JP4243077B2 - Semiconductor device and manufacturing method thereof - Google Patents

Semiconductor device and manufacturing method thereof Download PDF

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Publication number
JP4243077B2
JP4243077B2 JP2002213249A JP2002213249A JP4243077B2 JP 4243077 B2 JP4243077 B2 JP 4243077B2 JP 2002213249 A JP2002213249 A JP 2002213249A JP 2002213249 A JP2002213249 A JP 2002213249A JP 4243077 B2 JP4243077 B2 JP 4243077B2
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substrate
semiconductor element
semiconductor
external terminal
adhesive
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JP2004055937A (en
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直敬 田中
賢哉 河野
英生 三浦
孝洋 内藤
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Renesas Technology Corp
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    • H01L2224/10Bump connectors; Manufacturing methods related thereto
    • H01L2224/15Structure, shape, material or disposition of the bump connectors after the connecting process
    • H01L2224/16Structure, shape, material or disposition of the bump connectors after the connecting process of an individual bump connector
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    • H01L2224/26Layer connectors, e.g. plate connectors, solder or adhesive layers; Manufacturing methods related thereto
    • H01L2224/31Structure, shape, material or disposition of the layer connectors after the connecting process
    • H01L2224/32Structure, shape, material or disposition of the layer connectors after the connecting process of an individual layer connector
    • H01L2224/321Disposition
    • H01L2224/32135Disposition the layer connector connecting between different semiconductor or solid-state bodies, i.e. chip-to-chip
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    • H01L2224/321Disposition
    • H01L2224/32151Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
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    • H01L2224/42Wire connectors; Manufacturing methods related thereto
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    • H01L2224/42Wire connectors; Manufacturing methods related thereto
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    • H01L2224/481Disposition
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    • H01L2224/48227Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being non-metallic, e.g. insulating substrate with or without metallisation connecting the wire to a bond pad of the item
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    • H01L2224/484Connecting portions
    • H01L2224/48463Connecting portions the connecting portion on the bonding area of the semiconductor or solid-state body being a ball bond
    • H01L2224/48465Connecting portions the connecting portion on the bonding area of the semiconductor or solid-state body being a ball bond the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
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Description

【0001】
【発明の属する技術分野】
本発明は半導体装置に関し、半導体素子と基板とを接着材を介して固定された半導体装置に関する。
【0002】
【従来の技術】
既存のLSI製品を先進の実装技術で高密度かつ狭ピッチに実装し高性能なシステムを実現するSiP(System in Package)技術1)が注目されている。LSIと基板を狭ピッチに実装(接続)する技術として,200〜300μm以上の接続ピッチに対しては従来から広く適用されているC4(Controlled Collapse Chip Connection) 2)によるはんだバンプ接合がある。一方,はんだでは実現が困難な200μmピッチ以下のバンプ接続技術として金バンプを用いたフリップチップ技術がある。この金バンプを用いた接合方法には,金/金接合3)や金/はんだ接合4)のようにメタラジカルな接合技術とACF(Anisotropic Conductive Film)やACP(Anisotropic Conductive Paste)等を用いた非メタラジカルな接合技術がある。この中で非メタラジカルな接合はバンプ/電極間の電気的導通と封止プロセスを一回の低温熱圧着で達成でき,かつ鉛フリーで接続可能であることから,狭ピッチ接続を低コストで実現できる環境対応実装技術として有力視されている。ACFを用いた実装構造は,液晶用のドライバーICをガラス基板上に接続する方法として採用されてきたが,近年,低コストで有機基板への狭ピッチ接続を可能にする技術として,盛んに適用が進められている。
【0003】
ACF等を用いた非メタラジカルな接合では,はんだ接続のように接合部が合金結合しているのではなく,金バンプと基板上の電極との接触によって電気的な導通を達成しているため,金属製のバンプ電極とそれらを封止した接着剤の熱膨張差の影響により保証温度範囲内で接触圧力が無くなってしまうと電気的に断線してしまうという問題がある。これに対して本接合形態を考慮した接合信頼性向上のための発明がいくつ開示されている。例えば特開平11−067832号公報では,ACF(異方性導電樹脂)を用いたフリップチップ接合において,例えばバンプ電極である金の線膨張係数よりもACF材のそれを同等かそれ以下にすることで,接続信頼性を向上させる製造方法を提供している。また,特開2001−308230号公報では,金バンプによるフリップチップ接合部分を封止する材料の線膨張係数よりも,LSIチップ領域を含む全体を封止する材料の線膨張係数を小さくすることで,フリップチップ接合部の接続信頼性を向上させる製造方法を提供している。
【0004】
【発明が解決しようとする課題】
これらの、構造では、金バンプによるフリップチップ接合部を封止した材料の熱収縮によってバンプ接触面に圧縮応力が生じ電気的な導通を達成しているため,高温試験等の環境試験において封止材料の熱膨張によってバンプの接触応力が減少するのを,周囲の低熱膨張な封止樹脂が抑え込むことによって接続信頼性を安定化させていると考えられる。
【0005】
上記特開平11−067832号公報で提供された発明では,一般的な金の線膨張係数は14ppm前後であるので,有機系の材料で上記と同等またはそれ以下の物性を達成できるバインダー材料となると,物性的に使用できるものが大幅に制限されてしまう。また,金バンプよりもACF材の線膨張係数が小さい場合,圧着硬化時に十分な圧縮応力がバンプの接触界面に発生せず,初期的な接合信頼性が十分に得られない場合がある。
【0006】
さらに,特開2001−308230号公報で提供された発明では,低熱膨張な樹脂で全体を封止することは,封止後の冷却時にも,フリップチップ領域の封止樹脂の熱収縮を抑制してしまうため,再度加熱昇温された場合の接続マージンを増加させる効果はあまり大きくない。
【0007】
上記の発明はいずれも温度サイクル試験や高温放置試験等の昇温加熱によってバンプ接触面の圧縮応力が減少するのを防止することに主眼がおかれた発明である。しかしながら,最近の有機基板へのフリップチップ接続の適用によって,LSIチップと線膨張係数差が大きい有機基板との接続においては,昇温加熱時だけでなく冷却過程においても接続信頼性の低下を生じる恐れがある。これは,両者の線膨張係数差によるバイメタル現象によって,冷却過程において反りが発生し,コーナ領域のバンプ電極で接触応力の減少が生じるためである。
【0008】
さらに,携帯電話をはじめとするモバイル機器への用途が非常に多くなっているため,従来の耐温度サイクル性や耐湿性だけでなく,筐体の変形や落下時の衝撃によって内蔵された搭載基板が外力によって変形し,基板に実装されたLSIの接続信頼性を悪化させることを防止することが望まれる。
【0009】
本発明の目的は,前記の課題を解決でき、外部端子と対応する基板との高信頼な電気的接続構造を備えた半導体装置を提供することにある。
【0010】
【課題を解決するための手段】
このように、本発明によれば,50〜60μm以下の狭ピッチなフリップチップ接続を低コストかつ高信頼に達成することが可能である。具体的には,バンプ電極の塑性変形を抑制できるため,温度サイクル試験に対して高寿命な設計が可能となり,携帯機器実装に伴う基板曲げ外力に対しても強く,接着界面を低応力化できるため,吸湿に伴うマイグレーションの発生も抑制する効果が高くなる。
【0011】
さらに将来的な実装構造の更なる薄型化やマルチチップ構造や三次元積層構造に対しても好適な高信頼接続を達成することが可能となる。
【0012】
本発明は、例えば、外部端子とその周囲に形成される接着材を介して積層された基板を備えた半導体装置に関して、前記基板表面から前記半導体素子の配線及び前記外部端子の形成される主面の反対側の主面までの厚さが前記外部端子の位置する領域の方がその周囲より厚くなるよう形成されている領域を有する。
【0013】
特に、前記第一の半導体素子の第一の前記外部端子が配置される領域は、前記基板表面から前記半導体素子の前記外部端子の位置する主面と反対側の主面までの厚さの最も大きい部分と小さい部分との差が20nm以上である。或いは前記差が100nm以下である。
【0014】
【発明の実施の形態】
本発明の実施形態を以下に説明する。なお、本発明は、以下に記載された形態に限られるのではなく、公知技術を用いて改良・修正することを妨げるものではない。
(1)一の実施の形態例として,半導体集積回路が形成されている半導体素子と、前記半導体素子が実装される配線基板と、前記半導体素子と前記配線基板が、前記半導体素子上に形成された複数の突起電極によって,前記配線基板に形成された複数の基板電極と電気的に接続されており、前記半導体素子と前記配線基板の隙間を充填するように形成された接着材からなる半導体装置において、前記突起電極によって電気的に接続されている領域あるいは位置における厚さ方向の総厚さが,前記突起電極位置における半導体素子あるいは配線基板の撓み変形によって,前記突起電極が形成されていない領域あるいは位置における厚さ方向の総厚さより厚くなるように形成されている。
【0015】
前記半導体素子と前記基板との間は前記外部端子の周囲の外部端子が設置されていない領域では接着剤によって固定されている。一方、前記外部端子と対応する基板とは、はんだ等のような導電性の固定部材を非設置として配置されている領域を有する。これは、実質的にははんだなどの固定部材が前記外部端子と対応する基板との間に設置されていないことを意味する。もっとも、これは、前記固定部材が実質的に非設置であると言う意味に過ぎず、製造工程上外部端子の周囲に充填される接着剤が前記外部端子と対応する前記基板との間に配置されることを許容するものである。前記半導体素子の前記外部端子が形成された主面或いは前記主面の反対側の主面であって、前記外部端子が位置する領域は、前記外部端子が位置する領域の周囲の領域よりも大きな曲率を有する。前記の周囲の領域として、前記外部端子の周囲であればよい。例えば、半導体素子の端部近傍に外部端子が配置されているタイプの素子の場合は、素子の一つの辺の端部近傍に設置された外部端子と、その対向する辺の端部に設置された外部端子との中央部における曲率を比較することができる。或いは、素子の中央部を通るように外部端子が配置されている場合は、外部端子と素子端部との中央部での曲率を比較することができる。
【0016】
例えば、具体的には、前記突起電極によって電気的に接続されている領域の直上直下の前記半導体素子裏面(バックグラインド面)あるいは搭載基板裏面に曲げ曲率が形成され,厚さ方向に撓んでいる。
(2)あるいは,半導体装置において、前記突起電極を支点として,前記接着材の熱収縮によって生じる曲げモーメント力によって,前記半導体素子あるいは前記配線基板に生じる曲げ曲率の厚さに対する変化率が顕著に大きくなるように,少なくとも前記半導体素子の厚さが0.1mm以下,あるいは有機系材料から構成される前記配線基板の厚さが0.2mm以下,あるいはその両者からなるよう形成されている。
(3)或いは、さらに,上記の半導体装置において,突起電極の基板電極への接続間隔が60μm以下である場合,突起電極と基板電極間の接合が金属結合ではなく,両電極の接触によって電気的導通が達成さている場合,突起電極周囲を充填している接着材の室温における線膨張係数は20ppm以上,50ppm以下の範囲にあり,基板電極直下の搭載基板材のガラス転移温度が100℃以上,250℃以下の範囲にのみある場合,配線基板の総厚と半導体素子の総厚およびその隙間を充填した接着材の総厚からなる3層積層構造において定義される曲げ変形に対する中立軸位置が,前記接着材の総厚領域にあって,例えば半導体素子がシリコンで,配線基板が有機系材料からなる場合,配線基板に対する半導体素子の厚さの比率を0.25〜0.35の範囲で構成されている。
【0017】
以下に作用効果のメカニズムについて説明する。図8は,厚いチップと厚い基板の組合わせの場合と,薄いチップと薄い基板の組合わせの場合において,本実装方法を適用した際の各構成部材の変形状態を概念的に示した図である。
【0018】
本実装形態における電気的な導通は,LSIチップ上に形成されたバンプ電極を,ACF等の異方性導電接着材あるいは非導電性の接着材を介して基板電極に熱圧着し,上記接着材の硬化収縮および圧着温度からの熱収縮によって,バンプ電極/基板電極間の接触面に接触圧力が生じることで達成される。
【0019】
したがって,チップ発熱に伴う温度変化や吸湿等による材料の経時変化に対して,接触面の接触圧力を設計的に安定化させることが,高信頼な接続を達成する上で非常に重要となる。昨今の接続ピッチに微細化に伴い,バンプ電極サイズも微細化が加速し,例えば80μmピッチ接続を達成するには,少なくとも直径が60μm以下のバンプサイズにする必要がある。バンプの微細化により,上記接着材の熱収縮に伴う接触面の圧縮応力が増大し,バンプの塑性変形を加速させやすくなっている。バンプ電極の塑性変形(永久変形)が大きくなると,再加熱された際に接触面の接触応力は急速に減少し,接続信頼性を悪化させる。
【0020】
図8に示すように厚いチップと厚い基板の組合わせでは,挟まれる両者の剛性が大きいために,接着材の熱収縮に伴う負荷はバンプ電極に集中し,図示のようにバンプの塑性変形(永久変形)を加速させる。これに対して薄チップと薄基板の組合わせでは,室温レベルでは、図示のように接着材の熱収縮に伴う変形をLSIチップまたは基板の変形で吸収できるので,適正な接触圧力を確保しながらも,バンプ電極の塑性変形を抑制することができる。
【0021】
さらに,接着材の熱収縮に伴って発生する接着界面の引張/せん断応力も減少するため,接着界面のはく離防止にも効果的である。LSIチップや基板電極は弾性変形の範囲内でバンプ電極接続部の上下両端方向に膨らむように変形するので,再加熱時にも変形は可逆的に作用し,バンプ電極接触面に作用する接触圧力の減少を抑制し,当初の設計目標であるバンプ接触面の接触圧力をより安定な方向へ改善することが可能である。
【0022】
図9はLSIチップおよび有機基板に単位曲げモーメントが生じた際に発生する曲げ曲率を材料力学のはり理論から算出した結果である。図中に示したように,曲げモーメントによって発生する曲率は,弾性係数と厚さの3乗に反比例する。図1に示したように,接着材の熱収縮によりバンプ電極を支点とした曲げモーメントがLSIチップに作用した際に,図示のような曲げ曲率r1が形成されるのは,少なくとのチップ厚さが0.3mm以下になった場合で,0.1mmより薄くなると曲げ曲率が急速に大きくなることがわかる。有機系基板の場合も少なくとも0.5mm以下になった場合で,0.2mmより薄くなると曲げ曲率が急速に大きくなることがわかる。すなわち,LSIチップを有機系配線基板に本実装形態で接続する際には,LSIチップを0.1mmより薄くする,あるいは基板厚さ(ガラスエポキシ有機系)を0.2mmより薄くした組合わせで実施すれば,先に示した図1のメカニズムよりバンプ電極の塑性変形を抑制しながら,LSIチップあるいは配線基板の弾性変形によって温度変化に対するバンプ電極接触面の接触力の維持が可能となり,高信頼な接続を達成することができる。厚さの下限は、製造プロセス上の観点やその他の観点で定めることができる。なお、一例としては、以下の観点で定めることができる。前記チップについては、圧着する際の強度を確保する観点から0.01mm以上であることが好ましい。前記基板に関しては、製造上の容易性の観点から0.05mm以上であることが好ましい。
【0023】
図10は,有機系基板に本実装方法を用いてLSIチップを実装した構造において,外力によって基板が変形を受けた際の各構成部材の変形状態を概念的に示したものである。図中には搭載したチップが厚い場合と薄い場合が示されている。外力によって搭載基板が図示のような変形を受けた場合,全体の反り変形によって曲げ曲率が大きくなり,LSIチップには平坦に戻ろうとする反力が作用してくる。
【0024】
したがってLSIチップが厚くて剛性が大きいと,接着材がその反力にうち負けてバンプ電極接触面の接触圧力が減少するが,LSIチップが薄くて剛性が小さければその減少を防止できる。
【0025】
さらに,基板変形に対して接続信頼性を向上させる方法としては,図中に示すように,バンプ電極/基板電極の接触接合エリアを含む接着材で充填された領域を,曲げ変形に対する厚さ方向の中立軸位置にすることが有効である。これにより,曲げや反り変形に対してLSIチップや搭載基板と接着材との接着界面やバンプ電極/基板電極接合部の変形が抑制されるため,より高信頼な接続構造を達成することができる。これは材料力学のはり理論から,各構成部材の弾性係数と厚さから簡便に定義することが可能である。例えば,LSIチップがシリコンで搭載基板が有機系材料(例えばガラスエポキシ)からなる場合,LSIチップの搭載基板に対する厚さの比率が0.3程度の場合に,両者の接合界面が中立軸位置となる。実際にはその中間領域にバンプ電極による接続界面を含む接着材領域が存在するので,先の厚さの比率が0.25〜0.35の範囲にあるようにLSIチップと搭載基板の厚さが設定されれば,外力等に対してバンプ電極界面の変形を抑制し,高信頼な接続構造を達成できる。
【0026】
温度サイクル試験等の冷却過程においても同様な現象が生じる場合がある。有機系基板の線膨張係数(一般に10〜20ppm)はLSIチップ(シリコン)の線膨張係数(3ppm程度)に比べて格段に小さいため,熱圧着温度からの冷却過程において,搭載基板に外力を受けた場合と同様な反り変形を生じる。したがって,LSIチップの剛性が大きい場合や,圧着温度からのΔTが大きい場合にはバンプ電極接触面の接触応力が減少し,接続信頼性を悪化させる可能性がある。
【0027】
図11は,上記の発生メカニズムを定量的に検証するために,有限要素法による構造解析を行い,バンプ電極接触面に作用する接触応力及び塑性ひずみ変化を算出した結果である。図中にはチップ厚さが0.4mmで基板厚さが1.0mmの組合わせで解析した場合(いずれも単位モーメント力に対して曲げ曲率を形成しない条件)と,チップ厚さが0.05mmで基板厚さが0.4mmの組合わせで解析した場合(チップ厚さが単位モーメント力に対して大きな曲げ曲率を形成できる条件)がそれぞれ示されている。
【0028】
これにより、チップ厚/基板厚が厚い組合わせでは,圧着温度からの冷却によってバンプ電極接触面に高い圧縮応力が作用し,それに伴いバンプ接触面に大きな塑性ひずみを生じている。したがって,下限温度から再加熱されるとチップ厚/基板厚が薄い組合わせに比べてかなり低温側で圧縮の接触応力がゼロになり,電気的接続が保てなくなってしまうことがわかる。さらに,チップ厚/基板厚が厚い組合わせでは,本解析で定義している下限温度(−55℃)に達する前の冷却過程の途中から,バンプ接触面の接触応力の減少が始まっているが,薄い組合わせの場合には下限温度まで圧縮の接触応力の減少を生じ難い。以上の有限要素法による検討結果から,上記に述べたメカニズムが定量的に検証されていることがわかる。このように薄いチップを用いることが好ましい。
【0029】
図2は本発明における第一の実施形態を示した断面図である。バンプ電極1がエリアアレイ状またはペリフェラル状に形成されたLSIチップ2を,LSIチップ上に形成されているバンプ電極1と同配置でメッキが施された電極パッド3が形成されている基板4上に,接着材5を介して熱圧着により搭載される。接着材にはNi粒子や樹脂状粒子に導電性のメタライズを施したような導電性粒子が混在した異方性導電性接着材や導電性粒子が混在しない非導電性接着材でもよい。接着材の線膨張係数が大きくなると微細なバンプ電極の塑性変形が加速されるため,接着材の室温における線膨張係数が20ppm以上,50ppm以下の特性を持つ材料であることが望ましい。
【0030】
熱圧着時の上記接着材5の硬化反応および熱圧着温度からの熱収縮により,バンプ電極1/基板電極3間の接触面に接触圧力が作用し電気的導通が達成される。バンプ電極1/基板電極3の接続は一般には100μmピッチ以下の場合に適用されるが、60μmピッチ以下の微細なバンプ電極に対する接続に対して本発明は特に効果的である。なお、ピッチの下限はプロセス上の制約などで定めることができる。
【0031】
例えば、バンプ形成プロセスの容易性の観点からは、10μmピッチ以上であることが好ましい。LSIチップ2上に形成されるバンプ電極1は金ワイヤを用いたスタッドバンプ方式や,より狭ピッチな接続においては金めっきにより形成される。金以外の材料を電極材料として用いることも可能であるが,接触導通構造であるため,表面状態が安定な元素で電極が構成された方がよい。搭載される基板4はガラス系,セラミック系,有機系(テープ基板含む)いずれの基板でも可能であり,基板表層にはLSIチップ2のバンプ電極1と同一ピッチで基板電極配線3が形成されている。
【0032】
有機系基板に搭載される場合,基板電極直下の基板材料のガラス転移温度が100℃以下に存在すると,LSIチップの動作環境や耐湿試験環境においてバンプ電極接触面の応力緩和が生じて接続信頼性を悪化させるため,上記基板材料のガラス転移温度は100℃以上,250℃以下にのみ存在する材料であることが望ましい。
【0033】
さらに基板配線3間の絶縁のためレジスト層6が形成されるが,LSIチップ1の搭載領域は上記接着材5で封止されるため搭載領域にはレジスト層6が無くてもよい。搭載されているLSIチップ1及び基板4は、図9に示すように単位モーメント力に対して曲げ曲率が形成される厚さで構成されるため、バンプ電極1搭載部直上または直下にLSIチップ2および基板4には、バンプ電極1を支点とした上記接着材5の熱収縮に伴う曲げモーメント力が作用する。このため図2に示したような曲げ曲率r1,r2が形成される。
【0034】
したがってバンプ電極1搭載部と単に上記接着材5で封止されている部分の厚さ方向の絶対値t1,t2は異なることになり,バンプ電極1搭載部の搭載基板4を含めた総厚さt1は,バンプ電極1が無い部分の総厚さt2より厚くなるように構成される。
【0035】
または、搭載基板4のLSIチップ2の側の主面からLSIチップ2の搭載基板側の主面と反対側の主面までの厚を見た場合、バンプ電極1の位置する領域はその周囲よりも厚くなるよう形成される(t11に対するt21)。
【0036】
また、LSIチップ2のバンプ電極1が位置する(積層方向に見て重なる配置になる)領域において、前記搭載基板表面から前記LSIチップのバンプ電極2が配置される主面と反対側の主面までの厚さの最も大きい部分と小さい部分との差が20nm以上である(t11とt12との差)。これにより、小型で効率的な実装された半導体装置を作成できる。より好ましくは、強度を確保する観点から、差が100nm以下であることが好ましい。
【0037】
また、LSIチップ2のうちバンプ電極1が位置する(積層方向に見て重なる配置になる)領域の代わりに、比較のし易さの観点から、LSIチップ2のうち、前記バンプ電極1に対応して基板側に形成される電極パッドのような基板電極3が位置する(積層方向に見て重なる位置になる)領域について前記差を見ることもできる。ここで、前記搭載基板表面から前記LSIチップのバンプ電極2が配置される主面と反対側の主面までの厚さの最も大きい部分と小さい部分との差が20nm以上である(t11とt13との差)。より好ましくは、強度を確保する観点から、差が100nm以下であることが好ましい。
【0038】
このように、測定しやすさの観点から、搭載基板表面とは、バンプ電極に対応するパッド電極のような基板電極3を有する場合はその表面から測定することができるものとする。
【0039】
または、LSIチップ2のバンプ電極1が形成された主面或いは前記主面の反対側の主面であって、前記バンプ電極1が位置する領域は、前記バンプ電極1が位置する領域の周囲の領域よりも大きな曲率を有する。前記の周囲の領域として、前記バンプ電極1の周囲であればよい。例えば、LSIチップ2の端部近傍にバンプ電極1が配置されているタイプの素子の場合は、素子の一つの辺の端部近傍に設置されたバンプ電極1と、その対向する辺の端部に設置されたバンプ電極1との中央部における曲率を比較することができる。或いは、素子の中央部を通るようにバンプ電極1が配置されている場合は、バンプ電極1とLSIチップ2端部との中央分での曲率を比較することができる。
【0040】
例えば、具体的には、前記突起電極によって電気的に接続されている領域の直上直下の前記半導体素子裏面(バックグラインド面)あるいは搭載基板裏面に曲げ曲率が形成され,厚さ方向に撓んでいる状態であってよい。
【0041】
先の図9で示したように、LSIチップ1の厚さについては0.1mm以下,ガラスエポキシ等有機系の基板4の厚さについては0.2mm以下であると、その効果が劇的に上昇するため望ましく、いずれか一方が達成されている場合でもよい。なお、バンプ電極の高さは、10μm以上であることができる。或いは更に、50μm以下であることができる。
【0042】
ずしもLSIチップ1と搭載基板4の両側に曲げ曲率r1,r2が形成される必要はなく,図1の実施例で示すように,LSIチップ1だけをより薄くしてLSIチップ1側にのみ、もしくはLSIチップ1側の方が搭載基板4よりも大きな曲げ曲率r1が形成された構造でもよい。さらに,バンプ電極1を含む接着材5の領域が曲げに対する中立軸位置になるように,例えば有機系の搭載基板厚さが0.3mmの場合には,チップ厚さは75μm〜105μm(基板厚さの0.25〜0.35倍)の範囲で(より薄い側で)形成されるのが望ましい。本実施例では搭載されたLSIチップ1は1チップであるが,面内に複数のLSIチップを本実装形態で実装された場合においても同様である。
【0043】
図3は本発明における実施形態の第一の実装例を示した断面図である。基本的には図1の実施例と同様の構造を有するが、本実施例においては、配線基板4の裏面にははんだボール11を形成するための配線パターンが形成されており,はんだボール11が配線基板4に搭載されたBGA(Ball Grid Array)パッケージとして提供される。これを提供された先のマザーボード10にはんだボール11を介して一括リフローされ電気的に接続される。あるいは,はんだボール11を搭載しないパッケージとして提供し,これを提供先マザーボード上に塗布されたはんだペーストではんだボールを介さず実装するLGA(Land Grid Array)構造で一括リフローされ電気的に接続されてもよい。このようにすることにより、小型で配線長の短くて、LSIチップ1の変形容易のためマザーボードに連絡するはんだボールへの応力集中を緩和できるので、外力等にも強い、信頼性の高いBGAパッケージを形成することができる。
【0044】
図4は本発明における実施形態の第二の実装例を示した断面図である。基本的には前記図3の構造と共通するが、本実施例では、直接提供先のマザーボード(フレキ基板等)へフリップチップ接続される構造とする。前記同様に、マザーボードへの接続部への応力集中を抑制できる。
【0045】
後述するように,本発明に係わる実装構造は,LSIチップ搭載エリアの部分加熱のみ(ツール側からの加熱のみ)で熱圧着を行った方が接続信頼性上も有利な構造であるので,図3に示したような個々のパッケージのインターポーザ用配線基板への搭載だけでなく,図4に示すように直接提供先のマザーボード(フレキ基板等)へフリップチップ接続されてもよい。ステージ側を加熱する必要がない(少なくともはんだの溶融温度に達する温度まで加熱する必要がない)ため,はんだ等で実装された他の部品との混載も可能である。
【0046】
図5は本発明における第二の実施形態を示した断面図である。本実施例の基本構造は第一の実施例と同様であるが,本実施例では、第一の実施例に示した構造で搭載されたLSIチップ2の上面に,さらに別のLSIチップ2aが積層されている。例えば一般的に使われているエポキシ系ダイボンディング用の接着材7を用いて熱圧着により積層される。熱圧着された後に,積層されたLSIチップ上のアルミ電極と基板上に形成された電極パッド間を金ワイヤ8によるワイヤボンディングによって電気的に接続される。
【0047】
積層されたLSIチップ2aの回路面が露出しているので,耐湿性を保持するためポッティングレジンかトランスファーモールドレジン9によってLSIチップ搭載領域が封止される。この際,積層される上段側のLSIチップ2aは下段のLSIチップ2と同等の厚さでも構わないが,下段のLSIチップ2より厚くしてもよい。これは同じシリコン同士を積層しているため,上段のLSIチップ2aの剛性の影響を下段のLSIチップ2がほとんど受けないためである。
【0048】
これにより、特にワイヤボンディングにより外部と電気的連絡を図るチップを搭載する場合に、上に載っているワイヤボンディングのチップ厚さを厚くすることにより、ワイヤボンディングの信頼性を高めることができ、高性能のパッケージを提供することに寄与することができる。
【0049】
なお、製造の都合によっては、積層される上段側のLSIチップ2aは下段のLSIチップ2と同等の厚さにしてもよい。
【0050】
図6は本発明における第三の実施形態を示した断面図である。本実施例は第二の実施例から,さらにもう一段別のLSIチップ2bが積層されている。プロセスも第二の実施例と同等であるが,この場合三段めのLSIチップ2bは二段目のLSIチップ2aより小さいチップサイズのもので構成されている。この場合においても,二段目,三段目のLSIチップ2a,2bは一段目のLSIチップ2と同等の厚さでもよいが,それより厚くても構わない。LSIチップの製品構成は,二段目と三段目のチップサイズのみでそれ以外の制限を受けるものではない。
【0051】
ただし,昨今デジタル家電に代表されるように,通信機能を搭載したRF(Radio Frequency)素子混載あるいはアナログ素子混載の高速処理システムへの需要が高まっており,特にアナログ素子では外力に対して特性がアナログ的に変化してしまうため,極力ストレスフリーに近い条件で実装されるのが望ましい。
【0052】
しかがって,アナログ素子混載のシステムを本実装形態で実現する場合には,三段積層構造の二段目にアナログ素子を搭載し,上下にはデジタル素子搭載されるのがよい。
【0053】
前記アナログ素子としては、例えばAD変換素子、RF素子であることができる。前記デジタル素子としては、例えばメモリ、マイコン、ASICであることができる。薄型LSIによる実装応力による特性変動が生じた場合、変動が信号変動となるためである。一方、デジタル素子はH/Lレベルに対して特性が決まるので特性変動の絶対値がH/Lレベルの範囲内であればよいためである。
【0054】
これはチップ同士の三段積層であるため,搭載基板が有機系でLSIチップと線膨張係数差が大きい場合や全体をトランスファーモールド封止した際に,二段目に積層されたLSIチップは上下のLSIチップによってそれらとの熱変形差が拘束されるため,二段目のLSIチップ2aにおいてはよりストレスフリーに近い実装が可能となり,実装構造においてより高機能なシステムを実現することができる。
【0055】
この具体例として、積層されたチップのうち、最下及び最上のチップでない中間の層のチップにアナログ素子を備え、前記搭載基板4にA/D変換素子などを備えたチップを設置する。
【0056】
または、例えば、積層されたチップのうち、実装応力の影響を抑制する観点から、アナログ素子を搭載するチップはデジタル素子を搭載するチップより厚くなるよう形成することができる。
【0057】
アナログ素子を有するチップは、デジタル素子を有するチップの上に位置することが好ましい。また、アナログ素子を有するチップの上に、デジタル素子を有するチップが位置することが好ましい。このように配置することにより、小型で外力による性能低下を抑制した半導体装置を形成することができる。たとば、前記半導体装置はAD変換素子を備えた画像処理装置であることができる。
【0058】
積上げられたLSIチップのうち、最も上に位置するチップにはA/D変換素子のようなアナログ回路を非設置とすることが好ましい。また、前記基板に隣接するベース半導体素子となるLSIチップには前記アナログ回路を非設置にすることが好ましい。
【0059】
これらの製造工程としては、半導体回路と外部を電気的に連絡するはんだバンプ等の外部端子が形成された半導体素子としてのLSIチップを提供する工程と、前記半導体素子が実装される配線が形成された基板を提供する工程と、半導体素子保持部材に保持された前記半導体素子と、基板保持部材に保持された前記基板とを接着材を介して加圧する加圧工程を有し、
前記加圧工程は、前記基板より前記半導体素子の温度を高くなるよう加熱する加熱工程を有する。
【0060】
例えば、半導体集積回路が形成されている半導体素子と、前記半導体素子が実装される配線基板と、前記半導体素子と前記配線基板が、前記半導体素子上に形成された複数の突起電極によって,前記配線基板に形成された複数の基板電極と電極間の金属接合ではなく接触によって電気的に接続される半導体装置を製造する際に、前記配線基板の半導体素子搭載領域に,シート状または液状の接着材を仮圧着または仮塗布し,前記突起電極が形成された半導体素子を搭載基板に熱圧着するようにすることができる。その際に、例えば、前記半導体素子を圧着するツール側のみから加熱し,搭載基板が設置されているステージ側は加熱されない条件で熱圧着される。具体的には以下に詳述する。
【0061】
図7は,本発明による実施例の製造方法を示す断面図である。一般的に使用されているフリップチップボンダーにより熱圧着が実施されるが,まずステージ13上に配線基板4を搭載し,LSIチップ2の搭載領域にシート状または液状の接着材5を仮圧着または仮塗布される。次に,ボンディングツール12によってLSIチップ2がピックアップされ,LSIチップ2上に形成されたバンプ電極1と配線基板4上に形成された基板電極が位置合わせされる。位置合わせが完了したらLSIチップ2は配線基板4に熱を加えながら圧着され,電気的な導通とLSIチップ回路面の封止が一括で行われる。圧着時間は圧着温度に依存するが,一般的には10秒〜30秒程度で,圧着温度が高い程短時間で接着材の硬化反応が完了し,圧着プロセスが終了する。圧着温度は,一般的にLSIチップ搭載領域の基板表面に熱電対を取り付けた状態で実際の熱圧着プロセスを実行し,そこで計測された温度で定義される。この際,圧着温度はステージ側を加熱せず,ツール側からの熱供給のみによって定義されるのが望ましい。
【0062】
この理由を以下に説明する。他のフリップチップ接続方法として,一般に金属結合を形成して電気的導通を達成する接続方法(金/金接続,金/はんだ接続等)は,LSIチップ側に形成したバンプ電極だけでなく,搭載基板側の電極も圧着初期段階で所定温度に加熱されていないと,熱圧着時に金属結合が形成されないため,ツール側とステージ側の両方を加熱して,両面から熱を供給しながら圧着が行われる。この場合,LSIチップや搭載基板を含めた実装系全体がほぼ均一に所定温度に達してしまうため,特にLSIチップと線膨張係数差の大きい有機系の配線基板に実装した場合には,熱圧着完了後の室温までの冷却過程における熱収縮差によってバンプ接続界面に負荷が集中し,初期段階でバンプ電極の接合界面が破損してしまう場合がある。しかし,本発明に係わる実装方法においては,単にバンプ電極と基板電極間の接触によって電気的導通が達成される構造であるので,熱圧着によって接着材の硬化反応さえ完了すればよい。したがって,熱圧着を行う際にツール側からのみ熱を供給して,接着材の領域が硬化反応に必要な温度に達すれば,ステージ側を加熱する必要必ずしもない。熱の流れをツール側からの片面加熱にすることによって,LSIチップから配線基板方向に対して温度勾配を生じ,特に有機系の配線基板は熱伝導がLSIチップに比べて悪いので,LSIチップ側に対して基板側の温度上昇が抑制され,熱圧着後のLSIチップと配線基板との熱収縮差が実質的に緩和されるので,接着界面の応力も緩和され,先に述べたような両者のバイメタル変形に伴う接続信頼性上の不具合も回避することが可能となる。
【0063】
【発明の効果】
本発明により外部端子と対応する基板との高信頼な電気的接続構造を備えた半導体装置を提供することができる。
【図面の簡単な説明】
【図1】本発明の第一の実施形態を示す断面図
【図2】本発明の第一の実施形態を示す断面図
【図3】本発明の実施形態による第一の顧客先実装例を示す断面図
【図4】本発明の実施形態による第二の顧客先実装例を示す断面図
【図5】本発明の第二の実施形態を示す断面図
【図6】本発明の第三の実施形態を示す断面図
【図7】本発明の実施形態の製造方法を示す断面図
【図8】本発明の高信頼接続メカニズムを説明する断面図
【図9】単位モーメント力に対する曲げ曲率を算出した図
【図10】携帯機器実装に伴う基板曲げ変形に対して高信頼接続メカニズムを説明する断面図
【図11】温度サイクル時にバンプ電極接触面に発生する接触応力変化と塑性ひずみ変化を有限要素法による接触解析により算出した図
【符号の説明】
1 バンプ電極
2 LSIチップ
3 基板電極
4 搭載基板
5 接着材
6 レジスト層
7 ダイボンド用接着材
8 金ワイヤ
9 封止樹脂
10 マザーボード
11 圧着ツール
12 搭載ステージ
[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor device, and more particularly to a semiconductor device in which a semiconductor element and a substrate are fixed with an adhesive.
[0002]
[Prior art]
SiP (System in Package) technology 1), which realizes a high-performance system by mounting existing LSI products at high density and narrow pitch with advanced packaging technology, has attracted attention. As a technology for mounting (connecting) an LSI and a substrate at a narrow pitch, there is a solder bump bonding by C4 (Controlled Collapse Chip Connection) 2) which has been widely applied to a connection pitch of 200 to 300 μm or more. On the other hand, there is a flip chip technology using gold bumps as a bump connection technology with a pitch of 200 μm or less, which is difficult to realize with solder. For this bonding method using gold bumps, metal radical bonding technology such as gold / gold bonding 3) and gold / solder bonding 4), ACF (Anisotropic Conductive Film), ACP (Anisotropic Conductive Paste), etc. were used. There are non-metaradical bonding technologies. Among these, non-metaradical bonding can achieve the electrical conduction between the bump / electrode and the sealing process with a single low-temperature thermocompression bonding and can be connected lead-free, so low-pitch connection can be achieved at low cost. It is regarded as a promising environment-friendly packaging technology. The mounting structure using ACF has been adopted as a method of connecting a driver IC for liquid crystal to a glass substrate, but in recent years it has been widely applied as a technology that enables narrow pitch connection to an organic substrate at low cost. Is underway.
[0003]
In non-metaradical bonding using ACF or the like, the electrical connection is achieved by contact between the gold bump and the electrode on the substrate, instead of being bonded by an alloy as in solder connection. There is a problem that if the contact pressure is lost within the guaranteed temperature range due to the influence of the thermal expansion difference between the metal bump electrodes and the adhesive that seals them, there is a problem of electrical disconnection. On the other hand, there are several inventions for improving the bonding reliability considering this bonding form. Or It is disclosed. For example, in Japanese Patent Application Laid-Open No. 11-067832, in flip chip bonding using ACF (anisotropic conductive resin), for example, the ACF material is made equal to or less than the linear expansion coefficient of gold as a bump electrode. Therefore, it offers a manufacturing method that improves connection reliability. Also, JP In Japanese Patent Laid-Open No. 2001-308230, flip-chip bonding is achieved by reducing the linear expansion coefficient of the material that seals the entire LSI chip region, rather than the linear expansion coefficient of the material that seals the flip-chip bonding portion by the gold bump. The manufacturing method which improves the connection reliability of a part is provided.
[0004]
[Problems to be solved by the invention]
In these structures, the thermal contraction of the material that sealed the flip chip joints with gold bumps caused compression stress on the bump contact surface to achieve electrical continuity. The contact stress of the bumps is reduced by the thermal expansion of the material, which is thought to stabilize the connection reliability by suppressing the surrounding low thermal expansion sealing resin.
[0005]
Japanese Patent Laid-Open No. 11-067832 Gazette In the invention provided in the above, since the general coefficient of linear expansion of gold is around 14 ppm, an organic material that can be used as a physical property can be used as a binder material that can achieve physical properties equivalent to or lower than those described above. It will be greatly limited. Further, when the linear expansion coefficient of the ACF material is smaller than that of the gold bump, sufficient compressive stress is not generated at the contact interface of the bump at the time of pressure hardening, and the initial bonding reliability may not be sufficiently obtained.
[0006]
further, JP 2001-308230 Gazette In the invention provided in the above, sealing the whole with a low thermal expansion resin suppresses thermal shrinkage of the sealing resin in the flip chip region even during cooling after sealing. In this case, the effect of increasing the connection margin is not so great.
[0007]
Each of the above-described inventions is an invention whose main purpose is to prevent the compressive stress on the bump contact surface from being reduced by heating and heating such as a temperature cycle test and a high temperature standing test. However, due to the recent application of flip chip connection to an organic substrate, connection reliability between LSI chips and organic substrates with a large difference in linear expansion coefficient is reduced not only during heating and heating but also during cooling. There is a fear. This is because the bimetal phenomenon due to the difference in linear expansion coefficient between the two causes warpage during the cooling process and decreases the contact stress at the bump electrode in the corner region.
[0008]
In addition, because it is used for mobile devices such as mobile phones, the mounting board is built in not only due to the conventional temperature cycle resistance and moisture resistance, but also due to the deformation of the case and the impact when dropped. It is desired to prevent the deformation due to the external force and the deterioration of the connection reliability of the LSI mounted on the substrate.
[0009]
An object of the present invention is to provide a semiconductor device that can solve the above-described problems and has a highly reliable electrical connection structure between an external terminal and a corresponding substrate.
[0010]
[Means for Solving the Problems]
Thus, according to the present invention, it is possible to achieve flip chip connection with a narrow pitch of 50 to 60 μm or less with low cost and high reliability. Specifically, since the plastic deformation of the bump electrode can be suppressed, it is possible to design a long life for the temperature cycle test, and it is strong against the external bending force of the mobile device mounting and can reduce the stress at the bonding interface. Therefore, the effect of suppressing the occurrence of migration due to moisture absorption is enhanced.
[0011]
Further, it is possible to achieve a highly reliable connection suitable for further thinning of the future mounting structure, multi-chip structure, and three-dimensional laminated structure.
[0012]
The present invention relates to, for example, a semiconductor device including a substrate laminated via an external terminal and an adhesive formed around the external terminal, and a main surface on which the wiring of the semiconductor element and the external terminal are formed from the substrate surface The region where the thickness to the main surface on the opposite side is formed so that the region where the external terminal is located is thicker than the surrounding region.
[0013]
In particular, the region where the first external terminal of the first semiconductor element is disposed is the largest thickness from the substrate surface to the main surface opposite to the main surface where the external terminal of the semiconductor element is located. The difference between the large portion and the small portion is 20 nm or more. Alternatively, the difference is 100 nm or less.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below. In addition, this invention is not restricted to the form described below, It does not prevent improvement and correction using a well-known technique.
(1) As one embodiment, a semiconductor element on which a semiconductor integrated circuit is formed, a wiring board on which the semiconductor element is mounted, the semiconductor element and the wiring board are formed on the semiconductor element. A plurality of protruding electrodes electrically connected to a plurality of substrate electrodes formed on the wiring substrate, and a semiconductor device made of an adhesive formed so as to fill a gap between the semiconductor element and the wiring substrate In which the total thickness in the thickness direction in the region or position electrically connected by the protruding electrode is a region in which the protruding electrode is not formed due to the bending deformation of the semiconductor element or the wiring board at the protruding electrode position Or it forms so that it may become thicker than the total thickness of the thickness direction in a position.
[0015]
The semiconductor element and the substrate are fixed by an adhesive in a region where the external terminals around the external terminals are not installed. On the other hand, the board corresponding to the external terminal has a region where a conductive fixing member such as solder is not installed. This means that substantially no fixing member such as solder is provided between the external terminal and the corresponding substrate. However, this only means that the fixing member is not substantially installed, and an adhesive filled around the external terminal in the manufacturing process is disposed between the external terminal and the corresponding substrate. It is allowed to be done. The main surface of the semiconductor element on which the external terminal is formed or the main surface on the opposite side of the main surface, and the area where the external terminal is located is larger than the area around the area where the external terminal is located Has curvature. The surrounding area may be any area around the external terminal. For example, in the case of an element of a type in which an external terminal is arranged near the end of a semiconductor element, the external terminal is installed near the end of one side of the element and the end of the opposite side. It is possible to compare the curvature at the center with the external terminal. Alternatively, if the external terminal is arranged so as to pass through the center of the element, the external terminal and the element end Central part with You can compare the curvature at.
[0016]
For example, specifically, a bending curvature is formed on the back surface of the semiconductor element (back grind surface) or the back surface of the mounting substrate immediately below the region electrically connected by the protruding electrode, and is bent in the thickness direction. .
(2) Alternatively, in the semiconductor device, the rate of change with respect to the thickness of the bending curvature generated in the semiconductor element or the wiring board is remarkably large due to the bending moment force generated by thermal contraction of the adhesive with the protruding electrode as a fulcrum. Thus, at least the semiconductor element is formed to have a thickness of 0.1 mm or less, or the wiring board made of an organic material has a thickness of 0.2 mm or less, or both.
(3) Alternatively, in the above semiconductor device, when the connection interval between the protruding electrode and the substrate electrode is 60 μm or less, the bonding between the protruding electrode and the substrate electrode is not a metal bond but is electrically connected by the contact of both electrodes. When conduction is achieved, the linear expansion coefficient at room temperature of the adhesive filling the periphery of the protruding electrode is in the range of 20 ppm or more and 50 ppm or less, and the glass transition temperature of the mounting substrate material immediately below the substrate electrode is 100 ° C. or more. When it is only in the range of 250 ° C. or less, the neutral axis position for bending deformation defined in the three-layer laminated structure composed of the total thickness of the wiring substrate, the total thickness of the semiconductor element, and the total thickness of the adhesive filling the gap is In the total thickness region of the adhesive, for example, when the semiconductor element is silicon and the wiring board is made of an organic material, the ratio of the thickness of the semiconductor element to the wiring board is set to 0. It is composed of a range of from 5 to 0.35.
[0017]
The mechanism of action and effect will be described below. FIG. 8 is a diagram conceptually showing the deformation state of each component when this mounting method is applied in the case of a combination of a thick chip and a thick substrate and in the case of a combination of a thin chip and a thin substrate. is there.
[0018]
The electrical continuity in this mounting form is obtained by thermocompression bonding a bump electrode formed on an LSI chip to a substrate electrode through an anisotropic conductive adhesive such as ACF or a nonconductive adhesive. This is achieved by generating a contact pressure on the contact surface between the bump electrode and the substrate electrode due to the curing shrinkage and thermal shrinkage from the pressure bonding temperature.
[0019]
Therefore, it is very important to achieve a reliable connection by stabilizing the contact pressure on the contact surface against changes in the material due to temperature changes and moisture absorption due to chip heat generation. With the recent miniaturization of the connection pitch, the miniaturization of the bump electrode size is also accelerated. For example, in order to achieve the 80 μm pitch connection, it is necessary to make the bump size at least 60 μm in diameter. With the finer bumps, the compressive stress on the contact surface due to the thermal shrinkage of the adhesive increases, making it easier to accelerate the plastic deformation of the bumps. When the plastic deformation (permanent deformation) of the bump electrode increases, the contact stress on the contact surface decreases rapidly when re-heated, and the connection reliability deteriorates.
[0020]
As shown in FIG. 8, in the combination of a thick chip and a thick substrate, since the rigidity of both of them is large, the load accompanying the thermal contraction of the adhesive concentrates on the bump electrode, and the plastic deformation of the bump (as shown in the figure) Permanent deformation) is accelerated. On the other hand, in the combination of a thin chip and a thin substrate, at room temperature level, the deformation due to the thermal shrinkage of the adhesive can be absorbed by the deformation of the LSI chip or the substrate as shown in the figure, so that an appropriate contact pressure is secured. In addition, the plastic deformation of the bump electrode can be suppressed.
[0021]
Furthermore, since the tensile / shear stress at the bonding interface that occurs with the thermal shrinkage of the adhesive is reduced, it is also effective in preventing the peeling of the bonding interface. Since the LSI chip and the substrate electrode are deformed so as to swell in the upper and lower end directions of the bump electrode connection portion within the range of elastic deformation, the deformation acts reversibly during reheating, and the contact pressure acting on the bump electrode contact surface is reduced. It is possible to suppress the decrease and improve the contact pressure on the bump contact surface, which is the initial design goal, in a more stable direction.
[0022]
FIG. 9 shows the result of calculating the bending curvature generated when a unit bending moment is generated in the LSI chip and the organic substrate from the beam theory of material mechanics. As shown in the figure, the curvature generated by the bending moment is inversely proportional to the elastic modulus and the cube of the thickness. . Figure As shown in Fig. 1, when the bending moment with the bump electrode as a fulcrum acts on the LSI chip due to the heat shrinkage of the adhesive, the bending curvature as shown in the figure r1 Is formed when the chip thickness is at most 0.3 mm or less, and it can be seen that the bending curvature rapidly increases when the chip thickness becomes thinner than 0.1 mm. In the case of an organic substrate, if it is at least 0.5 mm or less, it is thinner than 0.2 mm Kuna It can be seen that the bending curvature increases rapidly. That is, when connecting the LSI chip to the organic wiring board in this mounting form, the LSI chip is made thinner than 0.1 mm, or the substrate thickness (glass epoxy organic type) is made thinner than 0.2 mm. If implemented, it is possible to maintain the contact force of the bump electrode contact surface against temperature change by elastic deformation of the LSI chip or the wiring board while suppressing the plastic deformation of the bump electrode by the mechanism shown in FIG. Connection can be achieved . Thickness The lower limit of the thickness can be determined from the viewpoint of the manufacturing process and other viewpoints. As an example, it can be determined from the following viewpoints. About the said chip | tip, it is preferable that it is 0.01 mm or more from a viewpoint of ensuring the intensity | strength at the time of crimping | bonding. The substrate is preferably 0.05 mm or more from the viewpoint of ease of production.
[0023]
FIG. 10 conceptually shows the deformation state of each component when the substrate is deformed by an external force in the structure in which the LSI chip is mounted on the organic substrate using this mounting method. The figure shows the case where the mounted chip is thick and thin. When the mounting substrate is deformed as shown in the figure by an external force, the bending curvature is increased due to the entire warp deformation, and a reaction force is exerted on the LSI chip to return to the flat state.
[0024]
Therefore, if the LSI chip is thick and has high rigidity, the adhesive material loses the reaction force and the contact pressure on the bump electrode contact surface decreases. However, if the LSI chip is thin and has low rigidity, the decrease can be prevented.
[0025]
Furthermore, as a method for improving the connection reliability against the substrate deformation, as shown in the figure, the region filled with the adhesive including the contact bonding area of the bump electrode / substrate electrode is adjusted in the thickness direction against the bending deformation. The neutral axis position is effective. As a result, the deformation of the bonding interface between the LSI chip, the mounting substrate and the adhesive and the bump electrode / substrate electrode joint is suppressed against bending and warping deformation, and a more reliable connection structure can be achieved. . This can be easily defined from the beam theory of material mechanics and from the elastic modulus and thickness of each component. For example, when the LSI chip is silicon and the mounting substrate is made of an organic material (for example, glass epoxy), when the ratio of the thickness of the LSI chip to the mounting substrate is about 0.3, the joint interface between them is the neutral axis position. Become. Actually, since there is an adhesive material region including the connection interface by the bump electrode in the intermediate region, the thickness of the LSI chip and the mounting substrate is set so that the thickness ratio is in the range of 0.25 to 0.35. Is set, it is possible to suppress the deformation of the bump electrode interface against an external force or the like and achieve a highly reliable connection structure.
[0026]
A similar phenomenon may occur in the cooling process such as a temperature cycle test. Since the linear expansion coefficient of organic substrates (generally 10 to 20 ppm) is much smaller than that of LSI chips (silicon) (about 3 ppm), the mounting substrate receives external force during the cooling process from the thermocompression bonding temperature. Warpage deformation similar to that in the case of occurrence occurs. Therefore, when the rigidity of the LSI chip is large or when ΔT from the pressure bonding temperature is large, the contact stress on the bump electrode contact surface is reduced, which may deteriorate the connection reliability.
[0027]
FIG. 11 shows the result of structural analysis by the finite element method for quantitatively verifying the above generation mechanism and calculating the contact stress and plastic strain change acting on the bump electrode contact surface. In the figure, when the analysis is performed with a combination of a chip thickness of 0.4 mm and a substrate thickness of 1.0 mm (both conditions in which no bending curvature is formed with respect to unit moment force), the chip thickness is 0. In the case of analysis with a combination of 05 mm and a substrate thickness of 0.4 mm (conditions where the chip thickness can form a large bending curvature with respect to the unit moment force) are shown.
[0028]
Thereby, in the combination of thick chip thickness / substrate thickness, a high compressive stress acts on the bump electrode contact surface due to cooling from the crimping temperature, and accordingly, a large plastic strain is generated on the bump contact surface. Therefore, it can be seen that when reheated from the lower limit temperature, the compressive contact stress becomes zero on the low temperature side as compared with the combination of thin chip thickness / substrate thickness, and electrical connection cannot be maintained. Furthermore, in the combination of thick chip thickness / substrate thickness, the contact stress on the bump contact surface starts decreasing in the middle of the cooling process before reaching the lower limit temperature (-55 ° C) defined in this analysis. In the case of thin combinations, it is difficult to reduce the compressive contact stress to the lower limit temperature. From the above examination results by the finite element method, it can be seen that the mechanism described above has been quantitatively verified. It is preferable to use such a thin chip.
[0029]
FIG. 1 is a cross-sectional view showing a first embodiment of the present invention. An LSI chip 2 having bump electrodes 1 formed in an area array shape or a peripheral shape is formed on a substrate 4 on which electrode pads 3 are plated in the same arrangement as the bump electrodes 1 formed on the LSI chip. In addition, it is mounted by thermocompression bonding via an adhesive material 5. The adhesive may be an anisotropic conductive adhesive in which conductive particles such as conductive metallized Ni particles or resinous particles are mixed, or a nonconductive adhesive in which conductive particles are not mixed. Since the plastic deformation of fine bump electrodes is accelerated when the linear expansion coefficient of the adhesive increases, it is desirable that the adhesive has a characteristic that the linear expansion coefficient at room temperature is 20 ppm or more and 50 ppm or less.
[0030]
The contact pressure acts on the contact surface between the bump electrode 1 and the substrate electrode 3 due to the curing reaction of the adhesive 5 and the thermal contraction from the thermocompression bonding temperature during the thermocompression bonding, thereby achieving electrical conduction. Bump electrode 1 / substrate electrode 3 Connection Is generally applied when the pitch is 100 μm or less, but the present invention is particularly effective for connection to a fine bump electrode having a pitch of 60 μm or less. Note that the lower limit of the pitch can be determined by process restrictions.
[0031]
For example, the pitch is preferably 10 μm or more from the viewpoint of the ease of the bump formation process. The bump electrode 1 formed on the LSI chip 2 is formed by a stud bump method using a gold wire or by gold plating in a narrower pitch connection. Although materials other than gold can be used as the electrode material, it is preferable that the electrode be composed of an element having a stable surface state because of the contact conduction structure. The substrate 4 to be mounted can be any of glass, ceramic, and organic (including tape substrate) substrates, and substrate electrode wiring 3 is formed on the substrate surface layer at the same pitch as the bump electrodes 1 of the LSI chip 2. Yes.
[0032]
When mounted on an organic substrate, if the glass transition temperature of the substrate material directly below the substrate electrode is below 100 ° C, stress relaxation occurs on the bump electrode contact surface in the LSI chip operating environment and humidity resistance test environment, and connection reliability Therefore, it is desirable that the glass transition temperature of the substrate material is a material that exists only at 100 ° C. or more and 250 ° C. or less.
[0033]
Further, although a resist layer 6 is formed for insulation between the substrate wirings 3, the mounting region of the LSI chip 1 is sealed with the adhesive 5, and therefore the resist layer 6 may not be present in the mounting region. Since the mounted LSI chip 1 and the substrate 4 have a thickness that forms a bending curvature with respect to the unit moment force as shown in FIG. 9, the LSI chip 2 is directly above or immediately below the mounting portion of the bump electrode 1. The substrate 4 is also subjected to a bending moment force accompanying the thermal contraction of the adhesive 5 with the bump electrode 1 as a fulcrum. For this reason FIG. Bending curvatures r1 and r2 as shown in FIG.
[0034]
Therefore, the absolute values t1 and t2 in the thickness direction of the bump electrode 1 mounting portion and the portion simply sealed with the adhesive 5 are different, and the total thickness including the mounting substrate 4 of the bump electrode 1 mounting portion is different. t1 is configured to be thicker than the total thickness t2 of the portion where the bump electrode 1 is not provided.
[0035]
Alternatively, when the thickness from the main surface on the LSI chip 2 side of the mounting substrate 4 to the main surface on the opposite side of the main surface on the mounting substrate side of the LSI chip 2 is viewed, the region where the bump electrode 1 is located is from the periphery thereof (T21 with respect to t11).
[0036]
In a region where the bump electrodes 1 of the LSI chip 2 are located (overlapping in the stacking direction), the main surface opposite to the main surface on which the bump electrodes 2 of the LSI chip are disposed from the surface of the mounting substrate. The difference between the largest thickness portion and the smallest thickness portion is 20 nm or more (difference between t11 and t12). Thereby, a small and efficient mounted semiconductor device can be created. More preferably, from the viewpoint of securing strength, the difference is preferably 100 nm or less.
[0037]
Further, instead of the area of the LSI chip 2 where the bump electrode 1 is located (overlapping arrangement as viewed in the stacking direction), the LSI chip 2 corresponds to the bump electrode 1 from the viewpoint of ease of comparison. Thus, the difference can also be seen in a region where the substrate electrode 3 such as an electrode pad formed on the substrate side is located (is an overlapping position when viewed in the stacking direction). Here, the difference between the largest portion and the smallest portion from the mounting substrate surface to the main surface opposite to the main surface on which the bump electrode 2 of the LSI chip is disposed is 20 nm or more (t11 and t13). Difference). More preferably, from the viewpoint of securing strength, the difference is preferably 100 nm or less.
[0038]
Thus, from the viewpoint of ease of measurement, the mounting substrate surface can be measured from the surface when the substrate electrode 3 such as the pad electrode corresponding to the bump electrode is provided.
[0039]
Alternatively, the main surface of the LSI chip 2 on which the bump electrode 1 is formed or the main surface opposite to the main surface, and the region where the bump electrode 1 is located is around the region where the bump electrode 1 is located. Has a larger curvature than the region. What is necessary is just the circumference | surroundings of the said bump electrode 1 as said surrounding area | region. For example, in the case of an element of a type in which the bump electrode 1 is arranged near the end of the LSI chip 2, the bump electrode 1 installed near the end of one side of the element and the end of the opposite side It is possible to compare the curvature in the central portion with the bump electrode 1 placed on the surface. Alternatively, when the bump electrode 1 is disposed so as to pass through the central portion of the element, the curvatures at the center of the bump electrode 1 and the end portion of the LSI chip 2 can be compared.
[0040]
For example, specifically, a bending curvature is formed on the back surface of the semiconductor element (back grind surface) or the back surface of the mounting substrate immediately below the region electrically connected by the protruding electrode, and is bent in the thickness direction. It may be in a state.
[0041]
As shown in FIG. 9, the LSI chip 1 Thickness of About 0.1mm or less, organic substrate 4 such as glass epoxy Thickness of About 0.2 mm or less, it is desirable because the effect is dramatically increased, and either one may be achieved. The height of the bump electrode can be 10 μm or more. Alternatively, it can be 50 μm or less.
[0042]
Essential It is not always necessary to form the bending curvatures r1 and r2 on both sides of the LSI chip 1 and the mounting substrate 4, As shown in the embodiment of FIG. A structure in which only the LSI chip 1 is made thinner and only the LSI chip 1 side or a bending curvature r1 larger than the mounting substrate 4 on the LSI chip 1 side may be formed. Further, for example, when the thickness of the organic mounting substrate is 0.3 mm so that the region of the adhesive 5 including the bump electrode 1 becomes a neutral axis position with respect to bending, the chip thickness is 75 μm to 105 μm (substrate thickness It is desirable that it is formed in the range of 0.25 to 0.35 times the thickness (on the thinner side). In the present embodiment, the mounted LSI chip 1 is one chip, but the same applies when a plurality of LSI chips are mounted in this mounting form in the plane.
[0043]
FIG. 3 is a sectional view showing a first mounting example of the embodiment of the present invention. 1 basically has the same structure as that of the embodiment of FIG. 1, but in this embodiment, a wiring pattern for forming solder balls 11 is formed on the back surface of the wiring board 4. It is provided as a BGA (Ball Grid Array) package mounted on the wiring board 4. It is reflowed all at once through the solder balls 11 and electrically connected to the mother board 10 to which this is provided. Alternatively, the solder balls 11 are provided as a package that is not mounted, and this is reflowed and electrically connected in an LGA (Land Grid Array) structure in which the solder paste is applied on the target motherboard without using the solder balls. Also good. By doing so, it is small and has a short wiring length, and the stress concentration on the solder balls connected to the motherboard can be eased because the LSI chip 1 can be easily deformed. Can be formed.
[0044]
FIG. 4 is a sectional view showing a second mounting example of the embodiment of the present invention. Although this structure is basically the same as that shown in FIG. 3, in this embodiment, the structure is directly flip-chip connected to a mother board (flexible substrate or the like) to be provided. Similarly to the above, it is possible to suppress stress concentration on the connecting portion to the mother board.
[0045]
As will be described later, the mounting structure according to the present invention is advantageous in terms of connection reliability when thermocompression bonding is performed only by partial heating of the LSI chip mounting area (only heating from the tool side). In addition to mounting the individual packages on the interposer wiring board as shown in FIG. 3, they may be directly flip-chip connected to a mother board (flexible board or the like) as a provider as shown in FIG. Since it is not necessary to heat the stage side (at least it does not need to be heated to a temperature that reaches the melting temperature of the solder), it is possible to mix with other components mounted with solder or the like.
[0046]
FIG. 5 is a sectional view showing a second embodiment of the present invention. Although the basic structure of this embodiment is the same as that of the first embodiment, in this embodiment, another LSI chip 2a is formed on the upper surface of the LSI chip 2 mounted with the structure shown in the first embodiment. Are stacked. For example, they are laminated by thermocompression bonding using a commonly used adhesive 7 for epoxy die bonding. After thermocompression bonding, the aluminum electrodes on the stacked LSI chips and the electrode pads formed on the substrate are electrically connected by wire bonding with gold wires 8.
[0047]
Since the circuit surface of the stacked LSI chip 2a is exposed, the LSI chip mounting area is sealed with a potting resin or a transfer mold resin 9 in order to maintain moisture resistance. At this time, the upper LSI chip 2a to be stacked may have the same thickness as the lower LSI chip 2, but may be thicker than the lower LSI chip 2. This is because the same silicon is laminated so that the lower LSI chip 2 is hardly affected by the rigidity of the upper LSI chip 2a.
[0048]
This makes it possible to increase the reliability of wire bonding by increasing the thickness of the wire bonding chip on the chip, particularly when mounting a chip that is electrically connected to the outside by wire bonding. It can contribute to providing a performance package.
[0049]
Depending on the manufacturing convenience, the upper LSI chip 2a to be stacked may have a thickness equivalent to that of the lower LSI chip 2.
[0050]
FIG. 6 is a sectional view showing a third embodiment of the present invention. In this embodiment, another LSI chip 2b is stacked from the second embodiment. The process is the same as that of the second embodiment. In this case, the third-stage LSI chip 2b is configured with a chip size smaller than the second-stage LSI chip 2a. Also in this case, the second-stage and third-stage LSI chips 2a and 2b may have the same thickness as the first-stage LSI chip 2, or may be thicker. The product configuration of the LSI chip is not limited by the second and third chip sizes.
[0051]
However, recently, as represented by digital home appliances, there is an increasing demand for high-speed processing systems with mixed RF (Radio Frequency) elements or analog elements with communication functions. Especially, analog elements have characteristics against external forces. Since it changes in an analog fashion, it is desirable that it be mounted under conditions that are as stress-free as possible.
[0052]
Therefore, when an analog element mixed system is realized by this mounting form, it is preferable that the analog element is mounted on the second stage of the three-layer stacked structure, and the digital element is mounted on the upper and lower sides.
[0053]
The analog element can be, for example, an AD conversion element or an RF element. Examples of the digital element include a memory, a microcomputer, and an ASIC. This is because when the characteristic variation due to the mounting stress due to the thin LSI occurs, the variation becomes a signal variation. On the other hand, since the characteristics of the digital element are determined with respect to the H / L level, the absolute value of the characteristic variation only needs to be within the range of the H / L level.
[0054]
Since this is a three-stage stack of chips, when the mounting substrate is organic and the difference in linear expansion coefficient from the LSI chip is large, or when the whole is transfer molded, the LSI chip stacked in the second stage is Since the thermal deformation difference between them is constrained by the LSI chip, the second-stage LSI chip 2a can be mounted more stress-free, and a more functional system can be realized in the mounting structure.
[0055]
As a specific example, among the stacked chips, an analog element is provided in a chip in the middle layer which is not the lowest and uppermost chip, and a chip provided with an A / D conversion element or the like is installed on the mounting substrate 4.
[0056]
Alternatively, for example, from the viewpoint of suppressing the influence of mounting stress among the stacked chips, the chip on which the analog element is mounted can be formed to be thicker than the chip on which the digital element is mounted.
[0057]
The chip having analog elements is preferably located on the chip having digital elements. In addition, it is preferable that a chip having a digital element is positioned on a chip having an analog element. By arranging in this way, it is possible to form a semiconductor device that is small and suppresses performance degradation due to external force. For example, the semiconductor device can be an image processing device provided with an AD conversion element.
[0058]
Of the stacked LSI chips, it is preferable not to install an analog circuit such as an A / D conversion element in the uppermost chip. Further, it is preferable that the analog circuit is not installed in an LSI chip which is a base semiconductor element adjacent to the substrate.
[0059]
These manufacturing processes include a process of providing an LSI chip as a semiconductor element on which external terminals such as solder bumps for electrically connecting the semiconductor circuit and the outside are formed, and wiring on which the semiconductor element is mounted. Providing a substrate, and a pressing step of pressing the semiconductor element held by the semiconductor element holding member and the substrate held by the substrate holding member through an adhesive,
The said pressurization process has a heating process heated so that the temperature of the said semiconductor element may become higher than the said board | substrate.
[0060]
For example, a semiconductor element in which a semiconductor integrated circuit is formed, a wiring board on which the semiconductor element is mounted, and the semiconductor element and the wiring board are connected to each other by a plurality of protruding electrodes formed on the semiconductor element. When manufacturing a semiconductor device that is electrically connected by contact rather than metal bonding between a plurality of substrate electrodes formed on the substrate, a sheet-like or liquid adhesive is provided on the semiconductor element mounting region of the wiring substrate Can be temporarily pressure-bonded or temporarily coated so that the semiconductor element on which the protruding electrodes are formed is heat-bonded to the mounting substrate. At that time, for example, the semiconductor element is heated only from the tool side for pressure bonding, and the stage side on which the mounting substrate is installed is thermocompression bonded under the condition that it is not heated. Specifically, it will be described in detail below.
[0061]
FIG. 7 is a sectional view showing a manufacturing method of an embodiment according to the present invention. Thermo-compression is performed by a flip chip bonder that is generally used. First, the wiring substrate 4 is mounted on the stage 13, and a sheet-like or liquid adhesive material 5 is temporarily crimped or mounted on the mounting region of the LSI chip 2. Temporarily applied. Next, the LSI chip 2 is picked up by the bonding tool 12 and the bump electrodes 1 formed on the LSI chip 2 and the substrate electrodes formed on the wiring board 4 are aligned. When the alignment is completed, the LSI chip 2 is pressure-bonded while applying heat to the wiring board 4, and electrical conduction and sealing of the LSI chip circuit surface are performed at once. The crimping time depends on the crimping temperature, but is generally about 10 to 30 seconds. The higher the crimping temperature, the faster the curing reaction of the adhesive is completed and the crimping process is completed. The crimping temperature is generally defined by the temperature measured by performing an actual thermocompression bonding process with a thermocouple attached to the substrate surface in the LSI chip mounting area. At this time, it is desirable that the crimping temperature is defined only by the heat supply from the tool side without heating the stage side.
[0062]
The reason for this will be described below. As other flip chip connection methods, a connection method (gold / gold connection, gold / solder connection, etc.) that generally achieves electrical continuity by forming a metal bond is not only a bump electrode formed on the LSI chip side, but also mounted. If the electrode on the substrate side is not heated to a predetermined temperature in the initial stage of crimping, no metal bond is formed during thermocompression bonding. Therefore, crimping is performed while heating both the tool side and the stage side and supplying heat from both sides. Is called. In this case, the entire mounting system including the LSI chip and the mounting substrate reaches a predetermined temperature almost uniformly, and therefore, especially when mounted on an organic wiring substrate having a large difference in linear expansion coefficient from that of the LSI chip. Bump connection interface due to thermal shrinkage difference in cooling process to room temperature after completion Load is concentrated However, the bonding interface of the bump electrode may be damaged in the initial stage. However, in the mounting method according to the present invention, since electrical continuity is achieved simply by contact between the bump electrode and the substrate electrode, it is only necessary to complete the curing reaction of the adhesive by thermocompression bonding. Therefore, when thermocompression bonding is performed, heat is supplied only from the tool side, and the stage side must be heated if the adhesive region reaches the temperature required for the curing reaction. Is Not necessarily. By making the heat flow one-sided heating from the tool side, a temperature gradient is generated from the LSI chip to the wiring board direction, and especially the organic wiring board has a lower thermal conductivity than the LSI chip. In contrast, the temperature rise on the substrate side is suppressed, and the thermal shrinkage difference between the LSI chip after thermocompression bonding and the wiring board is substantially alleviated, so the stress at the bonding interface is also mitigated. It is possible to avoid problems in connection reliability due to the deformation of the bimetal.
[0063]
【The invention's effect】
According to the present invention, a semiconductor device including a highly reliable electrical connection structure between an external terminal and a corresponding substrate can be provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a first embodiment of the present invention.
FIG. 2 is a sectional view showing the first embodiment of the present invention.
FIG. 3 is a sectional view showing a first customer-side mounting example according to the embodiment of the present invention;
FIG. 4 is a cross-sectional view showing a second customer-side mounting example according to the embodiment of the present invention;
FIG. 5 is a sectional view showing a second embodiment of the present invention.
FIG. 6 is a sectional view showing a third embodiment of the present invention.
FIG. 7 is a cross-sectional view showing a manufacturing method according to an embodiment of the present invention.
FIG. 8 is a cross-sectional view illustrating the highly reliable connection mechanism of the present invention.
[Fig. 9] Calculation of bending curvature for unit moment force
FIG. 10 is a cross-sectional view for explaining a high-reliability connection mechanism against substrate bending deformation accompanying mounting of a mobile device.
FIG. 11 is a diagram in which contact stress change and plastic strain change generated on a bump electrode contact surface during a temperature cycle are calculated by contact analysis using a finite element method.
[Explanation of symbols]
1 Bump electrode
2 LSI chip
3 Substrate electrode
4 Mounting board
5 Adhesive
6 Resist layer
7 Adhesive for die bonding
8 gold wire
9 Sealing resin
10 Motherboard
11 Crimping tool
12 stage

Claims (9)

配線が形成された基板と、
前記基板上に配置され、半導体回路、及び前記半導体回路に電気的に連絡する複数の外部端子が形成された第一の半導体素子と、
前記第一の半導体素子と前記基板との間であり、前記外部端子の周囲に充填されて、前記第一の半導体素子を前記基板に固着している接着材と、
を備え、
前記接着材は、前記半導体素子の一主面の前記基板表面からの距離が、前記外部端子が位置する領域の距離よりも20nm以上小さくなる領域を有するように、前記接着材の収縮によって前記半導体素子を弾性変形させるとともに、前記弾性変形の力により前記外部端子を前記配線に押し付けて接触させることを特徴とする半導体装置。
A substrate on which wiring is formed;
A first semiconductor element disposed on the substrate and having a semiconductor circuit and a plurality of external terminals electrically connected to the semiconductor circuit;
An adhesive between the first semiconductor element and the substrate, filled around the external terminal, and fixing the first semiconductor element to the substrate;
With
The adhesive is contracted by the adhesive so that the distance between the main surface of the semiconductor element and the substrate surface is 20 nm or more smaller than the distance of the region where the external terminal is located. the element causes the elastic deformation, and wherein a more the external terminal contacting against the said wiring to the force of the elastic deformation.
請求項1において、
前記第一の半導体素子の前記外部端子が配置される領域は、前記基板表面から前記半導体素子の前記外部端子の位置する主面と反対側の主面までの厚さの最も大きい部分と小さい部分との差が100nm以下であることを特徴とする半導体装置。
In claim 1,
The region where the external terminal of the first semiconductor element is disposed is the largest and the smallest part from the substrate surface to the main surface opposite to the main surface where the external terminal of the semiconductor element is located. The difference between this and the semiconductor device is 100 nm or less.
請求項1において、
前記半導体素子の厚さは0.1mm以下、あるいは前記基板は、有機材料を有し、厚さが0.2mm以下であることを特徴とする半導体装置。
In claim 1,
The semiconductor device has a thickness of 0.1 mm or less, or the substrate has an organic material and has a thickness of 0.2 mm or less.
請求項1において、
外部端子の直径が60μm以下であることを特徴とする半導体装置。
In claim 1,
A semiconductor device, wherein an external terminal has a diameter of 60 μm or less.
請求項1において、
前記接着材の20℃における線膨張係数が20ppm以上,50ppm以下の範囲にあり、前記外部端子に対向する位置の前記基板の材料のガラス転移温度が100℃以上,250℃以下の範囲であることを特徴とする半導体装置。
In claim 1,
The linear expansion coefficient at 20 ° C. of the adhesive is in the range of 20 ppm or more and 50 ppm or less, and the glass transition temperature of the substrate material at the position facing the external terminal is in the range of 100 ° C. or more and 250 ° C. or less. A semiconductor device characterized by the above.
請求項1において、
前記半導体素子がシリコン部材上に前記回路が形成されており、前記配線基板が有機材料を主構成材料とし、前記基板に対する前記半導体素子の厚さの比率が0.25以上0.35以下であることを特徴とする半導体装置。
In claim 1,
The circuit is formed on a silicon member of the semiconductor element, the wiring board is mainly made of an organic material, and the ratio of the thickness of the semiconductor element to the substrate is 0.25 or more and 0.35 or less. A semiconductor device.
請求項1において、
前記第一の半導体素子の上に積層された複数の積上半導体素子を備え、
前記積上半導体素子にアナログ回路が形成され、
前記積上半導体素子の変形量は、前記第一の半導体素子の変形量よりも小さいことを特徴とする半導体装置。
In claim 1,
A plurality of stacked semiconductor elements stacked on the first semiconductor element;
An analog circuit is formed in the stacked semiconductor element,
The semiconductor device characterized in that the deformation amount of the stacked semiconductor element is smaller than the deformation amount of the first semiconductor element.
半導体回路と外部を電気的に連絡する外部端子が形成された半導体素子を提供する工程と、前記半導体素子が実装される配線が形成された基板を提供する工程と、半導体素子保持部材に保持された前記半導体素子と、基板保持部材に保持された前記基板とを接着材を介して加圧する加圧工程と、を有し、
前記加圧工程では、前記基板より前記半導体素子の温度を高くなるよう加熱し、前記半導体素子を、その一主面の前記基板表面からの距離が、前記外部端子が位置する領域の距離よりも20nm以上小さくなる領域を有するように、接着材の収縮によって弾性変形させ、前記弾性変形の力により前記外部端子を前記配線に押し付けて前記外部端子と前記配線とを接触させて導通を取り、前記接着材により前記基板に固着することを特徴とする半導体装置の製造方法。
A step of providing a semiconductor element in which an external terminal for electrically connecting a semiconductor circuit and the outside is formed; a step of providing a substrate on which a wiring for mounting the semiconductor element is formed; and a semiconductor element holding member. A pressing step of pressing the semiconductor element and the substrate held by the substrate holding member through an adhesive,
In the pressurizing step, the temperature of the semiconductor element is heated to be higher than that of the substrate, and the distance from the substrate surface of one main surface of the semiconductor element is larger than the distance of the region where the external terminal is located. Elastically deformed by contraction of the adhesive so as to have a region that is smaller than 20 nm, and the external terminal is pressed against the wiring by the elastic deformation force to bring the external terminal and the wiring into contact with each other, thereby conducting electrical connection. A method of manufacturing a semiconductor device, wherein the semiconductor device is fixed to the substrate with an adhesive.
請求項1において、
前記第一の半導体素子の上に、積層された半導体回路が形成された第二の半導体素子を備え、
前記積層された半導体素子のうち、前記基板に対向して設置される前記第一の半導体素子の厚さよりも、前記第二の半導体素子の厚さの方が厚く、前記第二の半導体素子の変形量は、前記第一の半導体素子の変形量よりも小さいことを特徴とする半導体装置。
In claim 1,
A second semiconductor element in which a stacked semiconductor circuit is formed on the first semiconductor element,
Of the stacked semiconductor elements, the thickness of the second semiconductor element is greater than the thickness of the first semiconductor element placed opposite to the substrate. A semiconductor device, wherein a deformation amount is smaller than a deformation amount of the first semiconductor element.
JP2002213249A 2002-07-23 2002-07-23 Semiconductor device and manufacturing method thereof Expired - Fee Related JP4243077B2 (en)

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