JP2006281292A - Conductive filler and low-temperature solder material - Google Patents
Conductive filler and low-temperature solder material Download PDFInfo
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Abstract
Description
本発明は、電気・電子機器の接合材料に用いられる「導電性フィラー」に関するもので、特に鉛フリーのはんだ材料、導電性接着剤に関する。 The present invention relates to a “conductive filler” used as a bonding material for electric / electronic devices, and more particularly to a lead-free solder material and a conductive adhesive.
はんだは、一般的に金属材料の接合に用いられ、溶融温度域（固相線温度から液相線温度の範囲）が４５０℃以下の合金材料とされる。従来、リフロー熱処理で使用するはんだ材料としては、一般的に融点１８３℃のＳｎ―３７Ｐｂ共晶はんだが用いられ、また、高耐熱性が要求される電子部品の内部等で使用される高温はんだとしては、固相線２７０℃、液相線３０５℃からなるＳｎ―９０Ｐｂ高温はんだが広く用いられてきた。 Solder is generally used for joining metal materials and is an alloy material having a melting temperature range (solidus temperature to liquidus temperature range) of 450 ° C. or less. Conventionally, Sn-37Pb eutectic solder having a melting point of 183 ° C. is generally used as the solder material used in the reflow heat treatment. Sn-90Pb high-temperature solder having a solidus line of 270 ° C. and a liquidus line of 305 ° C. has been widely used.
しかしながら、近年、ＥＵの環境規制（ＷＥＥＥ、ＲｏＨＳ指令）にあるように、Ｐｂの有害性が問題となり、環境汚染を防止する観点から、はんだの鉛フリー化が急速に進んでいる（非特許文献１，２参照）。このような状況の中で、現在、Ｓｎ―３７Ｐｂ共晶はんだの代替としては、融点２２０℃程度のＳｎ―３．０Ａｇ−０．５Ｃｕからなる鉛フリーはんだ（特許文献１，２参照）が用いられ、リフロー熱処理として２４０℃から２６０℃程度の温度範囲のものが一般的となりつつある。一般に、リフロー熱処理条件は、はんだ合金融点＋１０〜５０℃で設定される。 However, in recent years, as in EU environmental regulations (WEEE, RoHS directive), the harmfulness of Pb has become a problem, and from the viewpoint of preventing environmental pollution, lead-free solder has been rapidly advanced (non-patent literature). 1 and 2). Under such circumstances, as a substitute for Sn-37Pb eutectic solder, lead-free solder made of Sn-3.0Ag-0.5Cu having a melting point of about 220 ° C. is currently used (see Patent Documents 1 and 2). In general, a reflow heat treatment having a temperature range of about 240 ° C. to 260 ° C. is becoming common. Generally, the reflow heat treatment conditions are set at a solder alloy melting point + 10 to 50 ° C.
これに対し、高温はんだ材料は、Ａｕ−２０Ｓｎ共晶合金（融点２８０℃）、Ｓｂ−Ｓｎ系合金などが実用化されているが、Ａｕ−Ｓｎ系合金は、機械的に硬く脆い材料で応力緩和性に乏しく、また、極めて高価な材料なので用途が限られること、Ｓｂ−Ｓｎ系合金は、Ｓｂの有害性が指摘されるなど、有力な代替材料が無く、２００６年７月から施行される上記ＲｏＨＳ指令においても、８５％以上Ｐｂを含有する高温はんだは、代替材料が確立されるまでは、適用除外としている。 On the other hand, Au-20Sn eutectic alloy (melting point 280 ° C.), Sb—Sn alloy, etc. have been put to practical use as high-temperature solder materials, but Au—Sn alloy is a mechanically hard and brittle material and stress. Sb-Sn alloys are effective from July 2006 because there are no effective alternative materials such as Sb-Sn based alloys being pointed out that their use is limited because they are poorly relaxed and extremely expensive. Also in the RoHS directive, high temperature solder containing 85% or more of Pb is excluded from application until an alternative material is established.
ところで、上述した融点２２０℃程度のＳｎ主成分の鉛フリーはんだは、Ｓｎ―３７Ｐｂ共晶はんだに比べ、合金の融点が高いことから、当然、使用時に必要なリフロー熱処理条件もより高温になる。しかしながら、最近では、電気・電子機器の熱損傷を抑制するため、出来るだけ低温でのはんだ付けが要望されており、しかも機器が使用中に高温状態となっても再溶融、剥離しない厳しい条件が要求されてきている。低温で溶融接合できるＰｂフリーはんだ材料としては、Ｓｎ―５８Ｂｉ共晶はんだ（融点１３８℃）、Ｉｎ（融点１５７℃）、Ｓｎ―５２Ｉｎ合金はんだ（融点１１８℃）等があるが（特許文献３，４参照）、いずれも融点温度以上になれば、再溶融するので２６０℃耐熱性要求を満たせる材料ではない。 By the way, the lead-free solder containing Sn as a main component and having a melting point of about 220 ° C. has a higher melting point of the alloy than that of Sn-37Pb eutectic solder. However, recently, in order to suppress thermal damage of electrical and electronic equipment, soldering at the lowest possible temperature has been demanded, and there are severe conditions that prevent remelting and peeling even when the equipment becomes hot during use. It has been requested. Pb-free solder materials that can be melt-bonded at low temperatures include Sn-58Bi eutectic solder (melting point 138 ° C.), In (melting point 157 ° C.), Sn-52In alloy solder (melting point 118 ° C.), etc. 4), any of them is not a material that can meet the 260 ° C. heat resistance requirement because it will be melted again if the melting point temperature is exceeded.
本発明者らは、上記の課題を解決する導電性接続材料として、準安定合金相を有し融点を複数有する第１の合金粒子と融点を複数有する第２の合金粒子からなり熱処理により最低融点が上昇する機能性合金粉体からなる接続材料を提案してきた（例えば特許文献５参照）。特許文献５における具体的な該機能性合金粉体としては、Ｃｕ，Ｓｎ，Ａｇ，Ｂｉ，及びＩｎからなる合金に置換Ｓｎメッキした合金粒子と、Ｉｎ，Ｓｎ，Ａｇ，及びＣｕからなる合金粒子の混合物が開示されているが、上記粉体作成には置換Ｓｎメッキプロセスが必要であり、工程が複雑になる上生産性が悪く、製造コストがあがってしまうという課題があった。
本発明は、Ｓｎ―３７Ｐｂ共晶はんだのリフロー熱処理条件よりも低温条件（ピーク温度１４０℃以上）で溶融接合できる高耐熱性の導電性フィラーを提供することを目的とする。また、前記導電性フィラーを用いたはんだペーストを提供することも本発明の目的である。 An object of the present invention is to provide a highly heat-resistant conductive filler that can be melt-bonded at a temperature lower than the reflow heat treatment condition of Sn-37Pb eutectic solder (peak temperature of 140 ° C. or higher). Another object of the present invention is to provide a solder paste using the conductive filler.
本発明者らは、上記特許文献５記載の機能性合金粉体において、Ｓｎ置換メッキ工程を不要にすべく検討を行った結果、本発明をなすにいたった。
すなわち、本発明の一は、第１の金属粒子と第２の金属粒子と第３の金属粒子との混合体からなる導電性フィラーであって、該混合体は示差走査熱量測定（ＤＳＣ）で発熱ピークとして観測される準安定合金相を少なくとも１つと、吸熱ピークとして観測される融点を１１０〜１４０℃に少なくとも１つと１４０〜２００℃に少なくとも１つと３００〜４５０℃に複数有しており、該混合体を１４０〜４００℃で熱処理することにより第２の金属粒子を溶融させ第１の金属粒子及び第３の金属粒子と接合させた後の最低融点が３００〜４００℃にあることを特徴とする導電性フィラーである。上記混合体が第１の金属粒子１００質量部と第２の金属粒子２５〜４００質量部と第３の金属粒子２５〜６００質量部からなり、該第１の金属粒子は、Ｃｕ５０〜８０質量％とＡｇ、Ｂｉ、Ｉｎ、及びＳｎからなる群より選ばれる少なくとも１つ以上の元素２０〜５０質量％の組成を有する合金からなり、該第２の金属粒子は、Ｓｎ３０〜６０質量％とＡｇ、Ｂｉ、Ｃｕ、Ｉｎ、及びＺｎからなる群より選ばれる少なくとも１つ以上の元素４０〜７０質量％の組成を有する合金からなり、該第３の金属粒子は、Ｓｎ３０〜５５質量％とＡｇ２０〜４０質量％とＢｉ、Ｃｕ、Ｉｎ、及びＺｎからなる群より選ばれる少なくとも１つ以上の元素５〜５０質量％の組成を有する合金からなることが好ましい。
本発明の二は、上記の導電性フィラーを含むはんだペーストである。
The inventors of the present invention have studied the functional alloy powder described in Patent Document 5 so as not to require the Sn substitution plating process, and as a result, have come to make the present invention.
That is, one aspect of the present invention is a conductive filler comprising a mixture of first metal particles, second metal particles, and third metal particles, and the mixture is obtained by differential scanning calorimetry (DSC). Having at least one metastable alloy phase observed as an exothermic peak, at least one melting point observed as an endothermic peak at 110-140 ° C, at least one at 140-200 ° C, and a plurality at 300-450 ° C, The mixture has a minimum melting point of 300 to 400 ° C. after the second metal particles are melted by heat treatment at 140 to 400 ° C. and bonded to the first metal particles and the third metal particles. It is a conductive filler. The said mixture consists of 100 mass parts of 1st metal particles, 25-400 mass parts of 2nd metal particles, and 25-600 mass parts of 3rd metal particles, and this 1st metal particle is Cu50-80 mass%. And an alloy having a composition of 20 to 50% by mass of at least one element selected from the group consisting of Ag, Bi, In, and Sn, and the second metal particles include 30 to 60% by mass of Sn, Ag, The third metal particles are made of an alloy having a composition of 40 to 70% by mass of at least one element selected from the group consisting of Bi, Cu, In, and Zn, and the third metal particles include Sn30 to 55% by mass and Ag20 to 40%. It is preferably made of an alloy having a composition of 5% by mass and at least one element selected from the group consisting of Bi, Cu, In, and Zn.
The second of the present invention is a solder paste containing the above conductive filler.
本発明の導電性フィラーは、Ｓｎ―３７Ｐｂ共晶はんだのリフロー熱処理条件よりも低温条件（ピーク温度１４０℃以上）で溶融接合可能な高耐熱性のはんだ材料としての利用が期待できると共に、従来の高温はんだよりも低温で使用できるので、製造コスト、環境負荷を低減できる利点がある。 The conductive filler of the present invention can be expected to be used as a highly heat-resistant solder material that can be melt-bonded at a lower temperature (peak temperature 140 ° C. or higher) than the reflow heat treatment conditions of Sn-37Pb eutectic solder. Since it can be used at a lower temperature than high-temperature solder, there is an advantage that the manufacturing cost and the environmental load can be reduced.
本発明の導電性フィラーとして好ましい態様を例示すると、示差走査熱量測定（ＤＳＣ）で発熱ピークとして観測される準安定合金相と吸熱ピークで観測される融点を３００℃以上に有する第１の金属粒子と、前記発熱ピークを有さず吸熱ピークで観測される融点を１１０〜１４０℃に有する第２の金属粒子と、吸熱ピークで観測させる融点を１４０〜２００℃に少なくとも１つと３００℃〜４５０℃に複数有する第３の金属粒子との混合体があげられる。この混合体は、示差走査熱量測定（ＤＳＣ）で発熱ピークとして観測される準安定合金相と、吸熱ピークで観測される融点を１１０〜１４０℃に少なくとも１つと１４０〜２００℃に少なくとも１つと３００〜４５０℃に複数有している。 As a preferred embodiment of the conductive filler of the present invention, a first metal particle having a metastable alloy phase observed as an exothermic peak by differential scanning calorimetry (DSC) and a melting point observed at an endothermic peak at 300 ° C. or higher. And second metal particles having a melting point observed at an endothermic peak at 110 to 140 ° C. without the exothermic peak, at least one melting point observed at the endothermic peak at 140 to 200 ° C. and 300 ° C. to 450 ° C. And a mixture with a plurality of third metal particles. This mixture has a metastable alloy phase observed as an exothermic peak by differential scanning calorimetry (DSC), a melting point observed at an endothermic peak of at least one at 110-140 ° C, at least one at 140-200 ° C, and 300. It has multiple at ~ 450 ° C.
熱処理により、上記の第２の金属粒子の融点以上に熱履歴が与えられると、該第２の金属粒子が溶融し、上記の第１の金属粒子、及び第３の金属粒子と接合することにより、熱拡散反応が加速的に進み、新たな安定合金相が形成される。また、この際にＤＳＣで発熱ピークとして観測される準安定合金相の存在が熱拡散を助長する効果がある。この新たに形成された安定合金相は、融点が３００℃以上なので、冷却後の最低融点は、３００℃以上となる。従って、例えば、この導電性フィラーを高温はんだに用いれば、プリント基板と電子部品とをはんだ付けする際のリフロー熱処理温度が３００℃未満なら、熱履歴を繰返し与えても、内部接続に使用される高温はんだが再溶融することはない。 When a heat history is given to the melting point of the second metal particles or more by the heat treatment, the second metal particles are melted and bonded to the first metal particles and the third metal particles. The thermal diffusion reaction proceeds at an accelerated rate, and a new stable alloy phase is formed. At this time, the presence of a metastable alloy phase observed as an exothermic peak by DSC has an effect of promoting thermal diffusion. Since this newly formed stable alloy phase has a melting point of 300 ° C. or higher, the minimum melting point after cooling is 300 ° C. or higher. Therefore, for example, if this conductive filler is used for high-temperature solder, if the reflow heat treatment temperature when soldering the printed circuit board and the electronic component is less than 300 ° C., it can be used for internal connection even if heat history is repeatedly applied. High-temperature solder does not remelt.
本発明の導電性フィラーを構成する第１の金属粒子は、Ｃｕ５０〜８０質量％とＡｇ、Ｂｉ、Ｉｎ、及びＳｎからなる群より選ばれる少なくとも１つ以上の元素２０〜５０質量％の組成を有する合金からなることが好ましく、第２の金属粒子は、Ｓｎ３０〜６０質量％とＡｇ、Ｂｉ、Ｃｕ、Ｉｎ、及びＺｎからなる群より選ばれる少なくとも１つ以上の元素４０〜７０質量％の組成を有する合金からなることが好ましく、第３の金属粒子は、Ｓｎ３０〜５５質量％とＡｇ２０〜４０質量％とＢｉ、Ｃｕ、Ｉｎ、及びＺｎからなる群より選ばれる少なくとも１つ以上の元素５〜５０質量％の組成を有する合金からなることが好ましい。
The 1st metal particle which comprises the electroconductive filler of this invention has the composition of 20-50 mass% of at least 1 or more elements chosen from the group which consists of Cu50-80 mass% and Ag, Bi, In, and Sn. Preferably, the second metal particles are composed of Sn 30 to 60% by mass and at least one element 40 to 70% by mass selected from the group consisting of Ag, Bi, Cu, In, and Zn. It is preferable that the third metal particles include Sn 30 to 55 mass%,
尚、第１の金属粒子と第２の金属粒子と第３の金属粒子の混合比は、第１の金属粒子１００質量部に対して、第２の金属粒子２５〜４００質量部、第３の金属粒子２５〜６００質量部が好ましく、更には、第１の金属粒子１００質量部に対して、第２の金属粒子５０〜２００質量部、第３の金属粒子１００〜３００質量部がより好ましい。
上記金属粒子の粒子サイズは、用途に応じて様々であるが、例えば、はんだペースト用途では、印刷性を重視して、平均粒径で２〜４０μｍの比較的真球度の高い粒子を使い、導電性接着剤用途では、粒子の接触面積を増やすため、異形粒子を使うのが一般的である。
また、通常、金属粒子は表面酸化されていることが多い。従って、上述の用途における熱処理による溶融、熱拡散を促進するためには、酸化膜を除去する活性剤を配合したり、加圧したりする条件が好ましい。
The mixing ratio of the first metal particles, the second metal particles, and the third metal particles is 25 to 400 parts by mass of the second metal particles and 100% by mass of the first metal particles. The metal particles are preferably 25 to 600 parts by mass, and more preferably 50 to 200 parts by mass of the second metal particles and 100 to 300 parts by mass of the third metal particles with respect to 100 parts by mass of the first metal particles.
Although the particle size of the metal particles varies depending on the application, for example, in solder paste applications, emphasizing printability, using particles with a relatively high sphericity of 2 to 40 μm in average particle diameter, For conductive adhesive applications, it is common to use irregularly shaped particles to increase the contact area of the particles.
In general, metal particles are often surface oxidized. Accordingly, in order to promote melting and thermal diffusion by the heat treatment in the above-mentioned application, conditions for blending or pressurizing an activator for removing the oxide film are preferable.
本発明の導電性フィラーを構成する第１、第２及び第３の金属粒子の製造方法としては、該金属粒子内に準安定合金相や安定合金相を形成させるために、急冷凝固法である不活性ガスアトマイズ法を採用することが望ましい。また、ガスアトマイズ法では、通常、窒素ガス、アルゴンガス、ヘリウムガス等の不活性ガスが使用されるが、本発明に関しては、ヘリウムガスを用いることが好ましく、冷却速度は、５００℃／秒以上が好ましい。 The method for producing the first, second and third metal particles constituting the conductive filler of the present invention is a rapid solidification method in order to form a metastable alloy phase or a stable alloy phase in the metal particles. It is desirable to employ an inert gas atomization method. In the gas atomization method, an inert gas such as nitrogen gas, argon gas or helium gas is usually used. However, helium gas is preferably used in the present invention, and the cooling rate is 500 ° C./second or more. preferable.
本発明のはんだペーストは、本発明の導電性フィラー、並びにロジン、溶剤、活性剤、及び増粘剤等の成分からなるフラックスで構成される。はんだペーストにおける該導電性フィラーの含有率としては、８５〜９５質量％が好ましい。フラックスは、金属粒子からなる導電性フィラーの表面処理に最適で、該金属粒子の溶融、及び熱拡散を促進する。フラックスとしては、公知の材料が使用できるが、更に有機アミンを加えるとより効果的である。 The solder paste of this invention is comprised with the flux which consists of components, such as the electroconductive filler of this invention, and a rosin, a solvent, an activator, and a thickener. The content of the conductive filler in the solder paste is preferably 85 to 95% by mass. The flux is optimal for the surface treatment of the conductive filler made of metal particles, and promotes melting and thermal diffusion of the metal particles. A known material can be used as the flux, but it is more effective when an organic amine is further added.
以下、本発明を実施例に基づいて説明する。
［実施例１］
（１）第１の金属粒子の製造
Ｃｕ粒子６．５ｋｇ（純度９９質量％以上）、Ｓｎ粒子１．５ｋｇ（純度９９質量％以上）、Ａｇ粒子１．０ｋｇ（純度９９質量％以上）、Ｂｉ粒子０．５ｋｇ（純度９９質量％以上）、Ｉｎ粒子０．５ｋｇ（純度９９質量％以上）を黒鉛坩堝に入れ、９９体積％以上のヘリウム雰囲気で、高周波誘導加熱装置により１４００℃まで加熱、融解した。次に、この溶融金属を坩堝の先端より、ヘリウムガス雰囲気の噴霧槽内に導入した後、坩堝先端付近に設けられたガスノズルから、ヘリウムガス（純度９９体積％以上、酸素濃度０．１体積％未満、圧力２．５ＭＰａ）を噴出してアトマイズを行い、第１の金属粒子を作製した。この時の冷却速度は２６００℃／秒とした。
Hereinafter, the present invention will be described based on examples.
[Example 1]
(1) Production of first metal particles 6.5 kg of Cu particles (purity 99 mass% or more), 1.5 kg of Sn particles (purity 99 mass% or more), 1.0 kg of Ag particles (purity 99 mass% or more), Bi 0.5 kg of particles (purity 99% by mass or more) and 0.5 kg of In particles (purity 99% by mass or more) are placed in a graphite crucible and heated and melted to 1400 ° C. with a high-frequency induction heating apparatus in a helium atmosphere of 99% by volume or more. did. Next, after introducing the molten metal from the tip of the crucible into a spray tank in a helium gas atmosphere, helium gas (purity 99 vol% or more, oxygen concentration 0.1 vol%) is supplied from a gas nozzle provided near the crucible tip. Less than the pressure of 2.5 MPa), atomization was performed to produce first metal particles. The cooling rate at this time was 2600 ° C./second.
得られた第１の金属粒子を走査型電子顕微鏡（日立製作所（株）製：Ｓ−２７００）で観察したところ球状であった。この金属粒子を気流式分級機（日清エンジニアリング（株）製：ＴＣ−１５Ｎ）を用いて、１０μｍの設定で分級した後に、そのアンダーカット粉を回収した。この回収された第１の金属粒子の体積平均粒径は２．７μｍであった。このようにして得られた第１の金属粒子を試料とし、島津製作所（株）製「ＤＳＣ−５０」を用い、窒素雰囲気下、昇温速度１０℃／分の条件で、３０〜６００℃の範囲において示差走査熱量測定を行った。その結果、得られた第１の金属粒子には、４９７℃、５１７℃の吸熱ピークが存在し、複数の融点を有することが確認できた。また、１５９℃、２５０℃の発熱ピークが存在し、準安定合金相を複数有することが確認できた。尚、ＤＳＣ測定にいては、熱量が±１．５Ｊ／ｇ以上あるものを第１の金属粒子由来のピークとして定量し、それ未満は分析精度の観点から除外した。 When the obtained 1st metal particle was observed with the scanning electron microscope (Hitachi, Ltd. product: S-2700), it was spherical. The metal particles were classified using an airflow classifier (manufactured by Nissin Engineering Co., Ltd .: TC-15N) at a setting of 10 μm, and then the undercut powder was recovered. The collected first metal particles had a volume average particle size of 2.7 μm. The first metal particles thus obtained were used as samples, and “DSC-50” manufactured by Shimadzu Corporation was used, and the temperature was 30 to 600 ° C. under a temperature increase rate of 10 ° C./min in a nitrogen atmosphere. Differential scanning calorimetry was performed over the range. As a result, it was confirmed that the obtained first metal particles had endothermic peaks at 497 ° C. and 517 ° C. and had a plurality of melting points. Moreover, the exothermic peak of 159 degreeC and 250 degreeC existed, and it has confirmed that it had multiple metastable alloy phases. In the DSC measurement, a sample having a calorific value of ± 1.5 J / g or more was quantified as a peak derived from the first metal particles, and less than that was excluded from the viewpoint of analysis accuracy.
（２）第２の金属粒子の製造
Ｃｕ粒子１．５ｋｇ（純度９９質量％以上）、Ｓｎ粒子３．７５ｋｇ（純度９９質量％以上）、Ａｇ粒子１．０ｋｇ（純度９９質量％以上）、Ｉｎ粒子３．７５ｋｇ（純度９９質量％以上）を黒鉛坩堝に入れ、９９体積％以上のヘリウム雰囲気で、高周波誘導加熱装置により１４００℃まで加熱、融解した。次に、この溶融金属を坩堝の先端より、ヘリウムガス雰囲気の噴霧槽内に導入した後、坩堝先端付近に設けられたガスノズルから、ヘリウムガス（純度９９体積％以上、酸素濃度０．１体積％未満、圧力２．５ＭＰａ）を噴出してアトマイズを行うことにより、第２の金属粒子を作製した。この時の冷却速度は２６００℃／秒とした。
(2) Production of second metal particles 1.5 kg of Cu particles (purity 99% by mass or more), 3.75 kg of Sn particles (purity 99% by mass or more), 1.0 kg of Ag particles (purity 99% by mass or more), In 3.75 kg (purity 99% by mass or more) of particles were placed in a graphite crucible and heated and melted to 1400 ° C. with a high-frequency induction heating apparatus in a helium atmosphere of 99% by volume or more. Next, after introducing the molten metal from the tip of the crucible into a spray tank in a helium gas atmosphere, helium gas (purity 99 vol% or more, oxygen concentration 0.1 vol%) is supplied from a gas nozzle provided near the crucible tip. The second metal particles were produced by performing atomization by ejecting a pressure of less than 2.5 MPa. The cooling rate at this time was 2600 ° C./second.
得られた第２の金属粒子を走査型電子顕微鏡（日立製作所（株）製：Ｓ−２７００）で観察したところ球状であった。この金属粒子を気流式分級機（日清エンジニアリング（株）製：ＴＣ−１５Ｎ）を用いて、１５μｍの設定で分級した後に、そのオーバーカット粉を３０μｍの設定でもう一度分級して得られたアンダーカット粉を回収した。この回収された第２の金属粒子の体積平均粒径は１３．９μｍであった。このようにして得られた第２の金属粒子を試料とし、島津製作所（株）製「ＤＳＣ−５０」を用い、窒素雰囲気下、昇温速度１０℃／分の条件で、３０〜６００℃の範囲において示差走査熱量測定を行った。その結果、得られた第２の金属粒子は、示差走査熱量測定による１３３℃の吸熱ピークが存在し、融点１２４℃（融解開始温度：通常、固相線温度と表示させる温度）を有することが確認できた。また、特徴的な発熱ピークは存在しなかった。尚、ＤＳＣ測定にいては、熱量が±１．５Ｊ／ｇ以上あるものを第２の金属粒子由来のピークとして定量し、それ未満は分析精度の観点から除外した。 When the obtained 2nd metal particle was observed with the scanning electron microscope (Hitachi Ltd. make: S-2700), it was spherical. This metal particle was classified using an airflow classifier (manufactured by Nissin Engineering Co., Ltd .: TC-15N) at a setting of 15 μm, and then the undercut obtained by classifying the overcut powder again at a setting of 30 μm. Cut powder was collected. The volume average particle diameter of the recovered second metal particles was 13.9 μm. The second metal particles thus obtained were used as samples, and “DSC-50” manufactured by Shimadzu Corporation was used, and the temperature was 30 to 600 ° C. under a nitrogen atmosphere under a temperature rising rate of 10 ° C./min. Differential scanning calorimetry was performed over the range. As a result, the obtained second metal particles have an endothermic peak at 133 ° C. by differential scanning calorimetry, and have a melting point of 124 ° C. (melting start temperature: usually a temperature indicated as a solidus temperature). It could be confirmed. There was no characteristic exothermic peak. In the DSC measurement, a sample having a calorific value of ± 1.5 J / g or more was quantified as a peak derived from the second metal particle, and less than that was excluded from the viewpoint of analysis accuracy.
（３）第３の金属粒子の製造
Ｃｕ粒子１．０ｋｇ（純度９９質量％以上）、Ｓｎ粒子４．８ｋｇ（純度９９質量％以上）、Ａｇ粒子３．２ｋｇ（純度９９質量％以上）、Ｂｉ粒子０．５ｋｇ（純度９９質量％以上）、Ｉｎ粒子０．５ｋｇ（純度９９質量％以上）を黒鉛坩堝に入れ、９９体積％以上のヘリウム雰囲気で、高周波誘導加熱装置により１４００℃まで加熱、融解した。次に、この溶融金属を坩堝の先端より、ヘリウムガス雰囲気の噴霧槽内に導入した後、坩堝先端付近に設けられたガスノズルから、ヘリウムガス（純度９９体積％以上、酸素濃度０．１体積％未満、圧力２．５ＭＰａ）を噴出してアトマイズを行い、第３の金属粒子を作製した。この時の冷却速度は２６００℃／秒とした。
(3) Production of third metal particles: Cu particles 1.0 kg (purity 99% by mass or more), Sn particles 4.8 kg (purity 99% by mass or more), Ag particles 3.2 kg (purity 99% by mass or more), Bi 0.5 kg of particles (purity 99% by mass or more) and 0.5 kg of In particles (purity 99% by mass or more) are placed in a graphite crucible and heated and melted to 1400 ° C. with a high-frequency induction heating apparatus in a helium atmosphere of 99% by volume or more. did. Next, after introducing the molten metal from the tip of the crucible into a spray tank in a helium gas atmosphere, helium gas (purity 99 vol% or more, oxygen concentration 0.1 vol%) is supplied from a gas nozzle provided near the crucible tip. Less than the pressure of 2.5 MPa) and atomization was performed to produce third metal particles. The cooling rate at this time was 2600 ° C./second.
得られた第３の金属粒子を走査型電子顕微鏡（日立製作所（株）製：Ｓ−２７００）で観察したところ球状であった。この金属粒子を気流式分級機（日清エンジニアリング（株）製：ＴＣ−１５Ｎ）を用いて、５μｍの設定で分級した後に、そのアンダーカット粉を回収した。この回収された第３の金属粒子の体積平均粒径は１．８μｍであった。このようにして得られた第３の金属粒子を試料とし、島津製作所（株）製「ＤＳＣ−５０」を用い、窒素雰囲気下、昇温速度１０℃／分の条件で、３０〜６００℃の範囲において示差走査熱量測定を行った。その結果、得られた第３の金属粒子には、１９５℃、３５９℃、４０２℃の吸熱ピークが存在し、複数の融点を有することが確認できた。尚、ＤＳＣ測定にいては、熱量が±１．５Ｊ／ｇ以上あるものを第３の金属粒子由来のピークとして定量し、それ未満は分析精度の観点から除外した。 The obtained third metal particles were spherical when observed with a scanning electron microscope (manufactured by Hitachi, Ltd .: S-2700). The metal particles were classified using an airflow classifier (manufactured by Nisshin Engineering Co., Ltd .: TC-15N) at a setting of 5 μm, and then the undercut powder was recovered. The volume average particle size of the recovered third metal particles was 1.8 μm. The third metal particles thus obtained were used as samples, and “DSC-50” manufactured by Shimadzu Corporation was used, and the temperature was 30 to 600 ° C. under a nitrogen atmosphere under a temperature rising rate of 10 ° C./min. Differential scanning calorimetry was performed over the range. As a result, it was confirmed that the obtained third metal particles had endothermic peaks at 195 ° C., 359 ° C. and 402 ° C. and had a plurality of melting points. In the DSC measurement, a sample having a calorific value of ± 1.5 J / g or more was quantified as a peak derived from the third metal particle, and less than that was excluded from the viewpoint of analysis accuracy.
（４）熱処理による融点変化の確認
上記第１の金属粒子、第２の金属粒子、第３の金属粒子を重量比１００：８９：１９６で混合した導電性フィラー（平均粒径２．２μｍ）を試料とし、島津製作所（株）製「ＤＳＣ−５０」を用い、窒素雰囲気下、昇温速度１０℃／分の条件で、３０〜６００℃の範囲において示差走査熱量測定を行った。この測定により得られたＤＳＣチャートを図１に示す。この図に示すように、１３２℃、１９５℃、３７９℃に吸熱ピークが存在することが確認された。１３２℃吸熱ピークは、融点１２８℃（融解開始温度：固相線温度と表示させる温度）である。また、特徴的に２９６℃に発熱ピークが存在していた。尚、ＤＳＣ測定にいては、熱量が±１．５Ｊ／ｇ以上あるものを導電性フィラー由来のピークとして定量し、それ未満は分析精度の観点から除外した。
(4) Confirmation of melting point change by heat treatment Conductive filler (average particle size 2.2 μm) obtained by mixing the first metal particles, the second metal particles, and the third metal particles in a weight ratio of 100: 89: 196. Using a DSC-50 manufactured by Shimadzu Corporation as a sample, differential scanning calorimetry was performed in a temperature range of 30 to 600 ° C. under a nitrogen atmosphere under a temperature rising rate of 10 ° C./min. The DSC chart obtained by this measurement is shown in FIG. As shown in this figure, it was confirmed that endothermic peaks exist at 132 ° C., 195 ° C., and 379 ° C. The 132 ° C. endothermic peak has a melting point of 128 ° C. (melting start temperature: temperature indicated as solidus temperature). Also, an exothermic peak existed at 296 ° C. characteristically. In the DSC measurement, a sample having a calorific value of ± 1.5 J / g or more was quantified as a peak derived from the conductive filler, and less than that was excluded from the viewpoint of analysis accuracy.
次に、前記導電性フィラー９０．５質量％、ロジン系フラックス６．６１質量％、トリエタノールアミン（酸化膜除去剤）１．６５質量％、ステアリン酸（活性剤）０．４１質量％、及びエチレングリコールモノヘキシルエーテル（溶剤）０．８３質量％を混合し、脱泡混練機（松尾産業社（株）製：ＳＮＢ−３５０）にかけてはんだペーストを作製した。
得られたはんだペーストをアルミナ基板に載せ、リフロー炉で空気雰囲気下にて、ピーク温度１８０℃で熱処理した。この熱処理後のはんだペーストを試料とし、島津製作所（株）製「ＤＳＣ−５０」を用い、窒素雰囲気下、昇温速度１０℃／分の条件で、３０〜６００℃の範囲において示差走査熱量測定を行った。この測定により得られたＤＳＣチャートを図２に示す。この図に示すように、３７８℃に吸熱ピークが存在し、１３２℃、１９５℃の吸熱ピークは消失していることが確認された。３７８℃吸熱ピークは、融点３２０℃（融解開始温度：固相線温度と表示させる温度）である。すなわち、ピーク温度１８０℃のリフロー熱処理により、導電性フィラーの最低融点が１２８℃から３２０℃に上昇したことが確認された。尚、ＤＳＣ測定にいては、熱量が±１．５Ｊ／ｇ以上あるものを導電性フィラー由来のピークとして定量し、それ未満は分析精度の観点から除外した。
Next, the conductive filler 90.5% by mass, rosin flux 6.61% by mass, triethanolamine (oxide film removing agent) 1.65% by mass, stearic acid (activator) 0.41% by mass, and Ethylene glycol monohexyl ether (solvent) 0.83% by mass was mixed and applied to a defoaming kneader (manufactured by Matsuo Sangyo Co., Ltd .: SNB-350) to prepare a solder paste.
The obtained solder paste was placed on an alumina substrate and heat-treated at a peak temperature of 180 ° C. in an air atmosphere in a reflow furnace. Using the solder paste after this heat treatment as a sample, differential scanning calorimetry in the range of 30 to 600 ° C. under a temperature increase rate of 10 ° C./min under a nitrogen atmosphere using “DSC-50” manufactured by Shimadzu Corporation Went. The DSC chart obtained by this measurement is shown in FIG. As shown in this figure, it was confirmed that an endothermic peak was present at 378 ° C. and the endothermic peaks at 132 ° C. and 195 ° C. were lost. The 378 ° C. endothermic peak has a melting point of 320 ° C. (melting start temperature: temperature indicated as solidus temperature). That is, it was confirmed that the minimum melting point of the conductive filler increased from 128 ° C. to 320 ° C. by the reflow heat treatment at the peak temperature of 180 ° C. In the DSC measurement, a sample having a calorific value of ± 1.5 J / g or more was quantified as a peak derived from the conductive filler, and less than that was excluded from the viewpoint of analysis accuracy.
（５）接合強度、高耐熱性の確認
上記はんだペーストをＣｕ基板に２ｍｍ×３．５ｍｍで印刷し、２ｍｍ×２ｍｍチップを搭載後、リフロー炉で空気雰囲気下にて、ピーク温度１８０℃で熱処理した。印刷パターン形成は、印刷機としてマイクロテック（株）製の「ＭＴ−３２０ＴＶ」を用い、版は、スクリーンマスクを用いた。スクリーンマスクの開孔は、２ｍｍ×２ｍｍであり、厚みは、５０μｍである。印刷条件は、印刷速度：２０ｍｍ／秒、印圧：０．１ＭＰａ、スキージ圧：０．２ＭＰａ、背圧：０．１ＭＰａ、アタック角度：２０°、クリアランス：１ｍｍ、印刷回数１回とした。また、チップは、厚みが０．６ｍｍで、接合面にＡｕ／Ｎｉ／Ｃｒ（３０００／２０００／５００Å）スパッタリングしてあるＳｉチップを用いた。次に、常温で、チップの剪断方向の接合強度をプッシュ・プルゲージにより、押し速度１０ｍｍ／ｍｉｎで測定し、単位面積に換算したところ１１ＭＰaであった。更に、前記と同じ方法で作製した基板をホットプレート上で２６０℃まで加熱し、２６０℃で１分間保持した状態で、前記と同じ方法で、剪断方向の接合強度を測定したところ、３ＭＰａであり、２６０℃でも接合強度を保持できる耐熱性を確認できた。
(5) Confirmation of bonding strength and high heat resistance The solder paste is printed on a Cu substrate at 2 mm x 3.5 mm, mounted with a 2 mm x 2 mm chip, and then heat-treated at a peak temperature of 180 ° C in an air atmosphere in a reflow oven. did. For the printing pattern formation, “MT-320TV” manufactured by Microtech Co., Ltd. was used as a printing machine, and a screen mask was used for the plate. The aperture of the screen mask is 2 mm × 2 mm, and the thickness is 50 μm. The printing conditions were printing speed: 20 mm / second, printing pressure: 0.1 MPa, squeegee pressure: 0.2 MPa, back pressure: 0.1 MPa, attack angle: 20 °, clearance: 1 mm, and number of printings once. Further, a Si chip having a thickness of 0.6 mm and Au / Ni / Cr (3000/2000/500 mm) sputtered on the bonding surface was used. Next, the bonding strength in the shear direction of the chip was measured at a normal pressure at a pressing speed of 10 mm / min with a push-pull gauge and converted to a unit area of 11 MPa. Furthermore, when the substrate produced by the same method as described above was heated to 260 ° C. on a hot plate and held at 260 ° C. for 1 minute, the joint strength in the shear direction was measured by the same method as described above, and it was 3 MPa. The heat resistance capable of maintaining the bonding strength even at 260 ° C. was confirmed.
（６）耐イオンマイグレーション性及び絶縁信頼性の確認
次に上記はんだペーストを用いて、ガラスエポキシ基板上に「ＪＩＳ Ｚ ３１９７」に準拠した「櫛形電極」のパターンを印刷した。このパターンをリフロー炉で空気雰囲気下にてピーク温度１８０℃で熱処理することにより、パターンを硬化させて「櫛形電極」を形成した。次に熱処理で得られた「櫛形電極」を用いて、「ＪＩＳ Ｚ ３１９７」の方法でマイグレーション試験を実施した。すなわち、各「櫛形電極」を温度８５℃、湿度８５％の恒温恒湿槽内に入れ、５０Ｖの電圧を付与した状態で１０００時間保持した。その後、拡大鏡で「櫛形電極」の状態を観察したところ、いずれの基板上の「櫛形電極」についても、デンドライト（樹枝状金属）の生成は認められなかった。
(6) Confirmation of Ion Migration Resistance and Insulation Reliability Next, using the solder paste, a “comb electrode” pattern based on “JIS Z 3197” was printed on a glass epoxy substrate. This pattern was heat-treated in a reflow oven in an air atmosphere at a peak temperature of 180 ° C. to cure the pattern and form a “comb electrode”. Next, using the “comb-shaped electrode” obtained by the heat treatment, a migration test was carried out by the method of “JIS Z 3197”. That is, each “comb-shaped electrode” was placed in a constant temperature and humidity chamber having a temperature of 85 ° C. and a humidity of 85%, and held for 1000 hours with a voltage of 50 V applied. Thereafter, when the state of the “comb electrode” was observed with a magnifying glass, no dendrite (dendritic metal) was generated in any of the “comb electrodes” on any substrate.
また、前記各条件で熱処理されて得られた「櫛形電極」を用いて、「ＪＩＳ Ｚ ３１９７」の方法で絶縁抵抗試験を実施した。すなわち、各「櫛形電極」を、温度８５℃、湿度８５％の恒温恒湿槽内に入れて、５０Ｖの電圧を付与した状態で１０００時間保持した後、その抵抗値を測定した。また、この試験前にも各「櫛形電極」の抵抗値を測定した。その結果、試験前の抵抗値が１．１×１０10Ωであり、試験後の抵抗値が８．０×１０10Ωであった。いずれの抵抗値も、１．０×１０8 Ω以上であり、絶縁抵抗値の低下は見られなかった。 Further, an insulation resistance test was performed by the method of “JIS Z 3197” using “comb-shaped electrodes” obtained by heat treatment under the above-mentioned conditions. That is, each “comb-shaped electrode” was placed in a constant temperature and humidity chamber having a temperature of 85 ° C. and a humidity of 85%, and kept at a voltage of 50 V for 1000 hours, and then the resistance value was measured. In addition, the resistance value of each “comb electrode” was also measured before this test. As a result, the resistance value before the test was 1.1 × 10 10 Ω, and the resistance value after the test was 8.0 × 10 10 Ω. All the resistance values were 1.0 × 10 8 Ω or more, and no decrease in the insulation resistance value was observed.
（７）導電性の確認
次に、一対のＡｇ／Ｐｄ電極を形成したセラミック基板上に、該電極間を接続するように上記はんだペーストを印刷後、リフロー炉で空気雰囲気下にて、ピーク温度１８０℃で熱処理した。印刷パターン形成は、印刷機としてマイクロテック（株）製の「ＭＴ−３２０ＴＶ」を用い、版は、スクリーンマスクを用いた。スクリーンマスクの開孔は、２ｍｍ×２ｍｍであり、膜厚は５０μｍである。印刷条件は、印刷速度：２０ｍｍ／秒、印圧：０．１ＭＰａ、スキージ圧：０．２ＭＰａ、背圧：０．１ＭＰａ、アタック角度：２０°、クリアランス：１ｍｍ、印刷回数１回とした。これにより得られた印刷パターンの抵抗値を２端子法により測定した。また、配線の長さ、幅、厚みから体積を算出した。この測定値と算出値から印刷パターンの体積抵抗値を計算したところ、２．６×１０-4Ω・ｃｍであった。
(7) Confirmation of conductivity Next, on the ceramic substrate on which a pair of Ag / Pd electrodes are formed, after printing the solder paste so as to connect the electrodes, the peak temperature is measured in an air atmosphere in a reflow furnace. Heat treatment was performed at 180 ° C. For the printing pattern formation, “MT-320TV” manufactured by Microtech Co., Ltd. was used as a printing machine, and a screen mask was used for the plate. The aperture of the screen mask is 2 mm × 2 mm, and the film thickness is 50 μm. The printing conditions were printing speed: 20 mm / second, printing pressure: 0.1 MPa, squeegee pressure: 0.2 MPa, back pressure: 0.1 MPa, attack angle: 20 °, clearance: 1 mm, and number of printings once. The resistance value of the printed pattern thus obtained was measured by the two-terminal method. The volume was calculated from the length, width, and thickness of the wiring. When the volume resistance value of the printed pattern was calculated from the measured value and the calculated value, it was 2.6 × 10 −4 Ω · cm.
［比較例１］
Ｓｎ―３７Ｐｂ共晶はんだ粒子（平均粒径３２．５μｍ）を９０．５質量％、ロジン系フラックス６．６１質量％、トリエタノールアミン（酸化膜除去剤）１．６５質量％、ステアリン酸（活性剤）０．４１質量％及びエチレングリコールモノヘキシルエーテル（溶剤）０．８３質量％を混合し、脱泡混練機（松尾産業社（株）製：ＳＮＢ−３５０）、３本ロールにかけてはんだペーストを作製した後に、実施例１と同様の条件で、Ｃｕ基板に２ｍｍ×３．５ｍｍで印刷し、２ｍｍ×２ｍｍチップを搭載後、リフロー炉で空気雰囲気下にて、ピーク温度１８０℃で熱処理して基板を作製した。次に、常温で、実施例１と同じ方法で、チップの剪断方向の接合強度を測定し、単位面積に換算したところ５ＭＰaであった。また、更に、実施例１と同じ方法で作製した基板をホットプレート上で２６０℃まで加熱し、２６０℃で１分間保持した状態で、実施例１と同じ方法で、剪断方向の接合強度を測定しようとしたところ、はんだペーストが再溶融して、チップが浮いてしまい接合強度は測定できなかった。
[Comparative Example 1]
90.5% by mass of Sn-37Pb eutectic solder particles (average particle size 32.5 μm), 6.61% by mass of rosin flux, 1.65% by mass of triethanolamine (oxide removal agent), stearic acid (active Agent) 0.41% by mass and ethylene glycol monohexyl ether (solvent) 0.83% by mass are mixed, and the defoaming kneader (Matsuo Sangyo Co., Ltd .: SNB-350) is applied to three rolls to apply the solder paste. After fabrication, under the same conditions as in Example 1, printed on a Cu substrate at 2 mm × 3.5 mm, mounted with a 2 mm × 2 mm chip, and then heat treated at a peak temperature of 180 ° C. in an air atmosphere in a reflow oven. A substrate was produced. Next, the bonding strength in the shear direction of the chip was measured at room temperature by the same method as in Example 1, and converted to a unit area of 5 MPa. Further, the bonding strength in the shear direction was measured by the same method as in Example 1 while the substrate manufactured by the same method as in Example 1 was heated to 260 ° C. on a hot plate and held at 260 ° C. for 1 minute. As a result, the solder paste remelted and the chip floated, and the joint strength could not be measured.
［比較例２］
Ｓｎ−３．０Ａｇ−０．５Ｃｕ鉛フリーはんだ粒子（平均粒径１７．４μｍ）を９０．５質量％、ロジン系フラックス６．６１質量％、トリエタノールアミン（酸化膜除去剤）１．６５質量％、ステアリン酸（活性剤）０．４１質量％及びエチレングリコールモノヘキシルエーテル（溶剤）０．８３質量％を混合し、脱泡混練機（松尾産業社（株）製：ＳＮＢ−３５０）、３本ロールにかけてはんだペーストを作製した後に、上記と同様の条件で、Ｃｕ基板に２ｍｍ×３．５ｍｍで印刷し、２ｍｍ×２ｍｍチップを搭載後、リフロー炉で空気雰囲気下にて、ピーク温度１８０℃で熱処理して基板を作製した。次に、常温で、前記と同じ方法で、チップの剪断方向の接合強度を測定し、単位面積に換算したところ１ＭＰaであった。また、更に、前記と同じ方法で作製した基板をホットプレート上で２６０℃まで加熱し、２６０℃で１分間保持した状態で、前記と同じ方法で、剪断方向の接合強度を測定しようとしたところ、はんだペーストが再溶融して、チップが浮いてしまい接合強度は測定できなかった。
[Comparative Example 2]
Sn-3.0Ag-0.5Cu lead-free solder particles (average particle size 17.4 μm) 90.5% by mass, rosin flux 6.61% by mass, triethanolamine (oxide film removing agent) 1.65% by mass %, Stearic acid (activator) 0.41% by mass and ethylene glycol monohexyl ether (solvent) 0.83% by mass, defoaming kneader (Matsuo Sangyo Co., Ltd .: SNB-350), 3 After producing the solder paste over this roll, under the same conditions as described above, printing on a Cu substrate at 2 mm × 3.5 mm, mounting a 2 mm × 2 mm chip, and then at a peak temperature of 180 ° C. in an air atmosphere in a reflow oven The substrate was fabricated by heat treatment. Next, the bonding strength in the shear direction of the chip was measured at room temperature by the same method as described above, and it was 1 MPa when converted to a unit area. Furthermore, when the substrate manufactured by the same method as described above was heated to 260 ° C. on a hot plate and held at 260 ° C. for 1 minute, the bond strength in the shear direction was measured by the same method as described above. The solder paste remelted and the chip floated, and the joint strength could not be measured.
[結果まとめ]
以上、説明したように本発明の導電性フィラーを用いれば、従来のＳｎ―３７Ｐｂ共晶はんだのリフロー熱処理条件よりも低温条件（ピーク温度１４０℃以上）で溶融接合できる高耐熱性のはんだ材料が開発できる。また、はんだペーストとしても、耐イオンマイグレーション性、絶縁信頼性、導電性に優れた材料であることが確認できた。
[Result Summary]
As described above, if the conductive filler of the present invention is used, a highly heat-resistant solder material that can be melt-bonded at a lower temperature condition (peak temperature of 140 ° C. or higher) than the conventional reflow heat treatment conditions of Sn-37Pb eutectic solder can be obtained. Can be developed. It was also confirmed that the solder paste was a material excellent in ion migration resistance, insulation reliability, and conductivity.
本発明の導電性フィラーは、鉛フリー材料であり、Ｓｎ―３７Ｐｂ共晶はんだのリフロー熱処理条件よりも低温条件（ピーク温度１４０℃以上）で溶融接合可能な、高耐熱性のはんだ材料としての利用が期待できる。また、従来の高温はんだよりも低温で使用できるので、製造コスト、環境負荷を低減できる利点がある。 The conductive filler of the present invention is a lead-free material and can be used as a highly heat-resistant solder material that can be melt-bonded at a lower temperature (peak temperature of 140 ° C. or higher) than the reflow heat treatment condition of Sn-37Pb eutectic solder. Can be expected. Moreover, since it can be used at a lower temperature than conventional high-temperature solder, there is an advantage that the manufacturing cost and the environmental load can be reduced.
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| JP2001184949A (en) * | 1999-12-24 | 2001-07-06 | Asahi Kasei Corp | Anisotropy conductive material |
| JP3558063B2 (en) * | 2000-06-12 | 2004-08-25 | 株式会社日立製作所 | Solder |
| WO2002028574A1 (en) * | 2000-10-02 | 2002-04-11 | Asahi Kasei Kabushiki Kaisha | Functional alloy particles |
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| JP2009088431A (en) * | 2007-10-03 | 2009-04-23 | Asahi Kasei Electronics Co Ltd | Paste for forming bump, and bump structure |
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| EP2239345A4 (en) * | 2008-01-23 | 2013-06-19 | Taiho Kogyo Co Ltd | Process for production of sintered copper alloy sliding material and sintered copper alloy sliding material |
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| JP2009200285A (en) * | 2008-02-22 | 2009-09-03 | Asahi Kasei E-Materials Corp | Bump and bump connection structure |
| JP5643972B2 (en) * | 2009-02-25 | 2014-12-24 | 株式会社弘輝 | Metal filler, low-temperature connection lead-free solder, and connection structure |
| JP2012125791A (en) * | 2010-12-15 | 2012-07-05 | Asahi Kasei E-Materials Corp | Filler metal and lead-free solder comprising the same |
| JP2014207307A (en) * | 2013-04-12 | 2014-10-30 | シチズン電子株式会社 | Led device and method of manufacturing the same |
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