JP3759383B2 - Conductive resin paste and semiconductor device - Google Patents
Conductive resin paste and semiconductor device Download PDFInfo
- Publication number
- JP3759383B2 JP3759383B2 JP2000232796A JP2000232796A JP3759383B2 JP 3759383 B2 JP3759383 B2 JP 3759383B2 JP 2000232796 A JP2000232796 A JP 2000232796A JP 2000232796 A JP2000232796 A JP 2000232796A JP 3759383 B2 JP3759383 B2 JP 3759383B2
- Authority
- JP
- Japan
- Prior art keywords
- silver powder
- resin paste
- resin
- tap density
- conductive resin
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
- H01L24/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
- H01L24/26—Layer connectors, e.g. plate connectors, solder or adhesive layers; Manufacturing methods related thereto
- H01L24/28—Structure, shape, material or disposition of the layer connectors prior to the connecting process
- H01L24/29—Structure, shape, material or disposition of the layer connectors prior to the connecting process of an individual layer connector
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/013—Alloys
- H01L2924/0132—Binary Alloys
- H01L2924/01322—Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/10—Details of semiconductor or other solid state devices to be connected
- H01L2924/102—Material of the semiconductor or solid state bodies
- H01L2924/1025—Semiconducting materials
- H01L2924/10251—Elemental semiconductors, i.e. Group IV
- H01L2924/10253—Silicon [Si]
Landscapes
- Engineering & Computer Science (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Die Bonding (AREA)
- Conductive Materials (AREA)
Abstract
Description
【０００１】
【発明が属する技術分野】
本発明はＩＣ、ＬＳＩ等の半導体素子を金属フレームなどの基板に接着させる導電性樹脂ペースト及び半導体装置に関するものである。
【０００２】
【従来の技術】
半導体装置の組立における半導体素子を金属フレームに接着させる工程、いわゆるダイボンディング工程において用いられる半導体素子とリードフレームの接合方式は、金−シリコン共晶に始まり、半田、導電性樹脂ペーストと推移してきた。現在では、主にＩＣ、ＬＳＩの組立においては導電性樹脂ペーストを、トランジスタ、ダイオードなどのディスクリートにおいては半田を使用している。ＩＣ、ＬＳＩ等の半導体装置においては、半導体素子の面積が大きいことから半田に比べてより低応力性が高い導電性樹脂ペーストを使用する方法が主に用いられている。この導電性樹脂ペーストはエポキシ樹脂中に鱗片状銀粉が分散されており、導電性を有している導電性樹脂ペーストとして使われてきた。しかし近年の半導体装置において半導体素子と金属フレームの間の導電性に対する要求は少なくなってきており、銀粉を使用しないでシリカなどを使用した絶縁性の樹脂ペーストも使用されてきている。なぜならば近年の半導体装置では半導体素子や半導体装置のデザインの進歩に伴い、アースを取るために半導体素子の裏面から金属フレームに電気を流す構造が必ずしも必要とされていないためである。又導電性樹脂ペーストを通して導通させるＩＣにおいても電流が２〜３ｍＡ程度の微弱な電流である。この程度の電流では従来の導電性樹脂ペーストでも充分に対応が可能である。
【０００３】
一方半田を主に使用しているダイオード、トランジスタ等のディスクリートではその製品の構造上、半導体素子と金属フレームの間に導通する必要がある。しかも流れる電流はＩＣに比べ非常に高く数Ａ以上の製品もあるため、通電時に熱を生じるために、放熱板を取り付けて半導体素子の熱を逃がすことから樹脂ペーストに熱伝導性が要求される場合が多い。半田は導電性樹脂ペーストに比べ、導電性、熱伝導性に優れるためにディスクリートの分野で使用されてきた。
【０００４】
ところが近年の環境問題から各半導体メーカーは半田に使用している鉛を使わない方向に動いており、更に半田を使用する際には必要なフラックスの洗浄工程の削減や半田による接合では必要な半導体素子裏面の金、ニッケル等の金属蒸着を施す必要もないためディスクリートの分野においてもＩＣ、ＬＳＩに使用している導電性樹脂ペーストを使用しようとする動きがある。この状況において電気的な接合に関しては金属皮膜を施したフィラー（例えばポリマー、カーボン、シリカ、ガラスビーズ、その他の無機フィラー）を配合することにより、大電流が流れる半導体装置においても満足な導電性を得ることは可能であった。しかし大電流を流す半導体装置又はＩＣ分野でもＣＰＵやグラフィックプロセッサーなど高速作動する半導体装置や携帯電子機器などの高周波作動半導体装置では半導体素子から発生した熱により、ダイアタッチ層（接着層）の温度が高くなり、熱による抵抗が大きくなり、半導体装置としての性能を低下させるという結果が報告されている。従ってこの様な導電性には優れるが、熱放散性に劣る導電性樹脂ペーストを使用する場合には、充分な冷却機構を有する半導体装置でなければならなかったが、コストアップにつながり実用的ではなかった。
【０００５】
導電性樹脂ペーストの熱伝導性を向上させる手法として、熱伝導性の高い物質の使用や配合する物質の充填量の増加などがある。しかし充填材になり得る物質としてダイアモンド、グラファイトなど熱伝導性の非常に高いものはあるが、これらは非常に高価であり、形状も塊状、結晶状のもので導電性樹脂ペーストに必要な高いチキソ性を有するものにはならないという欠点があった。 一方、従来から導電性樹脂ペーストに使用されている銀粉は、金属の中でも最も熱伝導性に優れた金属のひとつであり、化学的安定性、加工性、価格など非常にバランスのよい物質であり、導電性樹脂ペーストの充填材として銀粉は最適であり、導電性樹脂ペーストの熱伝導性を向上させるためには充填材である銀粉の充填量をいかにして高充填化し熱伝導性を向上させるかが課題であった。
【０００６】
【発明が解決しようとする課題】
本発明は導電性に優れ、更に熱放散性にも優れる導電性樹脂ペースト及びこれを用いた半導体装置を提供するものである。
【０００７】
【課題を解決するための手段】
本発明は、（Ａ）常温で液状である熱硬化性樹脂、（Ｂ）ＴＡＰ密度が４．２ｇ／ｃｍ3以上の鱗片状銀粉を含む鱗片状銀粉を必須成分とする樹脂ペーストであって、全樹脂ペースト中のＴＡＰ密度４．２ｇ／ｃｍ3以上の鱗片状銀粉の含有量が３０重量％以上で、かつ全鱗片状銀粉の含有量が８０〜９４重量％であり、球状銀粉を含有しないことを特徴とする導電性樹脂ペースト及び該導電性樹脂ペーストを用いて製造されてなることを特徴とする半導体装置である。
【０００８】
【発明の実施の形態】
本発明に用いる銀粉は、ＴＡＰ密度が４．２ｇ／ｃｍ3以上の鱗片状銀粉を含んだ鱗片状銀粉を必須とし、全導電性樹脂ペースト中に含まれるＴＡＰ密度４．２ｇ／ｃｍ3以上の鱗片状銀粉の含有量は３０重量％以上で、かつ全鱗片状銀粉の含有量が８０〜９４重量％となり、球状銀粉を含有しないものである。本発明者らは、銀粉の高充填化は導電性樹脂ペース（以下、樹脂ペーストという）の粘度の増加を招き、塗布作業性が悪化するため樹脂ペーストの粘度を低くしなければならないので、高充填化できる最適な銀粉を得るため、ＴＡＰ密度、見かけ密度、平均粒径、最大粒径、比表面積などの銀粉の特性と樹脂ペーストの粘度との関係について種々検討した結果、充填性に優れた、つまりより多く充填しても樹脂ペーストの粘度を低くするにはＴＡＰ密度が高い銀粉を用いることが良いという知見を見出した。
【０００９】
一般的に樹脂ペーストには、主に鱗片状銀粉が用いられている。鱗片状銀粉のＴＡＰ密度は３．０〜３．８ｇ／ｃｍ3のものが主流である。これはより少ない銀粉量で電気を効率的に流すためにはＴＡＰ密度が小さい、つまり嵩が大きい銀粉を使用する方が有利だからである。しかし、この様なＴＡＰ密度が低い銀粉は樹脂ペーストの粘度が高くなり易く、より多くの銀粉を樹脂ペースト中に充填することは非常に困難であることから、熱伝導性の向上は期待できない。一方ＴＡＰ密度が大きく、高充填化が可能な銀粉としては球状銀粉があるが、球状銀粉を使用すると樹脂ペーストのチキソ性が低くなり、塗布作業中に樹脂ペーストのたれや糸引きなどが発生してしまう。そのため球状銀粉の使用はあまり好ましくない。従って熱伝導性が良好な樹脂ペーストには、ＴＡＰ密度が大きく、高充填化が可能な鱗片状銀粉の使用が望ましい。本発明で言う球状とは、平均的な粒径を有する銀粒子の断面を見て、縦横の比率、即ちアスペクト比が１．５以下のものを指し、又鱗片状銀粉とはアスペクト比が２．０以上を指す。
【００１０】
銀粉を高充填化するために、ＴＡＰ密度が４．２ｇ／ｃｍ3以上の鱗片状銀粉が好ましく、鱗片状銀粉のＴＡＰ密度が、４．２ｇ／ｃｍ3未満だと、いわゆる嵩が大きく、充填量を増やすと著しい塗布作業性の低下を生じ好ましくない。ＴＡＰ密度が４．２ｇ／ｃｍ3以上だと高充填化することができ、より高い熱伝導性を得ることができるので好ましい。
本発明で言うＴＡＰ密度とは、１００ｍｌのメスシリンダーに５０ｇの銀粉を入れ、３０００回タッピングした後の容積から求めたものである。
本発明で用いる鱗片状銀粉は基本的に還元法、電解法、アトマイズド法、粉砕法等で得られた原料銀粉をジェットミル、ロールミル、ボールミルなどで機械的に粉砕して得ることができる。銀粉のＴＡＰ密度は粒子形状と粒度分布によりほぼ決まるが、これらを決定するのはこの一連の工程の中で原料銀粉の粒径、粉砕条件を制御することによりＴＡＰ密度を高くしたり、低くしたりして、目的の鱗片状銀粉を得ることができる。
【００１１】
本発明では、ＴＡＰ密度が４．２ｇ／ｃｍ3以上の鱗片状銀粉を全樹脂ペースト中３０重量％以上含み、かつ全鱗片状銀粉含有量が８０〜９４重量％のものが望ましい。樹脂ペースト中の鱗片状銀粉が３０重量％未満だと高充填化が難しくなり好ましくない。更に全鱗片状銀粉含有量が樹脂ペースト中８０重量％未満だと充分な熱伝導性を得ることはできず、一方９４重量％を越えると熱伝導性には優れるもののＴＡＰ密度を高くしても粘度が高くなり過ぎ、塗布作業性が著しく低下するので好ましくない。
ＴＡＰ密度が４．２ｇ／ｃｍ3以上の鱗片状銀粉と併用する場合の銀粉としては、ＴＡＰ密度が４．２ｇ／ｃｍ3未満の鱗片状銀粉がある。ＴＡＰ密度が４．２ｇ／ｃｍ3以上の鱗片状銀粉を始め、本発明で用いる銀粉の最大粒径は３０μｍ以下が望ましい。３０μμｍを越えると塗布時にニードル詰まりをおこし、塗布作業性が著しく低下するため好ましくない。
【００１２】
本発明に用いる常温で液状である熱硬化性樹脂としては、特に限定しないが、例えばエポキシ樹脂、アクリレート樹脂、シアネート樹脂、ポリイミド樹脂、ビスマレイミド樹脂、フェノール樹脂、シリコーン樹脂などが挙げられる。これらの樹脂は、単独でも混合して用いてもよい。これらの熱硬化性樹脂の内で硬化剤を必要とするものについては、所望の特性に適合したものを適宜選択すればよい。
本発明の樹脂ペーストを用いて製造される半導体装置は、その製造工程内に半導体素子とリードフレームを金線で繋ぐワイヤーボンディングと言う工程があり、この工程において１５０〜２５０℃の温度がかかるため、熱可塑性樹脂を用いた場合、この温度では軟化してしまい、半導体素子が外れてしまう恐れがあるため、熱硬化性樹脂が好ましく、硬化方法、硬化温度等の用途により使い分ければよい。
常温で液状である熱硬化性樹脂を用いるのは、液状成分の中に銀粉を高充填化し満足できる熱伝導性を得るためである。常温で液状である熱硬化性樹脂を使用しなければ、満足できる熱伝導性が得られる銀粉の充填量を実現することはできない。又常温で固形の樹脂は、そのままでは銀粉を配合することができないために有機溶剤を使用する必要があり、この有機溶剤は揮発性が高いことから硬化時に急激に揮発し、ボイドが発生し樹脂ペーストの硬化物の熱伝導性を低下させるため、固形の熱硬化性樹脂は望ましくない。但し固形の熱硬化性樹脂でも有機溶剤に容易に溶解し、塗布作業性に影響のない粘度であれば、常温で液状の熱硬化性樹脂と併用してもよい。
【００１３】
本発明の樹脂ペーストには必要に応じて、硬化剤、硬化促進剤、顔料、消泡剤などの添加剤を用いることができる。本発明の製造方法は、例えば各成分を予備混練した後、三本ロールを用いて混練し、樹脂ペーストを得て真空下脱泡することなどがある。
本発明の樹脂ペーストを用いて製造された半導体装置は、信頼性が高い半導体装置である。半導体装置の製造方法は従来の公知の方法を用いることができる。
【００１４】
【実施例】
以下に本発明を実施例で具体的に説明する。
実施例１〜１１
・エポキシ樹脂Ａ（ビスフェノールＦ型エポキシ樹脂（常温で液状）／ｔ−ブチルフェニルグリシジルエーテル（常温で液状）／フェノールノボラック樹脂／１，８―ジアザビシクロ（５，４，０）ウンデセン―７（以下、ＤＢＵという）＝１００／９０／３０／０．２（重量部））
・エポキシ樹脂Ｂ（芳香族アミン型液状エポキシ樹脂（常温で液状）／ｔ−ブチルフェニルグリシジルエーテル（常温で液状）／フェノールノボラック樹脂／ＤＢＵ＝１００／９０／３０／０．２（重量部））
・エポキシ樹脂Ｃ（軟化点８０℃の固形オルソクレゾールノボラック型エポキシ樹脂／ｔ−ブチルフェニルグリシジルエーテル（常温で液状）／フェノールノボラック樹脂／ＤＢＵ＝１００／９０／３０／０．２（重量部））
・アクリレート樹脂（ポリブタジエン（常温で液状）／ラウリル酸アクリルエステル／過酸化物＝１００／７０／３（重量部））
・シアネート樹脂（テトラメチルビスフェノールＦ型シアネートエステル（常温で液状）／ノニルフェノール／コバルト−アセトキシアセトネート＝１００／２／２（重量部））
・シリコーン樹脂(ビニル型シリコーン樹脂（常温で液状）／白金触媒＝１００／０．５（重量部）)と
・銀粉Ｄ（鱗片状、ＴＡＰ密度＝４．４ｇ／ｃｍ3）
・銀粉Ｅ（鱗片状、ＴＡＰ密度＝５．２ｇ／ｃｍ3）
・銀粉Ｆ（鱗片状、ＴＡＰ密度＝５．６ｇ／ｃｍ3）
・銀粉Ｇ（鱗片状、ＴＡＰ密度＝３．６ｇ／ｃｍ3）
を表１に示す重量割合で配合し、３本ロールで混練して樹脂ペーストを得た。この樹脂ペーストを真空チャンバーにて２ｍｍＨｇで３０分脱泡後、以下に示す方法により各種性能を評価した。評価結果を表１に示す。
【００１５】
評価方法
・粘度：Ｅ型粘度計（３°コーン）を用い、２５℃、２．５ｒｐｍでの測定値。
・３日後粘度：２５℃恒温糟に３日放置した後、Ｅ型粘度計を用い、２５℃、２．５ｒｐｍでの測定値。
・チキソ比：Ｅ型粘度計を用い、２５℃での０．５ｒｐｍの測定値と２．５ｒｐｍの測定値の比率。
・体積抵抗率：スライドガラス上に樹脂ペーストを幅４ｍｍ、厚み３０μｍに塗布し１５０℃オーブン中で６０分間硬化した後の硬化物の体積抵抗率を測定した。
・２５０℃熱時接着強度：２ｍｍ角のシリコンチップを樹脂ペーストを用いて銀メッキした銅フレームにマウントし１５０℃のオーブン中で６０分間硬化した。硬化後、プッシュプルゲージを用い２５０℃での熱時ダイシェア強度を測定した。
・ボイド：樹脂ペーストを用いて、６ｘ６ｍｍのガラスチップを金属フレームにマウントし硬化後、目視で確認した。
・熱伝導率：直径２〜３ｃｍ、厚み１〜２ｃｍの円盤状硬化物試料を作製し、レーザーフラッシュ法により熱拡散係数を求めて、更に比熱、密度から熱伝導率を算出した。
・糸引き性：自動ディスペンサーで塗布した時のペーストの糸引き具合を目視で観察した。
・たれ性：糸引き性評価の際に塗布を中断して、そのまま放置して３０分後にノズルから樹脂ペーストがたれたか目視で確認した。
・総合評価：粘度、チキソ比、体積抵抗率、接着強度、ボイド、熱伝導率、糸引き性及びたれ性の全てが良好なものを○、１つでも不満足なものを×とした。
【００１６】
比較例１〜９
比較例１〜６は、実施例と同様にして、表２に示す配合割合で樹脂ペーストを作製した。
比較例１；銀粉の充填量が８０重量％未満の場合、粘度が低く、又導電性がよくない。
比較例２；銀粉の充填量が９２重量％を越えた場合、粘度が高く、糸引き性が悪化する。
比較例３；TAP密度が３．６ｇ／ｃｍ3の鱗片状銀粉である銀粉Ｇを使用した場合、８０重量％の充填量でも粘度が高くなり、糸引き性が充分ではない。
比較例４、５；銀粉Ｈ（球状、ＴＡＰ密度＝５．８ｇ／ｃｍ3）を使用するとチキソ性が低く、ペーストのたれが発生した。
比較例６；銀粉Ｄの充填量が３０重量％未満だと粘度が高くなり、糸引き性が悪化した。
比較例７、８；熱硬化性樹脂に代え、熱可塑性樹脂を溶解する有機溶剤に溶解し、それと銀粉を３本ロールを使用して作製した。この場合、熱時の接着強度が著しく低下した。
比較例９； 有機溶剤を配合した場合、硬化後に著しいボイドの発生が確認され熱伝導性が低下した。
【００１７】
【表１】
【表２】
【発明の効果】
本発明の導電性樹脂ペーストは作業性に優れ、これを用いた半導体装置は導電性及び熱放散性に優れており、半田代替が可能である。[0001]
[Technical field to which the invention belongs]
The present invention relates to a conductive resin paste for bonding a semiconductor element such as an IC or LSI to a substrate such as a metal frame and a semiconductor device.
[0002]
[Prior art]
The bonding method of a semiconductor element and a lead frame used in a process for bonding a semiconductor element to a metal frame in assembly of a semiconductor device, that is, a so-called die bonding process, has started from gold-silicon eutectic, and has changed from solder to conductive resin paste. . At present, conductive resin paste is mainly used in the assembly of ICs and LSIs, and solder is used in discretes such as transistors and diodes. In a semiconductor device such as an IC or LSI, a method of using a conductive resin paste having a higher low stress than solder is mainly used because the area of the semiconductor element is large. This conductive resin paste has a scaly silver powder dispersed in an epoxy resin, and has been used as a conductive resin paste having conductivity. However, in recent semiconductor devices, the demand for electrical conductivity between a semiconductor element and a metal frame has been reduced, and an insulating resin paste using silica or the like without using silver powder has been used. This is because, in recent semiconductor devices, with the progress of the design of semiconductor elements and semiconductor devices, a structure that allows electricity to flow from the back surface of the semiconductor elements to the metal frame is not necessarily required for grounding. Further, even in an IC conducted through a conductive resin paste, the current is a weak current of about 2 to 3 mA. With such a current level, a conventional conductive resin paste can be sufficiently handled.
[0003]
On the other hand, in discrete devices such as diodes and transistors mainly using solder, it is necessary to conduct between the semiconductor element and the metal frame because of the structure of the product. Moreover, since the current that flows is very high compared to ICs and there are products of several A or more, in order to generate heat when energized, a heat sink is attached to release the heat of the semiconductor element, so the resin paste is required to have thermal conductivity. There are many cases. Solder has been used in the field of discrete because of its superior conductivity and thermal conductivity compared to conductive resin paste.
[0004]
However, due to environmental problems in recent years, each semiconductor manufacturer is moving in a direction not to use the lead used in soldering. Further, when using solder, it is necessary to reduce the number of flux cleaning processes required for soldering and to join by soldering. Since there is no need to deposit metal such as gold and nickel on the back of the device, there is a movement to use conductive resin pastes used in ICs and LSIs in the field of discrete devices. In this situation, for electrical bonding, fillers with a metal film (for example, polymer, carbon, silica, glass beads, and other inorganic fillers) are blended to provide satisfactory conductivity even in semiconductor devices where large current flows. It was possible to get. However, even in the semiconductor device or IC field where a large current flows, the temperature of the die attach layer (adhesive layer) is increased by heat generated from the semiconductor element in a semiconductor device that operates at high speed such as a CPU or graphic processor or a high-frequency operation semiconductor device such as a portable electronic device. It has been reported that the temperature is increased, the resistance due to heat is increased, and the performance as a semiconductor device is degraded. Therefore, when using a conductive resin paste that is excellent in such conductivity but inferior in heat dissipation, it has to be a semiconductor device having a sufficient cooling mechanism. There wasn't.
[0005]
As a method for improving the thermal conductivity of the conductive resin paste, there are the use of a substance having high thermal conductivity and an increase in the filling amount of the substance to be blended. However, there are some materials that can be used as fillers, such as diamond and graphite, which have very high thermal conductivity, but they are very expensive and have a massive or crystalline shape, which is necessary for conductive resin pastes. There is a drawback that it does not have a property. On the other hand, silver powder that has been used in conductive resin pastes is one of the metals with the highest thermal conductivity among metals, and it is a very well balanced substance such as chemical stability, processability, and price. Silver powder is optimal as a filler for conductive resin paste, and in order to improve the thermal conductivity of conductive resin paste, how to increase the filling amount of silver powder as a filler to improve thermal conductivity It was a problem.
[0006]
[Problems to be solved by the invention]
The present invention provides a conductive resin paste excellent in conductivity and further excellent in heat dissipation and a semiconductor device using the same.
[0007]
[Means for Solving the Problems]
The present invention is a resin paste comprising, as an essential component, (A) a thermosetting resin that is liquid at room temperature, and (B) a flaky silver powder containing a flaky silver powder having a TAP density of 4.2 g / cm 3 or more, in the content of the TAP density of 4.2 g / cm 3 or more flake silver powder in the total resin paste 30 wt% or more and Ri content of 80 to 94 wt% der of the total flake silver powder, containing spherical silver powder A conductive resin paste characterized by not being manufactured, and a semiconductor device manufactured using the conductive resin paste.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Silver powder used in the present invention, TAP density is essential flaky silver powder containing 4.2 g / cm 3 or more flake silver powder, TAP density 4.2 g / cm 3 or more contained in the entire conductive resin paste the content of scaly silver powder is 30 wt% or more and the total content of flake silver powder Ri do a 80 to 94% by weight, but containing no spherical silver powder. The present inventors have increased the filling of silver powder, which increases the viscosity of the conductive resin pace (hereinafter referred to as resin paste), and the workability of coating deteriorates, so the viscosity of the resin paste must be lowered. As a result of various investigations on the relationship between the properties of silver powder such as TAP density, apparent density, average particle diameter, maximum particle diameter, specific surface area, and viscosity of resin paste, in order to obtain an optimal silver powder that can be filled, it was excellent in fillability. That is, the present inventors have found that it is preferable to use silver powder having a high TAP density in order to reduce the viscosity of the resin paste even when the amount is more filled.
[0009]
Generally, scaly silver powder is mainly used for resin paste. The TAP density of the scaly silver powder is mainly 3.0 to 3.8 g / cm 3 . This is because it is more advantageous to use a silver powder having a small TAP density, that is, a bulk, in order to allow electricity to flow efficiently with a smaller amount of silver powder. However, such a silver powder having a low TAP density tends to increase the viscosity of the resin paste, and it is very difficult to fill a larger amount of the silver powder into the resin paste, so that improvement in thermal conductivity cannot be expected. On the other hand, there is a spherical silver powder as a silver powder that has a high TAP density and can be highly filled. However, if the spherical silver powder is used, the thixotropy of the resin paste is lowered, and the resin paste sagging or stringing occurs during the coating operation. End up. Therefore, the use of spherical silver powder is not so preferable. Therefore, it is desirable to use scale-like silver powder that has a high TAP density and can be highly filled for a resin paste having good thermal conductivity. The spherical shape referred to in the present invention refers to the aspect ratio of the silver particles having an average particle diameter, that is, the aspect ratio is 1.5 or less, and the scale-like silver powder has an aspect ratio of 2 0 or higher.
[0010]
In order to make the silver powder highly filled, a flaky silver powder having a TAP density of 4.2 g / cm 3 or more is preferable. If the TAP density of the flaky silver powder is less than 4.2 g / cm 3 , the so-called bulk is large, and the filling is performed. Increasing the amount is not preferable because it causes a significant decrease in coating workability. When the TAP density is 4.2 g / cm 3 or more, high filling can be achieved, and higher thermal conductivity can be obtained, which is preferable.
The TAP density referred to in the present invention is determined from the volume after putting 50 g of silver powder into a 100 ml measuring cylinder and tapping 3000 times.
The scaly silver powder used in the present invention can be basically obtained by mechanically pulverizing raw material silver powder obtained by a reduction method, electrolysis method, atomized method, pulverization method or the like with a jet mill, a roll mill, a ball mill or the like. The TAP density of silver powder is almost determined by the particle shape and particle size distribution, but these are determined by increasing or decreasing the TAP density by controlling the particle size and grinding conditions of the raw silver powder in this series of steps. As a result, the target scaly silver powder can be obtained.
[0011]
In the present invention, it is desirable that the flaky silver powder having a TAP density of 4.2 g / cm 3 or more is 30% by weight or more in the total resin paste and the total flaky silver powder content is 80 to 94% by weight. When the scale-like silver powder in the resin paste is less than 30% by weight, it is difficult to achieve high filling, which is not preferable. Furthermore, if the total flaky silver powder content is less than 80% by weight in the resin paste, sufficient thermal conductivity cannot be obtained. On the other hand, if it exceeds 94% by weight, the thermal conductivity is excellent but the TAP density is increased. This is not preferable because the viscosity becomes too high and the coating workability is remarkably lowered.
The silver powder when the TAP density is combined with 4.2 g / cm 3 or more flake silver powder, TAP density is flaky silver powder of less than 4.2 g / cm 3. The maximum particle size of the silver powder used in the present invention including the flaky silver powder having a TAP density of 4.2 g / cm 3 or more is desirably 30 μm or less. If it exceeds 30 μm, needle clogging occurs at the time of coating, and the coating workability is remarkably deteriorated.
[0012]
Although it does not specifically limit as a thermosetting resin which is liquid at normal temperature used for this invention, For example, an epoxy resin, an acrylate resin, cyanate resin, a polyimide resin, a bismaleimide resin, a phenol resin, a silicone resin etc. are mentioned. These resins may be used alone or in combination. Among these thermosetting resins, those that require a curing agent may be appropriately selected to meet the desired characteristics.
The semiconductor device manufactured using the resin paste of the present invention has a process called wire bonding in which the semiconductor element and the lead frame are connected by a gold wire in the manufacturing process, and a temperature of 150 to 250 ° C. is applied in this process. When a thermoplastic resin is used, it is softened at this temperature and the semiconductor element may be detached. Therefore, a thermosetting resin is preferable, and it may be properly used depending on applications such as a curing method and a curing temperature.
The reason why the thermosetting resin that is liquid at normal temperature is used is to obtain a satisfactory thermal conductivity by highly filling silver powder into the liquid component. Unless a thermosetting resin that is liquid at room temperature is used, it is not possible to achieve a silver powder filling amount that provides satisfactory thermal conductivity. In addition, since a solid resin at room temperature cannot be mixed with silver powder as it is, it is necessary to use an organic solvent. Since this organic solvent has high volatility, it rapidly volatilizes during curing and voids are generated. Solid thermosetting resins are undesirable because they reduce the thermal conductivity of the cured paste. However, even a solid thermosetting resin can be used in combination with a thermosetting resin that is liquid at room temperature as long as it is easily dissolved in an organic solvent and does not affect the workability of coating.
[0013]
In the resin paste of the present invention, additives such as a curing agent, a curing accelerator, a pigment, and an antifoaming agent can be used as necessary. In the production method of the present invention, for example, each component is pre-kneaded and then kneaded using a three roll to obtain a resin paste and defoamed under vacuum.
A semiconductor device manufactured using the resin paste of the present invention is a highly reliable semiconductor device. As a method for manufacturing the semiconductor device, a conventionally known method can be used.
[0014]
【Example】
The present invention will be specifically described below with reference to examples.
Examples 1-11
Epoxy resin A (bisphenol F type epoxy resin (liquid at normal temperature) / t-butylphenyl glycidyl ether (liquid at normal temperature) / phenol novolac resin / 1,8-diazabicyclo (5,4,0) undecene-7 (hereinafter DBU) = 100/90/30 / 0.2 (parts by weight))
Epoxy resin B (aromatic amine type liquid epoxy resin (liquid at normal temperature) / t-butylphenyl glycidyl ether (liquid at normal temperature) / phenol novolac resin / DBU = 100/90/30 / 0.2 (parts by weight))
Epoxy resin C (solid orthocresol novolak type epoxy resin having a softening point of 80 ° C./t-butylphenylglycidyl ether (liquid at normal temperature) / phenol novolak resin / DBU = 100/90/30 / 0.2 (parts by weight))
Acrylate resin (polybutadiene (liquid at room temperature) / lauric acid acrylic ester / peroxide = 100/70/3 (parts by weight))
Cyanate resin (tetramethylbisphenol F type cyanate ester (liquid at normal temperature) / nonylphenol / cobalt-acetoxyacetonate = 100/2/2 (parts by weight))
・ Silicone resin (vinyl type silicone resin (liquid at normal temperature) / platinum catalyst = 100 / 0.5 (parts by weight)) and silver powder D (flaky, TAP density = 4.4 g / cm 3 )
Silver powder E (scale-like, TAP density = 5.2 g / cm 3 )
Silver powder F (scale-like, TAP density = 5.6 g / cm 3 )
Silver powder G (scale-like, TAP density = 3.6 g / cm 3 )
Were mixed at a weight ratio shown in Table 1, and kneaded with three rolls to obtain a resin paste. The resin paste was defoamed at 2 mmHg for 30 minutes in a vacuum chamber, and then various performances were evaluated by the following methods. The evaluation results are shown in Table 1.
[0015]
Evaluation method Viscosity: Measured value at 25 ° C. and 2.5 rpm using an E-type viscometer (3 ° cone).
Viscosity after 3 days: measured at 25 ° C. and 2.5 rpm using an E-type viscometer after standing in a constant temperature bath at 25 ° C. for 3 days.
Thixo ratio: A ratio of a measured value of 0.5 rpm and a measured value of 2.5 rpm at 25 ° C. using an E-type viscometer.
Volume resistivity: The volume resistivity of the cured product after applying a resin paste on a slide glass to a width of 4 mm and a thickness of 30 μm and curing in a 150 ° C. oven for 60 minutes was measured.
-Adhesive strength when heated at 250 ° C .: A 2 mm square silicon chip was mounted on a silver-plated copper frame using a resin paste and cured in an oven at 150 ° C. for 60 minutes. After curing, the hot die shear strength at 250 ° C. was measured using a push-pull gauge.
-Void: Using a resin paste, a 6 x 6 mm glass chip was mounted on a metal frame, cured, and visually confirmed.
-Thermal conductivity: A disk-shaped cured material sample having a diameter of 2 to 3 cm and a thickness of 1 to 2 cm was prepared, the thermal diffusion coefficient was determined by a laser flash method, and the thermal conductivity was further calculated from the specific heat and density.
-Stringing property: The condition of stringing of the paste when applied with an automatic dispenser was visually observed.
-Sagging property: The coating was interrupted during the evaluation of the stringiness, and left as it was, and after 30 minutes, it was visually confirmed whether the resin paste was dripped from the nozzle.
-Comprehensive evaluation: The case where all of the viscosity, the thixo ratio, the volume resistivity, the adhesive strength, the void, the thermal conductivity, the stringing property and the sagging property were good was evaluated as ◯, and even one which was unsatisfactory was evaluated as ×.
[0016]
Comparative Examples 1-9
In Comparative Examples 1 to 6, resin pastes were prepared at the blending ratios shown in Table 2 in the same manner as in the Examples.
Comparative Example 1: When the filling amount of silver powder is less than 80% by weight, the viscosity is low and the conductivity is not good.
Comparative Example 2: When the filling amount of silver powder exceeds 92% by weight, the viscosity is high and the stringiness is deteriorated.
Comparative Example 3 When silver powder G, which is a scaly silver powder having a TAP density of 3.6 g / cm 3 , is used, the viscosity becomes high even with a filling amount of 80% by weight, and the stringiness is not sufficient.
Comparative Examples 4 and 5: When silver powder H (spherical, TAP density = 5.8 g / cm 3 ) was used, the thixotropy was low and paste dripping occurred.
Comparative Example 6: When the filling amount of the silver powder D was less than 30% by weight, the viscosity was increased and the stringiness was deteriorated.
Comparative Examples 7 and 8: In place of the thermosetting resin, the thermoplastic resin was dissolved in an organic solvent, and silver powder was prepared using three rolls. In this case, the adhesive strength during heating was significantly reduced.
Comparative Example 9: When an organic solvent was blended, significant voids were confirmed after curing and the thermal conductivity was lowered.
[0017]
[Table 1]
[Table 2]
【The invention's effect】
The conductive resin paste of the present invention is excellent in workability, and a semiconductor device using the conductive resin paste is excellent in conductivity and heat dissipation, and can be replaced with solder.
Claims (2)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000232796A JP3759383B2 (en) | 2000-08-01 | 2000-08-01 | Conductive resin paste and semiconductor device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000232796A JP3759383B2 (en) | 2000-08-01 | 2000-08-01 | Conductive resin paste and semiconductor device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2002050227A JP2002050227A (en) | 2002-02-15 |
| JP3759383B2 true JP3759383B2 (en) | 2006-03-22 |
Family
ID=18725418
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2000232796A Expired - Lifetime JP3759383B2 (en) | 2000-08-01 | 2000-08-01 | Conductive resin paste and semiconductor device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3759383B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4946130B2 (en) * | 2006-03-28 | 2012-06-06 | 住友ベークライト株式会社 | Conductive paste and semiconductor device manufactured using conductive paste |
| JP6062974B2 (en) | 2014-02-24 | 2017-01-18 | 三ツ星ベルト株式会社 | Conductive composition |
-
2000
- 2000-08-01 JP JP2000232796A patent/JP3759383B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JP2002050227A (en) | 2002-02-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP7032398B2 (en) | Thermally Conductive Conductive Adhesive Composition | |
| JP3837858B2 (en) | Conductive adhesive and method of using the same | |
| JP4507488B2 (en) | Bonding material | |
| JP2007149522A (en) | Conductive resin paste composition containing silver and carbon nanotube, and semiconductor device using this | |
| JP3747995B2 (en) | Conductive resin paste and semiconductor device using the same | |
| JP3254626B2 (en) | Conductive resin paste and semiconductor device using the same | |
| JP4174088B2 (en) | Conductive resin paste and semiconductor device manufactured using the same | |
| JP2006120665A (en) | Conductive resin paste composition containing silver and carbon nano tube, and semiconductor device using the same | |
| JP5157938B2 (en) | Resin paste for die bonding, semiconductor device manufacturing method using the resin paste, and semiconductor device obtained by the manufacturing method | |
| JPH07126489A (en) | Electrically conductive resin paste | |
| JP3759383B2 (en) | Conductive resin paste and semiconductor device | |
| JP3526183B2 (en) | Conductive resin paste and semiconductor device manufactured using the same | |
| JP2003138244A (en) | Resin paste for semiconductor and semiconductor device | |
| JP3469432B2 (en) | Conductive resin paste and semiconductor device manufactured using the same | |
| JP2003147279A (en) | Conductive adhesive and circuit board using the same for semiconductor, or the like | |
| JP3254625B2 (en) | Conductive resin paste and semiconductor device using the same | |
| CN112912192A (en) | Composition containing metal particles and conductive adhesive film | |
| JP2001226596A (en) | Electroconductive resin paste and semiconductor device manufactured therewith | |
| JP2002284889A (en) | Manufacturing method of resin paste for semiconductor, resin paste for semiconductor and semiconductor device | |
| JP2006302834A (en) | Die bonding paste | |
| JP2006073811A (en) | Die bonding paste | |
| JPH10340624A (en) | Conductive resin paste and semiconductor device manufactured by using this | |
| JP3250793B2 (en) | Conductive resin paste and semiconductor device using the same | |
| JP3418515B2 (en) | Conductive resin paste and semiconductor device manufactured using the same | |
| JPH10121012A (en) | Conductive resin paste and semiconductor device prepared using the same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20030512 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20050831 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20050906 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20051107 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20051227 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20051228 |
|
| R150 | Certificate of patent or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 Ref document number: 3759383 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100113 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110113 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120113 Year of fee payment: 6 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120113 Year of fee payment: 6 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130113 Year of fee payment: 7 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130113 Year of fee payment: 7 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20140113 Year of fee payment: 8 |
|
| EXPY | Cancellation because of completion of term |