JP2015155108A

JP2015155108A - Metal conjugate, waveguide for antenna, and semiconductor device

Info

Publication number: JP2015155108A
Application number: JP2014031430A
Authority: JP
Inventors: 浩次山▲崎▼; Koji Yamazaki
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2014-02-21
Filing date: 2014-02-21
Publication date: 2015-08-27

Abstract

PROBLEM TO BE SOLVED: To provide at low cost, a metal conjugate having no deformation of the edge portion of a joint or no flowing out of a joining material of the joint to the outside, few in deformation of an aluminum-based member, and joined by a favorable joint with few voids.

SOLUTION: A metal conjugate is produced by contacting both tin-plated films of a plurality of aluminum-based members, and pressurizing and heating to bring to formation of an Al-Ag-Sn phase on a joint. The aluminum-based member is prepared by forming a silver-plating film 2 having a thickness of 0.3-1.5 μm on the surface of the aluminum-based member 1 comprising aluminum as a main component and further forming on the silver-plating film, a tin-plating film 3 having a thickness of 1/2 or less of the silver-plating film.

Description

本発明は、アルミニウム部材同士を接合させた金属接合体、アンテナ用導波路及び半導体装置に関する。 The present invention relates to a metal bonded body in which aluminum members are bonded to each other, an antenna waveguide, and a semiconductor device.

伝熱性や熱放散性に優れるが軽量化の点で課題のある銅（Ｃｕ）に替わって、軽量化に優れ、伝熱性や熱放散性が銅に次いで優れ、かつ銅よりも安価なアルミニウム（Ａｌ）が、近年、電子機器、通信機器、航空機、自動車等の熱交換器、ヒートパイプ、ヒートシンクあるいはアンテナ用導波管等に幅広く用いられている。 Aluminum (excellent in heat transfer and heat dissipation but replacing copper (Cu), which is problematic in terms of weight reduction, is superior in weight reduction, heat transfer and heat dissipation are next to copper, and cheaper than copper ( In recent years, Al) has been widely used in electronic devices, communication devices, aircraft, automobile heat exchangers, heat pipes, heat sinks, antenna waveguides, and the like.

上記の中でアンテナ導波管について、現在、通信用途として３０〜３００ＧＨｚ帯のミリ波が注目を集めている。酸素の吸収帯が５５〜６５ＧＨｚ帯に存在するほか、水蒸気圧や降雨の影響を著しく受けるので、その周波数帯を用いた地上無線は大気による電波の減衰が多く、近距離通信に限定される。そこで、用途としては、例えば自動車の事故回避システムなどが上げられる。自動車では、事故を回避したり、あるいは、避けられないまでも被害を最小限に食い止めるプリクラッシュセーフティシステムが多くの車種で適用されており、今や、ハイブリッドやディーゼルなどのエコ技術と並んでクルマの売れ行きを左右するファクターとなっている。矢野経済研究所の調査（先進運転支援システム（ＡＤＡＳ）用キーデバイス／コンポーネント世界市場に関する調査結果２０１２、２０１２年１１月１４日発表）によると、２０２０年の自動車用レーダー市場について、７６/７７ＧＨｚ帯のミリ波レーダーでは２０１２年の３８２億円から１６９１億円へ、検知距離の短い２４ＧＨｚ帯準ミリ波レーダーも含めると２７４２億円に達するとの見通しを発表している。また、自動車用途以外にも、６０ＧＨｚの周波数を用いて無線通信に用いようとしている。 Among the above-mentioned antenna waveguides, millimeter waves in the 30 to 300 GHz band are currently attracting attention as communication applications. Since the oxygen absorption band exists in the 55 to 65 GHz band and is significantly affected by water vapor pressure and rainfall, terrestrial radio using the frequency band is often attenuated by the atmosphere and is limited to short-range communication. Therefore, as an application, for example, an automobile accident avoidance system is raised. In automobiles, pre-crash safety systems that avoid accidents or minimize damage if unavoidable have been applied to many vehicle types, and now, along with eco technologies such as hybrid and diesel, It is a factor that affects sales. According to a survey by Yano Research Institute (Survey results on key device / component global market for advanced driver assistance systems (ADAS) 2012, announced on November 14, 2012), the 76/77 GHz band for the automotive radar market in 2020 As for the millimeter-wave radar of 2012, it is announced that it will reach 274.2 billion yen from 38.2 billion yen in 2012 to 169.1 billion yen, including the 24GHz band quasi-millimeter wave radar with a short detection distance. Moreover, it is going to use for radio | wireless communication using the frequency of 60 GHz besides the use for a motor vehicle.

また、ミリ波は、空港等で導入が進むとされている衣服の下を透視する全身スキャナー等に用いられようとしているなど、今後、大きな成長が見込まれる。更に、長野県にある国立天文台野辺山宇宙電波観測所では宇宙からやってくるミリ波の観測が行われており、星の誕生やブラックホールの研究において世界的な成果があがっている。 Millimeter waves are also expected to grow significantly in the future, as they are about to be used in full-body scanners that see through under clothes that are supposed to be introduced at airports. Furthermore, the National Astronomical Observatory Nobeyama Space Radio Observatory in Nagano Prefecture observes millimeter waves coming from outer space, and has achieved worldwide results in the birth of stars and research on black holes.

このミリ波レーダーを受ける側としてミリ波用アンテナが必要である。アンテナ内導波路は、複雑な線路になっているため、ドリルなどで一度に導波路を開けるのは困難である。そのため、通常は導波路が形成された板を何層か積層させて、導波路を形成する。この導波路が形成された板の材質は、通常、ＳＵＳやＣｕが使用されていた。しかし、ＳＵＳは比重が７．７〜８．０ｇ／ｃｍ^３であり、Ｃｕは比重がＣｕ：８．９６ｇ／ｃｍ^３であるため、何枚も積層すると筐体が重くなってしまう。これに対してＡｌは比重が２．７０ｇ／ｃｍ^３であり、軽量であり、取り扱いが容易である。しかし、ＡｌはＳＵＳやＣｕに比べて酸化しやすく、接合するのは比較的困難な材料である。また、ＳＵＳの融点は１４００〜１５００℃であり、また、Ｃｕの融点は１０８５℃であるのに対して、Ａｌは６６０℃と融点が低く且つ軟らかいため、加熱あるいは加圧して接合しようとすると、容易に変形して、導波路が曲がったり、あるいは接合部のエッジ部分が変形して導波路内にはみ出してしまうといった問題が起こる。そのため、Ａｌでは設計通りの経路が形成されず、導波路内でミリ波の減衰が多くなってしまう。 A millimeter wave antenna is required on the side receiving the millimeter wave radar. Since the waveguide inside the antenna is a complicated line, it is difficult to open the waveguide at once with a drill or the like. Therefore, a waveguide is usually formed by laminating several layers on which a waveguide is formed. Usually, SUS or Cu is used as the material of the plate on which the waveguide is formed. However, since SUS has a specific gravity of 7.7 to 8.0 g / cm ³ and Cu has a specific gravity of Cu: 8.96 g / cm ³ , the case becomes heavy when many sheets are stacked. In contrast, Al has a specific gravity of 2.70 g / cm ³ , is lightweight, and is easy to handle. However, Al is easier to oxidize than SUS and Cu and is a relatively difficult material to join. In addition, SUS has a melting point of 1400 to 1500 ° C., and Cu has a melting point of 1085 ° C., whereas Al has a low melting point of 660 ° C. and is soft. There is a problem that the waveguide is easily deformed and the waveguide is bent or the edge portion of the joint is deformed and protrudes into the waveguide. For this reason, Al does not form the designed path, and millimeter wave attenuation increases in the waveguide.

このようなＡｌの接合方法として、例えば、特許文献１では、Ａｌ系金属からなる両材料の間にＡｌと共晶反応を生じる元素として少なくともＺｎを含むインサート材を介在させ、両材料を相対的に加圧した状態で、共晶反応を生じる温度に加熱して両材料の接合界面に母材中のＡｌとの共晶反応による溶融物を生成させ、溶融物と共にＡｌの酸化皮膜を接合界面から排出して両材料を接合することを特徴とする接合方法が開示されている。また、特許文献２では、Ａｌ系材料からなる２つの被接合部材を相互に接合する方法として、被接合部材の接合面にＡｇ被覆層を形成し、Ａｇ被覆層上に平均粒子径５０ｎｍ以下のＡｇ粒子を配設し、両被接合部材を相互に押圧しながら、２８０℃以上でＡｌ系部材の固相線温度以下の温度に加熱する接合方法が開示されている。特許文献２には、押圧を２ＭＰａ以上の圧力で行うことが記載されている。特許文献２には、Ａｇ被覆層を無電解めっき又は電解めっき処理により形成することも記載されている。また、特許文献３では、アルミニウム合金を拡散接合するに際し、窒素雰囲気中で加熱、加圧するアルミニウム合金の拡散接合法が開示されている。特許文献３には、接合に際し、２重量％以上マグネシウムを含む合金をインサート材として用いるか、２重量％以上マグネシウムを含むアルミニウム合金を用いることが記載されている。また、特許文献３では、酸素残存量が７０ｐｐｍ以下の雰囲気で、加熱、加圧しており、加熱温度は、アルミニウム合金の固相線温度から４５℃低い温度から固相線温度の間であり、加圧力は、３ＭＰａ以上５ＭＰａであることも記載されている。 As such an Al joining method, for example, in Patent Document 1, an insert material containing at least Zn as an element that causes a eutectic reaction with Al is interposed between both materials made of an Al-based metal, and the two materials are relative to each other. In a state where pressure is applied to the material, it is heated to a temperature at which a eutectic reaction occurs to generate a melt by eutectic reaction with Al in the base material at the joint interface of both materials, and an Al oxide film is bonded to the joint interface together with the melt. A joining method is disclosed in which both materials are joined by being discharged from the container. Moreover, in patent document 2, as a method of mutually joining two to-be-joined members which consist of Al type material, an Ag coating layer is formed in the joining surface of a to-be-joined member, and an average particle diameter is 50 nm or less on Ag coating layer. A bonding method is disclosed in which Ag particles are disposed and heated to a temperature not lower than 280 ° C. and not higher than the solidus temperature of the Al-based member while pressing both members to be bonded to each other. Patent Document 2 describes that the pressing is performed at a pressure of 2 MPa or more. Patent Document 2 also describes that the Ag coating layer is formed by electroless plating or electrolytic plating. Patent Document 3 discloses a diffusion bonding method of an aluminum alloy that is heated and pressurized in a nitrogen atmosphere when the aluminum alloy is diffusion bonded. Patent Document 3 describes that an alloy containing 2 wt% or more magnesium is used as an insert material or an aluminum alloy containing 2 wt% or more magnesium is used for joining. Moreover, in patent document 3, it heats and pressurizes in the atmosphere whose oxygen residual amount is 70 ppm or less, The heating temperature is between the solidus temperature from 45 degrees C lower than the solidus temperature of the aluminum alloy, It is also described that the applied pressure is 3 MPa or more and 5 MPa.

国際公開第２０１２／０２９７８９号International Publication No. 2012/029789 特開２００７−３１９８９６号公報Japanese Patent Laid-Open No. 2007-31989 特開２０１０−０９４６８３号公報JP 2010-094683 A

上述の通り、Ａｌ系部材同士の接合時に、導波路が曲がったり、接合部のエッジ部分が変形したり、あるいは接合材が導波路内にはみ出してはいけない。特許文献１では、ＡｌとＺｎとの共晶反応によって、比較的低温で接合することはできるが、接合時に圧を加えて、Ａｌとの共晶反応による溶融物を生成させて、外部へ排出しているため、導波路内にその溶融物が進入してしまうため、ミリ波が減衰してしまう。また、特許文献２では、接合部に平均粒子径５０ｎｍ以下のＡｇ粒子を配置し、加圧によって接合しているが、ナノ粒子自体の製造方法が非常に複雑で、高コストであり、量産には不向きである。また、ナノ粒子同士とはいえ、拡散反応によって、バルク体と比べれば隙間は少なからず生じてしまい、良好な接合部を形成するのは困難である。さらに、このナノサイズのＡｇ粒子は相互に凝集して粗大化することを防止するために、粒子表面に有機物からなるコーティング膜が形成されている。この有機物は接合時の熱によって分解するが、その分解したガスは完全に抜ききらず、一部は有機残渣として部材に付着する。例えば、導波路付近を接合した場合、その残渣が導波路に付着しているため、例えＡｌ系部材が変形していなくても、残渣付着箇所が突起のような形状となり、ミリ波を減衰させてしまう可能性がある。また、このナノサイズのＡｇ粒子は塗布時にはペースト状であり、このような材料を塗布して加圧すると、はんだのように外部に少なからず流れ出し、導波路にも流れ出してしまい、その箇所が導波路において突起のような形状となってしまうため、ミリ波が減衰してしまう。従って、実用上、ナノ粒子を使用するのは困難であるといえる。これまで、本発明者は、上述のようなＡｇ粒子を適用すべく、様々な粒子径のＡｇ粒子や様々な有機溶剤を用いたペーストで接合を試みたが、流れ出し量を制御するのは困難であり、また内部に有機残渣が必ず残ってしまった。また、流れ出し量を抑制しようと圧を下げると、接合部に空隙が多くなり、良好な接合が得られなかった。 As described above, at the time of joining the Al-based members, the waveguide should not be bent, the edge portion of the joined portion may be deformed, or the joining material should not protrude into the waveguide. In Patent Document 1, bonding can be performed at a relatively low temperature by a eutectic reaction between Al and Zn, but pressure is applied during bonding to generate a melt by the eutectic reaction with Al, and then discharge to the outside. Therefore, the melt enters the waveguide, so that the millimeter wave is attenuated. Further, in Patent Document 2, Ag particles having an average particle diameter of 50 nm or less are arranged at the joining portion and joined by pressurization. However, the manufacturing method of the nanoparticles themselves is very complicated, high cost, and mass production. Is unsuitable. Moreover, although it is nanoparticle, it is difficult to form a favorable junction part by a diffusion reaction, compared with a bulk body, and a space | gap will arise not a little. Further, in order to prevent the nano-sized Ag particles from being aggregated and coarsened, a coating film made of an organic substance is formed on the particle surface. The organic matter is decomposed by heat at the time of joining, but the decomposed gas is not completely removed, and a part of the organic matter adheres to the member as an organic residue. For example, when the vicinity of the waveguide is joined, the residue adheres to the waveguide, so even if the Al-based member is not deformed, the residue adhesion portion has a shape like a protrusion, which attenuates millimeter waves. There is a possibility that. In addition, the nano-sized Ag particles are pasty at the time of application, and when such a material is applied and pressed, it flows out to the outside as much as solder and also flows into the waveguide, and the portion is guided. Since the waveguide is shaped like a protrusion, the millimeter wave is attenuated. Therefore, it can be said that it is difficult to use nanoparticles in practical use. Until now, in order to apply the above Ag particles, the present inventor tried joining with pastes using Ag particles of various particle sizes and various organic solvents, but it is difficult to control the flow-out amount. In addition, an organic residue always remained inside. Further, when the pressure was lowered in order to suppress the flow-out amount, voids increased in the joint portion, and good joint could not be obtained.

次に、特許文献３では、接合界面にマグネシウムを含むアルミニウム合金を挿入しているが、アルミニウム表面の酸化速度よりもマグネシウムによる還元作用の方が早いため、Ａｌ表面の酸化膜が除去され加圧、加熱によって接合可能だが、接合温度はアルミニウム合金の固相線温度から３０〜４５℃低い５６２℃の場合、変形率（接合前後のブロックと板材の重ね合わせた高さ差／接合前の高さ）は約１５％としている。特許文献３では、ロウ材による接合方法と比較すればアルミニウム合金の変形は少ないとしているが、１５％は変形してしまうため、導波路を形成するには不適である。 Next, in Patent Document 3, an aluminum alloy containing magnesium is inserted at the bonding interface, but since the reduction action by magnesium is faster than the oxidation rate of the aluminum surface, the oxide film on the Al surface is removed and pressurized. Can be joined by heating, but when the joining temperature is 562 ° C., which is 30 to 45 ° C. lower than the solidus temperature of the aluminum alloy, the deformation rate (height difference between the block and plate before and after joining / height before joining) ) Is about 15%. In Patent Document 3, it is said that the deformation of the aluminum alloy is small as compared with the joining method using the brazing material, but 15% is deformed, which is not suitable for forming the waveguide.

従って、本発明は、上記のような問題を解決するためになされたものであり、接合部のエッジ部分が変形したり、あるいは接合部の接合材が外部に流れ出すことがなく、アルミニウム系部材の変形が少なく、ボイドの少ない良好な接合部で接合された金属接合体を低コストで提供することを目的とする。 Therefore, the present invention has been made to solve the above-described problems, and the edge portion of the joint portion is not deformed, or the joining material of the joint portion does not flow out to the outside, and the aluminum-based member An object of the present invention is to provide a metal joined body joined at a good joint with little deformation and few voids at low cost.

本発明は、アルミニウムを主成分とするアルミニウム系部材の表面に厚さ０．３μｍ〜１．５μｍの銀めっき皮膜が形成され、該銀めっき皮膜上に該銀めっき皮膜の１／２以下の厚さの錫めっき皮膜が形成された複数のアルミニウム系部材の該錫めっき皮膜同士を接触させ、加圧・加熱することによって接合部にＡｌ−Ａｇ−Ｓｎ相を形成させたことを特徴とする金属接合体である。 In the present invention, a silver plating film having a thickness of 0.3 μm to 1.5 μm is formed on the surface of an aluminum-based member containing aluminum as a main component, and the thickness of the silver plating film is ½ or less of the silver plating film. A metal characterized in that an Al-Ag-Sn phase is formed at a joint by bringing the tin-plated films of a plurality of aluminum-based members formed with the same thickness into contact with each other and pressurizing and heating. It is a joined body.

本発明によれば、接合部のエッジ部分が変形したり、あるいは接合部の接合材が外部に流れ出すことがなく、アルミニウム系部材の変形が少なく、ボイドの少ない良好な接合部で接合された金属接合体を低コストで提供することができる。 According to the present invention, the edge portion of the joint portion is not deformed, or the joining material of the joint portion does not flow to the outside, and the metal is joined at a good joint portion with less deformation of the aluminum-based member and less voids. A joined body can be provided at low cost.

実施の形態１の金属接合体の製造工程を説明するための概略図である。FIG. 5 is a schematic diagram for explaining a manufacturing process for the metal joined body according to the first embodiment. 実施の形態１で製造した金属接合体の接合部の状態と、比較のために製造した金属接合体の接合部の状態を説明するための模式断面図である。It is a schematic cross section for demonstrating the state of the junction part of the metal bonded body manufactured in Embodiment 1, and the state of the bonded part of the metal bonded body manufactured for comparison. 実施の形態２の半導体装置の製造工程を説明するための概略図である。FIG. 10 is a schematic diagram for illustrating a manufacturing process for the semiconductor device of the second embodiment. 実施例１で得られた金属接合体の接合部の断面観察結果（ａ）及び比較例１で得られた金属接合体の接合部の断面観察結果（ｂ）である。It is the cross-sectional observation result (a) of the junction part of the metal joining body obtained in Example 1, and the cross-sectional observation result (b) of the joining part of the metal joining body obtained in Comparative Example 1.

実施の形態１．
本発明を実施するための実施の形態１について説明する。本発明に係る金属接合体の製造工程の概略図を図１に示す。アルミニウムを主成分とするアルミニウム系部材として、例えば長さ１０ｍｍ×幅１０ｍｍ×厚さ２ｍｍのアルミニウム板１を用意する。このアルミニウム板１は、アルミニウムを主成分とするものであればよく、例えばＡ１０５０のような純アルミニウムからなるものであってもよい。次に、アルミニウム板１の表面に厚さ０．３μｍ〜１．５μｍの範囲の銀めっき皮膜２を形成する。銀めっき皮膜２の好ましい厚さは０．５μｍ〜１．２μｍである。次に、銀めっき皮膜２上に錫めっき皮膜３を銀めっき皮膜２の１／２以下の厚さで形成する。錫めっき皮膜３の好ましい厚さは、銀めっき皮膜２の厚さの３／１０以上４／１０以下である。銀めっき皮膜２及び錫めっき皮膜３の形成方法は、特に限定されるものではないが、電解めっき法、無電解めっき法等の公知の方法を採用することができる。この銀めっき皮膜２及び錫めっき皮膜３が形成されたアルミニウム板１を２枚用意し、アルミニウム板１の錫めっき皮膜３同士を接触させ、簡易ジグによって０．１ＭＰａ〜１０ＭＰａ、好ましくは０．１ＭＰａ〜１ＭＰａの圧４を加える。このような簡易ジグは、市販されているものをそのまま用いてもよいし、あるいはカスタマイズしたものを用いてもよく、例えば、岸田エンジニアリング、アユミ工業株式会社等から入手することができる。次に、簡易ジグで圧を加えた状態のアルミニウム板１を、還元雰囲気下（錫の酸化膜を除去できる雰囲気であればよく、例えば、ギ酸還元雰囲気）で加熱が可能なバッチ炉に投入し、錫の融点（約２３０℃）よりも高い温度、好ましくは２５０℃〜２８０℃で好ましくは５分間〜２０分間加熱保持し、その後、温度を下げ、金属接合体を得ることができる。加熱温度及び加熱時間を上記範囲内とすることにより、接合部のエッジ部分の変形や、アルミニウム板１そのものの変形をより少なくすることができる。このような還元雰囲気下で加熱が可能なバッチ炉は、市販されているものをそのまま用いてもよいし、あるいはカスタマイズしたものを用いてもよく、例えば、アユミ工業株式会社等から入手することができる。こうして得られる本発明の金属接合体の接合部にはボイドが極めて少なく、良好な接合部となる。 Embodiment 1 FIG.
Embodiment 1 for carrying out the present invention will be described. FIG. 1 shows a schematic diagram of a manufacturing process of a metal joined body according to the present invention. As an aluminum-based member mainly composed of aluminum, for example, an aluminum plate 1 having a length of 10 mm, a width of 10 mm, and a thickness of 2 mm is prepared. The aluminum plate 1 may be made of aluminum as a main component, and may be made of pure aluminum such as A1050. Next, a silver plating film 2 having a thickness in the range of 0.3 μm to 1.5 μm is formed on the surface of the aluminum plate 1. The preferable thickness of the silver plating film 2 is 0.5 μm to 1.2 μm. Next, a tin plating film 3 is formed on the silver plating film 2 with a thickness of ½ or less of the silver plating film 2. A preferable thickness of the tin plating film 3 is 3/10 or more and 4/10 or less of the thickness of the silver plating film 2. Although the formation method of the silver plating film 2 and the tin plating film 3 is not specifically limited, Well-known methods, such as an electroplating method and an electroless-plating method, are employable. Two aluminum plates 1 on which the silver plating film 2 and the tin plating film 3 are formed are prepared, the tin plating films 3 of the aluminum plate 1 are brought into contact with each other, and 0.1 MPa to 10 MPa, preferably 0.1 MPa by a simple jig. Apply a pressure 4 of ~ 1 MPa. As such a simple jig, a commercially available one may be used as it is or a customized one may be used, and for example, it can be obtained from Kishida Engineering, Ayumi Industry Co., Ltd. or the like. Next, the aluminum plate 1 in a state in which pressure is applied with a simple jig is put into a batch furnace that can be heated in a reducing atmosphere (any atmosphere capable of removing a tin oxide film, for example, a formic acid reducing atmosphere). The temperature is higher than the melting point of tin (about 230 ° C.), preferably 250 ° C. to 280 ° C., preferably 5 to 20 minutes, and then the temperature is lowered to obtain a metal joined body. By setting the heating temperature and the heating time within the above ranges, the deformation of the edge portion of the joint and the deformation of the aluminum plate 1 itself can be reduced. The batch furnace that can be heated in such a reducing atmosphere may be a commercially available one, or may be a customized one, for example, obtained from Ayumi Industry Co., Ltd. it can. The joint part of the metal joined body of the present invention thus obtained has very few voids and is a good joint part.

比較のため、アルミニウム板１に銀めっき皮膜２及び錫めっき皮膜３を形成する前にアルミニウムあるいは銀に対して拡散抑制効果のあるニッケル皮膜を形成してから、ニッケル皮膜上に銀めっき皮膜２及び錫めっき皮膜３を本発明と同様の厚み範囲で形成した後、本発明と同様の条件でアルミニウム板１を接合して金属接合体を製造すると、金属接合体の接合部には微小なボイドが散見される。 For comparison, before forming the silver plating film 2 and the tin plating film 3 on the aluminum plate 1, a nickel film having a diffusion suppressing effect on aluminum or silver is formed, and then the silver plating film 2 and the nickel film are formed on the nickel film. After the tin plating film 3 is formed in the same thickness range as in the present invention, the aluminum plate 1 is bonded under the same conditions as in the present invention to produce a metal bonded body. It is often seen.

アルミニウム板１と銀めっき皮膜２との界面に、アルミニウムあるいは銀に対して拡散抑制効果の高いニッケルの有無によって、接合部のボイド量に差が見られることから、以下に説明するような現象が起きていると考えられる。即ち、本発明では、図１に示すように、表面に銀めっき皮膜２及び錫めっき皮膜３が形成されたアルミニウム板１を加熱・加圧すると、アルミニウムと銀との間で拡散反応が進み、Ａｌ−Ａｇ拡散相５が形成されると共に、銀と錫との界面にもＡｇ−Ｓｎ拡散相６が形成される。Ａｌ−Ａｇ拡散相５とは、例えば、少なくともＡｇ_２Ａｌ（ａｔ％）及びＡｇ_３Ａｌ（ａｔ％）を含む相のことを言う。Ａｇ−Ｓｎ拡散相６とは、例えば、少なくともＡｇ_３Ｓｎ（ａｔ％）及びＡｇ_４Ｓｎ（ａｔ％）を含む相のことを言う。その後、加熱・加圧状態を保持することによって反応が進み、Ａｌ−Ａｇ拡散相５及びＡｇ−Ｓｎ拡散相６が合わさり、内部で均一に拡散し、Ａｌ−Ａｇ−Ｓｎ相７が形成されるものと考えられる。Ａｌ−Ａｇ―Ｓｎ相７とは、例えば、少なくともＡｇ_２〜５（Ａｌ，Ｓｎ）を含む相のことを言う。このような拡散反応は、Ａｌ−Ａｇ−Ｓｎの３元系反応であり、図２（ａ）に示すように、それぞれの元素が結晶を粗大化するのを抑制するように働き、Ａｌ−Ａｇ−Ｓｎ相７が凹凸にならずに比較的平坦になると考えられる。これは、Ｃｕ−Ｓｎ反応において、例えばＮｉを添加すると、Ｃｕ−Ｎｉ−Ｓｎという３元系反応となり、結晶成長が微細化されて凹凸形状の形成が抑制されることが良く知られており、この反応と同様のメカニズムによるものと考えられる。 Since there is a difference in the amount of voids in the joint portion depending on the presence or absence of nickel having a high diffusion suppressing effect on aluminum or silver at the interface between the aluminum plate 1 and the silver plating film 2, the phenomenon described below occurs. It is thought that it is awake. That is, in the present invention, as shown in FIG. 1, when the aluminum plate 1 having the silver plating film 2 and the tin plating film 3 formed on the surface is heated and pressurized, a diffusion reaction proceeds between aluminum and silver, The Al—Ag diffusion phase 5 is formed, and the Ag—Sn diffusion phase 6 is also formed at the interface between silver and tin. The Al—Ag diffusion phase 5 refers to a phase containing at least Ag ₂ Al (at%) and Ag ₃ Al (at%), for example. The Ag—Sn diffusion phase 6 refers to a phase containing at least Ag ₃ Sn (at%) and Ag ₄ Sn (at%), for example. Thereafter, the reaction proceeds by maintaining the heated / pressurized state, the Al-Ag diffusion phase 5 and the Ag-Sn diffusion phase 6 are combined and uniformly diffused inside, and the Al-Ag-Sn phase 7 is formed. It is considered a thing. The Al—Ag—Sn phase 7 refers to a phase containing at least Ag _2-5 (Al, Sn), for example. Such a diffusion reaction is an Al—Ag—Sn ternary reaction, and as shown in FIG. 2A, each element acts to suppress coarsening of the crystal, and Al—Ag It is considered that the Sn phase 7 becomes relatively flat without being uneven. It is well known that, for example, when Ni is added in the Cu—Sn reaction, it becomes a ternary reaction of Cu—Ni—Sn, the crystal growth is refined, and the formation of uneven shapes is suppressed, This is probably due to the same mechanism as this reaction.

一方、アルミニウムあるいは銀に対して拡散抑制効果の高いニッケルめっき皮膜１５をアルミニウム板１と銀めっき皮膜２との間に挿入すると、アルミニウムと銀との反応が無くなるため、主に銀と錫との拡散反応のみとなる。このような拡散反応は、Ａｇ−Ｓｎの２元系反応であり、図２（ｂ）に示すように、Ａｇ−Ｓｎ拡散相６は凹凸形状が形成されると考えられる。これは、Ａｇ−Ｓｎでなくとも、Ｃｕ−Ｓｎ及びＮｉ−Ｓｎでも同様の傾向があり、Ｓｎとの２元系反応においては、一つ一つの結晶成長が粗大化してしまい、その結晶成長を抑制するような添加元素がなく、かつそれぞれの結晶成長が多少ばらつきを持ち、拡散の起点となるポイントから等方的に成長するため、凹凸形状が形成され易いと考えられる。このような凹凸形状を重ね合わせると、凸部は先に重なるが、凹部は重ならず、やがて、残りのＳｎ相８がＡｇ−Ｓｎ拡散相６に変わるときの体積収縮によって、凹部に微小なボイドが形成されてしまうと考えられる。 On the other hand, when the nickel plating film 15 having a high diffusion suppressing effect on aluminum or silver is inserted between the aluminum plate 1 and the silver plating film 2, the reaction between aluminum and silver is eliminated. Only diffusion reaction. Such a diffusion reaction is a binary reaction of Ag—Sn, and the Ag—Sn diffusion phase 6 is considered to have an uneven shape as shown in FIG. This is not the case with Ag-Sn, but Cu-Sn and Ni-Sn have the same tendency. In the binary reaction with Sn, each crystal growth becomes coarse, Since there is no additive element to suppress and each crystal growth has some variation and isotropic growth from the starting point of diffusion, it is considered that the uneven shape is likely to be formed. When such concavo-convex shapes are overlapped, the convex portion overlaps first, but the concave portion does not overlap. Eventually, due to the volume shrinkage when the remaining Sn phase 8 changes to the Ag—Sn diffusion phase 6, the concave portion becomes minute. It is thought that voids are formed.

また、本発明において、錫めっき皮膜３の厚さを銀めっき皮膜２の１／２以下の厚さに設定したのは、以下の計算結果に基づいている。銀と錫との拡散反応では、Ａｇ_３Ｓｎが主に形成されることが良く知られており、Ａｇ_３Ｓｎは、ａｔ％で３：１であるので、Ａｇ：７５ａｔ％及びＳｎ：２５ａｔ％となる。このａｔ％を、Ａｇの原子量を１０８ｇ／ｍｏｌ、Ｓｎの原子量を１１９ｇ／ｍｏｌとしてｗｔ％に換算すると、Ａｇ：７３ｗｔ％及びＳｎ：２７ｗｔ％となる。更に、このｗｔ％を、Ａｇの密度を１０．５ｇ／ｃｍ^３、Ｓｎの密度を７．４ｇ／ｃｍ^３としてｖｏｌ％に換算すると、Ａｇ：６６ｖｏｌ％及びＳｎ：３４ｖｏｌ％となる。即ち、銀の周りに錫が無限にあっても、Ａｇ_３Ｓｎになるのは、銀の体積の約半分（３４／６６＝０．５２≒０．５）で、残りの錫は反応せずに、残存し、接合部の外部に流れ出すと考えられるためである。 In addition, in the present invention, the thickness of the tin plating film 3 is set to 1/2 or less the thickness of the silver plating film 2 based on the following calculation result. It is well known that Ag ₃ Sn is mainly formed in the diffusion reaction between silver and tin. Since Ag ₃ Sn is 3: 1 at%, Ag: 75 at% and Sn: 25 at% It becomes. When this at% is converted into wt% with the atomic weight of Ag being 108 g / mol and the atomic weight of Sn being 119 g / mol, Ag: 73 wt% and Sn: 27 wt% are obtained. Further, when this wt% is converted to vol% with the Ag density being 10.5 g / cm ³ and the Sn density being 7.4 g / cm ³ , Ag: 66 vol% and Sn: 34 vol% are obtained. That is, even if there is an infinite number of tin around silver, Ag ₃ Sn becomes about half of the volume of silver (34/66 = 0.52≈0.5), and the remaining tin does not react. This is because it is thought that the residual material flows out of the joint.

なお、本実施の形態では、銀めっき皮膜２の材質は、純銀であることが好ましいが、銀を主成分とするものであればよく、本発明の効果を阻害しない限り、例えば、Ｃｕ、Ｚｎ、Ｓｂ、Ｉｎ、Ｎｉ、Ｇｅ、Ｐ、Ａｌ、Ｇａ、Ｂｉ、Ｔｉ、Ａｕ、Ｓｉ、Ｃ等が微量添加されていてもよい。また、本発明において、錫めっき皮膜３の材質は、純錫であることが好ましいが、錫を主成分とするものであればよく、本発明の効果を阻害しない限り、例えば、Ａｇ、Ｃｕ、Ｚｎ、Ｓｂ、Ｉｎ、Ｎｉ、Ｇｅ、Ｐ、Ａｌ、Ｇａ、Ｂｉ、Ｔｉ、Ａｕ、Ｓｉ、Ｃ等が微量添加されていてもよい。なお、銀、錫及びアルミニウム以外の上記した別の添加元素が微量添加されていると、加熱時にそれらの添加元素も界面の反応に加わることになり、多元系反応となるため、反応相の凹凸はより低減する方向に働くと考えられる。 In the present embodiment, the material of the silver plating film 2 is preferably pure silver, but may be any material as long as it contains silver as a main component. Sb, In, Ni, Ge, P, Al, Ga, Bi, Ti, Au, Si, C, or the like may be added in a small amount. Further, in the present invention, the material of the tin plating film 3 is preferably pure tin, but may be one containing tin as a main component. For example, Ag, Cu, A small amount of Zn, Sb, In, Ni, Ge, P, Al, Ga, Bi, Ti, Au, Si, C, or the like may be added. If a small amount of the above-mentioned additional elements other than silver, tin and aluminum is added, these additional elements will also participate in the interface reaction during heating, resulting in a multi-component reaction. Is considered to work in the direction of further reduction.

本発明の金属接合体は、接合部のエッジ部分が変形したり、あるいは接合部の接合材が外部に流れ出すことがなく、アルミニウム系部材の変形が少なく、ボイドの少ない良好な接合部で接合されているので、ミリ波アンテナ用導波路に有用である。アンテナ用導波路に用いる場合、本発明の金属接合体の接合部が、導波路の側壁の少なくとも一部を構成するようにすればよい。また、ミリ波用途でなくても、サブミリ波（３００ＧＨｚ〜）、マイクロ波（３〜３０ＧＨｚ）、超短波（３０ＭＨｚ〜０．３ＧＨｚ）、短波（３〜３０ＭＨｚ）、中波（３００ｋＨｚ〜３ＭＨｚ）、長波（３０〜３００ｋＨｚ）、超長波（３〜３０ｋＨｚ）、極超長波（３〜３ｋＨｚ）のあらゆる導波路に使用可能である。 In the metal joined body of the present invention, the edge portion of the joined portion is not deformed, or the joining material of the joined portion does not flow to the outside, the aluminum-based member is less deformed, and is joined with a good joined portion with less voids. Therefore, it is useful for a waveguide for a millimeter wave antenna. When used for an antenna waveguide, the joint of the metal joined body of the present invention may constitute at least a part of the side wall of the waveguide. Even if it is not used for millimeter waves, sub-millimeter waves (300 GHz to), microwaves (3 to 30 GHz), ultrashort waves (30 MHz to 0.3 GHz), short waves (3 to 30 MHz), medium waves (300 kHz to 3 MHz), long waves (30 to 300 kHz), ultralong waves (3 to 30 kHz), and ultralong waves (3 to 3 kHz) can be used for all waveguides.

実施の形態２．
まず、近年のパワー半導体を用いた半導体装置関連では、Ｓｉよりも高温下で動作可能なＳｉＣやＧａＮが使用され始めており、半導体素子の耐熱性が高くなることで、接合部にも耐熱性や厳しい環境下での高い信頼性が求められている。具体的な使用温度は、Ｓｉの場合、１２５℃あるいは一部使用用途を限定すれば１５０℃までは実用上問題はないが、ＳｉＣの場合、単体では４００℃まで動作可能であるため、少なくともＳｉよりも高温の１７５℃あるいは２００℃で、ＳｉＣ半導体素子を用いたパワー半導体装置は使用される。このような高い耐熱性を有する接合材として、Ｐｂを主成分とする高Ｐｂ含有はんだやＡｕを主成分とするＡｕ系はんだが候補として挙げられるが、Ｐｂは有毒性の観点で問題があり、Ａｕ系はんだは高価であるという問題がある。この他に、特許文献２に記載されるような反応性の高いナノ粒子あるいはマイクロ粒子を有機剤で被覆し、適当な溶剤でペースト化した金属粒子ペーストも候補に挙がるが、ペーストの製造工程が複雑なため高コストである、また、印刷ばらつきも生じ易く、接合後に、有機残渣が部材に付着して汚染してしまうという問題もある。また、加熱・加圧によって形成された金属の接合部がよりバルクに近くて緻密であれば、応力緩和性が低く、ＳｉＣの高温動作による高歪み域では、熱歪みによって容易にクラックが発生する。一方、低圧低温接合で緻密性を落とすと、粒子同士の反応が進まず、高い応力緩和性によってクラックの進展は抑制できても、パワー半導体に必要な放熱性を確保することはできない。
実施の形態１で説明した通り、本発明の金属接合体では、Ａｌ−Ａｇ拡散相５及びＡｇ−Ｓｎ拡散相６が合わさり、Ａｌ−Ａｇ−Ｓｎ相７になることで、結晶粒が微細化し、反応相の凹凸を抑制し、錫の凝固収縮によるボイドを抑制することができ、更に、反応相の結晶粒が微細化することで、熱歪みに対する応力耐性も高くなることが期待できる。そこで、実施の形態２では、実施の形態１で説明した金属接合体を半導体装置（特にパワー半導体装置）の接合部に適用する場合について説明する。 Embodiment 2. FIG.
First, in recent semiconductor devices using power semiconductors, SiC and GaN that can operate at higher temperatures than Si have begun to be used. High reliability in harsh environments is required. The specific use temperature is 125 ° C. in the case of Si, or practically up to 150 ° C. if limited in part, but in the case of SiC, since it can operate up to 400 ° C. alone, at least Si Power semiconductor devices using SiC semiconductor elements are used at higher temperatures of 175 ° C. or 200 ° C. As a bonding material having such a high heat resistance, a high Pb-containing solder containing Pb as a main component and an Au-based solder containing Au as a main component can be cited as candidates, but Pb has a problem in terms of toxicity, There is a problem that Au-based solder is expensive. In addition to this, metal particle pastes that are coated with highly reactive nanoparticles or microparticles as described in Patent Document 2 with an organic agent and pasted with an appropriate solvent are also candidates. Since it is complicated, it is expensive, and printing variations are likely to occur, and there is a problem that organic residues adhere to the member and become contaminated after joining. Also, if the metal joint formed by heating and pressing is closer to the bulk and denser, the stress relaxation property is low, and cracks are easily generated due to thermal strain in a high strain region due to high-temperature operation of SiC. . On the other hand, if the denseness is lowered by low-pressure and low-temperature bonding, the reaction between particles does not proceed, and even though the progress of cracks can be suppressed by high stress relaxation, the heat dissipation necessary for the power semiconductor cannot be ensured.
As described in the first embodiment, in the metal joined body of the present invention, the Al—Ag diffusion phase 5 and the Ag—Sn diffusion phase 6 are combined to form an Al—Ag—Sn phase 7, whereby the crystal grains are refined. It can be expected that the unevenness of the reaction phase can be suppressed, voids due to solidification shrinkage of tin can be suppressed, and further, the stress resistance against thermal strain can be increased by making the crystal grains of the reaction phase finer. Therefore, in the second embodiment, a case where the metal bonded body described in the first embodiment is applied to a bonded portion of a semiconductor device (particularly, a power semiconductor device) will be described.

本発明の実施の形態２に係る半導体装置の製造工程の概略図を図４に示す。まず、上下面にアルミニウムを主成分とするアルミニウム系上電極９及び下電極１０が形成されている絶縁基板１１を用意する。このような絶縁基板１１としては、半導体装置に用いられている公知のものを用いることができ、例えば、ＤＯＷＡパワーデバイス社製のものが挙げられる。なお、ＤＯＷＡパワーデバイス社が２０１３年に発表した文献（ＭＥＳ２０１３：銀ナノペーストとＡｌＮ基板との接合信頼性評価）によれば、アルミニウムを主成分とするアルミニウム系上電極９及び下電極１０と窒化アルミニウム（ＡｌＮ）基板とは溶湯接合法により直接接合されている。次に、上電極９及び下電極１０表面の接合部となる部分にのみ、厚さ０．３μｍ〜１．５μｍの範囲の銀めっき皮膜２を形成する。次に、銀めっき皮膜２上に錫めっき皮膜３を銀めっき皮膜２の１／２以下の厚さで形成する。
アルミニウムを主成分とするアルミニウム系放熱板１２を用意する。このアルミニウム系放熱板１２は、アルミニウムを主成分とするものであればよく、例えばＡ１０５０のような純アルミニウムからなるものであってもよい。次に、アルミニウム系放熱板１２表面の接合部となる部分にのみ、厚さ０．３μｍ〜１．５μｍの範囲の銀めっき皮膜２を形成する。次に、銀めっき皮膜２上に錫めっき皮膜３を銀めっき皮膜２の１／２以下の厚さで形成する。
表面にアルミニウムを主成分とするアルミニウム系メタライズ１３が形成された半導体素子１４を用意する。この半導体素子１４は、Ｓｉ、ＳｉＣ、ＧａＮ等であることができる。次に、アルミニウム系メタライズ１３の表面に厚さ０．３μｍ〜１．５μｍの範囲の銀めっき皮膜２を形成する。次に、銀めっき皮膜２上に錫めっき皮膜３を銀めっき皮膜２の１／２以下の厚さで形成する。
次に、半導体素子１４の錫めっき皮膜３と、絶縁基板１１の錫めっき皮膜３とを接触させると共に、絶縁基板１１の錫めっき皮膜３と、アルミニウム系放熱板１２の錫めっき皮膜３とを接触させ、０．１ＭＰａ〜１０ＭＰａ、好ましくは０．１ＭＰａ〜１ＭＰａの圧４を加える。圧を加えた状態のものを、還元雰囲気下（錫の酸化膜を除去できる雰囲気であればよく、例えば、ギ酸還元雰囲気）で加熱が可能なバッチ炉に投入し、錫の融点（約２３０℃）よりも高い温度に保持し、その後、温度を下げ、半導体装置を得ることができる。こうして得られる本発明の半導体装置では、接合部にボイドが極めて少なく、また、熱歪みに対する応力耐性が高いという利点を有する。 FIG. 4 shows a schematic diagram of the manufacturing process of the semiconductor device according to the second embodiment of the present invention. First, an insulating substrate 11 having an upper aluminum electrode 9 and a lower electrode 10 mainly composed of aluminum on the upper and lower surfaces is prepared. As such an insulating substrate 11, a well-known substrate used in a semiconductor device can be used, for example, a substrate manufactured by DOWA Power Device Corporation. According to a document published in 2013 by DOWA Power Devices (MES2013: Evaluation of bonding reliability between silver nanopaste and AlN substrate), aluminum-based upper electrode 9 and lower electrode 10 mainly composed of aluminum and nitrided The aluminum (AlN) substrate is directly bonded by a molten metal bonding method. Next, the silver plating film 2 having a thickness in the range of 0.3 μm to 1.5 μm is formed only on the portion that becomes the joint between the upper electrode 9 and the lower electrode 10. Next, a tin plating film 3 is formed on the silver plating film 2 with a thickness of ½ or less of the silver plating film 2.
An aluminum-based heat radiating plate 12 mainly composed of aluminum is prepared. The aluminum-based heat radiating plate 12 may be made of aluminum as a main component, and may be made of pure aluminum such as A1050. Next, the silver plating film 2 having a thickness in the range of 0.3 μm to 1.5 μm is formed only on the portion that becomes the bonding portion on the surface of the aluminum heat sink 12. Next, a tin plating film 3 is formed on the silver plating film 2 with a thickness of ½ or less of the silver plating film 2.
A semiconductor element 14 having an aluminum metallized layer 13 mainly composed of aluminum on the surface is prepared. The semiconductor element 14 can be Si, SiC, GaN, or the like. Next, a silver plating film 2 having a thickness in the range of 0.3 μm to 1.5 μm is formed on the surface of the aluminum metallization 13. Next, a tin plating film 3 is formed on the silver plating film 2 with a thickness of ½ or less of the silver plating film 2.
Next, the tin plating film 3 of the semiconductor element 14 and the tin plating film 3 of the insulating substrate 11 are brought into contact with each other, and the tin plating film 3 of the insulating substrate 11 and the tin plating film 3 of the aluminum-based heat radiation plate 12 are brought into contact with each other. And a pressure 4 of 0.1 MPa to 10 MPa, preferably 0.1 MPa to 1 MPa is applied. The pressure is applied to a batch furnace that can be heated in a reducing atmosphere (any atmosphere capable of removing a tin oxide film, such as a formic acid reducing atmosphere), and the melting point of tin (about 230 ° C. ), And then the temperature is lowered to obtain a semiconductor device. The semiconductor device of the present invention thus obtained has the advantages that the joint has very few voids and has high stress resistance against thermal strain.

なお、本実施の形態では、銀めっき皮膜２の好ましい厚さ、錫めっき皮膜３の好ましい厚さ並びに銀めっき皮膜２及び錫めっき皮膜３の形成方法は、実施の形態１で説明した通りであるので、ここでは説明を省略する。また、半導体素子１４と絶縁基板１１とアルミニウム系放熱板１２との接合を同時に行ったが、これらの接合は別々に行ってもよい。 In the present embodiment, the preferred thickness of the silver plating film 2, the preferred thickness of the tin plating film 3, and the method for forming the silver plating film 2 and the tin plating film 3 are as described in the first embodiment. Therefore, explanation is omitted here. Moreover, although the semiconductor element 14, the insulating substrate 11, and the aluminum-type heat sink 12 were joined at the same time, these joining may be performed separately.

以下、実施例及び比較例により本発明の詳細を説明するが、これらによって本発明が限定されるものではない。
＜実施例１＞
アルミニウムを主成分とするアルミニウム系部材として、長さ１０ｍｍ×幅１０ｍｍ×厚さ２ｍｍのアルミニウム板（Ａ１０５０）を用意した。アルミニウム板の表面に厚さ１μｍの銀めっき皮膜を形成した。次に、銀めっき皮膜上に厚さ０．５μｍの錫めっき皮膜を形成した。この銀めっき皮膜及び錫めっき皮膜が形成されたアルミニウム板を２枚用意し、アルミニウム板の錫めっき皮膜同士を接触させ、簡易ジグによって０．５ＭＰａの圧を加えた。ギ酸還元雰囲気下で加熱が可能なバッチ炉に投入し、錫の融点（約２３０℃）よりも２０℃高い２５０℃で５分間加熱保持し、その後、温度を下げ、実施例１の金属接合体サンプルを得た。 Hereinafter, although an Example and a comparative example demonstrate the detail of this invention, this invention is not limited by these.
<Example 1>
An aluminum plate (A1050) having a length of 10 mm, a width of 10 mm, and a thickness of 2 mm was prepared as an aluminum-based member mainly composed of aluminum. A silver plating film having a thickness of 1 μm was formed on the surface of the aluminum plate. Next, a tin plating film having a thickness of 0.5 μm was formed on the silver plating film. Two aluminum plates on which the silver plating film and the tin plating film were formed were prepared, the tin plating films of the aluminum plate were brought into contact with each other, and a pressure of 0.5 MPa was applied by a simple jig. The metal joined body of Example 1 was put into a batch furnace capable of heating in a formic acid reducing atmosphere, and heated and held at 250 ° C., which is 20 ° C. higher than the melting point of tin (about 230 ° C.) for 5 minutes. A sample was obtained.

実施例１の金属接合体サンプルの接合部の断面観察結果を図４（ａ）に示す。図４（ａ）より、接合部にはボイドがなく、良好な接合部が得られたことが分かる。また、実施例１の金属接合体サンプルの全体の空隙量を評価するため、超音波探傷装置（ＳＡＴ（Scanning Acoustic Tomograph）、日立エンジニアリング・アンド・サービス製Fine SATIII））による観察を行った。得られたＳＡＴ画像をパーソナルコンピューター（ＰＣ）の解析ソフト（Adobe Photoshop Elements 11）にて２値化を行い、得られた２値化画像からボイド率を算出した。なお、ボイド率は誤差±０．５％であり、小数点以下第１位を四捨五入して算出した。また、断面観察により、接合部から溶融した錫を主成分とする相の流れ出しの有無を確認したところ、流れ出しは５μｍ未満であった。これらの結果より、実施例１の金属接合体サンプルでは、接合部の接合材が外部に殆ど流れ出ず、また、ボイド率が０％であり、非常に良好な接合部が得られていることが確認された。 The cross-sectional observation result of the junction part of the metal conjugate | zygote sample of Example 1 is shown to Fig.4 (a). From FIG. 4A, it can be seen that there was no void in the joint, and a good joint was obtained. Further, in order to evaluate the total void amount of the metal joined body sample of Example 1, observation was performed using an ultrasonic flaw detector (SAT (Scanning Acoustic Tomograph), Fine SAT III manufactured by Hitachi Engineering & Service)). The obtained SAT image was binarized with analysis software (Adobe Photoshop Elements 11) of a personal computer (PC), and the void ratio was calculated from the obtained binarized image. The void ratio had an error of ± 0.5%, and was calculated by rounding off the first decimal place. Moreover, when the cross-sectional observation confirmed the presence or absence of the flow of the phase which has the main component of the tin fuse | melted from the junction part, the flow-out was less than 5 micrometers. From these results, in the metal bonded body sample of Example 1, the bonding material of the bonded portion hardly flows out to the outside, and the void ratio is 0%, so that a very good bonded portion is obtained. confirmed.

＜比較例１＞
アルミニウムを主成分とするアルミニウム系部材として、長さ１０ｍｍ×幅１０ｍｍ×厚さ２ｍｍのアルミニウム板（Ａ１０５０）を用意した。アルミニウム板の表面に厚さ１μｍのニッケル皮膜を形成してから、ニッケル皮膜上に銀めっき皮膜及び錫めっき皮膜を実施例１と同様の厚みで形成した後、実施例１と同様の条件でアルミニウム板を接合し、比較例１の金属接合体サンプルを得た。 <Comparative Example 1>
An aluminum plate (A1050) having a length of 10 mm, a width of 10 mm, and a thickness of 2 mm was prepared as an aluminum-based member mainly composed of aluminum. After a nickel film having a thickness of 1 μm is formed on the surface of the aluminum plate, a silver plating film and a tin plating film are formed on the nickel film with the same thickness as in Example 1, and then aluminum is formed under the same conditions as in Example 1. The plates were joined to obtain a metal joined body sample of Comparative Example 1.

比較例１の金属接合体サンプルの接合部の断面観察結果を図４（ｂ）に示す。図４（ｂ）より、接合部には微小なボイドが散見され、実施例１の金属接合体サンプルと比較しても明確な差が見られた。また、実施例１と同様にして金属接合体サンプルの全体の空隙量を評価したところ、比較例１の金属接合体サンプルでは、ボイド率が約２０％であり、断面観察結果と相関が得られた。また、断面観察により、接合部から溶融した錫を主成分とする相の流れ出しの有無を確認したところ、流れ出しは５μｍ未満であった。 FIG. 4B shows a cross-sectional observation result of the joint portion of the metal joined body sample of Comparative Example 1. From FIG.4 (b), the micro void was scattered in the junction part, and even if compared with the metal joined body sample of Example 1, the clear difference was seen. Further, when the total void amount of the metal joined body sample was evaluated in the same manner as in Example 1, the metal joined body sample of Comparative Example 1 had a void ratio of about 20%, and a correlation with the cross-sectional observation result was obtained. It was. Moreover, when the cross-sectional observation confirmed the presence or absence of the flow of the phase which has the main component of the tin fuse | melted from the junction part, the flow-out was less than 5 micrometers.

＜実施例２〜６及び比較例２〜６＞
次に、表１に示すように銀めっき皮膜及び錫めっき皮膜の厚さを変えて、実施例１と同様に金属接合体サンプルを各１０個（ｎ＝１０）作製した。得られた金属接合体サンプルについて、実施例１と同様にＳＡＴ画像の２値化画像からボイド率を算出した。１０個（ｎ＝１０）のサンプルのうち最も大きいボイド値をその金属接合体サンプルのボイド率とした。また、断面観察により、接合部から溶融した錫を主成分とする相の流れ出しの有無を確認し、接合部から５μｍ以上の流れ出しが確認された場合は「×」とし、５μｍ未満である場合は「○」とした。なお、通常の強力な還元能力を有するフッ素系フラックスを用いてＳｎ系はんだを接合したときのボイド率が１０％程度であるので、金属接合体サンプルのボイド率が１０％以下であれば合格と判断でき、１０％よりも高ければ不合格と判断できる。 <Examples 2-6 and Comparative Examples 2-6>
Next, as shown in Table 1, ten metal joint samples (n = 10) were prepared in the same manner as in Example 1 by changing the thicknesses of the silver plating film and the tin plating film. For the obtained metal joined body sample, the void ratio was calculated from the binarized image of the SAT image in the same manner as in Example 1. The largest void value among the 10 samples (n = 10) was defined as the void ratio of the metal joined body sample. In addition, by cross-sectional observation, it was confirmed whether or not a phase mainly composed of molten tin was flown out from the bonded portion. If flow out of 5 μm or more was confirmed from the bonded portion, it was determined as “x”. “○”. In addition, since the void rate when joining Sn type solder using the fluorine-type flux which has normal strong reduction capability is about 10%, if the void rate of a metal joined body sample is 10% or less, it will pass. If it is higher than 10%, it can be determined as a failure.

表１の結果から分かるように、銀めっき皮膜の厚さが０．３μｍ〜１．５μｍの範囲で、且つ錫めっき皮膜の厚さが銀めっき皮膜の１／２以下であれば、ボイド率が小さく、且つ外部への流れ出しもなく良好な結果であった。 As can be seen from the results in Table 1, if the thickness of the silver plating film is in the range of 0.3 μm to 1.5 μm and the thickness of the tin plating film is 1/2 or less of the silver plating film, the void ratio is The result was small and the flow out to the outside was good.

銀めっき皮膜の厚さが０．３μｍ未満である比較例２では、ボイド率は４０％と急激に悪化する傾向が確認された。これは、加熱時に酸化し易い母材のアルミニウムが、銀めっき皮膜及び錫めっき皮膜内を拡散したり、銀めっき皮膜あるいは錫めっき皮膜の粒界から表面に現れてしまい、その結果、ギ酸還元雰囲気中ではアルミニウムの酸化膜を還元することができず、強固なアルミニウムの酸化膜が表面に一部介在してしまったため、極端に錫の濡れ性が低下し、ボイドが発生したと考えられる。また、銀めっき皮膜が１．５μｍ超である比較例３では、アルミニウムがＡｇ−Ｓｎ拡散相に十分に拡散せず、実質的にはＡｇ−Ｓｎという２元系反応となってしまい、反応相が凹凸形状となり、凹部での錫の凝固収縮によって微小なボイドが多数発生してしまい、ボイド率が１０％以上となったと考えられる。 In Comparative Example 2 in which the thickness of the silver plating film was less than 0.3 μm, it was confirmed that the void ratio tended to deteriorate rapidly with 40%. This is because the base aluminum, which is easily oxidized during heating, diffuses in the silver plating film and tin plating film, or appears on the surface from the grain boundary of the silver plating film or tin plating film, resulting in a formic acid reducing atmosphere. In this case, the aluminum oxide film could not be reduced, and a strong aluminum oxide film was partially interposed on the surface. Therefore, it was considered that the wettability of tin was extremely lowered and voids were generated. Further, in Comparative Example 3 in which the silver plating film exceeds 1.5 μm, aluminum does not sufficiently diffuse into the Ag—Sn diffusion phase, resulting in a substantially binary reaction of Ag—Sn. It is considered that a large number of fine voids were generated due to solidification shrinkage of tin in the concave portions, and the void ratio became 10% or more.

錫めっき皮膜の厚さが銀めっき皮膜の１／２超である比較例４〜６では、いずれも外部への流れ出しが生じてしまい、良好な接合が得られなかった。 In Comparative Examples 4 to 6 in which the thickness of the tin plating film was more than ½ of the silver plating film, all flowed out to the outside, and good bonding was not obtained.

なお、上記実施例及び比較例における銀めっき皮膜の厚さ及び錫めっき皮膜の厚さは、予め算出しためっき成膜速度とめっき処理時間とから計算した値である。 In addition, the thickness of the silver plating film and the thickness of the tin plating film in the above examples and comparative examples are values calculated from the plating film formation rate and the plating treatment time calculated in advance.

＜実施例７＞
厚さ０．６３５ｍｍの窒化アルミニウム板の上下面に厚さ０．４ｍｍのアルミニウムｌ上電極及び厚さ０．４ｍｍのアルミニウム下電極が形成されている絶縁基板（長さ４５ｍｍ×幅４５ｍｍ、ＤＯＷＡパワーデバイス社製）。この上電極及び下電極両方の接合部となる部分にのみ、厚さ１μｍの銀めっき皮膜を形成した。次に、両方の銀めっき皮膜上に厚さ０．５μｍの錫めっき皮膜を形成した。
次に、アルミニウム（Ａ１０５０）放熱板（長さ５０ｍｍ×幅６０ｍｍ×厚さ３ｍｍ）を用意し、放熱板の接合部となる部分にのみ、厚さ１μｍの銀めっき皮膜を形成した。次に、銀めっき皮膜上に厚さ０．５μｍの錫めっき皮膜を形成した。
次に、ＳｉＣ半導体素子（長さ８ｍｍ×幅８ｍｍ×厚さ０．３ｍｍ）を用意し、表面に厚さ３μｍのアルミニウムメタライズを形成し、アルミニウムメタライズ上に厚さ１μｍの銀めっき皮膜を形成した。次に、銀めっき皮膜上に厚さ０．５μｍの錫めっき皮膜を形成した。
このように調製した絶縁基板と放熱板とを、絶縁基板とＳｉＣ半導体素子とを、それぞれ順に０．５ＭＰａの圧を加えた状態でギ酸還元雰囲気下にて錫の融点（約２３０℃）よりも２０℃高い２５０℃で５分間加熱保持し、実施例７の半導体装置サンプルを得た。 <Example 7>
Insulating substrate (length 45 mm × width 45 mm, DOWA power, with 0.4 mm aluminum upper electrode and 0.4 mm aluminum lower electrode formed on the upper and lower surfaces of an aluminum nitride plate 0.635 mm thick Device). A silver plating film having a thickness of 1 μm was formed only on the portion that becomes the joint of both the upper electrode and the lower electrode. Next, a tin plating film having a thickness of 0.5 μm was formed on both silver plating films.
Next, an aluminum (A1050) heat radiating plate (length 50 mm × width 60 mm × thickness 3 mm) was prepared, and a silver plating film having a thickness of 1 μm was formed only on a portion to be a joint portion of the heat radiating plate. Next, a tin plating film having a thickness of 0.5 μm was formed on the silver plating film.
Next, an SiC semiconductor element (length 8 mm × width 8 mm × thickness 0.3 mm) was prepared, an aluminum metallization with a thickness of 3 μm was formed on the surface, and a silver plating film with a thickness of 1 μm was formed on the aluminum metallization. . Next, a tin plating film having a thickness of 0.5 μm was formed on the silver plating film.
The insulating substrate and the heat sink prepared in this manner, the insulating substrate and the SiC semiconductor element, respectively, in a state where a pressure of 0.5 MPa was sequentially applied to each other than the melting point of tin (about 230 ° C.) in a formic acid reducing atmosphere. The semiconductor device sample of Example 7 was obtained by heating and holding at 250 ° C., which is 20 ° C. higher for 5 minutes.

＜比較例７＞
アルミニウムと銀との間に厚さ１μｍのニッケルめっき皮膜を挿入したこと以外は実施例７と同様にして、比較例７の半導体装置サンプルを得た。 <Comparative Example 7>
A semiconductor device sample of Comparative Example 7 was obtained in the same manner as in Example 7 except that a nickel plating film having a thickness of 1 μm was inserted between aluminum and silver.

実施例７及び比較例７で得られた半導体装置サンプルの接合後及びヒートサイクル（低温−４０℃×３０分、高温＋２００℃×３０分）の６００サイクル後において、半導体素子と絶縁基板との接合部及び絶縁基板と放熱板との接合部のＳＡＴ観察を行い、得られたＳＡＴ像をＰＣのソフトウェア解析によって２値化し、ボイド率を算出した。ヒートサイクル前のボイド率を表２に示し、ヒートサイクル後のボイド率を表３に示す。なお、初期接合時のボイド率の合否判定は半導体素子と絶縁基板との接合部は５％、絶縁基板と放熱板との接合部は１０％とした。半導体素子と絶縁基板との間の方がボイド率の合否判定が厳しいのは、実動作では、半導体素子周辺部が発熱するため、発熱源により近い接合部では厳しい条件としている。実施例７と比較例７とでは、どちらの接合部も実施例７が優れており、基準を満たしていた。比較例７では、どちらの接合部も基準を満たすことができなかった。その後、ヒートサイクル後においては、表３に示すように実施例７ではどちらの接合部でも僅かに微増したが、十分基準を満たしていることが分かった。比較例７では、どちらも接合後から更に大きく増加する傾向が確認された。これは、接合時の微小なボイド伝いにクラックが進展してしまったためと推定される。一方、実施例７では、アルミニウムが拡散したことによって、Ａｌ−Ａｇ−Ｓｎ相の結晶粒径が微細化され、分散強化により、クラックの進展が抑制されたと推定される。 After bonding of the semiconductor device samples obtained in Example 7 and Comparative Example 7 and after 600 cycles of heat cycle (low temperature−40 ° C. × 30 minutes, high temperature + 200 ° C. × 30 minutes), bonding of the semiconductor element and the insulating substrate SAT observation of the joint portion between the insulating portion and the insulating substrate and the heat radiating plate was performed, and the obtained SAT image was binarized by PC software analysis, and the void ratio was calculated. Table 2 shows the void ratio before the heat cycle, and Table 3 shows the void ratio after the heat cycle. In addition, the pass / fail judgment of the void ratio at the time of initial bonding was set to 5% for the bonded portion between the semiconductor element and the insulating substrate, and to 10% for the bonded portion between the insulating substrate and the heat sink. The reason why the void ratio is more strictly determined between the semiconductor element and the insulating substrate is that in the actual operation, the peripheral part of the semiconductor element generates heat. In Example 7 and Comparative Example 7, Example 7 was superior in both joints, and the standard was satisfied. In Comparative Example 7, neither joint could meet the criteria. Thereafter, after the heat cycle, as shown in Table 3, in Example 7, although slightly increased in both joints, it was found that the standard was sufficiently satisfied. In the comparative example 7, the tendency for both to increase further after joining was confirmed. This is presumably because cracks have propagated along the minute voids during bonding. On the other hand, in Example 7, it is presumed that due to the diffusion of aluminum, the crystal grain size of the Al—Ag—Sn phase was refined and the development of cracks was suppressed by dispersion strengthening.

１アルミニウム板、２銀めっき皮膜、３錫めっき皮膜、４圧、５Ａｌ−Ａｇ拡散相、６Ａｇ−Ｓｎ拡散相、７Ａｌ−Ａｇ−Ｓｎ相、８Ｓｎ相、９上電極、１０下電極、１１絶縁基板、１２放熱板、１３メタライズ、１４半導体素子、１５ニッケルめっき皮膜。 1 aluminum plate, 2 silver plating film, 3 tin plating film, 4 pressure, 5 Al-Ag diffusion phase, 6 Ag-Sn diffusion phase, 7 Al-Ag-Sn phase, 8 Sn phase, 9 upper electrode, 10 lower electrode , 11 Insulating substrate, 12 Heat sink, 13 Metallization, 14 Semiconductor element, 15 Nickel plating film.

Claims

アルミニウムを主成分とするアルミニウム系部材の表面に厚さ０．３μｍ〜１．５μｍの銀めっき皮膜が形成され、該銀めっき皮膜上に該銀めっき皮膜の１／２以下の厚さの錫めっき皮膜が形成された複数のアルミニウム系部材の該錫めっき皮膜同士を接触させ、加圧・加熱することによって接合部にＡｌ−Ａｇ−Ｓｎ相を形成させたことを特徴とする金属接合体。 A silver plating film having a thickness of 0.3 μm to 1.5 μm is formed on the surface of an aluminum-based member containing aluminum as a main component, and tin plating having a thickness of 1/2 or less of the silver plating film is formed on the silver plating film A metal joined body characterized in that an Al-Ag-Sn phase is formed in a joint portion by bringing the tin plating films of a plurality of aluminum-based members on which a film is formed into contact with each other and pressurizing and heating.

請求項１に記載の金属接合体の接合部が、導波路の側壁の少なくとも一部を構成していることを特徴とするアンテナ用導波路。 The antenna waveguide according to claim 1, wherein the joint portion of the metal joined body according to claim 1 constitutes at least a part of a side wall of the waveguide.

半導体素子上に形成されたアルミニウムを主成分とするアルミニウム系メタライズの表面に厚さ０．３μｍ〜１．５μｍの銀めっき皮膜が形成され、該銀めっき皮膜上に該銀めっき皮膜の１／２以下の厚さの錫めっき皮膜が形成された半導体素子の該錫めっき皮膜と、絶縁基板上に形成されたアルミニウムを主成分とするアルミニウム系電極の表面に厚さ０．３μｍ〜１．５μｍの銀めっき皮膜が形成され、該銀めっき皮膜上に該銀めっき皮膜の１／２以下の厚さの錫めっき皮膜が形成された絶縁基板の該錫めっき皮膜とを接触させ、加圧・加熱することによって接合部にＡｌ−Ａｇ−Ｓｎ相を形成させたことを特徴とする半導体装置。 A silver plating film having a thickness of 0.3 μm to 1.5 μm is formed on the surface of an aluminum-based metallization mainly composed of aluminum formed on a semiconductor element, and 1/2 of the silver plating film is formed on the silver plating film. The tin plating film of a semiconductor element having a tin plating film of the following thickness formed on the surface of an aluminum-based electrode mainly composed of aluminum formed on an insulating substrate with a thickness of 0.3 μm to 1.5 μm A silver plating film is formed, and the tin plating film of the insulating substrate in which a tin plating film having a thickness of 1/2 or less of the silver plating film is formed on the silver plating film is brought into contact with pressure and heated. Thereby, an Al—Ag—Sn phase is formed in the junction.

絶縁基板上に形成されたアルミニウムを主成分とするアルミニウム系電極の表面に厚さ０．３μｍ〜１．５μｍの銀めっき皮膜が形成され、該銀めっき皮膜上に該銀めっき皮膜の１／２以下の厚さの錫めっき皮膜が形成された絶縁基板の該錫めっき皮膜と、アルミニウムを主成分とするアルミニウム系放熱板の表面に厚さ０．３μｍ〜１．５μｍの銀めっき皮膜が形成され、該銀めっき皮膜上に該銀めっき皮膜の１／２以下の厚さの錫めっき皮膜が形成されたアルミニウム系放熱板の該錫めっき皮膜とを接触させ、加圧・加熱することによって接合部にＡｌ−Ａｇ−Ｓｎ相を形成させたことを特徴とする半導体装置。 A silver plating film having a thickness of 0.3 μm to 1.5 μm is formed on the surface of an aluminum-based electrode mainly composed of aluminum formed on an insulating substrate, and ½ of the silver plating film is formed on the silver plating film. A silver plating film having a thickness of 0.3 μm to 1.5 μm is formed on the surface of the tin plating film of the insulating substrate on which the tin plating film having the following thickness is formed and an aluminum-based heat sink having aluminum as a main component. The aluminum-based heat radiating plate in which a tin plating film having a thickness of 1/2 or less of the silver plating film is formed on the silver plating film is brought into contact with the tin plating film, and pressed and heated to join the joint portion. A semiconductor device characterized in that an Al—Ag—Sn phase is formed.