JP4542842B2 - Interelectrode connection structure - Google Patents

Interelectrode connection structure Download PDF

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JP4542842B2
JP4542842B2 JP2004204760A JP2004204760A JP4542842B2 JP 4542842 B2 JP4542842 B2 JP 4542842B2 JP 2004204760 A JP2004204760 A JP 2004204760A JP 2004204760 A JP2004204760 A JP 2004204760A JP 4542842 B2 JP4542842 B2 JP 4542842B2
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elastic
filler
connection structure
conductive adhesive
rubber
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JP2006032412A (en
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武 佐野
秀章 大倉
寛史 小林
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Ricoh Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
    • H01L24/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L24/26—Layer connectors, e.g. plate connectors, solder or adhesive layers; Manufacturing methods related thereto
    • H01L24/28—Structure, shape, material or disposition of the layer connectors prior to the connecting process
    • H01L24/29—Structure, shape, material or disposition of the layer connectors prior to the connecting process of an individual layer connector
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • 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
    • H01L2224/26—Layer connectors, e.g. plate connectors, solder or adhesive layers; Manufacturing methods related thereto
    • H01L2224/28—Structure, shape, material or disposition of the layer connectors prior to the connecting process
    • H01L2224/29—Structure, shape, material or disposition of the layer connectors prior to the connecting process of an individual layer connector
    • H01L2224/29001—Core members of the layer connector
    • H01L2224/29099—Material
    • H01L2224/29198—Material with a principal constituent of the material being a combination of two or more materials in the form of a matrix with a filler, i.e. being a hybrid material, e.g. segmented structures, foams
    • H01L2224/29298—Fillers
    • H01L2224/29299—Base material
    • H01L2224/293—Base material with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof
    • 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
    • H01L2224/26—Layer connectors, e.g. plate connectors, solder or adhesive layers; Manufacturing methods related thereto
    • H01L2224/28—Structure, shape, material or disposition of the layer connectors prior to the connecting process
    • H01L2224/29—Structure, shape, material or disposition of the layer connectors prior to the connecting process of an individual layer connector
    • H01L2224/29001—Core members of the layer connector
    • H01L2224/29099—Material
    • H01L2224/29198—Material with a principal constituent of the material being a combination of two or more materials in the form of a matrix with a filler, i.e. being a hybrid material, e.g. segmented structures, foams
    • H01L2224/29298—Fillers
    • H01L2224/29299—Base material
    • H01L2224/2939—Base material with a principal constituent of the material being a polymer, e.g. polyester, phenolic based polymer, epoxy
    • 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
    • H01L2224/73—Means for bonding being of different types provided for in two or more of groups H01L2224/10, H01L2224/18, H01L2224/26, H01L2224/34, H01L2224/42, H01L2224/50, H01L2224/63, H01L2224/71
    • H01L2224/732—Location after the connecting process
    • H01L2224/73201—Location after the connecting process on the same surface
    • H01L2224/73203—Bump and layer connectors
    • H01L2224/73204—Bump and layer connectors the bump connector being embedded into the layer connector
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/10—Details of semiconductor or other solid state devices to be connected
    • H01L2924/11—Device type
    • H01L2924/14—Integrated circuits

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  • Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Electric Connection Of Electric Components To Printed Circuits (AREA)
  • Wire Bonding (AREA)
  • Conductive Materials (AREA)
  • Adhesives Or Adhesive Processes (AREA)

Description

本発明はプリント配線基板上に電子部品を電気的機械的に接続固定する際に使用する弾性導電接着剤の改良に関し、特に従来弾性率と導電率をバランス良く両立させることが困難であったために大きな接続部歪みに対応することができなかった弾性導電接着剤を改良した技術に関するものである。   The present invention relates to an improvement in an elastic conductive adhesive used when an electronic component is electrically and mechanically connected and fixed on a printed wiring board, and in particular, since it has been difficult to balance both the elastic modulus and the electric conductivity in a balanced manner. The present invention relates to a technique for improving an elastic conductive adhesive that could not cope with a large distortion of a connection portion.

ＢＧＡ、ＣＳＰ、ＦＣ等のようにエリアアレイ状に電極形成されたパッケージ品の実装基板への接合や、半導体部品の実装基板へのフリップチップ接合においては、実装基板との線膨張係数差に起因する熱ストレスに対する接合信頼性が問題となっている。
このような問題に対処するため、ＷＯ９８／５０９５０、特開平１０−２５６３０４号、及び特開２００３−１４２５２８には、夫々弾性を有した導電性接着剤を用いて実装基板と搭載部品の電極間を接合することにより、接合部にかかる熱ストレスを弾性変形により吸収緩和する技術が提案されている。
即ち、ＷＯ９８／５０９５０には、パッケージの外部接続端子であるバンプ電極を弾性体で構成し、パッケージとこれを実装するプリント配線基板との熱膨張係数差に起因して生じるストレスをバンプ電極の弾性変形によって吸収するようにした技術が開示されている。バンプ電極を構成する弾性体の好ましい弾性率は、０．００００１Ｇｐａ〜５Ｇｐａ、より好ましくは０．００１Ｇｐａ〜１Ｇｐａであるとされている。
また、特開平１０−２５６３０４号には、半導体集積回路チップの能動素子面に設けられた突起電極に、ゴム状弾性を有する導電性接着剤を塗布する工程と、絶縁基板上に設けられた基板電極に突起電極との位置を合わせて半導体集積回路チップを固着する工程と、半導体集積回路チップと基板電極の間隙に硬化収縮する特性を有する封止樹脂を注入する工程と、封止樹脂を硬化収縮し、前記導電性接着剤を介した突起電極と基板電極との電気的接続を行う工程とを有する半導体装置の製造方法が開示されている。そして、固着工程後のゴム状弾性を有する導電性接着剤のヤング率は１０ＭＰａ以下であり、硬化収縮する特性を有する封止封止樹脂の硬化収縮率が３％以上であるとされている。これによれば、ゴム状弾性を有する導電性接着剤の硬化後、冷却とともに半導体集積回路チップと絶縁基板との熱膨張率の差により導電性接着剤にせん断応力が加わっても、導電性接着剤がこのせん断応力を緩和するため、剥離や接着剤層の破壊を生じない。また、硬化収縮の大きな封止樹脂の採用により発生する縦方向の応力を導電性接着剤の樹脂成分が妨げることがなく、突起電極と基板電極が導電性接着剤の導電粒子を介して圧接され良好な電気的接続が得られる。
また、特開２００３−１４２５２８には、回路基板の少なくとも入出力端子電極上の接続部位に多孔質の樹脂フィルムが存在し、樹脂フィルムの接続部位に相当する厚さ方向の位置に貫通孔が設けられ、前記貫通孔に導電性接着剤が充填された回路基板とリペア方法及び実装構造体が開示されている。これによれば、基板の反りうねりに対し柔軟に対応でき、導電性接着剤が応力を緩和し素子や配線にダメ−ジを与えず、高生産に適し、高信頼性も確保された低荷重の熱圧着実装が可能になり、狭ピッチ及びエリア配列の高性能な接続が低コストで実現できる、とされている。 Due to the difference in coefficient of linear expansion from the mounting substrate, bonding of packaged products with electrodes formed in an area array like BGA, CSP, FC, etc. to the mounting substrate and flip chip bonding of semiconductor components to the mounting substrate Therefore, the reliability of bonding to thermal stress is a problem.
In order to cope with such a problem, WO98 / 50950, JP-A-10-256304, and JP-A-2003-142528 each use a conductive adhesive having elasticity to provide a gap between the mounting substrate and the electrodes of the mounted component. A technique has been proposed in which thermal stress applied to the joint is absorbed and relaxed by elastic deformation.
That is, in WO98 / 50950, a bump electrode which is an external connection terminal of a package is formed of an elastic body, and stress caused by a difference in thermal expansion coefficient between the package and a printed wiring board on which the package is mounted is applied to the elasticity of the bump electrode. A technique for absorbing by deformation is disclosed. A preferable elastic modulus of the elastic body constituting the bump electrode is 0.00001 Gpa to 5 Gpa, more preferably 0.001 Gpa to 1 Gpa.
Japanese Patent Application Laid-Open No. 10-256304 discloses a step of applying a conductive adhesive having rubber-like elasticity to a protruding electrode provided on an active element surface of a semiconductor integrated circuit chip, and a substrate provided on an insulating substrate. The step of fixing the semiconductor integrated circuit chip by aligning the protruding electrode with the electrode, the step of injecting a sealing resin having a characteristic of curing and shrinking into the gap between the semiconductor integrated circuit chip and the substrate electrode, and the curing of the sealing resin A method of manufacturing a semiconductor device is disclosed which includes a step of contracting and electrically connecting the protruding electrode and the substrate electrode via the conductive adhesive. The Young's modulus of the conductive adhesive having rubber-like elasticity after the fixing step is 10 MPa or less, and the curing shrinkage rate of the sealing sealing resin having the property of curing shrinkage is 3% or more. According to this, even after the curing of the conductive adhesive having rubbery elasticity, even if shear stress is applied to the conductive adhesive due to the difference in thermal expansion coefficient between the semiconductor integrated circuit chip and the insulating substrate together with cooling, the conductive adhesive Since the agent relaxes this shear stress, it does not cause peeling or destruction of the adhesive layer. In addition, the resin component of the conductive adhesive does not interfere with the longitudinal stress generated by the use of a sealing resin with large curing shrinkage, and the protruding electrode and the substrate electrode are pressed against each other through the conductive particles of the conductive adhesive. Good electrical connection is obtained.
Japanese Patent Application Laid-Open No. 2003-142528 has a porous resin film at least at a connection portion on the input / output terminal electrode of the circuit board, and a through hole is provided at a position in the thickness direction corresponding to the connection portion of the resin film. A circuit board in which the through hole is filled with a conductive adhesive, a repair method, and a mounting structure are disclosed. According to this, it can respond flexibly to the warping and waviness of the substrate, the conductive adhesive relieves stress, does not damage the elements and wiring, suitable for high production, low load that ensures high reliability It is said that high-temperature connection with a narrow pitch and area arrangement can be realized at low cost.

ところで、従来の弾性を持った導電体（導電性接着剤）としては、表面に導電層を形成した弾性体や球状あるいはフレーク状の導電性フィラーとゴム状弾性樹脂を混練した弾性体が提案されている。しかし、弾性変形時の表面導電層の剥がれ防止や、応力緩和機能向上のために低弾性率化するためには、金属フィラーの含有量を低減する必要があるが、フィラーを減らした分だけ電気抵抗を低抵抗化することができないという欠点があった。つまり、低弾性率化と低抵抗化は二律背反の関係にあり、機械的接続と電気的接続について高い接続信頼性を両立させることは困難であった。このため、低抵抗化を要求された場合は弾性率が高くなって熱ストレス緩和機能が低下してしまい、弾性導電接着剤及び弾性導電シートとしての適用範囲が制限されていた。
更に、電極間接続部をリペアするためには、接続部にせん断方向の力を加えた場合に電極表面に接着剤の残渣が残らないことが重要であるが、従来は残渣の残留を解消できなかったため、リペアによる再接合に際して支障があった。
ＷＯ９８／５０９５０ 特開平１０−２５６３０４号 特開２００３−１４２５２８ By the way, as a conventional elastic conductor (conductive adhesive), an elastic body in which a conductive layer is formed on the surface or an elastic body in which a spherical or flaky conductive filler and a rubber-like elastic resin are kneaded have been proposed. ing. However, in order to reduce the elastic modulus in order to prevent peeling of the surface conductive layer during elastic deformation and to improve the stress relaxation function, it is necessary to reduce the metal filler content. There is a drawback that the resistance cannot be reduced. That is, lowering the elastic modulus and lowering resistance are in a trade-off relationship, and it is difficult to achieve both high connection reliability for mechanical connection and electrical connection. For this reason, when low resistance is requested | required, an elasticity modulus became high and the thermal stress relaxation function fell, and the application range as an elastic conductive adhesive and an elastic conductive sheet was restrict | limited.
Furthermore, in order to repair the connection part between the electrodes, it is important that no adhesive residue remains on the electrode surface when a shearing force is applied to the connection part. As a result, there was a problem in rejoining by repair.
WO98 / 50950 JP 10-256304 A JP2003-142528

本発明は上記に鑑みてなされたものであり、電子部品実装工程での生産性を高く維持したまま、低弾性率化と低電気抵抗化とを両立した導電性接着剤を用いて、接続部での応力緩和性能に優れた接続を可能とする弾性導電接着剤及び電極間接続構造を提供するものである。   The present invention has been made in view of the above, and using a conductive adhesive that achieves both low elastic modulus and low electrical resistance while maintaining high productivity in the electronic component mounting process, the connecting portion It is intended to provide an elastic conductive adhesive and an interelectrode connection structure that enable connection with excellent stress relaxation performance.

上記課題を解決するため、請求項１の発明は、弾性導電接着剤を用いて２つの電極間を電気的機械的に接続する電極間接続構造であって、前記弾性導電接着剤は、ゴム状弾性樹脂に、多数の一軸方向に伸びた針形状導電性フィラーと、針形状導電性フィラーの径よりも直径が大きい球状フィラーを混在させた構成を有し、前記弾性導電接着剤に含まれる球状フィラーの一部が前記２つの電極間に直接接触した状態で接続されているとともに、前記２つの電極の内の一方は回路基板側の電極であり、他方の電極は電子部品側の電極であり、前記回路基板側の電極は表層を金にて構成した金電極であることを特徴とする。
請求項２の発明は、請求項１において、前記針形状導電性フィラーは、径１μｍ以下のウィスカの少なくとも最表面に金属被覆膜を形成した構成を備えていることを特徴とする。
請求項３の発明は、請求項１、又は２において、前記球状フィラーの直径は、５〜１００μｍであることを特徴とする。
請求項４の発明は、請求項１、２又は３において、前記球状フィラーは、少なくともその一部がゴム状弾性樹脂から構成されていることを特徴とする。
請求項５の発明は、請求項４において、前記球状フィラーの少なくとも一部を構成するゴム状弾性樹脂の弾性率は、ゴム状弾性樹脂に針形状導電性フィラーを混練した導電性接着剤よりも低弾性率であることを特徴とする。
請求項６の発明は、請求項１、２、３、４又は５において、前記球状フィラーの全体、又は少なくともその一部が導電性を有していることを特徴とする。
請求項７の発明は、請求項６において、前記球状フィラーは、非導電性コア材と、非導電性コア材の表面に形成された金属被覆層と、から構成されていることを特徴とする。
請求項８の発明は、請求項７において、前記非導電性コア材はゴム状弾性樹脂からなり、前記金属被覆層は非導電性コア材の表面に付着した金属フィラーからなることを特徴とする。 In order to solve the above problems, the invention of claim 1 is an inter-electrode connection structure in which two electrodes are electrically and mechanically connected using an elastic conductive adhesive, and the elastic conductive adhesive is rubber-like. The elastic resin has a configuration in which a large number of uniaxially extending needle-shaped conductive fillers and a spherical filler having a diameter larger than the diameter of the needle-shaped conductive filler are mixed, and the spherical shape contained in the elastic conductive adhesive A part of the filler is connected in a state of direct contact between the two electrodes, one of the two electrodes is an electrode on the circuit board side, and the other electrode is an electrode on the electronic component side The electrode on the circuit board side is a gold electrode having a surface layer made of gold .
According to a second aspect of the present invention, in the first aspect, the needle-shaped conductive filler has a configuration in which a metal coating film is formed on at least the outermost surface of a whisker having a diameter of 1 μm or less.
A third aspect of the present invention is characterized in that, in the first or second aspect, the spherical filler has a diameter of 5 to 100 μm.
According to a fourth aspect of the present invention, in the first, second, or third aspect, at least a part of the spherical filler is made of a rubber-like elastic resin.
According to a fifth aspect of the present invention, in the fourth aspect, the elastic modulus of the rubber-like elastic resin constituting at least a part of the spherical filler is higher than that of the conductive adhesive obtained by kneading the needle-like conductive filler in the rubber-like elastic resin. It has a low elastic modulus.
A sixth aspect of the present invention is characterized in that in the first, second, third, fourth, or fifth aspect, the whole or at least a part of the spherical filler has conductivity.
The invention of claim 7 is characterized in that, in claim 6, the spherical filler is composed of a non-conductive core material and a metal coating layer formed on the surface of the non-conductive core material. .
The invention of claim 8 is characterized in that, in claim 7, the non-conductive core material is made of a rubber-like elastic resin, and the metal coating layer is made of a metal filler attached to the surface of the non-conductive core material. .

請求項９の発明は、請求項７において、前記非導電性コア材は、ゴム状弾性樹脂からなり、前記金属被覆層は、非導電性コア材の表層に付着した金属フィラーと、金属フィラーを付着させた非導電性コア材表面に無電解メッキにて被覆形成した金属導電膜と、からなることを特徴とする。
請求項１０の発明は、請求項７、８、又は９において、前記球状フィラー表面の金属被覆層には、段差が０．１〜１μｍの範囲の凹凸が形成されていることを特徴とする。
請求項１１の発明は、請求項７、８、又は９において、前記金属被覆層表面に、直径１００ｎｍ以下の金属微粒子が付着していることを特徴とする。
請求項１２の発明は、請求項１１の弾性導電接着剤を用いて２つの電極間を電気的機械的に接続する構造において、球状フィラー表面に対して金属微粒子が融着するとともに、金属微粒子の一部が針形状導電性接着剤とも融着していることを特徴とする。
請求項１３の発明は、請求項１乃至１２において、前記回路基板側の金電極と、前記弾性導電接着剤との接続部にせん断方向の力を加えたときに、前記弾性導電接着剤が前記回路基板側の金電極表面で残渣なく剥離するように構成したことを特徴とする。
請求項１４の発明は、請求項１、１２又は１３において、前記弾性導電接着剤による電極間の接続部周辺をゴム状弾性樹脂にて封止したことを特徴とする。 The invention according to claim 9 is the invention according to claim 7, wherein the non-conductive core material is made of a rubber-like elastic resin, and the metal coating layer includes a metal filler attached to a surface layer of the non-conductive core material, and a metal filler. And a metal conductive film formed by electroless plating on the surface of the non-conductive core material adhered.
The invention of claim 10, in claim 7, 8 or 9, and the metallization layer of the spherical filler surface is characterized in that a step is formed unevenness in the range of 0.1 to 1 [mu] m.
The invention of claim 11 is characterized in that, in claim 7, 8, or 9, metal fine particles having a diameter of 100 nm or less are adhered to the surface of the metal coating layer .
Invention 請 Motomeko 12, in electrically and mechanically connected to the structure between two electrodes using an elastic conductive adhesive agent according to claim 11, with the metal fine particles are fused against the spherical filler surface, fine metal particles Is partly fused with the needle-shaped conductive adhesive .
Invention 請 Motomeko 13, in claims 1 to 12, and the gold electrode of the circuit board side, when a force is applied in the shear direction to the connecting portion between the elastic conductive adhesive, wherein the elastic conductive adhesive The circuit board side gold electrode surface is configured to be peeled off without residue.
The invention of claim 14, in claim 1, 12 or 13, the connecting portion near the electrodes due to the elastic conductive adhesive, characterized in that sealed with rubber-like elastic resin.

本発明によれば、ゴム状弾性樹脂に針形状導電性フィラーを分散させた弾性導電接着剤中に、更に球状フィラーを含有しているので、球状フィラーの直径が電極間の間隔を実質的に確定する要素となり、実装工程の生産性を落とすことなく接続厚を制御することができ、優れた応力緩和接続が可能となる。なお、球状フィラーといっても、厳密な意味の球状でなくてもよい。
本発明によれば、径１μｍ以下の微細ウィスカに銀等を金属被覆しているので、微細接続に対応できる弾性導電接着剤を得ることができる。
本発明によれば、球状フィラーの直径を５〜１００μｍとすることで、接続ピッチに対応した接続厚を制御できる。
本発明によれば、球状フィラーをゴム状弾性樹脂することで、接続部の変形能力が高められ、優れた応力緩和性能を得られる。特に、ゴム状弾性樹脂に針形状導電性フィラーを混練した接着剤よりも低弾性としたので、さらに応力緩和性能が高まる。
本発明によれば、球状フィラーに導電性を持たせることで、電極間及び針形状導電性フィラーとの接触により接続抵抗を低減できる。
本発明によれば、球状フィラーの一部が接続対象物としての２つの電極間に直接接触していることから、球状フィラー径に準じた接続厚を確保することができる。
本発明によれば、金属フィラー表面にて金属粒子が融着していることから、接続抵抗を低減できる。
本発明によれば、基板側電極表面を金としているため、接続部にせん断方向の力を加えることで基板側電極界面での剥離が可能となり、リペア（剥離、再接合）を容易にできる。
本発明によれば、接合部周辺をゴム状弾性樹脂にて封止することで、弾性導電接着剤の応力緩和機能を損なうことなく接続部の信頼性を向上できる。

According to the present invention, since the spherical conductive filler is further contained in the elastic conductive adhesive in which the needle-shaped conductive filler is dispersed in the rubber-like elastic resin, the diameter of the spherical filler substantially reduces the interval between the electrodes. It becomes a determinative factor, and the connection thickness can be controlled without reducing the productivity of the mounting process, and an excellent stress relaxation connection is possible. Note that the spherical filler does not have to be spherical in the strict sense.
According to the present invention, since fine whiskers having a diameter of 1 μm or less are coated with silver or the like, an elastic conductive adhesive that can cope with fine connection can be obtained.
According to the present invention, the connection thickness corresponding to the connection pitch can be controlled by setting the diameter of the spherical filler to 5 to 100 μm.
According to the present invention, the spherical filler is made of a rubber-like elastic resin, so that the deformability of the connecting portion is enhanced, and excellent stress relaxation performance can be obtained. Particularly, since the elasticity is lower than that of an adhesive obtained by kneading a needle-shaped conductive filler in a rubber-like elastic resin, the stress relaxation performance is further enhanced.
According to the present invention, by imparting conductivity to the spherical filler, the connection resistance can be reduced by contact between the electrodes and with the needle-shaped conductive filler.
According to the present invention, since a part of the spherical filler is in direct contact between the two electrodes as the connection object, a connection thickness according to the spherical filler diameter can be ensured.
According to the present invention, since the metal particles are fused on the surface of the metal filler, the connection resistance can be reduced.
According to the present invention, since the substrate-side electrode surface is gold, peeling at the substrate-side electrode interface is possible by applying a shearing direction force to the connecting portion, and repair (peeling, rejoining) can be facilitated.
According to the present invention, the reliability of the connection portion can be improved without impairing the stress relaxation function of the elastic conductive adhesive by sealing the periphery of the joint portion with the rubber-like elastic resin.

以下、本発明を図面に示した実施の形態により詳細に説明する。
図１は、本発明の参考実施形態に係る弾性導電接着剤と、電極間接続構造（電気回路構造物）の構成を説明する断面図である。
この電極間接続構造（電気回路構造物）１は、絶縁基板３上に電極４を形成して成る電気回路基板（実装基板）２と、電極１１を備えた電子部品１０の、各電極４、１１間を弾性導電接着剤２０を用いて電気的機械的に接続した構成を備えている。弾性導電接着剤２０は、ゴム状弾性樹脂２１に微細な針形状導電性フィラー２２と、球状フィラー３０を混練した構成を備えている。即ち、本発明の参考実施形態に係る弾性導電接着剤２０は、ゴム状弾性樹脂２１に、多数の一軸方向に伸びた針形状導電性フィラー２２と、針形状導電性フィラーの径よりも直径が大きい球状フィラー３０を混在させた構成が特徴的である。
本発明者は、上記の如き構成を備えた弾性導電接着剤２０の硬化物が、ゴム状弾性樹脂２１の低弾性率特性を損なわずに低抵抗な接続材料となることを見出し、この知見に基づいて本電極間接続構造の発明をなすに至ったものである。
本参考実施形態に係る弾性導電接着剤２０にあっては、ゴム状弾性樹脂２１中への針形状導電フィラー２２の充填量が、一般的なフレーク状導電フィラーに比べて低充填量であっても十分に実用に耐え得る低抵抗化を実現できる。これは、針形状導電フィラー２２のアスペクト比が大きく、３次元的な網目構造を有して接触状態を形成することができるためであり、ゴム状弾性樹脂２１の弾性変形能力を阻害せず、安定した導通抵抗を実現できる。
このゴム状弾性樹脂２１に針形状導電性フィラー２２を均一に混練した弾性導電接着剤２０を用いて、電気回路基板２上へ電子部品１０を実装することにより、熱膨張差等により発生する接続部応力を接続部（弾性導電接着剤２０）が変形することにより緩和することができ、接続信頼性を大幅に向上できる。 Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.
Figure 1 is a cross-sectional view illustrating the configuration of the elastic conductive adhesive according to a reference embodiment of the present invention, conductive interelectrode connection structure (electric circuit structure).
This inter-electrode connection structure (electric circuit structure) 1 includes an electric circuit board (mounting board) 2 formed by forming an electrode 4 on an insulating substrate 3, and each electrode 4 of an electronic component 10 including an electrode 11, 11 is electrically and mechanically connected using an elastic conductive adhesive 20. The elastic conductive adhesive 20 has a configuration in which a fine needle-shaped conductive filler 22 and a spherical filler 30 are kneaded with a rubber-like elastic resin 21. That is, the elastic conductive adhesive 20 according to the reference embodiment of the present invention has a rubber-like elastic resin 21 with a needle-shaped conductive filler 22 extending in a uniaxial direction and a diameter larger than the diameter of the needle-shaped conductive filler. A configuration in which large spherical fillers 30 are mixed is characteristic.
The present inventor has found that the cured product of the elastic conductive adhesive 20 having the above-described configuration becomes a low-resistance connection material without impairing the low elastic modulus characteristics of the rubber-like elastic resin 21. The present invention has led to the invention of the interelectrode connection structure .
In the elastic conductive adhesive 20 according to the present embodiment, the filling amount of the needle-shaped conductive filler 22 in the rubber-like elastic resin 21 is lower than that of a general flaky conductive filler. However, it is possible to realize a low resistance enough to withstand practical use. This is because the needle-shaped conductive filler 22 has a large aspect ratio and can form a contact state with a three-dimensional network structure, and does not hinder the elastic deformation ability of the rubber-like elastic resin 21, A stable conduction resistance can be realized.
By using the elastic conductive adhesive 20 in which the needle-shaped conductive filler 22 is uniformly kneaded with the rubber-like elastic resin 21, the electronic component 10 is mounted on the electric circuit board 2, thereby causing a connection caused by a thermal expansion difference or the like. The partial stress can be relaxed by the deformation of the connecting portion (elastic conductive adhesive 20), and the connection reliability can be greatly improved.

フィラー２２の充填比率が大きいために弾性率が低くなっている従来の弾性導電接着剤により、接続部の応力緩和特性を向上するためには、接続厚を厚くすることが有効である。また、一般的に電子部品のマウントに際しては、実装装置の生産性向上の為に、回路基板に対する電子部品の加圧力を制御しつつ電子部品を回路基板に押し付ける方式が採用されているが、この方式によりマウントする際に回路基板上の電極と電子部品の電極との間の弾性導電接着剤の接続厚を制御せんとすると、実装工程の生産性低下を招いてしまう。
本参考実施形態においては、弾性導電接着剤２０中に、電極間の接続厚（弾性導電接着剤厚）を画一的にコントロールするための球状フィラー３０を適量均一に混練している。このように所定の剛性を有し且つ均一直径を有した球状フィラー３０を均一に含有したことで、回路基板２上にスクリーン印刷等の方法により弾性導電接着剤２０を供給した後、電子部品１０をマウントするに際し、加圧力制御あるいは電子部品を基板に押しつける方式を採用したとしても、球状フィラーの直径を超えて接続厚を更に薄くすることはできない。つまり、この弾性導電接着剤２０を用いれば、球状フィラー径に準ずる接続厚を確保することができるため、実装工程での生産性低下を招くことなく、接続部での大きな変形に耐えられる優れた応力緩和接続が可能となる。球状フィラー３０が両電極４、１１間に挟まれた構造（両電極と直接接触した構造）で接続厚をコントロールしていることから、回路基板に反り等が存在していても少なくとも一部の球状フィラーは電極と接触している状態を確保できる。
この球状フィラー３０の直径は、針形状導電フィラー２２の径よりも大きく、球状フィラー３０の直径としては５〜１００μｍのものを用いることができる。球状フィラー３０の径が小さすぎると接続部での応力緩和性能が小さくなる。一方、球状フィラー径が大きすぎると、スクリーン印刷等による供給性能等が悪くなって狭ピッチ接続が困難になってしまうため、好ましくは１０〜６０μｍであることが望ましい。
弾性導電接着剤２０の導電性に関しては、基本的には針形状導電フィラー２２同志の接触により低抵抗接続が可能となるが、球状フィラー３０にも導電性を持たせると、球状フィラーによる電極間接続と、球状フィラーと針形状導電フィラーとの接触により更なる低抵抗接続が可能となる。 In order to improve the stress relaxation characteristics of the connection portion with a conventional elastic conductive adhesive having a low elastic modulus due to a large filling ratio of the filler 22, it is effective to increase the connection thickness. In general, when mounting an electronic component, a method of pressing the electronic component against the circuit board while controlling the pressure of the electronic component against the circuit board is employed to improve the productivity of the mounting apparatus. If the connection thickness of the elastic conductive adhesive between the electrode on the circuit board and the electrode of the electronic component is controlled when mounting by the method, the productivity of the mounting process is reduced.
In the present embodiment , an appropriate amount of spherical filler 30 for uniformly controlling the connection thickness between electrodes (elastic conductive adhesive thickness) is uniformly kneaded in the elastic conductive adhesive 20. Since the spherical filler 30 having a predetermined rigidity and a uniform diameter is uniformly contained in this way, after the elastic conductive adhesive 20 is supplied onto the circuit board 2 by a method such as screen printing, the electronic component 10 Even when a pressure control or a method of pressing an electronic component against the substrate is adopted when mounting the connector, the connection thickness cannot be further reduced beyond the diameter of the spherical filler. In other words, if this elastic conductive adhesive 20 is used, it is possible to secure a connection thickness in accordance with the spherical filler diameter, so that it can withstand a large deformation in the connection portion without causing a decrease in productivity in the mounting process. Stress relaxation connection is possible. Since the connection thickness is controlled by a structure in which the spherical filler 30 is sandwiched between the electrodes 4 and 11 (a structure in direct contact with both electrodes), at least a part of the circuit board is warped. The spherical filler can ensure a state in contact with the electrode.
The diameter of the spherical filler 30 is larger than the diameter of the needle-shaped conductive filler 22, and the diameter of the spherical filler 30 can be 5 to 100 μm. When the diameter of the spherical filler 30 is too small, the stress relaxation performance at the connecting portion is reduced. On the other hand, if the spherical filler diameter is too large, the supply performance by screen printing or the like deteriorates and it becomes difficult to make a narrow pitch connection, and thus it is preferably 10 to 60 μm.
Regarding the conductivity of the elastic conductive adhesive 20, a low resistance connection is basically possible by contact between the needle-shaped conductive fillers 22, but if the spherical filler 30 is also made conductive, the electrodes between the spherical fillers can be connected. Further low resistance connection is possible by connection and contact between the spherical filler and the needle-shaped conductive filler.

球状フィラーは、全体を導電性材料にて構成してもよいが、非導電性コア材の表面の一部又は全部に金属被覆層を形成した構成とするのが好ましい。球状フィラーの構成を、非導電性コア材と金属被覆層から構成することにより、球状フィラーのコア材としてスチレン等のポリマー系を活用することができ、粒子径の均一化が容易になるとともに、硬化前の弾性導電接着剤中での沈殿等が発生しにくくなり、均一分散性を向上できることから接続部品質を安定化できる。
次に、球状フィラー３０の表層部に金属被覆層を形成することにより導電性を付与するに当たり、金属被覆層の表層に０．１〜１μｍの凹凸を均一に形成するのが好ましい。この凹凸は無電解めっき等により核成長させるプロセスにて形成可能である。この凹凸を形成することで針形状導電性フィラー２２との接触性及び電極との接触性が向上し、接続抵抗を低減できる効果を発揮できる。
針形状導電性フィラー２２としては、そのコア材として微細でアスペクト比の大きいウィスカを用い、その表層に金属たとえば銀（Ａｇ）を被覆することにより、低コストの針形状導電性フィラーを得ることができる。コア材としてのウィスカにＡｇを被覆する方法としては無電解めっき等が可能である。 The spherical filler may be entirely composed of a conductive material, but preferably has a configuration in which a metal coating layer is formed on part or all of the surface of the non-conductive core material. By configuring the spherical filler from a non-conductive core material and a metal coating layer, it is possible to utilize a polymer system such as styrene as the core material of the spherical filler, making it easy to make the particle diameter uniform, Precipitation or the like in the elastic conductive adhesive before curing hardly occurs, and uniform dispersibility can be improved, so that the quality of the connection portion can be stabilized.
Next, in order to impart conductivity by forming a metal coating layer on the surface layer portion of the spherical filler 30, it is preferable to uniformly form irregularities of 0.1 to 1 μm on the surface layer of the metal coating layer. Such irregularities can be formed by a process of growing nuclei by electroless plating or the like. By forming this unevenness, the contact with the needle-shaped conductive filler 22 and the contact with the electrode are improved, and the effect of reducing the connection resistance can be exhibited.
As the needle-shaped conductive filler 22, a low-cost needle-shaped conductive filler can be obtained by using a fine whisker having a large aspect ratio as the core material and coating the surface layer with metal such as silver (Ag). it can. As a method of coating Ag on the whisker as the core material, electroless plating or the like is possible.

次に、図２は本発明の参考実施形態に係る弾性導電接着剤を用いた電極間の接続構造におけるせん断歪みと抵抗特性との関係を示すグラフである。
この実施形態に使用した弾性導電接着剤２０は、ゴム状弾性樹脂２１の代表格であるシリコーン樹脂に、針形状導電フィラー２２と球状フィラー３０を含有させ、２０１２サイズの電子部品を回路基板上に接続固定した。今回使用したシリコーン樹脂としては加熱硬化型でゴム硬度（ＪＩＳ Ａ）９のものを使用し、針形状導電フィラー２２としては無機化合物ウィスカにＡｇめっきを施したもので、フィラー径約０．５μｍ、フィラー長約２０μｍのものである。また、球状フィラー３０としては、５０μｍ径のポリマー粒子の表面にＡｇ被覆したものを用いた。
上記構成において、針形状導電フィラー２２と球状フィラー３０を夫々分散性良く混練することにより、比抵抗：８Ｅ−４（Ω・ｃｍ）を得た。
図２は、実装後の機能評価を示しており、２０１２サイズの電子部品に対して、水平方向に力を加えて接続部に対してせん断歪を加え、そのときの抵抗変動を計測した結果を示している。ここで、せん断歪とは接続厚に対する水平方向の変位量を示し、せん断歪＝水平変位／接続厚として表す。
本接続構造においては、せん断歪１．５以上までは接続部が破壊することなく、安定した接続特性を有している。これは、本実施例での接続厚：５０μｍに対しては７５μｍ以上の水平方向変位が可能であることを示している。 Next, FIG. 2 is a graph showing the relationship between the shear strain and the resistance characteristics in the connection structure between the electrodes using the elastic conductive adhesive according to the reference embodiment of the present invention.
The elastic conductive adhesive 20 used in this embodiment contains a needle-shaped conductive filler 22 and a spherical filler 30 in a silicone resin, which is a typical rubber-like elastic resin 21, and a 2012-size electronic component is placed on a circuit board. Connection fixed. The silicone resin used this time is a thermosetting rubber rubber (JIS A) 9 and the needle-shaped conductive filler 22 is an inorganic compound whisker with Ag plating. The filler diameter is about 0.5 μm, The filler length is about 20 μm. Further, as the spherical filler 30, a polymer particle having a diameter of 50 μm coated with Ag was used.
In the above configuration, the specific resistance: 8E-4 (Ω · cm) was obtained by kneading the needle-shaped conductive filler 22 and the spherical filler 30 with good dispersibility.
FIG. 2 shows the functional evaluation after mounting. For a 2012 size electronic component, a force is applied in the horizontal direction to apply a shear strain to the connecting portion, and the result of measuring the resistance variation at that time is shown. Show. Here, the shear strain indicates the amount of displacement in the horizontal direction with respect to the connection thickness, and is expressed as shear strain = horizontal displacement / connection thickness.
In this connection structure, the connection portion does not break up to a shear strain of 1.5 or more and has stable connection characteristics. This indicates that a horizontal displacement of 75 μm or more is possible for a connection thickness of 50 μm in this example.

次に、図３は本発明の他の参考実施形態に係る電極間接続構造を示す断面図である。
本実施形態の特徴的な構成の一つは、球状フィラー３０がゴム状弾性樹脂（ゴムと同等の弾性を有したシリコーン樹脂等の樹脂材料）から構成されている点である。また、他の特徴的な構成は、ゴム状弾性樹脂から成る球状フィラー３０の弾性率が、ゴム状弾性樹脂２１に針形状導電性フィラー２２を混練した導電性接着剤よりも低弾性率である点にある。
即ち、まず、本実施形態では、球状フィラー３０の構成材料として、ゴム状弾性樹脂を用いている。ゴム状弾性樹脂を用いることにより、弾性導電接着剤１の歪に対して球状フィラー３０も追従して変形することができ、接続部での応力緩和性能が更に向上する。また、更にゴム状弾性樹脂２１と針形状導電フィラー２２を混練した弾性導電接着剤の硬化後の弾性率より、球状フィラー２２の弾性率を低くすることにより、全く抵抗なく弾性導電接着剤１が変形できるようにすることができる。ここで、弾性導電接着剤はゴム状弾性樹脂２１に針形状導電性フィラー２２を混練した構成を有していることから、ゴム状弾性樹脂２１単体の場合よりも見掛け上の弾性率は高くなる。一方、球状フィラー３０として用いるゴム状弾性樹脂は単体で用いることも可能であり、ゴム状弾性樹脂２１と同一のゴム状弾性樹脂を用いても大きな変形に追従できる。また、充填する球状フィラー表面を混練前にプラズマ表面処理などの乾式処理及び薬液などによる湿式表面処理により、表面を活性化しておくと、ゴム状弾性樹脂２１や針形状導電性フィラー２２との接着性を向上できる。 Next, FIG. 3 is a cross-sectional view showing an interelectrode connection structure according to another reference embodiment of the present invention.
One of the characteristic configurations of the present embodiment is that the spherical filler 30 is made of rubber-like elastic resin (resin material such as silicone resin having elasticity equivalent to rubber). Another characteristic configuration is that the elastic modulus of the spherical filler 30 made of rubber-like elastic resin is lower than that of the conductive adhesive obtained by kneading the needle-like conductive filler 22 into the rubber-like elastic resin 21. In the point.
That is, first, in this embodiment, a rubber-like elastic resin is used as a constituent material of the spherical filler 30. By using the rubber-like elastic resin, the spherical filler 30 can also be deformed following the strain of the elastic conductive adhesive 1, and the stress relaxation performance at the connection portion is further improved. Further, by reducing the elastic modulus of the spherical filler 22 from the elastic modulus after curing of the elastic conductive adhesive in which the rubber-like elastic resin 21 and the needle-shaped conductive filler 22 are kneaded, the elastic conductive adhesive 1 has no resistance at all. It can be made deformable. Here, since the elastic conductive adhesive has a configuration in which the needle-shaped conductive filler 22 is kneaded with the rubber-like elastic resin 21, the apparent elastic modulus is higher than that of the rubber-like elastic resin 21 alone. . On the other hand, the rubber-like elastic resin used as the spherical filler 30 can be used alone, and can follow a large deformation even when the same rubber-like elastic resin as the rubber-like elastic resin 21 is used. If the surface of the spherical filler to be filled is activated by dry treatment such as plasma surface treatment and wet surface treatment with a chemical solution before kneading, adhesion to the rubber-like elastic resin 21 or the needle-shaped conductive filler 22 is achieved. Can be improved.

次に、図４（ａ）及び（ｂ）は夫々本発明の他の参考実施形態に係る球状フィラーの説明図である。
図４（ａ）の球状フィラー３０は、ゴム状弾性樹脂から成る非導電性コア材３１と、非導電性コア材３１の表面に付着した金属フィラー３２ａからなる金属被覆層３２と、から成る。
即ち、この実施形態に係る球状フィラー３０は、ゴム状弾性樹脂から成る非導電性コア材３１の表層部に形成した金属被覆膜３２によって導電性を付与した構成を備えている。ここでは、ゴム状弾性樹脂の代表格であるシリコーン樹脂をコア粒子として製作した例を示す。そしてコア材３１の表面に金属微粒子である金属フィラー３２ａを機械的な力等を利用して一部が露出するように埋め込むことによって金属被腹膜３２を形成している。なお、非導電性コア材３１（コア材粒子）は３０μｍ径、金属フィラー（銀微粒子）は１μｍ径として形成した。銀微粒子から成る金属フィラー３２ａは、コア材３１の表面全面において連続的な接触が得られていなくても、弾性導電接着剤中の針形状導電性フィラー２２との接触を確保できることから接続抵抗を低減可能である。
次に、図４（ｂ）の球状フィラー３０は、ゴム状弾性樹脂から成る非導電性コア材３１と、非導電性コア材３１の表面に付着した金属フィラー３２ａと、金属フィラー３２ａを付着させた非導電性コア材表面に無電解メッキにて被覆形成した金属導電膜３２ｂと、からなる。
図４（ｂ）の球状フィラー３０は、コア材３１の表面層に金属微粒子から成る金属フィラー３２ａを、夫々の一部が露出するように埋め込んだ後、無電解めっきにより表層部に全面を被覆できる金属導電膜３２ｂを形成している。このように金属微粒子３２ａをコア材３１の表層部に事前に形成していることにより、無電解めっきによる導電被覆の困難なシリコーン粒子に対しても、無電解めっきによるめっき成長性が安定させることができ、導電性を更に高めることができる。 Next, FIGS. 4A and 4B are explanatory views of spherical fillers according to other reference embodiments of the present invention, respectively.
The spherical filler 30 in FIG. 4A includes a non-conductive core material 31 made of a rubber-like elastic resin, and a metal coating layer 32 made of a metal filler 32 a attached to the surface of the non-conductive core material 31.
That is, the spherical filler 30 according to this embodiment has a configuration in which conductivity is imparted by the metal coating film 32 formed on the surface layer portion of the non-conductive core material 31 made of rubber-like elastic resin. Here, an example is shown in which a silicone resin, which is a representative rubber-like elastic resin, is manufactured as a core particle. Then, a metal peritoneum 32 is formed by embedding a metal filler 32a, which is a metal fine particle, on the surface of the core material 31 so as to be partially exposed using mechanical force or the like. The non-conductive core material 31 (core material particles) was formed with a diameter of 30 μm, and the metal filler (silver fine particles) was formed with a diameter of 1 μm. Since the metal filler 32a made of silver fine particles can ensure contact with the needle-shaped conductive filler 22 in the elastic conductive adhesive even if continuous contact is not obtained over the entire surface of the core material 31, the connection resistance is reduced. It can be reduced.
Next, the spherical filler 30 in FIG. 4B has a non-conductive core material 31 made of rubber-like elastic resin, a metal filler 32a attached to the surface of the non-conductive core material 31, and a metal filler 32a. And a metal conductive film 32b formed by electroless plating on the surface of the nonconductive core material.
In the spherical filler 30 in FIG. 4B, a metal filler 32a composed of metal fine particles is embedded in the surface layer of the core material 31 so that a part of each is exposed, and then the entire surface layer portion is covered by electroless plating. The metal conductive film 32b that can be formed is formed. By forming the metal fine particles 32a in advance on the surface layer portion of the core material 31 in this way, the plating growth by electroless plating can be stabilized even for silicone particles that are difficult to be conductively coated by electroless plating. And the conductivity can be further increased.

次に、図５は本発明の他の参考実施形態に係る弾性導電接着剤の要部構成を示す拡大図である。
この実施形態に係る弾性導電接着剤１は、球状フィラー３０を構成する金属被覆層３２の表面に、直径１００ｎｍ以下の金属微粒子３３が付着している構成が特徴的である。
更に、他の特徴は、球状フィラー３０の表面にて金属微粒子３３が融着するとともに、その一部が針形状導電性フィラー２２とも融着している点にある。
即ち、本実施形態における１００ｎｍ以下の直径を持つ金属微粒子３３は、粒子表面の活性力が高いため低温で融着する特性を持っている。ここでは、この金属微粒子３３を導電層を有する球状フィラー３０の表面に形成した構造を持っている。この球状フィラー３０を弾性導電接着剤中に分散させ、電子部品等を基板上に接続することで電気回路構造物を製作できる。
次に具体的実施例を示す。
金属微粒子３３として平均粒径１０ｎｍの銀粒子を含む銀ナノペーストを球状フィラー３０と混練し、銀ナノペースト中の溶媒を揮発させることで球状フィラー（球状粒子）３０の表面に金属微粒子３３を分散付着させた。この球状フィラー３０をゴム状弾性樹脂２１、針形状導電性フィラー２２と混練した。この弾性導電接着剤１を用いて、回路基板２上に電子部品１０を接続するに際し、加熱硬化させる過程において、銀粒子３３は球状フィラー表面に融着する。このとき、球状フィラー表面に銀粒子から成る凹凸を形成することができるので、針形状導電性フィラー２２との接触性が向上できるとともに、部分的には銀粒子３３は針形状導電性フィラーとも接合できており接続抵抗の低減が図れた。
接続抵抗としては、以下の結果を得た。
金属微粒子なし ２５ｍΩ
金属微粒子あり １５ｍΩ Next, FIG. 5 is an enlarged view showing a main configuration of an elastic conductive adhesive according to another reference embodiment of the present invention.
The elastic conductive adhesive 1 according to this embodiment is characterized in that metal fine particles 33 having a diameter of 100 nm or less are attached to the surface of the metal coating layer 32 constituting the spherical filler 30.
Further, another feature is that the metal fine particles 33 are fused on the surface of the spherical filler 30 and a part thereof is also fused to the needle-shaped conductive filler 22.
That is, the metal fine particles 33 having a diameter of 100 nm or less in the present embodiment have a property of fusing at a low temperature because of the high activity of the particle surface. Here, the metal fine particles 33 have a structure formed on the surface of a spherical filler 30 having a conductive layer. An electrical circuit structure can be manufactured by dispersing the spherical filler 30 in an elastic conductive adhesive and connecting an electronic component or the like on the substrate.
Next, specific examples will be shown.
A silver nanopaste containing silver particles having an average particle diameter of 10 nm is kneaded with the spherical filler 30 as the metal fine particles 33 and the metal fine particles 33 are dispersed on the surface of the spherical filler (spherical particles) 30 by volatilizing the solvent in the silver nanopaste. Attached. The spherical filler 30 was kneaded with the rubber-like elastic resin 21 and the needle-shaped conductive filler 22. When the electronic component 10 is connected to the circuit board 2 using the elastic conductive adhesive 1, the silver particles 33 are fused to the spherical filler surface in the process of heat curing. At this time, since the irregularities made of silver particles can be formed on the spherical filler surface, the contact with the needle-shaped conductive filler 22 can be improved, and the silver particles 33 are also partially bonded to the needle-shaped conductive filler. The connection resistance can be reduced.
The following results were obtained as connection resistance.
Without metal fine particles 25mΩ
With fine metal particles 15mΩ

次に、図６は本発明の実施形態に係る電極間接続構造（回路基板）の接続部の構成説明図である。
この実施形態に係る電極間接続構造では、回路基板２側の電極４と電子部品１０側の電極１１とを弾性導電接着剤１にて接続する際に、プリント配線基板側の電極４の少なくとも表層を金にて構成した点が特徴的である。
更に、他の特徴は、電子部品の接続部に対してせん断方向の力を加えることにより、回路基板側電極１１の表面で剥離するように構成した点にある。即ち、回路基板２側の金電極４と、弾性導電接着剤１との接続部にせん断方向の力を加えたときに、弾性導電接着剤１が回路基板側の金電極表面で残渣なく剥離するように構成したものである。
即ち、回路基板２側の電極４の表面を金にて形成し、球状フィラー３０を含んだ弾性導電接着剤１にて接続している。ここで、弾性導電接着剤１は金電極４に対しては接着強度が低くなる特性を持っており、せん断方向の力を加えると金電極界面にて剥離することができる。ここで、２０１２サイズの電子部品を、径５０μｍの球状フィラー３０を含んだ弾性導電接着剤１にて接続し、せん断方向の力を加えたときのせん断歪に対する抵抗特性を図７に示す。せん断歪１．０以上、つまり接続厚５０μｍに対して５０μｍ以上のせん断方向歪に対して安定した接続抵抗特性を示すことができ、優れた応力緩和接続特性を有していることがわかる。但し、それ以上のせん断歪を加えると金電極界面で剥離が発生し、接続部が破断する。このように、あるせん断歪内であれば優れた接続特性を有しているが、それを超えるだけのせん断歪を加えることで、電極界面での剥離が可能となる。一般的に接続部のリペアに対しては、電極上に接着剤の残渣が残り、再接続するためには手直し等が必要となるが、本発明では電極上に残渣がないため、再接続が容易になる。
ここで、金電極４の表面粗さを大きくすることで、弾性導電接着剤１との接着強度が向上し、粗さを小さくすることで接着強度を低下させることができる。 Next, FIG. 6 is a configuration explanatory view of a connection portion of the inter-electrode connection structure (circuit board) according to the implementation embodiments of the present invention.
In the interelectrode connection structure according to this embodiment, when the electrode 4 on the circuit board 2 side and the electrode 11 on the electronic component 10 side are connected with the elastic conductive adhesive 1, at least the surface layer of the electrode 4 on the printed wiring board side. The point is that it is made of gold.
Furthermore, another feature is that it is configured to peel off on the surface of the circuit board side electrode 11 by applying a shearing direction force to the connection part of the electronic component. That is, when a shearing force is applied to the connection portion between the gold electrode 4 on the circuit board 2 side and the elastic conductive adhesive 1, the elastic conductive adhesive 1 is peeled off without residue on the surface of the gold electrode on the circuit board side. It is comprised as follows.
That is, the surface of the electrode 4 on the circuit board 2 side is formed of gold and connected by the elastic conductive adhesive 1 including the spherical filler 30. Here, the elastic conductive adhesive 1 has a property of lowering the adhesive strength with respect to the gold electrode 4, and can be peeled off at the gold electrode interface when a force in the shear direction is applied. Here, FIG. 7 shows resistance characteristics against shear strain when a 2012-size electronic component is connected by the elastic conductive adhesive 1 including the spherical filler 30 having a diameter of 50 μm and a force in the shear direction is applied. It can be seen that a stable connection resistance characteristic can be exhibited with respect to a shear strain of 1.0 or more, that is, a shear direction strain of 50 μm or more with respect to a connection thickness of 50 μm, and it has excellent stress relaxation connection characteristics. However, if more shear strain is applied, peeling occurs at the gold electrode interface, and the connecting portion is broken. Thus, although it has the outstanding connection characteristic if it exists in a certain shear strain, peeling at an electrode interface is attained by adding the shear strain only exceeding it. Generally, for the repair of the connection part, an adhesive residue remains on the electrode, and reworking is necessary to reconnect, but in the present invention there is no residue on the electrode, so reconnection is not possible. It becomes easy.
Here, by increasing the surface roughness of the gold electrode 4, the adhesive strength with the elastic conductive adhesive 1 is improved, and by decreasing the roughness, the adhesive strength can be reduced.

次に、図８は本発明の他の参考実施形態の説明図である。
この実施形態は、弾性導電接着剤１による電極４、１１間の接続部周辺を、ゴム状弾性樹脂４０にて封止した構成が特徴的である。
この実施形態の電極間接続構造では、球状フィラー３０を含む弾性導電接着剤１にて電子部品１０を回路基板２上に接続した構造において、接続部周囲（外面）をゴム状弾性樹脂４０にて被覆して封止している。弾性導電接着剤接続部は優れた応力緩和性能を有しており、せん断方向の応力が加わっても変形することで緩和できる。ここで、ゴム状弾性樹脂４０による封止、及び部品底部空間へのアンダーフィル（樹脂充填）を行うに際して、弾性率の高い樹脂にて封止したりアンダーフィルすると、外部応力が接着界面にかかって界面剥離を発生させ、それに準じて弾性導電接着剤接続部も界面剥離等の破断が発生してしまう。このため、樹脂封止も弾性率の低いゴム状弾性樹脂にて行い、界面剥離を発生させないことで接続信頼性を向上できる。 Next, FIG. 8 is an explanatory diagram of another reference embodiment of the present invention.
This embodiment is characterized in that the periphery of the connecting portion between the electrodes 4 and 11 by the elastic conductive adhesive 1 is sealed with a rubber-like elastic resin 40.
In the interelectrode connection structure of this embodiment, in the structure in which the electronic component 10 is connected to the circuit board 2 by the elastic conductive adhesive 1 including the spherical filler 30, the periphery (outer surface) of the connection portion is formed by the rubber elastic resin 40. Covered and sealed. The elastic conductive adhesive connecting portion has excellent stress relaxation performance and can be relaxed by deformation even when stress in the shear direction is applied. Here, when sealing with the rubber-like elastic resin 40 and underfilling (resin filling) into the part bottom space, if sealing is performed with a resin having a high elastic modulus or underfilling, external stress is applied to the adhesive interface. Interfacial peeling occurs, and the elastic conductive adhesive connecting portion also breaks in accordance with the interface peeling. For this reason, resin sealing is also performed with a rubber-like elastic resin having a low elastic modulus, and connection reliability can be improved by not causing interface peeling.

本発明の参考実施形態に係る弾性導電接着剤と、電極間接続構造（電気回路構造物）の構成を説明する断面図。Sectional drawing explaining the structure of the elastic conductive adhesive which concerns on reference embodiment of this invention, and an interelectrode connection structure (electric circuit structure). 本発明の参考実施形態に係る弾性導電接着剤を用いた電極間の接続構造におけるせん断歪みと抵抗特性との関係をグラフで示す図。The figure which shows the relationship between the shear distortion in the connection structure between electrodes using the elastic conductive adhesive which concerns on reference embodiment of this invention, and a resistance characteristic with a graph. 本発明の他の参考実施形態に係る電極間接続構造を示す断面図。Sectional drawing which shows the connection structure between electrodes which concerns on other reference embodiment of this invention. （ａ）及び（ｂ）は夫々本発明の他の参考実施形態に係る球状フィラーの説明図。(A) And (b) is explanatory drawing of the spherical filler which concerns on other reference embodiment of this invention, respectively. 本発明の他の参考実施形態に係る弾性導電接着剤の要部構成を示す拡大図。The enlarged view which shows the principal part structure of the elastic conductive adhesive which concerns on other reference embodiment of this invention. 本発明の実施形態に係る電極間接続構造（回路基板）の接続部の構成説明図。Diagram illustrating the configuration of a connection portion of the inter-electrode connecting structure according to the implementation mode of the present invention (circuit board). せん断方向の力を加えたときのせん断歪に対する抵抗特性を示す図。The figure which shows the resistance characteristic with respect to the shearing strain when the force of a shear direction is applied. 本発明の他の参考実施形態の説明図。Explanatory drawing of other reference embodiment of this invention.

符号の説明Explanation of symbols

１ 電極間接続構造（電気回路構造物）、２ 電気回路基板、３ 絶縁基板、４ 電極、１０ 電子部品、１１ 電極、２０ 弾性導電接着剤、２１ ゴム状弾性樹脂、２２ 針形状導電性フィラー、３０ 球状フィラー、３１ 非導電性コア材、３２ 金属被覆層、３２ａ 金属フィラー、３２ｂ 金属導電膜、３３ 金属微粒子。   DESCRIPTION OF SYMBOLS 1 Interelectrode connection structure (electric circuit structure), 2 Electric circuit board, 3 Insulating board, 4 Electrode, 10 Electronic component, 11 Electrode, 20 Elastic conductive adhesive, 21 Rubber-like elastic resin, 22 Needle-shaped conductive filler, 30 spherical filler, 31 non-conductive core material, 32 metal coating layer, 32a metal filler, 32b metal conductive film, 33 metal fine particles.

Claims (14)

弾性導電接着剤を用いて２つの電極間を電気的機械的に接続する電極間接続構造であって、
前記弾性導電接着剤は、ゴム状弾性樹脂に、多数の一軸方向に伸びた針形状導電性フィラーと、針形状導電性フィラーの径よりも直径が大きい球状フィラーを混在させた構成を有し、
前記弾性導電接着剤に含まれる球状フィラーの一部が前記２つの電極間に直接接触した状態で接続されているとともに、
前記２つの電極の内の一方は回路基板側の電極であり、他方の電極は電子部品側の電極であり、前記回路基板側の電極は表層を金にて構成した金電極であることを特徴とする電極間接続構造。 An interelectrode connection structure in which two electrodes are electrically and mechanically connected using an elastic conductive adhesive,
The elastic conductive adhesive has a configuration in which a rubber-like elastic resin is mixed with a large number of needle-shaped conductive fillers extending in a uniaxial direction and a spherical filler having a diameter larger than the diameter of the needle-shaped conductive filler ,
A part of the spherical filler contained in the elastic conductive adhesive is connected in a state of direct contact between the two electrodes,
One of the two electrodes is an electrode on the circuit board side, the other electrode is an electrode on the electronic component side, and the electrode on the circuit board side is a gold electrode having a surface layer made of gold. Interelectrode connection structure . 前記針形状導電性フィラーは、径１μｍ以下のウィスカの少なくとも最表面に金属被覆膜を形成した構成を備えていることを特徴とする請求項１に記載の電極間接続構造。 The interelectrode connection structure according to claim 1, wherein the needle-shaped conductive filler has a configuration in which a metal coating film is formed on at least the outermost surface of a whisker having a diameter of 1 µm or less. 前記球状フィラーの直径は、５〜１００μｍであることを特徴とする請求項１、又は２記載の電極間接続構造。 The interelectrode connection structure according to claim 1, wherein the spherical filler has a diameter of 5 to 100 μm. 前記球状フィラーは、少なくともその一部がゴム状弾性樹脂から構成されていることを特徴とする請求項１、２又は３に記載の電極間接続構造。 4. The interelectrode connection structure according to claim 1, wherein at least a part of the spherical filler is made of a rubber-like elastic resin. 前記球状フィラーの少なくとも一部を構成するゴム状弾性樹脂の弾性率は、ゴム状弾性樹脂に針形状導電性フィラーを混練した導電性接着剤よりも低弾性率であることを特徴とする請求項４に記載の電極間接続構造。 The elastic modulus of a rubber-like elastic resin constituting at least a part of the spherical filler is lower than that of a conductive adhesive obtained by kneading a needle-like conductive filler in a rubber-like elastic resin. 4. The interelectrode connection structure according to 4 . 前記球状フィラーの全体、又は少なくともその一部が導電性を有していることを特徴とする請求項１、２、３、４又は５に記載の電極間接続構造。 6. The interelectrode connection structure according to claim 1, 2, 3, 4, or 5, wherein the whole or at least part of the spherical filler has conductivity. 前記球状フィラーは、非導電性コア材と、非導電性コア材の表面に形成された金属被覆層と、から構成されていることを特徴とする請求項６に記載の電極間接続構造。 The interelectrode connection structure according to claim 6, wherein the spherical filler includes a non-conductive core material and a metal coating layer formed on a surface of the non-conductive core material. 前記非導電性コア材はゴム状弾性樹脂からなり、前記金属被覆層は非導電性コア材の表面に付着した金属フィラーからなることを特徴とする請求項７に記載の電極間接続構造。 The interelectrode connection structure according to claim 7, wherein the nonconductive core material is made of a rubber-like elastic resin, and the metal coating layer is made of a metal filler attached to the surface of the nonconductive core material. 前記非導電性コア材は、ゴム状弾性樹脂からなり、
前記金属被覆層は、非導電性コア材の表層に付着した金属フィラーと、金属フィラーを付着させた非導電性コア材表面に無電解メッキにて被覆形成した金属導電膜と、からなることを特徴とする請求項７に記載の電極間接続構造。 The non-conductive core material is made of a rubber-like elastic resin,
The metal coating layer is composed of a metal filler attached to the surface layer of the non-conductive core material, and a metal conductive film formed by electroless plating on the surface of the non-conductive core material to which the metal filler is attached. The interelectrode connection structure according to claim 7, characterized in that: 前記球状フィラー表面の金属被覆層には、段差が０．１〜１μｍの範囲の凹凸が形成されていることを特徴とする請求項７、８又は９に記載の電極間接続構造。 10. The interelectrode connection structure according to claim 7, wherein the metal coating layer on the surface of the spherical filler is provided with unevenness having a level difference of 0.1 to 1 μm. 前記金属被覆層表面に、直径１００ｎｍ以下の金属微粒子が付着していることを特徴とする請求項７、８、又は９に記載の電極間接続構造。 10. The interelectrode connection structure according to claim 7, wherein metal fine particles having a diameter of 100 nm or less are adhered to the surface of the metal coating layer. 前記球状フィラー表面に対して金属微粒子が融着するとともに、金属微粒子の一部が針形状導電性接着剤とも融着していることを特徴とする請求項１１に記載の電極間接続構造。  12. The interelectrode connection structure according to claim 11, wherein metal fine particles are fused to the surface of the spherical filler, and part of the metal fine particles are also fused to the needle-shaped conductive adhesive. 前記回路基板側の金電極と、前記弾性導電接着剤との接続部にせんだん方向の力を加えたときに、前記弾性導電接着剤が前記回路基板側の金電極表面で残渣なく剥離するように構成したことを特徴とする請求項１乃至１２に記載の電極間接続構造。  When a force in a thin direction is applied to the connection portion between the gold electrode on the circuit board side and the elastic conductive adhesive, the elastic conductive adhesive is peeled off without residue on the surface of the gold electrode on the circuit board side. The interelectrode connection structure according to claim 1, wherein the interelectrode connection structure is configured as described above. 前記弾性導電接着剤による電極間の接続部周辺をゴム状弾性樹脂にて封止したことを特徴とする請求項１、１２又は１３に記載の電極間接続構造。  14. The interelectrode connection structure according to claim 1, wherein a periphery of a connection portion between the electrodes by the elastic conductive adhesive is sealed with a rubber-like elastic resin.
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JP5168110B2 (en) * 2008-11-28 2013-03-21 株式会社デンソー Manufacturing method of electronic device
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Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5271177A (en) * 1975-12-10 1977-06-14 Seiko Epson Corp Semiconductor device
JPH05315397A (en) * 1992-05-08 1993-11-26 Matsushita Electric Ind Co Ltd Sealing method and sealing structure of semiconductor device
JPH0855514A (en) * 1993-12-16 1996-02-27 Shin Etsu Polymer Co Ltd Conductive particle and anisotropic conductive adhesive using it
JP2000357854A (en) * 1999-06-15 2000-12-26 Mitsubishi Electric Corp Fpc for electrode connection and display device
JP2004051755A (en) * 2002-07-18 2004-02-19 Ricoh Co Ltd Elastic electrical conductive resin and elastic electrical conductive joint structure
JP2004107728A (en) * 2002-09-18 2004-04-08 Ebara Corp Joining material and joining method
JP2004165414A (en) * 2002-11-13 2004-06-10 Ricoh Co Ltd Mounting structure, optical sensor module and optical sensor module mounting structure
JP2004193250A (en) * 2002-12-10 2004-07-08 Hitachi Chem Co Ltd Conductive paste and semiconductor device using it

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5271177A (en) * 1975-12-10 1977-06-14 Seiko Epson Corp Semiconductor device
JPH05315397A (en) * 1992-05-08 1993-11-26 Matsushita Electric Ind Co Ltd Sealing method and sealing structure of semiconductor device
JPH0855514A (en) * 1993-12-16 1996-02-27 Shin Etsu Polymer Co Ltd Conductive particle and anisotropic conductive adhesive using it
JP2000357854A (en) * 1999-06-15 2000-12-26 Mitsubishi Electric Corp Fpc for electrode connection and display device
JP2004051755A (en) * 2002-07-18 2004-02-19 Ricoh Co Ltd Elastic electrical conductive resin and elastic electrical conductive joint structure
JP2004107728A (en) * 2002-09-18 2004-04-08 Ebara Corp Joining material and joining method
JP2004165414A (en) * 2002-11-13 2004-06-10 Ricoh Co Ltd Mounting structure, optical sensor module and optical sensor module mounting structure
JP2004193250A (en) * 2002-12-10 2004-07-08 Hitachi Chem Co Ltd Conductive paste and semiconductor device using it

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