JP3829649B2 - Flip chip mounting method - Google Patents

Flip chip mounting method Download PDF

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Publication number
JP3829649B2
JP3829649B2 JP2001156117A JP2001156117A JP3829649B2 JP 3829649 B2 JP3829649 B2 JP 3829649B2 JP 2001156117 A JP2001156117 A JP 2001156117A JP 2001156117 A JP2001156117 A JP 2001156117A JP 3829649 B2 JP3829649 B2 JP 3829649B2
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Prior art keywords
resin
chip mounting
electrode pad
circuit board
film
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JP2002353276A (en
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一功 葛原
恭史 田中
忍 木田
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Panasonic Electric Works Co Ltd
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Matsushita Electric Works Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—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
    • H01L2224/10—Bump connectors; Manufacturing methods related thereto
    • H01L2224/15—Structure, shape, material or disposition of the bump connectors after the connecting process
    • H01L2224/16—Structure, shape, material or disposition of the bump connectors after the connecting process of an individual bump connector

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  • Electric Connection Of Electric Components To Printed Circuits (AREA)
  • Wire Bonding (AREA)
  • Non-Metallic Protective Coatings For Printed Circuits (AREA)

Description

【０００１】
【発明の属する技術分野】
本発明は、チップを回路基板上に実装するフリップチップ実装方法に関するものである。
【０００２】
【従来の技術】
従来のフリップチップ実装方法としては、例えば、図８に示すように、チップ２の実装面に設けた電極２２上に突起電極２１を形成し、チップ２をひっくり返して突起電極２１を回路基板１上の所定の位置に搭載しチップ２の突起電極２１と回路基板１表面に設けられた電極パッド１１とを接続させるような方法があげられる。
【０００３】
このフリップチップ実装では、チップ２と回路基板１との熱膨張係数の違いにより、チップ２の突起電極２１と回路基板１の電極パッド１１との接合部に応力がかかり、突起電極２１と電極パッド１１との接合がはずれる可能性があるため、チップ２と回路基板１の隙間には、樹脂（図示せず）を充填させることで、応力を樹脂中に分散させ接続の信頼性を向上させている。このため、フリップチップ実装の後に、樹脂の充填を行う工程が余分に必要となるため、コストアップにつながっている。
【０００４】
そこで、このような問題点を解決する手段としては、例えば、複数枚（図８においては２枚）のフィルム状樹脂４を回路基板１の電極パッド１１を有した表面に電極パッド１１を覆うように設け、チップ２の突起電極２１を複数枚のフィルム状樹脂４上から回路基板１に対し、突起電極２１が電極パッド１１に到達するようにチップ２をフィルム状樹脂４に押圧して接合するものがあげられる。
【０００５】
このようにフィルム状樹脂４を用いたフリップチップ実装方法は、チップ２の突起電極２１と回路基板１の電極パッド１１との接続と、樹脂の充填が一度で済むため効率的である。
【０００６】
【発明が解決しようとする課題】
ところが、上述のようなフィルム状樹脂を用いたフリップチップ実装方法においては、厚み３０μｍ程度のフィルム状樹脂を複数枚（通常２〜３枚）重ねて使用する必要がある。
【０００７】
これは、回路基板の電極パッドの厚みは通常３０μｍ以上あり、チップの突起電極も通常３０μｍ以上あるため、フリップチップ実装時のチップと回路基板との隙間は６０μｍ以上になるため、厚みが３０μｍ程度のフィルム状樹脂一枚では、チップと回路基板の隙間を埋めるのに不十分であるためである。
【０００８】
よって、フィルム状樹脂を複数枚重ねて使用する場合には、チップの突起電極は、複数枚のフィルム状樹脂を全て突き破って回路基板の電極パッドと接続する必要があるので、フィルム状樹脂が厚くなるにつれ、突起電極がフィルム状樹脂を突き破りにくくなり、その結果、突起電極と電極パッドとの間で接続不良が発生する可能性があるという問題点あった。
【０００９】
本発明は上記問題点を改善するためになされたものであり、回路基板とチップの隙間が大きくても、フィルム状樹脂を用いて安定したフリップチップ実装方法を提供することを目的とするものである。
【００１０】
【課題を解決するための手段】
請求項１に記載のフリップチップ実装方法は、チップ２の実装面に設けられた突起電極２１を、回路基板１上の所定の位置に搭載して該回路基板１の表面に設けられた電極パッド１１と電気的に接続させるフリップチップ実装方法において、樹脂層３を、前記回路基板１の表面に前記電極パッド１１の高さと略等しくなるように設ける工程と、少なくとも前記電極パッド１１上にフィルム状樹脂４を設ける工程と、前記突起電極２１が前記回路基板１の前記電極パッド１１に到達するように前記突起電極２１を前記フィルム状樹脂４に押圧することで該フィルム状樹脂４を破って前記突起電極２１と前記電極パッド１１とを接合する工程を含むことを特徴とするものである。
【００１２】
また、請求項２に記載のフリップチップ実装方法は、請求項１に記載の発明において、前記樹脂層３は、フィルム状樹脂を前記電極パッド１１を有する回路基板１表面に設けて後、該フィルム状樹脂を前記電極パッド１１と略等しい厚みとなるまで圧縮するようにして形成したことを特徴とするものである。
【００１３】
また、請求項３に記載のフリップチップ実装方法は、請求項１に記載の発明において、前記樹脂層３は、熱硬化性であることを特徴とするものである。
【００１４】
また、請求項４に記載のフリップチップ実装方法は、請求項３に記載の発明において、前記樹脂層３は、熱硬化性の樹脂を前記電極パッド１１の厚みより一旦厚く設けた後加熱して硬化させ、該加熱し硬化させた熱硬化性の樹脂を前記電極パッド１１の頭部が露出するまで研磨することにより形成したことを特徴とするものである。
【００１５】
また、請求項５に記載のフリップチップ実装方法は、請求項３に記載の発明において、前記樹脂層３は、熱硬化性の樹脂を前記電極パッド１１の厚みより一旦厚く設け、前記電極パッド１１の頭部が露出するまで熱硬化性の樹脂の上層部を除去して後、加熱し硬化させるようにして形成したことを特徴とするものである。
【００１６】
【発明の実施の形態】
以下に、本発明の実施形態を図面に基づき説明する。
【００１７】
本発明の第１実施形態を図１及び図２に基づいて説明する。図１は、本発明の第１実施形態に係るフリップチップ実装方法を示す説明図であり、図１（ａ）〜図１（ｄ）は、フリップチップ実装方法の工程を順に示している。また、図２は、図１のそれぞれの工程に対応する工程を上面図で説明したものである。
【００１８】
以下に、フリップチップ実装方法を図１に基づいて説明する。まず、図１（ａ）、図２（ａ）に示すように、ガラスエポキシ樹脂の回路基板１上には、３５μｍの銅箔（図示せず）を貼り付し、エッチングにより回路形成し、この回路上にＮｉとＡｕをそれぞれ厚み５μｍ、１μｍずつメッキして厚み４１μｍの電極パッド１１を６つ形成する。
【００１９】
次に、図１（ｂ）、図２（ｂ）に示すように、回路基板１の表面には、電極パッド１１の高さと略等しくなるまで、つまり厚み４１μｍ程度まで樹脂層３としてエポキシ樹脂を充填して、この樹脂層３上に厚み３０μｍ程度のフィルム状樹脂４としてフィルム状に加工したエポキシ樹脂を、回路基板１上の電極パッド１１及び樹脂層３を覆うように載置する。なお、フィルム状樹脂４は少なくとも電極パッド１１の上を覆うように設けられていればよい。
【００２０】
そして、図１（ｃ）、図２（ｃ）に示すように、チップ２の実装面には、予め電極Ａｌをメッキして６つの電極２２を設け、それぞれの電極２２上に突起電極２１として高さ４０μｍ程度の金バンプを設けておく。チップ２の回路基板１への搭載は、樹脂層３が硬化する前に、チップ２の突起電極２１を回路基板１の電極パッド１１に到達するように加圧し突起電極２１を変形させる。つまり、チップ２は、回路基板１の電極パッド１１上面とチップ２の実装面との距離が、フィルム状樹脂４の厚み、つまり３０μｍ程度以下になるようにチップ２をフィルム状樹脂４に押圧しフィルム状樹脂４を破るとともに、樹脂層３を構成するエポキシ樹脂を接合面から除去するようにして回路基板１と加熱接合する。この加熱により、樹脂層３及びフィルム状樹脂４は硬化される。また、突起電極２１と電極パッド１１とは、電気的に接続される。
【００２１】
ここで、第１実施形態においては、回路基板１表面に設ける樹脂層３としては、エポキシ樹脂を用いたが、ポリイミド樹脂や、シリコーン樹脂等であってもよい。また、フィルム状樹脂４としては、フィルム状に加工したエポキシ樹脂を用いたが、フィルム状に加工したポリイミド樹脂等であってもよい。
【００２２】
かかるフリップチップ実装方法においては、回路基板１の表面に電極パッド１１の高さと略等しくなるまで樹脂層３を充填し、電極パッド１１及び樹脂層３を覆うようにフィルム状樹脂４を載置し、フィルム状樹脂４上から回路基板１に対し、チップ２の突起電極２１が電極パッド１１に到達するようにチップ２をフィルム状樹脂４に押圧してフィルム状樹脂４を破って加熱接合するので、回路基板１とチップ２の隙間が大きくても、フィルム状樹脂４を用いて安定したフリップチップ実装が可能となる。
【００２３】
また、回路基板１の電極パッド１１及び樹脂層３を覆うように設ける一枚のフィルム状樹脂４の厚みは３０μｍ程度であるため、このフィルム状樹脂４をチップ２の突起電極２１で容易に突き破ることができる。
【００２４】
次に、回路基板１表面に設ける樹脂層３に関わる構成、形成方法が第１実施形態とは異なるような実施形態を、本発明の第２実施形態乃至第５実施形態として以下に説明する。なお、第２実施形態乃至第５実施形態においては、第１実施形態との共通部分の説明は、同一箇所には同一符号を付して省略する。
【００２５】
まず、回路基板１表面に設ける樹脂層３がエポキシ樹脂とは異なる参考例を、本発明の参考例として図３に基づいて説明する。図３は、本発明の参考例に係るフリップチップ実装方法を示す説明図である。
【００２６】
本参考例においては、第１実施形態において回路基板１表面に設けたエポキシ樹脂からなる樹脂層３の代わりに、異方性導電性材料を含んだ樹脂層３１を用いた構成である。
【００２７】
なお、参考例においては、樹脂層３１には厚さ４１μｍ程度のＡｇ粒子を含有したエポキシ樹脂を用いるが、他に、プラスチック球にＣｕ、Ｎｉ等をコーティングした粒子を含有したエポキシ樹脂等であってもよく、異方性導電性を有する樹脂であればよい。
【００２８】
なお、フリップチップ実装方法は、図３（ａ）〜図３（ｃ）に示すように、第１実施形態で示した方法と同様にして行う。
【００２９】
かかるフリップチップ実装方法においては、回路基板１表面に設けた樹脂層３１が異方性導電性材料を含んでいるので、チップ２の突起電極２１と回路基板１の電極パッド１１の間にフィルム状樹脂４が一部残っていても、樹脂層３１の有する導電性粒子を介して、チップ２の突起電極２１と回路基板１の電極パッド１１とを電気的に接続することが可能となる。
【００３０】
次に、回路基板１表面に設ける樹脂層３をフィルム状に加工した樹脂で形成するような実施形態を、本発明の第２実施形態として図４に基づいて説明する。図４は、本発明の第２実施形態に係るフリップチップ実装方法を示す説明図である。
【００３１】
図４（ａ）に示すように、第１実施形態において回路基板１表面に設けたエポキシ樹脂からなる樹脂層３の代わりに、フィルム状に加工したエポキシ樹脂からなるフィルム状樹脂３２を用いた構成である。
【００３２】
第２実施形態においては、フィルム状樹脂３２として、厚み５０μｍ程度のフィルム状に加工したエポキシ樹脂を用い、回路基板１の電極パッド１１を有する表面には、電極パッド１１を覆うようなフィルム状樹脂３２を載置する。その後、図４（ｂ）に示すように、例えば、加圧面が平らであり、サイズが回路基板１を覆うことができる所望の加圧用ツール１００を用いて、フィルム状樹脂３２が電極パッド１１と略等しい厚みになるまで圧縮、つまりフィルム状樹脂３２の厚みを９μｍ程度圧縮する。そして、図４（ｃ）に示すように、圧縮したフィルム状樹脂３２上に、更に第１実施形態にて用いた厚み３０μｍ程度のフィルム状樹脂４を載置する。
【００３３】
チップ２の回路基板１への搭載は、図４（ｄ）に示すように、第１実施形態で示した方法と同様にして行う。
【００３４】
かかるフリップチップ実装方法においては、回路基板１の電極パッド１１を有する表面に電極パッド１１を覆うようなフィルム状樹脂３２を電極パッド１１と略等しい厚みになるまで圧縮して設けることで、回路基板１表面に樹脂層３を容易に形成することができる。
【００３５】
次に、回路基板１に設ける樹脂層３の第１実施形態とは異なる形成方法を、本発明の第３実施形態として図５に基づいて説明する。図５は、本発明の第３実施形態に係るフリップチップ実装方法を示す説明図である。
【００３６】
図５（ａ）に示すように、樹脂層３として、回路基板１の電極パッド１１を有する表面に、電極パッド１１の厚みより１〜５μｍ程度薄くなるように、つまり厚みが３６〜４０μｍ程度となるようにエポキシ樹脂を、例えばディスペンサ１１０を用いて塗布して後加熱し硬化させ形成する。そして、図５（ｂ）に示すように、加熱し硬化したエポキシ樹脂及び電極パッド１１上に第１実施形態にて用いたフィルム状樹脂４を載置する。
【００３７】
チップ２の回路基板１への搭載は、図５（ｃ）に示すように、第１実施形態で示した方法と同様にして行う。
【００３８】
かかるフリップチップ実装方法においては、エポキシ樹脂を電極パッド１１の厚みより１〜５μｍ程度薄くなるように塗布して後加熱し硬化することで、回路基板１に樹脂層３を容易に形成することができる。
【００３９】
次に、第３実施形態とは異なる樹脂層３の形成方法を、本発明の第４実施形態として図６に基づいて説明する。図６は、本発明の第４実施形態に係るフリップチップ実装方法を示す説明図である。
【００４０】
図６（ａ）に示すように、回路基板１の電極パッド１１を有する表面に、樹脂層３として、エポキシ樹脂を、電極パッド１１を含む領域において電極パッド１１より厚く塗布した後、加熱し硬化する。そして、図６（ｂ）に示すように、加熱し硬化したエポキシ樹脂を、電極パッド１１の高さと略等しくなるまで研磨機（図示せず）を用いて機械的研磨を行う。そして、図６（ｃ）に示すように、研磨済みのエポキシ樹脂上に第１実施形態にて用いたフィルム状樹脂４を載置する。
【００４１】
チップ２の回路基板１への搭載は、図６（ｄ）に示すように、第１実施形態で示した方法と同様にして行う。
【００４２】
かかるフリップチップ実装方法においては、加熱し硬化したエポキシ樹脂を電極パッド１１の高さと略等しくなるまで研磨するので、電極パッド１１上面には余分なエポキシ樹脂が存在ぜず、エポキシ樹脂がチップ２の突起電極２１と回路基板１の電極パッド１１との間に入り込む可能性がなくなり、チップ２の突起電極２１と回路基板１の電極パッド１１との電気的接続が効率的に行われる。
【００４３】
次に、回路基板１に設ける樹脂層３に対する他の加工方法を、本発明の第５実施形態として図７に基づいて説明する。図７は、本発明の第５実施形態に係るフリップチップ実装方法を示す説明図である。
【００４４】
図７（ａ）、図７（ｂ）に示すように、回路基板１の電極パッド１１を有する表面に、樹脂層３として、エポキシ樹脂を、電極パッド１１を含む領域において電極パッド１１より厚く塗布した後、電極パッド１１の頭部が露出するまでエポキシ樹脂の上層部を、例えばスキージ１２０で取り除く。さらにこの後、電極パッド１１の表面は、例えば、減圧方式又は大気圧方式のプラズマクリーニング装置（図示せず）や、ＵＶオゾンを用いた洗浄装置（図示せず）等を用いて有機物を完全に取り除くための表面クリーニングを行う。このような表面クリーニングを行い電極パッド１１上の有機物を除去することで、突起電極２１と電極パッド１１との間の電気的接合を効率的に行うことができる。次に、エポキシ樹脂を加熱し硬化することにより、電極パッドの高さと略等しい樹脂層３を形成する。
【００４５】
そして、図７（ｃ）に示すように、研磨済みのエポキシ樹脂上に第１実施形態にて用いたフィルム状樹脂４を載置する。
【００４６】
チップ２の回路基板１への搭載は、図７（ｄ）に示すように、第１実施形態で示した方法と同様にして行う。
【００４７】
かかるフリップチップ実装方法においては、回路基板１表面にエポキシ樹脂を電極パッド１１より厚く塗布した後、電極パッド１１の頭部が露出するまでエポキシ樹脂の上層部を除去し、その後加熱し硬化するので、余分なエポキシ樹脂がチップ２の突起電極２１と回路基板１の電極パッド１１との間に入り込む可能性がなくなり、チップ２の突起電極２１と回路基板１の電極パッド１１との電気的接続が効率的に行われる。
【００４８】
【発明の効果】
上記のように本発明に係る請求項１に記載のフリップチップ実装方法にあっては、樹脂層を、前記回路基板の表面に前記電極パッドの高さと略等しくなるように設ける工程と、少なくとも前記電極パッド上にフィルム状樹脂を設ける工程と、前記突起電極が前記回路基板の前記電極パッドに到達するように前記突起電極を前記フィルム状樹脂に押圧することで該フィルム状樹脂を破って前記突起電極と前記電極パッドとを接合する工程を含むので、前記フィルム状樹脂を前記チップの前記突起電極で容易に突き破ることができるため、前記回路基板と前記チップの隙間が大きくても、前記フィルム状樹脂を用いて安定したフリップチップ実装方法を提供することができた。
【００５０】
また、請求項２に記載のフリップチップ実装方法にあっては、請求項１に記載の発明において、前記樹脂層は、フィルム状樹脂を前記電極パッドを有する回路基板表面に設けて後、該フィルム状樹脂を前記電極パッドと略等しい厚みとなるまで圧縮するようにして形成したので、前記回路基板の前記電極パッドを有する表面に設けた前記フィルム状樹脂を前記電極パッドと略等しい厚みになるまで圧縮して設けることで、前記回路基板表面に前記樹脂層を容易に形成することができるという効果を奏する。
【００５１】
また、請求項３に記載のフリップチップ実装方法にあっては、請求項１に記載の発明において、前記樹脂層は、熱硬化性であるようにしたので、前記回路基板に前記樹脂層を容易に形成することができるという効果を奏する。
【００５２】
また、請求項４に記載のフリップチップ実装方法にあっては、請求項３に記載の発明において、前記樹脂層は、熱硬化性の樹脂を前記電極パッドの厚みより一旦厚く設けた後加熱して硬化させ、該加熱し硬化させた熱硬化性の樹脂を前記電極パッドの頭部が露出するまで研磨することにより形成するようにしたので、前記加熱し硬化させた熱硬化性の樹脂を前記電極パッドの高さと略等しくなるまで研磨することで、余分なエポキシ樹脂が存在ぜず、前記電極パッド上面には余分な前記樹脂層が存在ぜず、前記樹脂層が前記チップの前記突起電極と前記回路基板の前記電極パッドとの間に入り込む可能性がなくなり、前記チップの前記突起電極と前記回路基板の前記電極パッドとの電気的接続が効率的に行われるという効果を奏する。
【００５３】
また、請求項５に記載のフリップチップ実装方法にあっては、請求項３に記載の発明において、前記樹脂層は、熱硬化性の樹脂を前記電極パッドの厚みより一旦厚く設け、前記電極パッドの頭部が露出するまで熱硬化性の樹脂の上層部を除去して後、加熱し硬化させるようにして形成するようにしたので、前記回路基板表面に前記樹脂層を前記電極パッドより厚く塗布した後、前記電極パッドの頭部が露出するまで前記樹脂層の上層部を除去し、その後加熱し硬化するので、余分な前記樹脂層が前記チップの前記突起電極と前記回路基板の前記電極パッドとの間に入り込む可能性がなくなり、前記突起電極と前記回路基板の前記電極パッドとの電気的接続が効率的に行われるという効果を奏する。
【図面の簡単な説明】
【図１】本発明の第１実施形態に係るフリップチップ実装方法を示す説明図である。
【図２】本発明の第１実施形態に係るフリップチップ実装方法を示す説明図（上面図）である。
【図３】本発明の参考例に係るフリップチップ実装方法を示す説明図である。
【図４】本発明の第２実施形態に係るフリップチップ実装方法を示す説明図である。
【図５】本発明の第３実施形態に係るフリップチップ実装方法を示す説明図である。
【図６】本発明の第４実施形態に係るフリップチップ実装方法を示す説明図である。
【図７】本発明の第５実施形態に係るフリップチップ実装方法を示す説明図である。
【図８】従来例に係るフリップチップ実装方法を示す説明図である。
【符号の説明】
１ 回路基板
２ チップ
３ 樹脂層
４ フィルム状樹脂
１１ 電極パッド
２１ 突起電極
２２ 電極
３１ 樹脂層
３２ フィルム状樹脂[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a flip chip mounting method for mounting a chip on a circuit board.
[0002]
[Prior art]
As a conventional flip chip mounting method, for example, as shown in FIG. 8, the protruding electrode 21 is formed on the electrode 22 provided on the mounting surface of the chip 2, and the protruding electrode 21 is turned over by turning the chip 2 over. There is a method in which the protruding electrode 21 of the chip 2 and the electrode pad 11 provided on the surface of the circuit board 1 are connected to each other at a predetermined position above.
[0003]
In this flip-chip mounting, due to the difference in thermal expansion coefficient between the chip 2 and the circuit board 1, stress is applied to the joint between the protruding electrode 21 of the chip 2 and the electrode pad 11 of the circuit board 1, and the protruding electrode 21 and the electrode pad 11 may be disconnected, so that the gap between the chip 2 and the circuit board 1 is filled with resin (not shown) to disperse the stress in the resin and improve the connection reliability. Yes. For this reason, an extra step of filling the resin after flip chip mounting is required, leading to an increase in cost.
[0004]
Therefore, as a means for solving such a problem, for example, a plurality (two in FIG. 8) of the film-like resin 4 is covered with the electrode pads 11 on the surface of the circuit board 1 having the electrode pads 11. The chip 2 is pressed against the film-like resin 4 so that the bump electrode 21 reaches the electrode pad 11 with respect to the circuit board 1 from the plurality of film-like resins 4. Things can be raised.
[0005]
As described above, the flip chip mounting method using the film-like resin 4 is efficient because the connection between the protruding electrode 21 of the chip 2 and the electrode pad 11 of the circuit board 1 and the filling of the resin are required only once.
[0006]
[Problems to be solved by the invention]
However, in the flip chip mounting method using the film-like resin as described above, it is necessary to use a plurality of (usually 2 to 3) film-like resins having a thickness of about 30 μm.
[0007]
This is because the thickness of the electrode pad on the circuit board is usually 30 μm or more and the protruding electrode of the chip is also usually 30 μm or more, so the gap between the chip and the circuit board when flip-chip mounting is 60 μm or more, and the thickness is about 30 μm. This is because one film-like resin is insufficient to fill the gap between the chip and the circuit board.
[0008]
Therefore, when a plurality of film-shaped resins are used in an overlapping manner, the protruding electrodes of the chip need to penetrate all of the plurality of film-shaped resins and be connected to the electrode pads of the circuit board. As a result, the projecting electrode hardly breaks through the film-like resin, and as a result, there is a problem in that a connection failure may occur between the projecting electrode and the electrode pad.
[0009]
The present invention has been made to remedy the above problems, and it is an object of the present invention to provide a stable flip chip mounting method using a film-like resin even when a gap between a circuit board and a chip is large. is there.
[0010]
[Means for Solving the Problems]
The flip chip mounting method according to claim 1, wherein the protruding electrode 21 provided on the mounting surface of the chip 2 is mounted at a predetermined position on the circuit board 1 and is provided on the surface of the circuit board 1. in 11 electrically connected to the flip chip mounting method for the resin layer 3, the circuit height and step substantially Ru provided to equal the to the front electrode pad 11 of the substrate 1, over said electrode pads 11 even without least the film-like resin and the film-like resin 4 set Keru step, the protruding electrode 21 as before Symbol protruding electrode 21 reaches the electrode pads 11 of the circuit board 1 by being pressed against the film-like resin 4 4 beating is characterized in it to contain a step of bonding the electrode pads 11 and the protruding electrode 21.
[0012]
According to a second aspect of the present invention, there is provided the flip chip mounting method according to the first aspect of the invention, wherein the resin layer 3 is formed by providing a film-like resin on the surface of the circuit board 1 having the electrode pads 11, and then the film. It is characterized in that the resin is compressed so as to have a thickness substantially equal to that of the electrode pad 11.
[0013]
According to a third aspect of the present invention, in the flip-chip mounting method according to the first aspect, the resin layer 3 is thermosetting.
[0014]
According to a fourth aspect of the present invention, in the flip-chip mounting method according to the third aspect, the resin layer 3 is heated after a thermosetting resin is provided once thicker than the electrode pad 11. It is formed by polishing and curing the thermosetting resin cured by heating until the head of the electrode pad 11 is exposed.
[0015]
According to a fifth aspect of the present invention, in the flip-chip mounting method according to the third aspect, the resin layer 3 is provided with a thermosetting resin that is once thicker than the electrode pad 11, and the electrode pad 11. The upper layer portion of the thermosetting resin is removed until the head portion is exposed, and then heated and cured.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0017]
1st Embodiment of this invention is described based on FIG.1 and FIG.2. FIG. 1 is an explanatory view showing a flip chip mounting method according to a first embodiment of the present invention, and FIGS. 1A to 1D sequentially show steps of the flip chip mounting method. FIG. 2 is a top view illustrating processes corresponding to the processes in FIG.
[0018]
The flip chip mounting method will be described below with reference to FIG. First, as shown in FIG. 1A and FIG. 2A, a 35 μm copper foil (not shown) is pasted on a circuit board 1 made of glass epoxy resin, and a circuit is formed by etching. Six electrode pads 11 having a thickness of 41 μm are formed by plating Ni and Au on the circuit in thicknesses of 5 μm and 1 μm, respectively.
[0019]
Next, as shown in FIG. 1B and FIG. 2B, an epoxy resin is applied to the surface of the circuit board 1 as the resin layer 3 until the surface of the circuit board 1 is substantially equal to the height of the electrode pad 11, that is, to a thickness of about 41 μm. An epoxy resin that is filled and processed into a film-like resin 4 having a thickness of about 30 μm is placed on the resin layer 3 so as to cover the electrode pads 11 and the resin layer 3 on the circuit board 1. The film-like resin 4 only needs to be provided so as to cover at least the electrode pad 11.
[0020]
Then, as shown in FIGS. 1C and 2C, the mounting surface of the chip 2 is provided with six electrodes 22 by previously plating the electrode Al, and the protruding electrodes 21 are formed on the respective electrodes 22. A gold bump having a height of about 40 μm is provided. When the chip 2 is mounted on the circuit board 1, the protruding electrode 21 of the chip 2 is pressed so as to reach the electrode pad 11 of the circuit board 1 and the protruding electrode 21 is deformed before the resin layer 3 is cured. That is, the chip 2 presses the chip 2 against the film-like resin 4 so that the distance between the upper surface of the electrode pad 11 of the circuit board 1 and the mounting surface of the chip 2 is equal to or less than the thickness of the film-like resin 4, that is, about 30 μm. The film-like resin 4 is broken, and the epoxy resin constituting the resin layer 3 is removed from the bonding surface and bonded to the circuit board 1 by heating. By this heating, the resin layer 3 and the film-like resin 4 are cured. Further, the protruding electrode 21 and the electrode pad 11 are electrically connected.
[0021]
Here, in the first embodiment, an epoxy resin is used as the resin layer 3 provided on the surface of the circuit board 1, but a polyimide resin, a silicone resin, or the like may be used. Moreover, although the epoxy resin processed into the film form was used as the film-form resin 4, the polyimide resin etc. which were processed into the film form may be sufficient.
[0022]
In such a flip chip mounting method, the surface of the circuit board 1 is filled with the resin layer 3 until the height of the electrode pad 11 is substantially equal, and the film-like resin 4 is placed so as to cover the electrode pad 11 and the resin layer 3. Since the chip 2 is pressed against the film-shaped resin 4 so that the protruding electrode 21 of the chip 2 reaches the electrode pad 11 from the film-shaped resin 4 to the circuit board 1, the film-shaped resin 4 is broken and heat-bonded. Even if the gap between the circuit board 1 and the chip 2 is large, stable flip chip mounting using the film-like resin 4 becomes possible.
[0023]
Further, since the thickness of one film-like resin 4 provided so as to cover the electrode pads 11 and the resin layer 3 of the circuit board 1 is about 30 μm, the film-like resin 4 is easily pierced by the protruding electrodes 21 of the chip 2. be able to.
[0024]
Next, the configuration related to the resin layer 3 provided on the circuit substrate 1, forming method will be described different embodiments from the first embodiment, the following as the second embodiment to the fifth implementation mode of the present invention . Incidentally, omitted in the second embodiment to the fifth implementation mode, description of the common parts of the first embodiment, the same portions are denoted by the same reference numerals.
[0025]
First, a reference example resin layer 3 provided on the circuit substrate 1 that is different from the epoxy resin will be described with reference to FIG. 3 as a reference example of the present invention. FIG. 3 is an explanatory view showing a flip chip mounting method according to a reference example of the present invention.
[0026]
Oite the present embodiment, instead of the resin layer 3 made of epoxy resin which is provided on the circuit substrate 1 in the first embodiment, a configuration in which a resin layer 31 containing the anisotropic conductive material.
[0027]
Incidentally, Oite the reference example, the resin layer 31 using an epoxy resin containing Ag particles having a thickness of about 41μm, but others, Cu plastic spheres, epoxy resin containing particles coated with Ni or the like Any resin having anisotropic conductivity may be used.
[0028]
The flip chip mounting method is performed in the same manner as the method shown in the first embodiment, as shown in FIGS. 3 (a) to 3 (c).
[0029]
In this flip chip mounting method, since the resin layer 31 provided on the surface of the circuit board 1 contains an anisotropic conductive material, a film shape is formed between the protruding electrode 21 of the chip 2 and the electrode pad 11 of the circuit board 1. Even if a part of the resin 4 remains, the protruding electrodes 21 of the chip 2 and the electrode pads 11 of the circuit board 1 can be electrically connected through the conductive particles of the resin layer 31.
[0030]
Next, an embodiment such as to form a resin obtained by processing the resin layer 3 provided on the circuit board first surface in film form, will be described with reference to FIG. 4 as a second implementation mode of the present invention. Figure 4 is an explanatory view showing a flip chip mounting method according to a second implementation embodiment of the present invention.
[0031]
As shown in FIG. 4A, a configuration using a film-like resin 32 made of an epoxy resin processed into a film instead of the resin layer 3 made of an epoxy resin provided on the surface of the circuit board 1 in the first embodiment. It is.
[0032]
In the second implementation embodiment, as a film-like resin 32, using the processing epoxy resin thickness 50μm about a film-like, the surface having the electrode pads 11 of the circuit board 1, a film shape as to cover the electrode pads 11 Resin 32 is placed. Thereafter, as shown in FIG. 4B, for example, the film-like resin 32 is bonded to the electrode pad 11 by using a desired pressing tool 100 having a flat pressing surface and a size that can cover the circuit board 1. Compress until the thickness is substantially equal, that is, compress the thickness of the film-like resin 32 by about 9 μm. Then, as shown in FIG. 4C, the film-like resin 4 having a thickness of about 30 μm used in the first embodiment is placed on the compressed film-like resin 32.
[0033]
As shown in FIG. 4D, the chip 2 is mounted on the circuit board 1 in the same manner as in the first embodiment.
[0034]
In such a flip-chip mounting method, the circuit board 1 is compressed and provided on the surface of the circuit board 1 having the electrode pads 11 so as to cover the electrode pads 11 until it has a thickness substantially equal to that of the electrode pads 11. The resin layer 3 can be easily formed on one surface.
[0035]
Next, a different method of forming the first embodiment of the resin layer 3 provided on the circuit board 1 will be described with reference to FIG. 5 as a third implementation mode of the present invention. Figure 5 is an explanatory view showing a flip chip mounting method according to a third implementation mode of the present invention.
[0036]
As shown in FIG. 5A, the resin layer 3 is formed on the surface of the circuit board 1 having the electrode pads 11 so as to be thinner by about 1 to 5 μm than the thickness of the electrode pads 11, that is, the thickness is about 36 to 40 μm. An epoxy resin is applied using, for example, a dispenser 110 and then heated and cured. Then, as shown in FIG. 5B, the film-like resin 4 used in the first embodiment is placed on the heated and cured epoxy resin and the electrode pad 11.
[0037]
As shown in FIG. 5C, the chip 2 is mounted on the circuit board 1 in the same manner as in the first embodiment.
[0038]
In such a flip-chip mounting method, the resin layer 3 can be easily formed on the circuit board 1 by applying an epoxy resin so as to be about 1 to 5 μm thinner than the thickness of the electrode pad 11 and then heating and curing. it can.
[0039]
Next, a method of forming different resin layers 3 and the third implementation mode will be described with reference to FIG. 6 as a fourth implementation of the invention. Figure 6 is an explanatory view showing a flip chip mounting method according to a fourth implementation mode of the present invention.
[0040]
As shown in FIG. 6A, an epoxy resin as a resin layer 3 is applied to the surface of the circuit board 1 having the electrode pads 11 thicker than the electrode pads 11 in a region including the electrode pads 11, and then heated and cured. To do. Then, as shown in FIG. 6B, the heated and cured epoxy resin is mechanically polished using a polishing machine (not shown) until it becomes substantially equal to the height of the electrode pad 11. Then, as shown in FIG. 6C, the film-like resin 4 used in the first embodiment is placed on the polished epoxy resin.
[0041]
As shown in FIG. 6D, the chip 2 is mounted on the circuit board 1 in the same manner as in the first embodiment.
[0042]
In such a flip chip mounting method, the heated and cured epoxy resin is polished until it is substantially equal to the height of the electrode pad 11, so that no excess epoxy resin is present on the upper surface of the electrode pad 11, and the epoxy resin is the chip 2. There is no possibility of entering between the protruding electrode 21 and the electrode pad 11 of the circuit board 1, and electrical connection between the protruding electrode 21 of the chip 2 and the electrode pad 11 of the circuit board 1 is efficiently performed.
[0043]
Next, other processing methods for the resin layer 3 provided on the circuit board 1 will be described with reference to FIG. 7 as a fifth implementation mode of the present invention. Figure 7 is an explanatory view showing a flip chip mounting method according to a fifth implementation mode of the present invention.
[0044]
As shown in FIGS. 7A and 7B, an epoxy resin is applied to the surface of the circuit board 1 having the electrode pads 11 as the resin layer 3 so as to be thicker than the electrode pads 11 in the region including the electrode pads 11. After that, the upper layer portion of the epoxy resin is removed with, for example, the squeegee 120 until the head portion of the electrode pad 11 is exposed. Further, after that, the surface of the electrode pad 11 is completely free of organic substances using, for example, a reduced pressure or atmospheric pressure type plasma cleaning device (not shown), a cleaning device using UV ozone (not shown), or the like. Perform surface cleaning to remove. By performing such surface cleaning and removing the organic matter on the electrode pad 11, electrical connection between the protruding electrode 21 and the electrode pad 11 can be efficiently performed. Next, the epoxy resin is heated and cured to form a resin layer 3 substantially equal to the height of the electrode pad.
[0045]
Then, as shown in FIG. 7C, the film-like resin 4 used in the first embodiment is placed on the polished epoxy resin.
[0046]
As shown in FIG. 7D, the chip 2 is mounted on the circuit board 1 in the same manner as in the first embodiment.
[0047]
In such a flip chip mounting method, the epoxy resin is applied to the surface of the circuit board 1 to be thicker than the electrode pad 11, and then the upper layer of the epoxy resin is removed until the head of the electrode pad 11 is exposed, and then heated and cured. Further, there is no possibility that excess epoxy resin enters between the protruding electrode 21 of the chip 2 and the electrode pad 11 of the circuit board 1, and electrical connection between the protruding electrode 21 of the chip 2 and the electrode pad 11 of the circuit board 1 is achieved. Done efficiently.
[0048]
【The invention's effect】
In the flip chip mounting method of claim 1 according to the above manner the present invention, a resin layer, Ru provided so as height and substantially equal to the electrode pad on the surface of the circuit board process, small and the film-like resin set Keru process on the electrode pads even without prior Symbol the film-like resin by projecting electrode presses the protruding electrode on the film-like resin so as to reach the electrode pads of the circuit board than including the step of bonding the electrode pad and the projecting electrode beating, the order of the film-like resin can be broken through facilitated by the protruding electrodes of the chip, the gap of the circuit board and the chip is large However, it was possible to provide a stable flip chip mounting method using the film-like resin.
[0050]
In the flip-chip mounting method according to claim 2, in the invention according to claim 1, the resin layer is formed by providing a film-like resin on the surface of the circuit board having the electrode pads, and then Since the resin-like resin is compressed to a thickness substantially equal to the electrode pad, the film-like resin provided on the surface of the circuit board having the electrode pad is approximately equal to the electrode pad. By providing it in a compressed manner, it is possible to easily form the resin layer on the surface of the circuit board.
[0051]
Further, in the flip chip mounting method according to claim 3, in the invention described in claim 1, wherein the resin layer. Thus a thermosetting, facilitates the resin layer on the circuit board There is an effect that it can be formed.
[0052]
Further, in the flip chip mounting method according to claim 4, in the invention according to claim 3, the resin layer is heated after a thermosetting resin is provided once thicker than the electrode pad. Since the thermosetting resin cured by heating is cured by polishing until the head of the electrode pad is exposed, the thermosetting resin heated and cured is By polishing until the height of the electrode pad is substantially equal, there is no excess epoxy resin, there is no excess resin layer on the upper surface of the electrode pad, and the resin layer is connected to the protruding electrode of the chip. There is no possibility of entering between the electrode pads of the circuit board, and the electrical connection between the protruding electrodes of the chip and the electrode pads of the circuit board is efficiently performed.
[0053]
In the flip-chip mounting method according to claim 5, in the invention according to claim 3, the resin layer is provided with a thermosetting resin once thicker than a thickness of the electrode pad, and the electrode pad Since the upper layer portion of the thermosetting resin is removed until the head portion of the resin is exposed, the resin layer is applied to the surface of the circuit board to be thicker than the electrode pad. Then, the upper layer portion of the resin layer is removed until the head of the electrode pad is exposed, and then heated and cured, so that the excess resin layer is formed on the protruding electrode of the chip and the electrode pad of the circuit board. possibility is eliminated that enters between the electrical connection between the electrode pads of the circuit substrate and the protrusion electrode that Sosu the effect that efficient performance.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing a flip chip mounting method according to a first embodiment of the present invention.
FIG. 2 is an explanatory view (top view) showing a flip chip mounting method according to the first embodiment of the present invention;
FIG. 3 is an explanatory view showing a flip chip mounting method according to a reference example of the present invention.
4 is an explanatory view showing a flip chip mounting method according to a second implementation embodiment of the present invention.
5 is an explanatory diagram showing a flip chip mounting method according to a third implementation mode of the present invention.
6 is an explanatory view showing a flip chip mounting method according to a fourth implementation mode of the present invention.
7 is an explanatory view showing a flip chip mounting method according to a fifth implementation mode of the present invention.
FIG. 8 is an explanatory view showing a flip chip mounting method according to a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Circuit board 2 Chip 3 Resin layer 4 Film-form resin 11 Electrode pad 21 Projection electrode 22 Electrode 31 Resin layer 32 Film-form resin

Claims (5)

チップの実装面に設けられた突起電極を、回路基板上の所定の位置に搭載して該回路基板の表面に設けられた電極パッドと電気的に接続させるフリップチップ実装方法において、
樹脂層を、前記回路基板の表面に前記電極パッドの高さと略等しくなるように設ける工程と、
少なくとも前記電極パッド上にフィルム状樹脂を設ける工程と、
前記突起電極が前記回路基板の前記電極パッドに到達するように前記突起電極を前記フィルム状樹脂に押圧することで該フィルム状樹脂を破って前記突起電極と前記電極パッドとを接合する工程を含むことを特徴とするフリップチップ実装方法。In the flip chip mounting method, the protruding electrode provided on the chip mounting surface is mounted at a predetermined position on the circuit board and electrically connected to the electrode pad provided on the surface of the circuit board.
And a resin layer, Ru provided so as height and substantially equal to the electrode pad on the surface of the circuit board process,
A step Keru set the film-like resin on the electrode pads even without low,
The process of the previous SL protruding electrodes bonding the circuit wherein the protruding electrodes so as to reach the electrode pad by pressing the film-like resin with the film-like resin broke with the protruding electrode electrode pads of the substrate flip chip mounting wherein a whatever child. 前記樹脂層は、フィルム状樹脂を前記電極パッドを有する回路基板表面に設けて後、該フィルム状樹脂を前記電極パッドと略等しい厚みとなるまで圧縮するようにして形成したことを特徴とする請求項１に記載のフリップチップ実装方法。The resin layer after providing a film-like resin to the circuit board surface with the electrode pad, characterized that you formed so as to compress the film-like resin until substantially equal thickness as the electrode pad The flip chip mounting method according to claim 1. 前記樹脂層は、熱硬化性であることを特徴とする請求項１に記載のフリップチップ実装方法。The flip chip mounting method according to claim 1, wherein the resin layer is thermosetting . 前記樹脂層は、熱硬化性の樹脂を前記電極パッドの厚みより一旦厚く設けた後加熱して硬化させ、該加熱し硬化させた熱硬化性の樹脂を前記電極パッドの頭部が露出するまで研磨することにより形成したことを特徴とする請求項３に記載のフリップチップ実装方法。The resin layer is provided with a thermosetting resin once thicker than the thickness of the electrode pad, and then heated and cured, and the heated and cured thermosetting resin is exposed until the head of the electrode pad is exposed. 4. The flip chip mounting method according to claim 3, wherein the flip chip mounting method is formed by polishing . 前記樹脂層は、熱硬化性の樹脂を前記電極パッドの厚みより一旦厚く設け、前記電極パッドの頭部が露出するまで熱硬化性の樹脂の上層部を除去して後、加熱し硬化させるようにして形成したことを特徴とする請求項３に記載のフリップチップ実装方法。The resin layer only once thicker set than a thermosetting resin thickness of the electrode pad, after removing the upper portion of the thermosetting resin to a head portion of the electrode pad is exposed, followed by heating to cure 4. The flip chip mounting method according to claim 3, wherein the flip chip mounting method is formed as described above.
JP2001156117A 2001-05-24 2001-05-24 Flip chip mounting method Expired - Fee Related JP3829649B2 (en)

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