の高い接合部材、および、それを用いた半導体装置を提供できることが分かる。From the results shown in Table 1, the thermal expansion coefficients of the first object 2 and the second object 3 are 3×10 −6 /K (3.0×10 −6 /K) or more and 13×10 −6 /K (13.0×10 −6 /K), and the difference in thermal expansion coefficient between the first object 2 and the second object 3 is 5×10 −6 /K (5.0×10 − 6 /K), the evaluation result is OK, and it can be seen that voids are less likely to occur in the bonded member after the high-speed thermal shock test. Therefore, according to the present disclosure, it is possible to provide a bonding member with high bonding reliability against power cycles in a semiconductor device that operates at high temperatures, and a semiconductor device using the same.

なお、この結果には、接合部（接合部材と被接合部材）の熱膨張係数も関係している。上述の通り、被接合部材（第１対象物２および第２対象物３）で拘束された接合部材には、横方向の引張圧縮応力が加わり、縦方向の割れが生じる。すなわち、接合部材１の熱膨張係数が小さければ発生する応力も小さくすることができる。本開示では、Ｎｉを主成分として含む金属粒子１１を使用している。該金属粒子１１を使用した接合部材１の熱膨張係数が接合信頼性にどの程度影響するかを、公知文献から予想するのは困難である。 It should be noted that this result is also related to the thermal expansion coefficient of the joint (member to be joined and member to be joined). As described above, the joining members restrained by the members to be joined (the first object 2 and the second object 3) are subjected to lateral tensile and compressive stress, and cracks occur in the longitudinal direction. That is, if the thermal expansion coefficient of the joining member 1 is small, the generated stress can be reduced. In the present disclosure, metal particles 11 containing Ni as a main component are used. It is difficult to predict from known literature how much the thermal expansion coefficient of the joining member 1 using the metal particles 11 affects the joining reliability.

本発明者らが実際に接合部材１の熱膨張係数等を検討した結果、接合部材の熱膨張係数が１６×１０－６／Ｋ以上２０×１０－６／Ｋ未満であり、かつ、接合部材の断面（接合部材の層の厚み方向の断面）において、接合部材の全体の面積（１００％）に対して、上記低融点相（Ｓｎを主成分として含み３００℃未満の融点を有する相）の面積の比率が２％以上２０％未満である場合（すなわち、接合部材１の総量に対する低融点相１２の量の比率が２体積％以上２０体積％未満である場合）に、良好な結果（表１のサンプル２～４）が得られることが分かった。The inventors of the present invention actually examined the thermal expansion coefficient and the like of the bonding member 1, and found that the thermal expansion coefficient of the bonding member is 16 × 10 -6 /K or more and less than 20 × 10 -6 /K, and the bonding member (cross section in the thickness direction of the layer of the bonding member), the low melting point phase (a phase containing Sn as a main component and having a melting point of less than 300 ° C.) with respect to the entire area (100%) of the bonding member Good results (Table It was found that samples 2-4) of 1 were obtained.

今回開示された実施の形態および実施例はすべての点で例示であって制限的なものではないと考えられるべきである。本開示の範囲は上記した説明ではなくて請求の範囲によって示され、請求の範囲と均等の意味および範囲内でのすべての変更が含まれることが意図される。 It should be considered that the embodiments and examples disclosed this time are illustrative in all respects and not restrictive. The scope of the present disclosure is indicated by the scope of claims rather than the above description, and is intended to include all changes within the meaning and scope of equivalence to the scope of claims.

１ 接合部材、１０ はんだシート、１１ 金属粒子、１２ 低融点相、１３ 金属間化合物、２ 第１対象物（放熱板）、３ 第２対象物（回路基板）、４ 加熱炉、５ ホットプレート、６ 冷却プレート。 1 joining member 10 solder sheet 11 metal particles 12 low melting point phase 13 intermetallic compound 2 first object (radiator plate) 3 second object (circuit board) 4 heating furnace 5 hot plate 6 cooling plate.

Claims (5)

第１対象物と第２対象物とを接合する、接合部材であって、
Ｎｉを主成分として含む金属粒子と、
Ｓｎを主成分として含み３００℃未満の融点を有する低融点相と、
Ｓｎと前記金属粒子との間の相互拡散により生じた３００℃以上の融点を有する金属間化合物と、
を含み、
前記接合部材の総量に対する前記低融点相の量の比率は２体積％以上２０体積％未満であり、前記低融点相は更にＣｕを含み、
前記第１対象物および前記第２対象物の熱膨張係数は３×１０－６／Ｋ以上１３×１０－６／Ｋ未満であり、前記第１対象物と前記第２対象物との間の熱膨張係数の差は５×１０－６／Ｋ未満であり、
前記接合部材の熱膨張係数は１６×１０－６／Ｋ以上２０×１０－６／Ｋ未満である、接合部材。 A joining member that joins a first object and a second object,
Metal particles containing Ni as a main component;
a low melting point phase containing Sn as a main component and having a melting point of less than 300°C;
an intermetallic compound having a melting point of 300° C. or higher generated by interdiffusion between Sn and the metal particles;
including
The ratio of the amount of the low melting point phase to the total amount of the bonding member is 2% by volume or more and less than 20% by volume, and the low melting point phase further contains Cu,
The coefficient of thermal expansion of the first object and the second object is 3×10 −6 /K or more and less than 13×10 −6 /K, and the thermal expansion coefficient between the first object and the second object is the difference in thermal expansion coefficients is less than 5×10 −6 /K;
A bonding member, wherein the thermal expansion coefficient of the bonding member is 16×10 −6 /K or more and less than 20×10 −6 /K. 前記低融点相は、さらにＡｇを含む、請求項１に記載の接合部材。 The joining member according to claim 1, wherein the low melting point phase further contains Ag. 前記金属粒子は、さらに、Ｆｅ、Ｃｒ、Ｃ、ＣｕおよびＳｉからなる群から選択される少なくとも１種の成分を含む、請求項１に記載の接合部材。 2. The joining member according to claim 1, wherein said metal particles further contain at least one component selected from the group consisting of Fe, Cr, C, Cu and Si. 前記第１対象物が、放熱板であり、
前記第２対象物が、半導体素子および配線回路を有する回路基板である、請求項１～３のいずれか１項に記載の接合部材。 the first object is a radiator plate,
The joining member according to any one of claims 1 to 3, wherein the second object is a circuit board having a semiconductor element and a wiring circuit. 放熱板と、半導体素子および配線回路を有する回路基板と、を備え、
前記放熱板と前記回路基板とが、請求項４に記載の接合部材を介して接合されている、半導体装置。 A heat sink and a circuit board having a semiconductor element and a wiring circuit,
5. A semiconductor device, wherein the heat sink and the circuit board are bonded together via the bonding member according to claim 4.
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